0055a803e2
* gnu/system/file-systems.scm (file-system-mount-point-predicate): Add it. Signed-off-by: Ludovic Courtès <ludo@gnu.org>
744 lines
26 KiB
Scheme
744 lines
26 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2013-2021 Ludovic Courtès <ludo@gnu.org>
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;;; Copyright © 2020 Google LLC
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;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net>
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;;; Copyright © 2020, 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
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;;; Copyright © 2021 Tobias Geerinckx-Rice <me@tobias.gr>
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;;;
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;;; This file is part of GNU Guix.
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;;;
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;;; GNU Guix is free software; you can redistribute it and/or modify it
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;;; under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation; either version 3 of the License, or (at
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;;; your option) any later version.
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;;;
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;;; GNU Guix is distributed in the hope that it will be useful, but
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;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
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(define-module (gnu system file-systems)
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#:use-module (ice-9 match)
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#:use-module (rnrs bytevectors)
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#:use-module (srfi srfi-1)
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#:use-module (srfi srfi-2)
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#:use-module (srfi srfi-9)
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#:use-module (srfi srfi-26)
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#:use-module (srfi srfi-35)
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#:use-module (srfi srfi-9 gnu)
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#:use-module (guix records)
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#:use-module ((guix diagnostics)
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#:select (source-properties->location leave &fix-hint))
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#:use-module (guix i18n)
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#:use-module (gnu system uuid)
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#:re-export (uuid ;backward compatibility
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string->uuid
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uuid->string)
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#:export (file-system
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file-system?
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file-system-device
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file-system-device->string
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file-system-title ;deprecated
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file-system-mount-point
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file-system-type
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file-system-needed-for-boot?
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file-system-flags
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file-system-options
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file-system-options->alist
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alist->file-system-options
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file-system-mount?
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file-system-mount-may-fail?
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file-system-check?
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file-system-skip-check-if-clean?
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file-system-repair
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file-system-create-mount-point?
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file-system-dependencies
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file-system-location
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file-system-type-predicate
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file-system-mount-point-predicate
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btrfs-subvolume?
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btrfs-store-subvolume-file-name
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file-system-label
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file-system-label?
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file-system-label->string
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file-system->spec
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spec->file-system
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specification->file-system-mapping
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%pseudo-file-system-types
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%fuse-control-file-system
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%binary-format-file-system
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%debug-file-system
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%efivars-file-system
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%shared-memory-file-system
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%pseudo-terminal-file-system
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%tty-gid
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%immutable-store
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%control-groups
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%elogind-file-systems
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%base-file-systems
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%container-file-systems
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<file-system-mapping>
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file-system-mapping
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file-system-mapping?
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file-system-mapping-source
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file-system-mapping-target
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file-system-mapping-writable?
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file-system-mapping->bind-mount
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%store-mapping
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%network-configuration-files
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%network-file-mappings
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swap-space
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swap-space?
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swap-space-target
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swap-space-dependencies
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swap-space-priority
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swap-space-discard?))
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;;; Commentary:
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;;;
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;;; Declaring file systems to be mounted.
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;;;
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;;; Note: this file system is used both in the Shepherd and on the "host
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;;; side", so it must not include (gnu packages …) modules.
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;;;
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;;; Code:
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(eval-when (expand load eval)
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(define invalid-file-system-flags
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;; Note: Keep in sync with 'mount-flags->bit-mask'.
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(let ((known-flags '(read-only
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bind-mount no-suid no-dev no-exec
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no-atime strict-atime lazy-time)))
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(lambda (flags)
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"Return the subset of FLAGS that is invalid."
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(remove (cut memq <> known-flags) flags))))
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(define (%validate-file-system-flags flags location)
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"Raise an error if FLAGS contains invalid mount flags; otherwise return
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FLAGS."
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(match (invalid-file-system-flags flags)
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(() flags)
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(invalid
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(leave (source-properties->location location)
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(N_ "invalid file system mount flag:~{ ~s~}~%"
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"invalid file system mount flags:~{ ~s~}~%"
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(length invalid))
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invalid)))))
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(define-syntax validate-file-system-flags
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(lambda (s)
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"Validate the given file system mount flags, raising an error if invalid
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flags are found."
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(syntax-case s (quote)
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((_ (quote (symbols ...))) ;validate at expansion time
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(begin
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(%validate-file-system-flags (syntax->datum #'(symbols ...))
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(syntax-source s))
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#'(quote (symbols ...))))
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((_ flags)
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#`(%validate-file-system-flags flags
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'#,(datum->syntax s (syntax-source s))))
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(id
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(identifier? #'id)
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#'%validate-file-system-flags))))
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;; File system declaration.
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(define-record-type* <file-system> %file-system
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make-file-system
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file-system?
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(device file-system-device) ; string | <uuid> | <file-system-label>
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(mount-point file-system-mount-point) ; string
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(type file-system-type) ; string
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(flags file-system-flags ; list of symbols
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(default '())
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(sanitize validate-file-system-flags))
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(options file-system-options ; string or #f
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(default #f))
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(mount? file-system-mount? ; Boolean
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(default #t))
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(mount-may-fail? file-system-mount-may-fail? ; Boolean
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(default #f))
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(needed-for-boot? %file-system-needed-for-boot? ; Boolean
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(default #f))
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(check? file-system-check? ; Boolean
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(default #t))
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(skip-check-if-clean? file-system-skip-check-if-clean? ; Boolean
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(default #t))
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(repair file-system-repair ; symbol or #f
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(default 'preen))
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(create-mount-point? file-system-create-mount-point? ; Boolean
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(default #f))
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(dependencies file-system-dependencies ; list of <file-system>
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(default '())) ; or <mapped-device>
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(location file-system-location
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(default (current-source-location))
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(innate)))
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;; A file system label for use in the 'device' field.
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(define-record-type <file-system-label>
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(file-system-label label)
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file-system-label?
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(label file-system-label->string))
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(set-record-type-printer! <file-system-label>
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(lambda (obj port)
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(format port "#<file-system-label ~s>"
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(file-system-label->string obj))))
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(define-syntax report-deprecation
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(lambda (s)
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"Report the use of the now-deprecated 'title' field."
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(syntax-case s ()
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((_ field)
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(let* ((source (syntax-source #'field))
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(file (and source (assq-ref source 'filename)))
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(line (and source
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(and=> (assq-ref source 'line) 1+)))
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(column (and source (assq-ref source 'column))))
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(format (current-error-port)
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"~a:~a:~a: warning: 'title' field is deprecated~%"
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file line column)
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#t)))))
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;; Helper for 'process-file-system-declaration'.
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(define-syntax device-expression
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(syntax-rules (quote label uuid device)
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((_ (quote label) dev)
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(file-system-label dev))
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((_ (quote uuid) dev)
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(if (uuid? dev) dev (uuid dev)))
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((_ (quote device) dev)
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dev)
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((_ title dev)
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(case title
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((label) (file-system-label dev))
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((uuid) (uuid dev))
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(else dev)))))
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;; Helper to interpret the now-deprecated 'title' field. Detect forms like
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;; (title 'label), remove them, and adjust the 'device' field accordingly.
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;; TODO: Remove this once 'title' has been deprecated long enough.
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(define-syntax process-file-system-declaration
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(syntax-rules (device title)
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((_ () (rest ...) #f #f) ;no 'title' and no 'device' field
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(%file-system rest ...))
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((_ () (rest ...) dev #f) ;no 'title' field
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(%file-system rest ... (device dev)))
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((_ () (rest ...) dev titl) ;got a 'title' field
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(%file-system rest ...
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(device (device-expression titl dev))))
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((_ ((title titl) rest ...) (previous ...) dev _)
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(begin
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(report-deprecation (title titl))
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(process-file-system-declaration (rest ...)
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(previous ...)
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dev titl)))
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((_ ((device dev) rest ...) (previous ...) _ titl)
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(process-file-system-declaration (rest ...)
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(previous ...)
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dev titl))
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((_ (field rest ...) (previous ...) dev titl)
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(process-file-system-declaration (rest ...)
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(previous ... field)
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dev titl))))
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(define-syntax-rule (file-system fields ...)
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(process-file-system-declaration (fields ...) () #f #f))
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(define (file-system-title fs) ;deprecated
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(match (file-system-device fs)
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((? file-system-label?) 'label)
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((? uuid?) 'uuid)
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((? string?) 'device)))
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;; Note: This module is used both on the build side and on the host side.
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;; Arrange not to pull (guix store) and (guix config) because the latter
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;; differs from user to user.
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(define (%store-prefix)
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"Return the store prefix."
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;; Note: If we have (guix store database) in the search path and we do *not*
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;; have (guix store) proper, 'resolve-module' returns an empty (guix store)
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;; with one sub-module.
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(cond ((and=> (resolve-module '(guix store) #:ensure #f)
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(lambda (store)
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(module-variable store '%store-prefix)))
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=>
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(lambda (variable)
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((variable-ref variable))))
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((getenv "NIX_STORE")
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=> identity)
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(else
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"/gnu/store")))
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(define %not-slash
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(char-set-complement (char-set #\/)))
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(define (file-prefix? file1 file2)
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"Return #t if FILE1 denotes the name of a file that is a parent of FILE2.
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FILE1 and FILE2 must both be either absolute or relative file names, else #f
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is returned.
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For example:
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(file-prefix? \"/gnu\" \"/gnu/store\")
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=> #t
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(file-prefix? \"/gn\" \"/gnu/store\")
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=> #f
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"
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(define (absolute? file)
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(string-prefix? "/" file))
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(if (or (every absolute? (list file1 file2))
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(every (negate absolute?) (list file1 file2)))
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(let loop ((file1 (string-tokenize file1 %not-slash))
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(file2 (string-tokenize file2 %not-slash)))
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(match file1
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(()
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#t)
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((head1 tail1 ...)
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(match file2
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((head2 tail2 ...)
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(and (string=? head1 head2) (loop tail1 tail2)))
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(()
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#f)))))
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;; FILE1 and FILE2 are a mix of absolute and relative file names.
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#f))
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(define (file-name-depth file-name)
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(length (string-tokenize file-name %not-slash)))
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(define* (file-system-device->string device #:key uuid-type)
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"Return the string representations of the DEVICE field of a <file-system>
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record. When the device is a UUID, its representation is chosen depending on
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UUID-TYPE, a symbol such as 'dce or 'iso9660."
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(match device
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((? file-system-label?)
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(file-system-label->string device))
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((? uuid?)
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(if uuid-type
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(uuid->string (uuid-bytevector device) uuid-type)
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(uuid->string device)))
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((? string?)
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device)))
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(define (file-system-options->alist string)
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"Translate the option string format of a <file-system> record into an
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association list of options or option/value pairs."
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(if string
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(let ((options (string-split string #\,)))
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(map (lambda (param)
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(let ((=index (string-index param #\=)))
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(if =index
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(cons (string-take param =index)
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(string-drop param (1+ =index)))
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param)))
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options))
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'()))
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(define (alist->file-system-options options)
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"Return the string representation of OPTIONS, an association list. The
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string obtained can be used as the option field of a <file-system> record."
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(if (null? options)
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#f
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(string-join (map (match-lambda
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((key . value)
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(string-append key "=" value))
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(key
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key))
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options)
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",")))
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(define (file-system-needed-for-boot? fs)
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"Return true if FS has the 'needed-for-boot?' flag set, or if it holds the
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store--e.g., if FS is the root file system."
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(or (%file-system-needed-for-boot? fs)
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(and (file-prefix? (file-system-mount-point fs) (%store-prefix))
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(not (memq 'bind-mount (file-system-flags fs))))))
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(define (file-system->spec fs)
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"Return a list corresponding to file-system FS that can be passed to the
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initrd code."
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(match fs
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(($ <file-system> device mount-point type flags options mount?
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mount-may-fail? needed-for-boot?
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check? skip-check-if-clean? repair)
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;; Note: Add new fields towards the end for compatibility.
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(list (cond ((uuid? device)
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`(uuid ,(uuid-type device) ,(uuid-bytevector device)))
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((file-system-label? device)
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`(file-system-label ,(file-system-label->string device)))
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(else device))
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mount-point type flags options mount-may-fail?
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check? skip-check-if-clean? repair))))
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(define (spec->file-system sexp)
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"Deserialize SEXP, a list, to the corresponding <file-system> object."
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(match sexp
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((device mount-point type flags options mount-may-fail?
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check? skip-check-if-clean? repair
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_ ...) ;placeholder for new fields
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(file-system
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(device (match device
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(('uuid (? symbol? type) (? bytevector? bv))
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(bytevector->uuid bv type))
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(('file-system-label (? string? label))
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(file-system-label label))
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(_
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device)))
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(mount-point mount-point) (type type)
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(flags flags) (options options)
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(mount-may-fail? mount-may-fail?)
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(check? check?)
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(skip-check-if-clean? skip-check-if-clean?)
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(repair repair)))))
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(define (specification->file-system-mapping spec writable?)
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"Read the SPEC and return the corresponding <file-system-mapping>. SPEC is
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a string of the form \"SOURCE\" or \"SOURCE=TARGET\". The former specifies
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that SOURCE from the host should be mounted at SOURCE in the other system.
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The latter format specifies that SOURCE from the host should be mounted at
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TARGET in the other system."
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(let ((index (string-index spec #\=)))
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(if index
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(file-system-mapping
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(source (substring spec 0 index))
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(target (substring spec (+ 1 index)))
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(writable? writable?))
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(file-system-mapping
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(source spec)
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(target spec)
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(writable? writable?)))))
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;;;
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;;; Common file systems.
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;;;
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(define %pseudo-file-system-types
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;; List of know pseudo file system types. This is used when validating file
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;; system definitions.
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'("binfmt_misc" "cgroup" "debugfs" "devpts" "devtmpfs" "efivarfs" "fusectl"
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"hugetlbfs" "overlay" "proc" "securityfs" "sysfs" "tmpfs"))
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(define %fuse-control-file-system
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;; Control file system for Linux' file systems in user-space (FUSE).
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(file-system
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(device "fusectl")
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(mount-point "/sys/fs/fuse/connections")
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(type "fusectl")
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(check? #f)))
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(define %binary-format-file-system
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;; Support for arbitrary executable binary format.
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(file-system
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(device "binfmt_misc")
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(mount-point "/proc/sys/fs/binfmt_misc")
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(type "binfmt_misc")
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(check? #f)))
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(define %debug-file-system
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(file-system
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(type "debugfs")
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(device "none")
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(mount-point "/sys/kernel/debug")
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(check? #f)
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(create-mount-point? #t)))
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(define %efivars-file-system
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;; Support for EFI variables file system.
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(file-system
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(device "efivarfs")
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(mount-point "/sys/firmware/efi/efivars")
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(type "efivarfs")
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(mount-may-fail? #t)
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(needed-for-boot? #f)
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(check? #f)))
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(define %tty-gid
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;; ID of the 'tty' group. Allocate it statically to make it easy to refer
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;; to it from here and from the 'tty' group definitions.
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996)
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(define %pseudo-terminal-file-system
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;; The pseudo-terminal file system. It needs to be mounted so that
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;; statfs(2) returns DEVPTS_SUPER_MAGIC like libc's getpt(3) expects (and
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;; thus openpty(3) and its users, such as xterm.)
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(file-system
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(device "none")
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(mount-point "/dev/pts")
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(type "devpts")
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(check? #f)
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(needed-for-boot? #f)
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(create-mount-point? #t)
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(options (string-append "gid=" (number->string %tty-gid) ",mode=620"))))
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(define %shared-memory-file-system
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;; Shared memory.
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(file-system
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(device "tmpfs")
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(mount-point "/dev/shm")
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(type "tmpfs")
|
||
(check? #f)
|
||
(flags '(no-suid no-dev))
|
||
(options "size=50%") ;TODO: make size configurable
|
||
(create-mount-point? #t)))
|
||
|
||
(define %immutable-store
|
||
;; Read-only store to avoid users or daemons accidentally modifying it.
|
||
;; 'guix-daemon' has provisions to remount it read-write in its own name
|
||
;; space.
|
||
(file-system
|
||
(device (%store-prefix))
|
||
(mount-point (%store-prefix))
|
||
(type "none")
|
||
(check? #f)
|
||
(flags '(read-only bind-mount no-atime))))
|
||
|
||
(define %control-groups
|
||
(let ((parent (file-system
|
||
(device "cgroup")
|
||
(mount-point "/sys/fs/cgroup")
|
||
(type "tmpfs")
|
||
(check? #f))))
|
||
(cons parent
|
||
(map (lambda (subsystem)
|
||
(file-system
|
||
(device "cgroup")
|
||
(mount-point (string-append "/sys/fs/cgroup/" subsystem))
|
||
(type "cgroup")
|
||
(check? #f)
|
||
(options subsystem)
|
||
(create-mount-point? #t)
|
||
|
||
;; This must be mounted after, and unmounted before the
|
||
;; parent directory.
|
||
(dependencies (list parent))))
|
||
'("cpuset" "cpu" "cpuacct" "memory" "devices" "freezer"
|
||
"blkio" "perf_event" "pids")))))
|
||
|
||
(define %elogind-file-systems
|
||
;; We don't use systemd, but these file systems are needed for elogind,
|
||
;; which was extracted from systemd.
|
||
(append
|
||
(list (file-system
|
||
(device "none")
|
||
(mount-point "/run/systemd")
|
||
(type "tmpfs")
|
||
(check? #f)
|
||
(flags '(no-suid no-dev no-exec))
|
||
(options "mode=0755")
|
||
(create-mount-point? #t))
|
||
(file-system
|
||
(device "none")
|
||
(mount-point "/run/user")
|
||
(type "tmpfs")
|
||
(check? #f)
|
||
(flags '(no-suid no-dev no-exec))
|
||
(options "mode=0755")
|
||
(create-mount-point? #t))
|
||
;; Elogind uses cgroups to organize processes, allowing it to map PIDs
|
||
;; to sessions. Elogind's cgroup hierarchy isn't associated with any
|
||
;; resource controller ("subsystem").
|
||
(file-system
|
||
(device "cgroup")
|
||
(mount-point "/sys/fs/cgroup/elogind")
|
||
(type "cgroup")
|
||
(check? #f)
|
||
(options "none,name=elogind")
|
||
(create-mount-point? #t)
|
||
(dependencies (list (car %control-groups)))))
|
||
%control-groups))
|
||
|
||
(define %base-file-systems
|
||
;; List of basic file systems to be mounted. Note that /proc and /sys are
|
||
;; currently mounted by the initrd.
|
||
(list %pseudo-terminal-file-system
|
||
%debug-file-system
|
||
%shared-memory-file-system
|
||
%efivars-file-system
|
||
%immutable-store))
|
||
|
||
;; File systems for Linux containers differ from %base-file-systems in that
|
||
;; they impose additional restrictions such as no-exec or need different
|
||
;; options to function properly.
|
||
;;
|
||
;; The file system flags and options conform to the libcontainer
|
||
;; specification:
|
||
;; https://github.com/docker/libcontainer/blob/master/SPEC.md#filesystem
|
||
(define %container-file-systems
|
||
(list
|
||
;; Pseudo-terminal file system.
|
||
(file-system
|
||
(device "none")
|
||
(mount-point "/dev/pts")
|
||
(type "devpts")
|
||
(flags '(no-exec no-suid))
|
||
(needed-for-boot? #t)
|
||
(create-mount-point? #t)
|
||
(check? #f)
|
||
(options "newinstance,ptmxmode=0666,mode=620"))
|
||
;; Shared memory file system.
|
||
(file-system
|
||
(device "tmpfs")
|
||
(mount-point "/dev/shm")
|
||
(type "tmpfs")
|
||
(flags '(no-exec no-suid no-dev))
|
||
(options "mode=1777,size=65536k")
|
||
(needed-for-boot? #t)
|
||
(create-mount-point? #t)
|
||
(check? #f))
|
||
;; Message queue file system.
|
||
(file-system
|
||
(device "mqueue")
|
||
(mount-point "/dev/mqueue")
|
||
(type "mqueue")
|
||
(flags '(no-exec no-suid no-dev))
|
||
(needed-for-boot? #t)
|
||
(create-mount-point? #t)
|
||
(check? #f))))
|
||
|
||
|
||
;;;
|
||
;;; Shared file systems, for VMs/containers.
|
||
;;;
|
||
|
||
;; Mapping of host file system SOURCE to mount point TARGET in the guest.
|
||
(define-record-type* <file-system-mapping> file-system-mapping
|
||
make-file-system-mapping
|
||
file-system-mapping?
|
||
(source file-system-mapping-source) ;string
|
||
(target file-system-mapping-target) ;string
|
||
(writable? file-system-mapping-writable? ;Boolean
|
||
(default #f)))
|
||
|
||
(define (file-system-mapping->bind-mount mapping)
|
||
"Return a file system that realizes MAPPING, a <file-system-mapping>, using
|
||
a bind mount."
|
||
(match mapping
|
||
(($ <file-system-mapping> source target writable?)
|
||
(file-system
|
||
(mount-point target)
|
||
(device source)
|
||
(type "none")
|
||
(flags (if writable?
|
||
'(bind-mount)
|
||
'(bind-mount read-only)))
|
||
(check? #f)
|
||
(create-mount-point? #t)))))
|
||
|
||
(define %store-mapping
|
||
;; Mapping of the host's store into the guest.
|
||
(file-system-mapping
|
||
(source (%store-prefix))
|
||
(target (%store-prefix))
|
||
(writable? #f)))
|
||
|
||
(define %network-configuration-files
|
||
;; List of essential network configuration files.
|
||
'("/etc/resolv.conf"
|
||
"/etc/nsswitch.conf"
|
||
"/etc/services"
|
||
"/etc/hosts"))
|
||
|
||
(define %network-file-mappings
|
||
;; List of file mappings for essential network files.
|
||
(filter-map (lambda (file)
|
||
(file-system-mapping
|
||
(source file)
|
||
(target file)
|
||
;; XXX: On some GNU/Linux systems, /etc/resolv.conf is a
|
||
;; symlink to a file in a tmpfs which, for an unknown reason,
|
||
;; cannot be bind mounted read-only within the container.
|
||
(writable? (string=? file "/etc/resolv.conf"))))
|
||
%network-configuration-files))
|
||
|
||
(define (file-system-type-predicate type)
|
||
"Return a predicate that, when passed a file system, returns #t if that file
|
||
system has the given TYPE."
|
||
(lambda (fs)
|
||
(string=? (file-system-type fs) type)))
|
||
|
||
(define (file-system-mount-point-predicate mount-point)
|
||
"Return a predicate that, when passed a file system, returns #t if that file
|
||
system has the given MOUNT-POINT."
|
||
(lambda (fs)
|
||
(string=? (file-system-mount-point fs) mount-point)))
|
||
|
||
|
||
;;;
|
||
;;; Btrfs specific helpers.
|
||
;;;
|
||
|
||
(define (btrfs-subvolume? fs)
|
||
"Predicate to check if FS, a file-system object, is a Btrfs subvolume."
|
||
(and-let* ((btrfs-file-system? (string= "btrfs" (file-system-type fs)))
|
||
(option-keys (map (match-lambda
|
||
((key . value) key)
|
||
(key key))
|
||
(file-system-options->alist
|
||
(file-system-options fs)))))
|
||
(find (cut string-prefix? "subvol" <>) option-keys)))
|
||
|
||
(define (btrfs-store-subvolume-file-name file-systems)
|
||
"Return the subvolume file name within the Btrfs top level onto which the
|
||
store is located, else #f."
|
||
|
||
(define (prepend-slash/maybe s)
|
||
(if (string=? "/" (string-take s 1))
|
||
s
|
||
(string-append "/" s)))
|
||
|
||
(and-let* ((btrfs-subvolume-fs (filter btrfs-subvolume? file-systems))
|
||
(btrfs-subvolume-fs*
|
||
(sort btrfs-subvolume-fs
|
||
(lambda (fs1 fs2)
|
||
(> (file-name-depth (file-system-mount-point fs1))
|
||
(file-name-depth (file-system-mount-point fs2))))))
|
||
(store-subvolume-fs
|
||
(find (lambda (fs) (file-prefix? (file-system-mount-point fs)
|
||
(%store-prefix)))
|
||
btrfs-subvolume-fs*))
|
||
(options (file-system-options->alist
|
||
(file-system-options store-subvolume-fs))))
|
||
;; XXX: Deriving the subvolume name based from a subvolume ID is not
|
||
;; supported, as we'd need to query the actual file system.
|
||
(or (and=> (assoc-ref options "subvol") prepend-slash/maybe)
|
||
(raise (condition
|
||
(&message
|
||
(message "The store is on a Btrfs subvolume, but the \
|
||
subvolume name is unknown."))
|
||
(&fix-hint
|
||
(hint
|
||
(G_ "Use the @code{subvol} Btrfs file system option."))))))))
|
||
|
||
|
||
;;;
|
||
;;; Swap space
|
||
;;;
|
||
|
||
(define-record-type* <swap-space> swap-space make-swap-space
|
||
swap-space?
|
||
this-swap-space
|
||
(target swap-space-target)
|
||
(dependencies swap-space-dependencies
|
||
(default '()))
|
||
(priority swap-space-priority
|
||
(default #f))
|
||
(discard? swap-space-discard?
|
||
(default #f)))
|
||
|
||
;;; file-systems.scm ends here
|