TakeV/guix
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
guix/gnu/build/file-systems.scm
Tobias Geerinckx-Rice 1abbe7c64b
file-systems: Add support for JFS. 
* gnu/build/file-systems.scm (%jfs-endianness): New syntax.
(jfs-superblock?, read-jfs-superblock, jfs-superblock-uuid)
(jfs-superblock-volume-name, check-jfs-file-system): New procedures.
(%partition-label-readers, %partition-uuid-readers, check-file-system):
Register them.
2020-01-03 13:54:13 +01:00

687 lines
25 KiB
Scheme
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2016, 2017 David Craven <david@craven.ch>
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;; Copyright © 2019 Guillaume Le Vaillant <glv@posteo.net>
;;; Copyright © 2019 Tobias Geerinckx-Rice <me@tobias.gr>
;;;
;;; 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 build file-systems)
#:use-module (gnu system uuid)
#:use-module (gnu system file-systems)
#:use-module (guix build utils)
#:use-module (guix build bournish)
#:use-module ((guix build syscalls)
#:hide (file-system-type))
#:use-module (rnrs io ports)
#:use-module (rnrs bytevectors)
#:use-module (ice-9 match)
#:use-module (ice-9 rdelim)
#:use-module (system foreign)
#:autoload (system repl repl) (start-repl)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:export (disk-partitions
partition-label-predicate
partition-uuid-predicate
partition-luks-uuid-predicate
find-partition-by-label
find-partition-by-uuid
find-partition-by-luks-uuid
canonicalize-device-spec
read-partition-label
read-partition-uuid
read-luks-partition-uuid
bind-mount
mount-flags->bit-mask
check-file-system
mount-file-system))
;;; Commentary:
;;;
;;; This modules provides tools to deal with disk partitions, and to mount and
;;; check file systems.
;;;
;;; Code:
(define (bind-mount source target)
"Bind-mount SOURCE at TARGET."
(mount source target "" MS_BIND))
(define (seek* fd/port offset whence)
"Like 'seek' but return -1 instead of throwing to 'system-error' upon
EINVAL. This makes it easier to catch cases like OFFSET being too large for
FD/PORT."
(catch 'system-error
(lambda ()
(seek fd/port offset whence))
(lambda args
(if (= EINVAL (system-error-errno args))
-1
(apply throw args)))))
(define (read-superblock device offset size magic?)
"Read a superblock of SIZE from OFFSET and DEVICE. Return the raw
superblock on success, and #f if no valid superblock was found. MAGIC?
takes a bytevector and returns #t when it's a valid superblock."
(call-with-input-file device
(lambda (port)
(and (= offset (seek* port offset SEEK_SET))
(let ((block (make-bytevector size)))
(match (get-bytevector-n! port block 0 (bytevector-length block))
((? eof-object?)
#f)
((? number? len)
(and (= len (bytevector-length block))
(and (magic? block)
block)))))))))
(define null-terminated-latin1->string
(cut latin1->string <> zero?))
;;;
;;; Ext2 file systems.
;;;
;; <http://www.nongnu.org/ext2-doc/ext2.html#DEF-SUPERBLOCK>.
;; TODO: Use "packed structs" from Guile-OpenGL or similar.
(define-syntax %ext2-endianness
;; Endianness of ext2 file systems.
(identifier-syntax (endianness little)))
(define (ext2-superblock? sblock)
"Return #t when SBLOCK is an ext2 superblock."
(let ((magic (bytevector-u16-ref sblock 56 %ext2-endianness)))
(= magic #xef53)))
(define (read-ext2-superblock device)
"Return the raw contents of DEVICE's ext2 superblock as a bytevector, or #f
if DEVICE does not contain an ext2 file system."
(read-superblock device 1024 264 ext2-superblock?))
(define (ext2-superblock-uuid sblock)
"Return the UUID of ext2 superblock SBLOCK as a 16-byte bytevector."
(sub-bytevector sblock 104 16))
(define (ext2-superblock-volume-name sblock)
"Return the volume name of SBLOCK as a string of at most 16 characters, or
#f if SBLOCK has no volume name."
(null-terminated-latin1->string (sub-bytevector sblock 120 16)))
(define (check-ext2-file-system device)
"Return the health of an ext2 file system on DEVICE."
(match (status:exit-val
(system* "e2fsck" "-v" "-p" "-C" "0" device))
(0 'pass)
(1 'errors-corrected)
(2 'reboot-required)
(_ 'fatal-error)))
;;;
;;; Btrfs file systems.
;;;
;; <https://btrfs.wiki.kernel.org/index.php/On-disk_Format#Superblock>.
(define-syntax %btrfs-endianness
;; Endianness of btrfs file systems.
(identifier-syntax (endianness little)))
(define (btrfs-superblock? sblock)
"Return #t when SBLOCK is a btrfs superblock."
(bytevector=? (sub-bytevector sblock 64 8)
(string->utf8 "_BHRfS_M")))
(define (read-btrfs-superblock device)
"Return the raw contents of DEVICE's btrfs superblock as a bytevector, or #f
if DEVICE does not contain a btrfs file system."
(read-superblock device 65536 4096 btrfs-superblock?))
(define (btrfs-superblock-uuid sblock)
"Return the UUID of a btrfs superblock SBLOCK as a 16-byte bytevector."
(sub-bytevector sblock 32 16))
(define (btrfs-superblock-volume-name sblock)
"Return the volume name of SBLOCK as a string of at most 256 characters, or
#f if SBLOCK has no volume name."
(null-terminated-latin1->string (sub-bytevector sblock 299 256)))
(define (check-btrfs-file-system device)
"Return the health of a btrfs file system on DEVICE."
(match (status:exit-val
(system* "btrfs" "device" "scan"))
(0 'pass)
(_ 'fatal-error)))
;;;
;;; FAT32 file systems.
;;;
;; <http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-107.pdf>.
(define (fat32-superblock? sblock)
"Return #t when SBLOCK is a fat32 superblock."
(bytevector=? (sub-bytevector sblock 82 8)
(string->utf8 "FAT32 ")))
(define (read-fat32-superblock device)
"Return the raw contents of DEVICE's fat32 superblock as a bytevector, or
#f if DEVICE does not contain a fat32 file system."
(read-superblock device 0 90 fat32-superblock?))
(define (fat32-superblock-uuid sblock)
"Return the Volume ID of a fat superblock SBLOCK as a 4-byte bytevector."
(sub-bytevector sblock 67 4))
(define (fat32-superblock-volume-name sblock)
"Return the volume name of SBLOCK as a string of at most 11 characters, or
#f if SBLOCK has no volume name. The volume name is a latin1 string.
Trailing spaces are trimmed."
(string-trim-right (latin1->string (sub-bytevector sblock 71 11) (lambda (c) #f)) #\space))
(define (check-fat-file-system device)
"Return the health of a fat file system on DEVICE."
(match (status:exit-val
(system* "fsck.vfat" "-v" "-a" device))
(0 'pass)
(1 'errors-corrected)
(_ 'fatal-error)))
;;;
;;; FAT16 file systems.
;;;
(define (fat16-superblock? sblock)
"Return #t when SBLOCK is a fat16 boot record."
(bytevector=? (sub-bytevector sblock 54 8)
(string->utf8 "FAT16 ")))
(define (read-fat16-superblock device)
"Return the raw contents of DEVICE's fat16 superblock as a bytevector, or
#f if DEVICE does not contain a fat16 file system."
(read-superblock device 0 62 fat16-superblock?))
(define (fat16-superblock-uuid sblock)
"Return the Volume ID of a fat superblock SBLOCK as a 4-byte bytevector."
(sub-bytevector sblock 39 4))
(define (fat16-superblock-volume-name sblock)
"Return the volume name of SBLOCK as a string of at most 11 characters, or
#f if SBLOCK has no volume name. The volume name is a latin1 string.
Trailing spaces are trimmed."
(string-trim-right (latin1->string (sub-bytevector sblock 43 11)
(lambda (c) #f))
#\space))
;;;
;;; ISO9660 file systems.
;;;
;; <http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-119.pdf>.
(define (iso9660-superblock? sblock)
"Return #t when SBLOCK is an iso9660 volume descriptor."
(bytevector=? (sub-bytevector sblock 1 6)
;; Note: "\x01" is the volume descriptor format version
(string->utf8 "CD001\x01")))
(define (read-iso9660-primary-volume-descriptor device offset)
"Find and read the first primary volume descriptor, starting at OFFSET.
Return #f if not found."
(let* ((sblock (read-superblock device offset 2048 iso9660-superblock?))
(type-code (if sblock
(bytevector-u8-ref sblock 0)
(error (format #f
"Could not read ISO9660 primary
volume descriptor from ~s"
device)))))
(match type-code
(255 #f) ; Volume Descriptor Set Terminator.
(1 sblock) ; Primary Volume Descriptor
(_ (read-iso9660-primary-volume-descriptor device (+ offset 2048))))))
(define (read-iso9660-superblock device)
"Return the raw contents of DEVICE's iso9660 primary volume descriptor
as a bytevector, or #f if DEVICE does not contain an iso9660 file system."
;; Start reading at sector 16.
;; Since we are not sure that the device contains an ISO9660 file system,
;; we have to find that out first.
(if (read-superblock device (* 2048 16) 2048 iso9660-superblock?)
(read-iso9660-primary-volume-descriptor device (* 2048 16))
#f)) ; Device does not contain an iso9660 file system.
(define (iso9660-superblock-uuid sblock)
"Return the modification time of an iso9660 primary volume descriptor
SBLOCK as a bytevector. If that's not set, returns the creation time."
;; Drops GMT offset for compatibility with Grub, blkid and /dev/disk/by-uuid.
;; Compare Grub: "2014-12-02-19-30-23-00".
;; Compare blkid result: "2014-12-02-19-30-23-00".
;; Compare /dev/disk/by-uuid entry: "2014-12-02-19-30-23-00".
(let* ((creation-time (sub-bytevector sblock 813 17))
(modification-time (sub-bytevector sblock 830 17))
(unset-time (make-bytevector 17 0))
(time (if (bytevector=? unset-time modification-time)
creation-time
modification-time)))
(sub-bytevector time 0 16))) ; strips GMT offset.
(define (iso9660-superblock-volume-name sblock)
"Return the volume name of SBLOCK as a string. The volume name is an ASCII
string. Trailing spaces are trimmed."
;; Note: Valid characters are of the set "[0-9][A-Z]_" (ECMA-119 Appendix A)
(string-trim-right (latin1->string (sub-bytevector sblock 40 32)
(lambda (c) #f)) #\space))
;;;
;;; JFS file systems.
;;;
;; Taken from <linux-libre>/fs/jfs/jfs_superblock.h.
(define-syntax %jfs-endianness
;; Endianness of JFS file systems.
(identifier-syntax (endianness little)))
(define (jfs-superblock? sblock)
"Return #t when SBLOCK is a JFS superblock."
(bytevector=? (sub-bytevector sblock 0 4)
(string->utf8 "JFS1")))
(define (read-jfs-superblock device)
"Return the raw contents of DEVICE's JFS superblock as a bytevector, or #f
if DEVICE does not contain a JFS file system."
(read-superblock device 32768 184 jfs-superblock?))
(define (jfs-superblock-uuid sblock)
"Return the UUID of JFS superblock SBLOCK as a 16-byte bytevector."
(sub-bytevector sblock 136 16))
(define (jfs-superblock-volume-name sblock)
"Return the volume name of SBLOCK as a string of at most 16 characters, or
#f if SBLOCK has no volume name."
(null-terminated-latin1->string (sub-bytevector sblock 152 16)))
(define (check-jfs-file-system device)
"Return the health of a JFS file system on DEVICE."
(match (status:exit-val
(system* "jfs_fsck" "-p" "-v" device))
(0 'pass)
(1 'errors-corrected)
(2 'reboot-required)
(_ 'fatal-error)))
;;;
;;; LUKS encrypted devices.
;;;
;; The LUKS header format is described in "LUKS On-Disk Format Specification":
;; <https://gitlab.com/cryptsetup/cryptsetup/wikis/Specification>. We follow
;; version 1.2.1 of this document.
(define-syntax %luks-endianness
;; Endianness of LUKS headers.
(identifier-syntax (endianness big)))
(define (luks-superblock? sblock)
"Return #t when SBLOCK is a luks superblock."
(define %luks-magic
;; The 'LUKS_MAGIC' constant.
(u8-list->bytevector (append (map char->integer (string->list "LUKS"))
(list #xba #xbe))))
(let ((magic (sub-bytevector sblock 0 6))
(version (bytevector-u16-ref sblock 6 %luks-endianness)))
(and (bytevector=? magic %luks-magic)
(= version 1))))
(define (read-luks-header file)
"Read a LUKS header from FILE. Return the raw header on success, and #f if
not valid header was found."
;; Size in bytes of the LUKS header, including key slots.
(read-superblock file 0 592 luks-superblock?))
(define (luks-header-uuid header)
"Return the LUKS UUID from HEADER, as a 16-byte bytevector."
;; 40 bytes are reserved for the UUID, but in practice, it contains the 36
;; bytes of its ASCII representation.
(let ((uuid (sub-bytevector header 168 36)))
(string->uuid (utf8->string uuid))))
;;;
;;; Partition lookup.
;;;
(define (disk-partitions)
"Return the list of device names corresponding to valid disk partitions."
(define (partition? name major minor)
;; grub-mkrescue does some funny things for EFI support which
;; makes it a lot more difficult than one would expect to support
;; booting an ISO-9660 image from an USB flash drive.
;; For example there's a buggy (too small) hidden partition in it
;; which Linux mounts and then proceeds to fail while trying to
;; fall off the edge.
;; In any case, partition tables are supposed to be optional so
;; here we allow checking entire disks for file systems, too.
(> major 2)) ;ignore RAM disks and floppy disks
(call-with-input-file "/proc/partitions"
(lambda (port)
;; Skip the two header lines.
(read-line port)
(read-line port)
;; Read each subsequent line, and extract the last space-separated
;; field.
(let loop ((parts '()))
(let ((line (read-line port)))
(if (eof-object? line)
(reverse parts)
(match (string-tokenize line)
(((= string->number major) (= string->number minor)
blocks name)
(if (partition? name major minor)
(loop (cons name parts))
(loop parts))))))))))
(define (ENOENT-safe proc)
"Wrap the one-argument PROC such that ENOENT errors are caught and lead to a
warning and #f as the result."
(lambda (device)
(catch 'system-error
(lambda ()
(proc device))
(lambda args
;; When running on the hand-made /dev,
;; 'disk-partitions' could return partitions for which
;; we have no /dev node. Handle that gracefully.
(let ((errno (system-error-errno args)))
(cond ((= ENOENT errno)
(format (current-error-port)
"warning: device '~a' not found~%" device)
#f)
((= ENOMEDIUM errno) ;for removable media
#f)
((= EIO errno) ;unreadable hardware like audio CDs
(format (current-error-port)
"warning: failed to read from device '~a'~%" device)
#f)
(else
(apply throw args))))))))
(define (partition-field-reader read field)
"Return a procedure that takes a device and returns the value of a FIELD in
the partition superblock or #f."
(let ((read (ENOENT-safe read)))
(lambda (device)
(let ((sblock (read device)))
(and sblock
(field sblock))))))
(define (read-partition-field device partition-field-readers)
"Returns the value of a FIELD in the partition superblock of DEVICE or #f. It
takes a list of PARTITION-FIELD-READERS and returns the result of the first
partition field reader that returned a value."
(match (filter-map (cut apply <> (list device)) partition-field-readers)
((field . _) field)
(_ #f)))
(define %partition-label-readers
(list (partition-field-reader read-iso9660-superblock
iso9660-superblock-volume-name)
(partition-field-reader read-ext2-superblock
ext2-superblock-volume-name)
(partition-field-reader read-btrfs-superblock
btrfs-superblock-volume-name)
(partition-field-reader read-fat32-superblock
fat32-superblock-volume-name)
(partition-field-reader read-fat16-superblock
fat16-superblock-volume-name)
(partition-field-reader read-jfs-superblock
jfs-superblock-volume-name)))
(define %partition-uuid-readers
(list (partition-field-reader read-iso9660-superblock
iso9660-superblock-uuid)
(partition-field-reader read-ext2-superblock
ext2-superblock-uuid)
(partition-field-reader read-btrfs-superblock
btrfs-superblock-uuid)
(partition-field-reader read-fat32-superblock
fat32-superblock-uuid)
(partition-field-reader read-fat16-superblock
fat16-superblock-uuid)
(partition-field-reader read-jfs-superblock
jfs-superblock-uuid)))
(define read-partition-label
(cut read-partition-field <> %partition-label-readers))
(define read-partition-uuid
(cut read-partition-field <> %partition-uuid-readers))
(define luks-partition-field-reader
(partition-field-reader read-luks-header luks-header-uuid))
(define read-luks-partition-uuid
(cut read-partition-field <> (list luks-partition-field-reader)))
(define (partition-predicate reader =)
"Return a predicate that returns true if the FIELD of partition header that
was READ is = to the given value."
(lambda (expected)
(lambda (device)
(let ((actual (reader device)))
(and actual
(= actual expected))))))
(define partition-label-predicate
(partition-predicate read-partition-label string=?))
(define partition-uuid-predicate
(partition-predicate read-partition-uuid uuid=?))
(define luks-partition-uuid-predicate
(partition-predicate luks-partition-field-reader uuid=?))
(define (find-partition predicate)
"Return the first partition found that matches PREDICATE, or #f if none
were found."
(lambda (expected)
(find (predicate expected)
(map (cut string-append "/dev/" <>)
(disk-partitions)))))
(define find-partition-by-label
(find-partition partition-label-predicate))
(define find-partition-by-uuid
(find-partition partition-uuid-predicate))
(define find-partition-by-luks-uuid
(find-partition luks-partition-uuid-predicate))
(define (canonicalize-device-spec spec)
"Return the device name corresponding to SPEC, which can be a <uuid>, a
<file-system-label>, or a string (typically a /dev file name)."
(define max-trials
;; Number of times we retry partition label resolution, 1 second per
;; trial. Note: somebody reported a delay of 16 seconds (!) before their
;; USB key would be detected by the kernel, so we must wait for at least
;; this long.
20)
(define (resolve find-partition spec fmt)
(let loop ((count 0))
(let ((device (find-partition spec)))
(or device
;; Some devices take a bit of time to appear, most notably USB
;; storage devices. Thus, wait for the device to appear.
(if (> count max-trials)
(error "failed to resolve partition" (fmt spec))
(begin
(format #t "waiting for partition '~a' to appear...~%"
(fmt spec))
(sleep 1)
(loop (+ 1 count))))))))
(match spec
((? string?)
;; Nothing to do, but wait until SPEC shows up.
(resolve identity spec identity))
((? file-system-label?)
;; Resolve the label.
(resolve find-partition-by-label
(file-system-label->string spec)
identity))
((? uuid?)
(resolve find-partition-by-uuid
(uuid-bytevector spec)
uuid->string))))
(define (check-file-system device type)
"Run a file system check of TYPE on DEVICE."
(define check-procedure
(cond
((string-prefix? "ext" type) check-ext2-file-system)
((string-prefix? "btrfs" type) check-btrfs-file-system)
((string-suffix? "fat" type) check-fat-file-system)
((string-prefix? "jfs" type) check-jfs-file-system)
(else #f)))
(if check-procedure
(match (check-procedure device)
('pass
#t)
('errors-corrected
(format (current-error-port)
"File system check corrected errors on ~a; continuing~%"
device))
('reboot-required
(format (current-error-port)
"File system check corrected errors on ~a; rebooting~%"
device)
(sleep 3)
(reboot))
('fatal-error
(format (current-error-port) "File system check on ~a failed~%"
device)
;; Spawn a REPL only if someone would be able to interact with it.
(when (isatty? (current-input-port))
(format (current-error-port) "Spawning Bourne-like REPL.~%")
;; 'current-output-port' is typically connected to /dev/klog (in
;; PID 1), but here we want to make sure we talk directly to the
;; user.
(with-output-to-file "/dev/console"
(lambda ()
(start-repl %bournish-language))))))
(format (current-error-port)
"No file system check procedure for ~a; skipping~%"
device)))
(define (mount-flags->bit-mask flags)
"Return the number suitable for the 'flags' argument of 'mount' that
corresponds to the symbols listed in FLAGS."
(let loop ((flags flags))
(match flags
(('read-only rest ...)
(logior MS_RDONLY (loop rest)))
(('bind-mount rest ...)
(logior MS_BIND (loop rest)))
(('no-suid rest ...)
(logior MS_NOSUID (loop rest)))
(('no-dev rest ...)
(logior MS_NODEV (loop rest)))
(('no-exec rest ...)
(logior MS_NOEXEC (loop rest)))
(('no-atime rest ...)
(logior MS_NOATIME (loop rest)))
(('strict-atime rest ...)
(logior MS_STRICTATIME (loop rest)))
(('lazy-time rest ...)
(logior MS_LAZYTIME (loop rest)))
(()
0))))
(define* (mount-file-system fs #:key (root "/root"))
"Mount the file system described by FS, a <file-system> object, under ROOT."
(define (mount-nfs source mount-point type flags options)
(let* ((idx (string-rindex source #\:))
(host-part (string-take source idx))
;; Strip [] from around host if present
(host (match (string-split host-part (string->char-set "[]"))
(("" h "") h)
((h) h)))
(aa (match (getaddrinfo host "nfs") ((x . _) x)))
(sa (addrinfo:addr aa))
(inet-addr (inet-ntop (sockaddr:fam sa)
(sockaddr:addr sa))))
;; Mounting an NFS file system requires passing the address
;; of the server in the addr= option
(mount source mount-point type flags
(string-append "addr="
inet-addr
(if options
(string-append "," options)
"")))))
(let ((type (file-system-type fs))
(options (file-system-options fs))
(source (canonicalize-device-spec (file-system-device fs)))
(mount-point (string-append root "/"
(file-system-mount-point fs)))
(flags (mount-flags->bit-mask (file-system-flags fs))))
(when (file-system-check? fs)
(check-file-system source type))
;; Create the mount point. Most of the time this is a directory, but
;; in the case of a bind mount, a regular file or socket may be needed.
(if (and (= MS_BIND (logand flags MS_BIND))
(not (file-is-directory? source)))
(unless (file-exists? mount-point)
(mkdir-p (dirname mount-point))
(call-with-output-file mount-point (const #t)))
(mkdir-p mount-point))
(cond
((string-prefix? "nfs" type)
(mount-nfs source mount-point type flags options))
(else
(mount source mount-point type flags options)))
;; For read-only bind mounts, an extra remount is needed, as per
;; <http://lwn.net/Articles/281157/>, which still applies to Linux 4.0.
(when (and (= MS_BIND (logand flags MS_BIND))
(= MS_RDONLY (logand flags MS_RDONLY)))
(let ((flags (logior MS_BIND MS_REMOUNT MS_RDONLY)))
(mount source mount-point type flags #f)))))
;;; file-systems.scm ends here
Reference in a new issue View git blame Copy permalink