guix/gnu/system/file-systems.scm

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
;;;
;;; 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 (guix records)
#:use-module (guix store)
#:use-module ((gnu build file-systems)
#:select (string->uuid uuid->string))
#:re-export (string->uuid
uuid->string)
#:export (<file-system>
file-system
file-system?
file-system-device
file-system-title
file-system-mount-point
file-system-type
file-system-needed-for-boot?
file-system-flags
file-system-options
file-system-mount?
file-system-check?
file-system-create-mount-point?
file-system-dependencies
file-system->spec
uuid
%fuse-control-file-system
%binary-format-file-system
%shared-memory-file-system
%pseudo-terminal-file-system
%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?
%store-mapping))
;;; Commentary:
;;;
;;; Declaring file systems to be mounted.
;;;
;;; Code:
;; File system declaration.
(define-record-type* <file-system> file-system
make-file-system
file-system?
(device file-system-device) ; string
(title file-system-title ; 'device | 'label | 'uuid
(default 'device))
(mount-point file-system-mount-point) ; string
(type file-system-type) ; string
(flags file-system-flags ; list of symbols
(default '()))
(options file-system-options ; string or #f
(default #f))
(mount? file-system-mount? ; Boolean
(default #t))
(needed-for-boot? %file-system-needed-for-boot? ; Boolean
(default #f))
(check? file-system-check? ; Boolean
(default #t))
(create-mount-point? file-system-create-mount-point? ; Boolean
(default #f))
(dependencies file-system-dependencies ; list of <file-system>
(default '()))) ; or <mapped-device>
(define-inlinable (file-system-needed-for-boot? fs)
"Return true if FS has the 'needed-for-boot?' flag set, or if it's the root
file system."
(or (%file-system-needed-for-boot? fs)
(string=? "/" (file-system-mount-point 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 title mount-point type flags options _ _ check?)
(list device title mount-point type flags options check?))))
(define-syntax uuid
(lambda (s)
"Return the bytevector corresponding to the given UUID representation."
(syntax-case s ()
((_ str)
(string? (syntax->datum #'str))
;; A literal string: do the conversion at expansion time.
(let ((bv (string->uuid (syntax->datum #'str))))
(unless bv
(syntax-violation 'uuid "invalid UUID" s))
(datum->syntax #'str bv)))
((_ str)
#'(string->uuid str)))))
;;;
;;; Common file systems.
;;;
(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 %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))))
(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" "hugetlb")))))
(define %elogind-file-systems
;; We don't use systemd, but these file systems are needed for elogind,
;; which was extracted from systemd.
(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))))))
(define %base-file-systems
;; List of basic file systems to be mounted. Note that /proc and /sys are
;; currently mounted by the initrd.
(append (list %pseudo-terminal-file-system
%shared-memory-file-system
%immutable-store)
%elogind-file-systems
%control-groups))
;; 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 %store-mapping
;; Mapping of the host's store into the guest.
(file-system-mapping
(source (%store-prefix))
(target (%store-prefix))
(writable? #f)))
;;; file-systems.scm ends here