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Add grub-btrfs
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@raoulh
raoulh committed Jul 30, 2023
1 parent 58b5394 commit 87b6c23
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340 changes: 340 additions & 0 deletions grub-btrfs/grub-btrfsd
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#!/usr/bin/env bash
# Copyright 2023 Pascal Jaeger
# Distributed under the terms of the GNU General Public License v3
# Update GRUB when new BTRFS snapshots are created.

sighandler() {
trap '""' SIGINT SIGTERM
vlog "Parent $$: Received signal SIGINT/ SIGTERM"
kill 0
wait
exit 0
}

setcolors() {
if [ "${1}" = true ]; then
GREEN=$'\033[0;32m'
RED=$'\033[0;31m'
CYAN=$'\033[;36m'
RESET=$'\033[0m'
fi
if [ "${1}" = false ]; then
GREEN=$'\033[0;0m'
RED=$'\033[0;0m'
CYAN=$'\033[;0m'
RESET=$'\033[0m'
fi
}

print_help() {
echo "${CYAN}[?] Usage:"
echo "${0##*/} [-h, --help] [-c, --no-color] [-l, --log-file LOG_FILE] [-r, --recursive] [-s, --syslog] [-t, --timeshift-auto] [-v, --verbose] SNAPSHOTS_DIRS"
echo
echo "SNAPSHOTS_DIRS Snapshot directories to watch, without effect when --timeshift-auto"
echo
echo "Optional arguments:"
echo "-c, --no-color Disable colors in output"
echo "-l, --log-file Specify a logfile to write to"
echo "-r, --recursive Watch snapshots directory recursively"
echo "-s, --syslog Write to syslog"
echo "-o, --timeshift-old Look for snapshots in directory of Timeshift <v22.06 (requires --timeshift-auto)"
echo "-t, --timeshift-auto Automatically detect Timeshifts snapshot directory"
echo "-v, --verbose Let the log of the daemon be more verbose"
echo "-h, --help Display this message"
echo
echo "Version ${GRUB_BTRFS_VERSION}${RESET}"
}

log() {
echo "${2}"$1"${RESET}"
if [ ${syslog} = true ]; then
logger -p user.notice -t ${0##*/}"["$$"]" "$1"
fi
if [ ${#logfile} -gt 1 ]; then
echo "$(date) ${1}" >> "${logfile}"
fi
}

vlog() {
if [ ${verbose} = true ]; then
echo "${2}"$1"${RESET}"
if [ ${syslog} = true ]; then
logger -p user.notice -t ${0##*/} "$1"
fi
if [ ${#logfile} -gt 1 ]; then
echo "$(date) ${1}" >> "${logfile}"
fi
fi
}

err() {
echo "${2}"${1}"${RESET}" >&2
if [ ${syslog} = true ]; then
logger -p user.error -t ${0##*/} "$1"
fi
if [ ${#logfile} -gt 1 ]; then
echo "$(date) error: ${1}" >> "${logfile}"
fi
}

parse_arguments() {
while getopts :l:ctvrsh-: opt; do
case "$opt" in
-)
case "${OPTARG}" in
no-color)
setcolors false
;;
log-file)
logfile="${!OPTIND}"; OPTIND=$(( $OPTIND + 1 ))
;;
timeshift-auto)
timeshift_auto=true
;;
timeshift-old)
timeshift_old=true
;;
verbose)
verbose=true
;;
recursive)
recursive=true
;;
syslog)
syslog=true
;;
help)
print_help
exit 0
;;
*)
if [ "$OPTERR" = 1 ] && [ "${optspec:0:1}" != ":" ]; then
err "[!] Unknown option --${OPTARG}" "${RED}" >&2
echo
fi
print_help
exit 1
;;
esac;;
c)
setcolors false
;;
l)
logfile="${OPTARG}"
;;
t)
timeshift_auto=true
;;
o)
timeshift_old=true
;;
v)
verbose=true
;;
r)
recursive=true
;;
s)
syslog=true
;;
h)
print_help
exit 0
;;
*)
if [ "$OPTERR" = 1 ] || [ "${optspec:0:1}" = ":" ]; then
err "[!] Non-option argument: '-${OPTARG}'" "${RED}" >&2
echo
fi
print_help
exit 1
;;
esac
done
}

checks() {
# check if inotify exists, see issue #227
if ! command -v inotifywait >/dev/null 2>&1; then
err "[!] inotifywait was not found, exiting. Is inotify-tools installed?" "${RED}" >&2
exit 1
fi

if [ ${timeshift_auto} = false ] && [ ${timeshift_old} = true ]; then
err "[!] Flag --timeshift-old requires flag --timeshift-auto" "${RED}" >&2
exit 1
fi

if ! [ ${timeshift_auto} = true ]; then
for snapdir in "${snapdirs[@]}"
do
if ! [ -d ${snapdir} ]; then
err "[!] No directory found at ${snapdir}" "${RED}" >&2
err "[!] Please specify a valid snapshot directory" "${RED}" >&2
exit 1
fi
done
fi
}

setup() {
if [ ${#logfile} -gt 1 ]; then
touch "${logfile}"
echo "GRUB-BTRFSD log $(date)" >> "${logfile}"
fi

if [ ${verbose} = true ]; then
inotify_qiet_flag=""
else
inotify_qiet_flag=" -q -q "
fi

if [ ${recursive} = true ]; then
inotify_recursive_flag=" -r "
else
inotify_recursive_flag=""
fi

if [ ${timeshift_auto} = true ]; then
watchtime=15
[ -d /run/timeshift ] || mkdir /run/timeshift
else
watchtime=0
fi
}

create_grub_menu() {
# create the grub submenu of the whole grub menu, depending on wether the submenu already exists
# and gives feedback if it worked
if grep "snapshots-btrfs" "${GRUB_BTRFS_GRUB_DIRNAME:-/boot/grub}"/grub.cfg; then
if /etc/grub.d/41_snapshots-btrfs; then
log "Grub submenu recreated" "${GREEN}"
else
err "[!] Error during grub submenu creation (grub-btrfs error)" "${RED}"
fi
else
if ${GRUB_BTRFS_MKCONFIG:-grub-mkconfig} -o "${GRUB_BTRFS_GRUB_DIRNAME:-/boot/grub}"/grub.cfg; then
log "Grub menu recreated" "${GREEN}"
else
err "[!] Error during grub menu creation (grub/ grub-btrfs error)" "${RED}"
fi
fi
}

set_snapshot_dir() {
# old timeshift has it's snapshot dir in a different location
if [ "${timeshift_old}" = true ]; then
snapdir="/run/timeshift/backup/timeshift-btrfs/snapshots"
else
snapdir="/run/timeshift/${timeshift_pid}/backup/timeshift-btrfs/snapshots"
fi
}

daemon_function() {
trap 'vlog "$BASHPID: Received SIGINT/ SIGTERM"; exit 0' SIGINT SIGTERM
# start the actual daemon
snapdir=$1
vlog "Subdaemon function started, PID: $BASHPID" "${GREEN}"
vlog "${BASHPID}: Entering infinite while for $snapdir" "${GREEN}"
vlog "${BASHPID}: Snapshot dir watchtimeout: $watchtime"
while true; do
runs=false
if [ ${timeshift_auto} = true ] && ! [ "${timeshift_pid}" -gt 0 ] ; then
# watch the timeshift folder for a folder that is created when timeshift starts up
sleep 1 # for safety so the outer while is not going crazy
if [ "${timeshift_pid}" -eq -2 ]; then
log "${BASHPID}: detected timeshift shutdown"
fi
timeshift_pid=$(ps ax | awk '{sub(/.*\//, "", $5)} $5 ~ /timeshift/ {print $1}')
if [ "${#timeshift_pid}" -gt 0 ]; then
set_snapshot_dir
log "${BASHPID}: detected running Timeshift at daemon startup, PID is: $timeshift_pid"
vlog "${BASHPID}: new snapshots directory is $snapdir"
else
log "Watching /run/timeshift for timeshift to start"
inotifywait ${inotify_qiet_flag} -e create -e delete /run/timeshift && {
sleep 1
timeshift_pid=$(ps ax | awk '{sub(/.*\//, "", $5)} $5 ~ /timeshift/ {print $1}')
set_snapshot_dir
log "${BASHPID}: detected Timeshift startup, PID is: $timeshift_pid" "${CYAN}"
vlog "${BASHPID}: new snapshots directory is $snapdir" "${CYAN}"
(create_grub_menu) # create the grub menu once immidiatly in a forking process. Snapshots from commandline using timeshift --create need this
}
fi
runs=false
else
while [ -d "$snapdir" ]; do
# watch the actual snapshots folder for a new snapshot or a deletion of a snapshot
if [ ${runs} = false ] && [ ${verbose} = false ]; then
log "${BASHPID}: Watching $snapdir for new snapshots..." "${CYAN}"
else
vlog "${BASHPID}: Watching $snapdir for new snapshots..." "${CYAN}"
fi
runs=true
inotifywait ${inotify_qiet_flag} ${inotify_recursive_flag} -e create -e delete -e unmount -t "$watchtime" "$snapdir" && {
log "${BASHPID}: Detected snapshot creation/ deletion, recreating Grub menu" "${CYAN}"
sleep 5
create_grub_menu
}
sleep 1
done
timeshift_pid=-2
fi
if ! [ ${timeshift_auto} = true ] && ! [ -d "${snapdir}" ] ; then # in case someone deletes the snapshots folder (in snapper mode) to prevent the while loop from going wild
break
fi
done
}

main() {
# init
timeshift_pid=-1
watchtime=0
logfile=0
snapshots=-1
timeshift_auto=false
timeshift_old=false
verbose=false
syslog=false
recursive=false
trap sighandler SIGINT SIGTERM

setcolors true # normally we want colors

sysconfdir="/etc"
grub_btrfs_config="${sysconfdir}/default/grub-btrfs/config"
# source config file
[ -f "$grub_btrfs_config" ] && . "$grub_btrfs_config"
[ -f "${sysconfdir}/default/grub" ] && . "${sysconfdir}/default/grub"

parse_arguments "${@}"
shift $(( OPTIND - 1 ))
snapdirs=( "${@}" )

vlog "Arguments:"
vlog "Snapshot directories: ${snapdirs[*]}"
vlog "Timestift autodetection: $timeshift_auto"
vlog "Timeshift old: $timeshift_old"
vlog "Logfile: $logfile"
vlog "Recursive: $recursive"

checks
setup

log "grub-btrfsd starting up..." "${GREEN}"

if [ ${timeshift_auto} = true ] ; then
daemon_function "timeshift" &
else
# for all dirs that got passed to the script, start a new fork with that dir
for snapdir in "${snapdirs[@]}"
do
vlog "starting daemon watching $snapdir..."
daemon_function "${snapdir}" &
done
fi
wait # wait for forks to finish, kill child forks if SIGTERM is sent
exit 0
}

main "${@}"

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