6 @documentencoding UTF-8
7 @settitle GNU Guix Reference Manual
12 @c Identifier of the OpenPGP key used to sign tarballs and such.
13 @set OPENPGP-SIGNING-KEY-ID BCA689B636553801C3C62150197A5888235FACAC
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 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
35 Permission is granted to copy, distribute and/or modify this document
36 under the terms of the GNU Free Documentation License, Version 1.3 or
37 any later version published by the Free Software Foundation; with no
38 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
39 copy of the license is included in the section entitled ``GNU Free
40 Documentation License''.
43 @dircategory System administration
45 * Guix: (guix). Manage installed software and system configuration.
46 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
47 * guix build: (guix)Invoking guix build. Building packages.
48 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
49 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
50 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
53 @dircategory Software development
55 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
59 @title GNU Guix Reference Manual
60 @subtitle Using the GNU Guix Functional Package Manager
61 @author The GNU Guix Developers
64 @vskip 0pt plus 1filll
65 Edition @value{EDITION} @*
73 @c *********************************************************************
77 This document describes GNU Guix version @value{VERSION}, a functional
78 package management tool written for the GNU system.
81 * Introduction:: What is Guix about?
82 * Installation:: Installing Guix.
83 * Package Management:: Package installation, upgrade, etc.
84 * Programming Interface:: Using Guix in Scheme.
85 * Utilities:: Package management commands.
86 * GNU Distribution:: Software for your friendly GNU system.
87 * Contributing:: Your help needed!
89 * Acknowledgments:: Thanks!
90 * GNU Free Documentation License:: The license of this manual.
91 * Concept Index:: Concepts.
92 * Programming Index:: Data types, functions, and variables.
95 --- The Detailed Node Listing ---
99 * Binary Installation:: Getting Guix running in no time!
100 * Requirements:: Software needed to build and run Guix.
101 * Running the Test Suite:: Testing Guix.
102 * Setting Up the Daemon:: Preparing the build daemon's environment.
103 * Invoking guix-daemon:: Running the build daemon.
104 * Application Setup:: Application-specific setup.
106 Setting Up the Daemon
108 * Build Environment Setup:: Preparing the isolated build environment.
109 * Daemon Offload Setup:: Offloading builds to remote machines.
113 * Features:: How Guix will make your life brighter.
114 * Invoking guix package:: Package installation, removal, etc.
115 * Substitutes:: Downloading pre-built binaries.
116 * Packages with Multiple Outputs:: Single source package, multiple outputs.
117 * Invoking guix gc:: Running the garbage collector.
118 * Invoking guix pull:: Fetching the latest Guix and distribution.
119 * Invoking guix archive:: Exporting and importing store files.
121 Programming Interface
123 * Defining Packages:: Defining new packages.
124 * Build Systems:: Specifying how packages are built.
125 * The Store:: Manipulating the package store.
126 * Derivations:: Low-level interface to package derivations.
127 * The Store Monad:: Purely functional interface to the store.
128 * G-Expressions:: Manipulating build expressions.
132 * package Reference:: The package data type.
133 * origin Reference:: The origin data type.
137 * Invoking guix build:: Building packages from the command line.
138 * Invoking guix edit:: Editing package definitions.
139 * Invoking guix download:: Downloading a file and printing its hash.
140 * Invoking guix hash:: Computing the cryptographic hash of a file.
141 * Invoking guix import:: Importing package definitions.
142 * Invoking guix refresh:: Updating package definitions.
143 * Invoking guix lint:: Finding errors in package definitions.
144 * Invoking guix size:: Profiling disk usage.
145 * Invoking guix graph:: Visualizing the graph of packages.
146 * Invoking guix environment:: Setting up development environments.
147 * Invoking guix publish:: Sharing substitutes.
148 * Invoking guix challenge:: Challenging substitute servers.
149 * Invoking guix copy:: Copying to and from a remote store.
150 * Invoking guix container:: Process isolation.
152 Invoking @command{guix build}
154 * Common Build Options:: Build options for most commands.
155 * Package Transformation Options:: Creating variants of packages.
156 * Additional Build Options:: Options specific to 'guix build'.
160 * System Installation:: Installing the whole operating system.
161 * System Configuration:: Configuring the operating system.
162 * Installing Debugging Files:: Feeding the debugger.
163 * Security Updates:: Deploying security fixes quickly.
164 * Package Modules:: Packages from the programmer's viewpoint.
165 * Packaging Guidelines:: Growing the distribution.
166 * Bootstrapping:: GNU/Linux built from scratch.
167 * Porting:: Targeting another platform or kernel.
171 * Limitations:: What you can expect.
172 * Hardware Considerations:: Supported hardware.
173 * USB Stick Installation:: Preparing the installation medium.
174 * Preparing for Installation:: Networking, partitioning, etc.
175 * Proceeding with the Installation:: The real thing.
176 * Installing GuixSD in a VM:: GuixSD playground.
177 * Building the Installation Image:: How this comes to be.
181 * Using the Configuration System:: Customizing your GNU system.
182 * operating-system Reference:: Detail of operating-system declarations.
183 * File Systems:: Configuring file system mounts.
184 * Mapped Devices:: Block device extra processing.
185 * User Accounts:: Specifying user accounts.
186 * Locales:: Language and cultural convention settings.
187 * Services:: Specifying system services.
188 * Setuid Programs:: Programs running with root privileges.
189 * X.509 Certificates:: Authenticating HTTPS servers.
190 * Name Service Switch:: Configuring libc's name service switch.
191 * Initial RAM Disk:: Linux-Libre bootstrapping.
192 * GRUB Configuration:: Configuring the boot loader.
193 * Invoking guix system:: Instantiating a system configuration.
194 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
195 * Defining Services:: Adding new service definitions.
199 * Base Services:: Essential system services.
200 * Scheduled Job Execution:: The mcron service.
201 * Log Rotation:: The rottlog service.
202 * Networking Services:: Network setup, SSH daemon, etc.
203 * X Window:: Graphical display.
204 * Printing Services:: Local and remote printer support.
205 * Desktop Services:: D-Bus and desktop services.
206 * Database Services:: SQL databases.
207 * Mail Services:: IMAP, POP3, SMTP, and all that.
208 * Messaging Services:: Messaging services.
209 * Kerberos Services:: Kerberos services.
210 * Web Services:: Web servers.
211 * VPN Services:: VPN daemons.
212 * Network File System:: NFS related services.
213 * Continuous Integration:: The Cuirass service.
214 * Miscellaneous Services:: Other services.
218 * Service Composition:: The model for composing services.
219 * Service Types and Services:: Types and services.
220 * Service Reference:: API reference.
221 * Shepherd Services:: A particular type of service.
225 * Software Freedom:: What may go into the distribution.
226 * Package Naming:: What's in a name?
227 * Version Numbers:: When the name is not enough.
228 * Synopses and Descriptions:: Helping users find the right package.
229 * Python Modules:: Taming the snake.
230 * Perl Modules:: Little pearls.
231 * Java Packages:: Coffee break.
232 * Fonts:: Fond of fonts.
236 * Building from Git:: The latest and greatest.
237 * Running Guix Before It Is Installed:: Hacker tricks.
238 * The Perfect Setup:: The right tools.
239 * Coding Style:: Hygiene of the contributor.
240 * Submitting Patches:: Share your work.
244 * Programming Paradigm:: How to compose your elements.
245 * Modules:: Where to store your code?
246 * Data Types and Pattern Matching:: Implementing data structures.
247 * Formatting Code:: Writing conventions.
252 @c *********************************************************************
254 @chapter Introduction
257 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
258 using the international phonetic alphabet (IPA).} is a package
259 management tool for the GNU system. Guix makes it easy for unprivileged
260 users to install, upgrade, or remove packages, to roll back to a
261 previous package set, to build packages from source, and generally
262 assists with the creation and maintenance of software environments.
264 @cindex user interfaces
265 Guix provides a command-line package management interface
266 (@pxref{Invoking guix package}), a set of command-line utilities
267 (@pxref{Utilities}), as well as Scheme programming interfaces
268 (@pxref{Programming Interface}).
270 Its @dfn{build daemon} is responsible for building packages on behalf of
271 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
272 binaries from authorized sources (@pxref{Substitutes}).
274 @cindex extensibility of the distribution
275 @cindex customization, of packages
276 Guix includes package definitions for many GNU and non-GNU packages, all
277 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
278 user's computing freedom}. It is @emph{extensible}: users can write
279 their own package definitions (@pxref{Defining Packages}) and make them
280 available as independent package modules (@pxref{Package Modules}). It
281 is also @emph{customizable}: users can @emph{derive} specialized package
282 definitions from existing ones, including from the command line
283 (@pxref{Package Transformation Options}).
285 @cindex Guix System Distribution
287 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
288 where it complements the available tools without interference
289 (@pxref{Installation}), or you can use it as part of the standalone
290 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
291 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
292 system configuration and Guix takes care of instantiating the
293 configuration in a transactional, reproducible, and stateless fashion
294 (@pxref{System Configuration}).
296 @cindex functional package management
297 Under the hood, Guix implements the @dfn{functional package management}
298 discipline pioneered by Nix (@pxref{Acknowledgments}).
299 In Guix, the package build and installation process is seen
300 as a @emph{function}, in the mathematical sense. That function takes inputs,
301 such as build scripts, a compiler, and libraries, and
302 returns an installed package. As a pure function, its result depends
303 solely on its inputs---for instance, it cannot refer to software or
304 scripts that were not explicitly passed as inputs. A build function
305 always produces the same result when passed a given set of inputs. It
306 cannot alter the environment of the running system in
307 any way; for instance, it cannot create, modify, or delete files outside
308 of its build and installation directories. This is achieved by running
309 build processes in isolated environments (or @dfn{containers}), where only their
310 explicit inputs are visible.
313 The result of package build functions is @dfn{cached} in the file
314 system, in a special directory called @dfn{the store} (@pxref{The
315 Store}). Each package is installed in a directory of its own in the
316 store---by default under @file{/gnu/store}. The directory name contains
317 a hash of all the inputs used to build that package; thus, changing an
318 input yields a different directory name.
320 This approach is the foundation for the salient features of Guix: support
321 for transactional package upgrade and rollback, per-user installation, and
322 garbage collection of packages (@pxref{Features}).
325 @c *********************************************************************
327 @chapter Installation
329 @cindex installing Guix
330 GNU Guix is available for download from its website at
331 @url{http://www.gnu.org/software/guix/}. This section describes the
332 software requirements of Guix, as well as how to install it and get
335 Note that this section is concerned with the installation of the package
336 manager, which can be done on top of a running GNU/Linux system. If,
337 instead, you want to install the complete GNU operating system,
338 @pxref{System Installation}.
340 @cindex foreign distro
341 When installed on a running GNU/Linux system---thereafter called a
342 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
343 without interference. Its data lives exclusively in two directories,
344 usually @file{/gnu/store} and @file{/var/guix}; other files on your
345 system, such as @file{/etc}, are left untouched.
347 Once installed, Guix can be updated by running @command{guix pull}
348 (@pxref{Invoking guix pull}).
351 * Binary Installation:: Getting Guix running in no time!
352 * Requirements:: Software needed to build and run Guix.
353 * Running the Test Suite:: Testing Guix.
354 * Setting Up the Daemon:: Preparing the build daemon's environment.
355 * Invoking guix-daemon:: Running the build daemon.
356 * Application Setup:: Application-specific setup.
359 @node Binary Installation
360 @section Binary Installation
362 @cindex installing Guix from binaries
363 This section describes how to install Guix on an arbitrary system from a
364 self-contained tarball providing binaries for Guix and for all its
365 dependencies. This is often quicker than installing from source, which
366 is described in the next sections. The only requirement is to have
369 Installing goes along these lines:
373 @cindex downloading Guix binary
374 Download the binary tarball from
375 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
376 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
377 already running the kernel Linux, and so on.
379 @c The following is somewhat duplicated in ``System Installation''.
380 Make sure to download the associated @file{.sig} file and to verify the
381 authenticity of the tarball against it, along these lines:
384 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
385 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
388 If that command fails because you do not have the required public key,
389 then run this command to import it:
392 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
396 and rerun the @code{gpg --verify} command.
397 @c end authentication part
404 # tar --warning=no-timestamp -xf \
405 guix-binary-@value{VERSION}.@var{system}.tar.xz
406 # mv var/guix /var/ && mv gnu /
409 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
410 The latter contains a ready-to-use profile for @code{root} (see next
413 Do @emph{not} unpack the tarball on a working Guix system since that
414 would overwrite its own essential files.
416 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
417 not emit warnings about ``implausibly old time stamps'' (such
418 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
420 They stem from the fact that all the
421 files in the archive have their modification time set to zero (which
422 means January 1st, 1970.) This is done on purpose to make sure the
423 archive content is independent of its creation time, thus making it
427 Make @code{root}'s profile available under @file{~/.guix-profile}:
430 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
435 Create the group and user accounts for build users as explained below
436 (@pxref{Build Environment Setup}).
439 Run the daemon, and set it to automatically start on boot.
441 If your host distro uses the systemd init system, this can be achieved
445 # ln -s ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
447 # systemctl start guix-daemon && systemctl enable guix-daemon
450 If your host distro uses the Upstart init system:
453 # ln -s ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
457 Otherwise, you can still start the daemon manually with:
460 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
464 Make the @command{guix} command available to other users on the machine,
468 # mkdir -p /usr/local/bin
470 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
473 It is also a good idea to make the Info version of this manual available
477 # mkdir -p /usr/local/share/info
478 # cd /usr/local/share/info
479 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
483 That way, assuming @file{/usr/local/share/info} is in the search path,
484 running @command{info guix} will open this manual (@pxref{Other Info
485 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
489 @cindex substitutes, authorization thereof
490 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
491 (@pxref{Substitutes}), authorize them:
494 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
498 This completes root-level install of Guix. Each user will need to
499 perform additional steps to make their Guix environment ready for use,
500 @pxref{Application Setup}.
502 You can confirm that Guix is working by installing a sample package into
506 # guix package -i hello
509 The @code{guix} package must remain available in @code{root}'s profile,
510 or it would become subject to garbage collection---in which case you
511 would find yourself badly handicapped by the lack of the @command{guix}
512 command. In other words, do not remove @code{guix} by running
513 @code{guix package -r guix}.
515 The binary installation tarball can be (re)produced and verified simply
516 by running the following command in the Guix source tree:
519 make guix-binary.@var{system}.tar.xz
524 @section Requirements
526 This section lists requirements when building Guix from source. The
527 build procedure for Guix is the same as for other GNU software, and is
528 not covered here. Please see the files @file{README} and @file{INSTALL}
529 in the Guix source tree for additional details.
531 GNU Guix depends on the following packages:
534 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.7 or later;
535 @item @url{http://gnupg.org/, GNU libgcrypt};
536 @item @url{http://www.gnu.org/software/make/, GNU Make}.
539 The following dependencies are optional:
543 Installing @uref{http://gnutls.org/, GnuTLS-Guile} will allow you to
544 access @code{https} URLs for substitutes, which is highly recommended
545 (@pxref{Substitutes}). It also allows you to access HTTPS URLs with the
546 @command{guix download} command (@pxref{Invoking guix download}), the
547 @command{guix import pypi} command, and the @command{guix import cpan}
548 command. @xref{Guile Preparations, how to install the GnuTLS bindings
549 for Guile,, gnutls-guile, GnuTLS-Guile}.
553 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
554 allow you to use the @command{guix import pypi} command (@pxref{Invoking
555 guix import}). It is of
556 interest primarily for developers and not for casual users.
559 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
560 Support for build offloading (@pxref{Daemon Offload Setup}) and
561 @command{guix copy} (@pxref{Invoking guix copy}) depends on
562 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
563 version 0.10.2 or later.
566 When @url{http://zlib.net, zlib} is available, @command{guix publish}
567 can compress build byproducts (@pxref{Invoking guix publish}).
570 Unless @code{--disable-daemon} was passed to @command{configure}, the
571 following packages are also needed:
574 @item @url{http://sqlite.org, SQLite 3};
575 @item @url{http://www.bzip.org, libbz2};
576 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
580 @cindex state directory
581 When configuring Guix on a system that already has a Guix installation,
582 be sure to specify the same state directory as the existing installation
583 using the @code{--localstatedir} option of the @command{configure}
584 script (@pxref{Directory Variables, @code{localstatedir},, standards,
585 GNU Coding Standards}). The @command{configure} script protects against
586 unintended misconfiguration of @var{localstatedir} so you do not
587 inadvertently corrupt your store (@pxref{The Store}).
589 @cindex Nix, compatibility
590 When a working installation of @url{http://nixos.org/nix/, the Nix package
591 manager} is available, you
592 can instead configure Guix with @code{--disable-daemon}. In that case,
593 Nix replaces the three dependencies above.
595 Guix is compatible with Nix, so it is possible to share the same store
596 between both. To do so, you must pass @command{configure} not only the
597 same @code{--with-store-dir} value, but also the same
598 @code{--localstatedir} value. The latter is essential because it
599 specifies where the database that stores metadata about the store is
600 located, among other things. The default values for Nix are
601 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
602 Note that @code{--disable-daemon} is not required if
603 your goal is to share the store with Nix.
605 @node Running the Test Suite
606 @section Running the Test Suite
609 After a successful @command{configure} and @code{make} run, it is a good
610 idea to run the test suite. It can help catch issues with the setup or
611 environment, or bugs in Guix itself---and really, reporting test
612 failures is a good way to help improve the software. To run the test
619 Test cases can run in parallel: you can use the @code{-j} option of
620 GNU@tie{}make to speed things up. The first run may take a few minutes
621 on a recent machine; subsequent runs will be faster because the store
622 that is created for test purposes will already have various things in
625 It is also possible to run a subset of the tests by defining the
626 @code{TESTS} makefile variable as in this example:
629 make check TESTS="tests/store.scm tests/cpio.scm"
632 By default, tests results are displayed at a file level. In order to
633 see the details of every individual test cases, it is possible to define
634 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
637 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
640 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
641 @file{test-suite.log} file. Please specify the Guix version being used
642 as well as version numbers of the dependencies (@pxref{Requirements}) in
645 Guix also comes with a whole-system test suite that tests complete
646 GuixSD operating system instances. It can only run on systems where
647 Guix is already installed, using:
654 or, again, by defining @code{TESTS} to select a subset of tests to run:
657 make check-system TESTS="basic mcron"
660 These system tests are defined in the @code{(gnu tests @dots{})}
661 modules. They work by running the operating systems under test with
662 lightweight instrumentation in a virtual machine (VM). They can be
663 computationally intensive or rather cheap, depending on whether
664 substitutes are available for their dependencies (@pxref{Substitutes}).
665 Some of them require a lot of storage space to hold VM images.
667 Again in case of test failures, please send @email{bug-guix@@gnu.org}
670 @node Setting Up the Daemon
671 @section Setting Up the Daemon
674 Operations such as building a package or running the garbage collector
675 are all performed by a specialized process, the @dfn{build daemon}, on
676 behalf of clients. Only the daemon may access the store and its
677 associated database. Thus, any operation that manipulates the store
678 goes through the daemon. For instance, command-line tools such as
679 @command{guix package} and @command{guix build} communicate with the
680 daemon (@i{via} remote procedure calls) to instruct it what to do.
682 The following sections explain how to prepare the build daemon's
683 environment. See also @ref{Substitutes}, for information on how to allow
684 the daemon to download pre-built binaries.
687 * Build Environment Setup:: Preparing the isolated build environment.
688 * Daemon Offload Setup:: Offloading builds to remote machines.
691 @node Build Environment Setup
692 @subsection Build Environment Setup
694 @cindex build environment
695 In a standard multi-user setup, Guix and its daemon---the
696 @command{guix-daemon} program---are installed by the system
697 administrator; @file{/gnu/store} is owned by @code{root} and
698 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
699 Guix tools to build packages or otherwise access the store, and the
700 daemon will do it on their behalf, ensuring that the store is kept in a
701 consistent state, and allowing built packages to be shared among users.
704 When @command{guix-daemon} runs as @code{root}, you may not want package
705 build processes themselves to run as @code{root} too, for obvious
706 security reasons. To avoid that, a special pool of @dfn{build users}
707 should be created for use by build processes started by the daemon.
708 These build users need not have a shell and a home directory: they will
709 just be used when the daemon drops @code{root} privileges in build
710 processes. Having several such users allows the daemon to launch
711 distinct build processes under separate UIDs, which guarantees that they
712 do not interfere with each other---an essential feature since builds are
713 regarded as pure functions (@pxref{Introduction}).
715 On a GNU/Linux system, a build user pool may be created like this (using
716 Bash syntax and the @code{shadow} commands):
718 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
719 @c for why `-G' is needed.
721 # groupadd --system guixbuild
722 # for i in `seq -w 1 10`;
724 useradd -g guixbuild -G guixbuild \
725 -d /var/empty -s `which nologin` \
726 -c "Guix build user $i" --system \
732 The number of build users determines how many build jobs may run in
733 parallel, as specified by the @option{--max-jobs} option
734 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
735 @command{guix system vm} and related commands, you may need to add the
736 build users to the @code{kvm} group so they can access @file{/dev/kvm},
737 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
738 (@pxref{Invoking guix system}).
740 The @code{guix-daemon} program may then be run as @code{root} with the
741 following command@footnote{If your machine uses the systemd init system,
742 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
743 file in @file{/etc/systemd/system} will ensure that
744 @command{guix-daemon} is automatically started. Similarly, if your
745 machine uses the Upstart init system, drop the
746 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
747 file in @file{/etc/init}.}:
750 # guix-daemon --build-users-group=guixbuild
755 This way, the daemon starts build processes in a chroot, under one of
756 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
757 environment contains nothing but:
759 @c Keep this list in sync with libstore/build.cc! -----------------------
762 a minimal @code{/dev} directory, created mostly independently from the
763 host @code{/dev}@footnote{``Mostly'', because while the set of files
764 that appear in the chroot's @code{/dev} is fixed, most of these files
765 can only be created if the host has them.};
768 the @code{/proc} directory; it only shows the processes of the container
769 since a separate PID name space is used;
772 @file{/etc/passwd} with an entry for the current user and an entry for
776 @file{/etc/group} with an entry for the user's group;
779 @file{/etc/hosts} with an entry that maps @code{localhost} to
783 a writable @file{/tmp} directory.
786 You can influence the directory where the daemon stores build trees
787 @i{via} the @code{TMPDIR} environment variable. However, the build tree
788 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
789 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
790 This way, the value of @code{TMPDIR} does not leak inside build
791 environments, which avoids discrepancies in cases where build processes
792 capture the name of their build tree.
795 The daemon also honors the @code{http_proxy} environment variable for
796 HTTP downloads it performs, be it for fixed-output derivations
797 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
799 If you are installing Guix as an unprivileged user, it is still possible
800 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
801 However, build processes will not be isolated from one another, and not
802 from the rest of the system. Thus, build processes may interfere with
803 each other, and may access programs, libraries, and other files
804 available on the system---making it much harder to view them as
805 @emph{pure} functions.
808 @node Daemon Offload Setup
809 @subsection Using the Offload Facility
813 When desired, the build daemon can @dfn{offload} derivation builds to
814 other machines running Guix, using the @code{offload} @dfn{build
815 hook}@footnote{This feature is available only when
816 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
818 feature is enabled, a list of user-specified build machines is read from
819 @file{/etc/guix/machines.scm}; every time a build is requested, for
820 instance via @code{guix build}, the daemon attempts to offload it to one
821 of the machines that satisfy the constraints of the derivation, in
822 particular its system type---e.g., @file{x86_64-linux}. Missing
823 prerequisites for the build are copied over SSH to the target machine,
824 which then proceeds with the build; upon success the output(s) of the
825 build are copied back to the initial machine.
827 The @file{/etc/guix/machines.scm} file typically looks like this:
831 (name "eightysix.example.org")
832 (system "x86_64-linux")
833 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
835 (speed 2.)) ;incredibly fast!
838 (name "meeps.example.org")
839 (system "mips64el-linux")
840 (host-key "ssh-rsa AAAAB3Nza@dots{}")
843 (string-append (getenv "HOME")
844 "/.ssh/identity-for-guix"))))
848 In the example above we specify a list of two build machines, one for
849 the @code{x86_64} architecture and one for the @code{mips64el}
852 In fact, this file is---not surprisingly!---a Scheme file that is
853 evaluated when the @code{offload} hook is started. Its return value
854 must be a list of @code{build-machine} objects. While this example
855 shows a fixed list of build machines, one could imagine, say, using
856 DNS-SD to return a list of potential build machines discovered in the
857 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
858 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
861 @deftp {Data Type} build-machine
862 This data type represents build machines to which the daemon may offload
863 builds. The important fields are:
868 The host name of the remote machine.
871 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
874 The user account to use when connecting to the remote machine over SSH.
875 Note that the SSH key pair must @emph{not} be passphrase-protected, to
876 allow non-interactive logins.
879 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
880 This is used to authenticate the machine when we connect to it. It is a
881 long string that looks like this:
884 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
887 If the machine is running the OpenSSH daemon, @command{sshd}, the host
888 key can be found in a file such as
889 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
891 If the machine is running the SSH daemon of GNU@tie{}lsh,
892 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
893 similar file. It can be converted to the OpenSSH format using
894 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
897 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
898 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
903 A number of optional fields may be specified:
907 @item @code{port} (default: @code{22})
908 Port number of SSH server on the machine.
910 @item @code{private-key} (default: @file{~/.ssh/id_rsa})
911 The SSH private key file to use when connecting to the machine, in
914 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
915 @itemx @code{compression-level} (default: @code{3})
916 The SSH-level compression methods and compression level requested.
918 Note that offloading relies on SSH compression to reduce bandwidth usage
919 when transferring files to and from build machines.
921 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
922 File name of the Unix-domain socket @command{guix-daemon} is listening
925 @item @code{parallel-builds} (default: @code{1})
926 The number of builds that may run in parallel on the machine.
928 @item @code{speed} (default: @code{1.0})
929 A ``relative speed factor''. The offload scheduler will tend to prefer
930 machines with a higher speed factor.
932 @item @code{features} (default: @code{'()})
933 A list of strings denoting specific features supported by the machine.
934 An example is @code{"kvm"} for machines that have the KVM Linux modules
935 and corresponding hardware support. Derivations can request features by
936 name, and they will be scheduled on matching build machines.
941 The @code{guile} command must be in the search path on the build
942 machines. In addition, the Guix modules must be in
943 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
944 this is the case by running:
947 ssh build-machine guile -c "'(use-modules (guix config))'"
950 There is one last thing to do once @file{machines.scm} is in place. As
951 explained above, when offloading, files are transferred back and forth
952 between the machine stores. For this to work, you first need to
953 generate a key pair on each machine to allow the daemon to export signed
954 archives of files from the store (@pxref{Invoking guix archive}):
957 # guix archive --generate-key
961 Each build machine must authorize the key of the master machine so that
962 it accepts store items it receives from the master:
965 # guix archive --authorize < master-public-key.txt
969 Likewise, the master machine must authorize the key of each build machine.
971 All the fuss with keys is here to express pairwise mutual trust
972 relations between the master and the build machines. Concretely, when
973 the master receives files from a build machine (and @i{vice versa}), its
974 build daemon can make sure they are genuine, have not been tampered
975 with, and that they are signed by an authorized key.
978 To test whether your setup is operational, run this command on the
985 This will attempt to connect to each of the build machines specified in
986 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
987 available on each machine, attempt to export to the machine and import
988 from it, and report any error in the process.
990 If you want to test a different machine file, just specify it on the
994 # guix offload test machines-qualif.scm
997 Last, you can test the subset of the machines whose name matches a
998 regular expression like this:
1001 # guix offload test machines.scm '\.gnu\.org$'
1004 @node Invoking guix-daemon
1005 @section Invoking @command{guix-daemon}
1007 The @command{guix-daemon} program implements all the functionality to
1008 access the store. This includes launching build processes, running the
1009 garbage collector, querying the availability of a build result, etc. It
1010 is normally run as @code{root} like this:
1013 # guix-daemon --build-users-group=guixbuild
1017 For details on how to set it up, @pxref{Setting Up the Daemon}.
1020 @cindex container, build environment
1021 @cindex build environment
1022 @cindex reproducible builds
1023 By default, @command{guix-daemon} launches build processes under
1024 different UIDs, taken from the build group specified with
1025 @code{--build-users-group}. In addition, each build process is run in a
1026 chroot environment that only contains the subset of the store that the
1027 build process depends on, as specified by its derivation
1028 (@pxref{Programming Interface, derivation}), plus a set of specific
1029 system directories. By default, the latter contains @file{/dev} and
1030 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1031 @dfn{container}: in addition to having its own file system tree, it has
1032 a separate mount name space, its own PID name space, network name space,
1033 etc. This helps achieve reproducible builds (@pxref{Features}).
1035 When the daemon performs a build on behalf of the user, it creates a
1036 build directory under @file{/tmp} or under the directory specified by
1037 its @code{TMPDIR} environment variable; this directory is shared with
1038 the container for the duration of the build. Be aware that using a
1039 directory other than @file{/tmp} can affect build results---for example,
1040 with a longer directory name, a build process that uses Unix-domain
1041 sockets might hit the name length limitation for @code{sun_path}, which
1042 it would otherwise not hit.
1044 The build directory is automatically deleted upon completion, unless the
1045 build failed and the client specified @option{--keep-failed}
1046 (@pxref{Invoking guix build, @option{--keep-failed}}).
1048 The following command-line options are supported:
1051 @item --build-users-group=@var{group}
1052 Take users from @var{group} to run build processes (@pxref{Setting Up
1053 the Daemon, build users}).
1055 @item --no-substitutes
1057 Do not use substitutes for build products. That is, always build things
1058 locally instead of allowing downloads of pre-built binaries
1059 (@pxref{Substitutes}).
1061 By default substitutes are used, unless the client---such as the
1062 @command{guix package} command---is explicitly invoked with
1063 @code{--no-substitutes}.
1065 When the daemon runs with @code{--no-substitutes}, clients can still
1066 explicitly enable substitution @i{via} the @code{set-build-options}
1067 remote procedure call (@pxref{The Store}).
1069 @item --substitute-urls=@var{urls}
1070 @anchor{daemon-substitute-urls}
1071 Consider @var{urls} the default whitespace-separated list of substitute
1072 source URLs. When this option is omitted,
1073 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1074 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1076 This means that substitutes may be downloaded from @var{urls}, as long
1077 as they are signed by a trusted signature (@pxref{Substitutes}).
1080 @item --no-build-hook
1081 Do not use the @dfn{build hook}.
1083 The build hook is a helper program that the daemon can start and to
1084 which it submits build requests. This mechanism is used to offload
1085 builds to other machines (@pxref{Daemon Offload Setup}).
1087 @item --cache-failures
1088 Cache build failures. By default, only successful builds are cached.
1090 When this option is used, @command{guix gc --list-failures} can be used
1091 to query the set of store items marked as failed; @command{guix gc
1092 --clear-failures} removes store items from the set of cached failures.
1093 @xref{Invoking guix gc}.
1095 @item --cores=@var{n}
1097 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1100 The default value is @code{0}, but it may be overridden by clients, such
1101 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1104 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1105 in the build process, which can then use it to exploit internal
1106 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1108 @item --max-jobs=@var{n}
1110 Allow at most @var{n} build jobs in parallel. The default value is
1111 @code{1}. Setting it to @code{0} means that no builds will be performed
1112 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1113 Setup}), or simply fail.
1115 @item --rounds=@var{N}
1116 Build each derivation @var{n} times in a row, and raise an error if
1117 consecutive build results are not bit-for-bit identical. Note that this
1118 setting can be overridden by clients such as @command{guix build}
1119 (@pxref{Invoking guix build}).
1121 When used in conjunction with @option{--keep-failed}, the differing
1122 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1123 This makes it easy to look for differences between the two results.
1126 Produce debugging output.
1128 This is useful to debug daemon start-up issues, but then it may be
1129 overridden by clients, for example the @code{--verbosity} option of
1130 @command{guix build} (@pxref{Invoking guix build}).
1132 @item --chroot-directory=@var{dir}
1133 Add @var{dir} to the build chroot.
1135 Doing this may change the result of build processes---for instance if
1136 they use optional dependencies found in @var{dir} when it is available,
1137 and not otherwise. For that reason, it is not recommended to do so.
1138 Instead, make sure that each derivation declares all the inputs that it
1141 @item --disable-chroot
1142 Disable chroot builds.
1144 Using this option is not recommended since, again, it would allow build
1145 processes to gain access to undeclared dependencies. It is necessary,
1146 though, when @command{guix-daemon} is running under an unprivileged user
1149 @item --disable-log-compression
1150 Disable compression of the build logs.
1152 Unless @code{--lose-logs} is used, all the build logs are kept in the
1153 @var{localstatedir}. To save space, the daemon automatically compresses
1154 them with bzip2 by default. This option disables that.
1156 @item --disable-deduplication
1157 @cindex deduplication
1158 Disable automatic file ``deduplication'' in the store.
1160 By default, files added to the store are automatically ``deduplicated'':
1161 if a newly added file is identical to another one found in the store,
1162 the daemon makes the new file a hard link to the other file. This can
1163 noticeably reduce disk usage, at the expense of slightly increased
1164 input/output load at the end of a build process. This option disables
1167 @item --gc-keep-outputs[=yes|no]
1168 Tell whether the garbage collector (GC) must keep outputs of live
1171 When set to ``yes'', the GC will keep the outputs of any live derivation
1172 available in the store---the @code{.drv} files. The default is ``no'',
1173 meaning that derivation outputs are kept only if they are GC roots.
1175 @item --gc-keep-derivations[=yes|no]
1176 Tell whether the garbage collector (GC) must keep derivations
1177 corresponding to live outputs.
1179 When set to ``yes'', as is the case by default, the GC keeps
1180 derivations---i.e., @code{.drv} files---as long as at least one of their
1181 outputs is live. This allows users to keep track of the origins of
1182 items in their store. Setting it to ``no'' saves a bit of disk space.
1184 Note that when both @code{--gc-keep-derivations} and
1185 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1186 prerequisites (the sources, compiler, libraries, and other build-time
1187 tools) of live objects in the store, regardless of whether these
1188 prerequisites are live. This is convenient for developers since it
1189 saves rebuilds or downloads.
1191 @item --impersonate-linux-2.6
1192 On Linux-based systems, impersonate Linux 2.6. This means that the
1193 kernel's @code{uname} system call will report 2.6 as the release number.
1195 This might be helpful to build programs that (usually wrongfully) depend
1196 on the kernel version number.
1199 Do not keep build logs. By default they are kept under
1200 @code{@var{localstatedir}/guix/log}.
1202 @item --system=@var{system}
1203 Assume @var{system} as the current system type. By default it is the
1204 architecture/kernel pair found at configure time, such as
1205 @code{x86_64-linux}.
1207 @item --listen=@var{socket}
1208 Listen for connections on @var{socket}, the file name of a Unix-domain
1209 socket. The default socket is
1210 @file{@var{localstatedir}/daemon-socket/socket}. This option is only
1211 useful in exceptional circumstances, such as if you need to run several
1212 daemons on the same machine.
1216 @node Application Setup
1217 @section Application Setup
1219 @cindex foreign distro
1220 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1221 so-called @dfn{foreign distro}---a few additional steps are needed to
1222 get everything in place. Here are some of them.
1226 @anchor{locales-and-locpath}
1227 @cindex locales, when not on GuixSD
1229 @vindex GUIX_LOCPATH
1230 Packages installed @i{via} Guix will not use the locale data of the
1231 host system. Instead, you must first install one of the locale packages
1232 available with Guix and then define the @code{GUIX_LOCPATH} environment
1236 $ guix package -i glibc-locales
1237 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1240 Note that the @code{glibc-locales} package contains data for all the
1241 locales supported by the GNU@tie{}libc and weighs in at around
1242 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1243 limited to a few UTF-8 locales.
1245 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1246 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1247 Manual}). There are two important differences though:
1251 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1252 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1253 to make sure the programs of the foreign distro will not end up loading
1254 incompatible locale data.
1257 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1258 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1259 should your Guix profile contain a mixture of programs linked against
1260 different libc version, each libc version will only try to load locale
1261 data in the right format.
1264 This is important because the locale data format used by different libc
1265 versions may be incompatible.
1267 @subsection Name Service Switch
1269 @cindex name service switch, glibc
1270 @cindex NSS (name service switch), glibc
1271 @cindex nscd (name service caching daemon)
1272 @cindex name service caching daemon (nscd)
1273 When using Guix on a foreign distro, we @emph{strongly recommend} that
1274 the system run the GNU C library's @dfn{name service cache daemon},
1275 @command{nscd}, which should be listening on the
1276 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1277 installed with Guix may fail to look up host names or user accounts, or
1278 may even crash. The next paragraphs explain why.
1280 @cindex @file{nsswitch.conf}
1281 The GNU C library implements a @dfn{name service switch} (NSS), which is
1282 an extensible mechanism for ``name lookups'' in general: host name
1283 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1284 The GNU C Library Reference Manual}).
1286 @cindex Network information service (NIS)
1287 @cindex NIS (Network information service)
1288 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1289 lookup implementations: for example, the @code{nss-mdns} plugin allow
1290 resolution of @code{.local} host names, the @code{nis} plugin allows
1291 user account lookup using the Network information service (NIS), and so
1292 on. These extra ``lookup services'' are configured system-wide in
1293 @file{/etc/nsswitch.conf}, and all the programs running on the system
1294 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1297 When they perform a name lookup---for instance by calling the
1298 @code{getaddrinfo} function in C---applications first try to connect to
1299 the nscd; on success, nscd performs name lookups on their behalf. If
1300 the nscd is not running, then they perform the name lookup by
1301 themselves, by loading the name lookup services into their own address
1302 space and running it. These name lookup services---the
1303 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1304 the host system's C library, rather than from the C library the
1305 application is linked against (the C library coming from Guix).
1307 And this is where the problem is: if your application is linked against
1308 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1309 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1310 likely crash or have its name lookups fail unexpectedly.
1312 Running @command{nscd} on the system, among other advantages, eliminates
1313 this binary incompatibility problem because those @code{libnss_*.so}
1314 files are loaded in the @command{nscd} process, not in applications
1317 @subsection X11 Fonts
1320 The majority of graphical applications use Fontconfig to locate and
1321 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1322 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1323 by default. Thus, to allow graphical applications installed with Guix
1324 to display fonts, you have to install fonts with Guix as well.
1325 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1326 @code{font-gnu-freefont-ttf}.
1328 To display text written in Chinese languages, Japanese, or Korean in
1329 graphical applications, consider installing
1330 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1331 has multiple outputs, one per language family (@pxref{Packages with
1332 Multiple Outputs}). For instance, the following command installs fonts
1333 for Chinese languages:
1336 guix package -i font-adobe-source-han-sans:cn
1339 @cindex @code{xterm}
1340 Older programs such as @command{xterm} do not use Fontconfig and instead
1341 rely on server-side font rendering. Such programs require to specify a
1342 full name of a font using XLFD (X Logical Font Description), like this:
1345 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1348 To be able to use such full names for the TrueType fonts installed in
1349 your Guix profile, you need to extend the font path of the X server:
1352 xset +fp ~/.guix-profile/share/fonts/truetype
1355 @cindex @code{xlsfonts}
1356 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1357 to make sure your TrueType fonts are listed there.
1359 @subsection X.509 Certificates
1361 @cindex @code{nss-certs}
1362 The @code{nss-certs} package provides X.509 certificates, which allow
1363 programs to authenticate Web servers accessed over HTTPS.
1365 When using Guix on a foreign distro, you can install this package and
1366 define the relevant environment variables so that packages know where to
1367 look for certificates. @xref{X.509 Certificates}, for detailed
1370 @subsection Emacs Packages
1372 @cindex @code{emacs}
1373 When you install Emacs packages with Guix, the elisp files may be placed
1374 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1376 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1377 directory exists because potentially there may exist thousands of Emacs
1378 packages and storing all their files in a single directory may be not
1379 reliable (because of name conflicts). So we think using a separate
1380 directory for each package is a good idea. It is very similar to how
1381 the Emacs package system organizes the file structure (@pxref{Package
1382 Files,,, emacs, The GNU Emacs Manual}).
1384 By default, Emacs (installed with Guix) ``knows'' where these packages
1385 are placed, so you do not need to perform any configuration. If, for
1386 some reason, you want to avoid auto-loading Emacs packages installed
1387 with Guix, you can do so by running Emacs with @code{--no-site-file}
1388 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1392 @c *********************************************************************
1393 @node Package Management
1394 @chapter Package Management
1397 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1398 remove software packages, without having to know about their build
1399 procedures or dependencies. Guix also goes beyond this obvious set of
1402 This chapter describes the main features of Guix, as well as the package
1403 management tools it provides. Along with the command-line interface
1404 described below (@pxref{Invoking guix package, @code{guix package}}),
1405 you may also use Emacs Interface, after installing @code{emacs-guix}
1406 package (run @kbd{M-x guix-help} command to start with it):
1409 guix package -i emacs-guix
1413 * Features:: How Guix will make your life brighter.
1414 * Invoking guix package:: Package installation, removal, etc.
1415 * Substitutes:: Downloading pre-built binaries.
1416 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1417 * Invoking guix gc:: Running the garbage collector.
1418 * Invoking guix pull:: Fetching the latest Guix and distribution.
1419 * Invoking guix archive:: Exporting and importing store files.
1425 When using Guix, each package ends up in the @dfn{package store}, in its
1426 own directory---something that resembles
1427 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1429 Instead of referring to these directories, users have their own
1430 @dfn{profile}, which points to the packages that they actually want to
1431 use. These profiles are stored within each user's home directory, at
1432 @code{$HOME/.guix-profile}.
1434 For example, @code{alice} installs GCC 4.7.2. As a result,
1435 @file{/home/alice/.guix-profile/bin/gcc} points to
1436 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1437 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1438 simply continues to point to
1439 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1440 coexist on the same system without any interference.
1442 The @command{guix package} command is the central tool to manage
1443 packages (@pxref{Invoking guix package}). It operates on the per-user
1444 profiles, and can be used @emph{with normal user privileges}.
1446 @cindex transactions
1447 The command provides the obvious install, remove, and upgrade
1448 operations. Each invocation is actually a @emph{transaction}: either
1449 the specified operation succeeds, or nothing happens. Thus, if the
1450 @command{guix package} process is terminated during the transaction,
1451 or if a power outage occurs during the transaction, then the user's
1452 profile remains in its previous state, and remains usable.
1454 In addition, any package transaction may be @emph{rolled back}. So, if,
1455 for example, an upgrade installs a new version of a package that turns
1456 out to have a serious bug, users may roll back to the previous instance
1457 of their profile, which was known to work well. Similarly, the global
1458 system configuration on GuixSD is subject to
1459 transactional upgrades and roll-back
1460 (@pxref{Using the Configuration System}).
1462 All packages in the package store may be @emph{garbage-collected}.
1463 Guix can determine which packages are still referenced by user
1464 profiles, and remove those that are provably no longer referenced
1465 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1466 generations of their profile so that the packages they refer to can be
1469 @cindex reproducibility
1470 @cindex reproducible builds
1471 Finally, Guix takes a @dfn{purely functional} approach to package
1472 management, as described in the introduction (@pxref{Introduction}).
1473 Each @file{/gnu/store} package directory name contains a hash of all the
1474 inputs that were used to build that package---compiler, libraries, build
1475 scripts, etc. This direct correspondence allows users to make sure a
1476 given package installation matches the current state of their
1477 distribution. It also helps maximize @dfn{build reproducibility}:
1478 thanks to the isolated build environments that are used, a given build
1479 is likely to yield bit-identical files when performed on different
1480 machines (@pxref{Invoking guix-daemon, container}).
1483 This foundation allows Guix to support @dfn{transparent binary/source
1484 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1485 available from an external source---a @dfn{substitute}, Guix just
1486 downloads it and unpacks it;
1487 otherwise, it builds the package from source, locally
1488 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1489 reproducible, users do not have to trust servers that provide
1490 substitutes: they can force a local build and @emph{challenge} providers
1491 (@pxref{Invoking guix challenge}).
1493 Control over the build environment is a feature that is also useful for
1494 developers. The @command{guix environment} command allows developers of
1495 a package to quickly set up the right development environment for their
1496 package, without having to manually install the dependencies of the
1497 package into their profile (@pxref{Invoking guix environment}).
1499 @node Invoking guix package
1500 @section Invoking @command{guix package}
1502 @cindex installing packages
1503 @cindex removing packages
1504 @cindex package installation
1505 @cindex package removal
1506 The @command{guix package} command is the tool that allows users to
1507 install, upgrade, and remove packages, as well as rolling back to
1508 previous configurations. It operates only on the user's own profile,
1509 and works with normal user privileges (@pxref{Features}). Its syntax
1513 guix package @var{options}
1515 @cindex transactions
1516 Primarily, @var{options} specifies the operations to be performed during
1517 the transaction. Upon completion, a new profile is created, but
1518 previous @dfn{generations} of the profile remain available, should the user
1521 For example, to remove @code{lua} and install @code{guile} and
1522 @code{guile-cairo} in a single transaction:
1525 guix package -r lua -i guile guile-cairo
1528 @command{guix package} also supports a @dfn{declarative approach}
1529 whereby the user specifies the exact set of packages to be available and
1530 passes it @i{via} the @option{--manifest} option
1531 (@pxref{profile-manifest, @option{--manifest}}).
1534 For each user, a symlink to the user's default profile is automatically
1535 created in @file{$HOME/.guix-profile}. This symlink always points to the
1536 current generation of the user's default profile. Thus, users can add
1537 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1538 variable, and so on.
1539 @cindex search paths
1540 If you are not using the Guix System Distribution, consider adding the
1541 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1542 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1543 shells get all the right environment variable definitions:
1546 GUIX_PROFILE="$HOME/.guix-profile" \
1547 source "$HOME/.guix-profile/etc/profile"
1550 In a multi-user setup, user profiles are stored in a place registered as
1551 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1552 to (@pxref{Invoking guix gc}). That directory is normally
1553 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1554 @var{localstatedir} is the value passed to @code{configure} as
1555 @code{--localstatedir}, and @var{user} is the user name. The
1556 @file{per-user} directory is created when @command{guix-daemon} is
1557 started, and the @var{user} sub-directory is created by @command{guix
1560 The @var{options} can be among the following:
1564 @item --install=@var{package} @dots{}
1565 @itemx -i @var{package} @dots{}
1566 Install the specified @var{package}s.
1568 Each @var{package} may specify either a simple package name, such as
1569 @code{guile}, or a package name followed by an at-sign and version number,
1570 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1571 case, the newest version prefixed by @code{1.8} is selected.)
1573 If no version number is specified, the
1574 newest available version will be selected. In addition, @var{package}
1575 may contain a colon, followed by the name of one of the outputs of the
1576 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1577 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1578 name (and optionally version) are searched for among the GNU
1579 distribution modules (@pxref{Package Modules}).
1581 @cindex propagated inputs
1582 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1583 that automatically get installed along with the required package
1584 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1585 @code{package} objects}, for information about propagated inputs in
1586 package definitions).
1588 @anchor{package-cmd-propagated-inputs}
1589 An example is the GNU MPC library: its C header files refer to those of
1590 the GNU MPFR library, which in turn refer to those of the GMP library.
1591 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1592 in the profile; removing MPC also removes MPFR and GMP---unless they had
1593 also been explicitly installed by the user.
1595 Besides, packages sometimes rely on the definition of environment
1596 variables for their search paths (see explanation of
1597 @code{--search-paths} below). Any missing or possibly incorrect
1598 environment variable definitions are reported here.
1600 @item --install-from-expression=@var{exp}
1602 Install the package @var{exp} evaluates to.
1604 @var{exp} must be a Scheme expression that evaluates to a
1605 @code{<package>} object. This option is notably useful to disambiguate
1606 between same-named variants of a package, with expressions such as
1607 @code{(@@ (gnu packages base) guile-final)}.
1609 Note that this option installs the first output of the specified
1610 package, which may be insufficient when needing a specific output of a
1611 multiple-output package.
1613 @item --install-from-file=@var{file}
1614 @itemx -f @var{file}
1615 Install the package that the code within @var{file} evaluates to.
1617 As an example, @var{file} might contain a definition like this
1618 (@pxref{Defining Packages}):
1621 @verbatiminclude package-hello.scm
1624 Developers may find it useful to include such a @file{guix.scm} file
1625 in the root of their project source tree that can be used to test
1626 development snapshots and create reproducible development environments
1627 (@pxref{Invoking guix environment}).
1629 @item --remove=@var{package} @dots{}
1630 @itemx -r @var{package} @dots{}
1631 Remove the specified @var{package}s.
1633 As for @code{--install}, each @var{package} may specify a version number
1634 and/or output name in addition to the package name. For instance,
1635 @code{-r glibc:debug} would remove the @code{debug} output of
1638 @item --upgrade[=@var{regexp} @dots{}]
1639 @itemx -u [@var{regexp} @dots{}]
1640 @cindex upgrading packages
1641 Upgrade all the installed packages. If one or more @var{regexp}s are
1642 specified, upgrade only installed packages whose name matches a
1643 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1645 Note that this upgrades package to the latest version of packages found
1646 in the distribution currently installed. To update your distribution,
1647 you should regularly run @command{guix pull} (@pxref{Invoking guix
1650 @item --do-not-upgrade[=@var{regexp} @dots{}]
1651 When used together with the @code{--upgrade} option, do @emph{not}
1652 upgrade any packages whose name matches a @var{regexp}. For example, to
1653 upgrade all packages in the current profile except those containing the
1654 substring ``emacs'':
1657 $ guix package --upgrade . --do-not-upgrade emacs
1660 @item @anchor{profile-manifest}--manifest=@var{file}
1661 @itemx -m @var{file}
1662 @cindex profile declaration
1663 @cindex profile manifest
1664 Create a new generation of the profile from the manifest object
1665 returned by the Scheme code in @var{file}.
1667 This allows you to @emph{declare} the profile's contents rather than
1668 constructing it through a sequence of @code{--install} and similar
1669 commands. The advantage is that @var{file} can be put under version
1670 control, copied to different machines to reproduce the same profile, and
1673 @c FIXME: Add reference to (guix profile) documentation when available.
1674 @var{file} must return a @dfn{manifest} object, which is roughly a list
1677 @findex packages->manifest
1679 (use-package-modules guile emacs)
1684 ;; Use a specific package output.
1685 (list guile-2.0 "debug")))
1688 @findex specification->package+output
1689 In this example we have to know which modules define the @code{emacs}
1690 and @code{guile-2.0} variables to provide the right
1691 @code{use-package-modules} line, which can be cumbersome. We can
1692 instead provide regular package specifications and let
1693 @code{specification->package-output} look up the corresponding package
1698 (map (compose list specification->package+output)
1699 '("emacs" "guile@@2.0" "guile@@2.0:debug")))
1703 @cindex rolling back
1704 @cindex undoing transactions
1705 @cindex transactions, undoing
1706 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1707 the last transaction.
1709 When combined with options such as @code{--install}, roll back occurs
1710 before any other actions.
1712 When rolling back from the first generation that actually contains
1713 installed packages, the profile is made to point to the @dfn{zeroth
1714 generation}, which contains no files apart from its own metadata.
1716 After having rolled back, installing, removing, or upgrading packages
1717 overwrites previous future generations. Thus, the history of the
1718 generations in a profile is always linear.
1720 @item --switch-generation=@var{pattern}
1721 @itemx -S @var{pattern}
1723 Switch to a particular generation defined by @var{pattern}.
1725 @var{pattern} may be either a generation number or a number prefixed
1726 with ``+'' or ``-''. The latter means: move forward/backward by a
1727 specified number of generations. For example, if you want to return to
1728 the latest generation after @code{--roll-back}, use
1729 @code{--switch-generation=+1}.
1731 The difference between @code{--roll-back} and
1732 @code{--switch-generation=-1} is that @code{--switch-generation} will
1733 not make a zeroth generation, so if a specified generation does not
1734 exist, the current generation will not be changed.
1736 @item --search-paths[=@var{kind}]
1737 @cindex search paths
1738 Report environment variable definitions, in Bash syntax, that may be
1739 needed in order to use the set of installed packages. These environment
1740 variables are used to specify @dfn{search paths} for files used by some
1741 of the installed packages.
1743 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1744 environment variables to be defined so it can look for headers and
1745 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1746 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1747 library are installed in the profile, then @code{--search-paths} will
1748 suggest setting these variables to @code{@var{profile}/include} and
1749 @code{@var{profile}/lib}, respectively.
1751 The typical use case is to define these environment variables in the
1755 $ eval `guix package --search-paths`
1758 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1759 meaning that the returned environment variable definitions will either
1760 be exact settings, or prefixes or suffixes of the current value of these
1761 variables. When omitted, @var{kind} defaults to @code{exact}.
1763 This option can also be used to compute the @emph{combined} search paths
1764 of several profiles. Consider this example:
1767 $ guix package -p foo -i guile
1768 $ guix package -p bar -i guile-json
1769 $ guix package -p foo -p bar --search-paths
1772 The last command above reports about the @code{GUILE_LOAD_PATH}
1773 variable, even though, taken individually, neither @file{foo} nor
1774 @file{bar} would lead to that recommendation.
1777 @item --profile=@var{profile}
1778 @itemx -p @var{profile}
1779 Use @var{profile} instead of the user's default profile.
1782 Produce verbose output. In particular, emit the build log of the
1783 environment on the standard error port.
1786 Use the bootstrap Guile to build the profile. This option is only
1787 useful to distribution developers.
1791 In addition to these actions, @command{guix package} supports the
1792 following options to query the current state of a profile, or the
1793 availability of packages:
1797 @item --search=@var{regexp}
1798 @itemx -s @var{regexp}
1799 @cindex searching for packages
1800 List the available packages whose name, synopsis, or description matches
1801 @var{regexp}. Print all the metadata of matching packages in
1802 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1803 GNU recutils manual}).
1805 This allows specific fields to be extracted using the @command{recsel}
1806 command, for instance:
1809 $ guix package -s malloc | recsel -p name,version
1817 Similarly, to show the name of all the packages available under the
1818 terms of the GNU@tie{}LGPL version 3:
1821 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1828 It is also possible to refine search results using several @code{-s}
1829 flags. For example, the following command returns a list of board
1833 $ guix package -s '\<board\>' -s game | recsel -p name
1838 If we were to omit @code{-s game}, we would also get software packages
1839 that deal with printed circuit boards; removing the angle brackets
1840 around @code{board} would further add packages that have to do with
1843 And now for a more elaborate example. The following command searches
1844 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1845 libraries, and prints the name and synopsis of the matching packages:
1848 $ guix package -s crypto -s library | \
1849 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1853 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1854 information on @dfn{selection expressions} for @code{recsel -e}.
1856 @item --show=@var{package}
1857 Show details about @var{package}, taken from the list of available packages, in
1858 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1862 $ guix package --show=python | recsel -p name,version
1870 You may also specify the full name of a package to only get details about a
1871 specific version of it:
1873 $ guix package --show=python@@3.4 | recsel -p name,version
1880 @item --list-installed[=@var{regexp}]
1881 @itemx -I [@var{regexp}]
1882 List the currently installed packages in the specified profile, with the
1883 most recently installed packages shown last. When @var{regexp} is
1884 specified, list only installed packages whose name matches @var{regexp}.
1886 For each installed package, print the following items, separated by
1887 tabs: the package name, its version string, the part of the package that
1888 is installed (for instance, @code{out} for the default output,
1889 @code{include} for its headers, etc.), and the path of this package in
1892 @item --list-available[=@var{regexp}]
1893 @itemx -A [@var{regexp}]
1894 List packages currently available in the distribution for this system
1895 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
1896 installed packages whose name matches @var{regexp}.
1898 For each package, print the following items separated by tabs: its name,
1899 its version string, the parts of the package (@pxref{Packages with
1900 Multiple Outputs}), and the source location of its definition.
1902 @item --list-generations[=@var{pattern}]
1903 @itemx -l [@var{pattern}]
1905 Return a list of generations along with their creation dates; for each
1906 generation, show the installed packages, with the most recently
1907 installed packages shown last. Note that the zeroth generation is never
1910 For each installed package, print the following items, separated by
1911 tabs: the name of a package, its version string, the part of the package
1912 that is installed (@pxref{Packages with Multiple Outputs}), and the
1913 location of this package in the store.
1915 When @var{pattern} is used, the command returns only matching
1916 generations. Valid patterns include:
1919 @item @emph{Integers and comma-separated integers}. Both patterns denote
1920 generation numbers. For instance, @code{--list-generations=1} returns
1923 And @code{--list-generations=1,8,2} outputs three generations in the
1924 specified order. Neither spaces nor trailing commas are allowed.
1926 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
1927 specified generations and everything in between. Note that the start of
1928 a range must be smaller than its end.
1930 It is also possible to omit the endpoint. For example,
1931 @code{--list-generations=2..}, returns all generations starting from the
1934 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
1935 or months by passing an integer along with the first letter of the
1936 duration. For example, @code{--list-generations=20d} lists generations
1937 that are up to 20 days old.
1940 @item --delete-generations[=@var{pattern}]
1941 @itemx -d [@var{pattern}]
1942 When @var{pattern} is omitted, delete all generations except the current
1945 This command accepts the same patterns as @option{--list-generations}.
1946 When @var{pattern} is specified, delete the matching generations. When
1947 @var{pattern} specifies a duration, generations @emph{older} than the
1948 specified duration match. For instance, @code{--delete-generations=1m}
1949 deletes generations that are more than one month old.
1951 If the current generation matches, it is @emph{not} deleted. Also, the
1952 zeroth generation is never deleted.
1954 Note that deleting generations prevents rolling back to them.
1955 Consequently, this command must be used with care.
1959 Finally, since @command{guix package} may actually start build
1960 processes, it supports all the common build options (@pxref{Common Build
1961 Options}). It also supports package transformation options, such as
1962 @option{--with-source} (@pxref{Package Transformation Options}).
1963 However, note that package transformations are lost when upgrading; to
1964 preserve transformations across upgrades, you should define your own
1965 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
1966 (@pxref{Defining Packages}).
1970 @section Substitutes
1973 @cindex pre-built binaries
1974 Guix supports transparent source/binary deployment, which means that it
1975 can either build things locally, or download pre-built items from a
1976 server. We call these pre-built items @dfn{substitutes}---they are
1977 substitutes for local build results. In many cases, downloading a
1978 substitute is much faster than building things locally.
1980 Substitutes can be anything resulting from a derivation build
1981 (@pxref{Derivations}). Of course, in the common case, they are
1982 pre-built package binaries, but source tarballs, for instance, which
1983 also result from derivation builds, can be available as substitutes.
1985 The @code{hydra.gnu.org} server is a front-end to a build farm that
1986 builds packages from the GNU distribution continuously for some
1987 architectures, and makes them available as substitutes. This is the
1988 default source of substitutes; it can be overridden by passing the
1989 @option{--substitute-urls} option either to @command{guix-daemon}
1990 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
1991 or to client tools such as @command{guix package}
1992 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
1995 Substitute URLs can be either HTTP or HTTPS@footnote{For HTTPS access,
1996 the Guile bindings of GnuTLS must be installed. @xref{Requirements}.}
1997 HTTPS is recommended because communications are encrypted; conversely,
1998 using HTTP makes all communications visible to an eavesdropper, who
1999 could use the information gathered to determine, for instance, whether
2000 your system has unpatched security vulnerabilities.
2003 @cindex digital signatures
2004 @cindex substitutes, authorization thereof
2005 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2007 must add its public key to the access control list (ACL) of archive
2008 imports, using the @command{guix archive} command (@pxref{Invoking guix
2009 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2010 be compromised and to serve genuine substitutes.
2012 This public key is installed along with Guix, in
2013 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2014 the installation prefix of Guix. If you installed Guix from source,
2015 make sure you checked the GPG signature of
2016 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2017 Then, you can run something like this:
2020 # guix archive --authorize < hydra.gnu.org.pub
2023 Once this is in place, the output of a command like @code{guix build}
2024 should change from something like:
2027 $ guix build emacs --dry-run
2028 The following derivations would be built:
2029 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2030 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2031 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2032 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2040 $ guix build emacs --dry-run
2041 The following files would be downloaded:
2042 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2043 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2044 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2045 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2050 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2051 will be downloaded, when possible, for future builds.
2053 Guix ignores substitutes that are not signed, or that are not signed by
2054 one of the keys listed in the ACL. It also detects and raises an error
2055 when attempting to use a substitute that has been tampered with.
2058 Substitutes are downloaded over HTTP or HTTPS.
2059 The @code{http_proxy} environment
2060 variable can be set in the environment of @command{guix-daemon} and is
2061 honored for downloads of substitutes. Note that the value of
2062 @code{http_proxy} in the environment where @command{guix build},
2063 @command{guix package}, and other client commands are run has
2064 @emph{absolutely no effect}.
2066 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2067 (in other words, the server is not authenticated), contrary to what
2068 HTTPS clients such as Web browsers usually do. This is because Guix
2069 authenticates substitute information itself, as explained above, which
2070 is what we care about (whereas X.509 certificates are about
2071 authenticating bindings between domain names and public keys.)
2073 The substitute mechanism can be disabled globally by running
2074 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2075 guix-daemon}). It can also be disabled temporarily by passing the
2076 @code{--no-substitutes} option to @command{guix package}, @command{guix
2077 build}, and other command-line tools.
2080 @unnumberedsubsec On Trusting Binaries
2082 Today, each individual's control over their own computing is at the
2083 mercy of institutions, corporations, and groups with enough power and
2084 determination to subvert the computing infrastructure and exploit its
2085 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2086 convenient, we encourage users to also build on their own, or even run
2087 their own build farm, such that @code{hydra.gnu.org} is less of an
2088 interesting target. One way to help is by publishing the software you
2089 build using @command{guix publish} so that others have one more choice
2090 of server to download substitutes from (@pxref{Invoking guix publish}).
2092 Guix has the foundations to maximize build reproducibility
2093 (@pxref{Features}). In most cases, independent builds of a given
2094 package or derivation should yield bit-identical results. Thus, through
2095 a diverse set of independent package builds, we can strengthen the
2096 integrity of our systems. The @command{guix challenge} command aims to
2097 help users assess substitute servers, and to assist developers in
2098 finding out about non-deterministic package builds (@pxref{Invoking guix
2099 challenge}). Similarly, the @option{--check} option of @command{guix
2100 build} allows users to check whether previously-installed substitutes
2101 are genuine by rebuilding them locally (@pxref{build-check,
2102 @command{guix build --check}}).
2104 In the future, we want Guix to have support to publish and retrieve
2105 binaries to/from other users, in a peer-to-peer fashion. If you would
2106 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2109 @node Packages with Multiple Outputs
2110 @section Packages with Multiple Outputs
2112 @cindex multiple-output packages
2113 @cindex package outputs
2116 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2117 source package leads to exactly one directory in the store. When running
2118 @command{guix package -i glibc}, one installs the default output of the
2119 GNU libc package; the default output is called @code{out}, but its name
2120 can be omitted as shown in this command. In this particular case, the
2121 default output of @code{glibc} contains all the C header files, shared
2122 libraries, static libraries, Info documentation, and other supporting
2125 Sometimes it is more appropriate to separate the various types of files
2126 produced from a single source package into separate outputs. For
2127 instance, the GLib C library (used by GTK+ and related packages)
2128 installs more than 20 MiB of reference documentation as HTML pages.
2129 To save space for users who do not need it, the documentation goes to a
2130 separate output, called @code{doc}. To install the main GLib output,
2131 which contains everything but the documentation, one would run:
2134 guix package -i glib
2137 @cindex documentation
2138 The command to install its documentation is:
2141 guix package -i glib:doc
2144 Some packages install programs with different ``dependency footprints''.
2145 For instance, the WordNet package installs both command-line tools and
2146 graphical user interfaces (GUIs). The former depend solely on the C
2147 library, whereas the latter depend on Tcl/Tk and the underlying X
2148 libraries. In this case, we leave the command-line tools in the default
2149 output, whereas the GUIs are in a separate output. This allows users
2150 who do not need the GUIs to save space. The @command{guix size} command
2151 can help find out about such situations (@pxref{Invoking guix size}).
2152 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2154 There are several such multiple-output packages in the GNU distribution.
2155 Other conventional output names include @code{lib} for libraries and
2156 possibly header files, @code{bin} for stand-alone programs, and
2157 @code{debug} for debugging information (@pxref{Installing Debugging
2158 Files}). The outputs of a packages are listed in the third column of
2159 the output of @command{guix package --list-available} (@pxref{Invoking
2163 @node Invoking guix gc
2164 @section Invoking @command{guix gc}
2166 @cindex garbage collector
2168 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2169 The @command{guix gc} command allows users to explicitly run the garbage
2170 collector to reclaim space from the @file{/gnu/store} directory. It is
2171 the @emph{only} way to remove files from @file{/gnu/store}---removing
2172 files or directories manually may break it beyond repair!
2174 The garbage collector has a set of known @dfn{roots}: any file under
2175 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2176 cannot be deleted; any other file is considered @dfn{dead} and may be
2177 deleted. The set of garbage collector roots includes default user
2178 profiles, and may be augmented with @command{guix build --root}, for
2179 example (@pxref{Invoking guix build}).
2181 Prior to running @code{guix gc --collect-garbage} to make space, it is
2182 often useful to remove old generations from user profiles; that way, old
2183 package builds referenced by those generations can be reclaimed. This
2184 is achieved by running @code{guix package --delete-generations}
2185 (@pxref{Invoking guix package}).
2187 The @command{guix gc} command has three modes of operation: it can be
2188 used to garbage-collect any dead files (the default), to delete specific
2189 files (the @code{--delete} option), to print garbage-collector
2190 information, or for more advanced queries. The garbage collection
2191 options are as follows:
2194 @item --collect-garbage[=@var{min}]
2195 @itemx -C [@var{min}]
2196 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2197 sub-directories. This is the default operation when no option is
2200 When @var{min} is given, stop once @var{min} bytes have been collected.
2201 @var{min} may be a number of bytes, or it may include a unit as a
2202 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2203 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2205 When @var{min} is omitted, collect all the garbage.
2207 @item --free-space=@var{free}
2208 @itemx -F @var{free}
2209 Collect garbage until @var{free} space is available under
2210 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2211 as @code{500MiB}, as described above.
2213 When @var{free} or more is already available in @file{/gnu/store}, do
2214 nothing and exit immediately.
2218 Attempt to delete all the store files and directories specified as
2219 arguments. This fails if some of the files are not in the store, or if
2220 they are still live.
2222 @item --list-failures
2223 List store items corresponding to cached build failures.
2225 This prints nothing unless the daemon was started with
2226 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2227 @option{--cache-failures}}).
2229 @item --clear-failures
2230 Remove the specified store items from the failed-build cache.
2232 Again, this option only makes sense when the daemon is started with
2233 @option{--cache-failures}. Otherwise, it does nothing.
2236 Show the list of dead files and directories still present in the
2237 store---i.e., files and directories no longer reachable from any root.
2240 Show the list of live store files and directories.
2244 In addition, the references among existing store files can be queried:
2250 @cindex package dependencies
2251 List the references (respectively, the referrers) of store files given
2257 List the requisites of the store files passed as arguments. Requisites
2258 include the store files themselves, their references, and the references
2259 of these, recursively. In other words, the returned list is the
2260 @dfn{transitive closure} of the store files.
2262 @xref{Invoking guix size}, for a tool to profile the size of the closure
2263 of an element. @xref{Invoking guix graph}, for a tool to visualize
2264 the graph of references.
2268 Lastly, the following options allow you to check the integrity of the
2269 store and to control disk usage.
2273 @item --verify[=@var{options}]
2274 @cindex integrity, of the store
2275 @cindex integrity checking
2276 Verify the integrity of the store.
2278 By default, make sure that all the store items marked as valid in the
2279 database of the daemon actually exist in @file{/gnu/store}.
2281 When provided, @var{options} must be a comma-separated list containing one
2282 or more of @code{contents} and @code{repair}.
2284 When passing @option{--verify=contents}, the daemon computes the
2285 content hash of each store item and compares it against its hash in the
2286 database. Hash mismatches are reported as data corruptions. Because it
2287 traverses @emph{all the files in the store}, this command can take a
2288 long time, especially on systems with a slow disk drive.
2290 @cindex repairing the store
2291 @cindex corruption, recovering from
2292 Using @option{--verify=repair} or @option{--verify=contents,repair}
2293 causes the daemon to try to repair corrupt store items by fetching
2294 substitutes for them (@pxref{Substitutes}). Because repairing is not
2295 atomic, and thus potentially dangerous, it is available only to the
2296 system administrator. A lightweight alternative, when you know exactly
2297 which items in the store are corrupt, is @command{guix build --repair}
2298 (@pxref{Invoking guix build}).
2301 @cindex deduplication
2302 Optimize the store by hard-linking identical files---this is
2303 @dfn{deduplication}.
2305 The daemon performs deduplication after each successful build or archive
2306 import, unless it was started with @code{--disable-deduplication}
2307 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2308 this option is primarily useful when the daemon was running with
2309 @code{--disable-deduplication}.
2313 @node Invoking guix pull
2314 @section Invoking @command{guix pull}
2316 @cindex upgrading Guix
2317 @cindex updating Guix
2318 @cindex @command{guix pull}
2320 Packages are installed or upgraded to the latest version available in
2321 the distribution currently available on your local machine. To update
2322 that distribution, along with the Guix tools, you must run @command{guix
2323 pull}: the command downloads the latest Guix source code and package
2324 descriptions, and deploys it.
2326 On completion, @command{guix package} will use packages and package
2327 versions from this just-retrieved copy of Guix. Not only that, but all
2328 the Guix commands and Scheme modules will also be taken from that latest
2329 version. New @command{guix} sub-commands added by the update also
2332 Any user can update their Guix copy using @command{guix pull}, and the
2333 effect is limited to the user who run @command{guix pull}. For
2334 instance, when user @code{root} runs @command{guix pull}, this has no
2335 effect on the version of Guix that user @code{alice} sees, and vice
2336 versa@footnote{Under the hood, @command{guix pull} updates the
2337 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2338 and the @command{guix} command loads code from there.}.
2340 The @command{guix pull} command is usually invoked with no arguments,
2341 but it supports the following options:
2345 Produce verbose output, writing build logs to the standard error output.
2347 @item --url=@var{url}
2348 Download the source tarball of Guix from @var{url}.
2350 By default, the tarball is taken from its canonical address at
2351 @code{gnu.org}, for the stable branch of Guix.
2353 With some Git servers, this can be used to deploy any version of Guix.
2354 For example, to download and deploy version 0.12.0 of Guix from the
2358 guix pull --url=http://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.12.0.tar.gz
2361 It can also be used to deploy arbitrary Git revisions:
2364 guix pull --url=http://git.savannah.gnu.org/cgit/guix.git/snapshot/74d862e8a.tar.gz
2368 Use the bootstrap Guile to build the latest Guix. This option is only
2369 useful to Guix developers.
2373 @node Invoking guix archive
2374 @section Invoking @command{guix archive}
2376 @cindex @command{guix archive}
2378 The @command{guix archive} command allows users to @dfn{export} files
2379 from the store into a single archive, and to later @dfn{import} them.
2380 In particular, it allows store files to be transferred from one machine
2381 to the store on another machine.
2383 @cindex exporting store items
2384 To export store files as an archive to standard output, run:
2387 guix archive --export @var{options} @var{specifications}...
2390 @var{specifications} may be either store file names or package
2391 specifications, as for @command{guix package} (@pxref{Invoking guix
2392 package}). For instance, the following command creates an archive
2393 containing the @code{gui} output of the @code{git} package and the main
2394 output of @code{emacs}:
2397 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2400 If the specified packages are not built yet, @command{guix archive}
2401 automatically builds them. The build process may be controlled with the
2402 common build options (@pxref{Common Build Options}).
2404 To transfer the @code{emacs} package to a machine connected over SSH,
2408 guix archive --export -r emacs | ssh the-machine guix archive --import
2412 Similarly, a complete user profile may be transferred from one machine
2413 to another like this:
2416 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2417 ssh the-machine guix-archive --import
2421 However, note that, in both examples, all of @code{emacs} and the
2422 profile as well as all of their dependencies are transferred (due to
2423 @code{-r}), regardless of what is already available in the store on the
2424 target machine. The @code{--missing} option can help figure out which
2425 items are missing from the target store. The @command{guix copy}
2426 command simplifies and optimizes this whole process, so this is probably
2427 what you should use in this case (@pxref{Invoking guix copy}).
2429 @cindex nar, archive format
2430 @cindex normalized archive (nar)
2431 By default archives are stored in the ``normalized archive'' or ``nar'' format, which is
2432 comparable in spirit to `tar', but with differences
2433 that make it more appropriate for our purposes. First, rather than
2434 recording all Unix metadata for each file, the nar format only mentions
2435 the file type (regular, directory, or symbolic link); Unix permissions
2436 and owner/group are dismissed. Second, the order in which directory
2437 entries are stored always follows the order of file names according to
2438 the C locale collation order. This makes archive production fully
2441 When exporting, the daemon digitally signs the contents of the archive,
2442 and that digital signature is appended. When importing, the daemon
2443 verifies the signature and rejects the import in case of an invalid
2444 signature or if the signing key is not authorized.
2445 @c FIXME: Add xref to daemon doc about signatures.
2447 Optionally, archives can be exported as a Docker image in the tar
2448 archive format using @code{--format=docker}.
2450 The main options are:
2454 Export the specified store files or packages (see below.) Write the
2455 resulting archive to the standard output.
2457 Dependencies are @emph{not} included in the output, unless
2458 @code{--recursive} is passed.
2462 When combined with @code{--export}, this instructs @command{guix
2463 archive} to include dependencies of the given items in the archive.
2464 Thus, the resulting archive is self-contained: it contains the closure
2465 of the exported store items.
2468 Read an archive from the standard input, and import the files listed
2469 therein into the store. Abort if the archive has an invalid digital
2470 signature, or if it is signed by a public key not among the authorized
2471 keys (see @code{--authorize} below.)
2474 Read a list of store file names from the standard input, one per line,
2475 and write on the standard output the subset of these files missing from
2479 @item --format=@var{FMT}
2480 @cindex docker, export
2481 @cindex export format
2482 Specify the export format. Acceptable arguments are @code{nar} and
2483 @code{docker}. The default is the nar format. When the format is
2484 @code{docker}, recursively export the specified store directory as a
2485 Docker image in tar archive format, as specified in
2486 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2487 version 1.2.0 of the Docker Image Specification}. Using
2488 @code{--format=docker} implies @code{--recursive}. The generated
2489 archive can be loaded by Docker using @command{docker load}.
2491 @item --generate-key[=@var{parameters}]
2492 @cindex signing, archives
2493 Generate a new key pair for the daemon. This is a prerequisite before
2494 archives can be exported with @code{--export}. Note that this operation
2495 usually takes time, because it needs to gather enough entropy to
2496 generate the key pair.
2498 The generated key pair is typically stored under @file{/etc/guix}, in
2499 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2500 key, which must be kept secret.) When @var{parameters} is omitted,
2501 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2502 versions before 1.6.0, it is a 4096-bit RSA key.
2503 Alternatively, @var{parameters} can specify
2504 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2505 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2506 Libgcrypt Reference Manual}).
2509 @cindex authorizing, archives
2510 Authorize imports signed by the public key passed on standard input.
2511 The public key must be in ``s-expression advanced format''---i.e., the
2512 same format as the @file{signing-key.pub} file.
2514 The list of authorized keys is kept in the human-editable file
2515 @file{/etc/guix/acl}. The file contains
2516 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2517 s-expressions''} and is structured as an access-control list in the
2518 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2521 @item --extract=@var{directory}
2522 @itemx -x @var{directory}
2523 Read a single-item archive as served by substitute servers
2524 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2525 low-level operation needed in only very narrow use cases; see below.
2527 For example, the following command extracts the substitute for Emacs
2528 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2532 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2533 | bunzip2 | guix archive -x /tmp/emacs
2536 Single-item archives are different from multiple-item archives produced
2537 by @command{guix archive --export}; they contain a single store item,
2538 and they do @emph{not} embed a signature. Thus this operation does
2539 @emph{no} signature verification and its output should be considered
2542 The primary purpose of this operation is to facilitate inspection of
2543 archive contents coming from possibly untrusted substitute servers.
2547 @c *********************************************************************
2548 @node Programming Interface
2549 @chapter Programming Interface
2551 GNU Guix provides several Scheme programming interfaces (APIs) to
2552 define, build, and query packages. The first interface allows users to
2553 write high-level package definitions. These definitions refer to
2554 familiar packaging concepts, such as the name and version of a package,
2555 its build system, and its dependencies. These definitions can then be
2556 turned into concrete build actions.
2558 Build actions are performed by the Guix daemon, on behalf of users. In a
2559 standard setup, the daemon has write access to the store---the
2560 @file{/gnu/store} directory---whereas users do not. The recommended
2561 setup also has the daemon perform builds in chroots, under a specific
2562 build users, to minimize interference with the rest of the system.
2565 Lower-level APIs are available to interact with the daemon and the
2566 store. To instruct the daemon to perform a build action, users actually
2567 provide it with a @dfn{derivation}. A derivation is a low-level
2568 representation of the build actions to be taken, and the environment in
2569 which they should occur---derivations are to package definitions what
2570 assembly is to C programs. The term ``derivation'' comes from the fact
2571 that build results @emph{derive} from them.
2573 This chapter describes all these APIs in turn, starting from high-level
2574 package definitions.
2577 * Defining Packages:: Defining new packages.
2578 * Build Systems:: Specifying how packages are built.
2579 * The Store:: Manipulating the package store.
2580 * Derivations:: Low-level interface to package derivations.
2581 * The Store Monad:: Purely functional interface to the store.
2582 * G-Expressions:: Manipulating build expressions.
2585 @node Defining Packages
2586 @section Defining Packages
2588 The high-level interface to package definitions is implemented in the
2589 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2590 example, the package definition, or @dfn{recipe}, for the GNU Hello
2591 package looks like this:
2594 (define-module (gnu packages hello)
2595 #:use-module (guix packages)
2596 #:use-module (guix download)
2597 #:use-module (guix build-system gnu)
2598 #:use-module (guix licenses)
2599 #:use-module (gnu packages gawk))
2601 (define-public hello
2607 (uri (string-append "mirror://gnu/hello/hello-" version
2611 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2612 (build-system gnu-build-system)
2613 (arguments '(#:configure-flags '("--enable-silent-rules")))
2614 (inputs `(("gawk" ,gawk)))
2615 (synopsis "Hello, GNU world: An example GNU package")
2616 (description "Guess what GNU Hello prints!")
2617 (home-page "http://www.gnu.org/software/hello/")
2622 Without being a Scheme expert, the reader may have guessed the meaning
2623 of the various fields here. This expression binds the variable
2624 @code{hello} to a @code{<package>} object, which is essentially a record
2625 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2626 This package object can be inspected using procedures found in the
2627 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2628 returns---surprise!---@code{"hello"}.
2630 With luck, you may be able to import part or all of the definition of
2631 the package you are interested in from another repository, using the
2632 @code{guix import} command (@pxref{Invoking guix import}).
2634 In the example above, @var{hello} is defined in a module of its own,
2635 @code{(gnu packages hello)}. Technically, this is not strictly
2636 necessary, but it is convenient to do so: all the packages defined in
2637 modules under @code{(gnu packages @dots{})} are automatically known to
2638 the command-line tools (@pxref{Package Modules}).
2640 There are a few points worth noting in the above package definition:
2644 The @code{source} field of the package is an @code{<origin>} object
2645 (@pxref{origin Reference}, for the complete reference).
2646 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2647 meaning that the source is a file to be downloaded over FTP or HTTP.
2649 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2650 the GNU mirrors defined in @code{(guix download)}.
2652 The @code{sha256} field specifies the expected SHA256 hash of the file
2653 being downloaded. It is mandatory, and allows Guix to check the
2654 integrity of the file. The @code{(base32 @dots{})} form introduces the
2655 base32 representation of the hash. You can obtain this information with
2656 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2657 hash} (@pxref{Invoking guix hash}).
2660 When needed, the @code{origin} form can also have a @code{patches} field
2661 listing patches to be applied, and a @code{snippet} field giving a
2662 Scheme expression to modify the source code.
2665 @cindex GNU Build System
2666 The @code{build-system} field specifies the procedure to build the
2667 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2668 represents the familiar GNU Build System, where packages may be
2669 configured, built, and installed with the usual @code{./configure &&
2670 make && make check && make install} command sequence.
2673 The @code{arguments} field specifies options for the build system
2674 (@pxref{Build Systems}). Here it is interpreted by
2675 @var{gnu-build-system} as a request run @file{configure} with the
2676 @code{--enable-silent-rules} flag.
2682 What about these quote (@code{'}) characters? They are Scheme syntax to
2683 introduce a literal list; @code{'} is synonymous with @code{quote}.
2684 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2685 for details. Here the value of the @code{arguments} field is a list of
2686 arguments passed to the build system down the road, as with @code{apply}
2687 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2690 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2691 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2692 @code{#:configure-flags} is a keyword used to pass a keyword argument
2693 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2697 The @code{inputs} field specifies inputs to the build process---i.e.,
2698 build-time or run-time dependencies of the package. Here, we define an
2699 input called @code{"gawk"} whose value is that of the @var{gawk}
2700 variable; @var{gawk} is itself bound to a @code{<package>} object.
2702 @cindex backquote (quasiquote)
2705 @cindex comma (unquote)
2709 @findex unquote-splicing
2710 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2711 us to introduce a literal list in the @code{inputs} field, while
2712 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2713 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2716 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2717 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2718 of ensuring that they are present (@pxref{Build Systems}).
2720 However, any other dependencies need to be specified in the
2721 @code{inputs} field. Any dependency not specified here will simply be
2722 unavailable to the build process, possibly leading to a build failure.
2725 @xref{package Reference}, for a full description of possible fields.
2727 Once a package definition is in place, the
2728 package may actually be built using the @code{guix build} command-line
2729 tool (@pxref{Invoking guix build}). You can easily jump back to the
2730 package definition using the @command{guix edit} command
2731 (@pxref{Invoking guix edit}).
2732 @xref{Packaging Guidelines}, for
2733 more information on how to test package definitions, and
2734 @ref{Invoking guix lint}, for information on how to check a definition
2735 for style conformance.
2737 Finally, updating the package definition to a new upstream version
2738 can be partly automated by the @command{guix refresh} command
2739 (@pxref{Invoking guix refresh}).
2741 Behind the scenes, a derivation corresponding to the @code{<package>}
2742 object is first computed by the @code{package-derivation} procedure.
2743 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
2744 The build actions it prescribes may then be realized by using the
2745 @code{build-derivations} procedure (@pxref{The Store}).
2747 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
2748 Return the @code{<derivation>} object of @var{package} for @var{system}
2749 (@pxref{Derivations}).
2751 @var{package} must be a valid @code{<package>} object, and @var{system}
2752 must be a string denoting the target system type---e.g.,
2753 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
2754 must be a connection to the daemon, which operates on the store
2755 (@pxref{The Store}).
2759 @cindex cross-compilation
2760 Similarly, it is possible to compute a derivation that cross-builds a
2761 package for some other system:
2763 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
2764 @var{package} @var{target} [@var{system}]
2765 Return the @code{<derivation>} object of @var{package} cross-built from
2766 @var{system} to @var{target}.
2768 @var{target} must be a valid GNU triplet denoting the target hardware
2769 and operating system, such as @code{"mips64el-linux-gnu"}
2770 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
2771 Configure and Build System}).
2774 @cindex package transformations
2775 @cindex input rewriting
2776 @cindex dependency tree rewriting
2777 Packages can be manipulated in arbitrary ways. An example of a useful
2778 transformation is @dfn{input rewriting}, whereby the dependency tree of
2779 a package is rewritten by replacing specific inputs by others:
2781 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
2782 [@var{rewrite-name}]
2783 Return a procedure that, when passed a package, replaces its direct and
2784 indirect dependencies (but not its implicit inputs) according to
2785 @var{replacements}. @var{replacements} is a list of package pairs; the
2786 first element of each pair is the package to replace, and the second one
2789 Optionally, @var{rewrite-name} is a one-argument procedure that takes
2790 the name of a package and returns its new name after rewrite.
2794 Consider this example:
2797 (define libressl-instead-of-openssl
2798 ;; This is a procedure to replace OPENSSL by LIBRESSL,
2800 (package-input-rewriting `((,openssl . ,libressl))))
2802 (define git-with-libressl
2803 (libressl-instead-of-openssl git))
2807 Here we first define a rewriting procedure that replaces @var{openssl}
2808 with @var{libressl}. Then we use it to define a @dfn{variant} of the
2809 @var{git} package that uses @var{libressl} instead of @var{openssl}.
2810 This is exactly what the @option{--with-input} command-line option does
2811 (@pxref{Package Transformation Options, @option{--with-input}}).
2814 * package Reference :: The package data type.
2815 * origin Reference:: The origin data type.
2819 @node package Reference
2820 @subsection @code{package} Reference
2822 This section summarizes all the options available in @code{package}
2823 declarations (@pxref{Defining Packages}).
2825 @deftp {Data Type} package
2826 This is the data type representing a package recipe.
2830 The name of the package, as a string.
2832 @item @code{version}
2833 The version of the package, as a string.
2836 An object telling how the source code for the package should be
2837 acquired. Most of the time, this is an @code{origin} object, which
2838 denotes a file fetched from the Internet (@pxref{origin Reference}). It
2839 can also be any other ``file-like'' object such as a @code{local-file},
2840 which denotes a file from the local file system (@pxref{G-Expressions,
2841 @code{local-file}}).
2843 @item @code{build-system}
2844 The build system that should be used to build the package (@pxref{Build
2847 @item @code{arguments} (default: @code{'()})
2848 The arguments that should be passed to the build system. This is a
2849 list, typically containing sequential keyword-value pairs.
2851 @item @code{inputs} (default: @code{'()})
2852 @itemx @code{native-inputs} (default: @code{'()})
2853 @itemx @code{propagated-inputs} (default: @code{'()})
2854 @cindex inputs, of packages
2855 These fields list dependencies of the package. Each one is a list of
2856 tuples, where each tuple has a label for the input (a string) as its
2857 first element, a package, origin, or derivation as its second element,
2858 and optionally the name of the output thereof that should be used, which
2859 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
2860 more on package outputs). For example, the list below specifies three
2864 `(("libffi" ,libffi)
2865 ("libunistring" ,libunistring)
2866 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
2869 @cindex cross compilation, package dependencies
2870 The distinction between @code{native-inputs} and @code{inputs} is
2871 necessary when considering cross-compilation. When cross-compiling,
2872 dependencies listed in @code{inputs} are built for the @emph{target}
2873 architecture; conversely, dependencies listed in @code{native-inputs}
2874 are built for the architecture of the @emph{build} machine.
2876 @code{native-inputs} is typically used to list tools needed at
2877 build time, but not at run time, such as Autoconf, Automake, pkg-config,
2878 Gettext, or Bison. @command{guix lint} can report likely mistakes in
2879 this area (@pxref{Invoking guix lint}).
2881 @anchor{package-propagated-inputs}
2882 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
2883 specified packages will be automatically installed alongside the package
2884 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
2885 package}}, for information on how @command{guix package} deals with
2888 For example this is necessary when a C/C++ library needs headers of
2889 another library to compile, or when a pkg-config file refers to another
2890 one @i{via} its @code{Requires} field.
2892 Another example where @code{propagated-inputs} is useful is for languages
2893 that lack a facility to record the run-time search path akin to the
2894 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
2895 more. To ensure that libraries written in those languages can find
2896 library code they depend on at run time, run-time dependencies must be
2897 listed in @code{propagated-inputs} rather than @code{inputs}.
2899 @item @code{self-native-input?} (default: @code{#f})
2900 This is a Boolean field telling whether the package should use itself as
2901 a native input when cross-compiling.
2903 @item @code{outputs} (default: @code{'("out")})
2904 The list of output names of the package. @xref{Packages with Multiple
2905 Outputs}, for typical uses of additional outputs.
2907 @item @code{native-search-paths} (default: @code{'()})
2908 @itemx @code{search-paths} (default: @code{'()})
2909 A list of @code{search-path-specification} objects describing
2910 search-path environment variables honored by the package.
2912 @item @code{replacement} (default: @code{#f})
2913 This must be either @code{#f} or a package object that will be used as a
2914 @dfn{replacement} for this package. @xref{Security Updates, grafts},
2917 @item @code{synopsis}
2918 A one-line description of the package.
2920 @item @code{description}
2921 A more elaborate description of the package.
2923 @item @code{license}
2924 @cindex license, of packages
2925 The license of the package; a value from @code{(guix licenses)},
2926 or a list of such values.
2928 @item @code{home-page}
2929 The URL to the home-page of the package, as a string.
2931 @item @code{supported-systems} (default: @var{%supported-systems})
2932 The list of systems supported by the package, as strings of the form
2933 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
2935 @item @code{maintainers} (default: @code{'()})
2936 The list of maintainers of the package, as @code{maintainer} objects.
2938 @item @code{location} (default: source location of the @code{package} form)
2939 The source location of the package. It is useful to override this when
2940 inheriting from another package, in which case this field is not
2941 automatically corrected.
2946 @node origin Reference
2947 @subsection @code{origin} Reference
2949 This section summarizes all the options available in @code{origin}
2950 declarations (@pxref{Defining Packages}).
2952 @deftp {Data Type} origin
2953 This is the data type representing a source code origin.
2957 An object containing the URI of the source. The object type depends on
2958 the @code{method} (see below). For example, when using the
2959 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
2960 values are: a URL represented as a string, or a list thereof.
2963 A procedure that handles the URI.
2968 @item @var{url-fetch} from @code{(guix download)}
2969 download a file from the HTTP, HTTPS, or FTP URL specified in the
2973 @item @var{git-fetch} from @code{(guix git-download)}
2974 clone the Git version control repository, and check out the revision
2975 specified in the @code{uri} field as a @code{git-reference} object; a
2976 @code{git-reference} looks like this:
2980 (url "git://git.debian.org/git/pkg-shadow/shadow")
2981 (commit "v4.1.5.1"))
2986 A bytevector containing the SHA-256 hash of the source. Typically the
2987 @code{base32} form is used here to generate the bytevector from a
2990 You can obtain this information using @code{guix download}
2991 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
2994 @item @code{file-name} (default: @code{#f})
2995 The file name under which the source code should be saved. When this is
2996 @code{#f}, a sensible default value will be used in most cases. In case
2997 the source is fetched from a URL, the file name from the URL will be
2998 used. For version control checkouts, it is recommended to provide the
2999 file name explicitly because the default is not very descriptive.
3001 @item @code{patches} (default: @code{'()})
3002 A list of file names containing patches to be applied to the source.
3004 This list of patches must be unconditional. In particular, it cannot
3005 depend on the value of @code{%current-system} or
3006 @code{%current-target-system}.
3008 @item @code{snippet} (default: @code{#f})
3009 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3010 in the source directory. This is a convenient way to modify the source,
3011 sometimes more convenient than a patch.
3013 @item @code{patch-flags} (default: @code{'("-p1")})
3014 A list of command-line flags that should be passed to the @code{patch}
3017 @item @code{patch-inputs} (default: @code{#f})
3018 Input packages or derivations to the patching process. When this is
3019 @code{#f}, the usual set of inputs necessary for patching are provided,
3020 such as GNU@tie{}Patch.
3022 @item @code{modules} (default: @code{'()})
3023 A list of Guile modules that should be loaded during the patching
3024 process and while running the code in the @code{snippet} field.
3026 @item @code{patch-guile} (default: @code{#f})
3027 The Guile package that should be used in the patching process. When
3028 this is @code{#f}, a sensible default is used.
3034 @section Build Systems
3036 @cindex build system
3037 Each package definition specifies a @dfn{build system} and arguments for
3038 that build system (@pxref{Defining Packages}). This @code{build-system}
3039 field represents the build procedure of the package, as well as implicit
3040 dependencies of that build procedure.
3042 Build systems are @code{<build-system>} objects. The interface to
3043 create and manipulate them is provided by the @code{(guix build-system)}
3044 module, and actual build systems are exported by specific modules.
3046 @cindex bag (low-level package representation)
3047 Under the hood, build systems first compile package objects to
3048 @dfn{bags}. A @dfn{bag} is like a package, but with less
3049 ornamentation---in other words, a bag is a lower-level representation of
3050 a package, which includes all the inputs of that package, including some
3051 that were implicitly added by the build system. This intermediate
3052 representation is then compiled to a derivation (@pxref{Derivations}).
3054 Build systems accept an optional list of @dfn{arguments}. In package
3055 definitions, these are passed @i{via} the @code{arguments} field
3056 (@pxref{Defining Packages}). They are typically keyword arguments
3057 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3058 Guile Reference Manual}). The value of these arguments is usually
3059 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3060 by the daemon (@pxref{Derivations}).
3062 The main build system is @var{gnu-build-system}, which implements the
3063 standard build procedure for GNU and many other packages. It
3064 is provided by the @code{(guix build-system gnu)} module.
3066 @defvr {Scheme Variable} gnu-build-system
3067 @var{gnu-build-system} represents the GNU Build System, and variants
3068 thereof (@pxref{Configuration, configuration and makefile conventions,,
3069 standards, GNU Coding Standards}).
3071 @cindex build phases
3072 In a nutshell, packages using it are configured, built, and installed with
3073 the usual @code{./configure && make && make check && make install}
3074 command sequence. In practice, a few additional steps are often needed.
3075 All these steps are split up in separate @dfn{phases},
3076 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3077 modules for more details about the build phases.}:
3081 Unpack the source tarball, and change the current directory to the
3082 extracted source tree. If the source is actually a directory, copy it
3083 to the build tree, and enter that directory.
3085 @item patch-source-shebangs
3086 Patch shebangs encountered in source files so they refer to the right
3087 store file names. For instance, this changes @code{#!/bin/sh} to
3088 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3091 Run the @file{configure} script with a number of default options, such
3092 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3093 by the @code{#:configure-flags} argument.
3096 Run @code{make} with the list of flags specified with
3097 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3098 (the default), build with @code{make -j}.
3101 Run @code{make check}, or some other target specified with
3102 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3103 @code{#:parallel-tests?} argument is true (the default), run @code{make
3107 Run @code{make install} with the flags listed in @code{#:make-flags}.
3109 @item patch-shebangs
3110 Patch shebangs on the installed executable files.
3113 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3114 is false), copying them to the @code{debug} output when available
3115 (@pxref{Installing Debugging Files}).
3118 @vindex %standard-phases
3119 The build-side module @code{(guix build gnu-build-system)} defines
3120 @var{%standard-phases} as the default list of build phases.
3121 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3122 procedure implements the actual phase.
3124 The list of phases used for a particular package can be changed with the
3125 @code{#:phases} parameter. For instance, passing:
3128 #:phases (modify-phases %standard-phases (delete 'configure))
3131 means that all the phases described above will be used, except the
3132 @code{configure} phase.
3134 In addition, this build system ensures that the ``standard'' environment
3135 for GNU packages is available. This includes tools such as GCC, libc,
3136 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3137 build-system gnu)} module for a complete list). We call these the
3138 @dfn{implicit inputs} of a package, because package definitions do not
3139 have to mention them.
3142 Other @code{<build-system>} objects are defined to support other
3143 conventions and tools used by free software packages. They inherit most
3144 of @var{gnu-build-system}, and differ mainly in the set of inputs
3145 implicitly added to the build process, and in the list of phases
3146 executed. Some of these build systems are listed below.
3148 @defvr {Scheme Variable} ant-build-system
3149 This variable is exported by @code{(guix build-system ant)}. It
3150 implements the build procedure for Java packages that can be built with
3151 @url{http://ant.apache.org/, Ant build tool}.
3153 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3154 provided by the @code{icedtea} package to the set of inputs. Different
3155 packages can be specified with the @code{#:ant} and @code{#:jdk}
3156 parameters, respectively.
3158 When the original package does not provide a suitable Ant build file,
3159 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3160 build file @file{build.xml} with tasks to build the specified jar
3163 The parameter @code{#:build-target} can be used to specify the Ant task
3164 that should be run during the @code{build} phase. By default the
3165 ``jar'' task will be run.
3169 @defvr {Scheme Variable} asdf-build-system/source
3170 @defvrx {Scheme Variable} asdf-build-system/sbcl
3171 @defvrx {Scheme Variable} asdf-build-system/ecl
3173 These variables, exported by @code{(guix build-system asdf)}, implement
3174 build procedures for Common Lisp packages using
3175 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3176 definition facility for Common Lisp programs and libraries.
3178 The @code{asdf-build-system/source} system installs the packages in
3179 source form, and can be loaded using any common lisp implementation, via
3180 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3181 systems in the format which a particular implementation understands.
3182 These build systems can also be used to produce executable programs, or
3183 lisp images which contain a set of packages pre-loaded.
3185 The build system uses naming conventions. For binary packages, the
3186 package itself as well as its run-time dependencies should begin their
3187 name with the lisp implementation, such as @code{sbcl-} for
3188 @code{asdf-build-system/sbcl}. Beginning the input name with this
3189 prefix will allow the build system to encode its location into the
3190 resulting library, so that the input can be found at run-time.
3192 If dependencies are used only for tests, it is convenient to use a
3193 different prefix in order to avoid having a run-time dependency on such
3194 systems. For example,
3197 (define-public sbcl-bordeaux-threads
3200 (native-inputs `(("tests:cl-fiveam" ,sbcl-fiveam)))
3204 Additionally, the corresponding source package should be labeled using
3205 the same convention as python packages (see @ref{Python Modules}), using
3206 the @code{cl-} prefix.
3208 For binary packages, each system should be defined as a Guix package.
3209 If one package @code{origin} contains several systems, package variants
3210 can be created in order to build all the systems. Source packages,
3211 which use @code{asdf-build-system/source}, may contain several systems.
3213 In order to create executable programs and images, the build-side
3214 procedures @code{build-program} and @code{build-image} can be used.
3215 They should be called in a build phase after the @code{create-symlinks}
3216 phase, so that the system which was just built can be used within the
3217 resulting image. @code{build-program} requires a list of Common Lisp
3218 expressions to be passed as the @code{#:entry-program} argument.
3220 If the system is not defined within its own @code{.asd} file of the same
3221 name, then the @code{#:asd-file} parameter should be used to specify
3222 which file the system is defined in.
3226 @defvr {Scheme Variable} cargo-build-system
3227 @cindex Rust programming language
3228 @cindex Cargo (Rust build system)
3229 This variable is exported by @code{(guix build-system cargo)}. It
3230 supports builds of packages using Cargo, the build tool of the
3231 @uref{https://www.rust-lang.org, Rust programming language}.
3233 In its @code{configure} phase, this build system replaces dependencies
3234 specified in the @file{Carto.toml} file with inputs to the Guix package.
3235 The @code{install} phase installs the binaries, and it also installs the
3236 source code and @file{Cargo.toml} file.
3239 @defvr {Scheme Variable} cmake-build-system
3240 This variable is exported by @code{(guix build-system cmake)}. It
3241 implements the build procedure for packages using the
3242 @url{http://www.cmake.org, CMake build tool}.
3244 It automatically adds the @code{cmake} package to the set of inputs.
3245 Which package is used can be specified with the @code{#:cmake}
3248 The @code{#:configure-flags} parameter is taken as a list of flags
3249 passed to the @command{cmake} command. The @code{#:build-type}
3250 parameter specifies in abstract terms the flags passed to the compiler;
3251 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3252 debugging information''), which roughly means that code is compiled with
3253 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3256 @defvr {Scheme Variable} glib-or-gtk-build-system
3257 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3258 is intended for use with packages making use of GLib or GTK+.
3260 This build system adds the following two phases to the ones defined by
3261 @var{gnu-build-system}:
3264 @item glib-or-gtk-wrap
3265 The phase @code{glib-or-gtk-wrap} ensures that programs in
3266 @file{bin/} are able to find GLib ``schemas'' and
3267 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3268 modules}. This is achieved by wrapping the programs in launch scripts
3269 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3270 environment variables.
3272 It is possible to exclude specific package outputs from that wrapping
3273 process by listing their names in the
3274 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3275 when an output is known not to contain any GLib or GTK+ binaries, and
3276 where wrapping would gratuitously add a dependency of that output on
3279 @item glib-or-gtk-compile-schemas
3280 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3281 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3282 GSettings schemas} of GLib are compiled. Compilation is performed by the
3283 @command{glib-compile-schemas} program. It is provided by the package
3284 @code{glib:bin} which is automatically imported by the build system.
3285 The @code{glib} package providing @command{glib-compile-schemas} can be
3286 specified with the @code{#:glib} parameter.
3289 Both phases are executed after the @code{install} phase.
3292 @defvr {Scheme Variable} python-build-system
3293 This variable is exported by @code{(guix build-system python)}. It
3294 implements the more or less standard build procedure used by Python
3295 packages, which consists in running @code{python setup.py build} and
3296 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3298 For packages that install stand-alone Python programs under @code{bin/},
3299 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3300 environment variable points to all the Python libraries they depend on.
3302 Which Python package is used to perform the build can be specified with
3303 the @code{#:python} parameter. This is a useful way to force a package
3304 to be built for a specific version of the Python interpreter, which
3305 might be necessary if the package is only compatible with a single
3306 interpreter version.
3308 By default guix calls @code{setup.py} under control of
3309 @code{setuptools}, much like @command{pip} does. Some packages are not
3310 compatible with setuptools (and pip), thus you can disable this by
3311 setting the @code{#:use-setuptools} parameter to @code{#f}.
3314 @defvr {Scheme Variable} perl-build-system
3315 This variable is exported by @code{(guix build-system perl)}. It
3316 implements the standard build procedure for Perl packages, which either
3317 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3318 followed by @code{Build} and @code{Build install}; or in running
3319 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3320 @code{make} and @code{make install}, depending on which of
3321 @code{Build.PL} or @code{Makefile.PL} is present in the package
3322 distribution. Preference is given to the former if both @code{Build.PL}
3323 and @code{Makefile.PL} exist in the package distribution. This
3324 preference can be reversed by specifying @code{#t} for the
3325 @code{#:make-maker?} parameter.
3327 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3328 passes flags specified by the @code{#:make-maker-flags} or
3329 @code{#:module-build-flags} parameter, respectively.
3331 Which Perl package is used can be specified with @code{#:perl}.
3334 @defvr {Scheme Variable} r-build-system
3335 This variable is exported by @code{(guix build-system r)}. It
3336 implements the build procedure used by @uref{http://r-project.org, R}
3337 packages, which essentially is little more than running @code{R CMD
3338 INSTALL --library=/gnu/store/@dots{}} in an environment where
3339 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3340 are run after installation using the R function
3341 @code{tools::testInstalledPackage}.
3344 @defvr {Scheme Variable} ruby-build-system
3345 This variable is exported by @code{(guix build-system ruby)}. It
3346 implements the RubyGems build procedure used by Ruby packages, which
3347 involves running @code{gem build} followed by @code{gem install}.
3349 The @code{source} field of a package that uses this build system
3350 typically references a gem archive, since this is the format that Ruby
3351 developers use when releasing their software. The build system unpacks
3352 the gem archive, potentially patches the source, runs the test suite,
3353 repackages the gem, and installs it. Additionally, directories and
3354 tarballs may be referenced to allow building unreleased gems from Git or
3355 a traditional source release tarball.
3357 Which Ruby package is used can be specified with the @code{#:ruby}
3358 parameter. A list of additional flags to be passed to the @command{gem}
3359 command can be specified with the @code{#:gem-flags} parameter.
3362 @defvr {Scheme Variable} waf-build-system
3363 This variable is exported by @code{(guix build-system waf)}. It
3364 implements a build procedure around the @code{waf} script. The common
3365 phases---@code{configure}, @code{build}, and @code{install}---are
3366 implemented by passing their names as arguments to the @code{waf}
3369 The @code{waf} script is executed by the Python interpreter. Which
3370 Python package is used to run the script can be specified with the
3371 @code{#:python} parameter.
3374 @defvr {Scheme Variable} haskell-build-system
3375 This variable is exported by @code{(guix build-system haskell)}. It
3376 implements the Cabal build procedure used by Haskell packages, which
3377 involves running @code{runhaskell Setup.hs configure
3378 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3379 Instead of installing the package by running @code{runhaskell Setup.hs
3380 install}, to avoid trying to register libraries in the read-only
3381 compiler store directory, the build system uses @code{runhaskell
3382 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3383 addition, the build system generates the package documentation by
3384 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3385 is passed. Optional Haddock parameters can be passed with the help of
3386 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3387 not found, the build system looks for @code{Setup.lhs} instead.
3389 Which Haskell compiler is used can be specified with the @code{#:haskell}
3390 parameter which defaults to @code{ghc}.
3393 @defvr {Scheme Variable} emacs-build-system
3394 This variable is exported by @code{(guix build-system emacs)}. It
3395 implements an installation procedure similar to the packaging system
3396 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3398 It first creates the @code{@var{package}-autoloads.el} file, then it
3399 byte compiles all Emacs Lisp files. Differently from the Emacs
3400 packaging system, the Info documentation files are moved to the standard
3401 documentation directory and the @file{dir} file is deleted. Each
3402 package is installed in its own directory under
3403 @file{share/emacs/site-lisp/guix.d}.
3406 Lastly, for packages that do not need anything as sophisticated, a
3407 ``trivial'' build system is provided. It is trivial in the sense that
3408 it provides basically no support: it does not pull any implicit inputs,
3409 and does not have a notion of build phases.
3411 @defvr {Scheme Variable} trivial-build-system
3412 This variable is exported by @code{(guix build-system trivial)}.
3414 This build system requires a @code{#:builder} argument. This argument
3415 must be a Scheme expression that builds the package output(s)---as
3416 with @code{build-expression->derivation} (@pxref{Derivations,
3417 @code{build-expression->derivation}}).
3427 Conceptually, the @dfn{store} is the place where derivations that have
3428 been built successfully are stored---by default, @file{/gnu/store}.
3429 Sub-directories in the store are referred to as @dfn{store items} or
3430 sometimes @dfn{store paths}. The store has an associated database that
3431 contains information such as the store paths referred to by each store
3432 path, and the list of @emph{valid} store items---results of successful
3433 builds. This database resides in @file{@var{localstatedir}/guix/db},
3434 where @var{localstatedir} is the state directory specified @i{via}
3435 @option{--localstatedir} at configure time, usually @file{/var}.
3437 The store is @emph{always} accessed by the daemon on behalf of its clients
3438 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3439 connect to the daemon over a Unix-domain socket, send requests to it,
3440 and read the result---these are remote procedure calls, or RPCs.
3443 Users must @emph{never} modify files under @file{/gnu/store} directly.
3444 This would lead to inconsistencies and break the immutability
3445 assumptions of Guix's functional model (@pxref{Introduction}).
3447 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3448 how to check the integrity of the store and attempt recovery from
3449 accidental modifications.
3452 The @code{(guix store)} module provides procedures to connect to the
3453 daemon, and to perform RPCs. These are described below.
3455 @deffn {Scheme Procedure} open-connection [@var{file}] [#:reserve-space? #t]
3456 Connect to the daemon over the Unix-domain socket at @var{file}. When
3457 @var{reserve-space?} is true, instruct it to reserve a little bit of
3458 extra space on the file system so that the garbage collector can still
3459 operate should the disk become full. Return a server object.
3461 @var{file} defaults to @var{%default-socket-path}, which is the normal
3462 location given the options that were passed to @command{configure}.
3465 @deffn {Scheme Procedure} close-connection @var{server}
3466 Close the connection to @var{server}.
3469 @defvr {Scheme Variable} current-build-output-port
3470 This variable is bound to a SRFI-39 parameter, which refers to the port
3471 where build and error logs sent by the daemon should be written.
3474 Procedures that make RPCs all take a server object as their first
3477 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3478 @cindex invalid store items
3479 Return @code{#t} when @var{path} designates a valid store item and
3480 @code{#f} otherwise (an invalid item may exist on disk but still be
3481 invalid, for instance because it is the result of an aborted or failed
3484 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3485 prefixed by the store directory (@file{/gnu/store}).
3488 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3489 Add @var{text} under file @var{name} in the store, and return its store
3490 path. @var{references} is the list of store paths referred to by the
3491 resulting store path.
3494 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3495 Build @var{derivations} (a list of @code{<derivation>} objects or
3496 derivation paths), and return when the worker is done building them.
3497 Return @code{#t} on success.
3500 Note that the @code{(guix monads)} module provides a monad as well as
3501 monadic versions of the above procedures, with the goal of making it
3502 more convenient to work with code that accesses the store (@pxref{The
3506 @i{This section is currently incomplete.}
3509 @section Derivations
3512 Low-level build actions and the environment in which they are performed
3513 are represented by @dfn{derivations}. A derivation contains the
3514 following pieces of information:
3518 The outputs of the derivation---derivations produce at least one file or
3519 directory in the store, but may produce more.
3522 The inputs of the derivations, which may be other derivations or plain
3523 files in the store (patches, build scripts, etc.)
3526 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3529 The file name of a build script in the store, along with the arguments
3533 A list of environment variables to be defined.
3537 @cindex derivation path
3538 Derivations allow clients of the daemon to communicate build actions to
3539 the store. They exist in two forms: as an in-memory representation,
3540 both on the client- and daemon-side, and as files in the store whose
3541 name end in @code{.drv}---these files are referred to as @dfn{derivation
3542 paths}. Derivations paths can be passed to the @code{build-derivations}
3543 procedure to perform the build actions they prescribe (@pxref{The
3546 The @code{(guix derivations)} module provides a representation of
3547 derivations as Scheme objects, along with procedures to create and
3548 otherwise manipulate derivations. The lowest-level primitive to create
3549 a derivation is the @code{derivation} procedure:
3551 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3552 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3553 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3554 [#:system (%current-system)] [#:references-graphs #f] @
3555 [#:allowed-references #f] [#:disallowed-references #f] @
3556 [#:leaked-env-vars #f] [#:local-build? #f] @
3557 [#:substitutable? #t]
3558 Build a derivation with the given arguments, and return the resulting
3559 @code{<derivation>} object.
3561 When @var{hash} and @var{hash-algo} are given, a
3562 @dfn{fixed-output derivation} is created---i.e., one whose result is
3563 known in advance, such as a file download. If, in addition,
3564 @var{recursive?} is true, then that fixed output may be an executable
3565 file or a directory and @var{hash} must be the hash of an archive
3566 containing this output.
3568 When @var{references-graphs} is true, it must be a list of file
3569 name/store path pairs. In that case, the reference graph of each store
3570 path is exported in the build environment in the corresponding file, in
3571 a simple text format.
3573 When @var{allowed-references} is true, it must be a list of store items
3574 or outputs that the derivation's output may refer to. Likewise,
3575 @var{disallowed-references}, if true, must be a list of things the
3576 outputs may @emph{not} refer to.
3578 When @var{leaked-env-vars} is true, it must be a list of strings
3579 denoting environment variables that are allowed to ``leak'' from the
3580 daemon's environment to the build environment. This is only applicable
3581 to fixed-output derivations---i.e., when @var{hash} is true. The main
3582 use is to allow variables such as @code{http_proxy} to be passed to
3583 derivations that download files.
3585 When @var{local-build?} is true, declare that the derivation is not a
3586 good candidate for offloading and should rather be built locally
3587 (@pxref{Daemon Offload Setup}). This is the case for small derivations
3588 where the costs of data transfers would outweigh the benefits.
3590 When @var{substitutable?} is false, declare that substitutes of the
3591 derivation's output should not be used (@pxref{Substitutes}). This is
3592 useful, for instance, when building packages that capture details of the
3593 host CPU instruction set.
3597 Here's an example with a shell script as its builder, assuming
3598 @var{store} is an open connection to the daemon, and @var{bash} points
3599 to a Bash executable in the store:
3602 (use-modules (guix utils)
3606 (let ((builder ; add the Bash script to the store
3607 (add-text-to-store store "my-builder.sh"
3608 "echo hello world > $out\n" '())))
3609 (derivation store "foo"
3610 bash `("-e" ,builder)
3611 #:inputs `((,bash) (,builder))
3612 #:env-vars '(("HOME" . "/homeless"))))
3613 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
3616 As can be guessed, this primitive is cumbersome to use directly. A
3617 better approach is to write build scripts in Scheme, of course! The
3618 best course of action for that is to write the build code as a
3619 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
3620 information, @pxref{G-Expressions}.
3622 Once upon a time, @code{gexp->derivation} did not exist and constructing
3623 derivations with build code written in Scheme was achieved with
3624 @code{build-expression->derivation}, documented below. This procedure
3625 is now deprecated in favor of the much nicer @code{gexp->derivation}.
3627 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
3628 @var{name} @var{exp} @
3629 [#:system (%current-system)] [#:inputs '()] @
3630 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3631 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3632 [#:references-graphs #f] [#:allowed-references #f] @
3633 [#:disallowed-references #f] @
3634 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3635 Return a derivation that executes Scheme expression @var{exp} as a
3636 builder for derivation @var{name}. @var{inputs} must be a list of
3637 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
3638 @code{"out"} is assumed. @var{modules} is a list of names of Guile
3639 modules from the current search path to be copied in the store,
3640 compiled, and made available in the load path during the execution of
3641 @var{exp}---e.g., @code{((guix build utils) (guix build
3642 gnu-build-system))}.
3644 @var{exp} is evaluated in an environment where @code{%outputs} is bound
3645 to a list of output/path pairs, and where @code{%build-inputs} is bound
3646 to a list of string/output-path pairs made from @var{inputs}.
3647 Optionally, @var{env-vars} is a list of string pairs specifying the name
3648 and value of environment variables visible to the builder. The builder
3649 terminates by passing the result of @var{exp} to @code{exit}; thus, when
3650 @var{exp} returns @code{#f}, the build is considered to have failed.
3652 @var{exp} is built using @var{guile-for-build} (a derivation). When
3653 @var{guile-for-build} is omitted or is @code{#f}, the value of the
3654 @code{%guile-for-build} fluid is used instead.
3656 See the @code{derivation} procedure for the meaning of
3657 @var{references-graphs}, @var{allowed-references},
3658 @var{disallowed-references}, @var{local-build?}, and
3659 @var{substitutable?}.
3663 Here's an example of a single-output derivation that creates a directory
3664 containing one file:
3667 (let ((builder '(let ((out (assoc-ref %outputs "out")))
3668 (mkdir out) ; create /gnu/store/@dots{}-goo
3669 (call-with-output-file (string-append out "/test")
3671 (display '(hello guix) p))))))
3672 (build-expression->derivation store "goo" builder))
3674 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
3678 @node The Store Monad
3679 @section The Store Monad
3683 The procedures that operate on the store described in the previous
3684 sections all take an open connection to the build daemon as their first
3685 argument. Although the underlying model is functional, they either have
3686 side effects or depend on the current state of the store.
3688 The former is inconvenient: the connection to the build daemon has to be
3689 carried around in all those functions, making it impossible to compose
3690 functions that do not take that parameter with functions that do. The
3691 latter can be problematic: since store operations have side effects
3692 and/or depend on external state, they have to be properly sequenced.
3694 @cindex monadic values
3695 @cindex monadic functions
3696 This is where the @code{(guix monads)} module comes in. This module
3697 provides a framework for working with @dfn{monads}, and a particularly
3698 useful monad for our uses, the @dfn{store monad}. Monads are a
3699 construct that allows two things: associating ``context'' with values
3700 (in our case, the context is the store), and building sequences of
3701 computations (here computations include accesses to the store). Values
3702 in a monad---values that carry this additional context---are called
3703 @dfn{monadic values}; procedures that return such values are called
3704 @dfn{monadic procedures}.
3706 Consider this ``normal'' procedure:
3709 (define (sh-symlink store)
3710 ;; Return a derivation that symlinks the 'bash' executable.
3711 (let* ((drv (package-derivation store bash))
3712 (out (derivation->output-path drv))
3713 (sh (string-append out "/bin/bash")))
3714 (build-expression->derivation store "sh"
3715 `(symlink ,sh %output))))
3718 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
3719 as a monadic function:
3722 (define (sh-symlink)
3723 ;; Same, but return a monadic value.
3724 (mlet %store-monad ((drv (package->derivation bash)))
3725 (gexp->derivation "sh"
3726 #~(symlink (string-append #$drv "/bin/bash")
3730 There are several things to note in the second version: the @code{store}
3731 parameter is now implicit and is ``threaded'' in the calls to the
3732 @code{package->derivation} and @code{gexp->derivation} monadic
3733 procedures, and the monadic value returned by @code{package->derivation}
3734 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
3736 As it turns out, the call to @code{package->derivation} can even be
3737 omitted since it will take place implicitly, as we will see later
3738 (@pxref{G-Expressions}):
3741 (define (sh-symlink)
3742 (gexp->derivation "sh"
3743 #~(symlink (string-append #$bash "/bin/bash")
3748 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
3749 @c for the funny quote.
3750 Calling the monadic @code{sh-symlink} has no effect. As someone once
3751 said, ``you exit a monad like you exit a building on fire: by running''.
3752 So, to exit the monad and get the desired effect, one must use
3753 @code{run-with-store}:
3756 (run-with-store (open-connection) (sh-symlink))
3757 @result{} /gnu/store/...-sh-symlink
3760 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
3761 new ``meta-commands'' to make it easier to deal with monadic procedures:
3762 @code{run-in-store}, and @code{enter-store-monad}. The former is used
3763 to ``run'' a single monadic value through the store:
3766 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
3767 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
3770 The latter enters a recursive REPL, where all the return values are
3771 automatically run through the store:
3774 scheme@@(guile-user)> ,enter-store-monad
3775 store-monad@@(guile-user) [1]> (package->derivation hello)
3776 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
3777 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
3778 $3 = "/gnu/store/@dots{}-foo"
3779 store-monad@@(guile-user) [1]> ,q
3780 scheme@@(guile-user)>
3784 Note that non-monadic values cannot be returned in the
3785 @code{store-monad} REPL.
3787 The main syntactic forms to deal with monads in general are provided by
3788 the @code{(guix monads)} module and are described below.
3790 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
3791 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
3795 @deffn {Scheme Syntax} return @var{val}
3796 Return a monadic value that encapsulates @var{val}.
3799 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
3800 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
3801 procedures @var{mproc}@dots{}@footnote{This operation is commonly
3802 referred to as ``bind'', but that name denotes an unrelated procedure in
3803 Guile. Thus we use this somewhat cryptic symbol inherited from the
3804 Haskell language.}. There can be one @var{mproc} or several of them, as
3809 (with-monad %state-monad
3811 (lambda (x) (return (+ 1 x)))
3812 (lambda (x) (return (* 2 x)))))
3816 @result{} some-state
3820 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
3822 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
3824 Bind the variables @var{var} to the monadic values @var{mval} in
3825 @var{body}. The form (@var{var} -> @var{val}) binds @var{var} to the
3826 ``normal'' value @var{val}, as per @code{let}.
3828 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
3829 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
3832 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
3833 Bind @var{mexp} and the following monadic expressions in sequence,
3834 returning the result of the last expression.
3836 This is akin to @code{mlet}, except that the return values of the
3837 monadic expressions are ignored. In that sense, it is analogous to
3838 @code{begin}, but applied to monadic expressions.
3842 The @code{(guix monads)} module provides the @dfn{state monad}, which
3843 allows an additional value---the state---to be @emph{threaded} through
3844 monadic procedure calls.
3846 @defvr {Scheme Variable} %state-monad
3847 The state monad. Procedures in the state monad can access and change
3848 the state that is threaded.
3850 Consider the example below. The @code{square} procedure returns a value
3851 in the state monad. It returns the square of its argument, but also
3852 increments the current state value:
3856 (mlet %state-monad ((count (current-state)))
3857 (mbegin %state-monad
3858 (set-current-state (+ 1 count))
3861 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
3866 When ``run'' through @var{%state-monad}, we obtain that additional state
3867 value, which is the number of @code{square} calls.
3870 @deffn {Monadic Procedure} current-state
3871 Return the current state as a monadic value.
3874 @deffn {Monadic Procedure} set-current-state @var{value}
3875 Set the current state to @var{value} and return the previous state as a
3879 @deffn {Monadic Procedure} state-push @var{value}
3880 Push @var{value} to the current state, which is assumed to be a list,
3881 and return the previous state as a monadic value.
3884 @deffn {Monadic Procedure} state-pop
3885 Pop a value from the current state and return it as a monadic value.
3886 The state is assumed to be a list.
3889 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
3890 Run monadic value @var{mval} starting with @var{state} as the initial
3891 state. Return two values: the resulting value, and the resulting state.
3894 The main interface to the store monad, provided by the @code{(guix
3895 store)} module, is as follows.
3897 @defvr {Scheme Variable} %store-monad
3898 The store monad---an alias for @var{%state-monad}.
3900 Values in the store monad encapsulate accesses to the store. When its
3901 effect is needed, a value of the store monad must be ``evaluated'' by
3902 passing it to the @code{run-with-store} procedure (see below.)
3905 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
3906 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
3907 open store connection.
3910 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
3911 Return as a monadic value the absolute file name in the store of the file
3912 containing @var{text}, a string. @var{references} is a list of store items that the
3913 resulting text file refers to; it defaults to the empty list.
3916 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
3917 [#:recursive? #t] [#:select? (const #t)]
3918 Return the name of @var{file} once interned in the store. Use
3919 @var{name} as its store name, or the basename of @var{file} if
3920 @var{name} is omitted.
3922 When @var{recursive?} is true, the contents of @var{file} are added
3923 recursively; if @var{file} designates a flat file and @var{recursive?}
3924 is true, its contents are added, and its permission bits are kept.
3926 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
3927 @var{stat})} for each directory entry, where @var{file} is the entry's
3928 absolute file name and @var{stat} is the result of @code{lstat}; exclude
3929 entries for which @var{select?} does not return true.
3931 The example below adds a file to the store, under two different names:
3934 (run-with-store (open-connection)
3935 (mlet %store-monad ((a (interned-file "README"))
3936 (b (interned-file "README" "LEGU-MIN")))
3937 (return (list a b))))
3939 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
3944 The @code{(guix packages)} module exports the following package-related
3947 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
3948 [#:system (%current-system)] [#:target #f] @
3951 value in the absolute file name of @var{file} within the @var{output}
3952 directory of @var{package}. When @var{file} is omitted, return the name
3953 of the @var{output} directory of @var{package}. When @var{target} is
3954 true, use it as a cross-compilation target triplet.
3957 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
3958 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
3959 @var{target} [@var{system}]
3960 Monadic version of @code{package-derivation} and
3961 @code{package-cross-derivation} (@pxref{Defining Packages}).
3966 @section G-Expressions
3968 @cindex G-expression
3969 @cindex build code quoting
3970 So we have ``derivations'', which represent a sequence of build actions
3971 to be performed to produce an item in the store (@pxref{Derivations}).
3972 These build actions are performed when asking the daemon to actually
3973 build the derivations; they are run by the daemon in a container
3974 (@pxref{Invoking guix-daemon}).
3976 @cindex strata of code
3977 It should come as no surprise that we like to write these build actions
3978 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
3979 code@footnote{The term @dfn{stratum} in this context was coined by
3980 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
3981 Kiselyov, who has written insightful
3982 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
3983 on this topic}, refers to this kind of code generation as
3984 @dfn{staging}.}: the ``host code''---code that defines packages, talks
3985 to the daemon, etc.---and the ``build code''---code that actually
3986 performs build actions, such as making directories, invoking
3987 @command{make}, etc.
3989 To describe a derivation and its build actions, one typically needs to
3990 embed build code inside host code. It boils down to manipulating build
3991 code as data, and the homoiconicity of Scheme---code has a direct
3992 representation as data---comes in handy for that. But we need more than
3993 the normal @code{quasiquote} mechanism in Scheme to construct build
3996 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
3997 S-expressions adapted to build expressions. G-expressions, or
3998 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
3999 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4000 @code{#$}, and @code{#$@@}), which are comparable to
4001 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4002 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4003 GNU Guile Reference Manual}). However, there are major differences:
4007 Gexps are meant to be written to a file and run or manipulated by other
4011 When a high-level object such as a package or derivation is unquoted
4012 inside a gexp, the result is as if its output file name had been
4016 Gexps carry information about the packages or derivations they refer to,
4017 and these dependencies are automatically added as inputs to the build
4018 processes that use them.
4021 @cindex lowering, of high-level objects in gexps
4022 This mechanism is not limited to package and derivation
4023 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4024 derivations or files in the store can be defined,
4025 such that these objects can also be inserted
4026 into gexps. For example, a useful type of high-level objects that can be
4027 inserted in a gexp is ``file-like objects'', which make it easy to
4028 add files to the store and to refer to them in
4029 derivations and such (see @code{local-file} and @code{plain-file}
4032 To illustrate the idea, here is an example of a gexp:
4039 (symlink (string-append #$coreutils "/bin/ls")
4043 This gexp can be passed to @code{gexp->derivation}; we obtain a
4044 derivation that builds a directory containing exactly one symlink to
4045 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4048 (gexp->derivation "the-thing" build-exp)
4051 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4052 substituted to the reference to the @var{coreutils} package in the
4053 actual build code, and @var{coreutils} is automatically made an input to
4054 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4055 output)}) is replaced by a string containing the directory name of the
4056 output of the derivation.
4058 @cindex cross compilation
4059 In a cross-compilation context, it is useful to distinguish between
4060 references to the @emph{native} build of a package---that can run on the
4061 host---versus references to cross builds of a package. To that end, the
4062 @code{#+} plays the same role as @code{#$}, but is a reference to a
4063 native package build:
4066 (gexp->derivation "vi"
4069 (system* (string-append #+coreutils "/bin/ln")
4071 (string-append #$emacs "/bin/emacs")
4072 (string-append #$output "/bin/vi")))
4073 #:target "mips64el-linux-gnu")
4077 In the example above, the native build of @var{coreutils} is used, so
4078 that @command{ln} can actually run on the host; but then the
4079 cross-compiled build of @var{emacs} is referenced.
4081 @cindex imported modules, for gexps
4082 @findex with-imported-modules
4083 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4084 able to use certain Guile modules from the ``host environment'' in the
4085 gexp, so those modules should be imported in the ``build environment''.
4086 The @code{with-imported-modules} form allows you to express that:
4089 (let ((build (with-imported-modules '((guix build utils))
4091 (use-modules (guix build utils))
4092 (mkdir-p (string-append #$output "/bin"))))))
4093 (gexp->derivation "empty-dir"
4096 (display "success!\n")
4101 In this example, the @code{(guix build utils)} module is automatically
4102 pulled into the isolated build environment of our gexp, such that
4103 @code{(use-modules (guix build utils))} works as expected.
4105 @cindex module closure
4106 @findex source-module-closure
4107 Usually you want the @emph{closure} of the module to be imported---i.e.,
4108 the module itself and all the modules it depends on---rather than just
4109 the module; failing to do that, attempts to use the module will fail
4110 because of missing dependent modules. The @code{source-module-closure}
4111 procedure computes the closure of a module by looking at its source file
4112 headers, which comes in handy in this case:
4115 (use-modules (guix modules)) ;for 'source-module-closure'
4117 (with-imported-modules (source-module-closure
4118 '((guix build utils)
4120 (gexp->derivation "something-with-vms"
4122 (use-modules (guix build utils)
4127 The syntactic form to construct gexps is summarized below.
4129 @deffn {Scheme Syntax} #~@var{exp}
4130 @deffnx {Scheme Syntax} (gexp @var{exp})
4131 Return a G-expression containing @var{exp}. @var{exp} may contain one
4132 or more of the following forms:
4136 @itemx (ungexp @var{obj})
4137 Introduce a reference to @var{obj}. @var{obj} may have one of the
4138 supported types, for example a package or a
4139 derivation, in which case the @code{ungexp} form is replaced by its
4140 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4142 If @var{obj} is a list, it is traversed and references to supported
4143 objects are substituted similarly.
4145 If @var{obj} is another gexp, its contents are inserted and its
4146 dependencies are added to those of the containing gexp.
4148 If @var{obj} is another kind of object, it is inserted as is.
4150 @item #$@var{obj}:@var{output}
4151 @itemx (ungexp @var{obj} @var{output})
4152 This is like the form above, but referring explicitly to the
4153 @var{output} of @var{obj}---this is useful when @var{obj} produces
4154 multiple outputs (@pxref{Packages with Multiple Outputs}).
4157 @itemx #+@var{obj}:output
4158 @itemx (ungexp-native @var{obj})
4159 @itemx (ungexp-native @var{obj} @var{output})
4160 Same as @code{ungexp}, but produces a reference to the @emph{native}
4161 build of @var{obj} when used in a cross compilation context.
4163 @item #$output[:@var{output}]
4164 @itemx (ungexp output [@var{output}])
4165 Insert a reference to derivation output @var{output}, or to the main
4166 output when @var{output} is omitted.
4168 This only makes sense for gexps passed to @code{gexp->derivation}.
4171 @itemx (ungexp-splicing @var{lst})
4172 Like the above, but splices the contents of @var{lst} inside the
4176 @itemx (ungexp-native-splicing @var{lst})
4177 Like the above, but refers to native builds of the objects listed in
4182 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4183 of the @code{gexp?} type (see below.)
4186 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4187 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4188 in their execution environment. @var{modules} must be a list of Guile
4189 module names, such as @code{'((guix build utils) (guix build gremlin))}.
4191 This form has @emph{lexical} scope: it has an effect on the gexps
4192 directly defined in @var{body}@dots{}, but not on those defined, say, in
4193 procedures called from @var{body}@dots{}.
4196 @deffn {Scheme Procedure} gexp? @var{obj}
4197 Return @code{#t} if @var{obj} is a G-expression.
4200 G-expressions are meant to be written to disk, either as code building
4201 some derivation, or as plain files in the store. The monadic procedures
4202 below allow you to do that (@pxref{The Store Monad}, for more
4203 information about monads.)
4205 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4206 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4207 [#:hash #f] [#:hash-algo #f] @
4208 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4209 [#:module-path @var{%load-path}] @
4210 [#:references-graphs #f] [#:allowed-references #f] @
4211 [#:disallowed-references #f] @
4212 [#:leaked-env-vars #f] @
4213 [#:script-name (string-append @var{name} "-builder")] @
4214 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4215 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4216 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4217 stored in a file called @var{script-name}. When @var{target} is true,
4218 it is used as the cross-compilation target triplet for packages referred
4221 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4223 make @var{modules} available in the evaluation context of @var{exp};
4224 @var{modules} is a list of names of Guile modules searched in
4225 @var{module-path} to be copied in the store, compiled, and made available in
4226 the load path during the execution of @var{exp}---e.g., @code{((guix
4227 build utils) (guix build gnu-build-system))}.
4229 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4232 When @var{references-graphs} is true, it must be a list of tuples of one of the
4236 (@var{file-name} @var{package})
4237 (@var{file-name} @var{package} @var{output})
4238 (@var{file-name} @var{derivation})
4239 (@var{file-name} @var{derivation} @var{output})
4240 (@var{file-name} @var{store-item})
4243 The right-hand-side of each element of @var{references-graphs} is automatically made
4244 an input of the build process of @var{exp}. In the build environment, each
4245 @var{file-name} contains the reference graph of the corresponding item, in a simple
4248 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4249 In the latter case, the list denotes store items that the result is allowed to
4250 refer to. Any reference to another store item will lead to a build error.
4251 Similarly for @var{disallowed-references}, which can list items that must not be
4252 referenced by the outputs.
4254 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4257 @cindex file-like objects
4258 The @code{local-file}, @code{plain-file}, @code{computed-file},
4259 @code{program-file}, and @code{scheme-file} procedures below return
4260 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4261 these objects lead to a file in the store. Consider this G-expression:
4264 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4265 #$(local-file "/tmp/my-nscd.conf"))
4268 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4269 to the store. Once expanded, for instance @i{via}
4270 @code{gexp->derivation}, the G-expression refers to that copy under
4271 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4272 does not have any effect on what the G-expression does.
4273 @code{plain-file} can be used similarly; it differs in that the file
4274 content is directly passed as a string.
4276 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4277 [#:recursive? #f] [#:select? (const #t)]
4278 Return an object representing local file @var{file} to add to the store; this
4279 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4280 up relative to the source file where this form appears. @var{file} will be added to
4281 the store under @var{name}--by default the base name of @var{file}.
4283 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4284 designates a flat file and @var{recursive?} is true, its contents are added, and its
4285 permission bits are kept.
4287 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4288 @var{stat})} for each directory entry, where @var{file} is the entry's
4289 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4290 entries for which @var{select?} does not return true.
4292 This is the declarative counterpart of the @code{interned-file} monadic
4293 procedure (@pxref{The Store Monad, @code{interned-file}}).
4296 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4297 Return an object representing a text file called @var{name} with the given
4298 @var{content} (a string) to be added to the store.
4300 This is the declarative counterpart of @code{text-file}.
4303 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4304 [#:options '(#:local-build? #t)]
4305 Return an object representing the store item @var{name}, a file or
4306 directory computed by @var{gexp}. @var{options}
4307 is a list of additional arguments to pass to @code{gexp->derivation}.
4309 This is the declarative counterpart of @code{gexp->derivation}.
4312 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4313 Return an executable script @var{name} that runs @var{exp} using
4314 @var{guile}, with @var{exp}'s imported modules in its search path.
4316 The example below builds a script that simply invokes the @command{ls}
4320 (use-modules (guix gexp) (gnu packages base))
4322 (gexp->script "list-files"
4323 #~(execl #$(file-append coreutils "/bin/ls")
4327 When ``running'' it through the store (@pxref{The Store Monad,
4328 @code{run-with-store}}), we obtain a derivation that produces an
4329 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4332 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4334 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4338 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4340 Return an object representing the executable store item @var{name} that
4341 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4344 This is the declarative counterpart of @code{gexp->script}.
4347 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4348 [#:set-load-path? #t]
4349 Return a derivation that builds a file @var{name} containing @var{exp}.
4350 When @var{set-load-path?} is true, emit code in the resulting file to
4351 set @code{%load-path} and @code{%load-compiled-path} to honor
4352 @var{exp}'s imported modules.
4354 The resulting file holds references to all the dependencies of @var{exp}
4355 or a subset thereof.
4358 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4359 Return an object representing the Scheme file @var{name} that contains
4362 This is the declarative counterpart of @code{gexp->file}.
4365 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4366 Return as a monadic value a derivation that builds a text file
4367 containing all of @var{text}. @var{text} may list, in addition to
4368 strings, objects of any type that can be used in a gexp: packages,
4369 derivations, local file objects, etc. The resulting store file holds
4370 references to all these.
4372 This variant should be preferred over @code{text-file} anytime the file
4373 to create will reference items from the store. This is typically the
4374 case when building a configuration file that embeds store file names,
4378 (define (profile.sh)
4379 ;; Return the name of a shell script in the store that
4380 ;; initializes the 'PATH' environment variable.
4381 (text-file* "profile.sh"
4382 "export PATH=" coreutils "/bin:"
4383 grep "/bin:" sed "/bin\n"))
4386 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4387 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4388 preventing them from being garbage-collected during its lifetime.
4391 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4392 Return an object representing store file @var{name} containing
4393 @var{text}. @var{text} is a sequence of strings and file-like objects,
4397 (mixed-text-file "profile"
4398 "export PATH=" coreutils "/bin:" grep "/bin")
4401 This is the declarative counterpart of @code{text-file*}.
4404 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4405 Return a file-like object that expands to the concatenation of @var{obj}
4406 and @var{suffix}, where @var{obj} is a lowerable object and each
4407 @var{suffix} is a string.
4409 As an example, consider this gexp:
4412 (gexp->script "run-uname"
4413 #~(system* #$(file-append coreutils
4417 The same effect could be achieved with:
4420 (gexp->script "run-uname"
4421 #~(system* (string-append #$coreutils
4425 There is one difference though: in the @code{file-append} case, the
4426 resulting script contains the absolute file name as a string, whereas in
4427 the second case, the resulting script contains a @code{(string-append
4428 @dots{})} expression to construct the file name @emph{at run time}.
4432 Of course, in addition to gexps embedded in ``host'' code, there are
4433 also modules containing build tools. To make it clear that they are
4434 meant to be used in the build stratum, these modules are kept in the
4435 @code{(guix build @dots{})} name space.
4437 @cindex lowering, of high-level objects in gexps
4438 Internally, high-level objects are @dfn{lowered}, using their compiler,
4439 to either derivations or store items. For instance, lowering a package
4440 yields a derivation, and lowering a @code{plain-file} yields a store
4441 item. This is achieved using the @code{lower-object} monadic procedure.
4443 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4445 Return as a value in @var{%store-monad} the derivation or store item
4446 corresponding to @var{obj} for @var{system}, cross-compiling for
4447 @var{target} if @var{target} is true. @var{obj} must be an object that
4448 has an associated gexp compiler, such as a @code{<package>}.
4452 @c *********************************************************************
4456 This section describes Guix command-line utilities. Some of them are
4457 primarily targeted at developers and users who write new package
4458 definitions, while others are more generally useful. They complement
4459 the Scheme programming interface of Guix in a convenient way.
4462 * Invoking guix build:: Building packages from the command line.
4463 * Invoking guix edit:: Editing package definitions.
4464 * Invoking guix download:: Downloading a file and printing its hash.
4465 * Invoking guix hash:: Computing the cryptographic hash of a file.
4466 * Invoking guix import:: Importing package definitions.
4467 * Invoking guix refresh:: Updating package definitions.
4468 * Invoking guix lint:: Finding errors in package definitions.
4469 * Invoking guix size:: Profiling disk usage.
4470 * Invoking guix graph:: Visualizing the graph of packages.
4471 * Invoking guix environment:: Setting up development environments.
4472 * Invoking guix publish:: Sharing substitutes.
4473 * Invoking guix challenge:: Challenging substitute servers.
4474 * Invoking guix copy:: Copying to and from a remote store.
4475 * Invoking guix container:: Process isolation.
4478 @node Invoking guix build
4479 @section Invoking @command{guix build}
4481 @cindex package building
4482 @cindex @command{guix build}
4483 The @command{guix build} command builds packages or derivations and
4484 their dependencies, and prints the resulting store paths. Note that it
4485 does not modify the user's profile---this is the job of the
4486 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4487 it is mainly useful for distribution developers.
4489 The general syntax is:
4492 guix build @var{options} @var{package-or-derivation}@dots{}
4495 As an example, the following command builds the latest versions of Emacs
4496 and of Guile, displays their build logs, and finally displays the
4497 resulting directories:
4500 guix build emacs guile
4503 Similarly, the following command builds all the available packages:
4506 guix build --quiet --keep-going \
4507 `guix package -A | cut -f1,2 --output-delimiter=@@`
4510 @var{package-or-derivation} may be either the name of a package found in
4511 the software distribution such as @code{coreutils} or
4512 @code{coreutils-8.20}, or a derivation such as
4513 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4514 package with the corresponding name (and optionally version) is searched
4515 for among the GNU distribution modules (@pxref{Package Modules}).
4517 Alternatively, the @code{--expression} option may be used to specify a
4518 Scheme expression that evaluates to a package; this is useful when
4519 disambiguating among several same-named packages or package variants is
4522 There may be zero or more @var{options}. The available options are
4523 described in the subsections below.
4526 * Common Build Options:: Build options for most commands.
4527 * Package Transformation Options:: Creating variants of packages.
4528 * Additional Build Options:: Options specific to 'guix build'.
4531 @node Common Build Options
4532 @subsection Common Build Options
4534 A number of options that control the build process are common to
4535 @command{guix build} and other commands that can spawn builds, such as
4536 @command{guix package} or @command{guix archive}. These are the
4541 @item --load-path=@var{directory}
4542 @itemx -L @var{directory}
4543 Add @var{directory} to the front of the package module search path
4544 (@pxref{Package Modules}).
4546 This allows users to define their own packages and make them visible to
4547 the command-line tools.
4551 Keep the build tree of failed builds. Thus, if a build fails, its build
4552 tree is kept under @file{/tmp}, in a directory whose name is shown at
4553 the end of the build log. This is useful when debugging build issues.
4557 Keep going when some of the derivations fail to build; return only once
4558 all the builds have either completed or failed.
4560 The default behavior is to stop as soon as one of the specified
4561 derivations has failed.
4565 Do not build the derivations.
4568 When substituting a pre-built binary fails, fall back to building
4571 @item --substitute-urls=@var{urls}
4572 @anchor{client-substitute-urls}
4573 Consider @var{urls} the whitespace-separated list of substitute source
4574 URLs, overriding the default list of URLs of @command{guix-daemon}
4575 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
4577 This means that substitutes may be downloaded from @var{urls}, provided
4578 they are signed by a key authorized by the system administrator
4579 (@pxref{Substitutes}).
4581 When @var{urls} is the empty string, substitutes are effectively
4584 @item --no-substitutes
4585 Do not use substitutes for build products. That is, always build things
4586 locally instead of allowing downloads of pre-built binaries
4587 (@pxref{Substitutes}).
4590 Do not ``graft'' packages. In practice, this means that package updates
4591 available as grafts are not applied. @xref{Security Updates}, for more
4592 information on grafts.
4594 @item --rounds=@var{n}
4595 Build each derivation @var{n} times in a row, and raise an error if
4596 consecutive build results are not bit-for-bit identical.
4598 This is a useful way to detect non-deterministic builds processes.
4599 Non-deterministic build processes are a problem because they make it
4600 practically impossible for users to @emph{verify} whether third-party
4601 binaries are genuine. @xref{Invoking guix challenge}, for more.
4603 Note that, currently, the differing build results are not kept around,
4604 so you will have to manually investigate in case of an error---e.g., by
4605 stashing one of the build results with @code{guix archive --export}
4606 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
4609 @item --no-build-hook
4610 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
4611 (@pxref{Daemon Offload Setup}). That is, always build things locally
4612 instead of offloading builds to remote machines.
4614 @item --max-silent-time=@var{seconds}
4615 When the build or substitution process remains silent for more than
4616 @var{seconds}, terminate it and report a build failure.
4618 @item --timeout=@var{seconds}
4619 Likewise, when the build or substitution process lasts for more than
4620 @var{seconds}, terminate it and report a build failure.
4622 By default there is no timeout. This behavior can be restored with
4625 @item --verbosity=@var{level}
4626 Use the given verbosity level. @var{level} must be an integer between 0
4627 and 5; higher means more verbose output. Setting a level of 4 or more
4628 may be helpful when debugging setup issues with the build daemon.
4630 @item --cores=@var{n}
4632 Allow the use of up to @var{n} CPU cores for the build. The special
4633 value @code{0} means to use as many CPU cores as available.
4635 @item --max-jobs=@var{n}
4637 Allow at most @var{n} build jobs in parallel. @xref{Invoking
4638 guix-daemon, @code{--max-jobs}}, for details about this option and the
4639 equivalent @command{guix-daemon} option.
4643 Behind the scenes, @command{guix build} is essentially an interface to
4644 the @code{package-derivation} procedure of the @code{(guix packages)}
4645 module, and to the @code{build-derivations} procedure of the @code{(guix
4646 derivations)} module.
4648 In addition to options explicitly passed on the command line,
4649 @command{guix build} and other @command{guix} commands that support
4650 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
4652 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
4653 Users can define this variable to a list of command line options that
4654 will automatically be used by @command{guix build} and other
4655 @command{guix} commands that can perform builds, as in the example
4659 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
4662 These options are parsed independently, and the result is appended to
4663 the parsed command-line options.
4667 @node Package Transformation Options
4668 @subsection Package Transformation Options
4670 @cindex package variants
4671 Another set of command-line options supported by @command{guix build}
4672 and also @command{guix package} are @dfn{package transformation
4673 options}. These are options that make it possible to define @dfn{package
4674 variants}---for instance, packages built from different source code.
4675 This is a convenient way to create customized packages on the fly
4676 without having to type in the definitions of package variants
4677 (@pxref{Defining Packages}).
4681 @item --with-source=@var{source}
4682 Use @var{source} as the source of the corresponding package.
4683 @var{source} must be a file name or a URL, as for @command{guix
4684 download} (@pxref{Invoking guix download}).
4686 The ``corresponding package'' is taken to be the one specified on the
4687 command line the name of which matches the base of @var{source}---e.g.,
4688 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
4689 package is @code{guile}. Likewise, the version string is inferred from
4690 @var{source}; in the previous example, it is @code{2.0.10}.
4692 This option allows users to try out versions of packages other than the
4693 one provided by the distribution. The example below downloads
4694 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
4695 the @code{ed} package:
4698 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
4701 As a developer, @code{--with-source} makes it easy to test release
4705 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
4708 @dots{} or to build from a checkout in a pristine environment:
4711 $ git clone git://git.sv.gnu.org/guix.git
4712 $ guix build guix --with-source=./guix
4715 @item --with-input=@var{package}=@var{replacement}
4716 Replace dependency on @var{package} by a dependency on
4717 @var{replacement}. @var{package} must be a package name, and
4718 @var{replacement} must be a package specification such as @code{guile}
4719 or @code{guile@@1.8}.
4721 For instance, the following command builds Guix, but replaces its
4722 dependency on the current stable version of Guile with a dependency on
4723 the development version of Guile, @code{guile-next}:
4726 guix build --with-input=guile=guile-next guix
4729 This is a recursive, deep replacement. So in this example, both
4730 @code{guix} and its dependency @code{guile-json} (which also depends on
4731 @code{guile}) get rebuilt against @code{guile-next}.
4733 This is implemented using the @code{package-input-rewriting} Scheme
4734 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
4736 @item --with-graft=@var{package}=@var{replacement}
4737 This is similar to @code{--with-input} but with an important difference:
4738 instead of rebuilding the whole dependency chain, @var{replacement} is
4739 built and then @dfn{grafted} onto the binaries that were initially
4740 referring to @var{package}. @xref{Security Updates}, for more
4741 information on grafts.
4743 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
4744 and all its dependencies, replacing references to the version of GnuTLS
4745 they currently refer to:
4748 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
4751 This has the advantage of being much faster than rebuilding everything.
4752 But there is a caveat: it works if and only if @var{package} and
4753 @var{replacement} are strictly compatible---for example, if they provide
4754 a library, the application binary interface (ABI) of those libraries
4755 must be compatible. If @var{replacement} is somehow incompatible with
4756 @var{package}, then the resulting package may be unusable. Use with
4761 @node Additional Build Options
4762 @subsection Additional Build Options
4764 The command-line options presented below are specific to @command{guix
4771 Build quietly, without displaying the build log. Upon completion, the
4772 build log is kept in @file{/var} (or similar) and can always be
4773 retrieved using the @option{--log-file} option.
4775 @item --file=@var{file}
4776 @itemx -f @var{file}
4778 Build the package or derivation that the code within @var{file}
4781 As an example, @var{file} might contain a package definition like this
4782 (@pxref{Defining Packages}):
4785 @verbatiminclude package-hello.scm
4788 @item --expression=@var{expr}
4789 @itemx -e @var{expr}
4790 Build the package or derivation @var{expr} evaluates to.
4792 For example, @var{expr} may be @code{(@@ (gnu packages guile)
4793 guile-1.8)}, which unambiguously designates this specific variant of
4794 version 1.8 of Guile.
4796 Alternatively, @var{expr} may be a G-expression, in which case it is used
4797 as a build program passed to @code{gexp->derivation}
4798 (@pxref{G-Expressions}).
4800 Lastly, @var{expr} may refer to a zero-argument monadic procedure
4801 (@pxref{The Store Monad}). The procedure must return a derivation as a
4802 monadic value, which is then passed through @code{run-with-store}.
4806 Build the source derivations of the packages, rather than the packages
4809 For instance, @code{guix build -S gcc} returns something like
4810 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
4813 The returned source tarball is the result of applying any patches and
4814 code snippets specified in the package @code{origin} (@pxref{Defining
4818 Fetch and return the source of @var{package-or-derivation} and all their
4819 dependencies, recursively. This is a handy way to obtain a local copy
4820 of all the source code needed to build @var{packages}, allowing you to
4821 eventually build them even without network access. It is an extension
4822 of the @code{--source} option and can accept one of the following
4823 optional argument values:
4827 This value causes the @code{--sources} option to behave in the same way
4828 as the @code{--source} option.
4831 Build the source derivations of all packages, including any source that
4832 might be listed as @code{inputs}. This is the default value.
4835 $ guix build --sources tzdata
4836 The following derivations will be built:
4837 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
4838 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
4842 Build the source derivations of all packages, as well of all transitive
4843 inputs to the packages. This can be used e.g. to
4844 prefetch package source for later offline building.
4847 $ guix build --sources=transitive tzdata
4848 The following derivations will be built:
4849 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
4850 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
4851 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
4852 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
4853 /gnu/store/@dots{}-make-4.1.tar.xz.drv
4854 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
4860 @item --system=@var{system}
4861 @itemx -s @var{system}
4862 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
4863 the system type of the build host.
4865 An example use of this is on Linux-based systems, which can emulate
4866 different personalities. For instance, passing
4867 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
4868 to build packages in a complete 32-bit environment.
4870 @item --target=@var{triplet}
4871 @cindex cross-compilation
4872 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
4873 as @code{"mips64el-linux-gnu"} (@pxref{Configuration Names, GNU
4874 configuration triplets,, configure, GNU Configure and Build System}).
4876 @anchor{build-check}
4878 @cindex determinism, checking
4879 @cindex reproducibility, checking
4880 Rebuild @var{package-or-derivation}, which are already available in the
4881 store, and raise an error if the build results are not bit-for-bit
4884 This mechanism allows you to check whether previously installed
4885 substitutes are genuine (@pxref{Substitutes}), or whether the build result
4886 of a package is deterministic. @xref{Invoking guix challenge}, for more
4887 background information and tools.
4889 When used in conjunction with @option{--keep-failed}, the differing
4890 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
4891 This makes it easy to look for differences between the two results.
4894 @cindex repairing store items
4895 @cindex corruption, recovering from
4896 Attempt to repair the specified store items, if they are corrupt, by
4897 re-downloading or rebuilding them.
4899 This operation is not atomic and thus restricted to @code{root}.
4903 Return the derivation paths, not the output paths, of the given
4906 @item --root=@var{file}
4907 @itemx -r @var{file}
4908 Make @var{file} a symlink to the result, and register it as a garbage
4912 Return the build log file names or URLs for the given
4913 @var{package-or-derivation}, or raise an error if build logs are
4916 This works regardless of how packages or derivations are specified. For
4917 instance, the following invocations are equivalent:
4920 guix build --log-file `guix build -d guile`
4921 guix build --log-file `guix build guile`
4922 guix build --log-file guile
4923 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
4926 If a log is unavailable locally, and unless @code{--no-substitutes} is
4927 passed, the command looks for a corresponding log on one of the
4928 substitute servers (as specified with @code{--substitute-urls}.)
4930 So for instance, imagine you want to see the build log of GDB on MIPS,
4931 but you are actually on an @code{x86_64} machine:
4934 $ guix build --log-file gdb -s mips64el-linux
4935 https://hydra.gnu.org/log/@dots{}-gdb-7.10
4938 You can freely access a huge library of build logs!
4942 @node Invoking guix edit
4943 @section Invoking @command{guix edit}
4945 @cindex @command{guix edit}
4946 @cindex package definition, editing
4947 So many packages, so many source files! The @command{guix edit} command
4948 facilitates the life of users and packagers by pointing their editor at
4949 the source file containing the definition of the specified packages.
4953 guix edit gcc@@4.9 vim
4957 launches the program specified in the @code{VISUAL} or in the
4958 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
4961 If you are using a Guix Git checkout (@pxref{Building from Git}), or
4962 have created your own packages on @code{GUIX_PACKAGE_PATH}
4963 (@pxref{Defining Packages}), you will be able to edit the package
4964 recipes. Otherwise, you will be able to examine the read-only recipes
4965 for packages currently in the store.
4968 @node Invoking guix download
4969 @section Invoking @command{guix download}
4971 @cindex @command{guix download}
4972 @cindex downloading package sources
4973 When writing a package definition, developers typically need to download
4974 a source tarball, compute its SHA256 hash, and write that
4975 hash in the package definition (@pxref{Defining Packages}). The
4976 @command{guix download} tool helps with this task: it downloads a file
4977 from the given URI, adds it to the store, and prints both its file name
4978 in the store and its SHA256 hash.
4980 The fact that the downloaded file is added to the store saves bandwidth:
4981 when the developer eventually tries to build the newly defined package
4982 with @command{guix build}, the source tarball will not have to be
4983 downloaded again because it is already in the store. It is also a
4984 convenient way to temporarily stash files, which may be deleted
4985 eventually (@pxref{Invoking guix gc}).
4987 The @command{guix download} command supports the same URIs as used in
4988 package definitions. In particular, it supports @code{mirror://} URIs.
4989 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
4990 Guile bindings for GnuTLS are available in the user's environment; when
4991 they are not available, an error is raised. @xref{Guile Preparations,
4992 how to install the GnuTLS bindings for Guile,, gnutls-guile,
4993 GnuTLS-Guile}, for more information.
4995 @command{guix download} verifies HTTPS server certificates by loading
4996 the certificates of X.509 authorities from the directory pointed to by
4997 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
4998 Certificates}), unless @option{--no-check-certificate} is used.
5000 The following options are available:
5003 @item --format=@var{fmt}
5005 Write the hash in the format specified by @var{fmt}. For more
5006 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5008 @item --no-check-certificate
5009 Do not validate the X.509 certificates of HTTPS servers.
5011 When using this option, you have @emph{absolutely no guarantee} that you
5012 are communicating with the authentic server responsible for the given
5013 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5015 @item --output=@var{file}
5016 @itemx -o @var{file}
5017 Save the downloaded file to @var{file} instead of adding it to the
5021 @node Invoking guix hash
5022 @section Invoking @command{guix hash}
5024 @cindex @command{guix hash}
5025 The @command{guix hash} command computes the SHA256 hash of a file.
5026 It is primarily a convenience tool for anyone contributing to the
5027 distribution: it computes the cryptographic hash of a file, which can be
5028 used in the definition of a package (@pxref{Defining Packages}).
5030 The general syntax is:
5033 guix hash @var{option} @var{file}
5036 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5037 hash of data read from standard input. @command{guix hash} has the
5042 @item --format=@var{fmt}
5044 Write the hash in the format specified by @var{fmt}.
5046 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5047 (@code{hex} and @code{hexadecimal} can be used as well).
5049 If the @option{--format} option is not specified, @command{guix hash}
5050 will output the hash in @code{nix-base32}. This representation is used
5051 in the definitions of packages.
5055 Compute the hash on @var{file} recursively.
5057 In this case, the hash is computed on an archive containing @var{file},
5058 including its children if it is a directory. Some of the metadata of
5059 @var{file} is part of the archive; for instance, when @var{file} is a
5060 regular file, the hash is different depending on whether @var{file} is
5061 executable or not. Metadata such as time stamps has no impact on the
5062 hash (@pxref{Invoking guix archive}).
5063 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5068 When combined with @option{--recursive}, exclude version control system
5069 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5072 As an example, here is how you would compute the hash of a Git checkout,
5073 which is useful when using the @code{git-fetch} method (@pxref{origin
5077 $ git clone http://example.org/foo.git
5083 @node Invoking guix import
5084 @section Invoking @command{guix import}
5086 @cindex importing packages
5087 @cindex package import
5088 @cindex package conversion
5089 @cindex Invoking @command{guix import}
5090 The @command{guix import} command is useful for people who would like to
5091 add a package to the distribution with as little work as
5092 possible---a legitimate demand. The command knows of a few
5093 repositories from which it can ``import'' package metadata. The result
5094 is a package definition, or a template thereof, in the format we know
5095 (@pxref{Defining Packages}).
5097 The general syntax is:
5100 guix import @var{importer} @var{options}@dots{}
5103 @var{importer} specifies the source from which to import package
5104 metadata, and @var{options} specifies a package identifier and other
5105 options specific to @var{importer}. Currently, the available
5110 Import metadata for the given GNU package. This provides a template
5111 for the latest version of that GNU package, including the hash of its
5112 source tarball, and its canonical synopsis and description.
5114 Additional information such as the package dependencies and its
5115 license needs to be figured out manually.
5117 For example, the following command returns a package definition for
5121 guix import gnu hello
5124 Specific command-line options are:
5127 @item --key-download=@var{policy}
5128 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5129 keys when verifying the package signature. @xref{Invoking guix
5130 refresh, @code{--key-download}}.
5135 Import metadata from the @uref{https://pypi.python.org/, Python Package
5136 Index}@footnote{This functionality requires Guile-JSON to be installed.
5137 @xref{Requirements}.}. Information is taken from the JSON-formatted
5138 description available at @code{pypi.python.org} and usually includes all
5139 the relevant information, including package dependencies. For maximum
5140 efficiency, it is recommended to install the @command{unzip} utility, so
5141 that the importer can unzip Python wheels and gather data from them.
5143 The command below imports metadata for the @code{itsdangerous} Python
5147 guix import pypi itsdangerous
5152 Import metadata from @uref{https://rubygems.org/,
5153 RubyGems}@footnote{This functionality requires Guile-JSON to be
5154 installed. @xref{Requirements}.}. Information is taken from the
5155 JSON-formatted description available at @code{rubygems.org} and includes
5156 most relevant information, including runtime dependencies. There are
5157 some caveats, however. The metadata doesn't distinguish between
5158 synopses and descriptions, so the same string is used for both fields.
5159 Additionally, the details of non-Ruby dependencies required to build
5160 native extensions is unavailable and left as an exercise to the
5163 The command below imports metadata for the @code{rails} Ruby package:
5166 guix import gem rails
5171 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5172 functionality requires Guile-JSON to be installed.
5173 @xref{Requirements}.}.
5174 Information is taken from the JSON-formatted metadata provided through
5175 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5176 relevant information, such as module dependencies. License information
5177 should be checked closely. If Perl is available in the store, then the
5178 @code{corelist} utility will be used to filter core modules out of the
5179 list of dependencies.
5181 The command command below imports metadata for the @code{Acme::Boolean}
5185 guix import cpan Acme::Boolean
5190 @cindex Bioconductor
5191 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5192 central repository for the @uref{http://r-project.org, GNU@tie{}R
5193 statistical and graphical environment}.
5195 Information is extracted from the @code{DESCRIPTION} file of the package.
5197 The command command below imports metadata for the @code{Cairo}
5201 guix import cran Cairo
5204 When @code{--recursive} is added, the importer will traverse the
5205 dependency graph of the given upstream package recursively and generate
5206 package expressions for all those packages that are not yet in Guix.
5208 When @code{--archive=bioconductor} is added, metadata is imported from
5209 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5210 packages for for the analysis and comprehension of high-throughput
5211 genomic data in bioinformatics.
5213 Information is extracted from the @code{DESCRIPTION} file of a package
5214 published on the web interface of the Bioconductor SVN repository.
5216 The command below imports metadata for the @code{GenomicRanges}
5220 guix import cran --archive=bioconductor GenomicRanges
5224 Import metadata from a local copy of the source of the
5225 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5226 relies on the @command{nix-instantiate} command of
5227 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5228 typically written in a mixture of Nix-language and Bash code. This
5229 command only imports the high-level package structure that is written in
5230 the Nix language. It normally includes all the basic fields of a
5233 When importing a GNU package, the synopsis and descriptions are replaced
5234 by their canonical upstream variant.
5236 Usually, you will first need to do:
5239 export NIX_REMOTE=daemon
5243 so that @command{nix-instantiate} does not try to open the Nix database.
5245 As an example, the command below imports the package definition of
5246 LibreOffice (more precisely, it imports the definition of the package
5247 bound to the @code{libreoffice} top-level attribute):
5250 guix import nix ~/path/to/nixpkgs libreoffice
5255 Import metadata from the Haskell community's central package archive
5256 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5257 Cabal files and includes all the relevant information, including package
5260 Specific command-line options are:
5265 Read a Cabal file from standard input.
5266 @item --no-test-dependencies
5268 Do not include dependencies required only by the test suites.
5269 @item --cabal-environment=@var{alist}
5270 @itemx -e @var{alist}
5271 @var{alist} is a Scheme alist defining the environment in which the
5272 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5273 @code{arch}, @code{impl} and a string representing the name of a flag.
5274 The value associated with a flag has to be either the symbol
5275 @code{true} or @code{false}. The value associated with other keys
5276 has to conform to the Cabal file format definition. The default value
5277 associated with the keys @code{os}, @code{arch} and @code{impl} is
5278 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5281 The command below imports metadata for the latest version of the
5282 @code{HTTP} Haskell package without including test dependencies and
5283 specifying the value of the flag @samp{network-uri} as @code{false}:
5286 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5289 A specific package version may optionally be specified by following the
5290 package name by an at-sign and a version number as in the following example:
5293 guix import hackage mtl@@2.1.3.1
5298 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5299 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5301 Specific command-line options are:
5304 @item --archive=@var{repo}
5305 @itemx -a @var{repo}
5306 @var{repo} identifies the archive repository from which to retrieve the
5307 information. Currently the supported repositories and their identifiers
5311 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5312 identifier. This is the default.
5314 Packages from @code{elpa.gnu.org} are signed with one of the keys
5315 contained in the GnuPG keyring at
5316 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5317 @code{emacs} package (@pxref{Package Installation, ELPA package
5318 signatures,, emacs, The GNU Emacs Manual}).
5321 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5322 @code{melpa-stable} identifier.
5325 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5332 Import metadata from the crates.io Rust package repository
5333 @uref{https://crates.io, crates.io}.
5336 The structure of the @command{guix import} code is modular. It would be
5337 useful to have more importers for other package formats, and your help
5338 is welcome here (@pxref{Contributing}).
5340 @node Invoking guix refresh
5341 @section Invoking @command{guix refresh}
5343 @cindex @command {guix refresh}
5344 The primary audience of the @command{guix refresh} command is developers
5345 of the GNU software distribution. By default, it reports any packages
5346 provided by the distribution that are outdated compared to the latest
5347 upstream version, like this:
5351 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5352 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5355 Alternately, one can specify packages to consider, in which case a
5356 warning is emitted for packages that lack an updater:
5359 $ guix refresh coreutils guile guile-ssh
5360 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5361 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5364 @command{guix refresh} browses the upstream repository of each package and determines
5365 the highest version number of the releases therein. The command
5366 knows how to update specific types of packages: GNU packages, ELPA
5367 packages, etc.---see the documentation for @option{--type} below. There
5368 are many packages, though, for which it lacks a method to determine
5369 whether a new upstream release is available. However, the mechanism is
5370 extensible, so feel free to get in touch with us to add a new method!
5372 When passed @code{--update}, it modifies distribution source files to
5373 update the version numbers and source tarball hashes of those package
5374 recipes (@pxref{Defining Packages}). This is achieved by downloading
5375 each package's latest source tarball and its associated OpenPGP
5376 signature, authenticating the downloaded tarball against its signature
5377 using @command{gpg}, and finally computing its hash. When the public
5378 key used to sign the tarball is missing from the user's keyring, an
5379 attempt is made to automatically retrieve it from a public key server;
5380 when this is successful, the key is added to the user's keyring; otherwise,
5381 @command{guix refresh} reports an error.
5383 The following options are supported:
5387 @item --expression=@var{expr}
5388 @itemx -e @var{expr}
5389 Consider the package @var{expr} evaluates to.
5391 This is useful to precisely refer to a package, as in this example:
5394 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
5397 This command lists the dependents of the ``final'' libc (essentially all
5402 Update distribution source files (package recipes) in place. This is
5403 usually run from a checkout of the Guix source tree (@pxref{Running
5404 Guix Before It Is Installed}):
5407 $ ./pre-inst-env guix refresh -s non-core -u
5410 @xref{Defining Packages}, for more information on package definitions.
5412 @item --select=[@var{subset}]
5413 @itemx -s @var{subset}
5414 Select all the packages in @var{subset}, one of @code{core} or
5417 The @code{core} subset refers to all the packages at the core of the
5418 distribution---i.e., packages that are used to build ``everything
5419 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
5420 changing one of these packages in the distribution entails a rebuild of
5421 all the others. Thus, such updates are an inconvenience to users in
5422 terms of build time or bandwidth used to achieve the upgrade.
5424 The @code{non-core} subset refers to the remaining packages. It is
5425 typically useful in cases where an update of the core packages would be
5428 @item --type=@var{updater}
5429 @itemx -t @var{updater}
5430 Select only packages handled by @var{updater} (may be a comma-separated
5431 list of updaters). Currently, @var{updater} may be one of:
5435 the updater for GNU packages;
5437 the updater for GNOME packages;
5439 the updater for KDE packages;
5441 the updater for X.org packages;
5443 the updater for packages hosted on kernel.org;
5445 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
5447 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
5449 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
5451 the updater for @uref{http://www.cpan.org/, CPAN} packages;
5453 the updater for @uref{https://pypi.python.org, PyPI} packages.
5455 the updater for @uref{https://rubygems.org, RubyGems} packages.
5457 the updater for @uref{https://github.com, GitHub} packages.
5459 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
5461 the updater for @uref{https://crates.io, Crates} packages.
5464 For instance, the following command only checks for updates of Emacs
5465 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
5468 $ guix refresh --type=elpa,cran
5469 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
5470 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
5475 In addition, @command{guix refresh} can be passed one or more package
5476 names, as in this example:
5479 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
5483 The command above specifically updates the @code{emacs} and
5484 @code{idutils} packages. The @code{--select} option would have no
5485 effect in this case.
5487 When considering whether to upgrade a package, it is sometimes
5488 convenient to know which packages would be affected by the upgrade and
5489 should be checked for compatibility. For this the following option may
5490 be used when passing @command{guix refresh} one or more package names:
5494 @item --list-updaters
5496 List available updaters and exit (see @option{--type} above.)
5498 For each updater, display the fraction of packages it covers; at the
5499 end, display the fraction of packages covered by all these updaters.
5501 @item --list-dependent
5503 List top-level dependent packages that would need to be rebuilt as a
5504 result of upgrading one or more packages.
5506 @xref{Invoking guix graph, the @code{reverse-package} type of
5507 @command{guix graph}}, for information on how to visualize the list of
5508 dependents of a package.
5512 Be aware that the @code{--list-dependent} option only
5513 @emph{approximates} the rebuilds that would be required as a result of
5514 an upgrade. More rebuilds might be required under some circumstances.
5517 $ guix refresh --list-dependent flex
5518 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
5519 hop-2.4.0 geiser-0.4 notmuch-0.18 mu-0.9.9.5 cflow-1.4 idutils-4.6 @dots{}
5522 The command above lists a set of packages that could be built to check
5523 for compatibility with an upgraded @code{flex} package.
5525 The following options can be used to customize GnuPG operation:
5529 @item --gpg=@var{command}
5530 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
5531 for in @code{$PATH}.
5533 @item --key-download=@var{policy}
5534 Handle missing OpenPGP keys according to @var{policy}, which may be one
5539 Always download missing OpenPGP keys from the key server, and add them
5540 to the user's GnuPG keyring.
5543 Never try to download missing OpenPGP keys. Instead just bail out.
5546 When a package signed with an unknown OpenPGP key is encountered, ask
5547 the user whether to download it or not. This is the default behavior.
5550 @item --key-server=@var{host}
5551 Use @var{host} as the OpenPGP key server when importing a public key.
5555 The @code{github} updater uses the
5556 @uref{https://developer.github.com/v3/, GitHub API} to query for new
5557 releases. When used repeatedly e.g. when refreshing all packages,
5558 GitHub will eventually refuse to answer any further API requests. By
5559 default 60 API requests per hour are allowed, and a full refresh on all
5560 GitHub packages in Guix requires more than this. Authentication with
5561 GitHub through the use of an API token alleviates these limits. To use
5562 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
5563 token procured from @uref{https://github.com/settings/tokens} or
5567 @node Invoking guix lint
5568 @section Invoking @command{guix lint}
5570 @cindex @command{guix lint}
5571 @cindex package, checking for errors
5572 The @command{guix lint} command is meant to help package developers avoid
5573 common errors and use a consistent style. It runs a number of checks on
5574 a given set of packages in order to find common mistakes in their
5575 definitions. Available @dfn{checkers} include (see
5576 @code{--list-checkers} for a complete list):
5581 Validate certain typographical and stylistic rules about package
5582 descriptions and synopses.
5584 @item inputs-should-be-native
5585 Identify inputs that should most likely be native inputs.
5590 @itemx source-file-name
5591 Probe @code{home-page} and @code{source} URLs and report those that are
5592 invalid. Suggest a @code{mirror://} URL when applicable. Check that
5593 the source file name is meaningful, e.g. is not
5594 just a version number or ``git-checkout'', without a declared
5595 @code{file-name} (@pxref{origin Reference}).
5598 @cindex security vulnerabilities
5599 @cindex CVE, Common Vulnerabilities and Exposures
5600 Report known vulnerabilities found in the Common Vulnerabilities and
5601 Exposures (CVE) databases of the current and past year
5602 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
5605 To view information about a particular vulnerability, visit pages such as:
5609 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
5611 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
5615 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
5616 @code{CVE-2015-7554}.
5618 Package developers can specify in package recipes the
5619 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
5620 name and version of the package when they differ from the name that Guix
5621 uses, as in this example:
5627 ;; CPE calls this package "grub2".
5628 (properties '((cpe-name . "grub2"))))
5632 Warn about obvious source code formatting issues: trailing white space,
5633 use of tabulations, etc.
5636 The general syntax is:
5639 guix lint @var{options} @var{package}@dots{}
5642 If no package is given on the command line, then all packages are checked.
5643 The @var{options} may be zero or more of the following:
5646 @item --list-checkers
5648 List and describe all the available checkers that will be run on packages
5653 Only enable the checkers specified in a comma-separated list using the
5654 names returned by @code{--list-checkers}.
5658 @node Invoking guix size
5659 @section Invoking @command{guix size}
5662 @cindex package size
5664 @cindex @command{guix size}
5665 The @command{guix size} command helps package developers profile the
5666 disk usage of packages. It is easy to overlook the impact of an
5667 additional dependency added to a package, or the impact of using a
5668 single output for a package that could easily be split (@pxref{Packages
5669 with Multiple Outputs}). Such are the typical issues that
5670 @command{guix size} can highlight.
5672 The command can be passed a package specification such as @code{gcc-4.8}
5673 or @code{guile:debug}, or a file name in the store. Consider this
5677 $ guix size coreutils
5678 store item total self
5679 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
5680 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
5681 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
5682 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
5683 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
5684 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
5688 The store items listed here constitute the @dfn{transitive closure} of
5689 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
5690 would be returned by:
5693 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
5696 Here the output shows three columns next to store items. The first column,
5697 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
5698 the store item---that is, its own size plus the size of all its
5699 dependencies. The next column, labeled ``self'', shows the size of the
5700 item itself. The last column shows the ratio of the size of the item
5701 itself to the space occupied by all the items listed here.
5703 In this example, we see that the closure of Coreutils weighs in at
5704 70@tie{}MiB, half of which is taken by libc. (That libc represents a
5705 large fraction of the closure is not a problem @i{per se} because it is
5706 always available on the system anyway.)
5708 When the package passed to @command{guix size} is available in the
5709 store, @command{guix size} queries the daemon to determine its
5710 dependencies, and measures its size in the store, similar to @command{du
5711 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
5714 When the given package is @emph{not} in the store, @command{guix size}
5715 reports information based on the available substitutes
5716 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
5717 store items that are not even on disk, only available remotely.
5719 You can also specify several package names:
5722 $ guix size coreutils grep sed bash
5723 store item total self
5724 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
5725 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
5726 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
5727 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
5733 In this example we see that the combination of the four packages takes
5734 102.3@tie{}MiB in total, which is much less than the sum of each closure
5735 since they have a lot of dependencies in common.
5737 The available options are:
5741 @item --substitute-urls=@var{urls}
5742 Use substitute information from @var{urls}.
5743 @xref{client-substitute-urls, the same option for @code{guix build}}.
5745 @item --map-file=@var{file}
5746 Write a graphical map of disk usage in PNG format to @var{file}.
5748 For the example above, the map looks like this:
5750 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
5751 produced by @command{guix size}}
5753 This option requires that
5754 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
5755 installed and visible in Guile's module search path. When that is not
5756 the case, @command{guix size} fails as it tries to load it.
5758 @item --system=@var{system}
5759 @itemx -s @var{system}
5760 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
5764 @node Invoking guix graph
5765 @section Invoking @command{guix graph}
5768 @cindex @command{guix graph}
5769 @cindex package dependencies
5770 Packages and their dependencies form a @dfn{graph}, specifically a
5771 directed acyclic graph (DAG). It can quickly become difficult to have a
5772 mental model of the package DAG, so the @command{guix graph} command
5773 provides a visual representation of the DAG. By default,
5774 @command{guix graph} emits a DAG representation in the input format of
5775 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
5776 directly to the @command{dot} command of Graphviz. It can also emit an
5777 HTML page with embedded JavaScript code to display a ``chord diagram''
5778 in a Web browser, using the @uref{https://d3js.org/, d3.js} library.
5779 The general syntax is:
5782 guix graph @var{options} @var{package}@dots{}
5785 For example, the following command generates a PDF file representing the
5786 package DAG for the GNU@tie{}Core Utilities, showing its build-time
5790 guix graph coreutils | dot -Tpdf > dag.pdf
5793 The output looks like this:
5795 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
5797 Nice little graph, no?
5799 But there is more than one graph! The one above is concise: it is the
5800 graph of package objects, omitting implicit inputs such as GCC, libc,
5801 grep, etc. It is often useful to have such a concise graph, but
5802 sometimes one may want to see more details. @command{guix graph} supports
5803 several types of graphs, allowing you to choose the level of detail:
5807 This is the default type used in the example above. It shows the DAG of
5808 package objects, excluding implicit dependencies. It is concise, but
5809 filters out many details.
5811 @item reverse-package
5812 This shows the @emph{reverse} DAG of packages. For example:
5815 guix graph --type=reverse-package ocaml
5818 ... yields the graph of packages that depend on OCaml.
5820 Note that for core packages this can yield huge graphs. If all you want
5821 is to know the number of packages that depend on a given package, use
5822 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
5823 @option{--list-dependent}}).
5826 This is the package DAG, @emph{including} implicit inputs.
5828 For instance, the following command:
5831 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
5834 ... yields this bigger graph:
5836 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
5838 At the bottom of the graph, we see all the implicit inputs of
5839 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
5841 Now, note that the dependencies of these implicit inputs---that is, the
5842 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
5843 here, for conciseness.
5846 Similar to @code{bag-emerged}, but this time including all the bootstrap
5849 @item bag-with-origins
5850 Similar to @code{bag}, but also showing origins and their dependencies.
5853 This is the most detailed representation: It shows the DAG of
5854 derivations (@pxref{Derivations}) and plain store items. Compared to
5855 the above representation, many additional nodes are visible, including
5856 build scripts, patches, Guile modules, etc.
5858 For this type of graph, it is also possible to pass a @file{.drv} file
5859 name instead of a package name, as in:
5862 guix graph -t derivation `guix system build -d my-config.scm`
5866 All the types above correspond to @emph{build-time dependencies}. The
5867 following graph type represents the @emph{run-time dependencies}:
5871 This is the graph of @dfn{references} of a package output, as returned
5872 by @command{guix gc --references} (@pxref{Invoking guix gc}).
5874 If the given package output is not available in the store, @command{guix
5875 graph} attempts to obtain dependency information from substitutes.
5877 Here you can also pass a store file name instead of a package name. For
5878 example, the command below produces the reference graph of your profile
5879 (which can be big!):
5882 guix graph -t references `readlink -f ~/.guix-profile`
5886 This is the graph of the @dfn{referrers} of a store item, as returned by
5887 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
5889 This relies exclusively on local information from your store. For
5890 instance, let us suppose that the current Inkscape is available in 10
5891 profiles on your machine; @command{guix graph -t referrers inkscape}
5892 will show a graph rooted at Inkscape and with those 10 profiles linked
5895 It can help determine what is preventing a store item from being garbage
5900 The available options are the following:
5903 @item --type=@var{type}
5904 @itemx -t @var{type}
5905 Produce a graph output of @var{type}, where @var{type} must be one of
5906 the values listed above.
5909 List the supported graph types.
5911 @item --backend=@var{backend}
5912 @itemx -b @var{backend}
5913 Produce a graph using the selected @var{backend}.
5915 @item --list-backends
5916 List the supported graph backends.
5918 Currently, the available backends are Graphviz and d3.js.
5920 @item --expression=@var{expr}
5921 @itemx -e @var{expr}
5922 Consider the package @var{expr} evaluates to.
5924 This is useful to precisely refer to a package, as in this example:
5927 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
5932 @node Invoking guix environment
5933 @section Invoking @command{guix environment}
5935 @cindex reproducible build environments
5936 @cindex development environments
5937 @cindex @command{guix environment}
5938 @cindex environment, package build environment
5939 The purpose of @command{guix environment} is to assist hackers in
5940 creating reproducible development environments without polluting their
5941 package profile. The @command{guix environment} tool takes one or more
5942 packages, builds all of their inputs, and creates a shell
5943 environment to use them.
5945 The general syntax is:
5948 guix environment @var{options} @var{package}@dots{}
5951 The following example spawns a new shell set up for the development of
5955 guix environment guile
5958 If the needed dependencies are not built yet, @command{guix environment}
5959 automatically builds them. The environment of the new shell is an augmented
5960 version of the environment that @command{guix environment} was run in.
5961 It contains the necessary search paths for building the given package
5962 added to the existing environment variables. To create a ``pure''
5963 environment, in which the original environment variables have been unset,
5964 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
5965 environment variables such as @code{PATH} in their @file{~/.bashrc}
5966 file. As a consequence, when @code{guix environment} launches it, Bash
5967 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
5968 environment variables. It is an error to define such environment
5969 variables in @file{.bashrc}; instead, they should be defined in
5970 @file{.bash_profile}, which is sourced only by log-in shells.
5971 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
5972 details on Bash start-up files.}.
5974 @vindex GUIX_ENVIRONMENT
5975 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
5976 variable in the shell it spawns; its value is the file name of the
5977 profile of this environment. This allows users to, say, define a
5978 specific prompt for development environments in their @file{.bashrc}
5979 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
5982 if [ -n "$GUIX_ENVIRONMENT" ]
5984 export PS1="\u@@\h \w [dev]\$ "
5989 ... or to browse the profile:
5992 $ ls "$GUIX_ENVIRONMENT/bin"
5995 Additionally, more than one package may be specified, in which case the
5996 union of the inputs for the given packages are used. For example, the
5997 command below spawns a shell where all of the dependencies of both Guile
5998 and Emacs are available:
6001 guix environment guile emacs
6004 Sometimes an interactive shell session is not desired. An arbitrary
6005 command may be invoked by placing the @code{--} token to separate the
6006 command from the rest of the arguments:
6009 guix environment guile -- make -j4
6012 In other situations, it is more convenient to specify the list of
6013 packages needed in the environment. For example, the following command
6014 runs @command{python} from an environment containing Python@tie{}2.7 and
6018 guix environment --ad-hoc python2-numpy python-2.7 -- python
6021 Furthermore, one might want the dependencies of a package and also some
6022 additional packages that are not build-time or runtime dependencies, but
6023 are useful when developing nonetheless. Because of this, the
6024 @code{--ad-hoc} flag is positional. Packages appearing before
6025 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6026 added to the environment. Packages appearing after are interpreted as
6027 packages that will be added to the environment directly. For example,
6028 the following command creates a Guix development environment that
6029 additionally includes Git and strace:
6032 guix environment guix --ad-hoc git strace
6035 Sometimes it is desirable to isolate the environment as much as
6036 possible, for maximal purity and reproducibility. In particular, when
6037 using Guix on a host distro that is not GuixSD, it is desirable to
6038 prevent access to @file{/usr/bin} and other system-wide resources from
6039 the development environment. For example, the following command spawns
6040 a Guile REPL in a ``container'' where only the store and the current
6041 working directory are mounted:
6044 guix environment --ad-hoc --container guile -- guile
6048 The @code{--container} option requires Linux-libre 3.19 or newer.
6051 The available options are summarized below.
6054 @item --root=@var{file}
6055 @itemx -r @var{file}
6056 @cindex persistent environment
6057 @cindex garbage collector root, for environments
6058 Make @var{file} a symlink to the profile for this environment, and
6059 register it as a garbage collector root.
6061 This is useful if you want to protect your environment from garbage
6062 collection, to make it ``persistent''.
6064 When this option is omitted, the environment is protected from garbage
6065 collection only for the duration of the @command{guix environment}
6066 session. This means that next time you recreate the same environment,
6067 you could have to rebuild or re-download packages.
6069 @item --expression=@var{expr}
6070 @itemx -e @var{expr}
6071 Create an environment for the package or list of packages that
6072 @var{expr} evaluates to.
6074 For example, running:
6077 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6080 starts a shell with the environment for this specific variant of the
6086 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6089 starts a shell with all the GuixSD base packages available.
6091 The above commands only the use default output of the given packages.
6092 To select other outputs, two element tuples can be specified:
6095 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6098 @item --load=@var{file}
6099 @itemx -l @var{file}
6100 Create an environment for the package or list of packages that the code
6101 within @var{file} evaluates to.
6103 As an example, @var{file} might contain a definition like this
6104 (@pxref{Defining Packages}):
6107 @verbatiminclude environment-gdb.scm
6111 Include all specified packages in the resulting environment, as if an
6112 @i{ad hoc} package were defined with them as inputs. This option is
6113 useful for quickly creating an environment without having to write a
6114 package expression to contain the desired inputs.
6116 For instance, the command:
6119 guix environment --ad-hoc guile guile-sdl -- guile
6122 runs @command{guile} in an environment where Guile and Guile-SDL are
6125 Note that this example implicitly asks for the default output of
6126 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6127 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6128 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6130 This option may be composed with the default behavior of @command{guix
6131 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6132 as packages whose dependencies will be added to the environment, the
6133 default behavior. Packages appearing after are interpreted as packages
6134 that will be added to the environment directly.
6137 Unset existing environment variables when building the new environment.
6138 This has the effect of creating an environment in which search paths
6139 only contain package inputs.
6141 @item --search-paths
6142 Display the environment variable definitions that make up the
6145 @item --system=@var{system}
6146 @itemx -s @var{system}
6147 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6152 Run @var{command} within an isolated container. The current working
6153 directory outside the container is mapped inside the container.
6154 Additionally, a dummy home directory is created that matches the current
6155 user's home directory, and @file{/etc/passwd} is configured accordingly.
6156 The spawned process runs as the current user outside the container, but
6157 has root privileges in the context of the container.
6161 For containers, share the network namespace with the host system.
6162 Containers created without this flag only have access to the loopback
6165 @item --expose=@var{source}[=@var{target}]
6166 For containers, expose the file system @var{source} from the host system
6167 as the read-only file system @var{target} within the container. If
6168 @var{target} is not specified, @var{source} is used as the target mount
6169 point in the container.
6171 The example below spawns a Guile REPL in a container in which the user's
6172 home directory is accessible read-only via the @file{/exchange}
6176 guix environment --container --expose=$HOME=/exchange guile -- guile
6179 @item --share=@var{source}[=@var{target}]
6180 For containers, share the file system @var{source} from the host system
6181 as the writable file system @var{target} within the container. If
6182 @var{target} is not specified, @var{source} is used as the target mount
6183 point in the container.
6185 The example below spawns a Guile REPL in a container in which the user's
6186 home directory is accessible for both reading and writing via the
6187 @file{/exchange} directory:
6190 guix environment --container --share=$HOME=/exchange guile -- guile
6194 It also supports all of the common build options that @command{guix
6195 build} supports (@pxref{Common Build Options}).
6197 @node Invoking guix publish
6198 @section Invoking @command{guix publish}
6200 @cindex @command{guix publish}
6201 The purpose of @command{guix publish} is to enable users to easily share
6202 their store with others, who can then use it as a substitute server
6203 (@pxref{Substitutes}).
6205 When @command{guix publish} runs, it spawns an HTTP server which allows
6206 anyone with network access to obtain substitutes from it. This means
6207 that any machine running Guix can also act as if it were a build farm,
6208 since the HTTP interface is compatible with Hydra, the software behind
6209 the @code{hydra.gnu.org} build farm.
6211 For security, each substitute is signed, allowing recipients to check
6212 their authenticity and integrity (@pxref{Substitutes}). Because
6213 @command{guix publish} uses the signing key of the system, which is only
6214 readable by the system administrator, it must be started as root; the
6215 @code{--user} option makes it drop root privileges early on.
6217 The signing key pair must be generated before @command{guix publish} is
6218 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6221 The general syntax is:
6224 guix publish @var{options}@dots{}
6227 Running @command{guix publish} without any additional arguments will
6228 spawn an HTTP server on port 8080:
6234 Once a publishing server has been authorized (@pxref{Invoking guix
6235 archive}), the daemon may download substitutes from it:
6238 guix-daemon --substitute-urls=http://example.org:8080
6241 As a bonus, @command{guix publish} also serves as a content-addressed
6242 mirror for source files referenced in @code{origin} records
6243 (@pxref{origin Reference}). For instance, assuming @command{guix
6244 publish} is running on @code{example.org}, the following URL returns the
6245 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6246 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6249 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6252 Obviously, these URLs only work for files that are in the store; in
6253 other cases, they return 404 (``Not Found'').
6255 The following options are available:
6258 @item --port=@var{port}
6259 @itemx -p @var{port}
6260 Listen for HTTP requests on @var{port}.
6262 @item --listen=@var{host}
6263 Listen on the network interface for @var{host}. The default is to
6264 accept connections from any interface.
6266 @item --user=@var{user}
6267 @itemx -u @var{user}
6268 Change privileges to @var{user} as soon as possible---i.e., once the
6269 server socket is open and the signing key has been read.
6271 @item --compression[=@var{level}]
6272 @itemx -C [@var{level}]
6273 Compress data using the given @var{level}. When @var{level} is zero,
6274 disable compression. The range 1 to 9 corresponds to different gzip
6275 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6278 Compression occurs on the fly and the compressed streams are not
6279 cached. Thus, to reduce load on the machine that runs @command{guix
6280 publish}, it may be a good idea to choose a low compression level, or to
6281 run @command{guix publish} behind a caching proxy.
6283 @item --ttl=@var{ttl}
6284 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6285 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6286 days, @code{1m} means 1 month, and so on.
6288 This allows the user's Guix to keep substitute information in cache for
6289 @var{ttl}. However, note that @code{guix publish} does not itself
6290 guarantee that the store items it provides will indeed remain available
6291 for as long as @var{ttl}.
6293 @item --repl[=@var{port}]
6294 @itemx -r [@var{port}]
6295 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
6296 Reference Manual}) on @var{port} (37146 by default). This is used
6297 primarily for debugging a running @command{guix publish} server.
6300 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
6301 add a call to @code{guix-publish-service} in the @code{services} field
6302 of the @code{operating-system} declaration (@pxref{guix-publish-service,
6303 @code{guix-publish-service}}).
6305 If you are instead running Guix on a ``foreign distro'', follow these
6310 If your host distro uses the systemd init system:
6313 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
6314 /etc/systemd/system/
6315 # systemctl start guix-publish && systemctl enable guix-publish
6319 If your host distro uses the Upstart init system:
6322 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
6323 # start guix-publish
6327 Otherwise, proceed similarly with your distro's init system.
6330 @node Invoking guix challenge
6331 @section Invoking @command{guix challenge}
6333 @cindex reproducible builds
6334 @cindex verifiable builds
6335 @cindex @command{guix challenge}
6337 Do the binaries provided by this server really correspond to the source
6338 code it claims to build? Is a package build process deterministic?
6339 These are the questions the @command{guix challenge} command attempts to
6342 The former is obviously an important question: Before using a substitute
6343 server (@pxref{Substitutes}), one had better @emph{verify} that it
6344 provides the right binaries, and thus @emph{challenge} it. The latter
6345 is what enables the former: If package builds are deterministic, then
6346 independent builds of the package should yield the exact same result,
6347 bit for bit; if a server provides a binary different from the one
6348 obtained locally, it may be either corrupt or malicious.
6350 We know that the hash that shows up in @file{/gnu/store} file names is
6351 the hash of all the inputs of the process that built the file or
6352 directory---compilers, libraries, build scripts,
6353 etc. (@pxref{Introduction}). Assuming deterministic build processes,
6354 one store file name should map to exactly one build output.
6355 @command{guix challenge} checks whether there is, indeed, a single
6356 mapping by comparing the build outputs of several independent builds of
6357 any given store item.
6359 The command output looks like this:
6362 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
6363 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
6364 updating list of substitutes from 'https://guix.example.org'... 100.0%
6365 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
6366 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6367 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6368 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
6369 /gnu/store/@dots{}-git-2.5.0 contents differ:
6370 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
6371 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
6372 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
6373 /gnu/store/@dots{}-pius-2.1.1 contents differ:
6374 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6375 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6376 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
6380 In this example, @command{guix challenge} first scans the store to
6381 determine the set of locally-built derivations---as opposed to store
6382 items that were downloaded from a substitute server---and then queries
6383 all the substitute servers. It then reports those store items for which
6384 the servers obtained a result different from the local build.
6386 @cindex non-determinism, in package builds
6387 As an example, @code{guix.example.org} always gets a different answer.
6388 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
6389 case of Git. This might indicate that the build process of Git is
6390 non-deterministic, meaning that its output varies as a function of
6391 various things that Guix does not fully control, in spite of building
6392 packages in isolated environments (@pxref{Features}). Most common
6393 sources of non-determinism include the addition of timestamps in build
6394 results, the inclusion of random numbers, and directory listings sorted
6395 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
6398 To find out what is wrong with this Git binary, we can do something along
6399 these lines (@pxref{Invoking guix archive}):
6402 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
6403 | guix archive -x /tmp/git
6404 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
6407 This command shows the difference between the files resulting from the
6408 local build, and the files resulting from the build on
6409 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
6410 diffutils, Comparing and Merging Files}). The @command{diff} command
6411 works great for text files. When binary files differ, a better option
6412 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
6413 visualize differences for all kinds of files.
6415 Once you have done that work, you can tell whether the differences are due
6416 to a non-deterministic build process or to a malicious server. We try
6417 hard to remove sources of non-determinism in packages to make it easier
6418 to verify substitutes, but of course, this is a process that
6419 involves not just Guix, but a large part of the free software community.
6420 In the meantime, @command{guix challenge} is one tool to help address
6423 If you are writing packages for Guix, you are encouraged to check
6424 whether @code{hydra.gnu.org} and other substitute servers obtain the
6425 same build result as you did with:
6428 $ guix challenge @var{package}
6432 where @var{package} is a package specification such as
6433 @code{guile@@2.0} or @code{glibc:debug}.
6435 The general syntax is:
6438 guix challenge @var{options} [@var{packages}@dots{}]
6441 When a difference is found between the hash of a locally-built item and
6442 that of a server-provided substitute, or among substitutes provided by
6443 different servers, the command displays it as in the example above and
6444 its exit code is 2 (other non-zero exit codes denote other kinds of
6447 The one option that matters is:
6451 @item --substitute-urls=@var{urls}
6452 Consider @var{urls} the whitespace-separated list of substitute source
6457 Show details about matches (identical contents) in addition to
6458 information about mismatches.
6462 @node Invoking guix copy
6463 @section Invoking @command{guix copy}
6465 @cindex copy, of store items, over SSH
6466 @cindex SSH, copy of store items
6467 @cindex sharing store items across machines
6468 @cindex transferring store items across machines
6469 The @command{guix copy} command copies items from the store of one
6470 machine to that of another machine over a secure shell (SSH)
6471 connection@footnote{This command is available only when Guile-SSH was
6472 found. @xref{Requirements}, for details.}. For example, the following
6473 command copies the @code{coreutils} package, the user's profile, and all
6474 their dependencies over to @var{host}, logged in as @var{user}:
6477 guix copy --to=@var{user}@@@var{host} \
6478 coreutils `readlink -f ~/.guix-profile`
6481 If some of the items to be copied are already present on @var{host},
6482 they are not actually sent.
6484 The command below retrieves @code{libreoffice} and @code{gimp} from
6485 @var{host}, assuming they are available there:
6488 guix copy --from=@var{host} libreoffice gimp
6491 The SSH connection is established using the Guile-SSH client, which is
6492 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
6493 @file{~/.ssh/config}, and uses the SSH agent for authentication.
6495 The key used to sign items that are sent must be accepted by the remote
6496 machine. Likewise, the key used by the remote machine to sign items you
6497 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
6498 own daemon. @xref{Invoking guix archive}, for more information about
6499 store item authentication.
6501 The general syntax is:
6504 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
6507 You must always specify one of the following options:
6510 @item --to=@var{spec}
6511 @itemx --from=@var{spec}
6512 Specify the host to send to or receive from. @var{spec} must be an SSH
6513 spec such as @code{example.org}, @code{charlie@@example.org}, or
6514 @code{charlie@@example.org:2222}.
6517 The @var{items} can be either package names, such as @code{gimp}, or
6518 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
6520 When specifying the name of a package to send, it is first built if
6521 needed, unless @option{--dry-run} was specified. Common build options
6522 are supported (@pxref{Common Build Options}).
6525 @node Invoking guix container
6526 @section Invoking @command{guix container}
6528 @cindex @command{guix container}
6530 As of version @value{VERSION}, this tool is experimental. The interface
6531 is subject to radical change in the future.
6534 The purpose of @command{guix container} is to manipulate processes
6535 running within an isolated environment, commonly known as a
6536 ``container'', typically created by the @command{guix environment}
6537 (@pxref{Invoking guix environment}) and @command{guix system container}
6538 (@pxref{Invoking guix system}) commands.
6540 The general syntax is:
6543 guix container @var{action} @var{options}@dots{}
6546 @var{action} specifies the operation to perform with a container, and
6547 @var{options} specifies the context-specific arguments for the action.
6549 The following actions are available:
6553 Execute a command within the context of a running container.
6558 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
6561 @var{pid} specifies the process ID of the running container.
6562 @var{program} specifies an executable file name within the root file
6563 system of the container. @var{arguments} are the additional options that
6564 will be passed to @var{program}.
6566 The following command launches an interactive login shell inside a
6567 GuixSD container, started by @command{guix system container}, and whose
6571 guix container exec 9001 /run/current-system/profile/bin/bash --login
6574 Note that the @var{pid} cannot be the parent process of a container. It
6575 must be PID 1 of the container or one of its child processes.
6579 @c *********************************************************************
6580 @node GNU Distribution
6581 @chapter GNU Distribution
6583 @cindex Guix System Distribution
6585 Guix comes with a distribution of the GNU system consisting entirely of
6586 free software@footnote{The term ``free'' here refers to the
6587 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
6588 users of that software}.}. The
6589 distribution can be installed on its own (@pxref{System Installation}),
6590 but it is also possible to install Guix as a package manager on top of
6591 an installed GNU/Linux system (@pxref{Installation}). To distinguish
6592 between the two, we refer to the standalone distribution as the Guix
6593 System Distribution, or GuixSD.
6595 The distribution provides core GNU packages such as GNU libc, GCC, and
6596 Binutils, as well as many GNU and non-GNU applications. The complete
6597 list of available packages can be browsed
6598 @url{http://www.gnu.org/software/guix/packages,on-line} or by
6599 running @command{guix package} (@pxref{Invoking guix package}):
6602 guix package --list-available
6605 Our goal is to provide a practical 100% free software distribution of
6606 Linux-based and other variants of GNU, with a focus on the promotion and
6607 tight integration of GNU components, and an emphasis on programs and
6608 tools that help users exert that freedom.
6610 Packages are currently available on the following platforms:
6615 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
6618 Intel 32-bit architecture (IA32), Linux-Libre kernel;
6621 ARMv7-A architecture with hard float, Thumb-2 and NEON,
6622 using the EABI hard-float application binary interface (ABI),
6623 and Linux-Libre kernel.
6625 @item mips64el-linux
6626 little-endian 64-bit MIPS processors, specifically the Loongson series,
6627 n32 ABI, and Linux-Libre kernel.
6631 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
6634 For information on porting to other architectures or kernels,
6638 * System Installation:: Installing the whole operating system.
6639 * System Configuration:: Configuring the operating system.
6640 * Installing Debugging Files:: Feeding the debugger.
6641 * Security Updates:: Deploying security fixes quickly.
6642 * Package Modules:: Packages from the programmer's viewpoint.
6643 * Packaging Guidelines:: Growing the distribution.
6644 * Bootstrapping:: GNU/Linux built from scratch.
6645 * Porting:: Targeting another platform or kernel.
6648 Building this distribution is a cooperative effort, and you are invited
6649 to join! @xref{Contributing}, for information about how you can help.
6651 @node System Installation
6652 @section System Installation
6654 @cindex installing GuixSD
6655 @cindex Guix System Distribution
6656 This section explains how to install the Guix System Distribution (GuixSD)
6657 on a machine. The Guix package manager can
6658 also be installed on top of a running GNU/Linux system,
6659 @pxref{Installation}.
6663 @c This paragraph is for people reading this from tty2 of the
6664 @c installation image.
6665 You are reading this documentation with an Info reader. For details on
6666 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
6667 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
6668 Info}. Hit @kbd{l} afterwards to come back here.
6670 Alternately, run @command{info info} in another tty to keep the manual
6676 * Limitations:: What you can expect.
6677 * Hardware Considerations:: Supported hardware.
6678 * USB Stick Installation:: Preparing the installation medium.
6679 * Preparing for Installation:: Networking, partitioning, etc.
6680 * Proceeding with the Installation:: The real thing.
6681 * Installing GuixSD in a VM:: GuixSD playground.
6682 * Building the Installation Image:: How this comes to be.
6686 @subsection Limitations
6688 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
6689 not production-ready. It may contain bugs and lack important
6690 features. Thus, if you are looking for a stable production system that
6691 respects your freedom as a computer user, a good solution at this point
6692 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
6693 the more established GNU/Linux distributions}. We hope you can soon switch
6694 to the GuixSD without fear, of course. In the meantime, you can
6695 also keep using your distribution and try out the package manager on top
6696 of it (@pxref{Installation}).
6698 Before you proceed with the installation, be aware of the following
6699 noteworthy limitations applicable to version @value{VERSION}:
6703 The installation process does not include a graphical user interface and
6704 requires familiarity with GNU/Linux (see the following subsections to
6705 get a feel of what that means.)
6708 Support for the Logical Volume Manager (LVM) is missing.
6711 Few system services are currently supported out-of-the-box
6715 More than 4,000 packages are available, but you may
6716 occasionally find that a useful package is missing.
6719 GNOME, Xfce, and Enlightenment are available (@pxref{Desktop Services}),
6720 as well as a number of X11 window managers. However, some graphical
6721 applications may be missing, as well as KDE.
6724 You have been warned! But more than a disclaimer, this is an invitation
6725 to report issues (and success stories!), and to join us in improving it.
6726 @xref{Contributing}, for more info.
6729 @node Hardware Considerations
6730 @subsection Hardware Considerations
6732 @cindex hardware support on GuixSD
6733 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
6734 builds around the kernel Linux-libre, which means that only hardware for
6735 which free software drivers and firmware exist is supported. Nowadays,
6736 a wide range of off-the-shelf hardware is supported on
6737 GNU/Linux-libre---from keyboards to graphics cards to scanners and
6738 Ethernet controllers. Unfortunately, there are still areas where
6739 hardware vendors deny users control over their own computing, and such
6740 hardware is not supported on GuixSD.
6742 @cindex WiFi, hardware support
6743 One of the main areas where free drivers or firmware are lacking is WiFi
6744 devices. WiFi devices known to work include those using Atheros chips
6745 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
6746 driver, and those using Broadcom/AirForce chips (BCM43xx with
6747 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
6748 Linux-libre driver. Free firmware exists for both and is available
6749 out-of-the-box on GuixSD, as part of @var{%base-firmware}
6750 (@pxref{operating-system Reference, @code{firmware}}).
6752 @cindex RYF, Respects Your Freedom
6753 The @uref{https://www.fsf.org/, Free Software Foundation} runs
6754 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
6755 certification program for hardware products that respect your freedom
6756 and your privacy and ensure that you have control over your device. We
6757 encourage you to check the list of RYF-certified devices.
6759 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
6760 web site. It contains a catalog of hardware devices with information
6761 about their support in GNU/Linux.
6764 @node USB Stick Installation
6765 @subsection USB Stick Installation
6767 An installation image for USB sticks can be downloaded from
6768 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
6769 where @var{system} is one of:
6773 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
6776 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
6779 @c start duplication of authentication part from ``Binary Installation''
6780 Make sure to download the associated @file{.sig} file and to verify the
6781 authenticity of the image against it, along these lines:
6784 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
6785 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
6788 If that command fails because you do not have the required public key,
6789 then run this command to import it:
6792 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
6796 and rerun the @code{gpg --verify} command.
6799 This image contains a single partition with the tools necessary for an
6800 installation. It is meant to be copied @emph{as is} to a large-enough
6803 To copy the image to a USB stick, follow these steps:
6807 Decompress the image using the @command{xz} command:
6810 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
6814 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
6815 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
6816 copy the image with:
6819 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
6822 Access to @file{/dev/sdX} usually requires root privileges.
6825 Once this is done, you should be able to reboot the system and boot from
6826 the USB stick. The latter usually requires you to get in the BIOS' boot
6827 menu, where you can choose to boot from the USB stick.
6829 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
6830 GuixSD in a virtual machine (VM).
6832 @node Preparing for Installation
6833 @subsection Preparing for Installation
6835 Once you have successfully booted the image on the USB stick, you should
6836 end up with a root prompt. Several console TTYs are configured and can
6837 be used to run commands as root. TTY2 shows this documentation,
6838 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
6839 Stand-alone GNU Info}). The installation system runs the GPM mouse
6840 daemon, which allows you to select text with the left mouse button and
6841 to paste it with the middle button.
6844 Installation requires access to the Internet so that any missing
6845 dependencies of your system configuration can be downloaded. See the
6846 ``Networking'' section below.
6849 The installation system includes many common tools needed for this task.
6850 But it is also a full-blown GuixSD system, which means that you can
6851 install additional packages, should you need it, using @command{guix
6852 package} (@pxref{Invoking guix package}).
6854 @subsubsection Keyboard Layout
6856 @cindex keyboard layout
6857 The installation image uses the US qwerty keyboard layout. If you want
6858 to change it, you can use the @command{loadkeys} command. For example,
6859 the following command selects the Dvorak keyboard layout:
6865 See the files under @file{/run/current-system/profile/share/keymaps} for
6866 a list of available keyboard layouts. Run @command{man loadkeys} for
6869 @subsubsection Networking
6871 Run the following command see what your network interfaces are called:
6878 @dots{} or, using the GNU/Linux-specific @command{ip} command:
6884 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
6885 Wired interfaces have a name starting with @samp{e}; for example, the
6886 interface corresponding to the first on-board Ethernet controller is
6887 called @samp{eno1}. Wireless interfaces have a name starting with
6888 @samp{w}, like @samp{w1p2s0}.
6891 @item Wired connection
6892 To configure a wired network run the following command, substituting
6893 @var{interface} with the name of the wired interface you want to use.
6896 ifconfig @var{interface} up
6899 @item Wireless connection
6902 To configure wireless networking, you can create a configuration file
6903 for the @command{wpa_supplicant} configuration tool (its location is not
6904 important) using one of the available text editors such as
6908 zile wpa_supplicant.conf
6911 As an example, the following stanza can go to this file and will work
6912 for many wireless networks, provided you give the actual SSID and
6913 passphrase for the network you are connecting to:
6917 ssid="@var{my-ssid}"
6919 psk="the network's secret passphrase"
6923 Start the wireless service and run it in the background with the
6924 following command (substitute @var{interface} with the name of the
6925 network interface you want to use):
6928 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
6931 Run @command{man wpa_supplicant} for more information.
6935 At this point, you need to acquire an IP address. On a network where IP
6936 addresses are automatically assigned @i{via} DHCP, you can run:
6939 dhclient -v @var{interface}
6942 Try to ping a server to see if networking is up and running:
6948 Setting up network access is almost always a requirement because the
6949 image does not contain all the software and tools that may be needed.
6951 @subsubsection Disk Partitioning
6953 Unless this has already been done, the next step is to partition, and
6954 then format the target partition(s).
6956 The installation image includes several partitioning tools, including
6957 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
6958 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
6959 the partition layout you want:
6965 Once you are done partitioning the target hard disk drive, you have to
6966 create a file system on the relevant partition(s)@footnote{Currently
6967 GuixSD only supports ext4 and btrfs file systems. In particular, code
6968 that reads partition UUIDs and labels only works for these file system
6971 Preferably, assign partitions a label so that you can easily and
6972 reliably refer to them in @code{file-system} declarations (@pxref{File
6973 Systems}). This is typically done using the @code{-L} option of
6974 @command{mkfs.ext4} and related commands. So, assuming the target root
6975 partition lives at @file{/dev/sda1}, a file system with the label
6976 @code{my-root} can be created with:
6979 mkfs.ext4 -L my-root /dev/sda1
6982 @cindex encrypted disk
6983 If you are instead planning to encrypt the root partition, you can use
6984 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
6985 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
6986 @code{man cryptsetup}} for more information.) Assuming you want to
6987 store the root partition on @file{/dev/sda1}, the command sequence would
6988 be along these lines:
6991 cryptsetup luksFormat /dev/sda1
6992 cryptsetup open --type luks /dev/sda1 my-partition
6993 mkfs.ext4 -L my-root /dev/mapper/my-partition
6996 Once that is done, mount the target root partition under @file{/mnt}
6997 with a command like (again, assuming @code{my-root} is the label of the
7001 mount LABEL=my-root /mnt
7004 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7005 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7006 sure to initialize them with @command{mkswap}. Assuming you have one
7007 swap partition on @file{/dev/sda2}, you would run:
7014 @node Proceeding with the Installation
7015 @subsection Proceeding with the Installation
7017 With the target partitions ready and the target root mounted on
7018 @file{/mnt}, we're ready to go. First, run:
7021 herd start cow-store /mnt
7024 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7025 during the installation phase are written to the target disk on @file{/mnt}
7026 rather than kept in memory. This is necessary because the first phase of
7027 the @command{guix system init} command (see below) entails downloads or
7028 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7030 Next, you have to edit a file and
7031 provide the declaration of the operating system to be installed. To
7032 that end, the installation system comes with three text editors: GNU nano
7033 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7034 nvi (a clone of the original BSD @command{vi} editor).
7035 We strongly recommend storing that file on the target root file system, say,
7036 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7037 configuration file once you have rebooted into the newly-installed system.
7039 @xref{Using the Configuration System}, for an overview of the
7040 configuration file. The example configurations discussed in that
7041 section are available under @file{/etc/configuration} in the
7042 installation image. Thus, to get started with a system configuration
7043 providing a graphical display server (a ``desktop'' system), you can run
7044 something along these lines:
7048 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7049 # zile /mnt/etc/config.scm
7052 You should pay attention to what your configuration file contains, and
7057 Make sure the @code{grub-configuration} form refers to the device you
7058 want to install GRUB on.
7061 Be sure that your partition labels match the value of their respective
7062 @code{device} fields in your @code{file-system} configuration, assuming
7063 your @code{file-system} configuration sets the value of @code{title} to
7067 If there are encrypted or RAID partitions, make sure to add a
7068 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7071 Once you are done preparing the configuration file, the new system must
7072 be initialized (remember that the target root file system is mounted
7076 guix system init /mnt/etc/config.scm /mnt
7080 This copies all the necessary files and installs GRUB on
7081 @file{/dev/sdX}, unless you pass the @option{--no-grub} option. For
7082 more information, @pxref{Invoking guix system}. This command may trigger
7083 downloads or builds of missing packages, which can take some time.
7085 Once that command has completed---and hopefully succeeded!---you can run
7086 @command{reboot} and boot into the new system. The @code{root} password
7087 in the new system is initially empty; other users' passwords need to be
7088 initialized by running the @command{passwd} command as @code{root},
7089 unless your configuration specifies otherwise
7090 (@pxref{user-account-password, user account passwords}).
7092 @cindex upgrading GuixSD
7093 From then on, you can update GuixSD whenever you want by running
7094 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7095 then running @command{guix system reconfigure} to build a new system
7096 generation with the latest packages and services (@pxref{Invoking guix
7097 system}). We recommend doing that regularly so that your system
7098 includes the latest security updates (@pxref{Security Updates}).
7100 Join us on @code{#guix} on the Freenode IRC network or on
7101 @file{guix-devel@@gnu.org} to share your experience---good or not so
7104 @node Installing GuixSD in a VM
7105 @subsection Installing GuixSD in a Virtual Machine
7107 @cindex virtual machine, GuixSD installation
7108 If you'd like to install GuixSD in a virtual machine (VM) rather than on
7109 your beloved machine, this section is for you.
7111 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7112 disk image, follow these steps:
7116 First, retrieve the GuixSD installation image as described previously
7117 (@pxref{USB Stick Installation}).
7120 Create a disk image that will hold the installed system. To make a
7121 qcow2-formatted disk image, use the @command{qemu-img} command:
7124 qemu-img create -f qcow2 guixsd.img 5G
7127 This will create a 5GB file.
7130 Boot the USB installation image in an VM:
7133 qemu-system-x86_64 -m 1024 -smp 1 \
7134 -net default -net nic,model=virtio -boot menu=on \
7135 -drive file=guixsd.img \
7136 -drive file=guixsd-usb-install-@value{VERSION}.@var{system}
7139 In the VM console, quickly press the @kbd{F12} key to enter the boot
7140 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7144 You're now root in the VM, proceed with the installation process.
7145 @xref{Preparing for Installation}, and follow the instructions.
7148 Once installation is complete, you can boot the system that's on your
7149 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
7152 @node Building the Installation Image
7153 @subsection Building the Installation Image
7155 @cindex installation image
7156 The installation image described above was built using the @command{guix
7157 system} command, specifically:
7159 @c FIXME: 1G is too much; see <http://bugs.gnu.org/23077>.
7161 guix system disk-image --image-size=1G gnu/system/install.scm
7164 Have a look at @file{gnu/system/install.scm} in the source tree,
7165 and see also @ref{Invoking guix system} for more information
7166 about the installation image.
7168 @node System Configuration
7169 @section System Configuration
7171 @cindex system configuration
7172 The Guix System Distribution supports a consistent whole-system configuration
7173 mechanism. By that we mean that all aspects of the global system
7174 configuration---such as the available system services, timezone and
7175 locale settings, user accounts---are declared in a single place. Such
7176 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
7178 One of the advantages of putting all the system configuration under the
7179 control of Guix is that it supports transactional system upgrades, and
7180 makes it possible to roll back to a previous system instantiation,
7181 should something go wrong with the new one (@pxref{Features}). Another
7182 advantage is that it makes it easy to replicate the exact same configuration
7183 across different machines, or at different points in time, without
7184 having to resort to additional administration tools layered on top of
7185 the own tools of the system.
7186 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
7188 This section describes this mechanism. First we focus on the system
7189 administrator's viewpoint---explaining how the system is configured and
7190 instantiated. Then we show how this mechanism can be extended, for
7191 instance to support new system services.
7194 * Using the Configuration System:: Customizing your GNU system.
7195 * operating-system Reference:: Detail of operating-system declarations.
7196 * File Systems:: Configuring file system mounts.
7197 * Mapped Devices:: Block device extra processing.
7198 * User Accounts:: Specifying user accounts.
7199 * Locales:: Language and cultural convention settings.
7200 * Services:: Specifying system services.
7201 * Setuid Programs:: Programs running with root privileges.
7202 * X.509 Certificates:: Authenticating HTTPS servers.
7203 * Name Service Switch:: Configuring libc's name service switch.
7204 * Initial RAM Disk:: Linux-Libre bootstrapping.
7205 * GRUB Configuration:: Configuring the boot loader.
7206 * Invoking guix system:: Instantiating a system configuration.
7207 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
7208 * Defining Services:: Adding new service definitions.
7211 @node Using the Configuration System
7212 @subsection Using the Configuration System
7214 The operating system is configured by providing an
7215 @code{operating-system} declaration in a file that can then be passed to
7216 the @command{guix system} command (@pxref{Invoking guix system}). A
7217 simple setup, with the default system services, the default Linux-Libre
7218 kernel, initial RAM disk, and boot loader looks like this:
7220 @findex operating-system
7222 @include os-config-bare-bones.texi
7225 This example should be self-describing. Some of the fields defined
7226 above, such as @code{host-name} and @code{bootloader}, are mandatory.
7227 Others, such as @code{packages} and @code{services}, can be omitted, in
7228 which case they get a default value.
7230 Below we discuss the effect of some of the most important fields
7231 (@pxref{operating-system Reference}, for details about all the available
7232 fields), and how to @dfn{instantiate} the operating system using
7233 @command{guix system}.
7235 @unnumberedsubsubsec Globally-Visible Packages
7237 @vindex %base-packages
7238 The @code{packages} field lists packages that will be globally visible
7239 on the system, for all user accounts---i.e., in every user's @code{PATH}
7240 environment variable---in addition to the per-user profiles
7241 (@pxref{Invoking guix package}). The @var{%base-packages} variable
7242 provides all the tools one would expect for basic user and administrator
7243 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
7244 the GNU Zile lightweight text editor, @command{find}, @command{grep},
7245 etc. The example above adds tcpdump to those, taken from the @code{(gnu
7246 packages admin)} module (@pxref{Package Modules}).
7248 @findex specification->package
7249 Referring to packages by variable name, like @var{tcpdump} above, has
7250 the advantage of being unambiguous; it also allows typos and such to be
7251 diagnosed right away as ``unbound variables''. The downside is that one
7252 needs to know which module defines which package, and to augment the
7253 @code{use-package-modules} line accordingly. To avoid that, one can use
7254 the @code{specification->package} procedure of the @code{(gnu packages)}
7255 module, which returns the best package for a given name or name and
7259 (use-modules (gnu packages))
7263 (packages (append (map specification->package
7264 '("tcpdump" "htop" "gnupg@@2.0"))
7268 @unnumberedsubsubsec System Services
7271 @vindex %base-services
7272 The @code{services} field lists @dfn{system services} to be made
7273 available when the system starts (@pxref{Services}).
7274 The @code{operating-system} declaration above specifies that, in
7275 addition to the basic services, we want the @command{lshd} secure shell
7276 daemon listening on port 2222 (@pxref{Networking Services,
7277 @code{lsh-service}}). Under the hood,
7278 @code{lsh-service} arranges so that @code{lshd} is started with the
7279 right command-line options, possibly with supporting configuration files
7280 generated as needed (@pxref{Defining Services}).
7282 @cindex customization, of services
7283 @findex modify-services
7284 Occasionally, instead of using the base services as is, you will want to
7285 customize them. To do this, use @code{modify-services} (@pxref{Service
7286 Reference, @code{modify-services}}) to modify the list.
7288 For example, suppose you want to modify @code{guix-daemon} and Mingetty
7289 (the console log-in) in the @var{%base-services} list (@pxref{Base
7290 Services, @code{%base-services}}). To do that, you can write the
7291 following in your operating system declaration:
7294 (define %my-services
7295 ;; My very own list of services.
7296 (modify-services %base-services
7297 (guix-service-type config =>
7300 (use-substitutes? #f)
7301 (extra-options '("--gc-keep-derivations"))))
7302 (mingetty-service-type config =>
7303 (mingetty-configuration
7304 (inherit config)))))
7308 (services %my-services))
7311 This changes the configuration---i.e., the service parameters---of the
7312 @code{guix-service-type} instance, and that of all the
7313 @code{mingetty-service-type} instances in the @var{%base-services} list.
7314 Observe how this is accomplished: first, we arrange for the original
7315 configuration to be bound to the identifier @code{config} in the
7316 @var{body}, and then we write the @var{body} so that it evaluates to the
7317 desired configuration. In particular, notice how we use @code{inherit}
7318 to create a new configuration which has the same values as the old
7319 configuration, but with a few modifications.
7321 @cindex encrypted disk
7322 The configuration for a typical ``desktop'' usage, with an encrypted
7323 root partition, the X11 display
7324 server, GNOME and Xfce (users can choose which of these desktop
7325 environments to use at the log-in screen by pressing @kbd{F1}), network
7326 management, power management, and more, would look like this:
7329 @include os-config-desktop.texi
7332 A graphical environment with a choice of lightweight window managers
7333 instead of full-blown desktop environments would look like this:
7336 @include os-config-lightweight-desktop.texi
7339 @xref{Desktop Services}, for the exact list of services provided by
7340 @var{%desktop-services}. @xref{X.509 Certificates}, for background
7341 information about the @code{nss-certs} package that is used here.
7343 Again, @var{%desktop-services} is just a list of service objects. If
7344 you want to remove services from there, you can do so using the
7345 procedures for list filtering (@pxref{SRFI-1 Filtering and
7346 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
7347 following expression returns a list that contains all the services in
7348 @var{%desktop-services} minus the Avahi service:
7351 (remove (lambda (service)
7352 (eq? (service-kind service) avahi-service-type))
7356 @unnumberedsubsubsec Instantiating the System
7358 Assuming the @code{operating-system} declaration
7359 is stored in the @file{my-system-config.scm}
7360 file, the @command{guix system reconfigure my-system-config.scm} command
7361 instantiates that configuration, and makes it the default GRUB boot
7362 entry (@pxref{Invoking guix system}).
7364 The normal way to change the system configuration is by updating this
7365 file and re-running @command{guix system reconfigure}. One should never
7366 have to touch files in @file{/etc} or to run commands that modify the
7367 system state such as @command{useradd} or @command{grub-install}. In
7368 fact, you must avoid that since that would not only void your warranty
7369 but also prevent you from rolling back to previous versions of your
7370 system, should you ever need to.
7372 @cindex roll-back, of the operating system
7373 Speaking of roll-back, each time you run @command{guix system
7374 reconfigure}, a new @dfn{generation} of the system is created---without
7375 modifying or deleting previous generations. Old system generations get
7376 an entry in the GRUB boot menu, allowing you to boot them in case
7377 something went wrong with the latest generation. Reassuring, no? The
7378 @command{guix system list-generations} command lists the system
7379 generations available on disk. It is also possible to roll back the
7380 system via the commands @command{guix system roll-back} and
7381 @command{guix system switch-generation}.
7383 Although the command @command{guix system reconfigure} will not modify
7384 previous generations, must take care when the current generation is not
7385 the latest (e.g., after invoking @command{guix system roll-back}), since
7386 the operation might overwrite a later generation (@pxref{Invoking guix
7389 @unnumberedsubsubsec The Programming Interface
7391 At the Scheme level, the bulk of an @code{operating-system} declaration
7392 is instantiated with the following monadic procedure (@pxref{The Store
7395 @deffn {Monadic Procedure} operating-system-derivation os
7396 Return a derivation that builds @var{os}, an @code{operating-system}
7397 object (@pxref{Derivations}).
7399 The output of the derivation is a single directory that refers to all
7400 the packages, configuration files, and other supporting files needed to
7401 instantiate @var{os}.
7404 This procedure is provided by the @code{(gnu system)} module. Along
7405 with @code{(gnu services)} (@pxref{Services}), this module contains the
7406 guts of GuixSD. Make sure to visit it!
7409 @node operating-system Reference
7410 @subsection @code{operating-system} Reference
7412 This section summarizes all the options available in
7413 @code{operating-system} declarations (@pxref{Using the Configuration
7416 @deftp {Data Type} operating-system
7417 This is the data type representing an operating system configuration.
7418 By that, we mean all the global system configuration, not per-user
7419 configuration (@pxref{Using the Configuration System}).
7422 @item @code{kernel} (default: @var{linux-libre})
7423 The package object of the operating system kernel to use@footnote{Currently
7424 only the Linux-libre kernel is supported. In the future, it will be
7425 possible to use the GNU@tie{}Hurd.}.
7427 @item @code{kernel-arguments} (default: @code{'()})
7428 List of strings or gexps representing additional arguments to pass on
7429 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
7431 @item @code{bootloader}
7432 The system bootloader configuration object. @xref{GRUB Configuration}.
7434 @item @code{initrd} (default: @code{base-initrd})
7436 @cindex initial RAM disk
7437 A two-argument monadic procedure that returns an initial RAM disk for
7438 the Linux kernel. @xref{Initial RAM Disk}.
7440 @item @code{firmware} (default: @var{%base-firmware})
7442 List of firmware packages loadable by the operating system kernel.
7444 The default includes firmware needed for Atheros- and Broadcom-based
7445 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
7446 respectively). @xref{Hardware Considerations}, for more info on
7449 @item @code{host-name}
7452 @item @code{hosts-file}
7454 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
7455 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
7456 Reference Manual}). The default is a file with entries for
7457 @code{localhost} and @var{host-name}.
7459 @item @code{mapped-devices} (default: @code{'()})
7460 A list of mapped devices. @xref{Mapped Devices}.
7462 @item @code{file-systems}
7463 A list of file systems. @xref{File Systems}.
7465 @item @code{swap-devices} (default: @code{'()})
7466 @cindex swap devices
7467 A list of strings identifying devices to be used for ``swap space''
7468 (@pxref{Memory Concepts,,, libc, The GNU C Library Reference Manual}).
7469 For example, @code{'("/dev/sda3")}.
7471 @item @code{users} (default: @code{%base-user-accounts})
7472 @itemx @code{groups} (default: @var{%base-groups})
7473 List of user accounts and groups. @xref{User Accounts}.
7475 @item @code{skeletons} (default: @code{(default-skeletons)})
7476 A list target file name/file-like object tuples (@pxref{G-Expressions,
7477 file-like objects}). These are the skeleton files that will be added to
7478 the home directory of newly-created user accounts.
7480 For instance, a valid value may look like this:
7483 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
7484 (".guile" ,(plain-file "guile"
7485 "(use-modules (ice-9 readline))
7486 (activate-readline)")))
7489 @item @code{issue} (default: @var{%default-issue})
7490 A string denoting the contents of the @file{/etc/issue} file, which is
7491 displayed when users log in on a text console.
7493 @item @code{packages} (default: @var{%base-packages})
7494 The set of packages installed in the global profile, which is accessible
7495 at @file{/run/current-system/profile}.
7497 The default set includes core utilities and it is good practice to
7498 install non-core utilities in user profiles (@pxref{Invoking guix
7501 @item @code{timezone}
7502 A timezone identifying string---e.g., @code{"Europe/Paris"}.
7504 You can run the @command{tzselect} command to find out which timezone
7505 string corresponds to your region. Choosing an invalid timezone name
7506 causes @command{guix system} to fail.
7508 @item @code{locale} (default: @code{"en_US.utf8"})
7509 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
7510 Library Reference Manual}). @xref{Locales}, for more information.
7512 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
7513 The list of locale definitions to be compiled and that may be used at
7514 run time. @xref{Locales}.
7516 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
7517 The list of GNU@tie{}libc packages whose locale data and tools are used
7518 to build the locale definitions. @xref{Locales}, for compatibility
7519 considerations that justify this option.
7521 @item @code{name-service-switch} (default: @var{%default-nss})
7522 Configuration of the libc name service switch (NSS)---a
7523 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
7526 @item @code{services} (default: @var{%base-services})
7527 A list of service objects denoting system services. @xref{Services}.
7529 @item @code{pam-services} (default: @code{(base-pam-services)})
7531 @cindex pluggable authentication modules
7532 Linux @dfn{pluggable authentication module} (PAM) services.
7533 @c FIXME: Add xref to PAM services section.
7535 @item @code{setuid-programs} (default: @var{%setuid-programs})
7536 List of string-valued G-expressions denoting setuid programs.
7537 @xref{Setuid Programs}.
7539 @item @code{sudoers-file} (default: @var{%sudoers-specification})
7540 @cindex sudoers file
7541 The contents of the @file{/etc/sudoers} file as a file-like object
7542 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
7544 This file specifies which users can use the @command{sudo} command, what
7545 they are allowed to do, and what privileges they may gain. The default
7546 is that only @code{root} and members of the @code{wheel} group may use
7553 @subsection File Systems
7555 The list of file systems to be mounted is specified in the
7556 @code{file-systems} field of the operating system declaration
7557 (@pxref{Using the Configuration System}). Each file system is declared
7558 using the @code{file-system} form, like this:
7562 (mount-point "/home")
7563 (device "/dev/sda3")
7567 As usual, some of the fields are mandatory---those shown in the example
7568 above---while others can be omitted. These are described below.
7570 @deftp {Data Type} file-system
7571 Objects of this type represent file systems to be mounted. They
7572 contain the following members:
7576 This is a string specifying the type of the file system---e.g.,
7579 @item @code{mount-point}
7580 This designates the place where the file system is to be mounted.
7583 This names the ``source'' of the file system. By default it is the name
7584 of a node under @file{/dev}, but its meaning depends on the @code{title}
7585 field described below.
7587 @item @code{title} (default: @code{'device})
7588 This is a symbol that specifies how the @code{device} field is to be
7591 When it is the symbol @code{device}, then the @code{device} field is
7592 interpreted as a file name; when it is @code{label}, then @code{device}
7593 is interpreted as a partition label name; when it is @code{uuid},
7594 @code{device} is interpreted as a partition unique identifier (UUID).
7596 UUIDs may be converted from their string representation (as shown by the
7597 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
7598 @code{uuid} form expects 16-byte UUIDs as defined in
7599 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
7600 form of UUID used by the ext2 family of file systems and others, but it
7601 is different from ``UUIDs'' found in FAT file systems, for instance.},
7606 (mount-point "/home")
7609 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
7612 The @code{label} and @code{uuid} options offer a way to refer to disk
7613 partitions without having to hard-code their actual device
7614 name@footnote{Note that, while it is tempting to use
7615 @file{/dev/disk/by-uuid} and similar device names to achieve the same
7616 result, this is not recommended: These special device nodes are created
7617 by the udev daemon and may be unavailable at the time the device is
7620 However, when the source of a file system is a mapped device (@pxref{Mapped
7621 Devices}), its @code{device} field @emph{must} refer to the mapped
7622 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
7623 @code{title} must be set to @code{'device}. This is required so that
7624 the system knows that mounting the file system depends on having the
7625 corresponding device mapping established.
7627 @item @code{flags} (default: @code{'()})
7628 This is a list of symbols denoting mount flags. Recognized flags
7629 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
7630 access to special files), @code{no-suid} (ignore setuid and setgid
7631 bits), and @code{no-exec} (disallow program execution.)
7633 @item @code{options} (default: @code{#f})
7634 This is either @code{#f}, or a string denoting mount options.
7636 @item @code{mount?} (default: @code{#t})
7637 This value indicates whether to automatically mount the file system when
7638 the system is brought up. When set to @code{#f}, the file system gets
7639 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
7640 is not automatically mounted.
7642 @item @code{needed-for-boot?} (default: @code{#f})
7643 This Boolean value indicates whether the file system is needed when
7644 booting. If that is true, then the file system is mounted when the
7645 initial RAM disk (initrd) is loaded. This is always the case, for
7646 instance, for the root file system.
7648 @item @code{check?} (default: @code{#t})
7649 This Boolean indicates whether the file system needs to be checked for
7650 errors before being mounted.
7652 @item @code{create-mount-point?} (default: @code{#f})
7653 When true, the mount point is created if it does not exist yet.
7655 @item @code{dependencies} (default: @code{'()})
7656 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
7657 representing file systems that must be mounted or mapped devices that
7658 must be opened before (and unmounted or closed after) this one.
7660 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
7661 a dependency of @file{/sys/fs/cgroup/cpu} and
7662 @file{/sys/fs/cgroup/memory}.
7664 Another example is a file system that depends on a mapped device, for
7665 example for an encrypted partition (@pxref{Mapped Devices}).
7669 The @code{(gnu system file-systems)} exports the following useful
7672 @defvr {Scheme Variable} %base-file-systems
7673 These are essential file systems that are required on normal systems,
7674 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
7675 below.) Operating system declarations should always contain at least
7679 @defvr {Scheme Variable} %pseudo-terminal-file-system
7680 This is the file system to be mounted as @file{/dev/pts}. It supports
7681 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
7682 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
7683 Manual}). Pseudo-terminals are used by terminal emulators such as
7687 @defvr {Scheme Variable} %shared-memory-file-system
7688 This file system is mounted as @file{/dev/shm} and is used to support
7689 memory sharing across processes (@pxref{Memory-mapped I/O,
7690 @code{shm_open},, libc, The GNU C Library Reference Manual}).
7693 @defvr {Scheme Variable} %immutable-store
7694 This file system performs a read-only ``bind mount'' of
7695 @file{/gnu/store}, making it read-only for all the users including
7696 @code{root}. This prevents against accidental modification by software
7697 running as @code{root} or by system administrators.
7699 The daemon itself is still able to write to the store: it remounts it
7700 read-write in its own ``name space.''
7703 @defvr {Scheme Variable} %binary-format-file-system
7704 The @code{binfmt_misc} file system, which allows handling of arbitrary
7705 executable file types to be delegated to user space. This requires the
7706 @code{binfmt.ko} kernel module to be loaded.
7709 @defvr {Scheme Variable} %fuse-control-file-system
7710 The @code{fusectl} file system, which allows unprivileged users to mount
7711 and unmount user-space FUSE file systems. This requires the
7712 @code{fuse.ko} kernel module to be loaded.
7715 @node Mapped Devices
7716 @subsection Mapped Devices
7718 @cindex device mapping
7719 @cindex mapped devices
7720 The Linux kernel has a notion of @dfn{device mapping}: a block device,
7721 such as a hard disk partition, can be @dfn{mapped} into another device,
7722 usually in @code{/dev/mapper/},
7723 with additional processing over the data that flows through
7724 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
7725 concept of a ``mapped device'' and that of a file system: both boil down
7726 to @emph{translating} input/output operations made on a file to
7727 operations on its backing store. Thus, the Hurd implements mapped
7728 devices, like file systems, using the generic @dfn{translator} mechanism
7729 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
7730 typical example is encryption device mapping: all writes to the mapped
7731 device are encrypted, and all reads are deciphered, transparently.
7732 Guix extends this notion by considering any device or set of devices that
7733 are @dfn{transformed} in some way to create a new device; for instance,
7734 RAID devices are obtained by @dfn{assembling} several other devices, such
7735 as hard disks or partitions, into a new one that behaves as one partition.
7736 Other examples, not yet implemented, are LVM logical volumes.
7738 Mapped devices are declared using the @code{mapped-device} form,
7739 defined as follows; for examples, see below.
7741 @deftp {Data Type} mapped-device
7742 Objects of this type represent device mappings that will be made when
7743 the system boots up.
7747 This is either a string specifying the name of the block device to be mapped,
7748 such as @code{"/dev/sda3"}, or a list of such strings when several devices
7749 need to be assembled for creating a new one.
7752 This string specifies the name of the resulting mapped device. For
7753 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
7754 specifying @code{"my-partition"} leads to the creation of
7755 the @code{"/dev/mapper/my-partition"} device.
7756 For RAID devices of type @code{raid-device-mapping}, the full device name
7757 such as @code{"/dev/md0"} needs to be given.
7760 This must be a @code{mapped-device-kind} object, which specifies how
7761 @var{source} is mapped to @var{target}.
7765 @defvr {Scheme Variable} luks-device-mapping
7766 This defines LUKS block device encryption using the @command{cryptsetup}
7767 command from the package with the same name. It relies on the
7768 @code{dm-crypt} Linux kernel module.
7771 @defvr {Scheme Variable} raid-device-mapping
7772 This defines a RAID device, which is assembled using the @code{mdadm}
7773 command from the package with the same name. It requires a Linux kernel
7774 module for the appropriate RAID level to be loaded, such as @code{raid456}
7775 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
7778 @cindex disk encryption
7780 The following example specifies a mapping from @file{/dev/sda3} to
7781 @file{/dev/mapper/home} using LUKS---the
7782 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
7783 standard mechanism for disk encryption.
7784 The @file{/dev/mapper/home}
7785 device can then be used as the @code{device} of a @code{file-system}
7786 declaration (@pxref{File Systems}).
7790 (source "/dev/sda3")
7792 (type luks-device-mapping))
7795 Alternatively, to become independent of device numbering, one may obtain
7796 the LUKS UUID (@dfn{unique identifier}) of the source device by a
7800 cryptsetup luksUUID /dev/sda3
7803 and use it as follows:
7807 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
7809 (type luks-device-mapping))
7812 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
7813 may be declared as follows:
7817 (source (list "/dev/sda1" "/dev/sdb1"))
7819 (type raid-device-mapping))
7822 The @file{/dev/md0} device can then be used as the @code{device} of a
7823 @code{file-system} declaration (@pxref{File Systems}).
7824 Note that the RAID level need not be given; it is chosen during the
7825 initial creation and formatting of the RAID device and is determined
7826 automatically later.
7830 @subsection User Accounts
7834 @cindex user accounts
7835 User accounts and groups are entirely managed through the
7836 @code{operating-system} declaration. They are specified with the
7837 @code{user-account} and @code{user-group} forms:
7843 (supplementary-groups '("wheel" ;allow use of sudo, etc.
7845 "video" ;video devices such as webcams
7846 "cdrom")) ;the good ol' CD-ROM
7847 (comment "Bob's sister")
7848 (home-directory "/home/alice"))
7851 When booting or upon completion of @command{guix system reconfigure},
7852 the system ensures that only the user accounts and groups specified in
7853 the @code{operating-system} declaration exist, and with the specified
7854 properties. Thus, account or group creations or modifications made by
7855 directly invoking commands such as @command{useradd} are lost upon
7856 reconfiguration or reboot. This ensures that the system remains exactly
7859 @deftp {Data Type} user-account
7860 Objects of this type represent user accounts. The following members may
7865 The name of the user account.
7869 This is the name (a string) or identifier (a number) of the user group
7870 this account belongs to.
7872 @item @code{supplementary-groups} (default: @code{'()})
7873 Optionally, this can be defined as a list of group names that this
7876 @item @code{uid} (default: @code{#f})
7877 This is the user ID for this account (a number), or @code{#f}. In the
7878 latter case, a number is automatically chosen by the system when the
7881 @item @code{comment} (default: @code{""})
7882 A comment about the account, such as the account owner's full name.
7884 @item @code{home-directory}
7885 This is the name of the home directory for the account.
7887 @item @code{create-home-directory?} (default: @code{#t})
7888 Indicates whether the home directory of this account should be created
7889 if it does not exist yet.
7891 @item @code{shell} (default: Bash)
7892 This is a G-expression denoting the file name of a program to be used as
7893 the shell (@pxref{G-Expressions}).
7895 @item @code{system?} (default: @code{#f})
7896 This Boolean value indicates whether the account is a ``system''
7897 account. System accounts are sometimes treated specially; for instance,
7898 graphical login managers do not list them.
7900 @anchor{user-account-password}
7901 @item @code{password} (default: @code{#f})
7902 You would normally leave this field to @code{#f}, initialize user
7903 passwords as @code{root} with the @command{passwd} command, and then let
7904 users change it with @command{passwd}. Passwords set with
7905 @command{passwd} are of course preserved across reboot and
7908 If you @emph{do} want to have a preset password for an account, then
7909 this field must contain the encrypted password, as a string.
7910 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
7911 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
7912 Manual}, for information on Guile's @code{crypt} procedure.
7918 User group declarations are even simpler:
7921 (user-group (name "students"))
7924 @deftp {Data Type} user-group
7925 This type is for, well, user groups. There are just a few fields:
7929 The name of the group.
7931 @item @code{id} (default: @code{#f})
7932 The group identifier (a number). If @code{#f}, a new number is
7933 automatically allocated when the group is created.
7935 @item @code{system?} (default: @code{#f})
7936 This Boolean value indicates whether the group is a ``system'' group.
7937 System groups have low numerical IDs.
7939 @item @code{password} (default: @code{#f})
7940 What, user groups can have a password? Well, apparently yes. Unless
7941 @code{#f}, this field specifies the password of the group.
7946 For convenience, a variable lists all the basic user groups one may
7949 @defvr {Scheme Variable} %base-groups
7950 This is the list of basic user groups that users and/or packages expect
7951 to be present on the system. This includes groups such as ``root'',
7952 ``wheel'', and ``users'', as well as groups used to control access to
7953 specific devices such as ``audio'', ``disk'', and ``cdrom''.
7956 @defvr {Scheme Variable} %base-user-accounts
7957 This is the list of basic system accounts that programs may expect to
7958 find on a GNU/Linux system, such as the ``nobody'' account.
7960 Note that the ``root'' account is not included here. It is a
7961 special-case and is automatically added whether or not it is specified.
7968 A @dfn{locale} defines cultural conventions for a particular language
7969 and region of the world (@pxref{Locales,,, libc, The GNU C Library
7970 Reference Manual}). Each locale has a name that typically has the form
7971 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
7972 @code{fr_LU.utf8} designates the locale for the French language, with
7973 cultural conventions from Luxembourg, and using the UTF-8 encoding.
7975 @cindex locale definition
7976 Usually, you will want to specify the default locale for the machine
7977 using the @code{locale} field of the @code{operating-system} declaration
7978 (@pxref{operating-system Reference, @code{locale}}).
7980 The selected locale is automatically added to the @dfn{locale
7981 definitions} known to the system if needed, with its codeset inferred
7982 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
7983 @code{UTF-8} codeset. Additional locale definitions can be specified in
7984 the @code{locale-definitions} slot of @code{operating-system}---this is
7985 useful, for instance, if the codeset could not be inferred from the
7986 locale name. The default set of locale definitions includes some widely
7987 used locales, but not all the available locales, in order to save space.
7989 For instance, to add the North Frisian locale for Germany, the value of
7993 (cons (locale-definition
7994 (name "fy_DE.utf8") (source "fy_DE"))
7995 %default-locale-definitions)
7998 Likewise, to save space, one might want @code{locale-definitions} to
7999 list only the locales that are actually used, as in:
8002 (list (locale-definition
8003 (name "ja_JP.eucjp") (source "ja_JP")
8004 (charset "EUC-JP")))
8008 The compiled locale definitions are available at
8009 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8010 version, which is the default location where the GNU@tie{}libc provided
8011 by Guix looks for locale data. This can be overridden using the
8012 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8013 @code{LOCPATH} and locale packages}).
8015 The @code{locale-definition} form is provided by the @code{(gnu system
8016 locale)} module. Details are given below.
8018 @deftp {Data Type} locale-definition
8019 This is the data type of a locale definition.
8024 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8025 Reference Manual}, for more information on locale names.
8028 The name of the source for that locale. This is typically the
8029 @code{@var{language}_@var{territory}} part of the locale name.
8031 @item @code{charset} (default: @code{"UTF-8"})
8032 The ``character set'' or ``code set'' for that locale,
8033 @uref{http://www.iana.org/assignments/character-sets, as defined by
8039 @defvr {Scheme Variable} %default-locale-definitions
8040 A list of commonly used UTF-8 locales, used as the default
8041 value of the @code{locale-definitions} field of @code{operating-system}
8045 @cindex normalized codeset in locale names
8046 These locale definitions use the @dfn{normalized codeset} for the part
8047 that follows the dot in the name (@pxref{Using gettextized software,
8048 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8049 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8053 @subsubsection Locale Data Compatibility Considerations
8055 @cindex incompatibility, of locale data
8056 @code{operating-system} declarations provide a @code{locale-libcs} field
8057 to specify the GNU@tie{}libc packages that are used to compile locale
8058 declarations (@pxref{operating-system Reference}). ``Why would I
8059 care?'', you may ask. Well, it turns out that the binary format of
8060 locale data is occasionally incompatible from one libc version to
8063 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8064 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8065 For instance, a program linked against libc version 2.21 is unable to
8066 read locale data produced with libc 2.22; worse, that program
8067 @emph{aborts} instead of simply ignoring the incompatible locale
8068 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8069 the incompatible locale data, which is already an improvement.}.
8070 Similarly, a program linked against libc 2.22 can read most, but not
8071 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8072 data is incompatible); thus calls to @code{setlocale} may fail, but
8073 programs will not abort.
8075 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8076 choose whether and when to upgrade software in their profiles, and might
8077 be using a libc version different from the one the system administrator
8078 used to build the system-wide locale data.
8080 Fortunately, unprivileged users can also install their own locale data
8081 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8082 @code{GUIX_LOCPATH} and locale packages}).
8084 Still, it is best if the system-wide locale data at
8085 @file{/run/current-system/locale} is built for all the libc versions
8086 actually in use on the system, so that all the programs can access
8087 it---this is especially crucial on a multi-user system. To do that, the
8088 administrator can specify several libc packages in the
8089 @code{locale-libcs} field of @code{operating-system}:
8092 (use-package-modules base)
8096 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8099 This example would lead to a system containing locale definitions for
8100 both libc 2.21 and the current version of libc in
8101 @file{/run/current-system/locale}.
8105 @subsection Services
8107 @cindex system services
8108 An important part of preparing an @code{operating-system} declaration is
8109 listing @dfn{system services} and their configuration (@pxref{Using the
8110 Configuration System}). System services are typically daemons launched
8111 when the system boots, or other actions needed at that time---e.g.,
8112 configuring network access.
8114 GuixSD has a broad definition of ``service'' (@pxref{Service
8115 Composition}), but many services are managed by the GNU@tie{}Shepherd
8116 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8117 command allows you to list the available services, show their status,
8118 start and stop them, or do other specific operations (@pxref{Jump
8119 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8125 The above command, run as @code{root}, lists the currently defined
8126 services. The @command{herd doc} command shows a synopsis of the given
8131 Run libc's name service cache daemon (nscd).
8134 The @command{start}, @command{stop}, and @command{restart} sub-commands
8135 have the effect you would expect. For instance, the commands below stop
8136 the nscd service and restart the Xorg display server:
8140 Service nscd has been stopped.
8141 # herd restart xorg-server
8142 Service xorg-server has been stopped.
8143 Service xorg-server has been started.
8146 The following sections document the available services, starting with
8147 the core services, that may be used in an @code{operating-system}
8151 * Base Services:: Essential system services.
8152 * Scheduled Job Execution:: The mcron service.
8153 * Log Rotation:: The rottlog service.
8154 * Networking Services:: Network setup, SSH daemon, etc.
8155 * X Window:: Graphical display.
8156 * Printing Services:: Local and remote printer support.
8157 * Desktop Services:: D-Bus and desktop services.
8158 * Database Services:: SQL databases.
8159 * Mail Services:: IMAP, POP3, SMTP, and all that.
8160 * Messaging Services:: Messaging services.
8161 * Kerberos Services:: Kerberos services.
8162 * Web Services:: Web servers.
8163 * VPN Services:: VPN daemons.
8164 * Network File System:: NFS related services.
8165 * Continuous Integration:: The Cuirass service.
8166 * Miscellaneous Services:: Other services.
8170 @subsubsection Base Services
8172 The @code{(gnu services base)} module provides definitions for the basic
8173 services that one expects from the system. The services exported by
8174 this module are listed below.
8176 @defvr {Scheme Variable} %base-services
8177 This variable contains a list of basic services (@pxref{Service Types
8178 and Services}, for more information on service objects) one would
8179 expect from the system: a login service (mingetty) on each tty, syslogd,
8180 the libc name service cache daemon (nscd), the udev device manager, and
8183 This is the default value of the @code{services} field of
8184 @code{operating-system} declarations. Usually, when customizing a
8185 system, you will want to append services to @var{%base-services}, like
8189 (cons* (avahi-service) (lsh-service) %base-services)
8193 @deffn {Scheme Procedure} host-name-service @var{name}
8194 Return a service that sets the host name to @var{name}.
8197 @deffn {Scheme Procedure} login-service @var{config}
8198 Return a service to run login according to @var{config}, a
8199 @code{<login-configuration>} object, which specifies the message of the day,
8203 @deftp {Data Type} login-configuration
8204 This is the data type representing the configuration of login.
8209 @cindex message of the day
8210 A file-like object containing the ``message of the day''.
8212 @item @code{allow-empty-passwords?} (default: @code{#t})
8213 Allow empty passwords by default so that first-time users can log in when
8214 the 'root' account has just been created.
8219 @deffn {Scheme Procedure} mingetty-service @var{config}
8220 Return a service to run mingetty according to @var{config}, a
8221 @code{<mingetty-configuration>} object, which specifies the tty to run, among
8225 @deftp {Data Type} mingetty-configuration
8226 This is the data type representing the configuration of Mingetty, which
8227 implements console log-in.
8232 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
8234 @item @code{auto-login} (default: @code{#f})
8235 When true, this field must be a string denoting the user name under
8236 which the system automatically logs in. When it is @code{#f}, a
8237 user name and password must be entered to log in.
8239 @item @code{login-program} (default: @code{#f})
8240 This must be either @code{#f}, in which case the default log-in program
8241 is used (@command{login} from the Shadow tool suite), or a gexp denoting
8242 the name of the log-in program.
8244 @item @code{login-pause?} (default: @code{#f})
8245 When set to @code{#t} in conjunction with @var{auto-login}, the user
8246 will have to press a key before the log-in shell is launched.
8248 @item @code{mingetty} (default: @var{mingetty})
8249 The Mingetty package to use.
8254 @deffn {Scheme Procedure} kmscon-service-type @var{config}
8255 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
8256 according to @var{config}, a @code{<kmscon-configuration>} object, which
8257 specifies the tty to run, among other things.
8260 @deftp {Data Type} kmscon-configuration
8261 This is the data type representing the configuration of Kmscon, which
8262 implements console log-in.
8266 @item @code{virtual-terminal}
8267 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
8269 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
8270 A gexp denoting the name of the log-in program. The default log-in program is
8271 @command{login} from the Shadow tool suite.
8273 @item @code{login-arguments} (default: @code{'("-p")})
8274 A list of arguments to pass to @command{login}.
8276 @item @code{hardware-acceleration?} (default: #f)
8277 Whether to use hardware acceleration.
8279 @item @code{kmscon} (default: @var{kmscon})
8280 The Kmscon package to use.
8285 @cindex name service cache daemon
8287 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
8288 [#:name-services '()]
8289 Return a service that runs the libc name service cache daemon (nscd) with the
8290 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
8291 Service Switch}, for an example.
8294 @defvr {Scheme Variable} %nscd-default-configuration
8295 This is the default @code{<nscd-configuration>} value (see below) used
8296 by @code{nscd-service}. It uses the caches defined by
8297 @var{%nscd-default-caches}; see below.
8300 @deftp {Data Type} nscd-configuration
8301 This is the data type representing the name service cache daemon (nscd)
8306 @item @code{name-services} (default: @code{'()})
8307 List of packages denoting @dfn{name services} that must be visible to
8308 the nscd---e.g., @code{(list @var{nss-mdns})}.
8310 @item @code{glibc} (default: @var{glibc})
8311 Package object denoting the GNU C Library providing the @command{nscd}
8314 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
8315 Name of the nscd log file. This is where debugging output goes when
8316 @code{debug-level} is strictly positive.
8318 @item @code{debug-level} (default: @code{0})
8319 Integer denoting the debugging levels. Higher numbers mean that more
8320 debugging output is logged.
8322 @item @code{caches} (default: @var{%nscd-default-caches})
8323 List of @code{<nscd-cache>} objects denoting things to be cached; see
8329 @deftp {Data Type} nscd-cache
8330 Data type representing a cache database of nscd and its parameters.
8334 @item @code{database}
8335 This is a symbol representing the name of the database to be cached.
8336 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
8337 @code{services}, which designate the corresponding NSS database
8338 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
8340 @item @code{positive-time-to-live}
8341 @itemx @code{negative-time-to-live} (default: @code{20})
8342 A number representing the number of seconds during which a positive or
8343 negative lookup result remains in cache.
8345 @item @code{check-files?} (default: @code{#t})
8346 Whether to check for updates of the files corresponding to
8349 For instance, when @var{database} is @code{hosts}, setting this flag
8350 instructs nscd to check for updates in @file{/etc/hosts} and to take
8353 @item @code{persistent?} (default: @code{#t})
8354 Whether the cache should be stored persistently on disk.
8356 @item @code{shared?} (default: @code{#t})
8357 Whether the cache should be shared among users.
8359 @item @code{max-database-size} (default: 32@tie{}MiB)
8360 Maximum size in bytes of the database cache.
8362 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
8363 @c settings, so leave them out.
8368 @defvr {Scheme Variable} %nscd-default-caches
8369 List of @code{<nscd-cache>} objects used by default by
8370 @code{nscd-configuration} (see above).
8372 It enables persistent and aggressive caching of service and host name
8373 lookups. The latter provides better host name lookup performance,
8374 resilience in the face of unreliable name servers, and also better
8375 privacy---often the result of host name lookups is in local cache, so
8376 external name servers do not even need to be queried.
8379 @anchor{syslog-configuration-type}
8382 @deftp {Data Type} syslog-configuration
8383 This data type represents the configuration of the syslog daemon.
8386 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
8387 The syslog daemon to use.
8389 @item @code{config-file} (default: @code{%default-syslog.conf})
8390 The syslog configuration file to use.
8395 @anchor{syslog-service}
8397 @deffn {Scheme Procedure} syslog-service @var{config}
8398 Return a service that runs a syslog daemon according to @var{config}.
8400 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
8401 information on the configuration file syntax.
8404 @anchor{guix-configuration-type}
8405 @deftp {Data Type} guix-configuration
8406 This data type represents the configuration of the Guix build daemon.
8407 @xref{Invoking guix-daemon}, for more information.
8410 @item @code{guix} (default: @var{guix})
8411 The Guix package to use.
8413 @item @code{build-group} (default: @code{"guixbuild"})
8414 Name of the group for build user accounts.
8416 @item @code{build-accounts} (default: @code{10})
8417 Number of build user accounts to create.
8419 @item @code{authorize-key?} (default: @code{#t})
8420 @cindex substitutes, authorization thereof
8421 Whether to authorize the substitute keys listed in
8422 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
8423 (@pxref{Substitutes}).
8425 @vindex %default-authorized-guix-keys
8426 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
8427 The list of authorized key files for archive imports, as a list of
8428 string-valued gexps (@pxref{Invoking guix archive}). By default, it
8429 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
8431 @item @code{use-substitutes?} (default: @code{#t})
8432 Whether to use substitutes.
8434 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
8435 The list of URLs where to look for substitutes by default.
8437 @item @code{extra-options} (default: @code{'()})
8438 List of extra command-line options for @command{guix-daemon}.
8440 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
8441 File where @command{guix-daemon}'s standard output and standard error
8444 @item @code{lsof} (default: @var{lsof})
8445 The lsof package to use.
8450 @deffn {Scheme Procedure} guix-service @var{config}
8451 Return a service that runs the Guix build daemon according to
8455 @deffn {Scheme Procedure} udev-service [#:udev udev]
8456 Run @var{udev}, which populates the @file{/dev} directory dynamically.
8459 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
8460 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
8464 @defvr {Scheme Variable} %random-seed-file
8465 This is the name of the file where some random bytes are saved by
8466 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
8467 It defaults to @file{/var/lib/random-seed}.
8472 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
8473 @cindex keyboard layout
8474 Return a service to load console keymaps from @var{files} using
8475 @command{loadkeys} command. Most likely, you want to load some default
8476 keymap, which can be done like this:
8479 (console-keymap-service "dvorak")
8482 Or, for example, for a Swedish keyboard, you may need to combine
8483 the following keymaps:
8485 (console-keymap-service "se-lat6" "se-fi-lat6")
8488 Also you can specify a full file name (or file names) of your keymap(s).
8489 See @code{man loadkeys} for details.
8495 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
8497 Run @var{gpm}, the general-purpose mouse daemon, with the given
8498 command-line @var{options}. GPM allows users to use the mouse in the console,
8499 notably to select, copy, and paste text. The default value of @var{options}
8500 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
8502 This service is not part of @var{%base-services}.
8505 @anchor{guix-publish-service}
8506 @deffn {Scheme Procedure} guix-publish-service [#:guix @var{guix}] @
8507 [#:port 80] [#:host "localhost"]
8508 Return a service that runs @command{guix publish} listening on @var{host}
8509 and @var{port} (@pxref{Invoking guix publish}).
8511 This assumes that @file{/etc/guix} already contains a signing key pair as
8512 created by @command{guix archive --generate-key} (@pxref{Invoking guix
8513 archive}). If that is not the case, the service will fail to start.
8516 @anchor{rngd-service}
8517 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
8518 [#:device "/dev/hwrng"]
8519 Return a service that runs the @command{rngd} program from @var{rng-tools}
8520 to add @var{device} to the kernel's entropy pool. The service will fail if
8521 @var{device} does not exist.
8524 @anchor{pam-limits-service}
8525 @cindex session limits
8528 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
8530 Return a service that installs a configuration file for the
8531 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
8532 @code{pam_limits} module}. The procedure optionally takes a list of
8533 @code{pam-limits-entry} values, which can be used to specify
8534 @code{ulimit} limits and nice priority limits to user sessions.
8536 The following limits definition sets two hard and soft limits for all
8537 login sessions of users in the @code{realtime} group:
8542 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
8543 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
8546 The first entry increases the maximum realtime priority for
8547 non-privileged processes; the second entry lifts any restriction of the
8548 maximum address space that can be locked in memory. These settings are
8549 commonly used for real-time audio systems.
8552 @node Scheduled Job Execution
8553 @subsubsection Scheduled Job Execution
8557 @cindex scheduling jobs
8558 The @code{(gnu services mcron)} module provides an interface to
8559 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
8560 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
8561 Unix @command{cron} daemon; the main difference is that it is
8562 implemented in Guile Scheme, which provides a lot of flexibility when
8563 specifying the scheduling of jobs and their actions.
8565 The example below defines an operating system that runs the
8566 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
8567 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
8568 well as the @command{mkid} command on behalf of an unprivileged user
8569 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
8570 gexps to introduce job definitions that are passed to mcron
8571 (@pxref{G-Expressions}).
8574 (use-modules (guix) (gnu) (gnu services mcron))
8575 (use-package-modules base idutils)
8577 (define updatedb-job
8578 ;; Run 'updatedb' at 3AM every day. Here we write the
8579 ;; job's action as a Scheme procedure.
8580 #~(job '(next-hour '(3))
8582 (execl (string-append #$findutils "/bin/updatedb")
8584 "--prunepaths=/tmp /var/tmp /gnu/store"))))
8586 (define garbage-collector-job
8587 ;; Collect garbage 5 minutes after midnight every day.
8588 ;; The job's action is a shell command.
8589 #~(job "5 0 * * *" ;Vixie cron syntax
8593 ;; Update the index database as user "charlie" at 12:15PM
8594 ;; and 19:15PM. This runs from the user's home directory.
8595 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
8596 (string-append #$idutils "/bin/mkid src")
8601 (services (cons (mcron-service (list garbage-collector-job
8607 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
8608 for more information on mcron job specifications. Below is the
8609 reference of the mcron service.
8611 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
8612 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
8613 list of gexps denoting mcron job specifications.
8615 This is a shorthand for:
8617 (service mcron-service-type
8618 (mcron-configuration (mcron mcron) (jobs jobs)))
8622 @defvr {Scheme Variable} mcron-service-type
8623 This is the type of the @code{mcron} service, whose value is an
8624 @code{mcron-configuration} object.
8626 This service type can be the target of a service extension that provides
8627 it additional job specifications (@pxref{Service Composition}). In
8628 other words, it is possible to define services that provide additional
8632 @deftp {Data Type} mcron-configuration
8633 Data type representing the configuration of mcron.
8636 @item @code{mcron} (default: @var{mcron2})
8637 The mcron package to use.
8640 This is a list of gexps (@pxref{G-Expressions}), where each gexp
8641 corresponds to an mcron job specification (@pxref{Syntax, mcron job
8642 specifications,, mcron, GNU@tie{}mcron}).
8648 @subsubsection Log Rotation
8651 @cindex log rotation
8653 Log files such as those found in @file{/var/log} tend to grow endlessly,
8654 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
8655 their contents in separate files, possibly compressed. The @code{(gnu
8656 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
8657 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
8659 The example below defines an operating system that provides log rotation
8660 with the default settings.
8663 (use-modules (guix) (gnu))
8664 (use-service-modules admin mcron)
8665 (use-package-modules base idutils)
8669 (services (cons* (mcron-service)
8670 (service rottlog-service-type (rottlog-configuration))
8674 @defvr {Scheme Variable} rottlog-service-type
8675 This is the type of the Rottlog service, whose value is a
8676 @code{rottlog-configuration} object.
8678 This service type can define mcron jobs (@pxref{Scheduled Job
8679 Execution}) to run the rottlog service.
8682 @deftp {Data Type} rottlog-configuration
8683 Data type representing the configuration of rottlog.
8686 @item @code{rottlog} (default: @code{rottlog})
8687 The Rottlog package to use.
8689 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
8690 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
8691 rottlog, GNU Rot[t]log Manual}).
8693 @item @code{periodic-rotations} (default: @code{`(("weekly" %default-rotatations))})
8694 A list of Rottlog period-name/period-config tuples.
8696 For example, taking an example from the Rottlog manual (@pxref{Period
8697 Related File Examples,,, rottlog, GNU Rot[t]log Manual}), a valid tuple
8701 ("daily" ,(plain-file "daily"
8703 /var/log/apache/* @{
8704 storedir apache-archives
8712 This is a list of gexps where each gexp corresponds to an mcron job
8713 specification (@pxref{Scheduled Job Execution}).
8717 @defvr {Scheme Variable} %default-rotations
8718 Specifies weekly rotation of @var{%rotated-files} and
8719 @code{"/var/log/shepherd.log"}.
8722 @defvr {Scheme Variable} %rotated-files
8723 The list of syslog-controlled files to be rotated. By default it is:
8724 @code{'("/var/log/messages" "/var/log/secure")}.
8727 @node Networking Services
8728 @subsubsection Networking Services
8730 The @code{(gnu services networking)} module provides services to configure
8731 the network interface.
8733 @cindex DHCP, networking service
8734 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
8735 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
8736 Protocol (DHCP) client, on all the non-loopback network interfaces.
8739 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
8740 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
8741 Return a service that starts @var{interface} with address @var{ip}. If
8742 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
8743 it must be a string specifying the default network gateway.
8749 @cindex network management
8750 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
8751 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
8752 management daemon that aims to simplify wired and wireless networking.
8754 This service adds the @var{wicd} package to the global profile, providing
8755 several commands to interact with the daemon and configure networking:
8756 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
8757 and @command{wicd-curses} user interfaces.
8760 @cindex NetworkManager
8761 @deffn {Scheme Procedure} network-manager-service @
8762 [#:network-manager @var{network-manager}]
8763 Return a service that runs NetworkManager, a network connection manager
8764 attempting to keep network connectivity active when available.
8768 @deffn {Scheme Procedure} connman-service @
8769 [#:connman @var{connman}]
8770 Return a service that runs @url{https://01.org/connman,Connman}, a network
8773 This service adds the @var{connman} package to the global profile, providing
8774 several the @command{connmanctl} command to interact with the daemon and
8775 configure networking."
8778 @cindex WPA Supplicant
8779 @defvr {Scheme Variable} wpa-supplicant-service-type
8780 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
8781 supplicant}, an authentication daemon required to authenticate against
8782 encrypted WiFi or ethernet networks. It is configured to listen for
8785 The value of this service is the @code{wpa-supplicant} package to use.
8786 Thus, it can be instantiated like this:
8789 (use-modules (gnu services networking)
8790 (gnu packages admin))
8792 (service wpa-supplicant-service-type wpa-supplicant)
8797 @cindex real time clock
8798 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
8799 [#:servers @var{%ntp-servers}] @
8800 [#:allow-large-adjustment? #f]
8801 Return a service that runs the daemon from @var{ntp}, the
8802 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
8803 keep the system clock synchronized with that of @var{servers}.
8804 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
8805 make an initial adjustment of more than 1,000 seconds.
8808 @defvr {Scheme Variable} %ntp-servers
8809 List of host names used as the default NTP servers.
8813 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
8814 Return a service to run the @uref{https://torproject.org, Tor} anonymous
8817 The daemon runs as the @code{tor} unprivileged user. It is passed
8818 @var{config-file}, a file-like object, with an additional @code{User tor} line
8819 and lines for hidden services added via @code{tor-hidden-service}. Run
8820 @command{man tor} for information about the configuration file.
8823 @cindex hidden service
8824 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
8825 Define a new Tor @dfn{hidden service} called @var{name} and implementing
8826 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
8829 '((22 "127.0.0.1:22")
8830 (80 "127.0.0.1:8080"))
8833 In this example, port 22 of the hidden service is mapped to local port 22, and
8834 port 80 is mapped to local port 8080.
8836 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
8837 the @file{hostname} file contains the @code{.onion} host name for the hidden
8840 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
8841 project's documentation} for more information.
8844 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
8845 [#:interface "127.0.0.1"] [#:port 6667] @
8846 [#:extra-settings ""]
8847 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
8848 acts as a gateway between IRC and chat networks.
8850 The daemon will listen to the interface corresponding to the IP address
8851 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
8852 local clients can connect, whereas @code{0.0.0.0} means that connections can
8853 come from any networking interface.
8855 In addition, @var{extra-settings} specifies a string to append to the
8859 Furthermore, @code{(gnu services ssh)} provides the following services.
8863 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
8864 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
8865 [#:allow-empty-passwords? #f] [#:root-login? #f] @
8866 [#:syslog-output? #t] [#:x11-forwarding? #t] @
8867 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
8868 [#:public-key-authentication? #t] [#:initialize? #t]
8869 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
8870 @var{host-key} must designate a file containing the host key, and readable
8873 When @var{daemonic?} is true, @command{lshd} will detach from the
8874 controlling terminal and log its output to syslogd, unless one sets
8875 @var{syslog-output?} to false. Obviously, it also makes lsh-service
8876 depend on existence of syslogd service. When @var{pid-file?} is true,
8877 @command{lshd} writes its PID to the file called @var{pid-file}.
8879 When @var{initialize?} is true, automatically create the seed and host key
8880 upon service activation if they do not exist yet. This may take long and
8881 require interaction.
8883 When @var{initialize?} is false, it is up to the user to initialize the
8884 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
8885 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
8886 basics,,, lsh, LSH Manual}).
8888 When @var{interfaces} is empty, lshd listens for connections on all the
8889 network interfaces; otherwise, @var{interfaces} must be a list of host names
8892 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
8893 passwords, and @var{root-login?} specifies whether to accept log-ins as
8896 The other options should be self-descriptive.
8901 @deffn {Scheme Variable} openssh-service-type
8902 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
8903 shell daemon, @command{sshd}. Its value must be an
8904 @code{openssh-configuration} record as in this example:
8907 (service openssh-service-type
8908 (openssh-configuration
8909 (x11-forwarding? #t)
8910 (permit-root-login 'without-password)))
8913 See below for details about @code{openssh-configuration}.
8916 @deftp {Data Type} openssh-configuration
8917 This is the configuration record for OpenSSH's @command{sshd}.
8920 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
8921 Name of the file where @command{sshd} writes its PID.
8923 @item @code{port-number} (default: @code{22})
8924 TCP port on which @command{sshd} listens for incoming connections.
8926 @item @code{permit-root-login} (default: @code{#f})
8927 This field determines whether and when to allow logins as root. If
8928 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
8929 If it's the symbol @code{'without-password}, then root logins are
8930 permitted but not with password-based authentication.
8932 @item @code{allow-empty-passwords?} (default: @code{#f})
8933 When true, users with empty passwords may log in. When false, they may
8936 @item @code{password-authentication?} (default: @code{#t})
8937 When true, users may log in with their password. When false, they have
8938 other authentication methods.
8940 @item @code{public-key-authentication?} (default: @code{#t})
8941 When true, users may log in using public key authentication. When
8942 false, users have to use other authentication method.
8944 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
8945 This is used only by protocol version 2.
8947 @item @code{rsa-authentication?} (default: @code{#t})
8948 When true, users may log in using pure RSA authentication. When false,
8949 users have to use other means of authentication. This is used only by
8952 @item @code{x11-forwarding?} (default: @code{#f})
8953 When true, forwarding of X11 graphical client connections is
8954 enabled---in other words, @command{ssh} options @option{-X} and
8955 @option{-Y} will work.
8957 @item @code{protocol-number} (default: @code{2})
8958 The SSH protocol number to use.
8962 @deffn {Scheme Procedure} dropbear-service [@var{config}]
8963 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
8964 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
8967 For example, to specify a Dropbear service listening on port 1234, add
8968 this call to the operating system's @code{services} field:
8971 (dropbear-service (dropbear-configuration
8972 (port-number 1234)))
8976 @deftp {Data Type} dropbear-configuration
8977 This data type represents the configuration of a Dropbear SSH daemon.
8980 @item @code{dropbear} (default: @var{dropbear})
8981 The Dropbear package to use.
8983 @item @code{port-number} (default: 22)
8984 The TCP port where the daemon waits for incoming connections.
8986 @item @code{syslog-output?} (default: @code{#t})
8987 Whether to enable syslog output.
8989 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
8990 File name of the daemon's PID file.
8992 @item @code{root-login?} (default: @code{#f})
8993 Whether to allow @code{root} logins.
8995 @item @code{allow-empty-passwords?} (default: @code{#f})
8996 Whether to allow empty passwords.
8998 @item @code{password-authentication?} (default: @code{#t})
8999 Whether to enable password-based authentication.
9003 @defvr {Scheme Variable} %facebook-host-aliases
9004 This variable contains a string for use in @file{/etc/hosts}
9005 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
9006 line contains a entry that maps a known server name of the Facebook
9007 on-line service---e.g., @code{www.facebook.com}---to the local
9008 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
9010 This variable is typically used in the @code{hosts-file} field of an
9011 @code{operating-system} declaration (@pxref{operating-system Reference,
9012 @file{/etc/hosts}}):
9015 (use-modules (gnu) (guix))
9018 (host-name "mymachine")
9021 ;; Create a /etc/hosts file with aliases for "localhost"
9022 ;; and "mymachine", as well as for Facebook servers.
9024 (string-append (local-host-aliases host-name)
9025 %facebook-host-aliases))))
9028 This mechanism can prevent programs running locally, such as Web
9029 browsers, from accessing Facebook.
9032 The @code{(gnu services avahi)} provides the following definition.
9034 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
9035 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
9036 [#:ipv6? #t] [#:wide-area? #f] @
9037 [#:domains-to-browse '()] [#:debug? #f]
9038 Return a service that runs @command{avahi-daemon}, a system-wide
9039 mDNS/DNS-SD responder that allows for service discovery and
9040 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
9041 extends the name service cache daemon (nscd) so that it can resolve
9042 @code{.local} host names using
9043 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
9044 add the @var{avahi} package to the system profile so that commands such as
9045 @command{avahi-browse} are directly usable.
9047 If @var{host-name} is different from @code{#f}, use that as the host name to
9048 publish for this machine; otherwise, use the machine's actual host name.
9050 When @var{publish?} is true, publishing of host names and services is allowed;
9051 in particular, avahi-daemon will publish the machine's host name and IP
9052 address via mDNS on the local network.
9054 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
9056 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
9062 @subsubsection X Window
9065 @cindex X Window System
9066 Support for the X Window graphical display system---specifically
9067 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
9068 there is no @code{xorg-service} procedure. Instead, the X server is
9069 started by the @dfn{login manager}, currently SLiM.
9071 @deftp {Data Type} sddm-configuration
9072 This is the data type representing the sddm service configuration.
9075 @item @code{display-server} (default: "x11")
9076 Select display server to use for the greeter. Valid values are "x11"
9079 @item @code{numlock} (default: "on")
9080 Valid values are "on", "off" or "none".
9082 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
9083 Command to run when halting.
9085 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
9086 Command to run when rebooting.
9088 @item @code{theme} (default "maldives")
9089 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
9091 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
9092 Directory to look for themes.
9094 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
9095 Directory to look for faces.
9097 @item @code{default-path} (default "/run/current-system/profile/bin")
9098 Default PATH to use.
9100 @item @code{minimum-uid} (default 1000)
9101 Minimum UID to display in SDDM.
9103 @item @code{maximum-uid} (default 2000)
9104 Maximum UID to display in SDDM
9106 @item @code{remember-last-user?} (default #t)
9109 @item @code{remember-last-session?} (default #t)
9110 Remember last session.
9112 @item @code{hide-users} (default "")
9113 Usernames to hide from SDDM greeter.
9115 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
9116 Users with shells listed will be hidden from the SDDM greeter.
9118 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
9119 Script to run before starting a wayland session.
9121 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
9122 Directory to look for desktop files starting wayland sessions.
9124 @item @code{xorg-server-path} (default @code{xorg-start-command})
9125 Path to xorg-server.
9127 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
9130 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
9133 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
9134 Script to run after starting xorg-server.
9136 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
9137 Script to run before stopping xorg-server.
9139 @item @code{xsession-command} (default: @code{xinitr })
9140 Script to run before starting a X session.
9142 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
9143 Directory to look for desktop files starting X sessions.
9145 @item @code{minimum-vt} (default: 7)
9148 @item @code{xserver-arguments} (default "-nolisten tcp")
9149 Arguments to pass to xorg-server.
9151 @item @code{auto-login-user} (default "")
9152 User to use for auto-login.
9154 @item @code{auto-login-session} (default "")
9155 Desktop file to use for auto-login.
9157 @item @code{relogin?} (default #f)
9158 Relogin after logout.
9163 @cindex login manager
9164 @deffn {Scheme Procedure} sddm-service config
9165 Return a service that spawns the SDDM graphical login manager for config of
9166 type @code{<sddm-configuration>}.
9169 (sddm-service (sddm-configuration
9170 (auto-login-user "Alice")
9171 (auto-login-session "xfce.desktop")))
9175 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
9176 [#:auto-login? #f] [#:default-user ""] [#:startx] @
9177 [#:theme @var{%default-slim-theme}] @
9178 [#:theme-name @var{%default-slim-theme-name}]
9179 Return a service that spawns the SLiM graphical login manager, which in
9180 turn starts the X display server with @var{startx}, a command as returned by
9181 @code{xorg-start-command}.
9185 SLiM automatically looks for session types described by the @file{.desktop}
9186 files in @file{/run/current-system/profile/share/xsessions} and allows users
9187 to choose a session from the log-in screen using @kbd{F1}. Packages such as
9188 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
9189 adding them to the system-wide set of packages automatically makes them
9190 available at the log-in screen.
9192 In addition, @file{~/.xsession} files are honored. When available,
9193 @file{~/.xsession} must be an executable that starts a window manager
9194 and/or other X clients.
9196 When @var{allow-empty-passwords?} is true, allow logins with an empty
9197 password. When @var{auto-login?} is true, log in automatically as
9200 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
9201 @var{theme} must be a gexp denoting the name of a directory containing the
9202 theme to use. In that case, @var{theme-name} specifies the name of the
9206 @defvr {Scheme Variable} %default-theme
9207 @defvrx {Scheme Variable} %default-theme-name
9208 The G-Expression denoting the default SLiM theme and its name.
9211 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
9212 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
9213 Return a derivation that builds a @var{guile} script to start the X server
9214 from @var{xorg-server}. @var{configuration-file} is the server configuration
9215 file or a derivation that builds it; when omitted, the result of
9216 @code{xorg-configuration-file} is used.
9218 Usually the X server is started by a login manager.
9221 @deffn {Scheme Procedure} xorg-configuration-file @
9222 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
9223 Return a configuration file for the Xorg server containing search paths for
9224 all the common drivers.
9226 @var{drivers} must be either the empty list, in which case Xorg chooses a
9227 graphics driver automatically, or a list of driver names that will be tried in
9228 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
9230 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
9231 appropriate screen resolution; otherwise, it must be a list of
9232 resolutions---e.g., @code{((1024 768) (640 480))}.
9234 Last, @var{extra-config} is a list of strings or objects appended to the
9235 @code{text-file*} argument list. It is used to pass extra text to be added
9236 verbatim to the configuration file.
9239 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
9240 Add @var{package}, a package for a screen-locker or screen-saver whose
9241 command is @var{program}, to the set of setuid programs and add a PAM entry
9242 for it. For example:
9245 (screen-locker-service xlockmore "xlock")
9248 makes the good ol' XlockMore usable.
9252 @node Printing Services
9253 @subsubsection Printing Services
9255 The @code{(gnu services cups)} module provides a Guix service definition
9256 for the CUPS printing service. To add printer support to a GuixSD
9257 system, add a @code{cups-service} to the operating system definition:
9259 @deffn {Scheme Variable} cups-service-type
9260 The service type for the CUPS print server. Its value should be a valid
9261 CUPS configuration (see below). For example:
9263 (service cups-service-type (cups-configuration))
9267 The CUPS configuration controls the basic things about your CUPS
9268 installation: what interfaces it listens on, what to do if a print job
9269 fails, how much logging to do, and so on. To actually add a printer,
9270 you have to visit the @url{http://localhost:631} URL, or use a tool such
9271 as GNOME's printer configuration services. By default, configuring a
9272 CUPS service will generate a self-signed certificate if needed, for
9273 secure connections to the print server.
9275 One way you might want to customize CUPS is to enable or disable the web
9276 interface. You can do that directly, like this:
9279 (service cups-service-type
9281 (web-interface? #f)))
9284 The available configuration parameters follow. Each parameter
9285 definition is preceded by its type; for example, @samp{string-list foo}
9286 indicates that the @code{foo} parameter should be specified as a list of
9287 strings. There is also a way to specify the configuration as a string,
9288 if you have an old @code{cupsd.conf} file that you want to port over
9289 from some other system; see the end for more details.
9291 @c The following documentation was initially generated by
9292 @c (generate-documentation) in (gnu services cups). Manually maintained
9293 @c documentation is better, so we shouldn't hesitate to edit below as
9294 @c needed. However if the change you want to make to this documentation
9295 @c can be done in an automated way, it's probably easier to change
9296 @c (generate-documentation) than to make it below and have to deal with
9297 @c the churn as CUPS updates.
9300 Available @code{cups-configuration} fields are:
9302 @deftypevr {@code{cups-configuration} parameter} package cups
9306 @deftypevr {@code{cups-configuration} parameter} package-list extensions
9307 Drivers and other extensions to the CUPS package.
9310 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
9311 Configuration of where to write logs, what directories to use for print
9312 spools, and related privileged configuration parameters.
9314 Available @code{files-configuration} fields are:
9316 @deftypevr {@code{files-configuration} parameter} log-location access-log
9317 Defines the access log filename. Specifying a blank filename disables
9318 access log generation. The value @code{stderr} causes log entries to be
9319 sent to the standard error file when the scheduler is running in the
9320 foreground, or to the system log daemon when run in the background. The
9321 value @code{syslog} causes log entries to be sent to the system log
9322 daemon. The server name may be included in filenames using the string
9323 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
9325 Defaults to @samp{"/var/log/cups/access_log"}.
9328 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
9329 Where CUPS should cache data.
9331 Defaults to @samp{"/var/cache/cups"}.
9334 @deftypevr {@code{files-configuration} parameter} string config-file-perm
9335 Specifies the permissions for all configuration files that the scheduler
9338 Note that the permissions for the printers.conf file are currently
9339 masked to only allow access from the scheduler user (typically root).
9340 This is done because printer device URIs sometimes contain sensitive
9341 authentication information that should not be generally known on the
9342 system. There is no way to disable this security feature.
9344 Defaults to @samp{"0640"}.
9347 @deftypevr {@code{files-configuration} parameter} log-location error-log
9348 Defines the error log filename. Specifying a blank filename disables
9349 access log generation. The value @code{stderr} causes log entries to be
9350 sent to the standard error file when the scheduler is running in the
9351 foreground, or to the system log daemon when run in the background. The
9352 value @code{syslog} causes log entries to be sent to the system log
9353 daemon. The server name may be included in filenames using the string
9354 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
9356 Defaults to @samp{"/var/log/cups/error_log"}.
9359 @deftypevr {@code{files-configuration} parameter} string fatal-errors
9360 Specifies which errors are fatal, causing the scheduler to exit. The
9365 No errors are fatal.
9368 All of the errors below are fatal.
9371 Browsing initialization errors are fatal, for example failed connections
9372 to the DNS-SD daemon.
9375 Configuration file syntax errors are fatal.
9378 Listen or Port errors are fatal, except for IPv6 failures on the
9379 loopback or @code{any} addresses.
9382 Log file creation or write errors are fatal.
9385 Bad startup file permissions are fatal, for example shared TLS
9386 certificate and key files with world-read permissions.
9389 Defaults to @samp{"all -browse"}.
9392 @deftypevr {@code{files-configuration} parameter} boolean file-device?
9393 Specifies whether the file pseudo-device can be used for new printer
9394 queues. The URI @uref{file:///dev/null} is always allowed.
9396 Defaults to @samp{#f}.
9399 @deftypevr {@code{files-configuration} parameter} string group
9400 Specifies the group name or ID that will be used when executing external
9403 Defaults to @samp{"lp"}.
9406 @deftypevr {@code{files-configuration} parameter} string log-file-perm
9407 Specifies the permissions for all log files that the scheduler writes.
9409 Defaults to @samp{"0644"}.
9412 @deftypevr {@code{files-configuration} parameter} log-location page-log
9413 Defines the page log filename. Specifying a blank filename disables
9414 access log generation. The value @code{stderr} causes log entries to be
9415 sent to the standard error file when the scheduler is running in the
9416 foreground, or to the system log daemon when run in the background. The
9417 value @code{syslog} causes log entries to be sent to the system log
9418 daemon. The server name may be included in filenames using the string
9419 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
9421 Defaults to @samp{"/var/log/cups/page_log"}.
9424 @deftypevr {@code{files-configuration} parameter} string remote-root
9425 Specifies the username that is associated with unauthenticated accesses
9426 by clients claiming to be the root user. The default is @code{remroot}.
9428 Defaults to @samp{"remroot"}.
9431 @deftypevr {@code{files-configuration} parameter} file-name request-root
9432 Specifies the directory that contains print jobs and other HTTP request
9435 Defaults to @samp{"/var/spool/cups"}.
9438 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
9439 Specifies the level of security sandboxing that is applied to print
9440 filters, backends, and other child processes of the scheduler; either
9441 @code{relaxed} or @code{strict}. This directive is currently only
9442 used/supported on macOS.
9444 Defaults to @samp{strict}.
9447 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
9448 Specifies the location of TLS certificates and private keys. CUPS will
9449 look for public and private keys in this directory: a @code{.crt} files
9450 for PEM-encoded certificates and corresponding @code{.key} files for
9451 PEM-encoded private keys.
9453 Defaults to @samp{"/etc/cups/ssl"}.
9456 @deftypevr {@code{files-configuration} parameter} file-name server-root
9457 Specifies the directory containing the server configuration files.
9459 Defaults to @samp{"/etc/cups"}.
9462 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
9463 Specifies whether the scheduler calls fsync(2) after writing
9464 configuration or state files.
9466 Defaults to @samp{#f}.
9469 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
9470 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
9473 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
9474 Specifies the directory where temporary files are stored.
9476 Defaults to @samp{"/var/spool/cups/tmp"}.
9479 @deftypevr {@code{files-configuration} parameter} string user
9480 Specifies the user name or ID that is used when running external
9483 Defaults to @samp{"lp"}.
9487 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
9488 Specifies the logging level for the AccessLog file. The @code{config}
9489 level logs when printers and classes are added, deleted, or modified and
9490 when configuration files are accessed or updated. The @code{actions}
9491 level logs when print jobs are submitted, held, released, modified, or
9492 canceled, and any of the conditions for @code{config}. The @code{all}
9493 level logs all requests.
9495 Defaults to @samp{actions}.
9498 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
9499 Specifies whether to purge job history data automatically when it is no
9500 longer required for quotas.
9502 Defaults to @samp{#f}.
9505 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
9506 Specifies which protocols to use for local printer sharing.
9508 Defaults to @samp{dnssd}.
9511 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
9512 Specifies whether the CUPS web interface is advertised.
9514 Defaults to @samp{#f}.
9517 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
9518 Specifies whether shared printers are advertised.
9520 Defaults to @samp{#f}.
9523 @deftypevr {@code{cups-configuration} parameter} string classification
9524 Specifies the security classification of the server. Any valid banner
9525 name can be used, including "classified", "confidential", "secret",
9526 "topsecret", and "unclassified", or the banner can be omitted to disable
9527 secure printing functions.
9529 Defaults to @samp{""}.
9532 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
9533 Specifies whether users may override the classification (cover page) of
9534 individual print jobs using the @code{job-sheets} option.
9536 Defaults to @samp{#f}.
9539 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
9540 Specifies the default type of authentication to use.
9542 Defaults to @samp{Basic}.
9545 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
9546 Specifies whether encryption will be used for authenticated requests.
9548 Defaults to @samp{Required}.
9551 @deftypevr {@code{cups-configuration} parameter} string default-language
9552 Specifies the default language to use for text and web content.
9554 Defaults to @samp{"en"}.
9557 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
9558 Specifies the default paper size for new print queues. @samp{"Auto"}
9559 uses a locale-specific default, while @samp{"None"} specifies there is
9560 no default paper size. Specific size names are typically
9561 @samp{"Letter"} or @samp{"A4"}.
9563 Defaults to @samp{"Auto"}.
9566 @deftypevr {@code{cups-configuration} parameter} string default-policy
9567 Specifies the default access policy to use.
9569 Defaults to @samp{"default"}.
9572 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
9573 Specifies whether local printers are shared by default.
9575 Defaults to @samp{#t}.
9578 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
9579 Specifies the delay for updating of configuration and state files, in
9580 seconds. A value of 0 causes the update to happen as soon as possible,
9581 typically within a few milliseconds.
9583 Defaults to @samp{30}.
9586 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
9587 Specifies what to do when an error occurs. Possible values are
9588 @code{abort-job}, which will discard the failed print job;
9589 @code{retry-job}, which will retry the job at a later time;
9590 @code{retry-this-job}, which retries the failed job immediately; and
9591 @code{stop-printer}, which stops the printer.
9593 Defaults to @samp{stop-printer}.
9596 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
9597 Specifies the maximum cost of filters that are run concurrently, which
9598 can be used to minimize disk, memory, and CPU resource problems. A
9599 limit of 0 disables filter limiting. An average print to a
9600 non-PostScript printer needs a filter limit of about 200. A PostScript
9601 printer needs about half that (100). Setting the limit below these
9602 thresholds will effectively limit the scheduler to printing a single job
9605 Defaults to @samp{0}.
9608 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
9609 Specifies the scheduling priority of filters that are run to print a
9610 job. The nice value ranges from 0, the highest priority, to 19, the
9613 Defaults to @samp{0}.
9616 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
9617 Specifies whether to do reverse lookups on connecting clients. The
9618 @code{double} setting causes @code{cupsd} to verify that the hostname
9619 resolved from the address matches one of the addresses returned for that
9620 hostname. Double lookups also prevent clients with unregistered
9621 addresses from connecting to your server. Only set this option to
9622 @code{#t} or @code{double} if absolutely required.
9624 Defaults to @samp{#f}.
9627 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
9628 Specifies the number of seconds to wait before killing the filters and
9629 backend associated with a canceled or held job.
9631 Defaults to @samp{30}.
9634 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
9635 Specifies the interval between retries of jobs in seconds. This is
9636 typically used for fax queues but can also be used with normal print
9637 queues whose error policy is @code{retry-job} or
9638 @code{retry-current-job}.
9640 Defaults to @samp{30}.
9643 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
9644 Specifies the number of retries that are done for jobs. This is
9645 typically used for fax queues but can also be used with normal print
9646 queues whose error policy is @code{retry-job} or
9647 @code{retry-current-job}.
9649 Defaults to @samp{5}.
9652 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
9653 Specifies whether to support HTTP keep-alive connections.
9655 Defaults to @samp{#t}.
9658 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
9659 Specifies how long an idle client connection remains open, in seconds.
9661 Defaults to @samp{30}.
9664 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
9665 Specifies the maximum size of print files, IPP requests, and HTML form
9666 data. A limit of 0 disables the limit check.
9668 Defaults to @samp{0}.
9671 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
9672 Listens on the specified interfaces for connections. Valid values are
9673 of the form @var{address}:@var{port}, where @var{address} is either an
9674 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
9675 indicate all addresses. Values can also be file names of local UNIX
9676 domain sockets. The Listen directive is similar to the Port directive
9677 but allows you to restrict access to specific interfaces or networks.
9680 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
9681 Specifies the number of pending connections that will be allowed. This
9682 normally only affects very busy servers that have reached the MaxClients
9683 limit, but can also be triggered by large numbers of simultaneous
9684 connections. When the limit is reached, the operating system will
9685 refuse additional connections until the scheduler can accept the pending
9688 Defaults to @samp{128}.
9691 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
9692 Specifies a set of additional access controls.
9694 Available @code{location-access-controls} fields are:
9696 @deftypevr {@code{location-access-controls} parameter} file-name path
9697 Specifies the URI path to which the access control applies.
9700 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
9701 Access controls for all access to this path, in the same format as the
9702 @code{access-controls} of @code{operation-access-control}.
9704 Defaults to @samp{()}.
9707 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
9708 Access controls for method-specific access to this path.
9710 Defaults to @samp{()}.
9712 Available @code{method-access-controls} fields are:
9714 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
9715 If @code{#t}, apply access controls to all methods except the listed
9716 methods. Otherwise apply to only the listed methods.
9718 Defaults to @samp{#f}.
9721 @deftypevr {@code{method-access-controls} parameter} method-list methods
9722 Methods to which this access control applies.
9724 Defaults to @samp{()}.
9727 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
9728 Access control directives, as a list of strings. Each string should be
9729 one directive, such as "Order allow,deny".
9731 Defaults to @samp{()}.
9736 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
9737 Specifies the number of debugging messages that are retained for logging
9738 if an error occurs in a print job. Debug messages are logged regardless
9739 of the LogLevel setting.
9741 Defaults to @samp{100}.
9744 @deftypevr {@code{cups-configuration} parameter} log-level log-level
9745 Specifies the level of logging for the ErrorLog file. The value
9746 @code{none} stops all logging while @code{debug2} logs everything.
9748 Defaults to @samp{info}.
9751 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
9752 Specifies the format of the date and time in the log files. The value
9753 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
9755 Defaults to @samp{standard}.
9758 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
9759 Specifies the maximum number of simultaneous clients that are allowed by
9762 Defaults to @samp{100}.
9765 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
9766 Specifies the maximum number of simultaneous clients that are allowed
9767 from a single address.
9769 Defaults to @samp{100}.
9772 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
9773 Specifies the maximum number of copies that a user can print of each
9776 Defaults to @samp{9999}.
9779 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
9780 Specifies the maximum time a job may remain in the @code{indefinite}
9781 hold state before it is canceled. A value of 0 disables cancellation of
9784 Defaults to @samp{0}.
9787 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
9788 Specifies the maximum number of simultaneous jobs that are allowed. Set
9789 to 0 to allow an unlimited number of jobs.
9791 Defaults to @samp{500}.
9794 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
9795 Specifies the maximum number of simultaneous jobs that are allowed per
9796 printer. A value of 0 allows up to MaxJobs jobs per printer.
9798 Defaults to @samp{0}.
9801 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
9802 Specifies the maximum number of simultaneous jobs that are allowed per
9803 user. A value of 0 allows up to MaxJobs jobs per user.
9805 Defaults to @samp{0}.
9808 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
9809 Specifies the maximum time a job may take to print before it is
9810 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
9812 Defaults to @samp{10800}.
9815 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
9816 Specifies the maximum size of the log files before they are rotated, in
9817 bytes. The value 0 disables log rotation.
9819 Defaults to @samp{1048576}.
9822 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
9823 Specifies the maximum amount of time to allow between files in a
9824 multiple file print job, in seconds.
9826 Defaults to @samp{300}.
9829 @deftypevr {@code{cups-configuration} parameter} string page-log-format
9830 Specifies the format of PageLog lines. Sequences beginning with percent
9831 (@samp{%}) characters are replaced with the corresponding information,
9832 while all other characters are copied literally. The following percent
9833 sequences are recognized:
9837 insert a single percent character
9840 insert the value of the specified IPP attribute
9843 insert the number of copies for the current page
9846 insert the current page number
9849 insert the current date and time in common log format
9855 insert the printer name
9861 A value of the empty string disables page logging. The string @code{%p
9862 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
9863 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
9866 Defaults to @samp{""}.
9869 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
9870 Passes the specified environment variable(s) to child processes; a list
9873 Defaults to @samp{()}.
9876 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
9877 Specifies named access control policies.
9879 Available @code{policy-configuration} fields are:
9881 @deftypevr {@code{policy-configuration} parameter} string name
9885 @deftypevr {@code{policy-configuration} parameter} string job-private-access
9886 Specifies an access list for a job's private values. @code{@@ACL} maps
9887 to the printer's requesting-user-name-allowed or
9888 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
9889 owner. @code{@@SYSTEM} maps to the groups listed for the
9890 @code{system-group} field of the @code{files-config} configuration,
9891 which is reified into the @code{cups-files.conf(5)} file. Other
9892 possible elements of the access list include specific user names, and
9893 @code{@@@var{group}} to indicate members of a specific group. The
9894 access list may also be simply @code{all} or @code{default}.
9896 Defaults to @samp{"@@OWNER @@SYSTEM"}.
9899 @deftypevr {@code{policy-configuration} parameter} string job-private-values
9900 Specifies the list of job values to make private, or @code{all},
9901 @code{default}, or @code{none}.
9903 Defaults to @samp{"job-name job-originating-host-name
9904 job-originating-user-name phone"}.
9907 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
9908 Specifies an access list for a subscription's private values.
9909 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
9910 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
9911 owner. @code{@@SYSTEM} maps to the groups listed for the
9912 @code{system-group} field of the @code{files-config} configuration,
9913 which is reified into the @code{cups-files.conf(5)} file. Other
9914 possible elements of the access list include specific user names, and
9915 @code{@@@var{group}} to indicate members of a specific group. The
9916 access list may also be simply @code{all} or @code{default}.
9918 Defaults to @samp{"@@OWNER @@SYSTEM"}.
9921 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
9922 Specifies the list of job values to make private, or @code{all},
9923 @code{default}, or @code{none}.
9925 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
9926 notify-subscriber-user-name notify-user-data"}.
9929 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
9930 Access control by IPP operation.
9932 Defaults to @samp{()}.
9936 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
9937 Specifies whether job files (documents) are preserved after a job is
9938 printed. If a numeric value is specified, job files are preserved for
9939 the indicated number of seconds after printing. Otherwise a boolean
9940 value applies indefinitely.
9942 Defaults to @samp{86400}.
9945 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
9946 Specifies whether the job history is preserved after a job is printed.
9947 If a numeric value is specified, the job history is preserved for the
9948 indicated number of seconds after printing. If @code{#t}, the job
9949 history is preserved until the MaxJobs limit is reached.
9951 Defaults to @samp{#t}.
9954 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
9955 Specifies the amount of time to wait for job completion before
9956 restarting the scheduler.
9958 Defaults to @samp{30}.
9961 @deftypevr {@code{cups-configuration} parameter} string rip-cache
9962 Specifies the maximum amount of memory to use when converting documents
9963 into bitmaps for a printer.
9965 Defaults to @samp{"128m"}.
9968 @deftypevr {@code{cups-configuration} parameter} string server-admin
9969 Specifies the email address of the server administrator.
9971 Defaults to @samp{"root@@localhost.localdomain"}.
9974 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
9975 The ServerAlias directive is used for HTTP Host header validation when
9976 clients connect to the scheduler from external interfaces. Using the
9977 special name @code{*} can expose your system to known browser-based DNS
9978 rebinding attacks, even when accessing sites through a firewall. If the
9979 auto-discovery of alternate names does not work, we recommend listing
9980 each alternate name with a ServerAlias directive instead of using
9983 Defaults to @samp{*}.
9986 @deftypevr {@code{cups-configuration} parameter} string server-name
9987 Specifies the fully-qualified host name of the server.
9989 Defaults to @samp{"localhost"}.
9992 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
9993 Specifies what information is included in the Server header of HTTP
9994 responses. @code{None} disables the Server header. @code{ProductOnly}
9995 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
9996 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
9997 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
9998 the output of the @code{uname} command. @code{Full} reports @code{CUPS
9999 2.0.0 (@var{uname}) IPP/2.0}.
10001 Defaults to @samp{Minimal}.
10004 @deftypevr {@code{cups-configuration} parameter} string set-env
10005 Set the specified environment variable to be passed to child processes.
10007 Defaults to @samp{"variable value"}.
10010 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
10011 Listens on the specified interfaces for encrypted connections. Valid
10012 values are of the form @var{address}:@var{port}, where @var{address} is
10013 either an IPv6 address enclosed in brackets, an IPv4 address, or
10014 @code{*} to indicate all addresses.
10016 Defaults to @samp{()}.
10019 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
10020 Sets encryption options. By default, CUPS only supports encryption
10021 using TLS v1.0 or higher using known secure cipher suites. The
10022 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
10023 required for some older clients that do not implement newer ones. The
10024 @code{AllowSSL3} option enables SSL v3.0, which is required for some
10025 older clients that do not support TLS v1.0.
10027 Defaults to @samp{()}.
10030 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
10031 Specifies whether the scheduler requires clients to strictly adhere to
10032 the IPP specifications.
10034 Defaults to @samp{#f}.
10037 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
10038 Specifies the HTTP request timeout, in seconds.
10040 Defaults to @samp{300}.
10044 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
10045 Specifies whether the web interface is enabled.
10047 Defaults to @samp{#f}.
10050 At this point you're probably thinking ``oh dear, Guix manual, I like
10051 you but you can stop already with the configuration options''. Indeed.
10052 However, one more point: it could be that you have an existing
10053 @code{cupsd.conf} that you want to use. In that case, you can pass an
10054 @code{opaque-cups-configuration} as the configuration of a
10055 @code{cups-service-type}.
10057 Available @code{opaque-cups-configuration} fields are:
10059 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
10063 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
10064 The contents of the @code{cupsd.conf}, as a string.
10067 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
10068 The contents of the @code{cups-files.conf} file, as a string.
10071 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
10072 strings of the same name, you could instantiate a CUPS service like
10076 (service cups-service-type
10077 (opaque-cups-configuration
10078 (cupsd.conf cupsd.conf)
10079 (cups-files.conf cups-files.conf)))
10083 @node Desktop Services
10084 @subsubsection Desktop Services
10086 The @code{(gnu services desktop)} module provides services that are
10087 usually useful in the context of a ``desktop'' setup---that is, on a
10088 machine running a graphical display server, possibly with graphical user
10089 interfaces, etc. It also defines services that provide specific desktop
10090 environments like GNOME and XFCE.
10092 To simplify things, the module defines a variable containing the set of
10093 services that users typically expect on a machine with a graphical
10094 environment and networking:
10096 @defvr {Scheme Variable} %desktop-services
10097 This is a list of services that builds upon @var{%base-services} and
10098 adds or adjusts services for a typical ``desktop'' setup.
10100 In particular, it adds a graphical login manager (@pxref{X Window,
10101 @code{slim-service}}), screen lockers,
10102 a network management tool (@pxref{Networking
10103 Services, @code{wicd-service}}), energy and color management services,
10104 the @code{elogind} login and seat manager, the Polkit privilege service,
10105 the GeoClue location service, an NTP client (@pxref{Networking
10106 Services}), the Avahi daemon, and has the name service switch service
10107 configured to be able to use @code{nss-mdns} (@pxref{Name Service
10111 The @var{%desktop-services} variable can be used as the @code{services}
10112 field of an @code{operating-system} declaration (@pxref{operating-system
10113 Reference, @code{services}}).
10115 Additionally, the @code{gnome-desktop-service} and
10116 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
10117 system. To ``add GNOME'' means that system-level services like the
10118 backlight adjustment helpers and the power management utilities are
10119 added to the system, extending @code{polkit} and @code{dbus}
10120 appropriately, allowing GNOME to operate with elevated privileges on a
10121 limited number of special-purpose system interfaces. Additionally,
10122 adding a service made by @code{gnome-desktop-service} adds the GNOME
10123 metapackage to the system profile. Likewise, adding the XFCE service
10124 not only adds the @code{xfce} metapackage to the system profile, but it
10125 also gives the Thunar file manager the ability to open a ``root-mode''
10126 file management window, if the user authenticates using the
10127 administrator's password via the standard polkit graphical interface.
10129 @deffn {Scheme Procedure} gnome-desktop-service
10130 Return a service that adds the @code{gnome} package to the system
10131 profile, and extends polkit with the actions from
10132 @code{gnome-settings-daemon}.
10135 @deffn {Scheme Procedure} xfce-desktop-service
10136 Return a service that adds the @code{xfce} package to the system profile,
10137 and extends polkit with the ability for @code{thunar} to manipulate the
10138 file system as root from within a user session, after the user has
10139 authenticated with the administrator's password.
10142 Because the GNOME and XFCE desktop services pull in so many packages,
10143 the default @code{%desktop-services} variable doesn't include either of
10144 them by default. To add GNOME or XFCE, just @code{cons} them onto
10145 @code{%desktop-services} in the @code{services} field of your
10146 @code{operating-system}:
10149 (use-modules (gnu))
10150 (use-service-modules desktop)
10153 ;; cons* adds items to the list given as its last argument.
10154 (services (cons* (gnome-desktop-service)
10155 (xfce-desktop-service)
10156 %desktop-services))
10160 These desktop environments will then be available as options in the
10161 graphical login window.
10163 The actual service definitions included in @code{%desktop-services} and
10164 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
10165 are described below.
10167 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
10168 Return a service that runs the ``system bus'', using @var{dbus}, with
10169 support for @var{services}.
10171 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
10172 facility. Its system bus is used to allow system services to communicate
10173 and to be notified of system-wide events.
10175 @var{services} must be a list of packages that provide an
10176 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
10177 and policy files. For example, to allow avahi-daemon to use the system bus,
10178 @var{services} must be equal to @code{(list avahi)}.
10181 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
10182 Return a service that runs the @code{elogind} login and
10183 seat management daemon. @uref{https://github.com/andywingo/elogind,
10184 Elogind} exposes a D-Bus interface that can be used to know which users
10185 are logged in, know what kind of sessions they have open, suspend the
10186 system, inhibit system suspend, reboot the system, and other tasks.
10188 Elogind handles most system-level power events for a computer, for
10189 example suspending the system when a lid is closed, or shutting it down
10190 when the power button is pressed.
10192 The @var{config} keyword argument specifies the configuration for
10193 elogind, and should be the result of an @code{(elogind-configuration
10194 (@var{parameter} @var{value})...)} invocation. Available parameters and
10195 their default values are:
10198 @item kill-user-processes?
10200 @item kill-only-users
10202 @item kill-exclude-users
10204 @item inhibit-delay-max-seconds
10206 @item handle-power-key
10208 @item handle-suspend-key
10210 @item handle-hibernate-key
10212 @item handle-lid-switch
10214 @item handle-lid-switch-docked
10216 @item power-key-ignore-inhibited?
10218 @item suspend-key-ignore-inhibited?
10220 @item hibernate-key-ignore-inhibited?
10222 @item lid-switch-ignore-inhibited?
10224 @item holdoff-timeout-seconds
10228 @item idle-action-seconds
10230 @item runtime-directory-size-percent
10232 @item runtime-directory-size
10236 @item suspend-state
10237 @code{("mem" "standby" "freeze")}
10240 @item hibernate-state
10242 @item hibernate-mode
10243 @code{("platform" "shutdown")}
10244 @item hybrid-sleep-state
10246 @item hybrid-sleep-mode
10247 @code{("suspend" "platform" "shutdown")}
10251 @deffn {Scheme Procedure} polkit-service @
10252 [#:polkit @var{polkit}]
10253 Return a service that runs the
10254 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
10255 management service}, which allows system administrators to grant access to
10256 privileged operations in a structured way. By querying the Polkit service, a
10257 privileged system component can know when it should grant additional
10258 capabilities to ordinary users. For example, an ordinary user can be granted
10259 the capability to suspend the system if the user is logged in locally.
10262 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
10263 [#:watts-up-pro? #f] @
10264 [#:poll-batteries? #t] @
10265 [#:ignore-lid? #f] @
10266 [#:use-percentage-for-policy? #f] @
10267 [#:percentage-low 10] @
10268 [#:percentage-critical 3] @
10269 [#:percentage-action 2] @
10270 [#:time-low 1200] @
10271 [#:time-critical 300] @
10272 [#:time-action 120] @
10273 [#:critical-power-action 'hybrid-sleep]
10274 Return a service that runs @uref{http://upower.freedesktop.org/,
10275 @command{upowerd}}, a system-wide monitor for power consumption and battery
10276 levels, with the given configuration settings. It implements the
10277 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
10281 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
10282 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
10283 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
10284 notifications and ways to mount/unmount disks. Programs that talk to UDisks
10285 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
10288 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
10289 Return a service that runs @command{colord}, a system service with a D-Bus
10290 interface to manage the color profiles of input and output devices such as
10291 screens and scanners. It is notably used by the GNOME Color Manager graphical
10292 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
10293 site} for more information.
10296 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
10297 Return a configuration allowing an application to access GeoClue
10298 location data. @var{name} is the Desktop ID of the application, without
10299 the @code{.desktop} part. If @var{allowed?} is true, the application
10300 will have access to location information by default. The boolean
10301 @var{system?} value indicates whether an application is a system component
10302 or not. Finally @var{users} is a list of UIDs of all users for which
10303 this application is allowed location info access. An empty users list
10304 means that all users are allowed.
10307 @defvr {Scheme Variable} %standard-geoclue-applications
10308 The standard list of well-known GeoClue application configurations,
10309 granting authority to the GNOME date-and-time utility to ask for the
10310 current location in order to set the time zone, and allowing the
10311 IceCat and Epiphany web browsers to request location information.
10312 IceCat and Epiphany both query the user before allowing a web page to
10313 know the user's location.
10316 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
10317 [#:whitelist '()] @
10318 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
10319 [#:submit-data? #f]
10320 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
10321 [#:submission-nick "geoclue"] @
10322 [#:applications %standard-geoclue-applications]
10323 Return a service that runs the GeoClue location service. This service
10324 provides a D-Bus interface to allow applications to request access to a
10325 user's physical location, and optionally to add information to online
10326 location databases. See
10327 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
10328 web site} for more information.
10331 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
10332 Return a service that runs the @command{bluetoothd} daemon, which manages
10333 all the Bluetooth devices and provides a number of D-Bus interfaces.
10335 Users need to be in the @code{lp} group to access the D-Bus service.
10338 @node Database Services
10339 @subsubsection Database Services
10343 The @code{(gnu services databases)} module provides the following services.
10345 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
10346 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
10347 [#:port 5432] [#:locale ``en_US.utf8'']
10348 Return a service that runs @var{postgresql}, the PostgreSQL database
10351 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
10352 creates a database cluster with @var{locale} as the default
10353 locale, stored in @var{data-directory}. It then listens on @var{port}.
10356 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
10357 Return a service that runs @command{mysqld}, the MySQL or MariaDB
10360 The optional @var{config} argument specifies the configuration for
10361 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
10364 @deftp {Data Type} mysql-configuration
10365 Data type representing the configuration of @var{mysql-service}.
10368 @item @code{mysql} (default: @var{mariadb})
10369 Package object of the MySQL database server, can be either @var{mariadb}
10372 For MySQL, a temporary root password will be displayed at activation time.
10373 For MariaDB, the root password is empty.
10375 @item @code{port} (default: @code{3306})
10376 TCP port on which the database server listens for incoming connections.
10380 @defvr {Scheme Variable} redis-service-type
10381 This is the service type for the @uref{https://redis.io/, Redis}
10382 key/value store, whose value is a @code{redis-configuration} object.
10385 @deftp {Data Type} redis-configuration
10386 Data type representing the configuration of redis.
10389 @item @code{redis} (default: @code{redis})
10390 The Redis package to use.
10392 @item @code{bind} (default: @code{"127.0.0.1"})
10393 Network interface on which to listen.
10395 @item @code{port} (default: @code{6379})
10396 Port on which to accept connections on, a value of 0 will disable
10397 listining on a TCP socket.
10399 @item @code{working-directory} (default: @code{"/var/lib/redis"})
10400 Directory in which to store the database and related files.
10404 @node Mail Services
10405 @subsubsection Mail Services
10409 The @code{(gnu services mail)} module provides Guix service definitions
10410 for email services: IMAP, POP3, and LMTP servers, as well as mail
10411 transport agents (MTAs). Lots of acronyms! These services are detailed
10412 in the subsections below.
10414 @subsubheading Dovecot Service
10416 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
10417 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
10420 By default, Dovecot does not need much configuration; the default
10421 configuration object created by @code{(dovecot-configuration)} will
10422 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
10423 certificate will be generated for TLS-protected connections, though
10424 Dovecot will also listen on cleartext ports by default. There are a
10425 number of options, though, which mail administrators might need to change,
10426 and as is the case with other services, Guix allows the system
10427 administrator to specify these parameters via a uniform Scheme interface.
10429 For example, to specify that mail is located at @code{maildir~/.mail},
10430 one would instantiate the Dovecot service like this:
10433 (dovecot-service #:config
10434 (dovecot-configuration
10435 (mail-location "maildir:~/.mail")))
10438 The available configuration parameters follow. Each parameter
10439 definition is preceded by its type; for example, @samp{string-list foo}
10440 indicates that the @code{foo} parameter should be specified as a list of
10441 strings. There is also a way to specify the configuration as a string,
10442 if you have an old @code{dovecot.conf} file that you want to port over
10443 from some other system; see the end for more details.
10445 @c The following documentation was initially generated by
10446 @c (generate-documentation) in (gnu services mail). Manually maintained
10447 @c documentation is better, so we shouldn't hesitate to edit below as
10448 @c needed. However if the change you want to make to this documentation
10449 @c can be done in an automated way, it's probably easier to change
10450 @c (generate-documentation) than to make it below and have to deal with
10451 @c the churn as dovecot updates.
10453 Available @code{dovecot-configuration} fields are:
10455 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
10456 The dovecot package.
10459 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
10460 A list of IPs or hosts where to listen for connections. @samp{*}
10461 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
10462 interfaces. If you want to specify non-default ports or anything more
10463 complex, customize the address and port fields of the
10464 @samp{inet-listener} of the specific services you are interested in.
10467 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
10468 List of protocols we want to serve. Available protocols include
10469 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
10471 Available @code{protocol-configuration} fields are:
10473 @deftypevr {@code{protocol-configuration} parameter} string name
10474 The name of the protocol.
10477 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
10478 UNIX socket path to the master authentication server to find users.
10479 This is used by imap (for shared users) and lda.
10480 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
10483 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
10484 Space separated list of plugins to load.
10487 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
10488 Maximum number of IMAP connections allowed for a user from each IP
10489 address. NOTE: The username is compared case-sensitively.
10490 Defaults to @samp{10}.
10495 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
10496 List of services to enable. Available services include @samp{imap},
10497 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
10500 Available @code{service-configuration} fields are:
10502 @deftypevr {@code{service-configuration} parameter} string kind
10503 The service kind. Valid values include @code{director},
10504 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
10505 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
10506 @code{tcpwrap}, @code{quota-warning}, or anything else.
10509 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
10510 Listeners for the service. A listener is either a
10511 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
10512 an @code{inet-listener-configuration}.
10513 Defaults to @samp{()}.
10515 Available @code{unix-listener-configuration} fields are:
10517 @deftypevr {@code{unix-listener-configuration} parameter} file-name path
10518 The file name on which to listen.
10521 @deftypevr {@code{unix-listener-configuration} parameter} string mode
10522 The access mode for the socket.
10523 Defaults to @samp{"0600"}.
10526 @deftypevr {@code{unix-listener-configuration} parameter} string user
10527 The user to own the socket.
10528 Defaults to @samp{""}.
10531 @deftypevr {@code{unix-listener-configuration} parameter} string group
10532 The group to own the socket.
10533 Defaults to @samp{""}.
10537 Available @code{fifo-listener-configuration} fields are:
10539 @deftypevr {@code{fifo-listener-configuration} parameter} file-name path
10540 The file name on which to listen.
10543 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
10544 The access mode for the socket.
10545 Defaults to @samp{"0600"}.
10548 @deftypevr {@code{fifo-listener-configuration} parameter} string user
10549 The user to own the socket.
10550 Defaults to @samp{""}.
10553 @deftypevr {@code{fifo-listener-configuration} parameter} string group
10554 The group to own the socket.
10555 Defaults to @samp{""}.
10559 Available @code{inet-listener-configuration} fields are:
10561 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
10562 The protocol to listen for.
10565 @deftypevr {@code{inet-listener-configuration} parameter} string address
10566 The address on which to listen, or empty for all addresses.
10567 Defaults to @samp{""}.
10570 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
10571 The port on which to listen.
10574 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
10575 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
10577 Defaults to @samp{#t}.
10582 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
10583 Number of connections to handle before starting a new process.
10584 Typically the only useful values are 0 (unlimited) or 1. 1 is more
10585 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
10586 Defaults to @samp{1}.
10589 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
10590 Number of processes to always keep waiting for more connections.
10591 Defaults to @samp{0}.
10594 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
10595 If you set @samp{service-count 0}, you probably need to grow
10597 Defaults to @samp{256000000}.
10602 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
10603 Dict configuration, as created by the @code{dict-configuration}
10606 Available @code{dict-configuration} fields are:
10608 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
10609 A list of key-value pairs that this dict should hold.
10610 Defaults to @samp{()}.
10615 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
10616 A list of passdb configurations, each one created by the
10617 @code{passdb-configuration} constructor.
10619 Available @code{passdb-configuration} fields are:
10621 @deftypevr {@code{passdb-configuration} parameter} string driver
10622 The driver that the passdb should use. Valid values include
10623 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
10625 Defaults to @samp{"pam"}.
10628 @deftypevr {@code{passdb-configuration} parameter} free-form-args args
10629 A list of key-value args to the passdb driver.
10630 Defaults to @samp{()}.
10635 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
10636 List of userdb configurations, each one created by the
10637 @code{userdb-configuration} constructor.
10639 Available @code{userdb-configuration} fields are:
10641 @deftypevr {@code{userdb-configuration} parameter} string driver
10642 The driver that the userdb should use. Valid values include
10643 @samp{passwd} and @samp{static}.
10644 Defaults to @samp{"passwd"}.
10647 @deftypevr {@code{userdb-configuration} parameter} free-form-args args
10648 A list of key-value args to the userdb driver.
10649 Defaults to @samp{()}.
10652 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
10653 Override fields from passwd.
10654 Defaults to @samp{()}.
10659 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
10660 Plug-in configuration, created by the @code{plugin-configuration}
10664 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
10665 List of namespaces. Each item in the list is created by the
10666 @code{namespace-configuration} constructor.
10668 Available @code{namespace-configuration} fields are:
10670 @deftypevr {@code{namespace-configuration} parameter} string name
10671 Name for this namespace.
10674 @deftypevr {@code{namespace-configuration} parameter} string type
10675 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
10676 Defaults to @samp{"private"}.
10679 @deftypevr {@code{namespace-configuration} parameter} string separator
10680 Hierarchy separator to use. You should use the same separator for
10681 all namespaces or some clients get confused. @samp{/} is usually a good
10682 one. The default however depends on the underlying mail storage
10684 Defaults to @samp{""}.
10687 @deftypevr {@code{namespace-configuration} parameter} string prefix
10688 Prefix required to access this namespace. This needs to be
10689 different for all namespaces. For example @samp{Public/}.
10690 Defaults to @samp{""}.
10693 @deftypevr {@code{namespace-configuration} parameter} string location
10694 Physical location of the mailbox. This is in the same format as
10695 mail_location, which is also the default for it.
10696 Defaults to @samp{""}.
10699 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
10700 There can be only one INBOX, and this setting defines which
10702 Defaults to @samp{#f}.
10705 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
10706 If namespace is hidden, it's not advertised to clients via NAMESPACE
10707 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
10708 useful when converting from another server with different namespaces
10709 which you want to deprecate but still keep working. For example you can
10710 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
10712 Defaults to @samp{#f}.
10715 @deftypevr {@code{namespace-configuration} parameter} boolean list?
10716 Show the mailboxes under this namespace with the LIST command. This
10717 makes the namespace visible for clients that do not support the NAMESPACE
10718 extension. The special @code{children} value lists child mailboxes, but
10719 hides the namespace prefix.
10720 Defaults to @samp{#t}.
10723 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
10724 Namespace handles its own subscriptions. If set to @code{#f}, the
10725 parent namespace handles them. The empty prefix should always have this
10727 Defaults to @samp{#t}.
10730 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
10731 List of predefined mailboxes in this namespace.
10732 Defaults to @samp{()}.
10734 Available @code{mailbox-configuration} fields are:
10736 @deftypevr {@code{mailbox-configuration} parameter} string name
10737 Name for this mailbox.
10740 @deftypevr {@code{mailbox-configuration} parameter} string auto
10741 @samp{create} will automatically create this mailbox.
10742 @samp{subscribe} will both create and subscribe to the mailbox.
10743 Defaults to @samp{"no"}.
10746 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
10747 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
10748 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
10749 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
10750 Defaults to @samp{()}.
10757 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
10758 Base directory where to store runtime data.
10759 Defaults to @samp{"/var/run/dovecot/"}.
10762 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
10763 Greeting message for clients.
10764 Defaults to @samp{"Dovecot ready."}.
10767 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
10768 List of trusted network ranges. Connections from these IPs are
10769 allowed to override their IP addresses and ports (for logging and for
10770 authentication checks). @samp{disable-plaintext-auth} is also ignored
10771 for these networks. Typically you would specify your IMAP proxy servers
10773 Defaults to @samp{()}.
10776 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
10777 List of login access check sockets (e.g. tcpwrap).
10778 Defaults to @samp{()}.
10781 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
10782 Show more verbose process titles (in ps). Currently shows user name
10783 and IP address. Useful for seeing who is actually using the IMAP
10784 processes (e.g. shared mailboxes or if the same uid is used for multiple
10786 Defaults to @samp{#f}.
10789 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
10790 Should all processes be killed when Dovecot master process shuts down.
10791 Setting this to @code{#f} means that Dovecot can be upgraded without
10792 forcing existing client connections to close (although that could also
10793 be a problem if the upgrade is e.g. due to a security fix).
10794 Defaults to @samp{#t}.
10797 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
10798 If non-zero, run mail commands via this many connections to doveadm
10799 server, instead of running them directly in the same process.
10800 Defaults to @samp{0}.
10803 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
10804 UNIX socket or host:port used for connecting to doveadm server.
10805 Defaults to @samp{"doveadm-server"}.
10808 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
10809 List of environment variables that are preserved on Dovecot startup
10810 and passed down to all of its child processes. You can also give
10811 key=value pairs to always set specific settings.
10814 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
10815 Disable LOGIN command and all other plaintext authentications unless
10816 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
10817 matches the local IP (i.e. you're connecting from the same computer),
10818 the connection is considered secure and plaintext authentication is
10819 allowed. See also ssl=required setting.
10820 Defaults to @samp{#t}.
10823 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
10824 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
10825 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
10826 for caching to be used.
10827 Defaults to @samp{0}.
10830 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
10831 Time to live for cached data. After TTL expires the cached record
10832 is no longer used, *except* if the main database lookup returns internal
10833 failure. We also try to handle password changes automatically: If
10834 user's previous authentication was successful, but this one wasn't, the
10835 cache isn't used. For now this works only with plaintext
10837 Defaults to @samp{"1 hour"}.
10840 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
10841 TTL for negative hits (user not found, password mismatch).
10842 0 disables caching them completely.
10843 Defaults to @samp{"1 hour"}.
10846 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
10847 List of realms for SASL authentication mechanisms that need them.
10848 You can leave it empty if you don't want to support multiple realms.
10849 Many clients simply use the first one listed here, so keep the default
10851 Defaults to @samp{()}.
10854 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
10855 Default realm/domain to use if none was specified. This is used for
10856 both SASL realms and appending @@domain to username in plaintext
10858 Defaults to @samp{""}.
10861 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
10862 List of allowed characters in username. If the user-given username
10863 contains a character not listed in here, the login automatically fails.
10864 This is just an extra check to make sure user can't exploit any
10865 potential quote escaping vulnerabilities with SQL/LDAP databases. If
10866 you want to allow all characters, set this value to empty.
10867 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
10870 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
10871 Username character translations before it's looked up from
10872 databases. The value contains series of from -> to characters. For
10873 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
10874 translated to @samp{@@}.
10875 Defaults to @samp{""}.
10878 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
10879 Username formatting before it's looked up from databases. You can
10880 use the standard variables here, e.g. %Lu would lowercase the username,
10881 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
10882 change the @samp{@@} into @samp{-AT-}. This translation is done after
10883 @samp{auth-username-translation} changes.
10884 Defaults to @samp{"%Lu"}.
10887 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
10888 If you want to allow master users to log in by specifying the master
10889 username within the normal username string (i.e. not using SASL
10890 mechanism's support for it), you can specify the separator character
10891 here. The format is then <username><separator><master username>.
10892 UW-IMAP uses @samp{*} as the separator, so that could be a good
10894 Defaults to @samp{""}.
10897 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
10898 Username to use for users logging in with ANONYMOUS SASL
10900 Defaults to @samp{"anonymous"}.
10903 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
10904 Maximum number of dovecot-auth worker processes. They're used to
10905 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
10906 They're automatically created and destroyed as needed.
10907 Defaults to @samp{30}.
10910 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
10911 Host name to use in GSSAPI principal names. The default is to use
10912 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
10913 allow all keytab entries.
10914 Defaults to @samp{""}.
10917 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
10918 Kerberos keytab to use for the GSSAPI mechanism. Will use the
10919 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
10920 need to change the auth service to run as root to be able to read this
10922 Defaults to @samp{""}.
10925 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
10926 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
10927 and @samp{ntlm-auth} helper.
10928 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
10929 Defaults to @samp{#f}.
10932 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
10933 Path for Samba's @samp{ntlm-auth} helper binary.
10934 Defaults to @samp{"/usr/bin/ntlm_auth"}.
10937 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
10938 Time to delay before replying to failed authentications.
10939 Defaults to @samp{"2 secs"}.
10942 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
10943 Require a valid SSL client certificate or the authentication
10945 Defaults to @samp{#f}.
10948 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
10949 Take the username from client's SSL certificate, using
10950 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
10952 Defaults to @samp{#f}.
10955 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
10956 List of wanted authentication mechanisms. Supported mechanisms are:
10957 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
10958 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
10959 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
10960 @samp{disable-plaintext-auth} setting.
10963 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
10964 List of IPs or hostnames to all director servers, including ourself.
10965 Ports can be specified as ip:port. The default port is the same as what
10966 director service's @samp{inet-listener} is using.
10967 Defaults to @samp{()}.
10970 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
10971 List of IPs or hostnames to all backend mail servers. Ranges are
10972 allowed too, like 10.0.0.10-10.0.0.30.
10973 Defaults to @samp{()}.
10976 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
10977 How long to redirect users to a specific server after it no longer
10978 has any connections.
10979 Defaults to @samp{"15 min"}.
10982 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
10983 TCP/IP port that accepts doveadm connections (instead of director
10984 connections) If you enable this, you'll also need to add
10985 @samp{inet-listener} for the port.
10986 Defaults to @samp{0}.
10989 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
10990 How the username is translated before being hashed. Useful values
10991 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
10992 are shared within domain.
10993 Defaults to @samp{"%Lu"}.
10996 @deftypevr {@code{dovecot-configuration} parameter} string log-path
10997 Log file to use for error messages. @samp{syslog} logs to syslog,
10998 @samp{/dev/stderr} logs to stderr.
10999 Defaults to @samp{"syslog"}.
11002 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
11003 Log file to use for informational messages. Defaults to
11005 Defaults to @samp{""}.
11008 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
11009 Log file to use for debug messages. Defaults to
11010 @samp{info-log-path}.
11011 Defaults to @samp{""}.
11014 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
11015 Syslog facility to use if you're logging to syslog. Usually if you
11016 don't want to use @samp{mail}, you'll use local0..local7. Also other
11017 standard facilities are supported.
11018 Defaults to @samp{"mail"}.
11021 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
11022 Log unsuccessful authentication attempts and the reasons why they
11024 Defaults to @samp{#f}.
11027 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
11028 In case of password mismatches, log the attempted password. Valid
11029 values are no, plain and sha1. sha1 can be useful for detecting brute
11030 force password attempts vs. user simply trying the same password over
11031 and over again. You can also truncate the value to n chars by appending
11032 ":n" (e.g. sha1:6).
11033 Defaults to @samp{#f}.
11036 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
11037 Even more verbose logging for debugging purposes. Shows for example
11039 Defaults to @samp{#f}.
11042 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
11043 In case of password mismatches, log the passwords and used scheme so
11044 the problem can be debugged. Enabling this also enables
11046 Defaults to @samp{#f}.
11049 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
11050 Enable mail process debugging. This can help you figure out why
11051 Dovecot isn't finding your mails.
11052 Defaults to @samp{#f}.
11055 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
11056 Show protocol level SSL errors.
11057 Defaults to @samp{#f}.
11060 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
11061 Prefix for each line written to log file. % codes are in
11062 strftime(3) format.
11063 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
11066 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
11067 List of elements we want to log. The elements which have a
11068 non-empty variable value are joined together to form a comma-separated
11072 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
11073 Login log format. %s contains @samp{login-log-format-elements}
11074 string, %$ contains the data we want to log.
11075 Defaults to @samp{"%$: %s"}.
11078 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
11079 Log prefix for mail processes. See doc/wiki/Variables.txt for list
11080 of possible variables you can use.
11081 Defaults to @samp{"\"%s(%u): \""}.
11084 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
11085 Format to use for logging mail deliveries. You can use variables:
11088 Delivery status message (e.g. @samp{saved to INBOX})
11100 Defaults to @samp{"msgid=%m: %$"}.
11103 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
11104 Location for users' mailboxes. The default is empty, which means
11105 that Dovecot tries to find the mailboxes automatically. This won't work
11106 if the user doesn't yet have any mail, so you should explicitly tell
11107 Dovecot the full location.
11109 If you're using mbox, giving a path to the INBOX
11110 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
11111 where the other mailboxes are kept. This is called the "root mail
11112 directory", and it must be the first path given in the
11113 @samp{mail-location} setting.
11115 There are a few special variables you can use, eg.:
11121 user part in user@@domain, same as %u if there's no domain
11123 domain part in user@@domain, empty if there's no domain
11128 See doc/wiki/Variables.txt for full list. Some examples:
11130 @item maildir:~/Maildir
11131 @item mbox:~/mail:INBOX=/var/mail/%u
11132 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
11134 Defaults to @samp{""}.
11137 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
11138 System user and group used to access mails. If you use multiple,
11139 userdb can override these by returning uid or gid fields. You can use
11140 either numbers or names. <doc/wiki/UserIds.txt>.
11141 Defaults to @samp{""}.
11144 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
11146 Defaults to @samp{""}.
11149 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
11150 Group to enable temporarily for privileged operations. Currently
11151 this is used only with INBOX when either its initial creation or
11152 dotlocking fails. Typically this is set to "mail" to give access to
11154 Defaults to @samp{""}.
11157 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
11158 Grant access to these supplementary groups for mail processes.
11159 Typically these are used to set up access to shared mailboxes. Note
11160 that it may be dangerous to set these if users can create
11161 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
11162 could allow a user to delete others' mailboxes, or ln -s
11163 /secret/shared/box ~/mail/mybox would allow reading it).
11164 Defaults to @samp{""}.
11167 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
11168 Allow full file system access to clients. There's no access checks
11169 other than what the operating system does for the active UID/GID. It
11170 works with both maildir and mboxes, allowing you to prefix mailboxes
11171 names with e.g. /path/ or ~user/.
11172 Defaults to @samp{#f}.
11175 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
11176 Don't use mmap() at all. This is required if you store indexes to
11177 shared file systems (NFS or clustered file system).
11178 Defaults to @samp{#f}.
11181 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
11182 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
11183 supports @samp{O_EXCL} since version 3, so this should be safe to use
11184 nowadays by default.
11185 Defaults to @samp{#t}.
11188 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
11189 When to use fsync() or fdatasync() calls:
11192 Whenever necessary to avoid losing important data
11194 Useful with e.g. NFS when write()s are delayed
11196 Never use it (best performance, but crashes can lose data).
11198 Defaults to @samp{"optimized"}.
11201 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
11202 Mail storage exists in NFS. Set this to yes to make Dovecot flush
11203 NFS caches whenever needed. If you're using only a single mail server
11205 Defaults to @samp{#f}.
11208 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
11209 Mail index files also exist in NFS. Setting this to yes requires
11210 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
11211 Defaults to @samp{#f}.
11214 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
11215 Locking method for index files. Alternatives are fcntl, flock and
11216 dotlock. Dotlocking uses some tricks which may create more disk I/O
11217 than other locking methods. NFS users: flock doesn't work, remember to
11218 change @samp{mmap-disable}.
11219 Defaults to @samp{"fcntl"}.
11222 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
11223 Directory in which LDA/LMTP temporarily stores incoming mails >128
11225 Defaults to @samp{"/tmp"}.
11228 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
11229 Valid UID range for users. This is mostly to make sure that users can't
11230 log in as daemons or other system users. Note that denying root logins is
11231 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
11233 Defaults to @samp{500}.
11236 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
11238 Defaults to @samp{0}.
11241 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
11242 Valid GID range for users. Users having non-valid GID as primary group ID
11243 aren't allowed to log in. If user belongs to supplementary groups with
11244 non-valid GIDs, those groups are not set.
11245 Defaults to @samp{1}.
11248 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
11250 Defaults to @samp{0}.
11253 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
11254 Maximum allowed length for mail keyword name. It's only forced when
11255 trying to create new keywords.
11256 Defaults to @samp{50}.
11259 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
11260 List of directories under which chrooting is allowed for mail
11261 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
11262 too). This setting doesn't affect @samp{login-chroot}
11263 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
11264 "/./" in home dirs are ignored. WARNING: Never add directories here
11265 which local users can modify, that may lead to root exploit. Usually
11266 this should be done only if you don't allow shell access for users.
11267 <doc/wiki/Chrooting.txt>.
11268 Defaults to @samp{()}.
11271 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
11272 Default chroot directory for mail processes. This can be overridden
11273 for specific users in user database by giving /./ in user's home
11274 directory (e.g. /home/./user chroots into /home). Note that usually
11275 there is no real need to do chrooting, Dovecot doesn't allow users to
11276 access files outside their mail directory anyway. If your home
11277 directories are prefixed with the chroot directory, append "/." to
11278 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
11279 Defaults to @samp{""}.
11282 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
11283 UNIX socket path to master authentication server to find users.
11284 This is used by imap (for shared users) and lda.
11285 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11288 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
11289 Directory where to look up mail plugins.
11290 Defaults to @samp{"/usr/lib/dovecot"}.
11293 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
11294 List of plugins to load for all services. Plugins specific to IMAP,
11295 LDA, etc. are added to this list in their own .conf files.
11296 Defaults to @samp{()}.
11299 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
11300 The minimum number of mails in a mailbox before updates are done to
11301 cache file. This allows optimizing Dovecot's behavior to do less disk
11302 writes at the cost of more disk reads.
11303 Defaults to @samp{0}.
11306 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
11307 When IDLE command is running, mailbox is checked once in a while to
11308 see if there are any new mails or other changes. This setting defines
11309 the minimum time to wait between those checks. Dovecot can also use
11310 dnotify, inotify and kqueue to find out immediately when changes
11312 Defaults to @samp{"30 secs"}.
11315 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
11316 Save mails with CR+LF instead of plain LF. This makes sending those
11317 mails take less CPU, especially with sendfile() syscall with Linux and
11318 FreeBSD. But it also creates a bit more disk I/O which may just make it
11319 slower. Also note that if other software reads the mboxes/maildirs,
11320 they may handle the extra CRs wrong and cause problems.
11321 Defaults to @samp{#f}.
11324 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
11325 By default LIST command returns all entries in maildir beginning
11326 with a dot. Enabling this option makes Dovecot return only entries
11327 which are directories. This is done by stat()ing each entry, so it
11328 causes more disk I/O.
11329 (For systems setting struct @samp{dirent->d_type} this check is free
11330 and it's done always regardless of this setting).
11331 Defaults to @samp{#f}.
11334 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
11335 When copying a message, do it with hard links whenever possible.
11336 This makes the performance much better, and it's unlikely to have any
11338 Defaults to @samp{#t}.
11341 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
11342 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
11343 directory only when its mtime changes unexpectedly or when we can't find
11344 the mail otherwise.
11345 Defaults to @samp{#f}.
11348 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
11349 Which locking methods to use for locking mbox. There are four
11354 Create <mailbox>.lock file. This is the oldest and most NFS-safe
11355 solution. If you want to use /var/mail/ like directory, the users will
11356 need write access to that directory.
11358 Same as dotlock, but if it fails because of permissions or because there
11359 isn't enough disk space, just skip it.
11361 Use this if possible. Works with NFS too if lockd is used.
11363 May not exist in all systems. Doesn't work with NFS.
11365 May not exist in all systems. Doesn't work with NFS.
11368 You can use multiple locking methods; if you do the order they're declared
11369 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
11370 locking methods as well. Some operating systems don't allow using some of
11371 them simultaneously.
11374 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
11378 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
11379 Maximum time to wait for lock (all of them) before aborting.
11380 Defaults to @samp{"5 mins"}.
11383 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
11384 If dotlock exists but the mailbox isn't modified in any way,
11385 override the lock file after this much time.
11386 Defaults to @samp{"2 mins"}.
11389 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
11390 When mbox changes unexpectedly we have to fully read it to find out
11391 what changed. If the mbox is large this can take a long time. Since
11392 the change is usually just a newly appended mail, it'd be faster to
11393 simply read the new mails. If this setting is enabled, Dovecot does
11394 this but still safely fallbacks to re-reading the whole mbox file
11395 whenever something in mbox isn't how it's expected to be. The only real
11396 downside to this setting is that if some other MUA changes message
11397 flags, Dovecot doesn't notice it immediately. Note that a full sync is
11398 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
11399 Defaults to @samp{#t}.
11402 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
11403 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
11404 EXAMINE, EXPUNGE or CHECK commands. If this is set,
11405 @samp{mbox-dirty-syncs} is ignored.
11406 Defaults to @samp{#f}.
11409 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
11410 Delay writing mbox headers until doing a full write sync (EXPUNGE
11411 and CHECK commands and when closing the mailbox). This is especially
11412 useful for POP3 where clients often delete all mails. The downside is
11413 that our changes aren't immediately visible to other MUAs.
11414 Defaults to @samp{#t}.
11417 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
11418 If mbox size is smaller than this (e.g. 100k), don't write index
11419 files. If an index file already exists it's still read, just not
11421 Defaults to @samp{0}.
11424 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
11425 Maximum dbox file size until it's rotated.
11426 Defaults to @samp{2000000}.
11429 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
11430 Maximum dbox file age until it's rotated. Typically in days. Day
11431 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
11433 Defaults to @samp{"1d"}.
11436 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
11437 When creating new mdbox files, immediately preallocate their size to
11438 @samp{mdbox-rotate-size}. This setting currently works only in Linux
11439 with some file systems (ext4, xfs).
11440 Defaults to @samp{#f}.
11443 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
11444 sdbox and mdbox support saving mail attachments to external files,
11445 which also allows single instance storage for them. Other backends
11446 don't support this for now.
11448 WARNING: This feature hasn't been tested much yet. Use at your own risk.
11450 Directory root where to store mail attachments. Disabled, if empty.
11451 Defaults to @samp{""}.
11454 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
11455 Attachments smaller than this aren't saved externally. It's also
11456 possible to write a plugin to disable saving specific attachments
11458 Defaults to @samp{128000}.
11461 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
11462 File system backend to use for saving attachments:
11465 No SiS done by Dovecot (but this might help FS's own deduplication)
11467 SiS with immediate byte-by-byte comparison during saving
11468 @item sis-queue posix
11469 SiS with delayed comparison and deduplication.
11471 Defaults to @samp{"sis posix"}.
11474 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
11475 Hash format to use in attachment filenames. You can add any text and
11476 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
11477 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
11478 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
11479 Defaults to @samp{"%@{sha1@}"}.
11482 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
11484 Defaults to @samp{100}.
11487 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
11489 Defaults to @samp{1000}.
11492 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
11493 Default VSZ (virtual memory size) limit for service processes.
11494 This is mainly intended to catch and kill processes that leak memory
11495 before they eat up everything.
11496 Defaults to @samp{256000000}.
11499 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
11500 Login user is internally used by login processes. This is the most
11501 untrusted user in Dovecot system. It shouldn't have access to anything
11503 Defaults to @samp{"dovenull"}.
11506 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
11507 Internal user is used by unprivileged processes. It should be
11508 separate from login user, so that login processes can't disturb other
11510 Defaults to @samp{"dovecot"}.
11513 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
11514 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
11515 Defaults to @samp{"required"}.
11518 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
11519 PEM encoded X.509 SSL/TLS certificate (public key).
11520 Defaults to @samp{"</etc/dovecot/default.pem"}.
11523 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
11524 PEM encoded SSL/TLS private key. The key is opened before
11525 dropping root privileges, so keep the key file unreadable by anyone but
11527 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
11530 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
11531 If key file is password protected, give the password here.
11532 Alternatively give it when starting dovecot with -p parameter. Since
11533 this file is often world-readable, you may want to place this setting
11534 instead to a different.
11535 Defaults to @samp{""}.
11538 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
11539 PEM encoded trusted certificate authority. Set this only if you
11540 intend to use @samp{ssl-verify-client-cert? #t}. The file should
11541 contain the CA certificate(s) followed by the matching
11542 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
11543 Defaults to @samp{""}.
11546 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
11547 Require that CRL check succeeds for client certificates.
11548 Defaults to @samp{#t}.
11551 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
11552 Request client to send a certificate. If you also want to require
11553 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
11554 Defaults to @samp{#f}.
11557 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
11558 Which field from certificate to use for username. commonName and
11559 x500UniqueIdentifier are the usual choices. You'll also need to set
11560 @samp{auth-ssl-username-from-cert? #t}.
11561 Defaults to @samp{"commonName"}.
11564 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
11565 How often to regenerate the SSL parameters file. Generation is
11566 quite CPU intensive operation. The value is in hours, 0 disables
11567 regeneration entirely.
11568 Defaults to @samp{168}.
11571 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
11572 SSL protocols to use.
11573 Defaults to @samp{"!SSLv2"}.
11576 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
11577 SSL ciphers to use.
11578 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
11581 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
11582 SSL crypto device to use, for valid values run "openssl engine".
11583 Defaults to @samp{""}.
11586 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
11587 Address to use when sending rejection mails.
11588 %d expands to recipient domain.
11589 Defaults to @samp{"postmaster@@%d"}.
11592 @deftypevr {@code{dovecot-configuration} parameter} string hostname
11593 Hostname to use in various parts of sent mails (e.g. in Message-Id)
11594 and in LMTP replies. Default is the system's real hostname@@domain.
11595 Defaults to @samp{""}.
11598 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
11599 If user is over quota, return with temporary failure instead of
11601 Defaults to @samp{#f}.
11604 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
11605 Binary to use for sending mails.
11606 Defaults to @samp{"/usr/sbin/sendmail"}.
11609 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
11610 If non-empty, send mails via this SMTP host[:port] instead of
11612 Defaults to @samp{""}.
11615 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
11616 Subject: header to use for rejection mails. You can use the same
11617 variables as for @samp{rejection-reason} below.
11618 Defaults to @samp{"Rejected: %s"}.
11621 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
11622 Human readable error message for rejection mails. You can use
11635 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
11638 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
11639 Delimiter character between local-part and detail in email
11641 Defaults to @samp{"+"}.
11644 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
11645 Header where the original recipient address (SMTP's RCPT TO:
11646 address) is taken from if not available elsewhere. With dovecot-lda -a
11647 parameter overrides this. A commonly used header for this is
11649 Defaults to @samp{""}.
11652 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
11653 Should saving a mail to a nonexistent mailbox automatically create
11655 Defaults to @samp{#f}.
11658 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
11659 Should automatically created mailboxes be also automatically
11661 Defaults to @samp{#f}.
11664 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
11665 Maximum IMAP command line length. Some clients generate very long
11666 command lines with huge mailboxes, so you may need to raise this if you
11667 get "Too long argument" or "IMAP command line too large" errors
11669 Defaults to @samp{64000}.
11672 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
11673 IMAP logout format string:
11676 total number of bytes read from client
11678 total number of bytes sent to client.
11680 Defaults to @samp{"in=%i out=%o"}.
11683 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
11684 Override the IMAP CAPABILITY response. If the value begins with '+',
11685 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
11686 Defaults to @samp{""}.
11689 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
11690 How long to wait between "OK Still here" notifications when client
11692 Defaults to @samp{"2 mins"}.
11695 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
11696 ID field names and values to send to clients. Using * as the value
11697 makes Dovecot use the default value. The following fields have default
11698 values currently: name, version, os, os-version, support-url,
11700 Defaults to @samp{""}.
11703 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
11704 ID fields sent by client to log. * means everything.
11705 Defaults to @samp{""}.
11708 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
11709 Workarounds for various client bugs:
11712 @item delay-newmail
11713 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
11714 CHECK commands. Some clients ignore them otherwise, for example OSX
11715 Mail (<v2.1). Outlook Express breaks more badly though, without this it
11716 may show user "Message no longer in server" errors. Note that OE6
11717 still breaks even with this workaround if synchronization is set to
11720 @item tb-extra-mailbox-sep
11721 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
11722 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
11723 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
11725 @item tb-lsub-flags
11726 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
11727 This makes Thunderbird realize they aren't selectable and show them
11728 greyed out, instead of only later giving "not selectable" popup error.
11730 Defaults to @samp{()}.
11733 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
11734 Host allowed in URLAUTH URLs sent by client. "*" allows all.
11735 Defaults to @samp{""}.
11739 Whew! Lots of configuration options. The nice thing about it though is
11740 that GuixSD has a complete interface to Dovecot's configuration
11741 language. This allows not only a nice way to declare configurations,
11742 but also offers reflective capabilities as well: users can write code to
11743 inspect and transform configurations from within Scheme.
11745 However, it could be that you just want to get a @code{dovecot.conf} up
11746 and running. In that case, you can pass an
11747 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
11748 @code{dovecot-service}. As its name indicates, an opaque configuration
11749 does not have easy reflective capabilities.
11751 Available @code{opaque-dovecot-configuration} fields are:
11753 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
11754 The dovecot package.
11757 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
11758 The contents of the @code{dovecot.conf}, as a string.
11761 For example, if your @code{dovecot.conf} is just the empty string, you
11762 could instantiate a dovecot service like this:
11765 (dovecot-service #:config
11766 (opaque-dovecot-configuration
11770 @subsubheading OpenSMTPD Service
11772 @deffn {Scheme Variable} opensmtpd-service-type
11773 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
11774 service, whose value should be an @code{opensmtpd-configuration} object
11775 as in this example:
11778 (service opensmtpd-service-type
11779 (opensmtpd-configuration
11780 (config-file (local-file "./my-smtpd.conf"))))
11784 @deftp {Data Type} opensmtpd-configuration
11785 Data type regresenting the configuration of opensmtpd.
11788 @item @code{package} (default: @var{opensmtpd})
11789 Package object of the OpenSMTPD SMTP server.
11791 @item @code{config-file} (default: @var{%default-opensmtpd-file})
11792 File-like object of the OpenSMTPD configuration file to use. By default
11793 it listens on the loopback network interface, and allows for mail from
11794 users and daemons on the local machine, as well as permitting email to
11795 remote servers. Run @command{man smtpd.conf} for more information.
11800 @node Messaging Services
11801 @subsubsection Messaging Services
11806 The @code{(gnu services messaging)} module provides Guix service
11807 definitions for messaging services: currently only Prosody is supported.
11809 @subsubheading Prosody Service
11811 @deffn {Scheme Variable} prosody-service-type
11812 This is the type for the @uref{http://prosody.im, Prosody XMPP
11813 communication server}. Its value must be a @code{prosody-configuration}
11814 record as in this example:
11817 (service prosody-service-type
11818 (prosody-configuration
11819 (modules-enabled (cons "groups" %default-modules-enabled))
11822 (int-component-configuration
11823 (hostname "conference.example.net")
11825 (mod-muc (mod-muc-configuration)))))
11828 (virtualhost-configuration
11829 (domain "example.net"))))))
11832 See below for details about @code{prosody-configuration}.
11836 By default, Prosody does not need much configuration. Only one
11837 @code{virtualhosts} field is needed: it specifies the domain you wish
11840 Prosodyctl will help you generate X.509 certificates and keys:
11843 prosodyctl cert request example.net
11846 The available configuration parameters follow. Each parameter
11847 definition is preceded by its type; for example, @samp{string-list foo}
11848 indicates that the @code{foo} parameter should be specified as a list of
11849 strings. Types starting with @code{maybe-} denote parameters that won't
11850 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
11852 There is also a way to specify the configuration as a string, if you
11853 have an old @code{prosody.cfg.lua} file that you want to port over from
11854 some other system; see the end for more details.
11856 @c The following documentation was initially generated by
11857 @c (generate-documentation) in (gnu services messaging). Manually maintained
11858 @c documentation is better, so we shouldn't hesitate to edit below as
11859 @c needed. However if the change you want to make to this documentation
11860 @c can be done in an automated way, it's probably easier to change
11861 @c (generate-documentation) than to make it below and have to deal with
11862 @c the churn as Prosody updates.
11864 Available @code{prosody-configuration} fields are:
11866 @deftypevr {@code{prosody-configuration} parameter} package prosody
11867 The Prosody package.
11870 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
11871 Location of the Prosody data storage directory. See
11872 @url{http://prosody.im/doc/configure}.
11873 Defaults to @samp{"/var/lib/prosody"}.
11876 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
11877 Additional plugin directories. They are searched in all the specified
11878 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
11879 Defaults to @samp{()}.
11882 @deftypevr {@code{prosody-configuration} parameter} string-list admins
11883 This is a list of accounts that are admins for the server. Note that you
11884 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
11885 @url{http://prosody.im/doc/creating_accounts}.
11886 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
11887 Defaults to @samp{()}.
11890 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
11891 Enable use of libevent for better performance under high load. See
11892 @url{http://prosody.im/doc/libevent}.
11893 Defaults to @samp{#f}.
11896 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
11897 This is the list of modules Prosody will load on startup. It looks for
11898 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
11899 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
11900 Defaults to @samp{%default-modules-enabled}.
11903 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
11904 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
11905 should you want to disable them then add them to this list.
11906 Defaults to @samp{()}.
11909 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
11910 Path to a text file where the shared groups are defined. If this path is
11911 empty then @samp{mod_groups} does nothing. See
11912 @url{http://prosody.im/doc/modules/mod_groups}.
11913 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
11916 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
11917 Disable account creation by default, for security. See
11918 @url{http://prosody.im/doc/creating_accounts}.
11919 Defaults to @samp{#f}.
11922 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
11923 These are the SSL/TLS-related settings. Most of them are disabled so to
11924 use Prosody's defaults. If you do not completely understand these options, do
11925 not add them to your config, it is easy to lower the security of your server
11926 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
11928 Available @code{ssl-configuration} fields are:
11930 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
11931 This determines what handshake to use.
11934 @deftypevr {@code{ssl-configuration} parameter} file-name key
11935 Path to your private key file, relative to @code{/etc/prosody}.
11936 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
11939 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
11940 Path to your certificate file, relative to @code{/etc/prosody}.
11941 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
11944 @deftypevr {@code{ssl-configuration} parameter} file-name capath
11945 Path to directory containing root certificates that you wish Prosody to
11946 trust when verifying the certificates of remote servers.
11947 Defaults to @samp{"/etc/ssl/certs"}.
11950 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
11951 Path to a file containing root certificates that you wish Prosody to trust.
11952 Similar to @code{capath} but with all certificates concatenated together.
11955 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
11956 A list of verification options (these mostly map to OpenSSL's
11957 @code{set_verify()} flags).
11960 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
11961 A list of general options relating to SSL/TLS. These map to OpenSSL's
11962 @code{set_options()}. For a full list of options available in LuaSec, see the
11966 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
11967 How long a chain of certificate authorities to check when looking for a
11968 trusted root certificate.
11971 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
11972 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
11973 clients, and in what order.
11976 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
11977 A path to a file containing parameters for Diffie-Hellman key exchange. You
11978 can create such a file with:
11979 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
11982 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
11983 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
11984 @samp{"secp384r1"}.
11987 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
11988 A list of "extra" verification options.
11991 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
11992 Password for encrypted private keys.
11997 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
11998 Whether to force all client-to-server connections to be encrypted or not.
11999 See @url{http://prosody.im/doc/modules/mod_tls}.
12000 Defaults to @samp{#f}.
12003 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
12004 Whether to force all server-to-server connections to be encrypted or not.
12005 See @url{http://prosody.im/doc/modules/mod_tls}.
12006 Defaults to @samp{#f}.
12009 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
12010 Whether to require encryption and certificate authentication. This
12011 provides ideal security, but requires servers you communicate with to support
12012 encryption AND present valid, trusted certificates. See
12013 @url{http://prosody.im/doc/s2s#security}.
12014 Defaults to @samp{#f}.
12017 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
12018 Many servers don't support encryption or have invalid or self-signed
12019 certificates. You can list domains here that will not be required to
12020 authenticate using certificates. They will be authenticated using DNS. See
12021 @url{http://prosody.im/doc/s2s#security}.
12022 Defaults to @samp{()}.
12025 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
12026 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
12027 valid certificates for some domains by specifying a list here. See
12028 @url{http://prosody.im/doc/s2s#security}.
12029 Defaults to @samp{()}.
12032 @deftypevr {@code{prosody-configuration} parameter} string authentication
12033 Select the authentication backend to use. The default provider stores
12034 passwords in plaintext and uses Prosody's configured data storage to store the
12035 authentication data. If you do not trust your server please see
12036 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
12037 about using the hashed backend. See also
12038 @url{http://prosody.im/doc/authentication}
12039 Defaults to @samp{"internal_plain"}.
12042 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
12043 Set logging options. Advanced logging configuration is not yet supported
12044 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
12045 Defaults to @samp{"*syslog"}.
12048 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
12049 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
12050 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
12053 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
12054 A host in Prosody is a domain on which user accounts can be created. For
12055 example if you want your users to have addresses like
12056 @samp{"john.smith@@example.com"} then you need to add a host
12057 @samp{"example.com"}. All options in this list will apply only to this host.
12059 Note: the name "virtual" host is used in configuration to avoid confusion with
12060 the actual physical host that Prosody is installed on. A single Prosody
12061 instance can serve many domains, each one defined as a VirtualHost entry in
12062 Prosody's configuration. Conversely a server that hosts a single domain would
12063 have just one VirtualHost entry.
12065 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
12067 Available @code{virtualhost-configuration} fields are:
12069 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:
12070 @deftypevr {@code{virtualhost-configuration} parameter} string domain
12071 Domain you wish Prosody to serve.
12076 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
12077 Components are extra services on a server which are available to clients,
12078 usually on a subdomain of the main server (such as
12079 @samp{"mycomponent.example.com"}). Example components might be chatroom
12080 servers, user directories, or gateways to other protocols.
12082 Internal components are implemented with Prosody-specific plugins. To add an
12083 internal component, you simply fill the hostname field, and the plugin you wish
12084 to use for the component.
12086 See @url{http://prosody.im/doc/components}.
12087 Defaults to @samp{()}.
12089 Available @code{int-component-configuration} fields are:
12091 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:
12092 @deftypevr {@code{int-component-configuration} parameter} string hostname
12093 Hostname of the component.
12096 @deftypevr {@code{int-component-configuration} parameter} string plugin
12097 Plugin you wish to use for the component.
12100 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
12101 Multi-user chat (MUC) is Prosody's module for allowing you to create
12102 hosted chatrooms/conferences for XMPP users.
12104 General information on setting up and using multi-user chatrooms can be found
12105 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
12106 which you should read if you are new to XMPP chatrooms.
12108 See also @url{http://prosody.im/doc/modules/mod_muc}.
12110 Available @code{mod-muc-configuration} fields are:
12112 @deftypevr {@code{mod-muc-configuration} parameter} string name
12113 The name to return in service discovery responses.
12114 Defaults to @samp{"Prosody Chatrooms"}.
12117 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
12118 If @samp{#t}, this will only allow admins to create new chatrooms.
12119 Otherwise anyone can create a room. The value @samp{"local"} restricts room
12120 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
12121 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
12122 restricts to service administrators only.
12123 Defaults to @samp{#f}.
12126 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
12127 Maximum number of history messages that will be sent to the member that has
12128 just joined the room.
12129 Defaults to @samp{20}.
12136 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
12137 External components use XEP-0114, which most standalone components
12138 support. To add an external component, you simply fill the hostname field. See
12139 @url{http://prosody.im/doc/components}.
12140 Defaults to @samp{()}.
12142 Available @code{ext-component-configuration} fields are:
12144 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:
12145 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
12146 Password which the component will use to log in.
12149 @deftypevr {@code{ext-component-configuration} parameter} string hostname
12150 Hostname of the component.
12155 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
12156 Port(s) Prosody listens on for component connections.
12159 @deftypevr {@code{prosody-configuration} parameter} string component-interface
12160 Interface Prosody listens on for component connections.
12161 Defaults to @samp{"127.0.0.1"}.
12164 It could be that you just want to get a @code{prosody.cfg.lua}
12165 up and running. In that case, you can pass an
12166 @code{opaque-prosody-configuration} record as the value of
12167 @code{prosody-service-type}. As its name indicates, an opaque configuration
12168 does not have easy reflective capabilities.
12169 Available @code{opaque-prosody-configuration} fields are:
12171 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
12172 The prosody package.
12175 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
12176 The contents of the @code{prosody.cfg.lua} to use.
12179 For example, if your @code{prosody.cfg.lua} is just the empty
12180 string, you could instantiate a prosody service like this:
12183 (service prosody-service-type
12184 (opaque-prosody-configuration
12185 (prosody.cfg.lua "")))
12188 @node Kerberos Services
12189 @subsubsection Kerberos Services
12192 The @code{(gnu services kerberos)} module provides services relating to
12193 the authentication protocol @dfn{Kerberos}.
12195 @subsubheading Krb5 Service
12197 Programs using a Kerberos client library normally
12198 expect a configuration file in @file{/etc/krb5.conf}.
12199 This service generates such a file from a definition provided in the
12200 operating system declaration.
12201 It does not cause any daemon to be started.
12203 No ``keytab'' files are provided by this service---you must explicitly create them.
12204 This service is known to work with the MIT client library, @code{mit-krb5}.
12205 Other implementations have not been tested.
12207 @defvr {Scheme Variable} krb5-service-type
12208 A service type for Kerberos 5 clients.
12212 Here is an example of its use:
12214 (service krb5-service-type
12215 (krb5-configuration
12216 (default-realm "EXAMPLE.COM")
12217 (allow-weak-crypto? #t)
12220 (name "EXAMPLE.COM")
12221 (admin-server "groucho.example.com")
12222 (kdc "karl.example.com"))
12225 (admin-server "kerb-admin.argrx.edu")
12226 (kdc "keys.argrx.edu"))))))
12230 This example provides a Kerberos@tie{}5 client configuration which:
12232 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
12233 of which have distinct administration servers and key distribution centers;
12234 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
12235 specified by clients;
12236 @item Accepts services which only support encryption types known to be weak.
12239 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
12240 Only the most commonly used ones are described here.
12241 For a full list, and more detailed explanation of each, see the MIT
12242 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
12246 @deftp {Data Type} krb5-realm
12247 @cindex realm, kerberos
12250 This field is a string identifying the name of the realm.
12251 A common convention is to use the fully qualified DNS name of your organization,
12252 converted to upper case.
12254 @item @code{admin-server}
12255 This field is a string identifying the host where the administration server is
12259 This field is a string identifying the key distribution center
12264 @deftp {Data Type} krb5-configuration
12267 @item @code{allow-weak-crypto?} (default: @code{#f})
12268 If this flag is @code{#t} then services which only offer encryption algorithms
12269 known to be weak will be accepted.
12271 @item @code{default-realm} (default: @code{#f})
12272 This field should be a string identifying the default Kerberos
12273 realm for the client.
12274 You should set this field to the name of your Kerberos realm.
12275 If this value is @code{#f}
12276 then a realm must be specified with every Kerberos principal when invoking programs
12277 such as @command{kinit}.
12279 @item @code{realms}
12280 This should be a non-empty list of @code{krb5-realm} objects, which clients may
12282 Normally, one of them will have a @code{name} field matching the @code{default-realm}
12288 @subsubheading PAM krb5 Service
12291 The @code{pam-krb5} service allows for login authentication and password
12292 management via Kerberos.
12293 You will need this service if you want PAM enabled applications to authenticate
12294 users using Kerberos.
12296 @defvr {Scheme Variable} pam-krb5-service-type
12297 A service type for the Kerberos 5 PAM module.
12300 @deftp {Data Type} pam-krb5-configuration
12301 Data type representing the configuration of the Kerberos 5 PAM module
12302 This type has the following parameters:
12304 @item @code{pam-krb5} (default: @code{pam-krb5})
12305 The pam-krb5 package to use.
12307 @item @code{minimum-uid} (default: @code{1000})
12308 The smallest user ID for which Kerberos authentications should be attempted.
12309 Local accounts with lower values will silently fail to authenticate.
12315 @subsubsection Web Services
12320 The @code{(gnu services web)} module provides the following service:
12322 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
12323 [#:log-directory ``/var/log/nginx''] @
12324 [#:run-directory ``/var/run/nginx''] @
12325 [#:server-list '()] @
12326 [#:upstream-list '()] @
12327 [#:config-file @code{#f}]
12329 Return a service that runs @var{nginx}, the nginx web server.
12331 The nginx daemon loads its runtime configuration from @var{config-file}.
12332 Log files are written to @var{log-directory} and temporary runtime data
12333 files are written to @var{run-directory}. For proper operation, these
12334 arguments should match what is in @var{config-file} to ensure that the
12335 directories are created when the service is activated.
12337 As an alternative to using a @var{config-file}, @var{server-list} can be
12338 used to specify the list of @dfn{server blocks} required on the host and
12339 @var{upstream-list} can be used to specify a list of @dfn{upstream
12340 blocks} to configure. For this to work, use the default value for
12345 @deffn {Scheme Variable} nginx-service-type
12346 This is type for the nginx web server.
12348 This service can be extended to add server blocks in addition to the
12349 default one, as in this example:
12352 (simple-service 'my-extra-server nginx-service-type
12353 (list (nginx-server-configuration
12355 (root "/srv/http/extra-website"))))
12359 @deftp {Data Type} nginx-server-configuration
12360 Data type representing the configuration of an nginx server block.
12361 This type has the following parameters:
12364 @item @code{http-port} (default: @code{80})
12365 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
12366 nginx should not listen for HTTP (non secure) connection for this
12367 @dfn{server block}.
12369 @item @code{https-port} (default: @code{443})
12370 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
12371 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
12373 Note that nginx can listen for HTTP and HTTPS connections in the same
12374 @dfn{server block}.
12376 @item @code{server-name} (default: @code{(list 'default)})
12377 A list of server names this server represents. @code{'default} represents the
12378 default server for connections matching no other server.
12380 @item @code{root} (default: @code{"/srv/http"})
12381 Root of the website nginx will serve.
12383 @item @code{index} (default: @code{(list "index.html")})
12384 Index files to look for when clients ask for a directory. If it cannot be found,
12385 Nginx will send the list of files in the directory.
12387 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
12388 Where to find the certificate for secure connections. Set it to @code{#f} if
12389 you don't have a certificate or you don't want to use HTTPS.
12391 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
12392 Where to find the private key for secure connections. Set it to @code{#f} if
12393 you don't have a key or you don't want to use HTTPS.
12395 @item @code{server-tokens?} (default: @code{#f})
12396 Whether the server should add its configuration to response.
12402 @subsubsection VPN Services
12403 @cindex VPN (virtual private network)
12404 @cindex virtual private network (VPN)
12406 The @code{(gnu services vpn)} module provides services related to
12407 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
12408 your machine to connect to a VPN, and a @emph{servire} service for your machine
12409 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
12411 @deffn {Scheme Procedure} openvpn-client-service @
12412 [#:config (openvpn-client-configuration)]
12414 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
12417 @deffn {Scheme Procedure} openvpn-server-service @
12418 [#:config (openvpn-server-configuration)]
12420 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
12422 Both can be run simultaneously.
12425 @c %automatically generated documentation
12427 Available @code{openvpn-client-configuration} fields are:
12429 @deftypevr @code{openvpn-client-configuration} parameter package openvpn
12430 The OpenVPN package.
12434 @deftypevr @code{openvpn-client-configuration} parameter string pid-file
12435 The OpenVPN pid file.
12437 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
12441 @deftypevr @code{openvpn-client-configuration} parameter proto proto
12442 The protocol (UDP or TCP) used to open a channel between clients and
12445 Defaults to @samp{udp}.
12449 @deftypevr @code{openvpn-client-configuration} parameter dev dev
12450 The device type used to represent the VPN connection.
12452 Defaults to @samp{tun}.
12456 @deftypevr @code{openvpn-client-configuration} parameter string ca
12457 The certificate authority to check connections against.
12459 Defaults to @samp{"/etc/openvpn/ca.crt"}.
12463 @deftypevr @code{openvpn-client-configuration} parameter string cert
12464 The certificate of the machine the daemon is running on. It should be
12465 signed by the authority given in @code{ca}.
12467 Defaults to @samp{"/etc/openvpn/client.crt"}.
12471 @deftypevr @code{openvpn-client-configuration} parameter string key
12472 The key of the machine the daemon is running on. It must be the key whose
12473 certificate is @code{cert}.
12475 Defaults to @samp{"/etc/openvpn/client.key"}.
12479 @deftypevr @code{openvpn-client-configuration} parameter boolean comp-lzo?
12480 Whether to use the lzo compression algorithm.
12482 Defaults to @samp{#t}.
12486 @deftypevr @code{openvpn-client-configuration} parameter boolean persist-key?
12487 Don't re-read key files across SIGUSR1 or --ping-restart.
12489 Defaults to @samp{#t}.
12493 @deftypevr @code{openvpn-client-configuration} parameter boolean persist-tun?
12494 Don't close and reopen TUN/TAP device or run up/down scripts across
12495 SIGUSR1 or --ping-restart restarts.
12497 Defaults to @samp{#t}.
12501 @deftypevr @code{openvpn-client-configuration} parameter number verbosity
12504 Defaults to @samp{3}.
12508 @deftypevr @code{openvpn-client-configuration} parameter tls-auth-client tls-auth
12509 Add an additional layer of HMAC authentication on top of the TLS control
12510 channel to protect against DoS attacks.
12512 Defaults to @samp{#f}.
12516 @deftypevr @code{openvpn-client-configuration} parameter key-usage verify-key-usage?
12517 Whether to check the server certificate has server usage extension.
12519 Defaults to @samp{#t}.
12523 @deftypevr @code{openvpn-client-configuration} parameter bind bind?
12524 Bind to a specific local port number.
12526 Defaults to @samp{#f}.
12530 @deftypevr @code{openvpn-client-configuration} parameter resolv-retry resolv-retry?
12531 Retry resolving server address.
12533 Defaults to @samp{#t}.
12537 @deftypevr @code{openvpn-client-configuration} parameter openvpn-remote-list remote
12538 A list of remote servers to connect to.
12540 Defaults to @samp{()}.
12542 Available @code{openvpn-remote-configuration} fields are:
12544 @deftypevr @code{openvpn-remote-configuration} parameter string name
12547 Defaults to @samp{"my-server"}.
12551 @deftypevr @code{openvpn-remote-configuration} parameter number port
12552 Port number the server listens to.
12554 Defaults to @samp{1194}.
12559 @c %end of automatic openvpn-client documentation
12561 @c %automatically generated documentation
12563 Available @code{openvpn-server-configuration} fields are:
12565 @deftypevr @code{openvpn-server-configuration} parameter package openvpn
12566 The OpenVPN package.
12570 @deftypevr @code{openvpn-server-configuration} parameter string pid-file
12571 The OpenVPN pid file.
12573 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
12577 @deftypevr @code{openvpn-server-configuration} parameter proto proto
12578 The protocol (UDP or TCP) used to open a channel between clients and
12581 Defaults to @samp{udp}.
12585 @deftypevr @code{openvpn-server-configuration} parameter dev dev
12586 The device type used to represent the VPN connection.
12588 Defaults to @samp{tun}.
12592 @deftypevr @code{openvpn-server-configuration} parameter string ca
12593 The certificate authority to check connections against.
12595 Defaults to @samp{"/etc/openvpn/ca.crt"}.
12599 @deftypevr @code{openvpn-server-configuration} parameter string cert
12600 The certificate of the machine the daemon is running on. It should be
12601 signed by the authority given in @code{ca}.
12603 Defaults to @samp{"/etc/openvpn/client.crt"}.
12607 @deftypevr @code{openvpn-server-configuration} parameter string key
12608 The key of the machine the daemon is running on. It must be the key whose
12609 certificate is @code{cert}.
12611 Defaults to @samp{"/etc/openvpn/client.key"}.
12615 @deftypevr @code{openvpn-server-configuration} parameter boolean comp-lzo?
12616 Whether to use the lzo compression algorithm.
12618 Defaults to @samp{#t}.
12622 @deftypevr @code{openvpn-server-configuration} parameter boolean persist-key?
12623 Don't re-read key files across SIGUSR1 or --ping-restart.
12625 Defaults to @samp{#t}.
12629 @deftypevr @code{openvpn-server-configuration} parameter boolean persist-tun?
12630 Don't close and reopen TUN/TAP device or run up/down scripts across
12631 SIGUSR1 or --ping-restart restarts.
12633 Defaults to @samp{#t}.
12637 @deftypevr @code{openvpn-server-configuration} parameter number verbosity
12640 Defaults to @samp{3}.
12644 @deftypevr @code{openvpn-server-configuration} parameter tls-auth-server tls-auth
12645 Add an additional layer of HMAC authentication on top of the TLS control
12646 channel to protect against DoS attacks.
12648 Defaults to @samp{#f}.
12652 @deftypevr @code{openvpn-server-configuration} parameter number port
12653 Specifies the port number on which the server listens.
12655 Defaults to @samp{1194}.
12659 @deftypevr @code{openvpn-server-configuration} parameter ip-mask server
12660 An ip and mask specifying the subnet inside the virtual network.
12662 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
12666 @deftypevr @code{openvpn-server-configuration} parameter cidr6 server-ipv6
12667 A CIDR notation specifying the IPv6 subnet inside the virtual network.
12669 Defaults to @samp{#f}.
12673 @deftypevr @code{openvpn-server-configuration} parameter string dh
12674 The Diffie-Hellman parameters file.
12676 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
12680 @deftypevr @code{openvpn-server-configuration} parameter string ifconfig-pool-persist
12681 The file that records client IPs.
12683 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
12687 @deftypevr @code{openvpn-server-configuration} parameter gateway redirect-gateway?
12688 When true, the server will act as a gateway for its clients.
12690 Defaults to @samp{#f}.
12694 @deftypevr @code{openvpn-server-configuration} parameter boolean client-to-client?
12695 When true, clients are alowed to talk to each other inside the VPN.
12697 Defaults to @samp{#f}.
12701 @deftypevr @code{openvpn-server-configuration} parameter keepalive keepalive
12702 Causes ping-like messages to be sent back and forth over the link so
12703 that each side knows when the other side has gone down. @code{keepalive}
12704 requires a pair. The first element is the period of the ping sending,
12705 and the second element is the timeout before considering the other side
12710 @deftypevr @code{openvpn-server-configuration} parameter number max-clients
12711 The maximum number of clients.
12713 Defaults to @samp{100}.
12717 @deftypevr @code{openvpn-server-configuration} parameter string status
12718 The status file. This file shows a small report on current connection.
12719 It is trunkated and rewritten every minute.
12721 Defaults to @samp{"/var/run/openvpn/status"}.
12725 @deftypevr @code{openvpn-server-configuration} parameter openvpn-ccd-list client-config-dir
12726 The list of configuration for some clients.
12728 Defaults to @samp{()}.
12730 Available @code{openvpn-ccd-configuration} fields are:
12732 @deftypevr @code{openvpn-ccd-configuration} parameter string name
12735 Defaults to @samp{"client"}.
12739 @deftypevr @code{openvpn-ccd-configuration} parameter ip-mask iroute
12742 Defaults to @samp{#f}.
12746 @deftypevr @code{openvpn-ccd-configuration} parameter ip-mask ifconfig-push
12749 Defaults to @samp{#f}.
12756 @c %end of automatic openvpn-server documentation
12759 @deftp {Data Type} nginx-upstream-configuration
12760 Data type representing the configuration of an nginx @code{upstream}
12761 block. This type has the following parameters:
12765 Name for this group of servers.
12767 @item @code{servers}
12768 Specify the addresses of the servers in the group. The address can be
12769 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
12770 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
12771 prefix @samp{unix:}. For addresses using an IP address or domain name,
12772 the default port is 80, and a different port can be specified
12778 @node Network File System
12779 @subsubsection Network File System
12782 The @code{(gnu services nfs)} module provides the following services,
12783 which are most commonly used in relation to mounting or exporting
12784 directory trees as @dfn{network file systems} (NFS).
12786 @subsubheading RPC Bind Service
12789 The RPC Bind service provides a facility to map program numbers into
12790 universal addresses.
12791 Many NFS related services use this facility. Hence it is automatically
12792 started when a dependent service starts.
12794 @defvr {Scheme Variable} rpcbind-service-type
12795 A service type for the RPC portmapper daemon.
12799 @deftp {Data Type} rpcbind-configuration
12800 Data type representing the configuration of the RPC Bind Service.
12801 This type has the following parameters:
12803 @item @code{rpcbind} (default: @code{rpcbind})
12804 The rpcbind package to use.
12806 @item @code{warm-start?} (default: @code{#t})
12807 If this parameter is @code{#t}, then the daemon will read a
12808 state file on startup thus reloading state information saved by a previous
12814 @subsubheading Pipefs Pseudo File System
12818 The pipefs file system is used to transfer NFS related data
12819 between the kernel and user space programs.
12821 @defvr {Scheme Variable} pipefs-service-type
12822 A service type for the pipefs pseudo file system.
12825 @deftp {Data Type} pipefs-configuration
12826 Data type representing the configuration of the pipefs pseudo file system service.
12827 This type has the following parameters:
12829 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
12830 The directory to which the file system is to be attached.
12835 @subsubheading GSS Daemon Service
12838 @cindex global security system
12840 The @dfn{global security system} (GSS) daemon provides strong security for RPC
12842 Before exchanging RPC requests an RPC client must establish a security
12843 context. Typically this is done using the Kerberos command @command{kinit}
12844 or automatically at login time using PAM services (@pxref{Kerberos Services}).
12846 @defvr {Scheme Variable} gss-service-type
12847 A service type for the Global Security System (GSS) daemon.
12850 @deftp {Data Type} gss-configuration
12851 Data type representing the configuration of the GSS daemon service.
12852 This type has the following parameters:
12854 @item @code{nfs-utils} (default: @code{nfs-utils})
12855 The package in which the @command{rpc.gssd} command is to be found.
12857 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
12858 The directory where the pipefs file system is mounted.
12864 @subsubheading IDMAP Daemon Service
12866 @cindex name mapper
12868 The idmap daemon service provides mapping between user IDs and user names.
12869 Typically it is required in order to access file systems mounted via NFSv4.
12871 @defvr {Scheme Variable} idmap-service-type
12872 A service type for the Identity Mapper (IDMAP) daemon.
12875 @deftp {Data Type} idmap-configuration
12876 Data type representing the configuration of the IDMAP daemon service.
12877 This type has the following parameters:
12879 @item @code{nfs-utils} (default: @code{nfs-utils})
12880 The package in which the @command{rpc.idmapd} command is to be found.
12882 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
12883 The directory where the pipefs file system is mounted.
12885 @item @code{domain} (default: @code{#f})
12886 The local NFSv4 domain name.
12887 This must be a string or @code{#f}.
12888 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
12893 @node Continuous Integration
12894 @subsubsection Continuous Integration
12896 @cindex continuous integration
12897 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
12898 integration tool for Guix. It can be used both for development and for
12899 providing substitutes to others (@pxref{Substitutes}).
12901 The @code{(gnu services cuirass)} module provides the following service.
12903 @defvr {Scheme Procedure} cuirass-service-type
12904 The type of the Cuirass service. Its value must be a
12905 @code{cuirass-configuration} object, as described below.
12908 To add build jobs, you have to set the @code{specifications} field of
12909 the configuration. Here is an example of a service defining a build job
12910 based on a specification that can be found in Cuirass source tree. This
12911 service polls the Guix repository and builds a subset of the Guix
12912 packages, as prescribed in the @file{gnu-system.scm} example spec:
12915 (let ((spec #~((#:name . "guix")
12916 (#:url . "git://git.savannah.gnu.org/guix.git")
12917 (#:load-path . ".")
12919 ;; Here we must provide an absolute file name.
12920 ;; We take jobs from one of the examples provided
12922 (#:file . #$(file-append
12924 "/tests/gnu-system.scm"))
12926 (#:proc . hydra-jobs)
12927 (#:arguments (subset . "hello"))
12928 (#:branch . "master"))))
12929 (service cuirass-service-type
12930 (cuirass-configuration
12931 (specifications #~(list #$spec)))))
12934 While information related to build jobs is located directly in the
12935 specifications, global settings for the @command{cuirass} process are
12936 accessible in other @code{cuirass-configuration} fields.
12938 @deftp {Data Type} cuirass-configuration
12939 Data type representing the configuration of Cuirass.
12942 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
12943 Location of the log file.
12945 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
12946 Location of the repository cache.
12948 @item @code{user} (default: @code{"cuirass"})
12949 Owner of the @code{cuirass} process.
12951 @item @code{group} (default: @code{"cuirass"})
12952 Owner's group of the @code{cuirass} process.
12954 @item @code{interval} (default: @code{60})
12955 Number of seconds between the poll of the repositories followed by the
12958 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
12959 Location of sqlite database which contains the build results and previously
12960 added specifications.
12962 @item @code{specifications} (default: @code{#~'()})
12963 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
12964 where a specification is an association list
12965 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
12966 keys are keywords (@code{#:keyword-example}) as shown in the example
12969 @item @code{use-substitutes?} (default: @code{#f})
12970 This allows using substitutes to avoid building every dependencies of a job
12973 @item @code{one-shot?} (default: @code{#f})
12974 Only evaluate specifications and build derivations once.
12976 @item @code{cuirass} (default: @code{cuirass})
12977 The Cuirass package to use.
12981 @node Miscellaneous Services
12982 @subsubsection Miscellaneous Services
12986 @subsubheading Lirc Service
12988 The @code{(gnu services lirc)} module provides the following service.
12990 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
12991 [#:device #f] [#:driver #f] [#:config-file #f] @
12992 [#:extra-options '()]
12993 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
12994 decodes infrared signals from remote controls.
12996 Optionally, @var{device}, @var{driver} and @var{config-file}
12997 (configuration file name) may be specified. See @command{lircd} manual
13000 Finally, @var{extra-options} is a list of additional command-line options
13001 passed to @command{lircd}.
13005 @subsubheading Spice Service
13007 The @code{(gnu services spice)} module provides the following service.
13009 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
13010 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
13011 that enables sharing the clipboard with a vm and setting the guest display
13012 resolution when the graphical console window resizes.
13015 @subsubsection Dictionary Services
13017 The @code{(gnu services dict)} module provides the following service:
13019 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
13020 Return a service that runs the @command{dicod} daemon, an implementation
13021 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
13023 The optional @var{config} argument specifies the configuration for
13024 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
13025 default it serves the GNU Collaborative International Dictonary of English.
13027 You can add @command{open localhost} to your @file{~/.dico} file to make
13028 @code{localhost} the default server for @command{dico} client
13029 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
13032 @deftp {Data Type} dicod-configuration
13033 Data type representing the configuration of dicod.
13036 @item @code{dico} (default: @var{dico})
13037 Package object of the GNU Dico dictionary server.
13039 @item @code{interfaces} (default: @var{'("localhost")})
13040 This is the list of IP addresses and ports and possibly socket file
13041 names to listen to (@pxref{Server Settings, @code{listen} directive,,
13042 dico, GNU Dico Manual}).
13044 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
13045 List of @code{<dicod-database>} objects denoting dictionaries to be served.
13049 @deftp {Data Type} dicod-database
13050 Data type representing a dictionary database.
13054 Name of the database, will be used in DICT commands.
13056 @item @code{module}
13057 Name of the dicod module used by this database
13058 (@pxref{Modules,,, dico, GNU Dico Manual}).
13060 @item @code{options}
13061 List of strings or gexps representing the arguments for the module handler
13062 (@pxref{Handlers,,, dico, GNU Dico Manual}).
13066 @defvr {Scheme Variable} %dicod-database:gcide
13067 A @code{<dicod-database>} object serving the GNU Collaborative International
13068 Dictonary of English using the @code{gcide} package.
13071 @subsubsection Version Control
13073 The @code{(gnu services version-control)} module provides the following services:
13075 @subsubheading Git daemon service
13077 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
13079 Return a service that runs @command{git daemon}, a simple TCP server to
13080 expose repositiories over the Git protocol for annoymous access.
13082 The optional @var{config} argument should be a
13083 @code{<git-daemon-configuration>} object, by default it allows read-only
13084 access to exported@footnote{By creating the magic file
13085 "git-daemon-export-ok" in the repository directory.} repositories under
13090 @deftp {Data Type} git-daemon-configuration
13091 Data type representing the configuration for @code{git-daemon-service}.
13094 @item @code{package} (default: @var{git})
13095 Package object of the Git distributed version control system.
13097 @item @code{export-all?} (default: @var{#f})
13098 Whether to allow access for all Git repositories, even if they do not
13099 have the @file{git-daemon-export-ok} file.
13101 @item @code{base-path} (default: @file{/srv/git})
13102 Whether to remap all the path requests as relative to the given path.
13103 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
13104 then if you later try to pull @code{git://example.com/hello.git}, git
13105 daemon will interpret the path as @code{/srv/git/hello.git}.
13107 @item @code{user-path} (default: @var{#f})
13108 Whether to allow @code{~user} notation to be used in requests. When
13109 specified with empty string, requests to @code{git://host/~alice/foo} is
13110 taken as a request to access @code{foo} repository in the home directory
13111 of user @code{alice}. If @var{(user-path "path")} is specified, the
13112 same request is taken as a request to access @code{path/foo} repository
13113 in the home directory of user @code{alice}.
13115 @item @code{listen} (default: @var{'()})
13116 Whether to listen on specific IP addresses or hostnames, defaults to
13119 @item @code{port} (default: @var{#f})
13120 Whether to listen on an alternative port, which defaults to 9418.
13122 @item @code{whitelist} (default: @var{'()})
13123 If not empty, only allow access to this list of directories.
13125 @item @code{extra-options} (default: @var{'()})
13126 Extra options will be passed to @code{git daemon}, please run
13127 @command{man git-daemon} for more information.
13132 @node Setuid Programs
13133 @subsection Setuid Programs
13135 @cindex setuid programs
13136 Some programs need to run with ``root'' privileges, even when they are
13137 launched by unprivileged users. A notorious example is the
13138 @command{passwd} program, which users can run to change their
13139 password, and which needs to access the @file{/etc/passwd} and
13140 @file{/etc/shadow} files---something normally restricted to root, for
13141 obvious security reasons. To address that, these executables are
13142 @dfn{setuid-root}, meaning that they always run with root privileges
13143 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
13144 for more info about the setuid mechanism.)
13146 The store itself @emph{cannot} contain setuid programs: that would be a
13147 security issue since any user on the system can write derivations that
13148 populate the store (@pxref{The Store}). Thus, a different mechanism is
13149 used: instead of changing the setuid bit directly on files that are in
13150 the store, we let the system administrator @emph{declare} which programs
13151 should be setuid root.
13153 The @code{setuid-programs} field of an @code{operating-system}
13154 declaration contains a list of G-expressions denoting the names of
13155 programs to be setuid-root (@pxref{Using the Configuration System}).
13156 For instance, the @command{passwd} program, which is part of the Shadow
13157 package, can be designated by this G-expression (@pxref{G-Expressions}):
13160 #~(string-append #$shadow "/bin/passwd")
13163 A default set of setuid programs is defined by the
13164 @code{%setuid-programs} variable of the @code{(gnu system)} module.
13166 @defvr {Scheme Variable} %setuid-programs
13167 A list of G-expressions denoting common programs that are setuid-root.
13169 The list includes commands such as @command{passwd}, @command{ping},
13170 @command{su}, and @command{sudo}.
13173 Under the hood, the actual setuid programs are created in the
13174 @file{/run/setuid-programs} directory at system activation time. The
13175 files in this directory refer to the ``real'' binaries, which are in the
13178 @node X.509 Certificates
13179 @subsection X.509 Certificates
13181 @cindex HTTPS, certificates
13182 @cindex X.509 certificates
13184 Web servers available over HTTPS (that is, HTTP over the transport-layer
13185 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
13186 that the client can then use to @emph{authenticate} the server. To do
13187 that, clients verify that the server's certificate is signed by a
13188 so-called @dfn{certificate authority} (CA). But to verify the CA's
13189 signature, clients must have first acquired the CA's certificate.
13191 Web browsers such as GNU@tie{}IceCat include their own set of CA
13192 certificates, such that they are able to verify CA signatures
13195 However, most other programs that can talk HTTPS---@command{wget},
13196 @command{git}, @command{w3m}, etc.---need to be told where CA
13197 certificates can be found.
13199 @cindex @code{nss-certs}
13200 In GuixSD, this is done by adding a package that provides certificates
13201 to the @code{packages} field of the @code{operating-system} declaration
13202 (@pxref{operating-system Reference}). GuixSD includes one such package,
13203 @code{nss-certs}, which is a set of CA certificates provided as part of
13204 Mozilla's Network Security Services.
13206 Note that it is @emph{not} part of @var{%base-packages}, so you need to
13207 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
13208 most applications and libraries look for certificates by default, points
13209 to the certificates installed globally.
13211 Unprivileged users, including users of Guix on a foreign distro,
13212 can also install their own certificate package in
13213 their profile. A number of environment variables need to be defined so
13214 that applications and libraries know where to find them. Namely, the
13215 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
13216 variables. Some applications add their own environment variables; for
13217 instance, the Git version control system honors the certificate bundle
13218 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
13219 would typically run something like:
13222 $ guix package -i nss-certs
13223 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
13224 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
13225 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
13228 @node Name Service Switch
13229 @subsection Name Service Switch
13231 @cindex name service switch
13233 The @code{(gnu system nss)} module provides bindings to the
13234 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
13235 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
13236 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
13237 extended with new ``name'' lookup methods for system databases, which
13238 includes host names, service names, user accounts, and more (@pxref{Name
13239 Service Switch, System Databases and Name Service Switch,, libc, The GNU
13240 C Library Reference Manual}).
13242 The NSS configuration specifies, for each system database, which lookup
13243 method is to be used, and how the various methods are chained
13244 together---for instance, under which circumstances NSS should try the
13245 next method in the list. The NSS configuration is given in the
13246 @code{name-service-switch} field of @code{operating-system} declarations
13247 (@pxref{operating-system Reference, @code{name-service-switch}}).
13250 @cindex .local, host name lookup
13251 As an example, the declaration below configures the NSS to use the
13252 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
13253 back-end}, which supports host name lookups over multicast DNS (mDNS)
13254 for host names ending in @code{.local}:
13257 (name-service-switch
13258 (hosts (list %files ;first, check /etc/hosts
13260 ;; If the above did not succeed, try
13261 ;; with 'mdns_minimal'.
13263 (name "mdns_minimal")
13265 ;; 'mdns_minimal' is authoritative for
13266 ;; '.local'. When it returns "not found",
13267 ;; no need to try the next methods.
13268 (reaction (lookup-specification
13269 (not-found => return))))
13271 ;; Then fall back to DNS.
13275 ;; Finally, try with the "full" 'mdns'.
13280 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
13281 contains this configuration, so you will not have to type it if all you
13282 want is to have @code{.local} host lookup working.
13284 Note that, in this case, in addition to setting the
13285 @code{name-service-switch} of the @code{operating-system} declaration,
13286 you also need to use @code{avahi-service} (@pxref{Networking Services,
13287 @code{avahi-service}}), or @var{%desktop-services}, which includes it
13288 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
13289 to the name service cache daemon (@pxref{Base Services,
13290 @code{nscd-service}}).
13292 For convenience, the following variables provide typical NSS
13295 @defvr {Scheme Variable} %default-nss
13296 This is the default name service switch configuration, a
13297 @code{name-service-switch} object.
13300 @defvr {Scheme Variable} %mdns-host-lookup-nss
13301 This is the name service switch configuration with support for host name
13302 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
13305 The reference for name service switch configuration is given below. It
13306 is a direct mapping of the configuration file format of the C library , so
13307 please refer to the C library manual for more information (@pxref{NSS
13308 Configuration File,,, libc, The GNU C Library Reference Manual}).
13309 Compared to the configuration file format of libc NSS, it has the advantage
13310 not only of adding this warm parenthetic feel that we like, but also
13311 static checks: you will know about syntax errors and typos as soon as you
13312 run @command{guix system}.
13314 @deftp {Data Type} name-service-switch
13316 This is the data type representation the configuration of libc's name
13317 service switch (NSS). Each field below represents one of the supported
13334 The system databases handled by the NSS. Each of these fields must be a
13335 list of @code{<name-service>} objects (see below).
13339 @deftp {Data Type} name-service
13341 This is the data type representing an actual name service and the
13342 associated lookup action.
13346 A string denoting the name service (@pxref{Services in the NSS
13347 configuration,,, libc, The GNU C Library Reference Manual}).
13349 Note that name services listed here must be visible to nscd. This is
13350 achieved by passing the @code{#:name-services} argument to
13351 @code{nscd-service} the list of packages providing the needed name
13352 services (@pxref{Base Services, @code{nscd-service}}).
13355 An action specified using the @code{lookup-specification} macro
13356 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
13357 Reference Manual}). For example:
13360 (lookup-specification (unavailable => continue)
13361 (success => return))
13366 @node Initial RAM Disk
13367 @subsection Initial RAM Disk
13370 @cindex initial RAM disk
13371 For bootstrapping purposes, the Linux-Libre kernel is passed an
13372 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
13373 root file system as well as an initialization script. The latter is
13374 responsible for mounting the real root file system, and for loading any
13375 kernel modules that may be needed to achieve that.
13377 The @code{initrd} field of an @code{operating-system} declaration allows
13378 you to specify which initrd you would like to use. The @code{(gnu
13379 system linux-initrd)} module provides two ways to build an initrd: the
13380 high-level @code{base-initrd} procedure, and the low-level
13381 @code{expression->initrd} procedure.
13383 The @code{base-initrd} procedure is intended to cover most common uses.
13384 For example, if you want to add a bunch of kernel modules to be loaded
13385 at boot time, you can define the @code{initrd} field of the operating
13386 system declaration like this:
13389 (initrd (lambda (file-systems . rest)
13390 ;; Create a standard initrd that has modules "foo.ko"
13391 ;; and "bar.ko", as well as their dependencies, in
13392 ;; addition to the modules available by default.
13393 (apply base-initrd file-systems
13394 #:extra-modules '("foo" "bar")
13398 The @code{base-initrd} procedure also handles common use cases that
13399 involves using the system as a QEMU guest, or as a ``live'' system with
13400 volatile root file system.
13402 The initial RAM disk produced by @code{base-initrd} honors several
13403 options passed on the Linux kernel command line (that is, arguments
13404 passed @i{via} the @code{linux} command of GRUB, or the
13405 @code{-append} option of QEMU), notably:
13408 @item --load=@var{boot}
13409 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
13410 program, once it has mounted the root file system.
13412 GuixSD uses this option to yield control to a boot program that runs the
13413 service activation programs and then spawns the GNU@tie{}Shepherd, the
13414 initialization system.
13416 @item --root=@var{root}
13417 Mount @var{root} as the root file system. @var{root} can be a
13418 device name like @code{/dev/sda1}, a partition label, or a partition
13421 @item --system=@var{system}
13422 Have @file{/run/booted-system} and @file{/run/current-system} point to
13425 @item modprobe.blacklist=@var{modules}@dots{}
13426 @cindex module, black-listing
13427 @cindex black list, of kernel modules
13428 Instruct the initial RAM disk as well as the @command{modprobe} command
13429 (from the kmod package) to refuse to load @var{modules}. @var{modules}
13430 must be a comma-separated list of module names---e.g.,
13431 @code{usbkbd,9pnet}.
13434 Start a read-eval-print loop (REPL) from the initial RAM disk before it
13435 tries to load kernel modules and to mount the root file system. Our
13436 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
13437 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
13438 Manual}, for more information on Guile's REPL.
13442 Now that you know all the features that initial RAM disks produced by
13443 @code{base-initrd} provide, here is how to use it and customize it
13447 @cindex initial RAM disk
13448 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
13449 [#:qemu-networking? #f] [#:virtio? #t] [#:volatile-root? #f] @
13450 [#:extra-modules '()] [#:mapped-devices '()]
13451 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
13452 a list of file systems to be mounted by the initrd, possibly in addition to
13453 the root file system specified on the kernel command line via @code{--root}.
13454 @var{mapped-devices} is a list of device mappings to realize before
13455 @var{file-systems} are mounted (@pxref{Mapped Devices}).
13457 When @var{qemu-networking?} is true, set up networking with the standard QEMU
13458 parameters. When @var{virtio?} is true, load additional modules so that the
13459 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
13461 When @var{volatile-root?} is true, the root file system is writable but any changes
13464 The initrd is automatically populated with all the kernel modules necessary
13465 for @var{file-systems} and for the given options. However, additional kernel
13466 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
13467 loaded at boot time in the order in which they appear.
13470 Needless to say, the initrds we produce and use embed a
13471 statically-linked Guile, and the initialization program is a Guile
13472 program. That gives a lot of flexibility. The
13473 @code{expression->initrd} procedure builds such an initrd, given the
13474 program to run in that initrd.
13476 @deffn {Monadic Procedure} expression->initrd @var{exp} @
13477 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
13478 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
13479 containing @var{guile} and that evaluates @var{exp}, a G-expression,
13480 upon booting. All the derivations referenced by @var{exp} are
13481 automatically copied to the initrd.
13484 @node GRUB Configuration
13485 @subsection GRUB Configuration
13488 @cindex boot loader
13490 The operating system uses GNU@tie{}GRUB as its boot loader
13491 (@pxref{Overview, overview of GRUB,, grub, GNU GRUB Manual}). It is
13492 configured using a @code{grub-configuration} declaration. This data type
13493 is exported by the @code{(gnu system grub)} module and described below.
13495 @deftp {Data Type} grub-configuration
13496 The type of a GRUB configuration declaration.
13500 @item @code{device}
13501 This is a string denoting the boot device. It must be a device name
13502 understood by the @command{grub-install} command, such as
13503 @code{/dev/sda} or @code{(hd0)} (@pxref{Invoking grub-install,,, grub,
13506 @item @code{menu-entries} (default: @code{()})
13507 A possibly empty list of @code{menu-entry} objects (see below), denoting
13508 entries to appear in the GRUB boot menu, in addition to the current
13509 system entry and the entry pointing to previous system generations.
13511 @item @code{default-entry} (default: @code{0})
13512 The index of the default boot menu entry. Index 0 is for the entry of the
13515 @item @code{timeout} (default: @code{5})
13516 The number of seconds to wait for keyboard input before booting. Set to
13517 0 to boot immediately, and to -1 to wait indefinitely.
13519 @item @code{theme} (default: @var{%default-theme})
13520 The @code{grub-theme} object describing the theme to use.
13522 @item @code{grub} (default: @code{grub})
13523 The GRUB package to use.
13530 Should you want to list additional boot menu entries @i{via} the
13531 @code{menu-entries} field above, you will need to create them with the
13532 @code{menu-entry} form. For example, imagine you want to be able to
13533 boot another distro (hard to imagine!), you can define a menu entry
13538 (label "The Other Distro")
13539 (linux "/boot/old/vmlinux-2.6.32")
13540 (linux-arguments '("root=/dev/sda2"))
13541 (initrd "/boot/old/initrd"))
13546 @deftp {Data Type} menu-entry
13547 The type of an entry in the GRUB boot menu.
13552 The label to show in the menu---e.g., @code{"GNU"}.
13555 The Linux kernel image to boot, for example:
13558 (file-append linux-libre "/bzImage")
13561 It is also possible to specify a device explicitly in the file path
13562 using GRUB's device naming convention (@pxref{Naming convention,,, grub,
13563 GNU GRUB manual}), for example:
13566 "(hd0,msdos1)/boot/vmlinuz"
13569 If the device is specified explicitly as above, then the @code{device}
13570 field is ignored entirely.
13572 @item @code{linux-arguments} (default: @code{()})
13573 The list of extra Linux kernel command-line arguments---e.g.,
13574 @code{("console=ttyS0")}.
13576 @item @code{initrd}
13577 A G-Expression or string denoting the file name of the initial RAM disk
13578 to use (@pxref{G-Expressions}).
13580 @item @code{device} (default: @code{#f})
13581 The device where the kernel and initrd are to be found---i.e., the GRUB
13582 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
13584 This may be a file system label (a string), a file system UUID (a
13585 bytevector, @pxref{File Systems}), or @code{#f}, in which case GRUB will
13586 search the device containing the file specified by the @code{linux}
13587 field (@pxref{search,,, grub, GNU GRUB manual}). It must @emph{not} be
13588 an OS device name such as @file{/dev/sda1}.
13590 @item @code{device-mount-point} (default: @code{"/"})
13591 The mount point of the above device on the system. You probably do not
13592 need to change the default value. GuixSD uses it to strip the prefix of
13593 store file names for systems where @file{/gnu} or @file{/gnu/store} is
13594 on a separate partition.
13599 @c FIXME: Write documentation once it's stable.
13600 Themes are created using the @code{grub-theme} form, which is not
13603 @defvr {Scheme Variable} %default-theme
13604 This is the default GRUB theme used by the operating system, with a
13605 fancy background image displaying the GNU and Guix logos.
13609 @node Invoking guix system
13610 @subsection Invoking @code{guix system}
13612 Once you have written an operating system declaration as seen in the
13613 previous section, it can be @dfn{instantiated} using the @command{guix
13614 system} command. The synopsis is:
13617 guix system @var{options}@dots{} @var{action} @var{file}
13620 @var{file} must be the name of a file containing an
13621 @code{operating-system} declaration. @var{action} specifies how the
13622 operating system is instantiated. Currently the following values are
13627 Build the operating system described in @var{file}, activate it, and
13628 switch to it@footnote{This action (and the related actions
13629 @code{switch-generation} and @code{roll-back}) are usable only on
13630 systems already running GuixSD.}.
13632 This effects all the configuration specified in @var{file}: user
13633 accounts, system services, global package list, setuid programs, etc.
13634 The command starts system services specified in @var{file} that are not
13635 currently running; if a service is currently running, it does not
13636 attempt to upgrade it since this would not be possible without stopping it
13639 This command creates a new generation whose number is one greater than
13640 the current generation (as reported by @command{guix system
13641 list-generations}). If that generation already exists, it will be
13642 overwritten. This behavior mirrors that of @command{guix package}
13643 (@pxref{Invoking guix package}).
13645 It also adds a GRUB menu entry for the new OS configuration, and moves
13646 entries for older configurations to a submenu---unless
13647 @option{--no-grub} is passed.
13650 @c The paragraph below refers to the problem discussed at
13651 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
13652 It is highly recommended to run @command{guix pull} once before you run
13653 @command{guix system reconfigure} for the first time (@pxref{Invoking
13654 guix pull}). Failing to do that you would see an older version of Guix
13655 once @command{reconfigure} has completed.
13658 @item switch-generation
13659 @cindex generations
13660 Switch to an existing system generation. This action atomically
13661 switches the system profile to the specified system generation. It also
13662 rearranges the system's existing GRUB menu entries. It makes the menu
13663 entry for the specified system generation the default, and it moves the
13664 entries for the other generations to a submenu. The next time the
13665 system boots, it will use the specified system generation.
13667 The target generation can be specified explicitly by its generation
13668 number. For example, the following invocation would switch to system
13672 guix system switch-generation 7
13675 The target generation can also be specified relative to the current
13676 generation with the form @code{+N} or @code{-N}, where @code{+3} means
13677 ``3 generations ahead of the current generation,'' and @code{-1} means
13678 ``1 generation prior to the current generation.'' When specifying a
13679 negative value such as @code{-1}, you must precede it with @code{--} to
13680 prevent it from being parsed as an option. For example:
13683 guix system switch-generation -- -1
13686 Currently, the effect of invoking this action is @emph{only} to switch
13687 the system profile to an existing generation and rearrange the GRUB menu
13688 entries. To actually start using the target system generation, you must
13689 reboot after running this action. In the future, it will be updated to
13690 do the same things as @command{reconfigure}, like activating and
13691 deactivating services.
13693 This action will fail if the specified generation does not exist.
13696 @cindex rolling back
13697 Switch to the preceding system generation. The next time the system
13698 boots, it will use the preceding system generation. This is the inverse
13699 of @command{reconfigure}, and it is exactly the same as invoking
13700 @command{switch-generation} with an argument of @code{-1}.
13702 Currently, as with @command{switch-generation}, you must reboot after
13703 running this action to actually start using the preceding system
13707 Build the derivation of the operating system, which includes all the
13708 configuration files and programs needed to boot and run the system.
13709 This action does not actually install anything.
13712 Populate the given directory with all the files necessary to run the
13713 operating system specified in @var{file}. This is useful for first-time
13714 installations of GuixSD. For instance:
13717 guix system init my-os-config.scm /mnt
13720 copies to @file{/mnt} all the store items required by the configuration
13721 specified in @file{my-os-config.scm}. This includes configuration
13722 files, packages, and so on. It also creates other essential files
13723 needed for the system to operate correctly---e.g., the @file{/etc},
13724 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
13726 This command also installs GRUB on the device specified in
13727 @file{my-os-config}, unless the @option{--no-grub} option was passed.
13730 @cindex virtual machine
13732 @anchor{guix system vm}
13733 Build a virtual machine that contains the operating system declared in
13734 @var{file}, and return a script to run that virtual machine (VM).
13735 Arguments given to the script are passed to QEMU.
13737 The VM shares its store with the host system.
13739 Additional file systems can be shared between the host and the VM using
13740 the @code{--share} and @code{--expose} command-line options: the former
13741 specifies a directory to be shared with write access, while the latter
13742 provides read-only access to the shared directory.
13744 The example below creates a VM in which the user's home directory is
13745 accessible read-only, and where the @file{/exchange} directory is a
13746 read-write mapping of @file{$HOME/tmp} on the host:
13749 guix system vm my-config.scm \
13750 --expose=$HOME --share=$HOME/tmp=/exchange
13753 On GNU/Linux, the default is to boot directly to the kernel; this has
13754 the advantage of requiring only a very tiny root disk image since the
13755 store of the host can then be mounted.
13757 The @code{--full-boot} option forces a complete boot sequence, starting
13758 with the bootloader. This requires more disk space since a root image
13759 containing at least the kernel, initrd, and bootloader data files must
13760 be created. The @code{--image-size} option can be used to specify the
13765 Return a virtual machine or disk image of the operating system declared
13766 in @var{file} that stands alone. Use the @option{--image-size} option
13767 to specify the size of the image.
13769 When using @code{vm-image}, the returned image is in qcow2 format, which
13770 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
13771 for more information on how to run the image in a virtual machine.
13773 When using @code{disk-image}, a raw disk image is produced; it can be
13774 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
13775 the device corresponding to a USB stick, one can copy the image to it
13776 using the following command:
13779 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
13783 Return a script to run the operating system declared in @var{file}
13784 within a container. Containers are a set of lightweight isolation
13785 mechanisms provided by the kernel Linux-libre. Containers are
13786 substantially less resource-demanding than full virtual machines since
13787 the kernel, shared objects, and other resources can be shared with the
13788 host system; this also means they provide thinner isolation.
13790 Currently, the script must be run as root in order to support more than
13791 a single user and group. The container shares its store with the host
13794 As with the @code{vm} action (@pxref{guix system vm}), additional file
13795 systems to be shared between the host and container can be specified
13796 using the @option{--share} and @option{--expose} options:
13799 guix system container my-config.scm \
13800 --expose=$HOME --share=$HOME/tmp=/exchange
13804 This option requires Linux-libre 3.19 or newer.
13809 @var{options} can contain any of the common build options (@pxref{Common
13810 Build Options}). In addition, @var{options} can contain one of the
13814 @item --system=@var{system}
13815 @itemx -s @var{system}
13816 Attempt to build for @var{system} instead of the host system type.
13817 This works as per @command{guix build} (@pxref{Invoking guix build}).
13821 Return the derivation file name of the given operating system without
13824 @item --image-size=@var{size}
13825 For the @code{vm-image} and @code{disk-image} actions, create an image
13826 of the given @var{size}. @var{size} may be a number of bytes, or it may
13827 include a unit as a suffix (@pxref{Block size, size specifications,,
13828 coreutils, GNU Coreutils}).
13830 @item --on-error=@var{strategy}
13831 Apply @var{strategy} when an error occurs when reading @var{file}.
13832 @var{strategy} may be one of the following:
13835 @item nothing-special
13836 Report the error concisely and exit. This is the default strategy.
13839 Likewise, but also display a backtrace.
13842 Report the error and enter Guile's debugger. From there, you can run
13843 commands such as @code{,bt} to get a backtrace, @code{,locals} to
13844 display local variable values, and more generally inspect the state of the
13845 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
13846 a list of available debugging commands.
13851 All the actions above, except @code{build} and @code{init},
13852 can use KVM support in the Linux-libre kernel. Specifically, if the
13853 machine has hardware virtualization support, the corresponding
13854 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
13855 must exist and be readable and writable by the user and by the
13856 build users of the daemon (@pxref{Build Environment Setup}).
13859 Once you have built, configured, re-configured, and re-re-configured
13860 your GuixSD installation, you may find it useful to list the operating
13861 system generations available on disk---and that you can choose from the
13866 @item list-generations
13867 List a summary of each generation of the operating system available on
13868 disk, in a human-readable way. This is similar to the
13869 @option{--list-generations} option of @command{guix package}
13870 (@pxref{Invoking guix package}).
13872 Optionally, one can specify a pattern, with the same syntax that is used
13873 in @command{guix package --list-generations}, to restrict the list of
13874 generations displayed. For instance, the following command displays
13875 generations that are up to 10 days old:
13878 $ guix system list-generations 10d
13883 The @command{guix system} command has even more to offer! The following
13884 sub-commands allow you to visualize how your system services relate to
13887 @anchor{system-extension-graph}
13890 @item extension-graph
13891 Emit in Dot/Graphviz format to standard output the @dfn{service
13892 extension graph} of the operating system defined in @var{file}
13893 (@pxref{Service Composition}, for more information on service
13899 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
13902 produces a PDF file showing the extension relations among services.
13904 @anchor{system-shepherd-graph}
13905 @item shepherd-graph
13906 Emit in Dot/Graphviz format to standard output the @dfn{dependency
13907 graph} of shepherd services of the operating system defined in
13908 @var{file}. @xref{Shepherd Services}, for more information and for an
13913 @node Running GuixSD in a VM
13914 @subsection Running GuixSD in a Virtual Machine
13916 @cindex virtual machine
13917 One way to run GuixSD in a virtual machine (VM) is to build a GuixSD
13918 virtual machine image using @command{guix system vm-image}
13919 (@pxref{Invoking guix system}). The returned image is in qcow2 format,
13920 which the @uref{http://qemu.org/, QEMU emulator} can efficiently use.
13923 To run the image in QEMU, copy it out of the store (@pxref{The Store})
13924 and give yourself permission to write to the copy. When invoking QEMU,
13925 you must choose a system emulator that is suitable for your hardware
13926 platform. Here is a minimal QEMU invocation that will boot the result
13927 of @command{guix system vm-image} on x86_64 hardware:
13930 $ qemu-system-x86_64 \
13931 -net user -net nic,model=virtio \
13932 -enable-kvm -m 256 /tmp/qemu-image
13935 Here is what each of these options means:
13938 @item qemu-system-x86_64
13939 This specifies the hardware platform to emulate. This should match the
13943 Enable the unprivileged user-mode network stack. The guest OS can
13944 access the host but not vice versa. This is the simplest way to get the
13947 @item -net nic,model=virtio
13948 You must create a network interface of a given model. If you do not
13949 create a NIC, the boot will fail. Assuming your hardware platform is
13950 x86_64, you can get a list of available NIC models by running
13951 @command{qemu-system-x86_64 -net nic,model=help}.
13954 If your system has hardware virtualization extensions, enabling the
13955 virtual machine support (KVM) of the Linux kernel will make things run
13959 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
13960 which may be insufficient for some operations.
13962 @item /tmp/qemu-image
13963 The file name of the qcow2 image.
13966 The default @command{run-vm.sh} script that is returned by an invokation of
13967 @command{guix system vm} does not add a @command{-net user} flag by default.
13968 To get network access from within the vm add the @code{(dhcp-client-service)}
13969 to your system definition and start the VM using
13970 @command{`guix system vm config.scm` -net user}. An important caveat of using
13971 @command{-net user} for networking is that @command{ping} will not work, because
13972 it uses the ICMP protocol. You'll have to use a different command to check for
13973 network connectivity, like for example @command{curl}.
13975 @subsubsection Connecting Through SSH
13979 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
13980 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
13981 boot unsupervised. It requires you to type some characters to initialize the
13982 randomness generator. In addition you need to forward the SSH port, 22 by
13983 default, to the host. You can do this with
13986 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
13989 To connect to the VM you can run
13992 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
13995 The @command{-p} tells @command{ssh} the port you want to connect to.
13996 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
13997 every time you modify your @command{config.scm} file and the
13998 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
13999 connection to an unknown host every time you connect.
14001 @subsubsection Using @command{virt-viewer} with Spice
14003 As an alternative to the default @command{qemu} graphical client you can
14004 use the @command{remote-viewer} from the @command{virt-viewer} package. To
14005 connect pass the @command{-spice port=5930,disable-ticketing} flag to
14006 @command{qemu}. See previous section for further information on how to do this.
14008 Spice also allows you to do some nice stuff like share your clipboard with your
14009 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
14012 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
14013 -chardev spicevmc,name=vdagent,id=vdagent
14014 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
14015 name=com.redhat.spice.0
14018 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
14020 @node Defining Services
14021 @subsection Defining Services
14023 The previous sections show the available services and how one can combine
14024 them in an @code{operating-system} declaration. But how do we define
14025 them in the first place? And what is a service anyway?
14028 * Service Composition:: The model for composing services.
14029 * Service Types and Services:: Types and services.
14030 * Service Reference:: API reference.
14031 * Shepherd Services:: A particular type of service.
14034 @node Service Composition
14035 @subsubsection Service Composition
14039 Here we define a @dfn{service} as, broadly, something that extends the
14040 functionality of the operating system. Often a service is a process---a
14041 @dfn{daemon}---started when the system boots: a secure shell server, a
14042 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
14043 whose execution can be triggered by another daemon---e.g., an FTP server
14044 started by @command{inetd} or a D-Bus service activated by
14045 @command{dbus-daemon}. Occasionally, a service does not map to a
14046 daemon. For instance, the ``account'' service collects user accounts
14047 and makes sure they exist when the system runs; the ``udev'' service
14048 collects device management rules and makes them available to the eudev
14049 daemon; the @file{/etc} service populates the @file{/etc} directory
14052 @cindex service extensions
14053 GuixSD services are connected by @dfn{extensions}. For instance, the
14054 secure shell service @emph{extends} the Shepherd---the GuixSD
14055 initialization system, running as PID@tie{}1---by giving it the command
14056 lines to start and stop the secure shell daemon (@pxref{Networking
14057 Services, @code{lsh-service}}); the UPower service extends the D-Bus
14058 service by passing it its @file{.service} specification, and extends the
14059 udev service by passing it device management rules (@pxref{Desktop
14060 Services, @code{upower-service}}); the Guix daemon service extends the
14061 Shepherd by passing it the command lines to start and stop the daemon,
14062 and extends the account service by passing it a list of required build
14063 user accounts (@pxref{Base Services}).
14065 All in all, services and their ``extends'' relations form a directed
14066 acyclic graph (DAG). If we represent services as boxes and extensions
14067 as arrows, a typical system might provide something like this:
14069 @image{images/service-graph,,5in,Typical service extension graph.}
14071 @cindex system service
14072 At the bottom, we see the @dfn{system service}, which produces the
14073 directory containing everything to run and boot the system, as returned
14074 by the @command{guix system build} command. @xref{Service Reference},
14075 to learn about the other service types shown here.
14076 @xref{system-extension-graph, the @command{guix system extension-graph}
14077 command}, for information on how to generate this representation for a
14078 particular operating system definition.
14080 @cindex service types
14081 Technically, developers can define @dfn{service types} to express these
14082 relations. There can be any number of services of a given type on the
14083 system---for instance, a system running two instances of the GNU secure
14084 shell server (lsh) has two instances of @var{lsh-service-type}, with
14085 different parameters.
14087 The following section describes the programming interface for service
14088 types and services.
14090 @node Service Types and Services
14091 @subsubsection Service Types and Services
14093 A @dfn{service type} is a node in the DAG described above. Let us start
14094 with a simple example, the service type for the Guix build daemon
14095 (@pxref{Invoking guix-daemon}):
14098 (define guix-service-type
14102 (list (service-extension shepherd-root-service-type guix-shepherd-service)
14103 (service-extension account-service-type guix-accounts)
14104 (service-extension activation-service-type guix-activation)))))
14108 It defines two things:
14112 A name, whose sole purpose is to make inspection and debugging easier.
14115 A list of @dfn{service extensions}, where each extension designates the
14116 target service type and a procedure that, given the parameters of the
14117 service, returns a list of objects to extend the service of that type.
14119 Every service type has at least one service extension. The only
14120 exception is the @dfn{boot service type}, which is the ultimate service.
14123 In this example, @var{guix-service-type} extends three services:
14126 @item shepherd-root-service-type
14127 The @var{guix-shepherd-service} procedure defines how the Shepherd
14128 service is extended. Namely, it returns a @code{<shepherd-service>}
14129 object that defines how @command{guix-daemon} is started and stopped
14130 (@pxref{Shepherd Services}).
14132 @item account-service-type
14133 This extension for this service is computed by @var{guix-accounts},
14134 which returns a list of @code{user-group} and @code{user-account}
14135 objects representing the build user accounts (@pxref{Invoking
14138 @item activation-service-type
14139 Here @var{guix-activation} is a procedure that returns a gexp, which is
14140 a code snippet to run at ``activation time''---e.g., when the service is
14144 A service of this type is instantiated like this:
14147 (service guix-service-type
14148 (guix-configuration
14150 (use-substitutes? #f)))
14153 The second argument to the @code{service} form is a value representing
14154 the parameters of this specific service instance.
14155 @xref{guix-configuration-type, @code{guix-configuration}}, for
14156 information about the @code{guix-configuration} data type.
14158 @var{guix-service-type} is quite simple because it extends other
14159 services but is not extensible itself.
14161 @c @subsubsubsection Extensible Service Types
14163 The service type for an @emph{extensible} service looks like this:
14166 (define udev-service-type
14167 (service-type (name 'udev)
14169 (list (service-extension shepherd-root-service-type
14170 udev-shepherd-service)))
14172 (compose concatenate) ;concatenate the list of rules
14173 (extend (lambda (config rules)
14175 (($ <udev-configuration> udev initial-rules)
14176 (udev-configuration
14177 (udev udev) ;the udev package to use
14178 (rules (append initial-rules rules)))))))))
14181 This is the service type for the
14182 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
14183 management daemon}. Compared to the previous example, in addition to an
14184 extension of @var{shepherd-root-service-type}, we see two new fields:
14188 This is the procedure to @dfn{compose} the list of extensions to
14189 services of this type.
14191 Services can extend the udev service by passing it lists of rules; we
14192 compose those extensions simply by concatenating them.
14195 This procedure defines how the value of the service is @dfn{extended} with
14196 the composition of the extensions.
14198 Udev extensions are composed into a list of rules, but the udev service
14199 value is itself a @code{<udev-configuration>} record. So here, we
14200 extend that record by appending the list of rules it contains to the
14201 list of contributed rules.
14204 There can be only one instance of an extensible service type such as
14205 @var{udev-service-type}. If there were more, the
14206 @code{service-extension} specifications would be ambiguous.
14208 Still here? The next section provides a reference of the programming
14209 interface for services.
14211 @node Service Reference
14212 @subsubsection Service Reference
14214 We have seen an overview of service types (@pxref{Service Types and
14215 Services}). This section provides a reference on how to manipulate
14216 services and service types. This interface is provided by the
14217 @code{(gnu services)} module.
14219 @deffn {Scheme Procedure} service @var{type} @var{value}
14220 Return a new service of @var{type}, a @code{<service-type>} object (see
14221 below.) @var{value} can be any object; it represents the parameters of
14222 this particular service instance.
14225 @deffn {Scheme Procedure} service? @var{obj}
14226 Return true if @var{obj} is a service.
14229 @deffn {Scheme Procedure} service-kind @var{service}
14230 Return the type of @var{service}---i.e., a @code{<service-type>} object.
14233 @deffn {Scheme Procedure} service-parameters @var{service}
14234 Return the value associated with @var{service}. It represents its
14238 Here is an example of how a service is created and manipulated:
14242 (service nginx-service-type
14243 (nginx-configuration
14245 (log-directory log-directory)
14246 (run-directory run-directory)
14247 (file config-file))))
14252 (eq? (service-kind s) nginx-service-type)
14256 The @code{modify-services} form provides a handy way to change the
14257 parameters of some of the services of a list such as
14258 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
14259 evaluates to a list of services. Of course, you could always use
14260 standard list combinators such as @code{map} and @code{fold} to do that
14261 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
14262 @code{modify-services} simply provides a more concise form for this
14265 @deffn {Scheme Syntax} modify-services @var{services} @
14266 (@var{type} @var{variable} => @var{body}) @dots{}
14268 Modify the services listed in @var{services} according to the given
14269 clauses. Each clause has the form:
14272 (@var{type} @var{variable} => @var{body})
14275 where @var{type} is a service type---e.g.,
14276 @code{guix-service-type}---and @var{variable} is an identifier that is
14277 bound within the @var{body} to the service parameters---e.g., a
14278 @code{guix-configuration} instance---of the original service of that
14281 The @var{body} should evaluate to the new service parameters, which will
14282 be used to configure the new service. This new service will replace the
14283 original in the resulting list. Because a service's service parameters
14284 are created using @code{define-record-type*}, you can write a succinct
14285 @var{body} that evaluates to the new service parameters by using the
14286 @code{inherit} feature that @code{define-record-type*} provides.
14288 @xref{Using the Configuration System}, for example usage.
14292 Next comes the programming interface for service types. This is
14293 something you want to know when writing new service definitions, but not
14294 necessarily when simply looking for ways to customize your
14295 @code{operating-system} declaration.
14297 @deftp {Data Type} service-type
14298 @cindex service type
14299 This is the representation of a @dfn{service type} (@pxref{Service Types
14304 This is a symbol, used only to simplify inspection and debugging.
14306 @item @code{extensions}
14307 A non-empty list of @code{<service-extension>} objects (see below).
14309 @item @code{compose} (default: @code{#f})
14310 If this is @code{#f}, then the service type denotes services that cannot
14311 be extended---i.e., services that do not receive ``values'' from other
14314 Otherwise, it must be a one-argument procedure. The procedure is called
14315 by @code{fold-services} and is passed a list of values collected from
14316 extensions. It must return a value that is a valid parameter value for
14317 the service instance.
14319 @item @code{extend} (default: @code{#f})
14320 If this is @code{#f}, services of this type cannot be extended.
14322 Otherwise, it must be a two-argument procedure: @code{fold-services}
14323 calls it, passing it the initial value of the service as the first argument
14324 and the result of applying @code{compose} to the extension values as the
14328 @xref{Service Types and Services}, for examples.
14331 @deffn {Scheme Procedure} service-extension @var{target-type} @
14333 Return a new extension for services of type @var{target-type}.
14334 @var{compute} must be a one-argument procedure: @code{fold-services}
14335 calls it, passing it the value associated with the service that provides
14336 the extension; it must return a valid value for the target service.
14339 @deffn {Scheme Procedure} service-extension? @var{obj}
14340 Return true if @var{obj} is a service extension.
14343 Occasionally, you might want to simply extend an existing service. This
14344 involves creating a new service type and specifying the extension of
14345 interest, which can be verbose; the @code{simple-service} procedure
14346 provides a shorthand for this.
14348 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
14349 Return a service that extends @var{target} with @var{value}. This works
14350 by creating a singleton service type @var{name}, of which the returned
14351 service is an instance.
14353 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
14357 (simple-service 'my-mcron-job mcron-service-type
14358 #~(job '(next-hour (3)) "guix gc -F 2G"))
14362 At the core of the service abstraction lies the @code{fold-services}
14363 procedure, which is responsible for ``compiling'' a list of services
14364 down to a single directory that contains everything needed to boot and
14365 run the system---the directory shown by the @command{guix system build}
14366 command (@pxref{Invoking guix system}). In essence, it propagates
14367 service extensions down the service graph, updating each node parameters
14368 on the way, until it reaches the root node.
14370 @deffn {Scheme Procedure} fold-services @var{services} @
14371 [#:target-type @var{system-service-type}]
14372 Fold @var{services} by propagating their extensions down to the root of
14373 type @var{target-type}; return the root service adjusted accordingly.
14376 Lastly, the @code{(gnu services)} module also defines several essential
14377 service types, some of which are listed below.
14379 @defvr {Scheme Variable} system-service-type
14380 This is the root of the service graph. It produces the system directory
14381 as returned by the @command{guix system build} command.
14384 @defvr {Scheme Variable} boot-service-type
14385 The type of the ``boot service'', which produces the @dfn{boot script}.
14386 The boot script is what the initial RAM disk runs when booting.
14389 @defvr {Scheme Variable} etc-service-type
14390 The type of the @file{/etc} service. This service can be extended by
14391 passing it name/file tuples such as:
14394 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
14397 In this example, the effect would be to add an @file{/etc/issue} file
14398 pointing to the given file.
14401 @defvr {Scheme Variable} setuid-program-service-type
14402 Type for the ``setuid-program service''. This service collects lists of
14403 executable file names, passed as gexps, and adds them to the set of
14404 setuid-root programs on the system (@pxref{Setuid Programs}).
14407 @defvr {Scheme Variable} profile-service-type
14408 Type of the service that populates the @dfn{system profile}---i.e., the
14409 programs under @file{/run/current-system/profile}. Other services can
14410 extend it by passing it lists of packages to add to the system profile.
14414 @node Shepherd Services
14415 @subsubsection Shepherd Services
14417 @cindex shepherd services
14419 @cindex init system
14420 The @code{(gnu services shepherd)} module provides a way to define
14421 services managed by the GNU@tie{}Shepherd, which is the GuixSD
14422 initialization system---the first process that is started when the
14423 system boots, also known as PID@tie{}1
14424 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
14426 Services in the Shepherd can depend on each other. For instance, the
14427 SSH daemon may need to be started after the syslog daemon has been
14428 started, which in turn can only happen once all the file systems have
14429 been mounted. The simple operating system defined earlier (@pxref{Using
14430 the Configuration System}) results in a service graph like this:
14432 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
14434 You can actually generate such a graph for any operating system
14435 definition using the @command{guix system shepherd-graph} command
14436 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
14438 The @var{%shepherd-root-service} is a service object representing
14439 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
14440 by passing it lists of @code{<shepherd-service>} objects.
14442 @deftp {Data Type} shepherd-service
14443 The data type representing a service managed by the Shepherd.
14446 @item @code{provision}
14447 This is a list of symbols denoting what the service provides.
14449 These are the names that may be passed to @command{herd start},
14450 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
14451 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
14452 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
14454 @item @code{requirements} (default: @code{'()})
14455 List of symbols denoting the Shepherd services this one depends on.
14457 @item @code{respawn?} (default: @code{#t})
14458 Whether to restart the service when it stops, for instance when the
14459 underlying process dies.
14462 @itemx @code{stop} (default: @code{#~(const #f)})
14463 The @code{start} and @code{stop} fields refer to the Shepherd's
14464 facilities to start and stop processes (@pxref{Service De- and
14465 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
14466 G-expressions that get expanded in the Shepherd configuration file
14467 (@pxref{G-Expressions}).
14469 @item @code{documentation}
14470 A documentation string, as shown when running:
14473 herd doc @var{service-name}
14476 where @var{service-name} is one of the symbols in @var{provision}
14477 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
14479 @item @code{modules} (default: @var{%default-modules})
14480 This is the list of modules that must be in scope when @code{start} and
14481 @code{stop} are evaluated.
14486 @defvr {Scheme Variable} shepherd-root-service-type
14487 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
14489 This is the service type that extensions target when they want to create
14490 shepherd services (@pxref{Service Types and Services}, for an example).
14491 Each extension must pass a list of @code{<shepherd-service>}.
14494 @defvr {Scheme Variable} %shepherd-root-service
14495 This service represents PID@tie{}1.
14499 @node Installing Debugging Files
14500 @section Installing Debugging Files
14502 @cindex debugging files
14503 Program binaries, as produced by the GCC compilers for instance, are
14504 typically written in the ELF format, with a section containing
14505 @dfn{debugging information}. Debugging information is what allows the
14506 debugger, GDB, to map binary code to source code; it is required to
14507 debug a compiled program in good conditions.
14509 The problem with debugging information is that is takes up a fair amount
14510 of disk space. For example, debugging information for the GNU C Library
14511 weighs in at more than 60 MiB. Thus, as a user, keeping all the
14512 debugging info of all the installed programs is usually not an option.
14513 Yet, space savings should not come at the cost of an impediment to
14514 debugging---especially in the GNU system, which should make it easier
14515 for users to exert their computing freedom (@pxref{GNU Distribution}).
14517 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
14518 mechanism that allows users to get the best of both worlds: debugging
14519 information can be stripped from the binaries and stored in separate
14520 files. GDB is then able to load debugging information from those files,
14521 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
14524 The GNU distribution takes advantage of this by storing debugging
14525 information in the @code{lib/debug} sub-directory of a separate package
14526 output unimaginatively called @code{debug} (@pxref{Packages with
14527 Multiple Outputs}). Users can choose to install the @code{debug} output
14528 of a package when they need it. For instance, the following command
14529 installs the debugging information for the GNU C Library and for GNU
14533 guix package -i glibc:debug guile:debug
14536 GDB must then be told to look for debug files in the user's profile, by
14537 setting the @code{debug-file-directory} variable (consider setting it
14538 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
14542 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
14545 From there on, GDB will pick up debugging information from the
14546 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
14548 In addition, you will most likely want GDB to be able to show the source
14549 code being debugged. To do that, you will have to unpack the source
14550 code of the package of interest (obtained with @code{guix build
14551 --source}, @pxref{Invoking guix build}), and to point GDB to that source
14552 directory using the @code{directory} command (@pxref{Source Path,
14553 @code{directory},, gdb, Debugging with GDB}).
14555 @c XXX: keep me up-to-date
14556 The @code{debug} output mechanism in Guix is implemented by the
14557 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
14558 opt-in---debugging information is available only for the packages
14559 with definitions explicitly declaring a @code{debug} output. This may be
14560 changed to opt-out in the future if our build farm servers can handle
14561 the load. To check whether a package has a @code{debug} output, use
14562 @command{guix package --list-available} (@pxref{Invoking guix package}).
14565 @node Security Updates
14566 @section Security Updates
14568 @cindex security updates
14569 @cindex security vulnerabilities
14570 Occasionally, important security vulnerabilities are discovered in software
14571 packages and must be patched. Guix developers try hard to keep track of
14572 known vulnerabilities and to apply fixes as soon as possible in the
14573 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
14574 containing only security updates.) The @command{guix lint} tool helps
14575 developers find out about vulnerable versions of software packages in the
14580 gnu/packages/base.scm:652:2: glibc-2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
14581 gnu/packages/gcc.scm:334:2: gcc-4.9.3: probably vulnerable to CVE-2015-5276
14582 gnu/packages/image.scm:312:2: openjpeg-2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
14586 @xref{Invoking guix lint}, for more information.
14589 As of version @value{VERSION}, the feature described below is considered
14593 Guix follows a functional
14594 package management discipline (@pxref{Introduction}), which implies
14595 that, when a package is changed, @emph{every package that depends on it}
14596 must be rebuilt. This can significantly slow down the deployment of
14597 fixes in core packages such as libc or Bash, since basically the whole
14598 distribution would need to be rebuilt. Using pre-built binaries helps
14599 (@pxref{Substitutes}), but deployment may still take more time than
14603 To address this, Guix implements @dfn{grafts}, a mechanism that allows
14604 for fast deployment of critical updates without the costs associated
14605 with a whole-distribution rebuild. The idea is to rebuild only the
14606 package that needs to be patched, and then to ``graft'' it onto packages
14607 explicitly installed by the user and that were previously referring to
14608 the original package. The cost of grafting is typically very low, and
14609 order of magnitudes lower than a full rebuild of the dependency chain.
14611 @cindex replacements of packages, for grafts
14612 For instance, suppose a security update needs to be applied to Bash.
14613 Guix developers will provide a package definition for the ``fixed''
14614 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
14615 Packages}). Then, the original package definition is augmented with a
14616 @code{replacement} field pointing to the package containing the bug fix:
14623 (replacement bash-fixed)))
14626 From there on, any package depending directly or indirectly on Bash---as
14627 reported by @command{guix gc --requisites} (@pxref{Invoking guix
14628 gc})---that is installed is automatically ``rewritten'' to refer to
14629 @var{bash-fixed} instead of @var{bash}. This grafting process takes
14630 time proportional to the size of the package, usually less than a
14631 minute for an ``average'' package on a recent machine. Grafting is
14632 recursive: when an indirect dependency requires grafting, then grafting
14633 ``propagates'' up to the package that the user is installing.
14635 Currently, the length of the name and version of the graft and that of
14636 the package it replaces (@var{bash-fixed} and @var{bash} in the example
14637 above) must be equal. This restriction mostly comes from the fact that
14638 grafting works by patching files, including binary files, directly.
14639 Other restrictions may apply: for instance, when adding a graft to a
14640 package providing a shared library, the original shared library and its
14641 replacement must have the same @code{SONAME} and be binary-compatible.
14643 The @option{--no-grafts} command-line option allows you to forcefully
14644 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
14648 guix build bash --no-grafts
14652 returns the store file name of the original Bash, whereas:
14659 returns the store file name of the ``fixed'', replacement Bash. This
14660 allows you to distinguish between the two variants of Bash.
14662 To verify which Bash your whole profile refers to, you can run
14663 (@pxref{Invoking guix gc}):
14666 guix gc -R `readlink -f ~/.guix-profile` | grep bash
14670 @dots{} and compare the store file names that you get with those above.
14671 Likewise for a complete GuixSD system generation:
14674 guix gc -R `guix system build my-config.scm` | grep bash
14677 Lastly, to check which Bash running processes are using, you can use the
14678 @command{lsof} command:
14681 lsof | grep /gnu/store/.*bash
14685 @node Package Modules
14686 @section Package Modules
14688 From a programming viewpoint, the package definitions of the
14689 GNU distribution are provided by Guile modules in the @code{(gnu packages
14690 @dots{})} name space@footnote{Note that packages under the @code{(gnu
14691 packages @dots{})} module name space are not necessarily ``GNU
14692 packages''. This module naming scheme follows the usual Guile module
14693 naming convention: @code{gnu} means that these modules are distributed
14694 as part of the GNU system, and @code{packages} identifies modules that
14695 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
14696 Reference Manual}). For instance, the @code{(gnu packages emacs)}
14697 module exports a variable named @code{emacs}, which is bound to a
14698 @code{<package>} object (@pxref{Defining Packages}).
14700 The @code{(gnu packages @dots{})} module name space is
14701 automatically scanned for packages by the command-line tools. For
14702 instance, when running @code{guix package -i emacs}, all the @code{(gnu
14703 packages @dots{})} modules are scanned until one that exports a package
14704 object whose name is @code{emacs} is found. This package search
14705 facility is implemented in the @code{(gnu packages)} module.
14707 @cindex customization, of packages
14708 @cindex package module search path
14709 Users can store package definitions in modules with different
14710 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
14711 name and module name must match. For instance, the @code{(my-packages
14712 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
14713 relative to the load path specified with @option{--load-path} or
14714 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
14715 guile, GNU Guile Reference Manual}, for details.}. These package definitions
14716 will not be visible by default. Users can invoke commands such as
14717 @command{guix package} and @command{guix build} with the
14718 @code{-e} option so that they know where to find the package. Better
14719 yet, they can use the
14720 @code{-L} option of these commands to make those modules visible
14721 (@pxref{Invoking guix build, @code{--load-path}}), or define the
14722 @code{GUIX_PACKAGE_PATH} environment variable. This environment
14723 variable makes it easy to extend or customize the distribution and is
14724 honored by all the user interfaces.
14726 @defvr {Environment Variable} GUIX_PACKAGE_PATH
14727 This is a colon-separated list of directories to search for additional
14728 package modules. Directories listed in this variable take precedence
14729 over the own modules of the distribution.
14732 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
14733 each package is built based solely on other packages in the
14734 distribution. The root of this dependency graph is a small set of
14735 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
14736 bootstrap)} module. For more information on bootstrapping,
14737 @pxref{Bootstrapping}.
14739 @node Packaging Guidelines
14740 @section Packaging Guidelines
14742 @cindex packages, creating
14743 The GNU distribution is nascent and may well lack some of your favorite
14744 packages. This section describes how you can help make the distribution
14745 grow. @xref{Contributing}, for additional information on how you can
14748 Free software packages are usually distributed in the form of
14749 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
14750 all the source files. Adding a package to the distribution means
14751 essentially two things: adding a @dfn{recipe} that describes how to
14752 build the package, including a list of other packages required to build
14753 it, and adding @dfn{package metadata} along with that recipe, such as a
14754 description and licensing information.
14756 In Guix all this information is embodied in @dfn{package definitions}.
14757 Package definitions provide a high-level view of the package. They are
14758 written using the syntax of the Scheme programming language; in fact,
14759 for each package we define a variable bound to the package definition,
14760 and export that variable from a module (@pxref{Package Modules}).
14761 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
14762 creating packages. For more information on package definitions,
14763 @pxref{Defining Packages}.
14765 Once a package definition is in place, stored in a file in the Guix
14766 source tree, it can be tested using the @command{guix build} command
14767 (@pxref{Invoking guix build}). For example, assuming the new package is
14768 called @code{gnew}, you may run this command from the Guix build tree
14769 (@pxref{Running Guix Before It Is Installed}):
14772 ./pre-inst-env guix build gnew --keep-failed
14775 Using @code{--keep-failed} makes it easier to debug build failures since
14776 it provides access to the failed build tree. Another useful
14777 command-line option when debugging is @code{--log-file}, to access the
14780 If the package is unknown to the @command{guix} command, it may be that
14781 the source file contains a syntax error, or lacks a @code{define-public}
14782 clause to export the package variable. To figure it out, you may load
14783 the module from Guile to get more information about the actual error:
14786 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
14789 Once your package builds correctly, please send us a patch
14790 (@pxref{Contributing}). Well, if you need help, we will be happy to
14791 help you too. Once the patch is committed in the Guix repository, the
14792 new package automatically gets built on the supported platforms by
14793 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
14796 @cindex substituter
14797 Users can obtain the new package definition simply by running
14798 @command{guix pull} (@pxref{Invoking guix pull}). When
14799 @code{hydra.gnu.org} is done building the package, installing the
14800 package automatically downloads binaries from there
14801 (@pxref{Substitutes}). The only place where human intervention is
14802 needed is to review and apply the patch.
14806 * Software Freedom:: What may go into the distribution.
14807 * Package Naming:: What's in a name?
14808 * Version Numbers:: When the name is not enough.
14809 * Synopses and Descriptions:: Helping users find the right package.
14810 * Python Modules:: Taming the snake.
14811 * Perl Modules:: Little pearls.
14812 * Java Packages:: Coffee break.
14813 * Fonts:: Fond of fonts.
14816 @node Software Freedom
14817 @subsection Software Freedom
14819 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
14820 @cindex free software
14821 The GNU operating system has been developed so that users can have
14822 freedom in their computing. GNU is @dfn{free software}, meaning that
14823 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
14824 essential freedoms}: to run the program, to study and change the program
14825 in source code form, to redistribute exact copies, and to distribute
14826 modified versions. Packages found in the GNU distribution provide only
14827 software that conveys these four freedoms.
14829 In addition, the GNU distribution follow the
14830 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
14831 software distribution guidelines}. Among other things, these guidelines
14832 reject non-free firmware, recommendations of non-free software, and
14833 discuss ways to deal with trademarks and patents.
14835 Some otherwise free upstream package sources contain a small and optional
14836 subset that violates the above guidelines, for instance because this subset
14837 is itself non-free code. When that happens, the offending items are removed
14838 with appropriate patches or code snippets in the @code{origin} form of the
14839 package (@pxref{Defining Packages}). This way, @code{guix
14840 build --source} returns the ``freed'' source rather than the unmodified
14844 @node Package Naming
14845 @subsection Package Naming
14847 @cindex package name
14848 A package has actually two names associated with it:
14849 First, there is the name of the @emph{Scheme variable}, the one following
14850 @code{define-public}. By this name, the package can be made known in the
14851 Scheme code, for instance as input to another package. Second, there is
14852 the string in the @code{name} field of a package definition. This name
14853 is used by package management commands such as
14854 @command{guix package} and @command{guix build}.
14856 Both are usually the same and correspond to the lowercase conversion of
14857 the project name chosen upstream, with underscores replaced with
14858 hyphens. For instance, GNUnet is available as @code{gnunet}, and
14859 SDL_net as @code{sdl-net}.
14861 We do not add @code{lib} prefixes for library packages, unless these are
14862 already part of the official project name. But @pxref{Python
14863 Modules} and @ref{Perl Modules} for special rules concerning modules for
14864 the Python and Perl languages.
14866 Font package names are handled differently, @pxref{Fonts}.
14869 @node Version Numbers
14870 @subsection Version Numbers
14872 @cindex package version
14873 We usually package only the latest version of a given free software
14874 project. But sometimes, for instance for incompatible library versions,
14875 two (or more) versions of the same package are needed. These require
14876 different Scheme variable names. We use the name as defined
14877 in @ref{Package Naming}
14878 for the most recent version; previous versions use the same name, suffixed
14879 by @code{-} and the smallest prefix of the version number that may
14880 distinguish the two versions.
14882 The name inside the package definition is the same for all versions of a
14883 package and does not contain any version number.
14885 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
14888 (define-public gtk+
14893 (define-public gtk+-2
14896 (version "2.24.20")
14899 If we also wanted GTK+ 3.8.2, this would be packaged as
14901 (define-public gtk+-3.8
14908 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
14909 @c for a discussion of what follows.
14910 @cindex version number, for VCS snapshots
14911 Occasionally, we package snapshots of upstream's version control system
14912 (VCS) instead of formal releases. This should remain exceptional,
14913 because it is up to upstream developers to clarify what the stable
14914 release is. Yet, it is sometimes necessary. So, what should we put in
14915 the @code{version} field?
14917 Clearly, we need to make the commit identifier of the VCS snapshot
14918 visible in the version string, but we also need to make sure that the
14919 version string is monotonically increasing so that @command{guix package
14920 --upgrade} can determine which version is newer. Since commit
14921 identifiers, notably with Git, are not monotonically increasing, we add
14922 a revision number that we increase each time we upgrade to a newer
14923 snapshot. The resulting version string looks like this:
14928 | | `-- upstream commit ID
14930 | `--- Guix package revision
14932 latest upstream version
14935 It is a good idea to strip commit identifiers in the @code{version}
14936 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
14937 aesthetics have a role to play here) as well as problems related to OS
14938 limits such as the maximum shebang length (127 bytes for the Linux
14939 kernel.) It is best to use the full commit identifiers in
14940 @code{origin}s, though, to avoid ambiguities. A typical package
14941 definition may look like this:
14945 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
14946 (revision "1")) ;Guix package revision
14948 (version (string-append "0.9-" revision "."
14949 (string-take commit 7)))
14952 (uri (git-reference
14953 (url "git://example.org/my-package.git")
14955 (sha256 (base32 "1mbikn@dots{}"))
14956 (file-name (string-append "my-package-" version
14962 @node Synopses and Descriptions
14963 @subsection Synopses and Descriptions
14965 @cindex package description
14966 @cindex package synopsis
14967 As we have seen before, each package in GNU@tie{}Guix includes a
14968 synopsis and a description (@pxref{Defining Packages}). Synopses and
14969 descriptions are important: They are what @command{guix package
14970 --search} searches, and a crucial piece of information to help users
14971 determine whether a given package suits their needs. Consequently,
14972 packagers should pay attention to what goes into them.
14974 Synopses must start with a capital letter and must not end with a
14975 period. They must not start with ``a'' or ``the'', which usually does
14976 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
14977 tool that frobs files''. The synopsis should say what the package
14978 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
14979 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
14980 matching a pattern''.
14982 Keep in mind that the synopsis must be meaningful for a very wide
14983 audience. For example, ``Manipulate alignments in the SAM format''
14984 might make sense for a seasoned bioinformatics researcher, but might be
14985 fairly unhelpful or even misleading to a non-specialized audience. It
14986 is a good idea to come up with a synopsis that gives an idea of the
14987 application domain of the package. In this example, this might give
14988 something like ``Manipulate nucleotide sequence alignments'', which
14989 hopefully gives the user a better idea of whether this is what they are
14992 Descriptions should take between five and ten lines. Use full
14993 sentences, and avoid using acronyms without first introducing them.
14994 Please avoid marketing phrases such as ``world-leading'',
14995 ``industrial-strength'', and ``next-generation'', and avoid superlatives
14996 like ``the most advanced''---they are not helpful to users looking for a
14997 package and may even sound suspicious. Instead, try to be factual,
14998 mentioning use cases and features.
15000 @cindex Texinfo markup, in package descriptions
15001 Descriptions can include Texinfo markup, which is useful to introduce
15002 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
15003 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
15004 should be careful when using some characters for example @samp{@@} and
15005 curly braces which are the basic special characters in Texinfo
15006 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
15007 such as @command{guix package --show} take care of rendering it
15010 Synopses and descriptions are translated by volunteers
15011 @uref{http://translationproject.org/domain/guix-packages.html, at the
15012 Translation Project} so that as many users as possible can read them in
15013 their native language. User interfaces search them and display them in
15014 the language specified by the current locale.
15016 Translation is a lot of work so, as a packager, please pay even more
15017 attention to your synopses and descriptions as every change may entail
15018 additional work for translators. In order to help them, it is possible
15019 to make recommendations or instructions visible to them by inserting
15020 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
15024 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
15025 (description "ARandR is designed to provide a simple visual front end
15026 for the X11 resize-and-rotate (RandR) extension. @dots{}")
15030 @node Python Modules
15031 @subsection Python Modules
15034 We currently package Python 2 and Python 3, under the Scheme variable names
15035 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
15036 To avoid confusion and naming clashes with other programming languages, it
15037 seems desirable that the name of a package for a Python module contains
15038 the word @code{python}.
15040 Some modules are compatible with only one version of Python, others with both.
15041 If the package Foo compiles only with Python 3, we name it
15042 @code{python-foo}; if it compiles only with Python 2, we name it
15043 @code{python2-foo}. If it is compatible with both versions, we create two
15044 packages with the corresponding names.
15046 If a project already contains the word @code{python}, we drop this;
15047 for instance, the module python-dateutil is packaged under the names
15048 @code{python-dateutil} and @code{python2-dateutil}. If the project name
15049 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
15052 @subsubsection Specifying Dependencies
15053 @cindex inputs, for Python packages
15055 Dependency information for Python packages is usually available in the
15056 package source tree, with varying degrees of accuracy: in the
15057 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
15059 Your mission, when writing a recipe for a Python package, is to map
15060 these dependencies to the appropriate type of ``input'' (@pxref{package
15061 Reference, inputs}). Although the @code{pypi} importer normally does a
15062 good job (@pxref{Invoking guix import}), you may want to check the
15063 following check list to determine which dependency goes where.
15068 We currently package Python 2 with @code{setuptools} and @code{pip}
15069 installed like Python 3.4 has per default. Thus you don't need to
15070 specify either of these as an input. @command{guix lint} will warn you
15074 Python dependencies required at run time go into
15075 @code{propagated-inputs}. They are typically defined with the
15076 @code{install_requires} keyword in @file{setup.py}, or in the
15077 @file{requirements.txt} file.
15080 Python packages required only at build time---e.g., those listed with
15081 the @code{setup_requires} keyword in @file{setup.py}---or only for
15082 testing---e.g., those in @code{tests_require}---go into
15083 @code{native-inputs}. The rationale is that (1) they do not need to be
15084 propagated because they are not needed at run time, and (2) in a
15085 cross-compilation context, it's the ``native'' input that we'd want.
15087 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
15088 frameworks. Of course if any of these packages is also required at
15089 run-time, it needs to go to @code{propagated-inputs}.
15092 Anything that does not fall in the previous categories goes to
15093 @code{inputs}, for example programs or C libraries required for building
15094 Python packages containing C extensions.
15097 If a Python package has optional dependencies (@code{extras_require}),
15098 it is up to you to decide whether to add them or not, based on their
15099 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
15106 @subsection Perl Modules
15109 Perl programs standing for themselves are named as any other package,
15110 using the lowercase upstream name.
15111 For Perl packages containing a single class, we use the lowercase class name,
15112 replace all occurrences of @code{::} by dashes and prepend the prefix
15114 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
15115 Modules containing several classes keep their lowercase upstream name and
15116 are also prepended by @code{perl-}. Such modules tend to have the word
15117 @code{perl} somewhere in their name, which gets dropped in favor of the
15118 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
15121 @node Java Packages
15122 @subsection Java Packages
15125 Java programs standing for themselves are named as any other package,
15126 using the lowercase upstream name.
15128 To avoid confusion and naming clashes with other programming languages,
15129 it is desirable that the name of a package for a Java package is
15130 prefixed with @code{java-}. If a project already contains the word
15131 @code{java}, we drop this; for instance, the package @code{ngsjava} is
15132 packaged under the name @code{java-ngs}.
15134 For Java packages containing a single class or a small class hierarchy,
15135 we use the lowercase class name, replace all occurrences of @code{.} by
15136 dashes and prepend the prefix @code{java-}. So the class
15137 @code{apache.commons.cli} becomes package
15138 @code{java-apache-commons-cli}.
15145 For fonts that are in general not installed by a user for typesetting
15146 purposes, or that are distributed as part of a larger software package,
15147 we rely on the general packaging rules for software; for instance, this
15148 applies to the fonts delivered as part of the X.Org system or fonts that
15149 are part of TeX Live.
15151 To make it easier for a user to search for fonts, names for other packages
15152 containing only fonts are constructed as follows, independently of the
15153 upstream package name.
15155 The name of a package containing only one font family starts with
15156 @code{font-}; it is followed by the foundry name and a dash @code{-}
15157 if the foundry is known, and the font family name, in which spaces are
15158 replaced by dashes (and as usual, all upper case letters are transformed
15160 For example, the Gentium font family by SIL is packaged under the name
15161 @code{font-sil-gentium}.
15163 For a package containing several font families, the name of the collection
15164 is used in the place of the font family name.
15165 For instance, the Liberation fonts consist of three families,
15166 Liberation Sans, Liberation Serif and Liberation Mono.
15167 These could be packaged separately under the names
15168 @code{font-liberation-sans} and so on; but as they are distributed together
15169 under a common name, we prefer to package them together as
15170 @code{font-liberation}.
15172 In the case where several formats of the same font family or font collection
15173 are packaged separately, a short form of the format, prepended by a dash,
15174 is added to the package name. We use @code{-ttf} for TrueType fonts,
15175 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
15180 @node Bootstrapping
15181 @section Bootstrapping
15183 @c Adapted from the ELS 2013 paper.
15185 @cindex bootstrapping
15187 Bootstrapping in our context refers to how the distribution gets built
15188 ``from nothing''. Remember that the build environment of a derivation
15189 contains nothing but its declared inputs (@pxref{Introduction}). So
15190 there's an obvious chicken-and-egg problem: how does the first package
15191 get built? How does the first compiler get compiled? Note that this is
15192 a question of interest only to the curious hacker, not to the regular
15193 user, so you can shamelessly skip this section if you consider yourself
15194 a ``regular user''.
15196 @cindex bootstrap binaries
15197 The GNU system is primarily made of C code, with libc at its core. The
15198 GNU build system itself assumes the availability of a Bourne shell and
15199 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
15200 `grep'. Furthermore, build programs---programs that run
15201 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
15202 (@pxref{Derivations}). Consequently, to be able to build anything at
15203 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
15204 Binutils, libc, and the other packages mentioned above---the
15205 @dfn{bootstrap binaries}.
15207 These bootstrap binaries are ``taken for granted'', though we can also
15208 re-create them if needed (more on that later).
15210 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
15212 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
15213 @c large image, it's hard to scroll. Oh well.
15214 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
15216 The figure above shows the very beginning of the dependency graph of the
15217 distribution, corresponding to the package definitions of the @code{(gnu
15218 packages bootstrap)} module. A similar figure can be generated with
15219 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
15222 guix graph -t derivation \
15223 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
15227 At this level of detail, things are
15228 slightly complex. First, Guile itself consists of an ELF executable,
15229 along with many source and compiled Scheme files that are dynamically
15230 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
15231 tarball shown in this graph. This tarball is part of Guix's ``source''
15232 distribution, and gets inserted into the store with @code{add-to-store}
15233 (@pxref{The Store}).
15235 But how do we write a derivation that unpacks this tarball and adds it
15236 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
15237 derivation---the first one that gets built---uses @code{bash} as its
15238 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
15239 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
15240 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
15241 the Guix source distribution, whose sole purpose is to allow the Guile
15242 tarball to be unpacked.
15244 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
15245 Guile that can be used to run subsequent build programs. Its first task
15246 is to download tarballs containing the other pre-built binaries---this
15247 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
15248 @code{ftp-client.scm} are used for this purpose. The
15249 @code{module-import.drv} derivations import those modules in a directory
15250 in the store, using the original layout. The
15251 @code{module-import-compiled.drv} derivations compile those modules, and
15252 write them in an output directory with the right layout. This
15253 corresponds to the @code{#:modules} argument of
15254 @code{build-expression->derivation} (@pxref{Derivations}).
15256 Finally, the various tarballs are unpacked by the
15257 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
15258 etc., at which point we have a working C tool chain.
15261 @unnumberedsubsec Building the Build Tools
15263 Bootstrapping is complete when we have a full tool chain that does not
15264 depend on the pre-built bootstrap tools discussed above. This
15265 no-dependency requirement is verified by checking whether the files of
15266 the final tool chain contain references to the @file{/gnu/store}
15267 directories of the bootstrap inputs. The process that leads to this
15268 ``final'' tool chain is described by the package definitions found in
15269 the @code{(gnu packages commencement)} module.
15271 The @command{guix graph} command allows us to ``zoom out'' compared to
15272 the graph above, by looking at the level of package objects instead of
15273 individual derivations---remember that a package may translate to
15274 several derivations, typically one derivation to download its source,
15275 one to build the Guile modules it needs, and one to actually build the
15276 package from source. The command:
15279 guix graph -t bag \
15280 -e '(@@@@ (gnu packages commencement)
15281 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
15285 produces the dependency graph leading to the ``final'' C
15286 library@footnote{You may notice the @code{glibc-intermediate} label,
15287 suggesting that it is not @emph{quite} final, but as a good
15288 approximation, we will consider it final.}, depicted below.
15290 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
15292 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
15293 The first tool that gets built with the bootstrap binaries is
15294 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
15295 for all the following packages. From there Findutils and Diffutils get
15298 Then come the first-stage Binutils and GCC, built as pseudo cross
15299 tools---i.e., with @code{--target} equal to @code{--host}. They are
15300 used to build libc. Thanks to this cross-build trick, this libc is
15301 guaranteed not to hold any reference to the initial tool chain.
15303 From there the final Binutils and GCC (not shown above) are built.
15305 from the final Binutils, and links programs against the just-built libc.
15306 This tool chain is used to build the other packages used by Guix and by
15307 the GNU Build System: Guile, Bash, Coreutils, etc.
15309 And voilà! At this point we have the complete set of build tools that
15310 the GNU Build System expects. These are in the @code{%final-inputs}
15311 variable of the @code{(gnu packages commencement)} module, and are
15312 implicitly used by any package that uses @code{gnu-build-system}
15313 (@pxref{Build Systems, @code{gnu-build-system}}).
15316 @unnumberedsubsec Building the Bootstrap Binaries
15318 @cindex bootstrap binaries
15319 Because the final tool chain does not depend on the bootstrap binaries,
15320 those rarely need to be updated. Nevertheless, it is useful to have an
15321 automated way to produce them, should an update occur, and this is what
15322 the @code{(gnu packages make-bootstrap)} module provides.
15324 The following command builds the tarballs containing the bootstrap
15325 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
15326 of Coreutils and other basic command-line tools):
15329 guix build bootstrap-tarballs
15332 The generated tarballs are those that should be referred to in the
15333 @code{(gnu packages bootstrap)} module mentioned at the beginning of
15336 Still here? Then perhaps by now you've started to wonder: when do we
15337 reach a fixed point? That is an interesting question! The answer is
15338 unknown, but if you would like to investigate further (and have
15339 significant computational and storage resources to do so), then let us
15343 @section Porting to a New Platform
15345 As discussed above, the GNU distribution is self-contained, and
15346 self-containment is achieved by relying on pre-built ``bootstrap
15347 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
15348 operating system kernel, CPU architecture, and application binary
15349 interface (ABI). Thus, to port the distribution to a platform that is
15350 not yet supported, one must build those bootstrap binaries, and update
15351 the @code{(gnu packages bootstrap)} module to use them on that platform.
15353 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
15354 When everything goes well, and assuming the GNU tool chain supports the
15355 target platform, this can be as simple as running a command like this
15359 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
15362 For this to work, the @code{glibc-dynamic-linker} procedure in
15363 @code{(gnu packages bootstrap)} must be augmented to return the right
15364 file name for libc's dynamic linker on that platform; likewise,
15365 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
15366 taught about the new platform.
15368 Once these are built, the @code{(gnu packages bootstrap)} module needs
15369 to be updated to refer to these binaries on the target platform. That
15370 is, the hashes and URLs of the bootstrap tarballs for the new platform
15371 must be added alongside those of the currently supported platforms. The
15372 bootstrap Guile tarball is treated specially: it is expected to be
15373 available locally, and @file{gnu/local.mk} has rules do download it for
15374 the supported architectures; a rule for the new platform must be added
15377 In practice, there may be some complications. First, it may be that the
15378 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
15379 above) is not recognized by all the GNU tools. Typically, glibc
15380 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
15381 configure flag (see @code{gcc.scm} for examples of how to handle this).
15382 Second, some of the required packages could fail to build for that
15383 platform. Lastly, the generated binaries could be broken for some
15386 @c *********************************************************************
15387 @include contributing.texi
15389 @c *********************************************************************
15390 @node Acknowledgments
15391 @chapter Acknowledgments
15393 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
15394 which was designed and
15395 implemented by Eelco Dolstra, with contributions from other people (see
15396 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
15397 management, and promoted unprecedented features, such as transactional
15398 package upgrades and rollbacks, per-user profiles, and referentially
15399 transparent build processes. Without this work, Guix would not exist.
15401 The Nix-based software distributions, Nixpkgs and NixOS, have also been
15402 an inspiration for Guix.
15404 GNU@tie{}Guix itself is a collective work with contributions from a
15405 number of people. See the @file{AUTHORS} file in Guix for more
15406 information on these fine people. The @file{THANKS} file lists people
15407 who have helped by reporting bugs, taking care of the infrastructure,
15408 providing artwork and themes, making suggestions, and more---thank you!
15411 @c *********************************************************************
15412 @node GNU Free Documentation License
15413 @appendix GNU Free Documentation License
15414 @cindex license, GNU Free Documentation License
15415 @include fdl-1.3.texi
15417 @c *********************************************************************
15418 @node Concept Index
15419 @unnumbered Concept Index
15422 @node Programming Index
15423 @unnumbered Programming Index
15424 @syncodeindex tp fn
15425 @syncodeindex vr fn
15430 @c Local Variables:
15431 @c ispell-local-dictionary: "american";