6 @documentencoding UTF-8
7 @settitle GNU Guix Reference Manual
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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 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
42 Permission is granted to copy, distribute and/or modify this document
43 under the terms of the GNU Free Documentation License, Version 1.3 or
44 any later version published by the Free Software Foundation; with no
45 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
46 copy of the license is included in the section entitled ``GNU Free
47 Documentation License''.
50 @dircategory System administration
52 * Guix: (guix). Manage installed software and system configuration.
53 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
54 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
55 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
56 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
59 @dircategory Software development
61 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
62 * guix build: (guix)Invoking guix build. Building packages.
63 * guix pack: (guix)Invoking guix pack. Creating binary bundles.
67 @title GNU Guix Reference Manual
68 @subtitle Using the GNU Guix Functional Package Manager
69 @author The GNU Guix Developers
72 @vskip 0pt plus 1filll
73 Edition @value{EDITION} @*
81 @c *********************************************************************
85 This document describes GNU Guix version @value{VERSION}, a functional
86 package management tool written for the GNU system.
89 * Introduction:: What is Guix about?
90 * Installation:: Installing Guix.
91 * Package Management:: Package installation, upgrade, etc.
92 * Programming Interface:: Using Guix in Scheme.
93 * Utilities:: Package management commands.
94 * GNU Distribution:: Software for your friendly GNU system.
95 * Contributing:: Your help needed!
97 * Acknowledgments:: Thanks!
98 * GNU Free Documentation License:: The license of this manual.
99 * Concept Index:: Concepts.
100 * Programming Index:: Data types, functions, and variables.
103 --- The Detailed Node Listing ---
107 * Binary Installation:: Getting Guix running in no time!
108 * Requirements:: Software needed to build and run Guix.
109 * Running the Test Suite:: Testing Guix.
110 * Setting Up the Daemon:: Preparing the build daemon's environment.
111 * Invoking guix-daemon:: Running the build daemon.
112 * Application Setup:: Application-specific setup.
114 Setting Up the Daemon
116 * Build Environment Setup:: Preparing the isolated build environment.
117 * Daemon Offload Setup:: Offloading builds to remote machines.
121 * Features:: How Guix will make your life brighter.
122 * Invoking guix package:: Package installation, removal, etc.
123 * Substitutes:: Downloading pre-built binaries.
124 * Packages with Multiple Outputs:: Single source package, multiple outputs.
125 * Invoking guix gc:: Running the garbage collector.
126 * Invoking guix pull:: Fetching the latest Guix and distribution.
127 * Invoking guix pack:: Creating software bundles.
128 * Invoking guix archive:: Exporting and importing store files.
130 Programming Interface
132 * Defining Packages:: Defining new packages.
133 * Build Systems:: Specifying how packages are built.
134 * The Store:: Manipulating the package store.
135 * Derivations:: Low-level interface to package derivations.
136 * The Store Monad:: Purely functional interface to the store.
137 * G-Expressions:: Manipulating build expressions.
141 * package Reference:: The package data type.
142 * origin Reference:: The origin data type.
146 * Invoking guix build:: Building packages from the command line.
147 * Invoking guix edit:: Editing package definitions.
148 * Invoking guix download:: Downloading a file and printing its hash.
149 * Invoking guix hash:: Computing the cryptographic hash of a file.
150 * Invoking guix import:: Importing package definitions.
151 * Invoking guix refresh:: Updating package definitions.
152 * Invoking guix lint:: Finding errors in package definitions.
153 * Invoking guix size:: Profiling disk usage.
154 * Invoking guix graph:: Visualizing the graph of packages.
155 * Invoking guix environment:: Setting up development environments.
156 * Invoking guix publish:: Sharing substitutes.
157 * Invoking guix challenge:: Challenging substitute servers.
158 * Invoking guix copy:: Copying to and from a remote store.
159 * Invoking guix container:: Process isolation.
161 Invoking @command{guix build}
163 * Common Build Options:: Build options for most commands.
164 * Package Transformation Options:: Creating variants of packages.
165 * Additional Build Options:: Options specific to 'guix build'.
169 * System Installation:: Installing the whole operating system.
170 * System Configuration:: Configuring the operating system.
171 * Documentation:: Browsing software user manuals.
172 * Installing Debugging Files:: Feeding the debugger.
173 * Security Updates:: Deploying security fixes quickly.
174 * Package Modules:: Packages from the programmer's viewpoint.
175 * Packaging Guidelines:: Growing the distribution.
176 * Bootstrapping:: GNU/Linux built from scratch.
177 * Porting:: Targeting another platform or kernel.
181 * Limitations:: What you can expect.
182 * Hardware Considerations:: Supported hardware.
183 * USB Stick Installation:: Preparing the installation medium.
184 * Preparing for Installation:: Networking, partitioning, etc.
185 * Proceeding with the Installation:: The real thing.
186 * Installing GuixSD in a VM:: GuixSD playground.
187 * Building the Installation Image:: How this comes to be.
191 * Using the Configuration System:: Customizing your GNU system.
192 * operating-system Reference:: Detail of operating-system declarations.
193 * File Systems:: Configuring file system mounts.
194 * Mapped Devices:: Block device extra processing.
195 * User Accounts:: Specifying user accounts.
196 * Locales:: Language and cultural convention settings.
197 * Services:: Specifying system services.
198 * Setuid Programs:: Programs running with root privileges.
199 * X.509 Certificates:: Authenticating HTTPS servers.
200 * Name Service Switch:: Configuring libc's name service switch.
201 * Initial RAM Disk:: Linux-Libre bootstrapping.
202 * Bootloader Configuration:: Configuring the boot loader.
203 * Invoking guix system:: Instantiating a system configuration.
204 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
205 * Defining Services:: Adding new service definitions.
209 * Base Services:: Essential system services.
210 * Scheduled Job Execution:: The mcron service.
211 * Log Rotation:: The rottlog service.
212 * Networking Services:: Network setup, SSH daemon, etc.
213 * X Window:: Graphical display.
214 * Printing Services:: Local and remote printer support.
215 * Desktop Services:: D-Bus and desktop services.
216 * Database Services:: SQL databases.
217 * Mail Services:: IMAP, POP3, SMTP, and all that.
218 * Messaging Services:: Messaging services.
219 * Kerberos Services:: Kerberos services.
220 * Web Services:: Web servers.
221 * DNS Services:: DNS daemons.
222 * VPN Services:: VPN daemons.
223 * Network File System:: NFS related services.
224 * Continuous Integration:: The Cuirass service.
225 * Power management Services:: The TLP tool.
226 * Miscellaneous Services:: Other services.
230 * Service Composition:: The model for composing services.
231 * Service Types and Services:: Types and services.
232 * Service Reference:: API reference.
233 * Shepherd Services:: A particular type of service.
237 * Software Freedom:: What may go into the distribution.
238 * Package Naming:: What's in a name?
239 * Version Numbers:: When the name is not enough.
240 * Synopses and Descriptions:: Helping users find the right package.
241 * Python Modules:: A touch of British comedy.
242 * Perl Modules:: Little pearls.
243 * Java Packages:: Coffee break.
244 * Fonts:: Fond of fonts.
248 * Building from Git:: The latest and greatest.
249 * Running Guix Before It Is Installed:: Hacker tricks.
250 * The Perfect Setup:: The right tools.
251 * Coding Style:: Hygiene of the contributor.
252 * Submitting Patches:: Share your work.
256 * Programming Paradigm:: How to compose your elements.
257 * Modules:: Where to store your code?
258 * Data Types and Pattern Matching:: Implementing data structures.
259 * Formatting Code:: Writing conventions.
264 @c *********************************************************************
266 @chapter Introduction
269 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
270 using the international phonetic alphabet (IPA).} is a package
271 management tool for the GNU system. Guix makes it easy for unprivileged
272 users to install, upgrade, or remove packages, to roll back to a
273 previous package set, to build packages from source, and generally
274 assists with the creation and maintenance of software environments.
276 @cindex user interfaces
277 Guix provides a command-line package management interface
278 (@pxref{Invoking guix package}), a set of command-line utilities
279 (@pxref{Utilities}), as well as Scheme programming interfaces
280 (@pxref{Programming Interface}).
282 Its @dfn{build daemon} is responsible for building packages on behalf of
283 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
284 binaries from authorized sources (@pxref{Substitutes}).
286 @cindex extensibility of the distribution
287 @cindex customization, of packages
288 Guix includes package definitions for many GNU and non-GNU packages, all
289 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
290 user's computing freedom}. It is @emph{extensible}: users can write
291 their own package definitions (@pxref{Defining Packages}) and make them
292 available as independent package modules (@pxref{Package Modules}). It
293 is also @emph{customizable}: users can @emph{derive} specialized package
294 definitions from existing ones, including from the command line
295 (@pxref{Package Transformation Options}).
297 @cindex Guix System Distribution
299 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
300 where it complements the available tools without interference
301 (@pxref{Installation}), or you can use it as part of the standalone
302 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
303 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
304 system configuration and Guix takes care of instantiating the
305 configuration in a transactional, reproducible, and stateless fashion
306 (@pxref{System Configuration}).
308 @cindex functional package management
309 Under the hood, Guix implements the @dfn{functional package management}
310 discipline pioneered by Nix (@pxref{Acknowledgments}).
311 In Guix, the package build and installation process is seen
312 as a @emph{function}, in the mathematical sense. That function takes inputs,
313 such as build scripts, a compiler, and libraries, and
314 returns an installed package. As a pure function, its result depends
315 solely on its inputs---for instance, it cannot refer to software or
316 scripts that were not explicitly passed as inputs. A build function
317 always produces the same result when passed a given set of inputs. It
318 cannot alter the environment of the running system in
319 any way; for instance, it cannot create, modify, or delete files outside
320 of its build and installation directories. This is achieved by running
321 build processes in isolated environments (or @dfn{containers}), where only their
322 explicit inputs are visible.
325 The result of package build functions is @dfn{cached} in the file
326 system, in a special directory called @dfn{the store} (@pxref{The
327 Store}). Each package is installed in a directory of its own in the
328 store---by default under @file{/gnu/store}. The directory name contains
329 a hash of all the inputs used to build that package; thus, changing an
330 input yields a different directory name.
332 This approach is the foundation for the salient features of Guix: support
333 for transactional package upgrade and rollback, per-user installation, and
334 garbage collection of packages (@pxref{Features}).
337 @c *********************************************************************
339 @chapter Installation
341 @cindex installing Guix
342 GNU Guix is available for download from its website at
343 @url{http://www.gnu.org/software/guix/}. This section describes the
344 software requirements of Guix, as well as how to install it and get
347 Note that this section is concerned with the installation of the package
348 manager, which can be done on top of a running GNU/Linux system. If,
349 instead, you want to install the complete GNU operating system,
350 @pxref{System Installation}.
352 @cindex foreign distro
353 When installed on a running GNU/Linux system---thereafter called a
354 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
355 without interference. Its data lives exclusively in two directories,
356 usually @file{/gnu/store} and @file{/var/guix}; other files on your
357 system, such as @file{/etc}, are left untouched.
359 Once installed, Guix can be updated by running @command{guix pull}
360 (@pxref{Invoking guix pull}).
363 * Binary Installation:: Getting Guix running in no time!
364 * Requirements:: Software needed to build and run Guix.
365 * Running the Test Suite:: Testing Guix.
366 * Setting Up the Daemon:: Preparing the build daemon's environment.
367 * Invoking guix-daemon:: Running the build daemon.
368 * Application Setup:: Application-specific setup.
371 @node Binary Installation
372 @section Binary Installation
374 @cindex installing Guix from binaries
375 This section describes how to install Guix on an arbitrary system from a
376 self-contained tarball providing binaries for Guix and for all its
377 dependencies. This is often quicker than installing from source, which
378 is described in the next sections. The only requirement is to have
381 Installing goes along these lines:
385 @cindex downloading Guix binary
386 Download the binary tarball from
387 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
388 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
389 already running the kernel Linux, and so on.
391 @c The following is somewhat duplicated in ``System Installation''.
392 Make sure to download the associated @file{.sig} file and to verify the
393 authenticity of the tarball against it, along these lines:
396 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
397 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
400 If that command fails because you do not have the required public key,
401 then run this command to import it:
404 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
408 and rerun the @code{gpg --verify} command.
409 @c end authentication part
416 # tar --warning=no-timestamp -xf \
417 guix-binary-@value{VERSION}.@var{system}.tar.xz
418 # mv var/guix /var/ && mv gnu /
421 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
422 The latter contains a ready-to-use profile for @code{root} (see next
425 Do @emph{not} unpack the tarball on a working Guix system since that
426 would overwrite its own essential files.
428 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
429 not emit warnings about ``implausibly old time stamps'' (such
430 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
432 They stem from the fact that all the
433 files in the archive have their modification time set to zero (which
434 means January 1st, 1970.) This is done on purpose to make sure the
435 archive content is independent of its creation time, thus making it
439 Make @code{root}'s profile available under @file{~/.guix-profile}:
442 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
446 Source @file{etc/profile} to augment @code{PATH} and other relevant
447 environment variables:
450 # GUIX_PROFILE=$HOME/.guix-profile \
451 source $GUIX_PROFILE/etc/profile
455 Create the group and user accounts for build users as explained below
456 (@pxref{Build Environment Setup}).
459 Run the daemon, and set it to automatically start on boot.
461 If your host distro uses the systemd init system, this can be achieved
464 @c Versions of systemd that supported symlinked service files are not
465 @c yet widely deployed, so we should suggest that users copy the service
468 @c See this thread for more information:
469 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
472 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
474 # systemctl start guix-daemon && systemctl enable guix-daemon
477 If your host distro uses the Upstart init system:
480 # initctl reload-configuration
481 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
485 Otherwise, you can still start the daemon manually with:
488 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
492 Make the @command{guix} command available to other users on the machine,
496 # mkdir -p /usr/local/bin
498 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
501 It is also a good idea to make the Info version of this manual available
505 # mkdir -p /usr/local/share/info
506 # cd /usr/local/share/info
507 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
511 That way, assuming @file{/usr/local/share/info} is in the search path,
512 running @command{info guix} will open this manual (@pxref{Other Info
513 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
517 @cindex substitutes, authorization thereof
518 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
519 (@pxref{Substitutes}), authorize them:
522 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
526 Each user may need to perform a few additional steps to make their Guix
527 environment ready for use, @pxref{Application Setup}.
530 Voilà, the installation is complete!
532 You can confirm that Guix is working by installing a sample package into
536 # guix package -i hello
539 The @code{guix} package must remain available in @code{root}'s profile,
540 or it would become subject to garbage collection---in which case you
541 would find yourself badly handicapped by the lack of the @command{guix}
542 command. In other words, do not remove @code{guix} by running
543 @code{guix package -r guix}.
545 The binary installation tarball can be (re)produced and verified simply
546 by running the following command in the Guix source tree:
549 make guix-binary.@var{system}.tar.xz
553 ... which, in turn, runs:
556 guix pack -s @var{system} --localstatedir guix
559 @xref{Invoking guix pack}, for more info on this handy tool.
562 @section Requirements
564 This section lists requirements when building Guix from source. The
565 build procedure for Guix is the same as for other GNU software, and is
566 not covered here. Please see the files @file{README} and @file{INSTALL}
567 in the Guix source tree for additional details.
569 GNU Guix depends on the following packages:
572 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
573 later, including 2.2.x;
574 @item @url{http://gnupg.org/, GNU libgcrypt};
576 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
577 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
578 Guile,, gnutls-guile, GnuTLS-Guile});
579 @item @url{http://www.gnu.org/software/make/, GNU Make}.
582 The following dependencies are optional:
587 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
588 allow you to use the @command{guix import pypi} command (@pxref{Invoking
589 guix import}). It is of
590 interest primarily for developers and not for casual users.
593 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
594 Support for build offloading (@pxref{Daemon Offload Setup}) and
595 @command{guix copy} (@pxref{Invoking guix copy}) depends on
596 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
597 version 0.10.2 or later.
600 When @url{http://zlib.net, zlib} is available, @command{guix publish}
601 can compress build byproducts (@pxref{Invoking guix publish}).
604 Unless @code{--disable-daemon} was passed to @command{configure}, the
605 following packages are also needed:
608 @item @url{http://sqlite.org, SQLite 3};
609 @item @url{http://www.bzip.org, libbz2};
610 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
614 @cindex state directory
615 When configuring Guix on a system that already has a Guix installation,
616 be sure to specify the same state directory as the existing installation
617 using the @code{--localstatedir} option of the @command{configure}
618 script (@pxref{Directory Variables, @code{localstatedir},, standards,
619 GNU Coding Standards}). The @command{configure} script protects against
620 unintended misconfiguration of @var{localstatedir} so you do not
621 inadvertently corrupt your store (@pxref{The Store}).
623 @cindex Nix, compatibility
624 When a working installation of @url{http://nixos.org/nix/, the Nix package
625 manager} is available, you
626 can instead configure Guix with @code{--disable-daemon}. In that case,
627 Nix replaces the three dependencies above.
629 Guix is compatible with Nix, so it is possible to share the same store
630 between both. To do so, you must pass @command{configure} not only the
631 same @code{--with-store-dir} value, but also the same
632 @code{--localstatedir} value. The latter is essential because it
633 specifies where the database that stores metadata about the store is
634 located, among other things. The default values for Nix are
635 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
636 Note that @code{--disable-daemon} is not required if
637 your goal is to share the store with Nix.
639 @node Running the Test Suite
640 @section Running the Test Suite
643 After a successful @command{configure} and @code{make} run, it is a good
644 idea to run the test suite. It can help catch issues with the setup or
645 environment, or bugs in Guix itself---and really, reporting test
646 failures is a good way to help improve the software. To run the test
653 Test cases can run in parallel: you can use the @code{-j} option of
654 GNU@tie{}make to speed things up. The first run may take a few minutes
655 on a recent machine; subsequent runs will be faster because the store
656 that is created for test purposes will already have various things in
659 It is also possible to run a subset of the tests by defining the
660 @code{TESTS} makefile variable as in this example:
663 make check TESTS="tests/store.scm tests/cpio.scm"
666 By default, tests results are displayed at a file level. In order to
667 see the details of every individual test cases, it is possible to define
668 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
671 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
674 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
675 @file{test-suite.log} file. Please specify the Guix version being used
676 as well as version numbers of the dependencies (@pxref{Requirements}) in
679 Guix also comes with a whole-system test suite that tests complete
680 GuixSD operating system instances. It can only run on systems where
681 Guix is already installed, using:
688 or, again, by defining @code{TESTS} to select a subset of tests to run:
691 make check-system TESTS="basic mcron"
694 These system tests are defined in the @code{(gnu tests @dots{})}
695 modules. They work by running the operating systems under test with
696 lightweight instrumentation in a virtual machine (VM). They can be
697 computationally intensive or rather cheap, depending on whether
698 substitutes are available for their dependencies (@pxref{Substitutes}).
699 Some of them require a lot of storage space to hold VM images.
701 Again in case of test failures, please send @email{bug-guix@@gnu.org}
704 @node Setting Up the Daemon
705 @section Setting Up the Daemon
708 Operations such as building a package or running the garbage collector
709 are all performed by a specialized process, the @dfn{build daemon}, on
710 behalf of clients. Only the daemon may access the store and its
711 associated database. Thus, any operation that manipulates the store
712 goes through the daemon. For instance, command-line tools such as
713 @command{guix package} and @command{guix build} communicate with the
714 daemon (@i{via} remote procedure calls) to instruct it what to do.
716 The following sections explain how to prepare the build daemon's
717 environment. See also @ref{Substitutes}, for information on how to allow
718 the daemon to download pre-built binaries.
721 * Build Environment Setup:: Preparing the isolated build environment.
722 * Daemon Offload Setup:: Offloading builds to remote machines.
725 @node Build Environment Setup
726 @subsection Build Environment Setup
728 @cindex build environment
729 In a standard multi-user setup, Guix and its daemon---the
730 @command{guix-daemon} program---are installed by the system
731 administrator; @file{/gnu/store} is owned by @code{root} and
732 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
733 Guix tools to build packages or otherwise access the store, and the
734 daemon will do it on their behalf, ensuring that the store is kept in a
735 consistent state, and allowing built packages to be shared among users.
738 When @command{guix-daemon} runs as @code{root}, you may not want package
739 build processes themselves to run as @code{root} too, for obvious
740 security reasons. To avoid that, a special pool of @dfn{build users}
741 should be created for use by build processes started by the daemon.
742 These build users need not have a shell and a home directory: they will
743 just be used when the daemon drops @code{root} privileges in build
744 processes. Having several such users allows the daemon to launch
745 distinct build processes under separate UIDs, which guarantees that they
746 do not interfere with each other---an essential feature since builds are
747 regarded as pure functions (@pxref{Introduction}).
749 On a GNU/Linux system, a build user pool may be created like this (using
750 Bash syntax and the @code{shadow} commands):
752 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
753 @c for why `-G' is needed.
755 # groupadd --system guixbuild
756 # for i in `seq -w 1 10`;
758 useradd -g guixbuild -G guixbuild \
759 -d /var/empty -s `which nologin` \
760 -c "Guix build user $i" --system \
766 The number of build users determines how many build jobs may run in
767 parallel, as specified by the @option{--max-jobs} option
768 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
769 @command{guix system vm} and related commands, you may need to add the
770 build users to the @code{kvm} group so they can access @file{/dev/kvm},
771 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
772 (@pxref{Invoking guix system}).
774 The @code{guix-daemon} program may then be run as @code{root} with the
775 following command@footnote{If your machine uses the systemd init system,
776 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
777 file in @file{/etc/systemd/system} will ensure that
778 @command{guix-daemon} is automatically started. Similarly, if your
779 machine uses the Upstart init system, drop the
780 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
781 file in @file{/etc/init}.}:
784 # guix-daemon --build-users-group=guixbuild
789 This way, the daemon starts build processes in a chroot, under one of
790 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
791 environment contains nothing but:
793 @c Keep this list in sync with libstore/build.cc! -----------------------
796 a minimal @code{/dev} directory, created mostly independently from the
797 host @code{/dev}@footnote{``Mostly'', because while the set of files
798 that appear in the chroot's @code{/dev} is fixed, most of these files
799 can only be created if the host has them.};
802 the @code{/proc} directory; it only shows the processes of the container
803 since a separate PID name space is used;
806 @file{/etc/passwd} with an entry for the current user and an entry for
810 @file{/etc/group} with an entry for the user's group;
813 @file{/etc/hosts} with an entry that maps @code{localhost} to
817 a writable @file{/tmp} directory.
820 You can influence the directory where the daemon stores build trees
821 @i{via} the @code{TMPDIR} environment variable. However, the build tree
822 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
823 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
824 This way, the value of @code{TMPDIR} does not leak inside build
825 environments, which avoids discrepancies in cases where build processes
826 capture the name of their build tree.
829 The daemon also honors the @code{http_proxy} environment variable for
830 HTTP downloads it performs, be it for fixed-output derivations
831 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
833 If you are installing Guix as an unprivileged user, it is still possible
834 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
835 However, build processes will not be isolated from one another, and not
836 from the rest of the system. Thus, build processes may interfere with
837 each other, and may access programs, libraries, and other files
838 available on the system---making it much harder to view them as
839 @emph{pure} functions.
842 @node Daemon Offload Setup
843 @subsection Using the Offload Facility
847 When desired, the build daemon can @dfn{offload} derivation builds to
848 other machines running Guix, using the @code{offload} @dfn{build
849 hook}@footnote{This feature is available only when
850 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
852 feature is enabled, a list of user-specified build machines is read from
853 @file{/etc/guix/machines.scm}; every time a build is requested, for
854 instance via @code{guix build}, the daemon attempts to offload it to one
855 of the machines that satisfy the constraints of the derivation, in
856 particular its system type---e.g., @file{x86_64-linux}. Missing
857 prerequisites for the build are copied over SSH to the target machine,
858 which then proceeds with the build; upon success the output(s) of the
859 build are copied back to the initial machine.
861 The @file{/etc/guix/machines.scm} file typically looks like this:
865 (name "eightysix.example.org")
866 (system "x86_64-linux")
867 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
869 (speed 2.)) ;incredibly fast!
872 (name "meeps.example.org")
873 (system "mips64el-linux")
874 (host-key "ssh-rsa AAAAB3Nza@dots{}")
877 (string-append (getenv "HOME")
878 "/.ssh/identity-for-guix"))))
882 In the example above we specify a list of two build machines, one for
883 the @code{x86_64} architecture and one for the @code{mips64el}
886 In fact, this file is---not surprisingly!---a Scheme file that is
887 evaluated when the @code{offload} hook is started. Its return value
888 must be a list of @code{build-machine} objects. While this example
889 shows a fixed list of build machines, one could imagine, say, using
890 DNS-SD to return a list of potential build machines discovered in the
891 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
892 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
895 @deftp {Data Type} build-machine
896 This data type represents build machines to which the daemon may offload
897 builds. The important fields are:
902 The host name of the remote machine.
905 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
908 The user account to use when connecting to the remote machine over SSH.
909 Note that the SSH key pair must @emph{not} be passphrase-protected, to
910 allow non-interactive logins.
913 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
914 This is used to authenticate the machine when we connect to it. It is a
915 long string that looks like this:
918 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
921 If the machine is running the OpenSSH daemon, @command{sshd}, the host
922 key can be found in a file such as
923 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
925 If the machine is running the SSH daemon of GNU@tie{}lsh,
926 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
927 similar file. It can be converted to the OpenSSH format using
928 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
931 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
932 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
937 A number of optional fields may be specified:
941 @item @code{port} (default: @code{22})
942 Port number of SSH server on the machine.
944 @item @code{private-key} (default: @file{~/.ssh/id_rsa})
945 The SSH private key file to use when connecting to the machine, in
948 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
949 @itemx @code{compression-level} (default: @code{3})
950 The SSH-level compression methods and compression level requested.
952 Note that offloading relies on SSH compression to reduce bandwidth usage
953 when transferring files to and from build machines.
955 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
956 File name of the Unix-domain socket @command{guix-daemon} is listening
959 @item @code{parallel-builds} (default: @code{1})
960 The number of builds that may run in parallel on the machine.
962 @item @code{speed} (default: @code{1.0})
963 A ``relative speed factor''. The offload scheduler will tend to prefer
964 machines with a higher speed factor.
966 @item @code{features} (default: @code{'()})
967 A list of strings denoting specific features supported by the machine.
968 An example is @code{"kvm"} for machines that have the KVM Linux modules
969 and corresponding hardware support. Derivations can request features by
970 name, and they will be scheduled on matching build machines.
975 The @code{guile} command must be in the search path on the build
976 machines. In addition, the Guix modules must be in
977 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
978 this is the case by running:
981 ssh build-machine guile -c "'(use-modules (guix config))'"
984 There is one last thing to do once @file{machines.scm} is in place. As
985 explained above, when offloading, files are transferred back and forth
986 between the machine stores. For this to work, you first need to
987 generate a key pair on each machine to allow the daemon to export signed
988 archives of files from the store (@pxref{Invoking guix archive}):
991 # guix archive --generate-key
995 Each build machine must authorize the key of the master machine so that
996 it accepts store items it receives from the master:
999 # guix archive --authorize < master-public-key.txt
1003 Likewise, the master machine must authorize the key of each build machine.
1005 All the fuss with keys is here to express pairwise mutual trust
1006 relations between the master and the build machines. Concretely, when
1007 the master receives files from a build machine (and @i{vice versa}), its
1008 build daemon can make sure they are genuine, have not been tampered
1009 with, and that they are signed by an authorized key.
1011 @cindex offload test
1012 To test whether your setup is operational, run this command on the
1019 This will attempt to connect to each of the build machines specified in
1020 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1021 available on each machine, attempt to export to the machine and import
1022 from it, and report any error in the process.
1024 If you want to test a different machine file, just specify it on the
1028 # guix offload test machines-qualif.scm
1031 Last, you can test the subset of the machines whose name matches a
1032 regular expression like this:
1035 # guix offload test machines.scm '\.gnu\.org$'
1038 @node Invoking guix-daemon
1039 @section Invoking @command{guix-daemon}
1041 The @command{guix-daemon} program implements all the functionality to
1042 access the store. This includes launching build processes, running the
1043 garbage collector, querying the availability of a build result, etc. It
1044 is normally run as @code{root} like this:
1047 # guix-daemon --build-users-group=guixbuild
1051 For details on how to set it up, @pxref{Setting Up the Daemon}.
1054 @cindex container, build environment
1055 @cindex build environment
1056 @cindex reproducible builds
1057 By default, @command{guix-daemon} launches build processes under
1058 different UIDs, taken from the build group specified with
1059 @code{--build-users-group}. In addition, each build process is run in a
1060 chroot environment that only contains the subset of the store that the
1061 build process depends on, as specified by its derivation
1062 (@pxref{Programming Interface, derivation}), plus a set of specific
1063 system directories. By default, the latter contains @file{/dev} and
1064 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1065 @dfn{container}: in addition to having its own file system tree, it has
1066 a separate mount name space, its own PID name space, network name space,
1067 etc. This helps achieve reproducible builds (@pxref{Features}).
1069 When the daemon performs a build on behalf of the user, it creates a
1070 build directory under @file{/tmp} or under the directory specified by
1071 its @code{TMPDIR} environment variable; this directory is shared with
1072 the container for the duration of the build. Be aware that using a
1073 directory other than @file{/tmp} can affect build results---for example,
1074 with a longer directory name, a build process that uses Unix-domain
1075 sockets might hit the name length limitation for @code{sun_path}, which
1076 it would otherwise not hit.
1078 The build directory is automatically deleted upon completion, unless the
1079 build failed and the client specified @option{--keep-failed}
1080 (@pxref{Invoking guix build, @option{--keep-failed}}).
1082 The following command-line options are supported:
1085 @item --build-users-group=@var{group}
1086 Take users from @var{group} to run build processes (@pxref{Setting Up
1087 the Daemon, build users}).
1089 @item --no-substitutes
1091 Do not use substitutes for build products. That is, always build things
1092 locally instead of allowing downloads of pre-built binaries
1093 (@pxref{Substitutes}).
1095 By default substitutes are used, unless the client---such as the
1096 @command{guix package} command---is explicitly invoked with
1097 @code{--no-substitutes}.
1099 When the daemon runs with @code{--no-substitutes}, clients can still
1100 explicitly enable substitution @i{via} the @code{set-build-options}
1101 remote procedure call (@pxref{The Store}).
1103 @item --substitute-urls=@var{urls}
1104 @anchor{daemon-substitute-urls}
1105 Consider @var{urls} the default whitespace-separated list of substitute
1106 source URLs. When this option is omitted,
1107 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1108 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1110 This means that substitutes may be downloaded from @var{urls}, as long
1111 as they are signed by a trusted signature (@pxref{Substitutes}).
1114 @item --no-build-hook
1115 Do not use the @dfn{build hook}.
1117 The build hook is a helper program that the daemon can start and to
1118 which it submits build requests. This mechanism is used to offload
1119 builds to other machines (@pxref{Daemon Offload Setup}).
1121 @item --cache-failures
1122 Cache build failures. By default, only successful builds are cached.
1124 When this option is used, @command{guix gc --list-failures} can be used
1125 to query the set of store items marked as failed; @command{guix gc
1126 --clear-failures} removes store items from the set of cached failures.
1127 @xref{Invoking guix gc}.
1129 @item --cores=@var{n}
1131 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1134 The default value is @code{0}, but it may be overridden by clients, such
1135 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1138 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1139 in the build process, which can then use it to exploit internal
1140 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1142 @item --max-jobs=@var{n}
1144 Allow at most @var{n} build jobs in parallel. The default value is
1145 @code{1}. Setting it to @code{0} means that no builds will be performed
1146 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1147 Setup}), or simply fail.
1149 @item --max-silent-time=@var{seconds}
1150 When the build or substitution process remains silent for more than
1151 @var{seconds}, terminate it and report a build failure.
1153 The default value is @code{0}, which disables the timeout.
1155 The value specified here can be overridden by clients (@pxref{Common
1156 Build Options, @code{--max-silent-time}}).
1158 @item --timeout=@var{seconds}
1159 Likewise, when the build or substitution process lasts for more than
1160 @var{seconds}, terminate it and report a build failure.
1162 The default value is @code{0}, which disables the timeout.
1164 The value specified here can be overridden by clients (@pxref{Common
1165 Build Options, @code{--timeout}}).
1167 @item --rounds=@var{N}
1168 Build each derivation @var{n} times in a row, and raise an error if
1169 consecutive build results are not bit-for-bit identical. Note that this
1170 setting can be overridden by clients such as @command{guix build}
1171 (@pxref{Invoking guix build}).
1173 When used in conjunction with @option{--keep-failed}, the differing
1174 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1175 This makes it easy to look for differences between the two results.
1178 Produce debugging output.
1180 This is useful to debug daemon start-up issues, but then it may be
1181 overridden by clients, for example the @code{--verbosity} option of
1182 @command{guix build} (@pxref{Invoking guix build}).
1184 @item --chroot-directory=@var{dir}
1185 Add @var{dir} to the build chroot.
1187 Doing this may change the result of build processes---for instance if
1188 they use optional dependencies found in @var{dir} when it is available,
1189 and not otherwise. For that reason, it is not recommended to do so.
1190 Instead, make sure that each derivation declares all the inputs that it
1193 @item --disable-chroot
1194 Disable chroot builds.
1196 Using this option is not recommended since, again, it would allow build
1197 processes to gain access to undeclared dependencies. It is necessary,
1198 though, when @command{guix-daemon} is running under an unprivileged user
1201 @item --disable-log-compression
1202 Disable compression of the build logs.
1204 Unless @code{--lose-logs} is used, all the build logs are kept in the
1205 @var{localstatedir}. To save space, the daemon automatically compresses
1206 them with bzip2 by default. This option disables that.
1208 @item --disable-deduplication
1209 @cindex deduplication
1210 Disable automatic file ``deduplication'' in the store.
1212 By default, files added to the store are automatically ``deduplicated'':
1213 if a newly added file is identical to another one found in the store,
1214 the daemon makes the new file a hard link to the other file. This can
1215 noticeably reduce disk usage, at the expense of slightly increased
1216 input/output load at the end of a build process. This option disables
1219 @item --gc-keep-outputs[=yes|no]
1220 Tell whether the garbage collector (GC) must keep outputs of live
1223 When set to ``yes'', the GC will keep the outputs of any live derivation
1224 available in the store---the @code{.drv} files. The default is ``no'',
1225 meaning that derivation outputs are kept only if they are GC roots.
1227 @item --gc-keep-derivations[=yes|no]
1228 Tell whether the garbage collector (GC) must keep derivations
1229 corresponding to live outputs.
1231 When set to ``yes'', as is the case by default, the GC keeps
1232 derivations---i.e., @code{.drv} files---as long as at least one of their
1233 outputs is live. This allows users to keep track of the origins of
1234 items in their store. Setting it to ``no'' saves a bit of disk space.
1236 Note that when both @code{--gc-keep-derivations} and
1237 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1238 prerequisites (the sources, compiler, libraries, and other build-time
1239 tools) of live objects in the store, regardless of whether these
1240 prerequisites are live. This is convenient for developers since it
1241 saves rebuilds or downloads.
1243 @item --impersonate-linux-2.6
1244 On Linux-based systems, impersonate Linux 2.6. This means that the
1245 kernel's @code{uname} system call will report 2.6 as the release number.
1247 This might be helpful to build programs that (usually wrongfully) depend
1248 on the kernel version number.
1251 Do not keep build logs. By default they are kept under
1252 @code{@var{localstatedir}/guix/log}.
1254 @item --system=@var{system}
1255 Assume @var{system} as the current system type. By default it is the
1256 architecture/kernel pair found at configure time, such as
1257 @code{x86_64-linux}.
1259 @item --listen=@var{socket}
1260 Listen for connections on @var{socket}, the file name of a Unix-domain
1261 socket. The default socket is
1262 @file{@var{localstatedir}/daemon-socket/socket}. This option is only
1263 useful in exceptional circumstances, such as if you need to run several
1264 daemons on the same machine.
1268 @node Application Setup
1269 @section Application Setup
1271 @cindex foreign distro
1272 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1273 so-called @dfn{foreign distro}---a few additional steps are needed to
1274 get everything in place. Here are some of them.
1278 @anchor{locales-and-locpath}
1279 @cindex locales, when not on GuixSD
1281 @vindex GUIX_LOCPATH
1282 Packages installed @i{via} Guix will not use the locale data of the
1283 host system. Instead, you must first install one of the locale packages
1284 available with Guix and then define the @code{GUIX_LOCPATH} environment
1288 $ guix package -i glibc-locales
1289 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1292 Note that the @code{glibc-locales} package contains data for all the
1293 locales supported by the GNU@tie{}libc and weighs in at around
1294 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1295 limited to a few UTF-8 locales.
1297 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1298 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1299 Manual}). There are two important differences though:
1303 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1304 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1305 to make sure the programs of the foreign distro will not end up loading
1306 incompatible locale data.
1309 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1310 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1311 should your Guix profile contain a mixture of programs linked against
1312 different libc version, each libc version will only try to load locale
1313 data in the right format.
1316 This is important because the locale data format used by different libc
1317 versions may be incompatible.
1319 @subsection Name Service Switch
1321 @cindex name service switch, glibc
1322 @cindex NSS (name service switch), glibc
1323 @cindex nscd (name service caching daemon)
1324 @cindex name service caching daemon (nscd)
1325 When using Guix on a foreign distro, we @emph{strongly recommend} that
1326 the system run the GNU C library's @dfn{name service cache daemon},
1327 @command{nscd}, which should be listening on the
1328 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1329 installed with Guix may fail to look up host names or user accounts, or
1330 may even crash. The next paragraphs explain why.
1332 @cindex @file{nsswitch.conf}
1333 The GNU C library implements a @dfn{name service switch} (NSS), which is
1334 an extensible mechanism for ``name lookups'' in general: host name
1335 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1336 The GNU C Library Reference Manual}).
1338 @cindex Network information service (NIS)
1339 @cindex NIS (Network information service)
1340 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1341 lookup implementations: for example, the @code{nss-mdns} plugin allow
1342 resolution of @code{.local} host names, the @code{nis} plugin allows
1343 user account lookup using the Network information service (NIS), and so
1344 on. These extra ``lookup services'' are configured system-wide in
1345 @file{/etc/nsswitch.conf}, and all the programs running on the system
1346 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1349 When they perform a name lookup---for instance by calling the
1350 @code{getaddrinfo} function in C---applications first try to connect to
1351 the nscd; on success, nscd performs name lookups on their behalf. If
1352 the nscd is not running, then they perform the name lookup by
1353 themselves, by loading the name lookup services into their own address
1354 space and running it. These name lookup services---the
1355 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1356 the host system's C library, rather than from the C library the
1357 application is linked against (the C library coming from Guix).
1359 And this is where the problem is: if your application is linked against
1360 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1361 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1362 likely crash or have its name lookups fail unexpectedly.
1364 Running @command{nscd} on the system, among other advantages, eliminates
1365 this binary incompatibility problem because those @code{libnss_*.so}
1366 files are loaded in the @command{nscd} process, not in applications
1369 @subsection X11 Fonts
1372 The majority of graphical applications use Fontconfig to locate and
1373 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1374 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1375 by default. Thus, to allow graphical applications installed with Guix
1376 to display fonts, you have to install fonts with Guix as well.
1377 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1378 @code{font-gnu-freefont-ttf}.
1380 To display text written in Chinese languages, Japanese, or Korean in
1381 graphical applications, consider installing
1382 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1383 has multiple outputs, one per language family (@pxref{Packages with
1384 Multiple Outputs}). For instance, the following command installs fonts
1385 for Chinese languages:
1388 guix package -i font-adobe-source-han-sans:cn
1391 @cindex @code{xterm}
1392 Older programs such as @command{xterm} do not use Fontconfig and instead
1393 rely on server-side font rendering. Such programs require to specify a
1394 full name of a font using XLFD (X Logical Font Description), like this:
1397 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1400 To be able to use such full names for the TrueType fonts installed in
1401 your Guix profile, you need to extend the font path of the X server:
1404 xset +fp ~/.guix-profile/share/fonts/truetype
1407 @cindex @code{xlsfonts}
1408 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1409 to make sure your TrueType fonts are listed there.
1411 @subsection X.509 Certificates
1413 @cindex @code{nss-certs}
1414 The @code{nss-certs} package provides X.509 certificates, which allow
1415 programs to authenticate Web servers accessed over HTTPS.
1417 When using Guix on a foreign distro, you can install this package and
1418 define the relevant environment variables so that packages know where to
1419 look for certificates. @xref{X.509 Certificates}, for detailed
1422 @subsection Emacs Packages
1424 @cindex @code{emacs}
1425 When you install Emacs packages with Guix, the elisp files may be placed
1426 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1428 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1429 directory exists because potentially there may exist thousands of Emacs
1430 packages and storing all their files in a single directory may be not
1431 reliable (because of name conflicts). So we think using a separate
1432 directory for each package is a good idea. It is very similar to how
1433 the Emacs package system organizes the file structure (@pxref{Package
1434 Files,,, emacs, The GNU Emacs Manual}).
1436 By default, Emacs (installed with Guix) ``knows'' where these packages
1437 are placed, so you do not need to perform any configuration. If, for
1438 some reason, you want to avoid auto-loading Emacs packages installed
1439 with Guix, you can do so by running Emacs with @code{--no-site-file}
1440 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1444 @c *********************************************************************
1445 @node Package Management
1446 @chapter Package Management
1449 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1450 remove software packages, without having to know about their build
1451 procedures or dependencies. Guix also goes beyond this obvious set of
1454 This chapter describes the main features of Guix, as well as the
1455 package management tools it provides. Along with the command-line
1456 interface described below (@pxref{Invoking guix package, @code{guix
1457 package}}), you may also use Emacs Interface (@pxref{Top,,,
1458 emacs-guix, The Emacs-Guix Reference Manual}), after installing
1459 @code{emacs-guix} package (run @kbd{M-x guix-help} command to start
1463 guix package -i emacs-guix
1467 * Features:: How Guix will make your life brighter.
1468 * Invoking guix package:: Package installation, removal, etc.
1469 * Substitutes:: Downloading pre-built binaries.
1470 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1471 * Invoking guix gc:: Running the garbage collector.
1472 * Invoking guix pull:: Fetching the latest Guix and distribution.
1473 * Invoking guix pack:: Creating software bundles.
1474 * Invoking guix archive:: Exporting and importing store files.
1480 When using Guix, each package ends up in the @dfn{package store}, in its
1481 own directory---something that resembles
1482 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1484 Instead of referring to these directories, users have their own
1485 @dfn{profile}, which points to the packages that they actually want to
1486 use. These profiles are stored within each user's home directory, at
1487 @code{$HOME/.guix-profile}.
1489 For example, @code{alice} installs GCC 4.7.2. As a result,
1490 @file{/home/alice/.guix-profile/bin/gcc} points to
1491 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1492 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1493 simply continues to point to
1494 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1495 coexist on the same system without any interference.
1497 The @command{guix package} command is the central tool to manage
1498 packages (@pxref{Invoking guix package}). It operates on the per-user
1499 profiles, and can be used @emph{with normal user privileges}.
1501 @cindex transactions
1502 The command provides the obvious install, remove, and upgrade
1503 operations. Each invocation is actually a @emph{transaction}: either
1504 the specified operation succeeds, or nothing happens. Thus, if the
1505 @command{guix package} process is terminated during the transaction,
1506 or if a power outage occurs during the transaction, then the user's
1507 profile remains in its previous state, and remains usable.
1509 In addition, any package transaction may be @emph{rolled back}. So, if,
1510 for example, an upgrade installs a new version of a package that turns
1511 out to have a serious bug, users may roll back to the previous instance
1512 of their profile, which was known to work well. Similarly, the global
1513 system configuration on GuixSD is subject to
1514 transactional upgrades and roll-back
1515 (@pxref{Using the Configuration System}).
1517 All packages in the package store may be @emph{garbage-collected}.
1518 Guix can determine which packages are still referenced by user
1519 profiles, and remove those that are provably no longer referenced
1520 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1521 generations of their profile so that the packages they refer to can be
1524 @cindex reproducibility
1525 @cindex reproducible builds
1526 Finally, Guix takes a @dfn{purely functional} approach to package
1527 management, as described in the introduction (@pxref{Introduction}).
1528 Each @file{/gnu/store} package directory name contains a hash of all the
1529 inputs that were used to build that package---compiler, libraries, build
1530 scripts, etc. This direct correspondence allows users to make sure a
1531 given package installation matches the current state of their
1532 distribution. It also helps maximize @dfn{build reproducibility}:
1533 thanks to the isolated build environments that are used, a given build
1534 is likely to yield bit-identical files when performed on different
1535 machines (@pxref{Invoking guix-daemon, container}).
1538 This foundation allows Guix to support @dfn{transparent binary/source
1539 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1540 available from an external source---a @dfn{substitute}, Guix just
1541 downloads it and unpacks it;
1542 otherwise, it builds the package from source, locally
1543 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1544 reproducible, users do not have to trust servers that provide
1545 substitutes: they can force a local build and @emph{challenge} providers
1546 (@pxref{Invoking guix challenge}).
1548 Control over the build environment is a feature that is also useful for
1549 developers. The @command{guix environment} command allows developers of
1550 a package to quickly set up the right development environment for their
1551 package, without having to manually install the dependencies of the
1552 package into their profile (@pxref{Invoking guix environment}).
1554 @node Invoking guix package
1555 @section Invoking @command{guix package}
1557 @cindex installing packages
1558 @cindex removing packages
1559 @cindex package installation
1560 @cindex package removal
1561 The @command{guix package} command is the tool that allows users to
1562 install, upgrade, and remove packages, as well as rolling back to
1563 previous configurations. It operates only on the user's own profile,
1564 and works with normal user privileges (@pxref{Features}). Its syntax
1568 guix package @var{options}
1570 @cindex transactions
1571 Primarily, @var{options} specifies the operations to be performed during
1572 the transaction. Upon completion, a new profile is created, but
1573 previous @dfn{generations} of the profile remain available, should the user
1576 For example, to remove @code{lua} and install @code{guile} and
1577 @code{guile-cairo} in a single transaction:
1580 guix package -r lua -i guile guile-cairo
1583 @command{guix package} also supports a @dfn{declarative approach}
1584 whereby the user specifies the exact set of packages to be available and
1585 passes it @i{via} the @option{--manifest} option
1586 (@pxref{profile-manifest, @option{--manifest}}).
1589 For each user, a symlink to the user's default profile is automatically
1590 created in @file{$HOME/.guix-profile}. This symlink always points to the
1591 current generation of the user's default profile. Thus, users can add
1592 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1593 variable, and so on.
1594 @cindex search paths
1595 If you are not using the Guix System Distribution, consider adding the
1596 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1597 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1598 shells get all the right environment variable definitions:
1601 GUIX_PROFILE="$HOME/.guix-profile" \
1602 source "$HOME/.guix-profile/etc/profile"
1605 In a multi-user setup, user profiles are stored in a place registered as
1606 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1607 to (@pxref{Invoking guix gc}). That directory is normally
1608 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1609 @var{localstatedir} is the value passed to @code{configure} as
1610 @code{--localstatedir}, and @var{user} is the user name. The
1611 @file{per-user} directory is created when @command{guix-daemon} is
1612 started, and the @var{user} sub-directory is created by @command{guix
1615 The @var{options} can be among the following:
1619 @item --install=@var{package} @dots{}
1620 @itemx -i @var{package} @dots{}
1621 Install the specified @var{package}s.
1623 Each @var{package} may specify either a simple package name, such as
1624 @code{guile}, or a package name followed by an at-sign and version number,
1625 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1626 case, the newest version prefixed by @code{1.8} is selected.)
1628 If no version number is specified, the
1629 newest available version will be selected. In addition, @var{package}
1630 may contain a colon, followed by the name of one of the outputs of the
1631 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1632 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1633 name (and optionally version) are searched for among the GNU
1634 distribution modules (@pxref{Package Modules}).
1636 @cindex propagated inputs
1637 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1638 that automatically get installed along with the required package
1639 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1640 @code{package} objects}, for information about propagated inputs in
1641 package definitions).
1643 @anchor{package-cmd-propagated-inputs}
1644 An example is the GNU MPC library: its C header files refer to those of
1645 the GNU MPFR library, which in turn refer to those of the GMP library.
1646 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1647 in the profile; removing MPC also removes MPFR and GMP---unless they had
1648 also been explicitly installed by the user.
1650 Besides, packages sometimes rely on the definition of environment
1651 variables for their search paths (see explanation of
1652 @code{--search-paths} below). Any missing or possibly incorrect
1653 environment variable definitions are reported here.
1655 @item --install-from-expression=@var{exp}
1657 Install the package @var{exp} evaluates to.
1659 @var{exp} must be a Scheme expression that evaluates to a
1660 @code{<package>} object. This option is notably useful to disambiguate
1661 between same-named variants of a package, with expressions such as
1662 @code{(@@ (gnu packages base) guile-final)}.
1664 Note that this option installs the first output of the specified
1665 package, which may be insufficient when needing a specific output of a
1666 multiple-output package.
1668 @item --install-from-file=@var{file}
1669 @itemx -f @var{file}
1670 Install the package that the code within @var{file} evaluates to.
1672 As an example, @var{file} might contain a definition like this
1673 (@pxref{Defining Packages}):
1676 @verbatiminclude package-hello.scm
1679 Developers may find it useful to include such a @file{guix.scm} file
1680 in the root of their project source tree that can be used to test
1681 development snapshots and create reproducible development environments
1682 (@pxref{Invoking guix environment}).
1684 @item --remove=@var{package} @dots{}
1685 @itemx -r @var{package} @dots{}
1686 Remove the specified @var{package}s.
1688 As for @code{--install}, each @var{package} may specify a version number
1689 and/or output name in addition to the package name. For instance,
1690 @code{-r glibc:debug} would remove the @code{debug} output of
1693 @item --upgrade[=@var{regexp} @dots{}]
1694 @itemx -u [@var{regexp} @dots{}]
1695 @cindex upgrading packages
1696 Upgrade all the installed packages. If one or more @var{regexp}s are
1697 specified, upgrade only installed packages whose name matches a
1698 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1700 Note that this upgrades package to the latest version of packages found
1701 in the distribution currently installed. To update your distribution,
1702 you should regularly run @command{guix pull} (@pxref{Invoking guix
1705 @item --do-not-upgrade[=@var{regexp} @dots{}]
1706 When used together with the @code{--upgrade} option, do @emph{not}
1707 upgrade any packages whose name matches a @var{regexp}. For example, to
1708 upgrade all packages in the current profile except those containing the
1709 substring ``emacs'':
1712 $ guix package --upgrade . --do-not-upgrade emacs
1715 @item @anchor{profile-manifest}--manifest=@var{file}
1716 @itemx -m @var{file}
1717 @cindex profile declaration
1718 @cindex profile manifest
1719 Create a new generation of the profile from the manifest object
1720 returned by the Scheme code in @var{file}.
1722 This allows you to @emph{declare} the profile's contents rather than
1723 constructing it through a sequence of @code{--install} and similar
1724 commands. The advantage is that @var{file} can be put under version
1725 control, copied to different machines to reproduce the same profile, and
1728 @c FIXME: Add reference to (guix profile) documentation when available.
1729 @var{file} must return a @dfn{manifest} object, which is roughly a list
1732 @findex packages->manifest
1734 (use-package-modules guile emacs)
1739 ;; Use a specific package output.
1740 (list guile-2.0 "debug")))
1743 @findex specification->package+output
1744 In this example we have to know which modules define the @code{emacs}
1745 and @code{guile-2.0} variables to provide the right
1746 @code{use-package-modules} line, which can be cumbersome. We can
1747 instead provide regular package specifications and let
1748 @code{specification->package-output} look up the corresponding package
1753 (map (compose list specification->package+output)
1754 '("emacs" "guile@@2.0" "guile@@2.0:debug")))
1758 @cindex rolling back
1759 @cindex undoing transactions
1760 @cindex transactions, undoing
1761 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1762 the last transaction.
1764 When combined with options such as @code{--install}, roll back occurs
1765 before any other actions.
1767 When rolling back from the first generation that actually contains
1768 installed packages, the profile is made to point to the @dfn{zeroth
1769 generation}, which contains no files apart from its own metadata.
1771 After having rolled back, installing, removing, or upgrading packages
1772 overwrites previous future generations. Thus, the history of the
1773 generations in a profile is always linear.
1775 @item --switch-generation=@var{pattern}
1776 @itemx -S @var{pattern}
1778 Switch to a particular generation defined by @var{pattern}.
1780 @var{pattern} may be either a generation number or a number prefixed
1781 with ``+'' or ``-''. The latter means: move forward/backward by a
1782 specified number of generations. For example, if you want to return to
1783 the latest generation after @code{--roll-back}, use
1784 @code{--switch-generation=+1}.
1786 The difference between @code{--roll-back} and
1787 @code{--switch-generation=-1} is that @code{--switch-generation} will
1788 not make a zeroth generation, so if a specified generation does not
1789 exist, the current generation will not be changed.
1791 @item --search-paths[=@var{kind}]
1792 @cindex search paths
1793 Report environment variable definitions, in Bash syntax, that may be
1794 needed in order to use the set of installed packages. These environment
1795 variables are used to specify @dfn{search paths} for files used by some
1796 of the installed packages.
1798 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1799 environment variables to be defined so it can look for headers and
1800 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1801 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1802 library are installed in the profile, then @code{--search-paths} will
1803 suggest setting these variables to @code{@var{profile}/include} and
1804 @code{@var{profile}/lib}, respectively.
1806 The typical use case is to define these environment variables in the
1810 $ eval `guix package --search-paths`
1813 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1814 meaning that the returned environment variable definitions will either
1815 be exact settings, or prefixes or suffixes of the current value of these
1816 variables. When omitted, @var{kind} defaults to @code{exact}.
1818 This option can also be used to compute the @emph{combined} search paths
1819 of several profiles. Consider this example:
1822 $ guix package -p foo -i guile
1823 $ guix package -p bar -i guile-json
1824 $ guix package -p foo -p bar --search-paths
1827 The last command above reports about the @code{GUILE_LOAD_PATH}
1828 variable, even though, taken individually, neither @file{foo} nor
1829 @file{bar} would lead to that recommendation.
1832 @item --profile=@var{profile}
1833 @itemx -p @var{profile}
1834 Use @var{profile} instead of the user's default profile.
1837 Produce verbose output. In particular, emit the build log of the
1838 environment on the standard error port.
1841 Use the bootstrap Guile to build the profile. This option is only
1842 useful to distribution developers.
1846 In addition to these actions, @command{guix package} supports the
1847 following options to query the current state of a profile, or the
1848 availability of packages:
1852 @item --search=@var{regexp}
1853 @itemx -s @var{regexp}
1854 @cindex searching for packages
1855 List the available packages whose name, synopsis, or description matches
1856 @var{regexp}. Print all the metadata of matching packages in
1857 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1858 GNU recutils manual}).
1860 This allows specific fields to be extracted using the @command{recsel}
1861 command, for instance:
1864 $ guix package -s malloc | recsel -p name,version
1872 Similarly, to show the name of all the packages available under the
1873 terms of the GNU@tie{}LGPL version 3:
1876 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1883 It is also possible to refine search results using several @code{-s}
1884 flags. For example, the following command returns a list of board
1888 $ guix package -s '\<board\>' -s game | recsel -p name
1893 If we were to omit @code{-s game}, we would also get software packages
1894 that deal with printed circuit boards; removing the angle brackets
1895 around @code{board} would further add packages that have to do with
1898 And now for a more elaborate example. The following command searches
1899 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1900 libraries, and prints the name and synopsis of the matching packages:
1903 $ guix package -s crypto -s library | \
1904 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1908 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1909 information on @dfn{selection expressions} for @code{recsel -e}.
1911 @item --show=@var{package}
1912 Show details about @var{package}, taken from the list of available packages, in
1913 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1917 $ guix package --show=python | recsel -p name,version
1925 You may also specify the full name of a package to only get details about a
1926 specific version of it:
1928 $ guix package --show=python@@3.4 | recsel -p name,version
1935 @item --list-installed[=@var{regexp}]
1936 @itemx -I [@var{regexp}]
1937 List the currently installed packages in the specified profile, with the
1938 most recently installed packages shown last. When @var{regexp} is
1939 specified, list only installed packages whose name matches @var{regexp}.
1941 For each installed package, print the following items, separated by
1942 tabs: the package name, its version string, the part of the package that
1943 is installed (for instance, @code{out} for the default output,
1944 @code{include} for its headers, etc.), and the path of this package in
1947 @item --list-available[=@var{regexp}]
1948 @itemx -A [@var{regexp}]
1949 List packages currently available in the distribution for this system
1950 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
1951 installed packages whose name matches @var{regexp}.
1953 For each package, print the following items separated by tabs: its name,
1954 its version string, the parts of the package (@pxref{Packages with
1955 Multiple Outputs}), and the source location of its definition.
1957 @item --list-generations[=@var{pattern}]
1958 @itemx -l [@var{pattern}]
1960 Return a list of generations along with their creation dates; for each
1961 generation, show the installed packages, with the most recently
1962 installed packages shown last. Note that the zeroth generation is never
1965 For each installed package, print the following items, separated by
1966 tabs: the name of a package, its version string, the part of the package
1967 that is installed (@pxref{Packages with Multiple Outputs}), and the
1968 location of this package in the store.
1970 When @var{pattern} is used, the command returns only matching
1971 generations. Valid patterns include:
1974 @item @emph{Integers and comma-separated integers}. Both patterns denote
1975 generation numbers. For instance, @code{--list-generations=1} returns
1978 And @code{--list-generations=1,8,2} outputs three generations in the
1979 specified order. Neither spaces nor trailing commas are allowed.
1981 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
1982 specified generations and everything in between. Note that the start of
1983 a range must be smaller than its end.
1985 It is also possible to omit the endpoint. For example,
1986 @code{--list-generations=2..}, returns all generations starting from the
1989 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
1990 or months by passing an integer along with the first letter of the
1991 duration. For example, @code{--list-generations=20d} lists generations
1992 that are up to 20 days old.
1995 @item --delete-generations[=@var{pattern}]
1996 @itemx -d [@var{pattern}]
1997 When @var{pattern} is omitted, delete all generations except the current
2000 This command accepts the same patterns as @option{--list-generations}.
2001 When @var{pattern} is specified, delete the matching generations. When
2002 @var{pattern} specifies a duration, generations @emph{older} than the
2003 specified duration match. For instance, @code{--delete-generations=1m}
2004 deletes generations that are more than one month old.
2006 If the current generation matches, it is @emph{not} deleted. Also, the
2007 zeroth generation is never deleted.
2009 Note that deleting generations prevents rolling back to them.
2010 Consequently, this command must be used with care.
2014 Finally, since @command{guix package} may actually start build
2015 processes, it supports all the common build options (@pxref{Common Build
2016 Options}). It also supports package transformation options, such as
2017 @option{--with-source} (@pxref{Package Transformation Options}).
2018 However, note that package transformations are lost when upgrading; to
2019 preserve transformations across upgrades, you should define your own
2020 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
2021 (@pxref{Defining Packages}).
2025 @section Substitutes
2028 @cindex pre-built binaries
2029 Guix supports transparent source/binary deployment, which means that it
2030 can either build things locally, or download pre-built items from a
2031 server. We call these pre-built items @dfn{substitutes}---they are
2032 substitutes for local build results. In many cases, downloading a
2033 substitute is much faster than building things locally.
2035 Substitutes can be anything resulting from a derivation build
2036 (@pxref{Derivations}). Of course, in the common case, they are
2037 pre-built package binaries, but source tarballs, for instance, which
2038 also result from derivation builds, can be available as substitutes.
2040 The @code{hydra.gnu.org} server is a front-end to a build farm that
2041 builds packages from the GNU distribution continuously for some
2042 architectures, and makes them available as substitutes. This is the
2043 default source of substitutes; it can be overridden by passing the
2044 @option{--substitute-urls} option either to @command{guix-daemon}
2045 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2046 or to client tools such as @command{guix package}
2047 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2050 Substitute URLs can be either HTTP or HTTPS.
2051 HTTPS is recommended because communications are encrypted; conversely,
2052 using HTTP makes all communications visible to an eavesdropper, who
2053 could use the information gathered to determine, for instance, whether
2054 your system has unpatched security vulnerabilities.
2057 @cindex digital signatures
2058 @cindex substitutes, authorization thereof
2059 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2061 must add its public key to the access control list (ACL) of archive
2062 imports, using the @command{guix archive} command (@pxref{Invoking guix
2063 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2064 be compromised and to serve genuine substitutes.
2066 This public key is installed along with Guix, in
2067 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2068 the installation prefix of Guix. If you installed Guix from source,
2069 make sure you checked the GPG signature of
2070 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2071 Then, you can run something like this:
2074 # guix archive --authorize < hydra.gnu.org.pub
2077 Once this is in place, the output of a command like @code{guix build}
2078 should change from something like:
2081 $ guix build emacs --dry-run
2082 The following derivations would be built:
2083 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2084 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2085 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2086 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2094 $ guix build emacs --dry-run
2095 The following files would be downloaded:
2096 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2097 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2098 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2099 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2104 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2105 will be downloaded, when possible, for future builds.
2107 Guix ignores substitutes that are not signed, or that are not signed by
2108 one of the keys listed in the ACL. It also detects and raises an error
2109 when attempting to use a substitute that has been tampered with.
2112 Substitutes are downloaded over HTTP or HTTPS.
2113 The @code{http_proxy} environment
2114 variable can be set in the environment of @command{guix-daemon} and is
2115 honored for downloads of substitutes. Note that the value of
2116 @code{http_proxy} in the environment where @command{guix build},
2117 @command{guix package}, and other client commands are run has
2118 @emph{absolutely no effect}.
2120 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2121 (in other words, the server is not authenticated), contrary to what
2122 HTTPS clients such as Web browsers usually do. This is because Guix
2123 authenticates substitute information itself, as explained above, which
2124 is what we care about (whereas X.509 certificates are about
2125 authenticating bindings between domain names and public keys.)
2127 The substitute mechanism can be disabled globally by running
2128 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2129 guix-daemon}). It can also be disabled temporarily by passing the
2130 @code{--no-substitutes} option to @command{guix package}, @command{guix
2131 build}, and other command-line tools.
2134 @unnumberedsubsec On Trusting Binaries
2136 Today, each individual's control over their own computing is at the
2137 mercy of institutions, corporations, and groups with enough power and
2138 determination to subvert the computing infrastructure and exploit its
2139 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2140 convenient, we encourage users to also build on their own, or even run
2141 their own build farm, such that @code{hydra.gnu.org} is less of an
2142 interesting target. One way to help is by publishing the software you
2143 build using @command{guix publish} so that others have one more choice
2144 of server to download substitutes from (@pxref{Invoking guix publish}).
2146 Guix has the foundations to maximize build reproducibility
2147 (@pxref{Features}). In most cases, independent builds of a given
2148 package or derivation should yield bit-identical results. Thus, through
2149 a diverse set of independent package builds, we can strengthen the
2150 integrity of our systems. The @command{guix challenge} command aims to
2151 help users assess substitute servers, and to assist developers in
2152 finding out about non-deterministic package builds (@pxref{Invoking guix
2153 challenge}). Similarly, the @option{--check} option of @command{guix
2154 build} allows users to check whether previously-installed substitutes
2155 are genuine by rebuilding them locally (@pxref{build-check,
2156 @command{guix build --check}}).
2158 In the future, we want Guix to have support to publish and retrieve
2159 binaries to/from other users, in a peer-to-peer fashion. If you would
2160 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2163 @node Packages with Multiple Outputs
2164 @section Packages with Multiple Outputs
2166 @cindex multiple-output packages
2167 @cindex package outputs
2170 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2171 source package leads to exactly one directory in the store. When running
2172 @command{guix package -i glibc}, one installs the default output of the
2173 GNU libc package; the default output is called @code{out}, but its name
2174 can be omitted as shown in this command. In this particular case, the
2175 default output of @code{glibc} contains all the C header files, shared
2176 libraries, static libraries, Info documentation, and other supporting
2179 Sometimes it is more appropriate to separate the various types of files
2180 produced from a single source package into separate outputs. For
2181 instance, the GLib C library (used by GTK+ and related packages)
2182 installs more than 20 MiB of reference documentation as HTML pages.
2183 To save space for users who do not need it, the documentation goes to a
2184 separate output, called @code{doc}. To install the main GLib output,
2185 which contains everything but the documentation, one would run:
2188 guix package -i glib
2191 @cindex documentation
2192 The command to install its documentation is:
2195 guix package -i glib:doc
2198 Some packages install programs with different ``dependency footprints''.
2199 For instance, the WordNet package installs both command-line tools and
2200 graphical user interfaces (GUIs). The former depend solely on the C
2201 library, whereas the latter depend on Tcl/Tk and the underlying X
2202 libraries. In this case, we leave the command-line tools in the default
2203 output, whereas the GUIs are in a separate output. This allows users
2204 who do not need the GUIs to save space. The @command{guix size} command
2205 can help find out about such situations (@pxref{Invoking guix size}).
2206 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2208 There are several such multiple-output packages in the GNU distribution.
2209 Other conventional output names include @code{lib} for libraries and
2210 possibly header files, @code{bin} for stand-alone programs, and
2211 @code{debug} for debugging information (@pxref{Installing Debugging
2212 Files}). The outputs of a packages are listed in the third column of
2213 the output of @command{guix package --list-available} (@pxref{Invoking
2217 @node Invoking guix gc
2218 @section Invoking @command{guix gc}
2220 @cindex garbage collector
2222 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2223 The @command{guix gc} command allows users to explicitly run the garbage
2224 collector to reclaim space from the @file{/gnu/store} directory. It is
2225 the @emph{only} way to remove files from @file{/gnu/store}---removing
2226 files or directories manually may break it beyond repair!
2228 The garbage collector has a set of known @dfn{roots}: any file under
2229 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2230 cannot be deleted; any other file is considered @dfn{dead} and may be
2231 deleted. The set of garbage collector roots includes default user
2232 profiles, and may be augmented with @command{guix build --root}, for
2233 example (@pxref{Invoking guix build}).
2235 Prior to running @code{guix gc --collect-garbage} to make space, it is
2236 often useful to remove old generations from user profiles; that way, old
2237 package builds referenced by those generations can be reclaimed. This
2238 is achieved by running @code{guix package --delete-generations}
2239 (@pxref{Invoking guix package}).
2241 The @command{guix gc} command has three modes of operation: it can be
2242 used to garbage-collect any dead files (the default), to delete specific
2243 files (the @code{--delete} option), to print garbage-collector
2244 information, or for more advanced queries. The garbage collection
2245 options are as follows:
2248 @item --collect-garbage[=@var{min}]
2249 @itemx -C [@var{min}]
2250 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2251 sub-directories. This is the default operation when no option is
2254 When @var{min} is given, stop once @var{min} bytes have been collected.
2255 @var{min} may be a number of bytes, or it may include a unit as a
2256 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2257 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2259 When @var{min} is omitted, collect all the garbage.
2261 @item --free-space=@var{free}
2262 @itemx -F @var{free}
2263 Collect garbage until @var{free} space is available under
2264 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2265 as @code{500MiB}, as described above.
2267 When @var{free} or more is already available in @file{/gnu/store}, do
2268 nothing and exit immediately.
2272 Attempt to delete all the store files and directories specified as
2273 arguments. This fails if some of the files are not in the store, or if
2274 they are still live.
2276 @item --list-failures
2277 List store items corresponding to cached build failures.
2279 This prints nothing unless the daemon was started with
2280 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2281 @option{--cache-failures}}).
2283 @item --clear-failures
2284 Remove the specified store items from the failed-build cache.
2286 Again, this option only makes sense when the daemon is started with
2287 @option{--cache-failures}. Otherwise, it does nothing.
2290 Show the list of dead files and directories still present in the
2291 store---i.e., files and directories no longer reachable from any root.
2294 Show the list of live store files and directories.
2298 In addition, the references among existing store files can be queried:
2304 @cindex package dependencies
2305 List the references (respectively, the referrers) of store files given
2311 List the requisites of the store files passed as arguments. Requisites
2312 include the store files themselves, their references, and the references
2313 of these, recursively. In other words, the returned list is the
2314 @dfn{transitive closure} of the store files.
2316 @xref{Invoking guix size}, for a tool to profile the size of the closure
2317 of an element. @xref{Invoking guix graph}, for a tool to visualize
2318 the graph of references.
2322 Lastly, the following options allow you to check the integrity of the
2323 store and to control disk usage.
2327 @item --verify[=@var{options}]
2328 @cindex integrity, of the store
2329 @cindex integrity checking
2330 Verify the integrity of the store.
2332 By default, make sure that all the store items marked as valid in the
2333 database of the daemon actually exist in @file{/gnu/store}.
2335 When provided, @var{options} must be a comma-separated list containing one
2336 or more of @code{contents} and @code{repair}.
2338 When passing @option{--verify=contents}, the daemon computes the
2339 content hash of each store item and compares it against its hash in the
2340 database. Hash mismatches are reported as data corruptions. Because it
2341 traverses @emph{all the files in the store}, this command can take a
2342 long time, especially on systems with a slow disk drive.
2344 @cindex repairing the store
2345 @cindex corruption, recovering from
2346 Using @option{--verify=repair} or @option{--verify=contents,repair}
2347 causes the daemon to try to repair corrupt store items by fetching
2348 substitutes for them (@pxref{Substitutes}). Because repairing is not
2349 atomic, and thus potentially dangerous, it is available only to the
2350 system administrator. A lightweight alternative, when you know exactly
2351 which items in the store are corrupt, is @command{guix build --repair}
2352 (@pxref{Invoking guix build}).
2355 @cindex deduplication
2356 Optimize the store by hard-linking identical files---this is
2357 @dfn{deduplication}.
2359 The daemon performs deduplication after each successful build or archive
2360 import, unless it was started with @code{--disable-deduplication}
2361 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2362 this option is primarily useful when the daemon was running with
2363 @code{--disable-deduplication}.
2367 @node Invoking guix pull
2368 @section Invoking @command{guix pull}
2370 @cindex upgrading Guix
2371 @cindex updating Guix
2372 @cindex @command{guix pull}
2374 Packages are installed or upgraded to the latest version available in
2375 the distribution currently available on your local machine. To update
2376 that distribution, along with the Guix tools, you must run @command{guix
2377 pull}: the command downloads the latest Guix source code and package
2378 descriptions, and deploys it.
2380 On completion, @command{guix package} will use packages and package
2381 versions from this just-retrieved copy of Guix. Not only that, but all
2382 the Guix commands and Scheme modules will also be taken from that latest
2383 version. New @command{guix} sub-commands added by the update also
2386 Any user can update their Guix copy using @command{guix pull}, and the
2387 effect is limited to the user who run @command{guix pull}. For
2388 instance, when user @code{root} runs @command{guix pull}, this has no
2389 effect on the version of Guix that user @code{alice} sees, and vice
2390 versa@footnote{Under the hood, @command{guix pull} updates the
2391 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2392 and the @command{guix} command loads code from there. Currently, the
2393 only way to roll back an invocation of @command{guix pull} is to
2394 manually update this symlink to point to the previous Guix.}.
2396 The @command{guix pull} command is usually invoked with no arguments,
2397 but it supports the following options:
2401 Produce verbose output, writing build logs to the standard error output.
2403 @item --url=@var{url}
2404 Download the source tarball of Guix from @var{url}.
2406 By default, the tarball is taken from its canonical address at
2407 @code{gnu.org}, for the stable branch of Guix.
2409 With some Git servers, this can be used to deploy any version of Guix.
2410 For example, to download and deploy version 0.12.0 of Guix from the
2414 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.12.0.tar.gz
2417 It can also be used to deploy arbitrary Git revisions:
2420 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/74d862e8a.tar.gz
2424 Use the bootstrap Guile to build the latest Guix. This option is only
2425 useful to Guix developers.
2428 In addition, @command{guix pull} supports all the common build options
2429 (@pxref{Common Build Options}).
2431 @node Invoking guix pack
2432 @section Invoking @command{guix pack}
2434 Occasionally you want to pass software to people who are not (yet!)
2435 lucky enough to be using Guix. You'd tell them to run @command{guix
2436 package -i @var{something}}, but that's not possible in this case. This
2437 is where @command{guix pack} comes in.
2441 @cindex application bundle
2442 @cindex software bundle
2443 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2444 @dfn{software bundle}: it creates a tarball or some other archive
2445 containing the binaries of the software you're interested in, and all
2446 its dependencies. The resulting archive can be used on any machine that
2447 does not have Guix, and people can run the exact same binaries as those
2448 you have with Guix. The pack itself is created in a bit-reproducible
2449 fashion, so anyone can verify that it really contains the build results
2450 that you pretend to be shipping.
2452 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2453 their dependencies, you can run:
2456 $ guix pack guile emacs geiser
2458 /gnu/store/@dots{}-pack.tar.gz
2461 The result here is a tarball containing a @file{/gnu/store} directory
2462 with all the relevant packages. The resulting tarball contains a
2463 @dfn{profile} with the three packages of interest; the profile is the
2464 same as would be created by @command{guix package -i}. It is this
2465 mechanism that is used to create Guix's own standalone binary tarball
2466 (@pxref{Binary Installation}).
2468 Users of this pack would have to run
2469 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2470 find inconvenient. To work around it, you can create, say, a
2471 @file{/opt/gnu/bin} symlink to the profile:
2474 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2478 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2480 Alternatively, you can produce a pack in the Docker image format using
2481 the following command:
2484 guix pack -f docker guile emacs geiser
2488 The result is a tarball that can be passed to the @command{docker load}
2490 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2491 documentation} for more information.
2493 Several command-line options allow you to customize your pack:
2496 @item --format=@var{format}
2497 @itemx -f @var{format}
2498 Produce a pack in the given @var{format}.
2500 The available formats are:
2504 This is the default format. It produces a tarball containing all the
2505 specifies binaries and symlinks.
2508 This produces a tarball that follows the
2509 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2510 Docker Image Specification}.
2513 @item --expression=@var{expr}
2514 @itemx -e @var{expr}
2515 Consider the package @var{expr} evaluates to.
2517 This has the same purpose as the same-named option in @command{guix
2518 build} (@pxref{Additional Build Options, @code{--expression} in
2519 @command{guix build}}).
2521 @item --system=@var{system}
2522 @itemx -s @var{system}
2523 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2524 the system type of the build host.
2526 @item --target=@var{triplet}
2527 @cindex cross-compilation
2528 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2529 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2530 configuration triplets,, autoconf, Autoconf}).
2532 @item --compression=@var{tool}
2533 @itemx -C @var{tool}
2534 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2535 @code{bzip2}, @code{xz}, or @code{lzip}.
2537 @item --symlink=@var{spec}
2538 @itemx -S @var{spec}
2539 Add the symlinks specified by @var{spec} to the pack. This option can
2540 appear several times.
2542 @var{spec} has the form @code{@var{source}=@var{target}}, where
2543 @var{source} is the symlink that will be created and @var{target} is the
2546 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2547 symlink pointing to the @file{bin} sub-directory of the profile.
2549 @item --localstatedir
2550 Include the ``local state directory'', @file{/var/guix}, in the
2553 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2554 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2555 the pack means that the store is ``complete'' and manageable by Guix;
2556 not providing it pack means that the store is ``dead'': items cannot be
2557 added to it or removed from it after extraction of the pack.
2559 One use case for this is the Guix self-contained binary tarball
2560 (@pxref{Binary Installation}).
2563 In addition, @command{guix pack} supports all the common build options
2564 (@pxref{Common Build Options}) and all the package transformation
2565 options (@pxref{Package Transformation Options}).
2568 @node Invoking guix archive
2569 @section Invoking @command{guix archive}
2571 @cindex @command{guix archive}
2573 The @command{guix archive} command allows users to @dfn{export} files
2574 from the store into a single archive, and to later @dfn{import} them.
2575 In particular, it allows store files to be transferred from one machine
2576 to the store on another machine.
2578 @cindex exporting store items
2579 To export store files as an archive to standard output, run:
2582 guix archive --export @var{options} @var{specifications}...
2585 @var{specifications} may be either store file names or package
2586 specifications, as for @command{guix package} (@pxref{Invoking guix
2587 package}). For instance, the following command creates an archive
2588 containing the @code{gui} output of the @code{git} package and the main
2589 output of @code{emacs}:
2592 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2595 If the specified packages are not built yet, @command{guix archive}
2596 automatically builds them. The build process may be controlled with the
2597 common build options (@pxref{Common Build Options}).
2599 To transfer the @code{emacs} package to a machine connected over SSH,
2603 guix archive --export -r emacs | ssh the-machine guix archive --import
2607 Similarly, a complete user profile may be transferred from one machine
2608 to another like this:
2611 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2612 ssh the-machine guix-archive --import
2616 However, note that, in both examples, all of @code{emacs} and the
2617 profile as well as all of their dependencies are transferred (due to
2618 @code{-r}), regardless of what is already available in the store on the
2619 target machine. The @code{--missing} option can help figure out which
2620 items are missing from the target store. The @command{guix copy}
2621 command simplifies and optimizes this whole process, so this is probably
2622 what you should use in this case (@pxref{Invoking guix copy}).
2624 @cindex nar, archive format
2625 @cindex normalized archive (nar)
2626 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2627 comparable in spirit to `tar', but with differences
2628 that make it more appropriate for our purposes. First, rather than
2629 recording all Unix metadata for each file, the nar format only mentions
2630 the file type (regular, directory, or symbolic link); Unix permissions
2631 and owner/group are dismissed. Second, the order in which directory
2632 entries are stored always follows the order of file names according to
2633 the C locale collation order. This makes archive production fully
2636 When exporting, the daemon digitally signs the contents of the archive,
2637 and that digital signature is appended. When importing, the daemon
2638 verifies the signature and rejects the import in case of an invalid
2639 signature or if the signing key is not authorized.
2640 @c FIXME: Add xref to daemon doc about signatures.
2642 The main options are:
2646 Export the specified store files or packages (see below.) Write the
2647 resulting archive to the standard output.
2649 Dependencies are @emph{not} included in the output, unless
2650 @code{--recursive} is passed.
2654 When combined with @code{--export}, this instructs @command{guix
2655 archive} to include dependencies of the given items in the archive.
2656 Thus, the resulting archive is self-contained: it contains the closure
2657 of the exported store items.
2660 Read an archive from the standard input, and import the files listed
2661 therein into the store. Abort if the archive has an invalid digital
2662 signature, or if it is signed by a public key not among the authorized
2663 keys (see @code{--authorize} below.)
2666 Read a list of store file names from the standard input, one per line,
2667 and write on the standard output the subset of these files missing from
2670 @item --generate-key[=@var{parameters}]
2671 @cindex signing, archives
2672 Generate a new key pair for the daemon. This is a prerequisite before
2673 archives can be exported with @code{--export}. Note that this operation
2674 usually takes time, because it needs to gather enough entropy to
2675 generate the key pair.
2677 The generated key pair is typically stored under @file{/etc/guix}, in
2678 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2679 key, which must be kept secret.) When @var{parameters} is omitted,
2680 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2681 versions before 1.6.0, it is a 4096-bit RSA key.
2682 Alternatively, @var{parameters} can specify
2683 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2684 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2685 Libgcrypt Reference Manual}).
2688 @cindex authorizing, archives
2689 Authorize imports signed by the public key passed on standard input.
2690 The public key must be in ``s-expression advanced format''---i.e., the
2691 same format as the @file{signing-key.pub} file.
2693 The list of authorized keys is kept in the human-editable file
2694 @file{/etc/guix/acl}. The file contains
2695 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2696 s-expressions''} and is structured as an access-control list in the
2697 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2700 @item --extract=@var{directory}
2701 @itemx -x @var{directory}
2702 Read a single-item archive as served by substitute servers
2703 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2704 low-level operation needed in only very narrow use cases; see below.
2706 For example, the following command extracts the substitute for Emacs
2707 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2711 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2712 | bunzip2 | guix archive -x /tmp/emacs
2715 Single-item archives are different from multiple-item archives produced
2716 by @command{guix archive --export}; they contain a single store item,
2717 and they do @emph{not} embed a signature. Thus this operation does
2718 @emph{no} signature verification and its output should be considered
2721 The primary purpose of this operation is to facilitate inspection of
2722 archive contents coming from possibly untrusted substitute servers.
2726 @c *********************************************************************
2727 @node Programming Interface
2728 @chapter Programming Interface
2730 GNU Guix provides several Scheme programming interfaces (APIs) to
2731 define, build, and query packages. The first interface allows users to
2732 write high-level package definitions. These definitions refer to
2733 familiar packaging concepts, such as the name and version of a package,
2734 its build system, and its dependencies. These definitions can then be
2735 turned into concrete build actions.
2737 Build actions are performed by the Guix daemon, on behalf of users. In a
2738 standard setup, the daemon has write access to the store---the
2739 @file{/gnu/store} directory---whereas users do not. The recommended
2740 setup also has the daemon perform builds in chroots, under a specific
2741 build users, to minimize interference with the rest of the system.
2744 Lower-level APIs are available to interact with the daemon and the
2745 store. To instruct the daemon to perform a build action, users actually
2746 provide it with a @dfn{derivation}. A derivation is a low-level
2747 representation of the build actions to be taken, and the environment in
2748 which they should occur---derivations are to package definitions what
2749 assembly is to C programs. The term ``derivation'' comes from the fact
2750 that build results @emph{derive} from them.
2752 This chapter describes all these APIs in turn, starting from high-level
2753 package definitions.
2756 * Defining Packages:: Defining new packages.
2757 * Build Systems:: Specifying how packages are built.
2758 * The Store:: Manipulating the package store.
2759 * Derivations:: Low-level interface to package derivations.
2760 * The Store Monad:: Purely functional interface to the store.
2761 * G-Expressions:: Manipulating build expressions.
2764 @node Defining Packages
2765 @section Defining Packages
2767 The high-level interface to package definitions is implemented in the
2768 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2769 example, the package definition, or @dfn{recipe}, for the GNU Hello
2770 package looks like this:
2773 (define-module (gnu packages hello)
2774 #:use-module (guix packages)
2775 #:use-module (guix download)
2776 #:use-module (guix build-system gnu)
2777 #:use-module (guix licenses)
2778 #:use-module (gnu packages gawk))
2780 (define-public hello
2786 (uri (string-append "mirror://gnu/hello/hello-" version
2790 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2791 (build-system gnu-build-system)
2792 (arguments '(#:configure-flags '("--enable-silent-rules")))
2793 (inputs `(("gawk" ,gawk)))
2794 (synopsis "Hello, GNU world: An example GNU package")
2795 (description "Guess what GNU Hello prints!")
2796 (home-page "http://www.gnu.org/software/hello/")
2801 Without being a Scheme expert, the reader may have guessed the meaning
2802 of the various fields here. This expression binds the variable
2803 @code{hello} to a @code{<package>} object, which is essentially a record
2804 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2805 This package object can be inspected using procedures found in the
2806 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2807 returns---surprise!---@code{"hello"}.
2809 With luck, you may be able to import part or all of the definition of
2810 the package you are interested in from another repository, using the
2811 @code{guix import} command (@pxref{Invoking guix import}).
2813 In the example above, @var{hello} is defined in a module of its own,
2814 @code{(gnu packages hello)}. Technically, this is not strictly
2815 necessary, but it is convenient to do so: all the packages defined in
2816 modules under @code{(gnu packages @dots{})} are automatically known to
2817 the command-line tools (@pxref{Package Modules}).
2819 There are a few points worth noting in the above package definition:
2823 The @code{source} field of the package is an @code{<origin>} object
2824 (@pxref{origin Reference}, for the complete reference).
2825 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2826 meaning that the source is a file to be downloaded over FTP or HTTP.
2828 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2829 the GNU mirrors defined in @code{(guix download)}.
2831 The @code{sha256} field specifies the expected SHA256 hash of the file
2832 being downloaded. It is mandatory, and allows Guix to check the
2833 integrity of the file. The @code{(base32 @dots{})} form introduces the
2834 base32 representation of the hash. You can obtain this information with
2835 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2836 hash} (@pxref{Invoking guix hash}).
2839 When needed, the @code{origin} form can also have a @code{patches} field
2840 listing patches to be applied, and a @code{snippet} field giving a
2841 Scheme expression to modify the source code.
2844 @cindex GNU Build System
2845 The @code{build-system} field specifies the procedure to build the
2846 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2847 represents the familiar GNU Build System, where packages may be
2848 configured, built, and installed with the usual @code{./configure &&
2849 make && make check && make install} command sequence.
2852 The @code{arguments} field specifies options for the build system
2853 (@pxref{Build Systems}). Here it is interpreted by
2854 @var{gnu-build-system} as a request run @file{configure} with the
2855 @code{--enable-silent-rules} flag.
2861 What about these quote (@code{'}) characters? They are Scheme syntax to
2862 introduce a literal list; @code{'} is synonymous with @code{quote}.
2863 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2864 for details. Here the value of the @code{arguments} field is a list of
2865 arguments passed to the build system down the road, as with @code{apply}
2866 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2869 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2870 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2871 @code{#:configure-flags} is a keyword used to pass a keyword argument
2872 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2876 The @code{inputs} field specifies inputs to the build process---i.e.,
2877 build-time or run-time dependencies of the package. Here, we define an
2878 input called @code{"gawk"} whose value is that of the @var{gawk}
2879 variable; @var{gawk} is itself bound to a @code{<package>} object.
2881 @cindex backquote (quasiquote)
2884 @cindex comma (unquote)
2888 @findex unquote-splicing
2889 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2890 us to introduce a literal list in the @code{inputs} field, while
2891 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2892 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2895 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2896 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2897 of ensuring that they are present (@pxref{Build Systems}).
2899 However, any other dependencies need to be specified in the
2900 @code{inputs} field. Any dependency not specified here will simply be
2901 unavailable to the build process, possibly leading to a build failure.
2904 @xref{package Reference}, for a full description of possible fields.
2906 Once a package definition is in place, the
2907 package may actually be built using the @code{guix build} command-line
2908 tool (@pxref{Invoking guix build}), troubleshooting any build failures
2909 you encounter (@pxref{Debugging Build Failures}). You can easily jump back to the
2910 package definition using the @command{guix edit} command
2911 (@pxref{Invoking guix edit}).
2912 @xref{Packaging Guidelines}, for
2913 more information on how to test package definitions, and
2914 @ref{Invoking guix lint}, for information on how to check a definition
2915 for style conformance.
2916 @vindex GUIX_PACKAGE_PATH
2917 Lastly, @pxref{Package Modules}, for information
2918 on how to extend the distribution by adding your own package definitions
2919 to @code{GUIX_PACKAGE_PATH}.
2921 Finally, updating the package definition to a new upstream version
2922 can be partly automated by the @command{guix refresh} command
2923 (@pxref{Invoking guix refresh}).
2925 Behind the scenes, a derivation corresponding to the @code{<package>}
2926 object is first computed by the @code{package-derivation} procedure.
2927 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
2928 The build actions it prescribes may then be realized by using the
2929 @code{build-derivations} procedure (@pxref{The Store}).
2931 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
2932 Return the @code{<derivation>} object of @var{package} for @var{system}
2933 (@pxref{Derivations}).
2935 @var{package} must be a valid @code{<package>} object, and @var{system}
2936 must be a string denoting the target system type---e.g.,
2937 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
2938 must be a connection to the daemon, which operates on the store
2939 (@pxref{The Store}).
2943 @cindex cross-compilation
2944 Similarly, it is possible to compute a derivation that cross-builds a
2945 package for some other system:
2947 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
2948 @var{package} @var{target} [@var{system}]
2949 Return the @code{<derivation>} object of @var{package} cross-built from
2950 @var{system} to @var{target}.
2952 @var{target} must be a valid GNU triplet denoting the target hardware
2953 and operating system, such as @code{"mips64el-linux-gnu"}
2954 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
2955 Configure and Build System}).
2958 @cindex package transformations
2959 @cindex input rewriting
2960 @cindex dependency tree rewriting
2961 Packages can be manipulated in arbitrary ways. An example of a useful
2962 transformation is @dfn{input rewriting}, whereby the dependency tree of
2963 a package is rewritten by replacing specific inputs by others:
2965 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
2966 [@var{rewrite-name}]
2967 Return a procedure that, when passed a package, replaces its direct and
2968 indirect dependencies (but not its implicit inputs) according to
2969 @var{replacements}. @var{replacements} is a list of package pairs; the
2970 first element of each pair is the package to replace, and the second one
2973 Optionally, @var{rewrite-name} is a one-argument procedure that takes
2974 the name of a package and returns its new name after rewrite.
2978 Consider this example:
2981 (define libressl-instead-of-openssl
2982 ;; This is a procedure to replace OPENSSL by LIBRESSL,
2984 (package-input-rewriting `((,openssl . ,libressl))))
2986 (define git-with-libressl
2987 (libressl-instead-of-openssl git))
2991 Here we first define a rewriting procedure that replaces @var{openssl}
2992 with @var{libressl}. Then we use it to define a @dfn{variant} of the
2993 @var{git} package that uses @var{libressl} instead of @var{openssl}.
2994 This is exactly what the @option{--with-input} command-line option does
2995 (@pxref{Package Transformation Options, @option{--with-input}}).
2997 A more generic procedure to rewrite a package dependency graph is
2998 @code{package-mapping}: it supports arbitrary changes to nodes in the
3001 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
3002 Return a procedure that, given a package, applies @var{proc} to all the packages
3003 depended on and returns the resulting package. The procedure stops recursion
3004 when @var{cut?} returns true for a given package.
3008 * package Reference :: The package data type.
3009 * origin Reference:: The origin data type.
3013 @node package Reference
3014 @subsection @code{package} Reference
3016 This section summarizes all the options available in @code{package}
3017 declarations (@pxref{Defining Packages}).
3019 @deftp {Data Type} package
3020 This is the data type representing a package recipe.
3024 The name of the package, as a string.
3026 @item @code{version}
3027 The version of the package, as a string.
3030 An object telling how the source code for the package should be
3031 acquired. Most of the time, this is an @code{origin} object, which
3032 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3033 can also be any other ``file-like'' object such as a @code{local-file},
3034 which denotes a file from the local file system (@pxref{G-Expressions,
3035 @code{local-file}}).
3037 @item @code{build-system}
3038 The build system that should be used to build the package (@pxref{Build
3041 @item @code{arguments} (default: @code{'()})
3042 The arguments that should be passed to the build system. This is a
3043 list, typically containing sequential keyword-value pairs.
3045 @item @code{inputs} (default: @code{'()})
3046 @itemx @code{native-inputs} (default: @code{'()})
3047 @itemx @code{propagated-inputs} (default: @code{'()})
3048 @cindex inputs, of packages
3049 These fields list dependencies of the package. Each one is a list of
3050 tuples, where each tuple has a label for the input (a string) as its
3051 first element, a package, origin, or derivation as its second element,
3052 and optionally the name of the output thereof that should be used, which
3053 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3054 more on package outputs). For example, the list below specifies three
3058 `(("libffi" ,libffi)
3059 ("libunistring" ,libunistring)
3060 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3063 @cindex cross compilation, package dependencies
3064 The distinction between @code{native-inputs} and @code{inputs} is
3065 necessary when considering cross-compilation. When cross-compiling,
3066 dependencies listed in @code{inputs} are built for the @emph{target}
3067 architecture; conversely, dependencies listed in @code{native-inputs}
3068 are built for the architecture of the @emph{build} machine.
3070 @code{native-inputs} is typically used to list tools needed at
3071 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3072 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3073 this area (@pxref{Invoking guix lint}).
3075 @anchor{package-propagated-inputs}
3076 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3077 specified packages will be automatically installed alongside the package
3078 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3079 package}}, for information on how @command{guix package} deals with
3082 For example this is necessary when a C/C++ library needs headers of
3083 another library to compile, or when a pkg-config file refers to another
3084 one @i{via} its @code{Requires} field.
3086 Another example where @code{propagated-inputs} is useful is for languages
3087 that lack a facility to record the run-time search path akin to the
3088 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3089 more. To ensure that libraries written in those languages can find
3090 library code they depend on at run time, run-time dependencies must be
3091 listed in @code{propagated-inputs} rather than @code{inputs}.
3093 @item @code{self-native-input?} (default: @code{#f})
3094 This is a Boolean field telling whether the package should use itself as
3095 a native input when cross-compiling.
3097 @item @code{outputs} (default: @code{'("out")})
3098 The list of output names of the package. @xref{Packages with Multiple
3099 Outputs}, for typical uses of additional outputs.
3101 @item @code{native-search-paths} (default: @code{'()})
3102 @itemx @code{search-paths} (default: @code{'()})
3103 A list of @code{search-path-specification} objects describing
3104 search-path environment variables honored by the package.
3106 @item @code{replacement} (default: @code{#f})
3107 This must be either @code{#f} or a package object that will be used as a
3108 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3111 @item @code{synopsis}
3112 A one-line description of the package.
3114 @item @code{description}
3115 A more elaborate description of the package.
3117 @item @code{license}
3118 @cindex license, of packages
3119 The license of the package; a value from @code{(guix licenses)},
3120 or a list of such values.
3122 @item @code{home-page}
3123 The URL to the home-page of the package, as a string.
3125 @item @code{supported-systems} (default: @var{%supported-systems})
3126 The list of systems supported by the package, as strings of the form
3127 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3129 @item @code{maintainers} (default: @code{'()})
3130 The list of maintainers of the package, as @code{maintainer} objects.
3132 @item @code{location} (default: source location of the @code{package} form)
3133 The source location of the package. It is useful to override this when
3134 inheriting from another package, in which case this field is not
3135 automatically corrected.
3140 @node origin Reference
3141 @subsection @code{origin} Reference
3143 This section summarizes all the options available in @code{origin}
3144 declarations (@pxref{Defining Packages}).
3146 @deftp {Data Type} origin
3147 This is the data type representing a source code origin.
3151 An object containing the URI of the source. The object type depends on
3152 the @code{method} (see below). For example, when using the
3153 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3154 values are: a URL represented as a string, or a list thereof.
3157 A procedure that handles the URI.
3162 @item @var{url-fetch} from @code{(guix download)}
3163 download a file from the HTTP, HTTPS, or FTP URL specified in the
3167 @item @var{git-fetch} from @code{(guix git-download)}
3168 clone the Git version control repository, and check out the revision
3169 specified in the @code{uri} field as a @code{git-reference} object; a
3170 @code{git-reference} looks like this:
3174 (url "git://git.debian.org/git/pkg-shadow/shadow")
3175 (commit "v4.1.5.1"))
3180 A bytevector containing the SHA-256 hash of the source. Typically the
3181 @code{base32} form is used here to generate the bytevector from a
3184 You can obtain this information using @code{guix download}
3185 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3188 @item @code{file-name} (default: @code{#f})
3189 The file name under which the source code should be saved. When this is
3190 @code{#f}, a sensible default value will be used in most cases. In case
3191 the source is fetched from a URL, the file name from the URL will be
3192 used. For version control checkouts, it is recommended to provide the
3193 file name explicitly because the default is not very descriptive.
3195 @item @code{patches} (default: @code{'()})
3196 A list of file names containing patches to be applied to the source.
3198 This list of patches must be unconditional. In particular, it cannot
3199 depend on the value of @code{%current-system} or
3200 @code{%current-target-system}.
3202 @item @code{snippet} (default: @code{#f})
3203 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3204 in the source directory. This is a convenient way to modify the source,
3205 sometimes more convenient than a patch.
3207 @item @code{patch-flags} (default: @code{'("-p1")})
3208 A list of command-line flags that should be passed to the @code{patch}
3211 @item @code{patch-inputs} (default: @code{#f})
3212 Input packages or derivations to the patching process. When this is
3213 @code{#f}, the usual set of inputs necessary for patching are provided,
3214 such as GNU@tie{}Patch.
3216 @item @code{modules} (default: @code{'()})
3217 A list of Guile modules that should be loaded during the patching
3218 process and while running the code in the @code{snippet} field.
3220 @item @code{patch-guile} (default: @code{#f})
3221 The Guile package that should be used in the patching process. When
3222 this is @code{#f}, a sensible default is used.
3228 @section Build Systems
3230 @cindex build system
3231 Each package definition specifies a @dfn{build system} and arguments for
3232 that build system (@pxref{Defining Packages}). This @code{build-system}
3233 field represents the build procedure of the package, as well as implicit
3234 dependencies of that build procedure.
3236 Build systems are @code{<build-system>} objects. The interface to
3237 create and manipulate them is provided by the @code{(guix build-system)}
3238 module, and actual build systems are exported by specific modules.
3240 @cindex bag (low-level package representation)
3241 Under the hood, build systems first compile package objects to
3242 @dfn{bags}. A @dfn{bag} is like a package, but with less
3243 ornamentation---in other words, a bag is a lower-level representation of
3244 a package, which includes all the inputs of that package, including some
3245 that were implicitly added by the build system. This intermediate
3246 representation is then compiled to a derivation (@pxref{Derivations}).
3248 Build systems accept an optional list of @dfn{arguments}. In package
3249 definitions, these are passed @i{via} the @code{arguments} field
3250 (@pxref{Defining Packages}). They are typically keyword arguments
3251 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3252 Guile Reference Manual}). The value of these arguments is usually
3253 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3254 by the daemon (@pxref{Derivations}).
3256 The main build system is @var{gnu-build-system}, which implements the
3257 standard build procedure for GNU and many other packages. It
3258 is provided by the @code{(guix build-system gnu)} module.
3260 @defvr {Scheme Variable} gnu-build-system
3261 @var{gnu-build-system} represents the GNU Build System, and variants
3262 thereof (@pxref{Configuration, configuration and makefile conventions,,
3263 standards, GNU Coding Standards}).
3265 @cindex build phases
3266 In a nutshell, packages using it are configured, built, and installed with
3267 the usual @code{./configure && make && make check && make install}
3268 command sequence. In practice, a few additional steps are often needed.
3269 All these steps are split up in separate @dfn{phases},
3270 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3271 modules for more details about the build phases.}:
3275 Unpack the source tarball, and change the current directory to the
3276 extracted source tree. If the source is actually a directory, copy it
3277 to the build tree, and enter that directory.
3279 @item patch-source-shebangs
3280 Patch shebangs encountered in source files so they refer to the right
3281 store file names. For instance, this changes @code{#!/bin/sh} to
3282 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3285 Run the @file{configure} script with a number of default options, such
3286 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3287 by the @code{#:configure-flags} argument.
3290 Run @code{make} with the list of flags specified with
3291 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3292 (the default), build with @code{make -j}.
3295 Run @code{make check}, or some other target specified with
3296 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3297 @code{#:parallel-tests?} argument is true (the default), run @code{make
3301 Run @code{make install} with the flags listed in @code{#:make-flags}.
3303 @item patch-shebangs
3304 Patch shebangs on the installed executable files.
3307 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3308 is false), copying them to the @code{debug} output when available
3309 (@pxref{Installing Debugging Files}).
3312 @vindex %standard-phases
3313 The build-side module @code{(guix build gnu-build-system)} defines
3314 @var{%standard-phases} as the default list of build phases.
3315 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3316 procedure implements the actual phase.
3318 The list of phases used for a particular package can be changed with the
3319 @code{#:phases} parameter. For instance, passing:
3322 #:phases (modify-phases %standard-phases (delete 'configure))
3325 means that all the phases described above will be used, except the
3326 @code{configure} phase.
3328 In addition, this build system ensures that the ``standard'' environment
3329 for GNU packages is available. This includes tools such as GCC, libc,
3330 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3331 build-system gnu)} module for a complete list). We call these the
3332 @dfn{implicit inputs} of a package, because package definitions do not
3333 have to mention them.
3336 Other @code{<build-system>} objects are defined to support other
3337 conventions and tools used by free software packages. They inherit most
3338 of @var{gnu-build-system}, and differ mainly in the set of inputs
3339 implicitly added to the build process, and in the list of phases
3340 executed. Some of these build systems are listed below.
3342 @defvr {Scheme Variable} ant-build-system
3343 This variable is exported by @code{(guix build-system ant)}. It
3344 implements the build procedure for Java packages that can be built with
3345 @url{http://ant.apache.org/, Ant build tool}.
3347 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3348 provided by the @code{icedtea} package to the set of inputs. Different
3349 packages can be specified with the @code{#:ant} and @code{#:jdk}
3350 parameters, respectively.
3352 When the original package does not provide a suitable Ant build file,
3353 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3354 build file @file{build.xml} with tasks to build the specified jar
3355 archive. In this case the parameter @code{#:source-dir} can be used to
3356 specify the source sub-directory, defaulting to ``src''.
3358 The parameter @code{#:build-target} can be used to specify the Ant task
3359 that should be run during the @code{build} phase. By default the
3360 ``jar'' task will be run.
3364 @defvr {Scheme Variable} asdf-build-system/source
3365 @defvrx {Scheme Variable} asdf-build-system/sbcl
3366 @defvrx {Scheme Variable} asdf-build-system/ecl
3368 These variables, exported by @code{(guix build-system asdf)}, implement
3369 build procedures for Common Lisp packages using
3370 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3371 definition facility for Common Lisp programs and libraries.
3373 The @code{asdf-build-system/source} system installs the packages in
3374 source form, and can be loaded using any common lisp implementation, via
3375 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3376 systems in the format which a particular implementation understands.
3377 These build systems can also be used to produce executable programs, or
3378 lisp images which contain a set of packages pre-loaded.
3380 The build system uses naming conventions. For binary packages, the
3381 package name should be prefixed with the lisp implementation, such as
3382 @code{sbcl-} for @code{asdf-build-system/sbcl}.
3384 Additionally, the corresponding source package should be labeled using
3385 the same convention as python packages (see @ref{Python Modules}), using
3386 the @code{cl-} prefix.
3388 For binary packages, each system should be defined as a Guix package.
3389 If one package @code{origin} contains several systems, package variants
3390 can be created in order to build all the systems. Source packages,
3391 which use @code{asdf-build-system/source}, may contain several systems.
3393 In order to create executable programs and images, the build-side
3394 procedures @code{build-program} and @code{build-image} can be used.
3395 They should be called in a build phase after the @code{create-symlinks}
3396 phase, so that the system which was just built can be used within the
3397 resulting image. @code{build-program} requires a list of Common Lisp
3398 expressions to be passed as the @code{#:entry-program} argument.
3400 If the system is not defined within its own @code{.asd} file of the same
3401 name, then the @code{#:asd-file} parameter should be used to specify
3402 which file the system is defined in. Furthermore, if the package
3403 defines a system for its tests in a separate file, it will be loaded
3404 before the tests are run if it is specified by the
3405 @code{#:test-asd-file} parameter. If it is not set, the files
3406 @code{<system>-tests.asd}, @code{<system>-test.asd}, @code{tests.asd},
3407 and @code{test.asd} will be tried if they exist.
3409 If for some reason the package must be named in a different way than the
3410 naming conventions suggest, the @code{#:asd-system-name} parameter can
3411 be used to specify the name of the system.
3415 @defvr {Scheme Variable} cargo-build-system
3416 @cindex Rust programming language
3417 @cindex Cargo (Rust build system)
3418 This variable is exported by @code{(guix build-system cargo)}. It
3419 supports builds of packages using Cargo, the build tool of the
3420 @uref{https://www.rust-lang.org, Rust programming language}.
3422 In its @code{configure} phase, this build system replaces dependencies
3423 specified in the @file{Carto.toml} file with inputs to the Guix package.
3424 The @code{install} phase installs the binaries, and it also installs the
3425 source code and @file{Cargo.toml} file.
3428 @defvr {Scheme Variable} cmake-build-system
3429 This variable is exported by @code{(guix build-system cmake)}. It
3430 implements the build procedure for packages using the
3431 @url{http://www.cmake.org, CMake build tool}.
3433 It automatically adds the @code{cmake} package to the set of inputs.
3434 Which package is used can be specified with the @code{#:cmake}
3437 The @code{#:configure-flags} parameter is taken as a list of flags
3438 passed to the @command{cmake} command. The @code{#:build-type}
3439 parameter specifies in abstract terms the flags passed to the compiler;
3440 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3441 debugging information''), which roughly means that code is compiled with
3442 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3445 @defvr {Scheme Variable} glib-or-gtk-build-system
3446 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3447 is intended for use with packages making use of GLib or GTK+.
3449 This build system adds the following two phases to the ones defined by
3450 @var{gnu-build-system}:
3453 @item glib-or-gtk-wrap
3454 The phase @code{glib-or-gtk-wrap} ensures that programs in
3455 @file{bin/} are able to find GLib ``schemas'' and
3456 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3457 modules}. This is achieved by wrapping the programs in launch scripts
3458 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3459 environment variables.
3461 It is possible to exclude specific package outputs from that wrapping
3462 process by listing their names in the
3463 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3464 when an output is known not to contain any GLib or GTK+ binaries, and
3465 where wrapping would gratuitously add a dependency of that output on
3468 @item glib-or-gtk-compile-schemas
3469 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3470 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3471 GSettings schemas} of GLib are compiled. Compilation is performed by the
3472 @command{glib-compile-schemas} program. It is provided by the package
3473 @code{glib:bin} which is automatically imported by the build system.
3474 The @code{glib} package providing @command{glib-compile-schemas} can be
3475 specified with the @code{#:glib} parameter.
3478 Both phases are executed after the @code{install} phase.
3481 @defvr {Scheme Variable} ocaml-build-system
3482 This variable is exported by @code{(guix build-system ocaml)}. It implements
3483 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3484 of choosing the correct set of commands to run for each package. OCaml
3485 packages can expect many different commands to be run. This build system will
3488 When the package has a @file{setup.ml} file present at the top-level, it will
3489 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3490 @code{ocaml setup.ml -install}. The build system will assume that this file
3491 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3492 care of setting the prefix and enabling tests if they are not disabled. You
3493 can pass configure and build flags with the @code{#:configure-flags} and
3494 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3495 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3496 bypass this system in the build and install phases.
3498 When the package has a @file{configure} file, it is assumed that it is a
3499 hand-made configure script that requires a different argument format than
3500 in the @code{gnu-build-system}. You can add more flags with the
3501 @code{#:configure-flags} key.
3503 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3504 @code{#t}), it will be used and more flags can be passed to the build and
3505 install phases with the @code{#:make-flags} key.
3507 Finally, some packages do not have these files and use a somewhat standard
3508 location for its build system. In that case, the build system will run
3509 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3510 providing the path to the required findlib module. Additional flags can
3511 be passed via the @code{#:build-flags} key. Install is taken care of by
3512 @command{opam-installer}. In this case, the @code{opam} package must
3513 be added to the @code{native-inputs} field of the package definition.
3515 Note that most OCaml packages assume they will be installed in the same
3516 directory as OCaml, which is not what we want in guix. In particular, they
3517 will install @file{.so} files in their module's directory, which is usually
3518 fine because it is in the OCaml compiler directory. In guix though, these
3519 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3520 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3521 @file{.so} libraries should be installed.
3524 @defvr {Scheme Variable} python-build-system
3525 This variable is exported by @code{(guix build-system python)}. It
3526 implements the more or less standard build procedure used by Python
3527 packages, which consists in running @code{python setup.py build} and
3528 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3530 For packages that install stand-alone Python programs under @code{bin/},
3531 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3532 environment variable points to all the Python libraries they depend on.
3534 Which Python package is used to perform the build can be specified with
3535 the @code{#:python} parameter. This is a useful way to force a package
3536 to be built for a specific version of the Python interpreter, which
3537 might be necessary if the package is only compatible with a single
3538 interpreter version.
3540 By default guix calls @code{setup.py} under control of
3541 @code{setuptools}, much like @command{pip} does. Some packages are not
3542 compatible with setuptools (and pip), thus you can disable this by
3543 setting the @code{#:use-setuptools} parameter to @code{#f}.
3546 @defvr {Scheme Variable} perl-build-system
3547 This variable is exported by @code{(guix build-system perl)}. It
3548 implements the standard build procedure for Perl packages, which either
3549 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3550 followed by @code{Build} and @code{Build install}; or in running
3551 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3552 @code{make} and @code{make install}, depending on which of
3553 @code{Build.PL} or @code{Makefile.PL} is present in the package
3554 distribution. Preference is given to the former if both @code{Build.PL}
3555 and @code{Makefile.PL} exist in the package distribution. This
3556 preference can be reversed by specifying @code{#t} for the
3557 @code{#:make-maker?} parameter.
3559 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3560 passes flags specified by the @code{#:make-maker-flags} or
3561 @code{#:module-build-flags} parameter, respectively.
3563 Which Perl package is used can be specified with @code{#:perl}.
3566 @defvr {Scheme Variable} r-build-system
3567 This variable is exported by @code{(guix build-system r)}. It
3568 implements the build procedure used by @uref{http://r-project.org, R}
3569 packages, which essentially is little more than running @code{R CMD
3570 INSTALL --library=/gnu/store/@dots{}} in an environment where
3571 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3572 are run after installation using the R function
3573 @code{tools::testInstalledPackage}.
3576 @defvr {Scheme Variable} ruby-build-system
3577 This variable is exported by @code{(guix build-system ruby)}. It
3578 implements the RubyGems build procedure used by Ruby packages, which
3579 involves running @code{gem build} followed by @code{gem install}.
3581 The @code{source} field of a package that uses this build system
3582 typically references a gem archive, since this is the format that Ruby
3583 developers use when releasing their software. The build system unpacks
3584 the gem archive, potentially patches the source, runs the test suite,
3585 repackages the gem, and installs it. Additionally, directories and
3586 tarballs may be referenced to allow building unreleased gems from Git or
3587 a traditional source release tarball.
3589 Which Ruby package is used can be specified with the @code{#:ruby}
3590 parameter. A list of additional flags to be passed to the @command{gem}
3591 command can be specified with the @code{#:gem-flags} parameter.
3594 @defvr {Scheme Variable} waf-build-system
3595 This variable is exported by @code{(guix build-system waf)}. It
3596 implements a build procedure around the @code{waf} script. The common
3597 phases---@code{configure}, @code{build}, and @code{install}---are
3598 implemented by passing their names as arguments to the @code{waf}
3601 The @code{waf} script is executed by the Python interpreter. Which
3602 Python package is used to run the script can be specified with the
3603 @code{#:python} parameter.
3606 @defvr {Scheme Variable} haskell-build-system
3607 This variable is exported by @code{(guix build-system haskell)}. It
3608 implements the Cabal build procedure used by Haskell packages, which
3609 involves running @code{runhaskell Setup.hs configure
3610 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3611 Instead of installing the package by running @code{runhaskell Setup.hs
3612 install}, to avoid trying to register libraries in the read-only
3613 compiler store directory, the build system uses @code{runhaskell
3614 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3615 addition, the build system generates the package documentation by
3616 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3617 is passed. Optional Haddock parameters can be passed with the help of
3618 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3619 not found, the build system looks for @code{Setup.lhs} instead.
3621 Which Haskell compiler is used can be specified with the @code{#:haskell}
3622 parameter which defaults to @code{ghc}.
3625 @defvr {Scheme Variable} dub-build-system
3626 This variable is exported by @code{(guix build-system dub)}. It
3627 implements the Dub build procedure used by D packages, which
3628 involves running @code{dub build} and @code{dub run}.
3629 Installation is done by copying the files manually.
3631 Which D compiler is used can be specified with the @code{#:ldc}
3632 parameter which defaults to @code{ldc}.
3635 @defvr {Scheme Variable} emacs-build-system
3636 This variable is exported by @code{(guix build-system emacs)}. It
3637 implements an installation procedure similar to the packaging system
3638 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3640 It first creates the @code{@var{package}-autoloads.el} file, then it
3641 byte compiles all Emacs Lisp files. Differently from the Emacs
3642 packaging system, the Info documentation files are moved to the standard
3643 documentation directory and the @file{dir} file is deleted. Each
3644 package is installed in its own directory under
3645 @file{share/emacs/site-lisp/guix.d}.
3648 @defvr {Scheme Variable} font-build-system
3649 This variable is exported by @code{(guix build-system font)}. It
3650 implements an installation procedure for font packages where upstream
3651 provides pre-compiled TrueType, OpenType, etc. font files that merely
3652 need to be copied into place. It copies font files to standard
3653 locations in the output directory.
3656 Lastly, for packages that do not need anything as sophisticated, a
3657 ``trivial'' build system is provided. It is trivial in the sense that
3658 it provides basically no support: it does not pull any implicit inputs,
3659 and does not have a notion of build phases.
3661 @defvr {Scheme Variable} trivial-build-system
3662 This variable is exported by @code{(guix build-system trivial)}.
3664 This build system requires a @code{#:builder} argument. This argument
3665 must be a Scheme expression that builds the package output(s)---as
3666 with @code{build-expression->derivation} (@pxref{Derivations,
3667 @code{build-expression->derivation}}).
3677 Conceptually, the @dfn{store} is the place where derivations that have
3678 been built successfully are stored---by default, @file{/gnu/store}.
3679 Sub-directories in the store are referred to as @dfn{store items} or
3680 sometimes @dfn{store paths}. The store has an associated database that
3681 contains information such as the store paths referred to by each store
3682 path, and the list of @emph{valid} store items---results of successful
3683 builds. This database resides in @file{@var{localstatedir}/guix/db},
3684 where @var{localstatedir} is the state directory specified @i{via}
3685 @option{--localstatedir} at configure time, usually @file{/var}.
3687 The store is @emph{always} accessed by the daemon on behalf of its clients
3688 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3689 connect to the daemon over a Unix-domain socket, send requests to it,
3690 and read the result---these are remote procedure calls, or RPCs.
3693 Users must @emph{never} modify files under @file{/gnu/store} directly.
3694 This would lead to inconsistencies and break the immutability
3695 assumptions of Guix's functional model (@pxref{Introduction}).
3697 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3698 how to check the integrity of the store and attempt recovery from
3699 accidental modifications.
3702 The @code{(guix store)} module provides procedures to connect to the
3703 daemon, and to perform RPCs. These are described below. By default,
3704 @code{open-connection}, and thus all the @command{guix} commands,
3705 connect to the local daemon or to the URI specified by the
3706 @code{GUIX_DAEMON_SOCKET} environment variable.
3708 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3709 When set, the value of this variable should be a file name or a URI
3710 designating the daemon endpoint. When it is a file name, it denotes a
3711 Unix-domain socket to connect to. In addition to file names, the
3712 supported URI schemes are:
3717 These are for Unix-domain sockets.
3718 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3719 @file{/var/guix/daemon-socket/socket}.
3722 These URIs denote connections over TCP/IP, without encryption nor
3723 authentication of the remote host. The URI must always specify both the
3724 host name and port number:
3727 guix://master.guix.example.org:1234
3730 This setup is suitable on local networks, such as clusters, where only
3731 trusted nodes may connect to the build daemon at
3732 @code{master.guix.example.org}.
3735 @cindex SSH access to build daemons
3736 These URIs allow you to connect to a remote daemon over
3737 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
3738 A typical URL might look like this:
3741 ssh://charlie@@guix.example.org:22
3744 As for @command{guix copy}, the usual OpenSSH client configuration files
3745 are honored (@pxref{Invoking guix copy}).
3748 Additional URI schemes may be supported in the future.
3750 @c XXX: Remove this note when the protocol incurs fewer round trips
3751 @c and when (guix derivations) no longer relies on file system access.
3753 The ability to connect to remote build daemons is considered
3754 experimental as of @value{VERSION}. Please get in touch with us to
3755 share any problems or suggestions you may have (@pxref{Contributing}).
3759 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
3760 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
3761 @var{reserve-space?} is true, instruct it to reserve a little bit of
3762 extra space on the file system so that the garbage collector can still
3763 operate should the disk become full. Return a server object.
3765 @var{file} defaults to @var{%default-socket-path}, which is the normal
3766 location given the options that were passed to @command{configure}.
3769 @deffn {Scheme Procedure} close-connection @var{server}
3770 Close the connection to @var{server}.
3773 @defvr {Scheme Variable} current-build-output-port
3774 This variable is bound to a SRFI-39 parameter, which refers to the port
3775 where build and error logs sent by the daemon should be written.
3778 Procedures that make RPCs all take a server object as their first
3781 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3782 @cindex invalid store items
3783 Return @code{#t} when @var{path} designates a valid store item and
3784 @code{#f} otherwise (an invalid item may exist on disk but still be
3785 invalid, for instance because it is the result of an aborted or failed
3788 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3789 prefixed by the store directory (@file{/gnu/store}).
3792 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3793 Add @var{text} under file @var{name} in the store, and return its store
3794 path. @var{references} is the list of store paths referred to by the
3795 resulting store path.
3798 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3799 Build @var{derivations} (a list of @code{<derivation>} objects or
3800 derivation paths), and return when the worker is done building them.
3801 Return @code{#t} on success.
3804 Note that the @code{(guix monads)} module provides a monad as well as
3805 monadic versions of the above procedures, with the goal of making it
3806 more convenient to work with code that accesses the store (@pxref{The
3810 @i{This section is currently incomplete.}
3813 @section Derivations
3816 Low-level build actions and the environment in which they are performed
3817 are represented by @dfn{derivations}. A derivation contains the
3818 following pieces of information:
3822 The outputs of the derivation---derivations produce at least one file or
3823 directory in the store, but may produce more.
3826 The inputs of the derivations, which may be other derivations or plain
3827 files in the store (patches, build scripts, etc.)
3830 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3833 The file name of a build script in the store, along with the arguments
3837 A list of environment variables to be defined.
3841 @cindex derivation path
3842 Derivations allow clients of the daemon to communicate build actions to
3843 the store. They exist in two forms: as an in-memory representation,
3844 both on the client- and daemon-side, and as files in the store whose
3845 name end in @code{.drv}---these files are referred to as @dfn{derivation
3846 paths}. Derivations paths can be passed to the @code{build-derivations}
3847 procedure to perform the build actions they prescribe (@pxref{The
3850 The @code{(guix derivations)} module provides a representation of
3851 derivations as Scheme objects, along with procedures to create and
3852 otherwise manipulate derivations. The lowest-level primitive to create
3853 a derivation is the @code{derivation} procedure:
3855 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3856 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3857 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3858 [#:system (%current-system)] [#:references-graphs #f] @
3859 [#:allowed-references #f] [#:disallowed-references #f] @
3860 [#:leaked-env-vars #f] [#:local-build? #f] @
3861 [#:substitutable? #t]
3862 Build a derivation with the given arguments, and return the resulting
3863 @code{<derivation>} object.
3865 When @var{hash} and @var{hash-algo} are given, a
3866 @dfn{fixed-output derivation} is created---i.e., one whose result is
3867 known in advance, such as a file download. If, in addition,
3868 @var{recursive?} is true, then that fixed output may be an executable
3869 file or a directory and @var{hash} must be the hash of an archive
3870 containing this output.
3872 When @var{references-graphs} is true, it must be a list of file
3873 name/store path pairs. In that case, the reference graph of each store
3874 path is exported in the build environment in the corresponding file, in
3875 a simple text format.
3877 When @var{allowed-references} is true, it must be a list of store items
3878 or outputs that the derivation's output may refer to. Likewise,
3879 @var{disallowed-references}, if true, must be a list of things the
3880 outputs may @emph{not} refer to.
3882 When @var{leaked-env-vars} is true, it must be a list of strings
3883 denoting environment variables that are allowed to ``leak'' from the
3884 daemon's environment to the build environment. This is only applicable
3885 to fixed-output derivations---i.e., when @var{hash} is true. The main
3886 use is to allow variables such as @code{http_proxy} to be passed to
3887 derivations that download files.
3889 When @var{local-build?} is true, declare that the derivation is not a
3890 good candidate for offloading and should rather be built locally
3891 (@pxref{Daemon Offload Setup}). This is the case for small derivations
3892 where the costs of data transfers would outweigh the benefits.
3894 When @var{substitutable?} is false, declare that substitutes of the
3895 derivation's output should not be used (@pxref{Substitutes}). This is
3896 useful, for instance, when building packages that capture details of the
3897 host CPU instruction set.
3901 Here's an example with a shell script as its builder, assuming
3902 @var{store} is an open connection to the daemon, and @var{bash} points
3903 to a Bash executable in the store:
3906 (use-modules (guix utils)
3910 (let ((builder ; add the Bash script to the store
3911 (add-text-to-store store "my-builder.sh"
3912 "echo hello world > $out\n" '())))
3913 (derivation store "foo"
3914 bash `("-e" ,builder)
3915 #:inputs `((,bash) (,builder))
3916 #:env-vars '(("HOME" . "/homeless"))))
3917 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
3920 As can be guessed, this primitive is cumbersome to use directly. A
3921 better approach is to write build scripts in Scheme, of course! The
3922 best course of action for that is to write the build code as a
3923 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
3924 information, @pxref{G-Expressions}.
3926 Once upon a time, @code{gexp->derivation} did not exist and constructing
3927 derivations with build code written in Scheme was achieved with
3928 @code{build-expression->derivation}, documented below. This procedure
3929 is now deprecated in favor of the much nicer @code{gexp->derivation}.
3931 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
3932 @var{name} @var{exp} @
3933 [#:system (%current-system)] [#:inputs '()] @
3934 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3935 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3936 [#:references-graphs #f] [#:allowed-references #f] @
3937 [#:disallowed-references #f] @
3938 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3939 Return a derivation that executes Scheme expression @var{exp} as a
3940 builder for derivation @var{name}. @var{inputs} must be a list of
3941 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
3942 @code{"out"} is assumed. @var{modules} is a list of names of Guile
3943 modules from the current search path to be copied in the store,
3944 compiled, and made available in the load path during the execution of
3945 @var{exp}---e.g., @code{((guix build utils) (guix build
3946 gnu-build-system))}.
3948 @var{exp} is evaluated in an environment where @code{%outputs} is bound
3949 to a list of output/path pairs, and where @code{%build-inputs} is bound
3950 to a list of string/output-path pairs made from @var{inputs}.
3951 Optionally, @var{env-vars} is a list of string pairs specifying the name
3952 and value of environment variables visible to the builder. The builder
3953 terminates by passing the result of @var{exp} to @code{exit}; thus, when
3954 @var{exp} returns @code{#f}, the build is considered to have failed.
3956 @var{exp} is built using @var{guile-for-build} (a derivation). When
3957 @var{guile-for-build} is omitted or is @code{#f}, the value of the
3958 @code{%guile-for-build} fluid is used instead.
3960 See the @code{derivation} procedure for the meaning of
3961 @var{references-graphs}, @var{allowed-references},
3962 @var{disallowed-references}, @var{local-build?}, and
3963 @var{substitutable?}.
3967 Here's an example of a single-output derivation that creates a directory
3968 containing one file:
3971 (let ((builder '(let ((out (assoc-ref %outputs "out")))
3972 (mkdir out) ; create /gnu/store/@dots{}-goo
3973 (call-with-output-file (string-append out "/test")
3975 (display '(hello guix) p))))))
3976 (build-expression->derivation store "goo" builder))
3978 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
3982 @node The Store Monad
3983 @section The Store Monad
3987 The procedures that operate on the store described in the previous
3988 sections all take an open connection to the build daemon as their first
3989 argument. Although the underlying model is functional, they either have
3990 side effects or depend on the current state of the store.
3992 The former is inconvenient: the connection to the build daemon has to be
3993 carried around in all those functions, making it impossible to compose
3994 functions that do not take that parameter with functions that do. The
3995 latter can be problematic: since store operations have side effects
3996 and/or depend on external state, they have to be properly sequenced.
3998 @cindex monadic values
3999 @cindex monadic functions
4000 This is where the @code{(guix monads)} module comes in. This module
4001 provides a framework for working with @dfn{monads}, and a particularly
4002 useful monad for our uses, the @dfn{store monad}. Monads are a
4003 construct that allows two things: associating ``context'' with values
4004 (in our case, the context is the store), and building sequences of
4005 computations (here computations include accesses to the store). Values
4006 in a monad---values that carry this additional context---are called
4007 @dfn{monadic values}; procedures that return such values are called
4008 @dfn{monadic procedures}.
4010 Consider this ``normal'' procedure:
4013 (define (sh-symlink store)
4014 ;; Return a derivation that symlinks the 'bash' executable.
4015 (let* ((drv (package-derivation store bash))
4016 (out (derivation->output-path drv))
4017 (sh (string-append out "/bin/bash")))
4018 (build-expression->derivation store "sh"
4019 `(symlink ,sh %output))))
4022 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
4023 as a monadic function:
4026 (define (sh-symlink)
4027 ;; Same, but return a monadic value.
4028 (mlet %store-monad ((drv (package->derivation bash)))
4029 (gexp->derivation "sh"
4030 #~(symlink (string-append #$drv "/bin/bash")
4034 There are several things to note in the second version: the @code{store}
4035 parameter is now implicit and is ``threaded'' in the calls to the
4036 @code{package->derivation} and @code{gexp->derivation} monadic
4037 procedures, and the monadic value returned by @code{package->derivation}
4038 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4040 As it turns out, the call to @code{package->derivation} can even be
4041 omitted since it will take place implicitly, as we will see later
4042 (@pxref{G-Expressions}):
4045 (define (sh-symlink)
4046 (gexp->derivation "sh"
4047 #~(symlink (string-append #$bash "/bin/bash")
4052 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4053 @c for the funny quote.
4054 Calling the monadic @code{sh-symlink} has no effect. As someone once
4055 said, ``you exit a monad like you exit a building on fire: by running''.
4056 So, to exit the monad and get the desired effect, one must use
4057 @code{run-with-store}:
4060 (run-with-store (open-connection) (sh-symlink))
4061 @result{} /gnu/store/...-sh-symlink
4064 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4065 new ``meta-commands'' to make it easier to deal with monadic procedures:
4066 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4067 to ``run'' a single monadic value through the store:
4070 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4071 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4074 The latter enters a recursive REPL, where all the return values are
4075 automatically run through the store:
4078 scheme@@(guile-user)> ,enter-store-monad
4079 store-monad@@(guile-user) [1]> (package->derivation hello)
4080 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4081 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4082 $3 = "/gnu/store/@dots{}-foo"
4083 store-monad@@(guile-user) [1]> ,q
4084 scheme@@(guile-user)>
4088 Note that non-monadic values cannot be returned in the
4089 @code{store-monad} REPL.
4091 The main syntactic forms to deal with monads in general are provided by
4092 the @code{(guix monads)} module and are described below.
4094 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4095 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4099 @deffn {Scheme Syntax} return @var{val}
4100 Return a monadic value that encapsulates @var{val}.
4103 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4104 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4105 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4106 referred to as ``bind'', but that name denotes an unrelated procedure in
4107 Guile. Thus we use this somewhat cryptic symbol inherited from the
4108 Haskell language.}. There can be one @var{mproc} or several of them, as
4113 (with-monad %state-monad
4115 (lambda (x) (return (+ 1 x)))
4116 (lambda (x) (return (* 2 x)))))
4120 @result{} some-state
4124 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4126 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4128 Bind the variables @var{var} to the monadic values @var{mval} in
4129 @var{body}, which is a sequence of expressions. As with the bind
4130 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4131 value ``contained'' in @var{mval} and making @var{var} refer to that
4132 raw, non-monadic value within the scope of the @var{body}. The form
4133 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4134 @var{val}, as per @code{let}. The binding operations occur in sequence
4135 from left to right. The last expression of @var{body} must be a monadic
4136 expression, and its result will become the result of the @code{mlet} or
4137 @code{mlet*} when run in the @var{monad}.
4139 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4140 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4143 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4144 Bind @var{mexp} and the following monadic expressions in sequence,
4145 returning the result of the last expression. Every expression in the
4146 sequence must be a monadic expression.
4148 This is akin to @code{mlet}, except that the return values of the
4149 monadic expressions are ignored. In that sense, it is analogous to
4150 @code{begin}, but applied to monadic expressions.
4153 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4154 When @var{condition} is true, evaluate the sequence of monadic
4155 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4156 @var{condition} is false, return @code{*unspecified*} in the current
4157 monad. Every expression in the sequence must be a monadic expression.
4160 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4161 When @var{condition} is false, evaluate the sequence of monadic
4162 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4163 @var{condition} is true, return @code{*unspecified*} in the current
4164 monad. Every expression in the sequence must be a monadic expression.
4168 The @code{(guix monads)} module provides the @dfn{state monad}, which
4169 allows an additional value---the state---to be @emph{threaded} through
4170 monadic procedure calls.
4172 @defvr {Scheme Variable} %state-monad
4173 The state monad. Procedures in the state monad can access and change
4174 the state that is threaded.
4176 Consider the example below. The @code{square} procedure returns a value
4177 in the state monad. It returns the square of its argument, but also
4178 increments the current state value:
4182 (mlet %state-monad ((count (current-state)))
4183 (mbegin %state-monad
4184 (set-current-state (+ 1 count))
4187 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4192 When ``run'' through @var{%state-monad}, we obtain that additional state
4193 value, which is the number of @code{square} calls.
4196 @deffn {Monadic Procedure} current-state
4197 Return the current state as a monadic value.
4200 @deffn {Monadic Procedure} set-current-state @var{value}
4201 Set the current state to @var{value} and return the previous state as a
4205 @deffn {Monadic Procedure} state-push @var{value}
4206 Push @var{value} to the current state, which is assumed to be a list,
4207 and return the previous state as a monadic value.
4210 @deffn {Monadic Procedure} state-pop
4211 Pop a value from the current state and return it as a monadic value.
4212 The state is assumed to be a list.
4215 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4216 Run monadic value @var{mval} starting with @var{state} as the initial
4217 state. Return two values: the resulting value, and the resulting state.
4220 The main interface to the store monad, provided by the @code{(guix
4221 store)} module, is as follows.
4223 @defvr {Scheme Variable} %store-monad
4224 The store monad---an alias for @var{%state-monad}.
4226 Values in the store monad encapsulate accesses to the store. When its
4227 effect is needed, a value of the store monad must be ``evaluated'' by
4228 passing it to the @code{run-with-store} procedure (see below.)
4231 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4232 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4233 open store connection.
4236 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4237 Return as a monadic value the absolute file name in the store of the file
4238 containing @var{text}, a string. @var{references} is a list of store items that the
4239 resulting text file refers to; it defaults to the empty list.
4242 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4243 [#:recursive? #t] [#:select? (const #t)]
4244 Return the name of @var{file} once interned in the store. Use
4245 @var{name} as its store name, or the basename of @var{file} if
4246 @var{name} is omitted.
4248 When @var{recursive?} is true, the contents of @var{file} are added
4249 recursively; if @var{file} designates a flat file and @var{recursive?}
4250 is true, its contents are added, and its permission bits are kept.
4252 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4253 @var{stat})} for each directory entry, where @var{file} is the entry's
4254 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4255 entries for which @var{select?} does not return true.
4257 The example below adds a file to the store, under two different names:
4260 (run-with-store (open-connection)
4261 (mlet %store-monad ((a (interned-file "README"))
4262 (b (interned-file "README" "LEGU-MIN")))
4263 (return (list a b))))
4265 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4270 The @code{(guix packages)} module exports the following package-related
4273 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4274 [#:system (%current-system)] [#:target #f] @
4277 value in the absolute file name of @var{file} within the @var{output}
4278 directory of @var{package}. When @var{file} is omitted, return the name
4279 of the @var{output} directory of @var{package}. When @var{target} is
4280 true, use it as a cross-compilation target triplet.
4283 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4284 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4285 @var{target} [@var{system}]
4286 Monadic version of @code{package-derivation} and
4287 @code{package-cross-derivation} (@pxref{Defining Packages}).
4292 @section G-Expressions
4294 @cindex G-expression
4295 @cindex build code quoting
4296 So we have ``derivations'', which represent a sequence of build actions
4297 to be performed to produce an item in the store (@pxref{Derivations}).
4298 These build actions are performed when asking the daemon to actually
4299 build the derivations; they are run by the daemon in a container
4300 (@pxref{Invoking guix-daemon}).
4302 @cindex strata of code
4303 It should come as no surprise that we like to write these build actions
4304 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4305 code@footnote{The term @dfn{stratum} in this context was coined by
4306 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4307 Kiselyov, who has written insightful
4308 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4309 on this topic}, refers to this kind of code generation as
4310 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4311 to the daemon, etc.---and the ``build code''---code that actually
4312 performs build actions, such as making directories, invoking
4313 @command{make}, etc.
4315 To describe a derivation and its build actions, one typically needs to
4316 embed build code inside host code. It boils down to manipulating build
4317 code as data, and the homoiconicity of Scheme---code has a direct
4318 representation as data---comes in handy for that. But we need more than
4319 the normal @code{quasiquote} mechanism in Scheme to construct build
4322 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4323 S-expressions adapted to build expressions. G-expressions, or
4324 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4325 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4326 @code{#$}, and @code{#$@@}), which are comparable to
4327 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4328 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4329 GNU Guile Reference Manual}). However, there are major differences:
4333 Gexps are meant to be written to a file and run or manipulated by other
4337 When a high-level object such as a package or derivation is unquoted
4338 inside a gexp, the result is as if its output file name had been
4342 Gexps carry information about the packages or derivations they refer to,
4343 and these dependencies are automatically added as inputs to the build
4344 processes that use them.
4347 @cindex lowering, of high-level objects in gexps
4348 This mechanism is not limited to package and derivation
4349 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4350 derivations or files in the store can be defined,
4351 such that these objects can also be inserted
4352 into gexps. For example, a useful type of high-level objects that can be
4353 inserted in a gexp is ``file-like objects'', which make it easy to
4354 add files to the store and to refer to them in
4355 derivations and such (see @code{local-file} and @code{plain-file}
4358 To illustrate the idea, here is an example of a gexp:
4365 (symlink (string-append #$coreutils "/bin/ls")
4369 This gexp can be passed to @code{gexp->derivation}; we obtain a
4370 derivation that builds a directory containing exactly one symlink to
4371 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4374 (gexp->derivation "the-thing" build-exp)
4377 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4378 substituted to the reference to the @var{coreutils} package in the
4379 actual build code, and @var{coreutils} is automatically made an input to
4380 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4381 output)}) is replaced by a string containing the directory name of the
4382 output of the derivation.
4384 @cindex cross compilation
4385 In a cross-compilation context, it is useful to distinguish between
4386 references to the @emph{native} build of a package---that can run on the
4387 host---versus references to cross builds of a package. To that end, the
4388 @code{#+} plays the same role as @code{#$}, but is a reference to a
4389 native package build:
4392 (gexp->derivation "vi"
4395 (system* (string-append #+coreutils "/bin/ln")
4397 (string-append #$emacs "/bin/emacs")
4398 (string-append #$output "/bin/vi")))
4399 #:target "mips64el-linux-gnu")
4403 In the example above, the native build of @var{coreutils} is used, so
4404 that @command{ln} can actually run on the host; but then the
4405 cross-compiled build of @var{emacs} is referenced.
4407 @cindex imported modules, for gexps
4408 @findex with-imported-modules
4409 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4410 able to use certain Guile modules from the ``host environment'' in the
4411 gexp, so those modules should be imported in the ``build environment''.
4412 The @code{with-imported-modules} form allows you to express that:
4415 (let ((build (with-imported-modules '((guix build utils))
4417 (use-modules (guix build utils))
4418 (mkdir-p (string-append #$output "/bin"))))))
4419 (gexp->derivation "empty-dir"
4422 (display "success!\n")
4427 In this example, the @code{(guix build utils)} module is automatically
4428 pulled into the isolated build environment of our gexp, such that
4429 @code{(use-modules (guix build utils))} works as expected.
4431 @cindex module closure
4432 @findex source-module-closure
4433 Usually you want the @emph{closure} of the module to be imported---i.e.,
4434 the module itself and all the modules it depends on---rather than just
4435 the module; failing to do that, attempts to use the module will fail
4436 because of missing dependent modules. The @code{source-module-closure}
4437 procedure computes the closure of a module by looking at its source file
4438 headers, which comes in handy in this case:
4441 (use-modules (guix modules)) ;for 'source-module-closure'
4443 (with-imported-modules (source-module-closure
4444 '((guix build utils)
4446 (gexp->derivation "something-with-vms"
4448 (use-modules (guix build utils)
4453 The syntactic form to construct gexps is summarized below.
4455 @deffn {Scheme Syntax} #~@var{exp}
4456 @deffnx {Scheme Syntax} (gexp @var{exp})
4457 Return a G-expression containing @var{exp}. @var{exp} may contain one
4458 or more of the following forms:
4462 @itemx (ungexp @var{obj})
4463 Introduce a reference to @var{obj}. @var{obj} may have one of the
4464 supported types, for example a package or a
4465 derivation, in which case the @code{ungexp} form is replaced by its
4466 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4468 If @var{obj} is a list, it is traversed and references to supported
4469 objects are substituted similarly.
4471 If @var{obj} is another gexp, its contents are inserted and its
4472 dependencies are added to those of the containing gexp.
4474 If @var{obj} is another kind of object, it is inserted as is.
4476 @item #$@var{obj}:@var{output}
4477 @itemx (ungexp @var{obj} @var{output})
4478 This is like the form above, but referring explicitly to the
4479 @var{output} of @var{obj}---this is useful when @var{obj} produces
4480 multiple outputs (@pxref{Packages with Multiple Outputs}).
4483 @itemx #+@var{obj}:output
4484 @itemx (ungexp-native @var{obj})
4485 @itemx (ungexp-native @var{obj} @var{output})
4486 Same as @code{ungexp}, but produces a reference to the @emph{native}
4487 build of @var{obj} when used in a cross compilation context.
4489 @item #$output[:@var{output}]
4490 @itemx (ungexp output [@var{output}])
4491 Insert a reference to derivation output @var{output}, or to the main
4492 output when @var{output} is omitted.
4494 This only makes sense for gexps passed to @code{gexp->derivation}.
4497 @itemx (ungexp-splicing @var{lst})
4498 Like the above, but splices the contents of @var{lst} inside the
4502 @itemx (ungexp-native-splicing @var{lst})
4503 Like the above, but refers to native builds of the objects listed in
4508 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4509 of the @code{gexp?} type (see below.)
4512 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4513 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4514 in their execution environment.
4516 Each item in @var{modules} can be the name of a module, such as
4517 @code{(guix build utils)}, or it can be a module name, followed by an
4518 arrow, followed by a file-like object:
4521 `((guix build utils)
4523 ((guix config) => ,(scheme-file "config.scm"
4524 #~(define-module @dots{}))))
4528 In the example above, the first two modules are taken from the search
4529 path, and the last one is created from the given file-like object.
4531 This form has @emph{lexical} scope: it has an effect on the gexps
4532 directly defined in @var{body}@dots{}, but not on those defined, say, in
4533 procedures called from @var{body}@dots{}.
4536 @deffn {Scheme Procedure} gexp? @var{obj}
4537 Return @code{#t} if @var{obj} is a G-expression.
4540 G-expressions are meant to be written to disk, either as code building
4541 some derivation, or as plain files in the store. The monadic procedures
4542 below allow you to do that (@pxref{The Store Monad}, for more
4543 information about monads.)
4545 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4546 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4547 [#:hash #f] [#:hash-algo #f] @
4548 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4549 [#:module-path @var{%load-path}] @
4550 [#:references-graphs #f] [#:allowed-references #f] @
4551 [#:disallowed-references #f] @
4552 [#:leaked-env-vars #f] @
4553 [#:script-name (string-append @var{name} "-builder")] @
4554 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4555 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4556 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4557 stored in a file called @var{script-name}. When @var{target} is true,
4558 it is used as the cross-compilation target triplet for packages referred
4561 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4563 make @var{modules} available in the evaluation context of @var{exp};
4564 @var{modules} is a list of names of Guile modules searched in
4565 @var{module-path} to be copied in the store, compiled, and made available in
4566 the load path during the execution of @var{exp}---e.g., @code{((guix
4567 build utils) (guix build gnu-build-system))}.
4569 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4572 When @var{references-graphs} is true, it must be a list of tuples of one of the
4576 (@var{file-name} @var{package})
4577 (@var{file-name} @var{package} @var{output})
4578 (@var{file-name} @var{derivation})
4579 (@var{file-name} @var{derivation} @var{output})
4580 (@var{file-name} @var{store-item})
4583 The right-hand-side of each element of @var{references-graphs} is automatically made
4584 an input of the build process of @var{exp}. In the build environment, each
4585 @var{file-name} contains the reference graph of the corresponding item, in a simple
4588 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4589 In the latter case, the list denotes store items that the result is allowed to
4590 refer to. Any reference to another store item will lead to a build error.
4591 Similarly for @var{disallowed-references}, which can list items that must not be
4592 referenced by the outputs.
4594 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4597 @cindex file-like objects
4598 The @code{local-file}, @code{plain-file}, @code{computed-file},
4599 @code{program-file}, and @code{scheme-file} procedures below return
4600 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4601 these objects lead to a file in the store. Consider this G-expression:
4604 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4605 #$(local-file "/tmp/my-nscd.conf"))
4608 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4609 to the store. Once expanded, for instance @i{via}
4610 @code{gexp->derivation}, the G-expression refers to that copy under
4611 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4612 does not have any effect on what the G-expression does.
4613 @code{plain-file} can be used similarly; it differs in that the file
4614 content is directly passed as a string.
4616 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4617 [#:recursive? #f] [#:select? (const #t)]
4618 Return an object representing local file @var{file} to add to the store; this
4619 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4620 up relative to the source file where this form appears. @var{file} will be added to
4621 the store under @var{name}--by default the base name of @var{file}.
4623 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4624 designates a flat file and @var{recursive?} is true, its contents are added, and its
4625 permission bits are kept.
4627 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4628 @var{stat})} for each directory entry, where @var{file} is the entry's
4629 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4630 entries for which @var{select?} does not return true.
4632 This is the declarative counterpart of the @code{interned-file} monadic
4633 procedure (@pxref{The Store Monad, @code{interned-file}}).
4636 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4637 Return an object representing a text file called @var{name} with the given
4638 @var{content} (a string) to be added to the store.
4640 This is the declarative counterpart of @code{text-file}.
4643 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4644 [#:options '(#:local-build? #t)]
4645 Return an object representing the store item @var{name}, a file or
4646 directory computed by @var{gexp}. @var{options}
4647 is a list of additional arguments to pass to @code{gexp->derivation}.
4649 This is the declarative counterpart of @code{gexp->derivation}.
4652 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4653 Return an executable script @var{name} that runs @var{exp} using
4654 @var{guile}, with @var{exp}'s imported modules in its search path.
4656 The example below builds a script that simply invokes the @command{ls}
4660 (use-modules (guix gexp) (gnu packages base))
4662 (gexp->script "list-files"
4663 #~(execl #$(file-append coreutils "/bin/ls")
4667 When ``running'' it through the store (@pxref{The Store Monad,
4668 @code{run-with-store}}), we obtain a derivation that produces an
4669 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4672 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4674 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4678 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4680 Return an object representing the executable store item @var{name} that
4681 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4684 This is the declarative counterpart of @code{gexp->script}.
4687 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4688 [#:set-load-path? #t]
4689 Return a derivation that builds a file @var{name} containing @var{exp}.
4690 When @var{set-load-path?} is true, emit code in the resulting file to
4691 set @code{%load-path} and @code{%load-compiled-path} to honor
4692 @var{exp}'s imported modules.
4694 The resulting file holds references to all the dependencies of @var{exp}
4695 or a subset thereof.
4698 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4699 Return an object representing the Scheme file @var{name} that contains
4702 This is the declarative counterpart of @code{gexp->file}.
4705 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4706 Return as a monadic value a derivation that builds a text file
4707 containing all of @var{text}. @var{text} may list, in addition to
4708 strings, objects of any type that can be used in a gexp: packages,
4709 derivations, local file objects, etc. The resulting store file holds
4710 references to all these.
4712 This variant should be preferred over @code{text-file} anytime the file
4713 to create will reference items from the store. This is typically the
4714 case when building a configuration file that embeds store file names,
4718 (define (profile.sh)
4719 ;; Return the name of a shell script in the store that
4720 ;; initializes the 'PATH' environment variable.
4721 (text-file* "profile.sh"
4722 "export PATH=" coreutils "/bin:"
4723 grep "/bin:" sed "/bin\n"))
4726 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4727 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4728 preventing them from being garbage-collected during its lifetime.
4731 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4732 Return an object representing store file @var{name} containing
4733 @var{text}. @var{text} is a sequence of strings and file-like objects,
4737 (mixed-text-file "profile"
4738 "export PATH=" coreutils "/bin:" grep "/bin")
4741 This is the declarative counterpart of @code{text-file*}.
4744 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4745 Return a file-like object that expands to the concatenation of @var{obj}
4746 and @var{suffix}, where @var{obj} is a lowerable object and each
4747 @var{suffix} is a string.
4749 As an example, consider this gexp:
4752 (gexp->script "run-uname"
4753 #~(system* #$(file-append coreutils
4757 The same effect could be achieved with:
4760 (gexp->script "run-uname"
4761 #~(system* (string-append #$coreutils
4765 There is one difference though: in the @code{file-append} case, the
4766 resulting script contains the absolute file name as a string, whereas in
4767 the second case, the resulting script contains a @code{(string-append
4768 @dots{})} expression to construct the file name @emph{at run time}.
4772 Of course, in addition to gexps embedded in ``host'' code, there are
4773 also modules containing build tools. To make it clear that they are
4774 meant to be used in the build stratum, these modules are kept in the
4775 @code{(guix build @dots{})} name space.
4777 @cindex lowering, of high-level objects in gexps
4778 Internally, high-level objects are @dfn{lowered}, using their compiler,
4779 to either derivations or store items. For instance, lowering a package
4780 yields a derivation, and lowering a @code{plain-file} yields a store
4781 item. This is achieved using the @code{lower-object} monadic procedure.
4783 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4785 Return as a value in @var{%store-monad} the derivation or store item
4786 corresponding to @var{obj} for @var{system}, cross-compiling for
4787 @var{target} if @var{target} is true. @var{obj} must be an object that
4788 has an associated gexp compiler, such as a @code{<package>}.
4792 @c *********************************************************************
4796 This section describes Guix command-line utilities. Some of them are
4797 primarily targeted at developers and users who write new package
4798 definitions, while others are more generally useful. They complement
4799 the Scheme programming interface of Guix in a convenient way.
4802 * Invoking guix build:: Building packages from the command line.
4803 * Invoking guix edit:: Editing package definitions.
4804 * Invoking guix download:: Downloading a file and printing its hash.
4805 * Invoking guix hash:: Computing the cryptographic hash of a file.
4806 * Invoking guix import:: Importing package definitions.
4807 * Invoking guix refresh:: Updating package definitions.
4808 * Invoking guix lint:: Finding errors in package definitions.
4809 * Invoking guix size:: Profiling disk usage.
4810 * Invoking guix graph:: Visualizing the graph of packages.
4811 * Invoking guix environment:: Setting up development environments.
4812 * Invoking guix publish:: Sharing substitutes.
4813 * Invoking guix challenge:: Challenging substitute servers.
4814 * Invoking guix copy:: Copying to and from a remote store.
4815 * Invoking guix container:: Process isolation.
4818 @node Invoking guix build
4819 @section Invoking @command{guix build}
4821 @cindex package building
4822 @cindex @command{guix build}
4823 The @command{guix build} command builds packages or derivations and
4824 their dependencies, and prints the resulting store paths. Note that it
4825 does not modify the user's profile---this is the job of the
4826 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4827 it is mainly useful for distribution developers.
4829 The general syntax is:
4832 guix build @var{options} @var{package-or-derivation}@dots{}
4835 As an example, the following command builds the latest versions of Emacs
4836 and of Guile, displays their build logs, and finally displays the
4837 resulting directories:
4840 guix build emacs guile
4843 Similarly, the following command builds all the available packages:
4846 guix build --quiet --keep-going \
4847 `guix package -A | cut -f1,2 --output-delimiter=@@`
4850 @var{package-or-derivation} may be either the name of a package found in
4851 the software distribution such as @code{coreutils} or
4852 @code{coreutils@@8.20}, or a derivation such as
4853 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4854 package with the corresponding name (and optionally version) is searched
4855 for among the GNU distribution modules (@pxref{Package Modules}).
4857 Alternatively, the @code{--expression} option may be used to specify a
4858 Scheme expression that evaluates to a package; this is useful when
4859 disambiguating among several same-named packages or package variants is
4862 There may be zero or more @var{options}. The available options are
4863 described in the subsections below.
4866 * Common Build Options:: Build options for most commands.
4867 * Package Transformation Options:: Creating variants of packages.
4868 * Additional Build Options:: Options specific to 'guix build'.
4869 * Debugging Build Failures:: Real life packaging experience
4872 @node Common Build Options
4873 @subsection Common Build Options
4875 A number of options that control the build process are common to
4876 @command{guix build} and other commands that can spawn builds, such as
4877 @command{guix package} or @command{guix archive}. These are the
4882 @item --load-path=@var{directory}
4883 @itemx -L @var{directory}
4884 Add @var{directory} to the front of the package module search path
4885 (@pxref{Package Modules}).
4887 This allows users to define their own packages and make them visible to
4888 the command-line tools.
4892 Keep the build tree of failed builds. Thus, if a build fails, its build
4893 tree is kept under @file{/tmp}, in a directory whose name is shown at
4894 the end of the build log. This is useful when debugging build issues.
4895 @xref{Debugging Build Failures}, for tips and tricks on how to debug
4900 Keep going when some of the derivations fail to build; return only once
4901 all the builds have either completed or failed.
4903 The default behavior is to stop as soon as one of the specified
4904 derivations has failed.
4908 Do not build the derivations.
4911 When substituting a pre-built binary fails, fall back to building
4914 @item --substitute-urls=@var{urls}
4915 @anchor{client-substitute-urls}
4916 Consider @var{urls} the whitespace-separated list of substitute source
4917 URLs, overriding the default list of URLs of @command{guix-daemon}
4918 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
4920 This means that substitutes may be downloaded from @var{urls}, provided
4921 they are signed by a key authorized by the system administrator
4922 (@pxref{Substitutes}).
4924 When @var{urls} is the empty string, substitutes are effectively
4927 @item --no-substitutes
4928 Do not use substitutes for build products. That is, always build things
4929 locally instead of allowing downloads of pre-built binaries
4930 (@pxref{Substitutes}).
4933 Do not ``graft'' packages. In practice, this means that package updates
4934 available as grafts are not applied. @xref{Security Updates}, for more
4935 information on grafts.
4937 @item --rounds=@var{n}
4938 Build each derivation @var{n} times in a row, and raise an error if
4939 consecutive build results are not bit-for-bit identical.
4941 This is a useful way to detect non-deterministic builds processes.
4942 Non-deterministic build processes are a problem because they make it
4943 practically impossible for users to @emph{verify} whether third-party
4944 binaries are genuine. @xref{Invoking guix challenge}, for more.
4946 Note that, currently, the differing build results are not kept around,
4947 so you will have to manually investigate in case of an error---e.g., by
4948 stashing one of the build results with @code{guix archive --export}
4949 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
4952 @item --no-build-hook
4953 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
4954 (@pxref{Daemon Offload Setup}). That is, always build things locally
4955 instead of offloading builds to remote machines.
4957 @item --max-silent-time=@var{seconds}
4958 When the build or substitution process remains silent for more than
4959 @var{seconds}, terminate it and report a build failure.
4961 By default, the daemon's setting is honored (@pxref{Invoking
4962 guix-daemon, @code{--max-silent-time}}).
4964 @item --timeout=@var{seconds}
4965 Likewise, when the build or substitution process lasts for more than
4966 @var{seconds}, terminate it and report a build failure.
4968 By default, the daemon's setting is honored (@pxref{Invoking
4969 guix-daemon, @code{--timeout}}).
4971 @item --verbosity=@var{level}
4972 Use the given verbosity level. @var{level} must be an integer between 0
4973 and 5; higher means more verbose output. Setting a level of 4 or more
4974 may be helpful when debugging setup issues with the build daemon.
4976 @item --cores=@var{n}
4978 Allow the use of up to @var{n} CPU cores for the build. The special
4979 value @code{0} means to use as many CPU cores as available.
4981 @item --max-jobs=@var{n}
4983 Allow at most @var{n} build jobs in parallel. @xref{Invoking
4984 guix-daemon, @code{--max-jobs}}, for details about this option and the
4985 equivalent @command{guix-daemon} option.
4989 Behind the scenes, @command{guix build} is essentially an interface to
4990 the @code{package-derivation} procedure of the @code{(guix packages)}
4991 module, and to the @code{build-derivations} procedure of the @code{(guix
4992 derivations)} module.
4994 In addition to options explicitly passed on the command line,
4995 @command{guix build} and other @command{guix} commands that support
4996 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
4998 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
4999 Users can define this variable to a list of command line options that
5000 will automatically be used by @command{guix build} and other
5001 @command{guix} commands that can perform builds, as in the example
5005 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
5008 These options are parsed independently, and the result is appended to
5009 the parsed command-line options.
5013 @node Package Transformation Options
5014 @subsection Package Transformation Options
5016 @cindex package variants
5017 Another set of command-line options supported by @command{guix build}
5018 and also @command{guix package} are @dfn{package transformation
5019 options}. These are options that make it possible to define @dfn{package
5020 variants}---for instance, packages built from different source code.
5021 This is a convenient way to create customized packages on the fly
5022 without having to type in the definitions of package variants
5023 (@pxref{Defining Packages}).
5027 @item --with-source=@var{source}
5028 Use @var{source} as the source of the corresponding package.
5029 @var{source} must be a file name or a URL, as for @command{guix
5030 download} (@pxref{Invoking guix download}).
5032 The ``corresponding package'' is taken to be the one specified on the
5033 command line the name of which matches the base of @var{source}---e.g.,
5034 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
5035 package is @code{guile}. Likewise, the version string is inferred from
5036 @var{source}; in the previous example, it is @code{2.0.10}.
5038 This option allows users to try out versions of packages other than the
5039 one provided by the distribution. The example below downloads
5040 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5041 the @code{ed} package:
5044 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5047 As a developer, @code{--with-source} makes it easy to test release
5051 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5054 @dots{} or to build from a checkout in a pristine environment:
5057 $ git clone git://git.sv.gnu.org/guix.git
5058 $ guix build guix --with-source=./guix
5061 @item --with-input=@var{package}=@var{replacement}
5062 Replace dependency on @var{package} by a dependency on
5063 @var{replacement}. @var{package} must be a package name, and
5064 @var{replacement} must be a package specification such as @code{guile}
5065 or @code{guile@@1.8}.
5067 For instance, the following command builds Guix, but replaces its
5068 dependency on the current stable version of Guile with a dependency on
5069 the legacy version of Guile, @code{guile@@2.0}:
5072 guix build --with-input=guile=guile@@2.0 guix
5075 This is a recursive, deep replacement. So in this example, both
5076 @code{guix} and its dependency @code{guile-json} (which also depends on
5077 @code{guile}) get rebuilt against @code{guile@@2.0}.
5079 This is implemented using the @code{package-input-rewriting} Scheme
5080 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5082 @item --with-graft=@var{package}=@var{replacement}
5083 This is similar to @code{--with-input} but with an important difference:
5084 instead of rebuilding the whole dependency chain, @var{replacement} is
5085 built and then @dfn{grafted} onto the binaries that were initially
5086 referring to @var{package}. @xref{Security Updates}, for more
5087 information on grafts.
5089 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5090 and all its dependencies, replacing references to the version of GnuTLS
5091 they currently refer to:
5094 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5097 This has the advantage of being much faster than rebuilding everything.
5098 But there is a caveat: it works if and only if @var{package} and
5099 @var{replacement} are strictly compatible---for example, if they provide
5100 a library, the application binary interface (ABI) of those libraries
5101 must be compatible. If @var{replacement} is somehow incompatible with
5102 @var{package}, then the resulting package may be unusable. Use with
5107 @node Additional Build Options
5108 @subsection Additional Build Options
5110 The command-line options presented below are specific to @command{guix
5117 Build quietly, without displaying the build log. Upon completion, the
5118 build log is kept in @file{/var} (or similar) and can always be
5119 retrieved using the @option{--log-file} option.
5121 @item --file=@var{file}
5122 @itemx -f @var{file}
5124 Build the package or derivation that the code within @var{file}
5127 As an example, @var{file} might contain a package definition like this
5128 (@pxref{Defining Packages}):
5131 @verbatiminclude package-hello.scm
5134 @item --expression=@var{expr}
5135 @itemx -e @var{expr}
5136 Build the package or derivation @var{expr} evaluates to.
5138 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5139 guile-1.8)}, which unambiguously designates this specific variant of
5140 version 1.8 of Guile.
5142 Alternatively, @var{expr} may be a G-expression, in which case it is used
5143 as a build program passed to @code{gexp->derivation}
5144 (@pxref{G-Expressions}).
5146 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5147 (@pxref{The Store Monad}). The procedure must return a derivation as a
5148 monadic value, which is then passed through @code{run-with-store}.
5152 Build the source derivations of the packages, rather than the packages
5155 For instance, @code{guix build -S gcc} returns something like
5156 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5159 The returned source tarball is the result of applying any patches and
5160 code snippets specified in the package @code{origin} (@pxref{Defining
5164 Fetch and return the source of @var{package-or-derivation} and all their
5165 dependencies, recursively. This is a handy way to obtain a local copy
5166 of all the source code needed to build @var{packages}, allowing you to
5167 eventually build them even without network access. It is an extension
5168 of the @code{--source} option and can accept one of the following
5169 optional argument values:
5173 This value causes the @code{--sources} option to behave in the same way
5174 as the @code{--source} option.
5177 Build the source derivations of all packages, including any source that
5178 might be listed as @code{inputs}. This is the default value.
5181 $ guix build --sources tzdata
5182 The following derivations will be built:
5183 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5184 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5188 Build the source derivations of all packages, as well of all transitive
5189 inputs to the packages. This can be used e.g. to
5190 prefetch package source for later offline building.
5193 $ guix build --sources=transitive tzdata
5194 The following derivations will be built:
5195 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5196 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5197 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5198 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5199 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5200 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5206 @item --system=@var{system}
5207 @itemx -s @var{system}
5208 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5209 the system type of the build host.
5211 An example use of this is on Linux-based systems, which can emulate
5212 different personalities. For instance, passing
5213 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5214 to build packages in a complete 32-bit environment.
5216 @item --target=@var{triplet}
5217 @cindex cross-compilation
5218 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5219 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5220 configuration triplets,, autoconf, Autoconf}).
5222 @anchor{build-check}
5224 @cindex determinism, checking
5225 @cindex reproducibility, checking
5226 Rebuild @var{package-or-derivation}, which are already available in the
5227 store, and raise an error if the build results are not bit-for-bit
5230 This mechanism allows you to check whether previously installed
5231 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5232 of a package is deterministic. @xref{Invoking guix challenge}, for more
5233 background information and tools.
5235 When used in conjunction with @option{--keep-failed}, the differing
5236 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5237 This makes it easy to look for differences between the two results.
5240 @cindex repairing store items
5241 @cindex corruption, recovering from
5242 Attempt to repair the specified store items, if they are corrupt, by
5243 re-downloading or rebuilding them.
5245 This operation is not atomic and thus restricted to @code{root}.
5249 Return the derivation paths, not the output paths, of the given
5252 @item --root=@var{file}
5253 @itemx -r @var{file}
5254 Make @var{file} a symlink to the result, and register it as a garbage
5258 Return the build log file names or URLs for the given
5259 @var{package-or-derivation}, or raise an error if build logs are
5262 This works regardless of how packages or derivations are specified. For
5263 instance, the following invocations are equivalent:
5266 guix build --log-file `guix build -d guile`
5267 guix build --log-file `guix build guile`
5268 guix build --log-file guile
5269 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5272 If a log is unavailable locally, and unless @code{--no-substitutes} is
5273 passed, the command looks for a corresponding log on one of the
5274 substitute servers (as specified with @code{--substitute-urls}.)
5276 So for instance, imagine you want to see the build log of GDB on MIPS,
5277 but you are actually on an @code{x86_64} machine:
5280 $ guix build --log-file gdb -s mips64el-linux
5281 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5284 You can freely access a huge library of build logs!
5287 @node Debugging Build Failures
5288 @subsection Debugging Build Failures
5290 @cindex build failures, debugging
5291 When defining a new package (@pxref{Defining Packages}), you will
5292 probably find yourself spending some time debugging and tweaking the
5293 build until it succeeds. To do that, you need to operate the build
5294 commands yourself in an environment as close as possible to the one the
5297 To that end, the first thing to do is to use the @option{--keep-failed}
5298 or @option{-K} option of @command{guix build}, which will keep the
5299 failed build tree in @file{/tmp} or whatever directory you specified as
5300 @code{TMPDIR} (@pxref{Invoking guix build, @code{--keep-failed}}).
5302 From there on, you can @command{cd} to the failed build tree and source
5303 the @file{environment-variables} file, which contains all the
5304 environment variable definitions that were in place when the build
5305 failed. So let's say you're debugging a build failure in package
5306 @code{foo}; a typical session would look like this:
5310 @dots{} @i{build fails}
5311 $ cd /tmp/guix-build-foo.drv-0
5312 $ source ./environment-variables
5316 Now, you can invoke commands as if you were the daemon (almost) and
5317 troubleshoot your build process.
5319 Sometimes it happens that, for example, a package's tests pass when you
5320 run them manually but they fail when the daemon runs them. This can
5321 happen because the daemon runs builds in containers where, unlike in our
5322 environment above, network access is missing, @file{/bin/sh} does not
5323 exist, etc. (@pxref{Build Environment Setup}).
5325 In such cases, you may need to run inspect the build process from within
5326 a container similar to the one the build daemon creates:
5331 $ cd /tmp/guix-build-foo.drv-0
5332 $ guix environment --no-grafts -C foo --ad-hoc strace gdb
5333 [env]# source ./environment-variables
5337 Here, @command{guix environment -C} creates a container and spawns a new
5338 shell in it (@pxref{Invoking guix environment}). The @command{--ad-hoc
5339 strace gdb} part adds the @command{strace} and @command{gdb} commands to
5340 the container, which would may find handy while debugging. The
5341 @option{--no-grafts} option makes sure we get the exact same
5342 environment, with ungrafted packages (@pxref{Security Updates}, for more
5345 To get closer to a container like that used by the build daemon, we can
5346 remove @file{/bin/sh}:
5352 (Don't worry, this is harmless: this is all happening in the throw-away
5353 container created by @command{guix environment}.)
5355 The @command{strace} command is probably not in the search path, but we
5359 [env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check
5362 In this way, not only you will have reproduced the environment variables
5363 the daemon uses, you will also be running the build process in a container
5364 similar to the one the daemon uses.
5367 @node Invoking guix edit
5368 @section Invoking @command{guix edit}
5370 @cindex @command{guix edit}
5371 @cindex package definition, editing
5372 So many packages, so many source files! The @command{guix edit} command
5373 facilitates the life of users and packagers by pointing their editor at
5374 the source file containing the definition of the specified packages.
5378 guix edit gcc@@4.9 vim
5382 launches the program specified in the @code{VISUAL} or in the
5383 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5386 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5387 have created your own packages on @code{GUIX_PACKAGE_PATH}
5388 (@pxref{Defining Packages}), you will be able to edit the package
5389 recipes. Otherwise, you will be able to examine the read-only recipes
5390 for packages currently in the store.
5393 @node Invoking guix download
5394 @section Invoking @command{guix download}
5396 @cindex @command{guix download}
5397 @cindex downloading package sources
5398 When writing a package definition, developers typically need to download
5399 a source tarball, compute its SHA256 hash, and write that
5400 hash in the package definition (@pxref{Defining Packages}). The
5401 @command{guix download} tool helps with this task: it downloads a file
5402 from the given URI, adds it to the store, and prints both its file name
5403 in the store and its SHA256 hash.
5405 The fact that the downloaded file is added to the store saves bandwidth:
5406 when the developer eventually tries to build the newly defined package
5407 with @command{guix build}, the source tarball will not have to be
5408 downloaded again because it is already in the store. It is also a
5409 convenient way to temporarily stash files, which may be deleted
5410 eventually (@pxref{Invoking guix gc}).
5412 The @command{guix download} command supports the same URIs as used in
5413 package definitions. In particular, it supports @code{mirror://} URIs.
5414 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5415 Guile bindings for GnuTLS are available in the user's environment; when
5416 they are not available, an error is raised. @xref{Guile Preparations,
5417 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5418 GnuTLS-Guile}, for more information.
5420 @command{guix download} verifies HTTPS server certificates by loading
5421 the certificates of X.509 authorities from the directory pointed to by
5422 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5423 Certificates}), unless @option{--no-check-certificate} is used.
5425 The following options are available:
5428 @item --format=@var{fmt}
5430 Write the hash in the format specified by @var{fmt}. For more
5431 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5433 @item --no-check-certificate
5434 Do not validate the X.509 certificates of HTTPS servers.
5436 When using this option, you have @emph{absolutely no guarantee} that you
5437 are communicating with the authentic server responsible for the given
5438 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5440 @item --output=@var{file}
5441 @itemx -o @var{file}
5442 Save the downloaded file to @var{file} instead of adding it to the
5446 @node Invoking guix hash
5447 @section Invoking @command{guix hash}
5449 @cindex @command{guix hash}
5450 The @command{guix hash} command computes the SHA256 hash of a file.
5451 It is primarily a convenience tool for anyone contributing to the
5452 distribution: it computes the cryptographic hash of a file, which can be
5453 used in the definition of a package (@pxref{Defining Packages}).
5455 The general syntax is:
5458 guix hash @var{option} @var{file}
5461 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5462 hash of data read from standard input. @command{guix hash} has the
5467 @item --format=@var{fmt}
5469 Write the hash in the format specified by @var{fmt}.
5471 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5472 (@code{hex} and @code{hexadecimal} can be used as well).
5474 If the @option{--format} option is not specified, @command{guix hash}
5475 will output the hash in @code{nix-base32}. This representation is used
5476 in the definitions of packages.
5480 Compute the hash on @var{file} recursively.
5482 In this case, the hash is computed on an archive containing @var{file},
5483 including its children if it is a directory. Some of the metadata of
5484 @var{file} is part of the archive; for instance, when @var{file} is a
5485 regular file, the hash is different depending on whether @var{file} is
5486 executable or not. Metadata such as time stamps has no impact on the
5487 hash (@pxref{Invoking guix archive}).
5488 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5493 When combined with @option{--recursive}, exclude version control system
5494 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5497 As an example, here is how you would compute the hash of a Git checkout,
5498 which is useful when using the @code{git-fetch} method (@pxref{origin
5502 $ git clone http://example.org/foo.git
5508 @node Invoking guix import
5509 @section Invoking @command{guix import}
5511 @cindex importing packages
5512 @cindex package import
5513 @cindex package conversion
5514 @cindex Invoking @command{guix import}
5515 The @command{guix import} command is useful for people who would like to
5516 add a package to the distribution with as little work as
5517 possible---a legitimate demand. The command knows of a few
5518 repositories from which it can ``import'' package metadata. The result
5519 is a package definition, or a template thereof, in the format we know
5520 (@pxref{Defining Packages}).
5522 The general syntax is:
5525 guix import @var{importer} @var{options}@dots{}
5528 @var{importer} specifies the source from which to import package
5529 metadata, and @var{options} specifies a package identifier and other
5530 options specific to @var{importer}. Currently, the available
5535 Import metadata for the given GNU package. This provides a template
5536 for the latest version of that GNU package, including the hash of its
5537 source tarball, and its canonical synopsis and description.
5539 Additional information such as the package dependencies and its
5540 license needs to be figured out manually.
5542 For example, the following command returns a package definition for
5546 guix import gnu hello
5549 Specific command-line options are:
5552 @item --key-download=@var{policy}
5553 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5554 keys when verifying the package signature. @xref{Invoking guix
5555 refresh, @code{--key-download}}.
5560 Import metadata from the @uref{https://pypi.python.org/, Python Package
5561 Index}@footnote{This functionality requires Guile-JSON to be installed.
5562 @xref{Requirements}.}. Information is taken from the JSON-formatted
5563 description available at @code{pypi.python.org} and usually includes all
5564 the relevant information, including package dependencies. For maximum
5565 efficiency, it is recommended to install the @command{unzip} utility, so
5566 that the importer can unzip Python wheels and gather data from them.
5568 The command below imports metadata for the @code{itsdangerous} Python
5572 guix import pypi itsdangerous
5577 Import metadata from @uref{https://rubygems.org/,
5578 RubyGems}@footnote{This functionality requires Guile-JSON to be
5579 installed. @xref{Requirements}.}. Information is taken from the
5580 JSON-formatted description available at @code{rubygems.org} and includes
5581 most relevant information, including runtime dependencies. There are
5582 some caveats, however. The metadata doesn't distinguish between
5583 synopses and descriptions, so the same string is used for both fields.
5584 Additionally, the details of non-Ruby dependencies required to build
5585 native extensions is unavailable and left as an exercise to the
5588 The command below imports metadata for the @code{rails} Ruby package:
5591 guix import gem rails
5596 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5597 functionality requires Guile-JSON to be installed.
5598 @xref{Requirements}.}.
5599 Information is taken from the JSON-formatted metadata provided through
5600 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5601 relevant information, such as module dependencies. License information
5602 should be checked closely. If Perl is available in the store, then the
5603 @code{corelist} utility will be used to filter core modules out of the
5604 list of dependencies.
5606 The command command below imports metadata for the @code{Acme::Boolean}
5610 guix import cpan Acme::Boolean
5615 @cindex Bioconductor
5616 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5617 central repository for the @uref{http://r-project.org, GNU@tie{}R
5618 statistical and graphical environment}.
5620 Information is extracted from the @code{DESCRIPTION} file of the package.
5622 The command command below imports metadata for the @code{Cairo}
5626 guix import cran Cairo
5629 When @code{--recursive} is added, the importer will traverse the
5630 dependency graph of the given upstream package recursively and generate
5631 package expressions for all those packages that are not yet in Guix.
5633 When @code{--archive=bioconductor} is added, metadata is imported from
5634 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5635 packages for for the analysis and comprehension of high-throughput
5636 genomic data in bioinformatics.
5638 Information is extracted from the @code{DESCRIPTION} file of a package
5639 published on the web interface of the Bioconductor SVN repository.
5641 The command below imports metadata for the @code{GenomicRanges}
5645 guix import cran --archive=bioconductor GenomicRanges
5649 Import metadata from a local copy of the source of the
5650 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5651 relies on the @command{nix-instantiate} command of
5652 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5653 typically written in a mixture of Nix-language and Bash code. This
5654 command only imports the high-level package structure that is written in
5655 the Nix language. It normally includes all the basic fields of a
5658 When importing a GNU package, the synopsis and descriptions are replaced
5659 by their canonical upstream variant.
5661 Usually, you will first need to do:
5664 export NIX_REMOTE=daemon
5668 so that @command{nix-instantiate} does not try to open the Nix database.
5670 As an example, the command below imports the package definition of
5671 LibreOffice (more precisely, it imports the definition of the package
5672 bound to the @code{libreoffice} top-level attribute):
5675 guix import nix ~/path/to/nixpkgs libreoffice
5680 Import metadata from the Haskell community's central package archive
5681 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5682 Cabal files and includes all the relevant information, including package
5685 Specific command-line options are:
5690 Read a Cabal file from standard input.
5691 @item --no-test-dependencies
5693 Do not include dependencies required only by the test suites.
5694 @item --cabal-environment=@var{alist}
5695 @itemx -e @var{alist}
5696 @var{alist} is a Scheme alist defining the environment in which the
5697 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5698 @code{arch}, @code{impl} and a string representing the name of a flag.
5699 The value associated with a flag has to be either the symbol
5700 @code{true} or @code{false}. The value associated with other keys
5701 has to conform to the Cabal file format definition. The default value
5702 associated with the keys @code{os}, @code{arch} and @code{impl} is
5703 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5706 The command below imports metadata for the latest version of the
5707 @code{HTTP} Haskell package without including test dependencies and
5708 specifying the value of the flag @samp{network-uri} as @code{false}:
5711 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5714 A specific package version may optionally be specified by following the
5715 package name by an at-sign and a version number as in the following example:
5718 guix import hackage mtl@@2.1.3.1
5723 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5724 It takes a package name, looks up the package version included in a
5725 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5726 release and uses the @code{hackage} importer to retrieve its metadata.
5727 Note that it is up to you to select an LTS release compatible with the
5728 GHC compiler used by Guix.
5730 Specific command-line options are:
5733 @item --no-test-dependencies
5735 Do not include dependencies required only by the test suites.
5736 @item --lts-version=@var{version}
5737 @itemx -r @var{version}
5738 @var{version} is the desired LTS release version. If omitted the latest
5742 The command below imports metadata for the @code{HTTP} Haskell package
5743 included in the LTS Stackage release version 7.18:
5746 guix import stackage --lts-version=7.18 HTTP
5751 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5752 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5754 Specific command-line options are:
5757 @item --archive=@var{repo}
5758 @itemx -a @var{repo}
5759 @var{repo} identifies the archive repository from which to retrieve the
5760 information. Currently the supported repositories and their identifiers
5764 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5765 identifier. This is the default.
5767 Packages from @code{elpa.gnu.org} are signed with one of the keys
5768 contained in the GnuPG keyring at
5769 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5770 @code{emacs} package (@pxref{Package Installation, ELPA package
5771 signatures,, emacs, The GNU Emacs Manual}).
5774 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5775 @code{melpa-stable} identifier.
5778 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5785 Import metadata from the crates.io Rust package repository
5786 @uref{https://crates.io, crates.io}.
5789 The structure of the @command{guix import} code is modular. It would be
5790 useful to have more importers for other package formats, and your help
5791 is welcome here (@pxref{Contributing}).
5793 @node Invoking guix refresh
5794 @section Invoking @command{guix refresh}
5796 @cindex @command {guix refresh}
5797 The primary audience of the @command{guix refresh} command is developers
5798 of the GNU software distribution. By default, it reports any packages
5799 provided by the distribution that are outdated compared to the latest
5800 upstream version, like this:
5804 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5805 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5808 Alternately, one can specify packages to consider, in which case a
5809 warning is emitted for packages that lack an updater:
5812 $ guix refresh coreutils guile guile-ssh
5813 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5814 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5817 @command{guix refresh} browses the upstream repository of each package and determines
5818 the highest version number of the releases therein. The command
5819 knows how to update specific types of packages: GNU packages, ELPA
5820 packages, etc.---see the documentation for @option{--type} below. There
5821 are many packages, though, for which it lacks a method to determine
5822 whether a new upstream release is available. However, the mechanism is
5823 extensible, so feel free to get in touch with us to add a new method!
5825 When passed @code{--update}, it modifies distribution source files to
5826 update the version numbers and source tarball hashes of those package
5827 recipes (@pxref{Defining Packages}). This is achieved by downloading
5828 each package's latest source tarball and its associated OpenPGP
5829 signature, authenticating the downloaded tarball against its signature
5830 using @command{gpg}, and finally computing its hash. When the public
5831 key used to sign the tarball is missing from the user's keyring, an
5832 attempt is made to automatically retrieve it from a public key server;
5833 when this is successful, the key is added to the user's keyring; otherwise,
5834 @command{guix refresh} reports an error.
5836 The following options are supported:
5840 @item --expression=@var{expr}
5841 @itemx -e @var{expr}
5842 Consider the package @var{expr} evaluates to.
5844 This is useful to precisely refer to a package, as in this example:
5847 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
5850 This command lists the dependents of the ``final'' libc (essentially all
5855 Update distribution source files (package recipes) in place. This is
5856 usually run from a checkout of the Guix source tree (@pxref{Running
5857 Guix Before It Is Installed}):
5860 $ ./pre-inst-env guix refresh -s non-core -u
5863 @xref{Defining Packages}, for more information on package definitions.
5865 @item --select=[@var{subset}]
5866 @itemx -s @var{subset}
5867 Select all the packages in @var{subset}, one of @code{core} or
5870 The @code{core} subset refers to all the packages at the core of the
5871 distribution---i.e., packages that are used to build ``everything
5872 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
5873 changing one of these packages in the distribution entails a rebuild of
5874 all the others. Thus, such updates are an inconvenience to users in
5875 terms of build time or bandwidth used to achieve the upgrade.
5877 The @code{non-core} subset refers to the remaining packages. It is
5878 typically useful in cases where an update of the core packages would be
5881 @item --manifest=@var{file}
5882 @itemx -m @var{file}
5883 Select all the packages from the manifest in @var{file}. This is useful to
5884 check if any packages of the user manifest can be updated.
5886 @item --type=@var{updater}
5887 @itemx -t @var{updater}
5888 Select only packages handled by @var{updater} (may be a comma-separated
5889 list of updaters). Currently, @var{updater} may be one of:
5893 the updater for GNU packages;
5895 the updater for GNOME packages;
5897 the updater for KDE packages;
5899 the updater for X.org packages;
5901 the updater for packages hosted on kernel.org;
5903 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
5905 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
5907 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
5909 the updater for @uref{http://www.cpan.org/, CPAN} packages;
5911 the updater for @uref{https://pypi.python.org, PyPI} packages.
5913 the updater for @uref{https://rubygems.org, RubyGems} packages.
5915 the updater for @uref{https://github.com, GitHub} packages.
5917 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
5919 the updater for @uref{https://www.stackage.org, Stackage} packages.
5921 the updater for @uref{https://crates.io, Crates} packages.
5924 For instance, the following command only checks for updates of Emacs
5925 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
5928 $ guix refresh --type=elpa,cran
5929 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
5930 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
5935 In addition, @command{guix refresh} can be passed one or more package
5936 names, as in this example:
5939 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
5943 The command above specifically updates the @code{emacs} and
5944 @code{idutils} packages. The @code{--select} option would have no
5945 effect in this case.
5947 When considering whether to upgrade a package, it is sometimes
5948 convenient to know which packages would be affected by the upgrade and
5949 should be checked for compatibility. For this the following option may
5950 be used when passing @command{guix refresh} one or more package names:
5954 @item --list-updaters
5956 List available updaters and exit (see @option{--type} above.)
5958 For each updater, display the fraction of packages it covers; at the
5959 end, display the fraction of packages covered by all these updaters.
5961 @item --list-dependent
5963 List top-level dependent packages that would need to be rebuilt as a
5964 result of upgrading one or more packages.
5966 @xref{Invoking guix graph, the @code{reverse-package} type of
5967 @command{guix graph}}, for information on how to visualize the list of
5968 dependents of a package.
5972 Be aware that the @code{--list-dependent} option only
5973 @emph{approximates} the rebuilds that would be required as a result of
5974 an upgrade. More rebuilds might be required under some circumstances.
5977 $ guix refresh --list-dependent flex
5978 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
5979 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
5982 The command above lists a set of packages that could be built to check
5983 for compatibility with an upgraded @code{flex} package.
5985 The following options can be used to customize GnuPG operation:
5989 @item --gpg=@var{command}
5990 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
5991 for in @code{$PATH}.
5993 @item --key-download=@var{policy}
5994 Handle missing OpenPGP keys according to @var{policy}, which may be one
5999 Always download missing OpenPGP keys from the key server, and add them
6000 to the user's GnuPG keyring.
6003 Never try to download missing OpenPGP keys. Instead just bail out.
6006 When a package signed with an unknown OpenPGP key is encountered, ask
6007 the user whether to download it or not. This is the default behavior.
6010 @item --key-server=@var{host}
6011 Use @var{host} as the OpenPGP key server when importing a public key.
6015 The @code{github} updater uses the
6016 @uref{https://developer.github.com/v3/, GitHub API} to query for new
6017 releases. When used repeatedly e.g. when refreshing all packages,
6018 GitHub will eventually refuse to answer any further API requests. By
6019 default 60 API requests per hour are allowed, and a full refresh on all
6020 GitHub packages in Guix requires more than this. Authentication with
6021 GitHub through the use of an API token alleviates these limits. To use
6022 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
6023 token procured from @uref{https://github.com/settings/tokens} or
6027 @node Invoking guix lint
6028 @section Invoking @command{guix lint}
6030 @cindex @command{guix lint}
6031 @cindex package, checking for errors
6032 The @command{guix lint} command is meant to help package developers avoid
6033 common errors and use a consistent style. It runs a number of checks on
6034 a given set of packages in order to find common mistakes in their
6035 definitions. Available @dfn{checkers} include (see
6036 @code{--list-checkers} for a complete list):
6041 Validate certain typographical and stylistic rules about package
6042 descriptions and synopses.
6044 @item inputs-should-be-native
6045 Identify inputs that should most likely be native inputs.
6050 @itemx source-file-name
6051 Probe @code{home-page} and @code{source} URLs and report those that are
6052 invalid. Suggest a @code{mirror://} URL when applicable. Check that
6053 the source file name is meaningful, e.g. is not
6054 just a version number or ``git-checkout'', without a declared
6055 @code{file-name} (@pxref{origin Reference}).
6058 @cindex security vulnerabilities
6059 @cindex CVE, Common Vulnerabilities and Exposures
6060 Report known vulnerabilities found in the Common Vulnerabilities and
6061 Exposures (CVE) databases of the current and past year
6062 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
6065 To view information about a particular vulnerability, visit pages such as:
6069 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
6071 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
6075 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
6076 @code{CVE-2015-7554}.
6078 Package developers can specify in package recipes the
6079 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
6080 name and version of the package when they differ from the name that Guix
6081 uses, as in this example:
6087 ;; CPE calls this package "grub2".
6088 (properties '((cpe-name . "grub2"))))
6092 Warn about obvious source code formatting issues: trailing white space,
6093 use of tabulations, etc.
6096 The general syntax is:
6099 guix lint @var{options} @var{package}@dots{}
6102 If no package is given on the command line, then all packages are checked.
6103 The @var{options} may be zero or more of the following:
6106 @item --list-checkers
6108 List and describe all the available checkers that will be run on packages
6113 Only enable the checkers specified in a comma-separated list using the
6114 names returned by @code{--list-checkers}.
6118 @node Invoking guix size
6119 @section Invoking @command{guix size}
6122 @cindex package size
6124 @cindex @command{guix size}
6125 The @command{guix size} command helps package developers profile the
6126 disk usage of packages. It is easy to overlook the impact of an
6127 additional dependency added to a package, or the impact of using a
6128 single output for a package that could easily be split (@pxref{Packages
6129 with Multiple Outputs}). Such are the typical issues that
6130 @command{guix size} can highlight.
6132 The command can be passed a package specification such as @code{gcc@@4.8}
6133 or @code{guile:debug}, or a file name in the store. Consider this
6137 $ guix size coreutils
6138 store item total self
6139 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6140 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6141 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6142 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6143 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6144 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6148 The store items listed here constitute the @dfn{transitive closure} of
6149 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6150 would be returned by:
6153 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6156 Here the output shows three columns next to store items. The first column,
6157 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6158 the store item---that is, its own size plus the size of all its
6159 dependencies. The next column, labeled ``self'', shows the size of the
6160 item itself. The last column shows the ratio of the size of the item
6161 itself to the space occupied by all the items listed here.
6163 In this example, we see that the closure of Coreutils weighs in at
6164 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6165 large fraction of the closure is not a problem @i{per se} because it is
6166 always available on the system anyway.)
6168 When the package passed to @command{guix size} is available in the
6169 store, @command{guix size} queries the daemon to determine its
6170 dependencies, and measures its size in the store, similar to @command{du
6171 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6174 When the given package is @emph{not} in the store, @command{guix size}
6175 reports information based on the available substitutes
6176 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6177 store items that are not even on disk, only available remotely.
6179 You can also specify several package names:
6182 $ guix size coreutils grep sed bash
6183 store item total self
6184 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6185 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6186 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6187 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6193 In this example we see that the combination of the four packages takes
6194 102.3@tie{}MiB in total, which is much less than the sum of each closure
6195 since they have a lot of dependencies in common.
6197 The available options are:
6201 @item --substitute-urls=@var{urls}
6202 Use substitute information from @var{urls}.
6203 @xref{client-substitute-urls, the same option for @code{guix build}}.
6205 @item --map-file=@var{file}
6206 Write a graphical map of disk usage in PNG format to @var{file}.
6208 For the example above, the map looks like this:
6210 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6211 produced by @command{guix size}}
6213 This option requires that
6214 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6215 installed and visible in Guile's module search path. When that is not
6216 the case, @command{guix size} fails as it tries to load it.
6218 @item --system=@var{system}
6219 @itemx -s @var{system}
6220 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6224 @node Invoking guix graph
6225 @section Invoking @command{guix graph}
6228 @cindex @command{guix graph}
6229 @cindex package dependencies
6230 Packages and their dependencies form a @dfn{graph}, specifically a
6231 directed acyclic graph (DAG). It can quickly become difficult to have a
6232 mental model of the package DAG, so the @command{guix graph} command
6233 provides a visual representation of the DAG. By default,
6234 @command{guix graph} emits a DAG representation in the input format of
6235 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6236 directly to the @command{dot} command of Graphviz. It can also emit an
6237 HTML page with embedded JavaScript code to display a ``chord diagram''
6238 in a Web browser, using the @uref{https://d3js.org/, d3.js} library, or
6239 emit Cypher queries to construct a graph in a graph database supporting
6240 the @uref{http://www.opencypher.org/, openCypher} query language.
6241 The general syntax is:
6244 guix graph @var{options} @var{package}@dots{}
6247 For example, the following command generates a PDF file representing the
6248 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6252 guix graph coreutils | dot -Tpdf > dag.pdf
6255 The output looks like this:
6257 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6259 Nice little graph, no?
6261 But there is more than one graph! The one above is concise: it is the
6262 graph of package objects, omitting implicit inputs such as GCC, libc,
6263 grep, etc. It is often useful to have such a concise graph, but
6264 sometimes one may want to see more details. @command{guix graph} supports
6265 several types of graphs, allowing you to choose the level of detail:
6269 This is the default type used in the example above. It shows the DAG of
6270 package objects, excluding implicit dependencies. It is concise, but
6271 filters out many details.
6273 @item reverse-package
6274 This shows the @emph{reverse} DAG of packages. For example:
6277 guix graph --type=reverse-package ocaml
6280 ... yields the graph of packages that depend on OCaml.
6282 Note that for core packages this can yield huge graphs. If all you want
6283 is to know the number of packages that depend on a given package, use
6284 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6285 @option{--list-dependent}}).
6288 This is the package DAG, @emph{including} implicit inputs.
6290 For instance, the following command:
6293 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6296 ... yields this bigger graph:
6298 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6300 At the bottom of the graph, we see all the implicit inputs of
6301 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6303 Now, note that the dependencies of these implicit inputs---that is, the
6304 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6305 here, for conciseness.
6308 Similar to @code{bag-emerged}, but this time including all the bootstrap
6311 @item bag-with-origins
6312 Similar to @code{bag}, but also showing origins and their dependencies.
6315 This is the most detailed representation: It shows the DAG of
6316 derivations (@pxref{Derivations}) and plain store items. Compared to
6317 the above representation, many additional nodes are visible, including
6318 build scripts, patches, Guile modules, etc.
6320 For this type of graph, it is also possible to pass a @file{.drv} file
6321 name instead of a package name, as in:
6324 guix graph -t derivation `guix system build -d my-config.scm`
6328 All the types above correspond to @emph{build-time dependencies}. The
6329 following graph type represents the @emph{run-time dependencies}:
6333 This is the graph of @dfn{references} of a package output, as returned
6334 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6336 If the given package output is not available in the store, @command{guix
6337 graph} attempts to obtain dependency information from substitutes.
6339 Here you can also pass a store file name instead of a package name. For
6340 example, the command below produces the reference graph of your profile
6341 (which can be big!):
6344 guix graph -t references `readlink -f ~/.guix-profile`
6348 This is the graph of the @dfn{referrers} of a store item, as returned by
6349 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6351 This relies exclusively on local information from your store. For
6352 instance, let us suppose that the current Inkscape is available in 10
6353 profiles on your machine; @command{guix graph -t referrers inkscape}
6354 will show a graph rooted at Inkscape and with those 10 profiles linked
6357 It can help determine what is preventing a store item from being garbage
6362 The available options are the following:
6365 @item --type=@var{type}
6366 @itemx -t @var{type}
6367 Produce a graph output of @var{type}, where @var{type} must be one of
6368 the values listed above.
6371 List the supported graph types.
6373 @item --backend=@var{backend}
6374 @itemx -b @var{backend}
6375 Produce a graph using the selected @var{backend}.
6377 @item --list-backends
6378 List the supported graph backends.
6380 Currently, the available backends are Graphviz and d3.js.
6382 @item --expression=@var{expr}
6383 @itemx -e @var{expr}
6384 Consider the package @var{expr} evaluates to.
6386 This is useful to precisely refer to a package, as in this example:
6389 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6394 @node Invoking guix environment
6395 @section Invoking @command{guix environment}
6397 @cindex reproducible build environments
6398 @cindex development environments
6399 @cindex @command{guix environment}
6400 @cindex environment, package build environment
6401 The purpose of @command{guix environment} is to assist hackers in
6402 creating reproducible development environments without polluting their
6403 package profile. The @command{guix environment} tool takes one or more
6404 packages, builds all of their inputs, and creates a shell
6405 environment to use them.
6407 The general syntax is:
6410 guix environment @var{options} @var{package}@dots{}
6413 The following example spawns a new shell set up for the development of
6417 guix environment guile
6420 If the needed dependencies are not built yet, @command{guix environment}
6421 automatically builds them. The environment of the new shell is an augmented
6422 version of the environment that @command{guix environment} was run in.
6423 It contains the necessary search paths for building the given package
6424 added to the existing environment variables. To create a ``pure''
6425 environment, in which the original environment variables have been unset,
6426 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6427 environment variables such as @code{PATH} in their @file{~/.bashrc}
6428 file. As a consequence, when @code{guix environment} launches it, Bash
6429 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6430 environment variables. It is an error to define such environment
6431 variables in @file{.bashrc}; instead, they should be defined in
6432 @file{.bash_profile}, which is sourced only by log-in shells.
6433 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6434 details on Bash start-up files.}.
6436 @vindex GUIX_ENVIRONMENT
6437 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6438 variable in the shell it spawns; its value is the file name of the
6439 profile of this environment. This allows users to, say, define a
6440 specific prompt for development environments in their @file{.bashrc}
6441 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6444 if [ -n "$GUIX_ENVIRONMENT" ]
6446 export PS1="\u@@\h \w [dev]\$ "
6451 ... or to browse the profile:
6454 $ ls "$GUIX_ENVIRONMENT/bin"
6457 Additionally, more than one package may be specified, in which case the
6458 union of the inputs for the given packages are used. For example, the
6459 command below spawns a shell where all of the dependencies of both Guile
6460 and Emacs are available:
6463 guix environment guile emacs
6466 Sometimes an interactive shell session is not desired. An arbitrary
6467 command may be invoked by placing the @code{--} token to separate the
6468 command from the rest of the arguments:
6471 guix environment guile -- make -j4
6474 In other situations, it is more convenient to specify the list of
6475 packages needed in the environment. For example, the following command
6476 runs @command{python} from an environment containing Python@tie{}2.7 and
6480 guix environment --ad-hoc python2-numpy python-2.7 -- python
6483 Furthermore, one might want the dependencies of a package and also some
6484 additional packages that are not build-time or runtime dependencies, but
6485 are useful when developing nonetheless. Because of this, the
6486 @code{--ad-hoc} flag is positional. Packages appearing before
6487 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6488 added to the environment. Packages appearing after are interpreted as
6489 packages that will be added to the environment directly. For example,
6490 the following command creates a Guix development environment that
6491 additionally includes Git and strace:
6494 guix environment guix --ad-hoc git strace
6497 Sometimes it is desirable to isolate the environment as much as
6498 possible, for maximal purity and reproducibility. In particular, when
6499 using Guix on a host distro that is not GuixSD, it is desirable to
6500 prevent access to @file{/usr/bin} and other system-wide resources from
6501 the development environment. For example, the following command spawns
6502 a Guile REPL in a ``container'' where only the store and the current
6503 working directory are mounted:
6506 guix environment --ad-hoc --container guile -- guile
6510 The @code{--container} option requires Linux-libre 3.19 or newer.
6513 The available options are summarized below.
6516 @item --root=@var{file}
6517 @itemx -r @var{file}
6518 @cindex persistent environment
6519 @cindex garbage collector root, for environments
6520 Make @var{file} a symlink to the profile for this environment, and
6521 register it as a garbage collector root.
6523 This is useful if you want to protect your environment from garbage
6524 collection, to make it ``persistent''.
6526 When this option is omitted, the environment is protected from garbage
6527 collection only for the duration of the @command{guix environment}
6528 session. This means that next time you recreate the same environment,
6529 you could have to rebuild or re-download packages.
6531 @item --expression=@var{expr}
6532 @itemx -e @var{expr}
6533 Create an environment for the package or list of packages that
6534 @var{expr} evaluates to.
6536 For example, running:
6539 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6542 starts a shell with the environment for this specific variant of the
6548 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6551 starts a shell with all the GuixSD base packages available.
6553 The above commands only use the default output of the given packages.
6554 To select other outputs, two element tuples can be specified:
6557 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6560 @item --load=@var{file}
6561 @itemx -l @var{file}
6562 Create an environment for the package or list of packages that the code
6563 within @var{file} evaluates to.
6565 As an example, @var{file} might contain a definition like this
6566 (@pxref{Defining Packages}):
6569 @verbatiminclude environment-gdb.scm
6573 Include all specified packages in the resulting environment, as if an
6574 @i{ad hoc} package were defined with them as inputs. This option is
6575 useful for quickly creating an environment without having to write a
6576 package expression to contain the desired inputs.
6578 For instance, the command:
6581 guix environment --ad-hoc guile guile-sdl -- guile
6584 runs @command{guile} in an environment where Guile and Guile-SDL are
6587 Note that this example implicitly asks for the default output of
6588 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6589 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6590 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6592 This option may be composed with the default behavior of @command{guix
6593 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6594 as packages whose dependencies will be added to the environment, the
6595 default behavior. Packages appearing after are interpreted as packages
6596 that will be added to the environment directly.
6599 Unset existing environment variables when building the new environment.
6600 This has the effect of creating an environment in which search paths
6601 only contain package inputs.
6603 @item --search-paths
6604 Display the environment variable definitions that make up the
6607 @item --system=@var{system}
6608 @itemx -s @var{system}
6609 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6614 Run @var{command} within an isolated container. The current working
6615 directory outside the container is mapped inside the container.
6616 Additionally, a dummy home directory is created that matches the current
6617 user's home directory, and @file{/etc/passwd} is configured accordingly.
6618 The spawned process runs as the current user outside the container, but
6619 has root privileges in the context of the container.
6623 For containers, share the network namespace with the host system.
6624 Containers created without this flag only have access to the loopback
6627 @item --expose=@var{source}[=@var{target}]
6628 For containers, expose the file system @var{source} from the host system
6629 as the read-only file system @var{target} within the container. If
6630 @var{target} is not specified, @var{source} is used as the target mount
6631 point in the container.
6633 The example below spawns a Guile REPL in a container in which the user's
6634 home directory is accessible read-only via the @file{/exchange}
6638 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6641 @item --share=@var{source}[=@var{target}]
6642 For containers, share the file system @var{source} from the host system
6643 as the writable file system @var{target} within the container. If
6644 @var{target} is not specified, @var{source} is used as the target mount
6645 point in the container.
6647 The example below spawns a Guile REPL in a container in which the user's
6648 home directory is accessible for both reading and writing via the
6649 @file{/exchange} directory:
6652 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6656 @command{guix environment}
6657 also supports all of the common build options that @command{guix
6658 build} supports (@pxref{Common Build Options}).
6661 @node Invoking guix publish
6662 @section Invoking @command{guix publish}
6664 @cindex @command{guix publish}
6665 The purpose of @command{guix publish} is to enable users to easily share
6666 their store with others, who can then use it as a substitute server
6667 (@pxref{Substitutes}).
6669 When @command{guix publish} runs, it spawns an HTTP server which allows
6670 anyone with network access to obtain substitutes from it. This means
6671 that any machine running Guix can also act as if it were a build farm,
6672 since the HTTP interface is compatible with Hydra, the software behind
6673 the @code{hydra.gnu.org} build farm.
6675 For security, each substitute is signed, allowing recipients to check
6676 their authenticity and integrity (@pxref{Substitutes}). Because
6677 @command{guix publish} uses the signing key of the system, which is only
6678 readable by the system administrator, it must be started as root; the
6679 @code{--user} option makes it drop root privileges early on.
6681 The signing key pair must be generated before @command{guix publish} is
6682 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6685 The general syntax is:
6688 guix publish @var{options}@dots{}
6691 Running @command{guix publish} without any additional arguments will
6692 spawn an HTTP server on port 8080:
6698 Once a publishing server has been authorized (@pxref{Invoking guix
6699 archive}), the daemon may download substitutes from it:
6702 guix-daemon --substitute-urls=http://example.org:8080
6705 By default, @command{guix publish} compresses archives on the fly as it
6706 serves them. This ``on-the-fly'' mode is convenient in that it requires
6707 no setup and is immediately available. However, when serving lots of
6708 clients, we recommend using the @option{--cache} option, which enables
6709 caching of the archives before they are sent to clients---see below for
6712 As a bonus, @command{guix publish} also serves as a content-addressed
6713 mirror for source files referenced in @code{origin} records
6714 (@pxref{origin Reference}). For instance, assuming @command{guix
6715 publish} is running on @code{example.org}, the following URL returns the
6716 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6717 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6720 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6723 Obviously, these URLs only work for files that are in the store; in
6724 other cases, they return 404 (``Not Found'').
6726 The following options are available:
6729 @item --port=@var{port}
6730 @itemx -p @var{port}
6731 Listen for HTTP requests on @var{port}.
6733 @item --listen=@var{host}
6734 Listen on the network interface for @var{host}. The default is to
6735 accept connections from any interface.
6737 @item --user=@var{user}
6738 @itemx -u @var{user}
6739 Change privileges to @var{user} as soon as possible---i.e., once the
6740 server socket is open and the signing key has been read.
6742 @item --compression[=@var{level}]
6743 @itemx -C [@var{level}]
6744 Compress data using the given @var{level}. When @var{level} is zero,
6745 disable compression. The range 1 to 9 corresponds to different gzip
6746 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6749 Unless @option{--cache} is used, compression occurs on the fly and
6750 the compressed streams are not
6751 cached. Thus, to reduce load on the machine that runs @command{guix
6752 publish}, it may be a good idea to choose a low compression level, to
6753 run @command{guix publish} behind a caching proxy, or to use
6754 @option{--cache}. Using @option{--cache} has the advantage that it
6755 allows @command{guix publish} to add @code{Content-Length} HTTP header
6758 @item --cache=@var{directory}
6759 @itemx -c @var{directory}
6760 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6761 and only serve archives that are in cache.
6763 When this option is omitted, archives and meta-data are created
6764 on-the-fly. This can reduce the available bandwidth, especially when
6765 compression is enabled, since this may become CPU-bound. Another
6766 drawback of the default mode is that the length of archives is not known
6767 in advance, so @command{guix publish} does not add a
6768 @code{Content-Length} HTTP header to its responses, which in turn
6769 prevents clients from knowing the amount of data being downloaded.
6771 Conversely, when @option{--cache} is used, the first request for a store
6772 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6773 background process to @dfn{bake} the archive---computing its
6774 @code{.narinfo} and compressing the archive, if needed. Once the
6775 archive is cached in @var{directory}, subsequent requests succeed and
6776 are served directly from the cache, which guarantees that clients get
6777 the best possible bandwidth.
6779 The ``baking'' process is performed by worker threads. By default, one
6780 thread per CPU core is created, but this can be customized. See
6781 @option{--workers} below.
6783 When @option{--ttl} is used, cached entries are automatically deleted
6784 when they have expired.
6786 @item --workers=@var{N}
6787 When @option{--cache} is used, request the allocation of @var{N} worker
6788 threads to ``bake'' archives.
6790 @item --ttl=@var{ttl}
6791 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6792 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6793 days, @code{1m} means 1 month, and so on.
6795 This allows the user's Guix to keep substitute information in cache for
6796 @var{ttl}. However, note that @code{guix publish} does not itself
6797 guarantee that the store items it provides will indeed remain available
6798 for as long as @var{ttl}.
6800 Additionally, when @option{--cache} is used, cached entries that have
6801 not been accessed for @var{ttl} may be deleted.
6803 @item --nar-path=@var{path}
6804 Use @var{path} as the prefix for the URLs of ``nar'' files
6805 (@pxref{Invoking guix archive, normalized archives}).
6807 By default, nars are served at a URL such as
6808 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6809 change the @code{/nar} part to @var{path}.
6811 @item --public-key=@var{file}
6812 @itemx --private-key=@var{file}
6813 Use the specific @var{file}s as the public/private key pair used to sign
6814 the store items being published.
6816 The files must correspond to the same key pair (the private key is used
6817 for signing and the public key is merely advertised in the signature
6818 metadata). They must contain keys in the canonical s-expression format
6819 as produced by @command{guix archive --generate-key} (@pxref{Invoking
6820 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
6821 @file{/etc/guix/signing-key.sec} are used.
6823 @item --repl[=@var{port}]
6824 @itemx -r [@var{port}]
6825 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
6826 Reference Manual}) on @var{port} (37146 by default). This is used
6827 primarily for debugging a running @command{guix publish} server.
6830 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
6831 instantiate a @code{guix-publish-service-type} service in the @code{services} field
6832 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
6833 @code{guix-publish-service-type}}).
6835 If you are instead running Guix on a ``foreign distro'', follow these
6840 If your host distro uses the systemd init system:
6843 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
6844 /etc/systemd/system/
6845 # systemctl start guix-publish && systemctl enable guix-publish
6849 If your host distro uses the Upstart init system:
6852 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
6853 # start guix-publish
6857 Otherwise, proceed similarly with your distro's init system.
6860 @node Invoking guix challenge
6861 @section Invoking @command{guix challenge}
6863 @cindex reproducible builds
6864 @cindex verifiable builds
6865 @cindex @command{guix challenge}
6867 Do the binaries provided by this server really correspond to the source
6868 code it claims to build? Is a package build process deterministic?
6869 These are the questions the @command{guix challenge} command attempts to
6872 The former is obviously an important question: Before using a substitute
6873 server (@pxref{Substitutes}), one had better @emph{verify} that it
6874 provides the right binaries, and thus @emph{challenge} it. The latter
6875 is what enables the former: If package builds are deterministic, then
6876 independent builds of the package should yield the exact same result,
6877 bit for bit; if a server provides a binary different from the one
6878 obtained locally, it may be either corrupt or malicious.
6880 We know that the hash that shows up in @file{/gnu/store} file names is
6881 the hash of all the inputs of the process that built the file or
6882 directory---compilers, libraries, build scripts,
6883 etc. (@pxref{Introduction}). Assuming deterministic build processes,
6884 one store file name should map to exactly one build output.
6885 @command{guix challenge} checks whether there is, indeed, a single
6886 mapping by comparing the build outputs of several independent builds of
6887 any given store item.
6889 The command output looks like this:
6892 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
6893 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
6894 updating list of substitutes from 'https://guix.example.org'... 100.0%
6895 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
6896 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6897 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6898 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
6899 /gnu/store/@dots{}-git-2.5.0 contents differ:
6900 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
6901 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
6902 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
6903 /gnu/store/@dots{}-pius-2.1.1 contents differ:
6904 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6905 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6906 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
6910 In this example, @command{guix challenge} first scans the store to
6911 determine the set of locally-built derivations---as opposed to store
6912 items that were downloaded from a substitute server---and then queries
6913 all the substitute servers. It then reports those store items for which
6914 the servers obtained a result different from the local build.
6916 @cindex non-determinism, in package builds
6917 As an example, @code{guix.example.org} always gets a different answer.
6918 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
6919 case of Git. This might indicate that the build process of Git is
6920 non-deterministic, meaning that its output varies as a function of
6921 various things that Guix does not fully control, in spite of building
6922 packages in isolated environments (@pxref{Features}). Most common
6923 sources of non-determinism include the addition of timestamps in build
6924 results, the inclusion of random numbers, and directory listings sorted
6925 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
6928 To find out what is wrong with this Git binary, we can do something along
6929 these lines (@pxref{Invoking guix archive}):
6932 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
6933 | guix archive -x /tmp/git
6934 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
6937 This command shows the difference between the files resulting from the
6938 local build, and the files resulting from the build on
6939 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
6940 diffutils, Comparing and Merging Files}). The @command{diff} command
6941 works great for text files. When binary files differ, a better option
6942 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
6943 visualize differences for all kinds of files.
6945 Once you have done that work, you can tell whether the differences are due
6946 to a non-deterministic build process or to a malicious server. We try
6947 hard to remove sources of non-determinism in packages to make it easier
6948 to verify substitutes, but of course, this is a process that
6949 involves not just Guix, but a large part of the free software community.
6950 In the meantime, @command{guix challenge} is one tool to help address
6953 If you are writing packages for Guix, you are encouraged to check
6954 whether @code{hydra.gnu.org} and other substitute servers obtain the
6955 same build result as you did with:
6958 $ guix challenge @var{package}
6962 where @var{package} is a package specification such as
6963 @code{guile@@2.0} or @code{glibc:debug}.
6965 The general syntax is:
6968 guix challenge @var{options} [@var{packages}@dots{}]
6971 When a difference is found between the hash of a locally-built item and
6972 that of a server-provided substitute, or among substitutes provided by
6973 different servers, the command displays it as in the example above and
6974 its exit code is 2 (other non-zero exit codes denote other kinds of
6977 The one option that matters is:
6981 @item --substitute-urls=@var{urls}
6982 Consider @var{urls} the whitespace-separated list of substitute source
6987 Show details about matches (identical contents) in addition to
6988 information about mismatches.
6992 @node Invoking guix copy
6993 @section Invoking @command{guix copy}
6995 @cindex copy, of store items, over SSH
6996 @cindex SSH, copy of store items
6997 @cindex sharing store items across machines
6998 @cindex transferring store items across machines
6999 The @command{guix copy} command copies items from the store of one
7000 machine to that of another machine over a secure shell (SSH)
7001 connection@footnote{This command is available only when Guile-SSH was
7002 found. @xref{Requirements}, for details.}. For example, the following
7003 command copies the @code{coreutils} package, the user's profile, and all
7004 their dependencies over to @var{host}, logged in as @var{user}:
7007 guix copy --to=@var{user}@@@var{host} \
7008 coreutils `readlink -f ~/.guix-profile`
7011 If some of the items to be copied are already present on @var{host},
7012 they are not actually sent.
7014 The command below retrieves @code{libreoffice} and @code{gimp} from
7015 @var{host}, assuming they are available there:
7018 guix copy --from=@var{host} libreoffice gimp
7021 The SSH connection is established using the Guile-SSH client, which is
7022 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
7023 @file{~/.ssh/config}, and uses the SSH agent for authentication.
7025 The key used to sign items that are sent must be accepted by the remote
7026 machine. Likewise, the key used by the remote machine to sign items you
7027 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
7028 own daemon. @xref{Invoking guix archive}, for more information about
7029 store item authentication.
7031 The general syntax is:
7034 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
7037 You must always specify one of the following options:
7040 @item --to=@var{spec}
7041 @itemx --from=@var{spec}
7042 Specify the host to send to or receive from. @var{spec} must be an SSH
7043 spec such as @code{example.org}, @code{charlie@@example.org}, or
7044 @code{charlie@@example.org:2222}.
7047 The @var{items} can be either package names, such as @code{gimp}, or
7048 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
7050 When specifying the name of a package to send, it is first built if
7051 needed, unless @option{--dry-run} was specified. Common build options
7052 are supported (@pxref{Common Build Options}).
7055 @node Invoking guix container
7056 @section Invoking @command{guix container}
7058 @cindex @command{guix container}
7060 As of version @value{VERSION}, this tool is experimental. The interface
7061 is subject to radical change in the future.
7064 The purpose of @command{guix container} is to manipulate processes
7065 running within an isolated environment, commonly known as a
7066 ``container'', typically created by the @command{guix environment}
7067 (@pxref{Invoking guix environment}) and @command{guix system container}
7068 (@pxref{Invoking guix system}) commands.
7070 The general syntax is:
7073 guix container @var{action} @var{options}@dots{}
7076 @var{action} specifies the operation to perform with a container, and
7077 @var{options} specifies the context-specific arguments for the action.
7079 The following actions are available:
7083 Execute a command within the context of a running container.
7088 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
7091 @var{pid} specifies the process ID of the running container.
7092 @var{program} specifies an executable file name within the root file
7093 system of the container. @var{arguments} are the additional options that
7094 will be passed to @var{program}.
7096 The following command launches an interactive login shell inside a
7097 GuixSD container, started by @command{guix system container}, and whose
7101 guix container exec 9001 /run/current-system/profile/bin/bash --login
7104 Note that the @var{pid} cannot be the parent process of a container. It
7105 must be PID 1 of the container or one of its child processes.
7109 @c *********************************************************************
7110 @node GNU Distribution
7111 @chapter GNU Distribution
7113 @cindex Guix System Distribution
7115 Guix comes with a distribution of the GNU system consisting entirely of
7116 free software@footnote{The term ``free'' here refers to the
7117 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
7118 users of that software}.}. The
7119 distribution can be installed on its own (@pxref{System Installation}),
7120 but it is also possible to install Guix as a package manager on top of
7121 an installed GNU/Linux system (@pxref{Installation}). To distinguish
7122 between the two, we refer to the standalone distribution as the Guix
7123 System Distribution, or GuixSD.
7125 The distribution provides core GNU packages such as GNU libc, GCC, and
7126 Binutils, as well as many GNU and non-GNU applications. The complete
7127 list of available packages can be browsed
7128 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7129 running @command{guix package} (@pxref{Invoking guix package}):
7132 guix package --list-available
7135 Our goal is to provide a practical 100% free software distribution of
7136 Linux-based and other variants of GNU, with a focus on the promotion and
7137 tight integration of GNU components, and an emphasis on programs and
7138 tools that help users exert that freedom.
7140 Packages are currently available on the following platforms:
7145 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7148 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7151 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7152 using the EABI hard-float application binary interface (ABI),
7153 and Linux-Libre kernel.
7156 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7157 currently in an experimental stage, with limited support.
7158 @xref{Contributing}, for how to help!
7160 @item mips64el-linux
7161 little-endian 64-bit MIPS processors, specifically the Loongson series,
7162 n32 ABI, and Linux-Libre kernel.
7166 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7169 For information on porting to other architectures or kernels,
7173 * System Installation:: Installing the whole operating system.
7174 * System Configuration:: Configuring the operating system.
7175 * Documentation:: Browsing software user manuals.
7176 * Installing Debugging Files:: Feeding the debugger.
7177 * Security Updates:: Deploying security fixes quickly.
7178 * Package Modules:: Packages from the programmer's viewpoint.
7179 * Packaging Guidelines:: Growing the distribution.
7180 * Bootstrapping:: GNU/Linux built from scratch.
7181 * Porting:: Targeting another platform or kernel.
7184 Building this distribution is a cooperative effort, and you are invited
7185 to join! @xref{Contributing}, for information about how you can help.
7187 @node System Installation
7188 @section System Installation
7190 @cindex installing GuixSD
7191 @cindex Guix System Distribution
7192 This section explains how to install the Guix System Distribution (GuixSD)
7193 on a machine. The Guix package manager can
7194 also be installed on top of a running GNU/Linux system,
7195 @pxref{Installation}.
7199 @c This paragraph is for people reading this from tty2 of the
7200 @c installation image.
7201 You are reading this documentation with an Info reader. For details on
7202 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7203 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7204 Info}. Hit @kbd{l} afterwards to come back here.
7206 Alternately, run @command{info info} in another tty to keep the manual
7212 * Limitations:: What you can expect.
7213 * Hardware Considerations:: Supported hardware.
7214 * USB Stick Installation:: Preparing the installation medium.
7215 * Preparing for Installation:: Networking, partitioning, etc.
7216 * Proceeding with the Installation:: The real thing.
7217 * Installing GuixSD in a VM:: GuixSD playground.
7218 * Building the Installation Image:: How this comes to be.
7222 @subsection Limitations
7224 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7225 not production-ready. It may contain bugs and lack important
7226 features. Thus, if you are looking for a stable production system that
7227 respects your freedom as a computer user, a good solution at this point
7228 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7229 the more established GNU/Linux distributions}. We hope you can soon switch
7230 to the GuixSD without fear, of course. In the meantime, you can
7231 also keep using your distribution and try out the package manager on top
7232 of it (@pxref{Installation}).
7234 Before you proceed with the installation, be aware of the following
7235 noteworthy limitations applicable to version @value{VERSION}:
7239 The installation process does not include a graphical user interface and
7240 requires familiarity with GNU/Linux (see the following subsections to
7241 get a feel of what that means.)
7244 Support for the Logical Volume Manager (LVM) is missing.
7247 More and more system services are provided (@pxref{Services}), but some
7251 More than 5,300 packages are available, but you may
7252 occasionally find that a useful package is missing.
7255 GNOME, Xfce, LXDE, and Enlightenment are available (@pxref{Desktop Services}),
7256 as well as a number of X11 window managers. However, some graphical
7257 applications may be missing, as well as KDE.
7260 You have been warned! But more than a disclaimer, this is an invitation
7261 to report issues (and success stories!), and to join us in improving it.
7262 @xref{Contributing}, for more info.
7265 @node Hardware Considerations
7266 @subsection Hardware Considerations
7268 @cindex hardware support on GuixSD
7269 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7270 builds around the kernel Linux-libre, which means that only hardware for
7271 which free software drivers and firmware exist is supported. Nowadays,
7272 a wide range of off-the-shelf hardware is supported on
7273 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7274 Ethernet controllers. Unfortunately, there are still areas where
7275 hardware vendors deny users control over their own computing, and such
7276 hardware is not supported on GuixSD.
7278 @cindex WiFi, hardware support
7279 One of the main areas where free drivers or firmware are lacking is WiFi
7280 devices. WiFi devices known to work include those using Atheros chips
7281 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7282 driver, and those using Broadcom/AirForce chips (BCM43xx with
7283 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7284 Linux-libre driver. Free firmware exists for both and is available
7285 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7286 (@pxref{operating-system Reference, @code{firmware}}).
7288 @cindex RYF, Respects Your Freedom
7289 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7290 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7291 certification program for hardware products that respect your freedom
7292 and your privacy and ensure that you have control over your device. We
7293 encourage you to check the list of RYF-certified devices.
7295 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7296 web site. It contains a catalog of hardware devices with information
7297 about their support in GNU/Linux.
7300 @node USB Stick Installation
7301 @subsection USB Stick Installation
7303 An installation image for USB sticks can be downloaded from
7304 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
7305 where @var{system} is one of:
7309 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7312 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7315 @c start duplication of authentication part from ``Binary Installation''
7316 Make sure to download the associated @file{.sig} file and to verify the
7317 authenticity of the image against it, along these lines:
7320 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7321 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7324 If that command fails because you do not have the required public key,
7325 then run this command to import it:
7328 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7332 and rerun the @code{gpg --verify} command.
7335 This image contains a single partition with the tools necessary for an
7336 installation. It is meant to be copied @emph{as is} to a large-enough
7339 To copy the image to a USB stick, follow these steps:
7343 Decompress the image using the @command{xz} command:
7346 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
7350 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7351 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7352 copy the image with:
7355 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
7359 Access to @file{/dev/sdX} usually requires root privileges.
7362 Once this is done, you should be able to reboot the system and boot from
7363 the USB stick. The latter usually requires you to get in the BIOS or
7364 UEFI boot menu, where you can choose to boot from the USB stick.
7366 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7367 GuixSD in a virtual machine (VM).
7369 @node Preparing for Installation
7370 @subsection Preparing for Installation
7372 Once you have successfully booted the image on the USB stick, you should
7373 end up with a root prompt. Several console TTYs are configured and can
7374 be used to run commands as root. TTY2 shows this documentation,
7375 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7376 Stand-alone GNU Info}). The installation system runs the GPM mouse
7377 daemon, which allows you to select text with the left mouse button and
7378 to paste it with the middle button.
7381 Installation requires access to the Internet so that any missing
7382 dependencies of your system configuration can be downloaded. See the
7383 ``Networking'' section below.
7386 The installation system includes many common tools needed for this task.
7387 But it is also a full-blown GuixSD system, which means that you can
7388 install additional packages, should you need it, using @command{guix
7389 package} (@pxref{Invoking guix package}).
7391 @subsubsection Keyboard Layout
7393 @cindex keyboard layout
7394 The installation image uses the US qwerty keyboard layout. If you want
7395 to change it, you can use the @command{loadkeys} command. For example,
7396 the following command selects the Dvorak keyboard layout:
7402 See the files under @file{/run/current-system/profile/share/keymaps} for
7403 a list of available keyboard layouts. Run @command{man loadkeys} for
7406 @subsubsection Networking
7408 Run the following command see what your network interfaces are called:
7415 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7421 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7422 Wired interfaces have a name starting with @samp{e}; for example, the
7423 interface corresponding to the first on-board Ethernet controller is
7424 called @samp{eno1}. Wireless interfaces have a name starting with
7425 @samp{w}, like @samp{w1p2s0}.
7428 @item Wired connection
7429 To configure a wired network run the following command, substituting
7430 @var{interface} with the name of the wired interface you want to use.
7433 ifconfig @var{interface} up
7436 @item Wireless connection
7439 To configure wireless networking, you can create a configuration file
7440 for the @command{wpa_supplicant} configuration tool (its location is not
7441 important) using one of the available text editors such as
7445 zile wpa_supplicant.conf
7448 As an example, the following stanza can go to this file and will work
7449 for many wireless networks, provided you give the actual SSID and
7450 passphrase for the network you are connecting to:
7454 ssid="@var{my-ssid}"
7456 psk="the network's secret passphrase"
7460 Start the wireless service and run it in the background with the
7461 following command (substitute @var{interface} with the name of the
7462 network interface you want to use):
7465 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7468 Run @command{man wpa_supplicant} for more information.
7472 At this point, you need to acquire an IP address. On a network where IP
7473 addresses are automatically assigned @i{via} DHCP, you can run:
7476 dhclient -v @var{interface}
7479 Try to ping a server to see if networking is up and running:
7485 Setting up network access is almost always a requirement because the
7486 image does not contain all the software and tools that may be needed.
7488 @cindex installing over SSH
7489 If you want to, you can continue the installation remotely by starting
7493 herd start ssh-daemon
7496 Make sure to either set a password with @command{passwd}, or configure
7497 OpenSSH public key authentication before logging in.
7499 @subsubsection Disk Partitioning
7501 Unless this has already been done, the next step is to partition, and
7502 then format the target partition(s).
7504 The installation image includes several partitioning tools, including
7505 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7506 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7507 the partition layout you want:
7513 If your disk uses the GUID Partition Table (GPT) format and you plan to
7514 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7515 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7518 @cindex EFI, installation
7519 @cindex UEFI, installation
7520 @cindex ESP, EFI system partition
7521 If you instead wish to use EFI-based GRUB, a FAT32 @dfn{EFI System Partition}
7522 (ESP) is required. This partition should be mounted at @file{/boot/efi} and
7523 must have the @code{esp} flag set. E.g., for @command{parted}:
7526 parted /dev/sda set 1 esp on
7529 Once you are done partitioning the target hard disk drive, you have to
7530 create a file system on the relevant partition(s)@footnote{Currently
7531 GuixSD only supports ext4 and btrfs file systems. In particular, code
7532 that reads partition UUIDs and labels only works for these file system
7535 Preferably, assign partitions a label so that you can easily and
7536 reliably refer to them in @code{file-system} declarations (@pxref{File
7537 Systems}). This is typically done using the @code{-L} option of
7538 @command{mkfs.ext4} and related commands. So, assuming the target root
7539 partition lives at @file{/dev/sda1}, a file system with the label
7540 @code{my-root} can be created with:
7543 mkfs.ext4 -L my-root /dev/sda1
7546 @cindex encrypted disk
7547 If you are instead planning to encrypt the root partition, you can use
7548 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7549 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7550 @code{man cryptsetup}} for more information.) Assuming you want to
7551 store the root partition on @file{/dev/sda1}, the command sequence would
7552 be along these lines:
7555 cryptsetup luksFormat /dev/sda1
7556 cryptsetup open --type luks /dev/sda1 my-partition
7557 mkfs.ext4 -L my-root /dev/mapper/my-partition
7560 Once that is done, mount the target root partition under @file{/mnt}
7561 with a command like (again, assuming @code{my-root} is the label of the
7565 mount LABEL=my-root /mnt
7568 Also mount any other partitions you would like to use on the target
7569 system relative to this path. If you have @file{/boot} on a separate
7570 partition for example, mount it at @file{/mnt/boot} now so it is found
7571 by @code{guix system init} afterwards.
7573 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7574 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7575 sure to initialize them with @command{mkswap}. Assuming you have one
7576 swap partition on @file{/dev/sda2}, you would run:
7583 Alternatively, you may use a swap file. For example, assuming that in
7584 the new system you want to use the file @file{/swapfile} as a swap file,
7585 you would run@footnote{This example will work for many types of file
7586 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7587 btrfs), the required steps may be different. For details, see the
7588 manual pages for @command{mkswap} and @command{swapon}.}:
7591 # This is 10 GiB of swap space. Adjust "count" to change the size.
7592 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7593 # For security, make the file readable and writable only by root.
7594 chmod 600 /mnt/swapfile
7595 mkswap /mnt/swapfile
7596 swapon /mnt/swapfile
7599 Note that if you have encrypted the root partition and created a swap
7600 file in its file system as described above, then the encryption also
7601 protects the swap file, just like any other file in that file system.
7603 @node Proceeding with the Installation
7604 @subsection Proceeding with the Installation
7606 With the target partitions ready and the target root mounted on
7607 @file{/mnt}, we're ready to go. First, run:
7610 herd start cow-store /mnt
7613 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7614 during the installation phase are written to the target disk on @file{/mnt}
7615 rather than kept in memory. This is necessary because the first phase of
7616 the @command{guix system init} command (see below) entails downloads or
7617 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7619 Next, you have to edit a file and
7620 provide the declaration of the operating system to be installed. To
7621 that end, the installation system comes with three text editors: GNU nano
7622 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7623 nvi (a clone of the original BSD @command{vi} editor).
7624 We strongly recommend storing that file on the target root file system, say,
7625 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7626 configuration file once you have rebooted into the newly-installed system.
7628 @xref{Using the Configuration System}, for an overview of the
7629 configuration file. The example configurations discussed in that
7630 section are available under @file{/etc/configuration} in the
7631 installation image. Thus, to get started with a system configuration
7632 providing a graphical display server (a ``desktop'' system), you can run
7633 something along these lines:
7637 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7638 # zile /mnt/etc/config.scm
7641 You should pay attention to what your configuration file contains, and
7646 Make sure the @code{grub-configuration} form refers to the device you
7647 want to install GRUB on. You also need to specify the @code{grub-efi}
7648 package if you wish to use native UEFI boot.
7651 Be sure that your partition labels match the value of their respective
7652 @code{device} fields in your @code{file-system} configuration, assuming
7653 your @code{file-system} configuration sets the value of @code{title} to
7657 If there are encrypted or RAID partitions, make sure to add a
7658 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7661 Once you are done preparing the configuration file, the new system must
7662 be initialized (remember that the target root file system is mounted
7666 guix system init /mnt/etc/config.scm /mnt
7670 This copies all the necessary files and installs GRUB on
7671 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7672 more information, @pxref{Invoking guix system}. This command may trigger
7673 downloads or builds of missing packages, which can take some time.
7675 Once that command has completed---and hopefully succeeded!---you can run
7676 @command{reboot} and boot into the new system. The @code{root} password
7677 in the new system is initially empty; other users' passwords need to be
7678 initialized by running the @command{passwd} command as @code{root},
7679 unless your configuration specifies otherwise
7680 (@pxref{user-account-password, user account passwords}).
7682 @cindex upgrading GuixSD
7683 From then on, you can update GuixSD whenever you want by running
7684 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7685 then running @command{guix system reconfigure} to build a new system
7686 generation with the latest packages and services (@pxref{Invoking guix
7687 system}). We recommend doing that regularly so that your system
7688 includes the latest security updates (@pxref{Security Updates}).
7690 Join us on @code{#guix} on the Freenode IRC network or on
7691 @file{guix-devel@@gnu.org} to share your experience---good or not so
7694 @node Installing GuixSD in a VM
7695 @subsection Installing GuixSD in a Virtual Machine
7697 @cindex virtual machine, GuixSD installation
7698 @cindex virtual private server (VPS)
7699 @cindex VPS (virtual private server)
7700 If you'd like to install GuixSD in a virtual machine (VM) or on a
7701 virtual private server (VPS) rather than on your beloved machine, this
7704 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7705 disk image, follow these steps:
7709 First, retrieve and decompress the GuixSD installation image as
7710 described previously (@pxref{USB Stick Installation}).
7713 Create a disk image that will hold the installed system. To make a
7714 qcow2-formatted disk image, use the @command{qemu-img} command:
7717 qemu-img create -f qcow2 guixsd.img 5G
7720 This will create a 5GB file.
7723 Boot the USB installation image in an VM:
7726 qemu-system-x86_64 -m 1024 -smp 1 \
7727 -net user -net nic,model=virtio -boot menu=on \
7728 -drive file=guixsd-usb-install-@value{VERSION}.@var{system} \
7729 -drive file=guixsd.img
7732 The ordering of the drives matters.
7734 In the VM console, quickly press the @kbd{F12} key to enter the boot
7735 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7739 You're now root in the VM, proceed with the installation process.
7740 @xref{Preparing for Installation}, and follow the instructions.
7743 Once installation is complete, you can boot the system that's on your
7744 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
7747 @node Building the Installation Image
7748 @subsection Building the Installation Image
7750 @cindex installation image
7751 The installation image described above was built using the @command{guix
7752 system} command, specifically:
7754 @c FIXME: 1G is too much; see <http://bugs.gnu.org/23077>.
7756 guix system disk-image --image-size=1G gnu/system/install.scm
7759 Have a look at @file{gnu/system/install.scm} in the source tree,
7760 and see also @ref{Invoking guix system} for more information
7761 about the installation image.
7763 @node System Configuration
7764 @section System Configuration
7766 @cindex system configuration
7767 The Guix System Distribution supports a consistent whole-system configuration
7768 mechanism. By that we mean that all aspects of the global system
7769 configuration---such as the available system services, timezone and
7770 locale settings, user accounts---are declared in a single place. Such
7771 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
7773 One of the advantages of putting all the system configuration under the
7774 control of Guix is that it supports transactional system upgrades, and
7775 makes it possible to roll back to a previous system instantiation,
7776 should something go wrong with the new one (@pxref{Features}). Another
7777 advantage is that it makes it easy to replicate the exact same configuration
7778 across different machines, or at different points in time, without
7779 having to resort to additional administration tools layered on top of
7780 the own tools of the system.
7781 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
7783 This section describes this mechanism. First we focus on the system
7784 administrator's viewpoint---explaining how the system is configured and
7785 instantiated. Then we show how this mechanism can be extended, for
7786 instance to support new system services.
7789 * Using the Configuration System:: Customizing your GNU system.
7790 * operating-system Reference:: Detail of operating-system declarations.
7791 * File Systems:: Configuring file system mounts.
7792 * Mapped Devices:: Block device extra processing.
7793 * User Accounts:: Specifying user accounts.
7794 * Locales:: Language and cultural convention settings.
7795 * Services:: Specifying system services.
7796 * Setuid Programs:: Programs running with root privileges.
7797 * X.509 Certificates:: Authenticating HTTPS servers.
7798 * Name Service Switch:: Configuring libc's name service switch.
7799 * Initial RAM Disk:: Linux-Libre bootstrapping.
7800 * Bootloader Configuration:: Configuring the boot loader.
7801 * Invoking guix system:: Instantiating a system configuration.
7802 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
7803 * Defining Services:: Adding new service definitions.
7806 @node Using the Configuration System
7807 @subsection Using the Configuration System
7809 The operating system is configured by providing an
7810 @code{operating-system} declaration in a file that can then be passed to
7811 the @command{guix system} command (@pxref{Invoking guix system}). A
7812 simple setup, with the default system services, the default Linux-Libre
7813 kernel, initial RAM disk, and boot loader looks like this:
7815 @findex operating-system
7817 @include os-config-bare-bones.texi
7820 This example should be self-describing. Some of the fields defined
7821 above, such as @code{host-name} and @code{bootloader}, are mandatory.
7822 Others, such as @code{packages} and @code{services}, can be omitted, in
7823 which case they get a default value.
7825 Below we discuss the effect of some of the most important fields
7826 (@pxref{operating-system Reference}, for details about all the available
7827 fields), and how to @dfn{instantiate} the operating system using
7828 @command{guix system}.
7830 @unnumberedsubsubsec Globally-Visible Packages
7832 @vindex %base-packages
7833 The @code{packages} field lists packages that will be globally visible
7834 on the system, for all user accounts---i.e., in every user's @code{PATH}
7835 environment variable---in addition to the per-user profiles
7836 (@pxref{Invoking guix package}). The @var{%base-packages} variable
7837 provides all the tools one would expect for basic user and administrator
7838 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
7839 the GNU Zile lightweight text editor, @command{find}, @command{grep},
7840 etc. The example above adds tcpdump to those, taken from the @code{(gnu
7841 packages admin)} module (@pxref{Package Modules}). The
7842 @code{(list package output)} syntax can be used to add a specific output
7846 (use-modules (gnu packages))
7847 (use-modules (gnu packages dns))
7851 (packages (cons (list bind "utils")
7855 @findex specification->package
7856 Referring to packages by variable name, like @var{tcpdump} above, has
7857 the advantage of being unambiguous; it also allows typos and such to be
7858 diagnosed right away as ``unbound variables''. The downside is that one
7859 needs to know which module defines which package, and to augment the
7860 @code{use-package-modules} line accordingly. To avoid that, one can use
7861 the @code{specification->package} procedure of the @code{(gnu packages)}
7862 module, which returns the best package for a given name or name and
7866 (use-modules (gnu packages))
7870 (packages (append (map specification->package
7871 '("tcpdump" "htop" "gnupg@@2.0"))
7875 @unnumberedsubsubsec System Services
7878 @vindex %base-services
7879 The @code{services} field lists @dfn{system services} to be made
7880 available when the system starts (@pxref{Services}).
7881 The @code{operating-system} declaration above specifies that, in
7882 addition to the basic services, we want the @command{lshd} secure shell
7883 daemon listening on port 2222 (@pxref{Networking Services,
7884 @code{lsh-service}}). Under the hood,
7885 @code{lsh-service} arranges so that @code{lshd} is started with the
7886 right command-line options, possibly with supporting configuration files
7887 generated as needed (@pxref{Defining Services}).
7889 @cindex customization, of services
7890 @findex modify-services
7891 Occasionally, instead of using the base services as is, you will want to
7892 customize them. To do this, use @code{modify-services} (@pxref{Service
7893 Reference, @code{modify-services}}) to modify the list.
7895 For example, suppose you want to modify @code{guix-daemon} and Mingetty
7896 (the console log-in) in the @var{%base-services} list (@pxref{Base
7897 Services, @code{%base-services}}). To do that, you can write the
7898 following in your operating system declaration:
7901 (define %my-services
7902 ;; My very own list of services.
7903 (modify-services %base-services
7904 (guix-service-type config =>
7907 (use-substitutes? #f)
7908 (extra-options '("--gc-keep-derivations"))))
7909 (mingetty-service-type config =>
7910 (mingetty-configuration
7911 (inherit config)))))
7915 (services %my-services))
7918 This changes the configuration---i.e., the service parameters---of the
7919 @code{guix-service-type} instance, and that of all the
7920 @code{mingetty-service-type} instances in the @var{%base-services} list.
7921 Observe how this is accomplished: first, we arrange for the original
7922 configuration to be bound to the identifier @code{config} in the
7923 @var{body}, and then we write the @var{body} so that it evaluates to the
7924 desired configuration. In particular, notice how we use @code{inherit}
7925 to create a new configuration which has the same values as the old
7926 configuration, but with a few modifications.
7928 @cindex encrypted disk
7929 The configuration for a typical ``desktop'' usage, with an encrypted
7930 root partition, the X11 display
7931 server, GNOME and Xfce (users can choose which of these desktop
7932 environments to use at the log-in screen by pressing @kbd{F1}), network
7933 management, power management, and more, would look like this:
7936 @include os-config-desktop.texi
7939 A graphical UEFI system with a choice of lightweight window managers
7940 instead of full-blown desktop environments would look like this:
7943 @include os-config-lightweight-desktop.texi
7946 @xref{Desktop Services}, for the exact list of services provided by
7947 @var{%desktop-services}. @xref{X.509 Certificates}, for background
7948 information about the @code{nss-certs} package that is used here.
7950 Again, @var{%desktop-services} is just a list of service objects. If
7951 you want to remove services from there, you can do so using the
7952 procedures for list filtering (@pxref{SRFI-1 Filtering and
7953 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
7954 following expression returns a list that contains all the services in
7955 @var{%desktop-services} minus the Avahi service:
7958 (remove (lambda (service)
7959 (eq? (service-kind service) avahi-service-type))
7963 @unnumberedsubsubsec Instantiating the System
7965 Assuming the @code{operating-system} declaration
7966 is stored in the @file{my-system-config.scm}
7967 file, the @command{guix system reconfigure my-system-config.scm} command
7968 instantiates that configuration, and makes it the default GRUB boot
7969 entry (@pxref{Invoking guix system}).
7971 The normal way to change the system configuration is by updating this
7972 file and re-running @command{guix system reconfigure}. One should never
7973 have to touch files in @file{/etc} or to run commands that modify the
7974 system state such as @command{useradd} or @command{grub-install}. In
7975 fact, you must avoid that since that would not only void your warranty
7976 but also prevent you from rolling back to previous versions of your
7977 system, should you ever need to.
7979 @cindex roll-back, of the operating system
7980 Speaking of roll-back, each time you run @command{guix system
7981 reconfigure}, a new @dfn{generation} of the system is created---without
7982 modifying or deleting previous generations. Old system generations get
7983 an entry in the bootloader boot menu, allowing you to boot them in case
7984 something went wrong with the latest generation. Reassuring, no? The
7985 @command{guix system list-generations} command lists the system
7986 generations available on disk. It is also possible to roll back the
7987 system via the commands @command{guix system roll-back} and
7988 @command{guix system switch-generation}.
7990 Although the command @command{guix system reconfigure} will not modify
7991 previous generations, must take care when the current generation is not
7992 the latest (e.g., after invoking @command{guix system roll-back}), since
7993 the operation might overwrite a later generation (@pxref{Invoking guix
7996 @unnumberedsubsubsec The Programming Interface
7998 At the Scheme level, the bulk of an @code{operating-system} declaration
7999 is instantiated with the following monadic procedure (@pxref{The Store
8002 @deffn {Monadic Procedure} operating-system-derivation os
8003 Return a derivation that builds @var{os}, an @code{operating-system}
8004 object (@pxref{Derivations}).
8006 The output of the derivation is a single directory that refers to all
8007 the packages, configuration files, and other supporting files needed to
8008 instantiate @var{os}.
8011 This procedure is provided by the @code{(gnu system)} module. Along
8012 with @code{(gnu services)} (@pxref{Services}), this module contains the
8013 guts of GuixSD. Make sure to visit it!
8016 @node operating-system Reference
8017 @subsection @code{operating-system} Reference
8019 This section summarizes all the options available in
8020 @code{operating-system} declarations (@pxref{Using the Configuration
8023 @deftp {Data Type} operating-system
8024 This is the data type representing an operating system configuration.
8025 By that, we mean all the global system configuration, not per-user
8026 configuration (@pxref{Using the Configuration System}).
8029 @item @code{kernel} (default: @var{linux-libre})
8030 The package object of the operating system kernel to use@footnote{Currently
8031 only the Linux-libre kernel is supported. In the future, it will be
8032 possible to use the GNU@tie{}Hurd.}.
8034 @item @code{kernel-arguments} (default: @code{'()})
8035 List of strings or gexps representing additional arguments to pass on
8036 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
8038 @item @code{bootloader}
8039 The system bootloader configuration object. @xref{Bootloader Configuration}.
8041 @item @code{initrd} (default: @code{base-initrd})
8043 @cindex initial RAM disk
8044 A two-argument monadic procedure that returns an initial RAM disk for
8045 the Linux kernel. @xref{Initial RAM Disk}.
8047 @item @code{firmware} (default: @var{%base-firmware})
8049 List of firmware packages loadable by the operating system kernel.
8051 The default includes firmware needed for Atheros- and Broadcom-based
8052 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
8053 respectively). @xref{Hardware Considerations}, for more info on
8056 @item @code{host-name}
8059 @item @code{hosts-file}
8061 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
8062 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
8063 Reference Manual}). The default is a file with entries for
8064 @code{localhost} and @var{host-name}.
8066 @item @code{mapped-devices} (default: @code{'()})
8067 A list of mapped devices. @xref{Mapped Devices}.
8069 @item @code{file-systems}
8070 A list of file systems. @xref{File Systems}.
8072 @item @code{swap-devices} (default: @code{'()})
8073 @cindex swap devices
8074 A list of strings identifying devices or files to be used for ``swap
8075 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
8076 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
8077 It is possible to specify a swap file in a file system on a mapped
8078 device, provided that the necessary device mapping and file system are
8079 also specified. @xref{Mapped Devices} and @ref{File Systems}.
8081 @item @code{users} (default: @code{%base-user-accounts})
8082 @itemx @code{groups} (default: @var{%base-groups})
8083 List of user accounts and groups. @xref{User Accounts}.
8085 @item @code{skeletons} (default: @code{(default-skeletons)})
8086 A list target file name/file-like object tuples (@pxref{G-Expressions,
8087 file-like objects}). These are the skeleton files that will be added to
8088 the home directory of newly-created user accounts.
8090 For instance, a valid value may look like this:
8093 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
8094 (".guile" ,(plain-file "guile"
8095 "(use-modules (ice-9 readline))
8096 (activate-readline)")))
8099 @item @code{issue} (default: @var{%default-issue})
8100 A string denoting the contents of the @file{/etc/issue} file, which is
8101 displayed when users log in on a text console.
8103 @item @code{packages} (default: @var{%base-packages})
8104 The set of packages installed in the global profile, which is accessible
8105 at @file{/run/current-system/profile}.
8107 The default set includes core utilities and it is good practice to
8108 install non-core utilities in user profiles (@pxref{Invoking guix
8111 @item @code{timezone}
8112 A timezone identifying string---e.g., @code{"Europe/Paris"}.
8114 You can run the @command{tzselect} command to find out which timezone
8115 string corresponds to your region. Choosing an invalid timezone name
8116 causes @command{guix system} to fail.
8118 @item @code{locale} (default: @code{"en_US.utf8"})
8119 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
8120 Library Reference Manual}). @xref{Locales}, for more information.
8122 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
8123 The list of locale definitions to be compiled and that may be used at
8124 run time. @xref{Locales}.
8126 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
8127 The list of GNU@tie{}libc packages whose locale data and tools are used
8128 to build the locale definitions. @xref{Locales}, for compatibility
8129 considerations that justify this option.
8131 @item @code{name-service-switch} (default: @var{%default-nss})
8132 Configuration of the libc name service switch (NSS)---a
8133 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
8136 @item @code{services} (default: @var{%base-services})
8137 A list of service objects denoting system services. @xref{Services}.
8139 @item @code{pam-services} (default: @code{(base-pam-services)})
8141 @cindex pluggable authentication modules
8142 Linux @dfn{pluggable authentication module} (PAM) services.
8143 @c FIXME: Add xref to PAM services section.
8145 @item @code{setuid-programs} (default: @var{%setuid-programs})
8146 List of string-valued G-expressions denoting setuid programs.
8147 @xref{Setuid Programs}.
8149 @item @code{sudoers-file} (default: @var{%sudoers-specification})
8150 @cindex sudoers file
8151 The contents of the @file{/etc/sudoers} file as a file-like object
8152 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
8154 This file specifies which users can use the @command{sudo} command, what
8155 they are allowed to do, and what privileges they may gain. The default
8156 is that only @code{root} and members of the @code{wheel} group may use
8163 @subsection File Systems
8165 The list of file systems to be mounted is specified in the
8166 @code{file-systems} field of the operating system declaration
8167 (@pxref{Using the Configuration System}). Each file system is declared
8168 using the @code{file-system} form, like this:
8172 (mount-point "/home")
8173 (device "/dev/sda3")
8177 As usual, some of the fields are mandatory---those shown in the example
8178 above---while others can be omitted. These are described below.
8180 @deftp {Data Type} file-system
8181 Objects of this type represent file systems to be mounted. They
8182 contain the following members:
8186 This is a string specifying the type of the file system---e.g.,
8189 @item @code{mount-point}
8190 This designates the place where the file system is to be mounted.
8193 This names the ``source'' of the file system. By default it is the name
8194 of a node under @file{/dev}, but its meaning depends on the @code{title}
8195 field described below.
8197 @item @code{title} (default: @code{'device})
8198 This is a symbol that specifies how the @code{device} field is to be
8201 When it is the symbol @code{device}, then the @code{device} field is
8202 interpreted as a file name; when it is @code{label}, then @code{device}
8203 is interpreted as a partition label name; when it is @code{uuid},
8204 @code{device} is interpreted as a partition unique identifier (UUID).
8206 UUIDs may be converted from their string representation (as shown by the
8207 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8208 @code{uuid} form expects 16-byte UUIDs as defined in
8209 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8210 form of UUID used by the ext2 family of file systems and others, but it
8211 is different from ``UUIDs'' found in FAT file systems, for instance.},
8216 (mount-point "/home")
8219 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8222 The @code{label} and @code{uuid} options offer a way to refer to disk
8223 partitions without having to hard-code their actual device
8224 name@footnote{Note that, while it is tempting to use
8225 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8226 result, this is not recommended: These special device nodes are created
8227 by the udev daemon and may be unavailable at the time the device is
8230 However, when the source of a file system is a mapped device (@pxref{Mapped
8231 Devices}), its @code{device} field @emph{must} refer to the mapped
8232 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8233 @code{title} must be set to @code{'device}. This is required so that
8234 the system knows that mounting the file system depends on having the
8235 corresponding device mapping established.
8237 @item @code{flags} (default: @code{'()})
8238 This is a list of symbols denoting mount flags. Recognized flags
8239 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8240 access to special files), @code{no-suid} (ignore setuid and setgid
8241 bits), and @code{no-exec} (disallow program execution.)
8243 @item @code{options} (default: @code{#f})
8244 This is either @code{#f}, or a string denoting mount options.
8246 @item @code{mount?} (default: @code{#t})
8247 This value indicates whether to automatically mount the file system when
8248 the system is brought up. When set to @code{#f}, the file system gets
8249 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8250 is not automatically mounted.
8252 @item @code{needed-for-boot?} (default: @code{#f})
8253 This Boolean value indicates whether the file system is needed when
8254 booting. If that is true, then the file system is mounted when the
8255 initial RAM disk (initrd) is loaded. This is always the case, for
8256 instance, for the root file system.
8258 @item @code{check?} (default: @code{#t})
8259 This Boolean indicates whether the file system needs to be checked for
8260 errors before being mounted.
8262 @item @code{create-mount-point?} (default: @code{#f})
8263 When true, the mount point is created if it does not exist yet.
8265 @item @code{dependencies} (default: @code{'()})
8266 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8267 representing file systems that must be mounted or mapped devices that
8268 must be opened before (and unmounted or closed after) this one.
8270 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8271 a dependency of @file{/sys/fs/cgroup/cpu} and
8272 @file{/sys/fs/cgroup/memory}.
8274 Another example is a file system that depends on a mapped device, for
8275 example for an encrypted partition (@pxref{Mapped Devices}).
8279 The @code{(gnu system file-systems)} exports the following useful
8282 @defvr {Scheme Variable} %base-file-systems
8283 These are essential file systems that are required on normal systems,
8284 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8285 below.) Operating system declarations should always contain at least
8289 @defvr {Scheme Variable} %pseudo-terminal-file-system
8290 This is the file system to be mounted as @file{/dev/pts}. It supports
8291 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8292 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8293 Manual}). Pseudo-terminals are used by terminal emulators such as
8297 @defvr {Scheme Variable} %shared-memory-file-system
8298 This file system is mounted as @file{/dev/shm} and is used to support
8299 memory sharing across processes (@pxref{Memory-mapped I/O,
8300 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8303 @defvr {Scheme Variable} %immutable-store
8304 This file system performs a read-only ``bind mount'' of
8305 @file{/gnu/store}, making it read-only for all the users including
8306 @code{root}. This prevents against accidental modification by software
8307 running as @code{root} or by system administrators.
8309 The daemon itself is still able to write to the store: it remounts it
8310 read-write in its own ``name space.''
8313 @defvr {Scheme Variable} %binary-format-file-system
8314 The @code{binfmt_misc} file system, which allows handling of arbitrary
8315 executable file types to be delegated to user space. This requires the
8316 @code{binfmt.ko} kernel module to be loaded.
8319 @defvr {Scheme Variable} %fuse-control-file-system
8320 The @code{fusectl} file system, which allows unprivileged users to mount
8321 and unmount user-space FUSE file systems. This requires the
8322 @code{fuse.ko} kernel module to be loaded.
8325 @node Mapped Devices
8326 @subsection Mapped Devices
8328 @cindex device mapping
8329 @cindex mapped devices
8330 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8331 such as a hard disk partition, can be @dfn{mapped} into another device,
8332 usually in @code{/dev/mapper/},
8333 with additional processing over the data that flows through
8334 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8335 concept of a ``mapped device'' and that of a file system: both boil down
8336 to @emph{translating} input/output operations made on a file to
8337 operations on its backing store. Thus, the Hurd implements mapped
8338 devices, like file systems, using the generic @dfn{translator} mechanism
8339 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8340 typical example is encryption device mapping: all writes to the mapped
8341 device are encrypted, and all reads are deciphered, transparently.
8342 Guix extends this notion by considering any device or set of devices that
8343 are @dfn{transformed} in some way to create a new device; for instance,
8344 RAID devices are obtained by @dfn{assembling} several other devices, such
8345 as hard disks or partitions, into a new one that behaves as one partition.
8346 Other examples, not yet implemented, are LVM logical volumes.
8348 Mapped devices are declared using the @code{mapped-device} form,
8349 defined as follows; for examples, see below.
8351 @deftp {Data Type} mapped-device
8352 Objects of this type represent device mappings that will be made when
8353 the system boots up.
8357 This is either a string specifying the name of the block device to be mapped,
8358 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8359 need to be assembled for creating a new one.
8362 This string specifies the name of the resulting mapped device. For
8363 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8364 specifying @code{"my-partition"} leads to the creation of
8365 the @code{"/dev/mapper/my-partition"} device.
8366 For RAID devices of type @code{raid-device-mapping}, the full device name
8367 such as @code{"/dev/md0"} needs to be given.
8370 This must be a @code{mapped-device-kind} object, which specifies how
8371 @var{source} is mapped to @var{target}.
8375 @defvr {Scheme Variable} luks-device-mapping
8376 This defines LUKS block device encryption using the @command{cryptsetup}
8377 command from the package with the same name. It relies on the
8378 @code{dm-crypt} Linux kernel module.
8381 @defvr {Scheme Variable} raid-device-mapping
8382 This defines a RAID device, which is assembled using the @code{mdadm}
8383 command from the package with the same name. It requires a Linux kernel
8384 module for the appropriate RAID level to be loaded, such as @code{raid456}
8385 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8388 @cindex disk encryption
8390 The following example specifies a mapping from @file{/dev/sda3} to
8391 @file{/dev/mapper/home} using LUKS---the
8392 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8393 standard mechanism for disk encryption.
8394 The @file{/dev/mapper/home}
8395 device can then be used as the @code{device} of a @code{file-system}
8396 declaration (@pxref{File Systems}).
8400 (source "/dev/sda3")
8402 (type luks-device-mapping))
8405 Alternatively, to become independent of device numbering, one may obtain
8406 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8410 cryptsetup luksUUID /dev/sda3
8413 and use it as follows:
8417 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8419 (type luks-device-mapping))
8422 @cindex swap encryption
8423 It is also desirable to encrypt swap space, since swap space may contain
8424 sensitive data. One way to accomplish that is to use a swap file in a
8425 file system on a device mapped via LUKS encryption. In this way, the
8426 swap file is encrypted because the entire device is encrypted.
8427 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8429 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8430 may be declared as follows:
8434 (source (list "/dev/sda1" "/dev/sdb1"))
8436 (type raid-device-mapping))
8439 The @file{/dev/md0} device can then be used as the @code{device} of a
8440 @code{file-system} declaration (@pxref{File Systems}).
8441 Note that the RAID level need not be given; it is chosen during the
8442 initial creation and formatting of the RAID device and is determined
8443 automatically later.
8447 @subsection User Accounts
8451 @cindex user accounts
8452 User accounts and groups are entirely managed through the
8453 @code{operating-system} declaration. They are specified with the
8454 @code{user-account} and @code{user-group} forms:
8460 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8462 "video" ;video devices such as webcams
8463 "cdrom")) ;the good ol' CD-ROM
8464 (comment "Bob's sister")
8465 (home-directory "/home/alice"))
8468 When booting or upon completion of @command{guix system reconfigure},
8469 the system ensures that only the user accounts and groups specified in
8470 the @code{operating-system} declaration exist, and with the specified
8471 properties. Thus, account or group creations or modifications made by
8472 directly invoking commands such as @command{useradd} are lost upon
8473 reconfiguration or reboot. This ensures that the system remains exactly
8476 @deftp {Data Type} user-account
8477 Objects of this type represent user accounts. The following members may
8482 The name of the user account.
8486 This is the name (a string) or identifier (a number) of the user group
8487 this account belongs to.
8489 @item @code{supplementary-groups} (default: @code{'()})
8490 Optionally, this can be defined as a list of group names that this
8493 @item @code{uid} (default: @code{#f})
8494 This is the user ID for this account (a number), or @code{#f}. In the
8495 latter case, a number is automatically chosen by the system when the
8498 @item @code{comment} (default: @code{""})
8499 A comment about the account, such as the account owner's full name.
8501 @item @code{home-directory}
8502 This is the name of the home directory for the account.
8504 @item @code{create-home-directory?} (default: @code{#t})
8505 Indicates whether the home directory of this account should be created
8506 if it does not exist yet.
8508 @item @code{shell} (default: Bash)
8509 This is a G-expression denoting the file name of a program to be used as
8510 the shell (@pxref{G-Expressions}).
8512 @item @code{system?} (default: @code{#f})
8513 This Boolean value indicates whether the account is a ``system''
8514 account. System accounts are sometimes treated specially; for instance,
8515 graphical login managers do not list them.
8517 @anchor{user-account-password}
8518 @item @code{password} (default: @code{#f})
8519 You would normally leave this field to @code{#f}, initialize user
8520 passwords as @code{root} with the @command{passwd} command, and then let
8521 users change it with @command{passwd}. Passwords set with
8522 @command{passwd} are of course preserved across reboot and
8525 If you @emph{do} want to have a preset password for an account, then
8526 this field must contain the encrypted password, as a string.
8527 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8528 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8529 Manual}, for information on Guile's @code{crypt} procedure.
8535 User group declarations are even simpler:
8538 (user-group (name "students"))
8541 @deftp {Data Type} user-group
8542 This type is for, well, user groups. There are just a few fields:
8546 The name of the group.
8548 @item @code{id} (default: @code{#f})
8549 The group identifier (a number). If @code{#f}, a new number is
8550 automatically allocated when the group is created.
8552 @item @code{system?} (default: @code{#f})
8553 This Boolean value indicates whether the group is a ``system'' group.
8554 System groups have low numerical IDs.
8556 @item @code{password} (default: @code{#f})
8557 What, user groups can have a password? Well, apparently yes. Unless
8558 @code{#f}, this field specifies the password of the group.
8563 For convenience, a variable lists all the basic user groups one may
8566 @defvr {Scheme Variable} %base-groups
8567 This is the list of basic user groups that users and/or packages expect
8568 to be present on the system. This includes groups such as ``root'',
8569 ``wheel'', and ``users'', as well as groups used to control access to
8570 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8573 @defvr {Scheme Variable} %base-user-accounts
8574 This is the list of basic system accounts that programs may expect to
8575 find on a GNU/Linux system, such as the ``nobody'' account.
8577 Note that the ``root'' account is not included here. It is a
8578 special-case and is automatically added whether or not it is specified.
8585 A @dfn{locale} defines cultural conventions for a particular language
8586 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8587 Reference Manual}). Each locale has a name that typically has the form
8588 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8589 @code{fr_LU.utf8} designates the locale for the French language, with
8590 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8592 @cindex locale definition
8593 Usually, you will want to specify the default locale for the machine
8594 using the @code{locale} field of the @code{operating-system} declaration
8595 (@pxref{operating-system Reference, @code{locale}}).
8597 The selected locale is automatically added to the @dfn{locale
8598 definitions} known to the system if needed, with its codeset inferred
8599 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8600 @code{UTF-8} codeset. Additional locale definitions can be specified in
8601 the @code{locale-definitions} slot of @code{operating-system}---this is
8602 useful, for instance, if the codeset could not be inferred from the
8603 locale name. The default set of locale definitions includes some widely
8604 used locales, but not all the available locales, in order to save space.
8606 For instance, to add the North Frisian locale for Germany, the value of
8610 (cons (locale-definition
8611 (name "fy_DE.utf8") (source "fy_DE"))
8612 %default-locale-definitions)
8615 Likewise, to save space, one might want @code{locale-definitions} to
8616 list only the locales that are actually used, as in:
8619 (list (locale-definition
8620 (name "ja_JP.eucjp") (source "ja_JP")
8621 (charset "EUC-JP")))
8625 The compiled locale definitions are available at
8626 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8627 version, which is the default location where the GNU@tie{}libc provided
8628 by Guix looks for locale data. This can be overridden using the
8629 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8630 @code{LOCPATH} and locale packages}).
8632 The @code{locale-definition} form is provided by the @code{(gnu system
8633 locale)} module. Details are given below.
8635 @deftp {Data Type} locale-definition
8636 This is the data type of a locale definition.
8641 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8642 Reference Manual}, for more information on locale names.
8645 The name of the source for that locale. This is typically the
8646 @code{@var{language}_@var{territory}} part of the locale name.
8648 @item @code{charset} (default: @code{"UTF-8"})
8649 The ``character set'' or ``code set'' for that locale,
8650 @uref{http://www.iana.org/assignments/character-sets, as defined by
8656 @defvr {Scheme Variable} %default-locale-definitions
8657 A list of commonly used UTF-8 locales, used as the default
8658 value of the @code{locale-definitions} field of @code{operating-system}
8662 @cindex normalized codeset in locale names
8663 These locale definitions use the @dfn{normalized codeset} for the part
8664 that follows the dot in the name (@pxref{Using gettextized software,
8665 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8666 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8670 @subsubsection Locale Data Compatibility Considerations
8672 @cindex incompatibility, of locale data
8673 @code{operating-system} declarations provide a @code{locale-libcs} field
8674 to specify the GNU@tie{}libc packages that are used to compile locale
8675 declarations (@pxref{operating-system Reference}). ``Why would I
8676 care?'', you may ask. Well, it turns out that the binary format of
8677 locale data is occasionally incompatible from one libc version to
8680 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8681 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8682 For instance, a program linked against libc version 2.21 is unable to
8683 read locale data produced with libc 2.22; worse, that program
8684 @emph{aborts} instead of simply ignoring the incompatible locale
8685 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8686 the incompatible locale data, which is already an improvement.}.
8687 Similarly, a program linked against libc 2.22 can read most, but not
8688 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8689 data is incompatible); thus calls to @code{setlocale} may fail, but
8690 programs will not abort.
8692 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8693 choose whether and when to upgrade software in their profiles, and might
8694 be using a libc version different from the one the system administrator
8695 used to build the system-wide locale data.
8697 Fortunately, unprivileged users can also install their own locale data
8698 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8699 @code{GUIX_LOCPATH} and locale packages}).
8701 Still, it is best if the system-wide locale data at
8702 @file{/run/current-system/locale} is built for all the libc versions
8703 actually in use on the system, so that all the programs can access
8704 it---this is especially crucial on a multi-user system. To do that, the
8705 administrator can specify several libc packages in the
8706 @code{locale-libcs} field of @code{operating-system}:
8709 (use-package-modules base)
8713 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8716 This example would lead to a system containing locale definitions for
8717 both libc 2.21 and the current version of libc in
8718 @file{/run/current-system/locale}.
8722 @subsection Services
8724 @cindex system services
8725 An important part of preparing an @code{operating-system} declaration is
8726 listing @dfn{system services} and their configuration (@pxref{Using the
8727 Configuration System}). System services are typically daemons launched
8728 when the system boots, or other actions needed at that time---e.g.,
8729 configuring network access.
8731 GuixSD has a broad definition of ``service'' (@pxref{Service
8732 Composition}), but many services are managed by the GNU@tie{}Shepherd
8733 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8734 command allows you to list the available services, show their status,
8735 start and stop them, or do other specific operations (@pxref{Jump
8736 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8742 The above command, run as @code{root}, lists the currently defined
8743 services. The @command{herd doc} command shows a synopsis of the given
8748 Run libc's name service cache daemon (nscd).
8751 The @command{start}, @command{stop}, and @command{restart} sub-commands
8752 have the effect you would expect. For instance, the commands below stop
8753 the nscd service and restart the Xorg display server:
8757 Service nscd has been stopped.
8758 # herd restart xorg-server
8759 Service xorg-server has been stopped.
8760 Service xorg-server has been started.
8763 The following sections document the available services, starting with
8764 the core services, that may be used in an @code{operating-system}
8768 * Base Services:: Essential system services.
8769 * Scheduled Job Execution:: The mcron service.
8770 * Log Rotation:: The rottlog service.
8771 * Networking Services:: Network setup, SSH daemon, etc.
8772 * X Window:: Graphical display.
8773 * Printing Services:: Local and remote printer support.
8774 * Desktop Services:: D-Bus and desktop services.
8775 * Database Services:: SQL databases.
8776 * Mail Services:: IMAP, POP3, SMTP, and all that.
8777 * Messaging Services:: Messaging services.
8778 * Kerberos Services:: Kerberos services.
8779 * Web Services:: Web servers.
8780 * DNS Services:: DNS daemons.
8781 * VPN Services:: VPN daemons.
8782 * Network File System:: NFS related services.
8783 * Continuous Integration:: The Cuirass service.
8784 * Power management Services:: The TLP tool.
8785 * Miscellaneous Services:: Other services.
8789 @subsubsection Base Services
8791 The @code{(gnu services base)} module provides definitions for the basic
8792 services that one expects from the system. The services exported by
8793 this module are listed below.
8795 @defvr {Scheme Variable} %base-services
8796 This variable contains a list of basic services (@pxref{Service Types
8797 and Services}, for more information on service objects) one would
8798 expect from the system: a login service (mingetty) on each tty, syslogd,
8799 the libc name service cache daemon (nscd), the udev device manager, and
8802 This is the default value of the @code{services} field of
8803 @code{operating-system} declarations. Usually, when customizing a
8804 system, you will want to append services to @var{%base-services}, like
8808 (cons* (avahi-service) (lsh-service) %base-services)
8812 @defvr {Scheme Variable} special-files-service-type
8813 This is the service that sets up ``special files'' such as
8814 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
8816 The value associated with @code{special-files-service-type} services
8817 must be a list of tuples where the first element is the ``special file''
8818 and the second element is its target. By default it is:
8820 @cindex @file{/bin/sh}
8821 @cindex @file{sh}, in @file{/bin}
8823 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
8826 @cindex @file{/usr/bin/env}
8827 @cindex @file{env}, in @file{/usr/bin}
8828 If you want to add, say, @code{/usr/bin/env} to your system, you can
8832 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
8833 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
8836 Since this is part of @code{%base-services}, you can use
8837 @code{modify-services} to customize the set of special files
8838 (@pxref{Service Reference, @code{modify-services}}). But the simple way
8839 to add a special file is @i{via} the @code{extra-special-file} procedure
8843 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
8844 Use @var{target} as the ``special file'' @var{file}.
8846 For example, adding the following lines to the @code{services} field of
8847 your operating system declaration leads to a @file{/usr/bin/env}
8851 (extra-special-file "/usr/bin/env"
8852 (file-append coreutils "/bin/env"))
8856 @deffn {Scheme Procedure} host-name-service @var{name}
8857 Return a service that sets the host name to @var{name}.
8860 @deffn {Scheme Procedure} login-service @var{config}
8861 Return a service to run login according to @var{config}, a
8862 @code{<login-configuration>} object, which specifies the message of the day,
8866 @deftp {Data Type} login-configuration
8867 This is the data type representing the configuration of login.
8872 @cindex message of the day
8873 A file-like object containing the ``message of the day''.
8875 @item @code{allow-empty-passwords?} (default: @code{#t})
8876 Allow empty passwords by default so that first-time users can log in when
8877 the 'root' account has just been created.
8882 @deffn {Scheme Procedure} mingetty-service @var{config}
8883 Return a service to run mingetty according to @var{config}, a
8884 @code{<mingetty-configuration>} object, which specifies the tty to run, among
8888 @deftp {Data Type} mingetty-configuration
8889 This is the data type representing the configuration of Mingetty, which
8890 provides the default implementation of virtual console log-in.
8895 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
8897 @item @code{auto-login} (default: @code{#f})
8898 When true, this field must be a string denoting the user name under
8899 which the system automatically logs in. When it is @code{#f}, a
8900 user name and password must be entered to log in.
8902 @item @code{login-program} (default: @code{#f})
8903 This must be either @code{#f}, in which case the default log-in program
8904 is used (@command{login} from the Shadow tool suite), or a gexp denoting
8905 the name of the log-in program.
8907 @item @code{login-pause?} (default: @code{#f})
8908 When set to @code{#t} in conjunction with @var{auto-login}, the user
8909 will have to press a key before the log-in shell is launched.
8911 @item @code{mingetty} (default: @var{mingetty})
8912 The Mingetty package to use.
8917 @deffn {Scheme Procedure} agetty-service @var{config}
8918 Return a service to run agetty according to @var{config}, an
8919 @code{<agetty-configuration>} object, which specifies the tty to run,
8923 @deftp {Data Type} agetty-configuration
8924 This is the data type representing the configuration of agetty, which
8925 implements virtual and serial console log-in. See the @code{agetty(8)}
8926 man page for more information.
8931 The name of the console this agetty runs on, as a string---e.g.,
8932 @code{"ttyS0"}. This argument is mandatory.
8934 @item @code{baud-rate} (default: @code{#f})
8935 A string containing a comma-separated list of one or more baud rates, in
8938 @item @code{term} (default: @code{#f})
8939 A string containing the value used for the @code{TERM} environment
8942 @item @code{eight-bits?} (default: @code{#f})
8943 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
8946 @item @code{auto-login} (default: @code{#f})
8947 When passed a login name, as a string, the specified user will be logged
8948 in automatically without prompting for their login name or password.
8950 @item @code{no-reset?} (default: @code{#f})
8951 When @code{#t}, don't reset terminal cflags (control modes).
8953 @item @code{host} (default: @code{#f})
8954 This accepts a string containing the "login_host", which will be written
8955 into the @file{/var/run/utmpx} file.
8957 @item @code{remote?} (default: @code{#f})
8958 When set to @code{#t} in conjunction with @var{host}, this will add an
8959 @code{-r} fakehost option to the command line of the login program
8960 specified in @var{login-program}.
8962 @item @code{flow-control?} (default: @code{#f})
8963 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
8965 @item @code{no-issue?} (default: @code{#f})
8966 When set to @code{#t}, the contents of the @file{/etc/issue} file will
8967 not be displayed before presenting the login prompt.
8969 @item @code{init-string} (default: @code{#f})
8970 This accepts a string that will be sent to the tty or modem before
8971 sending anything else. It can be used to initialize a modem.
8973 @item @code{no-clear?} (default: @code{#f})
8974 When set to @code{#t}, agetty will not clear the screen before showing
8977 @item @code{login-program} (default: (file-append shadow "/bin/login"))
8978 This must be either a gexp denoting the name of a log-in program, or
8979 unset, in which case the default value is the @command{login} from the
8982 @item @code{local-line} (default: @code{#f})
8983 Control the CLOCAL line flag. This accepts one of three symbols as
8984 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
8985 the default value chosen by agetty is @code{'auto}.
8987 @item @code{extract-baud?} (default: @code{#f})
8988 When set to @code{#t}, instruct agetty to try to extract the baud rate
8989 from the status messages produced by certain types of modems.
8991 @item @code{skip-login?} (default: @code{#f})
8992 When set to @code{#t}, do not prompt the user for a login name. This
8993 can be used with @var{login-program} field to use non-standard login
8996 @item @code{no-newline?} (default: @code{#f})
8997 When set to @code{#t}, do not print a newline before printing the
8998 @file{/etc/issue} file.
9000 @c Is this dangerous only when used with login-program, or always?
9001 @item @code{login-options} (default: @code{#f})
9002 This option accepts a string containing options that are passed to the
9003 login program. When used with the @var{login-program}, be aware that a
9004 malicious user could try to enter a login name containing embedded
9005 options that could be parsed by the login program.
9007 @item @code{login-pause} (default: @code{#f})
9008 When set to @code{#t}, wait for any key before showing the login prompt.
9009 This can be used in conjunction with @var{auto-login} to save memory by
9010 lazily spawning shells.
9012 @item @code{chroot} (default: @code{#f})
9013 Change root to the specified directory. This option accepts a directory
9016 @item @code{hangup?} (default: @code{#f})
9017 Use the Linux system call @code{vhangup} to do a virtual hangup of the
9020 @item @code{keep-baud?} (default: @code{#f})
9021 When set to @code{#t}, try to keep the existing baud rate. The baud
9022 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
9025 @item @code{timeout} (default: @code{#f})
9026 When set to an integer value, terminate if no user name could be read
9027 within @var{timeout} seconds.
9029 @item @code{detect-case?} (default: @code{#f})
9030 When set to @code{#t}, turn on support for detecting an uppercase-only
9031 terminal. This setting will detect a login name containing only
9032 uppercase letters as indicating an uppercase-only terminal and turn on
9033 some upper-to-lower case conversions. Note that this will not support
9036 @item @code{wait-cr?} (default: @code{#f})
9037 When set to @code{#t}, wait for the user or modem to send a
9038 carriage-return or linefeed character before displaying
9039 @file{/etc/issue} or login prompt. This is typically used with the
9040 @var{init-string} option.
9042 @item @code{no-hints?} (default: @code{#f})
9043 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
9046 @item @code{no-hostname?} (default: @code{#f})
9047 By default, the hostname is printed. When this option is set to
9048 @code{#t}, no hostname will be shown at all.
9050 @item @code{long-hostname?} (default: @code{#f})
9051 By default, the hostname is only printed until the first dot. When this
9052 option is set to @code{#t}, the fully qualified hostname by
9053 @code{gethostname} or @code{getaddrinfo} is shown.
9055 @item @code{erase-characters} (default: @code{#f})
9056 This option accepts a string of additional characters that should be
9057 interpreted as backspace when the user types their login name.
9059 @item @code{kill-characters} (default: @code{#f})
9060 This option accepts a string that should be interpreted to mean "ignore
9061 all previous characters" (also called a "kill" character) when the types
9064 @item @code{chdir} (default: @code{#f})
9065 This option accepts, as a string, a directory path that will be changed
9068 @item @code{delay} (default: @code{#f})
9069 This options accepts, as an integer, the number of seconds to sleep
9070 before opening the tty and displaying the login prompt.
9072 @item @code{nice} (default: @code{#f})
9073 This option accepts, as an integer, the nice value with which to run the
9074 @command{login} program.
9076 @item @code{extra-options} (default: @code{'()})
9077 This option provides an "escape hatch" for the user to provide arbitrary
9078 command-line arguments to @command{agetty} as a list of strings.
9083 @deffn {Scheme Procedure} kmscon-service-type @var{config}
9084 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
9085 according to @var{config}, a @code{<kmscon-configuration>} object, which
9086 specifies the tty to run, among other things.
9089 @deftp {Data Type} kmscon-configuration
9090 This is the data type representing the configuration of Kmscon, which
9091 implements virtual console log-in.
9095 @item @code{virtual-terminal}
9096 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
9098 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
9099 A gexp denoting the name of the log-in program. The default log-in program is
9100 @command{login} from the Shadow tool suite.
9102 @item @code{login-arguments} (default: @code{'("-p")})
9103 A list of arguments to pass to @command{login}.
9105 @item @code{hardware-acceleration?} (default: #f)
9106 Whether to use hardware acceleration.
9108 @item @code{kmscon} (default: @var{kmscon})
9109 The Kmscon package to use.
9114 @cindex name service cache daemon
9116 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
9117 [#:name-services '()]
9118 Return a service that runs the libc name service cache daemon (nscd) with the
9119 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
9120 Service Switch}, for an example.
9123 @defvr {Scheme Variable} %nscd-default-configuration
9124 This is the default @code{<nscd-configuration>} value (see below) used
9125 by @code{nscd-service}. It uses the caches defined by
9126 @var{%nscd-default-caches}; see below.
9129 @deftp {Data Type} nscd-configuration
9130 This is the data type representing the name service cache daemon (nscd)
9135 @item @code{name-services} (default: @code{'()})
9136 List of packages denoting @dfn{name services} that must be visible to
9137 the nscd---e.g., @code{(list @var{nss-mdns})}.
9139 @item @code{glibc} (default: @var{glibc})
9140 Package object denoting the GNU C Library providing the @command{nscd}
9143 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
9144 Name of the nscd log file. This is where debugging output goes when
9145 @code{debug-level} is strictly positive.
9147 @item @code{debug-level} (default: @code{0})
9148 Integer denoting the debugging levels. Higher numbers mean that more
9149 debugging output is logged.
9151 @item @code{caches} (default: @var{%nscd-default-caches})
9152 List of @code{<nscd-cache>} objects denoting things to be cached; see
9158 @deftp {Data Type} nscd-cache
9159 Data type representing a cache database of nscd and its parameters.
9163 @item @code{database}
9164 This is a symbol representing the name of the database to be cached.
9165 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
9166 @code{services}, which designate the corresponding NSS database
9167 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
9169 @item @code{positive-time-to-live}
9170 @itemx @code{negative-time-to-live} (default: @code{20})
9171 A number representing the number of seconds during which a positive or
9172 negative lookup result remains in cache.
9174 @item @code{check-files?} (default: @code{#t})
9175 Whether to check for updates of the files corresponding to
9178 For instance, when @var{database} is @code{hosts}, setting this flag
9179 instructs nscd to check for updates in @file{/etc/hosts} and to take
9182 @item @code{persistent?} (default: @code{#t})
9183 Whether the cache should be stored persistently on disk.
9185 @item @code{shared?} (default: @code{#t})
9186 Whether the cache should be shared among users.
9188 @item @code{max-database-size} (default: 32@tie{}MiB)
9189 Maximum size in bytes of the database cache.
9191 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9192 @c settings, so leave them out.
9197 @defvr {Scheme Variable} %nscd-default-caches
9198 List of @code{<nscd-cache>} objects used by default by
9199 @code{nscd-configuration} (see above).
9201 It enables persistent and aggressive caching of service and host name
9202 lookups. The latter provides better host name lookup performance,
9203 resilience in the face of unreliable name servers, and also better
9204 privacy---often the result of host name lookups is in local cache, so
9205 external name servers do not even need to be queried.
9208 @anchor{syslog-configuration-type}
9211 @deftp {Data Type} syslog-configuration
9212 This data type represents the configuration of the syslog daemon.
9215 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9216 The syslog daemon to use.
9218 @item @code{config-file} (default: @code{%default-syslog.conf})
9219 The syslog configuration file to use.
9224 @anchor{syslog-service}
9226 @deffn {Scheme Procedure} syslog-service @var{config}
9227 Return a service that runs a syslog daemon according to @var{config}.
9229 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9230 information on the configuration file syntax.
9233 @anchor{guix-configuration-type}
9234 @deftp {Data Type} guix-configuration
9235 This data type represents the configuration of the Guix build daemon.
9236 @xref{Invoking guix-daemon}, for more information.
9239 @item @code{guix} (default: @var{guix})
9240 The Guix package to use.
9242 @item @code{build-group} (default: @code{"guixbuild"})
9243 Name of the group for build user accounts.
9245 @item @code{build-accounts} (default: @code{10})
9246 Number of build user accounts to create.
9248 @item @code{authorize-key?} (default: @code{#t})
9249 @cindex substitutes, authorization thereof
9250 Whether to authorize the substitute keys listed in
9251 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9252 (@pxref{Substitutes}).
9254 @vindex %default-authorized-guix-keys
9255 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9256 The list of authorized key files for archive imports, as a list of
9257 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9258 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9260 @item @code{use-substitutes?} (default: @code{#t})
9261 Whether to use substitutes.
9263 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9264 The list of URLs where to look for substitutes by default.
9266 @item @code{max-silent-time} (default: @code{0})
9267 @itemx @code{timeout} (default: @code{0})
9268 The number of seconds of silence and the number of seconds of activity,
9269 respectively, after which a build process times out. A value of zero
9270 disables the timeout.
9272 @item @code{extra-options} (default: @code{'()})
9273 List of extra command-line options for @command{guix-daemon}.
9275 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9276 File where @command{guix-daemon}'s standard output and standard error
9279 @item @code{lsof} (default: @var{lsof})
9280 The lsof package to use.
9282 @item @code{http-proxy} (default: @code{#f})
9283 The HTTP proxy used for downloading fixed-output derivations and
9286 @item @code{tmpdir} (default: @code{#f})
9287 A directory path where the @command{guix-daemon} will perform builds.
9292 @deffn {Scheme Procedure} guix-service @var{config}
9293 Return a service that runs the Guix build daemon according to
9297 @deffn {Scheme Procedure} udev-service [#:udev udev]
9298 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9301 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9302 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9306 @defvr {Scheme Variable} %random-seed-file
9307 This is the name of the file where some random bytes are saved by
9308 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9309 It defaults to @file{/var/lib/random-seed}.
9314 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9315 @cindex keyboard layout
9316 Return a service to load console keymaps from @var{files} using
9317 @command{loadkeys} command. Most likely, you want to load some default
9318 keymap, which can be done like this:
9321 (console-keymap-service "dvorak")
9324 Or, for example, for a Swedish keyboard, you may need to combine
9325 the following keymaps:
9327 (console-keymap-service "se-lat6" "se-fi-lat6")
9330 Also you can specify a full file name (or file names) of your keymap(s).
9331 See @code{man loadkeys} for details.
9337 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9339 Run @var{gpm}, the general-purpose mouse daemon, with the given
9340 command-line @var{options}. GPM allows users to use the mouse in the console,
9341 notably to select, copy, and paste text. The default value of @var{options}
9342 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9344 This service is not part of @var{%base-services}.
9347 @anchor{guix-publish-service-type}
9348 @deffn {Scheme Variable} guix-publish-service-type
9349 This is the service type for @command{guix publish} (@pxref{Invoking
9350 guix publish}). Its value must be a @code{guix-configuration}
9351 object, as described below.
9353 This assumes that @file{/etc/guix} already contains a signing key pair as
9354 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9355 archive}). If that is not the case, the service will fail to start.
9358 @deftp {Data Type} guix-publish-configuration
9359 Data type representing the configuration of the @code{guix publish}
9363 @item @code{guix} (default: @code{guix})
9364 The Guix package to use.
9366 @item @code{port} (default: @code{80})
9367 The TCP port to listen for connections.
9369 @item @code{host} (default: @code{"localhost"})
9370 The host (and thus, network interface) to listen to. Use
9371 @code{"0.0.0.0"} to listen on all the network interfaces.
9373 @item @code{compression-level} (default: @code{3})
9374 The gzip compression level at which substitutes are compressed. Use
9375 @code{0} to disable compression altogether, and @code{9} to get the best
9376 compression ratio at the expense of increased CPU usage.
9378 @item @code{nar-path} (default: @code{"nar"})
9379 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9380 publish, @code{--nar-path}}, for details.
9382 @item @code{cache} (default: @code{#f})
9383 When it is @code{#f}, disable caching and instead generate archives on
9384 demand. Otherwise, this should be the name of a directory---e.g.,
9385 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
9386 archives and meta-data ready to be sent. @xref{Invoking guix publish,
9387 @option{--cache}}, for more information on the tradeoffs involved.
9389 @item @code{workers} (default: @code{#f})
9390 When it is an integer, this is the number of worker threads used for
9391 caching; when @code{#f}, the number of processors is used.
9392 @xref{Invoking guix publish, @option{--workers}}, for more information.
9394 @item @code{ttl} (default: @code{#f})
9395 When it is an integer, this denotes the @dfn{time-to-live} of the
9396 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
9401 @anchor{rngd-service}
9402 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9403 [#:device "/dev/hwrng"]
9404 Return a service that runs the @command{rngd} program from @var{rng-tools}
9405 to add @var{device} to the kernel's entropy pool. The service will fail if
9406 @var{device} does not exist.
9409 @anchor{pam-limits-service}
9410 @cindex session limits
9413 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9415 Return a service that installs a configuration file for the
9416 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9417 @code{pam_limits} module}. The procedure optionally takes a list of
9418 @code{pam-limits-entry} values, which can be used to specify
9419 @code{ulimit} limits and nice priority limits to user sessions.
9421 The following limits definition sets two hard and soft limits for all
9422 login sessions of users in the @code{realtime} group:
9427 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9428 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9431 The first entry increases the maximum realtime priority for
9432 non-privileged processes; the second entry lifts any restriction of the
9433 maximum address space that can be locked in memory. These settings are
9434 commonly used for real-time audio systems.
9437 @node Scheduled Job Execution
9438 @subsubsection Scheduled Job Execution
9442 @cindex scheduling jobs
9443 The @code{(gnu services mcron)} module provides an interface to
9444 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9445 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9446 Unix @command{cron} daemon; the main difference is that it is
9447 implemented in Guile Scheme, which provides a lot of flexibility when
9448 specifying the scheduling of jobs and their actions.
9450 The example below defines an operating system that runs the
9451 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9452 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9453 well as the @command{mkid} command on behalf of an unprivileged user
9454 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9455 gexps to introduce job definitions that are passed to mcron
9456 (@pxref{G-Expressions}).
9459 (use-modules (guix) (gnu) (gnu services mcron))
9460 (use-package-modules base idutils)
9462 (define updatedb-job
9463 ;; Run 'updatedb' at 3AM every day. Here we write the
9464 ;; job's action as a Scheme procedure.
9465 #~(job '(next-hour '(3))
9467 (execl (string-append #$findutils "/bin/updatedb")
9469 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9471 (define garbage-collector-job
9472 ;; Collect garbage 5 minutes after midnight every day.
9473 ;; The job's action is a shell command.
9474 #~(job "5 0 * * *" ;Vixie cron syntax
9478 ;; Update the index database as user "charlie" at 12:15PM
9479 ;; and 19:15PM. This runs from the user's home directory.
9480 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9481 (string-append #$idutils "/bin/mkid src")
9486 (services (cons (mcron-service (list garbage-collector-job
9492 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9493 for more information on mcron job specifications. Below is the
9494 reference of the mcron service.
9496 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9497 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9498 list of gexps denoting mcron job specifications.
9500 This is a shorthand for:
9502 (service mcron-service-type
9503 (mcron-configuration (mcron mcron) (jobs jobs)))
9507 @defvr {Scheme Variable} mcron-service-type
9508 This is the type of the @code{mcron} service, whose value is an
9509 @code{mcron-configuration} object.
9511 This service type can be the target of a service extension that provides
9512 it additional job specifications (@pxref{Service Composition}). In
9513 other words, it is possible to define services that provide additional
9517 @deftp {Data Type} mcron-configuration
9518 Data type representing the configuration of mcron.
9521 @item @code{mcron} (default: @var{mcron2})
9522 The mcron package to use.
9525 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9526 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9527 specifications,, mcron, GNU@tie{}mcron}).
9533 @subsubsection Log Rotation
9536 @cindex log rotation
9538 Log files such as those found in @file{/var/log} tend to grow endlessly,
9539 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9540 their contents in separate files, possibly compressed. The @code{(gnu
9541 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9542 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9544 The example below defines an operating system that provides log rotation
9545 with the default settings.
9548 (use-modules (guix) (gnu))
9549 (use-service-modules admin mcron)
9550 (use-package-modules base idutils)
9554 (services (cons* (mcron-service)
9555 (service rottlog-service-type)
9559 @defvr {Scheme Variable} rottlog-service-type
9560 This is the type of the Rottlog service, whose value is a
9561 @code{rottlog-configuration} object.
9563 This service type can define mcron jobs (@pxref{Scheduled Job
9564 Execution}) to run the rottlog service.
9567 @deftp {Data Type} rottlog-configuration
9568 Data type representing the configuration of rottlog.
9571 @item @code{rottlog} (default: @code{rottlog})
9572 The Rottlog package to use.
9574 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9575 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9576 rottlog, GNU Rot[t]log Manual}).
9578 @item @code{periodic-rotations} (default: @code{`(("weekly" %default-rotations))})
9579 A list of Rottlog period-name/period-config tuples.
9581 For example, taking an example from the Rottlog manual (@pxref{Period
9582 Related File Examples,,, rottlog, GNU Rot[t]log Manual}), a valid tuple
9586 ("daily" ,(plain-file "daily"
9588 /var/log/apache/* @{
9589 storedir apache-archives
9597 This is a list of gexps where each gexp corresponds to an mcron job
9598 specification (@pxref{Scheduled Job Execution}).
9602 @defvr {Scheme Variable} %default-rotations
9603 Specifies weekly rotation of @var{%rotated-files} and
9604 @code{"/var/log/shepherd.log"}.
9607 @defvr {Scheme Variable} %rotated-files
9608 The list of syslog-controlled files to be rotated. By default it is:
9609 @code{'("/var/log/messages" "/var/log/secure")}.
9612 @node Networking Services
9613 @subsubsection Networking Services
9615 The @code{(gnu services networking)} module provides services to configure
9616 the network interface.
9618 @cindex DHCP, networking service
9619 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9620 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9621 Protocol (DHCP) client, on all the non-loopback network interfaces.
9624 @defvr {Scheme Variable} static-networking-service-type
9625 This is the type for statically-configured network interfaces.
9626 @c TODO Document <static-networking> data structures.
9629 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9630 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9631 Return a service that starts @var{interface} with address @var{ip}. If
9632 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9633 it must be a string specifying the default network gateway.
9635 This procedure can be called several times, one for each network
9636 interface of interest. Behind the scenes what it does is extend
9637 @code{static-networking-service-type} with additional network interfaces
9644 @cindex network management
9645 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9646 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9647 management daemon that aims to simplify wired and wireless networking.
9649 This service adds the @var{wicd} package to the global profile, providing
9650 several commands to interact with the daemon and configure networking:
9651 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
9652 and @command{wicd-curses} user interfaces.
9655 @cindex NetworkManager
9657 @defvr {Scheme Variable} network-manager-service-type
9658 This is the service type for the
9659 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
9660 service. The value for this service type is a
9661 @code{network-manager-configuration} record.
9664 @deftp {Data Type} network-manager-configuration
9665 Data type representing the configuration of NetworkManager.
9668 @item @code{network-manager} (default: @code{network-manager})
9669 The NetworkManager package to use.
9671 @item @code{dns} (default: @code{"default"})
9672 Processing mode for DNS, which affects how NetworkManager uses the
9673 @code{resolv.conf} configuration file.
9677 NetworkManager will update @code{resolv.conf} to reflect the nameservers
9678 provided by currently active connections.
9681 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
9682 using a "split DNS" configuration if you are connected to a VPN, and
9683 then update @code{resolv.conf} to point to the local nameserver.
9686 NetworkManager will not modify @code{resolv.conf}.
9693 @deffn {Scheme Variable} connman-service-type
9694 This is the service type to run @url{https://01.org/connman,Connman},
9695 a network connection manager.
9697 Its value must be an
9698 @code{connman-configuration} record as in this example:
9701 (service connman-service-type
9702 (connman-configuration
9706 See below for details about @code{connman-configuration}.
9709 @deftp {Data Type} connman-configuration
9710 Data Type representing the configuration of connman.
9713 @item @code{connman} (default: @var{connman})
9714 The connman package to use.
9716 @item @code{disable-vpn?} (default: @code{#f})
9717 When true, enable connman's vpn plugin.
9721 @cindex WPA Supplicant
9722 @defvr {Scheme Variable} wpa-supplicant-service-type
9723 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
9724 supplicant}, an authentication daemon required to authenticate against
9725 encrypted WiFi or ethernet networks. It is configured to listen for
9728 The value of this service is the @code{wpa-supplicant} package to use.
9729 Thus, it can be instantiated like this:
9732 (use-modules (gnu services networking))
9734 (service wpa-supplicant-service-type)
9739 @cindex real time clock
9740 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
9741 [#:servers @var{%ntp-servers}] @
9742 [#:allow-large-adjustment? #f]
9743 Return a service that runs the daemon from @var{ntp}, the
9744 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
9745 keep the system clock synchronized with that of @var{servers}.
9746 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
9747 make an initial adjustment of more than 1,000 seconds.
9750 @defvr {Scheme Variable} %ntp-servers
9751 List of host names used as the default NTP servers.
9755 @deffn {Scheme variable} inetd-service-type
9756 This service runs the @command{inetd} (@pxref{inetd invocation,,,
9757 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
9758 connections on internet sockets, and lazily starts the specified server
9759 program when a connection is made on one of these sockets.
9761 The value of this service is an @code{inetd-configuration} object. The
9762 following example configures the @command{inetd} daemon to provide the
9763 built-in @command{echo} service, as well as an smtp service which
9764 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
9765 gateway @code{hostname}:
9770 (inetd-configuration
9774 (socket-type 'stream)
9781 (socket-type 'stream)
9785 (program (file-append openssh "/bin/ssh"))
9787 '("ssh" "-qT" "-i" "/path/to/ssh_key"
9788 "-W" "smtp-server:25" "user@@hostname")))))
9791 See below for more details about @code{inetd-configuration}.
9794 @deftp {Data Type} inetd-configuration
9795 Data type representing the configuration of @command{inetd}.
9798 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
9799 The @command{inetd} executable to use.
9801 @item @code{entries} (default: @code{'()})
9802 A list of @command{inetd} service entries. Each entry should be created
9803 by the @code{inetd-entry} constructor.
9807 @deftp {Data Type} inetd-entry
9808 Data type representing an entry in the @command{inetd} configuration.
9809 Each entry corresponds to a socket where @command{inetd} will listen for
9813 @item @code{node} (default: @code{#f})
9814 Optional string, a comma-separated list of local addresses
9815 @command{inetd} should use when listening for this service.
9816 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
9817 description of all options.
9819 A string, the name must correspond to an entry in @code{/etc/services}.
9820 @item @code{socket-type}
9821 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
9823 @item @code{protocol}
9824 A string, must correspond to an entry in @code{/etc/protocols}.
9825 @item @code{wait?} (default: @code{#t})
9826 Whether @command{inetd} should wait for the server to exit before
9827 listening to new service requests.
9829 A string containing the user (and, optionally, group) name of the user
9830 as whom the server should run. The group name can be specified in a
9831 suffix, separated by a colon or period, i.e. @code{"user"},
9832 @code{"user:group"} or @code{"user.group"}.
9833 @item @code{program} (default: @code{"internal"})
9834 The server program which will serve the requests, or @code{"internal"}
9835 if @command{inetd} should use a built-in service.
9836 @item @code{arguments} (default: @code{'()})
9837 A list strings or file-like objects, which are the server program's
9838 arguments, starting with the zeroth argument, i.e. the name of the
9839 program itself. For @command{inetd}'s internal services, this entry
9840 must be @code{'()} or @code{'("internal")}.
9843 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
9844 detailed discussion of each configuration field.
9848 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
9849 Return a service to run the @uref{https://torproject.org, Tor} anonymous
9852 The daemon runs as the @code{tor} unprivileged user. It is passed
9853 @var{config-file}, a file-like object, with an additional @code{User tor} line
9854 and lines for hidden services added via @code{tor-hidden-service}. Run
9855 @command{man tor} for information about the configuration file.
9858 @cindex hidden service
9859 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
9860 Define a new Tor @dfn{hidden service} called @var{name} and implementing
9861 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
9864 '((22 "127.0.0.1:22")
9865 (80 "127.0.0.1:8080"))
9868 In this example, port 22 of the hidden service is mapped to local port 22, and
9869 port 80 is mapped to local port 8080.
9871 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
9872 the @file{hostname} file contains the @code{.onion} host name for the hidden
9875 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
9876 project's documentation} for more information.
9879 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
9880 [#:interface "127.0.0.1"] [#:port 6667] @
9881 [#:extra-settings ""]
9882 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
9883 acts as a gateway between IRC and chat networks.
9885 The daemon will listen to the interface corresponding to the IP address
9886 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
9887 local clients can connect, whereas @code{0.0.0.0} means that connections can
9888 come from any networking interface.
9890 In addition, @var{extra-settings} specifies a string to append to the
9894 Furthermore, @code{(gnu services ssh)} provides the following services.
9898 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
9899 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
9900 [#:allow-empty-passwords? #f] [#:root-login? #f] @
9901 [#:syslog-output? #t] [#:x11-forwarding? #t] @
9902 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
9903 [#:public-key-authentication? #t] [#:initialize? #t]
9904 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
9905 @var{host-key} must designate a file containing the host key, and readable
9908 When @var{daemonic?} is true, @command{lshd} will detach from the
9909 controlling terminal and log its output to syslogd, unless one sets
9910 @var{syslog-output?} to false. Obviously, it also makes lsh-service
9911 depend on existence of syslogd service. When @var{pid-file?} is true,
9912 @command{lshd} writes its PID to the file called @var{pid-file}.
9914 When @var{initialize?} is true, automatically create the seed and host key
9915 upon service activation if they do not exist yet. This may take long and
9916 require interaction.
9918 When @var{initialize?} is false, it is up to the user to initialize the
9919 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
9920 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
9921 basics,,, lsh, LSH Manual}).
9923 When @var{interfaces} is empty, lshd listens for connections on all the
9924 network interfaces; otherwise, @var{interfaces} must be a list of host names
9927 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
9928 passwords, and @var{root-login?} specifies whether to accept log-ins as
9931 The other options should be self-descriptive.
9936 @deffn {Scheme Variable} openssh-service-type
9937 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
9938 shell daemon, @command{sshd}. Its value must be an
9939 @code{openssh-configuration} record as in this example:
9942 (service openssh-service-type
9943 (openssh-configuration
9944 (x11-forwarding? #t)
9945 (permit-root-login 'without-password)))
9948 See below for details about @code{openssh-configuration}.
9951 @deftp {Data Type} openssh-configuration
9952 This is the configuration record for OpenSSH's @command{sshd}.
9955 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
9956 Name of the file where @command{sshd} writes its PID.
9958 @item @code{port-number} (default: @code{22})
9959 TCP port on which @command{sshd} listens for incoming connections.
9961 @item @code{permit-root-login} (default: @code{#f})
9962 This field determines whether and when to allow logins as root. If
9963 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
9964 If it's the symbol @code{'without-password}, then root logins are
9965 permitted but not with password-based authentication.
9967 @item @code{allow-empty-passwords?} (default: @code{#f})
9968 When true, users with empty passwords may log in. When false, they may
9971 @item @code{password-authentication?} (default: @code{#t})
9972 When true, users may log in with their password. When false, they have
9973 other authentication methods.
9975 @item @code{public-key-authentication?} (default: @code{#t})
9976 When true, users may log in using public key authentication. When
9977 false, users have to use other authentication method.
9979 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
9980 This is used only by protocol version 2.
9982 @item @code{x11-forwarding?} (default: @code{#f})
9983 When true, forwarding of X11 graphical client connections is
9984 enabled---in other words, @command{ssh} options @option{-X} and
9985 @option{-Y} will work.
9987 @item @code{challenge-response-authentication?} (default: @code{#f})
9988 Specifies whether challenge response authentication is allowed (e.g. via
9991 @item @code{use-pam?} (default: @code{#t})
9992 Enables the Pluggable Authentication Module interface. If set to
9993 @code{#t}, this will enable PAM authentication using
9994 @code{challenge-response-authentication?} and
9995 @code{password-authentication?}, in addition to PAM account and session
9996 module processing for all authentication types.
9998 Because PAM challenge response authentication usually serves an
9999 equivalent role to password authentication, you should disable either
10000 @code{challenge-response-authentication?} or
10001 @code{password-authentication?}.
10003 @item @code{print-last-log?} (default: @code{#t})
10004 Specifies whether @command{sshd} should print the date and time of the
10005 last user login when a user logs in interactively.
10007 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
10008 Configures external subsystems (e.g. file transfer daemon).
10010 This is a list of two-element lists, each of which containing the
10011 subsystem name and a command (with optional arguments) to execute upon
10014 The command @command{internal-sftp} implements an in-process SFTP
10015 server. Alternately, one can specify the @command{sftp-server} command:
10017 (service openssh-service-type
10018 (openssh-configuration
10020 '(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
10025 @deffn {Scheme Procedure} dropbear-service [@var{config}]
10026 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
10027 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
10030 For example, to specify a Dropbear service listening on port 1234, add
10031 this call to the operating system's @code{services} field:
10034 (dropbear-service (dropbear-configuration
10035 (port-number 1234)))
10039 @deftp {Data Type} dropbear-configuration
10040 This data type represents the configuration of a Dropbear SSH daemon.
10043 @item @code{dropbear} (default: @var{dropbear})
10044 The Dropbear package to use.
10046 @item @code{port-number} (default: 22)
10047 The TCP port where the daemon waits for incoming connections.
10049 @item @code{syslog-output?} (default: @code{#t})
10050 Whether to enable syslog output.
10052 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
10053 File name of the daemon's PID file.
10055 @item @code{root-login?} (default: @code{#f})
10056 Whether to allow @code{root} logins.
10058 @item @code{allow-empty-passwords?} (default: @code{#f})
10059 Whether to allow empty passwords.
10061 @item @code{password-authentication?} (default: @code{#t})
10062 Whether to enable password-based authentication.
10066 @defvr {Scheme Variable} %facebook-host-aliases
10067 This variable contains a string for use in @file{/etc/hosts}
10068 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
10069 line contains a entry that maps a known server name of the Facebook
10070 on-line service---e.g., @code{www.facebook.com}---to the local
10071 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
10073 This variable is typically used in the @code{hosts-file} field of an
10074 @code{operating-system} declaration (@pxref{operating-system Reference,
10075 @file{/etc/hosts}}):
10078 (use-modules (gnu) (guix))
10081 (host-name "mymachine")
10084 ;; Create a /etc/hosts file with aliases for "localhost"
10085 ;; and "mymachine", as well as for Facebook servers.
10086 (plain-file "hosts"
10087 (string-append (local-host-aliases host-name)
10088 %facebook-host-aliases))))
10091 This mechanism can prevent programs running locally, such as Web
10092 browsers, from accessing Facebook.
10095 The @code{(gnu services avahi)} provides the following definition.
10097 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
10098 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
10099 [#:ipv6? #t] [#:wide-area? #f] @
10100 [#:domains-to-browse '()] [#:debug? #f]
10101 Return a service that runs @command{avahi-daemon}, a system-wide
10102 mDNS/DNS-SD responder that allows for service discovery and
10103 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
10104 extends the name service cache daemon (nscd) so that it can resolve
10105 @code{.local} host names using
10106 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
10107 add the @var{avahi} package to the system profile so that commands such as
10108 @command{avahi-browse} are directly usable.
10110 If @var{host-name} is different from @code{#f}, use that as the host name to
10111 publish for this machine; otherwise, use the machine's actual host name.
10113 When @var{publish?} is true, publishing of host names and services is allowed;
10114 in particular, avahi-daemon will publish the machine's host name and IP
10115 address via mDNS on the local network.
10117 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
10119 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
10123 @deffn {Scheme Variable} openvswitch-service-type
10124 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
10125 service, whose value should be an @code{openvswitch-configuration}
10129 @deftp {Data Type} openvswitch-configuration
10130 Data type representing the configuration of Open vSwitch, a multilayer
10131 virtual switch which is designed to enable massive network automation
10132 through programmatic extension.
10135 @item @code{package} (default: @var{openvswitch})
10136 Package object of the Open vSwitch.
10142 @subsubsection X Window
10145 @cindex X Window System
10146 Support for the X Window graphical display system---specifically
10147 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
10148 there is no @code{xorg-service} procedure. Instead, the X server is
10149 started by the @dfn{login manager}, currently SLiM.
10151 @deftp {Data Type} sddm-configuration
10152 This is the data type representing the sddm service configuration.
10155 @item @code{display-server} (default: "x11")
10156 Select display server to use for the greeter. Valid values are "x11"
10159 @item @code{numlock} (default: "on")
10160 Valid values are "on", "off" or "none".
10162 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
10163 Command to run when halting.
10165 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
10166 Command to run when rebooting.
10168 @item @code{theme} (default "maldives")
10169 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
10171 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
10172 Directory to look for themes.
10174 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
10175 Directory to look for faces.
10177 @item @code{default-path} (default "/run/current-system/profile/bin")
10178 Default PATH to use.
10180 @item @code{minimum-uid} (default 1000)
10181 Minimum UID to display in SDDM.
10183 @item @code{maximum-uid} (default 2000)
10184 Maximum UID to display in SDDM
10186 @item @code{remember-last-user?} (default #t)
10187 Remember last user.
10189 @item @code{remember-last-session?} (default #t)
10190 Remember last session.
10192 @item @code{hide-users} (default "")
10193 Usernames to hide from SDDM greeter.
10195 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10196 Users with shells listed will be hidden from the SDDM greeter.
10198 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10199 Script to run before starting a wayland session.
10201 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10202 Directory to look for desktop files starting wayland sessions.
10204 @item @code{xorg-server-path} (default @code{xorg-start-command})
10205 Path to xorg-server.
10207 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10210 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
10213 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
10214 Script to run after starting xorg-server.
10216 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
10217 Script to run before stopping xorg-server.
10219 @item @code{xsession-command} (default: @code{xinitr })
10220 Script to run before starting a X session.
10222 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
10223 Directory to look for desktop files starting X sessions.
10225 @item @code{minimum-vt} (default: 7)
10228 @item @code{xserver-arguments} (default "-nolisten tcp")
10229 Arguments to pass to xorg-server.
10231 @item @code{auto-login-user} (default "")
10232 User to use for auto-login.
10234 @item @code{auto-login-session} (default "")
10235 Desktop file to use for auto-login.
10237 @item @code{relogin?} (default #f)
10238 Relogin after logout.
10243 @cindex login manager
10244 @deffn {Scheme Procedure} sddm-service config
10245 Return a service that spawns the SDDM graphical login manager for config of
10246 type @code{<sddm-configuration>}.
10249 (sddm-service (sddm-configuration
10250 (auto-login-user "Alice")
10251 (auto-login-session "xfce.desktop")))
10255 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10256 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10257 [#:theme @var{%default-slim-theme}] @
10258 [#:theme-name @var{%default-slim-theme-name}]
10259 Return a service that spawns the SLiM graphical login manager, which in
10260 turn starts the X display server with @var{startx}, a command as returned by
10261 @code{xorg-start-command}.
10265 SLiM automatically looks for session types described by the @file{.desktop}
10266 files in @file{/run/current-system/profile/share/xsessions} and allows users
10267 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10268 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10269 adding them to the system-wide set of packages automatically makes them
10270 available at the log-in screen.
10272 In addition, @file{~/.xsession} files are honored. When available,
10273 @file{~/.xsession} must be an executable that starts a window manager
10274 and/or other X clients.
10276 When @var{allow-empty-passwords?} is true, allow logins with an empty
10277 password. When @var{auto-login?} is true, log in automatically as
10278 @var{default-user}.
10280 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10281 @var{theme} must be a gexp denoting the name of a directory containing the
10282 theme to use. In that case, @var{theme-name} specifies the name of the
10286 @defvr {Scheme Variable} %default-theme
10287 @defvrx {Scheme Variable} %default-theme-name
10288 The G-Expression denoting the default SLiM theme and its name.
10291 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10292 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10293 Return a derivation that builds a @var{guile} script to start the X server
10294 from @var{xorg-server}. @var{configuration-file} is the server configuration
10295 file or a derivation that builds it; when omitted, the result of
10296 @code{xorg-configuration-file} is used.
10298 Usually the X server is started by a login manager.
10301 @deffn {Scheme Procedure} xorg-configuration-file @
10302 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10303 Return a configuration file for the Xorg server containing search paths for
10304 all the common drivers.
10306 @var{drivers} must be either the empty list, in which case Xorg chooses a
10307 graphics driver automatically, or a list of driver names that will be tried in
10308 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10310 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10311 appropriate screen resolution; otherwise, it must be a list of
10312 resolutions---e.g., @code{((1024 768) (640 480))}.
10314 Last, @var{extra-config} is a list of strings or objects appended to the
10315 @code{text-file*} argument list. It is used to pass extra text to be added
10316 verbatim to the configuration file.
10319 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10320 Add @var{package}, a package for a screen-locker or screen-saver whose
10321 command is @var{program}, to the set of setuid programs and add a PAM entry
10322 for it. For example:
10325 (screen-locker-service xlockmore "xlock")
10328 makes the good ol' XlockMore usable.
10332 @node Printing Services
10333 @subsubsection Printing Services
10335 @cindex printer support with CUPS
10336 The @code{(gnu services cups)} module provides a Guix service definition
10337 for the CUPS printing service. To add printer support to a GuixSD
10338 system, add a @code{cups-service} to the operating system definition:
10340 @deffn {Scheme Variable} cups-service-type
10341 The service type for the CUPS print server. Its value should be a valid
10342 CUPS configuration (see below). To use the default settings, simply
10345 (service cups-service-type)
10349 The CUPS configuration controls the basic things about your CUPS
10350 installation: what interfaces it listens on, what to do if a print job
10351 fails, how much logging to do, and so on. To actually add a printer,
10352 you have to visit the @url{http://localhost:631} URL, or use a tool such
10353 as GNOME's printer configuration services. By default, configuring a
10354 CUPS service will generate a self-signed certificate if needed, for
10355 secure connections to the print server.
10357 Suppose you want to enable the Web interface of CUPS and also add
10358 support for HP printers @i{via} the @code{hplip} package. You can do
10359 that directly, like this (you need to use the @code{(gnu packages cups)}
10363 (service cups-service-type
10364 (cups-configuration
10365 (web-interface? #t)
10367 (list cups-filters hplip))))
10370 The available configuration parameters follow. Each parameter
10371 definition is preceded by its type; for example, @samp{string-list foo}
10372 indicates that the @code{foo} parameter should be specified as a list of
10373 strings. There is also a way to specify the configuration as a string,
10374 if you have an old @code{cupsd.conf} file that you want to port over
10375 from some other system; see the end for more details.
10377 @c The following documentation was initially generated by
10378 @c (generate-documentation) in (gnu services cups). Manually maintained
10379 @c documentation is better, so we shouldn't hesitate to edit below as
10380 @c needed. However if the change you want to make to this documentation
10381 @c can be done in an automated way, it's probably easier to change
10382 @c (generate-documentation) than to make it below and have to deal with
10383 @c the churn as CUPS updates.
10386 Available @code{cups-configuration} fields are:
10388 @deftypevr {@code{cups-configuration} parameter} package cups
10392 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10393 Drivers and other extensions to the CUPS package.
10396 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10397 Configuration of where to write logs, what directories to use for print
10398 spools, and related privileged configuration parameters.
10400 Available @code{files-configuration} fields are:
10402 @deftypevr {@code{files-configuration} parameter} log-location access-log
10403 Defines the access log filename. Specifying a blank filename disables
10404 access log generation. The value @code{stderr} causes log entries to be
10405 sent to the standard error file when the scheduler is running in the
10406 foreground, or to the system log daemon when run in the background. The
10407 value @code{syslog} causes log entries to be sent to the system log
10408 daemon. The server name may be included in filenames using the string
10409 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10411 Defaults to @samp{"/var/log/cups/access_log"}.
10414 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10415 Where CUPS should cache data.
10417 Defaults to @samp{"/var/cache/cups"}.
10420 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10421 Specifies the permissions for all configuration files that the scheduler
10424 Note that the permissions for the printers.conf file are currently
10425 masked to only allow access from the scheduler user (typically root).
10426 This is done because printer device URIs sometimes contain sensitive
10427 authentication information that should not be generally known on the
10428 system. There is no way to disable this security feature.
10430 Defaults to @samp{"0640"}.
10433 @deftypevr {@code{files-configuration} parameter} log-location error-log
10434 Defines the error log filename. Specifying a blank filename disables
10435 access log generation. The value @code{stderr} causes log entries to be
10436 sent to the standard error file when the scheduler is running in the
10437 foreground, or to the system log daemon when run in the background. The
10438 value @code{syslog} causes log entries to be sent to the system log
10439 daemon. The server name may be included in filenames using the string
10440 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10442 Defaults to @samp{"/var/log/cups/error_log"}.
10445 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10446 Specifies which errors are fatal, causing the scheduler to exit. The
10451 No errors are fatal.
10454 All of the errors below are fatal.
10457 Browsing initialization errors are fatal, for example failed connections
10458 to the DNS-SD daemon.
10461 Configuration file syntax errors are fatal.
10464 Listen or Port errors are fatal, except for IPv6 failures on the
10465 loopback or @code{any} addresses.
10468 Log file creation or write errors are fatal.
10471 Bad startup file permissions are fatal, for example shared TLS
10472 certificate and key files with world-read permissions.
10475 Defaults to @samp{"all -browse"}.
10478 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10479 Specifies whether the file pseudo-device can be used for new printer
10480 queues. The URI @uref{file:///dev/null} is always allowed.
10482 Defaults to @samp{#f}.
10485 @deftypevr {@code{files-configuration} parameter} string group
10486 Specifies the group name or ID that will be used when executing external
10489 Defaults to @samp{"lp"}.
10492 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10493 Specifies the permissions for all log files that the scheduler writes.
10495 Defaults to @samp{"0644"}.
10498 @deftypevr {@code{files-configuration} parameter} log-location page-log
10499 Defines the page log filename. Specifying a blank filename disables
10500 access log generation. The value @code{stderr} causes log entries to be
10501 sent to the standard error file when the scheduler is running in the
10502 foreground, or to the system log daemon when run in the background. The
10503 value @code{syslog} causes log entries to be sent to the system log
10504 daemon. The server name may be included in filenames using the string
10505 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10507 Defaults to @samp{"/var/log/cups/page_log"}.
10510 @deftypevr {@code{files-configuration} parameter} string remote-root
10511 Specifies the username that is associated with unauthenticated accesses
10512 by clients claiming to be the root user. The default is @code{remroot}.
10514 Defaults to @samp{"remroot"}.
10517 @deftypevr {@code{files-configuration} parameter} file-name request-root
10518 Specifies the directory that contains print jobs and other HTTP request
10521 Defaults to @samp{"/var/spool/cups"}.
10524 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10525 Specifies the level of security sandboxing that is applied to print
10526 filters, backends, and other child processes of the scheduler; either
10527 @code{relaxed} or @code{strict}. This directive is currently only
10528 used/supported on macOS.
10530 Defaults to @samp{strict}.
10533 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10534 Specifies the location of TLS certificates and private keys. CUPS will
10535 look for public and private keys in this directory: a @code{.crt} files
10536 for PEM-encoded certificates and corresponding @code{.key} files for
10537 PEM-encoded private keys.
10539 Defaults to @samp{"/etc/cups/ssl"}.
10542 @deftypevr {@code{files-configuration} parameter} file-name server-root
10543 Specifies the directory containing the server configuration files.
10545 Defaults to @samp{"/etc/cups"}.
10548 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10549 Specifies whether the scheduler calls fsync(2) after writing
10550 configuration or state files.
10552 Defaults to @samp{#f}.
10555 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10556 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10559 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10560 Specifies the directory where temporary files are stored.
10562 Defaults to @samp{"/var/spool/cups/tmp"}.
10565 @deftypevr {@code{files-configuration} parameter} string user
10566 Specifies the user name or ID that is used when running external
10569 Defaults to @samp{"lp"}.
10573 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10574 Specifies the logging level for the AccessLog file. The @code{config}
10575 level logs when printers and classes are added, deleted, or modified and
10576 when configuration files are accessed or updated. The @code{actions}
10577 level logs when print jobs are submitted, held, released, modified, or
10578 canceled, and any of the conditions for @code{config}. The @code{all}
10579 level logs all requests.
10581 Defaults to @samp{actions}.
10584 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10585 Specifies whether to purge job history data automatically when it is no
10586 longer required for quotas.
10588 Defaults to @samp{#f}.
10591 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10592 Specifies which protocols to use for local printer sharing.
10594 Defaults to @samp{dnssd}.
10597 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10598 Specifies whether the CUPS web interface is advertised.
10600 Defaults to @samp{#f}.
10603 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10604 Specifies whether shared printers are advertised.
10606 Defaults to @samp{#f}.
10609 @deftypevr {@code{cups-configuration} parameter} string classification
10610 Specifies the security classification of the server. Any valid banner
10611 name can be used, including "classified", "confidential", "secret",
10612 "topsecret", and "unclassified", or the banner can be omitted to disable
10613 secure printing functions.
10615 Defaults to @samp{""}.
10618 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
10619 Specifies whether users may override the classification (cover page) of
10620 individual print jobs using the @code{job-sheets} option.
10622 Defaults to @samp{#f}.
10625 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
10626 Specifies the default type of authentication to use.
10628 Defaults to @samp{Basic}.
10631 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
10632 Specifies whether encryption will be used for authenticated requests.
10634 Defaults to @samp{Required}.
10637 @deftypevr {@code{cups-configuration} parameter} string default-language
10638 Specifies the default language to use for text and web content.
10640 Defaults to @samp{"en"}.
10643 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
10644 Specifies the default paper size for new print queues. @samp{"Auto"}
10645 uses a locale-specific default, while @samp{"None"} specifies there is
10646 no default paper size. Specific size names are typically
10647 @samp{"Letter"} or @samp{"A4"}.
10649 Defaults to @samp{"Auto"}.
10652 @deftypevr {@code{cups-configuration} parameter} string default-policy
10653 Specifies the default access policy to use.
10655 Defaults to @samp{"default"}.
10658 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
10659 Specifies whether local printers are shared by default.
10661 Defaults to @samp{#t}.
10664 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
10665 Specifies the delay for updating of configuration and state files, in
10666 seconds. A value of 0 causes the update to happen as soon as possible,
10667 typically within a few milliseconds.
10669 Defaults to @samp{30}.
10672 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
10673 Specifies what to do when an error occurs. Possible values are
10674 @code{abort-job}, which will discard the failed print job;
10675 @code{retry-job}, which will retry the job at a later time;
10676 @code{retry-this-job}, which retries the failed job immediately; and
10677 @code{stop-printer}, which stops the printer.
10679 Defaults to @samp{stop-printer}.
10682 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
10683 Specifies the maximum cost of filters that are run concurrently, which
10684 can be used to minimize disk, memory, and CPU resource problems. A
10685 limit of 0 disables filter limiting. An average print to a
10686 non-PostScript printer needs a filter limit of about 200. A PostScript
10687 printer needs about half that (100). Setting the limit below these
10688 thresholds will effectively limit the scheduler to printing a single job
10691 Defaults to @samp{0}.
10694 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
10695 Specifies the scheduling priority of filters that are run to print a
10696 job. The nice value ranges from 0, the highest priority, to 19, the
10699 Defaults to @samp{0}.
10702 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
10703 Specifies whether to do reverse lookups on connecting clients. The
10704 @code{double} setting causes @code{cupsd} to verify that the hostname
10705 resolved from the address matches one of the addresses returned for that
10706 hostname. Double lookups also prevent clients with unregistered
10707 addresses from connecting to your server. Only set this option to
10708 @code{#t} or @code{double} if absolutely required.
10710 Defaults to @samp{#f}.
10713 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
10714 Specifies the number of seconds to wait before killing the filters and
10715 backend associated with a canceled or held job.
10717 Defaults to @samp{30}.
10720 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
10721 Specifies the interval between retries of jobs in seconds. This is
10722 typically used for fax queues but can also be used with normal print
10723 queues whose error policy is @code{retry-job} or
10724 @code{retry-current-job}.
10726 Defaults to @samp{30}.
10729 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
10730 Specifies the number of retries that are done for jobs. This is
10731 typically used for fax queues but can also be used with normal print
10732 queues whose error policy is @code{retry-job} or
10733 @code{retry-current-job}.
10735 Defaults to @samp{5}.
10738 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
10739 Specifies whether to support HTTP keep-alive connections.
10741 Defaults to @samp{#t}.
10744 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
10745 Specifies how long an idle client connection remains open, in seconds.
10747 Defaults to @samp{30}.
10750 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
10751 Specifies the maximum size of print files, IPP requests, and HTML form
10752 data. A limit of 0 disables the limit check.
10754 Defaults to @samp{0}.
10757 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
10758 Listens on the specified interfaces for connections. Valid values are
10759 of the form @var{address}:@var{port}, where @var{address} is either an
10760 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
10761 indicate all addresses. Values can also be file names of local UNIX
10762 domain sockets. The Listen directive is similar to the Port directive
10763 but allows you to restrict access to specific interfaces or networks.
10766 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
10767 Specifies the number of pending connections that will be allowed. This
10768 normally only affects very busy servers that have reached the MaxClients
10769 limit, but can also be triggered by large numbers of simultaneous
10770 connections. When the limit is reached, the operating system will
10771 refuse additional connections until the scheduler can accept the pending
10774 Defaults to @samp{128}.
10777 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
10778 Specifies a set of additional access controls.
10780 Available @code{location-access-controls} fields are:
10782 @deftypevr {@code{location-access-controls} parameter} file-name path
10783 Specifies the URI path to which the access control applies.
10786 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
10787 Access controls for all access to this path, in the same format as the
10788 @code{access-controls} of @code{operation-access-control}.
10790 Defaults to @samp{()}.
10793 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
10794 Access controls for method-specific access to this path.
10796 Defaults to @samp{()}.
10798 Available @code{method-access-controls} fields are:
10800 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
10801 If @code{#t}, apply access controls to all methods except the listed
10802 methods. Otherwise apply to only the listed methods.
10804 Defaults to @samp{#f}.
10807 @deftypevr {@code{method-access-controls} parameter} method-list methods
10808 Methods to which this access control applies.
10810 Defaults to @samp{()}.
10813 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
10814 Access control directives, as a list of strings. Each string should be
10815 one directive, such as "Order allow,deny".
10817 Defaults to @samp{()}.
10822 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
10823 Specifies the number of debugging messages that are retained for logging
10824 if an error occurs in a print job. Debug messages are logged regardless
10825 of the LogLevel setting.
10827 Defaults to @samp{100}.
10830 @deftypevr {@code{cups-configuration} parameter} log-level log-level
10831 Specifies the level of logging for the ErrorLog file. The value
10832 @code{none} stops all logging while @code{debug2} logs everything.
10834 Defaults to @samp{info}.
10837 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
10838 Specifies the format of the date and time in the log files. The value
10839 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
10841 Defaults to @samp{standard}.
10844 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
10845 Specifies the maximum number of simultaneous clients that are allowed by
10848 Defaults to @samp{100}.
10851 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
10852 Specifies the maximum number of simultaneous clients that are allowed
10853 from a single address.
10855 Defaults to @samp{100}.
10858 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
10859 Specifies the maximum number of copies that a user can print of each
10862 Defaults to @samp{9999}.
10865 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
10866 Specifies the maximum time a job may remain in the @code{indefinite}
10867 hold state before it is canceled. A value of 0 disables cancellation of
10870 Defaults to @samp{0}.
10873 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
10874 Specifies the maximum number of simultaneous jobs that are allowed. Set
10875 to 0 to allow an unlimited number of jobs.
10877 Defaults to @samp{500}.
10880 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
10881 Specifies the maximum number of simultaneous jobs that are allowed per
10882 printer. A value of 0 allows up to MaxJobs jobs per printer.
10884 Defaults to @samp{0}.
10887 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
10888 Specifies the maximum number of simultaneous jobs that are allowed per
10889 user. A value of 0 allows up to MaxJobs jobs per user.
10891 Defaults to @samp{0}.
10894 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
10895 Specifies the maximum time a job may take to print before it is
10896 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
10898 Defaults to @samp{10800}.
10901 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
10902 Specifies the maximum size of the log files before they are rotated, in
10903 bytes. The value 0 disables log rotation.
10905 Defaults to @samp{1048576}.
10908 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
10909 Specifies the maximum amount of time to allow between files in a
10910 multiple file print job, in seconds.
10912 Defaults to @samp{300}.
10915 @deftypevr {@code{cups-configuration} parameter} string page-log-format
10916 Specifies the format of PageLog lines. Sequences beginning with percent
10917 (@samp{%}) characters are replaced with the corresponding information,
10918 while all other characters are copied literally. The following percent
10919 sequences are recognized:
10923 insert a single percent character
10926 insert the value of the specified IPP attribute
10929 insert the number of copies for the current page
10932 insert the current page number
10935 insert the current date and time in common log format
10941 insert the printer name
10944 insert the username
10947 A value of the empty string disables page logging. The string @code{%p
10948 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
10949 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
10952 Defaults to @samp{""}.
10955 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
10956 Passes the specified environment variable(s) to child processes; a list
10959 Defaults to @samp{()}.
10962 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
10963 Specifies named access control policies.
10965 Available @code{policy-configuration} fields are:
10967 @deftypevr {@code{policy-configuration} parameter} string name
10968 Name of the policy.
10971 @deftypevr {@code{policy-configuration} parameter} string job-private-access
10972 Specifies an access list for a job's private values. @code{@@ACL} maps
10973 to the printer's requesting-user-name-allowed or
10974 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10975 owner. @code{@@SYSTEM} maps to the groups listed for the
10976 @code{system-group} field of the @code{files-config} configuration,
10977 which is reified into the @code{cups-files.conf(5)} file. Other
10978 possible elements of the access list include specific user names, and
10979 @code{@@@var{group}} to indicate members of a specific group. The
10980 access list may also be simply @code{all} or @code{default}.
10982 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10985 @deftypevr {@code{policy-configuration} parameter} string job-private-values
10986 Specifies the list of job values to make private, or @code{all},
10987 @code{default}, or @code{none}.
10989 Defaults to @samp{"job-name job-originating-host-name
10990 job-originating-user-name phone"}.
10993 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
10994 Specifies an access list for a subscription's private values.
10995 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
10996 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10997 owner. @code{@@SYSTEM} maps to the groups listed for the
10998 @code{system-group} field of the @code{files-config} configuration,
10999 which is reified into the @code{cups-files.conf(5)} file. Other
11000 possible elements of the access list include specific user names, and
11001 @code{@@@var{group}} to indicate members of a specific group. The
11002 access list may also be simply @code{all} or @code{default}.
11004 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11007 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
11008 Specifies the list of job values to make private, or @code{all},
11009 @code{default}, or @code{none}.
11011 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
11012 notify-subscriber-user-name notify-user-data"}.
11015 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
11016 Access control by IPP operation.
11018 Defaults to @samp{()}.
11022 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
11023 Specifies whether job files (documents) are preserved after a job is
11024 printed. If a numeric value is specified, job files are preserved for
11025 the indicated number of seconds after printing. Otherwise a boolean
11026 value applies indefinitely.
11028 Defaults to @samp{86400}.
11031 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
11032 Specifies whether the job history is preserved after a job is printed.
11033 If a numeric value is specified, the job history is preserved for the
11034 indicated number of seconds after printing. If @code{#t}, the job
11035 history is preserved until the MaxJobs limit is reached.
11037 Defaults to @samp{#t}.
11040 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
11041 Specifies the amount of time to wait for job completion before
11042 restarting the scheduler.
11044 Defaults to @samp{30}.
11047 @deftypevr {@code{cups-configuration} parameter} string rip-cache
11048 Specifies the maximum amount of memory to use when converting documents
11049 into bitmaps for a printer.
11051 Defaults to @samp{"128m"}.
11054 @deftypevr {@code{cups-configuration} parameter} string server-admin
11055 Specifies the email address of the server administrator.
11057 Defaults to @samp{"root@@localhost.localdomain"}.
11060 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
11061 The ServerAlias directive is used for HTTP Host header validation when
11062 clients connect to the scheduler from external interfaces. Using the
11063 special name @code{*} can expose your system to known browser-based DNS
11064 rebinding attacks, even when accessing sites through a firewall. If the
11065 auto-discovery of alternate names does not work, we recommend listing
11066 each alternate name with a ServerAlias directive instead of using
11069 Defaults to @samp{*}.
11072 @deftypevr {@code{cups-configuration} parameter} string server-name
11073 Specifies the fully-qualified host name of the server.
11075 Defaults to @samp{"localhost"}.
11078 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
11079 Specifies what information is included in the Server header of HTTP
11080 responses. @code{None} disables the Server header. @code{ProductOnly}
11081 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
11082 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
11083 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
11084 the output of the @code{uname} command. @code{Full} reports @code{CUPS
11085 2.0.0 (@var{uname}) IPP/2.0}.
11087 Defaults to @samp{Minimal}.
11090 @deftypevr {@code{cups-configuration} parameter} string set-env
11091 Set the specified environment variable to be passed to child processes.
11093 Defaults to @samp{"variable value"}.
11096 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
11097 Listens on the specified interfaces for encrypted connections. Valid
11098 values are of the form @var{address}:@var{port}, where @var{address} is
11099 either an IPv6 address enclosed in brackets, an IPv4 address, or
11100 @code{*} to indicate all addresses.
11102 Defaults to @samp{()}.
11105 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
11106 Sets encryption options. By default, CUPS only supports encryption
11107 using TLS v1.0 or higher using known secure cipher suites. The
11108 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
11109 required for some older clients that do not implement newer ones. The
11110 @code{AllowSSL3} option enables SSL v3.0, which is required for some
11111 older clients that do not support TLS v1.0.
11113 Defaults to @samp{()}.
11116 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
11117 Specifies whether the scheduler requires clients to strictly adhere to
11118 the IPP specifications.
11120 Defaults to @samp{#f}.
11123 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
11124 Specifies the HTTP request timeout, in seconds.
11126 Defaults to @samp{300}.
11130 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
11131 Specifies whether the web interface is enabled.
11133 Defaults to @samp{#f}.
11136 At this point you're probably thinking ``oh dear, Guix manual, I like
11137 you but you can stop already with the configuration options''. Indeed.
11138 However, one more point: it could be that you have an existing
11139 @code{cupsd.conf} that you want to use. In that case, you can pass an
11140 @code{opaque-cups-configuration} as the configuration of a
11141 @code{cups-service-type}.
11143 Available @code{opaque-cups-configuration} fields are:
11145 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
11149 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
11150 The contents of the @code{cupsd.conf}, as a string.
11153 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
11154 The contents of the @code{cups-files.conf} file, as a string.
11157 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
11158 strings of the same name, you could instantiate a CUPS service like
11162 (service cups-service-type
11163 (opaque-cups-configuration
11164 (cupsd.conf cupsd.conf)
11165 (cups-files.conf cups-files.conf)))
11169 @node Desktop Services
11170 @subsubsection Desktop Services
11172 The @code{(gnu services desktop)} module provides services that are
11173 usually useful in the context of a ``desktop'' setup---that is, on a
11174 machine running a graphical display server, possibly with graphical user
11175 interfaces, etc. It also defines services that provide specific desktop
11176 environments like GNOME and XFCE.
11178 To simplify things, the module defines a variable containing the set of
11179 services that users typically expect on a machine with a graphical
11180 environment and networking:
11182 @defvr {Scheme Variable} %desktop-services
11183 This is a list of services that builds upon @var{%base-services} and
11184 adds or adjusts services for a typical ``desktop'' setup.
11186 In particular, it adds a graphical login manager (@pxref{X Window,
11187 @code{slim-service}}), screen lockers,
11188 a network management tool (@pxref{Networking
11189 Services, @code{wicd-service}}), energy and color management services,
11190 the @code{elogind} login and seat manager, the Polkit privilege service,
11191 the GeoClue location service, an NTP client (@pxref{Networking
11192 Services}), the Avahi daemon, and has the name service switch service
11193 configured to be able to use @code{nss-mdns} (@pxref{Name Service
11197 The @var{%desktop-services} variable can be used as the @code{services}
11198 field of an @code{operating-system} declaration (@pxref{operating-system
11199 Reference, @code{services}}).
11201 Additionally, the @code{gnome-desktop-service} and
11202 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11203 system. To ``add GNOME'' means that system-level services like the
11204 backlight adjustment helpers and the power management utilities are
11205 added to the system, extending @code{polkit} and @code{dbus}
11206 appropriately, allowing GNOME to operate with elevated privileges on a
11207 limited number of special-purpose system interfaces. Additionally,
11208 adding a service made by @code{gnome-desktop-service} adds the GNOME
11209 metapackage to the system profile. Likewise, adding the XFCE service
11210 not only adds the @code{xfce} metapackage to the system profile, but it
11211 also gives the Thunar file manager the ability to open a ``root-mode''
11212 file management window, if the user authenticates using the
11213 administrator's password via the standard polkit graphical interface.
11215 @deffn {Scheme Procedure} gnome-desktop-service
11216 Return a service that adds the @code{gnome} package to the system
11217 profile, and extends polkit with the actions from
11218 @code{gnome-settings-daemon}.
11221 @deffn {Scheme Procedure} xfce-desktop-service
11222 Return a service that adds the @code{xfce} package to the system profile,
11223 and extends polkit with the ability for @code{thunar} to manipulate the
11224 file system as root from within a user session, after the user has
11225 authenticated with the administrator's password.
11228 Because the GNOME and XFCE desktop services pull in so many packages,
11229 the default @code{%desktop-services} variable doesn't include either of
11230 them by default. To add GNOME or XFCE, just @code{cons} them onto
11231 @code{%desktop-services} in the @code{services} field of your
11232 @code{operating-system}:
11235 (use-modules (gnu))
11236 (use-service-modules desktop)
11239 ;; cons* adds items to the list given as its last argument.
11240 (services (cons* (gnome-desktop-service)
11241 (xfce-desktop-service)
11242 %desktop-services))
11246 These desktop environments will then be available as options in the
11247 graphical login window.
11249 The actual service definitions included in @code{%desktop-services} and
11250 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
11251 are described below.
11253 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
11254 Return a service that runs the ``system bus'', using @var{dbus}, with
11255 support for @var{services}.
11257 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11258 facility. Its system bus is used to allow system services to communicate
11259 and to be notified of system-wide events.
11261 @var{services} must be a list of packages that provide an
11262 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11263 and policy files. For example, to allow avahi-daemon to use the system bus,
11264 @var{services} must be equal to @code{(list avahi)}.
11267 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11268 Return a service that runs the @code{elogind} login and
11269 seat management daemon. @uref{https://github.com/andywingo/elogind,
11270 Elogind} exposes a D-Bus interface that can be used to know which users
11271 are logged in, know what kind of sessions they have open, suspend the
11272 system, inhibit system suspend, reboot the system, and other tasks.
11274 Elogind handles most system-level power events for a computer, for
11275 example suspending the system when a lid is closed, or shutting it down
11276 when the power button is pressed.
11278 The @var{config} keyword argument specifies the configuration for
11279 elogind, and should be the result of an @code{(elogind-configuration
11280 (@var{parameter} @var{value})...)} invocation. Available parameters and
11281 their default values are:
11284 @item kill-user-processes?
11286 @item kill-only-users
11288 @item kill-exclude-users
11290 @item inhibit-delay-max-seconds
11292 @item handle-power-key
11294 @item handle-suspend-key
11296 @item handle-hibernate-key
11298 @item handle-lid-switch
11300 @item handle-lid-switch-docked
11302 @item power-key-ignore-inhibited?
11304 @item suspend-key-ignore-inhibited?
11306 @item hibernate-key-ignore-inhibited?
11308 @item lid-switch-ignore-inhibited?
11310 @item holdoff-timeout-seconds
11314 @item idle-action-seconds
11316 @item runtime-directory-size-percent
11318 @item runtime-directory-size
11322 @item suspend-state
11323 @code{("mem" "standby" "freeze")}
11326 @item hibernate-state
11328 @item hibernate-mode
11329 @code{("platform" "shutdown")}
11330 @item hybrid-sleep-state
11332 @item hybrid-sleep-mode
11333 @code{("suspend" "platform" "shutdown")}
11337 @deffn {Scheme Procedure} polkit-service @
11338 [#:polkit @var{polkit}]
11339 Return a service that runs the
11340 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11341 management service}, which allows system administrators to grant access to
11342 privileged operations in a structured way. By querying the Polkit service, a
11343 privileged system component can know when it should grant additional
11344 capabilities to ordinary users. For example, an ordinary user can be granted
11345 the capability to suspend the system if the user is logged in locally.
11348 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11349 [#:watts-up-pro? #f] @
11350 [#:poll-batteries? #t] @
11351 [#:ignore-lid? #f] @
11352 [#:use-percentage-for-policy? #f] @
11353 [#:percentage-low 10] @
11354 [#:percentage-critical 3] @
11355 [#:percentage-action 2] @
11356 [#:time-low 1200] @
11357 [#:time-critical 300] @
11358 [#:time-action 120] @
11359 [#:critical-power-action 'hybrid-sleep]
11360 Return a service that runs @uref{http://upower.freedesktop.org/,
11361 @command{upowerd}}, a system-wide monitor for power consumption and battery
11362 levels, with the given configuration settings. It implements the
11363 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11367 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11368 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11369 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11370 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11371 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11374 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11375 Return a service that runs @command{colord}, a system service with a D-Bus
11376 interface to manage the color profiles of input and output devices such as
11377 screens and scanners. It is notably used by the GNOME Color Manager graphical
11378 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11379 site} for more information.
11382 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11383 Return a configuration allowing an application to access GeoClue
11384 location data. @var{name} is the Desktop ID of the application, without
11385 the @code{.desktop} part. If @var{allowed?} is true, the application
11386 will have access to location information by default. The boolean
11387 @var{system?} value indicates whether an application is a system component
11388 or not. Finally @var{users} is a list of UIDs of all users for which
11389 this application is allowed location info access. An empty users list
11390 means that all users are allowed.
11393 @defvr {Scheme Variable} %standard-geoclue-applications
11394 The standard list of well-known GeoClue application configurations,
11395 granting authority to the GNOME date-and-time utility to ask for the
11396 current location in order to set the time zone, and allowing the
11397 IceCat and Epiphany web browsers to request location information.
11398 IceCat and Epiphany both query the user before allowing a web page to
11399 know the user's location.
11402 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11403 [#:whitelist '()] @
11404 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11405 [#:submit-data? #f]
11406 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11407 [#:submission-nick "geoclue"] @
11408 [#:applications %standard-geoclue-applications]
11409 Return a service that runs the GeoClue location service. This service
11410 provides a D-Bus interface to allow applications to request access to a
11411 user's physical location, and optionally to add information to online
11412 location databases. See
11413 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11414 web site} for more information.
11417 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
11418 Return a service that runs the @command{bluetoothd} daemon, which manages
11419 all the Bluetooth devices and provides a number of D-Bus interfaces.
11421 Users need to be in the @code{lp} group to access the D-Bus service.
11424 @node Database Services
11425 @subsubsection Database Services
11429 The @code{(gnu services databases)} module provides the following services.
11431 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11432 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11433 [#:port 5432] [#:locale ``en_US.utf8'']
11434 Return a service that runs @var{postgresql}, the PostgreSQL database
11437 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11438 creates a database cluster with @var{locale} as the default
11439 locale, stored in @var{data-directory}. It then listens on @var{port}.
11442 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11443 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11446 The optional @var{config} argument specifies the configuration for
11447 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11450 @deftp {Data Type} mysql-configuration
11451 Data type representing the configuration of @var{mysql-service}.
11454 @item @code{mysql} (default: @var{mariadb})
11455 Package object of the MySQL database server, can be either @var{mariadb}
11458 For MySQL, a temporary root password will be displayed at activation time.
11459 For MariaDB, the root password is empty.
11461 @item @code{port} (default: @code{3306})
11462 TCP port on which the database server listens for incoming connections.
11466 @defvr {Scheme Variable} redis-service-type
11467 This is the service type for the @uref{https://redis.io/, Redis}
11468 key/value store, whose value is a @code{redis-configuration} object.
11471 @deftp {Data Type} redis-configuration
11472 Data type representing the configuration of redis.
11475 @item @code{redis} (default: @code{redis})
11476 The Redis package to use.
11478 @item @code{bind} (default: @code{"127.0.0.1"})
11479 Network interface on which to listen.
11481 @item @code{port} (default: @code{6379})
11482 Port on which to accept connections on, a value of 0 will disable
11483 listening on a TCP socket.
11485 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11486 Directory in which to store the database and related files.
11490 @node Mail Services
11491 @subsubsection Mail Services
11495 The @code{(gnu services mail)} module provides Guix service definitions
11496 for email services: IMAP, POP3, and LMTP servers, as well as mail
11497 transport agents (MTAs). Lots of acronyms! These services are detailed
11498 in the subsections below.
11500 @subsubheading Dovecot Service
11502 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11503 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11506 By default, Dovecot does not need much configuration; the default
11507 configuration object created by @code{(dovecot-configuration)} will
11508 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11509 certificate will be generated for TLS-protected connections, though
11510 Dovecot will also listen on cleartext ports by default. There are a
11511 number of options, though, which mail administrators might need to change,
11512 and as is the case with other services, Guix allows the system
11513 administrator to specify these parameters via a uniform Scheme interface.
11515 For example, to specify that mail is located at @code{maildir~/.mail},
11516 one would instantiate the Dovecot service like this:
11519 (dovecot-service #:config
11520 (dovecot-configuration
11521 (mail-location "maildir:~/.mail")))
11524 The available configuration parameters follow. Each parameter
11525 definition is preceded by its type; for example, @samp{string-list foo}
11526 indicates that the @code{foo} parameter should be specified as a list of
11527 strings. There is also a way to specify the configuration as a string,
11528 if you have an old @code{dovecot.conf} file that you want to port over
11529 from some other system; see the end for more details.
11531 @c The following documentation was initially generated by
11532 @c (generate-documentation) in (gnu services mail). Manually maintained
11533 @c documentation is better, so we shouldn't hesitate to edit below as
11534 @c needed. However if the change you want to make to this documentation
11535 @c can be done in an automated way, it's probably easier to change
11536 @c (generate-documentation) than to make it below and have to deal with
11537 @c the churn as dovecot updates.
11539 Available @code{dovecot-configuration} fields are:
11541 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11542 The dovecot package.
11545 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11546 A list of IPs or hosts where to listen for connections. @samp{*}
11547 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11548 interfaces. If you want to specify non-default ports or anything more
11549 complex, customize the address and port fields of the
11550 @samp{inet-listener} of the specific services you are interested in.
11553 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11554 List of protocols we want to serve. Available protocols include
11555 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11557 Available @code{protocol-configuration} fields are:
11559 @deftypevr {@code{protocol-configuration} parameter} string name
11560 The name of the protocol.
11563 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
11564 UNIX socket path to the master authentication server to find users.
11565 This is used by imap (for shared users) and lda.
11566 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11569 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
11570 Space separated list of plugins to load.
11573 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
11574 Maximum number of IMAP connections allowed for a user from each IP
11575 address. NOTE: The username is compared case-sensitively.
11576 Defaults to @samp{10}.
11581 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
11582 List of services to enable. Available services include @samp{imap},
11583 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
11586 Available @code{service-configuration} fields are:
11588 @deftypevr {@code{service-configuration} parameter} string kind
11589 The service kind. Valid values include @code{director},
11590 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
11591 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
11592 @code{tcpwrap}, @code{quota-warning}, or anything else.
11595 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
11596 Listeners for the service. A listener is either a
11597 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
11598 an @code{inet-listener-configuration}.
11599 Defaults to @samp{()}.
11601 Available @code{unix-listener-configuration} fields are:
11603 @deftypevr {@code{unix-listener-configuration} parameter} string path
11604 Path to the file, relative to @code{base-dir} field. This is also used as
11608 @deftypevr {@code{unix-listener-configuration} parameter} string mode
11609 The access mode for the socket.
11610 Defaults to @samp{"0600"}.
11613 @deftypevr {@code{unix-listener-configuration} parameter} string user
11614 The user to own the socket.
11615 Defaults to @samp{""}.
11618 @deftypevr {@code{unix-listener-configuration} parameter} string group
11619 The group to own the socket.
11620 Defaults to @samp{""}.
11624 Available @code{fifo-listener-configuration} fields are:
11626 @deftypevr {@code{fifo-listener-configuration} parameter} string path
11627 Path to the file, relative to @code{base-dir} field. This is also used as
11631 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
11632 The access mode for the socket.
11633 Defaults to @samp{"0600"}.
11636 @deftypevr {@code{fifo-listener-configuration} parameter} string user
11637 The user to own the socket.
11638 Defaults to @samp{""}.
11641 @deftypevr {@code{fifo-listener-configuration} parameter} string group
11642 The group to own the socket.
11643 Defaults to @samp{""}.
11647 Available @code{inet-listener-configuration} fields are:
11649 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
11650 The protocol to listen for.
11653 @deftypevr {@code{inet-listener-configuration} parameter} string address
11654 The address on which to listen, or empty for all addresses.
11655 Defaults to @samp{""}.
11658 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
11659 The port on which to listen.
11662 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
11663 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
11665 Defaults to @samp{#t}.
11670 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
11671 Number of connections to handle before starting a new process.
11672 Typically the only useful values are 0 (unlimited) or 1. 1 is more
11673 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
11674 Defaults to @samp{1}.
11677 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
11678 Number of processes to always keep waiting for more connections.
11679 Defaults to @samp{0}.
11682 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
11683 If you set @samp{service-count 0}, you probably need to grow
11685 Defaults to @samp{256000000}.
11690 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
11691 Dict configuration, as created by the @code{dict-configuration}
11694 Available @code{dict-configuration} fields are:
11696 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
11697 A list of key-value pairs that this dict should hold.
11698 Defaults to @samp{()}.
11703 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
11704 A list of passdb configurations, each one created by the
11705 @code{passdb-configuration} constructor.
11707 Available @code{passdb-configuration} fields are:
11709 @deftypevr {@code{passdb-configuration} parameter} string driver
11710 The driver that the passdb should use. Valid values include
11711 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
11713 Defaults to @samp{"pam"}.
11716 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
11717 Space separated list of arguments to the passdb driver.
11718 Defaults to @samp{""}.
11723 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
11724 List of userdb configurations, each one created by the
11725 @code{userdb-configuration} constructor.
11727 Available @code{userdb-configuration} fields are:
11729 @deftypevr {@code{userdb-configuration} parameter} string driver
11730 The driver that the userdb should use. Valid values include
11731 @samp{passwd} and @samp{static}.
11732 Defaults to @samp{"passwd"}.
11735 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
11736 Space separated list of arguments to the userdb driver.
11737 Defaults to @samp{""}.
11740 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
11741 Override fields from passwd.
11742 Defaults to @samp{()}.
11747 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
11748 Plug-in configuration, created by the @code{plugin-configuration}
11752 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
11753 List of namespaces. Each item in the list is created by the
11754 @code{namespace-configuration} constructor.
11756 Available @code{namespace-configuration} fields are:
11758 @deftypevr {@code{namespace-configuration} parameter} string name
11759 Name for this namespace.
11762 @deftypevr {@code{namespace-configuration} parameter} string type
11763 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
11764 Defaults to @samp{"private"}.
11767 @deftypevr {@code{namespace-configuration} parameter} string separator
11768 Hierarchy separator to use. You should use the same separator for
11769 all namespaces or some clients get confused. @samp{/} is usually a good
11770 one. The default however depends on the underlying mail storage
11772 Defaults to @samp{""}.
11775 @deftypevr {@code{namespace-configuration} parameter} string prefix
11776 Prefix required to access this namespace. This needs to be
11777 different for all namespaces. For example @samp{Public/}.
11778 Defaults to @samp{""}.
11781 @deftypevr {@code{namespace-configuration} parameter} string location
11782 Physical location of the mailbox. This is in the same format as
11783 mail_location, which is also the default for it.
11784 Defaults to @samp{""}.
11787 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
11788 There can be only one INBOX, and this setting defines which
11790 Defaults to @samp{#f}.
11793 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
11794 If namespace is hidden, it's not advertised to clients via NAMESPACE
11795 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
11796 useful when converting from another server with different namespaces
11797 which you want to deprecate but still keep working. For example you can
11798 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
11800 Defaults to @samp{#f}.
11803 @deftypevr {@code{namespace-configuration} parameter} boolean list?
11804 Show the mailboxes under this namespace with the LIST command. This
11805 makes the namespace visible for clients that do not support the NAMESPACE
11806 extension. The special @code{children} value lists child mailboxes, but
11807 hides the namespace prefix.
11808 Defaults to @samp{#t}.
11811 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
11812 Namespace handles its own subscriptions. If set to @code{#f}, the
11813 parent namespace handles them. The empty prefix should always have this
11815 Defaults to @samp{#t}.
11818 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
11819 List of predefined mailboxes in this namespace.
11820 Defaults to @samp{()}.
11822 Available @code{mailbox-configuration} fields are:
11824 @deftypevr {@code{mailbox-configuration} parameter} string name
11825 Name for this mailbox.
11828 @deftypevr {@code{mailbox-configuration} parameter} string auto
11829 @samp{create} will automatically create this mailbox.
11830 @samp{subscribe} will both create and subscribe to the mailbox.
11831 Defaults to @samp{"no"}.
11834 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
11835 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
11836 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
11837 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
11838 Defaults to @samp{()}.
11845 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
11846 Base directory where to store runtime data.
11847 Defaults to @samp{"/var/run/dovecot/"}.
11850 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
11851 Greeting message for clients.
11852 Defaults to @samp{"Dovecot ready."}.
11855 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
11856 List of trusted network ranges. Connections from these IPs are
11857 allowed to override their IP addresses and ports (for logging and for
11858 authentication checks). @samp{disable-plaintext-auth} is also ignored
11859 for these networks. Typically you would specify your IMAP proxy servers
11861 Defaults to @samp{()}.
11864 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
11865 List of login access check sockets (e.g. tcpwrap).
11866 Defaults to @samp{()}.
11869 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
11870 Show more verbose process titles (in ps). Currently shows user name
11871 and IP address. Useful for seeing who is actually using the IMAP
11872 processes (e.g. shared mailboxes or if the same uid is used for multiple
11874 Defaults to @samp{#f}.
11877 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
11878 Should all processes be killed when Dovecot master process shuts down.
11879 Setting this to @code{#f} means that Dovecot can be upgraded without
11880 forcing existing client connections to close (although that could also
11881 be a problem if the upgrade is e.g. due to a security fix).
11882 Defaults to @samp{#t}.
11885 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
11886 If non-zero, run mail commands via this many connections to doveadm
11887 server, instead of running them directly in the same process.
11888 Defaults to @samp{0}.
11891 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
11892 UNIX socket or host:port used for connecting to doveadm server.
11893 Defaults to @samp{"doveadm-server"}.
11896 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
11897 List of environment variables that are preserved on Dovecot startup
11898 and passed down to all of its child processes. You can also give
11899 key=value pairs to always set specific settings.
11902 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
11903 Disable LOGIN command and all other plaintext authentications unless
11904 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
11905 matches the local IP (i.e. you're connecting from the same computer),
11906 the connection is considered secure and plaintext authentication is
11907 allowed. See also ssl=required setting.
11908 Defaults to @samp{#t}.
11911 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
11912 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
11913 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
11914 for caching to be used.
11915 Defaults to @samp{0}.
11918 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
11919 Time to live for cached data. After TTL expires the cached record
11920 is no longer used, *except* if the main database lookup returns internal
11921 failure. We also try to handle password changes automatically: If
11922 user's previous authentication was successful, but this one wasn't, the
11923 cache isn't used. For now this works only with plaintext
11925 Defaults to @samp{"1 hour"}.
11928 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
11929 TTL for negative hits (user not found, password mismatch).
11930 0 disables caching them completely.
11931 Defaults to @samp{"1 hour"}.
11934 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
11935 List of realms for SASL authentication mechanisms that need them.
11936 You can leave it empty if you don't want to support multiple realms.
11937 Many clients simply use the first one listed here, so keep the default
11939 Defaults to @samp{()}.
11942 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
11943 Default realm/domain to use if none was specified. This is used for
11944 both SASL realms and appending @@domain to username in plaintext
11946 Defaults to @samp{""}.
11949 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
11950 List of allowed characters in username. If the user-given username
11951 contains a character not listed in here, the login automatically fails.
11952 This is just an extra check to make sure user can't exploit any
11953 potential quote escaping vulnerabilities with SQL/LDAP databases. If
11954 you want to allow all characters, set this value to empty.
11955 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
11958 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
11959 Username character translations before it's looked up from
11960 databases. The value contains series of from -> to characters. For
11961 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
11962 translated to @samp{@@}.
11963 Defaults to @samp{""}.
11966 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
11967 Username formatting before it's looked up from databases. You can
11968 use the standard variables here, e.g. %Lu would lowercase the username,
11969 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
11970 change the @samp{@@} into @samp{-AT-}. This translation is done after
11971 @samp{auth-username-translation} changes.
11972 Defaults to @samp{"%Lu"}.
11975 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
11976 If you want to allow master users to log in by specifying the master
11977 username within the normal username string (i.e. not using SASL
11978 mechanism's support for it), you can specify the separator character
11979 here. The format is then <username><separator><master username>.
11980 UW-IMAP uses @samp{*} as the separator, so that could be a good
11982 Defaults to @samp{""}.
11985 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
11986 Username to use for users logging in with ANONYMOUS SASL
11988 Defaults to @samp{"anonymous"}.
11991 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
11992 Maximum number of dovecot-auth worker processes. They're used to
11993 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
11994 They're automatically created and destroyed as needed.
11995 Defaults to @samp{30}.
11998 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
11999 Host name to use in GSSAPI principal names. The default is to use
12000 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
12001 allow all keytab entries.
12002 Defaults to @samp{""}.
12005 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
12006 Kerberos keytab to use for the GSSAPI mechanism. Will use the
12007 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
12008 need to change the auth service to run as root to be able to read this
12010 Defaults to @samp{""}.
12013 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
12014 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
12015 and @samp{ntlm-auth} helper.
12016 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
12017 Defaults to @samp{#f}.
12020 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
12021 Path for Samba's @samp{ntlm-auth} helper binary.
12022 Defaults to @samp{"/usr/bin/ntlm_auth"}.
12025 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
12026 Time to delay before replying to failed authentications.
12027 Defaults to @samp{"2 secs"}.
12030 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
12031 Require a valid SSL client certificate or the authentication
12033 Defaults to @samp{#f}.
12036 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
12037 Take the username from client's SSL certificate, using
12038 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
12040 Defaults to @samp{#f}.
12043 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
12044 List of wanted authentication mechanisms. Supported mechanisms are:
12045 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
12046 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
12047 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
12048 @samp{disable-plaintext-auth} setting.
12051 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
12052 List of IPs or hostnames to all director servers, including ourself.
12053 Ports can be specified as ip:port. The default port is the same as what
12054 director service's @samp{inet-listener} is using.
12055 Defaults to @samp{()}.
12058 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
12059 List of IPs or hostnames to all backend mail servers. Ranges are
12060 allowed too, like 10.0.0.10-10.0.0.30.
12061 Defaults to @samp{()}.
12064 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
12065 How long to redirect users to a specific server after it no longer
12066 has any connections.
12067 Defaults to @samp{"15 min"}.
12070 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
12071 TCP/IP port that accepts doveadm connections (instead of director
12072 connections) If you enable this, you'll also need to add
12073 @samp{inet-listener} for the port.
12074 Defaults to @samp{0}.
12077 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
12078 How the username is translated before being hashed. Useful values
12079 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
12080 are shared within domain.
12081 Defaults to @samp{"%Lu"}.
12084 @deftypevr {@code{dovecot-configuration} parameter} string log-path
12085 Log file to use for error messages. @samp{syslog} logs to syslog,
12086 @samp{/dev/stderr} logs to stderr.
12087 Defaults to @samp{"syslog"}.
12090 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
12091 Log file to use for informational messages. Defaults to
12093 Defaults to @samp{""}.
12096 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
12097 Log file to use for debug messages. Defaults to
12098 @samp{info-log-path}.
12099 Defaults to @samp{""}.
12102 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
12103 Syslog facility to use if you're logging to syslog. Usually if you
12104 don't want to use @samp{mail}, you'll use local0..local7. Also other
12105 standard facilities are supported.
12106 Defaults to @samp{"mail"}.
12109 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
12110 Log unsuccessful authentication attempts and the reasons why they
12112 Defaults to @samp{#f}.
12115 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
12116 In case of password mismatches, log the attempted password. Valid
12117 values are no, plain and sha1. sha1 can be useful for detecting brute
12118 force password attempts vs. user simply trying the same password over
12119 and over again. You can also truncate the value to n chars by appending
12120 ":n" (e.g. sha1:6).
12121 Defaults to @samp{#f}.
12124 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
12125 Even more verbose logging for debugging purposes. Shows for example
12127 Defaults to @samp{#f}.
12130 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
12131 In case of password mismatches, log the passwords and used scheme so
12132 the problem can be debugged. Enabling this also enables
12134 Defaults to @samp{#f}.
12137 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
12138 Enable mail process debugging. This can help you figure out why
12139 Dovecot isn't finding your mails.
12140 Defaults to @samp{#f}.
12143 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
12144 Show protocol level SSL errors.
12145 Defaults to @samp{#f}.
12148 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
12149 Prefix for each line written to log file. % codes are in
12150 strftime(3) format.
12151 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
12154 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
12155 List of elements we want to log. The elements which have a
12156 non-empty variable value are joined together to form a comma-separated
12160 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
12161 Login log format. %s contains @samp{login-log-format-elements}
12162 string, %$ contains the data we want to log.
12163 Defaults to @samp{"%$: %s"}.
12166 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
12167 Log prefix for mail processes. See doc/wiki/Variables.txt for list
12168 of possible variables you can use.
12169 Defaults to @samp{"\"%s(%u): \""}.
12172 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
12173 Format to use for logging mail deliveries. You can use variables:
12176 Delivery status message (e.g. @samp{saved to INBOX})
12188 Defaults to @samp{"msgid=%m: %$"}.
12191 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
12192 Location for users' mailboxes. The default is empty, which means
12193 that Dovecot tries to find the mailboxes automatically. This won't work
12194 if the user doesn't yet have any mail, so you should explicitly tell
12195 Dovecot the full location.
12197 If you're using mbox, giving a path to the INBOX
12198 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
12199 where the other mailboxes are kept. This is called the "root mail
12200 directory", and it must be the first path given in the
12201 @samp{mail-location} setting.
12203 There are a few special variables you can use, eg.:
12209 user part in user@@domain, same as %u if there's no domain
12211 domain part in user@@domain, empty if there's no domain
12216 See doc/wiki/Variables.txt for full list. Some examples:
12218 @item maildir:~/Maildir
12219 @item mbox:~/mail:INBOX=/var/mail/%u
12220 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
12222 Defaults to @samp{""}.
12225 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
12226 System user and group used to access mails. If you use multiple,
12227 userdb can override these by returning uid or gid fields. You can use
12228 either numbers or names. <doc/wiki/UserIds.txt>.
12229 Defaults to @samp{""}.
12232 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
12234 Defaults to @samp{""}.
12237 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
12238 Group to enable temporarily for privileged operations. Currently
12239 this is used only with INBOX when either its initial creation or
12240 dotlocking fails. Typically this is set to "mail" to give access to
12242 Defaults to @samp{""}.
12245 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
12246 Grant access to these supplementary groups for mail processes.
12247 Typically these are used to set up access to shared mailboxes. Note
12248 that it may be dangerous to set these if users can create
12249 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
12250 could allow a user to delete others' mailboxes, or ln -s
12251 /secret/shared/box ~/mail/mybox would allow reading it).
12252 Defaults to @samp{""}.
12255 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12256 Allow full file system access to clients. There's no access checks
12257 other than what the operating system does for the active UID/GID. It
12258 works with both maildir and mboxes, allowing you to prefix mailboxes
12259 names with e.g. /path/ or ~user/.
12260 Defaults to @samp{#f}.
12263 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12264 Don't use mmap() at all. This is required if you store indexes to
12265 shared file systems (NFS or clustered file system).
12266 Defaults to @samp{#f}.
12269 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12270 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12271 supports @samp{O_EXCL} since version 3, so this should be safe to use
12272 nowadays by default.
12273 Defaults to @samp{#t}.
12276 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12277 When to use fsync() or fdatasync() calls:
12280 Whenever necessary to avoid losing important data
12282 Useful with e.g. NFS when write()s are delayed
12284 Never use it (best performance, but crashes can lose data).
12286 Defaults to @samp{"optimized"}.
12289 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12290 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12291 NFS caches whenever needed. If you're using only a single mail server
12293 Defaults to @samp{#f}.
12296 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12297 Mail index files also exist in NFS. Setting this to yes requires
12298 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12299 Defaults to @samp{#f}.
12302 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12303 Locking method for index files. Alternatives are fcntl, flock and
12304 dotlock. Dotlocking uses some tricks which may create more disk I/O
12305 than other locking methods. NFS users: flock doesn't work, remember to
12306 change @samp{mmap-disable}.
12307 Defaults to @samp{"fcntl"}.
12310 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12311 Directory in which LDA/LMTP temporarily stores incoming mails >128
12313 Defaults to @samp{"/tmp"}.
12316 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12317 Valid UID range for users. This is mostly to make sure that users can't
12318 log in as daemons or other system users. Note that denying root logins is
12319 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12321 Defaults to @samp{500}.
12324 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12326 Defaults to @samp{0}.
12329 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12330 Valid GID range for users. Users having non-valid GID as primary group ID
12331 aren't allowed to log in. If user belongs to supplementary groups with
12332 non-valid GIDs, those groups are not set.
12333 Defaults to @samp{1}.
12336 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12338 Defaults to @samp{0}.
12341 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12342 Maximum allowed length for mail keyword name. It's only forced when
12343 trying to create new keywords.
12344 Defaults to @samp{50}.
12347 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12348 List of directories under which chrooting is allowed for mail
12349 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12350 too). This setting doesn't affect @samp{login-chroot}
12351 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12352 "/./" in home dirs are ignored. WARNING: Never add directories here
12353 which local users can modify, that may lead to root exploit. Usually
12354 this should be done only if you don't allow shell access for users.
12355 <doc/wiki/Chrooting.txt>.
12356 Defaults to @samp{()}.
12359 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12360 Default chroot directory for mail processes. This can be overridden
12361 for specific users in user database by giving /./ in user's home
12362 directory (e.g. /home/./user chroots into /home). Note that usually
12363 there is no real need to do chrooting, Dovecot doesn't allow users to
12364 access files outside their mail directory anyway. If your home
12365 directories are prefixed with the chroot directory, append "/." to
12366 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12367 Defaults to @samp{""}.
12370 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12371 UNIX socket path to master authentication server to find users.
12372 This is used by imap (for shared users) and lda.
12373 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12376 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12377 Directory where to look up mail plugins.
12378 Defaults to @samp{"/usr/lib/dovecot"}.
12381 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12382 List of plugins to load for all services. Plugins specific to IMAP,
12383 LDA, etc. are added to this list in their own .conf files.
12384 Defaults to @samp{()}.
12387 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12388 The minimum number of mails in a mailbox before updates are done to
12389 cache file. This allows optimizing Dovecot's behavior to do less disk
12390 writes at the cost of more disk reads.
12391 Defaults to @samp{0}.
12394 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12395 When IDLE command is running, mailbox is checked once in a while to
12396 see if there are any new mails or other changes. This setting defines
12397 the minimum time to wait between those checks. Dovecot can also use
12398 dnotify, inotify and kqueue to find out immediately when changes
12400 Defaults to @samp{"30 secs"}.
12403 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12404 Save mails with CR+LF instead of plain LF. This makes sending those
12405 mails take less CPU, especially with sendfile() syscall with Linux and
12406 FreeBSD. But it also creates a bit more disk I/O which may just make it
12407 slower. Also note that if other software reads the mboxes/maildirs,
12408 they may handle the extra CRs wrong and cause problems.
12409 Defaults to @samp{#f}.
12412 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12413 By default LIST command returns all entries in maildir beginning
12414 with a dot. Enabling this option makes Dovecot return only entries
12415 which are directories. This is done by stat()ing each entry, so it
12416 causes more disk I/O.
12417 (For systems setting struct @samp{dirent->d_type} this check is free
12418 and it's done always regardless of this setting).
12419 Defaults to @samp{#f}.
12422 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12423 When copying a message, do it with hard links whenever possible.
12424 This makes the performance much better, and it's unlikely to have any
12426 Defaults to @samp{#t}.
12429 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12430 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12431 directory only when its mtime changes unexpectedly or when we can't find
12432 the mail otherwise.
12433 Defaults to @samp{#f}.
12436 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12437 Which locking methods to use for locking mbox. There are four
12442 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12443 solution. If you want to use /var/mail/ like directory, the users will
12444 need write access to that directory.
12446 Same as dotlock, but if it fails because of permissions or because there
12447 isn't enough disk space, just skip it.
12449 Use this if possible. Works with NFS too if lockd is used.
12451 May not exist in all systems. Doesn't work with NFS.
12453 May not exist in all systems. Doesn't work with NFS.
12456 You can use multiple locking methods; if you do the order they're declared
12457 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12458 locking methods as well. Some operating systems don't allow using some of
12459 them simultaneously.
12462 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12466 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12467 Maximum time to wait for lock (all of them) before aborting.
12468 Defaults to @samp{"5 mins"}.
12471 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12472 If dotlock exists but the mailbox isn't modified in any way,
12473 override the lock file after this much time.
12474 Defaults to @samp{"2 mins"}.
12477 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12478 When mbox changes unexpectedly we have to fully read it to find out
12479 what changed. If the mbox is large this can take a long time. Since
12480 the change is usually just a newly appended mail, it'd be faster to
12481 simply read the new mails. If this setting is enabled, Dovecot does
12482 this but still safely fallbacks to re-reading the whole mbox file
12483 whenever something in mbox isn't how it's expected to be. The only real
12484 downside to this setting is that if some other MUA changes message
12485 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12486 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12487 Defaults to @samp{#t}.
12490 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12491 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12492 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12493 @samp{mbox-dirty-syncs} is ignored.
12494 Defaults to @samp{#f}.
12497 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12498 Delay writing mbox headers until doing a full write sync (EXPUNGE
12499 and CHECK commands and when closing the mailbox). This is especially
12500 useful for POP3 where clients often delete all mails. The downside is
12501 that our changes aren't immediately visible to other MUAs.
12502 Defaults to @samp{#t}.
12505 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12506 If mbox size is smaller than this (e.g. 100k), don't write index
12507 files. If an index file already exists it's still read, just not
12509 Defaults to @samp{0}.
12512 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12513 Maximum dbox file size until it's rotated.
12514 Defaults to @samp{2000000}.
12517 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12518 Maximum dbox file age until it's rotated. Typically in days. Day
12519 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12521 Defaults to @samp{"1d"}.
12524 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12525 When creating new mdbox files, immediately preallocate their size to
12526 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12527 with some file systems (ext4, xfs).
12528 Defaults to @samp{#f}.
12531 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12532 sdbox and mdbox support saving mail attachments to external files,
12533 which also allows single instance storage for them. Other backends
12534 don't support this for now.
12536 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12538 Directory root where to store mail attachments. Disabled, if empty.
12539 Defaults to @samp{""}.
12542 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12543 Attachments smaller than this aren't saved externally. It's also
12544 possible to write a plugin to disable saving specific attachments
12546 Defaults to @samp{128000}.
12549 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12550 File system backend to use for saving attachments:
12553 No SiS done by Dovecot (but this might help FS's own deduplication)
12555 SiS with immediate byte-by-byte comparison during saving
12556 @item sis-queue posix
12557 SiS with delayed comparison and deduplication.
12559 Defaults to @samp{"sis posix"}.
12562 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
12563 Hash format to use in attachment filenames. You can add any text and
12564 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
12565 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
12566 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
12567 Defaults to @samp{"%@{sha1@}"}.
12570 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
12572 Defaults to @samp{100}.
12575 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
12577 Defaults to @samp{1000}.
12580 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
12581 Default VSZ (virtual memory size) limit for service processes.
12582 This is mainly intended to catch and kill processes that leak memory
12583 before they eat up everything.
12584 Defaults to @samp{256000000}.
12587 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
12588 Login user is internally used by login processes. This is the most
12589 untrusted user in Dovecot system. It shouldn't have access to anything
12591 Defaults to @samp{"dovenull"}.
12594 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
12595 Internal user is used by unprivileged processes. It should be
12596 separate from login user, so that login processes can't disturb other
12598 Defaults to @samp{"dovecot"}.
12601 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
12602 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
12603 Defaults to @samp{"required"}.
12606 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
12607 PEM encoded X.509 SSL/TLS certificate (public key).
12608 Defaults to @samp{"</etc/dovecot/default.pem"}.
12611 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
12612 PEM encoded SSL/TLS private key. The key is opened before
12613 dropping root privileges, so keep the key file unreadable by anyone but
12615 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
12618 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
12619 If key file is password protected, give the password here.
12620 Alternatively give it when starting dovecot with -p parameter. Since
12621 this file is often world-readable, you may want to place this setting
12622 instead to a different.
12623 Defaults to @samp{""}.
12626 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
12627 PEM encoded trusted certificate authority. Set this only if you
12628 intend to use @samp{ssl-verify-client-cert? #t}. The file should
12629 contain the CA certificate(s) followed by the matching
12630 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
12631 Defaults to @samp{""}.
12634 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
12635 Require that CRL check succeeds for client certificates.
12636 Defaults to @samp{#t}.
12639 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
12640 Request client to send a certificate. If you also want to require
12641 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
12642 Defaults to @samp{#f}.
12645 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
12646 Which field from certificate to use for username. commonName and
12647 x500UniqueIdentifier are the usual choices. You'll also need to set
12648 @samp{auth-ssl-username-from-cert? #t}.
12649 Defaults to @samp{"commonName"}.
12652 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
12653 How often to regenerate the SSL parameters file. Generation is
12654 quite CPU intensive operation. The value is in hours, 0 disables
12655 regeneration entirely.
12656 Defaults to @samp{168}.
12659 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
12660 SSL protocols to use.
12661 Defaults to @samp{"!SSLv2"}.
12664 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
12665 SSL ciphers to use.
12666 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
12669 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
12670 SSL crypto device to use, for valid values run "openssl engine".
12671 Defaults to @samp{""}.
12674 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
12675 Address to use when sending rejection mails.
12676 %d expands to recipient domain.
12677 Defaults to @samp{"postmaster@@%d"}.
12680 @deftypevr {@code{dovecot-configuration} parameter} string hostname
12681 Hostname to use in various parts of sent mails (e.g. in Message-Id)
12682 and in LMTP replies. Default is the system's real hostname@@domain.
12683 Defaults to @samp{""}.
12686 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
12687 If user is over quota, return with temporary failure instead of
12689 Defaults to @samp{#f}.
12692 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
12693 Binary to use for sending mails.
12694 Defaults to @samp{"/usr/sbin/sendmail"}.
12697 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
12698 If non-empty, send mails via this SMTP host[:port] instead of
12700 Defaults to @samp{""}.
12703 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
12704 Subject: header to use for rejection mails. You can use the same
12705 variables as for @samp{rejection-reason} below.
12706 Defaults to @samp{"Rejected: %s"}.
12709 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
12710 Human readable error message for rejection mails. You can use
12723 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
12726 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
12727 Delimiter character between local-part and detail in email
12729 Defaults to @samp{"+"}.
12732 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
12733 Header where the original recipient address (SMTP's RCPT TO:
12734 address) is taken from if not available elsewhere. With dovecot-lda -a
12735 parameter overrides this. A commonly used header for this is
12737 Defaults to @samp{""}.
12740 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
12741 Should saving a mail to a nonexistent mailbox automatically create
12743 Defaults to @samp{#f}.
12746 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
12747 Should automatically created mailboxes be also automatically
12749 Defaults to @samp{#f}.
12752 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
12753 Maximum IMAP command line length. Some clients generate very long
12754 command lines with huge mailboxes, so you may need to raise this if you
12755 get "Too long argument" or "IMAP command line too large" errors
12757 Defaults to @samp{64000}.
12760 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
12761 IMAP logout format string:
12764 total number of bytes read from client
12766 total number of bytes sent to client.
12768 Defaults to @samp{"in=%i out=%o"}.
12771 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
12772 Override the IMAP CAPABILITY response. If the value begins with '+',
12773 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
12774 Defaults to @samp{""}.
12777 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
12778 How long to wait between "OK Still here" notifications when client
12780 Defaults to @samp{"2 mins"}.
12783 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
12784 ID field names and values to send to clients. Using * as the value
12785 makes Dovecot use the default value. The following fields have default
12786 values currently: name, version, os, os-version, support-url,
12788 Defaults to @samp{""}.
12791 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
12792 ID fields sent by client to log. * means everything.
12793 Defaults to @samp{""}.
12796 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
12797 Workarounds for various client bugs:
12800 @item delay-newmail
12801 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
12802 CHECK commands. Some clients ignore them otherwise, for example OSX
12803 Mail (<v2.1). Outlook Express breaks more badly though, without this it
12804 may show user "Message no longer in server" errors. Note that OE6
12805 still breaks even with this workaround if synchronization is set to
12808 @item tb-extra-mailbox-sep
12809 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
12810 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
12811 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
12813 @item tb-lsub-flags
12814 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
12815 This makes Thunderbird realize they aren't selectable and show them
12816 greyed out, instead of only later giving "not selectable" popup error.
12818 Defaults to @samp{()}.
12821 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
12822 Host allowed in URLAUTH URLs sent by client. "*" allows all.
12823 Defaults to @samp{""}.
12827 Whew! Lots of configuration options. The nice thing about it though is
12828 that GuixSD has a complete interface to Dovecot's configuration
12829 language. This allows not only a nice way to declare configurations,
12830 but also offers reflective capabilities as well: users can write code to
12831 inspect and transform configurations from within Scheme.
12833 However, it could be that you just want to get a @code{dovecot.conf} up
12834 and running. In that case, you can pass an
12835 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
12836 @code{dovecot-service}. As its name indicates, an opaque configuration
12837 does not have easy reflective capabilities.
12839 Available @code{opaque-dovecot-configuration} fields are:
12841 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
12842 The dovecot package.
12845 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
12846 The contents of the @code{dovecot.conf}, as a string.
12849 For example, if your @code{dovecot.conf} is just the empty string, you
12850 could instantiate a dovecot service like this:
12853 (dovecot-service #:config
12854 (opaque-dovecot-configuration
12858 @subsubheading OpenSMTPD Service
12860 @deffn {Scheme Variable} opensmtpd-service-type
12861 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
12862 service, whose value should be an @code{opensmtpd-configuration} object
12863 as in this example:
12866 (service opensmtpd-service-type
12867 (opensmtpd-configuration
12868 (config-file (local-file "./my-smtpd.conf"))))
12872 @deftp {Data Type} opensmtpd-configuration
12873 Data type representing the configuration of opensmtpd.
12876 @item @code{package} (default: @var{opensmtpd})
12877 Package object of the OpenSMTPD SMTP server.
12879 @item @code{config-file} (default: @var{%default-opensmtpd-file})
12880 File-like object of the OpenSMTPD configuration file to use. By default
12881 it listens on the loopback network interface, and allows for mail from
12882 users and daemons on the local machine, as well as permitting email to
12883 remote servers. Run @command{man smtpd.conf} for more information.
12888 @subsubheading Exim Service
12890 @cindex mail transfer agent (MTA)
12891 @cindex MTA (mail transfer agent)
12894 @deffn {Scheme Variable} exim-service-type
12895 This is the type of the @uref{https://exim.org, Exim} mail transfer
12896 agent (MTA), whose value should be an @code{exim-configuration} object
12897 as in this example:
12900 (service exim-service-type
12901 (exim-configuration
12902 (config-file (local-file "./my-exim.conf"))))
12906 In order to use an @code{exim-service-type} service you must also have a
12907 @code{mail-aliases-service-type} service present in your
12908 @code{operating-system} (even if it has no aliases).
12910 @deftp {Data Type} exim-configuration
12911 Data type representing the configuration of exim.
12914 @item @code{package} (default: @var{exim})
12915 Package object of the Exim server.
12917 @item @code{config-file} (default: @code{#f})
12918 File-like object of the Exim configuration file to use. If its value is
12919 @code{#f} then use the default configuration file from the package
12920 provided in @code{package}. The resulting configuration file is loaded
12921 after setting the @code{exim_user} and @code{exim_group} configuration
12927 @subsubheading Mail Aliases Service
12929 @cindex email aliases
12930 @cindex aliases, for email addresses
12932 @deffn {Scheme Variable} mail-aliases-service-type
12933 This is the type of the service which provides @code{/etc/aliases},
12934 specifying how to deliver mail to users on this system.
12937 (service mail-aliases-service-type
12938 '(("postmaster" "bob")
12939 ("bob" "bob@@example.com" "bob@@example2.com")))
12943 The configuration for a @code{mail-aliases-service-type} service is an
12944 association list denoting how to deliver mail that comes to this
12945 system. Each entry is of the form @code{(alias addresses ...)}, with
12946 @code{alias} specifying the local alias and @code{addresses} specifying
12947 where to deliver this user's mail.
12949 The aliases aren't required to exist as users on the local system. In
12950 the above example, there doesn't need to be a @code{postmaster} entry in
12951 the @code{operating-system}'s @code{user-accounts} in order to deliver
12952 the @code{postmaster} mail to @code{bob} (which subsequently would
12953 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
12955 @node Messaging Services
12956 @subsubsection Messaging Services
12961 The @code{(gnu services messaging)} module provides Guix service
12962 definitions for messaging services: currently only Prosody is supported.
12964 @subsubheading Prosody Service
12966 @deffn {Scheme Variable} prosody-service-type
12967 This is the type for the @uref{http://prosody.im, Prosody XMPP
12968 communication server}. Its value must be a @code{prosody-configuration}
12969 record as in this example:
12972 (service prosody-service-type
12973 (prosody-configuration
12974 (modules-enabled (cons "groups" %default-modules-enabled))
12977 (int-component-configuration
12978 (hostname "conference.example.net")
12980 (mod-muc (mod-muc-configuration)))))
12983 (virtualhost-configuration
12984 (domain "example.net"))))))
12987 See below for details about @code{prosody-configuration}.
12991 By default, Prosody does not need much configuration. Only one
12992 @code{virtualhosts} field is needed: it specifies the domain you wish
12995 Prosodyctl will help you generate X.509 certificates and keys:
12998 prosodyctl cert request example.net
13001 The available configuration parameters follow. Each parameter
13002 definition is preceded by its type; for example, @samp{string-list foo}
13003 indicates that the @code{foo} parameter should be specified as a list of
13004 strings. Types starting with @code{maybe-} denote parameters that won't
13005 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
13007 There is also a way to specify the configuration as a string, if you
13008 have an old @code{prosody.cfg.lua} file that you want to port over from
13009 some other system; see the end for more details.
13011 @c The following documentation was initially generated by
13012 @c (generate-documentation) in (gnu services messaging). Manually maintained
13013 @c documentation is better, so we shouldn't hesitate to edit below as
13014 @c needed. However if the change you want to make to this documentation
13015 @c can be done in an automated way, it's probably easier to change
13016 @c (generate-documentation) than to make it below and have to deal with
13017 @c the churn as Prosody updates.
13019 Available @code{prosody-configuration} fields are:
13021 @deftypevr {@code{prosody-configuration} parameter} package prosody
13022 The Prosody package.
13025 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
13026 Location of the Prosody data storage directory. See
13027 @url{http://prosody.im/doc/configure}.
13028 Defaults to @samp{"/var/lib/prosody"}.
13031 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
13032 Additional plugin directories. They are searched in all the specified
13033 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
13034 Defaults to @samp{()}.
13037 @deftypevr {@code{prosody-configuration} parameter} string-list admins
13038 This is a list of accounts that are admins for the server. Note that you
13039 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
13040 @url{http://prosody.im/doc/creating_accounts}.
13041 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
13042 Defaults to @samp{()}.
13045 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
13046 Enable use of libevent for better performance under high load. See
13047 @url{http://prosody.im/doc/libevent}.
13048 Defaults to @samp{#f}.
13051 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
13052 This is the list of modules Prosody will load on startup. It looks for
13053 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
13054 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
13055 Defaults to @samp{%default-modules-enabled}.
13058 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
13059 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
13060 should you want to disable them then add them to this list.
13061 Defaults to @samp{()}.
13064 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
13065 Path to a text file where the shared groups are defined. If this path is
13066 empty then @samp{mod_groups} does nothing. See
13067 @url{http://prosody.im/doc/modules/mod_groups}.
13068 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
13071 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
13072 Disable account creation by default, for security. See
13073 @url{http://prosody.im/doc/creating_accounts}.
13074 Defaults to @samp{#f}.
13077 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
13078 These are the SSL/TLS-related settings. Most of them are disabled so to
13079 use Prosody's defaults. If you do not completely understand these options, do
13080 not add them to your config, it is easy to lower the security of your server
13081 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
13083 Available @code{ssl-configuration} fields are:
13085 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
13086 This determines what handshake to use.
13089 @deftypevr {@code{ssl-configuration} parameter} file-name key
13090 Path to your private key file, relative to @code{/etc/prosody}.
13091 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
13094 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
13095 Path to your certificate file, relative to @code{/etc/prosody}.
13096 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
13099 @deftypevr {@code{ssl-configuration} parameter} file-name capath
13100 Path to directory containing root certificates that you wish Prosody to
13101 trust when verifying the certificates of remote servers.
13102 Defaults to @samp{"/etc/ssl/certs"}.
13105 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
13106 Path to a file containing root certificates that you wish Prosody to trust.
13107 Similar to @code{capath} but with all certificates concatenated together.
13110 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
13111 A list of verification options (these mostly map to OpenSSL's
13112 @code{set_verify()} flags).
13115 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
13116 A list of general options relating to SSL/TLS. These map to OpenSSL's
13117 @code{set_options()}. For a full list of options available in LuaSec, see the
13121 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
13122 How long a chain of certificate authorities to check when looking for a
13123 trusted root certificate.
13126 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
13127 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
13128 clients, and in what order.
13131 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
13132 A path to a file containing parameters for Diffie-Hellman key exchange. You
13133 can create such a file with:
13134 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
13137 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
13138 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
13139 @samp{"secp384r1"}.
13142 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
13143 A list of "extra" verification options.
13146 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
13147 Password for encrypted private keys.
13152 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
13153 Whether to force all client-to-server connections to be encrypted or not.
13154 See @url{http://prosody.im/doc/modules/mod_tls}.
13155 Defaults to @samp{#f}.
13158 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
13159 Whether to force all server-to-server connections to be encrypted or not.
13160 See @url{http://prosody.im/doc/modules/mod_tls}.
13161 Defaults to @samp{#f}.
13164 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
13165 Whether to require encryption and certificate authentication. This
13166 provides ideal security, but requires servers you communicate with to support
13167 encryption AND present valid, trusted certificates. See
13168 @url{http://prosody.im/doc/s2s#security}.
13169 Defaults to @samp{#f}.
13172 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
13173 Many servers don't support encryption or have invalid or self-signed
13174 certificates. You can list domains here that will not be required to
13175 authenticate using certificates. They will be authenticated using DNS. See
13176 @url{http://prosody.im/doc/s2s#security}.
13177 Defaults to @samp{()}.
13180 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
13181 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
13182 valid certificates for some domains by specifying a list here. See
13183 @url{http://prosody.im/doc/s2s#security}.
13184 Defaults to @samp{()}.
13187 @deftypevr {@code{prosody-configuration} parameter} string authentication
13188 Select the authentication backend to use. The default provider stores
13189 passwords in plaintext and uses Prosody's configured data storage to store the
13190 authentication data. If you do not trust your server please see
13191 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
13192 about using the hashed backend. See also
13193 @url{http://prosody.im/doc/authentication}
13194 Defaults to @samp{"internal_plain"}.
13197 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
13198 Set logging options. Advanced logging configuration is not yet supported
13199 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
13200 Defaults to @samp{"*syslog"}.
13203 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
13204 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
13205 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
13208 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
13209 A host in Prosody is a domain on which user accounts can be created. For
13210 example if you want your users to have addresses like
13211 @samp{"john.smith@@example.com"} then you need to add a host
13212 @samp{"example.com"}. All options in this list will apply only to this host.
13214 Note: the name "virtual" host is used in configuration to avoid confusion with
13215 the actual physical host that Prosody is installed on. A single Prosody
13216 instance can serve many domains, each one defined as a VirtualHost entry in
13217 Prosody's configuration. Conversely a server that hosts a single domain would
13218 have just one VirtualHost entry.
13220 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
13222 Available @code{virtualhost-configuration} fields are:
13224 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:
13225 @deftypevr {@code{virtualhost-configuration} parameter} string domain
13226 Domain you wish Prosody to serve.
13231 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
13232 Components are extra services on a server which are available to clients,
13233 usually on a subdomain of the main server (such as
13234 @samp{"mycomponent.example.com"}). Example components might be chatroom
13235 servers, user directories, or gateways to other protocols.
13237 Internal components are implemented with Prosody-specific plugins. To add an
13238 internal component, you simply fill the hostname field, and the plugin you wish
13239 to use for the component.
13241 See @url{http://prosody.im/doc/components}.
13242 Defaults to @samp{()}.
13244 Available @code{int-component-configuration} fields are:
13246 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:
13247 @deftypevr {@code{int-component-configuration} parameter} string hostname
13248 Hostname of the component.
13251 @deftypevr {@code{int-component-configuration} parameter} string plugin
13252 Plugin you wish to use for the component.
13255 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
13256 Multi-user chat (MUC) is Prosody's module for allowing you to create
13257 hosted chatrooms/conferences for XMPP users.
13259 General information on setting up and using multi-user chatrooms can be found
13260 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
13261 which you should read if you are new to XMPP chatrooms.
13263 See also @url{http://prosody.im/doc/modules/mod_muc}.
13265 Available @code{mod-muc-configuration} fields are:
13267 @deftypevr {@code{mod-muc-configuration} parameter} string name
13268 The name to return in service discovery responses.
13269 Defaults to @samp{"Prosody Chatrooms"}.
13272 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
13273 If @samp{#t}, this will only allow admins to create new chatrooms.
13274 Otherwise anyone can create a room. The value @samp{"local"} restricts room
13275 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
13276 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
13277 restricts to service administrators only.
13278 Defaults to @samp{#f}.
13281 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
13282 Maximum number of history messages that will be sent to the member that has
13283 just joined the room.
13284 Defaults to @samp{20}.
13291 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13292 External components use XEP-0114, which most standalone components
13293 support. To add an external component, you simply fill the hostname field. See
13294 @url{http://prosody.im/doc/components}.
13295 Defaults to @samp{()}.
13297 Available @code{ext-component-configuration} fields are:
13299 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:
13300 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13301 Password which the component will use to log in.
13304 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13305 Hostname of the component.
13310 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13311 Port(s) Prosody listens on for component connections.
13314 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13315 Interface Prosody listens on for component connections.
13316 Defaults to @samp{"127.0.0.1"}.
13319 It could be that you just want to get a @code{prosody.cfg.lua}
13320 up and running. In that case, you can pass an
13321 @code{opaque-prosody-configuration} record as the value of
13322 @code{prosody-service-type}. As its name indicates, an opaque configuration
13323 does not have easy reflective capabilities.
13324 Available @code{opaque-prosody-configuration} fields are:
13326 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13327 The prosody package.
13330 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13331 The contents of the @code{prosody.cfg.lua} to use.
13334 For example, if your @code{prosody.cfg.lua} is just the empty
13335 string, you could instantiate a prosody service like this:
13338 (service prosody-service-type
13339 (opaque-prosody-configuration
13340 (prosody.cfg.lua "")))
13343 @node Kerberos Services
13344 @subsubsection Kerberos Services
13347 The @code{(gnu services kerberos)} module provides services relating to
13348 the authentication protocol @dfn{Kerberos}.
13350 @subsubheading Krb5 Service
13352 Programs using a Kerberos client library normally
13353 expect a configuration file in @file{/etc/krb5.conf}.
13354 This service generates such a file from a definition provided in the
13355 operating system declaration.
13356 It does not cause any daemon to be started.
13358 No ``keytab'' files are provided by this service---you must explicitly create them.
13359 This service is known to work with the MIT client library, @code{mit-krb5}.
13360 Other implementations have not been tested.
13362 @defvr {Scheme Variable} krb5-service-type
13363 A service type for Kerberos 5 clients.
13367 Here is an example of its use:
13369 (service krb5-service-type
13370 (krb5-configuration
13371 (default-realm "EXAMPLE.COM")
13372 (allow-weak-crypto? #t)
13375 (name "EXAMPLE.COM")
13376 (admin-server "groucho.example.com")
13377 (kdc "karl.example.com"))
13380 (admin-server "kerb-admin.argrx.edu")
13381 (kdc "keys.argrx.edu"))))))
13385 This example provides a Kerberos@tie{}5 client configuration which:
13387 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13388 of which have distinct administration servers and key distribution centers;
13389 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13390 specified by clients;
13391 @item Accepts services which only support encryption types known to be weak.
13394 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13395 Only the most commonly used ones are described here.
13396 For a full list, and more detailed explanation of each, see the MIT
13397 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13401 @deftp {Data Type} krb5-realm
13402 @cindex realm, kerberos
13405 This field is a string identifying the name of the realm.
13406 A common convention is to use the fully qualified DNS name of your organization,
13407 converted to upper case.
13409 @item @code{admin-server}
13410 This field is a string identifying the host where the administration server is
13414 This field is a string identifying the key distribution center
13419 @deftp {Data Type} krb5-configuration
13422 @item @code{allow-weak-crypto?} (default: @code{#f})
13423 If this flag is @code{#t} then services which only offer encryption algorithms
13424 known to be weak will be accepted.
13426 @item @code{default-realm} (default: @code{#f})
13427 This field should be a string identifying the default Kerberos
13428 realm for the client.
13429 You should set this field to the name of your Kerberos realm.
13430 If this value is @code{#f}
13431 then a realm must be specified with every Kerberos principal when invoking programs
13432 such as @command{kinit}.
13434 @item @code{realms}
13435 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13437 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13443 @subsubheading PAM krb5 Service
13446 The @code{pam-krb5} service allows for login authentication and password
13447 management via Kerberos.
13448 You will need this service if you want PAM enabled applications to authenticate
13449 users using Kerberos.
13451 @defvr {Scheme Variable} pam-krb5-service-type
13452 A service type for the Kerberos 5 PAM module.
13455 @deftp {Data Type} pam-krb5-configuration
13456 Data type representing the configuration of the Kerberos 5 PAM module
13457 This type has the following parameters:
13459 @item @code{pam-krb5} (default: @code{pam-krb5})
13460 The pam-krb5 package to use.
13462 @item @code{minimum-uid} (default: @code{1000})
13463 The smallest user ID for which Kerberos authentications should be attempted.
13464 Local accounts with lower values will silently fail to authenticate.
13470 @subsubsection Web Services
13475 The @code{(gnu services web)} module provides the following service:
13477 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
13478 [#:log-directory ``/var/log/nginx''] @
13479 [#:run-directory ``/var/run/nginx''] @
13480 [#:server-list '()] @
13481 [#:upstream-list '()] @
13482 [#:config-file @code{#f}]
13484 Return a service that runs @var{nginx}, the nginx web server.
13486 The nginx daemon loads its runtime configuration from @var{config-file}.
13487 Log files are written to @var{log-directory} and temporary runtime data
13488 files are written to @var{run-directory}. For proper operation, these
13489 arguments should match what is in @var{config-file} to ensure that the
13490 directories are created when the service is activated.
13492 As an alternative to using a @var{config-file}, @var{server-list} can be
13493 used to specify the list of @dfn{server blocks} required on the host and
13494 @var{upstream-list} can be used to specify a list of @dfn{upstream
13495 blocks} to configure. For this to work, use the default value for
13498 At startup, @command{nginx} has not yet read its configuration file, so it
13499 uses a default file to log error messages. If it fails to load its
13500 configuration file, that is where error messages are logged. After the
13501 configuration file is loaded, the default error log file changes as per
13502 configuration. In our case, startup error messages can be found in
13503 @file{/var/run/nginx/logs/error.log}, and after configuration in
13504 @file{/var/log/nginx/error.log}. The second location can be changed with the
13505 @var{log-directory} configuration option.
13509 @deffn {Scheme Variable} nginx-service-type
13510 This is type for the nginx web server.
13512 This service can be extended to add server blocks in addition to the
13513 default one, as in this example:
13516 (simple-service 'my-extra-server nginx-service-type
13517 (list (nginx-server-configuration
13519 (root "/srv/http/extra-website"))))
13523 @deftp {Data Type} nginx-server-configuration
13524 Data type representing the configuration of an nginx server block.
13525 This type has the following parameters:
13528 @item @code{http-port} (default: @code{80})
13529 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
13530 nginx should not listen for HTTP (non secure) connection for this
13531 @dfn{server block}.
13533 @item @code{https-port} (default: @code{443})
13534 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
13535 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
13537 Note that nginx can listen for HTTP and HTTPS connections in the same
13538 @dfn{server block}.
13540 @item @code{server-name} (default: @code{(list 'default)})
13541 A list of server names this server represents. @code{'default} represents the
13542 default server for connections matching no other server.
13544 @item @code{root} (default: @code{"/srv/http"})
13545 Root of the website nginx will serve.
13547 @item @code{locations} (default: @code{'()})
13548 A list of @dfn{nginx-location-configuration} or
13549 @dfn{nginx-named-location-configuration} records to use within this
13552 @item @code{index} (default: @code{(list "index.html")})
13553 Index files to look for when clients ask for a directory. If it cannot be found,
13554 Nginx will send the list of files in the directory.
13556 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
13557 Where to find the certificate for secure connections. Set it to @code{#f} if
13558 you don't have a certificate or you don't want to use HTTPS.
13560 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
13561 Where to find the private key for secure connections. Set it to @code{#f} if
13562 you don't have a key or you don't want to use HTTPS.
13564 @item @code{server-tokens?} (default: @code{#f})
13565 Whether the server should add its configuration to response.
13570 @deftp {Data Type} nginx-upstream-configuration
13571 Data type representing the configuration of an nginx @code{upstream}
13572 block. This type has the following parameters:
13576 Name for this group of servers.
13578 @item @code{servers}
13579 Specify the addresses of the servers in the group. The address can be
13580 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
13581 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
13582 prefix @samp{unix:}. For addresses using an IP address or domain name,
13583 the default port is 80, and a different port can be specified
13589 @deftp {Data Type} nginx-location-configuration
13590 Data type representing the configuration of an nginx @code{location}
13591 block. This type has the following parameters:
13595 URI which this location block matches.
13597 @anchor{nginx-location-configuration body}
13599 Body of the location block, specified as a string. This can contain many
13600 configuration directives. For example, to pass requests to a upstream
13601 server group defined using an @code{nginx-upstream-configuration} block,
13602 the following directive would be specified in the body @samp{proxy_pass
13603 http://upstream-name;}.
13608 @deftp {Data Type} nginx-named-location-configuration
13609 Data type representing the configuration of an nginx named location
13610 block. Named location blocks are used for request redirection, and not
13611 used for regular request processing. This type has the following
13616 Name to identify this location block.
13619 @xref{nginx-location-configuration body}, as the body for named location
13620 blocks can be used in a similar way to the
13621 @code{nginx-location-configuration body}. One restriction is that the
13622 body of a named location block cannot contain location blocks.
13629 @subsubsection DNS Services
13630 @cindex DNS (domain name system)
13631 @cindex domain name system (DNS)
13633 The @code{(gnu services dns)} module provides services related to the
13634 @dfn{domain name system} (DNS). It provides a server service for hosting
13635 an @emph{authoritative} DNS server for multiple zones, slave or master.
13636 This service uses @uref{https://www.knot-dns.cz/, Knot DNS}.
13638 An example configuration of an authoritative server for two zones, one master
13642 (define-zone-entries example.org.zone
13643 ;; Name TTL Class Type Data
13644 ("@@" "" "IN" "A" "127.0.0.1")
13645 ("@@" "" "IN" "NS" "ns")
13646 ("ns" "" "IN" "A" "127.0.0.1"))
13648 (define master-zone
13649 (knot-zone-configuration
13650 (domain "example.org")
13652 (origin "example.org")
13653 (entries example.org.zone)))))
13656 (knot-zone-configuration
13657 (domain "plop.org")
13658 (dnssec-policy "default")
13659 (master (list "plop-master"))))
13661 (define plop-master
13662 (knot-remote-configuration
13664 (address (list "208.76.58.171"))))
13668 (services (cons* (service knot-service-type
13669 (knot-confifguration
13670 (remotes (list plop-master))
13671 (zones (list master-zone slave-zone))))
13676 @deffn {Scheme Variable} knot-service-type
13677 This is the type for the Knot DNS server.
13679 Knot DNS is an authoritative DNS server, meaning that it can serve multiple
13680 zones, that is to say domain names you would buy from a registrar. This server
13681 is not a resolver, meaning that it can only resolve names for which it is
13682 authoritative. This server can be configured to serve zones as a master server
13683 or a slave server as a per-zone basis. Slave zones will get their data from
13684 masters, and will serve it as an authoritative server. From the point of view
13685 of a resolver, there is no difference between master and slave.
13687 The following data types are used to configure the Knot DNS server:
13690 @deftp {Data Type} knot-key-configuration
13691 Data type representing a key.
13692 This type has the following parameters:
13695 @item @code{id} (default: @code{""})
13696 An identifier for other configuration fields to refer to this key. IDs must
13697 be unique and must not be empty.
13699 @item @code{algorithm} (default: @code{#f})
13700 The algorithm to use. Choose between @code{#f}, @code{'hmac-md5},
13701 @code{'hmac-sha1}, @code{'hmac-sha224}, @code{'hmac-sha256}, @code{'hmac-sha384}
13702 and @code{'hmac-sha512}.
13704 @item @code{secret} (default: @code{""})
13705 The secret key itself.
13710 @deftp {Data Type} knot-acl-configuration
13711 Data type representing an Access Control List (ACL) configuration.
13712 This type has the following parameters:
13715 @item @code{id} (default: @code{""})
13716 An identifier for ether configuration fields to refer to this key. IDs must be
13717 unique and must not be empty.
13719 @item @code{address} (default: @code{'()})
13720 An ordered list of IP addresses, network subnets, or network ranges represented
13721 with strings. The query must match one of them. Empty value means that
13722 address match is not required.
13724 @item @code{key} (default: @code{'()})
13725 An ordered list of references to keys represented with strings. The string
13726 must match a key ID defined in a @code{knot-key-configuration}. No key means
13727 that a key is not require to match that ACL.
13729 @item @code{action} (default: @code{'()})
13730 An ordered list of actions that are permitted or forbidden by this ACL. Possible
13731 values are lists of zero or more elements from @code{'transfer}, @code{'notify}
13732 and @code{'update}.
13734 @item @code{deny?} (default: @code{#f})
13735 When true, the ACL defines restrictions. Listed actions are forbidden. When
13736 false, listed actions are allowed.
13741 @deftp {Data Type} zone-entry
13742 Data type represnting a record entry in a zone file.
13743 This type has the following parameters:
13746 @item @code{name} (default: @code{"@@"})
13747 The name of the record. @code{"@@"} refers to the origin of the zone. Names
13748 are relative to the origin of the zone. For example, in the @code{example.org}
13749 zone, @code{"ns.example.org"} actually refers to @code{ns.example.org.example.org}.
13750 Names ending with a dot are absolute, which means that @code{"ns.example.org."}
13751 refers to @code{ns.example.org}.
13753 @item @code{ttl} (default: @code{""})
13754 The Time-To-Live (TTL) of this record. If not set, the default TTL is used.
13756 @item @code{class} (default: @code{"IN"})
13757 The class of the record. Knot currently supports only @code{"IN"} and
13758 partially @code{"CH"}.
13760 @item @code{type} (default: @code{"A"})
13761 The type of the record. Common types include A (IPv4 address), AAAA (IPv6
13762 address), NS (Name Server) and MX (Mail eXchange). Many other types are
13765 @item @code{data} (default: @code{""})
13766 The data contained in the record. For instance an IP address associated with
13767 an A record, or a domain name associated with an NS record. Remember that
13768 domain names are relative to the origin unless they end with a dot.
13773 @deftp {Data Type} zone-file
13774 Data type representing the content of a zone file.
13775 This type has the following parameters:
13778 @item @code{entries} (default: @code{'()})
13779 The list of entries. The SOA record is taken care of, so you don't need to
13780 put it in the list of entries. This list should probably contain an entry
13781 for your primary authoritative DNS server. Other than using a list of entries
13782 directly, you can use @code{define-zone-entries} to define a object containing
13783 the list of entries more easily, that you can later pass to the @code{entries}
13784 field of the @code{zone-file}.
13786 @item @code{origin} (default: @code{""})
13787 The name of your zone. This parameter cannot be empty.
13789 @item @code{ns} (default: @code{"ns"})
13790 The domain of your primary authoritative DNS server. The name is relative to
13791 the origin, unless it ends with a dot. It is mandatory that this primary
13792 DNS server corresponds to an NS record in the zone and that it is associated
13793 to an IP address in the list of entries.
13795 @item @code{mail} (default: @code{"hostmaster"})
13796 An email address people can contact you at, as the owner of the zone. This
13797 is translated as @code{<mail>@@<origin>}.
13799 @item @code{serial} (default: @code{1})
13800 The serial number of the zone. As this is used to keep track of changes by
13801 both slaves and resolvers, it is mandatory that it @emph{never} decreases.
13802 Always increment it when you make a change in your zone.
13804 @item @code{refresh} (default: @code{"2d"})
13805 The frequency at which slaves will do a zone transfer. This value can be
13806 a number of seconds or a number of some unit between:
13814 @item @code{retry} (default: @code{"15m"})
13815 The period after which a slave will retry to contact its master when it fails
13816 to do so a first time.
13818 @item @code{expiry} (default: @code{"2w"})
13819 Default TTL of records. Existing records are considered correct for at most
13820 this amount of time. After this period, resolvers will invalidate their cache
13821 and check again that it still exists.
13823 @item @code{nx} (default: @code{"1h"})
13824 Default TTL of inexistant records. This delay is usually short because you want
13825 your new domains to reach everyone quickly.
13830 @deftp {Data Type} knot-remote-configuration
13831 Data type representing a remote configuration.
13832 This type has the following parameters:
13835 @item @code{id} (default: @code{""})
13836 An identifier for other configuration fields to refer to this remote. IDs must
13837 be unique and must not be empty.
13839 @item @code{address} (default: @code{'()})
13840 An ordered list of destination IP addresses. Addresses are tried in sequence.
13841 An optional port can be given with the @@ separator. For instance:
13842 @code{(list "1.2.3.4" "2.3.4.5@@53")}. Default port is 53.
13844 @item @code{via} (default: @code{'()})
13845 An ordered list of source IP addresses. An empty list will have Knot choose
13846 an appropriate source IP. An optional port can be given with the @@ separator.
13847 The default is to choose at random.
13849 @item @code{key} (default: @code{#f})
13850 A reference to a key, that is a string containing the identifier of a key
13851 defined in a @code{knot-key-configuration} field.
13856 @deftp {Data Type} knot-keystore-configuration
13857 Data type representing a keystore to hold dnssec keys.
13858 This type has the following parameters:
13861 @item @code{id} (default: @code{""})
13862 The id of the keystore. It must not be empty.
13864 @item @code{backend} (default: @code{'pem})
13865 The backend to store the keys in. Can be @code{'pem} or @code{'pkcs11}.
13867 @item @code{config} (default: @code{"/var/lib/knot/keys/keys"})
13868 The configuration string of the backend. An example for the PKCS#11 is:
13869 @code{"pkcs11:token=knot;pin-value=1234 /gnu/store/.../lib/pkcs11/libsofthsm2.so"}.
13870 For the pem backend, the string reprensents a path in the filesystem.
13875 @deftp {Data Type} knot-policy-configuration
13876 Data type representing a dnssec policy. Knot DNS is able to automatically
13877 sign your zones. It can either generate and manage your keys automatically or
13878 use keys that you generate.
13880 Dnssec is usually implemented using two keys: a Key Signing Key (KSK) that is
13881 used to sign the second, and a Zone Signing Key (ZSK) that is used to sign the
13882 zone. In order to be trusted, the KSK needs to be present in the parent zone
13883 (usually a top-level domain). If your registrar supports dnssec, you will
13884 have to send them your KSK's hash so they can add a DS record in their zone.
13885 This is not automated and need to be done each time you change your KSK.
13887 The policy also defines the lifetime of keys. Usually, ZSK can be changed
13888 easily and use weaker cryptographic functions (they use lower parameters) in
13889 order to sign records quickly, so they are changed often. The KSK however
13890 requires manual interaction with the registrar, so they are changed less often
13891 and use stronger parameters because they sign only one record.
13893 This type has the following parameters:
13896 @item @code{id} (default: @code{""})
13897 The id of the policy. It must not be empty.
13899 @item @code{keystore} (default: @code{"default"})
13900 A reference to a keystore, that is a string containing the identifier of a
13901 keystore defined in a @code{knot-keystore-configuration} field. The
13902 @code{"default"} identifier means the default keystore (a kasp database that
13903 was setup by this service).
13905 @item @code{manual?} (default: @code{#f})
13906 Whether the key management is manual or automatic.
13908 @item @code{single-type-signing?} (default: @code{#f})
13909 When @code{#t}, use the Single-Type Signing Scheme.
13911 @item @code{algorithm} (default: @code{"ecdsap256sha256"})
13912 An algorithm of signing keys and issued signatures.
13914 @item @code{ksk-size} (default: @code{256})
13915 The length of the KSK. Note that this value is correct for the default
13916 algorithm, but would be unsecure for other algorithms.
13918 @item @code{zsk-size} (default: @code{256})
13919 The length of the ZSK. Note that this value is correct for the default
13920 algorithm, but would be unsecure for other algorithms.
13922 @item @code{dnskey-ttl} (default: @code{'default})
13923 The TTL value for DNSKEY records added into zone apex. The special
13924 @code{'default} value means same as the zone SOA TTL.
13926 @item @code{zsk-lifetime} (default: @code{"30d"})
13927 The period between ZSK publication and the next rollover initiation.
13929 @item @code{propagation-delay} (default: @code{"1d"})
13930 An extra delay added for each key rollover step. This value should be high
13931 enough to cover propagation of data from the master server to all slaves.
13933 @item @code{rrsig-lifetime} (default: @code{"14d"})
13934 A validity period of newly issued signatures.
13936 @item @code{rrsig-refresh} (default: @code{"7d"})
13937 A period how long before a signature expiration the signature will be refreshed.
13939 @item @code{nsec3?} (default: @code{#f})
13940 When @code{#t}, NSEC3 will be used instead of NSEC.
13942 @item @code{nsec3-iterations} (default: @code{5})
13943 The number of additional times the hashing is performed.
13945 @item @code{nsec3-salt-length} (default: @code{8})
13946 The length of a salt field in octets, which is appended to the original owner
13947 name before hashing.
13949 @item @code{nsec3-salt-lifetime} (default: @code{"30d"})
13950 The validity period of newly issued salt field.
13955 @deftp {Data Type} knot-zone-configuration
13956 Data type representing a zone served by Knot.
13957 This type has the following parameters:
13960 @item @code{domain} (default: @code{""})
13961 The domain served by this configuration. It must not be empty.
13963 @item @code{file} (default: @code{""})
13964 The file where this zone is saved. This parameter is ignored by master zones.
13965 Empty means default location that depends on the domain name.
13967 @item @code{zone} (default: @code{(zone-file)})
13968 The content of the zone file. This parameter is ignored by slave zones. It
13969 must contain a zone-file record.
13971 @item @code{master} (default: @code{'()})
13972 A list of master remotes. When empty, this zone is a master. When set, this
13973 zone is a slave. This is a list of remotes identifiers.
13975 @item @code{ddns-master} (default: @code{#f})
13976 The main master. When empty, it defaults to the first master in the list of
13979 @item @code{notify} (default: @code{'()})
13980 A list of slave remote identifiers.
13982 @item @code{acl} (default: @code{'()})
13983 A list of acl identifiers.
13985 @item @code{semantic-checks?} (default: @code{#f})
13986 When set, this adds more semantic checks to the zone.
13988 @item @code{disable-any?} (default: @code{#f})
13989 When set, this forbids queries of the ANY type.
13991 @item @code{zonefile-sync} (default: @code{0})
13992 The delay between a modification in memory and on disk. 0 means immediate
13995 @item @code{serial-policy} (default: @code{'increment})
13996 A policy between @code{'increment} and @code{'unixtime}.
14001 @deftp {Data Type} knot-configuration
14002 Data type representing the Knot configuration.
14003 This type has the following parameters:
14006 @item @code{knot} (default: @code{knot})
14009 @item @code{run-directory} (default: @code{"/var/run/knot"})
14010 The run directory. This directory will be used for pid file and sockets.
14012 @item @code{listen-v4} (default: @code{"0.0.0.0"})
14013 An ip address on which to listen.
14015 @item @code{listen-v6} (default: @code{"::"})
14016 An ip address on which to listen.
14018 @item @code{listen-port} (default: @code{53})
14019 A port on which to listen.
14021 @item @code{keys} (default: @code{'()})
14022 The list of knot-key-configuration used by this configuration.
14024 @item @code{acls} (default: @code{'()})
14025 The list of knot-acl-configuration used by this configuration.
14027 @item @code{remotes} (default: @code{'()})
14028 The list of knot-remote-configuration used by this configuration.
14030 @item @code{zones} (default: @code{'()})
14031 The list of knot-zone-configuration used by this configuration.
14037 @subsubsection VPN Services
14038 @cindex VPN (virtual private network)
14039 @cindex virtual private network (VPN)
14041 The @code{(gnu services vpn)} module provides services related to
14042 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
14043 your machine to connect to a VPN, and a @emph{servire} service for your machine
14044 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
14046 @deffn {Scheme Procedure} openvpn-client-service @
14047 [#:config (openvpn-client-configuration)]
14049 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
14052 @deffn {Scheme Procedure} openvpn-server-service @
14053 [#:config (openvpn-server-configuration)]
14055 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
14057 Both can be run simultaneously.
14060 @c %automatically generated documentation
14062 Available @code{openvpn-client-configuration} fields are:
14064 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
14065 The OpenVPN package.
14069 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
14070 The OpenVPN pid file.
14072 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14076 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
14077 The protocol (UDP or TCP) used to open a channel between clients and
14080 Defaults to @samp{udp}.
14084 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
14085 The device type used to represent the VPN connection.
14087 Defaults to @samp{tun}.
14091 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
14092 The certificate authority to check connections against.
14094 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14098 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
14099 The certificate of the machine the daemon is running on. It should be
14100 signed by the authority given in @code{ca}.
14102 Defaults to @samp{"/etc/openvpn/client.crt"}.
14106 @deftypevr {@code{openvpn-client-configuration} parameter} string key
14107 The key of the machine the daemon is running on. It must be the key whose
14108 certificate is @code{cert}.
14110 Defaults to @samp{"/etc/openvpn/client.key"}.
14114 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
14115 Whether to use the lzo compression algorithm.
14117 Defaults to @samp{#t}.
14121 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
14122 Don't re-read key files across SIGUSR1 or --ping-restart.
14124 Defaults to @samp{#t}.
14128 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
14129 Don't close and reopen TUN/TAP device or run up/down scripts across
14130 SIGUSR1 or --ping-restart restarts.
14132 Defaults to @samp{#t}.
14136 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
14139 Defaults to @samp{3}.
14143 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
14144 Add an additional layer of HMAC authentication on top of the TLS control
14145 channel to protect against DoS attacks.
14147 Defaults to @samp{#f}.
14151 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
14152 Whether to check the server certificate has server usage extension.
14154 Defaults to @samp{#t}.
14158 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
14159 Bind to a specific local port number.
14161 Defaults to @samp{#f}.
14165 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
14166 Retry resolving server address.
14168 Defaults to @samp{#t}.
14172 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
14173 A list of remote servers to connect to.
14175 Defaults to @samp{()}.
14177 Available @code{openvpn-remote-configuration} fields are:
14179 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
14182 Defaults to @samp{"my-server"}.
14186 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
14187 Port number the server listens to.
14189 Defaults to @samp{1194}.
14194 @c %end of automatic openvpn-client documentation
14196 @c %automatically generated documentation
14198 Available @code{openvpn-server-configuration} fields are:
14200 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
14201 The OpenVPN package.
14205 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
14206 The OpenVPN pid file.
14208 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14212 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
14213 The protocol (UDP or TCP) used to open a channel between clients and
14216 Defaults to @samp{udp}.
14220 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
14221 The device type used to represent the VPN connection.
14223 Defaults to @samp{tun}.
14227 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
14228 The certificate authority to check connections against.
14230 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14234 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
14235 The certificate of the machine the daemon is running on. It should be
14236 signed by the authority given in @code{ca}.
14238 Defaults to @samp{"/etc/openvpn/client.crt"}.
14242 @deftypevr {@code{openvpn-server-configuration} parameter} string key
14243 The key of the machine the daemon is running on. It must be the key whose
14244 certificate is @code{cert}.
14246 Defaults to @samp{"/etc/openvpn/client.key"}.
14250 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
14251 Whether to use the lzo compression algorithm.
14253 Defaults to @samp{#t}.
14257 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
14258 Don't re-read key files across SIGUSR1 or --ping-restart.
14260 Defaults to @samp{#t}.
14264 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
14265 Don't close and reopen TUN/TAP device or run up/down scripts across
14266 SIGUSR1 or --ping-restart restarts.
14268 Defaults to @samp{#t}.
14272 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
14275 Defaults to @samp{3}.
14279 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
14280 Add an additional layer of HMAC authentication on top of the TLS control
14281 channel to protect against DoS attacks.
14283 Defaults to @samp{#f}.
14287 @deftypevr {@code{openvpn-server-configuration} parameter} number port
14288 Specifies the port number on which the server listens.
14290 Defaults to @samp{1194}.
14294 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
14295 An ip and mask specifying the subnet inside the virtual network.
14297 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
14301 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
14302 A CIDR notation specifying the IPv6 subnet inside the virtual network.
14304 Defaults to @samp{#f}.
14308 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
14309 The Diffie-Hellman parameters file.
14311 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
14315 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
14316 The file that records client IPs.
14318 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
14322 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
14323 When true, the server will act as a gateway for its clients.
14325 Defaults to @samp{#f}.
14329 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
14330 When true, clients are allowed to talk to each other inside the VPN.
14332 Defaults to @samp{#f}.
14336 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
14337 Causes ping-like messages to be sent back and forth over the link so
14338 that each side knows when the other side has gone down. @code{keepalive}
14339 requires a pair. The first element is the period of the ping sending,
14340 and the second element is the timeout before considering the other side
14345 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
14346 The maximum number of clients.
14348 Defaults to @samp{100}.
14352 @deftypevr {@code{openvpn-server-configuration} parameter} string status
14353 The status file. This file shows a small report on current connection.
14354 It is truncated and rewritten every minute.
14356 Defaults to @samp{"/var/run/openvpn/status"}.
14360 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
14361 The list of configuration for some clients.
14363 Defaults to @samp{()}.
14365 Available @code{openvpn-ccd-configuration} fields are:
14367 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
14370 Defaults to @samp{"client"}.
14374 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
14377 Defaults to @samp{#f}.
14381 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
14384 Defaults to @samp{#f}.
14391 @c %end of automatic openvpn-server documentation
14394 @node Network File System
14395 @subsubsection Network File System
14398 The @code{(gnu services nfs)} module provides the following services,
14399 which are most commonly used in relation to mounting or exporting
14400 directory trees as @dfn{network file systems} (NFS).
14402 @subsubheading RPC Bind Service
14405 The RPC Bind service provides a facility to map program numbers into
14406 universal addresses.
14407 Many NFS related services use this facility. Hence it is automatically
14408 started when a dependent service starts.
14410 @defvr {Scheme Variable} rpcbind-service-type
14411 A service type for the RPC portmapper daemon.
14415 @deftp {Data Type} rpcbind-configuration
14416 Data type representing the configuration of the RPC Bind Service.
14417 This type has the following parameters:
14419 @item @code{rpcbind} (default: @code{rpcbind})
14420 The rpcbind package to use.
14422 @item @code{warm-start?} (default: @code{#t})
14423 If this parameter is @code{#t}, then the daemon will read a
14424 state file on startup thus reloading state information saved by a previous
14430 @subsubheading Pipefs Pseudo File System
14434 The pipefs file system is used to transfer NFS related data
14435 between the kernel and user space programs.
14437 @defvr {Scheme Variable} pipefs-service-type
14438 A service type for the pipefs pseudo file system.
14441 @deftp {Data Type} pipefs-configuration
14442 Data type representing the configuration of the pipefs pseudo file system service.
14443 This type has the following parameters:
14445 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14446 The directory to which the file system is to be attached.
14451 @subsubheading GSS Daemon Service
14454 @cindex global security system
14456 The @dfn{global security system} (GSS) daemon provides strong security for RPC
14458 Before exchanging RPC requests an RPC client must establish a security
14459 context. Typically this is done using the Kerberos command @command{kinit}
14460 or automatically at login time using PAM services (@pxref{Kerberos Services}).
14462 @defvr {Scheme Variable} gss-service-type
14463 A service type for the Global Security System (GSS) daemon.
14466 @deftp {Data Type} gss-configuration
14467 Data type representing the configuration of the GSS daemon service.
14468 This type has the following parameters:
14470 @item @code{nfs-utils} (default: @code{nfs-utils})
14471 The package in which the @command{rpc.gssd} command is to be found.
14473 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14474 The directory where the pipefs file system is mounted.
14480 @subsubheading IDMAP Daemon Service
14482 @cindex name mapper
14484 The idmap daemon service provides mapping between user IDs and user names.
14485 Typically it is required in order to access file systems mounted via NFSv4.
14487 @defvr {Scheme Variable} idmap-service-type
14488 A service type for the Identity Mapper (IDMAP) daemon.
14491 @deftp {Data Type} idmap-configuration
14492 Data type representing the configuration of the IDMAP daemon service.
14493 This type has the following parameters:
14495 @item @code{nfs-utils} (default: @code{nfs-utils})
14496 The package in which the @command{rpc.idmapd} command is to be found.
14498 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14499 The directory where the pipefs file system is mounted.
14501 @item @code{domain} (default: @code{#f})
14502 The local NFSv4 domain name.
14503 This must be a string or @code{#f}.
14504 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
14509 @node Continuous Integration
14510 @subsubsection Continuous Integration
14512 @cindex continuous integration
14513 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
14514 integration tool for Guix. It can be used both for development and for
14515 providing substitutes to others (@pxref{Substitutes}).
14517 The @code{(gnu services cuirass)} module provides the following service.
14519 @defvr {Scheme Procedure} cuirass-service-type
14520 The type of the Cuirass service. Its value must be a
14521 @code{cuirass-configuration} object, as described below.
14524 To add build jobs, you have to set the @code{specifications} field of
14525 the configuration. Here is an example of a service defining a build job
14526 based on a specification that can be found in Cuirass source tree. This
14527 service polls the Guix repository and builds a subset of the Guix
14528 packages, as prescribed in the @file{gnu-system.scm} example spec:
14531 (let ((spec #~((#:name . "guix")
14532 (#:url . "git://git.savannah.gnu.org/guix.git")
14533 (#:load-path . ".")
14535 ;; Here we must provide an absolute file name.
14536 ;; We take jobs from one of the examples provided
14538 (#:file . #$(file-append
14540 "/tests/gnu-system.scm"))
14542 (#:proc . hydra-jobs)
14543 (#:arguments (subset . "hello"))
14544 (#:branch . "master"))))
14545 (service cuirass-service-type
14546 (cuirass-configuration
14547 (specifications #~(list #$spec)))))
14550 While information related to build jobs is located directly in the
14551 specifications, global settings for the @command{cuirass} process are
14552 accessible in other @code{cuirass-configuration} fields.
14554 @deftp {Data Type} cuirass-configuration
14555 Data type representing the configuration of Cuirass.
14558 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
14559 Location of the log file.
14561 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
14562 Location of the repository cache.
14564 @item @code{user} (default: @code{"cuirass"})
14565 Owner of the @code{cuirass} process.
14567 @item @code{group} (default: @code{"cuirass"})
14568 Owner's group of the @code{cuirass} process.
14570 @item @code{interval} (default: @code{60})
14571 Number of seconds between the poll of the repositories followed by the
14574 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
14575 Location of sqlite database which contains the build results and previously
14576 added specifications.
14578 @item @code{port} (default: @code{8080})
14579 Port number used by the HTTP server.
14581 @item @code{specifications} (default: @code{#~'()})
14582 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
14583 where a specification is an association list
14584 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
14585 keys are keywords (@code{#:keyword-example}) as shown in the example
14588 @item @code{use-substitutes?} (default: @code{#f})
14589 This allows using substitutes to avoid building every dependencies of a job
14592 @item @code{one-shot?} (default: @code{#f})
14593 Only evaluate specifications and build derivations once.
14595 @item @code{load-path} (default: @code{'()})
14596 This allows users to define their own packages and make them visible to
14597 cuirass as in @command{guix build} command.
14599 @item @code{cuirass} (default: @code{cuirass})
14600 The Cuirass package to use.
14604 @node Power management Services
14605 @subsubsection Power management Services
14607 @cindex power management with TLP
14608 The @code{(gnu services pm)} module provides a Guix service definition
14609 for the Linux power management tool TLP.
14611 TLP enables various powersaving modes in userspace and kernel.
14612 Contrary to @code{upower-service}, it is not a passive,
14613 monitoring tool, as it will apply custom settings each time a new power
14614 source is detected. More information can be found at
14615 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
14617 @deffn {Scheme Variable} tlp-service-type
14618 The service type for the TLP tool. Its value should be a valid
14619 TLP configuration (see below). To use the default settings, simply
14622 (service tlp-service-type)
14626 By default TLP does not need much configuration but most TLP parameters
14627 can be tweaked using @code{tlp-configuration}.
14629 Each parameter definition is preceded by its type; for example,
14630 @samp{boolean foo} indicates that the @code{foo} parameter
14631 should be specified as a boolean. Types starting with
14632 @code{maybe-} denote parameters that won't show up in TLP config file
14633 when their value is @code{'disabled}.
14635 @c The following documentation was initially generated by
14636 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
14637 @c documentation is better, so we shouldn't hesitate to edit below as
14638 @c needed. However if the change you want to make to this documentation
14639 @c can be done in an automated way, it's probably easier to change
14640 @c (generate-documentation) than to make it below and have to deal with
14641 @c the churn as TLP updates.
14643 Available @code{tlp-configuration} fields are:
14645 @deftypevr {@code{tlp-configuration} parameter} package tlp
14650 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
14651 Set to true if you wish to enable TLP.
14653 Defaults to @samp{#t}.
14657 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
14658 Default mode when no power supply can be detected. Alternatives are AC
14661 Defaults to @samp{"AC"}.
14665 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
14666 Number of seconds Linux kernel has to wait after the disk goes idle,
14667 before syncing on AC.
14669 Defaults to @samp{0}.
14673 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
14674 Same as @code{disk-idle-ac} but on BAT mode.
14676 Defaults to @samp{2}.
14680 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
14681 Dirty pages flushing periodicity, expressed in seconds.
14683 Defaults to @samp{15}.
14687 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
14688 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
14690 Defaults to @samp{60}.
14694 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
14695 CPU frequency scaling governor on AC mode. With intel_pstate driver,
14696 alternatives are powersave and performance. With acpi-cpufreq driver,
14697 alternatives are ondemand, powersave, performance and conservative.
14699 Defaults to @samp{disabled}.
14703 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
14704 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
14706 Defaults to @samp{disabled}.
14710 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
14711 Set the min available frequency for the scaling governor on AC.
14713 Defaults to @samp{disabled}.
14717 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
14718 Set the max available frequency for the scaling governor on AC.
14720 Defaults to @samp{disabled}.
14724 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
14725 Set the min available frequency for the scaling governor on BAT.
14727 Defaults to @samp{disabled}.
14731 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
14732 Set the max available frequency for the scaling governor on BAT.
14734 Defaults to @samp{disabled}.
14738 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
14739 Limit the min P-state to control the power dissipation of the CPU, in AC
14740 mode. Values are stated as a percentage of the available performance.
14742 Defaults to @samp{disabled}.
14746 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
14747 Limit the max P-state to control the power dissipation of the CPU, in AC
14748 mode. Values are stated as a percentage of the available performance.
14750 Defaults to @samp{disabled}.
14754 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
14755 Same as @code{cpu-min-perf-on-ac} on BAT mode.
14757 Defaults to @samp{disabled}.
14761 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
14762 Same as @code{cpu-max-perf-on-ac} on BAT mode.
14764 Defaults to @samp{disabled}.
14768 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
14769 Enable CPU turbo boost feature on AC mode.
14771 Defaults to @samp{disabled}.
14775 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
14776 Same as @code{cpu-boost-on-ac?} on BAT mode.
14778 Defaults to @samp{disabled}.
14782 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
14783 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
14784 used under light load conditions.
14786 Defaults to @samp{#f}.
14790 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
14791 Same as @code{sched-powersave-on-ac?} but on BAT mode.
14793 Defaults to @samp{#t}.
14797 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
14798 Enable Linux kernel NMI watchdog.
14800 Defaults to @samp{#f}.
14804 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
14805 For Linux kernels with PHC patch applied, change CPU voltages. An
14806 example value would be @samp{"F:V F:V F:V F:V"}.
14808 Defaults to @samp{disabled}.
14812 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
14813 Set CPU performance versus energy saving policy on AC. Alternatives are
14814 performance, normal, powersave.
14816 Defaults to @samp{"performance"}.
14820 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
14821 Same as @code{energy-perf-policy-ac} but on BAT mode.
14823 Defaults to @samp{"powersave"}.
14827 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
14832 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
14833 Hard disk advanced power management level.
14837 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
14838 Same as @code{disk-apm-bat} but on BAT mode.
14842 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
14843 Hard disk spin down timeout. One value has to be specified for each
14844 declared hard disk.
14846 Defaults to @samp{disabled}.
14850 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
14851 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
14853 Defaults to @samp{disabled}.
14857 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
14858 Select IO scheduler for disk devices. One value has to be specified for
14859 each declared hard disk. Example alternatives are cfq, deadline and
14862 Defaults to @samp{disabled}.
14866 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
14867 SATA aggressive link power management (ALPM) level. Alternatives are
14868 min_power, medium_power, max_performance.
14870 Defaults to @samp{"max_performance"}.
14874 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
14875 Same as @code{sata-linkpwr-ac} but on BAT mode.
14877 Defaults to @samp{"min_power"}.
14881 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
14882 Exclude specified SATA host devices for link power management.
14884 Defaults to @samp{disabled}.
14888 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
14889 Enable Runtime Power Management for AHCI controller and disks on AC
14892 Defaults to @samp{disabled}.
14896 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
14897 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
14899 Defaults to @samp{disabled}.
14903 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
14904 Seconds of inactivity before disk is suspended.
14906 Defaults to @samp{15}.
14910 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
14911 PCI Express Active State Power Management level. Alternatives are
14912 default, performance, powersave.
14914 Defaults to @samp{"performance"}.
14918 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
14919 Same as @code{pcie-aspm-ac} but on BAT mode.
14921 Defaults to @samp{"powersave"}.
14925 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
14926 Radeon graphics clock speed level. Alternatives are low, mid, high,
14929 Defaults to @samp{"high"}.
14933 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
14934 Same as @code{radeon-power-ac} but on BAT mode.
14936 Defaults to @samp{"low"}.
14940 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
14941 Radeon dynamic power management method (DPM). Alternatives are battery,
14944 Defaults to @samp{"performance"}.
14948 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
14949 Same as @code{radeon-dpm-state-ac} but on BAT mode.
14951 Defaults to @samp{"battery"}.
14955 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
14956 Radeon DPM performance level. Alternatives are auto, low, high.
14958 Defaults to @samp{"auto"}.
14962 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
14963 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
14965 Defaults to @samp{"auto"}.
14969 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
14970 Wifi power saving mode.
14972 Defaults to @samp{#f}.
14976 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
14977 Same as @code{wifi-power-ac?} but on BAT mode.
14979 Defaults to @samp{#t}.
14983 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
14984 Disable wake on LAN.
14986 Defaults to @samp{#t}.
14990 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
14991 Timeout duration in seconds before activating audio power saving on
14992 Intel HDA and AC97 devices. A value of 0 disables power saving.
14994 Defaults to @samp{0}.
14998 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
14999 Same as @code{sound-powersave-ac} but on BAT mode.
15001 Defaults to @samp{1}.
15005 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
15006 Disable controller in powersaving mode on Intel HDA devices.
15008 Defaults to @samp{#t}.
15012 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
15013 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
15014 powered on again by releasing (and reinserting) the eject lever or by
15015 pressing the disc eject button on newer models.
15017 Defaults to @samp{#f}.
15021 @deftypevr {@code{tlp-configuration} parameter} string bay-device
15022 Name of the optical drive device to power off.
15024 Defaults to @samp{"sr0"}.
15028 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
15029 Runtime Power Management for PCI(e) bus devices. Alternatives are on
15032 Defaults to @samp{"on"}.
15036 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
15037 Same as @code{runtime-pm-ac} but on BAT mode.
15039 Defaults to @samp{"auto"}.
15043 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
15044 Runtime Power Management for all PCI(e) bus devices, except blacklisted
15047 Defaults to @samp{#t}.
15051 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
15052 Exclude specified PCI(e) device addresses from Runtime Power Management.
15054 Defaults to @samp{disabled}.
15058 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
15059 Exclude PCI(e) devices assigned to the specified drivers from Runtime
15064 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
15065 Enable USB autosuspend feature.
15067 Defaults to @samp{#t}.
15071 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
15072 Exclude specified devices from USB autosuspend.
15074 Defaults to @samp{disabled}.
15078 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
15079 Exclude WWAN devices from USB autosuspend.
15081 Defaults to @samp{#t}.
15085 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
15086 Include specified devices into USB autosuspend, even if they are already
15087 excluded by the driver or via @code{usb-blacklist-wwan?}.
15089 Defaults to @samp{disabled}.
15093 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
15094 Enable USB autosuspend before shutdown.
15096 Defaults to @samp{disabled}.
15100 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
15101 Restore radio device state (bluetooth, wifi, wwan) from previous
15102 shutdown on system startup.
15104 Defaults to @samp{#f}.
15109 The @code{(gnu services pm)} module provides an interface to
15110 thermald, a CPU frequency scaling service which helps prevent overheating.
15112 @defvr {Scheme Variable} thermald-service-type
15113 This is the service type for
15114 @uref{https://01.org/linux-thermal-daemon/, thermald}, the Linux
15115 Thermal Daemon, which is responsible for controlling the thermal state
15116 of processors and preventing overheating.
15119 @deftp {Data Type} thermald-configuration
15120 Data type representing the configuration of @code{thermald-service-type}.
15123 @item @code{ignore-cpuid-check?} (default: @code{#f})
15124 Ignore cpuid check for supported CPU models.
15126 @item @code{thermald} (default: @var{thermald})
15127 Package object of thermald.
15133 @node Miscellaneous Services
15134 @subsubsection Miscellaneous Services
15138 @subsubheading Lirc Service
15140 The @code{(gnu services lirc)} module provides the following service.
15142 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
15143 [#:device #f] [#:driver #f] [#:config-file #f] @
15144 [#:extra-options '()]
15145 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
15146 decodes infrared signals from remote controls.
15148 Optionally, @var{device}, @var{driver} and @var{config-file}
15149 (configuration file name) may be specified. See @command{lircd} manual
15152 Finally, @var{extra-options} is a list of additional command-line options
15153 passed to @command{lircd}.
15157 @subsubheading Spice Service
15159 The @code{(gnu services spice)} module provides the following service.
15161 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
15162 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
15163 that enables sharing the clipboard with a vm and setting the guest display
15164 resolution when the graphical console window resizes.
15167 @subsubsection Dictionary Services
15169 The @code{(gnu services dict)} module provides the following service:
15171 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
15172 Return a service that runs the @command{dicod} daemon, an implementation
15173 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
15175 The optional @var{config} argument specifies the configuration for
15176 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
15177 default it serves the GNU Collaborative International Dictonary of English.
15179 You can add @command{open localhost} to your @file{~/.dico} file to make
15180 @code{localhost} the default server for @command{dico} client
15181 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
15184 @deftp {Data Type} dicod-configuration
15185 Data type representing the configuration of dicod.
15188 @item @code{dico} (default: @var{dico})
15189 Package object of the GNU Dico dictionary server.
15191 @item @code{interfaces} (default: @var{'("localhost")})
15192 This is the list of IP addresses and ports and possibly socket file
15193 names to listen to (@pxref{Server Settings, @code{listen} directive,,
15194 dico, GNU Dico Manual}).
15196 @item @code{handlers} (default: @var{'()})
15197 List of @code{<dicod-handler>} objects denoting handlers (module instances).
15199 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
15200 List of @code{<dicod-database>} objects denoting dictionaries to be served.
15204 @deftp {Data Type} dicod-handler
15205 Data type representing a dictionary handler (module instance).
15209 Name of the handler (module instance).
15211 @item @code{module} (default: @var{#f})
15212 Name of the dicod module of the handler (instance). If it is @code{#f},
15213 the module has the same name as the handler.
15214 (@pxref{Modules,,, dico, GNU Dico Manual}).
15216 @item @code{options}
15217 List of strings or gexps representing the arguments for the module handler
15221 @deftp {Data Type} dicod-database
15222 Data type representing a dictionary database.
15226 Name of the database, will be used in DICT commands.
15228 @item @code{handler}
15229 Name of the dicod handler (module instance) used by this database
15230 (@pxref{Handlers,,, dico, GNU Dico Manual}).
15232 @item @code{complex?} (default: @var{#f})
15233 Whether the database configuration complex. The complex configuration
15234 will need a corresponding @code{<dicod-handler>} object, otherwise not.
15236 @item @code{options}
15237 List of strings or gexps representing the arguments for the database
15238 (@pxref{Databases,,, dico, GNU Dico Manual}).
15242 @defvr {Scheme Variable} %dicod-database:gcide
15243 A @code{<dicod-database>} object serving the GNU Collaborative International
15244 Dictionary of English using the @code{gcide} package.
15247 The following is an example @code{dicod-service} configuration.
15250 (dicod-service #:config
15251 (dicod-configuration
15252 (handlers (list (dicod-handler
15256 (list #~(string-append "dbdir=" #$wordnet))))))
15257 (databases (list (dicod-database
15260 (handler "wordnet")
15261 (options '("database=wn")))
15262 %dicod-database:gcide))))
15265 @subsubsection Version Control
15267 The @code{(gnu services version-control)} module provides the following services:
15269 @subsubheading Git daemon service
15271 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
15273 Return a service that runs @command{git daemon}, a simple TCP server to
15274 expose repositories over the Git protocol for anonymous access.
15276 The optional @var{config} argument should be a
15277 @code{<git-daemon-configuration>} object, by default it allows read-only
15278 access to exported@footnote{By creating the magic file
15279 "git-daemon-export-ok" in the repository directory.} repositories under
15284 @deftp {Data Type} git-daemon-configuration
15285 Data type representing the configuration for @code{git-daemon-service}.
15288 @item @code{package} (default: @var{git})
15289 Package object of the Git distributed version control system.
15291 @item @code{export-all?} (default: @var{#f})
15292 Whether to allow access for all Git repositories, even if they do not
15293 have the @file{git-daemon-export-ok} file.
15295 @item @code{base-path} (default: @file{/srv/git})
15296 Whether to remap all the path requests as relative to the given path.
15297 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
15298 then if you later try to pull @code{git://example.com/hello.git}, git
15299 daemon will interpret the path as @code{/srv/git/hello.git}.
15301 @item @code{user-path} (default: @var{#f})
15302 Whether to allow @code{~user} notation to be used in requests. When
15303 specified with empty string, requests to @code{git://host/~alice/foo} is
15304 taken as a request to access @code{foo} repository in the home directory
15305 of user @code{alice}. If @var{(user-path "path")} is specified, the
15306 same request is taken as a request to access @code{path/foo} repository
15307 in the home directory of user @code{alice}.
15309 @item @code{listen} (default: @var{'()})
15310 Whether to listen on specific IP addresses or hostnames, defaults to
15313 @item @code{port} (default: @var{#f})
15314 Whether to listen on an alternative port, which defaults to 9418.
15316 @item @code{whitelist} (default: @var{'()})
15317 If not empty, only allow access to this list of directories.
15319 @item @code{extra-options} (default: @var{'()})
15320 Extra options will be passed to @code{git daemon}, please run
15321 @command{man git-daemon} for more information.
15326 @node Setuid Programs
15327 @subsection Setuid Programs
15329 @cindex setuid programs
15330 Some programs need to run with ``root'' privileges, even when they are
15331 launched by unprivileged users. A notorious example is the
15332 @command{passwd} program, which users can run to change their
15333 password, and which needs to access the @file{/etc/passwd} and
15334 @file{/etc/shadow} files---something normally restricted to root, for
15335 obvious security reasons. To address that, these executables are
15336 @dfn{setuid-root}, meaning that they always run with root privileges
15337 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
15338 for more info about the setuid mechanism.)
15340 The store itself @emph{cannot} contain setuid programs: that would be a
15341 security issue since any user on the system can write derivations that
15342 populate the store (@pxref{The Store}). Thus, a different mechanism is
15343 used: instead of changing the setuid bit directly on files that are in
15344 the store, we let the system administrator @emph{declare} which programs
15345 should be setuid root.
15347 The @code{setuid-programs} field of an @code{operating-system}
15348 declaration contains a list of G-expressions denoting the names of
15349 programs to be setuid-root (@pxref{Using the Configuration System}).
15350 For instance, the @command{passwd} program, which is part of the Shadow
15351 package, can be designated by this G-expression (@pxref{G-Expressions}):
15354 #~(string-append #$shadow "/bin/passwd")
15357 A default set of setuid programs is defined by the
15358 @code{%setuid-programs} variable of the @code{(gnu system)} module.
15360 @defvr {Scheme Variable} %setuid-programs
15361 A list of G-expressions denoting common programs that are setuid-root.
15363 The list includes commands such as @command{passwd}, @command{ping},
15364 @command{su}, and @command{sudo}.
15367 Under the hood, the actual setuid programs are created in the
15368 @file{/run/setuid-programs} directory at system activation time. The
15369 files in this directory refer to the ``real'' binaries, which are in the
15372 @node X.509 Certificates
15373 @subsection X.509 Certificates
15375 @cindex HTTPS, certificates
15376 @cindex X.509 certificates
15378 Web servers available over HTTPS (that is, HTTP over the transport-layer
15379 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
15380 that the client can then use to @emph{authenticate} the server. To do
15381 that, clients verify that the server's certificate is signed by a
15382 so-called @dfn{certificate authority} (CA). But to verify the CA's
15383 signature, clients must have first acquired the CA's certificate.
15385 Web browsers such as GNU@tie{}IceCat include their own set of CA
15386 certificates, such that they are able to verify CA signatures
15389 However, most other programs that can talk HTTPS---@command{wget},
15390 @command{git}, @command{w3m}, etc.---need to be told where CA
15391 certificates can be found.
15393 @cindex @code{nss-certs}
15394 In GuixSD, this is done by adding a package that provides certificates
15395 to the @code{packages} field of the @code{operating-system} declaration
15396 (@pxref{operating-system Reference}). GuixSD includes one such package,
15397 @code{nss-certs}, which is a set of CA certificates provided as part of
15398 Mozilla's Network Security Services.
15400 Note that it is @emph{not} part of @var{%base-packages}, so you need to
15401 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
15402 most applications and libraries look for certificates by default, points
15403 to the certificates installed globally.
15405 Unprivileged users, including users of Guix on a foreign distro,
15406 can also install their own certificate package in
15407 their profile. A number of environment variables need to be defined so
15408 that applications and libraries know where to find them. Namely, the
15409 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
15410 variables. Some applications add their own environment variables; for
15411 instance, the Git version control system honors the certificate bundle
15412 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
15413 would typically run something like:
15416 $ guix package -i nss-certs
15417 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
15418 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
15419 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
15422 As another example, R requires the @code{CURL_CA_BUNDLE} environment
15423 variable to point to a certificate bundle, so you would have to run
15424 something like this:
15427 $ guix package -i nss-certs
15428 $ export CURL_CA_BUNDLE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
15431 For other applications you may want to look up the required environment
15432 variable in the relevant documentation.
15435 @node Name Service Switch
15436 @subsection Name Service Switch
15438 @cindex name service switch
15440 The @code{(gnu system nss)} module provides bindings to the
15441 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
15442 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
15443 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
15444 extended with new ``name'' lookup methods for system databases, which
15445 includes host names, service names, user accounts, and more (@pxref{Name
15446 Service Switch, System Databases and Name Service Switch,, libc, The GNU
15447 C Library Reference Manual}).
15449 The NSS configuration specifies, for each system database, which lookup
15450 method is to be used, and how the various methods are chained
15451 together---for instance, under which circumstances NSS should try the
15452 next method in the list. The NSS configuration is given in the
15453 @code{name-service-switch} field of @code{operating-system} declarations
15454 (@pxref{operating-system Reference, @code{name-service-switch}}).
15457 @cindex .local, host name lookup
15458 As an example, the declaration below configures the NSS to use the
15459 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
15460 back-end}, which supports host name lookups over multicast DNS (mDNS)
15461 for host names ending in @code{.local}:
15464 (name-service-switch
15465 (hosts (list %files ;first, check /etc/hosts
15467 ;; If the above did not succeed, try
15468 ;; with 'mdns_minimal'.
15470 (name "mdns_minimal")
15472 ;; 'mdns_minimal' is authoritative for
15473 ;; '.local'. When it returns "not found",
15474 ;; no need to try the next methods.
15475 (reaction (lookup-specification
15476 (not-found => return))))
15478 ;; Then fall back to DNS.
15482 ;; Finally, try with the "full" 'mdns'.
15487 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
15488 contains this configuration, so you will not have to type it if all you
15489 want is to have @code{.local} host lookup working.
15491 Note that, in this case, in addition to setting the
15492 @code{name-service-switch} of the @code{operating-system} declaration,
15493 you also need to use @code{avahi-service} (@pxref{Networking Services,
15494 @code{avahi-service}}), or @var{%desktop-services}, which includes it
15495 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
15496 to the name service cache daemon (@pxref{Base Services,
15497 @code{nscd-service}}).
15499 For convenience, the following variables provide typical NSS
15502 @defvr {Scheme Variable} %default-nss
15503 This is the default name service switch configuration, a
15504 @code{name-service-switch} object.
15507 @defvr {Scheme Variable} %mdns-host-lookup-nss
15508 This is the name service switch configuration with support for host name
15509 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
15512 The reference for name service switch configuration is given below. It
15513 is a direct mapping of the configuration file format of the C library , so
15514 please refer to the C library manual for more information (@pxref{NSS
15515 Configuration File,,, libc, The GNU C Library Reference Manual}).
15516 Compared to the configuration file format of libc NSS, it has the advantage
15517 not only of adding this warm parenthetic feel that we like, but also
15518 static checks: you will know about syntax errors and typos as soon as you
15519 run @command{guix system}.
15521 @deftp {Data Type} name-service-switch
15523 This is the data type representation the configuration of libc's name
15524 service switch (NSS). Each field below represents one of the supported
15541 The system databases handled by the NSS. Each of these fields must be a
15542 list of @code{<name-service>} objects (see below).
15546 @deftp {Data Type} name-service
15548 This is the data type representing an actual name service and the
15549 associated lookup action.
15553 A string denoting the name service (@pxref{Services in the NSS
15554 configuration,,, libc, The GNU C Library Reference Manual}).
15556 Note that name services listed here must be visible to nscd. This is
15557 achieved by passing the @code{#:name-services} argument to
15558 @code{nscd-service} the list of packages providing the needed name
15559 services (@pxref{Base Services, @code{nscd-service}}).
15562 An action specified using the @code{lookup-specification} macro
15563 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
15564 Reference Manual}). For example:
15567 (lookup-specification (unavailable => continue)
15568 (success => return))
15573 @node Initial RAM Disk
15574 @subsection Initial RAM Disk
15577 @cindex initial RAM disk
15578 For bootstrapping purposes, the Linux-Libre kernel is passed an
15579 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
15580 root file system as well as an initialization script. The latter is
15581 responsible for mounting the real root file system, and for loading any
15582 kernel modules that may be needed to achieve that.
15584 The @code{initrd} field of an @code{operating-system} declaration allows
15585 you to specify which initrd you would like to use. The @code{(gnu
15586 system linux-initrd)} module provides three ways to build an initrd: the
15587 high-level @code{base-initrd} procedure and the low-level
15588 @code{raw-initrd} and @code{expression->initrd} procedures.
15590 The @code{base-initrd} procedure is intended to cover most common uses.
15591 For example, if you want to add a bunch of kernel modules to be loaded
15592 at boot time, you can define the @code{initrd} field of the operating
15593 system declaration like this:
15596 (initrd (lambda (file-systems . rest)
15597 ;; Create a standard initrd that has modules "foo.ko"
15598 ;; and "bar.ko", as well as their dependencies, in
15599 ;; addition to the modules available by default.
15600 (apply base-initrd file-systems
15601 #:extra-modules '("foo" "bar")
15605 The @code{base-initrd} procedure also handles common use cases that
15606 involves using the system as a QEMU guest, or as a ``live'' system with
15607 volatile root file system.
15609 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
15610 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
15611 such as trying to guess which kernel modules and packages should be included
15612 to the initrd. An example use of @code{raw-initrd} is when a user has
15613 a custom Linux kernel configuration and default kernel modules included by
15614 @code{base-initrd} are not available.
15616 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
15617 honors several options passed on the Linux kernel command line
15618 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
15619 @code{-append} option of QEMU), notably:
15622 @item --load=@var{boot}
15623 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
15624 program, once it has mounted the root file system.
15626 GuixSD uses this option to yield control to a boot program that runs the
15627 service activation programs and then spawns the GNU@tie{}Shepherd, the
15628 initialization system.
15630 @item --root=@var{root}
15631 Mount @var{root} as the root file system. @var{root} can be a
15632 device name like @code{/dev/sda1}, a partition label, or a partition
15635 @item --system=@var{system}
15636 Have @file{/run/booted-system} and @file{/run/current-system} point to
15639 @item modprobe.blacklist=@var{modules}@dots{}
15640 @cindex module, black-listing
15641 @cindex black list, of kernel modules
15642 Instruct the initial RAM disk as well as the @command{modprobe} command
15643 (from the kmod package) to refuse to load @var{modules}. @var{modules}
15644 must be a comma-separated list of module names---e.g.,
15645 @code{usbkbd,9pnet}.
15648 Start a read-eval-print loop (REPL) from the initial RAM disk before it
15649 tries to load kernel modules and to mount the root file system. Our
15650 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
15651 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
15652 Manual}, for more information on Guile's REPL.
15656 Now that you know all the features that initial RAM disks produced by
15657 @code{base-initrd} and @code{raw-initrd} provide,
15658 here is how to use it and customize it further.
15661 @cindex initial RAM disk
15662 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
15663 [#:linux-modules '()] [#:mapped-devices '()] @
15664 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
15665 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
15666 a list of file systems to be mounted by the initrd, possibly in addition to
15667 the root file system specified on the kernel command line via @code{--root}.
15668 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
15669 @var{mapped-devices} is a list of device mappings to realize before
15670 @var{file-systems} are mounted (@pxref{Mapped Devices}).
15671 @var{helper-packages} is a list of packages to be copied in the initrd. It may
15672 include @code{e2fsck/static} or other packages needed by the initrd to check
15675 When @var{qemu-networking?} is true, set up networking with the standard QEMU
15676 parameters. When @var{virtio?} is true, load additional modules so that the
15677 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15679 When @var{volatile-root?} is true, the root file system is writable but any changes
15683 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
15684 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
15685 [#:virtio? #t] [#:extra-modules '()]
15686 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
15687 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
15688 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
15689 also behaves as in @code{raw-initrd}.
15691 When @var{virtio?} is true, load additional modules so that the
15692 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15694 The initrd is automatically populated with all the kernel modules necessary
15695 for @var{file-systems} and for the given options. However, additional kernel
15696 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
15697 loaded at boot time in the order in which they appear.
15700 Needless to say, the initrds we produce and use embed a
15701 statically-linked Guile, and the initialization program is a Guile
15702 program. That gives a lot of flexibility. The
15703 @code{expression->initrd} procedure builds such an initrd, given the
15704 program to run in that initrd.
15706 @deffn {Monadic Procedure} expression->initrd @var{exp} @
15707 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
15708 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
15709 containing @var{guile} and that evaluates @var{exp}, a G-expression,
15710 upon booting. All the derivations referenced by @var{exp} are
15711 automatically copied to the initrd.
15714 @node Bootloader Configuration
15715 @subsection Bootloader Configuration
15718 @cindex boot loader
15720 The operating system supports multiple bootloaders. The bootloader is
15721 configured using @code{bootloader-configuration} declaration. All the
15722 fields of this structure are bootloader agnostic except for one field,
15723 @code{bootloader} that indicates the bootloader to be configured and
15726 Some of the bootloaders do not honor every field of
15727 @code{bootloader-configuration}. For instance, the extlinux
15728 bootloader does not support themes and thus ignores the @code{theme}
15731 @deftp {Data Type} bootloader-configuration
15732 The type of a bootloader configuration declaration.
15736 @item @code{bootloader}
15737 @cindex EFI, bootloader
15738 @cindex UEFI, bootloader
15739 @cindex BIOS, bootloader
15740 The bootloader to use, as a @code{bootloader} object. For now
15741 @code{grub-bootloader}, @code{grub-efi-bootloader} and
15742 @code{extlinux-bootloader} are supported. @code{grub-efi-bootloader},
15743 allows to boot on modern systems using the @dfn{Unified Extensible
15744 Firmware Interface} (UEFI).
15746 Available bootloaders are described in @code{(gnu bootloader @dots{})}
15749 @item @code{device}
15750 This is a string denoting the boot device. It must be a device name
15751 understood by the bootloader @command{installer} command, such as
15752 @code{/dev/sda} or @code{(hd0)} (for GRUB, @pxref{Invoking grub-install,,, grub,
15755 @item @code{menu-entries} (default: @code{()})
15756 A possibly empty list of @code{menu-entry} objects (see below), denoting
15757 entries to appear in the bootloader menu, in addition to the current
15758 system entry and the entry pointing to previous system generations.
15761 @item @code{default-entry} (default: @code{0})
15762 The index of the default boot menu entry. Index 0 is for the entry of the
15765 @item @code{timeout} (default: @code{5})
15766 The number of seconds to wait for keyboard input before booting. Set to
15767 0 to boot immediately, and to -1 to wait indefinitely.
15769 @item @code{theme} (default: @var{#f})
15770 The bootloader theme object describing the theme to use. If no theme
15771 is provided, some bootloaders might use a default theme, that's true
15774 @item @code{terminal-outputs} (default: @code{'gfxterm})
15775 The output terminals used for the bootloader boot menu, as a list of
15776 symbols. GRUB accepts the values: @code{console}, @code{serial},
15777 @code{serial_@{0-3@}}, @code{gfxterm}, @code{vga_text},
15778 @code{mda_text}, @code{morse}, and @code{pkmodem}. This field
15779 corresponds to the GRUB variable GRUB_TERMINAL_OUTPUT (@pxref{Simple
15780 configuration,,, grub,GNU GRUB manual}).
15782 @item @code{terminal-inputs} (default: @code{'()})
15783 The input terminals used for the bootloader boot menu, as a list of
15784 symbols. For GRUB, the default is the native platform terminal as
15785 determined at run-time. GRUB accepts the values: @code{console},
15786 @code{serial}, @code{serial_@{0-3@}}, @code{at_keyboard}, and
15787 @code{usb_keyboard}. This field corresponds to the GRUB variable
15788 GRUB_TERMINAL_INPUT (@pxref{Simple configuration,,, grub,GNU GRUB
15791 @item @code{serial-unit} (default: @code{#f})
15792 The serial unit used by the bootloader, as an integer from 0 to 3.
15793 For GRUB it is choosen at run-time; currently GRUB chooses 0, which
15794 corresponds to COM1 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
15796 @item @code{serial-speed} (default: @code{#f})
15797 The speed of the serial interface, as an integer. For GRUB, the
15798 default value is chosen at run-time; currently GRUB chooses
15799 9600@tie{}bps (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
15806 Should you want to list additional boot menu entries @i{via} the
15807 @code{menu-entries} field above, you will need to create them with the
15808 @code{menu-entry} form. For example, imagine you want to be able to
15809 boot another distro (hard to imagine!), you can define a menu entry
15814 (label "The Other Distro")
15815 (linux "/boot/old/vmlinux-2.6.32")
15816 (linux-arguments '("root=/dev/sda2"))
15817 (initrd "/boot/old/initrd"))
15822 @deftp {Data Type} menu-entry
15823 The type of an entry in the bootloader menu.
15828 The label to show in the menu---e.g., @code{"GNU"}.
15831 The Linux kernel image to boot, for example:
15834 (file-append linux-libre "/bzImage")
15837 For GRUB, it is also possible to specify a device explicitly in the
15838 file path using GRUB's device naming convention (@pxref{Naming
15839 convention,,, grub, GNU GRUB manual}), for example:
15842 "(hd0,msdos1)/boot/vmlinuz"
15845 If the device is specified explicitly as above, then the @code{device}
15846 field is ignored entirely.
15848 @item @code{linux-arguments} (default: @code{()})
15849 The list of extra Linux kernel command-line arguments---e.g.,
15850 @code{("console=ttyS0")}.
15852 @item @code{initrd}
15853 A G-Expression or string denoting the file name of the initial RAM disk
15854 to use (@pxref{G-Expressions}).
15855 @item @code{device} (default: @code{#f})
15856 The device where the kernel and initrd are to be found---i.e., for GRUB,
15857 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
15859 This may be a file system label (a string), a file system UUID (a
15860 bytevector, @pxref{File Systems}), or @code{#f}, in which case
15861 the bootloader will search the device containing the file specified by
15862 the @code{linux} field (@pxref{search,,, grub, GNU GRUB manual}). It
15863 must @emph{not} be an OS device name such as @file{/dev/sda1}.
15868 @c FIXME: Write documentation once it's stable.
15869 Fow now only GRUB has theme support. GRUB themes are created using
15870 the @code{grub-theme} form, which is not documented yet.
15872 @defvr {Scheme Variable} %default-theme
15873 This is the default GRUB theme used by the operating system if no
15874 @code{theme} field is specified in @code{bootloader-configuration}
15877 It comes with a fancy background image displaying the GNU and Guix
15882 @node Invoking guix system
15883 @subsection Invoking @code{guix system}
15885 Once you have written an operating system declaration as seen in the
15886 previous section, it can be @dfn{instantiated} using the @command{guix
15887 system} command. The synopsis is:
15890 guix system @var{options}@dots{} @var{action} @var{file}
15893 @var{file} must be the name of a file containing an
15894 @code{operating-system} declaration. @var{action} specifies how the
15895 operating system is instantiated. Currently the following values are
15900 Build the operating system described in @var{file}, activate it, and
15901 switch to it@footnote{This action (and the related actions
15902 @code{switch-generation} and @code{roll-back}) are usable only on
15903 systems already running GuixSD.}.
15905 This effects all the configuration specified in @var{file}: user
15906 accounts, system services, global package list, setuid programs, etc.
15907 The command starts system services specified in @var{file} that are not
15908 currently running; if a service is currently running, it does not
15909 attempt to upgrade it since this would not be possible without stopping it
15912 This command creates a new generation whose number is one greater than
15913 the current generation (as reported by @command{guix system
15914 list-generations}). If that generation already exists, it will be
15915 overwritten. This behavior mirrors that of @command{guix package}
15916 (@pxref{Invoking guix package}).
15918 It also adds a bootloader menu entry for the new OS configuration,
15919 ---unless @option{--no-bootloader} is passed. For GRUB, it moves
15920 entries for older configurations to a submenu, allowing you to choose
15921 an older system generation at boot time should you need it.
15924 @c The paragraph below refers to the problem discussed at
15925 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
15926 It is highly recommended to run @command{guix pull} once before you run
15927 @command{guix system reconfigure} for the first time (@pxref{Invoking
15928 guix pull}). Failing to do that you would see an older version of Guix
15929 once @command{reconfigure} has completed.
15932 @item switch-generation
15933 @cindex generations
15934 Switch to an existing system generation. This action atomically
15935 switches the system profile to the specified system generation. It
15936 also rearranges the system's existing bootloader menu entries. It
15937 makes the menu entry for the specified system generation the default,
15938 and it moves the entries for the other generatiors to a submenu, if
15939 supported by the bootloader being used. The next time the system
15940 boots, it will use the specified system generation.
15942 The bootloader itself is not being reinstalled when using this
15943 command. Thus, the installed bootloader is used with an updated
15944 configuration file.
15946 The target generation can be specified explicitly by its generation
15947 number. For example, the following invocation would switch to system
15951 guix system switch-generation 7
15954 The target generation can also be specified relative to the current
15955 generation with the form @code{+N} or @code{-N}, where @code{+3} means
15956 ``3 generations ahead of the current generation,'' and @code{-1} means
15957 ``1 generation prior to the current generation.'' When specifying a
15958 negative value such as @code{-1}, you must precede it with @code{--} to
15959 prevent it from being parsed as an option. For example:
15962 guix system switch-generation -- -1
15965 Currently, the effect of invoking this action is @emph{only} to switch
15966 the system profile to an existing generation and rearrange the
15967 bootloader menu entries. To actually start using the target system
15968 generation, you must reboot after running this action. In the future,
15969 it will be updated to do the same things as @command{reconfigure},
15970 like activating and deactivating services.
15972 This action will fail if the specified generation does not exist.
15975 @cindex rolling back
15976 Switch to the preceding system generation. The next time the system
15977 boots, it will use the preceding system generation. This is the inverse
15978 of @command{reconfigure}, and it is exactly the same as invoking
15979 @command{switch-generation} with an argument of @code{-1}.
15981 Currently, as with @command{switch-generation}, you must reboot after
15982 running this action to actually start using the preceding system
15986 Build the derivation of the operating system, which includes all the
15987 configuration files and programs needed to boot and run the system.
15988 This action does not actually install anything.
15991 Populate the given directory with all the files necessary to run the
15992 operating system specified in @var{file}. This is useful for first-time
15993 installations of GuixSD. For instance:
15996 guix system init my-os-config.scm /mnt
15999 copies to @file{/mnt} all the store items required by the configuration
16000 specified in @file{my-os-config.scm}. This includes configuration
16001 files, packages, and so on. It also creates other essential files
16002 needed for the system to operate correctly---e.g., the @file{/etc},
16003 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
16005 This command also installs bootloader on the device specified in
16006 @file{my-os-config}, unless the @option{--no-bootloader} option was
16010 @cindex virtual machine
16012 @anchor{guix system vm}
16013 Build a virtual machine that contains the operating system declared in
16014 @var{file}, and return a script to run that virtual machine (VM).
16015 Arguments given to the script are passed to QEMU.
16017 The VM shares its store with the host system.
16019 Additional file systems can be shared between the host and the VM using
16020 the @code{--share} and @code{--expose} command-line options: the former
16021 specifies a directory to be shared with write access, while the latter
16022 provides read-only access to the shared directory.
16024 The example below creates a VM in which the user's home directory is
16025 accessible read-only, and where the @file{/exchange} directory is a
16026 read-write mapping of @file{$HOME/tmp} on the host:
16029 guix system vm my-config.scm \
16030 --expose=$HOME --share=$HOME/tmp=/exchange
16033 On GNU/Linux, the default is to boot directly to the kernel; this has
16034 the advantage of requiring only a very tiny root disk image since the
16035 store of the host can then be mounted.
16037 The @code{--full-boot} option forces a complete boot sequence, starting
16038 with the bootloader. This requires more disk space since a root image
16039 containing at least the kernel, initrd, and bootloader data files must
16040 be created. The @code{--image-size} option can be used to specify the
16045 Return a virtual machine or disk image of the operating system declared
16046 in @var{file} that stands alone. Use the @option{--image-size} option
16047 to specify the size of the image.
16049 When using @code{vm-image}, the returned image is in qcow2 format, which
16050 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
16051 for more information on how to run the image in a virtual machine.
16053 When using @code{disk-image}, a raw disk image is produced; it can be
16054 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
16055 the device corresponding to a USB stick, one can copy the image to it
16056 using the following command:
16059 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
16063 Return a script to run the operating system declared in @var{file}
16064 within a container. Containers are a set of lightweight isolation
16065 mechanisms provided by the kernel Linux-libre. Containers are
16066 substantially less resource-demanding than full virtual machines since
16067 the kernel, shared objects, and other resources can be shared with the
16068 host system; this also means they provide thinner isolation.
16070 Currently, the script must be run as root in order to support more than
16071 a single user and group. The container shares its store with the host
16074 As with the @code{vm} action (@pxref{guix system vm}), additional file
16075 systems to be shared between the host and container can be specified
16076 using the @option{--share} and @option{--expose} options:
16079 guix system container my-config.scm \
16080 --expose=$HOME --share=$HOME/tmp=/exchange
16084 This option requires Linux-libre 3.19 or newer.
16089 @var{options} can contain any of the common build options (@pxref{Common
16090 Build Options}). In addition, @var{options} can contain one of the
16094 @item --system=@var{system}
16095 @itemx -s @var{system}
16096 Attempt to build for @var{system} instead of the host system type.
16097 This works as per @command{guix build} (@pxref{Invoking guix build}).
16101 Return the derivation file name of the given operating system without
16104 @item --image-size=@var{size}
16105 For the @code{vm-image} and @code{disk-image} actions, create an image
16106 of the given @var{size}. @var{size} may be a number of bytes, or it may
16107 include a unit as a suffix (@pxref{Block size, size specifications,,
16108 coreutils, GNU Coreutils}).
16110 @item --root=@var{file}
16111 @itemx -r @var{file}
16112 Make @var{file} a symlink to the result, and register it as a garbage
16115 @item --on-error=@var{strategy}
16116 Apply @var{strategy} when an error occurs when reading @var{file}.
16117 @var{strategy} may be one of the following:
16120 @item nothing-special
16121 Report the error concisely and exit. This is the default strategy.
16124 Likewise, but also display a backtrace.
16127 Report the error and enter Guile's debugger. From there, you can run
16128 commands such as @code{,bt} to get a backtrace, @code{,locals} to
16129 display local variable values, and more generally inspect the state of the
16130 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
16131 a list of available debugging commands.
16136 All the actions above, except @code{build} and @code{init},
16137 can use KVM support in the Linux-libre kernel. Specifically, if the
16138 machine has hardware virtualization support, the corresponding
16139 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
16140 must exist and be readable and writable by the user and by the
16141 build users of the daemon (@pxref{Build Environment Setup}).
16144 Once you have built, configured, re-configured, and re-re-configured
16145 your GuixSD installation, you may find it useful to list the operating
16146 system generations available on disk---and that you can choose from the
16147 bootloader boot menu:
16151 @item list-generations
16152 List a summary of each generation of the operating system available on
16153 disk, in a human-readable way. This is similar to the
16154 @option{--list-generations} option of @command{guix package}
16155 (@pxref{Invoking guix package}).
16157 Optionally, one can specify a pattern, with the same syntax that is used
16158 in @command{guix package --list-generations}, to restrict the list of
16159 generations displayed. For instance, the following command displays
16160 generations that are up to 10 days old:
16163 $ guix system list-generations 10d
16168 The @command{guix system} command has even more to offer! The following
16169 sub-commands allow you to visualize how your system services relate to
16172 @anchor{system-extension-graph}
16175 @item extension-graph
16176 Emit in Dot/Graphviz format to standard output the @dfn{service
16177 extension graph} of the operating system defined in @var{file}
16178 (@pxref{Service Composition}, for more information on service
16184 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
16187 produces a PDF file showing the extension relations among services.
16189 @anchor{system-shepherd-graph}
16190 @item shepherd-graph
16191 Emit in Dot/Graphviz format to standard output the @dfn{dependency
16192 graph} of shepherd services of the operating system defined in
16193 @var{file}. @xref{Shepherd Services}, for more information and for an
16198 @node Running GuixSD in a VM
16199 @subsection Running GuixSD in a Virtual Machine
16201 @cindex virtual machine
16202 To run GuixSD in a virtual machine (VM), one can either use the
16203 pre-built GuixSD VM image distributed at
16204 @indicateurl{ftp://alpha.gnu.org/guix/guixsd-vm-image-@value{VERSION}.@var{system}.tar.xz}
16205 , or build their own virtual machine image using @command{guix system
16206 vm-image} (@pxref{Invoking guix system}). The returned image is in
16207 qcow2 format, which the @uref{http://qemu.org/, QEMU emulator} can
16211 If you built your own image, you must copy it out of the store
16212 (@pxref{The Store}) and give yourself permission to write to the copy
16213 before you can use it. When invoking QEMU, you must choose a system
16214 emulator that is suitable for your hardware platform. Here is a minimal
16215 QEMU invocation that will boot the result of @command{guix system
16216 vm-image} on x86_64 hardware:
16219 $ qemu-system-x86_64 \
16220 -net user -net nic,model=virtio \
16221 -enable-kvm -m 256 /tmp/qemu-image
16224 Here is what each of these options means:
16227 @item qemu-system-x86_64
16228 This specifies the hardware platform to emulate. This should match the
16232 Enable the unprivileged user-mode network stack. The guest OS can
16233 access the host but not vice versa. This is the simplest way to get the
16236 @item -net nic,model=virtio
16237 You must create a network interface of a given model. If you do not
16238 create a NIC, the boot will fail. Assuming your hardware platform is
16239 x86_64, you can get a list of available NIC models by running
16240 @command{qemu-system-x86_64 -net nic,model=help}.
16243 If your system has hardware virtualization extensions, enabling the
16244 virtual machine support (KVM) of the Linux kernel will make things run
16248 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
16249 which may be insufficient for some operations.
16251 @item /tmp/qemu-image
16252 The file name of the qcow2 image.
16255 The default @command{run-vm.sh} script that is returned by an invocation of
16256 @command{guix system vm} does not add a @command{-net user} flag by default.
16257 To get network access from within the vm add the @code{(dhcp-client-service)}
16258 to your system definition and start the VM using
16259 @command{`guix system vm config.scm` -net user}. An important caveat of using
16260 @command{-net user} for networking is that @command{ping} will not work, because
16261 it uses the ICMP protocol. You'll have to use a different command to check for
16262 network connectivity, for example @command{guix download}.
16264 @subsubsection Connecting Through SSH
16268 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
16269 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
16270 boot unsupervised. It requires you to type some characters to initialize the
16271 randomness generator. In addition you need to forward the SSH port, 22 by
16272 default, to the host. You can do this with
16275 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
16278 To connect to the VM you can run
16281 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
16284 The @command{-p} tells @command{ssh} the port you want to connect to.
16285 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
16286 every time you modify your @command{config.scm} file and the
16287 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
16288 connection to an unknown host every time you connect.
16290 @subsubsection Using @command{virt-viewer} with Spice
16292 As an alternative to the default @command{qemu} graphical client you can
16293 use the @command{remote-viewer} from the @command{virt-viewer} package. To
16294 connect pass the @command{-spice port=5930,disable-ticketing} flag to
16295 @command{qemu}. See previous section for further information on how to do this.
16297 Spice also allows you to do some nice stuff like share your clipboard with your
16298 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
16301 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
16302 -chardev spicevmc,name=vdagent,id=vdagent
16303 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
16304 name=com.redhat.spice.0
16307 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
16309 @node Defining Services
16310 @subsection Defining Services
16312 The previous sections show the available services and how one can combine
16313 them in an @code{operating-system} declaration. But how do we define
16314 them in the first place? And what is a service anyway?
16317 * Service Composition:: The model for composing services.
16318 * Service Types and Services:: Types and services.
16319 * Service Reference:: API reference.
16320 * Shepherd Services:: A particular type of service.
16323 @node Service Composition
16324 @subsubsection Service Composition
16328 Here we define a @dfn{service} as, broadly, something that extends the
16329 functionality of the operating system. Often a service is a process---a
16330 @dfn{daemon}---started when the system boots: a secure shell server, a
16331 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
16332 whose execution can be triggered by another daemon---e.g., an FTP server
16333 started by @command{inetd} or a D-Bus service activated by
16334 @command{dbus-daemon}. Occasionally, a service does not map to a
16335 daemon. For instance, the ``account'' service collects user accounts
16336 and makes sure they exist when the system runs; the ``udev'' service
16337 collects device management rules and makes them available to the eudev
16338 daemon; the @file{/etc} service populates the @file{/etc} directory
16341 @cindex service extensions
16342 GuixSD services are connected by @dfn{extensions}. For instance, the
16343 secure shell service @emph{extends} the Shepherd---the GuixSD
16344 initialization system, running as PID@tie{}1---by giving it the command
16345 lines to start and stop the secure shell daemon (@pxref{Networking
16346 Services, @code{lsh-service}}); the UPower service extends the D-Bus
16347 service by passing it its @file{.service} specification, and extends the
16348 udev service by passing it device management rules (@pxref{Desktop
16349 Services, @code{upower-service}}); the Guix daemon service extends the
16350 Shepherd by passing it the command lines to start and stop the daemon,
16351 and extends the account service by passing it a list of required build
16352 user accounts (@pxref{Base Services}).
16354 All in all, services and their ``extends'' relations form a directed
16355 acyclic graph (DAG). If we represent services as boxes and extensions
16356 as arrows, a typical system might provide something like this:
16358 @image{images/service-graph,,5in,Typical service extension graph.}
16360 @cindex system service
16361 At the bottom, we see the @dfn{system service}, which produces the
16362 directory containing everything to run and boot the system, as returned
16363 by the @command{guix system build} command. @xref{Service Reference},
16364 to learn about the other service types shown here.
16365 @xref{system-extension-graph, the @command{guix system extension-graph}
16366 command}, for information on how to generate this representation for a
16367 particular operating system definition.
16369 @cindex service types
16370 Technically, developers can define @dfn{service types} to express these
16371 relations. There can be any number of services of a given type on the
16372 system---for instance, a system running two instances of the GNU secure
16373 shell server (lsh) has two instances of @var{lsh-service-type}, with
16374 different parameters.
16376 The following section describes the programming interface for service
16377 types and services.
16379 @node Service Types and Services
16380 @subsubsection Service Types and Services
16382 A @dfn{service type} is a node in the DAG described above. Let us start
16383 with a simple example, the service type for the Guix build daemon
16384 (@pxref{Invoking guix-daemon}):
16387 (define guix-service-type
16391 (list (service-extension shepherd-root-service-type guix-shepherd-service)
16392 (service-extension account-service-type guix-accounts)
16393 (service-extension activation-service-type guix-activation)))
16394 (default-value (guix-configuration))))
16398 It defines three things:
16402 A name, whose sole purpose is to make inspection and debugging easier.
16405 A list of @dfn{service extensions}, where each extension designates the
16406 target service type and a procedure that, given the parameters of the
16407 service, returns a list of objects to extend the service of that type.
16409 Every service type has at least one service extension. The only
16410 exception is the @dfn{boot service type}, which is the ultimate service.
16413 Optionally, a default value for instances of this type.
16416 In this example, @var{guix-service-type} extends three services:
16419 @item shepherd-root-service-type
16420 The @var{guix-shepherd-service} procedure defines how the Shepherd
16421 service is extended. Namely, it returns a @code{<shepherd-service>}
16422 object that defines how @command{guix-daemon} is started and stopped
16423 (@pxref{Shepherd Services}).
16425 @item account-service-type
16426 This extension for this service is computed by @var{guix-accounts},
16427 which returns a list of @code{user-group} and @code{user-account}
16428 objects representing the build user accounts (@pxref{Invoking
16431 @item activation-service-type
16432 Here @var{guix-activation} is a procedure that returns a gexp, which is
16433 a code snippet to run at ``activation time''---e.g., when the service is
16437 A service of this type is instantiated like this:
16440 (service guix-service-type
16441 (guix-configuration
16443 (use-substitutes? #f)))
16446 The second argument to the @code{service} form is a value representing
16447 the parameters of this specific service instance.
16448 @xref{guix-configuration-type, @code{guix-configuration}}, for
16449 information about the @code{guix-configuration} data type. When the
16450 value is omitted, the default value specified by
16451 @code{guix-service-type} is used:
16454 (service guix-service-type)
16457 @var{guix-service-type} is quite simple because it extends other
16458 services but is not extensible itself.
16460 @c @subsubsubsection Extensible Service Types
16462 The service type for an @emph{extensible} service looks like this:
16465 (define udev-service-type
16466 (service-type (name 'udev)
16468 (list (service-extension shepherd-root-service-type
16469 udev-shepherd-service)))
16471 (compose concatenate) ;concatenate the list of rules
16472 (extend (lambda (config rules)
16474 (($ <udev-configuration> udev initial-rules)
16475 (udev-configuration
16476 (udev udev) ;the udev package to use
16477 (rules (append initial-rules rules)))))))))
16480 This is the service type for the
16481 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
16482 management daemon}. Compared to the previous example, in addition to an
16483 extension of @var{shepherd-root-service-type}, we see two new fields:
16487 This is the procedure to @dfn{compose} the list of extensions to
16488 services of this type.
16490 Services can extend the udev service by passing it lists of rules; we
16491 compose those extensions simply by concatenating them.
16494 This procedure defines how the value of the service is @dfn{extended} with
16495 the composition of the extensions.
16497 Udev extensions are composed into a list of rules, but the udev service
16498 value is itself a @code{<udev-configuration>} record. So here, we
16499 extend that record by appending the list of rules it contains to the
16500 list of contributed rules.
16503 There can be only one instance of an extensible service type such as
16504 @var{udev-service-type}. If there were more, the
16505 @code{service-extension} specifications would be ambiguous.
16507 Still here? The next section provides a reference of the programming
16508 interface for services.
16510 @node Service Reference
16511 @subsubsection Service Reference
16513 We have seen an overview of service types (@pxref{Service Types and
16514 Services}). This section provides a reference on how to manipulate
16515 services and service types. This interface is provided by the
16516 @code{(gnu services)} module.
16518 @deffn {Scheme Procedure} service @var{type} [@var{value}]
16519 Return a new service of @var{type}, a @code{<service-type>} object (see
16520 below.) @var{value} can be any object; it represents the parameters of
16521 this particular service instance.
16523 When @var{value} is omitted, the default value specified by @var{type}
16524 is used; if @var{type} does not specify a default value, an error is
16527 For instance, this:
16530 (service openssh-service-type)
16534 is equivalent to this:
16537 (service openssh-service-type
16538 (openssh-configuration))
16541 In both cases the result is an instance of @code{openssh-service-type}
16542 with the default configuration.
16545 @deffn {Scheme Procedure} service? @var{obj}
16546 Return true if @var{obj} is a service.
16549 @deffn {Scheme Procedure} service-kind @var{service}
16550 Return the type of @var{service}---i.e., a @code{<service-type>} object.
16553 @deffn {Scheme Procedure} service-value @var{service}
16554 Return the value associated with @var{service}. It represents its
16558 Here is an example of how a service is created and manipulated:
16562 (service nginx-service-type
16563 (nginx-configuration
16565 (log-directory log-directory)
16566 (run-directory run-directory)
16567 (file config-file))))
16572 (eq? (service-kind s) nginx-service-type)
16576 The @code{modify-services} form provides a handy way to change the
16577 parameters of some of the services of a list such as
16578 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
16579 evaluates to a list of services. Of course, you could always use
16580 standard list combinators such as @code{map} and @code{fold} to do that
16581 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
16582 @code{modify-services} simply provides a more concise form for this
16585 @deffn {Scheme Syntax} modify-services @var{services} @
16586 (@var{type} @var{variable} => @var{body}) @dots{}
16588 Modify the services listed in @var{services} according to the given
16589 clauses. Each clause has the form:
16592 (@var{type} @var{variable} => @var{body})
16595 where @var{type} is a service type---e.g.,
16596 @code{guix-service-type}---and @var{variable} is an identifier that is
16597 bound within the @var{body} to the service parameters---e.g., a
16598 @code{guix-configuration} instance---of the original service of that
16601 The @var{body} should evaluate to the new service parameters, which will
16602 be used to configure the new service. This new service will replace the
16603 original in the resulting list. Because a service's service parameters
16604 are created using @code{define-record-type*}, you can write a succinct
16605 @var{body} that evaluates to the new service parameters by using the
16606 @code{inherit} feature that @code{define-record-type*} provides.
16608 @xref{Using the Configuration System}, for example usage.
16612 Next comes the programming interface for service types. This is
16613 something you want to know when writing new service definitions, but not
16614 necessarily when simply looking for ways to customize your
16615 @code{operating-system} declaration.
16617 @deftp {Data Type} service-type
16618 @cindex service type
16619 This is the representation of a @dfn{service type} (@pxref{Service Types
16624 This is a symbol, used only to simplify inspection and debugging.
16626 @item @code{extensions}
16627 A non-empty list of @code{<service-extension>} objects (see below).
16629 @item @code{compose} (default: @code{#f})
16630 If this is @code{#f}, then the service type denotes services that cannot
16631 be extended---i.e., services that do not receive ``values'' from other
16634 Otherwise, it must be a one-argument procedure. The procedure is called
16635 by @code{fold-services} and is passed a list of values collected from
16636 extensions. It must return a value that is a valid parameter value for
16637 the service instance.
16639 @item @code{extend} (default: @code{#f})
16640 If this is @code{#f}, services of this type cannot be extended.
16642 Otherwise, it must be a two-argument procedure: @code{fold-services}
16643 calls it, passing it the initial value of the service as the first argument
16644 and the result of applying @code{compose} to the extension values as the
16648 @xref{Service Types and Services}, for examples.
16651 @deffn {Scheme Procedure} service-extension @var{target-type} @
16653 Return a new extension for services of type @var{target-type}.
16654 @var{compute} must be a one-argument procedure: @code{fold-services}
16655 calls it, passing it the value associated with the service that provides
16656 the extension; it must return a valid value for the target service.
16659 @deffn {Scheme Procedure} service-extension? @var{obj}
16660 Return true if @var{obj} is a service extension.
16663 Occasionally, you might want to simply extend an existing service. This
16664 involves creating a new service type and specifying the extension of
16665 interest, which can be verbose; the @code{simple-service} procedure
16666 provides a shorthand for this.
16668 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
16669 Return a service that extends @var{target} with @var{value}. This works
16670 by creating a singleton service type @var{name}, of which the returned
16671 service is an instance.
16673 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
16677 (simple-service 'my-mcron-job mcron-service-type
16678 #~(job '(next-hour (3)) "guix gc -F 2G"))
16682 At the core of the service abstraction lies the @code{fold-services}
16683 procedure, which is responsible for ``compiling'' a list of services
16684 down to a single directory that contains everything needed to boot and
16685 run the system---the directory shown by the @command{guix system build}
16686 command (@pxref{Invoking guix system}). In essence, it propagates
16687 service extensions down the service graph, updating each node parameters
16688 on the way, until it reaches the root node.
16690 @deffn {Scheme Procedure} fold-services @var{services} @
16691 [#:target-type @var{system-service-type}]
16692 Fold @var{services} by propagating their extensions down to the root of
16693 type @var{target-type}; return the root service adjusted accordingly.
16696 Lastly, the @code{(gnu services)} module also defines several essential
16697 service types, some of which are listed below.
16699 @defvr {Scheme Variable} system-service-type
16700 This is the root of the service graph. It produces the system directory
16701 as returned by the @command{guix system build} command.
16704 @defvr {Scheme Variable} boot-service-type
16705 The type of the ``boot service'', which produces the @dfn{boot script}.
16706 The boot script is what the initial RAM disk runs when booting.
16709 @defvr {Scheme Variable} etc-service-type
16710 The type of the @file{/etc} service. This service can be extended by
16711 passing it name/file tuples such as:
16714 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
16717 In this example, the effect would be to add an @file{/etc/issue} file
16718 pointing to the given file.
16721 @defvr {Scheme Variable} setuid-program-service-type
16722 Type for the ``setuid-program service''. This service collects lists of
16723 executable file names, passed as gexps, and adds them to the set of
16724 setuid-root programs on the system (@pxref{Setuid Programs}).
16727 @defvr {Scheme Variable} profile-service-type
16728 Type of the service that populates the @dfn{system profile}---i.e., the
16729 programs under @file{/run/current-system/profile}. Other services can
16730 extend it by passing it lists of packages to add to the system profile.
16734 @node Shepherd Services
16735 @subsubsection Shepherd Services
16737 @cindex shepherd services
16739 @cindex init system
16740 The @code{(gnu services shepherd)} module provides a way to define
16741 services managed by the GNU@tie{}Shepherd, which is the GuixSD
16742 initialization system---the first process that is started when the
16743 system boots, also known as PID@tie{}1
16744 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
16746 Services in the Shepherd can depend on each other. For instance, the
16747 SSH daemon may need to be started after the syslog daemon has been
16748 started, which in turn can only happen once all the file systems have
16749 been mounted. The simple operating system defined earlier (@pxref{Using
16750 the Configuration System}) results in a service graph like this:
16752 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
16754 You can actually generate such a graph for any operating system
16755 definition using the @command{guix system shepherd-graph} command
16756 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
16758 The @var{%shepherd-root-service} is a service object representing
16759 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
16760 by passing it lists of @code{<shepherd-service>} objects.
16762 @deftp {Data Type} shepherd-service
16763 The data type representing a service managed by the Shepherd.
16766 @item @code{provision}
16767 This is a list of symbols denoting what the service provides.
16769 These are the names that may be passed to @command{herd start},
16770 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
16771 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
16772 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
16774 @item @code{requirements} (default: @code{'()})
16775 List of symbols denoting the Shepherd services this one depends on.
16777 @item @code{respawn?} (default: @code{#t})
16778 Whether to restart the service when it stops, for instance when the
16779 underlying process dies.
16782 @itemx @code{stop} (default: @code{#~(const #f)})
16783 The @code{start} and @code{stop} fields refer to the Shepherd's
16784 facilities to start and stop processes (@pxref{Service De- and
16785 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
16786 G-expressions that get expanded in the Shepherd configuration file
16787 (@pxref{G-Expressions}).
16789 @item @code{documentation}
16790 A documentation string, as shown when running:
16793 herd doc @var{service-name}
16796 where @var{service-name} is one of the symbols in @var{provision}
16797 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
16799 @item @code{modules} (default: @var{%default-modules})
16800 This is the list of modules that must be in scope when @code{start} and
16801 @code{stop} are evaluated.
16806 @defvr {Scheme Variable} shepherd-root-service-type
16807 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
16809 This is the service type that extensions target when they want to create
16810 shepherd services (@pxref{Service Types and Services}, for an example).
16811 Each extension must pass a list of @code{<shepherd-service>}.
16814 @defvr {Scheme Variable} %shepherd-root-service
16815 This service represents PID@tie{}1.
16819 @node Documentation
16820 @section Documentation
16822 @cindex documentation, searching for
16823 @cindex searching for documentation
16824 @cindex Info, documentation format
16826 @cindex manual pages
16827 In most cases packages installed with Guix come with documentation.
16828 There are two main documentation formats: ``Info'', a browseable
16829 hypertext format used for GNU software, and ``manual pages'' (or ``man
16830 pages''), the linear documentation format traditionally found on Unix.
16831 Info manuals are accessed with the @command{info} command or with Emacs,
16832 and man pages are accessed using @command{man}.
16834 You can look for documentation of software installed on your system by
16835 keyword. For example, the following command searches for information
16836 about ``TLS'' in Info manuals:
16840 "(emacs)Network Security" -- STARTTLS
16841 "(emacs)Network Security" -- TLS
16842 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
16843 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
16848 The command below searches for the same keyword in man pages:
16852 SSL (7) - OpenSSL SSL/TLS library
16853 certtool (1) - GnuTLS certificate tool
16857 These searches are purely local to your computer so you have the
16858 guarantee that documentation you find corresponds to what you have
16859 actually installed, you can access it off-line, and your privacy is
16862 Once you have these results, you can view the relevant documentation by
16866 $ info "(gnutls)Core TLS API"
16876 Info manuals contain sections and indices as well as hyperlinks like
16877 those found in Web pages. The @command{info} reader (@pxref{Top, Info
16878 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
16879 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
16880 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
16881 Introduction}, for an introduction to Info navigation.
16883 @node Installing Debugging Files
16884 @section Installing Debugging Files
16886 @cindex debugging files
16887 Program binaries, as produced by the GCC compilers for instance, are
16888 typically written in the ELF format, with a section containing
16889 @dfn{debugging information}. Debugging information is what allows the
16890 debugger, GDB, to map binary code to source code; it is required to
16891 debug a compiled program in good conditions.
16893 The problem with debugging information is that is takes up a fair amount
16894 of disk space. For example, debugging information for the GNU C Library
16895 weighs in at more than 60 MiB. Thus, as a user, keeping all the
16896 debugging info of all the installed programs is usually not an option.
16897 Yet, space savings should not come at the cost of an impediment to
16898 debugging---especially in the GNU system, which should make it easier
16899 for users to exert their computing freedom (@pxref{GNU Distribution}).
16901 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
16902 mechanism that allows users to get the best of both worlds: debugging
16903 information can be stripped from the binaries and stored in separate
16904 files. GDB is then able to load debugging information from those files,
16905 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
16908 The GNU distribution takes advantage of this by storing debugging
16909 information in the @code{lib/debug} sub-directory of a separate package
16910 output unimaginatively called @code{debug} (@pxref{Packages with
16911 Multiple Outputs}). Users can choose to install the @code{debug} output
16912 of a package when they need it. For instance, the following command
16913 installs the debugging information for the GNU C Library and for GNU
16917 guix package -i glibc:debug guile:debug
16920 GDB must then be told to look for debug files in the user's profile, by
16921 setting the @code{debug-file-directory} variable (consider setting it
16922 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
16926 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
16929 From there on, GDB will pick up debugging information from the
16930 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
16932 In addition, you will most likely want GDB to be able to show the source
16933 code being debugged. To do that, you will have to unpack the source
16934 code of the package of interest (obtained with @code{guix build
16935 --source}, @pxref{Invoking guix build}), and to point GDB to that source
16936 directory using the @code{directory} command (@pxref{Source Path,
16937 @code{directory},, gdb, Debugging with GDB}).
16939 @c XXX: keep me up-to-date
16940 The @code{debug} output mechanism in Guix is implemented by the
16941 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
16942 opt-in---debugging information is available only for the packages
16943 with definitions explicitly declaring a @code{debug} output. This may be
16944 changed to opt-out in the future if our build farm servers can handle
16945 the load. To check whether a package has a @code{debug} output, use
16946 @command{guix package --list-available} (@pxref{Invoking guix package}).
16949 @node Security Updates
16950 @section Security Updates
16952 @cindex security updates
16953 @cindex security vulnerabilities
16954 Occasionally, important security vulnerabilities are discovered in software
16955 packages and must be patched. Guix developers try hard to keep track of
16956 known vulnerabilities and to apply fixes as soon as possible in the
16957 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
16958 containing only security updates.) The @command{guix lint} tool helps
16959 developers find out about vulnerable versions of software packages in the
16964 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
16965 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
16966 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
16970 @xref{Invoking guix lint}, for more information.
16973 As of version @value{VERSION}, the feature described below is considered
16977 Guix follows a functional
16978 package management discipline (@pxref{Introduction}), which implies
16979 that, when a package is changed, @emph{every package that depends on it}
16980 must be rebuilt. This can significantly slow down the deployment of
16981 fixes in core packages such as libc or Bash, since basically the whole
16982 distribution would need to be rebuilt. Using pre-built binaries helps
16983 (@pxref{Substitutes}), but deployment may still take more time than
16987 To address this, Guix implements @dfn{grafts}, a mechanism that allows
16988 for fast deployment of critical updates without the costs associated
16989 with a whole-distribution rebuild. The idea is to rebuild only the
16990 package that needs to be patched, and then to ``graft'' it onto packages
16991 explicitly installed by the user and that were previously referring to
16992 the original package. The cost of grafting is typically very low, and
16993 order of magnitudes lower than a full rebuild of the dependency chain.
16995 @cindex replacements of packages, for grafts
16996 For instance, suppose a security update needs to be applied to Bash.
16997 Guix developers will provide a package definition for the ``fixed''
16998 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
16999 Packages}). Then, the original package definition is augmented with a
17000 @code{replacement} field pointing to the package containing the bug fix:
17007 (replacement bash-fixed)))
17010 From there on, any package depending directly or indirectly on Bash---as
17011 reported by @command{guix gc --requisites} (@pxref{Invoking guix
17012 gc})---that is installed is automatically ``rewritten'' to refer to
17013 @var{bash-fixed} instead of @var{bash}. This grafting process takes
17014 time proportional to the size of the package, usually less than a
17015 minute for an ``average'' package on a recent machine. Grafting is
17016 recursive: when an indirect dependency requires grafting, then grafting
17017 ``propagates'' up to the package that the user is installing.
17019 Currently, the length of the name and version of the graft and that of
17020 the package it replaces (@var{bash-fixed} and @var{bash} in the example
17021 above) must be equal. This restriction mostly comes from the fact that
17022 grafting works by patching files, including binary files, directly.
17023 Other restrictions may apply: for instance, when adding a graft to a
17024 package providing a shared library, the original shared library and its
17025 replacement must have the same @code{SONAME} and be binary-compatible.
17027 The @option{--no-grafts} command-line option allows you to forcefully
17028 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
17032 guix build bash --no-grafts
17036 returns the store file name of the original Bash, whereas:
17043 returns the store file name of the ``fixed'', replacement Bash. This
17044 allows you to distinguish between the two variants of Bash.
17046 To verify which Bash your whole profile refers to, you can run
17047 (@pxref{Invoking guix gc}):
17050 guix gc -R `readlink -f ~/.guix-profile` | grep bash
17054 @dots{} and compare the store file names that you get with those above.
17055 Likewise for a complete GuixSD system generation:
17058 guix gc -R `guix system build my-config.scm` | grep bash
17061 Lastly, to check which Bash running processes are using, you can use the
17062 @command{lsof} command:
17065 lsof | grep /gnu/store/.*bash
17069 @node Package Modules
17070 @section Package Modules
17072 From a programming viewpoint, the package definitions of the
17073 GNU distribution are provided by Guile modules in the @code{(gnu packages
17074 @dots{})} name space@footnote{Note that packages under the @code{(gnu
17075 packages @dots{})} module name space are not necessarily ``GNU
17076 packages''. This module naming scheme follows the usual Guile module
17077 naming convention: @code{gnu} means that these modules are distributed
17078 as part of the GNU system, and @code{packages} identifies modules that
17079 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
17080 Reference Manual}). For instance, the @code{(gnu packages emacs)}
17081 module exports a variable named @code{emacs}, which is bound to a
17082 @code{<package>} object (@pxref{Defining Packages}).
17084 The @code{(gnu packages @dots{})} module name space is
17085 automatically scanned for packages by the command-line tools. For
17086 instance, when running @code{guix package -i emacs}, all the @code{(gnu
17087 packages @dots{})} modules are scanned until one that exports a package
17088 object whose name is @code{emacs} is found. This package search
17089 facility is implemented in the @code{(gnu packages)} module.
17091 @cindex customization, of packages
17092 @cindex package module search path
17093 Users can store package definitions in modules with different
17094 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
17095 name and module name must match. For instance, the @code{(my-packages
17096 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
17097 relative to the load path specified with @option{--load-path} or
17098 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
17099 guile, GNU Guile Reference Manual}, for details.}. These package definitions
17100 will not be visible by default. Users can invoke commands such as
17101 @command{guix package} and @command{guix build} with the
17102 @code{-e} option so that they know where to find the package. Better
17103 yet, they can use the
17104 @code{-L} option of these commands to make those modules visible
17105 (@pxref{Invoking guix build, @code{--load-path}}), or define the
17106 @code{GUIX_PACKAGE_PATH} environment variable. This environment
17107 variable makes it easy to extend or customize the distribution and is
17108 honored by all the user interfaces.
17110 @defvr {Environment Variable} GUIX_PACKAGE_PATH
17111 This is a colon-separated list of directories to search for additional
17112 package modules. Directories listed in this variable take precedence
17113 over the own modules of the distribution.
17116 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
17117 each package is built based solely on other packages in the
17118 distribution. The root of this dependency graph is a small set of
17119 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
17120 bootstrap)} module. For more information on bootstrapping,
17121 @pxref{Bootstrapping}.
17123 @node Packaging Guidelines
17124 @section Packaging Guidelines
17126 @cindex packages, creating
17127 The GNU distribution is nascent and may well lack some of your favorite
17128 packages. This section describes how you can help make the distribution
17129 grow. @xref{Contributing}, for additional information on how you can
17132 Free software packages are usually distributed in the form of
17133 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
17134 all the source files. Adding a package to the distribution means
17135 essentially two things: adding a @dfn{recipe} that describes how to
17136 build the package, including a list of other packages required to build
17137 it, and adding @dfn{package metadata} along with that recipe, such as a
17138 description and licensing information.
17140 In Guix all this information is embodied in @dfn{package definitions}.
17141 Package definitions provide a high-level view of the package. They are
17142 written using the syntax of the Scheme programming language; in fact,
17143 for each package we define a variable bound to the package definition,
17144 and export that variable from a module (@pxref{Package Modules}).
17145 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
17146 creating packages. For more information on package definitions,
17147 @pxref{Defining Packages}.
17149 Once a package definition is in place, stored in a file in the Guix
17150 source tree, it can be tested using the @command{guix build} command
17151 (@pxref{Invoking guix build}). For example, assuming the new package is
17152 called @code{gnew}, you may run this command from the Guix build tree
17153 (@pxref{Running Guix Before It Is Installed}):
17156 ./pre-inst-env guix build gnew --keep-failed
17159 Using @code{--keep-failed} makes it easier to debug build failures since
17160 it provides access to the failed build tree. Another useful
17161 command-line option when debugging is @code{--log-file}, to access the
17164 If the package is unknown to the @command{guix} command, it may be that
17165 the source file contains a syntax error, or lacks a @code{define-public}
17166 clause to export the package variable. To figure it out, you may load
17167 the module from Guile to get more information about the actual error:
17170 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
17173 Once your package builds correctly, please send us a patch
17174 (@pxref{Contributing}). Well, if you need help, we will be happy to
17175 help you too. Once the patch is committed in the Guix repository, the
17176 new package automatically gets built on the supported platforms by
17177 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
17180 @cindex substituter
17181 Users can obtain the new package definition simply by running
17182 @command{guix pull} (@pxref{Invoking guix pull}). When
17183 @code{hydra.gnu.org} is done building the package, installing the
17184 package automatically downloads binaries from there
17185 (@pxref{Substitutes}). The only place where human intervention is
17186 needed is to review and apply the patch.
17190 * Software Freedom:: What may go into the distribution.
17191 * Package Naming:: What's in a name?
17192 * Version Numbers:: When the name is not enough.
17193 * Synopses and Descriptions:: Helping users find the right package.
17194 * Python Modules:: A touch of British comedy.
17195 * Perl Modules:: Little pearls.
17196 * Java Packages:: Coffee break.
17197 * Fonts:: Fond of fonts.
17200 @node Software Freedom
17201 @subsection Software Freedom
17203 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
17204 @cindex free software
17205 The GNU operating system has been developed so that users can have
17206 freedom in their computing. GNU is @dfn{free software}, meaning that
17207 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
17208 essential freedoms}: to run the program, to study and change the program
17209 in source code form, to redistribute exact copies, and to distribute
17210 modified versions. Packages found in the GNU distribution provide only
17211 software that conveys these four freedoms.
17213 In addition, the GNU distribution follow the
17214 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
17215 software distribution guidelines}. Among other things, these guidelines
17216 reject non-free firmware, recommendations of non-free software, and
17217 discuss ways to deal with trademarks and patents.
17219 Some otherwise free upstream package sources contain a small and optional
17220 subset that violates the above guidelines, for instance because this subset
17221 is itself non-free code. When that happens, the offending items are removed
17222 with appropriate patches or code snippets in the @code{origin} form of the
17223 package (@pxref{Defining Packages}). This way, @code{guix
17224 build --source} returns the ``freed'' source rather than the unmodified
17228 @node Package Naming
17229 @subsection Package Naming
17231 @cindex package name
17232 A package has actually two names associated with it:
17233 First, there is the name of the @emph{Scheme variable}, the one following
17234 @code{define-public}. By this name, the package can be made known in the
17235 Scheme code, for instance as input to another package. Second, there is
17236 the string in the @code{name} field of a package definition. This name
17237 is used by package management commands such as
17238 @command{guix package} and @command{guix build}.
17240 Both are usually the same and correspond to the lowercase conversion of
17241 the project name chosen upstream, with underscores replaced with
17242 hyphens. For instance, GNUnet is available as @code{gnunet}, and
17243 SDL_net as @code{sdl-net}.
17245 We do not add @code{lib} prefixes for library packages, unless these are
17246 already part of the official project name. But @pxref{Python
17247 Modules} and @ref{Perl Modules} for special rules concerning modules for
17248 the Python and Perl languages.
17250 Font package names are handled differently, @pxref{Fonts}.
17253 @node Version Numbers
17254 @subsection Version Numbers
17256 @cindex package version
17257 We usually package only the latest version of a given free software
17258 project. But sometimes, for instance for incompatible library versions,
17259 two (or more) versions of the same package are needed. These require
17260 different Scheme variable names. We use the name as defined
17261 in @ref{Package Naming}
17262 for the most recent version; previous versions use the same name, suffixed
17263 by @code{-} and the smallest prefix of the version number that may
17264 distinguish the two versions.
17266 The name inside the package definition is the same for all versions of a
17267 package and does not contain any version number.
17269 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
17272 (define-public gtk+
17277 (define-public gtk+-2
17280 (version "2.24.20")
17283 If we also wanted GTK+ 3.8.2, this would be packaged as
17285 (define-public gtk+-3.8
17292 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
17293 @c for a discussion of what follows.
17294 @cindex version number, for VCS snapshots
17295 Occasionally, we package snapshots of upstream's version control system
17296 (VCS) instead of formal releases. This should remain exceptional,
17297 because it is up to upstream developers to clarify what the stable
17298 release is. Yet, it is sometimes necessary. So, what should we put in
17299 the @code{version} field?
17301 Clearly, we need to make the commit identifier of the VCS snapshot
17302 visible in the version string, but we also need to make sure that the
17303 version string is monotonically increasing so that @command{guix package
17304 --upgrade} can determine which version is newer. Since commit
17305 identifiers, notably with Git, are not monotonically increasing, we add
17306 a revision number that we increase each time we upgrade to a newer
17307 snapshot. The resulting version string looks like this:
17312 | | `-- upstream commit ID
17314 | `--- Guix package revision
17316 latest upstream version
17319 It is a good idea to strip commit identifiers in the @code{version}
17320 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
17321 aesthetics have a role to play here) as well as problems related to OS
17322 limits such as the maximum shebang length (127 bytes for the Linux
17323 kernel.) It is best to use the full commit identifiers in
17324 @code{origin}s, though, to avoid ambiguities. A typical package
17325 definition may look like this:
17329 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
17330 (revision "1")) ;Guix package revision
17332 (version (string-append "0.9-" revision "."
17333 (string-take commit 7)))
17336 (uri (git-reference
17337 (url "git://example.org/my-package.git")
17339 (sha256 (base32 "1mbikn@dots{}"))
17340 (file-name (string-append "my-package-" version
17346 @node Synopses and Descriptions
17347 @subsection Synopses and Descriptions
17349 @cindex package description
17350 @cindex package synopsis
17351 As we have seen before, each package in GNU@tie{}Guix includes a
17352 synopsis and a description (@pxref{Defining Packages}). Synopses and
17353 descriptions are important: They are what @command{guix package
17354 --search} searches, and a crucial piece of information to help users
17355 determine whether a given package suits their needs. Consequently,
17356 packagers should pay attention to what goes into them.
17358 Synopses must start with a capital letter and must not end with a
17359 period. They must not start with ``a'' or ``the'', which usually does
17360 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
17361 tool that frobs files''. The synopsis should say what the package
17362 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
17363 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
17364 matching a pattern''.
17366 Keep in mind that the synopsis must be meaningful for a very wide
17367 audience. For example, ``Manipulate alignments in the SAM format''
17368 might make sense for a seasoned bioinformatics researcher, but might be
17369 fairly unhelpful or even misleading to a non-specialized audience. It
17370 is a good idea to come up with a synopsis that gives an idea of the
17371 application domain of the package. In this example, this might give
17372 something like ``Manipulate nucleotide sequence alignments'', which
17373 hopefully gives the user a better idea of whether this is what they are
17376 Descriptions should take between five and ten lines. Use full
17377 sentences, and avoid using acronyms without first introducing them.
17378 Please avoid marketing phrases such as ``world-leading'',
17379 ``industrial-strength'', and ``next-generation'', and avoid superlatives
17380 like ``the most advanced''---they are not helpful to users looking for a
17381 package and may even sound suspicious. Instead, try to be factual,
17382 mentioning use cases and features.
17384 @cindex Texinfo markup, in package descriptions
17385 Descriptions can include Texinfo markup, which is useful to introduce
17386 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
17387 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
17388 should be careful when using some characters for example @samp{@@} and
17389 curly braces which are the basic special characters in Texinfo
17390 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
17391 such as @command{guix package --show} take care of rendering it
17394 Synopses and descriptions are translated by volunteers
17395 @uref{http://translationproject.org/domain/guix-packages.html, at the
17396 Translation Project} so that as many users as possible can read them in
17397 their native language. User interfaces search them and display them in
17398 the language specified by the current locale.
17400 Translation is a lot of work so, as a packager, please pay even more
17401 attention to your synopses and descriptions as every change may entail
17402 additional work for translators. In order to help them, it is possible
17403 to make recommendations or instructions visible to them by inserting
17404 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
17408 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
17409 (description "ARandR is designed to provide a simple visual front end
17410 for the X11 resize-and-rotate (RandR) extension. @dots{}")
17414 @node Python Modules
17415 @subsection Python Modules
17418 We currently package Python 2 and Python 3, under the Scheme variable names
17419 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
17420 To avoid confusion and naming clashes with other programming languages, it
17421 seems desirable that the name of a package for a Python module contains
17422 the word @code{python}.
17424 Some modules are compatible with only one version of Python, others with both.
17425 If the package Foo compiles only with Python 3, we name it
17426 @code{python-foo}; if it compiles only with Python 2, we name it
17427 @code{python2-foo}. If it is compatible with both versions, we create two
17428 packages with the corresponding names.
17430 If a project already contains the word @code{python}, we drop this;
17431 for instance, the module python-dateutil is packaged under the names
17432 @code{python-dateutil} and @code{python2-dateutil}. If the project name
17433 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
17436 @subsubsection Specifying Dependencies
17437 @cindex inputs, for Python packages
17439 Dependency information for Python packages is usually available in the
17440 package source tree, with varying degrees of accuracy: in the
17441 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
17443 Your mission, when writing a recipe for a Python package, is to map
17444 these dependencies to the appropriate type of ``input'' (@pxref{package
17445 Reference, inputs}). Although the @code{pypi} importer normally does a
17446 good job (@pxref{Invoking guix import}), you may want to check the
17447 following check list to determine which dependency goes where.
17452 We currently package Python 2 with @code{setuptools} and @code{pip}
17453 installed like Python 3.4 has per default. Thus you don't need to
17454 specify either of these as an input. @command{guix lint} will warn you
17458 Python dependencies required at run time go into
17459 @code{propagated-inputs}. They are typically defined with the
17460 @code{install_requires} keyword in @file{setup.py}, or in the
17461 @file{requirements.txt} file.
17464 Python packages required only at build time---e.g., those listed with
17465 the @code{setup_requires} keyword in @file{setup.py}---or only for
17466 testing---e.g., those in @code{tests_require}---go into
17467 @code{native-inputs}. The rationale is that (1) they do not need to be
17468 propagated because they are not needed at run time, and (2) in a
17469 cross-compilation context, it's the ``native'' input that we'd want.
17471 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
17472 frameworks. Of course if any of these packages is also required at
17473 run-time, it needs to go to @code{propagated-inputs}.
17476 Anything that does not fall in the previous categories goes to
17477 @code{inputs}, for example programs or C libraries required for building
17478 Python packages containing C extensions.
17481 If a Python package has optional dependencies (@code{extras_require}),
17482 it is up to you to decide whether to add them or not, based on their
17483 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
17490 @subsection Perl Modules
17493 Perl programs standing for themselves are named as any other package,
17494 using the lowercase upstream name.
17495 For Perl packages containing a single class, we use the lowercase class name,
17496 replace all occurrences of @code{::} by dashes and prepend the prefix
17498 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
17499 Modules containing several classes keep their lowercase upstream name and
17500 are also prepended by @code{perl-}. Such modules tend to have the word
17501 @code{perl} somewhere in their name, which gets dropped in favor of the
17502 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
17505 @node Java Packages
17506 @subsection Java Packages
17509 Java programs standing for themselves are named as any other package,
17510 using the lowercase upstream name.
17512 To avoid confusion and naming clashes with other programming languages,
17513 it is desirable that the name of a package for a Java package is
17514 prefixed with @code{java-}. If a project already contains the word
17515 @code{java}, we drop this; for instance, the package @code{ngsjava} is
17516 packaged under the name @code{java-ngs}.
17518 For Java packages containing a single class or a small class hierarchy,
17519 we use the lowercase class name, replace all occurrences of @code{.} by
17520 dashes and prepend the prefix @code{java-}. So the class
17521 @code{apache.commons.cli} becomes package
17522 @code{java-apache-commons-cli}.
17529 For fonts that are in general not installed by a user for typesetting
17530 purposes, or that are distributed as part of a larger software package,
17531 we rely on the general packaging rules for software; for instance, this
17532 applies to the fonts delivered as part of the X.Org system or fonts that
17533 are part of TeX Live.
17535 To make it easier for a user to search for fonts, names for other packages
17536 containing only fonts are constructed as follows, independently of the
17537 upstream package name.
17539 The name of a package containing only one font family starts with
17540 @code{font-}; it is followed by the foundry name and a dash @code{-}
17541 if the foundry is known, and the font family name, in which spaces are
17542 replaced by dashes (and as usual, all upper case letters are transformed
17544 For example, the Gentium font family by SIL is packaged under the name
17545 @code{font-sil-gentium}.
17547 For a package containing several font families, the name of the collection
17548 is used in the place of the font family name.
17549 For instance, the Liberation fonts consist of three families,
17550 Liberation Sans, Liberation Serif and Liberation Mono.
17551 These could be packaged separately under the names
17552 @code{font-liberation-sans} and so on; but as they are distributed together
17553 under a common name, we prefer to package them together as
17554 @code{font-liberation}.
17556 In the case where several formats of the same font family or font collection
17557 are packaged separately, a short form of the format, prepended by a dash,
17558 is added to the package name. We use @code{-ttf} for TrueType fonts,
17559 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
17564 @node Bootstrapping
17565 @section Bootstrapping
17567 @c Adapted from the ELS 2013 paper.
17569 @cindex bootstrapping
17571 Bootstrapping in our context refers to how the distribution gets built
17572 ``from nothing''. Remember that the build environment of a derivation
17573 contains nothing but its declared inputs (@pxref{Introduction}). So
17574 there's an obvious chicken-and-egg problem: how does the first package
17575 get built? How does the first compiler get compiled? Note that this is
17576 a question of interest only to the curious hacker, not to the regular
17577 user, so you can shamelessly skip this section if you consider yourself
17578 a ``regular user''.
17580 @cindex bootstrap binaries
17581 The GNU system is primarily made of C code, with libc at its core. The
17582 GNU build system itself assumes the availability of a Bourne shell and
17583 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
17584 `grep'. Furthermore, build programs---programs that run
17585 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
17586 (@pxref{Derivations}). Consequently, to be able to build anything at
17587 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
17588 Binutils, libc, and the other packages mentioned above---the
17589 @dfn{bootstrap binaries}.
17591 These bootstrap binaries are ``taken for granted'', though we can also
17592 re-create them if needed (more on that later).
17594 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
17596 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
17597 @c large image, it's hard to scroll. Oh well.
17598 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
17600 The figure above shows the very beginning of the dependency graph of the
17601 distribution, corresponding to the package definitions of the @code{(gnu
17602 packages bootstrap)} module. A similar figure can be generated with
17603 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
17606 guix graph -t derivation \
17607 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
17611 At this level of detail, things are
17612 slightly complex. First, Guile itself consists of an ELF executable,
17613 along with many source and compiled Scheme files that are dynamically
17614 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
17615 tarball shown in this graph. This tarball is part of Guix's ``source''
17616 distribution, and gets inserted into the store with @code{add-to-store}
17617 (@pxref{The Store}).
17619 But how do we write a derivation that unpacks this tarball and adds it
17620 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
17621 derivation---the first one that gets built---uses @code{bash} as its
17622 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
17623 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
17624 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
17625 the Guix source distribution, whose sole purpose is to allow the Guile
17626 tarball to be unpacked.
17628 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
17629 Guile that can be used to run subsequent build programs. Its first task
17630 is to download tarballs containing the other pre-built binaries---this
17631 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
17632 @code{ftp-client.scm} are used for this purpose. The
17633 @code{module-import.drv} derivations import those modules in a directory
17634 in the store, using the original layout. The
17635 @code{module-import-compiled.drv} derivations compile those modules, and
17636 write them in an output directory with the right layout. This
17637 corresponds to the @code{#:modules} argument of
17638 @code{build-expression->derivation} (@pxref{Derivations}).
17640 Finally, the various tarballs are unpacked by the
17641 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
17642 etc., at which point we have a working C tool chain.
17645 @unnumberedsubsec Building the Build Tools
17647 Bootstrapping is complete when we have a full tool chain that does not
17648 depend on the pre-built bootstrap tools discussed above. This
17649 no-dependency requirement is verified by checking whether the files of
17650 the final tool chain contain references to the @file{/gnu/store}
17651 directories of the bootstrap inputs. The process that leads to this
17652 ``final'' tool chain is described by the package definitions found in
17653 the @code{(gnu packages commencement)} module.
17655 The @command{guix graph} command allows us to ``zoom out'' compared to
17656 the graph above, by looking at the level of package objects instead of
17657 individual derivations---remember that a package may translate to
17658 several derivations, typically one derivation to download its source,
17659 one to build the Guile modules it needs, and one to actually build the
17660 package from source. The command:
17663 guix graph -t bag \
17664 -e '(@@@@ (gnu packages commencement)
17665 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
17669 produces the dependency graph leading to the ``final'' C
17670 library@footnote{You may notice the @code{glibc-intermediate} label,
17671 suggesting that it is not @emph{quite} final, but as a good
17672 approximation, we will consider it final.}, depicted below.
17674 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
17676 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
17677 The first tool that gets built with the bootstrap binaries is
17678 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
17679 for all the following packages. From there Findutils and Diffutils get
17682 Then come the first-stage Binutils and GCC, built as pseudo cross
17683 tools---i.e., with @code{--target} equal to @code{--host}. They are
17684 used to build libc. Thanks to this cross-build trick, this libc is
17685 guaranteed not to hold any reference to the initial tool chain.
17687 From there the final Binutils and GCC (not shown above) are built.
17689 from the final Binutils, and links programs against the just-built libc.
17690 This tool chain is used to build the other packages used by Guix and by
17691 the GNU Build System: Guile, Bash, Coreutils, etc.
17693 And voilà! At this point we have the complete set of build tools that
17694 the GNU Build System expects. These are in the @code{%final-inputs}
17695 variable of the @code{(gnu packages commencement)} module, and are
17696 implicitly used by any package that uses @code{gnu-build-system}
17697 (@pxref{Build Systems, @code{gnu-build-system}}).
17700 @unnumberedsubsec Building the Bootstrap Binaries
17702 @cindex bootstrap binaries
17703 Because the final tool chain does not depend on the bootstrap binaries,
17704 those rarely need to be updated. Nevertheless, it is useful to have an
17705 automated way to produce them, should an update occur, and this is what
17706 the @code{(gnu packages make-bootstrap)} module provides.
17708 The following command builds the tarballs containing the bootstrap
17709 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
17710 of Coreutils and other basic command-line tools):
17713 guix build bootstrap-tarballs
17716 The generated tarballs are those that should be referred to in the
17717 @code{(gnu packages bootstrap)} module mentioned at the beginning of
17720 Still here? Then perhaps by now you've started to wonder: when do we
17721 reach a fixed point? That is an interesting question! The answer is
17722 unknown, but if you would like to investigate further (and have
17723 significant computational and storage resources to do so), then let us
17727 @section Porting to a New Platform
17729 As discussed above, the GNU distribution is self-contained, and
17730 self-containment is achieved by relying on pre-built ``bootstrap
17731 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
17732 operating system kernel, CPU architecture, and application binary
17733 interface (ABI). Thus, to port the distribution to a platform that is
17734 not yet supported, one must build those bootstrap binaries, and update
17735 the @code{(gnu packages bootstrap)} module to use them on that platform.
17737 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
17738 When everything goes well, and assuming the GNU tool chain supports the
17739 target platform, this can be as simple as running a command like this
17743 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
17746 For this to work, the @code{glibc-dynamic-linker} procedure in
17747 @code{(gnu packages bootstrap)} must be augmented to return the right
17748 file name for libc's dynamic linker on that platform; likewise,
17749 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
17750 taught about the new platform.
17752 Once these are built, the @code{(gnu packages bootstrap)} module needs
17753 to be updated to refer to these binaries on the target platform. That
17754 is, the hashes and URLs of the bootstrap tarballs for the new platform
17755 must be added alongside those of the currently supported platforms. The
17756 bootstrap Guile tarball is treated specially: it is expected to be
17757 available locally, and @file{gnu/local.mk} has rules do download it for
17758 the supported architectures; a rule for the new platform must be added
17761 In practice, there may be some complications. First, it may be that the
17762 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
17763 above) is not recognized by all the GNU tools. Typically, glibc
17764 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
17765 configure flag (see @code{gcc.scm} for examples of how to handle this).
17766 Second, some of the required packages could fail to build for that
17767 platform. Lastly, the generated binaries could be broken for some
17770 @c *********************************************************************
17771 @include contributing.texi
17773 @c *********************************************************************
17774 @node Acknowledgments
17775 @chapter Acknowledgments
17777 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
17778 which was designed and
17779 implemented by Eelco Dolstra, with contributions from other people (see
17780 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
17781 management, and promoted unprecedented features, such as transactional
17782 package upgrades and rollbacks, per-user profiles, and referentially
17783 transparent build processes. Without this work, Guix would not exist.
17785 The Nix-based software distributions, Nixpkgs and NixOS, have also been
17786 an inspiration for Guix.
17788 GNU@tie{}Guix itself is a collective work with contributions from a
17789 number of people. See the @file{AUTHORS} file in Guix for more
17790 information on these fine people. The @file{THANKS} file lists people
17791 who have helped by reporting bugs, taking care of the infrastructure,
17792 providing artwork and themes, making suggestions, and more---thank you!
17795 @c *********************************************************************
17796 @node GNU Free Documentation License
17797 @appendix GNU Free Documentation License
17798 @cindex license, GNU Free Documentation License
17799 @include fdl-1.3.texi
17801 @c *********************************************************************
17802 @node Concept Index
17803 @unnumbered Concept Index
17806 @node Programming Index
17807 @unnumbered Programming Index
17808 @syncodeindex tp fn
17809 @syncodeindex vr fn
17814 @c Local Variables:
17815 @c ispell-local-dictionary: "american";