#!/bin/sh
#
# init.d script for the Gearman worker daemon of PNP4Nagios
#
# Based on an example script for NPCD of Javier Fernandez-Sanguino
# Copyright (c) 2007 Javier Fernandez-Sanguino <jfs@debian.org>
# Copyright (c) 2011 Sebastian Harl <tokkee@debian.org>
#
### BEGIN INIT INFO
# Provides:          pnp_gearman_worker
# Required-Start:    $network $local_fs $remote_fs
# Required-Stop:     $network $local_fs $remote_fs
# Should-Start:
# Should-Stop:
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: PNP4Nagios Gearman worker daemon
# Description:       Processing of Nagios' perf data in distributed setups
### END INIT INFO

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

DAEMON=/usr/lib/pnp4nagios/libexec/process_perfdata.pl
NAME=pnp_gearman_worker
DESC="PNP4Nagios Gearman worker daemon"

PIDFILE=/var/run/pnp4nagios/$NAME.pid

test -x $DAEMON || exit 0

. /lib/lsb/init-functions

# Default options, these can be overriden by the information
# at /etc/default/$NAME
DAEMON_OPTS=""
DIETIME=10
STARTTIME=2
USER=nagios

if [ -f /etc/default/pnp_gearman_worker ] ; then
	. /etc/default/pnp_gearman_worker
fi

if [ "x$RUN" != "xyes" ] ; then
	echo "$NAME has been disabled in /etc/default/pnp_gearman_worker."
	exit 0
fi

set -e

# Check if a given process pid's cmdline matches a given name
running_pid() {
	pid=$1
	name=$2
	[ -z "$pid" ] && return 1
	[ ! -d /proc/$pid ] &&  return 1
	cmd=`cat /proc/$pid/cmdline | tr "\000" "\n" | head -n 1 | cut -d : -f 1`
	# Is this the expected server
	[ "$cmd" != "$name" ] &&  return 1
	return 0
}

# Check if the process is running looking at /proc
# (works for all users)
running() {
	# No pidfile, probably no daemon present
	[ ! -f "$PIDFILE" ] && return 1
	pid=`cat $PIDFILE`
	running_pid "$pid" $DAEMON \
		|| running_pid "$pid" "/usr/bin/perl" || return 1
	return 0
}

# Start the process using the wrapper
start_server() {
	if ! perl -MGearman::Worker -e '1;' > /dev/null 2>&1 \
			|| ! perl -MMIME::Base64 -e '1;' > /dev/null 2>&1 \
			|| ! perl -MCrypt::Rijndael -e '1;' > /dev/null 2>&1; then
		echo "$NAME requires the Gearman::Worker, MIME::Base64 and" >&2
		echo "Crypt::Rijndael Perl modules. Make sure that the packages" >&2
		echo "perl, libgearman-client-perl and libcrypt-rijndael-perl" >&2
		echo "are installed." >&2
		exit 1
	fi

	if [ -d /var/run/pnp4nagios ]; then
		chmod 755 /var/run/pnp4nagios
		chown nagios.nagios /var/run/pnp4nagios
	else
		install -d -m 755 -o nagios -g nagios /var/run/pnp4nagios
	fi

	start_opts="--start --quiet --oknodo --pidfile $PIDFILE"
	if [ -n "$USER" ]; then
		start_opts="$start_opts --chuid $USER"
	fi
	start-stop-daemon $start_opts --exec $DAEMON -- \
		--pidfile=$PIDFILE --gearman --daemon $DAEMON_OPTS
	errcode=$?
	return $errcode
}

# Stop the process using the wrapper
stop_server() {
	killproc -p $PIDFILE $DAEMON
	errcode=$?
	return $errcode
}

# Force the process to die killing it manually
force_stop() {
	[ ! -e "$PIDFILE" ] && return
	if running ; then
		kill -15 $pid
		# Is it really dead?
		sleep "$DIETIME"s
		if running ; then
			kill -9 $pid
			sleep "$DIETIME"s
			if running ; then
				echo "Cannot kill $NAME (pid=$pid)!"
				exit 1
			fi
		fi
	fi
	rm -f $PIDFILE
}

case "$1" in
	start)
		log_daemon_msg "Starting $DESC" "$NAME"
		# Check if it's running first
		if running ;  then
			log_progress_msg "apparently already running"
			log_end_msg 0
			exit 0
		fi
		if start_server ; then
			# NOTE: Some servers might die some time after they start,
			# this code will detect this issue if STARTTIME is set
			# to a reasonable value
			[ -n "$STARTTIME" ] && sleep $STARTTIME # Wait some time 
			if  running ;  then
				# It's ok, the server started and is running
				log_end_msg 0
			else
				# It is not running after we did start
				log_end_msg 1
			fi
		else
			# Either we could not start it
			log_end_msg 1
		fi
		;;
	stop)
		log_daemon_msg "Stopping $DESC" "$NAME"
		if running ; then
			# Only stop the server if we see it running
			errcode=0
			stop_server || errcode=$?
			log_end_msg $errcode
		else
			# If it's not running don't do anything
			log_progress_msg "apparently not running"
			log_end_msg 0
			exit 0
		fi
		;;
	force-stop)
		# First try to stop gracefully the program
		$0 stop
		if running; then
			# If it's still running try to kill it more forcefully
			log_daemon_msg "Stopping (force) $DESC" "$NAME"
			errcode=0
			force_stop || errcode=$?
			log_end_msg $errcode
		fi
		;;
	restart|force-reload)
		log_daemon_msg "Restarting $DESC" "$NAME"
		errcode=0
		stop_server || errcode=$?
		# Wait some sensible amount, some server need this
		[ -n "$DIETIME" ] && sleep $DIETIME
		start_server || errcode=$?
		[ -n "$STARTTIME" ] && sleep $STARTTIME
		running || errcode=$?
		log_end_msg $errcode
		;;
	status)

		log_daemon_msg "Checking status of $DESC" "$NAME"
		if running ;  then
			log_progress_msg "running"
			log_end_msg 0
		else
			log_progress_msg "apparently not running"
			log_end_msg 1
			exit 1
		fi
		;;
	*)
		N=/etc/init.d/$NAME
		echo "Usage: $N {start|stop|force-stop|restart|force-reload|status}" >&2
		exit 1
		;;
esac

exit 0
