4b49487838
* gnu/build/file-systems.scm (mount-flags->bit-mask, mount-file-system): Handle shared flag. * gnu/system/file-systems.scm (invalid-file-system-flags): Add shared to known flags. * guix/build/syscalls.scm (MS_SHARED): New variable. * doc/guix.texi (File Systems): Document shared flag.
748 lines
26 KiB
Scheme
748 lines
26 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
|
||
;;; Copyright © 2013-2022 Ludovic Courtès <ludo@gnu.org>
|
||
;;; Copyright © 2020 Google LLC
|
||
;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net>
|
||
;;; Copyright © 2020, 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
|
||
;;; Copyright © 2021 Tobias Geerinckx-Rice <me@tobias.gr>
|
||
;;; Copyright © 2022 Oleg Pykhalov <go.wigust@gmail.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 file-systems)
|
||
#:use-module (ice-9 match)
|
||
#:use-module (rnrs bytevectors)
|
||
#:use-module (srfi srfi-1)
|
||
#:use-module (srfi srfi-2)
|
||
#:use-module (srfi srfi-9)
|
||
#:use-module (srfi srfi-26)
|
||
#:use-module (srfi srfi-35)
|
||
#:use-module (srfi srfi-9 gnu)
|
||
#:use-module (guix records)
|
||
#:use-module ((guix diagnostics)
|
||
#:select (source-properties->location leave &fix-hint))
|
||
#:use-module (guix i18n)
|
||
#:use-module (gnu system uuid)
|
||
#:re-export (uuid ;backward compatibility
|
||
string->uuid
|
||
uuid->string)
|
||
#:export (file-system
|
||
file-system?
|
||
file-system-device
|
||
file-system-device->string
|
||
file-system-title ;deprecated
|
||
file-system-mount-point
|
||
file-system-type
|
||
file-system-needed-for-boot?
|
||
file-system-flags
|
||
file-system-options
|
||
file-system-options->alist
|
||
alist->file-system-options
|
||
|
||
file-system-mount?
|
||
file-system-mount-may-fail?
|
||
file-system-check?
|
||
file-system-skip-check-if-clean?
|
||
file-system-repair
|
||
file-system-create-mount-point?
|
||
file-system-dependencies
|
||
file-system-location
|
||
|
||
file-system-type-predicate
|
||
file-system-mount-point-predicate
|
||
btrfs-subvolume?
|
||
btrfs-store-subvolume-file-name
|
||
|
||
file-system-label
|
||
file-system-label?
|
||
file-system-label->string
|
||
|
||
file-system->spec
|
||
spec->file-system
|
||
specification->file-system-mapping
|
||
|
||
%pseudo-file-system-types
|
||
%fuse-control-file-system
|
||
%binary-format-file-system
|
||
%debug-file-system
|
||
%efivars-file-system
|
||
%shared-memory-file-system
|
||
%pseudo-terminal-file-system
|
||
%tty-gid
|
||
%immutable-store
|
||
%control-groups
|
||
%elogind-file-systems
|
||
|
||
%base-file-systems
|
||
%container-file-systems
|
||
|
||
<file-system-mapping>
|
||
file-system-mapping
|
||
file-system-mapping?
|
||
file-system-mapping-source
|
||
file-system-mapping-target
|
||
file-system-mapping-writable?
|
||
|
||
file-system-mapping->bind-mount
|
||
|
||
%store-mapping
|
||
%network-configuration-files
|
||
%network-file-mappings
|
||
|
||
swap-space
|
||
swap-space?
|
||
swap-space-target
|
||
swap-space-dependencies
|
||
swap-space-priority
|
||
swap-space-discard?))
|
||
|
||
;;; Commentary:
|
||
;;;
|
||
;;; Declaring file systems to be mounted.
|
||
;;;
|
||
;;; Note: this file system is used both in the Shepherd and on the "host
|
||
;;; side", so it must not include (gnu packages …) modules.
|
||
;;;
|
||
;;; Code:
|
||
|
||
(eval-when (expand load eval)
|
||
(define invalid-file-system-flags
|
||
;; Note: Keep in sync with 'mount-flags->bit-mask'.
|
||
(let ((known-flags '(read-only
|
||
bind-mount no-suid no-dev no-exec
|
||
no-atime strict-atime lazy-time
|
||
shared)))
|
||
(lambda (flags)
|
||
"Return the subset of FLAGS that is invalid."
|
||
(remove (cut memq <> known-flags) flags))))
|
||
|
||
(define (%validate-file-system-flags flags location)
|
||
"Raise an error if FLAGS contains invalid mount flags; otherwise return
|
||
FLAGS."
|
||
(match (invalid-file-system-flags flags)
|
||
(() flags)
|
||
(invalid
|
||
(leave (source-properties->location location)
|
||
(N_ "invalid file system mount flag:~{ ~s~}~%"
|
||
"invalid file system mount flags:~{ ~s~}~%"
|
||
(length invalid))
|
||
invalid)))))
|
||
|
||
(define-syntax validate-file-system-flags
|
||
(lambda (s)
|
||
"Validate the given file system mount flags, raising an error if invalid
|
||
flags are found."
|
||
(syntax-case s (quote)
|
||
((_ (quote (symbols ...))) ;validate at expansion time
|
||
(begin
|
||
(%validate-file-system-flags (syntax->datum #'(symbols ...))
|
||
(syntax-source s))
|
||
#'(quote (symbols ...))))
|
||
((_ flags)
|
||
#`(%validate-file-system-flags flags
|
||
'#,(datum->syntax s (syntax-source s))))
|
||
(id
|
||
(identifier? #'id)
|
||
#'%validate-file-system-flags))))
|
||
|
||
;; File system declaration.
|
||
(define-record-type* <file-system> %file-system
|
||
make-file-system
|
||
file-system?
|
||
(device file-system-device) ; string | <uuid> | <file-system-label>
|
||
(mount-point file-system-mount-point) ; string
|
||
(type file-system-type) ; string
|
||
(flags file-system-flags ; list of symbols
|
||
(default '())
|
||
(sanitize validate-file-system-flags))
|
||
(options file-system-options ; string or #f
|
||
(default #f))
|
||
(mount? file-system-mount? ; Boolean
|
||
(default #t))
|
||
(mount-may-fail? file-system-mount-may-fail? ; Boolean
|
||
(default #f))
|
||
(needed-for-boot? %file-system-needed-for-boot? ; Boolean
|
||
(default #f))
|
||
(check? file-system-check? ; Boolean
|
||
(default #t))
|
||
(skip-check-if-clean? file-system-skip-check-if-clean? ; Boolean
|
||
(default #t))
|
||
(repair file-system-repair ; symbol or #f
|
||
(default 'preen))
|
||
(create-mount-point? file-system-create-mount-point? ; Boolean
|
||
(default #f))
|
||
(dependencies file-system-dependencies ; list of <file-system>
|
||
(default '())) ; or <mapped-device>
|
||
(location file-system-location
|
||
(default (current-source-location))
|
||
(innate)))
|
||
|
||
;; A file system label for use in the 'device' field.
|
||
(define-record-type <file-system-label>
|
||
(file-system-label label)
|
||
file-system-label?
|
||
(label file-system-label->string))
|
||
|
||
(set-record-type-printer! <file-system-label>
|
||
(lambda (obj port)
|
||
(format port "#<file-system-label ~s>"
|
||
(file-system-label->string obj))))
|
||
|
||
(define-syntax report-deprecation
|
||
(lambda (s)
|
||
"Report the use of the now-deprecated 'title' field."
|
||
(syntax-case s ()
|
||
((_ field)
|
||
(let* ((source (syntax-source #'field))
|
||
(file (and source (assq-ref source 'filename)))
|
||
(line (and source
|
||
(and=> (assq-ref source 'line) 1+)))
|
||
(column (and source (assq-ref source 'column))))
|
||
(format (current-error-port)
|
||
"~a:~a:~a: warning: 'title' field is deprecated~%"
|
||
file line column)
|
||
#t)))))
|
||
|
||
;; Helper for 'process-file-system-declaration'.
|
||
(define-syntax device-expression
|
||
(syntax-rules (quote label uuid device)
|
||
((_ (quote label) dev)
|
||
(file-system-label dev))
|
||
((_ (quote uuid) dev)
|
||
(if (uuid? dev) dev (uuid dev)))
|
||
((_ (quote device) dev)
|
||
dev)
|
||
((_ title dev)
|
||
(case title
|
||
((label) (file-system-label dev))
|
||
((uuid) (uuid dev))
|
||
(else dev)))))
|
||
|
||
;; Helper to interpret the now-deprecated 'title' field. Detect forms like
|
||
;; (title 'label), remove them, and adjust the 'device' field accordingly.
|
||
;; TODO: Remove this once 'title' has been deprecated long enough.
|
||
(define-syntax process-file-system-declaration
|
||
(syntax-rules (device title)
|
||
((_ () (rest ...) #f #f) ;no 'title' and no 'device' field
|
||
(%file-system rest ...))
|
||
((_ () (rest ...) dev #f) ;no 'title' field
|
||
(%file-system rest ... (device dev)))
|
||
((_ () (rest ...) dev titl) ;got a 'title' field
|
||
(%file-system rest ...
|
||
(device (device-expression titl dev))))
|
||
((_ ((title titl) rest ...) (previous ...) dev _)
|
||
(begin
|
||
(report-deprecation (title titl))
|
||
(process-file-system-declaration (rest ...)
|
||
(previous ...)
|
||
dev titl)))
|
||
((_ ((device dev) rest ...) (previous ...) _ titl)
|
||
(process-file-system-declaration (rest ...)
|
||
(previous ...)
|
||
dev titl))
|
||
((_ (field rest ...) (previous ...) dev titl)
|
||
(process-file-system-declaration (rest ...)
|
||
(previous ... field)
|
||
dev titl))))
|
||
|
||
(define-syntax-rule (file-system fields ...)
|
||
(process-file-system-declaration (fields ...) () #f #f))
|
||
|
||
(define (file-system-title fs) ;deprecated
|
||
(match (file-system-device fs)
|
||
((? file-system-label?) 'label)
|
||
((? uuid?) 'uuid)
|
||
((? string?) 'device)))
|
||
|
||
;; Note: This module is used both on the build side and on the host side.
|
||
;; Arrange not to pull (guix store) and (guix config) because the latter
|
||
;; differs from user to user.
|
||
(define (%store-prefix)
|
||
"Return the store prefix."
|
||
;; Note: If we have (guix store database) in the search path and we do *not*
|
||
;; have (guix store) proper, 'resolve-module' returns an empty (guix store)
|
||
;; with one sub-module.
|
||
(cond ((and=> (parameterize ((current-warning-port (%make-void-port "w0")))
|
||
(resolve-module '(guix store) #:ensure #f))
|
||
(lambda (store)
|
||
(module-variable store '%store-prefix)))
|
||
=>
|
||
(lambda (variable)
|
||
((variable-ref variable))))
|
||
((getenv "NIX_STORE")
|
||
=> identity)
|
||
(else
|
||
"/gnu/store")))
|
||
|
||
(define %not-slash
|
||
(char-set-complement (char-set #\/)))
|
||
|
||
(define (file-prefix? file1 file2)
|
||
"Return #t if FILE1 denotes the name of a file that is a parent of FILE2.
|
||
FILE1 and FILE2 must both be either absolute or relative file names, else #f
|
||
is returned.
|
||
|
||
For example:
|
||
|
||
(file-prefix? \"/gnu\" \"/gnu/store\")
|
||
=> #t
|
||
|
||
(file-prefix? \"/gn\" \"/gnu/store\")
|
||
=> #f
|
||
"
|
||
(define (absolute? file)
|
||
(string-prefix? "/" file))
|
||
|
||
(if (or (every absolute? (list file1 file2))
|
||
(every (negate absolute?) (list file1 file2)))
|
||
(let loop ((file1 (string-tokenize file1 %not-slash))
|
||
(file2 (string-tokenize file2 %not-slash)))
|
||
(match file1
|
||
(()
|
||
#t)
|
||
((head1 tail1 ...)
|
||
(match file2
|
||
((head2 tail2 ...)
|
||
(and (string=? head1 head2) (loop tail1 tail2)))
|
||
(()
|
||
#f)))))
|
||
;; FILE1 and FILE2 are a mix of absolute and relative file names.
|
||
#f))
|
||
|
||
(define (file-name-depth file-name)
|
||
(length (string-tokenize file-name %not-slash)))
|
||
|
||
(define* (file-system-device->string device #:key uuid-type)
|
||
"Return the string representations of the DEVICE field of a <file-system>
|
||
record. When the device is a UUID, its representation is chosen depending on
|
||
UUID-TYPE, a symbol such as 'dce or 'iso9660."
|
||
(match device
|
||
((? file-system-label?)
|
||
(file-system-label->string device))
|
||
((? uuid?)
|
||
(if uuid-type
|
||
(uuid->string (uuid-bytevector device) uuid-type)
|
||
(uuid->string device)))
|
||
((? string?)
|
||
device)))
|
||
|
||
(define (file-system-options->alist string)
|
||
"Translate the option string format of a <file-system> record into an
|
||
association list of options or option/value pairs."
|
||
(if string
|
||
(let ((options (string-split string #\,)))
|
||
(map (lambda (param)
|
||
(let ((=index (string-index param #\=)))
|
||
(if =index
|
||
(cons (string-take param =index)
|
||
(string-drop param (1+ =index)))
|
||
param)))
|
||
options))
|
||
'()))
|
||
|
||
(define (alist->file-system-options options)
|
||
"Return the string representation of OPTIONS, an association list. The
|
||
string obtained can be used as the option field of a <file-system> record."
|
||
(if (null? options)
|
||
#f
|
||
(string-join (map (match-lambda
|
||
((key . value)
|
||
(string-append key "=" value))
|
||
(key
|
||
key))
|
||
options)
|
||
",")))
|
||
|
||
(define (file-system-needed-for-boot? fs)
|
||
"Return true if FS has the 'needed-for-boot?' flag set, or if it holds the
|
||
store--e.g., if FS is the root file system."
|
||
(or (%file-system-needed-for-boot? fs)
|
||
(and (file-prefix? (file-system-mount-point fs) (%store-prefix))
|
||
(not (memq 'bind-mount (file-system-flags fs))))))
|
||
|
||
(define (file-system->spec fs)
|
||
"Return a list corresponding to file-system FS that can be passed to the
|
||
initrd code."
|
||
(match fs
|
||
(($ <file-system> device mount-point type flags options mount?
|
||
mount-may-fail? needed-for-boot?
|
||
check? skip-check-if-clean? repair)
|
||
;; Note: Add new fields towards the end for compatibility.
|
||
(list (cond ((uuid? device)
|
||
`(uuid ,(uuid-type device) ,(uuid-bytevector device)))
|
||
((file-system-label? device)
|
||
`(file-system-label ,(file-system-label->string device)))
|
||
(else device))
|
||
mount-point type flags options mount-may-fail?
|
||
check? skip-check-if-clean? repair))))
|
||
|
||
(define (spec->file-system sexp)
|
||
"Deserialize SEXP, a list, to the corresponding <file-system> object."
|
||
(match sexp
|
||
((device mount-point type flags options mount-may-fail?
|
||
check? skip-check-if-clean? repair
|
||
_ ...) ;placeholder for new fields
|
||
(file-system
|
||
(device (match device
|
||
(('uuid (? symbol? type) (? bytevector? bv))
|
||
(bytevector->uuid bv type))
|
||
(('file-system-label (? string? label))
|
||
(file-system-label label))
|
||
(_
|
||
device)))
|
||
(mount-point mount-point) (type type)
|
||
(flags flags) (options options)
|
||
(mount-may-fail? mount-may-fail?)
|
||
(check? check?)
|
||
(skip-check-if-clean? skip-check-if-clean?)
|
||
(repair repair)))))
|
||
|
||
(define (specification->file-system-mapping spec writable?)
|
||
"Read the SPEC and return the corresponding <file-system-mapping>. SPEC is
|
||
a string of the form \"SOURCE\" or \"SOURCE=TARGET\". The former specifies
|
||
that SOURCE from the host should be mounted at SOURCE in the other system.
|
||
The latter format specifies that SOURCE from the host should be mounted at
|
||
TARGET in the other system."
|
||
(let ((index (string-index spec #\=)))
|
||
(if index
|
||
(file-system-mapping
|
||
(source (substring spec 0 index))
|
||
(target (substring spec (+ 1 index)))
|
||
(writable? writable?))
|
||
(file-system-mapping
|
||
(source spec)
|
||
(target spec)
|
||
(writable? writable?)))))
|
||
|
||
|
||
;;;
|
||
;;; Common file systems.
|
||
;;;
|
||
|
||
(define %pseudo-file-system-types
|
||
;; List of know pseudo file system types. This is used when validating file
|
||
;; system definitions.
|
||
'("binfmt_misc" "cgroup" "debugfs" "devpts" "devtmpfs" "efivarfs" "fusectl"
|
||
"hugetlbfs" "overlay" "proc" "securityfs" "sysfs" "tmpfs"))
|
||
|
||
(define %fuse-control-file-system
|
||
;; Control file system for Linux' file systems in user-space (FUSE).
|
||
(file-system
|
||
(device "fusectl")
|
||
(mount-point "/sys/fs/fuse/connections")
|
||
(type "fusectl")
|
||
(check? #f)))
|
||
|
||
(define %binary-format-file-system
|
||
;; Support for arbitrary executable binary format.
|
||
(file-system
|
||
(device "binfmt_misc")
|
||
(mount-point "/proc/sys/fs/binfmt_misc")
|
||
(type "binfmt_misc")
|
||
(check? #f)))
|
||
|
||
(define %debug-file-system
|
||
(file-system
|
||
(type "debugfs")
|
||
(device "none")
|
||
(mount-point "/sys/kernel/debug")
|
||
(check? #f)
|
||
(create-mount-point? #t)))
|
||
|
||
(define %efivars-file-system
|
||
;; Support for EFI variables file system.
|
||
(file-system
|
||
(device "efivarfs")
|
||
(mount-point "/sys/firmware/efi/efivars")
|
||
(type "efivarfs")
|
||
(mount-may-fail? #t)
|
||
(needed-for-boot? #f)
|
||
(check? #f)))
|
||
|
||
(define %tty-gid
|
||
;; ID of the 'tty' group. Allocate it statically to make it easy to refer
|
||
;; to it from here and from the 'tty' group definitions.
|
||
996)
|
||
|
||
(define %pseudo-terminal-file-system
|
||
;; The pseudo-terminal file system. It needs to be mounted so that
|
||
;; statfs(2) returns DEVPTS_SUPER_MAGIC like libc's getpt(3) expects (and
|
||
;; thus openpty(3) and its users, such as xterm.)
|
||
(file-system
|
||
(device "none")
|
||
(mount-point "/dev/pts")
|
||
(type "devpts")
|
||
(check? #f)
|
||
(needed-for-boot? #f)
|
||
(create-mount-point? #t)
|
||
(options (string-append "gid=" (number->string %tty-gid) ",mode=620"))))
|
||
|
||
(define %shared-memory-file-system
|
||
;; Shared memory.
|
||
(file-system
|
||
(device "tmpfs")
|
||
(mount-point "/dev/shm")
|
||
(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
|