71f15ca871
* gnu/build/file-systems.scm (read-bcachefs-superblock): Make comment less damned negative.
959 lines
36 KiB
Scheme
959 lines
36 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2020, 2021 Ludovic Courtès <ludo@gnu.org>
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;;; Copyright © 2016, 2017 David Craven <david@craven.ch>
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;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
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;;; Copyright © 2019 Guillaume Le Vaillant <glv@posteo.net>
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;;; Copyright © 2019–2021 Tobias Geerinckx-Rice <me@tobias.gr>
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;;; Copyright © 2019 David C. Trudgian <dave@trudgian.net>
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;;; Copyright © 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com>
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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 build file-systems)
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#:use-module (gnu system uuid)
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#:use-module (gnu system file-systems)
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#:use-module (guix build utils)
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#:use-module (guix build bournish)
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#:use-module ((guix build syscalls)
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#:hide (file-system-type))
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#:use-module (rnrs io ports)
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#:use-module (rnrs bytevectors)
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#:use-module (ice-9 match)
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#:use-module (ice-9 rdelim)
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#:use-module (system foreign)
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#:autoload (system repl repl) (start-repl)
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#:use-module (srfi srfi-1)
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#:use-module (srfi srfi-26)
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#:export (disk-partitions
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partition-label-predicate
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partition-uuid-predicate
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partition-luks-uuid-predicate
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find-partition-by-label
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find-partition-by-uuid
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find-partition-by-luks-uuid
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canonicalize-device-spec
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read-partition-label
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read-partition-uuid
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read-luks-partition-uuid
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bind-mount
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mount-flags->bit-mask
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check-file-system
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mount-file-system))
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;;; Commentary:
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;;;
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;;; This modules provides tools to deal with disk partitions, and to mount and
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;;; check file systems.
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;;;
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;;; Code:
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(define (bind-mount source target)
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"Bind-mount SOURCE at TARGET."
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(mount source target "" MS_BIND))
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(define (seek* fd/port offset whence)
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"Like 'seek' but return -1 instead of throwing to 'system-error' upon
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EINVAL. This makes it easier to catch cases like OFFSET being too large for
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FD/PORT."
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(catch 'system-error
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(lambda ()
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(seek fd/port offset whence))
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(lambda args
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(if (= EINVAL (system-error-errno args))
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-1
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(apply throw args)))))
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(define (read-superblock device offset size magic?)
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"Read a superblock of SIZE from OFFSET and DEVICE. Return the raw
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superblock on success, and #f if no valid superblock was found. MAGIC?
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takes a bytevector and returns #t when it's a valid superblock."
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(call-with-input-file device
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(lambda (port)
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(and (= offset (seek* port offset SEEK_SET))
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(let ((block (make-bytevector size)))
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(match (get-bytevector-n! port block 0 (bytevector-length block))
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((? eof-object?)
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#f)
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((? number? len)
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(and (= len (bytevector-length block))
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(and (magic? block)
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block)))))))))
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(define null-terminated-latin1->string
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(cut latin1->string <> zero?))
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(define (bytevector-utf16-length bv)
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"Given a bytevector BV containing a NUL-terminated UTF16-encoded string,
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determine where the NUL terminator is and return its index. If there's no
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NUL terminator, return the size of the bytevector."
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(let ((length (bytevector-length bv)))
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(let loop ((index 0))
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(if (< index length)
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(if (zero? (bytevector-u16-ref bv index 'little))
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index
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(loop (+ index 2)))
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length))))
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(define* (bytevector->u16-list bv endianness #:optional (index 0))
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(if (< index (bytevector-length bv))
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(cons (bytevector-u16-ref bv index endianness)
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(bytevector->u16-list bv endianness (+ index 2)))
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'()))
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;; The initrd doesn't have iconv data, so do the conversion ourselves.
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(define (utf16->string bv endianness)
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(list->string
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(map integer->char
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(reverse
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(let loop ((remainder (bytevector->u16-list bv endianness))
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(result '()))
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(match remainder
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(() result)
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((a) (cons a result))
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((a b x ...)
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(if (and (>= a #xD800) (< a #xDC00) ; high surrogate
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(>= b #xDC00) (< b #xE000)) ; low surrogate
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(loop x (cons (+ #x10000
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(* #x400 (- a #xD800))
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(- b #xDC00))
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result))
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(loop (cons b x) (cons a result))))))))))
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(define (null-terminated-utf16->string bv endianness)
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(utf16->string (sub-bytevector bv 0 (bytevector-utf16-length bv))
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endianness))
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;;;
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;;; Ext2 file systems.
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;;;
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;; <http://www.nongnu.org/ext2-doc/ext2.html#DEF-SUPERBLOCK>.
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;; TODO: Use "packed structs" from Guile-OpenGL or similar.
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(define-syntax %ext2-endianness
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;; Endianness of ext2 file systems.
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(identifier-syntax (endianness little)))
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(define (ext2-superblock? sblock)
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"Return #t when SBLOCK is an ext2 superblock."
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(let ((magic (bytevector-u16-ref sblock 56 %ext2-endianness)))
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(= magic #xef53)))
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(define (read-ext2-superblock device)
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"Return the raw contents of DEVICE's ext2 superblock as a bytevector, or #f
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if DEVICE does not contain an ext2 file system."
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(read-superblock device 1024 264 ext2-superblock?))
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(define (ext2-superblock-uuid sblock)
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"Return the UUID of ext2 superblock SBLOCK as a 16-byte bytevector."
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(sub-bytevector sblock 104 16))
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(define (ext2-superblock-volume-name sblock)
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"Return the volume name of SBLOCK as a string of at most 16 characters, or
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#f if SBLOCK has no volume name."
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(null-terminated-latin1->string (sub-bytevector sblock 120 16)))
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(define (check-ext2-file-system device)
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"Return the health of an ext2 file system on DEVICE."
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(match (status:exit-val
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(system* "e2fsck" "-v" "-p" "-C" "0" device))
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(0 'pass)
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(1 'errors-corrected)
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(2 'reboot-required)
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(_ 'fatal-error)))
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;;;
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;;; Linux swap.
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;;;
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;; Linux "swap space" is not a file system but it has a UUID and volume name,
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;; like actual file systems, and we want to be able to look up swap partitions
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;; by UUID and by label.
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(define %linux-swap-magic
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(string->utf8 "SWAPSPACE2"))
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;; Like 'PAGE_SIZE' in Linux, arch/x86/include/asm/page.h.
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;; XXX: This is always 4K on x86_64, i386, and ARMv7. However, on AArch64,
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;; this is determined by 'CONFIG_ARM64_PAGE_SHIFT' in the kernel, which is 12
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;; by default (4K) but can be 14 or 16.
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(define %page-size 4096)
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(define (linux-swap-superblock? sblock)
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"Return #t when SBLOCK is an linux-swap superblock."
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(and (= (bytevector-length sblock) %page-size)
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(bytevector=? (sub-bytevector sblock (- %page-size 10) 10)
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%linux-swap-magic)))
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(define (read-linux-swap-superblock device)
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"Return the raw contents of DEVICE's linux-swap superblock as a bytevector, or #f
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if DEVICE does not contain an linux-swap file system."
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(read-superblock device 0 %page-size linux-swap-superblock?))
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;; See 'union swap_header' in 'include/linux/swap.h'.
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(define (linux-swap-superblock-uuid sblock)
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"Return the UUID of Linux-swap superblock SBLOCK as a 16-byte bytevector."
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(sub-bytevector sblock (+ 1024 4 4 4) 16))
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(define (linux-swap-superblock-volume-name sblock)
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"Return the label of Linux-swap superblock SBLOCK as a string."
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(null-terminated-latin1->string
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(sub-bytevector sblock (+ 1024 4 4 4 16) 16)))
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;;;
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;;; Bcachefs file systems.
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;;;
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;; <https://evilpiepirate.org/git/bcachefs-tools.git/tree/libbcachefs/bcachefs_format.h>
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(define-syntax %bcachefs-endianness
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;; Endianness of bcachefs file systems.
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(identifier-syntax (endianness little)))
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(define (bcachefs-superblock? sblock)
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"Return #t when SBLOCK is an bcachefs superblock."
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(bytevector=? (sub-bytevector sblock 24 16)
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#vu8(#xc6 #x85 #x73 #xf6 #x4e #x1a #x45 #xca
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#x82 #x65 #xf5 #x7f #x48 #xba #x6d #x81)))
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(define (read-bcachefs-superblock device)
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"Return the raw contents of DEVICE's bcachefs superblock as a bytevector, or #f
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if DEVICE does not contain a bcachefs file system."
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;; Field offsets & lengths, in bytes. There are more (and the superblock is
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;; extensible) but we need only some basic information here:
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;; 0 16 bch_csum
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;; 16 8 version
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;; 24 16 magic
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;; 40 16 uuid ← ‘internal’: you probably don't want this one
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;; 56 16 user_uuid ← ‘external’: user-visible one by which to mount
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;; 72 32 label
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;; Assume a sane file system: ignore the back-up superblock & checksums.
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(read-superblock device 4096 104 bcachefs-superblock?))
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(define (bcachefs-superblock-external-uuid sblock)
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"Return the external UUID of bcachefs superblock SBLOCK as a 16-byte
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bytevector."
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(sub-bytevector sblock 56 16))
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(define (bcachefs-superblock-volume-name sblock)
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"Return the volume name of SBLOCK as a string of at most 32 characters, or
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#f if SBLOCK has no volume name."
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(null-terminated-latin1->string (sub-bytevector sblock 72 32)))
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(define (check-bcachefs-file-system device)
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"Return the health of a bcachefs file system on DEVICE."
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(let ((ignored-bits (logior 2)) ; DEVICE was mounted read-only
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(status
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;; A number, or #f on abnormal termination (e.g., assertion failure).
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(status:exit-val
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(apply system* "bcachefs" "fsck" "-p" "-v"
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;; Make each multi-device member a separate argument.
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(string-split device #\:)))))
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(match (and=> status (cut logand <> (lognot ignored-bits)))
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(0 'pass)
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(1 'errors-corrected)
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(_ 'fatal-error))))
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;;;
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;;; Btrfs file systems.
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;;;
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;; <https://btrfs.wiki.kernel.org/index.php/On-disk_Format#Superblock>.
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(define-syntax %btrfs-endianness
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;; Endianness of btrfs file systems.
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(identifier-syntax (endianness little)))
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(define (btrfs-superblock? sblock)
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"Return #t when SBLOCK is a btrfs superblock."
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(bytevector=? (sub-bytevector sblock 64 8)
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(string->utf8 "_BHRfS_M")))
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(define (read-btrfs-superblock device)
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"Return the raw contents of DEVICE's btrfs superblock as a bytevector, or #f
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if DEVICE does not contain a btrfs file system."
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(read-superblock device 65536 4096 btrfs-superblock?))
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(define (btrfs-superblock-uuid sblock)
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"Return the UUID of a btrfs superblock SBLOCK as a 16-byte bytevector."
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(sub-bytevector sblock 32 16))
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(define (btrfs-superblock-volume-name sblock)
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"Return the volume name of SBLOCK as a string of at most 256 characters, or
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#f if SBLOCK has no volume name."
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(null-terminated-latin1->string (sub-bytevector sblock 299 256)))
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(define (check-btrfs-file-system device)
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"Return the health of a btrfs file system on DEVICE."
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(match (status:exit-val
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(system* "btrfs" "device" "scan"))
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(0 'pass)
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(_ 'fatal-error)))
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;;;
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;;; FAT32 file systems.
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;;;
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;; <http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-107.pdf>.
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(define (fat32-superblock? sblock)
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"Return #t when SBLOCK is a fat32 superblock."
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(bytevector=? (sub-bytevector sblock 82 8)
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(string->utf8 "FAT32 ")))
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(define (read-fat32-superblock device)
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"Return the raw contents of DEVICE's fat32 superblock as a bytevector, or
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#f if DEVICE does not contain a fat32 file system."
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(read-superblock device 0 90 fat32-superblock?))
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(define (fat32-superblock-uuid sblock)
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"Return the Volume ID of a fat superblock SBLOCK as a 4-byte bytevector."
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(sub-bytevector sblock 67 4))
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(define (fat32-superblock-volume-name sblock)
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"Return the volume name of SBLOCK as a string of at most 11 characters, or
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#f if SBLOCK has no volume name. The volume name is a latin1 string.
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Trailing spaces are trimmed."
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(string-trim-right (latin1->string (sub-bytevector sblock 71 11) (lambda (c) #f)) #\space))
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(define (check-fat-file-system device)
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"Return the health of a fat file system on DEVICE."
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(match (status:exit-val
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(system* "fsck.vfat" "-v" "-a" device))
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(0 'pass)
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(1 'errors-corrected)
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(_ 'fatal-error)))
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;;;
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;;; FAT16 file systems.
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;;;
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(define (fat16-superblock? sblock)
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"Return #t when SBLOCK is a fat16 boot record."
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(bytevector=? (sub-bytevector sblock 54 8)
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(string->utf8 "FAT16 ")))
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(define (read-fat16-superblock device)
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"Return the raw contents of DEVICE's fat16 superblock as a bytevector, or
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#f if DEVICE does not contain a fat16 file system."
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(read-superblock device 0 62 fat16-superblock?))
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(define (fat16-superblock-uuid sblock)
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"Return the Volume ID of a fat superblock SBLOCK as a 4-byte bytevector."
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(sub-bytevector sblock 39 4))
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(define (fat16-superblock-volume-name sblock)
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"Return the volume name of SBLOCK as a string of at most 11 characters, or
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#f if SBLOCK has no volume name. The volume name is a latin1 string.
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Trailing spaces are trimmed."
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(string-trim-right (latin1->string (sub-bytevector sblock 43 11)
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(lambda (c) #f))
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#\space))
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;;;
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;;; ISO9660 file systems.
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;;;
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;; <http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-119.pdf>.
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(define (iso9660-superblock? sblock)
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"Return #t when SBLOCK is an iso9660 volume descriptor."
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(bytevector=? (sub-bytevector sblock 1 6)
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;; Note: "\x01" is the volume descriptor format version
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(string->utf8 "CD001\x01")))
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(define (read-iso9660-primary-volume-descriptor device offset)
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"Find and read the first primary volume descriptor, starting at OFFSET.
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Return #f if not found."
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(let* ((sblock (read-superblock device offset 2048 iso9660-superblock?))
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(type-code (if sblock
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(bytevector-u8-ref sblock 0)
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(error (format #f
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"Could not read ISO9660 primary
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volume descriptor from ~s"
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device)))))
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(match type-code
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(255 #f) ; Volume Descriptor Set Terminator.
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(1 sblock) ; Primary Volume Descriptor
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(_ (read-iso9660-primary-volume-descriptor device (+ offset 2048))))))
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(define (read-iso9660-superblock device)
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"Return the raw contents of DEVICE's iso9660 primary volume descriptor
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as a bytevector, or #f if DEVICE does not contain an iso9660 file system."
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;; Start reading at sector 16.
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;; Since we are not sure that the device contains an ISO9660 file system,
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;; we have to find that out first.
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(if (read-superblock device (* 2048 16) 2048 iso9660-superblock?)
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(read-iso9660-primary-volume-descriptor device (* 2048 16))
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#f)) ; Device does not contain an iso9660 file system.
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(define (iso9660-superblock-uuid sblock)
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"Return the modification time of an iso9660 primary volume descriptor
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SBLOCK as a bytevector. If that's not set, returns the creation time."
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;; Drops GMT offset for compatibility with Grub, blkid and /dev/disk/by-uuid.
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;; Compare Grub: "2014-12-02-19-30-23-00".
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;; Compare blkid result: "2014-12-02-19-30-23-00".
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;; Compare /dev/disk/by-uuid entry: "2014-12-02-19-30-23-00".
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(let* ((creation-time (sub-bytevector sblock 813 17))
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(modification-time (sub-bytevector sblock 830 17))
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(unset-time (make-bytevector 17 0))
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(time (if (bytevector=? unset-time modification-time)
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creation-time
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modification-time)))
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(sub-bytevector time 0 16))) ; strips GMT offset.
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(define (iso9660-superblock-volume-name sblock)
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"Return the volume name of SBLOCK as a string. The volume name is an ASCII
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string. Trailing spaces are trimmed."
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;; Note: Valid characters are of the set "[0-9][A-Z]_" (ECMA-119 Appendix A)
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(string-trim-right (latin1->string (sub-bytevector sblock 40 32)
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(lambda (c) #f)) #\space))
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;;;
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;;; JFS file systems.
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;;;
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;; Taken from <linux-libre>/fs/jfs/jfs_superblock.h.
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(define-syntax %jfs-endianness
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;; Endianness of JFS file systems.
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(identifier-syntax (endianness little)))
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(define (jfs-superblock? sblock)
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"Return #t when SBLOCK is a JFS superblock."
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(bytevector=? (sub-bytevector sblock 0 4)
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(string->utf8 "JFS1")))
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(define (read-jfs-superblock device)
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"Return the raw contents of DEVICE's JFS superblock as a bytevector, or #f
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||
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)))
|
||
|
||
|
||
;;;
|
||
;;; F2FS (Flash-Friendly File System)
|
||
;;;
|
||
|
||
;;; https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/tree/include/linux/f2fs_fs.h
|
||
;;; (but using xxd proved to be simpler)
|
||
|
||
(define-syntax %f2fs-endianness
|
||
;; Endianness of F2FS file systems
|
||
(identifier-syntax (endianness little)))
|
||
|
||
;; F2FS actually stores two adjacent copies of the superblock.
|
||
;; should we read both?
|
||
(define (f2fs-superblock? sblock)
|
||
"Return #t when SBLOCK is an F2FS superblock."
|
||
(let ((magic (bytevector-u32-ref sblock 0 %f2fs-endianness)))
|
||
(= magic #xF2F52010)))
|
||
|
||
(define (read-f2fs-superblock device)
|
||
"Return the raw contents of DEVICE's F2FS superblock as a bytevector, or #f
|
||
if DEVICE does not contain an F2FS file system."
|
||
(read-superblock device
|
||
;; offset of magic in first copy
|
||
#x400
|
||
;; difference between magic of second
|
||
;; and first copies
|
||
(- #x1400 #x400)
|
||
f2fs-superblock?))
|
||
|
||
(define (f2fs-superblock-uuid sblock)
|
||
"Return the UUID of F2FS superblock SBLOCK as a 16-byte bytevector."
|
||
(sub-bytevector sblock
|
||
(- (+ #x460 12)
|
||
;; subtract superblock offset
|
||
#x400)
|
||
16))
|
||
|
||
(define (f2fs-superblock-volume-name sblock)
|
||
"Return the volume name of SBLOCK as a string of at most 512 characters, or
|
||
#f if SBLOCK has no volume name."
|
||
(null-terminated-utf16->string
|
||
(sub-bytevector sblock (- (+ #x470 12) #x400) 512)
|
||
%f2fs-endianness))
|
||
|
||
(define (check-f2fs-file-system device)
|
||
"Return the health of a F2FS file system on DEVICE."
|
||
(match (status:exit-val
|
||
(system* "fsck.f2fs" "-p" device))
|
||
;; 0 and -1 are the only two possibilities
|
||
;; (according to the manpage)
|
||
(0 'pass)
|
||
(_ '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.
|
||
|
||
;; The LUKS2 header format is described in "LUKS2 On-Disk Format Specification":
|
||
;; <https://gitlab.com/cryptsetup/LUKS2-docs/blob/master/luks2_doc_wip.pdf>.
|
||
;; It is a WIP 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)
|
||
(or (= version 1) (= version 2)))))
|
||
|
||
(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 binary header, which includes key slots in
|
||
;; LUKS1. In LUKS2 the binary header is partially backward compatible, so
|
||
;; that UUID can be extracted as for LUKS1. Keyslots and other metadata are
|
||
;; not part of this header in LUKS2, but are included in the JSON metadata
|
||
;; area that follows.
|
||
(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))))
|
||
|
||
|
||
;;;
|
||
;;; NTFS file systems.
|
||
;;;
|
||
|
||
;; Taken from <linux-libre>/fs/ntfs/layout.h
|
||
|
||
(define-syntax %ntfs-endianness
|
||
;; Endianness of NTFS file systems.
|
||
(identifier-syntax (endianness little)))
|
||
|
||
(define (ntfs-superblock? sblock)
|
||
"Return #t when SBLOCK is a NTFS superblock."
|
||
(bytevector=? (sub-bytevector sblock 3 8)
|
||
(string->utf8 "NTFS ")))
|
||
|
||
(define (read-ntfs-superblock device)
|
||
"Return the raw contents of DEVICE's NTFS superblock as a bytevector, or #f
|
||
if DEVICE does not contain a NTFS file system."
|
||
(read-superblock device 0 511 ntfs-superblock?))
|
||
|
||
(define (ntfs-superblock-uuid sblock)
|
||
"Return the UUID of NTFS superblock SBLOCK as a 8-byte bytevector."
|
||
(sub-bytevector sblock 72 8))
|
||
|
||
;; TODO: Add ntfs-superblock-volume-name. The partition label is not stored
|
||
;; in the BOOT SECTOR like the UUID, but in the MASTER FILE TABLE, which seems
|
||
;; way harder to access.
|
||
|
||
(define (check-ntfs-file-system device)
|
||
"Return the health of a NTFS file system on DEVICE."
|
||
(match (status:exit-val
|
||
(system* "ntfsfix" device))
|
||
(0 'pass)
|
||
(_ 'fatal-error)))
|
||
|
||
|
||
;;;
|
||
;;; 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, EIO, and ENOMEDIUM errors are
|
||
caught and lead to a warning and #f as the result."
|
||
(lambda (device)
|
||
(catch 'system-error
|
||
(lambda ()
|
||
(proc device))
|
||
(lambda args
|
||
(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."
|
||
(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-linux-swap-superblock
|
||
linux-swap-superblock-volume-name)
|
||
(partition-field-reader read-bcachefs-superblock
|
||
bcachefs-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)
|
||
(partition-field-reader read-f2fs-superblock
|
||
f2fs-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-linux-swap-superblock
|
||
linux-swap-superblock-uuid)
|
||
(partition-field-reader read-bcachefs-superblock
|
||
bcachefs-superblock-external-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)
|
||
(partition-field-reader read-f2fs-superblock
|
||
f2fs-superblock-uuid)
|
||
(partition-field-reader read-ntfs-superblock
|
||
ntfs-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."
|
||
;; When running on the hand-made /dev, 'disk-partitions' could return
|
||
;; partitions for which we have no /dev node. Handle that gracefully.
|
||
(let ((reader (ENOENT-safe reader)))
|
||
(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 or an nfs-root
|
||
containing ':/')."
|
||
(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?)
|
||
(if (string-contains spec ":/")
|
||
spec ; do not resolve NFS devices
|
||
;; 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? "bcachefs" type) check-bcachefs-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)
|
||
((string-prefix? "f2fs" type) check-f2fs-file-system)
|
||
((string-prefix? "ntfs" type) check-ntfs-file-system)
|
||
((string-prefix? "nfs" type) (const 'pass))
|
||
(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))
|
||
(source (canonicalize-device-spec (file-system-device fs)))
|
||
(target (string-append root "/"
|
||
(file-system-mount-point fs)))
|
||
(flags (logior (mount-flags->bit-mask (file-system-flags fs))
|
||
|
||
;; For bind mounts, preserve the original flags such
|
||
;; as MS_NOSUID, etc. Failing to do that, the
|
||
;; MS_REMOUNT call below fails with EPERM.
|
||
;; See <https://bugs.gnu.org/46292>
|
||
(if (memq 'bind-mount (file-system-flags fs))
|
||
(statfs-flags->mount-flags
|
||
(file-system-mount-flags (statfs source)))
|
||
0)))
|
||
(options (file-system-options fs)))
|
||
(when (file-system-check? fs)
|
||
(check-file-system source type))
|
||
|
||
(catch 'system-error
|
||
(lambda ()
|
||
;; 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? target)
|
||
(mkdir-p (dirname target))
|
||
(call-with-output-file target (const #t)))
|
||
(mkdir-p target))
|
||
|
||
(cond
|
||
((string-prefix? "nfs" type)
|
||
(mount-nfs source target type flags options))
|
||
(else
|
||
(mount source target 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_REMOUNT flags)))
|
||
(mount source target type flags options))))
|
||
(lambda args
|
||
(or (file-system-mount-may-fail? fs)
|
||
(apply throw args))))))
|
||
|
||
;;; file-systems.scm ends here
|