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});
583 @item @url{http://www.gnu.org/software/make/, GNU Make}.
586 The following dependencies are optional:
591 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
592 allow you to use the @command{guix import pypi} command (@pxref{Invoking
593 guix import}). It is of
594 interest primarily for developers and not for casual users.
597 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
598 Support for build offloading (@pxref{Daemon Offload Setup}) and
599 @command{guix copy} (@pxref{Invoking guix copy}) depends on
600 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
601 version 0.10.2 or later.
604 When @url{http://zlib.net, zlib} is available, @command{guix publish}
605 can compress build byproducts (@pxref{Invoking guix publish}).
608 Unless @code{--disable-daemon} was passed to @command{configure}, the
609 following packages are also needed:
612 @item @url{http://sqlite.org, SQLite 3};
613 @item @url{http://www.bzip.org, libbz2};
614 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
618 @cindex state directory
619 When configuring Guix on a system that already has a Guix installation,
620 be sure to specify the same state directory as the existing installation
621 using the @code{--localstatedir} option of the @command{configure}
622 script (@pxref{Directory Variables, @code{localstatedir},, standards,
623 GNU Coding Standards}). The @command{configure} script protects against
624 unintended misconfiguration of @var{localstatedir} so you do not
625 inadvertently corrupt your store (@pxref{The Store}).
627 @cindex Nix, compatibility
628 When a working installation of @url{http://nixos.org/nix/, the Nix package
629 manager} is available, you
630 can instead configure Guix with @code{--disable-daemon}. In that case,
631 Nix replaces the three dependencies above.
633 Guix is compatible with Nix, so it is possible to share the same store
634 between both. To do so, you must pass @command{configure} not only the
635 same @code{--with-store-dir} value, but also the same
636 @code{--localstatedir} value. The latter is essential because it
637 specifies where the database that stores metadata about the store is
638 located, among other things. The default values for Nix are
639 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
640 Note that @code{--disable-daemon} is not required if
641 your goal is to share the store with Nix.
643 @node Running the Test Suite
644 @section Running the Test Suite
647 After a successful @command{configure} and @code{make} run, it is a good
648 idea to run the test suite. It can help catch issues with the setup or
649 environment, or bugs in Guix itself---and really, reporting test
650 failures is a good way to help improve the software. To run the test
657 Test cases can run in parallel: you can use the @code{-j} option of
658 GNU@tie{}make to speed things up. The first run may take a few minutes
659 on a recent machine; subsequent runs will be faster because the store
660 that is created for test purposes will already have various things in
663 It is also possible to run a subset of the tests by defining the
664 @code{TESTS} makefile variable as in this example:
667 make check TESTS="tests/store.scm tests/cpio.scm"
670 By default, tests results are displayed at a file level. In order to
671 see the details of every individual test cases, it is possible to define
672 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
675 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
678 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
679 @file{test-suite.log} file. Please specify the Guix version being used
680 as well as version numbers of the dependencies (@pxref{Requirements}) in
683 Guix also comes with a whole-system test suite that tests complete
684 GuixSD operating system instances. It can only run on systems where
685 Guix is already installed, using:
692 or, again, by defining @code{TESTS} to select a subset of tests to run:
695 make check-system TESTS="basic mcron"
698 These system tests are defined in the @code{(gnu tests @dots{})}
699 modules. They work by running the operating systems under test with
700 lightweight instrumentation in a virtual machine (VM). They can be
701 computationally intensive or rather cheap, depending on whether
702 substitutes are available for their dependencies (@pxref{Substitutes}).
703 Some of them require a lot of storage space to hold VM images.
705 Again in case of test failures, please send @email{bug-guix@@gnu.org}
708 @node Setting Up the Daemon
709 @section Setting Up the Daemon
712 Operations such as building a package or running the garbage collector
713 are all performed by a specialized process, the @dfn{build daemon}, on
714 behalf of clients. Only the daemon may access the store and its
715 associated database. Thus, any operation that manipulates the store
716 goes through the daemon. For instance, command-line tools such as
717 @command{guix package} and @command{guix build} communicate with the
718 daemon (@i{via} remote procedure calls) to instruct it what to do.
720 The following sections explain how to prepare the build daemon's
721 environment. See also @ref{Substitutes}, for information on how to allow
722 the daemon to download pre-built binaries.
725 * Build Environment Setup:: Preparing the isolated build environment.
726 * Daemon Offload Setup:: Offloading builds to remote machines.
729 @node Build Environment Setup
730 @subsection Build Environment Setup
732 @cindex build environment
733 In a standard multi-user setup, Guix and its daemon---the
734 @command{guix-daemon} program---are installed by the system
735 administrator; @file{/gnu/store} is owned by @code{root} and
736 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
737 Guix tools to build packages or otherwise access the store, and the
738 daemon will do it on their behalf, ensuring that the store is kept in a
739 consistent state, and allowing built packages to be shared among users.
742 When @command{guix-daemon} runs as @code{root}, you may not want package
743 build processes themselves to run as @code{root} too, for obvious
744 security reasons. To avoid that, a special pool of @dfn{build users}
745 should be created for use by build processes started by the daemon.
746 These build users need not have a shell and a home directory: they will
747 just be used when the daemon drops @code{root} privileges in build
748 processes. Having several such users allows the daemon to launch
749 distinct build processes under separate UIDs, which guarantees that they
750 do not interfere with each other---an essential feature since builds are
751 regarded as pure functions (@pxref{Introduction}).
753 On a GNU/Linux system, a build user pool may be created like this (using
754 Bash syntax and the @code{shadow} commands):
756 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
757 @c for why `-G' is needed.
759 # groupadd --system guixbuild
760 # for i in `seq -w 1 10`;
762 useradd -g guixbuild -G guixbuild \
763 -d /var/empty -s `which nologin` \
764 -c "Guix build user $i" --system \
770 The number of build users determines how many build jobs may run in
771 parallel, as specified by the @option{--max-jobs} option
772 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
773 @command{guix system vm} and related commands, you may need to add the
774 build users to the @code{kvm} group so they can access @file{/dev/kvm},
775 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
776 (@pxref{Invoking guix system}).
778 The @code{guix-daemon} program may then be run as @code{root} with the
779 following command@footnote{If your machine uses the systemd init system,
780 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
781 file in @file{/etc/systemd/system} will ensure that
782 @command{guix-daemon} is automatically started. Similarly, if your
783 machine uses the Upstart init system, drop the
784 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
785 file in @file{/etc/init}.}:
788 # guix-daemon --build-users-group=guixbuild
793 This way, the daemon starts build processes in a chroot, under one of
794 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
795 environment contains nothing but:
797 @c Keep this list in sync with libstore/build.cc! -----------------------
800 a minimal @code{/dev} directory, created mostly independently from the
801 host @code{/dev}@footnote{``Mostly'', because while the set of files
802 that appear in the chroot's @code{/dev} is fixed, most of these files
803 can only be created if the host has them.};
806 the @code{/proc} directory; it only shows the processes of the container
807 since a separate PID name space is used;
810 @file{/etc/passwd} with an entry for the current user and an entry for
814 @file{/etc/group} with an entry for the user's group;
817 @file{/etc/hosts} with an entry that maps @code{localhost} to
821 a writable @file{/tmp} directory.
824 You can influence the directory where the daemon stores build trees
825 @i{via} the @code{TMPDIR} environment variable. However, the build tree
826 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
827 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
828 This way, the value of @code{TMPDIR} does not leak inside build
829 environments, which avoids discrepancies in cases where build processes
830 capture the name of their build tree.
833 The daemon also honors the @code{http_proxy} environment variable for
834 HTTP downloads it performs, be it for fixed-output derivations
835 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
837 If you are installing Guix as an unprivileged user, it is still possible
838 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
839 However, build processes will not be isolated from one another, and not
840 from the rest of the system. Thus, build processes may interfere with
841 each other, and may access programs, libraries, and other files
842 available on the system---making it much harder to view them as
843 @emph{pure} functions.
846 @node Daemon Offload Setup
847 @subsection Using the Offload Facility
851 When desired, the build daemon can @dfn{offload} derivation builds to
852 other machines running Guix, using the @code{offload} @dfn{build
853 hook}@footnote{This feature is available only when
854 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
856 feature is enabled, a list of user-specified build machines is read from
857 @file{/etc/guix/machines.scm}; every time a build is requested, for
858 instance via @code{guix build}, the daemon attempts to offload it to one
859 of the machines that satisfy the constraints of the derivation, in
860 particular its system type---e.g., @file{x86_64-linux}. Missing
861 prerequisites for the build are copied over SSH to the target machine,
862 which then proceeds with the build; upon success the output(s) of the
863 build are copied back to the initial machine.
865 The @file{/etc/guix/machines.scm} file typically looks like this:
869 (name "eightysix.example.org")
870 (system "x86_64-linux")
871 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
873 (speed 2.)) ;incredibly fast!
876 (name "meeps.example.org")
877 (system "mips64el-linux")
878 (host-key "ssh-rsa AAAAB3Nza@dots{}")
881 (string-append (getenv "HOME")
882 "/.ssh/identity-for-guix"))))
886 In the example above we specify a list of two build machines, one for
887 the @code{x86_64} architecture and one for the @code{mips64el}
890 In fact, this file is---not surprisingly!---a Scheme file that is
891 evaluated when the @code{offload} hook is started. Its return value
892 must be a list of @code{build-machine} objects. While this example
893 shows a fixed list of build machines, one could imagine, say, using
894 DNS-SD to return a list of potential build machines discovered in the
895 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
896 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
899 @deftp {Data Type} build-machine
900 This data type represents build machines to which the daemon may offload
901 builds. The important fields are:
906 The host name of the remote machine.
909 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
912 The user account to use when connecting to the remote machine over SSH.
913 Note that the SSH key pair must @emph{not} be passphrase-protected, to
914 allow non-interactive logins.
917 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
918 This is used to authenticate the machine when we connect to it. It is a
919 long string that looks like this:
922 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
925 If the machine is running the OpenSSH daemon, @command{sshd}, the host
926 key can be found in a file such as
927 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
929 If the machine is running the SSH daemon of GNU@tie{}lsh,
930 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
931 similar file. It can be converted to the OpenSSH format using
932 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
935 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
936 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
941 A number of optional fields may be specified:
945 @item @code{port} (default: @code{22})
946 Port number of SSH server on the machine.
948 @item @code{private-key} (default: @file{~root/.ssh/id_rsa})
949 The SSH private key file to use when connecting to the machine, in
952 Note that the default value is the private key @emph{of the root
953 account}. Make sure it exists if you use the default.
955 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
956 @itemx @code{compression-level} (default: @code{3})
957 The SSH-level compression methods and compression level requested.
959 Note that offloading relies on SSH compression to reduce bandwidth usage
960 when transferring files to and from build machines.
962 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
963 File name of the Unix-domain socket @command{guix-daemon} is listening
966 @item @code{parallel-builds} (default: @code{1})
967 The number of builds that may run in parallel on the machine.
969 @item @code{speed} (default: @code{1.0})
970 A ``relative speed factor''. The offload scheduler will tend to prefer
971 machines with a higher speed factor.
973 @item @code{features} (default: @code{'()})
974 A list of strings denoting specific features supported by the machine.
975 An example is @code{"kvm"} for machines that have the KVM Linux modules
976 and corresponding hardware support. Derivations can request features by
977 name, and they will be scheduled on matching build machines.
982 The @code{guile} command must be in the search path on the build
983 machines. In addition, the Guix modules must be in
984 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
985 this is the case by running:
988 ssh build-machine guile -c "'(use-modules (guix config))'"
991 There is one last thing to do once @file{machines.scm} is in place. As
992 explained above, when offloading, files are transferred back and forth
993 between the machine stores. For this to work, you first need to
994 generate a key pair on each machine to allow the daemon to export signed
995 archives of files from the store (@pxref{Invoking guix archive}):
998 # guix archive --generate-key
1002 Each build machine must authorize the key of the master machine so that
1003 it accepts store items it receives from the master:
1006 # guix archive --authorize < master-public-key.txt
1010 Likewise, the master machine must authorize the key of each build machine.
1012 All the fuss with keys is here to express pairwise mutual trust
1013 relations between the master and the build machines. Concretely, when
1014 the master receives files from a build machine (and @i{vice versa}), its
1015 build daemon can make sure they are genuine, have not been tampered
1016 with, and that they are signed by an authorized key.
1018 @cindex offload test
1019 To test whether your setup is operational, run this command on the
1026 This will attempt to connect to each of the build machines specified in
1027 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1028 available on each machine, attempt to export to the machine and import
1029 from it, and report any error in the process.
1031 If you want to test a different machine file, just specify it on the
1035 # guix offload test machines-qualif.scm
1038 Last, you can test the subset of the machines whose name matches a
1039 regular expression like this:
1042 # guix offload test machines.scm '\.gnu\.org$'
1045 @node Invoking guix-daemon
1046 @section Invoking @command{guix-daemon}
1048 The @command{guix-daemon} program implements all the functionality to
1049 access the store. This includes launching build processes, running the
1050 garbage collector, querying the availability of a build result, etc. It
1051 is normally run as @code{root} like this:
1054 # guix-daemon --build-users-group=guixbuild
1058 For details on how to set it up, @pxref{Setting Up the Daemon}.
1061 @cindex container, build environment
1062 @cindex build environment
1063 @cindex reproducible builds
1064 By default, @command{guix-daemon} launches build processes under
1065 different UIDs, taken from the build group specified with
1066 @code{--build-users-group}. In addition, each build process is run in a
1067 chroot environment that only contains the subset of the store that the
1068 build process depends on, as specified by its derivation
1069 (@pxref{Programming Interface, derivation}), plus a set of specific
1070 system directories. By default, the latter contains @file{/dev} and
1071 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1072 @dfn{container}: in addition to having its own file system tree, it has
1073 a separate mount name space, its own PID name space, network name space,
1074 etc. This helps achieve reproducible builds (@pxref{Features}).
1076 When the daemon performs a build on behalf of the user, it creates a
1077 build directory under @file{/tmp} or under the directory specified by
1078 its @code{TMPDIR} environment variable; this directory is shared with
1079 the container for the duration of the build. Be aware that using a
1080 directory other than @file{/tmp} can affect build results---for example,
1081 with a longer directory name, a build process that uses Unix-domain
1082 sockets might hit the name length limitation for @code{sun_path}, which
1083 it would otherwise not hit.
1085 The build directory is automatically deleted upon completion, unless the
1086 build failed and the client specified @option{--keep-failed}
1087 (@pxref{Invoking guix build, @option{--keep-failed}}).
1089 The following command-line options are supported:
1092 @item --build-users-group=@var{group}
1093 Take users from @var{group} to run build processes (@pxref{Setting Up
1094 the Daemon, build users}).
1096 @item --no-substitutes
1098 Do not use substitutes for build products. That is, always build things
1099 locally instead of allowing downloads of pre-built binaries
1100 (@pxref{Substitutes}).
1102 By default substitutes are used, unless the client---such as the
1103 @command{guix package} command---is explicitly invoked with
1104 @code{--no-substitutes}.
1106 When the daemon runs with @code{--no-substitutes}, clients can still
1107 explicitly enable substitution @i{via} the @code{set-build-options}
1108 remote procedure call (@pxref{The Store}).
1110 @item --substitute-urls=@var{urls}
1111 @anchor{daemon-substitute-urls}
1112 Consider @var{urls} the default whitespace-separated list of substitute
1113 source URLs. When this option is omitted,
1114 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1115 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1117 This means that substitutes may be downloaded from @var{urls}, as long
1118 as they are signed by a trusted signature (@pxref{Substitutes}).
1121 @item --no-build-hook
1122 Do not use the @dfn{build hook}.
1124 The build hook is a helper program that the daemon can start and to
1125 which it submits build requests. This mechanism is used to offload
1126 builds to other machines (@pxref{Daemon Offload Setup}).
1128 @item --cache-failures
1129 Cache build failures. By default, only successful builds are cached.
1131 When this option is used, @command{guix gc --list-failures} can be used
1132 to query the set of store items marked as failed; @command{guix gc
1133 --clear-failures} removes store items from the set of cached failures.
1134 @xref{Invoking guix gc}.
1136 @item --cores=@var{n}
1138 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1141 The default value is @code{0}, but it may be overridden by clients, such
1142 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1145 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1146 in the build process, which can then use it to exploit internal
1147 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1149 @item --max-jobs=@var{n}
1151 Allow at most @var{n} build jobs in parallel. The default value is
1152 @code{1}. Setting it to @code{0} means that no builds will be performed
1153 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1154 Setup}), or simply fail.
1156 @item --max-silent-time=@var{seconds}
1157 When the build or substitution process remains silent for more than
1158 @var{seconds}, terminate it and report a build failure.
1160 The default value is @code{0}, which disables the timeout.
1162 The value specified here can be overridden by clients (@pxref{Common
1163 Build Options, @code{--max-silent-time}}).
1165 @item --timeout=@var{seconds}
1166 Likewise, when the build or substitution process lasts for more than
1167 @var{seconds}, terminate it and report a build failure.
1169 The default value is @code{0}, which disables the timeout.
1171 The value specified here can be overridden by clients (@pxref{Common
1172 Build Options, @code{--timeout}}).
1174 @item --rounds=@var{N}
1175 Build each derivation @var{n} times in a row, and raise an error if
1176 consecutive build results are not bit-for-bit identical. Note that this
1177 setting can be overridden by clients such as @command{guix build}
1178 (@pxref{Invoking guix build}).
1180 When used in conjunction with @option{--keep-failed}, the differing
1181 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1182 This makes it easy to look for differences between the two results.
1185 Produce debugging output.
1187 This is useful to debug daemon start-up issues, but then it may be
1188 overridden by clients, for example the @code{--verbosity} option of
1189 @command{guix build} (@pxref{Invoking guix build}).
1191 @item --chroot-directory=@var{dir}
1192 Add @var{dir} to the build chroot.
1194 Doing this may change the result of build processes---for instance if
1195 they use optional dependencies found in @var{dir} when it is available,
1196 and not otherwise. For that reason, it is not recommended to do so.
1197 Instead, make sure that each derivation declares all the inputs that it
1200 @item --disable-chroot
1201 Disable chroot builds.
1203 Using this option is not recommended since, again, it would allow build
1204 processes to gain access to undeclared dependencies. It is necessary,
1205 though, when @command{guix-daemon} is running under an unprivileged user
1208 @item --disable-log-compression
1209 Disable compression of the build logs.
1211 Unless @code{--lose-logs} is used, all the build logs are kept in the
1212 @var{localstatedir}. To save space, the daemon automatically compresses
1213 them with bzip2 by default. This option disables that.
1215 @item --disable-deduplication
1216 @cindex deduplication
1217 Disable automatic file ``deduplication'' in the store.
1219 By default, files added to the store are automatically ``deduplicated'':
1220 if a newly added file is identical to another one found in the store,
1221 the daemon makes the new file a hard link to the other file. This can
1222 noticeably reduce disk usage, at the expense of slightly increased
1223 input/output load at the end of a build process. This option disables
1226 @item --gc-keep-outputs[=yes|no]
1227 Tell whether the garbage collector (GC) must keep outputs of live
1230 When set to ``yes'', the GC will keep the outputs of any live derivation
1231 available in the store---the @code{.drv} files. The default is ``no'',
1232 meaning that derivation outputs are kept only if they are GC roots.
1234 @item --gc-keep-derivations[=yes|no]
1235 Tell whether the garbage collector (GC) must keep derivations
1236 corresponding to live outputs.
1238 When set to ``yes'', as is the case by default, the GC keeps
1239 derivations---i.e., @code{.drv} files---as long as at least one of their
1240 outputs is live. This allows users to keep track of the origins of
1241 items in their store. Setting it to ``no'' saves a bit of disk space.
1243 Note that when both @code{--gc-keep-derivations} and
1244 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1245 prerequisites (the sources, compiler, libraries, and other build-time
1246 tools) of live objects in the store, regardless of whether these
1247 prerequisites are live. This is convenient for developers since it
1248 saves rebuilds or downloads.
1250 @item --impersonate-linux-2.6
1251 On Linux-based systems, impersonate Linux 2.6. This means that the
1252 kernel's @code{uname} system call will report 2.6 as the release number.
1254 This might be helpful to build programs that (usually wrongfully) depend
1255 on the kernel version number.
1258 Do not keep build logs. By default they are kept under
1259 @code{@var{localstatedir}/guix/log}.
1261 @item --system=@var{system}
1262 Assume @var{system} as the current system type. By default it is the
1263 architecture/kernel pair found at configure time, such as
1264 @code{x86_64-linux}.
1266 @item --listen=@var{endpoint}
1267 Listen for connections on @var{endpoint}. @var{endpoint} is interpreted
1268 as the file name of a Unix-domain socket if it starts with
1269 @code{/} (slash sign). Otherwise, @var{endpoint} is interpreted as a
1270 host name or host name and port to listen to. Here are a few examples:
1273 @item --listen=/gnu/var/daemon
1274 Listen for connections on the @file{/gnu/var/daemon} Unix-domain socket,
1275 creating it if needed.
1277 @item --listen=localhost
1278 @cindex daemon, remote access
1279 @cindex remote access to the daemon
1280 @cindex daemon, cluster setup
1281 @cindex clusters, daemon setup
1282 Listen for TCP connections on the network interface corresponding to
1283 @code{localhost}, on port 44146.
1285 @item --listen=128.0.0.42:1234
1286 Listen for TCP connections on the network interface corresponding to
1287 @code{128.0.0.42}, on port 1234.
1290 This option can be repeated multiple times, in which case
1291 @command{guix-daemon} accepts connections on all the specified
1292 endpoints. Users can tell client commands what endpoint to connect to
1293 by setting the @code{GUIX_DAEMON_SOCKET} environment variable
1294 (@pxref{The Store, @code{GUIX_DAEMON_SOCKET}}).
1297 The daemon protocol is @emph{unauthenticated and unencrypted}. Using
1298 @code{--listen=@var{host}} is suitable on local networks, such as
1299 clusters, where only trusted nodes may connect to the build daemon. In
1300 other cases where remote access to the daemon is needed, we recommend
1301 using Unix-domain sockets along with SSH.
1304 When @code{--listen} is omitted, @command{guix-daemon} listens for
1305 connections on the Unix-domain socket located at
1306 @file{@var{localstatedir}/daemon-socket/socket}.
1310 @node Application Setup
1311 @section Application Setup
1313 @cindex foreign distro
1314 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1315 so-called @dfn{foreign distro}---a few additional steps are needed to
1316 get everything in place. Here are some of them.
1320 @anchor{locales-and-locpath}
1321 @cindex locales, when not on GuixSD
1323 @vindex GUIX_LOCPATH
1324 Packages installed @i{via} Guix will not use the locale data of the
1325 host system. Instead, you must first install one of the locale packages
1326 available with Guix and then define the @code{GUIX_LOCPATH} environment
1330 $ guix package -i glibc-locales
1331 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1334 Note that the @code{glibc-locales} package contains data for all the
1335 locales supported by the GNU@tie{}libc and weighs in at around
1336 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1337 limited to a few UTF-8 locales.
1339 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1340 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1341 Manual}). There are two important differences though:
1345 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1346 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1347 to make sure the programs of the foreign distro will not end up loading
1348 incompatible locale data.
1351 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1352 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1353 should your Guix profile contain a mixture of programs linked against
1354 different libc version, each libc version will only try to load locale
1355 data in the right format.
1358 This is important because the locale data format used by different libc
1359 versions may be incompatible.
1361 @subsection Name Service Switch
1363 @cindex name service switch, glibc
1364 @cindex NSS (name service switch), glibc
1365 @cindex nscd (name service caching daemon)
1366 @cindex name service caching daemon (nscd)
1367 When using Guix on a foreign distro, we @emph{strongly recommend} that
1368 the system run the GNU C library's @dfn{name service cache daemon},
1369 @command{nscd}, which should be listening on the
1370 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1371 installed with Guix may fail to look up host names or user accounts, or
1372 may even crash. The next paragraphs explain why.
1374 @cindex @file{nsswitch.conf}
1375 The GNU C library implements a @dfn{name service switch} (NSS), which is
1376 an extensible mechanism for ``name lookups'' in general: host name
1377 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1378 The GNU C Library Reference Manual}).
1380 @cindex Network information service (NIS)
1381 @cindex NIS (Network information service)
1382 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1383 lookup implementations: for example, the @code{nss-mdns} plugin allow
1384 resolution of @code{.local} host names, the @code{nis} plugin allows
1385 user account lookup using the Network information service (NIS), and so
1386 on. These extra ``lookup services'' are configured system-wide in
1387 @file{/etc/nsswitch.conf}, and all the programs running on the system
1388 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1391 When they perform a name lookup---for instance by calling the
1392 @code{getaddrinfo} function in C---applications first try to connect to
1393 the nscd; on success, nscd performs name lookups on their behalf. If
1394 the nscd is not running, then they perform the name lookup by
1395 themselves, by loading the name lookup services into their own address
1396 space and running it. These name lookup services---the
1397 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1398 the host system's C library, rather than from the C library the
1399 application is linked against (the C library coming from Guix).
1401 And this is where the problem is: if your application is linked against
1402 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1403 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1404 likely crash or have its name lookups fail unexpectedly.
1406 Running @command{nscd} on the system, among other advantages, eliminates
1407 this binary incompatibility problem because those @code{libnss_*.so}
1408 files are loaded in the @command{nscd} process, not in applications
1411 @subsection X11 Fonts
1414 The majority of graphical applications use Fontconfig to locate and
1415 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1416 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1417 by default. Thus, to allow graphical applications installed with Guix
1418 to display fonts, you have to install fonts with Guix as well.
1419 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1420 @code{font-gnu-freefont-ttf}.
1422 To display text written in Chinese languages, Japanese, or Korean in
1423 graphical applications, consider installing
1424 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1425 has multiple outputs, one per language family (@pxref{Packages with
1426 Multiple Outputs}). For instance, the following command installs fonts
1427 for Chinese languages:
1430 guix package -i font-adobe-source-han-sans:cn
1433 @cindex @code{xterm}
1434 Older programs such as @command{xterm} do not use Fontconfig and instead
1435 rely on server-side font rendering. Such programs require to specify a
1436 full name of a font using XLFD (X Logical Font Description), like this:
1439 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1442 To be able to use such full names for the TrueType fonts installed in
1443 your Guix profile, you need to extend the font path of the X server:
1446 xset +fp ~/.guix-profile/share/fonts/truetype
1449 @cindex @code{xlsfonts}
1450 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1451 to make sure your TrueType fonts are listed there.
1453 @cindex @code{fc-cache}
1455 After installing fonts you may have to refresh the font cache to use
1456 them in applications. The same applies when applications installed via
1457 Guix do not seem to find fonts. To force rebuilding of the font cache
1458 run @code{fc-cache -f}. The @code{fc-cache} command is provided by the
1459 @code{fontconfig} package.
1461 @subsection X.509 Certificates
1463 @cindex @code{nss-certs}
1464 The @code{nss-certs} package provides X.509 certificates, which allow
1465 programs to authenticate Web servers accessed over HTTPS.
1467 When using Guix on a foreign distro, you can install this package and
1468 define the relevant environment variables so that packages know where to
1469 look for certificates. @xref{X.509 Certificates}, for detailed
1472 @subsection Emacs Packages
1474 @cindex @code{emacs}
1475 When you install Emacs packages with Guix, the elisp files may be placed
1476 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1478 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1479 directory exists because potentially there may exist thousands of Emacs
1480 packages and storing all their files in a single directory may be not
1481 reliable (because of name conflicts). So we think using a separate
1482 directory for each package is a good idea. It is very similar to how
1483 the Emacs package system organizes the file structure (@pxref{Package
1484 Files,,, emacs, The GNU Emacs Manual}).
1486 By default, Emacs (installed with Guix) ``knows'' where these packages
1487 are placed, so you do not need to perform any configuration. If, for
1488 some reason, you want to avoid auto-loading Emacs packages installed
1489 with Guix, you can do so by running Emacs with @code{--no-site-file}
1490 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1492 @subsection The GCC toolchain
1497 Guix offers individual compiler packages such as @code{gcc} but if you
1498 are in need of a complete toolchain for compiling and linking source
1499 code what you really want is the @code{gcc-toolchain} package. This
1500 package provides a complete GCC toolchain for C/C++ development,
1501 including GCC itself, the GNU C Library (headers and binaries, plus
1502 debugging symbols in the @code{debug} output), Binutils, and a linker
1505 @cindex attempt to use impure library, error message
1507 The wrapper's purpose is to inspect the @code{-L} and @code{-l} switches
1508 passed to the linker, add corresponding @code{-rpath} arguments, and
1509 invoke the actual linker with this new set of arguments. By default,
1510 the linker wrapper refuses to link to libraries outside the store to
1511 ensure ``purity''. This can be annoying when using the toolchain to
1512 link with local libraries. To allow references to libraries outside the
1513 store you need to define the environment variable
1514 @code{GUIX_LD_WRAPPER_ALLOW_IMPURITIES}.
1518 @c *********************************************************************
1519 @node Package Management
1520 @chapter Package Management
1523 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1524 remove software packages, without having to know about their build
1525 procedures or dependencies. Guix also goes beyond this obvious set of
1528 This chapter describes the main features of Guix, as well as the
1529 package management tools it provides. Along with the command-line
1530 interface described below (@pxref{Invoking guix package, @code{guix
1531 package}}), you may also use Emacs Interface (@pxref{Top,,,
1532 emacs-guix, The Emacs-Guix Reference Manual}), after installing
1533 @code{emacs-guix} package (run @kbd{M-x guix-help} command to start
1537 guix package -i emacs-guix
1541 * Features:: How Guix will make your life brighter.
1542 * Invoking guix package:: Package installation, removal, etc.
1543 * Substitutes:: Downloading pre-built binaries.
1544 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1545 * Invoking guix gc:: Running the garbage collector.
1546 * Invoking guix pull:: Fetching the latest Guix and distribution.
1547 * Invoking guix pack:: Creating software bundles.
1548 * Invoking guix archive:: Exporting and importing store files.
1554 When using Guix, each package ends up in the @dfn{package store}, in its
1555 own directory---something that resembles
1556 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1558 Instead of referring to these directories, users have their own
1559 @dfn{profile}, which points to the packages that they actually want to
1560 use. These profiles are stored within each user's home directory, at
1561 @code{$HOME/.guix-profile}.
1563 For example, @code{alice} installs GCC 4.7.2. As a result,
1564 @file{/home/alice/.guix-profile/bin/gcc} points to
1565 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1566 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1567 simply continues to point to
1568 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1569 coexist on the same system without any interference.
1571 The @command{guix package} command is the central tool to manage
1572 packages (@pxref{Invoking guix package}). It operates on the per-user
1573 profiles, and can be used @emph{with normal user privileges}.
1575 @cindex transactions
1576 The command provides the obvious install, remove, and upgrade
1577 operations. Each invocation is actually a @emph{transaction}: either
1578 the specified operation succeeds, or nothing happens. Thus, if the
1579 @command{guix package} process is terminated during the transaction,
1580 or if a power outage occurs during the transaction, then the user's
1581 profile remains in its previous state, and remains usable.
1583 In addition, any package transaction may be @emph{rolled back}. So, if,
1584 for example, an upgrade installs a new version of a package that turns
1585 out to have a serious bug, users may roll back to the previous instance
1586 of their profile, which was known to work well. Similarly, the global
1587 system configuration on GuixSD is subject to
1588 transactional upgrades and roll-back
1589 (@pxref{Using the Configuration System}).
1591 All packages in the package store may be @emph{garbage-collected}.
1592 Guix can determine which packages are still referenced by user
1593 profiles, and remove those that are provably no longer referenced
1594 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1595 generations of their profile so that the packages they refer to can be
1598 @cindex reproducibility
1599 @cindex reproducible builds
1600 Finally, Guix takes a @dfn{purely functional} approach to package
1601 management, as described in the introduction (@pxref{Introduction}).
1602 Each @file{/gnu/store} package directory name contains a hash of all the
1603 inputs that were used to build that package---compiler, libraries, build
1604 scripts, etc. This direct correspondence allows users to make sure a
1605 given package installation matches the current state of their
1606 distribution. It also helps maximize @dfn{build reproducibility}:
1607 thanks to the isolated build environments that are used, a given build
1608 is likely to yield bit-identical files when performed on different
1609 machines (@pxref{Invoking guix-daemon, container}).
1612 This foundation allows Guix to support @dfn{transparent binary/source
1613 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1614 available from an external source---a @dfn{substitute}, Guix just
1615 downloads it and unpacks it;
1616 otherwise, it builds the package from source, locally
1617 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1618 reproducible, users do not have to trust servers that provide
1619 substitutes: they can force a local build and @emph{challenge} providers
1620 (@pxref{Invoking guix challenge}).
1622 Control over the build environment is a feature that is also useful for
1623 developers. The @command{guix environment} command allows developers of
1624 a package to quickly set up the right development environment for their
1625 package, without having to manually install the dependencies of the
1626 package into their profile (@pxref{Invoking guix environment}).
1628 @node Invoking guix package
1629 @section Invoking @command{guix package}
1631 @cindex installing packages
1632 @cindex removing packages
1633 @cindex package installation
1634 @cindex package removal
1635 The @command{guix package} command is the tool that allows users to
1636 install, upgrade, and remove packages, as well as rolling back to
1637 previous configurations. It operates only on the user's own profile,
1638 and works with normal user privileges (@pxref{Features}). Its syntax
1642 guix package @var{options}
1644 @cindex transactions
1645 Primarily, @var{options} specifies the operations to be performed during
1646 the transaction. Upon completion, a new profile is created, but
1647 previous @dfn{generations} of the profile remain available, should the user
1650 For example, to remove @code{lua} and install @code{guile} and
1651 @code{guile-cairo} in a single transaction:
1654 guix package -r lua -i guile guile-cairo
1657 @command{guix package} also supports a @dfn{declarative approach}
1658 whereby the user specifies the exact set of packages to be available and
1659 passes it @i{via} the @option{--manifest} option
1660 (@pxref{profile-manifest, @option{--manifest}}).
1663 For each user, a symlink to the user's default profile is automatically
1664 created in @file{$HOME/.guix-profile}. This symlink always points to the
1665 current generation of the user's default profile. Thus, users can add
1666 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1667 variable, and so on.
1668 @cindex search paths
1669 If you are not using the Guix System Distribution, consider adding the
1670 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1671 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1672 shells get all the right environment variable definitions:
1675 GUIX_PROFILE="$HOME/.guix-profile" \
1676 source "$HOME/.guix-profile/etc/profile"
1679 In a multi-user setup, user profiles are stored in a place registered as
1680 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1681 to (@pxref{Invoking guix gc}). That directory is normally
1682 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1683 @var{localstatedir} is the value passed to @code{configure} as
1684 @code{--localstatedir}, and @var{user} is the user name. The
1685 @file{per-user} directory is created when @command{guix-daemon} is
1686 started, and the @var{user} sub-directory is created by @command{guix
1689 The @var{options} can be among the following:
1693 @item --install=@var{package} @dots{}
1694 @itemx -i @var{package} @dots{}
1695 Install the specified @var{package}s.
1697 Each @var{package} may specify either a simple package name, such as
1698 @code{guile}, or a package name followed by an at-sign and version number,
1699 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1700 case, the newest version prefixed by @code{1.8} is selected.)
1702 If no version number is specified, the
1703 newest available version will be selected. In addition, @var{package}
1704 may contain a colon, followed by the name of one of the outputs of the
1705 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1706 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1707 name (and optionally version) are searched for among the GNU
1708 distribution modules (@pxref{Package Modules}).
1710 @cindex propagated inputs
1711 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1712 that automatically get installed along with the required package
1713 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1714 @code{package} objects}, for information about propagated inputs in
1715 package definitions).
1717 @anchor{package-cmd-propagated-inputs}
1718 An example is the GNU MPC library: its C header files refer to those of
1719 the GNU MPFR library, which in turn refer to those of the GMP library.
1720 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1721 in the profile; removing MPC also removes MPFR and GMP---unless they had
1722 also been explicitly installed by the user.
1724 Besides, packages sometimes rely on the definition of environment
1725 variables for their search paths (see explanation of
1726 @code{--search-paths} below). Any missing or possibly incorrect
1727 environment variable definitions are reported here.
1729 @item --install-from-expression=@var{exp}
1731 Install the package @var{exp} evaluates to.
1733 @var{exp} must be a Scheme expression that evaluates to a
1734 @code{<package>} object. This option is notably useful to disambiguate
1735 between same-named variants of a package, with expressions such as
1736 @code{(@@ (gnu packages base) guile-final)}.
1738 Note that this option installs the first output of the specified
1739 package, which may be insufficient when needing a specific output of a
1740 multiple-output package.
1742 @item --install-from-file=@var{file}
1743 @itemx -f @var{file}
1744 Install the package that the code within @var{file} evaluates to.
1746 As an example, @var{file} might contain a definition like this
1747 (@pxref{Defining Packages}):
1750 @verbatiminclude package-hello.scm
1753 Developers may find it useful to include such a @file{guix.scm} file
1754 in the root of their project source tree that can be used to test
1755 development snapshots and create reproducible development environments
1756 (@pxref{Invoking guix environment}).
1758 @item --remove=@var{package} @dots{}
1759 @itemx -r @var{package} @dots{}
1760 Remove the specified @var{package}s.
1762 As for @code{--install}, each @var{package} may specify a version number
1763 and/or output name in addition to the package name. For instance,
1764 @code{-r glibc:debug} would remove the @code{debug} output of
1767 @item --upgrade[=@var{regexp} @dots{}]
1768 @itemx -u [@var{regexp} @dots{}]
1769 @cindex upgrading packages
1770 Upgrade all the installed packages. If one or more @var{regexp}s are
1771 specified, upgrade only installed packages whose name matches a
1772 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1774 Note that this upgrades package to the latest version of packages found
1775 in the distribution currently installed. To update your distribution,
1776 you should regularly run @command{guix pull} (@pxref{Invoking guix
1779 @item --do-not-upgrade[=@var{regexp} @dots{}]
1780 When used together with the @code{--upgrade} option, do @emph{not}
1781 upgrade any packages whose name matches a @var{regexp}. For example, to
1782 upgrade all packages in the current profile except those containing the
1783 substring ``emacs'':
1786 $ guix package --upgrade . --do-not-upgrade emacs
1789 @item @anchor{profile-manifest}--manifest=@var{file}
1790 @itemx -m @var{file}
1791 @cindex profile declaration
1792 @cindex profile manifest
1793 Create a new generation of the profile from the manifest object
1794 returned by the Scheme code in @var{file}.
1796 This allows you to @emph{declare} the profile's contents rather than
1797 constructing it through a sequence of @code{--install} and similar
1798 commands. The advantage is that @var{file} can be put under version
1799 control, copied to different machines to reproduce the same profile, and
1802 @c FIXME: Add reference to (guix profile) documentation when available.
1803 @var{file} must return a @dfn{manifest} object, which is roughly a list
1806 @findex packages->manifest
1808 (use-package-modules guile emacs)
1813 ;; Use a specific package output.
1814 (list guile-2.0 "debug")))
1817 @findex specifications->manifest
1818 In this example we have to know which modules define the @code{emacs}
1819 and @code{guile-2.0} variables to provide the right
1820 @code{use-package-modules} line, which can be cumbersome. We can
1821 instead provide regular package specifications and let
1822 @code{specifications->manifest} look up the corresponding package
1826 (specifications->manifest
1827 '("emacs" "guile@@2.2" "guile@@2.2:debug"))
1831 @cindex rolling back
1832 @cindex undoing transactions
1833 @cindex transactions, undoing
1834 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1835 the last transaction.
1837 When combined with options such as @code{--install}, roll back occurs
1838 before any other actions.
1840 When rolling back from the first generation that actually contains
1841 installed packages, the profile is made to point to the @dfn{zeroth
1842 generation}, which contains no files apart from its own metadata.
1844 After having rolled back, installing, removing, or upgrading packages
1845 overwrites previous future generations. Thus, the history of the
1846 generations in a profile is always linear.
1848 @item --switch-generation=@var{pattern}
1849 @itemx -S @var{pattern}
1851 Switch to a particular generation defined by @var{pattern}.
1853 @var{pattern} may be either a generation number or a number prefixed
1854 with ``+'' or ``-''. The latter means: move forward/backward by a
1855 specified number of generations. For example, if you want to return to
1856 the latest generation after @code{--roll-back}, use
1857 @code{--switch-generation=+1}.
1859 The difference between @code{--roll-back} and
1860 @code{--switch-generation=-1} is that @code{--switch-generation} will
1861 not make a zeroth generation, so if a specified generation does not
1862 exist, the current generation will not be changed.
1864 @item --search-paths[=@var{kind}]
1865 @cindex search paths
1866 Report environment variable definitions, in Bash syntax, that may be
1867 needed in order to use the set of installed packages. These environment
1868 variables are used to specify @dfn{search paths} for files used by some
1869 of the installed packages.
1871 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1872 environment variables to be defined so it can look for headers and
1873 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1874 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1875 library are installed in the profile, then @code{--search-paths} will
1876 suggest setting these variables to @code{@var{profile}/include} and
1877 @code{@var{profile}/lib}, respectively.
1879 The typical use case is to define these environment variables in the
1883 $ eval `guix package --search-paths`
1886 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1887 meaning that the returned environment variable definitions will either
1888 be exact settings, or prefixes or suffixes of the current value of these
1889 variables. When omitted, @var{kind} defaults to @code{exact}.
1891 This option can also be used to compute the @emph{combined} search paths
1892 of several profiles. Consider this example:
1895 $ guix package -p foo -i guile
1896 $ guix package -p bar -i guile-json
1897 $ guix package -p foo -p bar --search-paths
1900 The last command above reports about the @code{GUILE_LOAD_PATH}
1901 variable, even though, taken individually, neither @file{foo} nor
1902 @file{bar} would lead to that recommendation.
1905 @item --profile=@var{profile}
1906 @itemx -p @var{profile}
1907 Use @var{profile} instead of the user's default profile.
1910 Produce verbose output. In particular, emit the build log of the
1911 environment on the standard error port.
1914 Use the bootstrap Guile to build the profile. This option is only
1915 useful to distribution developers.
1919 In addition to these actions, @command{guix package} supports the
1920 following options to query the current state of a profile, or the
1921 availability of packages:
1925 @item --search=@var{regexp}
1926 @itemx -s @var{regexp}
1927 @cindex searching for packages
1928 List the available packages whose name, synopsis, or description matches
1929 @var{regexp}, sorted by relevance. Print all the metadata of matching packages in
1930 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1931 GNU recutils manual}).
1933 This allows specific fields to be extracted using the @command{recsel}
1934 command, for instance:
1937 $ guix package -s malloc | recsel -p name,version,relevance
1951 Similarly, to show the name of all the packages available under the
1952 terms of the GNU@tie{}LGPL version 3:
1955 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1962 It is also possible to refine search results using several @code{-s}
1963 flags. For example, the following command returns a list of board
1967 $ guix package -s '\<board\>' -s game | recsel -p name
1972 If we were to omit @code{-s game}, we would also get software packages
1973 that deal with printed circuit boards; removing the angle brackets
1974 around @code{board} would further add packages that have to do with
1977 And now for a more elaborate example. The following command searches
1978 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1979 libraries, and prints the name and synopsis of the matching packages:
1982 $ guix package -s crypto -s library | \
1983 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1987 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1988 information on @dfn{selection expressions} for @code{recsel -e}.
1990 @item --show=@var{package}
1991 Show details about @var{package}, taken from the list of available packages, in
1992 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1996 $ guix package --show=python | recsel -p name,version
2004 You may also specify the full name of a package to only get details about a
2005 specific version of it:
2007 $ guix package --show=python@@3.4 | recsel -p name,version
2014 @item --list-installed[=@var{regexp}]
2015 @itemx -I [@var{regexp}]
2016 List the currently installed packages in the specified profile, with the
2017 most recently installed packages shown last. When @var{regexp} is
2018 specified, list only installed packages whose name matches @var{regexp}.
2020 For each installed package, print the following items, separated by
2021 tabs: the package name, its version string, the part of the package that
2022 is installed (for instance, @code{out} for the default output,
2023 @code{include} for its headers, etc.), and the path of this package in
2026 @item --list-available[=@var{regexp}]
2027 @itemx -A [@var{regexp}]
2028 List packages currently available in the distribution for this system
2029 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
2030 installed packages whose name matches @var{regexp}.
2032 For each package, print the following items separated by tabs: its name,
2033 its version string, the parts of the package (@pxref{Packages with
2034 Multiple Outputs}), and the source location of its definition.
2036 @item --list-generations[=@var{pattern}]
2037 @itemx -l [@var{pattern}]
2039 Return a list of generations along with their creation dates; for each
2040 generation, show the installed packages, with the most recently
2041 installed packages shown last. Note that the zeroth generation is never
2044 For each installed package, print the following items, separated by
2045 tabs: the name of a package, its version string, the part of the package
2046 that is installed (@pxref{Packages with Multiple Outputs}), and the
2047 location of this package in the store.
2049 When @var{pattern} is used, the command returns only matching
2050 generations. Valid patterns include:
2053 @item @emph{Integers and comma-separated integers}. Both patterns denote
2054 generation numbers. For instance, @code{--list-generations=1} returns
2057 And @code{--list-generations=1,8,2} outputs three generations in the
2058 specified order. Neither spaces nor trailing commas are allowed.
2060 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
2061 specified generations and everything in between. Note that the start of
2062 a range must be smaller than its end.
2064 It is also possible to omit the endpoint. For example,
2065 @code{--list-generations=2..}, returns all generations starting from the
2068 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
2069 or months by passing an integer along with the first letter of the
2070 duration. For example, @code{--list-generations=20d} lists generations
2071 that are up to 20 days old.
2074 @item --delete-generations[=@var{pattern}]
2075 @itemx -d [@var{pattern}]
2076 When @var{pattern} is omitted, delete all generations except the current
2079 This command accepts the same patterns as @option{--list-generations}.
2080 When @var{pattern} is specified, delete the matching generations. When
2081 @var{pattern} specifies a duration, generations @emph{older} than the
2082 specified duration match. For instance, @code{--delete-generations=1m}
2083 deletes generations that are more than one month old.
2085 If the current generation matches, it is @emph{not} deleted. Also, the
2086 zeroth generation is never deleted.
2088 Note that deleting generations prevents rolling back to them.
2089 Consequently, this command must be used with care.
2093 Finally, since @command{guix package} may actually start build
2094 processes, it supports all the common build options (@pxref{Common Build
2095 Options}). It also supports package transformation options, such as
2096 @option{--with-source} (@pxref{Package Transformation Options}).
2097 However, note that package transformations are lost when upgrading; to
2098 preserve transformations across upgrades, you should define your own
2099 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
2100 (@pxref{Defining Packages}).
2104 @section Substitutes
2107 @cindex pre-built binaries
2108 Guix supports transparent source/binary deployment, which means that it
2109 can either build things locally, or download pre-built items from a
2110 server. We call these pre-built items @dfn{substitutes}---they are
2111 substitutes for local build results. In many cases, downloading a
2112 substitute is much faster than building things locally.
2114 Substitutes can be anything resulting from a derivation build
2115 (@pxref{Derivations}). Of course, in the common case, they are
2116 pre-built package binaries, but source tarballs, for instance, which
2117 also result from derivation builds, can be available as substitutes.
2119 The @code{hydra.gnu.org} server is a front-end to a build farm that
2120 builds packages from the GNU distribution continuously for some
2121 architectures, and makes them available as substitutes. This is the
2122 default source of substitutes; it can be overridden by passing the
2123 @option{--substitute-urls} option either to @command{guix-daemon}
2124 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2125 or to client tools such as @command{guix package}
2126 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2129 Substitute URLs can be either HTTP or HTTPS.
2130 HTTPS is recommended because communications are encrypted; conversely,
2131 using HTTP makes all communications visible to an eavesdropper, who
2132 could use the information gathered to determine, for instance, whether
2133 your system has unpatched security vulnerabilities.
2136 @cindex digital signatures
2137 @cindex substitutes, authorization thereof
2138 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2140 must add its public key to the access control list (ACL) of archive
2141 imports, using the @command{guix archive} command (@pxref{Invoking guix
2142 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2143 be compromised and to serve genuine substitutes.
2145 This public key is installed along with Guix, in
2146 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2147 the installation prefix of Guix. If you installed Guix from source,
2148 make sure you checked the GPG signature of
2149 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2150 Then, you can run something like this:
2153 # guix archive --authorize < hydra.gnu.org.pub
2156 Once this is in place, the output of a command like @code{guix build}
2157 should change from something like:
2160 $ guix build emacs --dry-run
2161 The following derivations would be built:
2162 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2163 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2164 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2165 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2173 $ guix build emacs --dry-run
2174 The following files would be downloaded:
2175 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2176 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2177 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2178 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2183 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2184 will be downloaded, when possible, for future builds.
2186 Guix ignores substitutes that are not signed, or that are not signed by
2187 one of the keys listed in the ACL. It also detects and raises an error
2188 when attempting to use a substitute that has been tampered with.
2191 Substitutes are downloaded over HTTP or HTTPS.
2192 The @code{http_proxy} environment
2193 variable can be set in the environment of @command{guix-daemon} and is
2194 honored for downloads of substitutes. Note that the value of
2195 @code{http_proxy} in the environment where @command{guix build},
2196 @command{guix package}, and other client commands are run has
2197 @emph{absolutely no effect}.
2199 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2200 (in other words, the server is not authenticated), contrary to what
2201 HTTPS clients such as Web browsers usually do. This is because Guix
2202 authenticates substitute information itself, as explained above, which
2203 is what we care about (whereas X.509 certificates are about
2204 authenticating bindings between domain names and public keys.)
2206 You can get statistics on the substitutes provided by a server using the
2207 @command{guix weather} command (@pxref{Invoking guix weather}).
2209 The substitute mechanism can be disabled globally by running
2210 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2211 guix-daemon}). It can also be disabled temporarily by passing the
2212 @code{--no-substitutes} option to @command{guix package}, @command{guix
2213 build}, and other command-line tools.
2216 @unnumberedsubsec On Trusting Binaries
2218 Today, each individual's control over their own computing is at the
2219 mercy of institutions, corporations, and groups with enough power and
2220 determination to subvert the computing infrastructure and exploit its
2221 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2222 convenient, we encourage users to also build on their own, or even run
2223 their own build farm, such that @code{hydra.gnu.org} is less of an
2224 interesting target. One way to help is by publishing the software you
2225 build using @command{guix publish} so that others have one more choice
2226 of server to download substitutes from (@pxref{Invoking guix publish}).
2228 Guix has the foundations to maximize build reproducibility
2229 (@pxref{Features}). In most cases, independent builds of a given
2230 package or derivation should yield bit-identical results. Thus, through
2231 a diverse set of independent package builds, we can strengthen the
2232 integrity of our systems. The @command{guix challenge} command aims to
2233 help users assess substitute servers, and to assist developers in
2234 finding out about non-deterministic package builds (@pxref{Invoking guix
2235 challenge}). Similarly, the @option{--check} option of @command{guix
2236 build} allows users to check whether previously-installed substitutes
2237 are genuine by rebuilding them locally (@pxref{build-check,
2238 @command{guix build --check}}).
2240 In the future, we want Guix to have support to publish and retrieve
2241 binaries to/from other users, in a peer-to-peer fashion. If you would
2242 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2245 @node Packages with Multiple Outputs
2246 @section Packages with Multiple Outputs
2248 @cindex multiple-output packages
2249 @cindex package outputs
2252 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2253 source package leads to exactly one directory in the store. When running
2254 @command{guix package -i glibc}, one installs the default output of the
2255 GNU libc package; the default output is called @code{out}, but its name
2256 can be omitted as shown in this command. In this particular case, the
2257 default output of @code{glibc} contains all the C header files, shared
2258 libraries, static libraries, Info documentation, and other supporting
2261 Sometimes it is more appropriate to separate the various types of files
2262 produced from a single source package into separate outputs. For
2263 instance, the GLib C library (used by GTK+ and related packages)
2264 installs more than 20 MiB of reference documentation as HTML pages.
2265 To save space for users who do not need it, the documentation goes to a
2266 separate output, called @code{doc}. To install the main GLib output,
2267 which contains everything but the documentation, one would run:
2270 guix package -i glib
2273 @cindex documentation
2274 The command to install its documentation is:
2277 guix package -i glib:doc
2280 Some packages install programs with different ``dependency footprints''.
2281 For instance, the WordNet package installs both command-line tools and
2282 graphical user interfaces (GUIs). The former depend solely on the C
2283 library, whereas the latter depend on Tcl/Tk and the underlying X
2284 libraries. In this case, we leave the command-line tools in the default
2285 output, whereas the GUIs are in a separate output. This allows users
2286 who do not need the GUIs to save space. The @command{guix size} command
2287 can help find out about such situations (@pxref{Invoking guix size}).
2288 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2290 There are several such multiple-output packages in the GNU distribution.
2291 Other conventional output names include @code{lib} for libraries and
2292 possibly header files, @code{bin} for stand-alone programs, and
2293 @code{debug} for debugging information (@pxref{Installing Debugging
2294 Files}). The outputs of a packages are listed in the third column of
2295 the output of @command{guix package --list-available} (@pxref{Invoking
2299 @node Invoking guix gc
2300 @section Invoking @command{guix gc}
2302 @cindex garbage collector
2304 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2305 The @command{guix gc} command allows users to explicitly run the garbage
2306 collector to reclaim space from the @file{/gnu/store} directory. It is
2307 the @emph{only} way to remove files from @file{/gnu/store}---removing
2308 files or directories manually may break it beyond repair!
2310 The garbage collector has a set of known @dfn{roots}: any file under
2311 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2312 cannot be deleted; any other file is considered @dfn{dead} and may be
2313 deleted. The set of garbage collector roots includes default user
2314 profiles, and may be augmented with @command{guix build --root}, for
2315 example (@pxref{Invoking guix build}).
2317 Prior to running @code{guix gc --collect-garbage} to make space, it is
2318 often useful to remove old generations from user profiles; that way, old
2319 package builds referenced by those generations can be reclaimed. This
2320 is achieved by running @code{guix package --delete-generations}
2321 (@pxref{Invoking guix package}).
2323 Our recommendation is to run a garbage collection periodically, or when
2324 you are short on disk space. For instance, to guarantee that at least
2325 5@tie{}GB are available on your disk, simply run:
2331 It is perfectly safe to run as a non-interactive periodic job
2332 (@pxref{Scheduled Job Execution}, for how to set up such a job on
2333 GuixSD). Running @command{guix gc} with no arguments will collect as
2334 much garbage as it can, but that is often inconvenient: you may find
2335 yourself having to rebuild or re-download software that is ``dead'' from
2336 the GC viewpoint but that is necessary to build other pieces of
2337 software---e.g., the compiler tool chain.
2339 The @command{guix gc} command has three modes of operation: it can be
2340 used to garbage-collect any dead files (the default), to delete specific
2341 files (the @code{--delete} option), to print garbage-collector
2342 information, or for more advanced queries. The garbage collection
2343 options are as follows:
2346 @item --collect-garbage[=@var{min}]
2347 @itemx -C [@var{min}]
2348 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2349 sub-directories. This is the default operation when no option is
2352 When @var{min} is given, stop once @var{min} bytes have been collected.
2353 @var{min} may be a number of bytes, or it may include a unit as a
2354 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2355 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2357 When @var{min} is omitted, collect all the garbage.
2359 @item --free-space=@var{free}
2360 @itemx -F @var{free}
2361 Collect garbage until @var{free} space is available under
2362 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2363 as @code{500MiB}, as described above.
2365 When @var{free} or more is already available in @file{/gnu/store}, do
2366 nothing and exit immediately.
2370 Attempt to delete all the store files and directories specified as
2371 arguments. This fails if some of the files are not in the store, or if
2372 they are still live.
2374 @item --list-failures
2375 List store items corresponding to cached build failures.
2377 This prints nothing unless the daemon was started with
2378 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2379 @option{--cache-failures}}).
2381 @item --clear-failures
2382 Remove the specified store items from the failed-build cache.
2384 Again, this option only makes sense when the daemon is started with
2385 @option{--cache-failures}. Otherwise, it does nothing.
2388 Show the list of dead files and directories still present in the
2389 store---i.e., files and directories no longer reachable from any root.
2392 Show the list of live store files and directories.
2396 In addition, the references among existing store files can be queried:
2402 @cindex package dependencies
2403 List the references (respectively, the referrers) of store files given
2409 List the requisites of the store files passed as arguments. Requisites
2410 include the store files themselves, their references, and the references
2411 of these, recursively. In other words, the returned list is the
2412 @dfn{transitive closure} of the store files.
2414 @xref{Invoking guix size}, for a tool to profile the size of the closure
2415 of an element. @xref{Invoking guix graph}, for a tool to visualize
2416 the graph of references.
2420 Lastly, the following options allow you to check the integrity of the
2421 store and to control disk usage.
2425 @item --verify[=@var{options}]
2426 @cindex integrity, of the store
2427 @cindex integrity checking
2428 Verify the integrity of the store.
2430 By default, make sure that all the store items marked as valid in the
2431 database of the daemon actually exist in @file{/gnu/store}.
2433 When provided, @var{options} must be a comma-separated list containing one
2434 or more of @code{contents} and @code{repair}.
2436 When passing @option{--verify=contents}, the daemon computes the
2437 content hash of each store item and compares it against its hash in the
2438 database. Hash mismatches are reported as data corruptions. Because it
2439 traverses @emph{all the files in the store}, this command can take a
2440 long time, especially on systems with a slow disk drive.
2442 @cindex repairing the store
2443 @cindex corruption, recovering from
2444 Using @option{--verify=repair} or @option{--verify=contents,repair}
2445 causes the daemon to try to repair corrupt store items by fetching
2446 substitutes for them (@pxref{Substitutes}). Because repairing is not
2447 atomic, and thus potentially dangerous, it is available only to the
2448 system administrator. A lightweight alternative, when you know exactly
2449 which items in the store are corrupt, is @command{guix build --repair}
2450 (@pxref{Invoking guix build}).
2453 @cindex deduplication
2454 Optimize the store by hard-linking identical files---this is
2455 @dfn{deduplication}.
2457 The daemon performs deduplication after each successful build or archive
2458 import, unless it was started with @code{--disable-deduplication}
2459 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2460 this option is primarily useful when the daemon was running with
2461 @code{--disable-deduplication}.
2465 @node Invoking guix pull
2466 @section Invoking @command{guix pull}
2468 @cindex upgrading Guix
2469 @cindex updating Guix
2470 @cindex @command{guix pull}
2472 Packages are installed or upgraded to the latest version available in
2473 the distribution currently available on your local machine. To update
2474 that distribution, along with the Guix tools, you must run @command{guix
2475 pull}: the command downloads the latest Guix source code and package
2476 descriptions, and deploys it.
2478 On completion, @command{guix package} will use packages and package
2479 versions from this just-retrieved copy of Guix. Not only that, but all
2480 the Guix commands and Scheme modules will also be taken from that latest
2481 version. New @command{guix} sub-commands added by the update also
2484 Any user can update their Guix copy using @command{guix pull}, and the
2485 effect is limited to the user who run @command{guix pull}. For
2486 instance, when user @code{root} runs @command{guix pull}, this has no
2487 effect on the version of Guix that user @code{alice} sees, and vice
2488 versa@footnote{Under the hood, @command{guix pull} updates the
2489 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2490 and the @command{guix} command loads code from there. Currently, the
2491 only way to roll back an invocation of @command{guix pull} is to
2492 manually update this symlink to point to the previous Guix.}.
2494 The @command{guix pull} command is usually invoked with no arguments,
2495 but it supports the following options:
2499 Produce verbose output, writing build logs to the standard error output.
2501 @item --url=@var{url}
2502 Download the source tarball of Guix from @var{url}.
2504 By default, the tarball is taken from its canonical address at
2505 @code{gnu.org}, for the stable branch of Guix.
2507 With some Git servers, this can be used to deploy any version of Guix.
2508 For example, to download and deploy version 0.12.0 of Guix from the
2512 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.12.0.tar.gz
2515 It can also be used to deploy arbitrary Git revisions:
2518 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/74d862e8a.tar.gz
2522 Use the bootstrap Guile to build the latest Guix. This option is only
2523 useful to Guix developers.
2526 In addition, @command{guix pull} supports all the common build options
2527 (@pxref{Common Build Options}).
2529 @node Invoking guix pack
2530 @section Invoking @command{guix pack}
2532 Occasionally you want to pass software to people who are not (yet!)
2533 lucky enough to be using Guix. You'd tell them to run @command{guix
2534 package -i @var{something}}, but that's not possible in this case. This
2535 is where @command{guix pack} comes in.
2539 @cindex application bundle
2540 @cindex software bundle
2541 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2542 @dfn{software bundle}: it creates a tarball or some other archive
2543 containing the binaries of the software you're interested in, and all
2544 its dependencies. The resulting archive can be used on any machine that
2545 does not have Guix, and people can run the exact same binaries as those
2546 you have with Guix. The pack itself is created in a bit-reproducible
2547 fashion, so anyone can verify that it really contains the build results
2548 that you pretend to be shipping.
2550 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2551 their dependencies, you can run:
2554 $ guix pack guile emacs geiser
2556 /gnu/store/@dots{}-pack.tar.gz
2559 The result here is a tarball containing a @file{/gnu/store} directory
2560 with all the relevant packages. The resulting tarball contains a
2561 @dfn{profile} with the three packages of interest; the profile is the
2562 same as would be created by @command{guix package -i}. It is this
2563 mechanism that is used to create Guix's own standalone binary tarball
2564 (@pxref{Binary Installation}).
2566 Users of this pack would have to run
2567 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2568 find inconvenient. To work around it, you can create, say, a
2569 @file{/opt/gnu/bin} symlink to the profile:
2572 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2576 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2578 Alternatively, you can produce a pack in the Docker image format using
2579 the following command:
2582 guix pack -f docker guile emacs geiser
2586 The result is a tarball that can be passed to the @command{docker load}
2588 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2589 documentation} for more information.
2591 Several command-line options allow you to customize your pack:
2594 @item --format=@var{format}
2595 @itemx -f @var{format}
2596 Produce a pack in the given @var{format}.
2598 The available formats are:
2602 This is the default format. It produces a tarball containing all the
2603 specifies binaries and symlinks.
2606 This produces a tarball that follows the
2607 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2608 Docker Image Specification}.
2611 @item --expression=@var{expr}
2612 @itemx -e @var{expr}
2613 Consider the package @var{expr} evaluates to.
2615 This has the same purpose as the same-named option in @command{guix
2616 build} (@pxref{Additional Build Options, @code{--expression} in
2617 @command{guix build}}).
2619 @item --system=@var{system}
2620 @itemx -s @var{system}
2621 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2622 the system type of the build host.
2624 @item --target=@var{triplet}
2625 @cindex cross-compilation
2626 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2627 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2628 configuration triplets,, autoconf, Autoconf}).
2630 @item --compression=@var{tool}
2631 @itemx -C @var{tool}
2632 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2633 @code{bzip2}, @code{xz}, or @code{lzip}.
2635 @item --symlink=@var{spec}
2636 @itemx -S @var{spec}
2637 Add the symlinks specified by @var{spec} to the pack. This option can
2638 appear several times.
2640 @var{spec} has the form @code{@var{source}=@var{target}}, where
2641 @var{source} is the symlink that will be created and @var{target} is the
2644 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2645 symlink pointing to the @file{bin} sub-directory of the profile.
2647 @item --localstatedir
2648 Include the ``local state directory'', @file{/var/guix}, in the
2651 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2652 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2653 the pack means that the store is ``complete'' and manageable by Guix;
2654 not providing it pack means that the store is ``dead'': items cannot be
2655 added to it or removed from it after extraction of the pack.
2657 One use case for this is the Guix self-contained binary tarball
2658 (@pxref{Binary Installation}).
2661 In addition, @command{guix pack} supports all the common build options
2662 (@pxref{Common Build Options}) and all the package transformation
2663 options (@pxref{Package Transformation Options}).
2666 @node Invoking guix archive
2667 @section Invoking @command{guix archive}
2669 @cindex @command{guix archive}
2671 The @command{guix archive} command allows users to @dfn{export} files
2672 from the store into a single archive, and to later @dfn{import} them.
2673 In particular, it allows store files to be transferred from one machine
2674 to the store on another machine.
2676 @cindex exporting store items
2677 To export store files as an archive to standard output, run:
2680 guix archive --export @var{options} @var{specifications}...
2683 @var{specifications} may be either store file names or package
2684 specifications, as for @command{guix package} (@pxref{Invoking guix
2685 package}). For instance, the following command creates an archive
2686 containing the @code{gui} output of the @code{git} package and the main
2687 output of @code{emacs}:
2690 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2693 If the specified packages are not built yet, @command{guix archive}
2694 automatically builds them. The build process may be controlled with the
2695 common build options (@pxref{Common Build Options}).
2697 To transfer the @code{emacs} package to a machine connected over SSH,
2701 guix archive --export -r emacs | ssh the-machine guix archive --import
2705 Similarly, a complete user profile may be transferred from one machine
2706 to another like this:
2709 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2710 ssh the-machine guix-archive --import
2714 However, note that, in both examples, all of @code{emacs} and the
2715 profile as well as all of their dependencies are transferred (due to
2716 @code{-r}), regardless of what is already available in the store on the
2717 target machine. The @code{--missing} option can help figure out which
2718 items are missing from the target store. The @command{guix copy}
2719 command simplifies and optimizes this whole process, so this is probably
2720 what you should use in this case (@pxref{Invoking guix copy}).
2722 @cindex nar, archive format
2723 @cindex normalized archive (nar)
2724 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2725 comparable in spirit to `tar', but with differences
2726 that make it more appropriate for our purposes. First, rather than
2727 recording all Unix metadata for each file, the nar format only mentions
2728 the file type (regular, directory, or symbolic link); Unix permissions
2729 and owner/group are dismissed. Second, the order in which directory
2730 entries are stored always follows the order of file names according to
2731 the C locale collation order. This makes archive production fully
2734 When exporting, the daemon digitally signs the contents of the archive,
2735 and that digital signature is appended. When importing, the daemon
2736 verifies the signature and rejects the import in case of an invalid
2737 signature or if the signing key is not authorized.
2738 @c FIXME: Add xref to daemon doc about signatures.
2740 The main options are:
2744 Export the specified store files or packages (see below.) Write the
2745 resulting archive to the standard output.
2747 Dependencies are @emph{not} included in the output, unless
2748 @code{--recursive} is passed.
2752 When combined with @code{--export}, this instructs @command{guix
2753 archive} to include dependencies of the given items in the archive.
2754 Thus, the resulting archive is self-contained: it contains the closure
2755 of the exported store items.
2758 Read an archive from the standard input, and import the files listed
2759 therein into the store. Abort if the archive has an invalid digital
2760 signature, or if it is signed by a public key not among the authorized
2761 keys (see @code{--authorize} below.)
2764 Read a list of store file names from the standard input, one per line,
2765 and write on the standard output the subset of these files missing from
2768 @item --generate-key[=@var{parameters}]
2769 @cindex signing, archives
2770 Generate a new key pair for the daemon. This is a prerequisite before
2771 archives can be exported with @code{--export}. Note that this operation
2772 usually takes time, because it needs to gather enough entropy to
2773 generate the key pair.
2775 The generated key pair is typically stored under @file{/etc/guix}, in
2776 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2777 key, which must be kept secret.) When @var{parameters} is omitted,
2778 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2779 versions before 1.6.0, it is a 4096-bit RSA key.
2780 Alternatively, @var{parameters} can specify
2781 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2782 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2783 Libgcrypt Reference Manual}).
2786 @cindex authorizing, archives
2787 Authorize imports signed by the public key passed on standard input.
2788 The public key must be in ``s-expression advanced format''---i.e., the
2789 same format as the @file{signing-key.pub} file.
2791 The list of authorized keys is kept in the human-editable file
2792 @file{/etc/guix/acl}. The file contains
2793 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2794 s-expressions''} and is structured as an access-control list in the
2795 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2798 @item --extract=@var{directory}
2799 @itemx -x @var{directory}
2800 Read a single-item archive as served by substitute servers
2801 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2802 low-level operation needed in only very narrow use cases; see below.
2804 For example, the following command extracts the substitute for Emacs
2805 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2809 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2810 | bunzip2 | guix archive -x /tmp/emacs
2813 Single-item archives are different from multiple-item archives produced
2814 by @command{guix archive --export}; they contain a single store item,
2815 and they do @emph{not} embed a signature. Thus this operation does
2816 @emph{no} signature verification and its output should be considered
2819 The primary purpose of this operation is to facilitate inspection of
2820 archive contents coming from possibly untrusted substitute servers.
2824 @c *********************************************************************
2825 @node Programming Interface
2826 @chapter Programming Interface
2828 GNU Guix provides several Scheme programming interfaces (APIs) to
2829 define, build, and query packages. The first interface allows users to
2830 write high-level package definitions. These definitions refer to
2831 familiar packaging concepts, such as the name and version of a package,
2832 its build system, and its dependencies. These definitions can then be
2833 turned into concrete build actions.
2835 Build actions are performed by the Guix daemon, on behalf of users. In a
2836 standard setup, the daemon has write access to the store---the
2837 @file{/gnu/store} directory---whereas users do not. The recommended
2838 setup also has the daemon perform builds in chroots, under a specific
2839 build users, to minimize interference with the rest of the system.
2842 Lower-level APIs are available to interact with the daemon and the
2843 store. To instruct the daemon to perform a build action, users actually
2844 provide it with a @dfn{derivation}. A derivation is a low-level
2845 representation of the build actions to be taken, and the environment in
2846 which they should occur---derivations are to package definitions what
2847 assembly is to C programs. The term ``derivation'' comes from the fact
2848 that build results @emph{derive} from them.
2850 This chapter describes all these APIs in turn, starting from high-level
2851 package definitions.
2854 * Defining Packages:: Defining new packages.
2855 * Build Systems:: Specifying how packages are built.
2856 * The Store:: Manipulating the package store.
2857 * Derivations:: Low-level interface to package derivations.
2858 * The Store Monad:: Purely functional interface to the store.
2859 * G-Expressions:: Manipulating build expressions.
2862 @node Defining Packages
2863 @section Defining Packages
2865 The high-level interface to package definitions is implemented in the
2866 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2867 example, the package definition, or @dfn{recipe}, for the GNU Hello
2868 package looks like this:
2871 (define-module (gnu packages hello)
2872 #:use-module (guix packages)
2873 #:use-module (guix download)
2874 #:use-module (guix build-system gnu)
2875 #:use-module (guix licenses)
2876 #:use-module (gnu packages gawk))
2878 (define-public hello
2884 (uri (string-append "mirror://gnu/hello/hello-" version
2888 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2889 (build-system gnu-build-system)
2890 (arguments '(#:configure-flags '("--enable-silent-rules")))
2891 (inputs `(("gawk" ,gawk)))
2892 (synopsis "Hello, GNU world: An example GNU package")
2893 (description "Guess what GNU Hello prints!")
2894 (home-page "http://www.gnu.org/software/hello/")
2899 Without being a Scheme expert, the reader may have guessed the meaning
2900 of the various fields here. This expression binds the variable
2901 @code{hello} to a @code{<package>} object, which is essentially a record
2902 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2903 This package object can be inspected using procedures found in the
2904 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2905 returns---surprise!---@code{"hello"}.
2907 With luck, you may be able to import part or all of the definition of
2908 the package you are interested in from another repository, using the
2909 @code{guix import} command (@pxref{Invoking guix import}).
2911 In the example above, @var{hello} is defined in a module of its own,
2912 @code{(gnu packages hello)}. Technically, this is not strictly
2913 necessary, but it is convenient to do so: all the packages defined in
2914 modules under @code{(gnu packages @dots{})} are automatically known to
2915 the command-line tools (@pxref{Package Modules}).
2917 There are a few points worth noting in the above package definition:
2921 The @code{source} field of the package is an @code{<origin>} object
2922 (@pxref{origin Reference}, for the complete reference).
2923 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2924 meaning that the source is a file to be downloaded over FTP or HTTP.
2926 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2927 the GNU mirrors defined in @code{(guix download)}.
2929 The @code{sha256} field specifies the expected SHA256 hash of the file
2930 being downloaded. It is mandatory, and allows Guix to check the
2931 integrity of the file. The @code{(base32 @dots{})} form introduces the
2932 base32 representation of the hash. You can obtain this information with
2933 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2934 hash} (@pxref{Invoking guix hash}).
2937 When needed, the @code{origin} form can also have a @code{patches} field
2938 listing patches to be applied, and a @code{snippet} field giving a
2939 Scheme expression to modify the source code.
2942 @cindex GNU Build System
2943 The @code{build-system} field specifies the procedure to build the
2944 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2945 represents the familiar GNU Build System, where packages may be
2946 configured, built, and installed with the usual @code{./configure &&
2947 make && make check && make install} command sequence.
2950 The @code{arguments} field specifies options for the build system
2951 (@pxref{Build Systems}). Here it is interpreted by
2952 @var{gnu-build-system} as a request run @file{configure} with the
2953 @code{--enable-silent-rules} flag.
2959 What about these quote (@code{'}) characters? They are Scheme syntax to
2960 introduce a literal list; @code{'} is synonymous with @code{quote}.
2961 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2962 for details. Here the value of the @code{arguments} field is a list of
2963 arguments passed to the build system down the road, as with @code{apply}
2964 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2967 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2968 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2969 @code{#:configure-flags} is a keyword used to pass a keyword argument
2970 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2974 The @code{inputs} field specifies inputs to the build process---i.e.,
2975 build-time or run-time dependencies of the package. Here, we define an
2976 input called @code{"gawk"} whose value is that of the @var{gawk}
2977 variable; @var{gawk} is itself bound to a @code{<package>} object.
2979 @cindex backquote (quasiquote)
2982 @cindex comma (unquote)
2986 @findex unquote-splicing
2987 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2988 us to introduce a literal list in the @code{inputs} field, while
2989 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2990 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2993 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2994 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2995 of ensuring that they are present (@pxref{Build Systems}).
2997 However, any other dependencies need to be specified in the
2998 @code{inputs} field. Any dependency not specified here will simply be
2999 unavailable to the build process, possibly leading to a build failure.
3002 @xref{package Reference}, for a full description of possible fields.
3004 Once a package definition is in place, the
3005 package may actually be built using the @code{guix build} command-line
3006 tool (@pxref{Invoking guix build}), troubleshooting any build failures
3007 you encounter (@pxref{Debugging Build Failures}). You can easily jump back to the
3008 package definition using the @command{guix edit} command
3009 (@pxref{Invoking guix edit}).
3010 @xref{Packaging Guidelines}, for
3011 more information on how to test package definitions, and
3012 @ref{Invoking guix lint}, for information on how to check a definition
3013 for style conformance.
3014 @vindex GUIX_PACKAGE_PATH
3015 Lastly, @pxref{Package Modules}, for information
3016 on how to extend the distribution by adding your own package definitions
3017 to @code{GUIX_PACKAGE_PATH}.
3019 Finally, updating the package definition to a new upstream version
3020 can be partly automated by the @command{guix refresh} command
3021 (@pxref{Invoking guix refresh}).
3023 Behind the scenes, a derivation corresponding to the @code{<package>}
3024 object is first computed by the @code{package-derivation} procedure.
3025 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
3026 The build actions it prescribes may then be realized by using the
3027 @code{build-derivations} procedure (@pxref{The Store}).
3029 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
3030 Return the @code{<derivation>} object of @var{package} for @var{system}
3031 (@pxref{Derivations}).
3033 @var{package} must be a valid @code{<package>} object, and @var{system}
3034 must be a string denoting the target system type---e.g.,
3035 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
3036 must be a connection to the daemon, which operates on the store
3037 (@pxref{The Store}).
3041 @cindex cross-compilation
3042 Similarly, it is possible to compute a derivation that cross-builds a
3043 package for some other system:
3045 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
3046 @var{package} @var{target} [@var{system}]
3047 Return the @code{<derivation>} object of @var{package} cross-built from
3048 @var{system} to @var{target}.
3050 @var{target} must be a valid GNU triplet denoting the target hardware
3051 and operating system, such as @code{"mips64el-linux-gnu"}
3052 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
3053 Configure and Build System}).
3056 @cindex package transformations
3057 @cindex input rewriting
3058 @cindex dependency tree rewriting
3059 Packages can be manipulated in arbitrary ways. An example of a useful
3060 transformation is @dfn{input rewriting}, whereby the dependency tree of
3061 a package is rewritten by replacing specific inputs by others:
3063 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
3064 [@var{rewrite-name}]
3065 Return a procedure that, when passed a package, replaces its direct and
3066 indirect dependencies (but not its implicit inputs) according to
3067 @var{replacements}. @var{replacements} is a list of package pairs; the
3068 first element of each pair is the package to replace, and the second one
3071 Optionally, @var{rewrite-name} is a one-argument procedure that takes
3072 the name of a package and returns its new name after rewrite.
3076 Consider this example:
3079 (define libressl-instead-of-openssl
3080 ;; This is a procedure to replace OPENSSL by LIBRESSL,
3082 (package-input-rewriting `((,openssl . ,libressl))))
3084 (define git-with-libressl
3085 (libressl-instead-of-openssl git))
3089 Here we first define a rewriting procedure that replaces @var{openssl}
3090 with @var{libressl}. Then we use it to define a @dfn{variant} of the
3091 @var{git} package that uses @var{libressl} instead of @var{openssl}.
3092 This is exactly what the @option{--with-input} command-line option does
3093 (@pxref{Package Transformation Options, @option{--with-input}}).
3095 A more generic procedure to rewrite a package dependency graph is
3096 @code{package-mapping}: it supports arbitrary changes to nodes in the
3099 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
3100 Return a procedure that, given a package, applies @var{proc} to all the packages
3101 depended on and returns the resulting package. The procedure stops recursion
3102 when @var{cut?} returns true for a given package.
3106 * package Reference :: The package data type.
3107 * origin Reference:: The origin data type.
3111 @node package Reference
3112 @subsection @code{package} Reference
3114 This section summarizes all the options available in @code{package}
3115 declarations (@pxref{Defining Packages}).
3117 @deftp {Data Type} package
3118 This is the data type representing a package recipe.
3122 The name of the package, as a string.
3124 @item @code{version}
3125 The version of the package, as a string.
3128 An object telling how the source code for the package should be
3129 acquired. Most of the time, this is an @code{origin} object, which
3130 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3131 can also be any other ``file-like'' object such as a @code{local-file},
3132 which denotes a file from the local file system (@pxref{G-Expressions,
3133 @code{local-file}}).
3135 @item @code{build-system}
3136 The build system that should be used to build the package (@pxref{Build
3139 @item @code{arguments} (default: @code{'()})
3140 The arguments that should be passed to the build system. This is a
3141 list, typically containing sequential keyword-value pairs.
3143 @item @code{inputs} (default: @code{'()})
3144 @itemx @code{native-inputs} (default: @code{'()})
3145 @itemx @code{propagated-inputs} (default: @code{'()})
3146 @cindex inputs, of packages
3147 These fields list dependencies of the package. Each one is a list of
3148 tuples, where each tuple has a label for the input (a string) as its
3149 first element, a package, origin, or derivation as its second element,
3150 and optionally the name of the output thereof that should be used, which
3151 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3152 more on package outputs). For example, the list below specifies three
3156 `(("libffi" ,libffi)
3157 ("libunistring" ,libunistring)
3158 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3161 @cindex cross compilation, package dependencies
3162 The distinction between @code{native-inputs} and @code{inputs} is
3163 necessary when considering cross-compilation. When cross-compiling,
3164 dependencies listed in @code{inputs} are built for the @emph{target}
3165 architecture; conversely, dependencies listed in @code{native-inputs}
3166 are built for the architecture of the @emph{build} machine.
3168 @code{native-inputs} is typically used to list tools needed at
3169 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3170 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3171 this area (@pxref{Invoking guix lint}).
3173 @anchor{package-propagated-inputs}
3174 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3175 specified packages will be automatically installed alongside the package
3176 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3177 package}}, for information on how @command{guix package} deals with
3180 For example this is necessary when a C/C++ library needs headers of
3181 another library to compile, or when a pkg-config file refers to another
3182 one @i{via} its @code{Requires} field.
3184 Another example where @code{propagated-inputs} is useful is for languages
3185 that lack a facility to record the run-time search path akin to the
3186 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3187 more. To ensure that libraries written in those languages can find
3188 library code they depend on at run time, run-time dependencies must be
3189 listed in @code{propagated-inputs} rather than @code{inputs}.
3191 @item @code{self-native-input?} (default: @code{#f})
3192 This is a Boolean field telling whether the package should use itself as
3193 a native input when cross-compiling.
3195 @item @code{outputs} (default: @code{'("out")})
3196 The list of output names of the package. @xref{Packages with Multiple
3197 Outputs}, for typical uses of additional outputs.
3199 @item @code{native-search-paths} (default: @code{'()})
3200 @itemx @code{search-paths} (default: @code{'()})
3201 A list of @code{search-path-specification} objects describing
3202 search-path environment variables honored by the package.
3204 @item @code{replacement} (default: @code{#f})
3205 This must be either @code{#f} or a package object that will be used as a
3206 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3209 @item @code{synopsis}
3210 A one-line description of the package.
3212 @item @code{description}
3213 A more elaborate description of the package.
3215 @item @code{license}
3216 @cindex license, of packages
3217 The license of the package; a value from @code{(guix licenses)},
3218 or a list of such values.
3220 @item @code{home-page}
3221 The URL to the home-page of the package, as a string.
3223 @item @code{supported-systems} (default: @var{%supported-systems})
3224 The list of systems supported by the package, as strings of the form
3225 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3227 @item @code{maintainers} (default: @code{'()})
3228 The list of maintainers of the package, as @code{maintainer} objects.
3230 @item @code{location} (default: source location of the @code{package} form)
3231 The source location of the package. It is useful to override this when
3232 inheriting from another package, in which case this field is not
3233 automatically corrected.
3238 @node origin Reference
3239 @subsection @code{origin} Reference
3241 This section summarizes all the options available in @code{origin}
3242 declarations (@pxref{Defining Packages}).
3244 @deftp {Data Type} origin
3245 This is the data type representing a source code origin.
3249 An object containing the URI of the source. The object type depends on
3250 the @code{method} (see below). For example, when using the
3251 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3252 values are: a URL represented as a string, or a list thereof.
3255 A procedure that handles the URI.
3260 @item @var{url-fetch} from @code{(guix download)}
3261 download a file from the HTTP, HTTPS, or FTP URL specified in the
3265 @item @var{git-fetch} from @code{(guix git-download)}
3266 clone the Git version control repository, and check out the revision
3267 specified in the @code{uri} field as a @code{git-reference} object; a
3268 @code{git-reference} looks like this:
3272 (url "git://git.debian.org/git/pkg-shadow/shadow")
3273 (commit "v4.1.5.1"))
3278 A bytevector containing the SHA-256 hash of the source. Typically the
3279 @code{base32} form is used here to generate the bytevector from a
3282 You can obtain this information using @code{guix download}
3283 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3286 @item @code{file-name} (default: @code{#f})
3287 The file name under which the source code should be saved. When this is
3288 @code{#f}, a sensible default value will be used in most cases. In case
3289 the source is fetched from a URL, the file name from the URL will be
3290 used. For version control checkouts, it is recommended to provide the
3291 file name explicitly because the default is not very descriptive.
3293 @item @code{patches} (default: @code{'()})
3294 A list of file names containing 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} ocaml-build-system
3580 This variable is exported by @code{(guix build-system ocaml)}. It implements
3581 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3582 of choosing the correct set of commands to run for each package. OCaml
3583 packages can expect many different commands to be run. This build system will
3586 When the package has a @file{setup.ml} file present at the top-level, it will
3587 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3588 @code{ocaml setup.ml -install}. The build system will assume that this file
3589 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3590 care of setting the prefix and enabling tests if they are not disabled. You
3591 can pass configure and build flags with the @code{#:configure-flags} and
3592 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3593 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3594 bypass this system in the build and install phases.
3596 When the package has a @file{configure} file, it is assumed that it is a
3597 hand-made configure script that requires a different argument format than
3598 in the @code{gnu-build-system}. You can add more flags with the
3599 @code{#:configure-flags} key.
3601 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3602 @code{#t}), it will be used and more flags can be passed to the build and
3603 install phases with the @code{#:make-flags} key.
3605 Finally, some packages do not have these files and use a somewhat standard
3606 location for its build system. In that case, the build system will run
3607 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3608 providing the path to the required findlib module. Additional flags can
3609 be passed via the @code{#:build-flags} key. Install is taken care of by
3610 @command{opam-installer}. In this case, the @code{opam} package must
3611 be added to the @code{native-inputs} field of the package definition.
3613 Note that most OCaml packages assume they will be installed in the same
3614 directory as OCaml, which is not what we want in guix. In particular, they
3615 will install @file{.so} files in their module's directory, which is usually
3616 fine because it is in the OCaml compiler directory. In guix though, these
3617 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3618 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3619 @file{.so} libraries should be installed.
3622 @defvr {Scheme Variable} python-build-system
3623 This variable is exported by @code{(guix build-system python)}. It
3624 implements the more or less standard build procedure used by Python
3625 packages, which consists in running @code{python setup.py build} and
3626 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3628 For packages that install stand-alone Python programs under @code{bin/},
3629 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3630 environment variable points to all the Python libraries they depend on.
3632 Which Python package is used to perform the build can be specified with
3633 the @code{#:python} parameter. This is a useful way to force a package
3634 to be built for a specific version of the Python interpreter, which
3635 might be necessary if the package is only compatible with a single
3636 interpreter version.
3638 By default guix calls @code{setup.py} under control of
3639 @code{setuptools}, much like @command{pip} does. Some packages are not
3640 compatible with setuptools (and pip), thus you can disable this by
3641 setting the @code{#:use-setuptools} parameter to @code{#f}.
3644 @defvr {Scheme Variable} perl-build-system
3645 This variable is exported by @code{(guix build-system perl)}. It
3646 implements the standard build procedure for Perl packages, which either
3647 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3648 followed by @code{Build} and @code{Build install}; or in running
3649 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3650 @code{make} and @code{make install}, depending on which of
3651 @code{Build.PL} or @code{Makefile.PL} is present in the package
3652 distribution. Preference is given to the former if both @code{Build.PL}
3653 and @code{Makefile.PL} exist in the package distribution. This
3654 preference can be reversed by specifying @code{#t} for the
3655 @code{#:make-maker?} parameter.
3657 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3658 passes flags specified by the @code{#:make-maker-flags} or
3659 @code{#:module-build-flags} parameter, respectively.
3661 Which Perl package is used can be specified with @code{#:perl}.
3664 @defvr {Scheme Variable} r-build-system
3665 This variable is exported by @code{(guix build-system r)}. It
3666 implements the build procedure used by @uref{http://r-project.org, R}
3667 packages, which essentially is little more than running @code{R CMD
3668 INSTALL --library=/gnu/store/@dots{}} in an environment where
3669 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3670 are run after installation using the R function
3671 @code{tools::testInstalledPackage}.
3674 @defvr {Scheme Variable} texlive-build-system
3675 This variable is exported by @code{(guix build-system texlive)}. It is
3676 used to build TeX packages in batch mode with a specified engine. The
3677 build system sets the @code{TEXINPUTS} variable to find all TeX source
3678 files in the inputs.
3680 By default it runs @code{luatex} on all files ending on @code{ins}. A
3681 different engine and format can be specified with the
3682 @code{#:tex-format} argument. Different build targets can be specified
3683 with the @code{#:build-targets} argument, which expects a list of file
3684 names. The build system adds only @code{texlive-bin} and
3685 @code{texlive-latex-base} (both from @code{(gnu packages tex}) to the
3686 inputs. Both can be overridden with the arguments @code{#:texlive-bin}
3687 and @code{#:texlive-latex-base}, respectively.
3689 The @code{#:tex-directory} parameter tells the build system where to
3690 install the built files under the texmf tree.
3693 @defvr {Scheme Variable} ruby-build-system
3694 This variable is exported by @code{(guix build-system ruby)}. It
3695 implements the RubyGems build procedure used by Ruby packages, which
3696 involves running @code{gem build} followed by @code{gem install}.
3698 The @code{source} field of a package that uses this build system
3699 typically references a gem archive, since this is the format that Ruby
3700 developers use when releasing their software. The build system unpacks
3701 the gem archive, potentially patches the source, runs the test suite,
3702 repackages the gem, and installs it. Additionally, directories and
3703 tarballs may be referenced to allow building unreleased gems from Git or
3704 a traditional source release tarball.
3706 Which Ruby package is used can be specified with the @code{#:ruby}
3707 parameter. A list of additional flags to be passed to the @command{gem}
3708 command can be specified with the @code{#:gem-flags} parameter.
3711 @defvr {Scheme Variable} waf-build-system
3712 This variable is exported by @code{(guix build-system waf)}. It
3713 implements a build procedure around the @code{waf} script. The common
3714 phases---@code{configure}, @code{build}, and @code{install}---are
3715 implemented by passing their names as arguments to the @code{waf}
3718 The @code{waf} script is executed by the Python interpreter. Which
3719 Python package is used to run the script can be specified with the
3720 @code{#:python} parameter.
3723 @defvr {Scheme Variable} haskell-build-system
3724 This variable is exported by @code{(guix build-system haskell)}. It
3725 implements the Cabal build procedure used by Haskell packages, which
3726 involves running @code{runhaskell Setup.hs configure
3727 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3728 Instead of installing the package by running @code{runhaskell Setup.hs
3729 install}, to avoid trying to register libraries in the read-only
3730 compiler store directory, the build system uses @code{runhaskell
3731 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3732 addition, the build system generates the package documentation by
3733 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3734 is passed. Optional Haddock parameters can be passed with the help of
3735 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3736 not found, the build system looks for @code{Setup.lhs} instead.
3738 Which Haskell compiler is used can be specified with the @code{#:haskell}
3739 parameter which defaults to @code{ghc}.
3742 @defvr {Scheme Variable} dub-build-system
3743 This variable is exported by @code{(guix build-system dub)}. It
3744 implements the Dub build procedure used by D packages, which
3745 involves running @code{dub build} and @code{dub run}.
3746 Installation is done by copying the files manually.
3748 Which D compiler is used can be specified with the @code{#:ldc}
3749 parameter which defaults to @code{ldc}.
3752 @defvr {Scheme Variable} emacs-build-system
3753 This variable is exported by @code{(guix build-system emacs)}. It
3754 implements an installation procedure similar to the packaging system
3755 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3757 It first creates the @code{@var{package}-autoloads.el} file, then it
3758 byte compiles all Emacs Lisp files. Differently from the Emacs
3759 packaging system, the Info documentation files are moved to the standard
3760 documentation directory and the @file{dir} file is deleted. Each
3761 package is installed in its own directory under
3762 @file{share/emacs/site-lisp/guix.d}.
3765 @defvr {Scheme Variable} font-build-system
3766 This variable is exported by @code{(guix build-system font)}. It
3767 implements an installation procedure for font packages where upstream
3768 provides pre-compiled TrueType, OpenType, etc. font files that merely
3769 need to be copied into place. It copies font files to standard
3770 locations in the output directory.
3773 Lastly, for packages that do not need anything as sophisticated, a
3774 ``trivial'' build system is provided. It is trivial in the sense that
3775 it provides basically no support: it does not pull any implicit inputs,
3776 and does not have a notion of build phases.
3778 @defvr {Scheme Variable} trivial-build-system
3779 This variable is exported by @code{(guix build-system trivial)}.
3781 This build system requires a @code{#:builder} argument. This argument
3782 must be a Scheme expression that builds the package output(s)---as
3783 with @code{build-expression->derivation} (@pxref{Derivations,
3784 @code{build-expression->derivation}}).
3794 Conceptually, the @dfn{store} is the place where derivations that have
3795 been built successfully are stored---by default, @file{/gnu/store}.
3796 Sub-directories in the store are referred to as @dfn{store items} or
3797 sometimes @dfn{store paths}. The store has an associated database that
3798 contains information such as the store paths referred to by each store
3799 path, and the list of @emph{valid} store items---results of successful
3800 builds. This database resides in @file{@var{localstatedir}/guix/db},
3801 where @var{localstatedir} is the state directory specified @i{via}
3802 @option{--localstatedir} at configure time, usually @file{/var}.
3804 The store is @emph{always} accessed by the daemon on behalf of its clients
3805 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3806 connect to the daemon over a Unix-domain socket, send requests to it,
3807 and read the result---these are remote procedure calls, or RPCs.
3810 Users must @emph{never} modify files under @file{/gnu/store} directly.
3811 This would lead to inconsistencies and break the immutability
3812 assumptions of Guix's functional model (@pxref{Introduction}).
3814 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3815 how to check the integrity of the store and attempt recovery from
3816 accidental modifications.
3819 The @code{(guix store)} module provides procedures to connect to the
3820 daemon, and to perform RPCs. These are described below. By default,
3821 @code{open-connection}, and thus all the @command{guix} commands,
3822 connect to the local daemon or to the URI specified by the
3823 @code{GUIX_DAEMON_SOCKET} environment variable.
3825 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3826 When set, the value of this variable should be a file name or a URI
3827 designating the daemon endpoint. When it is a file name, it denotes a
3828 Unix-domain socket to connect to. In addition to file names, the
3829 supported URI schemes are:
3834 These are for Unix-domain sockets.
3835 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3836 @file{/var/guix/daemon-socket/socket}.
3839 @cindex daemon, remote access
3840 @cindex remote access to the daemon
3841 @cindex daemon, cluster setup
3842 @cindex clusters, daemon setup
3843 These URIs denote connections over TCP/IP, without encryption nor
3844 authentication of the remote host. The URI must specify the host name
3845 and optionally a port number (by default port 44146 is used):
3848 guix://master.guix.example.org:1234
3851 This setup is suitable on local networks, such as clusters, where only
3852 trusted nodes may connect to the build daemon at
3853 @code{master.guix.example.org}.
3855 The @code{--listen} option of @command{guix-daemon} can be used to
3856 instruct it to listen for TCP connections (@pxref{Invoking guix-daemon,
3860 @cindex SSH access to build daemons
3861 These URIs allow you to connect to a remote daemon over
3862 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
3863 A typical URL might look like this:
3866 ssh://charlie@@guix.example.org:22
3869 As for @command{guix copy}, the usual OpenSSH client configuration files
3870 are honored (@pxref{Invoking guix copy}).
3873 Additional URI schemes may be supported in the future.
3875 @c XXX: Remove this note when the protocol incurs fewer round trips
3876 @c and when (guix derivations) no longer relies on file system access.
3878 The ability to connect to remote build daemons is considered
3879 experimental as of @value{VERSION}. Please get in touch with us to
3880 share any problems or suggestions you may have (@pxref{Contributing}).
3884 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
3885 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
3886 @var{reserve-space?} is true, instruct it to reserve a little bit of
3887 extra space on the file system so that the garbage collector can still
3888 operate should the disk become full. Return a server object.
3890 @var{file} defaults to @var{%default-socket-path}, which is the normal
3891 location given the options that were passed to @command{configure}.
3894 @deffn {Scheme Procedure} close-connection @var{server}
3895 Close the connection to @var{server}.
3898 @defvr {Scheme Variable} current-build-output-port
3899 This variable is bound to a SRFI-39 parameter, which refers to the port
3900 where build and error logs sent by the daemon should be written.
3903 Procedures that make RPCs all take a server object as their first
3906 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3907 @cindex invalid store items
3908 Return @code{#t} when @var{path} designates a valid store item and
3909 @code{#f} otherwise (an invalid item may exist on disk but still be
3910 invalid, for instance because it is the result of an aborted or failed
3913 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3914 prefixed by the store directory (@file{/gnu/store}).
3917 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3918 Add @var{text} under file @var{name} in the store, and return its store
3919 path. @var{references} is the list of store paths referred to by the
3920 resulting store path.
3923 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3924 Build @var{derivations} (a list of @code{<derivation>} objects or
3925 derivation paths), and return when the worker is done building them.
3926 Return @code{#t} on success.
3929 Note that the @code{(guix monads)} module provides a monad as well as
3930 monadic versions of the above procedures, with the goal of making it
3931 more convenient to work with code that accesses the store (@pxref{The
3935 @i{This section is currently incomplete.}
3938 @section Derivations
3941 Low-level build actions and the environment in which they are performed
3942 are represented by @dfn{derivations}. A derivation contains the
3943 following pieces of information:
3947 The outputs of the derivation---derivations produce at least one file or
3948 directory in the store, but may produce more.
3951 The inputs of the derivations, which may be other derivations or plain
3952 files in the store (patches, build scripts, etc.)
3955 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3958 The file name of a build script in the store, along with the arguments
3962 A list of environment variables to be defined.
3966 @cindex derivation path
3967 Derivations allow clients of the daemon to communicate build actions to
3968 the store. They exist in two forms: as an in-memory representation,
3969 both on the client- and daemon-side, and as files in the store whose
3970 name end in @code{.drv}---these files are referred to as @dfn{derivation
3971 paths}. Derivations paths can be passed to the @code{build-derivations}
3972 procedure to perform the build actions they prescribe (@pxref{The
3975 The @code{(guix derivations)} module provides a representation of
3976 derivations as Scheme objects, along with procedures to create and
3977 otherwise manipulate derivations. The lowest-level primitive to create
3978 a derivation is the @code{derivation} procedure:
3980 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3981 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3982 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3983 [#:system (%current-system)] [#:references-graphs #f] @
3984 [#:allowed-references #f] [#:disallowed-references #f] @
3985 [#:leaked-env-vars #f] [#:local-build? #f] @
3986 [#:substitutable? #t]
3987 Build a derivation with the given arguments, and return the resulting
3988 @code{<derivation>} object.
3990 When @var{hash} and @var{hash-algo} are given, a
3991 @dfn{fixed-output derivation} is created---i.e., one whose result is
3992 known in advance, such as a file download. If, in addition,
3993 @var{recursive?} is true, then that fixed output may be an executable
3994 file or a directory and @var{hash} must be the hash of an archive
3995 containing this output.
3997 When @var{references-graphs} is true, it must be a list of file
3998 name/store path pairs. In that case, the reference graph of each store
3999 path is exported in the build environment in the corresponding file, in
4000 a simple text format.
4002 When @var{allowed-references} is true, it must be a list of store items
4003 or outputs that the derivation's output may refer to. Likewise,
4004 @var{disallowed-references}, if true, must be a list of things the
4005 outputs may @emph{not} refer to.
4007 When @var{leaked-env-vars} is true, it must be a list of strings
4008 denoting environment variables that are allowed to ``leak'' from the
4009 daemon's environment to the build environment. This is only applicable
4010 to fixed-output derivations---i.e., when @var{hash} is true. The main
4011 use is to allow variables such as @code{http_proxy} to be passed to
4012 derivations that download files.
4014 When @var{local-build?} is true, declare that the derivation is not a
4015 good candidate for offloading and should rather be built locally
4016 (@pxref{Daemon Offload Setup}). This is the case for small derivations
4017 where the costs of data transfers would outweigh the benefits.
4019 When @var{substitutable?} is false, declare that substitutes of the
4020 derivation's output should not be used (@pxref{Substitutes}). This is
4021 useful, for instance, when building packages that capture details of the
4022 host CPU instruction set.
4026 Here's an example with a shell script as its builder, assuming
4027 @var{store} is an open connection to the daemon, and @var{bash} points
4028 to a Bash executable in the store:
4031 (use-modules (guix utils)
4035 (let ((builder ; add the Bash script to the store
4036 (add-text-to-store store "my-builder.sh"
4037 "echo hello world > $out\n" '())))
4038 (derivation store "foo"
4039 bash `("-e" ,builder)
4040 #:inputs `((,bash) (,builder))
4041 #:env-vars '(("HOME" . "/homeless"))))
4042 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
4045 As can be guessed, this primitive is cumbersome to use directly. A
4046 better approach is to write build scripts in Scheme, of course! The
4047 best course of action for that is to write the build code as a
4048 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
4049 information, @pxref{G-Expressions}.
4051 Once upon a time, @code{gexp->derivation} did not exist and constructing
4052 derivations with build code written in Scheme was achieved with
4053 @code{build-expression->derivation}, documented below. This procedure
4054 is now deprecated in favor of the much nicer @code{gexp->derivation}.
4056 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
4057 @var{name} @var{exp} @
4058 [#:system (%current-system)] [#:inputs '()] @
4059 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
4060 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4061 [#:references-graphs #f] [#:allowed-references #f] @
4062 [#:disallowed-references #f] @
4063 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4064 Return a derivation that executes Scheme expression @var{exp} as a
4065 builder for derivation @var{name}. @var{inputs} must be a list of
4066 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
4067 @code{"out"} is assumed. @var{modules} is a list of names of Guile
4068 modules from the current search path to be copied in the store,
4069 compiled, and made available in the load path during the execution of
4070 @var{exp}---e.g., @code{((guix build utils) (guix build
4071 gnu-build-system))}.
4073 @var{exp} is evaluated in an environment where @code{%outputs} is bound
4074 to a list of output/path pairs, and where @code{%build-inputs} is bound
4075 to a list of string/output-path pairs made from @var{inputs}.
4076 Optionally, @var{env-vars} is a list of string pairs specifying the name
4077 and value of environment variables visible to the builder. The builder
4078 terminates by passing the result of @var{exp} to @code{exit}; thus, when
4079 @var{exp} returns @code{#f}, the build is considered to have failed.
4081 @var{exp} is built using @var{guile-for-build} (a derivation). When
4082 @var{guile-for-build} is omitted or is @code{#f}, the value of the
4083 @code{%guile-for-build} fluid is used instead.
4085 See the @code{derivation} procedure for the meaning of
4086 @var{references-graphs}, @var{allowed-references},
4087 @var{disallowed-references}, @var{local-build?}, and
4088 @var{substitutable?}.
4092 Here's an example of a single-output derivation that creates a directory
4093 containing one file:
4096 (let ((builder '(let ((out (assoc-ref %outputs "out")))
4097 (mkdir out) ; create /gnu/store/@dots{}-goo
4098 (call-with-output-file (string-append out "/test")
4100 (display '(hello guix) p))))))
4101 (build-expression->derivation store "goo" builder))
4103 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
4107 @node The Store Monad
4108 @section The Store Monad
4112 The procedures that operate on the store described in the previous
4113 sections all take an open connection to the build daemon as their first
4114 argument. Although the underlying model is functional, they either have
4115 side effects or depend on the current state of the store.
4117 The former is inconvenient: the connection to the build daemon has to be
4118 carried around in all those functions, making it impossible to compose
4119 functions that do not take that parameter with functions that do. The
4120 latter can be problematic: since store operations have side effects
4121 and/or depend on external state, they have to be properly sequenced.
4123 @cindex monadic values
4124 @cindex monadic functions
4125 This is where the @code{(guix monads)} module comes in. This module
4126 provides a framework for working with @dfn{monads}, and a particularly
4127 useful monad for our uses, the @dfn{store monad}. Monads are a
4128 construct that allows two things: associating ``context'' with values
4129 (in our case, the context is the store), and building sequences of
4130 computations (here computations include accesses to the store). Values
4131 in a monad---values that carry this additional context---are called
4132 @dfn{monadic values}; procedures that return such values are called
4133 @dfn{monadic procedures}.
4135 Consider this ``normal'' procedure:
4138 (define (sh-symlink store)
4139 ;; Return a derivation that symlinks the 'bash' executable.
4140 (let* ((drv (package-derivation store bash))
4141 (out (derivation->output-path drv))
4142 (sh (string-append out "/bin/bash")))
4143 (build-expression->derivation store "sh"
4144 `(symlink ,sh %output))))
4147 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
4148 as a monadic function:
4151 (define (sh-symlink)
4152 ;; Same, but return a monadic value.
4153 (mlet %store-monad ((drv (package->derivation bash)))
4154 (gexp->derivation "sh"
4155 #~(symlink (string-append #$drv "/bin/bash")
4159 There are several things to note in the second version: the @code{store}
4160 parameter is now implicit and is ``threaded'' in the calls to the
4161 @code{package->derivation} and @code{gexp->derivation} monadic
4162 procedures, and the monadic value returned by @code{package->derivation}
4163 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4165 As it turns out, the call to @code{package->derivation} can even be
4166 omitted since it will take place implicitly, as we will see later
4167 (@pxref{G-Expressions}):
4170 (define (sh-symlink)
4171 (gexp->derivation "sh"
4172 #~(symlink (string-append #$bash "/bin/bash")
4177 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4178 @c for the funny quote.
4179 Calling the monadic @code{sh-symlink} has no effect. As someone once
4180 said, ``you exit a monad like you exit a building on fire: by running''.
4181 So, to exit the monad and get the desired effect, one must use
4182 @code{run-with-store}:
4185 (run-with-store (open-connection) (sh-symlink))
4186 @result{} /gnu/store/...-sh-symlink
4189 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4190 new ``meta-commands'' to make it easier to deal with monadic procedures:
4191 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4192 to ``run'' a single monadic value through the store:
4195 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4196 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4199 The latter enters a recursive REPL, where all the return values are
4200 automatically run through the store:
4203 scheme@@(guile-user)> ,enter-store-monad
4204 store-monad@@(guile-user) [1]> (package->derivation hello)
4205 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4206 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4207 $3 = "/gnu/store/@dots{}-foo"
4208 store-monad@@(guile-user) [1]> ,q
4209 scheme@@(guile-user)>
4213 Note that non-monadic values cannot be returned in the
4214 @code{store-monad} REPL.
4216 The main syntactic forms to deal with monads in general are provided by
4217 the @code{(guix monads)} module and are described below.
4219 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4220 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4224 @deffn {Scheme Syntax} return @var{val}
4225 Return a monadic value that encapsulates @var{val}.
4228 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4229 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4230 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4231 referred to as ``bind'', but that name denotes an unrelated procedure in
4232 Guile. Thus we use this somewhat cryptic symbol inherited from the
4233 Haskell language.}. There can be one @var{mproc} or several of them, as
4238 (with-monad %state-monad
4240 (lambda (x) (return (+ 1 x)))
4241 (lambda (x) (return (* 2 x)))))
4245 @result{} some-state
4249 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4251 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4253 Bind the variables @var{var} to the monadic values @var{mval} in
4254 @var{body}, which is a sequence of expressions. As with the bind
4255 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4256 value ``contained'' in @var{mval} and making @var{var} refer to that
4257 raw, non-monadic value within the scope of the @var{body}. The form
4258 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4259 @var{val}, as per @code{let}. The binding operations occur in sequence
4260 from left to right. The last expression of @var{body} must be a monadic
4261 expression, and its result will become the result of the @code{mlet} or
4262 @code{mlet*} when run in the @var{monad}.
4264 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4265 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4268 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4269 Bind @var{mexp} and the following monadic expressions in sequence,
4270 returning the result of the last expression. Every expression in the
4271 sequence must be a monadic expression.
4273 This is akin to @code{mlet}, except that the return values of the
4274 monadic expressions are ignored. In that sense, it is analogous to
4275 @code{begin}, but applied to monadic expressions.
4278 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4279 When @var{condition} is true, evaluate the sequence of monadic
4280 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4281 @var{condition} is false, return @code{*unspecified*} in the current
4282 monad. Every expression in the sequence must be a monadic expression.
4285 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4286 When @var{condition} is false, evaluate the sequence of monadic
4287 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4288 @var{condition} is true, return @code{*unspecified*} in the current
4289 monad. Every expression in the sequence must be a monadic expression.
4293 The @code{(guix monads)} module provides the @dfn{state monad}, which
4294 allows an additional value---the state---to be @emph{threaded} through
4295 monadic procedure calls.
4297 @defvr {Scheme Variable} %state-monad
4298 The state monad. Procedures in the state monad can access and change
4299 the state that is threaded.
4301 Consider the example below. The @code{square} procedure returns a value
4302 in the state monad. It returns the square of its argument, but also
4303 increments the current state value:
4307 (mlet %state-monad ((count (current-state)))
4308 (mbegin %state-monad
4309 (set-current-state (+ 1 count))
4312 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4317 When ``run'' through @var{%state-monad}, we obtain that additional state
4318 value, which is the number of @code{square} calls.
4321 @deffn {Monadic Procedure} current-state
4322 Return the current state as a monadic value.
4325 @deffn {Monadic Procedure} set-current-state @var{value}
4326 Set the current state to @var{value} and return the previous state as a
4330 @deffn {Monadic Procedure} state-push @var{value}
4331 Push @var{value} to the current state, which is assumed to be a list,
4332 and return the previous state as a monadic value.
4335 @deffn {Monadic Procedure} state-pop
4336 Pop a value from the current state and return it as a monadic value.
4337 The state is assumed to be a list.
4340 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4341 Run monadic value @var{mval} starting with @var{state} as the initial
4342 state. Return two values: the resulting value, and the resulting state.
4345 The main interface to the store monad, provided by the @code{(guix
4346 store)} module, is as follows.
4348 @defvr {Scheme Variable} %store-monad
4349 The store monad---an alias for @var{%state-monad}.
4351 Values in the store monad encapsulate accesses to the store. When its
4352 effect is needed, a value of the store monad must be ``evaluated'' by
4353 passing it to the @code{run-with-store} procedure (see below.)
4356 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4357 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4358 open store connection.
4361 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4362 Return as a monadic value the absolute file name in the store of the file
4363 containing @var{text}, a string. @var{references} is a list of store items that the
4364 resulting text file refers to; it defaults to the empty list.
4367 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4368 [#:recursive? #t] [#:select? (const #t)]
4369 Return the name of @var{file} once interned in the store. Use
4370 @var{name} as its store name, or the basename of @var{file} if
4371 @var{name} is omitted.
4373 When @var{recursive?} is true, the contents of @var{file} are added
4374 recursively; if @var{file} designates a flat file and @var{recursive?}
4375 is true, its contents are added, and its permission bits are kept.
4377 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4378 @var{stat})} for each directory entry, where @var{file} is the entry's
4379 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4380 entries for which @var{select?} does not return true.
4382 The example below adds a file to the store, under two different names:
4385 (run-with-store (open-connection)
4386 (mlet %store-monad ((a (interned-file "README"))
4387 (b (interned-file "README" "LEGU-MIN")))
4388 (return (list a b))))
4390 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4395 The @code{(guix packages)} module exports the following package-related
4398 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4399 [#:system (%current-system)] [#:target #f] @
4402 value in the absolute file name of @var{file} within the @var{output}
4403 directory of @var{package}. When @var{file} is omitted, return the name
4404 of the @var{output} directory of @var{package}. When @var{target} is
4405 true, use it as a cross-compilation target triplet.
4408 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4409 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4410 @var{target} [@var{system}]
4411 Monadic version of @code{package-derivation} and
4412 @code{package-cross-derivation} (@pxref{Defining Packages}).
4417 @section G-Expressions
4419 @cindex G-expression
4420 @cindex build code quoting
4421 So we have ``derivations'', which represent a sequence of build actions
4422 to be performed to produce an item in the store (@pxref{Derivations}).
4423 These build actions are performed when asking the daemon to actually
4424 build the derivations; they are run by the daemon in a container
4425 (@pxref{Invoking guix-daemon}).
4427 @cindex strata of code
4428 It should come as no surprise that we like to write these build actions
4429 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4430 code@footnote{The term @dfn{stratum} in this context was coined by
4431 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4432 Kiselyov, who has written insightful
4433 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4434 on this topic}, refers to this kind of code generation as
4435 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4436 to the daemon, etc.---and the ``build code''---code that actually
4437 performs build actions, such as making directories, invoking
4438 @command{make}, etc.
4440 To describe a derivation and its build actions, one typically needs to
4441 embed build code inside host code. It boils down to manipulating build
4442 code as data, and the homoiconicity of Scheme---code has a direct
4443 representation as data---comes in handy for that. But we need more than
4444 the normal @code{quasiquote} mechanism in Scheme to construct build
4447 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4448 S-expressions adapted to build expressions. G-expressions, or
4449 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4450 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4451 @code{#$}, and @code{#$@@}), which are comparable to
4452 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4453 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4454 GNU Guile Reference Manual}). However, there are major differences:
4458 Gexps are meant to be written to a file and run or manipulated by other
4462 When a high-level object such as a package or derivation is unquoted
4463 inside a gexp, the result is as if its output file name had been
4467 Gexps carry information about the packages or derivations they refer to,
4468 and these dependencies are automatically added as inputs to the build
4469 processes that use them.
4472 @cindex lowering, of high-level objects in gexps
4473 This mechanism is not limited to package and derivation
4474 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4475 derivations or files in the store can be defined,
4476 such that these objects can also be inserted
4477 into gexps. For example, a useful type of high-level objects that can be
4478 inserted in a gexp is ``file-like objects'', which make it easy to
4479 add files to the store and to refer to them in
4480 derivations and such (see @code{local-file} and @code{plain-file}
4483 To illustrate the idea, here is an example of a gexp:
4490 (symlink (string-append #$coreutils "/bin/ls")
4494 This gexp can be passed to @code{gexp->derivation}; we obtain a
4495 derivation that builds a directory containing exactly one symlink to
4496 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4499 (gexp->derivation "the-thing" build-exp)
4502 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4503 substituted to the reference to the @var{coreutils} package in the
4504 actual build code, and @var{coreutils} is automatically made an input to
4505 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4506 output)}) is replaced by a string containing the directory name of the
4507 output of the derivation.
4509 @cindex cross compilation
4510 In a cross-compilation context, it is useful to distinguish between
4511 references to the @emph{native} build of a package---that can run on the
4512 host---versus references to cross builds of a package. To that end, the
4513 @code{#+} plays the same role as @code{#$}, but is a reference to a
4514 native package build:
4517 (gexp->derivation "vi"
4520 (system* (string-append #+coreutils "/bin/ln")
4522 (string-append #$emacs "/bin/emacs")
4523 (string-append #$output "/bin/vi")))
4524 #:target "mips64el-linux-gnu")
4528 In the example above, the native build of @var{coreutils} is used, so
4529 that @command{ln} can actually run on the host; but then the
4530 cross-compiled build of @var{emacs} is referenced.
4532 @cindex imported modules, for gexps
4533 @findex with-imported-modules
4534 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4535 able to use certain Guile modules from the ``host environment'' in the
4536 gexp, so those modules should be imported in the ``build environment''.
4537 The @code{with-imported-modules} form allows you to express that:
4540 (let ((build (with-imported-modules '((guix build utils))
4542 (use-modules (guix build utils))
4543 (mkdir-p (string-append #$output "/bin"))))))
4544 (gexp->derivation "empty-dir"
4547 (display "success!\n")
4552 In this example, the @code{(guix build utils)} module is automatically
4553 pulled into the isolated build environment of our gexp, such that
4554 @code{(use-modules (guix build utils))} works as expected.
4556 @cindex module closure
4557 @findex source-module-closure
4558 Usually you want the @emph{closure} of the module to be imported---i.e.,
4559 the module itself and all the modules it depends on---rather than just
4560 the module; failing to do that, attempts to use the module will fail
4561 because of missing dependent modules. The @code{source-module-closure}
4562 procedure computes the closure of a module by looking at its source file
4563 headers, which comes in handy in this case:
4566 (use-modules (guix modules)) ;for 'source-module-closure'
4568 (with-imported-modules (source-module-closure
4569 '((guix build utils)
4571 (gexp->derivation "something-with-vms"
4573 (use-modules (guix build utils)
4578 The syntactic form to construct gexps is summarized below.
4580 @deffn {Scheme Syntax} #~@var{exp}
4581 @deffnx {Scheme Syntax} (gexp @var{exp})
4582 Return a G-expression containing @var{exp}. @var{exp} may contain one
4583 or more of the following forms:
4587 @itemx (ungexp @var{obj})
4588 Introduce a reference to @var{obj}. @var{obj} may have one of the
4589 supported types, for example a package or a
4590 derivation, in which case the @code{ungexp} form is replaced by its
4591 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4593 If @var{obj} is a list, it is traversed and references to supported
4594 objects are substituted similarly.
4596 If @var{obj} is another gexp, its contents are inserted and its
4597 dependencies are added to those of the containing gexp.
4599 If @var{obj} is another kind of object, it is inserted as is.
4601 @item #$@var{obj}:@var{output}
4602 @itemx (ungexp @var{obj} @var{output})
4603 This is like the form above, but referring explicitly to the
4604 @var{output} of @var{obj}---this is useful when @var{obj} produces
4605 multiple outputs (@pxref{Packages with Multiple Outputs}).
4608 @itemx #+@var{obj}:output
4609 @itemx (ungexp-native @var{obj})
4610 @itemx (ungexp-native @var{obj} @var{output})
4611 Same as @code{ungexp}, but produces a reference to the @emph{native}
4612 build of @var{obj} when used in a cross compilation context.
4614 @item #$output[:@var{output}]
4615 @itemx (ungexp output [@var{output}])
4616 Insert a reference to derivation output @var{output}, or to the main
4617 output when @var{output} is omitted.
4619 This only makes sense for gexps passed to @code{gexp->derivation}.
4622 @itemx (ungexp-splicing @var{lst})
4623 Like the above, but splices the contents of @var{lst} inside the
4627 @itemx (ungexp-native-splicing @var{lst})
4628 Like the above, but refers to native builds of the objects listed in
4633 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4634 of the @code{gexp?} type (see below.)
4637 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4638 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4639 in their execution environment.
4641 Each item in @var{modules} can be the name of a module, such as
4642 @code{(guix build utils)}, or it can be a module name, followed by an
4643 arrow, followed by a file-like object:
4646 `((guix build utils)
4648 ((guix config) => ,(scheme-file "config.scm"
4649 #~(define-module @dots{}))))
4653 In the example above, the first two modules are taken from the search
4654 path, and the last one is created from the given file-like object.
4656 This form has @emph{lexical} scope: it has an effect on the gexps
4657 directly defined in @var{body}@dots{}, but not on those defined, say, in
4658 procedures called from @var{body}@dots{}.
4661 @deffn {Scheme Procedure} gexp? @var{obj}
4662 Return @code{#t} if @var{obj} is a G-expression.
4665 G-expressions are meant to be written to disk, either as code building
4666 some derivation, or as plain files in the store. The monadic procedures
4667 below allow you to do that (@pxref{The Store Monad}, for more
4668 information about monads.)
4670 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4671 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4672 [#:hash #f] [#:hash-algo #f] @
4673 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4674 [#:module-path @var{%load-path}] @
4675 [#:references-graphs #f] [#:allowed-references #f] @
4676 [#:disallowed-references #f] @
4677 [#:leaked-env-vars #f] @
4678 [#:script-name (string-append @var{name} "-builder")] @
4679 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4680 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4681 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4682 stored in a file called @var{script-name}. When @var{target} is true,
4683 it is used as the cross-compilation target triplet for packages referred
4686 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4688 make @var{modules} available in the evaluation context of @var{exp};
4689 @var{modules} is a list of names of Guile modules searched in
4690 @var{module-path} to be copied in the store, compiled, and made available in
4691 the load path during the execution of @var{exp}---e.g., @code{((guix
4692 build utils) (guix build gnu-build-system))}.
4694 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4697 When @var{references-graphs} is true, it must be a list of tuples of one of the
4701 (@var{file-name} @var{package})
4702 (@var{file-name} @var{package} @var{output})
4703 (@var{file-name} @var{derivation})
4704 (@var{file-name} @var{derivation} @var{output})
4705 (@var{file-name} @var{store-item})
4708 The right-hand-side of each element of @var{references-graphs} is automatically made
4709 an input of the build process of @var{exp}. In the build environment, each
4710 @var{file-name} contains the reference graph of the corresponding item, in a simple
4713 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4714 In the latter case, the list denotes store items that the result is allowed to
4715 refer to. Any reference to another store item will lead to a build error.
4716 Similarly for @var{disallowed-references}, which can list items that must not be
4717 referenced by the outputs.
4719 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4722 @cindex file-like objects
4723 The @code{local-file}, @code{plain-file}, @code{computed-file},
4724 @code{program-file}, and @code{scheme-file} procedures below return
4725 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4726 these objects lead to a file in the store. Consider this G-expression:
4729 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4730 #$(local-file "/tmp/my-nscd.conf"))
4733 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4734 to the store. Once expanded, for instance @i{via}
4735 @code{gexp->derivation}, the G-expression refers to that copy under
4736 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4737 does not have any effect on what the G-expression does.
4738 @code{plain-file} can be used similarly; it differs in that the file
4739 content is directly passed as a string.
4741 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4742 [#:recursive? #f] [#:select? (const #t)]
4743 Return an object representing local file @var{file} to add to the store; this
4744 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4745 up relative to the source file where this form appears. @var{file} will be added to
4746 the store under @var{name}--by default the base name of @var{file}.
4748 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4749 designates a flat file and @var{recursive?} is true, its contents are added, and its
4750 permission bits are kept.
4752 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4753 @var{stat})} for each directory entry, where @var{file} is the entry's
4754 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4755 entries for which @var{select?} does not return true.
4757 This is the declarative counterpart of the @code{interned-file} monadic
4758 procedure (@pxref{The Store Monad, @code{interned-file}}).
4761 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4762 Return an object representing a text file called @var{name} with the given
4763 @var{content} (a string) to be added to the store.
4765 This is the declarative counterpart of @code{text-file}.
4768 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4769 [#:options '(#:local-build? #t)]
4770 Return an object representing the store item @var{name}, a file or
4771 directory computed by @var{gexp}. @var{options}
4772 is a list of additional arguments to pass to @code{gexp->derivation}.
4774 This is the declarative counterpart of @code{gexp->derivation}.
4777 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4778 Return an executable script @var{name} that runs @var{exp} using
4779 @var{guile}, with @var{exp}'s imported modules in its search path.
4781 The example below builds a script that simply invokes the @command{ls}
4785 (use-modules (guix gexp) (gnu packages base))
4787 (gexp->script "list-files"
4788 #~(execl #$(file-append coreutils "/bin/ls")
4792 When ``running'' it through the store (@pxref{The Store Monad,
4793 @code{run-with-store}}), we obtain a derivation that produces an
4794 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4797 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4799 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4803 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4805 Return an object representing the executable store item @var{name} that
4806 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4809 This is the declarative counterpart of @code{gexp->script}.
4812 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4813 [#:set-load-path? #t]
4814 Return a derivation that builds a file @var{name} containing @var{exp}.
4815 When @var{set-load-path?} is true, emit code in the resulting file to
4816 set @code{%load-path} and @code{%load-compiled-path} to honor
4817 @var{exp}'s imported modules.
4819 The resulting file holds references to all the dependencies of @var{exp}
4820 or a subset thereof.
4823 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4824 Return an object representing the Scheme file @var{name} that contains
4827 This is the declarative counterpart of @code{gexp->file}.
4830 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4831 Return as a monadic value a derivation that builds a text file
4832 containing all of @var{text}. @var{text} may list, in addition to
4833 strings, objects of any type that can be used in a gexp: packages,
4834 derivations, local file objects, etc. The resulting store file holds
4835 references to all these.
4837 This variant should be preferred over @code{text-file} anytime the file
4838 to create will reference items from the store. This is typically the
4839 case when building a configuration file that embeds store file names,
4843 (define (profile.sh)
4844 ;; Return the name of a shell script in the store that
4845 ;; initializes the 'PATH' environment variable.
4846 (text-file* "profile.sh"
4847 "export PATH=" coreutils "/bin:"
4848 grep "/bin:" sed "/bin\n"))
4851 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4852 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4853 preventing them from being garbage-collected during its lifetime.
4856 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4857 Return an object representing store file @var{name} containing
4858 @var{text}. @var{text} is a sequence of strings and file-like objects,
4862 (mixed-text-file "profile"
4863 "export PATH=" coreutils "/bin:" grep "/bin")
4866 This is the declarative counterpart of @code{text-file*}.
4869 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4870 Return a file-like object that expands to the concatenation of @var{obj}
4871 and @var{suffix}, where @var{obj} is a lowerable object and each
4872 @var{suffix} is a string.
4874 As an example, consider this gexp:
4877 (gexp->script "run-uname"
4878 #~(system* #$(file-append coreutils
4882 The same effect could be achieved with:
4885 (gexp->script "run-uname"
4886 #~(system* (string-append #$coreutils
4890 There is one difference though: in the @code{file-append} case, the
4891 resulting script contains the absolute file name as a string, whereas in
4892 the second case, the resulting script contains a @code{(string-append
4893 @dots{})} expression to construct the file name @emph{at run time}.
4897 Of course, in addition to gexps embedded in ``host'' code, there are
4898 also modules containing build tools. To make it clear that they are
4899 meant to be used in the build stratum, these modules are kept in the
4900 @code{(guix build @dots{})} name space.
4902 @cindex lowering, of high-level objects in gexps
4903 Internally, high-level objects are @dfn{lowered}, using their compiler,
4904 to either derivations or store items. For instance, lowering a package
4905 yields a derivation, and lowering a @code{plain-file} yields a store
4906 item. This is achieved using the @code{lower-object} monadic procedure.
4908 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4910 Return as a value in @var{%store-monad} the derivation or store item
4911 corresponding to @var{obj} for @var{system}, cross-compiling for
4912 @var{target} if @var{target} is true. @var{obj} must be an object that
4913 has an associated gexp compiler, such as a @code{<package>}.
4917 @c *********************************************************************
4921 This section describes Guix command-line utilities. Some of them are
4922 primarily targeted at developers and users who write new package
4923 definitions, while others are more generally useful. They complement
4924 the Scheme programming interface of Guix in a convenient way.
4927 * Invoking guix build:: Building packages from the command line.
4928 * Invoking guix edit:: Editing package definitions.
4929 * Invoking guix download:: Downloading a file and printing its hash.
4930 * Invoking guix hash:: Computing the cryptographic hash of a file.
4931 * Invoking guix import:: Importing package definitions.
4932 * Invoking guix refresh:: Updating package definitions.
4933 * Invoking guix lint:: Finding errors in package definitions.
4934 * Invoking guix size:: Profiling disk usage.
4935 * Invoking guix graph:: Visualizing the graph of packages.
4936 * Invoking guix environment:: Setting up development environments.
4937 * Invoking guix publish:: Sharing substitutes.
4938 * Invoking guix challenge:: Challenging substitute servers.
4939 * Invoking guix copy:: Copying to and from a remote store.
4940 * Invoking guix container:: Process isolation.
4941 * Invoking guix weather:: Assessing substitute availability.
4944 @node Invoking guix build
4945 @section Invoking @command{guix build}
4947 @cindex package building
4948 @cindex @command{guix build}
4949 The @command{guix build} command builds packages or derivations and
4950 their dependencies, and prints the resulting store paths. Note that it
4951 does not modify the user's profile---this is the job of the
4952 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4953 it is mainly useful for distribution developers.
4955 The general syntax is:
4958 guix build @var{options} @var{package-or-derivation}@dots{}
4961 As an example, the following command builds the latest versions of Emacs
4962 and of Guile, displays their build logs, and finally displays the
4963 resulting directories:
4966 guix build emacs guile
4969 Similarly, the following command builds all the available packages:
4972 guix build --quiet --keep-going \
4973 `guix package -A | cut -f1,2 --output-delimiter=@@`
4976 @var{package-or-derivation} may be either the name of a package found in
4977 the software distribution such as @code{coreutils} or
4978 @code{coreutils@@8.20}, or a derivation such as
4979 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4980 package with the corresponding name (and optionally version) is searched
4981 for among the GNU distribution modules (@pxref{Package Modules}).
4983 Alternatively, the @code{--expression} option may be used to specify a
4984 Scheme expression that evaluates to a package; this is useful when
4985 disambiguating among several same-named packages or package variants is
4988 There may be zero or more @var{options}. The available options are
4989 described in the subsections below.
4992 * Common Build Options:: Build options for most commands.
4993 * Package Transformation Options:: Creating variants of packages.
4994 * Additional Build Options:: Options specific to 'guix build'.
4995 * Debugging Build Failures:: Real life packaging experience.
4998 @node Common Build Options
4999 @subsection Common Build Options
5001 A number of options that control the build process are common to
5002 @command{guix build} and other commands that can spawn builds, such as
5003 @command{guix package} or @command{guix archive}. These are the
5008 @item --load-path=@var{directory}
5009 @itemx -L @var{directory}
5010 Add @var{directory} to the front of the package module search path
5011 (@pxref{Package Modules}).
5013 This allows users to define their own packages and make them visible to
5014 the command-line tools.
5018 Keep the build tree of failed builds. Thus, if a build fails, its build
5019 tree is kept under @file{/tmp}, in a directory whose name is shown at
5020 the end of the build log. This is useful when debugging build issues.
5021 @xref{Debugging Build Failures}, for tips and tricks on how to debug
5026 Keep going when some of the derivations fail to build; return only once
5027 all the builds have either completed or failed.
5029 The default behavior is to stop as soon as one of the specified
5030 derivations has failed.
5034 Do not build the derivations.
5037 When substituting a pre-built binary fails, fall back to building
5040 @item --substitute-urls=@var{urls}
5041 @anchor{client-substitute-urls}
5042 Consider @var{urls} the whitespace-separated list of substitute source
5043 URLs, overriding the default list of URLs of @command{guix-daemon}
5044 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
5046 This means that substitutes may be downloaded from @var{urls}, provided
5047 they are signed by a key authorized by the system administrator
5048 (@pxref{Substitutes}).
5050 When @var{urls} is the empty string, substitutes are effectively
5053 @item --no-substitutes
5054 Do not use substitutes for build products. That is, always build things
5055 locally instead of allowing downloads of pre-built binaries
5056 (@pxref{Substitutes}).
5059 Do not ``graft'' packages. In practice, this means that package updates
5060 available as grafts are not applied. @xref{Security Updates}, for more
5061 information on grafts.
5063 @item --rounds=@var{n}
5064 Build each derivation @var{n} times in a row, and raise an error if
5065 consecutive build results are not bit-for-bit identical.
5067 This is a useful way to detect non-deterministic builds processes.
5068 Non-deterministic build processes are a problem because they make it
5069 practically impossible for users to @emph{verify} whether third-party
5070 binaries are genuine. @xref{Invoking guix challenge}, for more.
5072 Note that, currently, the differing build results are not kept around,
5073 so you will have to manually investigate in case of an error---e.g., by
5074 stashing one of the build results with @code{guix archive --export}
5075 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
5078 @item --no-build-hook
5079 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
5080 (@pxref{Daemon Offload Setup}). That is, always build things locally
5081 instead of offloading builds to remote machines.
5083 @item --max-silent-time=@var{seconds}
5084 When the build or substitution process remains silent for more than
5085 @var{seconds}, terminate it and report a build failure.
5087 By default, the daemon's setting is honored (@pxref{Invoking
5088 guix-daemon, @code{--max-silent-time}}).
5090 @item --timeout=@var{seconds}
5091 Likewise, when the build or substitution process lasts for more than
5092 @var{seconds}, terminate it and report a build failure.
5094 By default, the daemon's setting is honored (@pxref{Invoking
5095 guix-daemon, @code{--timeout}}).
5097 @item --verbosity=@var{level}
5098 Use the given verbosity level. @var{level} must be an integer between 0
5099 and 5; higher means more verbose output. Setting a level of 4 or more
5100 may be helpful when debugging setup issues with the build daemon.
5102 @item --cores=@var{n}
5104 Allow the use of up to @var{n} CPU cores for the build. The special
5105 value @code{0} means to use as many CPU cores as available.
5107 @item --max-jobs=@var{n}
5109 Allow at most @var{n} build jobs in parallel. @xref{Invoking
5110 guix-daemon, @code{--max-jobs}}, for details about this option and the
5111 equivalent @command{guix-daemon} option.
5115 Behind the scenes, @command{guix build} is essentially an interface to
5116 the @code{package-derivation} procedure of the @code{(guix packages)}
5117 module, and to the @code{build-derivations} procedure of the @code{(guix
5118 derivations)} module.
5120 In addition to options explicitly passed on the command line,
5121 @command{guix build} and other @command{guix} commands that support
5122 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
5124 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
5125 Users can define this variable to a list of command line options that
5126 will automatically be used by @command{guix build} and other
5127 @command{guix} commands that can perform builds, as in the example
5131 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
5134 These options are parsed independently, and the result is appended to
5135 the parsed command-line options.
5139 @node Package Transformation Options
5140 @subsection Package Transformation Options
5142 @cindex package variants
5143 Another set of command-line options supported by @command{guix build}
5144 and also @command{guix package} are @dfn{package transformation
5145 options}. These are options that make it possible to define @dfn{package
5146 variants}---for instance, packages built from different source code.
5147 This is a convenient way to create customized packages on the fly
5148 without having to type in the definitions of package variants
5149 (@pxref{Defining Packages}).
5153 @item --with-source=@var{source}
5154 Use @var{source} as the source of the corresponding package.
5155 @var{source} must be a file name or a URL, as for @command{guix
5156 download} (@pxref{Invoking guix download}).
5158 The ``corresponding package'' is taken to be the one specified on the
5159 command line the name of which matches the base of @var{source}---e.g.,
5160 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
5161 package is @code{guile}. Likewise, the version string is inferred from
5162 @var{source}; in the previous example, it is @code{2.0.10}.
5164 This option allows users to try out versions of packages other than the
5165 one provided by the distribution. The example below downloads
5166 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5167 the @code{ed} package:
5170 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5173 As a developer, @code{--with-source} makes it easy to test release
5177 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5180 @dots{} or to build from a checkout in a pristine environment:
5183 $ git clone git://git.sv.gnu.org/guix.git
5184 $ guix build guix --with-source=./guix
5187 @item --with-input=@var{package}=@var{replacement}
5188 Replace dependency on @var{package} by a dependency on
5189 @var{replacement}. @var{package} must be a package name, and
5190 @var{replacement} must be a package specification such as @code{guile}
5191 or @code{guile@@1.8}.
5193 For instance, the following command builds Guix, but replaces its
5194 dependency on the current stable version of Guile with a dependency on
5195 the legacy version of Guile, @code{guile@@2.0}:
5198 guix build --with-input=guile=guile@@2.0 guix
5201 This is a recursive, deep replacement. So in this example, both
5202 @code{guix} and its dependency @code{guile-json} (which also depends on
5203 @code{guile}) get rebuilt against @code{guile@@2.0}.
5205 This is implemented using the @code{package-input-rewriting} Scheme
5206 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5208 @item --with-graft=@var{package}=@var{replacement}
5209 This is similar to @code{--with-input} but with an important difference:
5210 instead of rebuilding the whole dependency chain, @var{replacement} is
5211 built and then @dfn{grafted} onto the binaries that were initially
5212 referring to @var{package}. @xref{Security Updates}, for more
5213 information on grafts.
5215 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5216 and all its dependencies, replacing references to the version of GnuTLS
5217 they currently refer to:
5220 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5223 This has the advantage of being much faster than rebuilding everything.
5224 But there is a caveat: it works if and only if @var{package} and
5225 @var{replacement} are strictly compatible---for example, if they provide
5226 a library, the application binary interface (ABI) of those libraries
5227 must be compatible. If @var{replacement} is somehow incompatible with
5228 @var{package}, then the resulting package may be unusable. Use with
5233 @node Additional Build Options
5234 @subsection Additional Build Options
5236 The command-line options presented below are specific to @command{guix
5243 Build quietly, without displaying the build log. Upon completion, the
5244 build log is kept in @file{/var} (or similar) and can always be
5245 retrieved using the @option{--log-file} option.
5247 @item --file=@var{file}
5248 @itemx -f @var{file}
5250 Build the package or derivation that the code within @var{file}
5253 As an example, @var{file} might contain a package definition like this
5254 (@pxref{Defining Packages}):
5257 @verbatiminclude package-hello.scm
5260 @item --expression=@var{expr}
5261 @itemx -e @var{expr}
5262 Build the package or derivation @var{expr} evaluates to.
5264 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5265 guile-1.8)}, which unambiguously designates this specific variant of
5266 version 1.8 of Guile.
5268 Alternatively, @var{expr} may be a G-expression, in which case it is used
5269 as a build program passed to @code{gexp->derivation}
5270 (@pxref{G-Expressions}).
5272 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5273 (@pxref{The Store Monad}). The procedure must return a derivation as a
5274 monadic value, which is then passed through @code{run-with-store}.
5278 Build the source derivations of the packages, rather than the packages
5281 For instance, @code{guix build -S gcc} returns something like
5282 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5285 The returned source tarball is the result of applying any patches and
5286 code snippets specified in the package @code{origin} (@pxref{Defining
5290 Fetch and return the source of @var{package-or-derivation} and all their
5291 dependencies, recursively. This is a handy way to obtain a local copy
5292 of all the source code needed to build @var{packages}, allowing you to
5293 eventually build them even without network access. It is an extension
5294 of the @code{--source} option and can accept one of the following
5295 optional argument values:
5299 This value causes the @code{--sources} option to behave in the same way
5300 as the @code{--source} option.
5303 Build the source derivations of all packages, including any source that
5304 might be listed as @code{inputs}. This is the default value.
5307 $ guix build --sources tzdata
5308 The following derivations will be built:
5309 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5310 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5314 Build the source derivations of all packages, as well of all transitive
5315 inputs to the packages. This can be used e.g. to
5316 prefetch package source for later offline building.
5319 $ guix build --sources=transitive tzdata
5320 The following derivations will be built:
5321 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5322 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5323 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5324 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5325 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5326 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5332 @item --system=@var{system}
5333 @itemx -s @var{system}
5334 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5335 the system type of the build host.
5337 An example use of this is on Linux-based systems, which can emulate
5338 different personalities. For instance, passing
5339 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5340 to build packages in a complete 32-bit environment.
5342 @item --target=@var{triplet}
5343 @cindex cross-compilation
5344 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5345 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5346 configuration triplets,, autoconf, Autoconf}).
5348 @anchor{build-check}
5350 @cindex determinism, checking
5351 @cindex reproducibility, checking
5352 Rebuild @var{package-or-derivation}, which are already available in the
5353 store, and raise an error if the build results are not bit-for-bit
5356 This mechanism allows you to check whether previously installed
5357 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5358 of a package is deterministic. @xref{Invoking guix challenge}, for more
5359 background information and tools.
5361 When used in conjunction with @option{--keep-failed}, the differing
5362 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5363 This makes it easy to look for differences between the two results.
5366 @cindex repairing store items
5367 @cindex corruption, recovering from
5368 Attempt to repair the specified store items, if they are corrupt, by
5369 re-downloading or rebuilding them.
5371 This operation is not atomic and thus restricted to @code{root}.
5375 Return the derivation paths, not the output paths, of the given
5378 @item --root=@var{file}
5379 @itemx -r @var{file}
5380 Make @var{file} a symlink to the result, and register it as a garbage
5384 Return the build log file names or URLs for the given
5385 @var{package-or-derivation}, or raise an error if build logs are
5388 This works regardless of how packages or derivations are specified. For
5389 instance, the following invocations are equivalent:
5392 guix build --log-file `guix build -d guile`
5393 guix build --log-file `guix build guile`
5394 guix build --log-file guile
5395 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5398 If a log is unavailable locally, and unless @code{--no-substitutes} is
5399 passed, the command looks for a corresponding log on one of the
5400 substitute servers (as specified with @code{--substitute-urls}.)
5402 So for instance, imagine you want to see the build log of GDB on MIPS,
5403 but you are actually on an @code{x86_64} machine:
5406 $ guix build --log-file gdb -s mips64el-linux
5407 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5410 You can freely access a huge library of build logs!
5413 @node Debugging Build Failures
5414 @subsection Debugging Build Failures
5416 @cindex build failures, debugging
5417 When defining a new package (@pxref{Defining Packages}), you will
5418 probably find yourself spending some time debugging and tweaking the
5419 build until it succeeds. To do that, you need to operate the build
5420 commands yourself in an environment as close as possible to the one the
5423 To that end, the first thing to do is to use the @option{--keep-failed}
5424 or @option{-K} option of @command{guix build}, which will keep the
5425 failed build tree in @file{/tmp} or whatever directory you specified as
5426 @code{TMPDIR} (@pxref{Invoking guix build, @code{--keep-failed}}).
5428 From there on, you can @command{cd} to the failed build tree and source
5429 the @file{environment-variables} file, which contains all the
5430 environment variable definitions that were in place when the build
5431 failed. So let's say you're debugging a build failure in package
5432 @code{foo}; a typical session would look like this:
5436 @dots{} @i{build fails}
5437 $ cd /tmp/guix-build-foo.drv-0
5438 $ source ./environment-variables
5442 Now, you can invoke commands as if you were the daemon (almost) and
5443 troubleshoot your build process.
5445 Sometimes it happens that, for example, a package's tests pass when you
5446 run them manually but they fail when the daemon runs them. This can
5447 happen because the daemon runs builds in containers where, unlike in our
5448 environment above, network access is missing, @file{/bin/sh} does not
5449 exist, etc. (@pxref{Build Environment Setup}).
5451 In such cases, you may need to run inspect the build process from within
5452 a container similar to the one the build daemon creates:
5457 $ cd /tmp/guix-build-foo.drv-0
5458 $ guix environment --no-grafts -C foo --ad-hoc strace gdb
5459 [env]# source ./environment-variables
5463 Here, @command{guix environment -C} creates a container and spawns a new
5464 shell in it (@pxref{Invoking guix environment}). The @command{--ad-hoc
5465 strace gdb} part adds the @command{strace} and @command{gdb} commands to
5466 the container, which would may find handy while debugging. The
5467 @option{--no-grafts} option makes sure we get the exact same
5468 environment, with ungrafted packages (@pxref{Security Updates}, for more
5471 To get closer to a container like that used by the build daemon, we can
5472 remove @file{/bin/sh}:
5478 (Don't worry, this is harmless: this is all happening in the throw-away
5479 container created by @command{guix environment}.)
5481 The @command{strace} command is probably not in the search path, but we
5485 [env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check
5488 In this way, not only you will have reproduced the environment variables
5489 the daemon uses, you will also be running the build process in a container
5490 similar to the one the daemon uses.
5493 @node Invoking guix edit
5494 @section Invoking @command{guix edit}
5496 @cindex @command{guix edit}
5497 @cindex package definition, editing
5498 So many packages, so many source files! The @command{guix edit} command
5499 facilitates the life of users and packagers by pointing their editor at
5500 the source file containing the definition of the specified packages.
5504 guix edit gcc@@4.9 vim
5508 launches the program specified in the @code{VISUAL} or in the
5509 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5512 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5513 have created your own packages on @code{GUIX_PACKAGE_PATH}
5514 (@pxref{Defining Packages}), you will be able to edit the package
5515 recipes. Otherwise, you will be able to examine the read-only recipes
5516 for packages currently in the store.
5519 @node Invoking guix download
5520 @section Invoking @command{guix download}
5522 @cindex @command{guix download}
5523 @cindex downloading package sources
5524 When writing a package definition, developers typically need to download
5525 a source tarball, compute its SHA256 hash, and write that
5526 hash in the package definition (@pxref{Defining Packages}). The
5527 @command{guix download} tool helps with this task: it downloads a file
5528 from the given URI, adds it to the store, and prints both its file name
5529 in the store and its SHA256 hash.
5531 The fact that the downloaded file is added to the store saves bandwidth:
5532 when the developer eventually tries to build the newly defined package
5533 with @command{guix build}, the source tarball will not have to be
5534 downloaded again because it is already in the store. It is also a
5535 convenient way to temporarily stash files, which may be deleted
5536 eventually (@pxref{Invoking guix gc}).
5538 The @command{guix download} command supports the same URIs as used in
5539 package definitions. In particular, it supports @code{mirror://} URIs.
5540 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5541 Guile bindings for GnuTLS are available in the user's environment; when
5542 they are not available, an error is raised. @xref{Guile Preparations,
5543 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5544 GnuTLS-Guile}, for more information.
5546 @command{guix download} verifies HTTPS server certificates by loading
5547 the certificates of X.509 authorities from the directory pointed to by
5548 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5549 Certificates}), unless @option{--no-check-certificate} is used.
5551 The following options are available:
5554 @item --format=@var{fmt}
5556 Write the hash in the format specified by @var{fmt}. For more
5557 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5559 @item --no-check-certificate
5560 Do not validate the X.509 certificates of HTTPS servers.
5562 When using this option, you have @emph{absolutely no guarantee} that you
5563 are communicating with the authentic server responsible for the given
5564 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5566 @item --output=@var{file}
5567 @itemx -o @var{file}
5568 Save the downloaded file to @var{file} instead of adding it to the
5572 @node Invoking guix hash
5573 @section Invoking @command{guix hash}
5575 @cindex @command{guix hash}
5576 The @command{guix hash} command computes the SHA256 hash of a file.
5577 It is primarily a convenience tool for anyone contributing to the
5578 distribution: it computes the cryptographic hash of a file, which can be
5579 used in the definition of a package (@pxref{Defining Packages}).
5581 The general syntax is:
5584 guix hash @var{option} @var{file}
5587 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5588 hash of data read from standard input. @command{guix hash} has the
5593 @item --format=@var{fmt}
5595 Write the hash in the format specified by @var{fmt}.
5597 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5598 (@code{hex} and @code{hexadecimal} can be used as well).
5600 If the @option{--format} option is not specified, @command{guix hash}
5601 will output the hash in @code{nix-base32}. This representation is used
5602 in the definitions of packages.
5606 Compute the hash on @var{file} recursively.
5608 In this case, the hash is computed on an archive containing @var{file},
5609 including its children if it is a directory. Some of the metadata of
5610 @var{file} is part of the archive; for instance, when @var{file} is a
5611 regular file, the hash is different depending on whether @var{file} is
5612 executable or not. Metadata such as time stamps has no impact on the
5613 hash (@pxref{Invoking guix archive}).
5614 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5619 When combined with @option{--recursive}, exclude version control system
5620 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5623 As an example, here is how you would compute the hash of a Git checkout,
5624 which is useful when using the @code{git-fetch} method (@pxref{origin
5628 $ git clone http://example.org/foo.git
5634 @node Invoking guix import
5635 @section Invoking @command{guix import}
5637 @cindex importing packages
5638 @cindex package import
5639 @cindex package conversion
5640 @cindex Invoking @command{guix import}
5641 The @command{guix import} command is useful for people who would like to
5642 add a package to the distribution with as little work as
5643 possible---a legitimate demand. The command knows of a few
5644 repositories from which it can ``import'' package metadata. The result
5645 is a package definition, or a template thereof, in the format we know
5646 (@pxref{Defining Packages}).
5648 The general syntax is:
5651 guix import @var{importer} @var{options}@dots{}
5654 @var{importer} specifies the source from which to import package
5655 metadata, and @var{options} specifies a package identifier and other
5656 options specific to @var{importer}. Currently, the available
5661 Import metadata for the given GNU package. This provides a template
5662 for the latest version of that GNU package, including the hash of its
5663 source tarball, and its canonical synopsis and description.
5665 Additional information such as the package dependencies and its
5666 license needs to be figured out manually.
5668 For example, the following command returns a package definition for
5672 guix import gnu hello
5675 Specific command-line options are:
5678 @item --key-download=@var{policy}
5679 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5680 keys when verifying the package signature. @xref{Invoking guix
5681 refresh, @code{--key-download}}.
5686 Import metadata from the @uref{https://pypi.python.org/, Python Package
5687 Index}@footnote{This functionality requires Guile-JSON to be installed.
5688 @xref{Requirements}.}. Information is taken from the JSON-formatted
5689 description available at @code{pypi.python.org} and usually includes all
5690 the relevant information, including package dependencies. For maximum
5691 efficiency, it is recommended to install the @command{unzip} utility, so
5692 that the importer can unzip Python wheels and gather data from them.
5694 The command below imports metadata for the @code{itsdangerous} Python
5698 guix import pypi itsdangerous
5703 Import metadata from @uref{https://rubygems.org/,
5704 RubyGems}@footnote{This functionality requires Guile-JSON to be
5705 installed. @xref{Requirements}.}. Information is taken from the
5706 JSON-formatted description available at @code{rubygems.org} and includes
5707 most relevant information, including runtime dependencies. There are
5708 some caveats, however. The metadata doesn't distinguish between
5709 synopses and descriptions, so the same string is used for both fields.
5710 Additionally, the details of non-Ruby dependencies required to build
5711 native extensions is unavailable and left as an exercise to the
5714 The command below imports metadata for the @code{rails} Ruby package:
5717 guix import gem rails
5722 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5723 functionality requires Guile-JSON to be installed.
5724 @xref{Requirements}.}.
5725 Information is taken from the JSON-formatted metadata provided through
5726 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5727 relevant information, such as module dependencies. License information
5728 should be checked closely. If Perl is available in the store, then the
5729 @code{corelist} utility will be used to filter core modules out of the
5730 list of dependencies.
5732 The command command below imports metadata for the @code{Acme::Boolean}
5736 guix import cpan Acme::Boolean
5741 @cindex Bioconductor
5742 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5743 central repository for the @uref{http://r-project.org, GNU@tie{}R
5744 statistical and graphical environment}.
5746 Information is extracted from the @code{DESCRIPTION} file of the package.
5748 The command command below imports metadata for the @code{Cairo}
5752 guix import cran Cairo
5755 When @code{--recursive} is added, the importer will traverse the
5756 dependency graph of the given upstream package recursively and generate
5757 package expressions for all those packages that are not yet in Guix.
5759 When @code{--archive=bioconductor} is added, metadata is imported from
5760 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5761 packages for for the analysis and comprehension of high-throughput
5762 genomic data in bioinformatics.
5764 Information is extracted from the @code{DESCRIPTION} file of a package
5765 published on the web interface of the Bioconductor SVN repository.
5767 The command below imports metadata for the @code{GenomicRanges}
5771 guix import cran --archive=bioconductor GenomicRanges
5777 Import metadata from @uref{http://www.ctan.org/, CTAN}, the
5778 comprehensive TeX archive network for TeX packages that are part of the
5779 @uref{https://www.tug.org/texlive/, TeX Live distribution}.
5781 Information about the package is obtained through the XML API provided
5782 by CTAN, while the source code is downloaded from the SVN repository of
5783 the Tex Live project. This is done because the CTAN does not keep
5786 The command command below imports metadata for the @code{fontspec}
5790 guix import texlive fontspec
5793 When @code{--archive=DIRECTORY} is added, the source code is downloaded
5794 not from the @file{latex} sub-directory of the @file{texmf-dist/source}
5795 tree in the TeX Live SVN repository, but from the specified sibling
5796 directory under the same root.
5798 The command below imports metadata for the @code{ifxetex} package from
5799 CTAN while fetching the sources from the directory
5800 @file{texmf/source/generic}:
5803 guix import texlive --archive=generic ifxetex
5807 Import metadata from a local copy of the source of the
5808 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5809 relies on the @command{nix-instantiate} command of
5810 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5811 typically written in a mixture of Nix-language and Bash code. This
5812 command only imports the high-level package structure that is written in
5813 the Nix language. It normally includes all the basic fields of a
5816 When importing a GNU package, the synopsis and descriptions are replaced
5817 by their canonical upstream variant.
5819 Usually, you will first need to do:
5822 export NIX_REMOTE=daemon
5826 so that @command{nix-instantiate} does not try to open the Nix database.
5828 As an example, the command below imports the package definition of
5829 LibreOffice (more precisely, it imports the definition of the package
5830 bound to the @code{libreoffice} top-level attribute):
5833 guix import nix ~/path/to/nixpkgs libreoffice
5838 Import metadata from the Haskell community's central package archive
5839 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5840 Cabal files and includes all the relevant information, including package
5843 Specific command-line options are:
5848 Read a Cabal file from standard input.
5849 @item --no-test-dependencies
5851 Do not include dependencies required only by the test suites.
5852 @item --cabal-environment=@var{alist}
5853 @itemx -e @var{alist}
5854 @var{alist} is a Scheme alist defining the environment in which the
5855 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5856 @code{arch}, @code{impl} and a string representing the name of a flag.
5857 The value associated with a flag has to be either the symbol
5858 @code{true} or @code{false}. The value associated with other keys
5859 has to conform to the Cabal file format definition. The default value
5860 associated with the keys @code{os}, @code{arch} and @code{impl} is
5861 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5864 The command below imports metadata for the latest version of the
5865 @code{HTTP} Haskell package without including test dependencies and
5866 specifying the value of the flag @samp{network-uri} as @code{false}:
5869 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5872 A specific package version may optionally be specified by following the
5873 package name by an at-sign and a version number as in the following example:
5876 guix import hackage mtl@@2.1.3.1
5881 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5882 It takes a package name, looks up the package version included in a
5883 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5884 release and uses the @code{hackage} importer to retrieve its metadata.
5885 Note that it is up to you to select an LTS release compatible with the
5886 GHC compiler used by Guix.
5888 Specific command-line options are:
5891 @item --no-test-dependencies
5893 Do not include dependencies required only by the test suites.
5894 @item --lts-version=@var{version}
5895 @itemx -r @var{version}
5896 @var{version} is the desired LTS release version. If omitted the latest
5900 The command below imports metadata for the @code{HTTP} Haskell package
5901 included in the LTS Stackage release version 7.18:
5904 guix import stackage --lts-version=7.18 HTTP
5909 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5910 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5912 Specific command-line options are:
5915 @item --archive=@var{repo}
5916 @itemx -a @var{repo}
5917 @var{repo} identifies the archive repository from which to retrieve the
5918 information. Currently the supported repositories and their identifiers
5922 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5923 identifier. This is the default.
5925 Packages from @code{elpa.gnu.org} are signed with one of the keys
5926 contained in the GnuPG keyring at
5927 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5928 @code{emacs} package (@pxref{Package Installation, ELPA package
5929 signatures,, emacs, The GNU Emacs Manual}).
5932 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5933 @code{melpa-stable} identifier.
5936 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5943 Import metadata from the crates.io Rust package repository
5944 @uref{https://crates.io, crates.io}.
5947 The structure of the @command{guix import} code is modular. It would be
5948 useful to have more importers for other package formats, and your help
5949 is welcome here (@pxref{Contributing}).
5951 @node Invoking guix refresh
5952 @section Invoking @command{guix refresh}
5954 @cindex @command {guix refresh}
5955 The primary audience of the @command{guix refresh} command is developers
5956 of the GNU software distribution. By default, it reports any packages
5957 provided by the distribution that are outdated compared to the latest
5958 upstream version, like this:
5962 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5963 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5966 Alternately, one can specify packages to consider, in which case a
5967 warning is emitted for packages that lack an updater:
5970 $ guix refresh coreutils guile guile-ssh
5971 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5972 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5975 @command{guix refresh} browses the upstream repository of each package and determines
5976 the highest version number of the releases therein. The command
5977 knows how to update specific types of packages: GNU packages, ELPA
5978 packages, etc.---see the documentation for @option{--type} below. There
5979 are many packages, though, for which it lacks a method to determine
5980 whether a new upstream release is available. However, the mechanism is
5981 extensible, so feel free to get in touch with us to add a new method!
5983 When passed @code{--update}, it modifies distribution source files to
5984 update the version numbers and source tarball hashes of those package
5985 recipes (@pxref{Defining Packages}). This is achieved by downloading
5986 each package's latest source tarball and its associated OpenPGP
5987 signature, authenticating the downloaded tarball against its signature
5988 using @command{gpg}, and finally computing its hash. When the public
5989 key used to sign the tarball is missing from the user's keyring, an
5990 attempt is made to automatically retrieve it from a public key server;
5991 when this is successful, the key is added to the user's keyring; otherwise,
5992 @command{guix refresh} reports an error.
5994 The following options are supported:
5998 @item --expression=@var{expr}
5999 @itemx -e @var{expr}
6000 Consider the package @var{expr} evaluates to.
6002 This is useful to precisely refer to a package, as in this example:
6005 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
6008 This command lists the dependents of the ``final'' libc (essentially all
6013 Update distribution source files (package recipes) in place. This is
6014 usually run from a checkout of the Guix source tree (@pxref{Running
6015 Guix Before It Is Installed}):
6018 $ ./pre-inst-env guix refresh -s non-core -u
6021 @xref{Defining Packages}, for more information on package definitions.
6023 @item --select=[@var{subset}]
6024 @itemx -s @var{subset}
6025 Select all the packages in @var{subset}, one of @code{core} or
6028 The @code{core} subset refers to all the packages at the core of the
6029 distribution---i.e., packages that are used to build ``everything
6030 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
6031 changing one of these packages in the distribution entails a rebuild of
6032 all the others. Thus, such updates are an inconvenience to users in
6033 terms of build time or bandwidth used to achieve the upgrade.
6035 The @code{non-core} subset refers to the remaining packages. It is
6036 typically useful in cases where an update of the core packages would be
6039 @item --manifest=@var{file}
6040 @itemx -m @var{file}
6041 Select all the packages from the manifest in @var{file}. This is useful to
6042 check if any packages of the user manifest can be updated.
6044 @item --type=@var{updater}
6045 @itemx -t @var{updater}
6046 Select only packages handled by @var{updater} (may be a comma-separated
6047 list of updaters). Currently, @var{updater} may be one of:
6051 the updater for GNU packages;
6053 the updater for GNOME packages;
6055 the updater for KDE packages;
6057 the updater for X.org packages;
6059 the updater for packages hosted on kernel.org;
6061 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
6063 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
6065 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
6067 the updater for @uref{http://www.cpan.org/, CPAN} packages;
6069 the updater for @uref{https://pypi.python.org, PyPI} packages.
6071 the updater for @uref{https://rubygems.org, RubyGems} packages.
6073 the updater for @uref{https://github.com, GitHub} packages.
6075 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
6077 the updater for @uref{https://www.stackage.org, Stackage} packages.
6079 the updater for @uref{https://crates.io, Crates} packages.
6082 For instance, the following command only checks for updates of Emacs
6083 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
6086 $ guix refresh --type=elpa,cran
6087 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
6088 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
6093 In addition, @command{guix refresh} can be passed one or more package
6094 names, as in this example:
6097 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
6101 The command above specifically updates the @code{emacs} and
6102 @code{idutils} packages. The @code{--select} option would have no
6103 effect in this case.
6105 When considering whether to upgrade a package, it is sometimes
6106 convenient to know which packages would be affected by the upgrade and
6107 should be checked for compatibility. For this the following option may
6108 be used when passing @command{guix refresh} one or more package names:
6112 @item --list-updaters
6114 List available updaters and exit (see @option{--type} above.)
6116 For each updater, display the fraction of packages it covers; at the
6117 end, display the fraction of packages covered by all these updaters.
6119 @item --list-dependent
6121 List top-level dependent packages that would need to be rebuilt as a
6122 result of upgrading one or more packages.
6124 @xref{Invoking guix graph, the @code{reverse-package} type of
6125 @command{guix graph}}, for information on how to visualize the list of
6126 dependents of a package.
6130 Be aware that the @code{--list-dependent} option only
6131 @emph{approximates} the rebuilds that would be required as a result of
6132 an upgrade. More rebuilds might be required under some circumstances.
6135 $ guix refresh --list-dependent flex
6136 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
6137 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
6140 The command above lists a set of packages that could be built to check
6141 for compatibility with an upgraded @code{flex} package.
6143 The following options can be used to customize GnuPG operation:
6147 @item --gpg=@var{command}
6148 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
6149 for in @code{$PATH}.
6151 @item --key-download=@var{policy}
6152 Handle missing OpenPGP keys according to @var{policy}, which may be one
6157 Always download missing OpenPGP keys from the key server, and add them
6158 to the user's GnuPG keyring.
6161 Never try to download missing OpenPGP keys. Instead just bail out.
6164 When a package signed with an unknown OpenPGP key is encountered, ask
6165 the user whether to download it or not. This is the default behavior.
6168 @item --key-server=@var{host}
6169 Use @var{host} as the OpenPGP key server when importing a public key.
6173 The @code{github} updater uses the
6174 @uref{https://developer.github.com/v3/, GitHub API} to query for new
6175 releases. When used repeatedly e.g. when refreshing all packages,
6176 GitHub will eventually refuse to answer any further API requests. By
6177 default 60 API requests per hour are allowed, and a full refresh on all
6178 GitHub packages in Guix requires more than this. Authentication with
6179 GitHub through the use of an API token alleviates these limits. To use
6180 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
6181 token procured from @uref{https://github.com/settings/tokens} or
6185 @node Invoking guix lint
6186 @section Invoking @command{guix lint}
6188 @cindex @command{guix lint}
6189 @cindex package, checking for errors
6190 The @command{guix lint} command is meant to help package developers avoid
6191 common errors and use a consistent style. It runs a number of checks on
6192 a given set of packages in order to find common mistakes in their
6193 definitions. Available @dfn{checkers} include (see
6194 @code{--list-checkers} for a complete list):
6199 Validate certain typographical and stylistic rules about package
6200 descriptions and synopses.
6202 @item inputs-should-be-native
6203 Identify inputs that should most likely be native inputs.
6208 @itemx source-file-name
6209 Probe @code{home-page} and @code{source} URLs and report those that are
6210 invalid. Suggest a @code{mirror://} URL when applicable. Check that
6211 the source file name is meaningful, e.g. is not
6212 just a version number or ``git-checkout'', without a declared
6213 @code{file-name} (@pxref{origin Reference}).
6216 @cindex security vulnerabilities
6217 @cindex CVE, Common Vulnerabilities and Exposures
6218 Report known vulnerabilities found in the Common Vulnerabilities and
6219 Exposures (CVE) databases of the current and past year
6220 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
6223 To view information about a particular vulnerability, visit pages such as:
6227 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
6229 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
6233 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
6234 @code{CVE-2015-7554}.
6236 Package developers can specify in package recipes the
6237 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
6238 name and version of the package when they differ from the name that Guix
6239 uses, as in this example:
6245 ;; CPE calls this package "grub2".
6246 (properties '((cpe-name . "grub2"))))
6250 Warn about obvious source code formatting issues: trailing white space,
6251 use of tabulations, etc.
6254 The general syntax is:
6257 guix lint @var{options} @var{package}@dots{}
6260 If no package is given on the command line, then all packages are checked.
6261 The @var{options} may be zero or more of the following:
6264 @item --list-checkers
6266 List and describe all the available checkers that will be run on packages
6271 Only enable the checkers specified in a comma-separated list using the
6272 names returned by @code{--list-checkers}.
6276 @node Invoking guix size
6277 @section Invoking @command{guix size}
6280 @cindex package size
6282 @cindex @command{guix size}
6283 The @command{guix size} command helps package developers profile the
6284 disk usage of packages. It is easy to overlook the impact of an
6285 additional dependency added to a package, or the impact of using a
6286 single output for a package that could easily be split (@pxref{Packages
6287 with Multiple Outputs}). Such are the typical issues that
6288 @command{guix size} can highlight.
6290 The command can be passed a package specification such as @code{gcc@@4.8}
6291 or @code{guile:debug}, or a file name in the store. Consider this
6295 $ guix size coreutils
6296 store item total self
6297 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6298 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6299 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6300 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6301 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6302 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6306 The store items listed here constitute the @dfn{transitive closure} of
6307 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6308 would be returned by:
6311 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6314 Here the output shows three columns next to store items. The first column,
6315 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6316 the store item---that is, its own size plus the size of all its
6317 dependencies. The next column, labeled ``self'', shows the size of the
6318 item itself. The last column shows the ratio of the size of the item
6319 itself to the space occupied by all the items listed here.
6321 In this example, we see that the closure of Coreutils weighs in at
6322 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6323 large fraction of the closure is not a problem @i{per se} because it is
6324 always available on the system anyway.)
6326 When the package passed to @command{guix size} is available in the
6327 store, @command{guix size} queries the daemon to determine its
6328 dependencies, and measures its size in the store, similar to @command{du
6329 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6332 When the given package is @emph{not} in the store, @command{guix size}
6333 reports information based on the available substitutes
6334 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6335 store items that are not even on disk, only available remotely.
6337 You can also specify several package names:
6340 $ guix size coreutils grep sed bash
6341 store item total self
6342 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6343 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6344 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6345 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6351 In this example we see that the combination of the four packages takes
6352 102.3@tie{}MiB in total, which is much less than the sum of each closure
6353 since they have a lot of dependencies in common.
6355 The available options are:
6359 @item --substitute-urls=@var{urls}
6360 Use substitute information from @var{urls}.
6361 @xref{client-substitute-urls, the same option for @code{guix build}}.
6363 @item --sort=@var{key}
6364 Sort lines according to @var{key}, one of the following options:
6368 the total size of the item's closure (the default);
6370 the size of each item.
6373 @item --map-file=@var{file}
6374 Write a graphical map of disk usage in PNG format to @var{file}.
6376 For the example above, the map looks like this:
6378 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6379 produced by @command{guix size}}
6381 This option requires that
6382 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6383 installed and visible in Guile's module search path. When that is not
6384 the case, @command{guix size} fails as it tries to load it.
6386 @item --system=@var{system}
6387 @itemx -s @var{system}
6388 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6392 @node Invoking guix graph
6393 @section Invoking @command{guix graph}
6396 @cindex @command{guix graph}
6397 @cindex package dependencies
6398 Packages and their dependencies form a @dfn{graph}, specifically a
6399 directed acyclic graph (DAG). It can quickly become difficult to have a
6400 mental model of the package DAG, so the @command{guix graph} command
6401 provides a visual representation of the DAG. By default,
6402 @command{guix graph} emits a DAG representation in the input format of
6403 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6404 directly to the @command{dot} command of Graphviz. It can also emit an
6405 HTML page with embedded JavaScript code to display a ``chord diagram''
6406 in a Web browser, using the @uref{https://d3js.org/, d3.js} library, or
6407 emit Cypher queries to construct a graph in a graph database supporting
6408 the @uref{http://www.opencypher.org/, openCypher} query language.
6409 The general syntax is:
6412 guix graph @var{options} @var{package}@dots{}
6415 For example, the following command generates a PDF file representing the
6416 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6420 guix graph coreutils | dot -Tpdf > dag.pdf
6423 The output looks like this:
6425 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6427 Nice little graph, no?
6429 But there is more than one graph! The one above is concise: it is the
6430 graph of package objects, omitting implicit inputs such as GCC, libc,
6431 grep, etc. It is often useful to have such a concise graph, but
6432 sometimes one may want to see more details. @command{guix graph} supports
6433 several types of graphs, allowing you to choose the level of detail:
6437 This is the default type used in the example above. It shows the DAG of
6438 package objects, excluding implicit dependencies. It is concise, but
6439 filters out many details.
6441 @item reverse-package
6442 This shows the @emph{reverse} DAG of packages. For example:
6445 guix graph --type=reverse-package ocaml
6448 ... yields the graph of packages that depend on OCaml.
6450 Note that for core packages this can yield huge graphs. If all you want
6451 is to know the number of packages that depend on a given package, use
6452 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6453 @option{--list-dependent}}).
6456 This is the package DAG, @emph{including} implicit inputs.
6458 For instance, the following command:
6461 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6464 ... yields this bigger graph:
6466 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6468 At the bottom of the graph, we see all the implicit inputs of
6469 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6471 Now, note that the dependencies of these implicit inputs---that is, the
6472 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6473 here, for conciseness.
6476 Similar to @code{bag-emerged}, but this time including all the bootstrap
6479 @item bag-with-origins
6480 Similar to @code{bag}, but also showing origins and their dependencies.
6483 This is the most detailed representation: It shows the DAG of
6484 derivations (@pxref{Derivations}) and plain store items. Compared to
6485 the above representation, many additional nodes are visible, including
6486 build scripts, patches, Guile modules, etc.
6488 For this type of graph, it is also possible to pass a @file{.drv} file
6489 name instead of a package name, as in:
6492 guix graph -t derivation `guix system build -d my-config.scm`
6496 All the types above correspond to @emph{build-time dependencies}. The
6497 following graph type represents the @emph{run-time dependencies}:
6501 This is the graph of @dfn{references} of a package output, as returned
6502 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6504 If the given package output is not available in the store, @command{guix
6505 graph} attempts to obtain dependency information from substitutes.
6507 Here you can also pass a store file name instead of a package name. For
6508 example, the command below produces the reference graph of your profile
6509 (which can be big!):
6512 guix graph -t references `readlink -f ~/.guix-profile`
6516 This is the graph of the @dfn{referrers} of a store item, as returned by
6517 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6519 This relies exclusively on local information from your store. For
6520 instance, let us suppose that the current Inkscape is available in 10
6521 profiles on your machine; @command{guix graph -t referrers inkscape}
6522 will show a graph rooted at Inkscape and with those 10 profiles linked
6525 It can help determine what is preventing a store item from being garbage
6530 The available options are the following:
6533 @item --type=@var{type}
6534 @itemx -t @var{type}
6535 Produce a graph output of @var{type}, where @var{type} must be one of
6536 the values listed above.
6539 List the supported graph types.
6541 @item --backend=@var{backend}
6542 @itemx -b @var{backend}
6543 Produce a graph using the selected @var{backend}.
6545 @item --list-backends
6546 List the supported graph backends.
6548 Currently, the available backends are Graphviz and d3.js.
6550 @item --expression=@var{expr}
6551 @itemx -e @var{expr}
6552 Consider the package @var{expr} evaluates to.
6554 This is useful to precisely refer to a package, as in this example:
6557 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6562 @node Invoking guix environment
6563 @section Invoking @command{guix environment}
6565 @cindex reproducible build environments
6566 @cindex development environments
6567 @cindex @command{guix environment}
6568 @cindex environment, package build environment
6569 The purpose of @command{guix environment} is to assist hackers in
6570 creating reproducible development environments without polluting their
6571 package profile. The @command{guix environment} tool takes one or more
6572 packages, builds all of their inputs, and creates a shell
6573 environment to use them.
6575 The general syntax is:
6578 guix environment @var{options} @var{package}@dots{}
6581 The following example spawns a new shell set up for the development of
6585 guix environment guile
6588 If the needed dependencies are not built yet, @command{guix environment}
6589 automatically builds them. The environment of the new shell is an augmented
6590 version of the environment that @command{guix environment} was run in.
6591 It contains the necessary search paths for building the given package
6592 added to the existing environment variables. To create a ``pure''
6593 environment, in which the original environment variables have been unset,
6594 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6595 environment variables such as @code{PATH} in their @file{~/.bashrc}
6596 file. As a consequence, when @code{guix environment} launches it, Bash
6597 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6598 environment variables. It is an error to define such environment
6599 variables in @file{.bashrc}; instead, they should be defined in
6600 @file{.bash_profile}, which is sourced only by log-in shells.
6601 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6602 details on Bash start-up files.}.
6604 @vindex GUIX_ENVIRONMENT
6605 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6606 variable in the shell it spawns; its value is the file name of the
6607 profile of this environment. This allows users to, say, define a
6608 specific prompt for development environments in their @file{.bashrc}
6609 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6612 if [ -n "$GUIX_ENVIRONMENT" ]
6614 export PS1="\u@@\h \w [dev]\$ "
6619 ... or to browse the profile:
6622 $ ls "$GUIX_ENVIRONMENT/bin"
6625 Additionally, more than one package may be specified, in which case the
6626 union of the inputs for the given packages are used. For example, the
6627 command below spawns a shell where all of the dependencies of both Guile
6628 and Emacs are available:
6631 guix environment guile emacs
6634 Sometimes an interactive shell session is not desired. An arbitrary
6635 command may be invoked by placing the @code{--} token to separate the
6636 command from the rest of the arguments:
6639 guix environment guile -- make -j4
6642 In other situations, it is more convenient to specify the list of
6643 packages needed in the environment. For example, the following command
6644 runs @command{python} from an environment containing Python@tie{}2.7 and
6648 guix environment --ad-hoc python2-numpy python-2.7 -- python
6651 Furthermore, one might want the dependencies of a package and also some
6652 additional packages that are not build-time or runtime dependencies, but
6653 are useful when developing nonetheless. Because of this, the
6654 @code{--ad-hoc} flag is positional. Packages appearing before
6655 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6656 added to the environment. Packages appearing after are interpreted as
6657 packages that will be added to the environment directly. For example,
6658 the following command creates a Guix development environment that
6659 additionally includes Git and strace:
6662 guix environment guix --ad-hoc git strace
6665 Sometimes it is desirable to isolate the environment as much as
6666 possible, for maximal purity and reproducibility. In particular, when
6667 using Guix on a host distro that is not GuixSD, it is desirable to
6668 prevent access to @file{/usr/bin} and other system-wide resources from
6669 the development environment. For example, the following command spawns
6670 a Guile REPL in a ``container'' where only the store and the current
6671 working directory are mounted:
6674 guix environment --ad-hoc --container guile -- guile
6678 The @code{--container} option requires Linux-libre 3.19 or newer.
6681 The available options are summarized below.
6684 @item --root=@var{file}
6685 @itemx -r @var{file}
6686 @cindex persistent environment
6687 @cindex garbage collector root, for environments
6688 Make @var{file} a symlink to the profile for this environment, and
6689 register it as a garbage collector root.
6691 This is useful if you want to protect your environment from garbage
6692 collection, to make it ``persistent''.
6694 When this option is omitted, the environment is protected from garbage
6695 collection only for the duration of the @command{guix environment}
6696 session. This means that next time you recreate the same environment,
6697 you could have to rebuild or re-download packages.
6699 @item --expression=@var{expr}
6700 @itemx -e @var{expr}
6701 Create an environment for the package or list of packages that
6702 @var{expr} evaluates to.
6704 For example, running:
6707 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6710 starts a shell with the environment for this specific variant of the
6716 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6719 starts a shell with all the GuixSD base packages available.
6721 The above commands only use the default output of the given packages.
6722 To select other outputs, two element tuples can be specified:
6725 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6728 @item --load=@var{file}
6729 @itemx -l @var{file}
6730 Create an environment for the package or list of packages that the code
6731 within @var{file} evaluates to.
6733 As an example, @var{file} might contain a definition like this
6734 (@pxref{Defining Packages}):
6737 @verbatiminclude environment-gdb.scm
6741 Include all specified packages in the resulting environment, as if an
6742 @i{ad hoc} package were defined with them as inputs. This option is
6743 useful for quickly creating an environment without having to write a
6744 package expression to contain the desired inputs.
6746 For instance, the command:
6749 guix environment --ad-hoc guile guile-sdl -- guile
6752 runs @command{guile} in an environment where Guile and Guile-SDL are
6755 Note that this example implicitly asks for the default output of
6756 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6757 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6758 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6760 This option may be composed with the default behavior of @command{guix
6761 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6762 as packages whose dependencies will be added to the environment, the
6763 default behavior. Packages appearing after are interpreted as packages
6764 that will be added to the environment directly.
6767 Unset existing environment variables when building the new environment.
6768 This has the effect of creating an environment in which search paths
6769 only contain package inputs.
6771 @item --search-paths
6772 Display the environment variable definitions that make up the
6775 @item --system=@var{system}
6776 @itemx -s @var{system}
6777 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6782 Run @var{command} within an isolated container. The current working
6783 directory outside the container is mapped inside the container.
6784 Additionally, a dummy home directory is created that matches the current
6785 user's home directory, and @file{/etc/passwd} is configured accordingly.
6786 The spawned process runs as the current user outside the container, but
6787 has root privileges in the context of the container.
6791 For containers, share the network namespace with the host system.
6792 Containers created without this flag only have access to the loopback
6795 @item --expose=@var{source}[=@var{target}]
6796 For containers, expose the file system @var{source} from the host system
6797 as the read-only file system @var{target} within the container. If
6798 @var{target} is not specified, @var{source} is used as the target mount
6799 point in the container.
6801 The example below spawns a Guile REPL in a container in which the user's
6802 home directory is accessible read-only via the @file{/exchange}
6806 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6809 @item --share=@var{source}[=@var{target}]
6810 For containers, share the file system @var{source} from the host system
6811 as the writable file system @var{target} within the container. If
6812 @var{target} is not specified, @var{source} is used as the target mount
6813 point in the container.
6815 The example below spawns a Guile REPL in a container in which the user's
6816 home directory is accessible for both reading and writing via the
6817 @file{/exchange} directory:
6820 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6824 @command{guix environment}
6825 also supports all of the common build options that @command{guix
6826 build} supports (@pxref{Common Build Options}).
6829 @node Invoking guix publish
6830 @section Invoking @command{guix publish}
6832 @cindex @command{guix publish}
6833 The purpose of @command{guix publish} is to enable users to easily share
6834 their store with others, who can then use it as a substitute server
6835 (@pxref{Substitutes}).
6837 When @command{guix publish} runs, it spawns an HTTP server which allows
6838 anyone with network access to obtain substitutes from it. This means
6839 that any machine running Guix can also act as if it were a build farm,
6840 since the HTTP interface is compatible with Hydra, the software behind
6841 the @code{hydra.gnu.org} build farm.
6843 For security, each substitute is signed, allowing recipients to check
6844 their authenticity and integrity (@pxref{Substitutes}). Because
6845 @command{guix publish} uses the signing key of the system, which is only
6846 readable by the system administrator, it must be started as root; the
6847 @code{--user} option makes it drop root privileges early on.
6849 The signing key pair must be generated before @command{guix publish} is
6850 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6853 The general syntax is:
6856 guix publish @var{options}@dots{}
6859 Running @command{guix publish} without any additional arguments will
6860 spawn an HTTP server on port 8080:
6866 Once a publishing server has been authorized (@pxref{Invoking guix
6867 archive}), the daemon may download substitutes from it:
6870 guix-daemon --substitute-urls=http://example.org:8080
6873 By default, @command{guix publish} compresses archives on the fly as it
6874 serves them. This ``on-the-fly'' mode is convenient in that it requires
6875 no setup and is immediately available. However, when serving lots of
6876 clients, we recommend using the @option{--cache} option, which enables
6877 caching of the archives before they are sent to clients---see below for
6878 details. The @command{guix weather} command provides a handy way to
6879 check what a server provides (@pxref{Invoking guix weather}).
6881 As a bonus, @command{guix publish} also serves as a content-addressed
6882 mirror for source files referenced in @code{origin} records
6883 (@pxref{origin Reference}). For instance, assuming @command{guix
6884 publish} is running on @code{example.org}, the following URL returns the
6885 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6886 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6889 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6892 Obviously, these URLs only work for files that are in the store; in
6893 other cases, they return 404 (``Not Found'').
6895 The following options are available:
6898 @item --port=@var{port}
6899 @itemx -p @var{port}
6900 Listen for HTTP requests on @var{port}.
6902 @item --listen=@var{host}
6903 Listen on the network interface for @var{host}. The default is to
6904 accept connections from any interface.
6906 @item --user=@var{user}
6907 @itemx -u @var{user}
6908 Change privileges to @var{user} as soon as possible---i.e., once the
6909 server socket is open and the signing key has been read.
6911 @item --compression[=@var{level}]
6912 @itemx -C [@var{level}]
6913 Compress data using the given @var{level}. When @var{level} is zero,
6914 disable compression. The range 1 to 9 corresponds to different gzip
6915 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6918 Unless @option{--cache} is used, compression occurs on the fly and
6919 the compressed streams are not
6920 cached. Thus, to reduce load on the machine that runs @command{guix
6921 publish}, it may be a good idea to choose a low compression level, to
6922 run @command{guix publish} behind a caching proxy, or to use
6923 @option{--cache}. Using @option{--cache} has the advantage that it
6924 allows @command{guix publish} to add @code{Content-Length} HTTP header
6927 @item --cache=@var{directory}
6928 @itemx -c @var{directory}
6929 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6930 and only serve archives that are in cache.
6932 When this option is omitted, archives and meta-data are created
6933 on-the-fly. This can reduce the available bandwidth, especially when
6934 compression is enabled, since this may become CPU-bound. Another
6935 drawback of the default mode is that the length of archives is not known
6936 in advance, so @command{guix publish} does not add a
6937 @code{Content-Length} HTTP header to its responses, which in turn
6938 prevents clients from knowing the amount of data being downloaded.
6940 Conversely, when @option{--cache} is used, the first request for a store
6941 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6942 background process to @dfn{bake} the archive---computing its
6943 @code{.narinfo} and compressing the archive, if needed. Once the
6944 archive is cached in @var{directory}, subsequent requests succeed and
6945 are served directly from the cache, which guarantees that clients get
6946 the best possible bandwidth.
6948 The ``baking'' process is performed by worker threads. By default, one
6949 thread per CPU core is created, but this can be customized. See
6950 @option{--workers} below.
6952 When @option{--ttl} is used, cached entries are automatically deleted
6953 when they have expired.
6955 @item --workers=@var{N}
6956 When @option{--cache} is used, request the allocation of @var{N} worker
6957 threads to ``bake'' archives.
6959 @item --ttl=@var{ttl}
6960 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6961 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6962 days, @code{1m} means 1 month, and so on.
6964 This allows the user's Guix to keep substitute information in cache for
6965 @var{ttl}. However, note that @code{guix publish} does not itself
6966 guarantee that the store items it provides will indeed remain available
6967 for as long as @var{ttl}.
6969 Additionally, when @option{--cache} is used, cached entries that have
6970 not been accessed for @var{ttl} and that no longer have a corresponding
6971 item in the store, may be deleted.
6973 @item --nar-path=@var{path}
6974 Use @var{path} as the prefix for the URLs of ``nar'' files
6975 (@pxref{Invoking guix archive, normalized archives}).
6977 By default, nars are served at a URL such as
6978 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6979 change the @code{/nar} part to @var{path}.
6981 @item --public-key=@var{file}
6982 @itemx --private-key=@var{file}
6983 Use the specific @var{file}s as the public/private key pair used to sign
6984 the store items being published.
6986 The files must correspond to the same key pair (the private key is used
6987 for signing and the public key is merely advertised in the signature
6988 metadata). They must contain keys in the canonical s-expression format
6989 as produced by @command{guix archive --generate-key} (@pxref{Invoking
6990 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
6991 @file{/etc/guix/signing-key.sec} are used.
6993 @item --repl[=@var{port}]
6994 @itemx -r [@var{port}]
6995 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
6996 Reference Manual}) on @var{port} (37146 by default). This is used
6997 primarily for debugging a running @command{guix publish} server.
7000 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
7001 instantiate a @code{guix-publish-service-type} service in the @code{services} field
7002 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
7003 @code{guix-publish-service-type}}).
7005 If you are instead running Guix on a ``foreign distro'', follow these
7010 If your host distro uses the systemd init system:
7013 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
7014 /etc/systemd/system/
7015 # systemctl start guix-publish && systemctl enable guix-publish
7019 If your host distro uses the Upstart init system:
7022 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
7023 # start guix-publish
7027 Otherwise, proceed similarly with your distro's init system.
7030 @node Invoking guix challenge
7031 @section Invoking @command{guix challenge}
7033 @cindex reproducible builds
7034 @cindex verifiable builds
7035 @cindex @command{guix challenge}
7037 Do the binaries provided by this server really correspond to the source
7038 code it claims to build? Is a package build process deterministic?
7039 These are the questions the @command{guix challenge} command attempts to
7042 The former is obviously an important question: Before using a substitute
7043 server (@pxref{Substitutes}), one had better @emph{verify} that it
7044 provides the right binaries, and thus @emph{challenge} it. The latter
7045 is what enables the former: If package builds are deterministic, then
7046 independent builds of the package should yield the exact same result,
7047 bit for bit; if a server provides a binary different from the one
7048 obtained locally, it may be either corrupt or malicious.
7050 We know that the hash that shows up in @file{/gnu/store} file names is
7051 the hash of all the inputs of the process that built the file or
7052 directory---compilers, libraries, build scripts,
7053 etc. (@pxref{Introduction}). Assuming deterministic build processes,
7054 one store file name should map to exactly one build output.
7055 @command{guix challenge} checks whether there is, indeed, a single
7056 mapping by comparing the build outputs of several independent builds of
7057 any given store item.
7059 The command output looks like this:
7062 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
7063 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
7064 updating list of substitutes from 'https://guix.example.org'... 100.0%
7065 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
7066 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
7067 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
7068 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
7069 /gnu/store/@dots{}-git-2.5.0 contents differ:
7070 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
7071 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
7072 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
7073 /gnu/store/@dots{}-pius-2.1.1 contents differ:
7074 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
7075 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
7076 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
7080 In this example, @command{guix challenge} first scans the store to
7081 determine the set of locally-built derivations---as opposed to store
7082 items that were downloaded from a substitute server---and then queries
7083 all the substitute servers. It then reports those store items for which
7084 the servers obtained a result different from the local build.
7086 @cindex non-determinism, in package builds
7087 As an example, @code{guix.example.org} always gets a different answer.
7088 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
7089 case of Git. This might indicate that the build process of Git is
7090 non-deterministic, meaning that its output varies as a function of
7091 various things that Guix does not fully control, in spite of building
7092 packages in isolated environments (@pxref{Features}). Most common
7093 sources of non-determinism include the addition of timestamps in build
7094 results, the inclusion of random numbers, and directory listings sorted
7095 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
7098 To find out what is wrong with this Git binary, we can do something along
7099 these lines (@pxref{Invoking guix archive}):
7102 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
7103 | guix archive -x /tmp/git
7104 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
7107 This command shows the difference between the files resulting from the
7108 local build, and the files resulting from the build on
7109 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
7110 diffutils, Comparing and Merging Files}). The @command{diff} command
7111 works great for text files. When binary files differ, a better option
7112 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
7113 visualize differences for all kinds of files.
7115 Once you have done that work, you can tell whether the differences are due
7116 to a non-deterministic build process or to a malicious server. We try
7117 hard to remove sources of non-determinism in packages to make it easier
7118 to verify substitutes, but of course, this is a process that
7119 involves not just Guix, but a large part of the free software community.
7120 In the meantime, @command{guix challenge} is one tool to help address
7123 If you are writing packages for Guix, you are encouraged to check
7124 whether @code{hydra.gnu.org} and other substitute servers obtain the
7125 same build result as you did with:
7128 $ guix challenge @var{package}
7132 where @var{package} is a package specification such as
7133 @code{guile@@2.0} or @code{glibc:debug}.
7135 The general syntax is:
7138 guix challenge @var{options} [@var{packages}@dots{}]
7141 When a difference is found between the hash of a locally-built item and
7142 that of a server-provided substitute, or among substitutes provided by
7143 different servers, the command displays it as in the example above and
7144 its exit code is 2 (other non-zero exit codes denote other kinds of
7147 The one option that matters is:
7151 @item --substitute-urls=@var{urls}
7152 Consider @var{urls} the whitespace-separated list of substitute source
7157 Show details about matches (identical contents) in addition to
7158 information about mismatches.
7162 @node Invoking guix copy
7163 @section Invoking @command{guix copy}
7165 @cindex copy, of store items, over SSH
7166 @cindex SSH, copy of store items
7167 @cindex sharing store items across machines
7168 @cindex transferring store items across machines
7169 The @command{guix copy} command copies items from the store of one
7170 machine to that of another machine over a secure shell (SSH)
7171 connection@footnote{This command is available only when Guile-SSH was
7172 found. @xref{Requirements}, for details.}. For example, the following
7173 command copies the @code{coreutils} package, the user's profile, and all
7174 their dependencies over to @var{host}, logged in as @var{user}:
7177 guix copy --to=@var{user}@@@var{host} \
7178 coreutils `readlink -f ~/.guix-profile`
7181 If some of the items to be copied are already present on @var{host},
7182 they are not actually sent.
7184 The command below retrieves @code{libreoffice} and @code{gimp} from
7185 @var{host}, assuming they are available there:
7188 guix copy --from=@var{host} libreoffice gimp
7191 The SSH connection is established using the Guile-SSH client, which is
7192 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
7193 @file{~/.ssh/config}, and uses the SSH agent for authentication.
7195 The key used to sign items that are sent must be accepted by the remote
7196 machine. Likewise, the key used by the remote machine to sign items you
7197 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
7198 own daemon. @xref{Invoking guix archive}, for more information about
7199 store item authentication.
7201 The general syntax is:
7204 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
7207 You must always specify one of the following options:
7210 @item --to=@var{spec}
7211 @itemx --from=@var{spec}
7212 Specify the host to send to or receive from. @var{spec} must be an SSH
7213 spec such as @code{example.org}, @code{charlie@@example.org}, or
7214 @code{charlie@@example.org:2222}.
7217 The @var{items} can be either package names, such as @code{gimp}, or
7218 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
7220 When specifying the name of a package to send, it is first built if
7221 needed, unless @option{--dry-run} was specified. Common build options
7222 are supported (@pxref{Common Build Options}).
7225 @node Invoking guix container
7226 @section Invoking @command{guix container}
7228 @cindex @command{guix container}
7230 As of version @value{VERSION}, this tool is experimental. The interface
7231 is subject to radical change in the future.
7234 The purpose of @command{guix container} is to manipulate processes
7235 running within an isolated environment, commonly known as a
7236 ``container'', typically created by the @command{guix environment}
7237 (@pxref{Invoking guix environment}) and @command{guix system container}
7238 (@pxref{Invoking guix system}) commands.
7240 The general syntax is:
7243 guix container @var{action} @var{options}@dots{}
7246 @var{action} specifies the operation to perform with a container, and
7247 @var{options} specifies the context-specific arguments for the action.
7249 The following actions are available:
7253 Execute a command within the context of a running container.
7258 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
7261 @var{pid} specifies the process ID of the running container.
7262 @var{program} specifies an executable file name within the root file
7263 system of the container. @var{arguments} are the additional options that
7264 will be passed to @var{program}.
7266 The following command launches an interactive login shell inside a
7267 GuixSD container, started by @command{guix system container}, and whose
7271 guix container exec 9001 /run/current-system/profile/bin/bash --login
7274 Note that the @var{pid} cannot be the parent process of a container. It
7275 must be PID 1 of the container or one of its child processes.
7279 @node Invoking guix weather
7280 @section Invoking @command{guix weather}
7282 Occasionally you're grumpy because substitutes are lacking and you end
7283 up building packages by yourself (@pxref{Substitutes}). The
7284 @command{guix weather} command reports on substitute availability on the
7285 specified servers so you can have an idea of whether you'll be grumpy
7286 today. It can sometimes be useful info as a user, but it is primarily
7287 useful to people running @command{guix publish} (@pxref{Invoking guix
7290 @cindex statistics, for substitutes
7291 @cindex availability of substitutes
7292 @cindex substitute availability
7293 @cindex weather, substitute availability
7294 Here's a sample run:
7297 $ guix weather --substitute-urls=https://guix.example.org
7298 computing 5,872 package derivations for x86_64-linux...
7299 looking for 6,128 store items on https://guix.example.org..
7300 updating list of substitutes from 'https://guix.example.org'... 100.0%
7301 https://guix.example.org
7302 43.4% substitutes available (2,658 out of 6,128)
7303 7,032.5 MiB of nars (compressed)
7304 19,824.2 MiB on disk (uncompressed)
7305 0.030 seconds per request (182.9 seconds in total)
7306 33.5 requests per second
7309 As you can see, it reports the fraction of all the packages for which
7310 substitutes are available on the server---regardless of whether
7311 substitutes are enabled, and regardless of whether this server's signing
7312 key is authorized. It also reports the size of the compressed archives
7313 (``nars'') provided by the server, the size the corresponding store
7314 items occupy in the store (assuming deduplication is turned off), and
7315 the server's throughput.
7317 To achieve that, @command{guix weather} queries over HTTP(S) meta-data
7318 (@dfn{narinfos}) for all the relevant store items. Like @command{guix
7319 challenge}, it ignores signatures on those substitutes, which is
7320 innocuous since the command only gathers statistics and cannot install
7323 Among other things, it is possible to query specific system types and
7324 specific package sets. The available options are listed below.
7327 @item --substitute-urls=@var{urls}
7328 @var{urls} is the space-separated list of substitute server URLs to
7329 query. When this option is omitted, the default set of substitute
7332 @item --system=@var{system}
7333 @itemx -s @var{system}
7334 Query substitutes for @var{system}---e.g., @code{aarch64-linux}. This
7335 option can be repeated, in which case @command{guix weather} will query
7336 substitutes for several system types.
7338 @item --manifest=@var{file}
7339 Instead of querying substitutes for all the packages, only ask for those
7340 specified in @var{file}. @var{file} must contain a @dfn{manifest}, as
7341 with the @code{-m} option of @command{guix package} (@pxref{Invoking
7346 @c *********************************************************************
7347 @node GNU Distribution
7348 @chapter GNU Distribution
7350 @cindex Guix System Distribution
7352 Guix comes with a distribution of the GNU system consisting entirely of
7353 free software@footnote{The term ``free'' here refers to the
7354 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
7355 users of that software}.}. The
7356 distribution can be installed on its own (@pxref{System Installation}),
7357 but it is also possible to install Guix as a package manager on top of
7358 an installed GNU/Linux system (@pxref{Installation}). To distinguish
7359 between the two, we refer to the standalone distribution as the Guix
7360 System Distribution, or GuixSD.
7362 The distribution provides core GNU packages such as GNU libc, GCC, and
7363 Binutils, as well as many GNU and non-GNU applications. The complete
7364 list of available packages can be browsed
7365 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7366 running @command{guix package} (@pxref{Invoking guix package}):
7369 guix package --list-available
7372 Our goal is to provide a practical 100% free software distribution of
7373 Linux-based and other variants of GNU, with a focus on the promotion and
7374 tight integration of GNU components, and an emphasis on programs and
7375 tools that help users exert that freedom.
7377 Packages are currently available on the following platforms:
7382 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7385 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7388 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7389 using the EABI hard-float application binary interface (ABI),
7390 and Linux-Libre kernel.
7393 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7394 currently in an experimental stage, with limited support.
7395 @xref{Contributing}, for how to help!
7397 @item mips64el-linux
7398 little-endian 64-bit MIPS processors, specifically the Loongson series,
7399 n32 ABI, and Linux-Libre kernel.
7403 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7406 For information on porting to other architectures or kernels,
7410 * System Installation:: Installing the whole operating system.
7411 * System Configuration:: Configuring the operating system.
7412 * Documentation:: Browsing software user manuals.
7413 * Installing Debugging Files:: Feeding the debugger.
7414 * Security Updates:: Deploying security fixes quickly.
7415 * Package Modules:: Packages from the programmer's viewpoint.
7416 * Packaging Guidelines:: Growing the distribution.
7417 * Bootstrapping:: GNU/Linux built from scratch.
7418 * Porting:: Targeting another platform or kernel.
7421 Building this distribution is a cooperative effort, and you are invited
7422 to join! @xref{Contributing}, for information about how you can help.
7424 @node System Installation
7425 @section System Installation
7427 @cindex installing GuixSD
7428 @cindex Guix System Distribution
7429 This section explains how to install the Guix System Distribution (GuixSD)
7430 on a machine. The Guix package manager can
7431 also be installed on top of a running GNU/Linux system,
7432 @pxref{Installation}.
7436 @c This paragraph is for people reading this from tty2 of the
7437 @c installation image.
7438 You are reading this documentation with an Info reader. For details on
7439 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7440 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7441 Info}. Hit @kbd{l} afterwards to come back here.
7443 Alternately, run @command{info info} in another tty to keep the manual
7449 * Limitations:: What you can expect.
7450 * Hardware Considerations:: Supported hardware.
7451 * USB Stick Installation:: Preparing the installation medium.
7452 * Preparing for Installation:: Networking, partitioning, etc.
7453 * Proceeding with the Installation:: The real thing.
7454 * Installing GuixSD in a VM:: GuixSD playground.
7455 * Building the Installation Image:: How this comes to be.
7459 @subsection Limitations
7461 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7462 not production-ready. It may contain bugs and lack important
7463 features. Thus, if you are looking for a stable production system that
7464 respects your freedom as a computer user, a good solution at this point
7465 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7466 the more established GNU/Linux distributions}. We hope you can soon switch
7467 to the GuixSD without fear, of course. In the meantime, you can
7468 also keep using your distribution and try out the package manager on top
7469 of it (@pxref{Installation}).
7471 Before you proceed with the installation, be aware of the following
7472 noteworthy limitations applicable to version @value{VERSION}:
7476 The installation process does not include a graphical user interface and
7477 requires familiarity with GNU/Linux (see the following subsections to
7478 get a feel of what that means.)
7481 Support for the Logical Volume Manager (LVM) is missing.
7484 More and more system services are provided (@pxref{Services}), but some
7488 More than 5,300 packages are available, but you may
7489 occasionally find that a useful package is missing.
7492 GNOME, Xfce, LXDE, and Enlightenment are available (@pxref{Desktop Services}),
7493 as well as a number of X11 window managers. However, some graphical
7494 applications may be missing, as well as KDE.
7497 You have been warned! But more than a disclaimer, this is an invitation
7498 to report issues (and success stories!), and to join us in improving it.
7499 @xref{Contributing}, for more info.
7502 @node Hardware Considerations
7503 @subsection Hardware Considerations
7505 @cindex hardware support on GuixSD
7506 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7507 builds around the kernel Linux-libre, which means that only hardware for
7508 which free software drivers and firmware exist is supported. Nowadays,
7509 a wide range of off-the-shelf hardware is supported on
7510 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7511 Ethernet controllers. Unfortunately, there are still areas where
7512 hardware vendors deny users control over their own computing, and such
7513 hardware is not supported on GuixSD.
7515 @cindex WiFi, hardware support
7516 One of the main areas where free drivers or firmware are lacking is WiFi
7517 devices. WiFi devices known to work include those using Atheros chips
7518 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7519 driver, and those using Broadcom/AirForce chips (BCM43xx with
7520 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7521 Linux-libre driver. Free firmware exists for both and is available
7522 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7523 (@pxref{operating-system Reference, @code{firmware}}).
7525 @cindex RYF, Respects Your Freedom
7526 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7527 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7528 certification program for hardware products that respect your freedom
7529 and your privacy and ensure that you have control over your device. We
7530 encourage you to check the list of RYF-certified devices.
7532 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7533 web site. It contains a catalog of hardware devices with information
7534 about their support in GNU/Linux.
7537 @node USB Stick Installation
7538 @subsection USB Stick Installation
7540 An installation image for USB sticks can be downloaded from
7541 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
7542 where @var{system} is one of:
7546 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7549 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7552 @c start duplication of authentication part from ``Binary Installation''
7553 Make sure to download the associated @file{.sig} file and to verify the
7554 authenticity of the image against it, along these lines:
7557 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7558 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7561 If that command fails because you do not have the required public key,
7562 then run this command to import it:
7565 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7569 and rerun the @code{gpg --verify} command.
7572 This image contains a single partition with the tools necessary for an
7573 installation. It is meant to be copied @emph{as is} to a large-enough
7576 To copy the image to a USB stick, follow these steps:
7580 Decompress the image using the @command{xz} command:
7583 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
7587 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7588 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7589 copy the image with:
7592 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
7596 Access to @file{/dev/sdX} usually requires root privileges.
7599 Once this is done, you should be able to reboot the system and boot from
7600 the USB stick. The latter usually requires you to get in the BIOS or
7601 UEFI boot menu, where you can choose to boot from the USB stick.
7603 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7604 GuixSD in a virtual machine (VM).
7606 @node Preparing for Installation
7607 @subsection Preparing for Installation
7609 Once you have successfully booted the image on the USB stick, you should
7610 end up with a root prompt. Several console TTYs are configured and can
7611 be used to run commands as root. TTY2 shows this documentation,
7612 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7613 Stand-alone GNU Info}). The installation system runs the GPM mouse
7614 daemon, which allows you to select text with the left mouse button and
7615 to paste it with the middle button.
7618 Installation requires access to the Internet so that any missing
7619 dependencies of your system configuration can be downloaded. See the
7620 ``Networking'' section below.
7623 The installation system includes many common tools needed for this task.
7624 But it is also a full-blown GuixSD system, which means that you can
7625 install additional packages, should you need it, using @command{guix
7626 package} (@pxref{Invoking guix package}).
7628 @subsubsection Keyboard Layout
7630 @cindex keyboard layout
7631 The installation image uses the US qwerty keyboard layout. If you want
7632 to change it, you can use the @command{loadkeys} command. For example,
7633 the following command selects the Dvorak keyboard layout:
7639 See the files under @file{/run/current-system/profile/share/keymaps} for
7640 a list of available keyboard layouts. Run @command{man loadkeys} for
7643 @subsubsection Networking
7645 Run the following command see what your network interfaces are called:
7652 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7658 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7659 Wired interfaces have a name starting with @samp{e}; for example, the
7660 interface corresponding to the first on-board Ethernet controller is
7661 called @samp{eno1}. Wireless interfaces have a name starting with
7662 @samp{w}, like @samp{w1p2s0}.
7665 @item Wired connection
7666 To configure a wired network run the following command, substituting
7667 @var{interface} with the name of the wired interface you want to use.
7670 ifconfig @var{interface} up
7673 @item Wireless connection
7676 To configure wireless networking, you can create a configuration file
7677 for the @command{wpa_supplicant} configuration tool (its location is not
7678 important) using one of the available text editors such as
7682 zile wpa_supplicant.conf
7685 As an example, the following stanza can go to this file and will work
7686 for many wireless networks, provided you give the actual SSID and
7687 passphrase for the network you are connecting to:
7691 ssid="@var{my-ssid}"
7693 psk="the network's secret passphrase"
7697 Start the wireless service and run it in the background with the
7698 following command (substitute @var{interface} with the name of the
7699 network interface you want to use):
7702 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7705 Run @command{man wpa_supplicant} for more information.
7709 At this point, you need to acquire an IP address. On a network where IP
7710 addresses are automatically assigned @i{via} DHCP, you can run:
7713 dhclient -v @var{interface}
7716 Try to ping a server to see if networking is up and running:
7722 Setting up network access is almost always a requirement because the
7723 image does not contain all the software and tools that may be needed.
7725 @cindex installing over SSH
7726 If you want to, you can continue the installation remotely by starting
7730 herd start ssh-daemon
7733 Make sure to either set a password with @command{passwd}, or configure
7734 OpenSSH public key authentication before logging in.
7736 @subsubsection Disk Partitioning
7738 Unless this has already been done, the next step is to partition, and
7739 then format the target partition(s).
7741 The installation image includes several partitioning tools, including
7742 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7743 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7744 the partition layout you want:
7750 If your disk uses the GUID Partition Table (GPT) format and you plan to
7751 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7752 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7755 @cindex EFI, installation
7756 @cindex UEFI, installation
7757 @cindex ESP, EFI system partition
7758 If you instead wish to use EFI-based GRUB, a FAT32 @dfn{EFI System Partition}
7759 (ESP) is required. This partition should be mounted at @file{/boot/efi} and
7760 must have the @code{esp} flag set. E.g., for @command{parted}:
7763 parted /dev/sda set 1 esp on
7766 Once you are done partitioning the target hard disk drive, you have to
7767 create a file system on the relevant partition(s)@footnote{Currently
7768 GuixSD only supports ext4 and btrfs file systems. In particular, code
7769 that reads partition UUIDs and labels only works for these file system
7772 Preferably, assign partitions a label so that you can easily and
7773 reliably refer to them in @code{file-system} declarations (@pxref{File
7774 Systems}). This is typically done using the @code{-L} option of
7775 @command{mkfs.ext4} and related commands. So, assuming the target root
7776 partition lives at @file{/dev/sda1}, a file system with the label
7777 @code{my-root} can be created with:
7780 mkfs.ext4 -L my-root /dev/sda1
7783 @cindex encrypted disk
7784 If you are instead planning to encrypt the root partition, you can use
7785 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7786 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7787 @code{man cryptsetup}} for more information.) Assuming you want to
7788 store the root partition on @file{/dev/sda1}, the command sequence would
7789 be along these lines:
7792 cryptsetup luksFormat /dev/sda1
7793 cryptsetup open --type luks /dev/sda1 my-partition
7794 mkfs.ext4 -L my-root /dev/mapper/my-partition
7797 Once that is done, mount the target root partition under @file{/mnt}
7798 with a command like (again, assuming @code{my-root} is the label of the
7802 mount LABEL=my-root /mnt
7805 Also mount any other partitions you would like to use on the target
7806 system relative to this path. If you have @file{/boot} on a separate
7807 partition for example, mount it at @file{/mnt/boot} now so it is found
7808 by @code{guix system init} afterwards.
7810 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7811 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7812 sure to initialize them with @command{mkswap}. Assuming you have one
7813 swap partition on @file{/dev/sda2}, you would run:
7820 Alternatively, you may use a swap file. For example, assuming that in
7821 the new system you want to use the file @file{/swapfile} as a swap file,
7822 you would run@footnote{This example will work for many types of file
7823 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7824 btrfs), the required steps may be different. For details, see the
7825 manual pages for @command{mkswap} and @command{swapon}.}:
7828 # This is 10 GiB of swap space. Adjust "count" to change the size.
7829 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7830 # For security, make the file readable and writable only by root.
7831 chmod 600 /mnt/swapfile
7832 mkswap /mnt/swapfile
7833 swapon /mnt/swapfile
7836 Note that if you have encrypted the root partition and created a swap
7837 file in its file system as described above, then the encryption also
7838 protects the swap file, just like any other file in that file system.
7840 @node Proceeding with the Installation
7841 @subsection Proceeding with the Installation
7843 With the target partitions ready and the target root mounted on
7844 @file{/mnt}, we're ready to go. First, run:
7847 herd start cow-store /mnt
7850 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7851 during the installation phase are written to the target disk on @file{/mnt}
7852 rather than kept in memory. This is necessary because the first phase of
7853 the @command{guix system init} command (see below) entails downloads or
7854 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7856 Next, you have to edit a file and
7857 provide the declaration of the operating system to be installed. To
7858 that end, the installation system comes with three text editors: GNU nano
7859 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7860 nvi (a clone of the original BSD @command{vi} editor).
7861 We strongly recommend storing that file on the target root file system, say,
7862 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7863 configuration file once you have rebooted into the newly-installed system.
7865 @xref{Using the Configuration System}, for an overview of the
7866 configuration file. The example configurations discussed in that
7867 section are available under @file{/etc/configuration} in the
7868 installation image. Thus, to get started with a system configuration
7869 providing a graphical display server (a ``desktop'' system), you can run
7870 something along these lines:
7874 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7875 # zile /mnt/etc/config.scm
7878 You should pay attention to what your configuration file contains, and
7883 Make sure the @code{grub-configuration} form refers to the device you
7884 want to install GRUB on. You also need to specify the @code{grub-efi}
7885 package if you wish to use native UEFI boot.
7888 Be sure that your partition labels match the value of their respective
7889 @code{device} fields in your @code{file-system} configuration, assuming
7890 your @code{file-system} configuration sets the value of @code{title} to
7894 If there are encrypted or RAID partitions, make sure to add a
7895 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7898 Once you are done preparing the configuration file, the new system must
7899 be initialized (remember that the target root file system is mounted
7903 guix system init /mnt/etc/config.scm /mnt
7907 This copies all the necessary files and installs GRUB on
7908 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7909 more information, @pxref{Invoking guix system}. This command may trigger
7910 downloads or builds of missing packages, which can take some time.
7912 Once that command has completed---and hopefully succeeded!---you can run
7913 @command{reboot} and boot into the new system. The @code{root} password
7914 in the new system is initially empty; other users' passwords need to be
7915 initialized by running the @command{passwd} command as @code{root},
7916 unless your configuration specifies otherwise
7917 (@pxref{user-account-password, user account passwords}).
7919 @cindex upgrading GuixSD
7920 From then on, you can update GuixSD whenever you want by running
7921 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7922 then running @command{guix system reconfigure} to build a new system
7923 generation with the latest packages and services (@pxref{Invoking guix
7924 system}). We recommend doing that regularly so that your system
7925 includes the latest security updates (@pxref{Security Updates}).
7927 Join us on @code{#guix} on the Freenode IRC network or on
7928 @file{guix-devel@@gnu.org} to share your experience---good or not so
7931 @node Installing GuixSD in a VM
7932 @subsection Installing GuixSD in a Virtual Machine
7934 @cindex virtual machine, GuixSD installation
7935 @cindex virtual private server (VPS)
7936 @cindex VPS (virtual private server)
7937 If you'd like to install GuixSD in a virtual machine (VM) or on a
7938 virtual private server (VPS) rather than on your beloved machine, this
7941 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7942 disk image, follow these steps:
7946 First, retrieve and decompress the GuixSD installation image as
7947 described previously (@pxref{USB Stick Installation}).
7950 Create a disk image that will hold the installed system. To make a
7951 qcow2-formatted disk image, use the @command{qemu-img} command:
7954 qemu-img create -f qcow2 guixsd.img 50G
7957 The resulting file will be much smaller than 50 GB (typically less than
7958 1 MB), but it will grow as the virtualized storage device is filled up.
7961 Boot the USB installation image in an VM:
7964 qemu-system-x86_64 -m 1024 -smp 1 \
7965 -net user -net nic,model=virtio -boot menu=on \
7966 -drive file=guixsd-usb-install-@value{VERSION}.@var{system} \
7967 -drive file=guixsd.img
7970 The ordering of the drives matters.
7972 In the VM console, quickly press the @kbd{F12} key to enter the boot
7973 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7977 You're now root in the VM, proceed with the installation process.
7978 @xref{Preparing for Installation}, and follow the instructions.
7981 Once installation is complete, you can boot the system that's on your
7982 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
7985 @node Building the Installation Image
7986 @subsection Building the Installation Image
7988 @cindex installation image
7989 The installation image described above was built using the @command{guix
7990 system} command, specifically:
7993 guix system disk-image gnu/system/install.scm
7996 Have a look at @file{gnu/system/install.scm} in the source tree,
7997 and see also @ref{Invoking guix system} for more information
7998 about the installation image.
8000 @node System Configuration
8001 @section System Configuration
8003 @cindex system configuration
8004 The Guix System Distribution supports a consistent whole-system configuration
8005 mechanism. By that we mean that all aspects of the global system
8006 configuration---such as the available system services, timezone and
8007 locale settings, user accounts---are declared in a single place. Such
8008 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
8010 One of the advantages of putting all the system configuration under the
8011 control of Guix is that it supports transactional system upgrades, and
8012 makes it possible to roll back to a previous system instantiation,
8013 should something go wrong with the new one (@pxref{Features}). Another
8014 advantage is that it makes it easy to replicate the exact same configuration
8015 across different machines, or at different points in time, without
8016 having to resort to additional administration tools layered on top of
8017 the own tools of the system.
8018 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
8020 This section describes this mechanism. First we focus on the system
8021 administrator's viewpoint---explaining how the system is configured and
8022 instantiated. Then we show how this mechanism can be extended, for
8023 instance to support new system services.
8026 * Using the Configuration System:: Customizing your GNU system.
8027 * operating-system Reference:: Detail of operating-system declarations.
8028 * File Systems:: Configuring file system mounts.
8029 * Mapped Devices:: Block device extra processing.
8030 * User Accounts:: Specifying user accounts.
8031 * Locales:: Language and cultural convention settings.
8032 * Services:: Specifying system services.
8033 * Setuid Programs:: Programs running with root privileges.
8034 * X.509 Certificates:: Authenticating HTTPS servers.
8035 * Name Service Switch:: Configuring libc's name service switch.
8036 * Initial RAM Disk:: Linux-Libre bootstrapping.
8037 * Bootloader Configuration:: Configuring the boot loader.
8038 * Invoking guix system:: Instantiating a system configuration.
8039 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
8040 * Defining Services:: Adding new service definitions.
8043 @node Using the Configuration System
8044 @subsection Using the Configuration System
8046 The operating system is configured by providing an
8047 @code{operating-system} declaration in a file that can then be passed to
8048 the @command{guix system} command (@pxref{Invoking guix system}). A
8049 simple setup, with the default system services, the default Linux-Libre
8050 kernel, initial RAM disk, and boot loader looks like this:
8052 @findex operating-system
8054 @include os-config-bare-bones.texi
8057 This example should be self-describing. Some of the fields defined
8058 above, such as @code{host-name} and @code{bootloader}, are mandatory.
8059 Others, such as @code{packages} and @code{services}, can be omitted, in
8060 which case they get a default value.
8062 Below we discuss the effect of some of the most important fields
8063 (@pxref{operating-system Reference}, for details about all the available
8064 fields), and how to @dfn{instantiate} the operating system using
8065 @command{guix system}.
8067 @unnumberedsubsubsec Globally-Visible Packages
8069 @vindex %base-packages
8070 The @code{packages} field lists packages that will be globally visible
8071 on the system, for all user accounts---i.e., in every user's @code{PATH}
8072 environment variable---in addition to the per-user profiles
8073 (@pxref{Invoking guix package}). The @var{%base-packages} variable
8074 provides all the tools one would expect for basic user and administrator
8075 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
8076 the GNU Zile lightweight text editor, @command{find}, @command{grep},
8077 etc. The example above adds tcpdump to those, taken from the @code{(gnu
8078 packages admin)} module (@pxref{Package Modules}). The
8079 @code{(list package output)} syntax can be used to add a specific output
8083 (use-modules (gnu packages))
8084 (use-modules (gnu packages dns))
8088 (packages (cons (list bind "utils")
8092 @findex specification->package
8093 Referring to packages by variable name, like @var{tcpdump} above, has
8094 the advantage of being unambiguous; it also allows typos and such to be
8095 diagnosed right away as ``unbound variables''. The downside is that one
8096 needs to know which module defines which package, and to augment the
8097 @code{use-package-modules} line accordingly. To avoid that, one can use
8098 the @code{specification->package} procedure of the @code{(gnu packages)}
8099 module, which returns the best package for a given name or name and
8103 (use-modules (gnu packages))
8107 (packages (append (map specification->package
8108 '("tcpdump" "htop" "gnupg@@2.0"))
8112 @unnumberedsubsubsec System Services
8115 @vindex %base-services
8116 The @code{services} field lists @dfn{system services} to be made
8117 available when the system starts (@pxref{Services}).
8118 The @code{operating-system} declaration above specifies that, in
8119 addition to the basic services, we want the @command{lshd} secure shell
8120 daemon listening on port 2222 (@pxref{Networking Services,
8121 @code{lsh-service}}). Under the hood,
8122 @code{lsh-service} arranges so that @code{lshd} is started with the
8123 right command-line options, possibly with supporting configuration files
8124 generated as needed (@pxref{Defining Services}).
8126 @cindex customization, of services
8127 @findex modify-services
8128 Occasionally, instead of using the base services as is, you will want to
8129 customize them. To do this, use @code{modify-services} (@pxref{Service
8130 Reference, @code{modify-services}}) to modify the list.
8132 For example, suppose you want to modify @code{guix-daemon} and Mingetty
8133 (the console log-in) in the @var{%base-services} list (@pxref{Base
8134 Services, @code{%base-services}}). To do that, you can write the
8135 following in your operating system declaration:
8138 (define %my-services
8139 ;; My very own list of services.
8140 (modify-services %base-services
8141 (guix-service-type config =>
8144 (use-substitutes? #f)
8145 (extra-options '("--gc-keep-derivations"))))
8146 (mingetty-service-type config =>
8147 (mingetty-configuration
8148 (inherit config)))))
8152 (services %my-services))
8155 This changes the configuration---i.e., the service parameters---of the
8156 @code{guix-service-type} instance, and that of all the
8157 @code{mingetty-service-type} instances in the @var{%base-services} list.
8158 Observe how this is accomplished: first, we arrange for the original
8159 configuration to be bound to the identifier @code{config} in the
8160 @var{body}, and then we write the @var{body} so that it evaluates to the
8161 desired configuration. In particular, notice how we use @code{inherit}
8162 to create a new configuration which has the same values as the old
8163 configuration, but with a few modifications.
8165 @cindex encrypted disk
8166 The configuration for a typical ``desktop'' usage, with an encrypted
8167 root partition, the X11 display
8168 server, GNOME and Xfce (users can choose which of these desktop
8169 environments to use at the log-in screen by pressing @kbd{F1}), network
8170 management, power management, and more, would look like this:
8173 @include os-config-desktop.texi
8176 A graphical UEFI system with a choice of lightweight window managers
8177 instead of full-blown desktop environments would look like this:
8180 @include os-config-lightweight-desktop.texi
8183 @xref{Desktop Services}, for the exact list of services provided by
8184 @var{%desktop-services}. @xref{X.509 Certificates}, for background
8185 information about the @code{nss-certs} package that is used here.
8187 Again, @var{%desktop-services} is just a list of service objects. If
8188 you want to remove services from there, you can do so using the
8189 procedures for list filtering (@pxref{SRFI-1 Filtering and
8190 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
8191 following expression returns a list that contains all the services in
8192 @var{%desktop-services} minus the Avahi service:
8195 (remove (lambda (service)
8196 (eq? (service-kind service) avahi-service-type))
8200 @unnumberedsubsubsec Instantiating the System
8202 Assuming the @code{operating-system} declaration
8203 is stored in the @file{my-system-config.scm}
8204 file, the @command{guix system reconfigure my-system-config.scm} command
8205 instantiates that configuration, and makes it the default GRUB boot
8206 entry (@pxref{Invoking guix system}).
8208 The normal way to change the system configuration is by updating this
8209 file and re-running @command{guix system reconfigure}. One should never
8210 have to touch files in @file{/etc} or to run commands that modify the
8211 system state such as @command{useradd} or @command{grub-install}. In
8212 fact, you must avoid that since that would not only void your warranty
8213 but also prevent you from rolling back to previous versions of your
8214 system, should you ever need to.
8216 @cindex roll-back, of the operating system
8217 Speaking of roll-back, each time you run @command{guix system
8218 reconfigure}, a new @dfn{generation} of the system is created---without
8219 modifying or deleting previous generations. Old system generations get
8220 an entry in the bootloader boot menu, allowing you to boot them in case
8221 something went wrong with the latest generation. Reassuring, no? The
8222 @command{guix system list-generations} command lists the system
8223 generations available on disk. It is also possible to roll back the
8224 system via the commands @command{guix system roll-back} and
8225 @command{guix system switch-generation}.
8227 Although the command @command{guix system reconfigure} will not modify
8228 previous generations, must take care when the current generation is not
8229 the latest (e.g., after invoking @command{guix system roll-back}), since
8230 the operation might overwrite a later generation (@pxref{Invoking guix
8233 @unnumberedsubsubsec The Programming Interface
8235 At the Scheme level, the bulk of an @code{operating-system} declaration
8236 is instantiated with the following monadic procedure (@pxref{The Store
8239 @deffn {Monadic Procedure} operating-system-derivation os
8240 Return a derivation that builds @var{os}, an @code{operating-system}
8241 object (@pxref{Derivations}).
8243 The output of the derivation is a single directory that refers to all
8244 the packages, configuration files, and other supporting files needed to
8245 instantiate @var{os}.
8248 This procedure is provided by the @code{(gnu system)} module. Along
8249 with @code{(gnu services)} (@pxref{Services}), this module contains the
8250 guts of GuixSD. Make sure to visit it!
8253 @node operating-system Reference
8254 @subsection @code{operating-system} Reference
8256 This section summarizes all the options available in
8257 @code{operating-system} declarations (@pxref{Using the Configuration
8260 @deftp {Data Type} operating-system
8261 This is the data type representing an operating system configuration.
8262 By that, we mean all the global system configuration, not per-user
8263 configuration (@pxref{Using the Configuration System}).
8266 @item @code{kernel} (default: @var{linux-libre})
8267 The package object of the operating system kernel to use@footnote{Currently
8268 only the Linux-libre kernel is supported. In the future, it will be
8269 possible to use the GNU@tie{}Hurd.}.
8271 @item @code{kernel-arguments} (default: @code{'()})
8272 List of strings or gexps representing additional arguments to pass on
8273 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
8275 @item @code{bootloader}
8276 The system bootloader configuration object. @xref{Bootloader Configuration}.
8278 @item @code{initrd} (default: @code{base-initrd})
8280 @cindex initial RAM disk
8281 A two-argument monadic procedure that returns an initial RAM disk for
8282 the Linux kernel. @xref{Initial RAM Disk}.
8284 @item @code{firmware} (default: @var{%base-firmware})
8286 List of firmware packages loadable by the operating system kernel.
8288 The default includes firmware needed for Atheros- and Broadcom-based
8289 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
8290 respectively). @xref{Hardware Considerations}, for more info on
8293 @item @code{host-name}
8296 @item @code{hosts-file}
8298 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
8299 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
8300 Reference Manual}). The default is a file with entries for
8301 @code{localhost} and @var{host-name}.
8303 @item @code{mapped-devices} (default: @code{'()})
8304 A list of mapped devices. @xref{Mapped Devices}.
8306 @item @code{file-systems}
8307 A list of file systems. @xref{File Systems}.
8309 @item @code{swap-devices} (default: @code{'()})
8310 @cindex swap devices
8311 A list of strings identifying devices or files to be used for ``swap
8312 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
8313 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
8314 It is possible to specify a swap file in a file system on a mapped
8315 device, provided that the necessary device mapping and file system are
8316 also specified. @xref{Mapped Devices} and @ref{File Systems}.
8318 @item @code{users} (default: @code{%base-user-accounts})
8319 @itemx @code{groups} (default: @var{%base-groups})
8320 List of user accounts and groups. @xref{User Accounts}.
8322 @item @code{skeletons} (default: @code{(default-skeletons)})
8323 A list target file name/file-like object tuples (@pxref{G-Expressions,
8324 file-like objects}). These are the skeleton files that will be added to
8325 the home directory of newly-created user accounts.
8327 For instance, a valid value may look like this:
8330 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
8331 (".guile" ,(plain-file "guile"
8332 "(use-modules (ice-9 readline))
8333 (activate-readline)")))
8336 @item @code{issue} (default: @var{%default-issue})
8337 A string denoting the contents of the @file{/etc/issue} file, which is
8338 displayed when users log in on a text console.
8340 @item @code{packages} (default: @var{%base-packages})
8341 The set of packages installed in the global profile, which is accessible
8342 at @file{/run/current-system/profile}.
8344 The default set includes core utilities and it is good practice to
8345 install non-core utilities in user profiles (@pxref{Invoking guix
8348 @item @code{timezone}
8349 A timezone identifying string---e.g., @code{"Europe/Paris"}.
8351 You can run the @command{tzselect} command to find out which timezone
8352 string corresponds to your region. Choosing an invalid timezone name
8353 causes @command{guix system} to fail.
8355 @item @code{locale} (default: @code{"en_US.utf8"})
8356 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
8357 Library Reference Manual}). @xref{Locales}, for more information.
8359 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
8360 The list of locale definitions to be compiled and that may be used at
8361 run time. @xref{Locales}.
8363 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
8364 The list of GNU@tie{}libc packages whose locale data and tools are used
8365 to build the locale definitions. @xref{Locales}, for compatibility
8366 considerations that justify this option.
8368 @item @code{name-service-switch} (default: @var{%default-nss})
8369 Configuration of the libc name service switch (NSS)---a
8370 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
8373 @item @code{services} (default: @var{%base-services})
8374 A list of service objects denoting system services. @xref{Services}.
8376 @item @code{pam-services} (default: @code{(base-pam-services)})
8378 @cindex pluggable authentication modules
8379 Linux @dfn{pluggable authentication module} (PAM) services.
8380 @c FIXME: Add xref to PAM services section.
8382 @item @code{setuid-programs} (default: @var{%setuid-programs})
8383 List of string-valued G-expressions denoting setuid programs.
8384 @xref{Setuid Programs}.
8386 @item @code{sudoers-file} (default: @var{%sudoers-specification})
8387 @cindex sudoers file
8388 The contents of the @file{/etc/sudoers} file as a file-like object
8389 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
8391 This file specifies which users can use the @command{sudo} command, what
8392 they are allowed to do, and what privileges they may gain. The default
8393 is that only @code{root} and members of the @code{wheel} group may use
8400 @subsection File Systems
8402 The list of file systems to be mounted is specified in the
8403 @code{file-systems} field of the operating system declaration
8404 (@pxref{Using the Configuration System}). Each file system is declared
8405 using the @code{file-system} form, like this:
8409 (mount-point "/home")
8410 (device "/dev/sda3")
8414 As usual, some of the fields are mandatory---those shown in the example
8415 above---while others can be omitted. These are described below.
8417 @deftp {Data Type} file-system
8418 Objects of this type represent file systems to be mounted. They
8419 contain the following members:
8423 This is a string specifying the type of the file system---e.g.,
8426 @item @code{mount-point}
8427 This designates the place where the file system is to be mounted.
8430 This names the ``source'' of the file system. By default it is the name
8431 of a node under @file{/dev}, but its meaning depends on the @code{title}
8432 field described below.
8434 @item @code{title} (default: @code{'device})
8435 This is a symbol that specifies how the @code{device} field is to be
8438 When it is the symbol @code{device}, then the @code{device} field is
8439 interpreted as a file name; when it is @code{label}, then @code{device}
8440 is interpreted as a partition label name; when it is @code{uuid},
8441 @code{device} is interpreted as a partition unique identifier (UUID).
8443 UUIDs may be converted from their string representation (as shown by the
8444 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8445 @code{uuid} form expects 16-byte UUIDs as defined in
8446 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8447 form of UUID used by the ext2 family of file systems and others, but it
8448 is different from ``UUIDs'' found in FAT file systems, for instance.},
8453 (mount-point "/home")
8456 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8459 The @code{label} and @code{uuid} options offer a way to refer to disk
8460 partitions without having to hard-code their actual device
8461 name@footnote{Note that, while it is tempting to use
8462 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8463 result, this is not recommended: These special device nodes are created
8464 by the udev daemon and may be unavailable at the time the device is
8467 However, when the source of a file system is a mapped device (@pxref{Mapped
8468 Devices}), its @code{device} field @emph{must} refer to the mapped
8469 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8470 @code{title} must be set to @code{'device}. This is required so that
8471 the system knows that mounting the file system depends on having the
8472 corresponding device mapping established.
8474 @item @code{flags} (default: @code{'()})
8475 This is a list of symbols denoting mount flags. Recognized flags
8476 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8477 access to special files), @code{no-suid} (ignore setuid and setgid
8478 bits), and @code{no-exec} (disallow program execution.)
8480 @item @code{options} (default: @code{#f})
8481 This is either @code{#f}, or a string denoting mount options.
8483 @item @code{mount?} (default: @code{#t})
8484 This value indicates whether to automatically mount the file system when
8485 the system is brought up. When set to @code{#f}, the file system gets
8486 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8487 is not automatically mounted.
8489 @item @code{needed-for-boot?} (default: @code{#f})
8490 This Boolean value indicates whether the file system is needed when
8491 booting. If that is true, then the file system is mounted when the
8492 initial RAM disk (initrd) is loaded. This is always the case, for
8493 instance, for the root file system.
8495 @item @code{check?} (default: @code{#t})
8496 This Boolean indicates whether the file system needs to be checked for
8497 errors before being mounted.
8499 @item @code{create-mount-point?} (default: @code{#f})
8500 When true, the mount point is created if it does not exist yet.
8502 @item @code{dependencies} (default: @code{'()})
8503 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8504 representing file systems that must be mounted or mapped devices that
8505 must be opened before (and unmounted or closed after) this one.
8507 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8508 a dependency of @file{/sys/fs/cgroup/cpu} and
8509 @file{/sys/fs/cgroup/memory}.
8511 Another example is a file system that depends on a mapped device, for
8512 example for an encrypted partition (@pxref{Mapped Devices}).
8516 The @code{(gnu system file-systems)} exports the following useful
8519 @defvr {Scheme Variable} %base-file-systems
8520 These are essential file systems that are required on normal systems,
8521 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8522 below.) Operating system declarations should always contain at least
8526 @defvr {Scheme Variable} %pseudo-terminal-file-system
8527 This is the file system to be mounted as @file{/dev/pts}. It supports
8528 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8529 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8530 Manual}). Pseudo-terminals are used by terminal emulators such as
8534 @defvr {Scheme Variable} %shared-memory-file-system
8535 This file system is mounted as @file{/dev/shm} and is used to support
8536 memory sharing across processes (@pxref{Memory-mapped I/O,
8537 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8540 @defvr {Scheme Variable} %immutable-store
8541 This file system performs a read-only ``bind mount'' of
8542 @file{/gnu/store}, making it read-only for all the users including
8543 @code{root}. This prevents against accidental modification by software
8544 running as @code{root} or by system administrators.
8546 The daemon itself is still able to write to the store: it remounts it
8547 read-write in its own ``name space.''
8550 @defvr {Scheme Variable} %binary-format-file-system
8551 The @code{binfmt_misc} file system, which allows handling of arbitrary
8552 executable file types to be delegated to user space. This requires the
8553 @code{binfmt.ko} kernel module to be loaded.
8556 @defvr {Scheme Variable} %fuse-control-file-system
8557 The @code{fusectl} file system, which allows unprivileged users to mount
8558 and unmount user-space FUSE file systems. This requires the
8559 @code{fuse.ko} kernel module to be loaded.
8562 @node Mapped Devices
8563 @subsection Mapped Devices
8565 @cindex device mapping
8566 @cindex mapped devices
8567 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8568 such as a hard disk partition, can be @dfn{mapped} into another device,
8569 usually in @code{/dev/mapper/},
8570 with additional processing over the data that flows through
8571 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8572 concept of a ``mapped device'' and that of a file system: both boil down
8573 to @emph{translating} input/output operations made on a file to
8574 operations on its backing store. Thus, the Hurd implements mapped
8575 devices, like file systems, using the generic @dfn{translator} mechanism
8576 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8577 typical example is encryption device mapping: all writes to the mapped
8578 device are encrypted, and all reads are deciphered, transparently.
8579 Guix extends this notion by considering any device or set of devices that
8580 are @dfn{transformed} in some way to create a new device; for instance,
8581 RAID devices are obtained by @dfn{assembling} several other devices, such
8582 as hard disks or partitions, into a new one that behaves as one partition.
8583 Other examples, not yet implemented, are LVM logical volumes.
8585 Mapped devices are declared using the @code{mapped-device} form,
8586 defined as follows; for examples, see below.
8588 @deftp {Data Type} mapped-device
8589 Objects of this type represent device mappings that will be made when
8590 the system boots up.
8594 This is either a string specifying the name of the block device to be mapped,
8595 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8596 need to be assembled for creating a new one.
8599 This string specifies the name of the resulting mapped device. For
8600 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8601 specifying @code{"my-partition"} leads to the creation of
8602 the @code{"/dev/mapper/my-partition"} device.
8603 For RAID devices of type @code{raid-device-mapping}, the full device name
8604 such as @code{"/dev/md0"} needs to be given.
8607 This must be a @code{mapped-device-kind} object, which specifies how
8608 @var{source} is mapped to @var{target}.
8612 @defvr {Scheme Variable} luks-device-mapping
8613 This defines LUKS block device encryption using the @command{cryptsetup}
8614 command from the package with the same name. It relies on the
8615 @code{dm-crypt} Linux kernel module.
8618 @defvr {Scheme Variable} raid-device-mapping
8619 This defines a RAID device, which is assembled using the @code{mdadm}
8620 command from the package with the same name. It requires a Linux kernel
8621 module for the appropriate RAID level to be loaded, such as @code{raid456}
8622 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8625 @cindex disk encryption
8627 The following example specifies a mapping from @file{/dev/sda3} to
8628 @file{/dev/mapper/home} using LUKS---the
8629 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8630 standard mechanism for disk encryption.
8631 The @file{/dev/mapper/home}
8632 device can then be used as the @code{device} of a @code{file-system}
8633 declaration (@pxref{File Systems}).
8637 (source "/dev/sda3")
8639 (type luks-device-mapping))
8642 Alternatively, to become independent of device numbering, one may obtain
8643 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8647 cryptsetup luksUUID /dev/sda3
8650 and use it as follows:
8654 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8656 (type luks-device-mapping))
8659 @cindex swap encryption
8660 It is also desirable to encrypt swap space, since swap space may contain
8661 sensitive data. One way to accomplish that is to use a swap file in a
8662 file system on a device mapped via LUKS encryption. In this way, the
8663 swap file is encrypted because the entire device is encrypted.
8664 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8666 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8667 may be declared as follows:
8671 (source (list "/dev/sda1" "/dev/sdb1"))
8673 (type raid-device-mapping))
8676 The @file{/dev/md0} device can then be used as the @code{device} of a
8677 @code{file-system} declaration (@pxref{File Systems}).
8678 Note that the RAID level need not be given; it is chosen during the
8679 initial creation and formatting of the RAID device and is determined
8680 automatically later.
8684 @subsection User Accounts
8688 @cindex user accounts
8689 User accounts and groups are entirely managed through the
8690 @code{operating-system} declaration. They are specified with the
8691 @code{user-account} and @code{user-group} forms:
8697 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8699 "video" ;video devices such as webcams
8700 "cdrom")) ;the good ol' CD-ROM
8701 (comment "Bob's sister")
8702 (home-directory "/home/alice"))
8705 When booting or upon completion of @command{guix system reconfigure},
8706 the system ensures that only the user accounts and groups specified in
8707 the @code{operating-system} declaration exist, and with the specified
8708 properties. Thus, account or group creations or modifications made by
8709 directly invoking commands such as @command{useradd} are lost upon
8710 reconfiguration or reboot. This ensures that the system remains exactly
8713 @deftp {Data Type} user-account
8714 Objects of this type represent user accounts. The following members may
8719 The name of the user account.
8723 This is the name (a string) or identifier (a number) of the user group
8724 this account belongs to.
8726 @item @code{supplementary-groups} (default: @code{'()})
8727 Optionally, this can be defined as a list of group names that this
8730 @item @code{uid} (default: @code{#f})
8731 This is the user ID for this account (a number), or @code{#f}. In the
8732 latter case, a number is automatically chosen by the system when the
8735 @item @code{comment} (default: @code{""})
8736 A comment about the account, such as the account owner's full name.
8738 @item @code{home-directory}
8739 This is the name of the home directory for the account.
8741 @item @code{create-home-directory?} (default: @code{#t})
8742 Indicates whether the home directory of this account should be created
8743 if it does not exist yet.
8745 @item @code{shell} (default: Bash)
8746 This is a G-expression denoting the file name of a program to be used as
8747 the shell (@pxref{G-Expressions}).
8749 @item @code{system?} (default: @code{#f})
8750 This Boolean value indicates whether the account is a ``system''
8751 account. System accounts are sometimes treated specially; for instance,
8752 graphical login managers do not list them.
8754 @anchor{user-account-password}
8755 @item @code{password} (default: @code{#f})
8756 You would normally leave this field to @code{#f}, initialize user
8757 passwords as @code{root} with the @command{passwd} command, and then let
8758 users change it with @command{passwd}. Passwords set with
8759 @command{passwd} are of course preserved across reboot and
8762 If you @emph{do} want to have a preset password for an account, then
8763 this field must contain the encrypted password, as a string.
8764 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8765 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8766 Manual}, for information on Guile's @code{crypt} procedure.
8772 User group declarations are even simpler:
8775 (user-group (name "students"))
8778 @deftp {Data Type} user-group
8779 This type is for, well, user groups. There are just a few fields:
8783 The name of the group.
8785 @item @code{id} (default: @code{#f})
8786 The group identifier (a number). If @code{#f}, a new number is
8787 automatically allocated when the group is created.
8789 @item @code{system?} (default: @code{#f})
8790 This Boolean value indicates whether the group is a ``system'' group.
8791 System groups have low numerical IDs.
8793 @item @code{password} (default: @code{#f})
8794 What, user groups can have a password? Well, apparently yes. Unless
8795 @code{#f}, this field specifies the password of the group.
8800 For convenience, a variable lists all the basic user groups one may
8803 @defvr {Scheme Variable} %base-groups
8804 This is the list of basic user groups that users and/or packages expect
8805 to be present on the system. This includes groups such as ``root'',
8806 ``wheel'', and ``users'', as well as groups used to control access to
8807 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8810 @defvr {Scheme Variable} %base-user-accounts
8811 This is the list of basic system accounts that programs may expect to
8812 find on a GNU/Linux system, such as the ``nobody'' account.
8814 Note that the ``root'' account is not included here. It is a
8815 special-case and is automatically added whether or not it is specified.
8822 A @dfn{locale} defines cultural conventions for a particular language
8823 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8824 Reference Manual}). Each locale has a name that typically has the form
8825 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8826 @code{fr_LU.utf8} designates the locale for the French language, with
8827 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8829 @cindex locale definition
8830 Usually, you will want to specify the default locale for the machine
8831 using the @code{locale} field of the @code{operating-system} declaration
8832 (@pxref{operating-system Reference, @code{locale}}).
8834 The selected locale is automatically added to the @dfn{locale
8835 definitions} known to the system if needed, with its codeset inferred
8836 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8837 @code{UTF-8} codeset. Additional locale definitions can be specified in
8838 the @code{locale-definitions} slot of @code{operating-system}---this is
8839 useful, for instance, if the codeset could not be inferred from the
8840 locale name. The default set of locale definitions includes some widely
8841 used locales, but not all the available locales, in order to save space.
8843 For instance, to add the North Frisian locale for Germany, the value of
8847 (cons (locale-definition
8848 (name "fy_DE.utf8") (source "fy_DE"))
8849 %default-locale-definitions)
8852 Likewise, to save space, one might want @code{locale-definitions} to
8853 list only the locales that are actually used, as in:
8856 (list (locale-definition
8857 (name "ja_JP.eucjp") (source "ja_JP")
8858 (charset "EUC-JP")))
8862 The compiled locale definitions are available at
8863 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8864 version, which is the default location where the GNU@tie{}libc provided
8865 by Guix looks for locale data. This can be overridden using the
8866 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8867 @code{LOCPATH} and locale packages}).
8869 The @code{locale-definition} form is provided by the @code{(gnu system
8870 locale)} module. Details are given below.
8872 @deftp {Data Type} locale-definition
8873 This is the data type of a locale definition.
8878 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8879 Reference Manual}, for more information on locale names.
8882 The name of the source for that locale. This is typically the
8883 @code{@var{language}_@var{territory}} part of the locale name.
8885 @item @code{charset} (default: @code{"UTF-8"})
8886 The ``character set'' or ``code set'' for that locale,
8887 @uref{http://www.iana.org/assignments/character-sets, as defined by
8893 @defvr {Scheme Variable} %default-locale-definitions
8894 A list of commonly used UTF-8 locales, used as the default
8895 value of the @code{locale-definitions} field of @code{operating-system}
8899 @cindex normalized codeset in locale names
8900 These locale definitions use the @dfn{normalized codeset} for the part
8901 that follows the dot in the name (@pxref{Using gettextized software,
8902 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8903 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8907 @subsubsection Locale Data Compatibility Considerations
8909 @cindex incompatibility, of locale data
8910 @code{operating-system} declarations provide a @code{locale-libcs} field
8911 to specify the GNU@tie{}libc packages that are used to compile locale
8912 declarations (@pxref{operating-system Reference}). ``Why would I
8913 care?'', you may ask. Well, it turns out that the binary format of
8914 locale data is occasionally incompatible from one libc version to
8917 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8918 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8919 For instance, a program linked against libc version 2.21 is unable to
8920 read locale data produced with libc 2.22; worse, that program
8921 @emph{aborts} instead of simply ignoring the incompatible locale
8922 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8923 the incompatible locale data, which is already an improvement.}.
8924 Similarly, a program linked against libc 2.22 can read most, but not
8925 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8926 data is incompatible); thus calls to @code{setlocale} may fail, but
8927 programs will not abort.
8929 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8930 choose whether and when to upgrade software in their profiles, and might
8931 be using a libc version different from the one the system administrator
8932 used to build the system-wide locale data.
8934 Fortunately, unprivileged users can also install their own locale data
8935 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8936 @code{GUIX_LOCPATH} and locale packages}).
8938 Still, it is best if the system-wide locale data at
8939 @file{/run/current-system/locale} is built for all the libc versions
8940 actually in use on the system, so that all the programs can access
8941 it---this is especially crucial on a multi-user system. To do that, the
8942 administrator can specify several libc packages in the
8943 @code{locale-libcs} field of @code{operating-system}:
8946 (use-package-modules base)
8950 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8953 This example would lead to a system containing locale definitions for
8954 both libc 2.21 and the current version of libc in
8955 @file{/run/current-system/locale}.
8959 @subsection Services
8961 @cindex system services
8962 An important part of preparing an @code{operating-system} declaration is
8963 listing @dfn{system services} and their configuration (@pxref{Using the
8964 Configuration System}). System services are typically daemons launched
8965 when the system boots, or other actions needed at that time---e.g.,
8966 configuring network access.
8968 GuixSD has a broad definition of ``service'' (@pxref{Service
8969 Composition}), but many services are managed by the GNU@tie{}Shepherd
8970 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8971 command allows you to list the available services, show their status,
8972 start and stop them, or do other specific operations (@pxref{Jump
8973 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8979 The above command, run as @code{root}, lists the currently defined
8980 services. The @command{herd doc} command shows a synopsis of the given
8985 Run libc's name service cache daemon (nscd).
8988 The @command{start}, @command{stop}, and @command{restart} sub-commands
8989 have the effect you would expect. For instance, the commands below stop
8990 the nscd service and restart the Xorg display server:
8994 Service nscd has been stopped.
8995 # herd restart xorg-server
8996 Service xorg-server has been stopped.
8997 Service xorg-server has been started.
9000 The following sections document the available services, starting with
9001 the core services, that may be used in an @code{operating-system}
9005 * Base Services:: Essential system services.
9006 * Scheduled Job Execution:: The mcron service.
9007 * Log Rotation:: The rottlog service.
9008 * Networking Services:: Network setup, SSH daemon, etc.
9009 * X Window:: Graphical display.
9010 * Printing Services:: Local and remote printer support.
9011 * Desktop Services:: D-Bus and desktop services.
9012 * Database Services:: SQL databases.
9013 * Mail Services:: IMAP, POP3, SMTP, and all that.
9014 * Messaging Services:: Messaging services.
9015 * Monitoring Services:: Monitoring services.
9016 * Kerberos Services:: Kerberos services.
9017 * Web Services:: Web servers.
9018 * DNS Services:: DNS daemons.
9019 * VPN Services:: VPN daemons.
9020 * Network File System:: NFS related services.
9021 * Continuous Integration:: The Cuirass service.
9022 * Power management Services:: The TLP tool.
9023 * Miscellaneous Services:: Other services.
9027 @subsubsection Base Services
9029 The @code{(gnu services base)} module provides definitions for the basic
9030 services that one expects from the system. The services exported by
9031 this module are listed below.
9033 @defvr {Scheme Variable} %base-services
9034 This variable contains a list of basic services (@pxref{Service Types
9035 and Services}, for more information on service objects) one would
9036 expect from the system: a login service (mingetty) on each tty, syslogd,
9037 the libc name service cache daemon (nscd), the udev device manager, and
9040 This is the default value of the @code{services} field of
9041 @code{operating-system} declarations. Usually, when customizing a
9042 system, you will want to append services to @var{%base-services}, like
9046 (cons* (avahi-service) (lsh-service) %base-services)
9050 @defvr {Scheme Variable} special-files-service-type
9051 This is the service that sets up ``special files'' such as
9052 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
9054 The value associated with @code{special-files-service-type} services
9055 must be a list of tuples where the first element is the ``special file''
9056 and the second element is its target. By default it is:
9058 @cindex @file{/bin/sh}
9059 @cindex @file{sh}, in @file{/bin}
9061 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
9064 @cindex @file{/usr/bin/env}
9065 @cindex @file{env}, in @file{/usr/bin}
9066 If you want to add, say, @code{/usr/bin/env} to your system, you can
9070 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
9071 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
9074 Since this is part of @code{%base-services}, you can use
9075 @code{modify-services} to customize the set of special files
9076 (@pxref{Service Reference, @code{modify-services}}). But the simple way
9077 to add a special file is @i{via} the @code{extra-special-file} procedure
9081 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
9082 Use @var{target} as the ``special file'' @var{file}.
9084 For example, adding the following lines to the @code{services} field of
9085 your operating system declaration leads to a @file{/usr/bin/env}
9089 (extra-special-file "/usr/bin/env"
9090 (file-append coreutils "/bin/env"))
9094 @deffn {Scheme Procedure} host-name-service @var{name}
9095 Return a service that sets the host name to @var{name}.
9098 @deffn {Scheme Procedure} login-service @var{config}
9099 Return a service to run login according to @var{config}, a
9100 @code{<login-configuration>} object, which specifies the message of the day,
9104 @deftp {Data Type} login-configuration
9105 This is the data type representing the configuration of login.
9110 @cindex message of the day
9111 A file-like object containing the ``message of the day''.
9113 @item @code{allow-empty-passwords?} (default: @code{#t})
9114 Allow empty passwords by default so that first-time users can log in when
9115 the 'root' account has just been created.
9120 @deffn {Scheme Procedure} mingetty-service @var{config}
9121 Return a service to run mingetty according to @var{config}, a
9122 @code{<mingetty-configuration>} object, which specifies the tty to run, among
9126 @deftp {Data Type} mingetty-configuration
9127 This is the data type representing the configuration of Mingetty, which
9128 provides the default implementation of virtual console log-in.
9133 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
9135 @item @code{auto-login} (default: @code{#f})
9136 When true, this field must be a string denoting the user name under
9137 which the system automatically logs in. When it is @code{#f}, a
9138 user name and password must be entered to log in.
9140 @item @code{login-program} (default: @code{#f})
9141 This must be either @code{#f}, in which case the default log-in program
9142 is used (@command{login} from the Shadow tool suite), or a gexp denoting
9143 the name of the log-in program.
9145 @item @code{login-pause?} (default: @code{#f})
9146 When set to @code{#t} in conjunction with @var{auto-login}, the user
9147 will have to press a key before the log-in shell is launched.
9149 @item @code{mingetty} (default: @var{mingetty})
9150 The Mingetty package to use.
9155 @deffn {Scheme Procedure} agetty-service @var{config}
9156 Return a service to run agetty according to @var{config}, an
9157 @code{<agetty-configuration>} object, which specifies the tty to run,
9161 @deftp {Data Type} agetty-configuration
9162 This is the data type representing the configuration of agetty, which
9163 implements virtual and serial console log-in. See the @code{agetty(8)}
9164 man page for more information.
9169 The name of the console this agetty runs on, as a string---e.g.,
9170 @code{"ttyS0"}. This argument is mandatory.
9172 @item @code{baud-rate} (default: @code{#f})
9173 A string containing a comma-separated list of one or more baud rates, in
9176 @item @code{term} (default: @code{#f})
9177 A string containing the value used for the @code{TERM} environment
9180 @item @code{eight-bits?} (default: @code{#f})
9181 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
9184 @item @code{auto-login} (default: @code{#f})
9185 When passed a login name, as a string, the specified user will be logged
9186 in automatically without prompting for their login name or password.
9188 @item @code{no-reset?} (default: @code{#f})
9189 When @code{#t}, don't reset terminal cflags (control modes).
9191 @item @code{host} (default: @code{#f})
9192 This accepts a string containing the "login_host", which will be written
9193 into the @file{/var/run/utmpx} file.
9195 @item @code{remote?} (default: @code{#f})
9196 When set to @code{#t} in conjunction with @var{host}, this will add an
9197 @code{-r} fakehost option to the command line of the login program
9198 specified in @var{login-program}.
9200 @item @code{flow-control?} (default: @code{#f})
9201 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
9203 @item @code{no-issue?} (default: @code{#f})
9204 When set to @code{#t}, the contents of the @file{/etc/issue} file will
9205 not be displayed before presenting the login prompt.
9207 @item @code{init-string} (default: @code{#f})
9208 This accepts a string that will be sent to the tty or modem before
9209 sending anything else. It can be used to initialize a modem.
9211 @item @code{no-clear?} (default: @code{#f})
9212 When set to @code{#t}, agetty will not clear the screen before showing
9215 @item @code{login-program} (default: (file-append shadow "/bin/login"))
9216 This must be either a gexp denoting the name of a log-in program, or
9217 unset, in which case the default value is the @command{login} from the
9220 @item @code{local-line} (default: @code{#f})
9221 Control the CLOCAL line flag. This accepts one of three symbols as
9222 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
9223 the default value chosen by agetty is @code{'auto}.
9225 @item @code{extract-baud?} (default: @code{#f})
9226 When set to @code{#t}, instruct agetty to try to extract the baud rate
9227 from the status messages produced by certain types of modems.
9229 @item @code{skip-login?} (default: @code{#f})
9230 When set to @code{#t}, do not prompt the user for a login name. This
9231 can be used with @var{login-program} field to use non-standard login
9234 @item @code{no-newline?} (default: @code{#f})
9235 When set to @code{#t}, do not print a newline before printing the
9236 @file{/etc/issue} file.
9238 @c Is this dangerous only when used with login-program, or always?
9239 @item @code{login-options} (default: @code{#f})
9240 This option accepts a string containing options that are passed to the
9241 login program. When used with the @var{login-program}, be aware that a
9242 malicious user could try to enter a login name containing embedded
9243 options that could be parsed by the login program.
9245 @item @code{login-pause} (default: @code{#f})
9246 When set to @code{#t}, wait for any key before showing the login prompt.
9247 This can be used in conjunction with @var{auto-login} to save memory by
9248 lazily spawning shells.
9250 @item @code{chroot} (default: @code{#f})
9251 Change root to the specified directory. This option accepts a directory
9254 @item @code{hangup?} (default: @code{#f})
9255 Use the Linux system call @code{vhangup} to do a virtual hangup of the
9258 @item @code{keep-baud?} (default: @code{#f})
9259 When set to @code{#t}, try to keep the existing baud rate. The baud
9260 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
9263 @item @code{timeout} (default: @code{#f})
9264 When set to an integer value, terminate if no user name could be read
9265 within @var{timeout} seconds.
9267 @item @code{detect-case?} (default: @code{#f})
9268 When set to @code{#t}, turn on support for detecting an uppercase-only
9269 terminal. This setting will detect a login name containing only
9270 uppercase letters as indicating an uppercase-only terminal and turn on
9271 some upper-to-lower case conversions. Note that this will not support
9274 @item @code{wait-cr?} (default: @code{#f})
9275 When set to @code{#t}, wait for the user or modem to send a
9276 carriage-return or linefeed character before displaying
9277 @file{/etc/issue} or login prompt. This is typically used with the
9278 @var{init-string} option.
9280 @item @code{no-hints?} (default: @code{#f})
9281 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
9284 @item @code{no-hostname?} (default: @code{#f})
9285 By default, the hostname is printed. When this option is set to
9286 @code{#t}, no hostname will be shown at all.
9288 @item @code{long-hostname?} (default: @code{#f})
9289 By default, the hostname is only printed until the first dot. When this
9290 option is set to @code{#t}, the fully qualified hostname by
9291 @code{gethostname} or @code{getaddrinfo} is shown.
9293 @item @code{erase-characters} (default: @code{#f})
9294 This option accepts a string of additional characters that should be
9295 interpreted as backspace when the user types their login name.
9297 @item @code{kill-characters} (default: @code{#f})
9298 This option accepts a string that should be interpreted to mean "ignore
9299 all previous characters" (also called a "kill" character) when the types
9302 @item @code{chdir} (default: @code{#f})
9303 This option accepts, as a string, a directory path that will be changed
9306 @item @code{delay} (default: @code{#f})
9307 This options accepts, as an integer, the number of seconds to sleep
9308 before opening the tty and displaying the login prompt.
9310 @item @code{nice} (default: @code{#f})
9311 This option accepts, as an integer, the nice value with which to run the
9312 @command{login} program.
9314 @item @code{extra-options} (default: @code{'()})
9315 This option provides an "escape hatch" for the user to provide arbitrary
9316 command-line arguments to @command{agetty} as a list of strings.
9321 @deffn {Scheme Procedure} kmscon-service-type @var{config}
9322 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
9323 according to @var{config}, a @code{<kmscon-configuration>} object, which
9324 specifies the tty to run, among other things.
9327 @deftp {Data Type} kmscon-configuration
9328 This is the data type representing the configuration of Kmscon, which
9329 implements virtual console log-in.
9333 @item @code{virtual-terminal}
9334 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
9336 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
9337 A gexp denoting the name of the log-in program. The default log-in program is
9338 @command{login} from the Shadow tool suite.
9340 @item @code{login-arguments} (default: @code{'("-p")})
9341 A list of arguments to pass to @command{login}.
9343 @item @code{hardware-acceleration?} (default: #f)
9344 Whether to use hardware acceleration.
9346 @item @code{kmscon} (default: @var{kmscon})
9347 The Kmscon package to use.
9352 @cindex name service cache daemon
9354 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
9355 [#:name-services '()]
9356 Return a service that runs the libc name service cache daemon (nscd) with the
9357 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
9358 Service Switch}, for an example.
9361 @defvr {Scheme Variable} %nscd-default-configuration
9362 This is the default @code{<nscd-configuration>} value (see below) used
9363 by @code{nscd-service}. It uses the caches defined by
9364 @var{%nscd-default-caches}; see below.
9367 @deftp {Data Type} nscd-configuration
9368 This is the data type representing the name service cache daemon (nscd)
9373 @item @code{name-services} (default: @code{'()})
9374 List of packages denoting @dfn{name services} that must be visible to
9375 the nscd---e.g., @code{(list @var{nss-mdns})}.
9377 @item @code{glibc} (default: @var{glibc})
9378 Package object denoting the GNU C Library providing the @command{nscd}
9381 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
9382 Name of the nscd log file. This is where debugging output goes when
9383 @code{debug-level} is strictly positive.
9385 @item @code{debug-level} (default: @code{0})
9386 Integer denoting the debugging levels. Higher numbers mean that more
9387 debugging output is logged.
9389 @item @code{caches} (default: @var{%nscd-default-caches})
9390 List of @code{<nscd-cache>} objects denoting things to be cached; see
9396 @deftp {Data Type} nscd-cache
9397 Data type representing a cache database of nscd and its parameters.
9401 @item @code{database}
9402 This is a symbol representing the name of the database to be cached.
9403 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
9404 @code{services}, which designate the corresponding NSS database
9405 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
9407 @item @code{positive-time-to-live}
9408 @itemx @code{negative-time-to-live} (default: @code{20})
9409 A number representing the number of seconds during which a positive or
9410 negative lookup result remains in cache.
9412 @item @code{check-files?} (default: @code{#t})
9413 Whether to check for updates of the files corresponding to
9416 For instance, when @var{database} is @code{hosts}, setting this flag
9417 instructs nscd to check for updates in @file{/etc/hosts} and to take
9420 @item @code{persistent?} (default: @code{#t})
9421 Whether the cache should be stored persistently on disk.
9423 @item @code{shared?} (default: @code{#t})
9424 Whether the cache should be shared among users.
9426 @item @code{max-database-size} (default: 32@tie{}MiB)
9427 Maximum size in bytes of the database cache.
9429 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9430 @c settings, so leave them out.
9435 @defvr {Scheme Variable} %nscd-default-caches
9436 List of @code{<nscd-cache>} objects used by default by
9437 @code{nscd-configuration} (see above).
9439 It enables persistent and aggressive caching of service and host name
9440 lookups. The latter provides better host name lookup performance,
9441 resilience in the face of unreliable name servers, and also better
9442 privacy---often the result of host name lookups is in local cache, so
9443 external name servers do not even need to be queried.
9446 @anchor{syslog-configuration-type}
9449 @deftp {Data Type} syslog-configuration
9450 This data type represents the configuration of the syslog daemon.
9453 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9454 The syslog daemon to use.
9456 @item @code{config-file} (default: @code{%default-syslog.conf})
9457 The syslog configuration file to use.
9462 @anchor{syslog-service}
9464 @deffn {Scheme Procedure} syslog-service @var{config}
9465 Return a service that runs a syslog daemon according to @var{config}.
9467 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9468 information on the configuration file syntax.
9471 @anchor{guix-configuration-type}
9472 @deftp {Data Type} guix-configuration
9473 This data type represents the configuration of the Guix build daemon.
9474 @xref{Invoking guix-daemon}, for more information.
9477 @item @code{guix} (default: @var{guix})
9478 The Guix package to use.
9480 @item @code{build-group} (default: @code{"guixbuild"})
9481 Name of the group for build user accounts.
9483 @item @code{build-accounts} (default: @code{10})
9484 Number of build user accounts to create.
9486 @item @code{authorize-key?} (default: @code{#t})
9487 @cindex substitutes, authorization thereof
9488 Whether to authorize the substitute keys listed in
9489 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9490 (@pxref{Substitutes}).
9492 @vindex %default-authorized-guix-keys
9493 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9494 The list of authorized key files for archive imports, as a list of
9495 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9496 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9498 @item @code{use-substitutes?} (default: @code{#t})
9499 Whether to use substitutes.
9501 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9502 The list of URLs where to look for substitutes by default.
9504 @item @code{max-silent-time} (default: @code{0})
9505 @itemx @code{timeout} (default: @code{0})
9506 The number of seconds of silence and the number of seconds of activity,
9507 respectively, after which a build process times out. A value of zero
9508 disables the timeout.
9510 @item @code{extra-options} (default: @code{'()})
9511 List of extra command-line options for @command{guix-daemon}.
9513 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9514 File where @command{guix-daemon}'s standard output and standard error
9517 @item @code{lsof} (default: @var{lsof})
9518 The lsof package to use.
9520 @item @code{http-proxy} (default: @code{#f})
9521 The HTTP proxy used for downloading fixed-output derivations and
9524 @item @code{tmpdir} (default: @code{#f})
9525 A directory path where the @command{guix-daemon} will perform builds.
9530 @deffn {Scheme Procedure} guix-service @var{config}
9531 Return a service that runs the Guix build daemon according to
9535 @deffn {Scheme Procedure} udev-service [#:udev udev]
9536 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9539 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9540 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9544 @defvr {Scheme Variable} %random-seed-file
9545 This is the name of the file where some random bytes are saved by
9546 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9547 It defaults to @file{/var/lib/random-seed}.
9552 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9553 @cindex keyboard layout
9554 Return a service to load console keymaps from @var{files} using
9555 @command{loadkeys} command. Most likely, you want to load some default
9556 keymap, which can be done like this:
9559 (console-keymap-service "dvorak")
9562 Or, for example, for a Swedish keyboard, you may need to combine
9563 the following keymaps:
9565 (console-keymap-service "se-lat6" "se-fi-lat6")
9568 Also you can specify a full file name (or file names) of your keymap(s).
9569 See @code{man loadkeys} for details.
9575 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9577 Run @var{gpm}, the general-purpose mouse daemon, with the given
9578 command-line @var{options}. GPM allows users to use the mouse in the console,
9579 notably to select, copy, and paste text. The default value of @var{options}
9580 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9582 This service is not part of @var{%base-services}.
9585 @anchor{guix-publish-service-type}
9586 @deffn {Scheme Variable} guix-publish-service-type
9587 This is the service type for @command{guix publish} (@pxref{Invoking
9588 guix publish}). Its value must be a @code{guix-configuration}
9589 object, as described below.
9591 This assumes that @file{/etc/guix} already contains a signing key pair as
9592 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9593 archive}). If that is not the case, the service will fail to start.
9596 @deftp {Data Type} guix-publish-configuration
9597 Data type representing the configuration of the @code{guix publish}
9601 @item @code{guix} (default: @code{guix})
9602 The Guix package to use.
9604 @item @code{port} (default: @code{80})
9605 The TCP port to listen for connections.
9607 @item @code{host} (default: @code{"localhost"})
9608 The host (and thus, network interface) to listen to. Use
9609 @code{"0.0.0.0"} to listen on all the network interfaces.
9611 @item @code{compression-level} (default: @code{3})
9612 The gzip compression level at which substitutes are compressed. Use
9613 @code{0} to disable compression altogether, and @code{9} to get the best
9614 compression ratio at the expense of increased CPU usage.
9616 @item @code{nar-path} (default: @code{"nar"})
9617 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9618 publish, @code{--nar-path}}, for details.
9620 @item @code{cache} (default: @code{#f})
9621 When it is @code{#f}, disable caching and instead generate archives on
9622 demand. Otherwise, this should be the name of a directory---e.g.,
9623 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
9624 archives and meta-data ready to be sent. @xref{Invoking guix publish,
9625 @option{--cache}}, for more information on the tradeoffs involved.
9627 @item @code{workers} (default: @code{#f})
9628 When it is an integer, this is the number of worker threads used for
9629 caching; when @code{#f}, the number of processors is used.
9630 @xref{Invoking guix publish, @option{--workers}}, for more information.
9632 @item @code{ttl} (default: @code{#f})
9633 When it is an integer, this denotes the @dfn{time-to-live} of the
9634 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
9639 @anchor{rngd-service}
9640 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9641 [#:device "/dev/hwrng"]
9642 Return a service that runs the @command{rngd} program from @var{rng-tools}
9643 to add @var{device} to the kernel's entropy pool. The service will fail if
9644 @var{device} does not exist.
9647 @anchor{pam-limits-service}
9648 @cindex session limits
9651 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9653 Return a service that installs a configuration file for the
9654 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9655 @code{pam_limits} module}. The procedure optionally takes a list of
9656 @code{pam-limits-entry} values, which can be used to specify
9657 @code{ulimit} limits and nice priority limits to user sessions.
9659 The following limits definition sets two hard and soft limits for all
9660 login sessions of users in the @code{realtime} group:
9665 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9666 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9669 The first entry increases the maximum realtime priority for
9670 non-privileged processes; the second entry lifts any restriction of the
9671 maximum address space that can be locked in memory. These settings are
9672 commonly used for real-time audio systems.
9675 @node Scheduled Job Execution
9676 @subsubsection Scheduled Job Execution
9680 @cindex scheduling jobs
9681 The @code{(gnu services mcron)} module provides an interface to
9682 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9683 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9684 Unix @command{cron} daemon; the main difference is that it is
9685 implemented in Guile Scheme, which provides a lot of flexibility when
9686 specifying the scheduling of jobs and their actions.
9688 The example below defines an operating system that runs the
9689 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9690 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9691 well as the @command{mkid} command on behalf of an unprivileged user
9692 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9693 gexps to introduce job definitions that are passed to mcron
9694 (@pxref{G-Expressions}).
9697 (use-modules (guix) (gnu) (gnu services mcron))
9698 (use-package-modules base idutils)
9700 (define updatedb-job
9701 ;; Run 'updatedb' at 3AM every day. Here we write the
9702 ;; job's action as a Scheme procedure.
9703 #~(job '(next-hour '(3))
9705 (execl (string-append #$findutils "/bin/updatedb")
9707 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9709 (define garbage-collector-job
9710 ;; Collect garbage 5 minutes after midnight every day.
9711 ;; The job's action is a shell command.
9712 #~(job "5 0 * * *" ;Vixie cron syntax
9716 ;; Update the index database as user "charlie" at 12:15PM
9717 ;; and 19:15PM. This runs from the user's home directory.
9718 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9719 (string-append #$idutils "/bin/mkid src")
9724 (services (cons (mcron-service (list garbage-collector-job
9730 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9731 for more information on mcron job specifications. Below is the
9732 reference of the mcron service.
9734 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9735 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9736 list of gexps denoting mcron job specifications.
9738 This is a shorthand for:
9740 (service mcron-service-type
9741 (mcron-configuration (mcron mcron) (jobs jobs)))
9745 @defvr {Scheme Variable} mcron-service-type
9746 This is the type of the @code{mcron} service, whose value is an
9747 @code{mcron-configuration} object.
9749 This service type can be the target of a service extension that provides
9750 it additional job specifications (@pxref{Service Composition}). In
9751 other words, it is possible to define services that provide additional
9755 @deftp {Data Type} mcron-configuration
9756 Data type representing the configuration of mcron.
9759 @item @code{mcron} (default: @var{mcron2})
9760 The mcron package to use.
9763 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9764 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9765 specifications,, mcron, GNU@tie{}mcron}).
9771 @subsubsection Log Rotation
9774 @cindex log rotation
9776 Log files such as those found in @file{/var/log} tend to grow endlessly,
9777 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9778 their contents in separate files, possibly compressed. The @code{(gnu
9779 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9780 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9782 The example below defines an operating system that provides log rotation
9783 with the default settings, for commonly encountered log files.
9786 (use-modules (guix) (gnu))
9787 (use-service-modules admin mcron)
9788 (use-package-modules base idutils)
9792 (services (cons* (mcron-service)
9793 (service rottlog-service-type)
9797 @defvr {Scheme Variable} rottlog-service-type
9798 This is the type of the Rottlog service, whose value is a
9799 @code{rottlog-configuration} object.
9801 Other services can extend this one with new @code{log-rotation} objects
9802 (see below), thereby augmenting the set of files to be rotated.
9804 This service type can define mcron jobs (@pxref{Scheduled Job
9805 Execution}) to run the rottlog service.
9808 @deftp {Data Type} rottlog-configuration
9809 Data type representing the configuration of rottlog.
9812 @item @code{rottlog} (default: @code{rottlog})
9813 The Rottlog package to use.
9815 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9816 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9817 rottlog, GNU Rot[t]log Manual}).
9819 @item @code{rotations} (default: @code{%default-rotations})
9820 A list of @code{log-rotation} objects as defined below.
9823 This is a list of gexps where each gexp corresponds to an mcron job
9824 specification (@pxref{Scheduled Job Execution}).
9828 @deftp {Data Type} log-rotation
9829 Data type representing the rotation of a group of log files.
9831 Taking an example from the Rottlog manual (@pxref{Period Related File
9832 Examples,,, rottlog, GNU Rot[t]log Manual}), a log rotation might be
9838 (files '("/var/log/apache/*"))
9839 (options '("storedir apache-archives"
9845 The list of fields is as follows:
9848 @item @code{frequency} (default: @code{'weekly})
9849 The log rotation frequency, a symbol.
9852 The list of files or file glob patterns to rotate.
9854 @item @code{options} (default: @code{'()})
9855 The list of rottlog options for this rotation (@pxref{Configuration
9856 parameters,,, rottlog, GNU Rot[t]lg Manual}).
9858 @item @code{post-rotate} (default: @code{#f})
9859 Either @code{#f} or a gexp to execute once the rotation has completed.
9863 @defvr {Scheme Variable} %default-rotations
9864 Specifies weekly rotation of @var{%rotated-files} and
9865 a couple of other files.
9868 @defvr {Scheme Variable} %rotated-files
9869 The list of syslog-controlled files to be rotated. By default it is:
9870 @code{'("/var/log/messages" "/var/log/secure")}.
9873 @node Networking Services
9874 @subsubsection Networking Services
9876 The @code{(gnu services networking)} module provides services to configure
9877 the network interface.
9879 @cindex DHCP, networking service
9880 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9881 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9882 Protocol (DHCP) client, on all the non-loopback network interfaces.
9885 @defvr {Scheme Variable} static-networking-service-type
9886 This is the type for statically-configured network interfaces.
9887 @c TODO Document <static-networking> data structures.
9890 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9891 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9892 Return a service that starts @var{interface} with address @var{ip}. If
9893 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9894 it must be a string specifying the default network gateway.
9896 This procedure can be called several times, one for each network
9897 interface of interest. Behind the scenes what it does is extend
9898 @code{static-networking-service-type} with additional network interfaces
9905 @cindex network management
9906 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9907 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9908 management daemon that aims to simplify wired and wireless networking.
9910 This service adds the @var{wicd} package to the global profile, providing
9911 several commands to interact with the daemon and configure networking:
9912 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
9913 and @command{wicd-curses} user interfaces.
9916 @cindex NetworkManager
9918 @defvr {Scheme Variable} network-manager-service-type
9919 This is the service type for the
9920 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
9921 service. The value for this service type is a
9922 @code{network-manager-configuration} record.
9925 @deftp {Data Type} network-manager-configuration
9926 Data type representing the configuration of NetworkManager.
9929 @item @code{network-manager} (default: @code{network-manager})
9930 The NetworkManager package to use.
9932 @item @code{dns} (default: @code{"default"})
9933 Processing mode for DNS, which affects how NetworkManager uses the
9934 @code{resolv.conf} configuration file.
9938 NetworkManager will update @code{resolv.conf} to reflect the nameservers
9939 provided by currently active connections.
9942 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
9943 using a "split DNS" configuration if you are connected to a VPN, and
9944 then update @code{resolv.conf} to point to the local nameserver.
9947 NetworkManager will not modify @code{resolv.conf}.
9954 @deffn {Scheme Variable} connman-service-type
9955 This is the service type to run @url{https://01.org/connman,Connman},
9956 a network connection manager.
9958 Its value must be an
9959 @code{connman-configuration} record as in this example:
9962 (service connman-service-type
9963 (connman-configuration
9967 See below for details about @code{connman-configuration}.
9970 @deftp {Data Type} connman-configuration
9971 Data Type representing the configuration of connman.
9974 @item @code{connman} (default: @var{connman})
9975 The connman package to use.
9977 @item @code{disable-vpn?} (default: @code{#f})
9978 When true, enable connman's vpn plugin.
9982 @cindex WPA Supplicant
9983 @defvr {Scheme Variable} wpa-supplicant-service-type
9984 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
9985 supplicant}, an authentication daemon required to authenticate against
9986 encrypted WiFi or ethernet networks. It is configured to listen for
9989 The value of this service is the @code{wpa-supplicant} package to use.
9990 Thus, it can be instantiated like this:
9993 (use-modules (gnu services networking))
9995 (service wpa-supplicant-service-type)
10000 @cindex real time clock
10001 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
10002 [#:servers @var{%ntp-servers}] @
10003 [#:allow-large-adjustment? #f]
10004 Return a service that runs the daemon from @var{ntp}, the
10005 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
10006 keep the system clock synchronized with that of @var{servers}.
10007 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
10008 make an initial adjustment of more than 1,000 seconds.
10011 @defvr {Scheme Variable} %ntp-servers
10012 List of host names used as the default NTP servers.
10016 @deffn {Scheme variable} inetd-service-type
10017 This service runs the @command{inetd} (@pxref{inetd invocation,,,
10018 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
10019 connections on internet sockets, and lazily starts the specified server
10020 program when a connection is made on one of these sockets.
10022 The value of this service is an @code{inetd-configuration} object. The
10023 following example configures the @command{inetd} daemon to provide the
10024 built-in @command{echo} service, as well as an smtp service which
10025 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
10026 gateway @code{hostname}:
10031 (inetd-configuration
10035 (socket-type 'stream)
10042 (socket-type 'stream)
10046 (program (file-append openssh "/bin/ssh"))
10048 '("ssh" "-qT" "-i" "/path/to/ssh_key"
10049 "-W" "smtp-server:25" "user@@hostname")))))
10052 See below for more details about @code{inetd-configuration}.
10055 @deftp {Data Type} inetd-configuration
10056 Data type representing the configuration of @command{inetd}.
10059 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
10060 The @command{inetd} executable to use.
10062 @item @code{entries} (default: @code{'()})
10063 A list of @command{inetd} service entries. Each entry should be created
10064 by the @code{inetd-entry} constructor.
10068 @deftp {Data Type} inetd-entry
10069 Data type representing an entry in the @command{inetd} configuration.
10070 Each entry corresponds to a socket where @command{inetd} will listen for
10074 @item @code{node} (default: @code{#f})
10075 Optional string, a comma-separated list of local addresses
10076 @command{inetd} should use when listening for this service.
10077 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
10078 description of all options.
10080 A string, the name must correspond to an entry in @code{/etc/services}.
10081 @item @code{socket-type}
10082 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
10084 @item @code{protocol}
10085 A string, must correspond to an entry in @code{/etc/protocols}.
10086 @item @code{wait?} (default: @code{#t})
10087 Whether @command{inetd} should wait for the server to exit before
10088 listening to new service requests.
10090 A string containing the user (and, optionally, group) name of the user
10091 as whom the server should run. The group name can be specified in a
10092 suffix, separated by a colon or period, i.e. @code{"user"},
10093 @code{"user:group"} or @code{"user.group"}.
10094 @item @code{program} (default: @code{"internal"})
10095 The server program which will serve the requests, or @code{"internal"}
10096 if @command{inetd} should use a built-in service.
10097 @item @code{arguments} (default: @code{'()})
10098 A list strings or file-like objects, which are the server program's
10099 arguments, starting with the zeroth argument, i.e. the name of the
10100 program itself. For @command{inetd}'s internal services, this entry
10101 must be @code{'()} or @code{'("internal")}.
10104 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
10105 detailed discussion of each configuration field.
10109 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
10110 Return a service to run the @uref{https://torproject.org, Tor} anonymous
10113 The daemon runs as the @code{tor} unprivileged user. It is passed
10114 @var{config-file}, a file-like object, with an additional @code{User tor} line
10115 and lines for hidden services added via @code{tor-hidden-service}. Run
10116 @command{man tor} for information about the configuration file.
10119 @cindex hidden service
10120 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
10121 Define a new Tor @dfn{hidden service} called @var{name} and implementing
10122 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
10125 '((22 "127.0.0.1:22")
10126 (80 "127.0.0.1:8080"))
10129 In this example, port 22 of the hidden service is mapped to local port 22, and
10130 port 80 is mapped to local port 8080.
10132 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
10133 the @file{hostname} file contains the @code{.onion} host name for the hidden
10136 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
10137 project's documentation} for more information.
10140 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
10141 [#:interface "127.0.0.1"] [#:port 6667] @
10142 [#:extra-settings ""]
10143 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
10144 acts as a gateway between IRC and chat networks.
10146 The daemon will listen to the interface corresponding to the IP address
10147 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
10148 local clients can connect, whereas @code{0.0.0.0} means that connections can
10149 come from any networking interface.
10151 In addition, @var{extra-settings} specifies a string to append to the
10152 configuration file.
10155 Furthermore, @code{(gnu services ssh)} provides the following services.
10159 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
10160 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
10161 [#:allow-empty-passwords? #f] [#:root-login? #f] @
10162 [#:syslog-output? #t] [#:x11-forwarding? #t] @
10163 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
10164 [#:public-key-authentication? #t] [#:initialize? #t]
10165 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
10166 @var{host-key} must designate a file containing the host key, and readable
10169 When @var{daemonic?} is true, @command{lshd} will detach from the
10170 controlling terminal and log its output to syslogd, unless one sets
10171 @var{syslog-output?} to false. Obviously, it also makes lsh-service
10172 depend on existence of syslogd service. When @var{pid-file?} is true,
10173 @command{lshd} writes its PID to the file called @var{pid-file}.
10175 When @var{initialize?} is true, automatically create the seed and host key
10176 upon service activation if they do not exist yet. This may take long and
10177 require interaction.
10179 When @var{initialize?} is false, it is up to the user to initialize the
10180 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
10181 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
10182 basics,,, lsh, LSH Manual}).
10184 When @var{interfaces} is empty, lshd listens for connections on all the
10185 network interfaces; otherwise, @var{interfaces} must be a list of host names
10188 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
10189 passwords, and @var{root-login?} specifies whether to accept log-ins as
10192 The other options should be self-descriptive.
10197 @deffn {Scheme Variable} openssh-service-type
10198 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
10199 shell daemon, @command{sshd}. Its value must be an
10200 @code{openssh-configuration} record as in this example:
10203 (service openssh-service-type
10204 (openssh-configuration
10205 (x11-forwarding? #t)
10206 (permit-root-login 'without-password)
10208 `(("alice" ,(local-file "alice.pub"))
10209 ("bob" ,(local-file "bob.pub"))))))
10212 See below for details about @code{openssh-configuration}.
10214 This service can be extended with extra authorized keys, as in this
10218 (service-extension openssh-service-type
10219 (const `(("charlie"
10220 ,(local-file "charlie.pub")))))
10224 @deftp {Data Type} openssh-configuration
10225 This is the configuration record for OpenSSH's @command{sshd}.
10228 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
10229 Name of the file where @command{sshd} writes its PID.
10231 @item @code{port-number} (default: @code{22})
10232 TCP port on which @command{sshd} listens for incoming connections.
10234 @item @code{permit-root-login} (default: @code{#f})
10235 This field determines whether and when to allow logins as root. If
10236 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
10237 If it's the symbol @code{'without-password}, then root logins are
10238 permitted but not with password-based authentication.
10240 @item @code{allow-empty-passwords?} (default: @code{#f})
10241 When true, users with empty passwords may log in. When false, they may
10244 @item @code{password-authentication?} (default: @code{#t})
10245 When true, users may log in with their password. When false, they have
10246 other authentication methods.
10248 @item @code{public-key-authentication?} (default: @code{#t})
10249 When true, users may log in using public key authentication. When
10250 false, users have to use other authentication method.
10252 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
10253 This is used only by protocol version 2.
10255 @item @code{x11-forwarding?} (default: @code{#f})
10256 When true, forwarding of X11 graphical client connections is
10257 enabled---in other words, @command{ssh} options @option{-X} and
10258 @option{-Y} will work.
10260 @item @code{challenge-response-authentication?} (default: @code{#f})
10261 Specifies whether challenge response authentication is allowed (e.g. via
10264 @item @code{use-pam?} (default: @code{#t})
10265 Enables the Pluggable Authentication Module interface. If set to
10266 @code{#t}, this will enable PAM authentication using
10267 @code{challenge-response-authentication?} and
10268 @code{password-authentication?}, in addition to PAM account and session
10269 module processing for all authentication types.
10271 Because PAM challenge response authentication usually serves an
10272 equivalent role to password authentication, you should disable either
10273 @code{challenge-response-authentication?} or
10274 @code{password-authentication?}.
10276 @item @code{print-last-log?} (default: @code{#t})
10277 Specifies whether @command{sshd} should print the date and time of the
10278 last user login when a user logs in interactively.
10280 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
10281 Configures external subsystems (e.g. file transfer daemon).
10283 This is a list of two-element lists, each of which containing the
10284 subsystem name and a command (with optional arguments) to execute upon
10287 The command @command{internal-sftp} implements an in-process SFTP
10288 server. Alternately, one can specify the @command{sftp-server} command:
10290 (service openssh-service-type
10291 (openssh-configuration
10293 `(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
10296 @item @code{authorized-keys} (default: @code{'()})
10297 @cindex authorized keys, SSH
10298 @cindex SSH authorized keys
10299 This is the list of authorized keys. Each element of the list is a user
10300 name followed by one or more file-like objects that represent SSH public
10304 (openssh-configuration
10306 `(("rekado" ,(local-file "rekado.pub"))
10307 ("chris" ,(local-file "chris.pub"))
10308 ("root" ,(local-file "rekado.pub") ,(local-file "chris.pub")))))
10312 registers the specified public keys for user accounts @code{rekado},
10313 @code{chris}, and @code{root}.
10315 Additional authorized keys can be specified @i{via}
10316 @code{service-extension}.
10318 Note that this does @emph{not} interfere with the use of
10319 @file{~/.ssh/authorized_keys}.
10323 @deffn {Scheme Procedure} dropbear-service [@var{config}]
10324 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
10325 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
10328 For example, to specify a Dropbear service listening on port 1234, add
10329 this call to the operating system's @code{services} field:
10332 (dropbear-service (dropbear-configuration
10333 (port-number 1234)))
10337 @deftp {Data Type} dropbear-configuration
10338 This data type represents the configuration of a Dropbear SSH daemon.
10341 @item @code{dropbear} (default: @var{dropbear})
10342 The Dropbear package to use.
10344 @item @code{port-number} (default: 22)
10345 The TCP port where the daemon waits for incoming connections.
10347 @item @code{syslog-output?} (default: @code{#t})
10348 Whether to enable syslog output.
10350 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
10351 File name of the daemon's PID file.
10353 @item @code{root-login?} (default: @code{#f})
10354 Whether to allow @code{root} logins.
10356 @item @code{allow-empty-passwords?} (default: @code{#f})
10357 Whether to allow empty passwords.
10359 @item @code{password-authentication?} (default: @code{#t})
10360 Whether to enable password-based authentication.
10364 @defvr {Scheme Variable} %facebook-host-aliases
10365 This variable contains a string for use in @file{/etc/hosts}
10366 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
10367 line contains a entry that maps a known server name of the Facebook
10368 on-line service---e.g., @code{www.facebook.com}---to the local
10369 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
10371 This variable is typically used in the @code{hosts-file} field of an
10372 @code{operating-system} declaration (@pxref{operating-system Reference,
10373 @file{/etc/hosts}}):
10376 (use-modules (gnu) (guix))
10379 (host-name "mymachine")
10382 ;; Create a /etc/hosts file with aliases for "localhost"
10383 ;; and "mymachine", as well as for Facebook servers.
10384 (plain-file "hosts"
10385 (string-append (local-host-aliases host-name)
10386 %facebook-host-aliases))))
10389 This mechanism can prevent programs running locally, such as Web
10390 browsers, from accessing Facebook.
10393 The @code{(gnu services avahi)} provides the following definition.
10395 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
10396 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
10397 [#:ipv6? #t] [#:wide-area? #f] @
10398 [#:domains-to-browse '()] [#:debug? #f]
10399 Return a service that runs @command{avahi-daemon}, a system-wide
10400 mDNS/DNS-SD responder that allows for service discovery and
10401 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
10402 extends the name service cache daemon (nscd) so that it can resolve
10403 @code{.local} host names using
10404 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
10405 add the @var{avahi} package to the system profile so that commands such as
10406 @command{avahi-browse} are directly usable.
10408 If @var{host-name} is different from @code{#f}, use that as the host name to
10409 publish for this machine; otherwise, use the machine's actual host name.
10411 When @var{publish?} is true, publishing of host names and services is allowed;
10412 in particular, avahi-daemon will publish the machine's host name and IP
10413 address via mDNS on the local network.
10415 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
10417 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
10421 @deffn {Scheme Variable} openvswitch-service-type
10422 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
10423 service, whose value should be an @code{openvswitch-configuration}
10427 @deftp {Data Type} openvswitch-configuration
10428 Data type representing the configuration of Open vSwitch, a multilayer
10429 virtual switch which is designed to enable massive network automation
10430 through programmatic extension.
10433 @item @code{package} (default: @var{openvswitch})
10434 Package object of the Open vSwitch.
10440 @subsubsection X Window
10443 @cindex X Window System
10444 Support for the X Window graphical display system---specifically
10445 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
10446 there is no @code{xorg-service} procedure. Instead, the X server is
10447 started by the @dfn{login manager}, currently SLiM.
10449 @deftp {Data Type} sddm-configuration
10450 This is the data type representing the sddm service configuration.
10453 @item @code{display-server} (default: "x11")
10454 Select display server to use for the greeter. Valid values are "x11"
10457 @item @code{numlock} (default: "on")
10458 Valid values are "on", "off" or "none".
10460 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
10461 Command to run when halting.
10463 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
10464 Command to run when rebooting.
10466 @item @code{theme} (default "maldives")
10467 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
10469 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
10470 Directory to look for themes.
10472 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
10473 Directory to look for faces.
10475 @item @code{default-path} (default "/run/current-system/profile/bin")
10476 Default PATH to use.
10478 @item @code{minimum-uid} (default 1000)
10479 Minimum UID to display in SDDM.
10481 @item @code{maximum-uid} (default 2000)
10482 Maximum UID to display in SDDM
10484 @item @code{remember-last-user?} (default #t)
10485 Remember last user.
10487 @item @code{remember-last-session?} (default #t)
10488 Remember last session.
10490 @item @code{hide-users} (default "")
10491 Usernames to hide from SDDM greeter.
10493 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10494 Users with shells listed will be hidden from the SDDM greeter.
10496 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10497 Script to run before starting a wayland session.
10499 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10500 Directory to look for desktop files starting wayland sessions.
10502 @item @code{xorg-server-path} (default @code{xorg-start-command})
10503 Path to xorg-server.
10505 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10508 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
10511 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
10512 Script to run after starting xorg-server.
10514 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
10515 Script to run before stopping xorg-server.
10517 @item @code{xsession-command} (default: @code{xinitr })
10518 Script to run before starting a X session.
10520 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
10521 Directory to look for desktop files starting X sessions.
10523 @item @code{minimum-vt} (default: 7)
10526 @item @code{xserver-arguments} (default "-nolisten tcp")
10527 Arguments to pass to xorg-server.
10529 @item @code{auto-login-user} (default "")
10530 User to use for auto-login.
10532 @item @code{auto-login-session} (default "")
10533 Desktop file to use for auto-login.
10535 @item @code{relogin?} (default #f)
10536 Relogin after logout.
10541 @cindex login manager
10542 @deffn {Scheme Procedure} sddm-service config
10543 Return a service that spawns the SDDM graphical login manager for config of
10544 type @code{<sddm-configuration>}.
10547 (sddm-service (sddm-configuration
10548 (auto-login-user "Alice")
10549 (auto-login-session "xfce.desktop")))
10553 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10554 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10555 [#:theme @var{%default-slim-theme}] @
10556 [#:theme-name @var{%default-slim-theme-name}]
10557 Return a service that spawns the SLiM graphical login manager, which in
10558 turn starts the X display server with @var{startx}, a command as returned by
10559 @code{xorg-start-command}.
10563 SLiM automatically looks for session types described by the @file{.desktop}
10564 files in @file{/run/current-system/profile/share/xsessions} and allows users
10565 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10566 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10567 adding them to the system-wide set of packages automatically makes them
10568 available at the log-in screen.
10570 In addition, @file{~/.xsession} files are honored. When available,
10571 @file{~/.xsession} must be an executable that starts a window manager
10572 and/or other X clients.
10574 When @var{allow-empty-passwords?} is true, allow logins with an empty
10575 password. When @var{auto-login?} is true, log in automatically as
10576 @var{default-user}.
10578 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10579 @var{theme} must be a gexp denoting the name of a directory containing the
10580 theme to use. In that case, @var{theme-name} specifies the name of the
10584 @defvr {Scheme Variable} %default-theme
10585 @defvrx {Scheme Variable} %default-theme-name
10586 The G-Expression denoting the default SLiM theme and its name.
10589 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10590 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10591 Return a derivation that builds a @var{guile} script to start the X server
10592 from @var{xorg-server}. @var{configuration-file} is the server configuration
10593 file or a derivation that builds it; when omitted, the result of
10594 @code{xorg-configuration-file} is used.
10596 Usually the X server is started by a login manager.
10599 @deffn {Scheme Procedure} xorg-configuration-file @
10600 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10601 Return a configuration file for the Xorg server containing search paths for
10602 all the common drivers.
10604 @var{drivers} must be either the empty list, in which case Xorg chooses a
10605 graphics driver automatically, or a list of driver names that will be tried in
10606 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10608 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10609 appropriate screen resolution; otherwise, it must be a list of
10610 resolutions---e.g., @code{((1024 768) (640 480))}.
10612 Last, @var{extra-config} is a list of strings or objects appended to the
10613 @code{text-file*} argument list. It is used to pass extra text to be added
10614 verbatim to the configuration file.
10617 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10618 Add @var{package}, a package for a screen-locker or screen-saver whose
10619 command is @var{program}, to the set of setuid programs and add a PAM entry
10620 for it. For example:
10623 (screen-locker-service xlockmore "xlock")
10626 makes the good ol' XlockMore usable.
10630 @node Printing Services
10631 @subsubsection Printing Services
10633 @cindex printer support with CUPS
10634 The @code{(gnu services cups)} module provides a Guix service definition
10635 for the CUPS printing service. To add printer support to a GuixSD
10636 system, add a @code{cups-service} to the operating system definition:
10638 @deffn {Scheme Variable} cups-service-type
10639 The service type for the CUPS print server. Its value should be a valid
10640 CUPS configuration (see below). To use the default settings, simply
10643 (service cups-service-type)
10647 The CUPS configuration controls the basic things about your CUPS
10648 installation: what interfaces it listens on, what to do if a print job
10649 fails, how much logging to do, and so on. To actually add a printer,
10650 you have to visit the @url{http://localhost:631} URL, or use a tool such
10651 as GNOME's printer configuration services. By default, configuring a
10652 CUPS service will generate a self-signed certificate if needed, for
10653 secure connections to the print server.
10655 Suppose you want to enable the Web interface of CUPS and also add
10656 support for HP printers @i{via} the @code{hplip} package. You can do
10657 that directly, like this (you need to use the @code{(gnu packages cups)}
10661 (service cups-service-type
10662 (cups-configuration
10663 (web-interface? #t)
10665 (list cups-filters hplip))))
10668 The available configuration parameters follow. Each parameter
10669 definition is preceded by its type; for example, @samp{string-list foo}
10670 indicates that the @code{foo} parameter should be specified as a list of
10671 strings. There is also a way to specify the configuration as a string,
10672 if you have an old @code{cupsd.conf} file that you want to port over
10673 from some other system; see the end for more details.
10675 @c The following documentation was initially generated by
10676 @c (generate-documentation) in (gnu services cups). Manually maintained
10677 @c documentation is better, so we shouldn't hesitate to edit below as
10678 @c needed. However if the change you want to make to this documentation
10679 @c can be done in an automated way, it's probably easier to change
10680 @c (generate-documentation) than to make it below and have to deal with
10681 @c the churn as CUPS updates.
10684 Available @code{cups-configuration} fields are:
10686 @deftypevr {@code{cups-configuration} parameter} package cups
10690 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10691 Drivers and other extensions to the CUPS package.
10694 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10695 Configuration of where to write logs, what directories to use for print
10696 spools, and related privileged configuration parameters.
10698 Available @code{files-configuration} fields are:
10700 @deftypevr {@code{files-configuration} parameter} log-location access-log
10701 Defines the access log filename. Specifying a blank filename disables
10702 access log generation. The value @code{stderr} causes log entries to be
10703 sent to the standard error file when the scheduler is running in the
10704 foreground, or to the system log daemon when run in the background. The
10705 value @code{syslog} causes log entries to be sent to the system log
10706 daemon. The server name may be included in filenames using the string
10707 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10709 Defaults to @samp{"/var/log/cups/access_log"}.
10712 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10713 Where CUPS should cache data.
10715 Defaults to @samp{"/var/cache/cups"}.
10718 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10719 Specifies the permissions for all configuration files that the scheduler
10722 Note that the permissions for the printers.conf file are currently
10723 masked to only allow access from the scheduler user (typically root).
10724 This is done because printer device URIs sometimes contain sensitive
10725 authentication information that should not be generally known on the
10726 system. There is no way to disable this security feature.
10728 Defaults to @samp{"0640"}.
10731 @deftypevr {@code{files-configuration} parameter} log-location error-log
10732 Defines the error log filename. Specifying a blank filename disables
10733 access log generation. The value @code{stderr} causes log entries to be
10734 sent to the standard error file when the scheduler is running in the
10735 foreground, or to the system log daemon when run in the background. The
10736 value @code{syslog} causes log entries to be sent to the system log
10737 daemon. The server name may be included in filenames using the string
10738 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10740 Defaults to @samp{"/var/log/cups/error_log"}.
10743 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10744 Specifies which errors are fatal, causing the scheduler to exit. The
10749 No errors are fatal.
10752 All of the errors below are fatal.
10755 Browsing initialization errors are fatal, for example failed connections
10756 to the DNS-SD daemon.
10759 Configuration file syntax errors are fatal.
10762 Listen or Port errors are fatal, except for IPv6 failures on the
10763 loopback or @code{any} addresses.
10766 Log file creation or write errors are fatal.
10769 Bad startup file permissions are fatal, for example shared TLS
10770 certificate and key files with world-read permissions.
10773 Defaults to @samp{"all -browse"}.
10776 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10777 Specifies whether the file pseudo-device can be used for new printer
10778 queues. The URI @uref{file:///dev/null} is always allowed.
10780 Defaults to @samp{#f}.
10783 @deftypevr {@code{files-configuration} parameter} string group
10784 Specifies the group name or ID that will be used when executing external
10787 Defaults to @samp{"lp"}.
10790 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10791 Specifies the permissions for all log files that the scheduler writes.
10793 Defaults to @samp{"0644"}.
10796 @deftypevr {@code{files-configuration} parameter} log-location page-log
10797 Defines the page log filename. Specifying a blank filename disables
10798 access log generation. The value @code{stderr} causes log entries to be
10799 sent to the standard error file when the scheduler is running in the
10800 foreground, or to the system log daemon when run in the background. The
10801 value @code{syslog} causes log entries to be sent to the system log
10802 daemon. The server name may be included in filenames using the string
10803 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10805 Defaults to @samp{"/var/log/cups/page_log"}.
10808 @deftypevr {@code{files-configuration} parameter} string remote-root
10809 Specifies the username that is associated with unauthenticated accesses
10810 by clients claiming to be the root user. The default is @code{remroot}.
10812 Defaults to @samp{"remroot"}.
10815 @deftypevr {@code{files-configuration} parameter} file-name request-root
10816 Specifies the directory that contains print jobs and other HTTP request
10819 Defaults to @samp{"/var/spool/cups"}.
10822 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10823 Specifies the level of security sandboxing that is applied to print
10824 filters, backends, and other child processes of the scheduler; either
10825 @code{relaxed} or @code{strict}. This directive is currently only
10826 used/supported on macOS.
10828 Defaults to @samp{strict}.
10831 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10832 Specifies the location of TLS certificates and private keys. CUPS will
10833 look for public and private keys in this directory: a @code{.crt} files
10834 for PEM-encoded certificates and corresponding @code{.key} files for
10835 PEM-encoded private keys.
10837 Defaults to @samp{"/etc/cups/ssl"}.
10840 @deftypevr {@code{files-configuration} parameter} file-name server-root
10841 Specifies the directory containing the server configuration files.
10843 Defaults to @samp{"/etc/cups"}.
10846 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10847 Specifies whether the scheduler calls fsync(2) after writing
10848 configuration or state files.
10850 Defaults to @samp{#f}.
10853 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10854 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10857 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10858 Specifies the directory where temporary files are stored.
10860 Defaults to @samp{"/var/spool/cups/tmp"}.
10863 @deftypevr {@code{files-configuration} parameter} string user
10864 Specifies the user name or ID that is used when running external
10867 Defaults to @samp{"lp"}.
10871 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10872 Specifies the logging level for the AccessLog file. The @code{config}
10873 level logs when printers and classes are added, deleted, or modified and
10874 when configuration files are accessed or updated. The @code{actions}
10875 level logs when print jobs are submitted, held, released, modified, or
10876 canceled, and any of the conditions for @code{config}. The @code{all}
10877 level logs all requests.
10879 Defaults to @samp{actions}.
10882 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10883 Specifies whether to purge job history data automatically when it is no
10884 longer required for quotas.
10886 Defaults to @samp{#f}.
10889 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10890 Specifies which protocols to use for local printer sharing.
10892 Defaults to @samp{dnssd}.
10895 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10896 Specifies whether the CUPS web interface is advertised.
10898 Defaults to @samp{#f}.
10901 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10902 Specifies whether shared printers are advertised.
10904 Defaults to @samp{#f}.
10907 @deftypevr {@code{cups-configuration} parameter} string classification
10908 Specifies the security classification of the server. Any valid banner
10909 name can be used, including "classified", "confidential", "secret",
10910 "topsecret", and "unclassified", or the banner can be omitted to disable
10911 secure printing functions.
10913 Defaults to @samp{""}.
10916 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
10917 Specifies whether users may override the classification (cover page) of
10918 individual print jobs using the @code{job-sheets} option.
10920 Defaults to @samp{#f}.
10923 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
10924 Specifies the default type of authentication to use.
10926 Defaults to @samp{Basic}.
10929 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
10930 Specifies whether encryption will be used for authenticated requests.
10932 Defaults to @samp{Required}.
10935 @deftypevr {@code{cups-configuration} parameter} string default-language
10936 Specifies the default language to use for text and web content.
10938 Defaults to @samp{"en"}.
10941 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
10942 Specifies the default paper size for new print queues. @samp{"Auto"}
10943 uses a locale-specific default, while @samp{"None"} specifies there is
10944 no default paper size. Specific size names are typically
10945 @samp{"Letter"} or @samp{"A4"}.
10947 Defaults to @samp{"Auto"}.
10950 @deftypevr {@code{cups-configuration} parameter} string default-policy
10951 Specifies the default access policy to use.
10953 Defaults to @samp{"default"}.
10956 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
10957 Specifies whether local printers are shared by default.
10959 Defaults to @samp{#t}.
10962 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
10963 Specifies the delay for updating of configuration and state files, in
10964 seconds. A value of 0 causes the update to happen as soon as possible,
10965 typically within a few milliseconds.
10967 Defaults to @samp{30}.
10970 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
10971 Specifies what to do when an error occurs. Possible values are
10972 @code{abort-job}, which will discard the failed print job;
10973 @code{retry-job}, which will retry the job at a later time;
10974 @code{retry-this-job}, which retries the failed job immediately; and
10975 @code{stop-printer}, which stops the printer.
10977 Defaults to @samp{stop-printer}.
10980 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
10981 Specifies the maximum cost of filters that are run concurrently, which
10982 can be used to minimize disk, memory, and CPU resource problems. A
10983 limit of 0 disables filter limiting. An average print to a
10984 non-PostScript printer needs a filter limit of about 200. A PostScript
10985 printer needs about half that (100). Setting the limit below these
10986 thresholds will effectively limit the scheduler to printing a single job
10989 Defaults to @samp{0}.
10992 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
10993 Specifies the scheduling priority of filters that are run to print a
10994 job. The nice value ranges from 0, the highest priority, to 19, the
10997 Defaults to @samp{0}.
11000 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
11001 Specifies whether to do reverse lookups on connecting clients. The
11002 @code{double} setting causes @code{cupsd} to verify that the hostname
11003 resolved from the address matches one of the addresses returned for that
11004 hostname. Double lookups also prevent clients with unregistered
11005 addresses from connecting to your server. Only set this option to
11006 @code{#t} or @code{double} if absolutely required.
11008 Defaults to @samp{#f}.
11011 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
11012 Specifies the number of seconds to wait before killing the filters and
11013 backend associated with a canceled or held job.
11015 Defaults to @samp{30}.
11018 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
11019 Specifies the interval between retries of jobs in seconds. This is
11020 typically used for fax queues but can also be used with normal print
11021 queues whose error policy is @code{retry-job} or
11022 @code{retry-current-job}.
11024 Defaults to @samp{30}.
11027 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
11028 Specifies the number of retries that are done for jobs. This is
11029 typically used for fax queues but can also be used with normal print
11030 queues whose error policy is @code{retry-job} or
11031 @code{retry-current-job}.
11033 Defaults to @samp{5}.
11036 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
11037 Specifies whether to support HTTP keep-alive connections.
11039 Defaults to @samp{#t}.
11042 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
11043 Specifies how long an idle client connection remains open, in seconds.
11045 Defaults to @samp{30}.
11048 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
11049 Specifies the maximum size of print files, IPP requests, and HTML form
11050 data. A limit of 0 disables the limit check.
11052 Defaults to @samp{0}.
11055 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
11056 Listens on the specified interfaces for connections. Valid values are
11057 of the form @var{address}:@var{port}, where @var{address} is either an
11058 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
11059 indicate all addresses. Values can also be file names of local UNIX
11060 domain sockets. The Listen directive is similar to the Port directive
11061 but allows you to restrict access to specific interfaces or networks.
11064 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
11065 Specifies the number of pending connections that will be allowed. This
11066 normally only affects very busy servers that have reached the MaxClients
11067 limit, but can also be triggered by large numbers of simultaneous
11068 connections. When the limit is reached, the operating system will
11069 refuse additional connections until the scheduler can accept the pending
11072 Defaults to @samp{128}.
11075 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
11076 Specifies a set of additional access controls.
11078 Available @code{location-access-controls} fields are:
11080 @deftypevr {@code{location-access-controls} parameter} file-name path
11081 Specifies the URI path to which the access control applies.
11084 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
11085 Access controls for all access to this path, in the same format as the
11086 @code{access-controls} of @code{operation-access-control}.
11088 Defaults to @samp{()}.
11091 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
11092 Access controls for method-specific access to this path.
11094 Defaults to @samp{()}.
11096 Available @code{method-access-controls} fields are:
11098 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
11099 If @code{#t}, apply access controls to all methods except the listed
11100 methods. Otherwise apply to only the listed methods.
11102 Defaults to @samp{#f}.
11105 @deftypevr {@code{method-access-controls} parameter} method-list methods
11106 Methods to which this access control applies.
11108 Defaults to @samp{()}.
11111 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
11112 Access control directives, as a list of strings. Each string should be
11113 one directive, such as "Order allow,deny".
11115 Defaults to @samp{()}.
11120 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
11121 Specifies the number of debugging messages that are retained for logging
11122 if an error occurs in a print job. Debug messages are logged regardless
11123 of the LogLevel setting.
11125 Defaults to @samp{100}.
11128 @deftypevr {@code{cups-configuration} parameter} log-level log-level
11129 Specifies the level of logging for the ErrorLog file. The value
11130 @code{none} stops all logging while @code{debug2} logs everything.
11132 Defaults to @samp{info}.
11135 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
11136 Specifies the format of the date and time in the log files. The value
11137 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
11139 Defaults to @samp{standard}.
11142 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
11143 Specifies the maximum number of simultaneous clients that are allowed by
11146 Defaults to @samp{100}.
11149 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
11150 Specifies the maximum number of simultaneous clients that are allowed
11151 from a single address.
11153 Defaults to @samp{100}.
11156 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
11157 Specifies the maximum number of copies that a user can print of each
11160 Defaults to @samp{9999}.
11163 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
11164 Specifies the maximum time a job may remain in the @code{indefinite}
11165 hold state before it is canceled. A value of 0 disables cancellation of
11168 Defaults to @samp{0}.
11171 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
11172 Specifies the maximum number of simultaneous jobs that are allowed. Set
11173 to 0 to allow an unlimited number of jobs.
11175 Defaults to @samp{500}.
11178 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
11179 Specifies the maximum number of simultaneous jobs that are allowed per
11180 printer. A value of 0 allows up to MaxJobs jobs per printer.
11182 Defaults to @samp{0}.
11185 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
11186 Specifies the maximum number of simultaneous jobs that are allowed per
11187 user. A value of 0 allows up to MaxJobs jobs per user.
11189 Defaults to @samp{0}.
11192 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
11193 Specifies the maximum time a job may take to print before it is
11194 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
11196 Defaults to @samp{10800}.
11199 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
11200 Specifies the maximum size of the log files before they are rotated, in
11201 bytes. The value 0 disables log rotation.
11203 Defaults to @samp{1048576}.
11206 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
11207 Specifies the maximum amount of time to allow between files in a
11208 multiple file print job, in seconds.
11210 Defaults to @samp{300}.
11213 @deftypevr {@code{cups-configuration} parameter} string page-log-format
11214 Specifies the format of PageLog lines. Sequences beginning with percent
11215 (@samp{%}) characters are replaced with the corresponding information,
11216 while all other characters are copied literally. The following percent
11217 sequences are recognized:
11221 insert a single percent character
11224 insert the value of the specified IPP attribute
11227 insert the number of copies for the current page
11230 insert the current page number
11233 insert the current date and time in common log format
11239 insert the printer name
11242 insert the username
11245 A value of the empty string disables page logging. The string @code{%p
11246 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
11247 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
11250 Defaults to @samp{""}.
11253 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
11254 Passes the specified environment variable(s) to child processes; a list
11257 Defaults to @samp{()}.
11260 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
11261 Specifies named access control policies.
11263 Available @code{policy-configuration} fields are:
11265 @deftypevr {@code{policy-configuration} parameter} string name
11266 Name of the policy.
11269 @deftypevr {@code{policy-configuration} parameter} string job-private-access
11270 Specifies an access list for a job's private values. @code{@@ACL} maps
11271 to the printer's requesting-user-name-allowed or
11272 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11273 owner. @code{@@SYSTEM} maps to the groups listed for the
11274 @code{system-group} field of the @code{files-config} configuration,
11275 which is reified into the @code{cups-files.conf(5)} file. Other
11276 possible elements of the access list include specific user names, and
11277 @code{@@@var{group}} to indicate members of a specific group. The
11278 access list may also be simply @code{all} or @code{default}.
11280 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11283 @deftypevr {@code{policy-configuration} parameter} string job-private-values
11284 Specifies the list of job values to make private, or @code{all},
11285 @code{default}, or @code{none}.
11287 Defaults to @samp{"job-name job-originating-host-name
11288 job-originating-user-name phone"}.
11291 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
11292 Specifies an access list for a subscription's private values.
11293 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
11294 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11295 owner. @code{@@SYSTEM} maps to the groups listed for the
11296 @code{system-group} field of the @code{files-config} configuration,
11297 which is reified into the @code{cups-files.conf(5)} file. Other
11298 possible elements of the access list include specific user names, and
11299 @code{@@@var{group}} to indicate members of a specific group. The
11300 access list may also be simply @code{all} or @code{default}.
11302 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11305 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
11306 Specifies the list of job values to make private, or @code{all},
11307 @code{default}, or @code{none}.
11309 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
11310 notify-subscriber-user-name notify-user-data"}.
11313 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
11314 Access control by IPP operation.
11316 Defaults to @samp{()}.
11320 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
11321 Specifies whether job files (documents) are preserved after a job is
11322 printed. If a numeric value is specified, job files are preserved for
11323 the indicated number of seconds after printing. Otherwise a boolean
11324 value applies indefinitely.
11326 Defaults to @samp{86400}.
11329 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
11330 Specifies whether the job history is preserved after a job is printed.
11331 If a numeric value is specified, the job history is preserved for the
11332 indicated number of seconds after printing. If @code{#t}, the job
11333 history is preserved until the MaxJobs limit is reached.
11335 Defaults to @samp{#t}.
11338 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
11339 Specifies the amount of time to wait for job completion before
11340 restarting the scheduler.
11342 Defaults to @samp{30}.
11345 @deftypevr {@code{cups-configuration} parameter} string rip-cache
11346 Specifies the maximum amount of memory to use when converting documents
11347 into bitmaps for a printer.
11349 Defaults to @samp{"128m"}.
11352 @deftypevr {@code{cups-configuration} parameter} string server-admin
11353 Specifies the email address of the server administrator.
11355 Defaults to @samp{"root@@localhost.localdomain"}.
11358 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
11359 The ServerAlias directive is used for HTTP Host header validation when
11360 clients connect to the scheduler from external interfaces. Using the
11361 special name @code{*} can expose your system to known browser-based DNS
11362 rebinding attacks, even when accessing sites through a firewall. If the
11363 auto-discovery of alternate names does not work, we recommend listing
11364 each alternate name with a ServerAlias directive instead of using
11367 Defaults to @samp{*}.
11370 @deftypevr {@code{cups-configuration} parameter} string server-name
11371 Specifies the fully-qualified host name of the server.
11373 Defaults to @samp{"localhost"}.
11376 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
11377 Specifies what information is included in the Server header of HTTP
11378 responses. @code{None} disables the Server header. @code{ProductOnly}
11379 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
11380 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
11381 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
11382 the output of the @code{uname} command. @code{Full} reports @code{CUPS
11383 2.0.0 (@var{uname}) IPP/2.0}.
11385 Defaults to @samp{Minimal}.
11388 @deftypevr {@code{cups-configuration} parameter} string set-env
11389 Set the specified environment variable to be passed to child processes.
11391 Defaults to @samp{"variable value"}.
11394 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
11395 Listens on the specified interfaces for encrypted connections. Valid
11396 values are of the form @var{address}:@var{port}, where @var{address} is
11397 either an IPv6 address enclosed in brackets, an IPv4 address, or
11398 @code{*} to indicate all addresses.
11400 Defaults to @samp{()}.
11403 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
11404 Sets encryption options. By default, CUPS only supports encryption
11405 using TLS v1.0 or higher using known secure cipher suites. The
11406 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
11407 required for some older clients that do not implement newer ones. The
11408 @code{AllowSSL3} option enables SSL v3.0, which is required for some
11409 older clients that do not support TLS v1.0.
11411 Defaults to @samp{()}.
11414 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
11415 Specifies whether the scheduler requires clients to strictly adhere to
11416 the IPP specifications.
11418 Defaults to @samp{#f}.
11421 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
11422 Specifies the HTTP request timeout, in seconds.
11424 Defaults to @samp{300}.
11428 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
11429 Specifies whether the web interface is enabled.
11431 Defaults to @samp{#f}.
11434 At this point you're probably thinking ``oh dear, Guix manual, I like
11435 you but you can stop already with the configuration options''. Indeed.
11436 However, one more point: it could be that you have an existing
11437 @code{cupsd.conf} that you want to use. In that case, you can pass an
11438 @code{opaque-cups-configuration} as the configuration of a
11439 @code{cups-service-type}.
11441 Available @code{opaque-cups-configuration} fields are:
11443 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
11447 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
11448 The contents of the @code{cupsd.conf}, as a string.
11451 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
11452 The contents of the @code{cups-files.conf} file, as a string.
11455 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
11456 strings of the same name, you could instantiate a CUPS service like
11460 (service cups-service-type
11461 (opaque-cups-configuration
11462 (cupsd.conf cupsd.conf)
11463 (cups-files.conf cups-files.conf)))
11467 @node Desktop Services
11468 @subsubsection Desktop Services
11470 The @code{(gnu services desktop)} module provides services that are
11471 usually useful in the context of a ``desktop'' setup---that is, on a
11472 machine running a graphical display server, possibly with graphical user
11473 interfaces, etc. It also defines services that provide specific desktop
11474 environments like GNOME and XFCE.
11476 To simplify things, the module defines a variable containing the set of
11477 services that users typically expect on a machine with a graphical
11478 environment and networking:
11480 @defvr {Scheme Variable} %desktop-services
11481 This is a list of services that builds upon @var{%base-services} and
11482 adds or adjusts services for a typical ``desktop'' setup.
11484 In particular, it adds a graphical login manager (@pxref{X Window,
11485 @code{slim-service}}), screen lockers,
11486 a network management tool (@pxref{Networking
11487 Services, @code{wicd-service}}), energy and color management services,
11488 the @code{elogind} login and seat manager, the Polkit privilege service,
11489 the GeoClue location service, an NTP client (@pxref{Networking
11490 Services}), the Avahi daemon, and has the name service switch service
11491 configured to be able to use @code{nss-mdns} (@pxref{Name Service
11495 The @var{%desktop-services} variable can be used as the @code{services}
11496 field of an @code{operating-system} declaration (@pxref{operating-system
11497 Reference, @code{services}}).
11499 Additionally, the @code{gnome-desktop-service} and
11500 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11501 system. To ``add GNOME'' means that system-level services like the
11502 backlight adjustment helpers and the power management utilities are
11503 added to the system, extending @code{polkit} and @code{dbus}
11504 appropriately, allowing GNOME to operate with elevated privileges on a
11505 limited number of special-purpose system interfaces. Additionally,
11506 adding a service made by @code{gnome-desktop-service} adds the GNOME
11507 metapackage to the system profile. Likewise, adding the XFCE service
11508 not only adds the @code{xfce} metapackage to the system profile, but it
11509 also gives the Thunar file manager the ability to open a ``root-mode''
11510 file management window, if the user authenticates using the
11511 administrator's password via the standard polkit graphical interface.
11513 @deffn {Scheme Procedure} gnome-desktop-service
11514 Return a service that adds the @code{gnome} package to the system
11515 profile, and extends polkit with the actions from
11516 @code{gnome-settings-daemon}.
11519 @deffn {Scheme Procedure} xfce-desktop-service
11520 Return a service that adds the @code{xfce} package to the system profile,
11521 and extends polkit with the ability for @code{thunar} to manipulate the
11522 file system as root from within a user session, after the user has
11523 authenticated with the administrator's password.
11526 Because the GNOME and XFCE desktop services pull in so many packages,
11527 the default @code{%desktop-services} variable doesn't include either of
11528 them by default. To add GNOME or XFCE, just @code{cons} them onto
11529 @code{%desktop-services} in the @code{services} field of your
11530 @code{operating-system}:
11533 (use-modules (gnu))
11534 (use-service-modules desktop)
11537 ;; cons* adds items to the list given as its last argument.
11538 (services (cons* (gnome-desktop-service)
11539 (xfce-desktop-service)
11540 %desktop-services))
11544 These desktop environments will then be available as options in the
11545 graphical login window.
11547 The actual service definitions included in @code{%desktop-services} and
11548 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
11549 are described below.
11551 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
11552 Return a service that runs the ``system bus'', using @var{dbus}, with
11553 support for @var{services}.
11555 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11556 facility. Its system bus is used to allow system services to communicate
11557 and to be notified of system-wide events.
11559 @var{services} must be a list of packages that provide an
11560 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11561 and policy files. For example, to allow avahi-daemon to use the system bus,
11562 @var{services} must be equal to @code{(list avahi)}.
11565 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11566 Return a service that runs the @code{elogind} login and
11567 seat management daemon. @uref{https://github.com/andywingo/elogind,
11568 Elogind} exposes a D-Bus interface that can be used to know which users
11569 are logged in, know what kind of sessions they have open, suspend the
11570 system, inhibit system suspend, reboot the system, and other tasks.
11572 Elogind handles most system-level power events for a computer, for
11573 example suspending the system when a lid is closed, or shutting it down
11574 when the power button is pressed.
11576 The @var{config} keyword argument specifies the configuration for
11577 elogind, and should be the result of an @code{(elogind-configuration
11578 (@var{parameter} @var{value})...)} invocation. Available parameters and
11579 their default values are:
11582 @item kill-user-processes?
11584 @item kill-only-users
11586 @item kill-exclude-users
11588 @item inhibit-delay-max-seconds
11590 @item handle-power-key
11592 @item handle-suspend-key
11594 @item handle-hibernate-key
11596 @item handle-lid-switch
11598 @item handle-lid-switch-docked
11600 @item power-key-ignore-inhibited?
11602 @item suspend-key-ignore-inhibited?
11604 @item hibernate-key-ignore-inhibited?
11606 @item lid-switch-ignore-inhibited?
11608 @item holdoff-timeout-seconds
11612 @item idle-action-seconds
11614 @item runtime-directory-size-percent
11616 @item runtime-directory-size
11620 @item suspend-state
11621 @code{("mem" "standby" "freeze")}
11624 @item hibernate-state
11626 @item hibernate-mode
11627 @code{("platform" "shutdown")}
11628 @item hybrid-sleep-state
11630 @item hybrid-sleep-mode
11631 @code{("suspend" "platform" "shutdown")}
11635 @deffn {Scheme Procedure} polkit-service @
11636 [#:polkit @var{polkit}]
11637 Return a service that runs the
11638 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11639 management service}, which allows system administrators to grant access to
11640 privileged operations in a structured way. By querying the Polkit service, a
11641 privileged system component can know when it should grant additional
11642 capabilities to ordinary users. For example, an ordinary user can be granted
11643 the capability to suspend the system if the user is logged in locally.
11646 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11647 [#:watts-up-pro? #f] @
11648 [#:poll-batteries? #t] @
11649 [#:ignore-lid? #f] @
11650 [#:use-percentage-for-policy? #f] @
11651 [#:percentage-low 10] @
11652 [#:percentage-critical 3] @
11653 [#:percentage-action 2] @
11654 [#:time-low 1200] @
11655 [#:time-critical 300] @
11656 [#:time-action 120] @
11657 [#:critical-power-action 'hybrid-sleep]
11658 Return a service that runs @uref{http://upower.freedesktop.org/,
11659 @command{upowerd}}, a system-wide monitor for power consumption and battery
11660 levels, with the given configuration settings. It implements the
11661 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11665 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11666 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11667 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11668 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11669 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11672 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11673 Return a service that runs @command{colord}, a system service with a D-Bus
11674 interface to manage the color profiles of input and output devices such as
11675 screens and scanners. It is notably used by the GNOME Color Manager graphical
11676 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11677 site} for more information.
11680 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11681 Return a configuration allowing an application to access GeoClue
11682 location data. @var{name} is the Desktop ID of the application, without
11683 the @code{.desktop} part. If @var{allowed?} is true, the application
11684 will have access to location information by default. The boolean
11685 @var{system?} value indicates whether an application is a system component
11686 or not. Finally @var{users} is a list of UIDs of all users for which
11687 this application is allowed location info access. An empty users list
11688 means that all users are allowed.
11691 @defvr {Scheme Variable} %standard-geoclue-applications
11692 The standard list of well-known GeoClue application configurations,
11693 granting authority to the GNOME date-and-time utility to ask for the
11694 current location in order to set the time zone, and allowing the
11695 IceCat and Epiphany web browsers to request location information.
11696 IceCat and Epiphany both query the user before allowing a web page to
11697 know the user's location.
11700 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11701 [#:whitelist '()] @
11702 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11703 [#:submit-data? #f]
11704 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11705 [#:submission-nick "geoclue"] @
11706 [#:applications %standard-geoclue-applications]
11707 Return a service that runs the GeoClue location service. This service
11708 provides a D-Bus interface to allow applications to request access to a
11709 user's physical location, and optionally to add information to online
11710 location databases. See
11711 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11712 web site} for more information.
11715 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
11716 Return a service that runs the @command{bluetoothd} daemon, which manages
11717 all the Bluetooth devices and provides a number of D-Bus interfaces.
11719 Users need to be in the @code{lp} group to access the D-Bus service.
11722 @node Database Services
11723 @subsubsection Database Services
11727 The @code{(gnu services databases)} module provides the following services.
11729 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11730 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11731 [#:port 5432] [#:locale ``en_US.utf8'']
11732 Return a service that runs @var{postgresql}, the PostgreSQL database
11735 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11736 creates a database cluster with @var{locale} as the default
11737 locale, stored in @var{data-directory}. It then listens on @var{port}.
11740 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11741 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11744 The optional @var{config} argument specifies the configuration for
11745 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11748 @deftp {Data Type} mysql-configuration
11749 Data type representing the configuration of @var{mysql-service}.
11752 @item @code{mysql} (default: @var{mariadb})
11753 Package object of the MySQL database server, can be either @var{mariadb}
11756 For MySQL, a temporary root password will be displayed at activation time.
11757 For MariaDB, the root password is empty.
11759 @item @code{port} (default: @code{3306})
11760 TCP port on which the database server listens for incoming connections.
11764 @defvr {Scheme Variable} memcached-service-type
11765 This is the service type for the @uref{https://memcached.org/,
11766 Memcached} service, which provides a distributed in memory cache. The
11767 value for the service type is a @code{memcached-configuration} object.
11771 (service memcached-service-type)
11774 @deftp {Data Type} memcached-configuration
11775 Data type representing the configuration of memcached.
11778 @item @code{memcached} (default: @code{memcached})
11779 The Memcached package to use.
11781 @item @code{interfaces} (default: @code{'("0.0.0.0")})
11782 Network interfaces on which to listen.
11784 @item @code{tcp-port} (default: @code{11211})
11785 Port on which to accept connections on,
11787 @item @code{udp-port} (default: @code{11211})
11788 Port on which to accept UDP connections on, a value of 0 will disable
11789 listening on a UDP socket.
11791 @item @code{additional-options} (default: @code{'()})
11792 Additional command line options to pass to @code{memcached}.
11796 @defvr {Scheme Variable} redis-service-type
11797 This is the service type for the @uref{https://redis.io/, Redis}
11798 key/value store, whose value is a @code{redis-configuration} object.
11801 @deftp {Data Type} redis-configuration
11802 Data type representing the configuration of redis.
11805 @item @code{redis} (default: @code{redis})
11806 The Redis package to use.
11808 @item @code{bind} (default: @code{"127.0.0.1"})
11809 Network interface on which to listen.
11811 @item @code{port} (default: @code{6379})
11812 Port on which to accept connections on, a value of 0 will disable
11813 listening on a TCP socket.
11815 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11816 Directory in which to store the database and related files.
11820 @node Mail Services
11821 @subsubsection Mail Services
11825 The @code{(gnu services mail)} module provides Guix service definitions
11826 for email services: IMAP, POP3, and LMTP servers, as well as mail
11827 transport agents (MTAs). Lots of acronyms! These services are detailed
11828 in the subsections below.
11830 @subsubheading Dovecot Service
11832 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11833 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11836 By default, Dovecot does not need much configuration; the default
11837 configuration object created by @code{(dovecot-configuration)} will
11838 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11839 certificate will be generated for TLS-protected connections, though
11840 Dovecot will also listen on cleartext ports by default. There are a
11841 number of options, though, which mail administrators might need to change,
11842 and as is the case with other services, Guix allows the system
11843 administrator to specify these parameters via a uniform Scheme interface.
11845 For example, to specify that mail is located at @code{maildir~/.mail},
11846 one would instantiate the Dovecot service like this:
11849 (dovecot-service #:config
11850 (dovecot-configuration
11851 (mail-location "maildir:~/.mail")))
11854 The available configuration parameters follow. Each parameter
11855 definition is preceded by its type; for example, @samp{string-list foo}
11856 indicates that the @code{foo} parameter should be specified as a list of
11857 strings. There is also a way to specify the configuration as a string,
11858 if you have an old @code{dovecot.conf} file that you want to port over
11859 from some other system; see the end for more details.
11861 @c The following documentation was initially generated by
11862 @c (generate-documentation) in (gnu services mail). Manually maintained
11863 @c documentation is better, so we shouldn't hesitate to edit below as
11864 @c needed. However if the change you want to make to this documentation
11865 @c can be done in an automated way, it's probably easier to change
11866 @c (generate-documentation) than to make it below and have to deal with
11867 @c the churn as dovecot updates.
11869 Available @code{dovecot-configuration} fields are:
11871 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11872 The dovecot package.
11875 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11876 A list of IPs or hosts where to listen for connections. @samp{*}
11877 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11878 interfaces. If you want to specify non-default ports or anything more
11879 complex, customize the address and port fields of the
11880 @samp{inet-listener} of the specific services you are interested in.
11883 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11884 List of protocols we want to serve. Available protocols include
11885 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11887 Available @code{protocol-configuration} fields are:
11889 @deftypevr {@code{protocol-configuration} parameter} string name
11890 The name of the protocol.
11893 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
11894 UNIX socket path to the master authentication server to find users.
11895 This is used by imap (for shared users) and lda.
11896 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11899 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
11900 Space separated list of plugins to load.
11903 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
11904 Maximum number of IMAP connections allowed for a user from each IP
11905 address. NOTE: The username is compared case-sensitively.
11906 Defaults to @samp{10}.
11911 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
11912 List of services to enable. Available services include @samp{imap},
11913 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
11916 Available @code{service-configuration} fields are:
11918 @deftypevr {@code{service-configuration} parameter} string kind
11919 The service kind. Valid values include @code{director},
11920 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
11921 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
11922 @code{tcpwrap}, @code{quota-warning}, or anything else.
11925 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
11926 Listeners for the service. A listener is either a
11927 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
11928 an @code{inet-listener-configuration}.
11929 Defaults to @samp{()}.
11931 Available @code{unix-listener-configuration} fields are:
11933 @deftypevr {@code{unix-listener-configuration} parameter} string path
11934 Path to the file, relative to @code{base-dir} field. This is also used as
11938 @deftypevr {@code{unix-listener-configuration} parameter} string mode
11939 The access mode for the socket.
11940 Defaults to @samp{"0600"}.
11943 @deftypevr {@code{unix-listener-configuration} parameter} string user
11944 The user to own the socket.
11945 Defaults to @samp{""}.
11948 @deftypevr {@code{unix-listener-configuration} parameter} string group
11949 The group to own the socket.
11950 Defaults to @samp{""}.
11954 Available @code{fifo-listener-configuration} fields are:
11956 @deftypevr {@code{fifo-listener-configuration} parameter} string path
11957 Path to the file, relative to @code{base-dir} field. This is also used as
11961 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
11962 The access mode for the socket.
11963 Defaults to @samp{"0600"}.
11966 @deftypevr {@code{fifo-listener-configuration} parameter} string user
11967 The user to own the socket.
11968 Defaults to @samp{""}.
11971 @deftypevr {@code{fifo-listener-configuration} parameter} string group
11972 The group to own the socket.
11973 Defaults to @samp{""}.
11977 Available @code{inet-listener-configuration} fields are:
11979 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
11980 The protocol to listen for.
11983 @deftypevr {@code{inet-listener-configuration} parameter} string address
11984 The address on which to listen, or empty for all addresses.
11985 Defaults to @samp{""}.
11988 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
11989 The port on which to listen.
11992 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
11993 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
11995 Defaults to @samp{#t}.
12000 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
12001 Number of connections to handle before starting a new process.
12002 Typically the only useful values are 0 (unlimited) or 1. 1 is more
12003 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
12004 Defaults to @samp{1}.
12007 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
12008 Number of processes to always keep waiting for more connections.
12009 Defaults to @samp{0}.
12012 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
12013 If you set @samp{service-count 0}, you probably need to grow
12015 Defaults to @samp{256000000}.
12020 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
12021 Dict configuration, as created by the @code{dict-configuration}
12024 Available @code{dict-configuration} fields are:
12026 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
12027 A list of key-value pairs that this dict should hold.
12028 Defaults to @samp{()}.
12033 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
12034 A list of passdb configurations, each one created by the
12035 @code{passdb-configuration} constructor.
12037 Available @code{passdb-configuration} fields are:
12039 @deftypevr {@code{passdb-configuration} parameter} string driver
12040 The driver that the passdb should use. Valid values include
12041 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
12043 Defaults to @samp{"pam"}.
12046 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
12047 Space separated list of arguments to the passdb driver.
12048 Defaults to @samp{""}.
12053 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
12054 List of userdb configurations, each one created by the
12055 @code{userdb-configuration} constructor.
12057 Available @code{userdb-configuration} fields are:
12059 @deftypevr {@code{userdb-configuration} parameter} string driver
12060 The driver that the userdb should use. Valid values include
12061 @samp{passwd} and @samp{static}.
12062 Defaults to @samp{"passwd"}.
12065 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
12066 Space separated list of arguments to the userdb driver.
12067 Defaults to @samp{""}.
12070 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
12071 Override fields from passwd.
12072 Defaults to @samp{()}.
12077 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
12078 Plug-in configuration, created by the @code{plugin-configuration}
12082 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
12083 List of namespaces. Each item in the list is created by the
12084 @code{namespace-configuration} constructor.
12086 Available @code{namespace-configuration} fields are:
12088 @deftypevr {@code{namespace-configuration} parameter} string name
12089 Name for this namespace.
12092 @deftypevr {@code{namespace-configuration} parameter} string type
12093 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
12094 Defaults to @samp{"private"}.
12097 @deftypevr {@code{namespace-configuration} parameter} string separator
12098 Hierarchy separator to use. You should use the same separator for
12099 all namespaces or some clients get confused. @samp{/} is usually a good
12100 one. The default however depends on the underlying mail storage
12102 Defaults to @samp{""}.
12105 @deftypevr {@code{namespace-configuration} parameter} string prefix
12106 Prefix required to access this namespace. This needs to be
12107 different for all namespaces. For example @samp{Public/}.
12108 Defaults to @samp{""}.
12111 @deftypevr {@code{namespace-configuration} parameter} string location
12112 Physical location of the mailbox. This is in the same format as
12113 mail_location, which is also the default for it.
12114 Defaults to @samp{""}.
12117 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
12118 There can be only one INBOX, and this setting defines which
12120 Defaults to @samp{#f}.
12123 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
12124 If namespace is hidden, it's not advertised to clients via NAMESPACE
12125 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
12126 useful when converting from another server with different namespaces
12127 which you want to deprecate but still keep working. For example you can
12128 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
12130 Defaults to @samp{#f}.
12133 @deftypevr {@code{namespace-configuration} parameter} boolean list?
12134 Show the mailboxes under this namespace with the LIST command. This
12135 makes the namespace visible for clients that do not support the NAMESPACE
12136 extension. The special @code{children} value lists child mailboxes, but
12137 hides the namespace prefix.
12138 Defaults to @samp{#t}.
12141 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
12142 Namespace handles its own subscriptions. If set to @code{#f}, the
12143 parent namespace handles them. The empty prefix should always have this
12145 Defaults to @samp{#t}.
12148 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
12149 List of predefined mailboxes in this namespace.
12150 Defaults to @samp{()}.
12152 Available @code{mailbox-configuration} fields are:
12154 @deftypevr {@code{mailbox-configuration} parameter} string name
12155 Name for this mailbox.
12158 @deftypevr {@code{mailbox-configuration} parameter} string auto
12159 @samp{create} will automatically create this mailbox.
12160 @samp{subscribe} will both create and subscribe to the mailbox.
12161 Defaults to @samp{"no"}.
12164 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
12165 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
12166 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
12167 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
12168 Defaults to @samp{()}.
12175 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
12176 Base directory where to store runtime data.
12177 Defaults to @samp{"/var/run/dovecot/"}.
12180 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
12181 Greeting message for clients.
12182 Defaults to @samp{"Dovecot ready."}.
12185 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
12186 List of trusted network ranges. Connections from these IPs are
12187 allowed to override their IP addresses and ports (for logging and for
12188 authentication checks). @samp{disable-plaintext-auth} is also ignored
12189 for these networks. Typically you would specify your IMAP proxy servers
12191 Defaults to @samp{()}.
12194 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
12195 List of login access check sockets (e.g. tcpwrap).
12196 Defaults to @samp{()}.
12199 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
12200 Show more verbose process titles (in ps). Currently shows user name
12201 and IP address. Useful for seeing who is actually using the IMAP
12202 processes (e.g. shared mailboxes or if the same uid is used for multiple
12204 Defaults to @samp{#f}.
12207 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
12208 Should all processes be killed when Dovecot master process shuts down.
12209 Setting this to @code{#f} means that Dovecot can be upgraded without
12210 forcing existing client connections to close (although that could also
12211 be a problem if the upgrade is e.g. due to a security fix).
12212 Defaults to @samp{#t}.
12215 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
12216 If non-zero, run mail commands via this many connections to doveadm
12217 server, instead of running them directly in the same process.
12218 Defaults to @samp{0}.
12221 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
12222 UNIX socket or host:port used for connecting to doveadm server.
12223 Defaults to @samp{"doveadm-server"}.
12226 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
12227 List of environment variables that are preserved on Dovecot startup
12228 and passed down to all of its child processes. You can also give
12229 key=value pairs to always set specific settings.
12232 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
12233 Disable LOGIN command and all other plaintext authentications unless
12234 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
12235 matches the local IP (i.e. you're connecting from the same computer),
12236 the connection is considered secure and plaintext authentication is
12237 allowed. See also ssl=required setting.
12238 Defaults to @samp{#t}.
12241 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
12242 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
12243 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
12244 for caching to be used.
12245 Defaults to @samp{0}.
12248 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
12249 Time to live for cached data. After TTL expires the cached record
12250 is no longer used, *except* if the main database lookup returns internal
12251 failure. We also try to handle password changes automatically: If
12252 user's previous authentication was successful, but this one wasn't, the
12253 cache isn't used. For now this works only with plaintext
12255 Defaults to @samp{"1 hour"}.
12258 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
12259 TTL for negative hits (user not found, password mismatch).
12260 0 disables caching them completely.
12261 Defaults to @samp{"1 hour"}.
12264 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
12265 List of realms for SASL authentication mechanisms that need them.
12266 You can leave it empty if you don't want to support multiple realms.
12267 Many clients simply use the first one listed here, so keep the default
12269 Defaults to @samp{()}.
12272 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
12273 Default realm/domain to use if none was specified. This is used for
12274 both SASL realms and appending @@domain to username in plaintext
12276 Defaults to @samp{""}.
12279 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
12280 List of allowed characters in username. If the user-given username
12281 contains a character not listed in here, the login automatically fails.
12282 This is just an extra check to make sure user can't exploit any
12283 potential quote escaping vulnerabilities with SQL/LDAP databases. If
12284 you want to allow all characters, set this value to empty.
12285 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
12288 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
12289 Username character translations before it's looked up from
12290 databases. The value contains series of from -> to characters. For
12291 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
12292 translated to @samp{@@}.
12293 Defaults to @samp{""}.
12296 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
12297 Username formatting before it's looked up from databases. You can
12298 use the standard variables here, e.g. %Lu would lowercase the username,
12299 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
12300 change the @samp{@@} into @samp{-AT-}. This translation is done after
12301 @samp{auth-username-translation} changes.
12302 Defaults to @samp{"%Lu"}.
12305 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
12306 If you want to allow master users to log in by specifying the master
12307 username within the normal username string (i.e. not using SASL
12308 mechanism's support for it), you can specify the separator character
12309 here. The format is then <username><separator><master username>.
12310 UW-IMAP uses @samp{*} as the separator, so that could be a good
12312 Defaults to @samp{""}.
12315 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
12316 Username to use for users logging in with ANONYMOUS SASL
12318 Defaults to @samp{"anonymous"}.
12321 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
12322 Maximum number of dovecot-auth worker processes. They're used to
12323 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
12324 They're automatically created and destroyed as needed.
12325 Defaults to @samp{30}.
12328 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
12329 Host name to use in GSSAPI principal names. The default is to use
12330 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
12331 allow all keytab entries.
12332 Defaults to @samp{""}.
12335 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
12336 Kerberos keytab to use for the GSSAPI mechanism. Will use the
12337 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
12338 need to change the auth service to run as root to be able to read this
12340 Defaults to @samp{""}.
12343 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
12344 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
12345 and @samp{ntlm-auth} helper.
12346 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
12347 Defaults to @samp{#f}.
12350 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
12351 Path for Samba's @samp{ntlm-auth} helper binary.
12352 Defaults to @samp{"/usr/bin/ntlm_auth"}.
12355 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
12356 Time to delay before replying to failed authentications.
12357 Defaults to @samp{"2 secs"}.
12360 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
12361 Require a valid SSL client certificate or the authentication
12363 Defaults to @samp{#f}.
12366 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
12367 Take the username from client's SSL certificate, using
12368 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
12370 Defaults to @samp{#f}.
12373 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
12374 List of wanted authentication mechanisms. Supported mechanisms are:
12375 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
12376 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
12377 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
12378 @samp{disable-plaintext-auth} setting.
12381 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
12382 List of IPs or hostnames to all director servers, including ourself.
12383 Ports can be specified as ip:port. The default port is the same as what
12384 director service's @samp{inet-listener} is using.
12385 Defaults to @samp{()}.
12388 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
12389 List of IPs or hostnames to all backend mail servers. Ranges are
12390 allowed too, like 10.0.0.10-10.0.0.30.
12391 Defaults to @samp{()}.
12394 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
12395 How long to redirect users to a specific server after it no longer
12396 has any connections.
12397 Defaults to @samp{"15 min"}.
12400 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
12401 TCP/IP port that accepts doveadm connections (instead of director
12402 connections) If you enable this, you'll also need to add
12403 @samp{inet-listener} for the port.
12404 Defaults to @samp{0}.
12407 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
12408 How the username is translated before being hashed. Useful values
12409 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
12410 are shared within domain.
12411 Defaults to @samp{"%Lu"}.
12414 @deftypevr {@code{dovecot-configuration} parameter} string log-path
12415 Log file to use for error messages. @samp{syslog} logs to syslog,
12416 @samp{/dev/stderr} logs to stderr.
12417 Defaults to @samp{"syslog"}.
12420 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
12421 Log file to use for informational messages. Defaults to
12423 Defaults to @samp{""}.
12426 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
12427 Log file to use for debug messages. Defaults to
12428 @samp{info-log-path}.
12429 Defaults to @samp{""}.
12432 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
12433 Syslog facility to use if you're logging to syslog. Usually if you
12434 don't want to use @samp{mail}, you'll use local0..local7. Also other
12435 standard facilities are supported.
12436 Defaults to @samp{"mail"}.
12439 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
12440 Log unsuccessful authentication attempts and the reasons why they
12442 Defaults to @samp{#f}.
12445 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
12446 In case of password mismatches, log the attempted password. Valid
12447 values are no, plain and sha1. sha1 can be useful for detecting brute
12448 force password attempts vs. user simply trying the same password over
12449 and over again. You can also truncate the value to n chars by appending
12450 ":n" (e.g. sha1:6).
12451 Defaults to @samp{#f}.
12454 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
12455 Even more verbose logging for debugging purposes. Shows for example
12457 Defaults to @samp{#f}.
12460 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
12461 In case of password mismatches, log the passwords and used scheme so
12462 the problem can be debugged. Enabling this also enables
12464 Defaults to @samp{#f}.
12467 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
12468 Enable mail process debugging. This can help you figure out why
12469 Dovecot isn't finding your mails.
12470 Defaults to @samp{#f}.
12473 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
12474 Show protocol level SSL errors.
12475 Defaults to @samp{#f}.
12478 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
12479 Prefix for each line written to log file. % codes are in
12480 strftime(3) format.
12481 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
12484 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
12485 List of elements we want to log. The elements which have a
12486 non-empty variable value are joined together to form a comma-separated
12490 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
12491 Login log format. %s contains @samp{login-log-format-elements}
12492 string, %$ contains the data we want to log.
12493 Defaults to @samp{"%$: %s"}.
12496 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
12497 Log prefix for mail processes. See doc/wiki/Variables.txt for list
12498 of possible variables you can use.
12499 Defaults to @samp{"\"%s(%u): \""}.
12502 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
12503 Format to use for logging mail deliveries. You can use variables:
12506 Delivery status message (e.g. @samp{saved to INBOX})
12518 Defaults to @samp{"msgid=%m: %$"}.
12521 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
12522 Location for users' mailboxes. The default is empty, which means
12523 that Dovecot tries to find the mailboxes automatically. This won't work
12524 if the user doesn't yet have any mail, so you should explicitly tell
12525 Dovecot the full location.
12527 If you're using mbox, giving a path to the INBOX
12528 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
12529 where the other mailboxes are kept. This is called the "root mail
12530 directory", and it must be the first path given in the
12531 @samp{mail-location} setting.
12533 There are a few special variables you can use, eg.:
12539 user part in user@@domain, same as %u if there's no domain
12541 domain part in user@@domain, empty if there's no domain
12546 See doc/wiki/Variables.txt for full list. Some examples:
12548 @item maildir:~/Maildir
12549 @item mbox:~/mail:INBOX=/var/mail/%u
12550 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
12552 Defaults to @samp{""}.
12555 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
12556 System user and group used to access mails. If you use multiple,
12557 userdb can override these by returning uid or gid fields. You can use
12558 either numbers or names. <doc/wiki/UserIds.txt>.
12559 Defaults to @samp{""}.
12562 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
12564 Defaults to @samp{""}.
12567 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
12568 Group to enable temporarily for privileged operations. Currently
12569 this is used only with INBOX when either its initial creation or
12570 dotlocking fails. Typically this is set to "mail" to give access to
12572 Defaults to @samp{""}.
12575 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
12576 Grant access to these supplementary groups for mail processes.
12577 Typically these are used to set up access to shared mailboxes. Note
12578 that it may be dangerous to set these if users can create
12579 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
12580 could allow a user to delete others' mailboxes, or ln -s
12581 /secret/shared/box ~/mail/mybox would allow reading it).
12582 Defaults to @samp{""}.
12585 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12586 Allow full file system access to clients. There's no access checks
12587 other than what the operating system does for the active UID/GID. It
12588 works with both maildir and mboxes, allowing you to prefix mailboxes
12589 names with e.g. /path/ or ~user/.
12590 Defaults to @samp{#f}.
12593 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12594 Don't use mmap() at all. This is required if you store indexes to
12595 shared file systems (NFS or clustered file system).
12596 Defaults to @samp{#f}.
12599 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12600 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12601 supports @samp{O_EXCL} since version 3, so this should be safe to use
12602 nowadays by default.
12603 Defaults to @samp{#t}.
12606 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12607 When to use fsync() or fdatasync() calls:
12610 Whenever necessary to avoid losing important data
12612 Useful with e.g. NFS when write()s are delayed
12614 Never use it (best performance, but crashes can lose data).
12616 Defaults to @samp{"optimized"}.
12619 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12620 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12621 NFS caches whenever needed. If you're using only a single mail server
12623 Defaults to @samp{#f}.
12626 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12627 Mail index files also exist in NFS. Setting this to yes requires
12628 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12629 Defaults to @samp{#f}.
12632 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12633 Locking method for index files. Alternatives are fcntl, flock and
12634 dotlock. Dotlocking uses some tricks which may create more disk I/O
12635 than other locking methods. NFS users: flock doesn't work, remember to
12636 change @samp{mmap-disable}.
12637 Defaults to @samp{"fcntl"}.
12640 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12641 Directory in which LDA/LMTP temporarily stores incoming mails >128
12643 Defaults to @samp{"/tmp"}.
12646 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12647 Valid UID range for users. This is mostly to make sure that users can't
12648 log in as daemons or other system users. Note that denying root logins is
12649 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12651 Defaults to @samp{500}.
12654 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12656 Defaults to @samp{0}.
12659 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12660 Valid GID range for users. Users having non-valid GID as primary group ID
12661 aren't allowed to log in. If user belongs to supplementary groups with
12662 non-valid GIDs, those groups are not set.
12663 Defaults to @samp{1}.
12666 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12668 Defaults to @samp{0}.
12671 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12672 Maximum allowed length for mail keyword name. It's only forced when
12673 trying to create new keywords.
12674 Defaults to @samp{50}.
12677 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12678 List of directories under which chrooting is allowed for mail
12679 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12680 too). This setting doesn't affect @samp{login-chroot}
12681 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12682 "/./" in home dirs are ignored. WARNING: Never add directories here
12683 which local users can modify, that may lead to root exploit. Usually
12684 this should be done only if you don't allow shell access for users.
12685 <doc/wiki/Chrooting.txt>.
12686 Defaults to @samp{()}.
12689 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12690 Default chroot directory for mail processes. This can be overridden
12691 for specific users in user database by giving /./ in user's home
12692 directory (e.g. /home/./user chroots into /home). Note that usually
12693 there is no real need to do chrooting, Dovecot doesn't allow users to
12694 access files outside their mail directory anyway. If your home
12695 directories are prefixed with the chroot directory, append "/." to
12696 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12697 Defaults to @samp{""}.
12700 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12701 UNIX socket path to master authentication server to find users.
12702 This is used by imap (for shared users) and lda.
12703 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12706 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12707 Directory where to look up mail plugins.
12708 Defaults to @samp{"/usr/lib/dovecot"}.
12711 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12712 List of plugins to load for all services. Plugins specific to IMAP,
12713 LDA, etc. are added to this list in their own .conf files.
12714 Defaults to @samp{()}.
12717 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12718 The minimum number of mails in a mailbox before updates are done to
12719 cache file. This allows optimizing Dovecot's behavior to do less disk
12720 writes at the cost of more disk reads.
12721 Defaults to @samp{0}.
12724 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12725 When IDLE command is running, mailbox is checked once in a while to
12726 see if there are any new mails or other changes. This setting defines
12727 the minimum time to wait between those checks. Dovecot can also use
12728 dnotify, inotify and kqueue to find out immediately when changes
12730 Defaults to @samp{"30 secs"}.
12733 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12734 Save mails with CR+LF instead of plain LF. This makes sending those
12735 mails take less CPU, especially with sendfile() syscall with Linux and
12736 FreeBSD. But it also creates a bit more disk I/O which may just make it
12737 slower. Also note that if other software reads the mboxes/maildirs,
12738 they may handle the extra CRs wrong and cause problems.
12739 Defaults to @samp{#f}.
12742 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12743 By default LIST command returns all entries in maildir beginning
12744 with a dot. Enabling this option makes Dovecot return only entries
12745 which are directories. This is done by stat()ing each entry, so it
12746 causes more disk I/O.
12747 (For systems setting struct @samp{dirent->d_type} this check is free
12748 and it's done always regardless of this setting).
12749 Defaults to @samp{#f}.
12752 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12753 When copying a message, do it with hard links whenever possible.
12754 This makes the performance much better, and it's unlikely to have any
12756 Defaults to @samp{#t}.
12759 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12760 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12761 directory only when its mtime changes unexpectedly or when we can't find
12762 the mail otherwise.
12763 Defaults to @samp{#f}.
12766 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12767 Which locking methods to use for locking mbox. There are four
12772 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12773 solution. If you want to use /var/mail/ like directory, the users will
12774 need write access to that directory.
12776 Same as dotlock, but if it fails because of permissions or because there
12777 isn't enough disk space, just skip it.
12779 Use this if possible. Works with NFS too if lockd is used.
12781 May not exist in all systems. Doesn't work with NFS.
12783 May not exist in all systems. Doesn't work with NFS.
12786 You can use multiple locking methods; if you do the order they're declared
12787 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12788 locking methods as well. Some operating systems don't allow using some of
12789 them simultaneously.
12792 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12796 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12797 Maximum time to wait for lock (all of them) before aborting.
12798 Defaults to @samp{"5 mins"}.
12801 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12802 If dotlock exists but the mailbox isn't modified in any way,
12803 override the lock file after this much time.
12804 Defaults to @samp{"2 mins"}.
12807 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12808 When mbox changes unexpectedly we have to fully read it to find out
12809 what changed. If the mbox is large this can take a long time. Since
12810 the change is usually just a newly appended mail, it'd be faster to
12811 simply read the new mails. If this setting is enabled, Dovecot does
12812 this but still safely fallbacks to re-reading the whole mbox file
12813 whenever something in mbox isn't how it's expected to be. The only real
12814 downside to this setting is that if some other MUA changes message
12815 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12816 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12817 Defaults to @samp{#t}.
12820 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12821 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12822 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12823 @samp{mbox-dirty-syncs} is ignored.
12824 Defaults to @samp{#f}.
12827 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12828 Delay writing mbox headers until doing a full write sync (EXPUNGE
12829 and CHECK commands and when closing the mailbox). This is especially
12830 useful for POP3 where clients often delete all mails. The downside is
12831 that our changes aren't immediately visible to other MUAs.
12832 Defaults to @samp{#t}.
12835 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12836 If mbox size is smaller than this (e.g. 100k), don't write index
12837 files. If an index file already exists it's still read, just not
12839 Defaults to @samp{0}.
12842 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12843 Maximum dbox file size until it's rotated.
12844 Defaults to @samp{2000000}.
12847 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12848 Maximum dbox file age until it's rotated. Typically in days. Day
12849 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12851 Defaults to @samp{"1d"}.
12854 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12855 When creating new mdbox files, immediately preallocate their size to
12856 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12857 with some file systems (ext4, xfs).
12858 Defaults to @samp{#f}.
12861 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12862 sdbox and mdbox support saving mail attachments to external files,
12863 which also allows single instance storage for them. Other backends
12864 don't support this for now.
12866 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12868 Directory root where to store mail attachments. Disabled, if empty.
12869 Defaults to @samp{""}.
12872 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12873 Attachments smaller than this aren't saved externally. It's also
12874 possible to write a plugin to disable saving specific attachments
12876 Defaults to @samp{128000}.
12879 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12880 File system backend to use for saving attachments:
12883 No SiS done by Dovecot (but this might help FS's own deduplication)
12885 SiS with immediate byte-by-byte comparison during saving
12886 @item sis-queue posix
12887 SiS with delayed comparison and deduplication.
12889 Defaults to @samp{"sis posix"}.
12892 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
12893 Hash format to use in attachment filenames. You can add any text and
12894 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
12895 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
12896 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
12897 Defaults to @samp{"%@{sha1@}"}.
12900 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
12902 Defaults to @samp{100}.
12905 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
12907 Defaults to @samp{1000}.
12910 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
12911 Default VSZ (virtual memory size) limit for service processes.
12912 This is mainly intended to catch and kill processes that leak memory
12913 before they eat up everything.
12914 Defaults to @samp{256000000}.
12917 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
12918 Login user is internally used by login processes. This is the most
12919 untrusted user in Dovecot system. It shouldn't have access to anything
12921 Defaults to @samp{"dovenull"}.
12924 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
12925 Internal user is used by unprivileged processes. It should be
12926 separate from login user, so that login processes can't disturb other
12928 Defaults to @samp{"dovecot"}.
12931 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
12932 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
12933 Defaults to @samp{"required"}.
12936 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
12937 PEM encoded X.509 SSL/TLS certificate (public key).
12938 Defaults to @samp{"</etc/dovecot/default.pem"}.
12941 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
12942 PEM encoded SSL/TLS private key. The key is opened before
12943 dropping root privileges, so keep the key file unreadable by anyone but
12945 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
12948 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
12949 If key file is password protected, give the password here.
12950 Alternatively give it when starting dovecot with -p parameter. Since
12951 this file is often world-readable, you may want to place this setting
12952 instead to a different.
12953 Defaults to @samp{""}.
12956 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
12957 PEM encoded trusted certificate authority. Set this only if you
12958 intend to use @samp{ssl-verify-client-cert? #t}. The file should
12959 contain the CA certificate(s) followed by the matching
12960 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
12961 Defaults to @samp{""}.
12964 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
12965 Require that CRL check succeeds for client certificates.
12966 Defaults to @samp{#t}.
12969 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
12970 Request client to send a certificate. If you also want to require
12971 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
12972 Defaults to @samp{#f}.
12975 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
12976 Which field from certificate to use for username. commonName and
12977 x500UniqueIdentifier are the usual choices. You'll also need to set
12978 @samp{auth-ssl-username-from-cert? #t}.
12979 Defaults to @samp{"commonName"}.
12982 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
12983 How often to regenerate the SSL parameters file. Generation is
12984 quite CPU intensive operation. The value is in hours, 0 disables
12985 regeneration entirely.
12986 Defaults to @samp{168}.
12989 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
12990 SSL protocols to use.
12991 Defaults to @samp{"!SSLv2"}.
12994 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
12995 SSL ciphers to use.
12996 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
12999 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
13000 SSL crypto device to use, for valid values run "openssl engine".
13001 Defaults to @samp{""}.
13004 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
13005 Address to use when sending rejection mails.
13006 %d expands to recipient domain.
13007 Defaults to @samp{"postmaster@@%d"}.
13010 @deftypevr {@code{dovecot-configuration} parameter} string hostname
13011 Hostname to use in various parts of sent mails (e.g. in Message-Id)
13012 and in LMTP replies. Default is the system's real hostname@@domain.
13013 Defaults to @samp{""}.
13016 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
13017 If user is over quota, return with temporary failure instead of
13019 Defaults to @samp{#f}.
13022 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
13023 Binary to use for sending mails.
13024 Defaults to @samp{"/usr/sbin/sendmail"}.
13027 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
13028 If non-empty, send mails via this SMTP host[:port] instead of
13030 Defaults to @samp{""}.
13033 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
13034 Subject: header to use for rejection mails. You can use the same
13035 variables as for @samp{rejection-reason} below.
13036 Defaults to @samp{"Rejected: %s"}.
13039 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
13040 Human readable error message for rejection mails. You can use
13053 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
13056 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
13057 Delimiter character between local-part and detail in email
13059 Defaults to @samp{"+"}.
13062 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
13063 Header where the original recipient address (SMTP's RCPT TO:
13064 address) is taken from if not available elsewhere. With dovecot-lda -a
13065 parameter overrides this. A commonly used header for this is
13067 Defaults to @samp{""}.
13070 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
13071 Should saving a mail to a nonexistent mailbox automatically create
13073 Defaults to @samp{#f}.
13076 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
13077 Should automatically created mailboxes be also automatically
13079 Defaults to @samp{#f}.
13082 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
13083 Maximum IMAP command line length. Some clients generate very long
13084 command lines with huge mailboxes, so you may need to raise this if you
13085 get "Too long argument" or "IMAP command line too large" errors
13087 Defaults to @samp{64000}.
13090 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
13091 IMAP logout format string:
13094 total number of bytes read from client
13096 total number of bytes sent to client.
13098 Defaults to @samp{"in=%i out=%o"}.
13101 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
13102 Override the IMAP CAPABILITY response. If the value begins with '+',
13103 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
13104 Defaults to @samp{""}.
13107 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
13108 How long to wait between "OK Still here" notifications when client
13110 Defaults to @samp{"2 mins"}.
13113 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
13114 ID field names and values to send to clients. Using * as the value
13115 makes Dovecot use the default value. The following fields have default
13116 values currently: name, version, os, os-version, support-url,
13118 Defaults to @samp{""}.
13121 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
13122 ID fields sent by client to log. * means everything.
13123 Defaults to @samp{""}.
13126 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
13127 Workarounds for various client bugs:
13130 @item delay-newmail
13131 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
13132 CHECK commands. Some clients ignore them otherwise, for example OSX
13133 Mail (<v2.1). Outlook Express breaks more badly though, without this it
13134 may show user "Message no longer in server" errors. Note that OE6
13135 still breaks even with this workaround if synchronization is set to
13138 @item tb-extra-mailbox-sep
13139 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
13140 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
13141 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
13143 @item tb-lsub-flags
13144 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
13145 This makes Thunderbird realize they aren't selectable and show them
13146 greyed out, instead of only later giving "not selectable" popup error.
13148 Defaults to @samp{()}.
13151 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
13152 Host allowed in URLAUTH URLs sent by client. "*" allows all.
13153 Defaults to @samp{""}.
13157 Whew! Lots of configuration options. The nice thing about it though is
13158 that GuixSD has a complete interface to Dovecot's configuration
13159 language. This allows not only a nice way to declare configurations,
13160 but also offers reflective capabilities as well: users can write code to
13161 inspect and transform configurations from within Scheme.
13163 However, it could be that you just want to get a @code{dovecot.conf} up
13164 and running. In that case, you can pass an
13165 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
13166 @code{dovecot-service}. As its name indicates, an opaque configuration
13167 does not have easy reflective capabilities.
13169 Available @code{opaque-dovecot-configuration} fields are:
13171 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
13172 The dovecot package.
13175 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
13176 The contents of the @code{dovecot.conf}, as a string.
13179 For example, if your @code{dovecot.conf} is just the empty string, you
13180 could instantiate a dovecot service like this:
13183 (dovecot-service #:config
13184 (opaque-dovecot-configuration
13188 @subsubheading OpenSMTPD Service
13190 @deffn {Scheme Variable} opensmtpd-service-type
13191 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
13192 service, whose value should be an @code{opensmtpd-configuration} object
13193 as in this example:
13196 (service opensmtpd-service-type
13197 (opensmtpd-configuration
13198 (config-file (local-file "./my-smtpd.conf"))))
13202 @deftp {Data Type} opensmtpd-configuration
13203 Data type representing the configuration of opensmtpd.
13206 @item @code{package} (default: @var{opensmtpd})
13207 Package object of the OpenSMTPD SMTP server.
13209 @item @code{config-file} (default: @var{%default-opensmtpd-file})
13210 File-like object of the OpenSMTPD configuration file to use. By default
13211 it listens on the loopback network interface, and allows for mail from
13212 users and daemons on the local machine, as well as permitting email to
13213 remote servers. Run @command{man smtpd.conf} for more information.
13218 @subsubheading Exim Service
13220 @cindex mail transfer agent (MTA)
13221 @cindex MTA (mail transfer agent)
13224 @deffn {Scheme Variable} exim-service-type
13225 This is the type of the @uref{https://exim.org, Exim} mail transfer
13226 agent (MTA), whose value should be an @code{exim-configuration} object
13227 as in this example:
13230 (service exim-service-type
13231 (exim-configuration
13232 (config-file (local-file "./my-exim.conf"))))
13236 In order to use an @code{exim-service-type} service you must also have a
13237 @code{mail-aliases-service-type} service present in your
13238 @code{operating-system} (even if it has no aliases).
13240 @deftp {Data Type} exim-configuration
13241 Data type representing the configuration of exim.
13244 @item @code{package} (default: @var{exim})
13245 Package object of the Exim server.
13247 @item @code{config-file} (default: @code{#f})
13248 File-like object of the Exim configuration file to use. If its value is
13249 @code{#f} then use the default configuration file from the package
13250 provided in @code{package}. The resulting configuration file is loaded
13251 after setting the @code{exim_user} and @code{exim_group} configuration
13257 @subsubheading Mail Aliases Service
13259 @cindex email aliases
13260 @cindex aliases, for email addresses
13262 @deffn {Scheme Variable} mail-aliases-service-type
13263 This is the type of the service which provides @code{/etc/aliases},
13264 specifying how to deliver mail to users on this system.
13267 (service mail-aliases-service-type
13268 '(("postmaster" "bob")
13269 ("bob" "bob@@example.com" "bob@@example2.com")))
13273 The configuration for a @code{mail-aliases-service-type} service is an
13274 association list denoting how to deliver mail that comes to this
13275 system. Each entry is of the form @code{(alias addresses ...)}, with
13276 @code{alias} specifying the local alias and @code{addresses} specifying
13277 where to deliver this user's mail.
13279 The aliases aren't required to exist as users on the local system. In
13280 the above example, there doesn't need to be a @code{postmaster} entry in
13281 the @code{operating-system}'s @code{user-accounts} in order to deliver
13282 the @code{postmaster} mail to @code{bob} (which subsequently would
13283 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
13285 @node Messaging Services
13286 @subsubsection Messaging Services
13291 The @code{(gnu services messaging)} module provides Guix service
13292 definitions for messaging services: currently only Prosody is supported.
13294 @subsubheading Prosody Service
13296 @deffn {Scheme Variable} prosody-service-type
13297 This is the type for the @uref{http://prosody.im, Prosody XMPP
13298 communication server}. Its value must be a @code{prosody-configuration}
13299 record as in this example:
13302 (service prosody-service-type
13303 (prosody-configuration
13304 (modules-enabled (cons "groups" %default-modules-enabled))
13307 (int-component-configuration
13308 (hostname "conference.example.net")
13310 (mod-muc (mod-muc-configuration)))))
13313 (virtualhost-configuration
13314 (domain "example.net"))))))
13317 See below for details about @code{prosody-configuration}.
13321 By default, Prosody does not need much configuration. Only one
13322 @code{virtualhosts} field is needed: it specifies the domain you wish
13325 Prosodyctl will help you generate X.509 certificates and keys:
13328 prosodyctl cert request example.net
13331 The available configuration parameters follow. Each parameter
13332 definition is preceded by its type; for example, @samp{string-list foo}
13333 indicates that the @code{foo} parameter should be specified as a list of
13334 strings. Types starting with @code{maybe-} denote parameters that won't
13335 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
13337 There is also a way to specify the configuration as a string, if you
13338 have an old @code{prosody.cfg.lua} file that you want to port over from
13339 some other system; see the end for more details.
13341 @c The following documentation was initially generated by
13342 @c (generate-documentation) in (gnu services messaging). Manually maintained
13343 @c documentation is better, so we shouldn't hesitate to edit below as
13344 @c needed. However if the change you want to make to this documentation
13345 @c can be done in an automated way, it's probably easier to change
13346 @c (generate-documentation) than to make it below and have to deal with
13347 @c the churn as Prosody updates.
13349 Available @code{prosody-configuration} fields are:
13351 @deftypevr {@code{prosody-configuration} parameter} package prosody
13352 The Prosody package.
13355 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
13356 Location of the Prosody data storage directory. See
13357 @url{http://prosody.im/doc/configure}.
13358 Defaults to @samp{"/var/lib/prosody"}.
13361 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
13362 Additional plugin directories. They are searched in all the specified
13363 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
13364 Defaults to @samp{()}.
13367 @deftypevr {@code{prosody-configuration} parameter} string-list admins
13368 This is a list of accounts that are admins for the server. Note that you
13369 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
13370 @url{http://prosody.im/doc/creating_accounts}.
13371 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
13372 Defaults to @samp{()}.
13375 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
13376 Enable use of libevent for better performance under high load. See
13377 @url{http://prosody.im/doc/libevent}.
13378 Defaults to @samp{#f}.
13381 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
13382 This is the list of modules Prosody will load on startup. It looks for
13383 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
13384 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
13385 Defaults to @samp{%default-modules-enabled}.
13388 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
13389 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
13390 should you want to disable them then add them to this list.
13391 Defaults to @samp{()}.
13394 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
13395 Path to a text file where the shared groups are defined. If this path is
13396 empty then @samp{mod_groups} does nothing. See
13397 @url{http://prosody.im/doc/modules/mod_groups}.
13398 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
13401 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
13402 Disable account creation by default, for security. See
13403 @url{http://prosody.im/doc/creating_accounts}.
13404 Defaults to @samp{#f}.
13407 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
13408 These are the SSL/TLS-related settings. Most of them are disabled so to
13409 use Prosody's defaults. If you do not completely understand these options, do
13410 not add them to your config, it is easy to lower the security of your server
13411 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
13413 Available @code{ssl-configuration} fields are:
13415 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
13416 This determines what handshake to use.
13419 @deftypevr {@code{ssl-configuration} parameter} file-name key
13420 Path to your private key file, relative to @code{/etc/prosody}.
13421 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
13424 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
13425 Path to your certificate file, relative to @code{/etc/prosody}.
13426 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
13429 @deftypevr {@code{ssl-configuration} parameter} file-name capath
13430 Path to directory containing root certificates that you wish Prosody to
13431 trust when verifying the certificates of remote servers.
13432 Defaults to @samp{"/etc/ssl/certs"}.
13435 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
13436 Path to a file containing root certificates that you wish Prosody to trust.
13437 Similar to @code{capath} but with all certificates concatenated together.
13440 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
13441 A list of verification options (these mostly map to OpenSSL's
13442 @code{set_verify()} flags).
13445 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
13446 A list of general options relating to SSL/TLS. These map to OpenSSL's
13447 @code{set_options()}. For a full list of options available in LuaSec, see the
13451 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
13452 How long a chain of certificate authorities to check when looking for a
13453 trusted root certificate.
13456 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
13457 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
13458 clients, and in what order.
13461 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
13462 A path to a file containing parameters for Diffie-Hellman key exchange. You
13463 can create such a file with:
13464 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
13467 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
13468 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
13469 @samp{"secp384r1"}.
13472 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
13473 A list of "extra" verification options.
13476 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
13477 Password for encrypted private keys.
13482 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
13483 Whether to force all client-to-server connections to be encrypted or not.
13484 See @url{http://prosody.im/doc/modules/mod_tls}.
13485 Defaults to @samp{#f}.
13488 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
13489 Whether to force all server-to-server connections to be encrypted or not.
13490 See @url{http://prosody.im/doc/modules/mod_tls}.
13491 Defaults to @samp{#f}.
13494 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
13495 Whether to require encryption and certificate authentication. This
13496 provides ideal security, but requires servers you communicate with to support
13497 encryption AND present valid, trusted certificates. See
13498 @url{http://prosody.im/doc/s2s#security}.
13499 Defaults to @samp{#f}.
13502 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
13503 Many servers don't support encryption or have invalid or self-signed
13504 certificates. You can list domains here that will not be required to
13505 authenticate using certificates. They will be authenticated using DNS. See
13506 @url{http://prosody.im/doc/s2s#security}.
13507 Defaults to @samp{()}.
13510 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
13511 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
13512 valid certificates for some domains by specifying a list here. See
13513 @url{http://prosody.im/doc/s2s#security}.
13514 Defaults to @samp{()}.
13517 @deftypevr {@code{prosody-configuration} parameter} string authentication
13518 Select the authentication backend to use. The default provider stores
13519 passwords in plaintext and uses Prosody's configured data storage to store the
13520 authentication data. If you do not trust your server please see
13521 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
13522 about using the hashed backend. See also
13523 @url{http://prosody.im/doc/authentication}
13524 Defaults to @samp{"internal_plain"}.
13527 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
13528 Set logging options. Advanced logging configuration is not yet supported
13529 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
13530 Defaults to @samp{"*syslog"}.
13533 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
13534 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
13535 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
13538 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
13539 A host in Prosody is a domain on which user accounts can be created. For
13540 example if you want your users to have addresses like
13541 @samp{"john.smith@@example.com"} then you need to add a host
13542 @samp{"example.com"}. All options in this list will apply only to this host.
13544 Note: the name "virtual" host is used in configuration to avoid confusion with
13545 the actual physical host that Prosody is installed on. A single Prosody
13546 instance can serve many domains, each one defined as a VirtualHost entry in
13547 Prosody's configuration. Conversely a server that hosts a single domain would
13548 have just one VirtualHost entry.
13550 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
13552 Available @code{virtualhost-configuration} fields are:
13554 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:
13555 @deftypevr {@code{virtualhost-configuration} parameter} string domain
13556 Domain you wish Prosody to serve.
13561 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
13562 Components are extra services on a server which are available to clients,
13563 usually on a subdomain of the main server (such as
13564 @samp{"mycomponent.example.com"}). Example components might be chatroom
13565 servers, user directories, or gateways to other protocols.
13567 Internal components are implemented with Prosody-specific plugins. To add an
13568 internal component, you simply fill the hostname field, and the plugin you wish
13569 to use for the component.
13571 See @url{http://prosody.im/doc/components}.
13572 Defaults to @samp{()}.
13574 Available @code{int-component-configuration} fields are:
13576 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:
13577 @deftypevr {@code{int-component-configuration} parameter} string hostname
13578 Hostname of the component.
13581 @deftypevr {@code{int-component-configuration} parameter} string plugin
13582 Plugin you wish to use for the component.
13585 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
13586 Multi-user chat (MUC) is Prosody's module for allowing you to create
13587 hosted chatrooms/conferences for XMPP users.
13589 General information on setting up and using multi-user chatrooms can be found
13590 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
13591 which you should read if you are new to XMPP chatrooms.
13593 See also @url{http://prosody.im/doc/modules/mod_muc}.
13595 Available @code{mod-muc-configuration} fields are:
13597 @deftypevr {@code{mod-muc-configuration} parameter} string name
13598 The name to return in service discovery responses.
13599 Defaults to @samp{"Prosody Chatrooms"}.
13602 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
13603 If @samp{#t}, this will only allow admins to create new chatrooms.
13604 Otherwise anyone can create a room. The value @samp{"local"} restricts room
13605 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
13606 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
13607 restricts to service administrators only.
13608 Defaults to @samp{#f}.
13611 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
13612 Maximum number of history messages that will be sent to the member that has
13613 just joined the room.
13614 Defaults to @samp{20}.
13621 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13622 External components use XEP-0114, which most standalone components
13623 support. To add an external component, you simply fill the hostname field. See
13624 @url{http://prosody.im/doc/components}.
13625 Defaults to @samp{()}.
13627 Available @code{ext-component-configuration} fields are:
13629 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:
13630 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13631 Password which the component will use to log in.
13634 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13635 Hostname of the component.
13640 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13641 Port(s) Prosody listens on for component connections.
13644 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13645 Interface Prosody listens on for component connections.
13646 Defaults to @samp{"127.0.0.1"}.
13649 It could be that you just want to get a @code{prosody.cfg.lua}
13650 up and running. In that case, you can pass an
13651 @code{opaque-prosody-configuration} record as the value of
13652 @code{prosody-service-type}. As its name indicates, an opaque configuration
13653 does not have easy reflective capabilities.
13654 Available @code{opaque-prosody-configuration} fields are:
13656 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13657 The prosody package.
13660 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13661 The contents of the @code{prosody.cfg.lua} to use.
13664 For example, if your @code{prosody.cfg.lua} is just the empty
13665 string, you could instantiate a prosody service like this:
13668 (service prosody-service-type
13669 (opaque-prosody-configuration
13670 (prosody.cfg.lua "")))
13673 @node Monitoring Services
13674 @subsubsection Monitoring Services
13676 @subsubheading Tailon Service
13678 @uref{https://tailon.readthedocs.io/, Tailon} is a web application for
13679 viewing and searching log files.
13681 The following example will configure the service with default values.
13682 By default, Tailon can be accessed on port 8080 (@code{http://localhost:8080}).
13685 (service tailon-service-type)
13688 The following example customises more of the Tailon configuration,
13689 adding @command{sed} to the list of allowed commands.
13692 (service tailon-service-type
13693 (tailon-configuration
13695 (tailon-configuration-file
13696 (allowed-commands '("tail" "grep" "awk" "sed"))))))
13700 @deftp {Data Type} tailon-configuration
13701 Data type representing the configuration of Tailon.
13702 This type has the following parameters:
13705 @item @code{config-file} (default: @code{(tailon-configuration-file)})
13706 The configuration file to use for Tailon. This can be set to a
13707 @dfn{tailon-configuration-file} record value, or any gexp
13708 (@pxref{G-Expressions}).
13710 For example, to instead use a local file, the @code{local-file} function
13714 (service tailon-service-type
13715 (tailon-configuration
13716 (config-file (local-file "./my-tailon.conf"))))
13719 @item @code{package} (default: @code{tailon})
13720 The tailon package to use.
13725 @deftp {Data Type} tailon-configuration-file
13726 Data type representing the configuration options for Tailon.
13727 This type has the following parameters:
13730 @item @code{files} (default: @code{(list "/var/log")})
13731 List of files to display. The list can include strings for a single file
13732 or directory, or a list, where the first item is the name of a
13733 subsection, and the remaining items are the files or directories in that
13736 @item @code{bind} (default: @code{"localhost:8080"})
13737 Address and port to which Tailon should bind on.
13739 @item @code{relative-root} (default: @code{#f})
13740 URL path to use for Tailon, set to @code{#f} to not use a path.
13742 @item @code{allow-transfers?} (default: @code{#t})
13743 Allow downloading the log files in the web interface.
13745 @item @code{follow-names?} (default: @code{#t})
13746 Allow tailing of not-yet existent files.
13748 @item @code{tail-lines} (default: @code{200})
13749 Number of lines to read initially from each file.
13751 @item @code{allowed-commands} (default: @code{(list "tail" "grep" "awk")})
13752 Commands to allow running. By default, @code{sed} is disabled.
13754 @item @code{debug?} (default: @code{#f})
13755 Set @code{debug?} to @code{#t} to show debug messages.
13761 @node Kerberos Services
13762 @subsubsection Kerberos Services
13765 The @code{(gnu services kerberos)} module provides services relating to
13766 the authentication protocol @dfn{Kerberos}.
13768 @subsubheading Krb5 Service
13770 Programs using a Kerberos client library normally
13771 expect a configuration file in @file{/etc/krb5.conf}.
13772 This service generates such a file from a definition provided in the
13773 operating system declaration.
13774 It does not cause any daemon to be started.
13776 No ``keytab'' files are provided by this service---you must explicitly create them.
13777 This service is known to work with the MIT client library, @code{mit-krb5}.
13778 Other implementations have not been tested.
13780 @defvr {Scheme Variable} krb5-service-type
13781 A service type for Kerberos 5 clients.
13785 Here is an example of its use:
13787 (service krb5-service-type
13788 (krb5-configuration
13789 (default-realm "EXAMPLE.COM")
13790 (allow-weak-crypto? #t)
13793 (name "EXAMPLE.COM")
13794 (admin-server "groucho.example.com")
13795 (kdc "karl.example.com"))
13798 (admin-server "kerb-admin.argrx.edu")
13799 (kdc "keys.argrx.edu"))))))
13803 This example provides a Kerberos@tie{}5 client configuration which:
13805 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13806 of which have distinct administration servers and key distribution centers;
13807 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13808 specified by clients;
13809 @item Accepts services which only support encryption types known to be weak.
13812 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13813 Only the most commonly used ones are described here.
13814 For a full list, and more detailed explanation of each, see the MIT
13815 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13819 @deftp {Data Type} krb5-realm
13820 @cindex realm, kerberos
13823 This field is a string identifying the name of the realm.
13824 A common convention is to use the fully qualified DNS name of your organization,
13825 converted to upper case.
13827 @item @code{admin-server}
13828 This field is a string identifying the host where the administration server is
13832 This field is a string identifying the key distribution center
13837 @deftp {Data Type} krb5-configuration
13840 @item @code{allow-weak-crypto?} (default: @code{#f})
13841 If this flag is @code{#t} then services which only offer encryption algorithms
13842 known to be weak will be accepted.
13844 @item @code{default-realm} (default: @code{#f})
13845 This field should be a string identifying the default Kerberos
13846 realm for the client.
13847 You should set this field to the name of your Kerberos realm.
13848 If this value is @code{#f}
13849 then a realm must be specified with every Kerberos principal when invoking programs
13850 such as @command{kinit}.
13852 @item @code{realms}
13853 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13855 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13861 @subsubheading PAM krb5 Service
13864 The @code{pam-krb5} service allows for login authentication and password
13865 management via Kerberos.
13866 You will need this service if you want PAM enabled applications to authenticate
13867 users using Kerberos.
13869 @defvr {Scheme Variable} pam-krb5-service-type
13870 A service type for the Kerberos 5 PAM module.
13873 @deftp {Data Type} pam-krb5-configuration
13874 Data type representing the configuration of the Kerberos 5 PAM module
13875 This type has the following parameters:
13877 @item @code{pam-krb5} (default: @code{pam-krb5})
13878 The pam-krb5 package to use.
13880 @item @code{minimum-uid} (default: @code{1000})
13881 The smallest user ID for which Kerberos authentications should be attempted.
13882 Local accounts with lower values will silently fail to authenticate.
13888 @subsubsection Web Services
13893 The @code{(gnu services web)} module provides the nginx web server and
13894 also a fastcgi wrapper daemon.
13896 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
13897 [#:log-directory ``/var/log/nginx''] @
13898 [#:run-directory ``/var/run/nginx''] @
13899 [#:server-list '()] @
13900 [#:upstream-list '()] @
13901 [#:config-file @code{#f}]
13903 Return a service that runs @var{nginx}, the nginx web server.
13905 The nginx daemon loads its runtime configuration from @var{config-file}.
13906 Log files are written to @var{log-directory} and temporary runtime data
13907 files are written to @var{run-directory}. For proper operation, these
13908 arguments should match what is in @var{config-file} to ensure that the
13909 directories are created when the service is activated.
13911 As an alternative to using a @var{config-file}, @var{server-list} can be
13912 used to specify the list of @dfn{server blocks} required on the host and
13913 @var{upstream-list} can be used to specify a list of @dfn{upstream
13914 blocks} to configure. For this to work, use the default value for
13917 At startup, @command{nginx} has not yet read its configuration file, so it
13918 uses a default file to log error messages. If it fails to load its
13919 configuration file, that is where error messages are logged. After the
13920 configuration file is loaded, the default error log file changes as per
13921 configuration. In our case, startup error messages can be found in
13922 @file{/var/run/nginx/logs/error.log}, and after configuration in
13923 @file{/var/log/nginx/error.log}. The second location can be changed with the
13924 @var{log-directory} configuration option.
13928 @deffn {Scheme Variable} nginx-service-type
13929 This is type for the nginx web server.
13931 This service can be extended to add server blocks in addition to the
13932 default one, as in this example:
13935 (simple-service 'my-extra-server nginx-service-type
13936 (list (nginx-server-configuration
13938 (root "/srv/http/extra-website"))))
13942 @deftp {Data Type} nginx-server-configuration
13943 Data type representing the configuration of an nginx server block.
13944 This type has the following parameters:
13947 @item @code{http-port} (default: @code{80})
13948 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
13949 nginx should not listen for HTTP (non secure) connection for this
13950 @dfn{server block}.
13952 @item @code{https-port} (default: @code{443})
13953 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
13954 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
13956 Note that nginx can listen for HTTP and HTTPS connections in the same
13957 @dfn{server block}.
13959 @item @code{server-name} (default: @code{(list 'default)})
13960 A list of server names this server represents. @code{'default} represents the
13961 default server for connections matching no other server.
13963 @item @code{root} (default: @code{"/srv/http"})
13964 Root of the website nginx will serve.
13966 @item @code{locations} (default: @code{'()})
13967 A list of @dfn{nginx-location-configuration} or
13968 @dfn{nginx-named-location-configuration} records to use within this
13971 @item @code{index} (default: @code{(list "index.html")})
13972 Index files to look for when clients ask for a directory. If it cannot be found,
13973 Nginx will send the list of files in the directory.
13975 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
13976 Where to find the certificate for secure connections. Set it to @code{#f} if
13977 you don't have a certificate or you don't want to use HTTPS.
13979 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
13980 Where to find the private key for secure connections. Set it to @code{#f} if
13981 you don't have a key or you don't want to use HTTPS.
13983 @item @code{server-tokens?} (default: @code{#f})
13984 Whether the server should add its configuration to response.
13989 @deftp {Data Type} nginx-upstream-configuration
13990 Data type representing the configuration of an nginx @code{upstream}
13991 block. This type has the following parameters:
13995 Name for this group of servers.
13997 @item @code{servers}
13998 Specify the addresses of the servers in the group. The address can be
13999 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
14000 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
14001 prefix @samp{unix:}. For addresses using an IP address or domain name,
14002 the default port is 80, and a different port can be specified
14008 @deftp {Data Type} nginx-location-configuration
14009 Data type representing the configuration of an nginx @code{location}
14010 block. This type has the following parameters:
14014 URI which this location block matches.
14016 @anchor{nginx-location-configuration body}
14018 Body of the location block, specified as a string. This can contain many
14019 configuration directives. For example, to pass requests to a upstream
14020 server group defined using an @code{nginx-upstream-configuration} block,
14021 the following directive would be specified in the body @samp{proxy_pass
14022 http://upstream-name;}.
14027 @deftp {Data Type} nginx-named-location-configuration
14028 Data type representing the configuration of an nginx named location
14029 block. Named location blocks are used for request redirection, and not
14030 used for regular request processing. This type has the following
14035 Name to identify this location block.
14038 @xref{nginx-location-configuration body}, as the body for named location
14039 blocks can be used in a similar way to the
14040 @code{nginx-location-configuration body}. One restriction is that the
14041 body of a named location block cannot contain location blocks.
14048 FastCGI is an interface between the front-end and the back-end of a web
14049 service. It is a somewhat legacy facility; new web services should
14050 generally just talk HTTP between the front-end and the back-end.
14051 However there are a number of back-end services such as PHP or the
14052 optimized HTTP Git repository access that use FastCGI, so we have
14053 support for it in Guix.
14055 To use FastCGI, you configure the front-end web server (e.g., nginx) to
14056 dispatch some subset of its requests to the fastcgi backend, which
14057 listens on a local TCP or UNIX socket. There is an intermediary
14058 @code{fcgiwrap} program that sits between the actual backend process and
14059 the web server. The front-end indicates which backend program to run,
14060 passing that information to the @code{fcgiwrap} process.
14062 @defvr {Scheme Variable} fcgiwrap-service-type
14063 A service type for the @code{fcgiwrap} FastCGI proxy.
14066 @deftp {Data Type} fcgiwrap-configuration
14067 Data type representing the configuration of the @code{fcgiwrap} serice.
14068 This type has the following parameters:
14070 @item @code{package} (default: @code{fcgiwrap})
14071 The fcgiwrap package to use.
14073 @item @code{socket} (default: @code{tcp:127.0.0.1:9000})
14074 The socket on which the @code{fcgiwrap} process should listen, as a
14075 string. Valid @var{socket} values include
14076 @code{unix:@var{/path/to/unix/socket}},
14077 @code{tcp:@var{dot.ted.qu.ad}:@var{port}} and
14078 @code{tcp6:[@var{ipv6_addr}]:port}.
14080 @item @code{user} (default: @code{fcgiwrap})
14081 @itemx @code{group} (default: @code{fcgiwrap})
14082 The user and group names, as strings, under which to run the
14083 @code{fcgiwrap} process. The @code{fastcgi} service will ensure that if
14084 the user asks for the specific user or group names @code{fcgiwrap} that
14085 the corresponding user and/or group is present on the system.
14087 It is possible to configure a FastCGI-backed web service to pass HTTP
14088 authentication information from the front-end to the back-end, and to
14089 allow @code{fcgiwrap} to run the back-end process as a corresponding
14090 local user. To enable this capability on the back-end., run
14091 @code{fcgiwrap} as the @code{root} user and group. Note that this
14092 capability also has to be configured on the front-end as well.
14098 @subsubsection DNS Services
14099 @cindex DNS (domain name system)
14100 @cindex domain name system (DNS)
14102 The @code{(gnu services dns)} module provides services related to the
14103 @dfn{domain name system} (DNS). It provides a server service for hosting
14104 an @emph{authoritative} DNS server for multiple zones, slave or master.
14105 This service uses @uref{https://www.knot-dns.cz/, Knot DNS}.
14107 An example configuration of an authoritative server for two zones, one master
14111 (define-zone-entries example.org.zone
14112 ;; Name TTL Class Type Data
14113 ("@@" "" "IN" "A" "127.0.0.1")
14114 ("@@" "" "IN" "NS" "ns")
14115 ("ns" "" "IN" "A" "127.0.0.1"))
14117 (define master-zone
14118 (knot-zone-configuration
14119 (domain "example.org")
14121 (origin "example.org")
14122 (entries example.org.zone)))))
14125 (knot-zone-configuration
14126 (domain "plop.org")
14127 (dnssec-policy "default")
14128 (master (list "plop-master"))))
14130 (define plop-master
14131 (knot-remote-configuration
14133 (address (list "208.76.58.171"))))
14137 (services (cons* (service knot-service-type
14138 (knot-confifguration
14139 (remotes (list plop-master))
14140 (zones (list master-zone slave-zone))))
14145 @deffn {Scheme Variable} knot-service-type
14146 This is the type for the Knot DNS server.
14148 Knot DNS is an authoritative DNS server, meaning that it can serve multiple
14149 zones, that is to say domain names you would buy from a registrar. This server
14150 is not a resolver, meaning that it can only resolve names for which it is
14151 authoritative. This server can be configured to serve zones as a master server
14152 or a slave server as a per-zone basis. Slave zones will get their data from
14153 masters, and will serve it as an authoritative server. From the point of view
14154 of a resolver, there is no difference between master and slave.
14156 The following data types are used to configure the Knot DNS server:
14159 @deftp {Data Type} knot-key-configuration
14160 Data type representing a key.
14161 This type has the following parameters:
14164 @item @code{id} (default: @code{""})
14165 An identifier for other configuration fields to refer to this key. IDs must
14166 be unique and must not be empty.
14168 @item @code{algorithm} (default: @code{#f})
14169 The algorithm to use. Choose between @code{#f}, @code{'hmac-md5},
14170 @code{'hmac-sha1}, @code{'hmac-sha224}, @code{'hmac-sha256}, @code{'hmac-sha384}
14171 and @code{'hmac-sha512}.
14173 @item @code{secret} (default: @code{""})
14174 The secret key itself.
14179 @deftp {Data Type} knot-acl-configuration
14180 Data type representing an Access Control List (ACL) configuration.
14181 This type has the following parameters:
14184 @item @code{id} (default: @code{""})
14185 An identifier for ether configuration fields to refer to this key. IDs must be
14186 unique and must not be empty.
14188 @item @code{address} (default: @code{'()})
14189 An ordered list of IP addresses, network subnets, or network ranges represented
14190 with strings. The query must match one of them. Empty value means that
14191 address match is not required.
14193 @item @code{key} (default: @code{'()})
14194 An ordered list of references to keys represented with strings. The string
14195 must match a key ID defined in a @code{knot-key-configuration}. No key means
14196 that a key is not require to match that ACL.
14198 @item @code{action} (default: @code{'()})
14199 An ordered list of actions that are permitted or forbidden by this ACL. Possible
14200 values are lists of zero or more elements from @code{'transfer}, @code{'notify}
14201 and @code{'update}.
14203 @item @code{deny?} (default: @code{#f})
14204 When true, the ACL defines restrictions. Listed actions are forbidden. When
14205 false, listed actions are allowed.
14210 @deftp {Data Type} zone-entry
14211 Data type represnting a record entry in a zone file.
14212 This type has the following parameters:
14215 @item @code{name} (default: @code{"@@"})
14216 The name of the record. @code{"@@"} refers to the origin of the zone. Names
14217 are relative to the origin of the zone. For example, in the @code{example.org}
14218 zone, @code{"ns.example.org"} actually refers to @code{ns.example.org.example.org}.
14219 Names ending with a dot are absolute, which means that @code{"ns.example.org."}
14220 refers to @code{ns.example.org}.
14222 @item @code{ttl} (default: @code{""})
14223 The Time-To-Live (TTL) of this record. If not set, the default TTL is used.
14225 @item @code{class} (default: @code{"IN"})
14226 The class of the record. Knot currently supports only @code{"IN"} and
14227 partially @code{"CH"}.
14229 @item @code{type} (default: @code{"A"})
14230 The type of the record. Common types include A (IPv4 address), AAAA (IPv6
14231 address), NS (Name Server) and MX (Mail eXchange). Many other types are
14234 @item @code{data} (default: @code{""})
14235 The data contained in the record. For instance an IP address associated with
14236 an A record, or a domain name associated with an NS record. Remember that
14237 domain names are relative to the origin unless they end with a dot.
14242 @deftp {Data Type} zone-file
14243 Data type representing the content of a zone file.
14244 This type has the following parameters:
14247 @item @code{entries} (default: @code{'()})
14248 The list of entries. The SOA record is taken care of, so you don't need to
14249 put it in the list of entries. This list should probably contain an entry
14250 for your primary authoritative DNS server. Other than using a list of entries
14251 directly, you can use @code{define-zone-entries} to define a object containing
14252 the list of entries more easily, that you can later pass to the @code{entries}
14253 field of the @code{zone-file}.
14255 @item @code{origin} (default: @code{""})
14256 The name of your zone. This parameter cannot be empty.
14258 @item @code{ns} (default: @code{"ns"})
14259 The domain of your primary authoritative DNS server. The name is relative to
14260 the origin, unless it ends with a dot. It is mandatory that this primary
14261 DNS server corresponds to an NS record in the zone and that it is associated
14262 to an IP address in the list of entries.
14264 @item @code{mail} (default: @code{"hostmaster"})
14265 An email address people can contact you at, as the owner of the zone. This
14266 is translated as @code{<mail>@@<origin>}.
14268 @item @code{serial} (default: @code{1})
14269 The serial number of the zone. As this is used to keep track of changes by
14270 both slaves and resolvers, it is mandatory that it @emph{never} decreases.
14271 Always increment it when you make a change in your zone.
14273 @item @code{refresh} (default: @code{(* 2 24 3600)})
14274 The frequency at which slaves will do a zone transfer. This value is a number
14275 of seconds. It can be computed by multiplications or with
14276 @code{(string->duration)}.
14278 @item @code{retry} (default: @code{(* 15 60)})
14279 The period after which a slave will retry to contact its master when it fails
14280 to do so a first time.
14282 @item @code{expiry} (default: @code{(* 14 24 3600)})
14283 Default TTL of records. Existing records are considered correct for at most
14284 this amount of time. After this period, resolvers will invalidate their cache
14285 and check again that it still exists.
14287 @item @code{nx} (default: @code{3600})
14288 Default TTL of inexistant records. This delay is usually short because you want
14289 your new domains to reach everyone quickly.
14294 @deftp {Data Type} knot-remote-configuration
14295 Data type representing a remote configuration.
14296 This type has the following parameters:
14299 @item @code{id} (default: @code{""})
14300 An identifier for other configuration fields to refer to this remote. IDs must
14301 be unique and must not be empty.
14303 @item @code{address} (default: @code{'()})
14304 An ordered list of destination IP addresses. Addresses are tried in sequence.
14305 An optional port can be given with the @@ separator. For instance:
14306 @code{(list "1.2.3.4" "2.3.4.5@@53")}. Default port is 53.
14308 @item @code{via} (default: @code{'()})
14309 An ordered list of source IP addresses. An empty list will have Knot choose
14310 an appropriate source IP. An optional port can be given with the @@ separator.
14311 The default is to choose at random.
14313 @item @code{key} (default: @code{#f})
14314 A reference to a key, that is a string containing the identifier of a key
14315 defined in a @code{knot-key-configuration} field.
14320 @deftp {Data Type} knot-keystore-configuration
14321 Data type representing a keystore to hold dnssec keys.
14322 This type has the following parameters:
14325 @item @code{id} (default: @code{""})
14326 The id of the keystore. It must not be empty.
14328 @item @code{backend} (default: @code{'pem})
14329 The backend to store the keys in. Can be @code{'pem} or @code{'pkcs11}.
14331 @item @code{config} (default: @code{"/var/lib/knot/keys/keys"})
14332 The configuration string of the backend. An example for the PKCS#11 is:
14333 @code{"pkcs11:token=knot;pin-value=1234 /gnu/store/.../lib/pkcs11/libsofthsm2.so"}.
14334 For the pem backend, the string reprensents a path in the filesystem.
14339 @deftp {Data Type} knot-policy-configuration
14340 Data type representing a dnssec policy. Knot DNS is able to automatically
14341 sign your zones. It can either generate and manage your keys automatically or
14342 use keys that you generate.
14344 Dnssec is usually implemented using two keys: a Key Signing Key (KSK) that is
14345 used to sign the second, and a Zone Signing Key (ZSK) that is used to sign the
14346 zone. In order to be trusted, the KSK needs to be present in the parent zone
14347 (usually a top-level domain). If your registrar supports dnssec, you will
14348 have to send them your KSK's hash so they can add a DS record in their zone.
14349 This is not automated and need to be done each time you change your KSK.
14351 The policy also defines the lifetime of keys. Usually, ZSK can be changed
14352 easily and use weaker cryptographic functions (they use lower parameters) in
14353 order to sign records quickly, so they are changed often. The KSK however
14354 requires manual interaction with the registrar, so they are changed less often
14355 and use stronger parameters because they sign only one record.
14357 This type has the following parameters:
14360 @item @code{id} (default: @code{""})
14361 The id of the policy. It must not be empty.
14363 @item @code{keystore} (default: @code{"default"})
14364 A reference to a keystore, that is a string containing the identifier of a
14365 keystore defined in a @code{knot-keystore-configuration} field. The
14366 @code{"default"} identifier means the default keystore (a kasp database that
14367 was setup by this service).
14369 @item @code{manual?} (default: @code{#f})
14370 Whether the key management is manual or automatic.
14372 @item @code{single-type-signing?} (default: @code{#f})
14373 When @code{#t}, use the Single-Type Signing Scheme.
14375 @item @code{algorithm} (default: @code{"ecdsap256sha256"})
14376 An algorithm of signing keys and issued signatures.
14378 @item @code{ksk-size} (default: @code{256})
14379 The length of the KSK. Note that this value is correct for the default
14380 algorithm, but would be unsecure for other algorithms.
14382 @item @code{zsk-size} (default: @code{256})
14383 The length of the ZSK. Note that this value is correct for the default
14384 algorithm, but would be unsecure for other algorithms.
14386 @item @code{dnskey-ttl} (default: @code{'default})
14387 The TTL value for DNSKEY records added into zone apex. The special
14388 @code{'default} value means same as the zone SOA TTL.
14390 @item @code{zsk-lifetime} (default: @code{(* 30 24 3600)})
14391 The period between ZSK publication and the next rollover initiation.
14393 @item @code{propagation-delay} (default: @code{(* 24 3600)})
14394 An extra delay added for each key rollover step. This value should be high
14395 enough to cover propagation of data from the master server to all slaves.
14397 @item @code{rrsig-lifetime} (default: @code{(* 14 24 3600)})
14398 A validity period of newly issued signatures.
14400 @item @code{rrsig-refresh} (default: @code{(* 7 24 3600)})
14401 A period how long before a signature expiration the signature will be refreshed.
14403 @item @code{nsec3?} (default: @code{#f})
14404 When @code{#t}, NSEC3 will be used instead of NSEC.
14406 @item @code{nsec3-iterations} (default: @code{5})
14407 The number of additional times the hashing is performed.
14409 @item @code{nsec3-salt-length} (default: @code{8})
14410 The length of a salt field in octets, which is appended to the original owner
14411 name before hashing.
14413 @item @code{nsec3-salt-lifetime} (default: @code{(* 30 24 3600)})
14414 The validity period of newly issued salt field.
14419 @deftp {Data Type} knot-zone-configuration
14420 Data type representing a zone served by Knot.
14421 This type has the following parameters:
14424 @item @code{domain} (default: @code{""})
14425 The domain served by this configuration. It must not be empty.
14427 @item @code{file} (default: @code{""})
14428 The file where this zone is saved. This parameter is ignored by master zones.
14429 Empty means default location that depends on the domain name.
14431 @item @code{zone} (default: @code{(zone-file)})
14432 The content of the zone file. This parameter is ignored by slave zones. It
14433 must contain a zone-file record.
14435 @item @code{master} (default: @code{'()})
14436 A list of master remotes. When empty, this zone is a master. When set, this
14437 zone is a slave. This is a list of remotes identifiers.
14439 @item @code{ddns-master} (default: @code{#f})
14440 The main master. When empty, it defaults to the first master in the list of
14443 @item @code{notify} (default: @code{'()})
14444 A list of slave remote identifiers.
14446 @item @code{acl} (default: @code{'()})
14447 A list of acl identifiers.
14449 @item @code{semantic-checks?} (default: @code{#f})
14450 When set, this adds more semantic checks to the zone.
14452 @item @code{disable-any?} (default: @code{#f})
14453 When set, this forbids queries of the ANY type.
14455 @item @code{zonefile-sync} (default: @code{0})
14456 The delay between a modification in memory and on disk. 0 means immediate
14459 @item @code{serial-policy} (default: @code{'increment})
14460 A policy between @code{'increment} and @code{'unixtime}.
14465 @deftp {Data Type} knot-configuration
14466 Data type representing the Knot configuration.
14467 This type has the following parameters:
14470 @item @code{knot} (default: @code{knot})
14473 @item @code{run-directory} (default: @code{"/var/run/knot"})
14474 The run directory. This directory will be used for pid file and sockets.
14476 @item @code{listen-v4} (default: @code{"0.0.0.0"})
14477 An ip address on which to listen.
14479 @item @code{listen-v6} (default: @code{"::"})
14480 An ip address on which to listen.
14482 @item @code{listen-port} (default: @code{53})
14483 A port on which to listen.
14485 @item @code{keys} (default: @code{'()})
14486 The list of knot-key-configuration used by this configuration.
14488 @item @code{acls} (default: @code{'()})
14489 The list of knot-acl-configuration used by this configuration.
14491 @item @code{remotes} (default: @code{'()})
14492 The list of knot-remote-configuration used by this configuration.
14494 @item @code{zones} (default: @code{'()})
14495 The list of knot-zone-configuration used by this configuration.
14501 @subsubsection VPN Services
14502 @cindex VPN (virtual private network)
14503 @cindex virtual private network (VPN)
14505 The @code{(gnu services vpn)} module provides services related to
14506 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
14507 your machine to connect to a VPN, and a @emph{servire} service for your machine
14508 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
14510 @deffn {Scheme Procedure} openvpn-client-service @
14511 [#:config (openvpn-client-configuration)]
14513 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
14516 @deffn {Scheme Procedure} openvpn-server-service @
14517 [#:config (openvpn-server-configuration)]
14519 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
14521 Both can be run simultaneously.
14524 @c %automatically generated documentation
14526 Available @code{openvpn-client-configuration} fields are:
14528 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
14529 The OpenVPN package.
14533 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
14534 The OpenVPN pid file.
14536 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14540 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
14541 The protocol (UDP or TCP) used to open a channel between clients and
14544 Defaults to @samp{udp}.
14548 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
14549 The device type used to represent the VPN connection.
14551 Defaults to @samp{tun}.
14555 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
14556 The certificate authority to check connections against.
14558 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14562 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
14563 The certificate of the machine the daemon is running on. It should be
14564 signed by the authority given in @code{ca}.
14566 Defaults to @samp{"/etc/openvpn/client.crt"}.
14570 @deftypevr {@code{openvpn-client-configuration} parameter} string key
14571 The key of the machine the daemon is running on. It must be the key whose
14572 certificate is @code{cert}.
14574 Defaults to @samp{"/etc/openvpn/client.key"}.
14578 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
14579 Whether to use the lzo compression algorithm.
14581 Defaults to @samp{#t}.
14585 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
14586 Don't re-read key files across SIGUSR1 or --ping-restart.
14588 Defaults to @samp{#t}.
14592 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
14593 Don't close and reopen TUN/TAP device or run up/down scripts across
14594 SIGUSR1 or --ping-restart restarts.
14596 Defaults to @samp{#t}.
14600 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
14603 Defaults to @samp{3}.
14607 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
14608 Add an additional layer of HMAC authentication on top of the TLS control
14609 channel to protect against DoS attacks.
14611 Defaults to @samp{#f}.
14615 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
14616 Whether to check the server certificate has server usage extension.
14618 Defaults to @samp{#t}.
14622 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
14623 Bind to a specific local port number.
14625 Defaults to @samp{#f}.
14629 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
14630 Retry resolving server address.
14632 Defaults to @samp{#t}.
14636 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
14637 A list of remote servers to connect to.
14639 Defaults to @samp{()}.
14641 Available @code{openvpn-remote-configuration} fields are:
14643 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
14646 Defaults to @samp{"my-server"}.
14650 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
14651 Port number the server listens to.
14653 Defaults to @samp{1194}.
14658 @c %end of automatic openvpn-client documentation
14660 @c %automatically generated documentation
14662 Available @code{openvpn-server-configuration} fields are:
14664 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
14665 The OpenVPN package.
14669 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
14670 The OpenVPN pid file.
14672 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14676 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
14677 The protocol (UDP or TCP) used to open a channel between clients and
14680 Defaults to @samp{udp}.
14684 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
14685 The device type used to represent the VPN connection.
14687 Defaults to @samp{tun}.
14691 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
14692 The certificate authority to check connections against.
14694 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14698 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
14699 The certificate of the machine the daemon is running on. It should be
14700 signed by the authority given in @code{ca}.
14702 Defaults to @samp{"/etc/openvpn/client.crt"}.
14706 @deftypevr {@code{openvpn-server-configuration} parameter} string key
14707 The key of the machine the daemon is running on. It must be the key whose
14708 certificate is @code{cert}.
14710 Defaults to @samp{"/etc/openvpn/client.key"}.
14714 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
14715 Whether to use the lzo compression algorithm.
14717 Defaults to @samp{#t}.
14721 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
14722 Don't re-read key files across SIGUSR1 or --ping-restart.
14724 Defaults to @samp{#t}.
14728 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
14729 Don't close and reopen TUN/TAP device or run up/down scripts across
14730 SIGUSR1 or --ping-restart restarts.
14732 Defaults to @samp{#t}.
14736 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
14739 Defaults to @samp{3}.
14743 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
14744 Add an additional layer of HMAC authentication on top of the TLS control
14745 channel to protect against DoS attacks.
14747 Defaults to @samp{#f}.
14751 @deftypevr {@code{openvpn-server-configuration} parameter} number port
14752 Specifies the port number on which the server listens.
14754 Defaults to @samp{1194}.
14758 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
14759 An ip and mask specifying the subnet inside the virtual network.
14761 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
14765 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
14766 A CIDR notation specifying the IPv6 subnet inside the virtual network.
14768 Defaults to @samp{#f}.
14772 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
14773 The Diffie-Hellman parameters file.
14775 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
14779 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
14780 The file that records client IPs.
14782 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
14786 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
14787 When true, the server will act as a gateway for its clients.
14789 Defaults to @samp{#f}.
14793 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
14794 When true, clients are allowed to talk to each other inside the VPN.
14796 Defaults to @samp{#f}.
14800 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
14801 Causes ping-like messages to be sent back and forth over the link so
14802 that each side knows when the other side has gone down. @code{keepalive}
14803 requires a pair. The first element is the period of the ping sending,
14804 and the second element is the timeout before considering the other side
14809 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
14810 The maximum number of clients.
14812 Defaults to @samp{100}.
14816 @deftypevr {@code{openvpn-server-configuration} parameter} string status
14817 The status file. This file shows a small report on current connection.
14818 It is truncated and rewritten every minute.
14820 Defaults to @samp{"/var/run/openvpn/status"}.
14824 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
14825 The list of configuration for some clients.
14827 Defaults to @samp{()}.
14829 Available @code{openvpn-ccd-configuration} fields are:
14831 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
14834 Defaults to @samp{"client"}.
14838 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
14841 Defaults to @samp{#f}.
14845 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
14848 Defaults to @samp{#f}.
14855 @c %end of automatic openvpn-server documentation
14858 @node Network File System
14859 @subsubsection Network File System
14862 The @code{(gnu services nfs)} module provides the following services,
14863 which are most commonly used in relation to mounting or exporting
14864 directory trees as @dfn{network file systems} (NFS).
14866 @subsubheading RPC Bind Service
14869 The RPC Bind service provides a facility to map program numbers into
14870 universal addresses.
14871 Many NFS related services use this facility. Hence it is automatically
14872 started when a dependent service starts.
14874 @defvr {Scheme Variable} rpcbind-service-type
14875 A service type for the RPC portmapper daemon.
14879 @deftp {Data Type} rpcbind-configuration
14880 Data type representing the configuration of the RPC Bind Service.
14881 This type has the following parameters:
14883 @item @code{rpcbind} (default: @code{rpcbind})
14884 The rpcbind package to use.
14886 @item @code{warm-start?} (default: @code{#t})
14887 If this parameter is @code{#t}, then the daemon will read a
14888 state file on startup thus reloading state information saved by a previous
14894 @subsubheading Pipefs Pseudo File System
14898 The pipefs file system is used to transfer NFS related data
14899 between the kernel and user space programs.
14901 @defvr {Scheme Variable} pipefs-service-type
14902 A service type for the pipefs pseudo file system.
14905 @deftp {Data Type} pipefs-configuration
14906 Data type representing the configuration of the pipefs pseudo file system service.
14907 This type has the following parameters:
14909 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14910 The directory to which the file system is to be attached.
14915 @subsubheading GSS Daemon Service
14918 @cindex global security system
14920 The @dfn{global security system} (GSS) daemon provides strong security for RPC
14922 Before exchanging RPC requests an RPC client must establish a security
14923 context. Typically this is done using the Kerberos command @command{kinit}
14924 or automatically at login time using PAM services (@pxref{Kerberos Services}).
14926 @defvr {Scheme Variable} gss-service-type
14927 A service type for the Global Security System (GSS) daemon.
14930 @deftp {Data Type} gss-configuration
14931 Data type representing the configuration of the GSS daemon service.
14932 This type has the following parameters:
14934 @item @code{nfs-utils} (default: @code{nfs-utils})
14935 The package in which the @command{rpc.gssd} command is to be found.
14937 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14938 The directory where the pipefs file system is mounted.
14944 @subsubheading IDMAP Daemon Service
14946 @cindex name mapper
14948 The idmap daemon service provides mapping between user IDs and user names.
14949 Typically it is required in order to access file systems mounted via NFSv4.
14951 @defvr {Scheme Variable} idmap-service-type
14952 A service type for the Identity Mapper (IDMAP) daemon.
14955 @deftp {Data Type} idmap-configuration
14956 Data type representing the configuration of the IDMAP daemon service.
14957 This type has the following parameters:
14959 @item @code{nfs-utils} (default: @code{nfs-utils})
14960 The package in which the @command{rpc.idmapd} command is to be found.
14962 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14963 The directory where the pipefs file system is mounted.
14965 @item @code{domain} (default: @code{#f})
14966 The local NFSv4 domain name.
14967 This must be a string or @code{#f}.
14968 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
14973 @node Continuous Integration
14974 @subsubsection Continuous Integration
14976 @cindex continuous integration
14977 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
14978 integration tool for Guix. It can be used both for development and for
14979 providing substitutes to others (@pxref{Substitutes}).
14981 The @code{(gnu services cuirass)} module provides the following service.
14983 @defvr {Scheme Procedure} cuirass-service-type
14984 The type of the Cuirass service. Its value must be a
14985 @code{cuirass-configuration} object, as described below.
14988 To add build jobs, you have to set the @code{specifications} field of
14989 the configuration. Here is an example of a service defining a build job
14990 based on a specification that can be found in Cuirass source tree. This
14991 service polls the Guix repository and builds a subset of the Guix
14992 packages, as prescribed in the @file{gnu-system.scm} example spec:
14995 (let ((spec #~((#:name . "guix")
14996 (#:url . "git://git.savannah.gnu.org/guix.git")
14997 (#:load-path . ".")
14999 ;; Here we must provide an absolute file name.
15000 ;; We take jobs from one of the examples provided
15002 (#:file . #$(file-append
15004 "/tests/gnu-system.scm"))
15006 (#:proc . hydra-jobs)
15007 (#:arguments (subset . "hello"))
15008 (#:branch . "master"))))
15009 (service cuirass-service-type
15010 (cuirass-configuration
15011 (specifications #~(list #$spec)))))
15014 While information related to build jobs is located directly in the
15015 specifications, global settings for the @command{cuirass} process are
15016 accessible in other @code{cuirass-configuration} fields.
15018 @deftp {Data Type} cuirass-configuration
15019 Data type representing the configuration of Cuirass.
15022 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
15023 Location of the log file.
15025 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
15026 Location of the repository cache.
15028 @item @code{user} (default: @code{"cuirass"})
15029 Owner of the @code{cuirass} process.
15031 @item @code{group} (default: @code{"cuirass"})
15032 Owner's group of the @code{cuirass} process.
15034 @item @code{interval} (default: @code{60})
15035 Number of seconds between the poll of the repositories followed by the
15038 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
15039 Location of sqlite database which contains the build results and previously
15040 added specifications.
15042 @item @code{port} (default: @code{8080})
15043 Port number used by the HTTP server.
15045 @item @code{specifications} (default: @code{#~'()})
15046 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
15047 where a specification is an association list
15048 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
15049 keys are keywords (@code{#:keyword-example}) as shown in the example
15052 @item @code{use-substitutes?} (default: @code{#f})
15053 This allows using substitutes to avoid building every dependencies of a job
15056 @item @code{one-shot?} (default: @code{#f})
15057 Only evaluate specifications and build derivations once.
15059 @item @code{fallback?} (default: @code{#f})
15060 When substituting a pre-built binary fails, fall back to building
15063 @item @code{load-path} (default: @code{'()})
15064 This allows users to define their own packages and make them visible to
15065 cuirass as in @command{guix build} command.
15067 @item @code{cuirass} (default: @code{cuirass})
15068 The Cuirass package to use.
15072 @node Power management Services
15073 @subsubsection Power management Services
15075 @cindex power management with TLP
15076 The @code{(gnu services pm)} module provides a Guix service definition
15077 for the Linux power management tool TLP.
15079 TLP enables various powersaving modes in userspace and kernel.
15080 Contrary to @code{upower-service}, it is not a passive,
15081 monitoring tool, as it will apply custom settings each time a new power
15082 source is detected. More information can be found at
15083 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
15085 @deffn {Scheme Variable} tlp-service-type
15086 The service type for the TLP tool. Its value should be a valid
15087 TLP configuration (see below). To use the default settings, simply
15090 (service tlp-service-type)
15094 By default TLP does not need much configuration but most TLP parameters
15095 can be tweaked using @code{tlp-configuration}.
15097 Each parameter definition is preceded by its type; for example,
15098 @samp{boolean foo} indicates that the @code{foo} parameter
15099 should be specified as a boolean. Types starting with
15100 @code{maybe-} denote parameters that won't show up in TLP config file
15101 when their value is @code{'disabled}.
15103 @c The following documentation was initially generated by
15104 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
15105 @c documentation is better, so we shouldn't hesitate to edit below as
15106 @c needed. However if the change you want to make to this documentation
15107 @c can be done in an automated way, it's probably easier to change
15108 @c (generate-documentation) than to make it below and have to deal with
15109 @c the churn as TLP updates.
15111 Available @code{tlp-configuration} fields are:
15113 @deftypevr {@code{tlp-configuration} parameter} package tlp
15118 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
15119 Set to true if you wish to enable TLP.
15121 Defaults to @samp{#t}.
15125 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
15126 Default mode when no power supply can be detected. Alternatives are AC
15129 Defaults to @samp{"AC"}.
15133 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
15134 Number of seconds Linux kernel has to wait after the disk goes idle,
15135 before syncing on AC.
15137 Defaults to @samp{0}.
15141 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
15142 Same as @code{disk-idle-ac} but on BAT mode.
15144 Defaults to @samp{2}.
15148 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
15149 Dirty pages flushing periodicity, expressed in seconds.
15151 Defaults to @samp{15}.
15155 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
15156 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
15158 Defaults to @samp{60}.
15162 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
15163 CPU frequency scaling governor on AC mode. With intel_pstate driver,
15164 alternatives are powersave and performance. With acpi-cpufreq driver,
15165 alternatives are ondemand, powersave, performance and conservative.
15167 Defaults to @samp{disabled}.
15171 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
15172 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
15174 Defaults to @samp{disabled}.
15178 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
15179 Set the min available frequency for the scaling governor on AC.
15181 Defaults to @samp{disabled}.
15185 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
15186 Set the max available frequency for the scaling governor on AC.
15188 Defaults to @samp{disabled}.
15192 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
15193 Set the min available frequency for the scaling governor on BAT.
15195 Defaults to @samp{disabled}.
15199 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
15200 Set the max available frequency for the scaling governor on BAT.
15202 Defaults to @samp{disabled}.
15206 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
15207 Limit the min P-state to control the power dissipation of the CPU, in AC
15208 mode. Values are stated as a percentage of the available performance.
15210 Defaults to @samp{disabled}.
15214 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
15215 Limit the max P-state to control the power dissipation of the CPU, in AC
15216 mode. Values are stated as a percentage of the available performance.
15218 Defaults to @samp{disabled}.
15222 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
15223 Same as @code{cpu-min-perf-on-ac} on BAT mode.
15225 Defaults to @samp{disabled}.
15229 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
15230 Same as @code{cpu-max-perf-on-ac} on BAT mode.
15232 Defaults to @samp{disabled}.
15236 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
15237 Enable CPU turbo boost feature on AC mode.
15239 Defaults to @samp{disabled}.
15243 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
15244 Same as @code{cpu-boost-on-ac?} on BAT mode.
15246 Defaults to @samp{disabled}.
15250 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
15251 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
15252 used under light load conditions.
15254 Defaults to @samp{#f}.
15258 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
15259 Same as @code{sched-powersave-on-ac?} but on BAT mode.
15261 Defaults to @samp{#t}.
15265 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
15266 Enable Linux kernel NMI watchdog.
15268 Defaults to @samp{#f}.
15272 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
15273 For Linux kernels with PHC patch applied, change CPU voltages. An
15274 example value would be @samp{"F:V F:V F:V F:V"}.
15276 Defaults to @samp{disabled}.
15280 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
15281 Set CPU performance versus energy saving policy on AC. Alternatives are
15282 performance, normal, powersave.
15284 Defaults to @samp{"performance"}.
15288 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
15289 Same as @code{energy-perf-policy-ac} but on BAT mode.
15291 Defaults to @samp{"powersave"}.
15295 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
15300 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
15301 Hard disk advanced power management level.
15305 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
15306 Same as @code{disk-apm-bat} but on BAT mode.
15310 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
15311 Hard disk spin down timeout. One value has to be specified for each
15312 declared hard disk.
15314 Defaults to @samp{disabled}.
15318 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
15319 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
15321 Defaults to @samp{disabled}.
15325 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
15326 Select IO scheduler for disk devices. One value has to be specified for
15327 each declared hard disk. Example alternatives are cfq, deadline and
15330 Defaults to @samp{disabled}.
15334 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
15335 SATA aggressive link power management (ALPM) level. Alternatives are
15336 min_power, medium_power, max_performance.
15338 Defaults to @samp{"max_performance"}.
15342 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
15343 Same as @code{sata-linkpwr-ac} but on BAT mode.
15345 Defaults to @samp{"min_power"}.
15349 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
15350 Exclude specified SATA host devices for link power management.
15352 Defaults to @samp{disabled}.
15356 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
15357 Enable Runtime Power Management for AHCI controller and disks on AC
15360 Defaults to @samp{disabled}.
15364 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
15365 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
15367 Defaults to @samp{disabled}.
15371 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
15372 Seconds of inactivity before disk is suspended.
15374 Defaults to @samp{15}.
15378 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
15379 PCI Express Active State Power Management level. Alternatives are
15380 default, performance, powersave.
15382 Defaults to @samp{"performance"}.
15386 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
15387 Same as @code{pcie-aspm-ac} but on BAT mode.
15389 Defaults to @samp{"powersave"}.
15393 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
15394 Radeon graphics clock speed level. Alternatives are low, mid, high,
15397 Defaults to @samp{"high"}.
15401 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
15402 Same as @code{radeon-power-ac} but on BAT mode.
15404 Defaults to @samp{"low"}.
15408 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
15409 Radeon dynamic power management method (DPM). Alternatives are battery,
15412 Defaults to @samp{"performance"}.
15416 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
15417 Same as @code{radeon-dpm-state-ac} but on BAT mode.
15419 Defaults to @samp{"battery"}.
15423 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
15424 Radeon DPM performance level. Alternatives are auto, low, high.
15426 Defaults to @samp{"auto"}.
15430 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
15431 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
15433 Defaults to @samp{"auto"}.
15437 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
15438 Wifi power saving mode.
15440 Defaults to @samp{#f}.
15444 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
15445 Same as @code{wifi-power-ac?} but on BAT mode.
15447 Defaults to @samp{#t}.
15451 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
15452 Disable wake on LAN.
15454 Defaults to @samp{#t}.
15458 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
15459 Timeout duration in seconds before activating audio power saving on
15460 Intel HDA and AC97 devices. A value of 0 disables power saving.
15462 Defaults to @samp{0}.
15466 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
15467 Same as @code{sound-powersave-ac} but on BAT mode.
15469 Defaults to @samp{1}.
15473 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
15474 Disable controller in powersaving mode on Intel HDA devices.
15476 Defaults to @samp{#t}.
15480 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
15481 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
15482 powered on again by releasing (and reinserting) the eject lever or by
15483 pressing the disc eject button on newer models.
15485 Defaults to @samp{#f}.
15489 @deftypevr {@code{tlp-configuration} parameter} string bay-device
15490 Name of the optical drive device to power off.
15492 Defaults to @samp{"sr0"}.
15496 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
15497 Runtime Power Management for PCI(e) bus devices. Alternatives are on
15500 Defaults to @samp{"on"}.
15504 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
15505 Same as @code{runtime-pm-ac} but on BAT mode.
15507 Defaults to @samp{"auto"}.
15511 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
15512 Runtime Power Management for all PCI(e) bus devices, except blacklisted
15515 Defaults to @samp{#t}.
15519 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
15520 Exclude specified PCI(e) device addresses from Runtime Power Management.
15522 Defaults to @samp{disabled}.
15526 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
15527 Exclude PCI(e) devices assigned to the specified drivers from Runtime
15532 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
15533 Enable USB autosuspend feature.
15535 Defaults to @samp{#t}.
15539 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
15540 Exclude specified devices from USB autosuspend.
15542 Defaults to @samp{disabled}.
15546 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
15547 Exclude WWAN devices from USB autosuspend.
15549 Defaults to @samp{#t}.
15553 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
15554 Include specified devices into USB autosuspend, even if they are already
15555 excluded by the driver or via @code{usb-blacklist-wwan?}.
15557 Defaults to @samp{disabled}.
15561 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
15562 Enable USB autosuspend before shutdown.
15564 Defaults to @samp{disabled}.
15568 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
15569 Restore radio device state (bluetooth, wifi, wwan) from previous
15570 shutdown on system startup.
15572 Defaults to @samp{#f}.
15577 The @code{(gnu services pm)} module provides an interface to
15578 thermald, a CPU frequency scaling service which helps prevent overheating.
15580 @defvr {Scheme Variable} thermald-service-type
15581 This is the service type for
15582 @uref{https://01.org/linux-thermal-daemon/, thermald}, the Linux
15583 Thermal Daemon, which is responsible for controlling the thermal state
15584 of processors and preventing overheating.
15587 @deftp {Data Type} thermald-configuration
15588 Data type representing the configuration of @code{thermald-service-type}.
15591 @item @code{ignore-cpuid-check?} (default: @code{#f})
15592 Ignore cpuid check for supported CPU models.
15594 @item @code{thermald} (default: @var{thermald})
15595 Package object of thermald.
15601 @node Miscellaneous Services
15602 @subsubsection Miscellaneous Services
15605 @subsubheading System Control Service
15607 The @code{(gnu services sysctl)} provides a service to configure kernel
15608 parameters at boot.
15610 @defvr {Scheme Variable} sysctl-service-type
15611 The service type for @command{sysctl}, which modifies kernel parameters
15612 under @file{/proc/sys/}. To enable IPv4 forwarding, it can be
15616 (service sysctl-service-type
15617 (sysctl-configuration
15618 (settings '(("net.ipv4.ip_forward" . "1")))))
15622 @deftp {Data Type} sysctl-configuration
15623 The data type representing the configuration of @command{sysctl}.
15626 @item @code{sysctl} (default: @code{(file-append procps "/sbin/sysctl"})
15627 The @command{sysctl} executable to use.
15629 @item @code{settings} (default: @code{'()})
15630 An association list specifies kernel parameters and their values.
15635 @subsubheading Lirc Service
15637 The @code{(gnu services lirc)} module provides the following service.
15639 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
15640 [#:device #f] [#:driver #f] [#:config-file #f] @
15641 [#:extra-options '()]
15642 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
15643 decodes infrared signals from remote controls.
15645 Optionally, @var{device}, @var{driver} and @var{config-file}
15646 (configuration file name) may be specified. See @command{lircd} manual
15649 Finally, @var{extra-options} is a list of additional command-line options
15650 passed to @command{lircd}.
15654 @subsubheading Spice Service
15656 The @code{(gnu services spice)} module provides the following service.
15658 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
15659 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
15660 that enables sharing the clipboard with a vm and setting the guest display
15661 resolution when the graphical console window resizes.
15664 @subsubsection Dictionary Services
15666 The @code{(gnu services dict)} module provides the following service:
15668 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
15669 Return a service that runs the @command{dicod} daemon, an implementation
15670 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
15672 The optional @var{config} argument specifies the configuration for
15673 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
15674 default it serves the GNU Collaborative International Dictonary of English.
15676 You can add @command{open localhost} to your @file{~/.dico} file to make
15677 @code{localhost} the default server for @command{dico} client
15678 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
15681 @deftp {Data Type} dicod-configuration
15682 Data type representing the configuration of dicod.
15685 @item @code{dico} (default: @var{dico})
15686 Package object of the GNU Dico dictionary server.
15688 @item @code{interfaces} (default: @var{'("localhost")})
15689 This is the list of IP addresses and ports and possibly socket file
15690 names to listen to (@pxref{Server Settings, @code{listen} directive,,
15691 dico, GNU Dico Manual}).
15693 @item @code{handlers} (default: @var{'()})
15694 List of @code{<dicod-handler>} objects denoting handlers (module instances).
15696 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
15697 List of @code{<dicod-database>} objects denoting dictionaries to be served.
15701 @deftp {Data Type} dicod-handler
15702 Data type representing a dictionary handler (module instance).
15706 Name of the handler (module instance).
15708 @item @code{module} (default: @var{#f})
15709 Name of the dicod module of the handler (instance). If it is @code{#f},
15710 the module has the same name as the handler.
15711 (@pxref{Modules,,, dico, GNU Dico Manual}).
15713 @item @code{options}
15714 List of strings or gexps representing the arguments for the module handler
15718 @deftp {Data Type} dicod-database
15719 Data type representing a dictionary database.
15723 Name of the database, will be used in DICT commands.
15725 @item @code{handler}
15726 Name of the dicod handler (module instance) used by this database
15727 (@pxref{Handlers,,, dico, GNU Dico Manual}).
15729 @item @code{complex?} (default: @var{#f})
15730 Whether the database configuration complex. The complex configuration
15731 will need a corresponding @code{<dicod-handler>} object, otherwise not.
15733 @item @code{options}
15734 List of strings or gexps representing the arguments for the database
15735 (@pxref{Databases,,, dico, GNU Dico Manual}).
15739 @defvr {Scheme Variable} %dicod-database:gcide
15740 A @code{<dicod-database>} object serving the GNU Collaborative International
15741 Dictionary of English using the @code{gcide} package.
15744 The following is an example @code{dicod-service} configuration.
15747 (dicod-service #:config
15748 (dicod-configuration
15749 (handlers (list (dicod-handler
15753 (list #~(string-append "dbdir=" #$wordnet))))))
15754 (databases (list (dicod-database
15757 (handler "wordnet")
15758 (options '("database=wn")))
15759 %dicod-database:gcide))))
15762 @subsubsection Version Control
15764 The @code{(gnu services version-control)} module provides the following services:
15766 @subsubheading Git daemon service
15768 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
15770 Return a service that runs @command{git daemon}, a simple TCP server to
15771 expose repositories over the Git protocol for anonymous access.
15773 The optional @var{config} argument should be a
15774 @code{<git-daemon-configuration>} object, by default it allows read-only
15775 access to exported@footnote{By creating the magic file
15776 "git-daemon-export-ok" in the repository directory.} repositories under
15781 @deftp {Data Type} git-daemon-configuration
15782 Data type representing the configuration for @code{git-daemon-service}.
15785 @item @code{package} (default: @var{git})
15786 Package object of the Git distributed version control system.
15788 @item @code{export-all?} (default: @var{#f})
15789 Whether to allow access for all Git repositories, even if they do not
15790 have the @file{git-daemon-export-ok} file.
15792 @item @code{base-path} (default: @file{/srv/git})
15793 Whether to remap all the path requests as relative to the given path.
15794 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
15795 then if you later try to pull @code{git://example.com/hello.git}, git
15796 daemon will interpret the path as @code{/srv/git/hello.git}.
15798 @item @code{user-path} (default: @var{#f})
15799 Whether to allow @code{~user} notation to be used in requests. When
15800 specified with empty string, requests to @code{git://host/~alice/foo} is
15801 taken as a request to access @code{foo} repository in the home directory
15802 of user @code{alice}. If @var{(user-path "path")} is specified, the
15803 same request is taken as a request to access @code{path/foo} repository
15804 in the home directory of user @code{alice}.
15806 @item @code{listen} (default: @var{'()})
15807 Whether to listen on specific IP addresses or hostnames, defaults to
15810 @item @code{port} (default: @var{#f})
15811 Whether to listen on an alternative port, which defaults to 9418.
15813 @item @code{whitelist} (default: @var{'()})
15814 If not empty, only allow access to this list of directories.
15816 @item @code{extra-options} (default: @var{'()})
15817 Extra options will be passed to @code{git daemon}, please run
15818 @command{man git-daemon} for more information.
15823 @node Setuid Programs
15824 @subsection Setuid Programs
15826 @cindex setuid programs
15827 Some programs need to run with ``root'' privileges, even when they are
15828 launched by unprivileged users. A notorious example is the
15829 @command{passwd} program, which users can run to change their
15830 password, and which needs to access the @file{/etc/passwd} and
15831 @file{/etc/shadow} files---something normally restricted to root, for
15832 obvious security reasons. To address that, these executables are
15833 @dfn{setuid-root}, meaning that they always run with root privileges
15834 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
15835 for more info about the setuid mechanism.)
15837 The store itself @emph{cannot} contain setuid programs: that would be a
15838 security issue since any user on the system can write derivations that
15839 populate the store (@pxref{The Store}). Thus, a different mechanism is
15840 used: instead of changing the setuid bit directly on files that are in
15841 the store, we let the system administrator @emph{declare} which programs
15842 should be setuid root.
15844 The @code{setuid-programs} field of an @code{operating-system}
15845 declaration contains a list of G-expressions denoting the names of
15846 programs to be setuid-root (@pxref{Using the Configuration System}).
15847 For instance, the @command{passwd} program, which is part of the Shadow
15848 package, can be designated by this G-expression (@pxref{G-Expressions}):
15851 #~(string-append #$shadow "/bin/passwd")
15854 A default set of setuid programs is defined by the
15855 @code{%setuid-programs} variable of the @code{(gnu system)} module.
15857 @defvr {Scheme Variable} %setuid-programs
15858 A list of G-expressions denoting common programs that are setuid-root.
15860 The list includes commands such as @command{passwd}, @command{ping},
15861 @command{su}, and @command{sudo}.
15864 Under the hood, the actual setuid programs are created in the
15865 @file{/run/setuid-programs} directory at system activation time. The
15866 files in this directory refer to the ``real'' binaries, which are in the
15869 @node X.509 Certificates
15870 @subsection X.509 Certificates
15872 @cindex HTTPS, certificates
15873 @cindex X.509 certificates
15875 Web servers available over HTTPS (that is, HTTP over the transport-layer
15876 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
15877 that the client can then use to @emph{authenticate} the server. To do
15878 that, clients verify that the server's certificate is signed by a
15879 so-called @dfn{certificate authority} (CA). But to verify the CA's
15880 signature, clients must have first acquired the CA's certificate.
15882 Web browsers such as GNU@tie{}IceCat include their own set of CA
15883 certificates, such that they are able to verify CA signatures
15886 However, most other programs that can talk HTTPS---@command{wget},
15887 @command{git}, @command{w3m}, etc.---need to be told where CA
15888 certificates can be found.
15890 @cindex @code{nss-certs}
15891 In GuixSD, this is done by adding a package that provides certificates
15892 to the @code{packages} field of the @code{operating-system} declaration
15893 (@pxref{operating-system Reference}). GuixSD includes one such package,
15894 @code{nss-certs}, which is a set of CA certificates provided as part of
15895 Mozilla's Network Security Services.
15897 Note that it is @emph{not} part of @var{%base-packages}, so you need to
15898 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
15899 most applications and libraries look for certificates by default, points
15900 to the certificates installed globally.
15902 Unprivileged users, including users of Guix on a foreign distro,
15903 can also install their own certificate package in
15904 their profile. A number of environment variables need to be defined so
15905 that applications and libraries know where to find them. Namely, the
15906 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
15907 variables. Some applications add their own environment variables; for
15908 instance, the Git version control system honors the certificate bundle
15909 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
15910 would typically run something like:
15913 $ guix package -i nss-certs
15914 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
15915 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
15916 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
15919 As another example, R requires the @code{CURL_CA_BUNDLE} environment
15920 variable to point to a certificate bundle, so you would have to run
15921 something like this:
15924 $ guix package -i nss-certs
15925 $ export CURL_CA_BUNDLE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
15928 For other applications you may want to look up the required environment
15929 variable in the relevant documentation.
15932 @node Name Service Switch
15933 @subsection Name Service Switch
15935 @cindex name service switch
15937 The @code{(gnu system nss)} module provides bindings to the
15938 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
15939 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
15940 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
15941 extended with new ``name'' lookup methods for system databases, which
15942 includes host names, service names, user accounts, and more (@pxref{Name
15943 Service Switch, System Databases and Name Service Switch,, libc, The GNU
15944 C Library Reference Manual}).
15946 The NSS configuration specifies, for each system database, which lookup
15947 method is to be used, and how the various methods are chained
15948 together---for instance, under which circumstances NSS should try the
15949 next method in the list. The NSS configuration is given in the
15950 @code{name-service-switch} field of @code{operating-system} declarations
15951 (@pxref{operating-system Reference, @code{name-service-switch}}).
15954 @cindex .local, host name lookup
15955 As an example, the declaration below configures the NSS to use the
15956 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
15957 back-end}, which supports host name lookups over multicast DNS (mDNS)
15958 for host names ending in @code{.local}:
15961 (name-service-switch
15962 (hosts (list %files ;first, check /etc/hosts
15964 ;; If the above did not succeed, try
15965 ;; with 'mdns_minimal'.
15967 (name "mdns_minimal")
15969 ;; 'mdns_minimal' is authoritative for
15970 ;; '.local'. When it returns "not found",
15971 ;; no need to try the next methods.
15972 (reaction (lookup-specification
15973 (not-found => return))))
15975 ;; Then fall back to DNS.
15979 ;; Finally, try with the "full" 'mdns'.
15984 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
15985 contains this configuration, so you will not have to type it if all you
15986 want is to have @code{.local} host lookup working.
15988 Note that, in this case, in addition to setting the
15989 @code{name-service-switch} of the @code{operating-system} declaration,
15990 you also need to use @code{avahi-service} (@pxref{Networking Services,
15991 @code{avahi-service}}), or @var{%desktop-services}, which includes it
15992 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
15993 to the name service cache daemon (@pxref{Base Services,
15994 @code{nscd-service}}).
15996 For convenience, the following variables provide typical NSS
15999 @defvr {Scheme Variable} %default-nss
16000 This is the default name service switch configuration, a
16001 @code{name-service-switch} object.
16004 @defvr {Scheme Variable} %mdns-host-lookup-nss
16005 This is the name service switch configuration with support for host name
16006 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
16009 The reference for name service switch configuration is given below. It
16010 is a direct mapping of the configuration file format of the C library , so
16011 please refer to the C library manual for more information (@pxref{NSS
16012 Configuration File,,, libc, The GNU C Library Reference Manual}).
16013 Compared to the configuration file format of libc NSS, it has the advantage
16014 not only of adding this warm parenthetic feel that we like, but also
16015 static checks: you will know about syntax errors and typos as soon as you
16016 run @command{guix system}.
16018 @deftp {Data Type} name-service-switch
16020 This is the data type representation the configuration of libc's name
16021 service switch (NSS). Each field below represents one of the supported
16038 The system databases handled by the NSS. Each of these fields must be a
16039 list of @code{<name-service>} objects (see below).
16043 @deftp {Data Type} name-service
16045 This is the data type representing an actual name service and the
16046 associated lookup action.
16050 A string denoting the name service (@pxref{Services in the NSS
16051 configuration,,, libc, The GNU C Library Reference Manual}).
16053 Note that name services listed here must be visible to nscd. This is
16054 achieved by passing the @code{#:name-services} argument to
16055 @code{nscd-service} the list of packages providing the needed name
16056 services (@pxref{Base Services, @code{nscd-service}}).
16059 An action specified using the @code{lookup-specification} macro
16060 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
16061 Reference Manual}). For example:
16064 (lookup-specification (unavailable => continue)
16065 (success => return))
16070 @node Initial RAM Disk
16071 @subsection Initial RAM Disk
16074 @cindex initial RAM disk
16075 For bootstrapping purposes, the Linux-Libre kernel is passed an
16076 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
16077 root file system as well as an initialization script. The latter is
16078 responsible for mounting the real root file system, and for loading any
16079 kernel modules that may be needed to achieve that.
16081 The @code{initrd} field of an @code{operating-system} declaration allows
16082 you to specify which initrd you would like to use. The @code{(gnu
16083 system linux-initrd)} module provides three ways to build an initrd: the
16084 high-level @code{base-initrd} procedure and the low-level
16085 @code{raw-initrd} and @code{expression->initrd} procedures.
16087 The @code{base-initrd} procedure is intended to cover most common uses.
16088 For example, if you want to add a bunch of kernel modules to be loaded
16089 at boot time, you can define the @code{initrd} field of the operating
16090 system declaration like this:
16093 (initrd (lambda (file-systems . rest)
16094 ;; Create a standard initrd that has modules "foo.ko"
16095 ;; and "bar.ko", as well as their dependencies, in
16096 ;; addition to the modules available by default.
16097 (apply base-initrd file-systems
16098 #:extra-modules '("foo" "bar")
16102 The @code{base-initrd} procedure also handles common use cases that
16103 involves using the system as a QEMU guest, or as a ``live'' system with
16104 volatile root file system.
16106 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
16107 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
16108 such as trying to guess which kernel modules and packages should be included
16109 to the initrd. An example use of @code{raw-initrd} is when a user has
16110 a custom Linux kernel configuration and default kernel modules included by
16111 @code{base-initrd} are not available.
16113 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
16114 honors several options passed on the Linux kernel command line
16115 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
16116 @code{-append} option of QEMU), notably:
16119 @item --load=@var{boot}
16120 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
16121 program, once it has mounted the root file system.
16123 GuixSD uses this option to yield control to a boot program that runs the
16124 service activation programs and then spawns the GNU@tie{}Shepherd, the
16125 initialization system.
16127 @item --root=@var{root}
16128 Mount @var{root} as the root file system. @var{root} can be a
16129 device name like @code{/dev/sda1}, a partition label, or a partition
16132 @item --system=@var{system}
16133 Have @file{/run/booted-system} and @file{/run/current-system} point to
16136 @item modprobe.blacklist=@var{modules}@dots{}
16137 @cindex module, black-listing
16138 @cindex black list, of kernel modules
16139 Instruct the initial RAM disk as well as the @command{modprobe} command
16140 (from the kmod package) to refuse to load @var{modules}. @var{modules}
16141 must be a comma-separated list of module names---e.g.,
16142 @code{usbkbd,9pnet}.
16145 Start a read-eval-print loop (REPL) from the initial RAM disk before it
16146 tries to load kernel modules and to mount the root file system. Our
16147 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
16148 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
16149 Manual}, for more information on Guile's REPL.
16153 Now that you know all the features that initial RAM disks produced by
16154 @code{base-initrd} and @code{raw-initrd} provide,
16155 here is how to use it and customize it further.
16158 @cindex initial RAM disk
16159 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
16160 [#:linux-modules '()] [#:mapped-devices '()] @
16161 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
16162 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
16163 a list of file systems to be mounted by the initrd, possibly in addition to
16164 the root file system specified on the kernel command line via @code{--root}.
16165 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
16166 @var{mapped-devices} is a list of device mappings to realize before
16167 @var{file-systems} are mounted (@pxref{Mapped Devices}).
16168 @var{helper-packages} is a list of packages to be copied in the initrd. It may
16169 include @code{e2fsck/static} or other packages needed by the initrd to check
16172 When @var{qemu-networking?} is true, set up networking with the standard QEMU
16173 parameters. When @var{virtio?} is true, load additional modules so that the
16174 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
16176 When @var{volatile-root?} is true, the root file system is writable but any changes
16180 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
16181 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
16182 [#:virtio? #t] [#:extra-modules '()]
16183 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
16184 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
16185 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
16186 also behaves as in @code{raw-initrd}.
16188 When @var{virtio?} is true, load additional modules so that the
16189 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
16191 The initrd is automatically populated with all the kernel modules necessary
16192 for @var{file-systems} and for the given options. However, additional kernel
16193 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
16194 loaded at boot time in the order in which they appear.
16197 Needless to say, the initrds we produce and use embed a
16198 statically-linked Guile, and the initialization program is a Guile
16199 program. That gives a lot of flexibility. The
16200 @code{expression->initrd} procedure builds such an initrd, given the
16201 program to run in that initrd.
16203 @deffn {Monadic Procedure} expression->initrd @var{exp} @
16204 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
16205 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
16206 containing @var{guile} and that evaluates @var{exp}, a G-expression,
16207 upon booting. All the derivations referenced by @var{exp} are
16208 automatically copied to the initrd.
16211 @node Bootloader Configuration
16212 @subsection Bootloader Configuration
16215 @cindex boot loader
16217 The operating system supports multiple bootloaders. The bootloader is
16218 configured using @code{bootloader-configuration} declaration. All the
16219 fields of this structure are bootloader agnostic except for one field,
16220 @code{bootloader} that indicates the bootloader to be configured and
16223 Some of the bootloaders do not honor every field of
16224 @code{bootloader-configuration}. For instance, the extlinux
16225 bootloader does not support themes and thus ignores the @code{theme}
16228 @deftp {Data Type} bootloader-configuration
16229 The type of a bootloader configuration declaration.
16233 @item @code{bootloader}
16234 @cindex EFI, bootloader
16235 @cindex UEFI, bootloader
16236 @cindex BIOS, bootloader
16237 The bootloader to use, as a @code{bootloader} object. For now
16238 @code{grub-bootloader}, @code{grub-efi-bootloader},
16239 @code{extlinux-bootloader} and @code{u-boot-bootloader} are supported.
16240 @code{grub-efi-bootloader} allows to boot on modern systems using the
16241 @dfn{Unified Extensible Firmware Interface} (UEFI).
16243 Available bootloaders are described in @code{(gnu bootloader @dots{})}
16246 @item @code{device}
16247 This is a string denoting the boot device. It must be a device name
16248 understood by the bootloader @command{installer} command, such as
16249 @code{/dev/sda} or @code{(hd0)} (for GRUB, @pxref{Invoking grub-install,,, grub,
16252 @item @code{menu-entries} (default: @code{()})
16253 A possibly empty list of @code{menu-entry} objects (see below), denoting
16254 entries to appear in the bootloader menu, in addition to the current
16255 system entry and the entry pointing to previous system generations.
16258 @item @code{default-entry} (default: @code{0})
16259 The index of the default boot menu entry. Index 0 is for the entry of the
16262 @item @code{timeout} (default: @code{5})
16263 The number of seconds to wait for keyboard input before booting. Set to
16264 0 to boot immediately, and to -1 to wait indefinitely.
16266 @item @code{theme} (default: @var{#f})
16267 The bootloader theme object describing the theme to use. If no theme
16268 is provided, some bootloaders might use a default theme, that's true
16271 @item @code{terminal-outputs} (default: @code{'gfxterm})
16272 The output terminals used for the bootloader boot menu, as a list of
16273 symbols. GRUB accepts the values: @code{console}, @code{serial},
16274 @code{serial_@{0-3@}}, @code{gfxterm}, @code{vga_text},
16275 @code{mda_text}, @code{morse}, and @code{pkmodem}. This field
16276 corresponds to the GRUB variable GRUB_TERMINAL_OUTPUT (@pxref{Simple
16277 configuration,,, grub,GNU GRUB manual}).
16279 @item @code{terminal-inputs} (default: @code{'()})
16280 The input terminals used for the bootloader boot menu, as a list of
16281 symbols. For GRUB, the default is the native platform terminal as
16282 determined at run-time. GRUB accepts the values: @code{console},
16283 @code{serial}, @code{serial_@{0-3@}}, @code{at_keyboard}, and
16284 @code{usb_keyboard}. This field corresponds to the GRUB variable
16285 GRUB_TERMINAL_INPUT (@pxref{Simple configuration,,, grub,GNU GRUB
16288 @item @code{serial-unit} (default: @code{#f})
16289 The serial unit used by the bootloader, as an integer from 0 to 3.
16290 For GRUB it is choosen at run-time; currently GRUB chooses 0, which
16291 corresponds to COM1 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
16293 @item @code{serial-speed} (default: @code{#f})
16294 The speed of the serial interface, as an integer. For GRUB, the
16295 default value is chosen at run-time; currently GRUB chooses
16296 9600@tie{}bps (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
16303 Should you want to list additional boot menu entries @i{via} the
16304 @code{menu-entries} field above, you will need to create them with the
16305 @code{menu-entry} form. For example, imagine you want to be able to
16306 boot another distro (hard to imagine!), you can define a menu entry
16311 (label "The Other Distro")
16312 (linux "/boot/old/vmlinux-2.6.32")
16313 (linux-arguments '("root=/dev/sda2"))
16314 (initrd "/boot/old/initrd"))
16319 @deftp {Data Type} menu-entry
16320 The type of an entry in the bootloader menu.
16325 The label to show in the menu---e.g., @code{"GNU"}.
16328 The Linux kernel image to boot, for example:
16331 (file-append linux-libre "/bzImage")
16334 For GRUB, it is also possible to specify a device explicitly in the
16335 file path using GRUB's device naming convention (@pxref{Naming
16336 convention,,, grub, GNU GRUB manual}), for example:
16339 "(hd0,msdos1)/boot/vmlinuz"
16342 If the device is specified explicitly as above, then the @code{device}
16343 field is ignored entirely.
16345 @item @code{linux-arguments} (default: @code{()})
16346 The list of extra Linux kernel command-line arguments---e.g.,
16347 @code{("console=ttyS0")}.
16349 @item @code{initrd}
16350 A G-Expression or string denoting the file name of the initial RAM disk
16351 to use (@pxref{G-Expressions}).
16352 @item @code{device} (default: @code{#f})
16353 The device where the kernel and initrd are to be found---i.e., for GRUB,
16354 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
16356 This may be a file system label (a string), a file system UUID (a
16357 bytevector, @pxref{File Systems}), or @code{#f}, in which case
16358 the bootloader will search the device containing the file specified by
16359 the @code{linux} field (@pxref{search,,, grub, GNU GRUB manual}). It
16360 must @emph{not} be an OS device name such as @file{/dev/sda1}.
16365 @c FIXME: Write documentation once it's stable.
16366 Fow now only GRUB has theme support. GRUB themes are created using
16367 the @code{grub-theme} form, which is not documented yet.
16369 @defvr {Scheme Variable} %default-theme
16370 This is the default GRUB theme used by the operating system if no
16371 @code{theme} field is specified in @code{bootloader-configuration}
16374 It comes with a fancy background image displaying the GNU and Guix
16379 @node Invoking guix system
16380 @subsection Invoking @code{guix system}
16382 Once you have written an operating system declaration as seen in the
16383 previous section, it can be @dfn{instantiated} using the @command{guix
16384 system} command. The synopsis is:
16387 guix system @var{options}@dots{} @var{action} @var{file}
16390 @var{file} must be the name of a file containing an
16391 @code{operating-system} declaration. @var{action} specifies how the
16392 operating system is instantiated. Currently the following values are
16397 Build the operating system described in @var{file}, activate it, and
16398 switch to it@footnote{This action (and the related actions
16399 @code{switch-generation} and @code{roll-back}) are usable only on
16400 systems already running GuixSD.}.
16402 This effects all the configuration specified in @var{file}: user
16403 accounts, system services, global package list, setuid programs, etc.
16404 The command starts system services specified in @var{file} that are not
16405 currently running; if a service is currently running, it does not
16406 attempt to upgrade it since this would not be possible without stopping it
16409 This command creates a new generation whose number is one greater than
16410 the current generation (as reported by @command{guix system
16411 list-generations}). If that generation already exists, it will be
16412 overwritten. This behavior mirrors that of @command{guix package}
16413 (@pxref{Invoking guix package}).
16415 It also adds a bootloader menu entry for the new OS configuration,
16416 ---unless @option{--no-bootloader} is passed. For GRUB, it moves
16417 entries for older configurations to a submenu, allowing you to choose
16418 an older system generation at boot time should you need it.
16421 @c The paragraph below refers to the problem discussed at
16422 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
16423 It is highly recommended to run @command{guix pull} once before you run
16424 @command{guix system reconfigure} for the first time (@pxref{Invoking
16425 guix pull}). Failing to do that you would see an older version of Guix
16426 once @command{reconfigure} has completed.
16429 @item switch-generation
16430 @cindex generations
16431 Switch to an existing system generation. This action atomically
16432 switches the system profile to the specified system generation. It
16433 also rearranges the system's existing bootloader menu entries. It
16434 makes the menu entry for the specified system generation the default,
16435 and it moves the entries for the other generatiors to a submenu, if
16436 supported by the bootloader being used. The next time the system
16437 boots, it will use the specified system generation.
16439 The bootloader itself is not being reinstalled when using this
16440 command. Thus, the installed bootloader is used with an updated
16441 configuration file.
16443 The target generation can be specified explicitly by its generation
16444 number. For example, the following invocation would switch to system
16448 guix system switch-generation 7
16451 The target generation can also be specified relative to the current
16452 generation with the form @code{+N} or @code{-N}, where @code{+3} means
16453 ``3 generations ahead of the current generation,'' and @code{-1} means
16454 ``1 generation prior to the current generation.'' When specifying a
16455 negative value such as @code{-1}, you must precede it with @code{--} to
16456 prevent it from being parsed as an option. For example:
16459 guix system switch-generation -- -1
16462 Currently, the effect of invoking this action is @emph{only} to switch
16463 the system profile to an existing generation and rearrange the
16464 bootloader menu entries. To actually start using the target system
16465 generation, you must reboot after running this action. In the future,
16466 it will be updated to do the same things as @command{reconfigure},
16467 like activating and deactivating services.
16469 This action will fail if the specified generation does not exist.
16472 @cindex rolling back
16473 Switch to the preceding system generation. The next time the system
16474 boots, it will use the preceding system generation. This is the inverse
16475 of @command{reconfigure}, and it is exactly the same as invoking
16476 @command{switch-generation} with an argument of @code{-1}.
16478 Currently, as with @command{switch-generation}, you must reboot after
16479 running this action to actually start using the preceding system
16483 Build the derivation of the operating system, which includes all the
16484 configuration files and programs needed to boot and run the system.
16485 This action does not actually install anything.
16488 Populate the given directory with all the files necessary to run the
16489 operating system specified in @var{file}. This is useful for first-time
16490 installations of GuixSD. For instance:
16493 guix system init my-os-config.scm /mnt
16496 copies to @file{/mnt} all the store items required by the configuration
16497 specified in @file{my-os-config.scm}. This includes configuration
16498 files, packages, and so on. It also creates other essential files
16499 needed for the system to operate correctly---e.g., the @file{/etc},
16500 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
16502 This command also installs bootloader on the device specified in
16503 @file{my-os-config}, unless the @option{--no-bootloader} option was
16507 @cindex virtual machine
16509 @anchor{guix system vm}
16510 Build a virtual machine that contains the operating system declared in
16511 @var{file}, and return a script to run that virtual machine (VM).
16512 Arguments given to the script are passed to QEMU as in the example
16513 below, which enables networking and requests 1@tie{}GiB of RAM for the
16517 $ /gnu/store/@dots{}-run-vm.sh -m 1024 -net user
16520 The VM shares its store with the host system.
16522 Additional file systems can be shared between the host and the VM using
16523 the @code{--share} and @code{--expose} command-line options: the former
16524 specifies a directory to be shared with write access, while the latter
16525 provides read-only access to the shared directory.
16527 The example below creates a VM in which the user's home directory is
16528 accessible read-only, and where the @file{/exchange} directory is a
16529 read-write mapping of @file{$HOME/tmp} on the host:
16532 guix system vm my-config.scm \
16533 --expose=$HOME --share=$HOME/tmp=/exchange
16536 On GNU/Linux, the default is to boot directly to the kernel; this has
16537 the advantage of requiring only a very tiny root disk image since the
16538 store of the host can then be mounted.
16540 The @code{--full-boot} option forces a complete boot sequence, starting
16541 with the bootloader. This requires more disk space since a root image
16542 containing at least the kernel, initrd, and bootloader data files must
16543 be created. The @code{--image-size} option can be used to specify the
16548 Return a virtual machine or disk image of the operating system declared
16549 in @var{file} that stands alone. By default, @command{guix system}
16550 estimates the size of the image needed to store the system, but you can
16551 use the @option{--image-size} option to specify a value.
16553 You can specify the root file system type by using the
16554 @option{--file-system-type} option. It defaults to @code{ext4}.
16556 When using @code{vm-image}, the returned image is in qcow2 format, which
16557 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
16558 for more information on how to run the image in a virtual machine.
16560 When using @code{disk-image}, a raw disk image is produced; it can be
16561 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
16562 the device corresponding to a USB stick, one can copy the image to it
16563 using the following command:
16566 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
16570 Return a script to run the operating system declared in @var{file}
16571 within a container. Containers are a set of lightweight isolation
16572 mechanisms provided by the kernel Linux-libre. Containers are
16573 substantially less resource-demanding than full virtual machines since
16574 the kernel, shared objects, and other resources can be shared with the
16575 host system; this also means they provide thinner isolation.
16577 Currently, the script must be run as root in order to support more than
16578 a single user and group. The container shares its store with the host
16581 As with the @code{vm} action (@pxref{guix system vm}), additional file
16582 systems to be shared between the host and container can be specified
16583 using the @option{--share} and @option{--expose} options:
16586 guix system container my-config.scm \
16587 --expose=$HOME --share=$HOME/tmp=/exchange
16591 This option requires Linux-libre 3.19 or newer.
16596 @var{options} can contain any of the common build options (@pxref{Common
16597 Build Options}). In addition, @var{options} can contain one of the
16601 @item --system=@var{system}
16602 @itemx -s @var{system}
16603 Attempt to build for @var{system} instead of the host system type.
16604 This works as per @command{guix build} (@pxref{Invoking guix build}).
16608 Return the derivation file name of the given operating system without
16611 @item --file-system-type=@var{type}
16612 @itemx -t @var{type}
16613 For the @code{disk-image} action, create a file system of the given
16614 @var{type} on the image.
16616 When this option is omitted, @command{guix system} uses @code{ext4}.
16618 @cindex ISO-9660 format
16619 @cindex CD image format
16620 @cindex DVD image format
16621 @code{--file-system-type=iso9660} produces an ISO-9660 image, suitable
16622 for burning on CDs and DVDs.
16624 @item --image-size=@var{size}
16625 For the @code{vm-image} and @code{disk-image} actions, create an image
16626 of the given @var{size}. @var{size} may be a number of bytes, or it may
16627 include a unit as a suffix (@pxref{Block size, size specifications,,
16628 coreutils, GNU Coreutils}).
16630 When this option is omitted, @command{guix system} computes an estimate
16631 of the image size as a function of the size of the system declared in
16634 @item --root=@var{file}
16635 @itemx -r @var{file}
16636 Make @var{file} a symlink to the result, and register it as a garbage
16639 @item --on-error=@var{strategy}
16640 Apply @var{strategy} when an error occurs when reading @var{file}.
16641 @var{strategy} may be one of the following:
16644 @item nothing-special
16645 Report the error concisely and exit. This is the default strategy.
16648 Likewise, but also display a backtrace.
16651 Report the error and enter Guile's debugger. From there, you can run
16652 commands such as @code{,bt} to get a backtrace, @code{,locals} to
16653 display local variable values, and more generally inspect the state of the
16654 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
16655 a list of available debugging commands.
16660 All the actions above, except @code{build} and @code{init},
16661 can use KVM support in the Linux-libre kernel. Specifically, if the
16662 machine has hardware virtualization support, the corresponding
16663 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
16664 must exist and be readable and writable by the user and by the
16665 build users of the daemon (@pxref{Build Environment Setup}).
16668 Once you have built, configured, re-configured, and re-re-configured
16669 your GuixSD installation, you may find it useful to list the operating
16670 system generations available on disk---and that you can choose from the
16671 bootloader boot menu:
16675 @item list-generations
16676 List a summary of each generation of the operating system available on
16677 disk, in a human-readable way. This is similar to the
16678 @option{--list-generations} option of @command{guix package}
16679 (@pxref{Invoking guix package}).
16681 Optionally, one can specify a pattern, with the same syntax that is used
16682 in @command{guix package --list-generations}, to restrict the list of
16683 generations displayed. For instance, the following command displays
16684 generations that are up to 10 days old:
16687 $ guix system list-generations 10d
16692 The @command{guix system} command has even more to offer! The following
16693 sub-commands allow you to visualize how your system services relate to
16696 @anchor{system-extension-graph}
16699 @item extension-graph
16700 Emit in Dot/Graphviz format to standard output the @dfn{service
16701 extension graph} of the operating system defined in @var{file}
16702 (@pxref{Service Composition}, for more information on service
16708 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
16711 produces a PDF file showing the extension relations among services.
16713 @anchor{system-shepherd-graph}
16714 @item shepherd-graph
16715 Emit in Dot/Graphviz format to standard output the @dfn{dependency
16716 graph} of shepherd services of the operating system defined in
16717 @var{file}. @xref{Shepherd Services}, for more information and for an
16722 @node Running GuixSD in a VM
16723 @subsection Running GuixSD in a Virtual Machine
16725 @cindex virtual machine
16726 To run GuixSD in a virtual machine (VM), one can either use the
16727 pre-built GuixSD VM image distributed at
16728 @indicateurl{ftp://alpha.gnu.org/guix/guixsd-vm-image-@value{VERSION}.@var{system}.tar.xz}
16729 , or build their own virtual machine image using @command{guix system
16730 vm-image} (@pxref{Invoking guix system}). The returned image is in
16731 qcow2 format, which the @uref{http://qemu.org/, QEMU emulator} can
16735 If you built your own image, you must copy it out of the store
16736 (@pxref{The Store}) and give yourself permission to write to the copy
16737 before you can use it. When invoking QEMU, you must choose a system
16738 emulator that is suitable for your hardware platform. Here is a minimal
16739 QEMU invocation that will boot the result of @command{guix system
16740 vm-image} on x86_64 hardware:
16743 $ qemu-system-x86_64 \
16744 -net user -net nic,model=virtio \
16745 -enable-kvm -m 256 /tmp/qemu-image
16748 Here is what each of these options means:
16751 @item qemu-system-x86_64
16752 This specifies the hardware platform to emulate. This should match the
16756 Enable the unprivileged user-mode network stack. The guest OS can
16757 access the host but not vice versa. This is the simplest way to get the
16760 @item -net nic,model=virtio
16761 You must create a network interface of a given model. If you do not
16762 create a NIC, the boot will fail. Assuming your hardware platform is
16763 x86_64, you can get a list of available NIC models by running
16764 @command{qemu-system-x86_64 -net nic,model=help}.
16767 If your system has hardware virtualization extensions, enabling the
16768 virtual machine support (KVM) of the Linux kernel will make things run
16772 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
16773 which may be insufficient for some operations.
16775 @item /tmp/qemu-image
16776 The file name of the qcow2 image.
16779 The default @command{run-vm.sh} script that is returned by an invocation of
16780 @command{guix system vm} does not add a @command{-net user} flag by default.
16781 To get network access from within the vm add the @code{(dhcp-client-service)}
16782 to your system definition and start the VM using
16783 @command{`guix system vm config.scm` -net user}. An important caveat of using
16784 @command{-net user} for networking is that @command{ping} will not work, because
16785 it uses the ICMP protocol. You'll have to use a different command to check for
16786 network connectivity, for example @command{guix download}.
16788 @subsubsection Connecting Through SSH
16792 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
16793 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
16794 boot unsupervised. It requires you to type some characters to initialize the
16795 randomness generator. In addition you need to forward the SSH port, 22 by
16796 default, to the host. You can do this with
16799 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
16802 To connect to the VM you can run
16805 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
16808 The @command{-p} tells @command{ssh} the port you want to connect to.
16809 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
16810 every time you modify your @command{config.scm} file and the
16811 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
16812 connection to an unknown host every time you connect.
16814 @subsubsection Using @command{virt-viewer} with Spice
16816 As an alternative to the default @command{qemu} graphical client you can
16817 use the @command{remote-viewer} from the @command{virt-viewer} package. To
16818 connect pass the @command{-spice port=5930,disable-ticketing} flag to
16819 @command{qemu}. See previous section for further information on how to do this.
16821 Spice also allows you to do some nice stuff like share your clipboard with your
16822 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
16825 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
16826 -chardev spicevmc,name=vdagent,id=vdagent
16827 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
16828 name=com.redhat.spice.0
16831 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
16833 @node Defining Services
16834 @subsection Defining Services
16836 The previous sections show the available services and how one can combine
16837 them in an @code{operating-system} declaration. But how do we define
16838 them in the first place? And what is a service anyway?
16841 * Service Composition:: The model for composing services.
16842 * Service Types and Services:: Types and services.
16843 * Service Reference:: API reference.
16844 * Shepherd Services:: A particular type of service.
16847 @node Service Composition
16848 @subsubsection Service Composition
16852 Here we define a @dfn{service} as, broadly, something that extends the
16853 functionality of the operating system. Often a service is a process---a
16854 @dfn{daemon}---started when the system boots: a secure shell server, a
16855 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
16856 whose execution can be triggered by another daemon---e.g., an FTP server
16857 started by @command{inetd} or a D-Bus service activated by
16858 @command{dbus-daemon}. Occasionally, a service does not map to a
16859 daemon. For instance, the ``account'' service collects user accounts
16860 and makes sure they exist when the system runs; the ``udev'' service
16861 collects device management rules and makes them available to the eudev
16862 daemon; the @file{/etc} service populates the @file{/etc} directory
16865 @cindex service extensions
16866 GuixSD services are connected by @dfn{extensions}. For instance, the
16867 secure shell service @emph{extends} the Shepherd---the GuixSD
16868 initialization system, running as PID@tie{}1---by giving it the command
16869 lines to start and stop the secure shell daemon (@pxref{Networking
16870 Services, @code{lsh-service}}); the UPower service extends the D-Bus
16871 service by passing it its @file{.service} specification, and extends the
16872 udev service by passing it device management rules (@pxref{Desktop
16873 Services, @code{upower-service}}); the Guix daemon service extends the
16874 Shepherd by passing it the command lines to start and stop the daemon,
16875 and extends the account service by passing it a list of required build
16876 user accounts (@pxref{Base Services}).
16878 All in all, services and their ``extends'' relations form a directed
16879 acyclic graph (DAG). If we represent services as boxes and extensions
16880 as arrows, a typical system might provide something like this:
16882 @image{images/service-graph,,5in,Typical service extension graph.}
16884 @cindex system service
16885 At the bottom, we see the @dfn{system service}, which produces the
16886 directory containing everything to run and boot the system, as returned
16887 by the @command{guix system build} command. @xref{Service Reference},
16888 to learn about the other service types shown here.
16889 @xref{system-extension-graph, the @command{guix system extension-graph}
16890 command}, for information on how to generate this representation for a
16891 particular operating system definition.
16893 @cindex service types
16894 Technically, developers can define @dfn{service types} to express these
16895 relations. There can be any number of services of a given type on the
16896 system---for instance, a system running two instances of the GNU secure
16897 shell server (lsh) has two instances of @var{lsh-service-type}, with
16898 different parameters.
16900 The following section describes the programming interface for service
16901 types and services.
16903 @node Service Types and Services
16904 @subsubsection Service Types and Services
16906 A @dfn{service type} is a node in the DAG described above. Let us start
16907 with a simple example, the service type for the Guix build daemon
16908 (@pxref{Invoking guix-daemon}):
16911 (define guix-service-type
16915 (list (service-extension shepherd-root-service-type guix-shepherd-service)
16916 (service-extension account-service-type guix-accounts)
16917 (service-extension activation-service-type guix-activation)))
16918 (default-value (guix-configuration))))
16922 It defines three things:
16926 A name, whose sole purpose is to make inspection and debugging easier.
16929 A list of @dfn{service extensions}, where each extension designates the
16930 target service type and a procedure that, given the parameters of the
16931 service, returns a list of objects to extend the service of that type.
16933 Every service type has at least one service extension. The only
16934 exception is the @dfn{boot service type}, which is the ultimate service.
16937 Optionally, a default value for instances of this type.
16940 In this example, @var{guix-service-type} extends three services:
16943 @item shepherd-root-service-type
16944 The @var{guix-shepherd-service} procedure defines how the Shepherd
16945 service is extended. Namely, it returns a @code{<shepherd-service>}
16946 object that defines how @command{guix-daemon} is started and stopped
16947 (@pxref{Shepherd Services}).
16949 @item account-service-type
16950 This extension for this service is computed by @var{guix-accounts},
16951 which returns a list of @code{user-group} and @code{user-account}
16952 objects representing the build user accounts (@pxref{Invoking
16955 @item activation-service-type
16956 Here @var{guix-activation} is a procedure that returns a gexp, which is
16957 a code snippet to run at ``activation time''---e.g., when the service is
16961 A service of this type is instantiated like this:
16964 (service guix-service-type
16965 (guix-configuration
16967 (use-substitutes? #f)))
16970 The second argument to the @code{service} form is a value representing
16971 the parameters of this specific service instance.
16972 @xref{guix-configuration-type, @code{guix-configuration}}, for
16973 information about the @code{guix-configuration} data type. When the
16974 value is omitted, the default value specified by
16975 @code{guix-service-type} is used:
16978 (service guix-service-type)
16981 @var{guix-service-type} is quite simple because it extends other
16982 services but is not extensible itself.
16984 @c @subsubsubsection Extensible Service Types
16986 The service type for an @emph{extensible} service looks like this:
16989 (define udev-service-type
16990 (service-type (name 'udev)
16992 (list (service-extension shepherd-root-service-type
16993 udev-shepherd-service)))
16995 (compose concatenate) ;concatenate the list of rules
16996 (extend (lambda (config rules)
16998 (($ <udev-configuration> udev initial-rules)
16999 (udev-configuration
17000 (udev udev) ;the udev package to use
17001 (rules (append initial-rules rules)))))))))
17004 This is the service type for the
17005 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
17006 management daemon}. Compared to the previous example, in addition to an
17007 extension of @var{shepherd-root-service-type}, we see two new fields:
17011 This is the procedure to @dfn{compose} the list of extensions to
17012 services of this type.
17014 Services can extend the udev service by passing it lists of rules; we
17015 compose those extensions simply by concatenating them.
17018 This procedure defines how the value of the service is @dfn{extended} with
17019 the composition of the extensions.
17021 Udev extensions are composed into a list of rules, but the udev service
17022 value is itself a @code{<udev-configuration>} record. So here, we
17023 extend that record by appending the list of rules it contains to the
17024 list of contributed rules.
17027 There can be only one instance of an extensible service type such as
17028 @var{udev-service-type}. If there were more, the
17029 @code{service-extension} specifications would be ambiguous.
17031 Still here? The next section provides a reference of the programming
17032 interface for services.
17034 @node Service Reference
17035 @subsubsection Service Reference
17037 We have seen an overview of service types (@pxref{Service Types and
17038 Services}). This section provides a reference on how to manipulate
17039 services and service types. This interface is provided by the
17040 @code{(gnu services)} module.
17042 @deffn {Scheme Procedure} service @var{type} [@var{value}]
17043 Return a new service of @var{type}, a @code{<service-type>} object (see
17044 below.) @var{value} can be any object; it represents the parameters of
17045 this particular service instance.
17047 When @var{value} is omitted, the default value specified by @var{type}
17048 is used; if @var{type} does not specify a default value, an error is
17051 For instance, this:
17054 (service openssh-service-type)
17058 is equivalent to this:
17061 (service openssh-service-type
17062 (openssh-configuration))
17065 In both cases the result is an instance of @code{openssh-service-type}
17066 with the default configuration.
17069 @deffn {Scheme Procedure} service? @var{obj}
17070 Return true if @var{obj} is a service.
17073 @deffn {Scheme Procedure} service-kind @var{service}
17074 Return the type of @var{service}---i.e., a @code{<service-type>} object.
17077 @deffn {Scheme Procedure} service-value @var{service}
17078 Return the value associated with @var{service}. It represents its
17082 Here is an example of how a service is created and manipulated:
17086 (service nginx-service-type
17087 (nginx-configuration
17089 (log-directory log-directory)
17090 (run-directory run-directory)
17091 (file config-file))))
17096 (eq? (service-kind s) nginx-service-type)
17100 The @code{modify-services} form provides a handy way to change the
17101 parameters of some of the services of a list such as
17102 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
17103 evaluates to a list of services. Of course, you could always use
17104 standard list combinators such as @code{map} and @code{fold} to do that
17105 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
17106 @code{modify-services} simply provides a more concise form for this
17109 @deffn {Scheme Syntax} modify-services @var{services} @
17110 (@var{type} @var{variable} => @var{body}) @dots{}
17112 Modify the services listed in @var{services} according to the given
17113 clauses. Each clause has the form:
17116 (@var{type} @var{variable} => @var{body})
17119 where @var{type} is a service type---e.g.,
17120 @code{guix-service-type}---and @var{variable} is an identifier that is
17121 bound within the @var{body} to the service parameters---e.g., a
17122 @code{guix-configuration} instance---of the original service of that
17125 The @var{body} should evaluate to the new service parameters, which will
17126 be used to configure the new service. This new service will replace the
17127 original in the resulting list. Because a service's service parameters
17128 are created using @code{define-record-type*}, you can write a succinct
17129 @var{body} that evaluates to the new service parameters by using the
17130 @code{inherit} feature that @code{define-record-type*} provides.
17132 @xref{Using the Configuration System}, for example usage.
17136 Next comes the programming interface for service types. This is
17137 something you want to know when writing new service definitions, but not
17138 necessarily when simply looking for ways to customize your
17139 @code{operating-system} declaration.
17141 @deftp {Data Type} service-type
17142 @cindex service type
17143 This is the representation of a @dfn{service type} (@pxref{Service Types
17148 This is a symbol, used only to simplify inspection and debugging.
17150 @item @code{extensions}
17151 A non-empty list of @code{<service-extension>} objects (see below).
17153 @item @code{compose} (default: @code{#f})
17154 If this is @code{#f}, then the service type denotes services that cannot
17155 be extended---i.e., services that do not receive ``values'' from other
17158 Otherwise, it must be a one-argument procedure. The procedure is called
17159 by @code{fold-services} and is passed a list of values collected from
17160 extensions. It must return a value that is a valid parameter value for
17161 the service instance.
17163 @item @code{extend} (default: @code{#f})
17164 If this is @code{#f}, services of this type cannot be extended.
17166 Otherwise, it must be a two-argument procedure: @code{fold-services}
17167 calls it, passing it the initial value of the service as the first argument
17168 and the result of applying @code{compose} to the extension values as the
17172 @xref{Service Types and Services}, for examples.
17175 @deffn {Scheme Procedure} service-extension @var{target-type} @
17177 Return a new extension for services of type @var{target-type}.
17178 @var{compute} must be a one-argument procedure: @code{fold-services}
17179 calls it, passing it the value associated with the service that provides
17180 the extension; it must return a valid value for the target service.
17183 @deffn {Scheme Procedure} service-extension? @var{obj}
17184 Return true if @var{obj} is a service extension.
17187 Occasionally, you might want to simply extend an existing service. This
17188 involves creating a new service type and specifying the extension of
17189 interest, which can be verbose; the @code{simple-service} procedure
17190 provides a shorthand for this.
17192 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
17193 Return a service that extends @var{target} with @var{value}. This works
17194 by creating a singleton service type @var{name}, of which the returned
17195 service is an instance.
17197 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
17201 (simple-service 'my-mcron-job mcron-service-type
17202 #~(job '(next-hour (3)) "guix gc -F 2G"))
17206 At the core of the service abstraction lies the @code{fold-services}
17207 procedure, which is responsible for ``compiling'' a list of services
17208 down to a single directory that contains everything needed to boot and
17209 run the system---the directory shown by the @command{guix system build}
17210 command (@pxref{Invoking guix system}). In essence, it propagates
17211 service extensions down the service graph, updating each node parameters
17212 on the way, until it reaches the root node.
17214 @deffn {Scheme Procedure} fold-services @var{services} @
17215 [#:target-type @var{system-service-type}]
17216 Fold @var{services} by propagating their extensions down to the root of
17217 type @var{target-type}; return the root service adjusted accordingly.
17220 Lastly, the @code{(gnu services)} module also defines several essential
17221 service types, some of which are listed below.
17223 @defvr {Scheme Variable} system-service-type
17224 This is the root of the service graph. It produces the system directory
17225 as returned by the @command{guix system build} command.
17228 @defvr {Scheme Variable} boot-service-type
17229 The type of the ``boot service'', which produces the @dfn{boot script}.
17230 The boot script is what the initial RAM disk runs when booting.
17233 @defvr {Scheme Variable} etc-service-type
17234 The type of the @file{/etc} service. This service can be extended by
17235 passing it name/file tuples such as:
17238 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
17241 In this example, the effect would be to add an @file{/etc/issue} file
17242 pointing to the given file.
17245 @defvr {Scheme Variable} setuid-program-service-type
17246 Type for the ``setuid-program service''. This service collects lists of
17247 executable file names, passed as gexps, and adds them to the set of
17248 setuid-root programs on the system (@pxref{Setuid Programs}).
17251 @defvr {Scheme Variable} profile-service-type
17252 Type of the service that populates the @dfn{system profile}---i.e., the
17253 programs under @file{/run/current-system/profile}. Other services can
17254 extend it by passing it lists of packages to add to the system profile.
17258 @node Shepherd Services
17259 @subsubsection Shepherd Services
17261 @cindex shepherd services
17263 @cindex init system
17264 The @code{(gnu services shepherd)} module provides a way to define
17265 services managed by the GNU@tie{}Shepherd, which is the GuixSD
17266 initialization system---the first process that is started when the
17267 system boots, also known as PID@tie{}1
17268 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
17270 Services in the Shepherd can depend on each other. For instance, the
17271 SSH daemon may need to be started after the syslog daemon has been
17272 started, which in turn can only happen once all the file systems have
17273 been mounted. The simple operating system defined earlier (@pxref{Using
17274 the Configuration System}) results in a service graph like this:
17276 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
17278 You can actually generate such a graph for any operating system
17279 definition using the @command{guix system shepherd-graph} command
17280 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
17282 The @var{%shepherd-root-service} is a service object representing
17283 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
17284 by passing it lists of @code{<shepherd-service>} objects.
17286 @deftp {Data Type} shepherd-service
17287 The data type representing a service managed by the Shepherd.
17290 @item @code{provision}
17291 This is a list of symbols denoting what the service provides.
17293 These are the names that may be passed to @command{herd start},
17294 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
17295 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
17296 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
17298 @item @code{requirements} (default: @code{'()})
17299 List of symbols denoting the Shepherd services this one depends on.
17301 @item @code{respawn?} (default: @code{#t})
17302 Whether to restart the service when it stops, for instance when the
17303 underlying process dies.
17306 @itemx @code{stop} (default: @code{#~(const #f)})
17307 The @code{start} and @code{stop} fields refer to the Shepherd's
17308 facilities to start and stop processes (@pxref{Service De- and
17309 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
17310 G-expressions that get expanded in the Shepherd configuration file
17311 (@pxref{G-Expressions}).
17313 @item @code{documentation}
17314 A documentation string, as shown when running:
17317 herd doc @var{service-name}
17320 where @var{service-name} is one of the symbols in @var{provision}
17321 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
17323 @item @code{modules} (default: @var{%default-modules})
17324 This is the list of modules that must be in scope when @code{start} and
17325 @code{stop} are evaluated.
17330 @defvr {Scheme Variable} shepherd-root-service-type
17331 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
17333 This is the service type that extensions target when they want to create
17334 shepherd services (@pxref{Service Types and Services}, for an example).
17335 Each extension must pass a list of @code{<shepherd-service>}.
17338 @defvr {Scheme Variable} %shepherd-root-service
17339 This service represents PID@tie{}1.
17343 @node Documentation
17344 @section Documentation
17346 @cindex documentation, searching for
17347 @cindex searching for documentation
17348 @cindex Info, documentation format
17350 @cindex manual pages
17351 In most cases packages installed with Guix come with documentation.
17352 There are two main documentation formats: ``Info'', a browseable
17353 hypertext format used for GNU software, and ``manual pages'' (or ``man
17354 pages''), the linear documentation format traditionally found on Unix.
17355 Info manuals are accessed with the @command{info} command or with Emacs,
17356 and man pages are accessed using @command{man}.
17358 You can look for documentation of software installed on your system by
17359 keyword. For example, the following command searches for information
17360 about ``TLS'' in Info manuals:
17364 "(emacs)Network Security" -- STARTTLS
17365 "(emacs)Network Security" -- TLS
17366 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
17367 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
17372 The command below searches for the same keyword in man pages:
17376 SSL (7) - OpenSSL SSL/TLS library
17377 certtool (1) - GnuTLS certificate tool
17381 These searches are purely local to your computer so you have the
17382 guarantee that documentation you find corresponds to what you have
17383 actually installed, you can access it off-line, and your privacy is
17386 Once you have these results, you can view the relevant documentation by
17390 $ info "(gnutls)Core TLS API"
17400 Info manuals contain sections and indices as well as hyperlinks like
17401 those found in Web pages. The @command{info} reader (@pxref{Top, Info
17402 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
17403 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
17404 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
17405 Introduction}, for an introduction to Info navigation.
17407 @node Installing Debugging Files
17408 @section Installing Debugging Files
17410 @cindex debugging files
17411 Program binaries, as produced by the GCC compilers for instance, are
17412 typically written in the ELF format, with a section containing
17413 @dfn{debugging information}. Debugging information is what allows the
17414 debugger, GDB, to map binary code to source code; it is required to
17415 debug a compiled program in good conditions.
17417 The problem with debugging information is that is takes up a fair amount
17418 of disk space. For example, debugging information for the GNU C Library
17419 weighs in at more than 60 MiB. Thus, as a user, keeping all the
17420 debugging info of all the installed programs is usually not an option.
17421 Yet, space savings should not come at the cost of an impediment to
17422 debugging---especially in the GNU system, which should make it easier
17423 for users to exert their computing freedom (@pxref{GNU Distribution}).
17425 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
17426 mechanism that allows users to get the best of both worlds: debugging
17427 information can be stripped from the binaries and stored in separate
17428 files. GDB is then able to load debugging information from those files,
17429 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
17432 The GNU distribution takes advantage of this by storing debugging
17433 information in the @code{lib/debug} sub-directory of a separate package
17434 output unimaginatively called @code{debug} (@pxref{Packages with
17435 Multiple Outputs}). Users can choose to install the @code{debug} output
17436 of a package when they need it. For instance, the following command
17437 installs the debugging information for the GNU C Library and for GNU
17441 guix package -i glibc:debug guile:debug
17444 GDB must then be told to look for debug files in the user's profile, by
17445 setting the @code{debug-file-directory} variable (consider setting it
17446 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
17450 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
17453 From there on, GDB will pick up debugging information from the
17454 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
17456 In addition, you will most likely want GDB to be able to show the source
17457 code being debugged. To do that, you will have to unpack the source
17458 code of the package of interest (obtained with @code{guix build
17459 --source}, @pxref{Invoking guix build}), and to point GDB to that source
17460 directory using the @code{directory} command (@pxref{Source Path,
17461 @code{directory},, gdb, Debugging with GDB}).
17463 @c XXX: keep me up-to-date
17464 The @code{debug} output mechanism in Guix is implemented by the
17465 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
17466 opt-in---debugging information is available only for the packages
17467 with definitions explicitly declaring a @code{debug} output. This may be
17468 changed to opt-out in the future if our build farm servers can handle
17469 the load. To check whether a package has a @code{debug} output, use
17470 @command{guix package --list-available} (@pxref{Invoking guix package}).
17473 @node Security Updates
17474 @section Security Updates
17476 @cindex security updates
17477 @cindex security vulnerabilities
17478 Occasionally, important security vulnerabilities are discovered in software
17479 packages and must be patched. Guix developers try hard to keep track of
17480 known vulnerabilities and to apply fixes as soon as possible in the
17481 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
17482 containing only security updates.) The @command{guix lint} tool helps
17483 developers find out about vulnerable versions of software packages in the
17488 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
17489 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
17490 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
17494 @xref{Invoking guix lint}, for more information.
17497 As of version @value{VERSION}, the feature described below is considered
17501 Guix follows a functional
17502 package management discipline (@pxref{Introduction}), which implies
17503 that, when a package is changed, @emph{every package that depends on it}
17504 must be rebuilt. This can significantly slow down the deployment of
17505 fixes in core packages such as libc or Bash, since basically the whole
17506 distribution would need to be rebuilt. Using pre-built binaries helps
17507 (@pxref{Substitutes}), but deployment may still take more time than
17511 To address this, Guix implements @dfn{grafts}, a mechanism that allows
17512 for fast deployment of critical updates without the costs associated
17513 with a whole-distribution rebuild. The idea is to rebuild only the
17514 package that needs to be patched, and then to ``graft'' it onto packages
17515 explicitly installed by the user and that were previously referring to
17516 the original package. The cost of grafting is typically very low, and
17517 order of magnitudes lower than a full rebuild of the dependency chain.
17519 @cindex replacements of packages, for grafts
17520 For instance, suppose a security update needs to be applied to Bash.
17521 Guix developers will provide a package definition for the ``fixed''
17522 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
17523 Packages}). Then, the original package definition is augmented with a
17524 @code{replacement} field pointing to the package containing the bug fix:
17531 (replacement bash-fixed)))
17534 From there on, any package depending directly or indirectly on Bash---as
17535 reported by @command{guix gc --requisites} (@pxref{Invoking guix
17536 gc})---that is installed is automatically ``rewritten'' to refer to
17537 @var{bash-fixed} instead of @var{bash}. This grafting process takes
17538 time proportional to the size of the package, usually less than a
17539 minute for an ``average'' package on a recent machine. Grafting is
17540 recursive: when an indirect dependency requires grafting, then grafting
17541 ``propagates'' up to the package that the user is installing.
17543 Currently, the length of the name and version of the graft and that of
17544 the package it replaces (@var{bash-fixed} and @var{bash} in the example
17545 above) must be equal. This restriction mostly comes from the fact that
17546 grafting works by patching files, including binary files, directly.
17547 Other restrictions may apply: for instance, when adding a graft to a
17548 package providing a shared library, the original shared library and its
17549 replacement must have the same @code{SONAME} and be binary-compatible.
17551 The @option{--no-grafts} command-line option allows you to forcefully
17552 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
17556 guix build bash --no-grafts
17560 returns the store file name of the original Bash, whereas:
17567 returns the store file name of the ``fixed'', replacement Bash. This
17568 allows you to distinguish between the two variants of Bash.
17570 To verify which Bash your whole profile refers to, you can run
17571 (@pxref{Invoking guix gc}):
17574 guix gc -R `readlink -f ~/.guix-profile` | grep bash
17578 @dots{} and compare the store file names that you get with those above.
17579 Likewise for a complete GuixSD system generation:
17582 guix gc -R `guix system build my-config.scm` | grep bash
17585 Lastly, to check which Bash running processes are using, you can use the
17586 @command{lsof} command:
17589 lsof | grep /gnu/store/.*bash
17593 @node Package Modules
17594 @section Package Modules
17596 From a programming viewpoint, the package definitions of the
17597 GNU distribution are provided by Guile modules in the @code{(gnu packages
17598 @dots{})} name space@footnote{Note that packages under the @code{(gnu
17599 packages @dots{})} module name space are not necessarily ``GNU
17600 packages''. This module naming scheme follows the usual Guile module
17601 naming convention: @code{gnu} means that these modules are distributed
17602 as part of the GNU system, and @code{packages} identifies modules that
17603 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
17604 Reference Manual}). For instance, the @code{(gnu packages emacs)}
17605 module exports a variable named @code{emacs}, which is bound to a
17606 @code{<package>} object (@pxref{Defining Packages}).
17608 The @code{(gnu packages @dots{})} module name space is
17609 automatically scanned for packages by the command-line tools. For
17610 instance, when running @code{guix package -i emacs}, all the @code{(gnu
17611 packages @dots{})} modules are scanned until one that exports a package
17612 object whose name is @code{emacs} is found. This package search
17613 facility is implemented in the @code{(gnu packages)} module.
17615 @cindex customization, of packages
17616 @cindex package module search path
17617 Users can store package definitions in modules with different
17618 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
17619 name and module name must match. For instance, the @code{(my-packages
17620 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
17621 relative to the load path specified with @option{--load-path} or
17622 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
17623 guile, GNU Guile Reference Manual}, for details.}. These package definitions
17624 will not be visible by default. Users can invoke commands such as
17625 @command{guix package} and @command{guix build} with the
17626 @code{-e} option so that they know where to find the package. Better
17627 yet, they can use the
17628 @code{-L} option of these commands to make those modules visible
17629 (@pxref{Invoking guix build, @code{--load-path}}), or define the
17630 @code{GUIX_PACKAGE_PATH} environment variable. This environment
17631 variable makes it easy to extend or customize the distribution and is
17632 honored by all the user interfaces.
17634 @defvr {Environment Variable} GUIX_PACKAGE_PATH
17635 This is a colon-separated list of directories to search for additional
17636 package modules. Directories listed in this variable take precedence
17637 over the own modules of the distribution.
17640 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
17641 each package is built based solely on other packages in the
17642 distribution. The root of this dependency graph is a small set of
17643 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
17644 bootstrap)} module. For more information on bootstrapping,
17645 @pxref{Bootstrapping}.
17647 @node Packaging Guidelines
17648 @section Packaging Guidelines
17650 @cindex packages, creating
17651 The GNU distribution is nascent and may well lack some of your favorite
17652 packages. This section describes how you can help make the distribution
17653 grow. @xref{Contributing}, for additional information on how you can
17656 Free software packages are usually distributed in the form of
17657 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
17658 all the source files. Adding a package to the distribution means
17659 essentially two things: adding a @dfn{recipe} that describes how to
17660 build the package, including a list of other packages required to build
17661 it, and adding @dfn{package metadata} along with that recipe, such as a
17662 description and licensing information.
17664 In Guix all this information is embodied in @dfn{package definitions}.
17665 Package definitions provide a high-level view of the package. They are
17666 written using the syntax of the Scheme programming language; in fact,
17667 for each package we define a variable bound to the package definition,
17668 and export that variable from a module (@pxref{Package Modules}).
17669 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
17670 creating packages. For more information on package definitions,
17671 @pxref{Defining Packages}.
17673 Once a package definition is in place, stored in a file in the Guix
17674 source tree, it can be tested using the @command{guix build} command
17675 (@pxref{Invoking guix build}). For example, assuming the new package is
17676 called @code{gnew}, you may run this command from the Guix build tree
17677 (@pxref{Running Guix Before It Is Installed}):
17680 ./pre-inst-env guix build gnew --keep-failed
17683 Using @code{--keep-failed} makes it easier to debug build failures since
17684 it provides access to the failed build tree. Another useful
17685 command-line option when debugging is @code{--log-file}, to access the
17688 If the package is unknown to the @command{guix} command, it may be that
17689 the source file contains a syntax error, or lacks a @code{define-public}
17690 clause to export the package variable. To figure it out, you may load
17691 the module from Guile to get more information about the actual error:
17694 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
17697 Once your package builds correctly, please send us a patch
17698 (@pxref{Contributing}). Well, if you need help, we will be happy to
17699 help you too. Once the patch is committed in the Guix repository, the
17700 new package automatically gets built on the supported platforms by
17701 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
17704 @cindex substituter
17705 Users can obtain the new package definition simply by running
17706 @command{guix pull} (@pxref{Invoking guix pull}). When
17707 @code{hydra.gnu.org} is done building the package, installing the
17708 package automatically downloads binaries from there
17709 (@pxref{Substitutes}). The only place where human intervention is
17710 needed is to review and apply the patch.
17714 * Software Freedom:: What may go into the distribution.
17715 * Package Naming:: What's in a name?
17716 * Version Numbers:: When the name is not enough.
17717 * Synopses and Descriptions:: Helping users find the right package.
17718 * Python Modules:: A touch of British comedy.
17719 * Perl Modules:: Little pearls.
17720 * Java Packages:: Coffee break.
17721 * Fonts:: Fond of fonts.
17724 @node Software Freedom
17725 @subsection Software Freedom
17727 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
17728 @cindex free software
17729 The GNU operating system has been developed so that users can have
17730 freedom in their computing. GNU is @dfn{free software}, meaning that
17731 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
17732 essential freedoms}: to run the program, to study and change the program
17733 in source code form, to redistribute exact copies, and to distribute
17734 modified versions. Packages found in the GNU distribution provide only
17735 software that conveys these four freedoms.
17737 In addition, the GNU distribution follow the
17738 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
17739 software distribution guidelines}. Among other things, these guidelines
17740 reject non-free firmware, recommendations of non-free software, and
17741 discuss ways to deal with trademarks and patents.
17743 Some otherwise free upstream package sources contain a small and optional
17744 subset that violates the above guidelines, for instance because this subset
17745 is itself non-free code. When that happens, the offending items are removed
17746 with appropriate patches or code snippets in the @code{origin} form of the
17747 package (@pxref{Defining Packages}). This way, @code{guix
17748 build --source} returns the ``freed'' source rather than the unmodified
17752 @node Package Naming
17753 @subsection Package Naming
17755 @cindex package name
17756 A package has actually two names associated with it:
17757 First, there is the name of the @emph{Scheme variable}, the one following
17758 @code{define-public}. By this name, the package can be made known in the
17759 Scheme code, for instance as input to another package. Second, there is
17760 the string in the @code{name} field of a package definition. This name
17761 is used by package management commands such as
17762 @command{guix package} and @command{guix build}.
17764 Both are usually the same and correspond to the lowercase conversion of
17765 the project name chosen upstream, with underscores replaced with
17766 hyphens. For instance, GNUnet is available as @code{gnunet}, and
17767 SDL_net as @code{sdl-net}.
17769 We do not add @code{lib} prefixes for library packages, unless these are
17770 already part of the official project name. But @pxref{Python
17771 Modules} and @ref{Perl Modules} for special rules concerning modules for
17772 the Python and Perl languages.
17774 Font package names are handled differently, @pxref{Fonts}.
17777 @node Version Numbers
17778 @subsection Version Numbers
17780 @cindex package version
17781 We usually package only the latest version of a given free software
17782 project. But sometimes, for instance for incompatible library versions,
17783 two (or more) versions of the same package are needed. These require
17784 different Scheme variable names. We use the name as defined
17785 in @ref{Package Naming}
17786 for the most recent version; previous versions use the same name, suffixed
17787 by @code{-} and the smallest prefix of the version number that may
17788 distinguish the two versions.
17790 The name inside the package definition is the same for all versions of a
17791 package and does not contain any version number.
17793 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
17796 (define-public gtk+
17801 (define-public gtk+-2
17804 (version "2.24.20")
17807 If we also wanted GTK+ 3.8.2, this would be packaged as
17809 (define-public gtk+-3.8
17816 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
17817 @c for a discussion of what follows.
17818 @cindex version number, for VCS snapshots
17819 Occasionally, we package snapshots of upstream's version control system
17820 (VCS) instead of formal releases. This should remain exceptional,
17821 because it is up to upstream developers to clarify what the stable
17822 release is. Yet, it is sometimes necessary. So, what should we put in
17823 the @code{version} field?
17825 Clearly, we need to make the commit identifier of the VCS snapshot
17826 visible in the version string, but we also need to make sure that the
17827 version string is monotonically increasing so that @command{guix package
17828 --upgrade} can determine which version is newer. Since commit
17829 identifiers, notably with Git, are not monotonically increasing, we add
17830 a revision number that we increase each time we upgrade to a newer
17831 snapshot. The resulting version string looks like this:
17836 | | `-- upstream commit ID
17838 | `--- Guix package revision
17840 latest upstream version
17843 It is a good idea to strip commit identifiers in the @code{version}
17844 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
17845 aesthetics have a role to play here) as well as problems related to OS
17846 limits such as the maximum shebang length (127 bytes for the Linux
17847 kernel.) It is best to use the full commit identifiers in
17848 @code{origin}s, though, to avoid ambiguities. A typical package
17849 definition may look like this:
17853 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
17854 (revision "1")) ;Guix package revision
17856 (version (string-append "0.9-" revision "."
17857 (string-take commit 7)))
17860 (uri (git-reference
17861 (url "git://example.org/my-package.git")
17863 (sha256 (base32 "1mbikn@dots{}"))
17864 (file-name (string-append "my-package-" version
17870 @node Synopses and Descriptions
17871 @subsection Synopses and Descriptions
17873 @cindex package description
17874 @cindex package synopsis
17875 As we have seen before, each package in GNU@tie{}Guix includes a
17876 synopsis and a description (@pxref{Defining Packages}). Synopses and
17877 descriptions are important: They are what @command{guix package
17878 --search} searches, and a crucial piece of information to help users
17879 determine whether a given package suits their needs. Consequently,
17880 packagers should pay attention to what goes into them.
17882 Synopses must start with a capital letter and must not end with a
17883 period. They must not start with ``a'' or ``the'', which usually does
17884 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
17885 tool that frobs files''. The synopsis should say what the package
17886 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
17887 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
17888 matching a pattern''.
17890 Keep in mind that the synopsis must be meaningful for a very wide
17891 audience. For example, ``Manipulate alignments in the SAM format''
17892 might make sense for a seasoned bioinformatics researcher, but might be
17893 fairly unhelpful or even misleading to a non-specialized audience. It
17894 is a good idea to come up with a synopsis that gives an idea of the
17895 application domain of the package. In this example, this might give
17896 something like ``Manipulate nucleotide sequence alignments'', which
17897 hopefully gives the user a better idea of whether this is what they are
17900 Descriptions should take between five and ten lines. Use full
17901 sentences, and avoid using acronyms without first introducing them.
17902 Please avoid marketing phrases such as ``world-leading'',
17903 ``industrial-strength'', and ``next-generation'', and avoid superlatives
17904 like ``the most advanced''---they are not helpful to users looking for a
17905 package and may even sound suspicious. Instead, try to be factual,
17906 mentioning use cases and features.
17908 @cindex Texinfo markup, in package descriptions
17909 Descriptions can include Texinfo markup, which is useful to introduce
17910 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
17911 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
17912 should be careful when using some characters for example @samp{@@} and
17913 curly braces which are the basic special characters in Texinfo
17914 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
17915 such as @command{guix package --show} take care of rendering it
17918 Synopses and descriptions are translated by volunteers
17919 @uref{http://translationproject.org/domain/guix-packages.html, at the
17920 Translation Project} so that as many users as possible can read them in
17921 their native language. User interfaces search them and display them in
17922 the language specified by the current locale.
17924 Translation is a lot of work so, as a packager, please pay even more
17925 attention to your synopses and descriptions as every change may entail
17926 additional work for translators. In order to help them, it is possible
17927 to make recommendations or instructions visible to them by inserting
17928 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
17932 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
17933 (description "ARandR is designed to provide a simple visual front end
17934 for the X11 resize-and-rotate (RandR) extension. @dots{}")
17938 @node Python Modules
17939 @subsection Python Modules
17942 We currently package Python 2 and Python 3, under the Scheme variable names
17943 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
17944 To avoid confusion and naming clashes with other programming languages, it
17945 seems desirable that the name of a package for a Python module contains
17946 the word @code{python}.
17948 Some modules are compatible with only one version of Python, others with both.
17949 If the package Foo compiles only with Python 3, we name it
17950 @code{python-foo}; if it compiles only with Python 2, we name it
17951 @code{python2-foo}. If it is compatible with both versions, we create two
17952 packages with the corresponding names.
17954 If a project already contains the word @code{python}, we drop this;
17955 for instance, the module python-dateutil is packaged under the names
17956 @code{python-dateutil} and @code{python2-dateutil}. If the project name
17957 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
17960 @subsubsection Specifying Dependencies
17961 @cindex inputs, for Python packages
17963 Dependency information for Python packages is usually available in the
17964 package source tree, with varying degrees of accuracy: in the
17965 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
17967 Your mission, when writing a recipe for a Python package, is to map
17968 these dependencies to the appropriate type of ``input'' (@pxref{package
17969 Reference, inputs}). Although the @code{pypi} importer normally does a
17970 good job (@pxref{Invoking guix import}), you may want to check the
17971 following check list to determine which dependency goes where.
17976 We currently package Python 2 with @code{setuptools} and @code{pip}
17977 installed like Python 3.4 has per default. Thus you don't need to
17978 specify either of these as an input. @command{guix lint} will warn you
17982 Python dependencies required at run time go into
17983 @code{propagated-inputs}. They are typically defined with the
17984 @code{install_requires} keyword in @file{setup.py}, or in the
17985 @file{requirements.txt} file.
17988 Python packages required only at build time---e.g., those listed with
17989 the @code{setup_requires} keyword in @file{setup.py}---or only for
17990 testing---e.g., those in @code{tests_require}---go into
17991 @code{native-inputs}. The rationale is that (1) they do not need to be
17992 propagated because they are not needed at run time, and (2) in a
17993 cross-compilation context, it's the ``native'' input that we'd want.
17995 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
17996 frameworks. Of course if any of these packages is also required at
17997 run-time, it needs to go to @code{propagated-inputs}.
18000 Anything that does not fall in the previous categories goes to
18001 @code{inputs}, for example programs or C libraries required for building
18002 Python packages containing C extensions.
18005 If a Python package has optional dependencies (@code{extras_require}),
18006 it is up to you to decide whether to add them or not, based on their
18007 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
18014 @subsection Perl Modules
18017 Perl programs standing for themselves are named as any other package,
18018 using the lowercase upstream name.
18019 For Perl packages containing a single class, we use the lowercase class name,
18020 replace all occurrences of @code{::} by dashes and prepend the prefix
18022 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
18023 Modules containing several classes keep their lowercase upstream name and
18024 are also prepended by @code{perl-}. Such modules tend to have the word
18025 @code{perl} somewhere in their name, which gets dropped in favor of the
18026 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
18029 @node Java Packages
18030 @subsection Java Packages
18033 Java programs standing for themselves are named as any other package,
18034 using the lowercase upstream name.
18036 To avoid confusion and naming clashes with other programming languages,
18037 it is desirable that the name of a package for a Java package is
18038 prefixed with @code{java-}. If a project already contains the word
18039 @code{java}, we drop this; for instance, the package @code{ngsjava} is
18040 packaged under the name @code{java-ngs}.
18042 For Java packages containing a single class or a small class hierarchy,
18043 we use the lowercase class name, replace all occurrences of @code{.} by
18044 dashes and prepend the prefix @code{java-}. So the class
18045 @code{apache.commons.cli} becomes package
18046 @code{java-apache-commons-cli}.
18053 For fonts that are in general not installed by a user for typesetting
18054 purposes, or that are distributed as part of a larger software package,
18055 we rely on the general packaging rules for software; for instance, this
18056 applies to the fonts delivered as part of the X.Org system or fonts that
18057 are part of TeX Live.
18059 To make it easier for a user to search for fonts, names for other packages
18060 containing only fonts are constructed as follows, independently of the
18061 upstream package name.
18063 The name of a package containing only one font family starts with
18064 @code{font-}; it is followed by the foundry name and a dash @code{-}
18065 if the foundry is known, and the font family name, in which spaces are
18066 replaced by dashes (and as usual, all upper case letters are transformed
18068 For example, the Gentium font family by SIL is packaged under the name
18069 @code{font-sil-gentium}.
18071 For a package containing several font families, the name of the collection
18072 is used in the place of the font family name.
18073 For instance, the Liberation fonts consist of three families,
18074 Liberation Sans, Liberation Serif and Liberation Mono.
18075 These could be packaged separately under the names
18076 @code{font-liberation-sans} and so on; but as they are distributed together
18077 under a common name, we prefer to package them together as
18078 @code{font-liberation}.
18080 In the case where several formats of the same font family or font collection
18081 are packaged separately, a short form of the format, prepended by a dash,
18082 is added to the package name. We use @code{-ttf} for TrueType fonts,
18083 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
18088 @node Bootstrapping
18089 @section Bootstrapping
18091 @c Adapted from the ELS 2013 paper.
18093 @cindex bootstrapping
18095 Bootstrapping in our context refers to how the distribution gets built
18096 ``from nothing''. Remember that the build environment of a derivation
18097 contains nothing but its declared inputs (@pxref{Introduction}). So
18098 there's an obvious chicken-and-egg problem: how does the first package
18099 get built? How does the first compiler get compiled? Note that this is
18100 a question of interest only to the curious hacker, not to the regular
18101 user, so you can shamelessly skip this section if you consider yourself
18102 a ``regular user''.
18104 @cindex bootstrap binaries
18105 The GNU system is primarily made of C code, with libc at its core. The
18106 GNU build system itself assumes the availability of a Bourne shell and
18107 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
18108 `grep'. Furthermore, build programs---programs that run
18109 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
18110 (@pxref{Derivations}). Consequently, to be able to build anything at
18111 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
18112 Binutils, libc, and the other packages mentioned above---the
18113 @dfn{bootstrap binaries}.
18115 These bootstrap binaries are ``taken for granted'', though we can also
18116 re-create them if needed (more on that later).
18118 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
18120 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
18121 @c large image, it's hard to scroll. Oh well.
18122 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
18124 The figure above shows the very beginning of the dependency graph of the
18125 distribution, corresponding to the package definitions of the @code{(gnu
18126 packages bootstrap)} module. A similar figure can be generated with
18127 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
18130 guix graph -t derivation \
18131 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
18135 At this level of detail, things are
18136 slightly complex. First, Guile itself consists of an ELF executable,
18137 along with many source and compiled Scheme files that are dynamically
18138 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
18139 tarball shown in this graph. This tarball is part of Guix's ``source''
18140 distribution, and gets inserted into the store with @code{add-to-store}
18141 (@pxref{The Store}).
18143 But how do we write a derivation that unpacks this tarball and adds it
18144 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
18145 derivation---the first one that gets built---uses @code{bash} as its
18146 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
18147 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
18148 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
18149 the Guix source distribution, whose sole purpose is to allow the Guile
18150 tarball to be unpacked.
18152 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
18153 Guile that can be used to run subsequent build programs. Its first task
18154 is to download tarballs containing the other pre-built binaries---this
18155 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
18156 @code{ftp-client.scm} are used for this purpose. The
18157 @code{module-import.drv} derivations import those modules in a directory
18158 in the store, using the original layout. The
18159 @code{module-import-compiled.drv} derivations compile those modules, and
18160 write them in an output directory with the right layout. This
18161 corresponds to the @code{#:modules} argument of
18162 @code{build-expression->derivation} (@pxref{Derivations}).
18164 Finally, the various tarballs are unpacked by the
18165 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
18166 etc., at which point we have a working C tool chain.
18169 @unnumberedsubsec Building the Build Tools
18171 Bootstrapping is complete when we have a full tool chain that does not
18172 depend on the pre-built bootstrap tools discussed above. This
18173 no-dependency requirement is verified by checking whether the files of
18174 the final tool chain contain references to the @file{/gnu/store}
18175 directories of the bootstrap inputs. The process that leads to this
18176 ``final'' tool chain is described by the package definitions found in
18177 the @code{(gnu packages commencement)} module.
18179 The @command{guix graph} command allows us to ``zoom out'' compared to
18180 the graph above, by looking at the level of package objects instead of
18181 individual derivations---remember that a package may translate to
18182 several derivations, typically one derivation to download its source,
18183 one to build the Guile modules it needs, and one to actually build the
18184 package from source. The command:
18187 guix graph -t bag \
18188 -e '(@@@@ (gnu packages commencement)
18189 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
18193 produces the dependency graph leading to the ``final'' C
18194 library@footnote{You may notice the @code{glibc-intermediate} label,
18195 suggesting that it is not @emph{quite} final, but as a good
18196 approximation, we will consider it final.}, depicted below.
18198 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
18200 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
18201 The first tool that gets built with the bootstrap binaries is
18202 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
18203 for all the following packages. From there Findutils and Diffutils get
18206 Then come the first-stage Binutils and GCC, built as pseudo cross
18207 tools---i.e., with @code{--target} equal to @code{--host}. They are
18208 used to build libc. Thanks to this cross-build trick, this libc is
18209 guaranteed not to hold any reference to the initial tool chain.
18211 From there the final Binutils and GCC (not shown above) are built.
18213 from the final Binutils, and links programs against the just-built libc.
18214 This tool chain is used to build the other packages used by Guix and by
18215 the GNU Build System: Guile, Bash, Coreutils, etc.
18217 And voilà! At this point we have the complete set of build tools that
18218 the GNU Build System expects. These are in the @code{%final-inputs}
18219 variable of the @code{(gnu packages commencement)} module, and are
18220 implicitly used by any package that uses @code{gnu-build-system}
18221 (@pxref{Build Systems, @code{gnu-build-system}}).
18224 @unnumberedsubsec Building the Bootstrap Binaries
18226 @cindex bootstrap binaries
18227 Because the final tool chain does not depend on the bootstrap binaries,
18228 those rarely need to be updated. Nevertheless, it is useful to have an
18229 automated way to produce them, should an update occur, and this is what
18230 the @code{(gnu packages make-bootstrap)} module provides.
18232 The following command builds the tarballs containing the bootstrap
18233 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
18234 of Coreutils and other basic command-line tools):
18237 guix build bootstrap-tarballs
18240 The generated tarballs are those that should be referred to in the
18241 @code{(gnu packages bootstrap)} module mentioned at the beginning of
18244 Still here? Then perhaps by now you've started to wonder: when do we
18245 reach a fixed point? That is an interesting question! The answer is
18246 unknown, but if you would like to investigate further (and have
18247 significant computational and storage resources to do so), then let us
18251 @section Porting to a New Platform
18253 As discussed above, the GNU distribution is self-contained, and
18254 self-containment is achieved by relying on pre-built ``bootstrap
18255 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
18256 operating system kernel, CPU architecture, and application binary
18257 interface (ABI). Thus, to port the distribution to a platform that is
18258 not yet supported, one must build those bootstrap binaries, and update
18259 the @code{(gnu packages bootstrap)} module to use them on that platform.
18261 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
18262 When everything goes well, and assuming the GNU tool chain supports the
18263 target platform, this can be as simple as running a command like this
18267 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
18270 For this to work, the @code{glibc-dynamic-linker} procedure in
18271 @code{(gnu packages bootstrap)} must be augmented to return the right
18272 file name for libc's dynamic linker on that platform; likewise,
18273 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
18274 taught about the new platform.
18276 Once these are built, the @code{(gnu packages bootstrap)} module needs
18277 to be updated to refer to these binaries on the target platform. That
18278 is, the hashes and URLs of the bootstrap tarballs for the new platform
18279 must be added alongside those of the currently supported platforms. The
18280 bootstrap Guile tarball is treated specially: it is expected to be
18281 available locally, and @file{gnu/local.mk} has rules do download it for
18282 the supported architectures; a rule for the new platform must be added
18285 In practice, there may be some complications. First, it may be that the
18286 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
18287 above) is not recognized by all the GNU tools. Typically, glibc
18288 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
18289 configure flag (see @code{gcc.scm} for examples of how to handle this).
18290 Second, some of the required packages could fail to build for that
18291 platform. Lastly, the generated binaries could be broken for some
18294 @c *********************************************************************
18295 @include contributing.texi
18297 @c *********************************************************************
18298 @node Acknowledgments
18299 @chapter Acknowledgments
18301 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
18302 which was designed and
18303 implemented by Eelco Dolstra, with contributions from other people (see
18304 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
18305 management, and promoted unprecedented features, such as transactional
18306 package upgrades and rollbacks, per-user profiles, and referentially
18307 transparent build processes. Without this work, Guix would not exist.
18309 The Nix-based software distributions, Nixpkgs and NixOS, have also been
18310 an inspiration for Guix.
18312 GNU@tie{}Guix itself is a collective work with contributions from a
18313 number of people. See the @file{AUTHORS} file in Guix for more
18314 information on these fine people. The @file{THANKS} file lists people
18315 who have helped by reporting bugs, taking care of the infrastructure,
18316 providing artwork and themes, making suggestions, and more---thank you!
18319 @c *********************************************************************
18320 @node GNU Free Documentation License
18321 @appendix GNU Free Documentation License
18322 @cindex license, GNU Free Documentation License
18323 @include fdl-1.3.texi
18325 @c *********************************************************************
18326 @node Concept Index
18327 @unnumbered Concept Index
18330 @node Programming Index
18331 @unnumbered Programming Index
18332 @syncodeindex tp fn
18333 @syncodeindex vr fn
18338 @c Local Variables:
18339 @c ispell-local-dictionary: "american";