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-*- mode: org -*-

[[https://www.gnu.org/software/guix/][GNU Guix]] (IPA: /ɡiːks/) is a purely functional package manager, and
associated free software distribution, for the [[https://www.gnu.org/gnu/gnu.html][GNU system]].  In addition
to standard package management features, Guix supports transactional
upgrades and roll-backs, unprivileged package management, per-user
profiles, and garbage collection.

It provides [[https://www.gnu.org/software/guile/][Guile]] Scheme APIs, including a high-level embedded
domain-specific languages (EDSLs) to describe how packages are to be
built and composed.

A user-land free software distribution for GNU/Linux comes as part of
Guix.

Guix is based on the [[https://nixos.org/nix/][Nix]] package manager.


* Requirements

GNU Guix currently depends on the following packages:

  - [[https://gnu.org/software/guile/][GNU Guile 2.2.x or 2.0.x]], version 2.0.9 or later
  - [[https://gnupg.org/][GNU libgcrypt]]
  - [[https://www.gnu.org/software/make/][GNU Make]]
  - optionally [[https://savannah.nongnu.org/projects/guile-json/][Guile-JSON]], for the 'guix import pypi' command
  - optionally [[https://www.gnutls.org][GnuTLS]] compiled with guile support enabled, for HTTPS support
    in the 'guix download' command.  Note that 'guix import pypi' requires
    this functionality.

Unless `--disable-daemon' was passed, the following packages are needed:

  - [[https://sqlite.org/][SQLite 3]]
  - [[http://www.bzip.org][libbz2]]
  - [[https://gcc.gnu.org][GCC's g++]]

When `--disable-daemon' was passed, you instead need the following:

  - [[https://nixos.org/nix/][Nix]]

* Installation

See the manual for the installation instructions, either by running

  info -f doc/guix.info "Installation"

or by checking the [[https://www.gnu.org/software/guix/manual/guix.html#Installation][web copy of the manual]].

For information on installation from a Git checkout, please see the section
"Building from Git" in the manual.

* Installing Guix from Guix

You can re-build and re-install Guix using a system that already runs Guix.
To do so:

  - Start a shell with the development environment for Guix:

      guix environment guix

  - Re-run the 'configure' script passing it the option
    '--localstatedir=/somewhere', where '/somewhere' is the 'localstatedir'
    value of the currently installed Guix (failing to do that would lead the
    new Guix to consider the store to be empty!).

  - Run "make", "make check", and "make install".

* How It Works

Guix does the high-level preparation of a /derivation/.  A derivation is
the promise of a build; it is stored as a text file under
=/gnu/store/xxx.drv=.  The (guix derivations) module provides the
`derivation' primitive, as well as higher-level wrappers such as
`build-expression->derivation'.

Guix does remote procedure calls (RPCs) to the Guix or Nix daemon (the
=guix-daemon= or =nix-daemon= command), which in turn performs builds
and accesses to the Nix store on its behalf.  The RPCs are implemented
in the (guix store) module.

* Installing Guix as non-root

The Guix daemon allows software builds to be performed under alternate
user accounts, which are normally created specifically for this
purpose.  For instance, you may have a pool of accounts in the
=guixbuild= group, and then you can instruct =guix-daemon= to use them
like this:

  $ guix-daemon --build-users-group=guixbuild

However, unless it is run as root, =guix-daemon= cannot switch users.
In that case, it falls back to using a setuid-root helper program call
=nix-setuid-helper=.  That program is not setuid-root by default when
you install it; instead you should run a command along these lines
(assuming Guix is installed under /usr/local):

  # chown root.root /usr/local/libexec/nix-setuid-helper
  # chmod 4755 /usr/local/libexec/nix-setuid-helper

* Contact

GNU Guix is hosted at https://savannah.gnu.org/projects/guix/.

Please email <bug-guix@gnu.org> for bug reports or questions regarding
Guix and its distribution; email <gnu-system-discuss@gnu.org> for
general issues regarding the GNU system.

Join #guix on irc.freenode.net.

* Guix & Nix

GNU Guix is based on [[https://nixos.org/nix/][the Nix package manager]].  It implements the same
package deployment paradigm, and in fact it reuses some of its code.
Yet, different engineering decisions were made for Guix, as described
below.

Nix is really two things: a package build tool, implemented by a library
and daemon, and a special-purpose programming language.  GNU Guix relies
on the former, but uses Scheme as a replacement for the latter.

Using Scheme instead of a specific language allows us to get all the
features and tooling that come with Guile (compiler, debugger, REPL,
Unicode, libraries, etc.)  And it means that we have a general-purpose
language, on top of which we can have embedded domain-specific languages
(EDSLs), such as the one used to define packages.  This broadens what
can be done in package recipes themselves, and what can be done around them.

Technically, Guix makes remote procedure calls to the ‘nix-worker’
daemon to perform operations on the store.  At the lowest level, Nix
“derivations” represent promises of a build, stored in ‘.drv’ files in
the store.  Guix produces such derivations, which are then interpreted
by the daemon to perform the build.  Thus, Guix derivations can use
derivations produced by Nix (and vice versa).

With Nix and the [[https://nixos.org/nixpkgs][Nixpkgs]] distribution, package composition happens at
the Nix language level, but builders are usually written in Bash.
Conversely, Guix encourages the use of Scheme for both package
composition and builders.  Likewise, the core functionality of Nix is
written in C++ and Perl; Guix relies on some of the original C++ code,
but exposes all the API as Scheme.

* Related software

  - [[https://nixos.org][Nix, Nixpkgs, and NixOS]], functional package manager and associated
    software distribution, are the inspiration of Guix
  - [[https://www.gnu.org/software/stow/][GNU Stow]] builds around the idea of one directory per prefix, and a
    symlink tree to create user environments
  - [[https://www.pvv.ntnu.no/~arnej/store/storedoc_6.html][STORE]] shares the same idea
  - [[https://live.gnome.org/OSTree/][GNOME's OSTree]] allows bootable system images to be built from a
    specified set of packages
  - The [[https://www.gnu.org/s/gsrc/][GNU Source Release Collection]] (GSRC) is a user-land software
    distribution; unlike Guix, it relies on core tools available on the
    host system
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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2015, 2016 Alex Kost <alezost@gmail.com>
;;; Copyright © 2016 Chris Marusich <cmmarusich@gmail.com>
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;; Copyright © 2019 Meiyo Peng <meiyo.peng@gmail.com>
;;; Copyright © 2019, 2020 Miguel Ángel Arruga Vivas <rosen644835@gmail.com>
;;; Copyright © 2020 Danny Milosavljevic <dannym@scratchpost.org>
;;; Copyright © 2020, 2021 Brice Waegeneire <brice@waegenei.re>
;;; Copyright © 2020 Florian Pelz <pelzflorian@pelzflorian.de>
;;; Copyright © 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com>
;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <jannek@gnu.org>
;;; Copyright © 2020 Efraim Flashner <efraim@flashner.co.il>
;;; Copyright © 2021 Maxime Devos <maximedevos@telenet.be>
;;; Copyright © 2021 raid5atemyhomework <raid5atemyhomework@protonmail.com>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gnu system)
  #:use-module (guix inferior)
  #:use-module (guix store)
  #:use-module (guix monads)
  #:use-module (guix gexp)
  #:use-module (guix records)
  #:use-module (guix packages)
  #:use-module (guix derivations)
  #:use-module (guix profiles)
  #:use-module ((guix utils) #:select (substitute-keyword-arguments))
  #:use-module (guix i18n)
  #:use-module (guix diagnostics)
  #:use-module (gnu packages admin)
  #:use-module (gnu packages base)
  #:use-module (gnu packages bash)
  #:use-module (gnu packages compression)
  #:use-module (gnu packages cross-base)
  #:use-module (gnu packages cryptsetup)
  #:use-module (gnu packages disk)
  #:use-module (gnu packages file-systems)
  #:use-module (gnu packages firmware)
  #:use-module (gnu packages gawk)
  #:use-module (gnu packages guile)
  #:use-module (gnu packages guile-xyz)
  #:use-module (gnu packages hurd)
  #:use-module (gnu packages less)
  #:use-module (gnu packages linux)
  #:use-module (gnu packages man)
  #:use-module (gnu packages nano)
  #:use-module (gnu packages nvi)
  #:use-module (gnu packages package-management)
  #:use-module (gnu packages pciutils)
  #:use-module (gnu packages texinfo)
  #:use-module (gnu packages text-editors)
  #:use-module (gnu packages wget)
  #:use-module (gnu services)
  #:use-module (gnu services shepherd)
  #:use-module (gnu services base)
  #:use-module (gnu bootloader)
  #:use-module (gnu system shadow)
  #:use-module (gnu system nss)
  #:use-module (gnu system locale)
  #:use-module (gnu system pam)
  #:use-module (gnu system linux-initrd)
  #:use-module (gnu system setuid)
  #:use-module (gnu system uuid)
  #:use-module (gnu system file-systems)
  #:use-module (gnu system mapped-devices)
  #:use-module (ice-9 match)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-34)
  #:use-module (srfi srfi-35)
  #:use-module (rnrs bytevectors)
  #:export (operating-system
            operating-system?
            this-operating-system

            operating-system-bootloader
            operating-system-services
            operating-system-essential-services
            operating-system-default-essential-services
            operating-system-user-services
            operating-system-packages
            operating-system-host-name
            operating-system-hosts-file
            operating-system-hurd
            operating-system-kernel
            operating-system-kernel-file
            operating-system-kernel-arguments
            operating-system-label
            operating-system-default-label
            operating-system-initrd-modules
            operating-system-initrd
            operating-system-users
            operating-system-groups
            operating-system-issue
            operating-system-timezone
            operating-system-locale
            operating-system-locale-definitions
            operating-system-locale-libcs
            operating-system-mapped-devices
            operating-system-file-systems
            operating-system-store-file-system
            operating-system-user-mapped-devices
            operating-system-boot-mapped-devices
            operating-system-bootloader-crypto-devices
            operating-system-activation-script
            operating-system-user-accounts
            operating-system-shepherd-service-names
            operating-system-user-kernel-arguments
            operating-system-firmware
            operating-system-keyboard-layout
            operating-system-name-service-switch
            operating-system-pam-services
            operating-system-setuid-programs
            operating-system-skeletons
            operating-system-sudoers-file
            operating-system-swap-devices
            operating-system-kernel-loadable-modules
            operating-system-location

            operating-system-derivation
            operating-system-profile
            operating-system-bootcfg
            operating-system-etc-directory
            operating-system-locale-directory
            operating-system-boot-script
            operating-system-uuid

            system-linux-image-file-name
            operating-system-with-gc-roots
            operating-system-with-provenance

            hurd-default-essential-services

            boot-parameters
            boot-parameters?
            boot-parameters-label
            boot-parameters-root-device
            boot-parameters-bootloader-name
            boot-parameters-bootloader-menu-entries
            boot-parameters-store-crypto-devices
            boot-parameters-store-device
            boot-parameters-store-directory-prefix
            boot-parameters-store-mount-point
            boot-parameters-locale
            boot-parameters-kernel
            boot-parameters-kernel-arguments
            boot-parameters-initrd
            boot-parameters-multiboot-modules
            read-boot-parameters
            read-boot-parameters-file
            boot-parameters->menu-entry

            local-host-aliases
            %root-account
            %setuid-programs
            %sudoers-specification
            %base-packages
            %base-packages-interactive
            %base-packages-linux
            %base-packages-networking
            %base-packages-disk-utilities
            %base-packages-utils
            %base-firmware
            %default-kernel-arguments))

;;; Commentary:
;;;
;;; This module supports whole-system configuration.
;;;
;;; Code:

(define (bootable-kernel-arguments system root-device)
  "Return a list of kernel arguments (gexps) to boot SYSTEM from ROOT-DEVICE."
  (list (string-append "--root="
                       ;; Note: Always use the DCE format because that's what
                       ;; (gnu build linux-boot) expects for the '--root'
                       ;; kernel command-line option.
                       (file-system-device->string root-device
                                                   #:uuid-type 'dce))
        #~(string-append "--system=" #$system)
        #~(string-append "--load=" #$system "/boot")))

;; System-wide configuration.
;; TODO: Add per-field docstrings/stexi.
(define-record-type* <operating-system> operating-system
  make-operating-system
  operating-system?
  this-operating-system

  (kernel operating-system-kernel                 ; package
          (default linux-libre))
  (kernel-loadable-modules operating-system-kernel-loadable-modules
                    (default '()))                ; list of packages
  (kernel-arguments operating-system-user-kernel-arguments
                    (default %default-kernel-arguments)) ; list of gexps/strings
  (hurd operating-system-hurd
        (default #f))                             ; package
  (bootloader operating-system-bootloader)        ; <bootloader-configuration>
  (label operating-system-label                   ; string
         (thunked)
         (default (operating-system-default-label this-operating-system)))

  (keyboard-layout operating-system-keyboard-layout ;#f | <keyboard-layout>
                   (default #f))
  (initrd operating-system-initrd                 ; (list fs) -> file-like
          (default base-initrd))
  (initrd-modules operating-system-initrd-modules ; list of strings
                  (thunked)                       ; it's system-dependent
                  (default %base-initrd-modules))

  (firmware operating-system-firmware             ; list of packages
            (default %base-firmware))

  (host-name operating-system-host-name)          ; string
  (hosts-file operating-system-hosts-file         ; file-like | #f
              (default #f))

  (mapped-devices operating-system-mapped-devices ; list of <mapped-device>
                  (default '()))
  (file-systems operating-system-file-systems)    ; list of fs
  (swap-devices operating-system-swap-devices     ; list of strings
                (default '()))

  (users operating-system-users                   ; list of user accounts
         (default %base-user-accounts))
  (groups operating-system-groups                 ; list of user groups
          (default %base-groups))

  (skeletons operating-system-skeletons           ; list of name/file-like value
             (default (default-skeletons)))
  (issue operating-system-issue                   ; string
         (default %default-issue))

  (packages operating-system-packages             ; list of (PACKAGE OUTPUT...)
            (default %base-packages))             ; or just PACKAGE

  (timezone operating-system-timezone)            ; string
  (locale   operating-system-locale               ; string
            (default "en_US.utf8"))
  (locale-definitions operating-system-locale-definitions ; list of <locale-definition>
                      (default %default-locale-definitions))
  (locale-libcs operating-system-locale-libcs     ; list of <packages>
                (default %default-locale-libcs))
  (name-service-switch operating-system-name-service-switch ; <name-service-switch>
                       (default %default-nss))

  (essential-services operating-system-essential-services ; list of services
                      (thunked)
                      (default (operating-system-default-essential-services
                                this-operating-system)))
  (services operating-system-user-services        ; list of services
            (default %base-services))

  (pam-services operating-system-pam-services     ; list of PAM services
                (default (base-pam-services)))
  (setuid-programs operating-system-setuid-programs
                   (default %setuid-programs)     ; list of <setuid-program>
                   (sanitize ensure-setuid-program-list))

  (sudoers-file operating-system-sudoers-file     ; file-like
                (default %sudoers-specification))

  (location operating-system-location             ; <location>
            (default (and=> (current-source-location)
                            source-properties->location))
            (innate)))

(define (operating-system-kernel-arguments os root-device)
  "Return all the kernel arguments, including the ones not specified
directly by the user."
  (append (bootable-kernel-arguments os root-device)
          (operating-system-user-kernel-arguments os)))


;;;
;;; Boot parameters
;;;

(define-record-type* <boot-parameters>
  boot-parameters make-boot-parameters boot-parameters?
  (label            boot-parameters-label)
  ;; Because we will use the 'store-device' to create the GRUB search command,
  ;; the 'store-device' has slightly different semantics than 'root-device'.
  ;; The 'store-device' can be a file system uuid, a file system label, or #f,
  ;; but it cannot be a device file name such as "/dev/sda3", since GRUB would
  ;; not understand that.  The 'root-device', on the other hand, corresponds
  ;; exactly to the device field of the <file-system> object representing the
  ;; OS's root file system, so it might be a device file name like
  ;; "/dev/sda3".  The 'store-directory-prefix' field contains #f or the store
  ;; file name inside the 'store-device' as it is seen by GRUB, e.g. it would
  ;; contain "/storefs" if the store is located in that subvolume of a btrfs
  ;; partition.
  (root-device      boot-parameters-root-device)
  (bootloader-name  boot-parameters-bootloader-name)
  (bootloader-menu-entries                        ;list of <menu-entry>
   boot-parameters-bootloader-menu-entries)
  (store-device     boot-parameters-store-device)
  (store-mount-point boot-parameters-store-mount-point)
  (store-directory-prefix boot-parameters-store-directory-prefix)
  (store-crypto-devices boot-parameters-store-crypto-devices
                        (default '()))
  (locale           boot-parameters-locale)
  (kernel           boot-parameters-kernel)
  (kernel-arguments boot-parameters-kernel-arguments)
  (initrd           boot-parameters-initrd)
  (multiboot-modules boot-parameters-multiboot-modules))

(define (ensure-not-/dev device)
  "If DEVICE starts with a slash, return #f.  This is meant to filter out
Linux device names such as /dev/sda, and to preserve GRUB device names and
file system labels."
  (if (and (string? device) (string-prefix? "/" device))
      #f
      device))

(define (read-boot-parameters port)
  "Read boot parameters from PORT and return the corresponding
<boot-parameters> object or #f if the format is unrecognized."
  (define device-sexp->device
    (match-lambda
      (('uuid (? symbol? type) (? bytevector? bv))
       (bytevector->uuid bv type))
      (('file-system-label (? string? label))
       (file-system-label label))
      ((? bytevector? bv)                         ;old format
       (bytevector->uuid bv 'dce))
      ((? string? device)
       (if (string-contains device ":/")
           device ; nfs-root
           ;; It used to be that we would not distinguish between labels and
           ;; device names.  Try to infer the right thing here.
           (if (string-prefix? "/" device)
               device
               (file-system-label device))))))
  (define uuid-sexp->uuid
    (match-lambda
      (('uuid (? symbol? type) (? bytevector? bv))
       (bytevector->uuid bv type))
      (x
       (warning (G_ "unrecognized uuid ~a at '~a'~%") x (port-filename port))
       #f)))

  (match (read port)
    (('boot-parameters ('version 0)
                       ('label label) ('root-device root)
                       ('kernel kernel)
                       rest ...)
     (boot-parameters
      (label label)
      (root-device (device-sexp->device root))

      (bootloader-name
       (match (assq 'bootloader-name rest)
         ((_ args) args)
         (#f       'grub))) ; for compatibility reasons.

      (bootloader-menu-entries
       (match (assq 'bootloader-menu-entries rest)
         ((_ entries) (map sexp->menu-entry entries))
         (#f          '())))

      ;; In the past, we would store the directory name of linux instead of
      ;; the absolute file name of its image.  Detect that and correct it.
      (kernel (if (string=? kernel (direct-store-path kernel))
                  (string-append kernel "/"
                                 (system-linux-image-file-name))
                  kernel))

      (kernel-arguments
       (match (assq 'kernel-arguments rest)
         ((_ args) args)
         (#f       '())))                         ;the old format

      (initrd
       (match (assq 'initrd rest)
         (('initrd ('string-append directory file)) ;the old format
          (string-append directory file))
         (('initrd (? string? file))
          file)
         (#f #f)))

      (multiboot-modules
       (match (assq 'multiboot-modules rest)
         ((_ args) args)
         (#f       '())))

      (locale
       (match (assq 'locale rest)
         ((_ locale) locale)
         (#f         #f)))

      (store-device
       ;; Linux device names like "/dev/sda1" are not suitable GRUB device
       ;; identifiers, so we just filter them out.
       (ensure-not-/dev
        (match (assq 'store rest)
          (('store ('device #f) _ ...)
           root-device)
          (('store ('device device) _ ...)
           (device-sexp->device device))
          (_                                      ;the old format
           root-device))))

      (store-directory-prefix
       (match (assq 'store rest)
         (('store . store-data)
          (match (assq 'directory-prefix store-data)
            (('directory-prefix prefix) prefix)
            ;; No directory-prefix found.
            (_ #f)))
         (_
          ;; No store found, old format.
          #f)))

      (store-crypto-devices
       (match (assq 'store rest)
         (('store . store-data)
          (match (assq 'crypto-devices store-data)
            (('crypto-devices (devices ...))
             (map uuid-sexp->uuid devices))
            (('crypto-devices dev)
             (warning (G_ "unrecognized crypto-devices ~S at '~a'~%")
                      dev (port-filename port))
             '())
            (_
             ;; No crypto-devices found.
             '())))
         (_
          ;; No store found, old format.
          '())))

      (store-mount-point
       (match (assq 'store rest)
         (('store ('device _) ('mount-point mount-point) _ ...)
          mount-point)
         (_                                       ;the old format
          "/")))))
    (x                                            ;unsupported format
     (warning (G_ "unrecognized boot parameters at '~a'~%")
              (port-filename port))
     #f)))

(define (read-boot-parameters-file system)
  "Read boot parameters from SYSTEM's (system or generation) \"parameters\"
file and returns the corresponding <boot-parameters> object or #f if the
format is unrecognized.
The object has its kernel-arguments extended in order to make it bootable."
  (let* ((file (string-append system "/parameters"))
         (params (call-with-input-file file read-boot-parameters))
         (root (boot-parameters-root-device params)))
    (boot-parameters
     (inherit params)
     (kernel-arguments (append (bootable-kernel-arguments system root)
                               (boot-parameters-kernel-arguments params))))))

(define (boot-parameters->menu-entry conf)
  (let* ((kernel (boot-parameters-kernel conf))
         (multiboot-modules (boot-parameters-multiboot-modules conf))
         (multiboot? (pair? multiboot-modules)))
    (menu-entry
     (label (boot-parameters-label conf))
     (device (boot-parameters-store-device conf))
     (device-mount-point (boot-parameters-store-mount-point conf))
     (linux (and (not multiboot?) kernel))
     (linux-arguments (if (not multiboot?)
                          (boot-parameters-kernel-arguments conf)
                          '()))
     (initrd (boot-parameters-initrd conf))
     (multiboot-kernel (and multiboot? kernel))
     (multiboot-arguments (if multiboot?
                              (boot-parameters-kernel-arguments conf)
                              '()))
     (multiboot-modules (if multiboot?
                            (boot-parameters-multiboot-modules conf)
                            '())))))


;;;
;;; Services.
;;;

(define (non-boot-file-system-service os)
  "Return the file system service for the file systems of OS that are not
marked as 'needed-for-boot'."
  (define file-systems
    (remove file-system-needed-for-boot?
            (operating-system-file-systems os)))

  (define mapped-devices-for-boot
    (operating-system-boot-mapped-devices os))

  (define (device-mappings fs)
    (let ((device (file-system-device fs)))
      (if (string? device)                        ;title is 'device
          (filter (lambda (md)
                    (any (cut string=? device <>)
                         (map (cut string-append "/dev/mapper" <>)
                              (mapped-device-targets md))))
                  (operating-system-mapped-devices os))
          '())))

  (define (add-dependencies fs)
    ;; Add the dependencies due to device mappings to FS.
    (file-system
      (inherit fs)
      (dependencies
       (delete-duplicates
        (remove (cut member <> mapped-devices-for-boot)
                (append (device-mappings fs)
                        (file-system-dependencies fs)))
        eq?))))

  (service file-system-service-type
           (map add-dependencies file-systems)))

(define (mapped-device-users device file-systems)
  "Return the subset of FILE-SYSTEMS that use DEVICE."
  (let ((targets (map (cut string-append "/dev/mapper/" <>)
                      (mapped-device-targets device))))
    (filter (lambda (fs)
              (or (member device (file-system-dependencies fs))
                  (and (string? (file-system-device fs))
                       (any (cut string=? (file-system-device fs) <>) targets))))
            file-systems)))

(define (operating-system-user-mapped-devices os)
  "Return the subset of mapped devices that can be installed in
user-land--i.e., those not needed during boot."
  (let ((devices      (operating-system-mapped-devices os))
        (file-systems (operating-system-file-systems os)))
   (filter (lambda (md)
             (let ((users (mapped-device-users md file-systems)))
               (not (any file-system-needed-for-boot? users))))
           devices)))

(define (operating-system-boot-mapped-devices os)
  "Return the subset of mapped devices that must be installed during boot,
from the initrd."
  (let ((devices      (operating-system-mapped-devices os))
        (file-systems (operating-system-file-systems os)))
   (filter (lambda (md)
             (let ((users (mapped-device-users md file-systems)))
               (any file-system-needed-for-boot? users)))
           devices)))

(define (operating-system-bootloader-crypto-devices os)
  "Return the subset of mapped devices that the bootloader must open.
Only devices specified by uuid are supported."
  (define (valid-crypto-device? dev)
    (or (uuid? dev)
        (begin
          (warning (G_ "\
mapped-device '~a' may not be mounted by the bootloader.~%")
                   dev)
          #f)))
  (filter-map (match-lambda
                ((and (= mapped-device-type type)
                      (= mapped-device-source source))
                 (and (eq? luks-device-mapping type)
                      (valid-crypto-device? source)
                      source))
                (_ #f))
              ;; XXX: Ordering is important, we trust the returned one.
              (operating-system-boot-mapped-devices os)))

(define (device-mapping-services os)
  "Return the list of device-mapping services for OS as a list."
  (map device-mapping-service
       (operating-system-user-mapped-devices os)))

(define (swap-services os)
  "Return the list of swap services for OS."
  (map swap-service (operating-system-swap-devices os)))

(define* (system-linux-image-file-name #:optional
                                       (target (or (%current-target-system)
                                                   (%current-system))))
  "Return the basename of the kernel image file for TARGET."
  (cond
   ((string-prefix? "arm" target) "zImage")
   ((string-prefix? "mips" target) "vmlinuz")
   ((string-prefix? "aarch64" target) "Image")
   (else "bzImage")))

(define (operating-system-kernel-file os)
  "Return an object representing the absolute file name of the kernel image of
OS."
  (if (operating-system-hurd os)
      (file-append (operating-system-kernel os) "/boot/gnumach")
      (file-append (operating-system-kernel os)
                      "/" (system-linux-image-file-name))))

(define %default-modprobe-blacklist
  ;; List of kernel modules to blacklist by default.
  '("usbmouse" ;races with bcm5974, see <https://bugs.gnu.org/35574>
    "usbkbd")) ;races with usbhid, see <https://issues.guix.gnu.org/35574#18>

(define %default-kernel-arguments
  ;; Default arguments passed to the kernel.
  (list (string-append "modprobe.blacklist="
                       (string-join %default-modprobe-blacklist ","))
        "quiet"))

(define* (operating-system-directory-base-entries os)
  "Return the basic entries of the 'system' directory of OS for use as the
value of the SYSTEM-SERVICE-TYPE service."
  (let* ((locale  (operating-system-locale-directory os))
         (kernel  (operating-system-kernel os))
         (hurd    (operating-system-hurd os))
         (initrd  (and (not hurd) (operating-system-initrd-file os)))
         (params  (operating-system-boot-parameters-file os)))
    `(,@(if hurd
          `(("hurd" ,hurd)
            ("kernel" ,kernel))
          '())
      ("parameters" ,params)
      ,@(if initrd `(("initrd" ,initrd)) '())
      ("locale" ,locale))))   ;used by libc

(define (operating-system-default-essential-services os)
  "Return the list of essential services for OS.  These are special services
that implement part of what's declared in OS are responsible for low-level
bookkeeping."
  (define known-fs
    (map file-system-mount-point (operating-system-file-systems os)))

  (let* ((mappings  (device-mapping-services os))
         (root-fs   (root-file-system-service))
         (other-fs  (non-boot-file-system-service os))
         (swaps     (swap-services os))
         (procs     (service user-processes-service-type))
         (host-name (host-name-service (operating-system-host-name os)))
         (entries   (operating-system-directory-base-entries os)))
    (cons* (service system-service-type entries)
           (service linux-builder-service-type
                    (linux-builder-configuration
                      (kernel   (operating-system-kernel os))
                      (modules  (operating-system-kernel-loadable-modules os))))
           %boot-service

           ;; %SHEPHERD-ROOT-SERVICE must come last so that the gexp that
           ;; execs shepherd comes last in the boot script (XXX).  Likewise,
           ;; the cleanup service must come first so that its gexp runs before
           ;; activation code.
           (service cleanup-service-type #f)
           %activation-service
           %shepherd-root-service

           (pam-root-service (operating-system-pam-services os))
           (account-service (append (operating-system-accounts os)
                                    (operating-system-groups os))
                            (operating-system-skeletons os))
           (operating-system-etc-service os)
           (service fstab-service-type
                    (filter file-system-needed-for-boot?
                            (operating-system-file-systems os)))
           (session-environment-service
            (operating-system-environment-variables os))
           host-name procs root-fs
           (service setuid-program-service-type
                    (operating-system-setuid-programs os))
           (service profile-service-type
                    (operating-system-packages os))
           other-fs
           (append mappings swaps

                   ;; Add the firmware service.
                   (list %linux-bare-metal-service
                         (service firmware-service-type
                                  (operating-system-firmware os)))))))

(define (hurd-default-essential-services os)
  (let ((entries (operating-system-directory-base-entries os)))
    (list (service system-service-type entries)
          %boot-service
          %hurd-startup-service
          %activation-service
          %shepherd-root-service
          (service user-processes-service-type)
          (account-service (append (operating-system-accounts os)
                                   (operating-system-groups os))
                           (operating-system-skeletons os))
          (root-file-system-service)
          (service file-system-service-type '())
          (service fstab-service-type
                   (filter file-system-needed-for-boot?
                           (operating-system-file-systems os)))
          (pam-root-service (operating-system-pam-services os))
          (operating-system-etc-service os)
          (service setuid-program-service-type
                   (operating-system-setuid-programs os))
          (service profile-service-type (operating-system-packages os)))))

(define* (operating-system-services os)
  "Return all the services of OS, including \"essential\" services."
  (instantiate-missing-services
   (append (operating-system-user-services os)
           (operating-system-essential-services os))))

(define (operating-system-with-gc-roots os roots)
  "Return a variant of OS where ROOTS are registered as GC roots."
  (operating-system
    (inherit os)

    ;; We use this procedure for the installation OS, which already defines GC
    ;; roots.  Add ROOTS to those.
    (services (cons (simple-service 'extra-root
                                    gc-root-service-type roots)
                    (operating-system-user-services os)))))

(define (operating-system-configuration-file os)
  "Return the configuration file of OS, based on its 'location' field, or #f
if it could not be determined."
  (let ((file (and=> (operating-system-location os)
                     location-file)))
    (and file
         (or (and (string-prefix? "/" file) file)
             (search-path %load-path file)))))

(define* (operating-system-with-provenance os
                                           #:optional
                                           (config-file
                                            (operating-system-configuration-file
                                             os)))
  "Return a variant of OS that stores its own provenance information,
including CONFIG-FILE, if available.  This is achieved by adding an instance
of PROVENANCE-SERVICE-TYPE to its services."
  (operating-system
    (inherit os)
    (services (cons (service provenance-service-type config-file)
                    (operating-system-user-services os)))))


;;;
;;; /etc.
;;;

(define %base-firmware
  ;; Firmware usable by default.
  (list ath9k-htc-firmware
        openfwwf-firmware))

(define %base-packages-utils
  ;; Default set of  utilities packages.
 (cons* procps psmisc which
        (@ (gnu packages admin) shadow) ;for 'passwd'

        guile-3.0-latest

        ;; The packages below are also in %FINAL-INPUTS, so take them from
        ;; there to avoid duplication.
        (list bash coreutils findutils grep sed
              diffutils patch gawk tar gzip bzip2 xz lzip)))

(define %base-packages-linux
  ;; Default set of linux specific packages.
  (list pciutils usbutils
        util-linux+udev
        ;; Get 'insmod' & co. from kmod, not module-init-tools, since udev
        ;; already depends on it anyway.
        kmod eudev))

(define %base-packages-interactive
  ;; Default set of common interactive packages.
  (list less mg nano
        nvi
        man-db
        info-reader                     ;the standalone Info reader (no Perl)
        bash-completion
        kbd
        ;; The 'sudo' command is already in %SETUID-PROGRAMS, but we also
        ;; want the other commands and the man pages (notably because
        ;; auto-completion in Emacs shell relies on man pages.)
        sudo
        guile-readline guile-colorized))

(define %base-packages-networking
  ;; Default set of networking packages.
  (list inetutils isc-dhcp
        iproute
        wget
        ;; wireless-tools is deprecated in favor of iw, but it's still what
        ;; many people are familiar with, so keep it around.
        iw wireless-tools))

(define %base-packages-disk-utilities
  ;; A well-rounded set of packages for interacting with disks, partitions
  ;; and filesystems.
  (list parted gptfdisk ddrescue
        ;; We used to provide fdisk from GNU fdisk, but as of version 2.0.0a
        ;; it pulls Guile 1.8, which takes unreasonable space; furthermore
        ;; util-linux's fdisk is already available, in %base-packages-linux.
        cryptsetup mdadm
        dosfstools
        btrfs-progs
        f2fs-tools
        jfsutils
        xfsprogs))

(define %base-packages
  ;; Default set of packages globally visible.  It should include anything
  ;; required for basic administrator tasks.
  (append (list e2fsprogs)
          %base-packages-interactive
          %base-packages-linux
          %base-packages-networking
          %base-packages-utils))

(define %default-issue
  ;; Default contents for /etc/issue.
  "
This is the GNU system.  Welcome.\n")

(define (local-host-aliases host-name)
  "Return aliases for HOST-NAME, to be used in /etc/hosts."
  (string-append "127.0.0.1 localhost " host-name "\n"
                 "::1       localhost " host-name "\n"))

(define (default-/etc/hosts host-name)
  "Return the default /etc/hosts file."
  (plain-file "hosts" (local-host-aliases host-name)))

(define (validated-sudoers-file file)
  "Return a copy of FILE, a sudoers file, after checking that it is
syntactically correct."
  (computed-file "sudoers"
                 (with-imported-modules '((guix build utils))
                   #~(begin
                       (use-modules (guix build utils))

                       (invoke #+(file-append sudo "/sbin/visudo")
                               "--check" "--file" #$file)
                       (copy-file #$file #$output)))))

(define* (operating-system-etc-service os)
  "Return a <service> that builds a directory containing the static part of
the /etc directory."
  (let* ((login.defs
          (plain-file "login.defs"
                      (string-append
                        "# Default paths for non-login shells started by su(1).\n"
                        "ENV_PATH    /run/setuid-programs:"
                        "/run/current-system/profile/bin:"
                        "/run/current-system/profile/sbin\n"
                        "ENV_SUPATH  /run/setuid-programs:"
                        "/run/current-system/profile/bin:"
                        "/run/current-system/profile/sbin\n")))

         (hurd       (operating-system-hurd os))
         (issue      (plain-file "issue" (operating-system-issue os)))
         (nsswitch   (operating-system-name-service-switch os))
         (nsswitch   (and nsswitch
                          (plain-file "nsswitch.conf"
                                      (name-service-switch->string nsswitch))))
         (sudoers    (operating-system-sudoers-file os))

        ;; Startup file for POSIX-compliant login shells, which set system-wide
        ;; environment variables.
        (profile    (mixed-text-file "profile"  "\
# Crucial variables that could be missing in the profiles' 'etc/profile'
# because they would require combining both profiles.
# FIXME: See <http://bugs.gnu.org/20255>.
export MANPATH=$HOME/.guix-profile/share/man:/run/current-system/profile/share/man
export INFOPATH=$HOME/.guix-profile/share/info:/run/current-system/profile/share/info
export XDG_DATA_DIRS=$HOME/.guix-profile/share:/run/current-system/profile/share
export XDG_CONFIG_DIRS=$HOME/.guix-profile/etc/xdg:/run/current-system/profile/etc/xdg

# Make sure libXcursor finds cursors installed into user or system profiles.  See <http://bugs.gnu.org/24445>
export XCURSOR_PATH=$HOME/.icons:$HOME/.guix-profile/share/icons:/run/current-system/profile/share/icons

# Ignore the default value of 'PATH'.
unset PATH

# Load the system profile's settings.
GUIX_PROFILE=/run/current-system/profile ; \\
. /run/current-system/profile/etc/profile

# Since 'lshd' does not use pam_env, /etc/environment must be explicitly
# loaded when someone logs in via SSH.  See <http://bugs.gnu.org/22175>.
# We need 'PATH' to be defined here, for 'cat' and 'cut'.  Do this before
# reading the user's 'etc/profile' to allow variables to be overridden.
if [ -f /etc/environment -a -n \"$SSH_CLIENT\" \\
     -a -z \"$LINUX_MODULE_DIRECTORY\" ]
then
  . /etc/environment
  export `cat /etc/environment | cut -d= -f1`
fi

# Arrange so that ~/.config/guix/current comes first.
for profile in \"$HOME/.guix-profile\" \"$HOME/.config/guix/current\"
do
  if [ -f \"$profile/etc/profile\" ]
  then
    # Load the user profile's settings.
    GUIX_PROFILE=\"$profile\" ; \\
    . \"$profile/etc/profile\"
  else
    # At least define this one so that basic things just work
    # when the user installs their first package.
    export PATH=\"$profile/bin:$PATH\"
  fi
done

# Prepend setuid programs.
export PATH=/run/setuid-programs:$PATH

# Arrange so that ~/.config/guix/current/share/info comes first.
export INFOPATH=\"$HOME/.config/guix/current/share/info:$INFOPATH\"

# Set the umask, notably for users logging in via 'lsh'.
# See <http://bugs.gnu.org/22650>.
umask 022

# Allow Hunspell-based applications (IceCat, LibreOffice, etc.) to
# find dictionaries.
export DICPATH=\"$HOME/.guix-profile/share/hunspell:/run/current-system/profile/share/hunspell\"

# Allow GStreamer-based applications to find plugins.
export GST_PLUGIN_PATH=\"$HOME/.guix-profile/lib/gstreamer-1.0\"

if [ -n \"$BASH_VERSION\" -a -f /etc/bashrc ]
then
  # Load Bash-specific initialization code.
  . /etc/bashrc
fi
"))

        (bashrc    (plain-file "bashrc" "\
# Bash-specific initialization.

# The 'bash-completion' package.
if [ -f /run/current-system/profile/etc/profile.d/bash_completion.sh ]
then
  # Bash-completion sources ~/.bash_completion.  It installs a dynamic
  # completion loader that searches its own completion files as well
  # as those in ~/.guix-profile and /run/current-system/profile.
  source /run/current-system/profile/etc/profile.d/bash_completion.sh
fi\n")))
    (etc-service
     `(("services" ,(file-append net-base "/etc/services"))
       ("protocols" ,(file-append net-base "/etc/protocols"))
       ("rpc" ,(file-append net-base "/etc/rpc"))
       ("login.defs" ,#~#$login.defs)
       ("issue" ,#~#$issue)
       ,@(if nsswitch `(("nsswitch.conf" ,#~#$nsswitch)) '())
       ("profile" ,#~#$profile)
       ("bashrc" ,#~#$bashrc)
       ("hosts" ,#~#$(or (operating-system-hosts-file os)
                         (default-/etc/hosts (operating-system-host-name os))))
       ;; Write the operating-system-host-name to /etc/hostname to prevent
       ;; NetworkManager from changing the system's hostname when connecting
       ;; to certain networks.  Some discussion at
       ;; https://lists.gnu.org/archive/html/help-guix/2017-09/msg00037.html
       ("hostname" ,(plain-file "hostname" (operating-system-host-name os)))
       ;; Some programs (e.g., GLib) look at /etc/timezone to find the
       ;; name of the current timezone.  For details, see
       ;; https://lists.gnu.org/archive/html/guix-devel/2019-07/msg00166.html
       ;; Some programs expect a terminating newline.
       ("timezone" ,(plain-file "timezone"
                                (string-append
                                 (string-trim-both
                                  (operating-system-timezone os))
                                 "\n")))
       ("localtime" ,(file-append tzdata "/share/zoneinfo/"
                                  (operating-system-timezone os)))
       ,@(if sudoers
             `(("sudoers" ,(validated-sudoers-file sudoers)))
             '())
       ,@(if hurd
             `(("login" ,(file-append hurd "/etc/login"))
               ("motd"  ,(file-append hurd "/etc/motd"))
               ("ttys"  ,(file-append hurd "/etc/ttys")))
             '())))))

(define %root-account
  ;; Default root account.
  (user-account
   (name "root")
   (password "")
   (uid 0) (group "root")
   (comment "System administrator")
   (home-directory "/root")))

(define (operating-system-accounts os)
  "Return the user accounts for OS, including an obligatory 'root' account,
and excluding accounts requested by services."
  ;; Make sure there's a root account.
  (if (find (lambda (user)
              (and=> (user-account-uid user) zero?))
            (operating-system-users os))
      (operating-system-users os)
      (cons %root-account (operating-system-users os))))

(define (maybe-string->file file-name thing)
  "If THING is a string, return a <plain-file> with THING as its content.
Otherwise just return THING.

This is for backward-compatibility of fields that used to be strings and are
now file-like objects.."
  (match thing
    ((? string?)
     (warning (G_ "using a string for file '~a' is deprecated; \
use 'plain-file' instead~%")
              file-name)
     (plain-file file-name thing))
    (x
     x)))

(define (maybe-file->monadic file-name thing)
  "If THING is a value in %STORE-MONAD, return it as is; otherwise return
THING in the %STORE-MONAD.

This is for backward-compatibility of fields that used to be monadic values
and are now file-like objects."
  (with-monad %store-monad
    (match thing
      ((? procedure?)
       (warning (G_ "using a monadic value for '~a' is deprecated; \
use 'plain-file' instead~%")
                file-name)
       thing)
      (x
       (return x)))))

(define (operating-system-etc-directory os)
  "Return that static part of the /etc directory of OS."
  (etc-directory
   (fold-services (operating-system-services os)
                  #:target-type etc-service-type)))

(define (operating-system-environment-variables os)
  "Return the environment variables of OS for
@var{session-environment-service-type}, to be used in @file{/etc/environment}."
  `(("LANG" . ,(operating-system-locale os))
    ;; Note: No need to set 'TZ' since (1) we provide /etc/localtime, and (2)
    ;; it doesn't work for setuid binaries.  See <https://bugs.gnu.org/29212>.
    ("TZDIR" . ,(file-append tzdata "/share/zoneinfo"))
    ;; Tell 'modprobe' & co. where to look for modules.
    ("LINUX_MODULE_DIRECTORY" . "/run/booted-system/kernel/lib/modules")
    ;; These variables are honored by OpenSSL (libssl) and Git.
    ("SSL_CERT_DIR" . "/etc/ssl/certs")
    ("SSL_CERT_FILE" . "/etc/ssl/certs/ca-certificates.crt")
    ("GIT_SSL_CAINFO" . "/etc/ssl/certs/ca-certificates.crt")

    ;; 'GTK_DATA_PREFIX' must name one directory where GTK+ themes are
    ;; searched for.
    ("GTK_DATA_PREFIX" . "/run/current-system/profile")

    ;; By default, applications that use D-Bus, such as Emacs, abort at startup
    ;; when /etc/machine-id is missing.  Make sure these warnings are non-fatal.
    ("DBUS_FATAL_WARNINGS" . "0")

    ;; XXX: Normally we wouldn't need to do this, but our glibc@2.23 package
    ;; used to look things up in 'PREFIX/lib/locale' instead of
    ;; '/run/current-system/locale' as was intended.  Keep this hack around so
    ;; that people who still have glibc@2.23-using packages in their profiles
    ;; can use them correctly.
    ;; TODO: Remove when glibc@2.23 is long gone.
    ("GUIX_LOCPATH" . "/run/current-system/locale")))

(define-syntax-rule (ensure-setuid-program-list lst)
  "Ensure LST is a list of <setuid-program> records and warn otherwise."
  (%ensure-setuid-program-list lst (current-source-location)))

(define (%ensure-setuid-program-list lst location)
  (define warned? #f)

  (define (warn-once)
    (unless warned?
      (warning (source-properties->location location)
               (G_ "representing setuid programs with file-like objects is \
deprecated; use 'setuid-program' instead~%"))
      (set! warned? #t)))

  (map (match-lambda
         ((? setuid-program? program)
          program)
         (program
          ;; PROGRAM is a file-like or a gexp like #~(string-append #$foo
          ;; "/bin/bar").
          (warn-once)
          (setuid-program (program program))))
       lst))

(define %setuid-programs
  ;; Default set of setuid-root programs.
  (let ((shadow (@ (gnu packages admin) shadow)))
    (map file-like->setuid-program
         (list (file-append shadow "/bin/passwd")
               (file-append shadow "/bin/sg")
               (file-append shadow "/bin/su")
               (file-append shadow "/bin/newgrp")
               (file-append shadow "/bin/newuidmap")
               (file-append shadow "/bin/newgidmap")
               (file-append inetutils "/bin/ping")
               (file-append inetutils "/bin/ping6")
               (file-append sudo "/bin/sudo")
               (file-append sudo "/bin/sudoedit")
               (file-append fuse "/bin/fusermount")

               ;; To allow mounts with the "user" option, "mount" and "umount" must
               ;; be setuid-root.
               (file-append util-linux "/bin/mount")
               (file-append util-linux "/bin/umount")))))

(define %sudoers-specification
  ;; Default /etc/sudoers contents: 'root' and all members of the 'wheel'
  ;; group can do anything.  See
  ;; <http://www.sudo.ws/sudo/man/1.8.10/sudoers.man.html>.
  ;; TODO: Add a declarative API.
  (plain-file "sudoers" "\
root ALL=(ALL) ALL
%wheel ALL=(ALL) ALL\n"))

(define* (operating-system-activation-script os)
  "Return the activation script for OS---i.e., the code that \"activates\" the
stateful part of OS, including user accounts and groups, special directories,
etc."
  (let* ((services   (operating-system-services os))
         (activation (fold-services services
                                    #:target-type activation-service-type)))
    (activation-service->script activation)))

(define* (operating-system-boot-script os)
  "Return the boot script for OS---i.e., the code started by the initrd once
we're running in the final root."
  (let* ((services (operating-system-services os))
         (boot     (fold-services services #:target-type boot-service-type)))
    (service-value boot)))

(define (operating-system-user-accounts os)
  "Return the list of user accounts of OS."
  (let* ((services (operating-system-services os))
         (account  (fold-services services
                                  #:target-type account-service-type)))
    (filter user-account?
            (service-value account))))

(define (operating-system-shepherd-service-names os)
  "Return the list of Shepherd service names for OS."
  (append-map shepherd-service-provision
              (shepherd-configuration-services
               (service-value
                (fold-services (operating-system-services os)
                               #:target-type
                               shepherd-root-service-type)))))

(define* (operating-system-derivation os)
  "Return a derivation that builds OS."
  (let* ((services (operating-system-services os))
         (system   (fold-services services)))
    ;; SYSTEM contains the derivation as a monadic value.
    (service-value system)))

(define* (operating-system-profile os)
  "Return a derivation that builds the system profile of OS."
  (mlet* %store-monad
      ((services -> (operating-system-services os))
       (profile (fold-services services
                               #:target-type profile-service-type)))
    (match profile
      (("profile" profile)
       (return profile)))))

(define (operating-system-root-file-system os)
  "Return the root file system of OS."
  (or (find (lambda (fs)
              (string=? "/" (file-system-mount-point fs)))
            (operating-system-file-systems os))
      (raise (condition
              (&message (message "missing root file system"))
              (&error-location
               (location (operating-system-location os)))))))

(define (operating-system-initrd-file os)
  "Return a gexp denoting the initrd file of OS."
  (define boot-file-systems
    (filter file-system-needed-for-boot?
            (operating-system-file-systems os)))

  (define mapped-devices
    (operating-system-boot-mapped-devices os))

  (define make-initrd
    (operating-system-initrd os))

  (make-initrd boot-file-systems
               #:linux (operating-system-kernel os)
               #:linux-modules
               (operating-system-initrd-modules os)
               #:mapped-devices mapped-devices
               #:keyboard-layout (operating-system-keyboard-layout os)))

(define* (operating-system-uuid os #:optional (type 'dce))
  "Compute UUID object with a deterministic \"UUID\" for OS, of the given
TYPE (one of 'iso9660 or 'dce).  Return a UUID object."
  ;; Note: For this to be deterministic, we must not hash things that contains
  ;; (directly or indirectly) procedures, for example.  That rules out
  ;; anything that contains gexps, thunk or delayed record fields, etc.

  (define service-name
    (compose service-type-name service-kind))

  (define (file-system-digest fs)
    ;; Return a hashable digest that does not contain 'dependencies' since
    ;; this field can contain procedures.
    (let ((device (file-system-device fs)))
      (list (file-system-mount-point fs)
            (file-system-type fs)
            (file-system-device->string device)
            (file-system-options fs))))

  (if (eq? type 'iso9660)
      (let ((pad (compose (cut string-pad <> 2 #\0)
                          number->string))
            (h   (hash (map service-name (operating-system-services os))
                       3600)))
        (bytevector->uuid
         (string->iso9660-uuid
          (string-append "1970-01-01-"
                         (pad (hash (operating-system-host-name os) 24)) "-"
                         (pad (quotient h 60)) "-"
                         (pad (modulo h 60)) "-"
                         (pad (hash (map file-system-digest
                                         (operating-system-file-systems os))
                                    100))))
         'iso9660))
      (bytevector->uuid
       (uint-list->bytevector
        (list (hash (map file-system-digest
                         (operating-system-file-systems os))
                    (- (expt 2 32) 1))
              (hash (operating-system-host-name os)
                    (- (expt 2 32) 1))
              (hash (map service-name (operating-system-services os))
                    (- (expt 2 32) 1))
              (hash (map file-system-digest (operating-system-file-systems os))
                    (- (expt 2 32) 1)))
        (endianness little)
        4)
       type)))

(define (locale-name->definition* name)
  "Variant of 'locale-name->definition' that raises an error upon failure."
  (match (locale-name->definition name)
    (#f
     (raise (formatted-message (G_ "~a: invalid locale name") name)))
    (def def)))

(define (operating-system-locale-directory os)
  "Return the directory containing the locales compiled for the definitions
listed in OS.  The C library expects to find it under
/run/current-system/locale."
  (define name
    (operating-system-locale os))

  (define definitions
    ;; While we're at it, check whether NAME is defined and add it if needed.
    (if (member name (map locale-definition-name
                          (operating-system-locale-definitions os)))
        (operating-system-locale-definitions os)
        (cons (locale-name->definition* name)
              (operating-system-locale-definitions os))))

  (locale-directory definitions
                    #:libcs (operating-system-locale-libcs os)))

(define* (kernel->boot-label kernel #:key hurd)
  "Return a label for the bootloader menu entry that boots KERNEL."
  (cond ((package? hurd)
         (string-append "GNU with the "
                        (string-titlecase (package-name hurd)) " "
                        (package-version hurd)))
        ((package? kernel)
         (string-append "GNU with "
                        (string-titlecase (package-name kernel)) " "
                        (package-version kernel)))
        ((inferior-package? kernel)
         (string-append "GNU with "
                        (string-titlecase (inferior-package-name kernel)) " "
                        (inferior-package-version kernel)))
        (else "GNU")))

(define (operating-system-default-label os)
  "Return the default label for OS, as it will appear in the bootloader menu
entry."
  (kernel->boot-label (operating-system-kernel os)
                      #:hurd (operating-system-hurd os)))

(define (store-file-system file-systems)
  "Return the file system object among FILE-SYSTEMS that contains the store."
  (match (filter (lambda (fs)
                   (and (file-system-mount? fs)
                        (not (memq 'bind-mount (file-system-flags fs)))
                        (string-prefix? (file-system-mount-point fs)
                                        (%store-prefix))))
                 file-systems)
    ((and candidates (head . tail))
     (reduce (lambda (fs1 fs2)
               (if (> (string-length (file-system-mount-point fs1))
                      (string-length (file-system-mount-point fs2)))
                   fs1
                   fs2))
             head
             candidates))))

(define (operating-system-store-file-system os)
  "Return the file system that contains the store of OS."
  (store-file-system (operating-system-file-systems os)))

(define* (operating-system-bootcfg os #:optional (old-entries '()))
  "Return the bootloader configuration file for OS.  Use OLD-ENTRIES,
a list of <menu-entry>, to populate the \"old entries\" menu."
  (let* ((file-systems    (operating-system-file-systems os))
         (root-fs         (operating-system-root-file-system os))
         (root-device     (file-system-device root-fs))
         (locale          (operating-system-locale os))
         (crypto-devices  (operating-system-bootloader-crypto-devices os))
         (params          (operating-system-boot-parameters
                           os root-device
                           #:system-kernel-arguments? #t))
         (entry           (boot-parameters->menu-entry params))
         (bootloader-conf (operating-system-bootloader os)))

    (define generate-config-file
      (bootloader-configuration-file-generator
       (bootloader-configuration-bootloader bootloader-conf)))

    (generate-config-file bootloader-conf (list entry)
                          #:old-entries old-entries
                          #:locale locale
                          #:store-crypto-devices crypto-devices
                          #:store-directory-prefix
			  (btrfs-store-subvolume-file-name file-systems))))

(define (operating-system-multiboot-modules os)
  (if (operating-system-hurd os) (hurd-multiboot-modules os) '()))

(define (hurd-multiboot-modules os)
  (let* ((hurd (operating-system-hurd os))
         (root-file-system-command
          (list (file-append hurd "/hurd/ext2fs.static")
                "ext2fs"
                "--multiboot-command-line='${kernel-command-line}'"
                "--host-priv-port='${host-port}'"
                "--device-master-port='${device-port}'"
                "--exec-server-task='${exec-task}'"
                "--store-type=typed"
                "--x-xattr-translator-records"
                "'${root}'" "'$(task-create)'" "'$(task-resume)'"))
         (target (%current-target-system))
         (libc (if target
                   (with-parameters ((%current-target-system #f))
                     ;; TODO: cross-libc has extra patches for the Hurd;
                     ;; remove in next rebuild cycle
                     (cross-libc target))
                   glibc))
         (exec-server-command
          (list (file-append libc "/lib/ld.so.1") "exec"
                (file-append hurd "/hurd/exec") "'$(exec-task=task-create)'")))
    (list root-file-system-command exec-server-command)))

(define* (operating-system-boot-parameters os root-device
                                           #:key system-kernel-arguments?)
  "Return a monadic <boot-parameters> record that describes the boot
parameters of OS.  When SYSTEM-KERNEL-ARGUMENTS? is true, add kernel arguments
such as '--root' and '--load' to <boot-parameters>."
  (let* ((initrd          (and (not (operating-system-hurd os))
                               (operating-system-initrd-file os)))
         (store           (operating-system-store-file-system os))
         (file-systems    (operating-system-file-systems os))
         (crypto-devices  (operating-system-bootloader-crypto-devices os))
         (locale          (operating-system-locale os))
         (bootloader      (bootloader-configuration-bootloader
                           (operating-system-bootloader os)))
         (bootloader-name (bootloader-name bootloader))
         (label           (operating-system-label os))
         (multiboot-modules (operating-system-multiboot-modules os)))
    (boot-parameters
     (label label)
     (root-device root-device)
     (kernel (operating-system-kernel-file os))
     (kernel-arguments
      (if system-kernel-arguments?
          (operating-system-kernel-arguments os root-device)
          (operating-system-user-kernel-arguments os)))
     (initrd initrd)
     (multiboot-modules multiboot-modules)
     (bootloader-name bootloader-name)
     (bootloader-menu-entries
      (bootloader-configuration-menu-entries (operating-system-bootloader os)))
     (locale locale)
     (store-device (ensure-not-/dev (file-system-device store)))
     (store-directory-prefix (btrfs-store-subvolume-file-name file-systems))
     (store-crypto-devices crypto-devices)
     (store-mount-point (file-system-mount-point store)))))

(define (device->sexp device)
  "Serialize DEVICE as an sexp (really, as an object with a read syntax.)"
  (match device
    ((? uuid? uuid)
     `(uuid ,(uuid-type uuid) ,(uuid-bytevector uuid)))
    ((? file-system-label? label)
     `(file-system-label ,(file-system-label->string label)))
    (_
     device)))

(define* (operating-system-boot-parameters-file os
                                                #:key system-kernel-arguments?)
   "Return a file that describes the boot parameters of OS.  The primary use of
this file is the reconstruction of GRUB menu entries for old configurations.

When SYSTEM-KERNEL-ARGUMENTS? is true, add kernel arguments such as '--root'
and '--load' to the returned file (since the returned file is then usually
stored into the content-addressed \"system\" directory, it's usually not a
good idea to give it because the content hash would change by the content hash
being stored into the \"parameters\" file)."
   (let* ((root   (operating-system-root-file-system os))
          (device (file-system-device root))
          (params (operating-system-boot-parameters
                   os device
                   #:system-kernel-arguments?
                   system-kernel-arguments?)))
     (scheme-file "parameters"
                  #~(boot-parameters
                     (version 0)
                     (label #$(boot-parameters-label params))
                     (root-device
                      #$(device->sexp
                         (boot-parameters-root-device params)))
                     (kernel #$(boot-parameters-kernel params))
                     (kernel-arguments
                      #$(boot-parameters-kernel-arguments params))
                     #$@(if (boot-parameters-initrd params)
                            #~((initrd #$(boot-parameters-initrd params)))
                            #~())
                     #$@(if (pair? (boot-parameters-multiboot-modules params))
                            #~((multiboot-modules
                                #$(boot-parameters-multiboot-modules params)))
                            #~())
                     (bootloader-name #$(boot-parameters-bootloader-name params))
                     (bootloader-menu-entries
                      #$(map menu-entry->sexp
                             (or (and=> (operating-system-bootloader os)
                                        bootloader-configuration-menu-entries)
                                 '())))
                     (locale #$(boot-parameters-locale params))
                     (store
                      (device
                       #$(device->sexp (boot-parameters-store-device params)))
                      (mount-point #$(boot-parameters-store-mount-point
                                      params))
                      (directory-prefix
                       #$(boot-parameters-store-directory-prefix params))
                      (crypto-devices
                       #$(map device->sexp
                              (boot-parameters-store-crypto-devices params)))))
                  #:set-load-path? #f)))

(define-gexp-compiler (operating-system-compiler (os <operating-system>)
                                                 system target)
  ((store-lift
    (lambda (store)
      ;; XXX: This is not super elegant but we can't pass SYSTEM and TARGET to
      ;; 'operating-system-derivation'.
      (run-with-store store (operating-system-derivation os)
                      #:system system
                      #:target target)))))

;;; system.scm ends here