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 * Scheduled Job Execution:: The mcron service.
208 * Networking Services:: Network setup, SSH daemon, etc.
209 * X Window:: Graphical display.
210 * Desktop Services:: D-Bus and desktop services.
211 * Database Services:: SQL databases.
212 * Mail Services:: IMAP, POP3, SMTP, and all that.
213 * Web Services:: Web servers.
214 * Various Services:: Other services.
218 * Service Composition:: The model for composing services.
219 * Service Types and Services:: Types and services.
220 * Service Reference:: API reference.
221 * Shepherd Services:: A particular type of service.
225 * Software Freedom:: What may go into the distribution.
226 * Package Naming:: What's in a name?
227 * Version Numbers:: When the name is not enough.
228 * Synopses and Descriptions:: Helping users find the right package.
229 * Python Modules:: Taming the snake.
230 * Perl Modules:: Little pearls.
231 * Java Packages:: Coffee break.
232 * Fonts:: Fond of fonts.
236 * Building from Git:: The latest and greatest.
237 * Running Guix Before It Is Installed:: Hacker tricks.
238 * The Perfect Setup:: The right tools.
239 * Coding Style:: Hygiene of the contributor.
240 * Submitting Patches:: Share your work.
244 * Programming Paradigm:: How to compose your elements.
245 * Modules:: Where to store your code?
246 * Data Types and Pattern Matching:: Implementing data structures.
247 * Formatting Code:: Writing conventions.
252 @c *********************************************************************
254 @chapter Introduction
257 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
258 using the international phonetic alphabet (IPA).} is a package
259 management tool for the GNU system. Guix makes it easy for unprivileged
260 users to install, upgrade, or remove packages, to roll back to a
261 previous package set, to build packages from source, and generally
262 assists with the creation and maintenance of software environments.
264 @cindex user interfaces
265 Guix provides a command-line package management interface
266 (@pxref{Invoking guix package}), a set of command-line utilities
267 (@pxref{Utilities}), a visual user interface in Emacs (@pxref{Emacs
268 Interface}), as well as Scheme programming interfaces
269 (@pxref{Programming Interface}).
271 Its @dfn{build daemon} is responsible for building packages on behalf of
272 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
273 binaries from authorized sources (@pxref{Substitutes}).
275 @cindex extensibility of the distribution
276 @cindex customization of packages
277 Guix includes package definitions for many GNU and non-GNU packages, all
278 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
279 user's computing freedom}. It is @emph{extensible}: users can write
280 their own package definitions (@pxref{Defining Packages}) and make them
281 available as independent package modules (@pxref{Package Modules}). It
282 is also @emph{customizable}: users can @emph{derive} specialized package
283 definitions from existing ones, including from the command line
284 (@pxref{Package Transformation Options}).
286 @cindex Guix System Distribution
288 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
289 where it complements the available tools without interference
290 (@pxref{Installation}), or you can use it as part of the standalone
291 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
292 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
293 system configuration and Guix takes care of instantiating the
294 configuration in a transactional, reproducible, and stateless fashion
295 (@pxref{System Configuration}).
297 @cindex functional package management
298 Under the hood, Guix implements the @dfn{functional package management}
299 discipline pioneered by Nix (@pxref{Acknowledgments}).
300 In Guix, the package build and installation process is seen
301 as a @emph{function}, in the mathematical sense. That function takes inputs,
302 such as build scripts, a compiler, and libraries, and
303 returns an installed package. As a pure function, its result depends
304 solely on its inputs---for instance, it cannot refer to software or
305 scripts that were not explicitly passed as inputs. A build function
306 always produces the same result when passed a given set of inputs. It
307 cannot alter the environment of the running system in
308 any way; for instance, it cannot create, modify, or delete files outside
309 of its build and installation directories. This is achieved by running
310 build processes in isolated environments (or @dfn{containers}), where only their
311 explicit inputs are visible.
314 The result of package build functions is @dfn{cached} in the file
315 system, in a special directory called @dfn{the store} (@pxref{The
316 Store}). Each package is installed in a directory of its own in the
317 store---by default under @file{/gnu/store}. The directory name contains
318 a hash of all the inputs used to build that package; thus, changing an
319 input yields a different directory name.
321 This approach is the foundation for the salient features of Guix: support
322 for transactional package upgrade and rollback, per-user installation, and
323 garbage collection of packages (@pxref{Features}).
326 @c *********************************************************************
328 @chapter Installation
330 GNU Guix is available for download from its website at
331 @url{http://www.gnu.org/software/guix/}. This section describes the
332 software requirements of Guix, as well as how to install it and get
335 Note that this section is concerned with the installation of the package
336 manager, which can be done on top of a running GNU/Linux system. If,
337 instead, you want to install the complete GNU operating system,
338 @pxref{System Installation}.
340 @cindex foreign distro
341 When installed on a running GNU/Linux system---thereafter called a
342 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
343 without interference. Its data lives exclusively in two directories,
344 usually @file{/gnu/store} and @file{/var/guix}; other files on your
345 system, such as @file{/etc}, are left untouched.
348 * Binary Installation:: Getting Guix running in no time!
349 * Requirements:: Software needed to build and run Guix.
350 * Running the Test Suite:: Testing Guix.
351 * Setting Up the Daemon:: Preparing the build daemon's environment.
352 * Invoking guix-daemon:: Running the build daemon.
353 * Application Setup:: Application-specific setup.
356 @node Binary Installation
357 @section Binary Installation
359 This section describes how to install Guix on an arbitrary system from a
360 self-contained tarball providing binaries for Guix and for all its
361 dependencies. This is often quicker than installing from source, which
362 is described in the next sections. The only requirement is to have
365 Installing goes along these lines:
369 Download the binary tarball from
370 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
371 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
372 already running the kernel Linux, and so on.
374 Make sure to download the associated @file{.sig} file and to verify the
375 authenticity of the tarball against it, along these lines:
378 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
379 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
382 If that command fails because you do not have the required public key,
383 then run this command to import it:
386 $ gpg --keyserver pgp.mit.edu --recv-keys 090B11993D9AEBB5
390 and rerun the @code{gpg --verify} command.
397 # tar --warning=no-timestamp -xf \
398 guix-binary-@value{VERSION}.@var{system}.tar.xz
399 # mv var/guix /var/ && mv gnu /
402 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
403 The latter contains a ready-to-use profile for @code{root} (see next
406 Do @emph{not} unpack the tarball on a working Guix system since that
407 would overwrite its own essential files.
409 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
410 not emit warnings about ``implausibly old time stamps'' (such
411 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
413 They stem from the fact that all the
414 files in the archive have their modification time set to zero (which
415 means January 1st, 1970.) This is done on purpose to make sure the
416 archive content is independent of its creation time, thus making it
420 Make @code{root}'s profile available under @file{~/.guix-profile}:
423 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
428 Create the group and user accounts for build users as explained below
429 (@pxref{Build Environment Setup}).
432 Run the daemon, and set it to automatically start on boot.
434 If your host distro uses the systemd init system, this can be achieved
438 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
440 # systemctl start guix-daemon && systemctl enable guix-daemon
443 If your host distro uses the Upstart init system:
446 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
450 Otherwise, you can still start the daemon manually with:
453 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
457 Make the @command{guix} command available to other users on the machine,
461 # mkdir -p /usr/local/bin
463 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
466 It is also a good idea to make the Info version of this manual available
470 # mkdir -p /usr/local/share/info
471 # cd /usr/local/share/info
472 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
476 That way, assuming @file{/usr/local/share/info} is in the search path,
477 running @command{info guix} will open this manual (@pxref{Other Info
478 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
482 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
483 (@pxref{Substitutes}), authorize them:
486 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
490 This completes root-level install of Guix. Each user will need to
491 perform additional steps to make their Guix envionment ready for use,
492 @pxref{Application Setup}.
494 You can confirm that Guix is working by installing a sample package into
498 # guix package -i hello
501 The @code{guix} package must remain available in @code{root}'s profile,
502 or it would become subject to garbage collection---in which case you
503 would find yourself badly handicapped by the lack of the @command{guix}
504 command. In other words, do not remove @code{guix} by running
505 @code{guix package -r guix}.
507 The binary installation tarball can be (re)produced and verified simply
508 by running the following command in the Guix source tree:
511 make guix-binary.@var{system}.tar.xz
516 @section Requirements
518 This section lists requirements when building Guix from source. The
519 build procedure for Guix is the same as for other GNU software, and is
520 not covered here. Please see the files @file{README} and @file{INSTALL}
521 in the Guix source tree for additional details.
523 GNU Guix depends on the following packages:
526 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.7 or later;
527 @item @url{http://gnupg.org/, GNU libgcrypt};
528 @item @url{http://www.gnu.org/software/make/, GNU Make}.
531 The following dependencies are optional:
535 Installing @uref{http://gnutls.org/, GnuTLS-Guile} will allow you to
536 access @code{https} URLs for substitutes, which is highly recommended
537 (@pxref{Substitutes}). It also allows you to access HTTPS URLs with the
538 @command{guix download} command (@pxref{Invoking guix download}), the
539 @command{guix import pypi} command, and the @command{guix import cpan}
540 command. @xref{Guile Preparations, how to install the GnuTLS bindings
541 for Guile,, gnutls-guile, GnuTLS-Guile}.
545 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
546 allow you to use the @command{guix import pypi} command (@pxref{Invoking
547 guix import}). It is of
548 interest primarily for developers and not for casual users.
551 Unless @code{--disable-daemon} was passed to @command{configure}, the
552 following packages are also needed:
555 @item @url{http://sqlite.org, SQLite 3};
556 @item @url{http://www.bzip.org, libbz2};
557 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
561 When configuring Guix on a system that already has a Guix installation,
562 be sure to specify the same state directory as the existing installation
563 using the @code{--localstatedir} option of the @command{configure}
564 script (@pxref{Directory Variables, @code{localstatedir},, standards,
565 GNU Coding Standards}). The @command{configure} script protects against
566 unintended misconfiguration of @var{localstatedir} so you do not
567 inadvertently corrupt your store (@pxref{The Store}).
569 When a working installation of @url{http://nixos.org/nix/, the Nix package
570 manager} is available, you
571 can instead configure Guix with @code{--disable-daemon}. In that case,
572 Nix replaces the three dependencies above.
574 Guix is compatible with Nix, so it is possible to share the same store
575 between both. To do so, you must pass @command{configure} not only the
576 same @code{--with-store-dir} value, but also the same
577 @code{--localstatedir} value. The latter is essential because it
578 specifies where the database that stores metadata about the store is
579 located, among other things. The default values for Nix are
580 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
581 Note that @code{--disable-daemon} is not required if
582 your goal is to share the store with Nix.
584 @node Running the Test Suite
585 @section Running the Test Suite
587 After a successful @command{configure} and @code{make} run, it is a good
588 idea to run the test suite. It can help catch issues with the setup or
589 environment, or bugs in Guix itself---and really, reporting test
590 failures is a good way to help improve the software. To run the test
597 Test cases can run in parallel: you can use the @code{-j} option of
598 GNU@tie{}make to speed things up. The first run may take a few minutes
599 on a recent machine; subsequent runs will be faster because the store
600 that is created for test purposes will already have various things in
603 It is also possible to run a subset of the tests by defining the
604 @code{TESTS} makefile variable as in this example:
607 make check TESTS="tests/store.scm tests/cpio.scm"
610 By default, tests results are displayed at a file level. In order to
611 see the details of every individual test cases, it is possible to define
612 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
615 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
618 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
619 @file{test-suite.log} file. Please specify the Guix version being used
620 as well as version numbers of the dependencies (@pxref{Requirements}) in
623 Guix also comes with a whole-system test suite that tests complete
624 GuixSD operating system instances. It can only run on systems where
625 Guix is already installed, using:
632 or, again, by defining @code{TESTS} to select a subset of tests to run:
635 make check-system TESTS="basic mcron"
638 These system tests are defined in the @code{(gnu tests @dots{})}
639 modules. They work by running the operating systems under test with
640 lightweight instrumentation in a virtual machine (VM). They can be
641 computationally intensive or rather cheap, depending on whether
642 substitutes are available for their dependencies (@pxref{Substitutes}).
643 Some of them require a lot of storage space to hold VM images.
645 Again in case of test failures, please send @email{bug-guix@@gnu.org}
648 @node Setting Up the Daemon
649 @section Setting Up the Daemon
652 Operations such as building a package or running the garbage collector
653 are all performed by a specialized process, the @dfn{build daemon}, on
654 behalf of clients. Only the daemon may access the store and its
655 associated database. Thus, any operation that manipulates the store
656 goes through the daemon. For instance, command-line tools such as
657 @command{guix package} and @command{guix build} communicate with the
658 daemon (@i{via} remote procedure calls) to instruct it what to do.
660 The following sections explain how to prepare the build daemon's
661 environment. See also @ref{Substitutes}, for information on how to allow
662 the daemon to download pre-built binaries.
665 * Build Environment Setup:: Preparing the isolated build environment.
666 * Daemon Offload Setup:: Offloading builds to remote machines.
669 @node Build Environment Setup
670 @subsection Build Environment Setup
672 In a standard multi-user setup, Guix and its daemon---the
673 @command{guix-daemon} program---are installed by the system
674 administrator; @file{/gnu/store} is owned by @code{root} and
675 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
676 Guix tools to build packages or otherwise access the store, and the
677 daemon will do it on their behalf, ensuring that the store is kept in a
678 consistent state, and allowing built packages to be shared among users.
681 When @command{guix-daemon} runs as @code{root}, you may not want package
682 build processes themselves to run as @code{root} too, for obvious
683 security reasons. To avoid that, a special pool of @dfn{build users}
684 should be created for use by build processes started by the daemon.
685 These build users need not have a shell and a home directory: they will
686 just be used when the daemon drops @code{root} privileges in build
687 processes. Having several such users allows the daemon to launch
688 distinct build processes under separate UIDs, which guarantees that they
689 do not interfere with each other---an essential feature since builds are
690 regarded as pure functions (@pxref{Introduction}).
692 On a GNU/Linux system, a build user pool may be created like this (using
693 Bash syntax and the @code{shadow} commands):
695 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
696 @c for why `-G' is needed.
698 # groupadd --system guixbuild
699 # for i in `seq -w 1 10`;
701 useradd -g guixbuild -G guixbuild \
702 -d /var/empty -s `which nologin` \
703 -c "Guix build user $i" --system \
709 The number of build users determines how many build jobs may run in
710 parallel, as specified by the @option{--max-jobs} option
711 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
712 @command{guix system vm} and related commands, you may need to add the
713 build users to the @code{kvm} group so they can access @file{/dev/kvm},
714 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
715 (@pxref{Invoking guix system}).
717 The @code{guix-daemon} program may then be run as @code{root} with the
718 following command@footnote{If your machine uses the systemd init system,
719 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
720 file in @file{/etc/systemd/system} will ensure that
721 @command{guix-daemon} is automatically started. Similarly, if your
722 machine uses the Upstart init system, drop the
723 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
724 file in @file{/etc/init}.}:
727 # guix-daemon --build-users-group=guixbuild
732 This way, the daemon starts build processes in a chroot, under one of
733 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
734 environment contains nothing but:
736 @c Keep this list in sync with libstore/build.cc! -----------------------
739 a minimal @code{/dev} directory, created mostly independently from the
740 host @code{/dev}@footnote{``Mostly'', because while the set of files
741 that appear in the chroot's @code{/dev} is fixed, most of these files
742 can only be created if the host has them.};
745 the @code{/proc} directory; it only shows the processes of the container
746 since a separate PID name space is used;
749 @file{/etc/passwd} with an entry for the current user and an entry for
753 @file{/etc/group} with an entry for the user's group;
756 @file{/etc/hosts} with an entry that maps @code{localhost} to
760 a writable @file{/tmp} directory.
763 You can influence the directory where the daemon stores build trees
764 @i{via} the @code{TMPDIR} environment variable. However, the build tree
765 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
766 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
767 This way, the value of @code{TMPDIR} does not leak inside build
768 environments, which avoids discrepancies in cases where build processes
769 capture the name of their build tree.
772 The daemon also honors the @code{http_proxy} environment variable for
773 HTTP downloads it performs, be it for fixed-output derivations
774 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
776 If you are installing Guix as an unprivileged user, it is still possible
777 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
778 However, build processes will not be isolated from one another, and not
779 from the rest of the system. Thus, build processes may interfere with
780 each other, and may access programs, libraries, and other files
781 available on the system---making it much harder to view them as
782 @emph{pure} functions.
785 @node Daemon Offload Setup
786 @subsection Using the Offload Facility
790 When desired, the build daemon can @dfn{offload}
791 derivation builds to other machines
792 running Guix, using the @code{offload} @dfn{build hook}. When that
793 feature is enabled, a list of user-specified build machines is read from
794 @file{/etc/guix/machines.scm}; every time a build is requested, for
795 instance via @code{guix build}, the daemon attempts to offload it to one
796 of the machines that satisfy the constraints of the derivation, in
797 particular its system type---e.g., @file{x86_64-linux}. Missing
798 prerequisites for the build are copied over SSH to the target machine,
799 which then proceeds with the build; upon success the output(s) of the
800 build are copied back to the initial machine.
802 The @file{/etc/guix/machines.scm} file typically looks like this:
806 (name "eightysix.example.org")
807 (system "x86_64-linux")
809 (speed 2.)) ; incredibly fast!
812 (name "meeps.example.org")
813 (system "mips64el-linux")
816 (string-append (getenv "HOME")
817 "/.lsh/identity-for-guix"))))
821 In the example above we specify a list of two build machines, one for
822 the @code{x86_64} architecture and one for the @code{mips64el}
825 In fact, this file is---not surprisingly!---a Scheme file that is
826 evaluated when the @code{offload} hook is started. Its return value
827 must be a list of @code{build-machine} objects. While this example
828 shows a fixed list of build machines, one could imagine, say, using
829 DNS-SD to return a list of potential build machines discovered in the
830 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
831 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
834 @deftp {Data Type} build-machine
835 This data type represents build machines to which the daemon may offload
836 builds. The important fields are:
841 The host name of the remote machine.
844 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
847 The user account to use when connecting to the remote machine over SSH.
848 Note that the SSH key pair must @emph{not} be passphrase-protected, to
849 allow non-interactive logins.
853 A number of optional fields may be specified:
858 Port number of SSH server on the machine (default: 22).
861 The SSH private key file to use when connecting to the machine.
863 Currently offloading uses GNU@tie{}lsh as its SSH client
864 (@pxref{Invoking lsh,,, GNU lsh Manual}). Thus, the key file here must
865 be an lsh key file. This may change in the future, though.
867 @item parallel-builds
868 The number of builds that may run in parallel on the machine (1 by
872 A ``relative speed factor''. The offload scheduler will tend to prefer
873 machines with a higher speed factor.
876 A list of strings denoting specific features supported by the machine.
877 An example is @code{"kvm"} for machines that have the KVM Linux modules
878 and corresponding hardware support. Derivations can request features by
879 name, and they will be scheduled on matching build machines.
884 The @code{guix} command must be in the search path on the build
885 machines, since offloading works by invoking the @code{guix archive} and
886 @code{guix build} commands. In addition, the Guix modules must be in
887 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
888 this is the case by running:
891 lsh build-machine guile -c "'(use-modules (guix config))'"
894 There is one last thing to do once @file{machines.scm} is in place. As
895 explained above, when offloading, files are transferred back and forth
896 between the machine stores. For this to work, you first need to
897 generate a key pair on each machine to allow the daemon to export signed
898 archives of files from the store (@pxref{Invoking guix archive}):
901 # guix archive --generate-key
905 Each build machine must authorize the key of the master machine so that
906 it accepts store items it receives from the master:
909 # guix archive --authorize < master-public-key.txt
913 Likewise, the master machine must authorize the key of each build machine.
915 All the fuss with keys is here to express pairwise mutual trust
916 relations between the master and the build machines. Concretely, when
917 the master receives files from a build machine (and @i{vice versa}), its
918 build daemon can make sure they are genuine, have not been tampered
919 with, and that they are signed by an authorized key.
922 @node Invoking guix-daemon
923 @section Invoking @command{guix-daemon}
925 The @command{guix-daemon} program implements all the functionality to
926 access the store. This includes launching build processes, running the
927 garbage collector, querying the availability of a build result, etc. It
928 is normally run as @code{root} like this:
931 # guix-daemon --build-users-group=guixbuild
935 For details on how to set it up, @pxref{Setting Up the Daemon}.
938 @cindex container, build environment
939 @cindex build environment
940 @cindex reproducible builds
941 By default, @command{guix-daemon} launches build processes under
942 different UIDs, taken from the build group specified with
943 @code{--build-users-group}. In addition, each build process is run in a
944 chroot environment that only contains the subset of the store that the
945 build process depends on, as specified by its derivation
946 (@pxref{Programming Interface, derivation}), plus a set of specific
947 system directories. By default, the latter contains @file{/dev} and
948 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
949 @dfn{container}: in addition to having its own file system tree, it has
950 a separate mount name space, its own PID name space, network name space,
951 etc. This helps achieve reproducible builds (@pxref{Features}).
953 When the daemon performs a build on behalf of the user, it creates a
954 build directory under @file{/tmp} or under the directory specified by
955 its @code{TMPDIR} environment variable; this directory is shared with
956 the container for the duration of the build. Be aware that using a
957 directory other than @file{/tmp} can affect build results---for example,
958 with a longer directory name, a build process that uses Unix-domain
959 sockets might hit the name length limitation for @code{sun_path}, which
960 it would otherwise not hit.
962 The build directory is automatically deleted upon completion, unless the
963 build failed and the client specified @option{--keep-failed}
964 (@pxref{Invoking guix build, @option{--keep-failed}}).
966 The following command-line options are supported:
969 @item --build-users-group=@var{group}
970 Take users from @var{group} to run build processes (@pxref{Setting Up
971 the Daemon, build users}).
973 @item --no-substitutes
975 Do not use substitutes for build products. That is, always build things
976 locally instead of allowing downloads of pre-built binaries
977 (@pxref{Substitutes}).
979 By default substitutes are used, unless the client---such as the
980 @command{guix package} command---is explicitly invoked with
981 @code{--no-substitutes}.
983 When the daemon runs with @code{--no-substitutes}, clients can still
984 explicitly enable substitution @i{via} the @code{set-build-options}
985 remote procedure call (@pxref{The Store}).
987 @item --substitute-urls=@var{urls}
988 @anchor{daemon-substitute-urls}
989 Consider @var{urls} the default whitespace-separated list of substitute
990 source URLs. When this option is omitted,
991 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
992 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
994 This means that substitutes may be downloaded from @var{urls}, as long
995 as they are signed by a trusted signature (@pxref{Substitutes}).
998 @item --no-build-hook
999 Do not use the @dfn{build hook}.
1001 The build hook is a helper program that the daemon can start and to
1002 which it submits build requests. This mechanism is used to offload
1003 builds to other machines (@pxref{Daemon Offload Setup}).
1005 @item --cache-failures
1006 Cache build failures. By default, only successful builds are cached.
1008 When this option is used, @command{guix gc --list-failures} can be used
1009 to query the set of store items marked as failed; @command{guix gc
1010 --clear-failures} removes store items from the set of cached failures.
1011 @xref{Invoking guix gc}.
1013 @item --cores=@var{n}
1015 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1018 The default value is @code{0}, but it may be overridden by clients, such
1019 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1022 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1023 in the build process, which can then use it to exploit internal
1024 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1026 @item --max-jobs=@var{n}
1028 Allow at most @var{n} build jobs in parallel. The default value is
1029 @code{1}. Setting it to @code{0} means that no builds will be performed
1030 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1031 Setup}), or simply fail.
1033 @item --rounds=@var{N}
1034 Build each derivation @var{n} times in a row, and raise an error if
1035 consecutive build results are not bit-for-bit identical. Note that this
1036 setting can be overridden by clients such as @command{guix build}
1037 (@pxref{Invoking guix build}).
1039 When used in conjunction with @option{--keep-failed}, the differing
1040 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1041 This makes it easy to look for differences between the two results.
1044 Produce debugging output.
1046 This is useful to debug daemon start-up issues, but then it may be
1047 overridden by clients, for example the @code{--verbosity} option of
1048 @command{guix build} (@pxref{Invoking guix build}).
1050 @item --chroot-directory=@var{dir}
1051 Add @var{dir} to the build chroot.
1053 Doing this may change the result of build processes---for instance if
1054 they use optional dependencies found in @var{dir} when it is available,
1055 and not otherwise. For that reason, it is not recommended to do so.
1056 Instead, make sure that each derivation declares all the inputs that it
1059 @item --disable-chroot
1060 Disable chroot builds.
1062 Using this option is not recommended since, again, it would allow build
1063 processes to gain access to undeclared dependencies. It is necessary,
1064 though, when @command{guix-daemon} is running under an unprivileged user
1067 @item --disable-log-compression
1068 Disable compression of the build logs.
1070 Unless @code{--lose-logs} is used, all the build logs are kept in the
1071 @var{localstatedir}. To save space, the daemon automatically compresses
1072 them with bzip2 by default. This option disables that.
1074 @item --disable-deduplication
1075 @cindex deduplication
1076 Disable automatic file ``deduplication'' in the store.
1078 By default, files added to the store are automatically ``deduplicated'':
1079 if a newly added file is identical to another one found in the store,
1080 the daemon makes the new file a hard link to the other file. This can
1081 noticeably reduce disk usage, at the expense of slightly increased
1082 input/output load at the end of a build process. This option disables
1085 @item --gc-keep-outputs[=yes|no]
1086 Tell whether the garbage collector (GC) must keep outputs of live
1089 When set to ``yes'', the GC will keep the outputs of any live derivation
1090 available in the store---the @code{.drv} files. The default is ``no'',
1091 meaning that derivation outputs are kept only if they are GC roots.
1093 @item --gc-keep-derivations[=yes|no]
1094 Tell whether the garbage collector (GC) must keep derivations
1095 corresponding to live outputs.
1097 When set to ``yes'', as is the case by default, the GC keeps
1098 derivations---i.e., @code{.drv} files---as long as at least one of their
1099 outputs is live. This allows users to keep track of the origins of
1100 items in their store. Setting it to ``no'' saves a bit of disk space.
1102 Note that when both @code{--gc-keep-derivations} and
1103 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1104 prerequisites (the sources, compiler, libraries, and other build-time
1105 tools) of live objects in the store, regardless of whether these
1106 prerequisites are live. This is convenient for developers since it
1107 saves rebuilds or downloads.
1109 @item --impersonate-linux-2.6
1110 On Linux-based systems, impersonate Linux 2.6. This means that the
1111 kernel's @code{uname} system call will report 2.6 as the release number.
1113 This might be helpful to build programs that (usually wrongfully) depend
1114 on the kernel version number.
1117 Do not keep build logs. By default they are kept under
1118 @code{@var{localstatedir}/guix/log}.
1120 @item --system=@var{system}
1121 Assume @var{system} as the current system type. By default it is the
1122 architecture/kernel pair found at configure time, such as
1123 @code{x86_64-linux}.
1125 @item --listen=@var{socket}
1126 Listen for connections on @var{socket}, the file name of a Unix-domain
1127 socket. The default socket is
1128 @file{@var{localstatedir}/daemon-socket/socket}. This option is only
1129 useful in exceptional circumstances, such as if you need to run several
1130 daemons on the same machine.
1134 @node Application Setup
1135 @section Application Setup
1137 @cindex foreign distro
1138 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1139 so-called @dfn{foreign distro}---a few additional steps are needed to
1140 get everything in place. Here are some of them.
1144 @anchor{locales-and-locpath}
1145 @cindex locales, when not on GuixSD
1147 @vindex GUIX_LOCPATH
1148 Packages installed @i{via} Guix will not use the locale data of the
1149 host system. Instead, you must first install one of the locale packages
1150 available with Guix and then define the @code{GUIX_LOCPATH} environment
1154 $ guix package -i glibc-locales
1155 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1158 Note that the @code{glibc-locales} package contains data for all the
1159 locales supported by the GNU@tie{}libc and weighs in at around
1160 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1161 limited to a few UTF-8 locales.
1163 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1164 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1165 Manual}). There are two important differences though:
1169 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1170 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1171 to make sure the programs of the foreign distro will not end up loading
1172 incompatible locale data.
1175 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1176 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1177 should your Guix profile contain a mixture of programs linked against
1178 different libc version, each libc version will only try to load locale
1179 data in the right format.
1182 This is important because the locale data format used by different libc
1183 versions may be incompatible.
1185 @subsection X11 Fonts
1187 The majority of graphical applications use Fontconfig to locate and
1188 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1189 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1190 by default. Thus, to allow graphical applications installed with Guix
1191 to display fonts, you have to install fonts with Guix as well.
1192 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1193 @code{font-gnu-freefont-ttf}.
1195 To display text written in Chinese languages, Japanese, or Korean in
1196 graphical applications, consider installing
1197 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1198 has multiple outputs, one per language family (@pxref{Packages with
1199 Multiple Outputs}). For instance, the following command installs fonts
1200 for Chinese languages:
1203 guix package -i font-adobe-source-han-sans:cn
1206 @subsection X.509 Certificates
1208 The @code{nss-certs} package provides X.509 certificates, which allow
1209 programs to authenticate Web servers accessed over HTTPS.
1211 When using Guix on a foreign distro, you can install this package and
1212 define the relevant environment variables so that packages know where to
1213 look for certificates. @pxref{X.509 Certificates}, for detailed
1216 @subsection Emacs Packages
1218 When you install Emacs packages with Guix, the elisp files may be placed
1219 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1221 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1222 directory exists because potentially there may exist thousands of Emacs
1223 packages and storing all their files in a single directory may be not
1224 reliable (because of name conflicts). So we think using a separate
1225 directory for each package is a good idea. It is very similar to how
1226 the Emacs package system organizes the file structure (@pxref{Package
1227 Files,,, emacs, The GNU Emacs Manual}).
1229 By default, Emacs (installed with Guix) ``knows'' where these packages
1230 are placed, so you do not need to perform any configuration. If, for
1231 some reason, you want to avoid auto-loading Emacs packages installed
1232 with Guix, you can do so by running Emacs with @code{--no-site-file}
1233 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1237 @c *********************************************************************
1238 @node Package Management
1239 @chapter Package Management
1241 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1242 remove software packages, without having to know about their build
1243 procedures or dependencies. Guix also goes beyond this obvious set of
1246 This chapter describes the main features of Guix, as well as the package
1247 management tools it provides. Two user interfaces are provided for
1248 routine package management tasks: A command-line interface described below
1249 (@pxref{Invoking guix package, @code{guix package}}), as well as a visual user
1250 interface in Emacs described in a subsequent chapter (@pxref{Emacs Interface}).
1253 * Features:: How Guix will make your life brighter.
1254 * Invoking guix package:: Package installation, removal, etc.
1255 * Substitutes:: Downloading pre-built binaries.
1256 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1257 * Invoking guix gc:: Running the garbage collector.
1258 * Invoking guix pull:: Fetching the latest Guix and distribution.
1259 * Invoking guix archive:: Exporting and importing store files.
1265 When using Guix, each package ends up in the @dfn{package store}, in its
1266 own directory---something that resembles
1267 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string
1268 (note that Guix comes with an Emacs extension to shorten those file
1269 names, @pxref{Emacs Prettify}.)
1271 Instead of referring to these directories, users have their own
1272 @dfn{profile}, which points to the packages that they actually want to
1273 use. These profiles are stored within each user's home directory, at
1274 @code{$HOME/.guix-profile}.
1276 For example, @code{alice} installs GCC 4.7.2. As a result,
1277 @file{/home/alice/.guix-profile/bin/gcc} points to
1278 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1279 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1280 simply continues to point to
1281 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1282 coexist on the same system without any interference.
1284 The @command{guix package} command is the central tool to manage
1285 packages (@pxref{Invoking guix package}). It operates on the per-user
1286 profiles, and can be used @emph{with normal user privileges}.
1288 The command provides the obvious install, remove, and upgrade
1289 operations. Each invocation is actually a @emph{transaction}: either
1290 the specified operation succeeds, or nothing happens. Thus, if the
1291 @command{guix package} process is terminated during the transaction,
1292 or if a power outage occurs during the transaction, then the user's
1293 profile remains in its previous state, and remains usable.
1295 In addition, any package transaction may be @emph{rolled back}. So, if,
1296 for example, an upgrade installs a new version of a package that turns
1297 out to have a serious bug, users may roll back to the previous instance
1298 of their profile, which was known to work well. Similarly, the global
1299 system configuration on GuixSD is subject to
1300 transactional upgrades and roll-back
1301 (@pxref{Using the Configuration System}).
1303 All packages in the package store may be @emph{garbage-collected}.
1304 Guix can determine which packages are still referenced by user
1305 profiles, and remove those that are provably no longer referenced
1306 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1307 generations of their profile so that the packages they refer to can be
1310 @cindex reproducibility
1311 @cindex reproducible builds
1312 Finally, Guix takes a @dfn{purely functional} approach to package
1313 management, as described in the introduction (@pxref{Introduction}).
1314 Each @file{/gnu/store} package directory name contains a hash of all the
1315 inputs that were used to build that package---compiler, libraries, build
1316 scripts, etc. This direct correspondence allows users to make sure a
1317 given package installation matches the current state of their
1318 distribution. It also helps maximize @dfn{build reproducibility}:
1319 thanks to the isolated build environments that are used, a given build
1320 is likely to yield bit-identical files when performed on different
1321 machines (@pxref{Invoking guix-daemon, container}).
1324 This foundation allows Guix to support @dfn{transparent binary/source
1325 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1326 available from an external source---a @dfn{substitute}, Guix just
1327 downloads it and unpacks it;
1328 otherwise, it builds the package from source, locally
1329 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1330 reproducible, users do not have to trust servers that provide
1331 substitutes: they can force a local build and @emph{challenge} providers
1332 (@pxref{Invoking guix challenge}).
1334 Control over the build environment is a feature that is also useful for
1335 developers. The @command{guix environment} command allows developers of
1336 a package to quickly set up the right development environment for their
1337 package, without having to manually install the dependencies of the
1338 package into their profile (@pxref{Invoking guix environment}).
1340 @node Invoking guix package
1341 @section Invoking @command{guix package}
1343 The @command{guix package} command is the tool that allows users to
1344 install, upgrade, and remove packages, as well as rolling back to
1345 previous configurations. It operates only on the user's own profile,
1346 and works with normal user privileges (@pxref{Features}). Its syntax
1350 guix package @var{options}
1353 Primarily, @var{options} specifies the operations to be performed during
1354 the transaction. Upon completion, a new profile is created, but
1355 previous @dfn{generations} of the profile remain available, should the user
1358 For example, to remove @code{lua} and install @code{guile} and
1359 @code{guile-cairo} in a single transaction:
1362 guix package -r lua -i guile guile-cairo
1365 @command{guix package} also supports a @dfn{declarative approach}
1366 whereby the user specifies the exact set of packages to be available and
1367 passes it @i{via} the @option{--manifest} option
1368 (@pxref{profile-manifest, @option{--manifest}}).
1370 For each user, a symlink to the user's default profile is automatically
1371 created in @file{$HOME/.guix-profile}. This symlink always points to the
1372 current generation of the user's default profile. Thus, users can add
1373 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1374 variable, and so on.
1375 @cindex search paths
1376 If you are not using the Guix System Distribution, consider adding the
1377 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1378 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1379 shells get all the right environment variable definitions:
1382 GUIX_PROFILE="$HOME/.guix-profile" \
1383 source "$HOME/.guix-profile/etc/profile"
1386 In a multi-user setup, user profiles are stored in a place registered as
1387 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1388 to (@pxref{Invoking guix gc}). That directory is normally
1389 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1390 @var{localstatedir} is the value passed to @code{configure} as
1391 @code{--localstatedir}, and @var{user} is the user name. The
1392 @file{per-user} directory is created when @command{guix-daemon} is
1393 started, and the @var{user} sub-directory is created by @command{guix
1396 The @var{options} can be among the following:
1400 @item --install=@var{package} @dots{}
1401 @itemx -i @var{package} @dots{}
1402 Install the specified @var{package}s.
1404 Each @var{package} may specify either a simple package name, such as
1405 @code{guile}, or a package name followed by an at-sign and version number,
1406 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1407 case, the newest version prefixed by @code{1.8} is selected.)
1409 If no version number is specified, the
1410 newest available version will be selected. In addition, @var{package}
1411 may contain a colon, followed by the name of one of the outputs of the
1412 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1413 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1414 name (and optionally version) are searched for among the GNU
1415 distribution modules (@pxref{Package Modules}).
1417 @cindex propagated inputs
1418 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1419 that automatically get installed along with the required package
1420 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1421 @code{package} objects}, for information about propagated inputs in
1422 package definitions).
1424 @anchor{package-cmd-propagated-inputs}
1425 An example is the GNU MPC library: its C header files refer to those of
1426 the GNU MPFR library, which in turn refer to those of the GMP library.
1427 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1428 in the profile; removing MPC also removes MPFR and GMP---unless they had
1429 also been explicitly installed by the user.
1431 Besides, packages sometimes rely on the definition of environment
1432 variables for their search paths (see explanation of
1433 @code{--search-paths} below). Any missing or possibly incorrect
1434 environment variable definitions are reported here.
1436 @item --install-from-expression=@var{exp}
1438 Install the package @var{exp} evaluates to.
1440 @var{exp} must be a Scheme expression that evaluates to a
1441 @code{<package>} object. This option is notably useful to disambiguate
1442 between same-named variants of a package, with expressions such as
1443 @code{(@@ (gnu packages base) guile-final)}.
1445 Note that this option installs the first output of the specified
1446 package, which may be insufficient when needing a specific output of a
1447 multiple-output package.
1449 @item --install-from-file=@var{file}
1450 @itemx -f @var{file}
1451 Install the package that the code within @var{file} evaluates to.
1453 As an example, @var{file} might contain a definition like this
1454 (@pxref{Defining Packages}):
1457 @verbatiminclude package-hello.scm
1460 Developers may find it useful to include such a @file{guix.scm} file
1461 in the root of their project source tree that can be used to test
1462 development snapshots and create reproducible development environments
1463 (@pxref{Invoking guix environment}).
1465 @item --remove=@var{package} @dots{}
1466 @itemx -r @var{package} @dots{}
1467 Remove the specified @var{package}s.
1469 As for @code{--install}, each @var{package} may specify a version number
1470 and/or output name in addition to the package name. For instance,
1471 @code{-r glibc:debug} would remove the @code{debug} output of
1474 @item --upgrade[=@var{regexp} @dots{}]
1475 @itemx -u [@var{regexp} @dots{}]
1476 Upgrade all the installed packages. If one or more @var{regexp}s are
1477 specified, upgrade only installed packages whose name matches a
1478 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1480 Note that this upgrades package to the latest version of packages found
1481 in the distribution currently installed. To update your distribution,
1482 you should regularly run @command{guix pull} (@pxref{Invoking guix
1485 @item --do-not-upgrade[=@var{regexp} @dots{}]
1486 When used together with the @code{--upgrade} option, do @emph{not}
1487 upgrade any packages whose name matches a @var{regexp}. For example, to
1488 upgrade all packages in the current profile except those containing the
1489 substring ``emacs'':
1492 $ guix package --upgrade . --do-not-upgrade emacs
1495 @item @anchor{profile-manifest}--manifest=@var{file}
1496 @itemx -m @var{file}
1497 @cindex profile declaration
1498 @cindex profile manifest
1499 Create a new generation of the profile from the manifest object
1500 returned by the Scheme code in @var{file}.
1502 This allows you to @emph{declare} the profile's contents rather than
1503 constructing it through a sequence of @code{--install} and similar
1504 commands. The advantage is that @var{file} can be put under version
1505 control, copied to different machines to reproduce the same profile, and
1508 @c FIXME: Add reference to (guix profile) documentation when available.
1509 @var{file} must return a @dfn{manifest} object, which is roughly a list
1512 @findex packages->manifest
1514 (use-package-modules guile emacs)
1519 ;; Use a specific package output.
1520 (list guile-2.0 "debug")))
1524 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1525 the last transaction.
1527 When combined with options such as @code{--install}, roll back occurs
1528 before any other actions.
1530 When rolling back from the first generation that actually contains
1531 installed packages, the profile is made to point to the @dfn{zeroth
1532 generation}, which contains no files apart from its own metadata.
1534 After having rolled back, installing, removing, or upgrading packages
1535 overwrites previous future generations. Thus, the history of the
1536 generations in a profile is always linear.
1538 @item --switch-generation=@var{pattern}
1539 @itemx -S @var{pattern}
1540 Switch to a particular generation defined by @var{pattern}.
1542 @var{pattern} may be either a generation number or a number prefixed
1543 with ``+'' or ``-''. The latter means: move forward/backward by a
1544 specified number of generations. For example, if you want to return to
1545 the latest generation after @code{--roll-back}, use
1546 @code{--switch-generation=+1}.
1548 The difference between @code{--roll-back} and
1549 @code{--switch-generation=-1} is that @code{--switch-generation} will
1550 not make a zeroth generation, so if a specified generation does not
1551 exist, the current generation will not be changed.
1553 @item --search-paths[=@var{kind}]
1554 @cindex search paths
1555 Report environment variable definitions, in Bash syntax, that may be
1556 needed in order to use the set of installed packages. These environment
1557 variables are used to specify @dfn{search paths} for files used by some
1558 of the installed packages.
1560 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1561 environment variables to be defined so it can look for headers and
1562 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1563 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1564 library are installed in the profile, then @code{--search-paths} will
1565 suggest setting these variables to @code{@var{profile}/include} and
1566 @code{@var{profile}/lib}, respectively.
1568 The typical use case is to define these environment variables in the
1572 $ eval `guix package --search-paths`
1575 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1576 meaning that the returned environment variable definitions will either
1577 be exact settings, or prefixes or suffixes of the current value of these
1578 variables. When omitted, @var{kind} defaults to @code{exact}.
1580 This option can also be used to compute the @emph{combined} search paths
1581 of several profiles. Consider this example:
1584 $ guix package -p foo -i guile
1585 $ guix package -p bar -i guile-json
1586 $ guix package -p foo -p bar --search-paths
1589 The last command above reports about the @code{GUILE_LOAD_PATH}
1590 variable, even though, taken individually, neither @file{foo} nor
1591 @file{bar} would lead to that recommendation.
1594 @item --profile=@var{profile}
1595 @itemx -p @var{profile}
1596 Use @var{profile} instead of the user's default profile.
1599 Produce verbose output. In particular, emit the build log of the
1600 environment on the standard error port.
1603 Use the bootstrap Guile to build the profile. This option is only
1604 useful to distribution developers.
1608 In addition to these actions, @command{guix package} supports the
1609 following options to query the current state of a profile, or the
1610 availability of packages:
1614 @item --search=@var{regexp}
1615 @itemx -s @var{regexp}
1616 @cindex searching for packages
1617 List the available packages whose name, synopsis, or description matches
1618 @var{regexp}. Print all the metadata of matching packages in
1619 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1620 GNU recutils manual}).
1622 This allows specific fields to be extracted using the @command{recsel}
1623 command, for instance:
1626 $ guix package -s malloc | recsel -p name,version
1634 Similarly, to show the name of all the packages available under the
1635 terms of the GNU@tie{}LGPL version 3:
1638 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1645 It is also possible to refine search results using several @code{-s}
1646 flags. For example, the following command returns a list of board
1650 $ guix package -s '\<board\>' -s game | recsel -p name
1655 If we were to omit @code{-s game}, we would also get software packages
1656 that deal with printed circuit boards; removing the angle brackets
1657 around @code{board} would further add packages that have to do with
1660 And now for a more elaborate example. The following command searches
1661 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1662 libraries, and prints the name and synopsis of the matching packages:
1665 $ guix package -s crypto -s library | \
1666 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1670 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1671 information on @dfn{selection expressions} for @code{recsel -e}.
1673 @item --show=@var{package}
1674 Show details about @var{package}, taken from the list of available packages, in
1675 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1679 $ guix package --show=python | recsel -p name,version
1687 You may also specify the full name of a package to only get details about a
1688 specific version of it:
1690 $ guix package --show=python-3.3.5 | recsel -p name,version
1697 @item --list-installed[=@var{regexp}]
1698 @itemx -I [@var{regexp}]
1699 List the currently installed packages in the specified profile, with the
1700 most recently installed packages shown last. When @var{regexp} is
1701 specified, list only installed packages whose name matches @var{regexp}.
1703 For each installed package, print the following items, separated by
1704 tabs: the package name, its version string, the part of the package that
1705 is installed (for instance, @code{out} for the default output,
1706 @code{include} for its headers, etc.), and the path of this package in
1709 @item --list-available[=@var{regexp}]
1710 @itemx -A [@var{regexp}]
1711 List packages currently available in the distribution for this system
1712 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
1713 installed packages whose name matches @var{regexp}.
1715 For each package, print the following items separated by tabs: its name,
1716 its version string, the parts of the package (@pxref{Packages with
1717 Multiple Outputs}), and the source location of its definition.
1719 @item --list-generations[=@var{pattern}]
1720 @itemx -l [@var{pattern}]
1721 Return a list of generations along with their creation dates; for each
1722 generation, show the installed packages, with the most recently
1723 installed packages shown last. Note that the zeroth generation is never
1726 For each installed package, print the following items, separated by
1727 tabs: the name of a package, its version string, the part of the package
1728 that is installed (@pxref{Packages with Multiple Outputs}), and the
1729 location of this package in the store.
1731 When @var{pattern} is used, the command returns only matching
1732 generations. Valid patterns include:
1735 @item @emph{Integers and comma-separated integers}. Both patterns denote
1736 generation numbers. For instance, @code{--list-generations=1} returns
1739 And @code{--list-generations=1,8,2} outputs three generations in the
1740 specified order. Neither spaces nor trailing commas are allowed.
1742 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
1743 specified generations and everything in between. Note that the start of
1744 a range must be smaller than its end.
1746 It is also possible to omit the endpoint. For example,
1747 @code{--list-generations=2..}, returns all generations starting from the
1750 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
1751 or months by passing an integer along with the first letter of the
1752 duration. For example, @code{--list-generations=20d} lists generations
1753 that are up to 20 days old.
1756 @item --delete-generations[=@var{pattern}]
1757 @itemx -d [@var{pattern}]
1758 When @var{pattern} is omitted, delete all generations except the current
1761 This command accepts the same patterns as @option{--list-generations}.
1762 When @var{pattern} is specified, delete the matching generations. When
1763 @var{pattern} specifies a duration, generations @emph{older} than the
1764 specified duration match. For instance, @code{--delete-generations=1m}
1765 deletes generations that are more than one month old.
1767 If the current generation matches, it is @emph{not} deleted. Also, the
1768 zeroth generation is never deleted.
1770 Note that deleting generations prevents rolling back to them.
1771 Consequently, this command must be used with care.
1775 Finally, since @command{guix package} may actually start build
1776 processes, it supports all the common build options (@pxref{Common Build
1777 Options}). It also supports package transformation options, such as
1778 @option{--with-source} (@pxref{Package Transformation Options}).
1779 However, note that package transformations are lost when upgrading; to
1780 preserve transformations across upgrades, you should define your own
1781 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
1782 (@pxref{Defining Packages}).
1786 @section Substitutes
1789 @cindex pre-built binaries
1790 Guix supports transparent source/binary deployment, which means that it
1791 can either build things locally, or download pre-built items from a
1792 server. We call these pre-built items @dfn{substitutes}---they are
1793 substitutes for local build results. In many cases, downloading a
1794 substitute is much faster than building things locally.
1796 Substitutes can be anything resulting from a derivation build
1797 (@pxref{Derivations}). Of course, in the common case, they are
1798 pre-built package binaries, but source tarballs, for instance, which
1799 also result from derivation builds, can be available as substitutes.
1801 The @code{hydra.gnu.org} server is a front-end to a build farm that
1802 builds packages from the GNU distribution continuously for some
1803 architectures, and makes them available as substitutes (@pxref{Emacs
1804 Hydra}, for information on how to query the continuous integration
1805 server). This is the
1806 default source of substitutes; it can be overridden by passing the
1807 @option{--substitute-urls} option either to @command{guix-daemon}
1808 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
1809 or to client tools such as @command{guix package}
1810 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
1813 Substitute URLs can be either HTTP or HTTPS@footnote{For HTTPS access,
1814 the Guile bindings of GnuTLS must be installed. @xref{Requirements}.}
1815 HTTPS is recommended because communications are encrypted; conversely,
1816 using HTTP makes all communications visible to an eavesdropper, who
1817 could use the information gathered to determine, for instance, whether
1818 your system has unpatched security vulnerabilities.
1821 @cindex digital signatures
1822 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
1824 must add its public key to the access control list (ACL) of archive
1825 imports, using the @command{guix archive} command (@pxref{Invoking guix
1826 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
1827 be compromised and to serve genuine substitutes.
1829 This public key is installed along with Guix, in
1830 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
1831 the installation prefix of Guix. If you installed Guix from source,
1832 make sure you checked the GPG signature of
1833 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
1834 Then, you can run something like this:
1837 # guix archive --authorize < hydra.gnu.org.pub
1840 Once this is in place, the output of a command like @code{guix build}
1841 should change from something like:
1844 $ guix build emacs --dry-run
1845 The following derivations would be built:
1846 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
1847 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
1848 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
1849 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
1857 $ guix build emacs --dry-run
1858 The following files would be downloaded:
1859 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
1860 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
1861 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
1862 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
1867 This indicates that substitutes from @code{hydra.gnu.org} are usable and
1868 will be downloaded, when possible, for future builds.
1870 Guix ignores substitutes that are not signed, or that are not signed by
1871 one of the keys listed in the ACL. It also detects and raises an error
1872 when attempting to use a substitute that has been tampered with.
1875 Substitutes are downloaded over HTTP or HTTPS.
1876 The @code{http_proxy} environment
1877 variable can be set in the environment of @command{guix-daemon} and is
1878 honored for downloads of substitutes. Note that the value of
1879 @code{http_proxy} in the environment where @command{guix build},
1880 @command{guix package}, and other client commands are run has
1881 @emph{absolutely no effect}.
1883 When using HTTPS, the server's X.509 certificate is @emph{not} validated
1884 (in other words, the server is not authenticated), contrary to what
1885 HTTPS clients such as Web browsers usually do. This is because Guix
1886 authenticates substitute information itself, as explained above, which
1887 is what we care about (whereas X.509 certificates are about
1888 authenticating bindings between domain names and public keys.)
1890 The substitute mechanism can be disabled globally by running
1891 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
1892 guix-daemon}). It can also be disabled temporarily by passing the
1893 @code{--no-substitutes} option to @command{guix package}, @command{guix
1894 build}, and other command-line tools.
1897 @unnumberedsubsec On Trusting Binaries
1899 Today, each individual's control over their own computing is at the
1900 mercy of institutions, corporations, and groups with enough power and
1901 determination to subvert the computing infrastructure and exploit its
1902 weaknesses. While using @code{hydra.gnu.org} substitutes can be
1903 convenient, we encourage users to also build on their own, or even run
1904 their own build farm, such that @code{hydra.gnu.org} is less of an
1905 interesting target. One way to help is by publishing the software you
1906 build using @command{guix publish} so that others have one more choice
1907 of server to download substitutes from (@pxref{Invoking guix publish}).
1909 Guix has the foundations to maximize build reproducibility
1910 (@pxref{Features}). In most cases, independent builds of a given
1911 package or derivation should yield bit-identical results. Thus, through
1912 a diverse set of independent package builds, we can strengthen the
1913 integrity of our systems. The @command{guix challenge} command aims to
1914 help users assess substitute servers, and to assist developers in
1915 finding out about non-deterministic package builds (@pxref{Invoking guix
1916 challenge}). Similarly, the @option{--check} option of @command{guix
1917 build} allows users to check whether previously-installed substitutes
1918 are genuine by rebuilding them locally (@pxref{build-check,
1919 @command{guix build --check}}).
1921 In the future, we want Guix to have support to publish and retrieve
1922 binaries to/from other users, in a peer-to-peer fashion. If you would
1923 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
1926 @node Packages with Multiple Outputs
1927 @section Packages with Multiple Outputs
1929 @cindex multiple-output packages
1930 @cindex package outputs
1932 Often, packages defined in Guix have a single @dfn{output}---i.e., the
1933 source package leads to exactly one directory in the store. When running
1934 @command{guix package -i glibc}, one installs the default output of the
1935 GNU libc package; the default output is called @code{out}, but its name
1936 can be omitted as shown in this command. In this particular case, the
1937 default output of @code{glibc} contains all the C header files, shared
1938 libraries, static libraries, Info documentation, and other supporting
1941 Sometimes it is more appropriate to separate the various types of files
1942 produced from a single source package into separate outputs. For
1943 instance, the GLib C library (used by GTK+ and related packages)
1944 installs more than 20 MiB of reference documentation as HTML pages.
1945 To save space for users who do not need it, the documentation goes to a
1946 separate output, called @code{doc}. To install the main GLib output,
1947 which contains everything but the documentation, one would run:
1950 guix package -i glib
1953 The command to install its documentation is:
1956 guix package -i glib:doc
1959 Some packages install programs with different ``dependency footprints''.
1960 For instance, the WordNet package installs both command-line tools and
1961 graphical user interfaces (GUIs). The former depend solely on the C
1962 library, whereas the latter depend on Tcl/Tk and the underlying X
1963 libraries. In this case, we leave the command-line tools in the default
1964 output, whereas the GUIs are in a separate output. This allows users
1965 who do not need the GUIs to save space. The @command{guix size} command
1966 can help find out about such situations (@pxref{Invoking guix size}).
1967 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
1969 There are several such multiple-output packages in the GNU distribution.
1970 Other conventional output names include @code{lib} for libraries and
1971 possibly header files, @code{bin} for stand-alone programs, and
1972 @code{debug} for debugging information (@pxref{Installing Debugging
1973 Files}). The outputs of a packages are listed in the third column of
1974 the output of @command{guix package --list-available} (@pxref{Invoking
1978 @node Invoking guix gc
1979 @section Invoking @command{guix gc}
1981 @cindex garbage collector
1982 Packages that are installed, but not used, may be @dfn{garbage-collected}.
1983 The @command{guix gc} command allows users to explicitly run the garbage
1984 collector to reclaim space from the @file{/gnu/store} directory. It is
1985 the @emph{only} way to remove files from @file{/gnu/store}---removing
1986 files or directories manually may break it beyond repair!
1988 The garbage collector has a set of known @dfn{roots}: any file under
1989 @file{/gnu/store} reachable from a root is considered @dfn{live} and
1990 cannot be deleted; any other file is considered @dfn{dead} and may be
1991 deleted. The set of garbage collector roots includes default user
1992 profiles, and may be augmented with @command{guix build --root}, for
1993 example (@pxref{Invoking guix build}).
1995 Prior to running @code{guix gc --collect-garbage} to make space, it is
1996 often useful to remove old generations from user profiles; that way, old
1997 package builds referenced by those generations can be reclaimed. This
1998 is achieved by running @code{guix package --delete-generations}
1999 (@pxref{Invoking guix package}).
2001 The @command{guix gc} command has three modes of operation: it can be
2002 used to garbage-collect any dead files (the default), to delete specific
2003 files (the @code{--delete} option), to print garbage-collector
2004 information, or for more advanced queries. The garbage collection
2005 options are as follows:
2008 @item --collect-garbage[=@var{min}]
2009 @itemx -C [@var{min}]
2010 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2011 sub-directories. This is the default operation when no option is
2014 When @var{min} is given, stop once @var{min} bytes have been collected.
2015 @var{min} may be a number of bytes, or it may include a unit as a
2016 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2017 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2019 When @var{min} is omitted, collect all the garbage.
2021 @item --free-space=@var{free}
2022 @itemx -F @var{free}
2023 Collect garbage until @var{free} space is available under
2024 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2025 as @code{500MiB}, as described above.
2027 When @var{free} or more is already available in @file{/gnu/store}, do
2028 nothing and exit immediately.
2032 Attempt to delete all the store files and directories specified as
2033 arguments. This fails if some of the files are not in the store, or if
2034 they are still live.
2036 @item --list-failures
2037 List store items corresponding to cached build failures.
2039 This prints nothing unless the daemon was started with
2040 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2041 @option{--cache-failures}}).
2043 @item --clear-failures
2044 Remove the specified store items from the failed-build cache.
2046 Again, this option only makes sense when the daemon is started with
2047 @option{--cache-failures}. Otherwise, it does nothing.
2050 Show the list of dead files and directories still present in the
2051 store---i.e., files and directories no longer reachable from any root.
2054 Show the list of live store files and directories.
2058 In addition, the references among existing store files can be queried:
2064 List the references (respectively, the referrers) of store files given
2070 List the requisites of the store files passed as arguments. Requisites
2071 include the store files themselves, their references, and the references
2072 of these, recursively. In other words, the returned list is the
2073 @dfn{transitive closure} of the store files.
2075 @xref{Invoking guix size}, for a tool to profile the size of the closure
2076 of an element. @xref{Invoking guix graph}, for a tool to visualize
2077 the graph of references.
2081 Lastly, the following options allow you to check the integrity of the
2082 store and to control disk usage.
2086 @item --verify[=@var{options}]
2087 @cindex integrity, of the store
2088 @cindex integrity checking
2089 Verify the integrity of the store.
2091 By default, make sure that all the store items marked as valid in the
2092 database of the daemon actually exist in @file{/gnu/store}.
2094 When provided, @var{options} must be a comma-separated list containing one
2095 or more of @code{contents} and @code{repair}.
2097 When passing @option{--verify=contents}, the daemon computse the
2098 content hash of each store item and compares it against its hash in the
2099 database. Hash mismatches are reported as data corruptions. Because it
2100 traverses @emph{all the files in the store}, this command can take a
2101 long time, especially on systems with a slow disk drive.
2103 @cindex repairing the store
2104 Using @option{--verify=repair} or @option{--verify=contents,repair}
2105 causes the daemon to try to repair corrupt store items by fetching
2106 substitutes for them (@pxref{Substitutes}). Because repairing is not
2107 atomic, and thus potentially dangerous, it is available only to the
2108 system administrator.
2111 @cindex deduplication
2112 Optimize the store by hard-linking identical files---this is
2113 @dfn{deduplication}.
2115 The daemon performs deduplication after each successful build or archive
2116 import, unless it was started with @code{--disable-deduplication}
2117 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2118 this option is primarily useful when the daemon was running with
2119 @code{--disable-deduplication}.
2123 @node Invoking guix pull
2124 @section Invoking @command{guix pull}
2126 Packages are installed or upgraded to the latest version available in
2127 the distribution currently available on your local machine. To update
2128 that distribution, along with the Guix tools, you must run @command{guix
2129 pull}: the command downloads the latest Guix source code and package
2130 descriptions, and deploys it.
2132 On completion, @command{guix package} will use packages and package
2133 versions from this just-retrieved copy of Guix. Not only that, but all
2134 the Guix commands and Scheme modules will also be taken from that latest
2135 version. New @command{guix} sub-commands added by the update also
2138 Any user can update their Guix copy using @command{guix pull}, and the
2139 effect is limited to the user who run @command{guix pull}. For
2140 instance, when user @code{root} runs @command{guix pull}, this has no
2141 effect on the version of Guix that user @code{alice} sees, and vice
2142 versa@footnote{Under the hood, @command{guix pull} updates the
2143 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2144 and the @command{guix} command loads code from there.}.
2146 The @command{guix pull} command is usually invoked with no arguments,
2147 but it supports the following options:
2151 Produce verbose output, writing build logs to the standard error output.
2153 @item --url=@var{url}
2154 Download the source tarball of Guix from @var{url}.
2156 By default, the tarball is taken from its canonical address at
2157 @code{gnu.org}, for the stable branch of Guix.
2160 Use the bootstrap Guile to build the latest Guix. This option is only
2161 useful to Guix developers.
2165 @node Invoking guix archive
2166 @section Invoking @command{guix archive}
2168 The @command{guix archive} command allows users to @dfn{export} files
2169 from the store into a single archive, and to later @dfn{import} them.
2170 In particular, it allows store files to be transferred from one machine
2171 to the store on another machine.
2173 To export store files as an archive to standard output, run:
2176 guix archive --export @var{options} @var{specifications}...
2179 @var{specifications} may be either store file names or package
2180 specifications, as for @command{guix package} (@pxref{Invoking guix
2181 package}). For instance, the following command creates an archive
2182 containing the @code{gui} output of the @code{git} package and the main
2183 output of @code{emacs}:
2186 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2189 If the specified packages are not built yet, @command{guix archive}
2190 automatically builds them. The build process may be controlled with the
2191 common build options (@pxref{Common Build Options}).
2193 To transfer the @code{emacs} package to a machine connected over SSH,
2197 guix archive --export -r emacs | ssh the-machine guix archive --import
2201 Similarly, a complete user profile may be transferred from one machine
2202 to another like this:
2205 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2206 ssh the-machine guix-archive --import
2210 However, note that, in both examples, all of @code{emacs} and the
2211 profile as well as all of their dependencies are transferred (due to
2212 @code{-r}), regardless of what is already available in the store on the
2213 target machine. The @code{--missing} option can help figure out which
2214 items are missing from the target store.
2216 Archives are stored in the ``Nix archive'' or ``Nar'' format, which is
2217 comparable in spirit to `tar', but with a few noteworthy differences
2218 that make it more appropriate for our purposes. First, rather than
2219 recording all Unix metadata for each file, the Nar format only mentions
2220 the file type (regular, directory, or symbolic link); Unix permissions
2221 and owner/group are dismissed. Second, the order in which directory
2222 entries are stored always follows the order of file names according to
2223 the C locale collation order. This makes archive production fully
2226 When exporting, the daemon digitally signs the contents of the archive,
2227 and that digital signature is appended. When importing, the daemon
2228 verifies the signature and rejects the import in case of an invalid
2229 signature or if the signing key is not authorized.
2230 @c FIXME: Add xref to daemon doc about signatures.
2232 The main options are:
2236 Export the specified store files or packages (see below.) Write the
2237 resulting archive to the standard output.
2239 Dependencies are @emph{not} included in the output, unless
2240 @code{--recursive} is passed.
2244 When combined with @code{--export}, this instructs @command{guix
2245 archive} to include dependencies of the given items in the archive.
2246 Thus, the resulting archive is self-contained: it contains the closure
2247 of the exported store items.
2250 Read an archive from the standard input, and import the files listed
2251 therein into the store. Abort if the archive has an invalid digital
2252 signature, or if it is signed by a public key not among the authorized
2253 keys (see @code{--authorize} below.)
2256 Read a list of store file names from the standard input, one per line,
2257 and write on the standard output the subset of these files missing from
2260 @item --generate-key[=@var{parameters}]
2261 @cindex signing, archives
2262 Generate a new key pair for the daemon. This is a prerequisite before
2263 archives can be exported with @code{--export}. Note that this operation
2264 usually takes time, because it needs to gather enough entropy to
2265 generate the key pair.
2267 The generated key pair is typically stored under @file{/etc/guix}, in
2268 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2269 key, which must be kept secret.) When @var{parameters} is omitted,
2270 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2271 versions before 1.6.0, it is a 4096-bit RSA key.
2272 Alternatively, @var{parameters} can specify
2273 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2274 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2275 Libgcrypt Reference Manual}).
2278 @cindex authorizing, archives
2279 Authorize imports signed by the public key passed on standard input.
2280 The public key must be in ``s-expression advanced format''---i.e., the
2281 same format as the @file{signing-key.pub} file.
2283 The list of authorized keys is kept in the human-editable file
2284 @file{/etc/guix/acl}. The file contains
2285 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2286 s-expressions''} and is structured as an access-control list in the
2287 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2290 @item --extract=@var{directory}
2291 @itemx -x @var{directory}
2292 Read a single-item archive as served by substitute servers
2293 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2294 low-level operation needed in only very narrow use cases; see below.
2296 For example, the following command extracts the substitute for Emacs
2297 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2301 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2302 | bunzip2 | guix archive -x /tmp/emacs
2305 Single-item archives are different from multiple-item archives produced
2306 by @command{guix archive --export}; they contain a single store item,
2307 and they do @emph{not} embed a signature. Thus this operation does
2308 @emph{no} signature verification and its output should be considered
2311 The primary purpose of this operation is to facilitate inspection of
2312 archive contents coming from possibly untrusted substitute servers.
2316 @c *********************************************************************
2319 @c *********************************************************************
2320 @node Programming Interface
2321 @chapter Programming Interface
2323 GNU Guix provides several Scheme programming interfaces (APIs) to
2324 define, build, and query packages. The first interface allows users to
2325 write high-level package definitions. These definitions refer to
2326 familiar packaging concepts, such as the name and version of a package,
2327 its build system, and its dependencies. These definitions can then be
2328 turned into concrete build actions.
2330 Build actions are performed by the Guix daemon, on behalf of users. In a
2331 standard setup, the daemon has write access to the store---the
2332 @file{/gnu/store} directory---whereas users do not. The recommended
2333 setup also has the daemon perform builds in chroots, under a specific
2334 build users, to minimize interference with the rest of the system.
2337 Lower-level APIs are available to interact with the daemon and the
2338 store. To instruct the daemon to perform a build action, users actually
2339 provide it with a @dfn{derivation}. A derivation is a low-level
2340 representation of the build actions to be taken, and the environment in
2341 which they should occur---derivations are to package definitions what
2342 assembly is to C programs. The term ``derivation'' comes from the fact
2343 that build results @emph{derive} from them.
2345 This chapter describes all these APIs in turn, starting from high-level
2346 package definitions.
2349 * Defining Packages:: Defining new packages.
2350 * Build Systems:: Specifying how packages are built.
2351 * The Store:: Manipulating the package store.
2352 * Derivations:: Low-level interface to package derivations.
2353 * The Store Monad:: Purely functional interface to the store.
2354 * G-Expressions:: Manipulating build expressions.
2357 @node Defining Packages
2358 @section Defining Packages
2360 The high-level interface to package definitions is implemented in the
2361 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2362 example, the package definition, or @dfn{recipe}, for the GNU Hello
2363 package looks like this:
2366 (define-module (gnu packages hello)
2367 #:use-module (guix packages)
2368 #:use-module (guix download)
2369 #:use-module (guix build-system gnu)
2370 #:use-module (guix licenses)
2371 #:use-module (gnu packages gawk))
2373 (define-public hello
2379 (uri (string-append "mirror://gnu/hello/hello-" version
2383 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2384 (build-system gnu-build-system)
2385 (arguments `(#:configure-flags '("--enable-silent-rules")))
2386 (inputs `(("gawk" ,gawk)))
2387 (synopsis "Hello, GNU world: An example GNU package")
2388 (description "Guess what GNU Hello prints!")
2389 (home-page "http://www.gnu.org/software/hello/")
2394 Without being a Scheme expert, the reader may have guessed the meaning
2395 of the various fields here. This expression binds the variable
2396 @code{hello} to a @code{<package>} object, which is essentially a record
2397 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2398 This package object can be inspected using procedures found in the
2399 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2400 returns---surprise!---@code{"hello"}.
2402 With luck, you may be able to import part or all of the definition of
2403 the package you are interested in from another repository, using the
2404 @code{guix import} command (@pxref{Invoking guix import}).
2406 In the example above, @var{hello} is defined in a module of its own,
2407 @code{(gnu packages hello)}. Technically, this is not strictly
2408 necessary, but it is convenient to do so: all the packages defined in
2409 modules under @code{(gnu packages @dots{})} are automatically known to
2410 the command-line tools (@pxref{Package Modules}).
2412 There are a few points worth noting in the above package definition:
2416 The @code{source} field of the package is an @code{<origin>} object
2417 (@pxref{origin Reference}, for the complete reference).
2418 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2419 meaning that the source is a file to be downloaded over FTP or HTTP.
2421 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2422 the GNU mirrors defined in @code{(guix download)}.
2424 The @code{sha256} field specifies the expected SHA256 hash of the file
2425 being downloaded. It is mandatory, and allows Guix to check the
2426 integrity of the file. The @code{(base32 @dots{})} form introduces the
2427 base32 representation of the hash. You can obtain this information with
2428 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2429 hash} (@pxref{Invoking guix hash}).
2432 When needed, the @code{origin} form can also have a @code{patches} field
2433 listing patches to be applied, and a @code{snippet} field giving a
2434 Scheme expression to modify the source code.
2437 @cindex GNU Build System
2438 The @code{build-system} field specifies the procedure to build the
2439 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2440 represents the familiar GNU Build System, where packages may be
2441 configured, built, and installed with the usual @code{./configure &&
2442 make && make check && make install} command sequence.
2445 The @code{arguments} field specifies options for the build system
2446 (@pxref{Build Systems}). Here it is interpreted by
2447 @var{gnu-build-system} as a request run @file{configure} with the
2448 @code{--enable-silent-rules} flag.
2451 The @code{inputs} field specifies inputs to the build process---i.e.,
2452 build-time or run-time dependencies of the package. Here, we define an
2453 input called @code{"gawk"} whose value is that of the @var{gawk}
2454 variable; @var{gawk} is itself bound to a @code{<package>} object.
2456 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2457 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2458 of ensuring that they are present (@pxref{Build Systems}).
2460 However, any other dependencies need to be specified in the
2461 @code{inputs} field. Any dependency not specified here will simply be
2462 unavailable to the build process, possibly leading to a build failure.
2465 @xref{package Reference}, for a full description of possible fields.
2467 Once a package definition is in place, the
2468 package may actually be built using the @code{guix build} command-line
2469 tool (@pxref{Invoking guix build}). You can easily jump back to the
2470 package definition using the @command{guix edit} command
2471 (@pxref{Invoking guix edit}).
2472 @xref{Packaging Guidelines}, for
2473 more information on how to test package definitions, and
2474 @ref{Invoking guix lint}, for information on how to check a definition
2475 for style conformance.
2477 Finally, updating the package definition to a new upstream version
2478 can be partly automated by the @command{guix refresh} command
2479 (@pxref{Invoking guix refresh}).
2481 Behind the scenes, a derivation corresponding to the @code{<package>}
2482 object is first computed by the @code{package-derivation} procedure.
2483 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
2484 The build actions it prescribes may then be realized by using the
2485 @code{build-derivations} procedure (@pxref{The Store}).
2487 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
2488 Return the @code{<derivation>} object of @var{package} for @var{system}
2489 (@pxref{Derivations}).
2491 @var{package} must be a valid @code{<package>} object, and @var{system}
2492 must be a string denoting the target system type---e.g.,
2493 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
2494 must be a connection to the daemon, which operates on the store
2495 (@pxref{The Store}).
2499 @cindex cross-compilation
2500 Similarly, it is possible to compute a derivation that cross-builds a
2501 package for some other system:
2503 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
2504 @var{package} @var{target} [@var{system}]
2505 Return the @code{<derivation>} object of @var{package} cross-built from
2506 @var{system} to @var{target}.
2508 @var{target} must be a valid GNU triplet denoting the target hardware
2509 and operating system, such as @code{"mips64el-linux-gnu"}
2510 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
2511 Configure and Build System}).
2515 * package Reference :: The package data type.
2516 * origin Reference:: The origin data type.
2520 @node package Reference
2521 @subsection @code{package} Reference
2523 This section summarizes all the options available in @code{package}
2524 declarations (@pxref{Defining Packages}).
2526 @deftp {Data Type} package
2527 This is the data type representing a package recipe.
2531 The name of the package, as a string.
2533 @item @code{version}
2534 The version of the package, as a string.
2537 An object telling how the source code for the package should be
2538 acquired. Most of the time, this is an @code{origin} object, which
2539 denotes a file fetched from the Internet (@pxref{origin Reference}). It
2540 can also be any other ``file-like'' object such as a @code{local-file},
2541 which denotes a file from the local file system (@pxref{G-Expressions,
2542 @code{local-file}}).
2544 @item @code{build-system}
2545 The build system that should be used to build the package (@pxref{Build
2548 @item @code{arguments} (default: @code{'()})
2549 The arguments that should be passed to the build system. This is a
2550 list, typically containing sequential keyword-value pairs.
2552 @item @code{inputs} (default: @code{'()})
2553 @itemx @code{native-inputs} (default: @code{'()})
2554 @itemx @code{propagated-inputs} (default: @code{'()})
2555 @cindex inputs, of packages
2556 These fields list dependencies of the package. Each one is a list of
2557 tuples, where each tuple has a label for the input (a string) as its
2558 first element, a package, origin, or derivation as its second element,
2559 and optionally the name of the output thereof that should be used, which
2560 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
2561 more on package outputs). For example, the list below specifies three
2565 `(("libffi" ,libffi)
2566 ("libunistring" ,libunistring)
2567 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
2570 @cindex cross compilation, package dependencies
2571 The distinction between @code{native-inputs} and @code{inputs} is
2572 necessary when considering cross-compilation. When cross-compiling,
2573 dependencies listed in @code{inputs} are built for the @emph{target}
2574 architecture; conversely, dependencies listed in @code{native-inputs}
2575 are built for the architecture of the @emph{build} machine.
2577 @code{native-inputs} is typically used to list tools needed at
2578 build time, but not at run time, such as Autoconf, Automake, pkg-config,
2579 Gettext, or Bison. @command{guix lint} can report likely mistakes in
2580 this area (@pxref{Invoking guix lint}).
2582 @anchor{package-propagated-inputs}
2583 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
2584 specified packages will be automatically installed alongside the package
2585 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
2586 package}}, for information on how @command{guix package} deals with
2589 For example this is necessary when a C/C++ library needs headers of
2590 another library to compile, or when a pkg-config file refers to another
2591 one @i{via} its @code{Requires} field.
2593 Another example where @code{propagated-inputs} is useful is for languages
2594 that lack a facility to record the run-time search path akin to the
2595 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, GHC, and
2596 more. To ensure that libraries written in those languages can find
2597 library code they depend on at run time, run-time dependencies must be
2598 listed in @code{propagated-inputs} rather than @code{inputs}.
2600 @item @code{self-native-input?} (default: @code{#f})
2601 This is a Boolean field telling whether the package should use itself as
2602 a native input when cross-compiling.
2604 @item @code{outputs} (default: @code{'("out")})
2605 The list of output names of the package. @xref{Packages with Multiple
2606 Outputs}, for typical uses of additional outputs.
2608 @item @code{native-search-paths} (default: @code{'()})
2609 @itemx @code{search-paths} (default: @code{'()})
2610 A list of @code{search-path-specification} objects describing
2611 search-path environment variables honored by the package.
2613 @item @code{replacement} (default: @code{#f})
2614 This must be either @code{#f} or a package object that will be used as a
2615 @dfn{replacement} for this package. @xref{Security Updates, grafts},
2618 @item @code{synopsis}
2619 A one-line description of the package.
2621 @item @code{description}
2622 A more elaborate description of the package.
2624 @item @code{license}
2625 The license of the package; a value from @code{(guix licenses)},
2626 or a list of such values.
2628 @item @code{home-page}
2629 The URL to the home-page of the package, as a string.
2631 @item @code{supported-systems} (default: @var{%supported-systems})
2632 The list of systems supported by the package, as strings of the form
2633 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
2635 @item @code{maintainers} (default: @code{'()})
2636 The list of maintainers of the package, as @code{maintainer} objects.
2638 @item @code{location} (default: source location of the @code{package} form)
2639 The source location of the package. It is useful to override this when
2640 inheriting from another package, in which case this field is not
2641 automatically corrected.
2646 @node origin Reference
2647 @subsection @code{origin} Reference
2649 This section summarizes all the options available in @code{origin}
2650 declarations (@pxref{Defining Packages}).
2652 @deftp {Data Type} origin
2653 This is the data type representing a source code origin.
2657 An object containing the URI of the source. The object type depends on
2658 the @code{method} (see below). For example, when using the
2659 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
2660 values are: a URL represented as a string, or a list thereof.
2663 A procedure that handles the URI.
2668 @item @var{url-fetch} from @code{(guix download)}
2669 download a file from the HTTP, HTTPS, or FTP URL specified in the
2672 @item @var{git-fetch} from @code{(guix git-download)}
2673 clone the Git version control repository, and check out the revision
2674 specified in the @code{uri} field as a @code{git-reference} object; a
2675 @code{git-reference} looks like this:
2679 (url "git://git.debian.org/git/pkg-shadow/shadow")
2680 (commit "v4.1.5.1"))
2685 A bytevector containing the SHA-256 hash of the source. Typically the
2686 @code{base32} form is used here to generate the bytevector from a
2689 @item @code{file-name} (default: @code{#f})
2690 The file name under which the source code should be saved. When this is
2691 @code{#f}, a sensible default value will be used in most cases. In case
2692 the source is fetched from a URL, the file name from the URL will be
2693 used. For version control checkouts, it is recommended to provide the
2694 file name explicitly because the default is not very descriptive.
2696 @item @code{patches} (default: @code{'()})
2697 A list of file names containing patches to be applied to the source.
2699 @item @code{snippet} (default: @code{#f})
2700 A quoted piece of code that will be run in the source directory to make
2701 any modifications, which is sometimes more convenient than a patch.
2703 @item @code{patch-flags} (default: @code{'("-p1")})
2704 A list of command-line flags that should be passed to the @code{patch}
2707 @item @code{patch-inputs} (default: @code{#f})
2708 Input packages or derivations to the patching process. When this is
2709 @code{#f}, the usual set of inputs necessary for patching are provided,
2710 such as GNU@tie{}Patch.
2712 @item @code{modules} (default: @code{'()})
2713 A list of Guile modules that should be loaded during the patching
2714 process and while running the code in the @code{snippet} field.
2716 @item @code{imported-modules} (default: @code{'()})
2717 The list of Guile modules to import in the patch derivation, for use by
2720 @item @code{patch-guile} (default: @code{#f})
2721 The Guile package that should be used in the patching process. When
2722 this is @code{#f}, a sensible default is used.
2728 @section Build Systems
2730 @cindex build system
2731 Each package definition specifies a @dfn{build system} and arguments for
2732 that build system (@pxref{Defining Packages}). This @code{build-system}
2733 field represents the build procedure of the package, as well as implicit
2734 dependencies of that build procedure.
2736 Build systems are @code{<build-system>} objects. The interface to
2737 create and manipulate them is provided by the @code{(guix build-system)}
2738 module, and actual build systems are exported by specific modules.
2740 @cindex bag (low-level package representation)
2741 Under the hood, build systems first compile package objects to
2742 @dfn{bags}. A @dfn{bag} is like a package, but with less
2743 ornamentation---in other words, a bag is a lower-level representation of
2744 a package, which includes all the inputs of that package, including some
2745 that were implicitly added by the build system. This intermediate
2746 representation is then compiled to a derivation (@pxref{Derivations}).
2748 Build systems accept an optional list of @dfn{arguments}. In package
2749 definitions, these are passed @i{via} the @code{arguments} field
2750 (@pxref{Defining Packages}). They are typically keyword arguments
2751 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
2752 Guile Reference Manual}). The value of these arguments is usually
2753 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
2754 by the daemon (@pxref{Derivations}).
2756 The main build system is @var{gnu-build-system}, which implements the
2757 standard build procedure for GNU and many other packages. It
2758 is provided by the @code{(guix build-system gnu)} module.
2760 @defvr {Scheme Variable} gnu-build-system
2761 @var{gnu-build-system} represents the GNU Build System, and variants
2762 thereof (@pxref{Configuration, configuration and makefile conventions,,
2763 standards, GNU Coding Standards}).
2765 @cindex build phases
2766 In a nutshell, packages using it are configured, built, and installed with
2767 the usual @code{./configure && make && make check && make install}
2768 command sequence. In practice, a few additional steps are often needed.
2769 All these steps are split up in separate @dfn{phases},
2770 notably@footnote{Please see the @code{(guix build gnu-build-system)}
2771 modules for more details about the build phases.}:
2775 Unpack the source tarball, and change the current directory to the
2776 extracted source tree. If the source is actually a directory, copy it
2777 to the build tree, and enter that directory.
2779 @item patch-source-shebangs
2780 Patch shebangs encountered in source files so they refer to the right
2781 store file names. For instance, this changes @code{#!/bin/sh} to
2782 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
2785 Run the @file{configure} script with a number of default options, such
2786 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
2787 by the @code{#:configure-flags} argument.
2790 Run @code{make} with the list of flags specified with
2791 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
2792 (the default), build with @code{make -j}.
2795 Run @code{make check}, or some other target specified with
2796 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
2797 @code{#:parallel-tests?} argument is true (the default), run @code{make
2801 Run @code{make install} with the flags listed in @code{#:make-flags}.
2803 @item patch-shebangs
2804 Patch shebangs on the installed executable files.
2807 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
2808 is false), copying them to the @code{debug} output when available
2809 (@pxref{Installing Debugging Files}).
2812 @vindex %standard-phases
2813 The build-side module @code{(guix build gnu-build-system)} defines
2814 @var{%standard-phases} as the default list of build phases.
2815 @var{%standard-phases} is a list of symbol/procedure pairs, where the
2816 procedure implements the actual phase.
2818 The list of phases used for a particular package can be changed with the
2819 @code{#:phases} parameter. For instance, passing:
2822 #:phases (modify-phases %standard-phases (delete 'configure))
2825 means that all the phases described above will be used, except the
2826 @code{configure} phase.
2828 In addition, this build system ensures that the ``standard'' environment
2829 for GNU packages is available. This includes tools such as GCC, libc,
2830 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
2831 build-system gnu)} module for a complete list). We call these the
2832 @dfn{implicit inputs} of a package, because package definitions do not
2833 have to mention them.
2836 Other @code{<build-system>} objects are defined to support other
2837 conventions and tools used by free software packages. They inherit most
2838 of @var{gnu-build-system}, and differ mainly in the set of inputs
2839 implicitly added to the build process, and in the list of phases
2840 executed. Some of these build systems are listed below.
2842 @defvr {Scheme Variable} ant-build-system
2843 This variable is exported by @code{(guix build-system ant)}. It
2844 implements the build procedure for Java packages that can be built with
2845 @url{http://ant.apache.org/, Ant build tool}.
2847 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
2848 provided by the @code{icedtea} package to the set of inputs. Different
2849 packages can be specified with the @code{#:ant} and @code{#:jdk}
2850 parameters, respectively.
2852 When the original package does not provide a suitable Ant build file,
2853 the parameter @code{#:jar-name} can be used to generate a minimal Ant
2854 build file @file{build.xml} with tasks to build the specified jar
2857 The parameter @code{#:build-target} can be used to specify the Ant task
2858 that should be run during the @code{build} phase. By default the
2859 ``jar'' task will be run.
2863 @defvr {Scheme Variable} cmake-build-system
2864 This variable is exported by @code{(guix build-system cmake)}. It
2865 implements the build procedure for packages using the
2866 @url{http://www.cmake.org, CMake build tool}.
2868 It automatically adds the @code{cmake} package to the set of inputs.
2869 Which package is used can be specified with the @code{#:cmake}
2872 The @code{#:configure-flags} parameter is taken as a list of flags
2873 passed to the @command{cmake} command. The @code{#:build-type}
2874 parameter specifies in abstract terms the flags passed to the compiler;
2875 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
2876 debugging information''), which roughly means that code is compiled with
2877 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
2880 @defvr {Scheme Variable} glib-or-gtk-build-system
2881 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
2882 is intended for use with packages making use of GLib or GTK+.
2884 This build system adds the following two phases to the ones defined by
2885 @var{gnu-build-system}:
2888 @item glib-or-gtk-wrap
2889 The phase @code{glib-or-gtk-wrap} ensures that programs in
2890 @file{bin/} are able to find GLib ``schemas'' and
2891 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
2892 modules}. This is achieved by wrapping the programs in launch scripts
2893 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
2894 environment variables.
2896 It is possible to exclude specific package outputs from that wrapping
2897 process by listing their names in the
2898 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
2899 when an output is known not to contain any GLib or GTK+ binaries, and
2900 where wrapping would gratuitously add a dependency of that output on
2903 @item glib-or-gtk-compile-schemas
2904 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
2905 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
2906 GSettings schemas} of GLib are compiled. Compilation is performed by the
2907 @command{glib-compile-schemas} program. It is provided by the package
2908 @code{glib:bin} which is automatically imported by the build system.
2909 The @code{glib} package providing @command{glib-compile-schemas} can be
2910 specified with the @code{#:glib} parameter.
2913 Both phases are executed after the @code{install} phase.
2916 @defvr {Scheme Variable} python-build-system
2917 This variable is exported by @code{(guix build-system python)}. It
2918 implements the more or less standard build procedure used by Python
2919 packages, which consists in running @code{python setup.py build} and
2920 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
2922 For packages that install stand-alone Python programs under @code{bin/},
2923 it takes care of wrapping these programs so that their @code{PYTHONPATH}
2924 environment variable points to all the Python libraries they depend on.
2926 Which Python package is used to perform the build can be specified with
2927 the @code{#:python} parameter. This is a useful way to force a package
2928 to be built for a specific version of the Python interpreter, which
2929 might be necessary if the package is only compatible with a single
2930 interpreter version.
2933 @defvr {Scheme Variable} perl-build-system
2934 This variable is exported by @code{(guix build-system perl)}. It
2935 implements the standard build procedure for Perl packages, which either
2936 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
2937 followed by @code{Build} and @code{Build install}; or in running
2938 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
2939 @code{make} and @code{make install}, depending on which of
2940 @code{Build.PL} or @code{Makefile.PL} is present in the package
2941 distribution. Preference is given to the former if both @code{Build.PL}
2942 and @code{Makefile.PL} exist in the package distribution. This
2943 preference can be reversed by specifying @code{#t} for the
2944 @code{#:make-maker?} parameter.
2946 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
2947 passes flags specified by the @code{#:make-maker-flags} or
2948 @code{#:module-build-flags} parameter, respectively.
2950 Which Perl package is used can be specified with @code{#:perl}.
2953 @defvr {Scheme Variable} r-build-system
2954 This variable is exported by @code{(guix build-system r)}. It
2955 implements the build procedure used by @uref{http://r-project.org, R}
2956 packages, which essentially is little more than running @code{R CMD
2957 INSTALL --library=/gnu/store/@dots{}} in an environment where
2958 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
2959 are run after installation using the R function
2960 @code{tools::testInstalledPackage}.
2963 @defvr {Scheme Variable} ruby-build-system
2964 This variable is exported by @code{(guix build-system ruby)}. It
2965 implements the RubyGems build procedure used by Ruby packages, which
2966 involves running @code{gem build} followed by @code{gem install}.
2968 The @code{source} field of a package that uses this build system
2969 typically references a gem archive, since this is the format that Ruby
2970 developers use when releasing their software. The build system unpacks
2971 the gem archive, potentially patches the source, runs the test suite,
2972 repackages the gem, and installs it. Additionally, directories and
2973 tarballs may be referenced to allow building unreleased gems from Git or
2974 a traditional source release tarball.
2976 Which Ruby package is used can be specified with the @code{#:ruby}
2977 parameter. A list of additional flags to be passed to the @command{gem}
2978 command can be specified with the @code{#:gem-flags} parameter.
2981 @defvr {Scheme Variable} waf-build-system
2982 This variable is exported by @code{(guix build-system waf)}. It
2983 implements a build procedure around the @code{waf} script. The common
2984 phases---@code{configure}, @code{build}, and @code{install}---are
2985 implemented by passing their names as arguments to the @code{waf}
2988 The @code{waf} script is executed by the Python interpreter. Which
2989 Python package is used to run the script can be specified with the
2990 @code{#:python} parameter.
2993 @defvr {Scheme Variable} haskell-build-system
2994 This variable is exported by @code{(guix build-system haskell)}. It
2995 implements the Cabal build procedure used by Haskell packages, which
2996 involves running @code{runhaskell Setup.hs configure
2997 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
2998 Instead of installing the package by running @code{runhaskell Setup.hs
2999 install}, to avoid trying to register libraries in the read-only
3000 compiler store directory, the build system uses @code{runhaskell
3001 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3002 addition, the build system generates the package documentation by
3003 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3004 is passed. Optional Haddock parameters can be passed with the help of
3005 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3006 not found, the build system looks for @code{Setup.lhs} instead.
3008 Which Haskell compiler is used can be specified with the @code{#:haskell}
3009 parameter which defaults to @code{ghc}.
3012 @defvr {Scheme Variable} emacs-build-system
3013 This variable is exported by @code{(guix build-system emacs)}. It
3014 implements an installation procedure similar to the packaging system
3015 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3017 It first creates the @code{@var{package}-autoloads.el} file, then it
3018 byte compiles all Emacs Lisp files. Differently from the Emacs
3019 packaging system, the Info documentation files are moved to the standard
3020 documentation directory and the @file{dir} file is deleted. Each
3021 package is installed in its own directory under
3022 @file{share/emacs/site-lisp/guix.d}.
3025 Lastly, for packages that do not need anything as sophisticated, a
3026 ``trivial'' build system is provided. It is trivial in the sense that
3027 it provides basically no support: it does not pull any implicit inputs,
3028 and does not have a notion of build phases.
3030 @defvr {Scheme Variable} trivial-build-system
3031 This variable is exported by @code{(guix build-system trivial)}.
3033 This build system requires a @code{#:builder} argument. This argument
3034 must be a Scheme expression that builds the package output(s)---as
3035 with @code{build-expression->derivation} (@pxref{Derivations,
3036 @code{build-expression->derivation}}).
3046 Conceptually, the @dfn{store} is the place where derivations that have
3047 been built successfully are stored---by default, @file{/gnu/store}.
3048 Sub-directories in the store are referred to as @dfn{store items} or
3049 sometimes @dfn{store paths}. The store has an associated database that
3050 contains information such as the store paths referred to by each store
3051 path, and the list of @emph{valid} store items---results of successful
3052 builds. This database resides in @file{@var{localstatedir}/guix/db},
3053 where @var{localstatedir} is the state directory specified @i{via}
3054 @option{--localstatedir} at configure time, usually @file{/var}.
3056 The store is @emph{always} accessed by the daemon on behalf of its clients
3057 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3058 connect to the daemon over a Unix-domain socket, send requests to it,
3059 and read the result---these are remote procedure calls, or RPCs.
3062 Users must @emph{never} modify files under @file{/gnu/store} directly.
3063 This would lead to inconsistencies and break the immutability
3064 assumptions of Guix's functional model (@pxref{Introduction}).
3066 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3067 how to check the integrity of the store and attempt recovery from
3068 accidental modifications.
3071 The @code{(guix store)} module provides procedures to connect to the
3072 daemon, and to perform RPCs. These are described below.
3074 @deffn {Scheme Procedure} open-connection [@var{file}] [#:reserve-space? #t]
3075 Connect to the daemon over the Unix-domain socket at @var{file}. When
3076 @var{reserve-space?} is true, instruct it to reserve a little bit of
3077 extra space on the file system so that the garbage collector can still
3078 operate should the disk become full. Return a server object.
3080 @var{file} defaults to @var{%default-socket-path}, which is the normal
3081 location given the options that were passed to @command{configure}.
3084 @deffn {Scheme Procedure} close-connection @var{server}
3085 Close the connection to @var{server}.
3088 @defvr {Scheme Variable} current-build-output-port
3089 This variable is bound to a SRFI-39 parameter, which refers to the port
3090 where build and error logs sent by the daemon should be written.
3093 Procedures that make RPCs all take a server object as their first
3096 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3097 @cindex invalid store items
3098 Return @code{#t} when @var{path} designates a valid store item and
3099 @code{#f} otherwise (an invalid item may exist on disk but still be
3100 invalid, for instance because it is the result of an aborted or failed
3103 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3104 prefixed by the store directory (@file{/gnu/store}).
3107 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3108 Add @var{text} under file @var{name} in the store, and return its store
3109 path. @var{references} is the list of store paths referred to by the
3110 resulting store path.
3113 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3114 Build @var{derivations} (a list of @code{<derivation>} objects or
3115 derivation paths), and return when the worker is done building them.
3116 Return @code{#t} on success.
3119 Note that the @code{(guix monads)} module provides a monad as well as
3120 monadic versions of the above procedures, with the goal of making it
3121 more convenient to work with code that accesses the store (@pxref{The
3125 @i{This section is currently incomplete.}
3128 @section Derivations
3131 Low-level build actions and the environment in which they are performed
3132 are represented by @dfn{derivations}. A derivation contains the
3133 following pieces of information:
3137 The outputs of the derivation---derivations produce at least one file or
3138 directory in the store, but may produce more.
3141 The inputs of the derivations, which may be other derivations or plain
3142 files in the store (patches, build scripts, etc.)
3145 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3148 The file name of a build script in the store, along with the arguments
3152 A list of environment variables to be defined.
3156 @cindex derivation path
3157 Derivations allow clients of the daemon to communicate build actions to
3158 the store. They exist in two forms: as an in-memory representation,
3159 both on the client- and daemon-side, and as files in the store whose
3160 name end in @code{.drv}---these files are referred to as @dfn{derivation
3161 paths}. Derivations paths can be passed to the @code{build-derivations}
3162 procedure to perform the build actions they prescribe (@pxref{The
3165 The @code{(guix derivations)} module provides a representation of
3166 derivations as Scheme objects, along with procedures to create and
3167 otherwise manipulate derivations. The lowest-level primitive to create
3168 a derivation is the @code{derivation} procedure:
3170 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3171 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3172 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3173 [#:system (%current-system)] [#:references-graphs #f] @
3174 [#:allowed-references #f] [#:disallowed-references #f] @
3175 [#:leaked-env-vars #f] [#:local-build? #f] @
3176 [#:substitutable? #t]
3177 Build a derivation with the given arguments, and return the resulting
3178 @code{<derivation>} object.
3180 When @var{hash} and @var{hash-algo} are given, a
3181 @dfn{fixed-output derivation} is created---i.e., one whose result is
3182 known in advance, such as a file download. If, in addition,
3183 @var{recursive?} is true, then that fixed output may be an executable
3184 file or a directory and @var{hash} must be the hash of an archive
3185 containing this output.
3187 When @var{references-graphs} is true, it must be a list of file
3188 name/store path pairs. In that case, the reference graph of each store
3189 path is exported in the build environment in the corresponding file, in
3190 a simple text format.
3192 When @var{allowed-references} is true, it must be a list of store items
3193 or outputs that the derivation's output may refer to. Likewise,
3194 @var{disallowed-references}, if true, must be a list of things the
3195 outputs may @emph{not} refer to.
3197 When @var{leaked-env-vars} is true, it must be a list of strings
3198 denoting environment variables that are allowed to ``leak'' from the
3199 daemon's environment to the build environment. This is only applicable
3200 to fixed-output derivations---i.e., when @var{hash} is true. The main
3201 use is to allow variables such as @code{http_proxy} to be passed to
3202 derivations that download files.
3204 When @var{local-build?} is true, declare that the derivation is not a
3205 good candidate for offloading and should rather be built locally
3206 (@pxref{Daemon Offload Setup}). This is the case for small derivations
3207 where the costs of data transfers would outweigh the benefits.
3209 When @var{substitutable?} is false, declare that substitutes of the
3210 derivation's output should not be used (@pxref{Substitutes}). This is
3211 useful, for instance, when building packages that capture details of the
3212 host CPU instruction set.
3216 Here's an example with a shell script as its builder, assuming
3217 @var{store} is an open connection to the daemon, and @var{bash} points
3218 to a Bash executable in the store:
3221 (use-modules (guix utils)
3225 (let ((builder ; add the Bash script to the store
3226 (add-text-to-store store "my-builder.sh"
3227 "echo hello world > $out\n" '())))
3228 (derivation store "foo"
3229 bash `("-e" ,builder)
3230 #:inputs `((,bash) (,builder))
3231 #:env-vars '(("HOME" . "/homeless"))))
3232 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
3235 As can be guessed, this primitive is cumbersome to use directly. A
3236 better approach is to write build scripts in Scheme, of course! The
3237 best course of action for that is to write the build code as a
3238 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
3239 information, @pxref{G-Expressions}.
3241 Once upon a time, @code{gexp->derivation} did not exist and constructing
3242 derivations with build code written in Scheme was achieved with
3243 @code{build-expression->derivation}, documented below. This procedure
3244 is now deprecated in favor of the much nicer @code{gexp->derivation}.
3246 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
3247 @var{name} @var{exp} @
3248 [#:system (%current-system)] [#:inputs '()] @
3249 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3250 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3251 [#:references-graphs #f] [#:allowed-references #f] @
3252 [#:disallowed-references #f] @
3253 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3254 Return a derivation that executes Scheme expression @var{exp} as a
3255 builder for derivation @var{name}. @var{inputs} must be a list of
3256 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
3257 @code{"out"} is assumed. @var{modules} is a list of names of Guile
3258 modules from the current search path to be copied in the store,
3259 compiled, and made available in the load path during the execution of
3260 @var{exp}---e.g., @code{((guix build utils) (guix build
3261 gnu-build-system))}.
3263 @var{exp} is evaluated in an environment where @code{%outputs} is bound
3264 to a list of output/path pairs, and where @code{%build-inputs} is bound
3265 to a list of string/output-path pairs made from @var{inputs}.
3266 Optionally, @var{env-vars} is a list of string pairs specifying the name
3267 and value of environment variables visible to the builder. The builder
3268 terminates by passing the result of @var{exp} to @code{exit}; thus, when
3269 @var{exp} returns @code{#f}, the build is considered to have failed.
3271 @var{exp} is built using @var{guile-for-build} (a derivation). When
3272 @var{guile-for-build} is omitted or is @code{#f}, the value of the
3273 @code{%guile-for-build} fluid is used instead.
3275 See the @code{derivation} procedure for the meaning of
3276 @var{references-graphs}, @var{allowed-references},
3277 @var{disallowed-references}, @var{local-build?}, and
3278 @var{substitutable?}.
3282 Here's an example of a single-output derivation that creates a directory
3283 containing one file:
3286 (let ((builder '(let ((out (assoc-ref %outputs "out")))
3287 (mkdir out) ; create /gnu/store/@dots{}-goo
3288 (call-with-output-file (string-append out "/test")
3290 (display '(hello guix) p))))))
3291 (build-expression->derivation store "goo" builder))
3293 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
3297 @node The Store Monad
3298 @section The Store Monad
3302 The procedures that operate on the store described in the previous
3303 sections all take an open connection to the build daemon as their first
3304 argument. Although the underlying model is functional, they either have
3305 side effects or depend on the current state of the store.
3307 The former is inconvenient: the connection to the build daemon has to be
3308 carried around in all those functions, making it impossible to compose
3309 functions that do not take that parameter with functions that do. The
3310 latter can be problematic: since store operations have side effects
3311 and/or depend on external state, they have to be properly sequenced.
3313 @cindex monadic values
3314 @cindex monadic functions
3315 This is where the @code{(guix monads)} module comes in. This module
3316 provides a framework for working with @dfn{monads}, and a particularly
3317 useful monad for our uses, the @dfn{store monad}. Monads are a
3318 construct that allows two things: associating ``context'' with values
3319 (in our case, the context is the store), and building sequences of
3320 computations (here computations include accesses to the store). Values
3321 in a monad---values that carry this additional context---are called
3322 @dfn{monadic values}; procedures that return such values are called
3323 @dfn{monadic procedures}.
3325 Consider this ``normal'' procedure:
3328 (define (sh-symlink store)
3329 ;; Return a derivation that symlinks the 'bash' executable.
3330 (let* ((drv (package-derivation store bash))
3331 (out (derivation->output-path drv))
3332 (sh (string-append out "/bin/bash")))
3333 (build-expression->derivation store "sh"
3334 `(symlink ,sh %output))))
3337 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
3338 as a monadic function:
3341 (define (sh-symlink)
3342 ;; Same, but return a monadic value.
3343 (mlet %store-monad ((drv (package->derivation bash)))
3344 (gexp->derivation "sh"
3345 #~(symlink (string-append #$drv "/bin/bash")
3349 There are several things to note in the second version: the @code{store}
3350 parameter is now implicit and is ``threaded'' in the calls to the
3351 @code{package->derivation} and @code{gexp->derivation} monadic
3352 procedures, and the monadic value returned by @code{package->derivation}
3353 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
3355 As it turns out, the call to @code{package->derivation} can even be
3356 omitted since it will take place implicitly, as we will see later
3357 (@pxref{G-Expressions}):
3360 (define (sh-symlink)
3361 (gexp->derivation "sh"
3362 #~(symlink (string-append #$bash "/bin/bash")
3367 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
3368 @c for the funny quote.
3369 Calling the monadic @code{sh-symlink} has no effect. As someone once
3370 said, ``you exit a monad like you exit a building on fire: by running''.
3371 So, to exit the monad and get the desired effect, one must use
3372 @code{run-with-store}:
3375 (run-with-store (open-connection) (sh-symlink))
3376 @result{} /gnu/store/...-sh-symlink
3379 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
3380 new ``meta-commands'' to make it easier to deal with monadic procedures:
3381 @code{run-in-store}, and @code{enter-store-monad}. The former is used
3382 to ``run'' a single monadic value through the store:
3385 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
3386 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
3389 The latter enters a recursive REPL, where all the return values are
3390 automatically run through the store:
3393 scheme@@(guile-user)> ,enter-store-monad
3394 store-monad@@(guile-user) [1]> (package->derivation hello)
3395 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
3396 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
3397 $3 = "/gnu/store/@dots{}-foo"
3398 store-monad@@(guile-user) [1]> ,q
3399 scheme@@(guile-user)>
3403 Note that non-monadic values cannot be returned in the
3404 @code{store-monad} REPL.
3406 The main syntactic forms to deal with monads in general are provided by
3407 the @code{(guix monads)} module and are described below.
3409 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
3410 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
3414 @deffn {Scheme Syntax} return @var{val}
3415 Return a monadic value that encapsulates @var{val}.
3418 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
3419 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
3420 procedures @var{mproc}@dots{}@footnote{This operation is commonly
3421 referred to as ``bind'', but that name denotes an unrelated procedure in
3422 Guile. Thus we use this somewhat cryptic symbol inherited from the
3423 Haskell language.}. There can be one @var{mproc} or several of them, as
3428 (with-monad %state-monad
3430 (lambda (x) (return (+ 1 x)))
3431 (lambda (x) (return (* 2 x)))))
3435 @result{} some-state
3439 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
3441 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
3443 Bind the variables @var{var} to the monadic values @var{mval} in
3444 @var{body}. The form (@var{var} -> @var{val}) binds @var{var} to the
3445 ``normal'' value @var{val}, as per @code{let}.
3447 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
3448 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
3451 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
3452 Bind @var{mexp} and the following monadic expressions in sequence,
3453 returning the result of the last expression.
3455 This is akin to @code{mlet}, except that the return values of the
3456 monadic expressions are ignored. In that sense, it is analogous to
3457 @code{begin}, but applied to monadic expressions.
3461 The @code{(guix monads)} module provides the @dfn{state monad}, which
3462 allows an additional value---the state---to be @emph{threaded} through
3463 monadic procedure calls.
3465 @defvr {Scheme Variable} %state-monad
3466 The state monad. Procedures in the state monad can access and change
3467 the state that is threaded.
3469 Consider the example below. The @code{square} procedure returns a value
3470 in the state monad. It returns the square of its argument, but also
3471 increments the current state value:
3475 (mlet %state-monad ((count (current-state)))
3476 (mbegin %state-monad
3477 (set-current-state (+ 1 count))
3480 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
3485 When ``run'' through @var{%state-monad}, we obtain that additional state
3486 value, which is the number of @code{square} calls.
3489 @deffn {Monadic Procedure} current-state
3490 Return the current state as a monadic value.
3493 @deffn {Monadic Procedure} set-current-state @var{value}
3494 Set the current state to @var{value} and return the previous state as a
3498 @deffn {Monadic Procedure} state-push @var{value}
3499 Push @var{value} to the current state, which is assumed to be a list,
3500 and return the previous state as a monadic value.
3503 @deffn {Monadic Procedure} state-pop
3504 Pop a value from the current state and return it as a monadic value.
3505 The state is assumed to be a list.
3508 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
3509 Run monadic value @var{mval} starting with @var{state} as the initial
3510 state. Return two values: the resulting value, and the resulting state.
3513 The main interface to the store monad, provided by the @code{(guix
3514 store)} module, is as follows.
3516 @defvr {Scheme Variable} %store-monad
3517 The store monad---an alias for @var{%state-monad}.
3519 Values in the store monad encapsulate accesses to the store. When its
3520 effect is needed, a value of the store monad must be ``evaluated'' by
3521 passing it to the @code{run-with-store} procedure (see below.)
3524 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
3525 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
3526 open store connection.
3529 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
3530 Return as a monadic value the absolute file name in the store of the file
3531 containing @var{text}, a string. @var{references} is a list of store items that the
3532 resulting text file refers to; it defaults to the empty list.
3535 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
3536 [#:recursive? #t] [#:select? (const #t)]
3537 Return the name of @var{file} once interned in the store. Use
3538 @var{name} as its store name, or the basename of @var{file} if
3539 @var{name} is omitted.
3541 When @var{recursive?} is true, the contents of @var{file} are added
3542 recursively; if @var{file} designates a flat file and @var{recursive?}
3543 is true, its contents are added, and its permission bits are kept.
3545 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
3546 @var{stat})} for each directory entry, where @var{file} is the entry's
3547 absolute file name and @var{stat} is the result of @code{lstat}; exclude
3548 entries for which @var{select?} does not return true.
3550 The example below adds a file to the store, under two different names:
3553 (run-with-store (open-connection)
3554 (mlet %store-monad ((a (interned-file "README"))
3555 (b (interned-file "README" "LEGU-MIN")))
3556 (return (list a b))))
3558 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
3563 The @code{(guix packages)} module exports the following package-related
3566 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
3567 [#:system (%current-system)] [#:target #f] @
3570 value in the absolute file name of @var{file} within the @var{output}
3571 directory of @var{package}. When @var{file} is omitted, return the name
3572 of the @var{output} directory of @var{package}. When @var{target} is
3573 true, use it as a cross-compilation target triplet.
3576 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
3577 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
3578 @var{target} [@var{system}]
3579 Monadic version of @code{package-derivation} and
3580 @code{package-cross-derivation} (@pxref{Defining Packages}).
3585 @section G-Expressions
3587 @cindex G-expression
3588 @cindex build code quoting
3589 So we have ``derivations'', which represent a sequence of build actions
3590 to be performed to produce an item in the store (@pxref{Derivations}).
3591 These build actions are performed when asking the daemon to actually
3592 build the derivations; they are run by the daemon in a container
3593 (@pxref{Invoking guix-daemon}).
3595 @cindex strata of code
3596 It should come as no surprise that we like to write these build actions
3597 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
3598 code@footnote{The term @dfn{stratum} in this context was coined by
3599 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
3600 Kiselyov, who has written insightful
3601 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
3602 on this topic}, refers to this kind of code generation as
3603 @dfn{staging}.}: the ``host code''---code that defines packages, talks
3604 to the daemon, etc.---and the ``build code''---code that actually
3605 performs build actions, such as making directories, invoking
3606 @command{make}, etc.
3608 To describe a derivation and its build actions, one typically needs to
3609 embed build code inside host code. It boils down to manipulating build
3610 code as data, and the homoiconicity of Scheme---code has a direct
3611 representation as data---comes in handy for that. But we need more than
3612 the normal @code{quasiquote} mechanism in Scheme to construct build
3615 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
3616 S-expressions adapted to build expressions. G-expressions, or
3617 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
3618 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
3619 @code{#$}, and @code{#$@@}), which are comparable to
3620 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
3621 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
3622 GNU Guile Reference Manual}). However, there are major differences:
3626 Gexps are meant to be written to a file and run or manipulated by other
3630 When a high-level object such as a package or derivation is unquoted
3631 inside a gexp, the result is as if its output file name had been
3635 Gexps carry information about the packages or derivations they refer to,
3636 and these dependencies are automatically added as inputs to the build
3637 processes that use them.
3640 @cindex lowering, of high-level objects in gexps
3641 This mechanism is not limited to package and derivation
3642 objects: @dfn{compilers} able to ``lower'' other high-level objects to
3643 derivations or files in the store can be defined,
3644 such that these objects can also be inserted
3645 into gexps. For example, a useful type of high-level objects that can be
3646 inserted in a gexp is ``file-like objects'', which make it easy to
3647 add files to the store and to refer to them in
3648 derivations and such (see @code{local-file} and @code{plain-file}
3651 To illustrate the idea, here is an example of a gexp:
3658 (symlink (string-append #$coreutils "/bin/ls")
3662 This gexp can be passed to @code{gexp->derivation}; we obtain a
3663 derivation that builds a directory containing exactly one symlink to
3664 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
3667 (gexp->derivation "the-thing" build-exp)
3670 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
3671 substituted to the reference to the @var{coreutils} package in the
3672 actual build code, and @var{coreutils} is automatically made an input to
3673 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
3674 output)}) is replaced by a string containing the directory name of the
3675 output of the derivation.
3677 @cindex cross compilation
3678 In a cross-compilation context, it is useful to distinguish between
3679 references to the @emph{native} build of a package---that can run on the
3680 host---versus references to cross builds of a package. To that end, the
3681 @code{#+} plays the same role as @code{#$}, but is a reference to a
3682 native package build:
3685 (gexp->derivation "vi"
3688 (system* (string-append #+coreutils "/bin/ln")
3690 (string-append #$emacs "/bin/emacs")
3691 (string-append #$output "/bin/vi")))
3692 #:target "mips64el-linux")
3696 In the example above, the native build of @var{coreutils} is used, so
3697 that @command{ln} can actually run on the host; but then the
3698 cross-compiled build of @var{emacs} is referenced.
3700 @cindex imported modules, for gexps
3701 @findex with-imported-modules
3702 Another gexp feature is @dfn{imported modules}: sometimes you want to be
3703 able to use certain Guile modules from the ``host environment'' in the
3704 gexp, so those modules should be imported in the ``build environment''.
3705 The @code{with-imported-modules} form allows you to express that:
3708 (let ((build (with-imported-modules '((guix build utils))
3710 (use-modules (guix build utils))
3711 (mkdir-p (string-append #$output "/bin"))))))
3712 (gexp->derivation "empty-dir"
3715 (display "success!\n")
3720 In this example, the @code{(guix build utils)} module is automatically
3721 pulled into the isolated build environment of our gexp, such that
3722 @code{(use-modules (guix build utils))} works as expected.
3724 The syntactic form to construct gexps is summarized below.
3726 @deffn {Scheme Syntax} #~@var{exp}
3727 @deffnx {Scheme Syntax} (gexp @var{exp})
3728 Return a G-expression containing @var{exp}. @var{exp} may contain one
3729 or more of the following forms:
3733 @itemx (ungexp @var{obj})
3734 Introduce a reference to @var{obj}. @var{obj} may have one of the
3735 supported types, for example a package or a
3736 derivation, in which case the @code{ungexp} form is replaced by its
3737 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
3739 If @var{obj} is a list, it is traversed and references to supported
3740 objects are substituted similarly.
3742 If @var{obj} is another gexp, its contents are inserted and its
3743 dependencies are added to those of the containing gexp.
3745 If @var{obj} is another kind of object, it is inserted as is.
3747 @item #$@var{obj}:@var{output}
3748 @itemx (ungexp @var{obj} @var{output})
3749 This is like the form above, but referring explicitly to the
3750 @var{output} of @var{obj}---this is useful when @var{obj} produces
3751 multiple outputs (@pxref{Packages with Multiple Outputs}).
3754 @itemx #+@var{obj}:output
3755 @itemx (ungexp-native @var{obj})
3756 @itemx (ungexp-native @var{obj} @var{output})
3757 Same as @code{ungexp}, but produces a reference to the @emph{native}
3758 build of @var{obj} when used in a cross compilation context.
3760 @item #$output[:@var{output}]
3761 @itemx (ungexp output [@var{output}])
3762 Insert a reference to derivation output @var{output}, or to the main
3763 output when @var{output} is omitted.
3765 This only makes sense for gexps passed to @code{gexp->derivation}.
3768 @itemx (ungexp-splicing @var{lst})
3769 Like the above, but splices the contents of @var{lst} inside the
3773 @itemx (ungexp-native-splicing @var{lst})
3774 Like the above, but refers to native builds of the objects listed in
3779 G-expressions created by @code{gexp} or @code{#~} are run-time objects
3780 of the @code{gexp?} type (see below.)
3783 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
3784 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
3785 in their execution environment. @var{modules} must be a list of Guile
3786 module names, such as @code{'((guix build utils) (guix build gremlin))}.
3788 This form has @emph{lexical} scope: it has an effect on the gexps
3789 directly defined in @var{body}@dots{}, but not on those defined, say, in
3790 procedures called from @var{body}@dots{}.
3793 @deffn {Scheme Procedure} gexp? @var{obj}
3794 Return @code{#t} if @var{obj} is a G-expression.
3797 G-expressions are meant to be written to disk, either as code building
3798 some derivation, or as plain files in the store. The monadic procedures
3799 below allow you to do that (@pxref{The Store Monad}, for more
3800 information about monads.)
3802 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
3803 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
3804 [#:hash #f] [#:hash-algo #f] @
3805 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3806 [#:module-path @var{%load-path}] @
3807 [#:references-graphs #f] [#:allowed-references #f] @
3808 [#:disallowed-references #f] @
3809 [#:leaked-env-vars #f] @
3810 [#:script-name (string-append @var{name} "-builder")] @
3811 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3812 Return a derivation @var{name} that runs @var{exp} (a gexp) with
3813 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
3814 stored in a file called @var{script-name}. When @var{target} is true,
3815 it is used as the cross-compilation target triplet for packages referred
3818 @var{modules} is deprecated in favor of @code{with-imported-modules}.
3820 make @var{modules} available in the evaluation context of @var{exp};
3821 @var{modules} is a list of names of Guile modules searched in
3822 @var{module-path} to be copied in the store, compiled, and made available in
3823 the load path during the execution of @var{exp}---e.g., @code{((guix
3824 build utils) (guix build gnu-build-system))}.
3826 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
3829 When @var{references-graphs} is true, it must be a list of tuples of one of the
3833 (@var{file-name} @var{package})
3834 (@var{file-name} @var{package} @var{output})
3835 (@var{file-name} @var{derivation})
3836 (@var{file-name} @var{derivation} @var{output})
3837 (@var{file-name} @var{store-item})
3840 The right-hand-side of each element of @var{references-graphs} is automatically made
3841 an input of the build process of @var{exp}. In the build environment, each
3842 @var{file-name} contains the reference graph of the corresponding item, in a simple
3845 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
3846 In the latter case, the list denotes store items that the result is allowed to
3847 refer to. Any reference to another store item will lead to a build error.
3848 Similarly for @var{disallowed-references}, which can list items that must not be
3849 referenced by the outputs.
3851 The other arguments are as for @code{derivation} (@pxref{Derivations}).
3854 @cindex file-like objects
3855 The @code{local-file}, @code{plain-file}, @code{computed-file},
3856 @code{program-file}, and @code{scheme-file} procedures below return
3857 @dfn{file-like objects}. That is, when unquoted in a G-expression,
3858 these objects lead to a file in the store. Consider this G-expression:
3861 #~(system* (string-append #$glibc "/sbin/nscd") "-f"
3862 #$(local-file "/tmp/my-nscd.conf"))
3865 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
3866 to the store. Once expanded, for instance @i{via}
3867 @code{gexp->derivation}, the G-expression refers to that copy under
3868 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
3869 does not have any effect on what the G-expression does.
3870 @code{plain-file} can be used similarly; it differs in that the file
3871 content is directly passed as a string.
3873 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
3874 [#:recursive? #f] [#:select? (const #t)]
3875 Return an object representing local file @var{file} to add to the store; this
3876 object can be used in a gexp. If @var{file} is a relative file name, it is looked
3877 up relative to the source file where this form appears. @var{file} will be added to
3878 the store under @var{name}--by default the base name of @var{file}.
3880 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
3881 designates a flat file and @var{recursive?} is true, its contents are added, and its
3882 permission bits are kept.
3884 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
3885 @var{stat})} for each directory entry, where @var{file} is the entry's
3886 absolute file name and @var{stat} is the result of @code{lstat}; exclude
3887 entries for which @var{select?} does not return true.
3889 This is the declarative counterpart of the @code{interned-file} monadic
3890 procedure (@pxref{The Store Monad, @code{interned-file}}).
3893 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
3894 Return an object representing a text file called @var{name} with the given
3895 @var{content} (a string) to be added to the store.
3897 This is the declarative counterpart of @code{text-file}.
3900 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
3901 [#:modules '()] [#:options '(#:local-build? #t)]
3902 Return an object representing the store item @var{name}, a file or
3903 directory computed by @var{gexp}. @var{modules} specifies the set of
3904 modules visible in the execution context of @var{gexp}. @var{options}
3905 is a list of additional arguments to pass to @code{gexp->derivation}.
3907 This is the declarative counterpart of @code{gexp->derivation}.
3910 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
3911 Return an executable script @var{name} that runs @var{exp} using
3912 @var{guile} with @var{modules} in its search path.
3914 The example below builds a script that simply invokes the @command{ls}
3918 (use-modules (guix gexp) (gnu packages base))
3920 (gexp->script "list-files"
3921 #~(execl (string-append #$coreutils "/bin/ls")
3925 When ``running'' it through the store (@pxref{The Store Monad,
3926 @code{run-with-store}}), we obtain a derivation that produces an
3927 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
3930 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
3932 (execl (string-append "/gnu/store/@dots{}-coreutils-8.22"/bin/ls")
3937 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
3938 [#:modules '()] [#:guile #f]
3939 Return an object representing the executable store item @var{name} that
3940 runs @var{gexp}. @var{guile} is the Guile package used to execute that
3941 script, and @var{modules} is the list of modules visible to that script.
3943 This is the declarative counterpart of @code{gexp->script}.
3946 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
3947 [#:set-load-path? #t]
3948 Return a derivation that builds a file @var{name} containing @var{exp}.
3949 When @var{set-load-path?} is true, emit code in the resulting file to
3950 set @code{%load-path} and @code{%load-compiled-path} to honor
3951 @var{exp}'s imported modules.
3953 The resulting file holds references to all the dependencies of @var{exp}
3954 or a subset thereof.
3957 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
3958 Return an object representing the Scheme file @var{name} that contains
3961 This is the declarative counterpart of @code{gexp->file}.
3964 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
3965 Return as a monadic value a derivation that builds a text file
3966 containing all of @var{text}. @var{text} may list, in addition to
3967 strings, objects of any type that can be used in a gexp: packages,
3968 derivations, local file objects, etc. The resulting store file holds
3969 references to all these.
3971 This variant should be preferred over @code{text-file} anytime the file
3972 to create will reference items from the store. This is typically the
3973 case when building a configuration file that embeds store file names,
3977 (define (profile.sh)
3978 ;; Return the name of a shell script in the store that
3979 ;; initializes the 'PATH' environment variable.
3980 (text-file* "profile.sh"
3981 "export PATH=" coreutils "/bin:"
3982 grep "/bin:" sed "/bin\n"))
3985 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
3986 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
3987 preventing them from being garbage-collected during its lifetime.
3990 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
3991 Return an object representing store file @var{name} containing
3992 @var{text}. @var{text} is a sequence of strings and file-like objects,
3996 (mixed-text-file "profile"
3997 "export PATH=" coreutils "/bin:" grep "/bin")
4000 This is the declarative counterpart of @code{text-file*}.
4003 Of course, in addition to gexps embedded in ``host'' code, there are
4004 also modules containing build tools. To make it clear that they are
4005 meant to be used in the build stratum, these modules are kept in the
4006 @code{(guix build @dots{})} name space.
4008 @cindex lowering, of high-level objects in gexps
4009 Internally, high-level objects are @dfn{lowered}, using their compiler,
4010 to either derivations or store items. For instance, lowering a package
4011 yields a derivation, and lowering a @code{plain-file} yields a store
4012 item. This is achieved using the @code{lower-object} monadic procedure.
4014 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4016 Return as a value in @var{%store-monad} the derivation or store item
4017 corresponding to @var{obj} for @var{system}, cross-compiling for
4018 @var{target} if @var{target} is true. @var{obj} must be an object that
4019 has an associated gexp compiler, such as a @code{<package>}.
4023 @c *********************************************************************
4027 This section describes Guix command-line utilities. Some of them are
4028 primarily targeted at developers and users who write new package
4029 definitions, while others are more generally useful. They complement
4030 the Scheme programming interface of Guix in a convenient way.
4033 * Invoking guix build:: Building packages from the command line.
4034 * Invoking guix edit:: Editing package definitions.
4035 * Invoking guix download:: Downloading a file and printing its hash.
4036 * Invoking guix hash:: Computing the cryptographic hash of a file.
4037 * Invoking guix import:: Importing package definitions.
4038 * Invoking guix refresh:: Updating package definitions.
4039 * Invoking guix lint:: Finding errors in package definitions.
4040 * Invoking guix size:: Profiling disk usage.
4041 * Invoking guix graph:: Visualizing the graph of packages.
4042 * Invoking guix environment:: Setting up development environments.
4043 * Invoking guix publish:: Sharing substitutes.
4044 * Invoking guix challenge:: Challenging substitute servers.
4045 * Invoking guix container:: Process isolation.
4048 @node Invoking guix build
4049 @section Invoking @command{guix build}
4051 The @command{guix build} command builds packages or derivations and
4052 their dependencies, and prints the resulting store paths. Note that it
4053 does not modify the user's profile---this is the job of the
4054 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4055 it is mainly useful for distribution developers.
4057 The general syntax is:
4060 guix build @var{options} @var{package-or-derivation}@dots{}
4063 As an example, the following command builds the latest versions of Emacs
4064 and of Guile, displays their build logs, and finally displays the
4065 resulting directories:
4068 guix build emacs guile
4071 Similarly, the following command builds all the available packages:
4074 guix build --quiet --keep-going \
4075 `guix package -A | cut -f1,2 --output-delimiter=@@`
4078 @var{package-or-derivation} may be either the name of a package found in
4079 the software distribution such as @code{coreutils} or
4080 @code{coreutils-8.20}, or a derivation such as
4081 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4082 package with the corresponding name (and optionally version) is searched
4083 for among the GNU distribution modules (@pxref{Package Modules}).
4085 Alternatively, the @code{--expression} option may be used to specify a
4086 Scheme expression that evaluates to a package; this is useful when
4087 disambiguating among several same-named packages or package variants is
4090 There may be zero or more @var{options}. The available options are
4091 described in the subsections below.
4094 * Common Build Options:: Build options for most commands.
4095 * Package Transformation Options:: Creating variants of packages.
4096 * Additional Build Options:: Options specific to 'guix build'.
4099 @node Common Build Options
4100 @subsection Common Build Options
4102 A number of options that control the build process are common to
4103 @command{guix build} and other commands that can spawn builds, such as
4104 @command{guix package} or @command{guix archive}. These are the
4109 @item --load-path=@var{directory}
4110 @itemx -L @var{directory}
4111 Add @var{directory} to the front of the package module search path
4112 (@pxref{Package Modules}).
4114 This allows users to define their own packages and make them visible to
4115 the command-line tools.
4119 Keep the build tree of failed builds. Thus, if a build fails, its build
4120 tree is kept under @file{/tmp}, in a directory whose name is shown at
4121 the end of the build log. This is useful when debugging build issues.
4125 Keep going when some of the derivations fail to build; return only once
4126 all the builds have either completed or failed.
4128 The default behavior is to stop as soon as one of the specified
4129 derivations has failed.
4133 Do not build the derivations.
4136 When substituting a pre-built binary fails, fall back to building
4139 @item --substitute-urls=@var{urls}
4140 @anchor{client-substitute-urls}
4141 Consider @var{urls} the whitespace-separated list of substitute source
4142 URLs, overriding the default list of URLs of @command{guix-daemon}
4143 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
4145 This means that substitutes may be downloaded from @var{urls}, provided
4146 they are signed by a key authorized by the system administrator
4147 (@pxref{Substitutes}).
4149 When @var{urls} is the empty string, substitutes are effectively
4152 @item --no-substitutes
4153 Do not use substitutes for build products. That is, always build things
4154 locally instead of allowing downloads of pre-built binaries
4155 (@pxref{Substitutes}).
4158 Do not ``graft'' packages. In practice, this means that package updates
4159 available as grafts are not applied. @xref{Security Updates}, for more
4160 information on grafts.
4162 @item --rounds=@var{n}
4163 Build each derivation @var{n} times in a row, and raise an error if
4164 consecutive build results are not bit-for-bit identical.
4166 This is a useful way to detect non-deterministic builds processes.
4167 Non-deterministic build processes are a problem because they make it
4168 practically impossible for users to @emph{verify} whether third-party
4169 binaries are genuine. @xref{Invoking guix challenge}, for more.
4171 Note that, currently, the differing build results are not kept around,
4172 so you will have to manually investigate in case of an error---e.g., by
4173 stashing one of the build results with @code{guix archive --export}
4174 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
4177 @item --no-build-hook
4178 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
4179 (@pxref{Daemon Offload Setup}). That is, always build things locally
4180 instead of offloading builds to remote machines.
4182 @item --max-silent-time=@var{seconds}
4183 When the build or substitution process remains silent for more than
4184 @var{seconds}, terminate it and report a build failure.
4186 @item --timeout=@var{seconds}
4187 Likewise, when the build or substitution process lasts for more than
4188 @var{seconds}, terminate it and report a build failure.
4190 By default there is no timeout. This behavior can be restored with
4193 @item --verbosity=@var{level}
4194 Use the given verbosity level. @var{level} must be an integer between 0
4195 and 5; higher means more verbose output. Setting a level of 4 or more
4196 may be helpful when debugging setup issues with the build daemon.
4198 @item --cores=@var{n}
4200 Allow the use of up to @var{n} CPU cores for the build. The special
4201 value @code{0} means to use as many CPU cores as available.
4203 @item --max-jobs=@var{n}
4205 Allow at most @var{n} build jobs in parallel. @xref{Invoking
4206 guix-daemon, @code{--max-jobs}}, for details about this option and the
4207 equivalent @command{guix-daemon} option.
4211 Behind the scenes, @command{guix build} is essentially an interface to
4212 the @code{package-derivation} procedure of the @code{(guix packages)}
4213 module, and to the @code{build-derivations} procedure of the @code{(guix
4214 derivations)} module.
4216 In addition to options explicitly passed on the command line,
4217 @command{guix build} and other @command{guix} commands that support
4218 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
4220 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
4221 Users can define this variable to a list of command line options that
4222 will automatically be used by @command{guix build} and other
4223 @command{guix} commands that can perform builds, as in the example
4227 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
4230 These options are parsed independently, and the result is appended to
4231 the parsed command-line options.
4235 @node Package Transformation Options
4236 @subsection Package Transformation Options
4238 @cindex package variants
4239 Another set of command-line options supported by @command{guix build}
4240 and also @command{guix package} are @dfn{package transformation
4241 options}. These are options that make it possible to define @dfn{package
4242 variants}---for instance, packages built from different source code.
4243 This is a convenient way to create customized packages on the fly
4244 without having to type in the definitions of package variants
4245 (@pxref{Defining Packages}).
4249 @item --with-source=@var{source}
4250 Use @var{source} as the source of the corresponding package.
4251 @var{source} must be a file name or a URL, as for @command{guix
4252 download} (@pxref{Invoking guix download}).
4254 The ``corresponding package'' is taken to be the one specified on the
4255 command line the name of which matches the base of @var{source}---e.g.,
4256 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
4257 package is @code{guile}. Likewise, the version string is inferred from
4258 @var{source}; in the previous example, it is @code{2.0.10}.
4260 This option allows users to try out versions of packages other than the
4261 one provided by the distribution. The example below downloads
4262 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
4263 the @code{ed} package:
4266 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
4269 As a developer, @code{--with-source} makes it easy to test release
4273 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
4276 @dots{} or to build from a checkout in a pristine environment:
4279 $ git clone git://git.sv.gnu.org/guix.git
4280 $ guix build guix --with-source=./guix
4283 @item --with-input=@var{package}=@var{replacement}
4284 Replace dependency on @var{package} by a dependency on
4285 @var{replacement}. @var{package} must be a package name, and
4286 @var{replacement} must be a package specification such as @code{guile}
4287 or @code{guile@@1.8}.
4289 For instance, the following command builds Guix, but replaces its
4290 dependency on the current stable version of Guile with a dependency on
4291 the development version of Guile, @code{guile-next}:
4294 guix build --with-input=guile=guile-next guix
4297 This is a recursive, deep replacement. So in this example, both
4298 @code{guix} and its dependency @code{guile-json} (which also depends on
4299 @code{guile}) get rebuilt against @code{guile-next}.
4301 However, implicit inputs are left unchanged.
4304 @node Additional Build Options
4305 @subsection Additional Build Options
4307 The command-line options presented below are specific to @command{guix
4314 Build quietly, without displaying the build log. Upon completion, the
4315 build log is kept in @file{/var} (or similar) and can always be
4316 retrieved using the @option{--log-file} option.
4318 @item --file=@var{file}
4319 @itemx -f @var{file}
4321 Build the package or derivation that the code within @var{file}
4324 As an example, @var{file} might contain a package definition like this
4325 (@pxref{Defining Packages}):
4328 @verbatiminclude package-hello.scm
4331 @item --expression=@var{expr}
4332 @itemx -e @var{expr}
4333 Build the package or derivation @var{expr} evaluates to.
4335 For example, @var{expr} may be @code{(@@ (gnu packages guile)
4336 guile-1.8)}, which unambiguously designates this specific variant of
4337 version 1.8 of Guile.
4339 Alternatively, @var{expr} may be a G-expression, in which case it is used
4340 as a build program passed to @code{gexp->derivation}
4341 (@pxref{G-Expressions}).
4343 Lastly, @var{expr} may refer to a zero-argument monadic procedure
4344 (@pxref{The Store Monad}). The procedure must return a derivation as a
4345 monadic value, which is then passed through @code{run-with-store}.
4349 Build the source derivations of the packages, rather than the packages
4352 For instance, @code{guix build -S gcc} returns something like
4353 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
4356 The returned source tarball is the result of applying any patches and
4357 code snippets specified in the package @code{origin} (@pxref{Defining
4361 Fetch and return the source of @var{package-or-derivation} and all their
4362 dependencies, recursively. This is a handy way to obtain a local copy
4363 of all the source code needed to build @var{packages}, allowing you to
4364 eventually build them even without network access. It is an extension
4365 of the @code{--source} option and can accept one of the following
4366 optional argument values:
4370 This value causes the @code{--sources} option to behave in the same way
4371 as the @code{--source} option.
4374 Build the source derivations of all packages, including any source that
4375 might be listed as @code{inputs}. This is the default value.
4378 $ guix build --sources tzdata
4379 The following derivations will be built:
4380 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
4381 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
4385 Build the source derivations of all packages, as well of all transitive
4386 inputs to the packages. This can be used e.g. to
4387 prefetch package source for later offline building.
4390 $ guix build --sources=transitive tzdata
4391 The following derivations will be built:
4392 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
4393 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
4394 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
4395 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
4396 /gnu/store/@dots{}-make-4.1.tar.xz.drv
4397 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
4403 @item --system=@var{system}
4404 @itemx -s @var{system}
4405 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
4406 the system type of the build host.
4408 An example use of this is on Linux-based systems, which can emulate
4409 different personalities. For instance, passing
4410 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
4411 to build packages in a complete 32-bit environment.
4413 @item --target=@var{triplet}
4414 @cindex cross-compilation
4415 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
4416 as @code{"mips64el-linux-gnu"} (@pxref{Configuration Names, GNU
4417 configuration triplets,, configure, GNU Configure and Build System}).
4419 @anchor{build-check}
4421 @cindex determinism, checking
4422 @cindex reproducibility, checking
4423 Rebuild @var{package-or-derivation}, which are already available in the
4424 store, and raise an error if the build results are not bit-for-bit
4427 This mechanism allows you to check whether previously installed
4428 substitutes are genuine (@pxref{Substitutes}), or whether the build result
4429 of a package is deterministic. @xref{Invoking guix challenge}, for more
4430 background information and tools.
4432 When used in conjunction with @option{--keep-failed}, the differing
4433 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
4434 This makes it easy to look for differences between the two results.
4438 Return the derivation paths, not the output paths, of the given
4441 @item --root=@var{file}
4442 @itemx -r @var{file}
4443 Make @var{file} a symlink to the result, and register it as a garbage
4447 Return the build log file names or URLs for the given
4448 @var{package-or-derivation}, or raise an error if build logs are
4451 This works regardless of how packages or derivations are specified. For
4452 instance, the following invocations are equivalent:
4455 guix build --log-file `guix build -d guile`
4456 guix build --log-file `guix build guile`
4457 guix build --log-file guile
4458 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
4461 If a log is unavailable locally, and unless @code{--no-substitutes} is
4462 passed, the command looks for a corresponding log on one of the
4463 substitute servers (as specified with @code{--substitute-urls}.)
4465 So for instance, imagine you want to see the build log of GDB on MIPS,
4466 but you are actually on an @code{x86_64} machine:
4469 $ guix build --log-file gdb -s mips64el-linux
4470 https://hydra.gnu.org/log/@dots{}-gdb-7.10
4473 You can freely access a huge library of build logs!
4477 @node Invoking guix edit
4478 @section Invoking @command{guix edit}
4480 @cindex package definition, editing
4481 So many packages, so many source files! The @command{guix edit} command
4482 facilitates the life of packagers by pointing their editor at the source
4483 file containing the definition of the specified packages. For instance:
4486 guix edit gcc@@4.9 vim
4490 launches the program specified in the @code{VISUAL} or in the
4491 @code{EDITOR} environment variable to edit the recipe of GCC@tie{}4.9.3
4494 If you are using Emacs, note that the Emacs user interface provides the
4495 @kbd{M-x guix-edit} command and a similar functionality in the ``package
4496 info'' and ``package list'' buffers created by the @kbd{M-x
4497 guix-search-by-name} and similar commands (@pxref{Emacs Commands}).
4500 @node Invoking guix download
4501 @section Invoking @command{guix download}
4503 When writing a package definition, developers typically need to download
4504 a source tarball, compute its SHA256 hash, and write that
4505 hash in the package definition (@pxref{Defining Packages}). The
4506 @command{guix download} tool helps with this task: it downloads a file
4507 from the given URI, adds it to the store, and prints both its file name
4508 in the store and its SHA256 hash.
4510 The fact that the downloaded file is added to the store saves bandwidth:
4511 when the developer eventually tries to build the newly defined package
4512 with @command{guix build}, the source tarball will not have to be
4513 downloaded again because it is already in the store. It is also a
4514 convenient way to temporarily stash files, which may be deleted
4515 eventually (@pxref{Invoking guix gc}).
4517 The @command{guix download} command supports the same URIs as used in
4518 package definitions. In particular, it supports @code{mirror://} URIs.
4519 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
4520 Guile bindings for GnuTLS are available in the user's environment; when
4521 they are not available, an error is raised. @xref{Guile Preparations,
4522 how to install the GnuTLS bindings for Guile,, gnutls-guile,
4523 GnuTLS-Guile}, for more information.
4525 The following option is available:
4528 @item --format=@var{fmt}
4530 Write the hash in the format specified by @var{fmt}. For more
4531 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
4534 @node Invoking guix hash
4535 @section Invoking @command{guix hash}
4537 The @command{guix hash} command computes the SHA256 hash of a file.
4538 It is primarily a convenience tool for anyone contributing to the
4539 distribution: it computes the cryptographic hash of a file, which can be
4540 used in the definition of a package (@pxref{Defining Packages}).
4542 The general syntax is:
4545 guix hash @var{option} @var{file}
4548 @command{guix hash} has the following option:
4552 @item --format=@var{fmt}
4554 Write the hash in the format specified by @var{fmt}.
4556 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
4557 (@code{hex} and @code{hexadecimal} can be used as well).
4559 If the @option{--format} option is not specified, @command{guix hash}
4560 will output the hash in @code{nix-base32}. This representation is used
4561 in the definitions of packages.
4565 Compute the hash on @var{file} recursively.
4567 In this case, the hash is computed on an archive containing @var{file},
4568 including its children if it is a directory. Some of the metadata of
4569 @var{file} is part of the archive; for instance, when @var{file} is a
4570 regular file, the hash is different depending on whether @var{file} is
4571 executable or not. Metadata such as time stamps has no impact on the
4572 hash (@pxref{Invoking guix archive}).
4573 @c FIXME: Replace xref above with xref to an ``Archive'' section when
4578 @node Invoking guix import
4579 @section Invoking @command{guix import}
4581 @cindex importing packages
4582 @cindex package import
4583 @cindex package conversion
4584 The @command{guix import} command is useful for people who would like to
4585 add a package to the distribution with as little work as
4586 possible---a legitimate demand. The command knows of a few
4587 repositories from which it can ``import'' package metadata. The result
4588 is a package definition, or a template thereof, in the format we know
4589 (@pxref{Defining Packages}).
4591 The general syntax is:
4594 guix import @var{importer} @var{options}@dots{}
4597 @var{importer} specifies the source from which to import package
4598 metadata, and @var{options} specifies a package identifier and other
4599 options specific to @var{importer}. Currently, the available
4604 Import metadata for the given GNU package. This provides a template
4605 for the latest version of that GNU package, including the hash of its
4606 source tarball, and its canonical synopsis and description.
4608 Additional information such as the package dependencies and its
4609 license needs to be figured out manually.
4611 For example, the following command returns a package definition for
4615 guix import gnu hello
4618 Specific command-line options are:
4621 @item --key-download=@var{policy}
4622 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
4623 keys when verifying the package signature. @xref{Invoking guix
4624 refresh, @code{--key-download}}.
4629 Import metadata from the @uref{https://pypi.python.org/, Python Package
4630 Index}@footnote{This functionality requires Guile-JSON to be installed.
4631 @xref{Requirements}.}. Information is taken from the JSON-formatted
4632 description available at @code{pypi.python.org} and usually includes all
4633 the relevant information, including package dependencies. For maximum
4634 efficiency, it is recommended to install the @command{unzip} utility, so
4635 that the importer can unzip Python wheels and gather data from them.
4637 The command below imports metadata for the @code{itsdangerous} Python
4641 guix import pypi itsdangerous
4646 Import metadata from @uref{https://rubygems.org/,
4647 RubyGems}@footnote{This functionality requires Guile-JSON to be
4648 installed. @xref{Requirements}.}. Information is taken from the
4649 JSON-formatted description available at @code{rubygems.org} and includes
4650 most relevant information, including runtime dependencies. There are
4651 some caveats, however. The metadata doesn't distinguish between
4652 synopses and descriptions, so the same string is used for both fields.
4653 Additionally, the details of non-Ruby dependencies required to build
4654 native extensions is unavailable and left as an exercise to the
4657 The command below imports metadata for the @code{rails} Ruby package:
4660 guix import gem rails
4665 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
4666 functionality requires Guile-JSON to be installed.
4667 @xref{Requirements}.}.
4668 Information is taken from the JSON-formatted metadata provided through
4669 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
4670 relevant information, such as module dependencies. License information
4671 should be checked closely. If Perl is available in the store, then the
4672 @code{corelist} utility will be used to filter core modules out of the
4673 list of dependencies.
4675 The command command below imports metadata for the @code{Acme::Boolean}
4679 guix import cpan Acme::Boolean
4684 @cindex Bioconductor
4685 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
4686 central repository for the @uref{http://r-project.org, GNU@tie{}R
4687 statistical and graphical environment}.
4689 Information is extracted from the @code{DESCRIPTION} file of the package.
4691 The command command below imports metadata for the @code{Cairo}
4695 guix import cran Cairo
4698 When @code{--archive=bioconductor} is added, metadata is imported from
4699 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
4700 packages for for the analysis and comprehension of high-throughput
4701 genomic data in bioinformatics.
4703 Information is extracted from the @code{DESCRIPTION} file of a package
4704 published on the web interface of the Bioconductor SVN repository.
4706 The command below imports metadata for the @code{GenomicRanges}
4710 guix import cran --archive=bioconductor GenomicRanges
4714 Import metadata from a local copy of the source of the
4715 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
4716 relies on the @command{nix-instantiate} command of
4717 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
4718 typically written in a mixture of Nix-language and Bash code. This
4719 command only imports the high-level package structure that is written in
4720 the Nix language. It normally includes all the basic fields of a
4723 When importing a GNU package, the synopsis and descriptions are replaced
4724 by their canonical upstream variant.
4726 Usually, you will first need to do:
4729 export NIX_REMOTE=daemon
4733 so that @command{nix-instantiate} does not try to open the Nix database.
4735 As an example, the command below imports the package definition of
4736 LibreOffice (more precisely, it imports the definition of the package
4737 bound to the @code{libreoffice} top-level attribute):
4740 guix import nix ~/path/to/nixpkgs libreoffice
4745 Import metadata from the Haskell community's central package archive
4746 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
4747 Cabal files and includes all the relevant information, including package
4750 Specific command-line options are:
4755 Read a Cabal file from standard input.
4756 @item --no-test-dependencies
4758 Do not include dependencies required only by the test suites.
4759 @item --cabal-environment=@var{alist}
4760 @itemx -e @var{alist}
4761 @var{alist} is a Scheme alist defining the environment in which the
4762 Cabal conditionals are evaluated. The accepted keys are: @code{os},
4763 @code{arch}, @code{impl} and a string representing the name of a flag.
4764 The value associated with a flag has to be either the symbol
4765 @code{true} or @code{false}. The value associated with other keys
4766 has to conform to the Cabal file format definition. The default value
4767 associated with the keys @code{os}, @code{arch} and @code{impl} is
4768 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
4771 The command below imports metadata for the latest version of the
4772 @code{HTTP} Haskell package without including test dependencies and
4773 specifying the value of the flag @samp{network-uri} as @code{false}:
4776 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
4779 A specific package version may optionally be specified by following the
4780 package name by an at-sign and a version number as in the following example:
4783 guix import hackage mtl@@2.1.3.1
4788 Import metadata from an Emacs Lisp Package Archive (ELPA) package
4789 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
4791 Specific command-line options are:
4794 @item --archive=@var{repo}
4795 @itemx -a @var{repo}
4796 @var{repo} identifies the archive repository from which to retrieve the
4797 information. Currently the supported repositories and their identifiers
4801 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
4802 identifier. This is the default.
4805 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
4806 @code{melpa-stable} identifier.
4809 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
4815 The structure of the @command{guix import} code is modular. It would be
4816 useful to have more importers for other package formats, and your help
4817 is welcome here (@pxref{Contributing}).
4819 @node Invoking guix refresh
4820 @section Invoking @command{guix refresh}
4822 The primary audience of the @command{guix refresh} command is developers
4823 of the GNU software distribution. By default, it reports any packages
4824 provided by the distribution that are outdated compared to the latest
4825 upstream version, like this:
4829 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
4830 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
4833 It does so by browsing the FTP directory of each package and determining
4834 the highest version number of the source tarballs therein. The command
4835 knows how to update specific types of packages: GNU packages, ELPA
4836 packages, etc.---see the documentation for @option{--type} below. The
4837 are many packages, though, for which it lacks a method to determine
4838 whether a new upstream release is available. However, the mechanism is
4839 extensible, so feel free to get in touch with us to add a new method!
4841 When passed @code{--update}, it modifies distribution source files to
4842 update the version numbers and source tarball hashes of those package
4843 recipes (@pxref{Defining Packages}). This is achieved by downloading
4844 each package's latest source tarball and its associated OpenPGP
4845 signature, authenticating the downloaded tarball against its signature
4846 using @command{gpg}, and finally computing its hash. When the public
4847 key used to sign the tarball is missing from the user's keyring, an
4848 attempt is made to automatically retrieve it from a public key server;
4849 when this is successful, the key is added to the user's keyring; otherwise,
4850 @command{guix refresh} reports an error.
4852 The following options are supported:
4856 @item --expression=@var{expr}
4857 @itemx -e @var{expr}
4858 Consider the package @var{expr} evaluates to.
4860 This is useful to precisely refer to a package, as in this example:
4863 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
4866 This command lists the dependents of the ``final'' libc (essentially all
4871 Update distribution source files (package recipes) in place. This is
4872 usually run from a checkout of the Guix source tree (@pxref{Running
4873 Guix Before It Is Installed}):
4876 $ ./pre-inst-env guix refresh -s non-core
4879 @xref{Defining Packages}, for more information on package definitions.
4881 @item --select=[@var{subset}]
4882 @itemx -s @var{subset}
4883 Select all the packages in @var{subset}, one of @code{core} or
4886 The @code{core} subset refers to all the packages at the core of the
4887 distribution---i.e., packages that are used to build ``everything
4888 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
4889 changing one of these packages in the distribution entails a rebuild of
4890 all the others. Thus, such updates are an inconvenience to users in
4891 terms of build time or bandwidth used to achieve the upgrade.
4893 The @code{non-core} subset refers to the remaining packages. It is
4894 typically useful in cases where an update of the core packages would be
4897 @item --type=@var{updater}
4898 @itemx -t @var{updater}
4899 Select only packages handled by @var{updater} (may be a comma-separated
4900 list of updaters). Currently, @var{updater} may be one of:
4904 the updater for GNU packages;
4906 the updater for GNOME packages;
4908 the updater for X.org packages;
4910 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
4912 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
4914 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
4916 the updater for @uref{https://pypi.python.org, PyPI} packages.
4918 the updater for @uref{https://rubygems.org, RubyGems} packages.
4920 the updater for @uref{https://github.com, GitHub} packages.
4922 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
4925 For instance, the following command only checks for updates of Emacs
4926 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
4929 $ guix refresh --type=elpa,cran
4930 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
4931 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
4936 In addition, @command{guix refresh} can be passed one or more package
4937 names, as in this example:
4940 $ ./pre-inst-env guix refresh -u emacs idutils gcc-4.8.4
4944 The command above specifically updates the @code{emacs} and
4945 @code{idutils} packages. The @code{--select} option would have no
4946 effect in this case.
4948 When considering whether to upgrade a package, it is sometimes
4949 convenient to know which packages would be affected by the upgrade and
4950 should be checked for compatibility. For this the following option may
4951 be used when passing @command{guix refresh} one or more package names:
4955 @item --list-updaters
4957 List available updaters and exit (see @option{--type} above.)
4959 @item --list-dependent
4961 List top-level dependent packages that would need to be rebuilt as a
4962 result of upgrading one or more packages.
4966 Be aware that the @code{--list-dependent} option only
4967 @emph{approximates} the rebuilds that would be required as a result of
4968 an upgrade. More rebuilds might be required under some circumstances.
4971 $ guix refresh --list-dependent flex
4972 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
4973 hop-2.4.0 geiser-0.4 notmuch-0.18 mu-0.9.9.5 cflow-1.4 idutils-4.6 @dots{}
4976 The command above lists a set of packages that could be built to check
4977 for compatibility with an upgraded @code{flex} package.
4979 The following options can be used to customize GnuPG operation:
4983 @item --gpg=@var{command}
4984 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
4985 for in @code{$PATH}.
4987 @item --key-download=@var{policy}
4988 Handle missing OpenPGP keys according to @var{policy}, which may be one
4993 Always download missing OpenPGP keys from the key server, and add them
4994 to the user's GnuPG keyring.
4997 Never try to download missing OpenPGP keys. Instead just bail out.
5000 When a package signed with an unknown OpenPGP key is encountered, ask
5001 the user whether to download it or not. This is the default behavior.
5004 @item --key-server=@var{host}
5005 Use @var{host} as the OpenPGP key server when importing a public key.
5009 The @code{github} updater uses the
5010 @uref{https://developer.github.com/v3/, GitHub API} to query for new
5011 releases. When used repeatedly e.g. when refreshing all packages,
5012 GitHub will eventually refuse to answer any further API requests. By
5013 default 60 API requests per hour are allowed, and a full refresh on all
5014 GitHub packages in Guix requires more than this. Authentication with
5015 GitHub through the use of an API token alleviates these limits. To use
5016 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
5017 token procured from @uref{https://github.com/settings/tokens} or
5021 @node Invoking guix lint
5022 @section Invoking @command{guix lint}
5023 The @command{guix lint} command is meant to help package developers avoid
5024 common errors and use a consistent style. It runs a number of checks on
5025 a given set of packages in order to find common mistakes in their
5026 definitions. Available @dfn{checkers} include (see
5027 @code{--list-checkers} for a complete list):
5032 Validate certain typographical and stylistic rules about package
5033 descriptions and synopses.
5035 @item inputs-should-be-native
5036 Identify inputs that should most likely be native inputs.
5040 @itemx source-file-name
5041 Probe @code{home-page} and @code{source} URLs and report those that are
5042 invalid. Check that the source file name is meaningful, e.g. is not
5043 just a version number or ``git-checkout'', without a declared
5044 @code{file-name} (@pxref{origin Reference}).
5047 @cindex security vulnerabilities
5048 @cindex CVE, Common Vulnerabilities and Exposures
5049 Report known vulnerabilities found in the Common Vulnerabilities and
5050 Exposures (CVE) databases of the current and past year
5051 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
5054 To view information about a particular vulnerability, visit pages such as:
5058 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
5060 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
5064 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
5065 @code{CVE-2015-7554}.
5067 Package developers can specify in package recipes the
5068 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
5069 name and version of the package when they differ from the name that Guix
5070 uses, as in this example:
5076 ;; CPE calls this package "grub2".
5077 (properties '((cpe-name . "grub2"))))
5081 Warn about obvious source code formatting issues: trailing white space,
5082 use of tabulations, etc.
5085 The general syntax is:
5088 guix lint @var{options} @var{package}@dots{}
5091 If no package is given on the command line, then all packages are checked.
5092 The @var{options} may be zero or more of the following:
5095 @item --list-checkers
5097 List and describe all the available checkers that will be run on packages
5102 Only enable the checkers specified in a comma-separated list using the
5103 names returned by @code{--list-checkers}.
5107 @node Invoking guix size
5108 @section Invoking @command{guix size}
5110 The @command{guix size} command helps package developers profile the
5111 disk usage of packages. It is easy to overlook the impact of an
5112 additional dependency added to a package, or the impact of using a
5113 single output for a package that could easily be split (@pxref{Packages
5114 with Multiple Outputs}). Such are the typical issues that
5115 @command{guix size} can highlight.
5117 The command can be passed a package specification such as @code{gcc-4.8}
5118 or @code{guile:debug}, or a file name in the store. Consider this
5122 $ guix size coreutils
5123 store item total self
5124 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
5125 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
5126 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
5127 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
5128 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
5129 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
5133 The store items listed here constitute the @dfn{transitive closure} of
5134 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
5135 would be returned by:
5138 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
5141 Here the output shows three columns next to store items. The first column,
5142 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
5143 the store item---that is, its own size plus the size of all its
5144 dependencies. The next column, labeled ``self'', shows the size of the
5145 item itself. The last column shows the ratio of the size of the item
5146 itself to the space occupied by all the items listed here.
5148 In this example, we see that the closure of Coreutils weighs in at
5149 70@tie{}MiB, half of which is taken by libc. (That libc represents a
5150 large fraction of the closure is not a problem @i{per se} because it is
5151 always available on the system anyway.)
5153 When the package passed to @command{guix size} is available in the
5154 store, @command{guix size} queries the daemon to determine its
5155 dependencies, and measures its size in the store, similar to @command{du
5156 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
5159 When the given package is @emph{not} in the store, @command{guix size}
5160 reports information based on the available substitutes
5161 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
5162 store items that are not even on disk, only available remotely.
5164 You can also specify several package names:
5167 $ guix size coreutils grep sed bash
5168 store item total self
5169 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
5170 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
5171 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
5172 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
5178 In this example we see that the combination of the four packages takes
5179 102.3@tie{}MiB in total, which is much less than the sum of each closure
5180 since they have a lot of dependencies in common.
5182 The available options are:
5186 @item --substitute-urls=@var{urls}
5187 Use substitute information from @var{urls}.
5188 @xref{client-substitute-urls, the same option for @code{guix build}}.
5190 @item --map-file=@var{file}
5191 Write a graphical map of disk usage in PNG format to @var{file}.
5193 For the example above, the map looks like this:
5195 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
5196 produced by @command{guix size}}
5198 This option requires that
5199 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
5200 installed and visible in Guile's module search path. When that is not
5201 the case, @command{guix size} fails as it tries to load it.
5203 @item --system=@var{system}
5204 @itemx -s @var{system}
5205 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
5209 @node Invoking guix graph
5210 @section Invoking @command{guix graph}
5213 Packages and their dependencies form a @dfn{graph}, specifically a
5214 directed acyclic graph (DAG). It can quickly become difficult to have a
5215 mental model of the package DAG, so the @command{guix graph} command
5216 provides a visual representation of the DAG. @command{guix graph}
5217 emits a DAG representation in the input format of
5218 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
5219 directly to the @command{dot} command of Graphviz. The general
5223 guix graph @var{options} @var{package}@dots{}
5226 For example, the following command generates a PDF file representing the
5227 package DAG for the GNU@tie{}Core Utilities, showing its build-time
5231 guix graph coreutils | dot -Tpdf > dag.pdf
5234 The output looks like this:
5236 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
5238 Nice little graph, no?
5240 But there is more than one graph! The one above is concise: it is the
5241 graph of package objects, omitting implicit inputs such as GCC, libc,
5242 grep, etc. It is often useful to have such a concise graph, but
5243 sometimes one may want to see more details. @command{guix graph} supports
5244 several types of graphs, allowing you to choose the level of detail:
5248 This is the default type used in the example above. It shows the DAG of
5249 package objects, excluding implicit dependencies. It is concise, but
5250 filters out many details.
5253 This is the package DAG, @emph{including} implicit inputs.
5255 For instance, the following command:
5258 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
5261 ... yields this bigger graph:
5263 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
5265 At the bottom of the graph, we see all the implicit inputs of
5266 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
5268 Now, note that the dependencies of these implicit inputs---that is, the
5269 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
5270 here, for conciseness.
5273 Similar to @code{bag-emerged}, but this time including all the bootstrap
5276 @item bag-with-origins
5277 Similar to @code{bag}, but also showing origins and their dependencies.
5280 This is the most detailed representation: It shows the DAG of
5281 derivations (@pxref{Derivations}) and plain store items. Compared to
5282 the above representation, many additional nodes are visible, including
5283 build scripts, patches, Guile modules, etc.
5285 For this type of graph, it is also possible to pass a @file{.drv} file
5286 name instead of a package name, as in:
5289 guix graph -t derivation `guix system build -d my-config.scm`
5293 All the types above correspond to @emph{build-time dependencies}. The
5294 following graph type represents the @emph{run-time dependencies}:
5298 This is the graph of @dfn{references} of a package output, as returned
5299 by @command{guix gc --references} (@pxref{Invoking guix gc}).
5301 If the given package output is not available in the store, @command{guix
5302 graph} attempts to obtain dependency information from substitutes.
5304 Here you can also pass a store file name instead of a package name. For
5305 example, the command below produces the reference graph of your profile
5306 (which can be big!):
5309 guix graph -t references `readlink -f ~/.guix-profile`
5313 The available options are the following:
5316 @item --type=@var{type}
5317 @itemx -t @var{type}
5318 Produce a graph output of @var{type}, where @var{type} must be one of
5319 the values listed above.
5322 List the supported graph types.
5324 @item --expression=@var{expr}
5325 @itemx -e @var{expr}
5326 Consider the package @var{expr} evaluates to.
5328 This is useful to precisely refer to a package, as in this example:
5331 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
5336 @node Invoking guix environment
5337 @section Invoking @command{guix environment}
5339 @cindex reproducible build environments
5340 @cindex development environments
5341 The purpose of @command{guix environment} is to assist hackers in
5342 creating reproducible development environments without polluting their
5343 package profile. The @command{guix environment} tool takes one or more
5344 packages, builds all of their inputs, and creates a shell
5345 environment to use them.
5347 The general syntax is:
5350 guix environment @var{options} @var{package}@dots{}
5353 The following example spawns a new shell set up for the development of
5357 guix environment guile
5360 If the needed dependencies are not built yet, @command{guix environment}
5361 automatically builds them. The environment of the new shell is an augmented
5362 version of the environment that @command{guix environment} was run in.
5363 It contains the necessary search paths for building the given package
5364 added to the existing environment variables. To create a ``pure''
5365 environment, in which the original environment variables have been unset,
5366 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
5367 environment variables such as @code{PATH} in their @file{~/.bashrc}
5368 file. As a consequence, when @code{guix environment} launches it, Bash
5369 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
5370 environment variables. It is an error to define such environment
5371 variables in @file{.bashrc}; instead, they should be defined in
5372 @file{.bash_profile}, which is sourced only by log-in shells.
5373 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
5374 details on Bash start-up files.}.
5376 @vindex GUIX_ENVIRONMENT
5377 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
5378 variable in the shell it spawns. This allows users to, say, define a
5379 specific prompt for development environments in their @file{.bashrc}
5380 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
5383 if [ -n "$GUIX_ENVIRONMENT" ]
5385 export PS1="\u@@\h \w [dev]\$ "
5389 Additionally, more than one package may be specified, in which case the
5390 union of the inputs for the given packages are used. For example, the
5391 command below spawns a shell where all of the dependencies of both Guile
5392 and Emacs are available:
5395 guix environment guile emacs
5398 Sometimes an interactive shell session is not desired. An arbitrary
5399 command may be invoked by placing the @code{--} token to separate the
5400 command from the rest of the arguments:
5403 guix environment guile -- make -j4
5406 In other situations, it is more convenient to specify the list of
5407 packages needed in the environment. For example, the following command
5408 runs @command{python} from an environment containing Python@tie{}2.7 and
5412 guix environment --ad-hoc python2-numpy python-2.7 -- python
5415 Furthermore, one might want the dependencies of a package and also some
5416 additional packages that are not build-time or runtime dependencies, but
5417 are useful when developing nonetheless. Because of this, the
5418 @code{--ad-hoc} flag is positional. Packages appearing before
5419 @code{--ad-hoc} are interpreted as packages whose dependencies will be
5420 added to the environment. Packages appearing after are interpreted as
5421 packages that will be added to the environment directly. For example,
5422 the following command creates a Guix development environment that
5423 additionally includes Git and strace:
5426 guix environment guix --ad-hoc git strace
5429 Sometimes it is desirable to isolate the environment as much as
5430 possible, for maximal purity and reproducibility. In particular, when
5431 using Guix on a host distro that is not GuixSD, it is desirable to
5432 prevent access to @file{/usr/bin} and other system-wide resources from
5433 the development environment. For example, the following command spawns
5434 a Guile REPL in a ``container'' where only the store and the current
5435 working directory are mounted:
5438 guix environment --ad-hoc --container guile -- guile
5442 The @code{--container} option requires Linux-libre 3.19 or newer.
5445 The available options are summarized below.
5448 @item --expression=@var{expr}
5449 @itemx -e @var{expr}
5450 Create an environment for the package or list of packages that
5451 @var{expr} evaluates to.
5453 For example, running:
5456 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
5459 starts a shell with the environment for this specific variant of the
5465 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
5468 starts a shell with all the GuixSD base packages available.
5470 The above commands only the use default output of the given packages.
5471 To select other outputs, two element tuples can be specified:
5474 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
5477 @item --load=@var{file}
5478 @itemx -l @var{file}
5479 Create an environment for the package or list of packages that the code
5480 within @var{file} evaluates to.
5482 As an example, @var{file} might contain a definition like this
5483 (@pxref{Defining Packages}):
5486 @verbatiminclude environment-gdb.scm
5490 Include all specified packages in the resulting environment, as if an
5491 @i{ad hoc} package were defined with them as inputs. This option is
5492 useful for quickly creating an environment without having to write a
5493 package expression to contain the desired inputs.
5495 For instance, the command:
5498 guix environment --ad-hoc guile guile-sdl -- guile
5501 runs @command{guile} in an environment where Guile and Guile-SDL are
5504 Note that this example implicitly asks for the default output of
5505 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
5506 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
5507 of @code{glib} (@pxref{Packages with Multiple Outputs}).
5509 This option may be composed with the default behavior of @command{guix
5510 environment}. Packages appearing before @code{--ad-hoc} are interpreted
5511 as packages whose dependencies will be added to the environment, the
5512 default behavior. Packages appearing after are interpreted as packages
5513 that will be added to the environment directly.
5516 Unset existing environment variables when building the new environment.
5517 This has the effect of creating an environment in which search paths
5518 only contain package inputs.
5520 @item --search-paths
5521 Display the environment variable definitions that make up the
5524 @item --system=@var{system}
5525 @itemx -s @var{system}
5526 Attempt to build for @var{system}---e.g., @code{i686-linux}.
5531 Run @var{command} within an isolated container. The current working
5532 directory outside the container is mapped inside the container.
5533 Additionally, a dummy home directory is created that matches the current
5534 user's home directory, and @file{/etc/passwd} is configured accordingly.
5535 The spawned process runs as the current user outside the container, but
5536 has root privileges in the context of the container.
5540 For containers, share the network namespace with the host system.
5541 Containers created without this flag only have access to the loopback
5544 @item --expose=@var{source}[=@var{target}]
5545 For containers, expose the file system @var{source} from the host system
5546 as the read-only file system @var{target} within the container. If
5547 @var{target} is not specified, @var{source} is used as the target mount
5548 point in the container.
5550 The example below spawns a Guile REPL in a container in which the user's
5551 home directory is accessible read-only via the @file{/exchange}
5555 guix environment --container --expose=$HOME=/exchange guile -- guile
5558 @item --share=@var{source}[=@var{target}]
5559 For containers, share the file system @var{source} from the host system
5560 as the writable file system @var{target} within the container. If
5561 @var{target} is not specified, @var{source} is used as the target mount
5562 point in the container.
5564 The example below spawns a Guile REPL in a container in which the user's
5565 home directory is accessible for both reading and writing via the
5566 @file{/exchange} directory:
5569 guix environment --container --share=$HOME=/exchange guile -- guile
5573 It also supports all of the common build options that @command{guix
5574 build} supports (@pxref{Common Build Options}).
5576 @node Invoking guix publish
5577 @section Invoking @command{guix publish}
5579 The purpose of @command{guix publish} is to enable users to easily share
5580 their store with others, who can then use it as a substitute server
5581 (@pxref{Substitutes}).
5583 When @command{guix publish} runs, it spawns an HTTP server which allows
5584 anyone with network access to obtain substitutes from it. This means
5585 that any machine running Guix can also act as if it were a build farm,
5586 since the HTTP interface is compatible with Hydra, the software behind
5587 the @code{hydra.gnu.org} build farm.
5589 For security, each substitute is signed, allowing recipients to check
5590 their authenticity and integrity (@pxref{Substitutes}). Because
5591 @command{guix publish} uses the signing key of the system, which is only
5592 readable by the system administrator, it must be started as root; the
5593 @code{--user} option makes it drop root privileges early on.
5595 The signing key pair must be generated before @command{guix publish} is
5596 launched, using @command{guix archive --generate-key} (@pxref{Invoking
5599 The general syntax is:
5602 guix publish @var{options}@dots{}
5605 Running @command{guix publish} without any additional arguments will
5606 spawn an HTTP server on port 8080:
5612 Once a publishing server has been authorized (@pxref{Invoking guix
5613 archive}), the daemon may download substitutes from it:
5616 guix-daemon --substitute-urls=http://example.org:8080
5619 The following options are available:
5622 @item --port=@var{port}
5623 @itemx -p @var{port}
5624 Listen for HTTP requests on @var{port}.
5626 @item --listen=@var{host}
5627 Listen on the network interface for @var{host}. The default is to
5628 accept connections from any interface.
5630 @item --user=@var{user}
5631 @itemx -u @var{user}
5632 Change privileges to @var{user} as soon as possible---i.e., once the
5633 server socket is open and the signing key has been read.
5635 @item --ttl=@var{ttl}
5636 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
5637 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
5638 days, @code{1m} means 1 month, and so on.
5640 This allows the user's Guix to keep substitute information in cache for
5641 @var{ttl}. However, note that @code{guix publish} does not itself
5642 guarantee that the store items it provides will indeed remain available
5643 for as long as @var{ttl}.
5645 @item --repl[=@var{port}]
5646 @itemx -r [@var{port}]
5647 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
5648 Reference Manual}) on @var{port} (37146 by default). This is used
5649 primarily for debugging a running @command{guix publish} server.
5652 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
5653 add a call to @code{guix-publish-service} in the @code{services} field
5654 of the @code{operating-system} declaration (@pxref{guix-publish-service,
5655 @code{guix-publish-service}}).
5658 @node Invoking guix challenge
5659 @section Invoking @command{guix challenge}
5661 @cindex reproducible builds
5662 @cindex verifiable builds
5664 Do the binaries provided by this server really correspond to the source
5665 code it claims to build? Is a package build process deterministic?
5666 These are the questions the @command{guix challenge} command attempts to
5669 The former is obviously an important question: Before using a substitute
5670 server (@pxref{Substitutes}), one had better @emph{verify} that it
5671 provides the right binaries, and thus @emph{challenge} it. The latter
5672 is what enables the former: If package builds are deterministic, then
5673 independent builds of the package should yield the exact same result,
5674 bit for bit; if a server provides a binary different from the one
5675 obtained locally, it may be either corrupt or malicious.
5677 We know that the hash that shows up in @file{/gnu/store} file names is
5678 the hash of all the inputs of the process that built the file or
5679 directory---compilers, libraries, build scripts,
5680 etc. (@pxref{Introduction}). Assuming deterministic build processes,
5681 one store file name should map to exactly one build output.
5682 @command{guix challenge} checks whether there is, indeed, a single
5683 mapping by comparing the build outputs of several independent builds of
5684 any given store item.
5686 The command output looks like this:
5689 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
5690 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
5691 updating list of substitutes from 'https://guix.example.org'... 100.0%
5692 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
5693 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
5694 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
5695 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
5696 /gnu/store/@dots{}-git-2.5.0 contents differ:
5697 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
5698 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
5699 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
5700 /gnu/store/@dots{}-pius-2.1.1 contents differ:
5701 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
5702 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
5703 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
5707 In this example, @command{guix challenge} first scans the store to
5708 determine the set of locally-built derivations---as opposed to store
5709 items that were downloaded from a substitute server---and then queries
5710 all the substitute servers. It then reports those store items for which
5711 the servers obtained a result different from the local build.
5713 @cindex non-determinism, in package builds
5714 As an example, @code{guix.example.org} always gets a different answer.
5715 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
5716 case of Git. This might indicate that the build process of Git is
5717 non-deterministic, meaning that its output varies as a function of
5718 various things that Guix does not fully control, in spite of building
5719 packages in isolated environments (@pxref{Features}). Most common
5720 sources of non-determinism include the addition of timestamps in build
5721 results, the inclusion of random numbers, and directory listings sorted
5722 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
5725 To find out what is wrong with this Git binary, we can do something along
5726 these lines (@pxref{Invoking guix archive}):
5729 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
5730 | guix archive -x /tmp/git
5731 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
5734 This command shows the difference between the files resulting from the
5735 local build, and the files resulting from the build on
5736 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
5737 diffutils, Comparing and Merging Files}). The @command{diff} command
5738 works great for text files. When binary files differ, a better option
5739 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
5740 visualize differences for all kinds of files.
5742 Once you have done that work, you can tell whether the differences are due
5743 to a non-deterministic build process or to a malicious server. We try
5744 hard to remove sources of non-determinism in packages to make it easier
5745 to verify substitutes, but of course, this is a process that
5746 involves not just Guix, but a large part of the free software community.
5747 In the meantime, @command{guix challenge} is one tool to help address
5750 If you are writing packages for Guix, you are encouraged to check
5751 whether @code{hydra.gnu.org} and other substitute servers obtain the
5752 same build result as you did with:
5755 $ guix challenge @var{package}
5759 where @var{package} is a package specification such as
5760 @code{guile@@2.0} or @code{glibc:debug}.
5762 The general syntax is:
5765 guix challenge @var{options} [@var{packages}@dots{}]
5768 When a difference is found between the hash of a locally-built item and
5769 that of a server-provided substitute, or among substitutes provided by
5770 different servers, the command displays it as in the example above and
5771 its exit code is 2 (other non-zero exit codes denote other kinds of
5774 The one option that matters is:
5778 @item --substitute-urls=@var{urls}
5779 Consider @var{urls} the whitespace-separated list of substitute source
5785 @node Invoking guix container
5786 @section Invoking @command{guix container}
5790 As of version @value{VERSION}, this tool is experimental. The interface
5791 is subject to radical change in the future.
5794 The purpose of @command{guix container} is to manipulate processes
5795 running within an isolated environment, commonly known as a
5796 ``container'', typically created by the @command{guix environment}
5797 (@pxref{Invoking guix environment}) and @command{guix system container}
5798 (@pxref{Invoking guix system}) commands.
5800 The general syntax is:
5803 guix container @var{action} @var{options}@dots{}
5806 @var{action} specifies the operation to perform with a container, and
5807 @var{options} specifies the context-specific arguments for the action.
5809 The following actions are available:
5813 Execute a command within the context of a running container.
5818 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
5821 @var{pid} specifies the process ID of the running container.
5822 @var{program} specifies an executable file name within the root file
5823 system of the container. @var{arguments} are the additional options that
5824 will be passed to @var{program}.
5826 The following command launches an interactive login shell inside a
5827 GuixSD container, started by @command{guix system container}, and whose
5831 guix container exec 9001 /run/current-system/profile/bin/bash --login
5834 Note that the @var{pid} cannot be the parent process of a container. It
5835 must be PID 1 of the container or one of its child processes.
5839 @c *********************************************************************
5840 @node GNU Distribution
5841 @chapter GNU Distribution
5843 @cindex Guix System Distribution
5845 Guix comes with a distribution of the GNU system consisting entirely of
5846 free software@footnote{The term ``free'' here refers to the
5847 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
5848 users of that software}.}. The
5849 distribution can be installed on its own (@pxref{System Installation}),
5850 but it is also possible to install Guix as a package manager on top of
5851 an installed GNU/Linux system (@pxref{Installation}). To distinguish
5852 between the two, we refer to the standalone distribution as the Guix
5853 System Distribution, or GuixSD.
5855 The distribution provides core GNU packages such as GNU libc, GCC, and
5856 Binutils, as well as many GNU and non-GNU applications. The complete
5857 list of available packages can be browsed
5858 @url{http://www.gnu.org/software/guix/packages,on-line} or by
5859 running @command{guix package} (@pxref{Invoking guix package}):
5862 guix package --list-available
5865 Our goal is to provide a practical 100% free software distribution of
5866 Linux-based and other variants of GNU, with a focus on the promotion and
5867 tight integration of GNU components, and an emphasis on programs and
5868 tools that help users exert that freedom.
5870 Packages are currently available on the following platforms:
5875 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
5878 Intel 32-bit architecture (IA32), Linux-Libre kernel;
5881 ARMv7-A architecture with hard float, Thumb-2 and NEON,
5882 using the EABI hard-float application binary interface (ABI),
5883 and Linux-Libre kernel.
5885 @item mips64el-linux
5886 little-endian 64-bit MIPS processors, specifically the Loongson series,
5887 n32 ABI, and Linux-Libre kernel.
5891 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
5894 For information on porting to other architectures or kernels,
5898 * System Installation:: Installing the whole operating system.
5899 * System Configuration:: Configuring the operating system.
5900 * Installing Debugging Files:: Feeding the debugger.
5901 * Security Updates:: Deploying security fixes quickly.
5902 * Package Modules:: Packages from the programmer's viewpoint.
5903 * Packaging Guidelines:: Growing the distribution.
5904 * Bootstrapping:: GNU/Linux built from scratch.
5905 * Porting:: Targeting another platform or kernel.
5908 Building this distribution is a cooperative effort, and you are invited
5909 to join! @xref{Contributing}, for information about how you can help.
5911 @node System Installation
5912 @section System Installation
5914 @cindex Guix System Distribution
5915 This section explains how to install the Guix System Distribution
5916 on a machine. The Guix package manager can
5917 also be installed on top of a running GNU/Linux system,
5918 @pxref{Installation}.
5922 @c This paragraph is for people reading this from tty2 of the
5923 @c installation image.
5924 You are reading this documentation with an Info reader. For details on
5925 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
5926 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
5927 Info}. Hit @kbd{l} afterwards to come back here.
5929 Alternately, run @command{info info} in another tty to keep the manual
5935 * Limitations:: What you can expect.
5936 * Hardware Considerations:: Supported hardware.
5937 * USB Stick Installation:: Preparing the installation medium.
5938 * Preparing for Installation:: Networking, partitioning, etc.
5939 * Proceeding with the Installation:: The real thing.
5940 * Building the Installation Image:: How this comes to be.
5944 @subsection Limitations
5946 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
5947 not production-ready. It may contain bugs and lack important
5948 features. Thus, if you are looking for a stable production system that
5949 respects your freedom as a computer user, a good solution at this point
5950 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
5951 the more established GNU/Linux distributions}. We hope you can soon switch
5952 to the GuixSD without fear, of course. In the meantime, you can
5953 also keep using your distribution and try out the package manager on top
5954 of it (@pxref{Installation}).
5956 Before you proceed with the installation, be aware of the following
5957 noteworthy limitations applicable to version @value{VERSION}:
5961 The installation process does not include a graphical user interface and
5962 requires familiarity with GNU/Linux (see the following subsections to
5963 get a feel of what that means.)
5966 Support for the Logical Volume Manager (LVM) is missing.
5969 Few system services are currently supported out-of-the-box
5973 More than 3,200 packages are available, but you may
5974 occasionally find that a useful package is missing.
5977 GNOME, Xfce, and Enlightenment are available (@pxref{Desktop Services}),
5978 as well as a number of X11 window managers. However, some graphical
5979 applications may be missing, as well as KDE.
5982 You have been warned! But more than a disclaimer, this is an invitation
5983 to report issues (and success stories!), and to join us in improving it.
5984 @xref{Contributing}, for more info.
5987 @node Hardware Considerations
5988 @subsection Hardware Considerations
5990 @cindex hardware support on GuixSD
5991 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
5992 builds around the kernel Linux-libre, which means that only hardware for
5993 which free software drivers and firmware exist is supported. Nowadays,
5994 a wide range of off-the-shelf hardware is supported on
5995 GNU/Linux-libre---from keyboards to graphics cards to scanners and
5996 Ethernet controllers. Unfortunately, there are still areas where
5997 hardware vendors deny users control over their own computing, and such
5998 hardware is not supported on GuixSD.
6000 @cindex WiFi, hardware support
6001 One of the main areas where free drivers or firmware are lacking is WiFi
6002 devices. WiFi devices known to work include those using Atheros chips
6003 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
6004 driver, and for which free firmware exists and is available
6005 out-of-the-box on GuixSD, as part of @var{%base-firmware}
6006 (@pxref{operating-system Reference, @code{firmware}}).
6008 @cindex RYF, Respects Your Freedom
6009 The @uref{https://www.fsf.org/, Free Software Foundation} runs
6010 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
6011 certification program for hardware products that respect your freedom
6012 and your privacy and ensure that you have control over your device. We
6013 encourage you to check the list of RYF-certified devices.
6015 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
6016 web site. It contains a catalog of hardware devices with information
6017 about their support in GNU/Linux.
6020 @node USB Stick Installation
6021 @subsection USB Stick Installation
6023 An installation image for USB sticks can be downloaded from
6024 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
6025 where @var{system} is one of:
6029 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
6032 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
6035 This image contains a single partition with the tools necessary for an
6036 installation. It is meant to be copied @emph{as is} to a large-enough
6039 To copy the image to a USB stick, follow these steps:
6043 Decompress the image using the @command{xz} command:
6046 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
6050 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
6051 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
6052 copy the image with:
6055 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
6058 Access to @file{/dev/sdX} usually requires root privileges.
6061 Once this is done, you should be able to reboot the system and boot from
6062 the USB stick. The latter usually requires you to get in the BIOS' boot
6063 menu, where you can choose to boot from the USB stick.
6065 @node Preparing for Installation
6066 @subsection Preparing for Installation
6068 Once you have successfully booted the image on the USB stick, you should
6069 end up with a root prompt. Several console TTYs are configured and can
6070 be used to run commands as root. TTY2 shows this documentation,
6071 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
6072 Stand-alone GNU Info}). The installation system runs the GPM mouse
6073 daemon, which allows you to select text with the left mouse button and
6074 to paste it with the middle button.
6077 Installation requires access to the Internet so that any missing
6078 dependencies of your system configuration can be downloaded. See the
6079 ``Networking'' section below.
6082 The installation system includes many common tools needed for this task.
6083 But it is also a full-blown GuixSD system, which means that you can
6084 install additional packages, should you need it, using @command{guix
6085 package} (@pxref{Invoking guix package}).
6087 @subsubsection Keyboard Layout
6089 @cindex keyboard layout
6090 The installation image uses the US qwerty keyboard layout. If you want
6091 to change it, you can use the @command{loadkeys} command. For example,
6092 the following command selects the Dvorak keyboard layout:
6098 See the files under @file{/run/current-system/profile/share/keymaps} for
6099 a list of available keyboard layouts. Run @command{man loadkeys} for
6102 @subsubsection Networking
6104 Run the following command see what your network interfaces are called:
6111 @dots{} or, using the GNU/Linux-specific @command{ip} command:
6117 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
6118 Wired interfaces have a name starting with @samp{e}; for example, the
6119 interface corresponding to the first on-board Ethernet controller is
6120 called @samp{eno1}. Wireless interfaces have a name starting with
6121 @samp{w}, like @samp{w1p2s0}.
6124 @item Wired connection
6125 To configure a wired network run the following command, substituting
6126 @var{interface} with the name of the wired interface you want to use.
6129 ifconfig @var{interface} up
6132 @item Wireless connection
6133 To configure wireless networking, you can create a configuration file
6134 for the @command{wpa_supplicant} configuration tool (its location is not
6135 important) using one of the available text editors such as
6139 zile wpa_supplicant.conf
6142 As an example, the following stanza can go to this file and will work
6143 for many wireless networks, provided you give the actual SSID and
6144 passphrase for the network you are connecting to:
6148 ssid="@var{my-ssid}"
6150 psk="the network's secret passphrase"
6154 Start the wireless service and run it in the background with the
6155 following command (substitute @var{interface} with the name of the
6156 network interface you want to use):
6159 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
6162 Run @command{man wpa_supplicant} for more information.
6165 At this point, you need to acquire an IP address. On a network where IP
6166 addresses are automatically assigned @i{via} DHCP, you can run:
6169 dhclient -v @var{interface}
6172 Try to ping a server to see if networking is up and running:
6178 Setting up network access is almost always a requirement because the
6179 image does not contain all the software and tools that may be needed.
6181 @subsubsection Disk Partitioning
6183 Unless this has already been done, the next step is to partition, and
6184 then format the target partition(s).
6186 The installation image includes several partitioning tools, including
6187 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
6188 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
6189 the partition layout you want:
6195 Once you are done partitioning the target hard disk drive, you have to
6196 create a file system on the relevant partition(s)@footnote{Currently
6197 GuixSD pretty much assumes an ext4 file system. In particular, code
6198 that reads partition UUIDs and labels only works with ext4. This will
6199 be fixed in the future.}.
6201 Preferably, assign partitions a label so that you can easily and
6202 reliably refer to them in @code{file-system} declarations (@pxref{File
6203 Systems}). This is typically done using the @code{-L} option of
6204 @command{mkfs.ext4} and related commands. So, assuming the target root
6205 partition lives at @file{/dev/sda1}, a file system with the label
6206 @code{my-root} can be created with:
6209 mkfs.ext4 -L my-root /dev/sda1
6212 @c FIXME: Uncomment this once GRUB fully supports encrypted roots.
6213 @c A typical command sequence may be:
6217 @c @dots{} Create partitions etc.@dots{}
6218 @c # cryptsetup luksFormat /dev/sdX1
6219 @c # cryptsetup open --type luks /dev/sdX1 my-partition
6220 @c # mkfs.ext4 -L my-root /dev/mapper/my-partition
6223 In addition to e2fsprogs, the suite of tools to manipulate
6224 ext2/ext3/ext4 file systems, the installation image includes
6225 Cryptsetup/LUKS for disk encryption.
6227 Once that is done, mount the target root partition under @file{/mnt}
6228 with a command like (again, assuming @file{/dev/sda1} is the root
6232 mount /dev/sda1 /mnt
6235 Finally, if you plan to use one or more swap partitions (@pxref{Memory
6236 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
6237 sure to initialize them with @command{mkswap}. Assuming you have one
6238 swap partition on @file{/dev/sda2}, you would run:
6244 @node Proceeding with the Installation
6245 @subsection Proceeding with the Installation
6247 With the target partitions ready and the target root mounted on
6248 @file{/mnt}, we're ready to go. First, run:
6251 herd start cow-store /mnt
6254 This makes @file{/gnu/store} copy-on-write, such that packages added to it
6255 during the installation phase are written to the target disk on @file{/mnt}
6256 rather than kept in memory. This is necessary because the first phase of
6257 the @command{guix system init} command (see below) entails downloads or
6258 builds to @file{/gnu/store} which, initially, is an in-memory file system.
6260 Next, you have to edit a file and
6261 provide the declaration of the operating system to be installed. To
6262 that end, the installation system comes with two text editors: GNU nano
6263 (@pxref{Top,,, nano, GNU nano Manual}), and GNU Zile, an Emacs clone.
6264 We strongly recommend storing that file on the target root file system, say,
6265 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
6266 configuration file once you have rebooted into the newly-installed system.
6268 @xref{Using the Configuration System}, for an overview of the
6269 configuration file. The example configurations discussed in that
6270 section are available under @file{/etc/configuration} in the
6271 installation image. Thus, to get started with a system configuration
6272 providing a graphical display server (a ``desktop'' system), you can run
6273 something along these lines:
6277 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
6278 # zile /mnt/etc/config.scm
6281 You should pay attention to what your configuration file contains, and
6286 Make sure the @code{grub-configuration} form refers to the device you
6287 want to install GRUB on.
6290 Be sure that your partition labels match the value of their respective
6291 @code{device} fields in your @code{file-system} configuration, assuming
6292 your @code{file-system} configuration sets the value of @code{title} to
6296 Once you are done preparing the configuration file, the new system must
6297 be initialized (remember that the target root file system is mounted
6301 guix system init /mnt/etc/config.scm /mnt
6305 This copies all the necessary files and installs GRUB on
6306 @file{/dev/sdX}, unless you pass the @option{--no-grub} option. For
6307 more information, @pxref{Invoking guix system}. This command may trigger
6308 downloads or builds of missing packages, which can take some time.
6310 Once that command has completed---and hopefully succeeded!---you can run
6311 @command{reboot} and boot into the new system. The @code{root} password
6312 in the new system is initially empty; other users' passwords need to be
6313 initialized by running the @command{passwd} command as @code{root},
6314 unless your configuration specifies otherwise
6315 (@pxref{user-account-password, user account passwords}).
6317 Join us on @code{#guix} on the Freenode IRC network or on
6318 @file{guix-devel@@gnu.org} to share your experience---good or not so
6321 @node Building the Installation Image
6322 @subsection Building the Installation Image
6324 The installation image described above was built using the @command{guix
6325 system} command, specifically:
6327 @c FIXME: 1G is too much; see <http://bugs.gnu.org/23077>.
6329 guix system disk-image --image-size=1G gnu/system/install.scm
6332 Have a look at @file{gnu/system/install.scm} in the source tree,
6333 and see also @ref{Invoking guix system} for more information
6334 about the installation image.
6336 @node System Configuration
6337 @section System Configuration
6339 @cindex system configuration
6340 The Guix System Distribution supports a consistent whole-system configuration
6341 mechanism. By that we mean that all aspects of the global system
6342 configuration---such as the available system services, timezone and
6343 locale settings, user accounts---are declared in a single place. Such
6344 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
6346 One of the advantages of putting all the system configuration under the
6347 control of Guix is that it supports transactional system upgrades, and
6348 makes it possible to roll back to a previous system instantiation,
6349 should something go wrong with the new one (@pxref{Features}). Another
6350 advantage is that it makes it easy to replicate the exact same configuration
6351 across different machines, or at different points in time, without
6352 having to resort to additional administration tools layered on top of
6353 the own tools of the system.
6354 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
6356 This section describes this mechanism. First we focus on the system
6357 administrator's viewpoint---explaining how the system is configured and
6358 instantiated. Then we show how this mechanism can be extended, for
6359 instance to support new system services.
6362 * Using the Configuration System:: Customizing your GNU system.
6363 * operating-system Reference:: Detail of operating-system declarations.
6364 * File Systems:: Configuring file system mounts.
6365 * Mapped Devices:: Block device extra processing.
6366 * User Accounts:: Specifying user accounts.
6367 * Locales:: Language and cultural convention settings.
6368 * Services:: Specifying system services.
6369 * Setuid Programs:: Programs running with root privileges.
6370 * X.509 Certificates:: Authenticating HTTPS servers.
6371 * Name Service Switch:: Configuring libc's name service switch.
6372 * Initial RAM Disk:: Linux-Libre bootstrapping.
6373 * GRUB Configuration:: Configuring the boot loader.
6374 * Invoking guix system:: Instantiating a system configuration.
6375 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
6376 * Defining Services:: Adding new service definitions.
6379 @node Using the Configuration System
6380 @subsection Using the Configuration System
6382 The operating system is configured by providing an
6383 @code{operating-system} declaration in a file that can then be passed to
6384 the @command{guix system} command (@pxref{Invoking guix system}). A
6385 simple setup, with the default system services, the default Linux-Libre
6386 kernel, initial RAM disk, and boot loader looks like this:
6388 @findex operating-system
6390 @include os-config-bare-bones.texi
6393 This example should be self-describing. Some of the fields defined
6394 above, such as @code{host-name} and @code{bootloader}, are mandatory.
6395 Others, such as @code{packages} and @code{services}, can be omitted, in
6396 which case they get a default value.
6398 Below we discuss the effect of some of the most important fields
6399 (@pxref{operating-system Reference}, for details about all the available
6400 fields), and how to @dfn{instantiate} the operating system using
6401 @command{guix system}.
6403 @unnumberedsubsubsec Globally-Visible Packages
6405 @vindex %base-packages
6406 The @code{packages} field lists packages that will be globally visible
6407 on the system, for all user accounts---i.e., in every user's @code{PATH}
6408 environment variable---in addition to the per-user profiles
6409 (@pxref{Invoking guix package}). The @var{%base-packages} variable
6410 provides all the tools one would expect for basic user and administrator
6411 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
6412 the GNU Zile lightweight text editor, @command{find}, @command{grep},
6413 etc. The example above adds tcpdump to those, taken from the @code{(gnu
6414 packages admin)} module (@pxref{Package Modules}).
6416 @findex specification->package
6417 Referring to packages by variable name, like @var{tcpdump} above, has
6418 the advantage of being unambiguous; it also allows typos and such to be
6419 diagnosed right away as ``unbound variables''. The downside is that one
6420 needs to know which module defines which package, and to augment the
6421 @code{use-package-modules} line accordingly. To avoid that, one can use
6422 the @code{specification->package} procedure of the @code{(gnu packages)}
6423 module, which returns the best package for a given name or name and
6427 (use-modules (gnu packages))
6431 (packages (append (map specification->package
6432 '("tcpdump" "htop" "gnupg@@2.0"))
6436 @unnumberedsubsubsec System Services
6438 @vindex %base-services
6439 The @code{services} field lists @dfn{system services} to be made
6440 available when the system starts (@pxref{Services}).
6441 The @code{operating-system} declaration above specifies that, in
6442 addition to the basic services, we want the @command{lshd} secure shell
6443 daemon listening on port 2222 (@pxref{Networking Services,
6444 @code{lsh-service}}). Under the hood,
6445 @code{lsh-service} arranges so that @code{lshd} is started with the
6446 right command-line options, possibly with supporting configuration files
6447 generated as needed (@pxref{Defining Services}).
6449 @cindex customization, of services
6450 @findex modify-services
6451 Occasionally, instead of using the base services as is, you will want to
6452 customize them. To do this, use @code{modify-services} (@pxref{Service
6453 Reference, @code{modify-services}}) to modify the list.
6455 For example, suppose you want to modify @code{guix-daemon} and Mingetty
6456 (the console log-in) in the @var{%base-services} list (@pxref{Base
6457 Services, @code{%base-services}}). To do that, you can write the
6458 following in your operating system declaration:
6461 (define %my-services
6462 ;; My very own list of services.
6463 (modify-services %base-services
6464 (guix-service-type config =>
6467 (use-substitutes? #f)
6468 (extra-options '("--gc-keep-derivations"))))
6469 (mingetty-service-type config =>
6470 (mingetty-configuration
6472 (motd (plain-file "motd" "Howdy!"))))))
6476 (services %my-services))
6479 This changes the configuration---i.e., the service parameters---of the
6480 @code{guix-service-type} instance, and that of all the
6481 @code{mingetty-service-type} instances in the @var{%base-services} list.
6482 Observe how this is accomplished: first, we arrange for the original
6483 configuration to be bound to the identifier @code{config} in the
6484 @var{body}, and then we write the @var{body} so that it evaluates to the
6485 desired configuration. In particular, notice how we use @code{inherit}
6486 to create a new configuration which has the same values as the old
6487 configuration, but with a few modifications.
6489 The configuration for a typical ``desktop'' usage, with the X11 display
6490 server, GNOME and Xfce (users can choose which of these desktop
6491 environments to use at the log-in screen by pressing @kbd{F1}), network
6492 management, power management, and more, would look like this:
6495 @include os-config-desktop.texi
6498 A graphical environment with a choice of lightweight window managers
6499 instead of full-blown desktop environments would look like this:
6502 @include os-config-lightweight-desktop.texi
6505 @xref{Desktop Services}, for the exact list of services provided by
6506 @var{%desktop-services}. @xref{X.509 Certificates}, for background
6507 information about the @code{nss-certs} package that is used here.
6509 Again, @var{%desktop-services} is just a list of service objects. If
6510 you want to remove services from there, you can do so using the
6511 procedures for list filtering (@pxref{SRFI-1 Filtering and
6512 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
6513 following expression returns a list that contains all the services in
6514 @var{%desktop-services} minus the Avahi service:
6517 (remove (lambda (service)
6518 (eq? (service-kind service) avahi-service-type))
6522 @unnumberedsubsubsec Instantiating the System
6524 Assuming the @code{operating-system} declaration
6525 is stored in the @file{my-system-config.scm}
6526 file, the @command{guix system reconfigure my-system-config.scm} command
6527 instantiates that configuration, and makes it the default GRUB boot
6528 entry (@pxref{Invoking guix system}).
6530 The normal way to change the system configuration is by updating this
6531 file and re-running @command{guix system reconfigure}. One should never
6532 have to touch files in @command{/etc} or to run commands that modify the
6533 system state such as @command{useradd} or @command{grub-install}. In
6534 fact, you must avoid that since that would not only void your warranty
6535 but also prevent you from rolling back to previous versions of your
6536 system, should you ever need to.
6538 @cindex roll-back, of the operating system
6539 Speaking of roll-back, each time you run @command{guix system
6540 reconfigure}, a new @dfn{generation} of the system is created---without
6541 modifying or deleting previous generations. Old system generations get
6542 an entry in the GRUB boot menu, allowing you to boot them in case
6543 something went wrong with the latest generation. Reassuring, no? The
6544 @command{guix system list-generations} command lists the system
6545 generations available on disk.
6547 @unnumberedsubsubsec The Programming Interface
6549 At the Scheme level, the bulk of an @code{operating-system} declaration
6550 is instantiated with the following monadic procedure (@pxref{The Store
6553 @deffn {Monadic Procedure} operating-system-derivation os
6554 Return a derivation that builds @var{os}, an @code{operating-system}
6555 object (@pxref{Derivations}).
6557 The output of the derivation is a single directory that refers to all
6558 the packages, configuration files, and other supporting files needed to
6559 instantiate @var{os}.
6562 This procedure is provided by the @code{(gnu system)} module. Along
6563 with @code{(gnu services)} (@pxref{Services}), this module contains the
6564 guts of GuixSD. Make sure to visit it!
6567 @node operating-system Reference
6568 @subsection @code{operating-system} Reference
6570 This section summarizes all the options available in
6571 @code{operating-system} declarations (@pxref{Using the Configuration
6574 @deftp {Data Type} operating-system
6575 This is the data type representing an operating system configuration.
6576 By that, we mean all the global system configuration, not per-user
6577 configuration (@pxref{Using the Configuration System}).
6580 @item @code{kernel} (default: @var{linux-libre})
6581 The package object of the operating system kernel to use@footnote{Currently
6582 only the Linux-libre kernel is supported. In the future, it will be
6583 possible to use the GNU@tie{}Hurd.}.
6585 @item @code{kernel-arguments} (default: @code{'()})
6586 List of strings or gexps representing additional arguments to pass on
6587 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
6589 @item @code{bootloader}
6590 The system bootloader configuration object. @xref{GRUB Configuration}.
6592 @item @code{initrd} (default: @code{base-initrd})
6593 A two-argument monadic procedure that returns an initial RAM disk for
6594 the Linux kernel. @xref{Initial RAM Disk}.
6596 @item @code{firmware} (default: @var{%base-firmware})
6598 List of firmware packages loadable by the operating system kernel.
6600 The default includes firmware needed for Atheros-based WiFi devices
6601 (Linux-libre module @code{ath9k}). @xref{Hardware Considerations}, for
6602 more info on supported hardware.
6604 @item @code{host-name}
6607 @item @code{hosts-file}
6609 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
6610 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
6611 Reference Manual}). The default is a file with entries for
6612 @code{localhost} and @var{host-name}.
6614 @item @code{mapped-devices} (default: @code{'()})
6615 A list of mapped devices. @xref{Mapped Devices}.
6617 @item @code{file-systems}
6618 A list of file systems. @xref{File Systems}.
6620 @item @code{swap-devices} (default: @code{'()})
6621 @cindex swap devices
6622 A list of strings identifying devices to be used for ``swap space''
6623 (@pxref{Memory Concepts,,, libc, The GNU C Library Reference Manual}).
6624 For example, @code{'("/dev/sda3")}.
6626 @item @code{users} (default: @code{%base-user-accounts})
6627 @itemx @code{groups} (default: @var{%base-groups})
6628 List of user accounts and groups. @xref{User Accounts}.
6630 @item @code{skeletons} (default: @code{(default-skeletons)})
6631 A list target file name/file-like object tuples (@pxref{G-Expressions,
6632 file-like objects}). These are the skeleton files that will be added to
6633 the home directory of newly-created user accounts.
6635 For instance, a valid value may look like this:
6638 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
6639 (".guile" ,(plain-file "guile"
6640 "(use-modules (ice-9 readline))
6641 (activate-readline)")))
6644 @item @code{issue} (default: @var{%default-issue})
6645 A string denoting the contents of the @file{/etc/issue} file, which is
6646 displayed when users log in on a text console.
6648 @item @code{packages} (default: @var{%base-packages})
6649 The set of packages installed in the global profile, which is accessible
6650 at @file{/run/current-system/profile}.
6652 The default set includes core utilities and it is good practice to
6653 install non-core utilities in user profiles (@pxref{Invoking guix
6656 @item @code{timezone}
6657 A timezone identifying string---e.g., @code{"Europe/Paris"}.
6659 You can run the @command{tzselect} command to find out which timezone
6660 string corresponds to your region. Choosing an invalid timezone name
6661 causes @command{guix system} to fail.
6663 @item @code{locale} (default: @code{"en_US.utf8"})
6664 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
6665 Library Reference Manual}). @xref{Locales}, for more information.
6667 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
6668 The list of locale definitions to be compiled and that may be used at
6669 run time. @xref{Locales}.
6671 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
6672 The list of GNU@tie{}libc packages whose locale data and tools are used
6673 to build the locale definitions. @xref{Locales}, for compatibility
6674 considerations that justify this option.
6676 @item @code{name-service-switch} (default: @var{%default-nss})
6677 Configuration of the libc name service switch (NSS)---a
6678 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
6681 @item @code{services} (default: @var{%base-services})
6682 A list of service objects denoting system services. @xref{Services}.
6684 @item @code{pam-services} (default: @code{(base-pam-services)})
6686 @cindex pluggable authentication modules
6687 Linux @dfn{pluggable authentication module} (PAM) services.
6688 @c FIXME: Add xref to PAM services section.
6690 @item @code{setuid-programs} (default: @var{%setuid-programs})
6691 List of string-valued G-expressions denoting setuid programs.
6692 @xref{Setuid Programs}.
6694 @item @code{sudoers-file} (default: @var{%sudoers-specification})
6695 @cindex sudoers file
6696 The contents of the @file{/etc/sudoers} file as a file-like object
6697 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
6699 This file specifies which users can use the @command{sudo} command, what
6700 they are allowed to do, and what privileges they may gain. The default
6701 is that only @code{root} and members of the @code{wheel} group may use
6708 @subsection File Systems
6710 The list of file systems to be mounted is specified in the
6711 @code{file-systems} field of the operating system declaration
6712 (@pxref{Using the Configuration System}). Each file system is declared
6713 using the @code{file-system} form, like this:
6717 (mount-point "/home")
6718 (device "/dev/sda3")
6722 As usual, some of the fields are mandatory---those shown in the example
6723 above---while others can be omitted. These are described below.
6725 @deftp {Data Type} file-system
6726 Objects of this type represent file systems to be mounted. They
6727 contain the following members:
6731 This is a string specifying the type of the file system---e.g.,
6734 @item @code{mount-point}
6735 This designates the place where the file system is to be mounted.
6738 This names the ``source'' of the file system. By default it is the name
6739 of a node under @file{/dev}, but its meaning depends on the @code{title}
6740 field described below.
6742 @item @code{title} (default: @code{'device})
6743 This is a symbol that specifies how the @code{device} field is to be
6746 When it is the symbol @code{device}, then the @code{device} field is
6747 interpreted as a file name; when it is @code{label}, then @code{device}
6748 is interpreted as a partition label name; when it is @code{uuid},
6749 @code{device} is interpreted as a partition unique identifier (UUID).
6751 UUIDs may be converted from their string representation (as shown by the
6752 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
6753 @code{uuid} form expects 16-byte UUIDs as defined in
6754 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
6755 form of UUID used by the ext2 family of file systems and others, but it
6756 is different from ``UUIDs'' found in FAT file systems, for instance.},
6761 (mount-point "/home")
6764 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
6767 The @code{label} and @code{uuid} options offer a way to refer to disk
6768 partitions without having to hard-code their actual device
6769 name@footnote{Note that, while it is tempting to use
6770 @file{/dev/disk/by-uuid} and similar device names to achieve the same
6771 result, this is not recommended: These special device nodes are created
6772 by the udev daemon and may be unavailable at the time the device is
6775 However, when the source of a file system is a mapped device (@pxref{Mapped
6776 Devices}), its @code{device} field @emph{must} refer to the mapped
6777 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
6778 @code{title} must be set to @code{'device}. This is required so that
6779 the system knows that mounting the file system depends on having the
6780 corresponding device mapping established.
6782 @item @code{flags} (default: @code{'()})
6783 This is a list of symbols denoting mount flags. Recognized flags
6784 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
6785 access to special files), @code{no-suid} (ignore setuid and setgid
6786 bits), and @code{no-exec} (disallow program execution.)
6788 @item @code{options} (default: @code{#f})
6789 This is either @code{#f}, or a string denoting mount options.
6791 @item @code{mount?} (default: @code{#t})
6792 This value indicates whether to automatically mount the file system when
6793 the system is brought up. When set to @code{#f}, the file system gets
6794 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
6795 is not automatically mounted.
6797 @item @code{needed-for-boot?} (default: @code{#f})
6798 This Boolean value indicates whether the file system is needed when
6799 booting. If that is true, then the file system is mounted when the
6800 initial RAM disk (initrd) is loaded. This is always the case, for
6801 instance, for the root file system.
6803 @item @code{check?} (default: @code{#t})
6804 This Boolean indicates whether the file system needs to be checked for
6805 errors before being mounted.
6807 @item @code{create-mount-point?} (default: @code{#f})
6808 When true, the mount point is created if it does not exist yet.
6810 @item @code{dependencies} (default: @code{'()})
6811 This is a list of @code{<file-system>} objects representing file systems
6812 that must be mounted before (and unmounted after) this one.
6814 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
6815 a dependency of @file{/sys/fs/cgroup/cpu} and
6816 @file{/sys/fs/cgroup/memory}.
6821 The @code{(gnu system file-systems)} exports the following useful
6824 @defvr {Scheme Variable} %base-file-systems
6825 These are essential file systems that are required on normal systems,
6826 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
6827 below.) Operating system declarations should always contain at least
6831 @defvr {Scheme Variable} %pseudo-terminal-file-system
6832 This is the file system to be mounted as @file{/dev/pts}. It supports
6833 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
6834 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
6835 Manual}). Pseudo-terminals are used by terminal emulators such as
6839 @defvr {Scheme Variable} %shared-memory-file-system
6840 This file system is mounted as @file{/dev/shm} and is used to support
6841 memory sharing across processes (@pxref{Memory-mapped I/O,
6842 @code{shm_open},, libc, The GNU C Library Reference Manual}).
6845 @defvr {Scheme Variable} %immutable-store
6846 This file system performs a read-only ``bind mount'' of
6847 @file{/gnu/store}, making it read-only for all the users including
6848 @code{root}. This prevents against accidental modification by software
6849 running as @code{root} or by system administrators.
6851 The daemon itself is still able to write to the store: it remounts it
6852 read-write in its own ``name space.''
6855 @defvr {Scheme Variable} %binary-format-file-system
6856 The @code{binfmt_misc} file system, which allows handling of arbitrary
6857 executable file types to be delegated to user space. This requires the
6858 @code{binfmt.ko} kernel module to be loaded.
6861 @defvr {Scheme Variable} %fuse-control-file-system
6862 The @code{fusectl} file system, which allows unprivileged users to mount
6863 and unmount user-space FUSE file systems. This requires the
6864 @code{fuse.ko} kernel module to be loaded.
6867 @node Mapped Devices
6868 @subsection Mapped Devices
6870 @cindex device mapping
6871 @cindex mapped devices
6872 The Linux kernel has a notion of @dfn{device mapping}: a block device,
6873 such as a hard disk partition, can be @dfn{mapped} into another device,
6874 with additional processing over the data that flows through
6875 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
6876 concept of a ``mapped device'' and that of a file system: both boil down
6877 to @emph{translating} input/output operations made on a file to
6878 operations on its backing store. Thus, the Hurd implements mapped
6879 devices, like file systems, using the generic @dfn{translator} mechanism
6880 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
6881 typical example is encryption device mapping: all writes to the mapped
6882 device are encrypted, and all reads are deciphered, transparently.
6884 Mapped devices are declared using the @code{mapped-device} form:
6888 (source "/dev/sda3")
6890 (type luks-device-mapping))
6893 Or, better yet, like this:
6897 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
6899 (type luks-device-mapping))
6902 @cindex disk encryption
6904 This example specifies a mapping from @file{/dev/sda3} to
6905 @file{/dev/mapper/home} using LUKS---the
6906 @url{http://code.google.com/p/cryptsetup,Linux Unified Key Setup}, a
6907 standard mechanism for disk encryption. In the second example, the UUID
6908 (unique identifier) is the LUKS UUID returned for the device by a
6912 cryptsetup luksUUID /dev/sdx9
6915 The @file{/dev/mapper/home}
6916 device can then be used as the @code{device} of a @code{file-system}
6917 declaration (@pxref{File Systems}). The @code{mapped-device} form is
6920 @deftp {Data Type} mapped-device
6921 Objects of this type represent device mappings that will be made when
6922 the system boots up.
6926 This string specifies the name of the block device to be mapped, such as
6930 This string specifies the name of the mapping to be established. For
6931 example, specifying @code{"my-partition"} will lead to the creation of
6932 the @code{"/dev/mapper/my-partition"} device.
6935 This must be a @code{mapped-device-kind} object, which specifies how
6936 @var{source} is mapped to @var{target}.
6940 @defvr {Scheme Variable} luks-device-mapping
6941 This defines LUKS block device encryption using the @command{cryptsetup}
6942 command from the package with the same name. It relies on the
6943 @code{dm-crypt} Linux kernel module.
6947 @subsection User Accounts
6949 User accounts and groups are entirely managed through the
6950 @code{operating-system} declaration. They are specified with the
6951 @code{user-account} and @code{user-group} forms:
6957 (supplementary-groups '("wheel" ;allow use of sudo, etc.
6959 "video" ;video devices such as webcams
6960 "cdrom")) ;the good ol' CD-ROM
6961 (comment "Bob's sister")
6962 (home-directory "/home/alice"))
6965 When booting or upon completion of @command{guix system reconfigure},
6966 the system ensures that only the user accounts and groups specified in
6967 the @code{operating-system} declaration exist, and with the specified
6968 properties. Thus, account or group creations or modifications made by
6969 directly invoking commands such as @command{useradd} are lost upon
6970 reconfiguration or reboot. This ensures that the system remains exactly
6973 @deftp {Data Type} user-account
6974 Objects of this type represent user accounts. The following members may
6979 The name of the user account.
6982 This is the name (a string) or identifier (a number) of the user group
6983 this account belongs to.
6985 @item @code{supplementary-groups} (default: @code{'()})
6986 Optionally, this can be defined as a list of group names that this
6989 @item @code{uid} (default: @code{#f})
6990 This is the user ID for this account (a number), or @code{#f}. In the
6991 latter case, a number is automatically chosen by the system when the
6994 @item @code{comment} (default: @code{""})
6995 A comment about the account, such as the account owner's full name.
6997 @item @code{home-directory}
6998 This is the name of the home directory for the account.
7000 @item @code{shell} (default: Bash)
7001 This is a G-expression denoting the file name of a program to be used as
7002 the shell (@pxref{G-Expressions}).
7004 @item @code{system?} (default: @code{#f})
7005 This Boolean value indicates whether the account is a ``system''
7006 account. System accounts are sometimes treated specially; for instance,
7007 graphical login managers do not list them.
7009 @anchor{user-account-password}
7010 @item @code{password} (default: @code{#f})
7011 You would normally leave this field to @code{#f}, initialize user
7012 passwords as @code{root} with the @command{passwd} command, and then let
7013 users change it with @command{passwd}. Passwords set with
7014 @command{passwd} are of course preserved across reboot and
7017 If you @emph{do} want to have a preset password for an account, then
7018 this field must contain the encrypted password, as a string.
7019 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
7020 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
7021 Manual}, for information on Guile's @code{crypt} procedure.
7026 User group declarations are even simpler:
7029 (user-group (name "students"))
7032 @deftp {Data Type} user-group
7033 This type is for, well, user groups. There are just a few fields:
7037 The name of the group.
7039 @item @code{id} (default: @code{#f})
7040 The group identifier (a number). If @code{#f}, a new number is
7041 automatically allocated when the group is created.
7043 @item @code{system?} (default: @code{#f})
7044 This Boolean value indicates whether the group is a ``system'' group.
7045 System groups have low numerical IDs.
7047 @item @code{password} (default: @code{#f})
7048 What, user groups can have a password? Well, apparently yes. Unless
7049 @code{#f}, this field specifies the password of the group.
7054 For convenience, a variable lists all the basic user groups one may
7057 @defvr {Scheme Variable} %base-groups
7058 This is the list of basic user groups that users and/or packages expect
7059 to be present on the system. This includes groups such as ``root'',
7060 ``wheel'', and ``users'', as well as groups used to control access to
7061 specific devices such as ``audio'', ``disk'', and ``cdrom''.
7064 @defvr {Scheme Variable} %base-user-accounts
7065 This is the list of basic system accounts that programs may expect to
7066 find on a GNU/Linux system, such as the ``nobody'' account.
7068 Note that the ``root'' account is not included here. It is a
7069 special-case and is automatically added whether or not it is specified.
7076 A @dfn{locale} defines cultural conventions for a particular language
7077 and region of the world (@pxref{Locales,,, libc, The GNU C Library
7078 Reference Manual}). Each locale has a name that typically has the form
7079 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
7080 @code{fr_LU.utf8} designates the locale for the French language, with
7081 cultural conventions from Luxembourg, and using the UTF-8 encoding.
7083 @cindex locale definition
7084 Usually, you will want to specify the default locale for the machine
7085 using the @code{locale} field of the @code{operating-system} declaration
7086 (@pxref{operating-system Reference, @code{locale}}).
7088 The selected locale is automatically added to the @dfn{locale
7089 definitions} known to the system if needed, with its codeset inferred
7090 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
7091 @code{UTF-8} codeset. Additional locale definitions can be specified in
7092 the @code{locale-definitions} slot of @code{operating-system}---this is
7093 useful, for instance, if the codeset could not be inferred from the
7094 locale name. The default set of locale definitions includes some widely
7095 used locales, but not all the available locales, in order to save space.
7097 For instance, to add the North Frisian locale for Germany, the value of
7101 (cons (locale-definition
7102 (name "fy_DE.utf8") (source "fy_DE"))
7103 %default-locale-definitions)
7106 Likewise, to save space, one might want @code{locale-definitions} to
7107 list only the locales that are actually used, as in:
7110 (list (locale-definition
7111 (name "ja_JP.eucjp") (source "ja_JP")
7112 (charset "EUC-JP")))
7116 The compiled locale definitions are available at
7117 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
7118 version, which is the default location where the GNU@tie{}libc provided
7119 by Guix looks for locale data. This can be overridden using the
7120 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
7121 @code{LOCPATH} and locale packages}).
7123 The @code{locale-definition} form is provided by the @code{(gnu system
7124 locale)} module. Details are given below.
7126 @deftp {Data Type} locale-definition
7127 This is the data type of a locale definition.
7132 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
7133 Reference Manual}, for more information on locale names.
7136 The name of the source for that locale. This is typically the
7137 @code{@var{language}_@var{territory}} part of the locale name.
7139 @item @code{charset} (default: @code{"UTF-8"})
7140 The ``character set'' or ``code set'' for that locale,
7141 @uref{http://www.iana.org/assignments/character-sets, as defined by
7147 @defvr {Scheme Variable} %default-locale-definitions
7148 A list of commonly used UTF-8 locales, used as the default
7149 value of the @code{locale-definitions} field of @code{operating-system}
7153 @cindex normalized codeset in locale names
7154 These locale definitions use the @dfn{normalized codeset} for the part
7155 that follows the dot in the name (@pxref{Using gettextized software,
7156 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
7157 instance it has @code{uk_UA.utf8} but @emph{not}, say,
7161 @subsubsection Locale Data Compatibility Considerations
7163 @cindex incompatibility, of locale data
7164 @code{operating-system} declarations provide a @code{locale-libcs} field
7165 to specify the GNU@tie{}libc packages that are used to compile locale
7166 declarations (@pxref{operating-system Reference}). ``Why would I
7167 care?'', you may ask. Well, it turns out that the binary format of
7168 locale data is occasionally incompatible from one libc version to
7171 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
7172 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
7173 For instance, a program linked against libc version 2.21 is unable to
7174 read locale data produced with libc 2.22; worse, that program
7175 @emph{aborts} instead of simply ignoring the incompatible locale
7176 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
7177 the incompatible locale data, which is already an improvement.}.
7178 Similarly, a program linked against libc 2.22 can read most, but not
7179 all, the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
7180 data is incompatible); thus calls to @code{setlocale} may fail, but
7181 programs will not abort.
7183 The ``problem'' in GuixSD is that users have a lot of freedom: They can
7184 choose whether and when to upgrade software in their profiles, and might
7185 be using a libc version different from the one the system administrator
7186 used to build the system-wide locale data.
7188 Fortunately, unprivileged users can also install their own locale data
7189 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
7190 @code{GUIX_LOCPATH} and locale packages}).
7192 Still, it is best if the system-wide locale data at
7193 @file{/run/current-system/locale} is built for all the libc versions
7194 actually in use on the system, so that all the programs can access
7195 it---this is especially crucial on a multi-user system. To do that, the
7196 administrator can specify several libc packages in the
7197 @code{locale-libcs} field of @code{operating-system}:
7200 (use-package-modules base)
7204 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
7207 This example would lead to a system containing locale definitions for
7208 both libc 2.21 and the current version of libc in
7209 @file{/run/current-system/locale}.
7213 @subsection Services
7215 @cindex system services
7216 An important part of preparing an @code{operating-system} declaration is
7217 listing @dfn{system services} and their configuration (@pxref{Using the
7218 Configuration System}). System services are typically daemons launched
7219 when the system boots, or other actions needed at that time---e.g.,
7220 configuring network access.
7222 Services are managed by the GNU@tie{}Shepherd (@pxref{Introduction,,,
7223 shepherd, The GNU Shepherd Manual}). On a running system, the
7224 @command{herd} command allows you to list the available services, show
7225 their status, start and stop them, or do other specific operations
7226 (@pxref{Jump Start,,, shepherd, The GNU Shepherd Manual}). For example:
7232 The above command, run as @code{root}, lists the currently defined
7233 services. The @command{herd doc} command shows a synopsis of the given
7238 Run libc's name service cache daemon (nscd).
7241 The @command{start}, @command{stop}, and @command{restart} sub-commands
7242 have the effect you would expect. For instance, the commands below stop
7243 the nscd service and restart the Xorg display server:
7247 Service nscd has been stopped.
7248 # herd restart xorg-server
7249 Service xorg-server has been stopped.
7250 Service xorg-server has been started.
7253 The following sections document the available services, starting with
7254 the core services, that may be used in an @code{operating-system}
7258 * Base Services:: Essential system services.
7259 * Scheduled Job Execution:: The mcron service.
7260 * Networking Services:: Network setup, SSH daemon, etc.
7261 * X Window:: Graphical display.
7262 * Desktop Services:: D-Bus and desktop services.
7263 * Database Services:: SQL databases.
7264 * Mail Services:: IMAP, POP3, SMTP, and all that.
7265 * Web Services:: Web servers.
7266 * Various Services:: Other services.
7270 @subsubsection Base Services
7272 The @code{(gnu services base)} module provides definitions for the basic
7273 services that one expects from the system. The services exported by
7274 this module are listed below.
7276 @defvr {Scheme Variable} %base-services
7277 This variable contains a list of basic services (@pxref{Service Types
7278 and Services}, for more information on service objects) one would
7279 expect from the system: a login service (mingetty) on each tty, syslogd,
7280 the libc name service cache daemon (nscd), the udev device manager, and
7283 This is the default value of the @code{services} field of
7284 @code{operating-system} declarations. Usually, when customizing a
7285 system, you will want to append services to @var{%base-services}, like
7289 (cons* (avahi-service) (lsh-service) %base-services)
7293 @deffn {Scheme Procedure} host-name-service @var{name}
7294 Return a service that sets the host name to @var{name}.
7297 @deffn {Scheme Procedure} mingetty-service @var{config}
7298 Return a service to run mingetty according to @var{config}, a
7299 @code{<mingetty-configuration>} object, which specifies the tty to run, among
7303 @deftp {Data Type} mingetty-configuration
7304 This is the data type representing the configuration of Mingetty, which
7305 implements console log-in.
7310 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
7313 A file-like object containing the ``message of the day''.
7315 @item @code{auto-login} (default: @code{#f})
7316 When true, this field must be a string denoting the user name under
7317 which the system automatically logs in. When it is @code{#f}, a
7318 user name and password must be entered to log in.
7320 @item @code{login-program} (default: @code{#f})
7321 This must be either @code{#f}, in which case the default log-in program
7322 is used (@command{login} from the Shadow tool suite), or a gexp denoting
7323 the name of the log-in program.
7325 @item @code{login-pause?} (default: @code{#f})
7326 When set to @code{#t} in conjunction with @var{auto-login}, the user
7327 will have to press a key before the log-in shell is launched.
7329 @item @code{mingetty} (default: @var{mingetty})
7330 The Mingetty package to use.
7335 @cindex name service cache daemon
7337 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
7338 [#:name-services '()]
7339 Return a service that runs the libc name service cache daemon (nscd) with the
7340 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
7341 Service Switch}, for an example.
7344 @defvr {Scheme Variable} %nscd-default-configuration
7345 This is the default @code{<nscd-configuration>} value (see below) used
7346 by @code{nscd-service}. It uses the caches defined by
7347 @var{%nscd-default-caches}; see below.
7350 @deftp {Data Type} nscd-configuration
7351 This is the data type representing the name service cache daemon (nscd)
7356 @item @code{name-services} (default: @code{'()})
7357 List of packages denoting @dfn{name services} that must be visible to
7358 the nscd---e.g., @code{(list @var{nss-mdns})}.
7360 @item @code{glibc} (default: @var{glibc})
7361 Package object denoting the GNU C Library providing the @command{nscd}
7364 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
7365 Name of the nscd log file. This is where debugging output goes when
7366 @code{debug-level} is strictly positive.
7368 @item @code{debug-level} (default: @code{0})
7369 Integer denoting the debugging levels. Higher numbers mean that more
7370 debugging output is logged.
7372 @item @code{caches} (default: @var{%nscd-default-caches})
7373 List of @code{<nscd-cache>} objects denoting things to be cached; see
7379 @deftp {Data Type} nscd-cache
7380 Data type representing a cache database of nscd and its parameters.
7384 @item @code{database}
7385 This is a symbol representing the name of the database to be cached.
7386 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
7387 @code{services}, which designate the corresponding NSS database
7388 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
7390 @item @code{positive-time-to-live}
7391 @itemx @code{negative-time-to-live} (default: @code{20})
7392 A number representing the number of seconds during which a positive or
7393 negative lookup result remains in cache.
7395 @item @code{check-files?} (default: @code{#t})
7396 Whether to check for updates of the files corresponding to
7399 For instance, when @var{database} is @code{hosts}, setting this flag
7400 instructs nscd to check for updates in @file{/etc/hosts} and to take
7403 @item @code{persistent?} (default: @code{#t})
7404 Whether the cache should be stored persistently on disk.
7406 @item @code{shared?} (default: @code{#t})
7407 Whether the cache should be shared among users.
7409 @item @code{max-database-size} (default: 32@tie{}MiB)
7410 Maximum size in bytes of the database cache.
7412 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
7413 @c settings, so leave them out.
7418 @defvr {Scheme Variable} %nscd-default-caches
7419 List of @code{<nscd-cache>} objects used by default by
7420 @code{nscd-configuration} (see above).
7422 It enables persistent and aggressive caching of service and host name
7423 lookups. The latter provides better host name lookup performance,
7424 resilience in the face of unreliable name servers, and also better
7425 privacy---often the result of host name lookups is in local cache, so
7426 external name servers do not even need to be queried.
7430 @deffn {Scheme Procedure} syslog-service @
7431 [#:config-file @var{%default-syslog.conf}]
7432 Return a service that runs @command{syslogd}. If the configuration file
7433 name @var{config-file} is not specified, use some reasonable default
7436 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
7437 information on the configuration file syntax.
7440 @anchor{guix-configuration-type}
7441 @deftp {Data Type} guix-configuration
7442 This data type represents the configuration of the Guix build daemon.
7443 @xref{Invoking guix-daemon}, for more information.
7446 @item @code{guix} (default: @var{guix})
7447 The Guix package to use.
7449 @item @code{build-group} (default: @code{"guixbuild"})
7450 Name of the group for build user accounts.
7452 @item @code{build-accounts} (default: @code{10})
7453 Number of build user accounts to create.
7455 @item @code{authorize-key?} (default: @code{#t})
7456 Whether to authorize the substitute key for @code{hydra.gnu.org}
7457 (@pxref{Substitutes}).
7459 @item @code{use-substitutes?} (default: @code{#t})
7460 Whether to use substitutes.
7462 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
7463 The list of URLs where to look for substitutes by default.
7465 @item @code{extra-options} (default: @code{'()})
7466 List of extra command-line options for @command{guix-daemon}.
7468 @item @code{lsof} (default: @var{lsof})
7469 @itemx @code{lsh} (default: @var{lsh})
7470 The lsof and lsh packages to use.
7475 @deffn {Scheme Procedure} guix-service @var{config}
7476 Return a service that runs the Guix build daemon according to
7480 @deffn {Scheme Procedure} udev-service [#:udev udev]
7481 Run @var{udev}, which populates the @file{/dev} directory dynamically.
7484 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
7485 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
7489 @defvr {Scheme Variable} %random-seed-file
7490 This is the name of the file where some random bytes are saved by
7491 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
7492 It defaults to @file{/var/lib/random-seed}.
7495 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
7496 @cindex keyboard layout
7497 Return a service to load console keymaps from @var{files} using
7498 @command{loadkeys} command. Most likely, you want to load some default
7499 keymap, which can be done like this:
7502 (console-keymap-service "dvorak")
7505 Or, for example, for a Swedish keyboard, you may need to combine
7506 the following keymaps:
7508 (console-keymap-service "se-lat6" "se-fi-lat6")
7511 Also you can specify a full file name (or file names) of your keymap(s).
7512 See @code{man loadkeys} for details.
7516 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
7518 Run @var{gpm}, the general-purpose mouse daemon, with the given
7519 command-line @var{options}. GPM allows users to use the mouse in the console,
7520 notably to select, copy, and paste text. The default value of @var{options}
7521 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
7523 This service is not part of @var{%base-services}.
7526 @anchor{guix-publish-service}
7527 @deffn {Scheme Procedure} guix-publish-service [#:guix @var{guix}] @
7528 [#:port 80] [#:host "localhost"]
7529 Return a service that runs @command{guix publish} listening on @var{host}
7530 and @var{port} (@pxref{Invoking guix publish}).
7532 This assumes that @file{/etc/guix} already contains a signing key pair as
7533 created by @command{guix archive --generate-key} (@pxref{Invoking guix
7534 archive}). If that is not the case, the service will fail to start.
7537 @anchor{rngd-service}
7538 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
7539 [#:device "/dev/hwrng"]
7540 Return a service that runs the @command{rngd} program from @var{rng-tools}
7541 to add @var{device} to the kernel's entropy pool. The service will fail if
7542 @var{device} does not exist.
7545 @node Scheduled Job Execution
7546 @subsubsection Scheduled Job Execution
7549 @cindex scheduling jobs
7550 The @code{(gnu services mcron)} module provides an interface to
7551 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
7552 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
7553 Unix @command{cron} daemon; the main difference is that it is
7554 implemented in Guile Scheme, which provides a lot of flexibility when
7555 specifying the scheduling of jobs and their actions.
7557 The example below defines an operating system that runs the
7558 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
7559 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
7560 well as the @command{mkid} command on behalf of an unprivileged user
7561 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
7562 gexps to introduce job definitions that are passed to mcron
7563 (@pxref{G-Expressions}).
7566 (use-modules (guix) (gnu) (gnu services mcron))
7567 (use-package-modules base idutils)
7569 (define updatedb-job
7570 ;; Run 'updatedb' at 3AM every day. Here we write the
7571 ;; job's action as a Scheme procedure.
7572 #~(job '(next-hour '(3))
7574 (execl (string-append #$findutils "/bin/updatedb")
7576 "--prunepaths=/tmp /var/tmp /gnu/store"))))
7578 (define garbage-collector-job
7579 ;; Collect garbage 5 minutes after midnight every day.
7580 ;; The job's action is a shell command.
7581 #~(job "5 0 * * *" ;Vixie cron syntax
7584 (define idutils-jobs
7585 ;; Update the index database as user "charlie" at 12:15PM
7586 ;; and 19:15PM. This runs from the user's home directory.
7587 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
7588 (string-append #$idutils "/bin/mkid src")
7593 (services (cons (mcron-service (list garbage-collector-job
7599 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
7600 for more information on mcron job specifications. Below is the
7601 reference of the mcron service.
7603 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
7604 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
7605 list of gexps denoting mcron job specifications.
7607 This is a shorthand for:
7609 (service mcron-service-type
7610 (mcron-configuration (mcron mcron) (jobs jobs)))
7614 @defvr {Scheme Variable} mcron-service-type
7615 This is the type of the @code{mcron} service, whose value is an
7616 @code{mcron-configuration} object.
7618 This service type can be the target of a service extension that provides
7619 it additional job specifications (@pxref{Service Composition}). In
7620 other words, it is possible to define services that provide addition
7624 @deftp {Data Type} mcron-configuration
7625 Data type representing the configuration of mcron.
7628 @item @code{mcron} (default: @var{mcron2})
7629 The mcron package to use.
7632 This is a list of gexps (@pxref{G-Expressions}), where each gexp
7633 corresponds to an mcron job specification (@pxref{Syntax, mcron job
7634 specifications,, mcron, GNU@tie{}mcron}).
7639 @node Networking Services
7640 @subsubsection Networking Services
7642 The @code{(gnu services networking)} module provides services to configure
7643 the network interface.
7645 @cindex DHCP, networking service
7646 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
7647 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
7648 Protocol (DHCP) client, on all the non-loopback network interfaces.
7651 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
7652 [#:gateway #f] [#:name-servers @code{'()}]
7653 Return a service that starts @var{interface} with address @var{ip}. If
7654 @var{gateway} is true, it must be a string specifying the default network
7659 @cindex network management
7660 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
7661 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
7662 management daemon that aims to simplify wired and wireless networking.
7664 This service adds the @var{wicd} package to the global profile, providing
7665 several commands to interact with the daemon and configure networking:
7666 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
7667 and @command{wicd-curses} user interfaces.
7670 @cindex NetworkManager
7671 @deffn {Scheme Procedure} network-manager-service @
7672 [#:network-manager @var{network-manager}]
7673 Return a service that runs NetworkManager, a network connection manager
7674 attempting to keep network connectivity active when available.
7678 @deffn {Scheme Procedure} connman-service @
7679 [#:connman @var{connman}]
7680 Return a service that runs @url{https://01.org/connman,Connman}, a network
7683 This service adds the @var{connman} package to the global profile, providing
7684 several the @command{connmanctl} command to interact with the daemon and
7685 configure networking."
7688 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
7689 [#:name-service @var{%ntp-servers}]
7690 Return a service that runs the daemon from @var{ntp}, the
7691 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
7692 keep the system clock synchronized with that of @var{servers}.
7695 @defvr {Scheme Variable} %ntp-servers
7696 List of host names used as the default NTP servers.
7699 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
7700 Return a service to run the @uref{https://torproject.org, Tor} anonymous
7703 The daemon runs as the @code{tor} unprivileged user. It is passed
7704 @var{config-file}, a file-like object, with an additional @code{User tor} line
7705 and lines for hidden services added via @code{tor-hidden-service}. Run
7706 @command{man tor} for information about the configuration file.
7709 @cindex hidden service
7710 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
7711 Define a new Tor @dfn{hidden service} called @var{name} and implementing
7712 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
7715 '((22 "127.0.0.1:22")
7716 (80 "127.0.0.1:8080"))
7719 In this example, port 22 of the hidden service is mapped to local port 22, and
7720 port 80 is mapped to local port 8080.
7722 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
7723 the @file{hostname} file contains the @code{.onion} host name for the hidden
7726 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
7727 project's documentation} for more information.
7730 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
7731 [#:interface "127.0.0.1"] [#:port 6667] @
7732 [#:extra-settings ""]
7733 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
7734 acts as a gateway between IRC and chat networks.
7736 The daemon will listen to the interface corresponding to the IP address
7737 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
7738 local clients can connect, whereas @code{0.0.0.0} means that connections can
7739 come from any networking interface.
7741 In addition, @var{extra-settings} specifies a string to append to the
7745 Furthermore, @code{(gnu services ssh)} provides the following service.
7747 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
7748 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
7749 [#:allow-empty-passwords? #f] [#:root-login? #f] @
7750 [#:syslog-output? #t] [#:x11-forwarding? #t] @
7751 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
7752 [#:public-key-authentication? #t] [#:initialize? #t]
7753 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
7754 @var{host-key} must designate a file containing the host key, and readable
7757 When @var{daemonic?} is true, @command{lshd} will detach from the
7758 controlling terminal and log its output to syslogd, unless one sets
7759 @var{syslog-output?} to false. Obviously, it also makes lsh-service
7760 depend on existence of syslogd service. When @var{pid-file?} is true,
7761 @command{lshd} writes its PID to the file called @var{pid-file}.
7763 When @var{initialize?} is true, automatically create the seed and host key
7764 upon service activation if they do not exist yet. This may take long and
7765 require interaction.
7767 When @var{initialize?} is false, it is up to the user to initialize the
7768 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
7769 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
7770 basics,,, lsh, LSH Manual}).
7772 When @var{interfaces} is empty, lshd listens for connections on all the
7773 network interfaces; otherwise, @var{interfaces} must be a list of host names
7776 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
7777 passwords, and @var{root-login?} specifies whether to accept log-ins as
7780 The other options should be self-descriptive.
7783 @defvr {Scheme Variable} %facebook-host-aliases
7784 This variable contains a string for use in @file{/etc/hosts}
7785 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
7786 line contains a entry that maps a known server name of the Facebook
7787 on-line service---e.g., @code{www.facebook.com}---to the local
7788 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
7790 This variable is typically used in the @code{hosts-file} field of an
7791 @code{operating-system} declaration (@pxref{operating-system Reference,
7792 @file{/etc/hosts}}):
7795 (use-modules (gnu) (guix))
7798 (host-name "mymachine")
7801 ;; Create a /etc/hosts file with aliases for "localhost"
7802 ;; and "mymachine", as well as for Facebook servers.
7804 (string-append (local-host-aliases host-name)
7805 %facebook-host-aliases))))
7808 This mechanism can prevent programs running locally, such as Web
7809 browsers, from accessing Facebook.
7812 The @code{(gnu services avahi)} provides the following definition.
7814 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
7815 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
7816 [#:ipv6? #t] [#:wide-area? #f] @
7817 [#:domains-to-browse '()] [#:debug? #f]
7818 Return a service that runs @command{avahi-daemon}, a system-wide
7819 mDNS/DNS-SD responder that allows for service discovery and
7820 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
7821 extends the name service cache daemon (nscd) so that it can resolve
7822 @code{.local} host names using
7823 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
7824 add the @var{avahi} package to the system profile so that commands such as
7825 @command{avahi-browse} are directly usable.
7827 If @var{host-name} is different from @code{#f}, use that as the host name to
7828 publish for this machine; otherwise, use the machine's actual host name.
7830 When @var{publish?} is true, publishing of host names and services is allowed;
7831 in particular, avahi-daemon will publish the machine's host name and IP
7832 address via mDNS on the local network.
7834 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
7836 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
7842 @subsubsection X Window
7844 Support for the X Window graphical display system---specifically
7845 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
7846 there is no @code{xorg-service} procedure. Instead, the X server is
7847 started by the @dfn{login manager}, currently SLiM.
7849 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
7850 [#:auto-login? #f] [#:default-user ""] [#:startx] @
7851 [#:theme @var{%default-slim-theme}] @
7852 [#:theme-name @var{%default-slim-theme-name}]
7853 Return a service that spawns the SLiM graphical login manager, which in
7854 turn starts the X display server with @var{startx}, a command as returned by
7855 @code{xorg-start-command}.
7859 SLiM automatically looks for session types described by the @file{.desktop}
7860 files in @file{/run/current-system/profile/share/xsessions} and allows users
7861 to choose a session from the log-in screen using @kbd{F1}. Packages such as
7862 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
7863 adding them to the system-wide set of packages automatically makes them
7864 available at the log-in screen.
7866 In addition, @file{~/.xsession} files are honored. When available,
7867 @file{~/.xsession} must be an executable that starts a window manager
7868 and/or other X clients.
7870 When @var{allow-empty-passwords?} is true, allow logins with an empty
7871 password. When @var{auto-login?} is true, log in automatically as
7874 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
7875 @var{theme} must be a gexp denoting the name of a directory containing the
7876 theme to use. In that case, @var{theme-name} specifies the name of the
7880 @defvr {Scheme Variable} %default-theme
7881 @defvrx {Scheme Variable} %default-theme-name
7882 The G-Expression denoting the default SLiM theme and its name.
7885 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
7886 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
7887 Return a derivation that builds a @var{guile} script to start the X server
7888 from @var{xorg-server}. @var{configuration-file} is the server configuration
7889 file or a derivation that builds it; when omitted, the result of
7890 @code{xorg-configuration-file} is used.
7892 Usually the X server is started by a login manager.
7895 @deffn {Scheme Procedure} xorg-configuration-file @
7896 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
7897 Return a configuration file for the Xorg server containing search paths for
7898 all the common drivers.
7900 @var{drivers} must be either the empty list, in which case Xorg chooses a
7901 graphics driver automatically, or a list of driver names that will be tried in
7902 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
7904 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
7905 appropriate screen resolution; otherwise, it must be a list of
7906 resolutions---e.g., @code{((1024 768) (640 480))}.
7908 Last, @var{extra-config} is a list of strings or objects appended to the
7909 @code{text-file*} argument list. It is used to pass extra text to be added
7910 verbatim to the configuration file.
7913 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
7914 Add @var{package}, a package for a screen-locker or screen-saver whose
7915 command is @var{program}, to the set of setuid programs and add a PAM entry
7916 for it. For example:
7919 (screen-locker-service xlockmore "xlock")
7922 makes the good ol' XlockMore usable.
7926 @node Desktop Services
7927 @subsubsection Desktop Services
7929 The @code{(gnu services desktop)} module provides services that are
7930 usually useful in the context of a ``desktop'' setup---that is, on a
7931 machine running a graphical display server, possibly with graphical user
7932 interfaces, etc. It also defines services that provide specific desktop
7933 environments like GNOME and XFCE.
7935 To simplify things, the module defines a variable containing the set of
7936 services that users typically expect on a machine with a graphical
7937 environment and networking:
7939 @defvr {Scheme Variable} %desktop-services
7940 This is a list of services that builds upon @var{%base-services} and
7941 adds or adjusts services for a typical ``desktop'' setup.
7943 In particular, it adds a graphical login manager (@pxref{X Window,
7944 @code{slim-service}}), screen lockers,
7945 a network management tool (@pxref{Networking
7946 Services, @code{wicd-service}}), energy and color management services,
7947 the @code{elogind} login and seat manager, the Polkit privilege service,
7948 the GeoClue location service, an NTP client (@pxref{Networking
7949 Services}), the Avahi daemon, and has the name service switch service
7950 configured to be able to use @code{nss-mdns} (@pxref{Name Service
7954 The @var{%desktop-services} variable can be used as the @code{services}
7955 field of an @code{operating-system} declaration (@pxref{operating-system
7956 Reference, @code{services}}).
7958 Additionally, the @code{gnome-desktop-service} and
7959 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
7960 system. To ``add GNOME'' means that system-level services like the
7961 backlight adjustment helpers and the power management utilities are
7962 added to the system, extending @code{polkit} and @code{dbus}
7963 appropriately, allowing GNOME to operate with elevated privileges on a
7964 limited number of special-purpose system interfaces. Additionally,
7965 adding a service made by @code{gnome-desktop-service} adds the GNOME
7966 metapackage to the system profile. Likewise, adding the XFCE service
7967 not only adds the @code{xfce} metapackage to the system profile, but it
7968 also gives the Thunar file manager the ability to open a ``root-mode''
7969 file management window, if the user authenticates using the
7970 administrator's password via the standard polkit graphical interface.
7972 @deffn {Scheme Procedure} gnome-desktop-service
7973 Return a service that adds the @code{gnome} package to the system
7974 profile, and extends polkit with the actions from
7975 @code{gnome-settings-daemon}.
7978 @deffn {Scheme Procedure} xfce-desktop-service
7979 Return a service that adds the @code{xfce} package to the system profile,
7980 and extends polkit with the abilit for @code{thunar} to manipulate the
7981 file system as root from within a user session, after the user has
7982 authenticated with the administrator's password.
7985 Because the GNOME and XFCE desktop services pull in so many packages,
7986 the default @code{%desktop-services} variable doesn't include either of
7987 them by default. To add GNOME or XFCE, just @code{cons} them onto
7988 @code{%desktop-services} in the @code{services} field of your
7989 @code{operating-system}:
7993 (use-service-modules desktop)
7996 ;; cons* adds items to the list given as its last argument.
7997 (services (cons* (gnome-desktop-service)
7998 (xfce-desktop-service)
8003 These desktop environments will then be available as options in the
8004 graphical login window.
8006 The actual service definitions included in @code{%desktop-services} and
8007 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
8008 are described below.
8010 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
8011 Return a service that runs the ``system bus'', using @var{dbus}, with
8012 support for @var{services}.
8014 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
8015 facility. Its system bus is used to allow system services to communicate
8016 and to be notified of system-wide events.
8018 @var{services} must be a list of packages that provide an
8019 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
8020 and policy files. For example, to allow avahi-daemon to use the system bus,
8021 @var{services} must be equal to @code{(list avahi)}.
8024 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
8025 Return a service that runs the @code{elogind} login and
8026 seat management daemon. @uref{https://github.com/andywingo/elogind,
8027 Elogind} exposes a D-Bus interface that can be used to know which users
8028 are logged in, know what kind of sessions they have open, suspend the
8029 system, inhibit system suspend, reboot the system, and other tasks.
8031 Elogind handles most system-level power events for a computer, for
8032 example suspending the system when a lid is closed, or shutting it down
8033 when the power button is pressed.
8035 The @var{config} keyword argument specifies the configuration for
8036 elogind, and should be the result of an @code{(elogind-configuration
8037 (@var{parameter} @var{value})...)} invocation. Available parameters and
8038 their default values are:
8041 @item kill-user-processes?
8043 @item kill-only-users
8045 @item kill-exclude-users
8047 @item inhibit-delay-max-seconds
8049 @item handle-power-key
8051 @item handle-suspend-key
8053 @item handle-hibernate-key
8055 @item handle-lid-switch
8057 @item handle-lid-switch-docked
8059 @item power-key-ignore-inhibited?
8061 @item suspend-key-ignore-inhibited?
8063 @item hibernate-key-ignore-inhibited?
8065 @item lid-switch-ignore-inhibited?
8067 @item holdoff-timeout-seconds
8071 @item idle-action-seconds
8073 @item runtime-directory-size-percent
8075 @item runtime-directory-size
8080 @code{("mem" "standby" "freeze")}
8083 @item hibernate-state
8085 @item hibernate-mode
8086 @code{("platform" "shutdown")}
8087 @item hybrid-sleep-state
8089 @item hybrid-sleep-mode
8090 @code{("suspend" "platform" "shutdown")}
8094 @deffn {Scheme Procedure} polkit-service @
8095 [#:polkit @var{polkit}]
8096 Return a service that runs the
8097 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
8098 management service}, which allows system administrators to grant access to
8099 privileged operations in a structured way. By querying the Polkit service, a
8100 privileged system component can know when it should grant additional
8101 capabilities to ordinary users. For example, an ordinary user can be granted
8102 the capability to suspend the system if the user is logged in locally.
8105 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
8106 [#:watts-up-pro? #f] @
8107 [#:poll-batteries? #t] @
8108 [#:ignore-lid? #f] @
8109 [#:use-percentage-for-policy? #f] @
8110 [#:percentage-low 10] @
8111 [#:percentage-critical 3] @
8112 [#:percentage-action 2] @
8114 [#:time-critical 300] @
8115 [#:time-action 120] @
8116 [#:critical-power-action 'hybrid-sleep]
8117 Return a service that runs @uref{http://upower.freedesktop.org/,
8118 @command{upowerd}}, a system-wide monitor for power consumption and battery
8119 levels, with the given configuration settings. It implements the
8120 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
8124 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
8125 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
8126 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
8127 notifications and ways to mount/unmount disks. Programs that talk to UDisks
8128 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
8131 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
8132 Return a service that runs @command{colord}, a system service with a D-Bus
8133 interface to manage the color profiles of input and output devices such as
8134 screens and scanners. It is notably used by the GNOME Color Manager graphical
8135 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
8136 site} for more information.
8139 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
8140 Return a configuration allowing an application to access GeoClue
8141 location data. @var{name} is the Desktop ID of the application, without
8142 the @code{.desktop} part. If @var{allowed?} is true, the application
8143 will have access to location information by default. The boolean
8144 @var{system?} value indicates whether an application is a system component
8145 or not. Finally @var{users} is a list of UIDs of all users for which
8146 this application is allowed location info access. An empty users list
8147 means that all users are allowed.
8150 @defvr {Scheme Variable} %standard-geoclue-applications
8151 The standard list of well-known GeoClue application configurations,
8152 granting authority to the GNOME date-and-time utility to ask for the
8153 current location in order to set the time zone, and allowing the
8154 IceCat and Epiphany web browsers to request location information.
8155 IceCat and Epiphany both query the user before allowing a web page to
8156 know the user's location.
8159 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
8161 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
8163 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
8164 [#:submission-nick "geoclue"] @
8165 [#:applications %standard-geoclue-applications]
8166 Return a service that runs the GeoClue location service. This service
8167 provides a D-Bus interface to allow applications to request access to a
8168 user's physical location, and optionally to add information to online
8169 location databases. See
8170 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
8171 web site} for more information.
8174 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
8175 Return a service that runs the @command{bluetoothd} daemon, which manages
8176 all the Bluetooth devices and provides a number of D-Bus interfaces.
8178 Users need to be in the @code{lp} group to access the D-Bus service.
8181 @node Database Services
8182 @subsubsection Database Services
8184 The @code{(gnu services databases)} module provides the following services.
8186 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
8187 [#:config-file] [#:data-directory ``/var/lib/postgresql/data'']
8188 Return a service that runs @var{postgresql}, the PostgreSQL database
8191 The PostgreSQL daemon loads its runtime configuration from
8192 @var{config-file} and stores the database cluster in
8193 @var{data-directory}.
8196 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
8197 Return a service that runs @command{mysqld}, the MySQL or MariaDB
8200 The optional @var{config} argument specifies the configuration for
8201 @command{mysqld}, which should be a @code{<mysql-configuraiton>} object.
8204 @deftp {Data Type} mysql-configuration
8205 Data type representing the configuration of @var{mysql-service}.
8208 @item @code{mysql} (default: @var{mariadb})
8209 Package object of the MySQL database server, can be either @var{mariadb}
8212 For MySQL, a temorary root password will be displayed at activation time.
8213 For MariaDB, the root password is empty.
8218 @subsubsection Mail Services
8220 The @code{(gnu services mail)} module provides Guix service definitions
8221 for mail services. Currently the only implemented service is Dovecot,
8222 an IMAP, POP3, and LMTP server.
8224 Guix does not yet have a mail transfer agent (MTA), although for some
8225 lightweight purposes the @code{esmtp} relay-only MTA may suffice. Help
8226 is needed to properly integrate a full MTA, such as Postfix. Patches
8229 To add an IMAP/POP3 server to a GuixSD system, add a
8230 @code{dovecot-service} to the operating system definition:
8232 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
8233 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
8236 By default, Dovecot does not need much configuration; the default
8237 configuration object created by @code{(dovecot-configuration)} will
8238 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
8239 certificate will be generated for TLS-protected connections, though
8240 Dovecot will also listen on cleartext ports by default. There are a
8241 number of options, though, which mail administrators might need to change,
8242 and as is the case with other services, Guix allows the system
8243 administrator to specify these parameters via a uniform Scheme interface.
8245 For example, to specify that mail is located at @code{maildir~/.mail},
8246 one would instantiate the Dovecot service like this:
8249 (dovecot-service #:config
8250 (dovecot-configuration
8251 (mail-location "maildir:~/.mail")))
8254 The available configuration parameters follow. Each parameter
8255 definition is preceded by its type; for example, @samp{string-list foo}
8256 indicates that the @code{foo} parameter should be specified as a list of
8257 strings. There is also a way to specify the configuration as a string,
8258 if you have an old @code{dovecot.conf} file that you want to port over
8259 from some other system; see the end for more details.
8261 @c The following documentation was initially generated by
8262 @c (generate-documentation) in (gnu services mail). Manually maintained
8263 @c documentation is better, so we shouldn't hesitate to edit below as
8264 @c needed. However if the change you want to make to this documentation
8265 @c can be done in an automated way, it's probably easier to change
8266 @c (generate-documentation) than to make it below and have to deal with
8267 @c the churn as dovecot updates.
8269 Available @code{dovecot-configuration} fields are:
8271 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
8272 The dovecot package.
8275 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
8276 A list of IPs or hosts where to listen for connections. @samp{*}
8277 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
8278 interfaces. If you want to specify non-default ports or anything more
8279 complex, customize the address and port fields of the
8280 @samp{inet-listener} of the specific services you are interested in.
8283 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
8284 List of protocols we want to serve. Available protocols include
8285 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
8287 Available @code{protocol-configuration} fields are:
8289 @deftypevr {@code{protocol-configuration} parameter} string name
8290 The name of the protocol.
8293 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
8294 UNIX socket path to the master authentication server to find users.
8295 This is used by imap (for shared users) and lda.
8296 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
8299 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
8300 Space separated list of plugins to load.
8303 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
8304 Maximum number of IMAP connections allowed for a user from each IP
8305 address. NOTE: The username is compared case-sensitively.
8306 Defaults to @samp{10}.
8311 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
8312 List of services to enable. Available services include @samp{imap},
8313 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
8316 Available @code{service-configuration} fields are:
8318 @deftypevr {@code{service-configuration} parameter} string kind
8319 The service kind. Valid values include @code{director},
8320 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
8321 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
8322 @code{tcpwrap}, @code{quota-warning}, or anything else.
8325 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
8326 Listeners for the service. A listener is either a
8327 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
8328 an @code{inet-listener-configuration}.
8329 Defaults to @samp{()}.
8331 Available @code{unix-listener-configuration} fields are:
8333 @deftypevr {@code{unix-listener-configuration} parameter} file-name path
8334 The file name on which to listen.
8337 @deftypevr {@code{unix-listener-configuration} parameter} string mode
8338 The access mode for the socket.
8339 Defaults to @samp{"0600"}.
8342 @deftypevr {@code{unix-listener-configuration} parameter} string user
8343 The user to own the socket.
8344 Defaults to @samp{""}.
8347 @deftypevr {@code{unix-listener-configuration} parameter} string group
8348 The group to own the socket.
8349 Defaults to @samp{""}.
8353 Available @code{fifo-listener-configuration} fields are:
8355 @deftypevr {@code{fifo-listener-configuration} parameter} file-name path
8356 The file name on which to listen.
8359 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
8360 The access mode for the socket.
8361 Defaults to @samp{"0600"}.
8364 @deftypevr {@code{fifo-listener-configuration} parameter} string user
8365 The user to own the socket.
8366 Defaults to @samp{""}.
8369 @deftypevr {@code{fifo-listener-configuration} parameter} string group
8370 The group to own the socket.
8371 Defaults to @samp{""}.
8375 Available @code{inet-listener-configuration} fields are:
8377 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
8378 The protocol to listen for.
8381 @deftypevr {@code{inet-listener-configuration} parameter} string address
8382 The address on which to listen, or empty for all addresses.
8383 Defaults to @samp{""}.
8386 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
8387 The port on which to listen.
8390 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
8391 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
8393 Defaults to @samp{#t}.
8398 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
8399 Number of connections to handle before starting a new process.
8400 Typically the only useful values are 0 (unlimited) or 1. 1 is more
8401 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
8402 Defaults to @samp{1}.
8405 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
8406 Number of processes to always keep waiting for more connections.
8407 Defaults to @samp{0}.
8410 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
8411 If you set @samp{service-count 0}, you probably need to grow
8413 Defaults to @samp{256000000}.
8418 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
8419 Dict configuration, as created by the @code{dict-configuration}
8422 Available @code{dict-configuration} fields are:
8424 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
8425 A list of key-value pairs that this dict should hold.
8426 Defaults to @samp{()}.
8431 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
8432 A list of passdb configurations, each one created by the
8433 @code{passdb-configuration} constructor.
8435 Available @code{passdb-configuration} fields are:
8437 @deftypevr {@code{passdb-configuration} parameter} string driver
8438 The driver that the passdb should use. Valid values include
8439 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
8441 Defaults to @samp{"pam"}.
8444 @deftypevr {@code{passdb-configuration} parameter} free-form-args args
8445 A list of key-value args to the passdb driver.
8446 Defaults to @samp{()}.
8451 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
8452 List of userdb configurations, each one created by the
8453 @code{userdb-configuration} constructor.
8455 Available @code{userdb-configuration} fields are:
8457 @deftypevr {@code{userdb-configuration} parameter} string driver
8458 The driver that the userdb should use. Valid values include
8459 @samp{passwd} and @samp{static}.
8460 Defaults to @samp{"passwd"}.
8463 @deftypevr {@code{userdb-configuration} parameter} free-form-args args
8464 A list of key-value args to the userdb driver.
8465 Defaults to @samp{()}.
8468 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
8469 Override fields from passwd.
8470 Defaults to @samp{()}.
8475 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
8476 Plug-in configuration, created by the @code{plugin-configuration}
8480 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
8481 List of namespaces. Each item in the list is created by the
8482 @code{namespace-configuration} constructor.
8484 Available @code{namespace-configuration} fields are:
8486 @deftypevr {@code{namespace-configuration} parameter} string name
8487 Name for this namespace.
8490 @deftypevr {@code{namespace-configuration} parameter} string type
8491 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
8492 Defaults to @samp{"private"}.
8495 @deftypevr {@code{namespace-configuration} parameter} string separator
8496 Hierarchy separator to use. You should use the same separator for
8497 all namespaces or some clients get confused. @samp{/} is usually a good
8498 one. The default however depends on the underlying mail storage
8500 Defaults to @samp{""}.
8503 @deftypevr {@code{namespace-configuration} parameter} string prefix
8504 Prefix required to access this namespace. This needs to be
8505 different for all namespaces. For example @samp{Public/}.
8506 Defaults to @samp{""}.
8509 @deftypevr {@code{namespace-configuration} parameter} string location
8510 Physical location of the mailbox. This is in the same format as
8511 mail_location, which is also the default for it.
8512 Defaults to @samp{""}.
8515 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
8516 There can be only one INBOX, and this setting defines which
8518 Defaults to @samp{#f}.
8521 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
8522 If namespace is hidden, it's not advertised to clients via NAMESPACE
8523 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
8524 useful when converting from another server with different namespaces
8525 which you want to deprecate but still keep working. For example you can
8526 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
8528 Defaults to @samp{#f}.
8531 @deftypevr {@code{namespace-configuration} parameter} boolean list?
8532 Show the mailboxes under this namespace with the LIST command. This
8533 makes the namespace visible for clients that do not support the NAMESPACE
8534 extension. The special @code{children} value lists child mailboxes, but
8535 hides the namespace prefix.
8536 Defaults to @samp{#t}.
8539 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
8540 Namespace handles its own subscriptions. If set to @code{#f}, the
8541 parent namespace handles them. The empty prefix should always have this
8543 Defaults to @samp{#t}.
8546 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
8547 List of predefined mailboxes in this namespace.
8548 Defaults to @samp{()}.
8550 Available @code{mailbox-configuration} fields are:
8552 @deftypevr {@code{mailbox-configuration} parameter} string name
8553 Name for this mailbox.
8556 @deftypevr {@code{mailbox-configuration} parameter} string auto
8557 @samp{create} will automatically create this mailbox.
8558 @samp{subscribe} will both create and subscribe to the mailbox.
8559 Defaults to @samp{"no"}.
8562 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
8563 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
8564 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
8565 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
8566 Defaults to @samp{()}.
8573 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
8574 Base directory where to store runtime data.
8575 Defaults to @samp{"/var/run/dovecot/"}.
8578 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
8579 Greeting message for clients.
8580 Defaults to @samp{"Dovecot ready."}.
8583 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
8584 List of trusted network ranges. Connections from these IPs are
8585 allowed to override their IP addresses and ports (for logging and for
8586 authentication checks). @samp{disable-plaintext-auth} is also ignored
8587 for these networks. Typically you would specify your IMAP proxy servers
8589 Defaults to @samp{()}.
8592 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
8593 List of login access check sockets (e.g. tcpwrap).
8594 Defaults to @samp{()}.
8597 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
8598 Show more verbose process titles (in ps). Currently shows user name
8599 and IP address. Useful for seeing who is actually using the IMAP
8600 processes (e.g. shared mailboxes or if the same uid is used for multiple
8602 Defaults to @samp{#f}.
8605 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
8606 Should all processes be killed when Dovecot master process shuts down.
8607 Setting this to @code{#f} means that Dovecot can be upgraded without
8608 forcing existing client connections to close (although that could also
8609 be a problem if the upgrade is e.g. due to a security fix).
8610 Defaults to @samp{#t}.
8613 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
8614 If non-zero, run mail commands via this many connections to doveadm
8615 server, instead of running them directly in the same process.
8616 Defaults to @samp{0}.
8619 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
8620 UNIX socket or host:port used for connecting to doveadm server.
8621 Defaults to @samp{"doveadm-server"}.
8624 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
8625 List of environment variables that are preserved on Dovecot startup
8626 and passed down to all of its child processes. You can also give
8627 key=value pairs to always set specific settings.
8630 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
8631 Disable LOGIN command and all other plaintext authentications unless
8632 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
8633 matches the local IP (i.e. you're connecting from the same computer),
8634 the connection is considered secure and plaintext authentication is
8635 allowed. See also ssl=required setting.
8636 Defaults to @samp{#t}.
8639 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
8640 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
8641 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
8642 for caching to be used.
8643 Defaults to @samp{0}.
8646 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
8647 Time to live for cached data. After TTL expires the cached record
8648 is no longer used, *except* if the main database lookup returns internal
8649 failure. We also try to handle password changes automatically: If
8650 user's previous authentication was successful, but this one wasn't, the
8651 cache isn't used. For now this works only with plaintext
8653 Defaults to @samp{"1 hour"}.
8656 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
8657 TTL for negative hits (user not found, password mismatch).
8658 0 disables caching them completely.
8659 Defaults to @samp{"1 hour"}.
8662 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
8663 List of realms for SASL authentication mechanisms that need them.
8664 You can leave it empty if you don't want to support multiple realms.
8665 Many clients simply use the first one listed here, so keep the default
8667 Defaults to @samp{()}.
8670 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
8671 Default realm/domain to use if none was specified. This is used for
8672 both SASL realms and appending @@domain to username in plaintext
8674 Defaults to @samp{""}.
8677 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
8678 List of allowed characters in username. If the user-given username
8679 contains a character not listed in here, the login automatically fails.
8680 This is just an extra check to make sure user can't exploit any
8681 potential quote escaping vulnerabilities with SQL/LDAP databases. If
8682 you want to allow all characters, set this value to empty.
8683 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
8686 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
8687 Username character translations before it's looked up from
8688 databases. The value contains series of from -> to characters. For
8689 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
8690 translated to @samp{@@}.
8691 Defaults to @samp{""}.
8694 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
8695 Username formatting before it's looked up from databases. You can
8696 use the standard variables here, e.g. %Lu would lowercase the username,
8697 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
8698 change the @samp{@@} into @samp{-AT-}. This translation is done after
8699 @samp{auth-username-translation} changes.
8700 Defaults to @samp{"%Lu"}.
8703 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
8704 If you want to allow master users to log in by specifying the master
8705 username within the normal username string (i.e. not using SASL
8706 mechanism's support for it), you can specify the separator character
8707 here. The format is then <username><separator><master username>.
8708 UW-IMAP uses @samp{*} as the separator, so that could be a good
8710 Defaults to @samp{""}.
8713 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
8714 Username to use for users logging in with ANONYMOUS SASL
8716 Defaults to @samp{"anonymous"}.
8719 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
8720 Maximum number of dovecot-auth worker processes. They're used to
8721 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
8722 They're automatically created and destroyed as needed.
8723 Defaults to @samp{30}.
8726 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
8727 Host name to use in GSSAPI principal names. The default is to use
8728 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
8729 allow all keytab entries.
8730 Defaults to @samp{""}.
8733 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
8734 Kerberos keytab to use for the GSSAPI mechanism. Will use the
8735 system default (usually /etc/krb5.keytab) if not specified. You may
8736 need to change the auth service to run as root to be able to read this
8738 Defaults to @samp{""}.
8741 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
8742 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
8743 and @samp{ntlm-auth} helper.
8744 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
8745 Defaults to @samp{#f}.
8748 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
8749 Path for Samba's @samp{ntlm-auth} helper binary.
8750 Defaults to @samp{"/usr/bin/ntlm_auth"}.
8753 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
8754 Time to delay before replying to failed authentications.
8755 Defaults to @samp{"2 secs"}.
8758 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
8759 Require a valid SSL client certificate or the authentication
8761 Defaults to @samp{#f}.
8764 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
8765 Take the username from client's SSL certificate, using
8766 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
8768 Defaults to @samp{#f}.
8771 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
8772 List of wanted authentication mechanisms. Supported mechanisms are:
8773 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
8774 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
8775 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
8776 @samp{disable-plaintext-auth} setting.
8779 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
8780 List of IPs or hostnames to all director servers, including ourself.
8781 Ports can be specified as ip:port. The default port is the same as what
8782 director service's @samp{inet-listener} is using.
8783 Defaults to @samp{()}.
8786 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
8787 List of IPs or hostnames to all backend mail servers. Ranges are
8788 allowed too, like 10.0.0.10-10.0.0.30.
8789 Defaults to @samp{()}.
8792 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
8793 How long to redirect users to a specific server after it no longer
8794 has any connections.
8795 Defaults to @samp{"15 min"}.
8798 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
8799 TCP/IP port that accepts doveadm connections (instead of director
8800 connections) If you enable this, you'll also need to add
8801 @samp{inet-listener} for the port.
8802 Defaults to @samp{0}.
8805 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
8806 How the username is translated before being hashed. Useful values
8807 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
8808 are shared within domain.
8809 Defaults to @samp{"%Lu"}.
8812 @deftypevr {@code{dovecot-configuration} parameter} string log-path
8813 Log file to use for error messages. @samp{syslog} logs to syslog,
8814 @samp{/dev/stderr} logs to stderr.
8815 Defaults to @samp{"syslog"}.
8818 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
8819 Log file to use for informational messages. Defaults to
8821 Defaults to @samp{""}.
8824 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
8825 Log file to use for debug messages. Defaults to
8826 @samp{info-log-path}.
8827 Defaults to @samp{""}.
8830 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
8831 Syslog facility to use if you're logging to syslog. Usually if you
8832 don't want to use @samp{mail}, you'll use local0..local7. Also other
8833 standard facilities are supported.
8834 Defaults to @samp{"mail"}.
8837 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
8838 Log unsuccessful authentication attempts and the reasons why they
8840 Defaults to @samp{#f}.
8843 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
8844 In case of password mismatches, log the attempted password. Valid
8845 values are no, plain and sha1. sha1 can be useful for detecting brute
8846 force password attempts vs. user simply trying the same password over
8847 and over again. You can also truncate the value to n chars by appending
8849 Defaults to @samp{#f}.
8852 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
8853 Even more verbose logging for debugging purposes. Shows for example
8855 Defaults to @samp{#f}.
8858 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
8859 In case of password mismatches, log the passwords and used scheme so
8860 the problem can be debugged. Enabling this also enables
8862 Defaults to @samp{#f}.
8865 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
8866 Enable mail process debugging. This can help you figure out why
8867 Dovecot isn't finding your mails.
8868 Defaults to @samp{#f}.
8871 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
8872 Show protocol level SSL errors.
8873 Defaults to @samp{#f}.
8876 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
8877 Prefix for each line written to log file. % codes are in
8879 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
8882 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
8883 List of elements we want to log. The elements which have a
8884 non-empty variable value are joined together to form a comma-separated
8888 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
8889 Login log format. %s contains @samp{login-log-format-elements}
8890 string, %$ contains the data we want to log.
8891 Defaults to @samp{"%$: %s"}.
8894 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
8895 Log prefix for mail processes. See doc/wiki/Variables.txt for list
8896 of possible variables you can use.
8897 Defaults to @samp{"\"%s(%u): \""}.
8900 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
8901 Format to use for logging mail deliveries. You can use variables:
8904 Delivery status message (e.g. @samp{saved to INBOX})
8916 Defaults to @samp{"msgid=%m: %$"}.
8919 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
8920 Location for users' mailboxes. The default is empty, which means
8921 that Dovecot tries to find the mailboxes automatically. This won't work
8922 if the user doesn't yet have any mail, so you should explicitly tell
8923 Dovecot the full location.
8925 If you're using mbox, giving a path to the INBOX
8926 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
8927 where the other mailboxes are kept. This is called the "root mail
8928 directory", and it must be the first path given in the
8929 @samp{mail-location} setting.
8931 There are a few special variables you can use, eg.:
8937 user part in user@@domain, same as %u if there's no domain
8939 domain part in user@@domain, empty if there's no domain
8944 See doc/wiki/Variables.txt for full list. Some examples:
8946 @item maildir:~/Maildir
8947 @item mbox:~/mail:INBOX=/var/mail/%u
8948 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
8950 Defaults to @samp{""}.
8953 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
8954 System user and group used to access mails. If you use multiple,
8955 userdb can override these by returning uid or gid fields. You can use
8956 either numbers or names. <doc/wiki/UserIds.txt>.
8957 Defaults to @samp{""}.
8960 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
8962 Defaults to @samp{""}.
8965 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
8966 Group to enable temporarily for privileged operations. Currently
8967 this is used only with INBOX when either its initial creation or
8968 dotlocking fails. Typically this is set to "mail" to give access to
8970 Defaults to @samp{""}.
8973 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
8974 Grant access to these supplementary groups for mail processes.
8975 Typically these are used to set up access to shared mailboxes. Note
8976 that it may be dangerous to set these if users can create
8977 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
8978 could allow a user to delete others' mailboxes, or ln -s
8979 /secret/shared/box ~/mail/mybox would allow reading it).
8980 Defaults to @samp{""}.
8983 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
8984 Allow full filesystem access to clients. There's no access checks
8985 other than what the operating system does for the active UID/GID. It
8986 works with both maildir and mboxes, allowing you to prefix mailboxes
8987 names with e.g. /path/ or ~user/.
8988 Defaults to @samp{#f}.
8991 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
8992 Don't use mmap() at all. This is required if you store indexes to
8993 shared filesystems (NFS or clustered filesystem).
8994 Defaults to @samp{#f}.
8997 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
8998 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
8999 supports @samp{O_EXCL} since version 3, so this should be safe to use
9000 nowadays by default.
9001 Defaults to @samp{#t}.
9004 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
9005 When to use fsync() or fdatasync() calls:
9008 Whenever necessary to avoid losing important data
9010 Useful with e.g. NFS when write()s are delayed
9012 Never use it (best performance, but crashes can lose data).
9014 Defaults to @samp{"optimized"}.
9017 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
9018 Mail storage exists in NFS. Set this to yes to make Dovecot flush
9019 NFS caches whenever needed. If you're using only a single mail server
9021 Defaults to @samp{#f}.
9024 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
9025 Mail index files also exist in NFS. Setting this to yes requires
9026 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
9027 Defaults to @samp{#f}.
9030 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
9031 Locking method for index files. Alternatives are fcntl, flock and
9032 dotlock. Dotlocking uses some tricks which may create more disk I/O
9033 than other locking methods. NFS users: flock doesn't work, remember to
9034 change @samp{mmap-disable}.
9035 Defaults to @samp{"fcntl"}.
9038 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
9039 Directory in which LDA/LMTP temporarily stores incoming mails >128
9041 Defaults to @samp{"/tmp"}.
9044 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
9045 Valid UID range for users. This is mostly to make sure that users can't
9046 log in as daemons or other system users. Note that denying root logins is
9047 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
9049 Defaults to @samp{500}.
9052 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
9054 Defaults to @samp{0}.
9057 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
9058 Valid GID range for users. Users having non-valid GID as primary group ID
9059 aren't allowed to log in. If user belongs to supplementary groups with
9060 non-valid GIDs, those groups are not set.
9061 Defaults to @samp{1}.
9064 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
9066 Defaults to @samp{0}.
9069 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
9070 Maximum allowed length for mail keyword name. It's only forced when
9071 trying to create new keywords.
9072 Defaults to @samp{50}.
9075 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
9076 List of directories under which chrooting is allowed for mail
9077 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
9078 too). This setting doesn't affect @samp{login-chroot}
9079 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
9080 "/./" in home dirs are ignored. WARNING: Never add directories here
9081 which local users can modify, that may lead to root exploit. Usually
9082 this should be done only if you don't allow shell access for users.
9083 <doc/wiki/Chrooting.txt>.
9084 Defaults to @samp{()}.
9087 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
9088 Default chroot directory for mail processes. This can be overridden
9089 for specific users in user database by giving /./ in user's home
9090 directory (e.g. /home/./user chroots into /home). Note that usually
9091 there is no real need to do chrooting, Dovecot doesn't allow users to
9092 access files outside their mail directory anyway. If your home
9093 directories are prefixed with the chroot directory, append "/." to
9094 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
9095 Defaults to @samp{""}.
9098 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
9099 UNIX socket path to master authentication server to find users.
9100 This is used by imap (for shared users) and lda.
9101 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
9104 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
9105 Directory where to look up mail plugins.
9106 Defaults to @samp{"/usr/lib/dovecot"}.
9109 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
9110 List of plugins to load for all services. Plugins specific to IMAP,
9111 LDA, etc. are added to this list in their own .conf files.
9112 Defaults to @samp{()}.
9115 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
9116 The minimum number of mails in a mailbox before updates are done to
9117 cache file. This allows optimizing Dovecot's behavior to do less disk
9118 writes at the cost of more disk reads.
9119 Defaults to @samp{0}.
9122 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
9123 When IDLE command is running, mailbox is checked once in a while to
9124 see if there are any new mails or other changes. This setting defines
9125 the minimum time to wait between those checks. Dovecot can also use
9126 dnotify, inotify and kqueue to find out immediately when changes
9128 Defaults to @samp{"30 secs"}.
9131 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
9132 Save mails with CR+LF instead of plain LF. This makes sending those
9133 mails take less CPU, especially with sendfile() syscall with Linux and
9134 FreeBSD. But it also creates a bit more disk I/O which may just make it
9135 slower. Also note that if other software reads the mboxes/maildirs,
9136 they may handle the extra CRs wrong and cause problems.
9137 Defaults to @samp{#f}.
9140 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
9141 By default LIST command returns all entries in maildir beginning
9142 with a dot. Enabling this option makes Dovecot return only entries
9143 which are directories. This is done by stat()ing each entry, so it
9144 causes more disk I/O.
9145 (For systems setting struct @samp{dirent->d_type} this check is free
9146 and it's done always regardless of this setting).
9147 Defaults to @samp{#f}.
9150 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
9151 When copying a message, do it with hard links whenever possible.
9152 This makes the performance much better, and it's unlikely to have any
9154 Defaults to @samp{#t}.
9157 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
9158 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
9159 directory only when its mtime changes unexpectedly or when we can't find
9161 Defaults to @samp{#f}.
9164 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
9165 Which locking methods to use for locking mbox. There are four
9170 Create <mailbox>.lock file. This is the oldest and most NFS-safe
9171 solution. If you want to use /var/mail/ like directory, the users will
9172 need write access to that directory.
9174 Same as dotlock, but if it fails because of permissions or because there
9175 isn't enough disk space, just skip it.
9177 Use this if possible. Works with NFS too if lockd is used.
9179 May not exist in all systems. Doesn't work with NFS.
9181 May not exist in all systems. Doesn't work with NFS.
9184 You can use multiple locking methods; if you do the order they're declared
9185 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
9186 locking methods as well. Some operating systems don't allow using some of
9187 them simultaneously.
9190 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
9194 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
9195 Maximum time to wait for lock (all of them) before aborting.
9196 Defaults to @samp{"5 mins"}.
9199 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
9200 If dotlock exists but the mailbox isn't modified in any way,
9201 override the lock file after this much time.
9202 Defaults to @samp{"2 mins"}.
9205 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
9206 When mbox changes unexpectedly we have to fully read it to find out
9207 what changed. If the mbox is large this can take a long time. Since
9208 the change is usually just a newly appended mail, it'd be faster to
9209 simply read the new mails. If this setting is enabled, Dovecot does
9210 this but still safely fallbacks to re-reading the whole mbox file
9211 whenever something in mbox isn't how it's expected to be. The only real
9212 downside to this setting is that if some other MUA changes message
9213 flags, Dovecot doesn't notice it immediately. Note that a full sync is
9214 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
9215 Defaults to @samp{#t}.
9218 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
9219 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
9220 EXAMINE, EXPUNGE or CHECK commands. If this is set,
9221 @samp{mbox-dirty-syncs} is ignored.
9222 Defaults to @samp{#f}.
9225 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
9226 Delay writing mbox headers until doing a full write sync (EXPUNGE
9227 and CHECK commands and when closing the mailbox). This is especially
9228 useful for POP3 where clients often delete all mails. The downside is
9229 that our changes aren't immediately visible to other MUAs.
9230 Defaults to @samp{#t}.
9233 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
9234 If mbox size is smaller than this (e.g. 100k), don't write index
9235 files. If an index file already exists it's still read, just not
9237 Defaults to @samp{0}.
9240 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
9241 Maximum dbox file size until it's rotated.
9242 Defaults to @samp{2000000}.
9245 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
9246 Maximum dbox file age until it's rotated. Typically in days. Day
9247 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
9249 Defaults to @samp{"1d"}.
9252 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
9253 When creating new mdbox files, immediately preallocate their size to
9254 @samp{mdbox-rotate-size}. This setting currently works only in Linux
9255 with some filesystems (ext4, xfs).
9256 Defaults to @samp{#f}.
9259 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
9260 sdbox and mdbox support saving mail attachments to external files,
9261 which also allows single instance storage for them. Other backends
9262 don't support this for now.
9264 WARNING: This feature hasn't been tested much yet. Use at your own risk.
9266 Directory root where to store mail attachments. Disabled, if empty.
9267 Defaults to @samp{""}.
9270 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
9271 Attachments smaller than this aren't saved externally. It's also
9272 possible to write a plugin to disable saving specific attachments
9274 Defaults to @samp{128000}.
9277 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
9278 Filesystem backend to use for saving attachments:
9281 No SiS done by Dovecot (but this might help FS's own deduplication)
9283 SiS with immediate byte-by-byte comparison during saving
9284 @item sis-queue posix
9285 SiS with delayed comparison and deduplication.
9287 Defaults to @samp{"sis posix"}.
9290 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
9291 Hash format to use in attachment filenames. You can add any text and
9292 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
9293 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
9294 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
9295 Defaults to @samp{"%@{sha1@}"}.
9298 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
9300 Defaults to @samp{100}.
9303 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
9305 Defaults to @samp{1000}.
9308 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
9309 Default VSZ (virtual memory size) limit for service processes.
9310 This is mainly intended to catch and kill processes that leak memory
9311 before they eat up everything.
9312 Defaults to @samp{256000000}.
9315 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
9316 Login user is internally used by login processes. This is the most
9317 untrusted user in Dovecot system. It shouldn't have access to anything
9319 Defaults to @samp{"dovenull"}.
9322 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
9323 Internal user is used by unprivileged processes. It should be
9324 separate from login user, so that login processes can't disturb other
9326 Defaults to @samp{"dovecot"}.
9329 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
9330 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
9331 Defaults to @samp{"required"}.
9334 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
9335 PEM encoded X.509 SSL/TLS certificate (public key).
9336 Defaults to @samp{"</etc/dovecot/default.pem"}.
9339 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
9340 PEM encoded SSL/TLS private key. The key is opened before
9341 dropping root privileges, so keep the key file unreadable by anyone but
9343 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
9346 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
9347 If key file is password protected, give the password here.
9348 Alternatively give it when starting dovecot with -p parameter. Since
9349 this file is often world-readable, you may want to place this setting
9350 instead to a different.
9351 Defaults to @samp{""}.
9354 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
9355 PEM encoded trusted certificate authority. Set this only if you
9356 intend to use @samp{ssl-verify-client-cert? #t}. The file should
9357 contain the CA certificate(s) followed by the matching
9358 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
9359 Defaults to @samp{""}.
9362 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
9363 Require that CRL check succeeds for client certificates.
9364 Defaults to @samp{#t}.
9367 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
9368 Request client to send a certificate. If you also want to require
9369 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
9370 Defaults to @samp{#f}.
9373 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
9374 Which field from certificate to use for username. commonName and
9375 x500UniqueIdentifier are the usual choices. You'll also need to set
9376 @samp{auth-ssl-username-from-cert? #t}.
9377 Defaults to @samp{"commonName"}.
9380 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
9381 How often to regenerate the SSL parameters file. Generation is
9382 quite CPU intensive operation. The value is in hours, 0 disables
9383 regeneration entirely.
9384 Defaults to @samp{168}.
9387 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
9388 SSL protocols to use.
9389 Defaults to @samp{"!SSLv2"}.
9392 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
9394 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
9397 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
9398 SSL crypto device to use, for valid values run "openssl engine".
9399 Defaults to @samp{""}.
9402 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
9403 Address to use when sending rejection mails.
9404 Default is postmaster@@<your domain>. %d expands to recipient domain.
9405 Defaults to @samp{""}.
9408 @deftypevr {@code{dovecot-configuration} parameter} string hostname
9409 Hostname to use in various parts of sent mails (e.g. in Message-Id)
9410 and in LMTP replies. Default is the system's real hostname@@domain.
9411 Defaults to @samp{""}.
9414 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
9415 If user is over quota, return with temporary failure instead of
9417 Defaults to @samp{#f}.
9420 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
9421 Binary to use for sending mails.
9422 Defaults to @samp{"/usr/sbin/sendmail"}.
9425 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
9426 If non-empty, send mails via this SMTP host[:port] instead of
9428 Defaults to @samp{""}.
9431 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
9432 Subject: header to use for rejection mails. You can use the same
9433 variables as for @samp{rejection-reason} below.
9434 Defaults to @samp{"Rejected: %s"}.
9437 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
9438 Human readable error message for rejection mails. You can use
9451 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
9454 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
9455 Delimiter character between local-part and detail in email
9457 Defaults to @samp{"+"}.
9460 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
9461 Header where the original recipient address (SMTP's RCPT TO:
9462 address) is taken from if not available elsewhere. With dovecot-lda -a
9463 parameter overrides this. A commonly used header for this is
9465 Defaults to @samp{""}.
9468 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
9469 Should saving a mail to a nonexistent mailbox automatically create
9471 Defaults to @samp{#f}.
9474 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
9475 Should automatically created mailboxes be also automatically
9477 Defaults to @samp{#f}.
9480 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
9481 Maximum IMAP command line length. Some clients generate very long
9482 command lines with huge mailboxes, so you may need to raise this if you
9483 get "Too long argument" or "IMAP command line too large" errors
9485 Defaults to @samp{64000}.
9488 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
9489 IMAP logout format string:
9492 total number of bytes read from client
9494 total number of bytes sent to client.
9496 Defaults to @samp{"in=%i out=%o"}.
9499 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
9500 Override the IMAP CAPABILITY response. If the value begins with '+',
9501 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
9502 Defaults to @samp{""}.
9505 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
9506 How long to wait between "OK Still here" notifications when client
9508 Defaults to @samp{"2 mins"}.
9511 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
9512 ID field names and values to send to clients. Using * as the value
9513 makes Dovecot use the default value. The following fields have default
9514 values currently: name, version, os, os-version, support-url,
9516 Defaults to @samp{""}.
9519 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
9520 ID fields sent by client to log. * means everything.
9521 Defaults to @samp{""}.
9524 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
9525 Workarounds for various client bugs:
9529 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
9530 CHECK commands. Some clients ignore them otherwise, for example OSX
9531 Mail (<v2.1). Outlook Express breaks more badly though, without this it
9532 may show user "Message no longer in server" errors. Note that OE6
9533 still breaks even with this workaround if synchronization is set to
9536 @item tb-extra-mailbox-sep
9537 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
9538 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
9539 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
9542 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
9543 This makes Thunderbird realize they aren't selectable and show them
9544 greyed out, instead of only later giving "not selectable" popup error.
9546 Defaults to @samp{()}.
9549 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
9550 Host allowed in URLAUTH URLs sent by client. "*" allows all.
9551 Defaults to @samp{""}.
9555 Whew! Lots of configuration options. The nice thing about it though is
9556 that GuixSD has a complete interface to Dovecot's configuration
9557 language. This allows not only a nice way to declare configurations,
9558 but also offers reflective capabilities as well: users can write code to
9559 inspect and transform configurations from within Scheme.
9561 However, it could be that you just want to get a @code{dovecot.conf} up
9562 and running. In that case, you can pass an
9563 @code{opaque-dovecot-configuration} as the @code{#:config} paramter to
9564 @code{dovecot-service}. As its name indicates, an opaque configuration
9565 does not have easy reflective capabilities.
9567 Available @code{opaque-dovecot-configuration} fields are:
9569 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
9570 The dovecot package.
9573 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
9574 The contents of the @code{dovecot.conf}, as a string.
9577 For example, if your @code{dovecot.conf} is just the empty string, you
9578 could instantiate a dovecot service like this:
9581 (dovecot-service #:config
9582 (opaque-dovecot-configuration
9587 @subsubsection Web Services
9589 The @code{(gnu services web)} module provides the following service:
9591 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
9592 [#:log-directory ``/var/log/nginx''] @
9593 [#:run-directory ``/var/run/nginx''] @
9596 Return a service that runs @var{nginx}, the nginx web server.
9598 The nginx daemon loads its runtime configuration from @var{config-file}.
9599 Log files are written to @var{log-directory} and temporary runtime data
9600 files are written to @var{run-directory}. For proper operation, these
9601 arguments should match what is in @var{config-file} to ensure that the
9602 directories are created when the service is activated.
9606 @node Various Services
9607 @subsubsection Various Services
9609 The @code{(gnu services lirc)} module provides the following service.
9611 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
9612 [#:device #f] [#:driver #f] [#:config-file #f] @
9613 [#:extra-options '()]
9614 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
9615 decodes infrared signals from remote controls.
9617 Optionally, @var{device}, @var{driver} and @var{config-file}
9618 (configuration file name) may be specified. See @command{lircd} manual
9621 Finally, @var{extra-options} is a list of additional command-line options
9622 passed to @command{lircd}.
9625 @subsubsection Dictionary Services
9626 The @code{(gnu services dict)} module provides the following service:
9628 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
9629 Return a service that runs the @command{dicod} daemon, an implementation
9630 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
9632 The optional @var{config} argument specifies the configuration for
9633 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
9634 default it serves the GNU Collaborative International Dictonary of English.
9636 You can add @command{open localhost} to your @file{~/.dico} file to make
9637 @code{localhost} the default server for @command{dico} client
9638 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
9641 @deftp {Data Type} dicod-configuration
9642 Data type representing the configuration of dicod.
9645 @item @code{dico} (default: @var{dico})
9646 Package object of the GNU Dico dictionary server.
9648 @item @code{interfaces} (default: @var{'("localhost")})
9649 This is the list of IP addresses and ports and possibly socket file
9650 names to listen to (@pxref{Server Settings, @code{listen} directive,,
9651 dico, GNU Dico Manual}).
9653 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
9654 List of @code{<dicod-database>} objects denoting dictionaries to be served.
9658 @deftp {Data Type} dicod-database
9659 Data type representing a dictionary database.
9663 Name of the database, will be used in DICT commands.
9666 Name of the dicod module used by this database
9667 (@pxref{Modules,,, dico, GNU Dico Manual}).
9669 @item @code{options}
9670 List of strings or gexps representing the arguments for the module handler
9671 (@pxref{Handlers,,, dico, GNU Dico Manual}).
9675 @defvr {Scheme Variable} %dicod-database:gcide
9676 A @code{<dicod-database>} object serving the GNU Collaborative International
9677 Dictonary of English using the @code{gcide} package.
9680 @node Setuid Programs
9681 @subsection Setuid Programs
9683 @cindex setuid programs
9684 Some programs need to run with ``root'' privileges, even when they are
9685 launched by unprivileged users. A notorious example is the
9686 @command{passwd} program, which users can run to change their
9687 password, and which needs to access the @file{/etc/passwd} and
9688 @file{/etc/shadow} files---something normally restricted to root, for
9689 obvious security reasons. To address that, these executables are
9690 @dfn{setuid-root}, meaning that they always run with root privileges
9691 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
9692 for more info about the setuid mechanism.)
9694 The store itself @emph{cannot} contain setuid programs: that would be a
9695 security issue since any user on the system can write derivations that
9696 populate the store (@pxref{The Store}). Thus, a different mechanism is
9697 used: instead of changing the setuid bit directly on files that are in
9698 the store, we let the system administrator @emph{declare} which programs
9699 should be setuid root.
9701 The @code{setuid-programs} field of an @code{operating-system}
9702 declaration contains a list of G-expressions denoting the names of
9703 programs to be setuid-root (@pxref{Using the Configuration System}).
9704 For instance, the @command{passwd} program, which is part of the Shadow
9705 package, can be designated by this G-expression (@pxref{G-Expressions}):
9708 #~(string-append #$shadow "/bin/passwd")
9711 A default set of setuid programs is defined by the
9712 @code{%setuid-programs} variable of the @code{(gnu system)} module.
9714 @defvr {Scheme Variable} %setuid-programs
9715 A list of G-expressions denoting common programs that are setuid-root.
9717 The list includes commands such as @command{passwd}, @command{ping},
9718 @command{su}, and @command{sudo}.
9721 Under the hood, the actual setuid programs are created in the
9722 @file{/run/setuid-programs} directory at system activation time. The
9723 files in this directory refer to the ``real'' binaries, which are in the
9726 @node X.509 Certificates
9727 @subsection X.509 Certificates
9729 @cindex HTTPS, certificates
9730 @cindex X.509 certificates
9732 Web servers available over HTTPS (that is, HTTP over the transport-layer
9733 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
9734 that the client can then use to @emph{authenticate} the server. To do
9735 that, clients verify that the server's certificate is signed by a
9736 so-called @dfn{certificate authority} (CA). But to verify the CA's
9737 signature, clients must have first acquired the CA's certificate.
9739 Web browsers such as GNU@tie{}IceCat include their own set of CA
9740 certificates, such that they are able to verify CA signatures
9743 However, most other programs that can talk HTTPS---@command{wget},
9744 @command{git}, @command{w3m}, etc.---need to be told where CA
9745 certificates can be found.
9747 @cindex @code{nss-certs}
9748 In GuixSD, this is done by adding a package that provides certificates
9749 to the @code{packages} field of the @code{operating-system} declaration
9750 (@pxref{operating-system Reference}). GuixSD includes one such package,
9751 @code{nss-certs}, which is a set of CA certificates provided as part of
9752 Mozilla's Network Security Services.
9754 Note that it is @emph{not} part of @var{%base-packages}, so you need to
9755 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
9756 most applications and libraries look for certificates by default, points
9757 to the certificates installed globally.
9759 Unprivileged users, including users of Guix on a foreign distro,
9760 can also install their own certificate package in
9761 their profile. A number of environment variables need to be defined so
9762 that applications and libraries know where to find them. Namely, the
9763 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
9764 variables. Some applications add their own environment variables; for
9765 instance, the Git version control system honors the certificate bundle
9766 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
9767 would typically run something like:
9770 $ guix package -i nss-certs
9771 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
9772 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
9773 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
9776 @node Name Service Switch
9777 @subsection Name Service Switch
9779 @cindex name service switch
9781 The @code{(gnu system nss)} module provides bindings to the
9782 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
9783 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
9784 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
9785 extended with new ``name'' lookup methods for system databases, which
9786 includes host names, service names, user accounts, and more (@pxref{Name
9787 Service Switch, System Databases and Name Service Switch,, libc, The GNU
9788 C Library Reference Manual}).
9790 The NSS configuration specifies, for each system database, which lookup
9791 method is to be used, and how the various methods are chained
9792 together---for instance, under which circumstances NSS should try the
9793 next method in the list. The NSS configuration is given in the
9794 @code{name-service-switch} field of @code{operating-system} declarations
9795 (@pxref{operating-system Reference, @code{name-service-switch}}).
9798 @cindex .local, host name lookup
9799 As an example, the declaration below configures the NSS to use the
9800 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
9801 back-end}, which supports host name lookups over multicast DNS (mDNS)
9802 for host names ending in @code{.local}:
9805 (name-service-switch
9806 (hosts (list %files ;first, check /etc/hosts
9808 ;; If the above did not succeed, try
9809 ;; with 'mdns_minimal'.
9811 (name "mdns_minimal")
9813 ;; 'mdns_minimal' is authoritative for
9814 ;; '.local'. When it returns "not found",
9815 ;; no need to try the next methods.
9816 (reaction (lookup-specification
9817 (not-found => return))))
9819 ;; Then fall back to DNS.
9823 ;; Finally, try with the "full" 'mdns'.
9828 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
9829 contains this configuration, so you will not have to type it if all you
9830 want is to have @code{.local} host lookup working.
9832 Note that, in this case, in addition to setting the
9833 @code{name-service-switch} of the @code{operating-system} declaration,
9834 you also need to use @code{avahi-service} (@pxref{Networking Services,
9835 @code{avahi-service}}), or @var{%desktop-services}, which includes it
9836 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
9837 to the name service cache daemon (@pxref{Base Services,
9838 @code{nscd-service}}).
9840 For convenience, the following variables provide typical NSS
9843 @defvr {Scheme Variable} %default-nss
9844 This is the default name service switch configuration, a
9845 @code{name-service-switch} object.
9848 @defvr {Scheme Variable} %mdns-host-lookup-nss
9849 This is the name service switch configuration with support for host name
9850 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
9853 The reference for name service switch configuration is given below. It
9854 is a direct mapping of the configuration file format of the C library , so
9855 please refer to the C library manual for more information (@pxref{NSS
9856 Configuration File,,, libc, The GNU C Library Reference Manual}).
9857 Compared to the configuration file format of libc NSS, it has the advantage
9858 not only of adding this warm parenthetic feel that we like, but also
9859 static checks: you will know about syntax errors and typos as soon as you
9860 run @command{guix system}.
9862 @deftp {Data Type} name-service-switch
9864 This is the data type representation the configuration of libc's name
9865 service switch (NSS). Each field below represents one of the supported
9882 The system databases handled by the NSS. Each of these fields must be a
9883 list of @code{<name-service>} objects (see below).
9887 @deftp {Data Type} name-service
9889 This is the data type representing an actual name service and the
9890 associated lookup action.
9894 A string denoting the name service (@pxref{Services in the NSS
9895 configuration,,, libc, The GNU C Library Reference Manual}).
9897 Note that name services listed here must be visible to nscd. This is
9898 achieved by passing the @code{#:name-services} argument to
9899 @code{nscd-service} the list of packages providing the needed name
9900 services (@pxref{Base Services, @code{nscd-service}}).
9903 An action specified using the @code{lookup-specification} macro
9904 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
9905 Reference Manual}). For example:
9908 (lookup-specification (unavailable => continue)
9909 (success => return))
9914 @node Initial RAM Disk
9915 @subsection Initial RAM Disk
9917 @cindex initial RAM disk (initrd)
9918 @cindex initrd (initial RAM disk)
9919 For bootstrapping purposes, the Linux-Libre kernel is passed an
9920 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
9921 root file system as well as an initialization script. The latter is
9922 responsible for mounting the real root file system, and for loading any
9923 kernel modules that may be needed to achieve that.
9925 The @code{initrd} field of an @code{operating-system} declaration allows
9926 you to specify which initrd you would like to use. The @code{(gnu
9927 system linux-initrd)} module provides two ways to build an initrd: the
9928 high-level @code{base-initrd} procedure, and the low-level
9929 @code{expression->initrd} procedure.
9931 The @code{base-initrd} procedure is intended to cover most common uses.
9932 For example, if you want to add a bunch of kernel modules to be loaded
9933 at boot time, you can define the @code{initrd} field of the operating
9934 system declaration like this:
9937 (initrd (lambda (file-systems . rest)
9938 ;; Create a standard initrd that has modules "foo.ko"
9939 ;; and "bar.ko", as well as their dependencies, in
9940 ;; addition to the modules available by default.
9941 (apply base-initrd file-systems
9942 #:extra-modules '("foo" "bar")
9946 The @code{base-initrd} procedure also handles common use cases that
9947 involves using the system as a QEMU guest, or as a ``live'' system with
9948 volatile root file system.
9950 The initial RAM disk produced by @code{base-initrd} honors several
9951 options passed on the Linux kernel command line (that is, arguments
9952 passed @i{via} the @code{linux} command of GRUB, or the
9953 @code{-append} option) of QEMU, notably:
9956 @item --load=@var{boot}
9957 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
9958 program, once it has mounted the root file system.
9960 GuixSD uses this option to yield control to a boot program that runs the
9961 service activation programs and then spawns the GNU@tie{}Shepherd, the
9962 initialization system.
9964 @item --root=@var{root}
9965 Mount @var{root} as the root file system. @var{root} can be a
9966 device name like @code{/dev/sda1}, a partition label, or a partition
9969 @item --system=@var{system}
9970 Have @file{/run/booted-system} and @file{/run/current-system} point to
9973 @item modprobe.blacklist=@var{modules}@dots{}
9974 @cindex module, black-listing
9975 @cindex black list, of kernel modules
9976 Instruct the initial RAM disk as well as the @command{modprobe} command
9977 (from the kmod package) to refuse to load @var{modules}. @var{modules}
9978 must be a comma-separated list of module names---e.g.,
9979 @code{usbkbd,9pnet}.
9982 Start a read-eval-print loop (REPL) from the initial RAM disk before it
9983 tries to load kernel modules and to mount the root file system. Our
9984 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
9985 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
9986 Manual}, for more information on Guile's REPL.
9990 Now that you know all the features that initial RAM disks produced by
9991 @code{base-initrd} provide, here is how to use it and customize it
9994 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
9995 [#:qemu-networking? #f] [#:virtio? #t] [#:volatile-root? #f] @
9996 [#:extra-modules '()] [#:mapped-devices '()]
9997 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
9998 a list of file systems to be mounted by the initrd, possibly in addition to
9999 the root file system specified on the kernel command line via @code{--root}.
10000 @var{mapped-devices} is a list of device mappings to realize before
10001 @var{file-systems} are mounted (@pxref{Mapped Devices}).
10003 When @var{qemu-networking?} is true, set up networking with the standard QEMU
10004 parameters. When @var{virtio?} is true, load additional modules so that the
10005 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
10007 When @var{volatile-root?} is true, the root file system is writable but any changes
10010 The initrd is automatically populated with all the kernel modules necessary
10011 for @var{file-systems} and for the given options. However, additional kernel
10012 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
10013 loaded at boot time in the order in which they appear.
10016 Needless to say, the initrds we produce and use embed a
10017 statically-linked Guile, and the initialization program is a Guile
10018 program. That gives a lot of flexibility. The
10019 @code{expression->initrd} procedure builds such an initrd, given the
10020 program to run in that initrd.
10022 @deffn {Monadic Procedure} expression->initrd @var{exp} @
10023 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
10024 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
10025 containing @var{guile} and that evaluates @var{exp}, a G-expression,
10026 upon booting. All the derivations referenced by @var{exp} are
10027 automatically copied to the initrd.
10030 @node GRUB Configuration
10031 @subsection GRUB Configuration
10034 @cindex boot loader
10036 The operating system uses GNU@tie{}GRUB as its boot loader
10037 (@pxref{Overview, overview of GRUB,, grub, GNU GRUB Manual}). It is
10038 configured using a @code{grub-configuration} declaration. This data type
10039 is exported by the @code{(gnu system grub)} module and described below.
10041 @deftp {Data Type} grub-configuration
10042 The type of a GRUB configuration declaration.
10046 @item @code{device}
10047 This is a string denoting the boot device. It must be a device name
10048 understood by the @command{grub-install} command, such as
10049 @code{/dev/sda} or @code{(hd0)} (@pxref{Invoking grub-install,,, grub,
10052 @item @code{menu-entries} (default: @code{()})
10053 A possibly empty list of @code{menu-entry} objects (see below), denoting
10054 entries to appear in the GRUB boot menu, in addition to the current
10055 system entry and the entry pointing to previous system generations.
10057 @item @code{default-entry} (default: @code{0})
10058 The index of the default boot menu entry. Index 0 is for the entry of the
10061 @item @code{timeout} (default: @code{5})
10062 The number of seconds to wait for keyboard input before booting. Set to
10063 0 to boot immediately, and to -1 to wait indefinitely.
10065 @item @code{theme} (default: @var{%default-theme})
10066 The @code{grub-theme} object describing the theme to use.
10071 Should you want to list additional boot menu entries @i{via} the
10072 @code{menu-entries} field above, you will need to create them with the
10073 @code{menu-entry} form:
10075 @deftp {Data Type} menu-entry
10076 The type of an entry in the GRUB boot menu.
10081 The label to show in the menu---e.g., @code{"GNU"}.
10084 The Linux kernel to boot.
10086 @item @code{linux-arguments} (default: @code{()})
10087 The list of extra Linux kernel command-line arguments---e.g.,
10088 @code{("console=ttyS0")}.
10090 @item @code{initrd}
10091 A G-Expression or string denoting the file name of the initial RAM disk
10092 to use (@pxref{G-Expressions}).
10097 @c FIXME: Write documentation once it's stable.
10098 Themes are created using the @code{grub-theme} form, which is not
10101 @defvr {Scheme Variable} %default-theme
10102 This is the default GRUB theme used by the operating system, with a
10103 fancy background image displaying the GNU and Guix logos.
10107 @node Invoking guix system
10108 @subsection Invoking @code{guix system}
10110 Once you have written an operating system declaration as seen in the
10111 previous section, it can be @dfn{instantiated} using the @command{guix
10112 system} command. The synopsis is:
10115 guix system @var{options}@dots{} @var{action} @var{file}
10118 @var{file} must be the name of a file containing an
10119 @code{operating-system} declaration. @var{action} specifies how the
10120 operating system is instantiated. Currently the following values are
10125 Build the operating system described in @var{file}, activate it, and
10126 switch to it@footnote{This action is usable only on systems already
10129 This effects all the configuration specified in @var{file}: user
10130 accounts, system services, global package list, setuid programs, etc.
10131 The command starts system services specified in @var{file} that are not
10132 currently running; if a service is currently running, it does not
10133 attempt to upgrade it since this would not be possible without stopping it
10136 It also adds a GRUB menu entry for the new OS configuration, and moves
10137 entries for older configurations to a submenu---unless
10138 @option{--no-grub} is passed.
10141 @c The paragraph below refers to the problem discussed at
10142 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
10143 It is highly recommended to run @command{guix pull} once before you run
10144 @command{guix system reconfigure} for the first time (@pxref{Invoking
10145 guix pull}). Failing to do that you would see an older version of Guix
10146 once @command{reconfigure} has completed.
10150 Build the derivation of the operating system, which includes all the
10151 configuration files and programs needed to boot and run the system.
10152 This action does not actually install anything.
10155 Populate the given directory with all the files necessary to run the
10156 operating system specified in @var{file}. This is useful for first-time
10157 installations of GuixSD. For instance:
10160 guix system init my-os-config.scm /mnt
10163 copies to @file{/mnt} all the store items required by the configuration
10164 specified in @file{my-os-config.scm}. This includes configuration
10165 files, packages, and so on. It also creates other essential files
10166 needed for the system to operate correctly---e.g., the @file{/etc},
10167 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
10169 This command also installs GRUB on the device specified in
10170 @file{my-os-config}, unless the @option{--no-grub} option was passed.
10173 @cindex virtual machine
10175 @anchor{guix system vm}
10176 Build a virtual machine that contains the operating system declared in
10177 @var{file}, and return a script to run that virtual machine (VM).
10178 Arguments given to the script are passed to QEMU.
10180 The VM shares its store with the host system.
10182 Additional file systems can be shared between the host and the VM using
10183 the @code{--share} and @code{--expose} command-line options: the former
10184 specifies a directory to be shared with write access, while the latter
10185 provides read-only access to the shared directory.
10187 The example below creates a VM in which the user's home directory is
10188 accessible read-only, and where the @file{/exchange} directory is a
10189 read-write mapping of @file{$HOME/tmp} on the host:
10192 guix system vm my-config.scm \
10193 --expose=$HOME --share=$HOME/tmp=/exchange
10196 On GNU/Linux, the default is to boot directly to the kernel; this has
10197 the advantage of requiring only a very tiny root disk image since the
10198 store of the host can then be mounted.
10200 The @code{--full-boot} option forces a complete boot sequence, starting
10201 with the bootloader. This requires more disk space since a root image
10202 containing at least the kernel, initrd, and bootloader data files must
10203 be created. The @code{--image-size} option can be used to specify the
10208 Return a virtual machine or disk image of the operating system declared
10209 in @var{file} that stands alone. Use the @option{--image-size} option
10210 to specify the size of the image.
10212 When using @code{vm-image}, the returned image is in qcow2 format, which
10213 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
10214 for more information on how to run the image in a virtual machine.
10216 When using @code{disk-image}, a raw disk image is produced; it can be
10217 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
10218 the device corresponding to a USB stick, one can copy the image to it
10219 using the following command:
10222 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
10226 Return a script to run the operating system declared in @var{file}
10227 within a container. Containers are a set of lightweight isolation
10228 mechanisms provided by the kernel Linux-libre. Containers are
10229 substantially less resource-demanding than full virtual machines since
10230 the kernel, shared objects, and other resources can be shared with the
10231 host system; this also means they provide thinner isolation.
10233 Currently, the script must be run as root in order to support more than
10234 a single user and group. The container shares its store with the host
10237 As with the @code{vm} action (@pxref{guix system vm}), additional file
10238 systems to be shared between the host and container can be specified
10239 using the @option{--share} and @option{--expose} options:
10242 guix system container my-config.scm \
10243 --expose=$HOME --share=$HOME/tmp=/exchange
10247 This option requires Linux-libre 3.19 or newer.
10252 @var{options} can contain any of the common build options (@pxref{Common
10253 Build Options}). In addition, @var{options} can contain one of the
10257 @item --system=@var{system}
10258 @itemx -s @var{system}
10259 Attempt to build for @var{system} instead of the host system type.
10260 This works as per @command{guix build} (@pxref{Invoking guix build}).
10264 Return the derivation file name of the given operating system without
10267 @item --image-size=@var{size}
10268 For the @code{vm-image} and @code{disk-image} actions, create an image
10269 of the given @var{size}. @var{size} may be a number of bytes, or it may
10270 include a unit as a suffix (@pxref{Block size, size specifications,,
10271 coreutils, GNU Coreutils}).
10273 @item --on-error=@var{strategy}
10274 Apply @var{strategy} when an error occurs when reading @var{file}.
10275 @var{strategy} may be one of the following:
10278 @item nothing-special
10279 Report the error concisely and exit. This is the default strategy.
10282 Likewise, but also display a backtrace.
10285 Report the error and enter Guile's debugger. From there, you can run
10286 commands such as @code{,bt} to get a backtrace, @code{,locals} to
10287 display local variable values, and more generally inspect the state of the
10288 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
10289 a list of available debugging commands.
10294 All the actions above, except @code{build} and @code{init},
10295 can use KVM support in the Linux-libre kernel. Specifically, if the
10296 machine has hardware virtualization support, the corresponding
10297 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
10298 must exist and be readable and writable by the user and by the
10299 build users of the daemon (@pxref{Build Environment Setup}).
10302 Once you have built, configured, re-configured, and re-re-configured
10303 your GuixSD installation, you may find it useful to list the operating
10304 system generations available on disk---and that you can choose from the
10309 @item list-generations
10310 List a summary of each generation of the operating system available on
10311 disk, in a human-readable way. This is similar to the
10312 @option{--list-generations} option of @command{guix package}
10313 (@pxref{Invoking guix package}).
10315 Optionally, one can specify a pattern, with the same syntax that is used
10316 in @command{guix package --list-generations}, to restrict the list of
10317 generations displayed. For instance, the following command displays
10318 generations that are up to 10 days old:
10321 $ guix system list-generations 10d
10326 The @command{guix system} command has even more to offer! The following
10327 sub-commands allow you to visualize how your system services relate to
10330 @anchor{system-extension-graph}
10333 @item extension-graph
10334 Emit in Dot/Graphviz format to standard output the @dfn{service
10335 extension graph} of the operating system defined in @var{file}
10336 (@pxref{Service Composition}, for more information on service
10342 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
10345 produces a PDF file showing the extension relations among services.
10347 @anchor{system-shepherd-graph}
10348 @item shepherd-graph
10349 Emit in Dot/Graphviz format to standard output the @dfn{dependency
10350 graph} of shepherd services of the operating system defined in
10351 @var{file}. @xref{Shepherd Services}, for more information and for an
10356 @node Running GuixSD in a VM
10357 @subsection Running GuixSD in a Virtual Machine
10359 One way to run GuixSD in a virtual machine (VM) is to build a GuixSD
10360 virtual machine image using @command{guix system vm-image}
10361 (@pxref{Invoking guix system}). The returned image is in qcow2 format,
10362 which the @uref{http://qemu.org/, QEMU emulator} can efficiently use.
10364 To run the image in QEMU, copy it out of the store (@pxref{The Store})
10365 and give yourself permission to write to the copy. When invoking QEMU,
10366 you must choose a system emulator that is suitable for your hardware
10367 platform. Here is a minimal QEMU invocation that will boot the result
10368 of @command{guix system vm-image} on x86_64 hardware:
10371 $ qemu-system-x86_64 \
10372 -net user -net nic,model=virtio \
10373 -enable-kvm -m 256 /tmp/qemu-image
10376 Here is what each of these options means:
10379 @item qemu-system-x86_64
10380 This specifies the hardware platform to emulate. This should match the
10384 Enable the unprivileged user-mode network stack. The guest OS can
10385 access the host but not vice versa. This is the simplest way to get the
10386 guest OS online. If you do not choose a network stack, the boot will
10389 @item -net nic,model=virtio
10390 You must create a network interface of a given model. If you do not
10391 create a NIC, the boot will fail. Assuming your hardware platform is
10392 x86_64, you can get a list of available NIC models by running
10393 @command{qemu-system-x86_64 -net nic,model=help}.
10396 If your system has hardware virtualization extensions, enabling the
10397 virtual machine support (KVM) of the Linux kernel will make things run
10401 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
10402 which may be insufficent for some operations.
10404 @item /tmp/qemu-image
10405 The file name of the qcow2 image.
10408 @node Defining Services
10409 @subsection Defining Services
10411 The previous sections show the available services and how one can combine
10412 them in an @code{operating-system} declaration. But how do we define
10413 them in the first place? And what is a service anyway?
10416 * Service Composition:: The model for composing services.
10417 * Service Types and Services:: Types and services.
10418 * Service Reference:: API reference.
10419 * Shepherd Services:: A particular type of service.
10422 @node Service Composition
10423 @subsubsection Service Composition
10427 Here we define a @dfn{service} as, broadly, something that extends the
10428 functionality of the operating system. Often a service is a process---a
10429 @dfn{daemon}---started when the system boots: a secure shell server, a
10430 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
10431 whose execution can be triggered by another daemon---e.g., an FTP server
10432 started by @command{inetd} or a D-Bus service activated by
10433 @command{dbus-daemon}. Occasionally, a service does not map to a
10434 daemon. For instance, the ``account'' service collects user accounts
10435 and makes sure they exist when the system runs; the ``udev'' service
10436 collects device management rules and makes them available to the eudev
10437 daemon; the @file{/etc} service populates the @file{/etc} directory
10440 @cindex service extensions
10441 GuixSD services are connected by @dfn{extensions}. For instance, the
10442 secure shell service @emph{extends} the Shepherd---the GuixSD
10443 initialization system, running as PID@tie{}1---by giving it the command
10444 lines to start and stop the secure shell daemon (@pxref{Networking
10445 Services, @code{lsh-service}}); the UPower service extends the D-Bus
10446 service by passing it its @file{.service} specification, and extends the
10447 udev service by passing it device management rules (@pxref{Desktop
10448 Services, @code{upower-service}}); the Guix daemon service extends the
10449 Shepherd by passing it the command lines to start and stop the daemon,
10450 and extends the account service by passing it a list of required build
10451 user accounts (@pxref{Base Services}).
10453 All in all, services and their ``extends'' relations form a directed
10454 acyclic graph (DAG). If we represent services as boxes and extensions
10455 as arrows, a typical system might provide something like this:
10457 @image{images/service-graph,,5in,Typical service extension graph.}
10459 @cindex system service
10460 At the bottom, we see the @dfn{system service}, which produces the
10461 directory containing everything to run and boot the system, as returned
10462 by the @command{guix system build} command. @xref{Service Reference},
10463 to learn about the other service types shown here.
10464 @xref{system-extension-graph, the @command{guix system extension-graph}
10465 command}, for information on how to generate this representation for a
10466 particular operating system definition.
10468 @cindex service types
10469 Technically, developers can define @dfn{service types} to express these
10470 relations. There can be any number of services of a given type on the
10471 system---for instance, a system running two instances of the GNU secure
10472 shell server (lsh) has two instances of @var{lsh-service-type}, with
10473 different parameters.
10475 The following section describes the programming interface for service
10476 types and services.
10478 @node Service Types and Services
10479 @subsubsection Service Types and Services
10481 A @dfn{service type} is a node in the DAG described above. Let us start
10482 with a simple example, the service type for the Guix build daemon
10483 (@pxref{Invoking guix-daemon}):
10486 (define guix-service-type
10490 (list (service-extension shepherd-root-service-type guix-shepherd-service)
10491 (service-extension account-service-type guix-accounts)
10492 (service-extension activation-service-type guix-activation)))))
10496 It defines two things:
10500 A name, whose sole purpose is to make inspection and debugging easier.
10503 A list of @dfn{service extensions}, where each extension designates the
10504 target service type and a procedure that, given the parameters of the
10505 service, returns a list of objects to extend the service of that type.
10507 Every service type has at least one service extension. The only
10508 exception is the @dfn{boot service type}, which is the ultimate service.
10511 In this example, @var{guix-service-type} extends three services:
10514 @item shepherd-root-service-type
10515 The @var{guix-shepherd-service} procedure defines how the Shepherd
10516 service is extended. Namely, it returns a @code{<shepherd-service>}
10517 object that defines how @command{guix-daemon} is started and stopped
10518 (@pxref{Shepherd Services}).
10520 @item account-service-type
10521 This extension for this service is computed by @var{guix-accounts},
10522 which returns a list of @code{user-group} and @code{user-account}
10523 objects representing the build user accounts (@pxref{Invoking
10526 @item activation-service-type
10527 Here @var{guix-activation} is a procedure that returns a gexp, which is
10528 a code snippet to run at ``activation time''---e.g., when the service is
10532 A service of this type is instantiated like this:
10535 (service guix-service-type
10536 (guix-configuration
10538 (use-substitutes? #f)))
10541 The second argument to the @code{service} form is a value representing
10542 the parameters of this specific service instance.
10543 @xref{guix-configuration-type, @code{guix-configuration}}, for
10544 information about the @code{guix-configuration} data type.
10546 @var{guix-service-type} is quite simple because it extends other
10547 services but is not extensible itself.
10549 @c @subsubsubsection Extensible Service Types
10551 The service type for an @emph{extensible} service looks like this:
10554 (define udev-service-type
10555 (service-type (name 'udev)
10557 (list (service-extension shepherd-root-service-type
10558 udev-shepherd-service)))
10560 (compose concatenate) ;concatenate the list of rules
10561 (extend (lambda (config rules)
10563 (($ <udev-configuration> udev initial-rules)
10564 (udev-configuration
10565 (udev udev) ;the udev package to use
10566 (rules (append initial-rules rules)))))))))
10569 This is the service type for the
10570 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
10571 management daemon}. Compared to the previous example, in addition to an
10572 extension of @var{shepherd-root-service-type}, we see two new fields:
10576 This is the procedure to @dfn{compose} the list of extensions to
10577 services of this type.
10579 Services can extend the udev service by passing it lists of rules; we
10580 compose those extensions simply by concatenating them.
10583 This procedure defines how the value of the service is @dfn{extended} with
10584 the composition of the extensions.
10586 Udev extensions are composed into a list of rules, but the udev service
10587 value is itself a @code{<udev-configuration>} record. So here, we
10588 extend that record by appending the list of rules it contains to the
10589 list of contributed rules.
10592 There can be only one instance of an extensible service type such as
10593 @var{udev-service-type}. If there were more, the
10594 @code{service-extension} specifications would be ambiguous.
10596 Still here? The next section provides a reference of the programming
10597 interface for services.
10599 @node Service Reference
10600 @subsubsection Service Reference
10602 We have seen an overview of service types (@pxref{Service Types and
10603 Services}). This section provides a reference on how to manipulate
10604 services and service types. This interface is provided by the
10605 @code{(gnu services)} module.
10607 @deffn {Scheme Procedure} service @var{type} @var{value}
10608 Return a new service of @var{type}, a @code{<service-type>} object (see
10609 below.) @var{value} can be any object; it represents the parameters of
10610 this particular service instance.
10613 @deffn {Scheme Procedure} service? @var{obj}
10614 Return true if @var{obj} is a service.
10617 @deffn {Scheme Procedure} service-kind @var{service}
10618 Return the type of @var{service}---i.e., a @code{<service-type>} object.
10621 @deffn {Scheme Procedure} service-parameters @var{service}
10622 Return the value associated with @var{service}. It represents its
10626 Here is an example of how a service is created and manipulated:
10630 (service nginx-service-type
10631 (nginx-configuration
10633 (log-directory log-directory)
10634 (run-directory run-directory)
10635 (file config-file))))
10640 (eq? (service-kind s) nginx-service-type)
10644 The @code{modify-services} form provides a handy way to change the
10645 parameters of some of the services of a list such as
10646 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
10647 evalutes to a list of services. Of course, you could always use
10648 standard list combinators such as @code{map} and @code{fold} to do that
10649 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
10650 @code{modify-services} simply provides a more concise form for this
10653 @deffn {Scheme Syntax} modify-services @var{services} @
10654 (@var{type} @var{variable} => @var{body}) @dots{}
10656 Modify the services listed in @var{services} according to the given
10657 clauses. Each clause has the form:
10660 (@var{type} @var{variable} => @var{body})
10663 where @var{type} is a service type---e.g.,
10664 @code{guix-service-type}---and @var{variable} is an identifier that is
10665 bound within the @var{body} to the service parameters---e.g., a
10666 @code{guix-configuration} instance---of the original service of that
10669 The @var{body} should evaluate to the new service parameters, which will
10670 be used to configure the new service. This new service will replace the
10671 original in the resulting list. Because a service's service parameters
10672 are created using @code{define-record-type*}, you can write a succint
10673 @var{body} that evaluates to the new service parameters by using the
10674 @code{inherit} feature that @code{define-record-type*} provides.
10676 @xref{Using the Configuration System}, for example usage.
10680 Next comes the programming interface for service types. This is
10681 something you want to know when writing new service definitions, but not
10682 necessarily when simply looking for ways to customize your
10683 @code{operating-system} declaration.
10685 @deftp {Data Type} service-type
10686 @cindex service type
10687 This is the representation of a @dfn{service type} (@pxref{Service Types
10692 This is a symbol, used only to simplify inspection and debugging.
10694 @item @code{extensions}
10695 A non-empty list of @code{<service-extension>} objects (see below).
10697 @item @code{compose} (default: @code{#f})
10698 If this is @code{#f}, then the service type denotes services that cannot
10699 be extended---i.e., services that do not receive ``values'' from other
10702 Otherwise, it must be a one-argument procedure. The procedure is called
10703 by @code{fold-services} and is passed a list of values collected from
10704 extensions. It must return a value that is a valid parameter value for
10705 the service instance.
10707 @item @code{extend} (default: @code{#f})
10708 If this is @code{#f}, services of this type cannot be extended.
10710 Otherwise, it must be a two-argument procedure: @code{fold-services}
10711 calls it, passing it the initial value of the service as the first argument
10712 and the result of applying @code{compose} to the extension values as the
10716 @xref{Service Types and Services}, for examples.
10719 @deffn {Scheme Procedure} service-extension @var{target-type} @
10721 Return a new extension for services of type @var{target-type}.
10722 @var{compute} must be a one-argument procedure: @code{fold-services}
10723 calls it, passing it the value associated with the service that provides
10724 the extension; it must return a valid value for the target service.
10727 @deffn {Scheme Procedure} service-extension? @var{obj}
10728 Return true if @var{obj} is a service extension.
10731 At the core of the service abstraction lies the @code{fold-services}
10732 procedure, which is responsible for ``compiling'' a list of services
10733 down to a single directory that contains everything needed to boot and
10734 run the system---the directory shown by the @command{guix system build}
10735 command (@pxref{Invoking guix system}). In essence, it propagates
10736 service extensions down the service graph, updating each node parameters
10737 on the way, until it reaches the root node.
10739 @deffn {Scheme Procedure} fold-services @var{services} @
10740 [#:target-type @var{system-service-type}]
10741 Fold @var{services} by propagating their extensions down to the root of
10742 type @var{target-type}; return the root service adjusted accordingly.
10745 Lastly, the @code{(gnu services)} module also defines several essential
10746 service types, some of which are listed below.
10748 @defvr {Scheme Variable} system-service-type
10749 This is the root of the service graph. It produces the system directory
10750 as returned by the @command{guix system build} command.
10753 @defvr {Scheme Variable} boot-service-type
10754 The type of the ``boot service'', which produces the @dfn{boot script}.
10755 The boot script is what the initial RAM disk runs when booting.
10758 @defvr {Scheme Variable} etc-service-type
10759 The type of the @file{/etc} service. This service can be extended by
10760 passing it name/file tuples such as:
10763 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
10766 In this example, the effect would be to add an @file{/etc/issue} file
10767 pointing to the given file.
10770 @defvr {Scheme Variable} setuid-program-service-type
10771 Type for the ``setuid-program service''. This service collects lists of
10772 executable file names, passed as gexps, and adds them to the set of
10773 setuid-root programs on the system (@pxref{Setuid Programs}).
10776 @defvr {Scheme Variable} profile-service-type
10777 Type of the service that populates the @dfn{system profile}---i.e., the
10778 programs under @file{/run/current-system/profile}. Other services can
10779 extend it by passing it lists of packages to add to the system profile.
10783 @node Shepherd Services
10784 @subsubsection Shepherd Services
10787 @cindex init system
10788 The @code{(gnu services shepherd)} module provides a way to define
10789 services managed by the GNU@tie{}Shepherd, which is the GuixSD
10790 initialization system---the first process that is started when the
10791 system boots, also known as PID@tie{}1
10792 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
10794 Services in the Shepherd can depend on each other. For instance, the
10795 SSH daemon may need to be started after the syslog daemon has been
10796 started, which in turn can only happen once all the file systems have
10797 been mounted. The simple operating system defined earlier (@pxref{Using
10798 the Configuration System}) results in a service graph like this:
10800 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
10802 You can actually generate such a graph for any operating system
10803 definition using the @command{guix system shepherd-graph} command
10804 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
10806 The @var{%shepherd-root-service} is a service object representing
10807 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
10808 by passing it lists of @code{<shepherd-service>} objects.
10810 @deftp {Data Type} shepherd-service
10811 The data type representing a service managed by the Shepherd.
10814 @item @code{provision}
10815 This is a list of symbols denoting what the service provides.
10817 These are the names that may be passed to @command{herd start},
10818 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
10819 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
10820 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
10822 @item @code{requirements} (default: @code{'()})
10823 List of symbols denoting the Shepherd services this one depends on.
10825 @item @code{respawn?} (default: @code{#t})
10826 Whether to restart the service when it stops, for instance when the
10827 underlying process dies.
10830 @itemx @code{stop} (default: @code{#~(const #f)})
10831 The @code{start} and @code{stop} fields refer to the Shepherd's
10832 facilities to start and stop processes (@pxref{Service De- and
10833 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
10834 G-expressions that get expanded in the Shepherd configuration file
10835 (@pxref{G-Expressions}).
10837 @item @code{documentation}
10838 A documentation string, as shown when running:
10841 herd doc @var{service-name}
10844 where @var{service-name} is one of the symbols in @var{provision}
10845 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
10847 @item @code{modules} (default: @var{%default-modules})
10848 This is the list of modules that must be in scope when @code{start} and
10849 @code{stop} are evaluated.
10851 @item @code{imported-modules} (default: @var{%default-imported-modules})
10852 This is the list of modules to import in the execution environment of
10858 @defvr {Scheme Variable} shepherd-root-service-type
10859 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
10861 This is the service type that extensions target when they want to create
10862 shepherd services (@pxref{Service Types and Services}, for an example).
10863 Each extension must pass a list of @code{<shepherd-service>}.
10866 @defvr {Scheme Variable} %shepherd-root-service
10867 This service represents PID@tie{}1.
10871 @node Installing Debugging Files
10872 @section Installing Debugging Files
10874 @cindex debugging files
10875 Program binaries, as produced by the GCC compilers for instance, are
10876 typically written in the ELF format, with a section containing
10877 @dfn{debugging information}. Debugging information is what allows the
10878 debugger, GDB, to map binary code to source code; it is required to
10879 debug a compiled program in good conditions.
10881 The problem with debugging information is that is takes up a fair amount
10882 of disk space. For example, debugging information for the GNU C Library
10883 weighs in at more than 60 MiB. Thus, as a user, keeping all the
10884 debugging info of all the installed programs is usually not an option.
10885 Yet, space savings should not come at the cost of an impediment to
10886 debugging---especially in the GNU system, which should make it easier
10887 for users to exert their computing freedom (@pxref{GNU Distribution}).
10889 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
10890 mechanism that allows users to get the best of both worlds: debugging
10891 information can be stripped from the binaries and stored in separate
10892 files. GDB is then able to load debugging information from those files,
10893 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
10896 The GNU distribution takes advantage of this by storing debugging
10897 information in the @code{lib/debug} sub-directory of a separate package
10898 output unimaginatively called @code{debug} (@pxref{Packages with
10899 Multiple Outputs}). Users can choose to install the @code{debug} output
10900 of a package when they need it. For instance, the following command
10901 installs the debugging information for the GNU C Library and for GNU
10905 guix package -i glibc:debug guile:debug
10908 GDB must then be told to look for debug files in the user's profile, by
10909 setting the @code{debug-file-directory} variable (consider setting it
10910 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
10914 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
10917 From there on, GDB will pick up debugging information from the
10918 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
10920 In addition, you will most likely want GDB to be able to show the source
10921 code being debugged. To do that, you will have to unpack the source
10922 code of the package of interest (obtained with @code{guix build
10923 --source}, @pxref{Invoking guix build}), and to point GDB to that source
10924 directory using the @code{directory} command (@pxref{Source Path,
10925 @code{directory},, gdb, Debugging with GDB}).
10927 @c XXX: keep me up-to-date
10928 The @code{debug} output mechanism in Guix is implemented by the
10929 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
10930 opt-in---debugging information is available only for the packages
10931 with definitions explicitly declaring a @code{debug} output. This may be
10932 changed to opt-out in the future if our build farm servers can handle
10933 the load. To check whether a package has a @code{debug} output, use
10934 @command{guix package --list-available} (@pxref{Invoking guix package}).
10937 @node Security Updates
10938 @section Security Updates
10940 @cindex security updates
10941 @cindex security vulnerabilities
10942 Occasionally, important security vulnerabilities are discovered in software
10943 packages and must be patched. Guix developers try hard to keep track of
10944 known vulnerabilities and to apply fixes as soon as possible in the
10945 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
10946 containing only security updates.) The @command{guix lint} tool helps
10947 developers find out about vulnerable versions of software packages in the
10952 gnu/packages/base.scm:652:2: glibc-2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
10953 gnu/packages/gcc.scm:334:2: gcc-4.9.3: probably vulnerable to CVE-2015-5276
10954 gnu/packages/image.scm:312:2: openjpeg-2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
10958 @xref{Invoking guix lint}, for more information.
10961 As of version @value{VERSION}, the feature described below is considered
10965 Guix follows a functional
10966 package management discipline (@pxref{Introduction}), which implies
10967 that, when a package is changed, @emph{every package that depends on it}
10968 must be rebuilt. This can significantly slow down the deployment of
10969 fixes in core packages such as libc or Bash, since basically the whole
10970 distribution would need to be rebuilt. Using pre-built binaries helps
10971 (@pxref{Substitutes}), but deployment may still take more time than
10975 To address this, Guix implements @dfn{grafts}, a mechanism that allows
10976 for fast deployment of critical updates without the costs associated
10977 with a whole-distribution rebuild. The idea is to rebuild only the
10978 package that needs to be patched, and then to ``graft'' it onto packages
10979 explicitly installed by the user and that were previously referring to
10980 the original package. The cost of grafting is typically very low, and
10981 order of magnitudes lower than a full rebuild of the dependency chain.
10983 @cindex replacements of packages, for grafts
10984 For instance, suppose a security update needs to be applied to Bash.
10985 Guix developers will provide a package definition for the ``fixed''
10986 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
10987 Packages}). Then, the original package definition is augmented with a
10988 @code{replacement} field pointing to the package containing the bug fix:
10995 (replacement bash-fixed)))
10998 From there on, any package depending directly or indirectly on Bash---as
10999 reported by @command{guix gc --requisites} (@pxref{Invoking guix
11000 gc})---that is installed is automatically ``rewritten'' to refer to
11001 @var{bash-fixed} instead of @var{bash}. This grafting process takes
11002 time proportional to the size of the package, usually less than a
11003 minute for an ``average'' package on a recent machine. Grafting is
11004 recursive: when an indirect dependency requires grafting, then grafting
11005 ``propagates'' up to the package that the user is installing.
11007 Currently, the graft and the package it replaces (@var{bash-fixed} and
11008 @var{bash} in the example above) must have the exact same @code{name}
11009 and @code{version} fields. This restriction mostly comes from the fact
11010 that grafting works by patching files, including binary files, directly.
11011 Other restrictions may apply: for instance, when adding a graft to a
11012 package providing a shared library, the original shared library and its
11013 replacement must have the same @code{SONAME} and be binary-compatible.
11015 The @option{--no-grafts} command-line option allows you to forcefully
11016 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
11020 guix build bash --no-grafts
11024 returns the store file name of the original Bash, whereas:
11031 returns the store file name of the ``fixed'', replacement Bash. This
11032 allows you to distinguish between the two variants of Bash.
11034 To verify which Bash your whole profile refers to, you can run
11035 (@pxref{Invoking guix gc}):
11038 guix gc -R `readlink -f ~/.guix-profile` | grep bash
11042 @dots{} and compare the store file names that you get with those above.
11043 Likewise for a complete GuixSD system generation:
11046 guix gc -R `guix system build my-config.scm` | grep bash
11049 Lastly, to check which Bash running processes are using, you can use the
11050 @command{lsof} command:
11053 lsof | grep /gnu/store/.*bash
11057 @node Package Modules
11058 @section Package Modules
11060 From a programming viewpoint, the package definitions of the
11061 GNU distribution are provided by Guile modules in the @code{(gnu packages
11062 @dots{})} name space@footnote{Note that packages under the @code{(gnu
11063 packages @dots{})} module name space are not necessarily ``GNU
11064 packages''. This module naming scheme follows the usual Guile module
11065 naming convention: @code{gnu} means that these modules are distributed
11066 as part of the GNU system, and @code{packages} identifies modules that
11067 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
11068 Reference Manual}). For instance, the @code{(gnu packages emacs)}
11069 module exports a variable named @code{emacs}, which is bound to a
11070 @code{<package>} object (@pxref{Defining Packages}).
11072 The @code{(gnu packages @dots{})} module name space is
11073 automatically scanned for packages by the command-line tools. For
11074 instance, when running @code{guix package -i emacs}, all the @code{(gnu
11075 packages @dots{})} modules are scanned until one that exports a package
11076 object whose name is @code{emacs} is found. This package search
11077 facility is implemented in the @code{(gnu packages)} module.
11079 @cindex customization, of packages
11080 @cindex package module search path
11081 Users can store package definitions in modules with different
11082 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
11083 name and module name must match. For instance, the @code{(my-packages
11084 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
11085 relative to the load path specified with @option{--load-path} or
11086 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
11087 guile, GNU Guile Reference Manual}, for details.}. These package definitions
11088 will not be visible by default. Users can invoke commands such as
11089 @command{guix package} and @command{guix build} with the
11090 @code{-e} option so that they know where to find the package. Better
11091 yet, they can use the
11092 @code{-L} option of these commands to make those modules visible
11093 (@pxref{Invoking guix build, @code{--load-path}}), or define the
11094 @code{GUIX_PACKAGE_PATH} environment variable. This environment
11095 variable makes it easy to extend or customize the distribution and is
11096 honored by all the user interfaces.
11098 @defvr {Environment Variable} GUIX_PACKAGE_PATH
11099 This is a colon-separated list of directories to search for additional
11100 package modules. Directories listed in this variable take precedence
11101 over the own modules of the distribution.
11104 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
11105 each package is built based solely on other packages in the
11106 distribution. The root of this dependency graph is a small set of
11107 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
11108 bootstrap)} module. For more information on bootstrapping,
11109 @pxref{Bootstrapping}.
11111 @node Packaging Guidelines
11112 @section Packaging Guidelines
11114 The GNU distribution is nascent and may well lack some of your favorite
11115 packages. This section describes how you can help make the distribution
11116 grow. @xref{Contributing}, for additional information on how you can
11119 Free software packages are usually distributed in the form of
11120 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
11121 all the source files. Adding a package to the distribution means
11122 essentially two things: adding a @dfn{recipe} that describes how to
11123 build the package, including a list of other packages required to build
11124 it, and adding @dfn{package metadata} along with that recipe, such as a
11125 description and licensing information.
11127 In Guix all this information is embodied in @dfn{package definitions}.
11128 Package definitions provide a high-level view of the package. They are
11129 written using the syntax of the Scheme programming language; in fact,
11130 for each package we define a variable bound to the package definition,
11131 and export that variable from a module (@pxref{Package Modules}).
11132 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
11133 creating packages. For more information on package definitions,
11134 @pxref{Defining Packages}.
11136 Once a package definition is in place, stored in a file in the Guix
11137 source tree, it can be tested using the @command{guix build} command
11138 (@pxref{Invoking guix build}). For example, assuming the new package is
11139 called @code{gnew}, you may run this command from the Guix build tree
11140 (@pxref{Running Guix Before It Is Installed}):
11143 ./pre-inst-env guix build gnew --keep-failed
11146 Using @code{--keep-failed} makes it easier to debug build failures since
11147 it provides access to the failed build tree. Another useful
11148 command-line option when debugging is @code{--log-file}, to access the
11151 If the package is unknown to the @command{guix} command, it may be that
11152 the source file contains a syntax error, or lacks a @code{define-public}
11153 clause to export the package variable. To figure it out, you may load
11154 the module from Guile to get more information about the actual error:
11157 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
11160 Once your package builds correctly, please send us a patch
11161 (@pxref{Contributing}). Well, if you need help, we will be happy to
11162 help you too. Once the patch is committed in the Guix repository, the
11163 new package automatically gets built on the supported platforms by
11164 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
11167 @cindex substituter
11168 Users can obtain the new package definition simply by running
11169 @command{guix pull} (@pxref{Invoking guix pull}). When
11170 @code{hydra.gnu.org} is done building the package, installing the
11171 package automatically downloads binaries from there
11172 (@pxref{Substitutes}). The only place where human intervention is
11173 needed is to review and apply the patch.
11177 * Software Freedom:: What may go into the distribution.
11178 * Package Naming:: What's in a name?
11179 * Version Numbers:: When the name is not enough.
11180 * Synopses and Descriptions:: Helping users find the right package.
11181 * Python Modules:: Taming the snake.
11182 * Perl Modules:: Little pearls.
11183 * Java Packages:: Coffee break.
11184 * Fonts:: Fond of fonts.
11187 @node Software Freedom
11188 @subsection Software Freedom
11190 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
11192 The GNU operating system has been developed so that users can have
11193 freedom in their computing. GNU is @dfn{free software}, meaning that
11194 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
11195 essential freedoms}: to run the program, to study and change the program
11196 in source code form, to redistribute exact copies, and to distribute
11197 modified versions. Packages found in the GNU distribution provide only
11198 software that conveys these four freedoms.
11200 In addition, the GNU distribution follow the
11201 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
11202 software distribution guidelines}. Among other things, these guidelines
11203 reject non-free firmware, recommendations of non-free software, and
11204 discuss ways to deal with trademarks and patents.
11206 Some otherwise free upstream package sources contain a small and optional
11207 subset that violates the above guidelines, for instance because this subset
11208 is itself non-free code. When that happens, the offending items are removed
11209 with appropriate patches or code snippets in the @code{origin} form of the
11210 package (@pxref{Defining Packages}). This way, @code{guix
11211 build --source} returns the ``freed'' source rather than the unmodified
11215 @node Package Naming
11216 @subsection Package Naming
11218 A package has actually two names associated with it:
11219 First, there is the name of the @emph{Scheme variable}, the one following
11220 @code{define-public}. By this name, the package can be made known in the
11221 Scheme code, for instance as input to another package. Second, there is
11222 the string in the @code{name} field of a package definition. This name
11223 is used by package management commands such as
11224 @command{guix package} and @command{guix build}.
11226 Both are usually the same and correspond to the lowercase conversion of
11227 the project name chosen upstream, with underscores replaced with
11228 hyphens. For instance, GNUnet is available as @code{gnunet}, and
11229 SDL_net as @code{sdl-net}.
11231 We do not add @code{lib} prefixes for library packages, unless these are
11232 already part of the official project name. But @pxref{Python
11233 Modules} and @ref{Perl Modules} for special rules concerning modules for
11234 the Python and Perl languages.
11236 Font package names are handled differently, @pxref{Fonts}.
11239 @node Version Numbers
11240 @subsection Version Numbers
11242 We usually package only the latest version of a given free software
11243 project. But sometimes, for instance for incompatible library versions,
11244 two (or more) versions of the same package are needed. These require
11245 different Scheme variable names. We use the name as defined
11246 in @ref{Package Naming}
11247 for the most recent version; previous versions use the same name, suffixed
11248 by @code{-} and the smallest prefix of the version number that may
11249 distinguish the two versions.
11251 The name inside the package definition is the same for all versions of a
11252 package and does not contain any version number.
11254 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
11257 (define-public gtk+
11262 (define-public gtk+-2
11265 (version "2.24.20")
11268 If we also wanted GTK+ 3.8.2, this would be packaged as
11270 (define-public gtk+-3.8
11277 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
11278 @c for a discussion of what follows.
11279 @cindex version number, for VCS snapshots
11280 Occasionally, we package snapshots of upstream's version control system
11281 (VCS) instead of formal releases. This should remain exceptional,
11282 because it is up to upstream developers to clarify what the stable
11283 release is. Yet, it is sometimes necessary. So, what should we put in
11284 the @code{version} field?
11286 Clearly, we need to make the commit identifier of the VCS snapshot
11287 visible in the version string, but we also need to make sure that the
11288 version string is monotonically increasing so that @command{guix package
11289 --upgrade} can determine which version is newer. Since commit
11290 identifiers, notably with Git, are not monotonically increasing, we add
11291 a revision number that we increase each time we upgrade to a newer
11292 snapshot. The resulting version string looks like this:
11297 | | `-- upstream commit ID
11299 | `--- Guix package revision
11301 latest upstream version
11304 It is a good idea to strip commit identifiers in the @code{version}
11305 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
11306 aesthetics have a role to play here) as well as problems related to OS
11307 limits such as the maximum shebang length (127 bytes for the Linux
11308 kernel.) It is best to use the full commit identifiers in
11309 @code{origin}s, though, to avoid ambiguities. A typical package
11310 definition may look like this:
11314 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7"))
11316 (version (string-append "0.9-1."
11317 (string-take commit 7)))
11320 (uri (git-reference
11321 (url "git://example.org/my-package.git")
11323 (sha256 (base32 "1mbikn@dots{}"))
11324 (file-name (string-append "my-package-" version
11330 @node Synopses and Descriptions
11331 @subsection Synopses and Descriptions
11333 As we have seen before, each package in GNU@tie{}Guix includes a
11334 synopsis and a description (@pxref{Defining Packages}). Synopses and
11335 descriptions are important: They are what @command{guix package
11336 --search} searches, and a crucial piece of information to help users
11337 determine whether a given package suits their needs. Consequently,
11338 packagers should pay attention to what goes into them.
11340 Synopses must start with a capital letter and must not end with a
11341 period. They must not start with ``a'' or ``the'', which usually does
11342 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
11343 tool that frobs files''. The synopsis should say what the package
11344 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
11345 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
11346 matching a pattern''.
11348 Keep in mind that the synopsis must be meaningful for a very wide
11349 audience. For example, ``Manipulate alignments in the SAM format''
11350 might make sense for a seasoned bioinformatics researcher, but might be
11351 fairly unhelpful or even misleading to a non-specialized audience. It
11352 is a good idea to come up with a synopsis that gives an idea of the
11353 application domain of the package. In this example, this might give
11354 something like ``Manipulate nucleotide sequence alignments'', which
11355 hopefully gives the user a better idea of whether this is what they are
11358 Descriptions should take between five and ten lines. Use full
11359 sentences, and avoid using acronyms without first introducing them.
11360 Please avoid marketing phrases such as ``world-leading'',
11361 ``industrial-strength'', and ``next-generation'', and avoid superlatives
11362 like ``the most advanced''---they are not helpful to users looking for a
11363 package and may even sound suspicious. Instead, try to be factual,
11364 mentioning use cases and features.
11366 @cindex Texinfo markup, in package descriptions
11367 Descriptions can include Texinfo markup, which is useful to introduce
11368 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
11369 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
11370 should be careful when using some characters for example @samp{@@} and
11371 curly braces which are the basic special characters in Texinfo
11372 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
11373 such as @command{guix package --show} take care of rendering it
11376 Synopses and descriptions are translated by volunteers
11377 @uref{http://translationproject.org/domain/guix-packages.html, at the
11378 Translation Project} so that as many users as possible can read them in
11379 their native language. User interfaces search them and display them in
11380 the language specified by the current locale.
11382 Translation is a lot of work so, as a packager, please pay even more
11383 attention to your synopses and descriptions as every change may entail
11384 additional work for translators. In order to help them, it is possible
11385 to make recommendations or instructions visible to them by inserting
11386 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
11390 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
11391 (description "ARandR is designed to provide a simple visual front end
11392 for the X11 resize-and-rotate (RandR) extension. @dots{}")
11396 @node Python Modules
11397 @subsection Python Modules
11399 We currently package Python 2 and Python 3, under the Scheme variable names
11400 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
11401 To avoid confusion and naming clashes with other programming languages, it
11402 seems desirable that the name of a package for a Python module contains
11403 the word @code{python}.
11405 Some modules are compatible with only one version of Python, others with both.
11406 If the package Foo compiles only with Python 3, we name it
11407 @code{python-foo}; if it compiles only with Python 2, we name it
11408 @code{python2-foo}. If it is compatible with both versions, we create two
11409 packages with the corresponding names.
11411 If a project already contains the word @code{python}, we drop this;
11412 for instance, the module python-dateutil is packaged under the names
11413 @code{python-dateutil} and @code{python2-dateutil}. If the project name
11414 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
11419 @subsection Perl Modules
11421 Perl programs standing for themselves are named as any other package,
11422 using the lowercase upstream name.
11423 For Perl packages containing a single class, we use the lowercase class name,
11424 replace all occurrences of @code{::} by dashes and prepend the prefix
11426 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
11427 Modules containing several classes keep their lowercase upstream name and
11428 are also prepended by @code{perl-}. Such modules tend to have the word
11429 @code{perl} somewhere in their name, which gets dropped in favor of the
11430 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
11433 @node Java Packages
11434 @subsection Java Packages
11436 Java programs standing for themselves are named as any other package,
11437 using the lowercase upstream name.
11439 To avoid confusion and naming clashes with other programming languages,
11440 it is desirable that the name of a package for a Java package is
11441 prefixed with @code{java-}. If a project already contains the word
11442 @code{java}, we drop this; for instance, the package @code{ngsjava} is
11443 packaged under the name @code{java-ngs}.
11445 For Java packages containing a single class or a small class hierarchy,
11446 we use the lowercase class name, replace all occurrences of @code{.} by
11447 dashes and prepend the prefix @code{java-}. So the class
11448 @code{apache.commons.cli} becomes package
11449 @code{java-apache-commons-cli}.
11455 For fonts that are in general not installed by a user for typesetting
11456 purposes, or that are distributed as part of a larger software package,
11457 we rely on the general packaging rules for software; for instance, this
11458 applies to the fonts delivered as part of the X.Org system or fonts that
11459 are part of TeX Live.
11461 To make it easier for a user to search for fonts, names for other packages
11462 containing only fonts are constructed as follows, independently of the
11463 upstream package name.
11465 The name of a package containing only one font family starts with
11466 @code{font-}; it is followed by the foundry name and a dash @code{-}
11467 if the foundry is known, and the font family name, in which spaces are
11468 replaced by dashes (and as usual, all upper case letters are transformed
11470 For example, the Gentium font family by SIL is packaged under the name
11471 @code{font-sil-gentium}.
11473 For a package containing several font families, the name of the collection
11474 is used in the place of the font family name.
11475 For instance, the Liberation fonts consist of three families,
11476 Liberation Sans, Liberation Serif and Liberation Mono.
11477 These could be packaged separately under the names
11478 @code{font-liberation-sans} and so on; but as they are distributed together
11479 under a common name, we prefer to package them together as
11480 @code{font-liberation}.
11482 In the case where several formats of the same font family or font collection
11483 are packaged separately, a short form of the format, prepended by a dash,
11484 is added to the package name. We use @code{-ttf} for TrueType fonts,
11485 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
11490 @node Bootstrapping
11491 @section Bootstrapping
11493 @c Adapted from the ELS 2013 paper.
11495 @cindex bootstrapping
11497 Bootstrapping in our context refers to how the distribution gets built
11498 ``from nothing''. Remember that the build environment of a derivation
11499 contains nothing but its declared inputs (@pxref{Introduction}). So
11500 there's an obvious chicken-and-egg problem: how does the first package
11501 get built? How does the first compiler get compiled? Note that this is
11502 a question of interest only to the curious hacker, not to the regular
11503 user, so you can shamelessly skip this section if you consider yourself
11504 a ``regular user''.
11506 @cindex bootstrap binaries
11507 The GNU system is primarily made of C code, with libc at its core. The
11508 GNU build system itself assumes the availability of a Bourne shell and
11509 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
11510 `grep'. Furthermore, build programs---programs that run
11511 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
11512 (@pxref{Derivations}). Consequently, to be able to build anything at
11513 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
11514 Binutils, libc, and the other packages mentioned above---the
11515 @dfn{bootstrap binaries}.
11517 These bootstrap binaries are ``taken for granted'', though we can also
11518 re-create them if needed (more on that later).
11520 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
11522 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
11523 @c large image, it's hard to scroll. Oh well.
11524 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
11526 The figure above shows the very beginning of the dependency graph of the
11527 distribution, corresponding to the package definitions of the @code{(gnu
11528 packages bootstrap)} module. A similar figure can be generated with
11529 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
11532 guix graph -t derivation \
11533 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
11537 At this level of detail, things are
11538 slightly complex. First, Guile itself consists of an ELF executable,
11539 along with many source and compiled Scheme files that are dynamically
11540 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
11541 tarball shown in this graph. This tarball is part of Guix's ``source''
11542 distribution, and gets inserted into the store with @code{add-to-store}
11543 (@pxref{The Store}).
11545 But how do we write a derivation that unpacks this tarball and adds it
11546 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
11547 derivation---the first one that gets built---uses @code{bash} as its
11548 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
11549 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
11550 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
11551 the Guix source distribution, whose sole purpose is to allow the Guile
11552 tarball to be unpacked.
11554 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
11555 Guile that can be used to run subsequent build programs. Its first task
11556 is to download tarballs containing the other pre-built binaries---this
11557 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
11558 @code{ftp-client.scm} are used for this purpose. The
11559 @code{module-import.drv} derivations import those modules in a directory
11560 in the store, using the original layout. The
11561 @code{module-import-compiled.drv} derivations compile those modules, and
11562 write them in an output directory with the right layout. This
11563 corresponds to the @code{#:modules} argument of
11564 @code{build-expression->derivation} (@pxref{Derivations}).
11566 Finally, the various tarballs are unpacked by the
11567 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
11568 etc., at which point we have a working C tool chain.
11571 @unnumberedsubsec Building the Build Tools
11573 Bootstrapping is complete when we have a full tool chain that does not
11574 depend on the pre-built bootstrap tools discussed above. This
11575 no-dependency requirement is verified by checking whether the files of
11576 the final tool chain contain references to the @file{/gnu/store}
11577 directories of the bootstrap inputs. The process that leads to this
11578 ``final'' tool chain is described by the package definitions found in
11579 the @code{(gnu packages commencement)} module.
11581 The @command{guix graph} command allows us to ``zoom out'' compared to
11582 the graph above, by looking at the level of package objects instead of
11583 individual derivations---remember that a package may translate to
11584 several derivations, typically one derivation to download its source,
11585 one to build the Guile modules it needs, and one to actually build the
11586 package from source. The command:
11589 guix graph -t bag \
11590 -e '(@@@@ (gnu packages commencement)
11591 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
11595 produces the dependency graph leading to the ``final'' C
11596 library@footnote{You may notice the @code{glibc-intermediate} label,
11597 suggesting that it is not @emph{quite} final, but as a good
11598 approximation, we will consider it final.}, depicted below.
11600 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
11602 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
11603 The first tool that gets built with the bootstrap binaries is
11604 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
11605 for all the following packages. From there Findutils and Diffutils get
11608 Then come the first-stage Binutils and GCC, built as pseudo cross
11609 tools---i.e., with @code{--target} equal to @code{--host}. They are
11610 used to build libc. Thanks to this cross-build trick, this libc is
11611 guaranteed not to hold any reference to the initial tool chain.
11613 From there the final Binutils and GCC (not shown above) are built.
11615 from the final Binutils, and links programs against the just-built libc.
11616 This tool chain is used to build the other packages used by Guix and by
11617 the GNU Build System: Guile, Bash, Coreutils, etc.
11619 And voilà! At this point we have the complete set of build tools that
11620 the GNU Build System expects. These are in the @code{%final-inputs}
11621 variable of the @code{(gnu packages commencement)} module, and are
11622 implicitly used by any package that uses @code{gnu-build-system}
11623 (@pxref{Build Systems, @code{gnu-build-system}}).
11626 @unnumberedsubsec Building the Bootstrap Binaries
11628 Because the final tool chain does not depend on the bootstrap binaries,
11629 those rarely need to be updated. Nevertheless, it is useful to have an
11630 automated way to produce them, should an update occur, and this is what
11631 the @code{(gnu packages make-bootstrap)} module provides.
11633 The following command builds the tarballs containing the bootstrap
11634 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
11635 of Coreutils and other basic command-line tools):
11638 guix build bootstrap-tarballs
11641 The generated tarballs are those that should be referred to in the
11642 @code{(gnu packages bootstrap)} module mentioned at the beginning of
11645 Still here? Then perhaps by now you've started to wonder: when do we
11646 reach a fixed point? That is an interesting question! The answer is
11647 unknown, but if you would like to investigate further (and have
11648 significant computational and storage resources to do so), then let us
11652 @section Porting to a New Platform
11654 As discussed above, the GNU distribution is self-contained, and
11655 self-containment is achieved by relying on pre-built ``bootstrap
11656 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
11657 operating system kernel, CPU architecture, and application binary
11658 interface (ABI). Thus, to port the distribution to a platform that is
11659 not yet supported, one must build those bootstrap binaries, and update
11660 the @code{(gnu packages bootstrap)} module to use them on that platform.
11662 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
11663 When everything goes well, and assuming the GNU tool chain supports the
11664 target platform, this can be as simple as running a command like this
11668 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
11671 For this to work, the @code{glibc-dynamic-linker} procedure in
11672 @code{(gnu packages bootstrap)} must be augmented to return the right
11673 file name for libc's dynamic linker on that platform; likewise,
11674 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
11675 taught about the new platform.
11677 Once these are built, the @code{(gnu packages bootstrap)} module needs
11678 to be updated to refer to these binaries on the target platform. That
11679 is, the hashes and URLs of the bootstrap tarballs for the new platform
11680 must be added alongside those of the currently supported platforms. The
11681 bootstrap Guile tarball is treated specially: it is expected to be
11682 available locally, and @file{gnu/local.mk} has rules do download it for
11683 the supported architectures; a rule for the new platform must be added
11686 In practice, there may be some complications. First, it may be that the
11687 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
11688 above) is not recognized by all the GNU tools. Typically, glibc
11689 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
11690 configure flag (see @code{gcc.scm} for examples of how to handle this).
11691 Second, some of the required packages could fail to build for that
11692 platform. Lastly, the generated binaries could be broken for some
11695 @c *********************************************************************
11696 @include contributing.texi
11698 @c *********************************************************************
11699 @node Acknowledgments
11700 @chapter Acknowledgments
11702 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
11703 which was designed and
11704 implemented by Eelco Dolstra, with contributions from other people (see
11705 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
11706 management, and promoted unprecedented features, such as transactional
11707 package upgrades and rollbacks, per-user profiles, and referentially
11708 transparent build processes. Without this work, Guix would not exist.
11710 The Nix-based software distributions, Nixpkgs and NixOS, have also been
11711 an inspiration for Guix.
11713 GNU@tie{}Guix itself is a collective work with contributions from a
11714 number of people. See the @file{AUTHORS} file in Guix for more
11715 information on these fine people. The @file{THANKS} file lists people
11716 who have helped by reporting bugs, taking care of the infrastructure,
11717 providing artwork and themes, making suggestions, and more---thank you!
11720 @c *********************************************************************
11721 @node GNU Free Documentation License
11722 @appendix GNU Free Documentation License
11724 @include fdl-1.3.texi
11726 @c *********************************************************************
11727 @node Concept Index
11728 @unnumbered Concept Index
11731 @node Programming Index
11732 @unnumbered Programming Index
11733 @syncodeindex tp fn
11734 @syncodeindex vr fn
11739 @c Local Variables:
11740 @c ispell-local-dictionary: "american";