432 lines
14 KiB
Scheme
432 lines
14 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
|
||
;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2018 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 (rnrs bytevectors)
|
||
#:use-module (srfi srfi-1)
|
||
#:use-module (guix records)
|
||
#:use-module (gnu system uuid)
|
||
#:re-export (uuid ;backward compatibility
|
||
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-location
|
||
|
||
file-system-type-predicate
|
||
|
||
file-system->spec
|
||
spec->file-system
|
||
specification->file-system-mapping
|
||
|
||
%pseudo-file-system-types
|
||
%fuse-control-file-system
|
||
%binary-format-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))
|
||
|
||
;;; 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:
|
||
|
||
;; 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>
|
||
(location file-system-location
|
||
(default (current-source-location))
|
||
(innate)))
|
||
|
||
;; 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."
|
||
(cond ((resolve-module '(guix store) #:ensure #f)
|
||
=>
|
||
(lambda (store)
|
||
((module-ref store '%store-prefix))))
|
||
((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,
|
||
where both FILE1 and FILE2 are absolute file name. For example:
|
||
|
||
(file-prefix? \"/gnu\" \"/gnu/store\")
|
||
=> #t
|
||
|
||
(file-prefix? \"/gn\" \"/gnu/store\")
|
||
=> #f
|
||
"
|
||
(and (string-prefix? "/" file1)
|
||
(string-prefix? "/" 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)))))))
|
||
|
||
(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 title mount-point type flags options _ _ check?)
|
||
(list (if (uuid? device)
|
||
`(uuid ,(uuid-type device) ,(uuid-bytevector device))
|
||
device)
|
||
title mount-point type flags options check?))))
|
||
|
||
(define (spec->file-system sexp)
|
||
"Deserialize SEXP, a list, to the corresponding <file-system> object."
|
||
(match sexp
|
||
((device title mount-point type flags options check?)
|
||
(file-system
|
||
(device (match device
|
||
(('uuid (? symbol? type) (? bytevector? bv))
|
||
(bytevector->uuid bv type))
|
||
(_
|
||
device)))
|
||
(title title)
|
||
(mount-point mount-point) (type type)
|
||
(flags flags) (options options)
|
||
(check? check?)))))
|
||
|
||
(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" "devpts" "devtmpfs" "fusectl"
|
||
"proc" "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 %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")))))
|
||
|
||
(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
|
||
%shared-memory-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)))
|
||
|
||
;;; file-systems.scm ends here
|