zfs/etc/systemd/system-generators/zfs-mount-generator.in

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#!/bin/sh
# zfs-mount-generator - generates systemd mount units for zfs
# Copyright (c) 2017 Antonio Russo <antonio.e.russo@gmail.com>
# Copyright (c) 2020 InsanePrawn <insane.prawny@gmail.com>
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
set -e
FSLIST="@sysconfdir@/zfs/zfs-list.cache"
[ -d "${FSLIST}" ] || exit 0
do_fail() {
printf 'zfs-mount-generator: %s\n' "$*" > /dev/kmsg
exit 1
}
# test if $1 is in space-separated list $2
is_known() {
query="$1"
IFS=' '
# protect against special characters
set -f
for element in $2 ; do
if [ "$query" = "$element" ] ; then
return 0
fi
done
return 1
}
# create dependency on unit file $1
# of type $2, i.e. "wants" or "requires"
# in the target units from space-separated list $3
create_dependencies() {
unitfile="$1"
suffix="$2"
# protect against special characters
set -f
for target in $3 ; do
target_dir="${dest_norm}/${target}.${suffix}/"
mkdir -p "${target_dir}"
ln -s "../${unitfile}" "${target_dir}"
done
}
# see systemd.generator
if [ $# -eq 0 ] ; then
dest_norm="/tmp"
elif [ $# -eq 3 ] ; then
dest_norm="${1}"
else
do_fail "zero or three arguments required"
fi
# All needed information about each ZFS is available from
# zfs list -H -t filesystem -o <properties>
# cached in $FSLIST, and each line is processed by the following function:
# See the list below for the properties and their order
process_line() {
# zfs list -H -o name,...
# fields are tab separated
IFS="$(printf '\t')"
# protect against special characters in, e.g., mountpoints
set -f
# shellcheck disable=SC2086
set -- $1
dataset="${1}"
p_mountpoint="${2}"
p_canmount="${3}"
p_atime="${4}"
p_relatime="${5}"
p_devices="${6}"
p_exec="${7}"
p_readonly="${8}"
p_setuid="${9}"
p_nbmand="${10}"
p_encroot="${11}"
p_keyloc="${12}"
p_systemd_requires="${13}"
p_systemd_requiresmountsfor="${14}"
p_systemd_before="${15}"
p_systemd_after="${16}"
p_systemd_wantedby="${17}"
p_systemd_requiredby="${18}"
p_systemd_nofail="${19}"
p_systemd_ignore="${20}"
# Minimal pre-requisites to mount a ZFS dataset
# By ordering before zfs-mount.service, we avoid race conditions.
after="zfs-import.target"
before="zfs-mount.service"
wants="zfs-import.target"
requires=""
requiredmounts=""
wantedby=""
requiredby=""
noauto="off"
if [ -n "${p_systemd_after}" ] && \
[ "${p_systemd_after}" != "-" ] ; then
after="${p_systemd_after} ${after}"
fi
if [ -n "${p_systemd_before}" ] && \
[ "${p_systemd_before}" != "-" ] ; then
before="${p_systemd_before} ${before}"
fi
if [ -n "${p_systemd_requires}" ] && \
[ "${p_systemd_requires}" != "-" ] ; then
requires="Requires=${p_systemd_requires}"
fi
if [ -n "${p_systemd_requiresmountsfor}" ] && \
[ "${p_systemd_requiresmountsfor}" != "-" ] ; then
requiredmounts="RequiresMountsFor=${p_systemd_requiresmountsfor}"
fi
# Handle encryption
if [ -n "${p_encroot}" ] &&
[ "${p_encroot}" != "-" ] ; then
keyloadunit="zfs-load-key-$(systemd-escape "${p_encroot}").service"
if [ "${p_encroot}" = "${dataset}" ] ; then
keymountdep=""
if [ "${p_keyloc%%://*}" = "file" ] ; then
if [ -n "${requiredmounts}" ] ; then
keymountdep="${requiredmounts} '${p_keyloc#file://}'"
else
keymountdep="RequiresMountsFor='${p_keyloc#file://}'"
fi
keyloadscript="@sbindir@/zfs load-key \"${dataset}\""
elif [ "${p_keyloc}" = "prompt" ] ; then
keyloadscript="\
count=0;\
while [ \$\$count -lt 3 ];do\
systemd-ask-password --id=\"zfs:${dataset}\"\
\"Enter passphrase for ${dataset}:\"|\
@sbindir@/zfs load-key \"${dataset}\" && exit 0;\
count=\$\$((count + 1));\
done;\
exit 1"
else
printf 'zfs-mount-generator: (%s) invalid keylocation\n' \
"${dataset}" >/dev/kmsg
fi
keyloadcmd="\
/bin/sh -c '\
set -eu;\
keystatus=\"\$\$(@sbindir@/zfs get -H -o value keystatus \"${dataset}\")\";\
[ \"\$\$keystatus\" = \"unavailable\" ] || exit 0;\
${keyloadscript}'"
# Generate the key-load .service unit
#
# Note: It is tempting to use a `<<EOF` style here-document for this, but
# bash requires a writable /tmp or $TMPDIR for that. This is not always
# available early during boot.
#
echo \
"# Automatically generated by zfs-mount-generator
[Unit]
Description=Load ZFS key for ${dataset}
SourcePath=${cachefile}
Documentation=man:zfs-mount-generator(8)
DefaultDependencies=no
Wants=${wants}
After=${after}
${requires}
${keymountdep}
[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=${keyloadcmd}
ExecStop=@sbindir@/zfs unload-key '${dataset}'" > "${dest_norm}/${keyloadunit}"
fi
# Update the dependencies for the mount file to want the
# key-loading unit.
wants="${wants} ${keyloadunit}"
after="${after} ${keyloadunit}"
fi
# Prepare the .mount unit
# skip generation of the mount unit if org.openzfs.systemd:ignore is "on"
if [ -n "${p_systemd_ignore}" ] ; then
if [ "${p_systemd_ignore}" = "on" ] ; then
return
elif [ "${p_systemd_ignore}" = "-" ] \
|| [ "${p_systemd_ignore}" = "off" ] ; then
: # This is OK
else
do_fail "invalid org.openzfs.systemd:ignore for ${dataset}"
fi
fi
# Check for canmount=off .
if [ "${p_canmount}" = "off" ] ; then
return
elif [ "${p_canmount}" = "noauto" ] ; then
noauto="on"
elif [ "${p_canmount}" = "on" ] ; then
: # This is OK
else
do_fail "invalid canmount for ${dataset}"
fi
# Check for legacy and blank mountpoints.
if [ "${p_mountpoint}" = "legacy" ] ; then
return
elif [ "${p_mountpoint}" = "none" ] ; then
return
elif [ "${p_mountpoint%"${p_mountpoint#?}"}" != "/" ] ; then
do_fail "invalid mountpoint for ${dataset}"
fi
# Escape the mountpoint per systemd policy.
mountfile="$(systemd-escape --path --suffix=mount "${p_mountpoint}")"
# Parse options
# see lib/libzfs/libzfs_mount.c:zfs_add_options
opts=""
# atime
if [ "${p_atime}" = on ] ; then
# relatime
if [ "${p_relatime}" = on ] ; then
opts="${opts},atime,relatime"
elif [ "${p_relatime}" = off ] ; then
opts="${opts},atime,strictatime"
else
printf 'zfs-mount-generator: (%s) invalid relatime\n' \
"${dataset}" >/dev/kmsg
fi
elif [ "${p_atime}" = off ] ; then
opts="${opts},noatime"
else
printf 'zfs-mount-generator: (%s) invalid atime\n' \
"${dataset}" >/dev/kmsg
fi
# devices
if [ "${p_devices}" = on ] ; then
opts="${opts},dev"
elif [ "${p_devices}" = off ] ; then
opts="${opts},nodev"
else
printf 'zfs-mount-generator: (%s) invalid devices\n' \
"${dataset}" >/dev/kmsg
fi
# exec
if [ "${p_exec}" = on ] ; then
opts="${opts},exec"
elif [ "${p_exec}" = off ] ; then
opts="${opts},noexec"
else
printf 'zfs-mount-generator: (%s) invalid exec\n' \
"${dataset}" >/dev/kmsg
fi
# readonly
if [ "${p_readonly}" = on ] ; then
opts="${opts},ro"
elif [ "${p_readonly}" = off ] ; then
opts="${opts},rw"
else
printf 'zfs-mount-generator: (%s) invalid readonly\n' \
"${dataset}" >/dev/kmsg
fi
# setuid
if [ "${p_setuid}" = on ] ; then
opts="${opts},suid"
elif [ "${p_setuid}" = off ] ; then
opts="${opts},nosuid"
else
printf 'zfs-mount-generator: (%s) invalid setuid\n' \
"${dataset}" >/dev/kmsg
fi
# nbmand
if [ "${p_nbmand}" = on ] ; then
opts="${opts},mand"
elif [ "${p_nbmand}" = off ] ; then
opts="${opts},nomand"
else
printf 'zfs-mount-generator: (%s) invalid nbmand\n' \
"${dataset}" >/dev/kmsg
fi
if [ -n "${p_systemd_wantedby}" ] && \
[ "${p_systemd_wantedby}" != "-" ] ; then
noauto="on"
if [ "${p_systemd_wantedby}" = "none" ] ; then
wantedby=""
else
wantedby="${p_systemd_wantedby}"
before="${before} ${wantedby}"
fi
fi
if [ -n "${p_systemd_requiredby}" ] && \
[ "${p_systemd_requiredby}" != "-" ] ; then
noauto="on"
if [ "${p_systemd_requiredby}" = "none" ] ; then
requiredby=""
else
requiredby="${p_systemd_requiredby}"
before="${before} ${requiredby}"
fi
fi
# For datasets with canmount=on, a dependency is created for
# local-fs.target by default. To avoid regressions, this dependency
# is reduced to "wants" rather than "requires" when nofail is not "off".
# **THIS MAY CHANGE**
# noauto=on disables this behavior completely.
if [ "${noauto}" != "on" ] ; then
if [ "${p_systemd_nofail}" = "off" ] ; then
requiredby="local-fs.target"
before="${before} local-fs.target"
else
wantedby="local-fs.target"
if [ "${p_systemd_nofail}" != "on" ] ; then
before="${before} local-fs.target"
fi
fi
fi
# Handle existing files:
# 1. We never overwrite existing files, although we may delete
# files if we're sure they were created by us. (see 5.)
# 2. We handle files differently based on canmount. Units with canmount=on
# always have precedence over noauto. This is enforced by the sort pipe
# in the loop around this function.
# It is important to use $p_canmount and not $noauto here, since we
# sort by canmount while other properties also modify $noauto, e.g.
# org.openzfs.systemd:wanted-by.
# 3. If no unit file exists for a noauto dataset, we create one.
# Additionally, we use $noauto_files to track the unit file names
# (which are the systemd-escaped mountpoints) of all (exclusively)
# noauto datasets that had a file created.
# 4. If the file to be created is found in the tracking variable,
# we do NOT create it.
# 5. If a file exists for a noauto dataset, we check whether the file
# name is in the variable. If it is, we have multiple noauto datasets
# for the same mountpoint. In such cases, we remove the file for safety.
# To avoid further noauto datasets creating a file for this path again,
# we leave the file name in the tracking variable.
if [ -e "${dest_norm}/${mountfile}" ] ; then
if is_known "$mountfile" "$noauto_files" ; then
# if it's in $noauto_files, we must be noauto too. See 2.
printf 'zfs-mount-generator: removing duplicate noauto %s\n' \
"${mountfile}" >/dev/kmsg
# See 5.
rm "${dest_norm}/${mountfile}"
else
# don't log for canmount=noauto
if [ "${p_canmount}" = "on" ] ; then
printf 'zfs-mount-generator: %s already exists. Skipping.\n' \
"${mountfile}" >/dev/kmsg
fi
fi
# file exists; Skip current dataset.
return
else
if is_known "${mountfile}" "${noauto_files}" ; then
# See 4.
return
elif [ "${p_canmount}" = "noauto" ] ; then
noauto_files="${mountfile} ${noauto_files}"
fi
fi
# Create the .mount unit file.
#
# (Do not use `<<EOF`-style here-documents for this, see warning above)
#
echo \
"# Automatically generated by zfs-mount-generator
[Unit]
SourcePath=${cachefile}
Documentation=man:zfs-mount-generator(8)
Before=${before}
After=${after}
Wants=${wants}
${requires}
${requiredmounts}
[Mount]
Where=${p_mountpoint}
What=${dataset}
Type=zfs
Options=defaults${opts},zfsutil" > "${dest_norm}/${mountfile}"
# Finally, create the appropriate dependencies
create_dependencies "${mountfile}" "wants" "$wantedby"
create_dependencies "${mountfile}" "requires" "$requiredby"
}
for cachefile in "${FSLIST}/"* ; do
# Sort cachefile's lines by canmount, "on" before "noauto"
# and feed each line into process_line
sort -t "$(printf '\t')" -k 3 -r "${cachefile}" | \
( # subshell is necessary for `sort|while read` and $noauto_files
noauto_files=""
while read -r fs ; do
process_line "${fs}"
done
)
done