| 1 | \input texinfo |
| 2 | @c -*-texinfo-*- |
| 3 | |
| 4 | @c %**start of header |
| 5 | @setfilename guix.info |
| 6 | @documentencoding UTF-8 |
| 7 | @settitle GNU Guix Reference Manual |
| 8 | @c %**end of header |
| 9 | |
| 10 | @include version.texi |
| 11 | |
| 12 | @copying |
| 13 | Copyright @copyright{} 2012, 2013, 2014, 2015 Ludovic Courtès@* |
| 14 | Copyright @copyright{} 2013, 2014 Andreas Enge@* |
| 15 | Copyright @copyright{} 2013 Nikita Karetnikov |
| 16 | |
| 17 | Permission is granted to copy, distribute and/or modify this document |
| 18 | under the terms of the GNU Free Documentation License, Version 1.3 or |
| 19 | any later version published by the Free Software Foundation; with no |
| 20 | Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A |
| 21 | copy of the license is included in the section entitled ``GNU Free |
| 22 | Documentation License''. |
| 23 | @end copying |
| 24 | |
| 25 | @dircategory Package management |
| 26 | @direntry |
| 27 | * guix: (guix). Guix, the functional package manager. |
| 28 | * guix package: (guix)Invoking guix package |
| 29 | Managing packages with Guix. |
| 30 | * guix build: (guix)Invoking guix build |
| 31 | Building packages with Guix. |
| 32 | * guix system: (guix)Invoking guix system |
| 33 | Managing the operating system configuration. |
| 34 | @end direntry |
| 35 | |
| 36 | @dircategory Software development |
| 37 | @direntry |
| 38 | * guix environment: (guix)Invoking guix environment |
| 39 | Building development environments with Guix. |
| 40 | @end direntry |
| 41 | |
| 42 | @titlepage |
| 43 | @title GNU Guix Reference Manual |
| 44 | @subtitle Using the GNU Guix Functional Package Manager |
| 45 | @author Ludovic Courtès |
| 46 | @author Andreas Enge |
| 47 | @author Nikita Karetnikov |
| 48 | |
| 49 | @page |
| 50 | @vskip 0pt plus 1filll |
| 51 | Edition @value{EDITION} @* |
| 52 | @value{UPDATED} @* |
| 53 | |
| 54 | @insertcopying |
| 55 | @end titlepage |
| 56 | |
| 57 | @contents |
| 58 | |
| 59 | @c ********************************************************************* |
| 60 | @node Top |
| 61 | @top GNU Guix |
| 62 | |
| 63 | This document describes GNU Guix version @value{VERSION}, a functional |
| 64 | package management tool written for the GNU system. |
| 65 | |
| 66 | @menu |
| 67 | * Introduction:: What is Guix about? |
| 68 | * Installation:: Installing Guix. |
| 69 | * Package Management:: Package installation, upgrade, etc. |
| 70 | * Programming Interface:: Using Guix in Scheme. |
| 71 | * Utilities:: Package management commands. |
| 72 | * GNU Distribution:: Software for your friendly GNU system. |
| 73 | * Contributing:: Your help needed! |
| 74 | |
| 75 | * Acknowledgments:: Thanks! |
| 76 | * GNU Free Documentation License:: The license of this manual. |
| 77 | * Concept Index:: Concepts. |
| 78 | * Programming Index:: Data types, functions, and variables. |
| 79 | |
| 80 | @detailmenu |
| 81 | --- The Detailed Node Listing --- |
| 82 | |
| 83 | Installation |
| 84 | |
| 85 | * Requirements:: Software needed to build and run Guix. |
| 86 | * Setting Up the Daemon:: Preparing the build daemon's environment. |
| 87 | * Invoking guix-daemon:: Running the build daemon. |
| 88 | |
| 89 | Setting Up the Daemon |
| 90 | |
| 91 | * Build Environment Setup:: Preparing the isolated build environment. |
| 92 | * Daemon Offload Setup:: Offloading builds to remote machines. |
| 93 | |
| 94 | Package Management |
| 95 | |
| 96 | * Features:: How Guix will make your life brighter. |
| 97 | * Invoking guix package:: Package installation, removal, etc. |
| 98 | * Emacs Interface:: Package management from Emacs. |
| 99 | * Substitutes:: Downloading pre-built binaries. |
| 100 | * Packages with Multiple Outputs:: Single source package, multiple outputs. |
| 101 | * Invoking guix gc:: Running the garbage collector. |
| 102 | * Invoking guix pull:: Fetching the latest Guix and distribution. |
| 103 | * Invoking guix archive:: Exporting and importing store files. |
| 104 | |
| 105 | Programming Interface |
| 106 | |
| 107 | * Defining Packages:: Defining new packages. |
| 108 | * Build Systems:: Specifying how packages are built. |
| 109 | * The Store:: Manipulating the package store. |
| 110 | * Derivations:: Low-level interface to package derivations. |
| 111 | * The Store Monad:: Purely functional interface to the store. |
| 112 | * G-Expressions:: Manipulating build expressions. |
| 113 | |
| 114 | Utilities |
| 115 | |
| 116 | * Invoking guix build:: Building packages from the command line. |
| 117 | * Invoking guix download:: Downloading a file and printing its hash. |
| 118 | * Invoking guix hash:: Computing the cryptographic hash of a file. |
| 119 | * Invoking guix import:: Importing package definitions. |
| 120 | * Invoking guix refresh:: Updating package definitions. |
| 121 | * Invoking guix lint:: Finding errors in package definitions. |
| 122 | * Invoking guix environment:: Setting up development environments. |
| 123 | |
| 124 | GNU Distribution |
| 125 | |
| 126 | * System Installation:: Installing the whole operating system. |
| 127 | * System Configuration:: Configuring the operating system. |
| 128 | * Installing Debugging Files:: Feeding the debugger. |
| 129 | * Security Updates:: Deploying security fixes quickly. |
| 130 | * Package Modules:: Packages from the programmer's viewpoint. |
| 131 | * Packaging Guidelines:: Growing the distribution. |
| 132 | * Bootstrapping:: GNU/Linux built from scratch. |
| 133 | * Porting:: Targeting another platform or kernel. |
| 134 | |
| 135 | System Configuration |
| 136 | |
| 137 | * Using the Configuration System:: Customizing your GNU system. |
| 138 | * operating-system Reference:: Detail of operating-system declarations. |
| 139 | * File Systems:: Configuring file system mounts. |
| 140 | * Mapped Devices:: Block device extra processing. |
| 141 | * User Accounts:: Specifying user accounts. |
| 142 | * Locales:: Language and cultural convention settings. |
| 143 | * Services:: Specifying system services. |
| 144 | * Setuid Programs:: Programs running with root privileges. |
| 145 | * Name Service Switch:: Configuring libc's name service switch. |
| 146 | * Initial RAM Disk:: Linux-Libre bootstrapping. |
| 147 | * GRUB Configuration:: Configuring the boot loader. |
| 148 | * Invoking guix system:: Instantiating a system configuration. |
| 149 | * Defining Services:: Adding new service definitions. |
| 150 | |
| 151 | Services |
| 152 | |
| 153 | * Base Services:: Essential system services. |
| 154 | * Networking Services:: Network setup, SSH daemon, etc. |
| 155 | * X Window:: Graphical display. |
| 156 | |
| 157 | Packaging Guidelines |
| 158 | |
| 159 | * Software Freedom:: What may go into the distribution. |
| 160 | * Package Naming:: What's in a name? |
| 161 | * Version Numbers:: When the name is not enough. |
| 162 | * Python Modules:: Taming the snake. |
| 163 | * Perl Modules:: Little pearls. |
| 164 | * Fonts:: Fond of fonts. |
| 165 | |
| 166 | @end detailmenu |
| 167 | @end menu |
| 168 | |
| 169 | @c ********************************************************************* |
| 170 | @node Introduction |
| 171 | @chapter Introduction |
| 172 | |
| 173 | GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks'' |
| 174 | using the international phonetic alphabet (IPA).} is a functional |
| 175 | package management tool for the GNU system. Package management consists |
| 176 | of all activities that relate to building packages from sources, |
| 177 | honoring their build-time and run-time dependencies, |
| 178 | installing packages in user environments, upgrading installed packages |
| 179 | to new versions or rolling back to a previous set, removing unused |
| 180 | software packages, etc. |
| 181 | |
| 182 | @cindex functional package management |
| 183 | The term @dfn{functional} refers to a specific package management |
| 184 | discipline. In Guix, the package build and installation process is seen |
| 185 | as a function, in the mathematical sense. That function takes inputs, |
| 186 | such as build scripts, a compiler, and libraries, and |
| 187 | returns an installed package. As a pure function, its result depends |
| 188 | solely on its inputs---for instance, it cannot refer to software or |
| 189 | scripts that were not explicitly passed as inputs. A build function |
| 190 | always produces the same result when passed a given set of inputs. It |
| 191 | cannot alter the system's environment in |
| 192 | any way; for instance, it cannot create, modify, or delete files outside |
| 193 | of its build and installation directories. This is achieved by running |
| 194 | build processes in isolated environments (or @dfn{containers}), where only their |
| 195 | explicit inputs are visible. |
| 196 | |
| 197 | @cindex store |
| 198 | The result of package build functions is @dfn{cached} in the file |
| 199 | system, in a special directory called @dfn{the store} (@pxref{The |
| 200 | Store}). Each package is installed in a directory of its own, in the |
| 201 | store---by default under @file{/gnu/store}. The directory name contains |
| 202 | a hash of all the inputs used to build that package; thus, changing an |
| 203 | input yields a different directory name. |
| 204 | |
| 205 | This approach is the foundation of Guix's salient features: support for |
| 206 | transactional package upgrade and rollback, per-user installation, and |
| 207 | garbage collection of packages (@pxref{Features}). |
| 208 | |
| 209 | Guix has a command-line interface, which allows users to build, install, |
| 210 | upgrade, and remove packages, as well as a Scheme programming interface. |
| 211 | |
| 212 | @cindex Guix System Distribution |
| 213 | @cindex GSD |
| 214 | Last but not least, Guix is used to build a distribution of the GNU |
| 215 | system, with many GNU and non-GNU free software packages. The Guix |
| 216 | System Distribution, or GNU@tie{}GSD, takes advantage of the core |
| 217 | properties of Guix at the system level. With GNU@tie{}GSD, users |
| 218 | @emph{declare} all aspects of the operating system configuration, and |
| 219 | Guix takes care of instantiating that configuration in a reproducible, |
| 220 | stateless fashion. @xref{GNU Distribution}. |
| 221 | |
| 222 | @c ********************************************************************* |
| 223 | @node Installation |
| 224 | @chapter Installation |
| 225 | |
| 226 | GNU Guix is available for download from its website at |
| 227 | @url{http://www.gnu.org/software/guix/}. This section describes the |
| 228 | software requirements of Guix, as well as how to install it and get |
| 229 | ready to use it. |
| 230 | |
| 231 | Note that this section is concerned with the installation of the package |
| 232 | manager, which can be done on top of a running GNU/Linux system. If, |
| 233 | instead, you want to install the complete GNU operating system, |
| 234 | @pxref{System Installation}. |
| 235 | |
| 236 | The build procedure for Guix is the same as for other GNU software, and |
| 237 | is not covered here. Please see the files @file{README} and |
| 238 | @file{INSTALL} in the Guix source tree for additional details. |
| 239 | |
| 240 | @menu |
| 241 | * Requirements:: Software needed to build and run Guix. |
| 242 | * Setting Up the Daemon:: Preparing the build daemon's environment. |
| 243 | * Invoking guix-daemon:: Running the build daemon. |
| 244 | @end menu |
| 245 | |
| 246 | @node Requirements |
| 247 | @section Requirements |
| 248 | |
| 249 | GNU Guix depends on the following packages: |
| 250 | |
| 251 | @itemize |
| 252 | @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.5 or later; |
| 253 | @item @url{http://gnupg.org/, GNU libgcrypt}; |
| 254 | @end itemize |
| 255 | |
| 256 | The following dependencies are optional: |
| 257 | |
| 258 | @itemize |
| 259 | @item |
| 260 | Installing |
| 261 | @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will |
| 262 | allow you to use the @command{guix import pypi} command (@pxref{Invoking |
| 263 | guix import}). It is of |
| 264 | interest primarily for developers and not for casual users. |
| 265 | @item |
| 266 | Installing @uref{http://gnutls.org/, GnuTLS-Guile} will |
| 267 | allow you to access @code{https} URLs with the @command{guix download} |
| 268 | command (@pxref{Invoking guix download}), the @command{guix import pypi} |
| 269 | command, and the @command{guix import cpan} command. This is primarily |
| 270 | of interest to developers. @xref{Guile Preparations, how to install the |
| 271 | GnuTLS bindings for Guile,, gnutls-guile, GnuTLS-Guile}. |
| 272 | @end itemize |
| 273 | |
| 274 | Unless @code{--disable-daemon} was passed to @command{configure}, the |
| 275 | following packages are also needed: |
| 276 | |
| 277 | @itemize |
| 278 | @item @url{http://sqlite.org, SQLite 3} |
| 279 | @item @url{http://www.bzip.org, libbz2} |
| 280 | @item @url{http://gcc.gnu.org, GCC's g++} |
| 281 | @end itemize |
| 282 | |
| 283 | When a working installation of @url{http://nixos.org/nix/, the Nix package |
| 284 | manager} is available, you |
| 285 | can instead configure Guix with @code{--disable-daemon}. In that case, |
| 286 | Nix replaces the three dependencies above. |
| 287 | |
| 288 | Guix is compatible with Nix, so it is possible to share the same store |
| 289 | between both. To do so, you must pass @command{configure} not only the |
| 290 | same @code{--with-store-dir} value, but also the same |
| 291 | @code{--localstatedir} value. The latter is essential because it |
| 292 | specifies where the database that stores metadata about the store is |
| 293 | located, among other things. The default values for Nix are |
| 294 | @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}. |
| 295 | Note that @code{--disable-daemon} is not required if |
| 296 | your goal is to share the store with Nix. |
| 297 | |
| 298 | @node Setting Up the Daemon |
| 299 | @section Setting Up the Daemon |
| 300 | |
| 301 | @cindex daemon |
| 302 | Operations such as building a package or running the garbage collector |
| 303 | are all performed by a specialized process, the @dfn{build daemon}, on |
| 304 | behalf of clients. Only the daemon may access the store and its |
| 305 | associated database. Thus, any operation that manipulates the store |
| 306 | goes through the daemon. For instance, command-line tools such as |
| 307 | @command{guix package} and @command{guix build} communicate with the |
| 308 | daemon (@i{via} remote procedure calls) to instruct it what to do. |
| 309 | |
| 310 | The following sections explain how to prepare the build daemon's |
| 311 | environment. |
| 312 | |
| 313 | @menu |
| 314 | * Build Environment Setup:: Preparing the isolated build environment. |
| 315 | * Daemon Offload Setup:: Offloading builds to remote machines. |
| 316 | @end menu |
| 317 | |
| 318 | @node Build Environment Setup |
| 319 | @subsection Build Environment Setup |
| 320 | |
| 321 | In a standard multi-user setup, Guix and its daemon---the |
| 322 | @command{guix-daemon} program---are installed by the system |
| 323 | administrator; @file{/gnu/store} is owned by @code{root} and |
| 324 | @command{guix-daemon} runs as @code{root}. Unprivileged users may use |
| 325 | Guix tools to build packages or otherwise access the store, and the |
| 326 | daemon will do it on their behalf, ensuring that the store is kept in a |
| 327 | consistent state, and allowing built packages to be shared among users. |
| 328 | |
| 329 | @cindex build users |
| 330 | When @command{guix-daemon} runs as @code{root}, you may not want package |
| 331 | build processes themselves to run as @code{root} too, for obvious |
| 332 | security reasons. To avoid that, a special pool of @dfn{build users} |
| 333 | should be created for use by build processes started by the daemon. |
| 334 | These build users need not have a shell and a home directory: they will |
| 335 | just be used when the daemon drops @code{root} privileges in build |
| 336 | processes. Having several such users allows the daemon to launch |
| 337 | distinct build processes under separate UIDs, which guarantees that they |
| 338 | do not interfere with each other---an essential feature since builds are |
| 339 | regarded as pure functions (@pxref{Introduction}). |
| 340 | |
| 341 | On a GNU/Linux system, a build user pool may be created like this (using |
| 342 | Bash syntax and the @code{shadow} commands): |
| 343 | |
| 344 | @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html |
| 345 | @c for why `-G' is needed. |
| 346 | @example |
| 347 | # groupadd guix-builder |
| 348 | # for i in `seq 1 10`; |
| 349 | do |
| 350 | useradd -g guix-builder -G guix-builder \ |
| 351 | -d /var/empty -s `which nologin` \ |
| 352 | -c "Guix build user $i" --system \ |
| 353 | guix-builder$i; |
| 354 | done |
| 355 | @end example |
| 356 | |
| 357 | The @file{/gnu/store} directory (or whichever was specified with the |
| 358 | @code{--with-store-dir} option) must have ownership and permissions as |
| 359 | follows: |
| 360 | |
| 361 | @example |
| 362 | # chgrp guix-builder /gnu/store |
| 363 | # chmod 1775 /gnu/store |
| 364 | @end example |
| 365 | |
| 366 | @noindent |
| 367 | The @code{guix-daemon} program may then be run as @code{root} with: |
| 368 | |
| 369 | @example |
| 370 | # guix-daemon --build-users-group=guix-builder |
| 371 | @end example |
| 372 | |
| 373 | @cindex chroot |
| 374 | @noindent |
| 375 | This way, the daemon starts build processes in a chroot, under one of |
| 376 | the @code{guix-builder} users. On GNU/Linux, by default, the chroot |
| 377 | environment contains nothing but: |
| 378 | |
| 379 | @c Keep this list in sync with libstore/build.cc! ----------------------- |
| 380 | @itemize |
| 381 | @item |
| 382 | a minimal @code{/dev} directory, created mostly independently from the |
| 383 | host @code{/dev}@footnote{``Mostly'', because while the set of files |
| 384 | that appear in the chroot's @code{/dev} is fixed, most of these files |
| 385 | can only be created if the host has them.}; |
| 386 | |
| 387 | @item |
| 388 | the @code{/proc} directory; it only shows the container's processes |
| 389 | since a separate PID name space is used; |
| 390 | |
| 391 | @item |
| 392 | @file{/etc/passwd} with an entry for the current user and an entry for |
| 393 | user @file{nobody}; |
| 394 | |
| 395 | @item |
| 396 | @file{/etc/group} with an entry for the user's group; |
| 397 | |
| 398 | @item |
| 399 | @file{/etc/hosts} with an entry that maps @code{localhost} to |
| 400 | @code{127.0.0.1}; |
| 401 | |
| 402 | @item |
| 403 | a writable @file{/tmp} directory. |
| 404 | @end itemize |
| 405 | |
| 406 | If you are installing Guix as an unprivileged user, it is still |
| 407 | possible to run @command{guix-daemon}. However, build processes will |
| 408 | not be isolated from one another, and not from the rest of the system. |
| 409 | Thus, build processes may interfere with each other, and may access |
| 410 | programs, libraries, and other files available on the system---making it |
| 411 | much harder to view them as @emph{pure} functions. |
| 412 | |
| 413 | |
| 414 | @node Daemon Offload Setup |
| 415 | @subsection Using the Offload Facility |
| 416 | |
| 417 | @cindex offloading |
| 418 | @cindex build hook |
| 419 | When desired, the build daemon can @dfn{offload} |
| 420 | derivation builds to other machines |
| 421 | running Guix, using the @code{offload} @dfn{build hook}. When that |
| 422 | feature is enabled, a list of user-specified build machines is read from |
| 423 | @file{/etc/guix/machines.scm}; anytime a build is requested, for |
| 424 | instance via @code{guix build}, the daemon attempts to offload it to one |
| 425 | of the machines that satisfies the derivation's constraints, in |
| 426 | particular its system type---e.g., @file{x86_64-linux}. Missing |
| 427 | prerequisites for the build are copied over SSH to the target machine, |
| 428 | which then proceeds with the build; upon success the output(s) of the |
| 429 | build are copied back to the initial machine. |
| 430 | |
| 431 | The @file{/etc/guix/machines.scm} file typically looks like this: |
| 432 | |
| 433 | @example |
| 434 | (list (build-machine |
| 435 | (name "eightysix.example.org") |
| 436 | (system "x86_64-linux") |
| 437 | (user "bob") |
| 438 | (speed 2.)) ; incredibly fast! |
| 439 | |
| 440 | (build-machine |
| 441 | (name "meeps.example.org") |
| 442 | (system "mips64el-linux") |
| 443 | (user "alice") |
| 444 | (private-key |
| 445 | (string-append (getenv "HOME") |
| 446 | "/.ssh/id-rsa-for-guix")))) |
| 447 | @end example |
| 448 | |
| 449 | @noindent |
| 450 | In the example above we specify a list of two build machines, one for |
| 451 | the @code{x86_64} architecture and one for the @code{mips64el} |
| 452 | architecture. |
| 453 | |
| 454 | In fact, this file is---not surprisingly!---a Scheme file that is |
| 455 | evaluated when the @code{offload} hook is started. Its return value |
| 456 | must be a list of @code{build-machine} objects. While this example |
| 457 | shows a fixed list of build machines, one could imagine, say, using |
| 458 | DNS-SD to return a list of potential build machines discovered in the |
| 459 | local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using |
| 460 | Avahi in Guile Scheme Programs}). The @code{build-machine} data type is |
| 461 | detailed below. |
| 462 | |
| 463 | @deftp {Data Type} build-machine |
| 464 | This data type represents build machines the daemon may offload builds |
| 465 | to. The important fields are: |
| 466 | |
| 467 | @table @code |
| 468 | |
| 469 | @item name |
| 470 | The remote machine's host name. |
| 471 | |
| 472 | @item system |
| 473 | The remote machine's system type---e.g., @code{"x86_64-linux"}. |
| 474 | |
| 475 | @item user |
| 476 | The user account to use when connecting to the remote machine over SSH. |
| 477 | Note that the SSH key pair must @emph{not} be passphrase-protected, to |
| 478 | allow non-interactive logins. |
| 479 | |
| 480 | @end table |
| 481 | |
| 482 | A number of optional fields may be specified: |
| 483 | |
| 484 | @table @code |
| 485 | |
| 486 | @item port |
| 487 | Port number of the machine's SSH server (default: 22). |
| 488 | |
| 489 | @item private-key |
| 490 | The SSH private key file to use when connecting to the machine. |
| 491 | |
| 492 | @item parallel-builds |
| 493 | The number of builds that may run in parallel on the machine (1 by |
| 494 | default.) |
| 495 | |
| 496 | @item speed |
| 497 | A ``relative speed factor''. The offload scheduler will tend to prefer |
| 498 | machines with a higher speed factor. |
| 499 | |
| 500 | @item features |
| 501 | A list of strings denoting specific features supported by the machine. |
| 502 | An example is @code{"kvm"} for machines that have the KVM Linux modules |
| 503 | and corresponding hardware support. Derivations can request features by |
| 504 | name, and they will be scheduled on matching build machines. |
| 505 | |
| 506 | @end table |
| 507 | @end deftp |
| 508 | |
| 509 | The @code{guix} command must be in the search path on the build |
| 510 | machines, since offloading works by invoking the @code{guix archive} and |
| 511 | @code{guix build} commands. |
| 512 | |
| 513 | There's one last thing to do once @file{machines.scm} is in place. As |
| 514 | explained above, when offloading, files are transferred back and forth |
| 515 | between the machine stores. For this to work, you need to generate a |
| 516 | key pair to allow the daemon to export signed archives of files from the |
| 517 | store (@pxref{Invoking guix archive}): |
| 518 | |
| 519 | @example |
| 520 | # guix archive --generate-key |
| 521 | @end example |
| 522 | |
| 523 | @noindent |
| 524 | Thus, when receiving files, a machine's build daemon can make sure they |
| 525 | are genuine, have not been tampered with, and that they are signed by an |
| 526 | authorized key. |
| 527 | |
| 528 | |
| 529 | @node Invoking guix-daemon |
| 530 | @section Invoking @command{guix-daemon} |
| 531 | |
| 532 | The @command{guix-daemon} program implements all the functionality to |
| 533 | access the store. This includes launching build processes, running the |
| 534 | garbage collector, querying the availability of a build result, etc. It |
| 535 | is normally run as @code{root} like this: |
| 536 | |
| 537 | @example |
| 538 | # guix-daemon --build-users-group=guix-builder |
| 539 | @end example |
| 540 | |
| 541 | @noindent |
| 542 | For details on how to set it up, @pxref{Setting Up the Daemon}. |
| 543 | |
| 544 | @cindex chroot |
| 545 | @cindex container, build environment |
| 546 | @cindex build environment |
| 547 | @cindex reproducible builds |
| 548 | By default, @command{guix-daemon} launches build processes under |
| 549 | different UIDs, taken from the build group specified with |
| 550 | @code{--build-users-group}. In addition, each build process is run in a |
| 551 | chroot environment that only contains the subset of the store that the |
| 552 | build process depends on, as specified by its derivation |
| 553 | (@pxref{Programming Interface, derivation}), plus a set of specific |
| 554 | system directories. By default, the latter contains @file{/dev} and |
| 555 | @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a |
| 556 | @dfn{container}: in addition to having its own file system tree, it has |
| 557 | a separate mount name space, its own PID name space, network name space, |
| 558 | etc. This helps achieve reproducible builds (@pxref{Features}). |
| 559 | |
| 560 | When the daemon performs a build on behalf of the user, it creates a |
| 561 | build directory under @file{/tmp} or under the directory specified by |
| 562 | its @code{TMPDIR} environment variable; this directory is shared with |
| 563 | the container for the duration of the build. Be aware that using a |
| 564 | directory other than @file{/tmp} can affect build results---for example, |
| 565 | with a longer directory name, a build process that uses Unix-domain |
| 566 | sockets might hit the name length limitation for @code{sun_path}, which |
| 567 | it would otherwise not hit. |
| 568 | |
| 569 | The build directory is automatically deleted upon completion, unless the |
| 570 | build failed and the client specified @option{--keep-failed} |
| 571 | (@pxref{Invoking guix build, @option{--keep-failed}}). |
| 572 | |
| 573 | The following command-line options are supported: |
| 574 | |
| 575 | @table @code |
| 576 | @item --build-users-group=@var{group} |
| 577 | Take users from @var{group} to run build processes (@pxref{Setting Up |
| 578 | the Daemon, build users}). |
| 579 | |
| 580 | @item --no-substitutes |
| 581 | @cindex substitutes |
| 582 | Do not use substitutes for build products. That is, always build things |
| 583 | locally instead of allowing downloads of pre-built binaries |
| 584 | (@pxref{Substitutes}). |
| 585 | |
| 586 | By default substitutes are used, unless the client---such as the |
| 587 | @command{guix package} command---is explicitly invoked with |
| 588 | @code{--no-substitutes}. |
| 589 | |
| 590 | When the daemon runs with @code{--no-substitutes}, clients can still |
| 591 | explicitly enable substitution @i{via} the @code{set-build-options} |
| 592 | remote procedure call (@pxref{The Store}). |
| 593 | |
| 594 | @item --substitute-urls=@var{urls} |
| 595 | Consider @var{urls} the default whitespace-separated list of substitute |
| 596 | source URLs. When this option is omitted, @code{http://hydra.gnu.org} |
| 597 | is used. |
| 598 | |
| 599 | This means that substitutes may be downloaded from @var{urls}, as long |
| 600 | as they are signed by a trusted signature (@pxref{Substitutes}). |
| 601 | |
| 602 | @cindex build hook |
| 603 | @item --no-build-hook |
| 604 | Do not use the @dfn{build hook}. |
| 605 | |
| 606 | The build hook is a helper program that the daemon can start and to |
| 607 | which it submits build requests. This mechanism is used to offload |
| 608 | builds to other machines (@pxref{Daemon Offload Setup}). |
| 609 | |
| 610 | @item --cache-failures |
| 611 | Cache build failures. By default, only successful builds are cached. |
| 612 | |
| 613 | @item --cores=@var{n} |
| 614 | @itemx -c @var{n} |
| 615 | Use @var{n} CPU cores to build each derivation; @code{0} means as many |
| 616 | as available. |
| 617 | |
| 618 | The default value is @code{0}, but it may be overridden by clients, such |
| 619 | as the @code{--cores} option of @command{guix build} (@pxref{Invoking |
| 620 | guix build}). |
| 621 | |
| 622 | The effect is to define the @code{NIX_BUILD_CORES} environment variable |
| 623 | in the build process, which can then use it to exploit internal |
| 624 | parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}. |
| 625 | |
| 626 | @item --max-jobs=@var{n} |
| 627 | @itemx -M @var{n} |
| 628 | Allow at most @var{n} build jobs in parallel. The default value is |
| 629 | @code{1}. Setting it to @code{0} means that no builds will be performed |
| 630 | locally; instead, the daemon will offload builds (@pxref{Daemon Offload |
| 631 | Setup}), or simply fail. |
| 632 | |
| 633 | @item --debug |
| 634 | Produce debugging output. |
| 635 | |
| 636 | This is useful to debug daemon start-up issues, but then it may be |
| 637 | overridden by clients, for example the @code{--verbosity} option of |
| 638 | @command{guix build} (@pxref{Invoking guix build}). |
| 639 | |
| 640 | @item --chroot-directory=@var{dir} |
| 641 | Add @var{dir} to the build chroot. |
| 642 | |
| 643 | Doing this may change the result of build processes---for instance if |
| 644 | they use optional dependencies found in @var{dir} when it is available, |
| 645 | and not otherwise. For that reason, it is not recommended to do so. |
| 646 | Instead, make sure that each derivation declares all the inputs that it |
| 647 | needs. |
| 648 | |
| 649 | @item --disable-chroot |
| 650 | Disable chroot builds. |
| 651 | |
| 652 | Using this option is not recommended since, again, it would allow build |
| 653 | processes to gain access to undeclared dependencies. |
| 654 | |
| 655 | @item --disable-log-compression |
| 656 | Disable compression of the build logs. |
| 657 | |
| 658 | Unless @code{--lose-logs} is used, all the build logs are kept in the |
| 659 | @var{localstatedir}. To save space, the daemon automatically compresses |
| 660 | them with bzip2 by default. This option disables that. |
| 661 | |
| 662 | @item --disable-deduplication |
| 663 | @cindex deduplication |
| 664 | Disable automatic file ``deduplication'' in the store. |
| 665 | |
| 666 | By default, files added to the store are automatically ``deduplicated'': |
| 667 | if a newly added file is identical to another one found in the store, |
| 668 | the daemon makes the new file a hard link to the other file. This can |
| 669 | noticeably reduce disk usage, at the expense of slightly increasde |
| 670 | input/output load at the end of a build process. This option disables |
| 671 | this optimization. |
| 672 | |
| 673 | @item --gc-keep-outputs[=yes|no] |
| 674 | Tell whether the garbage collector (GC) must keep outputs of live |
| 675 | derivations. |
| 676 | |
| 677 | When set to ``yes'', the GC will keep the outputs of any live derivation |
| 678 | available in the store---the @code{.drv} files. The default is ``no'', |
| 679 | meaning that derivation outputs are kept only if they are GC roots. |
| 680 | |
| 681 | @item --gc-keep-derivations[=yes|no] |
| 682 | Tell whether the garbage collector (GC) must keep derivations |
| 683 | corresponding to live outputs. |
| 684 | |
| 685 | When set to ``yes'', as is the case by default, the GC keeps |
| 686 | derivations---i.e., @code{.drv} files---as long as at least one of their |
| 687 | outputs is live. This allows users to keep track of the origins of |
| 688 | items in their store. Setting it to ``no'' saves a bit of disk space. |
| 689 | |
| 690 | Note that when both @code{--gc-keep-derivations} and |
| 691 | @code{--gc-keep-outputs} are used, the effect is to keep all the build |
| 692 | prerequisites (the sources, compiler, libraries, and other build-time |
| 693 | tools) of live objects in the store, regardless of whether these |
| 694 | prerequisites are live. This is convenient for developers since it |
| 695 | saves rebuilds or downloads. |
| 696 | |
| 697 | @item --impersonate-linux-2.6 |
| 698 | On Linux-based systems, impersonate Linux 2.6. This means that the |
| 699 | kernel's @code{uname} system call will report 2.6 as the release number. |
| 700 | |
| 701 | This might be helpful to build programs that (usually wrongfully) depend |
| 702 | on the kernel version number. |
| 703 | |
| 704 | @item --lose-logs |
| 705 | Do not keep build logs. By default they are kept under |
| 706 | @code{@var{localstatedir}/guix/log}. |
| 707 | |
| 708 | @item --system=@var{system} |
| 709 | Assume @var{system} as the current system type. By default it is the |
| 710 | architecture/kernel pair found at configure time, such as |
| 711 | @code{x86_64-linux}. |
| 712 | |
| 713 | @item --listen=@var{socket} |
| 714 | Listen for connections on @var{socket}, the file name of a Unix-domain |
| 715 | socket. The default socket is |
| 716 | @file{@var{localstatedir}/daemon-socket/socket}. This option is only |
| 717 | useful in exceptional circumstances, such as if you need to run several |
| 718 | daemons on the same machine. |
| 719 | @end table |
| 720 | |
| 721 | |
| 722 | @c ********************************************************************* |
| 723 | @node Package Management |
| 724 | @chapter Package Management |
| 725 | |
| 726 | The purpose of GNU Guix is to allow users to easily install, upgrade, and |
| 727 | remove software packages, without having to know about their build |
| 728 | procedure or dependencies. Guix also goes beyond this obvious set of |
| 729 | features. |
| 730 | |
| 731 | This chapter describes the main features of Guix, as well as the package |
| 732 | management tools it provides. Two user interfaces are provided for |
| 733 | routine package management tasks: a command-line interface |
| 734 | (@pxref{Invoking guix package, @code{guix package}}), and a visual user |
| 735 | interface in Emacs (@pxref{Emacs Interface}). |
| 736 | |
| 737 | @menu |
| 738 | * Features:: How Guix will make your life brighter. |
| 739 | * Invoking guix package:: Package installation, removal, etc. |
| 740 | * Emacs Interface:: Package management from Emacs. |
| 741 | * Substitutes:: Downloading pre-built binaries. |
| 742 | * Packages with Multiple Outputs:: Single source package, multiple outputs. |
| 743 | * Invoking guix gc:: Running the garbage collector. |
| 744 | * Invoking guix pull:: Fetching the latest Guix and distribution. |
| 745 | * Invoking guix archive:: Exporting and importing store files. |
| 746 | @end menu |
| 747 | |
| 748 | @node Features |
| 749 | @section Features |
| 750 | |
| 751 | When using Guix, each package ends up in the @dfn{package store}, in its |
| 752 | own directory---something that resembles |
| 753 | @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string |
| 754 | (note that Guix comes with an Emacs extension to shorten those file |
| 755 | names, @pxref{Emacs Prettify}.) |
| 756 | |
| 757 | Instead of referring to these directories, users have their own |
| 758 | @dfn{profile}, which points to the packages that they actually want to |
| 759 | use. These profiles are stored within each user's home directory, at |
| 760 | @code{$HOME/.guix-profile}. |
| 761 | |
| 762 | For example, @code{alice} installs GCC 4.7.2. As a result, |
| 763 | @file{/home/alice/.guix-profile/bin/gcc} points to |
| 764 | @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine, |
| 765 | @code{bob} had already installed GCC 4.8.0. The profile of @code{bob} |
| 766 | simply continues to point to |
| 767 | @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC |
| 768 | coexist on the same system without any interference. |
| 769 | |
| 770 | The @command{guix package} command is the central tool to manage |
| 771 | packages (@pxref{Invoking guix package}). It operates on those per-user |
| 772 | profiles, and can be used @emph{with normal user privileges}. |
| 773 | |
| 774 | The command provides the obvious install, remove, and upgrade |
| 775 | operations. Each invocation is actually a @emph{transaction}: either |
| 776 | the specified operation succeeds, or nothing happens. Thus, if the |
| 777 | @command{guix package} process is terminated during the transaction, |
| 778 | or if a power outage occurs during the transaction, then the user's |
| 779 | profile remains in its previous state, and remains usable. |
| 780 | |
| 781 | In addition, any package transaction may be @emph{rolled back}. So, if, |
| 782 | for example, an upgrade installs a new version of a package that turns |
| 783 | out to have a serious bug, users may roll back to the previous instance |
| 784 | of their profile, which was known to work well. Similarly, the global |
| 785 | system configuration is subject to transactional upgrades and roll-back |
| 786 | (@pxref{Using the Configuration System}). |
| 787 | |
| 788 | All those packages in the package store may be @emph{garbage-collected}. |
| 789 | Guix can determine which packages are still referenced by the user |
| 790 | profiles, and remove those that are provably no longer referenced |
| 791 | (@pxref{Invoking guix gc}). Users may also explicitly remove old |
| 792 | generations of their profile so that the packages they refer to can be |
| 793 | collected. |
| 794 | |
| 795 | @cindex reproducibility |
| 796 | @cindex reproducible builds |
| 797 | Finally, Guix takes a @dfn{purely functional} approach to package |
| 798 | management, as described in the introduction (@pxref{Introduction}). |
| 799 | Each @file{/gnu/store} package directory name contains a hash of all the |
| 800 | inputs that were used to build that package---compiler, libraries, build |
| 801 | scripts, etc. This direct correspondence allows users to make sure a |
| 802 | given package installation matches the current state of their |
| 803 | distribution. It also helps maximize @dfn{build reproducibility}: |
| 804 | thanks to the isolated build environments that are used, a given build |
| 805 | is likely to yield bit-identical files when performed on different |
| 806 | machines (@pxref{Invoking guix-daemon, container}). |
| 807 | |
| 808 | @cindex substitutes |
| 809 | This foundation allows Guix to support @dfn{transparent binary/source |
| 810 | deployment}. When a pre-built binary for a @file{/gnu/store} item is |
| 811 | available from an external source---a @dfn{substitute}, Guix just |
| 812 | downloads it and unpacks it; |
| 813 | otherwise, it builds the package from source, locally |
| 814 | (@pxref{Substitutes}). |
| 815 | |
| 816 | Control over the build environment is a feature that is also useful for |
| 817 | developers. The @command{guix environment} command allows developers of |
| 818 | a package to quickly set up the right development environment for their |
| 819 | package, without having to manually install the package's dependencies |
| 820 | in their profile (@pxref{Invoking guix environment}). |
| 821 | |
| 822 | @node Invoking guix package |
| 823 | @section Invoking @command{guix package} |
| 824 | |
| 825 | The @command{guix package} command is the tool that allows users to |
| 826 | install, upgrade, and remove packages, as well as rolling back to |
| 827 | previous configurations. It operates only on the user's own profile, |
| 828 | and works with normal user privileges (@pxref{Features}). Its syntax |
| 829 | is: |
| 830 | |
| 831 | @example |
| 832 | guix package @var{options} |
| 833 | @end example |
| 834 | |
| 835 | Primarily, @var{options} specifies the operations to be performed during |
| 836 | the transaction. Upon completion, a new profile is created, but |
| 837 | previous generations of the profile remain available, should the user |
| 838 | want to roll back. |
| 839 | |
| 840 | For example, to remove @code{lua} and install @code{guile} and |
| 841 | @code{guile-cairo} in a single transaction: |
| 842 | |
| 843 | @example |
| 844 | guix package -r lua -i guile guile-cairo |
| 845 | @end example |
| 846 | |
| 847 | For each user, a symlink to the user's default profile is automatically |
| 848 | created in @file{$HOME/.guix-profile}. This symlink always points to the |
| 849 | current generation of the user's default profile. Thus, users can add |
| 850 | @file{$HOME/.guix-profile/bin} to their @code{PATH} environment |
| 851 | variable, and so on. |
| 852 | |
| 853 | In a multi-user setup, user profiles are stored in a place registered as |
| 854 | a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points |
| 855 | to (@pxref{Invoking guix gc}). That directory is normally |
| 856 | @code{@var{localstatedir}/profiles/per-user/@var{user}}, where |
| 857 | @var{localstatedir} is the value passed to @code{configure} as |
| 858 | @code{--localstatedir}, and @var{user} is the user name. The |
| 859 | @file{per-user} directory is created when @command{guix-daemon} is |
| 860 | started, and the @var{user} sub-directory is created by @command{guix |
| 861 | package}. |
| 862 | |
| 863 | The @var{options} can be among the following: |
| 864 | |
| 865 | @table @code |
| 866 | |
| 867 | @item --install=@var{package} @dots{} |
| 868 | @itemx -i @var{package} @dots{} |
| 869 | Install the specified @var{package}s. |
| 870 | |
| 871 | Each @var{package} may specify either a simple package name, such as |
| 872 | @code{guile}, or a package name followed by a hyphen and version number, |
| 873 | such as @code{guile-1.8.8}. If no version number is specified, the |
| 874 | newest available version will be selected. In addition, @var{package} |
| 875 | may contain a colon, followed by the name of one of the outputs of the |
| 876 | package, as in @code{gcc:doc} or @code{binutils-2.22:lib} |
| 877 | (@pxref{Packages with Multiple Outputs}). Packages with a corresponding |
| 878 | name (and optionally version) are searched for among the GNU |
| 879 | distribution modules (@pxref{Package Modules}). |
| 880 | |
| 881 | @cindex propagated inputs |
| 882 | Sometimes packages have @dfn{propagated inputs}: these are dependencies |
| 883 | that automatically get installed along with the required package. |
| 884 | |
| 885 | An example is the GNU MPC library: its C header files refer to those of |
| 886 | the GNU MPFR library, which in turn refer to those of the GMP library. |
| 887 | Thus, when installing MPC, the MPFR and GMP libraries also get installed |
| 888 | in the profile; removing MPC also removes MPFR and GMP---unless they had |
| 889 | also been explicitly installed independently. |
| 890 | |
| 891 | Besides, packages sometimes rely on the definition of environment |
| 892 | variables for their search paths (see explanation of |
| 893 | @code{--search-paths} below). Any missing or possibly incorrect |
| 894 | environment variable definitions are reported here. |
| 895 | |
| 896 | @c XXX: keep me up-to-date |
| 897 | Finally, when installing a GNU package, the tool reports the |
| 898 | availability of a newer upstream version. In the future, it may provide |
| 899 | the option of installing directly from the upstream version, even if |
| 900 | that version is not yet in the distribution. |
| 901 | |
| 902 | @item --install-from-expression=@var{exp} |
| 903 | @itemx -e @var{exp} |
| 904 | Install the package @var{exp} evaluates to. |
| 905 | |
| 906 | @var{exp} must be a Scheme expression that evaluates to a |
| 907 | @code{<package>} object. This option is notably useful to disambiguate |
| 908 | between same-named variants of a package, with expressions such as |
| 909 | @code{(@@ (gnu packages base) guile-final)}. |
| 910 | |
| 911 | Note that this option installs the first output of the specified |
| 912 | package, which may be insufficient when needing a specific output of a |
| 913 | multiple-output package. |
| 914 | |
| 915 | @item --remove=@var{package} @dots{} |
| 916 | @itemx -r @var{package} @dots{} |
| 917 | Remove the specified @var{package}s. |
| 918 | |
| 919 | As for @code{--install}, each @var{package} may specify a version number |
| 920 | and/or output name in addition to the package name. For instance, |
| 921 | @code{-r glibc:debug} would remove the @code{debug} output of |
| 922 | @code{glibc}. |
| 923 | |
| 924 | @item --upgrade[=@var{regexp} @dots{}] |
| 925 | @itemx -u [@var{regexp} @dots{}] |
| 926 | Upgrade all the installed packages. If one or more @var{regexp}s are |
| 927 | specified, upgrade only installed packages whose name matches a |
| 928 | @var{regexp}. |
| 929 | |
| 930 | Note that this upgrades package to the latest version of packages found |
| 931 | in the distribution currently installed. To update your distribution, |
| 932 | you should regularly run @command{guix pull} (@pxref{Invoking guix |
| 933 | pull}). |
| 934 | |
| 935 | @item --roll-back |
| 936 | Roll back to the previous @dfn{generation} of the profile---i.e., undo |
| 937 | the last transaction. |
| 938 | |
| 939 | When combined with options such as @code{--install}, roll back occurs |
| 940 | before any other actions. |
| 941 | |
| 942 | When rolling back from the first generation that actually contains |
| 943 | installed packages, the profile is made to point to the @dfn{zeroth |
| 944 | generation}, which contains no files apart from its own meta-data. |
| 945 | |
| 946 | Installing, removing, or upgrading packages from a generation that has |
| 947 | been rolled back to overwrites previous future generations. Thus, the |
| 948 | history of a profile's generations is always linear. |
| 949 | |
| 950 | @item --switch-generation=@var{pattern} |
| 951 | @itemx -S @var{pattern} |
| 952 | Switch to a particular generation defined by @var{pattern}. |
| 953 | |
| 954 | @var{pattern} may be either a generation number or a number prefixed |
| 955 | with ``+'' or ``-''. The latter means: move forward/backward by a |
| 956 | specified number of generations. For example, if you want to return to |
| 957 | the latest generation after @code{--roll-back}, use |
| 958 | @code{--switch-generation=+1}. |
| 959 | |
| 960 | The difference between @code{--roll-back} and |
| 961 | @code{--switch-generation=-1} is that @code{--switch-generation} will |
| 962 | not make a zeroth generation, so if a specified generation does not |
| 963 | exist, the current generation will not be changed. |
| 964 | |
| 965 | @item --search-paths |
| 966 | @cindex search paths |
| 967 | Report environment variable definitions, in Bash syntax, that may be |
| 968 | needed in order to use the set of installed packages. These environment |
| 969 | variables are used to specify @dfn{search paths} for files used by some |
| 970 | of the installed packages. |
| 971 | |
| 972 | For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH} |
| 973 | environment variables to be defined so it can look for headers and |
| 974 | libraries in the user's profile (@pxref{Environment Variables,,, gcc, |
| 975 | Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C |
| 976 | library are installed in the profile, then @code{--search-paths} will |
| 977 | suggest setting these variables to @code{@var{profile}/include} and |
| 978 | @code{@var{profile}/lib}, respectively. |
| 979 | |
| 980 | @item --profile=@var{profile} |
| 981 | @itemx -p @var{profile} |
| 982 | Use @var{profile} instead of the user's default profile. |
| 983 | |
| 984 | @item --verbose |
| 985 | Produce verbose output. In particular, emit the environment's build log |
| 986 | on the standard error port. |
| 987 | |
| 988 | @item --bootstrap |
| 989 | Use the bootstrap Guile to build the profile. This option is only |
| 990 | useful to distribution developers. |
| 991 | |
| 992 | @end table |
| 993 | |
| 994 | In addition to these actions @command{guix package} supports the |
| 995 | following options to query the current state of a profile, or the |
| 996 | availability of packages: |
| 997 | |
| 998 | @table @option |
| 999 | |
| 1000 | @item --search=@var{regexp} |
| 1001 | @itemx -s @var{regexp} |
| 1002 | List the available packages whose synopsis or description matches |
| 1003 | @var{regexp}. Print all the meta-data of matching packages in |
| 1004 | @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, |
| 1005 | GNU recutils manual}). |
| 1006 | |
| 1007 | This allows specific fields to be extracted using the @command{recsel} |
| 1008 | command, for instance: |
| 1009 | |
| 1010 | @example |
| 1011 | $ guix package -s malloc | recsel -p name,version |
| 1012 | name: glibc |
| 1013 | version: 2.17 |
| 1014 | |
| 1015 | name: libgc |
| 1016 | version: 7.2alpha6 |
| 1017 | @end example |
| 1018 | |
| 1019 | Similarly, to show the name of all the packages available under the |
| 1020 | terms of the GNU@tie{}LGPL version 3: |
| 1021 | |
| 1022 | @example |
| 1023 | $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"' |
| 1024 | name: elfutils |
| 1025 | |
| 1026 | name: gmp |
| 1027 | @dots{} |
| 1028 | @end example |
| 1029 | |
| 1030 | @item --show=@var{package} |
| 1031 | Show details about @var{package}, taken from the list of available packages, in |
| 1032 | @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU |
| 1033 | recutils manual}). |
| 1034 | |
| 1035 | @example |
| 1036 | $ guix package --show=python | recsel -p name,version |
| 1037 | name: python |
| 1038 | version: 2.7.6 |
| 1039 | |
| 1040 | name: python |
| 1041 | version: 3.3.5 |
| 1042 | @end example |
| 1043 | |
| 1044 | You may also specify the full name of a package to only get details about a |
| 1045 | specific version of it: |
| 1046 | @example |
| 1047 | $ guix package --show=python-3.3.5 | recsel -p name,version |
| 1048 | name: python |
| 1049 | version: 3.3.5 |
| 1050 | @end example |
| 1051 | |
| 1052 | |
| 1053 | |
| 1054 | @item --list-installed[=@var{regexp}] |
| 1055 | @itemx -I [@var{regexp}] |
| 1056 | List the currently installed packages in the specified profile, with the |
| 1057 | most recently installed packages shown last. When @var{regexp} is |
| 1058 | specified, list only installed packages whose name matches @var{regexp}. |
| 1059 | |
| 1060 | For each installed package, print the following items, separated by |
| 1061 | tabs: the package name, its version string, the part of the package that |
| 1062 | is installed (for instance, @code{out} for the default output, |
| 1063 | @code{include} for its headers, etc.), and the path of this package in |
| 1064 | the store. |
| 1065 | |
| 1066 | @item --list-available[=@var{regexp}] |
| 1067 | @itemx -A [@var{regexp}] |
| 1068 | List packages currently available in the software distribution |
| 1069 | (@pxref{GNU Distribution}). When @var{regexp} is specified, list only |
| 1070 | installed packages whose name matches @var{regexp}. |
| 1071 | |
| 1072 | For each package, print the following items separated by tabs: its name, |
| 1073 | its version string, the parts of the package (@pxref{Packages with |
| 1074 | Multiple Outputs}), and the source location of its definition. |
| 1075 | |
| 1076 | @item --list-generations[=@var{pattern}] |
| 1077 | @itemx -l [@var{pattern}] |
| 1078 | Return a list of generations along with their creation dates; for each |
| 1079 | generation, show the installed packages, with the most recently |
| 1080 | installed packages shown last. Note that the zeroth generation is never |
| 1081 | shown. |
| 1082 | |
| 1083 | For each installed package, print the following items, separated by |
| 1084 | tabs: the name of a package, its version string, the part of the package |
| 1085 | that is installed (@pxref{Packages with Multiple Outputs}), and the |
| 1086 | location of this package in the store. |
| 1087 | |
| 1088 | When @var{pattern} is used, the command returns only matching |
| 1089 | generations. Valid patterns include: |
| 1090 | |
| 1091 | @itemize |
| 1092 | @item @emph{Integers and comma-separated integers}. Both patterns denote |
| 1093 | generation numbers. For instance, @code{--list-generations=1} returns |
| 1094 | the first one. |
| 1095 | |
| 1096 | And @code{--list-generations=1,8,2} outputs three generations in the |
| 1097 | specified order. Neither spaces nor trailing commas are allowed. |
| 1098 | |
| 1099 | @item @emph{Ranges}. @code{--list-generations=2..9} prints the |
| 1100 | specified generations and everything in between. Note that the start of |
| 1101 | a range must be lesser than its end. |
| 1102 | |
| 1103 | It is also possible to omit the endpoint. For example, |
| 1104 | @code{--list-generations=2..}, returns all generations starting from the |
| 1105 | second one. |
| 1106 | |
| 1107 | @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks, |
| 1108 | or months by passing an integer along with the first letter of the |
| 1109 | duration. For example, @code{--list-generations=20d} lists generations |
| 1110 | that are up to 20 days old. |
| 1111 | @end itemize |
| 1112 | |
| 1113 | @item --delete-generations[=@var{pattern}] |
| 1114 | @itemx -d [@var{pattern}] |
| 1115 | When @var{pattern} is omitted, delete all generations except the current |
| 1116 | one. |
| 1117 | |
| 1118 | This command accepts the same patterns as @option{--list-generations}. |
| 1119 | When @var{pattern} is specified, delete the matching generations. When |
| 1120 | @var{pattern} specifies a duration, generations @emph{older} than the |
| 1121 | specified duration match. For instance, @code{--delete-generations=1m} |
| 1122 | deletes generations that are more than one month old. |
| 1123 | |
| 1124 | If the current generation matches, it is deleted atomically---i.e., by |
| 1125 | switching to the previous available generation. Note that the zeroth |
| 1126 | generation is never deleted. |
| 1127 | |
| 1128 | Note that deleting generations prevents roll-back to them. |
| 1129 | Consequently, this command must be used with care. |
| 1130 | |
| 1131 | @end table |
| 1132 | |
| 1133 | Finally, since @command{guix package} may actually start build |
| 1134 | processes, it supports all the common build options that @command{guix |
| 1135 | build} supports (@pxref{Invoking guix build, common build options}). |
| 1136 | |
| 1137 | @include emacs.texi |
| 1138 | |
| 1139 | @node Substitutes |
| 1140 | @section Substitutes |
| 1141 | |
| 1142 | @cindex substitutes |
| 1143 | @cindex pre-built binaries |
| 1144 | Guix supports transparent source/binary deployment, which means that it |
| 1145 | can either build things locally, or download pre-built items from a |
| 1146 | server. We call these pre-built items @dfn{substitutes}---they are |
| 1147 | substitutes for local build results. In many cases, downloading a |
| 1148 | substitute is much faster than building things locally. |
| 1149 | |
| 1150 | Substitutes can be anything resulting from a derivation build |
| 1151 | (@pxref{Derivations}). Of course, in the common case, they are |
| 1152 | pre-built package binaries, but source tarballs, for instance, which |
| 1153 | also result from derivation builds, can be available as substitutes. |
| 1154 | |
| 1155 | The @code{hydra.gnu.org} server is a front-end to a build farm that |
| 1156 | builds packages from the GNU distribution continuously for some |
| 1157 | architectures, and makes them available as substitutes. This is the |
| 1158 | default source of substitutes; it can be overridden by passing |
| 1159 | @command{guix-daemon} the @code{--substitute-urls} option |
| 1160 | (@pxref{Invoking guix-daemon}). |
| 1161 | |
| 1162 | @cindex security |
| 1163 | @cindex digital signatures |
| 1164 | To allow Guix to download substitutes from @code{hydra.gnu.org}, you |
| 1165 | must add its public key to the access control list (ACL) of archive |
| 1166 | imports, using the @command{guix archive} command (@pxref{Invoking guix |
| 1167 | archive}). Doing so implies that you trust @code{hydra.gnu.org} to not |
| 1168 | be compromised and to serve genuine substitutes. |
| 1169 | |
| 1170 | This public key is installed along with Guix, in |
| 1171 | @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is |
| 1172 | the installation prefix of Guix. If you installed Guix from source, |
| 1173 | make sure you checked the GPG signature of |
| 1174 | @file{guix-@value{VERSION}.tar.gz}, which contains this public key file. |
| 1175 | Then, you can run something like this: |
| 1176 | |
| 1177 | @example |
| 1178 | # guix archive --authorize < hydra.gnu.org.pub |
| 1179 | @end example |
| 1180 | |
| 1181 | Once this is in place, the output of a command like @code{guix build} |
| 1182 | should change from something like: |
| 1183 | |
| 1184 | @example |
| 1185 | $ guix build emacs --dry-run |
| 1186 | The following derivations would be built: |
| 1187 | /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv |
| 1188 | /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv |
| 1189 | /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv |
| 1190 | /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv |
| 1191 | @dots{} |
| 1192 | @end example |
| 1193 | |
| 1194 | @noindent |
| 1195 | to something like: |
| 1196 | |
| 1197 | @example |
| 1198 | $ guix build emacs --dry-run |
| 1199 | The following files would be downloaded: |
| 1200 | /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3 |
| 1201 | /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d |
| 1202 | /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16 |
| 1203 | /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7 |
| 1204 | @dots{} |
| 1205 | @end example |
| 1206 | |
| 1207 | @noindent |
| 1208 | This indicates that substitutes from @code{hydra.gnu.org} are usable and |
| 1209 | will be downloaded, when possible, for future builds. |
| 1210 | |
| 1211 | Guix ignores substitutes that are not signed, or that are not signed by |
| 1212 | one of the keys listed in the ACL. It also detects and raises an error |
| 1213 | when attempting to use a substitute that has been tampered with. |
| 1214 | |
| 1215 | The substitute mechanism can be disabled globally by running |
| 1216 | @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking |
| 1217 | guix-daemon}). It can also be disabled temporarily by passing the |
| 1218 | @code{--no-substitutes} option to @command{guix package}, @command{guix |
| 1219 | build}, and other command-line tools. |
| 1220 | |
| 1221 | |
| 1222 | Today, each individual's control over their own computing is at the |
| 1223 | mercy of institutions, corporations, and groups with enough power and |
| 1224 | determination to subvert the computing infrastructure and exploit its |
| 1225 | weaknesses. While using @code{hydra.gnu.org} substitutes can be |
| 1226 | convenient, we encourage users to also build on their own, or even run |
| 1227 | their own build farm, such that @code{hydra.gnu.org} is less of an |
| 1228 | interesting target. |
| 1229 | |
| 1230 | Guix has the foundations to maximize build reproducibility |
| 1231 | (@pxref{Features}). In most cases, independent builds of a given |
| 1232 | package or derivation should yield bit-identical results. Thus, through |
| 1233 | a diverse set of independent package builds, we can strengthen the |
| 1234 | integrity of our systems. |
| 1235 | |
| 1236 | In the future, we want Guix to have support to publish and retrieve |
| 1237 | binaries to/from other users, in a peer-to-peer fashion. If you would |
| 1238 | like to discuss this project, join us on @email{guix-devel@@gnu.org}. |
| 1239 | |
| 1240 | |
| 1241 | @node Packages with Multiple Outputs |
| 1242 | @section Packages with Multiple Outputs |
| 1243 | |
| 1244 | @cindex multiple-output packages |
| 1245 | @cindex package outputs |
| 1246 | |
| 1247 | Often, packages defined in Guix have a single @dfn{output}---i.e., the |
| 1248 | source package leads exactly one directory in the store. When running |
| 1249 | @command{guix package -i glibc}, one installs the default output of the |
| 1250 | GNU libc package; the default output is called @code{out}, but its name |
| 1251 | can be omitted as shown in this command. In this particular case, the |
| 1252 | default output of @code{glibc} contains all the C header files, shared |
| 1253 | libraries, static libraries, Info documentation, and other supporting |
| 1254 | files. |
| 1255 | |
| 1256 | Sometimes it is more appropriate to separate the various types of files |
| 1257 | produced from a single source package into separate outputs. For |
| 1258 | instance, the GLib C library (used by GTK+ and related packages) |
| 1259 | installs more than 20 MiB of reference documentation as HTML pages. |
| 1260 | To save space for users who do not need it, the documentation goes to a |
| 1261 | separate output, called @code{doc}. To install the main GLib output, |
| 1262 | which contains everything but the documentation, one would run: |
| 1263 | |
| 1264 | @example |
| 1265 | guix package -i glib |
| 1266 | @end example |
| 1267 | |
| 1268 | The command to install its documentation is: |
| 1269 | |
| 1270 | @example |
| 1271 | guix package -i glib:doc |
| 1272 | @end example |
| 1273 | |
| 1274 | Some packages install programs with different ``dependency footprints''. |
| 1275 | For instance, the WordNet package install both command-line tools and |
| 1276 | graphical user interfaces (GUIs). The former depend solely on the C |
| 1277 | library, whereas the latter depend on Tcl/Tk and the underlying X |
| 1278 | libraries. In this case, we leave the command-line tools in the default |
| 1279 | output, whereas the GUIs are in a separate output. This allows users |
| 1280 | who do not need the GUIs to save space. |
| 1281 | |
| 1282 | There are several such multiple-output packages in the GNU distribution. |
| 1283 | Other conventional output names include @code{lib} for libraries and |
| 1284 | possibly header files, @code{bin} for stand-alone programs, and |
| 1285 | @code{debug} for debugging information (@pxref{Installing Debugging |
| 1286 | Files}). The outputs of a packages are listed in the third column of |
| 1287 | the output of @command{guix package --list-available} (@pxref{Invoking |
| 1288 | guix package}). |
| 1289 | |
| 1290 | |
| 1291 | @node Invoking guix gc |
| 1292 | @section Invoking @command{guix gc} |
| 1293 | |
| 1294 | @cindex garbage collector |
| 1295 | Packages that are installed but not used may be @dfn{garbage-collected}. |
| 1296 | The @command{guix gc} command allows users to explicitly run the garbage |
| 1297 | collector to reclaim space from the @file{/gnu/store} directory. |
| 1298 | |
| 1299 | The garbage collector has a set of known @dfn{roots}: any file under |
| 1300 | @file{/gnu/store} reachable from a root is considered @dfn{live} and |
| 1301 | cannot be deleted; any other file is considered @dfn{dead} and may be |
| 1302 | deleted. The set of garbage collector roots includes default user |
| 1303 | profiles, and may be augmented with @command{guix build --root}, for |
| 1304 | example (@pxref{Invoking guix build}). |
| 1305 | |
| 1306 | Prior to running @code{guix gc --collect-garbage} to make space, it is |
| 1307 | often useful to remove old generations from user profiles; that way, old |
| 1308 | package builds referenced by those generations can be reclaimed. This |
| 1309 | is achieved by running @code{guix package --delete-generations} |
| 1310 | (@pxref{Invoking guix package}). |
| 1311 | |
| 1312 | The @command{guix gc} command has three modes of operation: it can be |
| 1313 | used to garbage-collect any dead files (the default), to delete specific |
| 1314 | files (the @code{--delete} option), or to print garbage-collector |
| 1315 | information. The available options are listed below: |
| 1316 | |
| 1317 | @table @code |
| 1318 | @item --collect-garbage[=@var{min}] |
| 1319 | @itemx -C [@var{min}] |
| 1320 | Collect garbage---i.e., unreachable @file{/gnu/store} files and |
| 1321 | sub-directories. This is the default operation when no option is |
| 1322 | specified. |
| 1323 | |
| 1324 | When @var{min} is given, stop once @var{min} bytes have been collected. |
| 1325 | @var{min} may be a number of bytes, or it may include a unit as a |
| 1326 | suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes |
| 1327 | (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}). |
| 1328 | |
| 1329 | When @var{min} is omitted, collect all the garbage. |
| 1330 | |
| 1331 | @item --delete |
| 1332 | @itemx -d |
| 1333 | Attempt to delete all the store files and directories specified as |
| 1334 | arguments. This fails if some of the files are not in the store, or if |
| 1335 | they are still live. |
| 1336 | |
| 1337 | @item --list-dead |
| 1338 | Show the list of dead files and directories still present in the |
| 1339 | store---i.e., files and directories no longer reachable from any root. |
| 1340 | |
| 1341 | @item --list-live |
| 1342 | Show the list of live store files and directories. |
| 1343 | |
| 1344 | @end table |
| 1345 | |
| 1346 | In addition, the references among existing store files can be queried: |
| 1347 | |
| 1348 | @table @code |
| 1349 | |
| 1350 | @item --references |
| 1351 | @itemx --referrers |
| 1352 | List the references (respectively, the referrers) of store files given |
| 1353 | as arguments. |
| 1354 | |
| 1355 | @item --requisites |
| 1356 | @itemx -R |
| 1357 | List the requisites of the store files passed as arguments. Requisites |
| 1358 | include the store files themselves, their references, and the references |
| 1359 | of these, recursively. In other words, the returned list is the |
| 1360 | @dfn{transitive closure} of the store files. |
| 1361 | |
| 1362 | @end table |
| 1363 | |
| 1364 | |
| 1365 | @node Invoking guix pull |
| 1366 | @section Invoking @command{guix pull} |
| 1367 | |
| 1368 | Packages are installed or upgraded to the latest version available in |
| 1369 | the distribution currently available on your local machine. To update |
| 1370 | that distribution, along with the Guix tools, you must run @command{guix |
| 1371 | pull}: the command downloads the latest Guix source code and package |
| 1372 | descriptions, and deploys it. |
| 1373 | |
| 1374 | On completion, @command{guix package} will use packages and package |
| 1375 | versions from this just-retrieved copy of Guix. Not only that, but all |
| 1376 | the Guix commands and Scheme modules will also be taken from that latest |
| 1377 | version. New @command{guix} sub-commands added by the update also |
| 1378 | become available. |
| 1379 | |
| 1380 | The @command{guix pull} command is usually invoked with no arguments, |
| 1381 | but it supports the following options: |
| 1382 | |
| 1383 | @table @code |
| 1384 | @item --verbose |
| 1385 | Produce verbose output, writing build logs to the standard error output. |
| 1386 | |
| 1387 | @item --url=@var{url} |
| 1388 | Download the source tarball of Guix from @var{url}. |
| 1389 | |
| 1390 | By default, the tarball is taken from its canonical address at |
| 1391 | @code{gnu.org}, for the stable branch of Guix. |
| 1392 | |
| 1393 | @item --bootstrap |
| 1394 | Use the bootstrap Guile to build the latest Guix. This option is only |
| 1395 | useful to Guix developers. |
| 1396 | @end table |
| 1397 | |
| 1398 | |
| 1399 | @node Invoking guix archive |
| 1400 | @section Invoking @command{guix archive} |
| 1401 | |
| 1402 | The @command{guix archive} command allows users to @dfn{export} files |
| 1403 | from the store into a single archive, and to later @dfn{import} them. |
| 1404 | In particular, it allows store files to be transferred from one machine |
| 1405 | to another machine's store. For example, to transfer the @code{emacs} |
| 1406 | package to a machine connected over SSH, one would run: |
| 1407 | |
| 1408 | @example |
| 1409 | guix archive --export -r emacs | ssh the-machine guix archive --import |
| 1410 | @end example |
| 1411 | |
| 1412 | @noindent |
| 1413 | Similarly, a complete user profile may be transferred from one machine |
| 1414 | to another like this: |
| 1415 | |
| 1416 | @example |
| 1417 | guix archive --export -r $(readlink -f ~/.guix-profile) | \ |
| 1418 | ssh the-machine guix-archive --import |
| 1419 | @end example |
| 1420 | |
| 1421 | @noindent |
| 1422 | However, note that, in both examples, all of @code{emacs} and the |
| 1423 | profile as well as all of their dependencies are transferred (due to |
| 1424 | @code{-r}), regardless of what is already available in the target |
| 1425 | machine's store. The @code{--missing} option can help figure out which |
| 1426 | items are missing from the target's store. |
| 1427 | |
| 1428 | Archives are stored in the ``Nix archive'' or ``Nar'' format, which is |
| 1429 | comparable in spirit to `tar', but with a few noteworthy differences |
| 1430 | that make it more appropriate for our purposes. First, rather than |
| 1431 | recording all Unix meta-data for each file, the Nar format only mentions |
| 1432 | the file type (regular, directory, or symbolic link); Unix permissions |
| 1433 | and owner/group are dismissed. Second, the order in which directory |
| 1434 | entries are stored always follows the order of file names according to |
| 1435 | the C locale collation order. This makes archive production fully |
| 1436 | deterministic. |
| 1437 | |
| 1438 | When exporting, the daemon digitally signs the contents of the archive, |
| 1439 | and that digital signature is appended. When importing, the daemon |
| 1440 | verifies the signature and rejects the import in case of an invalid |
| 1441 | signature or if the signing key is not authorized. |
| 1442 | @c FIXME: Add xref to daemon doc about signatures. |
| 1443 | |
| 1444 | The main options are: |
| 1445 | |
| 1446 | @table @code |
| 1447 | @item --export |
| 1448 | Export the specified store files or packages (see below.) Write the |
| 1449 | resulting archive to the standard output. |
| 1450 | |
| 1451 | Dependencies are @emph{not} included in the output, unless |
| 1452 | @code{--recursive} is passed. |
| 1453 | |
| 1454 | @item -r |
| 1455 | @itemx --recursive |
| 1456 | When combined with @code{--export}, this instructs @command{guix |
| 1457 | archive} to include dependencies of the given items in the archive. |
| 1458 | Thus, the resulting archive is self-contained: it contains the closure |
| 1459 | of the exported store items. |
| 1460 | |
| 1461 | @item --import |
| 1462 | Read an archive from the standard input, and import the files listed |
| 1463 | therein into the store. Abort if the archive has an invalid digital |
| 1464 | signature, or if it is signed by a public key not among the authorized |
| 1465 | keys (see @code{--authorize} below.) |
| 1466 | |
| 1467 | @item --missing |
| 1468 | Read a list of store file names from the standard input, one per line, |
| 1469 | and write on the standard output the subset of these files missing from |
| 1470 | the store. |
| 1471 | |
| 1472 | @item --generate-key[=@var{parameters}] |
| 1473 | @cindex signing, archives |
| 1474 | Generate a new key pair for the daemons. This is a prerequisite before |
| 1475 | archives can be exported with @code{--export}. Note that this operation |
| 1476 | usually takes time, because it needs to gather enough entropy to |
| 1477 | generate the key pair. |
| 1478 | |
| 1479 | The generated key pair is typically stored under @file{/etc/guix}, in |
| 1480 | @file{signing-key.pub} (public key) and @file{signing-key.sec} (private |
| 1481 | key, which must be kept secret.) When @var{parameters} is omitted, |
| 1482 | an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt |
| 1483 | versions before 1.6.0, it is a 4096-bit RSA key. |
| 1484 | Alternately, @var{parameters} can specify |
| 1485 | @code{genkey} parameters suitable for Libgcrypt (@pxref{General |
| 1486 | public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The |
| 1487 | Libgcrypt Reference Manual}). |
| 1488 | |
| 1489 | @item --authorize |
| 1490 | @cindex authorizing, archives |
| 1491 | Authorize imports signed by the public key passed on standard input. |
| 1492 | The public key must be in ``s-expression advanced format''---i.e., the |
| 1493 | same format as the @file{signing-key.pub} file. |
| 1494 | |
| 1495 | The list of authorized keys is kept in the human-editable file |
| 1496 | @file{/etc/guix/acl}. The file contains |
| 1497 | @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format |
| 1498 | s-expressions''} and is structured as an access-control list in the |
| 1499 | @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure |
| 1500 | (SPKI)}. |
| 1501 | @end table |
| 1502 | |
| 1503 | To export store files as an archive to the standard output, run: |
| 1504 | |
| 1505 | @example |
| 1506 | guix archive --export @var{options} @var{specifications}... |
| 1507 | @end example |
| 1508 | |
| 1509 | @var{specifications} may be either store file names or package |
| 1510 | specifications, as for @command{guix package} (@pxref{Invoking guix |
| 1511 | package}). For instance, the following command creates an archive |
| 1512 | containing the @code{gui} output of the @code{git} package and the main |
| 1513 | output of @code{emacs}: |
| 1514 | |
| 1515 | @example |
| 1516 | guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar |
| 1517 | @end example |
| 1518 | |
| 1519 | If the specified packages are not built yet, @command{guix archive} |
| 1520 | automatically builds them. The build process may be controlled with the |
| 1521 | same options that can be passed to the @command{guix build} command |
| 1522 | (@pxref{Invoking guix build, common build options}). |
| 1523 | |
| 1524 | |
| 1525 | @c ********************************************************************* |
| 1526 | @node Programming Interface |
| 1527 | @chapter Programming Interface |
| 1528 | |
| 1529 | GNU Guix provides several Scheme programming interfaces (APIs) to |
| 1530 | define, build, and query packages. The first interface allows users to |
| 1531 | write high-level package definitions. These definitions refer to |
| 1532 | familiar packaging concepts, such as the name and version of a package, |
| 1533 | its build system, and its dependencies. These definitions can then be |
| 1534 | turned into concrete build actions. |
| 1535 | |
| 1536 | Build actions are performed by the Guix daemon, on behalf of users. In a |
| 1537 | standard setup, the daemon has write access to the store---the |
| 1538 | @file{/gnu/store} directory---whereas users do not. The recommended |
| 1539 | setup also has the daemon perform builds in chroots, under a specific |
| 1540 | build users, to minimize interference with the rest of the system. |
| 1541 | |
| 1542 | @cindex derivation |
| 1543 | Lower-level APIs are available to interact with the daemon and the |
| 1544 | store. To instruct the daemon to perform a build action, users actually |
| 1545 | provide it with a @dfn{derivation}. A derivation is a low-level |
| 1546 | representation of the build actions to be taken, and the environment in |
| 1547 | which they should occur---derivations are to package definitions what |
| 1548 | assembly is to C programs. The term ``derivation'' comes from the fact |
| 1549 | that build results @emph{derive} from them. |
| 1550 | |
| 1551 | This chapter describes all these APIs in turn, starting from high-level |
| 1552 | package definitions. |
| 1553 | |
| 1554 | @menu |
| 1555 | * Defining Packages:: Defining new packages. |
| 1556 | * Build Systems:: Specifying how packages are built. |
| 1557 | * The Store:: Manipulating the package store. |
| 1558 | * Derivations:: Low-level interface to package derivations. |
| 1559 | * The Store Monad:: Purely functional interface to the store. |
| 1560 | * G-Expressions:: Manipulating build expressions. |
| 1561 | @end menu |
| 1562 | |
| 1563 | @node Defining Packages |
| 1564 | @section Defining Packages |
| 1565 | |
| 1566 | The high-level interface to package definitions is implemented in the |
| 1567 | @code{(guix packages)} and @code{(guix build-system)} modules. As an |
| 1568 | example, the package definition, or @dfn{recipe}, for the GNU Hello |
| 1569 | package looks like this: |
| 1570 | |
| 1571 | @example |
| 1572 | (define-module (gnu packages hello) |
| 1573 | #:use-module (guix packages) |
| 1574 | #:use-module (guix download) |
| 1575 | #:use-module (guix build-system gnu) |
| 1576 | #:use-module (guix licenses)) |
| 1577 | |
| 1578 | (define-public hello |
| 1579 | (package |
| 1580 | (name "hello") |
| 1581 | (version "2.8") |
| 1582 | (source (origin |
| 1583 | (method url-fetch) |
| 1584 | (uri (string-append "mirror://gnu/hello/hello-" version |
| 1585 | ".tar.gz")) |
| 1586 | (sha256 |
| 1587 | (base32 "0wqd8sjmxfskrflaxywc7gqw7sfawrfvdxd9skxawzfgyy0pzdz6")))) |
| 1588 | (build-system gnu-build-system) |
| 1589 | (arguments `(#:configure-flags '("--enable-silent-rules"))) |
| 1590 | (inputs `(("gawk" ,gawk))) |
| 1591 | (synopsis "Hello, GNU world: An example GNU package") |
| 1592 | (description "Guess what GNU Hello prints!") |
| 1593 | (home-page "http://www.gnu.org/software/hello/") |
| 1594 | (license gpl3+))) |
| 1595 | @end example |
| 1596 | |
| 1597 | @noindent |
| 1598 | Without being a Scheme expert, the reader may have guessed the meaning |
| 1599 | of the various fields here. This expression binds variable @code{hello} |
| 1600 | to a @code{<package>} object, which is essentially a record |
| 1601 | (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}). |
| 1602 | This package object can be inspected using procedures found in the |
| 1603 | @code{(guix packages)} module; for instance, @code{(package-name hello)} |
| 1604 | returns---surprise!---@code{"hello"}. |
| 1605 | |
| 1606 | With luck, you may be able to import part or all of the definition of |
| 1607 | the package you are interested in from another repository, using the |
| 1608 | @code{guix import} command (@pxref{Invoking guix import}). |
| 1609 | |
| 1610 | In the example above, @var{hello} is defined into a module of its own, |
| 1611 | @code{(gnu packages hello)}. Technically, this is not strictly |
| 1612 | necessary, but it is convenient to do so: all the packages defined in |
| 1613 | modules under @code{(gnu packages @dots{})} are automatically known to |
| 1614 | the command-line tools (@pxref{Package Modules}). |
| 1615 | |
| 1616 | There are a few points worth noting in the above package definition: |
| 1617 | |
| 1618 | @itemize |
| 1619 | @item |
| 1620 | The @code{source} field of the package is an @code{<origin>} object. |
| 1621 | Here, the @code{url-fetch} method from @code{(guix download)} is used, |
| 1622 | meaning that the source is a file to be downloaded over FTP or HTTP. |
| 1623 | |
| 1624 | The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of |
| 1625 | the GNU mirrors defined in @code{(guix download)}. |
| 1626 | |
| 1627 | The @code{sha256} field specifies the expected SHA256 hash of the file |
| 1628 | being downloaded. It is mandatory, and allows Guix to check the |
| 1629 | integrity of the file. The @code{(base32 @dots{})} form introduces the |
| 1630 | base32 representation of the hash. You can obtain this information with |
| 1631 | @code{guix download} (@pxref{Invoking guix download}) and @code{guix |
| 1632 | hash} (@pxref{Invoking guix hash}). |
| 1633 | |
| 1634 | @cindex patches |
| 1635 | When needed, the @code{origin} form can also have a @code{patches} field |
| 1636 | listing patches to be applied, and a @code{snippet} field giving a |
| 1637 | Scheme expression to modify the source code. |
| 1638 | |
| 1639 | @item |
| 1640 | @cindex GNU Build System |
| 1641 | The @code{build-system} field specifies the procedure to build the |
| 1642 | package (@pxref{Build Systems}). Here, @var{gnu-build-system} |
| 1643 | represents the familiar GNU Build System, where packages may be |
| 1644 | configured, built, and installed with the usual @code{./configure && |
| 1645 | make && make check && make install} command sequence. |
| 1646 | |
| 1647 | @item |
| 1648 | The @code{arguments} field specifies options for the build system |
| 1649 | (@pxref{Build Systems}). Here it is interpreted by |
| 1650 | @var{gnu-build-system} as a request run @file{configure} with the |
| 1651 | @code{--enable-silent-rules} flag. |
| 1652 | |
| 1653 | @item |
| 1654 | The @code{inputs} field specifies inputs to the build process---i.e., |
| 1655 | build-time or run-time dependencies of the package. Here, we define an |
| 1656 | input called @code{"gawk"} whose value is that of the @var{gawk} |
| 1657 | variable; @var{gawk} is itself bound to a @code{<package>} object. |
| 1658 | |
| 1659 | Note that GCC, Coreutils, Bash, and other essential tools do not need to |
| 1660 | be specified as inputs here. Instead, @var{gnu-build-system} takes care |
| 1661 | of ensuring that they are present (@pxref{Build Systems}). |
| 1662 | |
| 1663 | However, any other dependencies need to be specified in the |
| 1664 | @code{inputs} field. Any dependency not specified here will simply be |
| 1665 | unavailable to the build process, possibly leading to a build failure. |
| 1666 | @end itemize |
| 1667 | |
| 1668 | Once a package definition is in place, the |
| 1669 | package may actually be built using the @code{guix build} command-line |
| 1670 | tool (@pxref{Invoking guix build}). @xref{Packaging Guidelines}, for |
| 1671 | more information on how to test package definitions, and |
| 1672 | @ref{Invoking guix lint}, for information on how to check a definition |
| 1673 | for style conformance. |
| 1674 | |
| 1675 | Eventually, updating the package definition to a new upstream version |
| 1676 | can be partly automated by the @command{guix refresh} command |
| 1677 | (@pxref{Invoking guix refresh}). |
| 1678 | |
| 1679 | Behind the scenes, a derivation corresponding to the @code{<package>} |
| 1680 | object is first computed by the @code{package-derivation} procedure. |
| 1681 | That derivation is stored in a @code{.drv} file under @file{/gnu/store}. |
| 1682 | The build actions it prescribes may then be realized by using the |
| 1683 | @code{build-derivations} procedure (@pxref{The Store}). |
| 1684 | |
| 1685 | @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}] |
| 1686 | Return the @code{<derivation>} object of @var{package} for @var{system} |
| 1687 | (@pxref{Derivations}). |
| 1688 | |
| 1689 | @var{package} must be a valid @code{<package>} object, and @var{system} |
| 1690 | must be a string denoting the target system type---e.g., |
| 1691 | @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store} |
| 1692 | must be a connection to the daemon, which operates on the store |
| 1693 | (@pxref{The Store}). |
| 1694 | @end deffn |
| 1695 | |
| 1696 | @noindent |
| 1697 | @cindex cross-compilation |
| 1698 | Similarly, it is possible to compute a derivation that cross-builds a |
| 1699 | package for some other system: |
| 1700 | |
| 1701 | @deffn {Scheme Procedure} package-cross-derivation @var{store} @ |
| 1702 | @var{package} @var{target} [@var{system}] |
| 1703 | Return the @code{<derivation>} object of @var{package} cross-built from |
| 1704 | @var{system} to @var{target}. |
| 1705 | |
| 1706 | @var{target} must be a valid GNU triplet denoting the target hardware |
| 1707 | and operating system, such as @code{"mips64el-linux-gnu"} |
| 1708 | (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU |
| 1709 | Configure and Build System}). |
| 1710 | @end deffn |
| 1711 | |
| 1712 | |
| 1713 | @node Build Systems |
| 1714 | @section Build Systems |
| 1715 | |
| 1716 | @cindex build system |
| 1717 | Each package definition specifies a @dfn{build system} and arguments for |
| 1718 | that build system (@pxref{Defining Packages}). This @code{build-system} |
| 1719 | field represents the build procedure of the package, as well implicit |
| 1720 | dependencies of that build procedure. |
| 1721 | |
| 1722 | Build systems are @code{<build-system>} objects. The interface to |
| 1723 | create and manipulate them is provided by the @code{(guix build-system)} |
| 1724 | module, and actual build systems are exported by specific modules. |
| 1725 | |
| 1726 | @cindex bag (low-level package representation) |
| 1727 | Under the hood, build systems first compile package objects to |
| 1728 | @dfn{bags}. A @dfn{bag} is like a package, but with less |
| 1729 | ornamentation---in other words, a bag is a lower-level representation of |
| 1730 | a package, which includes all the inputs of that package, including some |
| 1731 | that were implicitly added by the build system. This intermediate |
| 1732 | representation is then compiled to a derivation (@pxref{Derivations}). |
| 1733 | |
| 1734 | Build systems accept an optional list of @dfn{arguments}. In package |
| 1735 | definitions, these are passed @i{via} the @code{arguments} field |
| 1736 | (@pxref{Defining Packages}). They are typically keyword arguments |
| 1737 | (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU |
| 1738 | Guile Reference Manual}). The value of these arguments is usually |
| 1739 | evaluated in the @dfn{build stratum}---i.e., by a Guile process launched |
| 1740 | by the daemon (@pxref{Derivations}). |
| 1741 | |
| 1742 | The main build system is @var{gnu-build-system}, which implements the |
| 1743 | standard build procedure for GNU packages and many other packages. It |
| 1744 | is provided by the @code{(guix build-system gnu)} module. |
| 1745 | |
| 1746 | @defvr {Scheme Variable} gnu-build-system |
| 1747 | @var{gnu-build-system} represents the GNU Build System, and variants |
| 1748 | thereof (@pxref{Configuration, configuration and makefile conventions,, |
| 1749 | standards, GNU Coding Standards}). |
| 1750 | |
| 1751 | @cindex build phases |
| 1752 | In a nutshell, packages using it configured, built, and installed with |
| 1753 | the usual @code{./configure && make && make check && make install} |
| 1754 | command sequence. In practice, a few additional steps are often needed. |
| 1755 | All these steps are split up in separate @dfn{phases}, |
| 1756 | notably@footnote{Please see the @code{(guix build gnu-build-system)} |
| 1757 | modules for more details about the build phases.}: |
| 1758 | |
| 1759 | @table @code |
| 1760 | @item unpack |
| 1761 | Unpack the source tarball, and change the current directory to the |
| 1762 | extracted source tree. If the source is actually a directory, copy it |
| 1763 | to the build tree, and enter that directory. |
| 1764 | |
| 1765 | @item patch-source-shebangs |
| 1766 | Patch shebangs encountered in source files so they refer to the right |
| 1767 | store file names. For instance, this changes @code{#!/bin/sh} to |
| 1768 | @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}. |
| 1769 | |
| 1770 | @item configure |
| 1771 | Run the @file{configure} script with a number of default options, such |
| 1772 | as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified |
| 1773 | by the @code{#:configure-flags} argument. |
| 1774 | |
| 1775 | @item build |
| 1776 | Run @code{make} with the list of flags specified with |
| 1777 | @code{#:make-flags}. If the @code{#:parallel-builds?} argument is true |
| 1778 | (the default), build with @code{make -j}. |
| 1779 | |
| 1780 | @item check |
| 1781 | Run @code{make check}, or some other target specified with |
| 1782 | @code{#:test-target}, unless @code{#:tests? #f} is passed. If the |
| 1783 | @code{#:parallel-tests?} argument is true (the default), run @code{make |
| 1784 | check -j}. |
| 1785 | |
| 1786 | @item install |
| 1787 | Run @code{make install} with the flags listed in @code{#:make-flags}. |
| 1788 | |
| 1789 | @item patch-shebangs |
| 1790 | Patch shebangs on the installed executable files. |
| 1791 | |
| 1792 | @item strip |
| 1793 | Strip debugging symbols from ELF files (unless @code{#:strip-binaries?} |
| 1794 | is false), copying them to the @code{debug} output when available |
| 1795 | (@pxref{Installing Debugging Files}). |
| 1796 | @end table |
| 1797 | |
| 1798 | @vindex %standard-phases |
| 1799 | The build-side module @code{(guix build gnu-build-system)} defines |
| 1800 | @var{%standard-phases} as the default list of build phases. |
| 1801 | @var{%standard-phases} is a list of symbol/procedure pairs, where the |
| 1802 | procedure implements the actual phase. |
| 1803 | |
| 1804 | The list of phases used for a particular package can be changed with the |
| 1805 | @code{#:phases} parameter. For instance, passing: |
| 1806 | |
| 1807 | @example |
| 1808 | #:phases (alist-delete 'configure %standard-phases) |
| 1809 | @end example |
| 1810 | |
| 1811 | means that all the phases described above will be used, except the |
| 1812 | @code{configure} phase. |
| 1813 | |
| 1814 | In addition, this build system ensures that the ``standard'' environment |
| 1815 | for GNU packages is available. This includes tools such as GCC, libc, |
| 1816 | Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix |
| 1817 | build-system gnu)} module for a complete list.) We call these the |
| 1818 | @dfn{implicit inputs} of a package, because package definitions don't |
| 1819 | have to mention them. |
| 1820 | @end defvr |
| 1821 | |
| 1822 | Other @code{<build-system>} objects are defined to support other |
| 1823 | conventions and tools used by free software packages. They inherit most |
| 1824 | of @var{gnu-build-system}, and differ mainly in the set of inputs |
| 1825 | implicitly added to the build process, and in the list of phases |
| 1826 | executed. Some of these build systems are listed below. |
| 1827 | |
| 1828 | @defvr {Scheme Variable} cmake-build-system |
| 1829 | This variable is exported by @code{(guix build-system cmake)}. It |
| 1830 | implements the build procedure for packages using the |
| 1831 | @url{http://www.cmake.org, CMake build tool}. |
| 1832 | |
| 1833 | It automatically adds the @code{cmake} package to the set of inputs. |
| 1834 | Which package is used can be specified with the @code{#:cmake} |
| 1835 | parameter. |
| 1836 | |
| 1837 | The @code{#:configure-flags} parameter is taken as a list of flags |
| 1838 | passed to the @command{cmake} command. The @code{#:build-type} |
| 1839 | parameter specifies in abstract terms the flags passed to the compiler; |
| 1840 | it defaults to @code{"RelWithDebInfo"} (short for ``release mode with |
| 1841 | debugging information''), which roughly means that code is compiled with |
| 1842 | @code{-O2 -g}, as is the case for Autoconf-based packages by default. |
| 1843 | @end defvr |
| 1844 | |
| 1845 | @defvr {Scheme Variable} glib-or-gtk-build-system |
| 1846 | This variable is exported by @code{(guix build-system glib-or-gtk)}. It |
| 1847 | is intended for use with packages making use of GLib or GTK+. |
| 1848 | |
| 1849 | This build system adds the following two phases to the ones defined by |
| 1850 | @var{gnu-build-system}: |
| 1851 | |
| 1852 | @table @code |
| 1853 | @item glib-or-gtk-wrap |
| 1854 | The phase @code{glib-or-gtk-wrap} ensures that programs found under |
| 1855 | @file{bin/} are able to find GLib's ``schemas'' and |
| 1856 | @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+ |
| 1857 | modules}. This is achieved by wrapping the programs in launch scripts |
| 1858 | that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH} |
| 1859 | environment variables. |
| 1860 | |
| 1861 | It is possible to exclude specific package outputs from that wrapping |
| 1862 | process by listing their names in the |
| 1863 | @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful |
| 1864 | when an output is known not to contain any GLib or GTK+ binaries, and |
| 1865 | where wrapping would gratuitously add a dependency of that output on |
| 1866 | GLib and GTK+. |
| 1867 | |
| 1868 | @item glib-or-gtk-compile-schemas |
| 1869 | The phase @code{glib-or-gtk-compile-schemas} makes sure that all GLib's |
| 1870 | @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html, |
| 1871 | GSettings schemas} are compiled. Compilation is performed by the |
| 1872 | @command{glib-compile-schemas} program. It is provided by the package |
| 1873 | @code{glib:bin} which is automatically imported by the build system. |
| 1874 | The @code{glib} package providing @command{glib-compile-schemas} can be |
| 1875 | specified with the @code{#:glib} parameter. |
| 1876 | @end table |
| 1877 | |
| 1878 | Both phases are executed after the @code{install} phase. |
| 1879 | @end defvr |
| 1880 | |
| 1881 | @defvr {Scheme Variable} python-build-system |
| 1882 | This variable is exported by @code{(guix build-system python)}. It |
| 1883 | implements the more or less standard build procedure used by Python |
| 1884 | packages, which consists in running @code{python setup.py build} and |
| 1885 | then @code{python setup.py install --prefix=/gnu/store/@dots{}}. |
| 1886 | |
| 1887 | For packages that install stand-alone Python programs under @code{bin/}, |
| 1888 | it takes care of wrapping these programs so their @code{PYTHONPATH} |
| 1889 | environment variable points to all the Python libraries they depend on. |
| 1890 | |
| 1891 | Which Python package is used can be specified with the @code{#:python} |
| 1892 | parameter. |
| 1893 | @end defvr |
| 1894 | |
| 1895 | @defvr {Scheme Variable} perl-build-system |
| 1896 | This variable is exported by @code{(guix build-system perl)}. It |
| 1897 | implements the standard build procedure for Perl packages, which |
| 1898 | consists in running @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, |
| 1899 | followed by @code{make} and @code{make install}. |
| 1900 | |
| 1901 | The initial @code{perl Makefile.PL} invocation passes flags specified by |
| 1902 | the @code{#:make-maker-flags} parameter. |
| 1903 | |
| 1904 | Which Perl package is used can be specified with @code{#:perl}. |
| 1905 | @end defvr |
| 1906 | |
| 1907 | @defvr {Scheme Variable} ruby-build-system |
| 1908 | This variable is exported by @code{(guix build-system ruby)}. It |
| 1909 | implements the RubyGems build procedure used by Ruby packages, which |
| 1910 | involves running @code{gem build} followed by @code{gem install}. |
| 1911 | |
| 1912 | Which Ruby package is used can be specified with the @code{#:ruby} |
| 1913 | parameter. |
| 1914 | @end defvr |
| 1915 | |
| 1916 | @defvr {Scheme Variable} waf-build-system |
| 1917 | This variable is exported by @code{(guix build-system waf)}. It |
| 1918 | implements a build procedure around the @code{waf} script. The common |
| 1919 | phases---@code{configure}, @code{build}, and @code{install}---are |
| 1920 | implemented by passing their names as arguments to the @code{waf} |
| 1921 | script. |
| 1922 | |
| 1923 | The @code{waf} script is executed by the Python interpreter. Which |
| 1924 | Python package is used to run the script can be specified with the |
| 1925 | @code{#:python} parameter. |
| 1926 | @end defvr |
| 1927 | |
| 1928 | Lastly, for packages that do not need anything as sophisticated, a |
| 1929 | ``trivial'' build system is provided. It is trivial in the sense that |
| 1930 | it provides basically no support: it does not pull any implicit inputs, |
| 1931 | and does not have a notion of build phases. |
| 1932 | |
| 1933 | @defvr {Scheme Variable} trivial-build-system |
| 1934 | This variable is exported by @code{(guix build-system trivial)}. |
| 1935 | |
| 1936 | This build system requires a @code{#:builder} argument. This argument |
| 1937 | must be a Scheme expression that builds the package's output(s)---as |
| 1938 | with @code{build-expression->derivation} (@pxref{Derivations, |
| 1939 | @code{build-expression->derivation}}). |
| 1940 | @end defvr |
| 1941 | |
| 1942 | @node The Store |
| 1943 | @section The Store |
| 1944 | |
| 1945 | @cindex store |
| 1946 | @cindex store paths |
| 1947 | |
| 1948 | Conceptually, the @dfn{store} is where derivations that have been |
| 1949 | successfully built are stored---by default, under @file{/gnu/store}. |
| 1950 | Sub-directories in the store are referred to as @dfn{store paths}. The |
| 1951 | store has an associated database that contains information such has the |
| 1952 | store paths referred to by each store path, and the list of @emph{valid} |
| 1953 | store paths---paths that result from a successful build. |
| 1954 | |
| 1955 | The store is always accessed by the daemon on behalf of its clients |
| 1956 | (@pxref{Invoking guix-daemon}). To manipulate the store, clients |
| 1957 | connect to the daemon over a Unix-domain socket, send it requests, and |
| 1958 | read the result---these are remote procedure calls, or RPCs. |
| 1959 | |
| 1960 | The @code{(guix store)} module provides procedures to connect to the |
| 1961 | daemon, and to perform RPCs. These are described below. |
| 1962 | |
| 1963 | @deffn {Scheme Procedure} open-connection [@var{file}] [#:reserve-space? #t] |
| 1964 | Connect to the daemon over the Unix-domain socket at @var{file}. When |
| 1965 | @var{reserve-space?} is true, instruct it to reserve a little bit of |
| 1966 | extra space on the file system so that the garbage collector can still |
| 1967 | operate, should the disk become full. Return a server object. |
| 1968 | |
| 1969 | @var{file} defaults to @var{%default-socket-path}, which is the normal |
| 1970 | location given the options that were passed to @command{configure}. |
| 1971 | @end deffn |
| 1972 | |
| 1973 | @deffn {Scheme Procedure} close-connection @var{server} |
| 1974 | Close the connection to @var{server}. |
| 1975 | @end deffn |
| 1976 | |
| 1977 | @defvr {Scheme Variable} current-build-output-port |
| 1978 | This variable is bound to a SRFI-39 parameter, which refers to the port |
| 1979 | where build and error logs sent by the daemon should be written. |
| 1980 | @end defvr |
| 1981 | |
| 1982 | Procedures that make RPCs all take a server object as their first |
| 1983 | argument. |
| 1984 | |
| 1985 | @deffn {Scheme Procedure} valid-path? @var{server} @var{path} |
| 1986 | Return @code{#t} when @var{path} is a valid store path. |
| 1987 | @end deffn |
| 1988 | |
| 1989 | @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}] |
| 1990 | Add @var{text} under file @var{name} in the store, and return its store |
| 1991 | path. @var{references} is the list of store paths referred to by the |
| 1992 | resulting store path. |
| 1993 | @end deffn |
| 1994 | |
| 1995 | @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations} |
| 1996 | Build @var{derivations} (a list of @code{<derivation>} objects or |
| 1997 | derivation paths), and return when the worker is done building them. |
| 1998 | Return @code{#t} on success. |
| 1999 | @end deffn |
| 2000 | |
| 2001 | Note that the @code{(guix monads)} module provides a monad as well as |
| 2002 | monadic versions of the above procedures, with the goal of making it |
| 2003 | more convenient to work with code that accesses the store (@pxref{The |
| 2004 | Store Monad}). |
| 2005 | |
| 2006 | @c FIXME |
| 2007 | @i{This section is currently incomplete.} |
| 2008 | |
| 2009 | @node Derivations |
| 2010 | @section Derivations |
| 2011 | |
| 2012 | @cindex derivations |
| 2013 | Low-level build actions and the environment in which they are performed |
| 2014 | are represented by @dfn{derivations}. A derivation contain the |
| 2015 | following pieces of information: |
| 2016 | |
| 2017 | @itemize |
| 2018 | @item |
| 2019 | The outputs of the derivation---derivations produce at least one file or |
| 2020 | directory in the store, but may produce more. |
| 2021 | |
| 2022 | @item |
| 2023 | The inputs of the derivations, which may be other derivations or plain |
| 2024 | files in the store (patches, build scripts, etc.) |
| 2025 | |
| 2026 | @item |
| 2027 | The system type targeted by the derivation---e.g., @code{x86_64-linux}. |
| 2028 | |
| 2029 | @item |
| 2030 | The file name of a build script in the store, along with the arguments |
| 2031 | to be passed. |
| 2032 | |
| 2033 | @item |
| 2034 | A list of environment variables to be defined. |
| 2035 | |
| 2036 | @end itemize |
| 2037 | |
| 2038 | @cindex derivation path |
| 2039 | Derivations allow clients of the daemon to communicate build actions to |
| 2040 | the store. They exist in two forms: as an in-memory representation, |
| 2041 | both on the client- and daemon-side, and as files in the store whose |
| 2042 | name end in @code{.drv}---these files are referred to as @dfn{derivation |
| 2043 | paths}. Derivations paths can be passed to the @code{build-derivations} |
| 2044 | procedure to perform the build actions they prescribe (@pxref{The |
| 2045 | Store}). |
| 2046 | |
| 2047 | The @code{(guix derivations)} module provides a representation of |
| 2048 | derivations as Scheme objects, along with procedures to create and |
| 2049 | otherwise manipulate derivations. The lowest-level primitive to create |
| 2050 | a derivation is the @code{derivation} procedure: |
| 2051 | |
| 2052 | @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @ |
| 2053 | @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @ |
| 2054 | [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @ |
| 2055 | [#:system (%current-system)] [#:references-graphs #f] @ |
| 2056 | [#:allowed-references #f] [#:local-build? #f] |
| 2057 | Build a derivation with the given arguments, and return the resulting |
| 2058 | @code{<derivation>} object. |
| 2059 | |
| 2060 | When @var{hash} and @var{hash-algo} are given, a |
| 2061 | @dfn{fixed-output derivation} is created---i.e., one whose result is |
| 2062 | known in advance, such as a file download. If, in addition, |
| 2063 | @var{recursive?} is true, then that fixed output may be an executable |
| 2064 | file or a directory and @var{hash} must be the hash of an archive |
| 2065 | containing this output. |
| 2066 | |
| 2067 | When @var{references-graphs} is true, it must be a list of file |
| 2068 | name/store path pairs. In that case, the reference graph of each store |
| 2069 | path is exported in the build environment in the corresponding file, in |
| 2070 | a simple text format. |
| 2071 | |
| 2072 | When @var{allowed-references} is true, it must be a list of store items |
| 2073 | or outputs that the derivation's output may refer to. |
| 2074 | |
| 2075 | When @var{local-build?} is true, declare that the derivation is not a |
| 2076 | good candidate for offloading and should rather be built locally |
| 2077 | (@pxref{Daemon Offload Setup}). This is the case for small derivations |
| 2078 | where the costs of data transfers would outweigh the benefits. |
| 2079 | @end deffn |
| 2080 | |
| 2081 | @noindent |
| 2082 | Here's an example with a shell script as its builder, assuming |
| 2083 | @var{store} is an open connection to the daemon, and @var{bash} points |
| 2084 | to a Bash executable in the store: |
| 2085 | |
| 2086 | @lisp |
| 2087 | (use-modules (guix utils) |
| 2088 | (guix store) |
| 2089 | (guix derivations)) |
| 2090 | |
| 2091 | (let ((builder ; add the Bash script to the store |
| 2092 | (add-text-to-store store "my-builder.sh" |
| 2093 | "echo hello world > $out\n" '()))) |
| 2094 | (derivation store "foo" |
| 2095 | bash `("-e" ,builder) |
| 2096 | #:inputs `((,bash) (,builder)) |
| 2097 | #:env-vars '(("HOME" . "/homeless")))) |
| 2098 | @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo> |
| 2099 | @end lisp |
| 2100 | |
| 2101 | As can be guessed, this primitive is cumbersome to use directly. A |
| 2102 | better approach is to write build scripts in Scheme, of course! The |
| 2103 | best course of action for that is to write the build code as a |
| 2104 | ``G-expression'', and to pass it to @code{gexp->derivation}. For more |
| 2105 | information, @pxref{G-Expressions}. |
| 2106 | |
| 2107 | Once upon a time, @code{gexp->derivation} did not exist and constructing |
| 2108 | derivations with build code written in Scheme was achieved with |
| 2109 | @code{build-expression->derivation}, documented below. This procedure |
| 2110 | is now deprecated in favor of the much nicer @code{gexp->derivation}. |
| 2111 | |
| 2112 | @deffn {Scheme Procedure} build-expression->derivation @var{store} @ |
| 2113 | @var{name} @var{exp} @ |
| 2114 | [#:system (%current-system)] [#:inputs '()] @ |
| 2115 | [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @ |
| 2116 | [#:recursive? #f] [#:env-vars '()] [#:modules '()] @ |
| 2117 | [#:references-graphs #f] [#:allowed-references #f] @ |
| 2118 | [#:local-build? #f] [#:guile-for-build #f] |
| 2119 | Return a derivation that executes Scheme expression @var{exp} as a |
| 2120 | builder for derivation @var{name}. @var{inputs} must be a list of |
| 2121 | @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted, |
| 2122 | @code{"out"} is assumed. @var{modules} is a list of names of Guile |
| 2123 | modules from the current search path to be copied in the store, |
| 2124 | compiled, and made available in the load path during the execution of |
| 2125 | @var{exp}---e.g., @code{((guix build utils) (guix build |
| 2126 | gnu-build-system))}. |
| 2127 | |
| 2128 | @var{exp} is evaluated in an environment where @code{%outputs} is bound |
| 2129 | to a list of output/path pairs, and where @code{%build-inputs} is bound |
| 2130 | to a list of string/output-path pairs made from @var{inputs}. |
| 2131 | Optionally, @var{env-vars} is a list of string pairs specifying the name |
| 2132 | and value of environment variables visible to the builder. The builder |
| 2133 | terminates by passing the result of @var{exp} to @code{exit}; thus, when |
| 2134 | @var{exp} returns @code{#f}, the build is considered to have failed. |
| 2135 | |
| 2136 | @var{exp} is built using @var{guile-for-build} (a derivation). When |
| 2137 | @var{guile-for-build} is omitted or is @code{#f}, the value of the |
| 2138 | @code{%guile-for-build} fluid is used instead. |
| 2139 | |
| 2140 | See the @code{derivation} procedure for the meaning of |
| 2141 | @var{references-graphs}, @var{allowed-references}, and @var{local-build?}. |
| 2142 | @end deffn |
| 2143 | |
| 2144 | @noindent |
| 2145 | Here's an example of a single-output derivation that creates a directory |
| 2146 | containing one file: |
| 2147 | |
| 2148 | @lisp |
| 2149 | (let ((builder '(let ((out (assoc-ref %outputs "out"))) |
| 2150 | (mkdir out) ; create /gnu/store/@dots{}-goo |
| 2151 | (call-with-output-file (string-append out "/test") |
| 2152 | (lambda (p) |
| 2153 | (display '(hello guix) p)))))) |
| 2154 | (build-expression->derivation store "goo" builder)) |
| 2155 | |
| 2156 | @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}> |
| 2157 | @end lisp |
| 2158 | |
| 2159 | |
| 2160 | @node The Store Monad |
| 2161 | @section The Store Monad |
| 2162 | |
| 2163 | @cindex monad |
| 2164 | |
| 2165 | The procedures that operate on the store described in the previous |
| 2166 | sections all take an open connection to the build daemon as their first |
| 2167 | argument. Although the underlying model is functional, they either have |
| 2168 | side effects or depend on the current state of the store. |
| 2169 | |
| 2170 | The former is inconvenient: the connection to the build daemon has to be |
| 2171 | carried around in all those functions, making it impossible to compose |
| 2172 | functions that do not take that parameter with functions that do. The |
| 2173 | latter can be problematic: since store operations have side effects |
| 2174 | and/or depend on external state, they have to be properly sequenced. |
| 2175 | |
| 2176 | @cindex monadic values |
| 2177 | @cindex monadic functions |
| 2178 | This is where the @code{(guix monads)} module comes in. This module |
| 2179 | provides a framework for working with @dfn{monads}, and a particularly |
| 2180 | useful monad for our uses, the @dfn{store monad}. Monads are a |
| 2181 | construct that allows two things: associating ``context'' with values |
| 2182 | (in our case, the context is the store), and building sequences of |
| 2183 | computations (here computations include accesses to the store.) Values |
| 2184 | in a monad---values that carry this additional context---are called |
| 2185 | @dfn{monadic values}; procedures that return such values are called |
| 2186 | @dfn{monadic procedures}. |
| 2187 | |
| 2188 | Consider this ``normal'' procedure: |
| 2189 | |
| 2190 | @example |
| 2191 | (define (sh-symlink store) |
| 2192 | ;; Return a derivation that symlinks the 'bash' executable. |
| 2193 | (let* ((drv (package-derivation store bash)) |
| 2194 | (out (derivation->output-path drv)) |
| 2195 | (sh (string-append out "/bin/bash"))) |
| 2196 | (build-expression->derivation store "sh" |
| 2197 | `(symlink ,sh %output)))) |
| 2198 | @end example |
| 2199 | |
| 2200 | Using @code{(guix monads)}, it may be rewritten as a monadic function: |
| 2201 | |
| 2202 | @c FIXME: Find a better example, one that uses 'mlet'. |
| 2203 | @example |
| 2204 | (define (sh-symlink) |
| 2205 | ;; Same, but return a monadic value. |
| 2206 | (gexp->derivation "sh" |
| 2207 | #~(symlink (string-append #$bash "/bin/bash") #$output))) |
| 2208 | @end example |
| 2209 | |
| 2210 | There are two things to note in the second version: the @code{store} |
| 2211 | parameter is now implicit, and the monadic value returned by |
| 2212 | @code{package-file}---a wrapper around @code{package-derivation} and |
| 2213 | @code{derivation->output-path}---is @dfn{bound} using @code{mlet} |
| 2214 | instead of plain @code{let}. |
| 2215 | |
| 2216 | Calling the monadic @code{profile.sh} has no effect. To get the desired |
| 2217 | effect, one must use @code{run-with-store}: |
| 2218 | |
| 2219 | @example |
| 2220 | (run-with-store (open-connection) (profile.sh)) |
| 2221 | @result{} /gnu/store/...-profile.sh |
| 2222 | @end example |
| 2223 | |
| 2224 | Note that the @code{(guix monad-repl)} module extends Guile's REPL with |
| 2225 | new ``meta-commands'' to make it easier to deal with monadic procedures: |
| 2226 | @code{run-in-store}, and @code{enter-store-monad}. The former, is used |
| 2227 | to ``run'' a single monadic value through the store: |
| 2228 | |
| 2229 | @example |
| 2230 | scheme@@(guile-user)> ,run-in-store (package->derivation hello) |
| 2231 | $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}> |
| 2232 | @end example |
| 2233 | |
| 2234 | The latter enters a recursive REPL, where all the return values are |
| 2235 | automatically run through the store: |
| 2236 | |
| 2237 | @example |
| 2238 | scheme@@(guile-user)> ,enter-store-monad |
| 2239 | store-monad@@(guile-user) [1]> (package->derivation hello) |
| 2240 | $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}> |
| 2241 | store-monad@@(guile-user) [1]> (text-file "foo" "Hello!") |
| 2242 | $3 = "/gnu/store/@dots{}-foo" |
| 2243 | store-monad@@(guile-user) [1]> ,q |
| 2244 | scheme@@(guile-user)> |
| 2245 | @end example |
| 2246 | |
| 2247 | @noindent |
| 2248 | Note that non-monadic values cannot be returned in the |
| 2249 | @code{store-monad} REPL. |
| 2250 | |
| 2251 | The main syntactic forms to deal with monads in general are provided by |
| 2252 | the @code{(guix monads)} module and are described below. |
| 2253 | |
| 2254 | @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ... |
| 2255 | Evaluate any @code{>>=} or @code{return} forms in @var{body} as being |
| 2256 | in @var{monad}. |
| 2257 | @end deffn |
| 2258 | |
| 2259 | @deffn {Scheme Syntax} return @var{val} |
| 2260 | Return a monadic value that encapsulates @var{val}. |
| 2261 | @end deffn |
| 2262 | |
| 2263 | @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} |
| 2264 | @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic |
| 2265 | procedure @var{mproc}@footnote{This operation is commonly referred to as |
| 2266 | ``bind'', but that name denotes an unrelated procedure in Guile. Thus |
| 2267 | we use this somewhat cryptic symbol inherited from the Haskell |
| 2268 | language.}. |
| 2269 | @end deffn |
| 2270 | |
| 2271 | @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @ |
| 2272 | @var{body} ... |
| 2273 | @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @ |
| 2274 | @var{body} ... |
| 2275 | Bind the variables @var{var} to the monadic values @var{mval} in |
| 2276 | @var{body}. The form (@var{var} -> @var{val}) binds @var{var} to the |
| 2277 | ``normal'' value @var{val}, as per @code{let}. |
| 2278 | |
| 2279 | @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let} |
| 2280 | (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}). |
| 2281 | @end deffn |
| 2282 | |
| 2283 | @deffn {Scheme System} mbegin @var{monad} @var{mexp} ... |
| 2284 | Bind @var{mexp} and the following monadic expressions in sequence, |
| 2285 | returning the result of the last expression. |
| 2286 | |
| 2287 | This is akin to @code{mlet}, except that the return values of the |
| 2288 | monadic expressions are ignored. In that sense, it is analogous to |
| 2289 | @code{begin}, but applied to monadic expressions. |
| 2290 | @end deffn |
| 2291 | |
| 2292 | @cindex state monad |
| 2293 | The @code{(guix monads)} module provides the @dfn{state monad}, which |
| 2294 | allows an additional value---the state---to be @emph{threaded} through |
| 2295 | monadic procedure calls. |
| 2296 | |
| 2297 | @defvr {Scheme Variable} %state-monad |
| 2298 | The state monad. Procedures in the state monad can access and change |
| 2299 | the state that is threaded. |
| 2300 | |
| 2301 | Consider the example below. The @code{square} procedure returns a value |
| 2302 | in the state monad. It returns the square of its argument, but also |
| 2303 | increments the current state value: |
| 2304 | |
| 2305 | @example |
| 2306 | (define (square x) |
| 2307 | (mlet %state-monad ((count (current-state))) |
| 2308 | (mbegin %state-monad |
| 2309 | (set-current-state (+ 1 count)) |
| 2310 | (return (* x x))))) |
| 2311 | |
| 2312 | (run-with-state (sequence %state-monad (map square (iota 3))) 0) |
| 2313 | @result{} (0 1 4) |
| 2314 | @result{} 3 |
| 2315 | @end example |
| 2316 | |
| 2317 | When ``run'' through @var{%state-monad}, we obtain that additional state |
| 2318 | value, which is the number of @code{square} calls. |
| 2319 | @end defvr |
| 2320 | |
| 2321 | @deffn {Monadic Procedure} current-state |
| 2322 | Return the current state as a monadic value. |
| 2323 | @end deffn |
| 2324 | |
| 2325 | @deffn {Monadic Procedure} set-current-state @var{value} |
| 2326 | Set the current state to @var{value} and return the previous state as a |
| 2327 | monadic value. |
| 2328 | @end deffn |
| 2329 | |
| 2330 | @deffn {Monadic Procedure} state-push @var{value} |
| 2331 | Push @var{value} to the current state, which is assumed to be a list, |
| 2332 | and return the previous state as a monadic value. |
| 2333 | @end deffn |
| 2334 | |
| 2335 | @deffn {Monadic Procedure} state-pop |
| 2336 | Pop a value from the current state and return it as a monadic value. |
| 2337 | The state is assumed to be a list. |
| 2338 | @end deffn |
| 2339 | |
| 2340 | @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}] |
| 2341 | Run monadic value @var{mval} starting with @var{state} as the initial |
| 2342 | state. Return two values: the resulting value, and the resulting state. |
| 2343 | @end deffn |
| 2344 | |
| 2345 | The main interface to the store monad, provided by the @code{(guix |
| 2346 | store)} module, is as follows. |
| 2347 | |
| 2348 | @defvr {Scheme Variable} %store-monad |
| 2349 | The store monad---an alias for @var{%state-monad}. |
| 2350 | |
| 2351 | Values in the store monad encapsulate accesses to the store. When its |
| 2352 | effect is needed, a value of the store monad must be ``evaluated'' by |
| 2353 | passing it to the @code{run-with-store} procedure (see below.) |
| 2354 | @end defvr |
| 2355 | |
| 2356 | @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)] |
| 2357 | Run @var{mval}, a monadic value in the store monad, in @var{store}, an |
| 2358 | open store connection. |
| 2359 | @end deffn |
| 2360 | |
| 2361 | @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}] |
| 2362 | Return as a monadic value the absolute file name in the store of the file |
| 2363 | containing @var{text}, a string. @var{references} is a list of store items that the |
| 2364 | resulting text file refers to; it defaults to the empty list. |
| 2365 | @end deffn |
| 2366 | |
| 2367 | @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @ |
| 2368 | [#:recursive? #t] |
| 2369 | Return the name of @var{file} once interned in the store. Use |
| 2370 | @var{name} as its store name, or the basename of @var{file} if |
| 2371 | @var{name} is omitted. |
| 2372 | |
| 2373 | When @var{recursive?} is true, the contents of @var{file} are added |
| 2374 | recursively; if @var{file} designates a flat file and @var{recursive?} |
| 2375 | is true, its contents are added, and its permission bits are kept. |
| 2376 | |
| 2377 | The example below adds a file to the store, under two different names: |
| 2378 | |
| 2379 | @example |
| 2380 | (run-with-store (open-connection) |
| 2381 | (mlet %store-monad ((a (interned-file "README")) |
| 2382 | (b (interned-file "README" "LEGU-MIN"))) |
| 2383 | (return (list a b)))) |
| 2384 | |
| 2385 | @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN") |
| 2386 | @end example |
| 2387 | |
| 2388 | @end deffn |
| 2389 | |
| 2390 | The @code{(guix packages)} module exports the following package-related |
| 2391 | monadic procedures: |
| 2392 | |
| 2393 | @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @ |
| 2394 | [#:system (%current-system)] [#:target #f] @ |
| 2395 | [#:output "out"] Return as a monadic |
| 2396 | value in the absolute file name of @var{file} within the @var{output} |
| 2397 | directory of @var{package}. When @var{file} is omitted, return the name |
| 2398 | of the @var{output} directory of @var{package}. When @var{target} is |
| 2399 | true, use it as a cross-compilation target triplet. |
| 2400 | @end deffn |
| 2401 | |
| 2402 | @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}] |
| 2403 | @deffnx {Monadic Procedure} package->cross-derivation @var{package} @ |
| 2404 | @var{target} [@var{system}] |
| 2405 | Monadic version of @code{package-derivation} and |
| 2406 | @code{package-cross-derivation} (@pxref{Defining Packages}). |
| 2407 | @end deffn |
| 2408 | |
| 2409 | |
| 2410 | @node G-Expressions |
| 2411 | @section G-Expressions |
| 2412 | |
| 2413 | @cindex G-expression |
| 2414 | @cindex build code quoting |
| 2415 | So we have ``derivations'', which represent a sequence of build actions |
| 2416 | to be performed to produce an item in the store (@pxref{Derivations}). |
| 2417 | Those build actions are performed when asking the daemon to actually |
| 2418 | build the derivations; they are run by the daemon in a container |
| 2419 | (@pxref{Invoking guix-daemon}). |
| 2420 | |
| 2421 | @cindex strata of code |
| 2422 | It should come as no surprise that we like to write those build actions |
| 2423 | in Scheme. When we do that, we end up with two @dfn{strata} of Scheme |
| 2424 | code@footnote{The term @dfn{stratum} in this context was coined by |
| 2425 | Manuel Serrano et al.@: in the context of their work on Hop. Oleg |
| 2426 | Kiselyov, who has written insightful |
| 2427 | @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code |
| 2428 | on this topic}, refers to this kind of code generation as |
| 2429 | @dfn{staging}.}: the ``host code''---code that defines packages, talks |
| 2430 | to the daemon, etc.---and the ``build code''---code that actually |
| 2431 | performs build actions, such as making directories, invoking |
| 2432 | @command{make}, etc. |
| 2433 | |
| 2434 | To describe a derivation and its build actions, one typically needs to |
| 2435 | embed build code inside host code. It boils down to manipulating build |
| 2436 | code as data, and Scheme's homoiconicity---code has a direct |
| 2437 | representation as data---comes in handy for that. But we need more than |
| 2438 | Scheme's normal @code{quasiquote} mechanism to construct build |
| 2439 | expressions. |
| 2440 | |
| 2441 | The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of |
| 2442 | S-expressions adapted to build expressions. G-expressions, or |
| 2443 | @dfn{gexps}, consist essentially in three syntactic forms: @code{gexp}, |
| 2444 | @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~}, |
| 2445 | @code{#$}, and @code{#$@@}), which are comparable respectively to |
| 2446 | @code{quasiquote}, @code{unquote}, and @code{unquote-splicing} |
| 2447 | (@pxref{Expression Syntax, @code{quasiquote},, guile, GNU Guile |
| 2448 | Reference Manual}). However, there are major differences: |
| 2449 | |
| 2450 | @itemize |
| 2451 | @item |
| 2452 | Gexps are meant to be written to a file and run or manipulated by other |
| 2453 | processes. |
| 2454 | |
| 2455 | @item |
| 2456 | When a package or derivation is unquoted inside a gexp, the result is as |
| 2457 | if its output file name had been introduced. |
| 2458 | |
| 2459 | @item |
| 2460 | Gexps carry information about the packages or derivations they refer to, |
| 2461 | and these dependencies are automatically added as inputs to the build |
| 2462 | processes that use them. |
| 2463 | @end itemize |
| 2464 | |
| 2465 | To illustrate the idea, here is an example of a gexp: |
| 2466 | |
| 2467 | @example |
| 2468 | (define build-exp |
| 2469 | #~(begin |
| 2470 | (mkdir #$output) |
| 2471 | (chdir #$output) |
| 2472 | (symlink (string-append #$coreutils "/bin/ls") |
| 2473 | "list-files"))) |
| 2474 | @end example |
| 2475 | |
| 2476 | This gexp can be passed to @code{gexp->derivation}; we obtain a |
| 2477 | derivation that builds a directory containing exactly one symlink to |
| 2478 | @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}: |
| 2479 | |
| 2480 | @example |
| 2481 | (gexp->derivation "the-thing" build-exp) |
| 2482 | @end example |
| 2483 | |
| 2484 | As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is |
| 2485 | substituted to the reference to the @var{coreutils} package in the |
| 2486 | actual build code, and @var{coreutils} is automatically made an input to |
| 2487 | the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp |
| 2488 | output)}) is replaced by a string containing the derivation's output |
| 2489 | directory name. |
| 2490 | |
| 2491 | @cindex cross compilation |
| 2492 | In a cross-compilation context, it is useful to distinguish between |
| 2493 | references to the @emph{native} build of a package---that can run on the |
| 2494 | host---versus references to cross builds of a package. To that end, the |
| 2495 | @code{#+} plays the same role as @code{#$}, but is a reference to a |
| 2496 | native package build: |
| 2497 | |
| 2498 | @example |
| 2499 | (gexp->derivation "vi" |
| 2500 | #~(begin |
| 2501 | (mkdir #$output) |
| 2502 | (system* (string-append #+coreutils "/bin/ln") |
| 2503 | "-s" |
| 2504 | (string-append #$emacs "/bin/emacs") |
| 2505 | (string-append #$output "/bin/vi"))) |
| 2506 | #:target "mips64el-linux") |
| 2507 | @end example |
| 2508 | |
| 2509 | @noindent |
| 2510 | In the example above, the native build of @var{coreutils} is used, so |
| 2511 | that @command{ln} can actually run on the host; but then the |
| 2512 | cross-compiled build of @var{emacs} is referenced. |
| 2513 | |
| 2514 | The syntactic form to construct gexps is summarized below. |
| 2515 | |
| 2516 | @deffn {Scheme Syntax} #~@var{exp} |
| 2517 | @deffnx {Scheme Syntax} (gexp @var{exp}) |
| 2518 | Return a G-expression containing @var{exp}. @var{exp} may contain one |
| 2519 | or more of the following forms: |
| 2520 | |
| 2521 | @table @code |
| 2522 | @item #$@var{obj} |
| 2523 | @itemx (ungexp @var{obj}) |
| 2524 | Introduce a reference to @var{obj}. @var{obj} may be a package or a |
| 2525 | derivation, in which case the @code{ungexp} form is replaced by its |
| 2526 | output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}. |
| 2527 | |
| 2528 | If @var{obj} is a list, it is traversed and any package or derivation |
| 2529 | references are substituted similarly. |
| 2530 | |
| 2531 | If @var{obj} is another gexp, its contents are inserted and its |
| 2532 | dependencies are added to those of the containing gexp. |
| 2533 | |
| 2534 | If @var{obj} is another kind of object, it is inserted as is. |
| 2535 | |
| 2536 | @item #$@var{package-or-derivation}:@var{output} |
| 2537 | @itemx (ungexp @var{package-or-derivation} @var{output}) |
| 2538 | This is like the form above, but referring explicitly to the |
| 2539 | @var{output} of @var{package-or-derivation}---this is useful when |
| 2540 | @var{package-or-derivation} produces multiple outputs (@pxref{Packages |
| 2541 | with Multiple Outputs}). |
| 2542 | |
| 2543 | @item #+@var{obj} |
| 2544 | @itemx #+@var{obj}:output |
| 2545 | @itemx (ungexp-native @var{obj}) |
| 2546 | @itemx (ungexp-native @var{obj} @var{output}) |
| 2547 | Same as @code{ungexp}, but produces a reference to the @emph{native} |
| 2548 | build of @var{obj} when used in a cross compilation context. |
| 2549 | |
| 2550 | @item #$output[:@var{output}] |
| 2551 | @itemx (ungexp output [@var{output}]) |
| 2552 | Insert a reference to derivation output @var{output}, or to the main |
| 2553 | output when @var{output} is omitted. |
| 2554 | |
| 2555 | This only makes sense for gexps passed to @code{gexp->derivation}. |
| 2556 | |
| 2557 | @item #$@@@var{lst} |
| 2558 | @itemx (ungexp-splicing @var{lst}) |
| 2559 | Like the above, but splices the contents of @var{lst} inside the |
| 2560 | containing list. |
| 2561 | |
| 2562 | @item #+@@@var{lst} |
| 2563 | @itemx (ungexp-native-splicing @var{lst}) |
| 2564 | Like the above, but refers to native builds of the objects listed in |
| 2565 | @var{lst}. |
| 2566 | |
| 2567 | @end table |
| 2568 | |
| 2569 | G-expressions created by @code{gexp} or @code{#~} are run-time objects |
| 2570 | of the @code{gexp?} type (see below.) |
| 2571 | @end deffn |
| 2572 | |
| 2573 | @deffn {Scheme Procedure} gexp? @var{obj} |
| 2574 | Return @code{#t} if @var{obj} is a G-expression. |
| 2575 | @end deffn |
| 2576 | |
| 2577 | G-expressions are meant to be written to disk, either as code building |
| 2578 | some derivation, or as plain files in the store. The monadic procedures |
| 2579 | below allow you to do that (@pxref{The Store Monad}, for more |
| 2580 | information about monads.) |
| 2581 | |
| 2582 | @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @ |
| 2583 | [#:system (%current-system)] [#:target #f] [#:inputs '()] @ |
| 2584 | [#:hash #f] [#:hash-algo #f] @ |
| 2585 | [#:recursive? #f] [#:env-vars '()] [#:modules '()] @ |
| 2586 | [#:module-path @var{%load-path}] @ |
| 2587 | [#:references-graphs #f] [#:allowed-references #f] @ |
| 2588 | [#:local-build? #f] [#:guile-for-build #f] |
| 2589 | Return a derivation @var{name} that runs @var{exp} (a gexp) with |
| 2590 | @var{guile-for-build} (a derivation) on @var{system}. When @var{target} |
| 2591 | is true, it is used as the cross-compilation target triplet for packages |
| 2592 | referred to by @var{exp}. |
| 2593 | |
| 2594 | Make @var{modules} available in the evaluation context of @var{EXP}; |
| 2595 | @var{MODULES} is a list of names of Guile modules searched in |
| 2596 | @var{MODULE-PATH} to be copied in the store, compiled, and made available in |
| 2597 | the load path during the execution of @var{exp}---e.g., @code{((guix |
| 2598 | build utils) (guix build gnu-build-system))}. |
| 2599 | |
| 2600 | When @var{references-graphs} is true, it must be a list of tuples of one of the |
| 2601 | following forms: |
| 2602 | |
| 2603 | @example |
| 2604 | (@var{file-name} @var{package}) |
| 2605 | (@var{file-name} @var{package} @var{output}) |
| 2606 | (@var{file-name} @var{derivation}) |
| 2607 | (@var{file-name} @var{derivation} @var{output}) |
| 2608 | (@var{file-name} @var{store-item}) |
| 2609 | @end example |
| 2610 | |
| 2611 | The right-hand-side of each element of @var{references-graphs} is automatically made |
| 2612 | an input of the build process of @var{exp}. In the build environment, each |
| 2613 | @var{file-name} contains the reference graph of the corresponding item, in a simple |
| 2614 | text format. |
| 2615 | |
| 2616 | @var{allowed-references} must be either @code{#f} or a list of output names and packages. |
| 2617 | In the latter case, the list denotes store items that the result is allowed to |
| 2618 | refer to. Any reference to another store item will lead to a build error. |
| 2619 | |
| 2620 | The other arguments are as for @code{derivation} (@pxref{Derivations}). |
| 2621 | @end deffn |
| 2622 | |
| 2623 | @deffn {Monadic Procedure} gexp->script @var{name} @var{exp} |
| 2624 | Return an executable script @var{name} that runs @var{exp} using |
| 2625 | @var{guile} with @var{modules} in its search path. |
| 2626 | |
| 2627 | The example below builds a script that simply invokes the @command{ls} |
| 2628 | command: |
| 2629 | |
| 2630 | @example |
| 2631 | (use-modules (guix gexp) (gnu packages base)) |
| 2632 | |
| 2633 | (gexp->script "list-files" |
| 2634 | #~(execl (string-append #$coreutils "/bin/ls") |
| 2635 | "ls")) |
| 2636 | @end example |
| 2637 | |
| 2638 | When ``running'' it through the store (@pxref{The Store Monad, |
| 2639 | @code{run-with-store}}), we obtain a derivation that produces an |
| 2640 | executable file @file{/gnu/store/@dots{}-list-files} along these lines: |
| 2641 | |
| 2642 | @example |
| 2643 | #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds |
| 2644 | !# |
| 2645 | (execl (string-append "/gnu/store/@dots{}-coreutils-8.22"/bin/ls") |
| 2646 | "ls") |
| 2647 | @end example |
| 2648 | @end deffn |
| 2649 | |
| 2650 | @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} |
| 2651 | Return a derivation that builds a file @var{name} containing @var{exp}. |
| 2652 | |
| 2653 | The resulting file holds references to all the dependencies of @var{exp} |
| 2654 | or a subset thereof. |
| 2655 | @end deffn |
| 2656 | |
| 2657 | @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{} |
| 2658 | Return as a monadic value a derivation that builds a text file |
| 2659 | containing all of @var{text}. @var{text} may list, in addition to |
| 2660 | strings, packages, derivations, and store file names; the resulting |
| 2661 | store file holds references to all these. |
| 2662 | |
| 2663 | This variant should be preferred over @code{text-file} anytime the file |
| 2664 | to create will reference items from the store. This is typically the |
| 2665 | case when building a configuration file that embeds store file names, |
| 2666 | like this: |
| 2667 | |
| 2668 | @example |
| 2669 | (define (profile.sh) |
| 2670 | ;; Return the name of a shell script in the store that |
| 2671 | ;; initializes the 'PATH' environment variable. |
| 2672 | (text-file* "profile.sh" |
| 2673 | "export PATH=" coreutils "/bin:" |
| 2674 | grep "/bin:" sed "/bin\n")) |
| 2675 | @end example |
| 2676 | |
| 2677 | In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file |
| 2678 | will references @var{coreutils}, @var{grep}, and @var{sed}, thereby |
| 2679 | preventing them from being garbage-collected during its lifetime. |
| 2680 | @end deffn |
| 2681 | |
| 2682 | Of course, in addition to gexps embedded in ``host'' code, there are |
| 2683 | also modules containing build tools. To make it clear that they are |
| 2684 | meant to be used in the build stratum, these modules are kept in the |
| 2685 | @code{(guix build @dots{})} name space. |
| 2686 | |
| 2687 | |
| 2688 | @c ********************************************************************* |
| 2689 | @node Utilities |
| 2690 | @chapter Utilities |
| 2691 | |
| 2692 | This section describes tools primarily targeted at developers and users |
| 2693 | who write new package definitions. They complement the Scheme |
| 2694 | programming interface of Guix in a convenient way. |
| 2695 | |
| 2696 | @menu |
| 2697 | * Invoking guix build:: Building packages from the command line. |
| 2698 | * Invoking guix download:: Downloading a file and printing its hash. |
| 2699 | * Invoking guix hash:: Computing the cryptographic hash of a file. |
| 2700 | * Invoking guix import:: Importing package definitions. |
| 2701 | * Invoking guix refresh:: Updating package definitions. |
| 2702 | * Invoking guix lint:: Finding errors in package definitions. |
| 2703 | * Invoking guix environment:: Setting up development environments. |
| 2704 | @end menu |
| 2705 | |
| 2706 | @node Invoking guix build |
| 2707 | @section Invoking @command{guix build} |
| 2708 | |
| 2709 | The @command{guix build} command builds packages or derivations and |
| 2710 | their dependencies, and prints the resulting store paths. Note that it |
| 2711 | does not modify the user's profile---this is the job of the |
| 2712 | @command{guix package} command (@pxref{Invoking guix package}). Thus, |
| 2713 | it is mainly useful for distribution developers. |
| 2714 | |
| 2715 | The general syntax is: |
| 2716 | |
| 2717 | @example |
| 2718 | guix build @var{options} @var{package-or-derivation}@dots{} |
| 2719 | @end example |
| 2720 | |
| 2721 | @var{package-or-derivation} may be either the name of a package found in |
| 2722 | the software distribution such as @code{coreutils} or |
| 2723 | @code{coreutils-8.20}, or a derivation such as |
| 2724 | @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a |
| 2725 | package with the corresponding name (and optionally version) is searched |
| 2726 | for among the GNU distribution modules (@pxref{Package Modules}). |
| 2727 | |
| 2728 | Alternatively, the @code{--expression} option may be used to specify a |
| 2729 | Scheme expression that evaluates to a package; this is useful when |
| 2730 | disambiguation among several same-named packages or package variants is |
| 2731 | needed. |
| 2732 | |
| 2733 | The @var{options} may be zero or more of the following: |
| 2734 | |
| 2735 | @table @code |
| 2736 | |
| 2737 | @item --expression=@var{expr} |
| 2738 | @itemx -e @var{expr} |
| 2739 | Build the package or derivation @var{expr} evaluates to. |
| 2740 | |
| 2741 | For example, @var{expr} may be @code{(@@ (gnu packages guile) |
| 2742 | guile-1.8)}, which unambiguously designates this specific variant of |
| 2743 | version 1.8 of Guile. |
| 2744 | |
| 2745 | Alternately, @var{expr} may be a G-expression, in which case it is used |
| 2746 | as a build program passed to @code{gexp->derivation} |
| 2747 | (@pxref{G-Expressions}). |
| 2748 | |
| 2749 | Lastly, @var{expr} may refer to a zero-argument monadic procedure |
| 2750 | (@pxref{The Store Monad}). The procedure must return a derivation as a |
| 2751 | monadic value, which is then passed through @code{run-with-store}. |
| 2752 | |
| 2753 | @item --source |
| 2754 | @itemx -S |
| 2755 | Build the packages' source derivations, rather than the packages |
| 2756 | themselves. |
| 2757 | |
| 2758 | For instance, @code{guix build -S gcc} returns something like |
| 2759 | @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is GCC's source tarball. |
| 2760 | |
| 2761 | The returned source tarball is the result of applying any patches and |
| 2762 | code snippets specified in the package's @code{origin} (@pxref{Defining |
| 2763 | Packages}). |
| 2764 | |
| 2765 | @item --system=@var{system} |
| 2766 | @itemx -s @var{system} |
| 2767 | Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of |
| 2768 | the host's system type. |
| 2769 | |
| 2770 | An example use of this is on Linux-based systems, which can emulate |
| 2771 | different personalities. For instance, passing |
| 2772 | @code{--system=i686-linux} on an @code{x86_64-linux} system allows users |
| 2773 | to build packages in a complete 32-bit environment. |
| 2774 | |
| 2775 | @item --target=@var{triplet} |
| 2776 | @cindex cross-compilation |
| 2777 | Cross-build for @var{triplet}, which must be a valid GNU triplet, such |
| 2778 | as @code{"mips64el-linux-gnu"} (@pxref{Configuration Names, GNU |
| 2779 | configuration triplets,, configure, GNU Configure and Build System}). |
| 2780 | |
| 2781 | @item --with-source=@var{source} |
| 2782 | Use @var{source} as the source of the corresponding package. |
| 2783 | @var{source} must be a file name or a URL, as for @command{guix |
| 2784 | download} (@pxref{Invoking guix download}). |
| 2785 | |
| 2786 | The ``corresponding package'' is taken to be one specified on the |
| 2787 | command line whose name matches the base of @var{source}---e.g., if |
| 2788 | @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding |
| 2789 | package is @code{guile}. Likewise, the version string is inferred from |
| 2790 | @var{source}; in the previous example, it's @code{2.0.10}. |
| 2791 | |
| 2792 | This option allows users to try out versions of packages other than the |
| 2793 | one provided by the distribution. The example below downloads |
| 2794 | @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for |
| 2795 | the @code{ed} package: |
| 2796 | |
| 2797 | @example |
| 2798 | guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz |
| 2799 | @end example |
| 2800 | |
| 2801 | As a developer, @code{--with-source} makes it easy to test release |
| 2802 | candidates: |
| 2803 | |
| 2804 | @example |
| 2805 | guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz |
| 2806 | @end example |
| 2807 | |
| 2808 | @item --no-grafts |
| 2809 | Do not ``graft'' packages. In practice, this means that package updates |
| 2810 | available as grafts are not applied. @xref{Security Updates}, for more |
| 2811 | information on grafts. |
| 2812 | |
| 2813 | @item --derivations |
| 2814 | @itemx -d |
| 2815 | Return the derivation paths, not the output paths, of the given |
| 2816 | packages. |
| 2817 | |
| 2818 | @item --root=@var{file} |
| 2819 | @itemx -r @var{file} |
| 2820 | Make @var{file} a symlink to the result, and register it as a garbage |
| 2821 | collector root. |
| 2822 | |
| 2823 | @item --log-file |
| 2824 | Return the build log file names for the given |
| 2825 | @var{package-or-derivation}s, or raise an error if build logs are |
| 2826 | missing. |
| 2827 | |
| 2828 | This works regardless of how packages or derivations are specified. For |
| 2829 | instance, the following invocations are equivalent: |
| 2830 | |
| 2831 | @example |
| 2832 | guix build --log-file `guix build -d guile` |
| 2833 | guix build --log-file `guix build guile` |
| 2834 | guix build --log-file guile |
| 2835 | guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)' |
| 2836 | @end example |
| 2837 | |
| 2838 | |
| 2839 | @end table |
| 2840 | |
| 2841 | @cindex common build options |
| 2842 | In addition, a number of options that control the build process are |
| 2843 | common to @command{guix build} and other commands that can spawn builds, |
| 2844 | such as @command{guix package} or @command{guix archive}. These are the |
| 2845 | following: |
| 2846 | |
| 2847 | @table @code |
| 2848 | |
| 2849 | @item --load-path=@var{directory} |
| 2850 | @itemx -L @var{directory} |
| 2851 | Add @var{directory} to the front of the package module search path |
| 2852 | (@pxref{Package Modules}). |
| 2853 | |
| 2854 | This allows users to define their own packages and make them visible to |
| 2855 | the command-line tools. |
| 2856 | |
| 2857 | @item --keep-failed |
| 2858 | @itemx -K |
| 2859 | Keep the build tree of failed builds. Thus, if a build fail, its build |
| 2860 | tree is kept under @file{/tmp}, in a directory whose name is shown at |
| 2861 | the end of the build log. This is useful when debugging build issues. |
| 2862 | |
| 2863 | @item --dry-run |
| 2864 | @itemx -n |
| 2865 | Do not build the derivations. |
| 2866 | |
| 2867 | @item --fallback |
| 2868 | When substituting a pre-built binary fails, fall back to building |
| 2869 | packages locally. |
| 2870 | |
| 2871 | @item --no-substitutes |
| 2872 | Do not use substitutes for build products. That is, always build things |
| 2873 | locally instead of allowing downloads of pre-built binaries |
| 2874 | (@pxref{Substitutes}). |
| 2875 | |
| 2876 | @item --no-build-hook |
| 2877 | Do not attempt to offload builds @i{via} the daemon's ``build hook'' |
| 2878 | (@pxref{Daemon Offload Setup}). That is, always build things locally |
| 2879 | instead of offloading builds to remote machines. |
| 2880 | |
| 2881 | @item --max-silent-time=@var{seconds} |
| 2882 | When the build or substitution process remains silent for more than |
| 2883 | @var{seconds}, terminate it and report a build failure. |
| 2884 | |
| 2885 | @item --timeout=@var{seconds} |
| 2886 | Likewise, when the build or substitution process lasts for more than |
| 2887 | @var{seconds}, terminate it and report a build failure. |
| 2888 | |
| 2889 | By default there is no timeout. This behavior can be restored with |
| 2890 | @code{--timeout=0}. |
| 2891 | |
| 2892 | @item --verbosity=@var{level} |
| 2893 | Use the given verbosity level. @var{level} must be an integer between 0 |
| 2894 | and 5; higher means more verbose output. Setting a level of 4 or more |
| 2895 | may be helpful when debugging setup issues with the build daemon. |
| 2896 | |
| 2897 | @item --cores=@var{n} |
| 2898 | @itemx -c @var{n} |
| 2899 | Allow the use of up to @var{n} CPU cores for the build. The special |
| 2900 | value @code{0} means to use as many CPU cores as available. |
| 2901 | |
| 2902 | @item --max-jobs=@var{n} |
| 2903 | @itemx -M @var{n} |
| 2904 | Allow at most @var{n} build jobs in parallel. @xref{Invoking |
| 2905 | guix-daemon, @code{--max-jobs}}, for details about this option and the |
| 2906 | equivalent @command{guix-daemon} option. |
| 2907 | |
| 2908 | @end table |
| 2909 | |
| 2910 | Behind the scenes, @command{guix build} is essentially an interface to |
| 2911 | the @code{package-derivation} procedure of the @code{(guix packages)} |
| 2912 | module, and to the @code{build-derivations} procedure of the @code{(guix |
| 2913 | derivations)} module. |
| 2914 | |
| 2915 | In addition to options explicitly passed on the command line, |
| 2916 | @command{guix build} and other @command{guix} commands that support |
| 2917 | building honor the @code{GUIX_BUILD_OPTIONS} environment variable. |
| 2918 | |
| 2919 | @defvr {Environment Variable} GUIX_BUILD_OPTIONS |
| 2920 | Users can define this variable to a list of command line options that |
| 2921 | will automatically be used by @command{guix build} and other |
| 2922 | @command{guix} commands that can perform builds, as in the example |
| 2923 | below: |
| 2924 | |
| 2925 | @example |
| 2926 | $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar" |
| 2927 | @end example |
| 2928 | |
| 2929 | These options are parsed independently, and the result is appended to |
| 2930 | the parsed command-line options. |
| 2931 | @end defvr |
| 2932 | |
| 2933 | |
| 2934 | @node Invoking guix download |
| 2935 | @section Invoking @command{guix download} |
| 2936 | |
| 2937 | When writing a package definition, developers typically need to download |
| 2938 | the package's source tarball, compute its SHA256 hash, and write that |
| 2939 | hash in the package definition (@pxref{Defining Packages}). The |
| 2940 | @command{guix download} tool helps with this task: it downloads a file |
| 2941 | from the given URI, adds it to the store, and prints both its file name |
| 2942 | in the store and its SHA256 hash. |
| 2943 | |
| 2944 | The fact that the downloaded file is added to the store saves bandwidth: |
| 2945 | when the developer eventually tries to build the newly defined package |
| 2946 | with @command{guix build}, the source tarball will not have to be |
| 2947 | downloaded again because it is already in the store. It is also a |
| 2948 | convenient way to temporarily stash files, which may be deleted |
| 2949 | eventually (@pxref{Invoking guix gc}). |
| 2950 | |
| 2951 | The @command{guix download} command supports the same URIs as used in |
| 2952 | package definitions. In particular, it supports @code{mirror://} URIs. |
| 2953 | @code{https} URIs (HTTP over TLS) are supported @emph{provided} the |
| 2954 | Guile bindings for GnuTLS are available in the user's environment; when |
| 2955 | they are not available, an error is raised. @xref{Guile Preparations, |
| 2956 | how to install the GnuTLS bindings for Guile,, gnutls-guile, |
| 2957 | GnuTLS-Guile}, for more information. |
| 2958 | |
| 2959 | The following option is available: |
| 2960 | |
| 2961 | @table @code |
| 2962 | @item --format=@var{fmt} |
| 2963 | @itemx -f @var{fmt} |
| 2964 | Write the hash in the format specified by @var{fmt}. For more |
| 2965 | information on the valid values for @var{fmt}, @pxref{Invoking guix hash}. |
| 2966 | @end table |
| 2967 | |
| 2968 | @node Invoking guix hash |
| 2969 | @section Invoking @command{guix hash} |
| 2970 | |
| 2971 | The @command{guix hash} command computes the SHA256 hash of a file. |
| 2972 | It is primarily a convenience tool for anyone contributing to the |
| 2973 | distribution: it computes the cryptographic hash of a file, which can be |
| 2974 | used in the definition of a package (@pxref{Defining Packages}). |
| 2975 | |
| 2976 | The general syntax is: |
| 2977 | |
| 2978 | @example |
| 2979 | guix hash @var{option} @var{file} |
| 2980 | @end example |
| 2981 | |
| 2982 | @command{guix hash} has the following option: |
| 2983 | |
| 2984 | @table @code |
| 2985 | |
| 2986 | @item --format=@var{fmt} |
| 2987 | @itemx -f @var{fmt} |
| 2988 | Write the hash in the format specified by @var{fmt}. |
| 2989 | |
| 2990 | Supported formats: @code{nix-base32}, @code{base32}, @code{base16} |
| 2991 | (@code{hex} and @code{hexadecimal} can be used as well). |
| 2992 | |
| 2993 | If the @option{--format} option is not specified, @command{guix hash} |
| 2994 | will output the hash in @code{nix-base32}. This representation is used |
| 2995 | in the definitions of packages. |
| 2996 | |
| 2997 | @item --recursive |
| 2998 | @itemx -r |
| 2999 | Compute the hash on @var{file} recursively. |
| 3000 | |
| 3001 | In this case, the hash is computed on an archive containing @var{file}, |
| 3002 | including its children if it is a directory. Some of @var{file}'s |
| 3003 | meta-data is part of the archive; for instance, when @var{file} is a |
| 3004 | regular file, the hash is different depending on whether @var{file} is |
| 3005 | executable or not. Meta-data such as time stamps has no impact on the |
| 3006 | hash (@pxref{Invoking guix archive}). |
| 3007 | @c FIXME: Replace xref above with xref to an ``Archive'' section when |
| 3008 | @c it exists. |
| 3009 | |
| 3010 | @end table |
| 3011 | |
| 3012 | @node Invoking guix import |
| 3013 | @section Invoking @command{guix import} |
| 3014 | |
| 3015 | @cindex importing packages |
| 3016 | @cindex package import |
| 3017 | @cindex package conversion |
| 3018 | The @command{guix import} command is useful for people willing to add a |
| 3019 | package to the distribution but who'd rather do as little work as |
| 3020 | possible to get there---a legitimate demand. The command knows of a few |
| 3021 | repositories from which it can ``import'' package meta-data. The result |
| 3022 | is a package definition, or a template thereof, in the format we know |
| 3023 | (@pxref{Defining Packages}). |
| 3024 | |
| 3025 | The general syntax is: |
| 3026 | |
| 3027 | @example |
| 3028 | guix import @var{importer} @var{options}@dots{} |
| 3029 | @end example |
| 3030 | |
| 3031 | @var{importer} specifies the source from which to import package |
| 3032 | meta-data, and @var{options} specifies a package identifier and other |
| 3033 | options specific to @var{importer}. Currently, the available |
| 3034 | ``importers'' are: |
| 3035 | |
| 3036 | @table @code |
| 3037 | @item gnu |
| 3038 | Import meta-data for the given GNU package. This provides a template |
| 3039 | for the latest version of that GNU package, including the hash of its |
| 3040 | source tarball, and its canonical synopsis and description. |
| 3041 | |
| 3042 | Additional information such as the package's dependencies and its |
| 3043 | license needs to be figured out manually. |
| 3044 | |
| 3045 | For example, the following command returns a package definition for |
| 3046 | GNU@tie{}Hello: |
| 3047 | |
| 3048 | @example |
| 3049 | guix import gnu hello |
| 3050 | @end example |
| 3051 | |
| 3052 | Specific command-line options are: |
| 3053 | |
| 3054 | @table @code |
| 3055 | @item --key-download=@var{policy} |
| 3056 | As for @code{guix refresh}, specify the policy to handle missing OpenPGP |
| 3057 | keys when verifying the package's signature. @xref{Invoking guix |
| 3058 | refresh, @code{--key-download}}. |
| 3059 | @end table |
| 3060 | |
| 3061 | @item pypi |
| 3062 | @cindex pypi |
| 3063 | Import meta-data from the @uref{https://pypi.python.org/, Python Package |
| 3064 | Index}@footnote{This functionality requires Guile-JSON to be installed. |
| 3065 | @xref{Requirements}.}. Information is taken from the JSON-formatted |
| 3066 | description available at @code{pypi.python.org} and usually includes all |
| 3067 | the relevant information, including package dependencies. |
| 3068 | |
| 3069 | The command below imports meta-data for the @code{itsdangerous} Python |
| 3070 | package: |
| 3071 | |
| 3072 | @example |
| 3073 | guix import pypi itsdangerous |
| 3074 | @end example |
| 3075 | |
| 3076 | @item cpan |
| 3077 | @cindex CPAN |
| 3078 | Import meta-data from @uref{https://www.metacpan.org/, MetaCPAN}. |
| 3079 | Information is taken from the JSON-formatted meta-data provided through |
| 3080 | @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most |
| 3081 | relevant information. License information should be checked closely. |
| 3082 | Package dependencies are included but may in some cases needlessly |
| 3083 | include core Perl modules. |
| 3084 | |
| 3085 | The command command below imports meta-data for the @code{Acme::Boolean} |
| 3086 | Perl module: |
| 3087 | |
| 3088 | @example |
| 3089 | guix import cpan Acme::Boolean |
| 3090 | @end example |
| 3091 | |
| 3092 | @item nix |
| 3093 | Import meta-data from a local copy of the source of the |
| 3094 | @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This |
| 3095 | relies on the @command{nix-instantiate} command of |
| 3096 | @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are |
| 3097 | typically written in a mixture of Nix-language and Bash code. This |
| 3098 | command only imports the high-level package structure that is written in |
| 3099 | the Nix language. It normally includes all the basic fields of a |
| 3100 | package definition. |
| 3101 | |
| 3102 | When importing a GNU package, the synopsis and descriptions are replaced |
| 3103 | by their canonical upstream variant. |
| 3104 | |
| 3105 | As an example, the command below imports the package definition of |
| 3106 | LibreOffice (more precisely, it imports the definition of the package |
| 3107 | bound to the @code{libreoffice} top-level attribute): |
| 3108 | |
| 3109 | @example |
| 3110 | guix import nix ~/path/to/nixpkgs libreoffice |
| 3111 | @end example |
| 3112 | @end table |
| 3113 | |
| 3114 | The structure of the @command{guix import} code is modular. It would be |
| 3115 | useful to have more importers for other package formats, and your help |
| 3116 | is welcome here (@pxref{Contributing}). |
| 3117 | |
| 3118 | @node Invoking guix refresh |
| 3119 | @section Invoking @command{guix refresh} |
| 3120 | |
| 3121 | The primary audience of the @command{guix refresh} command is developers |
| 3122 | of the GNU software distribution. By default, it reports any packages |
| 3123 | provided by the distribution that are outdated compared to the latest |
| 3124 | upstream version, like this: |
| 3125 | |
| 3126 | @example |
| 3127 | $ guix refresh |
| 3128 | gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1 |
| 3129 | gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0 |
| 3130 | @end example |
| 3131 | |
| 3132 | It does so by browsing each package's FTP directory and determining the |
| 3133 | highest version number of the source tarballs |
| 3134 | therein@footnote{Currently, this only works for GNU packages.}. |
| 3135 | |
| 3136 | When passed @code{--update}, it modifies distribution source files to |
| 3137 | update the version numbers and source tarball hashes of those packages' |
| 3138 | recipes (@pxref{Defining Packages}). This is achieved by downloading |
| 3139 | each package's latest source tarball and its associated OpenPGP |
| 3140 | signature, authenticating the downloaded tarball against its signature |
| 3141 | using @command{gpg}, and finally computing its hash. When the public |
| 3142 | key used to sign the tarball is missing from the user's keyring, an |
| 3143 | attempt is made to automatically retrieve it from a public key server; |
| 3144 | when it's successful, the key is added to the user's keyring; otherwise, |
| 3145 | @command{guix refresh} reports an error. |
| 3146 | |
| 3147 | The following options are supported: |
| 3148 | |
| 3149 | @table @code |
| 3150 | |
| 3151 | @item --update |
| 3152 | @itemx -u |
| 3153 | Update distribution source files (package recipes) in place. |
| 3154 | @xref{Defining Packages}, for more information on package definitions. |
| 3155 | |
| 3156 | @item --select=[@var{subset}] |
| 3157 | @itemx -s @var{subset} |
| 3158 | Select all the packages in @var{subset}, one of @code{core} or |
| 3159 | @code{non-core}. |
| 3160 | |
| 3161 | The @code{core} subset refers to all the packages at the core of the |
| 3162 | distribution---i.e., packages that are used to build ``everything |
| 3163 | else''. This includes GCC, libc, Binutils, Bash, etc. Usually, |
| 3164 | changing one of these packages in the distribution entails a rebuild of |
| 3165 | all the others. Thus, such updates are an inconvenience to users in |
| 3166 | terms of build time or bandwidth used to achieve the upgrade. |
| 3167 | |
| 3168 | The @code{non-core} subset refers to the remaining packages. It is |
| 3169 | typically useful in cases where an update of the core packages would be |
| 3170 | inconvenient. |
| 3171 | |
| 3172 | @end table |
| 3173 | |
| 3174 | In addition, @command{guix refresh} can be passed one or more package |
| 3175 | names, as in this example: |
| 3176 | |
| 3177 | @example |
| 3178 | guix refresh -u emacs idutils |
| 3179 | @end example |
| 3180 | |
| 3181 | @noindent |
| 3182 | The command above specifically updates the @code{emacs} and |
| 3183 | @code{idutils} packages. The @code{--select} option would have no |
| 3184 | effect in this case. |
| 3185 | |
| 3186 | When considering whether to upgrade a package, it is sometimes |
| 3187 | convenient to know which packages would be affected by the upgrade and |
| 3188 | should be checked for compatibility. For this the following option may |
| 3189 | be used when passing @command{guix refresh} one or more package names: |
| 3190 | |
| 3191 | @table @code |
| 3192 | |
| 3193 | @item --list-dependent |
| 3194 | @itemx -l |
| 3195 | List top-level dependent packages that would need to be rebuilt as a |
| 3196 | result of upgrading one or more packages. |
| 3197 | |
| 3198 | @end table |
| 3199 | |
| 3200 | Be aware that the @code{--list-dependent} option only |
| 3201 | @emph{approximates} the rebuilds that would be required as a result of |
| 3202 | an upgrade. More rebuilds might be required under some circumstances. |
| 3203 | |
| 3204 | @example |
| 3205 | $ guix refresh --list-dependent flex |
| 3206 | Building the following 120 packages would ensure 213 dependent packages are rebuilt: |
| 3207 | hop-2.4.0 geiser-0.4 notmuch-0.18 mu-0.9.9.5 cflow-1.4 idutils-4.6 @dots{} |
| 3208 | @end example |
| 3209 | |
| 3210 | The command above lists a set of packages that could be built to check |
| 3211 | for compatibility with an upgraded @code{flex} package. |
| 3212 | |
| 3213 | The following options can be used to customize GnuPG operation: |
| 3214 | |
| 3215 | @table @code |
| 3216 | |
| 3217 | @item --gpg=@var{command} |
| 3218 | Use @var{command} as the GnuPG 2.x command. @var{command} is searched |
| 3219 | for in @code{$PATH}. |
| 3220 | |
| 3221 | @item --key-download=@var{policy} |
| 3222 | Handle missing OpenPGP keys according to @var{policy}, which may be one |
| 3223 | of: |
| 3224 | |
| 3225 | @table @code |
| 3226 | @item always |
| 3227 | Always download missing OpenPGP keys from the key server, and add them |
| 3228 | to the user's GnuPG keyring. |
| 3229 | |
| 3230 | @item never |
| 3231 | Never try to download missing OpenPGP keys. Instead just bail out. |
| 3232 | |
| 3233 | @item interactive |
| 3234 | When a package signed with an unknown OpenPGP key is encountered, ask |
| 3235 | the user whether to download it or not. This is the default behavior. |
| 3236 | @end table |
| 3237 | |
| 3238 | @item --key-server=@var{host} |
| 3239 | Use @var{host} as the OpenPGP key server when importing a public key. |
| 3240 | |
| 3241 | @end table |
| 3242 | |
| 3243 | @node Invoking guix lint |
| 3244 | @section Invoking @command{guix lint} |
| 3245 | The @command{guix lint} is meant to help package developers avoid common |
| 3246 | errors and use a consistent style. It runs a number of checks on a |
| 3247 | given set of packages in order to find common mistakes in their |
| 3248 | definitions. Available @dfn{checkers} include (see |
| 3249 | @code{--list-checkers} for a complete list): |
| 3250 | |
| 3251 | @table @code |
| 3252 | @item synopsis |
| 3253 | @itemx description |
| 3254 | Validate certain typographical and stylistic rules about package |
| 3255 | descriptions and synopses. |
| 3256 | |
| 3257 | @item inputs-should-be-native |
| 3258 | Identify inputs that should most likely be native inputs. |
| 3259 | |
| 3260 | @item source |
| 3261 | @itemx home-page |
| 3262 | Probe @code{home-page} and @code{source} URLs and report those that are |
| 3263 | invalid. |
| 3264 | @end table |
| 3265 | |
| 3266 | The general syntax is: |
| 3267 | |
| 3268 | @example |
| 3269 | guix lint @var{options} @var{package}@dots{} |
| 3270 | @end example |
| 3271 | |
| 3272 | If no package is given on the command line, then all packages are checked. |
| 3273 | The @var{options} may be zero or more of the following: |
| 3274 | |
| 3275 | @table @code |
| 3276 | |
| 3277 | @item --checkers |
| 3278 | @itemx -c |
| 3279 | Only enable the checkers specified in a comma-separated list using the |
| 3280 | names returned by @code{--list-checkers}. |
| 3281 | |
| 3282 | @item --list-checkers |
| 3283 | @itemx -l |
| 3284 | List and describe all the available checkers that will be run on packages |
| 3285 | and exit. |
| 3286 | |
| 3287 | @end table |
| 3288 | |
| 3289 | @node Invoking guix environment |
| 3290 | @section Invoking @command{guix environment} |
| 3291 | |
| 3292 | @cindex reproducible build environments |
| 3293 | The purpose of @command{guix environment} is to assist hackers in |
| 3294 | creating reproducible development environments without polluting their |
| 3295 | package profile. The @command{guix environment} tool takes one or more |
| 3296 | packages, builds all of the necessary inputs, and creates a shell |
| 3297 | environment to use them. |
| 3298 | |
| 3299 | The general syntax is: |
| 3300 | |
| 3301 | @example |
| 3302 | guix environment @var{options} @var{package}@dots{} |
| 3303 | @end example |
| 3304 | |
| 3305 | The following examples spawns a new shell that is capable of building |
| 3306 | the GNU Guile source code: |
| 3307 | |
| 3308 | @example |
| 3309 | guix environment guile |
| 3310 | @end example |
| 3311 | |
| 3312 | If the specified packages are not built yet, @command{guix environment} |
| 3313 | automatically builds them. The new shell's environment is an augmented |
| 3314 | version of the environment that @command{guix environment} was run in. |
| 3315 | It contains the necessary search paths for building the given package |
| 3316 | added to the existing environment variables. To create a ``pure'' |
| 3317 | environment in which the original environment variables have been unset, |
| 3318 | use the @code{--pure} option. |
| 3319 | |
| 3320 | Additionally, more than one package may be specified, in which case the |
| 3321 | union of the inputs for the given packages are used. For example, the |
| 3322 | command below spawns a shell where all of the dependencies of both Guile |
| 3323 | and Emacs are available: |
| 3324 | |
| 3325 | @example |
| 3326 | guix environment guile emacs |
| 3327 | @end example |
| 3328 | |
| 3329 | Sometimes an interactive shell session is not desired. The |
| 3330 | @code{--exec} option can be used to specify the command to run instead. |
| 3331 | |
| 3332 | @example |
| 3333 | guix environment guile --exec=make |
| 3334 | @end example |
| 3335 | |
| 3336 | The following options are available: |
| 3337 | |
| 3338 | @table @code |
| 3339 | @item --expression=@var{expr} |
| 3340 | @itemx -e @var{expr} |
| 3341 | Create an environment for the package that @var{expr} evaluates to. |
| 3342 | |
| 3343 | @item --load=@var{file} |
| 3344 | @itemx -l @var{file} |
| 3345 | Create an environment for the package that the code within @var{file} |
| 3346 | evaluates to. |
| 3347 | |
| 3348 | @item --exec=@var{command} |
| 3349 | @item -E @var{command} |
| 3350 | Execute @var{command} in the new environment. |
| 3351 | |
| 3352 | @item --pure |
| 3353 | Unset existing environment variables when building the new environment. |
| 3354 | This has the effect of creating an environment in which search paths |
| 3355 | only contain package inputs. |
| 3356 | |
| 3357 | @item --search-paths |
| 3358 | Display the environment variable definitions that make up the |
| 3359 | environment. |
| 3360 | @end table |
| 3361 | |
| 3362 | It also supports all of the common build options that @command{guix |
| 3363 | build} supports (@pxref{Invoking guix build, common build options}). |
| 3364 | |
| 3365 | @c ********************************************************************* |
| 3366 | @node GNU Distribution |
| 3367 | @chapter GNU Distribution |
| 3368 | |
| 3369 | @cindex Guix System Distribution |
| 3370 | @cindex GSD |
| 3371 | Guix comes with a distribution of the GNU system consisting entirely of |
| 3372 | free software@footnote{The term ``free'' here refers to the |
| 3373 | @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to |
| 3374 | users of that software}.}. The |
| 3375 | distribution can be installed on its own (@pxref{System Installation}), |
| 3376 | but it is also possible to install Guix as a package manager on top of |
| 3377 | an installed GNU/Linux system (@pxref{Installation}). To distinguish |
| 3378 | between the two, we refer to the standalone distribution as the Guix |
| 3379 | System Distribution, or GNU@tie{}GSD. |
| 3380 | |
| 3381 | The distribution provides core GNU packages such as GNU libc, GCC, and |
| 3382 | Binutils, as well as many GNU and non-GNU applications. The complete |
| 3383 | list of available packages can be browsed |
| 3384 | @url{http://www.gnu.org/software/guix/package-list.html,on-line} or by |
| 3385 | running @command{guix package} (@pxref{Invoking guix package}): |
| 3386 | |
| 3387 | @example |
| 3388 | guix package --list-available |
| 3389 | @end example |
| 3390 | |
| 3391 | Our goal has been to provide a practical 100% free software distribution of |
| 3392 | Linux-based and other variants of GNU, with a focus on the promotion and |
| 3393 | tight integration of GNU components, and an emphasis on programs and |
| 3394 | tools that help users exert that freedom. |
| 3395 | |
| 3396 | Packages are currently available on the following platforms: |
| 3397 | |
| 3398 | @table @code |
| 3399 | |
| 3400 | @item x86_64-linux |
| 3401 | Intel/AMD @code{x86_64} architecture, Linux-Libre kernel; |
| 3402 | |
| 3403 | @item i686-linux |
| 3404 | Intel 32-bit architecture (IA32), Linux-Libre kernel; |
| 3405 | |
| 3406 | @item armhf-linux |
| 3407 | ARMv7-A architecture with hard float, Thumb-2 and VFP3D16 coprocessor, |
| 3408 | using the EABI hard-float ABI, and Linux-Libre kernel. |
| 3409 | |
| 3410 | @item mips64el-linux |
| 3411 | little-endian 64-bit MIPS processors, specifically the Loongson series, |
| 3412 | n32 application binary interface (ABI), and Linux-Libre kernel. |
| 3413 | |
| 3414 | @end table |
| 3415 | |
| 3416 | GSD itself is currently only available on @code{i686} and @code{x86_64}. |
| 3417 | |
| 3418 | @noindent |
| 3419 | For information on porting to other architectures or kernels, |
| 3420 | @xref{Porting}. |
| 3421 | |
| 3422 | @menu |
| 3423 | * System Installation:: Installing the whole operating system. |
| 3424 | * System Configuration:: Configuring the operating system. |
| 3425 | * Installing Debugging Files:: Feeding the debugger. |
| 3426 | * Security Updates:: Deploying security fixes quickly. |
| 3427 | * Package Modules:: Packages from the programmer's viewpoint. |
| 3428 | * Packaging Guidelines:: Growing the distribution. |
| 3429 | * Bootstrapping:: GNU/Linux built from scratch. |
| 3430 | * Porting:: Targeting another platform or kernel. |
| 3431 | @end menu |
| 3432 | |
| 3433 | Building this distribution is a cooperative effort, and you are invited |
| 3434 | to join! @xref{Contributing}, for information about how you can help. |
| 3435 | |
| 3436 | @node System Installation |
| 3437 | @section System Installation |
| 3438 | |
| 3439 | @cindex Guix System Distribution |
| 3440 | This section explains how to install the Guix System Distribution |
| 3441 | on a machine. The Guix package manager can |
| 3442 | also be installed on top of a running GNU/Linux system, |
| 3443 | @pxref{Installation}. |
| 3444 | |
| 3445 | @ifinfo |
| 3446 | @c This paragraph is for people reading this from tty2 of the |
| 3447 | @c installation image. |
| 3448 | You're reading this documentation with an Info reader. For details on |
| 3449 | how to use it, hit the @key{RET} key (``return'' or ``enter'') on the |
| 3450 | link that follows: @pxref{Help,,, info, Info: An Introduction}. Hit |
| 3451 | @kbd{l} afterwards to come back here. |
| 3452 | @end ifinfo |
| 3453 | |
| 3454 | @subsection Limitations |
| 3455 | |
| 3456 | As of version @value{VERSION}, the Guix System Distribution (GSD) is |
| 3457 | not production-ready. It may contain bugs and lack important |
| 3458 | features. Thus, if you are looking for a stable production system that |
| 3459 | respects your freedom as a computer user, a good solution at this point |
| 3460 | is to consider @url{http://www.gnu.org/distros/free-distros.html, one of |
| 3461 | more established GNU/Linux distributions}. We hope you can soon switch |
| 3462 | to the GSD without fear, of course. In the meantime, you can |
| 3463 | also keep using your distribution and try out the package manager on top |
| 3464 | of it (@pxref{Installation}). |
| 3465 | |
| 3466 | Before you proceed with the installation, be aware of the following |
| 3467 | noteworthy limitations applicable to version @value{VERSION}: |
| 3468 | |
| 3469 | @itemize |
| 3470 | @item |
| 3471 | The installation process does not include a graphical user interface and |
| 3472 | requires familiarity with GNU/Linux (see the following subsections to |
| 3473 | get a feel of what that means.) |
| 3474 | |
| 3475 | @item |
| 3476 | The system does not yet provide GNOME and KDE; it provides Xfce, though, |
| 3477 | if graphical desktop environments are your thing. |
| 3478 | |
| 3479 | @item |
| 3480 | Support for the Logical Volume Manager (LVM) is missing. |
| 3481 | |
| 3482 | @item |
| 3483 | Few system services are currently supported out-of-the-box |
| 3484 | (@pxref{Services}). |
| 3485 | |
| 3486 | @item |
| 3487 | On the order of 1,200 packages are available, which means that you may |
| 3488 | occasionally find that a useful package is missing. |
| 3489 | @end itemize |
| 3490 | |
| 3491 | You've been warned. But more than a disclaimer, this is an invitation |
| 3492 | to report issues (and success stories!), and join us in improving it. |
| 3493 | @xref{Contributing}, for more info. |
| 3494 | |
| 3495 | @subsection USB Stick Installation |
| 3496 | |
| 3497 | An installation image for USB sticks can be downloaded from |
| 3498 | @code{ftp://alpha.gnu.org/gnu/guix/gsd-usb-install-@value{VERSION}.@var{system}.xz}, |
| 3499 | where @var{system} is one of: |
| 3500 | |
| 3501 | @table @code |
| 3502 | @item x86_64-linux |
| 3503 | for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs; |
| 3504 | |
| 3505 | @item i686-linux |
| 3506 | for a 32-bit GNU/Linux system on Intel-compatible CPUs. |
| 3507 | @end table |
| 3508 | |
| 3509 | This image contains a single partition with the tools necessary for an |
| 3510 | installation. It is meant to be copied @emph{as is} to a large-enough |
| 3511 | USB stick. |
| 3512 | |
| 3513 | To copy the image to a USB stick, follow these steps: |
| 3514 | |
| 3515 | @enumerate |
| 3516 | @item |
| 3517 | Decompress the image using the @command{xz} command: |
| 3518 | |
| 3519 | @example |
| 3520 | xz -d gsd-usb-install-@value{VERSION}.@var{system}.xz |
| 3521 | @end example |
| 3522 | |
| 3523 | @item |
| 3524 | Insert a USB stick of 1@tie{}GiB or more in your machine, and determine |
| 3525 | its device name. Assuming that USB stick is known as @file{/dev/sdX}, |
| 3526 | copy the image with: |
| 3527 | |
| 3528 | @example |
| 3529 | dd if=gsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX |
| 3530 | @end example |
| 3531 | |
| 3532 | Access to @file{/dev/sdX} usually requires root privileges. |
| 3533 | @end enumerate |
| 3534 | |
| 3535 | Once this is done, you should be able to reboot the system and boot from |
| 3536 | the USB stick. The latter usually requires you to get in the BIOS' boot |
| 3537 | menu, where you can choose to boot from the USB stick. |
| 3538 | |
| 3539 | @subsection Preparing for Installation |
| 3540 | |
| 3541 | Once you have successfully booted the image on the USB stick, you should |
| 3542 | end up with a root prompt. Several console TTYs are configured and can |
| 3543 | be used to run commands as root. TTY2 shows this documentation, |
| 3544 | browsable using the Info reader commands (@pxref{Help,,, info, Info: An |
| 3545 | Introduction}). |
| 3546 | |
| 3547 | To install the system, you would: |
| 3548 | |
| 3549 | @enumerate |
| 3550 | |
| 3551 | @item |
| 3552 | Configure the network, by running @command{dhclient eno1} (to get an |
| 3553 | automatically assigned IP address from the wired network interface |
| 3554 | controller@footnote{ |
| 3555 | @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20 |
| 3556 | The name @code{eno1} is for the first on-board Ethernet controller. The |
| 3557 | interface name for an Ethernet controller that is in the first slot of |
| 3558 | the first PCI bus, for instance, would be @code{enp1s0}. Use |
| 3559 | @command{ifconfig -a} to list all the available network interfaces.}), |
| 3560 | or using the @command{ifconfig} command. |
| 3561 | |
| 3562 | The system automatically loads drivers for your network interface |
| 3563 | controllers. |
| 3564 | |
| 3565 | Setting up network access is almost always a requirement because the |
| 3566 | image does not contain all the software and tools that may be needed. |
| 3567 | |
| 3568 | @item |
| 3569 | Unless this has already been done, you must partition and format the |
| 3570 | target partitions. |
| 3571 | |
| 3572 | Preferably, assign partitions a label so that you can easily and |
| 3573 | reliably refer to them in @code{file-system} declarations (@pxref{File |
| 3574 | Systems}). This is typically done using the @code{-L} option of |
| 3575 | @command{mkfs.ext4} and related commands. |
| 3576 | |
| 3577 | The installation image includes Parted (@pxref{Overview,,, parted, GNU |
| 3578 | Parted User Manual}), @command{fdisk}, Cryptsetup/LUKS for disk |
| 3579 | encryption, and e2fsprogs, the suite of tools to manipulate |
| 3580 | ext2/ext3/ext4 file systems. |
| 3581 | |
| 3582 | @item |
| 3583 | Once that is done, mount the target root partition under @file{/mnt}. |
| 3584 | |
| 3585 | @item |
| 3586 | Lastly, run @code{deco start cow-store /mnt}. |
| 3587 | |
| 3588 | This will make @file{/gnu/store} copy-on-write, such that packages added |
| 3589 | to it during the installation phase will be written to the target disk |
| 3590 | rather than kept in memory. |
| 3591 | |
| 3592 | @end enumerate |
| 3593 | |
| 3594 | |
| 3595 | @subsection Proceeding with the Installation |
| 3596 | |
| 3597 | With the target partitions ready, you now have to edit a file and |
| 3598 | provide the declaration of the operating system to be installed. To |
| 3599 | that end, the installation system comes with two text editors: GNU nano |
| 3600 | (@pxref{Top,,, nano, GNU nano Manual}), and GNU Zile, an Emacs clone. |
| 3601 | It is better to store that file on the target root file system, say, as |
| 3602 | @file{/mnt/etc/config.scm}. |
| 3603 | |
| 3604 | A minimal operating system configuration, with just the bare minimum and |
| 3605 | only a root account would look like this (on the installation system, |
| 3606 | this example is available as @file{/etc/configuration-template.scm}): |
| 3607 | |
| 3608 | @example |
| 3609 | @include os-config.texi |
| 3610 | @end example |
| 3611 | |
| 3612 | @noindent |
| 3613 | For more information on @code{operating-system} declarations, |
| 3614 | @pxref{Using the Configuration System}. |
| 3615 | |
| 3616 | Once that is done, the new system must be initialized (remember that the |
| 3617 | target root file system is mounted under @file{/mnt}): |
| 3618 | |
| 3619 | @example |
| 3620 | guix system init /mnt/etc/config.scm /mnt |
| 3621 | @end example |
| 3622 | |
| 3623 | @noindent |
| 3624 | This will copy all the necessary files, and install GRUB on |
| 3625 | @file{/dev/sdX}, unless you pass the @option{--no-grub} option. For |
| 3626 | more information, @pxref{Invoking guix system}. This command may trigger |
| 3627 | downloads or builds of missing packages, which can take some time. |
| 3628 | |
| 3629 | Once that command has completed---and hopefully succeeded!---you can |
| 3630 | run @command{reboot} and boot into the new system. Cross fingers, and |
| 3631 | join us on @code{#guix} on the Freenode IRC network or on |
| 3632 | @file{guix-devel@@gnu.org} to share your experience---good or not so |
| 3633 | good. |
| 3634 | |
| 3635 | @subsection Building the Installation Image |
| 3636 | |
| 3637 | The installation image described above was built using the @command{guix |
| 3638 | system} command, specifically: |
| 3639 | |
| 3640 | @example |
| 3641 | guix system disk-image --image-size=850MiB gnu/system/install.scm |
| 3642 | @end example |
| 3643 | |
| 3644 | @xref{Invoking guix system}, for more information. See |
| 3645 | @file{gnu/system/install.scm} in the source tree for more information |
| 3646 | about the installation image. |
| 3647 | |
| 3648 | @node System Configuration |
| 3649 | @section System Configuration |
| 3650 | |
| 3651 | @cindex system configuration |
| 3652 | The Guix System Distribution supports a consistent whole-system configuration |
| 3653 | mechanism. By that we mean that all aspects of the global system |
| 3654 | configuration---such as the available system services, timezone and |
| 3655 | locale settings, user accounts---are declared in a single place. Such |
| 3656 | a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected. |
| 3657 | |
| 3658 | One of the advantages of putting all the system configuration under the |
| 3659 | control of Guix is that it supports transactional system upgrades, and |
| 3660 | makes it possible to roll-back to a previous system instantiation, |
| 3661 | should something go wrong with the new one (@pxref{Features}). Another |
| 3662 | one is that it makes it easy to replicate the exact same configuration |
| 3663 | across different machines, or at different points in time, without |
| 3664 | having to resort to additional administration tools layered on top of |
| 3665 | the system's own tools. |
| 3666 | @c Yes, we're talking of Puppet, Chef, & co. here. ↑ |
| 3667 | |
| 3668 | This section describes this mechanism. First we focus on the system |
| 3669 | administrator's viewpoint---explaining how the system is configured and |
| 3670 | instantiated. Then we show how this mechanism can be extended, for |
| 3671 | instance to support new system services. |
| 3672 | |
| 3673 | @menu |
| 3674 | * Using the Configuration System:: Customizing your GNU system. |
| 3675 | * operating-system Reference:: Detail of operating-system declarations. |
| 3676 | * File Systems:: Configuring file system mounts. |
| 3677 | * Mapped Devices:: Block device extra processing. |
| 3678 | * User Accounts:: Specifying user accounts. |
| 3679 | * Locales:: Language and cultural convention settings. |
| 3680 | * Services:: Specifying system services. |
| 3681 | * Setuid Programs:: Programs running with root privileges. |
| 3682 | * Name Service Switch:: Configuring libc's name service switch. |
| 3683 | * Initial RAM Disk:: Linux-Libre bootstrapping. |
| 3684 | * GRUB Configuration:: Configuring the boot loader. |
| 3685 | * Invoking guix system:: Instantiating a system configuration. |
| 3686 | * Defining Services:: Adding new service definitions. |
| 3687 | @end menu |
| 3688 | |
| 3689 | @node Using the Configuration System |
| 3690 | @subsection Using the Configuration System |
| 3691 | |
| 3692 | The operating system is configured by providing an |
| 3693 | @code{operating-system} declaration in a file that can then be passed to |
| 3694 | the @command{guix system} command (@pxref{Invoking guix system}). A |
| 3695 | simple setup, with the default system services, the default Linux-Libre |
| 3696 | kernel, initial RAM disk, and boot loader looks like this: |
| 3697 | |
| 3698 | @findex operating-system |
| 3699 | @lisp |
| 3700 | (use-modules (gnu) ; for 'user-account', '%base-services', etc. |
| 3701 | (gnu packages emacs) ; for 'emacs' |
| 3702 | (gnu services ssh)) ; for 'lsh-service' |
| 3703 | |
| 3704 | (operating-system |
| 3705 | (host-name "komputilo") |
| 3706 | (timezone "Europe/Paris") |
| 3707 | (locale "fr_FR.utf8") |
| 3708 | (bootloader (grub-configuration |
| 3709 | (device "/dev/sda"))) |
| 3710 | (file-systems (cons (file-system |
| 3711 | (device "/dev/sda1") ; or partition label |
| 3712 | (mount-point "/") |
| 3713 | (type "ext3")) |
| 3714 | %base-file-systems)) |
| 3715 | (users (list (user-account |
| 3716 | (name "alice") |
| 3717 | (group "users") |
| 3718 | (comment "Bob's sister") |
| 3719 | (home-directory "/home/alice")))) |
| 3720 | (packages (cons emacs %base-packages)) |
| 3721 | (services (cons (lsh-service #:port 2222 #:root-login? #t) |
| 3722 | %base-services))) |
| 3723 | @end lisp |
| 3724 | |
| 3725 | This example should be self-describing. Some of the fields defined |
| 3726 | above, such as @code{host-name} and @code{bootloader}, are mandatory. |
| 3727 | Others, such as @code{packages} and @code{services}, can be omitted, in |
| 3728 | which case they get a default value. |
| 3729 | |
| 3730 | @vindex %base-packages |
| 3731 | The @code{packages} field lists |
| 3732 | packages that will be globally visible on the system, for all user |
| 3733 | accounts---i.e., in every user's @code{PATH} environment variable---in |
| 3734 | addition to the per-user profiles (@pxref{Invoking guix package}). The |
| 3735 | @var{%base-packages} variable provides all the tools one would expect |
| 3736 | for basic user and administrator tasks---including the GNU Core |
| 3737 | Utilities, the GNU Networking Utilities, the GNU Zile lightweight text |
| 3738 | editor, @command{find}, @command{grep}, etc. The example above adds |
| 3739 | Emacs to those, taken from the @code{(gnu packages emacs)} module |
| 3740 | (@pxref{Package Modules}). |
| 3741 | |
| 3742 | @vindex %base-services |
| 3743 | The @code{services} field lists @dfn{system services} to be made |
| 3744 | available when the system starts (@pxref{Services}). |
| 3745 | The @code{operating-system} declaration above specifies that, in |
| 3746 | addition to the basic services, we want the @command{lshd} secure shell |
| 3747 | daemon listening on port 2222, and allowing remote @code{root} logins |
| 3748 | (@pxref{Invoking lshd,,, lsh, GNU lsh Manual}). Under the hood, |
| 3749 | @code{lsh-service} arranges so that @code{lshd} is started with the |
| 3750 | right command-line options, possibly with supporting configuration files |
| 3751 | generated as needed (@pxref{Defining Services}). @xref{operating-system |
| 3752 | Reference}, for details about the available @code{operating-system} |
| 3753 | fields. |
| 3754 | |
| 3755 | Assuming the above snippet is stored in the @file{my-system-config.scm} |
| 3756 | file, the @command{guix system reconfigure my-system-config.scm} command |
| 3757 | instantiates that configuration, and makes it the default GRUB boot |
| 3758 | entry (@pxref{Invoking guix system}). The normal way to change the |
| 3759 | system's configuration is by updating this file and re-running the |
| 3760 | @command{guix system} command. |
| 3761 | |
| 3762 | At the Scheme level, the bulk of an @code{operating-system} declaration |
| 3763 | is instantiated with the following monadic procedure (@pxref{The Store |
| 3764 | Monad}): |
| 3765 | |
| 3766 | @deffn {Monadic Procedure} operating-system-derivation os |
| 3767 | Return a derivation that builds @var{os}, an @code{operating-system} |
| 3768 | object (@pxref{Derivations}). |
| 3769 | |
| 3770 | The output of the derivation is a single directory that refers to all |
| 3771 | the packages, configuration files, and other supporting files needed to |
| 3772 | instantiate @var{os}. |
| 3773 | @end deffn |
| 3774 | |
| 3775 | @node operating-system Reference |
| 3776 | @subsection @code{operating-system} Reference |
| 3777 | |
| 3778 | This section summarizes all the options available in |
| 3779 | @code{operating-system} declarations (@pxref{Using the Configuration |
| 3780 | System}). |
| 3781 | |
| 3782 | @deftp {Data Type} operating-system |
| 3783 | This is the data type representing an operating system configuration. |
| 3784 | By that, we mean all the global system configuration, not per-user |
| 3785 | configuration (@pxref{Using the Configuration System}). |
| 3786 | |
| 3787 | @table @asis |
| 3788 | @item @code{kernel} (default: @var{linux-libre}) |
| 3789 | The package object of the operating system to use@footnote{Currently |
| 3790 | only the Linux-libre kernel is supported. In the future, it will be |
| 3791 | possible to use the GNU@tie{}Hurd.}. |
| 3792 | |
| 3793 | @item @code{bootloader} |
| 3794 | The system bootloader configuration object. @xref{GRUB Configuration}. |
| 3795 | |
| 3796 | @item @code{initrd} (default: @code{base-initrd}) |
| 3797 | A two-argument monadic procedure that returns an initial RAM disk for |
| 3798 | the Linux kernel. @xref{Initial RAM Disk}. |
| 3799 | |
| 3800 | @item @code{firmware} (default: @var{%base-firmware}) |
| 3801 | @cindex firmware |
| 3802 | List of firmware packages loadable by the operating system kernel. |
| 3803 | |
| 3804 | The default includes firmware needed for Atheros-based WiFi devices |
| 3805 | (Linux-libre module @code{ath9k}.) |
| 3806 | |
| 3807 | @item @code{host-name} |
| 3808 | The host name. |
| 3809 | |
| 3810 | @item @code{hosts-file} |
| 3811 | @cindex hosts file |
| 3812 | A zero-argument monadic procedure that returns a text file for use as |
| 3813 | @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library |
| 3814 | Reference Manual}). The default is to produce a file with entries for |
| 3815 | @code{localhost} and @var{host-name}. |
| 3816 | |
| 3817 | @item @code{mapped-devices} (default: @code{'()}) |
| 3818 | A list of mapped devices. @xref{Mapped Devices}. |
| 3819 | |
| 3820 | @item @code{file-systems} |
| 3821 | A list of file systems. @xref{File Systems}. |
| 3822 | |
| 3823 | @item @code{swap-devices} (default: @code{'()}) |
| 3824 | @cindex swap devices |
| 3825 | A list of strings identifying devices to be used for ``swap space'' |
| 3826 | (@pxref{Memory Concepts,,, libc, The GNU C Library Reference Manual}). |
| 3827 | For example, @code{'("/dev/sda3")}. |
| 3828 | |
| 3829 | @item @code{users} (default: @code{'()}) |
| 3830 | @itemx @code{groups} (default: @var{%base-groups}) |
| 3831 | List of user accounts and groups. @xref{User Accounts}. |
| 3832 | |
| 3833 | @item @code{skeletons} (default: @code{(default-skeletons)}) |
| 3834 | A monadic list of pairs of target file name and files. These are the |
| 3835 | files that will be used as skeletons as new accounts are created. |
| 3836 | |
| 3837 | For instance, a valid value may look like this: |
| 3838 | |
| 3839 | @example |
| 3840 | (mlet %store-monad ((bashrc (text-file "bashrc" "\ |
| 3841 | export PATH=$HOME/.guix-profile/bin"))) |
| 3842 | (return `((".bashrc" ,bashrc)))) |
| 3843 | @end example |
| 3844 | |
| 3845 | @item @code{issue} (default: @var{%default-issue}) |
| 3846 | A string denoting the contents of the @file{/etc/issue} file, which is |
| 3847 | what displayed when users log in on a text console. |
| 3848 | |
| 3849 | @item @code{packages} (default: @var{%base-packages}) |
| 3850 | The set of packages installed in the global profile, which is accessible |
| 3851 | at @file{/run/current-system/profile}. |
| 3852 | |
| 3853 | The default set includes core utilities, but it is good practice to |
| 3854 | install non-core utilities in user profiles (@pxref{Invoking guix |
| 3855 | package}). |
| 3856 | |
| 3857 | @item @code{timezone} |
| 3858 | A timezone identifying string---e.g., @code{"Europe/Paris"}. |
| 3859 | |
| 3860 | @item @code{locale} (default: @code{"en_US.utf8"}) |
| 3861 | The name of the default locale (@pxref{Locale Names,,, libc, The GNU C |
| 3862 | Library Reference Manual}). @xref{Locales}, for more information. |
| 3863 | |
| 3864 | @item @code{locale-definitions} (default: @var{%default-locale-definitions}) |
| 3865 | The list of locale definitions to be compiled and that may be used at |
| 3866 | run time. @xref{Locales}. |
| 3867 | |
| 3868 | @item @code{name-service-switch} (default: @var{%default-nss}) |
| 3869 | Configuration of libc's name service switch (NSS)---a |
| 3870 | @code{<name-service-switch>} object. @xref{Name Service Switch}, for |
| 3871 | details. |
| 3872 | |
| 3873 | @item @code{services} (default: @var{%base-services}) |
| 3874 | A list of monadic values denoting system services. @xref{Services}. |
| 3875 | |
| 3876 | @item @code{pam-services} (default: @code{(base-pam-services)}) |
| 3877 | @cindex PAM |
| 3878 | @cindex pluggable authentication modules |
| 3879 | Linux @dfn{pluggable authentication module} (PAM) services. |
| 3880 | @c FIXME: Add xref to PAM services section. |
| 3881 | |
| 3882 | @item @code{setuid-programs} (default: @var{%setuid-programs}) |
| 3883 | List of string-valued G-expressions denoting setuid programs. |
| 3884 | @xref{Setuid Programs}. |
| 3885 | |
| 3886 | @item @code{sudoers} (default: @var{%sudoers-specification}) |
| 3887 | @cindex sudoers |
| 3888 | The contents of the @file{/etc/sudoers} file as a string. |
| 3889 | |
| 3890 | This file specifies which users can use the @command{sudo} command, what |
| 3891 | they are allowed to do, and what privileges they may gain. The default |
| 3892 | is that only @code{root} and members of the @code{wheel} group may use |
| 3893 | @code{sudo}. |
| 3894 | |
| 3895 | @end table |
| 3896 | @end deftp |
| 3897 | |
| 3898 | @node File Systems |
| 3899 | @subsection File Systems |
| 3900 | |
| 3901 | The list of file systems to be mounted is specified in the |
| 3902 | @code{file-systems} field of the operating system's declaration |
| 3903 | (@pxref{Using the Configuration System}). Each file system is declared |
| 3904 | using the @code{file-system} form, like this: |
| 3905 | |
| 3906 | @example |
| 3907 | (file-system |
| 3908 | (mount-point "/home") |
| 3909 | (device "/dev/sda3") |
| 3910 | (type "ext4")) |
| 3911 | @end example |
| 3912 | |
| 3913 | As usual, some of the fields are mandatory---those shown in the example |
| 3914 | above---while others can be omitted. These are described below. |
| 3915 | |
| 3916 | @deftp {Data Type} file-system |
| 3917 | Objects of this type represent file systems to be mounted. They |
| 3918 | contain the following members: |
| 3919 | |
| 3920 | @table @asis |
| 3921 | @item @code{type} |
| 3922 | This is a string specifying the type of the file system---e.g., |
| 3923 | @code{"ext4"}. |
| 3924 | |
| 3925 | @item @code{mount-point} |
| 3926 | This designates the place where the file system is to be mounted. |
| 3927 | |
| 3928 | @item @code{device} |
| 3929 | This names the ``source'' of the file system. By default it is the name |
| 3930 | of a node under @file{/dev}, but its meaning depends on the @code{title} |
| 3931 | field described below. |
| 3932 | |
| 3933 | @item @code{title} (default: @code{'device}) |
| 3934 | This is a symbol that specifies how the @code{device} field is to be |
| 3935 | interpreted. |
| 3936 | |
| 3937 | When it is the symbol @code{device}, then the @code{device} field is |
| 3938 | interpreted as a file name; when it is @code{label}, then @code{device} |
| 3939 | is interpreted as a partition label name; when it is @code{uuid}, |
| 3940 | @code{device} is interpreted as a partition unique identifier (UUID). |
| 3941 | |
| 3942 | The @code{label} and @code{uuid} options offer a way to refer to disk |
| 3943 | partitions without having to hard-code their actual device name. |
| 3944 | |
| 3945 | However, when a file system's source is a mapped device (@pxref{Mapped |
| 3946 | Devices}), its @code{device} field @emph{must} refer to the mapped |
| 3947 | device name---e.g., @file{/dev/mapper/root-partition}---and consequently |
| 3948 | @code{title} must be set to @code{'device}. This is required so that |
| 3949 | the system knows that mounting the file system depends on having the |
| 3950 | corresponding device mapping established. |
| 3951 | |
| 3952 | @item @code{flags} (default: @code{'()}) |
| 3953 | This is a list of symbols denoting mount flags. Recognized flags |
| 3954 | include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow |
| 3955 | access to special files), @code{no-suid} (ignore setuid and setgid |
| 3956 | bits), and @code{no-exec} (disallow program execution.) |
| 3957 | |
| 3958 | @item @code{options} (default: @code{#f}) |
| 3959 | This is either @code{#f}, or a string denoting mount options. |
| 3960 | |
| 3961 | @item @code{needed-for-boot?} (default: @code{#f}) |
| 3962 | This Boolean value indicates whether the file system is needed when |
| 3963 | booting. If that is true, then the file system is mounted when the |
| 3964 | initial RAM disk (initrd) is loaded. This is always the case, for |
| 3965 | instance, for the root file system. |
| 3966 | |
| 3967 | @item @code{check?} (default: @code{#t}) |
| 3968 | This Boolean indicates whether the file system needs to be checked for |
| 3969 | errors before being mounted. |
| 3970 | |
| 3971 | @item @code{create-mount-point?} (default: @code{#f}) |
| 3972 | When true, the mount point is created if it does not exist yet. |
| 3973 | |
| 3974 | @end table |
| 3975 | @end deftp |
| 3976 | |
| 3977 | The @code{(gnu system file-systems)} exports the following useful |
| 3978 | variables. |
| 3979 | |
| 3980 | @defvr {Scheme Variable} %base-file-systems |
| 3981 | These are essential file systems that are required on normal systems, |
| 3982 | such as @var{%devtmpfs-file-system} (see below.) Operating system |
| 3983 | declarations should always contain at least these. |
| 3984 | @end defvr |
| 3985 | |
| 3986 | @defvr {Scheme Variable} %devtmpfs-file-system |
| 3987 | The @code{devtmpfs} file system to be mounted on @file{/dev}. This is a |
| 3988 | requirement for udev (@pxref{Base Services, @code{udev-service}}). |
| 3989 | @end defvr |
| 3990 | |
| 3991 | @defvr {Scheme Variable} %pseudo-terminal-file-system |
| 3992 | This is the file system to be mounted as @file{/dev/pts}. It supports |
| 3993 | @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar |
| 3994 | functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference |
| 3995 | Manual}). Pseudo-terminals are used by terminal emulators such as |
| 3996 | @command{xterm}. |
| 3997 | @end defvr |
| 3998 | |
| 3999 | @defvr {Scheme Variable} %shared-memory-file-system |
| 4000 | This file system is mounted as @file{/dev/shm} and is used to support |
| 4001 | memory sharing across processes (@pxref{Memory-mapped I/O, |
| 4002 | @code{shm_open},, libc, The GNU C Library Reference Manual}). |
| 4003 | @end defvr |
| 4004 | |
| 4005 | @defvr {Scheme Variable} %binary-format-file-system |
| 4006 | The @code{binfmt_misc} file system, which allows handling of arbitrary |
| 4007 | executable file types to be delegated to user space. This requires the |
| 4008 | @code{binfmt.ko} kernel module to be loaded. |
| 4009 | @end defvr |
| 4010 | |
| 4011 | @defvr {Scheme Variable} %fuse-control-file-system |
| 4012 | The @code{fusectl} file system, which allows unprivileged users to mount |
| 4013 | and unmount user-space FUSE file systems. This requires the |
| 4014 | @code{fuse.ko} kernel module to be loaded. |
| 4015 | @end defvr |
| 4016 | |
| 4017 | @node Mapped Devices |
| 4018 | @subsection Mapped Devices |
| 4019 | |
| 4020 | @cindex device mapping |
| 4021 | @cindex mapped devices |
| 4022 | The Linux kernel has a notion of @dfn{device mapping}: a block device, |
| 4023 | such as a hard disk partition, can be @dfn{mapped} into another device, |
| 4024 | with additional processing over the data that flows through |
| 4025 | it@footnote{Note that the GNU@tie{}Hurd makes no difference between the |
| 4026 | concept of a ``mapped device'' and that of a file system: both boil down |
| 4027 | to @emph{translating} input/output operations made on a file to |
| 4028 | operations on its backing store. Thus, the Hurd implements mapped |
| 4029 | devices, like file systems, using the generic @dfn{translator} mechanism |
| 4030 | (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A |
| 4031 | typical example is encryption device mapping: all writes to the mapped |
| 4032 | device are encrypted, and all reads are deciphered, transparently. |
| 4033 | |
| 4034 | Mapped devices are declared using the @code{mapped-device} form: |
| 4035 | |
| 4036 | @example |
| 4037 | (mapped-device |
| 4038 | (source "/dev/sda3") |
| 4039 | (target "home") |
| 4040 | (type luks-device-mapping)) |
| 4041 | @end example |
| 4042 | |
| 4043 | @noindent |
| 4044 | @cindex disk encryption |
| 4045 | @cindex LUKS |
| 4046 | This example specifies a mapping from @file{/dev/sda3} to |
| 4047 | @file{/dev/mapper/home} using LUKS---the |
| 4048 | @url{http://code.google.com/p/cryptsetup,Linux Unified Key Setup}, a |
| 4049 | standard mechanism for disk encryption. The @file{/dev/mapper/home} |
| 4050 | device can then be used as the @code{device} of a @code{file-system} |
| 4051 | declaration (@pxref{File Systems}). The @code{mapped-device} form is |
| 4052 | detailed below. |
| 4053 | |
| 4054 | @deftp {Data Type} mapped-device |
| 4055 | Objects of this type represent device mappings that will be made when |
| 4056 | the system boots up. |
| 4057 | |
| 4058 | @table @code |
| 4059 | @item source |
| 4060 | This string specifies the name of the block device to be mapped, such as |
| 4061 | @code{"/dev/sda3"}. |
| 4062 | |
| 4063 | @item target |
| 4064 | This string specifies the name of the mapping to be established. For |
| 4065 | example, specifying @code{"my-partition"} will lead to the creation of |
| 4066 | the @code{"/dev/mapper/my-partition"} device. |
| 4067 | |
| 4068 | @item type |
| 4069 | This must be a @code{mapped-device-kind} object, which specifies how |
| 4070 | @var{source} is mapped to @var{target}. |
| 4071 | @end table |
| 4072 | @end deftp |
| 4073 | |
| 4074 | @defvr {Scheme Variable} luks-device-mapping |
| 4075 | This defines LUKS block device encryption using the @command{cryptsetup} |
| 4076 | command, from the same-named package. This relies on the |
| 4077 | @code{dm-crypt} Linux kernel module. |
| 4078 | @end defvr |
| 4079 | |
| 4080 | @node User Accounts |
| 4081 | @subsection User Accounts |
| 4082 | |
| 4083 | User accounts are specified with the @code{user-account} form: |
| 4084 | |
| 4085 | @example |
| 4086 | (user-account |
| 4087 | (name "alice") |
| 4088 | (group "users") |
| 4089 | (supplementary-groups '("wheel" ;allow use of sudo, etc. |
| 4090 | "audio" ;sound card |
| 4091 | "video" ;video devices such as webcams |
| 4092 | "cdrom")) ;the good ol' CD-ROM |
| 4093 | (comment "Bob's sister") |
| 4094 | (home-directory "/home/alice")) |
| 4095 | @end example |
| 4096 | |
| 4097 | @deftp {Data Type} user-account |
| 4098 | Objects of this type represent user accounts. The following members may |
| 4099 | be specified: |
| 4100 | |
| 4101 | @table @asis |
| 4102 | @item @code{name} |
| 4103 | The name of the user account. |
| 4104 | |
| 4105 | @item @code{group} |
| 4106 | This is the name (a string) or identifier (a number) of the user group |
| 4107 | this account belongs to. |
| 4108 | |
| 4109 | @item @code{supplementary-groups} (default: @code{'()}) |
| 4110 | Optionally, this can be defined as a list of group names that this |
| 4111 | account belongs to. |
| 4112 | |
| 4113 | @item @code{uid} (default: @code{#f}) |
| 4114 | This is the user ID for this account (a number), or @code{#f}. In the |
| 4115 | latter case, a number is automatically chosen by the system when the |
| 4116 | account is created. |
| 4117 | |
| 4118 | @item @code{comment} (default: @code{""}) |
| 4119 | A comment about the account, such as the account's owner full name. |
| 4120 | |
| 4121 | @item @code{home-directory} |
| 4122 | This is the name of the home directory for the account. |
| 4123 | |
| 4124 | @item @code{shell} (default: Bash) |
| 4125 | This is a G-expression denoting the file name of a program to be used as |
| 4126 | the shell (@pxref{G-Expressions}). |
| 4127 | |
| 4128 | @item @code{system?} (default: @code{#f}) |
| 4129 | This Boolean value indicates whether the account is a ``system'' |
| 4130 | account. System accounts are sometimes treated specially; for instance, |
| 4131 | graphical login managers do not list them. |
| 4132 | |
| 4133 | @item @code{password} (default: @code{#f}) |
| 4134 | You would normally leave this field to @code{#f}, initialize user |
| 4135 | passwords as @code{root} with the @command{passwd} command, and then let |
| 4136 | users change it with @command{passwd}. |
| 4137 | |
| 4138 | If you @emph{do} want to have a preset password for an account, then |
| 4139 | this field must contain the encrypted password, as a string. |
| 4140 | @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information |
| 4141 | on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference |
| 4142 | Manual}, for information on Guile's @code{crypt} procedure. |
| 4143 | |
| 4144 | @end table |
| 4145 | @end deftp |
| 4146 | |
| 4147 | User group declarations are even simpler: |
| 4148 | |
| 4149 | @example |
| 4150 | (user-group (name "students")) |
| 4151 | @end example |
| 4152 | |
| 4153 | @deftp {Data Type} user-group |
| 4154 | This type is for, well, user groups. There are just a few fields: |
| 4155 | |
| 4156 | @table @asis |
| 4157 | @item @code{name} |
| 4158 | The group's name. |
| 4159 | |
| 4160 | @item @code{id} (default: @code{#f}) |
| 4161 | The group identifier (a number). If @code{#f}, a new number is |
| 4162 | automatically allocated when the group is created. |
| 4163 | |
| 4164 | @item @code{system?} (default: @code{#f}) |
| 4165 | This Boolean value indicates whether the group is a ``system'' group. |
| 4166 | System groups have low numerical IDs. |
| 4167 | |
| 4168 | @item @code{password} (default: @code{#f}) |
| 4169 | What, user groups can have a password? Well, apparently yes. Unless |
| 4170 | @code{#f}, this field specifies the group's password. |
| 4171 | |
| 4172 | @end table |
| 4173 | @end deftp |
| 4174 | |
| 4175 | For convenience, a variable lists all the basic user groups one may |
| 4176 | expect: |
| 4177 | |
| 4178 | @defvr {Scheme Variable} %base-groups |
| 4179 | This is the list of basic user groups that users and/or packages expect |
| 4180 | to be present on the system. This includes groups such as ``root'', |
| 4181 | ``wheel'', and ``users'', as well as groups used to control access to |
| 4182 | specific devices such as ``audio'', ``disk'', and ``cdrom''. |
| 4183 | @end defvr |
| 4184 | |
| 4185 | @node Locales |
| 4186 | @subsection Locales |
| 4187 | |
| 4188 | @cindex locale |
| 4189 | A @dfn{locale} defines cultural conventions for a particular language |
| 4190 | and region of the world (@pxref{Locales,,, libc, The GNU C Library |
| 4191 | Reference Manual}). Each locale has a name that typically has the form |
| 4192 | @code{@var{language}_@var{territory}.@var{charset}}---e.g., |
| 4193 | @code{fr_LU.utf8} designates the locale for the French language, with |
| 4194 | cultural conventions from Luxembourg, and using the UTF-8 encoding. |
| 4195 | |
| 4196 | @cindex locale definition |
| 4197 | Usually, you will want to specify the default locale for the machine |
| 4198 | using the @code{locale} field of the @code{operating-system} declaration |
| 4199 | (@pxref{operating-system Reference, @code{locale}}). |
| 4200 | |
| 4201 | That locale must be among the @dfn{locale definitions} that are known to |
| 4202 | the system---and these are specified in the @code{locale-definitions} |
| 4203 | slot of @code{operating-system}. The default value includes locale |
| 4204 | definition for some widely used locales, but not for all the available |
| 4205 | locales, in order to save space. |
| 4206 | |
| 4207 | If the locale specified in the @code{locale} field is not among the |
| 4208 | definitions listed in @code{locale-definitions}, @command{guix system} |
| 4209 | raises an error. In that case, you should add the locale definition to |
| 4210 | the @code{locale-definitions} field. For instance, to add the North |
| 4211 | Frisian locale for Germany, the value of that field may be: |
| 4212 | |
| 4213 | @example |
| 4214 | (cons (locale-definition |
| 4215 | (name "fy_DE.utf8") (source "fy_DE")) |
| 4216 | %default-locale-definitions) |
| 4217 | @end example |
| 4218 | |
| 4219 | Likewise, to save space, one might want @code{locale-definitions} to |
| 4220 | list only the locales that are actually used, as in: |
| 4221 | |
| 4222 | @example |
| 4223 | (list (locale-definition |
| 4224 | (name "ja_JP.eucjp") (source "ja_JP") |
| 4225 | (charset "EUC-JP"))) |
| 4226 | @end example |
| 4227 | |
| 4228 | The @code{locale-definition} form is provided by the @code{(gnu system |
| 4229 | locale)} module. Details are given below. |
| 4230 | |
| 4231 | @deftp {Data Type} locale-definition |
| 4232 | This is the data type of a locale definition. |
| 4233 | |
| 4234 | @table @asis |
| 4235 | |
| 4236 | @item @code{name} |
| 4237 | The name of the locale. @xref{Locale Names,,, libc, The GNU C Library |
| 4238 | Reference Manual}, for more information on locale names. |
| 4239 | |
| 4240 | @item @code{source} |
| 4241 | The name of the source for that locale. This is typically the |
| 4242 | @code{@var{language}_@var{territory}} part of the locale name. |
| 4243 | |
| 4244 | @item @code{charset} (default: @code{"UTF-8"}) |
| 4245 | The ``character set'' or ``code set'' for that locale, |
| 4246 | @uref{http://www.iana.org/assignments/character-sets, as defined by |
| 4247 | IANA}. |
| 4248 | |
| 4249 | @end table |
| 4250 | @end deftp |
| 4251 | |
| 4252 | @defvr {Scheme Variable} %default-locale-definitions |
| 4253 | An arbitrary list of commonly used locales, used as the default value of |
| 4254 | the @code{locale-definitions} field of @code{operating-system} |
| 4255 | declarations. |
| 4256 | @end defvr |
| 4257 | |
| 4258 | @node Services |
| 4259 | @subsection Services |
| 4260 | |
| 4261 | @cindex system services |
| 4262 | An important part of preparing an @code{operating-system} declaration is |
| 4263 | listing @dfn{system services} and their configuration (@pxref{Using the |
| 4264 | Configuration System}). System services are typically daemons launched |
| 4265 | when the system boots, or other actions needed at that time---e.g., |
| 4266 | configuring network access. |
| 4267 | |
| 4268 | Services are managed by GNU@tie{}dmd (@pxref{Introduction,,, dmd, GNU |
| 4269 | dmd Manual}). On a running system, the @command{deco} command allows |
| 4270 | you to list the available services, show their status, start and stop |
| 4271 | them, or do other specific operations (@pxref{Jump Start,,, dmd, GNU dmd |
| 4272 | Manual}). For example: |
| 4273 | |
| 4274 | @example |
| 4275 | # deco status dmd |
| 4276 | @end example |
| 4277 | |
| 4278 | The above command, run as @code{root}, lists the currently defined |
| 4279 | services. The @command{deco doc} command shows a synopsis of the given |
| 4280 | service: |
| 4281 | |
| 4282 | @example |
| 4283 | # deco doc nscd |
| 4284 | Run libc's name service cache daemon (nscd). |
| 4285 | @end example |
| 4286 | |
| 4287 | The @command{start}, @command{stop}, and @command{restart} sub-commands |
| 4288 | have the effect you would expect. For instance, the commands below stop |
| 4289 | the nscd service and restart the Xorg display server: |
| 4290 | |
| 4291 | @example |
| 4292 | # deco stop nscd |
| 4293 | Service nscd has been stopped. |
| 4294 | # deco restart xorg-server |
| 4295 | Service xorg-server has been stopped. |
| 4296 | Service xorg-server has been started. |
| 4297 | @end example |
| 4298 | |
| 4299 | The following sections document the available services, starting with |
| 4300 | the core services, that may be used in an @code{operating-system} |
| 4301 | declaration. |
| 4302 | |
| 4303 | @menu |
| 4304 | * Base Services:: Essential system services. |
| 4305 | * Networking Services:: Network setup, SSH daemon, etc. |
| 4306 | * X Window:: Graphical display. |
| 4307 | @end menu |
| 4308 | |
| 4309 | @node Base Services |
| 4310 | @subsubsection Base Services |
| 4311 | |
| 4312 | The @code{(gnu services base)} module provides definitions for the basic |
| 4313 | services that one expects from the system. The services exported by |
| 4314 | this module are listed below. |
| 4315 | |
| 4316 | @defvr {Scheme Variable} %base-services |
| 4317 | This variable contains a list of basic services@footnote{Technically, |
| 4318 | this is a list of monadic services. @xref{The Store Monad}.} one would |
| 4319 | expect from the system: a login service (mingetty) on each tty, syslogd, |
| 4320 | libc's name service cache daemon (nscd), the udev device manager, and |
| 4321 | more. |
| 4322 | |
| 4323 | This is the default value of the @code{services} field of |
| 4324 | @code{operating-system} declarations. Usually, when customizing a |
| 4325 | system, you will want to append services to @var{%base-services}, like |
| 4326 | this: |
| 4327 | |
| 4328 | @example |
| 4329 | (cons* (avahi-service) (lsh-service) %base-services) |
| 4330 | @end example |
| 4331 | @end defvr |
| 4332 | |
| 4333 | @deffn {Monadic Procedure} host-name-service @var{name} |
| 4334 | Return a service that sets the host name to @var{name}. |
| 4335 | @end deffn |
| 4336 | |
| 4337 | @deffn {Monadic Procedure} mingetty-service @var{tty} [#:motd] @ |
| 4338 | [#:auto-login #f] [#:login-program] [#:login-pause? #f] @ |
| 4339 | [#:allow-empty-passwords? #f] |
| 4340 | Return a service to run mingetty on @var{tty}. |
| 4341 | |
| 4342 | When @var{allow-empty-passwords?} is true, allow empty log-in password. When |
| 4343 | @var{auto-login} is true, it must be a user name under which to log-in |
| 4344 | automatically. @var{login-pause?} can be set to @code{#t} in conjunction with |
| 4345 | @var{auto-login}, in which case the user will have to press a key before the |
| 4346 | login shell is launched. |
| 4347 | |
| 4348 | When true, @var{login-program} is a gexp or a monadic gexp denoting the name |
| 4349 | of the log-in program (the default is the @code{login} program from the Shadow |
| 4350 | tool suite.) |
| 4351 | |
| 4352 | @var{motd} is a monadic value containing a text file to use as |
| 4353 | the ``message of the day''. |
| 4354 | @end deffn |
| 4355 | |
| 4356 | @cindex name service cache daemon |
| 4357 | @cindex nscd |
| 4358 | @deffn {Monadic Procedure} nscd-service [@var{config}] [#:glibc glibc] @ |
| 4359 | [#:name-services '()] |
| 4360 | Return a service that runs libc's name service cache daemon (nscd) with |
| 4361 | the given @var{config}---an @code{<nscd-configuration>} object. |
| 4362 | Optionally, @code{#:name-services} is a list of packages that provide |
| 4363 | name service switch (NSS) modules needed by nscd. |
| 4364 | @end deffn |
| 4365 | |
| 4366 | @defvr {Scheme Variable} %nscd-default-configuration |
| 4367 | This is the default @code{<nscd-configuration>} value (see below) used |
| 4368 | by @code{nscd-service}. This uses the caches defined by |
| 4369 | @var{%nscd-default-caches}; see below. |
| 4370 | @end defvr |
| 4371 | |
| 4372 | @deftp {Data Type} nscd-configuration |
| 4373 | This is the type representing the name service cache daemon (nscd) |
| 4374 | configuration. |
| 4375 | |
| 4376 | @table @asis |
| 4377 | |
| 4378 | @item @code{log-file} (default: @code{"/var/log/nscd.log"}) |
| 4379 | Name of nscd's log file. This is where debugging output goes when |
| 4380 | @code{debug-level} is strictly positive. |
| 4381 | |
| 4382 | @item @code{debug-level} (default: @code{0}) |
| 4383 | Integer denoting the debugging levels. Higher numbers mean more |
| 4384 | debugging output is logged. |
| 4385 | |
| 4386 | @item @code{caches} (default: @var{%nscd-default-caches}) |
| 4387 | List of @code{<nscd-cache>} objects denoting things to be cached; see |
| 4388 | below. |
| 4389 | |
| 4390 | @end table |
| 4391 | @end deftp |
| 4392 | |
| 4393 | @deftp {Data Type} nscd-cache |
| 4394 | Data type representing a cache database of nscd and its parameters. |
| 4395 | |
| 4396 | @table @asis |
| 4397 | |
| 4398 | @item @code{database} |
| 4399 | This is a symbol representing the name of the database to be cached. |
| 4400 | Valid values are @code{passwd}, @code{group}, @code{hosts}, and |
| 4401 | @code{services}, which designate the corresponding NSS database |
| 4402 | (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}). |
| 4403 | |
| 4404 | @item @code{positive-time-to-live} |
| 4405 | @itemx @code{negative-time-to-live} (default: @code{20}) |
| 4406 | A number representing the number of seconds during which a positive or |
| 4407 | negative lookup result remains in cache. |
| 4408 | |
| 4409 | @item @code{check-files?} (default: @code{#t}) |
| 4410 | Whether to check for updates of the files corresponding to |
| 4411 | @var{database}. |
| 4412 | |
| 4413 | For instance, when @var{database} is @code{hosts}, setting this flag |
| 4414 | instructs nscd to check for updates in @file{/etc/hosts} and to take |
| 4415 | them into account. |
| 4416 | |
| 4417 | @item @code{persistent?} (default: @code{#t}) |
| 4418 | Whether the cache should be stored persistently on disk. |
| 4419 | |
| 4420 | @item @code{shared?} (default: @code{#t}) |
| 4421 | Whether the cache should be shared among users. |
| 4422 | |
| 4423 | @item @code{max-database-size} (default: 32@tie{}MiB) |
| 4424 | Maximum size in bytes of the database cache. |
| 4425 | |
| 4426 | @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert |
| 4427 | @c settings, so leave them out. |
| 4428 | |
| 4429 | @end table |
| 4430 | @end deftp |
| 4431 | |
| 4432 | @defvr {Scheme Variable} %nscd-default-caches |
| 4433 | List of @code{<nscd-cache>} objects used by default by |
| 4434 | @code{nscd-configuration} (see above.) |
| 4435 | |
| 4436 | It enables persistent and aggressive caching of service and host name |
| 4437 | lookups. The latter provides better host name lookup performance, |
| 4438 | resilience in the face of unreliable name servers, and also better |
| 4439 | privacy---often the result of host name lookups is in local cache, so |
| 4440 | external name servers do not even need to be queried. |
| 4441 | @end defvr |
| 4442 | |
| 4443 | |
| 4444 | @deffn {Monadic Procedure} syslog-service |
| 4445 | Return a service that runs @code{syslogd} with reasonable default |
| 4446 | settings. |
| 4447 | @end deffn |
| 4448 | |
| 4449 | @deffn {Monadic Procedure} guix-service [#:guix guix] @ |
| 4450 | [#:builder-group "guixbuild"] [#:build-accounts 10] @ |
| 4451 | [#:authorize-hydra-key? #t] [#:use-substitutes? #t] @ |
| 4452 | [#:extra-options '()] |
| 4453 | Return a service that runs the build daemon from @var{guix}, and has |
| 4454 | @var{build-accounts} user accounts available under @var{builder-group}. |
| 4455 | |
| 4456 | When @var{authorize-hydra-key?} is true, the @code{hydra.gnu.org} public key |
| 4457 | provided by @var{guix} is authorized upon activation, meaning that substitutes |
| 4458 | from @code{hydra.gnu.org} are used by default. |
| 4459 | |
| 4460 | If @var{use-substitutes?} is false, the daemon is run with |
| 4461 | @option{--no-substitutes} (@pxref{Invoking guix-daemon, |
| 4462 | @option{--no-substitutes}}). |
| 4463 | |
| 4464 | Finally, @var{extra-options} is a list of additional command-line options |
| 4465 | passed to @command{guix-daemon}. |
| 4466 | @end deffn |
| 4467 | |
| 4468 | @deffn {Monadic Procedure} udev-service [#:udev udev] |
| 4469 | Run @var{udev}, which populates the @file{/dev} directory dynamically. |
| 4470 | @end deffn |
| 4471 | |
| 4472 | |
| 4473 | @node Networking Services |
| 4474 | @subsubsection Networking Services |
| 4475 | |
| 4476 | The @code{(gnu services networking)} module provides services to configure |
| 4477 | the network interface. |
| 4478 | |
| 4479 | @cindex DHCP, networking service |
| 4480 | @deffn {Monadic Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}] |
| 4481 | Return a service that runs @var{dhcp}, a Dynamic Host Configuration |
| 4482 | Protocol (DHCP) client, on all the non-loopback network interfaces. |
| 4483 | @end deffn |
| 4484 | |
| 4485 | @deffn {Monadic Procedure} static-networking-service @var{interface} @var{ip} @ |
| 4486 | [#:gateway #f] [#:name-services @code{'()}] |
| 4487 | Return a service that starts @var{interface} with address @var{ip}. If |
| 4488 | @var{gateway} is true, it must be a string specifying the default network |
| 4489 | gateway. |
| 4490 | @end deffn |
| 4491 | |
| 4492 | @cindex wicd |
| 4493 | @deffn {Monadic Procedure} wicd-service [#:wicd @var{wicd}] |
| 4494 | Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a |
| 4495 | network manager that aims to simplify wired and wireless networking. |
| 4496 | @end deffn |
| 4497 | |
| 4498 | @deffn {Monadic Procedure} ntp-service [#:ntp @var{ntp}] @ |
| 4499 | [#:name-service @var{%ntp-servers}] |
| 4500 | Return a service that runs the daemon from @var{ntp}, the |
| 4501 | @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will |
| 4502 | keep the system clock synchronized with that of @var{servers}. |
| 4503 | @end deffn |
| 4504 | |
| 4505 | @defvr {Scheme Variable} %ntp-servers |
| 4506 | List of host names used as the default NTP servers. |
| 4507 | @end defvr |
| 4508 | |
| 4509 | @deffn {Monadic Procedure} tor-service [#:tor tor] |
| 4510 | Return a service to run the @uref{https://torproject.org,Tor} daemon. |
| 4511 | |
| 4512 | The daemon runs with the default settings (in particular the default exit |
| 4513 | policy) as the @code{tor} unprivileged user. |
| 4514 | @end deffn |
| 4515 | |
| 4516 | @deffn {Monadic Procedure} bitlbee-service [#:bitlbee bitlbee] @ |
| 4517 | [#:interface "127.0.0.1"] [#:port 6667] @ |
| 4518 | [#:extra-settings ""] |
| 4519 | Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that |
| 4520 | acts as a gateway between IRC and chat networks. |
| 4521 | |
| 4522 | The daemon will listen to the interface corresponding to the IP address |
| 4523 | specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only |
| 4524 | local clients can connect, whereas @code{0.0.0.0} means that connections can |
| 4525 | come from any networking interface. |
| 4526 | |
| 4527 | In addition, @var{extra-settings} specifies a string to append to the |
| 4528 | configuration file. |
| 4529 | @end deffn |
| 4530 | |
| 4531 | Furthermore, @code{(gnu services ssh)} provides the following service. |
| 4532 | |
| 4533 | @deffn {Monadic Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @ |
| 4534 | [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @ |
| 4535 | [#:allow-empty-passwords? #f] [#:root-login? #f] @ |
| 4536 | [#:syslog-output? #t] [#:x11-forwarding? #t] @ |
| 4537 | [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @ |
| 4538 | [#:public-key-authentication? #t] [#:initialize? #f] |
| 4539 | Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}. |
| 4540 | @var{host-key} must designate a file containing the host key, and readable |
| 4541 | only by root. |
| 4542 | |
| 4543 | When @var{daemonic?} is true, @command{lshd} will detach from the |
| 4544 | controlling terminal and log its output to syslogd, unless one sets |
| 4545 | @var{syslog-output?} to false. Obviously, it also makes lsh-service |
| 4546 | depend on existence of syslogd service. When @var{pid-file?} is true, |
| 4547 | @command{lshd} writes its PID to the file called @var{pid-file}. |
| 4548 | |
| 4549 | When @var{initialize?} is true, automatically create the seed and host key |
| 4550 | upon service activation if they do not exist yet. This may take long and |
| 4551 | require interaction. |
| 4552 | |
| 4553 | When @var{initialize?} is false, it is up to the user to initialize the |
| 4554 | randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create |
| 4555 | a key pair with the private key stored in file @var{host-key} (@pxref{lshd |
| 4556 | basics,,, lsh, LSH Manual}). |
| 4557 | |
| 4558 | When @var{interfaces} is empty, lshd listens for connections on all the |
| 4559 | network interfaces; otherwise, @var{interfaces} must be a list of host names |
| 4560 | or addresses. |
| 4561 | |
| 4562 | @var{allow-empty-passwords?} specifies whether to accept log-ins with empty |
| 4563 | passwords, and @var{root-login?} specifies whether to accept log-ins as |
| 4564 | root. |
| 4565 | |
| 4566 | The other options should be self-descriptive. |
| 4567 | @end deffn |
| 4568 | |
| 4569 | @defvr {Scheme Variable} %facebook-host-aliases |
| 4570 | This variable contains a string for use in @file{/etc/hosts} |
| 4571 | (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each |
| 4572 | line contains a entry that maps a known server name of the Facebook |
| 4573 | on-line service---e.g., @code{www.facebook.com}---to the local |
| 4574 | host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}. |
| 4575 | |
| 4576 | This variable is typically used in the @code{hosts-file} field of an |
| 4577 | @code{operating-system} declaration (@pxref{operating-system Reference, |
| 4578 | @file{/etc/hosts}}): |
| 4579 | |
| 4580 | @example |
| 4581 | (use-modules (gnu) (guix)) |
| 4582 | |
| 4583 | (operating-system |
| 4584 | (host-name "mymachine") |
| 4585 | ;; ... |
| 4586 | (hosts-file |
| 4587 | ;; Create a /etc/hosts file with aliases for "localhost" |
| 4588 | ;; and "mymachine", as well as for Facebook servers. |
| 4589 | (text-file "hosts" |
| 4590 | (string-append (local-host-aliases host-name) |
| 4591 | %facebook-host-aliases)))) |
| 4592 | @end example |
| 4593 | |
| 4594 | This mechanism can prevent programs running locally, such as Web |
| 4595 | browsers, from accessing Facebook. |
| 4596 | @end defvr |
| 4597 | |
| 4598 | @node X Window |
| 4599 | @subsubsection X Window |
| 4600 | |
| 4601 | Support for the X Window graphical display system---specifically |
| 4602 | Xorg---is provided by the @code{(gnu services xorg)} module. Note that |
| 4603 | there is no @code{xorg-service} procedure. Instead, the X server is |
| 4604 | started by the @dfn{login manager}, currently SLiM. |
| 4605 | |
| 4606 | @deffn {Monadic Procedure} slim-service [#:allow-empty-passwords? #f] @ |
| 4607 | [#:auto-login? #f] [#:default-user ""] [#:startx] @ |
| 4608 | [#:theme @var{%default-slim-theme}] @ |
| 4609 | [#:theme-name @var{%default-slim-theme-name}] @ |
| 4610 | [#:sessions @var{%default-sessions}] |
| 4611 | Return a service that spawns the SLiM graphical login manager, which in |
| 4612 | turn starts the X display server with @var{startx}, a command as returned by |
| 4613 | @code{xorg-start-command}. |
| 4614 | |
| 4615 | When @var{allow-empty-passwords?} is true, allow logins with an empty |
| 4616 | password. When @var{auto-login?} is true, log in automatically as |
| 4617 | @var{default-user}. |
| 4618 | |
| 4619 | If @var{theme} is @code{#f}, the use the default log-in theme; otherwise |
| 4620 | @var{theme} must be a gexp denoting the name of a directory containing the |
| 4621 | theme to use. In that case, @var{theme-name} specifies the name of the |
| 4622 | theme. |
| 4623 | |
| 4624 | Last, @var{session} is a list of @code{<session-type>} objects denoting the |
| 4625 | available session types that can be chosen from the log-in screen. |
| 4626 | @end deffn |
| 4627 | |
| 4628 | @defvr {Scheme Variable} %default-sessions |
| 4629 | The list of default session types used by SLiM. |
| 4630 | @end defvr |
| 4631 | |
| 4632 | @defvr {Scheme Variable} %ratpoison-session-type |
| 4633 | Session type using the Ratpoison window manager. |
| 4634 | @end defvr |
| 4635 | |
| 4636 | @defvr {Scheme Variable} %windowmaker-session-type |
| 4637 | Session type using the WindowMaker window manager. |
| 4638 | @end defvr |
| 4639 | |
| 4640 | @defvr {Scheme Variable} %sawfish-session-type |
| 4641 | Session type using the Sawfish window manager. |
| 4642 | @end defvr |
| 4643 | |
| 4644 | @defvr {Scheme Variable} %default-theme |
| 4645 | @defvrx {Scheme Variable} %default-theme-name |
| 4646 | The G-Expression denoting the default SLiM theme and its name. |
| 4647 | @end defvr |
| 4648 | |
| 4649 | @deffn {Monadic Procedure} xorg-start-command [#:guile] @ |
| 4650 | [#:drivers '()] [#:resolutions '()] [#:xorg-server @var{xorg-server}] |
| 4651 | Return a derivation that builds a @var{guile} script to start the X server |
| 4652 | from @var{xorg-server}. Usually the X server is started by a login manager. |
| 4653 | |
| 4654 | @var{drivers} must be either the empty list, in which case Xorg chooses a |
| 4655 | graphics driver automatically, or a list of driver names that will be tried in |
| 4656 | this order---e.g., @code{("modesetting" "vesa")}. |
| 4657 | |
| 4658 | Likewise, when @var{resolutions} is the empty list, Xorg chooses an |
| 4659 | appropriate screen resolution; otherwise, it must be a list of |
| 4660 | resolutions---e.g., @code{((1024 768) (640 480))}. |
| 4661 | @end deffn |
| 4662 | |
| 4663 | @node Setuid Programs |
| 4664 | @subsection Setuid Programs |
| 4665 | |
| 4666 | @cindex setuid programs |
| 4667 | Some programs need to run with ``root'' privileges, even when they are |
| 4668 | launched by unprivileged users. A notorious example is the |
| 4669 | @command{passwd} programs, which can users can run to change their |
| 4670 | password, and which requires write access to the @file{/etc/passwd} and |
| 4671 | @file{/etc/shadow} files---something normally restricted to root, for |
| 4672 | obvious security reasons. To address that, these executables are |
| 4673 | @dfn{setuid-root}, meaning that they always run with root privileges |
| 4674 | (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual}, |
| 4675 | for more info about the setuid mechanisms.) |
| 4676 | |
| 4677 | The store itself @emph{cannot} contain setuid programs: that would be a |
| 4678 | security issue since any user on the system can write derivations that |
| 4679 | populate the store (@pxref{The Store}). Thus, a different mechanism is |
| 4680 | used: instead of changing the setuid bit directly on files that are in |
| 4681 | the store, we let the system administrator @emph{declare} which programs |
| 4682 | should be setuid root. |
| 4683 | |
| 4684 | The @code{setuid-programs} field of an @code{operating-system} |
| 4685 | declaration contains a list of G-expressions denoting the names of |
| 4686 | programs to be setuid-root (@pxref{Using the Configuration System}). |
| 4687 | For instance, the @command{passwd} program, which is part of the Shadow |
| 4688 | package, can be designated by this G-expression (@pxref{G-Expressions}): |
| 4689 | |
| 4690 | @example |
| 4691 | #~(string-append #$shadow "/bin/passwd") |
| 4692 | @end example |
| 4693 | |
| 4694 | A default set of setuid programs is defined by the |
| 4695 | @code{%setuid-programs} variable of the @code{(gnu system)} module. |
| 4696 | |
| 4697 | @defvr {Scheme Variable} %setuid-programs |
| 4698 | A list of G-expressions denoting common programs that are setuid-root. |
| 4699 | |
| 4700 | The list includes commands such as @command{passwd}, @command{ping}, |
| 4701 | @command{su}, and @command{sudo}. |
| 4702 | @end defvr |
| 4703 | |
| 4704 | Under the hood, the actual setuid programs are created in the |
| 4705 | @file{/run/setuid-programs} directory at system activation time. The |
| 4706 | files in this directory refer to the ``real'' binaries, which are in the |
| 4707 | store. |
| 4708 | |
| 4709 | @node Name Service Switch |
| 4710 | @subsection Name Service Switch |
| 4711 | |
| 4712 | @cindex name service switch |
| 4713 | @cindex NSS |
| 4714 | The @code{(gnu system nss)} module provides bindings to the |
| 4715 | configuration file of libc's @dfn{name service switch} or @dfn{NSS} |
| 4716 | (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference |
| 4717 | Manual}). In a nutshell, the NSS is a mechanism that allows libc to be |
| 4718 | extended with new ``name'' lookup methods for system databases, which |
| 4719 | includes host names, service names, user accounts, and more (@pxref{Name |
| 4720 | Service Switch, System Databases and Name Service Switch,, libc, The GNU |
| 4721 | C Library Reference Manual}). |
| 4722 | |
| 4723 | The NSS configuration specifies, for each system database, which lookup |
| 4724 | method is to be used, and how the various methods are chained |
| 4725 | together---for instance, under which circumstances NSS should try the |
| 4726 | next method in the list. The NSS configuration is given in the |
| 4727 | @code{name-service-switch} field of @code{operating-system} declarations |
| 4728 | (@pxref{operating-system Reference, @code{name-service-switch}}). |
| 4729 | |
| 4730 | @c See <http://0pointer.de/lennart/projects/nss-mdns/>. |
| 4731 | As an example, the declaration below configures the NSS to use the |
| 4732 | @code{nss-mdns} back-end for host name lookups: |
| 4733 | |
| 4734 | @example |
| 4735 | (name-service-switch |
| 4736 | (hosts (list %files ;first, check /etc/hosts |
| 4737 | |
| 4738 | ;; If the above did not succeed, try |
| 4739 | ;; with 'mdns_minimal'. |
| 4740 | (name-service |
| 4741 | (name "mdns_minimal") |
| 4742 | |
| 4743 | ;; 'mdns_minimal' is authoritative for |
| 4744 | ;; '.local'. When it returns "not found", |
| 4745 | ;; no need to try the next methods. |
| 4746 | (reaction (lookup-specification |
| 4747 | (not-found => return)))) |
| 4748 | |
| 4749 | ;; Then fall back to DNS. |
| 4750 | (name-service |
| 4751 | (name "dns")) |
| 4752 | |
| 4753 | ;; Finally, try with the "full" 'mdns'. |
| 4754 | (name-service |
| 4755 | (name "mdns"))))) |
| 4756 | @end example |
| 4757 | |
| 4758 | The reference for name service switch configuration is given below. It |
| 4759 | is a direct mapping of the C library's configuration file format, so |
| 4760 | please refer to the C library manual for more information (@pxref{NSS |
| 4761 | Configuration File,,, libc, The GNU C Library Reference Manual}). |
| 4762 | Compared to libc's NSS configuration file format, it has the advantage |
| 4763 | not only of adding this warm parenthetic feel that we like, but also |
| 4764 | static checks: you'll know about syntax errors and typos as soon as you |
| 4765 | run @command{guix system}. |
| 4766 | |
| 4767 | @defvr {Scheme Variable} %default-nss |
| 4768 | This is the default name service switch configuration, a |
| 4769 | @code{name-service-switch} object. |
| 4770 | @end defvr |
| 4771 | |
| 4772 | @deftp {Data Type} name-service-switch |
| 4773 | |
| 4774 | This is the data type representation the configuration of libc's name |
| 4775 | service switch (NSS). Each field below represents one of the supported |
| 4776 | system databases. |
| 4777 | |
| 4778 | @table @code |
| 4779 | @item aliases |
| 4780 | @itemx ethers |
| 4781 | @itemx group |
| 4782 | @itemx gshadow |
| 4783 | @itemx hosts |
| 4784 | @itemx initgroups |
| 4785 | @itemx netgroup |
| 4786 | @itemx networks |
| 4787 | @itemx password |
| 4788 | @itemx public-key |
| 4789 | @itemx rpc |
| 4790 | @itemx services |
| 4791 | @itemx shadow |
| 4792 | The system databases handled by the NSS. Each of these fields must be a |
| 4793 | list of @code{<name-service>} objects (see below.) |
| 4794 | @end table |
| 4795 | @end deftp |
| 4796 | |
| 4797 | @deftp {Data Type} name-service |
| 4798 | |
| 4799 | This is the data type representing an actual name service and the |
| 4800 | associated lookup action. |
| 4801 | |
| 4802 | @table @code |
| 4803 | @item name |
| 4804 | A string denoting the name service (@pxref{Services in the NSS |
| 4805 | configuration,,, libc, The GNU C Library Reference Manual}). |
| 4806 | |
| 4807 | Note that name services listed here must be visible to nscd. This is |
| 4808 | achieved by passing the @code{#:name-services} argument to |
| 4809 | @code{nscd-service} the list of packages providing the needed name |
| 4810 | services (@pxref{Base Services, @code{nscd-service}}). |
| 4811 | |
| 4812 | @item reaction |
| 4813 | An action specified using the @code{lookup-specification} macro |
| 4814 | (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library |
| 4815 | Reference Manual}). For example: |
| 4816 | |
| 4817 | @example |
| 4818 | (lookup-specification (unavailable => continue) |
| 4819 | (success => return)) |
| 4820 | @end example |
| 4821 | @end table |
| 4822 | @end deftp |
| 4823 | |
| 4824 | @node Initial RAM Disk |
| 4825 | @subsection Initial RAM Disk |
| 4826 | |
| 4827 | @cindex initial RAM disk (initrd) |
| 4828 | @cindex initrd (initial RAM disk) |
| 4829 | For bootstrapping purposes, the Linux-Libre kernel is passed an |
| 4830 | @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary |
| 4831 | root file system, as well as an initialization script. The latter is |
| 4832 | responsible for mounting the real root file system, and for loading any |
| 4833 | kernel modules that may be needed to achieve that. |
| 4834 | |
| 4835 | The @code{initrd} field of an @code{operating-system} declaration allows |
| 4836 | you to specify which initrd you would like to use. The @code{(gnu |
| 4837 | system linux-initrd)} module provides two ways to build an initrd: the |
| 4838 | high-level @code{base-initrd} procedure, and the low-level |
| 4839 | @code{expression->initrd} procedure. |
| 4840 | |
| 4841 | The @code{base-initrd} procedure is intended to cover most common uses. |
| 4842 | For example, if you want to add a bunch of kernel modules to be loaded |
| 4843 | at boot time, you can define the @code{initrd} field of the operating |
| 4844 | system declaration like this: |
| 4845 | |
| 4846 | @example |
| 4847 | (initrd (lambda (file-systems . rest) |
| 4848 | ;; Create a standard initrd that has modules "foo.ko" |
| 4849 | ;; and "bar.ko", as well as their dependencies, in |
| 4850 | ;; addition to the modules available by default. |
| 4851 | (apply base-initrd file-systems |
| 4852 | #:extra-modules '("foo" "bar") |
| 4853 | rest))) |
| 4854 | @end example |
| 4855 | |
| 4856 | The @code{base-initrd} procedure also handles common use cases that |
| 4857 | involves using the system as a QEMU guest, or as a ``live'' system whose |
| 4858 | root file system is volatile. |
| 4859 | |
| 4860 | @deffn {Monadic Procedure} base-initrd @var{file-systems} @ |
| 4861 | [#:qemu-networking? #f] [#:virtio? #f] [#:volatile-root? #f] @ |
| 4862 | [#:extra-modules '()] [#:mapped-devices '()] |
| 4863 | Return a monadic derivation that builds a generic initrd. @var{file-systems} is |
| 4864 | a list of file-systems to be mounted by the initrd, possibly in addition to |
| 4865 | the root file system specified on the kernel command line via @code{--root}. |
| 4866 | @var{mapped-devices} is a list of device mappings to realize before |
| 4867 | @var{file-systems} are mounted (@pxref{Mapped Devices}). |
| 4868 | |
| 4869 | When @var{qemu-networking?} is true, set up networking with the standard QEMU |
| 4870 | parameters. When @var{virtio?} is true, load additional modules so the initrd can |
| 4871 | be used as a QEMU guest with para-virtualized I/O drivers. |
| 4872 | |
| 4873 | When @var{volatile-root?} is true, the root file system is writable but any changes |
| 4874 | to it are lost. |
| 4875 | |
| 4876 | The initrd is automatically populated with all the kernel modules necessary |
| 4877 | for @var{file-systems} and for the given options. However, additional kernel |
| 4878 | modules can be listed in @var{extra-modules}. They will be added to the initrd, and |
| 4879 | loaded at boot time in the order in which they appear. |
| 4880 | @end deffn |
| 4881 | |
| 4882 | Needless to say, the initrds we produce and use embed a |
| 4883 | statically-linked Guile, and the initialization program is a Guile |
| 4884 | program. That gives a lot of flexibility. The |
| 4885 | @code{expression->initrd} procedure builds such an initrd, given the |
| 4886 | program to run in that initrd. |
| 4887 | |
| 4888 | @deffn {Monadic Procedure} expression->initrd @var{exp} @ |
| 4889 | [#:guile %guile-static-stripped] [#:name "guile-initrd"] @ |
| 4890 | [#:modules '()] |
| 4891 | Return a derivation that builds a Linux initrd (a gzipped cpio archive) |
| 4892 | containing @var{guile} and that evaluates @var{exp}, a G-expression, |
| 4893 | upon booting. All the derivations referenced by @var{exp} are |
| 4894 | automatically copied to the initrd. |
| 4895 | |
| 4896 | @var{modules} is a list of Guile module names to be embedded in the |
| 4897 | initrd. |
| 4898 | @end deffn |
| 4899 | |
| 4900 | @node GRUB Configuration |
| 4901 | @subsection GRUB Configuration |
| 4902 | |
| 4903 | @cindex GRUB |
| 4904 | @cindex boot loader |
| 4905 | |
| 4906 | The operating system uses GNU@tie{}GRUB as its boot loader |
| 4907 | (@pxref{Overview, overview of GRUB,, grub, GNU GRUB Manual}). It is |
| 4908 | configured using @code{grub-configuration} declarations. This data type |
| 4909 | is exported by the @code{(gnu system grub)} module, and described below. |
| 4910 | |
| 4911 | @deftp {Data Type} grub-configuration |
| 4912 | The type of a GRUB configuration declaration. |
| 4913 | |
| 4914 | @table @asis |
| 4915 | |
| 4916 | @item @code{device} |
| 4917 | This is a string denoting the boot device. It must be a device name |
| 4918 | understood by the @command{grub-install} command, such as |
| 4919 | @code{/dev/sda} or @code{(hd0)} (@pxref{Invoking grub-install,,, grub, |
| 4920 | GNU GRUB Manual}). |
| 4921 | |
| 4922 | @item @code{menu-entries} (default: @code{()}) |
| 4923 | A possibly empty list of @code{menu-entry} objects (see below), denoting |
| 4924 | entries to appear in the GRUB boot menu, in addition to the current |
| 4925 | system entry and the entry pointing to previous system generations. |
| 4926 | |
| 4927 | @item @code{default-entry} (default: @code{0}) |
| 4928 | The index of the default boot menu entry. Index 0 is for the current |
| 4929 | system's entry. |
| 4930 | |
| 4931 | @item @code{timeout} (default: @code{5}) |
| 4932 | The number of seconds to wait for keyboard input before booting. Set to |
| 4933 | 0 to boot immediately, and to -1 to wait indefinitely. |
| 4934 | |
| 4935 | @item @code{theme} (default: @var{%default-theme}) |
| 4936 | The @code{grub-theme} object describing the theme to use. |
| 4937 | @end table |
| 4938 | |
| 4939 | @end deftp |
| 4940 | |
| 4941 | Should you want to list additional boot menu entries @i{via} the |
| 4942 | @code{menu-entries} field above, you will need to create them with the |
| 4943 | @code{menu-entry} form: |
| 4944 | |
| 4945 | @deftp {Data Type} menu-entry |
| 4946 | The type of an entry in the GRUB boot menu. |
| 4947 | |
| 4948 | @table @asis |
| 4949 | |
| 4950 | @item @code{label} |
| 4951 | The label to show in the menu---e.g., @code{"GNU"}. |
| 4952 | |
| 4953 | @item @code{linux} |
| 4954 | The Linux kernel to boot. |
| 4955 | |
| 4956 | @item @code{linux-arguments} (default: @code{()}) |
| 4957 | The list of extra Linux kernel command-line arguments---e.g., |
| 4958 | @code{("console=ttyS0")}. |
| 4959 | |
| 4960 | @item @code{initrd} |
| 4961 | A G-Expression or string denoting the file name of the initial RAM disk |
| 4962 | to use (@pxref{G-Expressions}). |
| 4963 | |
| 4964 | @end table |
| 4965 | @end deftp |
| 4966 | |
| 4967 | @c FIXME: Write documentation once it's stable. |
| 4968 | Themes are created using the @code{grub-theme} form, which is not |
| 4969 | documented yet. |
| 4970 | |
| 4971 | @defvr {Scheme Variable} %default-theme |
| 4972 | This is the default GRUB theme used by the operating system, with a |
| 4973 | fancy background image displaying the GNU and Guix logos. |
| 4974 | @end defvr |
| 4975 | |
| 4976 | |
| 4977 | @node Invoking guix system |
| 4978 | @subsection Invoking @code{guix system} |
| 4979 | |
| 4980 | Once you have written an operating system declaration, as seen in the |
| 4981 | previous section, it can be @dfn{instantiated} using the @command{guix |
| 4982 | system} command. The synopsis is: |
| 4983 | |
| 4984 | @example |
| 4985 | guix system @var{options}@dots{} @var{action} @var{file} |
| 4986 | @end example |
| 4987 | |
| 4988 | @var{file} must be the name of a file containing an |
| 4989 | @code{operating-system} declaration. @var{action} specifies how the |
| 4990 | operating system is instantiate. Currently the following values are |
| 4991 | supported: |
| 4992 | |
| 4993 | @table @code |
| 4994 | @item reconfigure |
| 4995 | Build the operating system described in @var{file}, activate it, and |
| 4996 | switch to it@footnote{This action is usable only on systems already |
| 4997 | running GNU.}. |
| 4998 | |
| 4999 | This effects all the configuration specified in @var{file}: user |
| 5000 | accounts, system services, global package list, setuid programs, etc. |
| 5001 | |
| 5002 | It also adds a GRUB menu entry for the new OS configuration, and moves |
| 5003 | entries for older configurations to a submenu---unless |
| 5004 | @option{--no-grub} is passed. |
| 5005 | |
| 5006 | @c The paragraph below refers to the problem discussed at |
| 5007 | @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>. |
| 5008 | It is highly recommended to run @command{guix pull} once before you run |
| 5009 | @command{guix system reconfigure} for the first time (@pxref{Invoking |
| 5010 | guix pull}). Failing to do that you would see an older version of Guix |
| 5011 | once @command{reconfigure} has completed. |
| 5012 | |
| 5013 | @item build |
| 5014 | Build the operating system's derivation, which includes all the |
| 5015 | configuration files and programs needed to boot and run the system. |
| 5016 | This action does not actually install anything. |
| 5017 | |
| 5018 | @item init |
| 5019 | Populate the given directory with all the files necessary to run the |
| 5020 | operating system specified in @var{file}. This is useful for first-time |
| 5021 | installations of GSD. For instance: |
| 5022 | |
| 5023 | @example |
| 5024 | guix system init my-os-config.scm /mnt |
| 5025 | @end example |
| 5026 | |
| 5027 | copies to @file{/mnt} all the store items required by the configuration |
| 5028 | specified in @file{my-os-config.scm}. This includes configuration |
| 5029 | files, packages, and so on. It also creates other essential files |
| 5030 | needed for the system to operate correctly---e.g., the @file{/etc}, |
| 5031 | @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file. |
| 5032 | |
| 5033 | This command also installs GRUB on the device specified in |
| 5034 | @file{my-os-config}, unless the @option{--no-grub} option was passed. |
| 5035 | |
| 5036 | @item vm |
| 5037 | @cindex virtual machine |
| 5038 | @cindex VM |
| 5039 | Build a virtual machine that contain the operating system declared in |
| 5040 | @var{file}, and return a script to run that virtual machine (VM). |
| 5041 | Arguments given to the script are passed as is to QEMU. |
| 5042 | |
| 5043 | The VM shares its store with the host system. |
| 5044 | |
| 5045 | Additional file systems can be shared between the host and the VM using |
| 5046 | the @code{--share} and @code{--expose} command-line options: the former |
| 5047 | specifies a directory to be shared with write access, while the latter |
| 5048 | provides read-only access to the shared directory. |
| 5049 | |
| 5050 | The example below creates a VM in which the user's home directory is |
| 5051 | accessible read-only, and where the @file{/exchange} directory is a |
| 5052 | read-write mapping of the host's @file{$HOME/tmp}: |
| 5053 | |
| 5054 | @example |
| 5055 | guix system vm my-config.scm \ |
| 5056 | --expose=$HOME --share=$HOME/tmp=/exchange |
| 5057 | @end example |
| 5058 | |
| 5059 | On GNU/Linux, the default is to boot directly to the kernel; this has |
| 5060 | the advantage of requiring only a very tiny root disk image since the |
| 5061 | host's store can then be mounted. |
| 5062 | |
| 5063 | The @code{--full-boot} option forces a complete boot sequence, starting |
| 5064 | with the bootloader. This requires more disk space since a root image |
| 5065 | containing at least the kernel, initrd, and bootloader data files must |
| 5066 | be created. The @code{--image-size} option can be used to specify the |
| 5067 | image's size. |
| 5068 | |
| 5069 | @item vm-image |
| 5070 | @itemx disk-image |
| 5071 | Return a virtual machine or disk image of the operating system declared |
| 5072 | in @var{file} that stands alone. Use the @option{--image-size} option |
| 5073 | to specify the size of the image. |
| 5074 | |
| 5075 | When using @code{vm-image}, the returned image is in qcow2 format, which |
| 5076 | the QEMU emulator can efficiently use. |
| 5077 | |
| 5078 | When using @code{disk-image}, a raw disk image is produced; it can be |
| 5079 | copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is |
| 5080 | the device corresponding to a USB stick, one can copy the image on it |
| 5081 | using the following command: |
| 5082 | |
| 5083 | @example |
| 5084 | # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc |
| 5085 | @end example |
| 5086 | |
| 5087 | @end table |
| 5088 | |
| 5089 | @var{options} can contain any of the common build options provided by |
| 5090 | @command{guix build} (@pxref{Invoking guix build}). In addition, |
| 5091 | @var{options} can contain one of the following: |
| 5092 | |
| 5093 | @table @option |
| 5094 | @item --system=@var{system} |
| 5095 | @itemx -s @var{system} |
| 5096 | Attempt to build for @var{system} instead of the host's system type. |
| 5097 | This works as per @command{guix build} (@pxref{Invoking guix build}). |
| 5098 | |
| 5099 | @item --image-size=@var{size} |
| 5100 | For the @code{vm-image} and @code{disk-image} actions, create an image |
| 5101 | of the given @var{size}. @var{size} may be a number of bytes, or it may |
| 5102 | include a unit as a suffix (@pxref{Block size, size specifications,, |
| 5103 | coreutils, GNU Coreutils}). |
| 5104 | @end table |
| 5105 | |
| 5106 | Note that all the actions above, except @code{build} and @code{init}, |
| 5107 | rely on KVM support in the Linux-Libre kernel. Specifically, the |
| 5108 | machine should have hardware virtualization support, the corresponding |
| 5109 | KVM kernel module should be loaded, and the @file{/dev/kvm} device node |
| 5110 | must exist and be readable and writable by the user and by the daemon's |
| 5111 | build users. |
| 5112 | |
| 5113 | @node Defining Services |
| 5114 | @subsection Defining Services |
| 5115 | |
| 5116 | The @code{(gnu services @dots{})} modules define several procedures that allow |
| 5117 | users to declare the operating system's services (@pxref{Using the |
| 5118 | Configuration System}). These procedures are @emph{monadic |
| 5119 | procedures}---i.e., procedures that return a monadic value in the store |
| 5120 | monad (@pxref{The Store Monad}). For examples of such procedures, |
| 5121 | @xref{Services}. |
| 5122 | |
| 5123 | @cindex service definition |
| 5124 | The monadic value returned by those procedures is a @dfn{service |
| 5125 | definition}---a structure as returned by the @code{service} form. |
| 5126 | Service definitions specifies the inputs the service depends on, and an |
| 5127 | expression to start and stop the service. Behind the scenes, service |
| 5128 | definitions are ``translated'' into the form suitable for the |
| 5129 | configuration file of dmd, the init system (@pxref{Services,,, dmd, GNU |
| 5130 | dmd Manual}). |
| 5131 | |
| 5132 | As an example, here is what the @code{nscd-service} procedure looks |
| 5133 | like: |
| 5134 | |
| 5135 | @lisp |
| 5136 | (define (nscd-service) |
| 5137 | (with-monad %store-monad |
| 5138 | (return (service |
| 5139 | (documentation "Run libc's name service cache daemon.") |
| 5140 | (provision '(nscd)) |
| 5141 | (activate #~(begin |
| 5142 | (use-modules (guix build utils)) |
| 5143 | (mkdir-p "/var/run/nscd"))) |
| 5144 | (start #~(make-forkexec-constructor |
| 5145 | (string-append #$glibc "/sbin/nscd") |
| 5146 | "-f" "/dev/null" "--foreground")) |
| 5147 | (stop #~(make-kill-destructor)) |
| 5148 | (respawn? #f))))) |
| 5149 | @end lisp |
| 5150 | |
| 5151 | @noindent |
| 5152 | The @code{activate}, @code{start}, and @code{stop} fields are G-expressions |
| 5153 | (@pxref{G-Expressions}). The @code{activate} field contains a script to |
| 5154 | run at ``activation'' time; it makes sure that the @file{/var/run/nscd} |
| 5155 | directory exists before @command{nscd} is started. |
| 5156 | |
| 5157 | The @code{start} and @code{stop} fields refer to dmd's facilities to |
| 5158 | start and stop processes (@pxref{Service De- and Constructors,,, dmd, |
| 5159 | GNU dmd Manual}). The @code{provision} field specifies the name under |
| 5160 | which this service is known to dmd, and @code{documentation} specifies |
| 5161 | on-line documentation. Thus, the commands @command{deco start ncsd}, |
| 5162 | @command{deco stop nscd}, and @command{deco doc nscd} will do what you |
| 5163 | would expect (@pxref{Invoking deco,,, dmd, GNU dmd Manual}). |
| 5164 | |
| 5165 | |
| 5166 | @node Installing Debugging Files |
| 5167 | @section Installing Debugging Files |
| 5168 | |
| 5169 | @cindex debugging files |
| 5170 | Program binaries, as produced by the GCC compilers for instance, are |
| 5171 | typically written in the ELF format, with a section containing |
| 5172 | @dfn{debugging information}. Debugging information is what allows the |
| 5173 | debugger, GDB, to map binary code to source code; it is required to |
| 5174 | debug a compiled program in good conditions. |
| 5175 | |
| 5176 | The problem with debugging information is that is takes up a fair amount |
| 5177 | of disk space. For example, debugging information for the GNU C Library |
| 5178 | weighs in at more than 60 MiB. Thus, as a user, keeping all the |
| 5179 | debugging info of all the installed programs is usually not an option. |
| 5180 | Yet, space savings should not come at the cost of an impediment to |
| 5181 | debugging---especially in the GNU system, which should make it easier |
| 5182 | for users to exert their computing freedom (@pxref{GNU Distribution}). |
| 5183 | |
| 5184 | Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a |
| 5185 | mechanism that allows users to get the best of both worlds: debugging |
| 5186 | information can be stripped from the binaries and stored in separate |
| 5187 | files. GDB is then able to load debugging information from those files, |
| 5188 | when they are available (@pxref{Separate Debug Files,,, gdb, Debugging |
| 5189 | with GDB}). |
| 5190 | |
| 5191 | The GNU distribution takes advantage of this by storing debugging |
| 5192 | information in the @code{lib/debug} sub-directory of a separate package |
| 5193 | output unimaginatively called @code{debug} (@pxref{Packages with |
| 5194 | Multiple Outputs}). Users can choose to install the @code{debug} output |
| 5195 | of a package when they need it. For instance, the following command |
| 5196 | installs the debugging information for the GNU C Library and for GNU |
| 5197 | Guile: |
| 5198 | |
| 5199 | @example |
| 5200 | guix package -i glibc:debug guile:debug |
| 5201 | @end example |
| 5202 | |
| 5203 | GDB must then be told to look for debug files in the user's profile, by |
| 5204 | setting the @code{debug-file-directory} variable (consider setting it |
| 5205 | from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with |
| 5206 | GDB}): |
| 5207 | |
| 5208 | @example |
| 5209 | (gdb) set debug-file-directory ~/.guix-profile/lib/debug |
| 5210 | @end example |
| 5211 | |
| 5212 | From there on, GDB will pick up debugging information from the |
| 5213 | @code{.debug} files under @file{~/.guix-profile/lib/debug}. |
| 5214 | |
| 5215 | In addition, you will most likely want GDB to be able to show the source |
| 5216 | code being debugged. To do that, you will have to unpack the source |
| 5217 | code of the package of interest (obtained with @code{guix build |
| 5218 | --source}, @pxref{Invoking guix build}), and to point GDB to that source |
| 5219 | directory using the @code{directory} command (@pxref{Source Path, |
| 5220 | @code{directory},, gdb, Debugging with GDB}). |
| 5221 | |
| 5222 | @c XXX: keep me up-to-date |
| 5223 | The @code{debug} output mechanism in Guix is implemented by the |
| 5224 | @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is |
| 5225 | opt-in---debugging information is available only for those packages |
| 5226 | whose definition explicitly declares a @code{debug} output. This may be |
| 5227 | changed to opt-out in the future, if our build farm servers can handle |
| 5228 | the load. To check whether a package has a @code{debug} output, use |
| 5229 | @command{guix package --list-available} (@pxref{Invoking guix package}). |
| 5230 | |
| 5231 | |
| 5232 | @node Security Updates |
| 5233 | @section Security Updates |
| 5234 | |
| 5235 | @quotation Note |
| 5236 | As of version @value{VERSION}, the feature described in this section is |
| 5237 | experimental. |
| 5238 | @end quotation |
| 5239 | |
| 5240 | @cindex security updates |
| 5241 | Occasionally, important security vulnerabilities are discovered in core |
| 5242 | software packages and must be patched. Guix follows a functional |
| 5243 | package management discipline (@pxref{Introduction}), which implies |
| 5244 | that, when a package is changed, @emph{every package that depends on it} |
| 5245 | must be rebuilt. This can significantly slow down the deployment of |
| 5246 | fixes in core packages such as libc or Bash, since basically the whole |
| 5247 | distribution would need to be rebuilt. Using pre-built binaries helps |
| 5248 | (@pxref{Substitutes}), but deployment may still take more time than |
| 5249 | desired. |
| 5250 | |
| 5251 | @cindex grafts |
| 5252 | To address that, Guix implements @dfn{grafts}, a mechanism that allows |
| 5253 | for fast deployment of critical updates without the costs associated |
| 5254 | with a whole-distribution rebuild. The idea is to rebuild only the |
| 5255 | package that needs to be patched, and then to ``graft'' it onto packages |
| 5256 | explicitly installed by the user and that were previously referring to |
| 5257 | the original package. The cost of grafting is typically very low, and |
| 5258 | order of magnitudes lower than a full rebuild of the dependency chain. |
| 5259 | |
| 5260 | @cindex replacements of packages, for grafts |
| 5261 | For instance, suppose a security update needs to be applied to Bash. |
| 5262 | Guix developers will provide a package definition for the ``fixed'' |
| 5263 | Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining |
| 5264 | Packages}). Then, the original package definition is augmented with a |
| 5265 | @code{replacement} field pointing to the package containing the bug fix: |
| 5266 | |
| 5267 | @example |
| 5268 | (define bash |
| 5269 | (package |
| 5270 | (name "bash") |
| 5271 | ;; @dots{} |
| 5272 | (replacement bash-fixed))) |
| 5273 | @end example |
| 5274 | |
| 5275 | From there on, any package depending directly or indirectly on Bash that |
| 5276 | is installed will automatically be ``rewritten'' to refer to |
| 5277 | @var{bash-fixed} instead of @var{bash}. This grafting process takes |
| 5278 | time proportional to the size of the package, but expect less than a |
| 5279 | minute for an ``average'' package on a recent machine. |
| 5280 | |
| 5281 | Currently, the graft and the package it replaces (@var{bash-fixed} and |
| 5282 | @var{bash} in the example above) must have the exact same @code{name} |
| 5283 | and @code{version} fields. This restriction mostly comes from the fact |
| 5284 | that grafting works by patching files, including binary files, directly. |
| 5285 | Other restrictions may apply: for instance, when adding a graft to a |
| 5286 | package providing a shared library, the original shared library and its |
| 5287 | replacement must have the same @code{SONAME} and be binary-compatible. |
| 5288 | |
| 5289 | |
| 5290 | @node Package Modules |
| 5291 | @section Package Modules |
| 5292 | |
| 5293 | From a programming viewpoint, the package definitions of the |
| 5294 | GNU distribution are provided by Guile modules in the @code{(gnu packages |
| 5295 | @dots{})} name space@footnote{Note that packages under the @code{(gnu |
| 5296 | packages @dots{})} module name space are not necessarily ``GNU |
| 5297 | packages''. This module naming scheme follows the usual Guile module |
| 5298 | naming convention: @code{gnu} means that these modules are distributed |
| 5299 | as part of the GNU system, and @code{packages} identifies modules that |
| 5300 | define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile |
| 5301 | Reference Manual}). For instance, the @code{(gnu packages emacs)} |
| 5302 | module exports a variable named @code{emacs}, which is bound to a |
| 5303 | @code{<package>} object (@pxref{Defining Packages}). |
| 5304 | |
| 5305 | The @code{(gnu packages @dots{})} module name space is |
| 5306 | automatically scanned for packages by the command-line tools. For |
| 5307 | instance, when running @code{guix package -i emacs}, all the @code{(gnu |
| 5308 | packages @dots{})} modules are scanned until one that exports a package |
| 5309 | object whose name is @code{emacs} is found. This package search |
| 5310 | facility is implemented in the @code{(gnu packages)} module. |
| 5311 | |
| 5312 | @cindex customization, of packages |
| 5313 | @cindex package module search path |
| 5314 | Users can store package definitions in modules with different |
| 5315 | names---e.g., @code{(my-packages emacs)}. These package definitions |
| 5316 | will not be visible by default. Thus, users can invoke commands such as |
| 5317 | @command{guix package} and @command{guix build} have to be used with the |
| 5318 | @code{-e} option so that they know where to find the package, or use the |
| 5319 | @code{-L} option of these commands to make those modules visible |
| 5320 | (@pxref{Invoking guix build, @code{--load-path}}), or define the |
| 5321 | @code{GUIX_PACKAGE_PATH} environment variable. This environment |
| 5322 | variable makes it easy to extend or customize the distribution and is |
| 5323 | honored by all the user interfaces. |
| 5324 | |
| 5325 | @defvr {Environment Variable} GUIX_PACKAGE_PATH |
| 5326 | This is a colon-separated list of directories to search for package |
| 5327 | modules. Directories listed in this variable take precedence over the |
| 5328 | distribution's own modules. |
| 5329 | @end defvr |
| 5330 | |
| 5331 | The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}: |
| 5332 | each package is built based solely on other packages in the |
| 5333 | distribution. The root of this dependency graph is a small set of |
| 5334 | @dfn{bootstrap binaries}, provided by the @code{(gnu packages |
| 5335 | bootstrap)} module. For more information on bootstrapping, |
| 5336 | @pxref{Bootstrapping}. |
| 5337 | |
| 5338 | @node Packaging Guidelines |
| 5339 | @section Packaging Guidelines |
| 5340 | |
| 5341 | The GNU distribution is nascent and may well lack some of your favorite |
| 5342 | packages. This section describes how you can help make the distribution |
| 5343 | grow. @xref{Contributing}, for additional information on how you can |
| 5344 | help. |
| 5345 | |
| 5346 | Free software packages are usually distributed in the form of |
| 5347 | @dfn{source code tarballs}---typically @file{tar.gz} files that contain |
| 5348 | all the source files. Adding a package to the distribution means |
| 5349 | essentially two things: adding a @dfn{recipe} that describes how to |
| 5350 | build the package, including a list of other packages required to build |
| 5351 | it, and adding @dfn{package meta-data} along with that recipe, such as a |
| 5352 | description and licensing information. |
| 5353 | |
| 5354 | In Guix all this information is embodied in @dfn{package definitions}. |
| 5355 | Package definitions provide a high-level view of the package. They are |
| 5356 | written using the syntax of the Scheme programming language; in fact, |
| 5357 | for each package we define a variable bound to the package definition, |
| 5358 | and export that variable from a module (@pxref{Package Modules}). |
| 5359 | However, in-depth Scheme knowledge is @emph{not} a prerequisite for |
| 5360 | creating packages. For more information on package definitions, |
| 5361 | @pxref{Defining Packages}. |
| 5362 | |
| 5363 | Once a package definition is in place, stored in a file in the Guix |
| 5364 | source tree, it can be tested using the @command{guix build} command |
| 5365 | (@pxref{Invoking guix build}). For example, assuming the new package is |
| 5366 | called @code{gnew}, you may run this command from the Guix build tree: |
| 5367 | |
| 5368 | @example |
| 5369 | ./pre-inst-env guix build gnew --keep-failed |
| 5370 | @end example |
| 5371 | |
| 5372 | Using @code{--keep-failed} makes it easier to debug build failures since |
| 5373 | it provides access to the failed build tree. Another useful |
| 5374 | command-line option when debugging is @code{--log-file}, to access the |
| 5375 | build log. |
| 5376 | |
| 5377 | If the package is unknown to the @command{guix} command, it may be that |
| 5378 | the source file contains a syntax error, or lacks a @code{define-public} |
| 5379 | clause to export the package variable. To figure it out, you may load |
| 5380 | the module from Guile to get more information about the actual error: |
| 5381 | |
| 5382 | @example |
| 5383 | ./pre-inst-env guile -c '(use-modules (gnu packages gnew))' |
| 5384 | @end example |
| 5385 | |
| 5386 | Once your package builds correctly, please send us a patch |
| 5387 | (@pxref{Contributing}). Well, if you need help, we will be happy to |
| 5388 | help you too. Once the patch is committed in the Guix repository, the |
| 5389 | new package automatically gets built on the supported platforms by |
| 5390 | @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration |
| 5391 | system}. |
| 5392 | |
| 5393 | @cindex substituter |
| 5394 | Users can obtain the new package definition simply by running |
| 5395 | @command{guix pull} (@pxref{Invoking guix pull}). When |
| 5396 | @code{hydra.gnu.org} is done building the package, installing the |
| 5397 | package automatically downloads binaries from there |
| 5398 | (@pxref{Substitutes}). The only place where human intervention is |
| 5399 | needed is to review and apply the patch. |
| 5400 | |
| 5401 | |
| 5402 | @menu |
| 5403 | * Software Freedom:: What may go into the distribution. |
| 5404 | * Package Naming:: What's in a name? |
| 5405 | * Version Numbers:: When the name is not enough. |
| 5406 | * Python Modules:: Taming the snake. |
| 5407 | * Perl Modules:: Little pearls. |
| 5408 | * Fonts:: Fond of fonts. |
| 5409 | @end menu |
| 5410 | |
| 5411 | @node Software Freedom |
| 5412 | @subsection Software Freedom |
| 5413 | |
| 5414 | @c Adapted from http://www.gnu.org/philosophy/philosophy.html. |
| 5415 | |
| 5416 | The GNU operating system has been developed so that users can have |
| 5417 | freedom in their computing. GNU is @dfn{free software}, meaning that |
| 5418 | users have the @url{http://www.gnu.org/philosophy/free-sw.html,four |
| 5419 | essential freedoms}: to run the program, to study and change the program |
| 5420 | in source code form, to redistribute exact copies, and to distribute |
| 5421 | modified versions. Packages found in the GNU distribution provide only |
| 5422 | software that conveys these four freedoms. |
| 5423 | |
| 5424 | In addition, the GNU distribution follow the |
| 5425 | @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free |
| 5426 | software distribution guidelines}. Among other things, these guidelines |
| 5427 | reject non-free firmware, recommendations of non-free software, and |
| 5428 | discuss ways to deal with trademarks and patents. |
| 5429 | |
| 5430 | Some packages contain a small and optional subset that violates the |
| 5431 | above guidelines, for instance because this subset is itself non-free |
| 5432 | code. When that happens, the offending items are removed with |
| 5433 | appropriate patches or code snippets in the package definition's |
| 5434 | @code{origin} form (@pxref{Defining Packages}). That way, @code{guix |
| 5435 | build --source} returns the ``freed'' source rather than the unmodified |
| 5436 | upstream source. |
| 5437 | |
| 5438 | |
| 5439 | @node Package Naming |
| 5440 | @subsection Package Naming |
| 5441 | |
| 5442 | A package has actually two names associated with it: |
| 5443 | First, there is the name of the @emph{Scheme variable}, the one following |
| 5444 | @code{define-public}. By this name, the package can be made known in the |
| 5445 | Scheme code, for instance as input to another package. Second, there is |
| 5446 | the string in the @code{name} field of a package definition. This name |
| 5447 | is used by package management commands such as |
| 5448 | @command{guix package} and @command{guix build}. |
| 5449 | |
| 5450 | Both are usually the same and correspond to the lowercase conversion of |
| 5451 | the project name chosen upstream, with underscores replaced with |
| 5452 | hyphens. For instance, GNUnet is available as @code{gnunet}, and |
| 5453 | SDL_net as @code{sdl-net}. |
| 5454 | |
| 5455 | We do not add @code{lib} prefixes for library packages, unless these are |
| 5456 | already part of the official project name. But @pxref{Python |
| 5457 | Modules} and @ref{Perl Modules} for special rules concerning modules for |
| 5458 | the Python and Perl languages. |
| 5459 | |
| 5460 | Font package names are handled differently, @pxref{Fonts}. |
| 5461 | |
| 5462 | |
| 5463 | @node Version Numbers |
| 5464 | @subsection Version Numbers |
| 5465 | |
| 5466 | We usually package only the latest version of a given free software |
| 5467 | project. But sometimes, for instance for incompatible library versions, |
| 5468 | two (or more) versions of the same package are needed. These require |
| 5469 | different Scheme variable names. We use the name as defined |
| 5470 | in @ref{Package Naming} |
| 5471 | for the most recent version; previous versions use the same name, suffixed |
| 5472 | by @code{-} and the smallest prefix of the version number that may |
| 5473 | distinguish the two versions. |
| 5474 | |
| 5475 | The name inside the package definition is the same for all versions of a |
| 5476 | package and does not contain any version number. |
| 5477 | |
| 5478 | For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows: |
| 5479 | |
| 5480 | @example |
| 5481 | (define-public gtk+ |
| 5482 | (package |
| 5483 | (name "gtk+") |
| 5484 | (version "3.9.12") |
| 5485 | ...)) |
| 5486 | (define-public gtk+-2 |
| 5487 | (package |
| 5488 | (name "gtk+") |
| 5489 | (version "2.24.20") |
| 5490 | ...)) |
| 5491 | @end example |
| 5492 | If we also wanted GTK+ 3.8.2, this would be packaged as |
| 5493 | @example |
| 5494 | (define-public gtk+-3.8 |
| 5495 | (package |
| 5496 | (name "gtk+") |
| 5497 | (version "3.8.2") |
| 5498 | ...)) |
| 5499 | @end example |
| 5500 | |
| 5501 | |
| 5502 | @node Python Modules |
| 5503 | @subsection Python Modules |
| 5504 | |
| 5505 | We currently package Python 2 and Python 3, under the Scheme variable names |
| 5506 | @code{python-2} and @code{python} as explained in @ref{Version Numbers}. |
| 5507 | To avoid confusion and naming clashes with other programming languages, it |
| 5508 | seems desirable that the name of a package for a Python module contains |
| 5509 | the word @code{python}. |
| 5510 | |
| 5511 | Some modules are compatible with only one version of Python, others with both. |
| 5512 | If the package Foo compiles only with Python 3, we name it |
| 5513 | @code{python-foo}; if it compiles only with Python 2, we name it |
| 5514 | @code{python2-foo}. If it is compatible with both versions, we create two |
| 5515 | packages with the corresponding names. |
| 5516 | |
| 5517 | If a project already contains the word @code{python}, we drop this; |
| 5518 | for instance, the module python-dateutil is packaged under the names |
| 5519 | @code{python-dateutil} and @code{python2-dateutil}. |
| 5520 | |
| 5521 | |
| 5522 | @node Perl Modules |
| 5523 | @subsection Perl Modules |
| 5524 | |
| 5525 | Perl programs standing for themselves are named as any other package, |
| 5526 | using the lowercase upstream name. |
| 5527 | For Perl packages containing a single class, we use the lowercase class name, |
| 5528 | replace all occurrences of @code{::} by dashes and prepend the prefix |
| 5529 | @code{perl-}. |
| 5530 | So the class @code{XML::Parser} becomes @code{perl-xml-parser}. |
| 5531 | Modules containing several classes keep their lowercase upstream name and |
| 5532 | are also prepended by @code{perl-}. Such modules tend to have the word |
| 5533 | @code{perl} somewhere in their name, which gets dropped in favor of the |
| 5534 | prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}. |
| 5535 | |
| 5536 | |
| 5537 | @node Fonts |
| 5538 | @subsection Fonts |
| 5539 | |
| 5540 | For fonts that are in general not installed by a user for typesetting |
| 5541 | purposes, or that are distributed as part of a larger software package, |
| 5542 | we rely on the general packaging rules for software; for instance, this |
| 5543 | applies to the fonts delivered as part of the X.Org system or fonts that |
| 5544 | are part of TeX Live. |
| 5545 | |
| 5546 | To make it easier for a user to search for fonts, names for other packages |
| 5547 | containing only fonts are constructed as follows, independently of the |
| 5548 | upstream package name. |
| 5549 | |
| 5550 | The name of a package containing only one font family starts with |
| 5551 | @code{font-}; it is followed by the foundry name and a dash @code{-} |
| 5552 | if the foundry is known, and the font family name, in which spaces are |
| 5553 | replaced by dashes (and as usual, all upper case letters are transformed |
| 5554 | to lower case). |
| 5555 | For example, the Gentium font family by SIL is packaged under the name |
| 5556 | @code{font-sil-gentium}. |
| 5557 | |
| 5558 | For a package containing several font families, the name of the collection |
| 5559 | is used in the place of the font family name. |
| 5560 | For instance, the Liberation fonts consist of three families, |
| 5561 | Liberation Sans, Liberation Serif and Liberation Mono. |
| 5562 | These could be packaged separately under the names |
| 5563 | @code{font-liberation-sans} and so on; but as they are distributed together |
| 5564 | under a common name, we prefer to package them together as |
| 5565 | @code{font-liberation}. |
| 5566 | |
| 5567 | In the case where several formats of the same font family or font collection |
| 5568 | are packaged separately, a short form of the format, prepended by a dash, |
| 5569 | is added to the package name. We use @code{-ttf} for TrueType fonts, |
| 5570 | @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1 |
| 5571 | fonts. |
| 5572 | |
| 5573 | |
| 5574 | |
| 5575 | @node Bootstrapping |
| 5576 | @section Bootstrapping |
| 5577 | |
| 5578 | @c Adapted from the ELS 2013 paper. |
| 5579 | |
| 5580 | @cindex bootstrapping |
| 5581 | |
| 5582 | Bootstrapping in our context refers to how the distribution gets built |
| 5583 | ``from nothing''. Remember that the build environment of a derivation |
| 5584 | contains nothing but its declared inputs (@pxref{Introduction}). So |
| 5585 | there's an obvious chicken-and-egg problem: how does the first package |
| 5586 | get built? How does the first compiler get compiled? Note that this is |
| 5587 | a question of interest only to the curious hacker, not to the regular |
| 5588 | user, so you can shamelessly skip this section if you consider yourself |
| 5589 | a ``regular user''. |
| 5590 | |
| 5591 | @cindex bootstrap binaries |
| 5592 | The GNU system is primarily made of C code, with libc at its core. The |
| 5593 | GNU build system itself assumes the availability of a Bourne shell and |
| 5594 | command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and |
| 5595 | `grep'. Furthermore, build programs---programs that run |
| 5596 | @code{./configure}, @code{make}, etc.---are written in Guile Scheme |
| 5597 | (@pxref{Derivations}). Consequently, to be able to build anything at |
| 5598 | all, from scratch, Guix relies on pre-built binaries of Guile, GCC, |
| 5599 | Binutils, libc, and the other packages mentioned above---the |
| 5600 | @dfn{bootstrap binaries}. |
| 5601 | |
| 5602 | These bootstrap binaries are ``taken for granted'', though we can also |
| 5603 | re-create them if needed (more on that later). |
| 5604 | |
| 5605 | @unnumberedsubsec Preparing to Use the Bootstrap Binaries |
| 5606 | |
| 5607 | @c As of Emacs 24.3, Info-mode displays the image, but since it's a |
| 5608 | @c large image, it's hard to scroll. Oh well. |
| 5609 | @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations} |
| 5610 | |
| 5611 | The figure above shows the very beginning of the dependency graph of the |
| 5612 | distribution, corresponding to the package definitions of the @code{(gnu |
| 5613 | packages bootstrap)} module. At this level of detail, things are |
| 5614 | slightly complex. First, Guile itself consists of an ELF executable, |
| 5615 | along with many source and compiled Scheme files that are dynamically |
| 5616 | loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz} |
| 5617 | tarball shown in this graph. This tarball is part of Guix's ``source'' |
| 5618 | distribution, and gets inserted into the store with @code{add-to-store} |
| 5619 | (@pxref{The Store}). |
| 5620 | |
| 5621 | But how do we write a derivation that unpacks this tarball and adds it |
| 5622 | to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv} |
| 5623 | derivation---the first one that gets built---uses @code{bash} as its |
| 5624 | builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls |
| 5625 | @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar}, |
| 5626 | @file{xz}, and @file{mkdir} are statically-linked binaries, also part of |
| 5627 | the Guix source distribution, whose sole purpose is to allow the Guile |
| 5628 | tarball to be unpacked. |
| 5629 | |
| 5630 | Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning |
| 5631 | Guile that can be used to run subsequent build programs. Its first task |
| 5632 | is to download tarballs containing the other pre-built binaries---this |
| 5633 | is what the @code{.tar.xz.drv} derivations do. Guix modules such as |
| 5634 | @code{ftp-client.scm} are used for this purpose. The |
| 5635 | @code{module-import.drv} derivations import those modules in a directory |
| 5636 | in the store, using the original layout. The |
| 5637 | @code{module-import-compiled.drv} derivations compile those modules, and |
| 5638 | write them in an output directory with the right layout. This |
| 5639 | corresponds to the @code{#:modules} argument of |
| 5640 | @code{build-expression->derivation} (@pxref{Derivations}). |
| 5641 | |
| 5642 | Finally, the various tarballs are unpacked by the |
| 5643 | derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv}, |
| 5644 | etc., at which point we have a working C tool chain. |
| 5645 | |
| 5646 | |
| 5647 | @unnumberedsubsec Building the Build Tools |
| 5648 | |
| 5649 | @c TODO: Add a package-level dependency graph generated from (gnu |
| 5650 | @c packages base). |
| 5651 | |
| 5652 | Bootstrapping is complete when we have a full tool chain that does not |
| 5653 | depend on the pre-built bootstrap tools discussed above. This |
| 5654 | no-dependency requirement is verified by checking whether the files of |
| 5655 | the final tool chain contain references to the @file{/gnu/store} |
| 5656 | directories of the bootstrap inputs. The process that leads to this |
| 5657 | ``final'' tool chain is described by the package definitions found in |
| 5658 | the @code{(gnu packages commencement)} module. |
| 5659 | |
| 5660 | @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>. |
| 5661 | The first tool that gets built with the bootstrap binaries is |
| 5662 | GNU Make, which is a prerequisite for all the following packages. |
| 5663 | From there Findutils and Diffutils get built. |
| 5664 | |
| 5665 | Then come the first-stage Binutils and GCC, built as pseudo cross |
| 5666 | tools---i.e., with @code{--target} equal to @code{--host}. They are |
| 5667 | used to build libc. Thanks to this cross-build trick, this libc is |
| 5668 | guaranteed not to hold any reference to the initial tool chain. |
| 5669 | |
| 5670 | From there the final Binutils and GCC are built. GCC uses @code{ld} |
| 5671 | from the final Binutils, and links programs against the just-built libc. |
| 5672 | This tool chain is used to build the other packages used by Guix and by |
| 5673 | the GNU Build System: Guile, Bash, Coreutils, etc. |
| 5674 | |
| 5675 | And voilà! At this point we have the complete set of build tools that |
| 5676 | the GNU Build System expects. These are in the @code{%final-inputs} |
| 5677 | variable of the @code{(gnu packages commencement)} module, and are |
| 5678 | implicitly used by any package that uses @code{gnu-build-system} |
| 5679 | (@pxref{Build Systems, @code{gnu-build-system}}). |
| 5680 | |
| 5681 | |
| 5682 | @unnumberedsubsec Building the Bootstrap Binaries |
| 5683 | |
| 5684 | Because the final tool chain does not depend on the bootstrap binaries, |
| 5685 | those rarely need to be updated. Nevertheless, it is useful to have an |
| 5686 | automated way to produce them, should an update occur, and this is what |
| 5687 | the @code{(gnu packages make-bootstrap)} module provides. |
| 5688 | |
| 5689 | The following command builds the tarballs containing the bootstrap |
| 5690 | binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture |
| 5691 | of Coreutils and other basic command-line tools): |
| 5692 | |
| 5693 | @example |
| 5694 | guix build bootstrap-tarballs |
| 5695 | @end example |
| 5696 | |
| 5697 | The generated tarballs are those that should be referred to in the |
| 5698 | @code{(gnu packages bootstrap)} module mentioned at the beginning of |
| 5699 | this section. |
| 5700 | |
| 5701 | Still here? Then perhaps by now you've started to wonder: when do we |
| 5702 | reach a fixed point? That is an interesting question! The answer is |
| 5703 | unknown, but if you would like to investigate further (and have |
| 5704 | significant computational and storage resources to do so), then let us |
| 5705 | know. |
| 5706 | |
| 5707 | @node Porting |
| 5708 | @section Porting to a New Platform |
| 5709 | |
| 5710 | As discussed above, the GNU distribution is self-contained, and |
| 5711 | self-containment is achieved by relying on pre-built ``bootstrap |
| 5712 | binaries'' (@pxref{Bootstrapping}). These binaries are specific to an |
| 5713 | operating system kernel, CPU architecture, and application binary |
| 5714 | interface (ABI). Thus, to port the distribution to a platform that is |
| 5715 | not yet supported, one must build those bootstrap binaries, and update |
| 5716 | the @code{(gnu packages bootstrap)} module to use them on that platform. |
| 5717 | |
| 5718 | Fortunately, Guix can @emph{cross compile} those bootstrap binaries. |
| 5719 | When everything goes well, and assuming the GNU tool chain supports the |
| 5720 | target platform, this can be as simple as running a command like this |
| 5721 | one: |
| 5722 | |
| 5723 | @example |
| 5724 | guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs |
| 5725 | @end example |
| 5726 | |
| 5727 | For this to work, the @code{glibc-dynamic-linker} procedure in |
| 5728 | @code{(gnu packages bootstrap)} must be augmented to return the right |
| 5729 | file name for libc's dynamic linker on that platform; likewise, |
| 5730 | @code{system->linux-architecture} in @code{(gnu packages linux)} must be |
| 5731 | taught about the new platform. |
| 5732 | |
| 5733 | Once these are built, the @code{(gnu packages bootstrap)} module needs |
| 5734 | to be updated to refer to these binaries on the target platform. That |
| 5735 | is, the hashes and URLs of the bootstrap tarballs for the new platform |
| 5736 | must be added alongside those of the currently supported platforms. The |
| 5737 | bootstrap Guile tarball is treated specially: it is expected to be |
| 5738 | available locally, and @file{gnu-system.am} has rules do download it for |
| 5739 | the supported architectures; a rule for the new platform must be added |
| 5740 | as well. |
| 5741 | |
| 5742 | In practice, there may be some complications. First, it may be that the |
| 5743 | extended GNU triplet that specifies an ABI (like the @code{eabi} suffix |
| 5744 | above) is not recognized by all the GNU tools. Typically, glibc |
| 5745 | recognizes some of these, whereas GCC uses an extra @code{--with-abi} |
| 5746 | configure flag (see @code{gcc.scm} for examples of how to handle this). |
| 5747 | Second, some of the required packages could fail to build for that |
| 5748 | platform. Lastly, the generated binaries could be broken for some |
| 5749 | reason. |
| 5750 | |
| 5751 | |
| 5752 | @c ********************************************************************* |
| 5753 | @node Contributing |
| 5754 | @chapter Contributing |
| 5755 | |
| 5756 | This project is a cooperative effort, and we need your help to make it |
| 5757 | grow! Please get in touch with us on @email{guix-devel@@gnu.org} and |
| 5758 | @code{#guix} on the Freenode IRC network. We welcome ideas, bug |
| 5759 | reports, patches, and anything that may be helpful to the project. We |
| 5760 | particularly welcome help on packaging (@pxref{Packaging Guidelines}). |
| 5761 | |
| 5762 | Please see the |
| 5763 | @url{http://git.savannah.gnu.org/cgit/guix.git/tree/HACKING, |
| 5764 | @file{HACKING} file} that comes with the Guix source code for practical |
| 5765 | details about contributions. |
| 5766 | |
| 5767 | |
| 5768 | @c ********************************************************************* |
| 5769 | @node Acknowledgments |
| 5770 | @chapter Acknowledgments |
| 5771 | |
| 5772 | Guix is based on the Nix package manager, which was designed and |
| 5773 | implemented by Eelco Dolstra, with contributions from other people (see |
| 5774 | the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package |
| 5775 | management, and promoted unprecedented features, such as transactional |
| 5776 | package upgrades and rollbacks, per-user profiles, and referentially |
| 5777 | transparent build processes. Without this work, Guix would not exist. |
| 5778 | |
| 5779 | The Nix-based software distributions, Nixpkgs and NixOS, have also been |
| 5780 | an inspiration for Guix. |
| 5781 | |
| 5782 | GNU@tie{}Guix itself is a collective work with contributions from a |
| 5783 | number of people. See the @file{AUTHORS} file in Guix for more |
| 5784 | information on these fine people. The @file{THANKS} file lists people |
| 5785 | who have helped by reporting bugs, taking care of the infrastructure, |
| 5786 | providing artwork and themes, making suggestions, and more---thank you! |
| 5787 | |
| 5788 | |
| 5789 | @c ********************************************************************* |
| 5790 | @node GNU Free Documentation License |
| 5791 | @appendix GNU Free Documentation License |
| 5792 | |
| 5793 | @include fdl-1.3.texi |
| 5794 | |
| 5795 | @c ********************************************************************* |
| 5796 | @node Concept Index |
| 5797 | @unnumbered Concept Index |
| 5798 | @printindex cp |
| 5799 | |
| 5800 | @node Programming Index |
| 5801 | @unnumbered Programming Index |
| 5802 | @syncodeindex tp fn |
| 5803 | @syncodeindex vr fn |
| 5804 | @printindex fn |
| 5805 | |
| 5806 | @bye |
| 5807 | |
| 5808 | @c Local Variables: |
| 5809 | @c ispell-local-dictionary: "american"; |
| 5810 | @c End: |