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#!/bin/bash
shopt -s extglob
# generated from util-linux source: libmount/src/utils.c
declare -A pseudofs_types=([anon_inodefs]=1
[autofs]=1
[bdev]=1
[bpf]=1
[binfmt_misc]=1
[cgroup]=1
[cgroup2]=1
[configfs]=1
[cpuset]=1
[debugfs]=1
[devfs]=1
[devpts]=1
[devtmpfs]=1
[dlmfs]=1
[efivarfs]=1
[fuse.gvfs-fuse-daemon]=1
[fusectl]=1
[hugetlbfs]=1
[mqueue]=1
[nfsd]=1
[none]=1
[pipefs]=1
[proc]=1
[pstore]=1
[ramfs]=1
[rootfs]=1
[rpc_pipefs]=1
[securityfs]=1
[sockfs]=1
[spufs]=1
[sysfs]=1
[tmpfs]=1)
# generated from: pkgfile -vbr '/fsck\..+' | awk -F. '{ print $NF }' | sort
declare -A fsck_types=([cramfs]=1
[exfat]=1
[ext2]=1
[ext3]=1
[ext4]=1
[ext4dev]=1
[jfs]=1
[minix]=1
[msdos]=1
[reiserfs]=1
[vfat]=1
[xfs]=1)
out() { printf "$1 $2\n" "${@:3}"; }
error() { out "==> ERROR:" "$@"; } >&2
warning() { out "==> WARNING:" "$@"; } >&2
msg() { out "==>" "$@"; }
msg2() { out " ->" "$@";}
die() { error "$@"; exit 1; }
ignore_error() {
"$@" 2>/dev/null
return 0
}
in_array() {
local i
for i in "${@:2}"; do
[[ $1 = "$i" ]] && return 0
done
return 1
}
chroot_add_mount() {
mount "$@" && CHROOT_ACTIVE_MOUNTS=("$2" "${CHROOT_ACTIVE_MOUNTS[@]}")
}
chroot_maybe_add_mount() {
local cond=$1; shift
if eval "$cond"; then
chroot_add_mount "$@"
fi
}
chroot_setup() {
CHROOT_ACTIVE_MOUNTS=()
[[ $(trap -p EXIT) ]] && die '(BUG): attempting to overwrite existing EXIT trap'
trap 'chroot_teardown' EXIT
chroot_add_mount proc "$1/proc" -t proc -o nosuid,noexec,nodev &&
chroot_add_mount sys "$1/sys" -t sysfs -o nosuid,noexec,nodev,ro &&
ignore_error chroot_maybe_add_mount "[[ -d '$1/sys/firmware/efi/efivars' ]]" \
efivarfs "$1/sys/firmware/efi/efivars" -t efivarfs -o nosuid,noexec,nodev &&
chroot_add_mount udev "$1/dev" -t devtmpfs -o mode=0755,nosuid &&
chroot_add_mount devpts "$1/dev/pts" -t devpts -o mode=0620,gid=5,nosuid,noexec &&
chroot_add_mount shm "$1/dev/shm" -t tmpfs -o mode=1777,nosuid,nodev &&
chroot_add_mount /run "$1/run" --bind &&
chroot_add_mount tmp "$1/tmp" -t tmpfs -o mode=1777,strictatime,nodev,nosuid
}
chroot_teardown() {
if (( ${#CHROOT_ACTIVE_MOUNTS[@]} )); then
umount "${CHROOT_ACTIVE_MOUNTS[@]}"
fi
unset CHROOT_ACTIVE_MOUNTS
}
try_cast() (
_=$(( $1#$2 ))
) 2>/dev/null
valid_number_of_base() {
local base=$1 len=${#2} i=
for (( i = 0; i < len; i++ )); do
try_cast "$base" "${2:i:1}" || return 1
done
return 0
}
mangle() {
local i= chr= out=
local {a..f}= {A..F}=
for (( i = 0; i < ${#1}; i++ )); do
chr=${1:i:1}
case $chr in
[[:space:]\\])
printf -v chr '%03o' "'$chr"
out+=\\
;;
esac
out+=$chr
done
printf '%s' "$out"
}
unmangle() {
local i= chr= out= len=$(( ${#1} - 4 ))
local {a..f}= {A..F}=
for (( i = 0; i < len; i++ )); do
chr=${1:i:1}
case $chr in
\\)
if valid_number_of_base 8 "${1:i+1:3}" ||
valid_number_of_base 16 "${1:i+1:3}"; then
printf -v chr '%b' "${1:i:4}"
(( i += 3 ))
fi
;;
esac
out+=$chr
done
printf '%s' "$out${1:i}"
}
optstring_match_option() {
local candidate pat patterns
IFS=, read -ra patterns <<<"$1"
for pat in "${patterns[@]}"; do
if [[ $pat = *=* ]]; then
# "key=val" will only ever match "key=val"
candidate=$2
else
# "key" will match "key", but also "key=anyval"
candidate=${2%%=*}
fi
[[ $pat = "$candidate" ]] && return 0
done
return 1
}
optstring_remove_option() {
local o options_ remove=$2 IFS=,
read -ra options_ <<<"${!1}"
for o in "${!options_[@]}"; do
optstring_match_option "$remove" "${options_[o]}" && unset 'options_[o]'
done
declare -g "$1=${options_[*]}"
}
optstring_normalize() {
local o options_ norm IFS=,
read -ra options_ <<<"${!1}"
# remove empty fields
for o in "${options_[@]}"; do
[[ $o ]] && norm+=("$o")
done
# avoid empty strings, reset to "defaults"
declare -g "$1=${norm[*]:-defaults}"
}
optstring_append_option() {
if ! optstring_has_option "$1" "$2"; then
declare -g "$1=${!1},$2"
fi
optstring_normalize "$1"
}
optstring_prepend_option() {
local options_=$1
if ! optstring_has_option "$1" "$2"; then
declare -g "$1=$2,${!1}"
fi
optstring_normalize "$1"
}
optstring_get_option() {
local opts o
IFS=, read -ra opts <<<"${!1}"
for o in "${opts[@]}"; do
if optstring_match_option "$2" "$o"; then
declare -g "$o"
return 0
fi
done
return 1
}
optstring_has_option() {
local "${2%%=*}"
optstring_get_option "$1" "$2"
}
dm_name_for_devnode() {
read dm_name <"/sys/class/block/${1#/dev/}/dm/name"
if [[ $dm_name ]]; then
printf '/dev/mapper/%s' "$dm_name"
else
# don't leave the caller hanging, just print the original name
# along with the failure.
error 'Failed to resolve device mapper name for: %s' "$1"
fi
}
fstype_is_pseudofs() {
(( pseudofs_types["$1"] ))
}
fstype_has_fsck() {
(( fsck_types["$1"] ))
}
write_source() {
local src=$1 spec= label= uuid= comment=()
label=$(lsblk -rno LABEL "$1" 2>/dev/null)
uuid=$(lsblk -rno UUID "$1" 2>/dev/null)
# bind mounts do not have a UUID!
case $bytag in
'')
[[ $uuid ]] && comment=("UUID=$uuid")
[[ $label ]] && comment+=("LABEL=$(mangle "$label")")
;;
LABEL)
spec=$label
[[ $uuid ]] && comment=("$src" "UUID=$uuid")
;;
UUID)
spec=$uuid
comment=("$src")
[[ $label ]] && comment+=("LABEL=$(mangle "$label")")
;;
*)
[[ $uuid ]] && comment=("$1" "UUID=$uuid")
[[ $label ]] && comment+=("LABEL=$(mangle "$label")")
[[ $bytag ]] && spec=$(lsblk -rno "$bytag" "$1" 2>/dev/null)
;;
esac
[[ $comment ]] && printf '# %s\n' "${comment[*]}"
if [[ $spec ]]; then
printf '%-20s' "$bytag=$(mangle "$spec")"
else
printf '%-20s' "$(mangle "$src")"
fi
}
optstring_apply_quirks() {
local varname=$1 fstype=$2
# SELinux displays a 'seclabel' option in /proc/self/mountinfo. We can't know
# if the system we're generating the fstab for has any support for SELinux (as
# one might install Arch from a Fedora environment), so let's remove it.
optstring_remove_option "$varname" seclabel
# Prune 'relatime' option for any pseudofs. This seems to be a rampant
# default which the kernel often exports even if the underlying filesystem
# doesn't support it. Example: https://bugs.archlinux.org/task/54554.
if awk -v fstype="$fstype" '$1 == fstype { exit 1 }' /proc/filesystems; then
optstring_remove_option "$varname" relatime
fi
case $fstype in
f2fs)
# These are Kconfig options for f2fs. Kernels supporting the options will
# only provide the negative versions of these (e.g. noacl), and vice versa
# for kernels without support.
optstring_remove_option "$varname" noacl,acl,nouser_xattr,user_xattr
;;
vfat)
# Before Linux v3.8, "cp" is prepended to the value of the codepage.
if optstring_get_option "$varname" codepage && [[ $codepage = cp* ]]; then
optstring_remove_option "$varname" codepage
optstring_append_option "$varname" "codepage=${codepage#cp}"
fi
;;
esac
}
usage() {
cat <<EOF
usage: ${0##*/} [options] root
Options:
-f <filter> Restrict output to mountpoints matching the prefix FILTER
-L Use labels for source identifiers (shortcut for -t LABEL)
-p Exclude pseudofs mounts (default behavior)
-P Include pseudofs mounts
-t <tag> Use TAG for source identifiers (TAG should be one of: LABEL,
UUID, PARTLABEL, PARTUUID)
-U Use UUIDs for source identifiers (shortcut for -t UUID)
-h Print this help message
genfstab generates output suitable for addition to an fstab file based on the
devices mounted under the mountpoint specified by the given root.
EOF
}
if [[ -z $1 || $1 = @(-h|--help) ]]; then
usage
exit $(( $# ? 0 : 1 ))
fi
while getopts ':f:LPpt:U' flag; do
case $flag in
L)
bytag=LABEL
;;
U)
bytag=UUID
;;
f)
prefixfilter=$OPTARG
;;
P)
pseudofs=1
;;
p)
pseudofs=0
;;
t)
bytag=${OPTARG^^}
;;
:)
die '%s: option requires an argument -- '\''%s'\' "${0##*/}" "$OPTARG"
;;
?)
die '%s: invalid option -- '\''%s'\' "${0##*/}" "$OPTARG"
;;
esac
done
shift $(( OPTIND - 1 ))
(( $# )) || die "No root directory specified"
root=$(realpath -mL "$1"); shift
if ! mountpoint -q "$root"; then
die "$root is not a mountpoint"
fi
# handle block devices
findmnt -Recvruno SOURCE,TARGET,FSTYPE,OPTIONS,FSROOT "$root" |
while read -r src target fstype opts fsroot; do
if (( !pseudofs )) && fstype_is_pseudofs "$fstype"; then
continue
fi
[[ $target = "$prefixfilter"* ]] || continue
# default 5th and 6th columns
dump=0 pass=2
src=$(unmangle "$src")
target=$(unmangle "$target")
target=${target#$root}
if (( !foundroot )) && findmnt "$src" "$root" >/dev/null; then
# this is root. we can't possibly have more than one...
pass=1 foundroot=1
fi
# if there's no fsck tool available, then only pass=0 makes sense.
if ! fstype_has_fsck "$fstype"; then
pass=0
fi
if [[ $fsroot != / && $fstype != btrfs ]]; then
# it's a bind mount
src=$(findmnt -funcevo TARGET "$src")$fsroot
if [[ $src -ef $target ]]; then
# hrmm, this is weird. we're probably looking at a file or directory
# that was bound into a chroot from the host machine. Ignore it,
# because this won't actually be a valid mount. Worst case, the user
# just re-adds it.
continue
fi
fstype=none
opts+=,bind
pass=0
fi
# filesystem quirks
case $fstype in
fuseblk)
# well-behaved FUSE filesystems will report themselves as fuse.$fstype.
# this is probably NTFS-3g, but let's just make sure.
if ! newtype=$(lsblk -no FSTYPE "$src") || [[ -z $newtype ]]; then
# avoid blanking out fstype, leading to an invalid fstab
error 'Failed to derive real filesystem type for FUSE device on %s' "$target"
else
fstype=$newtype
fi
;;
esac
optstring_apply_quirks "opts" "$fstype"
# write one line
write_source "$src"
printf '\t%-10s' "/$(mangle "${target#/}")" "$fstype" "$opts"
printf '\t%s %s' "$dump" "$pass"
printf '\n\n'
done
# handle swaps devices
{
# ignore header
read
while read -r device type _ _ prio; do
options=defaults
if (( prio >= 0 )); then
options+=,pri=$prio
fi
# skip files marked deleted by the kernel
[[ $device = *'\040(deleted)' ]] && continue
if [[ $type = file ]]; then
printf '%-20s' "${device#${root%/}}"
elif [[ $device = /dev/dm-+([0-9]) ]]; then
# device mapper doesn't allow characters we need to worry
# about being mangled, and it does the escaping of dashes
# for us in sysfs.
write_source "$(dm_name_for_devnode "$device")"
else
write_source "$(unmangle "$device")"
fi
printf '\t%-10s\t%-10s\t%-10s\t0 0\n\n' 'none' 'swap' "$options"
done
} </proc/swaps
# vim: et ts=2 sw=2 ft=sh: