checkservices

#!/bin/bash

# Copyright © Sébastien Luttringer
#
# This program 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 2
# of the License, or (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

# Check running systemd services for binary update
# Convenient way to restart updated systemd service after upgrade

# disable grep options to avoid non default behaviour
unset GREP_OPTIONS

# Systemd cgroup path
SYSTEMD_CGROUP_BASE_PATH='/sys/fs/cgroup/systemd'

# colors
if [[ -t 1 ]]; then
	shopt -s xpg_echo
	c_arrow='\e[1;34m'
	c_title='\e[1;37m'
	c_svc='\e[1;35m'
	c_warn='\e[5;30;43m'
	c_error='\e[1;31m'
	c_rst='\e[m'
fi

# default options
confirm=1			# confirm before restart
dbus=1				# relauch when dbus
debug=0				# debug mode
failed=1			# display failed service at the end
pacdiff=1			# run pacdiff
reload=1			# reload systemd
restart=1			# restart services
serialize=0			# run in parallel
status=1			# display status after systemctl
user_slice=0		# act on users services

# display application usage and exit 2
usage() {
	echo "usage ${0##*/} [options]"
	echo "description: check for updated files in a service"
	echo 'options:'
	echo '  -h: this help' >&2
	echo "  -d: debug mode" >&2
	echo "  -b/-B: restart (or not) ${0##*/} if dbus was updated (default: $dbus)" >&2
	echo "  -c/-C: ask (or not) confirmation before restart" >&2
	echo "  -l/-L: call (or not) systemd daemon-reload (default: $reload)" >&2
	echo "  -f/-F: display (or not) failed services before quit (default: $failed)" >&2
	echo "  -p/-P: call (or not) pacdiff before act (default: $pacdiff)" >&2
	echo "  -r/-R: restart (or not) services with updated files (default: $restart)" >&2
	echo "  -s/-S: display (or not) status of restarted service (default: $status)" >&2
	echo "  -u/-U: act (or not) on services in users slice (default: $user_slice)" >&2
	echo "  -z/-Z: serialize (or not) action (default: $serialize)" >&2
	exit 2
}

# print $* as an arrow line
arrow() {
	printf "%b==> %b%s%b\n" "$c_arrow" "$c_title" "$*" "$c_rst"
}

# print $* as an error message
error() {
	printf "%bError: %b%s%b\n" "$c_error" "$c_title" "$*" "$c_rst" >&2
}

# usage : in_array( $needle, $haystack )
# return : 0 - found
#          1 - not found
in_array() {
	local needle=$1; shift
	local item
	for item in "$@"; do
	   [[ $item = $needle ]] && return 0 # Found
	done
	return 1 # Not Found
}

# ask for confirmation before restarting services
confirm_restart() {
	if (( $confirm == 1 )); then
		while true; do
			printf 'Confirm services restart? [y|N] '
			read -r ans || return 1
			case $ans in
				y|Y|yes|Yes) return 0;;
				n|N|no|No) return 1;;
			esac
		done
	else
		return 0
	fi
}

while getopts 'hBbCcdFfLlPpRrSsUuZz' opt; do
	case $opt in
		B) dbus=0;;				b) dbus=1;;
		C) confirm=0;;			c) confirm=1;;
		d) debug=1;;
		F) failed=0;;			f) failed=1;;
		L) reload=0;;			l) reload=1;;
		P) pacdiff=0;;			p) pacdiff=1;;
		R) restart=0;;			r) restart=1;;
		S) status=0;;			s) status=1;;
		U) user_slice=0;;		u) user_slice=1;;
		Z) serialize=0;;		z) serialize=1;;
		*) usage;;
	esac
done
shift $((OPTIND - 1));
(( $# > 0 )) && usage

# avoid to be sighup'ed by interactive shell
trap '' SIGHUP

# from now, we need to be root
(( $UID != 0 )) && error 'You need to be root' && exit 1

# call pacdiff
(( $pacdiff )) && arrow 'Run pacdiff' && pacdiff

# reload units list
(( $reload )) && arrow 'Reload systemd' && systemctl --system daemon-reload

# list of running services
arrow 'List runnings systemd services'
declare -a services
services=($(systemctl --no-legend --full --type service --state running|cut -f1 -d' '))

# list of bus names
arrow 'List Dbus clients'
declare -a buses
buses=($(dbus-send --system --dest=org.freedesktop.DBus --type=method_call \--print-reply \
/org/freedesktop/DBus org.freedesktop.DBus.ListNames|sed -rn 's/\s*string "(.*)"/\1/p'))

# count beggar services
arrow "Search for updated mapped files"
declare -a needy=() pids=()
declare -i pid=0
for svc in "${services[@]}"; do
	unit_path="$(systemctl -p ControlGroup show "$svc"|cut -f 2 -d=)"
	busname="$(systemctl -p BusName show "$svc"|cut -f 2 -d=)"
	# get the right pidfile name
	unset pidfile
	for path in "$SYSTEMD_CGROUP_BASE_PATH$unit_path/cgroup.procs" \
		"$SYSTEMD_CGROUP_BASE_PATH$unit_path/tasks"; do
		[[ -r "$path" ]] && pidfile="$path" && continue
	done
	[[ -z "$pidfile" ]] && error "Unable to find pid file for $svc." && continue
	# skip non system units
	(( $user_slice == 0 )) && [[ "$unit_path" =~ /user\.slice/ ]] && continue
	# parse pidfile
	pids=( $(< "$pidfile") )
	if (( "${#pids[*]}" == 0 )); then
		error "Unable to parse pid file for $svc."
		continue
	fi
	for pid in "${pids[@]}"; do
		maps_path="/proc/$pid/maps"
		[[ -r "$maps_path" ]] || {
			error "Unable to read maps file of $svc for pid $pid."
			continue
		}
		deleted=$(grep -F '(deleted)' "$maps_path" |sed -nr 's|^\S+ ..x. \S+ \S+ \S+ \s+||p'|sort|uniq)
		if [[ -n $deleted ]] || { [[ -n "$busname" ]] && ! in_array "$busname" "${buses[@]}"; }; then
			needy+=("$svc")
			if (( $debug )); then
				echo "${c_title}Service:${c_svc} $svc${c_rst}"
				echo "${c_title}Pid:${c_rst} $pid"
				echo "${c_title}Bus:${c_rst} $busname"
				echo -n "${c_title}BusName matching on the system bus: ${c_rst}"
				in_array "$busname" "${buses[@]}" && echo 'Yes' || echo 'No'
				echo "${c_title}Deleted files:${c_rst}"
				echo "$deleted"
				echo
			fi
			break
		fi
	done
done

# display what we will do
(( "${#needy[*]}" )) && echo '-------8<-------------------------------8<---------'
for svc in "${needy[@]}"; do
	echo "systemctl restart '$svc'"
done
(( "${#needy[*]}" )) && echo '-------8<-------------------------------8<---------'

# start the dangerous action below
if (( $restart == 1 && ${#needy[*]} > 0 )) && confirm_restart; then

	declare -A registered_pids=()
	declare -a running_pids=()
	declare -i last_registered_pids_count

	# do the job, restart updated services
	for svc in "${needy[@]}"; do
		echo "Restarting ${c_svc}$svc${c_rst}"
		systemctl restart "$svc" &
		if (( $serialize )); then
			wait
			# display status directly when serialize and not quiet
			(( $status )) && systemctl --no-pager --lines=0 status "$svc"
		else
			# register pids
			registered_pids[$!]="$svc"
		fi
	done

	# display status as soon as available when not serialized
	while (( ${#registered_pids[*]} )); do
		# wait for process at least one process to finish
		wait -n

		running_pids=( $(jobs -p) )

		# count registered pid for loop protection
		last_registered_pids_count=${#registered_pids[*]}

		for pid in "${!registered_pids[@]}"; do
			in_array "$pid" "${running_pids[@]}" && continue
			# show units status
			(( $status )) && systemctl --no-pager --lines=0 status "${registered_pids[$pid]}"
			unset registered_pids[$pid]
			break
		done

		# ensure we are not at 1st infinite loop
		# if we didn't remove a process something wrong happen
		if (( $last_registered_pids_count == ${#registered_pids[*]} )); then
			error "Unable to wait processes to finish"
			error "Registered PIDs: ${registered_pids[*]}"
			error "Running PIDs: ${running_pids[*]}"
			break
		fi
	done

	# warn if dbus was restart
	if in_array dbus.service "${needy[@]}"; then
		echo "${c_warn}After dbus restart, you should run ${0##*/} twice${c_rst}" >&2
		if (( $dbus )) && [[ -z "$CHECKSERVICE_WAS_RESTARTED" ]]; then
			echo "${c_warn}Doing it for you. No need to thanks me!${c_rst}" >&2
			export CHECKSERVICE_WAS_RESTARTED=1
			exec "$0" "$@"
		fi
	fi
fi

(( $failed )) && arrow "List failed units" && systemctl --failed --all --no-pager --no-legend --full list-units

exit 0