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, 2017 Efraim Flashner@*
28 Copyright @copyright{} 2016 John Darrington@*
29 Copyright @copyright{} 2016 ng0@*
30 Copyright @copyright{} 2016 Jan Nieuwenhuizen@*
31 Copyright @copyright{} 2016 Julien Lepiller@*
32 Copyright @copyright{} 2016 Alex ter Weele@*
33 Copyright @copyright{} 2017 Clément Lassieur@*
34 Copyright @copyright{} 2017 Mathieu Othacehe@*
35 Copyright @copyright{} 2017 Federico Beffa@*
36 Copyright @copyright{} 2017 Carlo Zancanaro@*
37 Copyright @copyright{} 2017 Thomas Danckaert
39 Permission is granted to copy, distribute and/or modify this document
40 under the terms of the GNU Free Documentation License, Version 1.3 or
41 any later version published by the Free Software Foundation; with no
42 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
43 copy of the license is included in the section entitled ``GNU Free
44 Documentation License''.
47 @dircategory System administration
49 * Guix: (guix). Manage installed software and system configuration.
50 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
51 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
52 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
53 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
56 @dircategory Software development
58 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
59 * guix build: (guix)Invoking guix build. Building packages.
60 * guix pack: (guix)Invoking guix pack. Creating binary bundles.
64 @title GNU Guix Reference Manual
65 @subtitle Using the GNU Guix Functional Package Manager
66 @author The GNU Guix Developers
69 @vskip 0pt plus 1filll
70 Edition @value{EDITION} @*
78 @c *********************************************************************
82 This document describes GNU Guix version @value{VERSION}, a functional
83 package management tool written for the GNU system.
86 * Introduction:: What is Guix about?
87 * Installation:: Installing Guix.
88 * Package Management:: Package installation, upgrade, etc.
89 * Programming Interface:: Using Guix in Scheme.
90 * Utilities:: Package management commands.
91 * GNU Distribution:: Software for your friendly GNU system.
92 * Contributing:: Your help needed!
94 * Acknowledgments:: Thanks!
95 * GNU Free Documentation License:: The license of this manual.
96 * Concept Index:: Concepts.
97 * Programming Index:: Data types, functions, and variables.
100 --- The Detailed Node Listing ---
104 * Binary Installation:: Getting Guix running in no time!
105 * Requirements:: Software needed to build and run Guix.
106 * Running the Test Suite:: Testing Guix.
107 * Setting Up the Daemon:: Preparing the build daemon's environment.
108 * Invoking guix-daemon:: Running the build daemon.
109 * Application Setup:: Application-specific setup.
111 Setting Up the Daemon
113 * Build Environment Setup:: Preparing the isolated build environment.
114 * Daemon Offload Setup:: Offloading builds to remote machines.
118 * Features:: How Guix will make your life brighter.
119 * Invoking guix package:: Package installation, removal, etc.
120 * Substitutes:: Downloading pre-built binaries.
121 * Packages with Multiple Outputs:: Single source package, multiple outputs.
122 * Invoking guix gc:: Running the garbage collector.
123 * Invoking guix pull:: Fetching the latest Guix and distribution.
124 * Invoking guix pack:: Creating software bundles.
125 * Invoking guix archive:: Exporting and importing store files.
127 Programming Interface
129 * Defining Packages:: Defining new packages.
130 * Build Systems:: Specifying how packages are built.
131 * The Store:: Manipulating the package store.
132 * Derivations:: Low-level interface to package derivations.
133 * The Store Monad:: Purely functional interface to the store.
134 * G-Expressions:: Manipulating build expressions.
138 * package Reference:: The package data type.
139 * origin Reference:: The origin data type.
143 * Invoking guix build:: Building packages from the command line.
144 * Invoking guix edit:: Editing package definitions.
145 * Invoking guix download:: Downloading a file and printing its hash.
146 * Invoking guix hash:: Computing the cryptographic hash of a file.
147 * Invoking guix import:: Importing package definitions.
148 * Invoking guix refresh:: Updating package definitions.
149 * Invoking guix lint:: Finding errors in package definitions.
150 * Invoking guix size:: Profiling disk usage.
151 * Invoking guix graph:: Visualizing the graph of packages.
152 * Invoking guix environment:: Setting up development environments.
153 * Invoking guix publish:: Sharing substitutes.
154 * Invoking guix challenge:: Challenging substitute servers.
155 * Invoking guix copy:: Copying to and from a remote store.
156 * Invoking guix container:: Process isolation.
158 Invoking @command{guix build}
160 * Common Build Options:: Build options for most commands.
161 * Package Transformation Options:: Creating variants of packages.
162 * Additional Build Options:: Options specific to 'guix build'.
166 * System Installation:: Installing the whole operating system.
167 * System Configuration:: Configuring the operating system.
168 * Documentation:: Browsing software user manuals.
169 * Installing Debugging Files:: Feeding the debugger.
170 * Security Updates:: Deploying security fixes quickly.
171 * Package Modules:: Packages from the programmer's viewpoint.
172 * Packaging Guidelines:: Growing the distribution.
173 * Bootstrapping:: GNU/Linux built from scratch.
174 * Porting:: Targeting another platform or kernel.
178 * Limitations:: What you can expect.
179 * Hardware Considerations:: Supported hardware.
180 * USB Stick Installation:: Preparing the installation medium.
181 * Preparing for Installation:: Networking, partitioning, etc.
182 * Proceeding with the Installation:: The real thing.
183 * Installing GuixSD in a VM:: GuixSD playground.
184 * Building the Installation Image:: How this comes to be.
188 * Using the Configuration System:: Customizing your GNU system.
189 * operating-system Reference:: Detail of operating-system declarations.
190 * File Systems:: Configuring file system mounts.
191 * Mapped Devices:: Block device extra processing.
192 * User Accounts:: Specifying user accounts.
193 * Locales:: Language and cultural convention settings.
194 * Services:: Specifying system services.
195 * Setuid Programs:: Programs running with root privileges.
196 * X.509 Certificates:: Authenticating HTTPS servers.
197 * Name Service Switch:: Configuring libc's name service switch.
198 * Initial RAM Disk:: Linux-Libre bootstrapping.
199 * GRUB Configuration:: Configuring the boot loader.
200 * Invoking guix system:: Instantiating a system configuration.
201 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
202 * Defining Services:: Adding new service definitions.
206 * Base Services:: Essential system services.
207 * Scheduled Job Execution:: The mcron service.
208 * Log Rotation:: The rottlog service.
209 * Networking Services:: Network setup, SSH daemon, etc.
210 * X Window:: Graphical display.
211 * Printing Services:: Local and remote printer support.
212 * Desktop Services:: D-Bus and desktop services.
213 * Database Services:: SQL databases.
214 * Mail Services:: IMAP, POP3, SMTP, and all that.
215 * Messaging Services:: Messaging services.
216 * Kerberos Services:: Kerberos services.
217 * Web Services:: Web servers.
218 * VPN Services:: VPN daemons.
219 * Network File System:: NFS related services.
220 * Continuous Integration:: The Cuirass service.
221 * Power management Services:: The TLP tool.
222 * Miscellaneous Services:: Other services.
226 * Service Composition:: The model for composing services.
227 * Service Types and Services:: Types and services.
228 * Service Reference:: API reference.
229 * Shepherd Services:: A particular type of service.
233 * Software Freedom:: What may go into the distribution.
234 * Package Naming:: What's in a name?
235 * Version Numbers:: When the name is not enough.
236 * Synopses and Descriptions:: Helping users find the right package.
237 * Python Modules:: A touch of British comedy.
238 * Perl Modules:: Little pearls.
239 * Java Packages:: Coffee break.
240 * Fonts:: Fond of fonts.
244 * Building from Git:: The latest and greatest.
245 * Running Guix Before It Is Installed:: Hacker tricks.
246 * The Perfect Setup:: The right tools.
247 * Coding Style:: Hygiene of the contributor.
248 * Submitting Patches:: Share your work.
252 * Programming Paradigm:: How to compose your elements.
253 * Modules:: Where to store your code?
254 * Data Types and Pattern Matching:: Implementing data structures.
255 * Formatting Code:: Writing conventions.
260 @c *********************************************************************
262 @chapter Introduction
265 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
266 using the international phonetic alphabet (IPA).} is a package
267 management tool for the GNU system. Guix makes it easy for unprivileged
268 users to install, upgrade, or remove packages, to roll back to a
269 previous package set, to build packages from source, and generally
270 assists with the creation and maintenance of software environments.
272 @cindex user interfaces
273 Guix provides a command-line package management interface
274 (@pxref{Invoking guix package}), a set of command-line utilities
275 (@pxref{Utilities}), as well as Scheme programming interfaces
276 (@pxref{Programming Interface}).
278 Its @dfn{build daemon} is responsible for building packages on behalf of
279 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
280 binaries from authorized sources (@pxref{Substitutes}).
282 @cindex extensibility of the distribution
283 @cindex customization, of packages
284 Guix includes package definitions for many GNU and non-GNU packages, all
285 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
286 user's computing freedom}. It is @emph{extensible}: users can write
287 their own package definitions (@pxref{Defining Packages}) and make them
288 available as independent package modules (@pxref{Package Modules}). It
289 is also @emph{customizable}: users can @emph{derive} specialized package
290 definitions from existing ones, including from the command line
291 (@pxref{Package Transformation Options}).
293 @cindex Guix System Distribution
295 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
296 where it complements the available tools without interference
297 (@pxref{Installation}), or you can use it as part of the standalone
298 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
299 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
300 system configuration and Guix takes care of instantiating the
301 configuration in a transactional, reproducible, and stateless fashion
302 (@pxref{System Configuration}).
304 @cindex functional package management
305 Under the hood, Guix implements the @dfn{functional package management}
306 discipline pioneered by Nix (@pxref{Acknowledgments}).
307 In Guix, the package build and installation process is seen
308 as a @emph{function}, in the mathematical sense. That function takes inputs,
309 such as build scripts, a compiler, and libraries, and
310 returns an installed package. As a pure function, its result depends
311 solely on its inputs---for instance, it cannot refer to software or
312 scripts that were not explicitly passed as inputs. A build function
313 always produces the same result when passed a given set of inputs. It
314 cannot alter the environment of the running system in
315 any way; for instance, it cannot create, modify, or delete files outside
316 of its build and installation directories. This is achieved by running
317 build processes in isolated environments (or @dfn{containers}), where only their
318 explicit inputs are visible.
321 The result of package build functions is @dfn{cached} in the file
322 system, in a special directory called @dfn{the store} (@pxref{The
323 Store}). Each package is installed in a directory of its own in the
324 store---by default under @file{/gnu/store}. The directory name contains
325 a hash of all the inputs used to build that package; thus, changing an
326 input yields a different directory name.
328 This approach is the foundation for the salient features of Guix: support
329 for transactional package upgrade and rollback, per-user installation, and
330 garbage collection of packages (@pxref{Features}).
333 @c *********************************************************************
335 @chapter Installation
337 @cindex installing Guix
338 GNU Guix is available for download from its website at
339 @url{http://www.gnu.org/software/guix/}. This section describes the
340 software requirements of Guix, as well as how to install it and get
343 Note that this section is concerned with the installation of the package
344 manager, which can be done on top of a running GNU/Linux system. If,
345 instead, you want to install the complete GNU operating system,
346 @pxref{System Installation}.
348 @cindex foreign distro
349 When installed on a running GNU/Linux system---thereafter called a
350 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
351 without interference. Its data lives exclusively in two directories,
352 usually @file{/gnu/store} and @file{/var/guix}; other files on your
353 system, such as @file{/etc}, are left untouched.
355 Once installed, Guix can be updated by running @command{guix pull}
356 (@pxref{Invoking guix pull}).
359 * Binary Installation:: Getting Guix running in no time!
360 * Requirements:: Software needed to build and run Guix.
361 * Running the Test Suite:: Testing Guix.
362 * Setting Up the Daemon:: Preparing the build daemon's environment.
363 * Invoking guix-daemon:: Running the build daemon.
364 * Application Setup:: Application-specific setup.
367 @node Binary Installation
368 @section Binary Installation
370 @cindex installing Guix from binaries
371 This section describes how to install Guix on an arbitrary system from a
372 self-contained tarball providing binaries for Guix and for all its
373 dependencies. This is often quicker than installing from source, which
374 is described in the next sections. The only requirement is to have
377 Installing goes along these lines:
381 @cindex downloading Guix binary
382 Download the binary tarball from
383 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
384 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
385 already running the kernel Linux, and so on.
387 @c The following is somewhat duplicated in ``System Installation''.
388 Make sure to download the associated @file{.sig} file and to verify the
389 authenticity of the tarball against it, along these lines:
392 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
393 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
396 If that command fails because you do not have the required public key,
397 then run this command to import it:
400 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
404 and rerun the @code{gpg --verify} command.
405 @c end authentication part
412 # tar --warning=no-timestamp -xf \
413 guix-binary-@value{VERSION}.@var{system}.tar.xz
414 # mv var/guix /var/ && mv gnu /
417 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
418 The latter contains a ready-to-use profile for @code{root} (see next
421 Do @emph{not} unpack the tarball on a working Guix system since that
422 would overwrite its own essential files.
424 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
425 not emit warnings about ``implausibly old time stamps'' (such
426 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
428 They stem from the fact that all the
429 files in the archive have their modification time set to zero (which
430 means January 1st, 1970.) This is done on purpose to make sure the
431 archive content is independent of its creation time, thus making it
435 Make @code{root}'s profile available under @file{~/.guix-profile}:
438 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
442 Source @file{etc/profile} to augment @code{PATH} and other relevant
443 environment variables:
446 # GUIX_PROFILE=$HOME/.guix-profile \
447 source $GUIX_PROFILE/etc/profile
451 Create the group and user accounts for build users as explained below
452 (@pxref{Build Environment Setup}).
455 Run the daemon, and set it to automatically start on boot.
457 If your host distro uses the systemd init system, this can be achieved
460 @c Versions of systemd that supported symlinked service files are not
461 @c yet widely deployed, so we should suggest that users copy the service
464 @c See this thread for more information:
465 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
468 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
470 # systemctl start guix-daemon && systemctl enable guix-daemon
473 If your host distro uses the Upstart init system:
476 # initctl reload-configuration
477 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
481 Otherwise, you can still start the daemon manually with:
484 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
488 Make the @command{guix} command available to other users on the machine,
492 # mkdir -p /usr/local/bin
494 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
497 It is also a good idea to make the Info version of this manual available
501 # mkdir -p /usr/local/share/info
502 # cd /usr/local/share/info
503 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
507 That way, assuming @file{/usr/local/share/info} is in the search path,
508 running @command{info guix} will open this manual (@pxref{Other Info
509 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
513 @cindex substitutes, authorization thereof
514 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
515 (@pxref{Substitutes}), authorize them:
518 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
522 Each user may need to perform a few additional steps to make their Guix
523 environment ready for use, @pxref{Application Setup}.
526 Voilà, the installation is complete!
528 You can confirm that Guix is working by installing a sample package into
532 # guix package -i hello
535 The @code{guix} package must remain available in @code{root}'s profile,
536 or it would become subject to garbage collection---in which case you
537 would find yourself badly handicapped by the lack of the @command{guix}
538 command. In other words, do not remove @code{guix} by running
539 @code{guix package -r guix}.
541 The binary installation tarball can be (re)produced and verified simply
542 by running the following command in the Guix source tree:
545 make guix-binary.@var{system}.tar.xz
549 ... which, in turn, runs:
552 guix pack -s @var{system} --localstatedir guix
555 @xref{Invoking guix pack}, for more info on this handy tool.
558 @section Requirements
560 This section lists requirements when building Guix from source. The
561 build procedure for Guix is the same as for other GNU software, and is
562 not covered here. Please see the files @file{README} and @file{INSTALL}
563 in the Guix source tree for additional details.
565 GNU Guix depends on the following packages:
568 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
569 later, including 2.2.x;
570 @item @url{http://gnupg.org/, GNU libgcrypt};
572 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
573 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
574 Guile,, gnutls-guile, GnuTLS-Guile});
575 @item @url{http://www.gnu.org/software/make/, GNU Make}.
578 The following dependencies are optional:
583 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
584 allow you to use the @command{guix import pypi} command (@pxref{Invoking
585 guix import}). It is of
586 interest primarily for developers and not for casual users.
589 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
590 Support for build offloading (@pxref{Daemon Offload Setup}) and
591 @command{guix copy} (@pxref{Invoking guix copy}) depends on
592 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
593 version 0.10.2 or later.
596 When @url{http://zlib.net, zlib} is available, @command{guix publish}
597 can compress build byproducts (@pxref{Invoking guix publish}).
600 Unless @code{--disable-daemon} was passed to @command{configure}, the
601 following packages are also needed:
604 @item @url{http://sqlite.org, SQLite 3};
605 @item @url{http://www.bzip.org, libbz2};
606 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
610 @cindex state directory
611 When configuring Guix on a system that already has a Guix installation,
612 be sure to specify the same state directory as the existing installation
613 using the @code{--localstatedir} option of the @command{configure}
614 script (@pxref{Directory Variables, @code{localstatedir},, standards,
615 GNU Coding Standards}). The @command{configure} script protects against
616 unintended misconfiguration of @var{localstatedir} so you do not
617 inadvertently corrupt your store (@pxref{The Store}).
619 @cindex Nix, compatibility
620 When a working installation of @url{http://nixos.org/nix/, the Nix package
621 manager} is available, you
622 can instead configure Guix with @code{--disable-daemon}. In that case,
623 Nix replaces the three dependencies above.
625 Guix is compatible with Nix, so it is possible to share the same store
626 between both. To do so, you must pass @command{configure} not only the
627 same @code{--with-store-dir} value, but also the same
628 @code{--localstatedir} value. The latter is essential because it
629 specifies where the database that stores metadata about the store is
630 located, among other things. The default values for Nix are
631 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
632 Note that @code{--disable-daemon} is not required if
633 your goal is to share the store with Nix.
635 @node Running the Test Suite
636 @section Running the Test Suite
639 After a successful @command{configure} and @code{make} run, it is a good
640 idea to run the test suite. It can help catch issues with the setup or
641 environment, or bugs in Guix itself---and really, reporting test
642 failures is a good way to help improve the software. To run the test
649 Test cases can run in parallel: you can use the @code{-j} option of
650 GNU@tie{}make to speed things up. The first run may take a few minutes
651 on a recent machine; subsequent runs will be faster because the store
652 that is created for test purposes will already have various things in
655 It is also possible to run a subset of the tests by defining the
656 @code{TESTS} makefile variable as in this example:
659 make check TESTS="tests/store.scm tests/cpio.scm"
662 By default, tests results are displayed at a file level. In order to
663 see the details of every individual test cases, it is possible to define
664 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
667 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
670 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
671 @file{test-suite.log} file. Please specify the Guix version being used
672 as well as version numbers of the dependencies (@pxref{Requirements}) in
675 Guix also comes with a whole-system test suite that tests complete
676 GuixSD operating system instances. It can only run on systems where
677 Guix is already installed, using:
684 or, again, by defining @code{TESTS} to select a subset of tests to run:
687 make check-system TESTS="basic mcron"
690 These system tests are defined in the @code{(gnu tests @dots{})}
691 modules. They work by running the operating systems under test with
692 lightweight instrumentation in a virtual machine (VM). They can be
693 computationally intensive or rather cheap, depending on whether
694 substitutes are available for their dependencies (@pxref{Substitutes}).
695 Some of them require a lot of storage space to hold VM images.
697 Again in case of test failures, please send @email{bug-guix@@gnu.org}
700 @node Setting Up the Daemon
701 @section Setting Up the Daemon
704 Operations such as building a package or running the garbage collector
705 are all performed by a specialized process, the @dfn{build daemon}, on
706 behalf of clients. Only the daemon may access the store and its
707 associated database. Thus, any operation that manipulates the store
708 goes through the daemon. For instance, command-line tools such as
709 @command{guix package} and @command{guix build} communicate with the
710 daemon (@i{via} remote procedure calls) to instruct it what to do.
712 The following sections explain how to prepare the build daemon's
713 environment. See also @ref{Substitutes}, for information on how to allow
714 the daemon to download pre-built binaries.
717 * Build Environment Setup:: Preparing the isolated build environment.
718 * Daemon Offload Setup:: Offloading builds to remote machines.
721 @node Build Environment Setup
722 @subsection Build Environment Setup
724 @cindex build environment
725 In a standard multi-user setup, Guix and its daemon---the
726 @command{guix-daemon} program---are installed by the system
727 administrator; @file{/gnu/store} is owned by @code{root} and
728 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
729 Guix tools to build packages or otherwise access the store, and the
730 daemon will do it on their behalf, ensuring that the store is kept in a
731 consistent state, and allowing built packages to be shared among users.
734 When @command{guix-daemon} runs as @code{root}, you may not want package
735 build processes themselves to run as @code{root} too, for obvious
736 security reasons. To avoid that, a special pool of @dfn{build users}
737 should be created for use by build processes started by the daemon.
738 These build users need not have a shell and a home directory: they will
739 just be used when the daemon drops @code{root} privileges in build
740 processes. Having several such users allows the daemon to launch
741 distinct build processes under separate UIDs, which guarantees that they
742 do not interfere with each other---an essential feature since builds are
743 regarded as pure functions (@pxref{Introduction}).
745 On a GNU/Linux system, a build user pool may be created like this (using
746 Bash syntax and the @code{shadow} commands):
748 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
749 @c for why `-G' is needed.
751 # groupadd --system guixbuild
752 # for i in `seq -w 1 10`;
754 useradd -g guixbuild -G guixbuild \
755 -d /var/empty -s `which nologin` \
756 -c "Guix build user $i" --system \
762 The number of build users determines how many build jobs may run in
763 parallel, as specified by the @option{--max-jobs} option
764 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
765 @command{guix system vm} and related commands, you may need to add the
766 build users to the @code{kvm} group so they can access @file{/dev/kvm},
767 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
768 (@pxref{Invoking guix system}).
770 The @code{guix-daemon} program may then be run as @code{root} with the
771 following command@footnote{If your machine uses the systemd init system,
772 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
773 file in @file{/etc/systemd/system} will ensure that
774 @command{guix-daemon} is automatically started. Similarly, if your
775 machine uses the Upstart init system, drop the
776 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
777 file in @file{/etc/init}.}:
780 # guix-daemon --build-users-group=guixbuild
785 This way, the daemon starts build processes in a chroot, under one of
786 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
787 environment contains nothing but:
789 @c Keep this list in sync with libstore/build.cc! -----------------------
792 a minimal @code{/dev} directory, created mostly independently from the
793 host @code{/dev}@footnote{``Mostly'', because while the set of files
794 that appear in the chroot's @code{/dev} is fixed, most of these files
795 can only be created if the host has them.};
798 the @code{/proc} directory; it only shows the processes of the container
799 since a separate PID name space is used;
802 @file{/etc/passwd} with an entry for the current user and an entry for
806 @file{/etc/group} with an entry for the user's group;
809 @file{/etc/hosts} with an entry that maps @code{localhost} to
813 a writable @file{/tmp} directory.
816 You can influence the directory where the daemon stores build trees
817 @i{via} the @code{TMPDIR} environment variable. However, the build tree
818 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
819 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
820 This way, the value of @code{TMPDIR} does not leak inside build
821 environments, which avoids discrepancies in cases where build processes
822 capture the name of their build tree.
825 The daemon also honors the @code{http_proxy} environment variable for
826 HTTP downloads it performs, be it for fixed-output derivations
827 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
829 If you are installing Guix as an unprivileged user, it is still possible
830 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
831 However, build processes will not be isolated from one another, and not
832 from the rest of the system. Thus, build processes may interfere with
833 each other, and may access programs, libraries, and other files
834 available on the system---making it much harder to view them as
835 @emph{pure} functions.
838 @node Daemon Offload Setup
839 @subsection Using the Offload Facility
843 When desired, the build daemon can @dfn{offload} derivation builds to
844 other machines running Guix, using the @code{offload} @dfn{build
845 hook}@footnote{This feature is available only when
846 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
848 feature is enabled, a list of user-specified build machines is read from
849 @file{/etc/guix/machines.scm}; every time a build is requested, for
850 instance via @code{guix build}, the daemon attempts to offload it to one
851 of the machines that satisfy the constraints of the derivation, in
852 particular its system type---e.g., @file{x86_64-linux}. Missing
853 prerequisites for the build are copied over SSH to the target machine,
854 which then proceeds with the build; upon success the output(s) of the
855 build are copied back to the initial machine.
857 The @file{/etc/guix/machines.scm} file typically looks like this:
861 (name "eightysix.example.org")
862 (system "x86_64-linux")
863 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
865 (speed 2.)) ;incredibly fast!
868 (name "meeps.example.org")
869 (system "mips64el-linux")
870 (host-key "ssh-rsa AAAAB3Nza@dots{}")
873 (string-append (getenv "HOME")
874 "/.ssh/identity-for-guix"))))
878 In the example above we specify a list of two build machines, one for
879 the @code{x86_64} architecture and one for the @code{mips64el}
882 In fact, this file is---not surprisingly!---a Scheme file that is
883 evaluated when the @code{offload} hook is started. Its return value
884 must be a list of @code{build-machine} objects. While this example
885 shows a fixed list of build machines, one could imagine, say, using
886 DNS-SD to return a list of potential build machines discovered in the
887 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
888 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
891 @deftp {Data Type} build-machine
892 This data type represents build machines to which the daemon may offload
893 builds. The important fields are:
898 The host name of the remote machine.
901 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
904 The user account to use when connecting to the remote machine over SSH.
905 Note that the SSH key pair must @emph{not} be passphrase-protected, to
906 allow non-interactive logins.
909 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
910 This is used to authenticate the machine when we connect to it. It is a
911 long string that looks like this:
914 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
917 If the machine is running the OpenSSH daemon, @command{sshd}, the host
918 key can be found in a file such as
919 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
921 If the machine is running the SSH daemon of GNU@tie{}lsh,
922 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
923 similar file. It can be converted to the OpenSSH format using
924 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
927 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
928 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
933 A number of optional fields may be specified:
937 @item @code{port} (default: @code{22})
938 Port number of SSH server on the machine.
940 @item @code{private-key} (default: @file{~/.ssh/id_rsa})
941 The SSH private key file to use when connecting to the machine, in
944 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
945 @itemx @code{compression-level} (default: @code{3})
946 The SSH-level compression methods and compression level requested.
948 Note that offloading relies on SSH compression to reduce bandwidth usage
949 when transferring files to and from build machines.
951 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
952 File name of the Unix-domain socket @command{guix-daemon} is listening
955 @item @code{parallel-builds} (default: @code{1})
956 The number of builds that may run in parallel on the machine.
958 @item @code{speed} (default: @code{1.0})
959 A ``relative speed factor''. The offload scheduler will tend to prefer
960 machines with a higher speed factor.
962 @item @code{features} (default: @code{'()})
963 A list of strings denoting specific features supported by the machine.
964 An example is @code{"kvm"} for machines that have the KVM Linux modules
965 and corresponding hardware support. Derivations can request features by
966 name, and they will be scheduled on matching build machines.
971 The @code{guile} command must be in the search path on the build
972 machines. In addition, the Guix modules must be in
973 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
974 this is the case by running:
977 ssh build-machine guile -c "'(use-modules (guix config))'"
980 There is one last thing to do once @file{machines.scm} is in place. As
981 explained above, when offloading, files are transferred back and forth
982 between the machine stores. For this to work, you first need to
983 generate a key pair on each machine to allow the daemon to export signed
984 archives of files from the store (@pxref{Invoking guix archive}):
987 # guix archive --generate-key
991 Each build machine must authorize the key of the master machine so that
992 it accepts store items it receives from the master:
995 # guix archive --authorize < master-public-key.txt
999 Likewise, the master machine must authorize the key of each build machine.
1001 All the fuss with keys is here to express pairwise mutual trust
1002 relations between the master and the build machines. Concretely, when
1003 the master receives files from a build machine (and @i{vice versa}), its
1004 build daemon can make sure they are genuine, have not been tampered
1005 with, and that they are signed by an authorized key.
1007 @cindex offload test
1008 To test whether your setup is operational, run this command on the
1015 This will attempt to connect to each of the build machines specified in
1016 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1017 available on each machine, attempt to export to the machine and import
1018 from it, and report any error in the process.
1020 If you want to test a different machine file, just specify it on the
1024 # guix offload test machines-qualif.scm
1027 Last, you can test the subset of the machines whose name matches a
1028 regular expression like this:
1031 # guix offload test machines.scm '\.gnu\.org$'
1034 @node Invoking guix-daemon
1035 @section Invoking @command{guix-daemon}
1037 The @command{guix-daemon} program implements all the functionality to
1038 access the store. This includes launching build processes, running the
1039 garbage collector, querying the availability of a build result, etc. It
1040 is normally run as @code{root} like this:
1043 # guix-daemon --build-users-group=guixbuild
1047 For details on how to set it up, @pxref{Setting Up the Daemon}.
1050 @cindex container, build environment
1051 @cindex build environment
1052 @cindex reproducible builds
1053 By default, @command{guix-daemon} launches build processes under
1054 different UIDs, taken from the build group specified with
1055 @code{--build-users-group}. In addition, each build process is run in a
1056 chroot environment that only contains the subset of the store that the
1057 build process depends on, as specified by its derivation
1058 (@pxref{Programming Interface, derivation}), plus a set of specific
1059 system directories. By default, the latter contains @file{/dev} and
1060 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1061 @dfn{container}: in addition to having its own file system tree, it has
1062 a separate mount name space, its own PID name space, network name space,
1063 etc. This helps achieve reproducible builds (@pxref{Features}).
1065 When the daemon performs a build on behalf of the user, it creates a
1066 build directory under @file{/tmp} or under the directory specified by
1067 its @code{TMPDIR} environment variable; this directory is shared with
1068 the container for the duration of the build. Be aware that using a
1069 directory other than @file{/tmp} can affect build results---for example,
1070 with a longer directory name, a build process that uses Unix-domain
1071 sockets might hit the name length limitation for @code{sun_path}, which
1072 it would otherwise not hit.
1074 The build directory is automatically deleted upon completion, unless the
1075 build failed and the client specified @option{--keep-failed}
1076 (@pxref{Invoking guix build, @option{--keep-failed}}).
1078 The following command-line options are supported:
1081 @item --build-users-group=@var{group}
1082 Take users from @var{group} to run build processes (@pxref{Setting Up
1083 the Daemon, build users}).
1085 @item --no-substitutes
1087 Do not use substitutes for build products. That is, always build things
1088 locally instead of allowing downloads of pre-built binaries
1089 (@pxref{Substitutes}).
1091 By default substitutes are used, unless the client---such as the
1092 @command{guix package} command---is explicitly invoked with
1093 @code{--no-substitutes}.
1095 When the daemon runs with @code{--no-substitutes}, clients can still
1096 explicitly enable substitution @i{via} the @code{set-build-options}
1097 remote procedure call (@pxref{The Store}).
1099 @item --substitute-urls=@var{urls}
1100 @anchor{daemon-substitute-urls}
1101 Consider @var{urls} the default whitespace-separated list of substitute
1102 source URLs. When this option is omitted,
1103 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1104 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1106 This means that substitutes may be downloaded from @var{urls}, as long
1107 as they are signed by a trusted signature (@pxref{Substitutes}).
1110 @item --no-build-hook
1111 Do not use the @dfn{build hook}.
1113 The build hook is a helper program that the daemon can start and to
1114 which it submits build requests. This mechanism is used to offload
1115 builds to other machines (@pxref{Daemon Offload Setup}).
1117 @item --cache-failures
1118 Cache build failures. By default, only successful builds are cached.
1120 When this option is used, @command{guix gc --list-failures} can be used
1121 to query the set of store items marked as failed; @command{guix gc
1122 --clear-failures} removes store items from the set of cached failures.
1123 @xref{Invoking guix gc}.
1125 @item --cores=@var{n}
1127 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1130 The default value is @code{0}, but it may be overridden by clients, such
1131 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1134 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1135 in the build process, which can then use it to exploit internal
1136 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1138 @item --max-jobs=@var{n}
1140 Allow at most @var{n} build jobs in parallel. The default value is
1141 @code{1}. Setting it to @code{0} means that no builds will be performed
1142 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1143 Setup}), or simply fail.
1145 @item --rounds=@var{N}
1146 Build each derivation @var{n} times in a row, and raise an error if
1147 consecutive build results are not bit-for-bit identical. Note that this
1148 setting can be overridden by clients such as @command{guix build}
1149 (@pxref{Invoking guix build}).
1151 When used in conjunction with @option{--keep-failed}, the differing
1152 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1153 This makes it easy to look for differences between the two results.
1156 Produce debugging output.
1158 This is useful to debug daemon start-up issues, but then it may be
1159 overridden by clients, for example the @code{--verbosity} option of
1160 @command{guix build} (@pxref{Invoking guix build}).
1162 @item --chroot-directory=@var{dir}
1163 Add @var{dir} to the build chroot.
1165 Doing this may change the result of build processes---for instance if
1166 they use optional dependencies found in @var{dir} when it is available,
1167 and not otherwise. For that reason, it is not recommended to do so.
1168 Instead, make sure that each derivation declares all the inputs that it
1171 @item --disable-chroot
1172 Disable chroot builds.
1174 Using this option is not recommended since, again, it would allow build
1175 processes to gain access to undeclared dependencies. It is necessary,
1176 though, when @command{guix-daemon} is running under an unprivileged user
1179 @item --disable-log-compression
1180 Disable compression of the build logs.
1182 Unless @code{--lose-logs} is used, all the build logs are kept in the
1183 @var{localstatedir}. To save space, the daemon automatically compresses
1184 them with bzip2 by default. This option disables that.
1186 @item --disable-deduplication
1187 @cindex deduplication
1188 Disable automatic file ``deduplication'' in the store.
1190 By default, files added to the store are automatically ``deduplicated'':
1191 if a newly added file is identical to another one found in the store,
1192 the daemon makes the new file a hard link to the other file. This can
1193 noticeably reduce disk usage, at the expense of slightly increased
1194 input/output load at the end of a build process. This option disables
1197 @item --gc-keep-outputs[=yes|no]
1198 Tell whether the garbage collector (GC) must keep outputs of live
1201 When set to ``yes'', the GC will keep the outputs of any live derivation
1202 available in the store---the @code{.drv} files. The default is ``no'',
1203 meaning that derivation outputs are kept only if they are GC roots.
1205 @item --gc-keep-derivations[=yes|no]
1206 Tell whether the garbage collector (GC) must keep derivations
1207 corresponding to live outputs.
1209 When set to ``yes'', as is the case by default, the GC keeps
1210 derivations---i.e., @code{.drv} files---as long as at least one of their
1211 outputs is live. This allows users to keep track of the origins of
1212 items in their store. Setting it to ``no'' saves a bit of disk space.
1214 Note that when both @code{--gc-keep-derivations} and
1215 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1216 prerequisites (the sources, compiler, libraries, and other build-time
1217 tools) of live objects in the store, regardless of whether these
1218 prerequisites are live. This is convenient for developers since it
1219 saves rebuilds or downloads.
1221 @item --impersonate-linux-2.6
1222 On Linux-based systems, impersonate Linux 2.6. This means that the
1223 kernel's @code{uname} system call will report 2.6 as the release number.
1225 This might be helpful to build programs that (usually wrongfully) depend
1226 on the kernel version number.
1229 Do not keep build logs. By default they are kept under
1230 @code{@var{localstatedir}/guix/log}.
1232 @item --system=@var{system}
1233 Assume @var{system} as the current system type. By default it is the
1234 architecture/kernel pair found at configure time, such as
1235 @code{x86_64-linux}.
1237 @item --listen=@var{socket}
1238 Listen for connections on @var{socket}, the file name of a Unix-domain
1239 socket. The default socket is
1240 @file{@var{localstatedir}/daemon-socket/socket}. This option is only
1241 useful in exceptional circumstances, such as if you need to run several
1242 daemons on the same machine.
1246 @node Application Setup
1247 @section Application Setup
1249 @cindex foreign distro
1250 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1251 so-called @dfn{foreign distro}---a few additional steps are needed to
1252 get everything in place. Here are some of them.
1256 @anchor{locales-and-locpath}
1257 @cindex locales, when not on GuixSD
1259 @vindex GUIX_LOCPATH
1260 Packages installed @i{via} Guix will not use the locale data of the
1261 host system. Instead, you must first install one of the locale packages
1262 available with Guix and then define the @code{GUIX_LOCPATH} environment
1266 $ guix package -i glibc-locales
1267 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1270 Note that the @code{glibc-locales} package contains data for all the
1271 locales supported by the GNU@tie{}libc and weighs in at around
1272 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1273 limited to a few UTF-8 locales.
1275 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1276 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1277 Manual}). There are two important differences though:
1281 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1282 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1283 to make sure the programs of the foreign distro will not end up loading
1284 incompatible locale data.
1287 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1288 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1289 should your Guix profile contain a mixture of programs linked against
1290 different libc version, each libc version will only try to load locale
1291 data in the right format.
1294 This is important because the locale data format used by different libc
1295 versions may be incompatible.
1297 @subsection Name Service Switch
1299 @cindex name service switch, glibc
1300 @cindex NSS (name service switch), glibc
1301 @cindex nscd (name service caching daemon)
1302 @cindex name service caching daemon (nscd)
1303 When using Guix on a foreign distro, we @emph{strongly recommend} that
1304 the system run the GNU C library's @dfn{name service cache daemon},
1305 @command{nscd}, which should be listening on the
1306 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1307 installed with Guix may fail to look up host names or user accounts, or
1308 may even crash. The next paragraphs explain why.
1310 @cindex @file{nsswitch.conf}
1311 The GNU C library implements a @dfn{name service switch} (NSS), which is
1312 an extensible mechanism for ``name lookups'' in general: host name
1313 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1314 The GNU C Library Reference Manual}).
1316 @cindex Network information service (NIS)
1317 @cindex NIS (Network information service)
1318 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1319 lookup implementations: for example, the @code{nss-mdns} plugin allow
1320 resolution of @code{.local} host names, the @code{nis} plugin allows
1321 user account lookup using the Network information service (NIS), and so
1322 on. These extra ``lookup services'' are configured system-wide in
1323 @file{/etc/nsswitch.conf}, and all the programs running on the system
1324 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1327 When they perform a name lookup---for instance by calling the
1328 @code{getaddrinfo} function in C---applications first try to connect to
1329 the nscd; on success, nscd performs name lookups on their behalf. If
1330 the nscd is not running, then they perform the name lookup by
1331 themselves, by loading the name lookup services into their own address
1332 space and running it. These name lookup services---the
1333 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1334 the host system's C library, rather than from the C library the
1335 application is linked against (the C library coming from Guix).
1337 And this is where the problem is: if your application is linked against
1338 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1339 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1340 likely crash or have its name lookups fail unexpectedly.
1342 Running @command{nscd} on the system, among other advantages, eliminates
1343 this binary incompatibility problem because those @code{libnss_*.so}
1344 files are loaded in the @command{nscd} process, not in applications
1347 @subsection X11 Fonts
1350 The majority of graphical applications use Fontconfig to locate and
1351 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1352 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1353 by default. Thus, to allow graphical applications installed with Guix
1354 to display fonts, you have to install fonts with Guix as well.
1355 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1356 @code{font-gnu-freefont-ttf}.
1358 To display text written in Chinese languages, Japanese, or Korean in
1359 graphical applications, consider installing
1360 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1361 has multiple outputs, one per language family (@pxref{Packages with
1362 Multiple Outputs}). For instance, the following command installs fonts
1363 for Chinese languages:
1366 guix package -i font-adobe-source-han-sans:cn
1369 @cindex @code{xterm}
1370 Older programs such as @command{xterm} do not use Fontconfig and instead
1371 rely on server-side font rendering. Such programs require to specify a
1372 full name of a font using XLFD (X Logical Font Description), like this:
1375 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1378 To be able to use such full names for the TrueType fonts installed in
1379 your Guix profile, you need to extend the font path of the X server:
1382 xset +fp ~/.guix-profile/share/fonts/truetype
1385 @cindex @code{xlsfonts}
1386 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1387 to make sure your TrueType fonts are listed there.
1389 @subsection X.509 Certificates
1391 @cindex @code{nss-certs}
1392 The @code{nss-certs} package provides X.509 certificates, which allow
1393 programs to authenticate Web servers accessed over HTTPS.
1395 When using Guix on a foreign distro, you can install this package and
1396 define the relevant environment variables so that packages know where to
1397 look for certificates. @xref{X.509 Certificates}, for detailed
1400 @subsection Emacs Packages
1402 @cindex @code{emacs}
1403 When you install Emacs packages with Guix, the elisp files may be placed
1404 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1406 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1407 directory exists because potentially there may exist thousands of Emacs
1408 packages and storing all their files in a single directory may be not
1409 reliable (because of name conflicts). So we think using a separate
1410 directory for each package is a good idea. It is very similar to how
1411 the Emacs package system organizes the file structure (@pxref{Package
1412 Files,,, emacs, The GNU Emacs Manual}).
1414 By default, Emacs (installed with Guix) ``knows'' where these packages
1415 are placed, so you do not need to perform any configuration. If, for
1416 some reason, you want to avoid auto-loading Emacs packages installed
1417 with Guix, you can do so by running Emacs with @code{--no-site-file}
1418 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1422 @c *********************************************************************
1423 @node Package Management
1424 @chapter Package Management
1427 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1428 remove software packages, without having to know about their build
1429 procedures or dependencies. Guix also goes beyond this obvious set of
1432 This chapter describes the main features of Guix, as well as the package
1433 management tools it provides. Along with the command-line interface
1434 described below (@pxref{Invoking guix package, @code{guix package}}),
1435 you may also use Emacs Interface, after installing @code{emacs-guix}
1436 package (run @kbd{M-x guix-help} command to start with it):
1439 guix package -i emacs-guix
1443 * Features:: How Guix will make your life brighter.
1444 * Invoking guix package:: Package installation, removal, etc.
1445 * Substitutes:: Downloading pre-built binaries.
1446 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1447 * Invoking guix gc:: Running the garbage collector.
1448 * Invoking guix pull:: Fetching the latest Guix and distribution.
1449 * Invoking guix pack:: Creating software bundles.
1450 * Invoking guix archive:: Exporting and importing store files.
1456 When using Guix, each package ends up in the @dfn{package store}, in its
1457 own directory---something that resembles
1458 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1460 Instead of referring to these directories, users have their own
1461 @dfn{profile}, which points to the packages that they actually want to
1462 use. These profiles are stored within each user's home directory, at
1463 @code{$HOME/.guix-profile}.
1465 For example, @code{alice} installs GCC 4.7.2. As a result,
1466 @file{/home/alice/.guix-profile/bin/gcc} points to
1467 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1468 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1469 simply continues to point to
1470 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1471 coexist on the same system without any interference.
1473 The @command{guix package} command is the central tool to manage
1474 packages (@pxref{Invoking guix package}). It operates on the per-user
1475 profiles, and can be used @emph{with normal user privileges}.
1477 @cindex transactions
1478 The command provides the obvious install, remove, and upgrade
1479 operations. Each invocation is actually a @emph{transaction}: either
1480 the specified operation succeeds, or nothing happens. Thus, if the
1481 @command{guix package} process is terminated during the transaction,
1482 or if a power outage occurs during the transaction, then the user's
1483 profile remains in its previous state, and remains usable.
1485 In addition, any package transaction may be @emph{rolled back}. So, if,
1486 for example, an upgrade installs a new version of a package that turns
1487 out to have a serious bug, users may roll back to the previous instance
1488 of their profile, which was known to work well. Similarly, the global
1489 system configuration on GuixSD is subject to
1490 transactional upgrades and roll-back
1491 (@pxref{Using the Configuration System}).
1493 All packages in the package store may be @emph{garbage-collected}.
1494 Guix can determine which packages are still referenced by user
1495 profiles, and remove those that are provably no longer referenced
1496 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1497 generations of their profile so that the packages they refer to can be
1500 @cindex reproducibility
1501 @cindex reproducible builds
1502 Finally, Guix takes a @dfn{purely functional} approach to package
1503 management, as described in the introduction (@pxref{Introduction}).
1504 Each @file{/gnu/store} package directory name contains a hash of all the
1505 inputs that were used to build that package---compiler, libraries, build
1506 scripts, etc. This direct correspondence allows users to make sure a
1507 given package installation matches the current state of their
1508 distribution. It also helps maximize @dfn{build reproducibility}:
1509 thanks to the isolated build environments that are used, a given build
1510 is likely to yield bit-identical files when performed on different
1511 machines (@pxref{Invoking guix-daemon, container}).
1514 This foundation allows Guix to support @dfn{transparent binary/source
1515 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1516 available from an external source---a @dfn{substitute}, Guix just
1517 downloads it and unpacks it;
1518 otherwise, it builds the package from source, locally
1519 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1520 reproducible, users do not have to trust servers that provide
1521 substitutes: they can force a local build and @emph{challenge} providers
1522 (@pxref{Invoking guix challenge}).
1524 Control over the build environment is a feature that is also useful for
1525 developers. The @command{guix environment} command allows developers of
1526 a package to quickly set up the right development environment for their
1527 package, without having to manually install the dependencies of the
1528 package into their profile (@pxref{Invoking guix environment}).
1530 @node Invoking guix package
1531 @section Invoking @command{guix package}
1533 @cindex installing packages
1534 @cindex removing packages
1535 @cindex package installation
1536 @cindex package removal
1537 The @command{guix package} command is the tool that allows users to
1538 install, upgrade, and remove packages, as well as rolling back to
1539 previous configurations. It operates only on the user's own profile,
1540 and works with normal user privileges (@pxref{Features}). Its syntax
1544 guix package @var{options}
1546 @cindex transactions
1547 Primarily, @var{options} specifies the operations to be performed during
1548 the transaction. Upon completion, a new profile is created, but
1549 previous @dfn{generations} of the profile remain available, should the user
1552 For example, to remove @code{lua} and install @code{guile} and
1553 @code{guile-cairo} in a single transaction:
1556 guix package -r lua -i guile guile-cairo
1559 @command{guix package} also supports a @dfn{declarative approach}
1560 whereby the user specifies the exact set of packages to be available and
1561 passes it @i{via} the @option{--manifest} option
1562 (@pxref{profile-manifest, @option{--manifest}}).
1565 For each user, a symlink to the user's default profile is automatically
1566 created in @file{$HOME/.guix-profile}. This symlink always points to the
1567 current generation of the user's default profile. Thus, users can add
1568 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1569 variable, and so on.
1570 @cindex search paths
1571 If you are not using the Guix System Distribution, consider adding the
1572 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1573 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1574 shells get all the right environment variable definitions:
1577 GUIX_PROFILE="$HOME/.guix-profile" \
1578 source "$HOME/.guix-profile/etc/profile"
1581 In a multi-user setup, user profiles are stored in a place registered as
1582 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1583 to (@pxref{Invoking guix gc}). That directory is normally
1584 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1585 @var{localstatedir} is the value passed to @code{configure} as
1586 @code{--localstatedir}, and @var{user} is the user name. The
1587 @file{per-user} directory is created when @command{guix-daemon} is
1588 started, and the @var{user} sub-directory is created by @command{guix
1591 The @var{options} can be among the following:
1595 @item --install=@var{package} @dots{}
1596 @itemx -i @var{package} @dots{}
1597 Install the specified @var{package}s.
1599 Each @var{package} may specify either a simple package name, such as
1600 @code{guile}, or a package name followed by an at-sign and version number,
1601 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1602 case, the newest version prefixed by @code{1.8} is selected.)
1604 If no version number is specified, the
1605 newest available version will be selected. In addition, @var{package}
1606 may contain a colon, followed by the name of one of the outputs of the
1607 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1608 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1609 name (and optionally version) are searched for among the GNU
1610 distribution modules (@pxref{Package Modules}).
1612 @cindex propagated inputs
1613 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1614 that automatically get installed along with the required package
1615 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1616 @code{package} objects}, for information about propagated inputs in
1617 package definitions).
1619 @anchor{package-cmd-propagated-inputs}
1620 An example is the GNU MPC library: its C header files refer to those of
1621 the GNU MPFR library, which in turn refer to those of the GMP library.
1622 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1623 in the profile; removing MPC also removes MPFR and GMP---unless they had
1624 also been explicitly installed by the user.
1626 Besides, packages sometimes rely on the definition of environment
1627 variables for their search paths (see explanation of
1628 @code{--search-paths} below). Any missing or possibly incorrect
1629 environment variable definitions are reported here.
1631 @item --install-from-expression=@var{exp}
1633 Install the package @var{exp} evaluates to.
1635 @var{exp} must be a Scheme expression that evaluates to a
1636 @code{<package>} object. This option is notably useful to disambiguate
1637 between same-named variants of a package, with expressions such as
1638 @code{(@@ (gnu packages base) guile-final)}.
1640 Note that this option installs the first output of the specified
1641 package, which may be insufficient when needing a specific output of a
1642 multiple-output package.
1644 @item --install-from-file=@var{file}
1645 @itemx -f @var{file}
1646 Install the package that the code within @var{file} evaluates to.
1648 As an example, @var{file} might contain a definition like this
1649 (@pxref{Defining Packages}):
1652 @verbatiminclude package-hello.scm
1655 Developers may find it useful to include such a @file{guix.scm} file
1656 in the root of their project source tree that can be used to test
1657 development snapshots and create reproducible development environments
1658 (@pxref{Invoking guix environment}).
1660 @item --remove=@var{package} @dots{}
1661 @itemx -r @var{package} @dots{}
1662 Remove the specified @var{package}s.
1664 As for @code{--install}, each @var{package} may specify a version number
1665 and/or output name in addition to the package name. For instance,
1666 @code{-r glibc:debug} would remove the @code{debug} output of
1669 @item --upgrade[=@var{regexp} @dots{}]
1670 @itemx -u [@var{regexp} @dots{}]
1671 @cindex upgrading packages
1672 Upgrade all the installed packages. If one or more @var{regexp}s are
1673 specified, upgrade only installed packages whose name matches a
1674 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1676 Note that this upgrades package to the latest version of packages found
1677 in the distribution currently installed. To update your distribution,
1678 you should regularly run @command{guix pull} (@pxref{Invoking guix
1681 @item --do-not-upgrade[=@var{regexp} @dots{}]
1682 When used together with the @code{--upgrade} option, do @emph{not}
1683 upgrade any packages whose name matches a @var{regexp}. For example, to
1684 upgrade all packages in the current profile except those containing the
1685 substring ``emacs'':
1688 $ guix package --upgrade . --do-not-upgrade emacs
1691 @item @anchor{profile-manifest}--manifest=@var{file}
1692 @itemx -m @var{file}
1693 @cindex profile declaration
1694 @cindex profile manifest
1695 Create a new generation of the profile from the manifest object
1696 returned by the Scheme code in @var{file}.
1698 This allows you to @emph{declare} the profile's contents rather than
1699 constructing it through a sequence of @code{--install} and similar
1700 commands. The advantage is that @var{file} can be put under version
1701 control, copied to different machines to reproduce the same profile, and
1704 @c FIXME: Add reference to (guix profile) documentation when available.
1705 @var{file} must return a @dfn{manifest} object, which is roughly a list
1708 @findex packages->manifest
1710 (use-package-modules guile emacs)
1715 ;; Use a specific package output.
1716 (list guile-2.0 "debug")))
1719 @findex specification->package+output
1720 In this example we have to know which modules define the @code{emacs}
1721 and @code{guile-2.0} variables to provide the right
1722 @code{use-package-modules} line, which can be cumbersome. We can
1723 instead provide regular package specifications and let
1724 @code{specification->package-output} look up the corresponding package
1729 (map (compose list specification->package+output)
1730 '("emacs" "guile@@2.0" "guile@@2.0:debug")))
1734 @cindex rolling back
1735 @cindex undoing transactions
1736 @cindex transactions, undoing
1737 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1738 the last transaction.
1740 When combined with options such as @code{--install}, roll back occurs
1741 before any other actions.
1743 When rolling back from the first generation that actually contains
1744 installed packages, the profile is made to point to the @dfn{zeroth
1745 generation}, which contains no files apart from its own metadata.
1747 After having rolled back, installing, removing, or upgrading packages
1748 overwrites previous future generations. Thus, the history of the
1749 generations in a profile is always linear.
1751 @item --switch-generation=@var{pattern}
1752 @itemx -S @var{pattern}
1754 Switch to a particular generation defined by @var{pattern}.
1756 @var{pattern} may be either a generation number or a number prefixed
1757 with ``+'' or ``-''. The latter means: move forward/backward by a
1758 specified number of generations. For example, if you want to return to
1759 the latest generation after @code{--roll-back}, use
1760 @code{--switch-generation=+1}.
1762 The difference between @code{--roll-back} and
1763 @code{--switch-generation=-1} is that @code{--switch-generation} will
1764 not make a zeroth generation, so if a specified generation does not
1765 exist, the current generation will not be changed.
1767 @item --search-paths[=@var{kind}]
1768 @cindex search paths
1769 Report environment variable definitions, in Bash syntax, that may be
1770 needed in order to use the set of installed packages. These environment
1771 variables are used to specify @dfn{search paths} for files used by some
1772 of the installed packages.
1774 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1775 environment variables to be defined so it can look for headers and
1776 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1777 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1778 library are installed in the profile, then @code{--search-paths} will
1779 suggest setting these variables to @code{@var{profile}/include} and
1780 @code{@var{profile}/lib}, respectively.
1782 The typical use case is to define these environment variables in the
1786 $ eval `guix package --search-paths`
1789 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1790 meaning that the returned environment variable definitions will either
1791 be exact settings, or prefixes or suffixes of the current value of these
1792 variables. When omitted, @var{kind} defaults to @code{exact}.
1794 This option can also be used to compute the @emph{combined} search paths
1795 of several profiles. Consider this example:
1798 $ guix package -p foo -i guile
1799 $ guix package -p bar -i guile-json
1800 $ guix package -p foo -p bar --search-paths
1803 The last command above reports about the @code{GUILE_LOAD_PATH}
1804 variable, even though, taken individually, neither @file{foo} nor
1805 @file{bar} would lead to that recommendation.
1808 @item --profile=@var{profile}
1809 @itemx -p @var{profile}
1810 Use @var{profile} instead of the user's default profile.
1813 Produce verbose output. In particular, emit the build log of the
1814 environment on the standard error port.
1817 Use the bootstrap Guile to build the profile. This option is only
1818 useful to distribution developers.
1822 In addition to these actions, @command{guix package} supports the
1823 following options to query the current state of a profile, or the
1824 availability of packages:
1828 @item --search=@var{regexp}
1829 @itemx -s @var{regexp}
1830 @cindex searching for packages
1831 List the available packages whose name, synopsis, or description matches
1832 @var{regexp}. Print all the metadata of matching packages in
1833 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1834 GNU recutils manual}).
1836 This allows specific fields to be extracted using the @command{recsel}
1837 command, for instance:
1840 $ guix package -s malloc | recsel -p name,version
1848 Similarly, to show the name of all the packages available under the
1849 terms of the GNU@tie{}LGPL version 3:
1852 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1859 It is also possible to refine search results using several @code{-s}
1860 flags. For example, the following command returns a list of board
1864 $ guix package -s '\<board\>' -s game | recsel -p name
1869 If we were to omit @code{-s game}, we would also get software packages
1870 that deal with printed circuit boards; removing the angle brackets
1871 around @code{board} would further add packages that have to do with
1874 And now for a more elaborate example. The following command searches
1875 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1876 libraries, and prints the name and synopsis of the matching packages:
1879 $ guix package -s crypto -s library | \
1880 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1884 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1885 information on @dfn{selection expressions} for @code{recsel -e}.
1887 @item --show=@var{package}
1888 Show details about @var{package}, taken from the list of available packages, in
1889 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1893 $ guix package --show=python | recsel -p name,version
1901 You may also specify the full name of a package to only get details about a
1902 specific version of it:
1904 $ guix package --show=python@@3.4 | recsel -p name,version
1911 @item --list-installed[=@var{regexp}]
1912 @itemx -I [@var{regexp}]
1913 List the currently installed packages in the specified profile, with the
1914 most recently installed packages shown last. When @var{regexp} is
1915 specified, list only installed packages whose name matches @var{regexp}.
1917 For each installed package, print the following items, separated by
1918 tabs: the package name, its version string, the part of the package that
1919 is installed (for instance, @code{out} for the default output,
1920 @code{include} for its headers, etc.), and the path of this package in
1923 @item --list-available[=@var{regexp}]
1924 @itemx -A [@var{regexp}]
1925 List packages currently available in the distribution for this system
1926 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
1927 installed packages whose name matches @var{regexp}.
1929 For each package, print the following items separated by tabs: its name,
1930 its version string, the parts of the package (@pxref{Packages with
1931 Multiple Outputs}), and the source location of its definition.
1933 @item --list-generations[=@var{pattern}]
1934 @itemx -l [@var{pattern}]
1936 Return a list of generations along with their creation dates; for each
1937 generation, show the installed packages, with the most recently
1938 installed packages shown last. Note that the zeroth generation is never
1941 For each installed package, print the following items, separated by
1942 tabs: the name of a package, its version string, the part of the package
1943 that is installed (@pxref{Packages with Multiple Outputs}), and the
1944 location of this package in the store.
1946 When @var{pattern} is used, the command returns only matching
1947 generations. Valid patterns include:
1950 @item @emph{Integers and comma-separated integers}. Both patterns denote
1951 generation numbers. For instance, @code{--list-generations=1} returns
1954 And @code{--list-generations=1,8,2} outputs three generations in the
1955 specified order. Neither spaces nor trailing commas are allowed.
1957 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
1958 specified generations and everything in between. Note that the start of
1959 a range must be smaller than its end.
1961 It is also possible to omit the endpoint. For example,
1962 @code{--list-generations=2..}, returns all generations starting from the
1965 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
1966 or months by passing an integer along with the first letter of the
1967 duration. For example, @code{--list-generations=20d} lists generations
1968 that are up to 20 days old.
1971 @item --delete-generations[=@var{pattern}]
1972 @itemx -d [@var{pattern}]
1973 When @var{pattern} is omitted, delete all generations except the current
1976 This command accepts the same patterns as @option{--list-generations}.
1977 When @var{pattern} is specified, delete the matching generations. When
1978 @var{pattern} specifies a duration, generations @emph{older} than the
1979 specified duration match. For instance, @code{--delete-generations=1m}
1980 deletes generations that are more than one month old.
1982 If the current generation matches, it is @emph{not} deleted. Also, the
1983 zeroth generation is never deleted.
1985 Note that deleting generations prevents rolling back to them.
1986 Consequently, this command must be used with care.
1990 Finally, since @command{guix package} may actually start build
1991 processes, it supports all the common build options (@pxref{Common Build
1992 Options}). It also supports package transformation options, such as
1993 @option{--with-source} (@pxref{Package Transformation Options}).
1994 However, note that package transformations are lost when upgrading; to
1995 preserve transformations across upgrades, you should define your own
1996 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
1997 (@pxref{Defining Packages}).
2001 @section Substitutes
2004 @cindex pre-built binaries
2005 Guix supports transparent source/binary deployment, which means that it
2006 can either build things locally, or download pre-built items from a
2007 server. We call these pre-built items @dfn{substitutes}---they are
2008 substitutes for local build results. In many cases, downloading a
2009 substitute is much faster than building things locally.
2011 Substitutes can be anything resulting from a derivation build
2012 (@pxref{Derivations}). Of course, in the common case, they are
2013 pre-built package binaries, but source tarballs, for instance, which
2014 also result from derivation builds, can be available as substitutes.
2016 The @code{hydra.gnu.org} server is a front-end to a build farm that
2017 builds packages from the GNU distribution continuously for some
2018 architectures, and makes them available as substitutes. This is the
2019 default source of substitutes; it can be overridden by passing the
2020 @option{--substitute-urls} option either to @command{guix-daemon}
2021 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2022 or to client tools such as @command{guix package}
2023 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2026 Substitute URLs can be either HTTP or HTTPS.
2027 HTTPS is recommended because communications are encrypted; conversely,
2028 using HTTP makes all communications visible to an eavesdropper, who
2029 could use the information gathered to determine, for instance, whether
2030 your system has unpatched security vulnerabilities.
2033 @cindex digital signatures
2034 @cindex substitutes, authorization thereof
2035 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2037 must add its public key to the access control list (ACL) of archive
2038 imports, using the @command{guix archive} command (@pxref{Invoking guix
2039 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2040 be compromised and to serve genuine substitutes.
2042 This public key is installed along with Guix, in
2043 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2044 the installation prefix of Guix. If you installed Guix from source,
2045 make sure you checked the GPG signature of
2046 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2047 Then, you can run something like this:
2050 # guix archive --authorize < hydra.gnu.org.pub
2053 Once this is in place, the output of a command like @code{guix build}
2054 should change from something like:
2057 $ guix build emacs --dry-run
2058 The following derivations would be built:
2059 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2060 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2061 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2062 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2070 $ guix build emacs --dry-run
2071 The following files would be downloaded:
2072 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2073 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2074 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2075 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2080 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2081 will be downloaded, when possible, for future builds.
2083 Guix ignores substitutes that are not signed, or that are not signed by
2084 one of the keys listed in the ACL. It also detects and raises an error
2085 when attempting to use a substitute that has been tampered with.
2088 Substitutes are downloaded over HTTP or HTTPS.
2089 The @code{http_proxy} environment
2090 variable can be set in the environment of @command{guix-daemon} and is
2091 honored for downloads of substitutes. Note that the value of
2092 @code{http_proxy} in the environment where @command{guix build},
2093 @command{guix package}, and other client commands are run has
2094 @emph{absolutely no effect}.
2096 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2097 (in other words, the server is not authenticated), contrary to what
2098 HTTPS clients such as Web browsers usually do. This is because Guix
2099 authenticates substitute information itself, as explained above, which
2100 is what we care about (whereas X.509 certificates are about
2101 authenticating bindings between domain names and public keys.)
2103 The substitute mechanism can be disabled globally by running
2104 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2105 guix-daemon}). It can also be disabled temporarily by passing the
2106 @code{--no-substitutes} option to @command{guix package}, @command{guix
2107 build}, and other command-line tools.
2110 @unnumberedsubsec On Trusting Binaries
2112 Today, each individual's control over their own computing is at the
2113 mercy of institutions, corporations, and groups with enough power and
2114 determination to subvert the computing infrastructure and exploit its
2115 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2116 convenient, we encourage users to also build on their own, or even run
2117 their own build farm, such that @code{hydra.gnu.org} is less of an
2118 interesting target. One way to help is by publishing the software you
2119 build using @command{guix publish} so that others have one more choice
2120 of server to download substitutes from (@pxref{Invoking guix publish}).
2122 Guix has the foundations to maximize build reproducibility
2123 (@pxref{Features}). In most cases, independent builds of a given
2124 package or derivation should yield bit-identical results. Thus, through
2125 a diverse set of independent package builds, we can strengthen the
2126 integrity of our systems. The @command{guix challenge} command aims to
2127 help users assess substitute servers, and to assist developers in
2128 finding out about non-deterministic package builds (@pxref{Invoking guix
2129 challenge}). Similarly, the @option{--check} option of @command{guix
2130 build} allows users to check whether previously-installed substitutes
2131 are genuine by rebuilding them locally (@pxref{build-check,
2132 @command{guix build --check}}).
2134 In the future, we want Guix to have support to publish and retrieve
2135 binaries to/from other users, in a peer-to-peer fashion. If you would
2136 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2139 @node Packages with Multiple Outputs
2140 @section Packages with Multiple Outputs
2142 @cindex multiple-output packages
2143 @cindex package outputs
2146 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2147 source package leads to exactly one directory in the store. When running
2148 @command{guix package -i glibc}, one installs the default output of the
2149 GNU libc package; the default output is called @code{out}, but its name
2150 can be omitted as shown in this command. In this particular case, the
2151 default output of @code{glibc} contains all the C header files, shared
2152 libraries, static libraries, Info documentation, and other supporting
2155 Sometimes it is more appropriate to separate the various types of files
2156 produced from a single source package into separate outputs. For
2157 instance, the GLib C library (used by GTK+ and related packages)
2158 installs more than 20 MiB of reference documentation as HTML pages.
2159 To save space for users who do not need it, the documentation goes to a
2160 separate output, called @code{doc}. To install the main GLib output,
2161 which contains everything but the documentation, one would run:
2164 guix package -i glib
2167 @cindex documentation
2168 The command to install its documentation is:
2171 guix package -i glib:doc
2174 Some packages install programs with different ``dependency footprints''.
2175 For instance, the WordNet package installs both command-line tools and
2176 graphical user interfaces (GUIs). The former depend solely on the C
2177 library, whereas the latter depend on Tcl/Tk and the underlying X
2178 libraries. In this case, we leave the command-line tools in the default
2179 output, whereas the GUIs are in a separate output. This allows users
2180 who do not need the GUIs to save space. The @command{guix size} command
2181 can help find out about such situations (@pxref{Invoking guix size}).
2182 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2184 There are several such multiple-output packages in the GNU distribution.
2185 Other conventional output names include @code{lib} for libraries and
2186 possibly header files, @code{bin} for stand-alone programs, and
2187 @code{debug} for debugging information (@pxref{Installing Debugging
2188 Files}). The outputs of a packages are listed in the third column of
2189 the output of @command{guix package --list-available} (@pxref{Invoking
2193 @node Invoking guix gc
2194 @section Invoking @command{guix gc}
2196 @cindex garbage collector
2198 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2199 The @command{guix gc} command allows users to explicitly run the garbage
2200 collector to reclaim space from the @file{/gnu/store} directory. It is
2201 the @emph{only} way to remove files from @file{/gnu/store}---removing
2202 files or directories manually may break it beyond repair!
2204 The garbage collector has a set of known @dfn{roots}: any file under
2205 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2206 cannot be deleted; any other file is considered @dfn{dead} and may be
2207 deleted. The set of garbage collector roots includes default user
2208 profiles, and may be augmented with @command{guix build --root}, for
2209 example (@pxref{Invoking guix build}).
2211 Prior to running @code{guix gc --collect-garbage} to make space, it is
2212 often useful to remove old generations from user profiles; that way, old
2213 package builds referenced by those generations can be reclaimed. This
2214 is achieved by running @code{guix package --delete-generations}
2215 (@pxref{Invoking guix package}).
2217 The @command{guix gc} command has three modes of operation: it can be
2218 used to garbage-collect any dead files (the default), to delete specific
2219 files (the @code{--delete} option), to print garbage-collector
2220 information, or for more advanced queries. The garbage collection
2221 options are as follows:
2224 @item --collect-garbage[=@var{min}]
2225 @itemx -C [@var{min}]
2226 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2227 sub-directories. This is the default operation when no option is
2230 When @var{min} is given, stop once @var{min} bytes have been collected.
2231 @var{min} may be a number of bytes, or it may include a unit as a
2232 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2233 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2235 When @var{min} is omitted, collect all the garbage.
2237 @item --free-space=@var{free}
2238 @itemx -F @var{free}
2239 Collect garbage until @var{free} space is available under
2240 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2241 as @code{500MiB}, as described above.
2243 When @var{free} or more is already available in @file{/gnu/store}, do
2244 nothing and exit immediately.
2248 Attempt to delete all the store files and directories specified as
2249 arguments. This fails if some of the files are not in the store, or if
2250 they are still live.
2252 @item --list-failures
2253 List store items corresponding to cached build failures.
2255 This prints nothing unless the daemon was started with
2256 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2257 @option{--cache-failures}}).
2259 @item --clear-failures
2260 Remove the specified store items from the failed-build cache.
2262 Again, this option only makes sense when the daemon is started with
2263 @option{--cache-failures}. Otherwise, it does nothing.
2266 Show the list of dead files and directories still present in the
2267 store---i.e., files and directories no longer reachable from any root.
2270 Show the list of live store files and directories.
2274 In addition, the references among existing store files can be queried:
2280 @cindex package dependencies
2281 List the references (respectively, the referrers) of store files given
2287 List the requisites of the store files passed as arguments. Requisites
2288 include the store files themselves, their references, and the references
2289 of these, recursively. In other words, the returned list is the
2290 @dfn{transitive closure} of the store files.
2292 @xref{Invoking guix size}, for a tool to profile the size of the closure
2293 of an element. @xref{Invoking guix graph}, for a tool to visualize
2294 the graph of references.
2298 Lastly, the following options allow you to check the integrity of the
2299 store and to control disk usage.
2303 @item --verify[=@var{options}]
2304 @cindex integrity, of the store
2305 @cindex integrity checking
2306 Verify the integrity of the store.
2308 By default, make sure that all the store items marked as valid in the
2309 database of the daemon actually exist in @file{/gnu/store}.
2311 When provided, @var{options} must be a comma-separated list containing one
2312 or more of @code{contents} and @code{repair}.
2314 When passing @option{--verify=contents}, the daemon computes the
2315 content hash of each store item and compares it against its hash in the
2316 database. Hash mismatches are reported as data corruptions. Because it
2317 traverses @emph{all the files in the store}, this command can take a
2318 long time, especially on systems with a slow disk drive.
2320 @cindex repairing the store
2321 @cindex corruption, recovering from
2322 Using @option{--verify=repair} or @option{--verify=contents,repair}
2323 causes the daemon to try to repair corrupt store items by fetching
2324 substitutes for them (@pxref{Substitutes}). Because repairing is not
2325 atomic, and thus potentially dangerous, it is available only to the
2326 system administrator. A lightweight alternative, when you know exactly
2327 which items in the store are corrupt, is @command{guix build --repair}
2328 (@pxref{Invoking guix build}).
2331 @cindex deduplication
2332 Optimize the store by hard-linking identical files---this is
2333 @dfn{deduplication}.
2335 The daemon performs deduplication after each successful build or archive
2336 import, unless it was started with @code{--disable-deduplication}
2337 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2338 this option is primarily useful when the daemon was running with
2339 @code{--disable-deduplication}.
2343 @node Invoking guix pull
2344 @section Invoking @command{guix pull}
2346 @cindex upgrading Guix
2347 @cindex updating Guix
2348 @cindex @command{guix pull}
2350 Packages are installed or upgraded to the latest version available in
2351 the distribution currently available on your local machine. To update
2352 that distribution, along with the Guix tools, you must run @command{guix
2353 pull}: the command downloads the latest Guix source code and package
2354 descriptions, and deploys it.
2356 On completion, @command{guix package} will use packages and package
2357 versions from this just-retrieved copy of Guix. Not only that, but all
2358 the Guix commands and Scheme modules will also be taken from that latest
2359 version. New @command{guix} sub-commands added by the update also
2362 Any user can update their Guix copy using @command{guix pull}, and the
2363 effect is limited to the user who run @command{guix pull}. For
2364 instance, when user @code{root} runs @command{guix pull}, this has no
2365 effect on the version of Guix that user @code{alice} sees, and vice
2366 versa@footnote{Under the hood, @command{guix pull} updates the
2367 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2368 and the @command{guix} command loads code from there. Currently, the
2369 only way to roll back an invocation of @command{guix pull} is to
2370 manually update this symlink to point to the previous Guix.}.
2372 The @command{guix pull} command is usually invoked with no arguments,
2373 but it supports the following options:
2377 Produce verbose output, writing build logs to the standard error output.
2379 @item --url=@var{url}
2380 Download the source tarball of Guix from @var{url}.
2382 By default, the tarball is taken from its canonical address at
2383 @code{gnu.org}, for the stable branch of Guix.
2385 With some Git servers, this can be used to deploy any version of Guix.
2386 For example, to download and deploy version 0.12.0 of Guix from the
2390 guix pull --url=http://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.12.0.tar.gz
2393 It can also be used to deploy arbitrary Git revisions:
2396 guix pull --url=http://git.savannah.gnu.org/cgit/guix.git/snapshot/74d862e8a.tar.gz
2400 Use the bootstrap Guile to build the latest Guix. This option is only
2401 useful to Guix developers.
2405 @node Invoking guix pack
2406 @section Invoking @command{guix pack}
2408 Occasionally you want to pass software to people who are not (yet!)
2409 lucky enough to be using Guix. You'd tell them to run @command{guix
2410 package -i @var{something}}, but that's not possible in this case. This
2411 is where @command{guix pack} comes in.
2415 @cindex application bundle
2416 @cindex software bundle
2417 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2418 @dfn{software bundle}: it creates a tarball or some other archive
2419 containing the binaries of the software you're interested in, and all
2420 its dependencies. The resulting archive can be used on any machine that
2421 does not have Guix, and people can run the exact same binaries as those
2422 you have with Guix. The pack itself is created in a bit-reproducible
2423 fashion, so anyone can verify that it really contains the build results
2424 that you pretend to be shipping.
2426 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2427 their dependencies, you can run:
2430 $ guix pack guile emacs geiser
2432 /gnu/store/@dots{}-pack.tar.gz
2435 The result here is a tarball containing a @file{/gnu/store} directory
2436 with all the relevant packages. The resulting tarball contains a
2437 @dfn{profile} with the three packages of interest; the profile is the
2438 same as would be created by @command{guix package -i}. It is this
2439 mechanism that is used to create Guix's own standalone binary tarball
2440 (@pxref{Binary Installation}).
2442 Users of this pack would have to run
2443 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2444 find inconvenient. To work around it, you can create, say, a
2445 @file{/opt/gnu/bin} symlink to the profile:
2448 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2452 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2454 Alternatively, you can produce a pack in the Docker image format using
2455 the following command:
2458 guix pack -f docker guile emacs geiser
2462 The result is a tarball that can be passed to the @command{docker load}
2464 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2465 documentation} for more information.
2467 Several command-line options allow you to customize your pack:
2470 @item --format=@var{format}
2471 @itemx -f @var{format}
2472 Produce a pack in the given @var{format}.
2474 The available formats are:
2478 This is the default format. It produces a tarball containing all the
2479 specifies binaries and symlinks.
2482 This produces a tarball that follows the
2483 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2484 Docker Image Specification}.
2487 @item --expression=@var{expr}
2488 @itemx -e @var{expr}
2489 Consider the package @var{expr} evaluates to.
2491 This has the same purpose as the same-named option in @command{guix
2492 build} (@pxref{Additional Build Options, @code{--expression} in
2493 @command{guix build}}).
2495 @item --system=@var{system}
2496 @itemx -s @var{system}
2497 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2498 the system type of the build host.
2500 @item --target=@var{triplet}
2501 @cindex cross-compilation
2502 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2503 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2504 configuration triplets,, autoconf, Autoconf}).
2506 @item --compression=@var{tool}
2507 @itemx -C @var{tool}
2508 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2509 @code{bzip2}, @code{xz}, or @code{lzip}.
2511 @item --symlink=@var{spec}
2512 @itemx -S @var{spec}
2513 Add the symlinks specified by @var{spec} to the pack. This option can
2514 appear several times.
2516 @var{spec} has the form @code{@var{source}=@var{target}}, where
2517 @var{source} is the symlink that will be created and @var{target} is the
2520 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2521 symlink pointing to the @file{bin} sub-directory of the profile.
2523 @item --localstatedir
2524 Include the ``local state directory'', @file{/var/guix}, in the
2527 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2528 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2529 the pack means that the store is ``complete'' and manageable by Guix;
2530 not providing it pack means that the store is ``dead'': items cannot be
2531 added to it or removed from it after extraction of the pack.
2533 One use case for this is the Guix self-contained binary tarball
2534 (@pxref{Binary Installation}).
2537 In addition, @command{guix pack} supports all the common build options
2538 (@pxref{Common Build Options}) and all the package transformation
2539 options (@pxref{Package Transformation Options}).
2542 @node Invoking guix archive
2543 @section Invoking @command{guix archive}
2545 @cindex @command{guix archive}
2547 The @command{guix archive} command allows users to @dfn{export} files
2548 from the store into a single archive, and to later @dfn{import} them.
2549 In particular, it allows store files to be transferred from one machine
2550 to the store on another machine.
2552 @cindex exporting store items
2553 To export store files as an archive to standard output, run:
2556 guix archive --export @var{options} @var{specifications}...
2559 @var{specifications} may be either store file names or package
2560 specifications, as for @command{guix package} (@pxref{Invoking guix
2561 package}). For instance, the following command creates an archive
2562 containing the @code{gui} output of the @code{git} package and the main
2563 output of @code{emacs}:
2566 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2569 If the specified packages are not built yet, @command{guix archive}
2570 automatically builds them. The build process may be controlled with the
2571 common build options (@pxref{Common Build Options}).
2573 To transfer the @code{emacs} package to a machine connected over SSH,
2577 guix archive --export -r emacs | ssh the-machine guix archive --import
2581 Similarly, a complete user profile may be transferred from one machine
2582 to another like this:
2585 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2586 ssh the-machine guix-archive --import
2590 However, note that, in both examples, all of @code{emacs} and the
2591 profile as well as all of their dependencies are transferred (due to
2592 @code{-r}), regardless of what is already available in the store on the
2593 target machine. The @code{--missing} option can help figure out which
2594 items are missing from the target store. The @command{guix copy}
2595 command simplifies and optimizes this whole process, so this is probably
2596 what you should use in this case (@pxref{Invoking guix copy}).
2598 @cindex nar, archive format
2599 @cindex normalized archive (nar)
2600 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2601 comparable in spirit to `tar', but with differences
2602 that make it more appropriate for our purposes. First, rather than
2603 recording all Unix metadata for each file, the nar format only mentions
2604 the file type (regular, directory, or symbolic link); Unix permissions
2605 and owner/group are dismissed. Second, the order in which directory
2606 entries are stored always follows the order of file names according to
2607 the C locale collation order. This makes archive production fully
2610 When exporting, the daemon digitally signs the contents of the archive,
2611 and that digital signature is appended. When importing, the daemon
2612 verifies the signature and rejects the import in case of an invalid
2613 signature or if the signing key is not authorized.
2614 @c FIXME: Add xref to daemon doc about signatures.
2616 The main options are:
2620 Export the specified store files or packages (see below.) Write the
2621 resulting archive to the standard output.
2623 Dependencies are @emph{not} included in the output, unless
2624 @code{--recursive} is passed.
2628 When combined with @code{--export}, this instructs @command{guix
2629 archive} to include dependencies of the given items in the archive.
2630 Thus, the resulting archive is self-contained: it contains the closure
2631 of the exported store items.
2634 Read an archive from the standard input, and import the files listed
2635 therein into the store. Abort if the archive has an invalid digital
2636 signature, or if it is signed by a public key not among the authorized
2637 keys (see @code{--authorize} below.)
2640 Read a list of store file names from the standard input, one per line,
2641 and write on the standard output the subset of these files missing from
2644 @item --generate-key[=@var{parameters}]
2645 @cindex signing, archives
2646 Generate a new key pair for the daemon. This is a prerequisite before
2647 archives can be exported with @code{--export}. Note that this operation
2648 usually takes time, because it needs to gather enough entropy to
2649 generate the key pair.
2651 The generated key pair is typically stored under @file{/etc/guix}, in
2652 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2653 key, which must be kept secret.) When @var{parameters} is omitted,
2654 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2655 versions before 1.6.0, it is a 4096-bit RSA key.
2656 Alternatively, @var{parameters} can specify
2657 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2658 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2659 Libgcrypt Reference Manual}).
2662 @cindex authorizing, archives
2663 Authorize imports signed by the public key passed on standard input.
2664 The public key must be in ``s-expression advanced format''---i.e., the
2665 same format as the @file{signing-key.pub} file.
2667 The list of authorized keys is kept in the human-editable file
2668 @file{/etc/guix/acl}. The file contains
2669 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2670 s-expressions''} and is structured as an access-control list in the
2671 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2674 @item --extract=@var{directory}
2675 @itemx -x @var{directory}
2676 Read a single-item archive as served by substitute servers
2677 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2678 low-level operation needed in only very narrow use cases; see below.
2680 For example, the following command extracts the substitute for Emacs
2681 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2685 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2686 | bunzip2 | guix archive -x /tmp/emacs
2689 Single-item archives are different from multiple-item archives produced
2690 by @command{guix archive --export}; they contain a single store item,
2691 and they do @emph{not} embed a signature. Thus this operation does
2692 @emph{no} signature verification and its output should be considered
2695 The primary purpose of this operation is to facilitate inspection of
2696 archive contents coming from possibly untrusted substitute servers.
2700 @c *********************************************************************
2701 @node Programming Interface
2702 @chapter Programming Interface
2704 GNU Guix provides several Scheme programming interfaces (APIs) to
2705 define, build, and query packages. The first interface allows users to
2706 write high-level package definitions. These definitions refer to
2707 familiar packaging concepts, such as the name and version of a package,
2708 its build system, and its dependencies. These definitions can then be
2709 turned into concrete build actions.
2711 Build actions are performed by the Guix daemon, on behalf of users. In a
2712 standard setup, the daemon has write access to the store---the
2713 @file{/gnu/store} directory---whereas users do not. The recommended
2714 setup also has the daemon perform builds in chroots, under a specific
2715 build users, to minimize interference with the rest of the system.
2718 Lower-level APIs are available to interact with the daemon and the
2719 store. To instruct the daemon to perform a build action, users actually
2720 provide it with a @dfn{derivation}. A derivation is a low-level
2721 representation of the build actions to be taken, and the environment in
2722 which they should occur---derivations are to package definitions what
2723 assembly is to C programs. The term ``derivation'' comes from the fact
2724 that build results @emph{derive} from them.
2726 This chapter describes all these APIs in turn, starting from high-level
2727 package definitions.
2730 * Defining Packages:: Defining new packages.
2731 * Build Systems:: Specifying how packages are built.
2732 * The Store:: Manipulating the package store.
2733 * Derivations:: Low-level interface to package derivations.
2734 * The Store Monad:: Purely functional interface to the store.
2735 * G-Expressions:: Manipulating build expressions.
2738 @node Defining Packages
2739 @section Defining Packages
2741 The high-level interface to package definitions is implemented in the
2742 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2743 example, the package definition, or @dfn{recipe}, for the GNU Hello
2744 package looks like this:
2747 (define-module (gnu packages hello)
2748 #:use-module (guix packages)
2749 #:use-module (guix download)
2750 #:use-module (guix build-system gnu)
2751 #:use-module (guix licenses)
2752 #:use-module (gnu packages gawk))
2754 (define-public hello
2760 (uri (string-append "mirror://gnu/hello/hello-" version
2764 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2765 (build-system gnu-build-system)
2766 (arguments '(#:configure-flags '("--enable-silent-rules")))
2767 (inputs `(("gawk" ,gawk)))
2768 (synopsis "Hello, GNU world: An example GNU package")
2769 (description "Guess what GNU Hello prints!")
2770 (home-page "http://www.gnu.org/software/hello/")
2775 Without being a Scheme expert, the reader may have guessed the meaning
2776 of the various fields here. This expression binds the variable
2777 @code{hello} to a @code{<package>} object, which is essentially a record
2778 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2779 This package object can be inspected using procedures found in the
2780 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2781 returns---surprise!---@code{"hello"}.
2783 With luck, you may be able to import part or all of the definition of
2784 the package you are interested in from another repository, using the
2785 @code{guix import} command (@pxref{Invoking guix import}).
2787 In the example above, @var{hello} is defined in a module of its own,
2788 @code{(gnu packages hello)}. Technically, this is not strictly
2789 necessary, but it is convenient to do so: all the packages defined in
2790 modules under @code{(gnu packages @dots{})} are automatically known to
2791 the command-line tools (@pxref{Package Modules}).
2793 There are a few points worth noting in the above package definition:
2797 The @code{source} field of the package is an @code{<origin>} object
2798 (@pxref{origin Reference}, for the complete reference).
2799 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2800 meaning that the source is a file to be downloaded over FTP or HTTP.
2802 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2803 the GNU mirrors defined in @code{(guix download)}.
2805 The @code{sha256} field specifies the expected SHA256 hash of the file
2806 being downloaded. It is mandatory, and allows Guix to check the
2807 integrity of the file. The @code{(base32 @dots{})} form introduces the
2808 base32 representation of the hash. You can obtain this information with
2809 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2810 hash} (@pxref{Invoking guix hash}).
2813 When needed, the @code{origin} form can also have a @code{patches} field
2814 listing patches to be applied, and a @code{snippet} field giving a
2815 Scheme expression to modify the source code.
2818 @cindex GNU Build System
2819 The @code{build-system} field specifies the procedure to build the
2820 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2821 represents the familiar GNU Build System, where packages may be
2822 configured, built, and installed with the usual @code{./configure &&
2823 make && make check && make install} command sequence.
2826 The @code{arguments} field specifies options for the build system
2827 (@pxref{Build Systems}). Here it is interpreted by
2828 @var{gnu-build-system} as a request run @file{configure} with the
2829 @code{--enable-silent-rules} flag.
2835 What about these quote (@code{'}) characters? They are Scheme syntax to
2836 introduce a literal list; @code{'} is synonymous with @code{quote}.
2837 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2838 for details. Here the value of the @code{arguments} field is a list of
2839 arguments passed to the build system down the road, as with @code{apply}
2840 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2843 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2844 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2845 @code{#:configure-flags} is a keyword used to pass a keyword argument
2846 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2850 The @code{inputs} field specifies inputs to the build process---i.e.,
2851 build-time or run-time dependencies of the package. Here, we define an
2852 input called @code{"gawk"} whose value is that of the @var{gawk}
2853 variable; @var{gawk} is itself bound to a @code{<package>} object.
2855 @cindex backquote (quasiquote)
2858 @cindex comma (unquote)
2862 @findex unquote-splicing
2863 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2864 us to introduce a literal list in the @code{inputs} field, while
2865 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2866 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2869 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2870 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2871 of ensuring that they are present (@pxref{Build Systems}).
2873 However, any other dependencies need to be specified in the
2874 @code{inputs} field. Any dependency not specified here will simply be
2875 unavailable to the build process, possibly leading to a build failure.
2878 @xref{package Reference}, for a full description of possible fields.
2880 Once a package definition is in place, the
2881 package may actually be built using the @code{guix build} command-line
2882 tool (@pxref{Invoking guix build}). You can easily jump back to the
2883 package definition using the @command{guix edit} command
2884 (@pxref{Invoking guix edit}).
2885 @xref{Packaging Guidelines}, for
2886 more information on how to test package definitions, and
2887 @ref{Invoking guix lint}, for information on how to check a definition
2888 for style conformance.
2890 Finally, updating the package definition to a new upstream version
2891 can be partly automated by the @command{guix refresh} command
2892 (@pxref{Invoking guix refresh}).
2894 Behind the scenes, a derivation corresponding to the @code{<package>}
2895 object is first computed by the @code{package-derivation} procedure.
2896 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
2897 The build actions it prescribes may then be realized by using the
2898 @code{build-derivations} procedure (@pxref{The Store}).
2900 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
2901 Return the @code{<derivation>} object of @var{package} for @var{system}
2902 (@pxref{Derivations}).
2904 @var{package} must be a valid @code{<package>} object, and @var{system}
2905 must be a string denoting the target system type---e.g.,
2906 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
2907 must be a connection to the daemon, which operates on the store
2908 (@pxref{The Store}).
2912 @cindex cross-compilation
2913 Similarly, it is possible to compute a derivation that cross-builds a
2914 package for some other system:
2916 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
2917 @var{package} @var{target} [@var{system}]
2918 Return the @code{<derivation>} object of @var{package} cross-built from
2919 @var{system} to @var{target}.
2921 @var{target} must be a valid GNU triplet denoting the target hardware
2922 and operating system, such as @code{"mips64el-linux-gnu"}
2923 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
2924 Configure and Build System}).
2927 @cindex package transformations
2928 @cindex input rewriting
2929 @cindex dependency tree rewriting
2930 Packages can be manipulated in arbitrary ways. An example of a useful
2931 transformation is @dfn{input rewriting}, whereby the dependency tree of
2932 a package is rewritten by replacing specific inputs by others:
2934 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
2935 [@var{rewrite-name}]
2936 Return a procedure that, when passed a package, replaces its direct and
2937 indirect dependencies (but not its implicit inputs) according to
2938 @var{replacements}. @var{replacements} is a list of package pairs; the
2939 first element of each pair is the package to replace, and the second one
2942 Optionally, @var{rewrite-name} is a one-argument procedure that takes
2943 the name of a package and returns its new name after rewrite.
2947 Consider this example:
2950 (define libressl-instead-of-openssl
2951 ;; This is a procedure to replace OPENSSL by LIBRESSL,
2953 (package-input-rewriting `((,openssl . ,libressl))))
2955 (define git-with-libressl
2956 (libressl-instead-of-openssl git))
2960 Here we first define a rewriting procedure that replaces @var{openssl}
2961 with @var{libressl}. Then we use it to define a @dfn{variant} of the
2962 @var{git} package that uses @var{libressl} instead of @var{openssl}.
2963 This is exactly what the @option{--with-input} command-line option does
2964 (@pxref{Package Transformation Options, @option{--with-input}}).
2966 A more generic procedure to rewrite a package dependency graph is
2967 @code{package-mapping}: it supports arbitrary changes to nodes in the
2970 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
2971 Return a procedure that, given a package, applies @var{proc} to all the packages
2972 depended on and returns the resulting package. The procedure stops recursion
2973 when @var{cut?} returns true for a given package.
2977 * package Reference :: The package data type.
2978 * origin Reference:: The origin data type.
2982 @node package Reference
2983 @subsection @code{package} Reference
2985 This section summarizes all the options available in @code{package}
2986 declarations (@pxref{Defining Packages}).
2988 @deftp {Data Type} package
2989 This is the data type representing a package recipe.
2993 The name of the package, as a string.
2995 @item @code{version}
2996 The version of the package, as a string.
2999 An object telling how the source code for the package should be
3000 acquired. Most of the time, this is an @code{origin} object, which
3001 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3002 can also be any other ``file-like'' object such as a @code{local-file},
3003 which denotes a file from the local file system (@pxref{G-Expressions,
3004 @code{local-file}}).
3006 @item @code{build-system}
3007 The build system that should be used to build the package (@pxref{Build
3010 @item @code{arguments} (default: @code{'()})
3011 The arguments that should be passed to the build system. This is a
3012 list, typically containing sequential keyword-value pairs.
3014 @item @code{inputs} (default: @code{'()})
3015 @itemx @code{native-inputs} (default: @code{'()})
3016 @itemx @code{propagated-inputs} (default: @code{'()})
3017 @cindex inputs, of packages
3018 These fields list dependencies of the package. Each one is a list of
3019 tuples, where each tuple has a label for the input (a string) as its
3020 first element, a package, origin, or derivation as its second element,
3021 and optionally the name of the output thereof that should be used, which
3022 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3023 more on package outputs). For example, the list below specifies three
3027 `(("libffi" ,libffi)
3028 ("libunistring" ,libunistring)
3029 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3032 @cindex cross compilation, package dependencies
3033 The distinction between @code{native-inputs} and @code{inputs} is
3034 necessary when considering cross-compilation. When cross-compiling,
3035 dependencies listed in @code{inputs} are built for the @emph{target}
3036 architecture; conversely, dependencies listed in @code{native-inputs}
3037 are built for the architecture of the @emph{build} machine.
3039 @code{native-inputs} is typically used to list tools needed at
3040 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3041 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3042 this area (@pxref{Invoking guix lint}).
3044 @anchor{package-propagated-inputs}
3045 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3046 specified packages will be automatically installed alongside the package
3047 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3048 package}}, for information on how @command{guix package} deals with
3051 For example this is necessary when a C/C++ library needs headers of
3052 another library to compile, or when a pkg-config file refers to another
3053 one @i{via} its @code{Requires} field.
3055 Another example where @code{propagated-inputs} is useful is for languages
3056 that lack a facility to record the run-time search path akin to the
3057 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3058 more. To ensure that libraries written in those languages can find
3059 library code they depend on at run time, run-time dependencies must be
3060 listed in @code{propagated-inputs} rather than @code{inputs}.
3062 @item @code{self-native-input?} (default: @code{#f})
3063 This is a Boolean field telling whether the package should use itself as
3064 a native input when cross-compiling.
3066 @item @code{outputs} (default: @code{'("out")})
3067 The list of output names of the package. @xref{Packages with Multiple
3068 Outputs}, for typical uses of additional outputs.
3070 @item @code{native-search-paths} (default: @code{'()})
3071 @itemx @code{search-paths} (default: @code{'()})
3072 A list of @code{search-path-specification} objects describing
3073 search-path environment variables honored by the package.
3075 @item @code{replacement} (default: @code{#f})
3076 This must be either @code{#f} or a package object that will be used as a
3077 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3080 @item @code{synopsis}
3081 A one-line description of the package.
3083 @item @code{description}
3084 A more elaborate description of the package.
3086 @item @code{license}
3087 @cindex license, of packages
3088 The license of the package; a value from @code{(guix licenses)},
3089 or a list of such values.
3091 @item @code{home-page}
3092 The URL to the home-page of the package, as a string.
3094 @item @code{supported-systems} (default: @var{%supported-systems})
3095 The list of systems supported by the package, as strings of the form
3096 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3098 @item @code{maintainers} (default: @code{'()})
3099 The list of maintainers of the package, as @code{maintainer} objects.
3101 @item @code{location} (default: source location of the @code{package} form)
3102 The source location of the package. It is useful to override this when
3103 inheriting from another package, in which case this field is not
3104 automatically corrected.
3109 @node origin Reference
3110 @subsection @code{origin} Reference
3112 This section summarizes all the options available in @code{origin}
3113 declarations (@pxref{Defining Packages}).
3115 @deftp {Data Type} origin
3116 This is the data type representing a source code origin.
3120 An object containing the URI of the source. The object type depends on
3121 the @code{method} (see below). For example, when using the
3122 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3123 values are: a URL represented as a string, or a list thereof.
3126 A procedure that handles the URI.
3131 @item @var{url-fetch} from @code{(guix download)}
3132 download a file from the HTTP, HTTPS, or FTP URL specified in the
3136 @item @var{git-fetch} from @code{(guix git-download)}
3137 clone the Git version control repository, and check out the revision
3138 specified in the @code{uri} field as a @code{git-reference} object; a
3139 @code{git-reference} looks like this:
3143 (url "git://git.debian.org/git/pkg-shadow/shadow")
3144 (commit "v4.1.5.1"))
3149 A bytevector containing the SHA-256 hash of the source. Typically the
3150 @code{base32} form is used here to generate the bytevector from a
3153 You can obtain this information using @code{guix download}
3154 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3157 @item @code{file-name} (default: @code{#f})
3158 The file name under which the source code should be saved. When this is
3159 @code{#f}, a sensible default value will be used in most cases. In case
3160 the source is fetched from a URL, the file name from the URL will be
3161 used. For version control checkouts, it is recommended to provide the
3162 file name explicitly because the default is not very descriptive.
3164 @item @code{patches} (default: @code{'()})
3165 A list of file names containing patches to be applied to the source.
3167 This list of patches must be unconditional. In particular, it cannot
3168 depend on the value of @code{%current-system} or
3169 @code{%current-target-system}.
3171 @item @code{snippet} (default: @code{#f})
3172 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3173 in the source directory. This is a convenient way to modify the source,
3174 sometimes more convenient than a patch.
3176 @item @code{patch-flags} (default: @code{'("-p1")})
3177 A list of command-line flags that should be passed to the @code{patch}
3180 @item @code{patch-inputs} (default: @code{#f})
3181 Input packages or derivations to the patching process. When this is
3182 @code{#f}, the usual set of inputs necessary for patching are provided,
3183 such as GNU@tie{}Patch.
3185 @item @code{modules} (default: @code{'()})
3186 A list of Guile modules that should be loaded during the patching
3187 process and while running the code in the @code{snippet} field.
3189 @item @code{patch-guile} (default: @code{#f})
3190 The Guile package that should be used in the patching process. When
3191 this is @code{#f}, a sensible default is used.
3197 @section Build Systems
3199 @cindex build system
3200 Each package definition specifies a @dfn{build system} and arguments for
3201 that build system (@pxref{Defining Packages}). This @code{build-system}
3202 field represents the build procedure of the package, as well as implicit
3203 dependencies of that build procedure.
3205 Build systems are @code{<build-system>} objects. The interface to
3206 create and manipulate them is provided by the @code{(guix build-system)}
3207 module, and actual build systems are exported by specific modules.
3209 @cindex bag (low-level package representation)
3210 Under the hood, build systems first compile package objects to
3211 @dfn{bags}. A @dfn{bag} is like a package, but with less
3212 ornamentation---in other words, a bag is a lower-level representation of
3213 a package, which includes all the inputs of that package, including some
3214 that were implicitly added by the build system. This intermediate
3215 representation is then compiled to a derivation (@pxref{Derivations}).
3217 Build systems accept an optional list of @dfn{arguments}. In package
3218 definitions, these are passed @i{via} the @code{arguments} field
3219 (@pxref{Defining Packages}). They are typically keyword arguments
3220 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3221 Guile Reference Manual}). The value of these arguments is usually
3222 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3223 by the daemon (@pxref{Derivations}).
3225 The main build system is @var{gnu-build-system}, which implements the
3226 standard build procedure for GNU and many other packages. It
3227 is provided by the @code{(guix build-system gnu)} module.
3229 @defvr {Scheme Variable} gnu-build-system
3230 @var{gnu-build-system} represents the GNU Build System, and variants
3231 thereof (@pxref{Configuration, configuration and makefile conventions,,
3232 standards, GNU Coding Standards}).
3234 @cindex build phases
3235 In a nutshell, packages using it are configured, built, and installed with
3236 the usual @code{./configure && make && make check && make install}
3237 command sequence. In practice, a few additional steps are often needed.
3238 All these steps are split up in separate @dfn{phases},
3239 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3240 modules for more details about the build phases.}:
3244 Unpack the source tarball, and change the current directory to the
3245 extracted source tree. If the source is actually a directory, copy it
3246 to the build tree, and enter that directory.
3248 @item patch-source-shebangs
3249 Patch shebangs encountered in source files so they refer to the right
3250 store file names. For instance, this changes @code{#!/bin/sh} to
3251 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3254 Run the @file{configure} script with a number of default options, such
3255 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3256 by the @code{#:configure-flags} argument.
3259 Run @code{make} with the list of flags specified with
3260 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3261 (the default), build with @code{make -j}.
3264 Run @code{make check}, or some other target specified with
3265 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3266 @code{#:parallel-tests?} argument is true (the default), run @code{make
3270 Run @code{make install} with the flags listed in @code{#:make-flags}.
3272 @item patch-shebangs
3273 Patch shebangs on the installed executable files.
3276 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3277 is false), copying them to the @code{debug} output when available
3278 (@pxref{Installing Debugging Files}).
3281 @vindex %standard-phases
3282 The build-side module @code{(guix build gnu-build-system)} defines
3283 @var{%standard-phases} as the default list of build phases.
3284 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3285 procedure implements the actual phase.
3287 The list of phases used for a particular package can be changed with the
3288 @code{#:phases} parameter. For instance, passing:
3291 #:phases (modify-phases %standard-phases (delete 'configure))
3294 means that all the phases described above will be used, except the
3295 @code{configure} phase.
3297 In addition, this build system ensures that the ``standard'' environment
3298 for GNU packages is available. This includes tools such as GCC, libc,
3299 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3300 build-system gnu)} module for a complete list). We call these the
3301 @dfn{implicit inputs} of a package, because package definitions do not
3302 have to mention them.
3305 Other @code{<build-system>} objects are defined to support other
3306 conventions and tools used by free software packages. They inherit most
3307 of @var{gnu-build-system}, and differ mainly in the set of inputs
3308 implicitly added to the build process, and in the list of phases
3309 executed. Some of these build systems are listed below.
3311 @defvr {Scheme Variable} ant-build-system
3312 This variable is exported by @code{(guix build-system ant)}. It
3313 implements the build procedure for Java packages that can be built with
3314 @url{http://ant.apache.org/, Ant build tool}.
3316 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3317 provided by the @code{icedtea} package to the set of inputs. Different
3318 packages can be specified with the @code{#:ant} and @code{#:jdk}
3319 parameters, respectively.
3321 When the original package does not provide a suitable Ant build file,
3322 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3323 build file @file{build.xml} with tasks to build the specified jar
3326 The parameter @code{#:build-target} can be used to specify the Ant task
3327 that should be run during the @code{build} phase. By default the
3328 ``jar'' task will be run.
3332 @defvr {Scheme Variable} asdf-build-system/source
3333 @defvrx {Scheme Variable} asdf-build-system/sbcl
3334 @defvrx {Scheme Variable} asdf-build-system/ecl
3336 These variables, exported by @code{(guix build-system asdf)}, implement
3337 build procedures for Common Lisp packages using
3338 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3339 definition facility for Common Lisp programs and libraries.
3341 The @code{asdf-build-system/source} system installs the packages in
3342 source form, and can be loaded using any common lisp implementation, via
3343 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3344 systems in the format which a particular implementation understands.
3345 These build systems can also be used to produce executable programs, or
3346 lisp images which contain a set of packages pre-loaded.
3348 The build system uses naming conventions. For binary packages, the
3349 package itself as well as its run-time dependencies should begin their
3350 name with the lisp implementation, such as @code{sbcl-} for
3351 @code{asdf-build-system/sbcl}. Beginning the input name with this
3352 prefix will allow the build system to encode its location into the
3353 resulting library, so that the input can be found at run-time.
3355 If dependencies are used only for tests, it is convenient to use a
3356 different prefix in order to avoid having a run-time dependency on such
3357 systems. For example,
3360 (define-public sbcl-bordeaux-threads
3363 (native-inputs `(("tests:cl-fiveam" ,sbcl-fiveam)))
3367 Additionally, the corresponding source package should be labeled using
3368 the same convention as python packages (see @ref{Python Modules}), using
3369 the @code{cl-} prefix.
3371 For binary packages, each system should be defined as a Guix package.
3372 If one package @code{origin} contains several systems, package variants
3373 can be created in order to build all the systems. Source packages,
3374 which use @code{asdf-build-system/source}, may contain several systems.
3376 In order to create executable programs and images, the build-side
3377 procedures @code{build-program} and @code{build-image} can be used.
3378 They should be called in a build phase after the @code{create-symlinks}
3379 phase, so that the system which was just built can be used within the
3380 resulting image. @code{build-program} requires a list of Common Lisp
3381 expressions to be passed as the @code{#:entry-program} argument.
3383 If the system is not defined within its own @code{.asd} file of the same
3384 name, then the @code{#:asd-file} parameter should be used to specify
3385 which file the system is defined in.
3389 @defvr {Scheme Variable} cargo-build-system
3390 @cindex Rust programming language
3391 @cindex Cargo (Rust build system)
3392 This variable is exported by @code{(guix build-system cargo)}. It
3393 supports builds of packages using Cargo, the build tool of the
3394 @uref{https://www.rust-lang.org, Rust programming language}.
3396 In its @code{configure} phase, this build system replaces dependencies
3397 specified in the @file{Carto.toml} file with inputs to the Guix package.
3398 The @code{install} phase installs the binaries, and it also installs the
3399 source code and @file{Cargo.toml} file.
3402 @defvr {Scheme Variable} cmake-build-system
3403 This variable is exported by @code{(guix build-system cmake)}. It
3404 implements the build procedure for packages using the
3405 @url{http://www.cmake.org, CMake build tool}.
3407 It automatically adds the @code{cmake} package to the set of inputs.
3408 Which package is used can be specified with the @code{#:cmake}
3411 The @code{#:configure-flags} parameter is taken as a list of flags
3412 passed to the @command{cmake} command. The @code{#:build-type}
3413 parameter specifies in abstract terms the flags passed to the compiler;
3414 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3415 debugging information''), which roughly means that code is compiled with
3416 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3419 @defvr {Scheme Variable} glib-or-gtk-build-system
3420 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3421 is intended for use with packages making use of GLib or GTK+.
3423 This build system adds the following two phases to the ones defined by
3424 @var{gnu-build-system}:
3427 @item glib-or-gtk-wrap
3428 The phase @code{glib-or-gtk-wrap} ensures that programs in
3429 @file{bin/} are able to find GLib ``schemas'' and
3430 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3431 modules}. This is achieved by wrapping the programs in launch scripts
3432 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3433 environment variables.
3435 It is possible to exclude specific package outputs from that wrapping
3436 process by listing their names in the
3437 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3438 when an output is known not to contain any GLib or GTK+ binaries, and
3439 where wrapping would gratuitously add a dependency of that output on
3442 @item glib-or-gtk-compile-schemas
3443 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3444 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3445 GSettings schemas} of GLib are compiled. Compilation is performed by the
3446 @command{glib-compile-schemas} program. It is provided by the package
3447 @code{glib:bin} which is automatically imported by the build system.
3448 The @code{glib} package providing @command{glib-compile-schemas} can be
3449 specified with the @code{#:glib} parameter.
3452 Both phases are executed after the @code{install} phase.
3455 @defvr {Scheme Variable} ocaml-build-system
3456 This variable is exported by @code{(guix build-system ocaml)}. It implements
3457 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3458 of choosing the correct set of commands to run for each package. OCaml
3459 packages can expect many different commands to be run. This build system will
3462 When the package has a @file{setup.ml} file present at the top-level, it will
3463 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3464 @code{ocaml setup.ml -install}. The build system will assume that this file
3465 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3466 care of setting the prefix and enabling tests if they are not disabled. You
3467 can pass configure and build flags with the @code{#:configure-flags} and
3468 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3469 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3470 bypass this system in the build and install phases.
3472 When the package has a @file{configure} file, it is assumed that it is a
3473 hand-made configure script that requires a different argument format than
3474 in the @code{gnu-build-system}. You can add more flags with the
3475 @code{#:configure-flags} key.
3477 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3478 @code{#t}), it will be used and more flags can be passed to the build and
3479 install phases with the @code{#:make-flags} key.
3481 Finally, some packages do not have these files and use a somewhat standard
3482 location for its build system. In that case, the build system will run
3483 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3484 providing the path to the required findlib module. Additional flags can
3485 be passed via the @code{#:build-flags} key. Install is taken care of by
3486 @command{opam-installer}. In this case, the @code{opam} package must
3487 be added to the @code{native-inputs} field of the package definition.
3489 Note that most OCaml packages assume they will be installed in the same
3490 directory as OCaml, which is not what we want in guix. In particular, they
3491 will install @file{.so} files in their module's directory, which is usually
3492 fine because it is in the OCaml compiler directory. In guix though, these
3493 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3494 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3495 @file{.so} libraries should be installed.
3498 @defvr {Scheme Variable} python-build-system
3499 This variable is exported by @code{(guix build-system python)}. It
3500 implements the more or less standard build procedure used by Python
3501 packages, which consists in running @code{python setup.py build} and
3502 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3504 For packages that install stand-alone Python programs under @code{bin/},
3505 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3506 environment variable points to all the Python libraries they depend on.
3508 Which Python package is used to perform the build can be specified with
3509 the @code{#:python} parameter. This is a useful way to force a package
3510 to be built for a specific version of the Python interpreter, which
3511 might be necessary if the package is only compatible with a single
3512 interpreter version.
3514 By default guix calls @code{setup.py} under control of
3515 @code{setuptools}, much like @command{pip} does. Some packages are not
3516 compatible with setuptools (and pip), thus you can disable this by
3517 setting the @code{#:use-setuptools} parameter to @code{#f}.
3520 @defvr {Scheme Variable} perl-build-system
3521 This variable is exported by @code{(guix build-system perl)}. It
3522 implements the standard build procedure for Perl packages, which either
3523 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3524 followed by @code{Build} and @code{Build install}; or in running
3525 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3526 @code{make} and @code{make install}, depending on which of
3527 @code{Build.PL} or @code{Makefile.PL} is present in the package
3528 distribution. Preference is given to the former if both @code{Build.PL}
3529 and @code{Makefile.PL} exist in the package distribution. This
3530 preference can be reversed by specifying @code{#t} for the
3531 @code{#:make-maker?} parameter.
3533 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3534 passes flags specified by the @code{#:make-maker-flags} or
3535 @code{#:module-build-flags} parameter, respectively.
3537 Which Perl package is used can be specified with @code{#:perl}.
3540 @defvr {Scheme Variable} r-build-system
3541 This variable is exported by @code{(guix build-system r)}. It
3542 implements the build procedure used by @uref{http://r-project.org, R}
3543 packages, which essentially is little more than running @code{R CMD
3544 INSTALL --library=/gnu/store/@dots{}} in an environment where
3545 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3546 are run after installation using the R function
3547 @code{tools::testInstalledPackage}.
3550 @defvr {Scheme Variable} ruby-build-system
3551 This variable is exported by @code{(guix build-system ruby)}. It
3552 implements the RubyGems build procedure used by Ruby packages, which
3553 involves running @code{gem build} followed by @code{gem install}.
3555 The @code{source} field of a package that uses this build system
3556 typically references a gem archive, since this is the format that Ruby
3557 developers use when releasing their software. The build system unpacks
3558 the gem archive, potentially patches the source, runs the test suite,
3559 repackages the gem, and installs it. Additionally, directories and
3560 tarballs may be referenced to allow building unreleased gems from Git or
3561 a traditional source release tarball.
3563 Which Ruby package is used can be specified with the @code{#:ruby}
3564 parameter. A list of additional flags to be passed to the @command{gem}
3565 command can be specified with the @code{#:gem-flags} parameter.
3568 @defvr {Scheme Variable} waf-build-system
3569 This variable is exported by @code{(guix build-system waf)}. It
3570 implements a build procedure around the @code{waf} script. The common
3571 phases---@code{configure}, @code{build}, and @code{install}---are
3572 implemented by passing their names as arguments to the @code{waf}
3575 The @code{waf} script is executed by the Python interpreter. Which
3576 Python package is used to run the script can be specified with the
3577 @code{#:python} parameter.
3580 @defvr {Scheme Variable} haskell-build-system
3581 This variable is exported by @code{(guix build-system haskell)}. It
3582 implements the Cabal build procedure used by Haskell packages, which
3583 involves running @code{runhaskell Setup.hs configure
3584 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3585 Instead of installing the package by running @code{runhaskell Setup.hs
3586 install}, to avoid trying to register libraries in the read-only
3587 compiler store directory, the build system uses @code{runhaskell
3588 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3589 addition, the build system generates the package documentation by
3590 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3591 is passed. Optional Haddock parameters can be passed with the help of
3592 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3593 not found, the build system looks for @code{Setup.lhs} instead.
3595 Which Haskell compiler is used can be specified with the @code{#:haskell}
3596 parameter which defaults to @code{ghc}.
3599 @defvr {Scheme Variable} dub-build-system
3600 This variable is exported by @code{(guix build-system dub)}. It
3601 implements the Dub build procedure used by D packages, which
3602 involves running @code{dub build} and @code{dub run}.
3603 Installation is done by copying the files manually.
3605 Which D compiler is used can be specified with the @code{#:ldc}
3606 parameter which defaults to @code{ldc}.
3609 @defvr {Scheme Variable} emacs-build-system
3610 This variable is exported by @code{(guix build-system emacs)}. It
3611 implements an installation procedure similar to the packaging system
3612 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3614 It first creates the @code{@var{package}-autoloads.el} file, then it
3615 byte compiles all Emacs Lisp files. Differently from the Emacs
3616 packaging system, the Info documentation files are moved to the standard
3617 documentation directory and the @file{dir} file is deleted. Each
3618 package is installed in its own directory under
3619 @file{share/emacs/site-lisp/guix.d}.
3622 Lastly, for packages that do not need anything as sophisticated, a
3623 ``trivial'' build system is provided. It is trivial in the sense that
3624 it provides basically no support: it does not pull any implicit inputs,
3625 and does not have a notion of build phases.
3627 @defvr {Scheme Variable} trivial-build-system
3628 This variable is exported by @code{(guix build-system trivial)}.
3630 This build system requires a @code{#:builder} argument. This argument
3631 must be a Scheme expression that builds the package output(s)---as
3632 with @code{build-expression->derivation} (@pxref{Derivations,
3633 @code{build-expression->derivation}}).
3643 Conceptually, the @dfn{store} is the place where derivations that have
3644 been built successfully are stored---by default, @file{/gnu/store}.
3645 Sub-directories in the store are referred to as @dfn{store items} or
3646 sometimes @dfn{store paths}. The store has an associated database that
3647 contains information such as the store paths referred to by each store
3648 path, and the list of @emph{valid} store items---results of successful
3649 builds. This database resides in @file{@var{localstatedir}/guix/db},
3650 where @var{localstatedir} is the state directory specified @i{via}
3651 @option{--localstatedir} at configure time, usually @file{/var}.
3653 The store is @emph{always} accessed by the daemon on behalf of its clients
3654 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3655 connect to the daemon over a Unix-domain socket, send requests to it,
3656 and read the result---these are remote procedure calls, or RPCs.
3659 Users must @emph{never} modify files under @file{/gnu/store} directly.
3660 This would lead to inconsistencies and break the immutability
3661 assumptions of Guix's functional model (@pxref{Introduction}).
3663 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3664 how to check the integrity of the store and attempt recovery from
3665 accidental modifications.
3668 The @code{(guix store)} module provides procedures to connect to the
3669 daemon, and to perform RPCs. These are described below.
3671 @deffn {Scheme Procedure} open-connection [@var{file}] [#:reserve-space? #t]
3672 Connect to the daemon over the Unix-domain socket at @var{file}. When
3673 @var{reserve-space?} is true, instruct it to reserve a little bit of
3674 extra space on the file system so that the garbage collector can still
3675 operate should the disk become full. Return a server object.
3677 @var{file} defaults to @var{%default-socket-path}, which is the normal
3678 location given the options that were passed to @command{configure}.
3681 @deffn {Scheme Procedure} close-connection @var{server}
3682 Close the connection to @var{server}.
3685 @defvr {Scheme Variable} current-build-output-port
3686 This variable is bound to a SRFI-39 parameter, which refers to the port
3687 where build and error logs sent by the daemon should be written.
3690 Procedures that make RPCs all take a server object as their first
3693 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3694 @cindex invalid store items
3695 Return @code{#t} when @var{path} designates a valid store item and
3696 @code{#f} otherwise (an invalid item may exist on disk but still be
3697 invalid, for instance because it is the result of an aborted or failed
3700 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3701 prefixed by the store directory (@file{/gnu/store}).
3704 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3705 Add @var{text} under file @var{name} in the store, and return its store
3706 path. @var{references} is the list of store paths referred to by the
3707 resulting store path.
3710 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3711 Build @var{derivations} (a list of @code{<derivation>} objects or
3712 derivation paths), and return when the worker is done building them.
3713 Return @code{#t} on success.
3716 Note that the @code{(guix monads)} module provides a monad as well as
3717 monadic versions of the above procedures, with the goal of making it
3718 more convenient to work with code that accesses the store (@pxref{The
3722 @i{This section is currently incomplete.}
3725 @section Derivations
3728 Low-level build actions and the environment in which they are performed
3729 are represented by @dfn{derivations}. A derivation contains the
3730 following pieces of information:
3734 The outputs of the derivation---derivations produce at least one file or
3735 directory in the store, but may produce more.
3738 The inputs of the derivations, which may be other derivations or plain
3739 files in the store (patches, build scripts, etc.)
3742 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3745 The file name of a build script in the store, along with the arguments
3749 A list of environment variables to be defined.
3753 @cindex derivation path
3754 Derivations allow clients of the daemon to communicate build actions to
3755 the store. They exist in two forms: as an in-memory representation,
3756 both on the client- and daemon-side, and as files in the store whose
3757 name end in @code{.drv}---these files are referred to as @dfn{derivation
3758 paths}. Derivations paths can be passed to the @code{build-derivations}
3759 procedure to perform the build actions they prescribe (@pxref{The
3762 The @code{(guix derivations)} module provides a representation of
3763 derivations as Scheme objects, along with procedures to create and
3764 otherwise manipulate derivations. The lowest-level primitive to create
3765 a derivation is the @code{derivation} procedure:
3767 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3768 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3769 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3770 [#:system (%current-system)] [#:references-graphs #f] @
3771 [#:allowed-references #f] [#:disallowed-references #f] @
3772 [#:leaked-env-vars #f] [#:local-build? #f] @
3773 [#:substitutable? #t]
3774 Build a derivation with the given arguments, and return the resulting
3775 @code{<derivation>} object.
3777 When @var{hash} and @var{hash-algo} are given, a
3778 @dfn{fixed-output derivation} is created---i.e., one whose result is
3779 known in advance, such as a file download. If, in addition,
3780 @var{recursive?} is true, then that fixed output may be an executable
3781 file or a directory and @var{hash} must be the hash of an archive
3782 containing this output.
3784 When @var{references-graphs} is true, it must be a list of file
3785 name/store path pairs. In that case, the reference graph of each store
3786 path is exported in the build environment in the corresponding file, in
3787 a simple text format.
3789 When @var{allowed-references} is true, it must be a list of store items
3790 or outputs that the derivation's output may refer to. Likewise,
3791 @var{disallowed-references}, if true, must be a list of things the
3792 outputs may @emph{not} refer to.
3794 When @var{leaked-env-vars} is true, it must be a list of strings
3795 denoting environment variables that are allowed to ``leak'' from the
3796 daemon's environment to the build environment. This is only applicable
3797 to fixed-output derivations---i.e., when @var{hash} is true. The main
3798 use is to allow variables such as @code{http_proxy} to be passed to
3799 derivations that download files.
3801 When @var{local-build?} is true, declare that the derivation is not a
3802 good candidate for offloading and should rather be built locally
3803 (@pxref{Daemon Offload Setup}). This is the case for small derivations
3804 where the costs of data transfers would outweigh the benefits.
3806 When @var{substitutable?} is false, declare that substitutes of the
3807 derivation's output should not be used (@pxref{Substitutes}). This is
3808 useful, for instance, when building packages that capture details of the
3809 host CPU instruction set.
3813 Here's an example with a shell script as its builder, assuming
3814 @var{store} is an open connection to the daemon, and @var{bash} points
3815 to a Bash executable in the store:
3818 (use-modules (guix utils)
3822 (let ((builder ; add the Bash script to the store
3823 (add-text-to-store store "my-builder.sh"
3824 "echo hello world > $out\n" '())))
3825 (derivation store "foo"
3826 bash `("-e" ,builder)
3827 #:inputs `((,bash) (,builder))
3828 #:env-vars '(("HOME" . "/homeless"))))
3829 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
3832 As can be guessed, this primitive is cumbersome to use directly. A
3833 better approach is to write build scripts in Scheme, of course! The
3834 best course of action for that is to write the build code as a
3835 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
3836 information, @pxref{G-Expressions}.
3838 Once upon a time, @code{gexp->derivation} did not exist and constructing
3839 derivations with build code written in Scheme was achieved with
3840 @code{build-expression->derivation}, documented below. This procedure
3841 is now deprecated in favor of the much nicer @code{gexp->derivation}.
3843 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
3844 @var{name} @var{exp} @
3845 [#:system (%current-system)] [#:inputs '()] @
3846 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3847 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3848 [#:references-graphs #f] [#:allowed-references #f] @
3849 [#:disallowed-references #f] @
3850 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3851 Return a derivation that executes Scheme expression @var{exp} as a
3852 builder for derivation @var{name}. @var{inputs} must be a list of
3853 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
3854 @code{"out"} is assumed. @var{modules} is a list of names of Guile
3855 modules from the current search path to be copied in the store,
3856 compiled, and made available in the load path during the execution of
3857 @var{exp}---e.g., @code{((guix build utils) (guix build
3858 gnu-build-system))}.
3860 @var{exp} is evaluated in an environment where @code{%outputs} is bound
3861 to a list of output/path pairs, and where @code{%build-inputs} is bound
3862 to a list of string/output-path pairs made from @var{inputs}.
3863 Optionally, @var{env-vars} is a list of string pairs specifying the name
3864 and value of environment variables visible to the builder. The builder
3865 terminates by passing the result of @var{exp} to @code{exit}; thus, when
3866 @var{exp} returns @code{#f}, the build is considered to have failed.
3868 @var{exp} is built using @var{guile-for-build} (a derivation). When
3869 @var{guile-for-build} is omitted or is @code{#f}, the value of the
3870 @code{%guile-for-build} fluid is used instead.
3872 See the @code{derivation} procedure for the meaning of
3873 @var{references-graphs}, @var{allowed-references},
3874 @var{disallowed-references}, @var{local-build?}, and
3875 @var{substitutable?}.
3879 Here's an example of a single-output derivation that creates a directory
3880 containing one file:
3883 (let ((builder '(let ((out (assoc-ref %outputs "out")))
3884 (mkdir out) ; create /gnu/store/@dots{}-goo
3885 (call-with-output-file (string-append out "/test")
3887 (display '(hello guix) p))))))
3888 (build-expression->derivation store "goo" builder))
3890 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
3894 @node The Store Monad
3895 @section The Store Monad
3899 The procedures that operate on the store described in the previous
3900 sections all take an open connection to the build daemon as their first
3901 argument. Although the underlying model is functional, they either have
3902 side effects or depend on the current state of the store.
3904 The former is inconvenient: the connection to the build daemon has to be
3905 carried around in all those functions, making it impossible to compose
3906 functions that do not take that parameter with functions that do. The
3907 latter can be problematic: since store operations have side effects
3908 and/or depend on external state, they have to be properly sequenced.
3910 @cindex monadic values
3911 @cindex monadic functions
3912 This is where the @code{(guix monads)} module comes in. This module
3913 provides a framework for working with @dfn{monads}, and a particularly
3914 useful monad for our uses, the @dfn{store monad}. Monads are a
3915 construct that allows two things: associating ``context'' with values
3916 (in our case, the context is the store), and building sequences of
3917 computations (here computations include accesses to the store). Values
3918 in a monad---values that carry this additional context---are called
3919 @dfn{monadic values}; procedures that return such values are called
3920 @dfn{monadic procedures}.
3922 Consider this ``normal'' procedure:
3925 (define (sh-symlink store)
3926 ;; Return a derivation that symlinks the 'bash' executable.
3927 (let* ((drv (package-derivation store bash))
3928 (out (derivation->output-path drv))
3929 (sh (string-append out "/bin/bash")))
3930 (build-expression->derivation store "sh"
3931 `(symlink ,sh %output))))
3934 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
3935 as a monadic function:
3938 (define (sh-symlink)
3939 ;; Same, but return a monadic value.
3940 (mlet %store-monad ((drv (package->derivation bash)))
3941 (gexp->derivation "sh"
3942 #~(symlink (string-append #$drv "/bin/bash")
3946 There are several things to note in the second version: the @code{store}
3947 parameter is now implicit and is ``threaded'' in the calls to the
3948 @code{package->derivation} and @code{gexp->derivation} monadic
3949 procedures, and the monadic value returned by @code{package->derivation}
3950 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
3952 As it turns out, the call to @code{package->derivation} can even be
3953 omitted since it will take place implicitly, as we will see later
3954 (@pxref{G-Expressions}):
3957 (define (sh-symlink)
3958 (gexp->derivation "sh"
3959 #~(symlink (string-append #$bash "/bin/bash")
3964 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
3965 @c for the funny quote.
3966 Calling the monadic @code{sh-symlink} has no effect. As someone once
3967 said, ``you exit a monad like you exit a building on fire: by running''.
3968 So, to exit the monad and get the desired effect, one must use
3969 @code{run-with-store}:
3972 (run-with-store (open-connection) (sh-symlink))
3973 @result{} /gnu/store/...-sh-symlink
3976 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
3977 new ``meta-commands'' to make it easier to deal with monadic procedures:
3978 @code{run-in-store}, and @code{enter-store-monad}. The former is used
3979 to ``run'' a single monadic value through the store:
3982 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
3983 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
3986 The latter enters a recursive REPL, where all the return values are
3987 automatically run through the store:
3990 scheme@@(guile-user)> ,enter-store-monad
3991 store-monad@@(guile-user) [1]> (package->derivation hello)
3992 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
3993 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
3994 $3 = "/gnu/store/@dots{}-foo"
3995 store-monad@@(guile-user) [1]> ,q
3996 scheme@@(guile-user)>
4000 Note that non-monadic values cannot be returned in the
4001 @code{store-monad} REPL.
4003 The main syntactic forms to deal with monads in general are provided by
4004 the @code{(guix monads)} module and are described below.
4006 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4007 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4011 @deffn {Scheme Syntax} return @var{val}
4012 Return a monadic value that encapsulates @var{val}.
4015 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4016 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4017 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4018 referred to as ``bind'', but that name denotes an unrelated procedure in
4019 Guile. Thus we use this somewhat cryptic symbol inherited from the
4020 Haskell language.}. There can be one @var{mproc} or several of them, as
4025 (with-monad %state-monad
4027 (lambda (x) (return (+ 1 x)))
4028 (lambda (x) (return (* 2 x)))))
4032 @result{} some-state
4036 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4038 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4040 Bind the variables @var{var} to the monadic values @var{mval} in
4041 @var{body}, which is a sequence of expressions. As with the bind
4042 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4043 value ``contained'' in @var{mval} and making @var{var} refer to that
4044 raw, non-monadic value within the scope of the @var{body}. The form
4045 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4046 @var{val}, as per @code{let}. The binding operations occur in sequence
4047 from left to right. The last expression of @var{body} must be a monadic
4048 expression, and its result will become the result of the @code{mlet} or
4049 @code{mlet*} when run in the @var{monad}.
4051 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4052 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4055 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4056 Bind @var{mexp} and the following monadic expressions in sequence,
4057 returning the result of the last expression. Every expression in the
4058 sequence must be a monadic expression.
4060 This is akin to @code{mlet}, except that the return values of the
4061 monadic expressions are ignored. In that sense, it is analogous to
4062 @code{begin}, but applied to monadic expressions.
4065 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4066 When @var{condition} is true, evaluate the sequence of monadic
4067 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4068 @var{condition} is false, return @code{*unspecified*} in the current
4069 monad. Every expression in the sequence must be a monadic expression.
4072 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4073 When @var{condition} is false, evaluate the sequence of monadic
4074 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4075 @var{condition} is true, return @code{*unspecified*} in the current
4076 monad. Every expression in the sequence must be a monadic expression.
4080 The @code{(guix monads)} module provides the @dfn{state monad}, which
4081 allows an additional value---the state---to be @emph{threaded} through
4082 monadic procedure calls.
4084 @defvr {Scheme Variable} %state-monad
4085 The state monad. Procedures in the state monad can access and change
4086 the state that is threaded.
4088 Consider the example below. The @code{square} procedure returns a value
4089 in the state monad. It returns the square of its argument, but also
4090 increments the current state value:
4094 (mlet %state-monad ((count (current-state)))
4095 (mbegin %state-monad
4096 (set-current-state (+ 1 count))
4099 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4104 When ``run'' through @var{%state-monad}, we obtain that additional state
4105 value, which is the number of @code{square} calls.
4108 @deffn {Monadic Procedure} current-state
4109 Return the current state as a monadic value.
4112 @deffn {Monadic Procedure} set-current-state @var{value}
4113 Set the current state to @var{value} and return the previous state as a
4117 @deffn {Monadic Procedure} state-push @var{value}
4118 Push @var{value} to the current state, which is assumed to be a list,
4119 and return the previous state as a monadic value.
4122 @deffn {Monadic Procedure} state-pop
4123 Pop a value from the current state and return it as a monadic value.
4124 The state is assumed to be a list.
4127 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4128 Run monadic value @var{mval} starting with @var{state} as the initial
4129 state. Return two values: the resulting value, and the resulting state.
4132 The main interface to the store monad, provided by the @code{(guix
4133 store)} module, is as follows.
4135 @defvr {Scheme Variable} %store-monad
4136 The store monad---an alias for @var{%state-monad}.
4138 Values in the store monad encapsulate accesses to the store. When its
4139 effect is needed, a value of the store monad must be ``evaluated'' by
4140 passing it to the @code{run-with-store} procedure (see below.)
4143 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4144 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4145 open store connection.
4148 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4149 Return as a monadic value the absolute file name in the store of the file
4150 containing @var{text}, a string. @var{references} is a list of store items that the
4151 resulting text file refers to; it defaults to the empty list.
4154 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4155 [#:recursive? #t] [#:select? (const #t)]
4156 Return the name of @var{file} once interned in the store. Use
4157 @var{name} as its store name, or the basename of @var{file} if
4158 @var{name} is omitted.
4160 When @var{recursive?} is true, the contents of @var{file} are added
4161 recursively; if @var{file} designates a flat file and @var{recursive?}
4162 is true, its contents are added, and its permission bits are kept.
4164 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4165 @var{stat})} for each directory entry, where @var{file} is the entry's
4166 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4167 entries for which @var{select?} does not return true.
4169 The example below adds a file to the store, under two different names:
4172 (run-with-store (open-connection)
4173 (mlet %store-monad ((a (interned-file "README"))
4174 (b (interned-file "README" "LEGU-MIN")))
4175 (return (list a b))))
4177 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4182 The @code{(guix packages)} module exports the following package-related
4185 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4186 [#:system (%current-system)] [#:target #f] @
4189 value in the absolute file name of @var{file} within the @var{output}
4190 directory of @var{package}. When @var{file} is omitted, return the name
4191 of the @var{output} directory of @var{package}. When @var{target} is
4192 true, use it as a cross-compilation target triplet.
4195 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4196 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4197 @var{target} [@var{system}]
4198 Monadic version of @code{package-derivation} and
4199 @code{package-cross-derivation} (@pxref{Defining Packages}).
4204 @section G-Expressions
4206 @cindex G-expression
4207 @cindex build code quoting
4208 So we have ``derivations'', which represent a sequence of build actions
4209 to be performed to produce an item in the store (@pxref{Derivations}).
4210 These build actions are performed when asking the daemon to actually
4211 build the derivations; they are run by the daemon in a container
4212 (@pxref{Invoking guix-daemon}).
4214 @cindex strata of code
4215 It should come as no surprise that we like to write these build actions
4216 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4217 code@footnote{The term @dfn{stratum} in this context was coined by
4218 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4219 Kiselyov, who has written insightful
4220 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4221 on this topic}, refers to this kind of code generation as
4222 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4223 to the daemon, etc.---and the ``build code''---code that actually
4224 performs build actions, such as making directories, invoking
4225 @command{make}, etc.
4227 To describe a derivation and its build actions, one typically needs to
4228 embed build code inside host code. It boils down to manipulating build
4229 code as data, and the homoiconicity of Scheme---code has a direct
4230 representation as data---comes in handy for that. But we need more than
4231 the normal @code{quasiquote} mechanism in Scheme to construct build
4234 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4235 S-expressions adapted to build expressions. G-expressions, or
4236 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4237 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4238 @code{#$}, and @code{#$@@}), which are comparable to
4239 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4240 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4241 GNU Guile Reference Manual}). However, there are major differences:
4245 Gexps are meant to be written to a file and run or manipulated by other
4249 When a high-level object such as a package or derivation is unquoted
4250 inside a gexp, the result is as if its output file name had been
4254 Gexps carry information about the packages or derivations they refer to,
4255 and these dependencies are automatically added as inputs to the build
4256 processes that use them.
4259 @cindex lowering, of high-level objects in gexps
4260 This mechanism is not limited to package and derivation
4261 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4262 derivations or files in the store can be defined,
4263 such that these objects can also be inserted
4264 into gexps. For example, a useful type of high-level objects that can be
4265 inserted in a gexp is ``file-like objects'', which make it easy to
4266 add files to the store and to refer to them in
4267 derivations and such (see @code{local-file} and @code{plain-file}
4270 To illustrate the idea, here is an example of a gexp:
4277 (symlink (string-append #$coreutils "/bin/ls")
4281 This gexp can be passed to @code{gexp->derivation}; we obtain a
4282 derivation that builds a directory containing exactly one symlink to
4283 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4286 (gexp->derivation "the-thing" build-exp)
4289 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4290 substituted to the reference to the @var{coreutils} package in the
4291 actual build code, and @var{coreutils} is automatically made an input to
4292 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4293 output)}) is replaced by a string containing the directory name of the
4294 output of the derivation.
4296 @cindex cross compilation
4297 In a cross-compilation context, it is useful to distinguish between
4298 references to the @emph{native} build of a package---that can run on the
4299 host---versus references to cross builds of a package. To that end, the
4300 @code{#+} plays the same role as @code{#$}, but is a reference to a
4301 native package build:
4304 (gexp->derivation "vi"
4307 (system* (string-append #+coreutils "/bin/ln")
4309 (string-append #$emacs "/bin/emacs")
4310 (string-append #$output "/bin/vi")))
4311 #:target "mips64el-linux-gnu")
4315 In the example above, the native build of @var{coreutils} is used, so
4316 that @command{ln} can actually run on the host; but then the
4317 cross-compiled build of @var{emacs} is referenced.
4319 @cindex imported modules, for gexps
4320 @findex with-imported-modules
4321 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4322 able to use certain Guile modules from the ``host environment'' in the
4323 gexp, so those modules should be imported in the ``build environment''.
4324 The @code{with-imported-modules} form allows you to express that:
4327 (let ((build (with-imported-modules '((guix build utils))
4329 (use-modules (guix build utils))
4330 (mkdir-p (string-append #$output "/bin"))))))
4331 (gexp->derivation "empty-dir"
4334 (display "success!\n")
4339 In this example, the @code{(guix build utils)} module is automatically
4340 pulled into the isolated build environment of our gexp, such that
4341 @code{(use-modules (guix build utils))} works as expected.
4343 @cindex module closure
4344 @findex source-module-closure
4345 Usually you want the @emph{closure} of the module to be imported---i.e.,
4346 the module itself and all the modules it depends on---rather than just
4347 the module; failing to do that, attempts to use the module will fail
4348 because of missing dependent modules. The @code{source-module-closure}
4349 procedure computes the closure of a module by looking at its source file
4350 headers, which comes in handy in this case:
4353 (use-modules (guix modules)) ;for 'source-module-closure'
4355 (with-imported-modules (source-module-closure
4356 '((guix build utils)
4358 (gexp->derivation "something-with-vms"
4360 (use-modules (guix build utils)
4365 The syntactic form to construct gexps is summarized below.
4367 @deffn {Scheme Syntax} #~@var{exp}
4368 @deffnx {Scheme Syntax} (gexp @var{exp})
4369 Return a G-expression containing @var{exp}. @var{exp} may contain one
4370 or more of the following forms:
4374 @itemx (ungexp @var{obj})
4375 Introduce a reference to @var{obj}. @var{obj} may have one of the
4376 supported types, for example a package or a
4377 derivation, in which case the @code{ungexp} form is replaced by its
4378 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4380 If @var{obj} is a list, it is traversed and references to supported
4381 objects are substituted similarly.
4383 If @var{obj} is another gexp, its contents are inserted and its
4384 dependencies are added to those of the containing gexp.
4386 If @var{obj} is another kind of object, it is inserted as is.
4388 @item #$@var{obj}:@var{output}
4389 @itemx (ungexp @var{obj} @var{output})
4390 This is like the form above, but referring explicitly to the
4391 @var{output} of @var{obj}---this is useful when @var{obj} produces
4392 multiple outputs (@pxref{Packages with Multiple Outputs}).
4395 @itemx #+@var{obj}:output
4396 @itemx (ungexp-native @var{obj})
4397 @itemx (ungexp-native @var{obj} @var{output})
4398 Same as @code{ungexp}, but produces a reference to the @emph{native}
4399 build of @var{obj} when used in a cross compilation context.
4401 @item #$output[:@var{output}]
4402 @itemx (ungexp output [@var{output}])
4403 Insert a reference to derivation output @var{output}, or to the main
4404 output when @var{output} is omitted.
4406 This only makes sense for gexps passed to @code{gexp->derivation}.
4409 @itemx (ungexp-splicing @var{lst})
4410 Like the above, but splices the contents of @var{lst} inside the
4414 @itemx (ungexp-native-splicing @var{lst})
4415 Like the above, but refers to native builds of the objects listed in
4420 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4421 of the @code{gexp?} type (see below.)
4424 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4425 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4426 in their execution environment.
4428 Each item in @var{modules} can be the name of a module, such as
4429 @code{(guix build utils)}, or it can be a module name, followed by an
4430 arrow, followed by a file-like object:
4433 `((guix build utils)
4435 ((guix config) => ,(scheme-file "config.scm"
4436 #~(define-module @dots{}))))
4440 In the example above, the first two modules are taken from the search
4441 path, and the last one is created from the given file-like object.
4443 This form has @emph{lexical} scope: it has an effect on the gexps
4444 directly defined in @var{body}@dots{}, but not on those defined, say, in
4445 procedures called from @var{body}@dots{}.
4448 @deffn {Scheme Procedure} gexp? @var{obj}
4449 Return @code{#t} if @var{obj} is a G-expression.
4452 G-expressions are meant to be written to disk, either as code building
4453 some derivation, or as plain files in the store. The monadic procedures
4454 below allow you to do that (@pxref{The Store Monad}, for more
4455 information about monads.)
4457 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4458 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4459 [#:hash #f] [#:hash-algo #f] @
4460 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4461 [#:module-path @var{%load-path}] @
4462 [#:references-graphs #f] [#:allowed-references #f] @
4463 [#:disallowed-references #f] @
4464 [#:leaked-env-vars #f] @
4465 [#:script-name (string-append @var{name} "-builder")] @
4466 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4467 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4468 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4469 stored in a file called @var{script-name}. When @var{target} is true,
4470 it is used as the cross-compilation target triplet for packages referred
4473 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4475 make @var{modules} available in the evaluation context of @var{exp};
4476 @var{modules} is a list of names of Guile modules searched in
4477 @var{module-path} to be copied in the store, compiled, and made available in
4478 the load path during the execution of @var{exp}---e.g., @code{((guix
4479 build utils) (guix build gnu-build-system))}.
4481 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4484 When @var{references-graphs} is true, it must be a list of tuples of one of the
4488 (@var{file-name} @var{package})
4489 (@var{file-name} @var{package} @var{output})
4490 (@var{file-name} @var{derivation})
4491 (@var{file-name} @var{derivation} @var{output})
4492 (@var{file-name} @var{store-item})
4495 The right-hand-side of each element of @var{references-graphs} is automatically made
4496 an input of the build process of @var{exp}. In the build environment, each
4497 @var{file-name} contains the reference graph of the corresponding item, in a simple
4500 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4501 In the latter case, the list denotes store items that the result is allowed to
4502 refer to. Any reference to another store item will lead to a build error.
4503 Similarly for @var{disallowed-references}, which can list items that must not be
4504 referenced by the outputs.
4506 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4509 @cindex file-like objects
4510 The @code{local-file}, @code{plain-file}, @code{computed-file},
4511 @code{program-file}, and @code{scheme-file} procedures below return
4512 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4513 these objects lead to a file in the store. Consider this G-expression:
4516 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4517 #$(local-file "/tmp/my-nscd.conf"))
4520 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4521 to the store. Once expanded, for instance @i{via}
4522 @code{gexp->derivation}, the G-expression refers to that copy under
4523 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4524 does not have any effect on what the G-expression does.
4525 @code{plain-file} can be used similarly; it differs in that the file
4526 content is directly passed as a string.
4528 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4529 [#:recursive? #f] [#:select? (const #t)]
4530 Return an object representing local file @var{file} to add to the store; this
4531 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4532 up relative to the source file where this form appears. @var{file} will be added to
4533 the store under @var{name}--by default the base name of @var{file}.
4535 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4536 designates a flat file and @var{recursive?} is true, its contents are added, and its
4537 permission bits are kept.
4539 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4540 @var{stat})} for each directory entry, where @var{file} is the entry's
4541 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4542 entries for which @var{select?} does not return true.
4544 This is the declarative counterpart of the @code{interned-file} monadic
4545 procedure (@pxref{The Store Monad, @code{interned-file}}).
4548 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4549 Return an object representing a text file called @var{name} with the given
4550 @var{content} (a string) to be added to the store.
4552 This is the declarative counterpart of @code{text-file}.
4555 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4556 [#:options '(#:local-build? #t)]
4557 Return an object representing the store item @var{name}, a file or
4558 directory computed by @var{gexp}. @var{options}
4559 is a list of additional arguments to pass to @code{gexp->derivation}.
4561 This is the declarative counterpart of @code{gexp->derivation}.
4564 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4565 Return an executable script @var{name} that runs @var{exp} using
4566 @var{guile}, with @var{exp}'s imported modules in its search path.
4568 The example below builds a script that simply invokes the @command{ls}
4572 (use-modules (guix gexp) (gnu packages base))
4574 (gexp->script "list-files"
4575 #~(execl #$(file-append coreutils "/bin/ls")
4579 When ``running'' it through the store (@pxref{The Store Monad,
4580 @code{run-with-store}}), we obtain a derivation that produces an
4581 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4584 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4586 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4590 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4592 Return an object representing the executable store item @var{name} that
4593 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4596 This is the declarative counterpart of @code{gexp->script}.
4599 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4600 [#:set-load-path? #t]
4601 Return a derivation that builds a file @var{name} containing @var{exp}.
4602 When @var{set-load-path?} is true, emit code in the resulting file to
4603 set @code{%load-path} and @code{%load-compiled-path} to honor
4604 @var{exp}'s imported modules.
4606 The resulting file holds references to all the dependencies of @var{exp}
4607 or a subset thereof.
4610 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4611 Return an object representing the Scheme file @var{name} that contains
4614 This is the declarative counterpart of @code{gexp->file}.
4617 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4618 Return as a monadic value a derivation that builds a text file
4619 containing all of @var{text}. @var{text} may list, in addition to
4620 strings, objects of any type that can be used in a gexp: packages,
4621 derivations, local file objects, etc. The resulting store file holds
4622 references to all these.
4624 This variant should be preferred over @code{text-file} anytime the file
4625 to create will reference items from the store. This is typically the
4626 case when building a configuration file that embeds store file names,
4630 (define (profile.sh)
4631 ;; Return the name of a shell script in the store that
4632 ;; initializes the 'PATH' environment variable.
4633 (text-file* "profile.sh"
4634 "export PATH=" coreutils "/bin:"
4635 grep "/bin:" sed "/bin\n"))
4638 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4639 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4640 preventing them from being garbage-collected during its lifetime.
4643 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4644 Return an object representing store file @var{name} containing
4645 @var{text}. @var{text} is a sequence of strings and file-like objects,
4649 (mixed-text-file "profile"
4650 "export PATH=" coreutils "/bin:" grep "/bin")
4653 This is the declarative counterpart of @code{text-file*}.
4656 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4657 Return a file-like object that expands to the concatenation of @var{obj}
4658 and @var{suffix}, where @var{obj} is a lowerable object and each
4659 @var{suffix} is a string.
4661 As an example, consider this gexp:
4664 (gexp->script "run-uname"
4665 #~(system* #$(file-append coreutils
4669 The same effect could be achieved with:
4672 (gexp->script "run-uname"
4673 #~(system* (string-append #$coreutils
4677 There is one difference though: in the @code{file-append} case, the
4678 resulting script contains the absolute file name as a string, whereas in
4679 the second case, the resulting script contains a @code{(string-append
4680 @dots{})} expression to construct the file name @emph{at run time}.
4684 Of course, in addition to gexps embedded in ``host'' code, there are
4685 also modules containing build tools. To make it clear that they are
4686 meant to be used in the build stratum, these modules are kept in the
4687 @code{(guix build @dots{})} name space.
4689 @cindex lowering, of high-level objects in gexps
4690 Internally, high-level objects are @dfn{lowered}, using their compiler,
4691 to either derivations or store items. For instance, lowering a package
4692 yields a derivation, and lowering a @code{plain-file} yields a store
4693 item. This is achieved using the @code{lower-object} monadic procedure.
4695 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4697 Return as a value in @var{%store-monad} the derivation or store item
4698 corresponding to @var{obj} for @var{system}, cross-compiling for
4699 @var{target} if @var{target} is true. @var{obj} must be an object that
4700 has an associated gexp compiler, such as a @code{<package>}.
4704 @c *********************************************************************
4708 This section describes Guix command-line utilities. Some of them are
4709 primarily targeted at developers and users who write new package
4710 definitions, while others are more generally useful. They complement
4711 the Scheme programming interface of Guix in a convenient way.
4714 * Invoking guix build:: Building packages from the command line.
4715 * Invoking guix edit:: Editing package definitions.
4716 * Invoking guix download:: Downloading a file and printing its hash.
4717 * Invoking guix hash:: Computing the cryptographic hash of a file.
4718 * Invoking guix import:: Importing package definitions.
4719 * Invoking guix refresh:: Updating package definitions.
4720 * Invoking guix lint:: Finding errors in package definitions.
4721 * Invoking guix size:: Profiling disk usage.
4722 * Invoking guix graph:: Visualizing the graph of packages.
4723 * Invoking guix environment:: Setting up development environments.
4724 * Invoking guix publish:: Sharing substitutes.
4725 * Invoking guix challenge:: Challenging substitute servers.
4726 * Invoking guix copy:: Copying to and from a remote store.
4727 * Invoking guix container:: Process isolation.
4730 @node Invoking guix build
4731 @section Invoking @command{guix build}
4733 @cindex package building
4734 @cindex @command{guix build}
4735 The @command{guix build} command builds packages or derivations and
4736 their dependencies, and prints the resulting store paths. Note that it
4737 does not modify the user's profile---this is the job of the
4738 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4739 it is mainly useful for distribution developers.
4741 The general syntax is:
4744 guix build @var{options} @var{package-or-derivation}@dots{}
4747 As an example, the following command builds the latest versions of Emacs
4748 and of Guile, displays their build logs, and finally displays the
4749 resulting directories:
4752 guix build emacs guile
4755 Similarly, the following command builds all the available packages:
4758 guix build --quiet --keep-going \
4759 `guix package -A | cut -f1,2 --output-delimiter=@@`
4762 @var{package-or-derivation} may be either the name of a package found in
4763 the software distribution such as @code{coreutils} or
4764 @code{coreutils@@8.20}, or a derivation such as
4765 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4766 package with the corresponding name (and optionally version) is searched
4767 for among the GNU distribution modules (@pxref{Package Modules}).
4769 Alternatively, the @code{--expression} option may be used to specify a
4770 Scheme expression that evaluates to a package; this is useful when
4771 disambiguating among several same-named packages or package variants is
4774 There may be zero or more @var{options}. The available options are
4775 described in the subsections below.
4778 * Common Build Options:: Build options for most commands.
4779 * Package Transformation Options:: Creating variants of packages.
4780 * Additional Build Options:: Options specific to 'guix build'.
4783 @node Common Build Options
4784 @subsection Common Build Options
4786 A number of options that control the build process are common to
4787 @command{guix build} and other commands that can spawn builds, such as
4788 @command{guix package} or @command{guix archive}. These are the
4793 @item --load-path=@var{directory}
4794 @itemx -L @var{directory}
4795 Add @var{directory} to the front of the package module search path
4796 (@pxref{Package Modules}).
4798 This allows users to define their own packages and make them visible to
4799 the command-line tools.
4803 Keep the build tree of failed builds. Thus, if a build fails, its build
4804 tree is kept under @file{/tmp}, in a directory whose name is shown at
4805 the end of the build log. This is useful when debugging build issues.
4809 Keep going when some of the derivations fail to build; return only once
4810 all the builds have either completed or failed.
4812 The default behavior is to stop as soon as one of the specified
4813 derivations has failed.
4817 Do not build the derivations.
4820 When substituting a pre-built binary fails, fall back to building
4823 @item --substitute-urls=@var{urls}
4824 @anchor{client-substitute-urls}
4825 Consider @var{urls} the whitespace-separated list of substitute source
4826 URLs, overriding the default list of URLs of @command{guix-daemon}
4827 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
4829 This means that substitutes may be downloaded from @var{urls}, provided
4830 they are signed by a key authorized by the system administrator
4831 (@pxref{Substitutes}).
4833 When @var{urls} is the empty string, substitutes are effectively
4836 @item --no-substitutes
4837 Do not use substitutes for build products. That is, always build things
4838 locally instead of allowing downloads of pre-built binaries
4839 (@pxref{Substitutes}).
4842 Do not ``graft'' packages. In practice, this means that package updates
4843 available as grafts are not applied. @xref{Security Updates}, for more
4844 information on grafts.
4846 @item --rounds=@var{n}
4847 Build each derivation @var{n} times in a row, and raise an error if
4848 consecutive build results are not bit-for-bit identical.
4850 This is a useful way to detect non-deterministic builds processes.
4851 Non-deterministic build processes are a problem because they make it
4852 practically impossible for users to @emph{verify} whether third-party
4853 binaries are genuine. @xref{Invoking guix challenge}, for more.
4855 Note that, currently, the differing build results are not kept around,
4856 so you will have to manually investigate in case of an error---e.g., by
4857 stashing one of the build results with @code{guix archive --export}
4858 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
4861 @item --no-build-hook
4862 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
4863 (@pxref{Daemon Offload Setup}). That is, always build things locally
4864 instead of offloading builds to remote machines.
4866 @item --max-silent-time=@var{seconds}
4867 When the build or substitution process remains silent for more than
4868 @var{seconds}, terminate it and report a build failure.
4870 @item --timeout=@var{seconds}
4871 Likewise, when the build or substitution process lasts for more than
4872 @var{seconds}, terminate it and report a build failure.
4874 By default there is no timeout. This behavior can be restored with
4877 @item --verbosity=@var{level}
4878 Use the given verbosity level. @var{level} must be an integer between 0
4879 and 5; higher means more verbose output. Setting a level of 4 or more
4880 may be helpful when debugging setup issues with the build daemon.
4882 @item --cores=@var{n}
4884 Allow the use of up to @var{n} CPU cores for the build. The special
4885 value @code{0} means to use as many CPU cores as available.
4887 @item --max-jobs=@var{n}
4889 Allow at most @var{n} build jobs in parallel. @xref{Invoking
4890 guix-daemon, @code{--max-jobs}}, for details about this option and the
4891 equivalent @command{guix-daemon} option.
4895 Behind the scenes, @command{guix build} is essentially an interface to
4896 the @code{package-derivation} procedure of the @code{(guix packages)}
4897 module, and to the @code{build-derivations} procedure of the @code{(guix
4898 derivations)} module.
4900 In addition to options explicitly passed on the command line,
4901 @command{guix build} and other @command{guix} commands that support
4902 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
4904 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
4905 Users can define this variable to a list of command line options that
4906 will automatically be used by @command{guix build} and other
4907 @command{guix} commands that can perform builds, as in the example
4911 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
4914 These options are parsed independently, and the result is appended to
4915 the parsed command-line options.
4919 @node Package Transformation Options
4920 @subsection Package Transformation Options
4922 @cindex package variants
4923 Another set of command-line options supported by @command{guix build}
4924 and also @command{guix package} are @dfn{package transformation
4925 options}. These are options that make it possible to define @dfn{package
4926 variants}---for instance, packages built from different source code.
4927 This is a convenient way to create customized packages on the fly
4928 without having to type in the definitions of package variants
4929 (@pxref{Defining Packages}).
4933 @item --with-source=@var{source}
4934 Use @var{source} as the source of the corresponding package.
4935 @var{source} must be a file name or a URL, as for @command{guix
4936 download} (@pxref{Invoking guix download}).
4938 The ``corresponding package'' is taken to be the one specified on the
4939 command line the name of which matches the base of @var{source}---e.g.,
4940 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
4941 package is @code{guile}. Likewise, the version string is inferred from
4942 @var{source}; in the previous example, it is @code{2.0.10}.
4944 This option allows users to try out versions of packages other than the
4945 one provided by the distribution. The example below downloads
4946 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
4947 the @code{ed} package:
4950 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
4953 As a developer, @code{--with-source} makes it easy to test release
4957 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
4960 @dots{} or to build from a checkout in a pristine environment:
4963 $ git clone git://git.sv.gnu.org/guix.git
4964 $ guix build guix --with-source=./guix
4967 @item --with-input=@var{package}=@var{replacement}
4968 Replace dependency on @var{package} by a dependency on
4969 @var{replacement}. @var{package} must be a package name, and
4970 @var{replacement} must be a package specification such as @code{guile}
4971 or @code{guile@@1.8}.
4973 For instance, the following command builds Guix, but replaces its
4974 dependency on the current stable version of Guile with a dependency on
4975 the legacy version of Guile, @code{guile@@2.0}:
4978 guix build --with-input=guile=guile@@2.0 guix
4981 This is a recursive, deep replacement. So in this example, both
4982 @code{guix} and its dependency @code{guile-json} (which also depends on
4983 @code{guile}) get rebuilt against @code{guile@@2.0}.
4985 This is implemented using the @code{package-input-rewriting} Scheme
4986 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
4988 @item --with-graft=@var{package}=@var{replacement}
4989 This is similar to @code{--with-input} but with an important difference:
4990 instead of rebuilding the whole dependency chain, @var{replacement} is
4991 built and then @dfn{grafted} onto the binaries that were initially
4992 referring to @var{package}. @xref{Security Updates}, for more
4993 information on grafts.
4995 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
4996 and all its dependencies, replacing references to the version of GnuTLS
4997 they currently refer to:
5000 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5003 This has the advantage of being much faster than rebuilding everything.
5004 But there is a caveat: it works if and only if @var{package} and
5005 @var{replacement} are strictly compatible---for example, if they provide
5006 a library, the application binary interface (ABI) of those libraries
5007 must be compatible. If @var{replacement} is somehow incompatible with
5008 @var{package}, then the resulting package may be unusable. Use with
5013 @node Additional Build Options
5014 @subsection Additional Build Options
5016 The command-line options presented below are specific to @command{guix
5023 Build quietly, without displaying the build log. Upon completion, the
5024 build log is kept in @file{/var} (or similar) and can always be
5025 retrieved using the @option{--log-file} option.
5027 @item --file=@var{file}
5028 @itemx -f @var{file}
5030 Build the package or derivation that the code within @var{file}
5033 As an example, @var{file} might contain a package definition like this
5034 (@pxref{Defining Packages}):
5037 @verbatiminclude package-hello.scm
5040 @item --expression=@var{expr}
5041 @itemx -e @var{expr}
5042 Build the package or derivation @var{expr} evaluates to.
5044 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5045 guile-1.8)}, which unambiguously designates this specific variant of
5046 version 1.8 of Guile.
5048 Alternatively, @var{expr} may be a G-expression, in which case it is used
5049 as a build program passed to @code{gexp->derivation}
5050 (@pxref{G-Expressions}).
5052 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5053 (@pxref{The Store Monad}). The procedure must return a derivation as a
5054 monadic value, which is then passed through @code{run-with-store}.
5058 Build the source derivations of the packages, rather than the packages
5061 For instance, @code{guix build -S gcc} returns something like
5062 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5065 The returned source tarball is the result of applying any patches and
5066 code snippets specified in the package @code{origin} (@pxref{Defining
5070 Fetch and return the source of @var{package-or-derivation} and all their
5071 dependencies, recursively. This is a handy way to obtain a local copy
5072 of all the source code needed to build @var{packages}, allowing you to
5073 eventually build them even without network access. It is an extension
5074 of the @code{--source} option and can accept one of the following
5075 optional argument values:
5079 This value causes the @code{--sources} option to behave in the same way
5080 as the @code{--source} option.
5083 Build the source derivations of all packages, including any source that
5084 might be listed as @code{inputs}. This is the default value.
5087 $ guix build --sources tzdata
5088 The following derivations will be built:
5089 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5090 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5094 Build the source derivations of all packages, as well of all transitive
5095 inputs to the packages. This can be used e.g. to
5096 prefetch package source for later offline building.
5099 $ guix build --sources=transitive tzdata
5100 The following derivations will be built:
5101 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5102 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5103 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5104 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5105 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5106 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5112 @item --system=@var{system}
5113 @itemx -s @var{system}
5114 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5115 the system type of the build host.
5117 An example use of this is on Linux-based systems, which can emulate
5118 different personalities. For instance, passing
5119 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5120 to build packages in a complete 32-bit environment.
5122 @item --target=@var{triplet}
5123 @cindex cross-compilation
5124 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5125 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5126 configuration triplets,, autoconf, Autoconf}).
5128 @anchor{build-check}
5130 @cindex determinism, checking
5131 @cindex reproducibility, checking
5132 Rebuild @var{package-or-derivation}, which are already available in the
5133 store, and raise an error if the build results are not bit-for-bit
5136 This mechanism allows you to check whether previously installed
5137 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5138 of a package is deterministic. @xref{Invoking guix challenge}, for more
5139 background information and tools.
5141 When used in conjunction with @option{--keep-failed}, the differing
5142 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5143 This makes it easy to look for differences between the two results.
5146 @cindex repairing store items
5147 @cindex corruption, recovering from
5148 Attempt to repair the specified store items, if they are corrupt, by
5149 re-downloading or rebuilding them.
5151 This operation is not atomic and thus restricted to @code{root}.
5155 Return the derivation paths, not the output paths, of the given
5158 @item --root=@var{file}
5159 @itemx -r @var{file}
5160 Make @var{file} a symlink to the result, and register it as a garbage
5164 Return the build log file names or URLs for the given
5165 @var{package-or-derivation}, or raise an error if build logs are
5168 This works regardless of how packages or derivations are specified. For
5169 instance, the following invocations are equivalent:
5172 guix build --log-file `guix build -d guile`
5173 guix build --log-file `guix build guile`
5174 guix build --log-file guile
5175 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5178 If a log is unavailable locally, and unless @code{--no-substitutes} is
5179 passed, the command looks for a corresponding log on one of the
5180 substitute servers (as specified with @code{--substitute-urls}.)
5182 So for instance, imagine you want to see the build log of GDB on MIPS,
5183 but you are actually on an @code{x86_64} machine:
5186 $ guix build --log-file gdb -s mips64el-linux
5187 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5190 You can freely access a huge library of build logs!
5194 @node Invoking guix edit
5195 @section Invoking @command{guix edit}
5197 @cindex @command{guix edit}
5198 @cindex package definition, editing
5199 So many packages, so many source files! The @command{guix edit} command
5200 facilitates the life of users and packagers by pointing their editor at
5201 the source file containing the definition of the specified packages.
5205 guix edit gcc@@4.9 vim
5209 launches the program specified in the @code{VISUAL} or in the
5210 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5213 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5214 have created your own packages on @code{GUIX_PACKAGE_PATH}
5215 (@pxref{Defining Packages}), you will be able to edit the package
5216 recipes. Otherwise, you will be able to examine the read-only recipes
5217 for packages currently in the store.
5220 @node Invoking guix download
5221 @section Invoking @command{guix download}
5223 @cindex @command{guix download}
5224 @cindex downloading package sources
5225 When writing a package definition, developers typically need to download
5226 a source tarball, compute its SHA256 hash, and write that
5227 hash in the package definition (@pxref{Defining Packages}). The
5228 @command{guix download} tool helps with this task: it downloads a file
5229 from the given URI, adds it to the store, and prints both its file name
5230 in the store and its SHA256 hash.
5232 The fact that the downloaded file is added to the store saves bandwidth:
5233 when the developer eventually tries to build the newly defined package
5234 with @command{guix build}, the source tarball will not have to be
5235 downloaded again because it is already in the store. It is also a
5236 convenient way to temporarily stash files, which may be deleted
5237 eventually (@pxref{Invoking guix gc}).
5239 The @command{guix download} command supports the same URIs as used in
5240 package definitions. In particular, it supports @code{mirror://} URIs.
5241 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5242 Guile bindings for GnuTLS are available in the user's environment; when
5243 they are not available, an error is raised. @xref{Guile Preparations,
5244 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5245 GnuTLS-Guile}, for more information.
5247 @command{guix download} verifies HTTPS server certificates by loading
5248 the certificates of X.509 authorities from the directory pointed to by
5249 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5250 Certificates}), unless @option{--no-check-certificate} is used.
5252 The following options are available:
5255 @item --format=@var{fmt}
5257 Write the hash in the format specified by @var{fmt}. For more
5258 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5260 @item --no-check-certificate
5261 Do not validate the X.509 certificates of HTTPS servers.
5263 When using this option, you have @emph{absolutely no guarantee} that you
5264 are communicating with the authentic server responsible for the given
5265 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5267 @item --output=@var{file}
5268 @itemx -o @var{file}
5269 Save the downloaded file to @var{file} instead of adding it to the
5273 @node Invoking guix hash
5274 @section Invoking @command{guix hash}
5276 @cindex @command{guix hash}
5277 The @command{guix hash} command computes the SHA256 hash of a file.
5278 It is primarily a convenience tool for anyone contributing to the
5279 distribution: it computes the cryptographic hash of a file, which can be
5280 used in the definition of a package (@pxref{Defining Packages}).
5282 The general syntax is:
5285 guix hash @var{option} @var{file}
5288 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5289 hash of data read from standard input. @command{guix hash} has the
5294 @item --format=@var{fmt}
5296 Write the hash in the format specified by @var{fmt}.
5298 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5299 (@code{hex} and @code{hexadecimal} can be used as well).
5301 If the @option{--format} option is not specified, @command{guix hash}
5302 will output the hash in @code{nix-base32}. This representation is used
5303 in the definitions of packages.
5307 Compute the hash on @var{file} recursively.
5309 In this case, the hash is computed on an archive containing @var{file},
5310 including its children if it is a directory. Some of the metadata of
5311 @var{file} is part of the archive; for instance, when @var{file} is a
5312 regular file, the hash is different depending on whether @var{file} is
5313 executable or not. Metadata such as time stamps has no impact on the
5314 hash (@pxref{Invoking guix archive}).
5315 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5320 When combined with @option{--recursive}, exclude version control system
5321 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5324 As an example, here is how you would compute the hash of a Git checkout,
5325 which is useful when using the @code{git-fetch} method (@pxref{origin
5329 $ git clone http://example.org/foo.git
5335 @node Invoking guix import
5336 @section Invoking @command{guix import}
5338 @cindex importing packages
5339 @cindex package import
5340 @cindex package conversion
5341 @cindex Invoking @command{guix import}
5342 The @command{guix import} command is useful for people who would like to
5343 add a package to the distribution with as little work as
5344 possible---a legitimate demand. The command knows of a few
5345 repositories from which it can ``import'' package metadata. The result
5346 is a package definition, or a template thereof, in the format we know
5347 (@pxref{Defining Packages}).
5349 The general syntax is:
5352 guix import @var{importer} @var{options}@dots{}
5355 @var{importer} specifies the source from which to import package
5356 metadata, and @var{options} specifies a package identifier and other
5357 options specific to @var{importer}. Currently, the available
5362 Import metadata for the given GNU package. This provides a template
5363 for the latest version of that GNU package, including the hash of its
5364 source tarball, and its canonical synopsis and description.
5366 Additional information such as the package dependencies and its
5367 license needs to be figured out manually.
5369 For example, the following command returns a package definition for
5373 guix import gnu hello
5376 Specific command-line options are:
5379 @item --key-download=@var{policy}
5380 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5381 keys when verifying the package signature. @xref{Invoking guix
5382 refresh, @code{--key-download}}.
5387 Import metadata from the @uref{https://pypi.python.org/, Python Package
5388 Index}@footnote{This functionality requires Guile-JSON to be installed.
5389 @xref{Requirements}.}. Information is taken from the JSON-formatted
5390 description available at @code{pypi.python.org} and usually includes all
5391 the relevant information, including package dependencies. For maximum
5392 efficiency, it is recommended to install the @command{unzip} utility, so
5393 that the importer can unzip Python wheels and gather data from them.
5395 The command below imports metadata for the @code{itsdangerous} Python
5399 guix import pypi itsdangerous
5404 Import metadata from @uref{https://rubygems.org/,
5405 RubyGems}@footnote{This functionality requires Guile-JSON to be
5406 installed. @xref{Requirements}.}. Information is taken from the
5407 JSON-formatted description available at @code{rubygems.org} and includes
5408 most relevant information, including runtime dependencies. There are
5409 some caveats, however. The metadata doesn't distinguish between
5410 synopses and descriptions, so the same string is used for both fields.
5411 Additionally, the details of non-Ruby dependencies required to build
5412 native extensions is unavailable and left as an exercise to the
5415 The command below imports metadata for the @code{rails} Ruby package:
5418 guix import gem rails
5423 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5424 functionality requires Guile-JSON to be installed.
5425 @xref{Requirements}.}.
5426 Information is taken from the JSON-formatted metadata provided through
5427 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5428 relevant information, such as module dependencies. License information
5429 should be checked closely. If Perl is available in the store, then the
5430 @code{corelist} utility will be used to filter core modules out of the
5431 list of dependencies.
5433 The command command below imports metadata for the @code{Acme::Boolean}
5437 guix import cpan Acme::Boolean
5442 @cindex Bioconductor
5443 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5444 central repository for the @uref{http://r-project.org, GNU@tie{}R
5445 statistical and graphical environment}.
5447 Information is extracted from the @code{DESCRIPTION} file of the package.
5449 The command command below imports metadata for the @code{Cairo}
5453 guix import cran Cairo
5456 When @code{--recursive} is added, the importer will traverse the
5457 dependency graph of the given upstream package recursively and generate
5458 package expressions for all those packages that are not yet in Guix.
5460 When @code{--archive=bioconductor} is added, metadata is imported from
5461 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5462 packages for for the analysis and comprehension of high-throughput
5463 genomic data in bioinformatics.
5465 Information is extracted from the @code{DESCRIPTION} file of a package
5466 published on the web interface of the Bioconductor SVN repository.
5468 The command below imports metadata for the @code{GenomicRanges}
5472 guix import cran --archive=bioconductor GenomicRanges
5476 Import metadata from a local copy of the source of the
5477 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5478 relies on the @command{nix-instantiate} command of
5479 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5480 typically written in a mixture of Nix-language and Bash code. This
5481 command only imports the high-level package structure that is written in
5482 the Nix language. It normally includes all the basic fields of a
5485 When importing a GNU package, the synopsis and descriptions are replaced
5486 by their canonical upstream variant.
5488 Usually, you will first need to do:
5491 export NIX_REMOTE=daemon
5495 so that @command{nix-instantiate} does not try to open the Nix database.
5497 As an example, the command below imports the package definition of
5498 LibreOffice (more precisely, it imports the definition of the package
5499 bound to the @code{libreoffice} top-level attribute):
5502 guix import nix ~/path/to/nixpkgs libreoffice
5507 Import metadata from the Haskell community's central package archive
5508 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5509 Cabal files and includes all the relevant information, including package
5512 Specific command-line options are:
5517 Read a Cabal file from standard input.
5518 @item --no-test-dependencies
5520 Do not include dependencies required only by the test suites.
5521 @item --cabal-environment=@var{alist}
5522 @itemx -e @var{alist}
5523 @var{alist} is a Scheme alist defining the environment in which the
5524 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5525 @code{arch}, @code{impl} and a string representing the name of a flag.
5526 The value associated with a flag has to be either the symbol
5527 @code{true} or @code{false}. The value associated with other keys
5528 has to conform to the Cabal file format definition. The default value
5529 associated with the keys @code{os}, @code{arch} and @code{impl} is
5530 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5533 The command below imports metadata for the latest version of the
5534 @code{HTTP} Haskell package without including test dependencies and
5535 specifying the value of the flag @samp{network-uri} as @code{false}:
5538 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5541 A specific package version may optionally be specified by following the
5542 package name by an at-sign and a version number as in the following example:
5545 guix import hackage mtl@@2.1.3.1
5550 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5551 It takes a package name, looks up the package version included in a
5552 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5553 release and uses the @code{hackage} importer to retrieve its metadata.
5554 Note that it is up to you to select an LTS release compatible with the
5555 GHC compiler used by Guix.
5557 Specific command-line options are:
5560 @item --no-test-dependencies
5562 Do not include dependencies required only by the test suites.
5563 @item --lts-version=@var{version}
5564 @itemx -r @var{version}
5565 @var{version} is the desired LTS release version. If omitted the latest
5569 The command below imports metadata for the @code{HTTP} Haskell package
5570 included in the LTS Stackage release version 7.18:
5573 guix import stackage --lts-version=7.18 HTTP
5578 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5579 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5581 Specific command-line options are:
5584 @item --archive=@var{repo}
5585 @itemx -a @var{repo}
5586 @var{repo} identifies the archive repository from which to retrieve the
5587 information. Currently the supported repositories and their identifiers
5591 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5592 identifier. This is the default.
5594 Packages from @code{elpa.gnu.org} are signed with one of the keys
5595 contained in the GnuPG keyring at
5596 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5597 @code{emacs} package (@pxref{Package Installation, ELPA package
5598 signatures,, emacs, The GNU Emacs Manual}).
5601 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5602 @code{melpa-stable} identifier.
5605 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5612 Import metadata from the crates.io Rust package repository
5613 @uref{https://crates.io, crates.io}.
5616 The structure of the @command{guix import} code is modular. It would be
5617 useful to have more importers for other package formats, and your help
5618 is welcome here (@pxref{Contributing}).
5620 @node Invoking guix refresh
5621 @section Invoking @command{guix refresh}
5623 @cindex @command {guix refresh}
5624 The primary audience of the @command{guix refresh} command is developers
5625 of the GNU software distribution. By default, it reports any packages
5626 provided by the distribution that are outdated compared to the latest
5627 upstream version, like this:
5631 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5632 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5635 Alternately, one can specify packages to consider, in which case a
5636 warning is emitted for packages that lack an updater:
5639 $ guix refresh coreutils guile guile-ssh
5640 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5641 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5644 @command{guix refresh} browses the upstream repository of each package and determines
5645 the highest version number of the releases therein. The command
5646 knows how to update specific types of packages: GNU packages, ELPA
5647 packages, etc.---see the documentation for @option{--type} below. There
5648 are many packages, though, for which it lacks a method to determine
5649 whether a new upstream release is available. However, the mechanism is
5650 extensible, so feel free to get in touch with us to add a new method!
5652 When passed @code{--update}, it modifies distribution source files to
5653 update the version numbers and source tarball hashes of those package
5654 recipes (@pxref{Defining Packages}). This is achieved by downloading
5655 each package's latest source tarball and its associated OpenPGP
5656 signature, authenticating the downloaded tarball against its signature
5657 using @command{gpg}, and finally computing its hash. When the public
5658 key used to sign the tarball is missing from the user's keyring, an
5659 attempt is made to automatically retrieve it from a public key server;
5660 when this is successful, the key is added to the user's keyring; otherwise,
5661 @command{guix refresh} reports an error.
5663 The following options are supported:
5667 @item --expression=@var{expr}
5668 @itemx -e @var{expr}
5669 Consider the package @var{expr} evaluates to.
5671 This is useful to precisely refer to a package, as in this example:
5674 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
5677 This command lists the dependents of the ``final'' libc (essentially all
5682 Update distribution source files (package recipes) in place. This is
5683 usually run from a checkout of the Guix source tree (@pxref{Running
5684 Guix Before It Is Installed}):
5687 $ ./pre-inst-env guix refresh -s non-core -u
5690 @xref{Defining Packages}, for more information on package definitions.
5692 @item --select=[@var{subset}]
5693 @itemx -s @var{subset}
5694 Select all the packages in @var{subset}, one of @code{core} or
5697 The @code{core} subset refers to all the packages at the core of the
5698 distribution---i.e., packages that are used to build ``everything
5699 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
5700 changing one of these packages in the distribution entails a rebuild of
5701 all the others. Thus, such updates are an inconvenience to users in
5702 terms of build time or bandwidth used to achieve the upgrade.
5704 The @code{non-core} subset refers to the remaining packages. It is
5705 typically useful in cases where an update of the core packages would be
5708 @item --type=@var{updater}
5709 @itemx -t @var{updater}
5710 Select only packages handled by @var{updater} (may be a comma-separated
5711 list of updaters). Currently, @var{updater} may be one of:
5715 the updater for GNU packages;
5717 the updater for GNOME packages;
5719 the updater for KDE packages;
5721 the updater for X.org packages;
5723 the updater for packages hosted on kernel.org;
5725 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
5727 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
5729 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
5731 the updater for @uref{http://www.cpan.org/, CPAN} packages;
5733 the updater for @uref{https://pypi.python.org, PyPI} packages.
5735 the updater for @uref{https://rubygems.org, RubyGems} packages.
5737 the updater for @uref{https://github.com, GitHub} packages.
5739 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
5741 the updater for @uref{https://www.stackage.org, Stackage} packages.
5743 the updater for @uref{https://crates.io, Crates} packages.
5746 For instance, the following command only checks for updates of Emacs
5747 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
5750 $ guix refresh --type=elpa,cran
5751 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
5752 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
5757 In addition, @command{guix refresh} can be passed one or more package
5758 names, as in this example:
5761 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
5765 The command above specifically updates the @code{emacs} and
5766 @code{idutils} packages. The @code{--select} option would have no
5767 effect in this case.
5769 When considering whether to upgrade a package, it is sometimes
5770 convenient to know which packages would be affected by the upgrade and
5771 should be checked for compatibility. For this the following option may
5772 be used when passing @command{guix refresh} one or more package names:
5776 @item --list-updaters
5778 List available updaters and exit (see @option{--type} above.)
5780 For each updater, display the fraction of packages it covers; at the
5781 end, display the fraction of packages covered by all these updaters.
5783 @item --list-dependent
5785 List top-level dependent packages that would need to be rebuilt as a
5786 result of upgrading one or more packages.
5788 @xref{Invoking guix graph, the @code{reverse-package} type of
5789 @command{guix graph}}, for information on how to visualize the list of
5790 dependents of a package.
5794 Be aware that the @code{--list-dependent} option only
5795 @emph{approximates} the rebuilds that would be required as a result of
5796 an upgrade. More rebuilds might be required under some circumstances.
5799 $ guix refresh --list-dependent flex
5800 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
5801 hop-2.4.0 geiser-0.4 notmuch-0.18 mu-0.9.9.5 cflow-1.4 idutils-4.6 @dots{}
5804 The command above lists a set of packages that could be built to check
5805 for compatibility with an upgraded @code{flex} package.
5807 The following options can be used to customize GnuPG operation:
5811 @item --gpg=@var{command}
5812 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
5813 for in @code{$PATH}.
5815 @item --key-download=@var{policy}
5816 Handle missing OpenPGP keys according to @var{policy}, which may be one
5821 Always download missing OpenPGP keys from the key server, and add them
5822 to the user's GnuPG keyring.
5825 Never try to download missing OpenPGP keys. Instead just bail out.
5828 When a package signed with an unknown OpenPGP key is encountered, ask
5829 the user whether to download it or not. This is the default behavior.
5832 @item --key-server=@var{host}
5833 Use @var{host} as the OpenPGP key server when importing a public key.
5837 The @code{github} updater uses the
5838 @uref{https://developer.github.com/v3/, GitHub API} to query for new
5839 releases. When used repeatedly e.g. when refreshing all packages,
5840 GitHub will eventually refuse to answer any further API requests. By
5841 default 60 API requests per hour are allowed, and a full refresh on all
5842 GitHub packages in Guix requires more than this. Authentication with
5843 GitHub through the use of an API token alleviates these limits. To use
5844 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
5845 token procured from @uref{https://github.com/settings/tokens} or
5849 @node Invoking guix lint
5850 @section Invoking @command{guix lint}
5852 @cindex @command{guix lint}
5853 @cindex package, checking for errors
5854 The @command{guix lint} command is meant to help package developers avoid
5855 common errors and use a consistent style. It runs a number of checks on
5856 a given set of packages in order to find common mistakes in their
5857 definitions. Available @dfn{checkers} include (see
5858 @code{--list-checkers} for a complete list):
5863 Validate certain typographical and stylistic rules about package
5864 descriptions and synopses.
5866 @item inputs-should-be-native
5867 Identify inputs that should most likely be native inputs.
5872 @itemx source-file-name
5873 Probe @code{home-page} and @code{source} URLs and report those that are
5874 invalid. Suggest a @code{mirror://} URL when applicable. Check that
5875 the source file name is meaningful, e.g. is not
5876 just a version number or ``git-checkout'', without a declared
5877 @code{file-name} (@pxref{origin Reference}).
5880 @cindex security vulnerabilities
5881 @cindex CVE, Common Vulnerabilities and Exposures
5882 Report known vulnerabilities found in the Common Vulnerabilities and
5883 Exposures (CVE) databases of the current and past year
5884 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
5887 To view information about a particular vulnerability, visit pages such as:
5891 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
5893 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
5897 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
5898 @code{CVE-2015-7554}.
5900 Package developers can specify in package recipes the
5901 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
5902 name and version of the package when they differ from the name that Guix
5903 uses, as in this example:
5909 ;; CPE calls this package "grub2".
5910 (properties '((cpe-name . "grub2"))))
5914 Warn about obvious source code formatting issues: trailing white space,
5915 use of tabulations, etc.
5918 The general syntax is:
5921 guix lint @var{options} @var{package}@dots{}
5924 If no package is given on the command line, then all packages are checked.
5925 The @var{options} may be zero or more of the following:
5928 @item --list-checkers
5930 List and describe all the available checkers that will be run on packages
5935 Only enable the checkers specified in a comma-separated list using the
5936 names returned by @code{--list-checkers}.
5940 @node Invoking guix size
5941 @section Invoking @command{guix size}
5944 @cindex package size
5946 @cindex @command{guix size}
5947 The @command{guix size} command helps package developers profile the
5948 disk usage of packages. It is easy to overlook the impact of an
5949 additional dependency added to a package, or the impact of using a
5950 single output for a package that could easily be split (@pxref{Packages
5951 with Multiple Outputs}). Such are the typical issues that
5952 @command{guix size} can highlight.
5954 The command can be passed a package specification such as @code{gcc@@4.8}
5955 or @code{guile:debug}, or a file name in the store. Consider this
5959 $ guix size coreutils
5960 store item total self
5961 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
5962 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
5963 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
5964 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
5965 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
5966 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
5970 The store items listed here constitute the @dfn{transitive closure} of
5971 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
5972 would be returned by:
5975 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
5978 Here the output shows three columns next to store items. The first column,
5979 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
5980 the store item---that is, its own size plus the size of all its
5981 dependencies. The next column, labeled ``self'', shows the size of the
5982 item itself. The last column shows the ratio of the size of the item
5983 itself to the space occupied by all the items listed here.
5985 In this example, we see that the closure of Coreutils weighs in at
5986 70@tie{}MiB, half of which is taken by libc. (That libc represents a
5987 large fraction of the closure is not a problem @i{per se} because it is
5988 always available on the system anyway.)
5990 When the package passed to @command{guix size} is available in the
5991 store, @command{guix size} queries the daemon to determine its
5992 dependencies, and measures its size in the store, similar to @command{du
5993 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
5996 When the given package is @emph{not} in the store, @command{guix size}
5997 reports information based on the available substitutes
5998 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
5999 store items that are not even on disk, only available remotely.
6001 You can also specify several package names:
6004 $ guix size coreutils grep sed bash
6005 store item total self
6006 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6007 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6008 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6009 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6015 In this example we see that the combination of the four packages takes
6016 102.3@tie{}MiB in total, which is much less than the sum of each closure
6017 since they have a lot of dependencies in common.
6019 The available options are:
6023 @item --substitute-urls=@var{urls}
6024 Use substitute information from @var{urls}.
6025 @xref{client-substitute-urls, the same option for @code{guix build}}.
6027 @item --map-file=@var{file}
6028 Write a graphical map of disk usage in PNG format to @var{file}.
6030 For the example above, the map looks like this:
6032 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6033 produced by @command{guix size}}
6035 This option requires that
6036 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6037 installed and visible in Guile's module search path. When that is not
6038 the case, @command{guix size} fails as it tries to load it.
6040 @item --system=@var{system}
6041 @itemx -s @var{system}
6042 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6046 @node Invoking guix graph
6047 @section Invoking @command{guix graph}
6050 @cindex @command{guix graph}
6051 @cindex package dependencies
6052 Packages and their dependencies form a @dfn{graph}, specifically a
6053 directed acyclic graph (DAG). It can quickly become difficult to have a
6054 mental model of the package DAG, so the @command{guix graph} command
6055 provides a visual representation of the DAG. By default,
6056 @command{guix graph} emits a DAG representation in the input format of
6057 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6058 directly to the @command{dot} command of Graphviz. It can also emit an
6059 HTML page with embedded JavaScript code to display a ``chord diagram''
6060 in a Web browser, using the @uref{https://d3js.org/, d3.js} library.
6061 The general syntax is:
6064 guix graph @var{options} @var{package}@dots{}
6067 For example, the following command generates a PDF file representing the
6068 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6072 guix graph coreutils | dot -Tpdf > dag.pdf
6075 The output looks like this:
6077 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6079 Nice little graph, no?
6081 But there is more than one graph! The one above is concise: it is the
6082 graph of package objects, omitting implicit inputs such as GCC, libc,
6083 grep, etc. It is often useful to have such a concise graph, but
6084 sometimes one may want to see more details. @command{guix graph} supports
6085 several types of graphs, allowing you to choose the level of detail:
6089 This is the default type used in the example above. It shows the DAG of
6090 package objects, excluding implicit dependencies. It is concise, but
6091 filters out many details.
6093 @item reverse-package
6094 This shows the @emph{reverse} DAG of packages. For example:
6097 guix graph --type=reverse-package ocaml
6100 ... yields the graph of packages that depend on OCaml.
6102 Note that for core packages this can yield huge graphs. If all you want
6103 is to know the number of packages that depend on a given package, use
6104 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6105 @option{--list-dependent}}).
6108 This is the package DAG, @emph{including} implicit inputs.
6110 For instance, the following command:
6113 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6116 ... yields this bigger graph:
6118 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6120 At the bottom of the graph, we see all the implicit inputs of
6121 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6123 Now, note that the dependencies of these implicit inputs---that is, the
6124 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6125 here, for conciseness.
6128 Similar to @code{bag-emerged}, but this time including all the bootstrap
6131 @item bag-with-origins
6132 Similar to @code{bag}, but also showing origins and their dependencies.
6135 This is the most detailed representation: It shows the DAG of
6136 derivations (@pxref{Derivations}) and plain store items. Compared to
6137 the above representation, many additional nodes are visible, including
6138 build scripts, patches, Guile modules, etc.
6140 For this type of graph, it is also possible to pass a @file{.drv} file
6141 name instead of a package name, as in:
6144 guix graph -t derivation `guix system build -d my-config.scm`
6148 All the types above correspond to @emph{build-time dependencies}. The
6149 following graph type represents the @emph{run-time dependencies}:
6153 This is the graph of @dfn{references} of a package output, as returned
6154 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6156 If the given package output is not available in the store, @command{guix
6157 graph} attempts to obtain dependency information from substitutes.
6159 Here you can also pass a store file name instead of a package name. For
6160 example, the command below produces the reference graph of your profile
6161 (which can be big!):
6164 guix graph -t references `readlink -f ~/.guix-profile`
6168 This is the graph of the @dfn{referrers} of a store item, as returned by
6169 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6171 This relies exclusively on local information from your store. For
6172 instance, let us suppose that the current Inkscape is available in 10
6173 profiles on your machine; @command{guix graph -t referrers inkscape}
6174 will show a graph rooted at Inkscape and with those 10 profiles linked
6177 It can help determine what is preventing a store item from being garbage
6182 The available options are the following:
6185 @item --type=@var{type}
6186 @itemx -t @var{type}
6187 Produce a graph output of @var{type}, where @var{type} must be one of
6188 the values listed above.
6191 List the supported graph types.
6193 @item --backend=@var{backend}
6194 @itemx -b @var{backend}
6195 Produce a graph using the selected @var{backend}.
6197 @item --list-backends
6198 List the supported graph backends.
6200 Currently, the available backends are Graphviz and d3.js.
6202 @item --expression=@var{expr}
6203 @itemx -e @var{expr}
6204 Consider the package @var{expr} evaluates to.
6206 This is useful to precisely refer to a package, as in this example:
6209 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6214 @node Invoking guix environment
6215 @section Invoking @command{guix environment}
6217 @cindex reproducible build environments
6218 @cindex development environments
6219 @cindex @command{guix environment}
6220 @cindex environment, package build environment
6221 The purpose of @command{guix environment} is to assist hackers in
6222 creating reproducible development environments without polluting their
6223 package profile. The @command{guix environment} tool takes one or more
6224 packages, builds all of their inputs, and creates a shell
6225 environment to use them.
6227 The general syntax is:
6230 guix environment @var{options} @var{package}@dots{}
6233 The following example spawns a new shell set up for the development of
6237 guix environment guile
6240 If the needed dependencies are not built yet, @command{guix environment}
6241 automatically builds them. The environment of the new shell is an augmented
6242 version of the environment that @command{guix environment} was run in.
6243 It contains the necessary search paths for building the given package
6244 added to the existing environment variables. To create a ``pure''
6245 environment, in which the original environment variables have been unset,
6246 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6247 environment variables such as @code{PATH} in their @file{~/.bashrc}
6248 file. As a consequence, when @code{guix environment} launches it, Bash
6249 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6250 environment variables. It is an error to define such environment
6251 variables in @file{.bashrc}; instead, they should be defined in
6252 @file{.bash_profile}, which is sourced only by log-in shells.
6253 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6254 details on Bash start-up files.}.
6256 @vindex GUIX_ENVIRONMENT
6257 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6258 variable in the shell it spawns; its value is the file name of the
6259 profile of this environment. This allows users to, say, define a
6260 specific prompt for development environments in their @file{.bashrc}
6261 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6264 if [ -n "$GUIX_ENVIRONMENT" ]
6266 export PS1="\u@@\h \w [dev]\$ "
6271 ... or to browse the profile:
6274 $ ls "$GUIX_ENVIRONMENT/bin"
6277 Additionally, more than one package may be specified, in which case the
6278 union of the inputs for the given packages are used. For example, the
6279 command below spawns a shell where all of the dependencies of both Guile
6280 and Emacs are available:
6283 guix environment guile emacs
6286 Sometimes an interactive shell session is not desired. An arbitrary
6287 command may be invoked by placing the @code{--} token to separate the
6288 command from the rest of the arguments:
6291 guix environment guile -- make -j4
6294 In other situations, it is more convenient to specify the list of
6295 packages needed in the environment. For example, the following command
6296 runs @command{python} from an environment containing Python@tie{}2.7 and
6300 guix environment --ad-hoc python2-numpy python-2.7 -- python
6303 Furthermore, one might want the dependencies of a package and also some
6304 additional packages that are not build-time or runtime dependencies, but
6305 are useful when developing nonetheless. Because of this, the
6306 @code{--ad-hoc} flag is positional. Packages appearing before
6307 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6308 added to the environment. Packages appearing after are interpreted as
6309 packages that will be added to the environment directly. For example,
6310 the following command creates a Guix development environment that
6311 additionally includes Git and strace:
6314 guix environment guix --ad-hoc git strace
6317 Sometimes it is desirable to isolate the environment as much as
6318 possible, for maximal purity and reproducibility. In particular, when
6319 using Guix on a host distro that is not GuixSD, it is desirable to
6320 prevent access to @file{/usr/bin} and other system-wide resources from
6321 the development environment. For example, the following command spawns
6322 a Guile REPL in a ``container'' where only the store and the current
6323 working directory are mounted:
6326 guix environment --ad-hoc --container guile -- guile
6330 The @code{--container} option requires Linux-libre 3.19 or newer.
6333 The available options are summarized below.
6336 @item --root=@var{file}
6337 @itemx -r @var{file}
6338 @cindex persistent environment
6339 @cindex garbage collector root, for environments
6340 Make @var{file} a symlink to the profile for this environment, and
6341 register it as a garbage collector root.
6343 This is useful if you want to protect your environment from garbage
6344 collection, to make it ``persistent''.
6346 When this option is omitted, the environment is protected from garbage
6347 collection only for the duration of the @command{guix environment}
6348 session. This means that next time you recreate the same environment,
6349 you could have to rebuild or re-download packages.
6351 @item --expression=@var{expr}
6352 @itemx -e @var{expr}
6353 Create an environment for the package or list of packages that
6354 @var{expr} evaluates to.
6356 For example, running:
6359 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6362 starts a shell with the environment for this specific variant of the
6368 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6371 starts a shell with all the GuixSD base packages available.
6373 The above commands only use the default output of the given packages.
6374 To select other outputs, two element tuples can be specified:
6377 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6380 @item --load=@var{file}
6381 @itemx -l @var{file}
6382 Create an environment for the package or list of packages that the code
6383 within @var{file} evaluates to.
6385 As an example, @var{file} might contain a definition like this
6386 (@pxref{Defining Packages}):
6389 @verbatiminclude environment-gdb.scm
6393 Include all specified packages in the resulting environment, as if an
6394 @i{ad hoc} package were defined with them as inputs. This option is
6395 useful for quickly creating an environment without having to write a
6396 package expression to contain the desired inputs.
6398 For instance, the command:
6401 guix environment --ad-hoc guile guile-sdl -- guile
6404 runs @command{guile} in an environment where Guile and Guile-SDL are
6407 Note that this example implicitly asks for the default output of
6408 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6409 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6410 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6412 This option may be composed with the default behavior of @command{guix
6413 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6414 as packages whose dependencies will be added to the environment, the
6415 default behavior. Packages appearing after are interpreted as packages
6416 that will be added to the environment directly.
6419 Unset existing environment variables when building the new environment.
6420 This has the effect of creating an environment in which search paths
6421 only contain package inputs.
6423 @item --search-paths
6424 Display the environment variable definitions that make up the
6427 @item --system=@var{system}
6428 @itemx -s @var{system}
6429 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6434 Run @var{command} within an isolated container. The current working
6435 directory outside the container is mapped inside the container.
6436 Additionally, a dummy home directory is created that matches the current
6437 user's home directory, and @file{/etc/passwd} is configured accordingly.
6438 The spawned process runs as the current user outside the container, but
6439 has root privileges in the context of the container.
6443 For containers, share the network namespace with the host system.
6444 Containers created without this flag only have access to the loopback
6447 @item --expose=@var{source}[=@var{target}]
6448 For containers, expose the file system @var{source} from the host system
6449 as the read-only file system @var{target} within the container. If
6450 @var{target} is not specified, @var{source} is used as the target mount
6451 point in the container.
6453 The example below spawns a Guile REPL in a container in which the user's
6454 home directory is accessible read-only via the @file{/exchange}
6458 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6461 @item --share=@var{source}[=@var{target}]
6462 For containers, share the file system @var{source} from the host system
6463 as the writable file system @var{target} within the container. If
6464 @var{target} is not specified, @var{source} is used as the target mount
6465 point in the container.
6467 The example below spawns a Guile REPL in a container in which the user's
6468 home directory is accessible for both reading and writing via the
6469 @file{/exchange} directory:
6472 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6476 @command{guix environment}
6477 also supports all of the common build options that @command{guix
6478 build} supports (@pxref{Common Build Options}).
6481 @node Invoking guix publish
6482 @section Invoking @command{guix publish}
6484 @cindex @command{guix publish}
6485 The purpose of @command{guix publish} is to enable users to easily share
6486 their store with others, who can then use it as a substitute server
6487 (@pxref{Substitutes}).
6489 When @command{guix publish} runs, it spawns an HTTP server which allows
6490 anyone with network access to obtain substitutes from it. This means
6491 that any machine running Guix can also act as if it were a build farm,
6492 since the HTTP interface is compatible with Hydra, the software behind
6493 the @code{hydra.gnu.org} build farm.
6495 For security, each substitute is signed, allowing recipients to check
6496 their authenticity and integrity (@pxref{Substitutes}). Because
6497 @command{guix publish} uses the signing key of the system, which is only
6498 readable by the system administrator, it must be started as root; the
6499 @code{--user} option makes it drop root privileges early on.
6501 The signing key pair must be generated before @command{guix publish} is
6502 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6505 The general syntax is:
6508 guix publish @var{options}@dots{}
6511 Running @command{guix publish} without any additional arguments will
6512 spawn an HTTP server on port 8080:
6518 Once a publishing server has been authorized (@pxref{Invoking guix
6519 archive}), the daemon may download substitutes from it:
6522 guix-daemon --substitute-urls=http://example.org:8080
6525 By default, @command{guix publish} compresses archives on the fly as it
6526 serves them. This ``on-the-fly'' mode is convenient in that it requires
6527 no setup and is immediately available. However, when serving lots of
6528 clients, we recommend using the @option{--cache} option, which enables
6529 caching of the archives before they are sent to clients---see below for
6532 As a bonus, @command{guix publish} also serves as a content-addressed
6533 mirror for source files referenced in @code{origin} records
6534 (@pxref{origin Reference}). For instance, assuming @command{guix
6535 publish} is running on @code{example.org}, the following URL returns the
6536 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6537 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6540 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6543 Obviously, these URLs only work for files that are in the store; in
6544 other cases, they return 404 (``Not Found'').
6546 The following options are available:
6549 @item --port=@var{port}
6550 @itemx -p @var{port}
6551 Listen for HTTP requests on @var{port}.
6553 @item --listen=@var{host}
6554 Listen on the network interface for @var{host}. The default is to
6555 accept connections from any interface.
6557 @item --user=@var{user}
6558 @itemx -u @var{user}
6559 Change privileges to @var{user} as soon as possible---i.e., once the
6560 server socket is open and the signing key has been read.
6562 @item --compression[=@var{level}]
6563 @itemx -C [@var{level}]
6564 Compress data using the given @var{level}. When @var{level} is zero,
6565 disable compression. The range 1 to 9 corresponds to different gzip
6566 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6569 Unless @option{--cache} is used, compression occurs on the fly and
6570 the compressed streams are not
6571 cached. Thus, to reduce load on the machine that runs @command{guix
6572 publish}, it may be a good idea to choose a low compression level, to
6573 run @command{guix publish} behind a caching proxy, or to use
6574 @option{--cache}. Using @option{--cache} has the advantage that it
6575 allows @command{guix publish} to add @code{Content-Length} HTTP header
6578 @item --cache=@var{directory}
6579 @itemx -c @var{directory}
6580 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6581 and only serve archives that are in cache.
6583 When this option is omitted, archives and meta-data are created
6584 on-the-fly. This can reduce the available bandwidth, especially when
6585 compression is enabled, since this may become CPU-bound. Another
6586 drawback of the default mode is that the length of archives is not known
6587 in advance, so @command{guix publish} does not add a
6588 @code{Content-Length} HTTP header to its responses, which in turn
6589 prevents clients from knowing the amount of data being downloaded.
6591 Conversely, when @option{--cache} is used, the first request for a store
6592 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6593 background process to @dfn{bake} the archive---computing its
6594 @code{.narinfo} and compressing the archive, if needed. Once the
6595 archive is cached in @var{directory}, subsequent requests succeed and
6596 are served directly from the cache, which guarantees that clients get
6597 the best possible bandwidth.
6599 The ``baking'' process is performed by worker threads. By default, one
6600 thread per CPU core is created, but this can be customized. See
6601 @option{--workers} below.
6603 @item --workers=@var{N}
6604 When @option{--cache} is used, request the allocation of @var{N} worker
6605 threads to ``bake'' archives.
6607 @item --ttl=@var{ttl}
6608 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6609 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6610 days, @code{1m} means 1 month, and so on.
6612 This allows the user's Guix to keep substitute information in cache for
6613 @var{ttl}. However, note that @code{guix publish} does not itself
6614 guarantee that the store items it provides will indeed remain available
6615 for as long as @var{ttl}.
6617 @item --nar-path=@var{path}
6618 Use @var{path} as the prefix for the URLs of ``nar'' files
6619 (@pxref{Invoking guix archive, normalized archives}).
6621 By default, nars are served at a URL such as
6622 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6623 change the @code{/nar} part to @var{path}.
6625 @item --public-key=@var{file}
6626 @itemx --private-key=@var{file}
6627 Use the specific @var{file}s as the public/private key pair used to sign
6628 the store items being published.
6630 The files must correspond to the same key pair (the private key is used
6631 for signing and the public key is merely advertised in the signature
6632 metadata). They must contain keys in the canonical s-expression format
6633 as produced by @command{guix archive --generate-key} (@pxref{Invoking
6634 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
6635 @file{/etc/guix/signing-key.sec} are used.
6637 @item --repl[=@var{port}]
6638 @itemx -r [@var{port}]
6639 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
6640 Reference Manual}) on @var{port} (37146 by default). This is used
6641 primarily for debugging a running @command{guix publish} server.
6644 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
6645 instantiate a @code{guix-publish-service-type} service in the @code{services} field
6646 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
6647 @code{guix-publish-service-type}}).
6649 If you are instead running Guix on a ``foreign distro'', follow these
6654 If your host distro uses the systemd init system:
6657 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
6658 /etc/systemd/system/
6659 # systemctl start guix-publish && systemctl enable guix-publish
6663 If your host distro uses the Upstart init system:
6666 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
6667 # start guix-publish
6671 Otherwise, proceed similarly with your distro's init system.
6674 @node Invoking guix challenge
6675 @section Invoking @command{guix challenge}
6677 @cindex reproducible builds
6678 @cindex verifiable builds
6679 @cindex @command{guix challenge}
6681 Do the binaries provided by this server really correspond to the source
6682 code it claims to build? Is a package build process deterministic?
6683 These are the questions the @command{guix challenge} command attempts to
6686 The former is obviously an important question: Before using a substitute
6687 server (@pxref{Substitutes}), one had better @emph{verify} that it
6688 provides the right binaries, and thus @emph{challenge} it. The latter
6689 is what enables the former: If package builds are deterministic, then
6690 independent builds of the package should yield the exact same result,
6691 bit for bit; if a server provides a binary different from the one
6692 obtained locally, it may be either corrupt or malicious.
6694 We know that the hash that shows up in @file{/gnu/store} file names is
6695 the hash of all the inputs of the process that built the file or
6696 directory---compilers, libraries, build scripts,
6697 etc. (@pxref{Introduction}). Assuming deterministic build processes,
6698 one store file name should map to exactly one build output.
6699 @command{guix challenge} checks whether there is, indeed, a single
6700 mapping by comparing the build outputs of several independent builds of
6701 any given store item.
6703 The command output looks like this:
6706 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
6707 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
6708 updating list of substitutes from 'https://guix.example.org'... 100.0%
6709 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
6710 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6711 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6712 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
6713 /gnu/store/@dots{}-git-2.5.0 contents differ:
6714 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
6715 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
6716 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
6717 /gnu/store/@dots{}-pius-2.1.1 contents differ:
6718 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6719 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6720 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
6724 In this example, @command{guix challenge} first scans the store to
6725 determine the set of locally-built derivations---as opposed to store
6726 items that were downloaded from a substitute server---and then queries
6727 all the substitute servers. It then reports those store items for which
6728 the servers obtained a result different from the local build.
6730 @cindex non-determinism, in package builds
6731 As an example, @code{guix.example.org} always gets a different answer.
6732 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
6733 case of Git. This might indicate that the build process of Git is
6734 non-deterministic, meaning that its output varies as a function of
6735 various things that Guix does not fully control, in spite of building
6736 packages in isolated environments (@pxref{Features}). Most common
6737 sources of non-determinism include the addition of timestamps in build
6738 results, the inclusion of random numbers, and directory listings sorted
6739 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
6742 To find out what is wrong with this Git binary, we can do something along
6743 these lines (@pxref{Invoking guix archive}):
6746 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
6747 | guix archive -x /tmp/git
6748 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
6751 This command shows the difference between the files resulting from the
6752 local build, and the files resulting from the build on
6753 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
6754 diffutils, Comparing and Merging Files}). The @command{diff} command
6755 works great for text files. When binary files differ, a better option
6756 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
6757 visualize differences for all kinds of files.
6759 Once you have done that work, you can tell whether the differences are due
6760 to a non-deterministic build process or to a malicious server. We try
6761 hard to remove sources of non-determinism in packages to make it easier
6762 to verify substitutes, but of course, this is a process that
6763 involves not just Guix, but a large part of the free software community.
6764 In the meantime, @command{guix challenge} is one tool to help address
6767 If you are writing packages for Guix, you are encouraged to check
6768 whether @code{hydra.gnu.org} and other substitute servers obtain the
6769 same build result as you did with:
6772 $ guix challenge @var{package}
6776 where @var{package} is a package specification such as
6777 @code{guile@@2.0} or @code{glibc:debug}.
6779 The general syntax is:
6782 guix challenge @var{options} [@var{packages}@dots{}]
6785 When a difference is found between the hash of a locally-built item and
6786 that of a server-provided substitute, or among substitutes provided by
6787 different servers, the command displays it as in the example above and
6788 its exit code is 2 (other non-zero exit codes denote other kinds of
6791 The one option that matters is:
6795 @item --substitute-urls=@var{urls}
6796 Consider @var{urls} the whitespace-separated list of substitute source
6801 Show details about matches (identical contents) in addition to
6802 information about mismatches.
6806 @node Invoking guix copy
6807 @section Invoking @command{guix copy}
6809 @cindex copy, of store items, over SSH
6810 @cindex SSH, copy of store items
6811 @cindex sharing store items across machines
6812 @cindex transferring store items across machines
6813 The @command{guix copy} command copies items from the store of one
6814 machine to that of another machine over a secure shell (SSH)
6815 connection@footnote{This command is available only when Guile-SSH was
6816 found. @xref{Requirements}, for details.}. For example, the following
6817 command copies the @code{coreutils} package, the user's profile, and all
6818 their dependencies over to @var{host}, logged in as @var{user}:
6821 guix copy --to=@var{user}@@@var{host} \
6822 coreutils `readlink -f ~/.guix-profile`
6825 If some of the items to be copied are already present on @var{host},
6826 they are not actually sent.
6828 The command below retrieves @code{libreoffice} and @code{gimp} from
6829 @var{host}, assuming they are available there:
6832 guix copy --from=@var{host} libreoffice gimp
6835 The SSH connection is established using the Guile-SSH client, which is
6836 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
6837 @file{~/.ssh/config}, and uses the SSH agent for authentication.
6839 The key used to sign items that are sent must be accepted by the remote
6840 machine. Likewise, the key used by the remote machine to sign items you
6841 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
6842 own daemon. @xref{Invoking guix archive}, for more information about
6843 store item authentication.
6845 The general syntax is:
6848 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
6851 You must always specify one of the following options:
6854 @item --to=@var{spec}
6855 @itemx --from=@var{spec}
6856 Specify the host to send to or receive from. @var{spec} must be an SSH
6857 spec such as @code{example.org}, @code{charlie@@example.org}, or
6858 @code{charlie@@example.org:2222}.
6861 The @var{items} can be either package names, such as @code{gimp}, or
6862 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
6864 When specifying the name of a package to send, it is first built if
6865 needed, unless @option{--dry-run} was specified. Common build options
6866 are supported (@pxref{Common Build Options}).
6869 @node Invoking guix container
6870 @section Invoking @command{guix container}
6872 @cindex @command{guix container}
6874 As of version @value{VERSION}, this tool is experimental. The interface
6875 is subject to radical change in the future.
6878 The purpose of @command{guix container} is to manipulate processes
6879 running within an isolated environment, commonly known as a
6880 ``container'', typically created by the @command{guix environment}
6881 (@pxref{Invoking guix environment}) and @command{guix system container}
6882 (@pxref{Invoking guix system}) commands.
6884 The general syntax is:
6887 guix container @var{action} @var{options}@dots{}
6890 @var{action} specifies the operation to perform with a container, and
6891 @var{options} specifies the context-specific arguments for the action.
6893 The following actions are available:
6897 Execute a command within the context of a running container.
6902 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
6905 @var{pid} specifies the process ID of the running container.
6906 @var{program} specifies an executable file name within the root file
6907 system of the container. @var{arguments} are the additional options that
6908 will be passed to @var{program}.
6910 The following command launches an interactive login shell inside a
6911 GuixSD container, started by @command{guix system container}, and whose
6915 guix container exec 9001 /run/current-system/profile/bin/bash --login
6918 Note that the @var{pid} cannot be the parent process of a container. It
6919 must be PID 1 of the container or one of its child processes.
6923 @c *********************************************************************
6924 @node GNU Distribution
6925 @chapter GNU Distribution
6927 @cindex Guix System Distribution
6929 Guix comes with a distribution of the GNU system consisting entirely of
6930 free software@footnote{The term ``free'' here refers to the
6931 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
6932 users of that software}.}. The
6933 distribution can be installed on its own (@pxref{System Installation}),
6934 but it is also possible to install Guix as a package manager on top of
6935 an installed GNU/Linux system (@pxref{Installation}). To distinguish
6936 between the two, we refer to the standalone distribution as the Guix
6937 System Distribution, or GuixSD.
6939 The distribution provides core GNU packages such as GNU libc, GCC, and
6940 Binutils, as well as many GNU and non-GNU applications. The complete
6941 list of available packages can be browsed
6942 @url{http://www.gnu.org/software/guix/packages,on-line} or by
6943 running @command{guix package} (@pxref{Invoking guix package}):
6946 guix package --list-available
6949 Our goal is to provide a practical 100% free software distribution of
6950 Linux-based and other variants of GNU, with a focus on the promotion and
6951 tight integration of GNU components, and an emphasis on programs and
6952 tools that help users exert that freedom.
6954 Packages are currently available on the following platforms:
6959 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
6962 Intel 32-bit architecture (IA32), Linux-Libre kernel;
6965 ARMv7-A architecture with hard float, Thumb-2 and NEON,
6966 using the EABI hard-float application binary interface (ABI),
6967 and Linux-Libre kernel.
6970 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
6971 currently in an experimental stage, with limited support.
6972 @xref{Contributing}, for how to help!
6974 @item mips64el-linux
6975 little-endian 64-bit MIPS processors, specifically the Loongson series,
6976 n32 ABI, and Linux-Libre kernel.
6980 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
6983 For information on porting to other architectures or kernels,
6987 * System Installation:: Installing the whole operating system.
6988 * System Configuration:: Configuring the operating system.
6989 * Documentation:: Browsing software user manuals.
6990 * Installing Debugging Files:: Feeding the debugger.
6991 * Security Updates:: Deploying security fixes quickly.
6992 * Package Modules:: Packages from the programmer's viewpoint.
6993 * Packaging Guidelines:: Growing the distribution.
6994 * Bootstrapping:: GNU/Linux built from scratch.
6995 * Porting:: Targeting another platform or kernel.
6998 Building this distribution is a cooperative effort, and you are invited
6999 to join! @xref{Contributing}, for information about how you can help.
7001 @node System Installation
7002 @section System Installation
7004 @cindex installing GuixSD
7005 @cindex Guix System Distribution
7006 This section explains how to install the Guix System Distribution (GuixSD)
7007 on a machine. The Guix package manager can
7008 also be installed on top of a running GNU/Linux system,
7009 @pxref{Installation}.
7013 @c This paragraph is for people reading this from tty2 of the
7014 @c installation image.
7015 You are reading this documentation with an Info reader. For details on
7016 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7017 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7018 Info}. Hit @kbd{l} afterwards to come back here.
7020 Alternately, run @command{info info} in another tty to keep the manual
7026 * Limitations:: What you can expect.
7027 * Hardware Considerations:: Supported hardware.
7028 * USB Stick Installation:: Preparing the installation medium.
7029 * Preparing for Installation:: Networking, partitioning, etc.
7030 * Proceeding with the Installation:: The real thing.
7031 * Installing GuixSD in a VM:: GuixSD playground.
7032 * Building the Installation Image:: How this comes to be.
7036 @subsection Limitations
7038 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7039 not production-ready. It may contain bugs and lack important
7040 features. Thus, if you are looking for a stable production system that
7041 respects your freedom as a computer user, a good solution at this point
7042 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7043 the more established GNU/Linux distributions}. We hope you can soon switch
7044 to the GuixSD without fear, of course. In the meantime, you can
7045 also keep using your distribution and try out the package manager on top
7046 of it (@pxref{Installation}).
7048 Before you proceed with the installation, be aware of the following
7049 noteworthy limitations applicable to version @value{VERSION}:
7053 The installation process does not include a graphical user interface and
7054 requires familiarity with GNU/Linux (see the following subsections to
7055 get a feel of what that means.)
7058 Support for the Logical Volume Manager (LVM) is missing.
7061 Few system services are currently supported out-of-the-box
7065 More than 5,000 packages are available, but you may
7066 occasionally find that a useful package is missing.
7069 GNOME, Xfce, and Enlightenment are available (@pxref{Desktop Services}),
7070 as well as a number of X11 window managers. However, some graphical
7071 applications may be missing, as well as KDE.
7074 You have been warned! But more than a disclaimer, this is an invitation
7075 to report issues (and success stories!), and to join us in improving it.
7076 @xref{Contributing}, for more info.
7079 @node Hardware Considerations
7080 @subsection Hardware Considerations
7082 @cindex hardware support on GuixSD
7083 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7084 builds around the kernel Linux-libre, which means that only hardware for
7085 which free software drivers and firmware exist is supported. Nowadays,
7086 a wide range of off-the-shelf hardware is supported on
7087 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7088 Ethernet controllers. Unfortunately, there are still areas where
7089 hardware vendors deny users control over their own computing, and such
7090 hardware is not supported on GuixSD.
7092 @cindex WiFi, hardware support
7093 One of the main areas where free drivers or firmware are lacking is WiFi
7094 devices. WiFi devices known to work include those using Atheros chips
7095 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7096 driver, and those using Broadcom/AirForce chips (BCM43xx with
7097 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7098 Linux-libre driver. Free firmware exists for both and is available
7099 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7100 (@pxref{operating-system Reference, @code{firmware}}).
7102 @cindex RYF, Respects Your Freedom
7103 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7104 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7105 certification program for hardware products that respect your freedom
7106 and your privacy and ensure that you have control over your device. We
7107 encourage you to check the list of RYF-certified devices.
7109 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7110 web site. It contains a catalog of hardware devices with information
7111 about their support in GNU/Linux.
7114 @node USB Stick Installation
7115 @subsection USB Stick Installation
7117 An installation image for USB sticks can be downloaded from
7118 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
7119 where @var{system} is one of:
7123 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7126 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7129 @c start duplication of authentication part from ``Binary Installation''
7130 Make sure to download the associated @file{.sig} file and to verify the
7131 authenticity of the image against it, along these lines:
7134 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7135 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7138 If that command fails because you do not have the required public key,
7139 then run this command to import it:
7142 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7146 and rerun the @code{gpg --verify} command.
7149 This image contains a single partition with the tools necessary for an
7150 installation. It is meant to be copied @emph{as is} to a large-enough
7153 To copy the image to a USB stick, follow these steps:
7157 Decompress the image using the @command{xz} command:
7160 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
7164 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7165 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7166 copy the image with:
7169 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
7172 Access to @file{/dev/sdX} usually requires root privileges.
7175 Once this is done, you should be able to reboot the system and boot from
7176 the USB stick. The latter usually requires you to get in the BIOS' boot
7177 menu, where you can choose to boot from the USB stick.
7179 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7180 GuixSD in a virtual machine (VM).
7182 @node Preparing for Installation
7183 @subsection Preparing for Installation
7185 Once you have successfully booted the image on the USB stick, you should
7186 end up with a root prompt. Several console TTYs are configured and can
7187 be used to run commands as root. TTY2 shows this documentation,
7188 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7189 Stand-alone GNU Info}). The installation system runs the GPM mouse
7190 daemon, which allows you to select text with the left mouse button and
7191 to paste it with the middle button.
7194 Installation requires access to the Internet so that any missing
7195 dependencies of your system configuration can be downloaded. See the
7196 ``Networking'' section below.
7199 The installation system includes many common tools needed for this task.
7200 But it is also a full-blown GuixSD system, which means that you can
7201 install additional packages, should you need it, using @command{guix
7202 package} (@pxref{Invoking guix package}).
7204 @subsubsection Keyboard Layout
7206 @cindex keyboard layout
7207 The installation image uses the US qwerty keyboard layout. If you want
7208 to change it, you can use the @command{loadkeys} command. For example,
7209 the following command selects the Dvorak keyboard layout:
7215 See the files under @file{/run/current-system/profile/share/keymaps} for
7216 a list of available keyboard layouts. Run @command{man loadkeys} for
7219 @subsubsection Networking
7221 Run the following command see what your network interfaces are called:
7228 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7234 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7235 Wired interfaces have a name starting with @samp{e}; for example, the
7236 interface corresponding to the first on-board Ethernet controller is
7237 called @samp{eno1}. Wireless interfaces have a name starting with
7238 @samp{w}, like @samp{w1p2s0}.
7241 @item Wired connection
7242 To configure a wired network run the following command, substituting
7243 @var{interface} with the name of the wired interface you want to use.
7246 ifconfig @var{interface} up
7249 @item Wireless connection
7252 To configure wireless networking, you can create a configuration file
7253 for the @command{wpa_supplicant} configuration tool (its location is not
7254 important) using one of the available text editors such as
7258 zile wpa_supplicant.conf
7261 As an example, the following stanza can go to this file and will work
7262 for many wireless networks, provided you give the actual SSID and
7263 passphrase for the network you are connecting to:
7267 ssid="@var{my-ssid}"
7269 psk="the network's secret passphrase"
7273 Start the wireless service and run it in the background with the
7274 following command (substitute @var{interface} with the name of the
7275 network interface you want to use):
7278 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7281 Run @command{man wpa_supplicant} for more information.
7285 At this point, you need to acquire an IP address. On a network where IP
7286 addresses are automatically assigned @i{via} DHCP, you can run:
7289 dhclient -v @var{interface}
7292 Try to ping a server to see if networking is up and running:
7298 Setting up network access is almost always a requirement because the
7299 image does not contain all the software and tools that may be needed.
7301 @subsubsection Disk Partitioning
7303 Unless this has already been done, the next step is to partition, and
7304 then format the target partition(s).
7306 The installation image includes several partitioning tools, including
7307 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7308 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7309 the partition layout you want:
7315 If your disk uses the GUID Partition Table (GPT) format and you plan to
7316 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7317 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7320 Once you are done partitioning the target hard disk drive, you have to
7321 create a file system on the relevant partition(s)@footnote{Currently
7322 GuixSD only supports ext4 and btrfs file systems. In particular, code
7323 that reads partition UUIDs and labels only works for these file system
7326 Preferably, assign partitions a label so that you can easily and
7327 reliably refer to them in @code{file-system} declarations (@pxref{File
7328 Systems}). This is typically done using the @code{-L} option of
7329 @command{mkfs.ext4} and related commands. So, assuming the target root
7330 partition lives at @file{/dev/sda1}, a file system with the label
7331 @code{my-root} can be created with:
7334 mkfs.ext4 -L my-root /dev/sda1
7337 @cindex encrypted disk
7338 If you are instead planning to encrypt the root partition, you can use
7339 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7340 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7341 @code{man cryptsetup}} for more information.) Assuming you want to
7342 store the root partition on @file{/dev/sda1}, the command sequence would
7343 be along these lines:
7346 cryptsetup luksFormat /dev/sda1
7347 cryptsetup open --type luks /dev/sda1 my-partition
7348 mkfs.ext4 -L my-root /dev/mapper/my-partition
7351 Once that is done, mount the target root partition under @file{/mnt}
7352 with a command like (again, assuming @code{my-root} is the label of the
7356 mount LABEL=my-root /mnt
7359 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7360 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7361 sure to initialize them with @command{mkswap}. Assuming you have one
7362 swap partition on @file{/dev/sda2}, you would run:
7369 Alternatively, you may use a swap file. For example, assuming that in
7370 the new system you want to use the file @file{/swapfile} as a swap file,
7371 you would run@footnote{This example will work for many types of file
7372 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7373 btrfs), the required steps may be different. For details, see the
7374 manual pages for @command{mkswap} and @command{swapon}.}:
7377 # This is 10 GiB of swap space. Adjust "count" to change the size.
7378 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7379 # For security, make the file readable and writable only by root.
7380 chmod 600 /mnt/swapfile
7381 mkswap /mnt/swapfile
7382 swapon /mnt/swapfile
7385 Note that if you have encrypted the root partition and created a swap
7386 file in its file system as described above, then the encryption also
7387 protects the swap file, just like any other file in that file system.
7389 @node Proceeding with the Installation
7390 @subsection Proceeding with the Installation
7392 With the target partitions ready and the target root mounted on
7393 @file{/mnt}, we're ready to go. First, run:
7396 herd start cow-store /mnt
7399 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7400 during the installation phase are written to the target disk on @file{/mnt}
7401 rather than kept in memory. This is necessary because the first phase of
7402 the @command{guix system init} command (see below) entails downloads or
7403 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7405 Next, you have to edit a file and
7406 provide the declaration of the operating system to be installed. To
7407 that end, the installation system comes with three text editors: GNU nano
7408 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7409 nvi (a clone of the original BSD @command{vi} editor).
7410 We strongly recommend storing that file on the target root file system, say,
7411 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7412 configuration file once you have rebooted into the newly-installed system.
7414 @xref{Using the Configuration System}, for an overview of the
7415 configuration file. The example configurations discussed in that
7416 section are available under @file{/etc/configuration} in the
7417 installation image. Thus, to get started with a system configuration
7418 providing a graphical display server (a ``desktop'' system), you can run
7419 something along these lines:
7423 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7424 # zile /mnt/etc/config.scm
7427 You should pay attention to what your configuration file contains, and
7432 Make sure the @code{grub-configuration} form refers to the device you
7433 want to install GRUB on.
7436 Be sure that your partition labels match the value of their respective
7437 @code{device} fields in your @code{file-system} configuration, assuming
7438 your @code{file-system} configuration sets the value of @code{title} to
7442 If there are encrypted or RAID partitions, make sure to add a
7443 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7446 Once you are done preparing the configuration file, the new system must
7447 be initialized (remember that the target root file system is mounted
7451 guix system init /mnt/etc/config.scm /mnt
7455 This copies all the necessary files and installs GRUB on
7456 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7457 more information, @pxref{Invoking guix system}. This command may trigger
7458 downloads or builds of missing packages, which can take some time.
7460 Once that command has completed---and hopefully succeeded!---you can run
7461 @command{reboot} and boot into the new system. The @code{root} password
7462 in the new system is initially empty; other users' passwords need to be
7463 initialized by running the @command{passwd} command as @code{root},
7464 unless your configuration specifies otherwise
7465 (@pxref{user-account-password, user account passwords}).
7467 @cindex upgrading GuixSD
7468 From then on, you can update GuixSD whenever you want by running
7469 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7470 then running @command{guix system reconfigure} to build a new system
7471 generation with the latest packages and services (@pxref{Invoking guix
7472 system}). We recommend doing that regularly so that your system
7473 includes the latest security updates (@pxref{Security Updates}).
7475 Join us on @code{#guix} on the Freenode IRC network or on
7476 @file{guix-devel@@gnu.org} to share your experience---good or not so
7479 @node Installing GuixSD in a VM
7480 @subsection Installing GuixSD in a Virtual Machine
7482 @cindex virtual machine, GuixSD installation
7483 If you'd like to install GuixSD in a virtual machine (VM) rather than on
7484 your beloved machine, this section is for you.
7486 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7487 disk image, follow these steps:
7491 First, retrieve and decompress the GuixSD installation image as
7492 described previously (@pxref{USB Stick Installation}).
7495 Create a disk image that will hold the installed system. To make a
7496 qcow2-formatted disk image, use the @command{qemu-img} command:
7499 qemu-img create -f qcow2 guixsd.img 5G
7502 This will create a 5GB file.
7505 Boot the USB installation image in an VM:
7508 qemu-system-x86_64 -m 1024 -smp 1 \
7509 -net user -net nic,model=virtio -boot menu=on \
7510 -drive file=guixsd.img \
7511 -drive file=guixsd-usb-install-@value{VERSION}.@var{system}
7514 In the VM console, quickly press the @kbd{F12} key to enter the boot
7515 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7519 You're now root in the VM, proceed with the installation process.
7520 @xref{Preparing for Installation}, and follow the instructions.
7523 Once installation is complete, you can boot the system that's on your
7524 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
7527 @node Building the Installation Image
7528 @subsection Building the Installation Image
7530 @cindex installation image
7531 The installation image described above was built using the @command{guix
7532 system} command, specifically:
7534 @c FIXME: 1G is too much; see <http://bugs.gnu.org/23077>.
7536 guix system disk-image --image-size=1G gnu/system/install.scm
7539 Have a look at @file{gnu/system/install.scm} in the source tree,
7540 and see also @ref{Invoking guix system} for more information
7541 about the installation image.
7543 @node System Configuration
7544 @section System Configuration
7546 @cindex system configuration
7547 The Guix System Distribution supports a consistent whole-system configuration
7548 mechanism. By that we mean that all aspects of the global system
7549 configuration---such as the available system services, timezone and
7550 locale settings, user accounts---are declared in a single place. Such
7551 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
7553 One of the advantages of putting all the system configuration under the
7554 control of Guix is that it supports transactional system upgrades, and
7555 makes it possible to roll back to a previous system instantiation,
7556 should something go wrong with the new one (@pxref{Features}). Another
7557 advantage is that it makes it easy to replicate the exact same configuration
7558 across different machines, or at different points in time, without
7559 having to resort to additional administration tools layered on top of
7560 the own tools of the system.
7561 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
7563 This section describes this mechanism. First we focus on the system
7564 administrator's viewpoint---explaining how the system is configured and
7565 instantiated. Then we show how this mechanism can be extended, for
7566 instance to support new system services.
7569 * Using the Configuration System:: Customizing your GNU system.
7570 * operating-system Reference:: Detail of operating-system declarations.
7571 * File Systems:: Configuring file system mounts.
7572 * Mapped Devices:: Block device extra processing.
7573 * User Accounts:: Specifying user accounts.
7574 * Locales:: Language and cultural convention settings.
7575 * Services:: Specifying system services.
7576 * Setuid Programs:: Programs running with root privileges.
7577 * X.509 Certificates:: Authenticating HTTPS servers.
7578 * Name Service Switch:: Configuring libc's name service switch.
7579 * Initial RAM Disk:: Linux-Libre bootstrapping.
7580 * GRUB Configuration:: Configuring the boot loader.
7581 * Invoking guix system:: Instantiating a system configuration.
7582 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
7583 * Defining Services:: Adding new service definitions.
7586 @node Using the Configuration System
7587 @subsection Using the Configuration System
7589 The operating system is configured by providing an
7590 @code{operating-system} declaration in a file that can then be passed to
7591 the @command{guix system} command (@pxref{Invoking guix system}). A
7592 simple setup, with the default system services, the default Linux-Libre
7593 kernel, initial RAM disk, and boot loader looks like this:
7595 @findex operating-system
7597 @include os-config-bare-bones.texi
7600 This example should be self-describing. Some of the fields defined
7601 above, such as @code{host-name} and @code{bootloader}, are mandatory.
7602 Others, such as @code{packages} and @code{services}, can be omitted, in
7603 which case they get a default value.
7605 Below we discuss the effect of some of the most important fields
7606 (@pxref{operating-system Reference}, for details about all the available
7607 fields), and how to @dfn{instantiate} the operating system using
7608 @command{guix system}.
7610 @unnumberedsubsubsec Globally-Visible Packages
7612 @vindex %base-packages
7613 The @code{packages} field lists packages that will be globally visible
7614 on the system, for all user accounts---i.e., in every user's @code{PATH}
7615 environment variable---in addition to the per-user profiles
7616 (@pxref{Invoking guix package}). The @var{%base-packages} variable
7617 provides all the tools one would expect for basic user and administrator
7618 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
7619 the GNU Zile lightweight text editor, @command{find}, @command{grep},
7620 etc. The example above adds tcpdump to those, taken from the @code{(gnu
7621 packages admin)} module (@pxref{Package Modules}).
7623 @findex specification->package
7624 Referring to packages by variable name, like @var{tcpdump} above, has
7625 the advantage of being unambiguous; it also allows typos and such to be
7626 diagnosed right away as ``unbound variables''. The downside is that one
7627 needs to know which module defines which package, and to augment the
7628 @code{use-package-modules} line accordingly. To avoid that, one can use
7629 the @code{specification->package} procedure of the @code{(gnu packages)}
7630 module, which returns the best package for a given name or name and
7634 (use-modules (gnu packages))
7638 (packages (append (map specification->package
7639 '("tcpdump" "htop" "gnupg@@2.0"))
7643 @unnumberedsubsubsec System Services
7646 @vindex %base-services
7647 The @code{services} field lists @dfn{system services} to be made
7648 available when the system starts (@pxref{Services}).
7649 The @code{operating-system} declaration above specifies that, in
7650 addition to the basic services, we want the @command{lshd} secure shell
7651 daemon listening on port 2222 (@pxref{Networking Services,
7652 @code{lsh-service}}). Under the hood,
7653 @code{lsh-service} arranges so that @code{lshd} is started with the
7654 right command-line options, possibly with supporting configuration files
7655 generated as needed (@pxref{Defining Services}).
7657 @cindex customization, of services
7658 @findex modify-services
7659 Occasionally, instead of using the base services as is, you will want to
7660 customize them. To do this, use @code{modify-services} (@pxref{Service
7661 Reference, @code{modify-services}}) to modify the list.
7663 For example, suppose you want to modify @code{guix-daemon} and Mingetty
7664 (the console log-in) in the @var{%base-services} list (@pxref{Base
7665 Services, @code{%base-services}}). To do that, you can write the
7666 following in your operating system declaration:
7669 (define %my-services
7670 ;; My very own list of services.
7671 (modify-services %base-services
7672 (guix-service-type config =>
7675 (use-substitutes? #f)
7676 (extra-options '("--gc-keep-derivations"))))
7677 (mingetty-service-type config =>
7678 (mingetty-configuration
7679 (inherit config)))))
7683 (services %my-services))
7686 This changes the configuration---i.e., the service parameters---of the
7687 @code{guix-service-type} instance, and that of all the
7688 @code{mingetty-service-type} instances in the @var{%base-services} list.
7689 Observe how this is accomplished: first, we arrange for the original
7690 configuration to be bound to the identifier @code{config} in the
7691 @var{body}, and then we write the @var{body} so that it evaluates to the
7692 desired configuration. In particular, notice how we use @code{inherit}
7693 to create a new configuration which has the same values as the old
7694 configuration, but with a few modifications.
7696 @cindex encrypted disk
7697 The configuration for a typical ``desktop'' usage, with an encrypted
7698 root partition, the X11 display
7699 server, GNOME and Xfce (users can choose which of these desktop
7700 environments to use at the log-in screen by pressing @kbd{F1}), network
7701 management, power management, and more, would look like this:
7704 @include os-config-desktop.texi
7707 A graphical environment with a choice of lightweight window managers
7708 instead of full-blown desktop environments would look like this:
7711 @include os-config-lightweight-desktop.texi
7714 @xref{Desktop Services}, for the exact list of services provided by
7715 @var{%desktop-services}. @xref{X.509 Certificates}, for background
7716 information about the @code{nss-certs} package that is used here.
7718 Again, @var{%desktop-services} is just a list of service objects. If
7719 you want to remove services from there, you can do so using the
7720 procedures for list filtering (@pxref{SRFI-1 Filtering and
7721 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
7722 following expression returns a list that contains all the services in
7723 @var{%desktop-services} minus the Avahi service:
7726 (remove (lambda (service)
7727 (eq? (service-kind service) avahi-service-type))
7731 @unnumberedsubsubsec Instantiating the System
7733 Assuming the @code{operating-system} declaration
7734 is stored in the @file{my-system-config.scm}
7735 file, the @command{guix system reconfigure my-system-config.scm} command
7736 instantiates that configuration, and makes it the default GRUB boot
7737 entry (@pxref{Invoking guix system}).
7739 The normal way to change the system configuration is by updating this
7740 file and re-running @command{guix system reconfigure}. One should never
7741 have to touch files in @file{/etc} or to run commands that modify the
7742 system state such as @command{useradd} or @command{grub-install}. In
7743 fact, you must avoid that since that would not only void your warranty
7744 but also prevent you from rolling back to previous versions of your
7745 system, should you ever need to.
7747 @cindex roll-back, of the operating system
7748 Speaking of roll-back, each time you run @command{guix system
7749 reconfigure}, a new @dfn{generation} of the system is created---without
7750 modifying or deleting previous generations. Old system generations get
7751 an entry in the GRUB boot menu, allowing you to boot them in case
7752 something went wrong with the latest generation. Reassuring, no? The
7753 @command{guix system list-generations} command lists the system
7754 generations available on disk. It is also possible to roll back the
7755 system via the commands @command{guix system roll-back} and
7756 @command{guix system switch-generation}.
7758 Although the command @command{guix system reconfigure} will not modify
7759 previous generations, must take care when the current generation is not
7760 the latest (e.g., after invoking @command{guix system roll-back}), since
7761 the operation might overwrite a later generation (@pxref{Invoking guix
7764 @unnumberedsubsubsec The Programming Interface
7766 At the Scheme level, the bulk of an @code{operating-system} declaration
7767 is instantiated with the following monadic procedure (@pxref{The Store
7770 @deffn {Monadic Procedure} operating-system-derivation os
7771 Return a derivation that builds @var{os}, an @code{operating-system}
7772 object (@pxref{Derivations}).
7774 The output of the derivation is a single directory that refers to all
7775 the packages, configuration files, and other supporting files needed to
7776 instantiate @var{os}.
7779 This procedure is provided by the @code{(gnu system)} module. Along
7780 with @code{(gnu services)} (@pxref{Services}), this module contains the
7781 guts of GuixSD. Make sure to visit it!
7784 @node operating-system Reference
7785 @subsection @code{operating-system} Reference
7787 This section summarizes all the options available in
7788 @code{operating-system} declarations (@pxref{Using the Configuration
7791 @deftp {Data Type} operating-system
7792 This is the data type representing an operating system configuration.
7793 By that, we mean all the global system configuration, not per-user
7794 configuration (@pxref{Using the Configuration System}).
7797 @item @code{kernel} (default: @var{linux-libre})
7798 The package object of the operating system kernel to use@footnote{Currently
7799 only the Linux-libre kernel is supported. In the future, it will be
7800 possible to use the GNU@tie{}Hurd.}.
7802 @item @code{kernel-arguments} (default: @code{'()})
7803 List of strings or gexps representing additional arguments to pass on
7804 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
7806 @item @code{bootloader}
7807 The system bootloader configuration object. @xref{GRUB Configuration}.
7809 @item @code{initrd} (default: @code{base-initrd})
7811 @cindex initial RAM disk
7812 A two-argument monadic procedure that returns an initial RAM disk for
7813 the Linux kernel. @xref{Initial RAM Disk}.
7815 @item @code{firmware} (default: @var{%base-firmware})
7817 List of firmware packages loadable by the operating system kernel.
7819 The default includes firmware needed for Atheros- and Broadcom-based
7820 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
7821 respectively). @xref{Hardware Considerations}, for more info on
7824 @item @code{host-name}
7827 @item @code{hosts-file}
7829 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
7830 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
7831 Reference Manual}). The default is a file with entries for
7832 @code{localhost} and @var{host-name}.
7834 @item @code{mapped-devices} (default: @code{'()})
7835 A list of mapped devices. @xref{Mapped Devices}.
7837 @item @code{file-systems}
7838 A list of file systems. @xref{File Systems}.
7840 @item @code{swap-devices} (default: @code{'()})
7841 @cindex swap devices
7842 A list of strings identifying devices or files to be used for ``swap
7843 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
7844 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
7845 It is possible to specify a swap file in a file system on a mapped
7846 device, provided that the necessary device mapping and file system are
7847 also specified. @xref{Mapped Devices} and @ref{File Systems}.
7849 @item @code{users} (default: @code{%base-user-accounts})
7850 @itemx @code{groups} (default: @var{%base-groups})
7851 List of user accounts and groups. @xref{User Accounts}.
7853 @item @code{skeletons} (default: @code{(default-skeletons)})
7854 A list target file name/file-like object tuples (@pxref{G-Expressions,
7855 file-like objects}). These are the skeleton files that will be added to
7856 the home directory of newly-created user accounts.
7858 For instance, a valid value may look like this:
7861 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
7862 (".guile" ,(plain-file "guile"
7863 "(use-modules (ice-9 readline))
7864 (activate-readline)")))
7867 @item @code{issue} (default: @var{%default-issue})
7868 A string denoting the contents of the @file{/etc/issue} file, which is
7869 displayed when users log in on a text console.
7871 @item @code{packages} (default: @var{%base-packages})
7872 The set of packages installed in the global profile, which is accessible
7873 at @file{/run/current-system/profile}.
7875 The default set includes core utilities and it is good practice to
7876 install non-core utilities in user profiles (@pxref{Invoking guix
7879 @item @code{timezone}
7880 A timezone identifying string---e.g., @code{"Europe/Paris"}.
7882 You can run the @command{tzselect} command to find out which timezone
7883 string corresponds to your region. Choosing an invalid timezone name
7884 causes @command{guix system} to fail.
7886 @item @code{locale} (default: @code{"en_US.utf8"})
7887 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
7888 Library Reference Manual}). @xref{Locales}, for more information.
7890 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
7891 The list of locale definitions to be compiled and that may be used at
7892 run time. @xref{Locales}.
7894 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
7895 The list of GNU@tie{}libc packages whose locale data and tools are used
7896 to build the locale definitions. @xref{Locales}, for compatibility
7897 considerations that justify this option.
7899 @item @code{name-service-switch} (default: @var{%default-nss})
7900 Configuration of the libc name service switch (NSS)---a
7901 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
7904 @item @code{services} (default: @var{%base-services})
7905 A list of service objects denoting system services. @xref{Services}.
7907 @item @code{pam-services} (default: @code{(base-pam-services)})
7909 @cindex pluggable authentication modules
7910 Linux @dfn{pluggable authentication module} (PAM) services.
7911 @c FIXME: Add xref to PAM services section.
7913 @item @code{setuid-programs} (default: @var{%setuid-programs})
7914 List of string-valued G-expressions denoting setuid programs.
7915 @xref{Setuid Programs}.
7917 @item @code{sudoers-file} (default: @var{%sudoers-specification})
7918 @cindex sudoers file
7919 The contents of the @file{/etc/sudoers} file as a file-like object
7920 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
7922 This file specifies which users can use the @command{sudo} command, what
7923 they are allowed to do, and what privileges they may gain. The default
7924 is that only @code{root} and members of the @code{wheel} group may use
7931 @subsection File Systems
7933 The list of file systems to be mounted is specified in the
7934 @code{file-systems} field of the operating system declaration
7935 (@pxref{Using the Configuration System}). Each file system is declared
7936 using the @code{file-system} form, like this:
7940 (mount-point "/home")
7941 (device "/dev/sda3")
7945 As usual, some of the fields are mandatory---those shown in the example
7946 above---while others can be omitted. These are described below.
7948 @deftp {Data Type} file-system
7949 Objects of this type represent file systems to be mounted. They
7950 contain the following members:
7954 This is a string specifying the type of the file system---e.g.,
7957 @item @code{mount-point}
7958 This designates the place where the file system is to be mounted.
7961 This names the ``source'' of the file system. By default it is the name
7962 of a node under @file{/dev}, but its meaning depends on the @code{title}
7963 field described below.
7965 @item @code{title} (default: @code{'device})
7966 This is a symbol that specifies how the @code{device} field is to be
7969 When it is the symbol @code{device}, then the @code{device} field is
7970 interpreted as a file name; when it is @code{label}, then @code{device}
7971 is interpreted as a partition label name; when it is @code{uuid},
7972 @code{device} is interpreted as a partition unique identifier (UUID).
7974 UUIDs may be converted from their string representation (as shown by the
7975 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
7976 @code{uuid} form expects 16-byte UUIDs as defined in
7977 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
7978 form of UUID used by the ext2 family of file systems and others, but it
7979 is different from ``UUIDs'' found in FAT file systems, for instance.},
7984 (mount-point "/home")
7987 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
7990 The @code{label} and @code{uuid} options offer a way to refer to disk
7991 partitions without having to hard-code their actual device
7992 name@footnote{Note that, while it is tempting to use
7993 @file{/dev/disk/by-uuid} and similar device names to achieve the same
7994 result, this is not recommended: These special device nodes are created
7995 by the udev daemon and may be unavailable at the time the device is
7998 However, when the source of a file system is a mapped device (@pxref{Mapped
7999 Devices}), its @code{device} field @emph{must} refer to the mapped
8000 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8001 @code{title} must be set to @code{'device}. This is required so that
8002 the system knows that mounting the file system depends on having the
8003 corresponding device mapping established.
8005 @item @code{flags} (default: @code{'()})
8006 This is a list of symbols denoting mount flags. Recognized flags
8007 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8008 access to special files), @code{no-suid} (ignore setuid and setgid
8009 bits), and @code{no-exec} (disallow program execution.)
8011 @item @code{options} (default: @code{#f})
8012 This is either @code{#f}, or a string denoting mount options.
8014 @item @code{mount?} (default: @code{#t})
8015 This value indicates whether to automatically mount the file system when
8016 the system is brought up. When set to @code{#f}, the file system gets
8017 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8018 is not automatically mounted.
8020 @item @code{needed-for-boot?} (default: @code{#f})
8021 This Boolean value indicates whether the file system is needed when
8022 booting. If that is true, then the file system is mounted when the
8023 initial RAM disk (initrd) is loaded. This is always the case, for
8024 instance, for the root file system.
8026 @item @code{check?} (default: @code{#t})
8027 This Boolean indicates whether the file system needs to be checked for
8028 errors before being mounted.
8030 @item @code{create-mount-point?} (default: @code{#f})
8031 When true, the mount point is created if it does not exist yet.
8033 @item @code{dependencies} (default: @code{'()})
8034 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8035 representing file systems that must be mounted or mapped devices that
8036 must be opened before (and unmounted or closed after) this one.
8038 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8039 a dependency of @file{/sys/fs/cgroup/cpu} and
8040 @file{/sys/fs/cgroup/memory}.
8042 Another example is a file system that depends on a mapped device, for
8043 example for an encrypted partition (@pxref{Mapped Devices}).
8047 The @code{(gnu system file-systems)} exports the following useful
8050 @defvr {Scheme Variable} %base-file-systems
8051 These are essential file systems that are required on normal systems,
8052 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8053 below.) Operating system declarations should always contain at least
8057 @defvr {Scheme Variable} %pseudo-terminal-file-system
8058 This is the file system to be mounted as @file{/dev/pts}. It supports
8059 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8060 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8061 Manual}). Pseudo-terminals are used by terminal emulators such as
8065 @defvr {Scheme Variable} %shared-memory-file-system
8066 This file system is mounted as @file{/dev/shm} and is used to support
8067 memory sharing across processes (@pxref{Memory-mapped I/O,
8068 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8071 @defvr {Scheme Variable} %immutable-store
8072 This file system performs a read-only ``bind mount'' of
8073 @file{/gnu/store}, making it read-only for all the users including
8074 @code{root}. This prevents against accidental modification by software
8075 running as @code{root} or by system administrators.
8077 The daemon itself is still able to write to the store: it remounts it
8078 read-write in its own ``name space.''
8081 @defvr {Scheme Variable} %binary-format-file-system
8082 The @code{binfmt_misc} file system, which allows handling of arbitrary
8083 executable file types to be delegated to user space. This requires the
8084 @code{binfmt.ko} kernel module to be loaded.
8087 @defvr {Scheme Variable} %fuse-control-file-system
8088 The @code{fusectl} file system, which allows unprivileged users to mount
8089 and unmount user-space FUSE file systems. This requires the
8090 @code{fuse.ko} kernel module to be loaded.
8093 @node Mapped Devices
8094 @subsection Mapped Devices
8096 @cindex device mapping
8097 @cindex mapped devices
8098 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8099 such as a hard disk partition, can be @dfn{mapped} into another device,
8100 usually in @code{/dev/mapper/},
8101 with additional processing over the data that flows through
8102 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8103 concept of a ``mapped device'' and that of a file system: both boil down
8104 to @emph{translating} input/output operations made on a file to
8105 operations on its backing store. Thus, the Hurd implements mapped
8106 devices, like file systems, using the generic @dfn{translator} mechanism
8107 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8108 typical example is encryption device mapping: all writes to the mapped
8109 device are encrypted, and all reads are deciphered, transparently.
8110 Guix extends this notion by considering any device or set of devices that
8111 are @dfn{transformed} in some way to create a new device; for instance,
8112 RAID devices are obtained by @dfn{assembling} several other devices, such
8113 as hard disks or partitions, into a new one that behaves as one partition.
8114 Other examples, not yet implemented, are LVM logical volumes.
8116 Mapped devices are declared using the @code{mapped-device} form,
8117 defined as follows; for examples, see below.
8119 @deftp {Data Type} mapped-device
8120 Objects of this type represent device mappings that will be made when
8121 the system boots up.
8125 This is either a string specifying the name of the block device to be mapped,
8126 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8127 need to be assembled for creating a new one.
8130 This string specifies the name of the resulting mapped device. For
8131 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8132 specifying @code{"my-partition"} leads to the creation of
8133 the @code{"/dev/mapper/my-partition"} device.
8134 For RAID devices of type @code{raid-device-mapping}, the full device name
8135 such as @code{"/dev/md0"} needs to be given.
8138 This must be a @code{mapped-device-kind} object, which specifies how
8139 @var{source} is mapped to @var{target}.
8143 @defvr {Scheme Variable} luks-device-mapping
8144 This defines LUKS block device encryption using the @command{cryptsetup}
8145 command from the package with the same name. It relies on the
8146 @code{dm-crypt} Linux kernel module.
8149 @defvr {Scheme Variable} raid-device-mapping
8150 This defines a RAID device, which is assembled using the @code{mdadm}
8151 command from the package with the same name. It requires a Linux kernel
8152 module for the appropriate RAID level to be loaded, such as @code{raid456}
8153 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8156 @cindex disk encryption
8158 The following example specifies a mapping from @file{/dev/sda3} to
8159 @file{/dev/mapper/home} using LUKS---the
8160 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8161 standard mechanism for disk encryption.
8162 The @file{/dev/mapper/home}
8163 device can then be used as the @code{device} of a @code{file-system}
8164 declaration (@pxref{File Systems}).
8168 (source "/dev/sda3")
8170 (type luks-device-mapping))
8173 Alternatively, to become independent of device numbering, one may obtain
8174 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8178 cryptsetup luksUUID /dev/sda3
8181 and use it as follows:
8185 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8187 (type luks-device-mapping))
8190 @cindex swap encryption
8191 It is also desirable to encrypt swap space, since swap space may contain
8192 sensitive data. One way to accomplish that is to use a swap file in a
8193 file system on a device mapped via LUKS encryption. In this way, the
8194 swap file is encrypted because the entire device is encrypted.
8195 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8197 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8198 may be declared as follows:
8202 (source (list "/dev/sda1" "/dev/sdb1"))
8204 (type raid-device-mapping))
8207 The @file{/dev/md0} device can then be used as the @code{device} of a
8208 @code{file-system} declaration (@pxref{File Systems}).
8209 Note that the RAID level need not be given; it is chosen during the
8210 initial creation and formatting of the RAID device and is determined
8211 automatically later.
8215 @subsection User Accounts
8219 @cindex user accounts
8220 User accounts and groups are entirely managed through the
8221 @code{operating-system} declaration. They are specified with the
8222 @code{user-account} and @code{user-group} forms:
8228 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8230 "video" ;video devices such as webcams
8231 "cdrom")) ;the good ol' CD-ROM
8232 (comment "Bob's sister")
8233 (home-directory "/home/alice"))
8236 When booting or upon completion of @command{guix system reconfigure},
8237 the system ensures that only the user accounts and groups specified in
8238 the @code{operating-system} declaration exist, and with the specified
8239 properties. Thus, account or group creations or modifications made by
8240 directly invoking commands such as @command{useradd} are lost upon
8241 reconfiguration or reboot. This ensures that the system remains exactly
8244 @deftp {Data Type} user-account
8245 Objects of this type represent user accounts. The following members may
8250 The name of the user account.
8254 This is the name (a string) or identifier (a number) of the user group
8255 this account belongs to.
8257 @item @code{supplementary-groups} (default: @code{'()})
8258 Optionally, this can be defined as a list of group names that this
8261 @item @code{uid} (default: @code{#f})
8262 This is the user ID for this account (a number), or @code{#f}. In the
8263 latter case, a number is automatically chosen by the system when the
8266 @item @code{comment} (default: @code{""})
8267 A comment about the account, such as the account owner's full name.
8269 @item @code{home-directory}
8270 This is the name of the home directory for the account.
8272 @item @code{create-home-directory?} (default: @code{#t})
8273 Indicates whether the home directory of this account should be created
8274 if it does not exist yet.
8276 @item @code{shell} (default: Bash)
8277 This is a G-expression denoting the file name of a program to be used as
8278 the shell (@pxref{G-Expressions}).
8280 @item @code{system?} (default: @code{#f})
8281 This Boolean value indicates whether the account is a ``system''
8282 account. System accounts are sometimes treated specially; for instance,
8283 graphical login managers do not list them.
8285 @anchor{user-account-password}
8286 @item @code{password} (default: @code{#f})
8287 You would normally leave this field to @code{#f}, initialize user
8288 passwords as @code{root} with the @command{passwd} command, and then let
8289 users change it with @command{passwd}. Passwords set with
8290 @command{passwd} are of course preserved across reboot and
8293 If you @emph{do} want to have a preset password for an account, then
8294 this field must contain the encrypted password, as a string.
8295 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8296 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8297 Manual}, for information on Guile's @code{crypt} procedure.
8303 User group declarations are even simpler:
8306 (user-group (name "students"))
8309 @deftp {Data Type} user-group
8310 This type is for, well, user groups. There are just a few fields:
8314 The name of the group.
8316 @item @code{id} (default: @code{#f})
8317 The group identifier (a number). If @code{#f}, a new number is
8318 automatically allocated when the group is created.
8320 @item @code{system?} (default: @code{#f})
8321 This Boolean value indicates whether the group is a ``system'' group.
8322 System groups have low numerical IDs.
8324 @item @code{password} (default: @code{#f})
8325 What, user groups can have a password? Well, apparently yes. Unless
8326 @code{#f}, this field specifies the password of the group.
8331 For convenience, a variable lists all the basic user groups one may
8334 @defvr {Scheme Variable} %base-groups
8335 This is the list of basic user groups that users and/or packages expect
8336 to be present on the system. This includes groups such as ``root'',
8337 ``wheel'', and ``users'', as well as groups used to control access to
8338 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8341 @defvr {Scheme Variable} %base-user-accounts
8342 This is the list of basic system accounts that programs may expect to
8343 find on a GNU/Linux system, such as the ``nobody'' account.
8345 Note that the ``root'' account is not included here. It is a
8346 special-case and is automatically added whether or not it is specified.
8353 A @dfn{locale} defines cultural conventions for a particular language
8354 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8355 Reference Manual}). Each locale has a name that typically has the form
8356 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8357 @code{fr_LU.utf8} designates the locale for the French language, with
8358 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8360 @cindex locale definition
8361 Usually, you will want to specify the default locale for the machine
8362 using the @code{locale} field of the @code{operating-system} declaration
8363 (@pxref{operating-system Reference, @code{locale}}).
8365 The selected locale is automatically added to the @dfn{locale
8366 definitions} known to the system if needed, with its codeset inferred
8367 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8368 @code{UTF-8} codeset. Additional locale definitions can be specified in
8369 the @code{locale-definitions} slot of @code{operating-system}---this is
8370 useful, for instance, if the codeset could not be inferred from the
8371 locale name. The default set of locale definitions includes some widely
8372 used locales, but not all the available locales, in order to save space.
8374 For instance, to add the North Frisian locale for Germany, the value of
8378 (cons (locale-definition
8379 (name "fy_DE.utf8") (source "fy_DE"))
8380 %default-locale-definitions)
8383 Likewise, to save space, one might want @code{locale-definitions} to
8384 list only the locales that are actually used, as in:
8387 (list (locale-definition
8388 (name "ja_JP.eucjp") (source "ja_JP")
8389 (charset "EUC-JP")))
8393 The compiled locale definitions are available at
8394 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8395 version, which is the default location where the GNU@tie{}libc provided
8396 by Guix looks for locale data. This can be overridden using the
8397 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8398 @code{LOCPATH} and locale packages}).
8400 The @code{locale-definition} form is provided by the @code{(gnu system
8401 locale)} module. Details are given below.
8403 @deftp {Data Type} locale-definition
8404 This is the data type of a locale definition.
8409 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8410 Reference Manual}, for more information on locale names.
8413 The name of the source for that locale. This is typically the
8414 @code{@var{language}_@var{territory}} part of the locale name.
8416 @item @code{charset} (default: @code{"UTF-8"})
8417 The ``character set'' or ``code set'' for that locale,
8418 @uref{http://www.iana.org/assignments/character-sets, as defined by
8424 @defvr {Scheme Variable} %default-locale-definitions
8425 A list of commonly used UTF-8 locales, used as the default
8426 value of the @code{locale-definitions} field of @code{operating-system}
8430 @cindex normalized codeset in locale names
8431 These locale definitions use the @dfn{normalized codeset} for the part
8432 that follows the dot in the name (@pxref{Using gettextized software,
8433 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8434 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8438 @subsubsection Locale Data Compatibility Considerations
8440 @cindex incompatibility, of locale data
8441 @code{operating-system} declarations provide a @code{locale-libcs} field
8442 to specify the GNU@tie{}libc packages that are used to compile locale
8443 declarations (@pxref{operating-system Reference}). ``Why would I
8444 care?'', you may ask. Well, it turns out that the binary format of
8445 locale data is occasionally incompatible from one libc version to
8448 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8449 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8450 For instance, a program linked against libc version 2.21 is unable to
8451 read locale data produced with libc 2.22; worse, that program
8452 @emph{aborts} instead of simply ignoring the incompatible locale
8453 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8454 the incompatible locale data, which is already an improvement.}.
8455 Similarly, a program linked against libc 2.22 can read most, but not
8456 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8457 data is incompatible); thus calls to @code{setlocale} may fail, but
8458 programs will not abort.
8460 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8461 choose whether and when to upgrade software in their profiles, and might
8462 be using a libc version different from the one the system administrator
8463 used to build the system-wide locale data.
8465 Fortunately, unprivileged users can also install their own locale data
8466 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8467 @code{GUIX_LOCPATH} and locale packages}).
8469 Still, it is best if the system-wide locale data at
8470 @file{/run/current-system/locale} is built for all the libc versions
8471 actually in use on the system, so that all the programs can access
8472 it---this is especially crucial on a multi-user system. To do that, the
8473 administrator can specify several libc packages in the
8474 @code{locale-libcs} field of @code{operating-system}:
8477 (use-package-modules base)
8481 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8484 This example would lead to a system containing locale definitions for
8485 both libc 2.21 and the current version of libc in
8486 @file{/run/current-system/locale}.
8490 @subsection Services
8492 @cindex system services
8493 An important part of preparing an @code{operating-system} declaration is
8494 listing @dfn{system services} and their configuration (@pxref{Using the
8495 Configuration System}). System services are typically daemons launched
8496 when the system boots, or other actions needed at that time---e.g.,
8497 configuring network access.
8499 GuixSD has a broad definition of ``service'' (@pxref{Service
8500 Composition}), but many services are managed by the GNU@tie{}Shepherd
8501 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8502 command allows you to list the available services, show their status,
8503 start and stop them, or do other specific operations (@pxref{Jump
8504 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8510 The above command, run as @code{root}, lists the currently defined
8511 services. The @command{herd doc} command shows a synopsis of the given
8516 Run libc's name service cache daemon (nscd).
8519 The @command{start}, @command{stop}, and @command{restart} sub-commands
8520 have the effect you would expect. For instance, the commands below stop
8521 the nscd service and restart the Xorg display server:
8525 Service nscd has been stopped.
8526 # herd restart xorg-server
8527 Service xorg-server has been stopped.
8528 Service xorg-server has been started.
8531 The following sections document the available services, starting with
8532 the core services, that may be used in an @code{operating-system}
8536 * Base Services:: Essential system services.
8537 * Scheduled Job Execution:: The mcron service.
8538 * Log Rotation:: The rottlog service.
8539 * Networking Services:: Network setup, SSH daemon, etc.
8540 * X Window:: Graphical display.
8541 * Printing Services:: Local and remote printer support.
8542 * Desktop Services:: D-Bus and desktop services.
8543 * Database Services:: SQL databases.
8544 * Mail Services:: IMAP, POP3, SMTP, and all that.
8545 * Messaging Services:: Messaging services.
8546 * Kerberos Services:: Kerberos services.
8547 * Web Services:: Web servers.
8548 * VPN Services:: VPN daemons.
8549 * Network File System:: NFS related services.
8550 * Continuous Integration:: The Cuirass service.
8551 * Power management Services:: The TLP tool.
8552 * Miscellaneous Services:: Other services.
8556 @subsubsection Base Services
8558 The @code{(gnu services base)} module provides definitions for the basic
8559 services that one expects from the system. The services exported by
8560 this module are listed below.
8562 @defvr {Scheme Variable} %base-services
8563 This variable contains a list of basic services (@pxref{Service Types
8564 and Services}, for more information on service objects) one would
8565 expect from the system: a login service (mingetty) on each tty, syslogd,
8566 the libc name service cache daemon (nscd), the udev device manager, and
8569 This is the default value of the @code{services} field of
8570 @code{operating-system} declarations. Usually, when customizing a
8571 system, you will want to append services to @var{%base-services}, like
8575 (cons* (avahi-service) (lsh-service) %base-services)
8579 @defvr {Scheme Variable} special-files-service-type
8580 This is the service that sets up ``special files'' such as
8581 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
8583 The value associated with @code{special-files-service-type} services
8584 must be a list of tuples where the first element is the ``special file''
8585 and the second element is its target. By default it is:
8587 @cindex @file{/bin/sh}
8588 @cindex @file{sh}, in @file{/bin}
8590 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
8593 @cindex @file{/usr/bin/env}
8594 @cindex @file{env}, in @file{/usr/bin}
8595 If you want to add, say, @code{/usr/bin/env} to your system, you can
8599 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
8600 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
8603 Since this is part of @code{%base-services}, you can use
8604 @code{modify-services} to customize the set of special files
8605 (@pxref{Service Reference, @code{modify-services}}). But the simple way
8606 to add a special file is @i{via} the @code{extra-special-file} procedure
8610 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
8611 Use @var{target} as the ``special file'' @var{file}.
8613 For example, adding the following lines to the @code{services} field of
8614 your operating system declaration leads to a @file{/usr/bin/env}
8618 (extra-special-file "/usr/bin/env"
8619 (file-append coreutils "/bin/env"))
8623 @deffn {Scheme Procedure} host-name-service @var{name}
8624 Return a service that sets the host name to @var{name}.
8627 @deffn {Scheme Procedure} login-service @var{config}
8628 Return a service to run login according to @var{config}, a
8629 @code{<login-configuration>} object, which specifies the message of the day,
8633 @deftp {Data Type} login-configuration
8634 This is the data type representing the configuration of login.
8639 @cindex message of the day
8640 A file-like object containing the ``message of the day''.
8642 @item @code{allow-empty-passwords?} (default: @code{#t})
8643 Allow empty passwords by default so that first-time users can log in when
8644 the 'root' account has just been created.
8649 @deffn {Scheme Procedure} mingetty-service @var{config}
8650 Return a service to run mingetty according to @var{config}, a
8651 @code{<mingetty-configuration>} object, which specifies the tty to run, among
8655 @deftp {Data Type} mingetty-configuration
8656 This is the data type representing the configuration of Mingetty, which
8657 provides the default implementation of virtual console log-in.
8662 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
8664 @item @code{auto-login} (default: @code{#f})
8665 When true, this field must be a string denoting the user name under
8666 which the system automatically logs in. When it is @code{#f}, a
8667 user name and password must be entered to log in.
8669 @item @code{login-program} (default: @code{#f})
8670 This must be either @code{#f}, in which case the default log-in program
8671 is used (@command{login} from the Shadow tool suite), or a gexp denoting
8672 the name of the log-in program.
8674 @item @code{login-pause?} (default: @code{#f})
8675 When set to @code{#t} in conjunction with @var{auto-login}, the user
8676 will have to press a key before the log-in shell is launched.
8678 @item @code{mingetty} (default: @var{mingetty})
8679 The Mingetty package to use.
8684 @deffn {Scheme Procedure} agetty-service @var{config}
8685 Return a service to run agetty according to @var{config}, an
8686 @code{<agetty-configuration>} object, which specifies the tty to run,
8690 @deftp {Data Type} agetty-configuration
8691 This is the data type representing the configuration of agetty, which
8692 implements virtual and serial console log-in. See the @code{agetty(8)}
8693 man page for more information.
8698 The name of the console this agetty runs on, as a string---e.g.,
8699 @code{"ttyS0"}. This argument is mandatory.
8701 @item @code{baud-rate} (default: @code{#f})
8702 A string containing a comma-separated list of one or more baud rates, in
8705 @item @code{term} (default: @code{#f})
8706 A string containing the value used for the @code{TERM} environment
8709 @item @code{eight-bits?} (default: @code{#f})
8710 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
8713 @item @code{auto-login} (default: @code{#f})
8714 When passed a login name, as a string, the specified user will be logged
8715 in automatically without prompting for their login name or password.
8717 @item @code{no-reset?} (default: @code{#f})
8718 When @code{#t}, don't reset terminal cflags (control modes).
8720 @item @code{host} (default: @code{#f})
8721 This accepts a string containing the "login_host", which will be written
8722 into the @file{/var/run/utmpx} file.
8724 @item @code{remote?} (default: @code{#f})
8725 When set to @code{#t} in conjunction with @var{host}, this will add an
8726 @code{-r} fakehost option to the command line of the login program
8727 specified in @var{login-program}.
8729 @item @code{flow-control?} (default: @code{#f})
8730 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
8732 @item @code{no-issue?} (default: @code{#f})
8733 When set to @code{#t}, the contents of the @file{/etc/issue} file will
8734 not be displayed before presenting the login prompt.
8736 @item @code{init-string} (default: @code{#f})
8737 This accepts a string that will be sent to the tty or modem before
8738 sending anything else. It can be used to initialize a modem.
8740 @item @code{no-clear?} (default: @code{#f})
8741 When set to @code{#t}, agetty will not clear the screen before showing
8744 @item @code{login-program} (default: (file-append shadow "/bin/login"))
8745 This must be either a gexp denoting the name of a log-in program, or
8746 unset, in which case the default value is the @command{login} from the
8749 @item @code{local-line} (default: @code{#f})
8750 Control the CLOCAL line flag. This accepts one of three symbols as
8751 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
8752 the default value chosen by agetty is @code{'auto}.
8754 @item @code{extract-baud?} (default: @code{#f})
8755 When set to @code{#t}, instruct agetty to try to extract the baud rate
8756 from the status messages produced by certain types of modems.
8758 @item @code{skip-login?} (default: @code{#f})
8759 When set to @code{#t}, do not prompt the user for a login name. This
8760 can be used with @var{login-program} field to use non-standard login
8763 @item @code{no-newline?} (default: @code{#f})
8764 When set to @code{#t}, do not print a newline before printing the
8765 @file{/etc/issue} file.
8767 @c Is this dangerous only when used with login-program, or always?
8768 @item @code{login-options} (default: @code{#f})
8769 This option accepts a string containing options that are passed to the
8770 login program. When used with the @var{login-program}, be aware that a
8771 malicious user could try to enter a login name containing embedded
8772 options that could be parsed by the login program.
8774 @item @code{login-pause} (default: @code{#f})
8775 When set to @code{#t}, wait for any key before showing the login prompt.
8776 This can be used in conjunction with @var{auto-login} to save memory by
8777 lazily spawning shells.
8779 @item @code{chroot} (default: @code{#f})
8780 Change root to the specified directory. This option accepts a directory
8783 @item @code{hangup?} (default: @code{#f})
8784 Use the Linux system call @code{vhangup} to do a virtual hangup of the
8787 @item @code{keep-baud?} (default: @code{#f})
8788 When set to @code{#t}, try to keep the existing baud rate. The baud
8789 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
8792 @item @code{timeout} (default: @code{#f})
8793 When set to an integer value, terminate if no user name could be read
8794 within @var{timeout} seconds.
8796 @item @code{detect-case?} (default: @code{#f})
8797 When set to @code{#t}, turn on support for detecting an uppercase-only
8798 terminal. This setting will detect a login name containing only
8799 uppercase letters as indicating an uppercase-only terminal and turn on
8800 some upper-to-lower case conversions. Note that this will not support
8803 @item @code{wait-cr?} (default: @code{#f})
8804 When set to @code{#t}, wait for the user or modem to send a
8805 carriage-return or linefeed character before displaying
8806 @file{/etc/issue} or login prompt. This is typically used with the
8807 @var{init-string} option.
8809 @item @code{no-hints?} (default: @code{#f})
8810 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
8813 @item @code{no-hostname?} (default: @code{#f})
8814 By default, the hostname is printed. When this option is set to
8815 @code{#t}, no hostname will be shown at all.
8817 @item @code{long-hostname?} (default: @code{#f})
8818 By default, the hostname is only printed until the first dot. When this
8819 option is set to @code{#t}, the fully qualified hostname by
8820 @code{gethostname} or @code{getaddrinfo} is shown.
8822 @item @code{erase-characters} (default: @code{#f})
8823 This option accepts a string of additional characters that should be
8824 interpreted as backspace when the user types their login name.
8826 @item @code{kill-characters} (default: @code{#f})
8827 This option accepts a string that should be interpreted to mean "ignore
8828 all previous characters" (also called a "kill" character) when the types
8831 @item @code{chdir} (default: @code{#f})
8832 This option accepts, as a string, a directory path that will be changed
8835 @item @code{delay} (default: @code{#f})
8836 This options accepts, as an integer, the number of seconds to sleep
8837 before opening the tty and displaying the login prompt.
8839 @item @code{nice} (default: @code{#f})
8840 This option accepts, as an integer, the nice value with which to run the
8841 @command{login} program.
8843 @item @code{extra-options} (default: @code{'()})
8844 This option provides an "escape hatch" for the user to provide arbitrary
8845 command-line arguments to @command{agetty} as a list of strings.
8850 @deffn {Scheme Procedure} kmscon-service-type @var{config}
8851 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
8852 according to @var{config}, a @code{<kmscon-configuration>} object, which
8853 specifies the tty to run, among other things.
8856 @deftp {Data Type} kmscon-configuration
8857 This is the data type representing the configuration of Kmscon, which
8858 implements virtual console log-in.
8862 @item @code{virtual-terminal}
8863 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
8865 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
8866 A gexp denoting the name of the log-in program. The default log-in program is
8867 @command{login} from the Shadow tool suite.
8869 @item @code{login-arguments} (default: @code{'("-p")})
8870 A list of arguments to pass to @command{login}.
8872 @item @code{hardware-acceleration?} (default: #f)
8873 Whether to use hardware acceleration.
8875 @item @code{kmscon} (default: @var{kmscon})
8876 The Kmscon package to use.
8881 @cindex name service cache daemon
8883 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
8884 [#:name-services '()]
8885 Return a service that runs the libc name service cache daemon (nscd) with the
8886 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
8887 Service Switch}, for an example.
8890 @defvr {Scheme Variable} %nscd-default-configuration
8891 This is the default @code{<nscd-configuration>} value (see below) used
8892 by @code{nscd-service}. It uses the caches defined by
8893 @var{%nscd-default-caches}; see below.
8896 @deftp {Data Type} nscd-configuration
8897 This is the data type representing the name service cache daemon (nscd)
8902 @item @code{name-services} (default: @code{'()})
8903 List of packages denoting @dfn{name services} that must be visible to
8904 the nscd---e.g., @code{(list @var{nss-mdns})}.
8906 @item @code{glibc} (default: @var{glibc})
8907 Package object denoting the GNU C Library providing the @command{nscd}
8910 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
8911 Name of the nscd log file. This is where debugging output goes when
8912 @code{debug-level} is strictly positive.
8914 @item @code{debug-level} (default: @code{0})
8915 Integer denoting the debugging levels. Higher numbers mean that more
8916 debugging output is logged.
8918 @item @code{caches} (default: @var{%nscd-default-caches})
8919 List of @code{<nscd-cache>} objects denoting things to be cached; see
8925 @deftp {Data Type} nscd-cache
8926 Data type representing a cache database of nscd and its parameters.
8930 @item @code{database}
8931 This is a symbol representing the name of the database to be cached.
8932 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
8933 @code{services}, which designate the corresponding NSS database
8934 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
8936 @item @code{positive-time-to-live}
8937 @itemx @code{negative-time-to-live} (default: @code{20})
8938 A number representing the number of seconds during which a positive or
8939 negative lookup result remains in cache.
8941 @item @code{check-files?} (default: @code{#t})
8942 Whether to check for updates of the files corresponding to
8945 For instance, when @var{database} is @code{hosts}, setting this flag
8946 instructs nscd to check for updates in @file{/etc/hosts} and to take
8949 @item @code{persistent?} (default: @code{#t})
8950 Whether the cache should be stored persistently on disk.
8952 @item @code{shared?} (default: @code{#t})
8953 Whether the cache should be shared among users.
8955 @item @code{max-database-size} (default: 32@tie{}MiB)
8956 Maximum size in bytes of the database cache.
8958 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
8959 @c settings, so leave them out.
8964 @defvr {Scheme Variable} %nscd-default-caches
8965 List of @code{<nscd-cache>} objects used by default by
8966 @code{nscd-configuration} (see above).
8968 It enables persistent and aggressive caching of service and host name
8969 lookups. The latter provides better host name lookup performance,
8970 resilience in the face of unreliable name servers, and also better
8971 privacy---often the result of host name lookups is in local cache, so
8972 external name servers do not even need to be queried.
8975 @anchor{syslog-configuration-type}
8978 @deftp {Data Type} syslog-configuration
8979 This data type represents the configuration of the syslog daemon.
8982 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
8983 The syslog daemon to use.
8985 @item @code{config-file} (default: @code{%default-syslog.conf})
8986 The syslog configuration file to use.
8991 @anchor{syslog-service}
8993 @deffn {Scheme Procedure} syslog-service @var{config}
8994 Return a service that runs a syslog daemon according to @var{config}.
8996 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
8997 information on the configuration file syntax.
9000 @anchor{guix-configuration-type}
9001 @deftp {Data Type} guix-configuration
9002 This data type represents the configuration of the Guix build daemon.
9003 @xref{Invoking guix-daemon}, for more information.
9006 @item @code{guix} (default: @var{guix})
9007 The Guix package to use.
9009 @item @code{build-group} (default: @code{"guixbuild"})
9010 Name of the group for build user accounts.
9012 @item @code{build-accounts} (default: @code{10})
9013 Number of build user accounts to create.
9015 @item @code{authorize-key?} (default: @code{#t})
9016 @cindex substitutes, authorization thereof
9017 Whether to authorize the substitute keys listed in
9018 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9019 (@pxref{Substitutes}).
9021 @vindex %default-authorized-guix-keys
9022 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9023 The list of authorized key files for archive imports, as a list of
9024 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9025 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9027 @item @code{use-substitutes?} (default: @code{#t})
9028 Whether to use substitutes.
9030 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9031 The list of URLs where to look for substitutes by default.
9033 @item @code{extra-options} (default: @code{'()})
9034 List of extra command-line options for @command{guix-daemon}.
9036 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9037 File where @command{guix-daemon}'s standard output and standard error
9040 @item @code{lsof} (default: @var{lsof})
9041 The lsof package to use.
9043 @item @code{http-proxy} (default: @code{#f})
9044 The HTTP proxy used for downloading fixed-output derivations and
9047 @item @code{tmpdir} (default: @code{#f})
9048 A directory path where the @command{guix-daemon} will perform builds.
9053 @deffn {Scheme Procedure} guix-service @var{config}
9054 Return a service that runs the Guix build daemon according to
9058 @deffn {Scheme Procedure} udev-service [#:udev udev]
9059 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9062 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9063 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9067 @defvr {Scheme Variable} %random-seed-file
9068 This is the name of the file where some random bytes are saved by
9069 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9070 It defaults to @file{/var/lib/random-seed}.
9075 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9076 @cindex keyboard layout
9077 Return a service to load console keymaps from @var{files} using
9078 @command{loadkeys} command. Most likely, you want to load some default
9079 keymap, which can be done like this:
9082 (console-keymap-service "dvorak")
9085 Or, for example, for a Swedish keyboard, you may need to combine
9086 the following keymaps:
9088 (console-keymap-service "se-lat6" "se-fi-lat6")
9091 Also you can specify a full file name (or file names) of your keymap(s).
9092 See @code{man loadkeys} for details.
9098 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9100 Run @var{gpm}, the general-purpose mouse daemon, with the given
9101 command-line @var{options}. GPM allows users to use the mouse in the console,
9102 notably to select, copy, and paste text. The default value of @var{options}
9103 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9105 This service is not part of @var{%base-services}.
9108 @anchor{guix-publish-service-type}
9109 @deffn {Scheme Variable} guix-publish-service-type
9110 This is the service type for @command{guix publish} (@pxref{Invoking
9111 guix publish}). Its value must be a @code{guix-configuration}
9112 object, as described below.
9114 This assumes that @file{/etc/guix} already contains a signing key pair as
9115 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9116 archive}). If that is not the case, the service will fail to start.
9119 @deftp {Data Type} guix-publish-configuration
9120 Data type representing the configuration of the @code{guix publish}
9124 @item @code{guix} (default: @code{guix})
9125 The Guix package to use.
9127 @item @code{port} (default: @code{80})
9128 The TCP port to listen for connections.
9130 @item @code{host} (default: @code{"localhost"})
9131 The host (and thus, network interface) to listen to. Use
9132 @code{"0.0.0.0"} to listen on all the network interfaces.
9134 @item @code{compression-level} (default: @code{3})
9135 The gzip compression level at which substitutes are compressed. Use
9136 @code{0} to disable compression altogether, and @code{9} to get the best
9137 compression ratio at the expense of increased CPU usage.
9139 @item @code{nar-path} (default: @code{"nar"})
9140 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9141 publish, @code{--nar-path}}, for details.
9145 @anchor{rngd-service}
9146 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9147 [#:device "/dev/hwrng"]
9148 Return a service that runs the @command{rngd} program from @var{rng-tools}
9149 to add @var{device} to the kernel's entropy pool. The service will fail if
9150 @var{device} does not exist.
9153 @anchor{pam-limits-service}
9154 @cindex session limits
9157 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9159 Return a service that installs a configuration file for the
9160 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9161 @code{pam_limits} module}. The procedure optionally takes a list of
9162 @code{pam-limits-entry} values, which can be used to specify
9163 @code{ulimit} limits and nice priority limits to user sessions.
9165 The following limits definition sets two hard and soft limits for all
9166 login sessions of users in the @code{realtime} group:
9171 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9172 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9175 The first entry increases the maximum realtime priority for
9176 non-privileged processes; the second entry lifts any restriction of the
9177 maximum address space that can be locked in memory. These settings are
9178 commonly used for real-time audio systems.
9181 @node Scheduled Job Execution
9182 @subsubsection Scheduled Job Execution
9186 @cindex scheduling jobs
9187 The @code{(gnu services mcron)} module provides an interface to
9188 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9189 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9190 Unix @command{cron} daemon; the main difference is that it is
9191 implemented in Guile Scheme, which provides a lot of flexibility when
9192 specifying the scheduling of jobs and their actions.
9194 The example below defines an operating system that runs the
9195 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9196 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9197 well as the @command{mkid} command on behalf of an unprivileged user
9198 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9199 gexps to introduce job definitions that are passed to mcron
9200 (@pxref{G-Expressions}).
9203 (use-modules (guix) (gnu) (gnu services mcron))
9204 (use-package-modules base idutils)
9206 (define updatedb-job
9207 ;; Run 'updatedb' at 3AM every day. Here we write the
9208 ;; job's action as a Scheme procedure.
9209 #~(job '(next-hour '(3))
9211 (execl (string-append #$findutils "/bin/updatedb")
9213 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9215 (define garbage-collector-job
9216 ;; Collect garbage 5 minutes after midnight every day.
9217 ;; The job's action is a shell command.
9218 #~(job "5 0 * * *" ;Vixie cron syntax
9222 ;; Update the index database as user "charlie" at 12:15PM
9223 ;; and 19:15PM. This runs from the user's home directory.
9224 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9225 (string-append #$idutils "/bin/mkid src")
9230 (services (cons (mcron-service (list garbage-collector-job
9236 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9237 for more information on mcron job specifications. Below is the
9238 reference of the mcron service.
9240 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9241 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9242 list of gexps denoting mcron job specifications.
9244 This is a shorthand for:
9246 (service mcron-service-type
9247 (mcron-configuration (mcron mcron) (jobs jobs)))
9251 @defvr {Scheme Variable} mcron-service-type
9252 This is the type of the @code{mcron} service, whose value is an
9253 @code{mcron-configuration} object.
9255 This service type can be the target of a service extension that provides
9256 it additional job specifications (@pxref{Service Composition}). In
9257 other words, it is possible to define services that provide additional
9261 @deftp {Data Type} mcron-configuration
9262 Data type representing the configuration of mcron.
9265 @item @code{mcron} (default: @var{mcron2})
9266 The mcron package to use.
9269 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9270 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9271 specifications,, mcron, GNU@tie{}mcron}).
9277 @subsubsection Log Rotation
9280 @cindex log rotation
9282 Log files such as those found in @file{/var/log} tend to grow endlessly,
9283 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9284 their contents in separate files, possibly compressed. The @code{(gnu
9285 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9286 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9288 The example below defines an operating system that provides log rotation
9289 with the default settings.
9292 (use-modules (guix) (gnu))
9293 (use-service-modules admin mcron)
9294 (use-package-modules base idutils)
9298 (services (cons* (mcron-service)
9299 (service rottlog-service-type)
9303 @defvr {Scheme Variable} rottlog-service-type
9304 This is the type of the Rottlog service, whose value is a
9305 @code{rottlog-configuration} object.
9307 This service type can define mcron jobs (@pxref{Scheduled Job
9308 Execution}) to run the rottlog service.
9311 @deftp {Data Type} rottlog-configuration
9312 Data type representing the configuration of rottlog.
9315 @item @code{rottlog} (default: @code{rottlog})
9316 The Rottlog package to use.
9318 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9319 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9320 rottlog, GNU Rot[t]log Manual}).
9322 @item @code{periodic-rotations} (default: @code{`(("weekly" %default-rotations))})
9323 A list of Rottlog period-name/period-config tuples.
9325 For example, taking an example from the Rottlog manual (@pxref{Period
9326 Related File Examples,,, rottlog, GNU Rot[t]log Manual}), a valid tuple
9330 ("daily" ,(plain-file "daily"
9332 /var/log/apache/* @{
9333 storedir apache-archives
9341 This is a list of gexps where each gexp corresponds to an mcron job
9342 specification (@pxref{Scheduled Job Execution}).
9346 @defvr {Scheme Variable} %default-rotations
9347 Specifies weekly rotation of @var{%rotated-files} and
9348 @code{"/var/log/shepherd.log"}.
9351 @defvr {Scheme Variable} %rotated-files
9352 The list of syslog-controlled files to be rotated. By default it is:
9353 @code{'("/var/log/messages" "/var/log/secure")}.
9356 @node Networking Services
9357 @subsubsection Networking Services
9359 The @code{(gnu services networking)} module provides services to configure
9360 the network interface.
9362 @cindex DHCP, networking service
9363 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9364 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9365 Protocol (DHCP) client, on all the non-loopback network interfaces.
9368 @defvr {Scheme Variable} static-networking-service-type
9369 This is the type for statically-configured network interfaces.
9370 @c TODO Document <static-networking> data structures.
9373 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9374 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9375 Return a service that starts @var{interface} with address @var{ip}. If
9376 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9377 it must be a string specifying the default network gateway.
9379 This procedure can be called several times, one for each network
9380 interface of interest. Behind the scenes what it does is extend
9381 @code{static-networking-service-type} with additional network interfaces
9388 @cindex network management
9389 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9390 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9391 management daemon that aims to simplify wired and wireless networking.
9393 This service adds the @var{wicd} package to the global profile, providing
9394 several commands to interact with the daemon and configure networking:
9395 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
9396 and @command{wicd-curses} user interfaces.
9399 @cindex NetworkManager
9401 @defvr {Scheme Variable} network-manager-service-type
9402 This is the service type for the
9403 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
9404 service. The value for this service type is a
9405 @code{network-manager-configuration} record.
9408 @deftp {Data Type} network-manager-configuration
9409 Data type representing the configuration of NetworkManager.
9412 @item @code{network-manager} (default: @code{network-manager})
9413 The NetworkManager package to use.
9415 @item @code{dns} (default: @code{"default"})
9416 Processing mode for DNS, which affects how NetworkManager uses the
9417 @code{resolv.conf} configuration file.
9421 NetworkManager will update @code{resolv.conf} to reflect the nameservers
9422 provided by currently active connections.
9425 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
9426 using a "split DNS" configuration if you are connected to a VPN, and
9427 then update @code{resolv.conf} to point to the local nameserver.
9430 NetworkManager will not modify @code{resolv.conf}.
9437 @deffn {Scheme Variable} connman-service-type
9438 This is the service type to run @url{https://01.org/connman,Connman},
9439 a network connection manager.
9441 Its value must be an
9442 @code{connman-configuration} record as in this example:
9445 (service connman-service-type
9446 (connman-configuration
9450 See below for details about @code{connman-configuration}.
9453 @deftp {Data Type} connman-configuration
9454 Data Type representing the configuration of connman.
9457 @item @code{connman} (default: @var{connman})
9458 The connman package to use.
9460 @item @code{disable-vpn?} (default: @code{#f})
9461 When true, enable connman's vpn plugin.
9465 @cindex WPA Supplicant
9466 @defvr {Scheme Variable} wpa-supplicant-service-type
9467 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
9468 supplicant}, an authentication daemon required to authenticate against
9469 encrypted WiFi or ethernet networks. It is configured to listen for
9472 The value of this service is the @code{wpa-supplicant} package to use.
9473 Thus, it can be instantiated like this:
9476 (use-modules (gnu services networking))
9478 (service wpa-supplicant-service-type)
9483 @cindex real time clock
9484 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
9485 [#:servers @var{%ntp-servers}] @
9486 [#:allow-large-adjustment? #f]
9487 Return a service that runs the daemon from @var{ntp}, the
9488 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
9489 keep the system clock synchronized with that of @var{servers}.
9490 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
9491 make an initial adjustment of more than 1,000 seconds.
9494 @defvr {Scheme Variable} %ntp-servers
9495 List of host names used as the default NTP servers.
9499 @deffn {Scheme variable} inetd-service-type
9500 This service runs the @command{inetd} (@pxref{inetd invocation,,,
9501 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
9502 connections on internet sockets, and lazily starts the specified server
9503 program when a connection is made on one of these sockets.
9505 The value of this service is an @code{inetd-configuration} object. The
9506 following example configures the @command{inetd} daemon to provide the
9507 built-in @command{echo} service, as well as an smtp service which
9508 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
9509 gateway @code{hostname}:
9514 (inetd-configuration
9518 (socket-type 'stream)
9525 (socket-type 'stream)
9529 (program (file-append openssh "/bin/ssh"))
9531 '("ssh" "-qT" "-i" "/path/to/ssh_key"
9532 "-W" "smtp-server:25" "user@@hostname")))))
9535 See below for more details about @code{inetd-configuration}.
9538 @deftp {Data Type} inetd-configuration
9539 Data type representing the configuration of @command{inetd}.
9542 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
9543 The @command{inetd} executable to use.
9545 @item @code{entries} (default: @code{'()})
9546 A list of @command{inetd} service entries. Each entry should be created
9547 by the @code{inetd-entry} constructor.
9551 @deftp {Data Type} inetd-entry
9552 Data type representing an entry in the @command{inetd} configuration.
9553 Each entry corresponds to a socket where @command{inetd} will listen for
9557 @item @code{node} (default: @code{#f})
9558 Optional string, a comma-separated list of local addresses
9559 @command{inetd} should use when listening for this service.
9560 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
9561 description of all options.
9563 A string, the name must correspond to an entry in @code{/etc/services}.
9564 @item @code{socket-type}
9565 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
9567 @item @code{protocol}
9568 A string, must correspond to an entry in @code{/etc/protocols}.
9569 @item @code{wait?} (default: @code{#t})
9570 Whether @command{inetd} should wait for the server to exit before
9571 listening to new service requests.
9573 A string containing the user (and, optionally, group) name of the user
9574 as whom the server should run. The group name can be specified in a
9575 suffix, separated by a colon or period, i.e. @code{"user"},
9576 @code{"user:group"} or @code{"user.group"}.
9577 @item @code{program} (default: @code{"internal"})
9578 The server program which will serve the requests, or @code{"internal"}
9579 if @command{inetd} should use a built-in service.
9580 @item @code{arguments} (default: @code{'()})
9581 A list strings or file-like objects, which are the server program's
9582 arguments, starting with the zeroth argument, i.e. the name of the
9583 program itself. For @command{inetd}'s internal services, this entry
9584 must be @code{'()} or @code{'("internal")}.
9587 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
9588 detailed discussion of each configuration field.
9592 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
9593 Return a service to run the @uref{https://torproject.org, Tor} anonymous
9596 The daemon runs as the @code{tor} unprivileged user. It is passed
9597 @var{config-file}, a file-like object, with an additional @code{User tor} line
9598 and lines for hidden services added via @code{tor-hidden-service}. Run
9599 @command{man tor} for information about the configuration file.
9602 @cindex hidden service
9603 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
9604 Define a new Tor @dfn{hidden service} called @var{name} and implementing
9605 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
9608 '((22 "127.0.0.1:22")
9609 (80 "127.0.0.1:8080"))
9612 In this example, port 22 of the hidden service is mapped to local port 22, and
9613 port 80 is mapped to local port 8080.
9615 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
9616 the @file{hostname} file contains the @code{.onion} host name for the hidden
9619 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
9620 project's documentation} for more information.
9623 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
9624 [#:interface "127.0.0.1"] [#:port 6667] @
9625 [#:extra-settings ""]
9626 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
9627 acts as a gateway between IRC and chat networks.
9629 The daemon will listen to the interface corresponding to the IP address
9630 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
9631 local clients can connect, whereas @code{0.0.0.0} means that connections can
9632 come from any networking interface.
9634 In addition, @var{extra-settings} specifies a string to append to the
9638 Furthermore, @code{(gnu services ssh)} provides the following services.
9642 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
9643 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
9644 [#:allow-empty-passwords? #f] [#:root-login? #f] @
9645 [#:syslog-output? #t] [#:x11-forwarding? #t] @
9646 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
9647 [#:public-key-authentication? #t] [#:initialize? #t]
9648 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
9649 @var{host-key} must designate a file containing the host key, and readable
9652 When @var{daemonic?} is true, @command{lshd} will detach from the
9653 controlling terminal and log its output to syslogd, unless one sets
9654 @var{syslog-output?} to false. Obviously, it also makes lsh-service
9655 depend on existence of syslogd service. When @var{pid-file?} is true,
9656 @command{lshd} writes its PID to the file called @var{pid-file}.
9658 When @var{initialize?} is true, automatically create the seed and host key
9659 upon service activation if they do not exist yet. This may take long and
9660 require interaction.
9662 When @var{initialize?} is false, it is up to the user to initialize the
9663 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
9664 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
9665 basics,,, lsh, LSH Manual}).
9667 When @var{interfaces} is empty, lshd listens for connections on all the
9668 network interfaces; otherwise, @var{interfaces} must be a list of host names
9671 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
9672 passwords, and @var{root-login?} specifies whether to accept log-ins as
9675 The other options should be self-descriptive.
9680 @deffn {Scheme Variable} openssh-service-type
9681 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
9682 shell daemon, @command{sshd}. Its value must be an
9683 @code{openssh-configuration} record as in this example:
9686 (service openssh-service-type
9687 (openssh-configuration
9688 (x11-forwarding? #t)
9689 (permit-root-login 'without-password)))
9692 See below for details about @code{openssh-configuration}.
9695 @deftp {Data Type} openssh-configuration
9696 This is the configuration record for OpenSSH's @command{sshd}.
9699 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
9700 Name of the file where @command{sshd} writes its PID.
9702 @item @code{port-number} (default: @code{22})
9703 TCP port on which @command{sshd} listens for incoming connections.
9705 @item @code{permit-root-login} (default: @code{#f})
9706 This field determines whether and when to allow logins as root. If
9707 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
9708 If it's the symbol @code{'without-password}, then root logins are
9709 permitted but not with password-based authentication.
9711 @item @code{allow-empty-passwords?} (default: @code{#f})
9712 When true, users with empty passwords may log in. When false, they may
9715 @item @code{password-authentication?} (default: @code{#t})
9716 When true, users may log in with their password. When false, they have
9717 other authentication methods.
9719 @item @code{public-key-authentication?} (default: @code{#t})
9720 When true, users may log in using public key authentication. When
9721 false, users have to use other authentication method.
9723 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
9724 This is used only by protocol version 2.
9726 @item @code{x11-forwarding?} (default: @code{#f})
9727 When true, forwarding of X11 graphical client connections is
9728 enabled---in other words, @command{ssh} options @option{-X} and
9729 @option{-Y} will work.
9731 @item @code{challenge-response-authentication?} (default: @code{#f})
9732 Specifies whether challenge response authentication is allowed (e.g. via
9735 @item @code{use-pam?} (default: @code{#t})
9736 Enables the Pluggable Authentication Module interface. If set to
9737 @code{#t}, this will enable PAM authentication using
9738 @code{challenge-response-authentication?} and
9739 @code{password-authentication?}, in addition to PAM account and session
9740 module processing for all authentication types.
9742 Because PAM challenge response authentication usually serves an
9743 equivalent role to password authentication, you should disable either
9744 @code{challenge-response-authentication?} or
9745 @code{password-authentication?}.
9747 @item @code{print-last-log?} (default: @code{#t})
9748 Specifies whether @command{sshd} should print the date and time of the
9749 last user login when a user logs in interactively.
9751 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
9752 Configures external subsystems (e.g. file transfer daemon).
9754 This is a list of two-element lists, each of which containing the
9755 subsystem name and a command (with optional arguments) to execute upon
9758 The command @command{internal-sftp} implements an in-process SFTP
9759 server. Alternately, one can specify the @command{sftp-server} command:
9761 (service openssh-service-type
9762 (openssh-configuration
9764 '(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
9769 @deffn {Scheme Procedure} dropbear-service [@var{config}]
9770 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
9771 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
9774 For example, to specify a Dropbear service listening on port 1234, add
9775 this call to the operating system's @code{services} field:
9778 (dropbear-service (dropbear-configuration
9779 (port-number 1234)))
9783 @deftp {Data Type} dropbear-configuration
9784 This data type represents the configuration of a Dropbear SSH daemon.
9787 @item @code{dropbear} (default: @var{dropbear})
9788 The Dropbear package to use.
9790 @item @code{port-number} (default: 22)
9791 The TCP port where the daemon waits for incoming connections.
9793 @item @code{syslog-output?} (default: @code{#t})
9794 Whether to enable syslog output.
9796 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
9797 File name of the daemon's PID file.
9799 @item @code{root-login?} (default: @code{#f})
9800 Whether to allow @code{root} logins.
9802 @item @code{allow-empty-passwords?} (default: @code{#f})
9803 Whether to allow empty passwords.
9805 @item @code{password-authentication?} (default: @code{#t})
9806 Whether to enable password-based authentication.
9810 @defvr {Scheme Variable} %facebook-host-aliases
9811 This variable contains a string for use in @file{/etc/hosts}
9812 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
9813 line contains a entry that maps a known server name of the Facebook
9814 on-line service---e.g., @code{www.facebook.com}---to the local
9815 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
9817 This variable is typically used in the @code{hosts-file} field of an
9818 @code{operating-system} declaration (@pxref{operating-system Reference,
9819 @file{/etc/hosts}}):
9822 (use-modules (gnu) (guix))
9825 (host-name "mymachine")
9828 ;; Create a /etc/hosts file with aliases for "localhost"
9829 ;; and "mymachine", as well as for Facebook servers.
9831 (string-append (local-host-aliases host-name)
9832 %facebook-host-aliases))))
9835 This mechanism can prevent programs running locally, such as Web
9836 browsers, from accessing Facebook.
9839 The @code{(gnu services avahi)} provides the following definition.
9841 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
9842 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
9843 [#:ipv6? #t] [#:wide-area? #f] @
9844 [#:domains-to-browse '()] [#:debug? #f]
9845 Return a service that runs @command{avahi-daemon}, a system-wide
9846 mDNS/DNS-SD responder that allows for service discovery and
9847 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
9848 extends the name service cache daemon (nscd) so that it can resolve
9849 @code{.local} host names using
9850 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
9851 add the @var{avahi} package to the system profile so that commands such as
9852 @command{avahi-browse} are directly usable.
9854 If @var{host-name} is different from @code{#f}, use that as the host name to
9855 publish for this machine; otherwise, use the machine's actual host name.
9857 When @var{publish?} is true, publishing of host names and services is allowed;
9858 in particular, avahi-daemon will publish the machine's host name and IP
9859 address via mDNS on the local network.
9861 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
9863 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
9867 @deffn {Scheme Variable} openvswitch-service-type
9868 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
9869 service, whose value should be an @code{openvswitch-configuration}
9873 @deftp {Data Type} openvswitch-configuration
9874 Data type representing the configuration of Open vSwitch, a multilayer
9875 virtual switch which is designed to enable massive network automation
9876 through programmatic extension.
9879 @item @code{package} (default: @var{openvswitch})
9880 Package object of the Open vSwitch.
9886 @subsubsection X Window
9889 @cindex X Window System
9890 Support for the X Window graphical display system---specifically
9891 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
9892 there is no @code{xorg-service} procedure. Instead, the X server is
9893 started by the @dfn{login manager}, currently SLiM.
9895 @deftp {Data Type} sddm-configuration
9896 This is the data type representing the sddm service configuration.
9899 @item @code{display-server} (default: "x11")
9900 Select display server to use for the greeter. Valid values are "x11"
9903 @item @code{numlock} (default: "on")
9904 Valid values are "on", "off" or "none".
9906 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
9907 Command to run when halting.
9909 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
9910 Command to run when rebooting.
9912 @item @code{theme} (default "maldives")
9913 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
9915 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
9916 Directory to look for themes.
9918 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
9919 Directory to look for faces.
9921 @item @code{default-path} (default "/run/current-system/profile/bin")
9922 Default PATH to use.
9924 @item @code{minimum-uid} (default 1000)
9925 Minimum UID to display in SDDM.
9927 @item @code{maximum-uid} (default 2000)
9928 Maximum UID to display in SDDM
9930 @item @code{remember-last-user?} (default #t)
9933 @item @code{remember-last-session?} (default #t)
9934 Remember last session.
9936 @item @code{hide-users} (default "")
9937 Usernames to hide from SDDM greeter.
9939 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
9940 Users with shells listed will be hidden from the SDDM greeter.
9942 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
9943 Script to run before starting a wayland session.
9945 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
9946 Directory to look for desktop files starting wayland sessions.
9948 @item @code{xorg-server-path} (default @code{xorg-start-command})
9949 Path to xorg-server.
9951 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
9954 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
9957 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
9958 Script to run after starting xorg-server.
9960 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
9961 Script to run before stopping xorg-server.
9963 @item @code{xsession-command} (default: @code{xinitr })
9964 Script to run before starting a X session.
9966 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
9967 Directory to look for desktop files starting X sessions.
9969 @item @code{minimum-vt} (default: 7)
9972 @item @code{xserver-arguments} (default "-nolisten tcp")
9973 Arguments to pass to xorg-server.
9975 @item @code{auto-login-user} (default "")
9976 User to use for auto-login.
9978 @item @code{auto-login-session} (default "")
9979 Desktop file to use for auto-login.
9981 @item @code{relogin?} (default #f)
9982 Relogin after logout.
9987 @cindex login manager
9988 @deffn {Scheme Procedure} sddm-service config
9989 Return a service that spawns the SDDM graphical login manager for config of
9990 type @code{<sddm-configuration>}.
9993 (sddm-service (sddm-configuration
9994 (auto-login-user "Alice")
9995 (auto-login-session "xfce.desktop")))
9999 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10000 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10001 [#:theme @var{%default-slim-theme}] @
10002 [#:theme-name @var{%default-slim-theme-name}]
10003 Return a service that spawns the SLiM graphical login manager, which in
10004 turn starts the X display server with @var{startx}, a command as returned by
10005 @code{xorg-start-command}.
10009 SLiM automatically looks for session types described by the @file{.desktop}
10010 files in @file{/run/current-system/profile/share/xsessions} and allows users
10011 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10012 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10013 adding them to the system-wide set of packages automatically makes them
10014 available at the log-in screen.
10016 In addition, @file{~/.xsession} files are honored. When available,
10017 @file{~/.xsession} must be an executable that starts a window manager
10018 and/or other X clients.
10020 When @var{allow-empty-passwords?} is true, allow logins with an empty
10021 password. When @var{auto-login?} is true, log in automatically as
10022 @var{default-user}.
10024 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10025 @var{theme} must be a gexp denoting the name of a directory containing the
10026 theme to use. In that case, @var{theme-name} specifies the name of the
10030 @defvr {Scheme Variable} %default-theme
10031 @defvrx {Scheme Variable} %default-theme-name
10032 The G-Expression denoting the default SLiM theme and its name.
10035 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10036 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10037 Return a derivation that builds a @var{guile} script to start the X server
10038 from @var{xorg-server}. @var{configuration-file} is the server configuration
10039 file or a derivation that builds it; when omitted, the result of
10040 @code{xorg-configuration-file} is used.
10042 Usually the X server is started by a login manager.
10045 @deffn {Scheme Procedure} xorg-configuration-file @
10046 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10047 Return a configuration file for the Xorg server containing search paths for
10048 all the common drivers.
10050 @var{drivers} must be either the empty list, in which case Xorg chooses a
10051 graphics driver automatically, or a list of driver names that will be tried in
10052 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10054 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10055 appropriate screen resolution; otherwise, it must be a list of
10056 resolutions---e.g., @code{((1024 768) (640 480))}.
10058 Last, @var{extra-config} is a list of strings or objects appended to the
10059 @code{text-file*} argument list. It is used to pass extra text to be added
10060 verbatim to the configuration file.
10063 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10064 Add @var{package}, a package for a screen-locker or screen-saver whose
10065 command is @var{program}, to the set of setuid programs and add a PAM entry
10066 for it. For example:
10069 (screen-locker-service xlockmore "xlock")
10072 makes the good ol' XlockMore usable.
10076 @node Printing Services
10077 @subsubsection Printing Services
10079 @cindex printer support with CUPS
10080 The @code{(gnu services cups)} module provides a Guix service definition
10081 for the CUPS printing service. To add printer support to a GuixSD
10082 system, add a @code{cups-service} to the operating system definition:
10084 @deffn {Scheme Variable} cups-service-type
10085 The service type for the CUPS print server. Its value should be a valid
10086 CUPS configuration (see below). To use the default settings, simply
10089 (service cups-service-type)
10093 The CUPS configuration controls the basic things about your CUPS
10094 installation: what interfaces it listens on, what to do if a print job
10095 fails, how much logging to do, and so on. To actually add a printer,
10096 you have to visit the @url{http://localhost:631} URL, or use a tool such
10097 as GNOME's printer configuration services. By default, configuring a
10098 CUPS service will generate a self-signed certificate if needed, for
10099 secure connections to the print server.
10101 Suppose you want to enable the Web interface of CUPS and also add
10102 support for HP printers @i{via} the @code{hplip} package. You can do
10103 that directly, like this (you need to use the @code{(gnu packages cups)}
10107 (service cups-service-type
10108 (cups-configuration
10109 (web-interface? #t)
10111 (list cups-filters hplip))))
10114 The available configuration parameters follow. Each parameter
10115 definition is preceded by its type; for example, @samp{string-list foo}
10116 indicates that the @code{foo} parameter should be specified as a list of
10117 strings. There is also a way to specify the configuration as a string,
10118 if you have an old @code{cupsd.conf} file that you want to port over
10119 from some other system; see the end for more details.
10121 @c The following documentation was initially generated by
10122 @c (generate-documentation) in (gnu services cups). Manually maintained
10123 @c documentation is better, so we shouldn't hesitate to edit below as
10124 @c needed. However if the change you want to make to this documentation
10125 @c can be done in an automated way, it's probably easier to change
10126 @c (generate-documentation) than to make it below and have to deal with
10127 @c the churn as CUPS updates.
10130 Available @code{cups-configuration} fields are:
10132 @deftypevr {@code{cups-configuration} parameter} package cups
10136 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10137 Drivers and other extensions to the CUPS package.
10140 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10141 Configuration of where to write logs, what directories to use for print
10142 spools, and related privileged configuration parameters.
10144 Available @code{files-configuration} fields are:
10146 @deftypevr {@code{files-configuration} parameter} log-location access-log
10147 Defines the access log filename. Specifying a blank filename disables
10148 access log generation. The value @code{stderr} causes log entries to be
10149 sent to the standard error file when the scheduler is running in the
10150 foreground, or to the system log daemon when run in the background. The
10151 value @code{syslog} causes log entries to be sent to the system log
10152 daemon. The server name may be included in filenames using the string
10153 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10155 Defaults to @samp{"/var/log/cups/access_log"}.
10158 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10159 Where CUPS should cache data.
10161 Defaults to @samp{"/var/cache/cups"}.
10164 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10165 Specifies the permissions for all configuration files that the scheduler
10168 Note that the permissions for the printers.conf file are currently
10169 masked to only allow access from the scheduler user (typically root).
10170 This is done because printer device URIs sometimes contain sensitive
10171 authentication information that should not be generally known on the
10172 system. There is no way to disable this security feature.
10174 Defaults to @samp{"0640"}.
10177 @deftypevr {@code{files-configuration} parameter} log-location error-log
10178 Defines the error log filename. Specifying a blank filename disables
10179 access log generation. The value @code{stderr} causes log entries to be
10180 sent to the standard error file when the scheduler is running in the
10181 foreground, or to the system log daemon when run in the background. The
10182 value @code{syslog} causes log entries to be sent to the system log
10183 daemon. The server name may be included in filenames using the string
10184 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10186 Defaults to @samp{"/var/log/cups/error_log"}.
10189 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10190 Specifies which errors are fatal, causing the scheduler to exit. The
10195 No errors are fatal.
10198 All of the errors below are fatal.
10201 Browsing initialization errors are fatal, for example failed connections
10202 to the DNS-SD daemon.
10205 Configuration file syntax errors are fatal.
10208 Listen or Port errors are fatal, except for IPv6 failures on the
10209 loopback or @code{any} addresses.
10212 Log file creation or write errors are fatal.
10215 Bad startup file permissions are fatal, for example shared TLS
10216 certificate and key files with world-read permissions.
10219 Defaults to @samp{"all -browse"}.
10222 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10223 Specifies whether the file pseudo-device can be used for new printer
10224 queues. The URI @uref{file:///dev/null} is always allowed.
10226 Defaults to @samp{#f}.
10229 @deftypevr {@code{files-configuration} parameter} string group
10230 Specifies the group name or ID that will be used when executing external
10233 Defaults to @samp{"lp"}.
10236 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10237 Specifies the permissions for all log files that the scheduler writes.
10239 Defaults to @samp{"0644"}.
10242 @deftypevr {@code{files-configuration} parameter} log-location page-log
10243 Defines the page log filename. Specifying a blank filename disables
10244 access log generation. The value @code{stderr} causes log entries to be
10245 sent to the standard error file when the scheduler is running in the
10246 foreground, or to the system log daemon when run in the background. The
10247 value @code{syslog} causes log entries to be sent to the system log
10248 daemon. The server name may be included in filenames using the string
10249 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10251 Defaults to @samp{"/var/log/cups/page_log"}.
10254 @deftypevr {@code{files-configuration} parameter} string remote-root
10255 Specifies the username that is associated with unauthenticated accesses
10256 by clients claiming to be the root user. The default is @code{remroot}.
10258 Defaults to @samp{"remroot"}.
10261 @deftypevr {@code{files-configuration} parameter} file-name request-root
10262 Specifies the directory that contains print jobs and other HTTP request
10265 Defaults to @samp{"/var/spool/cups"}.
10268 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10269 Specifies the level of security sandboxing that is applied to print
10270 filters, backends, and other child processes of the scheduler; either
10271 @code{relaxed} or @code{strict}. This directive is currently only
10272 used/supported on macOS.
10274 Defaults to @samp{strict}.
10277 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10278 Specifies the location of TLS certificates and private keys. CUPS will
10279 look for public and private keys in this directory: a @code{.crt} files
10280 for PEM-encoded certificates and corresponding @code{.key} files for
10281 PEM-encoded private keys.
10283 Defaults to @samp{"/etc/cups/ssl"}.
10286 @deftypevr {@code{files-configuration} parameter} file-name server-root
10287 Specifies the directory containing the server configuration files.
10289 Defaults to @samp{"/etc/cups"}.
10292 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10293 Specifies whether the scheduler calls fsync(2) after writing
10294 configuration or state files.
10296 Defaults to @samp{#f}.
10299 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10300 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10303 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10304 Specifies the directory where temporary files are stored.
10306 Defaults to @samp{"/var/spool/cups/tmp"}.
10309 @deftypevr {@code{files-configuration} parameter} string user
10310 Specifies the user name or ID that is used when running external
10313 Defaults to @samp{"lp"}.
10317 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10318 Specifies the logging level for the AccessLog file. The @code{config}
10319 level logs when printers and classes are added, deleted, or modified and
10320 when configuration files are accessed or updated. The @code{actions}
10321 level logs when print jobs are submitted, held, released, modified, or
10322 canceled, and any of the conditions for @code{config}. The @code{all}
10323 level logs all requests.
10325 Defaults to @samp{actions}.
10328 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10329 Specifies whether to purge job history data automatically when it is no
10330 longer required for quotas.
10332 Defaults to @samp{#f}.
10335 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10336 Specifies which protocols to use for local printer sharing.
10338 Defaults to @samp{dnssd}.
10341 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10342 Specifies whether the CUPS web interface is advertised.
10344 Defaults to @samp{#f}.
10347 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10348 Specifies whether shared printers are advertised.
10350 Defaults to @samp{#f}.
10353 @deftypevr {@code{cups-configuration} parameter} string classification
10354 Specifies the security classification of the server. Any valid banner
10355 name can be used, including "classified", "confidential", "secret",
10356 "topsecret", and "unclassified", or the banner can be omitted to disable
10357 secure printing functions.
10359 Defaults to @samp{""}.
10362 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
10363 Specifies whether users may override the classification (cover page) of
10364 individual print jobs using the @code{job-sheets} option.
10366 Defaults to @samp{#f}.
10369 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
10370 Specifies the default type of authentication to use.
10372 Defaults to @samp{Basic}.
10375 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
10376 Specifies whether encryption will be used for authenticated requests.
10378 Defaults to @samp{Required}.
10381 @deftypevr {@code{cups-configuration} parameter} string default-language
10382 Specifies the default language to use for text and web content.
10384 Defaults to @samp{"en"}.
10387 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
10388 Specifies the default paper size for new print queues. @samp{"Auto"}
10389 uses a locale-specific default, while @samp{"None"} specifies there is
10390 no default paper size. Specific size names are typically
10391 @samp{"Letter"} or @samp{"A4"}.
10393 Defaults to @samp{"Auto"}.
10396 @deftypevr {@code{cups-configuration} parameter} string default-policy
10397 Specifies the default access policy to use.
10399 Defaults to @samp{"default"}.
10402 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
10403 Specifies whether local printers are shared by default.
10405 Defaults to @samp{#t}.
10408 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
10409 Specifies the delay for updating of configuration and state files, in
10410 seconds. A value of 0 causes the update to happen as soon as possible,
10411 typically within a few milliseconds.
10413 Defaults to @samp{30}.
10416 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
10417 Specifies what to do when an error occurs. Possible values are
10418 @code{abort-job}, which will discard the failed print job;
10419 @code{retry-job}, which will retry the job at a later time;
10420 @code{retry-this-job}, which retries the failed job immediately; and
10421 @code{stop-printer}, which stops the printer.
10423 Defaults to @samp{stop-printer}.
10426 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
10427 Specifies the maximum cost of filters that are run concurrently, which
10428 can be used to minimize disk, memory, and CPU resource problems. A
10429 limit of 0 disables filter limiting. An average print to a
10430 non-PostScript printer needs a filter limit of about 200. A PostScript
10431 printer needs about half that (100). Setting the limit below these
10432 thresholds will effectively limit the scheduler to printing a single job
10435 Defaults to @samp{0}.
10438 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
10439 Specifies the scheduling priority of filters that are run to print a
10440 job. The nice value ranges from 0, the highest priority, to 19, the
10443 Defaults to @samp{0}.
10446 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
10447 Specifies whether to do reverse lookups on connecting clients. The
10448 @code{double} setting causes @code{cupsd} to verify that the hostname
10449 resolved from the address matches one of the addresses returned for that
10450 hostname. Double lookups also prevent clients with unregistered
10451 addresses from connecting to your server. Only set this option to
10452 @code{#t} or @code{double} if absolutely required.
10454 Defaults to @samp{#f}.
10457 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
10458 Specifies the number of seconds to wait before killing the filters and
10459 backend associated with a canceled or held job.
10461 Defaults to @samp{30}.
10464 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
10465 Specifies the interval between retries of jobs in seconds. This is
10466 typically used for fax queues but can also be used with normal print
10467 queues whose error policy is @code{retry-job} or
10468 @code{retry-current-job}.
10470 Defaults to @samp{30}.
10473 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
10474 Specifies the number of retries that are done for jobs. This is
10475 typically used for fax queues but can also be used with normal print
10476 queues whose error policy is @code{retry-job} or
10477 @code{retry-current-job}.
10479 Defaults to @samp{5}.
10482 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
10483 Specifies whether to support HTTP keep-alive connections.
10485 Defaults to @samp{#t}.
10488 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
10489 Specifies how long an idle client connection remains open, in seconds.
10491 Defaults to @samp{30}.
10494 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
10495 Specifies the maximum size of print files, IPP requests, and HTML form
10496 data. A limit of 0 disables the limit check.
10498 Defaults to @samp{0}.
10501 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
10502 Listens on the specified interfaces for connections. Valid values are
10503 of the form @var{address}:@var{port}, where @var{address} is either an
10504 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
10505 indicate all addresses. Values can also be file names of local UNIX
10506 domain sockets. The Listen directive is similar to the Port directive
10507 but allows you to restrict access to specific interfaces or networks.
10510 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
10511 Specifies the number of pending connections that will be allowed. This
10512 normally only affects very busy servers that have reached the MaxClients
10513 limit, but can also be triggered by large numbers of simultaneous
10514 connections. When the limit is reached, the operating system will
10515 refuse additional connections until the scheduler can accept the pending
10518 Defaults to @samp{128}.
10521 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
10522 Specifies a set of additional access controls.
10524 Available @code{location-access-controls} fields are:
10526 @deftypevr {@code{location-access-controls} parameter} file-name path
10527 Specifies the URI path to which the access control applies.
10530 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
10531 Access controls for all access to this path, in the same format as the
10532 @code{access-controls} of @code{operation-access-control}.
10534 Defaults to @samp{()}.
10537 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
10538 Access controls for method-specific access to this path.
10540 Defaults to @samp{()}.
10542 Available @code{method-access-controls} fields are:
10544 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
10545 If @code{#t}, apply access controls to all methods except the listed
10546 methods. Otherwise apply to only the listed methods.
10548 Defaults to @samp{#f}.
10551 @deftypevr {@code{method-access-controls} parameter} method-list methods
10552 Methods to which this access control applies.
10554 Defaults to @samp{()}.
10557 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
10558 Access control directives, as a list of strings. Each string should be
10559 one directive, such as "Order allow,deny".
10561 Defaults to @samp{()}.
10566 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
10567 Specifies the number of debugging messages that are retained for logging
10568 if an error occurs in a print job. Debug messages are logged regardless
10569 of the LogLevel setting.
10571 Defaults to @samp{100}.
10574 @deftypevr {@code{cups-configuration} parameter} log-level log-level
10575 Specifies the level of logging for the ErrorLog file. The value
10576 @code{none} stops all logging while @code{debug2} logs everything.
10578 Defaults to @samp{info}.
10581 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
10582 Specifies the format of the date and time in the log files. The value
10583 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
10585 Defaults to @samp{standard}.
10588 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
10589 Specifies the maximum number of simultaneous clients that are allowed by
10592 Defaults to @samp{100}.
10595 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
10596 Specifies the maximum number of simultaneous clients that are allowed
10597 from a single address.
10599 Defaults to @samp{100}.
10602 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
10603 Specifies the maximum number of copies that a user can print of each
10606 Defaults to @samp{9999}.
10609 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
10610 Specifies the maximum time a job may remain in the @code{indefinite}
10611 hold state before it is canceled. A value of 0 disables cancellation of
10614 Defaults to @samp{0}.
10617 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
10618 Specifies the maximum number of simultaneous jobs that are allowed. Set
10619 to 0 to allow an unlimited number of jobs.
10621 Defaults to @samp{500}.
10624 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
10625 Specifies the maximum number of simultaneous jobs that are allowed per
10626 printer. A value of 0 allows up to MaxJobs jobs per printer.
10628 Defaults to @samp{0}.
10631 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
10632 Specifies the maximum number of simultaneous jobs that are allowed per
10633 user. A value of 0 allows up to MaxJobs jobs per user.
10635 Defaults to @samp{0}.
10638 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
10639 Specifies the maximum time a job may take to print before it is
10640 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
10642 Defaults to @samp{10800}.
10645 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
10646 Specifies the maximum size of the log files before they are rotated, in
10647 bytes. The value 0 disables log rotation.
10649 Defaults to @samp{1048576}.
10652 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
10653 Specifies the maximum amount of time to allow between files in a
10654 multiple file print job, in seconds.
10656 Defaults to @samp{300}.
10659 @deftypevr {@code{cups-configuration} parameter} string page-log-format
10660 Specifies the format of PageLog lines. Sequences beginning with percent
10661 (@samp{%}) characters are replaced with the corresponding information,
10662 while all other characters are copied literally. The following percent
10663 sequences are recognized:
10667 insert a single percent character
10670 insert the value of the specified IPP attribute
10673 insert the number of copies for the current page
10676 insert the current page number
10679 insert the current date and time in common log format
10685 insert the printer name
10688 insert the username
10691 A value of the empty string disables page logging. The string @code{%p
10692 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
10693 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
10696 Defaults to @samp{""}.
10699 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
10700 Passes the specified environment variable(s) to child processes; a list
10703 Defaults to @samp{()}.
10706 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
10707 Specifies named access control policies.
10709 Available @code{policy-configuration} fields are:
10711 @deftypevr {@code{policy-configuration} parameter} string name
10712 Name of the policy.
10715 @deftypevr {@code{policy-configuration} parameter} string job-private-access
10716 Specifies an access list for a job's private values. @code{@@ACL} maps
10717 to the printer's requesting-user-name-allowed or
10718 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10719 owner. @code{@@SYSTEM} maps to the groups listed for the
10720 @code{system-group} field of the @code{files-config} configuration,
10721 which is reified into the @code{cups-files.conf(5)} file. Other
10722 possible elements of the access list include specific user names, and
10723 @code{@@@var{group}} to indicate members of a specific group. The
10724 access list may also be simply @code{all} or @code{default}.
10726 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10729 @deftypevr {@code{policy-configuration} parameter} string job-private-values
10730 Specifies the list of job values to make private, or @code{all},
10731 @code{default}, or @code{none}.
10733 Defaults to @samp{"job-name job-originating-host-name
10734 job-originating-user-name phone"}.
10737 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
10738 Specifies an access list for a subscription's private values.
10739 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
10740 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10741 owner. @code{@@SYSTEM} maps to the groups listed for the
10742 @code{system-group} field of the @code{files-config} configuration,
10743 which is reified into the @code{cups-files.conf(5)} file. Other
10744 possible elements of the access list include specific user names, and
10745 @code{@@@var{group}} to indicate members of a specific group. The
10746 access list may also be simply @code{all} or @code{default}.
10748 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10751 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
10752 Specifies the list of job values to make private, or @code{all},
10753 @code{default}, or @code{none}.
10755 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
10756 notify-subscriber-user-name notify-user-data"}.
10759 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
10760 Access control by IPP operation.
10762 Defaults to @samp{()}.
10766 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
10767 Specifies whether job files (documents) are preserved after a job is
10768 printed. If a numeric value is specified, job files are preserved for
10769 the indicated number of seconds after printing. Otherwise a boolean
10770 value applies indefinitely.
10772 Defaults to @samp{86400}.
10775 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
10776 Specifies whether the job history is preserved after a job is printed.
10777 If a numeric value is specified, the job history is preserved for the
10778 indicated number of seconds after printing. If @code{#t}, the job
10779 history is preserved until the MaxJobs limit is reached.
10781 Defaults to @samp{#t}.
10784 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
10785 Specifies the amount of time to wait for job completion before
10786 restarting the scheduler.
10788 Defaults to @samp{30}.
10791 @deftypevr {@code{cups-configuration} parameter} string rip-cache
10792 Specifies the maximum amount of memory to use when converting documents
10793 into bitmaps for a printer.
10795 Defaults to @samp{"128m"}.
10798 @deftypevr {@code{cups-configuration} parameter} string server-admin
10799 Specifies the email address of the server administrator.
10801 Defaults to @samp{"root@@localhost.localdomain"}.
10804 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
10805 The ServerAlias directive is used for HTTP Host header validation when
10806 clients connect to the scheduler from external interfaces. Using the
10807 special name @code{*} can expose your system to known browser-based DNS
10808 rebinding attacks, even when accessing sites through a firewall. If the
10809 auto-discovery of alternate names does not work, we recommend listing
10810 each alternate name with a ServerAlias directive instead of using
10813 Defaults to @samp{*}.
10816 @deftypevr {@code{cups-configuration} parameter} string server-name
10817 Specifies the fully-qualified host name of the server.
10819 Defaults to @samp{"localhost"}.
10822 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
10823 Specifies what information is included in the Server header of HTTP
10824 responses. @code{None} disables the Server header. @code{ProductOnly}
10825 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
10826 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
10827 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
10828 the output of the @code{uname} command. @code{Full} reports @code{CUPS
10829 2.0.0 (@var{uname}) IPP/2.0}.
10831 Defaults to @samp{Minimal}.
10834 @deftypevr {@code{cups-configuration} parameter} string set-env
10835 Set the specified environment variable to be passed to child processes.
10837 Defaults to @samp{"variable value"}.
10840 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
10841 Listens on the specified interfaces for encrypted connections. Valid
10842 values are of the form @var{address}:@var{port}, where @var{address} is
10843 either an IPv6 address enclosed in brackets, an IPv4 address, or
10844 @code{*} to indicate all addresses.
10846 Defaults to @samp{()}.
10849 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
10850 Sets encryption options. By default, CUPS only supports encryption
10851 using TLS v1.0 or higher using known secure cipher suites. The
10852 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
10853 required for some older clients that do not implement newer ones. The
10854 @code{AllowSSL3} option enables SSL v3.0, which is required for some
10855 older clients that do not support TLS v1.0.
10857 Defaults to @samp{()}.
10860 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
10861 Specifies whether the scheduler requires clients to strictly adhere to
10862 the IPP specifications.
10864 Defaults to @samp{#f}.
10867 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
10868 Specifies the HTTP request timeout, in seconds.
10870 Defaults to @samp{300}.
10874 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
10875 Specifies whether the web interface is enabled.
10877 Defaults to @samp{#f}.
10880 At this point you're probably thinking ``oh dear, Guix manual, I like
10881 you but you can stop already with the configuration options''. Indeed.
10882 However, one more point: it could be that you have an existing
10883 @code{cupsd.conf} that you want to use. In that case, you can pass an
10884 @code{opaque-cups-configuration} as the configuration of a
10885 @code{cups-service-type}.
10887 Available @code{opaque-cups-configuration} fields are:
10889 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
10893 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
10894 The contents of the @code{cupsd.conf}, as a string.
10897 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
10898 The contents of the @code{cups-files.conf} file, as a string.
10901 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
10902 strings of the same name, you could instantiate a CUPS service like
10906 (service cups-service-type
10907 (opaque-cups-configuration
10908 (cupsd.conf cupsd.conf)
10909 (cups-files.conf cups-files.conf)))
10913 @node Desktop Services
10914 @subsubsection Desktop Services
10916 The @code{(gnu services desktop)} module provides services that are
10917 usually useful in the context of a ``desktop'' setup---that is, on a
10918 machine running a graphical display server, possibly with graphical user
10919 interfaces, etc. It also defines services that provide specific desktop
10920 environments like GNOME and XFCE.
10922 To simplify things, the module defines a variable containing the set of
10923 services that users typically expect on a machine with a graphical
10924 environment and networking:
10926 @defvr {Scheme Variable} %desktop-services
10927 This is a list of services that builds upon @var{%base-services} and
10928 adds or adjusts services for a typical ``desktop'' setup.
10930 In particular, it adds a graphical login manager (@pxref{X Window,
10931 @code{slim-service}}), screen lockers,
10932 a network management tool (@pxref{Networking
10933 Services, @code{wicd-service}}), energy and color management services,
10934 the @code{elogind} login and seat manager, the Polkit privilege service,
10935 the GeoClue location service, an NTP client (@pxref{Networking
10936 Services}), the Avahi daemon, and has the name service switch service
10937 configured to be able to use @code{nss-mdns} (@pxref{Name Service
10941 The @var{%desktop-services} variable can be used as the @code{services}
10942 field of an @code{operating-system} declaration (@pxref{operating-system
10943 Reference, @code{services}}).
10945 Additionally, the @code{gnome-desktop-service} and
10946 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
10947 system. To ``add GNOME'' means that system-level services like the
10948 backlight adjustment helpers and the power management utilities are
10949 added to the system, extending @code{polkit} and @code{dbus}
10950 appropriately, allowing GNOME to operate with elevated privileges on a
10951 limited number of special-purpose system interfaces. Additionally,
10952 adding a service made by @code{gnome-desktop-service} adds the GNOME
10953 metapackage to the system profile. Likewise, adding the XFCE service
10954 not only adds the @code{xfce} metapackage to the system profile, but it
10955 also gives the Thunar file manager the ability to open a ``root-mode''
10956 file management window, if the user authenticates using the
10957 administrator's password via the standard polkit graphical interface.
10959 @deffn {Scheme Procedure} gnome-desktop-service
10960 Return a service that adds the @code{gnome} package to the system
10961 profile, and extends polkit with the actions from
10962 @code{gnome-settings-daemon}.
10965 @deffn {Scheme Procedure} xfce-desktop-service
10966 Return a service that adds the @code{xfce} package to the system profile,
10967 and extends polkit with the ability for @code{thunar} to manipulate the
10968 file system as root from within a user session, after the user has
10969 authenticated with the administrator's password.
10972 Because the GNOME and XFCE desktop services pull in so many packages,
10973 the default @code{%desktop-services} variable doesn't include either of
10974 them by default. To add GNOME or XFCE, just @code{cons} them onto
10975 @code{%desktop-services} in the @code{services} field of your
10976 @code{operating-system}:
10979 (use-modules (gnu))
10980 (use-service-modules desktop)
10983 ;; cons* adds items to the list given as its last argument.
10984 (services (cons* (gnome-desktop-service)
10985 (xfce-desktop-service)
10986 %desktop-services))
10990 These desktop environments will then be available as options in the
10991 graphical login window.
10993 The actual service definitions included in @code{%desktop-services} and
10994 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
10995 are described below.
10997 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
10998 Return a service that runs the ``system bus'', using @var{dbus}, with
10999 support for @var{services}.
11001 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11002 facility. Its system bus is used to allow system services to communicate
11003 and to be notified of system-wide events.
11005 @var{services} must be a list of packages that provide an
11006 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11007 and policy files. For example, to allow avahi-daemon to use the system bus,
11008 @var{services} must be equal to @code{(list avahi)}.
11011 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11012 Return a service that runs the @code{elogind} login and
11013 seat management daemon. @uref{https://github.com/andywingo/elogind,
11014 Elogind} exposes a D-Bus interface that can be used to know which users
11015 are logged in, know what kind of sessions they have open, suspend the
11016 system, inhibit system suspend, reboot the system, and other tasks.
11018 Elogind handles most system-level power events for a computer, for
11019 example suspending the system when a lid is closed, or shutting it down
11020 when the power button is pressed.
11022 The @var{config} keyword argument specifies the configuration for
11023 elogind, and should be the result of an @code{(elogind-configuration
11024 (@var{parameter} @var{value})...)} invocation. Available parameters and
11025 their default values are:
11028 @item kill-user-processes?
11030 @item kill-only-users
11032 @item kill-exclude-users
11034 @item inhibit-delay-max-seconds
11036 @item handle-power-key
11038 @item handle-suspend-key
11040 @item handle-hibernate-key
11042 @item handle-lid-switch
11044 @item handle-lid-switch-docked
11046 @item power-key-ignore-inhibited?
11048 @item suspend-key-ignore-inhibited?
11050 @item hibernate-key-ignore-inhibited?
11052 @item lid-switch-ignore-inhibited?
11054 @item holdoff-timeout-seconds
11058 @item idle-action-seconds
11060 @item runtime-directory-size-percent
11062 @item runtime-directory-size
11066 @item suspend-state
11067 @code{("mem" "standby" "freeze")}
11070 @item hibernate-state
11072 @item hibernate-mode
11073 @code{("platform" "shutdown")}
11074 @item hybrid-sleep-state
11076 @item hybrid-sleep-mode
11077 @code{("suspend" "platform" "shutdown")}
11081 @deffn {Scheme Procedure} polkit-service @
11082 [#:polkit @var{polkit}]
11083 Return a service that runs the
11084 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11085 management service}, which allows system administrators to grant access to
11086 privileged operations in a structured way. By querying the Polkit service, a
11087 privileged system component can know when it should grant additional
11088 capabilities to ordinary users. For example, an ordinary user can be granted
11089 the capability to suspend the system if the user is logged in locally.
11092 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11093 [#:watts-up-pro? #f] @
11094 [#:poll-batteries? #t] @
11095 [#:ignore-lid? #f] @
11096 [#:use-percentage-for-policy? #f] @
11097 [#:percentage-low 10] @
11098 [#:percentage-critical 3] @
11099 [#:percentage-action 2] @
11100 [#:time-low 1200] @
11101 [#:time-critical 300] @
11102 [#:time-action 120] @
11103 [#:critical-power-action 'hybrid-sleep]
11104 Return a service that runs @uref{http://upower.freedesktop.org/,
11105 @command{upowerd}}, a system-wide monitor for power consumption and battery
11106 levels, with the given configuration settings. It implements the
11107 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11111 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11112 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11113 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11114 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11115 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11118 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11119 Return a service that runs @command{colord}, a system service with a D-Bus
11120 interface to manage the color profiles of input and output devices such as
11121 screens and scanners. It is notably used by the GNOME Color Manager graphical
11122 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11123 site} for more information.
11126 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11127 Return a configuration allowing an application to access GeoClue
11128 location data. @var{name} is the Desktop ID of the application, without
11129 the @code{.desktop} part. If @var{allowed?} is true, the application
11130 will have access to location information by default. The boolean
11131 @var{system?} value indicates whether an application is a system component
11132 or not. Finally @var{users} is a list of UIDs of all users for which
11133 this application is allowed location info access. An empty users list
11134 means that all users are allowed.
11137 @defvr {Scheme Variable} %standard-geoclue-applications
11138 The standard list of well-known GeoClue application configurations,
11139 granting authority to the GNOME date-and-time utility to ask for the
11140 current location in order to set the time zone, and allowing the
11141 IceCat and Epiphany web browsers to request location information.
11142 IceCat and Epiphany both query the user before allowing a web page to
11143 know the user's location.
11146 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11147 [#:whitelist '()] @
11148 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11149 [#:submit-data? #f]
11150 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11151 [#:submission-nick "geoclue"] @
11152 [#:applications %standard-geoclue-applications]
11153 Return a service that runs the GeoClue location service. This service
11154 provides a D-Bus interface to allow applications to request access to a
11155 user's physical location, and optionally to add information to online
11156 location databases. See
11157 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11158 web site} for more information.
11161 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
11162 Return a service that runs the @command{bluetoothd} daemon, which manages
11163 all the Bluetooth devices and provides a number of D-Bus interfaces.
11165 Users need to be in the @code{lp} group to access the D-Bus service.
11168 @node Database Services
11169 @subsubsection Database Services
11173 The @code{(gnu services databases)} module provides the following services.
11175 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11176 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11177 [#:port 5432] [#:locale ``en_US.utf8'']
11178 Return a service that runs @var{postgresql}, the PostgreSQL database
11181 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11182 creates a database cluster with @var{locale} as the default
11183 locale, stored in @var{data-directory}. It then listens on @var{port}.
11186 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11187 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11190 The optional @var{config} argument specifies the configuration for
11191 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11194 @deftp {Data Type} mysql-configuration
11195 Data type representing the configuration of @var{mysql-service}.
11198 @item @code{mysql} (default: @var{mariadb})
11199 Package object of the MySQL database server, can be either @var{mariadb}
11202 For MySQL, a temporary root password will be displayed at activation time.
11203 For MariaDB, the root password is empty.
11205 @item @code{port} (default: @code{3306})
11206 TCP port on which the database server listens for incoming connections.
11210 @defvr {Scheme Variable} redis-service-type
11211 This is the service type for the @uref{https://redis.io/, Redis}
11212 key/value store, whose value is a @code{redis-configuration} object.
11215 @deftp {Data Type} redis-configuration
11216 Data type representing the configuration of redis.
11219 @item @code{redis} (default: @code{redis})
11220 The Redis package to use.
11222 @item @code{bind} (default: @code{"127.0.0.1"})
11223 Network interface on which to listen.
11225 @item @code{port} (default: @code{6379})
11226 Port on which to accept connections on, a value of 0 will disable
11227 listening on a TCP socket.
11229 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11230 Directory in which to store the database and related files.
11234 @node Mail Services
11235 @subsubsection Mail Services
11239 The @code{(gnu services mail)} module provides Guix service definitions
11240 for email services: IMAP, POP3, and LMTP servers, as well as mail
11241 transport agents (MTAs). Lots of acronyms! These services are detailed
11242 in the subsections below.
11244 @subsubheading Dovecot Service
11246 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11247 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11250 By default, Dovecot does not need much configuration; the default
11251 configuration object created by @code{(dovecot-configuration)} will
11252 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11253 certificate will be generated for TLS-protected connections, though
11254 Dovecot will also listen on cleartext ports by default. There are a
11255 number of options, though, which mail administrators might need to change,
11256 and as is the case with other services, Guix allows the system
11257 administrator to specify these parameters via a uniform Scheme interface.
11259 For example, to specify that mail is located at @code{maildir~/.mail},
11260 one would instantiate the Dovecot service like this:
11263 (dovecot-service #:config
11264 (dovecot-configuration
11265 (mail-location "maildir:~/.mail")))
11268 The available configuration parameters follow. Each parameter
11269 definition is preceded by its type; for example, @samp{string-list foo}
11270 indicates that the @code{foo} parameter should be specified as a list of
11271 strings. There is also a way to specify the configuration as a string,
11272 if you have an old @code{dovecot.conf} file that you want to port over
11273 from some other system; see the end for more details.
11275 @c The following documentation was initially generated by
11276 @c (generate-documentation) in (gnu services mail). Manually maintained
11277 @c documentation is better, so we shouldn't hesitate to edit below as
11278 @c needed. However if the change you want to make to this documentation
11279 @c can be done in an automated way, it's probably easier to change
11280 @c (generate-documentation) than to make it below and have to deal with
11281 @c the churn as dovecot updates.
11283 Available @code{dovecot-configuration} fields are:
11285 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11286 The dovecot package.
11289 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11290 A list of IPs or hosts where to listen for connections. @samp{*}
11291 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11292 interfaces. If you want to specify non-default ports or anything more
11293 complex, customize the address and port fields of the
11294 @samp{inet-listener} of the specific services you are interested in.
11297 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11298 List of protocols we want to serve. Available protocols include
11299 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11301 Available @code{protocol-configuration} fields are:
11303 @deftypevr {@code{protocol-configuration} parameter} string name
11304 The name of the protocol.
11307 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
11308 UNIX socket path to the master authentication server to find users.
11309 This is used by imap (for shared users) and lda.
11310 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11313 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
11314 Space separated list of plugins to load.
11317 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
11318 Maximum number of IMAP connections allowed for a user from each IP
11319 address. NOTE: The username is compared case-sensitively.
11320 Defaults to @samp{10}.
11325 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
11326 List of services to enable. Available services include @samp{imap},
11327 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
11330 Available @code{service-configuration} fields are:
11332 @deftypevr {@code{service-configuration} parameter} string kind
11333 The service kind. Valid values include @code{director},
11334 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
11335 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
11336 @code{tcpwrap}, @code{quota-warning}, or anything else.
11339 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
11340 Listeners for the service. A listener is either a
11341 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
11342 an @code{inet-listener-configuration}.
11343 Defaults to @samp{()}.
11345 Available @code{unix-listener-configuration} fields are:
11347 @deftypevr {@code{unix-listener-configuration} parameter} string path
11348 Path to the file, relative to @code{base-dir} field. This is also used as
11352 @deftypevr {@code{unix-listener-configuration} parameter} string mode
11353 The access mode for the socket.
11354 Defaults to @samp{"0600"}.
11357 @deftypevr {@code{unix-listener-configuration} parameter} string user
11358 The user to own the socket.
11359 Defaults to @samp{""}.
11362 @deftypevr {@code{unix-listener-configuration} parameter} string group
11363 The group to own the socket.
11364 Defaults to @samp{""}.
11368 Available @code{fifo-listener-configuration} fields are:
11370 @deftypevr {@code{fifo-listener-configuration} parameter} string path
11371 Path to the file, relative to @code{base-dir} field. This is also used as
11375 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
11376 The access mode for the socket.
11377 Defaults to @samp{"0600"}.
11380 @deftypevr {@code{fifo-listener-configuration} parameter} string user
11381 The user to own the socket.
11382 Defaults to @samp{""}.
11385 @deftypevr {@code{fifo-listener-configuration} parameter} string group
11386 The group to own the socket.
11387 Defaults to @samp{""}.
11391 Available @code{inet-listener-configuration} fields are:
11393 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
11394 The protocol to listen for.
11397 @deftypevr {@code{inet-listener-configuration} parameter} string address
11398 The address on which to listen, or empty for all addresses.
11399 Defaults to @samp{""}.
11402 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
11403 The port on which to listen.
11406 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
11407 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
11409 Defaults to @samp{#t}.
11414 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
11415 Number of connections to handle before starting a new process.
11416 Typically the only useful values are 0 (unlimited) or 1. 1 is more
11417 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
11418 Defaults to @samp{1}.
11421 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
11422 Number of processes to always keep waiting for more connections.
11423 Defaults to @samp{0}.
11426 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
11427 If you set @samp{service-count 0}, you probably need to grow
11429 Defaults to @samp{256000000}.
11434 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
11435 Dict configuration, as created by the @code{dict-configuration}
11438 Available @code{dict-configuration} fields are:
11440 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
11441 A list of key-value pairs that this dict should hold.
11442 Defaults to @samp{()}.
11447 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
11448 A list of passdb configurations, each one created by the
11449 @code{passdb-configuration} constructor.
11451 Available @code{passdb-configuration} fields are:
11453 @deftypevr {@code{passdb-configuration} parameter} string driver
11454 The driver that the passdb should use. Valid values include
11455 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
11457 Defaults to @samp{"pam"}.
11460 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
11461 Space separated list of arguments to the passdb driver.
11462 Defaults to @samp{""}.
11467 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
11468 List of userdb configurations, each one created by the
11469 @code{userdb-configuration} constructor.
11471 Available @code{userdb-configuration} fields are:
11473 @deftypevr {@code{userdb-configuration} parameter} string driver
11474 The driver that the userdb should use. Valid values include
11475 @samp{passwd} and @samp{static}.
11476 Defaults to @samp{"passwd"}.
11479 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
11480 Space separated list of arguments to the userdb driver.
11481 Defaults to @samp{""}.
11484 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
11485 Override fields from passwd.
11486 Defaults to @samp{()}.
11491 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
11492 Plug-in configuration, created by the @code{plugin-configuration}
11496 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
11497 List of namespaces. Each item in the list is created by the
11498 @code{namespace-configuration} constructor.
11500 Available @code{namespace-configuration} fields are:
11502 @deftypevr {@code{namespace-configuration} parameter} string name
11503 Name for this namespace.
11506 @deftypevr {@code{namespace-configuration} parameter} string type
11507 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
11508 Defaults to @samp{"private"}.
11511 @deftypevr {@code{namespace-configuration} parameter} string separator
11512 Hierarchy separator to use. You should use the same separator for
11513 all namespaces or some clients get confused. @samp{/} is usually a good
11514 one. The default however depends on the underlying mail storage
11516 Defaults to @samp{""}.
11519 @deftypevr {@code{namespace-configuration} parameter} string prefix
11520 Prefix required to access this namespace. This needs to be
11521 different for all namespaces. For example @samp{Public/}.
11522 Defaults to @samp{""}.
11525 @deftypevr {@code{namespace-configuration} parameter} string location
11526 Physical location of the mailbox. This is in the same format as
11527 mail_location, which is also the default for it.
11528 Defaults to @samp{""}.
11531 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
11532 There can be only one INBOX, and this setting defines which
11534 Defaults to @samp{#f}.
11537 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
11538 If namespace is hidden, it's not advertised to clients via NAMESPACE
11539 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
11540 useful when converting from another server with different namespaces
11541 which you want to deprecate but still keep working. For example you can
11542 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
11544 Defaults to @samp{#f}.
11547 @deftypevr {@code{namespace-configuration} parameter} boolean list?
11548 Show the mailboxes under this namespace with the LIST command. This
11549 makes the namespace visible for clients that do not support the NAMESPACE
11550 extension. The special @code{children} value lists child mailboxes, but
11551 hides the namespace prefix.
11552 Defaults to @samp{#t}.
11555 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
11556 Namespace handles its own subscriptions. If set to @code{#f}, the
11557 parent namespace handles them. The empty prefix should always have this
11559 Defaults to @samp{#t}.
11562 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
11563 List of predefined mailboxes in this namespace.
11564 Defaults to @samp{()}.
11566 Available @code{mailbox-configuration} fields are:
11568 @deftypevr {@code{mailbox-configuration} parameter} string name
11569 Name for this mailbox.
11572 @deftypevr {@code{mailbox-configuration} parameter} string auto
11573 @samp{create} will automatically create this mailbox.
11574 @samp{subscribe} will both create and subscribe to the mailbox.
11575 Defaults to @samp{"no"}.
11578 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
11579 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
11580 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
11581 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
11582 Defaults to @samp{()}.
11589 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
11590 Base directory where to store runtime data.
11591 Defaults to @samp{"/var/run/dovecot/"}.
11594 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
11595 Greeting message for clients.
11596 Defaults to @samp{"Dovecot ready."}.
11599 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
11600 List of trusted network ranges. Connections from these IPs are
11601 allowed to override their IP addresses and ports (for logging and for
11602 authentication checks). @samp{disable-plaintext-auth} is also ignored
11603 for these networks. Typically you would specify your IMAP proxy servers
11605 Defaults to @samp{()}.
11608 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
11609 List of login access check sockets (e.g. tcpwrap).
11610 Defaults to @samp{()}.
11613 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
11614 Show more verbose process titles (in ps). Currently shows user name
11615 and IP address. Useful for seeing who is actually using the IMAP
11616 processes (e.g. shared mailboxes or if the same uid is used for multiple
11618 Defaults to @samp{#f}.
11621 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
11622 Should all processes be killed when Dovecot master process shuts down.
11623 Setting this to @code{#f} means that Dovecot can be upgraded without
11624 forcing existing client connections to close (although that could also
11625 be a problem if the upgrade is e.g. due to a security fix).
11626 Defaults to @samp{#t}.
11629 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
11630 If non-zero, run mail commands via this many connections to doveadm
11631 server, instead of running them directly in the same process.
11632 Defaults to @samp{0}.
11635 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
11636 UNIX socket or host:port used for connecting to doveadm server.
11637 Defaults to @samp{"doveadm-server"}.
11640 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
11641 List of environment variables that are preserved on Dovecot startup
11642 and passed down to all of its child processes. You can also give
11643 key=value pairs to always set specific settings.
11646 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
11647 Disable LOGIN command and all other plaintext authentications unless
11648 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
11649 matches the local IP (i.e. you're connecting from the same computer),
11650 the connection is considered secure and plaintext authentication is
11651 allowed. See also ssl=required setting.
11652 Defaults to @samp{#t}.
11655 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
11656 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
11657 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
11658 for caching to be used.
11659 Defaults to @samp{0}.
11662 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
11663 Time to live for cached data. After TTL expires the cached record
11664 is no longer used, *except* if the main database lookup returns internal
11665 failure. We also try to handle password changes automatically: If
11666 user's previous authentication was successful, but this one wasn't, the
11667 cache isn't used. For now this works only with plaintext
11669 Defaults to @samp{"1 hour"}.
11672 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
11673 TTL for negative hits (user not found, password mismatch).
11674 0 disables caching them completely.
11675 Defaults to @samp{"1 hour"}.
11678 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
11679 List of realms for SASL authentication mechanisms that need them.
11680 You can leave it empty if you don't want to support multiple realms.
11681 Many clients simply use the first one listed here, so keep the default
11683 Defaults to @samp{()}.
11686 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
11687 Default realm/domain to use if none was specified. This is used for
11688 both SASL realms and appending @@domain to username in plaintext
11690 Defaults to @samp{""}.
11693 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
11694 List of allowed characters in username. If the user-given username
11695 contains a character not listed in here, the login automatically fails.
11696 This is just an extra check to make sure user can't exploit any
11697 potential quote escaping vulnerabilities with SQL/LDAP databases. If
11698 you want to allow all characters, set this value to empty.
11699 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
11702 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
11703 Username character translations before it's looked up from
11704 databases. The value contains series of from -> to characters. For
11705 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
11706 translated to @samp{@@}.
11707 Defaults to @samp{""}.
11710 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
11711 Username formatting before it's looked up from databases. You can
11712 use the standard variables here, e.g. %Lu would lowercase the username,
11713 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
11714 change the @samp{@@} into @samp{-AT-}. This translation is done after
11715 @samp{auth-username-translation} changes.
11716 Defaults to @samp{"%Lu"}.
11719 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
11720 If you want to allow master users to log in by specifying the master
11721 username within the normal username string (i.e. not using SASL
11722 mechanism's support for it), you can specify the separator character
11723 here. The format is then <username><separator><master username>.
11724 UW-IMAP uses @samp{*} as the separator, so that could be a good
11726 Defaults to @samp{""}.
11729 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
11730 Username to use for users logging in with ANONYMOUS SASL
11732 Defaults to @samp{"anonymous"}.
11735 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
11736 Maximum number of dovecot-auth worker processes. They're used to
11737 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
11738 They're automatically created and destroyed as needed.
11739 Defaults to @samp{30}.
11742 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
11743 Host name to use in GSSAPI principal names. The default is to use
11744 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
11745 allow all keytab entries.
11746 Defaults to @samp{""}.
11749 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
11750 Kerberos keytab to use for the GSSAPI mechanism. Will use the
11751 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
11752 need to change the auth service to run as root to be able to read this
11754 Defaults to @samp{""}.
11757 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
11758 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
11759 and @samp{ntlm-auth} helper.
11760 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
11761 Defaults to @samp{#f}.
11764 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
11765 Path for Samba's @samp{ntlm-auth} helper binary.
11766 Defaults to @samp{"/usr/bin/ntlm_auth"}.
11769 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
11770 Time to delay before replying to failed authentications.
11771 Defaults to @samp{"2 secs"}.
11774 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
11775 Require a valid SSL client certificate or the authentication
11777 Defaults to @samp{#f}.
11780 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
11781 Take the username from client's SSL certificate, using
11782 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
11784 Defaults to @samp{#f}.
11787 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
11788 List of wanted authentication mechanisms. Supported mechanisms are:
11789 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
11790 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
11791 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
11792 @samp{disable-plaintext-auth} setting.
11795 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
11796 List of IPs or hostnames to all director servers, including ourself.
11797 Ports can be specified as ip:port. The default port is the same as what
11798 director service's @samp{inet-listener} is using.
11799 Defaults to @samp{()}.
11802 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
11803 List of IPs or hostnames to all backend mail servers. Ranges are
11804 allowed too, like 10.0.0.10-10.0.0.30.
11805 Defaults to @samp{()}.
11808 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
11809 How long to redirect users to a specific server after it no longer
11810 has any connections.
11811 Defaults to @samp{"15 min"}.
11814 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
11815 TCP/IP port that accepts doveadm connections (instead of director
11816 connections) If you enable this, you'll also need to add
11817 @samp{inet-listener} for the port.
11818 Defaults to @samp{0}.
11821 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
11822 How the username is translated before being hashed. Useful values
11823 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
11824 are shared within domain.
11825 Defaults to @samp{"%Lu"}.
11828 @deftypevr {@code{dovecot-configuration} parameter} string log-path
11829 Log file to use for error messages. @samp{syslog} logs to syslog,
11830 @samp{/dev/stderr} logs to stderr.
11831 Defaults to @samp{"syslog"}.
11834 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
11835 Log file to use for informational messages. Defaults to
11837 Defaults to @samp{""}.
11840 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
11841 Log file to use for debug messages. Defaults to
11842 @samp{info-log-path}.
11843 Defaults to @samp{""}.
11846 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
11847 Syslog facility to use if you're logging to syslog. Usually if you
11848 don't want to use @samp{mail}, you'll use local0..local7. Also other
11849 standard facilities are supported.
11850 Defaults to @samp{"mail"}.
11853 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
11854 Log unsuccessful authentication attempts and the reasons why they
11856 Defaults to @samp{#f}.
11859 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
11860 In case of password mismatches, log the attempted password. Valid
11861 values are no, plain and sha1. sha1 can be useful for detecting brute
11862 force password attempts vs. user simply trying the same password over
11863 and over again. You can also truncate the value to n chars by appending
11864 ":n" (e.g. sha1:6).
11865 Defaults to @samp{#f}.
11868 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
11869 Even more verbose logging for debugging purposes. Shows for example
11871 Defaults to @samp{#f}.
11874 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
11875 In case of password mismatches, log the passwords and used scheme so
11876 the problem can be debugged. Enabling this also enables
11878 Defaults to @samp{#f}.
11881 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
11882 Enable mail process debugging. This can help you figure out why
11883 Dovecot isn't finding your mails.
11884 Defaults to @samp{#f}.
11887 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
11888 Show protocol level SSL errors.
11889 Defaults to @samp{#f}.
11892 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
11893 Prefix for each line written to log file. % codes are in
11894 strftime(3) format.
11895 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
11898 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
11899 List of elements we want to log. The elements which have a
11900 non-empty variable value are joined together to form a comma-separated
11904 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
11905 Login log format. %s contains @samp{login-log-format-elements}
11906 string, %$ contains the data we want to log.
11907 Defaults to @samp{"%$: %s"}.
11910 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
11911 Log prefix for mail processes. See doc/wiki/Variables.txt for list
11912 of possible variables you can use.
11913 Defaults to @samp{"\"%s(%u): \""}.
11916 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
11917 Format to use for logging mail deliveries. You can use variables:
11920 Delivery status message (e.g. @samp{saved to INBOX})
11932 Defaults to @samp{"msgid=%m: %$"}.
11935 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
11936 Location for users' mailboxes. The default is empty, which means
11937 that Dovecot tries to find the mailboxes automatically. This won't work
11938 if the user doesn't yet have any mail, so you should explicitly tell
11939 Dovecot the full location.
11941 If you're using mbox, giving a path to the INBOX
11942 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
11943 where the other mailboxes are kept. This is called the "root mail
11944 directory", and it must be the first path given in the
11945 @samp{mail-location} setting.
11947 There are a few special variables you can use, eg.:
11953 user part in user@@domain, same as %u if there's no domain
11955 domain part in user@@domain, empty if there's no domain
11960 See doc/wiki/Variables.txt for full list. Some examples:
11962 @item maildir:~/Maildir
11963 @item mbox:~/mail:INBOX=/var/mail/%u
11964 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
11966 Defaults to @samp{""}.
11969 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
11970 System user and group used to access mails. If you use multiple,
11971 userdb can override these by returning uid or gid fields. You can use
11972 either numbers or names. <doc/wiki/UserIds.txt>.
11973 Defaults to @samp{""}.
11976 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
11978 Defaults to @samp{""}.
11981 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
11982 Group to enable temporarily for privileged operations. Currently
11983 this is used only with INBOX when either its initial creation or
11984 dotlocking fails. Typically this is set to "mail" to give access to
11986 Defaults to @samp{""}.
11989 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
11990 Grant access to these supplementary groups for mail processes.
11991 Typically these are used to set up access to shared mailboxes. Note
11992 that it may be dangerous to set these if users can create
11993 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
11994 could allow a user to delete others' mailboxes, or ln -s
11995 /secret/shared/box ~/mail/mybox would allow reading it).
11996 Defaults to @samp{""}.
11999 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12000 Allow full file system access to clients. There's no access checks
12001 other than what the operating system does for the active UID/GID. It
12002 works with both maildir and mboxes, allowing you to prefix mailboxes
12003 names with e.g. /path/ or ~user/.
12004 Defaults to @samp{#f}.
12007 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12008 Don't use mmap() at all. This is required if you store indexes to
12009 shared file systems (NFS or clustered file system).
12010 Defaults to @samp{#f}.
12013 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12014 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12015 supports @samp{O_EXCL} since version 3, so this should be safe to use
12016 nowadays by default.
12017 Defaults to @samp{#t}.
12020 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12021 When to use fsync() or fdatasync() calls:
12024 Whenever necessary to avoid losing important data
12026 Useful with e.g. NFS when write()s are delayed
12028 Never use it (best performance, but crashes can lose data).
12030 Defaults to @samp{"optimized"}.
12033 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12034 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12035 NFS caches whenever needed. If you're using only a single mail server
12037 Defaults to @samp{#f}.
12040 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12041 Mail index files also exist in NFS. Setting this to yes requires
12042 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12043 Defaults to @samp{#f}.
12046 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12047 Locking method for index files. Alternatives are fcntl, flock and
12048 dotlock. Dotlocking uses some tricks which may create more disk I/O
12049 than other locking methods. NFS users: flock doesn't work, remember to
12050 change @samp{mmap-disable}.
12051 Defaults to @samp{"fcntl"}.
12054 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12055 Directory in which LDA/LMTP temporarily stores incoming mails >128
12057 Defaults to @samp{"/tmp"}.
12060 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12061 Valid UID range for users. This is mostly to make sure that users can't
12062 log in as daemons or other system users. Note that denying root logins is
12063 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12065 Defaults to @samp{500}.
12068 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12070 Defaults to @samp{0}.
12073 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12074 Valid GID range for users. Users having non-valid GID as primary group ID
12075 aren't allowed to log in. If user belongs to supplementary groups with
12076 non-valid GIDs, those groups are not set.
12077 Defaults to @samp{1}.
12080 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12082 Defaults to @samp{0}.
12085 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12086 Maximum allowed length for mail keyword name. It's only forced when
12087 trying to create new keywords.
12088 Defaults to @samp{50}.
12091 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12092 List of directories under which chrooting is allowed for mail
12093 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12094 too). This setting doesn't affect @samp{login-chroot}
12095 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12096 "/./" in home dirs are ignored. WARNING: Never add directories here
12097 which local users can modify, that may lead to root exploit. Usually
12098 this should be done only if you don't allow shell access for users.
12099 <doc/wiki/Chrooting.txt>.
12100 Defaults to @samp{()}.
12103 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12104 Default chroot directory for mail processes. This can be overridden
12105 for specific users in user database by giving /./ in user's home
12106 directory (e.g. /home/./user chroots into /home). Note that usually
12107 there is no real need to do chrooting, Dovecot doesn't allow users to
12108 access files outside their mail directory anyway. If your home
12109 directories are prefixed with the chroot directory, append "/." to
12110 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12111 Defaults to @samp{""}.
12114 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12115 UNIX socket path to master authentication server to find users.
12116 This is used by imap (for shared users) and lda.
12117 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12120 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12121 Directory where to look up mail plugins.
12122 Defaults to @samp{"/usr/lib/dovecot"}.
12125 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12126 List of plugins to load for all services. Plugins specific to IMAP,
12127 LDA, etc. are added to this list in their own .conf files.
12128 Defaults to @samp{()}.
12131 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12132 The minimum number of mails in a mailbox before updates are done to
12133 cache file. This allows optimizing Dovecot's behavior to do less disk
12134 writes at the cost of more disk reads.
12135 Defaults to @samp{0}.
12138 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12139 When IDLE command is running, mailbox is checked once in a while to
12140 see if there are any new mails or other changes. This setting defines
12141 the minimum time to wait between those checks. Dovecot can also use
12142 dnotify, inotify and kqueue to find out immediately when changes
12144 Defaults to @samp{"30 secs"}.
12147 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12148 Save mails with CR+LF instead of plain LF. This makes sending those
12149 mails take less CPU, especially with sendfile() syscall with Linux and
12150 FreeBSD. But it also creates a bit more disk I/O which may just make it
12151 slower. Also note that if other software reads the mboxes/maildirs,
12152 they may handle the extra CRs wrong and cause problems.
12153 Defaults to @samp{#f}.
12156 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12157 By default LIST command returns all entries in maildir beginning
12158 with a dot. Enabling this option makes Dovecot return only entries
12159 which are directories. This is done by stat()ing each entry, so it
12160 causes more disk I/O.
12161 (For systems setting struct @samp{dirent->d_type} this check is free
12162 and it's done always regardless of this setting).
12163 Defaults to @samp{#f}.
12166 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12167 When copying a message, do it with hard links whenever possible.
12168 This makes the performance much better, and it's unlikely to have any
12170 Defaults to @samp{#t}.
12173 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12174 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12175 directory only when its mtime changes unexpectedly or when we can't find
12176 the mail otherwise.
12177 Defaults to @samp{#f}.
12180 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12181 Which locking methods to use for locking mbox. There are four
12186 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12187 solution. If you want to use /var/mail/ like directory, the users will
12188 need write access to that directory.
12190 Same as dotlock, but if it fails because of permissions or because there
12191 isn't enough disk space, just skip it.
12193 Use this if possible. Works with NFS too if lockd is used.
12195 May not exist in all systems. Doesn't work with NFS.
12197 May not exist in all systems. Doesn't work with NFS.
12200 You can use multiple locking methods; if you do the order they're declared
12201 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12202 locking methods as well. Some operating systems don't allow using some of
12203 them simultaneously.
12206 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12210 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12211 Maximum time to wait for lock (all of them) before aborting.
12212 Defaults to @samp{"5 mins"}.
12215 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12216 If dotlock exists but the mailbox isn't modified in any way,
12217 override the lock file after this much time.
12218 Defaults to @samp{"2 mins"}.
12221 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12222 When mbox changes unexpectedly we have to fully read it to find out
12223 what changed. If the mbox is large this can take a long time. Since
12224 the change is usually just a newly appended mail, it'd be faster to
12225 simply read the new mails. If this setting is enabled, Dovecot does
12226 this but still safely fallbacks to re-reading the whole mbox file
12227 whenever something in mbox isn't how it's expected to be. The only real
12228 downside to this setting is that if some other MUA changes message
12229 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12230 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12231 Defaults to @samp{#t}.
12234 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12235 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12236 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12237 @samp{mbox-dirty-syncs} is ignored.
12238 Defaults to @samp{#f}.
12241 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12242 Delay writing mbox headers until doing a full write sync (EXPUNGE
12243 and CHECK commands and when closing the mailbox). This is especially
12244 useful for POP3 where clients often delete all mails. The downside is
12245 that our changes aren't immediately visible to other MUAs.
12246 Defaults to @samp{#t}.
12249 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12250 If mbox size is smaller than this (e.g. 100k), don't write index
12251 files. If an index file already exists it's still read, just not
12253 Defaults to @samp{0}.
12256 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12257 Maximum dbox file size until it's rotated.
12258 Defaults to @samp{2000000}.
12261 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12262 Maximum dbox file age until it's rotated. Typically in days. Day
12263 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12265 Defaults to @samp{"1d"}.
12268 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12269 When creating new mdbox files, immediately preallocate their size to
12270 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12271 with some file systems (ext4, xfs).
12272 Defaults to @samp{#f}.
12275 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12276 sdbox and mdbox support saving mail attachments to external files,
12277 which also allows single instance storage for them. Other backends
12278 don't support this for now.
12280 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12282 Directory root where to store mail attachments. Disabled, if empty.
12283 Defaults to @samp{""}.
12286 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12287 Attachments smaller than this aren't saved externally. It's also
12288 possible to write a plugin to disable saving specific attachments
12290 Defaults to @samp{128000}.
12293 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12294 File system backend to use for saving attachments:
12297 No SiS done by Dovecot (but this might help FS's own deduplication)
12299 SiS with immediate byte-by-byte comparison during saving
12300 @item sis-queue posix
12301 SiS with delayed comparison and deduplication.
12303 Defaults to @samp{"sis posix"}.
12306 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
12307 Hash format to use in attachment filenames. You can add any text and
12308 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
12309 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
12310 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
12311 Defaults to @samp{"%@{sha1@}"}.
12314 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
12316 Defaults to @samp{100}.
12319 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
12321 Defaults to @samp{1000}.
12324 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
12325 Default VSZ (virtual memory size) limit for service processes.
12326 This is mainly intended to catch and kill processes that leak memory
12327 before they eat up everything.
12328 Defaults to @samp{256000000}.
12331 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
12332 Login user is internally used by login processes. This is the most
12333 untrusted user in Dovecot system. It shouldn't have access to anything
12335 Defaults to @samp{"dovenull"}.
12338 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
12339 Internal user is used by unprivileged processes. It should be
12340 separate from login user, so that login processes can't disturb other
12342 Defaults to @samp{"dovecot"}.
12345 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
12346 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
12347 Defaults to @samp{"required"}.
12350 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
12351 PEM encoded X.509 SSL/TLS certificate (public key).
12352 Defaults to @samp{"</etc/dovecot/default.pem"}.
12355 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
12356 PEM encoded SSL/TLS private key. The key is opened before
12357 dropping root privileges, so keep the key file unreadable by anyone but
12359 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
12362 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
12363 If key file is password protected, give the password here.
12364 Alternatively give it when starting dovecot with -p parameter. Since
12365 this file is often world-readable, you may want to place this setting
12366 instead to a different.
12367 Defaults to @samp{""}.
12370 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
12371 PEM encoded trusted certificate authority. Set this only if you
12372 intend to use @samp{ssl-verify-client-cert? #t}. The file should
12373 contain the CA certificate(s) followed by the matching
12374 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
12375 Defaults to @samp{""}.
12378 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
12379 Require that CRL check succeeds for client certificates.
12380 Defaults to @samp{#t}.
12383 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
12384 Request client to send a certificate. If you also want to require
12385 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
12386 Defaults to @samp{#f}.
12389 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
12390 Which field from certificate to use for username. commonName and
12391 x500UniqueIdentifier are the usual choices. You'll also need to set
12392 @samp{auth-ssl-username-from-cert? #t}.
12393 Defaults to @samp{"commonName"}.
12396 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
12397 How often to regenerate the SSL parameters file. Generation is
12398 quite CPU intensive operation. The value is in hours, 0 disables
12399 regeneration entirely.
12400 Defaults to @samp{168}.
12403 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
12404 SSL protocols to use.
12405 Defaults to @samp{"!SSLv2"}.
12408 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
12409 SSL ciphers to use.
12410 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
12413 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
12414 SSL crypto device to use, for valid values run "openssl engine".
12415 Defaults to @samp{""}.
12418 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
12419 Address to use when sending rejection mails.
12420 %d expands to recipient domain.
12421 Defaults to @samp{"postmaster@@%d"}.
12424 @deftypevr {@code{dovecot-configuration} parameter} string hostname
12425 Hostname to use in various parts of sent mails (e.g. in Message-Id)
12426 and in LMTP replies. Default is the system's real hostname@@domain.
12427 Defaults to @samp{""}.
12430 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
12431 If user is over quota, return with temporary failure instead of
12433 Defaults to @samp{#f}.
12436 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
12437 Binary to use for sending mails.
12438 Defaults to @samp{"/usr/sbin/sendmail"}.
12441 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
12442 If non-empty, send mails via this SMTP host[:port] instead of
12444 Defaults to @samp{""}.
12447 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
12448 Subject: header to use for rejection mails. You can use the same
12449 variables as for @samp{rejection-reason} below.
12450 Defaults to @samp{"Rejected: %s"}.
12453 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
12454 Human readable error message for rejection mails. You can use
12467 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
12470 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
12471 Delimiter character between local-part and detail in email
12473 Defaults to @samp{"+"}.
12476 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
12477 Header where the original recipient address (SMTP's RCPT TO:
12478 address) is taken from if not available elsewhere. With dovecot-lda -a
12479 parameter overrides this. A commonly used header for this is
12481 Defaults to @samp{""}.
12484 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
12485 Should saving a mail to a nonexistent mailbox automatically create
12487 Defaults to @samp{#f}.
12490 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
12491 Should automatically created mailboxes be also automatically
12493 Defaults to @samp{#f}.
12496 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
12497 Maximum IMAP command line length. Some clients generate very long
12498 command lines with huge mailboxes, so you may need to raise this if you
12499 get "Too long argument" or "IMAP command line too large" errors
12501 Defaults to @samp{64000}.
12504 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
12505 IMAP logout format string:
12508 total number of bytes read from client
12510 total number of bytes sent to client.
12512 Defaults to @samp{"in=%i out=%o"}.
12515 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
12516 Override the IMAP CAPABILITY response. If the value begins with '+',
12517 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
12518 Defaults to @samp{""}.
12521 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
12522 How long to wait between "OK Still here" notifications when client
12524 Defaults to @samp{"2 mins"}.
12527 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
12528 ID field names and values to send to clients. Using * as the value
12529 makes Dovecot use the default value. The following fields have default
12530 values currently: name, version, os, os-version, support-url,
12532 Defaults to @samp{""}.
12535 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
12536 ID fields sent by client to log. * means everything.
12537 Defaults to @samp{""}.
12540 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
12541 Workarounds for various client bugs:
12544 @item delay-newmail
12545 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
12546 CHECK commands. Some clients ignore them otherwise, for example OSX
12547 Mail (<v2.1). Outlook Express breaks more badly though, without this it
12548 may show user "Message no longer in server" errors. Note that OE6
12549 still breaks even with this workaround if synchronization is set to
12552 @item tb-extra-mailbox-sep
12553 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
12554 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
12555 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
12557 @item tb-lsub-flags
12558 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
12559 This makes Thunderbird realize they aren't selectable and show them
12560 greyed out, instead of only later giving "not selectable" popup error.
12562 Defaults to @samp{()}.
12565 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
12566 Host allowed in URLAUTH URLs sent by client. "*" allows all.
12567 Defaults to @samp{""}.
12571 Whew! Lots of configuration options. The nice thing about it though is
12572 that GuixSD has a complete interface to Dovecot's configuration
12573 language. This allows not only a nice way to declare configurations,
12574 but also offers reflective capabilities as well: users can write code to
12575 inspect and transform configurations from within Scheme.
12577 However, it could be that you just want to get a @code{dovecot.conf} up
12578 and running. In that case, you can pass an
12579 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
12580 @code{dovecot-service}. As its name indicates, an opaque configuration
12581 does not have easy reflective capabilities.
12583 Available @code{opaque-dovecot-configuration} fields are:
12585 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
12586 The dovecot package.
12589 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
12590 The contents of the @code{dovecot.conf}, as a string.
12593 For example, if your @code{dovecot.conf} is just the empty string, you
12594 could instantiate a dovecot service like this:
12597 (dovecot-service #:config
12598 (opaque-dovecot-configuration
12602 @subsubheading OpenSMTPD Service
12604 @deffn {Scheme Variable} opensmtpd-service-type
12605 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
12606 service, whose value should be an @code{opensmtpd-configuration} object
12607 as in this example:
12610 (service opensmtpd-service-type
12611 (opensmtpd-configuration
12612 (config-file (local-file "./my-smtpd.conf"))))
12616 @deftp {Data Type} opensmtpd-configuration
12617 Data type representing the configuration of opensmtpd.
12620 @item @code{package} (default: @var{opensmtpd})
12621 Package object of the OpenSMTPD SMTP server.
12623 @item @code{config-file} (default: @var{%default-opensmtpd-file})
12624 File-like object of the OpenSMTPD configuration file to use. By default
12625 it listens on the loopback network interface, and allows for mail from
12626 users and daemons on the local machine, as well as permitting email to
12627 remote servers. Run @command{man smtpd.conf} for more information.
12632 @subsubheading Exim Service
12634 @deffn {Scheme Variable} exim-service-type
12635 This is the type of the @uref{https://exim.org, Exim} service, whose value
12636 should be an @code{exim-configuration} object as in this example:
12639 (service exim-service-type
12640 (exim-configuration
12641 (config-file (local-file "./my-exim.conf"))
12642 (aliases '(("postmaster" "bob")
12643 ("bob" "bob@@example.com" "bob@@example2.com")))))
12647 @deftp {Data Type} exim-configuration
12648 Data type representing the configuration of exim.
12651 @item @code{package} (default: @var{exim})
12652 Package object of the Exim server.
12654 @item @code{config-file} (default: @code{#f})
12655 File-like object of the Exim configuration file to use. If its value is
12656 @code{#f} then use the default configuration file from the package
12657 provided in @code{package}. The resulting configuration file is loaded
12658 after setting the @code{exim_user} and @code{exim_group} configuration
12661 @item @code{aliases} (default: @code{'()})
12662 List of aliases to use when delivering mail on this system. The
12663 @code{car} of each list is used to match incoming mail, with the
12664 @code{cdr} of each list designating how to deliver it. There may be many
12665 delivery methods provided, in which case the mail is delivered to them
12671 @node Messaging Services
12672 @subsubsection Messaging Services
12677 The @code{(gnu services messaging)} module provides Guix service
12678 definitions for messaging services: currently only Prosody is supported.
12680 @subsubheading Prosody Service
12682 @deffn {Scheme Variable} prosody-service-type
12683 This is the type for the @uref{http://prosody.im, Prosody XMPP
12684 communication server}. Its value must be a @code{prosody-configuration}
12685 record as in this example:
12688 (service prosody-service-type
12689 (prosody-configuration
12690 (modules-enabled (cons "groups" %default-modules-enabled))
12693 (int-component-configuration
12694 (hostname "conference.example.net")
12696 (mod-muc (mod-muc-configuration)))))
12699 (virtualhost-configuration
12700 (domain "example.net"))))))
12703 See below for details about @code{prosody-configuration}.
12707 By default, Prosody does not need much configuration. Only one
12708 @code{virtualhosts} field is needed: it specifies the domain you wish
12711 Prosodyctl will help you generate X.509 certificates and keys:
12714 prosodyctl cert request example.net
12717 The available configuration parameters follow. Each parameter
12718 definition is preceded by its type; for example, @samp{string-list foo}
12719 indicates that the @code{foo} parameter should be specified as a list of
12720 strings. Types starting with @code{maybe-} denote parameters that won't
12721 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
12723 There is also a way to specify the configuration as a string, if you
12724 have an old @code{prosody.cfg.lua} file that you want to port over from
12725 some other system; see the end for more details.
12727 @c The following documentation was initially generated by
12728 @c (generate-documentation) in (gnu services messaging). Manually maintained
12729 @c documentation is better, so we shouldn't hesitate to edit below as
12730 @c needed. However if the change you want to make to this documentation
12731 @c can be done in an automated way, it's probably easier to change
12732 @c (generate-documentation) than to make it below and have to deal with
12733 @c the churn as Prosody updates.
12735 Available @code{prosody-configuration} fields are:
12737 @deftypevr {@code{prosody-configuration} parameter} package prosody
12738 The Prosody package.
12741 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
12742 Location of the Prosody data storage directory. See
12743 @url{http://prosody.im/doc/configure}.
12744 Defaults to @samp{"/var/lib/prosody"}.
12747 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
12748 Additional plugin directories. They are searched in all the specified
12749 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
12750 Defaults to @samp{()}.
12753 @deftypevr {@code{prosody-configuration} parameter} string-list admins
12754 This is a list of accounts that are admins for the server. Note that you
12755 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
12756 @url{http://prosody.im/doc/creating_accounts}.
12757 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
12758 Defaults to @samp{()}.
12761 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
12762 Enable use of libevent for better performance under high load. See
12763 @url{http://prosody.im/doc/libevent}.
12764 Defaults to @samp{#f}.
12767 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
12768 This is the list of modules Prosody will load on startup. It looks for
12769 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
12770 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
12771 Defaults to @samp{%default-modules-enabled}.
12774 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
12775 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
12776 should you want to disable them then add them to this list.
12777 Defaults to @samp{()}.
12780 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
12781 Path to a text file where the shared groups are defined. If this path is
12782 empty then @samp{mod_groups} does nothing. See
12783 @url{http://prosody.im/doc/modules/mod_groups}.
12784 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
12787 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
12788 Disable account creation by default, for security. See
12789 @url{http://prosody.im/doc/creating_accounts}.
12790 Defaults to @samp{#f}.
12793 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
12794 These are the SSL/TLS-related settings. Most of them are disabled so to
12795 use Prosody's defaults. If you do not completely understand these options, do
12796 not add them to your config, it is easy to lower the security of your server
12797 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
12799 Available @code{ssl-configuration} fields are:
12801 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
12802 This determines what handshake to use.
12805 @deftypevr {@code{ssl-configuration} parameter} file-name key
12806 Path to your private key file, relative to @code{/etc/prosody}.
12807 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
12810 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
12811 Path to your certificate file, relative to @code{/etc/prosody}.
12812 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
12815 @deftypevr {@code{ssl-configuration} parameter} file-name capath
12816 Path to directory containing root certificates that you wish Prosody to
12817 trust when verifying the certificates of remote servers.
12818 Defaults to @samp{"/etc/ssl/certs"}.
12821 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
12822 Path to a file containing root certificates that you wish Prosody to trust.
12823 Similar to @code{capath} but with all certificates concatenated together.
12826 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
12827 A list of verification options (these mostly map to OpenSSL's
12828 @code{set_verify()} flags).
12831 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
12832 A list of general options relating to SSL/TLS. These map to OpenSSL's
12833 @code{set_options()}. For a full list of options available in LuaSec, see the
12837 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
12838 How long a chain of certificate authorities to check when looking for a
12839 trusted root certificate.
12842 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
12843 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
12844 clients, and in what order.
12847 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
12848 A path to a file containing parameters for Diffie-Hellman key exchange. You
12849 can create such a file with:
12850 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
12853 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
12854 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
12855 @samp{"secp384r1"}.
12858 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
12859 A list of "extra" verification options.
12862 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
12863 Password for encrypted private keys.
12868 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
12869 Whether to force all client-to-server connections to be encrypted or not.
12870 See @url{http://prosody.im/doc/modules/mod_tls}.
12871 Defaults to @samp{#f}.
12874 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
12875 Whether to force all server-to-server connections to be encrypted or not.
12876 See @url{http://prosody.im/doc/modules/mod_tls}.
12877 Defaults to @samp{#f}.
12880 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
12881 Whether to require encryption and certificate authentication. This
12882 provides ideal security, but requires servers you communicate with to support
12883 encryption AND present valid, trusted certificates. See
12884 @url{http://prosody.im/doc/s2s#security}.
12885 Defaults to @samp{#f}.
12888 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
12889 Many servers don't support encryption or have invalid or self-signed
12890 certificates. You can list domains here that will not be required to
12891 authenticate using certificates. They will be authenticated using DNS. See
12892 @url{http://prosody.im/doc/s2s#security}.
12893 Defaults to @samp{()}.
12896 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
12897 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
12898 valid certificates for some domains by specifying a list here. See
12899 @url{http://prosody.im/doc/s2s#security}.
12900 Defaults to @samp{()}.
12903 @deftypevr {@code{prosody-configuration} parameter} string authentication
12904 Select the authentication backend to use. The default provider stores
12905 passwords in plaintext and uses Prosody's configured data storage to store the
12906 authentication data. If you do not trust your server please see
12907 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
12908 about using the hashed backend. See also
12909 @url{http://prosody.im/doc/authentication}
12910 Defaults to @samp{"internal_plain"}.
12913 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
12914 Set logging options. Advanced logging configuration is not yet supported
12915 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
12916 Defaults to @samp{"*syslog"}.
12919 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
12920 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
12921 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
12924 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
12925 A host in Prosody is a domain on which user accounts can be created. For
12926 example if you want your users to have addresses like
12927 @samp{"john.smith@@example.com"} then you need to add a host
12928 @samp{"example.com"}. All options in this list will apply only to this host.
12930 Note: the name "virtual" host is used in configuration to avoid confusion with
12931 the actual physical host that Prosody is installed on. A single Prosody
12932 instance can serve many domains, each one defined as a VirtualHost entry in
12933 Prosody's configuration. Conversely a server that hosts a single domain would
12934 have just one VirtualHost entry.
12936 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
12938 Available @code{virtualhost-configuration} fields are:
12940 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:
12941 @deftypevr {@code{virtualhost-configuration} parameter} string domain
12942 Domain you wish Prosody to serve.
12947 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
12948 Components are extra services on a server which are available to clients,
12949 usually on a subdomain of the main server (such as
12950 @samp{"mycomponent.example.com"}). Example components might be chatroom
12951 servers, user directories, or gateways to other protocols.
12953 Internal components are implemented with Prosody-specific plugins. To add an
12954 internal component, you simply fill the hostname field, and the plugin you wish
12955 to use for the component.
12957 See @url{http://prosody.im/doc/components}.
12958 Defaults to @samp{()}.
12960 Available @code{int-component-configuration} fields are:
12962 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:
12963 @deftypevr {@code{int-component-configuration} parameter} string hostname
12964 Hostname of the component.
12967 @deftypevr {@code{int-component-configuration} parameter} string plugin
12968 Plugin you wish to use for the component.
12971 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
12972 Multi-user chat (MUC) is Prosody's module for allowing you to create
12973 hosted chatrooms/conferences for XMPP users.
12975 General information on setting up and using multi-user chatrooms can be found
12976 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
12977 which you should read if you are new to XMPP chatrooms.
12979 See also @url{http://prosody.im/doc/modules/mod_muc}.
12981 Available @code{mod-muc-configuration} fields are:
12983 @deftypevr {@code{mod-muc-configuration} parameter} string name
12984 The name to return in service discovery responses.
12985 Defaults to @samp{"Prosody Chatrooms"}.
12988 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
12989 If @samp{#t}, this will only allow admins to create new chatrooms.
12990 Otherwise anyone can create a room. The value @samp{"local"} restricts room
12991 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
12992 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
12993 restricts to service administrators only.
12994 Defaults to @samp{#f}.
12997 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
12998 Maximum number of history messages that will be sent to the member that has
12999 just joined the room.
13000 Defaults to @samp{20}.
13007 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13008 External components use XEP-0114, which most standalone components
13009 support. To add an external component, you simply fill the hostname field. See
13010 @url{http://prosody.im/doc/components}.
13011 Defaults to @samp{()}.
13013 Available @code{ext-component-configuration} fields are:
13015 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:
13016 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13017 Password which the component will use to log in.
13020 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13021 Hostname of the component.
13026 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13027 Port(s) Prosody listens on for component connections.
13030 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13031 Interface Prosody listens on for component connections.
13032 Defaults to @samp{"127.0.0.1"}.
13035 It could be that you just want to get a @code{prosody.cfg.lua}
13036 up and running. In that case, you can pass an
13037 @code{opaque-prosody-configuration} record as the value of
13038 @code{prosody-service-type}. As its name indicates, an opaque configuration
13039 does not have easy reflective capabilities.
13040 Available @code{opaque-prosody-configuration} fields are:
13042 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13043 The prosody package.
13046 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13047 The contents of the @code{prosody.cfg.lua} to use.
13050 For example, if your @code{prosody.cfg.lua} is just the empty
13051 string, you could instantiate a prosody service like this:
13054 (service prosody-service-type
13055 (opaque-prosody-configuration
13056 (prosody.cfg.lua "")))
13059 @node Kerberos Services
13060 @subsubsection Kerberos Services
13063 The @code{(gnu services kerberos)} module provides services relating to
13064 the authentication protocol @dfn{Kerberos}.
13066 @subsubheading Krb5 Service
13068 Programs using a Kerberos client library normally
13069 expect a configuration file in @file{/etc/krb5.conf}.
13070 This service generates such a file from a definition provided in the
13071 operating system declaration.
13072 It does not cause any daemon to be started.
13074 No ``keytab'' files are provided by this service---you must explicitly create them.
13075 This service is known to work with the MIT client library, @code{mit-krb5}.
13076 Other implementations have not been tested.
13078 @defvr {Scheme Variable} krb5-service-type
13079 A service type for Kerberos 5 clients.
13083 Here is an example of its use:
13085 (service krb5-service-type
13086 (krb5-configuration
13087 (default-realm "EXAMPLE.COM")
13088 (allow-weak-crypto? #t)
13091 (name "EXAMPLE.COM")
13092 (admin-server "groucho.example.com")
13093 (kdc "karl.example.com"))
13096 (admin-server "kerb-admin.argrx.edu")
13097 (kdc "keys.argrx.edu"))))))
13101 This example provides a Kerberos@tie{}5 client configuration which:
13103 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13104 of which have distinct administration servers and key distribution centers;
13105 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13106 specified by clients;
13107 @item Accepts services which only support encryption types known to be weak.
13110 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13111 Only the most commonly used ones are described here.
13112 For a full list, and more detailed explanation of each, see the MIT
13113 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13117 @deftp {Data Type} krb5-realm
13118 @cindex realm, kerberos
13121 This field is a string identifying the name of the realm.
13122 A common convention is to use the fully qualified DNS name of your organization,
13123 converted to upper case.
13125 @item @code{admin-server}
13126 This field is a string identifying the host where the administration server is
13130 This field is a string identifying the key distribution center
13135 @deftp {Data Type} krb5-configuration
13138 @item @code{allow-weak-crypto?} (default: @code{#f})
13139 If this flag is @code{#t} then services which only offer encryption algorithms
13140 known to be weak will be accepted.
13142 @item @code{default-realm} (default: @code{#f})
13143 This field should be a string identifying the default Kerberos
13144 realm for the client.
13145 You should set this field to the name of your Kerberos realm.
13146 If this value is @code{#f}
13147 then a realm must be specified with every Kerberos principal when invoking programs
13148 such as @command{kinit}.
13150 @item @code{realms}
13151 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13153 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13159 @subsubheading PAM krb5 Service
13162 The @code{pam-krb5} service allows for login authentication and password
13163 management via Kerberos.
13164 You will need this service if you want PAM enabled applications to authenticate
13165 users using Kerberos.
13167 @defvr {Scheme Variable} pam-krb5-service-type
13168 A service type for the Kerberos 5 PAM module.
13171 @deftp {Data Type} pam-krb5-configuration
13172 Data type representing the configuration of the Kerberos 5 PAM module
13173 This type has the following parameters:
13175 @item @code{pam-krb5} (default: @code{pam-krb5})
13176 The pam-krb5 package to use.
13178 @item @code{minimum-uid} (default: @code{1000})
13179 The smallest user ID for which Kerberos authentications should be attempted.
13180 Local accounts with lower values will silently fail to authenticate.
13186 @subsubsection Web Services
13191 The @code{(gnu services web)} module provides the following service:
13193 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
13194 [#:log-directory ``/var/log/nginx''] @
13195 [#:run-directory ``/var/run/nginx''] @
13196 [#:server-list '()] @
13197 [#:upstream-list '()] @
13198 [#:config-file @code{#f}]
13200 Return a service that runs @var{nginx}, the nginx web server.
13202 The nginx daemon loads its runtime configuration from @var{config-file}.
13203 Log files are written to @var{log-directory} and temporary runtime data
13204 files are written to @var{run-directory}. For proper operation, these
13205 arguments should match what is in @var{config-file} to ensure that the
13206 directories are created when the service is activated.
13208 As an alternative to using a @var{config-file}, @var{server-list} can be
13209 used to specify the list of @dfn{server blocks} required on the host and
13210 @var{upstream-list} can be used to specify a list of @dfn{upstream
13211 blocks} to configure. For this to work, use the default value for
13216 @deffn {Scheme Variable} nginx-service-type
13217 This is type for the nginx web server.
13219 This service can be extended to add server blocks in addition to the
13220 default one, as in this example:
13223 (simple-service 'my-extra-server nginx-service-type
13224 (list (nginx-server-configuration
13226 (root "/srv/http/extra-website"))))
13230 @deftp {Data Type} nginx-server-configuration
13231 Data type representing the configuration of an nginx server block.
13232 This type has the following parameters:
13235 @item @code{http-port} (default: @code{80})
13236 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
13237 nginx should not listen for HTTP (non secure) connection for this
13238 @dfn{server block}.
13240 @item @code{https-port} (default: @code{443})
13241 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
13242 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
13244 Note that nginx can listen for HTTP and HTTPS connections in the same
13245 @dfn{server block}.
13247 @item @code{server-name} (default: @code{(list 'default)})
13248 A list of server names this server represents. @code{'default} represents the
13249 default server for connections matching no other server.
13251 @item @code{root} (default: @code{"/srv/http"})
13252 Root of the website nginx will serve.
13254 @item @code{locations} (default: @code{'()})
13255 A list of @dfn{nginx-location-configuration} or
13256 @dfn{nginx-named-location-configuration} records to use within this
13259 @item @code{index} (default: @code{(list "index.html")})
13260 Index files to look for when clients ask for a directory. If it cannot be found,
13261 Nginx will send the list of files in the directory.
13263 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
13264 Where to find the certificate for secure connections. Set it to @code{#f} if
13265 you don't have a certificate or you don't want to use HTTPS.
13267 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
13268 Where to find the private key for secure connections. Set it to @code{#f} if
13269 you don't have a key or you don't want to use HTTPS.
13271 @item @code{server-tokens?} (default: @code{#f})
13272 Whether the server should add its configuration to response.
13278 @subsubsection VPN Services
13279 @cindex VPN (virtual private network)
13280 @cindex virtual private network (VPN)
13282 The @code{(gnu services vpn)} module provides services related to
13283 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
13284 your machine to connect to a VPN, and a @emph{servire} service for your machine
13285 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
13287 @deffn {Scheme Procedure} openvpn-client-service @
13288 [#:config (openvpn-client-configuration)]
13290 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
13293 @deffn {Scheme Procedure} openvpn-server-service @
13294 [#:config (openvpn-server-configuration)]
13296 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
13298 Both can be run simultaneously.
13301 @c %automatically generated documentation
13303 Available @code{openvpn-client-configuration} fields are:
13305 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
13306 The OpenVPN package.
13310 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
13311 The OpenVPN pid file.
13313 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
13317 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
13318 The protocol (UDP or TCP) used to open a channel between clients and
13321 Defaults to @samp{udp}.
13325 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
13326 The device type used to represent the VPN connection.
13328 Defaults to @samp{tun}.
13332 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
13333 The certificate authority to check connections against.
13335 Defaults to @samp{"/etc/openvpn/ca.crt"}.
13339 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
13340 The certificate of the machine the daemon is running on. It should be
13341 signed by the authority given in @code{ca}.
13343 Defaults to @samp{"/etc/openvpn/client.crt"}.
13347 @deftypevr {@code{openvpn-client-configuration} parameter} string key
13348 The key of the machine the daemon is running on. It must be the key whose
13349 certificate is @code{cert}.
13351 Defaults to @samp{"/etc/openvpn/client.key"}.
13355 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
13356 Whether to use the lzo compression algorithm.
13358 Defaults to @samp{#t}.
13362 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
13363 Don't re-read key files across SIGUSR1 or --ping-restart.
13365 Defaults to @samp{#t}.
13369 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
13370 Don't close and reopen TUN/TAP device or run up/down scripts across
13371 SIGUSR1 or --ping-restart restarts.
13373 Defaults to @samp{#t}.
13377 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
13380 Defaults to @samp{3}.
13384 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
13385 Add an additional layer of HMAC authentication on top of the TLS control
13386 channel to protect against DoS attacks.
13388 Defaults to @samp{#f}.
13392 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
13393 Whether to check the server certificate has server usage extension.
13395 Defaults to @samp{#t}.
13399 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
13400 Bind to a specific local port number.
13402 Defaults to @samp{#f}.
13406 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
13407 Retry resolving server address.
13409 Defaults to @samp{#t}.
13413 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
13414 A list of remote servers to connect to.
13416 Defaults to @samp{()}.
13418 Available @code{openvpn-remote-configuration} fields are:
13420 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
13423 Defaults to @samp{"my-server"}.
13427 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
13428 Port number the server listens to.
13430 Defaults to @samp{1194}.
13435 @c %end of automatic openvpn-client documentation
13437 @c %automatically generated documentation
13439 Available @code{openvpn-server-configuration} fields are:
13441 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
13442 The OpenVPN package.
13446 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
13447 The OpenVPN pid file.
13449 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
13453 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
13454 The protocol (UDP or TCP) used to open a channel between clients and
13457 Defaults to @samp{udp}.
13461 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
13462 The device type used to represent the VPN connection.
13464 Defaults to @samp{tun}.
13468 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
13469 The certificate authority to check connections against.
13471 Defaults to @samp{"/etc/openvpn/ca.crt"}.
13475 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
13476 The certificate of the machine the daemon is running on. It should be
13477 signed by the authority given in @code{ca}.
13479 Defaults to @samp{"/etc/openvpn/client.crt"}.
13483 @deftypevr {@code{openvpn-server-configuration} parameter} string key
13484 The key of the machine the daemon is running on. It must be the key whose
13485 certificate is @code{cert}.
13487 Defaults to @samp{"/etc/openvpn/client.key"}.
13491 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
13492 Whether to use the lzo compression algorithm.
13494 Defaults to @samp{#t}.
13498 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
13499 Don't re-read key files across SIGUSR1 or --ping-restart.
13501 Defaults to @samp{#t}.
13505 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
13506 Don't close and reopen TUN/TAP device or run up/down scripts across
13507 SIGUSR1 or --ping-restart restarts.
13509 Defaults to @samp{#t}.
13513 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
13516 Defaults to @samp{3}.
13520 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
13521 Add an additional layer of HMAC authentication on top of the TLS control
13522 channel to protect against DoS attacks.
13524 Defaults to @samp{#f}.
13528 @deftypevr {@code{openvpn-server-configuration} parameter} number port
13529 Specifies the port number on which the server listens.
13531 Defaults to @samp{1194}.
13535 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
13536 An ip and mask specifying the subnet inside the virtual network.
13538 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
13542 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
13543 A CIDR notation specifying the IPv6 subnet inside the virtual network.
13545 Defaults to @samp{#f}.
13549 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
13550 The Diffie-Hellman parameters file.
13552 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
13556 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
13557 The file that records client IPs.
13559 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
13563 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
13564 When true, the server will act as a gateway for its clients.
13566 Defaults to @samp{#f}.
13570 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
13571 When true, clients are allowed to talk to each other inside the VPN.
13573 Defaults to @samp{#f}.
13577 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
13578 Causes ping-like messages to be sent back and forth over the link so
13579 that each side knows when the other side has gone down. @code{keepalive}
13580 requires a pair. The first element is the period of the ping sending,
13581 and the second element is the timeout before considering the other side
13586 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
13587 The maximum number of clients.
13589 Defaults to @samp{100}.
13593 @deftypevr {@code{openvpn-server-configuration} parameter} string status
13594 The status file. This file shows a small report on current connection.
13595 It is truncated and rewritten every minute.
13597 Defaults to @samp{"/var/run/openvpn/status"}.
13601 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
13602 The list of configuration for some clients.
13604 Defaults to @samp{()}.
13606 Available @code{openvpn-ccd-configuration} fields are:
13608 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
13611 Defaults to @samp{"client"}.
13615 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
13618 Defaults to @samp{#f}.
13622 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
13625 Defaults to @samp{#f}.
13632 @c %end of automatic openvpn-server documentation
13635 @deftp {Data Type} nginx-upstream-configuration
13636 Data type representing the configuration of an nginx @code{upstream}
13637 block. This type has the following parameters:
13641 Name for this group of servers.
13643 @item @code{servers}
13644 Specify the addresses of the servers in the group. The address can be
13645 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
13646 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
13647 prefix @samp{unix:}. For addresses using an IP address or domain name,
13648 the default port is 80, and a different port can be specified
13654 @deftp {Data Type} nginx-location-configuration
13655 Data type representing the configuration of an nginx @code{location}
13656 block. This type has the following parameters:
13660 URI which this location block matches.
13662 @anchor{nginx-location-configuration body}
13664 Body of the location block, specified as a string. This can contain many
13665 configuration directives. For example, to pass requests to a upstream
13666 server group defined using an @code{nginx-upstream-configuration} block,
13667 the following directive would be specified in the body @samp{proxy_pass
13668 http://upstream-name;}.
13673 @deftp {Data Type} nginx-named-location-configuration
13674 Data type representing the configuration of an nginx named location
13675 block. Named location blocks are used for request redirection, and not
13676 used for regular request processing. This type has the following
13681 Name to identify this location block.
13684 @xref{nginx-location-configuration body}, as the body for named location
13685 blocks can be used in a similar way to the
13686 @code{nginx-location-configuration body}. One restriction is that the
13687 body of a named location block cannot contain location blocks.
13692 @node Network File System
13693 @subsubsection Network File System
13696 The @code{(gnu services nfs)} module provides the following services,
13697 which are most commonly used in relation to mounting or exporting
13698 directory trees as @dfn{network file systems} (NFS).
13700 @subsubheading RPC Bind Service
13703 The RPC Bind service provides a facility to map program numbers into
13704 universal addresses.
13705 Many NFS related services use this facility. Hence it is automatically
13706 started when a dependent service starts.
13708 @defvr {Scheme Variable} rpcbind-service-type
13709 A service type for the RPC portmapper daemon.
13713 @deftp {Data Type} rpcbind-configuration
13714 Data type representing the configuration of the RPC Bind Service.
13715 This type has the following parameters:
13717 @item @code{rpcbind} (default: @code{rpcbind})
13718 The rpcbind package to use.
13720 @item @code{warm-start?} (default: @code{#t})
13721 If this parameter is @code{#t}, then the daemon will read a
13722 state file on startup thus reloading state information saved by a previous
13728 @subsubheading Pipefs Pseudo File System
13732 The pipefs file system is used to transfer NFS related data
13733 between the kernel and user space programs.
13735 @defvr {Scheme Variable} pipefs-service-type
13736 A service type for the pipefs pseudo file system.
13739 @deftp {Data Type} pipefs-configuration
13740 Data type representing the configuration of the pipefs pseudo file system service.
13741 This type has the following parameters:
13743 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13744 The directory to which the file system is to be attached.
13749 @subsubheading GSS Daemon Service
13752 @cindex global security system
13754 The @dfn{global security system} (GSS) daemon provides strong security for RPC
13756 Before exchanging RPC requests an RPC client must establish a security
13757 context. Typically this is done using the Kerberos command @command{kinit}
13758 or automatically at login time using PAM services (@pxref{Kerberos Services}).
13760 @defvr {Scheme Variable} gss-service-type
13761 A service type for the Global Security System (GSS) daemon.
13764 @deftp {Data Type} gss-configuration
13765 Data type representing the configuration of the GSS daemon service.
13766 This type has the following parameters:
13768 @item @code{nfs-utils} (default: @code{nfs-utils})
13769 The package in which the @command{rpc.gssd} command is to be found.
13771 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13772 The directory where the pipefs file system is mounted.
13778 @subsubheading IDMAP Daemon Service
13780 @cindex name mapper
13782 The idmap daemon service provides mapping between user IDs and user names.
13783 Typically it is required in order to access file systems mounted via NFSv4.
13785 @defvr {Scheme Variable} idmap-service-type
13786 A service type for the Identity Mapper (IDMAP) daemon.
13789 @deftp {Data Type} idmap-configuration
13790 Data type representing the configuration of the IDMAP daemon service.
13791 This type has the following parameters:
13793 @item @code{nfs-utils} (default: @code{nfs-utils})
13794 The package in which the @command{rpc.idmapd} command is to be found.
13796 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13797 The directory where the pipefs file system is mounted.
13799 @item @code{domain} (default: @code{#f})
13800 The local NFSv4 domain name.
13801 This must be a string or @code{#f}.
13802 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
13807 @node Continuous Integration
13808 @subsubsection Continuous Integration
13810 @cindex continuous integration
13811 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
13812 integration tool for Guix. It can be used both for development and for
13813 providing substitutes to others (@pxref{Substitutes}).
13815 The @code{(gnu services cuirass)} module provides the following service.
13817 @defvr {Scheme Procedure} cuirass-service-type
13818 The type of the Cuirass service. Its value must be a
13819 @code{cuirass-configuration} object, as described below.
13822 To add build jobs, you have to set the @code{specifications} field of
13823 the configuration. Here is an example of a service defining a build job
13824 based on a specification that can be found in Cuirass source tree. This
13825 service polls the Guix repository and builds a subset of the Guix
13826 packages, as prescribed in the @file{gnu-system.scm} example spec:
13829 (let ((spec #~((#:name . "guix")
13830 (#:url . "git://git.savannah.gnu.org/guix.git")
13831 (#:load-path . ".")
13833 ;; Here we must provide an absolute file name.
13834 ;; We take jobs from one of the examples provided
13836 (#:file . #$(file-append
13838 "/tests/gnu-system.scm"))
13840 (#:proc . hydra-jobs)
13841 (#:arguments (subset . "hello"))
13842 (#:branch . "master"))))
13843 (service cuirass-service-type
13844 (cuirass-configuration
13845 (specifications #~(list #$spec)))))
13848 While information related to build jobs is located directly in the
13849 specifications, global settings for the @command{cuirass} process are
13850 accessible in other @code{cuirass-configuration} fields.
13852 @deftp {Data Type} cuirass-configuration
13853 Data type representing the configuration of Cuirass.
13856 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
13857 Location of the log file.
13859 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
13860 Location of the repository cache.
13862 @item @code{user} (default: @code{"cuirass"})
13863 Owner of the @code{cuirass} process.
13865 @item @code{group} (default: @code{"cuirass"})
13866 Owner's group of the @code{cuirass} process.
13868 @item @code{interval} (default: @code{60})
13869 Number of seconds between the poll of the repositories followed by the
13872 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
13873 Location of sqlite database which contains the build results and previously
13874 added specifications.
13876 @item @code{port} (default: @code{8080})
13877 Port number used by the HTTP server.
13879 @item @code{specifications} (default: @code{#~'()})
13880 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
13881 where a specification is an association list
13882 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
13883 keys are keywords (@code{#:keyword-example}) as shown in the example
13886 @item @code{use-substitutes?} (default: @code{#f})
13887 This allows using substitutes to avoid building every dependencies of a job
13890 @item @code{one-shot?} (default: @code{#f})
13891 Only evaluate specifications and build derivations once.
13893 @item @code{load-path} (default: @code{'()})
13894 This allows users to define their own packages and make them visible to
13895 cuirass as in @command{guix build} command.
13897 @item @code{cuirass} (default: @code{cuirass})
13898 The Cuirass package to use.
13902 @node Power management Services
13903 @subsubsection Power management Services
13905 @cindex power management with TLP
13906 The @code{(gnu services pm)} module provides a Guix service definition
13907 for the Linux power management tool TLP.
13909 TLP enables various powersaving modes in userspace and kernel.
13910 Contrary to @code{upower-service}, it is not a passive,
13911 monitoring tool, as it will apply custom settings each time a new power
13912 source is detected. More information can be found at
13913 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
13915 @deffn {Scheme Variable} tlp-service-type
13916 The service type for the TLP tool. Its value should be a valid
13917 TLP configuration (see below). To use the default settings, simply
13920 (service tlp-service-type)
13924 By default TLP does not need much configuration but most TLP parameters
13925 can be tweaked using @code{tlp-configuration}.
13927 Each parameter definition is preceded by its type; for example,
13928 @samp{boolean foo} indicates that the @code{foo} parameter
13929 should be specified as a boolean. Types starting with
13930 @code{maybe-} denote parameters that won't show up in TLP config file
13931 when their value is @code{'disabled}.
13933 @c The following documentation was initially generated by
13934 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
13935 @c documentation is better, so we shouldn't hesitate to edit below as
13936 @c needed. However if the change you want to make to this documentation
13937 @c can be done in an automated way, it's probably easier to change
13938 @c (generate-documentation) than to make it below and have to deal with
13939 @c the churn as TLP updates.
13941 Available @code{tlp-configuration} fields are:
13943 @deftypevr {@code{tlp-configuration} parameter} package tlp
13948 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
13949 Set to true if you wish to enable TLP.
13951 Defaults to @samp{#t}.
13955 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
13956 Default mode when no power supply can be detected. Alternatives are AC
13959 Defaults to @samp{"AC"}.
13963 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
13964 Number of seconds Linux kernel has to wait after the disk goes idle,
13965 before syncing on AC.
13967 Defaults to @samp{0}.
13971 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
13972 Same as @code{disk-idle-ac} but on BAT mode.
13974 Defaults to @samp{2}.
13978 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
13979 Dirty pages flushing periodicity, expressed in seconds.
13981 Defaults to @samp{15}.
13985 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
13986 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
13988 Defaults to @samp{60}.
13992 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
13993 CPU frequency scaling governor on AC mode. With intel_pstate driver,
13994 alternatives are powersave and performance. With acpi-cpufreq driver,
13995 alternatives are ondemand, powersave, performance and conservative.
13997 Defaults to @samp{disabled}.
14001 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
14002 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
14004 Defaults to @samp{disabled}.
14008 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
14009 Set the min available frequency for the scaling governor on AC.
14011 Defaults to @samp{disabled}.
14015 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
14016 Set the max available frequency for the scaling governor on AC.
14018 Defaults to @samp{disabled}.
14022 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
14023 Set the min available frequency for the scaling governor on BAT.
14025 Defaults to @samp{disabled}.
14029 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
14030 Set the max available frequency for the scaling governor on BAT.
14032 Defaults to @samp{disabled}.
14036 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
14037 Limit the min P-state to control the power dissipation of the CPU, in AC
14038 mode. Values are stated as a percentage of the available performance.
14040 Defaults to @samp{disabled}.
14044 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
14045 Limit the max P-state to control the power dissipation of the CPU, in AC
14046 mode. Values are stated as a percentage of the available performance.
14048 Defaults to @samp{disabled}.
14052 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
14053 Same as @code{cpu-min-perf-on-ac} on BAT mode.
14055 Defaults to @samp{disabled}.
14059 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
14060 Same as @code{cpu-max-perf-on-ac} on BAT mode.
14062 Defaults to @samp{disabled}.
14066 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
14067 Enable CPU turbo boost feature on AC mode.
14069 Defaults to @samp{disabled}.
14073 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
14074 Same as @code{cpu-boost-on-ac?} on BAT mode.
14076 Defaults to @samp{disabled}.
14080 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
14081 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
14082 used under light load conditions.
14084 Defaults to @samp{#f}.
14088 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
14089 Same as @code{sched-powersave-on-ac?} but on BAT mode.
14091 Defaults to @samp{#t}.
14095 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
14096 Enable Linux kernel NMI watchdog.
14098 Defaults to @samp{#f}.
14102 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
14103 For Linux kernels with PHC patch applied, change CPU voltages. An
14104 example value would be @samp{"F:V F:V F:V F:V"}.
14106 Defaults to @samp{disabled}.
14110 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
14111 Set CPU performance versus energy saving policy on AC. Alternatives are
14112 performance, normal, powersave.
14114 Defaults to @samp{"performance"}.
14118 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
14119 Same as @code{energy-perf-policy-ac} but on BAT mode.
14121 Defaults to @samp{"powersave"}.
14125 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
14130 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
14131 Hard disk advanced power management level.
14135 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
14136 Same as @code{disk-apm-bat} but on BAT mode.
14140 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
14141 Hard disk spin down timeout. One value has to be specified for each
14142 declared hard disk.
14144 Defaults to @samp{disabled}.
14148 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
14149 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
14151 Defaults to @samp{disabled}.
14155 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
14156 Select IO scheduler for disk devices. One value has to be specified for
14157 each declared hard disk. Example alternatives are cfq, deadline and
14160 Defaults to @samp{disabled}.
14164 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
14165 SATA aggressive link power management (ALPM) level. Alternatives are
14166 min_power, medium_power, max_performance.
14168 Defaults to @samp{"max_performance"}.
14172 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
14173 Same as @code{sata-linkpwr-ac} but on BAT mode.
14175 Defaults to @samp{"min_power"}.
14179 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
14180 Exclude specified SATA host devices for link power management.
14182 Defaults to @samp{disabled}.
14186 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
14187 Enable Runtime Power Management for AHCI controller and disks on AC
14190 Defaults to @samp{disabled}.
14194 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
14195 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
14197 Defaults to @samp{disabled}.
14201 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
14202 Seconds of inactivity before disk is suspended.
14204 Defaults to @samp{15}.
14208 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
14209 PCI Express Active State Power Management level. Alternatives are
14210 default, performance, powersave.
14212 Defaults to @samp{"performance"}.
14216 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
14217 Same as @code{pcie-aspm-ac} but on BAT mode.
14219 Defaults to @samp{"powersave"}.
14223 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
14224 Radeon graphics clock speed level. Alternatives are low, mid, high,
14227 Defaults to @samp{"high"}.
14231 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
14232 Same as @code{radeon-power-ac} but on BAT mode.
14234 Defaults to @samp{"low"}.
14238 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
14239 Radeon dynamic power management method (DPM). Alternatives are battery,
14242 Defaults to @samp{"performance"}.
14246 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
14247 Same as @code{radeon-dpm-state-ac} but on BAT mode.
14249 Defaults to @samp{"battery"}.
14253 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
14254 Radeon DPM performance level. Alternatives are auto, low, high.
14256 Defaults to @samp{"auto"}.
14260 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
14261 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
14263 Defaults to @samp{"auto"}.
14267 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
14268 Wifi power saving mode.
14270 Defaults to @samp{#f}.
14274 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
14275 Same as @code{wifi-power-ac?} but on BAT mode.
14277 Defaults to @samp{#t}.
14281 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
14282 Disable wake on LAN.
14284 Defaults to @samp{#t}.
14288 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
14289 Timeout duration in seconds before activating audio power saving on
14290 Intel HDA and AC97 devices. A value of 0 disables power saving.
14292 Defaults to @samp{0}.
14296 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
14297 Same as @code{sound-powersave-ac} but on BAT mode.
14299 Defaults to @samp{1}.
14303 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
14304 Disable controller in powersaving mode on Intel HDA devices.
14306 Defaults to @samp{#t}.
14310 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
14311 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
14312 powered on again by releasing (and reinserting) the eject lever or by
14313 pressing the disc eject button on newer models.
14315 Defaults to @samp{#f}.
14319 @deftypevr {@code{tlp-configuration} parameter} string bay-device
14320 Name of the optical drive device to power off.
14322 Defaults to @samp{"sr0"}.
14326 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
14327 Runtime Power Management for PCI(e) bus devices. Alternatives are on
14330 Defaults to @samp{"on"}.
14334 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
14335 Same as @code{runtime-pm-ac} but on BAT mode.
14337 Defaults to @samp{"auto"}.
14341 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
14342 Runtime Power Management for all PCI(e) bus devices, except blacklisted
14345 Defaults to @samp{#t}.
14349 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
14350 Exclude specified PCI(e) device addresses from Runtime Power Management.
14352 Defaults to @samp{disabled}.
14356 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
14357 Exclude PCI(e) devices assigned to the specified drivers from Runtime
14362 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
14363 Enable USB autosuspend feature.
14365 Defaults to @samp{#t}.
14369 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
14370 Exclude specified devices from USB autosuspend.
14372 Defaults to @samp{disabled}.
14376 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
14377 Exclude WWAN devices from USB autosuspend.
14379 Defaults to @samp{#t}.
14383 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
14384 Include specified devices into USB autosuspend, even if they are already
14385 excluded by the driver or via @code{usb-blacklist-wwan?}.
14387 Defaults to @samp{disabled}.
14391 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
14392 Enable USB autosuspend before shutdown.
14394 Defaults to @samp{disabled}.
14398 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
14399 Restore radio device state (bluetooth, wifi, wwan) from previous
14400 shutdown on system startup.
14402 Defaults to @samp{#f}.
14406 @node Miscellaneous Services
14407 @subsubsection Miscellaneous Services
14411 @subsubheading Lirc Service
14413 The @code{(gnu services lirc)} module provides the following service.
14415 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
14416 [#:device #f] [#:driver #f] [#:config-file #f] @
14417 [#:extra-options '()]
14418 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
14419 decodes infrared signals from remote controls.
14421 Optionally, @var{device}, @var{driver} and @var{config-file}
14422 (configuration file name) may be specified. See @command{lircd} manual
14425 Finally, @var{extra-options} is a list of additional command-line options
14426 passed to @command{lircd}.
14430 @subsubheading Spice Service
14432 The @code{(gnu services spice)} module provides the following service.
14434 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
14435 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
14436 that enables sharing the clipboard with a vm and setting the guest display
14437 resolution when the graphical console window resizes.
14440 @subsubsection Dictionary Services
14442 The @code{(gnu services dict)} module provides the following service:
14444 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
14445 Return a service that runs the @command{dicod} daemon, an implementation
14446 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
14448 The optional @var{config} argument specifies the configuration for
14449 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
14450 default it serves the GNU Collaborative International Dictonary of English.
14452 You can add @command{open localhost} to your @file{~/.dico} file to make
14453 @code{localhost} the default server for @command{dico} client
14454 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
14457 @deftp {Data Type} dicod-configuration
14458 Data type representing the configuration of dicod.
14461 @item @code{dico} (default: @var{dico})
14462 Package object of the GNU Dico dictionary server.
14464 @item @code{interfaces} (default: @var{'("localhost")})
14465 This is the list of IP addresses and ports and possibly socket file
14466 names to listen to (@pxref{Server Settings, @code{listen} directive,,
14467 dico, GNU Dico Manual}).
14469 @item @code{handlers} (default: @var{'()})
14470 List of @code{<dicod-handler>} objects denoting handlers (module instances).
14472 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
14473 List of @code{<dicod-database>} objects denoting dictionaries to be served.
14477 @deftp {Data Type} dicod-handler
14478 Data type representing a dictionary handler (module instance).
14482 Name of the handler (module instance).
14484 @item @code{module} (default: @var{#f})
14485 Name of the dicod module of the handler (instance). If it is @code{#f},
14486 the module has the same name as the handler.
14487 (@pxref{Modules,,, dico, GNU Dico Manual}).
14489 @item @code{options}
14490 List of strings or gexps representing the arguments for the module handler
14494 @deftp {Data Type} dicod-database
14495 Data type representing a dictionary database.
14499 Name of the database, will be used in DICT commands.
14501 @item @code{handler}
14502 Name of the dicod handler (module instance) used by this database
14503 (@pxref{Handlers,,, dico, GNU Dico Manual}).
14505 @item @code{complex?} (default: @var{#f})
14506 Whether the database configuration complex. The complex configuration
14507 will need a corresponding @code{<dicod-handler>} object, otherwise not.
14509 @item @code{options}
14510 List of strings or gexps representing the arguments for the database
14511 (@pxref{Databases,,, dico, GNU Dico Manual}).
14515 @defvr {Scheme Variable} %dicod-database:gcide
14516 A @code{<dicod-database>} object serving the GNU Collaborative International
14517 Dictionary of English using the @code{gcide} package.
14520 The following is an example @code{dicod-service} configuration.
14523 (dicod-service #:config
14524 (dicod-configuration
14525 (handlers (list (dicod-handler
14529 (list #~(string-append "dbdir=" #$wordnet))))))
14530 (databases (list (dicod-database
14533 (handler "wordnet")
14534 (options '("database=wn")))
14535 %dicod-database:gcide))))
14538 @subsubsection Version Control
14540 The @code{(gnu services version-control)} module provides the following services:
14542 @subsubheading Git daemon service
14544 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
14546 Return a service that runs @command{git daemon}, a simple TCP server to
14547 expose repositories over the Git protocol for anonymous access.
14549 The optional @var{config} argument should be a
14550 @code{<git-daemon-configuration>} object, by default it allows read-only
14551 access to exported@footnote{By creating the magic file
14552 "git-daemon-export-ok" in the repository directory.} repositories under
14557 @deftp {Data Type} git-daemon-configuration
14558 Data type representing the configuration for @code{git-daemon-service}.
14561 @item @code{package} (default: @var{git})
14562 Package object of the Git distributed version control system.
14564 @item @code{export-all?} (default: @var{#f})
14565 Whether to allow access for all Git repositories, even if they do not
14566 have the @file{git-daemon-export-ok} file.
14568 @item @code{base-path} (default: @file{/srv/git})
14569 Whether to remap all the path requests as relative to the given path.
14570 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
14571 then if you later try to pull @code{git://example.com/hello.git}, git
14572 daemon will interpret the path as @code{/srv/git/hello.git}.
14574 @item @code{user-path} (default: @var{#f})
14575 Whether to allow @code{~user} notation to be used in requests. When
14576 specified with empty string, requests to @code{git://host/~alice/foo} is
14577 taken as a request to access @code{foo} repository in the home directory
14578 of user @code{alice}. If @var{(user-path "path")} is specified, the
14579 same request is taken as a request to access @code{path/foo} repository
14580 in the home directory of user @code{alice}.
14582 @item @code{listen} (default: @var{'()})
14583 Whether to listen on specific IP addresses or hostnames, defaults to
14586 @item @code{port} (default: @var{#f})
14587 Whether to listen on an alternative port, which defaults to 9418.
14589 @item @code{whitelist} (default: @var{'()})
14590 If not empty, only allow access to this list of directories.
14592 @item @code{extra-options} (default: @var{'()})
14593 Extra options will be passed to @code{git daemon}, please run
14594 @command{man git-daemon} for more information.
14599 @node Setuid Programs
14600 @subsection Setuid Programs
14602 @cindex setuid programs
14603 Some programs need to run with ``root'' privileges, even when they are
14604 launched by unprivileged users. A notorious example is the
14605 @command{passwd} program, which users can run to change their
14606 password, and which needs to access the @file{/etc/passwd} and
14607 @file{/etc/shadow} files---something normally restricted to root, for
14608 obvious security reasons. To address that, these executables are
14609 @dfn{setuid-root}, meaning that they always run with root privileges
14610 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
14611 for more info about the setuid mechanism.)
14613 The store itself @emph{cannot} contain setuid programs: that would be a
14614 security issue since any user on the system can write derivations that
14615 populate the store (@pxref{The Store}). Thus, a different mechanism is
14616 used: instead of changing the setuid bit directly on files that are in
14617 the store, we let the system administrator @emph{declare} which programs
14618 should be setuid root.
14620 The @code{setuid-programs} field of an @code{operating-system}
14621 declaration contains a list of G-expressions denoting the names of
14622 programs to be setuid-root (@pxref{Using the Configuration System}).
14623 For instance, the @command{passwd} program, which is part of the Shadow
14624 package, can be designated by this G-expression (@pxref{G-Expressions}):
14627 #~(string-append #$shadow "/bin/passwd")
14630 A default set of setuid programs is defined by the
14631 @code{%setuid-programs} variable of the @code{(gnu system)} module.
14633 @defvr {Scheme Variable} %setuid-programs
14634 A list of G-expressions denoting common programs that are setuid-root.
14636 The list includes commands such as @command{passwd}, @command{ping},
14637 @command{su}, and @command{sudo}.
14640 Under the hood, the actual setuid programs are created in the
14641 @file{/run/setuid-programs} directory at system activation time. The
14642 files in this directory refer to the ``real'' binaries, which are in the
14645 @node X.509 Certificates
14646 @subsection X.509 Certificates
14648 @cindex HTTPS, certificates
14649 @cindex X.509 certificates
14651 Web servers available over HTTPS (that is, HTTP over the transport-layer
14652 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
14653 that the client can then use to @emph{authenticate} the server. To do
14654 that, clients verify that the server's certificate is signed by a
14655 so-called @dfn{certificate authority} (CA). But to verify the CA's
14656 signature, clients must have first acquired the CA's certificate.
14658 Web browsers such as GNU@tie{}IceCat include their own set of CA
14659 certificates, such that they are able to verify CA signatures
14662 However, most other programs that can talk HTTPS---@command{wget},
14663 @command{git}, @command{w3m}, etc.---need to be told where CA
14664 certificates can be found.
14666 @cindex @code{nss-certs}
14667 In GuixSD, this is done by adding a package that provides certificates
14668 to the @code{packages} field of the @code{operating-system} declaration
14669 (@pxref{operating-system Reference}). GuixSD includes one such package,
14670 @code{nss-certs}, which is a set of CA certificates provided as part of
14671 Mozilla's Network Security Services.
14673 Note that it is @emph{not} part of @var{%base-packages}, so you need to
14674 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
14675 most applications and libraries look for certificates by default, points
14676 to the certificates installed globally.
14678 Unprivileged users, including users of Guix on a foreign distro,
14679 can also install their own certificate package in
14680 their profile. A number of environment variables need to be defined so
14681 that applications and libraries know where to find them. Namely, the
14682 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
14683 variables. Some applications add their own environment variables; for
14684 instance, the Git version control system honors the certificate bundle
14685 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
14686 would typically run something like:
14689 $ guix package -i nss-certs
14690 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
14691 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
14692 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
14695 @node Name Service Switch
14696 @subsection Name Service Switch
14698 @cindex name service switch
14700 The @code{(gnu system nss)} module provides bindings to the
14701 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
14702 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
14703 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
14704 extended with new ``name'' lookup methods for system databases, which
14705 includes host names, service names, user accounts, and more (@pxref{Name
14706 Service Switch, System Databases and Name Service Switch,, libc, The GNU
14707 C Library Reference Manual}).
14709 The NSS configuration specifies, for each system database, which lookup
14710 method is to be used, and how the various methods are chained
14711 together---for instance, under which circumstances NSS should try the
14712 next method in the list. The NSS configuration is given in the
14713 @code{name-service-switch} field of @code{operating-system} declarations
14714 (@pxref{operating-system Reference, @code{name-service-switch}}).
14717 @cindex .local, host name lookup
14718 As an example, the declaration below configures the NSS to use the
14719 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
14720 back-end}, which supports host name lookups over multicast DNS (mDNS)
14721 for host names ending in @code{.local}:
14724 (name-service-switch
14725 (hosts (list %files ;first, check /etc/hosts
14727 ;; If the above did not succeed, try
14728 ;; with 'mdns_minimal'.
14730 (name "mdns_minimal")
14732 ;; 'mdns_minimal' is authoritative for
14733 ;; '.local'. When it returns "not found",
14734 ;; no need to try the next methods.
14735 (reaction (lookup-specification
14736 (not-found => return))))
14738 ;; Then fall back to DNS.
14742 ;; Finally, try with the "full" 'mdns'.
14747 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
14748 contains this configuration, so you will not have to type it if all you
14749 want is to have @code{.local} host lookup working.
14751 Note that, in this case, in addition to setting the
14752 @code{name-service-switch} of the @code{operating-system} declaration,
14753 you also need to use @code{avahi-service} (@pxref{Networking Services,
14754 @code{avahi-service}}), or @var{%desktop-services}, which includes it
14755 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
14756 to the name service cache daemon (@pxref{Base Services,
14757 @code{nscd-service}}).
14759 For convenience, the following variables provide typical NSS
14762 @defvr {Scheme Variable} %default-nss
14763 This is the default name service switch configuration, a
14764 @code{name-service-switch} object.
14767 @defvr {Scheme Variable} %mdns-host-lookup-nss
14768 This is the name service switch configuration with support for host name
14769 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
14772 The reference for name service switch configuration is given below. It
14773 is a direct mapping of the configuration file format of the C library , so
14774 please refer to the C library manual for more information (@pxref{NSS
14775 Configuration File,,, libc, The GNU C Library Reference Manual}).
14776 Compared to the configuration file format of libc NSS, it has the advantage
14777 not only of adding this warm parenthetic feel that we like, but also
14778 static checks: you will know about syntax errors and typos as soon as you
14779 run @command{guix system}.
14781 @deftp {Data Type} name-service-switch
14783 This is the data type representation the configuration of libc's name
14784 service switch (NSS). Each field below represents one of the supported
14801 The system databases handled by the NSS. Each of these fields must be a
14802 list of @code{<name-service>} objects (see below).
14806 @deftp {Data Type} name-service
14808 This is the data type representing an actual name service and the
14809 associated lookup action.
14813 A string denoting the name service (@pxref{Services in the NSS
14814 configuration,,, libc, The GNU C Library Reference Manual}).
14816 Note that name services listed here must be visible to nscd. This is
14817 achieved by passing the @code{#:name-services} argument to
14818 @code{nscd-service} the list of packages providing the needed name
14819 services (@pxref{Base Services, @code{nscd-service}}).
14822 An action specified using the @code{lookup-specification} macro
14823 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
14824 Reference Manual}). For example:
14827 (lookup-specification (unavailable => continue)
14828 (success => return))
14833 @node Initial RAM Disk
14834 @subsection Initial RAM Disk
14837 @cindex initial RAM disk
14838 For bootstrapping purposes, the Linux-Libre kernel is passed an
14839 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
14840 root file system as well as an initialization script. The latter is
14841 responsible for mounting the real root file system, and for loading any
14842 kernel modules that may be needed to achieve that.
14844 The @code{initrd} field of an @code{operating-system} declaration allows
14845 you to specify which initrd you would like to use. The @code{(gnu
14846 system linux-initrd)} module provides three ways to build an initrd: the
14847 high-level @code{base-initrd} procedure and the low-level
14848 @code{raw-initrd} and @code{expression->initrd} procedures.
14850 The @code{base-initrd} procedure is intended to cover most common uses.
14851 For example, if you want to add a bunch of kernel modules to be loaded
14852 at boot time, you can define the @code{initrd} field of the operating
14853 system declaration like this:
14856 (initrd (lambda (file-systems . rest)
14857 ;; Create a standard initrd that has modules "foo.ko"
14858 ;; and "bar.ko", as well as their dependencies, in
14859 ;; addition to the modules available by default.
14860 (apply base-initrd file-systems
14861 #:extra-modules '("foo" "bar")
14865 The @code{base-initrd} procedure also handles common use cases that
14866 involves using the system as a QEMU guest, or as a ``live'' system with
14867 volatile root file system.
14869 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
14870 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
14871 such as trying to guess which kernel modules and packages should be included
14872 to the initrd. An example use of @code{raw-initrd} is when a user has
14873 a custom Linux kernel configuration and default kernel modules included by
14874 @code{base-initrd} are not available.
14876 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
14877 honors several options passed on the Linux kernel command line
14878 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
14879 @code{-append} option of QEMU), notably:
14882 @item --load=@var{boot}
14883 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
14884 program, once it has mounted the root file system.
14886 GuixSD uses this option to yield control to a boot program that runs the
14887 service activation programs and then spawns the GNU@tie{}Shepherd, the
14888 initialization system.
14890 @item --root=@var{root}
14891 Mount @var{root} as the root file system. @var{root} can be a
14892 device name like @code{/dev/sda1}, a partition label, or a partition
14895 @item --system=@var{system}
14896 Have @file{/run/booted-system} and @file{/run/current-system} point to
14899 @item modprobe.blacklist=@var{modules}@dots{}
14900 @cindex module, black-listing
14901 @cindex black list, of kernel modules
14902 Instruct the initial RAM disk as well as the @command{modprobe} command
14903 (from the kmod package) to refuse to load @var{modules}. @var{modules}
14904 must be a comma-separated list of module names---e.g.,
14905 @code{usbkbd,9pnet}.
14908 Start a read-eval-print loop (REPL) from the initial RAM disk before it
14909 tries to load kernel modules and to mount the root file system. Our
14910 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
14911 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
14912 Manual}, for more information on Guile's REPL.
14916 Now that you know all the features that initial RAM disks produced by
14917 @code{base-initrd} and @code{raw-initrd} provide,
14918 here is how to use it and customize it further.
14921 @cindex initial RAM disk
14922 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
14923 [#:linux-modules '()] [#:mapped-devices '()] @
14924 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
14925 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
14926 a list of file systems to be mounted by the initrd, possibly in addition to
14927 the root file system specified on the kernel command line via @code{--root}.
14928 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
14929 @var{mapped-devices} is a list of device mappings to realize before
14930 @var{file-systems} are mounted (@pxref{Mapped Devices}).
14931 @var{helper-packages} is a list of packages to be copied in the initrd. It may
14932 include @code{e2fsck/static} or other packages needed by the initrd to check
14935 When @var{qemu-networking?} is true, set up networking with the standard QEMU
14936 parameters. When @var{virtio?} is true, load additional modules so that the
14937 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
14939 When @var{volatile-root?} is true, the root file system is writable but any changes
14943 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
14944 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
14945 [#:virtio? #t] [#:extra-modules '()]
14946 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
14947 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
14948 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
14949 also behaves as in @code{raw-initrd}.
14951 When @var{virtio?} is true, load additional modules so that the
14952 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
14954 The initrd is automatically populated with all the kernel modules necessary
14955 for @var{file-systems} and for the given options. However, additional kernel
14956 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
14957 loaded at boot time in the order in which they appear.
14960 Needless to say, the initrds we produce and use embed a
14961 statically-linked Guile, and the initialization program is a Guile
14962 program. That gives a lot of flexibility. The
14963 @code{expression->initrd} procedure builds such an initrd, given the
14964 program to run in that initrd.
14966 @deffn {Monadic Procedure} expression->initrd @var{exp} @
14967 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
14968 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
14969 containing @var{guile} and that evaluates @var{exp}, a G-expression,
14970 upon booting. All the derivations referenced by @var{exp} are
14971 automatically copied to the initrd.
14974 @node GRUB Configuration
14975 @subsection GRUB Configuration
14978 @cindex boot loader
14980 The operating system uses GNU@tie{}GRUB as its boot loader
14981 (@pxref{Overview, overview of GRUB,, grub, GNU GRUB Manual}). It is
14982 configured using a @code{grub-configuration} declaration. This data type
14983 is exported by the @code{(gnu system grub)} module and described below.
14985 @deftp {Data Type} grub-configuration
14986 The type of a GRUB configuration declaration.
14990 @item @code{device}
14991 This is a string denoting the boot device. It must be a device name
14992 understood by the @command{grub-install} command, such as
14993 @code{/dev/sda} or @code{(hd0)} (@pxref{Invoking grub-install,,, grub,
14996 @item @code{menu-entries} (default: @code{()})
14997 A possibly empty list of @code{menu-entry} objects (see below), denoting
14998 entries to appear in the GRUB boot menu, in addition to the current
14999 system entry and the entry pointing to previous system generations.
15001 @item @code{default-entry} (default: @code{0})
15002 The index of the default boot menu entry. Index 0 is for the entry of the
15005 @item @code{timeout} (default: @code{5})
15006 The number of seconds to wait for keyboard input before booting. Set to
15007 0 to boot immediately, and to -1 to wait indefinitely.
15009 @item @code{theme} (default: @var{%default-theme})
15010 The @code{grub-theme} object describing the theme to use.
15012 @item @code{grub} (default: @code{grub})
15013 The GRUB package to use.
15020 Should you want to list additional boot menu entries @i{via} the
15021 @code{menu-entries} field above, you will need to create them with the
15022 @code{menu-entry} form. For example, imagine you want to be able to
15023 boot another distro (hard to imagine!), you can define a menu entry
15028 (label "The Other Distro")
15029 (linux "/boot/old/vmlinux-2.6.32")
15030 (linux-arguments '("root=/dev/sda2"))
15031 (initrd "/boot/old/initrd"))
15036 @deftp {Data Type} menu-entry
15037 The type of an entry in the GRUB boot menu.
15042 The label to show in the menu---e.g., @code{"GNU"}.
15045 The Linux kernel image to boot, for example:
15048 (file-append linux-libre "/bzImage")
15051 It is also possible to specify a device explicitly in the file path
15052 using GRUB's device naming convention (@pxref{Naming convention,,, grub,
15053 GNU GRUB manual}), for example:
15056 "(hd0,msdos1)/boot/vmlinuz"
15059 If the device is specified explicitly as above, then the @code{device}
15060 field is ignored entirely.
15062 @item @code{linux-arguments} (default: @code{()})
15063 The list of extra Linux kernel command-line arguments---e.g.,
15064 @code{("console=ttyS0")}.
15066 @item @code{initrd}
15067 A G-Expression or string denoting the file name of the initial RAM disk
15068 to use (@pxref{G-Expressions}).
15070 @item @code{device} (default: @code{#f})
15071 The device where the kernel and initrd are to be found---i.e., the GRUB
15072 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
15074 This may be a file system label (a string), a file system UUID (a
15075 bytevector, @pxref{File Systems}), or @code{#f}, in which case GRUB will
15076 search the device containing the file specified by the @code{linux}
15077 field (@pxref{search,,, grub, GNU GRUB manual}). It must @emph{not} be
15078 an OS device name such as @file{/dev/sda1}.
15080 @item @code{device-mount-point} (default: @code{"/"})
15081 The mount point of the above device on the system. You probably do not
15082 need to change the default value. GuixSD uses it to strip the prefix of
15083 store file names for systems where @file{/gnu} or @file{/gnu/store} is
15084 on a separate partition.
15089 @c FIXME: Write documentation once it's stable.
15090 Themes are created using the @code{grub-theme} form, which is not
15093 @defvr {Scheme Variable} %default-theme
15094 This is the default GRUB theme used by the operating system, with a
15095 fancy background image displaying the GNU and Guix logos.
15099 @node Invoking guix system
15100 @subsection Invoking @code{guix system}
15102 Once you have written an operating system declaration as seen in the
15103 previous section, it can be @dfn{instantiated} using the @command{guix
15104 system} command. The synopsis is:
15107 guix system @var{options}@dots{} @var{action} @var{file}
15110 @var{file} must be the name of a file containing an
15111 @code{operating-system} declaration. @var{action} specifies how the
15112 operating system is instantiated. Currently the following values are
15117 Build the operating system described in @var{file}, activate it, and
15118 switch to it@footnote{This action (and the related actions
15119 @code{switch-generation} and @code{roll-back}) are usable only on
15120 systems already running GuixSD.}.
15122 This effects all the configuration specified in @var{file}: user
15123 accounts, system services, global package list, setuid programs, etc.
15124 The command starts system services specified in @var{file} that are not
15125 currently running; if a service is currently running, it does not
15126 attempt to upgrade it since this would not be possible without stopping it
15129 This command creates a new generation whose number is one greater than
15130 the current generation (as reported by @command{guix system
15131 list-generations}). If that generation already exists, it will be
15132 overwritten. This behavior mirrors that of @command{guix package}
15133 (@pxref{Invoking guix package}).
15135 It also adds a GRUB menu entry for the new OS configuration, and moves
15136 entries for older configurations to a submenu---unless
15137 @option{--no-bootloader} is passed.
15140 @c The paragraph below refers to the problem discussed at
15141 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
15142 It is highly recommended to run @command{guix pull} once before you run
15143 @command{guix system reconfigure} for the first time (@pxref{Invoking
15144 guix pull}). Failing to do that you would see an older version of Guix
15145 once @command{reconfigure} has completed.
15148 @item switch-generation
15149 @cindex generations
15150 Switch to an existing system generation. This action atomically
15151 switches the system profile to the specified system generation. It also
15152 rearranges the system's existing GRUB menu entries. It makes the menu
15153 entry for the specified system generation the default, and it moves the
15154 entries for the other generations to a submenu. The next time the
15155 system boots, it will use the specified system generation.
15157 The target generation can be specified explicitly by its generation
15158 number. For example, the following invocation would switch to system
15162 guix system switch-generation 7
15165 The target generation can also be specified relative to the current
15166 generation with the form @code{+N} or @code{-N}, where @code{+3} means
15167 ``3 generations ahead of the current generation,'' and @code{-1} means
15168 ``1 generation prior to the current generation.'' When specifying a
15169 negative value such as @code{-1}, you must precede it with @code{--} to
15170 prevent it from being parsed as an option. For example:
15173 guix system switch-generation -- -1
15176 Currently, the effect of invoking this action is @emph{only} to switch
15177 the system profile to an existing generation and rearrange the GRUB menu
15178 entries. To actually start using the target system generation, you must
15179 reboot after running this action. In the future, it will be updated to
15180 do the same things as @command{reconfigure}, like activating and
15181 deactivating services.
15183 This action will fail if the specified generation does not exist.
15186 @cindex rolling back
15187 Switch to the preceding system generation. The next time the system
15188 boots, it will use the preceding system generation. This is the inverse
15189 of @command{reconfigure}, and it is exactly the same as invoking
15190 @command{switch-generation} with an argument of @code{-1}.
15192 Currently, as with @command{switch-generation}, you must reboot after
15193 running this action to actually start using the preceding system
15197 Build the derivation of the operating system, which includes all the
15198 configuration files and programs needed to boot and run the system.
15199 This action does not actually install anything.
15202 Populate the given directory with all the files necessary to run the
15203 operating system specified in @var{file}. This is useful for first-time
15204 installations of GuixSD. For instance:
15207 guix system init my-os-config.scm /mnt
15210 copies to @file{/mnt} all the store items required by the configuration
15211 specified in @file{my-os-config.scm}. This includes configuration
15212 files, packages, and so on. It also creates other essential files
15213 needed for the system to operate correctly---e.g., the @file{/etc},
15214 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
15216 This command also installs GRUB on the device specified in
15217 @file{my-os-config}, unless the @option{--no-bootloader} option was passed.
15220 @cindex virtual machine
15222 @anchor{guix system vm}
15223 Build a virtual machine that contains the operating system declared in
15224 @var{file}, and return a script to run that virtual machine (VM).
15225 Arguments given to the script are passed to QEMU.
15227 The VM shares its store with the host system.
15229 Additional file systems can be shared between the host and the VM using
15230 the @code{--share} and @code{--expose} command-line options: the former
15231 specifies a directory to be shared with write access, while the latter
15232 provides read-only access to the shared directory.
15234 The example below creates a VM in which the user's home directory is
15235 accessible read-only, and where the @file{/exchange} directory is a
15236 read-write mapping of @file{$HOME/tmp} on the host:
15239 guix system vm my-config.scm \
15240 --expose=$HOME --share=$HOME/tmp=/exchange
15243 On GNU/Linux, the default is to boot directly to the kernel; this has
15244 the advantage of requiring only a very tiny root disk image since the
15245 store of the host can then be mounted.
15247 The @code{--full-boot} option forces a complete boot sequence, starting
15248 with the bootloader. This requires more disk space since a root image
15249 containing at least the kernel, initrd, and bootloader data files must
15250 be created. The @code{--image-size} option can be used to specify the
15255 Return a virtual machine or disk image of the operating system declared
15256 in @var{file} that stands alone. Use the @option{--image-size} option
15257 to specify the size of the image.
15259 When using @code{vm-image}, the returned image is in qcow2 format, which
15260 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
15261 for more information on how to run the image in a virtual machine.
15263 When using @code{disk-image}, a raw disk image is produced; it can be
15264 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
15265 the device corresponding to a USB stick, one can copy the image to it
15266 using the following command:
15269 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
15273 Return a script to run the operating system declared in @var{file}
15274 within a container. Containers are a set of lightweight isolation
15275 mechanisms provided by the kernel Linux-libre. Containers are
15276 substantially less resource-demanding than full virtual machines since
15277 the kernel, shared objects, and other resources can be shared with the
15278 host system; this also means they provide thinner isolation.
15280 Currently, the script must be run as root in order to support more than
15281 a single user and group. The container shares its store with the host
15284 As with the @code{vm} action (@pxref{guix system vm}), additional file
15285 systems to be shared between the host and container can be specified
15286 using the @option{--share} and @option{--expose} options:
15289 guix system container my-config.scm \
15290 --expose=$HOME --share=$HOME/tmp=/exchange
15294 This option requires Linux-libre 3.19 or newer.
15299 @var{options} can contain any of the common build options (@pxref{Common
15300 Build Options}). In addition, @var{options} can contain one of the
15304 @item --system=@var{system}
15305 @itemx -s @var{system}
15306 Attempt to build for @var{system} instead of the host system type.
15307 This works as per @command{guix build} (@pxref{Invoking guix build}).
15311 Return the derivation file name of the given operating system without
15314 @item --image-size=@var{size}
15315 For the @code{vm-image} and @code{disk-image} actions, create an image
15316 of the given @var{size}. @var{size} may be a number of bytes, or it may
15317 include a unit as a suffix (@pxref{Block size, size specifications,,
15318 coreutils, GNU Coreutils}).
15320 @item --root=@var{file}
15321 @itemx -r @var{file}
15322 Make @var{file} a symlink to the result, and register it as a garbage
15325 @item --on-error=@var{strategy}
15326 Apply @var{strategy} when an error occurs when reading @var{file}.
15327 @var{strategy} may be one of the following:
15330 @item nothing-special
15331 Report the error concisely and exit. This is the default strategy.
15334 Likewise, but also display a backtrace.
15337 Report the error and enter Guile's debugger. From there, you can run
15338 commands such as @code{,bt} to get a backtrace, @code{,locals} to
15339 display local variable values, and more generally inspect the state of the
15340 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
15341 a list of available debugging commands.
15346 All the actions above, except @code{build} and @code{init},
15347 can use KVM support in the Linux-libre kernel. Specifically, if the
15348 machine has hardware virtualization support, the corresponding
15349 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
15350 must exist and be readable and writable by the user and by the
15351 build users of the daemon (@pxref{Build Environment Setup}).
15354 Once you have built, configured, re-configured, and re-re-configured
15355 your GuixSD installation, you may find it useful to list the operating
15356 system generations available on disk---and that you can choose from the
15361 @item list-generations
15362 List a summary of each generation of the operating system available on
15363 disk, in a human-readable way. This is similar to the
15364 @option{--list-generations} option of @command{guix package}
15365 (@pxref{Invoking guix package}).
15367 Optionally, one can specify a pattern, with the same syntax that is used
15368 in @command{guix package --list-generations}, to restrict the list of
15369 generations displayed. For instance, the following command displays
15370 generations that are up to 10 days old:
15373 $ guix system list-generations 10d
15378 The @command{guix system} command has even more to offer! The following
15379 sub-commands allow you to visualize how your system services relate to
15382 @anchor{system-extension-graph}
15385 @item extension-graph
15386 Emit in Dot/Graphviz format to standard output the @dfn{service
15387 extension graph} of the operating system defined in @var{file}
15388 (@pxref{Service Composition}, for more information on service
15394 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
15397 produces a PDF file showing the extension relations among services.
15399 @anchor{system-shepherd-graph}
15400 @item shepherd-graph
15401 Emit in Dot/Graphviz format to standard output the @dfn{dependency
15402 graph} of shepherd services of the operating system defined in
15403 @var{file}. @xref{Shepherd Services}, for more information and for an
15408 @node Running GuixSD in a VM
15409 @subsection Running GuixSD in a Virtual Machine
15411 @cindex virtual machine
15412 One way to run GuixSD in a virtual machine (VM) is to build a GuixSD
15413 virtual machine image using @command{guix system vm-image}
15414 (@pxref{Invoking guix system}). The returned image is in qcow2 format,
15415 which the @uref{http://qemu.org/, QEMU emulator} can efficiently use.
15418 To run the image in QEMU, copy it out of the store (@pxref{The Store})
15419 and give yourself permission to write to the copy. When invoking QEMU,
15420 you must choose a system emulator that is suitable for your hardware
15421 platform. Here is a minimal QEMU invocation that will boot the result
15422 of @command{guix system vm-image} on x86_64 hardware:
15425 $ qemu-system-x86_64 \
15426 -net user -net nic,model=virtio \
15427 -enable-kvm -m 256 /tmp/qemu-image
15430 Here is what each of these options means:
15433 @item qemu-system-x86_64
15434 This specifies the hardware platform to emulate. This should match the
15438 Enable the unprivileged user-mode network stack. The guest OS can
15439 access the host but not vice versa. This is the simplest way to get the
15442 @item -net nic,model=virtio
15443 You must create a network interface of a given model. If you do not
15444 create a NIC, the boot will fail. Assuming your hardware platform is
15445 x86_64, you can get a list of available NIC models by running
15446 @command{qemu-system-x86_64 -net nic,model=help}.
15449 If your system has hardware virtualization extensions, enabling the
15450 virtual machine support (KVM) of the Linux kernel will make things run
15454 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
15455 which may be insufficient for some operations.
15457 @item /tmp/qemu-image
15458 The file name of the qcow2 image.
15461 The default @command{run-vm.sh} script that is returned by an invocation of
15462 @command{guix system vm} does not add a @command{-net user} flag by default.
15463 To get network access from within the vm add the @code{(dhcp-client-service)}
15464 to your system definition and start the VM using
15465 @command{`guix system vm config.scm` -net user}. An important caveat of using
15466 @command{-net user} for networking is that @command{ping} will not work, because
15467 it uses the ICMP protocol. You'll have to use a different command to check for
15468 network connectivity, like for example @command{curl}.
15470 @subsubsection Connecting Through SSH
15474 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
15475 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
15476 boot unsupervised. It requires you to type some characters to initialize the
15477 randomness generator. In addition you need to forward the SSH port, 22 by
15478 default, to the host. You can do this with
15481 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
15484 To connect to the VM you can run
15487 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
15490 The @command{-p} tells @command{ssh} the port you want to connect to.
15491 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
15492 every time you modify your @command{config.scm} file and the
15493 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
15494 connection to an unknown host every time you connect.
15496 @subsubsection Using @command{virt-viewer} with Spice
15498 As an alternative to the default @command{qemu} graphical client you can
15499 use the @command{remote-viewer} from the @command{virt-viewer} package. To
15500 connect pass the @command{-spice port=5930,disable-ticketing} flag to
15501 @command{qemu}. See previous section for further information on how to do this.
15503 Spice also allows you to do some nice stuff like share your clipboard with your
15504 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
15507 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
15508 -chardev spicevmc,name=vdagent,id=vdagent
15509 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
15510 name=com.redhat.spice.0
15513 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
15515 @node Defining Services
15516 @subsection Defining Services
15518 The previous sections show the available services and how one can combine
15519 them in an @code{operating-system} declaration. But how do we define
15520 them in the first place? And what is a service anyway?
15523 * Service Composition:: The model for composing services.
15524 * Service Types and Services:: Types and services.
15525 * Service Reference:: API reference.
15526 * Shepherd Services:: A particular type of service.
15529 @node Service Composition
15530 @subsubsection Service Composition
15534 Here we define a @dfn{service} as, broadly, something that extends the
15535 functionality of the operating system. Often a service is a process---a
15536 @dfn{daemon}---started when the system boots: a secure shell server, a
15537 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
15538 whose execution can be triggered by another daemon---e.g., an FTP server
15539 started by @command{inetd} or a D-Bus service activated by
15540 @command{dbus-daemon}. Occasionally, a service does not map to a
15541 daemon. For instance, the ``account'' service collects user accounts
15542 and makes sure they exist when the system runs; the ``udev'' service
15543 collects device management rules and makes them available to the eudev
15544 daemon; the @file{/etc} service populates the @file{/etc} directory
15547 @cindex service extensions
15548 GuixSD services are connected by @dfn{extensions}. For instance, the
15549 secure shell service @emph{extends} the Shepherd---the GuixSD
15550 initialization system, running as PID@tie{}1---by giving it the command
15551 lines to start and stop the secure shell daemon (@pxref{Networking
15552 Services, @code{lsh-service}}); the UPower service extends the D-Bus
15553 service by passing it its @file{.service} specification, and extends the
15554 udev service by passing it device management rules (@pxref{Desktop
15555 Services, @code{upower-service}}); the Guix daemon service extends the
15556 Shepherd by passing it the command lines to start and stop the daemon,
15557 and extends the account service by passing it a list of required build
15558 user accounts (@pxref{Base Services}).
15560 All in all, services and their ``extends'' relations form a directed
15561 acyclic graph (DAG). If we represent services as boxes and extensions
15562 as arrows, a typical system might provide something like this:
15564 @image{images/service-graph,,5in,Typical service extension graph.}
15566 @cindex system service
15567 At the bottom, we see the @dfn{system service}, which produces the
15568 directory containing everything to run and boot the system, as returned
15569 by the @command{guix system build} command. @xref{Service Reference},
15570 to learn about the other service types shown here.
15571 @xref{system-extension-graph, the @command{guix system extension-graph}
15572 command}, for information on how to generate this representation for a
15573 particular operating system definition.
15575 @cindex service types
15576 Technically, developers can define @dfn{service types} to express these
15577 relations. There can be any number of services of a given type on the
15578 system---for instance, a system running two instances of the GNU secure
15579 shell server (lsh) has two instances of @var{lsh-service-type}, with
15580 different parameters.
15582 The following section describes the programming interface for service
15583 types and services.
15585 @node Service Types and Services
15586 @subsubsection Service Types and Services
15588 A @dfn{service type} is a node in the DAG described above. Let us start
15589 with a simple example, the service type for the Guix build daemon
15590 (@pxref{Invoking guix-daemon}):
15593 (define guix-service-type
15597 (list (service-extension shepherd-root-service-type guix-shepherd-service)
15598 (service-extension account-service-type guix-accounts)
15599 (service-extension activation-service-type guix-activation)))
15600 (default-value (guix-configuration))))
15604 It defines three things:
15608 A name, whose sole purpose is to make inspection and debugging easier.
15611 A list of @dfn{service extensions}, where each extension designates the
15612 target service type and a procedure that, given the parameters of the
15613 service, returns a list of objects to extend the service of that type.
15615 Every service type has at least one service extension. The only
15616 exception is the @dfn{boot service type}, which is the ultimate service.
15619 Optionally, a default value for instances of this type.
15622 In this example, @var{guix-service-type} extends three services:
15625 @item shepherd-root-service-type
15626 The @var{guix-shepherd-service} procedure defines how the Shepherd
15627 service is extended. Namely, it returns a @code{<shepherd-service>}
15628 object that defines how @command{guix-daemon} is started and stopped
15629 (@pxref{Shepherd Services}).
15631 @item account-service-type
15632 This extension for this service is computed by @var{guix-accounts},
15633 which returns a list of @code{user-group} and @code{user-account}
15634 objects representing the build user accounts (@pxref{Invoking
15637 @item activation-service-type
15638 Here @var{guix-activation} is a procedure that returns a gexp, which is
15639 a code snippet to run at ``activation time''---e.g., when the service is
15643 A service of this type is instantiated like this:
15646 (service guix-service-type
15647 (guix-configuration
15649 (use-substitutes? #f)))
15652 The second argument to the @code{service} form is a value representing
15653 the parameters of this specific service instance.
15654 @xref{guix-configuration-type, @code{guix-configuration}}, for
15655 information about the @code{guix-configuration} data type. When the
15656 value is omitted, the default value specified by
15657 @code{guix-service-type} is used:
15660 (service guix-service-type)
15663 @var{guix-service-type} is quite simple because it extends other
15664 services but is not extensible itself.
15666 @c @subsubsubsection Extensible Service Types
15668 The service type for an @emph{extensible} service looks like this:
15671 (define udev-service-type
15672 (service-type (name 'udev)
15674 (list (service-extension shepherd-root-service-type
15675 udev-shepherd-service)))
15677 (compose concatenate) ;concatenate the list of rules
15678 (extend (lambda (config rules)
15680 (($ <udev-configuration> udev initial-rules)
15681 (udev-configuration
15682 (udev udev) ;the udev package to use
15683 (rules (append initial-rules rules)))))))))
15686 This is the service type for the
15687 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
15688 management daemon}. Compared to the previous example, in addition to an
15689 extension of @var{shepherd-root-service-type}, we see two new fields:
15693 This is the procedure to @dfn{compose} the list of extensions to
15694 services of this type.
15696 Services can extend the udev service by passing it lists of rules; we
15697 compose those extensions simply by concatenating them.
15700 This procedure defines how the value of the service is @dfn{extended} with
15701 the composition of the extensions.
15703 Udev extensions are composed into a list of rules, but the udev service
15704 value is itself a @code{<udev-configuration>} record. So here, we
15705 extend that record by appending the list of rules it contains to the
15706 list of contributed rules.
15709 There can be only one instance of an extensible service type such as
15710 @var{udev-service-type}. If there were more, the
15711 @code{service-extension} specifications would be ambiguous.
15713 Still here? The next section provides a reference of the programming
15714 interface for services.
15716 @node Service Reference
15717 @subsubsection Service Reference
15719 We have seen an overview of service types (@pxref{Service Types and
15720 Services}). This section provides a reference on how to manipulate
15721 services and service types. This interface is provided by the
15722 @code{(gnu services)} module.
15724 @deffn {Scheme Procedure} service @var{type} [@var{value}]
15725 Return a new service of @var{type}, a @code{<service-type>} object (see
15726 below.) @var{value} can be any object; it represents the parameters of
15727 this particular service instance.
15729 When @var{value} is omitted, the default value specified by @var{type}
15730 is used; if @var{type} does not specify a default value, an error is
15733 For instance, this:
15736 (service openssh-service-type)
15740 is equivalent to this:
15743 (service openssh-service-type
15744 (openssh-configuration))
15747 In both cases the result is an instance of @code{openssh-service-type}
15748 with the default configuration.
15751 @deffn {Scheme Procedure} service? @var{obj}
15752 Return true if @var{obj} is a service.
15755 @deffn {Scheme Procedure} service-kind @var{service}
15756 Return the type of @var{service}---i.e., a @code{<service-type>} object.
15759 @deffn {Scheme Procedure} service-value @var{service}
15760 Return the value associated with @var{service}. It represents its
15764 Here is an example of how a service is created and manipulated:
15768 (service nginx-service-type
15769 (nginx-configuration
15771 (log-directory log-directory)
15772 (run-directory run-directory)
15773 (file config-file))))
15778 (eq? (service-kind s) nginx-service-type)
15782 The @code{modify-services} form provides a handy way to change the
15783 parameters of some of the services of a list such as
15784 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
15785 evaluates to a list of services. Of course, you could always use
15786 standard list combinators such as @code{map} and @code{fold} to do that
15787 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
15788 @code{modify-services} simply provides a more concise form for this
15791 @deffn {Scheme Syntax} modify-services @var{services} @
15792 (@var{type} @var{variable} => @var{body}) @dots{}
15794 Modify the services listed in @var{services} according to the given
15795 clauses. Each clause has the form:
15798 (@var{type} @var{variable} => @var{body})
15801 where @var{type} is a service type---e.g.,
15802 @code{guix-service-type}---and @var{variable} is an identifier that is
15803 bound within the @var{body} to the service parameters---e.g., a
15804 @code{guix-configuration} instance---of the original service of that
15807 The @var{body} should evaluate to the new service parameters, which will
15808 be used to configure the new service. This new service will replace the
15809 original in the resulting list. Because a service's service parameters
15810 are created using @code{define-record-type*}, you can write a succinct
15811 @var{body} that evaluates to the new service parameters by using the
15812 @code{inherit} feature that @code{define-record-type*} provides.
15814 @xref{Using the Configuration System}, for example usage.
15818 Next comes the programming interface for service types. This is
15819 something you want to know when writing new service definitions, but not
15820 necessarily when simply looking for ways to customize your
15821 @code{operating-system} declaration.
15823 @deftp {Data Type} service-type
15824 @cindex service type
15825 This is the representation of a @dfn{service type} (@pxref{Service Types
15830 This is a symbol, used only to simplify inspection and debugging.
15832 @item @code{extensions}
15833 A non-empty list of @code{<service-extension>} objects (see below).
15835 @item @code{compose} (default: @code{#f})
15836 If this is @code{#f}, then the service type denotes services that cannot
15837 be extended---i.e., services that do not receive ``values'' from other
15840 Otherwise, it must be a one-argument procedure. The procedure is called
15841 by @code{fold-services} and is passed a list of values collected from
15842 extensions. It must return a value that is a valid parameter value for
15843 the service instance.
15845 @item @code{extend} (default: @code{#f})
15846 If this is @code{#f}, services of this type cannot be extended.
15848 Otherwise, it must be a two-argument procedure: @code{fold-services}
15849 calls it, passing it the initial value of the service as the first argument
15850 and the result of applying @code{compose} to the extension values as the
15854 @xref{Service Types and Services}, for examples.
15857 @deffn {Scheme Procedure} service-extension @var{target-type} @
15859 Return a new extension for services of type @var{target-type}.
15860 @var{compute} must be a one-argument procedure: @code{fold-services}
15861 calls it, passing it the value associated with the service that provides
15862 the extension; it must return a valid value for the target service.
15865 @deffn {Scheme Procedure} service-extension? @var{obj}
15866 Return true if @var{obj} is a service extension.
15869 Occasionally, you might want to simply extend an existing service. This
15870 involves creating a new service type and specifying the extension of
15871 interest, which can be verbose; the @code{simple-service} procedure
15872 provides a shorthand for this.
15874 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
15875 Return a service that extends @var{target} with @var{value}. This works
15876 by creating a singleton service type @var{name}, of which the returned
15877 service is an instance.
15879 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
15883 (simple-service 'my-mcron-job mcron-service-type
15884 #~(job '(next-hour (3)) "guix gc -F 2G"))
15888 At the core of the service abstraction lies the @code{fold-services}
15889 procedure, which is responsible for ``compiling'' a list of services
15890 down to a single directory that contains everything needed to boot and
15891 run the system---the directory shown by the @command{guix system build}
15892 command (@pxref{Invoking guix system}). In essence, it propagates
15893 service extensions down the service graph, updating each node parameters
15894 on the way, until it reaches the root node.
15896 @deffn {Scheme Procedure} fold-services @var{services} @
15897 [#:target-type @var{system-service-type}]
15898 Fold @var{services} by propagating their extensions down to the root of
15899 type @var{target-type}; return the root service adjusted accordingly.
15902 Lastly, the @code{(gnu services)} module also defines several essential
15903 service types, some of which are listed below.
15905 @defvr {Scheme Variable} system-service-type
15906 This is the root of the service graph. It produces the system directory
15907 as returned by the @command{guix system build} command.
15910 @defvr {Scheme Variable} boot-service-type
15911 The type of the ``boot service'', which produces the @dfn{boot script}.
15912 The boot script is what the initial RAM disk runs when booting.
15915 @defvr {Scheme Variable} etc-service-type
15916 The type of the @file{/etc} service. This service can be extended by
15917 passing it name/file tuples such as:
15920 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
15923 In this example, the effect would be to add an @file{/etc/issue} file
15924 pointing to the given file.
15927 @defvr {Scheme Variable} setuid-program-service-type
15928 Type for the ``setuid-program service''. This service collects lists of
15929 executable file names, passed as gexps, and adds them to the set of
15930 setuid-root programs on the system (@pxref{Setuid Programs}).
15933 @defvr {Scheme Variable} profile-service-type
15934 Type of the service that populates the @dfn{system profile}---i.e., the
15935 programs under @file{/run/current-system/profile}. Other services can
15936 extend it by passing it lists of packages to add to the system profile.
15940 @node Shepherd Services
15941 @subsubsection Shepherd Services
15943 @cindex shepherd services
15945 @cindex init system
15946 The @code{(gnu services shepherd)} module provides a way to define
15947 services managed by the GNU@tie{}Shepherd, which is the GuixSD
15948 initialization system---the first process that is started when the
15949 system boots, also known as PID@tie{}1
15950 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
15952 Services in the Shepherd can depend on each other. For instance, the
15953 SSH daemon may need to be started after the syslog daemon has been
15954 started, which in turn can only happen once all the file systems have
15955 been mounted. The simple operating system defined earlier (@pxref{Using
15956 the Configuration System}) results in a service graph like this:
15958 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
15960 You can actually generate such a graph for any operating system
15961 definition using the @command{guix system shepherd-graph} command
15962 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
15964 The @var{%shepherd-root-service} is a service object representing
15965 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
15966 by passing it lists of @code{<shepherd-service>} objects.
15968 @deftp {Data Type} shepherd-service
15969 The data type representing a service managed by the Shepherd.
15972 @item @code{provision}
15973 This is a list of symbols denoting what the service provides.
15975 These are the names that may be passed to @command{herd start},
15976 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
15977 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
15978 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
15980 @item @code{requirements} (default: @code{'()})
15981 List of symbols denoting the Shepherd services this one depends on.
15983 @item @code{respawn?} (default: @code{#t})
15984 Whether to restart the service when it stops, for instance when the
15985 underlying process dies.
15988 @itemx @code{stop} (default: @code{#~(const #f)})
15989 The @code{start} and @code{stop} fields refer to the Shepherd's
15990 facilities to start and stop processes (@pxref{Service De- and
15991 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
15992 G-expressions that get expanded in the Shepherd configuration file
15993 (@pxref{G-Expressions}).
15995 @item @code{documentation}
15996 A documentation string, as shown when running:
15999 herd doc @var{service-name}
16002 where @var{service-name} is one of the symbols in @var{provision}
16003 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
16005 @item @code{modules} (default: @var{%default-modules})
16006 This is the list of modules that must be in scope when @code{start} and
16007 @code{stop} are evaluated.
16012 @defvr {Scheme Variable} shepherd-root-service-type
16013 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
16015 This is the service type that extensions target when they want to create
16016 shepherd services (@pxref{Service Types and Services}, for an example).
16017 Each extension must pass a list of @code{<shepherd-service>}.
16020 @defvr {Scheme Variable} %shepherd-root-service
16021 This service represents PID@tie{}1.
16025 @node Documentation
16026 @section Documentation
16028 @cindex documentation, searching for
16029 @cindex searching for documentation
16030 @cindex Info, documentation format
16032 @cindex manual pages
16033 In most cases packages installed with Guix come with documentation.
16034 There are two main documentation formats: ``Info'', a browseable
16035 hypertext format used for GNU software, and ``manual pages'' (or ``man
16036 pages''), the linear documentation format traditionally found on Unix.
16037 Info manuals are accessed with the @command{info} command or with Emacs,
16038 and man pages are accessed using @command{man}.
16040 You can look for documentation of software installed on your system by
16041 keyword. For example, the following command searches for information
16042 about ``TLS'' in Info manuals:
16046 "(emacs)Network Security" -- STARTTLS
16047 "(emacs)Network Security" -- TLS
16048 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
16049 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
16054 The command below searches for the same keyword in man pages:
16058 SSL (7) - OpenSSL SSL/TLS library
16059 certtool (1) - GnuTLS certificate tool
16063 These searches are purely local to your computer so you have the
16064 guarantee that documentation you find corresponds to what you have
16065 actually installed, you can access it off-line, and your privacy is
16068 Once you have these results, you can view the relevant documentation by
16072 $ info "(gnutls)Core TLS API"
16082 Info manuals contain sections and indices as well as hyperlinks like
16083 those found in Web pages. The @command{info} reader (@pxref{Top, Info
16084 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
16085 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
16086 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
16087 Introduction}, for an introduction to Info navigation.
16089 @node Installing Debugging Files
16090 @section Installing Debugging Files
16092 @cindex debugging files
16093 Program binaries, as produced by the GCC compilers for instance, are
16094 typically written in the ELF format, with a section containing
16095 @dfn{debugging information}. Debugging information is what allows the
16096 debugger, GDB, to map binary code to source code; it is required to
16097 debug a compiled program in good conditions.
16099 The problem with debugging information is that is takes up a fair amount
16100 of disk space. For example, debugging information for the GNU C Library
16101 weighs in at more than 60 MiB. Thus, as a user, keeping all the
16102 debugging info of all the installed programs is usually not an option.
16103 Yet, space savings should not come at the cost of an impediment to
16104 debugging---especially in the GNU system, which should make it easier
16105 for users to exert their computing freedom (@pxref{GNU Distribution}).
16107 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
16108 mechanism that allows users to get the best of both worlds: debugging
16109 information can be stripped from the binaries and stored in separate
16110 files. GDB is then able to load debugging information from those files,
16111 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
16114 The GNU distribution takes advantage of this by storing debugging
16115 information in the @code{lib/debug} sub-directory of a separate package
16116 output unimaginatively called @code{debug} (@pxref{Packages with
16117 Multiple Outputs}). Users can choose to install the @code{debug} output
16118 of a package when they need it. For instance, the following command
16119 installs the debugging information for the GNU C Library and for GNU
16123 guix package -i glibc:debug guile:debug
16126 GDB must then be told to look for debug files in the user's profile, by
16127 setting the @code{debug-file-directory} variable (consider setting it
16128 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
16132 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
16135 From there on, GDB will pick up debugging information from the
16136 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
16138 In addition, you will most likely want GDB to be able to show the source
16139 code being debugged. To do that, you will have to unpack the source
16140 code of the package of interest (obtained with @code{guix build
16141 --source}, @pxref{Invoking guix build}), and to point GDB to that source
16142 directory using the @code{directory} command (@pxref{Source Path,
16143 @code{directory},, gdb, Debugging with GDB}).
16145 @c XXX: keep me up-to-date
16146 The @code{debug} output mechanism in Guix is implemented by the
16147 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
16148 opt-in---debugging information is available only for the packages
16149 with definitions explicitly declaring a @code{debug} output. This may be
16150 changed to opt-out in the future if our build farm servers can handle
16151 the load. To check whether a package has a @code{debug} output, use
16152 @command{guix package --list-available} (@pxref{Invoking guix package}).
16155 @node Security Updates
16156 @section Security Updates
16158 @cindex security updates
16159 @cindex security vulnerabilities
16160 Occasionally, important security vulnerabilities are discovered in software
16161 packages and must be patched. Guix developers try hard to keep track of
16162 known vulnerabilities and to apply fixes as soon as possible in the
16163 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
16164 containing only security updates.) The @command{guix lint} tool helps
16165 developers find out about vulnerable versions of software packages in the
16170 gnu/packages/base.scm:652:2: glibc-2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
16171 gnu/packages/gcc.scm:334:2: gcc-4.9.3: probably vulnerable to CVE-2015-5276
16172 gnu/packages/image.scm:312:2: openjpeg-2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
16176 @xref{Invoking guix lint}, for more information.
16179 As of version @value{VERSION}, the feature described below is considered
16183 Guix follows a functional
16184 package management discipline (@pxref{Introduction}), which implies
16185 that, when a package is changed, @emph{every package that depends on it}
16186 must be rebuilt. This can significantly slow down the deployment of
16187 fixes in core packages such as libc or Bash, since basically the whole
16188 distribution would need to be rebuilt. Using pre-built binaries helps
16189 (@pxref{Substitutes}), but deployment may still take more time than
16193 To address this, Guix implements @dfn{grafts}, a mechanism that allows
16194 for fast deployment of critical updates without the costs associated
16195 with a whole-distribution rebuild. The idea is to rebuild only the
16196 package that needs to be patched, and then to ``graft'' it onto packages
16197 explicitly installed by the user and that were previously referring to
16198 the original package. The cost of grafting is typically very low, and
16199 order of magnitudes lower than a full rebuild of the dependency chain.
16201 @cindex replacements of packages, for grafts
16202 For instance, suppose a security update needs to be applied to Bash.
16203 Guix developers will provide a package definition for the ``fixed''
16204 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
16205 Packages}). Then, the original package definition is augmented with a
16206 @code{replacement} field pointing to the package containing the bug fix:
16213 (replacement bash-fixed)))
16216 From there on, any package depending directly or indirectly on Bash---as
16217 reported by @command{guix gc --requisites} (@pxref{Invoking guix
16218 gc})---that is installed is automatically ``rewritten'' to refer to
16219 @var{bash-fixed} instead of @var{bash}. This grafting process takes
16220 time proportional to the size of the package, usually less than a
16221 minute for an ``average'' package on a recent machine. Grafting is
16222 recursive: when an indirect dependency requires grafting, then grafting
16223 ``propagates'' up to the package that the user is installing.
16225 Currently, the length of the name and version of the graft and that of
16226 the package it replaces (@var{bash-fixed} and @var{bash} in the example
16227 above) must be equal. This restriction mostly comes from the fact that
16228 grafting works by patching files, including binary files, directly.
16229 Other restrictions may apply: for instance, when adding a graft to a
16230 package providing a shared library, the original shared library and its
16231 replacement must have the same @code{SONAME} and be binary-compatible.
16233 The @option{--no-grafts} command-line option allows you to forcefully
16234 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
16238 guix build bash --no-grafts
16242 returns the store file name of the original Bash, whereas:
16249 returns the store file name of the ``fixed'', replacement Bash. This
16250 allows you to distinguish between the two variants of Bash.
16252 To verify which Bash your whole profile refers to, you can run
16253 (@pxref{Invoking guix gc}):
16256 guix gc -R `readlink -f ~/.guix-profile` | grep bash
16260 @dots{} and compare the store file names that you get with those above.
16261 Likewise for a complete GuixSD system generation:
16264 guix gc -R `guix system build my-config.scm` | grep bash
16267 Lastly, to check which Bash running processes are using, you can use the
16268 @command{lsof} command:
16271 lsof | grep /gnu/store/.*bash
16275 @node Package Modules
16276 @section Package Modules
16278 From a programming viewpoint, the package definitions of the
16279 GNU distribution are provided by Guile modules in the @code{(gnu packages
16280 @dots{})} name space@footnote{Note that packages under the @code{(gnu
16281 packages @dots{})} module name space are not necessarily ``GNU
16282 packages''. This module naming scheme follows the usual Guile module
16283 naming convention: @code{gnu} means that these modules are distributed
16284 as part of the GNU system, and @code{packages} identifies modules that
16285 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
16286 Reference Manual}). For instance, the @code{(gnu packages emacs)}
16287 module exports a variable named @code{emacs}, which is bound to a
16288 @code{<package>} object (@pxref{Defining Packages}).
16290 The @code{(gnu packages @dots{})} module name space is
16291 automatically scanned for packages by the command-line tools. For
16292 instance, when running @code{guix package -i emacs}, all the @code{(gnu
16293 packages @dots{})} modules are scanned until one that exports a package
16294 object whose name is @code{emacs} is found. This package search
16295 facility is implemented in the @code{(gnu packages)} module.
16297 @cindex customization, of packages
16298 @cindex package module search path
16299 Users can store package definitions in modules with different
16300 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
16301 name and module name must match. For instance, the @code{(my-packages
16302 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
16303 relative to the load path specified with @option{--load-path} or
16304 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
16305 guile, GNU Guile Reference Manual}, for details.}. These package definitions
16306 will not be visible by default. Users can invoke commands such as
16307 @command{guix package} and @command{guix build} with the
16308 @code{-e} option so that they know where to find the package. Better
16309 yet, they can use the
16310 @code{-L} option of these commands to make those modules visible
16311 (@pxref{Invoking guix build, @code{--load-path}}), or define the
16312 @code{GUIX_PACKAGE_PATH} environment variable. This environment
16313 variable makes it easy to extend or customize the distribution and is
16314 honored by all the user interfaces.
16316 @defvr {Environment Variable} GUIX_PACKAGE_PATH
16317 This is a colon-separated list of directories to search for additional
16318 package modules. Directories listed in this variable take precedence
16319 over the own modules of the distribution.
16322 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
16323 each package is built based solely on other packages in the
16324 distribution. The root of this dependency graph is a small set of
16325 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
16326 bootstrap)} module. For more information on bootstrapping,
16327 @pxref{Bootstrapping}.
16329 @node Packaging Guidelines
16330 @section Packaging Guidelines
16332 @cindex packages, creating
16333 The GNU distribution is nascent and may well lack some of your favorite
16334 packages. This section describes how you can help make the distribution
16335 grow. @xref{Contributing}, for additional information on how you can
16338 Free software packages are usually distributed in the form of
16339 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
16340 all the source files. Adding a package to the distribution means
16341 essentially two things: adding a @dfn{recipe} that describes how to
16342 build the package, including a list of other packages required to build
16343 it, and adding @dfn{package metadata} along with that recipe, such as a
16344 description and licensing information.
16346 In Guix all this information is embodied in @dfn{package definitions}.
16347 Package definitions provide a high-level view of the package. They are
16348 written using the syntax of the Scheme programming language; in fact,
16349 for each package we define a variable bound to the package definition,
16350 and export that variable from a module (@pxref{Package Modules}).
16351 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
16352 creating packages. For more information on package definitions,
16353 @pxref{Defining Packages}.
16355 Once a package definition is in place, stored in a file in the Guix
16356 source tree, it can be tested using the @command{guix build} command
16357 (@pxref{Invoking guix build}). For example, assuming the new package is
16358 called @code{gnew}, you may run this command from the Guix build tree
16359 (@pxref{Running Guix Before It Is Installed}):
16362 ./pre-inst-env guix build gnew --keep-failed
16365 Using @code{--keep-failed} makes it easier to debug build failures since
16366 it provides access to the failed build tree. Another useful
16367 command-line option when debugging is @code{--log-file}, to access the
16370 If the package is unknown to the @command{guix} command, it may be that
16371 the source file contains a syntax error, or lacks a @code{define-public}
16372 clause to export the package variable. To figure it out, you may load
16373 the module from Guile to get more information about the actual error:
16376 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
16379 Once your package builds correctly, please send us a patch
16380 (@pxref{Contributing}). Well, if you need help, we will be happy to
16381 help you too. Once the patch is committed in the Guix repository, the
16382 new package automatically gets built on the supported platforms by
16383 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
16386 @cindex substituter
16387 Users can obtain the new package definition simply by running
16388 @command{guix pull} (@pxref{Invoking guix pull}). When
16389 @code{hydra.gnu.org} is done building the package, installing the
16390 package automatically downloads binaries from there
16391 (@pxref{Substitutes}). The only place where human intervention is
16392 needed is to review and apply the patch.
16396 * Software Freedom:: What may go into the distribution.
16397 * Package Naming:: What's in a name?
16398 * Version Numbers:: When the name is not enough.
16399 * Synopses and Descriptions:: Helping users find the right package.
16400 * Python Modules:: A touch of British comedy.
16401 * Perl Modules:: Little pearls.
16402 * Java Packages:: Coffee break.
16403 * Fonts:: Fond of fonts.
16406 @node Software Freedom
16407 @subsection Software Freedom
16409 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
16410 @cindex free software
16411 The GNU operating system has been developed so that users can have
16412 freedom in their computing. GNU is @dfn{free software}, meaning that
16413 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
16414 essential freedoms}: to run the program, to study and change the program
16415 in source code form, to redistribute exact copies, and to distribute
16416 modified versions. Packages found in the GNU distribution provide only
16417 software that conveys these four freedoms.
16419 In addition, the GNU distribution follow the
16420 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
16421 software distribution guidelines}. Among other things, these guidelines
16422 reject non-free firmware, recommendations of non-free software, and
16423 discuss ways to deal with trademarks and patents.
16425 Some otherwise free upstream package sources contain a small and optional
16426 subset that violates the above guidelines, for instance because this subset
16427 is itself non-free code. When that happens, the offending items are removed
16428 with appropriate patches or code snippets in the @code{origin} form of the
16429 package (@pxref{Defining Packages}). This way, @code{guix
16430 build --source} returns the ``freed'' source rather than the unmodified
16434 @node Package Naming
16435 @subsection Package Naming
16437 @cindex package name
16438 A package has actually two names associated with it:
16439 First, there is the name of the @emph{Scheme variable}, the one following
16440 @code{define-public}. By this name, the package can be made known in the
16441 Scheme code, for instance as input to another package. Second, there is
16442 the string in the @code{name} field of a package definition. This name
16443 is used by package management commands such as
16444 @command{guix package} and @command{guix build}.
16446 Both are usually the same and correspond to the lowercase conversion of
16447 the project name chosen upstream, with underscores replaced with
16448 hyphens. For instance, GNUnet is available as @code{gnunet}, and
16449 SDL_net as @code{sdl-net}.
16451 We do not add @code{lib} prefixes for library packages, unless these are
16452 already part of the official project name. But @pxref{Python
16453 Modules} and @ref{Perl Modules} for special rules concerning modules for
16454 the Python and Perl languages.
16456 Font package names are handled differently, @pxref{Fonts}.
16459 @node Version Numbers
16460 @subsection Version Numbers
16462 @cindex package version
16463 We usually package only the latest version of a given free software
16464 project. But sometimes, for instance for incompatible library versions,
16465 two (or more) versions of the same package are needed. These require
16466 different Scheme variable names. We use the name as defined
16467 in @ref{Package Naming}
16468 for the most recent version; previous versions use the same name, suffixed
16469 by @code{-} and the smallest prefix of the version number that may
16470 distinguish the two versions.
16472 The name inside the package definition is the same for all versions of a
16473 package and does not contain any version number.
16475 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
16478 (define-public gtk+
16483 (define-public gtk+-2
16486 (version "2.24.20")
16489 If we also wanted GTK+ 3.8.2, this would be packaged as
16491 (define-public gtk+-3.8
16498 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
16499 @c for a discussion of what follows.
16500 @cindex version number, for VCS snapshots
16501 Occasionally, we package snapshots of upstream's version control system
16502 (VCS) instead of formal releases. This should remain exceptional,
16503 because it is up to upstream developers to clarify what the stable
16504 release is. Yet, it is sometimes necessary. So, what should we put in
16505 the @code{version} field?
16507 Clearly, we need to make the commit identifier of the VCS snapshot
16508 visible in the version string, but we also need to make sure that the
16509 version string is monotonically increasing so that @command{guix package
16510 --upgrade} can determine which version is newer. Since commit
16511 identifiers, notably with Git, are not monotonically increasing, we add
16512 a revision number that we increase each time we upgrade to a newer
16513 snapshot. The resulting version string looks like this:
16518 | | `-- upstream commit ID
16520 | `--- Guix package revision
16522 latest upstream version
16525 It is a good idea to strip commit identifiers in the @code{version}
16526 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
16527 aesthetics have a role to play here) as well as problems related to OS
16528 limits such as the maximum shebang length (127 bytes for the Linux
16529 kernel.) It is best to use the full commit identifiers in
16530 @code{origin}s, though, to avoid ambiguities. A typical package
16531 definition may look like this:
16535 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
16536 (revision "1")) ;Guix package revision
16538 (version (string-append "0.9-" revision "."
16539 (string-take commit 7)))
16542 (uri (git-reference
16543 (url "git://example.org/my-package.git")
16545 (sha256 (base32 "1mbikn@dots{}"))
16546 (file-name (string-append "my-package-" version
16552 @node Synopses and Descriptions
16553 @subsection Synopses and Descriptions
16555 @cindex package description
16556 @cindex package synopsis
16557 As we have seen before, each package in GNU@tie{}Guix includes a
16558 synopsis and a description (@pxref{Defining Packages}). Synopses and
16559 descriptions are important: They are what @command{guix package
16560 --search} searches, and a crucial piece of information to help users
16561 determine whether a given package suits their needs. Consequently,
16562 packagers should pay attention to what goes into them.
16564 Synopses must start with a capital letter and must not end with a
16565 period. They must not start with ``a'' or ``the'', which usually does
16566 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
16567 tool that frobs files''. The synopsis should say what the package
16568 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
16569 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
16570 matching a pattern''.
16572 Keep in mind that the synopsis must be meaningful for a very wide
16573 audience. For example, ``Manipulate alignments in the SAM format''
16574 might make sense for a seasoned bioinformatics researcher, but might be
16575 fairly unhelpful or even misleading to a non-specialized audience. It
16576 is a good idea to come up with a synopsis that gives an idea of the
16577 application domain of the package. In this example, this might give
16578 something like ``Manipulate nucleotide sequence alignments'', which
16579 hopefully gives the user a better idea of whether this is what they are
16582 Descriptions should take between five and ten lines. Use full
16583 sentences, and avoid using acronyms without first introducing them.
16584 Please avoid marketing phrases such as ``world-leading'',
16585 ``industrial-strength'', and ``next-generation'', and avoid superlatives
16586 like ``the most advanced''---they are not helpful to users looking for a
16587 package and may even sound suspicious. Instead, try to be factual,
16588 mentioning use cases and features.
16590 @cindex Texinfo markup, in package descriptions
16591 Descriptions can include Texinfo markup, which is useful to introduce
16592 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
16593 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
16594 should be careful when using some characters for example @samp{@@} and
16595 curly braces which are the basic special characters in Texinfo
16596 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
16597 such as @command{guix package --show} take care of rendering it
16600 Synopses and descriptions are translated by volunteers
16601 @uref{http://translationproject.org/domain/guix-packages.html, at the
16602 Translation Project} so that as many users as possible can read them in
16603 their native language. User interfaces search them and display them in
16604 the language specified by the current locale.
16606 Translation is a lot of work so, as a packager, please pay even more
16607 attention to your synopses and descriptions as every change may entail
16608 additional work for translators. In order to help them, it is possible
16609 to make recommendations or instructions visible to them by inserting
16610 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
16614 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
16615 (description "ARandR is designed to provide a simple visual front end
16616 for the X11 resize-and-rotate (RandR) extension. @dots{}")
16620 @node Python Modules
16621 @subsection Python Modules
16624 We currently package Python 2 and Python 3, under the Scheme variable names
16625 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
16626 To avoid confusion and naming clashes with other programming languages, it
16627 seems desirable that the name of a package for a Python module contains
16628 the word @code{python}.
16630 Some modules are compatible with only one version of Python, others with both.
16631 If the package Foo compiles only with Python 3, we name it
16632 @code{python-foo}; if it compiles only with Python 2, we name it
16633 @code{python2-foo}. If it is compatible with both versions, we create two
16634 packages with the corresponding names.
16636 If a project already contains the word @code{python}, we drop this;
16637 for instance, the module python-dateutil is packaged under the names
16638 @code{python-dateutil} and @code{python2-dateutil}. If the project name
16639 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
16642 @subsubsection Specifying Dependencies
16643 @cindex inputs, for Python packages
16645 Dependency information for Python packages is usually available in the
16646 package source tree, with varying degrees of accuracy: in the
16647 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
16649 Your mission, when writing a recipe for a Python package, is to map
16650 these dependencies to the appropriate type of ``input'' (@pxref{package
16651 Reference, inputs}). Although the @code{pypi} importer normally does a
16652 good job (@pxref{Invoking guix import}), you may want to check the
16653 following check list to determine which dependency goes where.
16658 We currently package Python 2 with @code{setuptools} and @code{pip}
16659 installed like Python 3.4 has per default. Thus you don't need to
16660 specify either of these as an input. @command{guix lint} will warn you
16664 Python dependencies required at run time go into
16665 @code{propagated-inputs}. They are typically defined with the
16666 @code{install_requires} keyword in @file{setup.py}, or in the
16667 @file{requirements.txt} file.
16670 Python packages required only at build time---e.g., those listed with
16671 the @code{setup_requires} keyword in @file{setup.py}---or only for
16672 testing---e.g., those in @code{tests_require}---go into
16673 @code{native-inputs}. The rationale is that (1) they do not need to be
16674 propagated because they are not needed at run time, and (2) in a
16675 cross-compilation context, it's the ``native'' input that we'd want.
16677 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
16678 frameworks. Of course if any of these packages is also required at
16679 run-time, it needs to go to @code{propagated-inputs}.
16682 Anything that does not fall in the previous categories goes to
16683 @code{inputs}, for example programs or C libraries required for building
16684 Python packages containing C extensions.
16687 If a Python package has optional dependencies (@code{extras_require}),
16688 it is up to you to decide whether to add them or not, based on their
16689 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
16696 @subsection Perl Modules
16699 Perl programs standing for themselves are named as any other package,
16700 using the lowercase upstream name.
16701 For Perl packages containing a single class, we use the lowercase class name,
16702 replace all occurrences of @code{::} by dashes and prepend the prefix
16704 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
16705 Modules containing several classes keep their lowercase upstream name and
16706 are also prepended by @code{perl-}. Such modules tend to have the word
16707 @code{perl} somewhere in their name, which gets dropped in favor of the
16708 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
16711 @node Java Packages
16712 @subsection Java Packages
16715 Java programs standing for themselves are named as any other package,
16716 using the lowercase upstream name.
16718 To avoid confusion and naming clashes with other programming languages,
16719 it is desirable that the name of a package for a Java package is
16720 prefixed with @code{java-}. If a project already contains the word
16721 @code{java}, we drop this; for instance, the package @code{ngsjava} is
16722 packaged under the name @code{java-ngs}.
16724 For Java packages containing a single class or a small class hierarchy,
16725 we use the lowercase class name, replace all occurrences of @code{.} by
16726 dashes and prepend the prefix @code{java-}. So the class
16727 @code{apache.commons.cli} becomes package
16728 @code{java-apache-commons-cli}.
16735 For fonts that are in general not installed by a user for typesetting
16736 purposes, or that are distributed as part of a larger software package,
16737 we rely on the general packaging rules for software; for instance, this
16738 applies to the fonts delivered as part of the X.Org system or fonts that
16739 are part of TeX Live.
16741 To make it easier for a user to search for fonts, names for other packages
16742 containing only fonts are constructed as follows, independently of the
16743 upstream package name.
16745 The name of a package containing only one font family starts with
16746 @code{font-}; it is followed by the foundry name and a dash @code{-}
16747 if the foundry is known, and the font family name, in which spaces are
16748 replaced by dashes (and as usual, all upper case letters are transformed
16750 For example, the Gentium font family by SIL is packaged under the name
16751 @code{font-sil-gentium}.
16753 For a package containing several font families, the name of the collection
16754 is used in the place of the font family name.
16755 For instance, the Liberation fonts consist of three families,
16756 Liberation Sans, Liberation Serif and Liberation Mono.
16757 These could be packaged separately under the names
16758 @code{font-liberation-sans} and so on; but as they are distributed together
16759 under a common name, we prefer to package them together as
16760 @code{font-liberation}.
16762 In the case where several formats of the same font family or font collection
16763 are packaged separately, a short form of the format, prepended by a dash,
16764 is added to the package name. We use @code{-ttf} for TrueType fonts,
16765 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
16770 @node Bootstrapping
16771 @section Bootstrapping
16773 @c Adapted from the ELS 2013 paper.
16775 @cindex bootstrapping
16777 Bootstrapping in our context refers to how the distribution gets built
16778 ``from nothing''. Remember that the build environment of a derivation
16779 contains nothing but its declared inputs (@pxref{Introduction}). So
16780 there's an obvious chicken-and-egg problem: how does the first package
16781 get built? How does the first compiler get compiled? Note that this is
16782 a question of interest only to the curious hacker, not to the regular
16783 user, so you can shamelessly skip this section if you consider yourself
16784 a ``regular user''.
16786 @cindex bootstrap binaries
16787 The GNU system is primarily made of C code, with libc at its core. The
16788 GNU build system itself assumes the availability of a Bourne shell and
16789 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
16790 `grep'. Furthermore, build programs---programs that run
16791 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
16792 (@pxref{Derivations}). Consequently, to be able to build anything at
16793 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
16794 Binutils, libc, and the other packages mentioned above---the
16795 @dfn{bootstrap binaries}.
16797 These bootstrap binaries are ``taken for granted'', though we can also
16798 re-create them if needed (more on that later).
16800 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
16802 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
16803 @c large image, it's hard to scroll. Oh well.
16804 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
16806 The figure above shows the very beginning of the dependency graph of the
16807 distribution, corresponding to the package definitions of the @code{(gnu
16808 packages bootstrap)} module. A similar figure can be generated with
16809 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
16812 guix graph -t derivation \
16813 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
16817 At this level of detail, things are
16818 slightly complex. First, Guile itself consists of an ELF executable,
16819 along with many source and compiled Scheme files that are dynamically
16820 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
16821 tarball shown in this graph. This tarball is part of Guix's ``source''
16822 distribution, and gets inserted into the store with @code{add-to-store}
16823 (@pxref{The Store}).
16825 But how do we write a derivation that unpacks this tarball and adds it
16826 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
16827 derivation---the first one that gets built---uses @code{bash} as its
16828 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
16829 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
16830 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
16831 the Guix source distribution, whose sole purpose is to allow the Guile
16832 tarball to be unpacked.
16834 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
16835 Guile that can be used to run subsequent build programs. Its first task
16836 is to download tarballs containing the other pre-built binaries---this
16837 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
16838 @code{ftp-client.scm} are used for this purpose. The
16839 @code{module-import.drv} derivations import those modules in a directory
16840 in the store, using the original layout. The
16841 @code{module-import-compiled.drv} derivations compile those modules, and
16842 write them in an output directory with the right layout. This
16843 corresponds to the @code{#:modules} argument of
16844 @code{build-expression->derivation} (@pxref{Derivations}).
16846 Finally, the various tarballs are unpacked by the
16847 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
16848 etc., at which point we have a working C tool chain.
16851 @unnumberedsubsec Building the Build Tools
16853 Bootstrapping is complete when we have a full tool chain that does not
16854 depend on the pre-built bootstrap tools discussed above. This
16855 no-dependency requirement is verified by checking whether the files of
16856 the final tool chain contain references to the @file{/gnu/store}
16857 directories of the bootstrap inputs. The process that leads to this
16858 ``final'' tool chain is described by the package definitions found in
16859 the @code{(gnu packages commencement)} module.
16861 The @command{guix graph} command allows us to ``zoom out'' compared to
16862 the graph above, by looking at the level of package objects instead of
16863 individual derivations---remember that a package may translate to
16864 several derivations, typically one derivation to download its source,
16865 one to build the Guile modules it needs, and one to actually build the
16866 package from source. The command:
16869 guix graph -t bag \
16870 -e '(@@@@ (gnu packages commencement)
16871 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
16875 produces the dependency graph leading to the ``final'' C
16876 library@footnote{You may notice the @code{glibc-intermediate} label,
16877 suggesting that it is not @emph{quite} final, but as a good
16878 approximation, we will consider it final.}, depicted below.
16880 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
16882 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
16883 The first tool that gets built with the bootstrap binaries is
16884 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
16885 for all the following packages. From there Findutils and Diffutils get
16888 Then come the first-stage Binutils and GCC, built as pseudo cross
16889 tools---i.e., with @code{--target} equal to @code{--host}. They are
16890 used to build libc. Thanks to this cross-build trick, this libc is
16891 guaranteed not to hold any reference to the initial tool chain.
16893 From there the final Binutils and GCC (not shown above) are built.
16895 from the final Binutils, and links programs against the just-built libc.
16896 This tool chain is used to build the other packages used by Guix and by
16897 the GNU Build System: Guile, Bash, Coreutils, etc.
16899 And voilà! At this point we have the complete set of build tools that
16900 the GNU Build System expects. These are in the @code{%final-inputs}
16901 variable of the @code{(gnu packages commencement)} module, and are
16902 implicitly used by any package that uses @code{gnu-build-system}
16903 (@pxref{Build Systems, @code{gnu-build-system}}).
16906 @unnumberedsubsec Building the Bootstrap Binaries
16908 @cindex bootstrap binaries
16909 Because the final tool chain does not depend on the bootstrap binaries,
16910 those rarely need to be updated. Nevertheless, it is useful to have an
16911 automated way to produce them, should an update occur, and this is what
16912 the @code{(gnu packages make-bootstrap)} module provides.
16914 The following command builds the tarballs containing the bootstrap
16915 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
16916 of Coreutils and other basic command-line tools):
16919 guix build bootstrap-tarballs
16922 The generated tarballs are those that should be referred to in the
16923 @code{(gnu packages bootstrap)} module mentioned at the beginning of
16926 Still here? Then perhaps by now you've started to wonder: when do we
16927 reach a fixed point? That is an interesting question! The answer is
16928 unknown, but if you would like to investigate further (and have
16929 significant computational and storage resources to do so), then let us
16933 @section Porting to a New Platform
16935 As discussed above, the GNU distribution is self-contained, and
16936 self-containment is achieved by relying on pre-built ``bootstrap
16937 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
16938 operating system kernel, CPU architecture, and application binary
16939 interface (ABI). Thus, to port the distribution to a platform that is
16940 not yet supported, one must build those bootstrap binaries, and update
16941 the @code{(gnu packages bootstrap)} module to use them on that platform.
16943 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
16944 When everything goes well, and assuming the GNU tool chain supports the
16945 target platform, this can be as simple as running a command like this
16949 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
16952 For this to work, the @code{glibc-dynamic-linker} procedure in
16953 @code{(gnu packages bootstrap)} must be augmented to return the right
16954 file name for libc's dynamic linker on that platform; likewise,
16955 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
16956 taught about the new platform.
16958 Once these are built, the @code{(gnu packages bootstrap)} module needs
16959 to be updated to refer to these binaries on the target platform. That
16960 is, the hashes and URLs of the bootstrap tarballs for the new platform
16961 must be added alongside those of the currently supported platforms. The
16962 bootstrap Guile tarball is treated specially: it is expected to be
16963 available locally, and @file{gnu/local.mk} has rules do download it for
16964 the supported architectures; a rule for the new platform must be added
16967 In practice, there may be some complications. First, it may be that the
16968 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
16969 above) is not recognized by all the GNU tools. Typically, glibc
16970 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
16971 configure flag (see @code{gcc.scm} for examples of how to handle this).
16972 Second, some of the required packages could fail to build for that
16973 platform. Lastly, the generated binaries could be broken for some
16976 @c *********************************************************************
16977 @include contributing.texi
16979 @c *********************************************************************
16980 @node Acknowledgments
16981 @chapter Acknowledgments
16983 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
16984 which was designed and
16985 implemented by Eelco Dolstra, with contributions from other people (see
16986 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
16987 management, and promoted unprecedented features, such as transactional
16988 package upgrades and rollbacks, per-user profiles, and referentially
16989 transparent build processes. Without this work, Guix would not exist.
16991 The Nix-based software distributions, Nixpkgs and NixOS, have also been
16992 an inspiration for Guix.
16994 GNU@tie{}Guix itself is a collective work with contributions from a
16995 number of people. See the @file{AUTHORS} file in Guix for more
16996 information on these fine people. The @file{THANKS} file lists people
16997 who have helped by reporting bugs, taking care of the infrastructure,
16998 providing artwork and themes, making suggestions, and more---thank you!
17001 @c *********************************************************************
17002 @node GNU Free Documentation License
17003 @appendix GNU Free Documentation License
17004 @cindex license, GNU Free Documentation License
17005 @include fdl-1.3.texi
17007 @c *********************************************************************
17008 @node Concept Index
17009 @unnumbered Concept Index
17012 @node Programming Index
17013 @unnumbered Programming Index
17014 @syncodeindex tp fn
17015 @syncodeindex vr fn
17020 @c Local Variables:
17021 @c ispell-local-dictionary: "american";