6 @documentencoding UTF-8
7 @settitle GNU Guix Reference Manual
13 Copyright @copyright{} 2012, 2013, 2014, 2015, 2016 Ludovic Courtès@*
14 Copyright @copyright{} 2013, 2014, 2016 Andreas Enge@*
15 Copyright @copyright{} 2013 Nikita Karetnikov@*
16 Copyright @copyright{} 2015, 2016 Mathieu Lirzin@*
17 Copyright @copyright{} 2014 Pierre-Antoine Rault@*
18 Copyright @copyright{} 2015 Taylan Ulrich Bayırlı/Kammer@*
19 Copyright @copyright{} 2015, 2016 Leo Famulari@*
20 Copyright @copyright{} 2016 Ben Woodcroft@*
21 Copyright @copyright{} 2016 Chris Marusich@*
22 Copyright @copyright{} 2016 Efraim Flashner
24 Permission is granted to copy, distribute and/or modify this document
25 under the terms of the GNU Free Documentation License, Version 1.3 or
26 any later version published by the Free Software Foundation; with no
27 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
28 copy of the license is included in the section entitled ``GNU Free
29 Documentation License''.
32 @dircategory System administration
34 * Guix: (guix). Manage installed software and system configuration.
35 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
36 * guix build: (guix)Invoking guix build. Building packages.
37 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
38 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
39 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
42 @dircategory Software development
44 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
49 * Guix user interface: (guix)Emacs Interface. Package management from the comfort of Emacs.
54 @title GNU Guix Reference Manual
55 @subtitle Using the GNU Guix Functional Package Manager
56 @author The GNU Guix Developers
59 @vskip 0pt plus 1filll
60 Edition @value{EDITION} @*
68 @c *********************************************************************
72 This document describes GNU Guix version @value{VERSION}, a functional
73 package management tool written for the GNU system.
76 * Introduction:: What is Guix about?
77 * Installation:: Installing Guix.
78 * Package Management:: Package installation, upgrade, etc.
79 * Emacs Interface:: Using Guix from Emacs.
80 * Programming Interface:: Using Guix in Scheme.
81 * Utilities:: Package management commands.
82 * GNU Distribution:: Software for your friendly GNU system.
83 * Contributing:: Your help needed!
85 * Acknowledgments:: Thanks!
86 * GNU Free Documentation License:: The license of this manual.
87 * Concept Index:: Concepts.
88 * Programming Index:: Data types, functions, and variables.
91 --- The Detailed Node Listing ---
95 * Binary Installation:: Getting Guix running in no time!
96 * Requirements:: Software needed to build and run Guix.
97 * Running the Test Suite:: Testing Guix.
98 * Setting Up the Daemon:: Preparing the build daemon's environment.
99 * Invoking guix-daemon:: Running the build daemon.
100 * Application Setup:: Application-specific setup.
102 Setting Up the Daemon
104 * Build Environment Setup:: Preparing the isolated build environment.
105 * Daemon Offload Setup:: Offloading builds to remote machines.
109 * Features:: How Guix will make your life brighter.
110 * Invoking guix package:: Package installation, removal, etc.
111 * Substitutes:: Downloading pre-built binaries.
112 * Packages with Multiple Outputs:: Single source package, multiple outputs.
113 * Invoking guix gc:: Running the garbage collector.
114 * Invoking guix pull:: Fetching the latest Guix and distribution.
115 * Invoking guix archive:: Exporting and importing store files.
119 * Initial Setup: Emacs Initial Setup. Preparing @file{~/.emacs}.
120 * Package Management: Emacs Package Management. Managing packages and generations.
121 * Licenses: Emacs Licenses. Interface for licenses of Guix packages.
122 * Package Source Locations: Emacs Package Locations. Interface for package location files.
123 * Popup Interface: Emacs Popup Interface. Magit-like interface for guix commands.
124 * Prettify Mode: Emacs Prettify. Abbreviating @file{/gnu/store/@dots{}} file names.
125 * Build Log Mode: Emacs Build Log. Highlighting Guix build logs.
126 * Completions: Emacs Completions. Completing @command{guix} shell command.
127 * Development: Emacs Development. Tools for Guix developers.
128 * Hydra: Emacs Hydra. Interface for Guix build farm.
130 Programming Interface
132 * Defining Packages:: Defining new packages.
133 * Build Systems:: Specifying how packages are built.
134 * The Store:: Manipulating the package store.
135 * Derivations:: Low-level interface to package derivations.
136 * The Store Monad:: Purely functional interface to the store.
137 * G-Expressions:: Manipulating build expressions.
141 * package Reference:: The package data type.
142 * origin Reference:: The origin data type.
146 * Invoking guix build:: Building packages from the command line.
147 * Invoking guix edit:: Editing package definitions.
148 * Invoking guix download:: Downloading a file and printing its hash.
149 * Invoking guix hash:: Computing the cryptographic hash of a file.
150 * Invoking guix import:: Importing package definitions.
151 * Invoking guix refresh:: Updating package definitions.
152 * Invoking guix lint:: Finding errors in package definitions.
153 * Invoking guix size:: Profiling disk usage.
154 * Invoking guix graph:: Visualizing the graph of packages.
155 * Invoking guix environment:: Setting up development environments.
156 * Invoking guix publish:: Sharing substitutes.
157 * Invoking guix challenge:: Challenging substitute servers.
158 * Invoking guix container:: Process isolation.
160 Invoking @command{guix build}
162 * Common Build Options:: Build options for most commands.
163 * Package Transformation Options:: Creating variants of packages.
164 * Additional Build Options:: Options specific to 'guix build'.
168 * System Installation:: Installing the whole operating system.
169 * System Configuration:: Configuring the operating system.
170 * Installing Debugging Files:: Feeding the debugger.
171 * Security Updates:: Deploying security fixes quickly.
172 * Package Modules:: Packages from the programmer's viewpoint.
173 * Packaging Guidelines:: Growing the distribution.
174 * Bootstrapping:: GNU/Linux built from scratch.
175 * Porting:: Targeting another platform or kernel.
179 * Limitations:: What you can expect.
180 * Hardware Considerations:: Supported hardware.
181 * USB Stick Installation:: Preparing the installation medium.
182 * Preparing for Installation:: Networking, partitioning, etc.
183 * Proceeding with the Installation:: The real thing.
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 * Networking Services:: Network setup, SSH daemon, etc.
208 * X Window:: Graphical display.
209 * Desktop Services:: D-Bus and desktop services.
210 * Database Services:: SQL databases.
211 * Mail Services:: IMAP, POP3, SMTP, and all that.
212 * Web Services:: Web servers.
213 * Various Services:: Other services.
217 * Service Composition:: The model for composing services.
218 * Service Types and Services:: Types and services.
219 * Service Reference:: API reference.
220 * Shepherd Services:: A particular type of service.
224 * Software Freedom:: What may go into the distribution.
225 * Package Naming:: What's in a name?
226 * Version Numbers:: When the name is not enough.
227 * Synopses and Descriptions:: Helping users find the right package.
228 * Python Modules:: Taming the snake.
229 * Perl Modules:: Little pearls.
230 * Java Packages:: Coffee break.
231 * Fonts:: Fond of fonts.
235 * Building from Git:: The latest and greatest.
236 * Running Guix Before It Is Installed:: Hacker tricks.
237 * The Perfect Setup:: The right tools.
238 * Coding Style:: Hygiene of the contributor.
239 * Submitting Patches:: Share your work.
243 * Programming Paradigm:: How to compose your elements.
244 * Modules:: Where to store your code?
245 * Data Types and Pattern Matching:: Implementing data structures.
246 * Formatting Code:: Writing conventions.
251 @c *********************************************************************
253 @chapter Introduction
256 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
257 using the international phonetic alphabet (IPA).} is a package
258 management tool for the GNU system. Guix makes it easy for unprivileged
259 users to install, upgrade, or remove packages, to roll back to a
260 previous package set, to build packages from source, and generally
261 assists with the creation and maintenance of software environments.
263 @cindex user interfaces
264 Guix provides a command-line package management interface
265 (@pxref{Invoking guix package}), a set of command-line utilities
266 (@pxref{Utilities}), a visual user interface in Emacs (@pxref{Emacs
267 Interface}), as well as Scheme programming interfaces
268 (@pxref{Programming Interface}).
270 Its @dfn{build daemon} is responsible for building packages on behalf of
271 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
272 binaries from authorized sources (@pxref{Substitutes}).
274 @cindex extensibility of the distribution
275 @cindex customization of packages
276 Guix includes package definitions for many GNU and non-GNU packages, all
277 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
278 user's computing freedom}. It is @emph{extensible}: users can write
279 their own package definitions (@pxref{Defining Packages}) and make them
280 available as independent package modules (@pxref{Package Modules}). It
281 is also @emph{customizable}: users can @emph{derive} specialized package
282 definitions from existing ones, including from the command line
283 (@pxref{Package Transformation Options}).
285 @cindex Guix System Distribution
287 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
288 where it complements the available tools without interference
289 (@pxref{Installation}), or you can use it as part of the standalone
290 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
291 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
292 system configuration and Guix takes care of instantiating the
293 configuration in a transactional, reproducible, and stateless fashion
294 (@pxref{System Configuration}).
296 @cindex functional package management
297 Under the hood, Guix implements the @dfn{functional package management}
298 discipline pioneered by Nix (@pxref{Acknowledgments}).
299 In Guix, the package build and installation process is seen
300 as a @emph{function}, in the mathematical sense. That function takes inputs,
301 such as build scripts, a compiler, and libraries, and
302 returns an installed package. As a pure function, its result depends
303 solely on its inputs---for instance, it cannot refer to software or
304 scripts that were not explicitly passed as inputs. A build function
305 always produces the same result when passed a given set of inputs. It
306 cannot alter the environment of the running system in
307 any way; for instance, it cannot create, modify, or delete files outside
308 of its build and installation directories. This is achieved by running
309 build processes in isolated environments (or @dfn{containers}), where only their
310 explicit inputs are visible.
313 The result of package build functions is @dfn{cached} in the file
314 system, in a special directory called @dfn{the store} (@pxref{The
315 Store}). Each package is installed in a directory of its own in the
316 store---by default under @file{/gnu/store}. The directory name contains
317 a hash of all the inputs used to build that package; thus, changing an
318 input yields a different directory name.
320 This approach is the foundation for the salient features of Guix: support
321 for transactional package upgrade and rollback, per-user installation, and
322 garbage collection of packages (@pxref{Features}).
325 @c *********************************************************************
327 @chapter Installation
329 GNU Guix is available for download from its website at
330 @url{http://www.gnu.org/software/guix/}. This section describes the
331 software requirements of Guix, as well as how to install it and get
334 Note that this section is concerned with the installation of the package
335 manager, which can be done on top of a running GNU/Linux system. If,
336 instead, you want to install the complete GNU operating system,
337 @pxref{System Installation}.
339 @cindex foreign distro
340 When installed on a running GNU/Linux system---thereafter called a
341 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
342 without interference. Its data lives exclusively in two directories,
343 usually @file{/gnu/store} and @file{/var/guix}; other files on your
344 system, such as @file{/etc}, are left untouched.
347 * Binary Installation:: Getting Guix running in no time!
348 * Requirements:: Software needed to build and run Guix.
349 * Running the Test Suite:: Testing Guix.
350 * Setting Up the Daemon:: Preparing the build daemon's environment.
351 * Invoking guix-daemon:: Running the build daemon.
352 * Application Setup:: Application-specific setup.
355 @node Binary Installation
356 @section Binary Installation
358 This section describes how to install Guix on an arbitrary system from a
359 self-contained tarball providing binaries for Guix and for all its
360 dependencies. This is often quicker than installing from source, which
361 is described in the next sections. The only requirement is to have
364 Installing goes along these lines:
368 Download the binary tarball from
369 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
370 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
371 already running the kernel Linux, and so on.
373 Make sure to download the associated @file{.sig} file and to verify the
374 authenticity of the tarball against it, along these lines:
377 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
378 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
381 If that command fails because you do not have the required public key,
382 then run this command to import it:
385 $ gpg --keyserver pgp.mit.edu --recv-keys 090B11993D9AEBB5
389 and rerun the @code{gpg --verify} command.
396 # tar --warning=no-timestamp -xf \
397 guix-binary-@value{VERSION}.@var{system}.tar.xz
398 # mv var/guix /var/ && mv gnu /
401 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
402 The latter contains a ready-to-use profile for @code{root} (see next
405 Do @emph{not} unpack the tarball on a working Guix system since that
406 would overwrite its own essential files.
408 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
409 not emit warnings about ``implausibly old time stamps'' (such
410 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
412 They stem from the fact that all the
413 files in the archive have their modification time set to zero (which
414 means January 1st, 1970.) This is done on purpose to make sure the
415 archive content is independent of its creation time, thus making it
419 Make @code{root}'s profile available under @file{~/.guix-profile}:
422 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
427 Create the group and user accounts for build users as explained below
428 (@pxref{Build Environment Setup}).
431 Run the daemon, and set it to automatically start on boot.
433 If your host distro uses the systemd init system, this can be achieved
437 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
439 # systemctl start guix-daemon && systemctl enable guix-daemon
442 If your host distro uses the Upstart init system:
445 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
449 Otherwise, you can still start the daemon manually with:
452 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
456 Make the @command{guix} command available to other users on the machine,
460 # mkdir -p /usr/local/bin
462 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
465 It is also a good idea to make the Info version of this manual available
469 # mkdir -p /usr/local/share/info
470 # cd /usr/local/share/info
471 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
475 That way, assuming @file{/usr/local/share/info} is in the search path,
476 running @command{info guix} will open this manual (@pxref{Other Info
477 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
481 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
482 (@pxref{Substitutes}), authorize them:
485 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
489 This completes root-level install of Guix. Each user will need to
490 perform additional steps to make their Guix envionment ready for use,
491 @pxref{Application Setup}.
493 You can confirm that Guix is working by installing a sample package into
497 # guix package -i hello
500 The @code{guix} package must remain available in @code{root}'s profile,
501 or it would become subject to garbage collection---in which case you
502 would find yourself badly handicapped by the lack of the @command{guix}
503 command. In other words, do not remove @code{guix} by running
504 @code{guix package -r guix}.
506 The binary installation tarball can be (re)produced and verified simply
507 by running the following command in the Guix source tree:
510 make guix-binary.@var{system}.tar.xz
515 @section Requirements
517 This section lists requirements when building Guix from source. The
518 build procedure for Guix is the same as for other GNU software, and is
519 not covered here. Please see the files @file{README} and @file{INSTALL}
520 in the Guix source tree for additional details.
522 GNU Guix depends on the following packages:
525 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.7 or later;
526 @item @url{http://gnupg.org/, GNU libgcrypt};
527 @item @url{http://www.gnu.org/software/make/, GNU Make}.
530 The following dependencies are optional:
534 Installing @uref{http://gnutls.org/, GnuTLS-Guile} will allow you to
535 access @code{https} URLs for substitutes, which is highly recommended
536 (@pxref{Substitutes}). It also allows you to access HTTPS URLs with the
537 @command{guix download} command (@pxref{Invoking guix download}), the
538 @command{guix import pypi} command, and the @command{guix import cpan}
539 command. @xref{Guile Preparations, how to install the GnuTLS bindings
540 for Guile,, gnutls-guile, GnuTLS-Guile}.
544 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
545 allow you to use the @command{guix import pypi} command (@pxref{Invoking
546 guix import}). It is of
547 interest primarily for developers and not for casual users.
550 Unless @code{--disable-daemon} was passed to @command{configure}, the
551 following packages are also needed:
554 @item @url{http://sqlite.org, SQLite 3};
555 @item @url{http://www.bzip.org, libbz2};
556 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
560 When configuring Guix on a system that already has a Guix installation,
561 be sure to specify the same state directory as the existing installation
562 using the @code{--localstatedir} option of the @command{configure}
563 script (@pxref{Directory Variables, @code{localstatedir},, standards,
564 GNU Coding Standards}). The @command{configure} script protects against
565 unintended misconfiguration of @var{localstatedir} so you do not
566 inadvertently corrupt your store (@pxref{The Store}).
568 When a working installation of @url{http://nixos.org/nix/, the Nix package
569 manager} is available, you
570 can instead configure Guix with @code{--disable-daemon}. In that case,
571 Nix replaces the three dependencies above.
573 Guix is compatible with Nix, so it is possible to share the same store
574 between both. To do so, you must pass @command{configure} not only the
575 same @code{--with-store-dir} value, but also the same
576 @code{--localstatedir} value. The latter is essential because it
577 specifies where the database that stores metadata about the store is
578 located, among other things. The default values for Nix are
579 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
580 Note that @code{--disable-daemon} is not required if
581 your goal is to share the store with Nix.
583 @node Running the Test Suite
584 @section Running the Test Suite
586 After a successful @command{configure} and @code{make} run, it is a good
587 idea to run the test suite. It can help catch issues with the setup or
588 environment, or bugs in Guix itself---and really, reporting test
589 failures is a good way to help improve the software. To run the test
596 Test cases can run in parallel: you can use the @code{-j} option of
597 GNU@tie{}make to speed things up. The first run may take a few minutes
598 on a recent machine; subsequent runs will be faster because the store
599 that is created for test purposes will already have various things in
602 It is also possible to run a subset of the tests by defining the
603 @code{TESTS} makefile variable as in this example:
606 make check TESTS="tests/store.scm tests/cpio.scm"
609 By default, tests results are displayed at a file level. In order to
610 see the details of every individual test cases, it is possible to define
611 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
614 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
617 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
618 @file{test-suite.log} file. Please specify the Guix version being used
619 as well as version numbers of the dependencies (@pxref{Requirements}) in
622 @node Setting Up the Daemon
623 @section Setting Up the Daemon
626 Operations such as building a package or running the garbage collector
627 are all performed by a specialized process, the @dfn{build daemon}, on
628 behalf of clients. Only the daemon may access the store and its
629 associated database. Thus, any operation that manipulates the store
630 goes through the daemon. For instance, command-line tools such as
631 @command{guix package} and @command{guix build} communicate with the
632 daemon (@i{via} remote procedure calls) to instruct it what to do.
634 The following sections explain how to prepare the build daemon's
635 environment. See also @ref{Substitutes}, for information on how to allow
636 the daemon to download pre-built binaries.
639 * Build Environment Setup:: Preparing the isolated build environment.
640 * Daemon Offload Setup:: Offloading builds to remote machines.
643 @node Build Environment Setup
644 @subsection Build Environment Setup
646 In a standard multi-user setup, Guix and its daemon---the
647 @command{guix-daemon} program---are installed by the system
648 administrator; @file{/gnu/store} is owned by @code{root} and
649 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
650 Guix tools to build packages or otherwise access the store, and the
651 daemon will do it on their behalf, ensuring that the store is kept in a
652 consistent state, and allowing built packages to be shared among users.
655 When @command{guix-daemon} runs as @code{root}, you may not want package
656 build processes themselves to run as @code{root} too, for obvious
657 security reasons. To avoid that, a special pool of @dfn{build users}
658 should be created for use by build processes started by the daemon.
659 These build users need not have a shell and a home directory: they will
660 just be used when the daemon drops @code{root} privileges in build
661 processes. Having several such users allows the daemon to launch
662 distinct build processes under separate UIDs, which guarantees that they
663 do not interfere with each other---an essential feature since builds are
664 regarded as pure functions (@pxref{Introduction}).
666 On a GNU/Linux system, a build user pool may be created like this (using
667 Bash syntax and the @code{shadow} commands):
669 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
670 @c for why `-G' is needed.
672 # groupadd --system guixbuild
673 # for i in `seq -w 1 10`;
675 useradd -g guixbuild -G guixbuild \
676 -d /var/empty -s `which nologin` \
677 -c "Guix build user $i" --system \
683 The number of build users determines how many build jobs may run in
684 parallel, as specified by the @option{--max-jobs} option
685 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). The
686 @code{guix-daemon} program may then be run as @code{root} with the
687 following command@footnote{If your machine uses the systemd init system,
688 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
689 file in @file{/etc/systemd/system} will ensure that
690 @command{guix-daemon} is automatically started. Similarly, if your
691 machine uses the Upstart init system, drop the
692 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
693 file in @file{/etc/init}.}:
696 # guix-daemon --build-users-group=guixbuild
701 This way, the daemon starts build processes in a chroot, under one of
702 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
703 environment contains nothing but:
705 @c Keep this list in sync with libstore/build.cc! -----------------------
708 a minimal @code{/dev} directory, created mostly independently from the
709 host @code{/dev}@footnote{``Mostly'', because while the set of files
710 that appear in the chroot's @code{/dev} is fixed, most of these files
711 can only be created if the host has them.};
714 the @code{/proc} directory; it only shows the processes of the container
715 since a separate PID name space is used;
718 @file{/etc/passwd} with an entry for the current user and an entry for
722 @file{/etc/group} with an entry for the user's group;
725 @file{/etc/hosts} with an entry that maps @code{localhost} to
729 a writable @file{/tmp} directory.
732 You can influence the directory where the daemon stores build trees
733 @i{via} the @code{TMPDIR} environment variable. However, the build tree
734 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
735 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
736 This way, the value of @code{TMPDIR} does not leak inside build
737 environments, which avoids discrepancies in cases where build processes
738 capture the name of their build tree.
741 The daemon also honors the @code{http_proxy} environment variable for
742 HTTP downloads it performs, be it for fixed-output derivations
743 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
745 If you are installing Guix as an unprivileged user, it is still possible
746 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
747 However, build processes will not be isolated from one another, and not
748 from the rest of the system. Thus, build processes may interfere with
749 each other, and may access programs, libraries, and other files
750 available on the system---making it much harder to view them as
751 @emph{pure} functions.
754 @node Daemon Offload Setup
755 @subsection Using the Offload Facility
759 When desired, the build daemon can @dfn{offload}
760 derivation builds to other machines
761 running Guix, using the @code{offload} @dfn{build hook}. When that
762 feature is enabled, a list of user-specified build machines is read from
763 @file{/etc/guix/machines.scm}; every time a build is requested, for
764 instance via @code{guix build}, the daemon attempts to offload it to one
765 of the machines that satisfy the constraints of the derivation, in
766 particular its system type---e.g., @file{x86_64-linux}. Missing
767 prerequisites for the build are copied over SSH to the target machine,
768 which then proceeds with the build; upon success the output(s) of the
769 build are copied back to the initial machine.
771 The @file{/etc/guix/machines.scm} file typically looks like this:
775 (name "eightysix.example.org")
776 (system "x86_64-linux")
778 (speed 2.)) ; incredibly fast!
781 (name "meeps.example.org")
782 (system "mips64el-linux")
785 (string-append (getenv "HOME")
786 "/.lsh/identity-for-guix"))))
790 In the example above we specify a list of two build machines, one for
791 the @code{x86_64} architecture and one for the @code{mips64el}
794 In fact, this file is---not surprisingly!---a Scheme file that is
795 evaluated when the @code{offload} hook is started. Its return value
796 must be a list of @code{build-machine} objects. While this example
797 shows a fixed list of build machines, one could imagine, say, using
798 DNS-SD to return a list of potential build machines discovered in the
799 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
800 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
803 @deftp {Data Type} build-machine
804 This data type represents build machines to which the daemon may offload
805 builds. The important fields are:
810 The host name of the remote machine.
813 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
816 The user account to use when connecting to the remote machine over SSH.
817 Note that the SSH key pair must @emph{not} be passphrase-protected, to
818 allow non-interactive logins.
822 A number of optional fields may be specified:
827 Port number of SSH server on the machine (default: 22).
830 The SSH private key file to use when connecting to the machine.
832 Currently offloading uses GNU@tie{}lsh as its SSH client
833 (@pxref{Invoking lsh,,, GNU lsh Manual}). Thus, the key file here must
834 be an lsh key file. This may change in the future, though.
836 @item parallel-builds
837 The number of builds that may run in parallel on the machine (1 by
841 A ``relative speed factor''. The offload scheduler will tend to prefer
842 machines with a higher speed factor.
845 A list of strings denoting specific features supported by the machine.
846 An example is @code{"kvm"} for machines that have the KVM Linux modules
847 and corresponding hardware support. Derivations can request features by
848 name, and they will be scheduled on matching build machines.
853 The @code{guix} command must be in the search path on the build
854 machines, since offloading works by invoking the @code{guix archive} and
855 @code{guix build} commands. In addition, the Guix modules must be in
856 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
857 this is the case by running:
860 lsh build-machine guile -c "'(use-modules (guix config))'"
863 There is one last thing to do once @file{machines.scm} is in place. As
864 explained above, when offloading, files are transferred back and forth
865 between the machine stores. For this to work, you first need to
866 generate a key pair on each machine to allow the daemon to export signed
867 archives of files from the store (@pxref{Invoking guix archive}):
870 # guix archive --generate-key
874 Each build machine must authorize the key of the master machine so that
875 it accepts store items it receives from the master:
878 # guix archive --authorize < master-public-key.txt
882 Likewise, the master machine must authorize the key of each build machine.
884 All the fuss with keys is here to express pairwise mutual trust
885 relations between the master and the build machines. Concretely, when
886 the master receives files from a build machine (and @i{vice versa}), its
887 build daemon can make sure they are genuine, have not been tampered
888 with, and that they are signed by an authorized key.
891 @node Invoking guix-daemon
892 @section Invoking @command{guix-daemon}
894 The @command{guix-daemon} program implements all the functionality to
895 access the store. This includes launching build processes, running the
896 garbage collector, querying the availability of a build result, etc. It
897 is normally run as @code{root} like this:
900 # guix-daemon --build-users-group=guixbuild
904 For details on how to set it up, @pxref{Setting Up the Daemon}.
907 @cindex container, build environment
908 @cindex build environment
909 @cindex reproducible builds
910 By default, @command{guix-daemon} launches build processes under
911 different UIDs, taken from the build group specified with
912 @code{--build-users-group}. In addition, each build process is run in a
913 chroot environment that only contains the subset of the store that the
914 build process depends on, as specified by its derivation
915 (@pxref{Programming Interface, derivation}), plus a set of specific
916 system directories. By default, the latter contains @file{/dev} and
917 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
918 @dfn{container}: in addition to having its own file system tree, it has
919 a separate mount name space, its own PID name space, network name space,
920 etc. This helps achieve reproducible builds (@pxref{Features}).
922 When the daemon performs a build on behalf of the user, it creates a
923 build directory under @file{/tmp} or under the directory specified by
924 its @code{TMPDIR} environment variable; this directory is shared with
925 the container for the duration of the build. Be aware that using a
926 directory other than @file{/tmp} can affect build results---for example,
927 with a longer directory name, a build process that uses Unix-domain
928 sockets might hit the name length limitation for @code{sun_path}, which
929 it would otherwise not hit.
931 The build directory is automatically deleted upon completion, unless the
932 build failed and the client specified @option{--keep-failed}
933 (@pxref{Invoking guix build, @option{--keep-failed}}).
935 The following command-line options are supported:
938 @item --build-users-group=@var{group}
939 Take users from @var{group} to run build processes (@pxref{Setting Up
940 the Daemon, build users}).
942 @item --no-substitutes
944 Do not use substitutes for build products. That is, always build things
945 locally instead of allowing downloads of pre-built binaries
946 (@pxref{Substitutes}).
948 By default substitutes are used, unless the client---such as the
949 @command{guix package} command---is explicitly invoked with
950 @code{--no-substitutes}.
952 When the daemon runs with @code{--no-substitutes}, clients can still
953 explicitly enable substitution @i{via} the @code{set-build-options}
954 remote procedure call (@pxref{The Store}).
956 @item --substitute-urls=@var{urls}
957 @anchor{daemon-substitute-urls}
958 Consider @var{urls} the default whitespace-separated list of substitute
959 source URLs. When this option is omitted,
960 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
961 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
963 This means that substitutes may be downloaded from @var{urls}, as long
964 as they are signed by a trusted signature (@pxref{Substitutes}).
967 @item --no-build-hook
968 Do not use the @dfn{build hook}.
970 The build hook is a helper program that the daemon can start and to
971 which it submits build requests. This mechanism is used to offload
972 builds to other machines (@pxref{Daemon Offload Setup}).
974 @item --cache-failures
975 Cache build failures. By default, only successful builds are cached.
977 When this option is used, @command{guix gc --list-failures} can be used
978 to query the set of store items marked as failed; @command{guix gc
979 --clear-failures} removes store items from the set of cached failures.
980 @xref{Invoking guix gc}.
982 @item --cores=@var{n}
984 Use @var{n} CPU cores to build each derivation; @code{0} means as many
987 The default value is @code{0}, but it may be overridden by clients, such
988 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
991 The effect is to define the @code{NIX_BUILD_CORES} environment variable
992 in the build process, which can then use it to exploit internal
993 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
995 @item --max-jobs=@var{n}
997 Allow at most @var{n} build jobs in parallel. The default value is
998 @code{1}. Setting it to @code{0} means that no builds will be performed
999 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1000 Setup}), or simply fail.
1002 @item --rounds=@var{N}
1003 Build each derivation @var{n} times in a row, and raise an error if
1004 consecutive build results are not bit-for-bit identical. Note that this
1005 setting can be overridden by clients such as @command{guix build}
1006 (@pxref{Invoking guix build}).
1008 When used in conjunction with @option{--keep-failed}, the differing
1009 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1010 This makes it easy to look for differences between the two results.
1013 Produce debugging output.
1015 This is useful to debug daemon start-up issues, but then it may be
1016 overridden by clients, for example the @code{--verbosity} option of
1017 @command{guix build} (@pxref{Invoking guix build}).
1019 @item --chroot-directory=@var{dir}
1020 Add @var{dir} to the build chroot.
1022 Doing this may change the result of build processes---for instance if
1023 they use optional dependencies found in @var{dir} when it is available,
1024 and not otherwise. For that reason, it is not recommended to do so.
1025 Instead, make sure that each derivation declares all the inputs that it
1028 @item --disable-chroot
1029 Disable chroot builds.
1031 Using this option is not recommended since, again, it would allow build
1032 processes to gain access to undeclared dependencies. It is necessary,
1033 though, when @command{guix-daemon} is running under an unprivileged user
1036 @item --disable-log-compression
1037 Disable compression of the build logs.
1039 Unless @code{--lose-logs} is used, all the build logs are kept in the
1040 @var{localstatedir}. To save space, the daemon automatically compresses
1041 them with bzip2 by default. This option disables that.
1043 @item --disable-deduplication
1044 @cindex deduplication
1045 Disable automatic file ``deduplication'' in the store.
1047 By default, files added to the store are automatically ``deduplicated'':
1048 if a newly added file is identical to another one found in the store,
1049 the daemon makes the new file a hard link to the other file. This can
1050 noticeably reduce disk usage, at the expense of slightly increased
1051 input/output load at the end of a build process. This option disables
1054 @item --gc-keep-outputs[=yes|no]
1055 Tell whether the garbage collector (GC) must keep outputs of live
1058 When set to ``yes'', the GC will keep the outputs of any live derivation
1059 available in the store---the @code{.drv} files. The default is ``no'',
1060 meaning that derivation outputs are kept only if they are GC roots.
1062 @item --gc-keep-derivations[=yes|no]
1063 Tell whether the garbage collector (GC) must keep derivations
1064 corresponding to live outputs.
1066 When set to ``yes'', as is the case by default, the GC keeps
1067 derivations---i.e., @code{.drv} files---as long as at least one of their
1068 outputs is live. This allows users to keep track of the origins of
1069 items in their store. Setting it to ``no'' saves a bit of disk space.
1071 Note that when both @code{--gc-keep-derivations} and
1072 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1073 prerequisites (the sources, compiler, libraries, and other build-time
1074 tools) of live objects in the store, regardless of whether these
1075 prerequisites are live. This is convenient for developers since it
1076 saves rebuilds or downloads.
1078 @item --impersonate-linux-2.6
1079 On Linux-based systems, impersonate Linux 2.6. This means that the
1080 kernel's @code{uname} system call will report 2.6 as the release number.
1082 This might be helpful to build programs that (usually wrongfully) depend
1083 on the kernel version number.
1086 Do not keep build logs. By default they are kept under
1087 @code{@var{localstatedir}/guix/log}.
1089 @item --system=@var{system}
1090 Assume @var{system} as the current system type. By default it is the
1091 architecture/kernel pair found at configure time, such as
1092 @code{x86_64-linux}.
1094 @item --listen=@var{socket}
1095 Listen for connections on @var{socket}, the file name of a Unix-domain
1096 socket. The default socket is
1097 @file{@var{localstatedir}/daemon-socket/socket}. This option is only
1098 useful in exceptional circumstances, such as if you need to run several
1099 daemons on the same machine.
1103 @node Application Setup
1104 @section Application Setup
1106 @cindex foreign distro
1107 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1108 so-called @dfn{foreign distro}---a few additional steps are needed to
1109 get everything in place. Here are some of them.
1113 @anchor{locales-and-locpath}
1114 @cindex locales, when not on GuixSD
1116 @vindex GUIX_LOCPATH
1117 Packages installed @i{via} Guix will not use the locale data of the
1118 host system. Instead, you must first install one of the locale packages
1119 available with Guix and then define the @code{GUIX_LOCPATH} environment
1123 $ guix package -i glibc-locales
1124 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1127 Note that the @code{glibc-locales} package contains data for all the
1128 locales supported by the GNU@tie{}libc and weighs in at around
1129 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1130 limited to a few UTF-8 locales.
1132 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1133 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1134 Manual}). There are two important differences though:
1138 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1139 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1140 to make sure the programs of the foreign distro will not end up loading
1141 incompatible locale data.
1144 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1145 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1146 should your Guix profile contain a mixture of programs linked against
1147 different libc version, each libc version will only try to load locale
1148 data in the right format.
1151 This is important because the locale data format used by different libc
1152 versions may be incompatible.
1154 @subsection X11 Fonts
1156 The majority of graphical applications use Fontconfig to locate and
1157 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1158 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1159 by default. Thus, to allow graphical applications installed with Guix
1160 to display fonts, you have to install fonts with Guix as well.
1161 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1162 @code{font-gnu-freefont-ttf}.
1164 To display text written in Chinese languages, Japanese, or Korean in
1165 graphical applications, consider installing
1166 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1167 has multiple outputs, one per language family (@pxref{Packages with
1168 Multiple Outputs}). For instance, the following command installs fonts
1169 for Chinese languages:
1172 guix package -i font-adobe-source-han-sans:cn
1175 @subsection X.509 Certificates
1177 The @code{nss-certs} package provides X.509 certificates, which allow
1178 programs to authenticate Web servers accessed over HTTPS.
1180 When using Guix on a foreign distro, you can install this package and
1181 define the relevant environment variables so that packages know where to
1182 look for certificates. @pxref{X.509 Certificates}, for detailed
1185 @subsection Emacs Packages
1187 When you install Emacs packages with Guix, the elisp files may be placed
1188 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1190 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1191 directory exists because potentially there may exist thousands of Emacs
1192 packages and storing all their files in a single directory may be not
1193 reliable (because of name conflicts). So we think using a separate
1194 directory for each package is a good idea. It is very similar to how
1195 the Emacs package system organizes the file structure (@pxref{Package
1196 Files,,, emacs, The GNU Emacs Manual}).
1198 By default, Emacs (installed with Guix) ``knows'' where these packages
1199 are placed, so you do not need to perform any configuration. If, for
1200 some reason, you want to avoid auto-loading Emacs packages installed
1201 with Guix, you can do so by running Emacs with @code{--no-site-file}
1202 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1206 @c *********************************************************************
1207 @node Package Management
1208 @chapter Package Management
1210 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1211 remove software packages, without having to know about their build
1212 procedures or dependencies. Guix also goes beyond this obvious set of
1215 This chapter describes the main features of Guix, as well as the package
1216 management tools it provides. Two user interfaces are provided for
1217 routine package management tasks: A command-line interface described below
1218 (@pxref{Invoking guix package, @code{guix package}}), as well as a visual user
1219 interface in Emacs described in a subsequent chapter (@pxref{Emacs Interface}).
1222 * Features:: How Guix will make your life brighter.
1223 * Invoking guix package:: Package installation, removal, etc.
1224 * Substitutes:: Downloading pre-built binaries.
1225 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1226 * Invoking guix gc:: Running the garbage collector.
1227 * Invoking guix pull:: Fetching the latest Guix and distribution.
1228 * Invoking guix archive:: Exporting and importing store files.
1234 When using Guix, each package ends up in the @dfn{package store}, in its
1235 own directory---something that resembles
1236 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string
1237 (note that Guix comes with an Emacs extension to shorten those file
1238 names, @pxref{Emacs Prettify}.)
1240 Instead of referring to these directories, users have their own
1241 @dfn{profile}, which points to the packages that they actually want to
1242 use. These profiles are stored within each user's home directory, at
1243 @code{$HOME/.guix-profile}.
1245 For example, @code{alice} installs GCC 4.7.2. As a result,
1246 @file{/home/alice/.guix-profile/bin/gcc} points to
1247 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1248 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1249 simply continues to point to
1250 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1251 coexist on the same system without any interference.
1253 The @command{guix package} command is the central tool to manage
1254 packages (@pxref{Invoking guix package}). It operates on the per-user
1255 profiles, and can be used @emph{with normal user privileges}.
1257 The command provides the obvious install, remove, and upgrade
1258 operations. Each invocation is actually a @emph{transaction}: either
1259 the specified operation succeeds, or nothing happens. Thus, if the
1260 @command{guix package} process is terminated during the transaction,
1261 or if a power outage occurs during the transaction, then the user's
1262 profile remains in its previous state, and remains usable.
1264 In addition, any package transaction may be @emph{rolled back}. So, if,
1265 for example, an upgrade installs a new version of a package that turns
1266 out to have a serious bug, users may roll back to the previous instance
1267 of their profile, which was known to work well. Similarly, the global
1268 system configuration on GuixSD is subject to
1269 transactional upgrades and roll-back
1270 (@pxref{Using the Configuration System}).
1272 All packages in the package store may be @emph{garbage-collected}.
1273 Guix can determine which packages are still referenced by user
1274 profiles, and remove those that are provably no longer referenced
1275 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1276 generations of their profile so that the packages they refer to can be
1279 @cindex reproducibility
1280 @cindex reproducible builds
1281 Finally, Guix takes a @dfn{purely functional} approach to package
1282 management, as described in the introduction (@pxref{Introduction}).
1283 Each @file{/gnu/store} package directory name contains a hash of all the
1284 inputs that were used to build that package---compiler, libraries, build
1285 scripts, etc. This direct correspondence allows users to make sure a
1286 given package installation matches the current state of their
1287 distribution. It also helps maximize @dfn{build reproducibility}:
1288 thanks to the isolated build environments that are used, a given build
1289 is likely to yield bit-identical files when performed on different
1290 machines (@pxref{Invoking guix-daemon, container}).
1293 This foundation allows Guix to support @dfn{transparent binary/source
1294 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1295 available from an external source---a @dfn{substitute}, Guix just
1296 downloads it and unpacks it;
1297 otherwise, it builds the package from source, locally
1298 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1299 reproducible, users do not have to trust servers that provide
1300 substitutes: they can force a local build and @emph{challenge} providers
1301 (@pxref{Invoking guix challenge}).
1303 Control over the build environment is a feature that is also useful for
1304 developers. The @command{guix environment} command allows developers of
1305 a package to quickly set up the right development environment for their
1306 package, without having to manually install the dependencies of the
1307 package into their profile (@pxref{Invoking guix environment}).
1309 @node Invoking guix package
1310 @section Invoking @command{guix package}
1312 The @command{guix package} command is the tool that allows users to
1313 install, upgrade, and remove packages, as well as rolling back to
1314 previous configurations. It operates only on the user's own profile,
1315 and works with normal user privileges (@pxref{Features}). Its syntax
1319 guix package @var{options}
1322 Primarily, @var{options} specifies the operations to be performed during
1323 the transaction. Upon completion, a new profile is created, but
1324 previous @dfn{generations} of the profile remain available, should the user
1327 For example, to remove @code{lua} and install @code{guile} and
1328 @code{guile-cairo} in a single transaction:
1331 guix package -r lua -i guile guile-cairo
1334 @command{guix package} also supports a @dfn{declarative approach}
1335 whereby the user specifies the exact set of packages to be available and
1336 passes it @i{via} the @option{--manifest} option
1337 (@pxref{profile-manifest, @option{--manifest}}).
1339 For each user, a symlink to the user's default profile is automatically
1340 created in @file{$HOME/.guix-profile}. This symlink always points to the
1341 current generation of the user's default profile. Thus, users can add
1342 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1343 variable, and so on.
1344 @cindex search paths
1345 If you are not using the Guix System Distribution, consider adding the
1346 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1347 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1348 shells get all the right environment variable definitions:
1351 GUIX_PROFILE="$HOME/.guix-profile" \
1352 source "$HOME/.guix-profile/etc/profile"
1355 In a multi-user setup, user profiles are stored in a place registered as
1356 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1357 to (@pxref{Invoking guix gc}). That directory is normally
1358 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1359 @var{localstatedir} is the value passed to @code{configure} as
1360 @code{--localstatedir}, and @var{user} is the user name. The
1361 @file{per-user} directory is created when @command{guix-daemon} is
1362 started, and the @var{user} sub-directory is created by @command{guix
1365 The @var{options} can be among the following:
1369 @item --install=@var{package} @dots{}
1370 @itemx -i @var{package} @dots{}
1371 Install the specified @var{package}s.
1373 Each @var{package} may specify either a simple package name, such as
1374 @code{guile}, or a package name followed by an at-sign and version number,
1375 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1376 case, the newest version prefixed by @code{1.8} is selected.)
1378 If no version number is specified, the
1379 newest available version will be selected. In addition, @var{package}
1380 may contain a colon, followed by the name of one of the outputs of the
1381 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1382 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1383 name (and optionally version) are searched for among the GNU
1384 distribution modules (@pxref{Package Modules}).
1386 @cindex propagated inputs
1387 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1388 that automatically get installed along with the required package
1389 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1390 @code{package} objects}, for information about propagated inputs in
1391 package definitions).
1393 @anchor{package-cmd-propagated-inputs}
1394 An example is the GNU MPC library: its C header files refer to those of
1395 the GNU MPFR library, which in turn refer to those of the GMP library.
1396 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1397 in the profile; removing MPC also removes MPFR and GMP---unless they had
1398 also been explicitly installed by the user.
1400 Besides, packages sometimes rely on the definition of environment
1401 variables for their search paths (see explanation of
1402 @code{--search-paths} below). Any missing or possibly incorrect
1403 environment variable definitions are reported here.
1405 @item --install-from-expression=@var{exp}
1407 Install the package @var{exp} evaluates to.
1409 @var{exp} must be a Scheme expression that evaluates to a
1410 @code{<package>} object. This option is notably useful to disambiguate
1411 between same-named variants of a package, with expressions such as
1412 @code{(@@ (gnu packages base) guile-final)}.
1414 Note that this option installs the first output of the specified
1415 package, which may be insufficient when needing a specific output of a
1416 multiple-output package.
1418 @item --install-from-file=@var{file}
1419 @itemx -f @var{file}
1420 Install the package that the code within @var{file} evaluates to.
1422 As an example, @var{file} might contain a definition like this
1423 (@pxref{Defining Packages}):
1426 @verbatiminclude package-hello.scm
1429 Developers may find it useful to include such a @file{guix.scm} file
1430 in the root of their project source tree that can be used to test
1431 development snapshots and create reproducible development environments
1432 (@pxref{Invoking guix environment}).
1434 @item --remove=@var{package} @dots{}
1435 @itemx -r @var{package} @dots{}
1436 Remove the specified @var{package}s.
1438 As for @code{--install}, each @var{package} may specify a version number
1439 and/or output name in addition to the package name. For instance,
1440 @code{-r glibc:debug} would remove the @code{debug} output of
1443 @item --upgrade[=@var{regexp} @dots{}]
1444 @itemx -u [@var{regexp} @dots{}]
1445 Upgrade all the installed packages. If one or more @var{regexp}s are
1446 specified, upgrade only installed packages whose name matches a
1447 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1449 Note that this upgrades package to the latest version of packages found
1450 in the distribution currently installed. To update your distribution,
1451 you should regularly run @command{guix pull} (@pxref{Invoking guix
1454 @item --do-not-upgrade[=@var{regexp} @dots{}]
1455 When used together with the @code{--upgrade} option, do @emph{not}
1456 upgrade any packages whose name matches a @var{regexp}. For example, to
1457 upgrade all packages in the current profile except those containing the
1458 substring ``emacs'':
1461 $ guix package --upgrade . --do-not-upgrade emacs
1464 @item @anchor{profile-manifest}--manifest=@var{file}
1465 @itemx -m @var{file}
1466 @cindex profile declaration
1467 @cindex profile manifest
1468 Create a new generation of the profile from the manifest object
1469 returned by the Scheme code in @var{file}.
1471 This allows you to @emph{declare} the profile's contents rather than
1472 constructing it through a sequence of @code{--install} and similar
1473 commands. The advantage is that @var{file} can be put under version
1474 control, copied to different machines to reproduce the same profile, and
1477 @c FIXME: Add reference to (guix profile) documentation when available.
1478 @var{file} must return a @dfn{manifest} object, which is roughly a list
1481 @findex packages->manifest
1483 (use-package-modules guile emacs)
1488 ;; Use a specific package output.
1489 (list guile-2.0 "debug")))
1493 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1494 the last transaction.
1496 When combined with options such as @code{--install}, roll back occurs
1497 before any other actions.
1499 When rolling back from the first generation that actually contains
1500 installed packages, the profile is made to point to the @dfn{zeroth
1501 generation}, which contains no files apart from its own metadata.
1503 After having rolled back, installing, removing, or upgrading packages
1504 overwrites previous future generations. Thus, the history of the
1505 generations in a profile is always linear.
1507 @item --switch-generation=@var{pattern}
1508 @itemx -S @var{pattern}
1509 Switch to a particular generation defined by @var{pattern}.
1511 @var{pattern} may be either a generation number or a number prefixed
1512 with ``+'' or ``-''. The latter means: move forward/backward by a
1513 specified number of generations. For example, if you want to return to
1514 the latest generation after @code{--roll-back}, use
1515 @code{--switch-generation=+1}.
1517 The difference between @code{--roll-back} and
1518 @code{--switch-generation=-1} is that @code{--switch-generation} will
1519 not make a zeroth generation, so if a specified generation does not
1520 exist, the current generation will not be changed.
1522 @item --search-paths[=@var{kind}]
1523 @cindex search paths
1524 Report environment variable definitions, in Bash syntax, that may be
1525 needed in order to use the set of installed packages. These environment
1526 variables are used to specify @dfn{search paths} for files used by some
1527 of the installed packages.
1529 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1530 environment variables to be defined so it can look for headers and
1531 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1532 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1533 library are installed in the profile, then @code{--search-paths} will
1534 suggest setting these variables to @code{@var{profile}/include} and
1535 @code{@var{profile}/lib}, respectively.
1537 The typical use case is to define these environment variables in the
1541 $ eval `guix package --search-paths`
1544 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1545 meaning that the returned environment variable definitions will either
1546 be exact settings, or prefixes or suffixes of the current value of these
1547 variables. When omitted, @var{kind} defaults to @code{exact}.
1549 This option can also be used to compute the @emph{combined} search paths
1550 of several profiles. Consider this example:
1553 $ guix package -p foo -i guile
1554 $ guix package -p bar -i guile-json
1555 $ guix package -p foo -p bar --search-paths
1558 The last command above reports about the @code{GUILE_LOAD_PATH}
1559 variable, even though, taken individually, neither @file{foo} nor
1560 @file{bar} would lead to that recommendation.
1563 @item --profile=@var{profile}
1564 @itemx -p @var{profile}
1565 Use @var{profile} instead of the user's default profile.
1568 Produce verbose output. In particular, emit the build log of the
1569 environment on the standard error port.
1572 Use the bootstrap Guile to build the profile. This option is only
1573 useful to distribution developers.
1577 In addition to these actions, @command{guix package} supports the
1578 following options to query the current state of a profile, or the
1579 availability of packages:
1583 @item --search=@var{regexp}
1584 @itemx -s @var{regexp}
1585 @cindex searching for packages
1586 List the available packages whose name, synopsis, or description matches
1587 @var{regexp}. Print all the metadata of matching packages in
1588 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1589 GNU recutils manual}).
1591 This allows specific fields to be extracted using the @command{recsel}
1592 command, for instance:
1595 $ guix package -s malloc | recsel -p name,version
1603 Similarly, to show the name of all the packages available under the
1604 terms of the GNU@tie{}LGPL version 3:
1607 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1614 It is also possible to refine search results using several @code{-s}
1615 flags. For example, the following command returns a list of board
1619 $ guix package -s '\<board\>' -s game | recsel -p name
1624 If we were to omit @code{-s game}, we would also get software packages
1625 that deal with printed circuit boards; removing the angle brackets
1626 around @code{board} would further add packages that have to do with
1629 And now for a more elaborate example. The following command searches
1630 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1631 libraries, and prints the name and synopsis of the matching packages:
1634 $ guix package -s crypto -s library | \
1635 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1639 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1640 information on @dfn{selection expressions} for @code{recsel -e}.
1642 @item --show=@var{package}
1643 Show details about @var{package}, taken from the list of available packages, in
1644 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1648 $ guix package --show=python | recsel -p name,version
1656 You may also specify the full name of a package to only get details about a
1657 specific version of it:
1659 $ guix package --show=python-3.3.5 | recsel -p name,version
1666 @item --list-installed[=@var{regexp}]
1667 @itemx -I [@var{regexp}]
1668 List the currently installed packages in the specified profile, with the
1669 most recently installed packages shown last. When @var{regexp} is
1670 specified, list only installed packages whose name matches @var{regexp}.
1672 For each installed package, print the following items, separated by
1673 tabs: the package name, its version string, the part of the package that
1674 is installed (for instance, @code{out} for the default output,
1675 @code{include} for its headers, etc.), and the path of this package in
1678 @item --list-available[=@var{regexp}]
1679 @itemx -A [@var{regexp}]
1680 List packages currently available in the distribution for this system
1681 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
1682 installed packages whose name matches @var{regexp}.
1684 For each package, print the following items separated by tabs: its name,
1685 its version string, the parts of the package (@pxref{Packages with
1686 Multiple Outputs}), and the source location of its definition.
1688 @item --list-generations[=@var{pattern}]
1689 @itemx -l [@var{pattern}]
1690 Return a list of generations along with their creation dates; for each
1691 generation, show the installed packages, with the most recently
1692 installed packages shown last. Note that the zeroth generation is never
1695 For each installed package, print the following items, separated by
1696 tabs: the name of a package, its version string, the part of the package
1697 that is installed (@pxref{Packages with Multiple Outputs}), and the
1698 location of this package in the store.
1700 When @var{pattern} is used, the command returns only matching
1701 generations. Valid patterns include:
1704 @item @emph{Integers and comma-separated integers}. Both patterns denote
1705 generation numbers. For instance, @code{--list-generations=1} returns
1708 And @code{--list-generations=1,8,2} outputs three generations in the
1709 specified order. Neither spaces nor trailing commas are allowed.
1711 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
1712 specified generations and everything in between. Note that the start of
1713 a range must be smaller than its end.
1715 It is also possible to omit the endpoint. For example,
1716 @code{--list-generations=2..}, returns all generations starting from the
1719 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
1720 or months by passing an integer along with the first letter of the
1721 duration. For example, @code{--list-generations=20d} lists generations
1722 that are up to 20 days old.
1725 @item --delete-generations[=@var{pattern}]
1726 @itemx -d [@var{pattern}]
1727 When @var{pattern} is omitted, delete all generations except the current
1730 This command accepts the same patterns as @option{--list-generations}.
1731 When @var{pattern} is specified, delete the matching generations. When
1732 @var{pattern} specifies a duration, generations @emph{older} than the
1733 specified duration match. For instance, @code{--delete-generations=1m}
1734 deletes generations that are more than one month old.
1736 If the current generation matches, it is @emph{not} deleted. Also, the
1737 zeroth generation is never deleted.
1739 Note that deleting generations prevents rolling back to them.
1740 Consequently, this command must be used with care.
1744 Finally, since @command{guix package} may actually start build
1745 processes, it supports all the common build options (@pxref{Common Build
1746 Options}). It also supports package transformation options, such as
1747 @option{--with-source} (@pxref{Package Transformation Options}).
1748 However, note that package transformations are lost when upgrading; to
1749 preserve transformations across upgrades, you should define your own
1750 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
1751 (@pxref{Defining Packages}).
1755 @section Substitutes
1758 @cindex pre-built binaries
1759 Guix supports transparent source/binary deployment, which means that it
1760 can either build things locally, or download pre-built items from a
1761 server. We call these pre-built items @dfn{substitutes}---they are
1762 substitutes for local build results. In many cases, downloading a
1763 substitute is much faster than building things locally.
1765 Substitutes can be anything resulting from a derivation build
1766 (@pxref{Derivations}). Of course, in the common case, they are
1767 pre-built package binaries, but source tarballs, for instance, which
1768 also result from derivation builds, can be available as substitutes.
1770 The @code{hydra.gnu.org} server is a front-end to a build farm that
1771 builds packages from the GNU distribution continuously for some
1772 architectures, and makes them available as substitutes (@pxref{Emacs
1773 Hydra}, for information on how to query the continuous integration
1774 server). This is the
1775 default source of substitutes; it can be overridden by passing the
1776 @option{--substitute-urls} option either to @command{guix-daemon}
1777 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
1778 or to client tools such as @command{guix package}
1779 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
1782 Substitute URLs can be either HTTP or HTTPS@footnote{For HTTPS access,
1783 the Guile bindings of GnuTLS must be installed. @xref{Requirements}.}
1784 HTTPS is recommended because communications are encrypted; conversely,
1785 using HTTP makes all communications visible to an eavesdropper, who
1786 could use the information gathered to determine, for instance, whether
1787 your system has unpatched security vulnerabilities.
1790 @cindex digital signatures
1791 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
1793 must add its public key to the access control list (ACL) of archive
1794 imports, using the @command{guix archive} command (@pxref{Invoking guix
1795 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
1796 be compromised and to serve genuine substitutes.
1798 This public key is installed along with Guix, in
1799 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
1800 the installation prefix of Guix. If you installed Guix from source,
1801 make sure you checked the GPG signature of
1802 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
1803 Then, you can run something like this:
1806 # guix archive --authorize < hydra.gnu.org.pub
1809 Once this is in place, the output of a command like @code{guix build}
1810 should change from something like:
1813 $ guix build emacs --dry-run
1814 The following derivations would be built:
1815 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
1816 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
1817 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
1818 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
1826 $ guix build emacs --dry-run
1827 The following files would be downloaded:
1828 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
1829 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
1830 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
1831 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
1836 This indicates that substitutes from @code{hydra.gnu.org} are usable and
1837 will be downloaded, when possible, for future builds.
1839 Guix ignores substitutes that are not signed, or that are not signed by
1840 one of the keys listed in the ACL. It also detects and raises an error
1841 when attempting to use a substitute that has been tampered with.
1844 Substitutes are downloaded over HTTP or HTTPS.
1845 The @code{http_proxy} environment
1846 variable can be set in the environment of @command{guix-daemon} and is
1847 honored for downloads of substitutes. Note that the value of
1848 @code{http_proxy} in the environment where @command{guix build},
1849 @command{guix package}, and other client commands are run has
1850 @emph{absolutely no effect}.
1852 When using HTTPS, the server's X.509 certificate is @emph{not} validated
1853 (in other words, the server is not authenticated), contrary to what
1854 HTTPS clients such as Web browsers usually do. This is because Guix
1855 authenticates substitute information itself, as explained above, which
1856 is what we care about (whereas X.509 certificates are about
1857 authenticating bindings between domain names and public keys.)
1859 The substitute mechanism can be disabled globally by running
1860 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
1861 guix-daemon}). It can also be disabled temporarily by passing the
1862 @code{--no-substitutes} option to @command{guix package}, @command{guix
1863 build}, and other command-line tools.
1866 @unnumberedsubsec On Trusting Binaries
1868 Today, each individual's control over their own computing is at the
1869 mercy of institutions, corporations, and groups with enough power and
1870 determination to subvert the computing infrastructure and exploit its
1871 weaknesses. While using @code{hydra.gnu.org} substitutes can be
1872 convenient, we encourage users to also build on their own, or even run
1873 their own build farm, such that @code{hydra.gnu.org} is less of an
1874 interesting target. One way to help is by publishing the software you
1875 build using @command{guix publish} so that others have one more choice
1876 of server to download substitutes from (@pxref{Invoking guix publish}).
1878 Guix has the foundations to maximize build reproducibility
1879 (@pxref{Features}). In most cases, independent builds of a given
1880 package or derivation should yield bit-identical results. Thus, through
1881 a diverse set of independent package builds, we can strengthen the
1882 integrity of our systems. The @command{guix challenge} command aims to
1883 help users assess substitute servers, and to assist developers in
1884 finding out about non-deterministic package builds (@pxref{Invoking guix
1885 challenge}). Similarly, the @option{--check} option of @command{guix
1886 build} allows users to check whether previously-installed substitutes
1887 are genuine by rebuilding them locally (@pxref{build-check,
1888 @command{guix build --check}}).
1890 In the future, we want Guix to have support to publish and retrieve
1891 binaries to/from other users, in a peer-to-peer fashion. If you would
1892 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
1895 @node Packages with Multiple Outputs
1896 @section Packages with Multiple Outputs
1898 @cindex multiple-output packages
1899 @cindex package outputs
1901 Often, packages defined in Guix have a single @dfn{output}---i.e., the
1902 source package leads to exactly one directory in the store. When running
1903 @command{guix package -i glibc}, one installs the default output of the
1904 GNU libc package; the default output is called @code{out}, but its name
1905 can be omitted as shown in this command. In this particular case, the
1906 default output of @code{glibc} contains all the C header files, shared
1907 libraries, static libraries, Info documentation, and other supporting
1910 Sometimes it is more appropriate to separate the various types of files
1911 produced from a single source package into separate outputs. For
1912 instance, the GLib C library (used by GTK+ and related packages)
1913 installs more than 20 MiB of reference documentation as HTML pages.
1914 To save space for users who do not need it, the documentation goes to a
1915 separate output, called @code{doc}. To install the main GLib output,
1916 which contains everything but the documentation, one would run:
1919 guix package -i glib
1922 The command to install its documentation is:
1925 guix package -i glib:doc
1928 Some packages install programs with different ``dependency footprints''.
1929 For instance, the WordNet package installs both command-line tools and
1930 graphical user interfaces (GUIs). The former depend solely on the C
1931 library, whereas the latter depend on Tcl/Tk and the underlying X
1932 libraries. In this case, we leave the command-line tools in the default
1933 output, whereas the GUIs are in a separate output. This allows users
1934 who do not need the GUIs to save space. The @command{guix size} command
1935 can help find out about such situations (@pxref{Invoking guix size}).
1936 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
1938 There are several such multiple-output packages in the GNU distribution.
1939 Other conventional output names include @code{lib} for libraries and
1940 possibly header files, @code{bin} for stand-alone programs, and
1941 @code{debug} for debugging information (@pxref{Installing Debugging
1942 Files}). The outputs of a packages are listed in the third column of
1943 the output of @command{guix package --list-available} (@pxref{Invoking
1947 @node Invoking guix gc
1948 @section Invoking @command{guix gc}
1950 @cindex garbage collector
1951 Packages that are installed, but not used, may be @dfn{garbage-collected}.
1952 The @command{guix gc} command allows users to explicitly run the garbage
1953 collector to reclaim space from the @file{/gnu/store} directory. It is
1954 the @emph{only} way to remove files from @file{/gnu/store}---removing
1955 files or directories manually may break it beyond repair!
1957 The garbage collector has a set of known @dfn{roots}: any file under
1958 @file{/gnu/store} reachable from a root is considered @dfn{live} and
1959 cannot be deleted; any other file is considered @dfn{dead} and may be
1960 deleted. The set of garbage collector roots includes default user
1961 profiles, and may be augmented with @command{guix build --root}, for
1962 example (@pxref{Invoking guix build}).
1964 Prior to running @code{guix gc --collect-garbage} to make space, it is
1965 often useful to remove old generations from user profiles; that way, old
1966 package builds referenced by those generations can be reclaimed. This
1967 is achieved by running @code{guix package --delete-generations}
1968 (@pxref{Invoking guix package}).
1970 The @command{guix gc} command has three modes of operation: it can be
1971 used to garbage-collect any dead files (the default), to delete specific
1972 files (the @code{--delete} option), to print garbage-collector
1973 information, or for more advanced queries. The garbage collection
1974 options are as follows:
1977 @item --collect-garbage[=@var{min}]
1978 @itemx -C [@var{min}]
1979 Collect garbage---i.e., unreachable @file{/gnu/store} files and
1980 sub-directories. This is the default operation when no option is
1983 When @var{min} is given, stop once @var{min} bytes have been collected.
1984 @var{min} may be a number of bytes, or it may include a unit as a
1985 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
1986 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
1988 When @var{min} is omitted, collect all the garbage.
1990 @item --free-space=@var{free}
1991 @itemx -F @var{free}
1992 Collect garbage until @var{free} space is available under
1993 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
1994 as @code{500MiB}, as described above.
1996 When @var{free} or more is already available in @file{/gnu/store}, do
1997 nothing and exit immediately.
2001 Attempt to delete all the store files and directories specified as
2002 arguments. This fails if some of the files are not in the store, or if
2003 they are still live.
2005 @item --list-failures
2006 List store items corresponding to cached build failures.
2008 This prints nothing unless the daemon was started with
2009 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2010 @option{--cache-failures}}).
2012 @item --clear-failures
2013 Remove the specified store items from the failed-build cache.
2015 Again, this option only makes sense when the daemon is started with
2016 @option{--cache-failures}. Otherwise, it does nothing.
2019 Show the list of dead files and directories still present in the
2020 store---i.e., files and directories no longer reachable from any root.
2023 Show the list of live store files and directories.
2027 In addition, the references among existing store files can be queried:
2033 List the references (respectively, the referrers) of store files given
2039 List the requisites of the store files passed as arguments. Requisites
2040 include the store files themselves, their references, and the references
2041 of these, recursively. In other words, the returned list is the
2042 @dfn{transitive closure} of the store files.
2044 @xref{Invoking guix size}, for a tool to profile the size of the closure
2045 of an element. @xref{Invoking guix graph}, for a tool to visualize
2046 the graph of references.
2050 Lastly, the following options allow you to check the integrity of the
2051 store and to control disk usage.
2055 @item --verify[=@var{options}]
2056 @cindex integrity, of the store
2057 @cindex integrity checking
2058 Verify the integrity of the store.
2060 By default, make sure that all the store items marked as valid in the
2061 database of the daemon actually exist in @file{/gnu/store}.
2063 When provided, @var{options} must be a comma-separated list containing one
2064 or more of @code{contents} and @code{repair}.
2066 When passing @option{--verify=contents}, the daemon computse the
2067 content hash of each store item and compares it against its hash in the
2068 database. Hash mismatches are reported as data corruptions. Because it
2069 traverses @emph{all the files in the store}, this command can take a
2070 long time, especially on systems with a slow disk drive.
2072 @cindex repairing the store
2073 Using @option{--verify=repair} or @option{--verify=contents,repair}
2074 causes the daemon to try to repair corrupt store items by fetching
2075 substitutes for them (@pxref{Substitutes}). Because repairing is not
2076 atomic, and thus potentially dangerous, it is available only to the
2077 system administrator.
2080 @cindex deduplication
2081 Optimize the store by hard-linking identical files---this is
2082 @dfn{deduplication}.
2084 The daemon performs deduplication after each successful build or archive
2085 import, unless it was started with @code{--disable-deduplication}
2086 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2087 this option is primarily useful when the daemon was running with
2088 @code{--disable-deduplication}.
2092 @node Invoking guix pull
2093 @section Invoking @command{guix pull}
2095 Packages are installed or upgraded to the latest version available in
2096 the distribution currently available on your local machine. To update
2097 that distribution, along with the Guix tools, you must run @command{guix
2098 pull}: the command downloads the latest Guix source code and package
2099 descriptions, and deploys it.
2101 On completion, @command{guix package} will use packages and package
2102 versions from this just-retrieved copy of Guix. Not only that, but all
2103 the Guix commands and Scheme modules will also be taken from that latest
2104 version. New @command{guix} sub-commands added by the update also
2107 Any user can update their Guix copy using @command{guix pull}, and the
2108 effect is limited to the user who run @command{guix pull}. For
2109 instance, when user @code{root} runs @command{guix pull}, this has no
2110 effect on the version of Guix that user @code{alice} sees, and vice
2111 versa@footnote{Under the hood, @command{guix pull} updates the
2112 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2113 and the @command{guix} command loads code from there.}.
2115 The @command{guix pull} command is usually invoked with no arguments,
2116 but it supports the following options:
2120 Produce verbose output, writing build logs to the standard error output.
2122 @item --url=@var{url}
2123 Download the source tarball of Guix from @var{url}.
2125 By default, the tarball is taken from its canonical address at
2126 @code{gnu.org}, for the stable branch of Guix.
2129 Use the bootstrap Guile to build the latest Guix. This option is only
2130 useful to Guix developers.
2134 @node Invoking guix archive
2135 @section Invoking @command{guix archive}
2137 The @command{guix archive} command allows users to @dfn{export} files
2138 from the store into a single archive, and to later @dfn{import} them.
2139 In particular, it allows store files to be transferred from one machine
2140 to the store on another machine.
2142 To export store files as an archive to standard output, run:
2145 guix archive --export @var{options} @var{specifications}...
2148 @var{specifications} may be either store file names or package
2149 specifications, as for @command{guix package} (@pxref{Invoking guix
2150 package}). For instance, the following command creates an archive
2151 containing the @code{gui} output of the @code{git} package and the main
2152 output of @code{emacs}:
2155 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2158 If the specified packages are not built yet, @command{guix archive}
2159 automatically builds them. The build process may be controlled with the
2160 common build options (@pxref{Common Build Options}).
2162 To transfer the @code{emacs} package to a machine connected over SSH,
2166 guix archive --export -r emacs | ssh the-machine guix archive --import
2170 Similarly, a complete user profile may be transferred from one machine
2171 to another like this:
2174 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2175 ssh the-machine guix-archive --import
2179 However, note that, in both examples, all of @code{emacs} and the
2180 profile as well as all of their dependencies are transferred (due to
2181 @code{-r}), regardless of what is already available in the store on the
2182 target machine. The @code{--missing} option can help figure out which
2183 items are missing from the target store.
2185 Archives are stored in the ``Nix archive'' or ``Nar'' format, which is
2186 comparable in spirit to `tar', but with a few noteworthy differences
2187 that make it more appropriate for our purposes. First, rather than
2188 recording all Unix metadata for each file, the Nar format only mentions
2189 the file type (regular, directory, or symbolic link); Unix permissions
2190 and owner/group are dismissed. Second, the order in which directory
2191 entries are stored always follows the order of file names according to
2192 the C locale collation order. This makes archive production fully
2195 When exporting, the daemon digitally signs the contents of the archive,
2196 and that digital signature is appended. When importing, the daemon
2197 verifies the signature and rejects the import in case of an invalid
2198 signature or if the signing key is not authorized.
2199 @c FIXME: Add xref to daemon doc about signatures.
2201 The main options are:
2205 Export the specified store files or packages (see below.) Write the
2206 resulting archive to the standard output.
2208 Dependencies are @emph{not} included in the output, unless
2209 @code{--recursive} is passed.
2213 When combined with @code{--export}, this instructs @command{guix
2214 archive} to include dependencies of the given items in the archive.
2215 Thus, the resulting archive is self-contained: it contains the closure
2216 of the exported store items.
2219 Read an archive from the standard input, and import the files listed
2220 therein into the store. Abort if the archive has an invalid digital
2221 signature, or if it is signed by a public key not among the authorized
2222 keys (see @code{--authorize} below.)
2225 Read a list of store file names from the standard input, one per line,
2226 and write on the standard output the subset of these files missing from
2229 @item --generate-key[=@var{parameters}]
2230 @cindex signing, archives
2231 Generate a new key pair for the daemon. This is a prerequisite before
2232 archives can be exported with @code{--export}. Note that this operation
2233 usually takes time, because it needs to gather enough entropy to
2234 generate the key pair.
2236 The generated key pair is typically stored under @file{/etc/guix}, in
2237 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2238 key, which must be kept secret.) When @var{parameters} is omitted,
2239 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2240 versions before 1.6.0, it is a 4096-bit RSA key.
2241 Alternatively, @var{parameters} can specify
2242 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2243 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2244 Libgcrypt Reference Manual}).
2247 @cindex authorizing, archives
2248 Authorize imports signed by the public key passed on standard input.
2249 The public key must be in ``s-expression advanced format''---i.e., the
2250 same format as the @file{signing-key.pub} file.
2252 The list of authorized keys is kept in the human-editable file
2253 @file{/etc/guix/acl}. The file contains
2254 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2255 s-expressions''} and is structured as an access-control list in the
2256 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2259 @item --extract=@var{directory}
2260 @itemx -x @var{directory}
2261 Read a single-item archive as served by substitute servers
2262 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2263 low-level operation needed in only very narrow use cases; see below.
2265 For example, the following command extracts the substitute for Emacs
2266 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2270 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2271 | bunzip2 | guix archive -x /tmp/emacs
2274 Single-item archives are different from multiple-item archives produced
2275 by @command{guix archive --export}; they contain a single store item,
2276 and they do @emph{not} embed a signature. Thus this operation does
2277 @emph{no} signature verification and its output should be considered
2280 The primary purpose of this operation is to facilitate inspection of
2281 archive contents coming from possibly untrusted substitute servers.
2285 @c *********************************************************************
2288 @c *********************************************************************
2289 @node Programming Interface
2290 @chapter Programming Interface
2292 GNU Guix provides several Scheme programming interfaces (APIs) to
2293 define, build, and query packages. The first interface allows users to
2294 write high-level package definitions. These definitions refer to
2295 familiar packaging concepts, such as the name and version of a package,
2296 its build system, and its dependencies. These definitions can then be
2297 turned into concrete build actions.
2299 Build actions are performed by the Guix daemon, on behalf of users. In a
2300 standard setup, the daemon has write access to the store---the
2301 @file{/gnu/store} directory---whereas users do not. The recommended
2302 setup also has the daemon perform builds in chroots, under a specific
2303 build users, to minimize interference with the rest of the system.
2306 Lower-level APIs are available to interact with the daemon and the
2307 store. To instruct the daemon to perform a build action, users actually
2308 provide it with a @dfn{derivation}. A derivation is a low-level
2309 representation of the build actions to be taken, and the environment in
2310 which they should occur---derivations are to package definitions what
2311 assembly is to C programs. The term ``derivation'' comes from the fact
2312 that build results @emph{derive} from them.
2314 This chapter describes all these APIs in turn, starting from high-level
2315 package definitions.
2318 * Defining Packages:: Defining new packages.
2319 * Build Systems:: Specifying how packages are built.
2320 * The Store:: Manipulating the package store.
2321 * Derivations:: Low-level interface to package derivations.
2322 * The Store Monad:: Purely functional interface to the store.
2323 * G-Expressions:: Manipulating build expressions.
2326 @node Defining Packages
2327 @section Defining Packages
2329 The high-level interface to package definitions is implemented in the
2330 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2331 example, the package definition, or @dfn{recipe}, for the GNU Hello
2332 package looks like this:
2335 (define-module (gnu packages hello)
2336 #:use-module (guix packages)
2337 #:use-module (guix download)
2338 #:use-module (guix build-system gnu)
2339 #:use-module (guix licenses)
2340 #:use-module (gnu packages gawk))
2342 (define-public hello
2348 (uri (string-append "mirror://gnu/hello/hello-" version
2352 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2353 (build-system gnu-build-system)
2354 (arguments `(#:configure-flags '("--enable-silent-rules")))
2355 (inputs `(("gawk" ,gawk)))
2356 (synopsis "Hello, GNU world: An example GNU package")
2357 (description "Guess what GNU Hello prints!")
2358 (home-page "http://www.gnu.org/software/hello/")
2363 Without being a Scheme expert, the reader may have guessed the meaning
2364 of the various fields here. This expression binds the variable
2365 @code{hello} to a @code{<package>} object, which is essentially a record
2366 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2367 This package object can be inspected using procedures found in the
2368 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2369 returns---surprise!---@code{"hello"}.
2371 With luck, you may be able to import part or all of the definition of
2372 the package you are interested in from another repository, using the
2373 @code{guix import} command (@pxref{Invoking guix import}).
2375 In the example above, @var{hello} is defined in a module of its own,
2376 @code{(gnu packages hello)}. Technically, this is not strictly
2377 necessary, but it is convenient to do so: all the packages defined in
2378 modules under @code{(gnu packages @dots{})} are automatically known to
2379 the command-line tools (@pxref{Package Modules}).
2381 There are a few points worth noting in the above package definition:
2385 The @code{source} field of the package is an @code{<origin>} object
2386 (@pxref{origin Reference}, for the complete reference).
2387 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2388 meaning that the source is a file to be downloaded over FTP or HTTP.
2390 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2391 the GNU mirrors defined in @code{(guix download)}.
2393 The @code{sha256} field specifies the expected SHA256 hash of the file
2394 being downloaded. It is mandatory, and allows Guix to check the
2395 integrity of the file. The @code{(base32 @dots{})} form introduces the
2396 base32 representation of the hash. You can obtain this information with
2397 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2398 hash} (@pxref{Invoking guix hash}).
2401 When needed, the @code{origin} form can also have a @code{patches} field
2402 listing patches to be applied, and a @code{snippet} field giving a
2403 Scheme expression to modify the source code.
2406 @cindex GNU Build System
2407 The @code{build-system} field specifies the procedure to build the
2408 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2409 represents the familiar GNU Build System, where packages may be
2410 configured, built, and installed with the usual @code{./configure &&
2411 make && make check && make install} command sequence.
2414 The @code{arguments} field specifies options for the build system
2415 (@pxref{Build Systems}). Here it is interpreted by
2416 @var{gnu-build-system} as a request run @file{configure} with the
2417 @code{--enable-silent-rules} flag.
2420 The @code{inputs} field specifies inputs to the build process---i.e.,
2421 build-time or run-time dependencies of the package. Here, we define an
2422 input called @code{"gawk"} whose value is that of the @var{gawk}
2423 variable; @var{gawk} is itself bound to a @code{<package>} object.
2425 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2426 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2427 of ensuring that they are present (@pxref{Build Systems}).
2429 However, any other dependencies need to be specified in the
2430 @code{inputs} field. Any dependency not specified here will simply be
2431 unavailable to the build process, possibly leading to a build failure.
2434 @xref{package Reference}, for a full description of possible fields.
2436 Once a package definition is in place, the
2437 package may actually be built using the @code{guix build} command-line
2438 tool (@pxref{Invoking guix build}). You can easily jump back to the
2439 package definition using the @command{guix edit} command
2440 (@pxref{Invoking guix edit}).
2441 @xref{Packaging Guidelines}, for
2442 more information on how to test package definitions, and
2443 @ref{Invoking guix lint}, for information on how to check a definition
2444 for style conformance.
2446 Finally, updating the package definition to a new upstream version
2447 can be partly automated by the @command{guix refresh} command
2448 (@pxref{Invoking guix refresh}).
2450 Behind the scenes, a derivation corresponding to the @code{<package>}
2451 object is first computed by the @code{package-derivation} procedure.
2452 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
2453 The build actions it prescribes may then be realized by using the
2454 @code{build-derivations} procedure (@pxref{The Store}).
2456 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
2457 Return the @code{<derivation>} object of @var{package} for @var{system}
2458 (@pxref{Derivations}).
2460 @var{package} must be a valid @code{<package>} object, and @var{system}
2461 must be a string denoting the target system type---e.g.,
2462 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
2463 must be a connection to the daemon, which operates on the store
2464 (@pxref{The Store}).
2468 @cindex cross-compilation
2469 Similarly, it is possible to compute a derivation that cross-builds a
2470 package for some other system:
2472 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
2473 @var{package} @var{target} [@var{system}]
2474 Return the @code{<derivation>} object of @var{package} cross-built from
2475 @var{system} to @var{target}.
2477 @var{target} must be a valid GNU triplet denoting the target hardware
2478 and operating system, such as @code{"mips64el-linux-gnu"}
2479 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
2480 Configure and Build System}).
2484 * package Reference :: The package data type.
2485 * origin Reference:: The origin data type.
2489 @node package Reference
2490 @subsection @code{package} Reference
2492 This section summarizes all the options available in @code{package}
2493 declarations (@pxref{Defining Packages}).
2495 @deftp {Data Type} package
2496 This is the data type representing a package recipe.
2500 The name of the package, as a string.
2502 @item @code{version}
2503 The version of the package, as a string.
2506 An object telling how the source code for the package should be
2507 acquired. Most of the time, this is an @code{origin} object, which
2508 denotes a file fetched from the Internet (@pxref{origin Reference}). It
2509 can also be any other ``file-like'' object such as a @code{local-file},
2510 which denotes a file from the local file system (@pxref{G-Expressions,
2511 @code{local-file}}).
2513 @item @code{build-system}
2514 The build system that should be used to build the package (@pxref{Build
2517 @item @code{arguments} (default: @code{'()})
2518 The arguments that should be passed to the build system. This is a
2519 list, typically containing sequential keyword-value pairs.
2521 @item @code{inputs} (default: @code{'()})
2522 @itemx @code{native-inputs} (default: @code{'()})
2523 @itemx @code{propagated-inputs} (default: @code{'()})
2524 @cindex inputs, of packages
2525 These fields list dependencies of the package. Each one is a list of
2526 tuples, where each tuple has a label for the input (a string) as its
2527 first element, a package, origin, or derivation as its second element,
2528 and optionally the name of the output thereof that should be used, which
2529 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
2530 more on package outputs). For example, the list below specifies three
2534 `(("libffi" ,libffi)
2535 ("libunistring" ,libunistring)
2536 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
2539 @cindex cross compilation, package dependencies
2540 The distinction between @code{native-inputs} and @code{inputs} is
2541 necessary when considering cross-compilation. When cross-compiling,
2542 dependencies listed in @code{inputs} are built for the @emph{target}
2543 architecture; conversely, dependencies listed in @code{native-inputs}
2544 are built for the architecture of the @emph{build} machine.
2546 @code{native-inputs} is typically used to list tools needed at
2547 build time, but not at run time, such as Autoconf, Automake, pkg-config,
2548 Gettext, or Bison. @command{guix lint} can report likely mistakes in
2549 this area (@pxref{Invoking guix lint}).
2551 @anchor{package-propagated-inputs}
2552 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
2553 specified packages will be automatically installed alongside the package
2554 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
2555 package}}, for information on how @command{guix package} deals with
2558 For example this is necessary when a C/C++ library needs headers of
2559 another library to compile, or when a pkg-config file refers to another
2560 one @i{via} its @code{Requires} field.
2562 Another example where @code{propagated-inputs} is useful is for languages
2563 that lack a facility to record the run-time search path akin to the
2564 @code{RUNPATH}of ELF files; this includes Guile, Python, Perl, GHC, and
2565 more. To ensure that libraries written in those languages can find
2566 library code they depend on at run time, run-time dependencies must be
2567 listed in @code{propagated-inputs} rather than @code{inputs}.
2569 @item @code{self-native-input?} (default: @code{#f})
2570 This is a Boolean field telling whether the package should use itself as
2571 a native input when cross-compiling.
2573 @item @code{outputs} (default: @code{'("out")})
2574 The list of output names of the package. @xref{Packages with Multiple
2575 Outputs}, for typical uses of additional outputs.
2577 @item @code{native-search-paths} (default: @code{'()})
2578 @itemx @code{search-paths} (default: @code{'()})
2579 A list of @code{search-path-specification} objects describing
2580 search-path environment variables honored by the package.
2582 @item @code{replacement} (default: @code{#f})
2583 This must be either @code{#f} or a package object that will be used as a
2584 @dfn{replacement} for this package. @xref{Security Updates, grafts},
2587 @item @code{synopsis}
2588 A one-line description of the package.
2590 @item @code{description}
2591 A more elaborate description of the package.
2593 @item @code{license}
2594 The license of the package; a value from @code{(guix licenses)},
2595 or a list of such values.
2597 @item @code{home-page}
2598 The URL to the home-page of the package, as a string.
2600 @item @code{supported-systems} (default: @var{%supported-systems})
2601 The list of systems supported by the package, as strings of the form
2602 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
2604 @item @code{maintainers} (default: @code{'()})
2605 The list of maintainers of the package, as @code{maintainer} objects.
2607 @item @code{location} (default: source location of the @code{package} form)
2608 The source location of the package. It is useful to override this when
2609 inheriting from another package, in which case this field is not
2610 automatically corrected.
2615 @node origin Reference
2616 @subsection @code{origin} Reference
2618 This section summarizes all the options available in @code{origin}
2619 declarations (@pxref{Defining Packages}).
2621 @deftp {Data Type} origin
2622 This is the data type representing a source code origin.
2626 An object containing the URI of the source. The object type depends on
2627 the @code{method} (see below). For example, when using the
2628 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
2629 values are: a URL represented as a string, or a list thereof.
2632 A procedure that handles the URI.
2637 @item @var{url-fetch} from @code{(guix download)}
2638 download a file from the HTTP, HTTPS, or FTP URL specified in the
2641 @item @var{git-fetch} from @code{(guix git-download)}
2642 clone the Git version control repository, and check out the revision
2643 specified in the @code{uri} field as a @code{git-reference} object; a
2644 @code{git-reference} looks like this:
2648 (url "git://git.debian.org/git/pkg-shadow/shadow")
2649 (commit "v4.1.5.1"))
2654 A bytevector containing the SHA-256 hash of the source. Typically the
2655 @code{base32} form is used here to generate the bytevector from a
2658 @item @code{file-name} (default: @code{#f})
2659 The file name under which the source code should be saved. When this is
2660 @code{#f}, a sensible default value will be used in most cases. In case
2661 the source is fetched from a URL, the file name from the URL will be
2662 used. For version control checkouts, it is recommended to provide the
2663 file name explicitly because the default is not very descriptive.
2665 @item @code{patches} (default: @code{'()})
2666 A list of file names containing patches to be applied to the source.
2668 @item @code{snippet} (default: @code{#f})
2669 A quoted piece of code that will be run in the source directory to make
2670 any modifications, which is sometimes more convenient than a patch.
2672 @item @code{patch-flags} (default: @code{'("-p1")})
2673 A list of command-line flags that should be passed to the @code{patch}
2676 @item @code{patch-inputs} (default: @code{#f})
2677 Input packages or derivations to the patching process. When this is
2678 @code{#f}, the usual set of inputs necessary for patching are provided,
2679 such as GNU@tie{}Patch.
2681 @item @code{modules} (default: @code{'()})
2682 A list of Guile modules that should be loaded during the patching
2683 process and while running the code in the @code{snippet} field.
2685 @item @code{imported-modules} (default: @code{'()})
2686 The list of Guile modules to import in the patch derivation, for use by
2689 @item @code{patch-guile} (default: @code{#f})
2690 The Guile package that should be used in the patching process. When
2691 this is @code{#f}, a sensible default is used.
2697 @section Build Systems
2699 @cindex build system
2700 Each package definition specifies a @dfn{build system} and arguments for
2701 that build system (@pxref{Defining Packages}). This @code{build-system}
2702 field represents the build procedure of the package, as well as implicit
2703 dependencies of that build procedure.
2705 Build systems are @code{<build-system>} objects. The interface to
2706 create and manipulate them is provided by the @code{(guix build-system)}
2707 module, and actual build systems are exported by specific modules.
2709 @cindex bag (low-level package representation)
2710 Under the hood, build systems first compile package objects to
2711 @dfn{bags}. A @dfn{bag} is like a package, but with less
2712 ornamentation---in other words, a bag is a lower-level representation of
2713 a package, which includes all the inputs of that package, including some
2714 that were implicitly added by the build system. This intermediate
2715 representation is then compiled to a derivation (@pxref{Derivations}).
2717 Build systems accept an optional list of @dfn{arguments}. In package
2718 definitions, these are passed @i{via} the @code{arguments} field
2719 (@pxref{Defining Packages}). They are typically keyword arguments
2720 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
2721 Guile Reference Manual}). The value of these arguments is usually
2722 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
2723 by the daemon (@pxref{Derivations}).
2725 The main build system is @var{gnu-build-system}, which implements the
2726 standard build procedure for GNU and many other packages. It
2727 is provided by the @code{(guix build-system gnu)} module.
2729 @defvr {Scheme Variable} gnu-build-system
2730 @var{gnu-build-system} represents the GNU Build System, and variants
2731 thereof (@pxref{Configuration, configuration and makefile conventions,,
2732 standards, GNU Coding Standards}).
2734 @cindex build phases
2735 In a nutshell, packages using it are configured, built, and installed with
2736 the usual @code{./configure && make && make check && make install}
2737 command sequence. In practice, a few additional steps are often needed.
2738 All these steps are split up in separate @dfn{phases},
2739 notably@footnote{Please see the @code{(guix build gnu-build-system)}
2740 modules for more details about the build phases.}:
2744 Unpack the source tarball, and change the current directory to the
2745 extracted source tree. If the source is actually a directory, copy it
2746 to the build tree, and enter that directory.
2748 @item patch-source-shebangs
2749 Patch shebangs encountered in source files so they refer to the right
2750 store file names. For instance, this changes @code{#!/bin/sh} to
2751 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
2754 Run the @file{configure} script with a number of default options, such
2755 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
2756 by the @code{#:configure-flags} argument.
2759 Run @code{make} with the list of flags specified with
2760 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
2761 (the default), build with @code{make -j}.
2764 Run @code{make check}, or some other target specified with
2765 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
2766 @code{#:parallel-tests?} argument is true (the default), run @code{make
2770 Run @code{make install} with the flags listed in @code{#:make-flags}.
2772 @item patch-shebangs
2773 Patch shebangs on the installed executable files.
2776 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
2777 is false), copying them to the @code{debug} output when available
2778 (@pxref{Installing Debugging Files}).
2781 @vindex %standard-phases
2782 The build-side module @code{(guix build gnu-build-system)} defines
2783 @var{%standard-phases} as the default list of build phases.
2784 @var{%standard-phases} is a list of symbol/procedure pairs, where the
2785 procedure implements the actual phase.
2787 The list of phases used for a particular package can be changed with the
2788 @code{#:phases} parameter. For instance, passing:
2791 #:phases (modify-phases %standard-phases (delete 'configure))
2794 means that all the phases described above will be used, except the
2795 @code{configure} phase.
2797 In addition, this build system ensures that the ``standard'' environment
2798 for GNU packages is available. This includes tools such as GCC, libc,
2799 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
2800 build-system gnu)} module for a complete list). We call these the
2801 @dfn{implicit inputs} of a package, because package definitions do not
2802 have to mention them.
2805 Other @code{<build-system>} objects are defined to support other
2806 conventions and tools used by free software packages. They inherit most
2807 of @var{gnu-build-system}, and differ mainly in the set of inputs
2808 implicitly added to the build process, and in the list of phases
2809 executed. Some of these build systems are listed below.
2811 @defvr {Scheme Variable} ant-build-system
2812 This variable is exported by @code{(guix build-system ant)}. It
2813 implements the build procedure for Java packages that can be built with
2814 @url{http://ant.apache.org/, Ant build tool}.
2816 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
2817 provided by the @code{icedtea} package to the set of inputs. Different
2818 packages can be specified with the @code{#:ant} and @code{#:jdk}
2819 parameters, respectively.
2821 When the original package does not provide a suitable Ant build file,
2822 the parameter @code{#:jar-name} can be used to generate a minimal Ant
2823 build file @file{build.xml} with tasks to build the specified jar
2826 The parameter @code{#:build-target} can be used to specify the Ant task
2827 that should be run during the @code{build} phase. By default the
2828 ``jar'' task will be run.
2832 @defvr {Scheme Variable} cmake-build-system
2833 This variable is exported by @code{(guix build-system cmake)}. It
2834 implements the build procedure for packages using the
2835 @url{http://www.cmake.org, CMake build tool}.
2837 It automatically adds the @code{cmake} package to the set of inputs.
2838 Which package is used can be specified with the @code{#:cmake}
2841 The @code{#:configure-flags} parameter is taken as a list of flags
2842 passed to the @command{cmake} command. The @code{#:build-type}
2843 parameter specifies in abstract terms the flags passed to the compiler;
2844 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
2845 debugging information''), which roughly means that code is compiled with
2846 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
2849 @defvr {Scheme Variable} glib-or-gtk-build-system
2850 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
2851 is intended for use with packages making use of GLib or GTK+.
2853 This build system adds the following two phases to the ones defined by
2854 @var{gnu-build-system}:
2857 @item glib-or-gtk-wrap
2858 The phase @code{glib-or-gtk-wrap} ensures that programs in
2859 @file{bin/} are able to find GLib ``schemas'' and
2860 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
2861 modules}. This is achieved by wrapping the programs in launch scripts
2862 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
2863 environment variables.
2865 It is possible to exclude specific package outputs from that wrapping
2866 process by listing their names in the
2867 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
2868 when an output is known not to contain any GLib or GTK+ binaries, and
2869 where wrapping would gratuitously add a dependency of that output on
2872 @item glib-or-gtk-compile-schemas
2873 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
2874 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
2875 GSettings schemas} of GLib are compiled. Compilation is performed by the
2876 @command{glib-compile-schemas} program. It is provided by the package
2877 @code{glib:bin} which is automatically imported by the build system.
2878 The @code{glib} package providing @command{glib-compile-schemas} can be
2879 specified with the @code{#:glib} parameter.
2882 Both phases are executed after the @code{install} phase.
2885 @defvr {Scheme Variable} python-build-system
2886 This variable is exported by @code{(guix build-system python)}. It
2887 implements the more or less standard build procedure used by Python
2888 packages, which consists in running @code{python setup.py build} and
2889 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
2891 For packages that install stand-alone Python programs under @code{bin/},
2892 it takes care of wrapping these programs so that their @code{PYTHONPATH}
2893 environment variable points to all the Python libraries they depend on.
2895 Which Python package is used to perform the build can be specified with
2896 the @code{#:python} parameter. This is a useful way to force a package
2897 to be built for a specific version of the Python interpreter, which
2898 might be necessary if the package is only compatible with a single
2899 interpreter version.
2902 @defvr {Scheme Variable} perl-build-system
2903 This variable is exported by @code{(guix build-system perl)}. It
2904 implements the standard build procedure for Perl packages, which either
2905 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
2906 followed by @code{Build} and @code{Build install}; or in running
2907 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
2908 @code{make} and @code{make install}, depending on which of
2909 @code{Build.PL} or @code{Makefile.PL} is present in the package
2910 distribution. Preference is given to the former if both @code{Build.PL}
2911 and @code{Makefile.PL} exist in the package distribution. This
2912 preference can be reversed by specifying @code{#t} for the
2913 @code{#:make-maker?} parameter.
2915 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
2916 passes flags specified by the @code{#:make-maker-flags} or
2917 @code{#:module-build-flags} parameter, respectively.
2919 Which Perl package is used can be specified with @code{#:perl}.
2922 @defvr {Scheme Variable} r-build-system
2923 This variable is exported by @code{(guix build-system r)}. It
2924 implements the build procedure used by @uref{http://r-project.org, R}
2925 packages, which essentially is little more than running @code{R CMD
2926 INSTALL --library=/gnu/store/@dots{}} in an environment where
2927 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
2928 are run after installation using the R function
2929 @code{tools::testInstalledPackage}.
2932 @defvr {Scheme Variable} ruby-build-system
2933 This variable is exported by @code{(guix build-system ruby)}. It
2934 implements the RubyGems build procedure used by Ruby packages, which
2935 involves running @code{gem build} followed by @code{gem install}.
2937 The @code{source} field of a package that uses this build system
2938 typically references a gem archive, since this is the format that Ruby
2939 developers use when releasing their software. The build system unpacks
2940 the gem archive, potentially patches the source, runs the test suite,
2941 repackages the gem, and installs it. Additionally, directories and
2942 tarballs may be referenced to allow building unreleased gems from Git or
2943 a traditional source release tarball.
2945 Which Ruby package is used can be specified with the @code{#:ruby}
2946 parameter. A list of additional flags to be passed to the @command{gem}
2947 command can be specified with the @code{#:gem-flags} parameter.
2950 @defvr {Scheme Variable} waf-build-system
2951 This variable is exported by @code{(guix build-system waf)}. It
2952 implements a build procedure around the @code{waf} script. The common
2953 phases---@code{configure}, @code{build}, and @code{install}---are
2954 implemented by passing their names as arguments to the @code{waf}
2957 The @code{waf} script is executed by the Python interpreter. Which
2958 Python package is used to run the script can be specified with the
2959 @code{#:python} parameter.
2962 @defvr {Scheme Variable} haskell-build-system
2963 This variable is exported by @code{(guix build-system haskell)}. It
2964 implements the Cabal build procedure used by Haskell packages, which
2965 involves running @code{runhaskell Setup.hs configure
2966 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
2967 Instead of installing the package by running @code{runhaskell Setup.hs
2968 install}, to avoid trying to register libraries in the read-only
2969 compiler store directory, the build system uses @code{runhaskell
2970 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
2971 addition, the build system generates the package documentation by
2972 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
2973 is passed. Optional Haddock parameters can be passed with the help of
2974 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
2975 not found, the build system looks for @code{Setup.lhs} instead.
2977 Which Haskell compiler is used can be specified with the @code{#:haskell}
2978 parameter which defaults to @code{ghc}.
2981 @defvr {Scheme Variable} emacs-build-system
2982 This variable is exported by @code{(guix build-system emacs)}. It
2983 implements an installation procedure similar to the packaging system
2984 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
2986 It first creates the @code{@var{package}-autoloads.el} file, then it
2987 byte compiles all Emacs Lisp files. Differently from the Emacs
2988 packaging system, the Info documentation files are moved to the standard
2989 documentation directory and the @file{dir} file is deleted. Each
2990 package is installed in its own directory under
2991 @file{share/emacs/site-lisp/guix.d}.
2994 Lastly, for packages that do not need anything as sophisticated, a
2995 ``trivial'' build system is provided. It is trivial in the sense that
2996 it provides basically no support: it does not pull any implicit inputs,
2997 and does not have a notion of build phases.
2999 @defvr {Scheme Variable} trivial-build-system
3000 This variable is exported by @code{(guix build-system trivial)}.
3002 This build system requires a @code{#:builder} argument. This argument
3003 must be a Scheme expression that builds the package output(s)---as
3004 with @code{build-expression->derivation} (@pxref{Derivations,
3005 @code{build-expression->derivation}}).
3015 Conceptually, the @dfn{store} is the place where derivations that have
3016 been built successfully are stored---by default, @file{/gnu/store}.
3017 Sub-directories in the store are referred to as @dfn{store items} or
3018 sometimes @dfn{store paths}. The store has an associated database that
3019 contains information such as the store paths referred to by each store
3020 path, and the list of @emph{valid} store items---results of successful
3021 builds. This database resides in @file{@var{localstatedir}/guix/db},
3022 where @var{localstatedir} is the state directory specified @i{via}
3023 @option{--localstatedir} at configure time, usually @file{/var}.
3025 The store is @emph{always} accessed by the daemon on behalf of its clients
3026 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3027 connect to the daemon over a Unix-domain socket, send requests to it,
3028 and read the result---these are remote procedure calls, or RPCs.
3031 Users must @emph{never} modify files under @file{/gnu/store} directly.
3032 This would lead to inconsistencies and break the immutability
3033 assumptions of Guix's functional model (@pxref{Introduction}).
3035 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3036 how to check the integrity of the store and attempt recovery from
3037 accidental modifications.
3040 The @code{(guix store)} module provides procedures to connect to the
3041 daemon, and to perform RPCs. These are described below.
3043 @deffn {Scheme Procedure} open-connection [@var{file}] [#:reserve-space? #t]
3044 Connect to the daemon over the Unix-domain socket at @var{file}. When
3045 @var{reserve-space?} is true, instruct it to reserve a little bit of
3046 extra space on the file system so that the garbage collector can still
3047 operate should the disk become full. Return a server object.
3049 @var{file} defaults to @var{%default-socket-path}, which is the normal
3050 location given the options that were passed to @command{configure}.
3053 @deffn {Scheme Procedure} close-connection @var{server}
3054 Close the connection to @var{server}.
3057 @defvr {Scheme Variable} current-build-output-port
3058 This variable is bound to a SRFI-39 parameter, which refers to the port
3059 where build and error logs sent by the daemon should be written.
3062 Procedures that make RPCs all take a server object as their first
3065 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3066 @cindex invalid store items
3067 Return @code{#t} when @var{path} designates a valid store item and
3068 @code{#f} otherwise (an invalid item may exist on disk but still be
3069 invalid, for instance because it is the result of an aborted or failed
3072 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3073 prefixed by the store directory (@file{/gnu/store}).
3076 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3077 Add @var{text} under file @var{name} in the store, and return its store
3078 path. @var{references} is the list of store paths referred to by the
3079 resulting store path.
3082 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3083 Build @var{derivations} (a list of @code{<derivation>} objects or
3084 derivation paths), and return when the worker is done building them.
3085 Return @code{#t} on success.
3088 Note that the @code{(guix monads)} module provides a monad as well as
3089 monadic versions of the above procedures, with the goal of making it
3090 more convenient to work with code that accesses the store (@pxref{The
3094 @i{This section is currently incomplete.}
3097 @section Derivations
3100 Low-level build actions and the environment in which they are performed
3101 are represented by @dfn{derivations}. A derivation contains the
3102 following pieces of information:
3106 The outputs of the derivation---derivations produce at least one file or
3107 directory in the store, but may produce more.
3110 The inputs of the derivations, which may be other derivations or plain
3111 files in the store (patches, build scripts, etc.)
3114 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3117 The file name of a build script in the store, along with the arguments
3121 A list of environment variables to be defined.
3125 @cindex derivation path
3126 Derivations allow clients of the daemon to communicate build actions to
3127 the store. They exist in two forms: as an in-memory representation,
3128 both on the client- and daemon-side, and as files in the store whose
3129 name end in @code{.drv}---these files are referred to as @dfn{derivation
3130 paths}. Derivations paths can be passed to the @code{build-derivations}
3131 procedure to perform the build actions they prescribe (@pxref{The
3134 The @code{(guix derivations)} module provides a representation of
3135 derivations as Scheme objects, along with procedures to create and
3136 otherwise manipulate derivations. The lowest-level primitive to create
3137 a derivation is the @code{derivation} procedure:
3139 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3140 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3141 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3142 [#:system (%current-system)] [#:references-graphs #f] @
3143 [#:allowed-references #f] [#:disallowed-references #f] @
3144 [#:leaked-env-vars #f] [#:local-build? #f] @
3145 [#:substitutable? #t]
3146 Build a derivation with the given arguments, and return the resulting
3147 @code{<derivation>} object.
3149 When @var{hash} and @var{hash-algo} are given, a
3150 @dfn{fixed-output derivation} is created---i.e., one whose result is
3151 known in advance, such as a file download. If, in addition,
3152 @var{recursive?} is true, then that fixed output may be an executable
3153 file or a directory and @var{hash} must be the hash of an archive
3154 containing this output.
3156 When @var{references-graphs} is true, it must be a list of file
3157 name/store path pairs. In that case, the reference graph of each store
3158 path is exported in the build environment in the corresponding file, in
3159 a simple text format.
3161 When @var{allowed-references} is true, it must be a list of store items
3162 or outputs that the derivation's output may refer to. Likewise,
3163 @var{disallowed-references}, if true, must be a list of things the
3164 outputs may @emph{not} refer to.
3166 When @var{leaked-env-vars} is true, it must be a list of strings
3167 denoting environment variables that are allowed to ``leak'' from the
3168 daemon's environment to the build environment. This is only applicable
3169 to fixed-output derivations---i.e., when @var{hash} is true. The main
3170 use is to allow variables such as @code{http_proxy} to be passed to
3171 derivations that download files.
3173 When @var{local-build?} is true, declare that the derivation is not a
3174 good candidate for offloading and should rather be built locally
3175 (@pxref{Daemon Offload Setup}). This is the case for small derivations
3176 where the costs of data transfers would outweigh the benefits.
3178 When @var{substitutable?} is false, declare that substitutes of the
3179 derivation's output should not be used (@pxref{Substitutes}). This is
3180 useful, for instance, when building packages that capture details of the
3181 host CPU instruction set.
3185 Here's an example with a shell script as its builder, assuming
3186 @var{store} is an open connection to the daemon, and @var{bash} points
3187 to a Bash executable in the store:
3190 (use-modules (guix utils)
3194 (let ((builder ; add the Bash script to the store
3195 (add-text-to-store store "my-builder.sh"
3196 "echo hello world > $out\n" '())))
3197 (derivation store "foo"
3198 bash `("-e" ,builder)
3199 #:inputs `((,bash) (,builder))
3200 #:env-vars '(("HOME" . "/homeless"))))
3201 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
3204 As can be guessed, this primitive is cumbersome to use directly. A
3205 better approach is to write build scripts in Scheme, of course! The
3206 best course of action for that is to write the build code as a
3207 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
3208 information, @pxref{G-Expressions}.
3210 Once upon a time, @code{gexp->derivation} did not exist and constructing
3211 derivations with build code written in Scheme was achieved with
3212 @code{build-expression->derivation}, documented below. This procedure
3213 is now deprecated in favor of the much nicer @code{gexp->derivation}.
3215 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
3216 @var{name} @var{exp} @
3217 [#:system (%current-system)] [#:inputs '()] @
3218 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3219 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3220 [#:references-graphs #f] [#:allowed-references #f] @
3221 [#:disallowed-references #f] @
3222 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3223 Return a derivation that executes Scheme expression @var{exp} as a
3224 builder for derivation @var{name}. @var{inputs} must be a list of
3225 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
3226 @code{"out"} is assumed. @var{modules} is a list of names of Guile
3227 modules from the current search path to be copied in the store,
3228 compiled, and made available in the load path during the execution of
3229 @var{exp}---e.g., @code{((guix build utils) (guix build
3230 gnu-build-system))}.
3232 @var{exp} is evaluated in an environment where @code{%outputs} is bound
3233 to a list of output/path pairs, and where @code{%build-inputs} is bound
3234 to a list of string/output-path pairs made from @var{inputs}.
3235 Optionally, @var{env-vars} is a list of string pairs specifying the name
3236 and value of environment variables visible to the builder. The builder
3237 terminates by passing the result of @var{exp} to @code{exit}; thus, when
3238 @var{exp} returns @code{#f}, the build is considered to have failed.
3240 @var{exp} is built using @var{guile-for-build} (a derivation). When
3241 @var{guile-for-build} is omitted or is @code{#f}, the value of the
3242 @code{%guile-for-build} fluid is used instead.
3244 See the @code{derivation} procedure for the meaning of
3245 @var{references-graphs}, @var{allowed-references},
3246 @var{disallowed-references}, @var{local-build?}, and
3247 @var{substitutable?}.
3251 Here's an example of a single-output derivation that creates a directory
3252 containing one file:
3255 (let ((builder '(let ((out (assoc-ref %outputs "out")))
3256 (mkdir out) ; create /gnu/store/@dots{}-goo
3257 (call-with-output-file (string-append out "/test")
3259 (display '(hello guix) p))))))
3260 (build-expression->derivation store "goo" builder))
3262 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
3266 @node The Store Monad
3267 @section The Store Monad
3271 The procedures that operate on the store described in the previous
3272 sections all take an open connection to the build daemon as their first
3273 argument. Although the underlying model is functional, they either have
3274 side effects or depend on the current state of the store.
3276 The former is inconvenient: the connection to the build daemon has to be
3277 carried around in all those functions, making it impossible to compose
3278 functions that do not take that parameter with functions that do. The
3279 latter can be problematic: since store operations have side effects
3280 and/or depend on external state, they have to be properly sequenced.
3282 @cindex monadic values
3283 @cindex monadic functions
3284 This is where the @code{(guix monads)} module comes in. This module
3285 provides a framework for working with @dfn{monads}, and a particularly
3286 useful monad for our uses, the @dfn{store monad}. Monads are a
3287 construct that allows two things: associating ``context'' with values
3288 (in our case, the context is the store), and building sequences of
3289 computations (here computations include accesses to the store). Values
3290 in a monad---values that carry this additional context---are called
3291 @dfn{monadic values}; procedures that return such values are called
3292 @dfn{monadic procedures}.
3294 Consider this ``normal'' procedure:
3297 (define (sh-symlink store)
3298 ;; Return a derivation that symlinks the 'bash' executable.
3299 (let* ((drv (package-derivation store bash))
3300 (out (derivation->output-path drv))
3301 (sh (string-append out "/bin/bash")))
3302 (build-expression->derivation store "sh"
3303 `(symlink ,sh %output))))
3306 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
3307 as a monadic function:
3310 (define (sh-symlink)
3311 ;; Same, but return a monadic value.
3312 (mlet %store-monad ((drv (package->derivation bash)))
3313 (gexp->derivation "sh"
3314 #~(symlink (string-append #$drv "/bin/bash")
3318 There are several things to note in the second version: the @code{store}
3319 parameter is now implicit and is ``threaded'' in the calls to the
3320 @code{package->derivation} and @code{gexp->derivation} monadic
3321 procedures, and the monadic value returned by @code{package->derivation}
3322 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
3324 As it turns out, the call to @code{package->derivation} can even be
3325 omitted since it will take place implicitly, as we will see later
3326 (@pxref{G-Expressions}):
3329 (define (sh-symlink)
3330 (gexp->derivation "sh"
3331 #~(symlink (string-append #$bash "/bin/bash")
3336 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
3337 @c for the funny quote.
3338 Calling the monadic @code{sh-symlink} has no effect. As someone once
3339 said, ``you exit a monad like you exit a building on fire: by running''.
3340 So, to exit the monad and get the desired effect, one must use
3341 @code{run-with-store}:
3344 (run-with-store (open-connection) (sh-symlink))
3345 @result{} /gnu/store/...-sh-symlink
3348 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
3349 new ``meta-commands'' to make it easier to deal with monadic procedures:
3350 @code{run-in-store}, and @code{enter-store-monad}. The former is used
3351 to ``run'' a single monadic value through the store:
3354 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
3355 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
3358 The latter enters a recursive REPL, where all the return values are
3359 automatically run through the store:
3362 scheme@@(guile-user)> ,enter-store-monad
3363 store-monad@@(guile-user) [1]> (package->derivation hello)
3364 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
3365 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
3366 $3 = "/gnu/store/@dots{}-foo"
3367 store-monad@@(guile-user) [1]> ,q
3368 scheme@@(guile-user)>
3372 Note that non-monadic values cannot be returned in the
3373 @code{store-monad} REPL.
3375 The main syntactic forms to deal with monads in general are provided by
3376 the @code{(guix monads)} module and are described below.
3378 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
3379 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
3383 @deffn {Scheme Syntax} return @var{val}
3384 Return a monadic value that encapsulates @var{val}.
3387 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
3388 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
3389 procedures @var{mproc}@dots{}@footnote{This operation is commonly
3390 referred to as ``bind'', but that name denotes an unrelated procedure in
3391 Guile. Thus we use this somewhat cryptic symbol inherited from the
3392 Haskell language.}. There can be one @var{mproc} or several of them, as
3397 (with-monad %state-monad
3399 (lambda (x) (return (+ 1 x)))
3400 (lambda (x) (return (* 2 x)))))
3404 @result{} some-state
3408 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
3410 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
3412 Bind the variables @var{var} to the monadic values @var{mval} in
3413 @var{body}. The form (@var{var} -> @var{val}) binds @var{var} to the
3414 ``normal'' value @var{val}, as per @code{let}.
3416 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
3417 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
3420 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
3421 Bind @var{mexp} and the following monadic expressions in sequence,
3422 returning the result of the last expression.
3424 This is akin to @code{mlet}, except that the return values of the
3425 monadic expressions are ignored. In that sense, it is analogous to
3426 @code{begin}, but applied to monadic expressions.
3430 The @code{(guix monads)} module provides the @dfn{state monad}, which
3431 allows an additional value---the state---to be @emph{threaded} through
3432 monadic procedure calls.
3434 @defvr {Scheme Variable} %state-monad
3435 The state monad. Procedures in the state monad can access and change
3436 the state that is threaded.
3438 Consider the example below. The @code{square} procedure returns a value
3439 in the state monad. It returns the square of its argument, but also
3440 increments the current state value:
3444 (mlet %state-monad ((count (current-state)))
3445 (mbegin %state-monad
3446 (set-current-state (+ 1 count))
3449 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
3454 When ``run'' through @var{%state-monad}, we obtain that additional state
3455 value, which is the number of @code{square} calls.
3458 @deffn {Monadic Procedure} current-state
3459 Return the current state as a monadic value.
3462 @deffn {Monadic Procedure} set-current-state @var{value}
3463 Set the current state to @var{value} and return the previous state as a
3467 @deffn {Monadic Procedure} state-push @var{value}
3468 Push @var{value} to the current state, which is assumed to be a list,
3469 and return the previous state as a monadic value.
3472 @deffn {Monadic Procedure} state-pop
3473 Pop a value from the current state and return it as a monadic value.
3474 The state is assumed to be a list.
3477 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
3478 Run monadic value @var{mval} starting with @var{state} as the initial
3479 state. Return two values: the resulting value, and the resulting state.
3482 The main interface to the store monad, provided by the @code{(guix
3483 store)} module, is as follows.
3485 @defvr {Scheme Variable} %store-monad
3486 The store monad---an alias for @var{%state-monad}.
3488 Values in the store monad encapsulate accesses to the store. When its
3489 effect is needed, a value of the store monad must be ``evaluated'' by
3490 passing it to the @code{run-with-store} procedure (see below.)
3493 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
3494 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
3495 open store connection.
3498 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
3499 Return as a monadic value the absolute file name in the store of the file
3500 containing @var{text}, a string. @var{references} is a list of store items that the
3501 resulting text file refers to; it defaults to the empty list.
3504 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
3505 [#:recursive? #t] [#:select? (const #t)]
3506 Return the name of @var{file} once interned in the store. Use
3507 @var{name} as its store name, or the basename of @var{file} if
3508 @var{name} is omitted.
3510 When @var{recursive?} is true, the contents of @var{file} are added
3511 recursively; if @var{file} designates a flat file and @var{recursive?}
3512 is true, its contents are added, and its permission bits are kept.
3514 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
3515 @var{stat})} for each directory entry, where @var{file} is the entry's
3516 absolute file name and @var{stat} is the result of @code{lstat}; exclude
3517 entries for which @var{select?} does not return true.
3519 The example below adds a file to the store, under two different names:
3522 (run-with-store (open-connection)
3523 (mlet %store-monad ((a (interned-file "README"))
3524 (b (interned-file "README" "LEGU-MIN")))
3525 (return (list a b))))
3527 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
3532 The @code{(guix packages)} module exports the following package-related
3535 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
3536 [#:system (%current-system)] [#:target #f] @
3539 value in the absolute file name of @var{file} within the @var{output}
3540 directory of @var{package}. When @var{file} is omitted, return the name
3541 of the @var{output} directory of @var{package}. When @var{target} is
3542 true, use it as a cross-compilation target triplet.
3545 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
3546 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
3547 @var{target} [@var{system}]
3548 Monadic version of @code{package-derivation} and
3549 @code{package-cross-derivation} (@pxref{Defining Packages}).
3554 @section G-Expressions
3556 @cindex G-expression
3557 @cindex build code quoting
3558 So we have ``derivations'', which represent a sequence of build actions
3559 to be performed to produce an item in the store (@pxref{Derivations}).
3560 These build actions are performed when asking the daemon to actually
3561 build the derivations; they are run by the daemon in a container
3562 (@pxref{Invoking guix-daemon}).
3564 @cindex strata of code
3565 It should come as no surprise that we like to write these build actions
3566 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
3567 code@footnote{The term @dfn{stratum} in this context was coined by
3568 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
3569 Kiselyov, who has written insightful
3570 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
3571 on this topic}, refers to this kind of code generation as
3572 @dfn{staging}.}: the ``host code''---code that defines packages, talks
3573 to the daemon, etc.---and the ``build code''---code that actually
3574 performs build actions, such as making directories, invoking
3575 @command{make}, etc.
3577 To describe a derivation and its build actions, one typically needs to
3578 embed build code inside host code. It boils down to manipulating build
3579 code as data, and the homoiconicity of Scheme---code has a direct
3580 representation as data---comes in handy for that. But we need more than
3581 the normal @code{quasiquote} mechanism in Scheme to construct build
3584 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
3585 S-expressions adapted to build expressions. G-expressions, or
3586 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
3587 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
3588 @code{#$}, and @code{#$@@}), which are comparable to
3589 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
3590 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
3591 GNU Guile Reference Manual}). However, there are major differences:
3595 Gexps are meant to be written to a file and run or manipulated by other
3599 When a high-level object such as a package or derivation is unquoted
3600 inside a gexp, the result is as if its output file name had been
3604 Gexps carry information about the packages or derivations they refer to,
3605 and these dependencies are automatically added as inputs to the build
3606 processes that use them.
3609 @cindex lowering, of high-level objects in gexps
3610 This mechanism is not limited to package and derivation
3611 objects: @dfn{compilers} able to ``lower'' other high-level objects to
3612 derivations or files in the store can be defined,
3613 such that these objects can also be inserted
3614 into gexps. For example, a useful type of high-level objects that can be
3615 inserted in a gexp is ``file-like objects'', which make it easy to
3616 add files to the store and to refer to them in
3617 derivations and such (see @code{local-file} and @code{plain-file}
3620 To illustrate the idea, here is an example of a gexp:
3627 (symlink (string-append #$coreutils "/bin/ls")
3631 This gexp can be passed to @code{gexp->derivation}; we obtain a
3632 derivation that builds a directory containing exactly one symlink to
3633 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
3636 (gexp->derivation "the-thing" build-exp)
3639 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
3640 substituted to the reference to the @var{coreutils} package in the
3641 actual build code, and @var{coreutils} is automatically made an input to
3642 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
3643 output)}) is replaced by a string containing the directory name of the
3644 output of the derivation.
3646 @cindex cross compilation
3647 In a cross-compilation context, it is useful to distinguish between
3648 references to the @emph{native} build of a package---that can run on the
3649 host---versus references to cross builds of a package. To that end, the
3650 @code{#+} plays the same role as @code{#$}, but is a reference to a
3651 native package build:
3654 (gexp->derivation "vi"
3657 (system* (string-append #+coreutils "/bin/ln")
3659 (string-append #$emacs "/bin/emacs")
3660 (string-append #$output "/bin/vi")))
3661 #:target "mips64el-linux")
3665 In the example above, the native build of @var{coreutils} is used, so
3666 that @command{ln} can actually run on the host; but then the
3667 cross-compiled build of @var{emacs} is referenced.
3669 The syntactic form to construct gexps is summarized below.
3671 @deffn {Scheme Syntax} #~@var{exp}
3672 @deffnx {Scheme Syntax} (gexp @var{exp})
3673 Return a G-expression containing @var{exp}. @var{exp} may contain one
3674 or more of the following forms:
3678 @itemx (ungexp @var{obj})
3679 Introduce a reference to @var{obj}. @var{obj} may have one of the
3680 supported types, for example a package or a
3681 derivation, in which case the @code{ungexp} form is replaced by its
3682 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
3684 If @var{obj} is a list, it is traversed and references to supported
3685 objects are substituted similarly.
3687 If @var{obj} is another gexp, its contents are inserted and its
3688 dependencies are added to those of the containing gexp.
3690 If @var{obj} is another kind of object, it is inserted as is.
3692 @item #$@var{obj}:@var{output}
3693 @itemx (ungexp @var{obj} @var{output})
3694 This is like the form above, but referring explicitly to the
3695 @var{output} of @var{obj}---this is useful when @var{obj} produces
3696 multiple outputs (@pxref{Packages with Multiple Outputs}).
3699 @itemx #+@var{obj}:output
3700 @itemx (ungexp-native @var{obj})
3701 @itemx (ungexp-native @var{obj} @var{output})
3702 Same as @code{ungexp}, but produces a reference to the @emph{native}
3703 build of @var{obj} when used in a cross compilation context.
3705 @item #$output[:@var{output}]
3706 @itemx (ungexp output [@var{output}])
3707 Insert a reference to derivation output @var{output}, or to the main
3708 output when @var{output} is omitted.
3710 This only makes sense for gexps passed to @code{gexp->derivation}.
3713 @itemx (ungexp-splicing @var{lst})
3714 Like the above, but splices the contents of @var{lst} inside the
3718 @itemx (ungexp-native-splicing @var{lst})
3719 Like the above, but refers to native builds of the objects listed in
3724 G-expressions created by @code{gexp} or @code{#~} are run-time objects
3725 of the @code{gexp?} type (see below.)
3728 @deffn {Scheme Procedure} gexp? @var{obj}
3729 Return @code{#t} if @var{obj} is a G-expression.
3732 G-expressions are meant to be written to disk, either as code building
3733 some derivation, or as plain files in the store. The monadic procedures
3734 below allow you to do that (@pxref{The Store Monad}, for more
3735 information about monads.)
3737 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
3738 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
3739 [#:hash #f] [#:hash-algo #f] @
3740 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3741 [#:module-path @var{%load-path}] @
3742 [#:references-graphs #f] [#:allowed-references #f] @
3743 [#:disallowed-references #f] @
3744 [#:leaked-env-vars #f] @
3745 [#:script-name (string-append @var{name} "-builder")] @
3746 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3747 Return a derivation @var{name} that runs @var{exp} (a gexp) with
3748 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
3749 stored in a file called @var{script-name}. When @var{target} is true,
3750 it is used as the cross-compilation target triplet for packages referred
3753 Make @var{modules} available in the evaluation context of @var{exp};
3754 @var{modules} is a list of names of Guile modules searched in
3755 @var{module-path} to be copied in the store, compiled, and made available in
3756 the load path during the execution of @var{exp}---e.g., @code{((guix
3757 build utils) (guix build gnu-build-system))}.
3759 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
3762 When @var{references-graphs} is true, it must be a list of tuples of one of the
3766 (@var{file-name} @var{package})
3767 (@var{file-name} @var{package} @var{output})
3768 (@var{file-name} @var{derivation})
3769 (@var{file-name} @var{derivation} @var{output})
3770 (@var{file-name} @var{store-item})
3773 The right-hand-side of each element of @var{references-graphs} is automatically made
3774 an input of the build process of @var{exp}. In the build environment, each
3775 @var{file-name} contains the reference graph of the corresponding item, in a simple
3778 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
3779 In the latter case, the list denotes store items that the result is allowed to
3780 refer to. Any reference to another store item will lead to a build error.
3781 Similarly for @var{disallowed-references}, which can list items that must not be
3782 referenced by the outputs.
3784 The other arguments are as for @code{derivation} (@pxref{Derivations}).
3787 @cindex file-like objects
3788 The @code{local-file}, @code{plain-file}, @code{computed-file},
3789 @code{program-file}, and @code{scheme-file} procedures below return
3790 @dfn{file-like objects}. That is, when unquoted in a G-expression,
3791 these objects lead to a file in the store. Consider this G-expression:
3794 #~(system* (string-append #$glibc "/sbin/nscd") "-f"
3795 #$(local-file "/tmp/my-nscd.conf"))
3798 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
3799 to the store. Once expanded, for instance @i{via}
3800 @code{gexp->derivation}, the G-expression refers to that copy under
3801 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
3802 does not have any effect on what the G-expression does.
3803 @code{plain-file} can be used similarly; it differs in that the file
3804 content is directly passed as a string.
3806 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
3808 Return an object representing local file @var{file} to add to the store; this
3809 object can be used in a gexp. If @var{file} is a relative file name, it is looked
3810 up relative to the source file where this form appears. @var{file} will be added to
3811 the store under @var{name}--by default the base name of @var{file}.
3813 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
3814 designates a flat file and @var{recursive?} is true, its contents are added, and its
3815 permission bits are kept.
3817 This is the declarative counterpart of the @code{interned-file} monadic
3818 procedure (@pxref{The Store Monad, @code{interned-file}}).
3821 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
3822 Return an object representing a text file called @var{name} with the given
3823 @var{content} (a string) to be added to the store.
3825 This is the declarative counterpart of @code{text-file}.
3828 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
3829 [#:modules '()] [#:options '(#:local-build? #t)]
3830 Return an object representing the store item @var{name}, a file or
3831 directory computed by @var{gexp}. @var{modules} specifies the set of
3832 modules visible in the execution context of @var{gexp}. @var{options}
3833 is a list of additional arguments to pass to @code{gexp->derivation}.
3835 This is the declarative counterpart of @code{gexp->derivation}.
3838 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
3839 Return an executable script @var{name} that runs @var{exp} using
3840 @var{guile} with @var{modules} in its search path.
3842 The example below builds a script that simply invokes the @command{ls}
3846 (use-modules (guix gexp) (gnu packages base))
3848 (gexp->script "list-files"
3849 #~(execl (string-append #$coreutils "/bin/ls")
3853 When ``running'' it through the store (@pxref{The Store Monad,
3854 @code{run-with-store}}), we obtain a derivation that produces an
3855 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
3858 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
3860 (execl (string-append "/gnu/store/@dots{}-coreutils-8.22"/bin/ls")
3865 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
3866 [#:modules '()] [#:guile #f]
3867 Return an object representing the executable store item @var{name} that
3868 runs @var{gexp}. @var{guile} is the Guile package used to execute that
3869 script, and @var{modules} is the list of modules visible to that script.
3871 This is the declarative counterpart of @code{gexp->script}.
3874 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp}
3875 Return a derivation that builds a file @var{name} containing @var{exp}.
3877 The resulting file holds references to all the dependencies of @var{exp}
3878 or a subset thereof.
3881 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
3882 Return an object representing the Scheme file @var{name} that contains
3885 This is the declarative counterpart of @code{gexp->file}.
3888 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
3889 Return as a monadic value a derivation that builds a text file
3890 containing all of @var{text}. @var{text} may list, in addition to
3891 strings, objects of any type that can be used in a gexp: packages,
3892 derivations, local file objects, etc. The resulting store file holds
3893 references to all these.
3895 This variant should be preferred over @code{text-file} anytime the file
3896 to create will reference items from the store. This is typically the
3897 case when building a configuration file that embeds store file names,
3901 (define (profile.sh)
3902 ;; Return the name of a shell script in the store that
3903 ;; initializes the 'PATH' environment variable.
3904 (text-file* "profile.sh"
3905 "export PATH=" coreutils "/bin:"
3906 grep "/bin:" sed "/bin\n"))
3909 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
3910 will references @var{coreutils}, @var{grep}, and @var{sed}, thereby
3911 preventing them from being garbage-collected during its lifetime.
3914 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
3915 Return an object representing store file @var{name} containing
3916 @var{text}. @var{text} is a sequence of strings and file-like objects,
3920 (mixed-text-file "profile"
3921 "export PATH=" coreutils "/bin:" grep "/bin")
3924 This is the declarative counterpart of @code{text-file*}.
3927 Of course, in addition to gexps embedded in ``host'' code, there are
3928 also modules containing build tools. To make it clear that they are
3929 meant to be used in the build stratum, these modules are kept in the
3930 @code{(guix build @dots{})} name space.
3932 @cindex lowering, of high-level objects in gexps
3933 Internally, high-level objects are @dfn{lowered}, using their compiler,
3934 to either derivations or store items. For instance, lowering a package
3935 yields a derivation, and lowering a @code{plain-file} yields a store
3936 item. This is achieved using the @code{lower-object} monadic procedure.
3938 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
3940 Return as a value in @var{%store-monad} the derivation or store item
3941 corresponding to @var{obj} for @var{system}, cross-compiling for
3942 @var{target} if @var{target} is true. @var{obj} must be an object that
3943 has an associated gexp compiler, such as a @code{<package>}.
3947 @c *********************************************************************
3951 This section describes Guix command-line utilities. Some of them are
3952 primarily targeted at developers and users who write new package
3953 definitions, while others are more generally useful. They complement
3954 the Scheme programming interface of Guix in a convenient way.
3957 * Invoking guix build:: Building packages from the command line.
3958 * Invoking guix edit:: Editing package definitions.
3959 * Invoking guix download:: Downloading a file and printing its hash.
3960 * Invoking guix hash:: Computing the cryptographic hash of a file.
3961 * Invoking guix import:: Importing package definitions.
3962 * Invoking guix refresh:: Updating package definitions.
3963 * Invoking guix lint:: Finding errors in package definitions.
3964 * Invoking guix size:: Profiling disk usage.
3965 * Invoking guix graph:: Visualizing the graph of packages.
3966 * Invoking guix environment:: Setting up development environments.
3967 * Invoking guix publish:: Sharing substitutes.
3968 * Invoking guix challenge:: Challenging substitute servers.
3969 * Invoking guix container:: Process isolation.
3972 @node Invoking guix build
3973 @section Invoking @command{guix build}
3975 The @command{guix build} command builds packages or derivations and
3976 their dependencies, and prints the resulting store paths. Note that it
3977 does not modify the user's profile---this is the job of the
3978 @command{guix package} command (@pxref{Invoking guix package}). Thus,
3979 it is mainly useful for distribution developers.
3981 The general syntax is:
3984 guix build @var{options} @var{package-or-derivation}@dots{}
3987 As an example, the following command builds the latest versions of Emacs
3988 and of Guile, displays their build logs, and finally displays the
3989 resulting directories:
3992 guix build emacs guile
3995 Similarly, the following command builds all the available packages:
3998 guix build --quiet --keep-going \
3999 `guix package -A | cut -f1,2 --output-delimiter=@@`
4002 @var{package-or-derivation} may be either the name of a package found in
4003 the software distribution such as @code{coreutils} or
4004 @code{coreutils-8.20}, or a derivation such as
4005 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4006 package with the corresponding name (and optionally version) is searched
4007 for among the GNU distribution modules (@pxref{Package Modules}).
4009 Alternatively, the @code{--expression} option may be used to specify a
4010 Scheme expression that evaluates to a package; this is useful when
4011 disambiguation among several same-named packages or package variants is
4014 There may be zero or more @var{options}. The available options are
4015 described in the subsections below.
4018 * Common Build Options:: Build options for most commands.
4019 * Package Transformation Options:: Creating variants of packages.
4020 * Additional Build Options:: Options specific to 'guix build'.
4023 @node Common Build Options
4024 @subsection Common Build Options
4026 A number of options that control the build process are common to
4027 @command{guix build} and other commands that can spawn builds, such as
4028 @command{guix package} or @command{guix archive}. These are the
4033 @item --load-path=@var{directory}
4034 @itemx -L @var{directory}
4035 Add @var{directory} to the front of the package module search path
4036 (@pxref{Package Modules}).
4038 This allows users to define their own packages and make them visible to
4039 the command-line tools.
4043 Keep the build tree of failed builds. Thus, if a build fail, its build
4044 tree is kept under @file{/tmp}, in a directory whose name is shown at
4045 the end of the build log. This is useful when debugging build issues.
4049 Keep going when some of the derivations fail to build; return only once
4050 all the builds have either completed or failed.
4052 The default behavior is to stop as soon as one of the specified
4053 derivations has failed.
4057 Do not build the derivations.
4060 When substituting a pre-built binary fails, fall back to building
4063 @item --substitute-urls=@var{urls}
4064 @anchor{client-substitute-urls}
4065 Consider @var{urls} the whitespace-separated list of substitute source
4066 URLs, overriding the default list of URLs of @command{guix-daemon}
4067 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
4069 This means that substitutes may be downloaded from @var{urls}, provided
4070 they are signed by a key authorized by the system administrator
4071 (@pxref{Substitutes}).
4073 When @var{urls} is the empty string, substitutes are effectively
4076 @item --no-substitutes
4077 Do not use substitutes for build products. That is, always build things
4078 locally instead of allowing downloads of pre-built binaries
4079 (@pxref{Substitutes}).
4082 Do not ``graft'' packages. In practice, this means that package updates
4083 available as grafts are not applied. @xref{Security Updates}, for more
4084 information on grafts.
4086 @item --rounds=@var{n}
4087 Build each derivation @var{n} times in a row, and raise an error if
4088 consecutive build results are not bit-for-bit identical.
4090 This is a useful way to detect non-deterministic builds processes.
4091 Non-deterministic build processes are a problem because they make it
4092 practically impossible for users to @emph{verify} whether third-party
4093 binaries are genuine. @xref{Invoking guix challenge}, for more.
4095 Note that, currently, the differing build results are not kept around,
4096 so you will have to manually investigate in case of an error---e.g., by
4097 stashing one of the build results with @code{guix archive --export}
4098 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
4101 @item --no-build-hook
4102 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
4103 (@pxref{Daemon Offload Setup}). That is, always build things locally
4104 instead of offloading builds to remote machines.
4106 @item --max-silent-time=@var{seconds}
4107 When the build or substitution process remains silent for more than
4108 @var{seconds}, terminate it and report a build failure.
4110 @item --timeout=@var{seconds}
4111 Likewise, when the build or substitution process lasts for more than
4112 @var{seconds}, terminate it and report a build failure.
4114 By default there is no timeout. This behavior can be restored with
4117 @item --verbosity=@var{level}
4118 Use the given verbosity level. @var{level} must be an integer between 0
4119 and 5; higher means more verbose output. Setting a level of 4 or more
4120 may be helpful when debugging setup issues with the build daemon.
4122 @item --cores=@var{n}
4124 Allow the use of up to @var{n} CPU cores for the build. The special
4125 value @code{0} means to use as many CPU cores as available.
4127 @item --max-jobs=@var{n}
4129 Allow at most @var{n} build jobs in parallel. @xref{Invoking
4130 guix-daemon, @code{--max-jobs}}, for details about this option and the
4131 equivalent @command{guix-daemon} option.
4135 Behind the scenes, @command{guix build} is essentially an interface to
4136 the @code{package-derivation} procedure of the @code{(guix packages)}
4137 module, and to the @code{build-derivations} procedure of the @code{(guix
4138 derivations)} module.
4140 In addition to options explicitly passed on the command line,
4141 @command{guix build} and other @command{guix} commands that support
4142 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
4144 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
4145 Users can define this variable to a list of command line options that
4146 will automatically be used by @command{guix build} and other
4147 @command{guix} commands that can perform builds, as in the example
4151 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
4154 These options are parsed independently, and the result is appended to
4155 the parsed command-line options.
4159 @node Package Transformation Options
4160 @subsection Package Transformation Options
4162 @cindex package variants
4163 Another set of command-line options supported by @command{guix build}
4164 and also @command{guix package} are @dfn{package transformation
4165 options}. These are options that make it possible to define @dfn{package
4166 variants}---for instance, packages built from different source code.
4167 This is a convenient way to create customized packages on the fly
4168 without having to type in the definitions of package variants
4169 (@pxref{Defining Packages}).
4173 @item --with-source=@var{source}
4174 Use @var{source} as the source of the corresponding package.
4175 @var{source} must be a file name or a URL, as for @command{guix
4176 download} (@pxref{Invoking guix download}).
4178 The ``corresponding package'' is taken to be the one specified on the
4179 command line the name of which matches the base of @var{source}---e.g.,
4180 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
4181 package is @code{guile}. Likewise, the version string is inferred from
4182 @var{source}; in the previous example, it is @code{2.0.10}.
4184 This option allows users to try out versions of packages other than the
4185 one provided by the distribution. The example below downloads
4186 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
4187 the @code{ed} package:
4190 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
4193 As a developer, @code{--with-source} makes it easy to test release
4197 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
4200 @dots{} or to build from a checkout in a pristine environment:
4203 $ git clone git://git.sv.gnu.org/guix.git
4204 $ guix build guix --with-source=./guix
4207 @item --with-input=@var{package}=@var{replacement}
4208 Replace dependency on @var{package} by a dependency on
4209 @var{replacement}. @var{package} must be a package name, and
4210 @var{replacement} must be a package specification such as @code{guile}
4211 or @code{guile@@1.8}.
4213 For instance, the following command builds Guix, but replaces its
4214 dependency on the current stable version of Guile with a dependency on
4215 the development version of Guile, @code{guile-next}:
4218 guix build --with-input=guile=guile-next guix
4221 This is a recursive, deep replacement. So in this example, both
4222 @code{guix} and its dependency @code{guile-json} (which also depends on
4223 @code{guile}) get rebuilt against @code{guile-next}.
4225 However, implicit inputs are left unchanged.
4228 @node Additional Build Options
4229 @subsection Additional Build Options
4231 The command-line options presented below are specific to @command{guix
4238 Build quietly, without displaying the build log. Upon completion, the
4239 build log is kept in @file{/var} (or similar) and can always be
4240 retrieved using the @option{--log-file} option.
4242 @item --file=@var{file}
4243 @itemx -f @var{file}
4245 Build the package or derivation that the code within @var{file}
4248 As an example, @var{file} might contain a package definition like this
4249 (@pxref{Defining Packages}):
4252 @verbatiminclude package-hello.scm
4255 @item --expression=@var{expr}
4256 @itemx -e @var{expr}
4257 Build the package or derivation @var{expr} evaluates to.
4259 For example, @var{expr} may be @code{(@@ (gnu packages guile)
4260 guile-1.8)}, which unambiguously designates this specific variant of
4261 version 1.8 of Guile.
4263 Alternatively, @var{expr} may be a G-expression, in which case it is used
4264 as a build program passed to @code{gexp->derivation}
4265 (@pxref{G-Expressions}).
4267 Lastly, @var{expr} may refer to a zero-argument monadic procedure
4268 (@pxref{The Store Monad}). The procedure must return a derivation as a
4269 monadic value, which is then passed through @code{run-with-store}.
4273 Build the source derivations of the packages, rather than the packages
4276 For instance, @code{guix build -S gcc} returns something like
4277 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
4280 The returned source tarball is the result of applying any patches and
4281 code snippets specified in the package @code{origin} (@pxref{Defining
4285 Fetch and return the source of @var{package-or-derivation} and all their
4286 dependencies, recursively. This is a handy way to obtain a local copy
4287 of all the source code needed to build @var{packages}, allowing you to
4288 eventually build them even without network access. It is an extension
4289 of the @code{--source} option and can accept one of the following
4290 optional argument values:
4294 This value causes the @code{--sources} option to behave in the same way
4295 as the @code{--source} option.
4298 Build the source derivations of all packages, including any source that
4299 might be listed as @code{inputs}. This is the default value.
4302 $ guix build --sources tzdata
4303 The following derivations will be built:
4304 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
4305 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
4309 Build the source derivations of all packages, as well of all transitive
4310 inputs to the packages. This can be used e.g. to
4311 prefetch package source for later offline building.
4314 $ guix build --sources=transitive tzdata
4315 The following derivations will be built:
4316 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
4317 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
4318 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
4319 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
4320 /gnu/store/@dots{}-make-4.1.tar.xz.drv
4321 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
4327 @item --system=@var{system}
4328 @itemx -s @var{system}
4329 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
4330 the system type of the build host.
4332 An example use of this is on Linux-based systems, which can emulate
4333 different personalities. For instance, passing
4334 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
4335 to build packages in a complete 32-bit environment.
4337 @item --target=@var{triplet}
4338 @cindex cross-compilation
4339 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
4340 as @code{"mips64el-linux-gnu"} (@pxref{Configuration Names, GNU
4341 configuration triplets,, configure, GNU Configure and Build System}).
4343 @anchor{build-check}
4345 @cindex determinism, checking
4346 @cindex reproducibility, checking
4347 Rebuild @var{package-or-derivation}, which are already available in the
4348 store, and raise an error if the build results are not bit-for-bit
4351 This mechanism allows you to check whether previously installed
4352 substitutes are genuine (@pxref{Substitutes}), or whether the build result
4353 of a package is deterministic. @xref{Invoking guix challenge}, for more
4354 background information and tools.
4356 When used in conjunction with @option{--keep-failed}, the differing
4357 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
4358 This makes it easy to look for differences between the two results.
4362 Return the derivation paths, not the output paths, of the given
4365 @item --root=@var{file}
4366 @itemx -r @var{file}
4367 Make @var{file} a symlink to the result, and register it as a garbage
4371 Return the build log file names or URLs for the given
4372 @var{package-or-derivation}, or raise an error if build logs are
4375 This works regardless of how packages or derivations are specified. For
4376 instance, the following invocations are equivalent:
4379 guix build --log-file `guix build -d guile`
4380 guix build --log-file `guix build guile`
4381 guix build --log-file guile
4382 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
4385 If a log is unavailable locally, and unless @code{--no-substitutes} is
4386 passed, the command looks for a corresponding log on one of the
4387 substitute servers (as specified with @code{--substitute-urls}.)
4389 So for instance, imagine you want to see the build log of GDB on MIPS,
4390 but you are actually on an @code{x86_64} machine:
4393 $ guix build --log-file gdb -s mips64el-linux
4394 https://hydra.gnu.org/log/@dots{}-gdb-7.10
4397 You can freely access a huge library of build logs!
4401 @node Invoking guix edit
4402 @section Invoking @command{guix edit}
4404 @cindex package definition, editing
4405 So many packages, so many source files! The @command{guix edit} command
4406 facilitates the life of packagers by pointing their editor at the source
4407 file containing the definition of the specified packages. For instance:
4410 guix edit gcc@@4.9 vim
4414 launches the program specified in the @code{VISUAL} or in the
4415 @code{EDITOR} environment variable to edit the recipe of GCC@tie{}4.9.3
4418 If you are using Emacs, note that the Emacs user interface provides the
4419 @kbd{M-x guix-edit} command and a similar functionality in the ``package
4420 info'' and ``package list'' buffers created by the @kbd{M-x
4421 guix-search-by-name} and similar commands (@pxref{Emacs Commands}).
4424 @node Invoking guix download
4425 @section Invoking @command{guix download}
4427 When writing a package definition, developers typically need to download
4428 a source tarball, compute its SHA256 hash, and write that
4429 hash in the package definition (@pxref{Defining Packages}). The
4430 @command{guix download} tool helps with this task: it downloads a file
4431 from the given URI, adds it to the store, and prints both its file name
4432 in the store and its SHA256 hash.
4434 The fact that the downloaded file is added to the store saves bandwidth:
4435 when the developer eventually tries to build the newly defined package
4436 with @command{guix build}, the source tarball will not have to be
4437 downloaded again because it is already in the store. It is also a
4438 convenient way to temporarily stash files, which may be deleted
4439 eventually (@pxref{Invoking guix gc}).
4441 The @command{guix download} command supports the same URIs as used in
4442 package definitions. In particular, it supports @code{mirror://} URIs.
4443 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
4444 Guile bindings for GnuTLS are available in the user's environment; when
4445 they are not available, an error is raised. @xref{Guile Preparations,
4446 how to install the GnuTLS bindings for Guile,, gnutls-guile,
4447 GnuTLS-Guile}, for more information.
4449 The following option is available:
4452 @item --format=@var{fmt}
4454 Write the hash in the format specified by @var{fmt}. For more
4455 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
4458 @node Invoking guix hash
4459 @section Invoking @command{guix hash}
4461 The @command{guix hash} command computes the SHA256 hash of a file.
4462 It is primarily a convenience tool for anyone contributing to the
4463 distribution: it computes the cryptographic hash of a file, which can be
4464 used in the definition of a package (@pxref{Defining Packages}).
4466 The general syntax is:
4469 guix hash @var{option} @var{file}
4472 @command{guix hash} has the following option:
4476 @item --format=@var{fmt}
4478 Write the hash in the format specified by @var{fmt}.
4480 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
4481 (@code{hex} and @code{hexadecimal} can be used as well).
4483 If the @option{--format} option is not specified, @command{guix hash}
4484 will output the hash in @code{nix-base32}. This representation is used
4485 in the definitions of packages.
4489 Compute the hash on @var{file} recursively.
4491 In this case, the hash is computed on an archive containing @var{file},
4492 including its children if it is a directory. Some of the metadata of
4493 @var{file} is part of the archive; for instance, when @var{file} is a
4494 regular file, the hash is different depending on whether @var{file} is
4495 executable or not. Metadata such as time stamps has no impact on the
4496 hash (@pxref{Invoking guix archive}).
4497 @c FIXME: Replace xref above with xref to an ``Archive'' section when
4502 @node Invoking guix import
4503 @section Invoking @command{guix import}
4505 @cindex importing packages
4506 @cindex package import
4507 @cindex package conversion
4508 The @command{guix import} command is useful for people who would like to
4509 add a package to the distribution with as little work as
4510 possible---a legitimate demand. The command knows of a few
4511 repositories from which it can ``import'' package metadata. The result
4512 is a package definition, or a template thereof, in the format we know
4513 (@pxref{Defining Packages}).
4515 The general syntax is:
4518 guix import @var{importer} @var{options}@dots{}
4521 @var{importer} specifies the source from which to import package
4522 metadata, and @var{options} specifies a package identifier and other
4523 options specific to @var{importer}. Currently, the available
4528 Import metadata for the given GNU package. This provides a template
4529 for the latest version of that GNU package, including the hash of its
4530 source tarball, and its canonical synopsis and description.
4532 Additional information such as the package dependencies and its
4533 license needs to be figured out manually.
4535 For example, the following command returns a package definition for
4539 guix import gnu hello
4542 Specific command-line options are:
4545 @item --key-download=@var{policy}
4546 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
4547 keys when verifying the package signature. @xref{Invoking guix
4548 refresh, @code{--key-download}}.
4553 Import metadata from the @uref{https://pypi.python.org/, Python Package
4554 Index}@footnote{This functionality requires Guile-JSON to be installed.
4555 @xref{Requirements}.}. Information is taken from the JSON-formatted
4556 description available at @code{pypi.python.org} and usually includes all
4557 the relevant information, including package dependencies. For maximum
4558 efficiency, it is recommended to install the @command{unzip} utility, so
4559 that the importer can unzip Python wheels and gather data from them.
4561 The command below imports metadata for the @code{itsdangerous} Python
4565 guix import pypi itsdangerous
4570 Import metadata from @uref{https://rubygems.org/,
4571 RubyGems}@footnote{This functionality requires Guile-JSON to be
4572 installed. @xref{Requirements}.}. Information is taken from the
4573 JSON-formatted description available at @code{rubygems.org} and includes
4574 most relevant information, including runtime dependencies. There are
4575 some caveats, however. The metadata doesn't distinguish between
4576 synopses and descriptions, so the same string is used for both fields.
4577 Additionally, the details of non-Ruby dependencies required to build
4578 native extensions is unavailable and left as an exercise to the
4581 The command below imports metadata for the @code{rails} Ruby package:
4584 guix import gem rails
4589 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
4590 functionality requires Guile-JSON to be installed.
4591 @xref{Requirements}.}.
4592 Information is taken from the JSON-formatted metadata provided through
4593 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
4594 relevant information, such as module dependencies. License information
4595 should be checked closely. If Perl is available in the store, then the
4596 @code{corelist} utility will be used to filter core modules out of the
4597 list of dependencies.
4599 The command command below imports metadata for the @code{Acme::Boolean}
4603 guix import cpan Acme::Boolean
4608 @cindex Bioconductor
4609 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
4610 central repository for the @uref{http://r-project.org, GNU@tie{}R
4611 statistical and graphical environment}.
4613 Information is extracted from the @code{DESCRIPTION} file of the package.
4615 The command command below imports metadata for the @code{Cairo}
4619 guix import cran Cairo
4622 When @code{--archive=bioconductor} is added, metadata is imported from
4623 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
4624 packages for for the analysis and comprehension of high-throughput
4625 genomic data in bioinformatics.
4627 Information is extracted from the @code{DESCRIPTION} file of a package
4628 published on the web interface of the Bioconductor SVN repository.
4630 The command below imports metadata for the @code{GenomicRanges}
4634 guix import cran --archive=bioconductor GenomicRanges
4638 Import metadata from a local copy of the source of the
4639 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
4640 relies on the @command{nix-instantiate} command of
4641 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
4642 typically written in a mixture of Nix-language and Bash code. This
4643 command only imports the high-level package structure that is written in
4644 the Nix language. It normally includes all the basic fields of a
4647 When importing a GNU package, the synopsis and descriptions are replaced
4648 by their canonical upstream variant.
4650 Usually, you will first need to do:
4653 export NIX_REMOTE=daemon
4657 so that @command{nix-instantiate} does not try to open the Nix database.
4659 As an example, the command below imports the package definition of
4660 LibreOffice (more precisely, it imports the definition of the package
4661 bound to the @code{libreoffice} top-level attribute):
4664 guix import nix ~/path/to/nixpkgs libreoffice
4669 Import metadata from the Haskell community's central package archive
4670 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
4671 Cabal files and includes all the relevant information, including package
4674 Specific command-line options are:
4679 Read a Cabal file from standard input.
4680 @item --no-test-dependencies
4682 Do not include dependencies required only by the test suites.
4683 @item --cabal-environment=@var{alist}
4684 @itemx -e @var{alist}
4685 @var{alist} is a Scheme alist defining the environment in which the
4686 Cabal conditionals are evaluated. The accepted keys are: @code{os},
4687 @code{arch}, @code{impl} and a string representing the name of a flag.
4688 The value associated with a flag has to be either the symbol
4689 @code{true} or @code{false}. The value associated with other keys
4690 has to conform to the Cabal file format definition. The default value
4691 associated with the keys @code{os}, @code{arch} and @code{impl} is
4692 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
4695 The command below imports metadata for the latest version of the
4696 @code{HTTP} Haskell package without including test dependencies and
4697 specifying the value of the flag @samp{network-uri} as @code{false}:
4700 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
4703 A specific package version may optionally be specified by following the
4704 package name by an at-sign and a version number as in the following example:
4707 guix import hackage mtl@@2.1.3.1
4712 Import metadata from an Emacs Lisp Package Archive (ELPA) package
4713 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
4715 Specific command-line options are:
4718 @item --archive=@var{repo}
4719 @itemx -a @var{repo}
4720 @var{repo} identifies the archive repository from which to retrieve the
4721 information. Currently the supported repositories and their identifiers
4725 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
4726 identifier. This is the default.
4729 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
4730 @code{melpa-stable} identifier.
4733 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
4739 The structure of the @command{guix import} code is modular. It would be
4740 useful to have more importers for other package formats, and your help
4741 is welcome here (@pxref{Contributing}).
4743 @node Invoking guix refresh
4744 @section Invoking @command{guix refresh}
4746 The primary audience of the @command{guix refresh} command is developers
4747 of the GNU software distribution. By default, it reports any packages
4748 provided by the distribution that are outdated compared to the latest
4749 upstream version, like this:
4753 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
4754 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
4757 It does so by browsing the FTP directory of each package and determining
4758 the highest version number of the source tarballs therein. The command
4759 knows how to update specific types of packages: GNU packages, ELPA
4760 packages, etc.---see the documentation for @option{--type} below. The
4761 are many packages, though, for which it lacks a method to determine
4762 whether a new upstream release is available. However, the mechanism is
4763 extensible, so feel free to get in touch with us to add a new method!
4765 When passed @code{--update}, it modifies distribution source files to
4766 update the version numbers and source tarball hashes of those package
4767 recipes (@pxref{Defining Packages}). This is achieved by downloading
4768 each package's latest source tarball and its associated OpenPGP
4769 signature, authenticating the downloaded tarball against its signature
4770 using @command{gpg}, and finally computing its hash. When the public
4771 key used to sign the tarball is missing from the user's keyring, an
4772 attempt is made to automatically retrieve it from a public key server;
4773 when this is successful, the key is added to the user's keyring; otherwise,
4774 @command{guix refresh} reports an error.
4776 The following options are supported:
4780 @item --expression=@var{expr}
4781 @itemx -e @var{expr}
4782 Consider the package @var{expr} evaluates to.
4784 This is useful to precisely refer to a package, as in this example:
4787 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
4790 This command lists the dependents of the ``final'' libc (essentially all
4795 Update distribution source files (package recipes) in place. This is
4796 usually run from a checkout of the Guix source tree (@pxref{Running
4797 Guix Before It Is Installed}):
4800 $ ./pre-inst-env guix refresh -s non-core
4803 @xref{Defining Packages}, for more information on package definitions.
4805 @item --select=[@var{subset}]
4806 @itemx -s @var{subset}
4807 Select all the packages in @var{subset}, one of @code{core} or
4810 The @code{core} subset refers to all the packages at the core of the
4811 distribution---i.e., packages that are used to build ``everything
4812 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
4813 changing one of these packages in the distribution entails a rebuild of
4814 all the others. Thus, such updates are an inconvenience to users in
4815 terms of build time or bandwidth used to achieve the upgrade.
4817 The @code{non-core} subset refers to the remaining packages. It is
4818 typically useful in cases where an update of the core packages would be
4821 @item --type=@var{updater}
4822 @itemx -t @var{updater}
4823 Select only packages handled by @var{updater} (may be a comma-separated
4824 list of updaters). Currently, @var{updater} may be one of:
4828 the updater for GNU packages;
4830 the updater for GNOME packages;
4832 the updater for X.org packages;
4834 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
4836 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
4838 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
4840 the updater for @uref{https://pypi.python.org, PyPI} packages.
4842 the updater for @uref{https://rubygems.org, RubyGems} packages.
4844 the updater for @uref{https://github.com, GitHub} packages.
4846 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
4849 For instance, the following command only checks for updates of Emacs
4850 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
4853 $ guix refresh --type=elpa,cran
4854 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
4855 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
4860 In addition, @command{guix refresh} can be passed one or more package
4861 names, as in this example:
4864 $ ./pre-inst-env guix refresh -u emacs idutils gcc-4.8.4
4868 The command above specifically updates the @code{emacs} and
4869 @code{idutils} packages. The @code{--select} option would have no
4870 effect in this case.
4872 When considering whether to upgrade a package, it is sometimes
4873 convenient to know which packages would be affected by the upgrade and
4874 should be checked for compatibility. For this the following option may
4875 be used when passing @command{guix refresh} one or more package names:
4879 @item --list-updaters
4881 List available updaters and exit (see @option{--type} above.)
4883 @item --list-dependent
4885 List top-level dependent packages that would need to be rebuilt as a
4886 result of upgrading one or more packages.
4890 Be aware that the @code{--list-dependent} option only
4891 @emph{approximates} the rebuilds that would be required as a result of
4892 an upgrade. More rebuilds might be required under some circumstances.
4895 $ guix refresh --list-dependent flex
4896 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
4897 hop-2.4.0 geiser-0.4 notmuch-0.18 mu-0.9.9.5 cflow-1.4 idutils-4.6 @dots{}
4900 The command above lists a set of packages that could be built to check
4901 for compatibility with an upgraded @code{flex} package.
4903 The following options can be used to customize GnuPG operation:
4907 @item --gpg=@var{command}
4908 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
4909 for in @code{$PATH}.
4911 @item --key-download=@var{policy}
4912 Handle missing OpenPGP keys according to @var{policy}, which may be one
4917 Always download missing OpenPGP keys from the key server, and add them
4918 to the user's GnuPG keyring.
4921 Never try to download missing OpenPGP keys. Instead just bail out.
4924 When a package signed with an unknown OpenPGP key is encountered, ask
4925 the user whether to download it or not. This is the default behavior.
4928 @item --key-server=@var{host}
4929 Use @var{host} as the OpenPGP key server when importing a public key.
4933 The @code{github} updater uses the
4934 @uref{https://developer.github.com/v3/, GitHub API} to query for new
4935 releases. When used repeatedly e.g. when refreshing all packages,
4936 GitHub will eventually refuse to answer any further API requests. By
4937 default 60 API requests per hour are allowed, and a full refresh on all
4938 GitHub packages in Guix requires more than this. Authentication with
4939 GitHub through the use of an API token alleviates these limits. To use
4940 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
4941 token procured from @uref{https://github.com/settings/tokens} or
4945 @node Invoking guix lint
4946 @section Invoking @command{guix lint}
4947 The @command{guix lint} command is meant to help package developers avoid
4948 common errors and use a consistent style. It runs a number of checks on
4949 a given set of packages in order to find common mistakes in their
4950 definitions. Available @dfn{checkers} include (see
4951 @code{--list-checkers} for a complete list):
4956 Validate certain typographical and stylistic rules about package
4957 descriptions and synopses.
4959 @item inputs-should-be-native
4960 Identify inputs that should most likely be native inputs.
4964 @itemx source-file-name
4965 Probe @code{home-page} and @code{source} URLs and report those that are
4966 invalid. Check that the source file name is meaningful, e.g. is not
4967 just a version number or ``git-checkout'', without a declared
4968 @code{file-name} (@pxref{origin Reference}).
4971 @cindex security vulnerabilities
4972 @cindex CVE, Common Vulnerabilities and Exposures
4973 Report known vulnerabilities found in the Common Vulnerabilities and
4974 Exposures (CVE) databases of the current and past year
4975 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
4978 To view information about a particular vulnerability, visit pages such as:
4982 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
4984 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
4988 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
4989 @code{CVE-2015-7554}.
4991 Package developers can specify in package recipes the
4992 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
4993 name and version of the package when they differ from the name that Guix
4994 uses, as in this example:
5000 ;; CPE calls this package "grub2".
5001 (properties '((cpe-name . "grub2"))))
5005 Warn about obvious source code formatting issues: trailing white space,
5006 use of tabulations, etc.
5009 The general syntax is:
5012 guix lint @var{options} @var{package}@dots{}
5015 If no package is given on the command line, then all packages are checked.
5016 The @var{options} may be zero or more of the following:
5019 @item --list-checkers
5021 List and describe all the available checkers that will be run on packages
5026 Only enable the checkers specified in a comma-separated list using the
5027 names returned by @code{--list-checkers}.
5031 @node Invoking guix size
5032 @section Invoking @command{guix size}
5034 The @command{guix size} command helps package developers profile the
5035 disk usage of packages. It is easy to overlook the impact of an
5036 additional dependency added to a package, or the impact of using a
5037 single output for a package that could easily be split (@pxref{Packages
5038 with Multiple Outputs}). Such are the typical issues that
5039 @command{guix size} can highlight.
5041 The command can be passed a package specification such as @code{gcc-4.8}
5042 or @code{guile:debug}, or a file name in the store. Consider this
5046 $ guix size coreutils
5047 store item total self
5048 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
5049 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
5050 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
5051 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
5052 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
5053 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
5057 The store items listed here constitute the @dfn{transitive closure} of
5058 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
5059 would be returned by:
5062 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
5065 Here the output shows three columns next to store items. The first column,
5066 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
5067 the store item---that is, its own size plus the size of all its
5068 dependencies. The next column, labeled ``self'', shows the size of the
5069 item itself. The last column shows the ratio of the size of the item
5070 itself to the space occupied by all the items listed here.
5072 In this example, we see that the closure of Coreutils weighs in at
5073 70@tie{}MiB, half of which is taken by libc. (That libc represents a
5074 large fraction of the closure is not a problem @i{per se} because it is
5075 always available on the system anyway.)
5077 When the package passed to @command{guix size} is available in the
5078 store, @command{guix size} queries the daemon to determine its
5079 dependencies, and measures its size in the store, similar to @command{du
5080 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
5083 When the given package is @emph{not} in the store, @command{guix size}
5084 reports information based on the available substitutes
5085 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
5086 store items that are not even on disk, only available remotely.
5088 You can also specify several package names:
5091 $ guix size coreutils grep sed bash
5092 store item total self
5093 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
5094 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
5095 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
5096 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
5102 In this example we see that the combination of the four packages takes
5103 102.3@tie{}MiB in total, which is much less than the sum of each closure
5104 since they have a lot of dependencies in common.
5106 The available options are:
5110 @item --substitute-urls=@var{urls}
5111 Use substitute information from @var{urls}.
5112 @xref{client-substitute-urls, the same option for @code{guix build}}.
5114 @item --map-file=@var{file}
5115 Write a graphical map of disk usage in PNG format to @var{file}.
5117 For the example above, the map looks like this:
5119 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
5120 produced by @command{guix size}}
5122 This option requires that
5123 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
5124 installed and visible in Guile's module search path. When that is not
5125 the case, @command{guix size} fails as it tries to load it.
5127 @item --system=@var{system}
5128 @itemx -s @var{system}
5129 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
5133 @node Invoking guix graph
5134 @section Invoking @command{guix graph}
5137 Packages and their dependencies form a @dfn{graph}, specifically a
5138 directed acyclic graph (DAG). It can quickly become difficult to have a
5139 mental model of the package DAG, so the @command{guix graph} command
5140 provides a visual representation of the DAG. @command{guix graph}
5141 emits a DAG representation in the input format of
5142 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
5143 directly to the @command{dot} command of Graphviz. The general
5147 guix graph @var{options} @var{package}@dots{}
5150 For example, the following command generates a PDF file representing the
5151 package DAG for the GNU@tie{}Core Utilities, showing its build-time
5155 guix graph coreutils | dot -Tpdf > dag.pdf
5158 The output looks like this:
5160 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
5162 Nice little graph, no?
5164 But there is more than one graph! The one above is concise: it is the
5165 graph of package objects, omitting implicit inputs such as GCC, libc,
5166 grep, etc. It is often useful to have such a concise graph, but
5167 sometimes one may want to see more details. @command{guix graph} supports
5168 several types of graphs, allowing you to choose the level of detail:
5172 This is the default type used in the example above. It shows the DAG of
5173 package objects, excluding implicit dependencies. It is concise, but
5174 filters out many details.
5177 This is the package DAG, @emph{including} implicit inputs.
5179 For instance, the following command:
5182 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
5185 ... yields this bigger graph:
5187 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
5189 At the bottom of the graph, we see all the implicit inputs of
5190 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
5192 Now, note that the dependencies of these implicit inputs---that is, the
5193 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
5194 here, for conciseness.
5197 Similar to @code{bag-emerged}, but this time including all the bootstrap
5200 @item bag-with-origins
5201 Similar to @code{bag}, but also showing origins and their dependencies.
5204 This is the most detailed representation: It shows the DAG of
5205 derivations (@pxref{Derivations}) and plain store items. Compared to
5206 the above representation, many additional nodes are visible, including
5207 build scripts, patches, Guile modules, etc.
5209 For this type of graph, it is also possible to pass a @file{.drv} file
5210 name instead of a package name, as in:
5213 guix graph -t derivation `guix system build -d my-config.scm`
5217 All the types above correspond to @emph{build-time dependencies}. The
5218 following graph type represents the @emph{run-time dependencies}:
5222 This is the graph of @dfn{references} of a package output, as returned
5223 by @command{guix gc --references} (@pxref{Invoking guix gc}).
5225 If the given package output is not available in the store, @command{guix
5226 graph} attempts to obtain dependency information from substitutes.
5228 Here you can also pass a store file name instead of a package name. For
5229 example, the command below produces the reference graph of your profile
5230 (which can be big!):
5233 guix graph -t references `readlink -f ~/.guix-profile`
5237 The available options are the following:
5240 @item --type=@var{type}
5241 @itemx -t @var{type}
5242 Produce a graph output of @var{type}, where @var{type} must be one of
5243 the values listed above.
5246 List the supported graph types.
5248 @item --expression=@var{expr}
5249 @itemx -e @var{expr}
5250 Consider the package @var{expr} evaluates to.
5252 This is useful to precisely refer to a package, as in this example:
5255 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
5260 @node Invoking guix environment
5261 @section Invoking @command{guix environment}
5263 @cindex reproducible build environments
5264 @cindex development environments
5265 The purpose of @command{guix environment} is to assist hackers in
5266 creating reproducible development environments without polluting their
5267 package profile. The @command{guix environment} tool takes one or more
5268 packages, builds all of their inputs, and creates a shell
5269 environment to use them.
5271 The general syntax is:
5274 guix environment @var{options} @var{package}@dots{}
5277 The following example spawns a new shell set up for the development of
5281 guix environment guile
5284 If the needed dependencies are not built yet, @command{guix environment}
5285 automatically builds them. The environment of the new shell is an augmented
5286 version of the environment that @command{guix environment} was run in.
5287 It contains the necessary search paths for building the given package
5288 added to the existing environment variables. To create a ``pure''
5289 environment, in which the original environment variables have been unset,
5290 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
5291 environment variables such as @code{PATH} in their @file{~/.bashrc}
5292 file. As a consequence, when @code{guix environment} launches it, Bash
5293 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
5294 environment variables. It is an error to define such environment
5295 variables in @file{.bashrc}; instead, they should be defined in
5296 @file{.bash_profile}, which is sourced only by log-in shells.
5297 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
5298 details on Bash start-up files.}.
5300 @vindex GUIX_ENVIRONMENT
5301 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
5302 variable in the shell it spawns. This allows users to, say, define a
5303 specific prompt for development environments in their @file{.bashrc}
5304 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
5307 if [ -n "$GUIX_ENVIRONMENT" ]
5309 export PS1="\u@@\h \w [dev]\$ "
5313 Additionally, more than one package may be specified, in which case the
5314 union of the inputs for the given packages are used. For example, the
5315 command below spawns a shell where all of the dependencies of both Guile
5316 and Emacs are available:
5319 guix environment guile emacs
5322 Sometimes an interactive shell session is not desired. An arbitrary
5323 command may be invoked by placing the @code{--} token to separate the
5324 command from the rest of the arguments:
5327 guix environment guile -- make -j4
5330 In other situations, it is more convenient to specify the list of
5331 packages needed in the environment. For example, the following command
5332 runs @command{python} from an environment containing Python@tie{}2.7 and
5336 guix environment --ad-hoc python2-numpy python-2.7 -- python
5339 Furthermore, one might want the dependencies of a package and also some
5340 additional packages that are not build-time or runtime dependencies, but
5341 are useful when developing nonetheless. Because of this, the
5342 @code{--ad-hoc} flag is positional. Packages appearing before
5343 @code{--ad-hoc} are interpreted as packages whose dependencies will be
5344 added to the environment. Packages appearing after are interpreted as
5345 packages that will be added to the environment directly. For example,
5346 the following command creates a Guix development environment that
5347 additionally includes Git and strace:
5350 guix environment guix --ad-hoc git strace
5353 Sometimes it is desirable to isolate the environment as much as
5354 possible, for maximal purity and reproducibility. In particular, when
5355 using Guix on a host distro that is not GuixSD, it is desirable to
5356 prevent access to @file{/usr/bin} and other system-wide resources from
5357 the development environment. For example, the following command spawns
5358 a Guile REPL in a ``container'' where only the store and the current
5359 working directory are mounted:
5362 guix environment --ad-hoc --container guile -- guile
5366 The @code{--container} option requires Linux-libre 3.19 or newer.
5369 The available options are summarized below.
5372 @item --expression=@var{expr}
5373 @itemx -e @var{expr}
5374 Create an environment for the package or list of packages that
5375 @var{expr} evaluates to.
5377 For example, running:
5380 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
5383 starts a shell with the environment for this specific variant of the
5389 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
5392 starts a shell with all the GuixSD base packages available.
5394 The above commands only the use default output of the given packages.
5395 To select other outputs, two element tuples can be specified:
5398 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
5401 @item --load=@var{file}
5402 @itemx -l @var{file}
5403 Create an environment for the package or list of packages that the code
5404 within @var{file} evaluates to.
5406 As an example, @var{file} might contain a definition like this
5407 (@pxref{Defining Packages}):
5410 @verbatiminclude environment-gdb.scm
5414 Include all specified packages in the resulting environment, as if an
5415 @i{ad hoc} package were defined with them as inputs. This option is
5416 useful for quickly creating an environment without having to write a
5417 package expression to contain the desired inputs.
5419 For instance, the command:
5422 guix environment --ad-hoc guile guile-sdl -- guile
5425 runs @command{guile} in an environment where Guile and Guile-SDL are
5428 Note that this example implicitly asks for the default output of
5429 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
5430 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
5431 of @code{glib} (@pxref{Packages with Multiple Outputs}).
5433 This option may be composed with the default behavior of @command{guix
5434 environment}. Packages appearing before @code{--ad-hoc} are interpreted
5435 as packages whose dependencies will be added to the environment, the
5436 default behavior. Packages appearing after are interpreted as packages
5437 that will be added to the environment directly.
5440 Unset existing environment variables when building the new environment.
5441 This has the effect of creating an environment in which search paths
5442 only contain package inputs.
5444 @item --search-paths
5445 Display the environment variable definitions that make up the
5448 @item --system=@var{system}
5449 @itemx -s @var{system}
5450 Attempt to build for @var{system}---e.g., @code{i686-linux}.
5455 Run @var{command} within an isolated container. The current working
5456 directory outside the container is mapped inside the container.
5457 Additionally, a dummy home directory is created that matches the current
5458 user's home directory, and @file{/etc/passwd} is configured accordingly.
5459 The spawned process runs as the current user outside the container, but
5460 has root privileges in the context of the container.
5464 For containers, share the network namespace with the host system.
5465 Containers created without this flag only have access to the loopback
5468 @item --expose=@var{source}[=@var{target}]
5469 For containers, expose the file system @var{source} from the host system
5470 as the read-only file system @var{target} within the container. If
5471 @var{target} is not specified, @var{source} is used as the target mount
5472 point in the container.
5474 The example below spawns a Guile REPL in a container in which the user's
5475 home directory is accessible read-only via the @file{/exchange}
5479 guix environment --container --expose=$HOME=/exchange guile -- guile
5482 @item --share=@var{source}[=@var{target}]
5483 For containers, share the file system @var{source} from the host system
5484 as the writable file system @var{target} within the container. If
5485 @var{target} is not specified, @var{source} is used as the target mount
5486 point in the container.
5488 The example below spawns a Guile REPL in a container in which the user's
5489 home directory is accessible for both reading and writing via the
5490 @file{/exchange} directory:
5493 guix environment --container --share=$HOME=/exchange guile -- guile
5497 It also supports all of the common build options that @command{guix
5498 build} supports (@pxref{Common Build Options}).
5500 @node Invoking guix publish
5501 @section Invoking @command{guix publish}
5503 The purpose of @command{guix publish} is to enable users to easily share
5504 their store with others, who can then use it as a substitute server
5505 (@pxref{Substitutes}).
5507 When @command{guix publish} runs, it spawns an HTTP server which allows
5508 anyone with network access to obtain substitutes from it. This means
5509 that any machine running Guix can also act as if it were a build farm,
5510 since the HTTP interface is compatible with Hydra, the software behind
5511 the @code{hydra.gnu.org} build farm.
5513 For security, each substitute is signed, allowing recipients to check
5514 their authenticity and integrity (@pxref{Substitutes}). Because
5515 @command{guix publish} uses the signing key of the system, which is only
5516 readable by the system administrator, it must be started as root; the
5517 @code{--user} option makes it drop root privileges early on.
5519 The signing key pair must be generated before @command{guix publish} is
5520 launched, using @command{guix archive --generate-key} (@pxref{Invoking
5523 The general syntax is:
5526 guix publish @var{options}@dots{}
5529 Running @command{guix publish} without any additional arguments will
5530 spawn an HTTP server on port 8080:
5536 Once a publishing server has been authorized (@pxref{Invoking guix
5537 archive}), the daemon may download substitutes from it:
5540 guix-daemon --substitute-urls=http://example.org:8080
5543 The following options are available:
5546 @item --port=@var{port}
5547 @itemx -p @var{port}
5548 Listen for HTTP requests on @var{port}.
5550 @item --listen=@var{host}
5551 Listen on the network interface for @var{host}. The default is to
5552 accept connections from any interface.
5554 @item --user=@var{user}
5555 @itemx -u @var{user}
5556 Change privileges to @var{user} as soon as possible---i.e., once the
5557 server socket is open and the signing key has been read.
5559 @item --ttl=@var{ttl}
5560 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
5561 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
5562 days, @code{1m} means 1 month, and so on.
5564 This allows the user's Guix to keep substitute information in cache for
5565 @var{ttl}. However, note that @code{guix publish} does not itself
5566 guarantee that the store items it provides will indeed remain available
5567 for as long as @var{ttl}.
5569 @item --repl[=@var{port}]
5570 @itemx -r [@var{port}]
5571 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
5572 Reference Manual}) on @var{port} (37146 by default). This is used
5573 primarily for debugging a running @command{guix publish} server.
5576 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
5577 add a call to @code{guix-publish-service} in the @code{services} field
5578 of the @code{operating-system} declaration (@pxref{guix-publish-service,
5579 @code{guix-publish-service}}).
5582 @node Invoking guix challenge
5583 @section Invoking @command{guix challenge}
5585 @cindex reproducible builds
5586 @cindex verifiable builds
5588 Do the binaries provided by this server really correspond to the source
5589 code it claims to build? Is a package build process deterministic?
5590 These are the questions the @command{guix challenge} command attempts to
5593 The former is obviously an important question: Before using a substitute
5594 server (@pxref{Substitutes}), one had better @emph{verify} that it
5595 provides the right binaries, and thus @emph{challenge} it. The latter
5596 is what enables the former: If package builds are deterministic, then
5597 independent builds of the package should yield the exact same result,
5598 bit for bit; if a server provides a binary different from the one
5599 obtained locally, it may be either corrupt or malicious.
5601 We know that the hash that shows up in @file{/gnu/store} file names is
5602 the hash of all the inputs of the process that built the file or
5603 directory---compilers, libraries, build scripts,
5604 etc. (@pxref{Introduction}). Assuming deterministic build processes,
5605 one store file name should map to exactly one build output.
5606 @command{guix challenge} checks whether there is, indeed, a single
5607 mapping by comparing the build outputs of several independent builds of
5608 any given store item.
5610 The command output looks like this:
5613 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
5614 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
5615 updating list of substitutes from 'https://guix.example.org'... 100.0%
5616 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
5617 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
5618 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
5619 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
5620 /gnu/store/@dots{}-git-2.5.0 contents differ:
5621 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
5622 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
5623 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
5624 /gnu/store/@dots{}-pius-2.1.1 contents differ:
5625 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
5626 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
5627 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
5631 In this example, @command{guix challenge} first scans the store to
5632 determine the set of locally-built derivations---as opposed to store
5633 items that were downloaded from a substitute server---and then queries
5634 all the substitute servers. It then reports those store items for which
5635 the servers obtained a result different from the local build.
5637 @cindex non-determinism, in package builds
5638 As an example, @code{guix.example.org} always gets a different answer.
5639 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
5640 case of Git. This might indicate that the build process of Git is
5641 non-deterministic, meaning that its output varies as a function of
5642 various things that Guix does not fully control, in spite of building
5643 packages in isolated environments (@pxref{Features}). Most common
5644 sources of non-determinism include the addition of timestamps in build
5645 results, the inclusion of random numbers, and directory listings sorted
5646 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
5649 To find out what is wrong with this Git binary, we can do something along
5650 these lines (@pxref{Invoking guix archive}):
5653 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
5654 | guix archive -x /tmp/git
5655 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
5658 This command shows the difference between the files resulting from the
5659 local build, and the files resulting from the build on
5660 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
5661 diffutils, Comparing and Merging Files}). The @command{diff} command
5662 works great for text files. When binary files differ, a better option
5663 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
5664 visualize differences for all kinds of files.
5666 Once you have done that work, you can tell whether the differences are due
5667 to a non-deterministic build process or to a malicious server. We try
5668 hard to remove sources of non-determinism in packages to make it easier
5669 to verify substitutes, but of course, this is a process that
5670 involves not just Guix, but a large part of the free software community.
5671 In the meantime, @command{guix challenge} is one tool to help address
5674 If you are writing packages for Guix, you are encouraged to check
5675 whether @code{hydra.gnu.org} and other substitute servers obtain the
5676 same build result as you did with:
5679 $ guix challenge @var{package}
5683 where @var{package} is a package specification such as
5684 @code{guile@@2.0} or @code{glibc:debug}.
5686 The general syntax is:
5689 guix challenge @var{options} [@var{packages}@dots{}]
5692 When a difference is found between the hash of a locally-built item and
5693 that of a server-provided substitute, or among substitutes provided by
5694 different servers, the command displays it as in the example above and
5695 its exit code is 2 (other non-zero exit codes denote other kinds of
5698 The one option that matters is:
5702 @item --substitute-urls=@var{urls}
5703 Consider @var{urls} the whitespace-separated list of substitute source
5709 @node Invoking guix container
5710 @section Invoking @command{guix container}
5714 As of version @value{VERSION}, this tool is experimental. The interface
5715 is subject to radical change in the future.
5718 The purpose of @command{guix container} is to manipulate processes
5719 running within an isolated environment, commonly known as a
5720 ``container'', typically created by the @command{guix environment}
5721 (@pxref{Invoking guix environment}) and @command{guix system container}
5722 (@pxref{Invoking guix system}) commands.
5724 The general syntax is:
5727 guix container @var{action} @var{options}@dots{}
5730 @var{action} specifies the operation to perform with a container, and
5731 @var{options} specifies the context-specific arguments for the action.
5733 The following actions are available:
5737 Execute a command within the context of a running container.
5742 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
5745 @var{pid} specifies the process ID of the running container.
5746 @var{program} specifies an executable file name within the root file
5747 system of the container. @var{arguments} are the additional options that
5748 will be passed to @var{program}.
5750 The following command launches an interactive login shell inside a
5751 GuixSD container, started by @command{guix system container}, and whose
5755 guix container exec 9001 /run/current-system/profile/bin/bash --login
5758 Note that the @var{pid} cannot be the parent process of a container. It
5759 must be PID 1 of the container or one of its child processes.
5763 @c *********************************************************************
5764 @node GNU Distribution
5765 @chapter GNU Distribution
5767 @cindex Guix System Distribution
5769 Guix comes with a distribution of the GNU system consisting entirely of
5770 free software@footnote{The term ``free'' here refers to the
5771 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
5772 users of that software}.}. The
5773 distribution can be installed on its own (@pxref{System Installation}),
5774 but it is also possible to install Guix as a package manager on top of
5775 an installed GNU/Linux system (@pxref{Installation}). To distinguish
5776 between the two, we refer to the standalone distribution as the Guix
5777 System Distribution, or GuixSD.
5779 The distribution provides core GNU packages such as GNU libc, GCC, and
5780 Binutils, as well as many GNU and non-GNU applications. The complete
5781 list of available packages can be browsed
5782 @url{http://www.gnu.org/software/guix/packages,on-line} or by
5783 running @command{guix package} (@pxref{Invoking guix package}):
5786 guix package --list-available
5789 Our goal is to provide a practical 100% free software distribution of
5790 Linux-based and other variants of GNU, with a focus on the promotion and
5791 tight integration of GNU components, and an emphasis on programs and
5792 tools that help users exert that freedom.
5794 Packages are currently available on the following platforms:
5799 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
5802 Intel 32-bit architecture (IA32), Linux-Libre kernel;
5805 ARMv7-A architecture with hard float, Thumb-2 and NEON,
5806 using the EABI hard-float application binary interface (ABI),
5807 and Linux-Libre kernel.
5809 @item mips64el-linux
5810 little-endian 64-bit MIPS processors, specifically the Loongson series,
5811 n32 ABI, and Linux-Libre kernel.
5815 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
5818 For information on porting to other architectures or kernels,
5822 * System Installation:: Installing the whole operating system.
5823 * System Configuration:: Configuring the operating system.
5824 * Installing Debugging Files:: Feeding the debugger.
5825 * Security Updates:: Deploying security fixes quickly.
5826 * Package Modules:: Packages from the programmer's viewpoint.
5827 * Packaging Guidelines:: Growing the distribution.
5828 * Bootstrapping:: GNU/Linux built from scratch.
5829 * Porting:: Targeting another platform or kernel.
5832 Building this distribution is a cooperative effort, and you are invited
5833 to join! @xref{Contributing}, for information about how you can help.
5835 @node System Installation
5836 @section System Installation
5838 @cindex Guix System Distribution
5839 This section explains how to install the Guix System Distribution
5840 on a machine. The Guix package manager can
5841 also be installed on top of a running GNU/Linux system,
5842 @pxref{Installation}.
5846 @c This paragraph is for people reading this from tty2 of the
5847 @c installation image.
5848 You are reading this documentation with an Info reader. For details on
5849 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
5850 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
5851 Info}. Hit @kbd{l} afterwards to come back here.
5853 Alternately, run @command{info info} in another tty to keep the manual
5859 * Limitations:: What you can expect.
5860 * Hardware Considerations:: Supported hardware.
5861 * USB Stick Installation:: Preparing the installation medium.
5862 * Preparing for Installation:: Networking, partitioning, etc.
5863 * Proceeding with the Installation:: The real thing.
5864 * Building the Installation Image:: How this comes to be.
5868 @subsection Limitations
5870 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
5871 not production-ready. It may contain bugs and lack important
5872 features. Thus, if you are looking for a stable production system that
5873 respects your freedom as a computer user, a good solution at this point
5874 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
5875 the more established GNU/Linux distributions}. We hope you can soon switch
5876 to the GuixSD without fear, of course. In the meantime, you can
5877 also keep using your distribution and try out the package manager on top
5878 of it (@pxref{Installation}).
5880 Before you proceed with the installation, be aware of the following
5881 noteworthy limitations applicable to version @value{VERSION}:
5885 The installation process does not include a graphical user interface and
5886 requires familiarity with GNU/Linux (see the following subsections to
5887 get a feel of what that means.)
5890 Support for the Logical Volume Manager (LVM) is missing.
5893 Few system services are currently supported out-of-the-box
5897 More than 3,200 packages are available, but you may
5898 occasionally find that a useful package is missing.
5901 GNOME, Xfce, and Enlightenment are available (@pxref{Desktop Services}),
5902 as well as a number of X11 window managers. However, some graphical
5903 applications may be missing, as well as KDE.
5906 You have been warned! But more than a disclaimer, this is an invitation
5907 to report issues (and success stories!), and to join us in improving it.
5908 @xref{Contributing}, for more info.
5911 @node Hardware Considerations
5912 @subsection Hardware Considerations
5914 @cindex hardware support on GuixSD
5915 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
5916 builds around the kernel Linux-libre, which means that only hardware for
5917 which free software drivers and firmware exist is supported. Nowadays,
5918 a wide range of off-the-shelf hardware is supported on
5919 GNU/Linux-libre---from keyboards to graphics cards to scanners and
5920 Ethernet controllers. Unfortunately, there are still areas where
5921 hardware vendors deny users control over their own computing, and such
5922 hardware is not supported on GuixSD.
5924 @cindex WiFi, hardware support
5925 One of the main areas where free drivers or firmware are lacking is WiFi
5926 devices. WiFi devices known to work include those using Atheros chips
5927 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
5928 driver, and for which free firmware exists and is available
5929 out-of-the-box on GuixSD, as part of @var{%base-firmware}
5930 (@pxref{operating-system Reference, @code{firmware}}).
5932 @cindex RYF, Respects Your Freedom
5933 The @uref{https://www.fsf.org/, Free Software Foundation} runs
5934 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
5935 certification program for hardware products that respect your freedom
5936 and your privacy and ensure that you have control over your device. We
5937 encourage you to check the list of RYF-certified devices.
5939 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
5940 web site. It contains a catalog of hardware devices with information
5941 about their support in GNU/Linux.
5944 @node USB Stick Installation
5945 @subsection USB Stick Installation
5947 An installation image for USB sticks can be downloaded from
5948 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
5949 where @var{system} is one of:
5953 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
5956 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
5959 This image contains a single partition with the tools necessary for an
5960 installation. It is meant to be copied @emph{as is} to a large-enough
5963 To copy the image to a USB stick, follow these steps:
5967 Decompress the image using the @command{xz} command:
5970 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
5974 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
5975 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
5976 copy the image with:
5979 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
5982 Access to @file{/dev/sdX} usually requires root privileges.
5985 Once this is done, you should be able to reboot the system and boot from
5986 the USB stick. The latter usually requires you to get in the BIOS' boot
5987 menu, where you can choose to boot from the USB stick.
5989 @node Preparing for Installation
5990 @subsection Preparing for Installation
5992 Once you have successfully booted the image on the USB stick, you should
5993 end up with a root prompt. Several console TTYs are configured and can
5994 be used to run commands as root. TTY2 shows this documentation,
5995 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
5996 Stand-alone GNU Info}). The installation system runs the GPM mouse
5997 daemon, which allows you to select text with the left mouse button and
5998 to paste it with the middle button.
6001 Installation requires access to the Internet so that any missing
6002 dependencies of your system configuration can be downloaded. See the
6003 ``Networking'' section below.
6006 The installation system includes many common tools needed for this task.
6007 But it is also a full-blown GuixSD system, which means that you can
6008 install additional packages, should you need it, using @command{guix
6009 package} (@pxref{Invoking guix package}).
6011 @subsubsection Keyboard Layout
6013 @cindex keyboard layout
6014 The installation image uses the US qwerty keyboard layout. If you want
6015 to change it, you can use the @command{loadkeys} command. For example,
6016 the following command selects the Dvorak keyboard layout:
6022 See the files under @file{/run/current-system/profile/share/keymaps} for
6023 a list of available keyboard layouts. Run @command{man loadkeys} for
6026 @subsubsection Networking
6028 Run the following command see what your network interfaces are called:
6035 @dots{} or, using the GNU/Linux-specific @command{ip} command:
6041 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
6042 Wired interfaces have a name starting with @samp{e}; for example, the
6043 interface corresponding to the first on-board Ethernet controller is
6044 called @samp{eno1}. Wireless interfaces have a name starting with
6045 @samp{w}, like @samp{w1p2s0}.
6048 @item Wired connection
6049 To configure a wired network run the following command, substituting
6050 @var{interface} with the name of the wired interface you want to use.
6053 ifconfig @var{interface} up
6056 @item Wireless connection
6057 To configure wireless networking, you can create a configuration file
6058 for the @command{wpa_supplicant} configuration tool (its location is not
6059 important) using one of the available text editors such as
6063 zile wpa_supplicant.conf
6066 As an example, the following stanza can go to this file and will work
6067 for many wireless networks, provided you give the actual SSID and
6068 passphrase for the network you are connecting to:
6072 ssid="@var{my-ssid}"
6074 psk="the network's secret passphrase"
6078 Start the wireless service and run it in the background with the
6079 following command (substitute @var{interface} with the name of the
6080 network interface you want to use):
6083 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
6086 Run @command{man wpa_supplicant} for more information.
6089 At this point, you need to acquire an IP address. On a network where IP
6090 addresses are automatically assigned @i{via} DHCP, you can run:
6093 dhclient -v @var{interface}
6096 Try to ping a server to see if networking is up and running:
6102 Setting up network access is almost always a requirement because the
6103 image does not contain all the software and tools that may be needed.
6105 @subsubsection Disk Partitioning
6107 Unless this has already been done, the next step is to partition, and
6108 then format the target partition(s).
6110 The installation image includes several partitioning tools, including
6111 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
6112 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
6113 the partition layout you want:
6119 Once you are done partitioning the target hard disk drive, you have to
6120 create a file system on the relevant partition(s)@footnote{Currently
6121 GuixSD pretty much assumes an ext4 file system. In particular, code
6122 that reads partition UUIDs and labels only works with ext4. This will
6123 be fixed in the future.}.
6125 Preferably, assign partitions a label so that you can easily and
6126 reliably refer to them in @code{file-system} declarations (@pxref{File
6127 Systems}). This is typically done using the @code{-L} option of
6128 @command{mkfs.ext4} and related commands. So, assuming the target root
6129 partition lives at @file{/dev/sda1}, a file system with the label
6130 @code{my-root} can be created with:
6133 mkfs.ext4 -L my-root /dev/sda1
6136 @c FIXME: Uncomment this once GRUB fully supports encrypted roots.
6137 @c A typical command sequence may be:
6141 @c @dots{} Create partitions etc.@dots{}
6142 @c # cryptsetup luksFormat /dev/sdX1
6143 @c # cryptsetup open --type luks /dev/sdX1 my-partition
6144 @c # mkfs.ext4 -L my-root /dev/mapper/my-partition
6147 In addition to e2fsprogs, the suite of tools to manipulate
6148 ext2/ext3/ext4 file systems, the installation image includes
6149 Cryptsetup/LUKS for disk encryption.
6151 Once that is done, mount the target root partition under @file{/mnt}
6152 with a command like (again, assuming @file{/dev/sda1} is the root
6156 mount /dev/sda1 /mnt
6159 Finally, if you plan to use one or more swap partitions (@pxref{Memory
6160 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
6161 sure to initialize them with @command{mkswap}. Assuming you have one
6162 swap partition on @file{/dev/sda2}, you would run:
6168 @node Proceeding with the Installation
6169 @subsection Proceeding with the Installation
6171 With the target partitions ready and the target root mounted on
6172 @file{/mnt}, we're ready to go. First, run:
6175 herd start cow-store /mnt
6178 This makes @file{/gnu/store} copy-on-write, such that packages added to it
6179 during the installation phase are written to the target disk on @file{/mnt}
6180 rather than kept in memory. This is necessary because the first phase of
6181 the @command{guix system init} command (see below) entails downloads or
6182 builds to @file{/gnu/store} which, initially, is an in-memory file system.
6184 Next, you have to edit a file and
6185 provide the declaration of the operating system to be installed. To
6186 that end, the installation system comes with two text editors: GNU nano
6187 (@pxref{Top,,, nano, GNU nano Manual}), and GNU Zile, an Emacs clone.
6188 We strongly recommend storing that file on the target root file system, say,
6189 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
6190 configuration file once you have rebooted into the newly-installed system.
6192 @xref{Using the Configuration System}, for an overview of the
6193 configuration file. The example configurations discussed in that
6194 section are available under @file{/etc/configuration} in the
6195 installation image. Thus, to get started with a system configuration
6196 providing a graphical display server (a ``desktop'' system), you can run
6197 something along these lines:
6201 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
6202 # zile /mnt/etc/config.scm
6205 You should pay attention to what your configuration file contains, and
6210 Make sure the @code{grub-configuration} form refers to the device you
6211 want to install GRUB on.
6214 Be sure that your partition labels match the value of their respective
6215 @code{device} fields in your @code{file-system} configuration, assuming
6216 your @code{file-system} configuration sets the value of @code{title} to
6220 Once you are done preparing the configuration file, the new system must
6221 be initialized (remember that the target root file system is mounted
6225 guix system init /mnt/etc/config.scm /mnt
6229 This copies all the necessary files and installs GRUB on
6230 @file{/dev/sdX}, unless you pass the @option{--no-grub} option. For
6231 more information, @pxref{Invoking guix system}. This command may trigger
6232 downloads or builds of missing packages, which can take some time.
6234 Once that command has completed---and hopefully succeeded!---you can run
6235 @command{reboot} and boot into the new system. The @code{root} password
6236 in the new system is initially empty; other users' passwords need to be
6237 initialized by running the @command{passwd} command as @code{root},
6238 unless your configuration specifies otherwise
6239 (@pxref{user-account-password, user account passwords}).
6241 Join us on @code{#guix} on the Freenode IRC network or on
6242 @file{guix-devel@@gnu.org} to share your experience---good or not so
6245 @node Building the Installation Image
6246 @subsection Building the Installation Image
6248 The installation image described above was built using the @command{guix
6249 system} command, specifically:
6251 @c FIXME: 1G is too much; see <http://bugs.gnu.org/23077>.
6253 guix system disk-image --image-size=1G gnu/system/install.scm
6256 Have a look at @file{gnu/system/install.scm} in the source tree,
6257 and see also @ref{Invoking guix system} for more information
6258 about the installation image.
6260 @node System Configuration
6261 @section System Configuration
6263 @cindex system configuration
6264 The Guix System Distribution supports a consistent whole-system configuration
6265 mechanism. By that we mean that all aspects of the global system
6266 configuration---such as the available system services, timezone and
6267 locale settings, user accounts---are declared in a single place. Such
6268 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
6270 One of the advantages of putting all the system configuration under the
6271 control of Guix is that it supports transactional system upgrades, and
6272 makes it possible to roll back to a previous system instantiation,
6273 should something go wrong with the new one (@pxref{Features}). Another
6274 advantage is that it makes it easy to replicate the exact same configuration
6275 across different machines, or at different points in time, without
6276 having to resort to additional administration tools layered on top of
6277 the own tools of the system.
6278 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
6280 This section describes this mechanism. First we focus on the system
6281 administrator's viewpoint---explaining how the system is configured and
6282 instantiated. Then we show how this mechanism can be extended, for
6283 instance to support new system services.
6286 * Using the Configuration System:: Customizing your GNU system.
6287 * operating-system Reference:: Detail of operating-system declarations.
6288 * File Systems:: Configuring file system mounts.
6289 * Mapped Devices:: Block device extra processing.
6290 * User Accounts:: Specifying user accounts.
6291 * Locales:: Language and cultural convention settings.
6292 * Services:: Specifying system services.
6293 * Setuid Programs:: Programs running with root privileges.
6294 * X.509 Certificates:: Authenticating HTTPS servers.
6295 * Name Service Switch:: Configuring libc's name service switch.
6296 * Initial RAM Disk:: Linux-Libre bootstrapping.
6297 * GRUB Configuration:: Configuring the boot loader.
6298 * Invoking guix system:: Instantiating a system configuration.
6299 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
6300 * Defining Services:: Adding new service definitions.
6303 @node Using the Configuration System
6304 @subsection Using the Configuration System
6306 The operating system is configured by providing an
6307 @code{operating-system} declaration in a file that can then be passed to
6308 the @command{guix system} command (@pxref{Invoking guix system}). A
6309 simple setup, with the default system services, the default Linux-Libre
6310 kernel, initial RAM disk, and boot loader looks like this:
6312 @findex operating-system
6314 @include os-config-bare-bones.texi
6317 This example should be self-describing. Some of the fields defined
6318 above, such as @code{host-name} and @code{bootloader}, are mandatory.
6319 Others, such as @code{packages} and @code{services}, can be omitted, in
6320 which case they get a default value.
6322 Below we discuss the effect of some of the most important fields
6323 (@pxref{operating-system Reference}, for details about all the available
6324 fields), and how to @dfn{instantiate} the operating system using
6325 @command{guix system}.
6327 @unnumberedsubsubsec Globally-Visible Packages
6329 @vindex %base-packages
6330 The @code{packages} field lists packages that will be globally visible
6331 on the system, for all user accounts---i.e., in every user's @code{PATH}
6332 environment variable---in addition to the per-user profiles
6333 (@pxref{Invoking guix package}). The @var{%base-packages} variable
6334 provides all the tools one would expect for basic user and administrator
6335 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
6336 the GNU Zile lightweight text editor, @command{find}, @command{grep},
6337 etc. The example above adds tcpdump to those, taken from the @code{(gnu
6338 packages admin)} module (@pxref{Package Modules}).
6340 @findex specification->package
6341 Referring to packages by variable name, like @var{tcpdump} above, has
6342 the advantage of being unambiguous; it also allows typos and such to be
6343 diagnosed right away as ``unbound variables''. The downside is that one
6344 needs to know which module defines which package, and to augment the
6345 @code{use-package-modules} line accordingly. To avoid that, one can use
6346 the @code{specification->package} procedure of the @code{(gnu packages)}
6347 module, which returns the best package for a given name or name and
6351 (use-modules (gnu packages))
6355 (packages (append (map specification->package
6356 '("tcpdump" "htop" "gnupg@@2.0"))
6360 @unnumberedsubsubsec System Services
6362 @vindex %base-services
6363 The @code{services} field lists @dfn{system services} to be made
6364 available when the system starts (@pxref{Services}).
6365 The @code{operating-system} declaration above specifies that, in
6366 addition to the basic services, we want the @command{lshd} secure shell
6367 daemon listening on port 2222 (@pxref{Networking Services,
6368 @code{lsh-service}}). Under the hood,
6369 @code{lsh-service} arranges so that @code{lshd} is started with the
6370 right command-line options, possibly with supporting configuration files
6371 generated as needed (@pxref{Defining Services}).
6373 @cindex customization, of services
6374 @findex modify-services
6375 Occasionally, instead of using the base services as is, you will want to
6376 customize them. To do this, use @code{modify-services} (@pxref{Service
6377 Reference, @code{modify-services}}) to modify the list.
6379 For example, suppose you want to modify @code{guix-daemon} and Mingetty
6380 (the console log-in) in the @var{%base-services} list (@pxref{Base
6381 Services, @code{%base-services}}). To do that, you can write the
6382 following in your operating system declaration:
6385 (define %my-services
6386 ;; My very own list of services.
6387 (modify-services %base-services
6388 (guix-service-type config =>
6391 (use-substitutes? #f)
6392 (extra-options '("--gc-keep-derivations"))))
6393 (mingetty-service-type config =>
6394 (mingetty-configuration
6396 (motd (plain-file "motd" "Howdy!"))))))
6400 (services %my-services))
6403 This changes the configuration---i.e., the service parameters---of the
6404 @code{guix-service-type} instance, and that of all the
6405 @code{mingetty-service-type} instances in the @var{%base-services} list.
6406 Observe how this is accomplished: first, we arrange for the original
6407 configuration to be bound to the identifier @code{config} in the
6408 @var{body}, and then we write the @var{body} so that it evaluates to the
6409 desired configuration. In particular, notice how we use @code{inherit}
6410 to create a new configuration which has the same values as the old
6411 configuration, but with a few modifications.
6413 The configuration for a typical ``desktop'' usage, with the X11 display
6414 server, GNOME and Xfce (users can choose which of these desktop
6415 environments to use at the log-in screen by pressing @kbd{F1}), network
6416 management, power management, and more, would look like this:
6419 @include os-config-desktop.texi
6422 A graphical environment with a choice of lightweight window managers
6423 instead of full-blown desktop environments would look like this:
6426 @include os-config-lightweight-desktop.texi
6429 @xref{Desktop Services}, for the exact list of services provided by
6430 @var{%desktop-services}. @xref{X.509 Certificates}, for background
6431 information about the @code{nss-certs} package that is used here.
6433 Again, @var{%desktop-services} is just a list of service objects. If
6434 you want to remove services from there, you can do so using the
6435 procedures for list filtering (@pxref{SRFI-1 Filtering and
6436 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
6437 following expression returns a list that contains all the services in
6438 @var{%desktop-services} minus the Avahi service:
6441 (remove (lambda (service)
6442 (eq? (service-kind service) avahi-service-type))
6446 @unnumberedsubsubsec Instantiating the System
6448 Assuming the @code{operating-system} declaration
6449 is stored in the @file{my-system-config.scm}
6450 file, the @command{guix system reconfigure my-system-config.scm} command
6451 instantiates that configuration, and makes it the default GRUB boot
6452 entry (@pxref{Invoking guix system}).
6454 The normal way to change the system configuration is by updating this
6455 file and re-running @command{guix system reconfigure}. One should never
6456 have to touch files in @command{/etc} or to run commands that modify the
6457 system state such as @command{useradd} or @command{grub-install}. In
6458 fact, you must avoid that since that would not only void your warranty
6459 but also prevent you from rolling back to previous versions of your
6460 system, should you ever need to.
6462 @cindex roll-back, of the operating system
6463 Speaking of roll-back, each time you run @command{guix system
6464 reconfigure}, a new @dfn{generation} of the system is created---without
6465 modifying or deleting previous generations. Old system generations get
6466 an entry in the GRUB boot menu, allowing you to boot them in case
6467 something went wrong with the latest generation. Reassuring, no? The
6468 @command{guix system list-generations} command lists the system
6469 generations available on disk.
6471 @unnumberedsubsubsec The Programming Interface
6473 At the Scheme level, the bulk of an @code{operating-system} declaration
6474 is instantiated with the following monadic procedure (@pxref{The Store
6477 @deffn {Monadic Procedure} operating-system-derivation os
6478 Return a derivation that builds @var{os}, an @code{operating-system}
6479 object (@pxref{Derivations}).
6481 The output of the derivation is a single directory that refers to all
6482 the packages, configuration files, and other supporting files needed to
6483 instantiate @var{os}.
6486 This procedure is provided by the @code{(gnu system)} module. Along
6487 with @code{(gnu services)} (@pxref{Services}), this module contains the
6488 guts of GuixSD. Make sure to visit it!
6491 @node operating-system Reference
6492 @subsection @code{operating-system} Reference
6494 This section summarizes all the options available in
6495 @code{operating-system} declarations (@pxref{Using the Configuration
6498 @deftp {Data Type} operating-system
6499 This is the data type representing an operating system configuration.
6500 By that, we mean all the global system configuration, not per-user
6501 configuration (@pxref{Using the Configuration System}).
6504 @item @code{kernel} (default: @var{linux-libre})
6505 The package object of the operating system kernel to use@footnote{Currently
6506 only the Linux-libre kernel is supported. In the future, it will be
6507 possible to use the GNU@tie{}Hurd.}.
6509 @item @code{kernel-arguments} (default: @code{'()})
6510 List of strings or gexps representing additional arguments to pass on
6511 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
6513 @item @code{bootloader}
6514 The system bootloader configuration object. @xref{GRUB Configuration}.
6516 @item @code{initrd} (default: @code{base-initrd})
6517 A two-argument monadic procedure that returns an initial RAM disk for
6518 the Linux kernel. @xref{Initial RAM Disk}.
6520 @item @code{firmware} (default: @var{%base-firmware})
6522 List of firmware packages loadable by the operating system kernel.
6524 The default includes firmware needed for Atheros-based WiFi devices
6525 (Linux-libre module @code{ath9k}). @xref{Hardware Considerations}, for
6526 more info on supported hardware.
6528 @item @code{host-name}
6531 @item @code{hosts-file}
6533 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
6534 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
6535 Reference Manual}). The default is a file with entries for
6536 @code{localhost} and @var{host-name}.
6538 @item @code{mapped-devices} (default: @code{'()})
6539 A list of mapped devices. @xref{Mapped Devices}.
6541 @item @code{file-systems}
6542 A list of file systems. @xref{File Systems}.
6544 @item @code{swap-devices} (default: @code{'()})
6545 @cindex swap devices
6546 A list of strings identifying devices to be used for ``swap space''
6547 (@pxref{Memory Concepts,,, libc, The GNU C Library Reference Manual}).
6548 For example, @code{'("/dev/sda3")}.
6550 @item @code{users} (default: @code{%base-user-accounts})
6551 @itemx @code{groups} (default: @var{%base-groups})
6552 List of user accounts and groups. @xref{User Accounts}.
6554 @item @code{skeletons} (default: @code{(default-skeletons)})
6555 A list target file name/file-like object tuples (@pxref{G-Expressions,
6556 file-like objects}). These are the skeleton files that will be added to
6557 the home directory of newly-created user accounts.
6559 For instance, a valid value may look like this:
6562 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
6563 (".guile" ,(plain-file "guile"
6564 "(use-modules (ice-9 readline))
6565 (activate-readline)")))
6568 @item @code{issue} (default: @var{%default-issue})
6569 A string denoting the contents of the @file{/etc/issue} file, which is
6570 displayed when users log in on a text console.
6572 @item @code{packages} (default: @var{%base-packages})
6573 The set of packages installed in the global profile, which is accessible
6574 at @file{/run/current-system/profile}.
6576 The default set includes core utilities and it is good practice to
6577 install non-core utilities in user profiles (@pxref{Invoking guix
6580 @item @code{timezone}
6581 A timezone identifying string---e.g., @code{"Europe/Paris"}.
6583 You can run the @command{tzselect} command to find out which timezone
6584 string corresponds to your region. Choosing an invalid timezone name
6585 causes @command{guix system} to fail.
6587 @item @code{locale} (default: @code{"en_US.utf8"})
6588 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
6589 Library Reference Manual}). @xref{Locales}, for more information.
6591 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
6592 The list of locale definitions to be compiled and that may be used at
6593 run time. @xref{Locales}.
6595 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
6596 The list of GNU@tie{}libc packages whose locale data and tools are used
6597 to build the locale definitions. @xref{Locales}, for compatibility
6598 considerations that justify this option.
6600 @item @code{name-service-switch} (default: @var{%default-nss})
6601 Configuration of the libc name service switch (NSS)---a
6602 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
6605 @item @code{services} (default: @var{%base-services})
6606 A list of service objects denoting system services. @xref{Services}.
6608 @item @code{pam-services} (default: @code{(base-pam-services)})
6610 @cindex pluggable authentication modules
6611 Linux @dfn{pluggable authentication module} (PAM) services.
6612 @c FIXME: Add xref to PAM services section.
6614 @item @code{setuid-programs} (default: @var{%setuid-programs})
6615 List of string-valued G-expressions denoting setuid programs.
6616 @xref{Setuid Programs}.
6618 @item @code{sudoers-file} (default: @var{%sudoers-specification})
6619 @cindex sudoers file
6620 The contents of the @file{/etc/sudoers} file as a file-like object
6621 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
6623 This file specifies which users can use the @command{sudo} command, what
6624 they are allowed to do, and what privileges they may gain. The default
6625 is that only @code{root} and members of the @code{wheel} group may use
6632 @subsection File Systems
6634 The list of file systems to be mounted is specified in the
6635 @code{file-systems} field of the operating system declaration
6636 (@pxref{Using the Configuration System}). Each file system is declared
6637 using the @code{file-system} form, like this:
6641 (mount-point "/home")
6642 (device "/dev/sda3")
6646 As usual, some of the fields are mandatory---those shown in the example
6647 above---while others can be omitted. These are described below.
6649 @deftp {Data Type} file-system
6650 Objects of this type represent file systems to be mounted. They
6651 contain the following members:
6655 This is a string specifying the type of the file system---e.g.,
6658 @item @code{mount-point}
6659 This designates the place where the file system is to be mounted.
6662 This names the ``source'' of the file system. By default it is the name
6663 of a node under @file{/dev}, but its meaning depends on the @code{title}
6664 field described below.
6666 @item @code{title} (default: @code{'device})
6667 This is a symbol that specifies how the @code{device} field is to be
6670 When it is the symbol @code{device}, then the @code{device} field is
6671 interpreted as a file name; when it is @code{label}, then @code{device}
6672 is interpreted as a partition label name; when it is @code{uuid},
6673 @code{device} is interpreted as a partition unique identifier (UUID).
6675 UUIDs may be converted from their string representation (as shown by the
6676 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
6677 @code{uuid} form expects 16-byte UUIDs as defined in
6678 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
6679 form of UUID used by the ext2 family of file systems and others, but it
6680 is different from ``UUIDs'' found in FAT file systems, for instance.},
6685 (mount-point "/home")
6688 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
6691 The @code{label} and @code{uuid} options offer a way to refer to disk
6692 partitions without having to hard-code their actual device
6693 name@footnote{Note that, while it is tempting to use
6694 @file{/dev/disk/by-uuid} and similar device names to achieve the same
6695 result, this is not recommended: These special device nodes are created
6696 by the udev daemon and may be unavailable at the time the device is
6699 However, when the source of a file system is a mapped device (@pxref{Mapped
6700 Devices}), its @code{device} field @emph{must} refer to the mapped
6701 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
6702 @code{title} must be set to @code{'device}. This is required so that
6703 the system knows that mounting the file system depends on having the
6704 corresponding device mapping established.
6706 @item @code{flags} (default: @code{'()})
6707 This is a list of symbols denoting mount flags. Recognized flags
6708 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
6709 access to special files), @code{no-suid} (ignore setuid and setgid
6710 bits), and @code{no-exec} (disallow program execution.)
6712 @item @code{options} (default: @code{#f})
6713 This is either @code{#f}, or a string denoting mount options.
6715 @item @code{mount?} (default: @code{#t})
6716 This value indicates whether to automatically mount the file system when
6717 the system is brought up. When set to @code{#f}, the file system gets
6718 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
6719 is not automatically mounted.
6721 @item @code{needed-for-boot?} (default: @code{#f})
6722 This Boolean value indicates whether the file system is needed when
6723 booting. If that is true, then the file system is mounted when the
6724 initial RAM disk (initrd) is loaded. This is always the case, for
6725 instance, for the root file system.
6727 @item @code{check?} (default: @code{#t})
6728 This Boolean indicates whether the file system needs to be checked for
6729 errors before being mounted.
6731 @item @code{create-mount-point?} (default: @code{#f})
6732 When true, the mount point is created if it does not exist yet.
6734 @item @code{dependencies} (default: @code{'()})
6735 This is a list of @code{<file-system>} objects representing file systems
6736 that must be mounted before (and unmounted after) this one.
6738 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
6739 a dependency of @file{/sys/fs/cgroup/cpu} and
6740 @file{/sys/fs/cgroup/memory}.
6745 The @code{(gnu system file-systems)} exports the following useful
6748 @defvr {Scheme Variable} %base-file-systems
6749 These are essential file systems that are required on normal systems,
6750 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
6751 below.) Operating system declarations should always contain at least
6755 @defvr {Scheme Variable} %pseudo-terminal-file-system
6756 This is the file system to be mounted as @file{/dev/pts}. It supports
6757 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
6758 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
6759 Manual}). Pseudo-terminals are used by terminal emulators such as
6763 @defvr {Scheme Variable} %shared-memory-file-system
6764 This file system is mounted as @file{/dev/shm} and is used to support
6765 memory sharing across processes (@pxref{Memory-mapped I/O,
6766 @code{shm_open},, libc, The GNU C Library Reference Manual}).
6769 @defvr {Scheme Variable} %immutable-store
6770 This file system performs a read-only ``bind mount'' of
6771 @file{/gnu/store}, making it read-only for all the users including
6772 @code{root}. This prevents against accidental modification by software
6773 running as @code{root} or by system administrators.
6775 The daemon itself is still able to write to the store: it remounts it
6776 read-write in its own ``name space.''
6779 @defvr {Scheme Variable} %binary-format-file-system
6780 The @code{binfmt_misc} file system, which allows handling of arbitrary
6781 executable file types to be delegated to user space. This requires the
6782 @code{binfmt.ko} kernel module to be loaded.
6785 @defvr {Scheme Variable} %fuse-control-file-system
6786 The @code{fusectl} file system, which allows unprivileged users to mount
6787 and unmount user-space FUSE file systems. This requires the
6788 @code{fuse.ko} kernel module to be loaded.
6791 @node Mapped Devices
6792 @subsection Mapped Devices
6794 @cindex device mapping
6795 @cindex mapped devices
6796 The Linux kernel has a notion of @dfn{device mapping}: a block device,
6797 such as a hard disk partition, can be @dfn{mapped} into another device,
6798 with additional processing over the data that flows through
6799 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
6800 concept of a ``mapped device'' and that of a file system: both boil down
6801 to @emph{translating} input/output operations made on a file to
6802 operations on its backing store. Thus, the Hurd implements mapped
6803 devices, like file systems, using the generic @dfn{translator} mechanism
6804 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
6805 typical example is encryption device mapping: all writes to the mapped
6806 device are encrypted, and all reads are deciphered, transparently.
6808 Mapped devices are declared using the @code{mapped-device} form:
6812 (source "/dev/sda3")
6814 (type luks-device-mapping))
6817 Or, better yet, like this:
6821 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
6823 (type luks-device-mapping))
6826 @cindex disk encryption
6828 This example specifies a mapping from @file{/dev/sda3} to
6829 @file{/dev/mapper/home} using LUKS---the
6830 @url{http://code.google.com/p/cryptsetup,Linux Unified Key Setup}, a
6831 standard mechanism for disk encryption. In the second example, the UUID
6832 (unique identifier) is the LUKS UUID returned for the device by a
6836 cryptsetup luksUUID /dev/sdx9
6839 The @file{/dev/mapper/home}
6840 device can then be used as the @code{device} of a @code{file-system}
6841 declaration (@pxref{File Systems}). The @code{mapped-device} form is
6844 @deftp {Data Type} mapped-device
6845 Objects of this type represent device mappings that will be made when
6846 the system boots up.
6850 This string specifies the name of the block device to be mapped, such as
6854 This string specifies the name of the mapping to be established. For
6855 example, specifying @code{"my-partition"} will lead to the creation of
6856 the @code{"/dev/mapper/my-partition"} device.
6859 This must be a @code{mapped-device-kind} object, which specifies how
6860 @var{source} is mapped to @var{target}.
6864 @defvr {Scheme Variable} luks-device-mapping
6865 This defines LUKS block device encryption using the @command{cryptsetup}
6866 command from the package with the same name. It relies on the
6867 @code{dm-crypt} Linux kernel module.
6871 @subsection User Accounts
6873 User accounts and groups are entirely managed through the
6874 @code{operating-system} declaration. They are specified with the
6875 @code{user-account} and @code{user-group} forms:
6881 (supplementary-groups '("wheel" ;allow use of sudo, etc.
6883 "video" ;video devices such as webcams
6884 "cdrom")) ;the good ol' CD-ROM
6885 (comment "Bob's sister")
6886 (home-directory "/home/alice"))
6889 When booting or upon completion of @command{guix system reconfigure},
6890 the system ensures that only the user accounts and groups specified in
6891 the @code{operating-system} declaration exist, and with the specified
6892 properties. Thus, account or group creations or modifications made by
6893 directly invoking commands such as @command{useradd} are lost upon
6894 reconfiguration or reboot. This ensures that the system remains exactly
6897 @deftp {Data Type} user-account
6898 Objects of this type represent user accounts. The following members may
6903 The name of the user account.
6906 This is the name (a string) or identifier (a number) of the user group
6907 this account belongs to.
6909 @item @code{supplementary-groups} (default: @code{'()})
6910 Optionally, this can be defined as a list of group names that this
6913 @item @code{uid} (default: @code{#f})
6914 This is the user ID for this account (a number), or @code{#f}. In the
6915 latter case, a number is automatically chosen by the system when the
6918 @item @code{comment} (default: @code{""})
6919 A comment about the account, such as the account owner's full name.
6921 @item @code{home-directory}
6922 This is the name of the home directory for the account.
6924 @item @code{shell} (default: Bash)
6925 This is a G-expression denoting the file name of a program to be used as
6926 the shell (@pxref{G-Expressions}).
6928 @item @code{system?} (default: @code{#f})
6929 This Boolean value indicates whether the account is a ``system''
6930 account. System accounts are sometimes treated specially; for instance,
6931 graphical login managers do not list them.
6933 @anchor{user-account-password}
6934 @item @code{password} (default: @code{#f})
6935 You would normally leave this field to @code{#f}, initialize user
6936 passwords as @code{root} with the @command{passwd} command, and then let
6937 users change it with @command{passwd}. Passwords set with
6938 @command{passwd} are of course preserved across reboot and
6941 If you @emph{do} want to have a preset password for an account, then
6942 this field must contain the encrypted password, as a string.
6943 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
6944 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
6945 Manual}, for information on Guile's @code{crypt} procedure.
6950 User group declarations are even simpler:
6953 (user-group (name "students"))
6956 @deftp {Data Type} user-group
6957 This type is for, well, user groups. There are just a few fields:
6961 The name of the group.
6963 @item @code{id} (default: @code{#f})
6964 The group identifier (a number). If @code{#f}, a new number is
6965 automatically allocated when the group is created.
6967 @item @code{system?} (default: @code{#f})
6968 This Boolean value indicates whether the group is a ``system'' group.
6969 System groups have low numerical IDs.
6971 @item @code{password} (default: @code{#f})
6972 What, user groups can have a password? Well, apparently yes. Unless
6973 @code{#f}, this field specifies the password of the group.
6978 For convenience, a variable lists all the basic user groups one may
6981 @defvr {Scheme Variable} %base-groups
6982 This is the list of basic user groups that users and/or packages expect
6983 to be present on the system. This includes groups such as ``root'',
6984 ``wheel'', and ``users'', as well as groups used to control access to
6985 specific devices such as ``audio'', ``disk'', and ``cdrom''.
6988 @defvr {Scheme Variable} %base-user-accounts
6989 This is the list of basic system accounts that programs may expect to
6990 find on a GNU/Linux system, such as the ``nobody'' account.
6992 Note that the ``root'' account is not included here. It is a
6993 special-case and is automatically added whether or not it is specified.
7000 A @dfn{locale} defines cultural conventions for a particular language
7001 and region of the world (@pxref{Locales,,, libc, The GNU C Library
7002 Reference Manual}). Each locale has a name that typically has the form
7003 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
7004 @code{fr_LU.utf8} designates the locale for the French language, with
7005 cultural conventions from Luxembourg, and using the UTF-8 encoding.
7007 @cindex locale definition
7008 Usually, you will want to specify the default locale for the machine
7009 using the @code{locale} field of the @code{operating-system} declaration
7010 (@pxref{operating-system Reference, @code{locale}}).
7012 The selected locale is automatically added to the @dfn{locale
7013 definitions} known to the system if needed, with its codeset inferred
7014 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
7015 @code{UTF-8} codeset. Additional locale definitions can be specified in
7016 the @code{locale-definitions} slot of @code{operating-system}---this is
7017 useful, for instance, if the codeset could not be inferred from the
7018 locale name. The default set of locale definitions includes some widely
7019 used locales, but not all the available locales, in order to save space.
7021 For instance, to add the North Frisian locale for Germany, the value of
7025 (cons (locale-definition
7026 (name "fy_DE.utf8") (source "fy_DE"))
7027 %default-locale-definitions)
7030 Likewise, to save space, one might want @code{locale-definitions} to
7031 list only the locales that are actually used, as in:
7034 (list (locale-definition
7035 (name "ja_JP.eucjp") (source "ja_JP")
7036 (charset "EUC-JP")))
7040 The compiled locale definitions are available at
7041 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
7042 version, which is the default location where the GNU@tie{}libc provided
7043 by Guix looks for locale data. This can be overridden using the
7044 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
7045 @code{LOCPATH} and locale packages}).
7047 The @code{locale-definition} form is provided by the @code{(gnu system
7048 locale)} module. Details are given below.
7050 @deftp {Data Type} locale-definition
7051 This is the data type of a locale definition.
7056 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
7057 Reference Manual}, for more information on locale names.
7060 The name of the source for that locale. This is typically the
7061 @code{@var{language}_@var{territory}} part of the locale name.
7063 @item @code{charset} (default: @code{"UTF-8"})
7064 The ``character set'' or ``code set'' for that locale,
7065 @uref{http://www.iana.org/assignments/character-sets, as defined by
7071 @defvr {Scheme Variable} %default-locale-definitions
7072 A list of commonly used UTF-8 locales, used as the default
7073 value of the @code{locale-definitions} field of @code{operating-system}
7077 @cindex normalized codeset in locale names
7078 These locale definitions use the @dfn{normalized codeset} for the part
7079 that follows the dot in the name (@pxref{Using gettextized software,
7080 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
7081 instance it has @code{uk_UA.utf8} but @emph{not}, say,
7085 @subsubsection Locale Data Compatibility Considerations
7087 @cindex incompatibility, of locale data
7088 @code{operating-system} declarations provide a @code{locale-libcs} field
7089 to specify the GNU@tie{}libc packages that are used to compile locale
7090 declarations (@pxref{operating-system Reference}). ``Why would I
7091 care?'', you may ask. Well, it turns out that the binary format of
7092 locale data is occasionally incompatible from one libc version to
7095 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
7096 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
7097 For instance, a program linked against libc version 2.21 is unable to
7098 read locale data produced with libc 2.22; worse, that program
7099 @emph{aborts} instead of simply ignoring the incompatible locale
7100 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
7101 the incompatible locale data, which is already an improvement.}.
7102 Similarly, a program linked against libc 2.22 can read most, but not
7103 all, the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
7104 data is incompatible); thus calls to @code{setlocale} may fail, but
7105 programs will not abort.
7107 The ``problem'' in GuixSD is that users have a lot of freedom: They can
7108 choose whether and when to upgrade software in their profiles, and might
7109 be using a libc version different from the one the system administrator
7110 used to build the system-wide locale data.
7112 Fortunately, unprivileged users can also install their own locale data
7113 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
7114 @code{GUIX_LOCPATH} and locale packages}).
7116 Still, it is best if the system-wide locale data at
7117 @file{/run/current-system/locale} is built for all the libc versions
7118 actually in use on the system, so that all the programs can access
7119 it---this is especially crucial on a multi-user system. To do that, the
7120 administrator can specify several libc packages in the
7121 @code{locale-libcs} field of @code{operating-system}:
7124 (use-package-modules base)
7128 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
7131 This example would lead to a system containing locale definitions for
7132 both libc 2.21 and the current version of libc in
7133 @file{/run/current-system/locale}.
7137 @subsection Services
7139 @cindex system services
7140 An important part of preparing an @code{operating-system} declaration is
7141 listing @dfn{system services} and their configuration (@pxref{Using the
7142 Configuration System}). System services are typically daemons launched
7143 when the system boots, or other actions needed at that time---e.g.,
7144 configuring network access.
7146 Services are managed by the GNU@tie{}Shepherd (@pxref{Introduction,,,
7147 shepherd, The GNU Shepherd Manual}). On a running system, the
7148 @command{herd} command allows you to list the available services, show
7149 their status, start and stop them, or do other specific operations
7150 (@pxref{Jump Start,,, shepherd, The GNU Shepherd Manual}). For example:
7156 The above command, run as @code{root}, lists the currently defined
7157 services. The @command{herd doc} command shows a synopsis of the given
7162 Run libc's name service cache daemon (nscd).
7165 The @command{start}, @command{stop}, and @command{restart} sub-commands
7166 have the effect you would expect. For instance, the commands below stop
7167 the nscd service and restart the Xorg display server:
7171 Service nscd has been stopped.
7172 # herd restart xorg-server
7173 Service xorg-server has been stopped.
7174 Service xorg-server has been started.
7177 The following sections document the available services, starting with
7178 the core services, that may be used in an @code{operating-system}
7182 * Base Services:: Essential system services.
7183 * Networking Services:: Network setup, SSH daemon, etc.
7184 * X Window:: Graphical display.
7185 * Desktop Services:: D-Bus and desktop services.
7186 * Database Services:: SQL databases.
7187 * Mail Services:: IMAP, POP3, SMTP, and all that.
7188 * Web Services:: Web servers.
7189 * Various Services:: Other services.
7193 @subsubsection Base Services
7195 The @code{(gnu services base)} module provides definitions for the basic
7196 services that one expects from the system. The services exported by
7197 this module are listed below.
7199 @defvr {Scheme Variable} %base-services
7200 This variable contains a list of basic services (@pxref{Service Types
7201 and Services}, for more information on service objects) one would
7202 expect from the system: a login service (mingetty) on each tty, syslogd,
7203 the libc name service cache daemon (nscd), the udev device manager, and
7206 This is the default value of the @code{services} field of
7207 @code{operating-system} declarations. Usually, when customizing a
7208 system, you will want to append services to @var{%base-services}, like
7212 (cons* (avahi-service) (lsh-service) %base-services)
7216 @deffn {Scheme Procedure} host-name-service @var{name}
7217 Return a service that sets the host name to @var{name}.
7220 @deffn {Scheme Procedure} mingetty-service @var{config}
7221 Return a service to run mingetty according to @var{config}, a
7222 @code{<mingetty-configuration>} object, which specifies the tty to run, among
7226 @deftp {Data Type} mingetty-configuration
7227 This is the data type representing the configuration of Mingetty, which
7228 implements console log-in.
7233 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
7236 A file-like object containing the ``message of the day''.
7238 @item @code{auto-login} (default: @code{#f})
7239 When true, this field must be a string denoting the user name under
7240 which the system automatically logs in. When it is @code{#f}, a
7241 user name and password must be entered to log in.
7243 @item @code{login-program} (default: @code{#f})
7244 This must be either @code{#f}, in which case the default log-in program
7245 is used (@command{login} from the Shadow tool suite), or a gexp denoting
7246 the name of the log-in program.
7248 @item @code{login-pause?} (default: @code{#f})
7249 When set to @code{#t} in conjunction with @var{auto-login}, the user
7250 will have to press a key before the log-in shell is launched.
7252 @item @code{mingetty} (default: @var{mingetty})
7253 The Mingetty package to use.
7258 @cindex name service cache daemon
7260 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
7261 [#:name-services '()]
7262 Return a service that runs the libc name service cache daemon (nscd) with the
7263 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
7264 Service Switch}, for an example.
7267 @defvr {Scheme Variable} %nscd-default-configuration
7268 This is the default @code{<nscd-configuration>} value (see below) used
7269 by @code{nscd-service}. It uses the caches defined by
7270 @var{%nscd-default-caches}; see below.
7273 @deftp {Data Type} nscd-configuration
7274 This is the data type representing the name service cache daemon (nscd)
7279 @item @code{name-services} (default: @code{'()})
7280 List of packages denoting @dfn{name services} that must be visible to
7281 the nscd---e.g., @code{(list @var{nss-mdns})}.
7283 @item @code{glibc} (default: @var{glibc})
7284 Package object denoting the GNU C Library providing the @command{nscd}
7287 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
7288 Name of the nscd log file. This is where debugging output goes when
7289 @code{debug-level} is strictly positive.
7291 @item @code{debug-level} (default: @code{0})
7292 Integer denoting the debugging levels. Higher numbers mean that more
7293 debugging output is logged.
7295 @item @code{caches} (default: @var{%nscd-default-caches})
7296 List of @code{<nscd-cache>} objects denoting things to be cached; see
7302 @deftp {Data Type} nscd-cache
7303 Data type representing a cache database of nscd and its parameters.
7307 @item @code{database}
7308 This is a symbol representing the name of the database to be cached.
7309 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
7310 @code{services}, which designate the corresponding NSS database
7311 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
7313 @item @code{positive-time-to-live}
7314 @itemx @code{negative-time-to-live} (default: @code{20})
7315 A number representing the number of seconds during which a positive or
7316 negative lookup result remains in cache.
7318 @item @code{check-files?} (default: @code{#t})
7319 Whether to check for updates of the files corresponding to
7322 For instance, when @var{database} is @code{hosts}, setting this flag
7323 instructs nscd to check for updates in @file{/etc/hosts} and to take
7326 @item @code{persistent?} (default: @code{#t})
7327 Whether the cache should be stored persistently on disk.
7329 @item @code{shared?} (default: @code{#t})
7330 Whether the cache should be shared among users.
7332 @item @code{max-database-size} (default: 32@tie{}MiB)
7333 Maximum size in bytes of the database cache.
7335 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
7336 @c settings, so leave them out.
7341 @defvr {Scheme Variable} %nscd-default-caches
7342 List of @code{<nscd-cache>} objects used by default by
7343 @code{nscd-configuration} (see above).
7345 It enables persistent and aggressive caching of service and host name
7346 lookups. The latter provides better host name lookup performance,
7347 resilience in the face of unreliable name servers, and also better
7348 privacy---often the result of host name lookups is in local cache, so
7349 external name servers do not even need to be queried.
7353 @deffn {Scheme Procedure} syslog-service @
7354 [#:config-file @var{%default-syslog.conf}]
7355 Return a service that runs @command{syslogd}. If the configuration file
7356 name @var{config-file} is not specified, use some reasonable default
7359 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
7360 information on the configuration file syntax.
7363 @anchor{guix-configuration-type}
7364 @deftp {Data Type} guix-configuration
7365 This data type represents the configuration of the Guix build daemon.
7366 @xref{Invoking guix-daemon}, for more information.
7369 @item @code{guix} (default: @var{guix})
7370 The Guix package to use.
7372 @item @code{build-group} (default: @code{"guixbuild"})
7373 Name of the group for build user accounts.
7375 @item @code{build-accounts} (default: @code{10})
7376 Number of build user accounts to create.
7378 @item @code{authorize-key?} (default: @code{#t})
7379 Whether to authorize the substitute key for @code{hydra.gnu.org}
7380 (@pxref{Substitutes}).
7382 @item @code{use-substitutes?} (default: @code{#t})
7383 Whether to use substitutes.
7385 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
7386 The list of URLs where to look for substitutes by default.
7388 @item @code{extra-options} (default: @code{'()})
7389 List of extra command-line options for @command{guix-daemon}.
7391 @item @code{lsof} (default: @var{lsof})
7392 @itemx @code{lsh} (default: @var{lsh})
7393 The lsof and lsh packages to use.
7398 @deffn {Scheme Procedure} guix-service @var{config}
7399 Return a service that runs the Guix build daemon according to
7403 @deffn {Scheme Procedure} udev-service [#:udev udev]
7404 Run @var{udev}, which populates the @file{/dev} directory dynamically.
7407 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
7408 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
7412 @defvr {Scheme Variable} %random-seed-file
7413 This is the name of the file where some random bytes are saved by
7414 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
7415 It defaults to @file{/var/lib/random-seed}.
7418 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
7419 @cindex keyboard layout
7420 Return a service to load console keymaps from @var{files} using
7421 @command{loadkeys} command. Most likely, you want to load some default
7422 keymap, which can be done like this:
7425 (console-keymap-service "dvorak")
7428 Or, for example, for a Swedish keyboard, you may need to combine
7429 the following keymaps:
7431 (console-keymap-service "se-lat6" "se-fi-lat6")
7434 Also you can specify a full file name (or file names) of your keymap(s).
7435 See @code{man loadkeys} for details.
7439 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
7441 Run @var{gpm}, the general-purpose mouse daemon, with the given
7442 command-line @var{options}. GPM allows users to use the mouse in the console,
7443 notably to select, copy, and paste text. The default value of @var{options}
7444 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
7446 This service is not part of @var{%base-services}.
7449 @anchor{guix-publish-service}
7450 @deffn {Scheme Procedure} guix-publish-service [#:guix @var{guix}] @
7451 [#:port 80] [#:host "localhost"]
7452 Return a service that runs @command{guix publish} listening on @var{host}
7453 and @var{port} (@pxref{Invoking guix publish}).
7455 This assumes that @file{/etc/guix} already contains a signing key pair as
7456 created by @command{guix archive --generate-key} (@pxref{Invoking guix
7457 archive}). If that is not the case, the service will fail to start.
7461 @node Networking Services
7462 @subsubsection Networking Services
7464 The @code{(gnu services networking)} module provides services to configure
7465 the network interface.
7467 @cindex DHCP, networking service
7468 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
7469 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
7470 Protocol (DHCP) client, on all the non-loopback network interfaces.
7473 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
7474 [#:gateway #f] [#:name-services @code{'()}]
7475 Return a service that starts @var{interface} with address @var{ip}. If
7476 @var{gateway} is true, it must be a string specifying the default network
7481 @cindex network management
7482 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
7483 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
7484 management daemon that aims to simplify wired and wireless networking.
7486 This service adds the @var{wicd} package to the global profile, providing
7487 several commands to interact with the daemon and configure networking:
7488 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
7489 and @command{wicd-curses} user interfaces.
7492 @cindex NetworkManager
7493 @deffn {Scheme Procedure} network-manager-service @
7494 [#:network-manager @var{network-manager}]
7495 Return a service that runs NetworkManager, a network connection manager
7496 attempting to keep network connectivity active when available.
7500 @deffn {Scheme Procedure} connman-service @
7501 [#:connman @var{connman}]
7502 Return a service that runs @url{https://01.org/connman,Connman}, a network
7505 This service adds the @var{connman} package to the global profile, providing
7506 several the @command{connmanctl} command to interact with the daemon and
7507 configure networking."
7510 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
7511 [#:name-service @var{%ntp-servers}]
7512 Return a service that runs the daemon from @var{ntp}, the
7513 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
7514 keep the system clock synchronized with that of @var{servers}.
7517 @defvr {Scheme Variable} %ntp-servers
7518 List of host names used as the default NTP servers.
7521 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
7522 Return a service to run the @uref{https://torproject.org, Tor} anonymous
7525 The daemon runs as the @code{tor} unprivileged user. It is passed
7526 @var{config-file}, a file-like object, with an additional @code{User tor} line
7527 and lines for hidden services added via @code{tor-hidden-service}. Run
7528 @command{man tor} for information about the configuration file.
7531 @cindex hidden service
7532 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
7533 Define a new Tor @dfn{hidden service} called @var{name} and implementing
7534 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
7537 '((22 "127.0.0.1:22")
7538 (80 "127.0.0.1:8080"))
7541 In this example, port 22 of the hidden service is mapped to local port 22, and
7542 port 80 is mapped to local port 8080.
7544 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
7545 the @file{hostname} file contains the @code{.onion} host name for the hidden
7548 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
7549 project's documentation} for more information.
7552 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
7553 [#:interface "127.0.0.1"] [#:port 6667] @
7554 [#:extra-settings ""]
7555 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
7556 acts as a gateway between IRC and chat networks.
7558 The daemon will listen to the interface corresponding to the IP address
7559 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
7560 local clients can connect, whereas @code{0.0.0.0} means that connections can
7561 come from any networking interface.
7563 In addition, @var{extra-settings} specifies a string to append to the
7567 Furthermore, @code{(gnu services ssh)} provides the following service.
7569 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
7570 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
7571 [#:allow-empty-passwords? #f] [#:root-login? #f] @
7572 [#:syslog-output? #t] [#:x11-forwarding? #t] @
7573 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
7574 [#:public-key-authentication? #t] [#:initialize? #t]
7575 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
7576 @var{host-key} must designate a file containing the host key, and readable
7579 When @var{daemonic?} is true, @command{lshd} will detach from the
7580 controlling terminal and log its output to syslogd, unless one sets
7581 @var{syslog-output?} to false. Obviously, it also makes lsh-service
7582 depend on existence of syslogd service. When @var{pid-file?} is true,
7583 @command{lshd} writes its PID to the file called @var{pid-file}.
7585 When @var{initialize?} is true, automatically create the seed and host key
7586 upon service activation if they do not exist yet. This may take long and
7587 require interaction.
7589 When @var{initialize?} is false, it is up to the user to initialize the
7590 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
7591 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
7592 basics,,, lsh, LSH Manual}).
7594 When @var{interfaces} is empty, lshd listens for connections on all the
7595 network interfaces; otherwise, @var{interfaces} must be a list of host names
7598 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
7599 passwords, and @var{root-login?} specifies whether to accept log-ins as
7602 The other options should be self-descriptive.
7605 @defvr {Scheme Variable} %facebook-host-aliases
7606 This variable contains a string for use in @file{/etc/hosts}
7607 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
7608 line contains a entry that maps a known server name of the Facebook
7609 on-line service---e.g., @code{www.facebook.com}---to the local
7610 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
7612 This variable is typically used in the @code{hosts-file} field of an
7613 @code{operating-system} declaration (@pxref{operating-system Reference,
7614 @file{/etc/hosts}}):
7617 (use-modules (gnu) (guix))
7620 (host-name "mymachine")
7623 ;; Create a /etc/hosts file with aliases for "localhost"
7624 ;; and "mymachine", as well as for Facebook servers.
7626 (string-append (local-host-aliases host-name)
7627 %facebook-host-aliases))))
7630 This mechanism can prevent programs running locally, such as Web
7631 browsers, from accessing Facebook.
7634 The @code{(gnu services avahi)} provides the following definition.
7636 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
7637 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
7638 [#:ipv6? #t] [#:wide-area? #f] @
7639 [#:domains-to-browse '()]
7640 Return a service that runs @command{avahi-daemon}, a system-wide
7641 mDNS/DNS-SD responder that allows for service discovery and
7642 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
7643 extends the name service cache daemon (nscd) so that it can resolve
7644 @code{.local} host names using
7645 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
7646 add the @var{avahi} package to the system profile so that commands such as
7647 @command{avahi-browse} are directly usable.
7649 If @var{host-name} is different from @code{#f}, use that as the host name to
7650 publish for this machine; otherwise, use the machine's actual host name.
7652 When @var{publish?} is true, publishing of host names and services is allowed;
7653 in particular, avahi-daemon will publish the machine's host name and IP
7654 address via mDNS on the local network.
7656 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
7658 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
7664 @subsubsection X Window
7666 Support for the X Window graphical display system---specifically
7667 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
7668 there is no @code{xorg-service} procedure. Instead, the X server is
7669 started by the @dfn{login manager}, currently SLiM.
7671 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
7672 [#:auto-login? #f] [#:default-user ""] [#:startx] @
7673 [#:theme @var{%default-slim-theme}] @
7674 [#:theme-name @var{%default-slim-theme-name}]
7675 Return a service that spawns the SLiM graphical login manager, which in
7676 turn starts the X display server with @var{startx}, a command as returned by
7677 @code{xorg-start-command}.
7681 SLiM automatically looks for session types described by the @file{.desktop}
7682 files in @file{/run/current-system/profile/share/xsessions} and allows users
7683 to choose a session from the log-in screen using @kbd{F1}. Packages such as
7684 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
7685 adding them to the system-wide set of packages automatically makes them
7686 available at the log-in screen.
7688 In addition, @file{~/.xsession} files are honored. When available,
7689 @file{~/.xsession} must be an executable that starts a window manager
7690 and/or other X clients.
7692 When @var{allow-empty-passwords?} is true, allow logins with an empty
7693 password. When @var{auto-login?} is true, log in automatically as
7696 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
7697 @var{theme} must be a gexp denoting the name of a directory containing the
7698 theme to use. In that case, @var{theme-name} specifies the name of the
7702 @defvr {Scheme Variable} %default-theme
7703 @defvrx {Scheme Variable} %default-theme-name
7704 The G-Expression denoting the default SLiM theme and its name.
7707 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
7708 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
7709 Return a derivation that builds a @var{guile} script to start the X server
7710 from @var{xorg-server}. @var{configuration-file} is the server configuration
7711 file or a derivation that builds it; when omitted, the result of
7712 @code{xorg-configuration-file} is used.
7714 Usually the X server is started by a login manager.
7717 @deffn {Scheme Procedure} xorg-configuration-file @
7718 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
7719 Return a configuration file for the Xorg server containing search paths for
7720 all the common drivers.
7722 @var{drivers} must be either the empty list, in which case Xorg chooses a
7723 graphics driver automatically, or a list of driver names that will be tried in
7724 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
7726 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
7727 appropriate screen resolution; otherwise, it must be a list of
7728 resolutions---e.g., @code{((1024 768) (640 480))}.
7730 Last, @var{extra-config} is a list of strings or objects appended to the
7731 @code{text-file*} argument list. It is used to pass extra text to be added
7732 verbatim to the configuration file.
7735 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
7736 Add @var{package}, a package for a screen-locker or screen-saver whose
7737 command is @var{program}, to the set of setuid programs and add a PAM entry
7738 for it. For example:
7741 (screen-locker-service xlockmore "xlock")
7744 makes the good ol' XlockMore usable.
7748 @node Desktop Services
7749 @subsubsection Desktop Services
7751 The @code{(gnu services desktop)} module provides services that are
7752 usually useful in the context of a ``desktop'' setup---that is, on a
7753 machine running a graphical display server, possibly with graphical user
7754 interfaces, etc. It also defines services that provide specific desktop
7755 environments like GNOME and XFCE.
7757 To simplify things, the module defines a variable containing the set of
7758 services that users typically expect on a machine with a graphical
7759 environment and networking:
7761 @defvr {Scheme Variable} %desktop-services
7762 This is a list of services that builds upon @var{%base-services} and
7763 adds or adjusts services for a typical ``desktop'' setup.
7765 In particular, it adds a graphical login manager (@pxref{X Window,
7766 @code{slim-service}}), screen lockers,
7767 a network management tool (@pxref{Networking
7768 Services, @code{wicd-service}}), energy and color management services,
7769 the @code{elogind} login and seat manager, the Polkit privilege service,
7770 the GeoClue location service, an NTP client (@pxref{Networking
7771 Services}), the Avahi daemon, and has the name service switch service
7772 configured to be able to use @code{nss-mdns} (@pxref{Name Service
7776 The @var{%desktop-services} variable can be used as the @code{services}
7777 field of an @code{operating-system} declaration (@pxref{operating-system
7778 Reference, @code{services}}).
7780 Additionally, the @code{gnome-desktop-service} and
7781 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
7782 system. To ``add GNOME'' means that system-level services like the
7783 backlight adjustment helpers and the power management utilities are
7784 added to the system, extending @code{polkit} and @code{dbus}
7785 appropriately, allowing GNOME to operate with elevated privileges on a
7786 limited number of special-purpose system interfaces. Additionally,
7787 adding a service made by @code{gnome-desktop-service} adds the GNOME
7788 metapackage to the system profile. Likewise, adding the XFCE service
7789 not only adds the @code{xfce} metapackage to the system profile, but it
7790 also gives the Thunar file manager the ability to open a ``root-mode''
7791 file management window, if the user authenticates using the
7792 administrator's password via the standard polkit graphical interface.
7794 @deffn {Scheme Procedure} gnome-desktop-service
7795 Return a service that adds the @code{gnome} package to the system
7796 profile, and extends polkit with the actions from
7797 @code{gnome-settings-daemon}.
7800 @deffn {Scheme Procedure} xfce-desktop-service
7801 Return a service that adds the @code{xfce} package to the system profile,
7802 and extends polkit with the abilit for @code{thunar} to manipulate the
7803 file system as root from within a user session, after the user has
7804 authenticated with the administrator's password.
7807 Because the GNOME and XFCE desktop services pull in so many packages,
7808 the default @code{%desktop-services} variable doesn't include either of
7809 them by default. To add GNOME or XFCE, just @code{cons} them onto
7810 @code{%desktop-services} in the @code{services} field of your
7811 @code{operating-system}:
7815 (use-service-modules desktop)
7818 ;; cons* adds items to the list given as its last argument.
7819 (services (cons* (gnome-desktop-service)
7820 (xfce-desktop-service)
7825 These desktop environments will then be available as options in the
7826 graphical login window.
7828 The actual service definitions included in @code{%desktop-services} and
7829 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
7830 are described below.
7832 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
7833 Return a service that runs the ``system bus'', using @var{dbus}, with
7834 support for @var{services}.
7836 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
7837 facility. Its system bus is used to allow system services to communicate
7838 and to be notified of system-wide events.
7840 @var{services} must be a list of packages that provide an
7841 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
7842 and policy files. For example, to allow avahi-daemon to use the system bus,
7843 @var{services} must be equal to @code{(list avahi)}.
7846 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
7847 Return a service that runs the @code{elogind} login and
7848 seat management daemon. @uref{https://github.com/andywingo/elogind,
7849 Elogind} exposes a D-Bus interface that can be used to know which users
7850 are logged in, know what kind of sessions they have open, suspend the
7851 system, inhibit system suspend, reboot the system, and other tasks.
7853 Elogind handles most system-level power events for a computer, for
7854 example suspending the system when a lid is closed, or shutting it down
7855 when the power button is pressed.
7857 The @var{config} keyword argument specifies the configuration for
7858 elogind, and should be the result of an @code{(elogind-configuration
7859 (@var{parameter} @var{value})...)} invocation. Available parameters and
7860 their default values are:
7863 @item kill-user-processes?
7865 @item kill-only-users
7867 @item kill-exclude-users
7869 @item inhibit-delay-max-seconds
7871 @item handle-power-key
7873 @item handle-suspend-key
7875 @item handle-hibernate-key
7877 @item handle-lid-switch
7879 @item handle-lid-switch-docked
7881 @item power-key-ignore-inhibited?
7883 @item suspend-key-ignore-inhibited?
7885 @item hibernate-key-ignore-inhibited?
7887 @item lid-switch-ignore-inhibited?
7889 @item holdoff-timeout-seconds
7893 @item idle-action-seconds
7895 @item runtime-directory-size-percent
7897 @item runtime-directory-size
7902 @code{("mem" "standby" "freeze")}
7905 @item hibernate-state
7907 @item hibernate-mode
7908 @code{("platform" "shutdown")}
7909 @item hybrid-sleep-state
7911 @item hybrid-sleep-mode
7912 @code{("suspend" "platform" "shutdown")}
7916 @deffn {Scheme Procedure} polkit-service @
7917 [#:polkit @var{polkit}]
7918 Return a service that runs the
7919 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
7920 management service}, which allows system administrators to grant access to
7921 privileged operations in a structured way. By querying the Polkit service, a
7922 privileged system component can know when it should grant additional
7923 capabilities to ordinary users. For example, an ordinary user can be granted
7924 the capability to suspend the system if the user is logged in locally.
7927 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
7928 [#:watts-up-pro? #f] @
7929 [#:poll-batteries? #t] @
7930 [#:ignore-lid? #f] @
7931 [#:use-percentage-for-policy? #f] @
7932 [#:percentage-low 10] @
7933 [#:percentage-critical 3] @
7934 [#:percentage-action 2] @
7936 [#:time-critical 300] @
7937 [#:time-action 120] @
7938 [#:critical-power-action 'hybrid-sleep]
7939 Return a service that runs @uref{http://upower.freedesktop.org/,
7940 @command{upowerd}}, a system-wide monitor for power consumption and battery
7941 levels, with the given configuration settings. It implements the
7942 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
7946 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
7947 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
7948 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
7949 notifications and ways to mount/unmount disks. Programs that talk to UDisks
7950 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
7953 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
7954 Return a service that runs @command{colord}, a system service with a D-Bus
7955 interface to manage the color profiles of input and output devices such as
7956 screens and scanners. It is notably used by the GNOME Color Manager graphical
7957 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
7958 site} for more information.
7961 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
7962 Return a configuration allowing an application to access GeoClue
7963 location data. @var{name} is the Desktop ID of the application, without
7964 the @code{.desktop} part. If @var{allowed?} is true, the application
7965 will have access to location information by default. The boolean
7966 @var{system?} value indicates whether an application is a system component
7967 or not. Finally @var{users} is a list of UIDs of all users for which
7968 this application is allowed location info access. An empty users list
7969 means that all users are allowed.
7972 @defvr {Scheme Variable} %standard-geoclue-applications
7973 The standard list of well-known GeoClue application configurations,
7974 granting authority to the GNOME date-and-time utility to ask for the
7975 current location in order to set the time zone, and allowing the
7976 IceCat and Epiphany web browsers to request location information.
7977 IceCat and Epiphany both query the user before allowing a web page to
7978 know the user's location.
7981 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
7983 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
7985 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
7986 [#:submission-nick "geoclue"] @
7987 [#:applications %standard-geoclue-applications]
7988 Return a service that runs the GeoClue location service. This service
7989 provides a D-Bus interface to allow applications to request access to a
7990 user's physical location, and optionally to add information to online
7991 location databases. See
7992 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
7993 web site} for more information.
7996 @node Database Services
7997 @subsubsection Database Services
7999 The @code{(gnu services databases)} module provides the following service.
8001 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
8002 [#:config-file] [#:data-directory ``/var/lib/postgresql/data'']
8003 Return a service that runs @var{postgresql}, the PostgreSQL database
8006 The PostgreSQL daemon loads its runtime configuration from
8007 @var{config-file} and stores the database cluster in
8008 @var{data-directory}.
8012 @subsubsection Mail Services
8014 The @code{(gnu services mail)} module provides Guix service definitions
8015 for mail services. Currently the only implemented service is Dovecot,
8016 an IMAP, POP3, and LMTP server.
8018 Guix does not yet have a mail transfer agent (MTA), although for some
8019 lightweight purposes the @code{esmtp} relay-only MTA may suffice. Help
8020 is needed to properly integrate a full MTA, such as Postfix. Patches
8023 To add an IMAP/POP3 server to a GuixSD system, add a
8024 @code{dovecot-service} to the operating system definition:
8026 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
8027 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
8030 By default, Dovecot does not need much configuration; the default
8031 configuration object created by @code{(dovecot-configuration)} will
8032 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
8033 certificate will be generated for TLS-protected connections, though
8034 Dovecot will also listen on cleartext ports by default. There are a
8035 number of options, though, which mail administrators might need to change,
8036 and as is the case with other services, Guix allows the system
8037 administrator to specify these parameters via a uniform Scheme interface.
8039 For example, to specify that mail is located at @code{maildir~/.mail},
8040 one would instantiate the Dovecot service like this:
8043 (dovecot-service #:config
8044 (dovecot-configuration
8045 (mail-location "maildir:~/.mail")))
8048 The available configuration parameters follow. Each parameter
8049 definition is preceded by its type; for example, @samp{string-list foo}
8050 indicates that the @code{foo} parameter should be specified as a list of
8051 strings. There is also a way to specify the configuration as a string,
8052 if you have an old @code{dovecot.conf} file that you want to port over
8053 from some other system; see the end for more details.
8055 @c The following documentation was initially generated by
8056 @c (generate-documentation) in (gnu services mail). Manually maintained
8057 @c documentation is better, so we shouldn't hesitate to edit below as
8058 @c needed. However if the change you want to make to this documentation
8059 @c can be done in an automated way, it's probably easier to change
8060 @c (generate-documentation) than to make it below and have to deal with
8061 @c the churn as dovecot updates.
8063 Available @code{dovecot-configuration} fields are:
8065 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
8066 The dovecot package.
8069 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
8070 A list of IPs or hosts where to listen for connections. @samp{*}
8071 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
8072 interfaces. If you want to specify non-default ports or anything more
8073 complex, customize the address and port fields of the
8074 @samp{inet-listener} of the specific services you are interested in.
8077 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
8078 List of protocols we want to serve. Available protocols include
8079 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
8081 Available @code{protocol-configuration} fields are:
8083 @deftypevr {@code{protocol-configuration} parameter} string name
8084 The name of the protocol.
8087 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
8088 UNIX socket path to the master authentication server to find users.
8089 This is used by imap (for shared users) and lda.
8090 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
8093 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
8094 Space separated list of plugins to load.
8097 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
8098 Maximum number of IMAP connections allowed for a user from each IP
8099 address. NOTE: The username is compared case-sensitively.
8100 Defaults to @samp{10}.
8105 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
8106 List of services to enable. Available services include @samp{imap},
8107 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
8110 Available @code{service-configuration} fields are:
8112 @deftypevr {@code{service-configuration} parameter} string kind
8113 The service kind. Valid values include @code{director},
8114 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
8115 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
8116 @code{tcpwrap}, @code{quota-warning}, or anything else.
8119 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
8120 Listeners for the service. A listener is either a
8121 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
8122 an @code{inet-listener-configuration}.
8123 Defaults to @samp{()}.
8125 Available @code{unix-listener-configuration} fields are:
8127 @deftypevr {@code{unix-listener-configuration} parameter} file-name path
8128 The file name on which to listen.
8131 @deftypevr {@code{unix-listener-configuration} parameter} string mode
8132 The access mode for the socket.
8133 Defaults to @samp{"0600"}.
8136 @deftypevr {@code{unix-listener-configuration} parameter} string user
8137 The user to own the socket.
8138 Defaults to @samp{""}.
8141 @deftypevr {@code{unix-listener-configuration} parameter} string group
8142 The group to own the socket.
8143 Defaults to @samp{""}.
8147 Available @code{fifo-listener-configuration} fields are:
8149 @deftypevr {@code{fifo-listener-configuration} parameter} file-name path
8150 The file name on which to listen.
8153 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
8154 The access mode for the socket.
8155 Defaults to @samp{"0600"}.
8158 @deftypevr {@code{fifo-listener-configuration} parameter} string user
8159 The user to own the socket.
8160 Defaults to @samp{""}.
8163 @deftypevr {@code{fifo-listener-configuration} parameter} string group
8164 The group to own the socket.
8165 Defaults to @samp{""}.
8169 Available @code{inet-listener-configuration} fields are:
8171 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
8172 The protocol to listen for.
8175 @deftypevr {@code{inet-listener-configuration} parameter} string address
8176 The address on which to listen, or empty for all addresses.
8177 Defaults to @samp{""}.
8180 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
8181 The port on which to listen.
8184 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
8185 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
8187 Defaults to @samp{#t}.
8192 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
8193 Number of connections to handle before starting a new process.
8194 Typically the only useful values are 0 (unlimited) or 1. 1 is more
8195 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
8196 Defaults to @samp{1}.
8199 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
8200 Number of processes to always keep waiting for more connections.
8201 Defaults to @samp{0}.
8204 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
8205 If you set @samp{service-count 0}, you probably need to grow
8207 Defaults to @samp{256000000}.
8212 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
8213 Dict configuration, as created by the @code{dict-configuration}
8216 Available @code{dict-configuration} fields are:
8218 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
8219 A list of key-value pairs that this dict should hold.
8220 Defaults to @samp{()}.
8225 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
8226 A list of passdb configurations, each one created by the
8227 @code{passdb-configuration} constructor.
8229 Available @code{passdb-configuration} fields are:
8231 @deftypevr {@code{passdb-configuration} parameter} string driver
8232 The driver that the passdb should use. Valid values include
8233 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
8235 Defaults to @samp{"pam"}.
8238 @deftypevr {@code{passdb-configuration} parameter} free-form-args args
8239 A list of key-value args to the passdb driver.
8240 Defaults to @samp{()}.
8245 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
8246 List of userdb configurations, each one created by the
8247 @code{userdb-configuration} constructor.
8249 Available @code{userdb-configuration} fields are:
8251 @deftypevr {@code{userdb-configuration} parameter} string driver
8252 The driver that the userdb should use. Valid values include
8253 @samp{passwd} and @samp{static}.
8254 Defaults to @samp{"passwd"}.
8257 @deftypevr {@code{userdb-configuration} parameter} free-form-args args
8258 A list of key-value args to the userdb driver.
8259 Defaults to @samp{()}.
8262 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
8263 Override fields from passwd.
8264 Defaults to @samp{()}.
8269 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
8270 Plug-in configuration, created by the @code{plugin-configuration}
8274 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
8275 List of namespaces. Each item in the list is created by the
8276 @code{namespace-configuration} constructor.
8278 Available @code{namespace-configuration} fields are:
8280 @deftypevr {@code{namespace-configuration} parameter} string name
8281 Name for this namespace.
8284 @deftypevr {@code{namespace-configuration} parameter} string type
8285 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
8286 Defaults to @samp{"private"}.
8289 @deftypevr {@code{namespace-configuration} parameter} string separator
8290 Hierarchy separator to use. You should use the same separator for
8291 all namespaces or some clients get confused. @samp{/} is usually a good
8292 one. The default however depends on the underlying mail storage
8294 Defaults to @samp{""}.
8297 @deftypevr {@code{namespace-configuration} parameter} string prefix
8298 Prefix required to access this namespace. This needs to be
8299 different for all namespaces. For example @samp{Public/}.
8300 Defaults to @samp{""}.
8303 @deftypevr {@code{namespace-configuration} parameter} string location
8304 Physical location of the mailbox. This is in the same format as
8305 mail_location, which is also the default for it.
8306 Defaults to @samp{""}.
8309 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
8310 There can be only one INBOX, and this setting defines which
8312 Defaults to @samp{#f}.
8315 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
8316 If namespace is hidden, it's not advertised to clients via NAMESPACE
8317 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
8318 useful when converting from another server with different namespaces
8319 which you want to deprecate but still keep working. For example you can
8320 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
8322 Defaults to @samp{#f}.
8325 @deftypevr {@code{namespace-configuration} parameter} boolean list?
8326 Show the mailboxes under this namespace with the LIST command. This
8327 makes the namespace visible for clients that do not support the NAMESPACE
8328 extension. The special @code{children} value lists child mailboxes, but
8329 hides the namespace prefix.
8330 Defaults to @samp{#t}.
8333 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
8334 Namespace handles its own subscriptions. If set to @code{#f}, the
8335 parent namespace handles them. The empty prefix should always have this
8337 Defaults to @samp{#t}.
8340 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
8341 List of predefined mailboxes in this namespace.
8342 Defaults to @samp{()}.
8344 Available @code{mailbox-configuration} fields are:
8346 @deftypevr {@code{mailbox-configuration} parameter} string name
8347 Name for this mailbox.
8350 @deftypevr {@code{mailbox-configuration} parameter} string auto
8351 @samp{create} will automatically create this mailbox.
8352 @samp{subscribe} will both create and subscribe to the mailbox.
8353 Defaults to @samp{"no"}.
8356 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
8357 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
8358 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
8359 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
8360 Defaults to @samp{()}.
8367 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
8368 Base directory where to store runtime data.
8369 Defaults to @samp{"/var/run/dovecot/"}.
8372 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
8373 Greeting message for clients.
8374 Defaults to @samp{"Dovecot ready."}.
8377 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
8378 List of trusted network ranges. Connections from these IPs are
8379 allowed to override their IP addresses and ports (for logging and for
8380 authentication checks). @samp{disable-plaintext-auth} is also ignored
8381 for these networks. Typically you would specify your IMAP proxy servers
8383 Defaults to @samp{()}.
8386 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
8387 List of login access check sockets (e.g. tcpwrap).
8388 Defaults to @samp{()}.
8391 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
8392 Show more verbose process titles (in ps). Currently shows user name
8393 and IP address. Useful for seeing who is actually using the IMAP
8394 processes (e.g. shared mailboxes or if the same uid is used for multiple
8396 Defaults to @samp{#f}.
8399 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
8400 Should all processes be killed when Dovecot master process shuts down.
8401 Setting this to @code{#f} means that Dovecot can be upgraded without
8402 forcing existing client connections to close (although that could also
8403 be a problem if the upgrade is e.g. due to a security fix).
8404 Defaults to @samp{#t}.
8407 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
8408 If non-zero, run mail commands via this many connections to doveadm
8409 server, instead of running them directly in the same process.
8410 Defaults to @samp{0}.
8413 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
8414 UNIX socket or host:port used for connecting to doveadm server.
8415 Defaults to @samp{"doveadm-server"}.
8418 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
8419 List of environment variables that are preserved on Dovecot startup
8420 and passed down to all of its child processes. You can also give
8421 key=value pairs to always set specific settings.
8424 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
8425 Disable LOGIN command and all other plaintext authentications unless
8426 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
8427 matches the local IP (i.e. you're connecting from the same computer),
8428 the connection is considered secure and plaintext authentication is
8429 allowed. See also ssl=required setting.
8430 Defaults to @samp{#t}.
8433 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
8434 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
8435 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
8436 for caching to be used.
8437 Defaults to @samp{0}.
8440 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
8441 Time to live for cached data. After TTL expires the cached record
8442 is no longer used, *except* if the main database lookup returns internal
8443 failure. We also try to handle password changes automatically: If
8444 user's previous authentication was successful, but this one wasn't, the
8445 cache isn't used. For now this works only with plaintext
8447 Defaults to @samp{"1 hour"}.
8450 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
8451 TTL for negative hits (user not found, password mismatch).
8452 0 disables caching them completely.
8453 Defaults to @samp{"1 hour"}.
8456 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
8457 List of realms for SASL authentication mechanisms that need them.
8458 You can leave it empty if you don't want to support multiple realms.
8459 Many clients simply use the first one listed here, so keep the default
8461 Defaults to @samp{()}.
8464 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
8465 Default realm/domain to use if none was specified. This is used for
8466 both SASL realms and appending @@domain to username in plaintext
8468 Defaults to @samp{""}.
8471 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
8472 List of allowed characters in username. If the user-given username
8473 contains a character not listed in here, the login automatically fails.
8474 This is just an extra check to make sure user can't exploit any
8475 potential quote escaping vulnerabilities with SQL/LDAP databases. If
8476 you want to allow all characters, set this value to empty.
8477 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
8480 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
8481 Username character translations before it's looked up from
8482 databases. The value contains series of from -> to characters. For
8483 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
8484 translated to @samp{@@}.
8485 Defaults to @samp{""}.
8488 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
8489 Username formatting before it's looked up from databases. You can
8490 use the standard variables here, e.g. %Lu would lowercase the username,
8491 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
8492 change the @samp{@@} into @samp{-AT-}. This translation is done after
8493 @samp{auth-username-translation} changes.
8494 Defaults to @samp{"%Lu"}.
8497 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
8498 If you want to allow master users to log in by specifying the master
8499 username within the normal username string (i.e. not using SASL
8500 mechanism's support for it), you can specify the separator character
8501 here. The format is then <username><separator><master username>.
8502 UW-IMAP uses @samp{*} as the separator, so that could be a good
8504 Defaults to @samp{""}.
8507 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
8508 Username to use for users logging in with ANONYMOUS SASL
8510 Defaults to @samp{"anonymous"}.
8513 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
8514 Maximum number of dovecot-auth worker processes. They're used to
8515 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
8516 They're automatically created and destroyed as needed.
8517 Defaults to @samp{30}.
8520 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
8521 Host name to use in GSSAPI principal names. The default is to use
8522 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
8523 allow all keytab entries.
8524 Defaults to @samp{""}.
8527 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
8528 Kerberos keytab to use for the GSSAPI mechanism. Will use the
8529 system default (usually /etc/krb5.keytab) if not specified. You may
8530 need to change the auth service to run as root to be able to read this
8532 Defaults to @samp{""}.
8535 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
8536 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
8537 and @samp{ntlm-auth} helper.
8538 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
8539 Defaults to @samp{#f}.
8542 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
8543 Path for Samba's @samp{ntlm-auth} helper binary.
8544 Defaults to @samp{"/usr/bin/ntlm_auth"}.
8547 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
8548 Time to delay before replying to failed authentications.
8549 Defaults to @samp{"2 secs"}.
8552 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
8553 Require a valid SSL client certificate or the authentication
8555 Defaults to @samp{#f}.
8558 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
8559 Take the username from client's SSL certificate, using
8560 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
8562 Defaults to @samp{#f}.
8565 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
8566 List of wanted authentication mechanisms. Supported mechanisms are:
8567 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
8568 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
8569 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
8570 @samp{disable-plaintext-auth} setting.
8573 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
8574 List of IPs or hostnames to all director servers, including ourself.
8575 Ports can be specified as ip:port. The default port is the same as what
8576 director service's @samp{inet-listener} is using.
8577 Defaults to @samp{()}.
8580 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
8581 List of IPs or hostnames to all backend mail servers. Ranges are
8582 allowed too, like 10.0.0.10-10.0.0.30.
8583 Defaults to @samp{()}.
8586 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
8587 How long to redirect users to a specific server after it no longer
8588 has any connections.
8589 Defaults to @samp{"15 min"}.
8592 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
8593 TCP/IP port that accepts doveadm connections (instead of director
8594 connections) If you enable this, you'll also need to add
8595 @samp{inet-listener} for the port.
8596 Defaults to @samp{0}.
8599 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
8600 How the username is translated before being hashed. Useful values
8601 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
8602 are shared within domain.
8603 Defaults to @samp{"%Lu"}.
8606 @deftypevr {@code{dovecot-configuration} parameter} string log-path
8607 Log file to use for error messages. @samp{syslog} logs to syslog,
8608 @samp{/dev/stderr} logs to stderr.
8609 Defaults to @samp{"syslog"}.
8612 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
8613 Log file to use for informational messages. Defaults to
8615 Defaults to @samp{""}.
8618 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
8619 Log file to use for debug messages. Defaults to
8620 @samp{info-log-path}.
8621 Defaults to @samp{""}.
8624 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
8625 Syslog facility to use if you're logging to syslog. Usually if you
8626 don't want to use @samp{mail}, you'll use local0..local7. Also other
8627 standard facilities are supported.
8628 Defaults to @samp{"mail"}.
8631 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
8632 Log unsuccessful authentication attempts and the reasons why they
8634 Defaults to @samp{#f}.
8637 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
8638 In case of password mismatches, log the attempted password. Valid
8639 values are no, plain and sha1. sha1 can be useful for detecting brute
8640 force password attempts vs. user simply trying the same password over
8641 and over again. You can also truncate the value to n chars by appending
8643 Defaults to @samp{#f}.
8646 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
8647 Even more verbose logging for debugging purposes. Shows for example
8649 Defaults to @samp{#f}.
8652 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
8653 In case of password mismatches, log the passwords and used scheme so
8654 the problem can be debugged. Enabling this also enables
8656 Defaults to @samp{#f}.
8659 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
8660 Enable mail process debugging. This can help you figure out why
8661 Dovecot isn't finding your mails.
8662 Defaults to @samp{#f}.
8665 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
8666 Show protocol level SSL errors.
8667 Defaults to @samp{#f}.
8670 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
8671 Prefix for each line written to log file. % codes are in
8673 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
8676 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
8677 List of elements we want to log. The elements which have a
8678 non-empty variable value are joined together to form a comma-separated
8682 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
8683 Login log format. %s contains @samp{login-log-format-elements}
8684 string, %$ contains the data we want to log.
8685 Defaults to @samp{"%$: %s"}.
8688 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
8689 Log prefix for mail processes. See doc/wiki/Variables.txt for list
8690 of possible variables you can use.
8691 Defaults to @samp{"\"%s(%u): \""}.
8694 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
8695 Format to use for logging mail deliveries. You can use variables:
8698 Delivery status message (e.g. @samp{saved to INBOX})
8710 Defaults to @samp{"msgid=%m: %$"}.
8713 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
8714 Location for users' mailboxes. The default is empty, which means
8715 that Dovecot tries to find the mailboxes automatically. This won't work
8716 if the user doesn't yet have any mail, so you should explicitly tell
8717 Dovecot the full location.
8719 If you're using mbox, giving a path to the INBOX
8720 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
8721 where the other mailboxes are kept. This is called the "root mail
8722 directory", and it must be the first path given in the
8723 @samp{mail-location} setting.
8725 There are a few special variables you can use, eg.:
8731 user part in user@@domain, same as %u if there's no domain
8733 domain part in user@@domain, empty if there's no domain
8738 See doc/wiki/Variables.txt for full list. Some examples:
8740 @item maildir:~/Maildir
8741 @item mbox:~/mail:INBOX=/var/mail/%u
8742 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
8744 Defaults to @samp{""}.
8747 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
8748 System user and group used to access mails. If you use multiple,
8749 userdb can override these by returning uid or gid fields. You can use
8750 either numbers or names. <doc/wiki/UserIds.txt>.
8751 Defaults to @samp{""}.
8754 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
8756 Defaults to @samp{""}.
8759 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
8760 Group to enable temporarily for privileged operations. Currently
8761 this is used only with INBOX when either its initial creation or
8762 dotlocking fails. Typically this is set to "mail" to give access to
8764 Defaults to @samp{""}.
8767 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
8768 Grant access to these supplementary groups for mail processes.
8769 Typically these are used to set up access to shared mailboxes. Note
8770 that it may be dangerous to set these if users can create
8771 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
8772 could allow a user to delete others' mailboxes, or ln -s
8773 /secret/shared/box ~/mail/mybox would allow reading it).
8774 Defaults to @samp{""}.
8777 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
8778 Allow full filesystem access to clients. There's no access checks
8779 other than what the operating system does for the active UID/GID. It
8780 works with both maildir and mboxes, allowing you to prefix mailboxes
8781 names with e.g. /path/ or ~user/.
8782 Defaults to @samp{#f}.
8785 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
8786 Don't use mmap() at all. This is required if you store indexes to
8787 shared filesystems (NFS or clustered filesystem).
8788 Defaults to @samp{#f}.
8791 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
8792 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
8793 supports @samp{O_EXCL} since version 3, so this should be safe to use
8794 nowadays by default.
8795 Defaults to @samp{#t}.
8798 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
8799 When to use fsync() or fdatasync() calls:
8802 Whenever necessary to avoid losing important data
8804 Useful with e.g. NFS when write()s are delayed
8806 Never use it (best performance, but crashes can lose data).
8808 Defaults to @samp{"optimized"}.
8811 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
8812 Mail storage exists in NFS. Set this to yes to make Dovecot flush
8813 NFS caches whenever needed. If you're using only a single mail server
8815 Defaults to @samp{#f}.
8818 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
8819 Mail index files also exist in NFS. Setting this to yes requires
8820 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
8821 Defaults to @samp{#f}.
8824 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
8825 Locking method for index files. Alternatives are fcntl, flock and
8826 dotlock. Dotlocking uses some tricks which may create more disk I/O
8827 than other locking methods. NFS users: flock doesn't work, remember to
8828 change @samp{mmap-disable}.
8829 Defaults to @samp{"fcntl"}.
8832 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
8833 Directory in which LDA/LMTP temporarily stores incoming mails >128
8835 Defaults to @samp{"/tmp"}.
8838 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
8839 Valid UID range for users. This is mostly to make sure that users can't
8840 log in as daemons or other system users. Note that denying root logins is
8841 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
8843 Defaults to @samp{500}.
8846 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
8848 Defaults to @samp{0}.
8851 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
8852 Valid GID range for users. Users having non-valid GID as primary group ID
8853 aren't allowed to log in. If user belongs to supplementary groups with
8854 non-valid GIDs, those groups are not set.
8855 Defaults to @samp{1}.
8858 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
8860 Defaults to @samp{0}.
8863 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
8864 Maximum allowed length for mail keyword name. It's only forced when
8865 trying to create new keywords.
8866 Defaults to @samp{50}.
8869 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
8870 List of directories under which chrooting is allowed for mail
8871 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
8872 too). This setting doesn't affect @samp{login-chroot}
8873 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
8874 "/./" in home dirs are ignored. WARNING: Never add directories here
8875 which local users can modify, that may lead to root exploit. Usually
8876 this should be done only if you don't allow shell access for users.
8877 <doc/wiki/Chrooting.txt>.
8878 Defaults to @samp{()}.
8881 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
8882 Default chroot directory for mail processes. This can be overridden
8883 for specific users in user database by giving /./ in user's home
8884 directory (e.g. /home/./user chroots into /home). Note that usually
8885 there is no real need to do chrooting, Dovecot doesn't allow users to
8886 access files outside their mail directory anyway. If your home
8887 directories are prefixed with the chroot directory, append "/." to
8888 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
8889 Defaults to @samp{""}.
8892 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
8893 UNIX socket path to master authentication server to find users.
8894 This is used by imap (for shared users) and lda.
8895 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
8898 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
8899 Directory where to look up mail plugins.
8900 Defaults to @samp{"/usr/lib/dovecot"}.
8903 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
8904 List of plugins to load for all services. Plugins specific to IMAP,
8905 LDA, etc. are added to this list in their own .conf files.
8906 Defaults to @samp{()}.
8909 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
8910 The minimum number of mails in a mailbox before updates are done to
8911 cache file. This allows optimizing Dovecot's behavior to do less disk
8912 writes at the cost of more disk reads.
8913 Defaults to @samp{0}.
8916 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
8917 When IDLE command is running, mailbox is checked once in a while to
8918 see if there are any new mails or other changes. This setting defines
8919 the minimum time to wait between those checks. Dovecot can also use
8920 dnotify, inotify and kqueue to find out immediately when changes
8922 Defaults to @samp{"30 secs"}.
8925 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
8926 Save mails with CR+LF instead of plain LF. This makes sending those
8927 mails take less CPU, especially with sendfile() syscall with Linux and
8928 FreeBSD. But it also creates a bit more disk I/O which may just make it
8929 slower. Also note that if other software reads the mboxes/maildirs,
8930 they may handle the extra CRs wrong and cause problems.
8931 Defaults to @samp{#f}.
8934 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
8935 By default LIST command returns all entries in maildir beginning
8936 with a dot. Enabling this option makes Dovecot return only entries
8937 which are directories. This is done by stat()ing each entry, so it
8938 causes more disk I/O.
8939 (For systems setting struct @samp{dirent->d_type} this check is free
8940 and it's done always regardless of this setting).
8941 Defaults to @samp{#f}.
8944 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
8945 When copying a message, do it with hard links whenever possible.
8946 This makes the performance much better, and it's unlikely to have any
8948 Defaults to @samp{#t}.
8951 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
8952 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
8953 directory only when its mtime changes unexpectedly or when we can't find
8955 Defaults to @samp{#f}.
8958 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
8959 Which locking methods to use for locking mbox. There are four
8964 Create <mailbox>.lock file. This is the oldest and most NFS-safe
8965 solution. If you want to use /var/mail/ like directory, the users will
8966 need write access to that directory.
8968 Same as dotlock, but if it fails because of permissions or because there
8969 isn't enough disk space, just skip it.
8971 Use this if possible. Works with NFS too if lockd is used.
8973 May not exist in all systems. Doesn't work with NFS.
8975 May not exist in all systems. Doesn't work with NFS.
8978 You can use multiple locking methods; if you do the order they're declared
8979 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
8980 locking methods as well. Some operating systems don't allow using some of
8981 them simultaneously.
8984 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
8988 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
8989 Maximum time to wait for lock (all of them) before aborting.
8990 Defaults to @samp{"5 mins"}.
8993 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
8994 If dotlock exists but the mailbox isn't modified in any way,
8995 override the lock file after this much time.
8996 Defaults to @samp{"2 mins"}.
8999 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
9000 When mbox changes unexpectedly we have to fully read it to find out
9001 what changed. If the mbox is large this can take a long time. Since
9002 the change is usually just a newly appended mail, it'd be faster to
9003 simply read the new mails. If this setting is enabled, Dovecot does
9004 this but still safely fallbacks to re-reading the whole mbox file
9005 whenever something in mbox isn't how it's expected to be. The only real
9006 downside to this setting is that if some other MUA changes message
9007 flags, Dovecot doesn't notice it immediately. Note that a full sync is
9008 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
9009 Defaults to @samp{#t}.
9012 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
9013 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
9014 EXAMINE, EXPUNGE or CHECK commands. If this is set,
9015 @samp{mbox-dirty-syncs} is ignored.
9016 Defaults to @samp{#f}.
9019 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
9020 Delay writing mbox headers until doing a full write sync (EXPUNGE
9021 and CHECK commands and when closing the mailbox). This is especially
9022 useful for POP3 where clients often delete all mails. The downside is
9023 that our changes aren't immediately visible to other MUAs.
9024 Defaults to @samp{#t}.
9027 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
9028 If mbox size is smaller than this (e.g. 100k), don't write index
9029 files. If an index file already exists it's still read, just not
9031 Defaults to @samp{0}.
9034 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
9035 Maximum dbox file size until it's rotated.
9036 Defaults to @samp{2000000}.
9039 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
9040 Maximum dbox file age until it's rotated. Typically in days. Day
9041 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
9043 Defaults to @samp{"1d"}.
9046 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
9047 When creating new mdbox files, immediately preallocate their size to
9048 @samp{mdbox-rotate-size}. This setting currently works only in Linux
9049 with some filesystems (ext4, xfs).
9050 Defaults to @samp{#f}.
9053 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
9054 sdbox and mdbox support saving mail attachments to external files,
9055 which also allows single instance storage for them. Other backends
9056 don't support this for now.
9058 WARNING: This feature hasn't been tested much yet. Use at your own risk.
9060 Directory root where to store mail attachments. Disabled, if empty.
9061 Defaults to @samp{""}.
9064 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
9065 Attachments smaller than this aren't saved externally. It's also
9066 possible to write a plugin to disable saving specific attachments
9068 Defaults to @samp{128000}.
9071 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
9072 Filesystem backend to use for saving attachments:
9075 No SiS done by Dovecot (but this might help FS's own deduplication)
9077 SiS with immediate byte-by-byte comparison during saving
9078 @item sis-queue posix
9079 SiS with delayed comparison and deduplication.
9081 Defaults to @samp{"sis posix"}.
9084 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
9085 Hash format to use in attachment filenames. You can add any text and
9086 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
9087 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
9088 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
9089 Defaults to @samp{"%@{sha1@}"}.
9092 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
9094 Defaults to @samp{100}.
9097 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
9099 Defaults to @samp{1000}.
9102 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
9103 Default VSZ (virtual memory size) limit for service processes.
9104 This is mainly intended to catch and kill processes that leak memory
9105 before they eat up everything.
9106 Defaults to @samp{256000000}.
9109 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
9110 Login user is internally used by login processes. This is the most
9111 untrusted user in Dovecot system. It shouldn't have access to anything
9113 Defaults to @samp{"dovenull"}.
9116 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
9117 Internal user is used by unprivileged processes. It should be
9118 separate from login user, so that login processes can't disturb other
9120 Defaults to @samp{"dovecot"}.
9123 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
9124 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
9125 Defaults to @samp{"required"}.
9128 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
9129 PEM encoded X.509 SSL/TLS certificate (public key).
9130 Defaults to @samp{"</etc/dovecot/default.pem"}.
9133 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
9134 PEM encoded SSL/TLS private key. The key is opened before
9135 dropping root privileges, so keep the key file unreadable by anyone but
9137 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
9140 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
9141 If key file is password protected, give the password here.
9142 Alternatively give it when starting dovecot with -p parameter. Since
9143 this file is often world-readable, you may want to place this setting
9144 instead to a different.
9145 Defaults to @samp{""}.
9148 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
9149 PEM encoded trusted certificate authority. Set this only if you
9150 intend to use @samp{ssl-verify-client-cert? #t}. The file should
9151 contain the CA certificate(s) followed by the matching
9152 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
9153 Defaults to @samp{""}.
9156 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
9157 Require that CRL check succeeds for client certificates.
9158 Defaults to @samp{#t}.
9161 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
9162 Request client to send a certificate. If you also want to require
9163 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
9164 Defaults to @samp{#f}.
9167 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
9168 Which field from certificate to use for username. commonName and
9169 x500UniqueIdentifier are the usual choices. You'll also need to set
9170 @samp{auth-ssl-username-from-cert? #t}.
9171 Defaults to @samp{"commonName"}.
9174 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
9175 How often to regenerate the SSL parameters file. Generation is
9176 quite CPU intensive operation. The value is in hours, 0 disables
9177 regeneration entirely.
9178 Defaults to @samp{168}.
9181 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
9182 SSL protocols to use.
9183 Defaults to @samp{"!SSLv2"}.
9186 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
9188 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
9191 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
9192 SSL crypto device to use, for valid values run "openssl engine".
9193 Defaults to @samp{""}.
9196 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
9197 Address to use when sending rejection mails.
9198 Default is postmaster@@<your domain>. %d expands to recipient domain.
9199 Defaults to @samp{""}.
9202 @deftypevr {@code{dovecot-configuration} parameter} string hostname
9203 Hostname to use in various parts of sent mails (e.g. in Message-Id)
9204 and in LMTP replies. Default is the system's real hostname@@domain.
9205 Defaults to @samp{""}.
9208 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
9209 If user is over quota, return with temporary failure instead of
9211 Defaults to @samp{#f}.
9214 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
9215 Binary to use for sending mails.
9216 Defaults to @samp{"/usr/sbin/sendmail"}.
9219 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
9220 If non-empty, send mails via this SMTP host[:port] instead of
9222 Defaults to @samp{""}.
9225 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
9226 Subject: header to use for rejection mails. You can use the same
9227 variables as for @samp{rejection-reason} below.
9228 Defaults to @samp{"Rejected: %s"}.
9231 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
9232 Human readable error message for rejection mails. You can use
9245 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
9248 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
9249 Delimiter character between local-part and detail in email
9251 Defaults to @samp{"+"}.
9254 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
9255 Header where the original recipient address (SMTP's RCPT TO:
9256 address) is taken from if not available elsewhere. With dovecot-lda -a
9257 parameter overrides this. A commonly used header for this is
9259 Defaults to @samp{""}.
9262 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
9263 Should saving a mail to a nonexistent mailbox automatically create
9265 Defaults to @samp{#f}.
9268 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
9269 Should automatically created mailboxes be also automatically
9271 Defaults to @samp{#f}.
9274 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
9275 Maximum IMAP command line length. Some clients generate very long
9276 command lines with huge mailboxes, so you may need to raise this if you
9277 get "Too long argument" or "IMAP command line too large" errors
9279 Defaults to @samp{64000}.
9282 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
9283 IMAP logout format string:
9286 total number of bytes read from client
9288 total number of bytes sent to client.
9290 Defaults to @samp{"in=%i out=%o"}.
9293 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
9294 Override the IMAP CAPABILITY response. If the value begins with '+',
9295 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
9296 Defaults to @samp{""}.
9299 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
9300 How long to wait between "OK Still here" notifications when client
9302 Defaults to @samp{"2 mins"}.
9305 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
9306 ID field names and values to send to clients. Using * as the value
9307 makes Dovecot use the default value. The following fields have default
9308 values currently: name, version, os, os-version, support-url,
9310 Defaults to @samp{""}.
9313 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
9314 ID fields sent by client to log. * means everything.
9315 Defaults to @samp{""}.
9318 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
9319 Workarounds for various client bugs:
9323 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
9324 CHECK commands. Some clients ignore them otherwise, for example OSX
9325 Mail (<v2.1). Outlook Express breaks more badly though, without this it
9326 may show user "Message no longer in server" errors. Note that OE6
9327 still breaks even with this workaround if synchronization is set to
9330 @item tb-extra-mailbox-sep
9331 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
9332 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
9333 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
9336 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
9337 This makes Thunderbird realize they aren't selectable and show them
9338 greyed out, instead of only later giving "not selectable" popup error.
9340 Defaults to @samp{()}.
9343 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
9344 Host allowed in URLAUTH URLs sent by client. "*" allows all.
9345 Defaults to @samp{""}.
9349 Whew! Lots of configuration options. The nice thing about it though is
9350 that GuixSD has a complete interface to Dovecot's configuration
9351 language. This allows not only a nice way to declare configurations,
9352 but also offers reflective capabilities as well: users can write code to
9353 inspect and transform configurations from within Scheme.
9355 However, it could be that you just want to get a @code{dovecot.conf} up
9356 and running. In that case, you can pass an
9357 @code{opaque-dovecot-configuration} as the @code{#:config} paramter to
9358 @code{dovecot-service}. As its name indicates, an opaque configuration
9359 does not have easy reflective capabilities.
9361 Available @code{opaque-dovecot-configuration} fields are:
9363 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
9364 The dovecot package.
9367 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
9368 The contents of the @code{dovecot.conf}, as a string.
9371 For example, if your @code{dovecot.conf} is just the empty string, you
9372 could instantiate a dovecot service like this:
9375 (dovecot-service #:config
9376 (opaque-dovecot-configuration
9381 @subsubsection Web Services
9383 The @code{(gnu services web)} module provides the following service:
9385 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
9386 [#:log-directory ``/var/log/nginx''] @
9387 [#:run-directory ``/var/run/nginx''] @
9390 Return a service that runs @var{nginx}, the nginx web server.
9392 The nginx daemon loads its runtime configuration from @var{config-file}.
9393 Log files are written to @var{log-directory} and temporary runtime data
9394 files are written to @var{run-directory}. For proper operation, these
9395 arguments should match what is in @var{config-file} to ensure that the
9396 directories are created when the service is activated.
9400 @node Various Services
9401 @subsubsection Various Services
9403 The @code{(gnu services lirc)} module provides the following service.
9405 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
9406 [#:device #f] [#:driver #f] [#:config-file #f] @
9407 [#:extra-options '()]
9408 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
9409 decodes infrared signals from remote controls.
9411 Optionally, @var{device}, @var{driver} and @var{config-file}
9412 (configuration file name) may be specified. See @command{lircd} manual
9415 Finally, @var{extra-options} is a list of additional command-line options
9416 passed to @command{lircd}.
9419 @subsubsection Dictionary Services
9420 The @code{(gnu services dict)} module provides the following service:
9422 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
9423 Return a service that runs the @command{dicod} daemon, an implementation
9424 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
9426 The optional @var{config} argument specifies the configuration for
9427 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
9428 default it serves the GNU Collaborative International Dictonary of English.
9430 You can add @command{open localhost} to your @file{~/.dico} file to make
9431 @code{localhost} the default server for @command{dico} client
9432 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
9435 @deftp {Data Type} dicod-configuration
9436 Data type representing the configuration of dicod.
9439 @item @code{dico} (default: @var{dico})
9440 Package object of the GNU Dico dictionary server.
9442 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
9443 List of @code{<dicod-database>} objects denoting dictionaries to be served.
9447 @deftp {Data Type} dicod-database
9448 Data type representing a dictionary database.
9452 Name of the database, will be used in DICT commands.
9455 Name of the dicod module used by this database
9456 (@pxref{Modules,,, dico, GNU Dico Manual}).
9458 @item @code{options}
9459 List of strings or gexps representing the arguments for the module handler
9460 (@pxref{Handlers,,, dico, GNU Dico Manual}).
9464 @defvr {Scheme Variable} %dicod-database:gcide
9465 A @code{<dicod-database>} object serving the GNU Collaborative International
9466 Dictonary of English using the @code{gcide} package.
9469 @node Setuid Programs
9470 @subsection Setuid Programs
9472 @cindex setuid programs
9473 Some programs need to run with ``root'' privileges, even when they are
9474 launched by unprivileged users. A notorious example is the
9475 @command{passwd} program, which users can run to change their
9476 password, and which needs to access the @file{/etc/passwd} and
9477 @file{/etc/shadow} files---something normally restricted to root, for
9478 obvious security reasons. To address that, these executables are
9479 @dfn{setuid-root}, meaning that they always run with root privileges
9480 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
9481 for more info about the setuid mechanism.)
9483 The store itself @emph{cannot} contain setuid programs: that would be a
9484 security issue since any user on the system can write derivations that
9485 populate the store (@pxref{The Store}). Thus, a different mechanism is
9486 used: instead of changing the setuid bit directly on files that are in
9487 the store, we let the system administrator @emph{declare} which programs
9488 should be setuid root.
9490 The @code{setuid-programs} field of an @code{operating-system}
9491 declaration contains a list of G-expressions denoting the names of
9492 programs to be setuid-root (@pxref{Using the Configuration System}).
9493 For instance, the @command{passwd} program, which is part of the Shadow
9494 package, can be designated by this G-expression (@pxref{G-Expressions}):
9497 #~(string-append #$shadow "/bin/passwd")
9500 A default set of setuid programs is defined by the
9501 @code{%setuid-programs} variable of the @code{(gnu system)} module.
9503 @defvr {Scheme Variable} %setuid-programs
9504 A list of G-expressions denoting common programs that are setuid-root.
9506 The list includes commands such as @command{passwd}, @command{ping},
9507 @command{su}, and @command{sudo}.
9510 Under the hood, the actual setuid programs are created in the
9511 @file{/run/setuid-programs} directory at system activation time. The
9512 files in this directory refer to the ``real'' binaries, which are in the
9515 @node X.509 Certificates
9516 @subsection X.509 Certificates
9518 @cindex HTTPS, certificates
9519 @cindex X.509 certificates
9521 Web servers available over HTTPS (that is, HTTP over the transport-layer
9522 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
9523 that the client can then use to @emph{authenticate} the server. To do
9524 that, clients verify that the server's certificate is signed by a
9525 so-called @dfn{certificate authority} (CA). But to verify the CA's
9526 signature, clients must have first acquired the CA's certificate.
9528 Web browsers such as GNU@tie{}IceCat include their own set of CA
9529 certificates, such that they are able to verify CA signatures
9532 However, most other programs that can talk HTTPS---@command{wget},
9533 @command{git}, @command{w3m}, etc.---need to be told where CA
9534 certificates can be found.
9536 @cindex @code{nss-certs}
9537 In GuixSD, this is done by adding a package that provides certificates
9538 to the @code{packages} field of the @code{operating-system} declaration
9539 (@pxref{operating-system Reference}). GuixSD includes one such package,
9540 @code{nss-certs}, which is a set of CA certificates provided as part of
9541 Mozilla's Network Security Services.
9543 Note that it is @emph{not} part of @var{%base-packages}, so you need to
9544 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
9545 most applications and libraries look for certificates by default, points
9546 to the certificates installed globally.
9548 Unprivileged users, including users of Guix on a foreign distro,
9549 can also install their own certificate package in
9550 their profile. A number of environment variables need to be defined so
9551 that applications and libraries know where to find them. Namely, the
9552 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
9553 variables. Some applications add their own environment variables; for
9554 instance, the Git version control system honors the certificate bundle
9555 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
9556 would typically run something like:
9559 $ guix package -i nss-certs
9560 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
9561 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
9562 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
9565 @node Name Service Switch
9566 @subsection Name Service Switch
9568 @cindex name service switch
9570 The @code{(gnu system nss)} module provides bindings to the
9571 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
9572 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
9573 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
9574 extended with new ``name'' lookup methods for system databases, which
9575 includes host names, service names, user accounts, and more (@pxref{Name
9576 Service Switch, System Databases and Name Service Switch,, libc, The GNU
9577 C Library Reference Manual}).
9579 The NSS configuration specifies, for each system database, which lookup
9580 method is to be used, and how the various methods are chained
9581 together---for instance, under which circumstances NSS should try the
9582 next method in the list. The NSS configuration is given in the
9583 @code{name-service-switch} field of @code{operating-system} declarations
9584 (@pxref{operating-system Reference, @code{name-service-switch}}).
9587 @cindex .local, host name lookup
9588 As an example, the declaration below configures the NSS to use the
9589 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
9590 back-end}, which supports host name lookups over multicast DNS (mDNS)
9591 for host names ending in @code{.local}:
9594 (name-service-switch
9595 (hosts (list %files ;first, check /etc/hosts
9597 ;; If the above did not succeed, try
9598 ;; with 'mdns_minimal'.
9600 (name "mdns_minimal")
9602 ;; 'mdns_minimal' is authoritative for
9603 ;; '.local'. When it returns "not found",
9604 ;; no need to try the next methods.
9605 (reaction (lookup-specification
9606 (not-found => return))))
9608 ;; Then fall back to DNS.
9612 ;; Finally, try with the "full" 'mdns'.
9617 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
9618 contains this configuration, so you will not have to type it if all you
9619 want is to have @code{.local} host lookup working.
9621 Note that, in this case, in addition to setting the
9622 @code{name-service-switch} of the @code{operating-system} declaration,
9623 you also need to use @code{avahi-service} (@pxref{Networking Services,
9624 @code{avahi-service}}), or @var{%desktop-services}, which includes it
9625 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
9626 to the name service cache daemon (@pxref{Base Services,
9627 @code{nscd-service}}).
9629 For convenience, the following variables provide typical NSS
9632 @defvr {Scheme Variable} %default-nss
9633 This is the default name service switch configuration, a
9634 @code{name-service-switch} object.
9637 @defvr {Scheme Variable} %mdns-host-lookup-nss
9638 This is the name service switch configuration with support for host name
9639 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
9642 The reference for name service switch configuration is given below. It
9643 is a direct mapping of the configuration file format of the C library , so
9644 please refer to the C library manual for more information (@pxref{NSS
9645 Configuration File,,, libc, The GNU C Library Reference Manual}).
9646 Compared to the configuration file format of libc NSS, it has the advantage
9647 not only of adding this warm parenthetic feel that we like, but also
9648 static checks: you will know about syntax errors and typos as soon as you
9649 run @command{guix system}.
9651 @deftp {Data Type} name-service-switch
9653 This is the data type representation the configuration of libc's name
9654 service switch (NSS). Each field below represents one of the supported
9671 The system databases handled by the NSS. Each of these fields must be a
9672 list of @code{<name-service>} objects (see below).
9676 @deftp {Data Type} name-service
9678 This is the data type representing an actual name service and the
9679 associated lookup action.
9683 A string denoting the name service (@pxref{Services in the NSS
9684 configuration,,, libc, The GNU C Library Reference Manual}).
9686 Note that name services listed here must be visible to nscd. This is
9687 achieved by passing the @code{#:name-services} argument to
9688 @code{nscd-service} the list of packages providing the needed name
9689 services (@pxref{Base Services, @code{nscd-service}}).
9692 An action specified using the @code{lookup-specification} macro
9693 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
9694 Reference Manual}). For example:
9697 (lookup-specification (unavailable => continue)
9698 (success => return))
9703 @node Initial RAM Disk
9704 @subsection Initial RAM Disk
9706 @cindex initial RAM disk (initrd)
9707 @cindex initrd (initial RAM disk)
9708 For bootstrapping purposes, the Linux-Libre kernel is passed an
9709 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
9710 root file system as well as an initialization script. The latter is
9711 responsible for mounting the real root file system, and for loading any
9712 kernel modules that may be needed to achieve that.
9714 The @code{initrd} field of an @code{operating-system} declaration allows
9715 you to specify which initrd you would like to use. The @code{(gnu
9716 system linux-initrd)} module provides two ways to build an initrd: the
9717 high-level @code{base-initrd} procedure, and the low-level
9718 @code{expression->initrd} procedure.
9720 The @code{base-initrd} procedure is intended to cover most common uses.
9721 For example, if you want to add a bunch of kernel modules to be loaded
9722 at boot time, you can define the @code{initrd} field of the operating
9723 system declaration like this:
9726 (initrd (lambda (file-systems . rest)
9727 ;; Create a standard initrd that has modules "foo.ko"
9728 ;; and "bar.ko", as well as their dependencies, in
9729 ;; addition to the modules available by default.
9730 (apply base-initrd file-systems
9731 #:extra-modules '("foo" "bar")
9735 The @code{base-initrd} procedure also handles common use cases that
9736 involves using the system as a QEMU guest, or as a ``live'' system with
9737 volatile root file system.
9739 The initial RAM disk produced by @code{base-initrd} honors several
9740 options passed on the Linux kernel command line (that is, arguments
9741 passed @i{via} the @code{linux} command of GRUB, or the
9742 @code{-append} option) of QEMU, notably:
9745 @item --load=@var{boot}
9746 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
9747 program, once it has mounted the root file system.
9749 GuixSD uses this option to yield control to a boot program that runs the
9750 service activation programs and then spawns the GNU@tie{}Shepherd, the
9751 initialization system.
9753 @item --root=@var{root}
9754 Mount @var{root} as the root file system. @var{root} can be a
9755 device name like @code{/dev/sda1}, a partition label, or a partition
9758 @item --system=@var{system}
9759 Have @file{/run/booted-system} and @file{/run/current-system} point to
9762 @item modprobe.blacklist=@var{modules}@dots{}
9763 @cindex module, black-listing
9764 @cindex black list, of kernel modules
9765 Instruct the initial RAM disk as well as the @command{modprobe} command
9766 (from the kmod package) to refuse to load @var{modules}. @var{modules}
9767 must be a comma-separated list of module names---e.g.,
9768 @code{usbkbd,9pnet}.
9771 Start a read-eval-print loop (REPL) from the initial RAM disk before it
9772 tries to load kernel modules and to mount the root file system. Our
9773 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
9774 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
9775 Manual}, for more information on Guile's REPL.
9779 Now that you know all the features that initial RAM disks produced by
9780 @code{base-initrd} provide, here is how to use it and customize it
9783 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
9784 [#:qemu-networking? #f] [#:virtio? #t] [#:volatile-root? #f] @
9785 [#:extra-modules '()] [#:mapped-devices '()]
9786 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
9787 a list of file systems to be mounted by the initrd, possibly in addition to
9788 the root file system specified on the kernel command line via @code{--root}.
9789 @var{mapped-devices} is a list of device mappings to realize before
9790 @var{file-systems} are mounted (@pxref{Mapped Devices}).
9792 When @var{qemu-networking?} is true, set up networking with the standard QEMU
9793 parameters. When @var{virtio?} is true, load additional modules so that the
9794 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
9796 When @var{volatile-root?} is true, the root file system is writable but any changes
9799 The initrd is automatically populated with all the kernel modules necessary
9800 for @var{file-systems} and for the given options. However, additional kernel
9801 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
9802 loaded at boot time in the order in which they appear.
9805 Needless to say, the initrds we produce and use embed a
9806 statically-linked Guile, and the initialization program is a Guile
9807 program. That gives a lot of flexibility. The
9808 @code{expression->initrd} procedure builds such an initrd, given the
9809 program to run in that initrd.
9811 @deffn {Monadic Procedure} expression->initrd @var{exp} @
9812 [#:guile %guile-static-stripped] [#:name "guile-initrd"] @
9814 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
9815 containing @var{guile} and that evaluates @var{exp}, a G-expression,
9816 upon booting. All the derivations referenced by @var{exp} are
9817 automatically copied to the initrd.
9819 @var{modules} is a list of Guile module names to be embedded in the
9823 @node GRUB Configuration
9824 @subsection GRUB Configuration
9829 The operating system uses GNU@tie{}GRUB as its boot loader
9830 (@pxref{Overview, overview of GRUB,, grub, GNU GRUB Manual}). It is
9831 configured using a @code{grub-configuration} declaration. This data type
9832 is exported by the @code{(gnu system grub)} module and described below.
9834 @deftp {Data Type} grub-configuration
9835 The type of a GRUB configuration declaration.
9840 This is a string denoting the boot device. It must be a device name
9841 understood by the @command{grub-install} command, such as
9842 @code{/dev/sda} or @code{(hd0)} (@pxref{Invoking grub-install,,, grub,
9845 @item @code{menu-entries} (default: @code{()})
9846 A possibly empty list of @code{menu-entry} objects (see below), denoting
9847 entries to appear in the GRUB boot menu, in addition to the current
9848 system entry and the entry pointing to previous system generations.
9850 @item @code{default-entry} (default: @code{0})
9851 The index of the default boot menu entry. Index 0 is for the entry of the
9854 @item @code{timeout} (default: @code{5})
9855 The number of seconds to wait for keyboard input before booting. Set to
9856 0 to boot immediately, and to -1 to wait indefinitely.
9858 @item @code{theme} (default: @var{%default-theme})
9859 The @code{grub-theme} object describing the theme to use.
9864 Should you want to list additional boot menu entries @i{via} the
9865 @code{menu-entries} field above, you will need to create them with the
9866 @code{menu-entry} form:
9868 @deftp {Data Type} menu-entry
9869 The type of an entry in the GRUB boot menu.
9874 The label to show in the menu---e.g., @code{"GNU"}.
9877 The Linux kernel to boot.
9879 @item @code{linux-arguments} (default: @code{()})
9880 The list of extra Linux kernel command-line arguments---e.g.,
9881 @code{("console=ttyS0")}.
9884 A G-Expression or string denoting the file name of the initial RAM disk
9885 to use (@pxref{G-Expressions}).
9890 @c FIXME: Write documentation once it's stable.
9891 Themes are created using the @code{grub-theme} form, which is not
9894 @defvr {Scheme Variable} %default-theme
9895 This is the default GRUB theme used by the operating system, with a
9896 fancy background image displaying the GNU and Guix logos.
9900 @node Invoking guix system
9901 @subsection Invoking @code{guix system}
9903 Once you have written an operating system declaration as seen in the
9904 previous section, it can be @dfn{instantiated} using the @command{guix
9905 system} command. The synopsis is:
9908 guix system @var{options}@dots{} @var{action} @var{file}
9911 @var{file} must be the name of a file containing an
9912 @code{operating-system} declaration. @var{action} specifies how the
9913 operating system is instantiated. Currently the following values are
9918 Build the operating system described in @var{file}, activate it, and
9919 switch to it@footnote{This action is usable only on systems already
9922 This effects all the configuration specified in @var{file}: user
9923 accounts, system services, global package list, setuid programs, etc.
9924 The command starts system services specified in @var{file} that are not
9925 currently running; if a service is currently running, it does not
9926 attempt to upgrade it since this would not be possible without stopping it
9929 It also adds a GRUB menu entry for the new OS configuration, and moves
9930 entries for older configurations to a submenu---unless
9931 @option{--no-grub} is passed.
9934 @c The paragraph below refers to the problem discussed at
9935 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
9936 It is highly recommended to run @command{guix pull} once before you run
9937 @command{guix system reconfigure} for the first time (@pxref{Invoking
9938 guix pull}). Failing to do that you would see an older version of Guix
9939 once @command{reconfigure} has completed.
9943 Build the derivation of the operating system, which includes all the
9944 configuration files and programs needed to boot and run the system.
9945 This action does not actually install anything.
9948 Populate the given directory with all the files necessary to run the
9949 operating system specified in @var{file}. This is useful for first-time
9950 installations of GuixSD. For instance:
9953 guix system init my-os-config.scm /mnt
9956 copies to @file{/mnt} all the store items required by the configuration
9957 specified in @file{my-os-config.scm}. This includes configuration
9958 files, packages, and so on. It also creates other essential files
9959 needed for the system to operate correctly---e.g., the @file{/etc},
9960 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
9962 This command also installs GRUB on the device specified in
9963 @file{my-os-config}, unless the @option{--no-grub} option was passed.
9966 @cindex virtual machine
9968 @anchor{guix system vm}
9969 Build a virtual machine that contains the operating system declared in
9970 @var{file}, and return a script to run that virtual machine (VM).
9971 Arguments given to the script are passed to QEMU.
9973 The VM shares its store with the host system.
9975 Additional file systems can be shared between the host and the VM using
9976 the @code{--share} and @code{--expose} command-line options: the former
9977 specifies a directory to be shared with write access, while the latter
9978 provides read-only access to the shared directory.
9980 The example below creates a VM in which the user's home directory is
9981 accessible read-only, and where the @file{/exchange} directory is a
9982 read-write mapping of @file{$HOME/tmp} on the host:
9985 guix system vm my-config.scm \
9986 --expose=$HOME --share=$HOME/tmp=/exchange
9989 On GNU/Linux, the default is to boot directly to the kernel; this has
9990 the advantage of requiring only a very tiny root disk image since the
9991 store of the host can then be mounted.
9993 The @code{--full-boot} option forces a complete boot sequence, starting
9994 with the bootloader. This requires more disk space since a root image
9995 containing at least the kernel, initrd, and bootloader data files must
9996 be created. The @code{--image-size} option can be used to specify the
10001 Return a virtual machine or disk image of the operating system declared
10002 in @var{file} that stands alone. Use the @option{--image-size} option
10003 to specify the size of the image.
10005 When using @code{vm-image}, the returned image is in qcow2 format, which
10006 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
10007 for more information on how to run the image in a virtual machine.
10009 When using @code{disk-image}, a raw disk image is produced; it can be
10010 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
10011 the device corresponding to a USB stick, one can copy the image to it
10012 using the following command:
10015 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
10019 Return a script to run the operating system declared in @var{file}
10020 within a container. Containers are a set of lightweight isolation
10021 mechanisms provided by the kernel Linux-libre. Containers are
10022 substantially less resource-demanding than full virtual machines since
10023 the kernel, shared objects, and other resources can be shared with the
10024 host system; this also means they provide thinner isolation.
10026 Currently, the script must be run as root in order to support more than
10027 a single user and group. The container shares its store with the host
10030 As with the @code{vm} action (@pxref{guix system vm}), additional file
10031 systems to be shared between the host and container can be specified
10032 using the @option{--share} and @option{--expose} options:
10035 guix system container my-config.scm \
10036 --expose=$HOME --share=$HOME/tmp=/exchange
10040 This option requires Linux-libre 3.19 or newer.
10045 @var{options} can contain any of the common build options (@pxref{Common
10046 Build Options}). In addition, @var{options} can contain one of the
10050 @item --system=@var{system}
10051 @itemx -s @var{system}
10052 Attempt to build for @var{system} instead of the host system type.
10053 This works as per @command{guix build} (@pxref{Invoking guix build}).
10057 Return the derivation file name of the given operating system without
10060 @item --image-size=@var{size}
10061 For the @code{vm-image} and @code{disk-image} actions, create an image
10062 of the given @var{size}. @var{size} may be a number of bytes, or it may
10063 include a unit as a suffix (@pxref{Block size, size specifications,,
10064 coreutils, GNU Coreutils}).
10066 @item --on-error=@var{strategy}
10067 Apply @var{strategy} when an error occurs when reading @var{file}.
10068 @var{strategy} may be one of the following:
10071 @item nothing-special
10072 Report the error concisely and exit. This is the default strategy.
10075 Likewise, but also display a backtrace.
10078 Report the error and enter Guile's debugger. From there, you can run
10079 commands such as @code{,bt} to get a backtrace, @code{,locals} to
10080 display local variable values, and more generally inspect the state of the
10081 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
10082 a list of available debugging commands.
10086 Note that all the actions above, except @code{build} and @code{init},
10087 rely on KVM support in the Linux-Libre kernel. Specifically, the
10088 machine should have hardware virtualization support, the corresponding
10089 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
10090 must exist and be readable and writable by the user and by the
10091 build users of the daemon.
10093 Once you have built, configured, re-configured, and re-re-configured
10094 your GuixSD installation, you may find it useful to list the operating
10095 system generations available on disk---and that you can choose from the
10100 @item list-generations
10101 List a summary of each generation of the operating system available on
10102 disk, in a human-readable way. This is similar to the
10103 @option{--list-generations} option of @command{guix package}
10104 (@pxref{Invoking guix package}).
10106 Optionally, one can specify a pattern, with the same syntax that is used
10107 in @command{guix package --list-generations}, to restrict the list of
10108 generations displayed. For instance, the following command displays
10109 generations that are up to 10 days old:
10112 $ guix system list-generations 10d
10117 The @command{guix system} command has even more to offer! The following
10118 sub-commands allow you to visualize how your system services relate to
10121 @anchor{system-extension-graph}
10124 @item extension-graph
10125 Emit in Dot/Graphviz format to standard output the @dfn{service
10126 extension graph} of the operating system defined in @var{file}
10127 (@pxref{Service Composition}, for more information on service
10133 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
10136 produces a PDF file showing the extension relations among services.
10138 @anchor{system-shepherd-graph}
10139 @item shepherd-graph
10140 Emit in Dot/Graphviz format to standard output the @dfn{dependency
10141 graph} of shepherd services of the operating system defined in
10142 @var{file}. @xref{Shepherd Services}, for more information and for an
10147 @node Running GuixSD in a VM
10148 @subsection Running GuixSD in a Virtual Machine
10150 One way to run GuixSD in a virtual machine (VM) is to build a GuixSD
10151 virtual machine image using @command{guix system vm-image}
10152 (@pxref{Invoking guix system}). The returned image is in qcow2 format,
10153 which the @uref{http://qemu.org/, QEMU emulator} can efficiently use.
10155 To run the image in QEMU, copy it out of the store (@pxref{The Store})
10156 and give yourself permission to write to the copy. When invoking QEMU,
10157 you must choose a system emulator that is suitable for your hardware
10158 platform. Here is a minimal QEMU invocation that will boot the result
10159 of @command{guix system vm-image} on x86_64 hardware:
10162 $ qemu-system-x86_64 \
10163 -net user -net nic,model=virtio \
10164 -enable-kvm -m 256 /tmp/qemu-image
10167 Here is what each of these options means:
10170 @item qemu-system-x86_64
10171 This specifies the hardware platform to emulate. This should match the
10175 Enable the unprivileged user-mode network stack. The guest OS can
10176 access the host but not vice versa. This is the simplest way to get the
10177 guest OS online. If you do not choose a network stack, the boot will
10180 @item -net nic,model=virtio
10181 You must create a network interface of a given model. If you do not
10182 create a NIC, the boot will fail. Assuming your hardware platform is
10183 x86_64, you can get a list of available NIC models by running
10184 @command{qemu-system-x86_64 -net nic,model=help}.
10187 If your system has hardware virtualization extensions, enabling the
10188 virtual machine support (KVM) of the Linux kernel will make things run
10192 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
10193 which may be insufficent for some operations.
10195 @item /tmp/qemu-image
10196 The file name of the qcow2 image.
10199 @node Defining Services
10200 @subsection Defining Services
10202 The previous sections show the available services and how one can combine
10203 them in an @code{operating-system} declaration. But how do we define
10204 them in the first place? And what is a service anyway?
10207 * Service Composition:: The model for composing services.
10208 * Service Types and Services:: Types and services.
10209 * Service Reference:: API reference.
10210 * Shepherd Services:: A particular type of service.
10213 @node Service Composition
10214 @subsubsection Service Composition
10218 Here we define a @dfn{service} as, broadly, something that extends the
10219 functionality of the operating system. Often a service is a process---a
10220 @dfn{daemon}---started when the system boots: a secure shell server, a
10221 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
10222 whose execution can be triggered by another daemon---e.g., an FTP server
10223 started by @command{inetd} or a D-Bus service activated by
10224 @command{dbus-daemon}. Occasionally, a service does not map to a
10225 daemon. For instance, the ``account'' service collects user accounts
10226 and makes sure they exist when the system runs; the ``udev'' service
10227 collects device management rules and makes them available to the eudev
10228 daemon; the @file{/etc} service populates the @file{/etc} directory
10231 @cindex service extensions
10232 GuixSD services are connected by @dfn{extensions}. For instance, the
10233 secure shell service @emph{extends} the Shepherd---the GuixSD
10234 initialization system, running as PID@tie{}1---by giving it the command
10235 lines to start and stop the secure shell daemon (@pxref{Networking
10236 Services, @code{lsh-service}}); the UPower service extends the D-Bus
10237 service by passing it its @file{.service} specification, and extends the
10238 udev service by passing it device management rules (@pxref{Desktop
10239 Services, @code{upower-service}}); the Guix daemon service extends the
10240 Shepherd by passing it the command lines to start and stop the daemon,
10241 and extends the account service by passing it a list of required build
10242 user accounts (@pxref{Base Services}).
10244 All in all, services and their ``extends'' relations form a directed
10245 acyclic graph (DAG). If we represent services as boxes and extensions
10246 as arrows, a typical system might provide something like this:
10248 @image{images/service-graph,,5in,Typical service extension graph.}
10250 @cindex system service
10251 At the bottom, we see the @dfn{system service}, which produces the
10252 directory containing everything to run and boot the system, as returned
10253 by the @command{guix system build} command. @xref{Service Reference},
10254 to learn about the other service types shown here.
10255 @xref{system-extension-graph, the @command{guix system extension-graph}
10256 command}, for information on how to generate this representation for a
10257 particular operating system definition.
10259 @cindex service types
10260 Technically, developers can define @dfn{service types} to express these
10261 relations. There can be any number of services of a given type on the
10262 system---for instance, a system running two instances of the GNU secure
10263 shell server (lsh) has two instances of @var{lsh-service-type}, with
10264 different parameters.
10266 The following section describes the programming interface for service
10267 types and services.
10269 @node Service Types and Services
10270 @subsubsection Service Types and Services
10272 A @dfn{service type} is a node in the DAG described above. Let us start
10273 with a simple example, the service type for the Guix build daemon
10274 (@pxref{Invoking guix-daemon}):
10277 (define guix-service-type
10281 (list (service-extension shepherd-root-service-type guix-shepherd-service)
10282 (service-extension account-service-type guix-accounts)
10283 (service-extension activation-service-type guix-activation)))))
10287 It defines two things:
10291 A name, whose sole purpose is to make inspection and debugging easier.
10294 A list of @dfn{service extensions}, where each extension designates the
10295 target service type and a procedure that, given the parameters of the
10296 service, returns a list of objects to extend the service of that type.
10298 Every service type has at least one service extension. The only
10299 exception is the @dfn{boot service type}, which is the ultimate service.
10302 In this example, @var{guix-service-type} extends three services:
10305 @item shepherd-root-service-type
10306 The @var{guix-shepherd-service} procedure defines how the Shepherd
10307 service is extended. Namely, it returns a @code{<shepherd-service>}
10308 object that defines how @command{guix-daemon} is started and stopped
10309 (@pxref{Shepherd Services}).
10311 @item account-service-type
10312 This extension for this service is computed by @var{guix-accounts},
10313 which returns a list of @code{user-group} and @code{user-account}
10314 objects representing the build user accounts (@pxref{Invoking
10317 @item activation-service-type
10318 Here @var{guix-activation} is a procedure that returns a gexp, which is
10319 a code snippet to run at ``activation time''---e.g., when the service is
10323 A service of this type is instantiated like this:
10326 (service guix-service-type
10327 (guix-configuration
10329 (use-substitutes? #f)))
10332 The second argument to the @code{service} form is a value representing
10333 the parameters of this specific service instance.
10334 @xref{guix-configuration-type, @code{guix-configuration}}, for
10335 information about the @code{guix-configuration} data type.
10337 @var{guix-service-type} is quite simple because it extends other
10338 services but is not extensible itself.
10340 @c @subsubsubsection Extensible Service Types
10342 The service type for an @emph{extensible} service looks like this:
10345 (define udev-service-type
10346 (service-type (name 'udev)
10348 (list (service-extension shepherd-root-service-type
10349 udev-shepherd-service)))
10351 (compose concatenate) ;concatenate the list of rules
10352 (extend (lambda (config rules)
10354 (($ <udev-configuration> udev initial-rules)
10355 (udev-configuration
10356 (udev udev) ;the udev package to use
10357 (rules (append initial-rules rules)))))))))
10360 This is the service type for the
10361 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
10362 management daemon}. Compared to the previous example, in addition to an
10363 extension of @var{shepherd-root-service-type}, we see two new fields:
10367 This is the procedure to @dfn{compose} the list of extensions to
10368 services of this type.
10370 Services can extend the udev service by passing it lists of rules; we
10371 compose those extensions simply by concatenating them.
10374 This procedure defines how the value of the service is @dfn{extended} with
10375 the composition of the extensions.
10377 Udev extensions are composed into a list of rules, but the udev service
10378 value is itself a @code{<udev-configuration>} record. So here, we
10379 extend that record by appending the list of rules it contains to the
10380 list of contributed rules.
10383 There can be only one instance of an extensible service type such as
10384 @var{udev-service-type}. If there were more, the
10385 @code{service-extension} specifications would be ambiguous.
10387 Still here? The next section provides a reference of the programming
10388 interface for services.
10390 @node Service Reference
10391 @subsubsection Service Reference
10393 We have seen an overview of service types (@pxref{Service Types and
10394 Services}). This section provides a reference on how to manipulate
10395 services and service types. This interface is provided by the
10396 @code{(gnu services)} module.
10398 @deffn {Scheme Procedure} service @var{type} @var{value}
10399 Return a new service of @var{type}, a @code{<service-type>} object (see
10400 below.) @var{value} can be any object; it represents the parameters of
10401 this particular service instance.
10404 @deffn {Scheme Procedure} service? @var{obj}
10405 Return true if @var{obj} is a service.
10408 @deffn {Scheme Procedure} service-kind @var{service}
10409 Return the type of @var{service}---i.e., a @code{<service-type>} object.
10412 @deffn {Scheme Procedure} service-parameters @var{service}
10413 Return the value associated with @var{service}. It represents its
10417 Here is an example of how a service is created and manipulated:
10421 (service nginx-service-type
10422 (nginx-configuration
10424 (log-directory log-directory)
10425 (run-directory run-directory)
10426 (file config-file))))
10431 (eq? (service-kind s) nginx-service-type)
10435 The @code{modify-services} form provides a handy way to change the
10436 parameters of some of the services of a list such as
10437 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
10438 evalutes to a list of services. Of course, you could always use
10439 standard list combinators such as @code{map} and @code{fold} to do that
10440 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
10441 @code{modify-services} simply provides a more concise form for this
10444 @deffn {Scheme Syntax} modify-services @var{services} @
10445 (@var{type} @var{variable} => @var{body}) @dots{}
10447 Modify the services listed in @var{services} according to the given
10448 clauses. Each clause has the form:
10451 (@var{type} @var{variable} => @var{body})
10454 where @var{type} is a service type---e.g.,
10455 @code{guix-service-type}---and @var{variable} is an identifier that is
10456 bound within the @var{body} to the service parameters---e.g., a
10457 @code{guix-configuration} instance---of the original service of that
10460 The @var{body} should evaluate to the new service parameters, which will
10461 be used to configure the new service. This new service will replace the
10462 original in the resulting list. Because a service's service parameters
10463 are created using @code{define-record-type*}, you can write a succint
10464 @var{body} that evaluates to the new service parameters by using the
10465 @code{inherit} feature that @code{define-record-type*} provides.
10467 @xref{Using the Configuration System}, for example usage.
10471 Next comes the programming interface for service types. This is
10472 something you want to know when writing new service definitions, but not
10473 necessarily when simply looking for ways to customize your
10474 @code{operating-system} declaration.
10476 @deftp {Data Type} service-type
10477 @cindex service type
10478 This is the representation of a @dfn{service type} (@pxref{Service Types
10483 This is a symbol, used only to simplify inspection and debugging.
10485 @item @code{extensions}
10486 A non-empty list of @code{<service-extension>} objects (see below).
10488 @item @code{compose} (default: @code{#f})
10489 If this is @code{#f}, then the service type denotes services that cannot
10490 be extended---i.e., services that do not receive ``values'' from other
10493 Otherwise, it must be a one-argument procedure. The procedure is called
10494 by @code{fold-services} and is passed a list of values collected from
10495 extensions. It must return a value that is a valid parameter value for
10496 the service instance.
10498 @item @code{extend} (default: @code{#f})
10499 If this is @code{#f}, services of this type cannot be extended.
10501 Otherwise, it must be a two-argument procedure: @code{fold-services}
10502 calls it, passing it the initial value of the service as the first argument
10503 and the result of applying @code{compose} to the extension values as the
10507 @xref{Service Types and Services}, for examples.
10510 @deffn {Scheme Procedure} service-extension @var{target-type} @
10512 Return a new extension for services of type @var{target-type}.
10513 @var{compute} must be a one-argument procedure: @code{fold-services}
10514 calls it, passing it the value associated with the service that provides
10515 the extension; it must return a valid value for the target service.
10518 @deffn {Scheme Procedure} service-extension? @var{obj}
10519 Return true if @var{obj} is a service extension.
10522 At the core of the service abstraction lies the @code{fold-services}
10523 procedure, which is responsible for ``compiling'' a list of services
10524 down to a single directory that contains everything needed to boot and
10525 run the system---the directory shown by the @command{guix system build}
10526 command (@pxref{Invoking guix system}). In essence, it propagates
10527 service extensions down the service graph, updating each node parameters
10528 on the way, until it reaches the root node.
10530 @deffn {Scheme Procedure} fold-services @var{services} @
10531 [#:target-type @var{system-service-type}]
10532 Fold @var{services} by propagating their extensions down to the root of
10533 type @var{target-type}; return the root service adjusted accordingly.
10536 Lastly, the @code{(gnu services)} module also defines several essential
10537 service types, some of which are listed below.
10539 @defvr {Scheme Variable} system-service-type
10540 This is the root of the service graph. It produces the system directory
10541 as returned by the @command{guix system build} command.
10544 @defvr {Scheme Variable} boot-service-type
10545 The type of the ``boot service'', which produces the @dfn{boot script}.
10546 The boot script is what the initial RAM disk runs when booting.
10549 @defvr {Scheme Variable} etc-service-type
10550 The type of the @file{/etc} service. This service can be extended by
10551 passing it name/file tuples such as:
10554 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
10557 In this example, the effect would be to add an @file{/etc/issue} file
10558 pointing to the given file.
10561 @defvr {Scheme Variable} setuid-program-service-type
10562 Type for the ``setuid-program service''. This service collects lists of
10563 executable file names, passed as gexps, and adds them to the set of
10564 setuid-root programs on the system (@pxref{Setuid Programs}).
10567 @defvr {Scheme Variable} profile-service-type
10568 Type of the service that populates the @dfn{system profile}---i.e., the
10569 programs under @file{/run/current-system/profile}. Other services can
10570 extend it by passing it lists of packages to add to the system profile.
10574 @node Shepherd Services
10575 @subsubsection Shepherd Services
10578 @cindex init system
10579 The @code{(gnu services shepherd)} module provides a way to define
10580 services managed by the GNU@tie{}Shepherd, which is the GuixSD
10581 initialization system---the first process that is started when the
10582 system boots, also known as PID@tie{}1
10583 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
10585 Services in the Shepherd can depend on each other. For instance, the
10586 SSH daemon may need to be started after the syslog daemon has been
10587 started, which in turn can only happen once all the file systems have
10588 been mounted. The simple operating system defined earlier (@pxref{Using
10589 the Configuration System}) results in a service graph like this:
10591 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
10593 You can actually generate such a graph for any operating system
10594 definition using the @command{guix system shepherd-graph} command
10595 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
10597 The @var{%shepherd-root-service} is a service object representing
10598 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
10599 by passing it lists of @code{<shepherd-service>} objects.
10601 @deftp {Data Type} shepherd-service
10602 The data type representing a service managed by the Shepherd.
10605 @item @code{provision}
10606 This is a list of symbols denoting what the service provides.
10608 These are the names that may be passed to @command{herd start},
10609 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
10610 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
10611 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
10613 @item @code{requirements} (default: @code{'()})
10614 List of symbols denoting the Shepherd services this one depends on.
10616 @item @code{respawn?} (default: @code{#t})
10617 Whether to restart the service when it stops, for instance when the
10618 underlying process dies.
10621 @itemx @code{stop} (default: @code{#~(const #f)})
10622 The @code{start} and @code{stop} fields refer to the Shepherd's
10623 facilities to start and stop processes (@pxref{Service De- and
10624 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
10625 G-expressions that get expanded in the Shepherd configuration file
10626 (@pxref{G-Expressions}).
10628 @item @code{documentation}
10629 A documentation string, as shown when running:
10632 herd doc @var{service-name}
10635 where @var{service-name} is one of the symbols in @var{provision}
10636 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
10638 @item @code{modules} (default: @var{%default-modules})
10639 This is the list of modules that must be in scope when @code{start} and
10640 @code{stop} are evaluated.
10642 @item @code{imported-modules} (default: @var{%default-imported-modules})
10643 This is the list of modules to import in the execution environment of
10649 @defvr {Scheme Variable} shepherd-root-service-type
10650 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
10652 This is the service type that extensions target when they want to create
10653 shepherd services (@pxref{Service Types and Services}, for an example).
10654 Each extension must pass a list of @code{<shepherd-service>}.
10657 @defvr {Scheme Variable} %shepherd-root-service
10658 This service represents PID@tie{}1.
10662 @node Installing Debugging Files
10663 @section Installing Debugging Files
10665 @cindex debugging files
10666 Program binaries, as produced by the GCC compilers for instance, are
10667 typically written in the ELF format, with a section containing
10668 @dfn{debugging information}. Debugging information is what allows the
10669 debugger, GDB, to map binary code to source code; it is required to
10670 debug a compiled program in good conditions.
10672 The problem with debugging information is that is takes up a fair amount
10673 of disk space. For example, debugging information for the GNU C Library
10674 weighs in at more than 60 MiB. Thus, as a user, keeping all the
10675 debugging info of all the installed programs is usually not an option.
10676 Yet, space savings should not come at the cost of an impediment to
10677 debugging---especially in the GNU system, which should make it easier
10678 for users to exert their computing freedom (@pxref{GNU Distribution}).
10680 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
10681 mechanism that allows users to get the best of both worlds: debugging
10682 information can be stripped from the binaries and stored in separate
10683 files. GDB is then able to load debugging information from those files,
10684 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
10687 The GNU distribution takes advantage of this by storing debugging
10688 information in the @code{lib/debug} sub-directory of a separate package
10689 output unimaginatively called @code{debug} (@pxref{Packages with
10690 Multiple Outputs}). Users can choose to install the @code{debug} output
10691 of a package when they need it. For instance, the following command
10692 installs the debugging information for the GNU C Library and for GNU
10696 guix package -i glibc:debug guile:debug
10699 GDB must then be told to look for debug files in the user's profile, by
10700 setting the @code{debug-file-directory} variable (consider setting it
10701 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
10705 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
10708 From there on, GDB will pick up debugging information from the
10709 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
10711 In addition, you will most likely want GDB to be able to show the source
10712 code being debugged. To do that, you will have to unpack the source
10713 code of the package of interest (obtained with @code{guix build
10714 --source}, @pxref{Invoking guix build}), and to point GDB to that source
10715 directory using the @code{directory} command (@pxref{Source Path,
10716 @code{directory},, gdb, Debugging with GDB}).
10718 @c XXX: keep me up-to-date
10719 The @code{debug} output mechanism in Guix is implemented by the
10720 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
10721 opt-in---debugging information is available only for the packages
10722 with definitions explicitly declaring a @code{debug} output. This may be
10723 changed to opt-out in the future if our build farm servers can handle
10724 the load. To check whether a package has a @code{debug} output, use
10725 @command{guix package --list-available} (@pxref{Invoking guix package}).
10728 @node Security Updates
10729 @section Security Updates
10731 @cindex security updates
10732 @cindex security vulnerabilities
10733 Occasionally, important security vulnerabilities are discovered in software
10734 packages and must be patched. Guix developers try hard to keep track of
10735 known vulnerabilities and to apply fixes as soon as possible in the
10736 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
10737 containing only security updates.) The @command{guix lint} tool helps
10738 developers find out about vulnerable versions of software packages in the
10743 gnu/packages/base.scm:652:2: glibc-2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
10744 gnu/packages/gcc.scm:334:2: gcc-4.9.3: probably vulnerable to CVE-2015-5276
10745 gnu/packages/image.scm:312:2: openjpeg-2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
10749 @xref{Invoking guix lint}, for more information.
10752 As of version @value{VERSION}, the feature described below is considered
10756 Guix follows a functional
10757 package management discipline (@pxref{Introduction}), which implies
10758 that, when a package is changed, @emph{every package that depends on it}
10759 must be rebuilt. This can significantly slow down the deployment of
10760 fixes in core packages such as libc or Bash, since basically the whole
10761 distribution would need to be rebuilt. Using pre-built binaries helps
10762 (@pxref{Substitutes}), but deployment may still take more time than
10766 To address this, Guix implements @dfn{grafts}, a mechanism that allows
10767 for fast deployment of critical updates without the costs associated
10768 with a whole-distribution rebuild. The idea is to rebuild only the
10769 package that needs to be patched, and then to ``graft'' it onto packages
10770 explicitly installed by the user and that were previously referring to
10771 the original package. The cost of grafting is typically very low, and
10772 order of magnitudes lower than a full rebuild of the dependency chain.
10774 @cindex replacements of packages, for grafts
10775 For instance, suppose a security update needs to be applied to Bash.
10776 Guix developers will provide a package definition for the ``fixed''
10777 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
10778 Packages}). Then, the original package definition is augmented with a
10779 @code{replacement} field pointing to the package containing the bug fix:
10786 (replacement bash-fixed)))
10789 From there on, any package depending directly or indirectly on Bash---as
10790 reported by @command{guix gc --requisites} (@pxref{Invoking guix
10791 gc})---that is installed is automatically ``rewritten'' to refer to
10792 @var{bash-fixed} instead of @var{bash}. This grafting process takes
10793 time proportional to the size of the package, usually less than a
10794 minute for an ``average'' package on a recent machine. Grafting is
10795 recursive: when an indirect dependency requires grafting, then grafting
10796 ``propagates'' up to the package that the user is installing.
10798 Currently, the graft and the package it replaces (@var{bash-fixed} and
10799 @var{bash} in the example above) must have the exact same @code{name}
10800 and @code{version} fields. This restriction mostly comes from the fact
10801 that grafting works by patching files, including binary files, directly.
10802 Other restrictions may apply: for instance, when adding a graft to a
10803 package providing a shared library, the original shared library and its
10804 replacement must have the same @code{SONAME} and be binary-compatible.
10806 The @option{--no-grafts} command-line option allows you to forcefully
10807 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
10811 guix build bash --no-grafts
10815 returns the store file name of the original Bash, whereas:
10822 returns the store file name of the ``fixed'', replacement Bash. This
10823 allows you to distinguish between the two variants of Bash.
10825 To verify which Bash your whole profile refers to, you can run
10826 (@pxref{Invoking guix gc}):
10829 guix gc -R `readlink -f ~/.guix-profile` | grep bash
10833 @dots{} and compare the store file names that you get with those above.
10834 Likewise for a complete GuixSD system generation:
10837 guix gc -R `guix system build my-config.scm` | grep bash
10840 Lastly, to check which Bash running processes are using, you can use the
10841 @command{lsof} command:
10844 lsof | grep /gnu/store/.*bash
10848 @node Package Modules
10849 @section Package Modules
10851 From a programming viewpoint, the package definitions of the
10852 GNU distribution are provided by Guile modules in the @code{(gnu packages
10853 @dots{})} name space@footnote{Note that packages under the @code{(gnu
10854 packages @dots{})} module name space are not necessarily ``GNU
10855 packages''. This module naming scheme follows the usual Guile module
10856 naming convention: @code{gnu} means that these modules are distributed
10857 as part of the GNU system, and @code{packages} identifies modules that
10858 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
10859 Reference Manual}). For instance, the @code{(gnu packages emacs)}
10860 module exports a variable named @code{emacs}, which is bound to a
10861 @code{<package>} object (@pxref{Defining Packages}).
10863 The @code{(gnu packages @dots{})} module name space is
10864 automatically scanned for packages by the command-line tools. For
10865 instance, when running @code{guix package -i emacs}, all the @code{(gnu
10866 packages @dots{})} modules are scanned until one that exports a package
10867 object whose name is @code{emacs} is found. This package search
10868 facility is implemented in the @code{(gnu packages)} module.
10870 @cindex customization, of packages
10871 @cindex package module search path
10872 Users can store package definitions in modules with different
10873 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
10874 name and module name must match. For instance, the @code{(my-packages
10875 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
10876 relative to the load path specified with @option{--load-path} or
10877 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
10878 guile, GNU Guile Reference Manual}, for details.}. These package definitions
10879 will not be visible by default. Users can invoke commands such as
10880 @command{guix package} and @command{guix build} with the
10881 @code{-e} option so that they know where to find the package. Better
10882 yet, they can use the
10883 @code{-L} option of these commands to make those modules visible
10884 (@pxref{Invoking guix build, @code{--load-path}}), or define the
10885 @code{GUIX_PACKAGE_PATH} environment variable. This environment
10886 variable makes it easy to extend or customize the distribution and is
10887 honored by all the user interfaces.
10889 @defvr {Environment Variable} GUIX_PACKAGE_PATH
10890 This is a colon-separated list of directories to search for additional
10891 package modules. Directories listed in this variable take precedence
10892 over the own modules of the distribution.
10895 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
10896 each package is built based solely on other packages in the
10897 distribution. The root of this dependency graph is a small set of
10898 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
10899 bootstrap)} module. For more information on bootstrapping,
10900 @pxref{Bootstrapping}.
10902 @node Packaging Guidelines
10903 @section Packaging Guidelines
10905 The GNU distribution is nascent and may well lack some of your favorite
10906 packages. This section describes how you can help make the distribution
10907 grow. @xref{Contributing}, for additional information on how you can
10910 Free software packages are usually distributed in the form of
10911 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
10912 all the source files. Adding a package to the distribution means
10913 essentially two things: adding a @dfn{recipe} that describes how to
10914 build the package, including a list of other packages required to build
10915 it, and adding @dfn{package metadata} along with that recipe, such as a
10916 description and licensing information.
10918 In Guix all this information is embodied in @dfn{package definitions}.
10919 Package definitions provide a high-level view of the package. They are
10920 written using the syntax of the Scheme programming language; in fact,
10921 for each package we define a variable bound to the package definition,
10922 and export that variable from a module (@pxref{Package Modules}).
10923 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
10924 creating packages. For more information on package definitions,
10925 @pxref{Defining Packages}.
10927 Once a package definition is in place, stored in a file in the Guix
10928 source tree, it can be tested using the @command{guix build} command
10929 (@pxref{Invoking guix build}). For example, assuming the new package is
10930 called @code{gnew}, you may run this command from the Guix build tree
10931 (@pxref{Running Guix Before It Is Installed}):
10934 ./pre-inst-env guix build gnew --keep-failed
10937 Using @code{--keep-failed} makes it easier to debug build failures since
10938 it provides access to the failed build tree. Another useful
10939 command-line option when debugging is @code{--log-file}, to access the
10942 If the package is unknown to the @command{guix} command, it may be that
10943 the source file contains a syntax error, or lacks a @code{define-public}
10944 clause to export the package variable. To figure it out, you may load
10945 the module from Guile to get more information about the actual error:
10948 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
10951 Once your package builds correctly, please send us a patch
10952 (@pxref{Contributing}). Well, if you need help, we will be happy to
10953 help you too. Once the patch is committed in the Guix repository, the
10954 new package automatically gets built on the supported platforms by
10955 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
10958 @cindex substituter
10959 Users can obtain the new package definition simply by running
10960 @command{guix pull} (@pxref{Invoking guix pull}). When
10961 @code{hydra.gnu.org} is done building the package, installing the
10962 package automatically downloads binaries from there
10963 (@pxref{Substitutes}). The only place where human intervention is
10964 needed is to review and apply the patch.
10968 * Software Freedom:: What may go into the distribution.
10969 * Package Naming:: What's in a name?
10970 * Version Numbers:: When the name is not enough.
10971 * Synopses and Descriptions:: Helping users find the right package.
10972 * Python Modules:: Taming the snake.
10973 * Perl Modules:: Little pearls.
10974 * Java Packages:: Coffee break.
10975 * Fonts:: Fond of fonts.
10978 @node Software Freedom
10979 @subsection Software Freedom
10981 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
10983 The GNU operating system has been developed so that users can have
10984 freedom in their computing. GNU is @dfn{free software}, meaning that
10985 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
10986 essential freedoms}: to run the program, to study and change the program
10987 in source code form, to redistribute exact copies, and to distribute
10988 modified versions. Packages found in the GNU distribution provide only
10989 software that conveys these four freedoms.
10991 In addition, the GNU distribution follow the
10992 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
10993 software distribution guidelines}. Among other things, these guidelines
10994 reject non-free firmware, recommendations of non-free software, and
10995 discuss ways to deal with trademarks and patents.
10997 Some otherwise free upstream package sources contain a small and optional
10998 subset that violates the above guidelines, for instance because this subset
10999 is itself non-free code. When that happens, the offending items are removed
11000 with appropriate patches or code snippets in the @code{origin} form of the
11001 package (@pxref{Defining Packages}). This way, @code{guix
11002 build --source} returns the ``freed'' source rather than the unmodified
11006 @node Package Naming
11007 @subsection Package Naming
11009 A package has actually two names associated with it:
11010 First, there is the name of the @emph{Scheme variable}, the one following
11011 @code{define-public}. By this name, the package can be made known in the
11012 Scheme code, for instance as input to another package. Second, there is
11013 the string in the @code{name} field of a package definition. This name
11014 is used by package management commands such as
11015 @command{guix package} and @command{guix build}.
11017 Both are usually the same and correspond to the lowercase conversion of
11018 the project name chosen upstream, with underscores replaced with
11019 hyphens. For instance, GNUnet is available as @code{gnunet}, and
11020 SDL_net as @code{sdl-net}.
11022 We do not add @code{lib} prefixes for library packages, unless these are
11023 already part of the official project name. But @pxref{Python
11024 Modules} and @ref{Perl Modules} for special rules concerning modules for
11025 the Python and Perl languages.
11027 Font package names are handled differently, @pxref{Fonts}.
11030 @node Version Numbers
11031 @subsection Version Numbers
11033 We usually package only the latest version of a given free software
11034 project. But sometimes, for instance for incompatible library versions,
11035 two (or more) versions of the same package are needed. These require
11036 different Scheme variable names. We use the name as defined
11037 in @ref{Package Naming}
11038 for the most recent version; previous versions use the same name, suffixed
11039 by @code{-} and the smallest prefix of the version number that may
11040 distinguish the two versions.
11042 The name inside the package definition is the same for all versions of a
11043 package and does not contain any version number.
11045 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
11048 (define-public gtk+
11053 (define-public gtk+-2
11056 (version "2.24.20")
11059 If we also wanted GTK+ 3.8.2, this would be packaged as
11061 (define-public gtk+-3.8
11068 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
11069 @c for a discussion of what follows.
11070 @cindex version number, for VCS snapshots
11071 Occasionally, we package snapshots of upstream's version control system
11072 (VCS) instead of formal releases. This should remain exceptional,
11073 because it is up to upstream developers to clarify what the stable
11074 release is. Yet, it is sometimes necessary. So, what should we put in
11075 the @code{version} field?
11077 Clearly, we need to make the commit identifier of the VCS snapshot
11078 visible in the version string, but we also need to make sure that the
11079 version string is monotonically increasing so that @command{guix package
11080 --upgrade} can determine which version is newer. Since commit
11081 identifiers, notably with Git, are not monotonically increasing, we add
11082 a revision number that we increase each time we upgrade to a newer
11083 snapshot. The resulting version string looks like this:
11088 | | `-- upstream commit ID
11090 | `--- Guix package revision
11092 latest upstream version
11095 It is a good idea to strip commit identifiers in the @code{version}
11096 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
11097 aesthetics have a role to play here) as well as problems related to OS
11098 limits such as the maximum shebang length (127 bytes for the Linux
11099 kernel.) It is best to use the full commit identifiers in
11100 @code{origin}s, though, to avoid ambiguities. A typical package
11101 definition may look like this:
11105 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7"))
11107 (version (string-append "0.9-1."
11108 (string-take commit 7)))
11111 (uri (git-reference
11112 (url "git://example.org/my-package.git")
11114 (sha256 (base32 "1mbikn@dots{}"))
11115 (file-name (string-append "my-package-" version
11121 @node Synopses and Descriptions
11122 @subsection Synopses and Descriptions
11124 As we have seen before, each package in GNU@tie{}Guix includes a
11125 synopsis and a description (@pxref{Defining Packages}). Synopses and
11126 descriptions are important: They are what @command{guix package
11127 --search} searches, and a crucial piece of information to help users
11128 determine whether a given package suits their needs. Consequently,
11129 packagers should pay attention to what goes into them.
11131 Synopses must start with a capital letter and must not end with a
11132 period. They must not start with ``a'' or ``the'', which usually does
11133 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
11134 tool that frobs files''. The synopsis should say what the package
11135 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
11136 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
11137 matching a pattern''.
11139 Keep in mind that the synopsis must be meaningful for a very wide
11140 audience. For example, ``Manipulate alignments in the SAM format''
11141 might make sense for a seasoned bioinformatics researcher, but might be
11142 fairly unhelpful or even misleading to a non-specialized audience. It
11143 is a good idea to come up with a synopsis that gives an idea of the
11144 application domain of the package. In this example, this might give
11145 something like ``Manipulate nucleotide sequence alignments'', which
11146 hopefully gives the user a better idea of whether this is what they are
11149 @cindex Texinfo markup, in package descriptions
11150 Descriptions should take between five and ten lines. Use full
11151 sentences, and avoid using acronyms without first introducing them.
11152 Descriptions can include Texinfo markup, which is useful to introduce
11153 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
11154 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
11155 should be careful when using some characters for example @samp{@@} and
11156 curly braces which are the basic special characters in Texinfo
11157 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
11158 such as @command{guix package --show} take care of rendering it
11161 Synopses and descriptions are translated by volunteers
11162 @uref{http://translationproject.org/domain/guix-packages.html, at the
11163 Translation Project} so that as many users as possible can read them in
11164 their native language. User interfaces search them and display them in
11165 the language specified by the current locale.
11167 Translation is a lot of work so, as a packager, please pay even more
11168 attention to your synopses and descriptions as every change may entail
11169 additional work for translators. In order to help them, it is possible
11170 to make recommendations or instructions visible to them by inserting
11171 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
11175 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
11176 (description "ARandR is designed to provide a simple visual front end
11177 for the X11 resize-and-rotate (RandR) extension. @dots{}")
11181 @node Python Modules
11182 @subsection Python Modules
11184 We currently package Python 2 and Python 3, under the Scheme variable names
11185 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
11186 To avoid confusion and naming clashes with other programming languages, it
11187 seems desirable that the name of a package for a Python module contains
11188 the word @code{python}.
11190 Some modules are compatible with only one version of Python, others with both.
11191 If the package Foo compiles only with Python 3, we name it
11192 @code{python-foo}; if it compiles only with Python 2, we name it
11193 @code{python2-foo}. If it is compatible with both versions, we create two
11194 packages with the corresponding names.
11196 If a project already contains the word @code{python}, we drop this;
11197 for instance, the module python-dateutil is packaged under the names
11198 @code{python-dateutil} and @code{python2-dateutil}. If the project name
11199 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
11204 @subsection Perl Modules
11206 Perl programs standing for themselves are named as any other package,
11207 using the lowercase upstream name.
11208 For Perl packages containing a single class, we use the lowercase class name,
11209 replace all occurrences of @code{::} by dashes and prepend the prefix
11211 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
11212 Modules containing several classes keep their lowercase upstream name and
11213 are also prepended by @code{perl-}. Such modules tend to have the word
11214 @code{perl} somewhere in their name, which gets dropped in favor of the
11215 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
11218 @node Java Packages
11219 @subsection Java Packages
11221 Java programs standing for themselves are named as any other package,
11222 using the lowercase upstream name.
11224 To avoid confusion and naming clashes with other programming languages,
11225 it is desirable that the name of a package for a Java package is
11226 prefixed with @code{java-}. If a project already contains the word
11227 @code{java}, we drop this; for instance, the package @code{ngsjava} is
11228 packaged under the name @code{java-ngs}.
11230 For Java packages containing a single class or a small class hierarchy,
11231 we use the lowercase class name, replace all occurrences of @code{.} by
11232 dashes and prepend the prefix @code{java-}. So the class
11233 @code{apache.commons.cli} becomes package
11234 @code{java-apache-commons-cli}.
11240 For fonts that are in general not installed by a user for typesetting
11241 purposes, or that are distributed as part of a larger software package,
11242 we rely on the general packaging rules for software; for instance, this
11243 applies to the fonts delivered as part of the X.Org system or fonts that
11244 are part of TeX Live.
11246 To make it easier for a user to search for fonts, names for other packages
11247 containing only fonts are constructed as follows, independently of the
11248 upstream package name.
11250 The name of a package containing only one font family starts with
11251 @code{font-}; it is followed by the foundry name and a dash @code{-}
11252 if the foundry is known, and the font family name, in which spaces are
11253 replaced by dashes (and as usual, all upper case letters are transformed
11255 For example, the Gentium font family by SIL is packaged under the name
11256 @code{font-sil-gentium}.
11258 For a package containing several font families, the name of the collection
11259 is used in the place of the font family name.
11260 For instance, the Liberation fonts consist of three families,
11261 Liberation Sans, Liberation Serif and Liberation Mono.
11262 These could be packaged separately under the names
11263 @code{font-liberation-sans} and so on; but as they are distributed together
11264 under a common name, we prefer to package them together as
11265 @code{font-liberation}.
11267 In the case where several formats of the same font family or font collection
11268 are packaged separately, a short form of the format, prepended by a dash,
11269 is added to the package name. We use @code{-ttf} for TrueType fonts,
11270 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
11275 @node Bootstrapping
11276 @section Bootstrapping
11278 @c Adapted from the ELS 2013 paper.
11280 @cindex bootstrapping
11282 Bootstrapping in our context refers to how the distribution gets built
11283 ``from nothing''. Remember that the build environment of a derivation
11284 contains nothing but its declared inputs (@pxref{Introduction}). So
11285 there's an obvious chicken-and-egg problem: how does the first package
11286 get built? How does the first compiler get compiled? Note that this is
11287 a question of interest only to the curious hacker, not to the regular
11288 user, so you can shamelessly skip this section if you consider yourself
11289 a ``regular user''.
11291 @cindex bootstrap binaries
11292 The GNU system is primarily made of C code, with libc at its core. The
11293 GNU build system itself assumes the availability of a Bourne shell and
11294 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
11295 `grep'. Furthermore, build programs---programs that run
11296 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
11297 (@pxref{Derivations}). Consequently, to be able to build anything at
11298 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
11299 Binutils, libc, and the other packages mentioned above---the
11300 @dfn{bootstrap binaries}.
11302 These bootstrap binaries are ``taken for granted'', though we can also
11303 re-create them if needed (more on that later).
11305 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
11307 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
11308 @c large image, it's hard to scroll. Oh well.
11309 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
11311 The figure above shows the very beginning of the dependency graph of the
11312 distribution, corresponding to the package definitions of the @code{(gnu
11313 packages bootstrap)} module. A similar figure can be generated with
11314 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
11317 guix graph -t derivation \
11318 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
11322 At this level of detail, things are
11323 slightly complex. First, Guile itself consists of an ELF executable,
11324 along with many source and compiled Scheme files that are dynamically
11325 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
11326 tarball shown in this graph. This tarball is part of Guix's ``source''
11327 distribution, and gets inserted into the store with @code{add-to-store}
11328 (@pxref{The Store}).
11330 But how do we write a derivation that unpacks this tarball and adds it
11331 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
11332 derivation---the first one that gets built---uses @code{bash} as its
11333 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
11334 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
11335 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
11336 the Guix source distribution, whose sole purpose is to allow the Guile
11337 tarball to be unpacked.
11339 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
11340 Guile that can be used to run subsequent build programs. Its first task
11341 is to download tarballs containing the other pre-built binaries---this
11342 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
11343 @code{ftp-client.scm} are used for this purpose. The
11344 @code{module-import.drv} derivations import those modules in a directory
11345 in the store, using the original layout. The
11346 @code{module-import-compiled.drv} derivations compile those modules, and
11347 write them in an output directory with the right layout. This
11348 corresponds to the @code{#:modules} argument of
11349 @code{build-expression->derivation} (@pxref{Derivations}).
11351 Finally, the various tarballs are unpacked by the
11352 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
11353 etc., at which point we have a working C tool chain.
11356 @unnumberedsubsec Building the Build Tools
11358 Bootstrapping is complete when we have a full tool chain that does not
11359 depend on the pre-built bootstrap tools discussed above. This
11360 no-dependency requirement is verified by checking whether the files of
11361 the final tool chain contain references to the @file{/gnu/store}
11362 directories of the bootstrap inputs. The process that leads to this
11363 ``final'' tool chain is described by the package definitions found in
11364 the @code{(gnu packages commencement)} module.
11366 The @command{guix graph} command allows us to ``zoom out'' compared to
11367 the graph above, by looking at the level of package objects instead of
11368 individual derivations---remember that a package may translate to
11369 several derivations, typically one derivation to download its source,
11370 one to build the Guile modules it needs, and one to actually build the
11371 package from source. The command:
11374 guix graph -t bag \
11375 -e '(@@@@ (gnu packages commencement)
11376 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
11380 produces the dependency graph leading to the ``final'' C
11381 library@footnote{You may notice the @code{glibc-intermediate} label,
11382 suggesting that it is not @emph{quite} final, but as a good
11383 approximation, we will consider it final.}, depicted below.
11385 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
11387 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
11388 The first tool that gets built with the bootstrap binaries is
11389 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
11390 for all the following packages. From there Findutils and Diffutils get
11393 Then come the first-stage Binutils and GCC, built as pseudo cross
11394 tools---i.e., with @code{--target} equal to @code{--host}. They are
11395 used to build libc. Thanks to this cross-build trick, this libc is
11396 guaranteed not to hold any reference to the initial tool chain.
11398 From there the final Binutils and GCC (not shown above) are built.
11400 from the final Binutils, and links programs against the just-built libc.
11401 This tool chain is used to build the other packages used by Guix and by
11402 the GNU Build System: Guile, Bash, Coreutils, etc.
11404 And voilà! At this point we have the complete set of build tools that
11405 the GNU Build System expects. These are in the @code{%final-inputs}
11406 variable of the @code{(gnu packages commencement)} module, and are
11407 implicitly used by any package that uses @code{gnu-build-system}
11408 (@pxref{Build Systems, @code{gnu-build-system}}).
11411 @unnumberedsubsec Building the Bootstrap Binaries
11413 Because the final tool chain does not depend on the bootstrap binaries,
11414 those rarely need to be updated. Nevertheless, it is useful to have an
11415 automated way to produce them, should an update occur, and this is what
11416 the @code{(gnu packages make-bootstrap)} module provides.
11418 The following command builds the tarballs containing the bootstrap
11419 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
11420 of Coreutils and other basic command-line tools):
11423 guix build bootstrap-tarballs
11426 The generated tarballs are those that should be referred to in the
11427 @code{(gnu packages bootstrap)} module mentioned at the beginning of
11430 Still here? Then perhaps by now you've started to wonder: when do we
11431 reach a fixed point? That is an interesting question! The answer is
11432 unknown, but if you would like to investigate further (and have
11433 significant computational and storage resources to do so), then let us
11437 @section Porting to a New Platform
11439 As discussed above, the GNU distribution is self-contained, and
11440 self-containment is achieved by relying on pre-built ``bootstrap
11441 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
11442 operating system kernel, CPU architecture, and application binary
11443 interface (ABI). Thus, to port the distribution to a platform that is
11444 not yet supported, one must build those bootstrap binaries, and update
11445 the @code{(gnu packages bootstrap)} module to use them on that platform.
11447 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
11448 When everything goes well, and assuming the GNU tool chain supports the
11449 target platform, this can be as simple as running a command like this
11453 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
11456 For this to work, the @code{glibc-dynamic-linker} procedure in
11457 @code{(gnu packages bootstrap)} must be augmented to return the right
11458 file name for libc's dynamic linker on that platform; likewise,
11459 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
11460 taught about the new platform.
11462 Once these are built, the @code{(gnu packages bootstrap)} module needs
11463 to be updated to refer to these binaries on the target platform. That
11464 is, the hashes and URLs of the bootstrap tarballs for the new platform
11465 must be added alongside those of the currently supported platforms. The
11466 bootstrap Guile tarball is treated specially: it is expected to be
11467 available locally, and @file{gnu/local.mk} has rules do download it for
11468 the supported architectures; a rule for the new platform must be added
11471 In practice, there may be some complications. First, it may be that the
11472 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
11473 above) is not recognized by all the GNU tools. Typically, glibc
11474 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
11475 configure flag (see @code{gcc.scm} for examples of how to handle this).
11476 Second, some of the required packages could fail to build for that
11477 platform. Lastly, the generated binaries could be broken for some
11480 @c *********************************************************************
11481 @include contributing.texi
11483 @c *********************************************************************
11484 @node Acknowledgments
11485 @chapter Acknowledgments
11487 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
11488 which was designed and
11489 implemented by Eelco Dolstra, with contributions from other people (see
11490 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
11491 management, and promoted unprecedented features, such as transactional
11492 package upgrades and rollbacks, per-user profiles, and referentially
11493 transparent build processes. Without this work, Guix would not exist.
11495 The Nix-based software distributions, Nixpkgs and NixOS, have also been
11496 an inspiration for Guix.
11498 GNU@tie{}Guix itself is a collective work with contributions from a
11499 number of people. See the @file{AUTHORS} file in Guix for more
11500 information on these fine people. The @file{THANKS} file lists people
11501 who have helped by reporting bugs, taking care of the infrastructure,
11502 providing artwork and themes, making suggestions, and more---thank you!
11505 @c *********************************************************************
11506 @node GNU Free Documentation License
11507 @appendix GNU Free Documentation License
11509 @include fdl-1.3.texi
11511 @c *********************************************************************
11512 @node Concept Index
11513 @unnumbered Concept Index
11516 @node Programming Index
11517 @unnumbered Programming Index
11518 @syncodeindex tp fn
11519 @syncodeindex vr fn
11524 @c Local Variables:
11525 @c ispell-local-dictionary: "american";