4258 lines
164 KiB
Plaintext
4258 lines
164 KiB
Plaintext
\input texinfo
|
||
@c -*-texinfo-*-
|
||
|
||
@c %**start of header
|
||
@setfilename guix.info
|
||
@documentencoding UTF-8
|
||
@settitle GNU Guix Reference Manual
|
||
@c %**end of header
|
||
|
||
@include version.texi
|
||
|
||
@copying
|
||
Copyright @copyright{} 2012, 2013, 2014 Ludovic Courtès@*
|
||
Copyright @copyright{} 2013, 2014 Andreas Enge@*
|
||
Copyright @copyright{} 2013 Nikita Karetnikov
|
||
|
||
Permission is granted to copy, distribute and/or modify this document
|
||
under the terms of the GNU Free Documentation License, Version 1.3 or
|
||
any later version published by the Free Software Foundation; with no
|
||
Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
|
||
copy of the license is included in the section entitled ``GNU Free
|
||
Documentation License''.
|
||
@end copying
|
||
|
||
@dircategory Package management
|
||
@direntry
|
||
* guix: (guix). Guix, the functional package manager.
|
||
* guix package: (guix)Invoking guix package
|
||
Managing packages with Guix.
|
||
* guix build: (guix)Invoking guix build
|
||
Building packages with Guix.
|
||
* guix system: (guix)Invoking guix system
|
||
Managing the operating system configuration.
|
||
@end direntry
|
||
|
||
@titlepage
|
||
@title GNU Guix Reference Manual
|
||
@subtitle Using the GNU Guix Functional Package Manager
|
||
@author Ludovic Courtès
|
||
@author Andreas Enge
|
||
@author Nikita Karetnikov
|
||
|
||
@page
|
||
@vskip 0pt plus 1filll
|
||
Edition @value{EDITION} @*
|
||
@value{UPDATED} @*
|
||
|
||
@insertcopying
|
||
@end titlepage
|
||
|
||
@contents
|
||
|
||
@c *********************************************************************
|
||
@node Top
|
||
@top GNU Guix
|
||
|
||
This document describes GNU Guix version @value{VERSION}, a functional
|
||
package management tool written for the GNU system.
|
||
|
||
@menu
|
||
* Introduction:: What is Guix about?
|
||
* Installation:: Installing Guix.
|
||
* Package Management:: Package installation, upgrade, etc.
|
||
* Programming Interface:: Using Guix in Scheme.
|
||
* Utilities:: Package management commands.
|
||
* GNU Distribution:: Software for your friendly GNU system.
|
||
* Contributing:: Your help needed!
|
||
|
||
* Acknowledgments:: Thanks!
|
||
* GNU Free Documentation License:: The license of this manual.
|
||
* Concept Index:: Concepts.
|
||
* Programming Index:: Data types, functions, and variables.
|
||
@end menu
|
||
|
||
@c *********************************************************************
|
||
@node Introduction
|
||
@chapter Introduction
|
||
|
||
GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
|
||
using the international phonetic alphabet (IPA).} is a functional
|
||
package management tool for the GNU system. Package management consists
|
||
of all activities that relate to building packages from sources,
|
||
honoring their build-time and run-time dependencies,
|
||
installing packages in user environments, upgrading installed packages
|
||
to new versions or rolling back to a previous set, removing unused
|
||
software packages, etc.
|
||
|
||
@cindex functional package management
|
||
The term @dfn{functional} refers to a specific package management
|
||
discipline. In Guix, the package build and installation process is seen
|
||
as a function, in the mathematical sense. That function takes inputs,
|
||
such as build scripts, a compiler, and libraries, and
|
||
returns an installed package. As a pure function, its result depends
|
||
solely on its inputs---for instance, it cannot refer to software or
|
||
scripts that were not explicitly passed as inputs. A build function
|
||
always produces the same result when passed a given set of inputs. It
|
||
cannot alter the system's environment in
|
||
any way; for instance, it cannot create, modify, or delete files outside
|
||
of its build and installation directories. This is achieved by running
|
||
build processes in isolated environments (or @dfn{containers}), where only their
|
||
explicit inputs are visible.
|
||
|
||
@cindex store
|
||
The result of package build functions is @dfn{cached} in the file
|
||
system, in a special directory called @dfn{the store} (@pxref{The
|
||
Store}). Each package is installed in a directory of its own, in the
|
||
store---by default under @file{/gnu/store}. The directory name contains
|
||
a hash of all the inputs used to build that package; thus, changing an
|
||
input yields a different directory name.
|
||
|
||
This approach is the foundation of Guix's salient features: support for
|
||
transactional package upgrade and rollback, per-user installation, and
|
||
garbage collection of packages (@pxref{Features}).
|
||
|
||
Guix has a command-line interface, which allows users to build, install,
|
||
upgrade, and remove packages, as well as a Scheme programming interface.
|
||
|
||
Last but not least, Guix is used to build a distribution of the GNU
|
||
system, with many GNU and non-GNU free software packages. @xref{GNU
|
||
Distribution}.
|
||
|
||
@c *********************************************************************
|
||
@node Installation
|
||
@chapter Installation
|
||
|
||
GNU Guix is available for download from its website at
|
||
@url{http://www.gnu.org/software/guix/}. This section describes the
|
||
software requirements of Guix, as well as how to install it and get
|
||
ready to use it.
|
||
|
||
Note that this section is concerned with the installation of the package
|
||
manager, which can be done on top of a running GNU/Linux system. If,
|
||
instead, you want to install the complete GNU operating system,
|
||
@pxref{System Installation}.
|
||
|
||
The build procedure for Guix is the same as for other GNU software, and
|
||
is not covered here. Please see the files @file{README} and
|
||
@file{INSTALL} in the Guix source tree for additional details.
|
||
|
||
@menu
|
||
* Requirements:: Software needed to build and run Guix.
|
||
* Setting Up the Daemon:: Preparing the build daemon's environment.
|
||
* Invoking guix-daemon:: Running the build daemon.
|
||
@end menu
|
||
|
||
@node Requirements
|
||
@section Requirements
|
||
|
||
GNU Guix depends on the following packages:
|
||
|
||
@itemize
|
||
@item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.5 or later;
|
||
@item @url{http://gnupg.org/, GNU libgcrypt}
|
||
@end itemize
|
||
|
||
Unless @code{--disable-daemon} was passed to @command{configure}, the
|
||
following packages are also needed:
|
||
|
||
@itemize
|
||
@item @url{http://sqlite.org, SQLite 3}
|
||
@item @url{http://www.bzip.org, libbz2}
|
||
@item @url{http://gcc.gnu.org, GCC's g++}
|
||
@end itemize
|
||
|
||
When a working installation of @url{http://nixos.org/nix/, the Nix package
|
||
manager} is available, you
|
||
can instead configure Guix with @code{--disable-daemon}. In that case,
|
||
Nix replaces the three dependencies above.
|
||
|
||
Guix is compatible with Nix, so it is possible to share the same store
|
||
between both. To do so, you must pass @command{configure} not only the
|
||
same @code{--with-store-dir} value, but also the same
|
||
@code{--localstatedir} value. The latter is essential because it
|
||
specifies where the database that stores metadata about the store is
|
||
located, among other things. The default values for Nix are
|
||
@code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
|
||
Note that @code{--disable-daemon} is not required if
|
||
your goal is to share the store with Nix.
|
||
|
||
@node Setting Up the Daemon
|
||
@section Setting Up the Daemon
|
||
|
||
@cindex daemon
|
||
Operations such as building a package or running the garbage collector
|
||
are all performed by a specialized process, the @dfn{build daemon}, on
|
||
behalf of clients. Only the daemon may access the store and its
|
||
associated database. Thus, any operation that manipulates the store
|
||
goes through the daemon. For instance, command-line tools such as
|
||
@command{guix package} and @command{guix build} communicate with the
|
||
daemon (@i{via} remote procedure calls) to instruct it what to do.
|
||
|
||
The following sections explain how to prepare the build daemon's
|
||
environment.
|
||
|
||
@menu
|
||
* Build Environment Setup:: Preparing the isolated build environment.
|
||
* Daemon Offload Setup:: Offloading builds to remote machines.
|
||
@end menu
|
||
|
||
@node Build Environment Setup
|
||
@subsection Build Environment Setup
|
||
|
||
In a standard multi-user setup, Guix and its daemon---the
|
||
@command{guix-daemon} program---are installed by the system
|
||
administrator; @file{/gnu/store} is owned by @code{root} and
|
||
@command{guix-daemon} runs as @code{root}. Unprivileged users may use
|
||
Guix tools to build packages or otherwise access the store, and the
|
||
daemon will do it on their behalf, ensuring that the store is kept in a
|
||
consistent state, and allowing built packages to be shared among users.
|
||
|
||
@cindex build users
|
||
When @command{guix-daemon} runs as @code{root}, you may not want package
|
||
build processes themselves to run as @code{root} too, for obvious
|
||
security reasons. To avoid that, a special pool of @dfn{build users}
|
||
should be created for use by build processes started by the daemon.
|
||
These build users need not have a shell and a home directory: they will
|
||
just be used when the daemon drops @code{root} privileges in build
|
||
processes. Having several such users allows the daemon to launch
|
||
distinct build processes under separate UIDs, which guarantees that they
|
||
do not interfere with each other---an essential feature since builds are
|
||
regarded as pure functions (@pxref{Introduction}).
|
||
|
||
On a GNU/Linux system, a build user pool may be created like this (using
|
||
Bash syntax and the @code{shadow} commands):
|
||
|
||
@c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
|
||
@c for why `-G' is needed.
|
||
@example
|
||
# groupadd guix-builder
|
||
# for i in `seq 1 10`;
|
||
do
|
||
useradd -g guix-builder -G guix-builder \
|
||
-d /var/empty -s `which nologin` \
|
||
-c "Guix build user $i" --system \
|
||
guix-builder$i;
|
||
done
|
||
@end example
|
||
|
||
@noindent
|
||
The @code{guix-daemon} program may then be run as @code{root} with:
|
||
|
||
@example
|
||
# guix-daemon --build-users-group=guix-builder
|
||
@end example
|
||
|
||
@cindex chroot
|
||
@noindent
|
||
This way, the daemon starts build processes in a chroot, under one of
|
||
the @code{guix-builder} users. On GNU/Linux, by default, the chroot
|
||
environment contains nothing but:
|
||
|
||
@c Keep this list in sync with libstore/build.cc! -----------------------
|
||
@itemize
|
||
@item
|
||
a minimal @code{/dev} directory, created mostly independently from the
|
||
host @code{/dev}@footnote{``Mostly'', because while the set of files
|
||
that appear in the chroot's @code{/dev} is fixed, most of these files
|
||
can only be created if the host has them.};
|
||
|
||
@item
|
||
the @code{/proc} directory; it only shows the container's processes
|
||
since a separate PID name space is used;
|
||
|
||
@item
|
||
@file{/etc/passwd} with an entry for the current user and an entry for
|
||
user @file{nobody};
|
||
|
||
@item
|
||
@file{/etc/group} with an entry for the user's group;
|
||
|
||
@item
|
||
@file{/etc/hosts} with an entry that maps @code{localhost} to
|
||
@code{127.0.0.1};
|
||
|
||
@item
|
||
a writable @file{/tmp} directory.
|
||
@end itemize
|
||
|
||
If you are installing Guix as an unprivileged user, it is still
|
||
possible to run @command{guix-daemon}. However, build processes will
|
||
not be isolated from one another, and not from the rest of the system.
|
||
Thus, build processes may interfere with each other, and may access
|
||
programs, libraries, and other files available on the system---making it
|
||
much harder to view them as @emph{pure} functions.
|
||
|
||
|
||
@node Daemon Offload Setup
|
||
@subsection Using the Offload Facility
|
||
|
||
@cindex offloading
|
||
@cindex build hook
|
||
When desired, the build daemon can @dfn{offload}
|
||
derivation builds to other machines
|
||
running Guix, using the @code{offload} @dfn{build hook}. When that
|
||
feature is enabled, a list of user-specified build machines is read from
|
||
@file{/etc/guix/machines.scm}; anytime a build is requested, for
|
||
instance via @code{guix build}, the daemon attempts to offload it to one
|
||
of the machines that satisfies the derivation's constraints, in
|
||
particular its system type---e.g., @file{x86_64-linux}. Missing
|
||
prerequisites for the build are copied over SSH to the target machine,
|
||
which then proceeds with the build; upon success the output(s) of the
|
||
build are copied back to the initial machine.
|
||
|
||
The @file{/etc/guix/machines.scm} file typically looks like this:
|
||
|
||
@example
|
||
(list (build-machine
|
||
(name "eightysix.example.org")
|
||
(system "x86_64-linux")
|
||
(user "bob")
|
||
(speed 2.)) ; incredibly fast!
|
||
|
||
(build-machine
|
||
(name "meeps.example.org")
|
||
(system "mips64el-linux")
|
||
(user "alice")
|
||
(private-key
|
||
(string-append (getenv "HOME")
|
||
"/.ssh/id-rsa-for-guix"))))
|
||
@end example
|
||
|
||
@noindent
|
||
In the example above we specify a list of two build machines, one for
|
||
the @code{x86_64} architecture and one for the @code{mips64el}
|
||
architecture.
|
||
|
||
In fact, this file is---not surprisingly!---a Scheme file that is
|
||
evaluated when the @code{offload} hook is started. Its return value
|
||
must be a list of @code{build-machine} objects. While this example
|
||
shows a fixed list of build machines, one could imagine, say, using
|
||
DNS-SD to return a list of potential build machines discovered in the
|
||
local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
|
||
Avahi in Guile Scheme Programs}).
|
||
|
||
The compulsory fields for a @code{build-machine} declaration are:
|
||
|
||
@table @code
|
||
|
||
@item name
|
||
The remote machine's host name.
|
||
|
||
@item system
|
||
The remote machine's system type.
|
||
|
||
@item user
|
||
The user account to use when connecting to the remote machine over SSH.
|
||
Note that the SSH key pair must @emph{not} be passphrase-protected, to
|
||
allow non-interactive logins.
|
||
|
||
@end table
|
||
|
||
@noindent
|
||
A number of optional fields may be specified:
|
||
|
||
@table @code
|
||
|
||
@item port
|
||
Port number of the machine's SSH server (default: 22).
|
||
|
||
@item private-key
|
||
The SSH private key file to use when connecting to the machine.
|
||
|
||
@item parallel-builds
|
||
The number of builds that may run in parallel on the machine (1 by
|
||
default.)
|
||
|
||
@item speed
|
||
A ``relative speed factor''. The offload scheduler will tend to prefer
|
||
machines with a higher speed factor.
|
||
|
||
@item features
|
||
A list of strings denoting specific features supported by the machine.
|
||
An example is @code{"kvm"} for machines that have the KVM Linux modules
|
||
and corresponding hardware support. Derivations can request features by
|
||
name, and they will be scheduled on matching build machines.
|
||
|
||
@end table
|
||
|
||
The @code{guix} command must be in the search path on the build
|
||
machines, since offloading works by invoking the @code{guix archive} and
|
||
@code{guix build} commands.
|
||
|
||
There's one last thing to do once @file{machines.scm} is in place. As
|
||
explained above, when offloading, files are transferred back and forth
|
||
between the machine stores. For this to work, you need to generate a
|
||
key pair to allow the daemon to export signed archives of files from the
|
||
store (@pxref{Invoking guix archive}):
|
||
|
||
@example
|
||
# guix archive --generate-key
|
||
@end example
|
||
|
||
@noindent
|
||
Thus, when receiving files, a machine's build daemon can make sure they
|
||
are genuine, have not been tampered with, and that they are signed by an
|
||
authorized key.
|
||
|
||
|
||
@node Invoking guix-daemon
|
||
@section Invoking @command{guix-daemon}
|
||
|
||
The @command{guix-daemon} program implements all the functionality to
|
||
access the store. This includes launching build processes, running the
|
||
garbage collector, querying the availability of a build result, etc. It
|
||
is normally run as @code{root} like this:
|
||
|
||
@example
|
||
# guix-daemon --build-users-group=guix-builder
|
||
@end example
|
||
|
||
@noindent
|
||
For details on how to set it up, @ref{Setting Up the Daemon}.
|
||
|
||
@cindex chroot
|
||
@cindex container, build environment
|
||
@cindex build environment
|
||
@cindex reproducible builds
|
||
By default, @command{guix-daemon} launches build processes under
|
||
different UIDs, taken from the build group specified with
|
||
@code{--build-users-group}. In addition, each build process is run in a
|
||
chroot environment that only contains the subset of the store that the
|
||
build process depends on, as specified by its derivation
|
||
(@pxref{Programming Interface, derivation}), plus a set of specific
|
||
system directories. By default, the latter contains @file{/dev} and
|
||
@file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
|
||
@dfn{container}: in addition to having its own file system tree, it has
|
||
a separate mount name space, its own PID name space, network name space,
|
||
etc. This helps achieve reproducible builds (@pxref{Features}).
|
||
|
||
The following command-line options are supported:
|
||
|
||
@table @code
|
||
@item --build-users-group=@var{group}
|
||
Take users from @var{group} to run build processes (@pxref{Setting Up
|
||
the Daemon, build users}).
|
||
|
||
@item --no-substitutes
|
||
@cindex substitutes
|
||
Do not use substitutes for build products. That is, always build things
|
||
locally instead of allowing downloads of pre-built binaries
|
||
(@pxref{Substitutes}).
|
||
|
||
By default substitutes are used, unless the client---such as the
|
||
@command{guix package} command---is explicitly invoked with
|
||
@code{--no-substitutes}.
|
||
|
||
When the daemon runs with @code{--no-substitutes}, clients can still
|
||
explicitly enable substitution @i{via} the @code{set-build-options}
|
||
remote procedure call (@pxref{The Store}).
|
||
|
||
@cindex build hook
|
||
@item --no-build-hook
|
||
Do not use the @dfn{build hook}.
|
||
|
||
The build hook is a helper program that the daemon can start and to
|
||
which it submits build requests. This mechanism is used to offload
|
||
builds to other machines (@pxref{Daemon Offload Setup}).
|
||
|
||
@item --cache-failures
|
||
Cache build failures. By default, only successful builds are cached.
|
||
|
||
@item --cores=@var{n}
|
||
@itemx -c @var{n}
|
||
Use @var{n} CPU cores to build each derivation; @code{0} means as many
|
||
as available.
|
||
|
||
The default value is @code{1}, but it may be overridden by clients, such
|
||
as the @code{--cores} option of @command{guix build} (@pxref{Invoking
|
||
guix build}).
|
||
|
||
The effect is to define the @code{NIX_BUILD_CORES} environment variable
|
||
in the build process, which can then use it to exploit internal
|
||
parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
|
||
|
||
@item --max-jobs=@var{n}
|
||
@itemx -M @var{n}
|
||
Allow at most @var{n} build jobs in parallel. The default value is
|
||
@code{1}.
|
||
|
||
@item --debug
|
||
Produce debugging output.
|
||
|
||
This is useful to debug daemon start-up issues, but then it may be
|
||
overridden by clients, for example the @code{--verbosity} option of
|
||
@command{guix build} (@pxref{Invoking guix build}).
|
||
|
||
@item --chroot-directory=@var{dir}
|
||
Add @var{dir} to the build chroot.
|
||
|
||
Doing this may change the result of build processes---for instance if
|
||
they use optional dependencies found in @var{dir} when it is available,
|
||
and not otherwise. For that reason, it is not recommended to do so.
|
||
Instead, make sure that each derivation declares all the inputs that it
|
||
needs.
|
||
|
||
@item --disable-chroot
|
||
Disable chroot builds.
|
||
|
||
Using this option is not recommended since, again, it would allow build
|
||
processes to gain access to undeclared dependencies.
|
||
|
||
@item --disable-log-compression
|
||
Disable compression of the build logs.
|
||
|
||
Unless @code{--lose-logs} is used, all the build logs are kept in the
|
||
@var{localstatedir}. To save space, the daemon automatically compresses
|
||
them with bzip2 by default. This option disables that.
|
||
|
||
@item --disable-deduplication
|
||
@cindex deduplication
|
||
Disable automatic file ``deduplication'' in the store.
|
||
|
||
By default, files added to the store are automatically ``deduplicated'':
|
||
if a newly added file is identical to another one found in the store,
|
||
the daemon makes the new file a hard link to the other file. This can
|
||
noticeably reduce disk usage, at the expense of slightly increasde
|
||
input/output load at the end of a build process. This option disables
|
||
this optimization.
|
||
|
||
@item --gc-keep-outputs[=yes|no]
|
||
Tell whether the garbage collector (GC) must keep outputs of live
|
||
derivations.
|
||
|
||
When set to ``yes'', the GC will keep the outputs of any live derivation
|
||
available in the store---the @code{.drv} files. The default is ``no'',
|
||
meaning that derivation outputs are kept only if they are GC roots.
|
||
|
||
@item --gc-keep-derivations[=yes|no]
|
||
Tell whether the garbage collector (GC) must keep derivations
|
||
corresponding to live outputs.
|
||
|
||
When set to ``yes'', as is the case by default, the GC keeps
|
||
derivations---i.e., @code{.drv} files---as long as at least one of their
|
||
outputs is live. This allows users to keep track of the origins of
|
||
items in their store. Setting it to ``no'' saves a bit of disk space.
|
||
|
||
Note that when both @code{--gc-keep-derivations} and
|
||
@code{--gc-keep-outputs} are used, the effect is to keep all the build
|
||
prerequisites (the sources, compiler, libraries, and other build-time
|
||
tools) of live objects in the store, regardless of whether these
|
||
prerequisites are live. This is convenient for developers since it
|
||
saves rebuilds or downloads.
|
||
|
||
@item --impersonate-linux-2.6
|
||
On Linux-based systems, impersonate Linux 2.6. This means that the
|
||
kernel's @code{uname} system call will report 2.6 as the release number.
|
||
|
||
This might be helpful to build programs that (usually wrongfully) depend
|
||
on the kernel version number.
|
||
|
||
@item --lose-logs
|
||
Do not keep build logs. By default they are kept under
|
||
@code{@var{localstatedir}/guix/log}.
|
||
|
||
@item --system=@var{system}
|
||
Assume @var{system} as the current system type. By default it is the
|
||
architecture/kernel pair found at configure time, such as
|
||
@code{x86_64-linux}.
|
||
|
||
@item --listen=@var{socket}
|
||
Listen for connections on @var{socket}, the file name of a Unix-domain
|
||
socket. The default socket is
|
||
@file{@var{localstatedir}/daemon-socket/socket}. This option is only
|
||
useful in exceptional circumstances, such as if you need to run several
|
||
daemons on the same machine.
|
||
@end table
|
||
|
||
|
||
@c *********************************************************************
|
||
@node Package Management
|
||
@chapter Package Management
|
||
|
||
The purpose of GNU Guix is to allow users to easily install, upgrade, and
|
||
remove software packages, without having to know about their build
|
||
procedure or dependencies. Guix also goes beyond this obvious set of
|
||
features.
|
||
|
||
This chapter describes the main features of Guix, as well as the package
|
||
management tools it provides.
|
||
|
||
@menu
|
||
* Features:: How Guix will make your life brighter.
|
||
* Invoking guix package:: Package installation, removal, etc.
|
||
* Substitutes:: Downloading pre-built binaries.
|
||
* Packages with Multiple Outputs:: Single source package, multiple outputs.
|
||
* Invoking guix gc:: Running the garbage collector.
|
||
* Invoking guix pull:: Fetching the latest Guix and distribution.
|
||
* Invoking guix archive:: Exporting and importing store files.
|
||
@end menu
|
||
|
||
@node Features
|
||
@section Features
|
||
|
||
When using Guix, each package ends up in the @dfn{package store}, in its
|
||
own directory---something that resembles
|
||
@file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
|
||
|
||
Instead of referring to these directories, users have their own
|
||
@dfn{profile}, which points to the packages that they actually want to
|
||
use. These profiles are stored within each user's home directory, at
|
||
@code{$HOME/.guix-profile}.
|
||
|
||
For example, @code{alice} installs GCC 4.7.2. As a result,
|
||
@file{/home/alice/.guix-profile/bin/gcc} points to
|
||
@file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
|
||
@code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
|
||
simply continues to point to
|
||
@file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
|
||
coexist on the same system without any interference.
|
||
|
||
The @command{guix package} command is the central tool to manage
|
||
packages (@pxref{Invoking guix package}). It operates on those per-user
|
||
profiles, and can be used @emph{with normal user privileges}.
|
||
|
||
The command provides the obvious install, remove, and upgrade
|
||
operations. Each invocation is actually a @emph{transaction}: either
|
||
the specified operation succeeds, or nothing happens. Thus, if the
|
||
@command{guix package} process is terminated during the transaction,
|
||
or if a power outage occurs during the transaction, then the user's
|
||
profile remains in its previous state, and remains usable.
|
||
|
||
In addition, any package transaction may be @emph{rolled back}. So, if,
|
||
for example, an upgrade installs a new version of a package that turns
|
||
out to have a serious bug, users may roll back to the previous instance
|
||
of their profile, which was known to work well. Similarly, the global
|
||
system configuration is subject to transactional upgrades and roll-back
|
||
(@pxref{Using the Configuration System}).
|
||
|
||
All those packages in the package store may be @emph{garbage-collected}.
|
||
Guix can determine which packages are still referenced by the user
|
||
profiles, and remove those that are provably no longer referenced
|
||
(@pxref{Invoking guix gc}). Users may also explicitly remove old
|
||
generations of their profile so that the packages they refer to can be
|
||
collected.
|
||
|
||
@cindex reproducibility
|
||
@cindex reproducible builds
|
||
Finally, Guix takes a @dfn{purely functional} approach to package
|
||
management, as described in the introduction (@pxref{Introduction}).
|
||
Each @file{/gnu/store} package directory name contains a hash of all the
|
||
inputs that were used to build that package---compiler, libraries, build
|
||
scripts, etc. This direct correspondence allows users to make sure a
|
||
given package installation matches the current state of their
|
||
distribution. It also helps maximize @dfn{build reproducibility}:
|
||
thanks to the isolated build environments that are used, a given build
|
||
is likely to yield bit-identical files when performed on different
|
||
machines (@pxref{Invoking guix-daemon, container}).
|
||
|
||
@cindex substitutes
|
||
This foundation allows Guix to support @dfn{transparent binary/source
|
||
deployment}. When a pre-built binary for a @file{/gnu/store} item is
|
||
available from an external source---a @dfn{substitute}, Guix just
|
||
downloads it and unpacks it;
|
||
otherwise, it builds the package from source, locally
|
||
(@pxref{Substitutes}).
|
||
|
||
@node Invoking guix package
|
||
@section Invoking @command{guix package}
|
||
|
||
The @command{guix package} command is the tool that allows users to
|
||
install, upgrade, and remove packages, as well as rolling back to
|
||
previous configurations. It operates only on the user's own profile,
|
||
and works with normal user privileges (@pxref{Features}). Its syntax
|
||
is:
|
||
|
||
@example
|
||
guix package @var{options}
|
||
@end example
|
||
|
||
Primarily, @var{options} specifies the operations to be performed during
|
||
the transaction. Upon completion, a new profile is created, but
|
||
previous generations of the profile remain available, should the user
|
||
want to roll back.
|
||
|
||
For example, to remove @code{lua} and install @code{guile} and
|
||
@code{guile-cairo} in a single transaction:
|
||
|
||
@example
|
||
guix package -r lua -i guile guile-cairo
|
||
@end example
|
||
|
||
For each user, a symlink to the user's default profile is automatically
|
||
created in @file{$HOME/.guix-profile}. This symlink always points to the
|
||
current generation of the user's default profile. Thus, users can add
|
||
@file{$HOME/.guix-profile/bin} to their @code{PATH} environment
|
||
variable, and so on.
|
||
|
||
In a multi-user setup, user profiles must be stored in a place
|
||
registered as a @dfn{garbage-collector root}, which
|
||
@file{$HOME/.guix-profile} points to (@pxref{Invoking guix gc}). That
|
||
directory is normally
|
||
@code{@var{localstatedir}/profiles/per-user/@var{user}}, where
|
||
@var{localstatedir} is the value passed to @code{configure} as
|
||
@code{--localstatedir}, and @var{user} is the user name. It must be
|
||
created by @code{root}, with @var{user} as the owner. When it does not
|
||
exist, or is not owned by @var{user}, @command{guix package} emits an
|
||
error about it.
|
||
|
||
The @var{options} can be among the following:
|
||
|
||
@table @code
|
||
|
||
@item --install=@var{package} @dots{}
|
||
@itemx -i @var{package} @dots{}
|
||
Install the specified @var{package}s.
|
||
|
||
Each @var{package} may specify either a simple package name, such as
|
||
@code{guile}, or a package name followed by a hyphen and version number,
|
||
such as @code{guile-1.8.8}. If no version number is specified, the
|
||
newest available version will be selected. In addition, @var{package}
|
||
may contain a colon, followed by the name of one of the outputs of the
|
||
package, as in @code{gcc:doc} or @code{binutils-2.22:lib}
|
||
(@pxref{Packages with Multiple Outputs}). Packages with a corresponding
|
||
name (and optionally version) are searched for among the GNU
|
||
distribution modules (@pxref{Package Modules}).
|
||
|
||
@cindex propagated inputs
|
||
Sometimes packages have @dfn{propagated inputs}: these are dependencies
|
||
that automatically get installed along with the required package.
|
||
|
||
An example is the GNU MPC library: its C header files refer to those of
|
||
the GNU MPFR library, which in turn refer to those of the GMP library.
|
||
Thus, when installing MPC, the MPFR and GMP libraries also get installed
|
||
in the profile; removing MPC also removes MPFR and GMP---unless they had
|
||
also been explicitly installed independently.
|
||
|
||
Besides, packages sometimes rely on the definition of environment
|
||
variables for their search paths (see explanation of
|
||
@code{--search-paths} below). Any missing or possibly incorrect
|
||
environment variable definitions are reported here.
|
||
|
||
@c XXX: keep me up-to-date
|
||
Finally, when installing a GNU package, the tool reports the
|
||
availability of a newer upstream version. In the future, it may provide
|
||
the option of installing directly from the upstream version, even if
|
||
that version is not yet in the distribution.
|
||
|
||
@item --install-from-expression=@var{exp}
|
||
@itemx -e @var{exp}
|
||
Install the package @var{exp} evaluates to.
|
||
|
||
@var{exp} must be a Scheme expression that evaluates to a
|
||
@code{<package>} object. This option is notably useful to disambiguate
|
||
between same-named variants of a package, with expressions such as
|
||
@code{(@@ (gnu packages base) guile-final)}.
|
||
|
||
Note that this option installs the first output of the specified
|
||
package, which may be insufficient when needing a specific output of a
|
||
multiple-output package.
|
||
|
||
@item --remove=@var{package} @dots{}
|
||
@itemx -r @var{package} @dots{}
|
||
Remove the specified @var{package}s.
|
||
|
||
As for @code{--install}, each @var{package} may specify a version number
|
||
and/or output name in addition to the package name. For instance,
|
||
@code{-r glibc:debug} would remove the @code{debug} output of
|
||
@code{glibc}.
|
||
|
||
@item --upgrade[=@var{regexp} @dots{}]
|
||
@itemx -u [@var{regexp} @dots{}]
|
||
Upgrade all the installed packages. If one or more @var{regexp}s are
|
||
specified, upgrade only installed packages whose name matches a
|
||
@var{regexp}.
|
||
|
||
Note that this upgrades package to the latest version of packages found
|
||
in the distribution currently installed. To update your distribution,
|
||
you should regularly run @command{guix pull} (@pxref{Invoking guix
|
||
pull}).
|
||
|
||
@item --roll-back
|
||
Roll back to the previous @dfn{generation} of the profile---i.e., undo
|
||
the last transaction.
|
||
|
||
When combined with options such as @code{--install}, roll back occurs
|
||
before any other actions.
|
||
|
||
When rolling back from the first generation that actually contains
|
||
installed packages, the profile is made to point to the @dfn{zeroth
|
||
generation}, which contains no files apart from its own meta-data.
|
||
|
||
Installing, removing, or upgrading packages from a generation that has
|
||
been rolled back to overwrites previous future generations. Thus, the
|
||
history of a profile's generations is always linear.
|
||
|
||
@item --search-paths
|
||
@cindex search paths
|
||
Report environment variable definitions, in Bash syntax, that may be
|
||
needed in order to use the set of installed packages. These environment
|
||
variables are used to specify @dfn{search paths} for files used by some
|
||
of the installed packages.
|
||
|
||
For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
|
||
environment variables to be defined so it can look for headers and
|
||
libraries in the user's profile (@pxref{Environment Variables,,, gcc,
|
||
Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
|
||
library are installed in the profile, then @code{--search-paths} will
|
||
suggest setting these variables to @code{@var{profile}/include} and
|
||
@code{@var{profile}/lib}, respectively.
|
||
|
||
@item --profile=@var{profile}
|
||
@itemx -p @var{profile}
|
||
Use @var{profile} instead of the user's default profile.
|
||
|
||
@item --verbose
|
||
Produce verbose output. In particular, emit the environment's build log
|
||
on the standard error port.
|
||
|
||
@item --bootstrap
|
||
Use the bootstrap Guile to build the profile. This option is only
|
||
useful to distribution developers.
|
||
|
||
@end table
|
||
|
||
In addition to these actions @command{guix package} supports the
|
||
following options to query the current state of a profile, or the
|
||
availability of packages:
|
||
|
||
@table @option
|
||
|
||
@item --search=@var{regexp}
|
||
@itemx -s @var{regexp}
|
||
List the available packages whose synopsis or description matches
|
||
@var{regexp}. Print all the meta-data of matching packages in
|
||
@code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
|
||
GNU recutils manual}).
|
||
|
||
This allows specific fields to be extracted using the @command{recsel}
|
||
command, for instance:
|
||
|
||
@example
|
||
$ guix package -s malloc | recsel -p name,version
|
||
name: glibc
|
||
version: 2.17
|
||
|
||
name: libgc
|
||
version: 7.2alpha6
|
||
@end example
|
||
|
||
Similarly, to show the name of all the packages available under the
|
||
terms of the GNU@tie{}LGPL version 3:
|
||
|
||
@example
|
||
$ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
|
||
name: elfutils
|
||
|
||
name: gmp
|
||
@dots{}
|
||
@end example
|
||
|
||
@item --show=@var{package}
|
||
Show details about @var{package}, taken from the list of available packages, in
|
||
@code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
|
||
recutils manual}).
|
||
|
||
@example
|
||
$ guix package --show=python | recsel -p name,version
|
||
name: python
|
||
version: 2.7.6
|
||
|
||
name: python
|
||
version: 3.3.5
|
||
@end example
|
||
|
||
You may also specify the full name of a package to only get details about a
|
||
specific version of it:
|
||
@example
|
||
$ guix package --show=python-3.3.5 | recsel -p name,version
|
||
name: python
|
||
version: 3.3.5
|
||
@end example
|
||
|
||
|
||
|
||
@item --list-installed[=@var{regexp}]
|
||
@itemx -I [@var{regexp}]
|
||
List the currently installed packages in the specified profile, with the
|
||
most recently installed packages shown last. When @var{regexp} is
|
||
specified, list only installed packages whose name matches @var{regexp}.
|
||
|
||
For each installed package, print the following items, separated by
|
||
tabs: the package name, its version string, the part of the package that
|
||
is installed (for instance, @code{out} for the default output,
|
||
@code{include} for its headers, etc.), and the path of this package in
|
||
the store.
|
||
|
||
@item --list-available[=@var{regexp}]
|
||
@itemx -A [@var{regexp}]
|
||
List packages currently available in the software distribution
|
||
(@pxref{GNU Distribution}). When @var{regexp} is specified, list only
|
||
installed packages whose name matches @var{regexp}.
|
||
|
||
For each package, print the following items separated by tabs: its name,
|
||
its version string, the parts of the package (@pxref{Packages with
|
||
Multiple Outputs}), and the source location of its definition.
|
||
|
||
@item --list-generations[=@var{pattern}]
|
||
@itemx -l [@var{pattern}]
|
||
Return a list of generations along with their creation dates; for each
|
||
generation, show the installed packages, with the most recently
|
||
installed packages shown last. Note that the zeroth generation is never
|
||
shown.
|
||
|
||
For each installed package, print the following items, separated by
|
||
tabs: the name of a package, its version string, the part of the package
|
||
that is installed (@pxref{Packages with Multiple Outputs}), and the
|
||
location of this package in the store.
|
||
|
||
When @var{pattern} is used, the command returns only matching
|
||
generations. Valid patterns include:
|
||
|
||
@itemize
|
||
@item @emph{Integers and comma-separated integers}. Both patterns denote
|
||
generation numbers. For instance, @code{--list-generations=1} returns
|
||
the first one.
|
||
|
||
And @code{--list-generations=1,8,2} outputs three generations in the
|
||
specified order. Neither spaces nor trailing commas are allowed.
|
||
|
||
@item @emph{Ranges}. @code{--list-generations=2..9} prints the
|
||
specified generations and everything in between. Note that the start of
|
||
a range must be lesser than its end.
|
||
|
||
It is also possible to omit the endpoint. For example,
|
||
@code{--list-generations=2..}, returns all generations starting from the
|
||
second one.
|
||
|
||
@item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
|
||
or months by passing an integer along with the first letter of the
|
||
duration. For example, @code{--list-generations=20d} lists generations
|
||
that are up to 20 days old.
|
||
@end itemize
|
||
|
||
@item --delete-generations[=@var{pattern}]
|
||
@itemx -d [@var{pattern}]
|
||
When @var{pattern} is omitted, delete all generations except the current
|
||
one.
|
||
|
||
This command accepts the same patterns as @option{--list-generations}.
|
||
When @var{pattern} is specified, delete the matching generations. When
|
||
@var{pattern} specifies a duration, generations @emph{older} than the
|
||
specified duration match. For instance, @code{--delete-generations=1m}
|
||
deletes generations that are more than one month old.
|
||
|
||
If the current generation matches, it is deleted atomically---i.e., by
|
||
switching to the previous available generation. Note that the zeroth
|
||
generation is never deleted.
|
||
|
||
Note that deleting generations prevents roll-back to them.
|
||
Consequently, this command must be used with care.
|
||
|
||
@end table
|
||
|
||
Finally, since @command{guix package} may actually start build
|
||
processes, it supports all the common build options that @command{guix
|
||
build} supports (@pxref{Invoking guix build, common build options}).
|
||
|
||
@node Substitutes
|
||
@section Substitutes
|
||
|
||
@cindex substitutes
|
||
@cindex pre-built binaries
|
||
Guix supports transparent source/binary deployment, which means that it
|
||
can either build things locally, or download pre-built items from a
|
||
server. We call these pre-built items @dfn{substitutes}---they are
|
||
substitutes for local build results. In many cases, downloading a
|
||
substitute is much faster than building things locally.
|
||
|
||
Substitutes can be anything resulting from a derivation build
|
||
(@pxref{Derivations}). Of course, in the common case, they are
|
||
pre-built package binaries, but source tarballs, for instance, which
|
||
also result from derivation builds, can be available as substitutes.
|
||
|
||
The @code{hydra.gnu.org} server is a front-end to a build farm that
|
||
builds packages from the GNU distribution continuously for some
|
||
architectures, and makes them available as substitutes.
|
||
|
||
@cindex security
|
||
@cindex digital signatures
|
||
To allow Guix to download substitutes from @code{hydra.gnu.org}, you
|
||
must add its public key to the access control list (ACL) of archive
|
||
imports, using the @command{guix archive} command (@pxref{Invoking guix
|
||
archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
|
||
be compromised and to serve genuine substitutes.
|
||
|
||
This public key is installed along with Guix, in
|
||
@code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
|
||
the installation prefix of Guix. If you installed Guix from source,
|
||
make sure you checked the GPG signature of
|
||
@file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
|
||
Then, you can run something like this:
|
||
|
||
@example
|
||
# guix archive --authorize < hydra.gnu.org.pub
|
||
@end example
|
||
|
||
Once this is in place, the output of a command like @code{guix build}
|
||
should change from something like:
|
||
|
||
@example
|
||
$ guix build emacs --dry-run
|
||
The following derivations would be built:
|
||
/gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
|
||
/gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
|
||
/gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
|
||
/gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
|
||
@dots{}
|
||
@end example
|
||
|
||
@noindent
|
||
to something like:
|
||
|
||
@example
|
||
$ guix build emacs --dry-run
|
||
The following files would be downloaded:
|
||
/gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
|
||
/gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
|
||
/gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
|
||
/gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
|
||
@dots{}
|
||
@end example
|
||
|
||
@noindent
|
||
This indicates that substitutes from @code{hydra.gnu.org} are usable and
|
||
will be downloaded, when possible, for future builds.
|
||
|
||
Guix ignores substitutes that are not signed, or that are not signed by
|
||
one of the keys listed in the ACL. It also detects and raises an error
|
||
when attempting to use a substitute that has been tampered with.
|
||
|
||
The substitute mechanism can be disabled globally by running
|
||
@code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
|
||
guix-daemon}). It can also be disabled temporarily by passing the
|
||
@code{--no-substitutes} option to @command{guix package}, @command{guix
|
||
build}, and other command-line tools.
|
||
|
||
|
||
Today, each individual's control over their own computing is at the
|
||
mercy of institutions, corporations, and groups with enough power and
|
||
determination to subvert the computing infrastructure and exploit its
|
||
weaknesses. While using @code{hydra.gnu.org} substitutes can be
|
||
convenient, we encourage users to also build on their own, or even run
|
||
their own build farm, such that @code{hydra.gnu.org} is less of an
|
||
interesting target.
|
||
|
||
Guix has the foundations to maximize build reproducibility
|
||
(@pxref{Features}). In most cases, independent builds of a given
|
||
package or derivation should yield bit-identical results. Thus, through
|
||
a diverse set of independent package builds, we can strengthen the
|
||
integrity of our systems.
|
||
|
||
In the future, we want Guix to have support to publish and retrieve
|
||
binaries to/from other users, in a peer-to-peer fashion. If you would
|
||
like to discuss this project, join us on @email{guix-devel@@gnu.org}.
|
||
|
||
|
||
@node Packages with Multiple Outputs
|
||
@section Packages with Multiple Outputs
|
||
|
||
@cindex multiple-output packages
|
||
@cindex package outputs
|
||
|
||
Often, packages defined in Guix have a single @dfn{output}---i.e., the
|
||
source package leads exactly one directory in the store. When running
|
||
@command{guix package -i glibc}, one installs the default output of the
|
||
GNU libc package; the default output is called @code{out}, but its name
|
||
can be omitted as shown in this command. In this particular case, the
|
||
default output of @code{glibc} contains all the C header files, shared
|
||
libraries, static libraries, Info documentation, and other supporting
|
||
files.
|
||
|
||
Sometimes it is more appropriate to separate the various types of files
|
||
produced from a single source package into separate outputs. For
|
||
instance, the GLib C library (used by GTK+ and related packages)
|
||
installs more than 20 MiB of reference documentation as HTML pages.
|
||
To save space for users who do not need it, the documentation goes to a
|
||
separate output, called @code{doc}. To install the main GLib output,
|
||
which contains everything but the documentation, one would run:
|
||
|
||
@example
|
||
guix package -i glib
|
||
@end example
|
||
|
||
The command to install its documentation is:
|
||
|
||
@example
|
||
guix package -i glib:doc
|
||
@end example
|
||
|
||
Some packages install programs with different ``dependency footprints''.
|
||
For instance, the WordNet package install both command-line tools and
|
||
graphical user interfaces (GUIs). The former depend solely on the C
|
||
library, whereas the latter depend on Tcl/Tk and the underlying X
|
||
libraries. In this case, we leave the command-line tools in the default
|
||
output, whereas the GUIs are in a separate output. This allows users
|
||
who do not need the GUIs to save space.
|
||
|
||
There are several such multiple-output packages in the GNU distribution.
|
||
Other conventional output names include @code{lib} for libraries and
|
||
possibly header files, @code{bin} for stand-alone programs, and
|
||
@code{debug} for debugging information (@pxref{Installing Debugging
|
||
Files}). The outputs of a packages are listed in the third column of
|
||
the output of @command{guix package --list-available} (@pxref{Invoking
|
||
guix package}).
|
||
|
||
|
||
@node Invoking guix gc
|
||
@section Invoking @command{guix gc}
|
||
|
||
@cindex garbage collector
|
||
Packages that are installed but not used may be @dfn{garbage-collected}.
|
||
The @command{guix gc} command allows users to explicitly run the garbage
|
||
collector to reclaim space from the @file{/gnu/store} directory.
|
||
|
||
The garbage collector has a set of known @dfn{roots}: any file under
|
||
@file{/gnu/store} reachable from a root is considered @dfn{live} and
|
||
cannot be deleted; any other file is considered @dfn{dead} and may be
|
||
deleted. The set of garbage collector roots includes default user
|
||
profiles, and may be augmented with @command{guix build --root}, for
|
||
example (@pxref{Invoking guix build}).
|
||
|
||
Prior to running @code{guix gc --collect-garbage} to make space, it is
|
||
often useful to remove old generations from user profiles; that way, old
|
||
package builds referenced by those generations can be reclaimed. This
|
||
is achieved by running @code{guix package --delete-generations}
|
||
(@pxref{Invoking guix package}).
|
||
|
||
The @command{guix gc} command has three modes of operation: it can be
|
||
used to garbage-collect any dead files (the default), to delete specific
|
||
files (the @code{--delete} option), or to print garbage-collector
|
||
information. The available options are listed below:
|
||
|
||
@table @code
|
||
@item --collect-garbage[=@var{min}]
|
||
@itemx -C [@var{min}]
|
||
Collect garbage---i.e., unreachable @file{/gnu/store} files and
|
||
sub-directories. This is the default operation when no option is
|
||
specified.
|
||
|
||
When @var{min} is given, stop once @var{min} bytes have been collected.
|
||
@var{min} may be a number of bytes, or it may include a unit as a
|
||
suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes.
|
||
|
||
When @var{min} is omitted, collect all the garbage.
|
||
|
||
@item --delete
|
||
@itemx -d
|
||
Attempt to delete all the store files and directories specified as
|
||
arguments. This fails if some of the files are not in the store, or if
|
||
they are still live.
|
||
|
||
@item --list-dead
|
||
Show the list of dead files and directories still present in the
|
||
store---i.e., files and directories no longer reachable from any root.
|
||
|
||
@item --list-live
|
||
Show the list of live store files and directories.
|
||
|
||
@end table
|
||
|
||
In addition, the references among existing store files can be queried:
|
||
|
||
@table @code
|
||
|
||
@item --references
|
||
@itemx --referrers
|
||
List the references (respectively, the referrers) of store files given
|
||
as arguments.
|
||
|
||
@item --requisites
|
||
@itemx -R
|
||
List the requisites of the store files passed as arguments. Requisites
|
||
include the store files themselves, their references, and the references
|
||
of these, recursively. In other words, the returned list is the
|
||
@dfn{transitive closure} of the store files.
|
||
|
||
@end table
|
||
|
||
|
||
@node Invoking guix pull
|
||
@section Invoking @command{guix pull}
|
||
|
||
Packages are installed or upgraded to the latest version available in
|
||
the distribution currently available on your local machine. To update
|
||
that distribution, along with the Guix tools, you must run @command{guix
|
||
pull}: the command downloads the latest Guix source code and package
|
||
descriptions, and deploys it.
|
||
|
||
On completion, @command{guix package} will use packages and package
|
||
versions from this just-retrieved copy of Guix. Not only that, but all
|
||
the Guix commands and Scheme modules will also be taken from that latest
|
||
version. New @command{guix} sub-commands added by the update also
|
||
become available.
|
||
|
||
The @command{guix pull} command is usually invoked with no arguments,
|
||
but it supports the following options:
|
||
|
||
@table @code
|
||
@item --verbose
|
||
Produce verbose output, writing build logs to the standard error output.
|
||
|
||
@item --url=@var{url}
|
||
Download the source tarball of Guix from @var{url}.
|
||
|
||
By default, the tarball is taken from its canonical address at
|
||
@code{gnu.org}, for the stable branch of Guix.
|
||
|
||
@item --bootstrap
|
||
Use the bootstrap Guile to build the latest Guix. This option is only
|
||
useful to Guix developers.
|
||
@end table
|
||
|
||
|
||
@node Invoking guix archive
|
||
@section Invoking @command{guix archive}
|
||
|
||
The @command{guix archive} command allows users to @dfn{export} files
|
||
from the store into a single archive, and to later @dfn{import} them.
|
||
In particular, it allows store files to be transferred from one machine
|
||
to another machine's store. For example, to transfer the @code{emacs}
|
||
package to a machine connected over SSH, one would run:
|
||
|
||
@example
|
||
guix archive --export emacs | ssh the-machine guix archive --import
|
||
@end example
|
||
|
||
@noindent
|
||
However, note that, in this example, all of @code{emacs} and its
|
||
dependencies are transferred, regardless of what is already available in
|
||
the target machine's store. The @code{--missing} option can help figure
|
||
out which items are missing from the target's store.
|
||
|
||
Archives are stored in the ``Nix archive'' or ``Nar'' format, which is
|
||
comparable in spirit to `tar', but with a few noteworthy differences
|
||
that make it more appropriate for our purposes. First, rather than
|
||
recording all Unix meta-data for each file, the Nar format only mentions
|
||
the file type (regular, directory, or symbolic link); Unix permissions
|
||
and owner/group are dismissed. Second, the order in which directory
|
||
entries are stored always follows the order of file names according to
|
||
the C locale collation order. This makes archive production fully
|
||
deterministic.
|
||
|
||
When exporting, the daemon digitally signs the contents of the archive,
|
||
and that digital signature is appended. When importing, the daemon
|
||
verifies the signature and rejects the import in case of an invalid
|
||
signature or if the signing key is not authorized.
|
||
@c FIXME: Add xref to daemon doc about signatures.
|
||
|
||
The main options are:
|
||
|
||
@table @code
|
||
@item --export
|
||
Export the specified store files or packages (see below.) Write the
|
||
resulting archive to the standard output.
|
||
|
||
@item --import
|
||
Read an archive from the standard input, and import the files listed
|
||
therein into the store. Abort if the archive has an invalid digital
|
||
signature, or if it is signed by a public key not among the authorized
|
||
keys (see @code{--authorize} below.)
|
||
|
||
@item --missing
|
||
Read a list of store file names from the standard input, one per line,
|
||
and write on the standard output the subset of these files missing from
|
||
the store.
|
||
|
||
@item --generate-key[=@var{parameters}]
|
||
@cindex signing, archives
|
||
Generate a new key pair for the daemons. This is a prerequisite before
|
||
archives can be exported with @code{--export}. Note that this operation
|
||
usually takes time, because it needs to gather enough entropy to
|
||
generate the key pair.
|
||
|
||
The generated key pair is typically stored under @file{/etc/guix}, in
|
||
@file{signing-key.pub} (public key) and @file{signing-key.sec} (private
|
||
key, which must be kept secret.) When @var{parameters} is omitted, it
|
||
is a 4096-bit RSA key. Alternately, @var{parameters} can specify
|
||
@code{genkey} parameters suitable for Libgcrypt (@pxref{General
|
||
public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
|
||
Libgcrypt Reference Manual}).
|
||
|
||
@item --authorize
|
||
@cindex authorizing, archives
|
||
Authorize imports signed by the public key passed on standard input.
|
||
The public key must be in ``s-expression advanced format''---i.e., the
|
||
same format as the @file{signing-key.pub} file.
|
||
|
||
The list of authorized keys is kept in the human-editable file
|
||
@file{/etc/guix/acl}. The file contains
|
||
@url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
|
||
s-expressions''} and is structured as an access-control list in the
|
||
@url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
|
||
(SPKI)}.
|
||
@end table
|
||
|
||
To export store files as an archive to the standard output, run:
|
||
|
||
@example
|
||
guix archive --export @var{options} @var{specifications}...
|
||
@end example
|
||
|
||
@var{specifications} may be either store file names or package
|
||
specifications, as for @command{guix package} (@pxref{Invoking guix
|
||
package}). For instance, the following command creates an archive
|
||
containing the @code{gui} output of the @code{git} package and the main
|
||
output of @code{emacs}:
|
||
|
||
@example
|
||
guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
|
||
@end example
|
||
|
||
If the specified packages are not built yet, @command{guix archive}
|
||
automatically builds them. The build process may be controlled with the
|
||
same options that can be passed to the @command{guix build} command
|
||
(@pxref{Invoking guix build, common build options}).
|
||
|
||
|
||
@c *********************************************************************
|
||
@node Programming Interface
|
||
@chapter Programming Interface
|
||
|
||
GNU Guix provides several Scheme programming interfaces (APIs) to
|
||
define, build, and query packages. The first interface allows users to
|
||
write high-level package definitions. These definitions refer to
|
||
familiar packaging concepts, such as the name and version of a package,
|
||
its build system, and its dependencies. These definitions can then be
|
||
turned into concrete build actions.
|
||
|
||
Build actions are performed by the Guix daemon, on behalf of users. In a
|
||
standard setup, the daemon has write access to the store---the
|
||
@file{/gnu/store} directory---whereas users do not. The recommended
|
||
setup also has the daemon perform builds in chroots, under a specific
|
||
build users, to minimize interference with the rest of the system.
|
||
|
||
@cindex derivation
|
||
Lower-level APIs are available to interact with the daemon and the
|
||
store. To instruct the daemon to perform a build action, users actually
|
||
provide it with a @dfn{derivation}. A derivation is a low-level
|
||
representation of the build actions to be taken, and the environment in
|
||
which they should occur---derivations are to package definitions what
|
||
assembly is to C programs. The term ``derivation'' comes from the fact
|
||
that build results @emph{derive} from them.
|
||
|
||
This chapter describes all these APIs in turn, starting from high-level
|
||
package definitions.
|
||
|
||
@menu
|
||
* Defining Packages:: Defining new packages.
|
||
* Build Systems:: Specifying how packages are built.
|
||
* The Store:: Manipulating the package store.
|
||
* Derivations:: Low-level interface to package derivations.
|
||
* The Store Monad:: Purely functional interface to the store.
|
||
* G-Expressions:: Manipulating build expressions.
|
||
@end menu
|
||
|
||
@node Defining Packages
|
||
@section Defining Packages
|
||
|
||
The high-level interface to package definitions is implemented in the
|
||
@code{(guix packages)} and @code{(guix build-system)} modules. As an
|
||
example, the package definition, or @dfn{recipe}, for the GNU Hello
|
||
package looks like this:
|
||
|
||
@example
|
||
(define-module (gnu packages hello)
|
||
#:use-module (guix packages)
|
||
#:use-module (guix download)
|
||
#:use-module (guix build-system gnu)
|
||
#:use-module (guix licenses))
|
||
|
||
(define hello
|
||
(package
|
||
(name "hello")
|
||
(version "2.8")
|
||
(source (origin
|
||
(method url-fetch)
|
||
(uri (string-append "mirror://gnu/hello/hello-" version
|
||
".tar.gz"))
|
||
(sha256
|
||
(base32 "0wqd8sjmxfskrflaxywc7gqw7sfawrfvdxd9skxawzfgyy0pzdz6"))))
|
||
(build-system gnu-build-system)
|
||
(arguments `(#:configure-flags '("--enable-silent-rules")))
|
||
(inputs `(("gawk" ,gawk)))
|
||
(synopsis "Hello, GNU world: An example GNU package")
|
||
(description "Guess what GNU Hello prints!")
|
||
(home-page "http://www.gnu.org/software/hello/")
|
||
(license gpl3+)))
|
||
@end example
|
||
|
||
@noindent
|
||
Without being a Scheme expert, the reader may have guessed the meaning
|
||
of the various fields here. This expression binds variable @code{hello}
|
||
to a @code{<package>} object, which is essentially a record
|
||
(@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
|
||
This package object can be inspected using procedures found in the
|
||
@code{(guix packages)} module; for instance, @code{(package-name hello)}
|
||
returns---surprise!---@code{"hello"}.
|
||
|
||
In the example above, @var{hello} is defined into a module of its own,
|
||
@code{(gnu packages hello)}. Technically, this is not strictly
|
||
necessary, but it is convenient to do so: all the packages defined in
|
||
modules under @code{(gnu packages @dots{})} are automatically known to
|
||
the command-line tools (@pxref{Package Modules}).
|
||
|
||
There are a few points worth noting in the above package definition:
|
||
|
||
@itemize
|
||
@item
|
||
The @code{source} field of the package is an @code{<origin>} object.
|
||
Here, the @code{url-fetch} method from @code{(guix download)} is used,
|
||
meaning that the source is a file to be downloaded over FTP or HTTP.
|
||
|
||
The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
|
||
the GNU mirrors defined in @code{(guix download)}.
|
||
|
||
The @code{sha256} field specifies the expected SHA256 hash of the file
|
||
being downloaded. It is mandatory, and allows Guix to check the
|
||
integrity of the file. The @code{(base32 @dots{})} form introduces the
|
||
base32 representation of the hash. You can obtain this information with
|
||
@code{guix download} (@pxref{Invoking guix download}) and @code{guix
|
||
hash} (@pxref{Invoking guix hash}).
|
||
|
||
@cindex patches
|
||
When needed, the @code{origin} form can also have a @code{patches} field
|
||
listing patches to be applied, and a @code{snippet} field giving a
|
||
Scheme expression to modify the source code.
|
||
|
||
@item
|
||
@cindex GNU Build System
|
||
The @code{build-system} field specifies the procedure to build the
|
||
package (@pxref{Build Systems}). Here, @var{gnu-build-system}
|
||
represents the familiar GNU Build System, where packages may be
|
||
configured, built, and installed with the usual @code{./configure &&
|
||
make && make check && make install} command sequence.
|
||
|
||
@item
|
||
The @code{arguments} field specifies options for the build system
|
||
(@pxref{Build Systems}). Here it is interpreted by
|
||
@var{gnu-build-system} as a request run @file{configure} with the
|
||
@code{--enable-silent-rules} flag.
|
||
|
||
@item
|
||
The @code{inputs} field specifies inputs to the build process---i.e.,
|
||
build-time or run-time dependencies of the package. Here, we define an
|
||
input called @code{"gawk"} whose value is that of the @var{gawk}
|
||
variable; @var{gawk} is itself bound to a @code{<package>} object.
|
||
|
||
Note that GCC, Coreutils, Bash, and other essential tools do not need to
|
||
be specified as inputs here. Instead, @var{gnu-build-system} takes care
|
||
of ensuring that they are present (@pxref{Build Systems}).
|
||
|
||
However, any other dependencies need to be specified in the
|
||
@code{inputs} field. Any dependency not specified here will simply be
|
||
unavailable to the build process, possibly leading to a build failure.
|
||
@end itemize
|
||
|
||
Once a package definition is in place@footnote{Simple package
|
||
definitions like the one above may be automatically converted from the
|
||
Nixpkgs distribution using the @command{guix import} command.}, the
|
||
package may actually be built using the @code{guix build} command-line
|
||
tool (@pxref{Invoking guix build}). @xref{Packaging Guidelines}, for
|
||
more information on how to test package definitions.
|
||
|
||
Eventually, updating the package definition to a new upstream version
|
||
can be partly automated by the @command{guix refresh} command
|
||
(@pxref{Invoking guix refresh}).
|
||
|
||
Behind the scenes, a derivation corresponding to the @code{<package>}
|
||
object is first computed by the @code{package-derivation} procedure.
|
||
That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
|
||
The build actions it prescribes may then be realized by using the
|
||
@code{build-derivations} procedure (@pxref{The Store}).
|
||
|
||
@deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
|
||
Return the @code{<derivation>} object of @var{package} for @var{system}
|
||
(@pxref{Derivations}).
|
||
|
||
@var{package} must be a valid @code{<package>} object, and @var{system}
|
||
must be a string denoting the target system type---e.g.,
|
||
@code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
|
||
must be a connection to the daemon, which operates on the store
|
||
(@pxref{The Store}).
|
||
@end deffn
|
||
|
||
@noindent
|
||
@cindex cross-compilation
|
||
Similarly, it is possible to compute a derivation that cross-builds a
|
||
package for some other system:
|
||
|
||
@deffn {Scheme Procedure} package-cross-derivation @var{store} @
|
||
@var{package} @var{target} [@var{system}]
|
||
Return the @code{<derivation>} object of @var{package} cross-built from
|
||
@var{system} to @var{target}.
|
||
|
||
@var{target} must be a valid GNU triplet denoting the target hardware
|
||
and operating system, such as @code{"mips64el-linux-gnu"}
|
||
(@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
|
||
Configure and Build System}).
|
||
@end deffn
|
||
|
||
|
||
@node Build Systems
|
||
@section Build Systems
|
||
|
||
@cindex build system
|
||
Each package definition specifies a @dfn{build system} and arguments for
|
||
that build system (@pxref{Defining Packages}). This @code{build-system}
|
||
field represents the build procedure of the package, as well implicit
|
||
dependencies of that build procedure.
|
||
|
||
Build systems are @code{<build-system>} objects. The interface to
|
||
create and manipulate them is provided by the @code{(guix build-system)}
|
||
module, and actual build systems are exported by specific modules.
|
||
|
||
Build systems accept an optional list of @dfn{arguments}. In package
|
||
definitions, these are passed @i{via} the @code{arguments} field
|
||
(@pxref{Defining Packages}). They are typically keyword arguments
|
||
(@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
|
||
Guile Reference Manual}). The value of these arguments is usually
|
||
evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
|
||
by the daemon (@pxref{Derivations}).
|
||
|
||
The main build system is @var{gnu-build-system}, which implements the
|
||
standard build procedure for GNU packages and many other packages. It
|
||
is provided by the @code{(guix build-system gnu)} module.
|
||
|
||
@defvr {Scheme Variable} gnu-build-system
|
||
@var{gnu-build-system} represents the GNU Build System, and variants
|
||
thereof (@pxref{Configuration, configuration and makefile conventions,,
|
||
standards, GNU Coding Standards}).
|
||
|
||
@cindex build phases
|
||
In a nutshell, packages using it configured, built, and installed with
|
||
the usual @code{./configure && make && make check && make install}
|
||
command sequence. In practice, a few additional steps are often needed.
|
||
All these steps are split up in separate @dfn{phases},
|
||
notably@footnote{Please see the @code{(guix build gnu-build-system)}
|
||
modules for more details about the build phases.}:
|
||
|
||
@table @code
|
||
@item unpack
|
||
Unpack the source tarball, and change the current directory to the
|
||
extracted source tree. If the source is actually a directory, copy it
|
||
to the build tree, and enter that directory.
|
||
|
||
@item patch-source-shebangs
|
||
Patch shebangs encountered in source files so they refer to the right
|
||
store file names. For instance, this changes @code{#!/bin/sh} to
|
||
@code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
|
||
|
||
@item configure
|
||
Run the @file{configure} script with a number of default options, such
|
||
as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
|
||
by the @code{#:configure-flags} argument.
|
||
|
||
@item build
|
||
Run @code{make} with the list of flags specified with
|
||
@code{#:make-flags}. If the @code{#:parallel-builds?} argument is true
|
||
(the default), build with @code{make -j}.
|
||
|
||
@item check
|
||
Run @code{make check}, or some other target specified with
|
||
@code{#:test-target}, unless @code{#:tests? #f} is passed. If the
|
||
@code{#:parallel-tests?} argument is true (the default), run @code{make
|
||
check -j}.
|
||
|
||
@item install
|
||
Run @code{make install} with the flags listed in @code{#:make-flags}.
|
||
|
||
@item patch-shebangs
|
||
Patch shebangs on the installed executable files.
|
||
|
||
@item strip
|
||
Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
|
||
is false), copying them to the @code{debug} output when available
|
||
(@pxref{Installing Debugging Files}).
|
||
@end table
|
||
|
||
@vindex %standard-phases
|
||
The build-side module @code{(guix build gnu-build-system)} defines
|
||
@var{%standard-phases} as the default list of build phases.
|
||
@var{%standard-phases} is a list of symbol/procedure pairs, where the
|
||
procedure implements the actual phase.
|
||
|
||
The list of phases used for a particular package can be changed with the
|
||
@code{#:phases} parameter. For instance, passing:
|
||
|
||
@example
|
||
#:phases (alist-delete 'configure %standard-phases)
|
||
@end example
|
||
|
||
means that all the phases described above will be used, except the
|
||
@code{configure} phase.
|
||
|
||
In addition, this build system ensures that the ``standard'' environment
|
||
for GNU packages is available. This includes tools such as GCC, libc,
|
||
Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
|
||
build-system gnu)} module for a complete list.) We call these the
|
||
@dfn{implicit inputs} of a package, because package definitions don't
|
||
have to mention them.
|
||
@end defvr
|
||
|
||
Other @code{<build-system>} objects are defined to support other
|
||
conventions and tools used by free software packages. They inherit most
|
||
of @var{gnu-build-system}, and differ mainly in the set of inputs
|
||
implicitly added to the build process, and in the list of phases
|
||
executed. Some of these build systems are listed below.
|
||
|
||
@defvr {Scheme Variable} cmake-build-system
|
||
This variable is exported by @code{(guix build-system cmake)}. It
|
||
implements the build procedure for packages using the
|
||
@url{http://www.cmake.org, CMake build tool}.
|
||
|
||
It automatically adds the @code{cmake} package to the set of inputs.
|
||
Which package is used can be specified with the @code{#:cmake}
|
||
parameter.
|
||
@end defvr
|
||
|
||
@defvr {Scheme Variable} python-build-system
|
||
This variable is exported by @code{(guix build-system python)}. It
|
||
implements the more or less standard build procedure used by Python
|
||
packages, which consists in running @code{python setup.py build} and
|
||
then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
|
||
|
||
For packages that install stand-alone Python programs under @code{bin/},
|
||
it takes care of wrapping these programs so their @code{PYTHONPATH}
|
||
environment variable points to all the Python libraries they depend on.
|
||
|
||
Which Python package is used can be specified with the @code{#:python}
|
||
parameter.
|
||
@end defvr
|
||
|
||
@defvr {Scheme Variable} perl-build-system
|
||
This variable is exported by @code{(guix build-system perl)}. It
|
||
implements the standard build procedure for Perl packages, which
|
||
consists in running @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}},
|
||
followed by @code{make} and @code{make install}.
|
||
|
||
The initial @code{perl Makefile.PL} invocation passes flags specified by
|
||
the @code{#:make-maker-flags} parameter.
|
||
|
||
Which Perl package is used can be specified with @code{#:perl}.
|
||
@end defvr
|
||
|
||
|
||
Lastly, for packages that do not need anything as sophisticated, a
|
||
``trivial'' build system is provided. It is trivial in the sense that
|
||
it provides basically no support: it does not pull any implicit inputs,
|
||
and does not have a notion of build phases.
|
||
|
||
@defvr {Scheme Variable} trivial-build-system
|
||
This variable is exported by @code{(guix build-system trivial)}.
|
||
|
||
This build system requires a @code{#:builder} argument. This argument
|
||
must be a Scheme expression that builds the package's output(s)---as
|
||
with @code{build-expression->derivation} (@pxref{Derivations,
|
||
@code{build-expression->derivation}}).
|
||
@end defvr
|
||
|
||
@node The Store
|
||
@section The Store
|
||
|
||
@cindex store
|
||
@cindex store paths
|
||
|
||
Conceptually, the @dfn{store} is where derivations that have been
|
||
successfully built are stored---by default, under @file{/gnu/store}.
|
||
Sub-directories in the store are referred to as @dfn{store paths}. The
|
||
store has an associated database that contains information such has the
|
||
store paths referred to by each store path, and the list of @emph{valid}
|
||
store paths---paths that result from a successful build.
|
||
|
||
The store is always accessed by the daemon on behalf of its clients
|
||
(@pxref{Invoking guix-daemon}). To manipulate the store, clients
|
||
connect to the daemon over a Unix-domain socket, send it requests, and
|
||
read the result---these are remote procedure calls, or RPCs.
|
||
|
||
The @code{(guix store)} module provides procedures to connect to the
|
||
daemon, and to perform RPCs. These are described below.
|
||
|
||
@deffn {Scheme Procedure} open-connection [@var{file}] [#:reserve-space? #t]
|
||
Connect to the daemon over the Unix-domain socket at @var{file}. When
|
||
@var{reserve-space?} is true, instruct it to reserve a little bit of
|
||
extra space on the file system so that the garbage collector can still
|
||
operate, should the disk become full. Return a server object.
|
||
|
||
@var{file} defaults to @var{%default-socket-path}, which is the normal
|
||
location given the options that were passed to @command{configure}.
|
||
@end deffn
|
||
|
||
@deffn {Scheme Procedure} close-connection @var{server}
|
||
Close the connection to @var{server}.
|
||
@end deffn
|
||
|
||
@defvr {Scheme Variable} current-build-output-port
|
||
This variable is bound to a SRFI-39 parameter, which refers to the port
|
||
where build and error logs sent by the daemon should be written.
|
||
@end defvr
|
||
|
||
Procedures that make RPCs all take a server object as their first
|
||
argument.
|
||
|
||
@deffn {Scheme Procedure} valid-path? @var{server} @var{path}
|
||
Return @code{#t} when @var{path} is a valid store path.
|
||
@end deffn
|
||
|
||
@deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
|
||
Add @var{text} under file @var{name} in the store, and return its store
|
||
path. @var{references} is the list of store paths referred to by the
|
||
resulting store path.
|
||
@end deffn
|
||
|
||
@deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
|
||
Build @var{derivations} (a list of @code{<derivation>} objects or
|
||
derivation paths), and return when the worker is done building them.
|
||
Return @code{#t} on success.
|
||
@end deffn
|
||
|
||
Note that the @code{(guix monads)} module provides a monad as well as
|
||
monadic versions of the above procedures, with the goal of making it
|
||
more convenient to work with code that accesses the store (@pxref{The
|
||
Store Monad}).
|
||
|
||
@c FIXME
|
||
@i{This section is currently incomplete.}
|
||
|
||
@node Derivations
|
||
@section Derivations
|
||
|
||
@cindex derivations
|
||
Low-level build actions and the environment in which they are performed
|
||
are represented by @dfn{derivations}. A derivation contain the
|
||
following pieces of information:
|
||
|
||
@itemize
|
||
@item
|
||
The outputs of the derivation---derivations produce at least one file or
|
||
directory in the store, but may produce more.
|
||
|
||
@item
|
||
The inputs of the derivations, which may be other derivations or plain
|
||
files in the store (patches, build scripts, etc.)
|
||
|
||
@item
|
||
The system type targeted by the derivation---e.g., @code{x86_64-linux}.
|
||
|
||
@item
|
||
The file name of a build script in the store, along with the arguments
|
||
to be passed.
|
||
|
||
@item
|
||
A list of environment variables to be defined.
|
||
|
||
@end itemize
|
||
|
||
@cindex derivation path
|
||
Derivations allow clients of the daemon to communicate build actions to
|
||
the store. They exist in two forms: as an in-memory representation,
|
||
both on the client- and daemon-side, and as files in the store whose
|
||
name end in @code{.drv}---these files are referred to as @dfn{derivation
|
||
paths}. Derivations paths can be passed to the @code{build-derivations}
|
||
procedure to perform the build actions they prescribe (@pxref{The
|
||
Store}).
|
||
|
||
The @code{(guix derivations)} module provides a representation of
|
||
derivations as Scheme objects, along with procedures to create and
|
||
otherwise manipulate derivations. The lowest-level primitive to create
|
||
a derivation is the @code{derivation} procedure:
|
||
|
||
@deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
|
||
@var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
|
||
[#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
|
||
[#:system (%current-system)] [#:references-graphs #f] @
|
||
[#:allowed-references #f] [#:local-build? #f]
|
||
Build a derivation with the given arguments, and return the resulting
|
||
@code{<derivation>} object.
|
||
|
||
When @var{hash} and @var{hash-algo} are given, a
|
||
@dfn{fixed-output derivation} is created---i.e., one whose result is
|
||
known in advance, such as a file download. If, in addition,
|
||
@var{recursive?} is true, then that fixed output may be an executable
|
||
file or a directory and @var{hash} must be the hash of an archive
|
||
containing this output.
|
||
|
||
When @var{references-graphs} is true, it must be a list of file
|
||
name/store path pairs. In that case, the reference graph of each store
|
||
path is exported in the build environment in the corresponding file, in
|
||
a simple text format.
|
||
|
||
When @var{allowed-references} is true, it must be a list of store items
|
||
or outputs that the derivation's output may refer to.
|
||
|
||
When @var{local-build?} is true, declare that the derivation is not a
|
||
good candidate for offloading and should rather be built locally
|
||
(@pxref{Daemon Offload Setup}). This is the case for small derivations
|
||
where the costs of data transfers would outweigh the benefits.
|
||
@end deffn
|
||
|
||
@noindent
|
||
Here's an example with a shell script as its builder, assuming
|
||
@var{store} is an open connection to the daemon, and @var{bash} points
|
||
to a Bash executable in the store:
|
||
|
||
@lisp
|
||
(use-modules (guix utils)
|
||
(guix store)
|
||
(guix derivations))
|
||
|
||
(let ((builder ; add the Bash script to the store
|
||
(add-text-to-store store "my-builder.sh"
|
||
"echo hello world > $out\n" '())))
|
||
(derivation store "foo"
|
||
bash `("-e" ,builder)
|
||
#:inputs `((,bash) (,builder))
|
||
#:env-vars '(("HOME" . "/homeless"))))
|
||
@result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
|
||
@end lisp
|
||
|
||
As can be guessed, this primitive is cumbersome to use directly. A
|
||
better approach is to write build scripts in Scheme, of course! The
|
||
best course of action for that is to write the build code as a
|
||
``G-expression'', and to pass it to @code{gexp->derivation}. For more
|
||
information, @pxref{G-Expressions}.
|
||
|
||
Once upon a time, @code{gexp->derivation} did not exist and constructing
|
||
derivations with build code written in Scheme was achieved with
|
||
@code{build-expression->derivation}, documented below. This procedure
|
||
is now deprecated in favor of the much nicer @code{gexp->derivation}.
|
||
|
||
@deffn {Scheme Procedure} build-expression->derivation @var{store} @
|
||
@var{name} @var{exp} @
|
||
[#:system (%current-system)] [#:inputs '()] @
|
||
[#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
|
||
[#:recursive? #f] [#:env-vars '()] [#:modules '()] @
|
||
[#:references-graphs #f] [#:allowed-references #f] @
|
||
[#:local-build? #f] [#:guile-for-build #f]
|
||
Return a derivation that executes Scheme expression @var{exp} as a
|
||
builder for derivation @var{name}. @var{inputs} must be a list of
|
||
@code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
|
||
@code{"out"} is assumed. @var{modules} is a list of names of Guile
|
||
modules from the current search path to be copied in the store,
|
||
compiled, and made available in the load path during the execution of
|
||
@var{exp}---e.g., @code{((guix build utils) (guix build
|
||
gnu-build-system))}.
|
||
|
||
@var{exp} is evaluated in an environment where @code{%outputs} is bound
|
||
to a list of output/path pairs, and where @code{%build-inputs} is bound
|
||
to a list of string/output-path pairs made from @var{inputs}.
|
||
Optionally, @var{env-vars} is a list of string pairs specifying the name
|
||
and value of environment variables visible to the builder. The builder
|
||
terminates by passing the result of @var{exp} to @code{exit}; thus, when
|
||
@var{exp} returns @code{#f}, the build is considered to have failed.
|
||
|
||
@var{exp} is built using @var{guile-for-build} (a derivation). When
|
||
@var{guile-for-build} is omitted or is @code{#f}, the value of the
|
||
@code{%guile-for-build} fluid is used instead.
|
||
|
||
See the @code{derivation} procedure for the meaning of
|
||
@var{references-graphs}, @var{allowed-references}, and @var{local-build?}.
|
||
@end deffn
|
||
|
||
@noindent
|
||
Here's an example of a single-output derivation that creates a directory
|
||
containing one file:
|
||
|
||
@lisp
|
||
(let ((builder '(let ((out (assoc-ref %outputs "out")))
|
||
(mkdir out) ; create /gnu/store/@dots{}-goo
|
||
(call-with-output-file (string-append out "/test")
|
||
(lambda (p)
|
||
(display '(hello guix) p))))))
|
||
(build-expression->derivation store "goo" builder))
|
||
|
||
@result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
|
||
@end lisp
|
||
|
||
|
||
@node The Store Monad
|
||
@section The Store Monad
|
||
|
||
@cindex monad
|
||
|
||
The procedures that operate on the store described in the previous
|
||
sections all take an open connection to the build daemon as their first
|
||
argument. Although the underlying model is functional, they either have
|
||
side effects or depend on the current state of the store.
|
||
|
||
The former is inconvenient: the connection to the build daemon has to be
|
||
carried around in all those functions, making it impossible to compose
|
||
functions that do not take that parameter with functions that do. The
|
||
latter can be problematic: since store operations have side effects
|
||
and/or depend on external state, they have to be properly sequenced.
|
||
|
||
@cindex monadic values
|
||
@cindex monadic functions
|
||
This is where the @code{(guix monads)} module comes in. This module
|
||
provides a framework for working with @dfn{monads}, and a particularly
|
||
useful monad for our uses, the @dfn{store monad}. Monads are a
|
||
construct that allows two things: associating ``context'' with values
|
||
(in our case, the context is the store), and building sequences of
|
||
computations (here computations includes accesses to the store.) Values
|
||
in a monad---values that carry this additional context---are called
|
||
@dfn{monadic values}; procedures that return such values are called
|
||
@dfn{monadic procedures}.
|
||
|
||
Consider this ``normal'' procedure:
|
||
|
||
@example
|
||
(define (sh-symlink store)
|
||
;; Return a derivation that symlinks the 'bash' executable.
|
||
(let* ((drv (package-derivation store bash))
|
||
(out (derivation->output-path drv))
|
||
(sh (string-append out "/bin/bash")))
|
||
(build-expression->derivation store "sh"
|
||
`(symlink ,sh %output))))
|
||
@end example
|
||
|
||
Using @code{(guix monads)}, it may be rewritten as a monadic function:
|
||
|
||
@c FIXME: Find a better example, one that uses 'mlet'.
|
||
@example
|
||
(define (sh-symlink)
|
||
;; Same, but return a monadic value.
|
||
(gexp->derivation "sh"
|
||
#~(symlink (string-append #$bash "/bin/bash") #$output)))
|
||
@end example
|
||
|
||
There are two things to note in the second version: the @code{store}
|
||
parameter is now implicit, and the monadic value returned by
|
||
@code{package-file}---a wrapper around @code{package-derivation} and
|
||
@code{derivation->output-path}---is @dfn{bound} using @code{mlet}
|
||
instead of plain @code{let}.
|
||
|
||
Calling the monadic @code{profile.sh} has no effect. To get the desired
|
||
effect, one must use @code{run-with-store}:
|
||
|
||
@example
|
||
(run-with-store (open-connection) (profile.sh))
|
||
@result{} /gnu/store/...-profile.sh
|
||
@end example
|
||
|
||
Note that the @code{(guix monad-repl)} module extends Guile's REPL with
|
||
new ``meta-commands'' to make it easier to deal with monadic procedures:
|
||
@code{run-in-store}, and @code{enter-store-monad}. The former, is used
|
||
to ``run'' a single monadic value through the store:
|
||
|
||
@example
|
||
scheme@@(guile-user)> ,run-in-store (package->derivation hello)
|
||
$1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
|
||
@end example
|
||
|
||
The latter enters a recursive REPL, where all the return values are
|
||
automatically run through the store:
|
||
|
||
@example
|
||
scheme@@(guile-user)> ,enter-store-monad
|
||
store-monad@@(guile-user) [1]> (package->derivation hello)
|
||
$2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
|
||
store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
|
||
$3 = "/gnu/store/@dots{}-foo"
|
||
store-monad@@(guile-user) [1]> ,q
|
||
scheme@@(guile-user)>
|
||
@end example
|
||
|
||
@noindent
|
||
Note that non-monadic values cannot be returned in the
|
||
@code{store-monad} REPL.
|
||
|
||
The main syntactic forms to deal with monads in general are described
|
||
below.
|
||
|
||
@deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
|
||
Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
|
||
in @var{monad}.
|
||
@end deffn
|
||
|
||
@deffn {Scheme Syntax} return @var{val}
|
||
Return a monadic value that encapsulates @var{val}.
|
||
@end deffn
|
||
|
||
@deffn {Scheme Syntax} >>= @var{mval} @var{mproc}
|
||
@dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
|
||
procedure @var{mproc}@footnote{This operation is commonly referred to as
|
||
``bind'', but that name denotes an unrelated procedure in Guile. Thus
|
||
we use this somewhat cryptic symbol inherited from the Haskell
|
||
language.}.
|
||
@end deffn
|
||
|
||
@deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
|
||
@var{body} ...
|
||
@deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
|
||
@var{body} ...
|
||
Bind the variables @var{var} to the monadic values @var{mval} in
|
||
@var{body}. The form (@var{var} -> @var{val}) binds @var{var} to the
|
||
``normal'' value @var{val}, as per @code{let}.
|
||
|
||
@code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
|
||
(@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
|
||
@end deffn
|
||
|
||
The interface to the store monad provided by @code{(guix monads)} is as
|
||
follows.
|
||
|
||
@defvr {Scheme Variable} %store-monad
|
||
The store monad. Values in the store monad encapsulate accesses to the
|
||
store. When its effect is needed, a value of the store monad must be
|
||
``evaluated'' by passing it to the @code{run-with-store} procedure (see
|
||
below.)
|
||
@end defvr
|
||
|
||
@deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
|
||
Run @var{mval}, a monadic value in the store monad, in @var{store}, an
|
||
open store connection.
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} text-file @var{name} @var{text}
|
||
Return as a monadic value the absolute file name in the store of the file
|
||
containing @var{text}, a string.
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
|
||
Return as a monadic value a derivation that builds a text file
|
||
containing all of @var{text}. @var{text} may list, in addition to
|
||
strings, packages, derivations, and store file names; the resulting
|
||
store file holds references to all these.
|
||
|
||
This variant should be preferred over @code{text-file} anytime the file
|
||
to create will reference items from the store. This is typically the
|
||
case when building a configuration file that embeds store file names,
|
||
like this:
|
||
|
||
@example
|
||
(define (profile.sh)
|
||
;; Return the name of a shell script in the store that
|
||
;; initializes the 'PATH' environment variable.
|
||
(text-file* "profile.sh"
|
||
"export PATH=" coreutils "/bin:"
|
||
grep "/bin:" sed "/bin\n"))
|
||
@end example
|
||
|
||
In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
|
||
will references @var{coreutils}, @var{grep}, and @var{sed}, thereby
|
||
preventing them from being garbage-collected during its lifetime.
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
|
||
[#:recursive? #t]
|
||
Return the name of @var{file} once interned in the store. Use
|
||
@var{name} as its store name, or the basename of @var{file} if
|
||
@var{name} is omitted.
|
||
|
||
When @var{recursive?} is true, the contents of @var{file} are added
|
||
recursively; if @var{file} designates a flat file and @var{recursive?}
|
||
is true, its contents are added, and its permission bits are kept.
|
||
|
||
The example below adds a file to the store, under two different names:
|
||
|
||
@example
|
||
(run-with-store (open-connection)
|
||
(mlet %store-monad ((a (interned-file "README"))
|
||
(b (interned-file "README" "LEGU-MIN")))
|
||
(return (list a b))))
|
||
|
||
@result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
|
||
@end example
|
||
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
|
||
[#:system (%current-system)] [#:target #f] @
|
||
[#:output "out"] Return as a monadic
|
||
value in the absolute file name of @var{file} within the @var{output}
|
||
directory of @var{package}. When @var{file} is omitted, return the name
|
||
of the @var{output} directory of @var{package}. When @var{target} is
|
||
true, use it as a cross-compilation target triplet.
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
|
||
@deffnx {Monadic Procedure} package->cross-derivation @var{package} @
|
||
@var{target} [@var{system}]
|
||
Monadic version of @code{package-derivation} and
|
||
@code{package-cross-derivation} (@pxref{Defining Packages}).
|
||
@end deffn
|
||
|
||
|
||
@node G-Expressions
|
||
@section G-Expressions
|
||
|
||
@cindex G-expression
|
||
@cindex build code quoting
|
||
So we have ``derivations'', which represent a sequence of build actions
|
||
to be performed to produce an item in the store (@pxref{Derivations}).
|
||
Those build actions are performed when asking the daemon to actually
|
||
build the derivations; they are run by the daemon in a container
|
||
(@pxref{Invoking guix-daemon}).
|
||
|
||
@cindex strata of code
|
||
It should come as no surprise that we like to write those build actions
|
||
in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
|
||
code@footnote{The term @dfn{stratum} in this context was coined by
|
||
Manuel Serrano et al.@: in the context of their work on Hop. Oleg
|
||
Kiselyov, who has written insightful
|
||
@url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
|
||
on this topic}, refers to this kind of code generation as
|
||
@dfn{staging}.}: the ``host code''---code that defines packages, talks
|
||
to the daemon, etc.---and the ``build code''---code that actually
|
||
performs build actions, such as making directories, invoking
|
||
@command{make}, etc.
|
||
|
||
To describe a derivation and its build actions, one typically needs to
|
||
embed build code inside host code. It boils down to manipulating build
|
||
code as data, and Scheme's homoiconicity---code has a direct
|
||
representation as data---comes in handy for that. But we need more than
|
||
Scheme's normal @code{quasiquote} mechanism to construct build
|
||
expressions.
|
||
|
||
The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
|
||
S-expressions adapted to build expressions. G-expressions, or
|
||
@dfn{gexps}, consist essentially in three syntactic forms: @code{gexp},
|
||
@code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
|
||
@code{#$}, and @code{#$@@}), which are comparable respectively to
|
||
@code{quasiquote}, @code{unquote}, and @code{unquote-splicing}
|
||
(@pxref{Expression Syntax, @code{quasiquote},, guile, GNU Guile
|
||
Reference Manual}). However, there are major differences:
|
||
|
||
@itemize
|
||
@item
|
||
Gexps are meant to be written to a file and run or manipulated by other
|
||
processes.
|
||
|
||
@item
|
||
When a package or derivation is unquoted inside a gexp, the result is as
|
||
if its output file name had been introduced.
|
||
|
||
@item
|
||
Gexps carry information about the packages or derivations they refer to,
|
||
and these dependencies are automatically added as inputs to the build
|
||
processes that use them.
|
||
@end itemize
|
||
|
||
To illustrate the idea, here is an example of a gexp:
|
||
|
||
@example
|
||
(define build-exp
|
||
#~(begin
|
||
(mkdir #$output)
|
||
(chdir #$output)
|
||
(symlink (string-append #$coreutils "/bin/ls")
|
||
"list-files")))
|
||
@end example
|
||
|
||
This gexp can be passed to @code{gexp->derivation}; we obtain a
|
||
derivation that builds a directory containing exactly one symlink to
|
||
@file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
|
||
|
||
@example
|
||
(gexp->derivation "the-thing" build-exp)
|
||
@end example
|
||
|
||
As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
|
||
substituted to the reference to the @var{coreutils} package in the
|
||
actual build code, and @var{coreutils} is automatically made an input to
|
||
the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
|
||
output)}) is replaced by a string containing the derivation's output
|
||
directory name.
|
||
|
||
@cindex cross compilation
|
||
In a cross-compilation context, it is useful to distinguish between
|
||
references to the @emph{native} build of a package---that can run on the
|
||
host---versus references to cross builds of a package. To that end, the
|
||
@code{#+} plays the same role as @code{#$}, but is a reference to a
|
||
native package build:
|
||
|
||
@example
|
||
(gexp->derivation "vi"
|
||
#~(begin
|
||
(mkdir #$output)
|
||
(system* (string-append #+coreutils "/bin/ln")
|
||
"-s"
|
||
(string-append #$emacs "/bin/emacs")
|
||
(string-append #$output "/bin/vi")))
|
||
#:target "mips64el-linux")
|
||
@end example
|
||
|
||
@noindent
|
||
In the example above, the native build of @var{coreutils} is used, so
|
||
that @command{ln} can actually run on the host; but then the
|
||
cross-compiled build of @var{emacs} is referenced.
|
||
|
||
The syntactic form to construct gexps is summarized below.
|
||
|
||
@deffn {Scheme Syntax} #~@var{exp}
|
||
@deffnx {Scheme Syntax} (gexp @var{exp})
|
||
Return a G-expression containing @var{exp}. @var{exp} may contain one
|
||
or more of the following forms:
|
||
|
||
@table @code
|
||
@item #$@var{obj}
|
||
@itemx (ungexp @var{obj})
|
||
Introduce a reference to @var{obj}. @var{obj} may be a package or a
|
||
derivation, in which case the @code{ungexp} form is replaced by its
|
||
output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
|
||
|
||
If @var{obj} is a list, it is traversed and any package or derivation
|
||
references are substituted similarly.
|
||
|
||
If @var{obj} is another gexp, its contents are inserted and its
|
||
dependencies are added to those of the containing gexp.
|
||
|
||
If @var{obj} is another kind of object, it is inserted as is.
|
||
|
||
@item #$@var{package-or-derivation}:@var{output}
|
||
@itemx (ungexp @var{package-or-derivation} @var{output})
|
||
This is like the form above, but referring explicitly to the
|
||
@var{output} of @var{package-or-derivation}---this is useful when
|
||
@var{package-or-derivation} produces multiple outputs (@pxref{Packages
|
||
with Multiple Outputs}).
|
||
|
||
@item #+@var{obj}
|
||
@itemx #+@var{obj}:output
|
||
@itemx (ungexp-native @var{obj})
|
||
@itemx (ungexp-native @var{obj} @var{output})
|
||
Same as @code{ungexp}, but produces a reference to the @emph{native}
|
||
build of @var{obj} when used in a cross compilation context.
|
||
|
||
@item #$output[:@var{output}]
|
||
@itemx (ungexp output [@var{output}])
|
||
Insert a reference to derivation output @var{output}, or to the main
|
||
output when @var{output} is omitted.
|
||
|
||
This only makes sense for gexps passed to @code{gexp->derivation}.
|
||
|
||
@item #$@@@var{lst}
|
||
@itemx (ungexp-splicing @var{lst})
|
||
Like the above, but splices the contents of @var{lst} inside the
|
||
containing list.
|
||
|
||
@item #+@@@var{lst}
|
||
@itemx (ungexp-native-splicing @var{lst})
|
||
Like the above, but refers to native builds of the objects listed in
|
||
@var{lst}.
|
||
|
||
@end table
|
||
|
||
G-expressions created by @code{gexp} or @code{#~} are run-time objects
|
||
of the @code{gexp?} type (see below.)
|
||
@end deffn
|
||
|
||
@deffn {Scheme Procedure} gexp? @var{obj}
|
||
Return @code{#t} if @var{obj} is a G-expression.
|
||
@end deffn
|
||
|
||
G-expressions are meant to be written to disk, either as code building
|
||
some derivation, or as plain files in the store. The monadic procedures
|
||
below allow you to do that (@pxref{The Store Monad}, for more
|
||
information about monads.)
|
||
|
||
@deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
|
||
[#:system (%current-system)] [#:target #f] [#:inputs '()] @
|
||
[#:hash #f] [#:hash-algo #f] @
|
||
[#:recursive? #f] [#:env-vars '()] [#:modules '()] @
|
||
[#:references-graphs #f] [#:local-build? #f] @
|
||
[#:guile-for-build #f]
|
||
Return a derivation @var{name} that runs @var{exp} (a gexp) with
|
||
@var{guile-for-build} (a derivation) on @var{system}. When @var{target}
|
||
is true, it is used as the cross-compilation target triplet for packages
|
||
referred to by @var{exp}.
|
||
|
||
Make @var{modules} available in the evaluation context of @var{EXP};
|
||
@var{MODULES} is a list of names of Guile modules from the current
|
||
search path to be copied in the store, compiled, and made available in
|
||
the load path during the execution of @var{exp}---e.g., @code{((guix
|
||
build utils) (guix build gnu-build-system))}.
|
||
|
||
The other arguments are as for @code{derivation} (@pxref{Derivations}).
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
|
||
Return an executable script @var{name} that runs @var{exp} using
|
||
@var{guile} with @var{modules} in its search path.
|
||
|
||
The example below builds a script that simply invokes the @command{ls}
|
||
command:
|
||
|
||
@example
|
||
(use-modules (guix gexp) (gnu packages base))
|
||
|
||
(gexp->script "list-files"
|
||
#~(execl (string-append #$coreutils "/bin/ls")
|
||
"ls"))
|
||
@end example
|
||
|
||
When ``running'' it through the store (@pxref{The Store Monad,
|
||
@code{run-with-store}}), we obtain a derivation that produces an
|
||
executable file @file{/gnu/store/@dots{}-list-files} along these lines:
|
||
|
||
@example
|
||
#!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
|
||
!#
|
||
(execl (string-append "/gnu/store/@dots{}-coreutils-8.22"/bin/ls")
|
||
"ls")
|
||
@end example
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} gexp->file @var{name} @var{exp}
|
||
Return a derivation that builds a file @var{name} containing @var{exp}.
|
||
|
||
The resulting file holds references to all the dependencies of @var{exp}
|
||
or a subset thereof.
|
||
@end deffn
|
||
|
||
Of course, in addition to gexps embedded in ``host'' code, there are
|
||
also modules containing build tools. To make it clear that they are
|
||
meant to be used in the build stratum, these modules are kept in the
|
||
@code{(guix build @dots{})} name space.
|
||
|
||
|
||
@c *********************************************************************
|
||
@node Utilities
|
||
@chapter Utilities
|
||
|
||
This section describes tools primarily targeted at developers and users
|
||
who write new package definitions. They complement the Scheme
|
||
programming interface of Guix in a convenient way.
|
||
|
||
@menu
|
||
* Invoking guix build:: Building packages from the command line.
|
||
* Invoking guix download:: Downloading a file and printing its hash.
|
||
* Invoking guix hash:: Computing the cryptographic hash of a file.
|
||
* Invoking guix refresh:: Updating package definitions.
|
||
@end menu
|
||
|
||
@node Invoking guix build
|
||
@section Invoking @command{guix build}
|
||
|
||
The @command{guix build} command builds packages or derivations and
|
||
their dependencies, and prints the resulting store paths. Note that it
|
||
does not modify the user's profile---this is the job of the
|
||
@command{guix package} command (@pxref{Invoking guix package}). Thus,
|
||
it is mainly useful for distribution developers.
|
||
|
||
The general syntax is:
|
||
|
||
@example
|
||
guix build @var{options} @var{package-or-derivation}@dots{}
|
||
@end example
|
||
|
||
@var{package-or-derivation} may be either the name of a package found in
|
||
the software distribution such as @code{coreutils} or
|
||
@code{coreutils-8.20}, or a derivation such as
|
||
@file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
|
||
package with the corresponding name (and optionally version) is searched
|
||
for among the GNU distribution modules (@pxref{Package Modules}).
|
||
|
||
Alternatively, the @code{--expression} option may be used to specify a
|
||
Scheme expression that evaluates to a package; this is useful when
|
||
disambiguation among several same-named packages or package variants is
|
||
needed.
|
||
|
||
The @var{options} may be zero or more of the following:
|
||
|
||
@table @code
|
||
|
||
@item --expression=@var{expr}
|
||
@itemx -e @var{expr}
|
||
Build the package or derivation @var{expr} evaluates to.
|
||
|
||
For example, @var{expr} may be @code{(@@ (gnu packages guile)
|
||
guile-1.8)}, which unambiguously designates this specific variant of
|
||
version 1.8 of Guile.
|
||
|
||
Alternately, @var{expr} may be a G-expression, in which case it is used
|
||
as a build program passed to @code{gexp->derivation}
|
||
(@pxref{G-Expressions}).
|
||
|
||
Lastly, @var{expr} may refer to a zero-argument monadic procedure
|
||
(@pxref{The Store Monad}). The procedure must return a derivation as a
|
||
monadic value, which is then passed through @code{run-with-store}.
|
||
|
||
@item --source
|
||
@itemx -S
|
||
Build the packages' source derivations, rather than the packages
|
||
themselves.
|
||
|
||
For instance, @code{guix build -S gcc} returns something like
|
||
@file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is GCC's source tarball.
|
||
|
||
The returned source tarball is the result of applying any patches and
|
||
code snippets specified in the package's @code{origin} (@pxref{Defining
|
||
Packages}).
|
||
|
||
@item --system=@var{system}
|
||
@itemx -s @var{system}
|
||
Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
|
||
the host's system type.
|
||
|
||
An example use of this is on Linux-based systems, which can emulate
|
||
different personalities. For instance, passing
|
||
@code{--system=i686-linux} on an @code{x86_64-linux} system allows users
|
||
to build packages in a complete 32-bit environment.
|
||
|
||
@item --target=@var{triplet}
|
||
@cindex cross-compilation
|
||
Cross-build for @var{triplet}, which must be a valid GNU triplet, such
|
||
as @code{"mips64el-linux-gnu"} (@pxref{Configuration Names, GNU
|
||
configuration triplets,, configure, GNU Configure and Build System}).
|
||
|
||
@item --with-source=@var{source}
|
||
Use @var{source} as the source of the corresponding package.
|
||
@var{source} must be a file name or a URL, as for @command{guix
|
||
download} (@pxref{Invoking guix download}).
|
||
|
||
The ``corresponding package'' is taken to be one specified on the
|
||
command line whose name matches the base of @var{source}---e.g., if
|
||
@var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
|
||
package is @code{guile}. Likewise, the version string is inferred from
|
||
@var{source}; in the previous example, it's @code{2.0.10}.
|
||
|
||
This option allows users to try out versions of packages other than the
|
||
one provided by the distribution. The example below downloads
|
||
@file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
|
||
the @code{ed} package:
|
||
|
||
@example
|
||
guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
|
||
@end example
|
||
|
||
As a developer, @code{--with-source} makes it easy to test release
|
||
candidates:
|
||
|
||
@example
|
||
guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
|
||
@end example
|
||
|
||
|
||
@item --derivations
|
||
@itemx -d
|
||
Return the derivation paths, not the output paths, of the given
|
||
packages.
|
||
|
||
@item --root=@var{file}
|
||
@itemx -r @var{file}
|
||
Make @var{file} a symlink to the result, and register it as a garbage
|
||
collector root.
|
||
|
||
@item --log-file
|
||
Return the build log file names for the given
|
||
@var{package-or-derivation}s, or raise an error if build logs are
|
||
missing.
|
||
|
||
This works regardless of how packages or derivations are specified. For
|
||
instance, the following invocations are equivalent:
|
||
|
||
@example
|
||
guix build --log-file `guix build -d guile`
|
||
guix build --log-file `guix build guile`
|
||
guix build --log-file guile
|
||
guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
|
||
@end example
|
||
|
||
|
||
@end table
|
||
|
||
@cindex common build options
|
||
In addition, a number of options that control the build process are
|
||
common to @command{guix build} and other commands that can spawn builds,
|
||
such as @command{guix package} or @command{guix archive}. These are the
|
||
following:
|
||
|
||
@table @code
|
||
|
||
@item --keep-failed
|
||
@itemx -K
|
||
Keep the build tree of failed builds. Thus, if a build fail, its build
|
||
tree is kept under @file{/tmp}, in a directory whose name is shown at
|
||
the end of the build log. This is useful when debugging build issues.
|
||
|
||
@item --dry-run
|
||
@itemx -n
|
||
Do not build the derivations.
|
||
|
||
@item --fallback
|
||
When substituting a pre-built binary fails, fall back to building
|
||
packages locally.
|
||
|
||
@item --no-substitutes
|
||
Do not use substitutes for build products. That is, always build things
|
||
locally instead of allowing downloads of pre-built binaries
|
||
(@pxref{Substitutes}).
|
||
|
||
@item --no-build-hook
|
||
Do not attempt to offload builds @i{via} the daemon's ``build hook''
|
||
(@pxref{Daemon Offload Setup}). That is, always build things locally
|
||
instead of offloading builds to remote machines.
|
||
|
||
@item --max-silent-time=@var{seconds}
|
||
When the build or substitution process remains silent for more than
|
||
@var{seconds}, terminate it and report a build failure.
|
||
|
||
@item --timeout=@var{seconds}
|
||
Likewise, when the build or substitution process lasts for more than
|
||
@var{seconds}, terminate it and report a build failure.
|
||
|
||
By default there is no timeout. This behavior can be restored with
|
||
@code{--timeout=0}.
|
||
|
||
@item --verbosity=@var{level}
|
||
Use the given verbosity level. @var{level} must be an integer between 0
|
||
and 5; higher means more verbose output. Setting a level of 4 or more
|
||
may be helpful when debugging setup issues with the build daemon.
|
||
|
||
@item --cores=@var{n}
|
||
@itemx -c @var{n}
|
||
Allow the use of up to @var{n} CPU cores for the build. The special
|
||
value @code{0} means to use as many CPU cores as available.
|
||
|
||
@end table
|
||
|
||
Behind the scenes, @command{guix build} is essentially an interface to
|
||
the @code{package-derivation} procedure of the @code{(guix packages)}
|
||
module, and to the @code{build-derivations} procedure of the @code{(guix
|
||
store)} module.
|
||
|
||
@node Invoking guix download
|
||
@section Invoking @command{guix download}
|
||
|
||
When writing a package definition, developers typically need to download
|
||
the package's source tarball, compute its SHA256 hash, and write that
|
||
hash in the package definition (@pxref{Defining Packages}). The
|
||
@command{guix download} tool helps with this task: it downloads a file
|
||
from the given URI, adds it to the store, and prints both its file name
|
||
in the store and its SHA256 hash.
|
||
|
||
The fact that the downloaded file is added to the store saves bandwidth:
|
||
when the developer eventually tries to build the newly defined package
|
||
with @command{guix build}, the source tarball will not have to be
|
||
downloaded again because it is already in the store. It is also a
|
||
convenient way to temporarily stash files, which may be deleted
|
||
eventually (@pxref{Invoking guix gc}).
|
||
|
||
The @command{guix download} command supports the same URIs as used in
|
||
package definitions. In particular, it supports @code{mirror://} URIs.
|
||
@code{https} URIs (HTTP over TLS) are supported @emph{provided} the
|
||
Guile bindings for GnuTLS are available in the user's environment; when
|
||
they are not available, an error is raised.
|
||
|
||
The following option is available:
|
||
|
||
@table @code
|
||
@item --format=@var{fmt}
|
||
@itemx -f @var{fmt}
|
||
Write the hash in the format specified by @var{fmt}. For more
|
||
information on the valid values for @var{fmt}, @ref{Invoking guix hash}.
|
||
@end table
|
||
|
||
@node Invoking guix hash
|
||
@section Invoking @command{guix hash}
|
||
|
||
The @command{guix hash} command computes the SHA256 hash of a file.
|
||
It is primarily a convenience tool for anyone contributing to the
|
||
distribution: it computes the cryptographic hash of a file, which can be
|
||
used in the definition of a package (@pxref{Defining Packages}).
|
||
|
||
The general syntax is:
|
||
|
||
@example
|
||
guix hash @var{option} @var{file}
|
||
@end example
|
||
|
||
@command{guix hash} has the following option:
|
||
|
||
@table @code
|
||
|
||
@item --format=@var{fmt}
|
||
@itemx -f @var{fmt}
|
||
Write the hash in the format specified by @var{fmt}.
|
||
|
||
Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
|
||
(@code{hex} and @code{hexadecimal} can be used as well).
|
||
|
||
If the @option{--format} option is not specified, @command{guix hash}
|
||
will output the hash in @code{nix-base32}. This representation is used
|
||
in the definitions of packages.
|
||
|
||
@item --recursive
|
||
@itemx -r
|
||
Compute the hash on @var{file} recursively.
|
||
|
||
In this case, the hash is computed on an archive containing @var{file},
|
||
including its children if it is a directory. Some of @var{file}'s
|
||
meta-data is part of the archive; for instance, when @var{file} is a
|
||
regular file, the hash is different depending on whether @var{file} is
|
||
executable or not. Meta-data such as time stamps has no impact on the
|
||
hash (@pxref{Invoking guix archive}).
|
||
@c FIXME: Replace xref above with xref to an ``Archive'' section when
|
||
@c it exists.
|
||
|
||
@end table
|
||
|
||
@node Invoking guix refresh
|
||
@section Invoking @command{guix refresh}
|
||
|
||
The primary audience of the @command{guix refresh} command is developers
|
||
of the GNU software distribution. By default, it reports any packages
|
||
provided by the distribution that are outdated compared to the latest
|
||
upstream version, like this:
|
||
|
||
@example
|
||
$ guix refresh
|
||
gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
|
||
gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
|
||
@end example
|
||
|
||
It does so by browsing each package's FTP directory and determining the
|
||
highest version number of the source tarballs
|
||
therein@footnote{Currently, this only works for GNU packages.}.
|
||
|
||
When passed @code{--update}, it modifies distribution source files to
|
||
update the version numbers and source tarball hashes of those packages'
|
||
recipes (@pxref{Defining Packages}). This is achieved by downloading
|
||
each package's latest source tarball and its associated OpenPGP
|
||
signature, authenticating the downloaded tarball against its signature
|
||
using @command{gpg}, and finally computing its hash. When the public
|
||
key used to sign the tarball is missing from the user's keyring, an
|
||
attempt is made to automatically retrieve it from a public key server;
|
||
when it's successful, the key is added to the user's keyring; otherwise,
|
||
@command{guix refresh} reports an error.
|
||
|
||
The following options are supported:
|
||
|
||
@table @code
|
||
|
||
@item --update
|
||
@itemx -u
|
||
Update distribution source files (package recipes) in place.
|
||
@ref{Defining Packages}, for more information on package definitions.
|
||
|
||
@item --select=[@var{subset}]
|
||
@itemx -s @var{subset}
|
||
Select all the packages in @var{subset}, one of @code{core} or
|
||
@code{non-core}.
|
||
|
||
The @code{core} subset refers to all the packages at the core of the
|
||
distribution---i.e., packages that are used to build ``everything
|
||
else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
|
||
changing one of these packages in the distribution entails a rebuild of
|
||
all the others. Thus, such updates are an inconvenience to users in
|
||
terms of build time or bandwidth used to achieve the upgrade.
|
||
|
||
The @code{non-core} subset refers to the remaining packages. It is
|
||
typically useful in cases where an update of the core packages would be
|
||
inconvenient.
|
||
|
||
@end table
|
||
|
||
In addition, @command{guix refresh} can be passed one or more package
|
||
names, as in this example:
|
||
|
||
@example
|
||
guix refresh -u emacs idutils
|
||
@end example
|
||
|
||
@noindent
|
||
The command above specifically updates the @code{emacs} and
|
||
@code{idutils} packages. The @code{--select} option would have no
|
||
effect in this case.
|
||
|
||
When considering whether to upgrade a package, it is sometimes
|
||
convenient to know which packages would be affected by the upgrade and
|
||
should be checked for compatibility. For this the following option may
|
||
be used when passing @command{guix refresh} one or more package names:
|
||
|
||
@table @code
|
||
|
||
@item --list-dependent
|
||
@itemx -l
|
||
List top-level dependent packages that would need to be rebuilt as a
|
||
result of upgrading one or more packages.
|
||
|
||
@end table
|
||
|
||
Be aware that the @code{--list-dependent} option only
|
||
@emph{approximates} the rebuilds that would be required as a result of
|
||
an upgrade. More rebuilds might be required under some circumstances.
|
||
|
||
@example
|
||
$ guix refresh --list-dependent flex
|
||
Building the following 120 packages would ensure 213 dependent packages are rebuilt:
|
||
hop-2.4.0 geiser-0.4 notmuch-0.18 mu-0.9.9.5 cflow-1.4 idutils-4.6 @dots{}
|
||
@end example
|
||
|
||
The command above lists a set of packages that could be built to check
|
||
for compatibility with an upgraded @code{flex} package.
|
||
|
||
The following options can be used to customize GnuPG operation:
|
||
|
||
@table @code
|
||
|
||
@item --key-server=@var{host}
|
||
Use @var{host} as the OpenPGP key server when importing a public key.
|
||
|
||
@item --gpg=@var{command}
|
||
Use @var{command} as the GnuPG 2.x command. @var{command} is searched
|
||
for in @code{$PATH}.
|
||
|
||
@end table
|
||
|
||
|
||
@c *********************************************************************
|
||
@node GNU Distribution
|
||
@chapter GNU Distribution
|
||
|
||
Guix comes with a distribution of free software@footnote{The term
|
||
``free'' here refers to the
|
||
@url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
|
||
users of that software}.} that forms the basis of the GNU system. This
|
||
includes core GNU packages such as GNU libc, GCC, and Binutils, as well
|
||
as many GNU and non-GNU applications. The complete list of available
|
||
packages can be browsed
|
||
@url{http://www.gnu.org/software/guix/package-list.html,on-line} or by
|
||
running @command{guix package} (@pxref{Invoking guix package}):
|
||
|
||
@example
|
||
guix package --list-available
|
||
@end example
|
||
|
||
Our goal is to build a practical 100% free software distribution of
|
||
Linux-based and other variants of GNU, with a focus on the promotion and
|
||
tight integration of GNU components, and an emphasis on programs and
|
||
tools that help users exert that freedom.
|
||
|
||
The GNU distribution is currently available on the following platforms:
|
||
|
||
@table @code
|
||
|
||
@item x86_64-linux
|
||
Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
|
||
|
||
@item i686-linux
|
||
Intel 32-bit architecture (IA32), Linux-Libre kernel;
|
||
|
||
@item mips64el-linux
|
||
little-endian 64-bit MIPS processors, specifically the Loongson series,
|
||
n32 application binary interface (ABI), and Linux-Libre kernel.
|
||
|
||
@end table
|
||
|
||
@noindent
|
||
For information on porting to other architectures or kernels,
|
||
@xref{Porting}.
|
||
|
||
@menu
|
||
* System Installation:: Installing the whole operating system.
|
||
* System Configuration:: Configuring a GNU system.
|
||
* Installing Debugging Files:: Feeding the debugger.
|
||
* Package Modules:: Packages from the programmer's viewpoint.
|
||
* Packaging Guidelines:: Growing the distribution.
|
||
* Bootstrapping:: GNU/Linux built from scratch.
|
||
* Porting:: Targeting another platform or kernel.
|
||
@end menu
|
||
|
||
Building this distribution is a cooperative effort, and you are invited
|
||
to join! @ref{Contributing}, for information about how you can help.
|
||
|
||
@node System Installation
|
||
@section System Installation
|
||
|
||
This section explains how to install the complete GNU operating system
|
||
on a machine. The Guix package manager can also be installed on top of
|
||
a running GNU/Linux system, @pxref{Installation}.
|
||
|
||
@ifinfo
|
||
@c This paragraph is for people reading this from tty2 of the
|
||
@c installation image.
|
||
You're reading this documentation with an Info reader. For details on
|
||
how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
|
||
link that follows: @pxref{Help,,, info, Info: An Introduction}. Hit
|
||
@kbd{l} afterwards to come back here.
|
||
@end ifinfo
|
||
|
||
@subsection Limitations
|
||
|
||
As of version @value{VERSION}, GNU@tie{}Guix and the GNU system
|
||
distribution are alpha software. It may contain bugs and lack important
|
||
features. Thus, if you are looking for a stable production system that
|
||
respects your freedom as a computer user, a good solution at this point
|
||
is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
|
||
more established GNU/Linux distributions}. We hope you can soon switch
|
||
to the GNU system without fear, of course. In the meantime, you can
|
||
also keep using your distribution and try out the package manager on top
|
||
of it (@pxref{Installation}).
|
||
|
||
Before you proceed with the installation, be aware of the following
|
||
noteworthy limitations applicable to version @value{VERSION}:
|
||
|
||
@itemize
|
||
@item
|
||
The installation process does not include a graphical user interface and
|
||
requires familiarity with GNU/Linux (see the following subsections to
|
||
get a feel of what that means.)
|
||
|
||
@item
|
||
The system does not yet provide graphical desktop environments such as
|
||
GNOME and KDE.
|
||
|
||
@item
|
||
Support for encrypted disks, the Logical Volume Manager (LVM), and swap
|
||
devices is missing.
|
||
|
||
@item
|
||
Few system services are currently supported out-of-the-box
|
||
(@pxref{Services}).
|
||
|
||
@item
|
||
On the order of 1,000 packages are available, which means that you may
|
||
occasionally find that a useful package is missing.
|
||
@end itemize
|
||
|
||
You've been warned. But more than a disclaimer, this is an invitation
|
||
to report issues (and success stories!), and join us in improving it.
|
||
@xref{Contributing}, for more info.
|
||
|
||
@subsection USB Stick Installation
|
||
|
||
An installation image for USB sticks can be downloaded from
|
||
@url{ftp://alpha.gnu.org/gnu/guix/gnu-usb-install-@value{VERSION}.@var{system}.xz},
|
||
where @var{system} is one of:
|
||
|
||
@table @code
|
||
@item x86_64-linux
|
||
for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
|
||
|
||
@item i686-linux
|
||
for a 32-bit GNU/Linux system on Intel-compatible CPUs.
|
||
@end table
|
||
|
||
This image contains a single partition with the tools necessary for an
|
||
installation. It is meant to be copied @emph{as is} to a large-enough
|
||
USB stick.
|
||
|
||
To copy the image to a USB stick, follow these steps:
|
||
|
||
@enumerate
|
||
@item
|
||
Decompress the image using the @command{xz} command:
|
||
|
||
@example
|
||
xz -d gnu-usb-install-@value{VERSION}.@var{system}.xz
|
||
@end example
|
||
|
||
@item
|
||
Insert a USB stick of 1@tie{}GiB or more in your machine, and determine
|
||
its device name. Assuming that USB stick is known as @file{/dev/sdX},
|
||
copy the image with:
|
||
|
||
@example
|
||
dd if=gnu-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
|
||
@end example
|
||
|
||
Access to @file{/dev/sdX} usually requires root privileges.
|
||
@end enumerate
|
||
|
||
Once this is done, you should be able to reboot the system and boot from
|
||
the USB stick. The latter usually requires you to get in the BIOS' boot
|
||
menu, where you can choose to boot from the USB stick.
|
||
|
||
@subsection Preparing for Installation
|
||
|
||
Once you have successfully booted the image on the USB stick, you should
|
||
end up with a root prompt. Several console TTYs are configured and can
|
||
be used to run commands as root. TTY2 shows this documentation,
|
||
browsable using the Info reader commands (@pxref{Help,,, info, Info: An
|
||
Introduction}).
|
||
|
||
To install the system, you would:
|
||
|
||
@enumerate
|
||
|
||
@item
|
||
Configure the network, by running @command{dhclient eth0} (to get an
|
||
automatically assigned IP address from the wired network interface
|
||
controller), or using the @command{ifconfig} command.
|
||
|
||
The system automatically loads drivers for your network interface
|
||
controllers.
|
||
|
||
Setting up network access is almost always a requirement because the
|
||
image does not contain all the software and tools that may be needed.
|
||
|
||
@item
|
||
Unless this has already been done, you must partition and format the
|
||
target partitions.
|
||
|
||
Preferably, assign partitions a label so that you can easily and
|
||
reliably refer to them in @code{file-system} declarations (@pxref{File
|
||
Systems}). This is typically done using the @code{-L} option of
|
||
@command{mkfs.ext4} and related commands.
|
||
|
||
The installation image includes Parted (@pxref{Overview,,, parted, GNU
|
||
Parted User Manual}), @command{fdisk}, and e2fsprogs, the suite of tools
|
||
to manipulate ext2/ext3/ext4 file systems.
|
||
|
||
@item
|
||
Once that is done, mount the target root partition under @file{/mnt}.
|
||
|
||
@item
|
||
Lastly, run @code{deco start cow-store /mnt}.
|
||
|
||
This will make @file{/gnu/store} copy-on-write, such that packages added
|
||
to it during the installation phase will be written to the target disk
|
||
rather than kept in memory.
|
||
|
||
@end enumerate
|
||
|
||
|
||
@subsection Proceeding with the Installation
|
||
|
||
With the target partitions ready, you now have to edit a file and
|
||
provide the declaration of the operating system to be installed. To
|
||
that end, the installation system comes with two text editors: GNU nano
|
||
(@pxref{Top,,, nano, GNU nano Manual}), and GNU Zile, an Emacs clone.
|
||
It is better to store that file on the target root file system, say, as
|
||
@file{/mnt/etc/config.scm}.
|
||
|
||
A minimal operating system configuration, with just the bare minimum and
|
||
only a root account would look like this (on the installation system,
|
||
this example is available as @file{/etc/configuration-template.scm}):
|
||
|
||
@example
|
||
@include os-config.texi
|
||
@end example
|
||
|
||
@noindent
|
||
For more information on @code{operating-system} declarations,
|
||
@pxref{Using the Configuration System}.
|
||
|
||
Once that is done, the new system must be initialized (remember that the
|
||
target root file system is mounted under @file{/mnt}):
|
||
|
||
@example
|
||
guix system init /mnt/etc/config.scm /mnt
|
||
@end example
|
||
|
||
@noindent
|
||
This will copy all the necessary files, and install GRUB on
|
||
@file{/dev/sdX}, unless you pass the @option{--no-grub} option. For
|
||
more information, @pxref{Invoking guix system}. This command may trigger
|
||
downloads or builds of missing packages, which can take some time.
|
||
|
||
Once that command has completed---and hopefully succeeded!---you can
|
||
run @command{reboot} and boot into the new system. Cross fingers, and
|
||
join us on @code{#guix} on the Freenode IRC network or on
|
||
@file{guix-devel@@gnu.org} to share your experience---good or not so
|
||
good.
|
||
|
||
@subsection Building the Installation Image
|
||
|
||
The installation image described above was built using the @command{guix
|
||
system} command, specifically:
|
||
|
||
@example
|
||
guix system disk-image --image-size=800MiB gnu/system/install.scm
|
||
@end example
|
||
|
||
@xref{Invoking guix system}, for more information. See
|
||
@file{gnu/system/install.scm} in the source tree for more information
|
||
about the installation image.
|
||
|
||
@node System Configuration
|
||
@section System Configuration
|
||
|
||
@cindex system configuration
|
||
The GNU system supports a consistent whole-system configuration
|
||
mechanism. By that we mean that all aspects of the global system
|
||
configuration---such as the available system services, timezone and
|
||
locale settings, user accounts---are declared in a single place. Such
|
||
a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
|
||
|
||
One of the advantages of putting all the system configuration under the
|
||
control of Guix is that it supports transactional system upgrades, and
|
||
makes it possible to roll-back to a previous system instantiation,
|
||
should something go wrong with the new one (@pxref{Features}). Another
|
||
one is that it makes it easy to replicate the exact same configuration
|
||
across different machines, or at different points in time, without
|
||
having to resort to additional administration tools layered on top of
|
||
the system's own tools.
|
||
@c Yes, we're talking of Puppet, Chef, & co. here. ↑
|
||
|
||
This section describes this mechanism. First we focus on the system
|
||
administrator's viewpoint---explaining how the system is configured and
|
||
instantiated. Then we show how this mechanism can be extended, for
|
||
instance to support new system services.
|
||
|
||
@menu
|
||
* Using the Configuration System:: Customizing your GNU system.
|
||
* File Systems:: Configuring file system mounts.
|
||
* User Accounts:: Specifying user accounts.
|
||
* Services:: Specifying system services.
|
||
* Setuid Programs:: Programs running with root privileges.
|
||
* Initial RAM Disk:: Linux-Libre bootstrapping.
|
||
* Invoking guix system:: Instantiating a system configuration.
|
||
* Defining Services:: Adding new service definitions.
|
||
@end menu
|
||
|
||
@node Using the Configuration System
|
||
@subsection Using the Configuration System
|
||
|
||
The operating system is configured by providing an
|
||
@code{operating-system} declaration in a file that can then be passed to
|
||
the @command{guix system} command (@pxref{Invoking guix system}). A
|
||
simple setup, with the default system services, the default Linux-Libre
|
||
kernel, initial RAM disk, and boot loader looks like this:
|
||
|
||
@findex operating-system
|
||
@lisp
|
||
(use-modules (gnu) ; for 'user-account', '%base-services', etc.
|
||
(gnu packages emacs) ; for 'emacs'
|
||
(gnu services ssh)) ; for 'lsh-service'
|
||
|
||
(operating-system
|
||
(host-name "komputilo")
|
||
(timezone "Europe/Paris")
|
||
(locale "fr_FR.UTF-8")
|
||
(bootloader (grub-configuration
|
||
(device "/dev/sda")))
|
||
(file-systems (cons (file-system
|
||
(device "/dev/sda1") ; or partition label
|
||
(mount-point "/")
|
||
(type "ext3"))
|
||
%base-file-systems))
|
||
(users (list (user-account
|
||
(name "alice")
|
||
(password "")
|
||
(uid 1000) (group 100)
|
||
(comment "Bob's sister")
|
||
(home-directory "/home/alice"))))
|
||
(packages (cons emacs %base-packages))
|
||
(services (cons (lsh-service #:port 2222 #:allow-root-login? #t)
|
||
%base-services)))
|
||
@end lisp
|
||
|
||
This example should be self-describing. Some of the fields defined
|
||
above, such as @code{host-name} and @code{bootloader}, are mandatory.
|
||
Others, such as @code{packages} and @code{services}, can be omitted, in
|
||
which case they get a default value.
|
||
|
||
@vindex %base-packages
|
||
The @code{packages} field lists
|
||
packages that will be globally visible on the system, for all user
|
||
accounts---i.e., in every user's @code{PATH} environment variable---in
|
||
addition to the per-user profiles (@pxref{Invoking guix package}). The
|
||
@var{%base-packages} variable provides all the tools one would expect
|
||
for basic user and administrator tasks---including the GNU Core
|
||
Utilities, the GNU Networking Utilities, the GNU Zile lightweight text
|
||
editor, @command{find}, @command{grep}, etc. The example above adds
|
||
Emacs to those, taken from the @code{(gnu packages emacs)} module
|
||
(@pxref{Package Modules}).
|
||
|
||
@vindex %base-services
|
||
The @code{services} field lists @dfn{system services} to be made
|
||
available when the system starts (@pxref{Services}).
|
||
The @code{operating-system} declaration above specifies that, in
|
||
addition to the basic services, we want the @command{lshd} secure shell
|
||
daemon listening on port 2222, and allowing remote @code{root} logins
|
||
(@pxref{Invoking lshd,,, lsh, GNU lsh Manual}). Under the hood,
|
||
@code{lsh-service} arranges so that @code{lshd} is started with the
|
||
right command-line options, possibly with supporting configuration files
|
||
generated as needed (@pxref{Defining Services}).
|
||
|
||
Assuming the above snippet is stored in the @file{my-system-config.scm}
|
||
file, the @command{guix system reconfigure my-system-config.scm} command
|
||
instantiates that configuration, and makes it the default GRUB boot
|
||
entry (@pxref{Invoking guix system}). The normal way to change the
|
||
system's configuration is by updating this file and re-running the
|
||
@command{guix system} command.
|
||
|
||
At the Scheme level, the bulk of an @code{operating-system} declaration
|
||
is instantiated with the following monadic procedure (@pxref{The Store
|
||
Monad}):
|
||
|
||
@deffn {Monadic Procedure} operating-system-derivation os
|
||
Return a derivation that builds @var{os}, an @code{operating-system}
|
||
object (@pxref{Derivations}).
|
||
|
||
The output of the derivation is a single directory that refers to all
|
||
the packages, configuration files, and other supporting files needed to
|
||
instantiate @var{os}.
|
||
@end deffn
|
||
|
||
@node File Systems
|
||
@subsection File Systems
|
||
|
||
The list of file systems to be mounted is specified in the
|
||
@code{file-systems} field of the operating system's declaration
|
||
(@pxref{Using the Configuration System}). Each file system is declared
|
||
using the @code{file-system} form, like this:
|
||
|
||
@example
|
||
(file-system
|
||
(mount-point "/home")
|
||
(device "/dev/sda3")
|
||
(type "ext4"))
|
||
@end example
|
||
|
||
As usual, some of the fields are mandatory---those shown in the example
|
||
above---while others can be omitted. These are described below.
|
||
|
||
@deftp {Data Type} file-system
|
||
Objects of this type represent file systems to be mounted. They
|
||
contain the following members:
|
||
|
||
@table @asis
|
||
@item @code{type}
|
||
This is a string specifying the type of the file system---e.g.,
|
||
@code{"ext4"}.
|
||
|
||
@item @code{mount-point}
|
||
This designates the place where the file system is to be mounted.
|
||
|
||
@item @code{device}
|
||
This names the ``source'' of the file system. By default it is the name
|
||
of a node under @file{/dev}, but its meaning depends on the @code{title}
|
||
field described below.
|
||
|
||
@item @code{title} (default: @code{'device})
|
||
This is a symbol that specifies how the @code{device} field is to be
|
||
interpreted.
|
||
|
||
When it is the symbol @code{device}, then the @code{device} field is
|
||
interpreted as a file name; when it is @code{label}, then @code{device}
|
||
is interpreted as a partition label name; when it is @code{uuid},
|
||
@code{device} is interpreted as a partition unique identifier (UUID).
|
||
|
||
The @code{label} and @code{uuid} options offer a way to refer to disk
|
||
partitions without having to hard-code their actual device name.
|
||
|
||
@item @code{flags} (default: @code{'()})
|
||
This is a list of symbols denoting mount flags. Recognized flags
|
||
include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
|
||
access to special files), @code{no-suid} (ignore setuid and setgid
|
||
bits), and @code{no-exec} (disallow program execution.)
|
||
|
||
@item @code{options} (default: @code{#f})
|
||
This is either @code{#f}, or a string denoting mount options.
|
||
|
||
@item @code{needed-for-boot?} (default: @code{#f})
|
||
This Boolean value indicates whether the file system is needed when
|
||
booting. If that is true, then the file system is mounted when the
|
||
initial RAM disk (initrd) is loaded. This is always the case, for
|
||
instance, for the root file system.
|
||
|
||
@item @code{check?} (default: @code{#t})
|
||
This Boolean indicates whether the file system needs to be checked for
|
||
errors before being mounted.
|
||
|
||
@item @code{create-mount-point?} (default: @code{#f})
|
||
When true, the mount point is created if it does not exist yet.
|
||
|
||
@end table
|
||
@end deftp
|
||
|
||
The @code{(gnu system file-systems)} exports the following useful
|
||
variables.
|
||
|
||
@defvr {Scheme Variable} %base-file-systems
|
||
These are essential file systems that are required on normal systems,
|
||
such as @var{%devtmpfs-file-system} (see below.) Operating system
|
||
declarations should always contain at least these.
|
||
@end defvr
|
||
|
||
@defvr {Scheme Variable} %devtmpfs-file-system
|
||
The @code{devtmpfs} file system to be mounted on @file{/dev}. This is a
|
||
requirement for udev (@pxref{Base Services, @code{udev-service}}).
|
||
@end defvr
|
||
|
||
@defvr {Scheme Variable} %pseudo-terminal-file-system
|
||
This is the file system to be mounted as @file{/dev/pts}. It supports
|
||
@dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
|
||
functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
|
||
Manual}). Pseudo-terminals are used by terminal emulators such as
|
||
@command{xterm}.
|
||
@end defvr
|
||
|
||
@defvr {Scheme Variable} %shared-memory-file-system
|
||
This file system is mounted as @file{/dev/shm} and is used to support
|
||
memory sharing across processes (@pxref{Memory-mapped I/O,
|
||
@code{shm_open},, libc, The GNU C Library Reference Manual}).
|
||
@end defvr
|
||
|
||
@defvr {Scheme Variable} %binary-format-file-system
|
||
The @code{binfmt_misc} file system, which allows handling of arbitrary
|
||
executable file types to be delegated to user space. This requires the
|
||
@code{binfmt.ko} kernel module to be loaded.
|
||
@end defvr
|
||
|
||
@defvr {Scheme Variable} %fuse-control-file-system
|
||
The @code{fusectl} file system, which allows unprivileged users to mount
|
||
and unmount user-space FUSE file systems. This requires the
|
||
@code{fuse.ko} kernel module to be loaded.
|
||
@end defvr
|
||
|
||
@node User Accounts
|
||
@subsection User Accounts
|
||
|
||
User accounts are specified with the @code{user-account} form:
|
||
|
||
@example
|
||
(user-account
|
||
(name "alice")
|
||
(group "users")
|
||
(supplementary-groups '("wheel")) ; allow use of sudo, etc.
|
||
(comment "Bob's sister")
|
||
(home-directory "/home/alice"))
|
||
@end example
|
||
|
||
@deftp {Data Type} user-account
|
||
Objects of this type represent user accounts. The following members may
|
||
be specified:
|
||
|
||
@table @asis
|
||
@item @code{name}
|
||
The name of the user account.
|
||
|
||
@item @code{group}
|
||
This is the name (a string) or identifier (a number) of the user group
|
||
this account belongs to.
|
||
|
||
@item @code{supplementary-groups} (default: @code{'()})
|
||
Optionally, this can be defined as a list of group names that this
|
||
account belongs to.
|
||
|
||
@item @code{uid} (default: @code{#f})
|
||
This is the user ID for this account (a number), or @code{#f}. In the
|
||
latter case, a number is automatically chosen by the system when the
|
||
account is created.
|
||
|
||
@item @code{comment} (default: @code{""})
|
||
A comment about the account, such as the account's owner full name.
|
||
|
||
@item @code{home-directory}
|
||
This is the name of the home directory for the account.
|
||
|
||
@item @code{shell} (default: Bash)
|
||
This is a G-expression denoting the file name of a program to be used as
|
||
the shell (@pxref{G-Expressions}).
|
||
|
||
@item @code{system?} (default: @code{#f})
|
||
This Boolean value indicates whether the account is a ``system''
|
||
account. System accounts are sometimes treated specially; for instance,
|
||
graphical login managers do not list them.
|
||
|
||
@item @code{password} (default: @code{#f})
|
||
Unless @code{#f}, this is the password to be used for the account.
|
||
|
||
@end table
|
||
@end deftp
|
||
|
||
User group declarations are even simpler:
|
||
|
||
@example
|
||
(user-group (name "students"))
|
||
@end example
|
||
|
||
@deftp {Data Type} user-group
|
||
This type is for, well, user groups. There are just a few fields:
|
||
|
||
@table @asis
|
||
@item @code{name}
|
||
The group's name.
|
||
|
||
@item @code{id} (default: @code{#f})
|
||
The group identifier (a number). If @code{#f}, a new number is
|
||
automatically allocated when the group is created.
|
||
|
||
@item @code{system?} (default: @code{#f})
|
||
This Boolean value indicates whether the group is a ``system'' group.
|
||
System groups have low numerical IDs.
|
||
|
||
@item @code{password} (default: @code{#f})
|
||
What, user groups can have a password? Well, apparently yes. Unless
|
||
@code{#f}, this field specifies the group's password.
|
||
|
||
@end table
|
||
@end deftp
|
||
|
||
For convenience, a variable lists all the basic user groups one may
|
||
expect:
|
||
|
||
@defvr {Scheme Variable} %base-groups
|
||
This is the list of basic user groups that users and/or packages expect
|
||
to be present on the system. This includes groups such as ``root'',
|
||
``wheel'', and ``users'', as well as groups used to control access to
|
||
specific devices such as ``audio'', ``disk'', and ``cdrom''.
|
||
@end defvr
|
||
|
||
|
||
@node Services
|
||
@subsection Services
|
||
|
||
@cindex system services
|
||
An important part of preparing an @code{operating-system} declaration is
|
||
listing @dfn{system services} and their configuration (@pxref{Using the
|
||
Configuration System}). System services are typically daemons launched
|
||
when the system boots, or other actions needed at that time---e.g.,
|
||
configuring network access. They are managed by GNU@tie{}dmd
|
||
(@pxref{Introduction,,, dmd, GNU dmd Manual}).
|
||
|
||
The following sections document the available services, starting with
|
||
the core services.
|
||
|
||
@menu
|
||
* Base Services:: Essential system services.
|
||
* Networking Services:: Network setup, SSH daemon, etc.
|
||
* X Window:: Graphical display.
|
||
@end menu
|
||
|
||
@node Base Services
|
||
@subsubsection Base Services
|
||
|
||
The @code{(gnu services base)} module provides definitions for the basic
|
||
services that one expects from the system. The services exported by
|
||
this module are listed below.
|
||
|
||
@defvr {Scheme Variable} %base-services
|
||
This variable contains a list of basic services@footnote{Technically,
|
||
this is a list of monadic services. @xref{The Store Monad}.} one would
|
||
expect from the system: a login service (mingetty) on each tty, syslogd,
|
||
libc's name service cache daemon (nscd), the udev device manager, and
|
||
more.
|
||
|
||
This is the default value of the @code{services} field of
|
||
@code{operating-system} declarations. Usually, when customizing a
|
||
system, you will want to append services to @var{%base-services}, like
|
||
this:
|
||
|
||
@example
|
||
(cons* (avahi-service) (lshd-service) %base-services)
|
||
@end example
|
||
@end defvr
|
||
|
||
@deffn {Monadic Procedure} host-name-service @var{name}
|
||
Return a service that sets the host name to @var{name}.
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} mingetty-service @var{tty} [#:motd] @
|
||
[#:auto-login #f] [#:login-program] [#:login-pause? #f] @
|
||
[#:allow-empty-passwords? #f]
|
||
Return a service to run mingetty on @var{tty}.
|
||
|
||
When @var{allow-empty-passwords?} is true, allow empty log-in password. When
|
||
@var{auto-login} is true, it must be a user name under which to log-in
|
||
automatically. @var{login-pause?} can be set to @code{#t} in conjunction with
|
||
@var{auto-login}, in which case the user will have to press a key before the
|
||
login shell is launched.
|
||
|
||
When true, @var{login-program} is a gexp or a monadic gexp denoting the name
|
||
of the log-in program (the default is the @code{login} program from the Shadow
|
||
tool suite.)
|
||
|
||
@var{motd} is a monadic value containing a text file to use as
|
||
the ``message of the day''.
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} nscd-service [#:glibc glibc]
|
||
Return a service that runs libc's name service cache daemon (nscd).
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} syslog-service
|
||
Return a service that runs @code{syslogd} with reasonable default
|
||
settings.
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} guix-service [#:guix guix] @
|
||
[#:builder-group "guixbuild"] [#:build-accounts 10] @
|
||
[#:authorize-hydra-key? #f] [#:use-substitutes? #t] @
|
||
[#:extra-options '()]
|
||
Return a service that runs the build daemon from @var{guix}, and has
|
||
@var{build-accounts} user accounts available under @var{builder-group}.
|
||
|
||
When @var{authorize-hydra-key?} is true, the @code{hydra.gnu.org} public key
|
||
provided by @var{guix} is authorized upon activation, meaning that substitutes
|
||
from @code{hydra.gnu.org} are used by default.
|
||
|
||
If @var{use-substitutes?} is false, the daemon is run with
|
||
@option{--no-substitutes} (@pxref{Invoking guix-daemon,
|
||
@option{--no-substitutes}}).
|
||
|
||
Finally, @var{extra-options} is a list of additional command-line options
|
||
passed to @command{guix-daemon}.
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} udev-service [#:udev udev]
|
||
Run @var{udev}, which populates the @file{/dev} directory dynamically.
|
||
@end deffn
|
||
|
||
|
||
@node Networking Services
|
||
@subsubsection Networking Services
|
||
|
||
The @code{(gnu system networking)} module provides services to configure
|
||
the network interface.
|
||
|
||
@deffn {Monadic Procedure} static-networking-service @var{interface} @var{ip} @
|
||
[#:gateway #f] [#:name-services @code{'()}]
|
||
Return a service that starts @var{interface} with address @var{ip}. If
|
||
@var{gateway} is true, it must be a string specifying the default network
|
||
gateway.
|
||
@end deffn
|
||
|
||
@deffn {Monadic Procedure} tor-service [#:tor tor]
|
||
Return a service to run the @uref{https://torproject.org,Tor} daemon.
|
||
|
||
The daemon runs with the default settings (in particular the default exit
|
||
policy) as the @code{tor} unprivileged user.
|
||
@end deffn
|
||
|
||
In addition, @code{(gnu system ssh)} provides the following service.
|
||
|
||
@deffn {Monadic Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
|
||
[#:interfaces '()] [#:port-number 22] @
|
||
[#:allow-empty-passwords? #f] [#:root-login? #f] @
|
||
[#:syslog-output? #t] [#:x11-forwarding? #t] @
|
||
[#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
|
||
[public-key-authentication? #t] [#:initialize? #f]
|
||
Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
|
||
@var{host-key} must designate a file containing the host key, and readable
|
||
only by root.
|
||
|
||
When @var{initialize?} is true, automatically create the seed and host key
|
||
upon service activation if they do not exist yet. This may take long and
|
||
require interaction.
|
||
|
||
When @var{interfaces} is empty, lshd listens for connections on all the
|
||
network interfaces; otherwise, @var{interfaces} must be a list of host names
|
||
or addresses.
|
||
|
||
@var{allow-empty-passwords?} specifies whether to accepts log-ins with empty
|
||
passwords, and @var{root-login?} specifies whether to accepts log-ins as
|
||
root.
|
||
|
||
The other options should be self-descriptive.
|
||
@end deffn
|
||
|
||
@node X Window
|
||
@subsubsection X Window
|
||
|
||
Support for the X Window graphical display system---specifically
|
||
Xorg---is provided by the @code{(gnu services xorg)} module. Note that
|
||
there is no @code{xorg-service} procedure. Instead, the X server is
|
||
started by the @dfn{login manager}, currently SLiM.
|
||
|
||
@deffn {Monadic Procedure} slim-service [#:allow-empty-passwords? #f] @
|
||
[#:auto-login? #f] [#:default-user ""] [#:startx]
|
||
Return a service that spawns the SLiM graphical login manager, which in
|
||
turn starts the X display server with @var{startx}, a command as returned by
|
||
@code{xorg-start-command}.
|
||
|
||
When @var{allow-empty-passwords?} is true, allow logins with an empty
|
||
password. When @var{auto-login?} is true, log in automatically as
|
||
@var{default-user}.
|
||
@end deffn
|
||
|
||
|
||
@node Setuid Programs
|
||
@subsection Setuid Programs
|
||
|
||
@cindex setuid programs
|
||
Some programs need to run with ``root'' privileges, even when they are
|
||
launched by unprivileged users. A notorious example is the
|
||
@command{passwd} programs, which can users can run to change their
|
||
password, and which requires write access to the @file{/etc/passwd} and
|
||
@file{/etc/shadow} files---something normally restricted to root, for
|
||
obvious security reasons. To address that, these executables are
|
||
@dfn{setuid-root}, meaning that they always run with root privileges
|
||
(@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
|
||
for more info about the setuid mechanisms.)
|
||
|
||
The store itself @emph{cannot} contain setuid programs: that would be a
|
||
security issue since any user on the system can write derivations that
|
||
populate the store (@pxref{The Store}). Thus, a different mechanism is
|
||
used: instead of changing the setuid bit directly on files that are in
|
||
the store, we let the system administrator @emph{declare} which programs
|
||
should be setuid root.
|
||
|
||
The @code{setuid-programs} field of an @code{operating-system}
|
||
declaration contains a list of G-expressions denoting the names of
|
||
programs to be setuid-root (@pxref{Using the Configuration System}).
|
||
For instance, the @command{passwd} program, which is part of the Shadow
|
||
package, can be designated by this G-expression (@pxref{G-Expressions}):
|
||
|
||
@example
|
||
#~(string-append #$shadow "/bin/passwd")
|
||
@end example
|
||
|
||
A default set of setuid programs is defined by the
|
||
@code{%setuid-programs} variable of the @code{(gnu system)} module.
|
||
|
||
@defvr {Scheme Variable} %setuid-programs
|
||
A list of G-expressions denoting common programs that are setuid-root.
|
||
|
||
The list includes commands such as @command{passwd}, @command{ping},
|
||
@command{su}, and @command{sudo}.
|
||
@end defvr
|
||
|
||
Under the hood, the actual setuid programs are created in the
|
||
@file{/run/setuid-programs} directory at system activation time. The
|
||
files in this directory refer to the ``real'' binaries, which are in the
|
||
store.
|
||
|
||
|
||
@node Initial RAM Disk
|
||
@subsection Initial RAM Disk
|
||
|
||
@cindex initial RAM disk (initrd)
|
||
@cindex initrd (initial RAM disk)
|
||
For bootstrapping purposes, the Linux-Libre kernel is passed an
|
||
@dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
|
||
root file system, as well as an initialization script. The latter is
|
||
responsible for mounting the real root file system, and for loading any
|
||
kernel modules that may be needed to achieve that.
|
||
|
||
The @code{initrd} field of an @code{operating-system} declaration allows
|
||
you to specify which initrd you would like to use. The @code{(gnu
|
||
system linux-initrd)} module provides two ways to build an initrd: the
|
||
high-level @code{base-initrd} procedure, and the low-level
|
||
@code{expression->initrd} procedure.
|
||
|
||
The @code{base-initrd} procedure is intended to cover most common uses.
|
||
For example, if you want to add a bunch of kernel modules to be loaded
|
||
at boot time, you can define the @code{initrd} field of the operating
|
||
system declaration like this:
|
||
|
||
@example
|
||
(initrd (cut base-initrd <>
|
||
#:extra-modules '("my.ko" "modules.ko")))
|
||
@end example
|
||
|
||
@noindent
|
||
Note that for the example above, the SRFI-26 module needs to be imported
|
||
(@pxref{SRFI-26,,, guile, GNU Guile Reference Manual}).
|
||
|
||
It also handles common use cases that involves using the system as a
|
||
QEMU guest, or as a ``live'' system whose root file system is volatile.
|
||
|
||
@deffn {Monadic Procedure} base-initrd @var{file-systems} @
|
||
[#:qemu-networking? #f] [#:virtio? #f] [#:volatile-root? #f] @
|
||
[#:extra-modules '()]
|
||
Return a monadic derivation that builds a generic initrd. @var{file-systems} is
|
||
a list of file-systems to be mounted by the initrd, possibly in addition to
|
||
the root file system specified on the kernel command line via @code{--root}.
|
||
|
||
When @var{qemu-networking?} is true, set up networking with the standard QEMU
|
||
parameters. When @var{virtio?} is true, load additional modules so the initrd can
|
||
be used as a QEMU guest with para-virtualized I/O drivers.
|
||
|
||
When @var{volatile-root?} is true, the root file system is writable but any changes
|
||
to it are lost.
|
||
|
||
The initrd is automatically populated with all the kernel modules necessary
|
||
for @var{file-systems} and for the given options. However, additional kernel
|
||
modules can be listed in @var{extra-modules}. They will be added to the initrd, and
|
||
loaded at boot time in the order in which they appear.
|
||
@end deffn
|
||
|
||
Needless to say, the initrds we produce and use embed a
|
||
statically-linked Guile, and the initialization program is a Guile
|
||
program. That gives a lot of flexibility. The
|
||
@code{expression->initrd} procedure builds such an initrd, given the
|
||
program to run in that initrd.
|
||
|
||
@deffn {Monadic Procedure} expression->initrd @var{exp} @
|
||
[#:guile %guile-static-stripped] [#:name "guile-initrd"] @
|
||
[#:modules '()] [#:to-copy '()] [#:linux #f] @
|
||
[#:linux-modules '()]
|
||
Return a derivation that builds a Linux initrd (a gzipped cpio archive)
|
||
containing @var{guile} and that evaluates @var{exp}, a G-expression,
|
||
upon booting.
|
||
|
||
@var{linux-modules} is a list of @file{.ko} file names to be copied from
|
||
@var{linux} into the initrd. @var{to-copy} is a list of additional
|
||
derivations or packages to copy to the initrd. @var{modules} is a list
|
||
of Guile module names to be embedded in the initrd.
|
||
@end deffn
|
||
|
||
@node Invoking guix system
|
||
@subsection Invoking @code{guix system}
|
||
|
||
Once you have written an operating system declaration, as seen in the
|
||
previous section, it can be @dfn{instantiated} using the @command{guix
|
||
system} command. The synopsis is:
|
||
|
||
@example
|
||
guix system @var{options}@dots{} @var{action} @var{file}
|
||
@end example
|
||
|
||
@var{file} must be the name of a file containing an
|
||
@code{operating-system} declaration. @var{action} specifies how the
|
||
operating system is instantiate. Currently the following values are
|
||
supported:
|
||
|
||
@table @code
|
||
@item reconfigure
|
||
Build the operating system described in @var{file}, activate it, and
|
||
switch to it@footnote{This action is usable only on systems already
|
||
running GNU.}.
|
||
|
||
This effects all the configuration specified in @var{file}: user
|
||
accounts, system services, global package list, setuid programs, etc.
|
||
|
||
It also adds a GRUB menu entry for the new OS configuration, and moves
|
||
entries for older configurations to a submenu---unless
|
||
@option{--no-grub} is passed.
|
||
|
||
@item build
|
||
Build the operating system's derivation, which includes all the
|
||
configuration files and programs needed to boot and run the system.
|
||
This action does not actually install anything.
|
||
|
||
@item init
|
||
Populate the given directory with all the files necessary to run the
|
||
operating system specified in @var{file}. This is useful for first-time
|
||
installations of the GNU system. For instance:
|
||
|
||
@example
|
||
guix system init my-os-config.scm /mnt
|
||
@end example
|
||
|
||
copies to @file{/mnt} all the store items required by the configuration
|
||
specified in @file{my-os-config.scm}. This includes configuration
|
||
files, packages, and so on. It also creates other essential files
|
||
needed for the system to operate correctly---e.g., the @file{/etc},
|
||
@file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
|
||
|
||
This command also installs GRUB on the device specified in
|
||
@file{my-os-config}, unless the @option{--no-grub} option was passed.
|
||
|
||
@item vm
|
||
@cindex virtual machine
|
||
Build a virtual machine that contain the operating system declared in
|
||
@var{file}, and return a script to run that virtual machine (VM).
|
||
|
||
The VM shares its store with the host system.
|
||
|
||
@item vm-image
|
||
@itemx disk-image
|
||
Return a virtual machine or disk image of the operating system declared
|
||
in @var{file} that stands alone. Use the @option{--image-size} option
|
||
to specify the size of the image.
|
||
|
||
When using @code{vm-image}, the returned image is in qcow2 format, which
|
||
the QEMU emulator can efficiently use.
|
||
|
||
When using @code{disk-image}, a raw disk image is produced; it can be
|
||
copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
|
||
the device corresponding to a USB stick, one can copy the image on it
|
||
using the following command:
|
||
|
||
@example
|
||
# dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
|
||
@end example
|
||
|
||
@end table
|
||
|
||
@var{options} can contain any of the common build options provided by
|
||
@command{guix build} (@pxref{Invoking guix build}). In addition,
|
||
@var{options} can contain one of the following:
|
||
|
||
@table @option
|
||
@item --system=@var{system}
|
||
@itemx -s @var{system}
|
||
Attempt to build for @var{system} instead of the host's system type.
|
||
This works as per @command{guix build} (@pxref{Invoking guix build}).
|
||
|
||
@item --image-size=@var{size}
|
||
For the @code{vm-image} and @code{disk-image} actions, create an image
|
||
of the given @var{size}. @var{size} may be a number of bytes, or it may
|
||
include a unit as a suffix, such as @code{MiB} for mebibytes and
|
||
@code{GB} for gigabytes.
|
||
@end table
|
||
|
||
Note that all the actions above, except @code{build} and @code{init},
|
||
rely on KVM support in the Linux-Libre kernel. Specifically, the
|
||
machine should have hardware virtualization support, the corresponding
|
||
KVM kernel module should be loaded, and the @file{/dev/kvm} device node
|
||
must exist and be readable and writable by the user and by the daemon's
|
||
build users.
|
||
|
||
@node Defining Services
|
||
@subsection Defining Services
|
||
|
||
The @code{(gnu services @dots{})} modules define several procedures that allow
|
||
users to declare the operating system's services (@pxref{Using the
|
||
Configuration System}). These procedures are @emph{monadic
|
||
procedures}---i.e., procedures that return a monadic value in the store
|
||
monad (@pxref{The Store Monad}). For examples of such procedures,
|
||
@xref{Services}.
|
||
|
||
@cindex service definition
|
||
The monadic value returned by those procedures is a @dfn{service
|
||
definition}---a structure as returned by the @code{service} form.
|
||
Service definitions specifies the inputs the service depends on, and an
|
||
expression to start and stop the service. Behind the scenes, service
|
||
definitions are ``translated'' into the form suitable for the
|
||
configuration file of dmd, the init system (@pxref{Services,,, dmd, GNU
|
||
dmd Manual}).
|
||
|
||
As an example, here is what the @code{nscd-service} procedure looks
|
||
like:
|
||
|
||
@lisp
|
||
(define (nscd-service)
|
||
(with-monad %store-monad
|
||
(return (service
|
||
(documentation "Run libc's name service cache daemon.")
|
||
(provision '(nscd))
|
||
(activate #~(begin
|
||
(use-modules (guix build utils))
|
||
(mkdir-p "/var/run/nscd")))
|
||
(start #~(make-forkexec-constructor
|
||
(string-append #$glibc "/sbin/nscd")
|
||
"-f" "/dev/null" "--foreground"))
|
||
(stop #~(make-kill-destructor))
|
||
(respawn? #f)))))
|
||
@end lisp
|
||
|
||
@noindent
|
||
The @code{activate}, @code{start}, and @code{stop} fields are G-expressions
|
||
(@pxref{G-Expressions}). The @code{activate} field contains a script to
|
||
run at ``activation'' time; it makes sure that the @file{/var/run/nscd}
|
||
directory exists before @command{nscd} is started.
|
||
|
||
The @code{start} and @code{stop} fields refer to dmd's facilities to
|
||
start and stop processes (@pxref{Service De- and Constructors,,, dmd,
|
||
GNU dmd Manual}). The @code{provision} field specifies the name under
|
||
which this service is known to dmd, and @code{documentation} specifies
|
||
on-line documentation. Thus, the commands @command{deco start ncsd},
|
||
@command{deco stop nscd}, and @command{deco doc nscd} will do what you
|
||
would expect (@pxref{Invoking deco,,, dmd, GNU dmd Manual}).
|
||
|
||
|
||
@node Installing Debugging Files
|
||
@section Installing Debugging Files
|
||
|
||
@cindex debugging files
|
||
Program binaries, as produced by the GCC compilers for instance, are
|
||
typically written in the ELF format, with a section containing
|
||
@dfn{debugging information}. Debugging information is what allows the
|
||
debugger, GDB, to map binary code to source code; it is required to
|
||
debug a compiled program in good conditions.
|
||
|
||
The problem with debugging information is that is takes up a fair amount
|
||
of disk space. For example, debugging information for the GNU C Library
|
||
weighs in at more than 60 MiB. Thus, as a user, keeping all the
|
||
debugging info of all the installed programs is usually not an option.
|
||
Yet, space savings should not come at the cost of an impediment to
|
||
debugging---especially in the GNU system, which should make it easier
|
||
for users to exert their computing freedom (@pxref{GNU Distribution}).
|
||
|
||
Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
|
||
mechanism that allows users to get the best of both worlds: debugging
|
||
information can be stripped from the binaries and stored in separate
|
||
files. GDB is then able to load debugging information from those files,
|
||
when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
|
||
with GDB}).
|
||
|
||
The GNU distribution takes advantage of this by storing debugging
|
||
information in the @code{lib/debug} sub-directory of a separate package
|
||
output unimaginatively called @code{debug} (@pxref{Packages with
|
||
Multiple Outputs}). Users can choose to install the @code{debug} output
|
||
of a package when they need it. For instance, the following command
|
||
installs the debugging information for the GNU C Library and for GNU
|
||
Guile:
|
||
|
||
@example
|
||
guix package -i glibc:debug guile:debug
|
||
@end example
|
||
|
||
GDB must then be told to look for debug files in the user's profile, by
|
||
setting the @code{debug-file-directory} variable (consider setting it
|
||
from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
|
||
GDB}):
|
||
|
||
@example
|
||
(gdb) set debug-file-directory ~/.guix-profile/lib/debug
|
||
@end example
|
||
|
||
From there on, GDB will pick up debugging information from the
|
||
@code{.debug} files under @file{~/.guix-profile/lib/debug}.
|
||
|
||
In addition, you will most likely want GDB to be able to show the source
|
||
code being debugged. To do that, you will have to unpack the source
|
||
code of the package of interest (obtained with @code{guix build
|
||
--source}, @pxref{Invoking guix build}), and to point GDB to that source
|
||
directory using the @code{directory} command (@pxref{Source Path,
|
||
@code{directory},, gdb, Debugging with GDB}).
|
||
|
||
@c XXX: keep me up-to-date
|
||
The @code{debug} output mechanism in Guix is implemented by the
|
||
@code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
|
||
opt-in---debugging information is available only for those packages
|
||
whose definition explicitly declares a @code{debug} output. This may be
|
||
changed to opt-out in the future, if our build farm servers can handle
|
||
the load. To check whether a package has a @code{debug} output, use
|
||
@command{guix package --list-available} (@pxref{Invoking guix package}).
|
||
|
||
|
||
@node Package Modules
|
||
@section Package Modules
|
||
|
||
From a programming viewpoint, the package definitions of the
|
||
GNU distribution are provided by Guile modules in the @code{(gnu packages
|
||
@dots{})} name space@footnote{Note that packages under the @code{(gnu
|
||
packages @dots{})} module name space are not necessarily ``GNU
|
||
packages''. This module naming scheme follows the usual Guile module
|
||
naming convention: @code{gnu} means that these modules are distributed
|
||
as part of the GNU system, and @code{packages} identifies modules that
|
||
define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
|
||
Reference Manual}). For instance, the @code{(gnu packages emacs)}
|
||
module exports a variable named @code{emacs}, which is bound to a
|
||
@code{<package>} object (@pxref{Defining Packages}).
|
||
|
||
The @code{(gnu packages @dots{})} module name space is special: it is
|
||
automatically scanned for packages by the command-line tools. For
|
||
instance, when running @code{guix package -i emacs}, all the @code{(gnu
|
||
packages @dots{})} modules are scanned until one that exports a package
|
||
object whose name is @code{emacs} is found. This package search
|
||
facility is implemented in the @code{(gnu packages)} module.
|
||
|
||
Users can store package definitions in modules with different
|
||
names---e.g., @code{(my-packages emacs)}. In that case, commands such
|
||
as @command{guix package} and @command{guix build} have to be used with
|
||
the @code{-e} option so that they know where to find the package.
|
||
|
||
The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
|
||
each package is built based solely on other packages in the
|
||
distribution. The root of this dependency graph is a small set of
|
||
@dfn{bootstrap binaries}, provided by the @code{(gnu packages
|
||
bootstrap)} module. For more information on bootstrapping,
|
||
@ref{Bootstrapping}.
|
||
|
||
@node Packaging Guidelines
|
||
@section Packaging Guidelines
|
||
|
||
The GNU distribution is nascent and may well lack some of your favorite
|
||
packages. This section describes how you can help make the distribution
|
||
grow. @xref{Contributing}, for additional information on how you can
|
||
help.
|
||
|
||
Free software packages are usually distributed in the form of
|
||
@dfn{source code tarballs}---typically @file{tar.gz} files that contain
|
||
all the source files. Adding a package to the distribution means
|
||
essentially two things: adding a @dfn{recipe} that describes how to
|
||
build the package, including a list of other packages required to build
|
||
it, and adding @dfn{package meta-data} along with that recipe, such as a
|
||
description and licensing information.
|
||
|
||
In Guix all this information is embodied in @dfn{package definitions}.
|
||
Package definitions provide a high-level view of the package. They are
|
||
written using the syntax of the Scheme programming language; in fact,
|
||
for each package we define a variable bound to the package definition,
|
||
and export that variable from a module (@pxref{Package Modules}).
|
||
However, in-depth Scheme knowledge is @emph{not} a prerequisite for
|
||
creating packages. For more information on package definitions,
|
||
@ref{Defining Packages}.
|
||
|
||
Once a package definition is in place, stored in a file in the Guix
|
||
source tree, it can be tested using the @command{guix build} command
|
||
(@pxref{Invoking guix build}). For example, assuming the new package is
|
||
called @code{gnew}, you may run this command from the Guix build tree:
|
||
|
||
@example
|
||
./pre-inst-env guix build gnew --keep-failed
|
||
@end example
|
||
|
||
Using @code{--keep-failed} makes it easier to debug build failures since
|
||
it provides access to the failed build tree. Another useful
|
||
command-line option when debugging is @code{--log-file}, to access the
|
||
build log.
|
||
|
||
If the package is unknown to the @command{guix} command, it may be that
|
||
the source file contains a syntax error, or lacks a @code{define-public}
|
||
clause to export the package variable. To figure it out, you may load
|
||
the module from Guile to get more information about the actual error:
|
||
|
||
@example
|
||
./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
|
||
@end example
|
||
|
||
Once your package builds correctly, please send us a patch
|
||
(@pxref{Contributing}). Well, if you need help, we will be happy to
|
||
help you too. Once the patch is committed in the Guix repository, the
|
||
new package automatically gets built on the supported platforms by
|
||
@url{http://hydra.gnu.org/gnu/master, our continuous integration
|
||
system}.
|
||
|
||
@cindex substituter
|
||
Users can obtain the new package definition simply by running
|
||
@command{guix pull} (@pxref{Invoking guix pull}). When
|
||
@code{hydra.gnu.org} is done building the package, installing the
|
||
package automatically downloads binaries from there
|
||
(@pxref{Substitutes}). The only place where human intervention is
|
||
needed is to review and apply the patch.
|
||
|
||
|
||
@menu
|
||
* Software Freedom:: What may go into the distribution.
|
||
* Package Naming:: What's in a name?
|
||
* Version Numbers:: When the name is not enough.
|
||
* Python Modules:: Taming the snake.
|
||
* Perl Modules:: Little pearls.
|
||
@end menu
|
||
|
||
@node Software Freedom
|
||
@subsection Software Freedom
|
||
|
||
@c Adapted from http://www.gnu.org/philosophy/philosophy.html.
|
||
|
||
The GNU operating system has been developed so that users can have
|
||
freedom in their computing. GNU is @dfn{free software}, meaning that
|
||
users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
|
||
essential freedoms}: to run the program, to study and change the program
|
||
in source code form, to redistribute exact copies, and to distribute
|
||
modified versions. Packages found in the GNU distribution provide only
|
||
software that conveys these four freedoms.
|
||
|
||
In addition, the GNU distribution follow the
|
||
@url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
|
||
software distribution guidelines}. Among other things, these guidelines
|
||
reject non-free firmware, recommendations of non-free software, and
|
||
discuss ways to deal with trademarks and patents.
|
||
|
||
Some packages contain a small and optional subset that violates the
|
||
above guidelines, for instance because this subset is itself non-free
|
||
code. When that happens, the offending items are removed with
|
||
appropriate patches or code snippets in the package definition's
|
||
@code{origin} form (@pxref{Defining Packages}). That way, @code{guix
|
||
build --source} returns the ``freed'' source rather than the unmodified
|
||
upstream source.
|
||
|
||
|
||
@node Package Naming
|
||
@subsection Package Naming
|
||
|
||
A package has actually two names associated with it:
|
||
First, there is the name of the @emph{Scheme variable}, the one following
|
||
@code{define-public}. By this name, the package can be made known in the
|
||
Scheme code, for instance as input to another package. Second, there is
|
||
the string in the @code{name} field of a package definition. This name
|
||
is used by package management commands such as
|
||
@command{guix package} and @command{guix build}.
|
||
|
||
Both are usually the same and correspond to the lowercase conversion of
|
||
the project name chosen upstream, with underscores replaced with
|
||
hyphens. For instance, GNUnet is available as @code{gnunet}, and
|
||
SDL_net as @code{sdl-net}.
|
||
|
||
We do not add @code{lib} prefixes for library packages, unless these are
|
||
already part of the official project name. But see @pxref{Python
|
||
Modules} and @ref{Perl Modules} for special rules concerning modules for
|
||
the Python and Perl languages.
|
||
|
||
|
||
@node Version Numbers
|
||
@subsection Version Numbers
|
||
|
||
We usually package only the latest version of a given free software
|
||
project. But sometimes, for instance for incompatible library versions,
|
||
two (or more) versions of the same package are needed. These require
|
||
different Scheme variable names. We use the name as defined
|
||
in @ref{Package Naming}
|
||
for the most recent version; previous versions use the same name, suffixed
|
||
by @code{-} and the smallest prefix of the version number that may
|
||
distinguish the two versions.
|
||
|
||
The name inside the package definition is the same for all versions of a
|
||
package and does not contain any version number.
|
||
|
||
For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
|
||
|
||
@example
|
||
(define-public gtk+
|
||
(package
|
||
(name "gtk+")
|
||
(version "3.9.12")
|
||
...))
|
||
(define-public gtk+-2
|
||
(package
|
||
(name "gtk+")
|
||
(version "2.24.20")
|
||
...))
|
||
@end example
|
||
If we also wanted GTK+ 3.8.2, this would be packaged as
|
||
@example
|
||
(define-public gtk+-3.8
|
||
(package
|
||
(name "gtk+")
|
||
(version "3.8.2")
|
||
...))
|
||
@end example
|
||
|
||
|
||
@node Python Modules
|
||
@subsection Python Modules
|
||
|
||
We currently package Python 2 and Python 3, under the Scheme variable names
|
||
@code{python-2} and @code{python} as explained in @ref{Version Numbers}.
|
||
To avoid confusion and naming clashes with other programming languages, it
|
||
seems desirable that the name of a package for a Python module contains
|
||
the word @code{python}.
|
||
|
||
Some modules are compatible with only one version of Python, others with both.
|
||
If the package Foo compiles only with Python 3, we name it
|
||
@code{python-foo}; if it compiles only with Python 2, we name it
|
||
@code{python2-foo}. If it is compatible with both versions, we create two
|
||
packages with the corresponding names.
|
||
|
||
If a project already contains the word @code{python}, we drop this;
|
||
for instance, the module python-dateutil is packaged under the names
|
||
@code{python-dateutil} and @code{python2-dateutil}.
|
||
|
||
|
||
@node Perl Modules
|
||
@subsection Perl Modules
|
||
|
||
Perl programs standing for themselves are named as any other package,
|
||
using the lowercase upstream name.
|
||
For Perl packages containing a single class, we use the lowercase class name,
|
||
replace all occurrences of @code{::} by dashes and prepend the prefix
|
||
@code{perl-}.
|
||
So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
|
||
Modules containing several classes keep their lowercase upstream name and
|
||
are also prepended by @code{perl-}. Such modules tend to have the word
|
||
@code{perl} somewhere in their name, which gets dropped in favor of the
|
||
prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
|
||
|
||
|
||
|
||
@node Bootstrapping
|
||
@section Bootstrapping
|
||
|
||
@c Adapted from the ELS 2013 paper.
|
||
|
||
@cindex bootstrapping
|
||
|
||
Bootstrapping in our context refers to how the distribution gets built
|
||
``from nothing''. Remember that the build environment of a derivation
|
||
contains nothing but its declared inputs (@pxref{Introduction}). So
|
||
there's an obvious chicken-and-egg problem: how does the first package
|
||
get built? How does the first compiler get compiled? Note that this is
|
||
a question of interest only to the curious hacker, not to the regular
|
||
user, so you can shamelessly skip this section if you consider yourself
|
||
a ``regular user''.
|
||
|
||
@cindex bootstrap binaries
|
||
The GNU system is primarily made of C code, with libc at its core. The
|
||
GNU build system itself assumes the availability of a Bourne shell and
|
||
command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
|
||
`grep'. Furthermore, build programs---programs that run
|
||
@code{./configure}, @code{make}, etc.---are written in Guile Scheme
|
||
(@pxref{Derivations}). Consequently, to be able to build anything at
|
||
all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
|
||
Binutils, libc, and the other packages mentioned above---the
|
||
@dfn{bootstrap binaries}.
|
||
|
||
These bootstrap binaries are ``taken for granted'', though we can also
|
||
re-create them if needed (more on that later).
|
||
|
||
@unnumberedsubsec Preparing to Use the Bootstrap Binaries
|
||
|
||
@c As of Emacs 24.3, Info-mode displays the image, but since it's a
|
||
@c large image, it's hard to scroll. Oh well.
|
||
@image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
|
||
|
||
The figure above shows the very beginning of the dependency graph of the
|
||
distribution, corresponding to the package definitions of the @code{(gnu
|
||
packages bootstrap)} module. At this level of detail, things are
|
||
slightly complex. First, Guile itself consists of an ELF executable,
|
||
along with many source and compiled Scheme files that are dynamically
|
||
loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
|
||
tarball shown in this graph. This tarball is part of Guix's ``source''
|
||
distribution, and gets inserted into the store with @code{add-to-store}
|
||
(@pxref{The Store}).
|
||
|
||
But how do we write a derivation that unpacks this tarball and adds it
|
||
to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
|
||
derivation---the first one that gets built---uses @code{bash} as its
|
||
builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
|
||
@code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
|
||
@file{xz}, and @file{mkdir} are statically-linked binaries, also part of
|
||
the Guix source distribution, whose sole purpose is to allow the Guile
|
||
tarball to be unpacked.
|
||
|
||
Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
|
||
Guile that can be used to run subsequent build programs. Its first task
|
||
is to download tarballs containing the other pre-built binaries---this
|
||
is what the @code{.tar.xz.drv} derivations do. Guix modules such as
|
||
@code{ftp-client.scm} are used for this purpose. The
|
||
@code{module-import.drv} derivations import those modules in a directory
|
||
in the store, using the original layout. The
|
||
@code{module-import-compiled.drv} derivations compile those modules, and
|
||
write them in an output directory with the right layout. This
|
||
corresponds to the @code{#:modules} argument of
|
||
@code{build-expression->derivation} (@pxref{Derivations}).
|
||
|
||
Finally, the various tarballs are unpacked by the
|
||
derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
|
||
etc., at which point we have a working C tool chain.
|
||
|
||
|
||
@unnumberedsubsec Building the Build Tools
|
||
|
||
@c TODO: Add a package-level dependency graph generated from (gnu
|
||
@c packages base).
|
||
|
||
Bootstrapping is complete when we have a full tool chain that does not
|
||
depend on the pre-built bootstrap tools discussed above. This
|
||
no-dependency requirement is verified by checking whether the files of
|
||
the final tool chain contain references to the @file{/gnu/store}
|
||
directories of the bootstrap inputs. The process that leads to this
|
||
``final'' tool chain is described by the package definitions found in
|
||
the @code{(gnu packages base)} module.
|
||
|
||
@c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
|
||
The first tool that gets built with the bootstrap binaries is
|
||
GNU Make, which is a prerequisite for all the following packages.
|
||
From there Findutils and Diffutils get built.
|
||
|
||
Then come the first-stage Binutils and GCC, built as pseudo cross
|
||
tools---i.e., with @code{--target} equal to @code{--host}. They are
|
||
used to build libc. Thanks to this cross-build trick, this libc is
|
||
guaranteed not to hold any reference to the initial tool chain.
|
||
|
||
From there the final Binutils and GCC are built. GCC uses @code{ld}
|
||
from the final Binutils, and links programs against the just-built libc.
|
||
This tool chain is used to build the other packages used by Guix and by
|
||
the GNU Build System: Guile, Bash, Coreutils, etc.
|
||
|
||
And voilà! At this point we have the complete set of build tools that
|
||
the GNU Build System expects. These are in the @code{%final-inputs}
|
||
variable of the @code{(gnu packages commencement)} module, and are
|
||
implicitly used by any package that uses @code{gnu-build-system}
|
||
(@pxref{Defining Packages}).
|
||
|
||
|
||
@unnumberedsubsec Building the Bootstrap Binaries
|
||
|
||
Because the final tool chain does not depend on the bootstrap binaries,
|
||
those rarely need to be updated. Nevertheless, it is useful to have an
|
||
automated way to produce them, should an update occur, and this is what
|
||
the @code{(gnu packages make-bootstrap)} module provides.
|
||
|
||
The following command builds the tarballs containing the bootstrap
|
||
binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
|
||
of Coreutils and other basic command-line tools):
|
||
|
||
@example
|
||
guix build bootstrap-tarballs
|
||
@end example
|
||
|
||
The generated tarballs are those that should be referred to in the
|
||
@code{(gnu packages bootstrap)} module mentioned at the beginning of
|
||
this section.
|
||
|
||
Still here? Then perhaps by now you've started to wonder: when do we
|
||
reach a fixed point? That is an interesting question! The answer is
|
||
unknown, but if you would like to investigate further (and have
|
||
significant computational and storage resources to do so), then let us
|
||
know.
|
||
|
||
@node Porting
|
||
@section Porting to a New Platform
|
||
|
||
As discussed above, the GNU distribution is self-contained, and
|
||
self-containment is achieved by relying on pre-built ``bootstrap
|
||
binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
|
||
operating system kernel, CPU architecture, and application binary
|
||
interface (ABI). Thus, to port the distribution to a platform that is
|
||
not yet supported, one must build those bootstrap binaries, and update
|
||
the @code{(gnu packages bootstrap)} module to use them on that platform.
|
||
|
||
Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
|
||
When everything goes well, and assuming the GNU tool chain supports the
|
||
target platform, this can be as simple as running a command like this
|
||
one:
|
||
|
||
@example
|
||
guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
|
||
@end example
|
||
|
||
Once these are built, the @code{(gnu packages bootstrap)} module needs
|
||
to be updated to refer to these binaries on the target platform. In
|
||
addition, the @code{glibc-dynamic-linker} procedure in that module must
|
||
be augmented to return the right file name for libc's dynamic linker on
|
||
that platform; likewise, @code{system->linux-architecture} in @code{(gnu
|
||
packages linux)} must be taught about the new platform.
|
||
|
||
In practice, there may be some complications. First, it may be that the
|
||
extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
|
||
above) is not recognized by all the GNU tools. Typically, glibc
|
||
recognizes some of these, whereas GCC uses an extra @code{--with-abi}
|
||
configure flag (see @code{gcc.scm} for examples of how to handle this).
|
||
Second, some of the required packages could fail to build for that
|
||
platform. Lastly, the generated binaries could be broken for some
|
||
reason.
|
||
|
||
|
||
@c *********************************************************************
|
||
@node Contributing
|
||
@chapter Contributing
|
||
|
||
This project is a cooperative effort, and we need your help to make it
|
||
grow! Please get in touch with us on @email{guix-devel@@gnu.org} and
|
||
@code{#guix} on the Freenode IRC network. We welcome ideas, bug
|
||
reports, patches, and anything that may be helpful to the project. We
|
||
particularly welcome help on packaging (@pxref{Packaging Guidelines}).
|
||
|
||
Please see the
|
||
@url{http://git.savannah.gnu.org/cgit/guix.git/tree/HACKING,
|
||
@file{HACKING} file} that comes with the Guix source code for practical
|
||
details about contributions.
|
||
|
||
|
||
@c *********************************************************************
|
||
@node Acknowledgments
|
||
@chapter Acknowledgments
|
||
|
||
Guix is based on the Nix package manager, which was designed and
|
||
implemented by Eelco Dolstra. Nix pioneered functional package
|
||
management, and promoted unprecedented features, such as transactional
|
||
package upgrades and rollbacks, per-user profiles, and referentially
|
||
transparent build processes. Without this work, Guix would not exist.
|
||
|
||
The Nix-based software distributions, Nixpkgs and NixOS, have also been
|
||
an inspiration for Guix.
|
||
|
||
@c *********************************************************************
|
||
@node GNU Free Documentation License
|
||
@appendix GNU Free Documentation License
|
||
|
||
@include fdl-1.3.texi
|
||
|
||
@c *********************************************************************
|
||
@node Concept Index
|
||
@unnumbered Concept Index
|
||
@printindex cp
|
||
|
||
@node Programming Index
|
||
@unnumbered Programming Index
|
||
@syncodeindex tp fn
|
||
@syncodeindex vr fn
|
||
@printindex fn
|
||
|
||
@bye
|
||
|
||
@c Local Variables:
|
||
@c ispell-local-dictionary: "american";
|
||
@c End:
|