6 @documentencoding UTF-8
7 @settitle GNU Guix Reference Manual
12 @c Identifier of the OpenPGP key used to sign tarballs and such.
13 @set OPENPGP-SIGNING-KEY-ID 3CE464558A84FDC69DB40CFB090B11993D9AEBB5
16 Copyright @copyright{} 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès@*
17 Copyright @copyright{} 2013, 2014, 2016 Andreas Enge@*
18 Copyright @copyright{} 2013 Nikita Karetnikov@*
19 Copyright @copyright{} 2014, 2015, 2016 Alex Kost@*
20 Copyright @copyright{} 2015, 2016 Mathieu Lirzin@*
21 Copyright @copyright{} 2014 Pierre-Antoine Rault@*
22 Copyright @copyright{} 2015 Taylan Ulrich Bayırlı/Kammer@*
23 Copyright @copyright{} 2015, 2016, 2017 Leo Famulari@*
24 Copyright @copyright{} 2015, 2016, 2017 Ricardo Wurmus@*
25 Copyright @copyright{} 2016 Ben Woodcroft@*
26 Copyright @copyright{} 2016 Chris Marusich@*
27 Copyright @copyright{} 2016, 2017 Efraim Flashner@*
28 Copyright @copyright{} 2016 John Darrington@*
29 Copyright @copyright{} 2016 ng0@*
30 Copyright @copyright{} 2016 Jan Nieuwenhuizen@*
31 Copyright @copyright{} 2016 Julien Lepiller@*
32 Copyright @copyright{} 2016 Alex ter Weele@*
33 Copyright @copyright{} 2017 Clément Lassieur@*
34 Copyright @copyright{} 2017 Mathieu Othacehe@*
35 Copyright @copyright{} 2017 Federico Beffa@*
36 Copyright @copyright{} 2017 Carlo Zancanaro@*
37 Copyright @copyright{} 2017 Thomas Danckaert@*
38 Copyright @copyright{} 2017 humanitiesNerd@*
39 Copyright @copyright{} 2017 Christopher Allan Webber@*
40 Copyright @copyright{} 2017 Marius Bakke@*
41 Copyright @copyright{} 2017 Hartmut Goebel
43 Permission is granted to copy, distribute and/or modify this document
44 under the terms of the GNU Free Documentation License, Version 1.3 or
45 any later version published by the Free Software Foundation; with no
46 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
47 copy of the license is included in the section entitled ``GNU Free
48 Documentation License''.
51 @dircategory System administration
53 * Guix: (guix). Manage installed software and system configuration.
54 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
55 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
56 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
57 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
60 @dircategory Software development
62 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
63 * guix build: (guix)Invoking guix build. Building packages.
64 * guix pack: (guix)Invoking guix pack. Creating binary bundles.
68 @title GNU Guix Reference Manual
69 @subtitle Using the GNU Guix Functional Package Manager
70 @author The GNU Guix Developers
73 @vskip 0pt plus 1filll
74 Edition @value{EDITION} @*
82 @c *********************************************************************
86 This document describes GNU Guix version @value{VERSION}, a functional
87 package management tool written for the GNU system.
90 * Introduction:: What is Guix about?
91 * Installation:: Installing Guix.
92 * Package Management:: Package installation, upgrade, etc.
93 * Programming Interface:: Using Guix in Scheme.
94 * Utilities:: Package management commands.
95 * GNU Distribution:: Software for your friendly GNU system.
96 * Contributing:: Your help needed!
98 * Acknowledgments:: Thanks!
99 * GNU Free Documentation License:: The license of this manual.
100 * Concept Index:: Concepts.
101 * Programming Index:: Data types, functions, and variables.
104 --- The Detailed Node Listing ---
108 * Binary Installation:: Getting Guix running in no time!
109 * Requirements:: Software needed to build and run Guix.
110 * Running the Test Suite:: Testing Guix.
111 * Setting Up the Daemon:: Preparing the build daemon's environment.
112 * Invoking guix-daemon:: Running the build daemon.
113 * Application Setup:: Application-specific setup.
115 Setting Up the Daemon
117 * Build Environment Setup:: Preparing the isolated build environment.
118 * Daemon Offload Setup:: Offloading builds to remote machines.
122 * Features:: How Guix will make your life brighter.
123 * Invoking guix package:: Package installation, removal, etc.
124 * Substitutes:: Downloading pre-built binaries.
125 * Packages with Multiple Outputs:: Single source package, multiple outputs.
126 * Invoking guix gc:: Running the garbage collector.
127 * Invoking guix pull:: Fetching the latest Guix and distribution.
128 * Invoking guix pack:: Creating software bundles.
129 * Invoking guix archive:: Exporting and importing store files.
131 Programming Interface
133 * Defining Packages:: Defining new packages.
134 * Build Systems:: Specifying how packages are built.
135 * The Store:: Manipulating the package store.
136 * Derivations:: Low-level interface to package derivations.
137 * The Store Monad:: Purely functional interface to the store.
138 * G-Expressions:: Manipulating build expressions.
142 * package Reference :: The package data type.
143 * origin Reference:: The origin data type.
147 * Invoking guix build:: Building packages from the command line.
148 * Invoking guix edit:: Editing package definitions.
149 * Invoking guix download:: Downloading a file and printing its hash.
150 * Invoking guix hash:: Computing the cryptographic hash of a file.
151 * Invoking guix import:: Importing package definitions.
152 * Invoking guix refresh:: Updating package definitions.
153 * Invoking guix lint:: Finding errors in package definitions.
154 * Invoking guix size:: Profiling disk usage.
155 * Invoking guix graph:: Visualizing the graph of packages.
156 * Invoking guix environment:: Setting up development environments.
157 * Invoking guix publish:: Sharing substitutes.
158 * Invoking guix challenge:: Challenging substitute servers.
159 * Invoking guix copy:: Copying to and from a remote store.
160 * Invoking guix container:: Process isolation.
161 * Invoking guix weather:: Assessing substitute availability.
163 Invoking @command{guix build}
165 * Common Build Options:: Build options for most commands.
166 * Package Transformation Options:: Creating variants of packages.
167 * Additional Build Options:: Options specific to 'guix build'.
168 * Debugging Build Failures:: Real life packaging experience.
172 * System Installation:: Installing the whole operating system.
173 * System Configuration:: Configuring the operating system.
174 * Documentation:: Browsing software user manuals.
175 * Installing Debugging Files:: Feeding the debugger.
176 * Security Updates:: Deploying security fixes quickly.
177 * Package Modules:: Packages from the programmer's viewpoint.
178 * Packaging Guidelines:: Growing the distribution.
179 * Bootstrapping:: GNU/Linux built from scratch.
180 * Porting:: Targeting another platform or kernel.
184 * Limitations:: What you can expect.
185 * Hardware Considerations:: Supported hardware.
186 * USB Stick Installation:: Preparing the installation medium.
187 * Preparing for Installation:: Networking, partitioning, etc.
188 * Proceeding with the Installation:: The real thing.
189 * Installing GuixSD in a VM:: GuixSD playground.
190 * Building the Installation Image:: How this comes to be.
194 * Using the Configuration System:: Customizing your GNU system.
195 * operating-system Reference:: Detail of operating-system declarations.
196 * File Systems:: Configuring file system mounts.
197 * Mapped Devices:: Block device extra processing.
198 * User Accounts:: Specifying user accounts.
199 * Locales:: Language and cultural convention settings.
200 * Services:: Specifying system services.
201 * Setuid Programs:: Programs running with root privileges.
202 * X.509 Certificates:: Authenticating HTTPS servers.
203 * Name Service Switch:: Configuring libc's name service switch.
204 * Initial RAM Disk:: Linux-Libre bootstrapping.
205 * Bootloader Configuration:: Configuring the boot loader.
206 * Invoking guix system:: Instantiating a system configuration.
207 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
208 * Defining Services:: Adding new service definitions.
212 * Base Services:: Essential system services.
213 * Scheduled Job Execution:: The mcron service.
214 * Log Rotation:: The rottlog service.
215 * Networking Services:: Network setup, SSH daemon, etc.
216 * X Window:: Graphical display.
217 * Printing Services:: Local and remote printer support.
218 * Desktop Services:: D-Bus and desktop services.
219 * Database Services:: SQL databases.
220 * Mail Services:: IMAP, POP3, SMTP, and all that.
221 * Messaging Services:: Messaging services.
222 * Monitoring Services:: Monitoring services.
223 * Kerberos Services:: Kerberos services.
224 * Web Services:: Web servers.
225 * DNS Services:: DNS daemons.
226 * VPN Services:: VPN daemons.
227 * Network File System:: NFS related services.
228 * Continuous Integration:: The Cuirass service.
229 * Power management Services:: The TLP tool.
230 * Miscellaneous Services:: Other services.
234 * Service Composition:: The model for composing services.
235 * Service Types and Services:: Types and services.
236 * Service Reference:: API reference.
237 * Shepherd Services:: A particular type of service.
241 * Software Freedom:: What may go into the distribution.
242 * Package Naming:: What's in a name?
243 * Version Numbers:: When the name is not enough.
244 * Synopses and Descriptions:: Helping users find the right package.
245 * Python Modules:: A touch of British comedy.
246 * Perl Modules:: Little pearls.
247 * Java Packages:: Coffee break.
248 * Fonts:: Fond of fonts.
252 * Building from Git:: The latest and greatest.
253 * Running Guix Before It Is Installed:: Hacker tricks.
254 * The Perfect Setup:: The right tools.
255 * Coding Style:: Hygiene of the contributor.
256 * Submitting Patches:: Share your work.
260 * Programming Paradigm:: How to compose your elements.
261 * Modules:: Where to store your code?
262 * Data Types and Pattern Matching:: Implementing data structures.
263 * Formatting Code:: Writing conventions.
268 @c *********************************************************************
270 @chapter Introduction
273 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
274 using the international phonetic alphabet (IPA).} is a package
275 management tool for the GNU system. Guix makes it easy for unprivileged
276 users to install, upgrade, or remove packages, to roll back to a
277 previous package set, to build packages from source, and generally
278 assists with the creation and maintenance of software environments.
280 @cindex user interfaces
281 Guix provides a command-line package management interface
282 (@pxref{Invoking guix package}), a set of command-line utilities
283 (@pxref{Utilities}), as well as Scheme programming interfaces
284 (@pxref{Programming Interface}).
286 Its @dfn{build daemon} is responsible for building packages on behalf of
287 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
288 binaries from authorized sources (@pxref{Substitutes}).
290 @cindex extensibility of the distribution
291 @cindex customization, of packages
292 Guix includes package definitions for many GNU and non-GNU packages, all
293 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
294 user's computing freedom}. It is @emph{extensible}: users can write
295 their own package definitions (@pxref{Defining Packages}) and make them
296 available as independent package modules (@pxref{Package Modules}). It
297 is also @emph{customizable}: users can @emph{derive} specialized package
298 definitions from existing ones, including from the command line
299 (@pxref{Package Transformation Options}).
301 @cindex Guix System Distribution
303 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
304 where it complements the available tools without interference
305 (@pxref{Installation}), or you can use it as part of the standalone
306 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
307 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
308 system configuration and Guix takes care of instantiating the
309 configuration in a transactional, reproducible, and stateless fashion
310 (@pxref{System Configuration}).
312 @cindex functional package management
313 Under the hood, Guix implements the @dfn{functional package management}
314 discipline pioneered by Nix (@pxref{Acknowledgments}).
315 In Guix, the package build and installation process is seen
316 as a @emph{function}, in the mathematical sense. That function takes inputs,
317 such as build scripts, a compiler, and libraries, and
318 returns an installed package. As a pure function, its result depends
319 solely on its inputs---for instance, it cannot refer to software or
320 scripts that were not explicitly passed as inputs. A build function
321 always produces the same result when passed a given set of inputs. It
322 cannot alter the environment of the running system in
323 any way; for instance, it cannot create, modify, or delete files outside
324 of its build and installation directories. This is achieved by running
325 build processes in isolated environments (or @dfn{containers}), where only their
326 explicit inputs are visible.
329 The result of package build functions is @dfn{cached} in the file
330 system, in a special directory called @dfn{the store} (@pxref{The
331 Store}). Each package is installed in a directory of its own in the
332 store---by default under @file{/gnu/store}. The directory name contains
333 a hash of all the inputs used to build that package; thus, changing an
334 input yields a different directory name.
336 This approach is the foundation for the salient features of Guix: support
337 for transactional package upgrade and rollback, per-user installation, and
338 garbage collection of packages (@pxref{Features}).
341 @c *********************************************************************
343 @chapter Installation
345 @cindex installing Guix
346 GNU Guix is available for download from its website at
347 @url{http://www.gnu.org/software/guix/}. This section describes the
348 software requirements of Guix, as well as how to install it and get
351 Note that this section is concerned with the installation of the package
352 manager, which can be done on top of a running GNU/Linux system. If,
353 instead, you want to install the complete GNU operating system,
354 @pxref{System Installation}.
356 @cindex foreign distro
357 When installed on a running GNU/Linux system---thereafter called a
358 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
359 without interference. Its data lives exclusively in two directories,
360 usually @file{/gnu/store} and @file{/var/guix}; other files on your
361 system, such as @file{/etc}, are left untouched.
363 Once installed, Guix can be updated by running @command{guix pull}
364 (@pxref{Invoking guix pull}).
367 * Binary Installation:: Getting Guix running in no time!
368 * Requirements:: Software needed to build and run Guix.
369 * Running the Test Suite:: Testing Guix.
370 * Setting Up the Daemon:: Preparing the build daemon's environment.
371 * Invoking guix-daemon:: Running the build daemon.
372 * Application Setup:: Application-specific setup.
375 @node Binary Installation
376 @section Binary Installation
378 @cindex installing Guix from binaries
379 This section describes how to install Guix on an arbitrary system from a
380 self-contained tarball providing binaries for Guix and for all its
381 dependencies. This is often quicker than installing from source, which
382 is described in the next sections. The only requirement is to have
385 Installing goes along these lines:
389 @cindex downloading Guix binary
390 Download the binary tarball from
391 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
392 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
393 already running the kernel Linux, and so on.
395 @c The following is somewhat duplicated in ``System Installation''.
396 Make sure to download the associated @file{.sig} file and to verify the
397 authenticity of the tarball against it, along these lines:
400 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
401 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
404 If that command fails because you do not have the required public key,
405 then run this command to import it:
408 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
412 and rerun the @code{gpg --verify} command.
413 @c end authentication part
420 # tar --warning=no-timestamp -xf \
421 guix-binary-@value{VERSION}.@var{system}.tar.xz
422 # mv var/guix /var/ && mv gnu /
425 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
426 The latter contains a ready-to-use profile for @code{root} (see next
429 Do @emph{not} unpack the tarball on a working Guix system since that
430 would overwrite its own essential files.
432 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
433 not emit warnings about ``implausibly old time stamps'' (such
434 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
436 They stem from the fact that all the
437 files in the archive have their modification time set to zero (which
438 means January 1st, 1970.) This is done on purpose to make sure the
439 archive content is independent of its creation time, thus making it
443 Make @code{root}'s profile available under @file{~/.guix-profile}:
446 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
450 Source @file{etc/profile} to augment @code{PATH} and other relevant
451 environment variables:
454 # GUIX_PROFILE=$HOME/.guix-profile \
455 source $GUIX_PROFILE/etc/profile
459 Create the group and user accounts for build users as explained below
460 (@pxref{Build Environment Setup}).
463 Run the daemon, and set it to automatically start on boot.
465 If your host distro uses the systemd init system, this can be achieved
468 @c Versions of systemd that supported symlinked service files are not
469 @c yet widely deployed, so we should suggest that users copy the service
472 @c See this thread for more information:
473 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
476 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
478 # systemctl start guix-daemon && systemctl enable guix-daemon
481 If your host distro uses the Upstart init system:
484 # initctl reload-configuration
485 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
489 Otherwise, you can still start the daemon manually with:
492 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
496 Make the @command{guix} command available to other users on the machine,
500 # mkdir -p /usr/local/bin
502 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
505 It is also a good idea to make the Info version of this manual available
509 # mkdir -p /usr/local/share/info
510 # cd /usr/local/share/info
511 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
515 That way, assuming @file{/usr/local/share/info} is in the search path,
516 running @command{info guix} will open this manual (@pxref{Other Info
517 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
521 @cindex substitutes, authorization thereof
522 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
523 (@pxref{Substitutes}), authorize them:
526 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
530 Each user may need to perform a few additional steps to make their Guix
531 environment ready for use, @pxref{Application Setup}.
534 Voilà, the installation is complete!
536 You can confirm that Guix is working by installing a sample package into
540 # guix package -i hello
543 The @code{guix} package must remain available in @code{root}'s profile,
544 or it would become subject to garbage collection---in which case you
545 would find yourself badly handicapped by the lack of the @command{guix}
546 command. In other words, do not remove @code{guix} by running
547 @code{guix package -r guix}.
549 The binary installation tarball can be (re)produced and verified simply
550 by running the following command in the Guix source tree:
553 make guix-binary.@var{system}.tar.xz
557 ... which, in turn, runs:
560 guix pack -s @var{system} --localstatedir guix
563 @xref{Invoking guix pack}, for more info on this handy tool.
566 @section Requirements
568 This section lists requirements when building Guix from source. The
569 build procedure for Guix is the same as for other GNU software, and is
570 not covered here. Please see the files @file{README} and @file{INSTALL}
571 in the Guix source tree for additional details.
573 GNU Guix depends on the following packages:
576 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
577 later, including 2.2.x;
578 @item @url{http://gnupg.org/, GNU libgcrypt};
580 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
581 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
582 Guile,, gnutls-guile, GnuTLS-Guile});
584 @c FIXME: Specify a version number once a release has been made.
585 @uref{https://gitlab.com/guile-git/guile-git, Guile-Git}, from August
587 @item @url{http://www.gnu.org/software/make/, GNU Make}.
590 The following dependencies are optional:
595 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
596 allow you to use the @command{guix import pypi} command (@pxref{Invoking
597 guix import}). It is of
598 interest primarily for developers and not for casual users.
601 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
602 Support for build offloading (@pxref{Daemon Offload Setup}) and
603 @command{guix copy} (@pxref{Invoking guix copy}) depends on
604 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
605 version 0.10.2 or later.
608 When @url{http://zlib.net, zlib} is available, @command{guix publish}
609 can compress build byproducts (@pxref{Invoking guix publish}).
612 Unless @code{--disable-daemon} was passed to @command{configure}, the
613 following packages are also needed:
616 @item @url{http://sqlite.org, SQLite 3};
617 @item @url{http://www.bzip.org, libbz2};
618 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
622 @cindex state directory
623 When configuring Guix on a system that already has a Guix installation,
624 be sure to specify the same state directory as the existing installation
625 using the @code{--localstatedir} option of the @command{configure}
626 script (@pxref{Directory Variables, @code{localstatedir},, standards,
627 GNU Coding Standards}). The @command{configure} script protects against
628 unintended misconfiguration of @var{localstatedir} so you do not
629 inadvertently corrupt your store (@pxref{The Store}).
631 @cindex Nix, compatibility
632 When a working installation of @url{http://nixos.org/nix/, the Nix package
633 manager} is available, you
634 can instead configure Guix with @code{--disable-daemon}. In that case,
635 Nix replaces the three dependencies above.
637 Guix is compatible with Nix, so it is possible to share the same store
638 between both. To do so, you must pass @command{configure} not only the
639 same @code{--with-store-dir} value, but also the same
640 @code{--localstatedir} value. The latter is essential because it
641 specifies where the database that stores metadata about the store is
642 located, among other things. The default values for Nix are
643 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
644 Note that @code{--disable-daemon} is not required if
645 your goal is to share the store with Nix.
647 @node Running the Test Suite
648 @section Running the Test Suite
651 After a successful @command{configure} and @code{make} run, it is a good
652 idea to run the test suite. It can help catch issues with the setup or
653 environment, or bugs in Guix itself---and really, reporting test
654 failures is a good way to help improve the software. To run the test
661 Test cases can run in parallel: you can use the @code{-j} option of
662 GNU@tie{}make to speed things up. The first run may take a few minutes
663 on a recent machine; subsequent runs will be faster because the store
664 that is created for test purposes will already have various things in
667 It is also possible to run a subset of the tests by defining the
668 @code{TESTS} makefile variable as in this example:
671 make check TESTS="tests/store.scm tests/cpio.scm"
674 By default, tests results are displayed at a file level. In order to
675 see the details of every individual test cases, it is possible to define
676 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
679 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
682 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
683 @file{test-suite.log} file. Please specify the Guix version being used
684 as well as version numbers of the dependencies (@pxref{Requirements}) in
687 Guix also comes with a whole-system test suite that tests complete
688 GuixSD operating system instances. It can only run on systems where
689 Guix is already installed, using:
696 or, again, by defining @code{TESTS} to select a subset of tests to run:
699 make check-system TESTS="basic mcron"
702 These system tests are defined in the @code{(gnu tests @dots{})}
703 modules. They work by running the operating systems under test with
704 lightweight instrumentation in a virtual machine (VM). They can be
705 computationally intensive or rather cheap, depending on whether
706 substitutes are available for their dependencies (@pxref{Substitutes}).
707 Some of them require a lot of storage space to hold VM images.
709 Again in case of test failures, please send @email{bug-guix@@gnu.org}
712 @node Setting Up the Daemon
713 @section Setting Up the Daemon
716 Operations such as building a package or running the garbage collector
717 are all performed by a specialized process, the @dfn{build daemon}, on
718 behalf of clients. Only the daemon may access the store and its
719 associated database. Thus, any operation that manipulates the store
720 goes through the daemon. For instance, command-line tools such as
721 @command{guix package} and @command{guix build} communicate with the
722 daemon (@i{via} remote procedure calls) to instruct it what to do.
724 The following sections explain how to prepare the build daemon's
725 environment. See also @ref{Substitutes}, for information on how to allow
726 the daemon to download pre-built binaries.
729 * Build Environment Setup:: Preparing the isolated build environment.
730 * Daemon Offload Setup:: Offloading builds to remote machines.
733 @node Build Environment Setup
734 @subsection Build Environment Setup
736 @cindex build environment
737 In a standard multi-user setup, Guix and its daemon---the
738 @command{guix-daemon} program---are installed by the system
739 administrator; @file{/gnu/store} is owned by @code{root} and
740 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
741 Guix tools to build packages or otherwise access the store, and the
742 daemon will do it on their behalf, ensuring that the store is kept in a
743 consistent state, and allowing built packages to be shared among users.
746 When @command{guix-daemon} runs as @code{root}, you may not want package
747 build processes themselves to run as @code{root} too, for obvious
748 security reasons. To avoid that, a special pool of @dfn{build users}
749 should be created for use by build processes started by the daemon.
750 These build users need not have a shell and a home directory: they will
751 just be used when the daemon drops @code{root} privileges in build
752 processes. Having several such users allows the daemon to launch
753 distinct build processes under separate UIDs, which guarantees that they
754 do not interfere with each other---an essential feature since builds are
755 regarded as pure functions (@pxref{Introduction}).
757 On a GNU/Linux system, a build user pool may be created like this (using
758 Bash syntax and the @code{shadow} commands):
760 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
761 @c for why `-G' is needed.
763 # groupadd --system guixbuild
764 # for i in `seq -w 1 10`;
766 useradd -g guixbuild -G guixbuild \
767 -d /var/empty -s `which nologin` \
768 -c "Guix build user $i" --system \
774 The number of build users determines how many build jobs may run in
775 parallel, as specified by the @option{--max-jobs} option
776 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
777 @command{guix system vm} and related commands, you may need to add the
778 build users to the @code{kvm} group so they can access @file{/dev/kvm},
779 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
780 (@pxref{Invoking guix system}).
782 The @code{guix-daemon} program may then be run as @code{root} with the
783 following command@footnote{If your machine uses the systemd init system,
784 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
785 file in @file{/etc/systemd/system} will ensure that
786 @command{guix-daemon} is automatically started. Similarly, if your
787 machine uses the Upstart init system, drop the
788 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
789 file in @file{/etc/init}.}:
792 # guix-daemon --build-users-group=guixbuild
797 This way, the daemon starts build processes in a chroot, under one of
798 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
799 environment contains nothing but:
801 @c Keep this list in sync with libstore/build.cc! -----------------------
804 a minimal @code{/dev} directory, created mostly independently from the
805 host @code{/dev}@footnote{``Mostly'', because while the set of files
806 that appear in the chroot's @code{/dev} is fixed, most of these files
807 can only be created if the host has them.};
810 the @code{/proc} directory; it only shows the processes of the container
811 since a separate PID name space is used;
814 @file{/etc/passwd} with an entry for the current user and an entry for
818 @file{/etc/group} with an entry for the user's group;
821 @file{/etc/hosts} with an entry that maps @code{localhost} to
825 a writable @file{/tmp} directory.
828 You can influence the directory where the daemon stores build trees
829 @i{via} the @code{TMPDIR} environment variable. However, the build tree
830 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
831 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
832 This way, the value of @code{TMPDIR} does not leak inside build
833 environments, which avoids discrepancies in cases where build processes
834 capture the name of their build tree.
837 The daemon also honors the @code{http_proxy} environment variable for
838 HTTP downloads it performs, be it for fixed-output derivations
839 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
841 If you are installing Guix as an unprivileged user, it is still possible
842 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
843 However, build processes will not be isolated from one another, and not
844 from the rest of the system. Thus, build processes may interfere with
845 each other, and may access programs, libraries, and other files
846 available on the system---making it much harder to view them as
847 @emph{pure} functions.
850 @node Daemon Offload Setup
851 @subsection Using the Offload Facility
855 When desired, the build daemon can @dfn{offload} derivation builds to
856 other machines running Guix, using the @code{offload} @dfn{build
857 hook}@footnote{This feature is available only when
858 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
860 feature is enabled, a list of user-specified build machines is read from
861 @file{/etc/guix/machines.scm}; every time a build is requested, for
862 instance via @code{guix build}, the daemon attempts to offload it to one
863 of the machines that satisfy the constraints of the derivation, in
864 particular its system type---e.g., @file{x86_64-linux}. Missing
865 prerequisites for the build are copied over SSH to the target machine,
866 which then proceeds with the build; upon success the output(s) of the
867 build are copied back to the initial machine.
869 The @file{/etc/guix/machines.scm} file typically looks like this:
873 (name "eightysix.example.org")
874 (system "x86_64-linux")
875 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
877 (speed 2.)) ;incredibly fast!
880 (name "meeps.example.org")
881 (system "mips64el-linux")
882 (host-key "ssh-rsa AAAAB3Nza@dots{}")
885 (string-append (getenv "HOME")
886 "/.ssh/identity-for-guix"))))
890 In the example above we specify a list of two build machines, one for
891 the @code{x86_64} architecture and one for the @code{mips64el}
894 In fact, this file is---not surprisingly!---a Scheme file that is
895 evaluated when the @code{offload} hook is started. Its return value
896 must be a list of @code{build-machine} objects. While this example
897 shows a fixed list of build machines, one could imagine, say, using
898 DNS-SD to return a list of potential build machines discovered in the
899 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
900 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
903 @deftp {Data Type} build-machine
904 This data type represents build machines to which the daemon may offload
905 builds. The important fields are:
910 The host name of the remote machine.
913 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
916 The user account to use when connecting to the remote machine over SSH.
917 Note that the SSH key pair must @emph{not} be passphrase-protected, to
918 allow non-interactive logins.
921 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
922 This is used to authenticate the machine when we connect to it. It is a
923 long string that looks like this:
926 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
929 If the machine is running the OpenSSH daemon, @command{sshd}, the host
930 key can be found in a file such as
931 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
933 If the machine is running the SSH daemon of GNU@tie{}lsh,
934 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
935 similar file. It can be converted to the OpenSSH format using
936 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
939 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
940 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
945 A number of optional fields may be specified:
949 @item @code{port} (default: @code{22})
950 Port number of SSH server on the machine.
952 @item @code{private-key} (default: @file{~root/.ssh/id_rsa})
953 The SSH private key file to use when connecting to the machine, in
956 Note that the default value is the private key @emph{of the root
957 account}. Make sure it exists if you use the default.
959 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
960 @itemx @code{compression-level} (default: @code{3})
961 The SSH-level compression methods and compression level requested.
963 Note that offloading relies on SSH compression to reduce bandwidth usage
964 when transferring files to and from build machines.
966 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
967 File name of the Unix-domain socket @command{guix-daemon} is listening
970 @item @code{parallel-builds} (default: @code{1})
971 The number of builds that may run in parallel on the machine.
973 @item @code{speed} (default: @code{1.0})
974 A ``relative speed factor''. The offload scheduler will tend to prefer
975 machines with a higher speed factor.
977 @item @code{features} (default: @code{'()})
978 A list of strings denoting specific features supported by the machine.
979 An example is @code{"kvm"} for machines that have the KVM Linux modules
980 and corresponding hardware support. Derivations can request features by
981 name, and they will be scheduled on matching build machines.
986 The @code{guile} command must be in the search path on the build
987 machines. In addition, the Guix modules must be in
988 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
989 this is the case by running:
992 ssh build-machine guile -c "'(use-modules (guix config))'"
995 There is one last thing to do once @file{machines.scm} is in place. As
996 explained above, when offloading, files are transferred back and forth
997 between the machine stores. For this to work, you first need to
998 generate a key pair on each machine to allow the daemon to export signed
999 archives of files from the store (@pxref{Invoking guix archive}):
1002 # guix archive --generate-key
1006 Each build machine must authorize the key of the master machine so that
1007 it accepts store items it receives from the master:
1010 # guix archive --authorize < master-public-key.txt
1014 Likewise, the master machine must authorize the key of each build machine.
1016 All the fuss with keys is here to express pairwise mutual trust
1017 relations between the master and the build machines. Concretely, when
1018 the master receives files from a build machine (and @i{vice versa}), its
1019 build daemon can make sure they are genuine, have not been tampered
1020 with, and that they are signed by an authorized key.
1022 @cindex offload test
1023 To test whether your setup is operational, run this command on the
1030 This will attempt to connect to each of the build machines specified in
1031 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1032 available on each machine, attempt to export to the machine and import
1033 from it, and report any error in the process.
1035 If you want to test a different machine file, just specify it on the
1039 # guix offload test machines-qualif.scm
1042 Last, you can test the subset of the machines whose name matches a
1043 regular expression like this:
1046 # guix offload test machines.scm '\.gnu\.org$'
1049 @node Invoking guix-daemon
1050 @section Invoking @command{guix-daemon}
1052 The @command{guix-daemon} program implements all the functionality to
1053 access the store. This includes launching build processes, running the
1054 garbage collector, querying the availability of a build result, etc. It
1055 is normally run as @code{root} like this:
1058 # guix-daemon --build-users-group=guixbuild
1062 For details on how to set it up, @pxref{Setting Up the Daemon}.
1065 @cindex container, build environment
1066 @cindex build environment
1067 @cindex reproducible builds
1068 By default, @command{guix-daemon} launches build processes under
1069 different UIDs, taken from the build group specified with
1070 @code{--build-users-group}. In addition, each build process is run in a
1071 chroot environment that only contains the subset of the store that the
1072 build process depends on, as specified by its derivation
1073 (@pxref{Programming Interface, derivation}), plus a set of specific
1074 system directories. By default, the latter contains @file{/dev} and
1075 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1076 @dfn{container}: in addition to having its own file system tree, it has
1077 a separate mount name space, its own PID name space, network name space,
1078 etc. This helps achieve reproducible builds (@pxref{Features}).
1080 When the daemon performs a build on behalf of the user, it creates a
1081 build directory under @file{/tmp} or under the directory specified by
1082 its @code{TMPDIR} environment variable; this directory is shared with
1083 the container for the duration of the build. Be aware that using a
1084 directory other than @file{/tmp} can affect build results---for example,
1085 with a longer directory name, a build process that uses Unix-domain
1086 sockets might hit the name length limitation for @code{sun_path}, which
1087 it would otherwise not hit.
1089 The build directory is automatically deleted upon completion, unless the
1090 build failed and the client specified @option{--keep-failed}
1091 (@pxref{Invoking guix build, @option{--keep-failed}}).
1093 The following command-line options are supported:
1096 @item --build-users-group=@var{group}
1097 Take users from @var{group} to run build processes (@pxref{Setting Up
1098 the Daemon, build users}).
1100 @item --no-substitutes
1102 Do not use substitutes for build products. That is, always build things
1103 locally instead of allowing downloads of pre-built binaries
1104 (@pxref{Substitutes}).
1106 By default substitutes are used, unless the client---such as the
1107 @command{guix package} command---is explicitly invoked with
1108 @code{--no-substitutes}.
1110 When the daemon runs with @code{--no-substitutes}, clients can still
1111 explicitly enable substitution @i{via} the @code{set-build-options}
1112 remote procedure call (@pxref{The Store}).
1114 @item --substitute-urls=@var{urls}
1115 @anchor{daemon-substitute-urls}
1116 Consider @var{urls} the default whitespace-separated list of substitute
1117 source URLs. When this option is omitted,
1118 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1119 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1121 This means that substitutes may be downloaded from @var{urls}, as long
1122 as they are signed by a trusted signature (@pxref{Substitutes}).
1125 @item --no-build-hook
1126 Do not use the @dfn{build hook}.
1128 The build hook is a helper program that the daemon can start and to
1129 which it submits build requests. This mechanism is used to offload
1130 builds to other machines (@pxref{Daemon Offload Setup}).
1132 @item --cache-failures
1133 Cache build failures. By default, only successful builds are cached.
1135 When this option is used, @command{guix gc --list-failures} can be used
1136 to query the set of store items marked as failed; @command{guix gc
1137 --clear-failures} removes store items from the set of cached failures.
1138 @xref{Invoking guix gc}.
1140 @item --cores=@var{n}
1142 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1145 The default value is @code{0}, but it may be overridden by clients, such
1146 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1149 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1150 in the build process, which can then use it to exploit internal
1151 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1153 @item --max-jobs=@var{n}
1155 Allow at most @var{n} build jobs in parallel. The default value is
1156 @code{1}. Setting it to @code{0} means that no builds will be performed
1157 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1158 Setup}), or simply fail.
1160 @item --max-silent-time=@var{seconds}
1161 When the build or substitution process remains silent for more than
1162 @var{seconds}, terminate it and report a build failure.
1164 The default value is @code{0}, which disables the timeout.
1166 The value specified here can be overridden by clients (@pxref{Common
1167 Build Options, @code{--max-silent-time}}).
1169 @item --timeout=@var{seconds}
1170 Likewise, when the build or substitution process lasts for more than
1171 @var{seconds}, terminate it and report a build failure.
1173 The default value is @code{0}, which disables the timeout.
1175 The value specified here can be overridden by clients (@pxref{Common
1176 Build Options, @code{--timeout}}).
1178 @item --rounds=@var{N}
1179 Build each derivation @var{n} times in a row, and raise an error if
1180 consecutive build results are not bit-for-bit identical. Note that this
1181 setting can be overridden by clients such as @command{guix build}
1182 (@pxref{Invoking guix build}).
1184 When used in conjunction with @option{--keep-failed}, the differing
1185 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1186 This makes it easy to look for differences between the two results.
1189 Produce debugging output.
1191 This is useful to debug daemon start-up issues, but then it may be
1192 overridden by clients, for example the @code{--verbosity} option of
1193 @command{guix build} (@pxref{Invoking guix build}).
1195 @item --chroot-directory=@var{dir}
1196 Add @var{dir} to the build chroot.
1198 Doing this may change the result of build processes---for instance if
1199 they use optional dependencies found in @var{dir} when it is available,
1200 and not otherwise. For that reason, it is not recommended to do so.
1201 Instead, make sure that each derivation declares all the inputs that it
1204 @item --disable-chroot
1205 Disable chroot builds.
1207 Using this option is not recommended since, again, it would allow build
1208 processes to gain access to undeclared dependencies. It is necessary,
1209 though, when @command{guix-daemon} is running under an unprivileged user
1212 @item --disable-log-compression
1213 Disable compression of the build logs.
1215 Unless @code{--lose-logs} is used, all the build logs are kept in the
1216 @var{localstatedir}. To save space, the daemon automatically compresses
1217 them with bzip2 by default. This option disables that.
1219 @item --disable-deduplication
1220 @cindex deduplication
1221 Disable automatic file ``deduplication'' in the store.
1223 By default, files added to the store are automatically ``deduplicated'':
1224 if a newly added file is identical to another one found in the store,
1225 the daemon makes the new file a hard link to the other file. This can
1226 noticeably reduce disk usage, at the expense of slightly increased
1227 input/output load at the end of a build process. This option disables
1230 @item --gc-keep-outputs[=yes|no]
1231 Tell whether the garbage collector (GC) must keep outputs of live
1234 When set to ``yes'', the GC will keep the outputs of any live derivation
1235 available in the store---the @code{.drv} files. The default is ``no'',
1236 meaning that derivation outputs are kept only if they are GC roots.
1238 @item --gc-keep-derivations[=yes|no]
1239 Tell whether the garbage collector (GC) must keep derivations
1240 corresponding to live outputs.
1242 When set to ``yes'', as is the case by default, the GC keeps
1243 derivations---i.e., @code{.drv} files---as long as at least one of their
1244 outputs is live. This allows users to keep track of the origins of
1245 items in their store. Setting it to ``no'' saves a bit of disk space.
1247 Note that when both @code{--gc-keep-derivations} and
1248 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1249 prerequisites (the sources, compiler, libraries, and other build-time
1250 tools) of live objects in the store, regardless of whether these
1251 prerequisites are live. This is convenient for developers since it
1252 saves rebuilds or downloads.
1254 @item --impersonate-linux-2.6
1255 On Linux-based systems, impersonate Linux 2.6. This means that the
1256 kernel's @code{uname} system call will report 2.6 as the release number.
1258 This might be helpful to build programs that (usually wrongfully) depend
1259 on the kernel version number.
1262 Do not keep build logs. By default they are kept under
1263 @code{@var{localstatedir}/guix/log}.
1265 @item --system=@var{system}
1266 Assume @var{system} as the current system type. By default it is the
1267 architecture/kernel pair found at configure time, such as
1268 @code{x86_64-linux}.
1270 @item --listen=@var{endpoint}
1271 Listen for connections on @var{endpoint}. @var{endpoint} is interpreted
1272 as the file name of a Unix-domain socket if it starts with
1273 @code{/} (slash sign). Otherwise, @var{endpoint} is interpreted as a
1274 host name or host name and port to listen to. Here are a few examples:
1277 @item --listen=/gnu/var/daemon
1278 Listen for connections on the @file{/gnu/var/daemon} Unix-domain socket,
1279 creating it if needed.
1281 @item --listen=localhost
1282 @cindex daemon, remote access
1283 @cindex remote access to the daemon
1284 @cindex daemon, cluster setup
1285 @cindex clusters, daemon setup
1286 Listen for TCP connections on the network interface corresponding to
1287 @code{localhost}, on port 44146.
1289 @item --listen=128.0.0.42:1234
1290 Listen for TCP connections on the network interface corresponding to
1291 @code{128.0.0.42}, on port 1234.
1294 This option can be repeated multiple times, in which case
1295 @command{guix-daemon} accepts connections on all the specified
1296 endpoints. Users can tell client commands what endpoint to connect to
1297 by setting the @code{GUIX_DAEMON_SOCKET} environment variable
1298 (@pxref{The Store, @code{GUIX_DAEMON_SOCKET}}).
1301 The daemon protocol is @emph{unauthenticated and unencrypted}. Using
1302 @code{--listen=@var{host}} is suitable on local networks, such as
1303 clusters, where only trusted nodes may connect to the build daemon. In
1304 other cases where remote access to the daemon is needed, we recommend
1305 using Unix-domain sockets along with SSH.
1308 When @code{--listen} is omitted, @command{guix-daemon} listens for
1309 connections on the Unix-domain socket located at
1310 @file{@var{localstatedir}/daemon-socket/socket}.
1314 @node Application Setup
1315 @section Application Setup
1317 @cindex foreign distro
1318 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1319 so-called @dfn{foreign distro}---a few additional steps are needed to
1320 get everything in place. Here are some of them.
1324 @anchor{locales-and-locpath}
1325 @cindex locales, when not on GuixSD
1327 @vindex GUIX_LOCPATH
1328 Packages installed @i{via} Guix will not use the locale data of the
1329 host system. Instead, you must first install one of the locale packages
1330 available with Guix and then define the @code{GUIX_LOCPATH} environment
1334 $ guix package -i glibc-locales
1335 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1338 Note that the @code{glibc-locales} package contains data for all the
1339 locales supported by the GNU@tie{}libc and weighs in at around
1340 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1341 limited to a few UTF-8 locales.
1343 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1344 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1345 Manual}). There are two important differences though:
1349 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1350 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1351 to make sure the programs of the foreign distro will not end up loading
1352 incompatible locale data.
1355 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1356 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1357 should your Guix profile contain a mixture of programs linked against
1358 different libc version, each libc version will only try to load locale
1359 data in the right format.
1362 This is important because the locale data format used by different libc
1363 versions may be incompatible.
1365 @subsection Name Service Switch
1367 @cindex name service switch, glibc
1368 @cindex NSS (name service switch), glibc
1369 @cindex nscd (name service caching daemon)
1370 @cindex name service caching daemon (nscd)
1371 When using Guix on a foreign distro, we @emph{strongly recommend} that
1372 the system run the GNU C library's @dfn{name service cache daemon},
1373 @command{nscd}, which should be listening on the
1374 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1375 installed with Guix may fail to look up host names or user accounts, or
1376 may even crash. The next paragraphs explain why.
1378 @cindex @file{nsswitch.conf}
1379 The GNU C library implements a @dfn{name service switch} (NSS), which is
1380 an extensible mechanism for ``name lookups'' in general: host name
1381 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1382 The GNU C Library Reference Manual}).
1384 @cindex Network information service (NIS)
1385 @cindex NIS (Network information service)
1386 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1387 lookup implementations: for example, the @code{nss-mdns} plugin allow
1388 resolution of @code{.local} host names, the @code{nis} plugin allows
1389 user account lookup using the Network information service (NIS), and so
1390 on. These extra ``lookup services'' are configured system-wide in
1391 @file{/etc/nsswitch.conf}, and all the programs running on the system
1392 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1395 When they perform a name lookup---for instance by calling the
1396 @code{getaddrinfo} function in C---applications first try to connect to
1397 the nscd; on success, nscd performs name lookups on their behalf. If
1398 the nscd is not running, then they perform the name lookup by
1399 themselves, by loading the name lookup services into their own address
1400 space and running it. These name lookup services---the
1401 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1402 the host system's C library, rather than from the C library the
1403 application is linked against (the C library coming from Guix).
1405 And this is where the problem is: if your application is linked against
1406 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1407 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1408 likely crash or have its name lookups fail unexpectedly.
1410 Running @command{nscd} on the system, among other advantages, eliminates
1411 this binary incompatibility problem because those @code{libnss_*.so}
1412 files are loaded in the @command{nscd} process, not in applications
1415 @subsection X11 Fonts
1418 The majority of graphical applications use Fontconfig to locate and
1419 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1420 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1421 by default. Thus, to allow graphical applications installed with Guix
1422 to display fonts, you have to install fonts with Guix as well.
1423 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1424 @code{font-gnu-freefont-ttf}.
1426 To display text written in Chinese languages, Japanese, or Korean in
1427 graphical applications, consider installing
1428 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1429 has multiple outputs, one per language family (@pxref{Packages with
1430 Multiple Outputs}). For instance, the following command installs fonts
1431 for Chinese languages:
1434 guix package -i font-adobe-source-han-sans:cn
1437 @cindex @code{xterm}
1438 Older programs such as @command{xterm} do not use Fontconfig and instead
1439 rely on server-side font rendering. Such programs require to specify a
1440 full name of a font using XLFD (X Logical Font Description), like this:
1443 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1446 To be able to use such full names for the TrueType fonts installed in
1447 your Guix profile, you need to extend the font path of the X server:
1450 xset +fp ~/.guix-profile/share/fonts/truetype
1453 @cindex @code{xlsfonts}
1454 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1455 to make sure your TrueType fonts are listed there.
1457 @cindex @code{fc-cache}
1459 After installing fonts you may have to refresh the font cache to use
1460 them in applications. The same applies when applications installed via
1461 Guix do not seem to find fonts. To force rebuilding of the font cache
1462 run @code{fc-cache -f}. The @code{fc-cache} command is provided by the
1463 @code{fontconfig} package.
1465 @subsection X.509 Certificates
1467 @cindex @code{nss-certs}
1468 The @code{nss-certs} package provides X.509 certificates, which allow
1469 programs to authenticate Web servers accessed over HTTPS.
1471 When using Guix on a foreign distro, you can install this package and
1472 define the relevant environment variables so that packages know where to
1473 look for certificates. @xref{X.509 Certificates}, for detailed
1476 @subsection Emacs Packages
1478 @cindex @code{emacs}
1479 When you install Emacs packages with Guix, the elisp files may be placed
1480 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1482 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1483 directory exists because potentially there may exist thousands of Emacs
1484 packages and storing all their files in a single directory may be not
1485 reliable (because of name conflicts). So we think using a separate
1486 directory for each package is a good idea. It is very similar to how
1487 the Emacs package system organizes the file structure (@pxref{Package
1488 Files,,, emacs, The GNU Emacs Manual}).
1490 By default, Emacs (installed with Guix) ``knows'' where these packages
1491 are placed, so you do not need to perform any configuration. If, for
1492 some reason, you want to avoid auto-loading Emacs packages installed
1493 with Guix, you can do so by running Emacs with @code{--no-site-file}
1494 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1496 @subsection The GCC toolchain
1501 Guix offers individual compiler packages such as @code{gcc} but if you
1502 are in need of a complete toolchain for compiling and linking source
1503 code what you really want is the @code{gcc-toolchain} package. This
1504 package provides a complete GCC toolchain for C/C++ development,
1505 including GCC itself, the GNU C Library (headers and binaries, plus
1506 debugging symbols in the @code{debug} output), Binutils, and a linker
1509 @cindex attempt to use impure library, error message
1511 The wrapper's purpose is to inspect the @code{-L} and @code{-l} switches
1512 passed to the linker, add corresponding @code{-rpath} arguments, and
1513 invoke the actual linker with this new set of arguments. By default,
1514 the linker wrapper refuses to link to libraries outside the store to
1515 ensure ``purity''. This can be annoying when using the toolchain to
1516 link with local libraries. To allow references to libraries outside the
1517 store you need to define the environment variable
1518 @code{GUIX_LD_WRAPPER_ALLOW_IMPURITIES}.
1522 @c *********************************************************************
1523 @node Package Management
1524 @chapter Package Management
1527 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1528 remove software packages, without having to know about their build
1529 procedures or dependencies. Guix also goes beyond this obvious set of
1532 This chapter describes the main features of Guix, as well as the
1533 package management tools it provides. Along with the command-line
1534 interface described below (@pxref{Invoking guix package, @code{guix
1535 package}}), you may also use Emacs Interface (@pxref{Top,,,
1536 emacs-guix, The Emacs-Guix Reference Manual}), after installing
1537 @code{emacs-guix} package (run @kbd{M-x guix-help} command to start
1541 guix package -i emacs-guix
1545 * Features:: How Guix will make your life brighter.
1546 * Invoking guix package:: Package installation, removal, etc.
1547 * Substitutes:: Downloading pre-built binaries.
1548 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1549 * Invoking guix gc:: Running the garbage collector.
1550 * Invoking guix pull:: Fetching the latest Guix and distribution.
1551 * Invoking guix pack:: Creating software bundles.
1552 * Invoking guix archive:: Exporting and importing store files.
1558 When using Guix, each package ends up in the @dfn{package store}, in its
1559 own directory---something that resembles
1560 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1562 Instead of referring to these directories, users have their own
1563 @dfn{profile}, which points to the packages that they actually want to
1564 use. These profiles are stored within each user's home directory, at
1565 @code{$HOME/.guix-profile}.
1567 For example, @code{alice} installs GCC 4.7.2. As a result,
1568 @file{/home/alice/.guix-profile/bin/gcc} points to
1569 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1570 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1571 simply continues to point to
1572 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1573 coexist on the same system without any interference.
1575 The @command{guix package} command is the central tool to manage
1576 packages (@pxref{Invoking guix package}). It operates on the per-user
1577 profiles, and can be used @emph{with normal user privileges}.
1579 @cindex transactions
1580 The command provides the obvious install, remove, and upgrade
1581 operations. Each invocation is actually a @emph{transaction}: either
1582 the specified operation succeeds, or nothing happens. Thus, if the
1583 @command{guix package} process is terminated during the transaction,
1584 or if a power outage occurs during the transaction, then the user's
1585 profile remains in its previous state, and remains usable.
1587 In addition, any package transaction may be @emph{rolled back}. So, if,
1588 for example, an upgrade installs a new version of a package that turns
1589 out to have a serious bug, users may roll back to the previous instance
1590 of their profile, which was known to work well. Similarly, the global
1591 system configuration on GuixSD is subject to
1592 transactional upgrades and roll-back
1593 (@pxref{Using the Configuration System}).
1595 All packages in the package store may be @emph{garbage-collected}.
1596 Guix can determine which packages are still referenced by user
1597 profiles, and remove those that are provably no longer referenced
1598 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1599 generations of their profile so that the packages they refer to can be
1602 @cindex reproducibility
1603 @cindex reproducible builds
1604 Finally, Guix takes a @dfn{purely functional} approach to package
1605 management, as described in the introduction (@pxref{Introduction}).
1606 Each @file{/gnu/store} package directory name contains a hash of all the
1607 inputs that were used to build that package---compiler, libraries, build
1608 scripts, etc. This direct correspondence allows users to make sure a
1609 given package installation matches the current state of their
1610 distribution. It also helps maximize @dfn{build reproducibility}:
1611 thanks to the isolated build environments that are used, a given build
1612 is likely to yield bit-identical files when performed on different
1613 machines (@pxref{Invoking guix-daemon, container}).
1616 This foundation allows Guix to support @dfn{transparent binary/source
1617 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1618 available from an external source---a @dfn{substitute}, Guix just
1619 downloads it and unpacks it;
1620 otherwise, it builds the package from source, locally
1621 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1622 reproducible, users do not have to trust servers that provide
1623 substitutes: they can force a local build and @emph{challenge} providers
1624 (@pxref{Invoking guix challenge}).
1626 Control over the build environment is a feature that is also useful for
1627 developers. The @command{guix environment} command allows developers of
1628 a package to quickly set up the right development environment for their
1629 package, without having to manually install the dependencies of the
1630 package into their profile (@pxref{Invoking guix environment}).
1632 @node Invoking guix package
1633 @section Invoking @command{guix package}
1635 @cindex installing packages
1636 @cindex removing packages
1637 @cindex package installation
1638 @cindex package removal
1639 The @command{guix package} command is the tool that allows users to
1640 install, upgrade, and remove packages, as well as rolling back to
1641 previous configurations. It operates only on the user's own profile,
1642 and works with normal user privileges (@pxref{Features}). Its syntax
1646 guix package @var{options}
1648 @cindex transactions
1649 Primarily, @var{options} specifies the operations to be performed during
1650 the transaction. Upon completion, a new profile is created, but
1651 previous @dfn{generations} of the profile remain available, should the user
1654 For example, to remove @code{lua} and install @code{guile} and
1655 @code{guile-cairo} in a single transaction:
1658 guix package -r lua -i guile guile-cairo
1661 @command{guix package} also supports a @dfn{declarative approach}
1662 whereby the user specifies the exact set of packages to be available and
1663 passes it @i{via} the @option{--manifest} option
1664 (@pxref{profile-manifest, @option{--manifest}}).
1667 For each user, a symlink to the user's default profile is automatically
1668 created in @file{$HOME/.guix-profile}. This symlink always points to the
1669 current generation of the user's default profile. Thus, users can add
1670 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1671 variable, and so on.
1672 @cindex search paths
1673 If you are not using the Guix System Distribution, consider adding the
1674 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1675 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1676 shells get all the right environment variable definitions:
1679 GUIX_PROFILE="$HOME/.guix-profile" \
1680 source "$HOME/.guix-profile/etc/profile"
1683 In a multi-user setup, user profiles are stored in a place registered as
1684 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1685 to (@pxref{Invoking guix gc}). That directory is normally
1686 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1687 @var{localstatedir} is the value passed to @code{configure} as
1688 @code{--localstatedir}, and @var{user} is the user name. The
1689 @file{per-user} directory is created when @command{guix-daemon} is
1690 started, and the @var{user} sub-directory is created by @command{guix
1693 The @var{options} can be among the following:
1697 @item --install=@var{package} @dots{}
1698 @itemx -i @var{package} @dots{}
1699 Install the specified @var{package}s.
1701 Each @var{package} may specify either a simple package name, such as
1702 @code{guile}, or a package name followed by an at-sign and version number,
1703 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1704 case, the newest version prefixed by @code{1.8} is selected.)
1706 If no version number is specified, the
1707 newest available version will be selected. In addition, @var{package}
1708 may contain a colon, followed by the name of one of the outputs of the
1709 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1710 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1711 name (and optionally version) are searched for among the GNU
1712 distribution modules (@pxref{Package Modules}).
1714 @cindex propagated inputs
1715 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1716 that automatically get installed along with the required package
1717 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1718 @code{package} objects}, for information about propagated inputs in
1719 package definitions).
1721 @anchor{package-cmd-propagated-inputs}
1722 An example is the GNU MPC library: its C header files refer to those of
1723 the GNU MPFR library, which in turn refer to those of the GMP library.
1724 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1725 in the profile; removing MPC also removes MPFR and GMP---unless they had
1726 also been explicitly installed by the user.
1728 Besides, packages sometimes rely on the definition of environment
1729 variables for their search paths (see explanation of
1730 @code{--search-paths} below). Any missing or possibly incorrect
1731 environment variable definitions are reported here.
1733 @item --install-from-expression=@var{exp}
1735 Install the package @var{exp} evaluates to.
1737 @var{exp} must be a Scheme expression that evaluates to a
1738 @code{<package>} object. This option is notably useful to disambiguate
1739 between same-named variants of a package, with expressions such as
1740 @code{(@@ (gnu packages base) guile-final)}.
1742 Note that this option installs the first output of the specified
1743 package, which may be insufficient when needing a specific output of a
1744 multiple-output package.
1746 @item --install-from-file=@var{file}
1747 @itemx -f @var{file}
1748 Install the package that the code within @var{file} evaluates to.
1750 As an example, @var{file} might contain a definition like this
1751 (@pxref{Defining Packages}):
1754 @verbatiminclude package-hello.scm
1757 Developers may find it useful to include such a @file{guix.scm} file
1758 in the root of their project source tree that can be used to test
1759 development snapshots and create reproducible development environments
1760 (@pxref{Invoking guix environment}).
1762 @item --remove=@var{package} @dots{}
1763 @itemx -r @var{package} @dots{}
1764 Remove the specified @var{package}s.
1766 As for @code{--install}, each @var{package} may specify a version number
1767 and/or output name in addition to the package name. For instance,
1768 @code{-r glibc:debug} would remove the @code{debug} output of
1771 @item --upgrade[=@var{regexp} @dots{}]
1772 @itemx -u [@var{regexp} @dots{}]
1773 @cindex upgrading packages
1774 Upgrade all the installed packages. If one or more @var{regexp}s are
1775 specified, upgrade only installed packages whose name matches a
1776 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1778 Note that this upgrades package to the latest version of packages found
1779 in the distribution currently installed. To update your distribution,
1780 you should regularly run @command{guix pull} (@pxref{Invoking guix
1783 @item --do-not-upgrade[=@var{regexp} @dots{}]
1784 When used together with the @code{--upgrade} option, do @emph{not}
1785 upgrade any packages whose name matches a @var{regexp}. For example, to
1786 upgrade all packages in the current profile except those containing the
1787 substring ``emacs'':
1790 $ guix package --upgrade . --do-not-upgrade emacs
1793 @item @anchor{profile-manifest}--manifest=@var{file}
1794 @itemx -m @var{file}
1795 @cindex profile declaration
1796 @cindex profile manifest
1797 Create a new generation of the profile from the manifest object
1798 returned by the Scheme code in @var{file}.
1800 This allows you to @emph{declare} the profile's contents rather than
1801 constructing it through a sequence of @code{--install} and similar
1802 commands. The advantage is that @var{file} can be put under version
1803 control, copied to different machines to reproduce the same profile, and
1806 @c FIXME: Add reference to (guix profile) documentation when available.
1807 @var{file} must return a @dfn{manifest} object, which is roughly a list
1810 @findex packages->manifest
1812 (use-package-modules guile emacs)
1817 ;; Use a specific package output.
1818 (list guile-2.0 "debug")))
1821 @findex specifications->manifest
1822 In this example we have to know which modules define the @code{emacs}
1823 and @code{guile-2.0} variables to provide the right
1824 @code{use-package-modules} line, which can be cumbersome. We can
1825 instead provide regular package specifications and let
1826 @code{specifications->manifest} look up the corresponding package
1830 (specifications->manifest
1831 '("emacs" "guile@@2.2" "guile@@2.2:debug"))
1835 @cindex rolling back
1836 @cindex undoing transactions
1837 @cindex transactions, undoing
1838 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1839 the last transaction.
1841 When combined with options such as @code{--install}, roll back occurs
1842 before any other actions.
1844 When rolling back from the first generation that actually contains
1845 installed packages, the profile is made to point to the @dfn{zeroth
1846 generation}, which contains no files apart from its own metadata.
1848 After having rolled back, installing, removing, or upgrading packages
1849 overwrites previous future generations. Thus, the history of the
1850 generations in a profile is always linear.
1852 @item --switch-generation=@var{pattern}
1853 @itemx -S @var{pattern}
1855 Switch to a particular generation defined by @var{pattern}.
1857 @var{pattern} may be either a generation number or a number prefixed
1858 with ``+'' or ``-''. The latter means: move forward/backward by a
1859 specified number of generations. For example, if you want to return to
1860 the latest generation after @code{--roll-back}, use
1861 @code{--switch-generation=+1}.
1863 The difference between @code{--roll-back} and
1864 @code{--switch-generation=-1} is that @code{--switch-generation} will
1865 not make a zeroth generation, so if a specified generation does not
1866 exist, the current generation will not be changed.
1868 @item --search-paths[=@var{kind}]
1869 @cindex search paths
1870 Report environment variable definitions, in Bash syntax, that may be
1871 needed in order to use the set of installed packages. These environment
1872 variables are used to specify @dfn{search paths} for files used by some
1873 of the installed packages.
1875 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1876 environment variables to be defined so it can look for headers and
1877 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1878 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1879 library are installed in the profile, then @code{--search-paths} will
1880 suggest setting these variables to @code{@var{profile}/include} and
1881 @code{@var{profile}/lib}, respectively.
1883 The typical use case is to define these environment variables in the
1887 $ eval `guix package --search-paths`
1890 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1891 meaning that the returned environment variable definitions will either
1892 be exact settings, or prefixes or suffixes of the current value of these
1893 variables. When omitted, @var{kind} defaults to @code{exact}.
1895 This option can also be used to compute the @emph{combined} search paths
1896 of several profiles. Consider this example:
1899 $ guix package -p foo -i guile
1900 $ guix package -p bar -i guile-json
1901 $ guix package -p foo -p bar --search-paths
1904 The last command above reports about the @code{GUILE_LOAD_PATH}
1905 variable, even though, taken individually, neither @file{foo} nor
1906 @file{bar} would lead to that recommendation.
1909 @item --profile=@var{profile}
1910 @itemx -p @var{profile}
1911 Use @var{profile} instead of the user's default profile.
1914 Produce verbose output. In particular, emit the build log of the
1915 environment on the standard error port.
1918 Use the bootstrap Guile to build the profile. This option is only
1919 useful to distribution developers.
1923 In addition to these actions, @command{guix package} supports the
1924 following options to query the current state of a profile, or the
1925 availability of packages:
1929 @item --search=@var{regexp}
1930 @itemx -s @var{regexp}
1931 @cindex searching for packages
1932 List the available packages whose name, synopsis, or description matches
1933 @var{regexp}, sorted by relevance. Print all the metadata of matching packages in
1934 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1935 GNU recutils manual}).
1937 This allows specific fields to be extracted using the @command{recsel}
1938 command, for instance:
1941 $ guix package -s malloc | recsel -p name,version,relevance
1955 Similarly, to show the name of all the packages available under the
1956 terms of the GNU@tie{}LGPL version 3:
1959 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1966 It is also possible to refine search results using several @code{-s}
1967 flags. For example, the following command returns a list of board
1971 $ guix package -s '\<board\>' -s game | recsel -p name
1976 If we were to omit @code{-s game}, we would also get software packages
1977 that deal with printed circuit boards; removing the angle brackets
1978 around @code{board} would further add packages that have to do with
1981 And now for a more elaborate example. The following command searches
1982 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1983 libraries, and prints the name and synopsis of the matching packages:
1986 $ guix package -s crypto -s library | \
1987 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1991 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1992 information on @dfn{selection expressions} for @code{recsel -e}.
1994 @item --show=@var{package}
1995 Show details about @var{package}, taken from the list of available packages, in
1996 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
2000 $ guix package --show=python | recsel -p name,version
2008 You may also specify the full name of a package to only get details about a
2009 specific version of it:
2011 $ guix package --show=python@@3.4 | recsel -p name,version
2018 @item --list-installed[=@var{regexp}]
2019 @itemx -I [@var{regexp}]
2020 List the currently installed packages in the specified profile, with the
2021 most recently installed packages shown last. When @var{regexp} is
2022 specified, list only installed packages whose name matches @var{regexp}.
2024 For each installed package, print the following items, separated by
2025 tabs: the package name, its version string, the part of the package that
2026 is installed (for instance, @code{out} for the default output,
2027 @code{include} for its headers, etc.), and the path of this package in
2030 @item --list-available[=@var{regexp}]
2031 @itemx -A [@var{regexp}]
2032 List packages currently available in the distribution for this system
2033 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
2034 installed packages whose name matches @var{regexp}.
2036 For each package, print the following items separated by tabs: its name,
2037 its version string, the parts of the package (@pxref{Packages with
2038 Multiple Outputs}), and the source location of its definition.
2040 @item --list-generations[=@var{pattern}]
2041 @itemx -l [@var{pattern}]
2043 Return a list of generations along with their creation dates; for each
2044 generation, show the installed packages, with the most recently
2045 installed packages shown last. Note that the zeroth generation is never
2048 For each installed package, print the following items, separated by
2049 tabs: the name of a package, its version string, the part of the package
2050 that is installed (@pxref{Packages with Multiple Outputs}), and the
2051 location of this package in the store.
2053 When @var{pattern} is used, the command returns only matching
2054 generations. Valid patterns include:
2057 @item @emph{Integers and comma-separated integers}. Both patterns denote
2058 generation numbers. For instance, @code{--list-generations=1} returns
2061 And @code{--list-generations=1,8,2} outputs three generations in the
2062 specified order. Neither spaces nor trailing commas are allowed.
2064 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
2065 specified generations and everything in between. Note that the start of
2066 a range must be smaller than its end.
2068 It is also possible to omit the endpoint. For example,
2069 @code{--list-generations=2..}, returns all generations starting from the
2072 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
2073 or months by passing an integer along with the first letter of the
2074 duration. For example, @code{--list-generations=20d} lists generations
2075 that are up to 20 days old.
2078 @item --delete-generations[=@var{pattern}]
2079 @itemx -d [@var{pattern}]
2080 When @var{pattern} is omitted, delete all generations except the current
2083 This command accepts the same patterns as @option{--list-generations}.
2084 When @var{pattern} is specified, delete the matching generations. When
2085 @var{pattern} specifies a duration, generations @emph{older} than the
2086 specified duration match. For instance, @code{--delete-generations=1m}
2087 deletes generations that are more than one month old.
2089 If the current generation matches, it is @emph{not} deleted. Also, the
2090 zeroth generation is never deleted.
2092 Note that deleting generations prevents rolling back to them.
2093 Consequently, this command must be used with care.
2097 Finally, since @command{guix package} may actually start build
2098 processes, it supports all the common build options (@pxref{Common Build
2099 Options}). It also supports package transformation options, such as
2100 @option{--with-source} (@pxref{Package Transformation Options}).
2101 However, note that package transformations are lost when upgrading; to
2102 preserve transformations across upgrades, you should define your own
2103 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
2104 (@pxref{Defining Packages}).
2108 @section Substitutes
2111 @cindex pre-built binaries
2112 Guix supports transparent source/binary deployment, which means that it
2113 can either build things locally, or download pre-built items from a
2114 server. We call these pre-built items @dfn{substitutes}---they are
2115 substitutes for local build results. In many cases, downloading a
2116 substitute is much faster than building things locally.
2118 Substitutes can be anything resulting from a derivation build
2119 (@pxref{Derivations}). Of course, in the common case, they are
2120 pre-built package binaries, but source tarballs, for instance, which
2121 also result from derivation builds, can be available as substitutes.
2123 The @code{hydra.gnu.org} server is a front-end to a build farm that
2124 builds packages from the GNU distribution continuously for some
2125 architectures, and makes them available as substitutes. This is the
2126 default source of substitutes; it can be overridden by passing the
2127 @option{--substitute-urls} option either to @command{guix-daemon}
2128 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2129 or to client tools such as @command{guix package}
2130 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2133 Substitute URLs can be either HTTP or HTTPS.
2134 HTTPS is recommended because communications are encrypted; conversely,
2135 using HTTP makes all communications visible to an eavesdropper, who
2136 could use the information gathered to determine, for instance, whether
2137 your system has unpatched security vulnerabilities.
2140 @cindex digital signatures
2141 @cindex substitutes, authorization thereof
2142 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2144 must add its public key to the access control list (ACL) of archive
2145 imports, using the @command{guix archive} command (@pxref{Invoking guix
2146 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2147 be compromised and to serve genuine substitutes.
2149 This public key is installed along with Guix, in
2150 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2151 the installation prefix of Guix. If you installed Guix from source,
2152 make sure you checked the GPG signature of
2153 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2154 Then, you can run something like this:
2157 # guix archive --authorize < hydra.gnu.org.pub
2160 Once this is in place, the output of a command like @code{guix build}
2161 should change from something like:
2164 $ guix build emacs --dry-run
2165 The following derivations would be built:
2166 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2167 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2168 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2169 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2177 $ guix build emacs --dry-run
2178 The following files would be downloaded:
2179 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2180 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2181 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2182 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2187 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2188 will be downloaded, when possible, for future builds.
2190 Guix ignores substitutes that are not signed, or that are not signed by
2191 one of the keys listed in the ACL. It also detects and raises an error
2192 when attempting to use a substitute that has been tampered with.
2195 Substitutes are downloaded over HTTP or HTTPS.
2196 The @code{http_proxy} environment
2197 variable can be set in the environment of @command{guix-daemon} and is
2198 honored for downloads of substitutes. Note that the value of
2199 @code{http_proxy} in the environment where @command{guix build},
2200 @command{guix package}, and other client commands are run has
2201 @emph{absolutely no effect}.
2203 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2204 (in other words, the server is not authenticated), contrary to what
2205 HTTPS clients such as Web browsers usually do. This is because Guix
2206 authenticates substitute information itself, as explained above, which
2207 is what we care about (whereas X.509 certificates are about
2208 authenticating bindings between domain names and public keys.)
2210 You can get statistics on the substitutes provided by a server using the
2211 @command{guix weather} command (@pxref{Invoking guix weather}).
2213 The substitute mechanism can be disabled globally by running
2214 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2215 guix-daemon}). It can also be disabled temporarily by passing the
2216 @code{--no-substitutes} option to @command{guix package}, @command{guix
2217 build}, and other command-line tools.
2220 @unnumberedsubsec On Trusting Binaries
2222 Today, each individual's control over their own computing is at the
2223 mercy of institutions, corporations, and groups with enough power and
2224 determination to subvert the computing infrastructure and exploit its
2225 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2226 convenient, we encourage users to also build on their own, or even run
2227 their own build farm, such that @code{hydra.gnu.org} is less of an
2228 interesting target. One way to help is by publishing the software you
2229 build using @command{guix publish} so that others have one more choice
2230 of server to download substitutes from (@pxref{Invoking guix publish}).
2232 Guix has the foundations to maximize build reproducibility
2233 (@pxref{Features}). In most cases, independent builds of a given
2234 package or derivation should yield bit-identical results. Thus, through
2235 a diverse set of independent package builds, we can strengthen the
2236 integrity of our systems. The @command{guix challenge} command aims to
2237 help users assess substitute servers, and to assist developers in
2238 finding out about non-deterministic package builds (@pxref{Invoking guix
2239 challenge}). Similarly, the @option{--check} option of @command{guix
2240 build} allows users to check whether previously-installed substitutes
2241 are genuine by rebuilding them locally (@pxref{build-check,
2242 @command{guix build --check}}).
2244 In the future, we want Guix to have support to publish and retrieve
2245 binaries to/from other users, in a peer-to-peer fashion. If you would
2246 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2249 @node Packages with Multiple Outputs
2250 @section Packages with Multiple Outputs
2252 @cindex multiple-output packages
2253 @cindex package outputs
2256 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2257 source package leads to exactly one directory in the store. When running
2258 @command{guix package -i glibc}, one installs the default output of the
2259 GNU libc package; the default output is called @code{out}, but its name
2260 can be omitted as shown in this command. In this particular case, the
2261 default output of @code{glibc} contains all the C header files, shared
2262 libraries, static libraries, Info documentation, and other supporting
2265 Sometimes it is more appropriate to separate the various types of files
2266 produced from a single source package into separate outputs. For
2267 instance, the GLib C library (used by GTK+ and related packages)
2268 installs more than 20 MiB of reference documentation as HTML pages.
2269 To save space for users who do not need it, the documentation goes to a
2270 separate output, called @code{doc}. To install the main GLib output,
2271 which contains everything but the documentation, one would run:
2274 guix package -i glib
2277 @cindex documentation
2278 The command to install its documentation is:
2281 guix package -i glib:doc
2284 Some packages install programs with different ``dependency footprints''.
2285 For instance, the WordNet package installs both command-line tools and
2286 graphical user interfaces (GUIs). The former depend solely on the C
2287 library, whereas the latter depend on Tcl/Tk and the underlying X
2288 libraries. In this case, we leave the command-line tools in the default
2289 output, whereas the GUIs are in a separate output. This allows users
2290 who do not need the GUIs to save space. The @command{guix size} command
2291 can help find out about such situations (@pxref{Invoking guix size}).
2292 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2294 There are several such multiple-output packages in the GNU distribution.
2295 Other conventional output names include @code{lib} for libraries and
2296 possibly header files, @code{bin} for stand-alone programs, and
2297 @code{debug} for debugging information (@pxref{Installing Debugging
2298 Files}). The outputs of a packages are listed in the third column of
2299 the output of @command{guix package --list-available} (@pxref{Invoking
2303 @node Invoking guix gc
2304 @section Invoking @command{guix gc}
2306 @cindex garbage collector
2308 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2309 The @command{guix gc} command allows users to explicitly run the garbage
2310 collector to reclaim space from the @file{/gnu/store} directory. It is
2311 the @emph{only} way to remove files from @file{/gnu/store}---removing
2312 files or directories manually may break it beyond repair!
2314 The garbage collector has a set of known @dfn{roots}: any file under
2315 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2316 cannot be deleted; any other file is considered @dfn{dead} and may be
2317 deleted. The set of garbage collector roots includes default user
2318 profiles, and may be augmented with @command{guix build --root}, for
2319 example (@pxref{Invoking guix build}).
2321 Prior to running @code{guix gc --collect-garbage} to make space, it is
2322 often useful to remove old generations from user profiles; that way, old
2323 package builds referenced by those generations can be reclaimed. This
2324 is achieved by running @code{guix package --delete-generations}
2325 (@pxref{Invoking guix package}).
2327 Our recommendation is to run a garbage collection periodically, or when
2328 you are short on disk space. For instance, to guarantee that at least
2329 5@tie{}GB are available on your disk, simply run:
2335 It is perfectly safe to run as a non-interactive periodic job
2336 (@pxref{Scheduled Job Execution}, for how to set up such a job on
2337 GuixSD). Running @command{guix gc} with no arguments will collect as
2338 much garbage as it can, but that is often inconvenient: you may find
2339 yourself having to rebuild or re-download software that is ``dead'' from
2340 the GC viewpoint but that is necessary to build other pieces of
2341 software---e.g., the compiler tool chain.
2343 The @command{guix gc} command has three modes of operation: it can be
2344 used to garbage-collect any dead files (the default), to delete specific
2345 files (the @code{--delete} option), to print garbage-collector
2346 information, or for more advanced queries. The garbage collection
2347 options are as follows:
2350 @item --collect-garbage[=@var{min}]
2351 @itemx -C [@var{min}]
2352 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2353 sub-directories. This is the default operation when no option is
2356 When @var{min} is given, stop once @var{min} bytes have been collected.
2357 @var{min} may be a number of bytes, or it may include a unit as a
2358 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2359 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2361 When @var{min} is omitted, collect all the garbage.
2363 @item --free-space=@var{free}
2364 @itemx -F @var{free}
2365 Collect garbage until @var{free} space is available under
2366 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2367 as @code{500MiB}, as described above.
2369 When @var{free} or more is already available in @file{/gnu/store}, do
2370 nothing and exit immediately.
2374 Attempt to delete all the store files and directories specified as
2375 arguments. This fails if some of the files are not in the store, or if
2376 they are still live.
2378 @item --list-failures
2379 List store items corresponding to cached build failures.
2381 This prints nothing unless the daemon was started with
2382 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2383 @option{--cache-failures}}).
2385 @item --clear-failures
2386 Remove the specified store items from the failed-build cache.
2388 Again, this option only makes sense when the daemon is started with
2389 @option{--cache-failures}. Otherwise, it does nothing.
2392 Show the list of dead files and directories still present in the
2393 store---i.e., files and directories no longer reachable from any root.
2396 Show the list of live store files and directories.
2400 In addition, the references among existing store files can be queried:
2406 @cindex package dependencies
2407 List the references (respectively, the referrers) of store files given
2413 List the requisites of the store files passed as arguments. Requisites
2414 include the store files themselves, their references, and the references
2415 of these, recursively. In other words, the returned list is the
2416 @dfn{transitive closure} of the store files.
2418 @xref{Invoking guix size}, for a tool to profile the size of the closure
2419 of an element. @xref{Invoking guix graph}, for a tool to visualize
2420 the graph of references.
2424 Lastly, the following options allow you to check the integrity of the
2425 store and to control disk usage.
2429 @item --verify[=@var{options}]
2430 @cindex integrity, of the store
2431 @cindex integrity checking
2432 Verify the integrity of the store.
2434 By default, make sure that all the store items marked as valid in the
2435 database of the daemon actually exist in @file{/gnu/store}.
2437 When provided, @var{options} must be a comma-separated list containing one
2438 or more of @code{contents} and @code{repair}.
2440 When passing @option{--verify=contents}, the daemon computes the
2441 content hash of each store item and compares it against its hash in the
2442 database. Hash mismatches are reported as data corruptions. Because it
2443 traverses @emph{all the files in the store}, this command can take a
2444 long time, especially on systems with a slow disk drive.
2446 @cindex repairing the store
2447 @cindex corruption, recovering from
2448 Using @option{--verify=repair} or @option{--verify=contents,repair}
2449 causes the daemon to try to repair corrupt store items by fetching
2450 substitutes for them (@pxref{Substitutes}). Because repairing is not
2451 atomic, and thus potentially dangerous, it is available only to the
2452 system administrator. A lightweight alternative, when you know exactly
2453 which items in the store are corrupt, is @command{guix build --repair}
2454 (@pxref{Invoking guix build}).
2457 @cindex deduplication
2458 Optimize the store by hard-linking identical files---this is
2459 @dfn{deduplication}.
2461 The daemon performs deduplication after each successful build or archive
2462 import, unless it was started with @code{--disable-deduplication}
2463 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2464 this option is primarily useful when the daemon was running with
2465 @code{--disable-deduplication}.
2469 @node Invoking guix pull
2470 @section Invoking @command{guix pull}
2472 @cindex upgrading Guix
2473 @cindex updating Guix
2474 @cindex @command{guix pull}
2476 Packages are installed or upgraded to the latest version available in
2477 the distribution currently available on your local machine. To update
2478 that distribution, along with the Guix tools, you must run @command{guix
2479 pull}: the command downloads the latest Guix source code and package
2480 descriptions, and deploys it. Source code is downloaded from a
2481 @uref{https://git-scm.com, Git} repository.
2483 On completion, @command{guix package} will use packages and package
2484 versions from this just-retrieved copy of Guix. Not only that, but all
2485 the Guix commands and Scheme modules will also be taken from that latest
2486 version. New @command{guix} sub-commands added by the update also
2489 Any user can update their Guix copy using @command{guix pull}, and the
2490 effect is limited to the user who run @command{guix pull}. For
2491 instance, when user @code{root} runs @command{guix pull}, this has no
2492 effect on the version of Guix that user @code{alice} sees, and vice
2493 versa@footnote{Under the hood, @command{guix pull} updates the
2494 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2495 and the @command{guix} command loads code from there. Currently, the
2496 only way to roll back an invocation of @command{guix pull} is to
2497 manually update this symlink to point to the previous Guix.}.
2499 The @command{guix pull} command is usually invoked with no arguments,
2500 but it supports the following options:
2504 Produce verbose output, writing build logs to the standard error output.
2506 @item --url=@var{url}
2507 Download Guix from the Git repository at @var{url}.
2509 By default, the source is taken from its canonical Git repository at
2510 @code{gnu.org}, for the stable branch of Guix.
2512 @item --commit=@var{commit}
2513 Deploy @var{commit}, a valid Git commit ID represented as a hexadecimal
2516 @item --branch=@var{branch}
2517 Deploy the tip of @var{branch}, the name of a Git branch available on
2518 the repository at @var{url}.
2521 Use the bootstrap Guile to build the latest Guix. This option is only
2522 useful to Guix developers.
2525 In addition, @command{guix pull} supports all the common build options
2526 (@pxref{Common Build Options}).
2528 @node Invoking guix pack
2529 @section Invoking @command{guix pack}
2531 Occasionally you want to pass software to people who are not (yet!)
2532 lucky enough to be using Guix. You'd tell them to run @command{guix
2533 package -i @var{something}}, but that's not possible in this case. This
2534 is where @command{guix pack} comes in.
2538 @cindex application bundle
2539 @cindex software bundle
2540 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2541 @dfn{software bundle}: it creates a tarball or some other archive
2542 containing the binaries of the software you're interested in, and all
2543 its dependencies. The resulting archive can be used on any machine that
2544 does not have Guix, and people can run the exact same binaries as those
2545 you have with Guix. The pack itself is created in a bit-reproducible
2546 fashion, so anyone can verify that it really contains the build results
2547 that you pretend to be shipping.
2549 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2550 their dependencies, you can run:
2553 $ guix pack guile emacs geiser
2555 /gnu/store/@dots{}-pack.tar.gz
2558 The result here is a tarball containing a @file{/gnu/store} directory
2559 with all the relevant packages. The resulting tarball contains a
2560 @dfn{profile} with the three packages of interest; the profile is the
2561 same as would be created by @command{guix package -i}. It is this
2562 mechanism that is used to create Guix's own standalone binary tarball
2563 (@pxref{Binary Installation}).
2565 Users of this pack would have to run
2566 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2567 find inconvenient. To work around it, you can create, say, a
2568 @file{/opt/gnu/bin} symlink to the profile:
2571 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2575 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2577 Alternatively, you can produce a pack in the Docker image format using
2578 the following command:
2581 guix pack -f docker guile emacs geiser
2585 The result is a tarball that can be passed to the @command{docker load}
2587 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2588 documentation} for more information.
2590 Several command-line options allow you to customize your pack:
2593 @item --format=@var{format}
2594 @itemx -f @var{format}
2595 Produce a pack in the given @var{format}.
2597 The available formats are:
2601 This is the default format. It produces a tarball containing all the
2602 specified binaries and symlinks.
2605 This produces a tarball that follows the
2606 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2607 Docker Image Specification}.
2610 @item --expression=@var{expr}
2611 @itemx -e @var{expr}
2612 Consider the package @var{expr} evaluates to.
2614 This has the same purpose as the same-named option in @command{guix
2615 build} (@pxref{Additional Build Options, @code{--expression} in
2616 @command{guix build}}).
2618 @item --system=@var{system}
2619 @itemx -s @var{system}
2620 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2621 the system type of the build host.
2623 @item --target=@var{triplet}
2624 @cindex cross-compilation
2625 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2626 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2627 configuration triplets,, autoconf, Autoconf}).
2629 @item --compression=@var{tool}
2630 @itemx -C @var{tool}
2631 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2632 @code{bzip2}, @code{xz}, or @code{lzip}.
2634 @item --symlink=@var{spec}
2635 @itemx -S @var{spec}
2636 Add the symlinks specified by @var{spec} to the pack. This option can
2637 appear several times.
2639 @var{spec} has the form @code{@var{source}=@var{target}}, where
2640 @var{source} is the symlink that will be created and @var{target} is the
2643 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2644 symlink pointing to the @file{bin} sub-directory of the profile.
2646 @item --localstatedir
2647 Include the ``local state directory'', @file{/var/guix}, in the
2650 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2651 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2652 the pack means that the store is ``complete'' and manageable by Guix;
2653 not providing it pack means that the store is ``dead'': items cannot be
2654 added to it or removed from it after extraction of the pack.
2656 One use case for this is the Guix self-contained binary tarball
2657 (@pxref{Binary Installation}).
2660 In addition, @command{guix pack} supports all the common build options
2661 (@pxref{Common Build Options}) and all the package transformation
2662 options (@pxref{Package Transformation Options}).
2665 @node Invoking guix archive
2666 @section Invoking @command{guix archive}
2668 @cindex @command{guix archive}
2670 The @command{guix archive} command allows users to @dfn{export} files
2671 from the store into a single archive, and to later @dfn{import} them.
2672 In particular, it allows store files to be transferred from one machine
2673 to the store on another machine.
2675 @cindex exporting store items
2676 To export store files as an archive to standard output, run:
2679 guix archive --export @var{options} @var{specifications}...
2682 @var{specifications} may be either store file names or package
2683 specifications, as for @command{guix package} (@pxref{Invoking guix
2684 package}). For instance, the following command creates an archive
2685 containing the @code{gui} output of the @code{git} package and the main
2686 output of @code{emacs}:
2689 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2692 If the specified packages are not built yet, @command{guix archive}
2693 automatically builds them. The build process may be controlled with the
2694 common build options (@pxref{Common Build Options}).
2696 To transfer the @code{emacs} package to a machine connected over SSH,
2700 guix archive --export -r emacs | ssh the-machine guix archive --import
2704 Similarly, a complete user profile may be transferred from one machine
2705 to another like this:
2708 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2709 ssh the-machine guix-archive --import
2713 However, note that, in both examples, all of @code{emacs} and the
2714 profile as well as all of their dependencies are transferred (due to
2715 @code{-r}), regardless of what is already available in the store on the
2716 target machine. The @code{--missing} option can help figure out which
2717 items are missing from the target store. The @command{guix copy}
2718 command simplifies and optimizes this whole process, so this is probably
2719 what you should use in this case (@pxref{Invoking guix copy}).
2721 @cindex nar, archive format
2722 @cindex normalized archive (nar)
2723 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2724 comparable in spirit to `tar', but with differences
2725 that make it more appropriate for our purposes. First, rather than
2726 recording all Unix metadata for each file, the nar format only mentions
2727 the file type (regular, directory, or symbolic link); Unix permissions
2728 and owner/group are dismissed. Second, the order in which directory
2729 entries are stored always follows the order of file names according to
2730 the C locale collation order. This makes archive production fully
2733 When exporting, the daemon digitally signs the contents of the archive,
2734 and that digital signature is appended. When importing, the daemon
2735 verifies the signature and rejects the import in case of an invalid
2736 signature or if the signing key is not authorized.
2737 @c FIXME: Add xref to daemon doc about signatures.
2739 The main options are:
2743 Export the specified store files or packages (see below.) Write the
2744 resulting archive to the standard output.
2746 Dependencies are @emph{not} included in the output, unless
2747 @code{--recursive} is passed.
2751 When combined with @code{--export}, this instructs @command{guix
2752 archive} to include dependencies of the given items in the archive.
2753 Thus, the resulting archive is self-contained: it contains the closure
2754 of the exported store items.
2757 Read an archive from the standard input, and import the files listed
2758 therein into the store. Abort if the archive has an invalid digital
2759 signature, or if it is signed by a public key not among the authorized
2760 keys (see @code{--authorize} below.)
2763 Read a list of store file names from the standard input, one per line,
2764 and write on the standard output the subset of these files missing from
2767 @item --generate-key[=@var{parameters}]
2768 @cindex signing, archives
2769 Generate a new key pair for the daemon. This is a prerequisite before
2770 archives can be exported with @code{--export}. Note that this operation
2771 usually takes time, because it needs to gather enough entropy to
2772 generate the key pair.
2774 The generated key pair is typically stored under @file{/etc/guix}, in
2775 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2776 key, which must be kept secret.) When @var{parameters} is omitted,
2777 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2778 versions before 1.6.0, it is a 4096-bit RSA key.
2779 Alternatively, @var{parameters} can specify
2780 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2781 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2782 Libgcrypt Reference Manual}).
2785 @cindex authorizing, archives
2786 Authorize imports signed by the public key passed on standard input.
2787 The public key must be in ``s-expression advanced format''---i.e., the
2788 same format as the @file{signing-key.pub} file.
2790 The list of authorized keys is kept in the human-editable file
2791 @file{/etc/guix/acl}. The file contains
2792 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2793 s-expressions''} and is structured as an access-control list in the
2794 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2797 @item --extract=@var{directory}
2798 @itemx -x @var{directory}
2799 Read a single-item archive as served by substitute servers
2800 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2801 low-level operation needed in only very narrow use cases; see below.
2803 For example, the following command extracts the substitute for Emacs
2804 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2808 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2809 | bunzip2 | guix archive -x /tmp/emacs
2812 Single-item archives are different from multiple-item archives produced
2813 by @command{guix archive --export}; they contain a single store item,
2814 and they do @emph{not} embed a signature. Thus this operation does
2815 @emph{no} signature verification and its output should be considered
2818 The primary purpose of this operation is to facilitate inspection of
2819 archive contents coming from possibly untrusted substitute servers.
2823 @c *********************************************************************
2824 @node Programming Interface
2825 @chapter Programming Interface
2827 GNU Guix provides several Scheme programming interfaces (APIs) to
2828 define, build, and query packages. The first interface allows users to
2829 write high-level package definitions. These definitions refer to
2830 familiar packaging concepts, such as the name and version of a package,
2831 its build system, and its dependencies. These definitions can then be
2832 turned into concrete build actions.
2834 Build actions are performed by the Guix daemon, on behalf of users. In a
2835 standard setup, the daemon has write access to the store---the
2836 @file{/gnu/store} directory---whereas users do not. The recommended
2837 setup also has the daemon perform builds in chroots, under a specific
2838 build users, to minimize interference with the rest of the system.
2841 Lower-level APIs are available to interact with the daemon and the
2842 store. To instruct the daemon to perform a build action, users actually
2843 provide it with a @dfn{derivation}. A derivation is a low-level
2844 representation of the build actions to be taken, and the environment in
2845 which they should occur---derivations are to package definitions what
2846 assembly is to C programs. The term ``derivation'' comes from the fact
2847 that build results @emph{derive} from them.
2849 This chapter describes all these APIs in turn, starting from high-level
2850 package definitions.
2853 * Defining Packages:: Defining new packages.
2854 * Build Systems:: Specifying how packages are built.
2855 * The Store:: Manipulating the package store.
2856 * Derivations:: Low-level interface to package derivations.
2857 * The Store Monad:: Purely functional interface to the store.
2858 * G-Expressions:: Manipulating build expressions.
2861 @node Defining Packages
2862 @section Defining Packages
2864 The high-level interface to package definitions is implemented in the
2865 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2866 example, the package definition, or @dfn{recipe}, for the GNU Hello
2867 package looks like this:
2870 (define-module (gnu packages hello)
2871 #:use-module (guix packages)
2872 #:use-module (guix download)
2873 #:use-module (guix build-system gnu)
2874 #:use-module (guix licenses)
2875 #:use-module (gnu packages gawk))
2877 (define-public hello
2883 (uri (string-append "mirror://gnu/hello/hello-" version
2887 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2888 (build-system gnu-build-system)
2889 (arguments '(#:configure-flags '("--enable-silent-rules")))
2890 (inputs `(("gawk" ,gawk)))
2891 (synopsis "Hello, GNU world: An example GNU package")
2892 (description "Guess what GNU Hello prints!")
2893 (home-page "http://www.gnu.org/software/hello/")
2898 Without being a Scheme expert, the reader may have guessed the meaning
2899 of the various fields here. This expression binds the variable
2900 @code{hello} to a @code{<package>} object, which is essentially a record
2901 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2902 This package object can be inspected using procedures found in the
2903 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2904 returns---surprise!---@code{"hello"}.
2906 With luck, you may be able to import part or all of the definition of
2907 the package you are interested in from another repository, using the
2908 @code{guix import} command (@pxref{Invoking guix import}).
2910 In the example above, @var{hello} is defined in a module of its own,
2911 @code{(gnu packages hello)}. Technically, this is not strictly
2912 necessary, but it is convenient to do so: all the packages defined in
2913 modules under @code{(gnu packages @dots{})} are automatically known to
2914 the command-line tools (@pxref{Package Modules}).
2916 There are a few points worth noting in the above package definition:
2920 The @code{source} field of the package is an @code{<origin>} object
2921 (@pxref{origin Reference}, for the complete reference).
2922 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2923 meaning that the source is a file to be downloaded over FTP or HTTP.
2925 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2926 the GNU mirrors defined in @code{(guix download)}.
2928 The @code{sha256} field specifies the expected SHA256 hash of the file
2929 being downloaded. It is mandatory, and allows Guix to check the
2930 integrity of the file. The @code{(base32 @dots{})} form introduces the
2931 base32 representation of the hash. You can obtain this information with
2932 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2933 hash} (@pxref{Invoking guix hash}).
2936 When needed, the @code{origin} form can also have a @code{patches} field
2937 listing patches to be applied, and a @code{snippet} field giving a
2938 Scheme expression to modify the source code.
2941 @cindex GNU Build System
2942 The @code{build-system} field specifies the procedure to build the
2943 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2944 represents the familiar GNU Build System, where packages may be
2945 configured, built, and installed with the usual @code{./configure &&
2946 make && make check && make install} command sequence.
2949 The @code{arguments} field specifies options for the build system
2950 (@pxref{Build Systems}). Here it is interpreted by
2951 @var{gnu-build-system} as a request run @file{configure} with the
2952 @code{--enable-silent-rules} flag.
2958 What about these quote (@code{'}) characters? They are Scheme syntax to
2959 introduce a literal list; @code{'} is synonymous with @code{quote}.
2960 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2961 for details. Here the value of the @code{arguments} field is a list of
2962 arguments passed to the build system down the road, as with @code{apply}
2963 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2966 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2967 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2968 @code{#:configure-flags} is a keyword used to pass a keyword argument
2969 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2973 The @code{inputs} field specifies inputs to the build process---i.e.,
2974 build-time or run-time dependencies of the package. Here, we define an
2975 input called @code{"gawk"} whose value is that of the @var{gawk}
2976 variable; @var{gawk} is itself bound to a @code{<package>} object.
2978 @cindex backquote (quasiquote)
2981 @cindex comma (unquote)
2985 @findex unquote-splicing
2986 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2987 us to introduce a literal list in the @code{inputs} field, while
2988 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2989 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2992 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2993 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2994 of ensuring that they are present (@pxref{Build Systems}).
2996 However, any other dependencies need to be specified in the
2997 @code{inputs} field. Any dependency not specified here will simply be
2998 unavailable to the build process, possibly leading to a build failure.
3001 @xref{package Reference}, for a full description of possible fields.
3003 Once a package definition is in place, the
3004 package may actually be built using the @code{guix build} command-line
3005 tool (@pxref{Invoking guix build}), troubleshooting any build failures
3006 you encounter (@pxref{Debugging Build Failures}). You can easily jump back to the
3007 package definition using the @command{guix edit} command
3008 (@pxref{Invoking guix edit}).
3009 @xref{Packaging Guidelines}, for
3010 more information on how to test package definitions, and
3011 @ref{Invoking guix lint}, for information on how to check a definition
3012 for style conformance.
3013 @vindex GUIX_PACKAGE_PATH
3014 Lastly, @pxref{Package Modules}, for information
3015 on how to extend the distribution by adding your own package definitions
3016 to @code{GUIX_PACKAGE_PATH}.
3018 Finally, updating the package definition to a new upstream version
3019 can be partly automated by the @command{guix refresh} command
3020 (@pxref{Invoking guix refresh}).
3022 Behind the scenes, a derivation corresponding to the @code{<package>}
3023 object is first computed by the @code{package-derivation} procedure.
3024 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
3025 The build actions it prescribes may then be realized by using the
3026 @code{build-derivations} procedure (@pxref{The Store}).
3028 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
3029 Return the @code{<derivation>} object of @var{package} for @var{system}
3030 (@pxref{Derivations}).
3032 @var{package} must be a valid @code{<package>} object, and @var{system}
3033 must be a string denoting the target system type---e.g.,
3034 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
3035 must be a connection to the daemon, which operates on the store
3036 (@pxref{The Store}).
3040 @cindex cross-compilation
3041 Similarly, it is possible to compute a derivation that cross-builds a
3042 package for some other system:
3044 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
3045 @var{package} @var{target} [@var{system}]
3046 Return the @code{<derivation>} object of @var{package} cross-built from
3047 @var{system} to @var{target}.
3049 @var{target} must be a valid GNU triplet denoting the target hardware
3050 and operating system, such as @code{"mips64el-linux-gnu"}
3051 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
3052 Configure and Build System}).
3055 @cindex package transformations
3056 @cindex input rewriting
3057 @cindex dependency tree rewriting
3058 Packages can be manipulated in arbitrary ways. An example of a useful
3059 transformation is @dfn{input rewriting}, whereby the dependency tree of
3060 a package is rewritten by replacing specific inputs by others:
3062 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
3063 [@var{rewrite-name}]
3064 Return a procedure that, when passed a package, replaces its direct and
3065 indirect dependencies (but not its implicit inputs) according to
3066 @var{replacements}. @var{replacements} is a list of package pairs; the
3067 first element of each pair is the package to replace, and the second one
3070 Optionally, @var{rewrite-name} is a one-argument procedure that takes
3071 the name of a package and returns its new name after rewrite.
3075 Consider this example:
3078 (define libressl-instead-of-openssl
3079 ;; This is a procedure to replace OPENSSL by LIBRESSL,
3081 (package-input-rewriting `((,openssl . ,libressl))))
3083 (define git-with-libressl
3084 (libressl-instead-of-openssl git))
3088 Here we first define a rewriting procedure that replaces @var{openssl}
3089 with @var{libressl}. Then we use it to define a @dfn{variant} of the
3090 @var{git} package that uses @var{libressl} instead of @var{openssl}.
3091 This is exactly what the @option{--with-input} command-line option does
3092 (@pxref{Package Transformation Options, @option{--with-input}}).
3094 A more generic procedure to rewrite a package dependency graph is
3095 @code{package-mapping}: it supports arbitrary changes to nodes in the
3098 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
3099 Return a procedure that, given a package, applies @var{proc} to all the packages
3100 depended on and returns the resulting package. The procedure stops recursion
3101 when @var{cut?} returns true for a given package.
3105 * package Reference :: The package data type.
3106 * origin Reference:: The origin data type.
3110 @node package Reference
3111 @subsection @code{package} Reference
3113 This section summarizes all the options available in @code{package}
3114 declarations (@pxref{Defining Packages}).
3116 @deftp {Data Type} package
3117 This is the data type representing a package recipe.
3121 The name of the package, as a string.
3123 @item @code{version}
3124 The version of the package, as a string.
3127 An object telling how the source code for the package should be
3128 acquired. Most of the time, this is an @code{origin} object, which
3129 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3130 can also be any other ``file-like'' object such as a @code{local-file},
3131 which denotes a file from the local file system (@pxref{G-Expressions,
3132 @code{local-file}}).
3134 @item @code{build-system}
3135 The build system that should be used to build the package (@pxref{Build
3138 @item @code{arguments} (default: @code{'()})
3139 The arguments that should be passed to the build system. This is a
3140 list, typically containing sequential keyword-value pairs.
3142 @item @code{inputs} (default: @code{'()})
3143 @itemx @code{native-inputs} (default: @code{'()})
3144 @itemx @code{propagated-inputs} (default: @code{'()})
3145 @cindex inputs, of packages
3146 These fields list dependencies of the package. Each one is a list of
3147 tuples, where each tuple has a label for the input (a string) as its
3148 first element, a package, origin, or derivation as its second element,
3149 and optionally the name of the output thereof that should be used, which
3150 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3151 more on package outputs). For example, the list below specifies three
3155 `(("libffi" ,libffi)
3156 ("libunistring" ,libunistring)
3157 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3160 @cindex cross compilation, package dependencies
3161 The distinction between @code{native-inputs} and @code{inputs} is
3162 necessary when considering cross-compilation. When cross-compiling,
3163 dependencies listed in @code{inputs} are built for the @emph{target}
3164 architecture; conversely, dependencies listed in @code{native-inputs}
3165 are built for the architecture of the @emph{build} machine.
3167 @code{native-inputs} is typically used to list tools needed at
3168 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3169 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3170 this area (@pxref{Invoking guix lint}).
3172 @anchor{package-propagated-inputs}
3173 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3174 specified packages will be automatically installed alongside the package
3175 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3176 package}}, for information on how @command{guix package} deals with
3179 For example this is necessary when a C/C++ library needs headers of
3180 another library to compile, or when a pkg-config file refers to another
3181 one @i{via} its @code{Requires} field.
3183 Another example where @code{propagated-inputs} is useful is for languages
3184 that lack a facility to record the run-time search path akin to the
3185 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3186 more. To ensure that libraries written in those languages can find
3187 library code they depend on at run time, run-time dependencies must be
3188 listed in @code{propagated-inputs} rather than @code{inputs}.
3190 @item @code{self-native-input?} (default: @code{#f})
3191 This is a Boolean field telling whether the package should use itself as
3192 a native input when cross-compiling.
3194 @item @code{outputs} (default: @code{'("out")})
3195 The list of output names of the package. @xref{Packages with Multiple
3196 Outputs}, for typical uses of additional outputs.
3198 @item @code{native-search-paths} (default: @code{'()})
3199 @itemx @code{search-paths} (default: @code{'()})
3200 A list of @code{search-path-specification} objects describing
3201 search-path environment variables honored by the package.
3203 @item @code{replacement} (default: @code{#f})
3204 This must be either @code{#f} or a package object that will be used as a
3205 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3208 @item @code{synopsis}
3209 A one-line description of the package.
3211 @item @code{description}
3212 A more elaborate description of the package.
3214 @item @code{license}
3215 @cindex license, of packages
3216 The license of the package; a value from @code{(guix licenses)},
3217 or a list of such values.
3219 @item @code{home-page}
3220 The URL to the home-page of the package, as a string.
3222 @item @code{supported-systems} (default: @var{%supported-systems})
3223 The list of systems supported by the package, as strings of the form
3224 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3226 @item @code{maintainers} (default: @code{'()})
3227 The list of maintainers of the package, as @code{maintainer} objects.
3229 @item @code{location} (default: source location of the @code{package} form)
3230 The source location of the package. It is useful to override this when
3231 inheriting from another package, in which case this field is not
3232 automatically corrected.
3237 @node origin Reference
3238 @subsection @code{origin} Reference
3240 This section summarizes all the options available in @code{origin}
3241 declarations (@pxref{Defining Packages}).
3243 @deftp {Data Type} origin
3244 This is the data type representing a source code origin.
3248 An object containing the URI of the source. The object type depends on
3249 the @code{method} (see below). For example, when using the
3250 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3251 values are: a URL represented as a string, or a list thereof.
3254 A procedure that handles the URI.
3259 @item @var{url-fetch} from @code{(guix download)}
3260 download a file from the HTTP, HTTPS, or FTP URL specified in the
3264 @item @var{git-fetch} from @code{(guix git-download)}
3265 clone the Git version control repository, and check out the revision
3266 specified in the @code{uri} field as a @code{git-reference} object; a
3267 @code{git-reference} looks like this:
3271 (url "git://git.debian.org/git/pkg-shadow/shadow")
3272 (commit "v4.1.5.1"))
3277 A bytevector containing the SHA-256 hash of the source. Typically the
3278 @code{base32} form is used here to generate the bytevector from a
3281 You can obtain this information using @code{guix download}
3282 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3285 @item @code{file-name} (default: @code{#f})
3286 The file name under which the source code should be saved. When this is
3287 @code{#f}, a sensible default value will be used in most cases. In case
3288 the source is fetched from a URL, the file name from the URL will be
3289 used. For version control checkouts, it is recommended to provide the
3290 file name explicitly because the default is not very descriptive.
3292 @item @code{patches} (default: @code{'()})
3293 A list of file names, origins, or file-like objects (@pxref{G-Expressions,
3294 file-like objects}) pointing to patches to be applied to the source.
3296 This list of patches must be unconditional. In particular, it cannot
3297 depend on the value of @code{%current-system} or
3298 @code{%current-target-system}.
3300 @item @code{snippet} (default: @code{#f})
3301 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3302 in the source directory. This is a convenient way to modify the source,
3303 sometimes more convenient than a patch.
3305 @item @code{patch-flags} (default: @code{'("-p1")})
3306 A list of command-line flags that should be passed to the @code{patch}
3309 @item @code{patch-inputs} (default: @code{#f})
3310 Input packages or derivations to the patching process. When this is
3311 @code{#f}, the usual set of inputs necessary for patching are provided,
3312 such as GNU@tie{}Patch.
3314 @item @code{modules} (default: @code{'()})
3315 A list of Guile modules that should be loaded during the patching
3316 process and while running the code in the @code{snippet} field.
3318 @item @code{patch-guile} (default: @code{#f})
3319 The Guile package that should be used in the patching process. When
3320 this is @code{#f}, a sensible default is used.
3326 @section Build Systems
3328 @cindex build system
3329 Each package definition specifies a @dfn{build system} and arguments for
3330 that build system (@pxref{Defining Packages}). This @code{build-system}
3331 field represents the build procedure of the package, as well as implicit
3332 dependencies of that build procedure.
3334 Build systems are @code{<build-system>} objects. The interface to
3335 create and manipulate them is provided by the @code{(guix build-system)}
3336 module, and actual build systems are exported by specific modules.
3338 @cindex bag (low-level package representation)
3339 Under the hood, build systems first compile package objects to
3340 @dfn{bags}. A @dfn{bag} is like a package, but with less
3341 ornamentation---in other words, a bag is a lower-level representation of
3342 a package, which includes all the inputs of that package, including some
3343 that were implicitly added by the build system. This intermediate
3344 representation is then compiled to a derivation (@pxref{Derivations}).
3346 Build systems accept an optional list of @dfn{arguments}. In package
3347 definitions, these are passed @i{via} the @code{arguments} field
3348 (@pxref{Defining Packages}). They are typically keyword arguments
3349 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3350 Guile Reference Manual}). The value of these arguments is usually
3351 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3352 by the daemon (@pxref{Derivations}).
3354 The main build system is @var{gnu-build-system}, which implements the
3355 standard build procedure for GNU and many other packages. It
3356 is provided by the @code{(guix build-system gnu)} module.
3358 @defvr {Scheme Variable} gnu-build-system
3359 @var{gnu-build-system} represents the GNU Build System, and variants
3360 thereof (@pxref{Configuration, configuration and makefile conventions,,
3361 standards, GNU Coding Standards}).
3363 @cindex build phases
3364 In a nutshell, packages using it are configured, built, and installed with
3365 the usual @code{./configure && make && make check && make install}
3366 command sequence. In practice, a few additional steps are often needed.
3367 All these steps are split up in separate @dfn{phases},
3368 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3369 modules for more details about the build phases.}:
3373 Unpack the source tarball, and change the current directory to the
3374 extracted source tree. If the source is actually a directory, copy it
3375 to the build tree, and enter that directory.
3377 @item patch-source-shebangs
3378 Patch shebangs encountered in source files so they refer to the right
3379 store file names. For instance, this changes @code{#!/bin/sh} to
3380 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3383 Run the @file{configure} script with a number of default options, such
3384 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3385 by the @code{#:configure-flags} argument.
3388 Run @code{make} with the list of flags specified with
3389 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3390 (the default), build with @code{make -j}.
3393 Run @code{make check}, or some other target specified with
3394 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3395 @code{#:parallel-tests?} argument is true (the default), run @code{make
3399 Run @code{make install} with the flags listed in @code{#:make-flags}.
3401 @item patch-shebangs
3402 Patch shebangs on the installed executable files.
3405 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3406 is false), copying them to the @code{debug} output when available
3407 (@pxref{Installing Debugging Files}).
3410 @vindex %standard-phases
3411 The build-side module @code{(guix build gnu-build-system)} defines
3412 @var{%standard-phases} as the default list of build phases.
3413 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3414 procedure implements the actual phase.
3416 The list of phases used for a particular package can be changed with the
3417 @code{#:phases} parameter. For instance, passing:
3420 #:phases (modify-phases %standard-phases (delete 'configure))
3423 means that all the phases described above will be used, except the
3424 @code{configure} phase.
3426 In addition, this build system ensures that the ``standard'' environment
3427 for GNU packages is available. This includes tools such as GCC, libc,
3428 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3429 build-system gnu)} module for a complete list). We call these the
3430 @dfn{implicit inputs} of a package, because package definitions do not
3431 have to mention them.
3434 Other @code{<build-system>} objects are defined to support other
3435 conventions and tools used by free software packages. They inherit most
3436 of @var{gnu-build-system}, and differ mainly in the set of inputs
3437 implicitly added to the build process, and in the list of phases
3438 executed. Some of these build systems are listed below.
3440 @defvr {Scheme Variable} ant-build-system
3441 This variable is exported by @code{(guix build-system ant)}. It
3442 implements the build procedure for Java packages that can be built with
3443 @url{http://ant.apache.org/, Ant build tool}.
3445 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3446 provided by the @code{icedtea} package to the set of inputs. Different
3447 packages can be specified with the @code{#:ant} and @code{#:jdk}
3448 parameters, respectively.
3450 When the original package does not provide a suitable Ant build file,
3451 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3452 build file @file{build.xml} with tasks to build the specified jar
3453 archive. In this case the parameter @code{#:source-dir} can be used to
3454 specify the source sub-directory, defaulting to ``src''.
3456 The parameter @code{#:build-target} can be used to specify the Ant task
3457 that should be run during the @code{build} phase. By default the
3458 ``jar'' task will be run.
3462 @defvr {Scheme Variable} asdf-build-system/source
3463 @defvrx {Scheme Variable} asdf-build-system/sbcl
3464 @defvrx {Scheme Variable} asdf-build-system/ecl
3466 These variables, exported by @code{(guix build-system asdf)}, implement
3467 build procedures for Common Lisp packages using
3468 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3469 definition facility for Common Lisp programs and libraries.
3471 The @code{asdf-build-system/source} system installs the packages in
3472 source form, and can be loaded using any common lisp implementation, via
3473 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3474 systems in the format which a particular implementation understands.
3475 These build systems can also be used to produce executable programs, or
3476 lisp images which contain a set of packages pre-loaded.
3478 The build system uses naming conventions. For binary packages, the
3479 package name should be prefixed with the lisp implementation, such as
3480 @code{sbcl-} for @code{asdf-build-system/sbcl}.
3482 Additionally, the corresponding source package should be labeled using
3483 the same convention as python packages (see @ref{Python Modules}), using
3484 the @code{cl-} prefix.
3486 For binary packages, each system should be defined as a Guix package.
3487 If one package @code{origin} contains several systems, package variants
3488 can be created in order to build all the systems. Source packages,
3489 which use @code{asdf-build-system/source}, may contain several systems.
3491 In order to create executable programs and images, the build-side
3492 procedures @code{build-program} and @code{build-image} can be used.
3493 They should be called in a build phase after the @code{create-symlinks}
3494 phase, so that the system which was just built can be used within the
3495 resulting image. @code{build-program} requires a list of Common Lisp
3496 expressions to be passed as the @code{#:entry-program} argument.
3498 If the system is not defined within its own @code{.asd} file of the same
3499 name, then the @code{#:asd-file} parameter should be used to specify
3500 which file the system is defined in. Furthermore, if the package
3501 defines a system for its tests in a separate file, it will be loaded
3502 before the tests are run if it is specified by the
3503 @code{#:test-asd-file} parameter. If it is not set, the files
3504 @code{<system>-tests.asd}, @code{<system>-test.asd}, @code{tests.asd},
3505 and @code{test.asd} will be tried if they exist.
3507 If for some reason the package must be named in a different way than the
3508 naming conventions suggest, the @code{#:asd-system-name} parameter can
3509 be used to specify the name of the system.
3513 @defvr {Scheme Variable} cargo-build-system
3514 @cindex Rust programming language
3515 @cindex Cargo (Rust build system)
3516 This variable is exported by @code{(guix build-system cargo)}. It
3517 supports builds of packages using Cargo, the build tool of the
3518 @uref{https://www.rust-lang.org, Rust programming language}.
3520 In its @code{configure} phase, this build system replaces dependencies
3521 specified in the @file{Carto.toml} file with inputs to the Guix package.
3522 The @code{install} phase installs the binaries, and it also installs the
3523 source code and @file{Cargo.toml} file.
3526 @defvr {Scheme Variable} cmake-build-system
3527 This variable is exported by @code{(guix build-system cmake)}. It
3528 implements the build procedure for packages using the
3529 @url{http://www.cmake.org, CMake build tool}.
3531 It automatically adds the @code{cmake} package to the set of inputs.
3532 Which package is used can be specified with the @code{#:cmake}
3535 The @code{#:configure-flags} parameter is taken as a list of flags
3536 passed to the @command{cmake} command. The @code{#:build-type}
3537 parameter specifies in abstract terms the flags passed to the compiler;
3538 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3539 debugging information''), which roughly means that code is compiled with
3540 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3543 @defvr {Scheme Variable} glib-or-gtk-build-system
3544 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3545 is intended for use with packages making use of GLib or GTK+.
3547 This build system adds the following two phases to the ones defined by
3548 @var{gnu-build-system}:
3551 @item glib-or-gtk-wrap
3552 The phase @code{glib-or-gtk-wrap} ensures that programs in
3553 @file{bin/} are able to find GLib ``schemas'' and
3554 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3555 modules}. This is achieved by wrapping the programs in launch scripts
3556 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3557 environment variables.
3559 It is possible to exclude specific package outputs from that wrapping
3560 process by listing their names in the
3561 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3562 when an output is known not to contain any GLib or GTK+ binaries, and
3563 where wrapping would gratuitously add a dependency of that output on
3566 @item glib-or-gtk-compile-schemas
3567 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3568 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3569 GSettings schemas} of GLib are compiled. Compilation is performed by the
3570 @command{glib-compile-schemas} program. It is provided by the package
3571 @code{glib:bin} which is automatically imported by the build system.
3572 The @code{glib} package providing @command{glib-compile-schemas} can be
3573 specified with the @code{#:glib} parameter.
3576 Both phases are executed after the @code{install} phase.
3579 @defvr {Scheme Variable} minify-build-system
3580 This variable is exported by @code{(guix build-system minify)}. It
3581 implements a minification procedure for simple JavaScript packages.
3583 It adds @code{uglify-js} to the set of inputs and uses it to compress
3584 all JavaScript files in the @file{src} directory. A different minifier
3585 package can be specified with the @code{#:uglify-js} parameter, but it
3586 is expected that the package writes the minified code to the standard
3589 When the input JavaScript files are not all located in the @file{src}
3590 directory, the parameter @code{#:javascript-files} can be used to
3591 specify a list of file names to feed to the minifier.
3594 @defvr {Scheme Variable} ocaml-build-system
3595 This variable is exported by @code{(guix build-system ocaml)}. It implements
3596 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3597 of choosing the correct set of commands to run for each package. OCaml
3598 packages can expect many different commands to be run. This build system will
3601 When the package has a @file{setup.ml} file present at the top-level, it will
3602 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3603 @code{ocaml setup.ml -install}. The build system will assume that this file
3604 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3605 care of setting the prefix and enabling tests if they are not disabled. You
3606 can pass configure and build flags with the @code{#:configure-flags} and
3607 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3608 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3609 bypass this system in the build and install phases.
3611 When the package has a @file{configure} file, it is assumed that it is a
3612 hand-made configure script that requires a different argument format than
3613 in the @code{gnu-build-system}. You can add more flags with the
3614 @code{#:configure-flags} key.
3616 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3617 @code{#t}), it will be used and more flags can be passed to the build and
3618 install phases with the @code{#:make-flags} key.
3620 Finally, some packages do not have these files and use a somewhat standard
3621 location for its build system. In that case, the build system will run
3622 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3623 providing the path to the required findlib module. Additional flags can
3624 be passed via the @code{#:build-flags} key. Install is taken care of by
3625 @command{opam-installer}. In this case, the @code{opam} package must
3626 be added to the @code{native-inputs} field of the package definition.
3628 Note that most OCaml packages assume they will be installed in the same
3629 directory as OCaml, which is not what we want in guix. In particular, they
3630 will install @file{.so} files in their module's directory, which is usually
3631 fine because it is in the OCaml compiler directory. In guix though, these
3632 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3633 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3634 @file{.so} libraries should be installed.
3637 @defvr {Scheme Variable} python-build-system
3638 This variable is exported by @code{(guix build-system python)}. It
3639 implements the more or less standard build procedure used by Python
3640 packages, which consists in running @code{python setup.py build} and
3641 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3643 For packages that install stand-alone Python programs under @code{bin/},
3644 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3645 environment variable points to all the Python libraries they depend on.
3647 Which Python package is used to perform the build can be specified with
3648 the @code{#:python} parameter. This is a useful way to force a package
3649 to be built for a specific version of the Python interpreter, which
3650 might be necessary if the package is only compatible with a single
3651 interpreter version.
3653 By default guix calls @code{setup.py} under control of
3654 @code{setuptools}, much like @command{pip} does. Some packages are not
3655 compatible with setuptools (and pip), thus you can disable this by
3656 setting the @code{#:use-setuptools} parameter to @code{#f}.
3659 @defvr {Scheme Variable} perl-build-system
3660 This variable is exported by @code{(guix build-system perl)}. It
3661 implements the standard build procedure for Perl packages, which either
3662 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3663 followed by @code{Build} and @code{Build install}; or in running
3664 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3665 @code{make} and @code{make install}, depending on which of
3666 @code{Build.PL} or @code{Makefile.PL} is present in the package
3667 distribution. Preference is given to the former if both @code{Build.PL}
3668 and @code{Makefile.PL} exist in the package distribution. This
3669 preference can be reversed by specifying @code{#t} for the
3670 @code{#:make-maker?} parameter.
3672 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3673 passes flags specified by the @code{#:make-maker-flags} or
3674 @code{#:module-build-flags} parameter, respectively.
3676 Which Perl package is used can be specified with @code{#:perl}.
3679 @defvr {Scheme Variable} r-build-system
3680 This variable is exported by @code{(guix build-system r)}. It
3681 implements the build procedure used by @uref{http://r-project.org, R}
3682 packages, which essentially is little more than running @code{R CMD
3683 INSTALL --library=/gnu/store/@dots{}} in an environment where
3684 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3685 are run after installation using the R function
3686 @code{tools::testInstalledPackage}.
3689 @defvr {Scheme Variable} texlive-build-system
3690 This variable is exported by @code{(guix build-system texlive)}. It is
3691 used to build TeX packages in batch mode with a specified engine. The
3692 build system sets the @code{TEXINPUTS} variable to find all TeX source
3693 files in the inputs.
3695 By default it runs @code{luatex} on all files ending on @code{ins}. A
3696 different engine and format can be specified with the
3697 @code{#:tex-format} argument. Different build targets can be specified
3698 with the @code{#:build-targets} argument, which expects a list of file
3699 names. The build system adds only @code{texlive-bin} and
3700 @code{texlive-latex-base} (both from @code{(gnu packages tex}) to the
3701 inputs. Both can be overridden with the arguments @code{#:texlive-bin}
3702 and @code{#:texlive-latex-base}, respectively.
3704 The @code{#:tex-directory} parameter tells the build system where to
3705 install the built files under the texmf tree.
3708 @defvr {Scheme Variable} ruby-build-system
3709 This variable is exported by @code{(guix build-system ruby)}. It
3710 implements the RubyGems build procedure used by Ruby packages, which
3711 involves running @code{gem build} followed by @code{gem install}.
3713 The @code{source} field of a package that uses this build system
3714 typically references a gem archive, since this is the format that Ruby
3715 developers use when releasing their software. The build system unpacks
3716 the gem archive, potentially patches the source, runs the test suite,
3717 repackages the gem, and installs it. Additionally, directories and
3718 tarballs may be referenced to allow building unreleased gems from Git or
3719 a traditional source release tarball.
3721 Which Ruby package is used can be specified with the @code{#:ruby}
3722 parameter. A list of additional flags to be passed to the @command{gem}
3723 command can be specified with the @code{#:gem-flags} parameter.
3726 @defvr {Scheme Variable} waf-build-system
3727 This variable is exported by @code{(guix build-system waf)}. It
3728 implements a build procedure around the @code{waf} script. The common
3729 phases---@code{configure}, @code{build}, and @code{install}---are
3730 implemented by passing their names as arguments to the @code{waf}
3733 The @code{waf} script is executed by the Python interpreter. Which
3734 Python package is used to run the script can be specified with the
3735 @code{#:python} parameter.
3738 @defvr {Scheme Variable} haskell-build-system
3739 This variable is exported by @code{(guix build-system haskell)}. It
3740 implements the Cabal build procedure used by Haskell packages, which
3741 involves running @code{runhaskell Setup.hs configure
3742 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3743 Instead of installing the package by running @code{runhaskell Setup.hs
3744 install}, to avoid trying to register libraries in the read-only
3745 compiler store directory, the build system uses @code{runhaskell
3746 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3747 addition, the build system generates the package documentation by
3748 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3749 is passed. Optional Haddock parameters can be passed with the help of
3750 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3751 not found, the build system looks for @code{Setup.lhs} instead.
3753 Which Haskell compiler is used can be specified with the @code{#:haskell}
3754 parameter which defaults to @code{ghc}.
3757 @defvr {Scheme Variable} dub-build-system
3758 This variable is exported by @code{(guix build-system dub)}. It
3759 implements the Dub build procedure used by D packages, which
3760 involves running @code{dub build} and @code{dub run}.
3761 Installation is done by copying the files manually.
3763 Which D compiler is used can be specified with the @code{#:ldc}
3764 parameter which defaults to @code{ldc}.
3767 @defvr {Scheme Variable} emacs-build-system
3768 This variable is exported by @code{(guix build-system emacs)}. It
3769 implements an installation procedure similar to the packaging system
3770 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3772 It first creates the @code{@var{package}-autoloads.el} file, then it
3773 byte compiles all Emacs Lisp files. Differently from the Emacs
3774 packaging system, the Info documentation files are moved to the standard
3775 documentation directory and the @file{dir} file is deleted. Each
3776 package is installed in its own directory under
3777 @file{share/emacs/site-lisp/guix.d}.
3780 @defvr {Scheme Variable} font-build-system
3781 This variable is exported by @code{(guix build-system font)}. It
3782 implements an installation procedure for font packages where upstream
3783 provides pre-compiled TrueType, OpenType, etc. font files that merely
3784 need to be copied into place. It copies font files to standard
3785 locations in the output directory.
3788 Lastly, for packages that do not need anything as sophisticated, a
3789 ``trivial'' build system is provided. It is trivial in the sense that
3790 it provides basically no support: it does not pull any implicit inputs,
3791 and does not have a notion of build phases.
3793 @defvr {Scheme Variable} trivial-build-system
3794 This variable is exported by @code{(guix build-system trivial)}.
3796 This build system requires a @code{#:builder} argument. This argument
3797 must be a Scheme expression that builds the package output(s)---as
3798 with @code{build-expression->derivation} (@pxref{Derivations,
3799 @code{build-expression->derivation}}).
3809 Conceptually, the @dfn{store} is the place where derivations that have
3810 been built successfully are stored---by default, @file{/gnu/store}.
3811 Sub-directories in the store are referred to as @dfn{store items} or
3812 sometimes @dfn{store paths}. The store has an associated database that
3813 contains information such as the store paths referred to by each store
3814 path, and the list of @emph{valid} store items---results of successful
3815 builds. This database resides in @file{@var{localstatedir}/guix/db},
3816 where @var{localstatedir} is the state directory specified @i{via}
3817 @option{--localstatedir} at configure time, usually @file{/var}.
3819 The store is @emph{always} accessed by the daemon on behalf of its clients
3820 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3821 connect to the daemon over a Unix-domain socket, send requests to it,
3822 and read the result---these are remote procedure calls, or RPCs.
3825 Users must @emph{never} modify files under @file{/gnu/store} directly.
3826 This would lead to inconsistencies and break the immutability
3827 assumptions of Guix's functional model (@pxref{Introduction}).
3829 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3830 how to check the integrity of the store and attempt recovery from
3831 accidental modifications.
3834 The @code{(guix store)} module provides procedures to connect to the
3835 daemon, and to perform RPCs. These are described below. By default,
3836 @code{open-connection}, and thus all the @command{guix} commands,
3837 connect to the local daemon or to the URI specified by the
3838 @code{GUIX_DAEMON_SOCKET} environment variable.
3840 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3841 When set, the value of this variable should be a file name or a URI
3842 designating the daemon endpoint. When it is a file name, it denotes a
3843 Unix-domain socket to connect to. In addition to file names, the
3844 supported URI schemes are:
3849 These are for Unix-domain sockets.
3850 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3851 @file{/var/guix/daemon-socket/socket}.
3854 @cindex daemon, remote access
3855 @cindex remote access to the daemon
3856 @cindex daemon, cluster setup
3857 @cindex clusters, daemon setup
3858 These URIs denote connections over TCP/IP, without encryption nor
3859 authentication of the remote host. The URI must specify the host name
3860 and optionally a port number (by default port 44146 is used):
3863 guix://master.guix.example.org:1234
3866 This setup is suitable on local networks, such as clusters, where only
3867 trusted nodes may connect to the build daemon at
3868 @code{master.guix.example.org}.
3870 The @code{--listen} option of @command{guix-daemon} can be used to
3871 instruct it to listen for TCP connections (@pxref{Invoking guix-daemon,
3875 @cindex SSH access to build daemons
3876 These URIs allow you to connect to a remote daemon over
3877 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
3878 A typical URL might look like this:
3881 ssh://charlie@@guix.example.org:22
3884 As for @command{guix copy}, the usual OpenSSH client configuration files
3885 are honored (@pxref{Invoking guix copy}).
3888 Additional URI schemes may be supported in the future.
3890 @c XXX: Remove this note when the protocol incurs fewer round trips
3891 @c and when (guix derivations) no longer relies on file system access.
3893 The ability to connect to remote build daemons is considered
3894 experimental as of @value{VERSION}. Please get in touch with us to
3895 share any problems or suggestions you may have (@pxref{Contributing}).
3899 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
3900 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
3901 @var{reserve-space?} is true, instruct it to reserve a little bit of
3902 extra space on the file system so that the garbage collector can still
3903 operate should the disk become full. Return a server object.
3905 @var{file} defaults to @var{%default-socket-path}, which is the normal
3906 location given the options that were passed to @command{configure}.
3909 @deffn {Scheme Procedure} close-connection @var{server}
3910 Close the connection to @var{server}.
3913 @defvr {Scheme Variable} current-build-output-port
3914 This variable is bound to a SRFI-39 parameter, which refers to the port
3915 where build and error logs sent by the daemon should be written.
3918 Procedures that make RPCs all take a server object as their first
3921 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3922 @cindex invalid store items
3923 Return @code{#t} when @var{path} designates a valid store item and
3924 @code{#f} otherwise (an invalid item may exist on disk but still be
3925 invalid, for instance because it is the result of an aborted or failed
3928 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3929 prefixed by the store directory (@file{/gnu/store}).
3932 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3933 Add @var{text} under file @var{name} in the store, and return its store
3934 path. @var{references} is the list of store paths referred to by the
3935 resulting store path.
3938 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3939 Build @var{derivations} (a list of @code{<derivation>} objects or
3940 derivation paths), and return when the worker is done building them.
3941 Return @code{#t} on success.
3944 Note that the @code{(guix monads)} module provides a monad as well as
3945 monadic versions of the above procedures, with the goal of making it
3946 more convenient to work with code that accesses the store (@pxref{The
3950 @i{This section is currently incomplete.}
3953 @section Derivations
3956 Low-level build actions and the environment in which they are performed
3957 are represented by @dfn{derivations}. A derivation contains the
3958 following pieces of information:
3962 The outputs of the derivation---derivations produce at least one file or
3963 directory in the store, but may produce more.
3966 The inputs of the derivations, which may be other derivations or plain
3967 files in the store (patches, build scripts, etc.)
3970 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3973 The file name of a build script in the store, along with the arguments
3977 A list of environment variables to be defined.
3981 @cindex derivation path
3982 Derivations allow clients of the daemon to communicate build actions to
3983 the store. They exist in two forms: as an in-memory representation,
3984 both on the client- and daemon-side, and as files in the store whose
3985 name end in @code{.drv}---these files are referred to as @dfn{derivation
3986 paths}. Derivations paths can be passed to the @code{build-derivations}
3987 procedure to perform the build actions they prescribe (@pxref{The
3990 The @code{(guix derivations)} module provides a representation of
3991 derivations as Scheme objects, along with procedures to create and
3992 otherwise manipulate derivations. The lowest-level primitive to create
3993 a derivation is the @code{derivation} procedure:
3995 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3996 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3997 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3998 [#:system (%current-system)] [#:references-graphs #f] @
3999 [#:allowed-references #f] [#:disallowed-references #f] @
4000 [#:leaked-env-vars #f] [#:local-build? #f] @
4001 [#:substitutable? #t]
4002 Build a derivation with the given arguments, and return the resulting
4003 @code{<derivation>} object.
4005 When @var{hash} and @var{hash-algo} are given, a
4006 @dfn{fixed-output derivation} is created---i.e., one whose result is
4007 known in advance, such as a file download. If, in addition,
4008 @var{recursive?} is true, then that fixed output may be an executable
4009 file or a directory and @var{hash} must be the hash of an archive
4010 containing this output.
4012 When @var{references-graphs} is true, it must be a list of file
4013 name/store path pairs. In that case, the reference graph of each store
4014 path is exported in the build environment in the corresponding file, in
4015 a simple text format.
4017 When @var{allowed-references} is true, it must be a list of store items
4018 or outputs that the derivation's output may refer to. Likewise,
4019 @var{disallowed-references}, if true, must be a list of things the
4020 outputs may @emph{not} refer to.
4022 When @var{leaked-env-vars} is true, it must be a list of strings
4023 denoting environment variables that are allowed to ``leak'' from the
4024 daemon's environment to the build environment. This is only applicable
4025 to fixed-output derivations---i.e., when @var{hash} is true. The main
4026 use is to allow variables such as @code{http_proxy} to be passed to
4027 derivations that download files.
4029 When @var{local-build?} is true, declare that the derivation is not a
4030 good candidate for offloading and should rather be built locally
4031 (@pxref{Daemon Offload Setup}). This is the case for small derivations
4032 where the costs of data transfers would outweigh the benefits.
4034 When @var{substitutable?} is false, declare that substitutes of the
4035 derivation's output should not be used (@pxref{Substitutes}). This is
4036 useful, for instance, when building packages that capture details of the
4037 host CPU instruction set.
4041 Here's an example with a shell script as its builder, assuming
4042 @var{store} is an open connection to the daemon, and @var{bash} points
4043 to a Bash executable in the store:
4046 (use-modules (guix utils)
4050 (let ((builder ; add the Bash script to the store
4051 (add-text-to-store store "my-builder.sh"
4052 "echo hello world > $out\n" '())))
4053 (derivation store "foo"
4054 bash `("-e" ,builder)
4055 #:inputs `((,bash) (,builder))
4056 #:env-vars '(("HOME" . "/homeless"))))
4057 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
4060 As can be guessed, this primitive is cumbersome to use directly. A
4061 better approach is to write build scripts in Scheme, of course! The
4062 best course of action for that is to write the build code as a
4063 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
4064 information, @pxref{G-Expressions}.
4066 Once upon a time, @code{gexp->derivation} did not exist and constructing
4067 derivations with build code written in Scheme was achieved with
4068 @code{build-expression->derivation}, documented below. This procedure
4069 is now deprecated in favor of the much nicer @code{gexp->derivation}.
4071 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
4072 @var{name} @var{exp} @
4073 [#:system (%current-system)] [#:inputs '()] @
4074 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
4075 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4076 [#:references-graphs #f] [#:allowed-references #f] @
4077 [#:disallowed-references #f] @
4078 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4079 Return a derivation that executes Scheme expression @var{exp} as a
4080 builder for derivation @var{name}. @var{inputs} must be a list of
4081 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
4082 @code{"out"} is assumed. @var{modules} is a list of names of Guile
4083 modules from the current search path to be copied in the store,
4084 compiled, and made available in the load path during the execution of
4085 @var{exp}---e.g., @code{((guix build utils) (guix build
4086 gnu-build-system))}.
4088 @var{exp} is evaluated in an environment where @code{%outputs} is bound
4089 to a list of output/path pairs, and where @code{%build-inputs} is bound
4090 to a list of string/output-path pairs made from @var{inputs}.
4091 Optionally, @var{env-vars} is a list of string pairs specifying the name
4092 and value of environment variables visible to the builder. The builder
4093 terminates by passing the result of @var{exp} to @code{exit}; thus, when
4094 @var{exp} returns @code{#f}, the build is considered to have failed.
4096 @var{exp} is built using @var{guile-for-build} (a derivation). When
4097 @var{guile-for-build} is omitted or is @code{#f}, the value of the
4098 @code{%guile-for-build} fluid is used instead.
4100 See the @code{derivation} procedure for the meaning of
4101 @var{references-graphs}, @var{allowed-references},
4102 @var{disallowed-references}, @var{local-build?}, and
4103 @var{substitutable?}.
4107 Here's an example of a single-output derivation that creates a directory
4108 containing one file:
4111 (let ((builder '(let ((out (assoc-ref %outputs "out")))
4112 (mkdir out) ; create /gnu/store/@dots{}-goo
4113 (call-with-output-file (string-append out "/test")
4115 (display '(hello guix) p))))))
4116 (build-expression->derivation store "goo" builder))
4118 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
4122 @node The Store Monad
4123 @section The Store Monad
4127 The procedures that operate on the store described in the previous
4128 sections all take an open connection to the build daemon as their first
4129 argument. Although the underlying model is functional, they either have
4130 side effects or depend on the current state of the store.
4132 The former is inconvenient: the connection to the build daemon has to be
4133 carried around in all those functions, making it impossible to compose
4134 functions that do not take that parameter with functions that do. The
4135 latter can be problematic: since store operations have side effects
4136 and/or depend on external state, they have to be properly sequenced.
4138 @cindex monadic values
4139 @cindex monadic functions
4140 This is where the @code{(guix monads)} module comes in. This module
4141 provides a framework for working with @dfn{monads}, and a particularly
4142 useful monad for our uses, the @dfn{store monad}. Monads are a
4143 construct that allows two things: associating ``context'' with values
4144 (in our case, the context is the store), and building sequences of
4145 computations (here computations include accesses to the store). Values
4146 in a monad---values that carry this additional context---are called
4147 @dfn{monadic values}; procedures that return such values are called
4148 @dfn{monadic procedures}.
4150 Consider this ``normal'' procedure:
4153 (define (sh-symlink store)
4154 ;; Return a derivation that symlinks the 'bash' executable.
4155 (let* ((drv (package-derivation store bash))
4156 (out (derivation->output-path drv))
4157 (sh (string-append out "/bin/bash")))
4158 (build-expression->derivation store "sh"
4159 `(symlink ,sh %output))))
4162 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
4163 as a monadic function:
4166 (define (sh-symlink)
4167 ;; Same, but return a monadic value.
4168 (mlet %store-monad ((drv (package->derivation bash)))
4169 (gexp->derivation "sh"
4170 #~(symlink (string-append #$drv "/bin/bash")
4174 There are several things to note in the second version: the @code{store}
4175 parameter is now implicit and is ``threaded'' in the calls to the
4176 @code{package->derivation} and @code{gexp->derivation} monadic
4177 procedures, and the monadic value returned by @code{package->derivation}
4178 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4180 As it turns out, the call to @code{package->derivation} can even be
4181 omitted since it will take place implicitly, as we will see later
4182 (@pxref{G-Expressions}):
4185 (define (sh-symlink)
4186 (gexp->derivation "sh"
4187 #~(symlink (string-append #$bash "/bin/bash")
4192 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4193 @c for the funny quote.
4194 Calling the monadic @code{sh-symlink} has no effect. As someone once
4195 said, ``you exit a monad like you exit a building on fire: by running''.
4196 So, to exit the monad and get the desired effect, one must use
4197 @code{run-with-store}:
4200 (run-with-store (open-connection) (sh-symlink))
4201 @result{} /gnu/store/...-sh-symlink
4204 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4205 new ``meta-commands'' to make it easier to deal with monadic procedures:
4206 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4207 to ``run'' a single monadic value through the store:
4210 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4211 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4214 The latter enters a recursive REPL, where all the return values are
4215 automatically run through the store:
4218 scheme@@(guile-user)> ,enter-store-monad
4219 store-monad@@(guile-user) [1]> (package->derivation hello)
4220 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4221 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4222 $3 = "/gnu/store/@dots{}-foo"
4223 store-monad@@(guile-user) [1]> ,q
4224 scheme@@(guile-user)>
4228 Note that non-monadic values cannot be returned in the
4229 @code{store-monad} REPL.
4231 The main syntactic forms to deal with monads in general are provided by
4232 the @code{(guix monads)} module and are described below.
4234 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4235 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4239 @deffn {Scheme Syntax} return @var{val}
4240 Return a monadic value that encapsulates @var{val}.
4243 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4244 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4245 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4246 referred to as ``bind'', but that name denotes an unrelated procedure in
4247 Guile. Thus we use this somewhat cryptic symbol inherited from the
4248 Haskell language.}. There can be one @var{mproc} or several of them, as
4253 (with-monad %state-monad
4255 (lambda (x) (return (+ 1 x)))
4256 (lambda (x) (return (* 2 x)))))
4260 @result{} some-state
4264 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4266 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4268 Bind the variables @var{var} to the monadic values @var{mval} in
4269 @var{body}, which is a sequence of expressions. As with the bind
4270 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4271 value ``contained'' in @var{mval} and making @var{var} refer to that
4272 raw, non-monadic value within the scope of the @var{body}. The form
4273 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4274 @var{val}, as per @code{let}. The binding operations occur in sequence
4275 from left to right. The last expression of @var{body} must be a monadic
4276 expression, and its result will become the result of the @code{mlet} or
4277 @code{mlet*} when run in the @var{monad}.
4279 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4280 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4283 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4284 Bind @var{mexp} and the following monadic expressions in sequence,
4285 returning the result of the last expression. Every expression in the
4286 sequence must be a monadic expression.
4288 This is akin to @code{mlet}, except that the return values of the
4289 monadic expressions are ignored. In that sense, it is analogous to
4290 @code{begin}, but applied to monadic expressions.
4293 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4294 When @var{condition} is true, evaluate the sequence of monadic
4295 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4296 @var{condition} is false, return @code{*unspecified*} in the current
4297 monad. Every expression in the sequence must be a monadic expression.
4300 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4301 When @var{condition} is false, evaluate the sequence of monadic
4302 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4303 @var{condition} is true, return @code{*unspecified*} in the current
4304 monad. Every expression in the sequence must be a monadic expression.
4308 The @code{(guix monads)} module provides the @dfn{state monad}, which
4309 allows an additional value---the state---to be @emph{threaded} through
4310 monadic procedure calls.
4312 @defvr {Scheme Variable} %state-monad
4313 The state monad. Procedures in the state monad can access and change
4314 the state that is threaded.
4316 Consider the example below. The @code{square} procedure returns a value
4317 in the state monad. It returns the square of its argument, but also
4318 increments the current state value:
4322 (mlet %state-monad ((count (current-state)))
4323 (mbegin %state-monad
4324 (set-current-state (+ 1 count))
4327 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4332 When ``run'' through @var{%state-monad}, we obtain that additional state
4333 value, which is the number of @code{square} calls.
4336 @deffn {Monadic Procedure} current-state
4337 Return the current state as a monadic value.
4340 @deffn {Monadic Procedure} set-current-state @var{value}
4341 Set the current state to @var{value} and return the previous state as a
4345 @deffn {Monadic Procedure} state-push @var{value}
4346 Push @var{value} to the current state, which is assumed to be a list,
4347 and return the previous state as a monadic value.
4350 @deffn {Monadic Procedure} state-pop
4351 Pop a value from the current state and return it as a monadic value.
4352 The state is assumed to be a list.
4355 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4356 Run monadic value @var{mval} starting with @var{state} as the initial
4357 state. Return two values: the resulting value, and the resulting state.
4360 The main interface to the store monad, provided by the @code{(guix
4361 store)} module, is as follows.
4363 @defvr {Scheme Variable} %store-monad
4364 The store monad---an alias for @var{%state-monad}.
4366 Values in the store monad encapsulate accesses to the store. When its
4367 effect is needed, a value of the store monad must be ``evaluated'' by
4368 passing it to the @code{run-with-store} procedure (see below.)
4371 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4372 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4373 open store connection.
4376 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4377 Return as a monadic value the absolute file name in the store of the file
4378 containing @var{text}, a string. @var{references} is a list of store items that the
4379 resulting text file refers to; it defaults to the empty list.
4382 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4383 [#:recursive? #t] [#:select? (const #t)]
4384 Return the name of @var{file} once interned in the store. Use
4385 @var{name} as its store name, or the basename of @var{file} if
4386 @var{name} is omitted.
4388 When @var{recursive?} is true, the contents of @var{file} are added
4389 recursively; if @var{file} designates a flat file and @var{recursive?}
4390 is true, its contents are added, and its permission bits are kept.
4392 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4393 @var{stat})} for each directory entry, where @var{file} is the entry's
4394 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4395 entries for which @var{select?} does not return true.
4397 The example below adds a file to the store, under two different names:
4400 (run-with-store (open-connection)
4401 (mlet %store-monad ((a (interned-file "README"))
4402 (b (interned-file "README" "LEGU-MIN")))
4403 (return (list a b))))
4405 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4410 The @code{(guix packages)} module exports the following package-related
4413 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4414 [#:system (%current-system)] [#:target #f] @
4417 value in the absolute file name of @var{file} within the @var{output}
4418 directory of @var{package}. When @var{file} is omitted, return the name
4419 of the @var{output} directory of @var{package}. When @var{target} is
4420 true, use it as a cross-compilation target triplet.
4423 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4424 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4425 @var{target} [@var{system}]
4426 Monadic version of @code{package-derivation} and
4427 @code{package-cross-derivation} (@pxref{Defining Packages}).
4432 @section G-Expressions
4434 @cindex G-expression
4435 @cindex build code quoting
4436 So we have ``derivations'', which represent a sequence of build actions
4437 to be performed to produce an item in the store (@pxref{Derivations}).
4438 These build actions are performed when asking the daemon to actually
4439 build the derivations; they are run by the daemon in a container
4440 (@pxref{Invoking guix-daemon}).
4442 @cindex strata of code
4443 It should come as no surprise that we like to write these build actions
4444 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4445 code@footnote{The term @dfn{stratum} in this context was coined by
4446 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4447 Kiselyov, who has written insightful
4448 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4449 on this topic}, refers to this kind of code generation as
4450 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4451 to the daemon, etc.---and the ``build code''---code that actually
4452 performs build actions, such as making directories, invoking
4453 @command{make}, etc.
4455 To describe a derivation and its build actions, one typically needs to
4456 embed build code inside host code. It boils down to manipulating build
4457 code as data, and the homoiconicity of Scheme---code has a direct
4458 representation as data---comes in handy for that. But we need more than
4459 the normal @code{quasiquote} mechanism in Scheme to construct build
4462 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4463 S-expressions adapted to build expressions. G-expressions, or
4464 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4465 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4466 @code{#$}, and @code{#$@@}), which are comparable to
4467 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4468 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4469 GNU Guile Reference Manual}). However, there are major differences:
4473 Gexps are meant to be written to a file and run or manipulated by other
4477 When a high-level object such as a package or derivation is unquoted
4478 inside a gexp, the result is as if its output file name had been
4482 Gexps carry information about the packages or derivations they refer to,
4483 and these dependencies are automatically added as inputs to the build
4484 processes that use them.
4487 @cindex lowering, of high-level objects in gexps
4488 This mechanism is not limited to package and derivation
4489 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4490 derivations or files in the store can be defined,
4491 such that these objects can also be inserted
4492 into gexps. For example, a useful type of high-level objects that can be
4493 inserted in a gexp is ``file-like objects'', which make it easy to
4494 add files to the store and to refer to them in
4495 derivations and such (see @code{local-file} and @code{plain-file}
4498 To illustrate the idea, here is an example of a gexp:
4505 (symlink (string-append #$coreutils "/bin/ls")
4509 This gexp can be passed to @code{gexp->derivation}; we obtain a
4510 derivation that builds a directory containing exactly one symlink to
4511 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4514 (gexp->derivation "the-thing" build-exp)
4517 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4518 substituted to the reference to the @var{coreutils} package in the
4519 actual build code, and @var{coreutils} is automatically made an input to
4520 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4521 output)}) is replaced by a string containing the directory name of the
4522 output of the derivation.
4524 @cindex cross compilation
4525 In a cross-compilation context, it is useful to distinguish between
4526 references to the @emph{native} build of a package---that can run on the
4527 host---versus references to cross builds of a package. To that end, the
4528 @code{#+} plays the same role as @code{#$}, but is a reference to a
4529 native package build:
4532 (gexp->derivation "vi"
4535 (system* (string-append #+coreutils "/bin/ln")
4537 (string-append #$emacs "/bin/emacs")
4538 (string-append #$output "/bin/vi")))
4539 #:target "mips64el-linux-gnu")
4543 In the example above, the native build of @var{coreutils} is used, so
4544 that @command{ln} can actually run on the host; but then the
4545 cross-compiled build of @var{emacs} is referenced.
4547 @cindex imported modules, for gexps
4548 @findex with-imported-modules
4549 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4550 able to use certain Guile modules from the ``host environment'' in the
4551 gexp, so those modules should be imported in the ``build environment''.
4552 The @code{with-imported-modules} form allows you to express that:
4555 (let ((build (with-imported-modules '((guix build utils))
4557 (use-modules (guix build utils))
4558 (mkdir-p (string-append #$output "/bin"))))))
4559 (gexp->derivation "empty-dir"
4562 (display "success!\n")
4567 In this example, the @code{(guix build utils)} module is automatically
4568 pulled into the isolated build environment of our gexp, such that
4569 @code{(use-modules (guix build utils))} works as expected.
4571 @cindex module closure
4572 @findex source-module-closure
4573 Usually you want the @emph{closure} of the module to be imported---i.e.,
4574 the module itself and all the modules it depends on---rather than just
4575 the module; failing to do that, attempts to use the module will fail
4576 because of missing dependent modules. The @code{source-module-closure}
4577 procedure computes the closure of a module by looking at its source file
4578 headers, which comes in handy in this case:
4581 (use-modules (guix modules)) ;for 'source-module-closure'
4583 (with-imported-modules (source-module-closure
4584 '((guix build utils)
4586 (gexp->derivation "something-with-vms"
4588 (use-modules (guix build utils)
4593 The syntactic form to construct gexps is summarized below.
4595 @deffn {Scheme Syntax} #~@var{exp}
4596 @deffnx {Scheme Syntax} (gexp @var{exp})
4597 Return a G-expression containing @var{exp}. @var{exp} may contain one
4598 or more of the following forms:
4602 @itemx (ungexp @var{obj})
4603 Introduce a reference to @var{obj}. @var{obj} may have one of the
4604 supported types, for example a package or a
4605 derivation, in which case the @code{ungexp} form is replaced by its
4606 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4608 If @var{obj} is a list, it is traversed and references to supported
4609 objects are substituted similarly.
4611 If @var{obj} is another gexp, its contents are inserted and its
4612 dependencies are added to those of the containing gexp.
4614 If @var{obj} is another kind of object, it is inserted as is.
4616 @item #$@var{obj}:@var{output}
4617 @itemx (ungexp @var{obj} @var{output})
4618 This is like the form above, but referring explicitly to the
4619 @var{output} of @var{obj}---this is useful when @var{obj} produces
4620 multiple outputs (@pxref{Packages with Multiple Outputs}).
4623 @itemx #+@var{obj}:output
4624 @itemx (ungexp-native @var{obj})
4625 @itemx (ungexp-native @var{obj} @var{output})
4626 Same as @code{ungexp}, but produces a reference to the @emph{native}
4627 build of @var{obj} when used in a cross compilation context.
4629 @item #$output[:@var{output}]
4630 @itemx (ungexp output [@var{output}])
4631 Insert a reference to derivation output @var{output}, or to the main
4632 output when @var{output} is omitted.
4634 This only makes sense for gexps passed to @code{gexp->derivation}.
4637 @itemx (ungexp-splicing @var{lst})
4638 Like the above, but splices the contents of @var{lst} inside the
4642 @itemx (ungexp-native-splicing @var{lst})
4643 Like the above, but refers to native builds of the objects listed in
4648 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4649 of the @code{gexp?} type (see below.)
4652 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4653 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4654 in their execution environment.
4656 Each item in @var{modules} can be the name of a module, such as
4657 @code{(guix build utils)}, or it can be a module name, followed by an
4658 arrow, followed by a file-like object:
4661 `((guix build utils)
4663 ((guix config) => ,(scheme-file "config.scm"
4664 #~(define-module @dots{}))))
4668 In the example above, the first two modules are taken from the search
4669 path, and the last one is created from the given file-like object.
4671 This form has @emph{lexical} scope: it has an effect on the gexps
4672 directly defined in @var{body}@dots{}, but not on those defined, say, in
4673 procedures called from @var{body}@dots{}.
4676 @deffn {Scheme Procedure} gexp? @var{obj}
4677 Return @code{#t} if @var{obj} is a G-expression.
4680 G-expressions are meant to be written to disk, either as code building
4681 some derivation, or as plain files in the store. The monadic procedures
4682 below allow you to do that (@pxref{The Store Monad}, for more
4683 information about monads.)
4685 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4686 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4687 [#:hash #f] [#:hash-algo #f] @
4688 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4689 [#:module-path @var{%load-path}] @
4690 [#:references-graphs #f] [#:allowed-references #f] @
4691 [#:disallowed-references #f] @
4692 [#:leaked-env-vars #f] @
4693 [#:script-name (string-append @var{name} "-builder")] @
4694 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4695 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4696 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4697 stored in a file called @var{script-name}. When @var{target} is true,
4698 it is used as the cross-compilation target triplet for packages referred
4701 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4703 make @var{modules} available in the evaluation context of @var{exp};
4704 @var{modules} is a list of names of Guile modules searched in
4705 @var{module-path} to be copied in the store, compiled, and made available in
4706 the load path during the execution of @var{exp}---e.g., @code{((guix
4707 build utils) (guix build gnu-build-system))}.
4709 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4712 When @var{references-graphs} is true, it must be a list of tuples of one of the
4716 (@var{file-name} @var{package})
4717 (@var{file-name} @var{package} @var{output})
4718 (@var{file-name} @var{derivation})
4719 (@var{file-name} @var{derivation} @var{output})
4720 (@var{file-name} @var{store-item})
4723 The right-hand-side of each element of @var{references-graphs} is automatically made
4724 an input of the build process of @var{exp}. In the build environment, each
4725 @var{file-name} contains the reference graph of the corresponding item, in a simple
4728 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4729 In the latter case, the list denotes store items that the result is allowed to
4730 refer to. Any reference to another store item will lead to a build error.
4731 Similarly for @var{disallowed-references}, which can list items that must not be
4732 referenced by the outputs.
4734 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4737 @cindex file-like objects
4738 The @code{local-file}, @code{plain-file}, @code{computed-file},
4739 @code{program-file}, and @code{scheme-file} procedures below return
4740 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4741 these objects lead to a file in the store. Consider this G-expression:
4744 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4745 #$(local-file "/tmp/my-nscd.conf"))
4748 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4749 to the store. Once expanded, for instance @i{via}
4750 @code{gexp->derivation}, the G-expression refers to that copy under
4751 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4752 does not have any effect on what the G-expression does.
4753 @code{plain-file} can be used similarly; it differs in that the file
4754 content is directly passed as a string.
4756 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4757 [#:recursive? #f] [#:select? (const #t)]
4758 Return an object representing local file @var{file} to add to the store; this
4759 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4760 up relative to the source file where this form appears. @var{file} will be added to
4761 the store under @var{name}--by default the base name of @var{file}.
4763 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4764 designates a flat file and @var{recursive?} is true, its contents are added, and its
4765 permission bits are kept.
4767 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4768 @var{stat})} for each directory entry, where @var{file} is the entry's
4769 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4770 entries for which @var{select?} does not return true.
4772 This is the declarative counterpart of the @code{interned-file} monadic
4773 procedure (@pxref{The Store Monad, @code{interned-file}}).
4776 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4777 Return an object representing a text file called @var{name} with the given
4778 @var{content} (a string) to be added to the store.
4780 This is the declarative counterpart of @code{text-file}.
4783 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4784 [#:options '(#:local-build? #t)]
4785 Return an object representing the store item @var{name}, a file or
4786 directory computed by @var{gexp}. @var{options}
4787 is a list of additional arguments to pass to @code{gexp->derivation}.
4789 This is the declarative counterpart of @code{gexp->derivation}.
4792 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4793 Return an executable script @var{name} that runs @var{exp} using
4794 @var{guile}, with @var{exp}'s imported modules in its search path.
4796 The example below builds a script that simply invokes the @command{ls}
4800 (use-modules (guix gexp) (gnu packages base))
4802 (gexp->script "list-files"
4803 #~(execl #$(file-append coreutils "/bin/ls")
4807 When ``running'' it through the store (@pxref{The Store Monad,
4808 @code{run-with-store}}), we obtain a derivation that produces an
4809 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4812 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4814 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4818 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4820 Return an object representing the executable store item @var{name} that
4821 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4824 This is the declarative counterpart of @code{gexp->script}.
4827 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4828 [#:set-load-path? #t]
4829 Return a derivation that builds a file @var{name} containing @var{exp}.
4830 When @var{set-load-path?} is true, emit code in the resulting file to
4831 set @code{%load-path} and @code{%load-compiled-path} to honor
4832 @var{exp}'s imported modules.
4834 The resulting file holds references to all the dependencies of @var{exp}
4835 or a subset thereof.
4838 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4839 Return an object representing the Scheme file @var{name} that contains
4842 This is the declarative counterpart of @code{gexp->file}.
4845 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4846 Return as a monadic value a derivation that builds a text file
4847 containing all of @var{text}. @var{text} may list, in addition to
4848 strings, objects of any type that can be used in a gexp: packages,
4849 derivations, local file objects, etc. The resulting store file holds
4850 references to all these.
4852 This variant should be preferred over @code{text-file} anytime the file
4853 to create will reference items from the store. This is typically the
4854 case when building a configuration file that embeds store file names,
4858 (define (profile.sh)
4859 ;; Return the name of a shell script in the store that
4860 ;; initializes the 'PATH' environment variable.
4861 (text-file* "profile.sh"
4862 "export PATH=" coreutils "/bin:"
4863 grep "/bin:" sed "/bin\n"))
4866 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4867 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4868 preventing them from being garbage-collected during its lifetime.
4871 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4872 Return an object representing store file @var{name} containing
4873 @var{text}. @var{text} is a sequence of strings and file-like objects,
4877 (mixed-text-file "profile"
4878 "export PATH=" coreutils "/bin:" grep "/bin")
4881 This is the declarative counterpart of @code{text-file*}.
4884 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4885 Return a file-like object that expands to the concatenation of @var{obj}
4886 and @var{suffix}, where @var{obj} is a lowerable object and each
4887 @var{suffix} is a string.
4889 As an example, consider this gexp:
4892 (gexp->script "run-uname"
4893 #~(system* #$(file-append coreutils
4897 The same effect could be achieved with:
4900 (gexp->script "run-uname"
4901 #~(system* (string-append #$coreutils
4905 There is one difference though: in the @code{file-append} case, the
4906 resulting script contains the absolute file name as a string, whereas in
4907 the second case, the resulting script contains a @code{(string-append
4908 @dots{})} expression to construct the file name @emph{at run time}.
4912 Of course, in addition to gexps embedded in ``host'' code, there are
4913 also modules containing build tools. To make it clear that they are
4914 meant to be used in the build stratum, these modules are kept in the
4915 @code{(guix build @dots{})} name space.
4917 @cindex lowering, of high-level objects in gexps
4918 Internally, high-level objects are @dfn{lowered}, using their compiler,
4919 to either derivations or store items. For instance, lowering a package
4920 yields a derivation, and lowering a @code{plain-file} yields a store
4921 item. This is achieved using the @code{lower-object} monadic procedure.
4923 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4925 Return as a value in @var{%store-monad} the derivation or store item
4926 corresponding to @var{obj} for @var{system}, cross-compiling for
4927 @var{target} if @var{target} is true. @var{obj} must be an object that
4928 has an associated gexp compiler, such as a @code{<package>}.
4932 @c *********************************************************************
4936 This section describes Guix command-line utilities. Some of them are
4937 primarily targeted at developers and users who write new package
4938 definitions, while others are more generally useful. They complement
4939 the Scheme programming interface of Guix in a convenient way.
4942 * Invoking guix build:: Building packages from the command line.
4943 * Invoking guix edit:: Editing package definitions.
4944 * Invoking guix download:: Downloading a file and printing its hash.
4945 * Invoking guix hash:: Computing the cryptographic hash of a file.
4946 * Invoking guix import:: Importing package definitions.
4947 * Invoking guix refresh:: Updating package definitions.
4948 * Invoking guix lint:: Finding errors in package definitions.
4949 * Invoking guix size:: Profiling disk usage.
4950 * Invoking guix graph:: Visualizing the graph of packages.
4951 * Invoking guix environment:: Setting up development environments.
4952 * Invoking guix publish:: Sharing substitutes.
4953 * Invoking guix challenge:: Challenging substitute servers.
4954 * Invoking guix copy:: Copying to and from a remote store.
4955 * Invoking guix container:: Process isolation.
4956 * Invoking guix weather:: Assessing substitute availability.
4959 @node Invoking guix build
4960 @section Invoking @command{guix build}
4962 @cindex package building
4963 @cindex @command{guix build}
4964 The @command{guix build} command builds packages or derivations and
4965 their dependencies, and prints the resulting store paths. Note that it
4966 does not modify the user's profile---this is the job of the
4967 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4968 it is mainly useful for distribution developers.
4970 The general syntax is:
4973 guix build @var{options} @var{package-or-derivation}@dots{}
4976 As an example, the following command builds the latest versions of Emacs
4977 and of Guile, displays their build logs, and finally displays the
4978 resulting directories:
4981 guix build emacs guile
4984 Similarly, the following command builds all the available packages:
4987 guix build --quiet --keep-going \
4988 `guix package -A | cut -f1,2 --output-delimiter=@@`
4991 @var{package-or-derivation} may be either the name of a package found in
4992 the software distribution such as @code{coreutils} or
4993 @code{coreutils@@8.20}, or a derivation such as
4994 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4995 package with the corresponding name (and optionally version) is searched
4996 for among the GNU distribution modules (@pxref{Package Modules}).
4998 Alternatively, the @code{--expression} option may be used to specify a
4999 Scheme expression that evaluates to a package; this is useful when
5000 disambiguating among several same-named packages or package variants is
5003 There may be zero or more @var{options}. The available options are
5004 described in the subsections below.
5007 * Common Build Options:: Build options for most commands.
5008 * Package Transformation Options:: Creating variants of packages.
5009 * Additional Build Options:: Options specific to 'guix build'.
5010 * Debugging Build Failures:: Real life packaging experience.
5013 @node Common Build Options
5014 @subsection Common Build Options
5016 A number of options that control the build process are common to
5017 @command{guix build} and other commands that can spawn builds, such as
5018 @command{guix package} or @command{guix archive}. These are the
5023 @item --load-path=@var{directory}
5024 @itemx -L @var{directory}
5025 Add @var{directory} to the front of the package module search path
5026 (@pxref{Package Modules}).
5028 This allows users to define their own packages and make them visible to
5029 the command-line tools.
5033 Keep the build tree of failed builds. Thus, if a build fails, its build
5034 tree is kept under @file{/tmp}, in a directory whose name is shown at
5035 the end of the build log. This is useful when debugging build issues.
5036 @xref{Debugging Build Failures}, for tips and tricks on how to debug
5041 Keep going when some of the derivations fail to build; return only once
5042 all the builds have either completed or failed.
5044 The default behavior is to stop as soon as one of the specified
5045 derivations has failed.
5049 Do not build the derivations.
5052 When substituting a pre-built binary fails, fall back to building
5055 @item --substitute-urls=@var{urls}
5056 @anchor{client-substitute-urls}
5057 Consider @var{urls} the whitespace-separated list of substitute source
5058 URLs, overriding the default list of URLs of @command{guix-daemon}
5059 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
5061 This means that substitutes may be downloaded from @var{urls}, provided
5062 they are signed by a key authorized by the system administrator
5063 (@pxref{Substitutes}).
5065 When @var{urls} is the empty string, substitutes are effectively
5068 @item --no-substitutes
5069 Do not use substitutes for build products. That is, always build things
5070 locally instead of allowing downloads of pre-built binaries
5071 (@pxref{Substitutes}).
5074 Do not ``graft'' packages. In practice, this means that package updates
5075 available as grafts are not applied. @xref{Security Updates}, for more
5076 information on grafts.
5078 @item --rounds=@var{n}
5079 Build each derivation @var{n} times in a row, and raise an error if
5080 consecutive build results are not bit-for-bit identical.
5082 This is a useful way to detect non-deterministic builds processes.
5083 Non-deterministic build processes are a problem because they make it
5084 practically impossible for users to @emph{verify} whether third-party
5085 binaries are genuine. @xref{Invoking guix challenge}, for more.
5087 Note that, currently, the differing build results are not kept around,
5088 so you will have to manually investigate in case of an error---e.g., by
5089 stashing one of the build results with @code{guix archive --export}
5090 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
5093 @item --no-build-hook
5094 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
5095 (@pxref{Daemon Offload Setup}). That is, always build things locally
5096 instead of offloading builds to remote machines.
5098 @item --max-silent-time=@var{seconds}
5099 When the build or substitution process remains silent for more than
5100 @var{seconds}, terminate it and report a build failure.
5102 By default, the daemon's setting is honored (@pxref{Invoking
5103 guix-daemon, @code{--max-silent-time}}).
5105 @item --timeout=@var{seconds}
5106 Likewise, when the build or substitution process lasts for more than
5107 @var{seconds}, terminate it and report a build failure.
5109 By default, the daemon's setting is honored (@pxref{Invoking
5110 guix-daemon, @code{--timeout}}).
5112 @item --verbosity=@var{level}
5113 Use the given verbosity level. @var{level} must be an integer between 0
5114 and 5; higher means more verbose output. Setting a level of 4 or more
5115 may be helpful when debugging setup issues with the build daemon.
5117 @item --cores=@var{n}
5119 Allow the use of up to @var{n} CPU cores for the build. The special
5120 value @code{0} means to use as many CPU cores as available.
5122 @item --max-jobs=@var{n}
5124 Allow at most @var{n} build jobs in parallel. @xref{Invoking
5125 guix-daemon, @code{--max-jobs}}, for details about this option and the
5126 equivalent @command{guix-daemon} option.
5130 Behind the scenes, @command{guix build} is essentially an interface to
5131 the @code{package-derivation} procedure of the @code{(guix packages)}
5132 module, and to the @code{build-derivations} procedure of the @code{(guix
5133 derivations)} module.
5135 In addition to options explicitly passed on the command line,
5136 @command{guix build} and other @command{guix} commands that support
5137 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
5139 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
5140 Users can define this variable to a list of command line options that
5141 will automatically be used by @command{guix build} and other
5142 @command{guix} commands that can perform builds, as in the example
5146 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
5149 These options are parsed independently, and the result is appended to
5150 the parsed command-line options.
5154 @node Package Transformation Options
5155 @subsection Package Transformation Options
5157 @cindex package variants
5158 Another set of command-line options supported by @command{guix build}
5159 and also @command{guix package} are @dfn{package transformation
5160 options}. These are options that make it possible to define @dfn{package
5161 variants}---for instance, packages built from different source code.
5162 This is a convenient way to create customized packages on the fly
5163 without having to type in the definitions of package variants
5164 (@pxref{Defining Packages}).
5168 @item --with-source=@var{source}
5169 Use @var{source} as the source of the corresponding package.
5170 @var{source} must be a file name or a URL, as for @command{guix
5171 download} (@pxref{Invoking guix download}).
5173 The ``corresponding package'' is taken to be the one specified on the
5174 command line the name of which matches the base of @var{source}---e.g.,
5175 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
5176 package is @code{guile}. Likewise, the version string is inferred from
5177 @var{source}; in the previous example, it is @code{2.0.10}.
5179 This option allows users to try out versions of packages other than the
5180 one provided by the distribution. The example below downloads
5181 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5182 the @code{ed} package:
5185 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5188 As a developer, @code{--with-source} makes it easy to test release
5192 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5195 @dots{} or to build from a checkout in a pristine environment:
5198 $ git clone git://git.sv.gnu.org/guix.git
5199 $ guix build guix --with-source=./guix
5202 @item --with-input=@var{package}=@var{replacement}
5203 Replace dependency on @var{package} by a dependency on
5204 @var{replacement}. @var{package} must be a package name, and
5205 @var{replacement} must be a package specification such as @code{guile}
5206 or @code{guile@@1.8}.
5208 For instance, the following command builds Guix, but replaces its
5209 dependency on the current stable version of Guile with a dependency on
5210 the legacy version of Guile, @code{guile@@2.0}:
5213 guix build --with-input=guile=guile@@2.0 guix
5216 This is a recursive, deep replacement. So in this example, both
5217 @code{guix} and its dependency @code{guile-json} (which also depends on
5218 @code{guile}) get rebuilt against @code{guile@@2.0}.
5220 This is implemented using the @code{package-input-rewriting} Scheme
5221 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5223 @item --with-graft=@var{package}=@var{replacement}
5224 This is similar to @code{--with-input} but with an important difference:
5225 instead of rebuilding the whole dependency chain, @var{replacement} is
5226 built and then @dfn{grafted} onto the binaries that were initially
5227 referring to @var{package}. @xref{Security Updates}, for more
5228 information on grafts.
5230 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5231 and all its dependencies, replacing references to the version of GnuTLS
5232 they currently refer to:
5235 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5238 This has the advantage of being much faster than rebuilding everything.
5239 But there is a caveat: it works if and only if @var{package} and
5240 @var{replacement} are strictly compatible---for example, if they provide
5241 a library, the application binary interface (ABI) of those libraries
5242 must be compatible. If @var{replacement} is somehow incompatible with
5243 @var{package}, then the resulting package may be unusable. Use with
5248 @node Additional Build Options
5249 @subsection Additional Build Options
5251 The command-line options presented below are specific to @command{guix
5258 Build quietly, without displaying the build log. Upon completion, the
5259 build log is kept in @file{/var} (or similar) and can always be
5260 retrieved using the @option{--log-file} option.
5262 @item --file=@var{file}
5263 @itemx -f @var{file}
5265 Build the package or derivation that the code within @var{file}
5268 As an example, @var{file} might contain a package definition like this
5269 (@pxref{Defining Packages}):
5272 @verbatiminclude package-hello.scm
5275 @item --expression=@var{expr}
5276 @itemx -e @var{expr}
5277 Build the package or derivation @var{expr} evaluates to.
5279 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5280 guile-1.8)}, which unambiguously designates this specific variant of
5281 version 1.8 of Guile.
5283 Alternatively, @var{expr} may be a G-expression, in which case it is used
5284 as a build program passed to @code{gexp->derivation}
5285 (@pxref{G-Expressions}).
5287 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5288 (@pxref{The Store Monad}). The procedure must return a derivation as a
5289 monadic value, which is then passed through @code{run-with-store}.
5293 Build the source derivations of the packages, rather than the packages
5296 For instance, @code{guix build -S gcc} returns something like
5297 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5300 The returned source tarball is the result of applying any patches and
5301 code snippets specified in the package @code{origin} (@pxref{Defining
5305 Fetch and return the source of @var{package-or-derivation} and all their
5306 dependencies, recursively. This is a handy way to obtain a local copy
5307 of all the source code needed to build @var{packages}, allowing you to
5308 eventually build them even without network access. It is an extension
5309 of the @code{--source} option and can accept one of the following
5310 optional argument values:
5314 This value causes the @code{--sources} option to behave in the same way
5315 as the @code{--source} option.
5318 Build the source derivations of all packages, including any source that
5319 might be listed as @code{inputs}. This is the default value.
5322 $ guix build --sources tzdata
5323 The following derivations will be built:
5324 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5325 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5329 Build the source derivations of all packages, as well of all transitive
5330 inputs to the packages. This can be used e.g. to
5331 prefetch package source for later offline building.
5334 $ guix build --sources=transitive tzdata
5335 The following derivations will be built:
5336 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5337 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5338 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5339 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5340 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5341 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5347 @item --system=@var{system}
5348 @itemx -s @var{system}
5349 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5350 the system type of the build host.
5352 An example use of this is on Linux-based systems, which can emulate
5353 different personalities. For instance, passing
5354 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5355 to build packages in a complete 32-bit environment.
5357 @item --target=@var{triplet}
5358 @cindex cross-compilation
5359 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5360 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5361 configuration triplets,, autoconf, Autoconf}).
5363 @anchor{build-check}
5365 @cindex determinism, checking
5366 @cindex reproducibility, checking
5367 Rebuild @var{package-or-derivation}, which are already available in the
5368 store, and raise an error if the build results are not bit-for-bit
5371 This mechanism allows you to check whether previously installed
5372 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5373 of a package is deterministic. @xref{Invoking guix challenge}, for more
5374 background information and tools.
5376 When used in conjunction with @option{--keep-failed}, the differing
5377 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5378 This makes it easy to look for differences between the two results.
5381 @cindex repairing store items
5382 @cindex corruption, recovering from
5383 Attempt to repair the specified store items, if they are corrupt, by
5384 re-downloading or rebuilding them.
5386 This operation is not atomic and thus restricted to @code{root}.
5390 Return the derivation paths, not the output paths, of the given
5393 @item --root=@var{file}
5394 @itemx -r @var{file}
5395 Make @var{file} a symlink to the result, and register it as a garbage
5399 Return the build log file names or URLs for the given
5400 @var{package-or-derivation}, or raise an error if build logs are
5403 This works regardless of how packages or derivations are specified. For
5404 instance, the following invocations are equivalent:
5407 guix build --log-file `guix build -d guile`
5408 guix build --log-file `guix build guile`
5409 guix build --log-file guile
5410 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5413 If a log is unavailable locally, and unless @code{--no-substitutes} is
5414 passed, the command looks for a corresponding log on one of the
5415 substitute servers (as specified with @code{--substitute-urls}.)
5417 So for instance, imagine you want to see the build log of GDB on MIPS,
5418 but you are actually on an @code{x86_64} machine:
5421 $ guix build --log-file gdb -s mips64el-linux
5422 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5425 You can freely access a huge library of build logs!
5428 @node Debugging Build Failures
5429 @subsection Debugging Build Failures
5431 @cindex build failures, debugging
5432 When defining a new package (@pxref{Defining Packages}), you will
5433 probably find yourself spending some time debugging and tweaking the
5434 build until it succeeds. To do that, you need to operate the build
5435 commands yourself in an environment as close as possible to the one the
5438 To that end, the first thing to do is to use the @option{--keep-failed}
5439 or @option{-K} option of @command{guix build}, which will keep the
5440 failed build tree in @file{/tmp} or whatever directory you specified as
5441 @code{TMPDIR} (@pxref{Invoking guix build, @code{--keep-failed}}).
5443 From there on, you can @command{cd} to the failed build tree and source
5444 the @file{environment-variables} file, which contains all the
5445 environment variable definitions that were in place when the build
5446 failed. So let's say you're debugging a build failure in package
5447 @code{foo}; a typical session would look like this:
5451 @dots{} @i{build fails}
5452 $ cd /tmp/guix-build-foo.drv-0
5453 $ source ./environment-variables
5457 Now, you can invoke commands as if you were the daemon (almost) and
5458 troubleshoot your build process.
5460 Sometimes it happens that, for example, a package's tests pass when you
5461 run them manually but they fail when the daemon runs them. This can
5462 happen because the daemon runs builds in containers where, unlike in our
5463 environment above, network access is missing, @file{/bin/sh} does not
5464 exist, etc. (@pxref{Build Environment Setup}).
5466 In such cases, you may need to run inspect the build process from within
5467 a container similar to the one the build daemon creates:
5472 $ cd /tmp/guix-build-foo.drv-0
5473 $ guix environment --no-grafts -C foo --ad-hoc strace gdb
5474 [env]# source ./environment-variables
5478 Here, @command{guix environment -C} creates a container and spawns a new
5479 shell in it (@pxref{Invoking guix environment}). The @command{--ad-hoc
5480 strace gdb} part adds the @command{strace} and @command{gdb} commands to
5481 the container, which would may find handy while debugging. The
5482 @option{--no-grafts} option makes sure we get the exact same
5483 environment, with ungrafted packages (@pxref{Security Updates}, for more
5486 To get closer to a container like that used by the build daemon, we can
5487 remove @file{/bin/sh}:
5493 (Don't worry, this is harmless: this is all happening in the throw-away
5494 container created by @command{guix environment}.)
5496 The @command{strace} command is probably not in the search path, but we
5500 [env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check
5503 In this way, not only you will have reproduced the environment variables
5504 the daemon uses, you will also be running the build process in a container
5505 similar to the one the daemon uses.
5508 @node Invoking guix edit
5509 @section Invoking @command{guix edit}
5511 @cindex @command{guix edit}
5512 @cindex package definition, editing
5513 So many packages, so many source files! The @command{guix edit} command
5514 facilitates the life of users and packagers by pointing their editor at
5515 the source file containing the definition of the specified packages.
5519 guix edit gcc@@4.9 vim
5523 launches the program specified in the @code{VISUAL} or in the
5524 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5527 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5528 have created your own packages on @code{GUIX_PACKAGE_PATH}
5529 (@pxref{Defining Packages}), you will be able to edit the package
5530 recipes. Otherwise, you will be able to examine the read-only recipes
5531 for packages currently in the store.
5534 @node Invoking guix download
5535 @section Invoking @command{guix download}
5537 @cindex @command{guix download}
5538 @cindex downloading package sources
5539 When writing a package definition, developers typically need to download
5540 a source tarball, compute its SHA256 hash, and write that
5541 hash in the package definition (@pxref{Defining Packages}). The
5542 @command{guix download} tool helps with this task: it downloads a file
5543 from the given URI, adds it to the store, and prints both its file name
5544 in the store and its SHA256 hash.
5546 The fact that the downloaded file is added to the store saves bandwidth:
5547 when the developer eventually tries to build the newly defined package
5548 with @command{guix build}, the source tarball will not have to be
5549 downloaded again because it is already in the store. It is also a
5550 convenient way to temporarily stash files, which may be deleted
5551 eventually (@pxref{Invoking guix gc}).
5553 The @command{guix download} command supports the same URIs as used in
5554 package definitions. In particular, it supports @code{mirror://} URIs.
5555 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5556 Guile bindings for GnuTLS are available in the user's environment; when
5557 they are not available, an error is raised. @xref{Guile Preparations,
5558 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5559 GnuTLS-Guile}, for more information.
5561 @command{guix download} verifies HTTPS server certificates by loading
5562 the certificates of X.509 authorities from the directory pointed to by
5563 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5564 Certificates}), unless @option{--no-check-certificate} is used.
5566 The following options are available:
5569 @item --format=@var{fmt}
5571 Write the hash in the format specified by @var{fmt}. For more
5572 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5574 @item --no-check-certificate
5575 Do not validate the X.509 certificates of HTTPS servers.
5577 When using this option, you have @emph{absolutely no guarantee} that you
5578 are communicating with the authentic server responsible for the given
5579 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5581 @item --output=@var{file}
5582 @itemx -o @var{file}
5583 Save the downloaded file to @var{file} instead of adding it to the
5587 @node Invoking guix hash
5588 @section Invoking @command{guix hash}
5590 @cindex @command{guix hash}
5591 The @command{guix hash} command computes the SHA256 hash of a file.
5592 It is primarily a convenience tool for anyone contributing to the
5593 distribution: it computes the cryptographic hash of a file, which can be
5594 used in the definition of a package (@pxref{Defining Packages}).
5596 The general syntax is:
5599 guix hash @var{option} @var{file}
5602 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5603 hash of data read from standard input. @command{guix hash} has the
5608 @item --format=@var{fmt}
5610 Write the hash in the format specified by @var{fmt}.
5612 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5613 (@code{hex} and @code{hexadecimal} can be used as well).
5615 If the @option{--format} option is not specified, @command{guix hash}
5616 will output the hash in @code{nix-base32}. This representation is used
5617 in the definitions of packages.
5621 Compute the hash on @var{file} recursively.
5623 In this case, the hash is computed on an archive containing @var{file},
5624 including its children if it is a directory. Some of the metadata of
5625 @var{file} is part of the archive; for instance, when @var{file} is a
5626 regular file, the hash is different depending on whether @var{file} is
5627 executable or not. Metadata such as time stamps has no impact on the
5628 hash (@pxref{Invoking guix archive}).
5629 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5634 When combined with @option{--recursive}, exclude version control system
5635 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5638 As an example, here is how you would compute the hash of a Git checkout,
5639 which is useful when using the @code{git-fetch} method (@pxref{origin
5643 $ git clone http://example.org/foo.git
5649 @node Invoking guix import
5650 @section Invoking @command{guix import}
5652 @cindex importing packages
5653 @cindex package import
5654 @cindex package conversion
5655 @cindex Invoking @command{guix import}
5656 The @command{guix import} command is useful for people who would like to
5657 add a package to the distribution with as little work as
5658 possible---a legitimate demand. The command knows of a few
5659 repositories from which it can ``import'' package metadata. The result
5660 is a package definition, or a template thereof, in the format we know
5661 (@pxref{Defining Packages}).
5663 The general syntax is:
5666 guix import @var{importer} @var{options}@dots{}
5669 @var{importer} specifies the source from which to import package
5670 metadata, and @var{options} specifies a package identifier and other
5671 options specific to @var{importer}. Currently, the available
5676 Import metadata for the given GNU package. This provides a template
5677 for the latest version of that GNU package, including the hash of its
5678 source tarball, and its canonical synopsis and description.
5680 Additional information such as the package dependencies and its
5681 license needs to be figured out manually.
5683 For example, the following command returns a package definition for
5687 guix import gnu hello
5690 Specific command-line options are:
5693 @item --key-download=@var{policy}
5694 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5695 keys when verifying the package signature. @xref{Invoking guix
5696 refresh, @code{--key-download}}.
5701 Import metadata from the @uref{https://pypi.python.org/, Python Package
5702 Index}@footnote{This functionality requires Guile-JSON to be installed.
5703 @xref{Requirements}.}. Information is taken from the JSON-formatted
5704 description available at @code{pypi.python.org} and usually includes all
5705 the relevant information, including package dependencies. For maximum
5706 efficiency, it is recommended to install the @command{unzip} utility, so
5707 that the importer can unzip Python wheels and gather data from them.
5709 The command below imports metadata for the @code{itsdangerous} Python
5713 guix import pypi itsdangerous
5718 Import metadata from @uref{https://rubygems.org/,
5719 RubyGems}@footnote{This functionality requires Guile-JSON to be
5720 installed. @xref{Requirements}.}. Information is taken from the
5721 JSON-formatted description available at @code{rubygems.org} and includes
5722 most relevant information, including runtime dependencies. There are
5723 some caveats, however. The metadata doesn't distinguish between
5724 synopses and descriptions, so the same string is used for both fields.
5725 Additionally, the details of non-Ruby dependencies required to build
5726 native extensions is unavailable and left as an exercise to the
5729 The command below imports metadata for the @code{rails} Ruby package:
5732 guix import gem rails
5737 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5738 functionality requires Guile-JSON to be installed.
5739 @xref{Requirements}.}.
5740 Information is taken from the JSON-formatted metadata provided through
5741 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5742 relevant information, such as module dependencies. License information
5743 should be checked closely. If Perl is available in the store, then the
5744 @code{corelist} utility will be used to filter core modules out of the
5745 list of dependencies.
5747 The command command below imports metadata for the @code{Acme::Boolean}
5751 guix import cpan Acme::Boolean
5756 @cindex Bioconductor
5757 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5758 central repository for the @uref{http://r-project.org, GNU@tie{}R
5759 statistical and graphical environment}.
5761 Information is extracted from the @code{DESCRIPTION} file of the package.
5763 The command command below imports metadata for the @code{Cairo}
5767 guix import cran Cairo
5770 When @code{--recursive} is added, the importer will traverse the
5771 dependency graph of the given upstream package recursively and generate
5772 package expressions for all those packages that are not yet in Guix.
5774 When @code{--archive=bioconductor} is added, metadata is imported from
5775 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5776 packages for for the analysis and comprehension of high-throughput
5777 genomic data in bioinformatics.
5779 Information is extracted from the @code{DESCRIPTION} file of a package
5780 published on the web interface of the Bioconductor SVN repository.
5782 The command below imports metadata for the @code{GenomicRanges}
5786 guix import cran --archive=bioconductor GenomicRanges
5792 Import metadata from @uref{http://www.ctan.org/, CTAN}, the
5793 comprehensive TeX archive network for TeX packages that are part of the
5794 @uref{https://www.tug.org/texlive/, TeX Live distribution}.
5796 Information about the package is obtained through the XML API provided
5797 by CTAN, while the source code is downloaded from the SVN repository of
5798 the Tex Live project. This is done because the CTAN does not keep
5801 The command command below imports metadata for the @code{fontspec}
5805 guix import texlive fontspec
5808 When @code{--archive=DIRECTORY} is added, the source code is downloaded
5809 not from the @file{latex} sub-directory of the @file{texmf-dist/source}
5810 tree in the TeX Live SVN repository, but from the specified sibling
5811 directory under the same root.
5813 The command below imports metadata for the @code{ifxetex} package from
5814 CTAN while fetching the sources from the directory
5815 @file{texmf/source/generic}:
5818 guix import texlive --archive=generic ifxetex
5822 Import metadata from a local copy of the source of the
5823 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5824 relies on the @command{nix-instantiate} command of
5825 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5826 typically written in a mixture of Nix-language and Bash code. This
5827 command only imports the high-level package structure that is written in
5828 the Nix language. It normally includes all the basic fields of a
5831 When importing a GNU package, the synopsis and descriptions are replaced
5832 by their canonical upstream variant.
5834 Usually, you will first need to do:
5837 export NIX_REMOTE=daemon
5841 so that @command{nix-instantiate} does not try to open the Nix database.
5843 As an example, the command below imports the package definition of
5844 LibreOffice (more precisely, it imports the definition of the package
5845 bound to the @code{libreoffice} top-level attribute):
5848 guix import nix ~/path/to/nixpkgs libreoffice
5853 Import metadata from the Haskell community's central package archive
5854 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5855 Cabal files and includes all the relevant information, including package
5858 Specific command-line options are:
5863 Read a Cabal file from standard input.
5864 @item --no-test-dependencies
5866 Do not include dependencies required only by the test suites.
5867 @item --cabal-environment=@var{alist}
5868 @itemx -e @var{alist}
5869 @var{alist} is a Scheme alist defining the environment in which the
5870 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5871 @code{arch}, @code{impl} and a string representing the name of a flag.
5872 The value associated with a flag has to be either the symbol
5873 @code{true} or @code{false}. The value associated with other keys
5874 has to conform to the Cabal file format definition. The default value
5875 associated with the keys @code{os}, @code{arch} and @code{impl} is
5876 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5879 The command below imports metadata for the latest version of the
5880 @code{HTTP} Haskell package without including test dependencies and
5881 specifying the value of the flag @samp{network-uri} as @code{false}:
5884 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5887 A specific package version may optionally be specified by following the
5888 package name by an at-sign and a version number as in the following example:
5891 guix import hackage mtl@@2.1.3.1
5896 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5897 It takes a package name, looks up the package version included in a
5898 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5899 release and uses the @code{hackage} importer to retrieve its metadata.
5900 Note that it is up to you to select an LTS release compatible with the
5901 GHC compiler used by Guix.
5903 Specific command-line options are:
5906 @item --no-test-dependencies
5908 Do not include dependencies required only by the test suites.
5909 @item --lts-version=@var{version}
5910 @itemx -r @var{version}
5911 @var{version} is the desired LTS release version. If omitted the latest
5915 The command below imports metadata for the @code{HTTP} Haskell package
5916 included in the LTS Stackage release version 7.18:
5919 guix import stackage --lts-version=7.18 HTTP
5924 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5925 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5927 Specific command-line options are:
5930 @item --archive=@var{repo}
5931 @itemx -a @var{repo}
5932 @var{repo} identifies the archive repository from which to retrieve the
5933 information. Currently the supported repositories and their identifiers
5937 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5938 identifier. This is the default.
5940 Packages from @code{elpa.gnu.org} are signed with one of the keys
5941 contained in the GnuPG keyring at
5942 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5943 @code{emacs} package (@pxref{Package Installation, ELPA package
5944 signatures,, emacs, The GNU Emacs Manual}).
5947 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5948 @code{melpa-stable} identifier.
5951 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5958 Import metadata from the crates.io Rust package repository
5959 @uref{https://crates.io, crates.io}.
5962 The structure of the @command{guix import} code is modular. It would be
5963 useful to have more importers for other package formats, and your help
5964 is welcome here (@pxref{Contributing}).
5966 @node Invoking guix refresh
5967 @section Invoking @command{guix refresh}
5969 @cindex @command {guix refresh}
5970 The primary audience of the @command{guix refresh} command is developers
5971 of the GNU software distribution. By default, it reports any packages
5972 provided by the distribution that are outdated compared to the latest
5973 upstream version, like this:
5977 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5978 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5981 Alternately, one can specify packages to consider, in which case a
5982 warning is emitted for packages that lack an updater:
5985 $ guix refresh coreutils guile guile-ssh
5986 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5987 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5990 @command{guix refresh} browses the upstream repository of each package and determines
5991 the highest version number of the releases therein. The command
5992 knows how to update specific types of packages: GNU packages, ELPA
5993 packages, etc.---see the documentation for @option{--type} below. There
5994 are many packages, though, for which it lacks a method to determine
5995 whether a new upstream release is available. However, the mechanism is
5996 extensible, so feel free to get in touch with us to add a new method!
5998 When passed @code{--update}, it modifies distribution source files to
5999 update the version numbers and source tarball hashes of those package
6000 recipes (@pxref{Defining Packages}). This is achieved by downloading
6001 each package's latest source tarball and its associated OpenPGP
6002 signature, authenticating the downloaded tarball against its signature
6003 using @command{gpg}, and finally computing its hash. When the public
6004 key used to sign the tarball is missing from the user's keyring, an
6005 attempt is made to automatically retrieve it from a public key server;
6006 when this is successful, the key is added to the user's keyring; otherwise,
6007 @command{guix refresh} reports an error.
6009 The following options are supported:
6013 @item --expression=@var{expr}
6014 @itemx -e @var{expr}
6015 Consider the package @var{expr} evaluates to.
6017 This is useful to precisely refer to a package, as in this example:
6020 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
6023 This command lists the dependents of the ``final'' libc (essentially all
6028 Update distribution source files (package recipes) in place. This is
6029 usually run from a checkout of the Guix source tree (@pxref{Running
6030 Guix Before It Is Installed}):
6033 $ ./pre-inst-env guix refresh -s non-core -u
6036 @xref{Defining Packages}, for more information on package definitions.
6038 @item --select=[@var{subset}]
6039 @itemx -s @var{subset}
6040 Select all the packages in @var{subset}, one of @code{core} or
6043 The @code{core} subset refers to all the packages at the core of the
6044 distribution---i.e., packages that are used to build ``everything
6045 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
6046 changing one of these packages in the distribution entails a rebuild of
6047 all the others. Thus, such updates are an inconvenience to users in
6048 terms of build time or bandwidth used to achieve the upgrade.
6050 The @code{non-core} subset refers to the remaining packages. It is
6051 typically useful in cases where an update of the core packages would be
6054 @item --manifest=@var{file}
6055 @itemx -m @var{file}
6056 Select all the packages from the manifest in @var{file}. This is useful to
6057 check if any packages of the user manifest can be updated.
6059 @item --type=@var{updater}
6060 @itemx -t @var{updater}
6061 Select only packages handled by @var{updater} (may be a comma-separated
6062 list of updaters). Currently, @var{updater} may be one of:
6066 the updater for GNU packages;
6068 the updater for GNOME packages;
6070 the updater for KDE packages;
6072 the updater for X.org packages;
6074 the updater for packages hosted on kernel.org;
6076 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
6078 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
6080 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
6082 the updater for @uref{http://www.cpan.org/, CPAN} packages;
6084 the updater for @uref{https://pypi.python.org, PyPI} packages.
6086 the updater for @uref{https://rubygems.org, RubyGems} packages.
6088 the updater for @uref{https://github.com, GitHub} packages.
6090 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
6092 the updater for @uref{https://www.stackage.org, Stackage} packages.
6094 the updater for @uref{https://crates.io, Crates} packages.
6097 For instance, the following command only checks for updates of Emacs
6098 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
6101 $ guix refresh --type=elpa,cran
6102 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
6103 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
6108 In addition, @command{guix refresh} can be passed one or more package
6109 names, as in this example:
6112 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
6116 The command above specifically updates the @code{emacs} and
6117 @code{idutils} packages. The @code{--select} option would have no
6118 effect in this case.
6120 When considering whether to upgrade a package, it is sometimes
6121 convenient to know which packages would be affected by the upgrade and
6122 should be checked for compatibility. For this the following option may
6123 be used when passing @command{guix refresh} one or more package names:
6127 @item --list-updaters
6129 List available updaters and exit (see @option{--type} above.)
6131 For each updater, display the fraction of packages it covers; at the
6132 end, display the fraction of packages covered by all these updaters.
6134 @item --list-dependent
6136 List top-level dependent packages that would need to be rebuilt as a
6137 result of upgrading one or more packages.
6139 @xref{Invoking guix graph, the @code{reverse-package} type of
6140 @command{guix graph}}, for information on how to visualize the list of
6141 dependents of a package.
6145 Be aware that the @code{--list-dependent} option only
6146 @emph{approximates} the rebuilds that would be required as a result of
6147 an upgrade. More rebuilds might be required under some circumstances.
6150 $ guix refresh --list-dependent flex
6151 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
6152 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
6155 The command above lists a set of packages that could be built to check
6156 for compatibility with an upgraded @code{flex} package.
6158 The following options can be used to customize GnuPG operation:
6162 @item --gpg=@var{command}
6163 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
6164 for in @code{$PATH}.
6166 @item --key-download=@var{policy}
6167 Handle missing OpenPGP keys according to @var{policy}, which may be one
6172 Always download missing OpenPGP keys from the key server, and add them
6173 to the user's GnuPG keyring.
6176 Never try to download missing OpenPGP keys. Instead just bail out.
6179 When a package signed with an unknown OpenPGP key is encountered, ask
6180 the user whether to download it or not. This is the default behavior.
6183 @item --key-server=@var{host}
6184 Use @var{host} as the OpenPGP key server when importing a public key.
6188 The @code{github} updater uses the
6189 @uref{https://developer.github.com/v3/, GitHub API} to query for new
6190 releases. When used repeatedly e.g. when refreshing all packages,
6191 GitHub will eventually refuse to answer any further API requests. By
6192 default 60 API requests per hour are allowed, and a full refresh on all
6193 GitHub packages in Guix requires more than this. Authentication with
6194 GitHub through the use of an API token alleviates these limits. To use
6195 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
6196 token procured from @uref{https://github.com/settings/tokens} or
6200 @node Invoking guix lint
6201 @section Invoking @command{guix lint}
6203 @cindex @command{guix lint}
6204 @cindex package, checking for errors
6205 The @command{guix lint} command is meant to help package developers avoid
6206 common errors and use a consistent style. It runs a number of checks on
6207 a given set of packages in order to find common mistakes in their
6208 definitions. Available @dfn{checkers} include (see
6209 @code{--list-checkers} for a complete list):
6214 Validate certain typographical and stylistic rules about package
6215 descriptions and synopses.
6217 @item inputs-should-be-native
6218 Identify inputs that should most likely be native inputs.
6223 @itemx source-file-name
6224 Probe @code{home-page} and @code{source} URLs and report those that are
6225 invalid. Suggest a @code{mirror://} URL when applicable. Check that
6226 the source file name is meaningful, e.g. is not
6227 just a version number or ``git-checkout'', without a declared
6228 @code{file-name} (@pxref{origin Reference}).
6231 @cindex security vulnerabilities
6232 @cindex CVE, Common Vulnerabilities and Exposures
6233 Report known vulnerabilities found in the Common Vulnerabilities and
6234 Exposures (CVE) databases of the current and past year
6235 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
6238 To view information about a particular vulnerability, visit pages such as:
6242 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
6244 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
6248 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
6249 @code{CVE-2015-7554}.
6251 Package developers can specify in package recipes the
6252 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
6253 name and version of the package when they differ from the name that Guix
6254 uses, as in this example:
6260 ;; CPE calls this package "grub2".
6261 (properties '((cpe-name . "grub2"))))
6265 Warn about obvious source code formatting issues: trailing white space,
6266 use of tabulations, etc.
6269 The general syntax is:
6272 guix lint @var{options} @var{package}@dots{}
6275 If no package is given on the command line, then all packages are checked.
6276 The @var{options} may be zero or more of the following:
6279 @item --list-checkers
6281 List and describe all the available checkers that will be run on packages
6286 Only enable the checkers specified in a comma-separated list using the
6287 names returned by @code{--list-checkers}.
6291 @node Invoking guix size
6292 @section Invoking @command{guix size}
6295 @cindex package size
6297 @cindex @command{guix size}
6298 The @command{guix size} command helps package developers profile the
6299 disk usage of packages. It is easy to overlook the impact of an
6300 additional dependency added to a package, or the impact of using a
6301 single output for a package that could easily be split (@pxref{Packages
6302 with Multiple Outputs}). Such are the typical issues that
6303 @command{guix size} can highlight.
6305 The command can be passed a package specification such as @code{gcc@@4.8}
6306 or @code{guile:debug}, or a file name in the store. Consider this
6310 $ guix size coreutils
6311 store item total self
6312 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6313 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6314 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6315 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6316 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6317 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6321 The store items listed here constitute the @dfn{transitive closure} of
6322 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6323 would be returned by:
6326 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6329 Here the output shows three columns next to store items. The first column,
6330 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6331 the store item---that is, its own size plus the size of all its
6332 dependencies. The next column, labeled ``self'', shows the size of the
6333 item itself. The last column shows the ratio of the size of the item
6334 itself to the space occupied by all the items listed here.
6336 In this example, we see that the closure of Coreutils weighs in at
6337 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6338 large fraction of the closure is not a problem @i{per se} because it is
6339 always available on the system anyway.)
6341 When the package passed to @command{guix size} is available in the
6342 store, @command{guix size} queries the daemon to determine its
6343 dependencies, and measures its size in the store, similar to @command{du
6344 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6347 When the given package is @emph{not} in the store, @command{guix size}
6348 reports information based on the available substitutes
6349 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6350 store items that are not even on disk, only available remotely.
6352 You can also specify several package names:
6355 $ guix size coreutils grep sed bash
6356 store item total self
6357 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6358 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6359 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6360 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6366 In this example we see that the combination of the four packages takes
6367 102.3@tie{}MiB in total, which is much less than the sum of each closure
6368 since they have a lot of dependencies in common.
6370 The available options are:
6374 @item --substitute-urls=@var{urls}
6375 Use substitute information from @var{urls}.
6376 @xref{client-substitute-urls, the same option for @code{guix build}}.
6378 @item --sort=@var{key}
6379 Sort lines according to @var{key}, one of the following options:
6383 the total size of the item's closure (the default);
6385 the size of each item.
6388 @item --map-file=@var{file}
6389 Write a graphical map of disk usage in PNG format to @var{file}.
6391 For the example above, the map looks like this:
6393 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6394 produced by @command{guix size}}
6396 This option requires that
6397 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6398 installed and visible in Guile's module search path. When that is not
6399 the case, @command{guix size} fails as it tries to load it.
6401 @item --system=@var{system}
6402 @itemx -s @var{system}
6403 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6407 @node Invoking guix graph
6408 @section Invoking @command{guix graph}
6411 @cindex @command{guix graph}
6412 @cindex package dependencies
6413 Packages and their dependencies form a @dfn{graph}, specifically a
6414 directed acyclic graph (DAG). It can quickly become difficult to have a
6415 mental model of the package DAG, so the @command{guix graph} command
6416 provides a visual representation of the DAG. By default,
6417 @command{guix graph} emits a DAG representation in the input format of
6418 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6419 directly to the @command{dot} command of Graphviz. It can also emit an
6420 HTML page with embedded JavaScript code to display a ``chord diagram''
6421 in a Web browser, using the @uref{https://d3js.org/, d3.js} library, or
6422 emit Cypher queries to construct a graph in a graph database supporting
6423 the @uref{http://www.opencypher.org/, openCypher} query language.
6424 The general syntax is:
6427 guix graph @var{options} @var{package}@dots{}
6430 For example, the following command generates a PDF file representing the
6431 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6435 guix graph coreutils | dot -Tpdf > dag.pdf
6438 The output looks like this:
6440 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6442 Nice little graph, no?
6444 But there is more than one graph! The one above is concise: it is the
6445 graph of package objects, omitting implicit inputs such as GCC, libc,
6446 grep, etc. It is often useful to have such a concise graph, but
6447 sometimes one may want to see more details. @command{guix graph} supports
6448 several types of graphs, allowing you to choose the level of detail:
6452 This is the default type used in the example above. It shows the DAG of
6453 package objects, excluding implicit dependencies. It is concise, but
6454 filters out many details.
6456 @item reverse-package
6457 This shows the @emph{reverse} DAG of packages. For example:
6460 guix graph --type=reverse-package ocaml
6463 ... yields the graph of packages that depend on OCaml.
6465 Note that for core packages this can yield huge graphs. If all you want
6466 is to know the number of packages that depend on a given package, use
6467 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6468 @option{--list-dependent}}).
6471 This is the package DAG, @emph{including} implicit inputs.
6473 For instance, the following command:
6476 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6479 ... yields this bigger graph:
6481 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6483 At the bottom of the graph, we see all the implicit inputs of
6484 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6486 Now, note that the dependencies of these implicit inputs---that is, the
6487 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6488 here, for conciseness.
6491 Similar to @code{bag-emerged}, but this time including all the bootstrap
6494 @item bag-with-origins
6495 Similar to @code{bag}, but also showing origins and their dependencies.
6498 This is the most detailed representation: It shows the DAG of
6499 derivations (@pxref{Derivations}) and plain store items. Compared to
6500 the above representation, many additional nodes are visible, including
6501 build scripts, patches, Guile modules, etc.
6503 For this type of graph, it is also possible to pass a @file{.drv} file
6504 name instead of a package name, as in:
6507 guix graph -t derivation `guix system build -d my-config.scm`
6511 All the types above correspond to @emph{build-time dependencies}. The
6512 following graph type represents the @emph{run-time dependencies}:
6516 This is the graph of @dfn{references} of a package output, as returned
6517 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6519 If the given package output is not available in the store, @command{guix
6520 graph} attempts to obtain dependency information from substitutes.
6522 Here you can also pass a store file name instead of a package name. For
6523 example, the command below produces the reference graph of your profile
6524 (which can be big!):
6527 guix graph -t references `readlink -f ~/.guix-profile`
6531 This is the graph of the @dfn{referrers} of a store item, as returned by
6532 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6534 This relies exclusively on local information from your store. For
6535 instance, let us suppose that the current Inkscape is available in 10
6536 profiles on your machine; @command{guix graph -t referrers inkscape}
6537 will show a graph rooted at Inkscape and with those 10 profiles linked
6540 It can help determine what is preventing a store item from being garbage
6545 The available options are the following:
6548 @item --type=@var{type}
6549 @itemx -t @var{type}
6550 Produce a graph output of @var{type}, where @var{type} must be one of
6551 the values listed above.
6554 List the supported graph types.
6556 @item --backend=@var{backend}
6557 @itemx -b @var{backend}
6558 Produce a graph using the selected @var{backend}.
6560 @item --list-backends
6561 List the supported graph backends.
6563 Currently, the available backends are Graphviz and d3.js.
6565 @item --expression=@var{expr}
6566 @itemx -e @var{expr}
6567 Consider the package @var{expr} evaluates to.
6569 This is useful to precisely refer to a package, as in this example:
6572 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6577 @node Invoking guix environment
6578 @section Invoking @command{guix environment}
6580 @cindex reproducible build environments
6581 @cindex development environments
6582 @cindex @command{guix environment}
6583 @cindex environment, package build environment
6584 The purpose of @command{guix environment} is to assist hackers in
6585 creating reproducible development environments without polluting their
6586 package profile. The @command{guix environment} tool takes one or more
6587 packages, builds all of their inputs, and creates a shell
6588 environment to use them.
6590 The general syntax is:
6593 guix environment @var{options} @var{package}@dots{}
6596 The following example spawns a new shell set up for the development of
6600 guix environment guile
6603 If the needed dependencies are not built yet, @command{guix environment}
6604 automatically builds them. The environment of the new shell is an augmented
6605 version of the environment that @command{guix environment} was run in.
6606 It contains the necessary search paths for building the given package
6607 added to the existing environment variables. To create a ``pure''
6608 environment, in which the original environment variables have been unset,
6609 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6610 environment variables such as @code{PATH} in their @file{~/.bashrc}
6611 file. As a consequence, when @code{guix environment} launches it, Bash
6612 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6613 environment variables. It is an error to define such environment
6614 variables in @file{.bashrc}; instead, they should be defined in
6615 @file{.bash_profile}, which is sourced only by log-in shells.
6616 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6617 details on Bash start-up files.}.
6619 @vindex GUIX_ENVIRONMENT
6620 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6621 variable in the shell it spawns; its value is the file name of the
6622 profile of this environment. This allows users to, say, define a
6623 specific prompt for development environments in their @file{.bashrc}
6624 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6627 if [ -n "$GUIX_ENVIRONMENT" ]
6629 export PS1="\u@@\h \w [dev]\$ "
6634 ... or to browse the profile:
6637 $ ls "$GUIX_ENVIRONMENT/bin"
6640 Additionally, more than one package may be specified, in which case the
6641 union of the inputs for the given packages are used. For example, the
6642 command below spawns a shell where all of the dependencies of both Guile
6643 and Emacs are available:
6646 guix environment guile emacs
6649 Sometimes an interactive shell session is not desired. An arbitrary
6650 command may be invoked by placing the @code{--} token to separate the
6651 command from the rest of the arguments:
6654 guix environment guile -- make -j4
6657 In other situations, it is more convenient to specify the list of
6658 packages needed in the environment. For example, the following command
6659 runs @command{python} from an environment containing Python@tie{}2.7 and
6663 guix environment --ad-hoc python2-numpy python-2.7 -- python
6666 Furthermore, one might want the dependencies of a package and also some
6667 additional packages that are not build-time or runtime dependencies, but
6668 are useful when developing nonetheless. Because of this, the
6669 @code{--ad-hoc} flag is positional. Packages appearing before
6670 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6671 added to the environment. Packages appearing after are interpreted as
6672 packages that will be added to the environment directly. For example,
6673 the following command creates a Guix development environment that
6674 additionally includes Git and strace:
6677 guix environment guix --ad-hoc git strace
6680 Sometimes it is desirable to isolate the environment as much as
6681 possible, for maximal purity and reproducibility. In particular, when
6682 using Guix on a host distro that is not GuixSD, it is desirable to
6683 prevent access to @file{/usr/bin} and other system-wide resources from
6684 the development environment. For example, the following command spawns
6685 a Guile REPL in a ``container'' where only the store and the current
6686 working directory are mounted:
6689 guix environment --ad-hoc --container guile -- guile
6693 The @code{--container} option requires Linux-libre 3.19 or newer.
6696 The available options are summarized below.
6699 @item --root=@var{file}
6700 @itemx -r @var{file}
6701 @cindex persistent environment
6702 @cindex garbage collector root, for environments
6703 Make @var{file} a symlink to the profile for this environment, and
6704 register it as a garbage collector root.
6706 This is useful if you want to protect your environment from garbage
6707 collection, to make it ``persistent''.
6709 When this option is omitted, the environment is protected from garbage
6710 collection only for the duration of the @command{guix environment}
6711 session. This means that next time you recreate the same environment,
6712 you could have to rebuild or re-download packages.
6714 @item --expression=@var{expr}
6715 @itemx -e @var{expr}
6716 Create an environment for the package or list of packages that
6717 @var{expr} evaluates to.
6719 For example, running:
6722 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6725 starts a shell with the environment for this specific variant of the
6731 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6734 starts a shell with all the GuixSD base packages available.
6736 The above commands only use the default output of the given packages.
6737 To select other outputs, two element tuples can be specified:
6740 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6743 @item --load=@var{file}
6744 @itemx -l @var{file}
6745 Create an environment for the package or list of packages that the code
6746 within @var{file} evaluates to.
6748 As an example, @var{file} might contain a definition like this
6749 (@pxref{Defining Packages}):
6752 @verbatiminclude environment-gdb.scm
6756 Include all specified packages in the resulting environment, as if an
6757 @i{ad hoc} package were defined with them as inputs. This option is
6758 useful for quickly creating an environment without having to write a
6759 package expression to contain the desired inputs.
6761 For instance, the command:
6764 guix environment --ad-hoc guile guile-sdl -- guile
6767 runs @command{guile} in an environment where Guile and Guile-SDL are
6770 Note that this example implicitly asks for the default output of
6771 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6772 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6773 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6775 This option may be composed with the default behavior of @command{guix
6776 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6777 as packages whose dependencies will be added to the environment, the
6778 default behavior. Packages appearing after are interpreted as packages
6779 that will be added to the environment directly.
6782 Unset existing environment variables when building the new environment.
6783 This has the effect of creating an environment in which search paths
6784 only contain package inputs.
6786 @item --search-paths
6787 Display the environment variable definitions that make up the
6790 @item --system=@var{system}
6791 @itemx -s @var{system}
6792 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6797 Run @var{command} within an isolated container. The current working
6798 directory outside the container is mapped inside the container.
6799 Additionally, a dummy home directory is created that matches the current
6800 user's home directory, and @file{/etc/passwd} is configured accordingly.
6801 The spawned process runs as the current user outside the container, but
6802 has root privileges in the context of the container.
6806 For containers, share the network namespace with the host system.
6807 Containers created without this flag only have access to the loopback
6810 @item --expose=@var{source}[=@var{target}]
6811 For containers, expose the file system @var{source} from the host system
6812 as the read-only file system @var{target} within the container. If
6813 @var{target} is not specified, @var{source} is used as the target mount
6814 point in the container.
6816 The example below spawns a Guile REPL in a container in which the user's
6817 home directory is accessible read-only via the @file{/exchange}
6821 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6824 @item --share=@var{source}[=@var{target}]
6825 For containers, share the file system @var{source} from the host system
6826 as the writable file system @var{target} within the container. If
6827 @var{target} is not specified, @var{source} is used as the target mount
6828 point in the container.
6830 The example below spawns a Guile REPL in a container in which the user's
6831 home directory is accessible for both reading and writing via the
6832 @file{/exchange} directory:
6835 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6839 @command{guix environment}
6840 also supports all of the common build options that @command{guix
6841 build} supports (@pxref{Common Build Options}).
6844 @node Invoking guix publish
6845 @section Invoking @command{guix publish}
6847 @cindex @command{guix publish}
6848 The purpose of @command{guix publish} is to enable users to easily share
6849 their store with others, who can then use it as a substitute server
6850 (@pxref{Substitutes}).
6852 When @command{guix publish} runs, it spawns an HTTP server which allows
6853 anyone with network access to obtain substitutes from it. This means
6854 that any machine running Guix can also act as if it were a build farm,
6855 since the HTTP interface is compatible with Hydra, the software behind
6856 the @code{hydra.gnu.org} build farm.
6858 For security, each substitute is signed, allowing recipients to check
6859 their authenticity and integrity (@pxref{Substitutes}). Because
6860 @command{guix publish} uses the signing key of the system, which is only
6861 readable by the system administrator, it must be started as root; the
6862 @code{--user} option makes it drop root privileges early on.
6864 The signing key pair must be generated before @command{guix publish} is
6865 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6868 The general syntax is:
6871 guix publish @var{options}@dots{}
6874 Running @command{guix publish} without any additional arguments will
6875 spawn an HTTP server on port 8080:
6881 Once a publishing server has been authorized (@pxref{Invoking guix
6882 archive}), the daemon may download substitutes from it:
6885 guix-daemon --substitute-urls=http://example.org:8080
6888 By default, @command{guix publish} compresses archives on the fly as it
6889 serves them. This ``on-the-fly'' mode is convenient in that it requires
6890 no setup and is immediately available. However, when serving lots of
6891 clients, we recommend using the @option{--cache} option, which enables
6892 caching of the archives before they are sent to clients---see below for
6893 details. The @command{guix weather} command provides a handy way to
6894 check what a server provides (@pxref{Invoking guix weather}).
6896 As a bonus, @command{guix publish} also serves as a content-addressed
6897 mirror for source files referenced in @code{origin} records
6898 (@pxref{origin Reference}). For instance, assuming @command{guix
6899 publish} is running on @code{example.org}, the following URL returns the
6900 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6901 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6904 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6907 Obviously, these URLs only work for files that are in the store; in
6908 other cases, they return 404 (``Not Found'').
6910 The following options are available:
6913 @item --port=@var{port}
6914 @itemx -p @var{port}
6915 Listen for HTTP requests on @var{port}.
6917 @item --listen=@var{host}
6918 Listen on the network interface for @var{host}. The default is to
6919 accept connections from any interface.
6921 @item --user=@var{user}
6922 @itemx -u @var{user}
6923 Change privileges to @var{user} as soon as possible---i.e., once the
6924 server socket is open and the signing key has been read.
6926 @item --compression[=@var{level}]
6927 @itemx -C [@var{level}]
6928 Compress data using the given @var{level}. When @var{level} is zero,
6929 disable compression. The range 1 to 9 corresponds to different gzip
6930 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6933 Unless @option{--cache} is used, compression occurs on the fly and
6934 the compressed streams are not
6935 cached. Thus, to reduce load on the machine that runs @command{guix
6936 publish}, it may be a good idea to choose a low compression level, to
6937 run @command{guix publish} behind a caching proxy, or to use
6938 @option{--cache}. Using @option{--cache} has the advantage that it
6939 allows @command{guix publish} to add @code{Content-Length} HTTP header
6942 @item --cache=@var{directory}
6943 @itemx -c @var{directory}
6944 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6945 and only serve archives that are in cache.
6947 When this option is omitted, archives and meta-data are created
6948 on-the-fly. This can reduce the available bandwidth, especially when
6949 compression is enabled, since this may become CPU-bound. Another
6950 drawback of the default mode is that the length of archives is not known
6951 in advance, so @command{guix publish} does not add a
6952 @code{Content-Length} HTTP header to its responses, which in turn
6953 prevents clients from knowing the amount of data being downloaded.
6955 Conversely, when @option{--cache} is used, the first request for a store
6956 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6957 background process to @dfn{bake} the archive---computing its
6958 @code{.narinfo} and compressing the archive, if needed. Once the
6959 archive is cached in @var{directory}, subsequent requests succeed and
6960 are served directly from the cache, which guarantees that clients get
6961 the best possible bandwidth.
6963 The ``baking'' process is performed by worker threads. By default, one
6964 thread per CPU core is created, but this can be customized. See
6965 @option{--workers} below.
6967 When @option{--ttl} is used, cached entries are automatically deleted
6968 when they have expired.
6970 @item --workers=@var{N}
6971 When @option{--cache} is used, request the allocation of @var{N} worker
6972 threads to ``bake'' archives.
6974 @item --ttl=@var{ttl}
6975 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6976 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6977 days, @code{1m} means 1 month, and so on.
6979 This allows the user's Guix to keep substitute information in cache for
6980 @var{ttl}. However, note that @code{guix publish} does not itself
6981 guarantee that the store items it provides will indeed remain available
6982 for as long as @var{ttl}.
6984 Additionally, when @option{--cache} is used, cached entries that have
6985 not been accessed for @var{ttl} and that no longer have a corresponding
6986 item in the store, may be deleted.
6988 @item --nar-path=@var{path}
6989 Use @var{path} as the prefix for the URLs of ``nar'' files
6990 (@pxref{Invoking guix archive, normalized archives}).
6992 By default, nars are served at a URL such as
6993 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6994 change the @code{/nar} part to @var{path}.
6996 @item --public-key=@var{file}
6997 @itemx --private-key=@var{file}
6998 Use the specific @var{file}s as the public/private key pair used to sign
6999 the store items being published.
7001 The files must correspond to the same key pair (the private key is used
7002 for signing and the public key is merely advertised in the signature
7003 metadata). They must contain keys in the canonical s-expression format
7004 as produced by @command{guix archive --generate-key} (@pxref{Invoking
7005 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
7006 @file{/etc/guix/signing-key.sec} are used.
7008 @item --repl[=@var{port}]
7009 @itemx -r [@var{port}]
7010 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
7011 Reference Manual}) on @var{port} (37146 by default). This is used
7012 primarily for debugging a running @command{guix publish} server.
7015 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
7016 instantiate a @code{guix-publish-service-type} service in the @code{services} field
7017 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
7018 @code{guix-publish-service-type}}).
7020 If you are instead running Guix on a ``foreign distro'', follow these
7025 If your host distro uses the systemd init system:
7028 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
7029 /etc/systemd/system/
7030 # systemctl start guix-publish && systemctl enable guix-publish
7034 If your host distro uses the Upstart init system:
7037 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
7038 # start guix-publish
7042 Otherwise, proceed similarly with your distro's init system.
7045 @node Invoking guix challenge
7046 @section Invoking @command{guix challenge}
7048 @cindex reproducible builds
7049 @cindex verifiable builds
7050 @cindex @command{guix challenge}
7052 Do the binaries provided by this server really correspond to the source
7053 code it claims to build? Is a package build process deterministic?
7054 These are the questions the @command{guix challenge} command attempts to
7057 The former is obviously an important question: Before using a substitute
7058 server (@pxref{Substitutes}), one had better @emph{verify} that it
7059 provides the right binaries, and thus @emph{challenge} it. The latter
7060 is what enables the former: If package builds are deterministic, then
7061 independent builds of the package should yield the exact same result,
7062 bit for bit; if a server provides a binary different from the one
7063 obtained locally, it may be either corrupt or malicious.
7065 We know that the hash that shows up in @file{/gnu/store} file names is
7066 the hash of all the inputs of the process that built the file or
7067 directory---compilers, libraries, build scripts,
7068 etc. (@pxref{Introduction}). Assuming deterministic build processes,
7069 one store file name should map to exactly one build output.
7070 @command{guix challenge} checks whether there is, indeed, a single
7071 mapping by comparing the build outputs of several independent builds of
7072 any given store item.
7074 The command output looks like this:
7077 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
7078 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
7079 updating list of substitutes from 'https://guix.example.org'... 100.0%
7080 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
7081 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
7082 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
7083 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
7084 /gnu/store/@dots{}-git-2.5.0 contents differ:
7085 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
7086 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
7087 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
7088 /gnu/store/@dots{}-pius-2.1.1 contents differ:
7089 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
7090 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
7091 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
7095 In this example, @command{guix challenge} first scans the store to
7096 determine the set of locally-built derivations---as opposed to store
7097 items that were downloaded from a substitute server---and then queries
7098 all the substitute servers. It then reports those store items for which
7099 the servers obtained a result different from the local build.
7101 @cindex non-determinism, in package builds
7102 As an example, @code{guix.example.org} always gets a different answer.
7103 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
7104 case of Git. This might indicate that the build process of Git is
7105 non-deterministic, meaning that its output varies as a function of
7106 various things that Guix does not fully control, in spite of building
7107 packages in isolated environments (@pxref{Features}). Most common
7108 sources of non-determinism include the addition of timestamps in build
7109 results, the inclusion of random numbers, and directory listings sorted
7110 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
7113 To find out what is wrong with this Git binary, we can do something along
7114 these lines (@pxref{Invoking guix archive}):
7117 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
7118 | guix archive -x /tmp/git
7119 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
7122 This command shows the difference between the files resulting from the
7123 local build, and the files resulting from the build on
7124 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
7125 diffutils, Comparing and Merging Files}). The @command{diff} command
7126 works great for text files. When binary files differ, a better option
7127 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
7128 visualize differences for all kinds of files.
7130 Once you have done that work, you can tell whether the differences are due
7131 to a non-deterministic build process or to a malicious server. We try
7132 hard to remove sources of non-determinism in packages to make it easier
7133 to verify substitutes, but of course, this is a process that
7134 involves not just Guix, but a large part of the free software community.
7135 In the meantime, @command{guix challenge} is one tool to help address
7138 If you are writing packages for Guix, you are encouraged to check
7139 whether @code{hydra.gnu.org} and other substitute servers obtain the
7140 same build result as you did with:
7143 $ guix challenge @var{package}
7147 where @var{package} is a package specification such as
7148 @code{guile@@2.0} or @code{glibc:debug}.
7150 The general syntax is:
7153 guix challenge @var{options} [@var{packages}@dots{}]
7156 When a difference is found between the hash of a locally-built item and
7157 that of a server-provided substitute, or among substitutes provided by
7158 different servers, the command displays it as in the example above and
7159 its exit code is 2 (other non-zero exit codes denote other kinds of
7162 The one option that matters is:
7166 @item --substitute-urls=@var{urls}
7167 Consider @var{urls} the whitespace-separated list of substitute source
7172 Show details about matches (identical contents) in addition to
7173 information about mismatches.
7177 @node Invoking guix copy
7178 @section Invoking @command{guix copy}
7180 @cindex copy, of store items, over SSH
7181 @cindex SSH, copy of store items
7182 @cindex sharing store items across machines
7183 @cindex transferring store items across machines
7184 The @command{guix copy} command copies items from the store of one
7185 machine to that of another machine over a secure shell (SSH)
7186 connection@footnote{This command is available only when Guile-SSH was
7187 found. @xref{Requirements}, for details.}. For example, the following
7188 command copies the @code{coreutils} package, the user's profile, and all
7189 their dependencies over to @var{host}, logged in as @var{user}:
7192 guix copy --to=@var{user}@@@var{host} \
7193 coreutils `readlink -f ~/.guix-profile`
7196 If some of the items to be copied are already present on @var{host},
7197 they are not actually sent.
7199 The command below retrieves @code{libreoffice} and @code{gimp} from
7200 @var{host}, assuming they are available there:
7203 guix copy --from=@var{host} libreoffice gimp
7206 The SSH connection is established using the Guile-SSH client, which is
7207 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
7208 @file{~/.ssh/config}, and uses the SSH agent for authentication.
7210 The key used to sign items that are sent must be accepted by the remote
7211 machine. Likewise, the key used by the remote machine to sign items you
7212 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
7213 own daemon. @xref{Invoking guix archive}, for more information about
7214 store item authentication.
7216 The general syntax is:
7219 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
7222 You must always specify one of the following options:
7225 @item --to=@var{spec}
7226 @itemx --from=@var{spec}
7227 Specify the host to send to or receive from. @var{spec} must be an SSH
7228 spec such as @code{example.org}, @code{charlie@@example.org}, or
7229 @code{charlie@@example.org:2222}.
7232 The @var{items} can be either package names, such as @code{gimp}, or
7233 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
7235 When specifying the name of a package to send, it is first built if
7236 needed, unless @option{--dry-run} was specified. Common build options
7237 are supported (@pxref{Common Build Options}).
7240 @node Invoking guix container
7241 @section Invoking @command{guix container}
7243 @cindex @command{guix container}
7245 As of version @value{VERSION}, this tool is experimental. The interface
7246 is subject to radical change in the future.
7249 The purpose of @command{guix container} is to manipulate processes
7250 running within an isolated environment, commonly known as a
7251 ``container'', typically created by the @command{guix environment}
7252 (@pxref{Invoking guix environment}) and @command{guix system container}
7253 (@pxref{Invoking guix system}) commands.
7255 The general syntax is:
7258 guix container @var{action} @var{options}@dots{}
7261 @var{action} specifies the operation to perform with a container, and
7262 @var{options} specifies the context-specific arguments for the action.
7264 The following actions are available:
7268 Execute a command within the context of a running container.
7273 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
7276 @var{pid} specifies the process ID of the running container.
7277 @var{program} specifies an executable file name within the root file
7278 system of the container. @var{arguments} are the additional options that
7279 will be passed to @var{program}.
7281 The following command launches an interactive login shell inside a
7282 GuixSD container, started by @command{guix system container}, and whose
7286 guix container exec 9001 /run/current-system/profile/bin/bash --login
7289 Note that the @var{pid} cannot be the parent process of a container. It
7290 must be PID 1 of the container or one of its child processes.
7294 @node Invoking guix weather
7295 @section Invoking @command{guix weather}
7297 Occasionally you're grumpy because substitutes are lacking and you end
7298 up building packages by yourself (@pxref{Substitutes}). The
7299 @command{guix weather} command reports on substitute availability on the
7300 specified servers so you can have an idea of whether you'll be grumpy
7301 today. It can sometimes be useful info as a user, but it is primarily
7302 useful to people running @command{guix publish} (@pxref{Invoking guix
7305 @cindex statistics, for substitutes
7306 @cindex availability of substitutes
7307 @cindex substitute availability
7308 @cindex weather, substitute availability
7309 Here's a sample run:
7312 $ guix weather --substitute-urls=https://guix.example.org
7313 computing 5,872 package derivations for x86_64-linux...
7314 looking for 6,128 store items on https://guix.example.org..
7315 updating list of substitutes from 'https://guix.example.org'... 100.0%
7316 https://guix.example.org
7317 43.4% substitutes available (2,658 out of 6,128)
7318 7,032.5 MiB of nars (compressed)
7319 19,824.2 MiB on disk (uncompressed)
7320 0.030 seconds per request (182.9 seconds in total)
7321 33.5 requests per second
7324 As you can see, it reports the fraction of all the packages for which
7325 substitutes are available on the server---regardless of whether
7326 substitutes are enabled, and regardless of whether this server's signing
7327 key is authorized. It also reports the size of the compressed archives
7328 (``nars'') provided by the server, the size the corresponding store
7329 items occupy in the store (assuming deduplication is turned off), and
7330 the server's throughput.
7332 To achieve that, @command{guix weather} queries over HTTP(S) meta-data
7333 (@dfn{narinfos}) for all the relevant store items. Like @command{guix
7334 challenge}, it ignores signatures on those substitutes, which is
7335 innocuous since the command only gathers statistics and cannot install
7338 Among other things, it is possible to query specific system types and
7339 specific package sets. The available options are listed below.
7342 @item --substitute-urls=@var{urls}
7343 @var{urls} is the space-separated list of substitute server URLs to
7344 query. When this option is omitted, the default set of substitute
7347 @item --system=@var{system}
7348 @itemx -s @var{system}
7349 Query substitutes for @var{system}---e.g., @code{aarch64-linux}. This
7350 option can be repeated, in which case @command{guix weather} will query
7351 substitutes for several system types.
7353 @item --manifest=@var{file}
7354 Instead of querying substitutes for all the packages, only ask for those
7355 specified in @var{file}. @var{file} must contain a @dfn{manifest}, as
7356 with the @code{-m} option of @command{guix package} (@pxref{Invoking
7361 @c *********************************************************************
7362 @node GNU Distribution
7363 @chapter GNU Distribution
7365 @cindex Guix System Distribution
7367 Guix comes with a distribution of the GNU system consisting entirely of
7368 free software@footnote{The term ``free'' here refers to the
7369 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
7370 users of that software}.}. The
7371 distribution can be installed on its own (@pxref{System Installation}),
7372 but it is also possible to install Guix as a package manager on top of
7373 an installed GNU/Linux system (@pxref{Installation}). To distinguish
7374 between the two, we refer to the standalone distribution as the Guix
7375 System Distribution, or GuixSD.
7377 The distribution provides core GNU packages such as GNU libc, GCC, and
7378 Binutils, as well as many GNU and non-GNU applications. The complete
7379 list of available packages can be browsed
7380 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7381 running @command{guix package} (@pxref{Invoking guix package}):
7384 guix package --list-available
7387 Our goal is to provide a practical 100% free software distribution of
7388 Linux-based and other variants of GNU, with a focus on the promotion and
7389 tight integration of GNU components, and an emphasis on programs and
7390 tools that help users exert that freedom.
7392 Packages are currently available on the following platforms:
7397 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7400 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7403 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7404 using the EABI hard-float application binary interface (ABI),
7405 and Linux-Libre kernel.
7408 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7409 currently in an experimental stage, with limited support.
7410 @xref{Contributing}, for how to help!
7412 @item mips64el-linux
7413 little-endian 64-bit MIPS processors, specifically the Loongson series,
7414 n32 ABI, and Linux-Libre kernel.
7418 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7421 For information on porting to other architectures or kernels,
7425 * System Installation:: Installing the whole operating system.
7426 * System Configuration:: Configuring the operating system.
7427 * Documentation:: Browsing software user manuals.
7428 * Installing Debugging Files:: Feeding the debugger.
7429 * Security Updates:: Deploying security fixes quickly.
7430 * Package Modules:: Packages from the programmer's viewpoint.
7431 * Packaging Guidelines:: Growing the distribution.
7432 * Bootstrapping:: GNU/Linux built from scratch.
7433 * Porting:: Targeting another platform or kernel.
7436 Building this distribution is a cooperative effort, and you are invited
7437 to join! @xref{Contributing}, for information about how you can help.
7439 @node System Installation
7440 @section System Installation
7442 @cindex installing GuixSD
7443 @cindex Guix System Distribution
7444 This section explains how to install the Guix System Distribution (GuixSD)
7445 on a machine. The Guix package manager can
7446 also be installed on top of a running GNU/Linux system,
7447 @pxref{Installation}.
7451 @c This paragraph is for people reading this from tty2 of the
7452 @c installation image.
7453 You are reading this documentation with an Info reader. For details on
7454 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7455 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7456 Info}. Hit @kbd{l} afterwards to come back here.
7458 Alternately, run @command{info info} in another tty to keep the manual
7464 * Limitations:: What you can expect.
7465 * Hardware Considerations:: Supported hardware.
7466 * USB Stick Installation:: Preparing the installation medium.
7467 * Preparing for Installation:: Networking, partitioning, etc.
7468 * Proceeding with the Installation:: The real thing.
7469 * Installing GuixSD in a VM:: GuixSD playground.
7470 * Building the Installation Image:: How this comes to be.
7474 @subsection Limitations
7476 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7477 not production-ready. It may contain bugs and lack important
7478 features. Thus, if you are looking for a stable production system that
7479 respects your freedom as a computer user, a good solution at this point
7480 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7481 the more established GNU/Linux distributions}. We hope you can soon switch
7482 to the GuixSD without fear, of course. In the meantime, you can
7483 also keep using your distribution and try out the package manager on top
7484 of it (@pxref{Installation}).
7486 Before you proceed with the installation, be aware of the following
7487 noteworthy limitations applicable to version @value{VERSION}:
7491 The installation process does not include a graphical user interface and
7492 requires familiarity with GNU/Linux (see the following subsections to
7493 get a feel of what that means.)
7496 Support for the Logical Volume Manager (LVM) is missing.
7499 More and more system services are provided (@pxref{Services}), but some
7503 More than 5,300 packages are available, but you may
7504 occasionally find that a useful package is missing.
7507 GNOME, Xfce, LXDE, and Enlightenment are available (@pxref{Desktop Services}),
7508 as well as a number of X11 window managers. However, some graphical
7509 applications may be missing, as well as KDE.
7512 You have been warned! But more than a disclaimer, this is an invitation
7513 to report issues (and success stories!), and to join us in improving it.
7514 @xref{Contributing}, for more info.
7517 @node Hardware Considerations
7518 @subsection Hardware Considerations
7520 @cindex hardware support on GuixSD
7521 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7522 builds around the kernel Linux-libre, which means that only hardware for
7523 which free software drivers and firmware exist is supported. Nowadays,
7524 a wide range of off-the-shelf hardware is supported on
7525 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7526 Ethernet controllers. Unfortunately, there are still areas where
7527 hardware vendors deny users control over their own computing, and such
7528 hardware is not supported on GuixSD.
7530 @cindex WiFi, hardware support
7531 One of the main areas where free drivers or firmware are lacking is WiFi
7532 devices. WiFi devices known to work include those using Atheros chips
7533 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7534 driver, and those using Broadcom/AirForce chips (BCM43xx with
7535 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7536 Linux-libre driver. Free firmware exists for both and is available
7537 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7538 (@pxref{operating-system Reference, @code{firmware}}).
7540 @cindex RYF, Respects Your Freedom
7541 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7542 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7543 certification program for hardware products that respect your freedom
7544 and your privacy and ensure that you have control over your device. We
7545 encourage you to check the list of RYF-certified devices.
7547 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7548 web site. It contains a catalog of hardware devices with information
7549 about their support in GNU/Linux.
7552 @node USB Stick Installation
7553 @subsection USB Stick Installation
7555 An installation image for USB sticks can be downloaded from
7556 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
7557 where @var{system} is one of:
7561 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7564 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7567 @c start duplication of authentication part from ``Binary Installation''
7568 Make sure to download the associated @file{.sig} file and to verify the
7569 authenticity of the image against it, along these lines:
7572 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7573 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7576 If that command fails because you do not have the required public key,
7577 then run this command to import it:
7580 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7584 and rerun the @code{gpg --verify} command.
7587 This image contains a single partition with the tools necessary for an
7588 installation. It is meant to be copied @emph{as is} to a large-enough
7591 To copy the image to a USB stick, follow these steps:
7595 Decompress the image using the @command{xz} command:
7598 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
7602 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7603 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7604 copy the image with:
7607 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
7611 Access to @file{/dev/sdX} usually requires root privileges.
7614 Once this is done, you should be able to reboot the system and boot from
7615 the USB stick. The latter usually requires you to get in the BIOS or
7616 UEFI boot menu, where you can choose to boot from the USB stick.
7618 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7619 GuixSD in a virtual machine (VM).
7621 @node Preparing for Installation
7622 @subsection Preparing for Installation
7624 Once you have successfully booted the image on the USB stick, you should
7625 end up with a root prompt. Several console TTYs are configured and can
7626 be used to run commands as root. TTY2 shows this documentation,
7627 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7628 Stand-alone GNU Info}). The installation system runs the GPM mouse
7629 daemon, which allows you to select text with the left mouse button and
7630 to paste it with the middle button.
7633 Installation requires access to the Internet so that any missing
7634 dependencies of your system configuration can be downloaded. See the
7635 ``Networking'' section below.
7638 The installation system includes many common tools needed for this task.
7639 But it is also a full-blown GuixSD system, which means that you can
7640 install additional packages, should you need it, using @command{guix
7641 package} (@pxref{Invoking guix package}).
7643 @subsubsection Keyboard Layout
7645 @cindex keyboard layout
7646 The installation image uses the US qwerty keyboard layout. If you want
7647 to change it, you can use the @command{loadkeys} command. For example,
7648 the following command selects the Dvorak keyboard layout:
7654 See the files under @file{/run/current-system/profile/share/keymaps} for
7655 a list of available keyboard layouts. Run @command{man loadkeys} for
7658 @subsubsection Networking
7660 Run the following command see what your network interfaces are called:
7667 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7673 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7674 Wired interfaces have a name starting with @samp{e}; for example, the
7675 interface corresponding to the first on-board Ethernet controller is
7676 called @samp{eno1}. Wireless interfaces have a name starting with
7677 @samp{w}, like @samp{w1p2s0}.
7680 @item Wired connection
7681 To configure a wired network run the following command, substituting
7682 @var{interface} with the name of the wired interface you want to use.
7685 ifconfig @var{interface} up
7688 @item Wireless connection
7691 To configure wireless networking, you can create a configuration file
7692 for the @command{wpa_supplicant} configuration tool (its location is not
7693 important) using one of the available text editors such as
7697 zile wpa_supplicant.conf
7700 As an example, the following stanza can go to this file and will work
7701 for many wireless networks, provided you give the actual SSID and
7702 passphrase for the network you are connecting to:
7706 ssid="@var{my-ssid}"
7708 psk="the network's secret passphrase"
7712 Start the wireless service and run it in the background with the
7713 following command (substitute @var{interface} with the name of the
7714 network interface you want to use):
7717 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7720 Run @command{man wpa_supplicant} for more information.
7724 At this point, you need to acquire an IP address. On a network where IP
7725 addresses are automatically assigned @i{via} DHCP, you can run:
7728 dhclient -v @var{interface}
7731 Try to ping a server to see if networking is up and running:
7737 Setting up network access is almost always a requirement because the
7738 image does not contain all the software and tools that may be needed.
7740 @cindex installing over SSH
7741 If you want to, you can continue the installation remotely by starting
7745 herd start ssh-daemon
7748 Make sure to either set a password with @command{passwd}, or configure
7749 OpenSSH public key authentication before logging in.
7751 @subsubsection Disk Partitioning
7753 Unless this has already been done, the next step is to partition, and
7754 then format the target partition(s).
7756 The installation image includes several partitioning tools, including
7757 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7758 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7759 the partition layout you want:
7765 If your disk uses the GUID Partition Table (GPT) format and you plan to
7766 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7767 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7770 @cindex EFI, installation
7771 @cindex UEFI, installation
7772 @cindex ESP, EFI system partition
7773 If you instead wish to use EFI-based GRUB, a FAT32 @dfn{EFI System Partition}
7774 (ESP) is required. This partition should be mounted at @file{/boot/efi} and
7775 must have the @code{esp} flag set. E.g., for @command{parted}:
7778 parted /dev/sda set 1 esp on
7781 Once you are done partitioning the target hard disk drive, you have to
7782 create a file system on the relevant partition(s)@footnote{Currently
7783 GuixSD only supports ext4 and btrfs file systems. In particular, code
7784 that reads partition UUIDs and labels only works for these file system
7787 Preferably, assign partitions a label so that you can easily and
7788 reliably refer to them in @code{file-system} declarations (@pxref{File
7789 Systems}). This is typically done using the @code{-L} option of
7790 @command{mkfs.ext4} and related commands. So, assuming the target root
7791 partition lives at @file{/dev/sda1}, a file system with the label
7792 @code{my-root} can be created with:
7795 mkfs.ext4 -L my-root /dev/sda1
7798 @cindex encrypted disk
7799 If you are instead planning to encrypt the root partition, you can use
7800 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7801 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7802 @code{man cryptsetup}} for more information.) Assuming you want to
7803 store the root partition on @file{/dev/sda1}, the command sequence would
7804 be along these lines:
7807 cryptsetup luksFormat /dev/sda1
7808 cryptsetup open --type luks /dev/sda1 my-partition
7809 mkfs.ext4 -L my-root /dev/mapper/my-partition
7812 Once that is done, mount the target root partition under @file{/mnt}
7813 with a command like (again, assuming @code{my-root} is the label of the
7817 mount LABEL=my-root /mnt
7820 Also mount any other partitions you would like to use on the target
7821 system relative to this path. If you have @file{/boot} on a separate
7822 partition for example, mount it at @file{/mnt/boot} now so it is found
7823 by @code{guix system init} afterwards.
7825 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7826 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7827 sure to initialize them with @command{mkswap}. Assuming you have one
7828 swap partition on @file{/dev/sda2}, you would run:
7835 Alternatively, you may use a swap file. For example, assuming that in
7836 the new system you want to use the file @file{/swapfile} as a swap file,
7837 you would run@footnote{This example will work for many types of file
7838 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7839 btrfs), the required steps may be different. For details, see the
7840 manual pages for @command{mkswap} and @command{swapon}.}:
7843 # This is 10 GiB of swap space. Adjust "count" to change the size.
7844 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7845 # For security, make the file readable and writable only by root.
7846 chmod 600 /mnt/swapfile
7847 mkswap /mnt/swapfile
7848 swapon /mnt/swapfile
7851 Note that if you have encrypted the root partition and created a swap
7852 file in its file system as described above, then the encryption also
7853 protects the swap file, just like any other file in that file system.
7855 @node Proceeding with the Installation
7856 @subsection Proceeding with the Installation
7858 With the target partitions ready and the target root mounted on
7859 @file{/mnt}, we're ready to go. First, run:
7862 herd start cow-store /mnt
7865 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7866 during the installation phase are written to the target disk on @file{/mnt}
7867 rather than kept in memory. This is necessary because the first phase of
7868 the @command{guix system init} command (see below) entails downloads or
7869 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7871 Next, you have to edit a file and
7872 provide the declaration of the operating system to be installed. To
7873 that end, the installation system comes with three text editors: GNU nano
7874 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7875 nvi (a clone of the original BSD @command{vi} editor).
7876 We strongly recommend storing that file on the target root file system, say,
7877 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7878 configuration file once you have rebooted into the newly-installed system.
7880 @xref{Using the Configuration System}, for an overview of the
7881 configuration file. The example configurations discussed in that
7882 section are available under @file{/etc/configuration} in the
7883 installation image. Thus, to get started with a system configuration
7884 providing a graphical display server (a ``desktop'' system), you can run
7885 something along these lines:
7889 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7890 # zile /mnt/etc/config.scm
7893 You should pay attention to what your configuration file contains, and
7898 Make sure the @code{grub-configuration} form refers to the device you
7899 want to install GRUB on. You also need to specify the @code{grub-efi}
7900 package if you wish to use native UEFI boot.
7903 Be sure that your partition labels match the value of their respective
7904 @code{device} fields in your @code{file-system} configuration, assuming
7905 your @code{file-system} configuration sets the value of @code{title} to
7909 If there are encrypted or RAID partitions, make sure to add a
7910 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7913 Once you are done preparing the configuration file, the new system must
7914 be initialized (remember that the target root file system is mounted
7918 guix system init /mnt/etc/config.scm /mnt
7922 This copies all the necessary files and installs GRUB on
7923 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7924 more information, @pxref{Invoking guix system}. This command may trigger
7925 downloads or builds of missing packages, which can take some time.
7927 Once that command has completed---and hopefully succeeded!---you can run
7928 @command{reboot} and boot into the new system. The @code{root} password
7929 in the new system is initially empty; other users' passwords need to be
7930 initialized by running the @command{passwd} command as @code{root},
7931 unless your configuration specifies otherwise
7932 (@pxref{user-account-password, user account passwords}).
7934 @cindex upgrading GuixSD
7935 From then on, you can update GuixSD whenever you want by running
7936 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7937 then running @command{guix system reconfigure} to build a new system
7938 generation with the latest packages and services (@pxref{Invoking guix
7939 system}). We recommend doing that regularly so that your system
7940 includes the latest security updates (@pxref{Security Updates}).
7942 Join us on @code{#guix} on the Freenode IRC network or on
7943 @file{guix-devel@@gnu.org} to share your experience---good or not so
7946 @node Installing GuixSD in a VM
7947 @subsection Installing GuixSD in a Virtual Machine
7949 @cindex virtual machine, GuixSD installation
7950 @cindex virtual private server (VPS)
7951 @cindex VPS (virtual private server)
7952 If you'd like to install GuixSD in a virtual machine (VM) or on a
7953 virtual private server (VPS) rather than on your beloved machine, this
7956 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7957 disk image, follow these steps:
7961 First, retrieve and decompress the GuixSD installation image as
7962 described previously (@pxref{USB Stick Installation}).
7965 Create a disk image that will hold the installed system. To make a
7966 qcow2-formatted disk image, use the @command{qemu-img} command:
7969 qemu-img create -f qcow2 guixsd.img 50G
7972 The resulting file will be much smaller than 50 GB (typically less than
7973 1 MB), but it will grow as the virtualized storage device is filled up.
7976 Boot the USB installation image in an VM:
7979 qemu-system-x86_64 -m 1024 -smp 1 \
7980 -net user -net nic,model=virtio -boot menu=on \
7981 -drive file=guixsd-usb-install-@value{VERSION}.@var{system} \
7982 -drive file=guixsd.img
7985 The ordering of the drives matters.
7987 In the VM console, quickly press the @kbd{F12} key to enter the boot
7988 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7992 You're now root in the VM, proceed with the installation process.
7993 @xref{Preparing for Installation}, and follow the instructions.
7996 Once installation is complete, you can boot the system that's on your
7997 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
8000 @node Building the Installation Image
8001 @subsection Building the Installation Image
8003 @cindex installation image
8004 The installation image described above was built using the @command{guix
8005 system} command, specifically:
8008 guix system disk-image gnu/system/install.scm
8011 Have a look at @file{gnu/system/install.scm} in the source tree,
8012 and see also @ref{Invoking guix system} for more information
8013 about the installation image.
8015 @node System Configuration
8016 @section System Configuration
8018 @cindex system configuration
8019 The Guix System Distribution supports a consistent whole-system configuration
8020 mechanism. By that we mean that all aspects of the global system
8021 configuration---such as the available system services, timezone and
8022 locale settings, user accounts---are declared in a single place. Such
8023 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
8025 One of the advantages of putting all the system configuration under the
8026 control of Guix is that it supports transactional system upgrades, and
8027 makes it possible to roll back to a previous system instantiation,
8028 should something go wrong with the new one (@pxref{Features}). Another
8029 advantage is that it makes it easy to replicate the exact same configuration
8030 across different machines, or at different points in time, without
8031 having to resort to additional administration tools layered on top of
8032 the own tools of the system.
8033 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
8035 This section describes this mechanism. First we focus on the system
8036 administrator's viewpoint---explaining how the system is configured and
8037 instantiated. Then we show how this mechanism can be extended, for
8038 instance to support new system services.
8041 * Using the Configuration System:: Customizing your GNU system.
8042 * operating-system Reference:: Detail of operating-system declarations.
8043 * File Systems:: Configuring file system mounts.
8044 * Mapped Devices:: Block device extra processing.
8045 * User Accounts:: Specifying user accounts.
8046 * Locales:: Language and cultural convention settings.
8047 * Services:: Specifying system services.
8048 * Setuid Programs:: Programs running with root privileges.
8049 * X.509 Certificates:: Authenticating HTTPS servers.
8050 * Name Service Switch:: Configuring libc's name service switch.
8051 * Initial RAM Disk:: Linux-Libre bootstrapping.
8052 * Bootloader Configuration:: Configuring the boot loader.
8053 * Invoking guix system:: Instantiating a system configuration.
8054 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
8055 * Defining Services:: Adding new service definitions.
8058 @node Using the Configuration System
8059 @subsection Using the Configuration System
8061 The operating system is configured by providing an
8062 @code{operating-system} declaration in a file that can then be passed to
8063 the @command{guix system} command (@pxref{Invoking guix system}). A
8064 simple setup, with the default system services, the default Linux-Libre
8065 kernel, initial RAM disk, and boot loader looks like this:
8067 @findex operating-system
8069 @include os-config-bare-bones.texi
8072 This example should be self-describing. Some of the fields defined
8073 above, such as @code{host-name} and @code{bootloader}, are mandatory.
8074 Others, such as @code{packages} and @code{services}, can be omitted, in
8075 which case they get a default value.
8077 Below we discuss the effect of some of the most important fields
8078 (@pxref{operating-system Reference}, for details about all the available
8079 fields), and how to @dfn{instantiate} the operating system using
8080 @command{guix system}.
8082 @unnumberedsubsubsec Globally-Visible Packages
8084 @vindex %base-packages
8085 The @code{packages} field lists packages that will be globally visible
8086 on the system, for all user accounts---i.e., in every user's @code{PATH}
8087 environment variable---in addition to the per-user profiles
8088 (@pxref{Invoking guix package}). The @var{%base-packages} variable
8089 provides all the tools one would expect for basic user and administrator
8090 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
8091 the GNU Zile lightweight text editor, @command{find}, @command{grep},
8092 etc. The example above adds tcpdump to those, taken from the @code{(gnu
8093 packages admin)} module (@pxref{Package Modules}). The
8094 @code{(list package output)} syntax can be used to add a specific output
8098 (use-modules (gnu packages))
8099 (use-modules (gnu packages dns))
8103 (packages (cons (list bind "utils")
8107 @findex specification->package
8108 Referring to packages by variable name, like @var{tcpdump} above, has
8109 the advantage of being unambiguous; it also allows typos and such to be
8110 diagnosed right away as ``unbound variables''. The downside is that one
8111 needs to know which module defines which package, and to augment the
8112 @code{use-package-modules} line accordingly. To avoid that, one can use
8113 the @code{specification->package} procedure of the @code{(gnu packages)}
8114 module, which returns the best package for a given name or name and
8118 (use-modules (gnu packages))
8122 (packages (append (map specification->package
8123 '("tcpdump" "htop" "gnupg@@2.0"))
8127 @unnumberedsubsubsec System Services
8130 @vindex %base-services
8131 The @code{services} field lists @dfn{system services} to be made
8132 available when the system starts (@pxref{Services}).
8133 The @code{operating-system} declaration above specifies that, in
8134 addition to the basic services, we want the @command{lshd} secure shell
8135 daemon listening on port 2222 (@pxref{Networking Services,
8136 @code{lsh-service}}). Under the hood,
8137 @code{lsh-service} arranges so that @code{lshd} is started with the
8138 right command-line options, possibly with supporting configuration files
8139 generated as needed (@pxref{Defining Services}).
8141 @cindex customization, of services
8142 @findex modify-services
8143 Occasionally, instead of using the base services as is, you will want to
8144 customize them. To do this, use @code{modify-services} (@pxref{Service
8145 Reference, @code{modify-services}}) to modify the list.
8147 For example, suppose you want to modify @code{guix-daemon} and Mingetty
8148 (the console log-in) in the @var{%base-services} list (@pxref{Base
8149 Services, @code{%base-services}}). To do that, you can write the
8150 following in your operating system declaration:
8153 (define %my-services
8154 ;; My very own list of services.
8155 (modify-services %base-services
8156 (guix-service-type config =>
8159 (use-substitutes? #f)
8160 (extra-options '("--gc-keep-derivations"))))
8161 (mingetty-service-type config =>
8162 (mingetty-configuration
8163 (inherit config)))))
8167 (services %my-services))
8170 This changes the configuration---i.e., the service parameters---of the
8171 @code{guix-service-type} instance, and that of all the
8172 @code{mingetty-service-type} instances in the @var{%base-services} list.
8173 Observe how this is accomplished: first, we arrange for the original
8174 configuration to be bound to the identifier @code{config} in the
8175 @var{body}, and then we write the @var{body} so that it evaluates to the
8176 desired configuration. In particular, notice how we use @code{inherit}
8177 to create a new configuration which has the same values as the old
8178 configuration, but with a few modifications.
8180 @cindex encrypted disk
8181 The configuration for a typical ``desktop'' usage, with an encrypted
8182 root partition, the X11 display
8183 server, GNOME and Xfce (users can choose which of these desktop
8184 environments to use at the log-in screen by pressing @kbd{F1}), network
8185 management, power management, and more, would look like this:
8188 @include os-config-desktop.texi
8191 A graphical UEFI system with a choice of lightweight window managers
8192 instead of full-blown desktop environments would look like this:
8195 @include os-config-lightweight-desktop.texi
8198 @xref{Desktop Services}, for the exact list of services provided by
8199 @var{%desktop-services}. @xref{X.509 Certificates}, for background
8200 information about the @code{nss-certs} package that is used here.
8202 Again, @var{%desktop-services} is just a list of service objects. If
8203 you want to remove services from there, you can do so using the
8204 procedures for list filtering (@pxref{SRFI-1 Filtering and
8205 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
8206 following expression returns a list that contains all the services in
8207 @var{%desktop-services} minus the Avahi service:
8210 (remove (lambda (service)
8211 (eq? (service-kind service) avahi-service-type))
8215 @unnumberedsubsubsec Instantiating the System
8217 Assuming the @code{operating-system} declaration
8218 is stored in the @file{my-system-config.scm}
8219 file, the @command{guix system reconfigure my-system-config.scm} command
8220 instantiates that configuration, and makes it the default GRUB boot
8221 entry (@pxref{Invoking guix system}).
8223 The normal way to change the system configuration is by updating this
8224 file and re-running @command{guix system reconfigure}. One should never
8225 have to touch files in @file{/etc} or to run commands that modify the
8226 system state such as @command{useradd} or @command{grub-install}. In
8227 fact, you must avoid that since that would not only void your warranty
8228 but also prevent you from rolling back to previous versions of your
8229 system, should you ever need to.
8231 @cindex roll-back, of the operating system
8232 Speaking of roll-back, each time you run @command{guix system
8233 reconfigure}, a new @dfn{generation} of the system is created---without
8234 modifying or deleting previous generations. Old system generations get
8235 an entry in the bootloader boot menu, allowing you to boot them in case
8236 something went wrong with the latest generation. Reassuring, no? The
8237 @command{guix system list-generations} command lists the system
8238 generations available on disk. It is also possible to roll back the
8239 system via the commands @command{guix system roll-back} and
8240 @command{guix system switch-generation}.
8242 Although the command @command{guix system reconfigure} will not modify
8243 previous generations, must take care when the current generation is not
8244 the latest (e.g., after invoking @command{guix system roll-back}), since
8245 the operation might overwrite a later generation (@pxref{Invoking guix
8248 @unnumberedsubsubsec The Programming Interface
8250 At the Scheme level, the bulk of an @code{operating-system} declaration
8251 is instantiated with the following monadic procedure (@pxref{The Store
8254 @deffn {Monadic Procedure} operating-system-derivation os
8255 Return a derivation that builds @var{os}, an @code{operating-system}
8256 object (@pxref{Derivations}).
8258 The output of the derivation is a single directory that refers to all
8259 the packages, configuration files, and other supporting files needed to
8260 instantiate @var{os}.
8263 This procedure is provided by the @code{(gnu system)} module. Along
8264 with @code{(gnu services)} (@pxref{Services}), this module contains the
8265 guts of GuixSD. Make sure to visit it!
8268 @node operating-system Reference
8269 @subsection @code{operating-system} Reference
8271 This section summarizes all the options available in
8272 @code{operating-system} declarations (@pxref{Using the Configuration
8275 @deftp {Data Type} operating-system
8276 This is the data type representing an operating system configuration.
8277 By that, we mean all the global system configuration, not per-user
8278 configuration (@pxref{Using the Configuration System}).
8281 @item @code{kernel} (default: @var{linux-libre})
8282 The package object of the operating system kernel to use@footnote{Currently
8283 only the Linux-libre kernel is supported. In the future, it will be
8284 possible to use the GNU@tie{}Hurd.}.
8286 @item @code{kernel-arguments} (default: @code{'()})
8287 List of strings or gexps representing additional arguments to pass on
8288 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
8290 @item @code{bootloader}
8291 The system bootloader configuration object. @xref{Bootloader Configuration}.
8293 @item @code{initrd} (default: @code{base-initrd})
8295 @cindex initial RAM disk
8296 A two-argument monadic procedure that returns an initial RAM disk for
8297 the Linux kernel. @xref{Initial RAM Disk}.
8299 @item @code{firmware} (default: @var{%base-firmware})
8301 List of firmware packages loadable by the operating system kernel.
8303 The default includes firmware needed for Atheros- and Broadcom-based
8304 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
8305 respectively). @xref{Hardware Considerations}, for more info on
8308 @item @code{host-name}
8311 @item @code{hosts-file}
8313 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
8314 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
8315 Reference Manual}). The default is a file with entries for
8316 @code{localhost} and @var{host-name}.
8318 @item @code{mapped-devices} (default: @code{'()})
8319 A list of mapped devices. @xref{Mapped Devices}.
8321 @item @code{file-systems}
8322 A list of file systems. @xref{File Systems}.
8324 @item @code{swap-devices} (default: @code{'()})
8325 @cindex swap devices
8326 A list of strings identifying devices or files to be used for ``swap
8327 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
8328 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
8329 It is possible to specify a swap file in a file system on a mapped
8330 device, provided that the necessary device mapping and file system are
8331 also specified. @xref{Mapped Devices} and @ref{File Systems}.
8333 @item @code{users} (default: @code{%base-user-accounts})
8334 @itemx @code{groups} (default: @var{%base-groups})
8335 List of user accounts and groups. @xref{User Accounts}.
8337 @item @code{skeletons} (default: @code{(default-skeletons)})
8338 A list target file name/file-like object tuples (@pxref{G-Expressions,
8339 file-like objects}). These are the skeleton files that will be added to
8340 the home directory of newly-created user accounts.
8342 For instance, a valid value may look like this:
8345 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
8346 (".guile" ,(plain-file "guile"
8347 "(use-modules (ice-9 readline))
8348 (activate-readline)")))
8351 @item @code{issue} (default: @var{%default-issue})
8352 A string denoting the contents of the @file{/etc/issue} file, which is
8353 displayed when users log in on a text console.
8355 @item @code{packages} (default: @var{%base-packages})
8356 The set of packages installed in the global profile, which is accessible
8357 at @file{/run/current-system/profile}.
8359 The default set includes core utilities and it is good practice to
8360 install non-core utilities in user profiles (@pxref{Invoking guix
8363 @item @code{timezone}
8364 A timezone identifying string---e.g., @code{"Europe/Paris"}.
8366 You can run the @command{tzselect} command to find out which timezone
8367 string corresponds to your region. Choosing an invalid timezone name
8368 causes @command{guix system} to fail.
8370 @item @code{locale} (default: @code{"en_US.utf8"})
8371 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
8372 Library Reference Manual}). @xref{Locales}, for more information.
8374 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
8375 The list of locale definitions to be compiled and that may be used at
8376 run time. @xref{Locales}.
8378 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
8379 The list of GNU@tie{}libc packages whose locale data and tools are used
8380 to build the locale definitions. @xref{Locales}, for compatibility
8381 considerations that justify this option.
8383 @item @code{name-service-switch} (default: @var{%default-nss})
8384 Configuration of the libc name service switch (NSS)---a
8385 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
8388 @item @code{services} (default: @var{%base-services})
8389 A list of service objects denoting system services. @xref{Services}.
8391 @item @code{pam-services} (default: @code{(base-pam-services)})
8393 @cindex pluggable authentication modules
8394 Linux @dfn{pluggable authentication module} (PAM) services.
8395 @c FIXME: Add xref to PAM services section.
8397 @item @code{setuid-programs} (default: @var{%setuid-programs})
8398 List of string-valued G-expressions denoting setuid programs.
8399 @xref{Setuid Programs}.
8401 @item @code{sudoers-file} (default: @var{%sudoers-specification})
8402 @cindex sudoers file
8403 The contents of the @file{/etc/sudoers} file as a file-like object
8404 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
8406 This file specifies which users can use the @command{sudo} command, what
8407 they are allowed to do, and what privileges they may gain. The default
8408 is that only @code{root} and members of the @code{wheel} group may use
8415 @subsection File Systems
8417 The list of file systems to be mounted is specified in the
8418 @code{file-systems} field of the operating system declaration
8419 (@pxref{Using the Configuration System}). Each file system is declared
8420 using the @code{file-system} form, like this:
8424 (mount-point "/home")
8425 (device "/dev/sda3")
8429 As usual, some of the fields are mandatory---those shown in the example
8430 above---while others can be omitted. These are described below.
8432 @deftp {Data Type} file-system
8433 Objects of this type represent file systems to be mounted. They
8434 contain the following members:
8438 This is a string specifying the type of the file system---e.g.,
8441 @item @code{mount-point}
8442 This designates the place where the file system is to be mounted.
8445 This names the ``source'' of the file system. By default it is the name
8446 of a node under @file{/dev}, but its meaning depends on the @code{title}
8447 field described below.
8449 @item @code{title} (default: @code{'device})
8450 This is a symbol that specifies how the @code{device} field is to be
8453 When it is the symbol @code{device}, then the @code{device} field is
8454 interpreted as a file name; when it is @code{label}, then @code{device}
8455 is interpreted as a partition label name; when it is @code{uuid},
8456 @code{device} is interpreted as a partition unique identifier (UUID).
8458 UUIDs may be converted from their string representation (as shown by the
8459 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8460 @code{uuid} form expects 16-byte UUIDs as defined in
8461 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8462 form of UUID used by the ext2 family of file systems and others, but it
8463 is different from ``UUIDs'' found in FAT file systems, for instance.},
8468 (mount-point "/home")
8471 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8474 The @code{label} and @code{uuid} options offer a way to refer to disk
8475 partitions without having to hard-code their actual device
8476 name@footnote{Note that, while it is tempting to use
8477 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8478 result, this is not recommended: These special device nodes are created
8479 by the udev daemon and may be unavailable at the time the device is
8482 However, when the source of a file system is a mapped device (@pxref{Mapped
8483 Devices}), its @code{device} field @emph{must} refer to the mapped
8484 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8485 @code{title} must be set to @code{'device}. This is required so that
8486 the system knows that mounting the file system depends on having the
8487 corresponding device mapping established.
8489 @item @code{flags} (default: @code{'()})
8490 This is a list of symbols denoting mount flags. Recognized flags
8491 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8492 access to special files), @code{no-suid} (ignore setuid and setgid
8493 bits), and @code{no-exec} (disallow program execution.)
8495 @item @code{options} (default: @code{#f})
8496 This is either @code{#f}, or a string denoting mount options.
8498 @item @code{mount?} (default: @code{#t})
8499 This value indicates whether to automatically mount the file system when
8500 the system is brought up. When set to @code{#f}, the file system gets
8501 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8502 is not automatically mounted.
8504 @item @code{needed-for-boot?} (default: @code{#f})
8505 This Boolean value indicates whether the file system is needed when
8506 booting. If that is true, then the file system is mounted when the
8507 initial RAM disk (initrd) is loaded. This is always the case, for
8508 instance, for the root file system.
8510 @item @code{check?} (default: @code{#t})
8511 This Boolean indicates whether the file system needs to be checked for
8512 errors before being mounted.
8514 @item @code{create-mount-point?} (default: @code{#f})
8515 When true, the mount point is created if it does not exist yet.
8517 @item @code{dependencies} (default: @code{'()})
8518 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8519 representing file systems that must be mounted or mapped devices that
8520 must be opened before (and unmounted or closed after) this one.
8522 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8523 a dependency of @file{/sys/fs/cgroup/cpu} and
8524 @file{/sys/fs/cgroup/memory}.
8526 Another example is a file system that depends on a mapped device, for
8527 example for an encrypted partition (@pxref{Mapped Devices}).
8531 The @code{(gnu system file-systems)} exports the following useful
8534 @defvr {Scheme Variable} %base-file-systems
8535 These are essential file systems that are required on normal systems,
8536 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8537 below.) Operating system declarations should always contain at least
8541 @defvr {Scheme Variable} %pseudo-terminal-file-system
8542 This is the file system to be mounted as @file{/dev/pts}. It supports
8543 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8544 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8545 Manual}). Pseudo-terminals are used by terminal emulators such as
8549 @defvr {Scheme Variable} %shared-memory-file-system
8550 This file system is mounted as @file{/dev/shm} and is used to support
8551 memory sharing across processes (@pxref{Memory-mapped I/O,
8552 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8555 @defvr {Scheme Variable} %immutable-store
8556 This file system performs a read-only ``bind mount'' of
8557 @file{/gnu/store}, making it read-only for all the users including
8558 @code{root}. This prevents against accidental modification by software
8559 running as @code{root} or by system administrators.
8561 The daemon itself is still able to write to the store: it remounts it
8562 read-write in its own ``name space.''
8565 @defvr {Scheme Variable} %binary-format-file-system
8566 The @code{binfmt_misc} file system, which allows handling of arbitrary
8567 executable file types to be delegated to user space. This requires the
8568 @code{binfmt.ko} kernel module to be loaded.
8571 @defvr {Scheme Variable} %fuse-control-file-system
8572 The @code{fusectl} file system, which allows unprivileged users to mount
8573 and unmount user-space FUSE file systems. This requires the
8574 @code{fuse.ko} kernel module to be loaded.
8577 @node Mapped Devices
8578 @subsection Mapped Devices
8580 @cindex device mapping
8581 @cindex mapped devices
8582 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8583 such as a hard disk partition, can be @dfn{mapped} into another device,
8584 usually in @code{/dev/mapper/},
8585 with additional processing over the data that flows through
8586 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8587 concept of a ``mapped device'' and that of a file system: both boil down
8588 to @emph{translating} input/output operations made on a file to
8589 operations on its backing store. Thus, the Hurd implements mapped
8590 devices, like file systems, using the generic @dfn{translator} mechanism
8591 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8592 typical example is encryption device mapping: all writes to the mapped
8593 device are encrypted, and all reads are deciphered, transparently.
8594 Guix extends this notion by considering any device or set of devices that
8595 are @dfn{transformed} in some way to create a new device; for instance,
8596 RAID devices are obtained by @dfn{assembling} several other devices, such
8597 as hard disks or partitions, into a new one that behaves as one partition.
8598 Other examples, not yet implemented, are LVM logical volumes.
8600 Mapped devices are declared using the @code{mapped-device} form,
8601 defined as follows; for examples, see below.
8603 @deftp {Data Type} mapped-device
8604 Objects of this type represent device mappings that will be made when
8605 the system boots up.
8609 This is either a string specifying the name of the block device to be mapped,
8610 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8611 need to be assembled for creating a new one.
8614 This string specifies the name of the resulting mapped device. For
8615 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8616 specifying @code{"my-partition"} leads to the creation of
8617 the @code{"/dev/mapper/my-partition"} device.
8618 For RAID devices of type @code{raid-device-mapping}, the full device name
8619 such as @code{"/dev/md0"} needs to be given.
8622 This must be a @code{mapped-device-kind} object, which specifies how
8623 @var{source} is mapped to @var{target}.
8627 @defvr {Scheme Variable} luks-device-mapping
8628 This defines LUKS block device encryption using the @command{cryptsetup}
8629 command from the package with the same name. It relies on the
8630 @code{dm-crypt} Linux kernel module.
8633 @defvr {Scheme Variable} raid-device-mapping
8634 This defines a RAID device, which is assembled using the @code{mdadm}
8635 command from the package with the same name. It requires a Linux kernel
8636 module for the appropriate RAID level to be loaded, such as @code{raid456}
8637 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8640 @cindex disk encryption
8642 The following example specifies a mapping from @file{/dev/sda3} to
8643 @file{/dev/mapper/home} using LUKS---the
8644 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8645 standard mechanism for disk encryption.
8646 The @file{/dev/mapper/home}
8647 device can then be used as the @code{device} of a @code{file-system}
8648 declaration (@pxref{File Systems}).
8652 (source "/dev/sda3")
8654 (type luks-device-mapping))
8657 Alternatively, to become independent of device numbering, one may obtain
8658 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8662 cryptsetup luksUUID /dev/sda3
8665 and use it as follows:
8669 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8671 (type luks-device-mapping))
8674 @cindex swap encryption
8675 It is also desirable to encrypt swap space, since swap space may contain
8676 sensitive data. One way to accomplish that is to use a swap file in a
8677 file system on a device mapped via LUKS encryption. In this way, the
8678 swap file is encrypted because the entire device is encrypted.
8679 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8681 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8682 may be declared as follows:
8686 (source (list "/dev/sda1" "/dev/sdb1"))
8688 (type raid-device-mapping))
8691 The @file{/dev/md0} device can then be used as the @code{device} of a
8692 @code{file-system} declaration (@pxref{File Systems}).
8693 Note that the RAID level need not be given; it is chosen during the
8694 initial creation and formatting of the RAID device and is determined
8695 automatically later.
8699 @subsection User Accounts
8703 @cindex user accounts
8704 User accounts and groups are entirely managed through the
8705 @code{operating-system} declaration. They are specified with the
8706 @code{user-account} and @code{user-group} forms:
8712 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8714 "video" ;video devices such as webcams
8715 "cdrom")) ;the good ol' CD-ROM
8716 (comment "Bob's sister")
8717 (home-directory "/home/alice"))
8720 When booting or upon completion of @command{guix system reconfigure},
8721 the system ensures that only the user accounts and groups specified in
8722 the @code{operating-system} declaration exist, and with the specified
8723 properties. Thus, account or group creations or modifications made by
8724 directly invoking commands such as @command{useradd} are lost upon
8725 reconfiguration or reboot. This ensures that the system remains exactly
8728 @deftp {Data Type} user-account
8729 Objects of this type represent user accounts. The following members may
8734 The name of the user account.
8738 This is the name (a string) or identifier (a number) of the user group
8739 this account belongs to.
8741 @item @code{supplementary-groups} (default: @code{'()})
8742 Optionally, this can be defined as a list of group names that this
8745 @item @code{uid} (default: @code{#f})
8746 This is the user ID for this account (a number), or @code{#f}. In the
8747 latter case, a number is automatically chosen by the system when the
8750 @item @code{comment} (default: @code{""})
8751 A comment about the account, such as the account owner's full name.
8753 @item @code{home-directory}
8754 This is the name of the home directory for the account.
8756 @item @code{create-home-directory?} (default: @code{#t})
8757 Indicates whether the home directory of this account should be created
8758 if it does not exist yet.
8760 @item @code{shell} (default: Bash)
8761 This is a G-expression denoting the file name of a program to be used as
8762 the shell (@pxref{G-Expressions}).
8764 @item @code{system?} (default: @code{#f})
8765 This Boolean value indicates whether the account is a ``system''
8766 account. System accounts are sometimes treated specially; for instance,
8767 graphical login managers do not list them.
8769 @anchor{user-account-password}
8770 @item @code{password} (default: @code{#f})
8771 You would normally leave this field to @code{#f}, initialize user
8772 passwords as @code{root} with the @command{passwd} command, and then let
8773 users change it with @command{passwd}. Passwords set with
8774 @command{passwd} are of course preserved across reboot and
8777 If you @emph{do} want to have a preset password for an account, then
8778 this field must contain the encrypted password, as a string.
8779 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8780 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8781 Manual}, for information on Guile's @code{crypt} procedure.
8787 User group declarations are even simpler:
8790 (user-group (name "students"))
8793 @deftp {Data Type} user-group
8794 This type is for, well, user groups. There are just a few fields:
8798 The name of the group.
8800 @item @code{id} (default: @code{#f})
8801 The group identifier (a number). If @code{#f}, a new number is
8802 automatically allocated when the group is created.
8804 @item @code{system?} (default: @code{#f})
8805 This Boolean value indicates whether the group is a ``system'' group.
8806 System groups have low numerical IDs.
8808 @item @code{password} (default: @code{#f})
8809 What, user groups can have a password? Well, apparently yes. Unless
8810 @code{#f}, this field specifies the password of the group.
8815 For convenience, a variable lists all the basic user groups one may
8818 @defvr {Scheme Variable} %base-groups
8819 This is the list of basic user groups that users and/or packages expect
8820 to be present on the system. This includes groups such as ``root'',
8821 ``wheel'', and ``users'', as well as groups used to control access to
8822 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8825 @defvr {Scheme Variable} %base-user-accounts
8826 This is the list of basic system accounts that programs may expect to
8827 find on a GNU/Linux system, such as the ``nobody'' account.
8829 Note that the ``root'' account is not included here. It is a
8830 special-case and is automatically added whether or not it is specified.
8837 A @dfn{locale} defines cultural conventions for a particular language
8838 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8839 Reference Manual}). Each locale has a name that typically has the form
8840 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8841 @code{fr_LU.utf8} designates the locale for the French language, with
8842 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8844 @cindex locale definition
8845 Usually, you will want to specify the default locale for the machine
8846 using the @code{locale} field of the @code{operating-system} declaration
8847 (@pxref{operating-system Reference, @code{locale}}).
8849 The selected locale is automatically added to the @dfn{locale
8850 definitions} known to the system if needed, with its codeset inferred
8851 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8852 @code{UTF-8} codeset. Additional locale definitions can be specified in
8853 the @code{locale-definitions} slot of @code{operating-system}---this is
8854 useful, for instance, if the codeset could not be inferred from the
8855 locale name. The default set of locale definitions includes some widely
8856 used locales, but not all the available locales, in order to save space.
8858 For instance, to add the North Frisian locale for Germany, the value of
8862 (cons (locale-definition
8863 (name "fy_DE.utf8") (source "fy_DE"))
8864 %default-locale-definitions)
8867 Likewise, to save space, one might want @code{locale-definitions} to
8868 list only the locales that are actually used, as in:
8871 (list (locale-definition
8872 (name "ja_JP.eucjp") (source "ja_JP")
8873 (charset "EUC-JP")))
8877 The compiled locale definitions are available at
8878 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8879 version, which is the default location where the GNU@tie{}libc provided
8880 by Guix looks for locale data. This can be overridden using the
8881 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8882 @code{LOCPATH} and locale packages}).
8884 The @code{locale-definition} form is provided by the @code{(gnu system
8885 locale)} module. Details are given below.
8887 @deftp {Data Type} locale-definition
8888 This is the data type of a locale definition.
8893 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8894 Reference Manual}, for more information on locale names.
8897 The name of the source for that locale. This is typically the
8898 @code{@var{language}_@var{territory}} part of the locale name.
8900 @item @code{charset} (default: @code{"UTF-8"})
8901 The ``character set'' or ``code set'' for that locale,
8902 @uref{http://www.iana.org/assignments/character-sets, as defined by
8908 @defvr {Scheme Variable} %default-locale-definitions
8909 A list of commonly used UTF-8 locales, used as the default
8910 value of the @code{locale-definitions} field of @code{operating-system}
8914 @cindex normalized codeset in locale names
8915 These locale definitions use the @dfn{normalized codeset} for the part
8916 that follows the dot in the name (@pxref{Using gettextized software,
8917 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8918 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8922 @subsubsection Locale Data Compatibility Considerations
8924 @cindex incompatibility, of locale data
8925 @code{operating-system} declarations provide a @code{locale-libcs} field
8926 to specify the GNU@tie{}libc packages that are used to compile locale
8927 declarations (@pxref{operating-system Reference}). ``Why would I
8928 care?'', you may ask. Well, it turns out that the binary format of
8929 locale data is occasionally incompatible from one libc version to
8932 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8933 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8934 For instance, a program linked against libc version 2.21 is unable to
8935 read locale data produced with libc 2.22; worse, that program
8936 @emph{aborts} instead of simply ignoring the incompatible locale
8937 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8938 the incompatible locale data, which is already an improvement.}.
8939 Similarly, a program linked against libc 2.22 can read most, but not
8940 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8941 data is incompatible); thus calls to @code{setlocale} may fail, but
8942 programs will not abort.
8944 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8945 choose whether and when to upgrade software in their profiles, and might
8946 be using a libc version different from the one the system administrator
8947 used to build the system-wide locale data.
8949 Fortunately, unprivileged users can also install their own locale data
8950 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8951 @code{GUIX_LOCPATH} and locale packages}).
8953 Still, it is best if the system-wide locale data at
8954 @file{/run/current-system/locale} is built for all the libc versions
8955 actually in use on the system, so that all the programs can access
8956 it---this is especially crucial on a multi-user system. To do that, the
8957 administrator can specify several libc packages in the
8958 @code{locale-libcs} field of @code{operating-system}:
8961 (use-package-modules base)
8965 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8968 This example would lead to a system containing locale definitions for
8969 both libc 2.21 and the current version of libc in
8970 @file{/run/current-system/locale}.
8974 @subsection Services
8976 @cindex system services
8977 An important part of preparing an @code{operating-system} declaration is
8978 listing @dfn{system services} and their configuration (@pxref{Using the
8979 Configuration System}). System services are typically daemons launched
8980 when the system boots, or other actions needed at that time---e.g.,
8981 configuring network access.
8983 GuixSD has a broad definition of ``service'' (@pxref{Service
8984 Composition}), but many services are managed by the GNU@tie{}Shepherd
8985 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8986 command allows you to list the available services, show their status,
8987 start and stop them, or do other specific operations (@pxref{Jump
8988 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8994 The above command, run as @code{root}, lists the currently defined
8995 services. The @command{herd doc} command shows a synopsis of the given
9000 Run libc's name service cache daemon (nscd).
9003 The @command{start}, @command{stop}, and @command{restart} sub-commands
9004 have the effect you would expect. For instance, the commands below stop
9005 the nscd service and restart the Xorg display server:
9009 Service nscd has been stopped.
9010 # herd restart xorg-server
9011 Service xorg-server has been stopped.
9012 Service xorg-server has been started.
9015 The following sections document the available services, starting with
9016 the core services, that may be used in an @code{operating-system}
9020 * Base Services:: Essential system services.
9021 * Scheduled Job Execution:: The mcron service.
9022 * Log Rotation:: The rottlog service.
9023 * Networking Services:: Network setup, SSH daemon, etc.
9024 * X Window:: Graphical display.
9025 * Printing Services:: Local and remote printer support.
9026 * Desktop Services:: D-Bus and desktop services.
9027 * Database Services:: SQL databases.
9028 * Mail Services:: IMAP, POP3, SMTP, and all that.
9029 * Messaging Services:: Messaging services.
9030 * Monitoring Services:: Monitoring services.
9031 * Kerberos Services:: Kerberos services.
9032 * Web Services:: Web servers.
9033 * DNS Services:: DNS daemons.
9034 * VPN Services:: VPN daemons.
9035 * Network File System:: NFS related services.
9036 * Continuous Integration:: The Cuirass service.
9037 * Power management Services:: The TLP tool.
9038 * Miscellaneous Services:: Other services.
9042 @subsubsection Base Services
9044 The @code{(gnu services base)} module provides definitions for the basic
9045 services that one expects from the system. The services exported by
9046 this module are listed below.
9048 @defvr {Scheme Variable} %base-services
9049 This variable contains a list of basic services (@pxref{Service Types
9050 and Services}, for more information on service objects) one would
9051 expect from the system: a login service (mingetty) on each tty, syslogd,
9052 the libc name service cache daemon (nscd), the udev device manager, and
9055 This is the default value of the @code{services} field of
9056 @code{operating-system} declarations. Usually, when customizing a
9057 system, you will want to append services to @var{%base-services}, like
9061 (cons* (avahi-service) (lsh-service) %base-services)
9065 @defvr {Scheme Variable} special-files-service-type
9066 This is the service that sets up ``special files'' such as
9067 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
9069 The value associated with @code{special-files-service-type} services
9070 must be a list of tuples where the first element is the ``special file''
9071 and the second element is its target. By default it is:
9073 @cindex @file{/bin/sh}
9074 @cindex @file{sh}, in @file{/bin}
9076 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
9079 @cindex @file{/usr/bin/env}
9080 @cindex @file{env}, in @file{/usr/bin}
9081 If you want to add, say, @code{/usr/bin/env} to your system, you can
9085 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
9086 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
9089 Since this is part of @code{%base-services}, you can use
9090 @code{modify-services} to customize the set of special files
9091 (@pxref{Service Reference, @code{modify-services}}). But the simple way
9092 to add a special file is @i{via} the @code{extra-special-file} procedure
9096 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
9097 Use @var{target} as the ``special file'' @var{file}.
9099 For example, adding the following lines to the @code{services} field of
9100 your operating system declaration leads to a @file{/usr/bin/env}
9104 (extra-special-file "/usr/bin/env"
9105 (file-append coreutils "/bin/env"))
9109 @deffn {Scheme Procedure} host-name-service @var{name}
9110 Return a service that sets the host name to @var{name}.
9113 @deffn {Scheme Procedure} login-service @var{config}
9114 Return a service to run login according to @var{config}, a
9115 @code{<login-configuration>} object, which specifies the message of the day,
9119 @deftp {Data Type} login-configuration
9120 This is the data type representing the configuration of login.
9125 @cindex message of the day
9126 A file-like object containing the ``message of the day''.
9128 @item @code{allow-empty-passwords?} (default: @code{#t})
9129 Allow empty passwords by default so that first-time users can log in when
9130 the 'root' account has just been created.
9135 @deffn {Scheme Procedure} mingetty-service @var{config}
9136 Return a service to run mingetty according to @var{config}, a
9137 @code{<mingetty-configuration>} object, which specifies the tty to run, among
9141 @deftp {Data Type} mingetty-configuration
9142 This is the data type representing the configuration of Mingetty, which
9143 provides the default implementation of virtual console log-in.
9148 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
9150 @item @code{auto-login} (default: @code{#f})
9151 When true, this field must be a string denoting the user name under
9152 which the system automatically logs in. When it is @code{#f}, a
9153 user name and password must be entered to log in.
9155 @item @code{login-program} (default: @code{#f})
9156 This must be either @code{#f}, in which case the default log-in program
9157 is used (@command{login} from the Shadow tool suite), or a gexp denoting
9158 the name of the log-in program.
9160 @item @code{login-pause?} (default: @code{#f})
9161 When set to @code{#t} in conjunction with @var{auto-login}, the user
9162 will have to press a key before the log-in shell is launched.
9164 @item @code{mingetty} (default: @var{mingetty})
9165 The Mingetty package to use.
9170 @deffn {Scheme Procedure} agetty-service @var{config}
9171 Return a service to run agetty according to @var{config}, an
9172 @code{<agetty-configuration>} object, which specifies the tty to run,
9176 @deftp {Data Type} agetty-configuration
9177 This is the data type representing the configuration of agetty, which
9178 implements virtual and serial console log-in. See the @code{agetty(8)}
9179 man page for more information.
9184 The name of the console this agetty runs on, as a string---e.g.,
9185 @code{"ttyS0"}. This argument is mandatory.
9187 @item @code{baud-rate} (default: @code{#f})
9188 A string containing a comma-separated list of one or more baud rates, in
9191 @item @code{term} (default: @code{#f})
9192 A string containing the value used for the @code{TERM} environment
9195 @item @code{eight-bits?} (default: @code{#f})
9196 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
9199 @item @code{auto-login} (default: @code{#f})
9200 When passed a login name, as a string, the specified user will be logged
9201 in automatically without prompting for their login name or password.
9203 @item @code{no-reset?} (default: @code{#f})
9204 When @code{#t}, don't reset terminal cflags (control modes).
9206 @item @code{host} (default: @code{#f})
9207 This accepts a string containing the "login_host", which will be written
9208 into the @file{/var/run/utmpx} file.
9210 @item @code{remote?} (default: @code{#f})
9211 When set to @code{#t} in conjunction with @var{host}, this will add an
9212 @code{-r} fakehost option to the command line of the login program
9213 specified in @var{login-program}.
9215 @item @code{flow-control?} (default: @code{#f})
9216 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
9218 @item @code{no-issue?} (default: @code{#f})
9219 When set to @code{#t}, the contents of the @file{/etc/issue} file will
9220 not be displayed before presenting the login prompt.
9222 @item @code{init-string} (default: @code{#f})
9223 This accepts a string that will be sent to the tty or modem before
9224 sending anything else. It can be used to initialize a modem.
9226 @item @code{no-clear?} (default: @code{#f})
9227 When set to @code{#t}, agetty will not clear the screen before showing
9230 @item @code{login-program} (default: (file-append shadow "/bin/login"))
9231 This must be either a gexp denoting the name of a log-in program, or
9232 unset, in which case the default value is the @command{login} from the
9235 @item @code{local-line} (default: @code{#f})
9236 Control the CLOCAL line flag. This accepts one of three symbols as
9237 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
9238 the default value chosen by agetty is @code{'auto}.
9240 @item @code{extract-baud?} (default: @code{#f})
9241 When set to @code{#t}, instruct agetty to try to extract the baud rate
9242 from the status messages produced by certain types of modems.
9244 @item @code{skip-login?} (default: @code{#f})
9245 When set to @code{#t}, do not prompt the user for a login name. This
9246 can be used with @var{login-program} field to use non-standard login
9249 @item @code{no-newline?} (default: @code{#f})
9250 When set to @code{#t}, do not print a newline before printing the
9251 @file{/etc/issue} file.
9253 @c Is this dangerous only when used with login-program, or always?
9254 @item @code{login-options} (default: @code{#f})
9255 This option accepts a string containing options that are passed to the
9256 login program. When used with the @var{login-program}, be aware that a
9257 malicious user could try to enter a login name containing embedded
9258 options that could be parsed by the login program.
9260 @item @code{login-pause} (default: @code{#f})
9261 When set to @code{#t}, wait for any key before showing the login prompt.
9262 This can be used in conjunction with @var{auto-login} to save memory by
9263 lazily spawning shells.
9265 @item @code{chroot} (default: @code{#f})
9266 Change root to the specified directory. This option accepts a directory
9269 @item @code{hangup?} (default: @code{#f})
9270 Use the Linux system call @code{vhangup} to do a virtual hangup of the
9273 @item @code{keep-baud?} (default: @code{#f})
9274 When set to @code{#t}, try to keep the existing baud rate. The baud
9275 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
9278 @item @code{timeout} (default: @code{#f})
9279 When set to an integer value, terminate if no user name could be read
9280 within @var{timeout} seconds.
9282 @item @code{detect-case?} (default: @code{#f})
9283 When set to @code{#t}, turn on support for detecting an uppercase-only
9284 terminal. This setting will detect a login name containing only
9285 uppercase letters as indicating an uppercase-only terminal and turn on
9286 some upper-to-lower case conversions. Note that this will not support
9289 @item @code{wait-cr?} (default: @code{#f})
9290 When set to @code{#t}, wait for the user or modem to send a
9291 carriage-return or linefeed character before displaying
9292 @file{/etc/issue} or login prompt. This is typically used with the
9293 @var{init-string} option.
9295 @item @code{no-hints?} (default: @code{#f})
9296 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
9299 @item @code{no-hostname?} (default: @code{#f})
9300 By default, the hostname is printed. When this option is set to
9301 @code{#t}, no hostname will be shown at all.
9303 @item @code{long-hostname?} (default: @code{#f})
9304 By default, the hostname is only printed until the first dot. When this
9305 option is set to @code{#t}, the fully qualified hostname by
9306 @code{gethostname} or @code{getaddrinfo} is shown.
9308 @item @code{erase-characters} (default: @code{#f})
9309 This option accepts a string of additional characters that should be
9310 interpreted as backspace when the user types their login name.
9312 @item @code{kill-characters} (default: @code{#f})
9313 This option accepts a string that should be interpreted to mean "ignore
9314 all previous characters" (also called a "kill" character) when the types
9317 @item @code{chdir} (default: @code{#f})
9318 This option accepts, as a string, a directory path that will be changed
9321 @item @code{delay} (default: @code{#f})
9322 This options accepts, as an integer, the number of seconds to sleep
9323 before opening the tty and displaying the login prompt.
9325 @item @code{nice} (default: @code{#f})
9326 This option accepts, as an integer, the nice value with which to run the
9327 @command{login} program.
9329 @item @code{extra-options} (default: @code{'()})
9330 This option provides an "escape hatch" for the user to provide arbitrary
9331 command-line arguments to @command{agetty} as a list of strings.
9336 @deffn {Scheme Procedure} kmscon-service-type @var{config}
9337 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
9338 according to @var{config}, a @code{<kmscon-configuration>} object, which
9339 specifies the tty to run, among other things.
9342 @deftp {Data Type} kmscon-configuration
9343 This is the data type representing the configuration of Kmscon, which
9344 implements virtual console log-in.
9348 @item @code{virtual-terminal}
9349 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
9351 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
9352 A gexp denoting the name of the log-in program. The default log-in program is
9353 @command{login} from the Shadow tool suite.
9355 @item @code{login-arguments} (default: @code{'("-p")})
9356 A list of arguments to pass to @command{login}.
9358 @item @code{hardware-acceleration?} (default: #f)
9359 Whether to use hardware acceleration.
9361 @item @code{kmscon} (default: @var{kmscon})
9362 The Kmscon package to use.
9367 @cindex name service cache daemon
9369 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
9370 [#:name-services '()]
9371 Return a service that runs the libc name service cache daemon (nscd) with the
9372 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
9373 Service Switch}, for an example.
9376 @defvr {Scheme Variable} %nscd-default-configuration
9377 This is the default @code{<nscd-configuration>} value (see below) used
9378 by @code{nscd-service}. It uses the caches defined by
9379 @var{%nscd-default-caches}; see below.
9382 @deftp {Data Type} nscd-configuration
9383 This is the data type representing the name service cache daemon (nscd)
9388 @item @code{name-services} (default: @code{'()})
9389 List of packages denoting @dfn{name services} that must be visible to
9390 the nscd---e.g., @code{(list @var{nss-mdns})}.
9392 @item @code{glibc} (default: @var{glibc})
9393 Package object denoting the GNU C Library providing the @command{nscd}
9396 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
9397 Name of the nscd log file. This is where debugging output goes when
9398 @code{debug-level} is strictly positive.
9400 @item @code{debug-level} (default: @code{0})
9401 Integer denoting the debugging levels. Higher numbers mean that more
9402 debugging output is logged.
9404 @item @code{caches} (default: @var{%nscd-default-caches})
9405 List of @code{<nscd-cache>} objects denoting things to be cached; see
9411 @deftp {Data Type} nscd-cache
9412 Data type representing a cache database of nscd and its parameters.
9416 @item @code{database}
9417 This is a symbol representing the name of the database to be cached.
9418 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
9419 @code{services}, which designate the corresponding NSS database
9420 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
9422 @item @code{positive-time-to-live}
9423 @itemx @code{negative-time-to-live} (default: @code{20})
9424 A number representing the number of seconds during which a positive or
9425 negative lookup result remains in cache.
9427 @item @code{check-files?} (default: @code{#t})
9428 Whether to check for updates of the files corresponding to
9431 For instance, when @var{database} is @code{hosts}, setting this flag
9432 instructs nscd to check for updates in @file{/etc/hosts} and to take
9435 @item @code{persistent?} (default: @code{#t})
9436 Whether the cache should be stored persistently on disk.
9438 @item @code{shared?} (default: @code{#t})
9439 Whether the cache should be shared among users.
9441 @item @code{max-database-size} (default: 32@tie{}MiB)
9442 Maximum size in bytes of the database cache.
9444 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9445 @c settings, so leave them out.
9450 @defvr {Scheme Variable} %nscd-default-caches
9451 List of @code{<nscd-cache>} objects used by default by
9452 @code{nscd-configuration} (see above).
9454 It enables persistent and aggressive caching of service and host name
9455 lookups. The latter provides better host name lookup performance,
9456 resilience in the face of unreliable name servers, and also better
9457 privacy---often the result of host name lookups is in local cache, so
9458 external name servers do not even need to be queried.
9461 @anchor{syslog-configuration-type}
9464 @deftp {Data Type} syslog-configuration
9465 This data type represents the configuration of the syslog daemon.
9468 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9469 The syslog daemon to use.
9471 @item @code{config-file} (default: @code{%default-syslog.conf})
9472 The syslog configuration file to use.
9477 @anchor{syslog-service}
9479 @deffn {Scheme Procedure} syslog-service @var{config}
9480 Return a service that runs a syslog daemon according to @var{config}.
9482 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9483 information on the configuration file syntax.
9486 @anchor{guix-configuration-type}
9487 @deftp {Data Type} guix-configuration
9488 This data type represents the configuration of the Guix build daemon.
9489 @xref{Invoking guix-daemon}, for more information.
9492 @item @code{guix} (default: @var{guix})
9493 The Guix package to use.
9495 @item @code{build-group} (default: @code{"guixbuild"})
9496 Name of the group for build user accounts.
9498 @item @code{build-accounts} (default: @code{10})
9499 Number of build user accounts to create.
9501 @item @code{authorize-key?} (default: @code{#t})
9502 @cindex substitutes, authorization thereof
9503 Whether to authorize the substitute keys listed in
9504 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9505 (@pxref{Substitutes}).
9507 @vindex %default-authorized-guix-keys
9508 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9509 The list of authorized key files for archive imports, as a list of
9510 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9511 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9513 @item @code{use-substitutes?} (default: @code{#t})
9514 Whether to use substitutes.
9516 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9517 The list of URLs where to look for substitutes by default.
9519 @item @code{max-silent-time} (default: @code{0})
9520 @itemx @code{timeout} (default: @code{0})
9521 The number of seconds of silence and the number of seconds of activity,
9522 respectively, after which a build process times out. A value of zero
9523 disables the timeout.
9525 @item @code{extra-options} (default: @code{'()})
9526 List of extra command-line options for @command{guix-daemon}.
9528 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9529 File where @command{guix-daemon}'s standard output and standard error
9532 @item @code{lsof} (default: @var{lsof})
9533 The lsof package to use.
9535 @item @code{http-proxy} (default: @code{#f})
9536 The HTTP proxy used for downloading fixed-output derivations and
9539 @item @code{tmpdir} (default: @code{#f})
9540 A directory path where the @command{guix-daemon} will perform builds.
9545 @deffn {Scheme Procedure} guix-service @var{config}
9546 Return a service that runs the Guix build daemon according to
9550 @deffn {Scheme Procedure} udev-service [#:udev udev]
9551 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9554 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9555 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9559 @defvr {Scheme Variable} %random-seed-file
9560 This is the name of the file where some random bytes are saved by
9561 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9562 It defaults to @file{/var/lib/random-seed}.
9567 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9568 @cindex keyboard layout
9569 Return a service to load console keymaps from @var{files} using
9570 @command{loadkeys} command. Most likely, you want to load some default
9571 keymap, which can be done like this:
9574 (console-keymap-service "dvorak")
9577 Or, for example, for a Swedish keyboard, you may need to combine
9578 the following keymaps:
9580 (console-keymap-service "se-lat6" "se-fi-lat6")
9583 Also you can specify a full file name (or file names) of your keymap(s).
9584 See @code{man loadkeys} for details.
9590 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9592 Run @var{gpm}, the general-purpose mouse daemon, with the given
9593 command-line @var{options}. GPM allows users to use the mouse in the console,
9594 notably to select, copy, and paste text. The default value of @var{options}
9595 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9597 This service is not part of @var{%base-services}.
9600 @anchor{guix-publish-service-type}
9601 @deffn {Scheme Variable} guix-publish-service-type
9602 This is the service type for @command{guix publish} (@pxref{Invoking
9603 guix publish}). Its value must be a @code{guix-configuration}
9604 object, as described below.
9606 This assumes that @file{/etc/guix} already contains a signing key pair as
9607 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9608 archive}). If that is not the case, the service will fail to start.
9611 @deftp {Data Type} guix-publish-configuration
9612 Data type representing the configuration of the @code{guix publish}
9616 @item @code{guix} (default: @code{guix})
9617 The Guix package to use.
9619 @item @code{port} (default: @code{80})
9620 The TCP port to listen for connections.
9622 @item @code{host} (default: @code{"localhost"})
9623 The host (and thus, network interface) to listen to. Use
9624 @code{"0.0.0.0"} to listen on all the network interfaces.
9626 @item @code{compression-level} (default: @code{3})
9627 The gzip compression level at which substitutes are compressed. Use
9628 @code{0} to disable compression altogether, and @code{9} to get the best
9629 compression ratio at the expense of increased CPU usage.
9631 @item @code{nar-path} (default: @code{"nar"})
9632 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9633 publish, @code{--nar-path}}, for details.
9635 @item @code{cache} (default: @code{#f})
9636 When it is @code{#f}, disable caching and instead generate archives on
9637 demand. Otherwise, this should be the name of a directory---e.g.,
9638 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
9639 archives and meta-data ready to be sent. @xref{Invoking guix publish,
9640 @option{--cache}}, for more information on the tradeoffs involved.
9642 @item @code{workers} (default: @code{#f})
9643 When it is an integer, this is the number of worker threads used for
9644 caching; when @code{#f}, the number of processors is used.
9645 @xref{Invoking guix publish, @option{--workers}}, for more information.
9647 @item @code{ttl} (default: @code{#f})
9648 When it is an integer, this denotes the @dfn{time-to-live} of the
9649 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
9654 @anchor{rngd-service}
9655 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9656 [#:device "/dev/hwrng"]
9657 Return a service that runs the @command{rngd} program from @var{rng-tools}
9658 to add @var{device} to the kernel's entropy pool. The service will fail if
9659 @var{device} does not exist.
9662 @anchor{pam-limits-service}
9663 @cindex session limits
9666 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9668 Return a service that installs a configuration file for the
9669 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9670 @code{pam_limits} module}. The procedure optionally takes a list of
9671 @code{pam-limits-entry} values, which can be used to specify
9672 @code{ulimit} limits and nice priority limits to user sessions.
9674 The following limits definition sets two hard and soft limits for all
9675 login sessions of users in the @code{realtime} group:
9680 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9681 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9684 The first entry increases the maximum realtime priority for
9685 non-privileged processes; the second entry lifts any restriction of the
9686 maximum address space that can be locked in memory. These settings are
9687 commonly used for real-time audio systems.
9690 @node Scheduled Job Execution
9691 @subsubsection Scheduled Job Execution
9695 @cindex scheduling jobs
9696 The @code{(gnu services mcron)} module provides an interface to
9697 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9698 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9699 Unix @command{cron} daemon; the main difference is that it is
9700 implemented in Guile Scheme, which provides a lot of flexibility when
9701 specifying the scheduling of jobs and their actions.
9703 The example below defines an operating system that runs the
9704 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9705 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9706 well as the @command{mkid} command on behalf of an unprivileged user
9707 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9708 gexps to introduce job definitions that are passed to mcron
9709 (@pxref{G-Expressions}).
9712 (use-modules (guix) (gnu) (gnu services mcron))
9713 (use-package-modules base idutils)
9715 (define updatedb-job
9716 ;; Run 'updatedb' at 3AM every day. Here we write the
9717 ;; job's action as a Scheme procedure.
9718 #~(job '(next-hour '(3))
9720 (execl (string-append #$findutils "/bin/updatedb")
9722 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9724 (define garbage-collector-job
9725 ;; Collect garbage 5 minutes after midnight every day.
9726 ;; The job's action is a shell command.
9727 #~(job "5 0 * * *" ;Vixie cron syntax
9731 ;; Update the index database as user "charlie" at 12:15PM
9732 ;; and 19:15PM. This runs from the user's home directory.
9733 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9734 (string-append #$idutils "/bin/mkid src")
9739 (services (cons (mcron-service (list garbage-collector-job
9745 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9746 for more information on mcron job specifications. Below is the
9747 reference of the mcron service.
9749 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9750 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9751 list of gexps denoting mcron job specifications.
9753 This is a shorthand for:
9755 (service mcron-service-type
9756 (mcron-configuration (mcron mcron) (jobs jobs)))
9760 @defvr {Scheme Variable} mcron-service-type
9761 This is the type of the @code{mcron} service, whose value is an
9762 @code{mcron-configuration} object.
9764 This service type can be the target of a service extension that provides
9765 it additional job specifications (@pxref{Service Composition}). In
9766 other words, it is possible to define services that provide additional
9770 @deftp {Data Type} mcron-configuration
9771 Data type representing the configuration of mcron.
9774 @item @code{mcron} (default: @var{mcron2})
9775 The mcron package to use.
9778 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9779 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9780 specifications,, mcron, GNU@tie{}mcron}).
9786 @subsubsection Log Rotation
9789 @cindex log rotation
9791 Log files such as those found in @file{/var/log} tend to grow endlessly,
9792 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9793 their contents in separate files, possibly compressed. The @code{(gnu
9794 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9795 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9797 The example below defines an operating system that provides log rotation
9798 with the default settings, for commonly encountered log files.
9801 (use-modules (guix) (gnu))
9802 (use-service-modules admin mcron)
9803 (use-package-modules base idutils)
9807 (services (cons* (mcron-service)
9808 (service rottlog-service-type)
9812 @defvr {Scheme Variable} rottlog-service-type
9813 This is the type of the Rottlog service, whose value is a
9814 @code{rottlog-configuration} object.
9816 Other services can extend this one with new @code{log-rotation} objects
9817 (see below), thereby augmenting the set of files to be rotated.
9819 This service type can define mcron jobs (@pxref{Scheduled Job
9820 Execution}) to run the rottlog service.
9823 @deftp {Data Type} rottlog-configuration
9824 Data type representing the configuration of rottlog.
9827 @item @code{rottlog} (default: @code{rottlog})
9828 The Rottlog package to use.
9830 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9831 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9832 rottlog, GNU Rot[t]log Manual}).
9834 @item @code{rotations} (default: @code{%default-rotations})
9835 A list of @code{log-rotation} objects as defined below.
9838 This is a list of gexps where each gexp corresponds to an mcron job
9839 specification (@pxref{Scheduled Job Execution}).
9843 @deftp {Data Type} log-rotation
9844 Data type representing the rotation of a group of log files.
9846 Taking an example from the Rottlog manual (@pxref{Period Related File
9847 Examples,,, rottlog, GNU Rot[t]log Manual}), a log rotation might be
9853 (files '("/var/log/apache/*"))
9854 (options '("storedir apache-archives"
9860 The list of fields is as follows:
9863 @item @code{frequency} (default: @code{'weekly})
9864 The log rotation frequency, a symbol.
9867 The list of files or file glob patterns to rotate.
9869 @item @code{options} (default: @code{'()})
9870 The list of rottlog options for this rotation (@pxref{Configuration
9871 parameters,,, rottlog, GNU Rot[t]lg Manual}).
9873 @item @code{post-rotate} (default: @code{#f})
9874 Either @code{#f} or a gexp to execute once the rotation has completed.
9878 @defvr {Scheme Variable} %default-rotations
9879 Specifies weekly rotation of @var{%rotated-files} and
9880 a couple of other files.
9883 @defvr {Scheme Variable} %rotated-files
9884 The list of syslog-controlled files to be rotated. By default it is:
9885 @code{'("/var/log/messages" "/var/log/secure")}.
9888 @node Networking Services
9889 @subsubsection Networking Services
9891 The @code{(gnu services networking)} module provides services to configure
9892 the network interface.
9894 @cindex DHCP, networking service
9895 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9896 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9897 Protocol (DHCP) client, on all the non-loopback network interfaces.
9900 @defvr {Scheme Variable} static-networking-service-type
9901 This is the type for statically-configured network interfaces.
9902 @c TODO Document <static-networking> data structures.
9905 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9906 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9907 Return a service that starts @var{interface} with address @var{ip}. If
9908 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9909 it must be a string specifying the default network gateway.
9911 This procedure can be called several times, one for each network
9912 interface of interest. Behind the scenes what it does is extend
9913 @code{static-networking-service-type} with additional network interfaces
9920 @cindex network management
9921 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9922 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9923 management daemon that aims to simplify wired and wireless networking.
9925 This service adds the @var{wicd} package to the global profile, providing
9926 several commands to interact with the daemon and configure networking:
9927 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
9928 and @command{wicd-curses} user interfaces.
9931 @cindex NetworkManager
9933 @defvr {Scheme Variable} network-manager-service-type
9934 This is the service type for the
9935 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
9936 service. The value for this service type is a
9937 @code{network-manager-configuration} record.
9940 @deftp {Data Type} network-manager-configuration
9941 Data type representing the configuration of NetworkManager.
9944 @item @code{network-manager} (default: @code{network-manager})
9945 The NetworkManager package to use.
9947 @item @code{dns} (default: @code{"default"})
9948 Processing mode for DNS, which affects how NetworkManager uses the
9949 @code{resolv.conf} configuration file.
9953 NetworkManager will update @code{resolv.conf} to reflect the nameservers
9954 provided by currently active connections.
9957 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
9958 using a "split DNS" configuration if you are connected to a VPN, and
9959 then update @code{resolv.conf} to point to the local nameserver.
9962 NetworkManager will not modify @code{resolv.conf}.
9969 @deffn {Scheme Variable} connman-service-type
9970 This is the service type to run @url{https://01.org/connman,Connman},
9971 a network connection manager.
9973 Its value must be an
9974 @code{connman-configuration} record as in this example:
9977 (service connman-service-type
9978 (connman-configuration
9982 See below for details about @code{connman-configuration}.
9985 @deftp {Data Type} connman-configuration
9986 Data Type representing the configuration of connman.
9989 @item @code{connman} (default: @var{connman})
9990 The connman package to use.
9992 @item @code{disable-vpn?} (default: @code{#f})
9993 When true, enable connman's vpn plugin.
9997 @cindex WPA Supplicant
9998 @defvr {Scheme Variable} wpa-supplicant-service-type
9999 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
10000 supplicant}, an authentication daemon required to authenticate against
10001 encrypted WiFi or ethernet networks. It is configured to listen for
10004 The value of this service is the @code{wpa-supplicant} package to use.
10005 Thus, it can be instantiated like this:
10008 (use-modules (gnu services networking))
10010 (service wpa-supplicant-service-type)
10015 @cindex real time clock
10016 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
10017 [#:servers @var{%ntp-servers}] @
10018 [#:allow-large-adjustment? #f]
10019 Return a service that runs the daemon from @var{ntp}, the
10020 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
10021 keep the system clock synchronized with that of @var{servers}.
10022 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
10023 make an initial adjustment of more than 1,000 seconds.
10026 @defvr {Scheme Variable} %ntp-servers
10027 List of host names used as the default NTP servers.
10031 @deffn {Scheme variable} inetd-service-type
10032 This service runs the @command{inetd} (@pxref{inetd invocation,,,
10033 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
10034 connections on internet sockets, and lazily starts the specified server
10035 program when a connection is made on one of these sockets.
10037 The value of this service is an @code{inetd-configuration} object. The
10038 following example configures the @command{inetd} daemon to provide the
10039 built-in @command{echo} service, as well as an smtp service which
10040 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
10041 gateway @code{hostname}:
10046 (inetd-configuration
10050 (socket-type 'stream)
10057 (socket-type 'stream)
10061 (program (file-append openssh "/bin/ssh"))
10063 '("ssh" "-qT" "-i" "/path/to/ssh_key"
10064 "-W" "smtp-server:25" "user@@hostname")))))
10067 See below for more details about @code{inetd-configuration}.
10070 @deftp {Data Type} inetd-configuration
10071 Data type representing the configuration of @command{inetd}.
10074 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
10075 The @command{inetd} executable to use.
10077 @item @code{entries} (default: @code{'()})
10078 A list of @command{inetd} service entries. Each entry should be created
10079 by the @code{inetd-entry} constructor.
10083 @deftp {Data Type} inetd-entry
10084 Data type representing an entry in the @command{inetd} configuration.
10085 Each entry corresponds to a socket where @command{inetd} will listen for
10089 @item @code{node} (default: @code{#f})
10090 Optional string, a comma-separated list of local addresses
10091 @command{inetd} should use when listening for this service.
10092 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
10093 description of all options.
10095 A string, the name must correspond to an entry in @code{/etc/services}.
10096 @item @code{socket-type}
10097 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
10099 @item @code{protocol}
10100 A string, must correspond to an entry in @code{/etc/protocols}.
10101 @item @code{wait?} (default: @code{#t})
10102 Whether @command{inetd} should wait for the server to exit before
10103 listening to new service requests.
10105 A string containing the user (and, optionally, group) name of the user
10106 as whom the server should run. The group name can be specified in a
10107 suffix, separated by a colon or period, i.e. @code{"user"},
10108 @code{"user:group"} or @code{"user.group"}.
10109 @item @code{program} (default: @code{"internal"})
10110 The server program which will serve the requests, or @code{"internal"}
10111 if @command{inetd} should use a built-in service.
10112 @item @code{arguments} (default: @code{'()})
10113 A list strings or file-like objects, which are the server program's
10114 arguments, starting with the zeroth argument, i.e. the name of the
10115 program itself. For @command{inetd}'s internal services, this entry
10116 must be @code{'()} or @code{'("internal")}.
10119 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
10120 detailed discussion of each configuration field.
10124 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
10125 Return a service to run the @uref{https://torproject.org, Tor} anonymous
10128 The daemon runs as the @code{tor} unprivileged user. It is passed
10129 @var{config-file}, a file-like object, with an additional @code{User tor} line
10130 and lines for hidden services added via @code{tor-hidden-service}. Run
10131 @command{man tor} for information about the configuration file.
10134 @cindex hidden service
10135 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
10136 Define a new Tor @dfn{hidden service} called @var{name} and implementing
10137 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
10140 '((22 "127.0.0.1:22")
10141 (80 "127.0.0.1:8080"))
10144 In this example, port 22 of the hidden service is mapped to local port 22, and
10145 port 80 is mapped to local port 8080.
10147 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
10148 the @file{hostname} file contains the @code{.onion} host name for the hidden
10151 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
10152 project's documentation} for more information.
10155 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
10156 [#:interface "127.0.0.1"] [#:port 6667] @
10157 [#:extra-settings ""]
10158 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
10159 acts as a gateway between IRC and chat networks.
10161 The daemon will listen to the interface corresponding to the IP address
10162 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
10163 local clients can connect, whereas @code{0.0.0.0} means that connections can
10164 come from any networking interface.
10166 In addition, @var{extra-settings} specifies a string to append to the
10167 configuration file.
10170 Furthermore, @code{(gnu services ssh)} provides the following services.
10174 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
10175 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
10176 [#:allow-empty-passwords? #f] [#:root-login? #f] @
10177 [#:syslog-output? #t] [#:x11-forwarding? #t] @
10178 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
10179 [#:public-key-authentication? #t] [#:initialize? #t]
10180 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
10181 @var{host-key} must designate a file containing the host key, and readable
10184 When @var{daemonic?} is true, @command{lshd} will detach from the
10185 controlling terminal and log its output to syslogd, unless one sets
10186 @var{syslog-output?} to false. Obviously, it also makes lsh-service
10187 depend on existence of syslogd service. When @var{pid-file?} is true,
10188 @command{lshd} writes its PID to the file called @var{pid-file}.
10190 When @var{initialize?} is true, automatically create the seed and host key
10191 upon service activation if they do not exist yet. This may take long and
10192 require interaction.
10194 When @var{initialize?} is false, it is up to the user to initialize the
10195 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
10196 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
10197 basics,,, lsh, LSH Manual}).
10199 When @var{interfaces} is empty, lshd listens for connections on all the
10200 network interfaces; otherwise, @var{interfaces} must be a list of host names
10203 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
10204 passwords, and @var{root-login?} specifies whether to accept log-ins as
10207 The other options should be self-descriptive.
10212 @deffn {Scheme Variable} openssh-service-type
10213 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
10214 shell daemon, @command{sshd}. Its value must be an
10215 @code{openssh-configuration} record as in this example:
10218 (service openssh-service-type
10219 (openssh-configuration
10220 (x11-forwarding? #t)
10221 (permit-root-login 'without-password)
10223 `(("alice" ,(local-file "alice.pub"))
10224 ("bob" ,(local-file "bob.pub"))))))
10227 See below for details about @code{openssh-configuration}.
10229 This service can be extended with extra authorized keys, as in this
10233 (service-extension openssh-service-type
10234 (const `(("charlie"
10235 ,(local-file "charlie.pub")))))
10239 @deftp {Data Type} openssh-configuration
10240 This is the configuration record for OpenSSH's @command{sshd}.
10243 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
10244 Name of the file where @command{sshd} writes its PID.
10246 @item @code{port-number} (default: @code{22})
10247 TCP port on which @command{sshd} listens for incoming connections.
10249 @item @code{permit-root-login} (default: @code{#f})
10250 This field determines whether and when to allow logins as root. If
10251 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
10252 If it's the symbol @code{'without-password}, then root logins are
10253 permitted but not with password-based authentication.
10255 @item @code{allow-empty-passwords?} (default: @code{#f})
10256 When true, users with empty passwords may log in. When false, they may
10259 @item @code{password-authentication?} (default: @code{#t})
10260 When true, users may log in with their password. When false, they have
10261 other authentication methods.
10263 @item @code{public-key-authentication?} (default: @code{#t})
10264 When true, users may log in using public key authentication. When
10265 false, users have to use other authentication method.
10267 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
10268 This is used only by protocol version 2.
10270 @item @code{x11-forwarding?} (default: @code{#f})
10271 When true, forwarding of X11 graphical client connections is
10272 enabled---in other words, @command{ssh} options @option{-X} and
10273 @option{-Y} will work.
10275 @item @code{challenge-response-authentication?} (default: @code{#f})
10276 Specifies whether challenge response authentication is allowed (e.g. via
10279 @item @code{use-pam?} (default: @code{#t})
10280 Enables the Pluggable Authentication Module interface. If set to
10281 @code{#t}, this will enable PAM authentication using
10282 @code{challenge-response-authentication?} and
10283 @code{password-authentication?}, in addition to PAM account and session
10284 module processing for all authentication types.
10286 Because PAM challenge response authentication usually serves an
10287 equivalent role to password authentication, you should disable either
10288 @code{challenge-response-authentication?} or
10289 @code{password-authentication?}.
10291 @item @code{print-last-log?} (default: @code{#t})
10292 Specifies whether @command{sshd} should print the date and time of the
10293 last user login when a user logs in interactively.
10295 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
10296 Configures external subsystems (e.g. file transfer daemon).
10298 This is a list of two-element lists, each of which containing the
10299 subsystem name and a command (with optional arguments) to execute upon
10302 The command @command{internal-sftp} implements an in-process SFTP
10303 server. Alternately, one can specify the @command{sftp-server} command:
10305 (service openssh-service-type
10306 (openssh-configuration
10308 `(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
10311 @item @code{authorized-keys} (default: @code{'()})
10312 @cindex authorized keys, SSH
10313 @cindex SSH authorized keys
10314 This is the list of authorized keys. Each element of the list is a user
10315 name followed by one or more file-like objects that represent SSH public
10319 (openssh-configuration
10321 `(("rekado" ,(local-file "rekado.pub"))
10322 ("chris" ,(local-file "chris.pub"))
10323 ("root" ,(local-file "rekado.pub") ,(local-file "chris.pub")))))
10327 registers the specified public keys for user accounts @code{rekado},
10328 @code{chris}, and @code{root}.
10330 Additional authorized keys can be specified @i{via}
10331 @code{service-extension}.
10333 Note that this does @emph{not} interfere with the use of
10334 @file{~/.ssh/authorized_keys}.
10338 @deffn {Scheme Procedure} dropbear-service [@var{config}]
10339 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
10340 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
10343 For example, to specify a Dropbear service listening on port 1234, add
10344 this call to the operating system's @code{services} field:
10347 (dropbear-service (dropbear-configuration
10348 (port-number 1234)))
10352 @deftp {Data Type} dropbear-configuration
10353 This data type represents the configuration of a Dropbear SSH daemon.
10356 @item @code{dropbear} (default: @var{dropbear})
10357 The Dropbear package to use.
10359 @item @code{port-number} (default: 22)
10360 The TCP port where the daemon waits for incoming connections.
10362 @item @code{syslog-output?} (default: @code{#t})
10363 Whether to enable syslog output.
10365 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
10366 File name of the daemon's PID file.
10368 @item @code{root-login?} (default: @code{#f})
10369 Whether to allow @code{root} logins.
10371 @item @code{allow-empty-passwords?} (default: @code{#f})
10372 Whether to allow empty passwords.
10374 @item @code{password-authentication?} (default: @code{#t})
10375 Whether to enable password-based authentication.
10379 @defvr {Scheme Variable} %facebook-host-aliases
10380 This variable contains a string for use in @file{/etc/hosts}
10381 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
10382 line contains a entry that maps a known server name of the Facebook
10383 on-line service---e.g., @code{www.facebook.com}---to the local
10384 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
10386 This variable is typically used in the @code{hosts-file} field of an
10387 @code{operating-system} declaration (@pxref{operating-system Reference,
10388 @file{/etc/hosts}}):
10391 (use-modules (gnu) (guix))
10394 (host-name "mymachine")
10397 ;; Create a /etc/hosts file with aliases for "localhost"
10398 ;; and "mymachine", as well as for Facebook servers.
10399 (plain-file "hosts"
10400 (string-append (local-host-aliases host-name)
10401 %facebook-host-aliases))))
10404 This mechanism can prevent programs running locally, such as Web
10405 browsers, from accessing Facebook.
10408 The @code{(gnu services avahi)} provides the following definition.
10410 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
10411 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
10412 [#:ipv6? #t] [#:wide-area? #f] @
10413 [#:domains-to-browse '()] [#:debug? #f]
10414 Return a service that runs @command{avahi-daemon}, a system-wide
10415 mDNS/DNS-SD responder that allows for service discovery and
10416 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
10417 extends the name service cache daemon (nscd) so that it can resolve
10418 @code{.local} host names using
10419 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
10420 add the @var{avahi} package to the system profile so that commands such as
10421 @command{avahi-browse} are directly usable.
10423 If @var{host-name} is different from @code{#f}, use that as the host name to
10424 publish for this machine; otherwise, use the machine's actual host name.
10426 When @var{publish?} is true, publishing of host names and services is allowed;
10427 in particular, avahi-daemon will publish the machine's host name and IP
10428 address via mDNS on the local network.
10430 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
10432 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
10436 @deffn {Scheme Variable} openvswitch-service-type
10437 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
10438 service, whose value should be an @code{openvswitch-configuration}
10442 @deftp {Data Type} openvswitch-configuration
10443 Data type representing the configuration of Open vSwitch, a multilayer
10444 virtual switch which is designed to enable massive network automation
10445 through programmatic extension.
10448 @item @code{package} (default: @var{openvswitch})
10449 Package object of the Open vSwitch.
10455 @subsubsection X Window
10458 @cindex X Window System
10459 Support for the X Window graphical display system---specifically
10460 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
10461 there is no @code{xorg-service} procedure. Instead, the X server is
10462 started by the @dfn{login manager}, currently SLiM.
10464 @deftp {Data Type} sddm-configuration
10465 This is the data type representing the sddm service configuration.
10468 @item @code{display-server} (default: "x11")
10469 Select display server to use for the greeter. Valid values are "x11"
10472 @item @code{numlock} (default: "on")
10473 Valid values are "on", "off" or "none".
10475 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
10476 Command to run when halting.
10478 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
10479 Command to run when rebooting.
10481 @item @code{theme} (default "maldives")
10482 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
10484 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
10485 Directory to look for themes.
10487 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
10488 Directory to look for faces.
10490 @item @code{default-path} (default "/run/current-system/profile/bin")
10491 Default PATH to use.
10493 @item @code{minimum-uid} (default 1000)
10494 Minimum UID to display in SDDM.
10496 @item @code{maximum-uid} (default 2000)
10497 Maximum UID to display in SDDM
10499 @item @code{remember-last-user?} (default #t)
10500 Remember last user.
10502 @item @code{remember-last-session?} (default #t)
10503 Remember last session.
10505 @item @code{hide-users} (default "")
10506 Usernames to hide from SDDM greeter.
10508 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10509 Users with shells listed will be hidden from the SDDM greeter.
10511 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10512 Script to run before starting a wayland session.
10514 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10515 Directory to look for desktop files starting wayland sessions.
10517 @item @code{xorg-server-path} (default @code{xorg-start-command})
10518 Path to xorg-server.
10520 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10523 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
10526 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
10527 Script to run after starting xorg-server.
10529 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
10530 Script to run before stopping xorg-server.
10532 @item @code{xsession-command} (default: @code{xinitr })
10533 Script to run before starting a X session.
10535 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
10536 Directory to look for desktop files starting X sessions.
10538 @item @code{minimum-vt} (default: 7)
10541 @item @code{xserver-arguments} (default "-nolisten tcp")
10542 Arguments to pass to xorg-server.
10544 @item @code{auto-login-user} (default "")
10545 User to use for auto-login.
10547 @item @code{auto-login-session} (default "")
10548 Desktop file to use for auto-login.
10550 @item @code{relogin?} (default #f)
10551 Relogin after logout.
10556 @cindex login manager
10557 @deffn {Scheme Procedure} sddm-service config
10558 Return a service that spawns the SDDM graphical login manager for config of
10559 type @code{<sddm-configuration>}.
10562 (sddm-service (sddm-configuration
10563 (auto-login-user "Alice")
10564 (auto-login-session "xfce.desktop")))
10568 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10569 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10570 [#:theme @var{%default-slim-theme}] @
10571 [#:theme-name @var{%default-slim-theme-name}]
10572 Return a service that spawns the SLiM graphical login manager, which in
10573 turn starts the X display server with @var{startx}, a command as returned by
10574 @code{xorg-start-command}.
10578 SLiM automatically looks for session types described by the @file{.desktop}
10579 files in @file{/run/current-system/profile/share/xsessions} and allows users
10580 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10581 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10582 adding them to the system-wide set of packages automatically makes them
10583 available at the log-in screen.
10585 In addition, @file{~/.xsession} files are honored. When available,
10586 @file{~/.xsession} must be an executable that starts a window manager
10587 and/or other X clients.
10589 When @var{allow-empty-passwords?} is true, allow logins with an empty
10590 password. When @var{auto-login?} is true, log in automatically as
10591 @var{default-user}.
10593 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10594 @var{theme} must be a gexp denoting the name of a directory containing the
10595 theme to use. In that case, @var{theme-name} specifies the name of the
10599 @defvr {Scheme Variable} %default-theme
10600 @defvrx {Scheme Variable} %default-theme-name
10601 The G-Expression denoting the default SLiM theme and its name.
10604 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10605 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10606 Return a derivation that builds a @var{guile} script to start the X server
10607 from @var{xorg-server}. @var{configuration-file} is the server configuration
10608 file or a derivation that builds it; when omitted, the result of
10609 @code{xorg-configuration-file} is used.
10611 Usually the X server is started by a login manager.
10614 @deffn {Scheme Procedure} xorg-configuration-file @
10615 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10616 Return a configuration file for the Xorg server containing search paths for
10617 all the common drivers.
10619 @var{drivers} must be either the empty list, in which case Xorg chooses a
10620 graphics driver automatically, or a list of driver names that will be tried in
10621 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10623 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10624 appropriate screen resolution; otherwise, it must be a list of
10625 resolutions---e.g., @code{((1024 768) (640 480))}.
10627 Last, @var{extra-config} is a list of strings or objects appended to the
10628 @code{text-file*} argument list. It is used to pass extra text to be added
10629 verbatim to the configuration file.
10632 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10633 Add @var{package}, a package for a screen-locker or screen-saver whose
10634 command is @var{program}, to the set of setuid programs and add a PAM entry
10635 for it. For example:
10638 (screen-locker-service xlockmore "xlock")
10641 makes the good ol' XlockMore usable.
10645 @node Printing Services
10646 @subsubsection Printing Services
10648 @cindex printer support with CUPS
10649 The @code{(gnu services cups)} module provides a Guix service definition
10650 for the CUPS printing service. To add printer support to a GuixSD
10651 system, add a @code{cups-service} to the operating system definition:
10653 @deffn {Scheme Variable} cups-service-type
10654 The service type for the CUPS print server. Its value should be a valid
10655 CUPS configuration (see below). To use the default settings, simply
10658 (service cups-service-type)
10662 The CUPS configuration controls the basic things about your CUPS
10663 installation: what interfaces it listens on, what to do if a print job
10664 fails, how much logging to do, and so on. To actually add a printer,
10665 you have to visit the @url{http://localhost:631} URL, or use a tool such
10666 as GNOME's printer configuration services. By default, configuring a
10667 CUPS service will generate a self-signed certificate if needed, for
10668 secure connections to the print server.
10670 Suppose you want to enable the Web interface of CUPS and also add
10671 support for HP printers @i{via} the @code{hplip} package. You can do
10672 that directly, like this (you need to use the @code{(gnu packages cups)}
10676 (service cups-service-type
10677 (cups-configuration
10678 (web-interface? #t)
10680 (list cups-filters hplip))))
10683 The available configuration parameters follow. Each parameter
10684 definition is preceded by its type; for example, @samp{string-list foo}
10685 indicates that the @code{foo} parameter should be specified as a list of
10686 strings. There is also a way to specify the configuration as a string,
10687 if you have an old @code{cupsd.conf} file that you want to port over
10688 from some other system; see the end for more details.
10690 @c The following documentation was initially generated by
10691 @c (generate-documentation) in (gnu services cups). Manually maintained
10692 @c documentation is better, so we shouldn't hesitate to edit below as
10693 @c needed. However if the change you want to make to this documentation
10694 @c can be done in an automated way, it's probably easier to change
10695 @c (generate-documentation) than to make it below and have to deal with
10696 @c the churn as CUPS updates.
10699 Available @code{cups-configuration} fields are:
10701 @deftypevr {@code{cups-configuration} parameter} package cups
10705 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10706 Drivers and other extensions to the CUPS package.
10709 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10710 Configuration of where to write logs, what directories to use for print
10711 spools, and related privileged configuration parameters.
10713 Available @code{files-configuration} fields are:
10715 @deftypevr {@code{files-configuration} parameter} log-location access-log
10716 Defines the access log filename. Specifying a blank filename disables
10717 access log generation. The value @code{stderr} causes log entries to be
10718 sent to the standard error file when the scheduler is running in the
10719 foreground, or to the system log daemon when run in the background. The
10720 value @code{syslog} causes log entries to be sent to the system log
10721 daemon. The server name may be included in filenames using the string
10722 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10724 Defaults to @samp{"/var/log/cups/access_log"}.
10727 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10728 Where CUPS should cache data.
10730 Defaults to @samp{"/var/cache/cups"}.
10733 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10734 Specifies the permissions for all configuration files that the scheduler
10737 Note that the permissions for the printers.conf file are currently
10738 masked to only allow access from the scheduler user (typically root).
10739 This is done because printer device URIs sometimes contain sensitive
10740 authentication information that should not be generally known on the
10741 system. There is no way to disable this security feature.
10743 Defaults to @samp{"0640"}.
10746 @deftypevr {@code{files-configuration} parameter} log-location error-log
10747 Defines the error log filename. Specifying a blank filename disables
10748 access log generation. The value @code{stderr} causes log entries to be
10749 sent to the standard error file when the scheduler is running in the
10750 foreground, or to the system log daemon when run in the background. The
10751 value @code{syslog} causes log entries to be sent to the system log
10752 daemon. The server name may be included in filenames using the string
10753 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10755 Defaults to @samp{"/var/log/cups/error_log"}.
10758 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10759 Specifies which errors are fatal, causing the scheduler to exit. The
10764 No errors are fatal.
10767 All of the errors below are fatal.
10770 Browsing initialization errors are fatal, for example failed connections
10771 to the DNS-SD daemon.
10774 Configuration file syntax errors are fatal.
10777 Listen or Port errors are fatal, except for IPv6 failures on the
10778 loopback or @code{any} addresses.
10781 Log file creation or write errors are fatal.
10784 Bad startup file permissions are fatal, for example shared TLS
10785 certificate and key files with world-read permissions.
10788 Defaults to @samp{"all -browse"}.
10791 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10792 Specifies whether the file pseudo-device can be used for new printer
10793 queues. The URI @uref{file:///dev/null} is always allowed.
10795 Defaults to @samp{#f}.
10798 @deftypevr {@code{files-configuration} parameter} string group
10799 Specifies the group name or ID that will be used when executing external
10802 Defaults to @samp{"lp"}.
10805 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10806 Specifies the permissions for all log files that the scheduler writes.
10808 Defaults to @samp{"0644"}.
10811 @deftypevr {@code{files-configuration} parameter} log-location page-log
10812 Defines the page log filename. Specifying a blank filename disables
10813 access log generation. The value @code{stderr} causes log entries to be
10814 sent to the standard error file when the scheduler is running in the
10815 foreground, or to the system log daemon when run in the background. The
10816 value @code{syslog} causes log entries to be sent to the system log
10817 daemon. The server name may be included in filenames using the string
10818 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10820 Defaults to @samp{"/var/log/cups/page_log"}.
10823 @deftypevr {@code{files-configuration} parameter} string remote-root
10824 Specifies the username that is associated with unauthenticated accesses
10825 by clients claiming to be the root user. The default is @code{remroot}.
10827 Defaults to @samp{"remroot"}.
10830 @deftypevr {@code{files-configuration} parameter} file-name request-root
10831 Specifies the directory that contains print jobs and other HTTP request
10834 Defaults to @samp{"/var/spool/cups"}.
10837 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10838 Specifies the level of security sandboxing that is applied to print
10839 filters, backends, and other child processes of the scheduler; either
10840 @code{relaxed} or @code{strict}. This directive is currently only
10841 used/supported on macOS.
10843 Defaults to @samp{strict}.
10846 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10847 Specifies the location of TLS certificates and private keys. CUPS will
10848 look for public and private keys in this directory: a @code{.crt} files
10849 for PEM-encoded certificates and corresponding @code{.key} files for
10850 PEM-encoded private keys.
10852 Defaults to @samp{"/etc/cups/ssl"}.
10855 @deftypevr {@code{files-configuration} parameter} file-name server-root
10856 Specifies the directory containing the server configuration files.
10858 Defaults to @samp{"/etc/cups"}.
10861 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10862 Specifies whether the scheduler calls fsync(2) after writing
10863 configuration or state files.
10865 Defaults to @samp{#f}.
10868 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10869 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10872 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10873 Specifies the directory where temporary files are stored.
10875 Defaults to @samp{"/var/spool/cups/tmp"}.
10878 @deftypevr {@code{files-configuration} parameter} string user
10879 Specifies the user name or ID that is used when running external
10882 Defaults to @samp{"lp"}.
10886 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10887 Specifies the logging level for the AccessLog file. The @code{config}
10888 level logs when printers and classes are added, deleted, or modified and
10889 when configuration files are accessed or updated. The @code{actions}
10890 level logs when print jobs are submitted, held, released, modified, or
10891 canceled, and any of the conditions for @code{config}. The @code{all}
10892 level logs all requests.
10894 Defaults to @samp{actions}.
10897 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10898 Specifies whether to purge job history data automatically when it is no
10899 longer required for quotas.
10901 Defaults to @samp{#f}.
10904 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10905 Specifies which protocols to use for local printer sharing.
10907 Defaults to @samp{dnssd}.
10910 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10911 Specifies whether the CUPS web interface is advertised.
10913 Defaults to @samp{#f}.
10916 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10917 Specifies whether shared printers are advertised.
10919 Defaults to @samp{#f}.
10922 @deftypevr {@code{cups-configuration} parameter} string classification
10923 Specifies the security classification of the server. Any valid banner
10924 name can be used, including "classified", "confidential", "secret",
10925 "topsecret", and "unclassified", or the banner can be omitted to disable
10926 secure printing functions.
10928 Defaults to @samp{""}.
10931 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
10932 Specifies whether users may override the classification (cover page) of
10933 individual print jobs using the @code{job-sheets} option.
10935 Defaults to @samp{#f}.
10938 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
10939 Specifies the default type of authentication to use.
10941 Defaults to @samp{Basic}.
10944 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
10945 Specifies whether encryption will be used for authenticated requests.
10947 Defaults to @samp{Required}.
10950 @deftypevr {@code{cups-configuration} parameter} string default-language
10951 Specifies the default language to use for text and web content.
10953 Defaults to @samp{"en"}.
10956 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
10957 Specifies the default paper size for new print queues. @samp{"Auto"}
10958 uses a locale-specific default, while @samp{"None"} specifies there is
10959 no default paper size. Specific size names are typically
10960 @samp{"Letter"} or @samp{"A4"}.
10962 Defaults to @samp{"Auto"}.
10965 @deftypevr {@code{cups-configuration} parameter} string default-policy
10966 Specifies the default access policy to use.
10968 Defaults to @samp{"default"}.
10971 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
10972 Specifies whether local printers are shared by default.
10974 Defaults to @samp{#t}.
10977 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
10978 Specifies the delay for updating of configuration and state files, in
10979 seconds. A value of 0 causes the update to happen as soon as possible,
10980 typically within a few milliseconds.
10982 Defaults to @samp{30}.
10985 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
10986 Specifies what to do when an error occurs. Possible values are
10987 @code{abort-job}, which will discard the failed print job;
10988 @code{retry-job}, which will retry the job at a later time;
10989 @code{retry-this-job}, which retries the failed job immediately; and
10990 @code{stop-printer}, which stops the printer.
10992 Defaults to @samp{stop-printer}.
10995 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
10996 Specifies the maximum cost of filters that are run concurrently, which
10997 can be used to minimize disk, memory, and CPU resource problems. A
10998 limit of 0 disables filter limiting. An average print to a
10999 non-PostScript printer needs a filter limit of about 200. A PostScript
11000 printer needs about half that (100). Setting the limit below these
11001 thresholds will effectively limit the scheduler to printing a single job
11004 Defaults to @samp{0}.
11007 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
11008 Specifies the scheduling priority of filters that are run to print a
11009 job. The nice value ranges from 0, the highest priority, to 19, the
11012 Defaults to @samp{0}.
11015 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
11016 Specifies whether to do reverse lookups on connecting clients. The
11017 @code{double} setting causes @code{cupsd} to verify that the hostname
11018 resolved from the address matches one of the addresses returned for that
11019 hostname. Double lookups also prevent clients with unregistered
11020 addresses from connecting to your server. Only set this option to
11021 @code{#t} or @code{double} if absolutely required.
11023 Defaults to @samp{#f}.
11026 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
11027 Specifies the number of seconds to wait before killing the filters and
11028 backend associated with a canceled or held job.
11030 Defaults to @samp{30}.
11033 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
11034 Specifies the interval between retries of jobs in seconds. This is
11035 typically used for fax queues but can also be used with normal print
11036 queues whose error policy is @code{retry-job} or
11037 @code{retry-current-job}.
11039 Defaults to @samp{30}.
11042 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
11043 Specifies the number of retries that are done for jobs. This is
11044 typically used for fax queues but can also be used with normal print
11045 queues whose error policy is @code{retry-job} or
11046 @code{retry-current-job}.
11048 Defaults to @samp{5}.
11051 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
11052 Specifies whether to support HTTP keep-alive connections.
11054 Defaults to @samp{#t}.
11057 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
11058 Specifies how long an idle client connection remains open, in seconds.
11060 Defaults to @samp{30}.
11063 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
11064 Specifies the maximum size of print files, IPP requests, and HTML form
11065 data. A limit of 0 disables the limit check.
11067 Defaults to @samp{0}.
11070 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
11071 Listens on the specified interfaces for connections. Valid values are
11072 of the form @var{address}:@var{port}, where @var{address} is either an
11073 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
11074 indicate all addresses. Values can also be file names of local UNIX
11075 domain sockets. The Listen directive is similar to the Port directive
11076 but allows you to restrict access to specific interfaces or networks.
11079 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
11080 Specifies the number of pending connections that will be allowed. This
11081 normally only affects very busy servers that have reached the MaxClients
11082 limit, but can also be triggered by large numbers of simultaneous
11083 connections. When the limit is reached, the operating system will
11084 refuse additional connections until the scheduler can accept the pending
11087 Defaults to @samp{128}.
11090 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
11091 Specifies a set of additional access controls.
11093 Available @code{location-access-controls} fields are:
11095 @deftypevr {@code{location-access-controls} parameter} file-name path
11096 Specifies the URI path to which the access control applies.
11099 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
11100 Access controls for all access to this path, in the same format as the
11101 @code{access-controls} of @code{operation-access-control}.
11103 Defaults to @samp{()}.
11106 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
11107 Access controls for method-specific access to this path.
11109 Defaults to @samp{()}.
11111 Available @code{method-access-controls} fields are:
11113 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
11114 If @code{#t}, apply access controls to all methods except the listed
11115 methods. Otherwise apply to only the listed methods.
11117 Defaults to @samp{#f}.
11120 @deftypevr {@code{method-access-controls} parameter} method-list methods
11121 Methods to which this access control applies.
11123 Defaults to @samp{()}.
11126 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
11127 Access control directives, as a list of strings. Each string should be
11128 one directive, such as "Order allow,deny".
11130 Defaults to @samp{()}.
11135 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
11136 Specifies the number of debugging messages that are retained for logging
11137 if an error occurs in a print job. Debug messages are logged regardless
11138 of the LogLevel setting.
11140 Defaults to @samp{100}.
11143 @deftypevr {@code{cups-configuration} parameter} log-level log-level
11144 Specifies the level of logging for the ErrorLog file. The value
11145 @code{none} stops all logging while @code{debug2} logs everything.
11147 Defaults to @samp{info}.
11150 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
11151 Specifies the format of the date and time in the log files. The value
11152 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
11154 Defaults to @samp{standard}.
11157 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
11158 Specifies the maximum number of simultaneous clients that are allowed by
11161 Defaults to @samp{100}.
11164 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
11165 Specifies the maximum number of simultaneous clients that are allowed
11166 from a single address.
11168 Defaults to @samp{100}.
11171 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
11172 Specifies the maximum number of copies that a user can print of each
11175 Defaults to @samp{9999}.
11178 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
11179 Specifies the maximum time a job may remain in the @code{indefinite}
11180 hold state before it is canceled. A value of 0 disables cancellation of
11183 Defaults to @samp{0}.
11186 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
11187 Specifies the maximum number of simultaneous jobs that are allowed. Set
11188 to 0 to allow an unlimited number of jobs.
11190 Defaults to @samp{500}.
11193 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
11194 Specifies the maximum number of simultaneous jobs that are allowed per
11195 printer. A value of 0 allows up to MaxJobs jobs per printer.
11197 Defaults to @samp{0}.
11200 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
11201 Specifies the maximum number of simultaneous jobs that are allowed per
11202 user. A value of 0 allows up to MaxJobs jobs per user.
11204 Defaults to @samp{0}.
11207 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
11208 Specifies the maximum time a job may take to print before it is
11209 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
11211 Defaults to @samp{10800}.
11214 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
11215 Specifies the maximum size of the log files before they are rotated, in
11216 bytes. The value 0 disables log rotation.
11218 Defaults to @samp{1048576}.
11221 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
11222 Specifies the maximum amount of time to allow between files in a
11223 multiple file print job, in seconds.
11225 Defaults to @samp{300}.
11228 @deftypevr {@code{cups-configuration} parameter} string page-log-format
11229 Specifies the format of PageLog lines. Sequences beginning with percent
11230 (@samp{%}) characters are replaced with the corresponding information,
11231 while all other characters are copied literally. The following percent
11232 sequences are recognized:
11236 insert a single percent character
11239 insert the value of the specified IPP attribute
11242 insert the number of copies for the current page
11245 insert the current page number
11248 insert the current date and time in common log format
11254 insert the printer name
11257 insert the username
11260 A value of the empty string disables page logging. The string @code{%p
11261 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
11262 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
11265 Defaults to @samp{""}.
11268 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
11269 Passes the specified environment variable(s) to child processes; a list
11272 Defaults to @samp{()}.
11275 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
11276 Specifies named access control policies.
11278 Available @code{policy-configuration} fields are:
11280 @deftypevr {@code{policy-configuration} parameter} string name
11281 Name of the policy.
11284 @deftypevr {@code{policy-configuration} parameter} string job-private-access
11285 Specifies an access list for a job's private values. @code{@@ACL} maps
11286 to the printer's requesting-user-name-allowed or
11287 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11288 owner. @code{@@SYSTEM} maps to the groups listed for the
11289 @code{system-group} field of the @code{files-config} configuration,
11290 which is reified into the @code{cups-files.conf(5)} file. Other
11291 possible elements of the access list include specific user names, and
11292 @code{@@@var{group}} to indicate members of a specific group. The
11293 access list may also be simply @code{all} or @code{default}.
11295 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11298 @deftypevr {@code{policy-configuration} parameter} string job-private-values
11299 Specifies the list of job values to make private, or @code{all},
11300 @code{default}, or @code{none}.
11302 Defaults to @samp{"job-name job-originating-host-name
11303 job-originating-user-name phone"}.
11306 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
11307 Specifies an access list for a subscription's private values.
11308 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
11309 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11310 owner. @code{@@SYSTEM} maps to the groups listed for the
11311 @code{system-group} field of the @code{files-config} configuration,
11312 which is reified into the @code{cups-files.conf(5)} file. Other
11313 possible elements of the access list include specific user names, and
11314 @code{@@@var{group}} to indicate members of a specific group. The
11315 access list may also be simply @code{all} or @code{default}.
11317 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11320 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
11321 Specifies the list of job values to make private, or @code{all},
11322 @code{default}, or @code{none}.
11324 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
11325 notify-subscriber-user-name notify-user-data"}.
11328 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
11329 Access control by IPP operation.
11331 Defaults to @samp{()}.
11335 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
11336 Specifies whether job files (documents) are preserved after a job is
11337 printed. If a numeric value is specified, job files are preserved for
11338 the indicated number of seconds after printing. Otherwise a boolean
11339 value applies indefinitely.
11341 Defaults to @samp{86400}.
11344 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
11345 Specifies whether the job history is preserved after a job is printed.
11346 If a numeric value is specified, the job history is preserved for the
11347 indicated number of seconds after printing. If @code{#t}, the job
11348 history is preserved until the MaxJobs limit is reached.
11350 Defaults to @samp{#t}.
11353 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
11354 Specifies the amount of time to wait for job completion before
11355 restarting the scheduler.
11357 Defaults to @samp{30}.
11360 @deftypevr {@code{cups-configuration} parameter} string rip-cache
11361 Specifies the maximum amount of memory to use when converting documents
11362 into bitmaps for a printer.
11364 Defaults to @samp{"128m"}.
11367 @deftypevr {@code{cups-configuration} parameter} string server-admin
11368 Specifies the email address of the server administrator.
11370 Defaults to @samp{"root@@localhost.localdomain"}.
11373 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
11374 The ServerAlias directive is used for HTTP Host header validation when
11375 clients connect to the scheduler from external interfaces. Using the
11376 special name @code{*} can expose your system to known browser-based DNS
11377 rebinding attacks, even when accessing sites through a firewall. If the
11378 auto-discovery of alternate names does not work, we recommend listing
11379 each alternate name with a ServerAlias directive instead of using
11382 Defaults to @samp{*}.
11385 @deftypevr {@code{cups-configuration} parameter} string server-name
11386 Specifies the fully-qualified host name of the server.
11388 Defaults to @samp{"localhost"}.
11391 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
11392 Specifies what information is included in the Server header of HTTP
11393 responses. @code{None} disables the Server header. @code{ProductOnly}
11394 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
11395 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
11396 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
11397 the output of the @code{uname} command. @code{Full} reports @code{CUPS
11398 2.0.0 (@var{uname}) IPP/2.0}.
11400 Defaults to @samp{Minimal}.
11403 @deftypevr {@code{cups-configuration} parameter} string set-env
11404 Set the specified environment variable to be passed to child processes.
11406 Defaults to @samp{"variable value"}.
11409 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
11410 Listens on the specified interfaces for encrypted connections. Valid
11411 values are of the form @var{address}:@var{port}, where @var{address} is
11412 either an IPv6 address enclosed in brackets, an IPv4 address, or
11413 @code{*} to indicate all addresses.
11415 Defaults to @samp{()}.
11418 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
11419 Sets encryption options. By default, CUPS only supports encryption
11420 using TLS v1.0 or higher using known secure cipher suites. The
11421 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
11422 required for some older clients that do not implement newer ones. The
11423 @code{AllowSSL3} option enables SSL v3.0, which is required for some
11424 older clients that do not support TLS v1.0.
11426 Defaults to @samp{()}.
11429 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
11430 Specifies whether the scheduler requires clients to strictly adhere to
11431 the IPP specifications.
11433 Defaults to @samp{#f}.
11436 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
11437 Specifies the HTTP request timeout, in seconds.
11439 Defaults to @samp{300}.
11443 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
11444 Specifies whether the web interface is enabled.
11446 Defaults to @samp{#f}.
11449 At this point you're probably thinking ``oh dear, Guix manual, I like
11450 you but you can stop already with the configuration options''. Indeed.
11451 However, one more point: it could be that you have an existing
11452 @code{cupsd.conf} that you want to use. In that case, you can pass an
11453 @code{opaque-cups-configuration} as the configuration of a
11454 @code{cups-service-type}.
11456 Available @code{opaque-cups-configuration} fields are:
11458 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
11462 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
11463 The contents of the @code{cupsd.conf}, as a string.
11466 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
11467 The contents of the @code{cups-files.conf} file, as a string.
11470 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
11471 strings of the same name, you could instantiate a CUPS service like
11475 (service cups-service-type
11476 (opaque-cups-configuration
11477 (cupsd.conf cupsd.conf)
11478 (cups-files.conf cups-files.conf)))
11482 @node Desktop Services
11483 @subsubsection Desktop Services
11485 The @code{(gnu services desktop)} module provides services that are
11486 usually useful in the context of a ``desktop'' setup---that is, on a
11487 machine running a graphical display server, possibly with graphical user
11488 interfaces, etc. It also defines services that provide specific desktop
11489 environments like GNOME and XFCE.
11491 To simplify things, the module defines a variable containing the set of
11492 services that users typically expect on a machine with a graphical
11493 environment and networking:
11495 @defvr {Scheme Variable} %desktop-services
11496 This is a list of services that builds upon @var{%base-services} and
11497 adds or adjusts services for a typical ``desktop'' setup.
11499 In particular, it adds a graphical login manager (@pxref{X Window,
11500 @code{slim-service}}), screen lockers,
11501 a network management tool (@pxref{Networking
11502 Services, @code{wicd-service}}), energy and color management services,
11503 the @code{elogind} login and seat manager, the Polkit privilege service,
11504 the GeoClue location service, an NTP client (@pxref{Networking
11505 Services}), the Avahi daemon, and has the name service switch service
11506 configured to be able to use @code{nss-mdns} (@pxref{Name Service
11510 The @var{%desktop-services} variable can be used as the @code{services}
11511 field of an @code{operating-system} declaration (@pxref{operating-system
11512 Reference, @code{services}}).
11514 Additionally, the @code{gnome-desktop-service} and
11515 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11516 system. To ``add GNOME'' means that system-level services like the
11517 backlight adjustment helpers and the power management utilities are
11518 added to the system, extending @code{polkit} and @code{dbus}
11519 appropriately, allowing GNOME to operate with elevated privileges on a
11520 limited number of special-purpose system interfaces. Additionally,
11521 adding a service made by @code{gnome-desktop-service} adds the GNOME
11522 metapackage to the system profile. Likewise, adding the XFCE service
11523 not only adds the @code{xfce} metapackage to the system profile, but it
11524 also gives the Thunar file manager the ability to open a ``root-mode''
11525 file management window, if the user authenticates using the
11526 administrator's password via the standard polkit graphical interface.
11528 @deffn {Scheme Procedure} gnome-desktop-service
11529 Return a service that adds the @code{gnome} package to the system
11530 profile, and extends polkit with the actions from
11531 @code{gnome-settings-daemon}.
11534 @deffn {Scheme Procedure} xfce-desktop-service
11535 Return a service that adds the @code{xfce} package to the system profile,
11536 and extends polkit with the ability for @code{thunar} to manipulate the
11537 file system as root from within a user session, after the user has
11538 authenticated with the administrator's password.
11541 Because the GNOME and XFCE desktop services pull in so many packages,
11542 the default @code{%desktop-services} variable doesn't include either of
11543 them by default. To add GNOME or XFCE, just @code{cons} them onto
11544 @code{%desktop-services} in the @code{services} field of your
11545 @code{operating-system}:
11548 (use-modules (gnu))
11549 (use-service-modules desktop)
11552 ;; cons* adds items to the list given as its last argument.
11553 (services (cons* (gnome-desktop-service)
11554 (xfce-desktop-service)
11555 %desktop-services))
11559 These desktop environments will then be available as options in the
11560 graphical login window.
11562 The actual service definitions included in @code{%desktop-services} and
11563 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
11564 are described below.
11566 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
11567 Return a service that runs the ``system bus'', using @var{dbus}, with
11568 support for @var{services}.
11570 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11571 facility. Its system bus is used to allow system services to communicate
11572 and to be notified of system-wide events.
11574 @var{services} must be a list of packages that provide an
11575 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11576 and policy files. For example, to allow avahi-daemon to use the system bus,
11577 @var{services} must be equal to @code{(list avahi)}.
11580 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11581 Return a service that runs the @code{elogind} login and
11582 seat management daemon. @uref{https://github.com/andywingo/elogind,
11583 Elogind} exposes a D-Bus interface that can be used to know which users
11584 are logged in, know what kind of sessions they have open, suspend the
11585 system, inhibit system suspend, reboot the system, and other tasks.
11587 Elogind handles most system-level power events for a computer, for
11588 example suspending the system when a lid is closed, or shutting it down
11589 when the power button is pressed.
11591 The @var{config} keyword argument specifies the configuration for
11592 elogind, and should be the result of an @code{(elogind-configuration
11593 (@var{parameter} @var{value})...)} invocation. Available parameters and
11594 their default values are:
11597 @item kill-user-processes?
11599 @item kill-only-users
11601 @item kill-exclude-users
11603 @item inhibit-delay-max-seconds
11605 @item handle-power-key
11607 @item handle-suspend-key
11609 @item handle-hibernate-key
11611 @item handle-lid-switch
11613 @item handle-lid-switch-docked
11615 @item power-key-ignore-inhibited?
11617 @item suspend-key-ignore-inhibited?
11619 @item hibernate-key-ignore-inhibited?
11621 @item lid-switch-ignore-inhibited?
11623 @item holdoff-timeout-seconds
11627 @item idle-action-seconds
11629 @item runtime-directory-size-percent
11631 @item runtime-directory-size
11635 @item suspend-state
11636 @code{("mem" "standby" "freeze")}
11639 @item hibernate-state
11641 @item hibernate-mode
11642 @code{("platform" "shutdown")}
11643 @item hybrid-sleep-state
11645 @item hybrid-sleep-mode
11646 @code{("suspend" "platform" "shutdown")}
11650 @deffn {Scheme Procedure} polkit-service @
11651 [#:polkit @var{polkit}]
11652 Return a service that runs the
11653 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11654 management service}, which allows system administrators to grant access to
11655 privileged operations in a structured way. By querying the Polkit service, a
11656 privileged system component can know when it should grant additional
11657 capabilities to ordinary users. For example, an ordinary user can be granted
11658 the capability to suspend the system if the user is logged in locally.
11661 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11662 [#:watts-up-pro? #f] @
11663 [#:poll-batteries? #t] @
11664 [#:ignore-lid? #f] @
11665 [#:use-percentage-for-policy? #f] @
11666 [#:percentage-low 10] @
11667 [#:percentage-critical 3] @
11668 [#:percentage-action 2] @
11669 [#:time-low 1200] @
11670 [#:time-critical 300] @
11671 [#:time-action 120] @
11672 [#:critical-power-action 'hybrid-sleep]
11673 Return a service that runs @uref{http://upower.freedesktop.org/,
11674 @command{upowerd}}, a system-wide monitor for power consumption and battery
11675 levels, with the given configuration settings. It implements the
11676 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11680 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11681 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11682 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11683 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11684 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11687 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11688 Return a service that runs @command{colord}, a system service with a D-Bus
11689 interface to manage the color profiles of input and output devices such as
11690 screens and scanners. It is notably used by the GNOME Color Manager graphical
11691 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11692 site} for more information.
11695 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11696 Return a configuration allowing an application to access GeoClue
11697 location data. @var{name} is the Desktop ID of the application, without
11698 the @code{.desktop} part. If @var{allowed?} is true, the application
11699 will have access to location information by default. The boolean
11700 @var{system?} value indicates whether an application is a system component
11701 or not. Finally @var{users} is a list of UIDs of all users for which
11702 this application is allowed location info access. An empty users list
11703 means that all users are allowed.
11706 @defvr {Scheme Variable} %standard-geoclue-applications
11707 The standard list of well-known GeoClue application configurations,
11708 granting authority to the GNOME date-and-time utility to ask for the
11709 current location in order to set the time zone, and allowing the
11710 IceCat and Epiphany web browsers to request location information.
11711 IceCat and Epiphany both query the user before allowing a web page to
11712 know the user's location.
11715 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11716 [#:whitelist '()] @
11717 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11718 [#:submit-data? #f]
11719 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11720 [#:submission-nick "geoclue"] @
11721 [#:applications %standard-geoclue-applications]
11722 Return a service that runs the GeoClue location service. This service
11723 provides a D-Bus interface to allow applications to request access to a
11724 user's physical location, and optionally to add information to online
11725 location databases. See
11726 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11727 web site} for more information.
11730 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
11731 Return a service that runs the @command{bluetoothd} daemon, which manages
11732 all the Bluetooth devices and provides a number of D-Bus interfaces.
11734 Users need to be in the @code{lp} group to access the D-Bus service.
11737 @node Database Services
11738 @subsubsection Database Services
11742 The @code{(gnu services databases)} module provides the following services.
11744 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11745 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11746 [#:port 5432] [#:locale ``en_US.utf8'']
11747 Return a service that runs @var{postgresql}, the PostgreSQL database
11750 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11751 creates a database cluster with @var{locale} as the default
11752 locale, stored in @var{data-directory}. It then listens on @var{port}.
11755 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11756 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11759 The optional @var{config} argument specifies the configuration for
11760 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11763 @deftp {Data Type} mysql-configuration
11764 Data type representing the configuration of @var{mysql-service}.
11767 @item @code{mysql} (default: @var{mariadb})
11768 Package object of the MySQL database server, can be either @var{mariadb}
11771 For MySQL, a temporary root password will be displayed at activation time.
11772 For MariaDB, the root password is empty.
11774 @item @code{port} (default: @code{3306})
11775 TCP port on which the database server listens for incoming connections.
11779 @defvr {Scheme Variable} memcached-service-type
11780 This is the service type for the @uref{https://memcached.org/,
11781 Memcached} service, which provides a distributed in memory cache. The
11782 value for the service type is a @code{memcached-configuration} object.
11786 (service memcached-service-type)
11789 @deftp {Data Type} memcached-configuration
11790 Data type representing the configuration of memcached.
11793 @item @code{memcached} (default: @code{memcached})
11794 The Memcached package to use.
11796 @item @code{interfaces} (default: @code{'("0.0.0.0")})
11797 Network interfaces on which to listen.
11799 @item @code{tcp-port} (default: @code{11211})
11800 Port on which to accept connections on,
11802 @item @code{udp-port} (default: @code{11211})
11803 Port on which to accept UDP connections on, a value of 0 will disable
11804 listening on a UDP socket.
11806 @item @code{additional-options} (default: @code{'()})
11807 Additional command line options to pass to @code{memcached}.
11811 @defvr {Scheme Variable} redis-service-type
11812 This is the service type for the @uref{https://redis.io/, Redis}
11813 key/value store, whose value is a @code{redis-configuration} object.
11816 @deftp {Data Type} redis-configuration
11817 Data type representing the configuration of redis.
11820 @item @code{redis} (default: @code{redis})
11821 The Redis package to use.
11823 @item @code{bind} (default: @code{"127.0.0.1"})
11824 Network interface on which to listen.
11826 @item @code{port} (default: @code{6379})
11827 Port on which to accept connections on, a value of 0 will disable
11828 listening on a TCP socket.
11830 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11831 Directory in which to store the database and related files.
11835 @node Mail Services
11836 @subsubsection Mail Services
11840 The @code{(gnu services mail)} module provides Guix service definitions
11841 for email services: IMAP, POP3, and LMTP servers, as well as mail
11842 transport agents (MTAs). Lots of acronyms! These services are detailed
11843 in the subsections below.
11845 @subsubheading Dovecot Service
11847 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11848 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11851 By default, Dovecot does not need much configuration; the default
11852 configuration object created by @code{(dovecot-configuration)} will
11853 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11854 certificate will be generated for TLS-protected connections, though
11855 Dovecot will also listen on cleartext ports by default. There are a
11856 number of options, though, which mail administrators might need to change,
11857 and as is the case with other services, Guix allows the system
11858 administrator to specify these parameters via a uniform Scheme interface.
11860 For example, to specify that mail is located at @code{maildir~/.mail},
11861 one would instantiate the Dovecot service like this:
11864 (dovecot-service #:config
11865 (dovecot-configuration
11866 (mail-location "maildir:~/.mail")))
11869 The available configuration parameters follow. Each parameter
11870 definition is preceded by its type; for example, @samp{string-list foo}
11871 indicates that the @code{foo} parameter should be specified as a list of
11872 strings. There is also a way to specify the configuration as a string,
11873 if you have an old @code{dovecot.conf} file that you want to port over
11874 from some other system; see the end for more details.
11876 @c The following documentation was initially generated by
11877 @c (generate-documentation) in (gnu services mail). Manually maintained
11878 @c documentation is better, so we shouldn't hesitate to edit below as
11879 @c needed. However if the change you want to make to this documentation
11880 @c can be done in an automated way, it's probably easier to change
11881 @c (generate-documentation) than to make it below and have to deal with
11882 @c the churn as dovecot updates.
11884 Available @code{dovecot-configuration} fields are:
11886 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11887 The dovecot package.
11890 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11891 A list of IPs or hosts where to listen for connections. @samp{*}
11892 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11893 interfaces. If you want to specify non-default ports or anything more
11894 complex, customize the address and port fields of the
11895 @samp{inet-listener} of the specific services you are interested in.
11898 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11899 List of protocols we want to serve. Available protocols include
11900 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11902 Available @code{protocol-configuration} fields are:
11904 @deftypevr {@code{protocol-configuration} parameter} string name
11905 The name of the protocol.
11908 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
11909 UNIX socket path to the master authentication server to find users.
11910 This is used by imap (for shared users) and lda.
11911 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11914 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
11915 Space separated list of plugins to load.
11918 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
11919 Maximum number of IMAP connections allowed for a user from each IP
11920 address. NOTE: The username is compared case-sensitively.
11921 Defaults to @samp{10}.
11926 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
11927 List of services to enable. Available services include @samp{imap},
11928 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
11931 Available @code{service-configuration} fields are:
11933 @deftypevr {@code{service-configuration} parameter} string kind
11934 The service kind. Valid values include @code{director},
11935 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
11936 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
11937 @code{tcpwrap}, @code{quota-warning}, or anything else.
11940 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
11941 Listeners for the service. A listener is either a
11942 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
11943 an @code{inet-listener-configuration}.
11944 Defaults to @samp{()}.
11946 Available @code{unix-listener-configuration} fields are:
11948 @deftypevr {@code{unix-listener-configuration} parameter} string path
11949 Path to the file, relative to @code{base-dir} field. This is also used as
11953 @deftypevr {@code{unix-listener-configuration} parameter} string mode
11954 The access mode for the socket.
11955 Defaults to @samp{"0600"}.
11958 @deftypevr {@code{unix-listener-configuration} parameter} string user
11959 The user to own the socket.
11960 Defaults to @samp{""}.
11963 @deftypevr {@code{unix-listener-configuration} parameter} string group
11964 The group to own the socket.
11965 Defaults to @samp{""}.
11969 Available @code{fifo-listener-configuration} fields are:
11971 @deftypevr {@code{fifo-listener-configuration} parameter} string path
11972 Path to the file, relative to @code{base-dir} field. This is also used as
11976 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
11977 The access mode for the socket.
11978 Defaults to @samp{"0600"}.
11981 @deftypevr {@code{fifo-listener-configuration} parameter} string user
11982 The user to own the socket.
11983 Defaults to @samp{""}.
11986 @deftypevr {@code{fifo-listener-configuration} parameter} string group
11987 The group to own the socket.
11988 Defaults to @samp{""}.
11992 Available @code{inet-listener-configuration} fields are:
11994 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
11995 The protocol to listen for.
11998 @deftypevr {@code{inet-listener-configuration} parameter} string address
11999 The address on which to listen, or empty for all addresses.
12000 Defaults to @samp{""}.
12003 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
12004 The port on which to listen.
12007 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
12008 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
12010 Defaults to @samp{#t}.
12015 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
12016 Number of connections to handle before starting a new process.
12017 Typically the only useful values are 0 (unlimited) or 1. 1 is more
12018 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
12019 Defaults to @samp{1}.
12022 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
12023 Number of processes to always keep waiting for more connections.
12024 Defaults to @samp{0}.
12027 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
12028 If you set @samp{service-count 0}, you probably need to grow
12030 Defaults to @samp{256000000}.
12035 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
12036 Dict configuration, as created by the @code{dict-configuration}
12039 Available @code{dict-configuration} fields are:
12041 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
12042 A list of key-value pairs that this dict should hold.
12043 Defaults to @samp{()}.
12048 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
12049 A list of passdb configurations, each one created by the
12050 @code{passdb-configuration} constructor.
12052 Available @code{passdb-configuration} fields are:
12054 @deftypevr {@code{passdb-configuration} parameter} string driver
12055 The driver that the passdb should use. Valid values include
12056 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
12058 Defaults to @samp{"pam"}.
12061 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
12062 Space separated list of arguments to the passdb driver.
12063 Defaults to @samp{""}.
12068 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
12069 List of userdb configurations, each one created by the
12070 @code{userdb-configuration} constructor.
12072 Available @code{userdb-configuration} fields are:
12074 @deftypevr {@code{userdb-configuration} parameter} string driver
12075 The driver that the userdb should use. Valid values include
12076 @samp{passwd} and @samp{static}.
12077 Defaults to @samp{"passwd"}.
12080 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
12081 Space separated list of arguments to the userdb driver.
12082 Defaults to @samp{""}.
12085 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
12086 Override fields from passwd.
12087 Defaults to @samp{()}.
12092 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
12093 Plug-in configuration, created by the @code{plugin-configuration}
12097 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
12098 List of namespaces. Each item in the list is created by the
12099 @code{namespace-configuration} constructor.
12101 Available @code{namespace-configuration} fields are:
12103 @deftypevr {@code{namespace-configuration} parameter} string name
12104 Name for this namespace.
12107 @deftypevr {@code{namespace-configuration} parameter} string type
12108 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
12109 Defaults to @samp{"private"}.
12112 @deftypevr {@code{namespace-configuration} parameter} string separator
12113 Hierarchy separator to use. You should use the same separator for
12114 all namespaces or some clients get confused. @samp{/} is usually a good
12115 one. The default however depends on the underlying mail storage
12117 Defaults to @samp{""}.
12120 @deftypevr {@code{namespace-configuration} parameter} string prefix
12121 Prefix required to access this namespace. This needs to be
12122 different for all namespaces. For example @samp{Public/}.
12123 Defaults to @samp{""}.
12126 @deftypevr {@code{namespace-configuration} parameter} string location
12127 Physical location of the mailbox. This is in the same format as
12128 mail_location, which is also the default for it.
12129 Defaults to @samp{""}.
12132 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
12133 There can be only one INBOX, and this setting defines which
12135 Defaults to @samp{#f}.
12138 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
12139 If namespace is hidden, it's not advertised to clients via NAMESPACE
12140 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
12141 useful when converting from another server with different namespaces
12142 which you want to deprecate but still keep working. For example you can
12143 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
12145 Defaults to @samp{#f}.
12148 @deftypevr {@code{namespace-configuration} parameter} boolean list?
12149 Show the mailboxes under this namespace with the LIST command. This
12150 makes the namespace visible for clients that do not support the NAMESPACE
12151 extension. The special @code{children} value lists child mailboxes, but
12152 hides the namespace prefix.
12153 Defaults to @samp{#t}.
12156 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
12157 Namespace handles its own subscriptions. If set to @code{#f}, the
12158 parent namespace handles them. The empty prefix should always have this
12160 Defaults to @samp{#t}.
12163 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
12164 List of predefined mailboxes in this namespace.
12165 Defaults to @samp{()}.
12167 Available @code{mailbox-configuration} fields are:
12169 @deftypevr {@code{mailbox-configuration} parameter} string name
12170 Name for this mailbox.
12173 @deftypevr {@code{mailbox-configuration} parameter} string auto
12174 @samp{create} will automatically create this mailbox.
12175 @samp{subscribe} will both create and subscribe to the mailbox.
12176 Defaults to @samp{"no"}.
12179 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
12180 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
12181 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
12182 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
12183 Defaults to @samp{()}.
12190 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
12191 Base directory where to store runtime data.
12192 Defaults to @samp{"/var/run/dovecot/"}.
12195 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
12196 Greeting message for clients.
12197 Defaults to @samp{"Dovecot ready."}.
12200 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
12201 List of trusted network ranges. Connections from these IPs are
12202 allowed to override their IP addresses and ports (for logging and for
12203 authentication checks). @samp{disable-plaintext-auth} is also ignored
12204 for these networks. Typically you would specify your IMAP proxy servers
12206 Defaults to @samp{()}.
12209 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
12210 List of login access check sockets (e.g. tcpwrap).
12211 Defaults to @samp{()}.
12214 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
12215 Show more verbose process titles (in ps). Currently shows user name
12216 and IP address. Useful for seeing who is actually using the IMAP
12217 processes (e.g. shared mailboxes or if the same uid is used for multiple
12219 Defaults to @samp{#f}.
12222 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
12223 Should all processes be killed when Dovecot master process shuts down.
12224 Setting this to @code{#f} means that Dovecot can be upgraded without
12225 forcing existing client connections to close (although that could also
12226 be a problem if the upgrade is e.g. due to a security fix).
12227 Defaults to @samp{#t}.
12230 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
12231 If non-zero, run mail commands via this many connections to doveadm
12232 server, instead of running them directly in the same process.
12233 Defaults to @samp{0}.
12236 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
12237 UNIX socket or host:port used for connecting to doveadm server.
12238 Defaults to @samp{"doveadm-server"}.
12241 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
12242 List of environment variables that are preserved on Dovecot startup
12243 and passed down to all of its child processes. You can also give
12244 key=value pairs to always set specific settings.
12247 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
12248 Disable LOGIN command and all other plaintext authentications unless
12249 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
12250 matches the local IP (i.e. you're connecting from the same computer),
12251 the connection is considered secure and plaintext authentication is
12252 allowed. See also ssl=required setting.
12253 Defaults to @samp{#t}.
12256 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
12257 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
12258 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
12259 for caching to be used.
12260 Defaults to @samp{0}.
12263 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
12264 Time to live for cached data. After TTL expires the cached record
12265 is no longer used, *except* if the main database lookup returns internal
12266 failure. We also try to handle password changes automatically: If
12267 user's previous authentication was successful, but this one wasn't, the
12268 cache isn't used. For now this works only with plaintext
12270 Defaults to @samp{"1 hour"}.
12273 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
12274 TTL for negative hits (user not found, password mismatch).
12275 0 disables caching them completely.
12276 Defaults to @samp{"1 hour"}.
12279 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
12280 List of realms for SASL authentication mechanisms that need them.
12281 You can leave it empty if you don't want to support multiple realms.
12282 Many clients simply use the first one listed here, so keep the default
12284 Defaults to @samp{()}.
12287 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
12288 Default realm/domain to use if none was specified. This is used for
12289 both SASL realms and appending @@domain to username in plaintext
12291 Defaults to @samp{""}.
12294 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
12295 List of allowed characters in username. If the user-given username
12296 contains a character not listed in here, the login automatically fails.
12297 This is just an extra check to make sure user can't exploit any
12298 potential quote escaping vulnerabilities with SQL/LDAP databases. If
12299 you want to allow all characters, set this value to empty.
12300 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
12303 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
12304 Username character translations before it's looked up from
12305 databases. The value contains series of from -> to characters. For
12306 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
12307 translated to @samp{@@}.
12308 Defaults to @samp{""}.
12311 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
12312 Username formatting before it's looked up from databases. You can
12313 use the standard variables here, e.g. %Lu would lowercase the username,
12314 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
12315 change the @samp{@@} into @samp{-AT-}. This translation is done after
12316 @samp{auth-username-translation} changes.
12317 Defaults to @samp{"%Lu"}.
12320 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
12321 If you want to allow master users to log in by specifying the master
12322 username within the normal username string (i.e. not using SASL
12323 mechanism's support for it), you can specify the separator character
12324 here. The format is then <username><separator><master username>.
12325 UW-IMAP uses @samp{*} as the separator, so that could be a good
12327 Defaults to @samp{""}.
12330 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
12331 Username to use for users logging in with ANONYMOUS SASL
12333 Defaults to @samp{"anonymous"}.
12336 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
12337 Maximum number of dovecot-auth worker processes. They're used to
12338 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
12339 They're automatically created and destroyed as needed.
12340 Defaults to @samp{30}.
12343 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
12344 Host name to use in GSSAPI principal names. The default is to use
12345 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
12346 allow all keytab entries.
12347 Defaults to @samp{""}.
12350 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
12351 Kerberos keytab to use for the GSSAPI mechanism. Will use the
12352 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
12353 need to change the auth service to run as root to be able to read this
12355 Defaults to @samp{""}.
12358 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
12359 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
12360 and @samp{ntlm-auth} helper.
12361 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
12362 Defaults to @samp{#f}.
12365 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
12366 Path for Samba's @samp{ntlm-auth} helper binary.
12367 Defaults to @samp{"/usr/bin/ntlm_auth"}.
12370 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
12371 Time to delay before replying to failed authentications.
12372 Defaults to @samp{"2 secs"}.
12375 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
12376 Require a valid SSL client certificate or the authentication
12378 Defaults to @samp{#f}.
12381 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
12382 Take the username from client's SSL certificate, using
12383 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
12385 Defaults to @samp{#f}.
12388 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
12389 List of wanted authentication mechanisms. Supported mechanisms are:
12390 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
12391 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
12392 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
12393 @samp{disable-plaintext-auth} setting.
12396 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
12397 List of IPs or hostnames to all director servers, including ourself.
12398 Ports can be specified as ip:port. The default port is the same as what
12399 director service's @samp{inet-listener} is using.
12400 Defaults to @samp{()}.
12403 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
12404 List of IPs or hostnames to all backend mail servers. Ranges are
12405 allowed too, like 10.0.0.10-10.0.0.30.
12406 Defaults to @samp{()}.
12409 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
12410 How long to redirect users to a specific server after it no longer
12411 has any connections.
12412 Defaults to @samp{"15 min"}.
12415 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
12416 TCP/IP port that accepts doveadm connections (instead of director
12417 connections) If you enable this, you'll also need to add
12418 @samp{inet-listener} for the port.
12419 Defaults to @samp{0}.
12422 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
12423 How the username is translated before being hashed. Useful values
12424 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
12425 are shared within domain.
12426 Defaults to @samp{"%Lu"}.
12429 @deftypevr {@code{dovecot-configuration} parameter} string log-path
12430 Log file to use for error messages. @samp{syslog} logs to syslog,
12431 @samp{/dev/stderr} logs to stderr.
12432 Defaults to @samp{"syslog"}.
12435 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
12436 Log file to use for informational messages. Defaults to
12438 Defaults to @samp{""}.
12441 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
12442 Log file to use for debug messages. Defaults to
12443 @samp{info-log-path}.
12444 Defaults to @samp{""}.
12447 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
12448 Syslog facility to use if you're logging to syslog. Usually if you
12449 don't want to use @samp{mail}, you'll use local0..local7. Also other
12450 standard facilities are supported.
12451 Defaults to @samp{"mail"}.
12454 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
12455 Log unsuccessful authentication attempts and the reasons why they
12457 Defaults to @samp{#f}.
12460 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
12461 In case of password mismatches, log the attempted password. Valid
12462 values are no, plain and sha1. sha1 can be useful for detecting brute
12463 force password attempts vs. user simply trying the same password over
12464 and over again. You can also truncate the value to n chars by appending
12465 ":n" (e.g. sha1:6).
12466 Defaults to @samp{#f}.
12469 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
12470 Even more verbose logging for debugging purposes. Shows for example
12472 Defaults to @samp{#f}.
12475 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
12476 In case of password mismatches, log the passwords and used scheme so
12477 the problem can be debugged. Enabling this also enables
12479 Defaults to @samp{#f}.
12482 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
12483 Enable mail process debugging. This can help you figure out why
12484 Dovecot isn't finding your mails.
12485 Defaults to @samp{#f}.
12488 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
12489 Show protocol level SSL errors.
12490 Defaults to @samp{#f}.
12493 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
12494 Prefix for each line written to log file. % codes are in
12495 strftime(3) format.
12496 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
12499 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
12500 List of elements we want to log. The elements which have a
12501 non-empty variable value are joined together to form a comma-separated
12505 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
12506 Login log format. %s contains @samp{login-log-format-elements}
12507 string, %$ contains the data we want to log.
12508 Defaults to @samp{"%$: %s"}.
12511 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
12512 Log prefix for mail processes. See doc/wiki/Variables.txt for list
12513 of possible variables you can use.
12514 Defaults to @samp{"\"%s(%u): \""}.
12517 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
12518 Format to use for logging mail deliveries. You can use variables:
12521 Delivery status message (e.g. @samp{saved to INBOX})
12533 Defaults to @samp{"msgid=%m: %$"}.
12536 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
12537 Location for users' mailboxes. The default is empty, which means
12538 that Dovecot tries to find the mailboxes automatically. This won't work
12539 if the user doesn't yet have any mail, so you should explicitly tell
12540 Dovecot the full location.
12542 If you're using mbox, giving a path to the INBOX
12543 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
12544 where the other mailboxes are kept. This is called the "root mail
12545 directory", and it must be the first path given in the
12546 @samp{mail-location} setting.
12548 There are a few special variables you can use, eg.:
12554 user part in user@@domain, same as %u if there's no domain
12556 domain part in user@@domain, empty if there's no domain
12561 See doc/wiki/Variables.txt for full list. Some examples:
12563 @item maildir:~/Maildir
12564 @item mbox:~/mail:INBOX=/var/mail/%u
12565 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
12567 Defaults to @samp{""}.
12570 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
12571 System user and group used to access mails. If you use multiple,
12572 userdb can override these by returning uid or gid fields. You can use
12573 either numbers or names. <doc/wiki/UserIds.txt>.
12574 Defaults to @samp{""}.
12577 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
12579 Defaults to @samp{""}.
12582 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
12583 Group to enable temporarily for privileged operations. Currently
12584 this is used only with INBOX when either its initial creation or
12585 dotlocking fails. Typically this is set to "mail" to give access to
12587 Defaults to @samp{""}.
12590 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
12591 Grant access to these supplementary groups for mail processes.
12592 Typically these are used to set up access to shared mailboxes. Note
12593 that it may be dangerous to set these if users can create
12594 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
12595 could allow a user to delete others' mailboxes, or ln -s
12596 /secret/shared/box ~/mail/mybox would allow reading it).
12597 Defaults to @samp{""}.
12600 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12601 Allow full file system access to clients. There's no access checks
12602 other than what the operating system does for the active UID/GID. It
12603 works with both maildir and mboxes, allowing you to prefix mailboxes
12604 names with e.g. /path/ or ~user/.
12605 Defaults to @samp{#f}.
12608 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12609 Don't use mmap() at all. This is required if you store indexes to
12610 shared file systems (NFS or clustered file system).
12611 Defaults to @samp{#f}.
12614 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12615 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12616 supports @samp{O_EXCL} since version 3, so this should be safe to use
12617 nowadays by default.
12618 Defaults to @samp{#t}.
12621 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12622 When to use fsync() or fdatasync() calls:
12625 Whenever necessary to avoid losing important data
12627 Useful with e.g. NFS when write()s are delayed
12629 Never use it (best performance, but crashes can lose data).
12631 Defaults to @samp{"optimized"}.
12634 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12635 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12636 NFS caches whenever needed. If you're using only a single mail server
12638 Defaults to @samp{#f}.
12641 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12642 Mail index files also exist in NFS. Setting this to yes requires
12643 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12644 Defaults to @samp{#f}.
12647 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12648 Locking method for index files. Alternatives are fcntl, flock and
12649 dotlock. Dotlocking uses some tricks which may create more disk I/O
12650 than other locking methods. NFS users: flock doesn't work, remember to
12651 change @samp{mmap-disable}.
12652 Defaults to @samp{"fcntl"}.
12655 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12656 Directory in which LDA/LMTP temporarily stores incoming mails >128
12658 Defaults to @samp{"/tmp"}.
12661 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12662 Valid UID range for users. This is mostly to make sure that users can't
12663 log in as daemons or other system users. Note that denying root logins is
12664 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12666 Defaults to @samp{500}.
12669 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12671 Defaults to @samp{0}.
12674 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12675 Valid GID range for users. Users having non-valid GID as primary group ID
12676 aren't allowed to log in. If user belongs to supplementary groups with
12677 non-valid GIDs, those groups are not set.
12678 Defaults to @samp{1}.
12681 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12683 Defaults to @samp{0}.
12686 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12687 Maximum allowed length for mail keyword name. It's only forced when
12688 trying to create new keywords.
12689 Defaults to @samp{50}.
12692 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12693 List of directories under which chrooting is allowed for mail
12694 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12695 too). This setting doesn't affect @samp{login-chroot}
12696 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12697 "/./" in home dirs are ignored. WARNING: Never add directories here
12698 which local users can modify, that may lead to root exploit. Usually
12699 this should be done only if you don't allow shell access for users.
12700 <doc/wiki/Chrooting.txt>.
12701 Defaults to @samp{()}.
12704 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12705 Default chroot directory for mail processes. This can be overridden
12706 for specific users in user database by giving /./ in user's home
12707 directory (e.g. /home/./user chroots into /home). Note that usually
12708 there is no real need to do chrooting, Dovecot doesn't allow users to
12709 access files outside their mail directory anyway. If your home
12710 directories are prefixed with the chroot directory, append "/." to
12711 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12712 Defaults to @samp{""}.
12715 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12716 UNIX socket path to master authentication server to find users.
12717 This is used by imap (for shared users) and lda.
12718 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12721 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12722 Directory where to look up mail plugins.
12723 Defaults to @samp{"/usr/lib/dovecot"}.
12726 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12727 List of plugins to load for all services. Plugins specific to IMAP,
12728 LDA, etc. are added to this list in their own .conf files.
12729 Defaults to @samp{()}.
12732 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12733 The minimum number of mails in a mailbox before updates are done to
12734 cache file. This allows optimizing Dovecot's behavior to do less disk
12735 writes at the cost of more disk reads.
12736 Defaults to @samp{0}.
12739 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12740 When IDLE command is running, mailbox is checked once in a while to
12741 see if there are any new mails or other changes. This setting defines
12742 the minimum time to wait between those checks. Dovecot can also use
12743 dnotify, inotify and kqueue to find out immediately when changes
12745 Defaults to @samp{"30 secs"}.
12748 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12749 Save mails with CR+LF instead of plain LF. This makes sending those
12750 mails take less CPU, especially with sendfile() syscall with Linux and
12751 FreeBSD. But it also creates a bit more disk I/O which may just make it
12752 slower. Also note that if other software reads the mboxes/maildirs,
12753 they may handle the extra CRs wrong and cause problems.
12754 Defaults to @samp{#f}.
12757 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12758 By default LIST command returns all entries in maildir beginning
12759 with a dot. Enabling this option makes Dovecot return only entries
12760 which are directories. This is done by stat()ing each entry, so it
12761 causes more disk I/O.
12762 (For systems setting struct @samp{dirent->d_type} this check is free
12763 and it's done always regardless of this setting).
12764 Defaults to @samp{#f}.
12767 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12768 When copying a message, do it with hard links whenever possible.
12769 This makes the performance much better, and it's unlikely to have any
12771 Defaults to @samp{#t}.
12774 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12775 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12776 directory only when its mtime changes unexpectedly or when we can't find
12777 the mail otherwise.
12778 Defaults to @samp{#f}.
12781 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12782 Which locking methods to use for locking mbox. There are four
12787 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12788 solution. If you want to use /var/mail/ like directory, the users will
12789 need write access to that directory.
12791 Same as dotlock, but if it fails because of permissions or because there
12792 isn't enough disk space, just skip it.
12794 Use this if possible. Works with NFS too if lockd is used.
12796 May not exist in all systems. Doesn't work with NFS.
12798 May not exist in all systems. Doesn't work with NFS.
12801 You can use multiple locking methods; if you do the order they're declared
12802 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12803 locking methods as well. Some operating systems don't allow using some of
12804 them simultaneously.
12807 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12811 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12812 Maximum time to wait for lock (all of them) before aborting.
12813 Defaults to @samp{"5 mins"}.
12816 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12817 If dotlock exists but the mailbox isn't modified in any way,
12818 override the lock file after this much time.
12819 Defaults to @samp{"2 mins"}.
12822 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12823 When mbox changes unexpectedly we have to fully read it to find out
12824 what changed. If the mbox is large this can take a long time. Since
12825 the change is usually just a newly appended mail, it'd be faster to
12826 simply read the new mails. If this setting is enabled, Dovecot does
12827 this but still safely fallbacks to re-reading the whole mbox file
12828 whenever something in mbox isn't how it's expected to be. The only real
12829 downside to this setting is that if some other MUA changes message
12830 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12831 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12832 Defaults to @samp{#t}.
12835 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12836 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12837 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12838 @samp{mbox-dirty-syncs} is ignored.
12839 Defaults to @samp{#f}.
12842 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12843 Delay writing mbox headers until doing a full write sync (EXPUNGE
12844 and CHECK commands and when closing the mailbox). This is especially
12845 useful for POP3 where clients often delete all mails. The downside is
12846 that our changes aren't immediately visible to other MUAs.
12847 Defaults to @samp{#t}.
12850 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12851 If mbox size is smaller than this (e.g. 100k), don't write index
12852 files. If an index file already exists it's still read, just not
12854 Defaults to @samp{0}.
12857 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12858 Maximum dbox file size until it's rotated.
12859 Defaults to @samp{2000000}.
12862 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12863 Maximum dbox file age until it's rotated. Typically in days. Day
12864 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12866 Defaults to @samp{"1d"}.
12869 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12870 When creating new mdbox files, immediately preallocate their size to
12871 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12872 with some file systems (ext4, xfs).
12873 Defaults to @samp{#f}.
12876 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12877 sdbox and mdbox support saving mail attachments to external files,
12878 which also allows single instance storage for them. Other backends
12879 don't support this for now.
12881 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12883 Directory root where to store mail attachments. Disabled, if empty.
12884 Defaults to @samp{""}.
12887 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12888 Attachments smaller than this aren't saved externally. It's also
12889 possible to write a plugin to disable saving specific attachments
12891 Defaults to @samp{128000}.
12894 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12895 File system backend to use for saving attachments:
12898 No SiS done by Dovecot (but this might help FS's own deduplication)
12900 SiS with immediate byte-by-byte comparison during saving
12901 @item sis-queue posix
12902 SiS with delayed comparison and deduplication.
12904 Defaults to @samp{"sis posix"}.
12907 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
12908 Hash format to use in attachment filenames. You can add any text and
12909 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
12910 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
12911 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
12912 Defaults to @samp{"%@{sha1@}"}.
12915 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
12917 Defaults to @samp{100}.
12920 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
12922 Defaults to @samp{1000}.
12925 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
12926 Default VSZ (virtual memory size) limit for service processes.
12927 This is mainly intended to catch and kill processes that leak memory
12928 before they eat up everything.
12929 Defaults to @samp{256000000}.
12932 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
12933 Login user is internally used by login processes. This is the most
12934 untrusted user in Dovecot system. It shouldn't have access to anything
12936 Defaults to @samp{"dovenull"}.
12939 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
12940 Internal user is used by unprivileged processes. It should be
12941 separate from login user, so that login processes can't disturb other
12943 Defaults to @samp{"dovecot"}.
12946 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
12947 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
12948 Defaults to @samp{"required"}.
12951 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
12952 PEM encoded X.509 SSL/TLS certificate (public key).
12953 Defaults to @samp{"</etc/dovecot/default.pem"}.
12956 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
12957 PEM encoded SSL/TLS private key. The key is opened before
12958 dropping root privileges, so keep the key file unreadable by anyone but
12960 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
12963 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
12964 If key file is password protected, give the password here.
12965 Alternatively give it when starting dovecot with -p parameter. Since
12966 this file is often world-readable, you may want to place this setting
12967 instead to a different.
12968 Defaults to @samp{""}.
12971 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
12972 PEM encoded trusted certificate authority. Set this only if you
12973 intend to use @samp{ssl-verify-client-cert? #t}. The file should
12974 contain the CA certificate(s) followed by the matching
12975 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
12976 Defaults to @samp{""}.
12979 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
12980 Require that CRL check succeeds for client certificates.
12981 Defaults to @samp{#t}.
12984 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
12985 Request client to send a certificate. If you also want to require
12986 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
12987 Defaults to @samp{#f}.
12990 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
12991 Which field from certificate to use for username. commonName and
12992 x500UniqueIdentifier are the usual choices. You'll also need to set
12993 @samp{auth-ssl-username-from-cert? #t}.
12994 Defaults to @samp{"commonName"}.
12997 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
12998 How often to regenerate the SSL parameters file. Generation is
12999 quite CPU intensive operation. The value is in hours, 0 disables
13000 regeneration entirely.
13001 Defaults to @samp{168}.
13004 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
13005 SSL protocols to use.
13006 Defaults to @samp{"!SSLv2"}.
13009 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
13010 SSL ciphers to use.
13011 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
13014 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
13015 SSL crypto device to use, for valid values run "openssl engine".
13016 Defaults to @samp{""}.
13019 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
13020 Address to use when sending rejection mails.
13021 %d expands to recipient domain.
13022 Defaults to @samp{"postmaster@@%d"}.
13025 @deftypevr {@code{dovecot-configuration} parameter} string hostname
13026 Hostname to use in various parts of sent mails (e.g. in Message-Id)
13027 and in LMTP replies. Default is the system's real hostname@@domain.
13028 Defaults to @samp{""}.
13031 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
13032 If user is over quota, return with temporary failure instead of
13034 Defaults to @samp{#f}.
13037 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
13038 Binary to use for sending mails.
13039 Defaults to @samp{"/usr/sbin/sendmail"}.
13042 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
13043 If non-empty, send mails via this SMTP host[:port] instead of
13045 Defaults to @samp{""}.
13048 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
13049 Subject: header to use for rejection mails. You can use the same
13050 variables as for @samp{rejection-reason} below.
13051 Defaults to @samp{"Rejected: %s"}.
13054 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
13055 Human readable error message for rejection mails. You can use
13068 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
13071 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
13072 Delimiter character between local-part and detail in email
13074 Defaults to @samp{"+"}.
13077 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
13078 Header where the original recipient address (SMTP's RCPT TO:
13079 address) is taken from if not available elsewhere. With dovecot-lda -a
13080 parameter overrides this. A commonly used header for this is
13082 Defaults to @samp{""}.
13085 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
13086 Should saving a mail to a nonexistent mailbox automatically create
13088 Defaults to @samp{#f}.
13091 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
13092 Should automatically created mailboxes be also automatically
13094 Defaults to @samp{#f}.
13097 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
13098 Maximum IMAP command line length. Some clients generate very long
13099 command lines with huge mailboxes, so you may need to raise this if you
13100 get "Too long argument" or "IMAP command line too large" errors
13102 Defaults to @samp{64000}.
13105 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
13106 IMAP logout format string:
13109 total number of bytes read from client
13111 total number of bytes sent to client.
13113 Defaults to @samp{"in=%i out=%o"}.
13116 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
13117 Override the IMAP CAPABILITY response. If the value begins with '+',
13118 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
13119 Defaults to @samp{""}.
13122 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
13123 How long to wait between "OK Still here" notifications when client
13125 Defaults to @samp{"2 mins"}.
13128 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
13129 ID field names and values to send to clients. Using * as the value
13130 makes Dovecot use the default value. The following fields have default
13131 values currently: name, version, os, os-version, support-url,
13133 Defaults to @samp{""}.
13136 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
13137 ID fields sent by client to log. * means everything.
13138 Defaults to @samp{""}.
13141 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
13142 Workarounds for various client bugs:
13145 @item delay-newmail
13146 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
13147 CHECK commands. Some clients ignore them otherwise, for example OSX
13148 Mail (<v2.1). Outlook Express breaks more badly though, without this it
13149 may show user "Message no longer in server" errors. Note that OE6
13150 still breaks even with this workaround if synchronization is set to
13153 @item tb-extra-mailbox-sep
13154 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
13155 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
13156 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
13158 @item tb-lsub-flags
13159 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
13160 This makes Thunderbird realize they aren't selectable and show them
13161 greyed out, instead of only later giving "not selectable" popup error.
13163 Defaults to @samp{()}.
13166 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
13167 Host allowed in URLAUTH URLs sent by client. "*" allows all.
13168 Defaults to @samp{""}.
13172 Whew! Lots of configuration options. The nice thing about it though is
13173 that GuixSD has a complete interface to Dovecot's configuration
13174 language. This allows not only a nice way to declare configurations,
13175 but also offers reflective capabilities as well: users can write code to
13176 inspect and transform configurations from within Scheme.
13178 However, it could be that you just want to get a @code{dovecot.conf} up
13179 and running. In that case, you can pass an
13180 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
13181 @code{dovecot-service}. As its name indicates, an opaque configuration
13182 does not have easy reflective capabilities.
13184 Available @code{opaque-dovecot-configuration} fields are:
13186 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
13187 The dovecot package.
13190 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
13191 The contents of the @code{dovecot.conf}, as a string.
13194 For example, if your @code{dovecot.conf} is just the empty string, you
13195 could instantiate a dovecot service like this:
13198 (dovecot-service #:config
13199 (opaque-dovecot-configuration
13203 @subsubheading OpenSMTPD Service
13205 @deffn {Scheme Variable} opensmtpd-service-type
13206 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
13207 service, whose value should be an @code{opensmtpd-configuration} object
13208 as in this example:
13211 (service opensmtpd-service-type
13212 (opensmtpd-configuration
13213 (config-file (local-file "./my-smtpd.conf"))))
13217 @deftp {Data Type} opensmtpd-configuration
13218 Data type representing the configuration of opensmtpd.
13221 @item @code{package} (default: @var{opensmtpd})
13222 Package object of the OpenSMTPD SMTP server.
13224 @item @code{config-file} (default: @var{%default-opensmtpd-file})
13225 File-like object of the OpenSMTPD configuration file to use. By default
13226 it listens on the loopback network interface, and allows for mail from
13227 users and daemons on the local machine, as well as permitting email to
13228 remote servers. Run @command{man smtpd.conf} for more information.
13233 @subsubheading Exim Service
13235 @cindex mail transfer agent (MTA)
13236 @cindex MTA (mail transfer agent)
13239 @deffn {Scheme Variable} exim-service-type
13240 This is the type of the @uref{https://exim.org, Exim} mail transfer
13241 agent (MTA), whose value should be an @code{exim-configuration} object
13242 as in this example:
13245 (service exim-service-type
13246 (exim-configuration
13247 (config-file (local-file "./my-exim.conf"))))
13251 In order to use an @code{exim-service-type} service you must also have a
13252 @code{mail-aliases-service-type} service present in your
13253 @code{operating-system} (even if it has no aliases).
13255 @deftp {Data Type} exim-configuration
13256 Data type representing the configuration of exim.
13259 @item @code{package} (default: @var{exim})
13260 Package object of the Exim server.
13262 @item @code{config-file} (default: @code{#f})
13263 File-like object of the Exim configuration file to use. If its value is
13264 @code{#f} then use the default configuration file from the package
13265 provided in @code{package}. The resulting configuration file is loaded
13266 after setting the @code{exim_user} and @code{exim_group} configuration
13272 @subsubheading Mail Aliases Service
13274 @cindex email aliases
13275 @cindex aliases, for email addresses
13277 @deffn {Scheme Variable} mail-aliases-service-type
13278 This is the type of the service which provides @code{/etc/aliases},
13279 specifying how to deliver mail to users on this system.
13282 (service mail-aliases-service-type
13283 '(("postmaster" "bob")
13284 ("bob" "bob@@example.com" "bob@@example2.com")))
13288 The configuration for a @code{mail-aliases-service-type} service is an
13289 association list denoting how to deliver mail that comes to this
13290 system. Each entry is of the form @code{(alias addresses ...)}, with
13291 @code{alias} specifying the local alias and @code{addresses} specifying
13292 where to deliver this user's mail.
13294 The aliases aren't required to exist as users on the local system. In
13295 the above example, there doesn't need to be a @code{postmaster} entry in
13296 the @code{operating-system}'s @code{user-accounts} in order to deliver
13297 the @code{postmaster} mail to @code{bob} (which subsequently would
13298 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
13300 @node Messaging Services
13301 @subsubsection Messaging Services
13306 The @code{(gnu services messaging)} module provides Guix service
13307 definitions for messaging services: currently only Prosody is supported.
13309 @subsubheading Prosody Service
13311 @deffn {Scheme Variable} prosody-service-type
13312 This is the type for the @uref{http://prosody.im, Prosody XMPP
13313 communication server}. Its value must be a @code{prosody-configuration}
13314 record as in this example:
13317 (service prosody-service-type
13318 (prosody-configuration
13319 (modules-enabled (cons "groups" %default-modules-enabled))
13322 (int-component-configuration
13323 (hostname "conference.example.net")
13325 (mod-muc (mod-muc-configuration)))))
13328 (virtualhost-configuration
13329 (domain "example.net"))))))
13332 See below for details about @code{prosody-configuration}.
13336 By default, Prosody does not need much configuration. Only one
13337 @code{virtualhosts} field is needed: it specifies the domain you wish
13340 Prosodyctl will help you generate X.509 certificates and keys:
13343 prosodyctl cert request example.net
13346 The available configuration parameters follow. Each parameter
13347 definition is preceded by its type; for example, @samp{string-list foo}
13348 indicates that the @code{foo} parameter should be specified as a list of
13349 strings. Types starting with @code{maybe-} denote parameters that won't
13350 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
13352 There is also a way to specify the configuration as a string, if you
13353 have an old @code{prosody.cfg.lua} file that you want to port over from
13354 some other system; see the end for more details.
13356 @c The following documentation was initially generated by
13357 @c (generate-documentation) in (gnu services messaging). Manually maintained
13358 @c documentation is better, so we shouldn't hesitate to edit below as
13359 @c needed. However if the change you want to make to this documentation
13360 @c can be done in an automated way, it's probably easier to change
13361 @c (generate-documentation) than to make it below and have to deal with
13362 @c the churn as Prosody updates.
13364 Available @code{prosody-configuration} fields are:
13366 @deftypevr {@code{prosody-configuration} parameter} package prosody
13367 The Prosody package.
13370 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
13371 Location of the Prosody data storage directory. See
13372 @url{http://prosody.im/doc/configure}.
13373 Defaults to @samp{"/var/lib/prosody"}.
13376 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
13377 Additional plugin directories. They are searched in all the specified
13378 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
13379 Defaults to @samp{()}.
13382 @deftypevr {@code{prosody-configuration} parameter} string-list admins
13383 This is a list of accounts that are admins for the server. Note that you
13384 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
13385 @url{http://prosody.im/doc/creating_accounts}.
13386 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
13387 Defaults to @samp{()}.
13390 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
13391 Enable use of libevent for better performance under high load. See
13392 @url{http://prosody.im/doc/libevent}.
13393 Defaults to @samp{#f}.
13396 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
13397 This is the list of modules Prosody will load on startup. It looks for
13398 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
13399 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
13400 Defaults to @samp{%default-modules-enabled}.
13403 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
13404 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
13405 should you want to disable them then add them to this list.
13406 Defaults to @samp{()}.
13409 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
13410 Path to a text file where the shared groups are defined. If this path is
13411 empty then @samp{mod_groups} does nothing. See
13412 @url{http://prosody.im/doc/modules/mod_groups}.
13413 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
13416 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
13417 Disable account creation by default, for security. See
13418 @url{http://prosody.im/doc/creating_accounts}.
13419 Defaults to @samp{#f}.
13422 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
13423 These are the SSL/TLS-related settings. Most of them are disabled so to
13424 use Prosody's defaults. If you do not completely understand these options, do
13425 not add them to your config, it is easy to lower the security of your server
13426 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
13428 Available @code{ssl-configuration} fields are:
13430 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
13431 This determines what handshake to use.
13434 @deftypevr {@code{ssl-configuration} parameter} file-name key
13435 Path to your private key file, relative to @code{/etc/prosody}.
13436 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
13439 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
13440 Path to your certificate file, relative to @code{/etc/prosody}.
13441 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
13444 @deftypevr {@code{ssl-configuration} parameter} file-name capath
13445 Path to directory containing root certificates that you wish Prosody to
13446 trust when verifying the certificates of remote servers.
13447 Defaults to @samp{"/etc/ssl/certs"}.
13450 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
13451 Path to a file containing root certificates that you wish Prosody to trust.
13452 Similar to @code{capath} but with all certificates concatenated together.
13455 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
13456 A list of verification options (these mostly map to OpenSSL's
13457 @code{set_verify()} flags).
13460 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
13461 A list of general options relating to SSL/TLS. These map to OpenSSL's
13462 @code{set_options()}. For a full list of options available in LuaSec, see the
13466 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
13467 How long a chain of certificate authorities to check when looking for a
13468 trusted root certificate.
13471 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
13472 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
13473 clients, and in what order.
13476 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
13477 A path to a file containing parameters for Diffie-Hellman key exchange. You
13478 can create such a file with:
13479 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
13482 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
13483 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
13484 @samp{"secp384r1"}.
13487 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
13488 A list of "extra" verification options.
13491 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
13492 Password for encrypted private keys.
13497 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
13498 Whether to force all client-to-server connections to be encrypted or not.
13499 See @url{http://prosody.im/doc/modules/mod_tls}.
13500 Defaults to @samp{#f}.
13503 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
13504 Whether to force all server-to-server connections to be encrypted or not.
13505 See @url{http://prosody.im/doc/modules/mod_tls}.
13506 Defaults to @samp{#f}.
13509 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
13510 Whether to require encryption and certificate authentication. This
13511 provides ideal security, but requires servers you communicate with to support
13512 encryption AND present valid, trusted certificates. See
13513 @url{http://prosody.im/doc/s2s#security}.
13514 Defaults to @samp{#f}.
13517 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
13518 Many servers don't support encryption or have invalid or self-signed
13519 certificates. You can list domains here that will not be required to
13520 authenticate using certificates. They will be authenticated using DNS. See
13521 @url{http://prosody.im/doc/s2s#security}.
13522 Defaults to @samp{()}.
13525 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
13526 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
13527 valid certificates for some domains by specifying a list here. See
13528 @url{http://prosody.im/doc/s2s#security}.
13529 Defaults to @samp{()}.
13532 @deftypevr {@code{prosody-configuration} parameter} string authentication
13533 Select the authentication backend to use. The default provider stores
13534 passwords in plaintext and uses Prosody's configured data storage to store the
13535 authentication data. If you do not trust your server please see
13536 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
13537 about using the hashed backend. See also
13538 @url{http://prosody.im/doc/authentication}
13539 Defaults to @samp{"internal_plain"}.
13542 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
13543 Set logging options. Advanced logging configuration is not yet supported
13544 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
13545 Defaults to @samp{"*syslog"}.
13548 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
13549 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
13550 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
13553 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
13554 A host in Prosody is a domain on which user accounts can be created. For
13555 example if you want your users to have addresses like
13556 @samp{"john.smith@@example.com"} then you need to add a host
13557 @samp{"example.com"}. All options in this list will apply only to this host.
13559 Note: the name "virtual" host is used in configuration to avoid confusion with
13560 the actual physical host that Prosody is installed on. A single Prosody
13561 instance can serve many domains, each one defined as a VirtualHost entry in
13562 Prosody's configuration. Conversely a server that hosts a single domain would
13563 have just one VirtualHost entry.
13565 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
13567 Available @code{virtualhost-configuration} fields are:
13569 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
13570 @deftypevr {@code{virtualhost-configuration} parameter} string domain
13571 Domain you wish Prosody to serve.
13576 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
13577 Components are extra services on a server which are available to clients,
13578 usually on a subdomain of the main server (such as
13579 @samp{"mycomponent.example.com"}). Example components might be chatroom
13580 servers, user directories, or gateways to other protocols.
13582 Internal components are implemented with Prosody-specific plugins. To add an
13583 internal component, you simply fill the hostname field, and the plugin you wish
13584 to use for the component.
13586 See @url{http://prosody.im/doc/components}.
13587 Defaults to @samp{()}.
13589 Available @code{int-component-configuration} fields are:
13591 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
13592 @deftypevr {@code{int-component-configuration} parameter} string hostname
13593 Hostname of the component.
13596 @deftypevr {@code{int-component-configuration} parameter} string plugin
13597 Plugin you wish to use for the component.
13600 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
13601 Multi-user chat (MUC) is Prosody's module for allowing you to create
13602 hosted chatrooms/conferences for XMPP users.
13604 General information on setting up and using multi-user chatrooms can be found
13605 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
13606 which you should read if you are new to XMPP chatrooms.
13608 See also @url{http://prosody.im/doc/modules/mod_muc}.
13610 Available @code{mod-muc-configuration} fields are:
13612 @deftypevr {@code{mod-muc-configuration} parameter} string name
13613 The name to return in service discovery responses.
13614 Defaults to @samp{"Prosody Chatrooms"}.
13617 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
13618 If @samp{#t}, this will only allow admins to create new chatrooms.
13619 Otherwise anyone can create a room. The value @samp{"local"} restricts room
13620 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
13621 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
13622 restricts to service administrators only.
13623 Defaults to @samp{#f}.
13626 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
13627 Maximum number of history messages that will be sent to the member that has
13628 just joined the room.
13629 Defaults to @samp{20}.
13636 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13637 External components use XEP-0114, which most standalone components
13638 support. To add an external component, you simply fill the hostname field. See
13639 @url{http://prosody.im/doc/components}.
13640 Defaults to @samp{()}.
13642 Available @code{ext-component-configuration} fields are:
13644 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
13645 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13646 Password which the component will use to log in.
13649 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13650 Hostname of the component.
13655 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13656 Port(s) Prosody listens on for component connections.
13659 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13660 Interface Prosody listens on for component connections.
13661 Defaults to @samp{"127.0.0.1"}.
13664 It could be that you just want to get a @code{prosody.cfg.lua}
13665 up and running. In that case, you can pass an
13666 @code{opaque-prosody-configuration} record as the value of
13667 @code{prosody-service-type}. As its name indicates, an opaque configuration
13668 does not have easy reflective capabilities.
13669 Available @code{opaque-prosody-configuration} fields are:
13671 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13672 The prosody package.
13675 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13676 The contents of the @code{prosody.cfg.lua} to use.
13679 For example, if your @code{prosody.cfg.lua} is just the empty
13680 string, you could instantiate a prosody service like this:
13683 (service prosody-service-type
13684 (opaque-prosody-configuration
13685 (prosody.cfg.lua "")))
13688 @node Monitoring Services
13689 @subsubsection Monitoring Services
13691 @subsubheading Tailon Service
13693 @uref{https://tailon.readthedocs.io/, Tailon} is a web application for
13694 viewing and searching log files.
13696 The following example will configure the service with default values.
13697 By default, Tailon can be accessed on port 8080 (@code{http://localhost:8080}).
13700 (service tailon-service-type)
13703 The following example customises more of the Tailon configuration,
13704 adding @command{sed} to the list of allowed commands.
13707 (service tailon-service-type
13708 (tailon-configuration
13710 (tailon-configuration-file
13711 (allowed-commands '("tail" "grep" "awk" "sed"))))))
13715 @deftp {Data Type} tailon-configuration
13716 Data type representing the configuration of Tailon.
13717 This type has the following parameters:
13720 @item @code{config-file} (default: @code{(tailon-configuration-file)})
13721 The configuration file to use for Tailon. This can be set to a
13722 @dfn{tailon-configuration-file} record value, or any gexp
13723 (@pxref{G-Expressions}).
13725 For example, to instead use a local file, the @code{local-file} function
13729 (service tailon-service-type
13730 (tailon-configuration
13731 (config-file (local-file "./my-tailon.conf"))))
13734 @item @code{package} (default: @code{tailon})
13735 The tailon package to use.
13740 @deftp {Data Type} tailon-configuration-file
13741 Data type representing the configuration options for Tailon.
13742 This type has the following parameters:
13745 @item @code{files} (default: @code{(list "/var/log")})
13746 List of files to display. The list can include strings for a single file
13747 or directory, or a list, where the first item is the name of a
13748 subsection, and the remaining items are the files or directories in that
13751 @item @code{bind} (default: @code{"localhost:8080"})
13752 Address and port to which Tailon should bind on.
13754 @item @code{relative-root} (default: @code{#f})
13755 URL path to use for Tailon, set to @code{#f} to not use a path.
13757 @item @code{allow-transfers?} (default: @code{#t})
13758 Allow downloading the log files in the web interface.
13760 @item @code{follow-names?} (default: @code{#t})
13761 Allow tailing of not-yet existent files.
13763 @item @code{tail-lines} (default: @code{200})
13764 Number of lines to read initially from each file.
13766 @item @code{allowed-commands} (default: @code{(list "tail" "grep" "awk")})
13767 Commands to allow running. By default, @code{sed} is disabled.
13769 @item @code{debug?} (default: @code{#f})
13770 Set @code{debug?} to @code{#t} to show debug messages.
13772 @item @code{wrap-lines} (default: @code{#t})
13773 Initial line wrapping state in the web interface. Set to @code{#t} to
13774 initially wrap lines (the default), or to @code{#f} to initially not
13777 @item @code{http-auth} (default: @code{#f})
13778 HTTP authentication type to use. Set to @code{#f} to disable
13779 authentication (the default). Supported values are @code{"digest"} or
13782 @item @code{users} (default: @code{#f})
13783 If HTTP authentication is enabled (see @code{http-auth}), access will be
13784 restricted to the credentials provided here. To configure users, use a
13785 list of pairs, where the first element of the pair is the username, and
13786 the 2nd element of the pair is the password.
13789 (tailon-configuration-file
13790 (http-auth "basic")
13791 (users '(("user1" . "password1")
13792 ("user2" . "password2"))))
13799 @node Kerberos Services
13800 @subsubsection Kerberos Services
13803 The @code{(gnu services kerberos)} module provides services relating to
13804 the authentication protocol @dfn{Kerberos}.
13806 @subsubheading Krb5 Service
13808 Programs using a Kerberos client library normally
13809 expect a configuration file in @file{/etc/krb5.conf}.
13810 This service generates such a file from a definition provided in the
13811 operating system declaration.
13812 It does not cause any daemon to be started.
13814 No ``keytab'' files are provided by this service---you must explicitly create them.
13815 This service is known to work with the MIT client library, @code{mit-krb5}.
13816 Other implementations have not been tested.
13818 @defvr {Scheme Variable} krb5-service-type
13819 A service type for Kerberos 5 clients.
13823 Here is an example of its use:
13825 (service krb5-service-type
13826 (krb5-configuration
13827 (default-realm "EXAMPLE.COM")
13828 (allow-weak-crypto? #t)
13831 (name "EXAMPLE.COM")
13832 (admin-server "groucho.example.com")
13833 (kdc "karl.example.com"))
13836 (admin-server "kerb-admin.argrx.edu")
13837 (kdc "keys.argrx.edu"))))))
13841 This example provides a Kerberos@tie{}5 client configuration which:
13843 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13844 of which have distinct administration servers and key distribution centers;
13845 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13846 specified by clients;
13847 @item Accepts services which only support encryption types known to be weak.
13850 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13851 Only the most commonly used ones are described here.
13852 For a full list, and more detailed explanation of each, see the MIT
13853 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13857 @deftp {Data Type} krb5-realm
13858 @cindex realm, kerberos
13861 This field is a string identifying the name of the realm.
13862 A common convention is to use the fully qualified DNS name of your organization,
13863 converted to upper case.
13865 @item @code{admin-server}
13866 This field is a string identifying the host where the administration server is
13870 This field is a string identifying the key distribution center
13875 @deftp {Data Type} krb5-configuration
13878 @item @code{allow-weak-crypto?} (default: @code{#f})
13879 If this flag is @code{#t} then services which only offer encryption algorithms
13880 known to be weak will be accepted.
13882 @item @code{default-realm} (default: @code{#f})
13883 This field should be a string identifying the default Kerberos
13884 realm for the client.
13885 You should set this field to the name of your Kerberos realm.
13886 If this value is @code{#f}
13887 then a realm must be specified with every Kerberos principal when invoking programs
13888 such as @command{kinit}.
13890 @item @code{realms}
13891 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13893 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13899 @subsubheading PAM krb5 Service
13902 The @code{pam-krb5} service allows for login authentication and password
13903 management via Kerberos.
13904 You will need this service if you want PAM enabled applications to authenticate
13905 users using Kerberos.
13907 @defvr {Scheme Variable} pam-krb5-service-type
13908 A service type for the Kerberos 5 PAM module.
13911 @deftp {Data Type} pam-krb5-configuration
13912 Data type representing the configuration of the Kerberos 5 PAM module
13913 This type has the following parameters:
13915 @item @code{pam-krb5} (default: @code{pam-krb5})
13916 The pam-krb5 package to use.
13918 @item @code{minimum-uid} (default: @code{1000})
13919 The smallest user ID for which Kerberos authentications should be attempted.
13920 Local accounts with lower values will silently fail to authenticate.
13926 @subsubsection Web Services
13931 The @code{(gnu services web)} module provides the nginx web server and
13932 also a fastcgi wrapper daemon.
13934 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
13935 [#:log-directory ``/var/log/nginx''] @
13936 [#:run-directory ``/var/run/nginx''] @
13937 [#:server-list '()] @
13938 [#:upstream-list '()] @
13939 [#:config-file @code{#f}]
13941 Return a service that runs @var{nginx}, the nginx web server.
13943 The nginx daemon loads its runtime configuration from @var{config-file}.
13944 Log files are written to @var{log-directory} and temporary runtime data
13945 files are written to @var{run-directory}. For proper operation, these
13946 arguments should match what is in @var{config-file} to ensure that the
13947 directories are created when the service is activated.
13949 As an alternative to using a @var{config-file}, @var{server-list} can be
13950 used to specify the list of @dfn{server blocks} required on the host and
13951 @var{upstream-list} can be used to specify a list of @dfn{upstream
13952 blocks} to configure. For this to work, use the default value for
13955 At startup, @command{nginx} has not yet read its configuration file, so it
13956 uses a default file to log error messages. If it fails to load its
13957 configuration file, that is where error messages are logged. After the
13958 configuration file is loaded, the default error log file changes as per
13959 configuration. In our case, startup error messages can be found in
13960 @file{/var/run/nginx/logs/error.log}, and after configuration in
13961 @file{/var/log/nginx/error.log}. The second location can be changed with the
13962 @var{log-directory} configuration option.
13966 @deffn {Scheme Variable} nginx-service-type
13967 This is type for the nginx web server.
13969 This service can be extended to add server blocks in addition to the
13970 default one, as in this example:
13973 (simple-service 'my-extra-server nginx-service-type
13974 (list (nginx-server-configuration
13976 (root "/srv/http/extra-website"))))
13980 @deftp {Data Type} nginx-server-configuration
13981 Data type representing the configuration of an nginx server block.
13982 This type has the following parameters:
13985 @item @code{http-port} (default: @code{80})
13986 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
13987 nginx should not listen for HTTP (non secure) connection for this
13988 @dfn{server block}.
13990 @item @code{https-port} (default: @code{443})
13991 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
13992 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
13994 Note that nginx can listen for HTTP and HTTPS connections in the same
13995 @dfn{server block}.
13997 @item @code{server-name} (default: @code{(list 'default)})
13998 A list of server names this server represents. @code{'default} represents the
13999 default server for connections matching no other server.
14001 @item @code{root} (default: @code{"/srv/http"})
14002 Root of the website nginx will serve.
14004 @item @code{locations} (default: @code{'()})
14005 A list of @dfn{nginx-location-configuration} or
14006 @dfn{nginx-named-location-configuration} records to use within this
14009 @item @code{index} (default: @code{(list "index.html")})
14010 Index files to look for when clients ask for a directory. If it cannot be found,
14011 Nginx will send the list of files in the directory.
14013 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
14014 Where to find the certificate for secure connections. Set it to @code{#f} if
14015 you don't have a certificate or you don't want to use HTTPS.
14017 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
14018 Where to find the private key for secure connections. Set it to @code{#f} if
14019 you don't have a key or you don't want to use HTTPS.
14021 @item @code{server-tokens?} (default: @code{#f})
14022 Whether the server should add its configuration to response.
14027 @deftp {Data Type} nginx-upstream-configuration
14028 Data type representing the configuration of an nginx @code{upstream}
14029 block. This type has the following parameters:
14033 Name for this group of servers.
14035 @item @code{servers}
14036 Specify the addresses of the servers in the group. The address can be
14037 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
14038 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
14039 prefix @samp{unix:}. For addresses using an IP address or domain name,
14040 the default port is 80, and a different port can be specified
14046 @deftp {Data Type} nginx-location-configuration
14047 Data type representing the configuration of an nginx @code{location}
14048 block. This type has the following parameters:
14052 URI which this location block matches.
14054 @anchor{nginx-location-configuration body}
14056 Body of the location block, specified as a string. This can contain many
14057 configuration directives. For example, to pass requests to a upstream
14058 server group defined using an @code{nginx-upstream-configuration} block,
14059 the following directive would be specified in the body @samp{proxy_pass
14060 http://upstream-name;}.
14065 @deftp {Data Type} nginx-named-location-configuration
14066 Data type representing the configuration of an nginx named location
14067 block. Named location blocks are used for request redirection, and not
14068 used for regular request processing. This type has the following
14073 Name to identify this location block.
14076 @xref{nginx-location-configuration body}, as the body for named location
14077 blocks can be used in a similar way to the
14078 @code{nginx-location-configuration body}. One restriction is that the
14079 body of a named location block cannot contain location blocks.
14086 FastCGI is an interface between the front-end and the back-end of a web
14087 service. It is a somewhat legacy facility; new web services should
14088 generally just talk HTTP between the front-end and the back-end.
14089 However there are a number of back-end services such as PHP or the
14090 optimized HTTP Git repository access that use FastCGI, so we have
14091 support for it in Guix.
14093 To use FastCGI, you configure the front-end web server (e.g., nginx) to
14094 dispatch some subset of its requests to the fastcgi backend, which
14095 listens on a local TCP or UNIX socket. There is an intermediary
14096 @code{fcgiwrap} program that sits between the actual backend process and
14097 the web server. The front-end indicates which backend program to run,
14098 passing that information to the @code{fcgiwrap} process.
14100 @defvr {Scheme Variable} fcgiwrap-service-type
14101 A service type for the @code{fcgiwrap} FastCGI proxy.
14104 @deftp {Data Type} fcgiwrap-configuration
14105 Data type representing the configuration of the @code{fcgiwrap} serice.
14106 This type has the following parameters:
14108 @item @code{package} (default: @code{fcgiwrap})
14109 The fcgiwrap package to use.
14111 @item @code{socket} (default: @code{tcp:127.0.0.1:9000})
14112 The socket on which the @code{fcgiwrap} process should listen, as a
14113 string. Valid @var{socket} values include
14114 @code{unix:@var{/path/to/unix/socket}},
14115 @code{tcp:@var{dot.ted.qu.ad}:@var{port}} and
14116 @code{tcp6:[@var{ipv6_addr}]:port}.
14118 @item @code{user} (default: @code{fcgiwrap})
14119 @itemx @code{group} (default: @code{fcgiwrap})
14120 The user and group names, as strings, under which to run the
14121 @code{fcgiwrap} process. The @code{fastcgi} service will ensure that if
14122 the user asks for the specific user or group names @code{fcgiwrap} that
14123 the corresponding user and/or group is present on the system.
14125 It is possible to configure a FastCGI-backed web service to pass HTTP
14126 authentication information from the front-end to the back-end, and to
14127 allow @code{fcgiwrap} to run the back-end process as a corresponding
14128 local user. To enable this capability on the back-end., run
14129 @code{fcgiwrap} as the @code{root} user and group. Note that this
14130 capability also has to be configured on the front-end as well.
14136 @subsubsection DNS Services
14137 @cindex DNS (domain name system)
14138 @cindex domain name system (DNS)
14140 The @code{(gnu services dns)} module provides services related to the
14141 @dfn{domain name system} (DNS). It provides a server service for hosting
14142 an @emph{authoritative} DNS server for multiple zones, slave or master.
14143 This service uses @uref{https://www.knot-dns.cz/, Knot DNS}.
14145 An example configuration of an authoritative server for two zones, one master
14149 (define-zone-entries example.org.zone
14150 ;; Name TTL Class Type Data
14151 ("@@" "" "IN" "A" "127.0.0.1")
14152 ("@@" "" "IN" "NS" "ns")
14153 ("ns" "" "IN" "A" "127.0.0.1"))
14155 (define master-zone
14156 (knot-zone-configuration
14157 (domain "example.org")
14159 (origin "example.org")
14160 (entries example.org.zone)))))
14163 (knot-zone-configuration
14164 (domain "plop.org")
14165 (dnssec-policy "default")
14166 (master (list "plop-master"))))
14168 (define plop-master
14169 (knot-remote-configuration
14171 (address (list "208.76.58.171"))))
14175 (services (cons* (service knot-service-type
14176 (knot-confifguration
14177 (remotes (list plop-master))
14178 (zones (list master-zone slave-zone))))
14183 @deffn {Scheme Variable} knot-service-type
14184 This is the type for the Knot DNS server.
14186 Knot DNS is an authoritative DNS server, meaning that it can serve multiple
14187 zones, that is to say domain names you would buy from a registrar. This server
14188 is not a resolver, meaning that it can only resolve names for which it is
14189 authoritative. This server can be configured to serve zones as a master server
14190 or a slave server as a per-zone basis. Slave zones will get their data from
14191 masters, and will serve it as an authoritative server. From the point of view
14192 of a resolver, there is no difference between master and slave.
14194 The following data types are used to configure the Knot DNS server:
14197 @deftp {Data Type} knot-key-configuration
14198 Data type representing a key.
14199 This type has the following parameters:
14202 @item @code{id} (default: @code{""})
14203 An identifier for other configuration fields to refer to this key. IDs must
14204 be unique and must not be empty.
14206 @item @code{algorithm} (default: @code{#f})
14207 The algorithm to use. Choose between @code{#f}, @code{'hmac-md5},
14208 @code{'hmac-sha1}, @code{'hmac-sha224}, @code{'hmac-sha256}, @code{'hmac-sha384}
14209 and @code{'hmac-sha512}.
14211 @item @code{secret} (default: @code{""})
14212 The secret key itself.
14217 @deftp {Data Type} knot-acl-configuration
14218 Data type representing an Access Control List (ACL) configuration.
14219 This type has the following parameters:
14222 @item @code{id} (default: @code{""})
14223 An identifier for ether configuration fields to refer to this key. IDs must be
14224 unique and must not be empty.
14226 @item @code{address} (default: @code{'()})
14227 An ordered list of IP addresses, network subnets, or network ranges represented
14228 with strings. The query must match one of them. Empty value means that
14229 address match is not required.
14231 @item @code{key} (default: @code{'()})
14232 An ordered list of references to keys represented with strings. The string
14233 must match a key ID defined in a @code{knot-key-configuration}. No key means
14234 that a key is not require to match that ACL.
14236 @item @code{action} (default: @code{'()})
14237 An ordered list of actions that are permitted or forbidden by this ACL. Possible
14238 values are lists of zero or more elements from @code{'transfer}, @code{'notify}
14239 and @code{'update}.
14241 @item @code{deny?} (default: @code{#f})
14242 When true, the ACL defines restrictions. Listed actions are forbidden. When
14243 false, listed actions are allowed.
14248 @deftp {Data Type} zone-entry
14249 Data type represnting a record entry in a zone file.
14250 This type has the following parameters:
14253 @item @code{name} (default: @code{"@@"})
14254 The name of the record. @code{"@@"} refers to the origin of the zone. Names
14255 are relative to the origin of the zone. For example, in the @code{example.org}
14256 zone, @code{"ns.example.org"} actually refers to @code{ns.example.org.example.org}.
14257 Names ending with a dot are absolute, which means that @code{"ns.example.org."}
14258 refers to @code{ns.example.org}.
14260 @item @code{ttl} (default: @code{""})
14261 The Time-To-Live (TTL) of this record. If not set, the default TTL is used.
14263 @item @code{class} (default: @code{"IN"})
14264 The class of the record. Knot currently supports only @code{"IN"} and
14265 partially @code{"CH"}.
14267 @item @code{type} (default: @code{"A"})
14268 The type of the record. Common types include A (IPv4 address), AAAA (IPv6
14269 address), NS (Name Server) and MX (Mail eXchange). Many other types are
14272 @item @code{data} (default: @code{""})
14273 The data contained in the record. For instance an IP address associated with
14274 an A record, or a domain name associated with an NS record. Remember that
14275 domain names are relative to the origin unless they end with a dot.
14280 @deftp {Data Type} zone-file
14281 Data type representing the content of a zone file.
14282 This type has the following parameters:
14285 @item @code{entries} (default: @code{'()})
14286 The list of entries. The SOA record is taken care of, so you don't need to
14287 put it in the list of entries. This list should probably contain an entry
14288 for your primary authoritative DNS server. Other than using a list of entries
14289 directly, you can use @code{define-zone-entries} to define a object containing
14290 the list of entries more easily, that you can later pass to the @code{entries}
14291 field of the @code{zone-file}.
14293 @item @code{origin} (default: @code{""})
14294 The name of your zone. This parameter cannot be empty.
14296 @item @code{ns} (default: @code{"ns"})
14297 The domain of your primary authoritative DNS server. The name is relative to
14298 the origin, unless it ends with a dot. It is mandatory that this primary
14299 DNS server corresponds to an NS record in the zone and that it is associated
14300 to an IP address in the list of entries.
14302 @item @code{mail} (default: @code{"hostmaster"})
14303 An email address people can contact you at, as the owner of the zone. This
14304 is translated as @code{<mail>@@<origin>}.
14306 @item @code{serial} (default: @code{1})
14307 The serial number of the zone. As this is used to keep track of changes by
14308 both slaves and resolvers, it is mandatory that it @emph{never} decreases.
14309 Always increment it when you make a change in your zone.
14311 @item @code{refresh} (default: @code{(* 2 24 3600)})
14312 The frequency at which slaves will do a zone transfer. This value is a number
14313 of seconds. It can be computed by multiplications or with
14314 @code{(string->duration)}.
14316 @item @code{retry} (default: @code{(* 15 60)})
14317 The period after which a slave will retry to contact its master when it fails
14318 to do so a first time.
14320 @item @code{expiry} (default: @code{(* 14 24 3600)})
14321 Default TTL of records. Existing records are considered correct for at most
14322 this amount of time. After this period, resolvers will invalidate their cache
14323 and check again that it still exists.
14325 @item @code{nx} (default: @code{3600})
14326 Default TTL of inexistant records. This delay is usually short because you want
14327 your new domains to reach everyone quickly.
14332 @deftp {Data Type} knot-remote-configuration
14333 Data type representing a remote configuration.
14334 This type has the following parameters:
14337 @item @code{id} (default: @code{""})
14338 An identifier for other configuration fields to refer to this remote. IDs must
14339 be unique and must not be empty.
14341 @item @code{address} (default: @code{'()})
14342 An ordered list of destination IP addresses. Addresses are tried in sequence.
14343 An optional port can be given with the @@ separator. For instance:
14344 @code{(list "1.2.3.4" "2.3.4.5@@53")}. Default port is 53.
14346 @item @code{via} (default: @code{'()})
14347 An ordered list of source IP addresses. An empty list will have Knot choose
14348 an appropriate source IP. An optional port can be given with the @@ separator.
14349 The default is to choose at random.
14351 @item @code{key} (default: @code{#f})
14352 A reference to a key, that is a string containing the identifier of a key
14353 defined in a @code{knot-key-configuration} field.
14358 @deftp {Data Type} knot-keystore-configuration
14359 Data type representing a keystore to hold dnssec keys.
14360 This type has the following parameters:
14363 @item @code{id} (default: @code{""})
14364 The id of the keystore. It must not be empty.
14366 @item @code{backend} (default: @code{'pem})
14367 The backend to store the keys in. Can be @code{'pem} or @code{'pkcs11}.
14369 @item @code{config} (default: @code{"/var/lib/knot/keys/keys"})
14370 The configuration string of the backend. An example for the PKCS#11 is:
14371 @code{"pkcs11:token=knot;pin-value=1234 /gnu/store/.../lib/pkcs11/libsofthsm2.so"}.
14372 For the pem backend, the string reprensents a path in the filesystem.
14377 @deftp {Data Type} knot-policy-configuration
14378 Data type representing a dnssec policy. Knot DNS is able to automatically
14379 sign your zones. It can either generate and manage your keys automatically or
14380 use keys that you generate.
14382 Dnssec is usually implemented using two keys: a Key Signing Key (KSK) that is
14383 used to sign the second, and a Zone Signing Key (ZSK) that is used to sign the
14384 zone. In order to be trusted, the KSK needs to be present in the parent zone
14385 (usually a top-level domain). If your registrar supports dnssec, you will
14386 have to send them your KSK's hash so they can add a DS record in their zone.
14387 This is not automated and need to be done each time you change your KSK.
14389 The policy also defines the lifetime of keys. Usually, ZSK can be changed
14390 easily and use weaker cryptographic functions (they use lower parameters) in
14391 order to sign records quickly, so they are changed often. The KSK however
14392 requires manual interaction with the registrar, so they are changed less often
14393 and use stronger parameters because they sign only one record.
14395 This type has the following parameters:
14398 @item @code{id} (default: @code{""})
14399 The id of the policy. It must not be empty.
14401 @item @code{keystore} (default: @code{"default"})
14402 A reference to a keystore, that is a string containing the identifier of a
14403 keystore defined in a @code{knot-keystore-configuration} field. The
14404 @code{"default"} identifier means the default keystore (a kasp database that
14405 was setup by this service).
14407 @item @code{manual?} (default: @code{#f})
14408 Whether the key management is manual or automatic.
14410 @item @code{single-type-signing?} (default: @code{#f})
14411 When @code{#t}, use the Single-Type Signing Scheme.
14413 @item @code{algorithm} (default: @code{"ecdsap256sha256"})
14414 An algorithm of signing keys and issued signatures.
14416 @item @code{ksk-size} (default: @code{256})
14417 The length of the KSK. Note that this value is correct for the default
14418 algorithm, but would be unsecure for other algorithms.
14420 @item @code{zsk-size} (default: @code{256})
14421 The length of the ZSK. Note that this value is correct for the default
14422 algorithm, but would be unsecure for other algorithms.
14424 @item @code{dnskey-ttl} (default: @code{'default})
14425 The TTL value for DNSKEY records added into zone apex. The special
14426 @code{'default} value means same as the zone SOA TTL.
14428 @item @code{zsk-lifetime} (default: @code{(* 30 24 3600)})
14429 The period between ZSK publication and the next rollover initiation.
14431 @item @code{propagation-delay} (default: @code{(* 24 3600)})
14432 An extra delay added for each key rollover step. This value should be high
14433 enough to cover propagation of data from the master server to all slaves.
14435 @item @code{rrsig-lifetime} (default: @code{(* 14 24 3600)})
14436 A validity period of newly issued signatures.
14438 @item @code{rrsig-refresh} (default: @code{(* 7 24 3600)})
14439 A period how long before a signature expiration the signature will be refreshed.
14441 @item @code{nsec3?} (default: @code{#f})
14442 When @code{#t}, NSEC3 will be used instead of NSEC.
14444 @item @code{nsec3-iterations} (default: @code{5})
14445 The number of additional times the hashing is performed.
14447 @item @code{nsec3-salt-length} (default: @code{8})
14448 The length of a salt field in octets, which is appended to the original owner
14449 name before hashing.
14451 @item @code{nsec3-salt-lifetime} (default: @code{(* 30 24 3600)})
14452 The validity period of newly issued salt field.
14457 @deftp {Data Type} knot-zone-configuration
14458 Data type representing a zone served by Knot.
14459 This type has the following parameters:
14462 @item @code{domain} (default: @code{""})
14463 The domain served by this configuration. It must not be empty.
14465 @item @code{file} (default: @code{""})
14466 The file where this zone is saved. This parameter is ignored by master zones.
14467 Empty means default location that depends on the domain name.
14469 @item @code{zone} (default: @code{(zone-file)})
14470 The content of the zone file. This parameter is ignored by slave zones. It
14471 must contain a zone-file record.
14473 @item @code{master} (default: @code{'()})
14474 A list of master remotes. When empty, this zone is a master. When set, this
14475 zone is a slave. This is a list of remotes identifiers.
14477 @item @code{ddns-master} (default: @code{#f})
14478 The main master. When empty, it defaults to the first master in the list of
14481 @item @code{notify} (default: @code{'()})
14482 A list of slave remote identifiers.
14484 @item @code{acl} (default: @code{'()})
14485 A list of acl identifiers.
14487 @item @code{semantic-checks?} (default: @code{#f})
14488 When set, this adds more semantic checks to the zone.
14490 @item @code{disable-any?} (default: @code{#f})
14491 When set, this forbids queries of the ANY type.
14493 @item @code{zonefile-sync} (default: @code{0})
14494 The delay between a modification in memory and on disk. 0 means immediate
14497 @item @code{serial-policy} (default: @code{'increment})
14498 A policy between @code{'increment} and @code{'unixtime}.
14503 @deftp {Data Type} knot-configuration
14504 Data type representing the Knot configuration.
14505 This type has the following parameters:
14508 @item @code{knot} (default: @code{knot})
14511 @item @code{run-directory} (default: @code{"/var/run/knot"})
14512 The run directory. This directory will be used for pid file and sockets.
14514 @item @code{listen-v4} (default: @code{"0.0.0.0"})
14515 An ip address on which to listen.
14517 @item @code{listen-v6} (default: @code{"::"})
14518 An ip address on which to listen.
14520 @item @code{listen-port} (default: @code{53})
14521 A port on which to listen.
14523 @item @code{keys} (default: @code{'()})
14524 The list of knot-key-configuration used by this configuration.
14526 @item @code{acls} (default: @code{'()})
14527 The list of knot-acl-configuration used by this configuration.
14529 @item @code{remotes} (default: @code{'()})
14530 The list of knot-remote-configuration used by this configuration.
14532 @item @code{zones} (default: @code{'()})
14533 The list of knot-zone-configuration used by this configuration.
14539 @subsubsection VPN Services
14540 @cindex VPN (virtual private network)
14541 @cindex virtual private network (VPN)
14543 The @code{(gnu services vpn)} module provides services related to
14544 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
14545 your machine to connect to a VPN, and a @emph{servire} service for your machine
14546 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
14548 @deffn {Scheme Procedure} openvpn-client-service @
14549 [#:config (openvpn-client-configuration)]
14551 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
14554 @deffn {Scheme Procedure} openvpn-server-service @
14555 [#:config (openvpn-server-configuration)]
14557 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
14559 Both can be run simultaneously.
14562 @c %automatically generated documentation
14564 Available @code{openvpn-client-configuration} fields are:
14566 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
14567 The OpenVPN package.
14571 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
14572 The OpenVPN pid file.
14574 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14578 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
14579 The protocol (UDP or TCP) used to open a channel between clients and
14582 Defaults to @samp{udp}.
14586 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
14587 The device type used to represent the VPN connection.
14589 Defaults to @samp{tun}.
14593 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
14594 The certificate authority to check connections against.
14596 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14600 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
14601 The certificate of the machine the daemon is running on. It should be
14602 signed by the authority given in @code{ca}.
14604 Defaults to @samp{"/etc/openvpn/client.crt"}.
14608 @deftypevr {@code{openvpn-client-configuration} parameter} string key
14609 The key of the machine the daemon is running on. It must be the key whose
14610 certificate is @code{cert}.
14612 Defaults to @samp{"/etc/openvpn/client.key"}.
14616 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
14617 Whether to use the lzo compression algorithm.
14619 Defaults to @samp{#t}.
14623 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
14624 Don't re-read key files across SIGUSR1 or --ping-restart.
14626 Defaults to @samp{#t}.
14630 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
14631 Don't close and reopen TUN/TAP device or run up/down scripts across
14632 SIGUSR1 or --ping-restart restarts.
14634 Defaults to @samp{#t}.
14638 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
14641 Defaults to @samp{3}.
14645 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
14646 Add an additional layer of HMAC authentication on top of the TLS control
14647 channel to protect against DoS attacks.
14649 Defaults to @samp{#f}.
14653 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
14654 Whether to check the server certificate has server usage extension.
14656 Defaults to @samp{#t}.
14660 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
14661 Bind to a specific local port number.
14663 Defaults to @samp{#f}.
14667 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
14668 Retry resolving server address.
14670 Defaults to @samp{#t}.
14674 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
14675 A list of remote servers to connect to.
14677 Defaults to @samp{()}.
14679 Available @code{openvpn-remote-configuration} fields are:
14681 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
14684 Defaults to @samp{"my-server"}.
14688 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
14689 Port number the server listens to.
14691 Defaults to @samp{1194}.
14696 @c %end of automatic openvpn-client documentation
14698 @c %automatically generated documentation
14700 Available @code{openvpn-server-configuration} fields are:
14702 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
14703 The OpenVPN package.
14707 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
14708 The OpenVPN pid file.
14710 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14714 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
14715 The protocol (UDP or TCP) used to open a channel between clients and
14718 Defaults to @samp{udp}.
14722 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
14723 The device type used to represent the VPN connection.
14725 Defaults to @samp{tun}.
14729 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
14730 The certificate authority to check connections against.
14732 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14736 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
14737 The certificate of the machine the daemon is running on. It should be
14738 signed by the authority given in @code{ca}.
14740 Defaults to @samp{"/etc/openvpn/client.crt"}.
14744 @deftypevr {@code{openvpn-server-configuration} parameter} string key
14745 The key of the machine the daemon is running on. It must be the key whose
14746 certificate is @code{cert}.
14748 Defaults to @samp{"/etc/openvpn/client.key"}.
14752 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
14753 Whether to use the lzo compression algorithm.
14755 Defaults to @samp{#t}.
14759 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
14760 Don't re-read key files across SIGUSR1 or --ping-restart.
14762 Defaults to @samp{#t}.
14766 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
14767 Don't close and reopen TUN/TAP device or run up/down scripts across
14768 SIGUSR1 or --ping-restart restarts.
14770 Defaults to @samp{#t}.
14774 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
14777 Defaults to @samp{3}.
14781 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
14782 Add an additional layer of HMAC authentication on top of the TLS control
14783 channel to protect against DoS attacks.
14785 Defaults to @samp{#f}.
14789 @deftypevr {@code{openvpn-server-configuration} parameter} number port
14790 Specifies the port number on which the server listens.
14792 Defaults to @samp{1194}.
14796 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
14797 An ip and mask specifying the subnet inside the virtual network.
14799 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
14803 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
14804 A CIDR notation specifying the IPv6 subnet inside the virtual network.
14806 Defaults to @samp{#f}.
14810 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
14811 The Diffie-Hellman parameters file.
14813 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
14817 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
14818 The file that records client IPs.
14820 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
14824 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
14825 When true, the server will act as a gateway for its clients.
14827 Defaults to @samp{#f}.
14831 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
14832 When true, clients are allowed to talk to each other inside the VPN.
14834 Defaults to @samp{#f}.
14838 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
14839 Causes ping-like messages to be sent back and forth over the link so
14840 that each side knows when the other side has gone down. @code{keepalive}
14841 requires a pair. The first element is the period of the ping sending,
14842 and the second element is the timeout before considering the other side
14847 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
14848 The maximum number of clients.
14850 Defaults to @samp{100}.
14854 @deftypevr {@code{openvpn-server-configuration} parameter} string status
14855 The status file. This file shows a small report on current connection.
14856 It is truncated and rewritten every minute.
14858 Defaults to @samp{"/var/run/openvpn/status"}.
14862 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
14863 The list of configuration for some clients.
14865 Defaults to @samp{()}.
14867 Available @code{openvpn-ccd-configuration} fields are:
14869 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
14872 Defaults to @samp{"client"}.
14876 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
14879 Defaults to @samp{#f}.
14883 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
14886 Defaults to @samp{#f}.
14893 @c %end of automatic openvpn-server documentation
14896 @node Network File System
14897 @subsubsection Network File System
14900 The @code{(gnu services nfs)} module provides the following services,
14901 which are most commonly used in relation to mounting or exporting
14902 directory trees as @dfn{network file systems} (NFS).
14904 @subsubheading RPC Bind Service
14907 The RPC Bind service provides a facility to map program numbers into
14908 universal addresses.
14909 Many NFS related services use this facility. Hence it is automatically
14910 started when a dependent service starts.
14912 @defvr {Scheme Variable} rpcbind-service-type
14913 A service type for the RPC portmapper daemon.
14917 @deftp {Data Type} rpcbind-configuration
14918 Data type representing the configuration of the RPC Bind Service.
14919 This type has the following parameters:
14921 @item @code{rpcbind} (default: @code{rpcbind})
14922 The rpcbind package to use.
14924 @item @code{warm-start?} (default: @code{#t})
14925 If this parameter is @code{#t}, then the daemon will read a
14926 state file on startup thus reloading state information saved by a previous
14932 @subsubheading Pipefs Pseudo File System
14936 The pipefs file system is used to transfer NFS related data
14937 between the kernel and user space programs.
14939 @defvr {Scheme Variable} pipefs-service-type
14940 A service type for the pipefs pseudo file system.
14943 @deftp {Data Type} pipefs-configuration
14944 Data type representing the configuration of the pipefs pseudo file system service.
14945 This type has the following parameters:
14947 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14948 The directory to which the file system is to be attached.
14953 @subsubheading GSS Daemon Service
14956 @cindex global security system
14958 The @dfn{global security system} (GSS) daemon provides strong security for RPC
14960 Before exchanging RPC requests an RPC client must establish a security
14961 context. Typically this is done using the Kerberos command @command{kinit}
14962 or automatically at login time using PAM services (@pxref{Kerberos Services}).
14964 @defvr {Scheme Variable} gss-service-type
14965 A service type for the Global Security System (GSS) daemon.
14968 @deftp {Data Type} gss-configuration
14969 Data type representing the configuration of the GSS daemon service.
14970 This type has the following parameters:
14972 @item @code{nfs-utils} (default: @code{nfs-utils})
14973 The package in which the @command{rpc.gssd} command is to be found.
14975 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14976 The directory where the pipefs file system is mounted.
14982 @subsubheading IDMAP Daemon Service
14984 @cindex name mapper
14986 The idmap daemon service provides mapping between user IDs and user names.
14987 Typically it is required in order to access file systems mounted via NFSv4.
14989 @defvr {Scheme Variable} idmap-service-type
14990 A service type for the Identity Mapper (IDMAP) daemon.
14993 @deftp {Data Type} idmap-configuration
14994 Data type representing the configuration of the IDMAP daemon service.
14995 This type has the following parameters:
14997 @item @code{nfs-utils} (default: @code{nfs-utils})
14998 The package in which the @command{rpc.idmapd} command is to be found.
15000 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
15001 The directory where the pipefs file system is mounted.
15003 @item @code{domain} (default: @code{#f})
15004 The local NFSv4 domain name.
15005 This must be a string or @code{#f}.
15006 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
15011 @node Continuous Integration
15012 @subsubsection Continuous Integration
15014 @cindex continuous integration
15015 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
15016 integration tool for Guix. It can be used both for development and for
15017 providing substitutes to others (@pxref{Substitutes}).
15019 The @code{(gnu services cuirass)} module provides the following service.
15021 @defvr {Scheme Procedure} cuirass-service-type
15022 The type of the Cuirass service. Its value must be a
15023 @code{cuirass-configuration} object, as described below.
15026 To add build jobs, you have to set the @code{specifications} field of
15027 the configuration. Here is an example of a service defining a build job
15028 based on a specification that can be found in Cuirass source tree. This
15029 service polls the Guix repository and builds a subset of the Guix
15030 packages, as prescribed in the @file{gnu-system.scm} example spec:
15033 (let ((spec #~((#:name . "guix")
15034 (#:url . "git://git.savannah.gnu.org/guix.git")
15035 (#:load-path . ".")
15037 ;; Here we must provide an absolute file name.
15038 ;; We take jobs from one of the examples provided
15040 (#:file . #$(file-append
15042 "/tests/gnu-system.scm"))
15044 (#:proc . hydra-jobs)
15045 (#:arguments (subset . "hello"))
15046 (#:branch . "master"))))
15047 (service cuirass-service-type
15048 (cuirass-configuration
15049 (specifications #~(list #$spec)))))
15052 While information related to build jobs is located directly in the
15053 specifications, global settings for the @command{cuirass} process are
15054 accessible in other @code{cuirass-configuration} fields.
15056 @deftp {Data Type} cuirass-configuration
15057 Data type representing the configuration of Cuirass.
15060 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
15061 Location of the log file.
15063 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
15064 Location of the repository cache.
15066 @item @code{user} (default: @code{"cuirass"})
15067 Owner of the @code{cuirass} process.
15069 @item @code{group} (default: @code{"cuirass"})
15070 Owner's group of the @code{cuirass} process.
15072 @item @code{interval} (default: @code{60})
15073 Number of seconds between the poll of the repositories followed by the
15076 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
15077 Location of sqlite database which contains the build results and previously
15078 added specifications.
15080 @item @code{port} (default: @code{8080})
15081 Port number used by the HTTP server.
15083 @item @code{specifications} (default: @code{#~'()})
15084 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
15085 where a specification is an association list
15086 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
15087 keys are keywords (@code{#:keyword-example}) as shown in the example
15090 @item @code{use-substitutes?} (default: @code{#f})
15091 This allows using substitutes to avoid building every dependencies of a job
15094 @item @code{one-shot?} (default: @code{#f})
15095 Only evaluate specifications and build derivations once.
15097 @item @code{fallback?} (default: @code{#f})
15098 When substituting a pre-built binary fails, fall back to building
15101 @item @code{load-path} (default: @code{'()})
15102 This allows users to define their own packages and make them visible to
15103 cuirass as in @command{guix build} command.
15105 @item @code{cuirass} (default: @code{cuirass})
15106 The Cuirass package to use.
15110 @node Power management Services
15111 @subsubsection Power management Services
15113 @cindex power management with TLP
15114 The @code{(gnu services pm)} module provides a Guix service definition
15115 for the Linux power management tool TLP.
15117 TLP enables various powersaving modes in userspace and kernel.
15118 Contrary to @code{upower-service}, it is not a passive,
15119 monitoring tool, as it will apply custom settings each time a new power
15120 source is detected. More information can be found at
15121 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
15123 @deffn {Scheme Variable} tlp-service-type
15124 The service type for the TLP tool. Its value should be a valid
15125 TLP configuration (see below). To use the default settings, simply
15128 (service tlp-service-type)
15132 By default TLP does not need much configuration but most TLP parameters
15133 can be tweaked using @code{tlp-configuration}.
15135 Each parameter definition is preceded by its type; for example,
15136 @samp{boolean foo} indicates that the @code{foo} parameter
15137 should be specified as a boolean. Types starting with
15138 @code{maybe-} denote parameters that won't show up in TLP config file
15139 when their value is @code{'disabled}.
15141 @c The following documentation was initially generated by
15142 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
15143 @c documentation is better, so we shouldn't hesitate to edit below as
15144 @c needed. However if the change you want to make to this documentation
15145 @c can be done in an automated way, it's probably easier to change
15146 @c (generate-documentation) than to make it below and have to deal with
15147 @c the churn as TLP updates.
15149 Available @code{tlp-configuration} fields are:
15151 @deftypevr {@code{tlp-configuration} parameter} package tlp
15156 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
15157 Set to true if you wish to enable TLP.
15159 Defaults to @samp{#t}.
15163 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
15164 Default mode when no power supply can be detected. Alternatives are AC
15167 Defaults to @samp{"AC"}.
15171 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
15172 Number of seconds Linux kernel has to wait after the disk goes idle,
15173 before syncing on AC.
15175 Defaults to @samp{0}.
15179 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
15180 Same as @code{disk-idle-ac} but on BAT mode.
15182 Defaults to @samp{2}.
15186 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
15187 Dirty pages flushing periodicity, expressed in seconds.
15189 Defaults to @samp{15}.
15193 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
15194 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
15196 Defaults to @samp{60}.
15200 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
15201 CPU frequency scaling governor on AC mode. With intel_pstate driver,
15202 alternatives are powersave and performance. With acpi-cpufreq driver,
15203 alternatives are ondemand, powersave, performance and conservative.
15205 Defaults to @samp{disabled}.
15209 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
15210 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
15212 Defaults to @samp{disabled}.
15216 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
15217 Set the min available frequency for the scaling governor on AC.
15219 Defaults to @samp{disabled}.
15223 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
15224 Set the max available frequency for the scaling governor on AC.
15226 Defaults to @samp{disabled}.
15230 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
15231 Set the min available frequency for the scaling governor on BAT.
15233 Defaults to @samp{disabled}.
15237 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
15238 Set the max available frequency for the scaling governor on BAT.
15240 Defaults to @samp{disabled}.
15244 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
15245 Limit the min P-state to control the power dissipation of the CPU, in AC
15246 mode. Values are stated as a percentage of the available performance.
15248 Defaults to @samp{disabled}.
15252 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
15253 Limit the max P-state to control the power dissipation of the CPU, in AC
15254 mode. Values are stated as a percentage of the available performance.
15256 Defaults to @samp{disabled}.
15260 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
15261 Same as @code{cpu-min-perf-on-ac} on BAT mode.
15263 Defaults to @samp{disabled}.
15267 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
15268 Same as @code{cpu-max-perf-on-ac} on BAT mode.
15270 Defaults to @samp{disabled}.
15274 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
15275 Enable CPU turbo boost feature on AC mode.
15277 Defaults to @samp{disabled}.
15281 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
15282 Same as @code{cpu-boost-on-ac?} on BAT mode.
15284 Defaults to @samp{disabled}.
15288 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
15289 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
15290 used under light load conditions.
15292 Defaults to @samp{#f}.
15296 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
15297 Same as @code{sched-powersave-on-ac?} but on BAT mode.
15299 Defaults to @samp{#t}.
15303 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
15304 Enable Linux kernel NMI watchdog.
15306 Defaults to @samp{#f}.
15310 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
15311 For Linux kernels with PHC patch applied, change CPU voltages. An
15312 example value would be @samp{"F:V F:V F:V F:V"}.
15314 Defaults to @samp{disabled}.
15318 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
15319 Set CPU performance versus energy saving policy on AC. Alternatives are
15320 performance, normal, powersave.
15322 Defaults to @samp{"performance"}.
15326 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
15327 Same as @code{energy-perf-policy-ac} but on BAT mode.
15329 Defaults to @samp{"powersave"}.
15333 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
15338 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
15339 Hard disk advanced power management level.
15343 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
15344 Same as @code{disk-apm-bat} but on BAT mode.
15348 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
15349 Hard disk spin down timeout. One value has to be specified for each
15350 declared hard disk.
15352 Defaults to @samp{disabled}.
15356 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
15357 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
15359 Defaults to @samp{disabled}.
15363 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
15364 Select IO scheduler for disk devices. One value has to be specified for
15365 each declared hard disk. Example alternatives are cfq, deadline and
15368 Defaults to @samp{disabled}.
15372 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
15373 SATA aggressive link power management (ALPM) level. Alternatives are
15374 min_power, medium_power, max_performance.
15376 Defaults to @samp{"max_performance"}.
15380 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
15381 Same as @code{sata-linkpwr-ac} but on BAT mode.
15383 Defaults to @samp{"min_power"}.
15387 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
15388 Exclude specified SATA host devices for link power management.
15390 Defaults to @samp{disabled}.
15394 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
15395 Enable Runtime Power Management for AHCI controller and disks on AC
15398 Defaults to @samp{disabled}.
15402 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
15403 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
15405 Defaults to @samp{disabled}.
15409 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
15410 Seconds of inactivity before disk is suspended.
15412 Defaults to @samp{15}.
15416 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
15417 PCI Express Active State Power Management level. Alternatives are
15418 default, performance, powersave.
15420 Defaults to @samp{"performance"}.
15424 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
15425 Same as @code{pcie-aspm-ac} but on BAT mode.
15427 Defaults to @samp{"powersave"}.
15431 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
15432 Radeon graphics clock speed level. Alternatives are low, mid, high,
15435 Defaults to @samp{"high"}.
15439 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
15440 Same as @code{radeon-power-ac} but on BAT mode.
15442 Defaults to @samp{"low"}.
15446 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
15447 Radeon dynamic power management method (DPM). Alternatives are battery,
15450 Defaults to @samp{"performance"}.
15454 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
15455 Same as @code{radeon-dpm-state-ac} but on BAT mode.
15457 Defaults to @samp{"battery"}.
15461 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
15462 Radeon DPM performance level. Alternatives are auto, low, high.
15464 Defaults to @samp{"auto"}.
15468 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
15469 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
15471 Defaults to @samp{"auto"}.
15475 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
15476 Wifi power saving mode.
15478 Defaults to @samp{#f}.
15482 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
15483 Same as @code{wifi-power-ac?} but on BAT mode.
15485 Defaults to @samp{#t}.
15489 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
15490 Disable wake on LAN.
15492 Defaults to @samp{#t}.
15496 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
15497 Timeout duration in seconds before activating audio power saving on
15498 Intel HDA and AC97 devices. A value of 0 disables power saving.
15500 Defaults to @samp{0}.
15504 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
15505 Same as @code{sound-powersave-ac} but on BAT mode.
15507 Defaults to @samp{1}.
15511 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
15512 Disable controller in powersaving mode on Intel HDA devices.
15514 Defaults to @samp{#t}.
15518 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
15519 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
15520 powered on again by releasing (and reinserting) the eject lever or by
15521 pressing the disc eject button on newer models.
15523 Defaults to @samp{#f}.
15527 @deftypevr {@code{tlp-configuration} parameter} string bay-device
15528 Name of the optical drive device to power off.
15530 Defaults to @samp{"sr0"}.
15534 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
15535 Runtime Power Management for PCI(e) bus devices. Alternatives are on
15538 Defaults to @samp{"on"}.
15542 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
15543 Same as @code{runtime-pm-ac} but on BAT mode.
15545 Defaults to @samp{"auto"}.
15549 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
15550 Runtime Power Management for all PCI(e) bus devices, except blacklisted
15553 Defaults to @samp{#t}.
15557 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
15558 Exclude specified PCI(e) device addresses from Runtime Power Management.
15560 Defaults to @samp{disabled}.
15564 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
15565 Exclude PCI(e) devices assigned to the specified drivers from Runtime
15570 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
15571 Enable USB autosuspend feature.
15573 Defaults to @samp{#t}.
15577 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
15578 Exclude specified devices from USB autosuspend.
15580 Defaults to @samp{disabled}.
15584 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
15585 Exclude WWAN devices from USB autosuspend.
15587 Defaults to @samp{#t}.
15591 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
15592 Include specified devices into USB autosuspend, even if they are already
15593 excluded by the driver or via @code{usb-blacklist-wwan?}.
15595 Defaults to @samp{disabled}.
15599 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
15600 Enable USB autosuspend before shutdown.
15602 Defaults to @samp{disabled}.
15606 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
15607 Restore radio device state (bluetooth, wifi, wwan) from previous
15608 shutdown on system startup.
15610 Defaults to @samp{#f}.
15615 The @code{(gnu services pm)} module provides an interface to
15616 thermald, a CPU frequency scaling service which helps prevent overheating.
15618 @defvr {Scheme Variable} thermald-service-type
15619 This is the service type for
15620 @uref{https://01.org/linux-thermal-daemon/, thermald}, the Linux
15621 Thermal Daemon, which is responsible for controlling the thermal state
15622 of processors and preventing overheating.
15625 @deftp {Data Type} thermald-configuration
15626 Data type representing the configuration of @code{thermald-service-type}.
15629 @item @code{ignore-cpuid-check?} (default: @code{#f})
15630 Ignore cpuid check for supported CPU models.
15632 @item @code{thermald} (default: @var{thermald})
15633 Package object of thermald.
15639 @node Miscellaneous Services
15640 @subsubsection Miscellaneous Services
15643 @subsubheading System Control Service
15645 The @code{(gnu services sysctl)} provides a service to configure kernel
15646 parameters at boot.
15648 @defvr {Scheme Variable} sysctl-service-type
15649 The service type for @command{sysctl}, which modifies kernel parameters
15650 under @file{/proc/sys/}. To enable IPv4 forwarding, it can be
15654 (service sysctl-service-type
15655 (sysctl-configuration
15656 (settings '(("net.ipv4.ip_forward" . "1")))))
15660 @deftp {Data Type} sysctl-configuration
15661 The data type representing the configuration of @command{sysctl}.
15664 @item @code{sysctl} (default: @code{(file-append procps "/sbin/sysctl"})
15665 The @command{sysctl} executable to use.
15667 @item @code{settings} (default: @code{'()})
15668 An association list specifies kernel parameters and their values.
15673 @subsubheading Lirc Service
15675 The @code{(gnu services lirc)} module provides the following service.
15677 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
15678 [#:device #f] [#:driver #f] [#:config-file #f] @
15679 [#:extra-options '()]
15680 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
15681 decodes infrared signals from remote controls.
15683 Optionally, @var{device}, @var{driver} and @var{config-file}
15684 (configuration file name) may be specified. See @command{lircd} manual
15687 Finally, @var{extra-options} is a list of additional command-line options
15688 passed to @command{lircd}.
15692 @subsubheading Spice Service
15694 The @code{(gnu services spice)} module provides the following service.
15696 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
15697 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
15698 that enables sharing the clipboard with a vm and setting the guest display
15699 resolution when the graphical console window resizes.
15702 @subsubsection Dictionary Services
15704 The @code{(gnu services dict)} module provides the following service:
15706 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
15707 Return a service that runs the @command{dicod} daemon, an implementation
15708 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
15710 The optional @var{config} argument specifies the configuration for
15711 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
15712 default it serves the GNU Collaborative International Dictonary of English.
15714 You can add @command{open localhost} to your @file{~/.dico} file to make
15715 @code{localhost} the default server for @command{dico} client
15716 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
15719 @deftp {Data Type} dicod-configuration
15720 Data type representing the configuration of dicod.
15723 @item @code{dico} (default: @var{dico})
15724 Package object of the GNU Dico dictionary server.
15726 @item @code{interfaces} (default: @var{'("localhost")})
15727 This is the list of IP addresses and ports and possibly socket file
15728 names to listen to (@pxref{Server Settings, @code{listen} directive,,
15729 dico, GNU Dico Manual}).
15731 @item @code{handlers} (default: @var{'()})
15732 List of @code{<dicod-handler>} objects denoting handlers (module instances).
15734 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
15735 List of @code{<dicod-database>} objects denoting dictionaries to be served.
15739 @deftp {Data Type} dicod-handler
15740 Data type representing a dictionary handler (module instance).
15744 Name of the handler (module instance).
15746 @item @code{module} (default: @var{#f})
15747 Name of the dicod module of the handler (instance). If it is @code{#f},
15748 the module has the same name as the handler.
15749 (@pxref{Modules,,, dico, GNU Dico Manual}).
15751 @item @code{options}
15752 List of strings or gexps representing the arguments for the module handler
15756 @deftp {Data Type} dicod-database
15757 Data type representing a dictionary database.
15761 Name of the database, will be used in DICT commands.
15763 @item @code{handler}
15764 Name of the dicod handler (module instance) used by this database
15765 (@pxref{Handlers,,, dico, GNU Dico Manual}).
15767 @item @code{complex?} (default: @var{#f})
15768 Whether the database configuration complex. The complex configuration
15769 will need a corresponding @code{<dicod-handler>} object, otherwise not.
15771 @item @code{options}
15772 List of strings or gexps representing the arguments for the database
15773 (@pxref{Databases,,, dico, GNU Dico Manual}).
15777 @defvr {Scheme Variable} %dicod-database:gcide
15778 A @code{<dicod-database>} object serving the GNU Collaborative International
15779 Dictionary of English using the @code{gcide} package.
15782 The following is an example @code{dicod-service} configuration.
15785 (dicod-service #:config
15786 (dicod-configuration
15787 (handlers (list (dicod-handler
15791 (list #~(string-append "dbdir=" #$wordnet))))))
15792 (databases (list (dicod-database
15795 (handler "wordnet")
15796 (options '("database=wn")))
15797 %dicod-database:gcide))))
15800 @subsubsection Version Control
15802 The @code{(gnu services version-control)} module provides the following services:
15804 @subsubheading Git daemon service
15806 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
15808 Return a service that runs @command{git daemon}, a simple TCP server to
15809 expose repositories over the Git protocol for anonymous access.
15811 The optional @var{config} argument should be a
15812 @code{<git-daemon-configuration>} object, by default it allows read-only
15813 access to exported@footnote{By creating the magic file
15814 "git-daemon-export-ok" in the repository directory.} repositories under
15819 @deftp {Data Type} git-daemon-configuration
15820 Data type representing the configuration for @code{git-daemon-service}.
15823 @item @code{package} (default: @var{git})
15824 Package object of the Git distributed version control system.
15826 @item @code{export-all?} (default: @var{#f})
15827 Whether to allow access for all Git repositories, even if they do not
15828 have the @file{git-daemon-export-ok} file.
15830 @item @code{base-path} (default: @file{/srv/git})
15831 Whether to remap all the path requests as relative to the given path.
15832 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
15833 then if you later try to pull @code{git://example.com/hello.git}, git
15834 daemon will interpret the path as @code{/srv/git/hello.git}.
15836 @item @code{user-path} (default: @var{#f})
15837 Whether to allow @code{~user} notation to be used in requests. When
15838 specified with empty string, requests to @code{git://host/~alice/foo} is
15839 taken as a request to access @code{foo} repository in the home directory
15840 of user @code{alice}. If @var{(user-path "path")} is specified, the
15841 same request is taken as a request to access @code{path/foo} repository
15842 in the home directory of user @code{alice}.
15844 @item @code{listen} (default: @var{'()})
15845 Whether to listen on specific IP addresses or hostnames, defaults to
15848 @item @code{port} (default: @var{#f})
15849 Whether to listen on an alternative port, which defaults to 9418.
15851 @item @code{whitelist} (default: @var{'()})
15852 If not empty, only allow access to this list of directories.
15854 @item @code{extra-options} (default: @var{'()})
15855 Extra options will be passed to @code{git daemon}, please run
15856 @command{man git-daemon} for more information.
15861 @node Setuid Programs
15862 @subsection Setuid Programs
15864 @cindex setuid programs
15865 Some programs need to run with ``root'' privileges, even when they are
15866 launched by unprivileged users. A notorious example is the
15867 @command{passwd} program, which users can run to change their
15868 password, and which needs to access the @file{/etc/passwd} and
15869 @file{/etc/shadow} files---something normally restricted to root, for
15870 obvious security reasons. To address that, these executables are
15871 @dfn{setuid-root}, meaning that they always run with root privileges
15872 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
15873 for more info about the setuid mechanism.)
15875 The store itself @emph{cannot} contain setuid programs: that would be a
15876 security issue since any user on the system can write derivations that
15877 populate the store (@pxref{The Store}). Thus, a different mechanism is
15878 used: instead of changing the setuid bit directly on files that are in
15879 the store, we let the system administrator @emph{declare} which programs
15880 should be setuid root.
15882 The @code{setuid-programs} field of an @code{operating-system}
15883 declaration contains a list of G-expressions denoting the names of
15884 programs to be setuid-root (@pxref{Using the Configuration System}).
15885 For instance, the @command{passwd} program, which is part of the Shadow
15886 package, can be designated by this G-expression (@pxref{G-Expressions}):
15889 #~(string-append #$shadow "/bin/passwd")
15892 A default set of setuid programs is defined by the
15893 @code{%setuid-programs} variable of the @code{(gnu system)} module.
15895 @defvr {Scheme Variable} %setuid-programs
15896 A list of G-expressions denoting common programs that are setuid-root.
15898 The list includes commands such as @command{passwd}, @command{ping},
15899 @command{su}, and @command{sudo}.
15902 Under the hood, the actual setuid programs are created in the
15903 @file{/run/setuid-programs} directory at system activation time. The
15904 files in this directory refer to the ``real'' binaries, which are in the
15907 @node X.509 Certificates
15908 @subsection X.509 Certificates
15910 @cindex HTTPS, certificates
15911 @cindex X.509 certificates
15913 Web servers available over HTTPS (that is, HTTP over the transport-layer
15914 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
15915 that the client can then use to @emph{authenticate} the server. To do
15916 that, clients verify that the server's certificate is signed by a
15917 so-called @dfn{certificate authority} (CA). But to verify the CA's
15918 signature, clients must have first acquired the CA's certificate.
15920 Web browsers such as GNU@tie{}IceCat include their own set of CA
15921 certificates, such that they are able to verify CA signatures
15924 However, most other programs that can talk HTTPS---@command{wget},
15925 @command{git}, @command{w3m}, etc.---need to be told where CA
15926 certificates can be found.
15928 @cindex @code{nss-certs}
15929 In GuixSD, this is done by adding a package that provides certificates
15930 to the @code{packages} field of the @code{operating-system} declaration
15931 (@pxref{operating-system Reference}). GuixSD includes one such package,
15932 @code{nss-certs}, which is a set of CA certificates provided as part of
15933 Mozilla's Network Security Services.
15935 Note that it is @emph{not} part of @var{%base-packages}, so you need to
15936 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
15937 most applications and libraries look for certificates by default, points
15938 to the certificates installed globally.
15940 Unprivileged users, including users of Guix on a foreign distro,
15941 can also install their own certificate package in
15942 their profile. A number of environment variables need to be defined so
15943 that applications and libraries know where to find them. Namely, the
15944 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
15945 variables. Some applications add their own environment variables; for
15946 instance, the Git version control system honors the certificate bundle
15947 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
15948 would typically run something like:
15951 $ guix package -i nss-certs
15952 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
15953 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
15954 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
15957 As another example, R requires the @code{CURL_CA_BUNDLE} environment
15958 variable to point to a certificate bundle, so you would have to run
15959 something like this:
15962 $ guix package -i nss-certs
15963 $ export CURL_CA_BUNDLE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
15966 For other applications you may want to look up the required environment
15967 variable in the relevant documentation.
15970 @node Name Service Switch
15971 @subsection Name Service Switch
15973 @cindex name service switch
15975 The @code{(gnu system nss)} module provides bindings to the
15976 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
15977 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
15978 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
15979 extended with new ``name'' lookup methods for system databases, which
15980 includes host names, service names, user accounts, and more (@pxref{Name
15981 Service Switch, System Databases and Name Service Switch,, libc, The GNU
15982 C Library Reference Manual}).
15984 The NSS configuration specifies, for each system database, which lookup
15985 method is to be used, and how the various methods are chained
15986 together---for instance, under which circumstances NSS should try the
15987 next method in the list. The NSS configuration is given in the
15988 @code{name-service-switch} field of @code{operating-system} declarations
15989 (@pxref{operating-system Reference, @code{name-service-switch}}).
15992 @cindex .local, host name lookup
15993 As an example, the declaration below configures the NSS to use the
15994 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
15995 back-end}, which supports host name lookups over multicast DNS (mDNS)
15996 for host names ending in @code{.local}:
15999 (name-service-switch
16000 (hosts (list %files ;first, check /etc/hosts
16002 ;; If the above did not succeed, try
16003 ;; with 'mdns_minimal'.
16005 (name "mdns_minimal")
16007 ;; 'mdns_minimal' is authoritative for
16008 ;; '.local'. When it returns "not found",
16009 ;; no need to try the next methods.
16010 (reaction (lookup-specification
16011 (not-found => return))))
16013 ;; Then fall back to DNS.
16017 ;; Finally, try with the "full" 'mdns'.
16022 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
16023 contains this configuration, so you will not have to type it if all you
16024 want is to have @code{.local} host lookup working.
16026 Note that, in this case, in addition to setting the
16027 @code{name-service-switch} of the @code{operating-system} declaration,
16028 you also need to use @code{avahi-service} (@pxref{Networking Services,
16029 @code{avahi-service}}), or @var{%desktop-services}, which includes it
16030 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
16031 to the name service cache daemon (@pxref{Base Services,
16032 @code{nscd-service}}).
16034 For convenience, the following variables provide typical NSS
16037 @defvr {Scheme Variable} %default-nss
16038 This is the default name service switch configuration, a
16039 @code{name-service-switch} object.
16042 @defvr {Scheme Variable} %mdns-host-lookup-nss
16043 This is the name service switch configuration with support for host name
16044 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
16047 The reference for name service switch configuration is given below. It
16048 is a direct mapping of the configuration file format of the C library , so
16049 please refer to the C library manual for more information (@pxref{NSS
16050 Configuration File,,, libc, The GNU C Library Reference Manual}).
16051 Compared to the configuration file format of libc NSS, it has the advantage
16052 not only of adding this warm parenthetic feel that we like, but also
16053 static checks: you will know about syntax errors and typos as soon as you
16054 run @command{guix system}.
16056 @deftp {Data Type} name-service-switch
16058 This is the data type representation the configuration of libc's name
16059 service switch (NSS). Each field below represents one of the supported
16076 The system databases handled by the NSS. Each of these fields must be a
16077 list of @code{<name-service>} objects (see below).
16081 @deftp {Data Type} name-service
16083 This is the data type representing an actual name service and the
16084 associated lookup action.
16088 A string denoting the name service (@pxref{Services in the NSS
16089 configuration,,, libc, The GNU C Library Reference Manual}).
16091 Note that name services listed here must be visible to nscd. This is
16092 achieved by passing the @code{#:name-services} argument to
16093 @code{nscd-service} the list of packages providing the needed name
16094 services (@pxref{Base Services, @code{nscd-service}}).
16097 An action specified using the @code{lookup-specification} macro
16098 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
16099 Reference Manual}). For example:
16102 (lookup-specification (unavailable => continue)
16103 (success => return))
16108 @node Initial RAM Disk
16109 @subsection Initial RAM Disk
16112 @cindex initial RAM disk
16113 For bootstrapping purposes, the Linux-Libre kernel is passed an
16114 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
16115 root file system as well as an initialization script. The latter is
16116 responsible for mounting the real root file system, and for loading any
16117 kernel modules that may be needed to achieve that.
16119 The @code{initrd} field of an @code{operating-system} declaration allows
16120 you to specify which initrd you would like to use. The @code{(gnu
16121 system linux-initrd)} module provides three ways to build an initrd: the
16122 high-level @code{base-initrd} procedure and the low-level
16123 @code{raw-initrd} and @code{expression->initrd} procedures.
16125 The @code{base-initrd} procedure is intended to cover most common uses.
16126 For example, if you want to add a bunch of kernel modules to be loaded
16127 at boot time, you can define the @code{initrd} field of the operating
16128 system declaration like this:
16131 (initrd (lambda (file-systems . rest)
16132 ;; Create a standard initrd that has modules "foo.ko"
16133 ;; and "bar.ko", as well as their dependencies, in
16134 ;; addition to the modules available by default.
16135 (apply base-initrd file-systems
16136 #:extra-modules '("foo" "bar")
16140 The @code{base-initrd} procedure also handles common use cases that
16141 involves using the system as a QEMU guest, or as a ``live'' system with
16142 volatile root file system.
16144 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
16145 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
16146 such as trying to guess which kernel modules and packages should be included
16147 to the initrd. An example use of @code{raw-initrd} is when a user has
16148 a custom Linux kernel configuration and default kernel modules included by
16149 @code{base-initrd} are not available.
16151 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
16152 honors several options passed on the Linux kernel command line
16153 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
16154 @code{-append} option of QEMU), notably:
16157 @item --load=@var{boot}
16158 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
16159 program, once it has mounted the root file system.
16161 GuixSD uses this option to yield control to a boot program that runs the
16162 service activation programs and then spawns the GNU@tie{}Shepherd, the
16163 initialization system.
16165 @item --root=@var{root}
16166 Mount @var{root} as the root file system. @var{root} can be a
16167 device name like @code{/dev/sda1}, a partition label, or a partition
16170 @item --system=@var{system}
16171 Have @file{/run/booted-system} and @file{/run/current-system} point to
16174 @item modprobe.blacklist=@var{modules}@dots{}
16175 @cindex module, black-listing
16176 @cindex black list, of kernel modules
16177 Instruct the initial RAM disk as well as the @command{modprobe} command
16178 (from the kmod package) to refuse to load @var{modules}. @var{modules}
16179 must be a comma-separated list of module names---e.g.,
16180 @code{usbkbd,9pnet}.
16183 Start a read-eval-print loop (REPL) from the initial RAM disk before it
16184 tries to load kernel modules and to mount the root file system. Our
16185 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
16186 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
16187 Manual}, for more information on Guile's REPL.
16191 Now that you know all the features that initial RAM disks produced by
16192 @code{base-initrd} and @code{raw-initrd} provide,
16193 here is how to use it and customize it further.
16196 @cindex initial RAM disk
16197 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
16198 [#:linux-modules '()] [#:mapped-devices '()] @
16199 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
16200 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
16201 a list of file systems to be mounted by the initrd, possibly in addition to
16202 the root file system specified on the kernel command line via @code{--root}.
16203 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
16204 @var{mapped-devices} is a list of device mappings to realize before
16205 @var{file-systems} are mounted (@pxref{Mapped Devices}).
16206 @var{helper-packages} is a list of packages to be copied in the initrd. It may
16207 include @code{e2fsck/static} or other packages needed by the initrd to check
16210 When @var{qemu-networking?} is true, set up networking with the standard QEMU
16211 parameters. When @var{virtio?} is true, load additional modules so that the
16212 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
16214 When @var{volatile-root?} is true, the root file system is writable but any changes
16218 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
16219 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
16220 [#:virtio? #t] [#:extra-modules '()]
16221 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
16222 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
16223 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
16224 also behaves as in @code{raw-initrd}.
16226 When @var{virtio?} is true, load additional modules so that the
16227 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
16229 The initrd is automatically populated with all the kernel modules necessary
16230 for @var{file-systems} and for the given options. However, additional kernel
16231 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
16232 loaded at boot time in the order in which they appear.
16235 Needless to say, the initrds we produce and use embed a
16236 statically-linked Guile, and the initialization program is a Guile
16237 program. That gives a lot of flexibility. The
16238 @code{expression->initrd} procedure builds such an initrd, given the
16239 program to run in that initrd.
16241 @deffn {Monadic Procedure} expression->initrd @var{exp} @
16242 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
16243 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
16244 containing @var{guile} and that evaluates @var{exp}, a G-expression,
16245 upon booting. All the derivations referenced by @var{exp} are
16246 automatically copied to the initrd.
16249 @node Bootloader Configuration
16250 @subsection Bootloader Configuration
16253 @cindex boot loader
16255 The operating system supports multiple bootloaders. The bootloader is
16256 configured using @code{bootloader-configuration} declaration. All the
16257 fields of this structure are bootloader agnostic except for one field,
16258 @code{bootloader} that indicates the bootloader to be configured and
16261 Some of the bootloaders do not honor every field of
16262 @code{bootloader-configuration}. For instance, the extlinux
16263 bootloader does not support themes and thus ignores the @code{theme}
16266 @deftp {Data Type} bootloader-configuration
16267 The type of a bootloader configuration declaration.
16271 @item @code{bootloader}
16272 @cindex EFI, bootloader
16273 @cindex UEFI, bootloader
16274 @cindex BIOS, bootloader
16275 The bootloader to use, as a @code{bootloader} object. For now
16276 @code{grub-bootloader}, @code{grub-efi-bootloader},
16277 @code{extlinux-bootloader} and @code{u-boot-bootloader} are supported.
16278 @code{grub-efi-bootloader} allows to boot on modern systems using the
16279 @dfn{Unified Extensible Firmware Interface} (UEFI).
16281 Available bootloaders are described in @code{(gnu bootloader @dots{})}
16284 @item @code{device}
16285 This is a string denoting the boot device. It must be a device name
16286 understood by the bootloader @command{installer} command, such as
16287 @code{/dev/sda} or @code{(hd0)} (for GRUB, @pxref{Invoking grub-install,,, grub,
16290 @item @code{menu-entries} (default: @code{()})
16291 A possibly empty list of @code{menu-entry} objects (see below), denoting
16292 entries to appear in the bootloader menu, in addition to the current
16293 system entry and the entry pointing to previous system generations.
16296 @item @code{default-entry} (default: @code{0})
16297 The index of the default boot menu entry. Index 0 is for the entry of the
16300 @item @code{timeout} (default: @code{5})
16301 The number of seconds to wait for keyboard input before booting. Set to
16302 0 to boot immediately, and to -1 to wait indefinitely.
16304 @item @code{theme} (default: @var{#f})
16305 The bootloader theme object describing the theme to use. If no theme
16306 is provided, some bootloaders might use a default theme, that's true
16309 @item @code{terminal-outputs} (default: @code{'gfxterm})
16310 The output terminals used for the bootloader boot menu, as a list of
16311 symbols. GRUB accepts the values: @code{console}, @code{serial},
16312 @code{serial_@{0-3@}}, @code{gfxterm}, @code{vga_text},
16313 @code{mda_text}, @code{morse}, and @code{pkmodem}. This field
16314 corresponds to the GRUB variable GRUB_TERMINAL_OUTPUT (@pxref{Simple
16315 configuration,,, grub,GNU GRUB manual}).
16317 @item @code{terminal-inputs} (default: @code{'()})
16318 The input terminals used for the bootloader boot menu, as a list of
16319 symbols. For GRUB, the default is the native platform terminal as
16320 determined at run-time. GRUB accepts the values: @code{console},
16321 @code{serial}, @code{serial_@{0-3@}}, @code{at_keyboard}, and
16322 @code{usb_keyboard}. This field corresponds to the GRUB variable
16323 GRUB_TERMINAL_INPUT (@pxref{Simple configuration,,, grub,GNU GRUB
16326 @item @code{serial-unit} (default: @code{#f})
16327 The serial unit used by the bootloader, as an integer from 0 to 3.
16328 For GRUB it is choosen at run-time; currently GRUB chooses 0, which
16329 corresponds to COM1 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
16331 @item @code{serial-speed} (default: @code{#f})
16332 The speed of the serial interface, as an integer. For GRUB, the
16333 default value is chosen at run-time; currently GRUB chooses
16334 9600@tie{}bps (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
16341 Should you want to list additional boot menu entries @i{via} the
16342 @code{menu-entries} field above, you will need to create them with the
16343 @code{menu-entry} form. For example, imagine you want to be able to
16344 boot another distro (hard to imagine!), you can define a menu entry
16349 (label "The Other Distro")
16350 (linux "/boot/old/vmlinux-2.6.32")
16351 (linux-arguments '("root=/dev/sda2"))
16352 (initrd "/boot/old/initrd"))
16357 @deftp {Data Type} menu-entry
16358 The type of an entry in the bootloader menu.
16363 The label to show in the menu---e.g., @code{"GNU"}.
16366 The Linux kernel image to boot, for example:
16369 (file-append linux-libre "/bzImage")
16372 For GRUB, it is also possible to specify a device explicitly in the
16373 file path using GRUB's device naming convention (@pxref{Naming
16374 convention,,, grub, GNU GRUB manual}), for example:
16377 "(hd0,msdos1)/boot/vmlinuz"
16380 If the device is specified explicitly as above, then the @code{device}
16381 field is ignored entirely.
16383 @item @code{linux-arguments} (default: @code{()})
16384 The list of extra Linux kernel command-line arguments---e.g.,
16385 @code{("console=ttyS0")}.
16387 @item @code{initrd}
16388 A G-Expression or string denoting the file name of the initial RAM disk
16389 to use (@pxref{G-Expressions}).
16390 @item @code{device} (default: @code{#f})
16391 The device where the kernel and initrd are to be found---i.e., for GRUB,
16392 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
16394 This may be a file system label (a string), a file system UUID (a
16395 bytevector, @pxref{File Systems}), or @code{#f}, in which case
16396 the bootloader will search the device containing the file specified by
16397 the @code{linux} field (@pxref{search,,, grub, GNU GRUB manual}). It
16398 must @emph{not} be an OS device name such as @file{/dev/sda1}.
16403 @c FIXME: Write documentation once it's stable.
16404 Fow now only GRUB has theme support. GRUB themes are created using
16405 the @code{grub-theme} form, which is not documented yet.
16407 @defvr {Scheme Variable} %default-theme
16408 This is the default GRUB theme used by the operating system if no
16409 @code{theme} field is specified in @code{bootloader-configuration}
16412 It comes with a fancy background image displaying the GNU and Guix
16417 @node Invoking guix system
16418 @subsection Invoking @code{guix system}
16420 Once you have written an operating system declaration as seen in the
16421 previous section, it can be @dfn{instantiated} using the @command{guix
16422 system} command. The synopsis is:
16425 guix system @var{options}@dots{} @var{action} @var{file}
16428 @var{file} must be the name of a file containing an
16429 @code{operating-system} declaration. @var{action} specifies how the
16430 operating system is instantiated. Currently the following values are
16435 Build the operating system described in @var{file}, activate it, and
16436 switch to it@footnote{This action (and the related actions
16437 @code{switch-generation} and @code{roll-back}) are usable only on
16438 systems already running GuixSD.}.
16440 This effects all the configuration specified in @var{file}: user
16441 accounts, system services, global package list, setuid programs, etc.
16442 The command starts system services specified in @var{file} that are not
16443 currently running; if a service is currently running, it does not
16444 attempt to upgrade it since this would not be possible without stopping it
16447 This command creates a new generation whose number is one greater than
16448 the current generation (as reported by @command{guix system
16449 list-generations}). If that generation already exists, it will be
16450 overwritten. This behavior mirrors that of @command{guix package}
16451 (@pxref{Invoking guix package}).
16453 It also adds a bootloader menu entry for the new OS configuration,
16454 ---unless @option{--no-bootloader} is passed. For GRUB, it moves
16455 entries for older configurations to a submenu, allowing you to choose
16456 an older system generation at boot time should you need it.
16459 @c The paragraph below refers to the problem discussed at
16460 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
16461 It is highly recommended to run @command{guix pull} once before you run
16462 @command{guix system reconfigure} for the first time (@pxref{Invoking
16463 guix pull}). Failing to do that you would see an older version of Guix
16464 once @command{reconfigure} has completed.
16467 @item switch-generation
16468 @cindex generations
16469 Switch to an existing system generation. This action atomically
16470 switches the system profile to the specified system generation. It
16471 also rearranges the system's existing bootloader menu entries. It
16472 makes the menu entry for the specified system generation the default,
16473 and it moves the entries for the other generatiors to a submenu, if
16474 supported by the bootloader being used. The next time the system
16475 boots, it will use the specified system generation.
16477 The bootloader itself is not being reinstalled when using this
16478 command. Thus, the installed bootloader is used with an updated
16479 configuration file.
16481 The target generation can be specified explicitly by its generation
16482 number. For example, the following invocation would switch to system
16486 guix system switch-generation 7
16489 The target generation can also be specified relative to the current
16490 generation with the form @code{+N} or @code{-N}, where @code{+3} means
16491 ``3 generations ahead of the current generation,'' and @code{-1} means
16492 ``1 generation prior to the current generation.'' When specifying a
16493 negative value such as @code{-1}, you must precede it with @code{--} to
16494 prevent it from being parsed as an option. For example:
16497 guix system switch-generation -- -1
16500 Currently, the effect of invoking this action is @emph{only} to switch
16501 the system profile to an existing generation and rearrange the
16502 bootloader menu entries. To actually start using the target system
16503 generation, you must reboot after running this action. In the future,
16504 it will be updated to do the same things as @command{reconfigure},
16505 like activating and deactivating services.
16507 This action will fail if the specified generation does not exist.
16510 @cindex rolling back
16511 Switch to the preceding system generation. The next time the system
16512 boots, it will use the preceding system generation. This is the inverse
16513 of @command{reconfigure}, and it is exactly the same as invoking
16514 @command{switch-generation} with an argument of @code{-1}.
16516 Currently, as with @command{switch-generation}, you must reboot after
16517 running this action to actually start using the preceding system
16521 Build the derivation of the operating system, which includes all the
16522 configuration files and programs needed to boot and run the system.
16523 This action does not actually install anything.
16526 Populate the given directory with all the files necessary to run the
16527 operating system specified in @var{file}. This is useful for first-time
16528 installations of GuixSD. For instance:
16531 guix system init my-os-config.scm /mnt
16534 copies to @file{/mnt} all the store items required by the configuration
16535 specified in @file{my-os-config.scm}. This includes configuration
16536 files, packages, and so on. It also creates other essential files
16537 needed for the system to operate correctly---e.g., the @file{/etc},
16538 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
16540 This command also installs bootloader on the device specified in
16541 @file{my-os-config}, unless the @option{--no-bootloader} option was
16545 @cindex virtual machine
16547 @anchor{guix system vm}
16548 Build a virtual machine that contains the operating system declared in
16549 @var{file}, and return a script to run that virtual machine (VM).
16550 Arguments given to the script are passed to QEMU as in the example
16551 below, which enables networking and requests 1@tie{}GiB of RAM for the
16555 $ /gnu/store/@dots{}-run-vm.sh -m 1024 -net user
16558 The VM shares its store with the host system.
16560 Additional file systems can be shared between the host and the VM using
16561 the @code{--share} and @code{--expose} command-line options: the former
16562 specifies a directory to be shared with write access, while the latter
16563 provides read-only access to the shared directory.
16565 The example below creates a VM in which the user's home directory is
16566 accessible read-only, and where the @file{/exchange} directory is a
16567 read-write mapping of @file{$HOME/tmp} on the host:
16570 guix system vm my-config.scm \
16571 --expose=$HOME --share=$HOME/tmp=/exchange
16574 On GNU/Linux, the default is to boot directly to the kernel; this has
16575 the advantage of requiring only a very tiny root disk image since the
16576 store of the host can then be mounted.
16578 The @code{--full-boot} option forces a complete boot sequence, starting
16579 with the bootloader. This requires more disk space since a root image
16580 containing at least the kernel, initrd, and bootloader data files must
16581 be created. The @code{--image-size} option can be used to specify the
16586 Return a virtual machine or disk image of the operating system declared
16587 in @var{file} that stands alone. By default, @command{guix system}
16588 estimates the size of the image needed to store the system, but you can
16589 use the @option{--image-size} option to specify a value.
16591 You can specify the root file system type by using the
16592 @option{--file-system-type} option. It defaults to @code{ext4}.
16594 When using @code{vm-image}, the returned image is in qcow2 format, which
16595 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
16596 for more information on how to run the image in a virtual machine.
16598 When using @code{disk-image}, a raw disk image is produced; it can be
16599 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
16600 the device corresponding to a USB stick, one can copy the image to it
16601 using the following command:
16604 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
16608 Return a script to run the operating system declared in @var{file}
16609 within a container. Containers are a set of lightweight isolation
16610 mechanisms provided by the kernel Linux-libre. Containers are
16611 substantially less resource-demanding than full virtual machines since
16612 the kernel, shared objects, and other resources can be shared with the
16613 host system; this also means they provide thinner isolation.
16615 Currently, the script must be run as root in order to support more than
16616 a single user and group. The container shares its store with the host
16619 As with the @code{vm} action (@pxref{guix system vm}), additional file
16620 systems to be shared between the host and container can be specified
16621 using the @option{--share} and @option{--expose} options:
16624 guix system container my-config.scm \
16625 --expose=$HOME --share=$HOME/tmp=/exchange
16629 This option requires Linux-libre 3.19 or newer.
16634 @var{options} can contain any of the common build options (@pxref{Common
16635 Build Options}). In addition, @var{options} can contain one of the
16639 @item --system=@var{system}
16640 @itemx -s @var{system}
16641 Attempt to build for @var{system} instead of the host system type.
16642 This works as per @command{guix build} (@pxref{Invoking guix build}).
16646 Return the derivation file name of the given operating system without
16649 @item --file-system-type=@var{type}
16650 @itemx -t @var{type}
16651 For the @code{disk-image} action, create a file system of the given
16652 @var{type} on the image.
16654 When this option is omitted, @command{guix system} uses @code{ext4}.
16656 @cindex ISO-9660 format
16657 @cindex CD image format
16658 @cindex DVD image format
16659 @code{--file-system-type=iso9660} produces an ISO-9660 image, suitable
16660 for burning on CDs and DVDs.
16662 @item --image-size=@var{size}
16663 For the @code{vm-image} and @code{disk-image} actions, create an image
16664 of the given @var{size}. @var{size} may be a number of bytes, or it may
16665 include a unit as a suffix (@pxref{Block size, size specifications,,
16666 coreutils, GNU Coreutils}).
16668 When this option is omitted, @command{guix system} computes an estimate
16669 of the image size as a function of the size of the system declared in
16672 @item --root=@var{file}
16673 @itemx -r @var{file}
16674 Make @var{file} a symlink to the result, and register it as a garbage
16677 @item --on-error=@var{strategy}
16678 Apply @var{strategy} when an error occurs when reading @var{file}.
16679 @var{strategy} may be one of the following:
16682 @item nothing-special
16683 Report the error concisely and exit. This is the default strategy.
16686 Likewise, but also display a backtrace.
16689 Report the error and enter Guile's debugger. From there, you can run
16690 commands such as @code{,bt} to get a backtrace, @code{,locals} to
16691 display local variable values, and more generally inspect the state of the
16692 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
16693 a list of available debugging commands.
16698 All the actions above, except @code{build} and @code{init},
16699 can use KVM support in the Linux-libre kernel. Specifically, if the
16700 machine has hardware virtualization support, the corresponding
16701 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
16702 must exist and be readable and writable by the user and by the
16703 build users of the daemon (@pxref{Build Environment Setup}).
16706 Once you have built, configured, re-configured, and re-re-configured
16707 your GuixSD installation, you may find it useful to list the operating
16708 system generations available on disk---and that you can choose from the
16709 bootloader boot menu:
16713 @item list-generations
16714 List a summary of each generation of the operating system available on
16715 disk, in a human-readable way. This is similar to the
16716 @option{--list-generations} option of @command{guix package}
16717 (@pxref{Invoking guix package}).
16719 Optionally, one can specify a pattern, with the same syntax that is used
16720 in @command{guix package --list-generations}, to restrict the list of
16721 generations displayed. For instance, the following command displays
16722 generations that are up to 10 days old:
16725 $ guix system list-generations 10d
16730 The @command{guix system} command has even more to offer! The following
16731 sub-commands allow you to visualize how your system services relate to
16734 @anchor{system-extension-graph}
16737 @item extension-graph
16738 Emit in Dot/Graphviz format to standard output the @dfn{service
16739 extension graph} of the operating system defined in @var{file}
16740 (@pxref{Service Composition}, for more information on service
16746 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
16749 produces a PDF file showing the extension relations among services.
16751 @anchor{system-shepherd-graph}
16752 @item shepherd-graph
16753 Emit in Dot/Graphviz format to standard output the @dfn{dependency
16754 graph} of shepherd services of the operating system defined in
16755 @var{file}. @xref{Shepherd Services}, for more information and for an
16760 @node Running GuixSD in a VM
16761 @subsection Running GuixSD in a Virtual Machine
16763 @cindex virtual machine
16764 To run GuixSD in a virtual machine (VM), one can either use the
16765 pre-built GuixSD VM image distributed at
16766 @indicateurl{ftp://alpha.gnu.org/guix/guixsd-vm-image-@value{VERSION}.@var{system}.tar.xz}
16767 , or build their own virtual machine image using @command{guix system
16768 vm-image} (@pxref{Invoking guix system}). The returned image is in
16769 qcow2 format, which the @uref{http://qemu.org/, QEMU emulator} can
16773 If you built your own image, you must copy it out of the store
16774 (@pxref{The Store}) and give yourself permission to write to the copy
16775 before you can use it. When invoking QEMU, you must choose a system
16776 emulator that is suitable for your hardware platform. Here is a minimal
16777 QEMU invocation that will boot the result of @command{guix system
16778 vm-image} on x86_64 hardware:
16781 $ qemu-system-x86_64 \
16782 -net user -net nic,model=virtio \
16783 -enable-kvm -m 256 /tmp/qemu-image
16786 Here is what each of these options means:
16789 @item qemu-system-x86_64
16790 This specifies the hardware platform to emulate. This should match the
16794 Enable the unprivileged user-mode network stack. The guest OS can
16795 access the host but not vice versa. This is the simplest way to get the
16798 @item -net nic,model=virtio
16799 You must create a network interface of a given model. If you do not
16800 create a NIC, the boot will fail. Assuming your hardware platform is
16801 x86_64, you can get a list of available NIC models by running
16802 @command{qemu-system-x86_64 -net nic,model=help}.
16805 If your system has hardware virtualization extensions, enabling the
16806 virtual machine support (KVM) of the Linux kernel will make things run
16810 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
16811 which may be insufficient for some operations.
16813 @item /tmp/qemu-image
16814 The file name of the qcow2 image.
16817 The default @command{run-vm.sh} script that is returned by an invocation of
16818 @command{guix system vm} does not add a @command{-net user} flag by default.
16819 To get network access from within the vm add the @code{(dhcp-client-service)}
16820 to your system definition and start the VM using
16821 @command{`guix system vm config.scm` -net user}. An important caveat of using
16822 @command{-net user} for networking is that @command{ping} will not work, because
16823 it uses the ICMP protocol. You'll have to use a different command to check for
16824 network connectivity, for example @command{guix download}.
16826 @subsubsection Connecting Through SSH
16830 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
16831 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
16832 boot unsupervised. It requires you to type some characters to initialize the
16833 randomness generator. In addition you need to forward the SSH port, 22 by
16834 default, to the host. You can do this with
16837 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
16840 To connect to the VM you can run
16843 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
16846 The @command{-p} tells @command{ssh} the port you want to connect to.
16847 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
16848 every time you modify your @command{config.scm} file and the
16849 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
16850 connection to an unknown host every time you connect.
16852 @subsubsection Using @command{virt-viewer} with Spice
16854 As an alternative to the default @command{qemu} graphical client you can
16855 use the @command{remote-viewer} from the @command{virt-viewer} package. To
16856 connect pass the @command{-spice port=5930,disable-ticketing} flag to
16857 @command{qemu}. See previous section for further information on how to do this.
16859 Spice also allows you to do some nice stuff like share your clipboard with your
16860 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
16863 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
16864 -chardev spicevmc,name=vdagent,id=vdagent
16865 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
16866 name=com.redhat.spice.0
16869 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
16871 @node Defining Services
16872 @subsection Defining Services
16874 The previous sections show the available services and how one can combine
16875 them in an @code{operating-system} declaration. But how do we define
16876 them in the first place? And what is a service anyway?
16879 * Service Composition:: The model for composing services.
16880 * Service Types and Services:: Types and services.
16881 * Service Reference:: API reference.
16882 * Shepherd Services:: A particular type of service.
16885 @node Service Composition
16886 @subsubsection Service Composition
16890 Here we define a @dfn{service} as, broadly, something that extends the
16891 functionality of the operating system. Often a service is a process---a
16892 @dfn{daemon}---started when the system boots: a secure shell server, a
16893 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
16894 whose execution can be triggered by another daemon---e.g., an FTP server
16895 started by @command{inetd} or a D-Bus service activated by
16896 @command{dbus-daemon}. Occasionally, a service does not map to a
16897 daemon. For instance, the ``account'' service collects user accounts
16898 and makes sure they exist when the system runs; the ``udev'' service
16899 collects device management rules and makes them available to the eudev
16900 daemon; the @file{/etc} service populates the @file{/etc} directory
16903 @cindex service extensions
16904 GuixSD services are connected by @dfn{extensions}. For instance, the
16905 secure shell service @emph{extends} the Shepherd---the GuixSD
16906 initialization system, running as PID@tie{}1---by giving it the command
16907 lines to start and stop the secure shell daemon (@pxref{Networking
16908 Services, @code{lsh-service}}); the UPower service extends the D-Bus
16909 service by passing it its @file{.service} specification, and extends the
16910 udev service by passing it device management rules (@pxref{Desktop
16911 Services, @code{upower-service}}); the Guix daemon service extends the
16912 Shepherd by passing it the command lines to start and stop the daemon,
16913 and extends the account service by passing it a list of required build
16914 user accounts (@pxref{Base Services}).
16916 All in all, services and their ``extends'' relations form a directed
16917 acyclic graph (DAG). If we represent services as boxes and extensions
16918 as arrows, a typical system might provide something like this:
16920 @image{images/service-graph,,5in,Typical service extension graph.}
16922 @cindex system service
16923 At the bottom, we see the @dfn{system service}, which produces the
16924 directory containing everything to run and boot the system, as returned
16925 by the @command{guix system build} command. @xref{Service Reference},
16926 to learn about the other service types shown here.
16927 @xref{system-extension-graph, the @command{guix system extension-graph}
16928 command}, for information on how to generate this representation for a
16929 particular operating system definition.
16931 @cindex service types
16932 Technically, developers can define @dfn{service types} to express these
16933 relations. There can be any number of services of a given type on the
16934 system---for instance, a system running two instances of the GNU secure
16935 shell server (lsh) has two instances of @var{lsh-service-type}, with
16936 different parameters.
16938 The following section describes the programming interface for service
16939 types and services.
16941 @node Service Types and Services
16942 @subsubsection Service Types and Services
16944 A @dfn{service type} is a node in the DAG described above. Let us start
16945 with a simple example, the service type for the Guix build daemon
16946 (@pxref{Invoking guix-daemon}):
16949 (define guix-service-type
16953 (list (service-extension shepherd-root-service-type guix-shepherd-service)
16954 (service-extension account-service-type guix-accounts)
16955 (service-extension activation-service-type guix-activation)))
16956 (default-value (guix-configuration))))
16960 It defines three things:
16964 A name, whose sole purpose is to make inspection and debugging easier.
16967 A list of @dfn{service extensions}, where each extension designates the
16968 target service type and a procedure that, given the parameters of the
16969 service, returns a list of objects to extend the service of that type.
16971 Every service type has at least one service extension. The only
16972 exception is the @dfn{boot service type}, which is the ultimate service.
16975 Optionally, a default value for instances of this type.
16978 In this example, @var{guix-service-type} extends three services:
16981 @item shepherd-root-service-type
16982 The @var{guix-shepherd-service} procedure defines how the Shepherd
16983 service is extended. Namely, it returns a @code{<shepherd-service>}
16984 object that defines how @command{guix-daemon} is started and stopped
16985 (@pxref{Shepherd Services}).
16987 @item account-service-type
16988 This extension for this service is computed by @var{guix-accounts},
16989 which returns a list of @code{user-group} and @code{user-account}
16990 objects representing the build user accounts (@pxref{Invoking
16993 @item activation-service-type
16994 Here @var{guix-activation} is a procedure that returns a gexp, which is
16995 a code snippet to run at ``activation time''---e.g., when the service is
16999 A service of this type is instantiated like this:
17002 (service guix-service-type
17003 (guix-configuration
17005 (use-substitutes? #f)))
17008 The second argument to the @code{service} form is a value representing
17009 the parameters of this specific service instance.
17010 @xref{guix-configuration-type, @code{guix-configuration}}, for
17011 information about the @code{guix-configuration} data type. When the
17012 value is omitted, the default value specified by
17013 @code{guix-service-type} is used:
17016 (service guix-service-type)
17019 @var{guix-service-type} is quite simple because it extends other
17020 services but is not extensible itself.
17022 @c @subsubsubsection Extensible Service Types
17024 The service type for an @emph{extensible} service looks like this:
17027 (define udev-service-type
17028 (service-type (name 'udev)
17030 (list (service-extension shepherd-root-service-type
17031 udev-shepherd-service)))
17033 (compose concatenate) ;concatenate the list of rules
17034 (extend (lambda (config rules)
17036 (($ <udev-configuration> udev initial-rules)
17037 (udev-configuration
17038 (udev udev) ;the udev package to use
17039 (rules (append initial-rules rules)))))))))
17042 This is the service type for the
17043 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
17044 management daemon}. Compared to the previous example, in addition to an
17045 extension of @var{shepherd-root-service-type}, we see two new fields:
17049 This is the procedure to @dfn{compose} the list of extensions to
17050 services of this type.
17052 Services can extend the udev service by passing it lists of rules; we
17053 compose those extensions simply by concatenating them.
17056 This procedure defines how the value of the service is @dfn{extended} with
17057 the composition of the extensions.
17059 Udev extensions are composed into a list of rules, but the udev service
17060 value is itself a @code{<udev-configuration>} record. So here, we
17061 extend that record by appending the list of rules it contains to the
17062 list of contributed rules.
17065 There can be only one instance of an extensible service type such as
17066 @var{udev-service-type}. If there were more, the
17067 @code{service-extension} specifications would be ambiguous.
17069 Still here? The next section provides a reference of the programming
17070 interface for services.
17072 @node Service Reference
17073 @subsubsection Service Reference
17075 We have seen an overview of service types (@pxref{Service Types and
17076 Services}). This section provides a reference on how to manipulate
17077 services and service types. This interface is provided by the
17078 @code{(gnu services)} module.
17080 @deffn {Scheme Procedure} service @var{type} [@var{value}]
17081 Return a new service of @var{type}, a @code{<service-type>} object (see
17082 below.) @var{value} can be any object; it represents the parameters of
17083 this particular service instance.
17085 When @var{value} is omitted, the default value specified by @var{type}
17086 is used; if @var{type} does not specify a default value, an error is
17089 For instance, this:
17092 (service openssh-service-type)
17096 is equivalent to this:
17099 (service openssh-service-type
17100 (openssh-configuration))
17103 In both cases the result is an instance of @code{openssh-service-type}
17104 with the default configuration.
17107 @deffn {Scheme Procedure} service? @var{obj}
17108 Return true if @var{obj} is a service.
17111 @deffn {Scheme Procedure} service-kind @var{service}
17112 Return the type of @var{service}---i.e., a @code{<service-type>} object.
17115 @deffn {Scheme Procedure} service-value @var{service}
17116 Return the value associated with @var{service}. It represents its
17120 Here is an example of how a service is created and manipulated:
17124 (service nginx-service-type
17125 (nginx-configuration
17127 (log-directory log-directory)
17128 (run-directory run-directory)
17129 (file config-file))))
17134 (eq? (service-kind s) nginx-service-type)
17138 The @code{modify-services} form provides a handy way to change the
17139 parameters of some of the services of a list such as
17140 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
17141 evaluates to a list of services. Of course, you could always use
17142 standard list combinators such as @code{map} and @code{fold} to do that
17143 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
17144 @code{modify-services} simply provides a more concise form for this
17147 @deffn {Scheme Syntax} modify-services @var{services} @
17148 (@var{type} @var{variable} => @var{body}) @dots{}
17150 Modify the services listed in @var{services} according to the given
17151 clauses. Each clause has the form:
17154 (@var{type} @var{variable} => @var{body})
17157 where @var{type} is a service type---e.g.,
17158 @code{guix-service-type}---and @var{variable} is an identifier that is
17159 bound within the @var{body} to the service parameters---e.g., a
17160 @code{guix-configuration} instance---of the original service of that
17163 The @var{body} should evaluate to the new service parameters, which will
17164 be used to configure the new service. This new service will replace the
17165 original in the resulting list. Because a service's service parameters
17166 are created using @code{define-record-type*}, you can write a succinct
17167 @var{body} that evaluates to the new service parameters by using the
17168 @code{inherit} feature that @code{define-record-type*} provides.
17170 @xref{Using the Configuration System}, for example usage.
17174 Next comes the programming interface for service types. This is
17175 something you want to know when writing new service definitions, but not
17176 necessarily when simply looking for ways to customize your
17177 @code{operating-system} declaration.
17179 @deftp {Data Type} service-type
17180 @cindex service type
17181 This is the representation of a @dfn{service type} (@pxref{Service Types
17186 This is a symbol, used only to simplify inspection and debugging.
17188 @item @code{extensions}
17189 A non-empty list of @code{<service-extension>} objects (see below).
17191 @item @code{compose} (default: @code{#f})
17192 If this is @code{#f}, then the service type denotes services that cannot
17193 be extended---i.e., services that do not receive ``values'' from other
17196 Otherwise, it must be a one-argument procedure. The procedure is called
17197 by @code{fold-services} and is passed a list of values collected from
17198 extensions. It must return a value that is a valid parameter value for
17199 the service instance.
17201 @item @code{extend} (default: @code{#f})
17202 If this is @code{#f}, services of this type cannot be extended.
17204 Otherwise, it must be a two-argument procedure: @code{fold-services}
17205 calls it, passing it the initial value of the service as the first argument
17206 and the result of applying @code{compose} to the extension values as the
17210 @xref{Service Types and Services}, for examples.
17213 @deffn {Scheme Procedure} service-extension @var{target-type} @
17215 Return a new extension for services of type @var{target-type}.
17216 @var{compute} must be a one-argument procedure: @code{fold-services}
17217 calls it, passing it the value associated with the service that provides
17218 the extension; it must return a valid value for the target service.
17221 @deffn {Scheme Procedure} service-extension? @var{obj}
17222 Return true if @var{obj} is a service extension.
17225 Occasionally, you might want to simply extend an existing service. This
17226 involves creating a new service type and specifying the extension of
17227 interest, which can be verbose; the @code{simple-service} procedure
17228 provides a shorthand for this.
17230 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
17231 Return a service that extends @var{target} with @var{value}. This works
17232 by creating a singleton service type @var{name}, of which the returned
17233 service is an instance.
17235 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
17239 (simple-service 'my-mcron-job mcron-service-type
17240 #~(job '(next-hour (3)) "guix gc -F 2G"))
17244 At the core of the service abstraction lies the @code{fold-services}
17245 procedure, which is responsible for ``compiling'' a list of services
17246 down to a single directory that contains everything needed to boot and
17247 run the system---the directory shown by the @command{guix system build}
17248 command (@pxref{Invoking guix system}). In essence, it propagates
17249 service extensions down the service graph, updating each node parameters
17250 on the way, until it reaches the root node.
17252 @deffn {Scheme Procedure} fold-services @var{services} @
17253 [#:target-type @var{system-service-type}]
17254 Fold @var{services} by propagating their extensions down to the root of
17255 type @var{target-type}; return the root service adjusted accordingly.
17258 Lastly, the @code{(gnu services)} module also defines several essential
17259 service types, some of which are listed below.
17261 @defvr {Scheme Variable} system-service-type
17262 This is the root of the service graph. It produces the system directory
17263 as returned by the @command{guix system build} command.
17266 @defvr {Scheme Variable} boot-service-type
17267 The type of the ``boot service'', which produces the @dfn{boot script}.
17268 The boot script is what the initial RAM disk runs when booting.
17271 @defvr {Scheme Variable} etc-service-type
17272 The type of the @file{/etc} service. This service can be extended by
17273 passing it name/file tuples such as:
17276 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
17279 In this example, the effect would be to add an @file{/etc/issue} file
17280 pointing to the given file.
17283 @defvr {Scheme Variable} setuid-program-service-type
17284 Type for the ``setuid-program service''. This service collects lists of
17285 executable file names, passed as gexps, and adds them to the set of
17286 setuid-root programs on the system (@pxref{Setuid Programs}).
17289 @defvr {Scheme Variable} profile-service-type
17290 Type of the service that populates the @dfn{system profile}---i.e., the
17291 programs under @file{/run/current-system/profile}. Other services can
17292 extend it by passing it lists of packages to add to the system profile.
17296 @node Shepherd Services
17297 @subsubsection Shepherd Services
17299 @cindex shepherd services
17301 @cindex init system
17302 The @code{(gnu services shepherd)} module provides a way to define
17303 services managed by the GNU@tie{}Shepherd, which is the GuixSD
17304 initialization system---the first process that is started when the
17305 system boots, also known as PID@tie{}1
17306 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
17308 Services in the Shepherd can depend on each other. For instance, the
17309 SSH daemon may need to be started after the syslog daemon has been
17310 started, which in turn can only happen once all the file systems have
17311 been mounted. The simple operating system defined earlier (@pxref{Using
17312 the Configuration System}) results in a service graph like this:
17314 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
17316 You can actually generate such a graph for any operating system
17317 definition using the @command{guix system shepherd-graph} command
17318 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
17320 The @var{%shepherd-root-service} is a service object representing
17321 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
17322 by passing it lists of @code{<shepherd-service>} objects.
17324 @deftp {Data Type} shepherd-service
17325 The data type representing a service managed by the Shepherd.
17328 @item @code{provision}
17329 This is a list of symbols denoting what the service provides.
17331 These are the names that may be passed to @command{herd start},
17332 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
17333 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
17334 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
17336 @item @code{requirements} (default: @code{'()})
17337 List of symbols denoting the Shepherd services this one depends on.
17339 @item @code{respawn?} (default: @code{#t})
17340 Whether to restart the service when it stops, for instance when the
17341 underlying process dies.
17344 @itemx @code{stop} (default: @code{#~(const #f)})
17345 The @code{start} and @code{stop} fields refer to the Shepherd's
17346 facilities to start and stop processes (@pxref{Service De- and
17347 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
17348 G-expressions that get expanded in the Shepherd configuration file
17349 (@pxref{G-Expressions}).
17351 @item @code{documentation}
17352 A documentation string, as shown when running:
17355 herd doc @var{service-name}
17358 where @var{service-name} is one of the symbols in @var{provision}
17359 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
17361 @item @code{modules} (default: @var{%default-modules})
17362 This is the list of modules that must be in scope when @code{start} and
17363 @code{stop} are evaluated.
17368 @defvr {Scheme Variable} shepherd-root-service-type
17369 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
17371 This is the service type that extensions target when they want to create
17372 shepherd services (@pxref{Service Types and Services}, for an example).
17373 Each extension must pass a list of @code{<shepherd-service>}.
17376 @defvr {Scheme Variable} %shepherd-root-service
17377 This service represents PID@tie{}1.
17381 @node Documentation
17382 @section Documentation
17384 @cindex documentation, searching for
17385 @cindex searching for documentation
17386 @cindex Info, documentation format
17388 @cindex manual pages
17389 In most cases packages installed with Guix come with documentation.
17390 There are two main documentation formats: ``Info'', a browseable
17391 hypertext format used for GNU software, and ``manual pages'' (or ``man
17392 pages''), the linear documentation format traditionally found on Unix.
17393 Info manuals are accessed with the @command{info} command or with Emacs,
17394 and man pages are accessed using @command{man}.
17396 You can look for documentation of software installed on your system by
17397 keyword. For example, the following command searches for information
17398 about ``TLS'' in Info manuals:
17402 "(emacs)Network Security" -- STARTTLS
17403 "(emacs)Network Security" -- TLS
17404 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
17405 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
17410 The command below searches for the same keyword in man pages:
17414 SSL (7) - OpenSSL SSL/TLS library
17415 certtool (1) - GnuTLS certificate tool
17419 These searches are purely local to your computer so you have the
17420 guarantee that documentation you find corresponds to what you have
17421 actually installed, you can access it off-line, and your privacy is
17424 Once you have these results, you can view the relevant documentation by
17428 $ info "(gnutls)Core TLS API"
17438 Info manuals contain sections and indices as well as hyperlinks like
17439 those found in Web pages. The @command{info} reader (@pxref{Top, Info
17440 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
17441 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
17442 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
17443 Introduction}, for an introduction to Info navigation.
17445 @node Installing Debugging Files
17446 @section Installing Debugging Files
17448 @cindex debugging files
17449 Program binaries, as produced by the GCC compilers for instance, are
17450 typically written in the ELF format, with a section containing
17451 @dfn{debugging information}. Debugging information is what allows the
17452 debugger, GDB, to map binary code to source code; it is required to
17453 debug a compiled program in good conditions.
17455 The problem with debugging information is that is takes up a fair amount
17456 of disk space. For example, debugging information for the GNU C Library
17457 weighs in at more than 60 MiB. Thus, as a user, keeping all the
17458 debugging info of all the installed programs is usually not an option.
17459 Yet, space savings should not come at the cost of an impediment to
17460 debugging---especially in the GNU system, which should make it easier
17461 for users to exert their computing freedom (@pxref{GNU Distribution}).
17463 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
17464 mechanism that allows users to get the best of both worlds: debugging
17465 information can be stripped from the binaries and stored in separate
17466 files. GDB is then able to load debugging information from those files,
17467 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
17470 The GNU distribution takes advantage of this by storing debugging
17471 information in the @code{lib/debug} sub-directory of a separate package
17472 output unimaginatively called @code{debug} (@pxref{Packages with
17473 Multiple Outputs}). Users can choose to install the @code{debug} output
17474 of a package when they need it. For instance, the following command
17475 installs the debugging information for the GNU C Library and for GNU
17479 guix package -i glibc:debug guile:debug
17482 GDB must then be told to look for debug files in the user's profile, by
17483 setting the @code{debug-file-directory} variable (consider setting it
17484 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
17488 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
17491 From there on, GDB will pick up debugging information from the
17492 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
17494 In addition, you will most likely want GDB to be able to show the source
17495 code being debugged. To do that, you will have to unpack the source
17496 code of the package of interest (obtained with @code{guix build
17497 --source}, @pxref{Invoking guix build}), and to point GDB to that source
17498 directory using the @code{directory} command (@pxref{Source Path,
17499 @code{directory},, gdb, Debugging with GDB}).
17501 @c XXX: keep me up-to-date
17502 The @code{debug} output mechanism in Guix is implemented by the
17503 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
17504 opt-in---debugging information is available only for the packages
17505 with definitions explicitly declaring a @code{debug} output. This may be
17506 changed to opt-out in the future if our build farm servers can handle
17507 the load. To check whether a package has a @code{debug} output, use
17508 @command{guix package --list-available} (@pxref{Invoking guix package}).
17511 @node Security Updates
17512 @section Security Updates
17514 @cindex security updates
17515 @cindex security vulnerabilities
17516 Occasionally, important security vulnerabilities are discovered in software
17517 packages and must be patched. Guix developers try hard to keep track of
17518 known vulnerabilities and to apply fixes as soon as possible in the
17519 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
17520 containing only security updates.) The @command{guix lint} tool helps
17521 developers find out about vulnerable versions of software packages in the
17526 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
17527 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
17528 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
17532 @xref{Invoking guix lint}, for more information.
17535 As of version @value{VERSION}, the feature described below is considered
17539 Guix follows a functional
17540 package management discipline (@pxref{Introduction}), which implies
17541 that, when a package is changed, @emph{every package that depends on it}
17542 must be rebuilt. This can significantly slow down the deployment of
17543 fixes in core packages such as libc or Bash, since basically the whole
17544 distribution would need to be rebuilt. Using pre-built binaries helps
17545 (@pxref{Substitutes}), but deployment may still take more time than
17549 To address this, Guix implements @dfn{grafts}, a mechanism that allows
17550 for fast deployment of critical updates without the costs associated
17551 with a whole-distribution rebuild. The idea is to rebuild only the
17552 package that needs to be patched, and then to ``graft'' it onto packages
17553 explicitly installed by the user and that were previously referring to
17554 the original package. The cost of grafting is typically very low, and
17555 order of magnitudes lower than a full rebuild of the dependency chain.
17557 @cindex replacements of packages, for grafts
17558 For instance, suppose a security update needs to be applied to Bash.
17559 Guix developers will provide a package definition for the ``fixed''
17560 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
17561 Packages}). Then, the original package definition is augmented with a
17562 @code{replacement} field pointing to the package containing the bug fix:
17569 (replacement bash-fixed)))
17572 From there on, any package depending directly or indirectly on Bash---as
17573 reported by @command{guix gc --requisites} (@pxref{Invoking guix
17574 gc})---that is installed is automatically ``rewritten'' to refer to
17575 @var{bash-fixed} instead of @var{bash}. This grafting process takes
17576 time proportional to the size of the package, usually less than a
17577 minute for an ``average'' package on a recent machine. Grafting is
17578 recursive: when an indirect dependency requires grafting, then grafting
17579 ``propagates'' up to the package that the user is installing.
17581 Currently, the length of the name and version of the graft and that of
17582 the package it replaces (@var{bash-fixed} and @var{bash} in the example
17583 above) must be equal. This restriction mostly comes from the fact that
17584 grafting works by patching files, including binary files, directly.
17585 Other restrictions may apply: for instance, when adding a graft to a
17586 package providing a shared library, the original shared library and its
17587 replacement must have the same @code{SONAME} and be binary-compatible.
17589 The @option{--no-grafts} command-line option allows you to forcefully
17590 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
17594 guix build bash --no-grafts
17598 returns the store file name of the original Bash, whereas:
17605 returns the store file name of the ``fixed'', replacement Bash. This
17606 allows you to distinguish between the two variants of Bash.
17608 To verify which Bash your whole profile refers to, you can run
17609 (@pxref{Invoking guix gc}):
17612 guix gc -R `readlink -f ~/.guix-profile` | grep bash
17616 @dots{} and compare the store file names that you get with those above.
17617 Likewise for a complete GuixSD system generation:
17620 guix gc -R `guix system build my-config.scm` | grep bash
17623 Lastly, to check which Bash running processes are using, you can use the
17624 @command{lsof} command:
17627 lsof | grep /gnu/store/.*bash
17631 @node Package Modules
17632 @section Package Modules
17634 From a programming viewpoint, the package definitions of the
17635 GNU distribution are provided by Guile modules in the @code{(gnu packages
17636 @dots{})} name space@footnote{Note that packages under the @code{(gnu
17637 packages @dots{})} module name space are not necessarily ``GNU
17638 packages''. This module naming scheme follows the usual Guile module
17639 naming convention: @code{gnu} means that these modules are distributed
17640 as part of the GNU system, and @code{packages} identifies modules that
17641 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
17642 Reference Manual}). For instance, the @code{(gnu packages emacs)}
17643 module exports a variable named @code{emacs}, which is bound to a
17644 @code{<package>} object (@pxref{Defining Packages}).
17646 The @code{(gnu packages @dots{})} module name space is
17647 automatically scanned for packages by the command-line tools. For
17648 instance, when running @code{guix package -i emacs}, all the @code{(gnu
17649 packages @dots{})} modules are scanned until one that exports a package
17650 object whose name is @code{emacs} is found. This package search
17651 facility is implemented in the @code{(gnu packages)} module.
17653 @cindex customization, of packages
17654 @cindex package module search path
17655 Users can store package definitions in modules with different
17656 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
17657 name and module name must match. For instance, the @code{(my-packages
17658 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
17659 relative to the load path specified with @option{--load-path} or
17660 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
17661 guile, GNU Guile Reference Manual}, for details.}. These package definitions
17662 will not be visible by default. Users can invoke commands such as
17663 @command{guix package} and @command{guix build} with the
17664 @code{-e} option so that they know where to find the package. Better
17665 yet, they can use the
17666 @code{-L} option of these commands to make those modules visible
17667 (@pxref{Invoking guix build, @code{--load-path}}), or define the
17668 @code{GUIX_PACKAGE_PATH} environment variable. This environment
17669 variable makes it easy to extend or customize the distribution and is
17670 honored by all the user interfaces.
17672 @defvr {Environment Variable} GUIX_PACKAGE_PATH
17673 This is a colon-separated list of directories to search for additional
17674 package modules. Directories listed in this variable take precedence
17675 over the own modules of the distribution.
17678 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
17679 each package is built based solely on other packages in the
17680 distribution. The root of this dependency graph is a small set of
17681 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
17682 bootstrap)} module. For more information on bootstrapping,
17683 @pxref{Bootstrapping}.
17685 @node Packaging Guidelines
17686 @section Packaging Guidelines
17688 @cindex packages, creating
17689 The GNU distribution is nascent and may well lack some of your favorite
17690 packages. This section describes how you can help make the distribution
17691 grow. @xref{Contributing}, for additional information on how you can
17694 Free software packages are usually distributed in the form of
17695 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
17696 all the source files. Adding a package to the distribution means
17697 essentially two things: adding a @dfn{recipe} that describes how to
17698 build the package, including a list of other packages required to build
17699 it, and adding @dfn{package metadata} along with that recipe, such as a
17700 description and licensing information.
17702 In Guix all this information is embodied in @dfn{package definitions}.
17703 Package definitions provide a high-level view of the package. They are
17704 written using the syntax of the Scheme programming language; in fact,
17705 for each package we define a variable bound to the package definition,
17706 and export that variable from a module (@pxref{Package Modules}).
17707 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
17708 creating packages. For more information on package definitions,
17709 @pxref{Defining Packages}.
17711 Once a package definition is in place, stored in a file in the Guix
17712 source tree, it can be tested using the @command{guix build} command
17713 (@pxref{Invoking guix build}). For example, assuming the new package is
17714 called @code{gnew}, you may run this command from the Guix build tree
17715 (@pxref{Running Guix Before It Is Installed}):
17718 ./pre-inst-env guix build gnew --keep-failed
17721 Using @code{--keep-failed} makes it easier to debug build failures since
17722 it provides access to the failed build tree. Another useful
17723 command-line option when debugging is @code{--log-file}, to access the
17726 If the package is unknown to the @command{guix} command, it may be that
17727 the source file contains a syntax error, or lacks a @code{define-public}
17728 clause to export the package variable. To figure it out, you may load
17729 the module from Guile to get more information about the actual error:
17732 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
17735 Once your package builds correctly, please send us a patch
17736 (@pxref{Contributing}). Well, if you need help, we will be happy to
17737 help you too. Once the patch is committed in the Guix repository, the
17738 new package automatically gets built on the supported platforms by
17739 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
17742 @cindex substituter
17743 Users can obtain the new package definition simply by running
17744 @command{guix pull} (@pxref{Invoking guix pull}). When
17745 @code{hydra.gnu.org} is done building the package, installing the
17746 package automatically downloads binaries from there
17747 (@pxref{Substitutes}). The only place where human intervention is
17748 needed is to review and apply the patch.
17752 * Software Freedom:: What may go into the distribution.
17753 * Package Naming:: What's in a name?
17754 * Version Numbers:: When the name is not enough.
17755 * Synopses and Descriptions:: Helping users find the right package.
17756 * Python Modules:: A touch of British comedy.
17757 * Perl Modules:: Little pearls.
17758 * Java Packages:: Coffee break.
17759 * Fonts:: Fond of fonts.
17762 @node Software Freedom
17763 @subsection Software Freedom
17765 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
17766 @cindex free software
17767 The GNU operating system has been developed so that users can have
17768 freedom in their computing. GNU is @dfn{free software}, meaning that
17769 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
17770 essential freedoms}: to run the program, to study and change the program
17771 in source code form, to redistribute exact copies, and to distribute
17772 modified versions. Packages found in the GNU distribution provide only
17773 software that conveys these four freedoms.
17775 In addition, the GNU distribution follow the
17776 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
17777 software distribution guidelines}. Among other things, these guidelines
17778 reject non-free firmware, recommendations of non-free software, and
17779 discuss ways to deal with trademarks and patents.
17781 Some otherwise free upstream package sources contain a small and optional
17782 subset that violates the above guidelines, for instance because this subset
17783 is itself non-free code. When that happens, the offending items are removed
17784 with appropriate patches or code snippets in the @code{origin} form of the
17785 package (@pxref{Defining Packages}). This way, @code{guix
17786 build --source} returns the ``freed'' source rather than the unmodified
17790 @node Package Naming
17791 @subsection Package Naming
17793 @cindex package name
17794 A package has actually two names associated with it:
17795 First, there is the name of the @emph{Scheme variable}, the one following
17796 @code{define-public}. By this name, the package can be made known in the
17797 Scheme code, for instance as input to another package. Second, there is
17798 the string in the @code{name} field of a package definition. This name
17799 is used by package management commands such as
17800 @command{guix package} and @command{guix build}.
17802 Both are usually the same and correspond to the lowercase conversion of
17803 the project name chosen upstream, with underscores replaced with
17804 hyphens. For instance, GNUnet is available as @code{gnunet}, and
17805 SDL_net as @code{sdl-net}.
17807 We do not add @code{lib} prefixes for library packages, unless these are
17808 already part of the official project name. But @pxref{Python
17809 Modules} and @ref{Perl Modules} for special rules concerning modules for
17810 the Python and Perl languages.
17812 Font package names are handled differently, @pxref{Fonts}.
17815 @node Version Numbers
17816 @subsection Version Numbers
17818 @cindex package version
17819 We usually package only the latest version of a given free software
17820 project. But sometimes, for instance for incompatible library versions,
17821 two (or more) versions of the same package are needed. These require
17822 different Scheme variable names. We use the name as defined
17823 in @ref{Package Naming}
17824 for the most recent version; previous versions use the same name, suffixed
17825 by @code{-} and the smallest prefix of the version number that may
17826 distinguish the two versions.
17828 The name inside the package definition is the same for all versions of a
17829 package and does not contain any version number.
17831 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
17834 (define-public gtk+
17839 (define-public gtk+-2
17842 (version "2.24.20")
17845 If we also wanted GTK+ 3.8.2, this would be packaged as
17847 (define-public gtk+-3.8
17854 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
17855 @c for a discussion of what follows.
17856 @cindex version number, for VCS snapshots
17857 Occasionally, we package snapshots of upstream's version control system
17858 (VCS) instead of formal releases. This should remain exceptional,
17859 because it is up to upstream developers to clarify what the stable
17860 release is. Yet, it is sometimes necessary. So, what should we put in
17861 the @code{version} field?
17863 Clearly, we need to make the commit identifier of the VCS snapshot
17864 visible in the version string, but we also need to make sure that the
17865 version string is monotonically increasing so that @command{guix package
17866 --upgrade} can determine which version is newer. Since commit
17867 identifiers, notably with Git, are not monotonically increasing, we add
17868 a revision number that we increase each time we upgrade to a newer
17869 snapshot. The resulting version string looks like this:
17874 | | `-- upstream commit ID
17876 | `--- Guix package revision
17878 latest upstream version
17881 It is a good idea to strip commit identifiers in the @code{version}
17882 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
17883 aesthetics have a role to play here) as well as problems related to OS
17884 limits such as the maximum shebang length (127 bytes for the Linux
17885 kernel.) It is best to use the full commit identifiers in
17886 @code{origin}s, though, to avoid ambiguities. A typical package
17887 definition may look like this:
17891 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
17892 (revision "1")) ;Guix package revision
17894 (version (string-append "0.9-" revision "."
17895 (string-take commit 7)))
17898 (uri (git-reference
17899 (url "git://example.org/my-package.git")
17901 (sha256 (base32 "1mbikn@dots{}"))
17902 (file-name (string-append "my-package-" version
17908 @node Synopses and Descriptions
17909 @subsection Synopses and Descriptions
17911 @cindex package description
17912 @cindex package synopsis
17913 As we have seen before, each package in GNU@tie{}Guix includes a
17914 synopsis and a description (@pxref{Defining Packages}). Synopses and
17915 descriptions are important: They are what @command{guix package
17916 --search} searches, and a crucial piece of information to help users
17917 determine whether a given package suits their needs. Consequently,
17918 packagers should pay attention to what goes into them.
17920 Synopses must start with a capital letter and must not end with a
17921 period. They must not start with ``a'' or ``the'', which usually does
17922 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
17923 tool that frobs files''. The synopsis should say what the package
17924 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
17925 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
17926 matching a pattern''.
17928 Keep in mind that the synopsis must be meaningful for a very wide
17929 audience. For example, ``Manipulate alignments in the SAM format''
17930 might make sense for a seasoned bioinformatics researcher, but might be
17931 fairly unhelpful or even misleading to a non-specialized audience. It
17932 is a good idea to come up with a synopsis that gives an idea of the
17933 application domain of the package. In this example, this might give
17934 something like ``Manipulate nucleotide sequence alignments'', which
17935 hopefully gives the user a better idea of whether this is what they are
17938 Descriptions should take between five and ten lines. Use full
17939 sentences, and avoid using acronyms without first introducing them.
17940 Please avoid marketing phrases such as ``world-leading'',
17941 ``industrial-strength'', and ``next-generation'', and avoid superlatives
17942 like ``the most advanced''---they are not helpful to users looking for a
17943 package and may even sound suspicious. Instead, try to be factual,
17944 mentioning use cases and features.
17946 @cindex Texinfo markup, in package descriptions
17947 Descriptions can include Texinfo markup, which is useful to introduce
17948 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
17949 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
17950 should be careful when using some characters for example @samp{@@} and
17951 curly braces which are the basic special characters in Texinfo
17952 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
17953 such as @command{guix package --show} take care of rendering it
17956 Synopses and descriptions are translated by volunteers
17957 @uref{http://translationproject.org/domain/guix-packages.html, at the
17958 Translation Project} so that as many users as possible can read them in
17959 their native language. User interfaces search them and display them in
17960 the language specified by the current locale.
17962 Translation is a lot of work so, as a packager, please pay even more
17963 attention to your synopses and descriptions as every change may entail
17964 additional work for translators. In order to help them, it is possible
17965 to make recommendations or instructions visible to them by inserting
17966 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
17970 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
17971 (description "ARandR is designed to provide a simple visual front end
17972 for the X11 resize-and-rotate (RandR) extension. @dots{}")
17976 @node Python Modules
17977 @subsection Python Modules
17980 We currently package Python 2 and Python 3, under the Scheme variable names
17981 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
17982 To avoid confusion and naming clashes with other programming languages, it
17983 seems desirable that the name of a package for a Python module contains
17984 the word @code{python}.
17986 Some modules are compatible with only one version of Python, others with both.
17987 If the package Foo compiles only with Python 3, we name it
17988 @code{python-foo}; if it compiles only with Python 2, we name it
17989 @code{python2-foo}. If it is compatible with both versions, we create two
17990 packages with the corresponding names.
17992 If a project already contains the word @code{python}, we drop this;
17993 for instance, the module python-dateutil is packaged under the names
17994 @code{python-dateutil} and @code{python2-dateutil}. If the project name
17995 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
17998 @subsubsection Specifying Dependencies
17999 @cindex inputs, for Python packages
18001 Dependency information for Python packages is usually available in the
18002 package source tree, with varying degrees of accuracy: in the
18003 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
18005 Your mission, when writing a recipe for a Python package, is to map
18006 these dependencies to the appropriate type of ``input'' (@pxref{package
18007 Reference, inputs}). Although the @code{pypi} importer normally does a
18008 good job (@pxref{Invoking guix import}), you may want to check the
18009 following check list to determine which dependency goes where.
18014 We currently package Python 2 with @code{setuptools} and @code{pip}
18015 installed like Python 3.4 has per default. Thus you don't need to
18016 specify either of these as an input. @command{guix lint} will warn you
18020 Python dependencies required at run time go into
18021 @code{propagated-inputs}. They are typically defined with the
18022 @code{install_requires} keyword in @file{setup.py}, or in the
18023 @file{requirements.txt} file.
18026 Python packages required only at build time---e.g., those listed with
18027 the @code{setup_requires} keyword in @file{setup.py}---or only for
18028 testing---e.g., those in @code{tests_require}---go into
18029 @code{native-inputs}. The rationale is that (1) they do not need to be
18030 propagated because they are not needed at run time, and (2) in a
18031 cross-compilation context, it's the ``native'' input that we'd want.
18033 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
18034 frameworks. Of course if any of these packages is also required at
18035 run-time, it needs to go to @code{propagated-inputs}.
18038 Anything that does not fall in the previous categories goes to
18039 @code{inputs}, for example programs or C libraries required for building
18040 Python packages containing C extensions.
18043 If a Python package has optional dependencies (@code{extras_require}),
18044 it is up to you to decide whether to add them or not, based on their
18045 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
18052 @subsection Perl Modules
18055 Perl programs standing for themselves are named as any other package,
18056 using the lowercase upstream name.
18057 For Perl packages containing a single class, we use the lowercase class name,
18058 replace all occurrences of @code{::} by dashes and prepend the prefix
18060 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
18061 Modules containing several classes keep their lowercase upstream name and
18062 are also prepended by @code{perl-}. Such modules tend to have the word
18063 @code{perl} somewhere in their name, which gets dropped in favor of the
18064 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
18067 @node Java Packages
18068 @subsection Java Packages
18071 Java programs standing for themselves are named as any other package,
18072 using the lowercase upstream name.
18074 To avoid confusion and naming clashes with other programming languages,
18075 it is desirable that the name of a package for a Java package is
18076 prefixed with @code{java-}. If a project already contains the word
18077 @code{java}, we drop this; for instance, the package @code{ngsjava} is
18078 packaged under the name @code{java-ngs}.
18080 For Java packages containing a single class or a small class hierarchy,
18081 we use the lowercase class name, replace all occurrences of @code{.} by
18082 dashes and prepend the prefix @code{java-}. So the class
18083 @code{apache.commons.cli} becomes package
18084 @code{java-apache-commons-cli}.
18091 For fonts that are in general not installed by a user for typesetting
18092 purposes, or that are distributed as part of a larger software package,
18093 we rely on the general packaging rules for software; for instance, this
18094 applies to the fonts delivered as part of the X.Org system or fonts that
18095 are part of TeX Live.
18097 To make it easier for a user to search for fonts, names for other packages
18098 containing only fonts are constructed as follows, independently of the
18099 upstream package name.
18101 The name of a package containing only one font family starts with
18102 @code{font-}; it is followed by the foundry name and a dash @code{-}
18103 if the foundry is known, and the font family name, in which spaces are
18104 replaced by dashes (and as usual, all upper case letters are transformed
18106 For example, the Gentium font family by SIL is packaged under the name
18107 @code{font-sil-gentium}.
18109 For a package containing several font families, the name of the collection
18110 is used in the place of the font family name.
18111 For instance, the Liberation fonts consist of three families,
18112 Liberation Sans, Liberation Serif and Liberation Mono.
18113 These could be packaged separately under the names
18114 @code{font-liberation-sans} and so on; but as they are distributed together
18115 under a common name, we prefer to package them together as
18116 @code{font-liberation}.
18118 In the case where several formats of the same font family or font collection
18119 are packaged separately, a short form of the format, prepended by a dash,
18120 is added to the package name. We use @code{-ttf} for TrueType fonts,
18121 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
18126 @node Bootstrapping
18127 @section Bootstrapping
18129 @c Adapted from the ELS 2013 paper.
18131 @cindex bootstrapping
18133 Bootstrapping in our context refers to how the distribution gets built
18134 ``from nothing''. Remember that the build environment of a derivation
18135 contains nothing but its declared inputs (@pxref{Introduction}). So
18136 there's an obvious chicken-and-egg problem: how does the first package
18137 get built? How does the first compiler get compiled? Note that this is
18138 a question of interest only to the curious hacker, not to the regular
18139 user, so you can shamelessly skip this section if you consider yourself
18140 a ``regular user''.
18142 @cindex bootstrap binaries
18143 The GNU system is primarily made of C code, with libc at its core. The
18144 GNU build system itself assumes the availability of a Bourne shell and
18145 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
18146 `grep'. Furthermore, build programs---programs that run
18147 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
18148 (@pxref{Derivations}). Consequently, to be able to build anything at
18149 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
18150 Binutils, libc, and the other packages mentioned above---the
18151 @dfn{bootstrap binaries}.
18153 These bootstrap binaries are ``taken for granted'', though we can also
18154 re-create them if needed (more on that later).
18156 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
18158 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
18159 @c large image, it's hard to scroll. Oh well.
18160 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
18162 The figure above shows the very beginning of the dependency graph of the
18163 distribution, corresponding to the package definitions of the @code{(gnu
18164 packages bootstrap)} module. A similar figure can be generated with
18165 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
18168 guix graph -t derivation \
18169 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
18173 At this level of detail, things are
18174 slightly complex. First, Guile itself consists of an ELF executable,
18175 along with many source and compiled Scheme files that are dynamically
18176 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
18177 tarball shown in this graph. This tarball is part of Guix's ``source''
18178 distribution, and gets inserted into the store with @code{add-to-store}
18179 (@pxref{The Store}).
18181 But how do we write a derivation that unpacks this tarball and adds it
18182 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
18183 derivation---the first one that gets built---uses @code{bash} as its
18184 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
18185 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
18186 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
18187 the Guix source distribution, whose sole purpose is to allow the Guile
18188 tarball to be unpacked.
18190 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
18191 Guile that can be used to run subsequent build programs. Its first task
18192 is to download tarballs containing the other pre-built binaries---this
18193 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
18194 @code{ftp-client.scm} are used for this purpose. The
18195 @code{module-import.drv} derivations import those modules in a directory
18196 in the store, using the original layout. The
18197 @code{module-import-compiled.drv} derivations compile those modules, and
18198 write them in an output directory with the right layout. This
18199 corresponds to the @code{#:modules} argument of
18200 @code{build-expression->derivation} (@pxref{Derivations}).
18202 Finally, the various tarballs are unpacked by the
18203 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
18204 etc., at which point we have a working C tool chain.
18207 @unnumberedsubsec Building the Build Tools
18209 Bootstrapping is complete when we have a full tool chain that does not
18210 depend on the pre-built bootstrap tools discussed above. This
18211 no-dependency requirement is verified by checking whether the files of
18212 the final tool chain contain references to the @file{/gnu/store}
18213 directories of the bootstrap inputs. The process that leads to this
18214 ``final'' tool chain is described by the package definitions found in
18215 the @code{(gnu packages commencement)} module.
18217 The @command{guix graph} command allows us to ``zoom out'' compared to
18218 the graph above, by looking at the level of package objects instead of
18219 individual derivations---remember that a package may translate to
18220 several derivations, typically one derivation to download its source,
18221 one to build the Guile modules it needs, and one to actually build the
18222 package from source. The command:
18225 guix graph -t bag \
18226 -e '(@@@@ (gnu packages commencement)
18227 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
18231 produces the dependency graph leading to the ``final'' C
18232 library@footnote{You may notice the @code{glibc-intermediate} label,
18233 suggesting that it is not @emph{quite} final, but as a good
18234 approximation, we will consider it final.}, depicted below.
18236 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
18238 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
18239 The first tool that gets built with the bootstrap binaries is
18240 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
18241 for all the following packages. From there Findutils and Diffutils get
18244 Then come the first-stage Binutils and GCC, built as pseudo cross
18245 tools---i.e., with @code{--target} equal to @code{--host}. They are
18246 used to build libc. Thanks to this cross-build trick, this libc is
18247 guaranteed not to hold any reference to the initial tool chain.
18249 From there the final Binutils and GCC (not shown above) are built.
18251 from the final Binutils, and links programs against the just-built libc.
18252 This tool chain is used to build the other packages used by Guix and by
18253 the GNU Build System: Guile, Bash, Coreutils, etc.
18255 And voilà! At this point we have the complete set of build tools that
18256 the GNU Build System expects. These are in the @code{%final-inputs}
18257 variable of the @code{(gnu packages commencement)} module, and are
18258 implicitly used by any package that uses @code{gnu-build-system}
18259 (@pxref{Build Systems, @code{gnu-build-system}}).
18262 @unnumberedsubsec Building the Bootstrap Binaries
18264 @cindex bootstrap binaries
18265 Because the final tool chain does not depend on the bootstrap binaries,
18266 those rarely need to be updated. Nevertheless, it is useful to have an
18267 automated way to produce them, should an update occur, and this is what
18268 the @code{(gnu packages make-bootstrap)} module provides.
18270 The following command builds the tarballs containing the bootstrap
18271 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
18272 of Coreutils and other basic command-line tools):
18275 guix build bootstrap-tarballs
18278 The generated tarballs are those that should be referred to in the
18279 @code{(gnu packages bootstrap)} module mentioned at the beginning of
18282 Still here? Then perhaps by now you've started to wonder: when do we
18283 reach a fixed point? That is an interesting question! The answer is
18284 unknown, but if you would like to investigate further (and have
18285 significant computational and storage resources to do so), then let us
18289 @section Porting to a New Platform
18291 As discussed above, the GNU distribution is self-contained, and
18292 self-containment is achieved by relying on pre-built ``bootstrap
18293 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
18294 operating system kernel, CPU architecture, and application binary
18295 interface (ABI). Thus, to port the distribution to a platform that is
18296 not yet supported, one must build those bootstrap binaries, and update
18297 the @code{(gnu packages bootstrap)} module to use them on that platform.
18299 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
18300 When everything goes well, and assuming the GNU tool chain supports the
18301 target platform, this can be as simple as running a command like this
18305 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
18308 For this to work, the @code{glibc-dynamic-linker} procedure in
18309 @code{(gnu packages bootstrap)} must be augmented to return the right
18310 file name for libc's dynamic linker on that platform; likewise,
18311 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
18312 taught about the new platform.
18314 Once these are built, the @code{(gnu packages bootstrap)} module needs
18315 to be updated to refer to these binaries on the target platform. That
18316 is, the hashes and URLs of the bootstrap tarballs for the new platform
18317 must be added alongside those of the currently supported platforms. The
18318 bootstrap Guile tarball is treated specially: it is expected to be
18319 available locally, and @file{gnu/local.mk} has rules do download it for
18320 the supported architectures; a rule for the new platform must be added
18323 In practice, there may be some complications. First, it may be that the
18324 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
18325 above) is not recognized by all the GNU tools. Typically, glibc
18326 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
18327 configure flag (see @code{gcc.scm} for examples of how to handle this).
18328 Second, some of the required packages could fail to build for that
18329 platform. Lastly, the generated binaries could be broken for some
18332 @c *********************************************************************
18333 @include contributing.texi
18335 @c *********************************************************************
18336 @node Acknowledgments
18337 @chapter Acknowledgments
18339 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
18340 which was designed and
18341 implemented by Eelco Dolstra, with contributions from other people (see
18342 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
18343 management, and promoted unprecedented features, such as transactional
18344 package upgrades and rollbacks, per-user profiles, and referentially
18345 transparent build processes. Without this work, Guix would not exist.
18347 The Nix-based software distributions, Nixpkgs and NixOS, have also been
18348 an inspiration for Guix.
18350 GNU@tie{}Guix itself is a collective work with contributions from a
18351 number of people. See the @file{AUTHORS} file in Guix for more
18352 information on these fine people. The @file{THANKS} file lists people
18353 who have helped by reporting bugs, taking care of the infrastructure,
18354 providing artwork and themes, making suggestions, and more---thank you!
18357 @c *********************************************************************
18358 @node GNU Free Documentation License
18359 @appendix GNU Free Documentation License
18360 @cindex license, GNU Free Documentation License
18361 @include fdl-1.3.texi
18363 @c *********************************************************************
18364 @node Concept Index
18365 @unnumbered Concept Index
18368 @node Programming Index
18369 @unnumbered Programming Index
18370 @syncodeindex tp fn
18371 @syncodeindex vr fn
18376 @c Local Variables:
18377 @c ispell-local-dictionary: "american";