#!/bin/bash
#
# check_pidfile: PID file and process checker plugin for Nagios
# author: 2012 Chrisian Birchinger <cbirchinger@netswarm.net>
# version: 0.1
#
# The really specific usage of "ps" makes this plugin probably
# fail on anything other than "ps" from Linux procps, but it's
# rather easy to add some hacky sed/awk parsing if required.
#
# Example:
# ./check_pidfile /var/run/sshd.pid:sshd /var/run/acpid.pid
# OK: acpid=13281 sshd(sshd)=2707
#
# "procname" is optional but recommended
# Arguments can be separated by space or comma (easier for NRPE)


if [[ -z $1 ]]; then
	echo "Usage: $(basename $0) pidfile[:procname] [ pidfile2[:procname2] pidfile3[:procname3] ... ]"
	exit 3
fi

# Allow space or comma seperated (for easier NRPE argument passing) argument lists
pidfiles="${@/,/ }"

oklist=''

for pf in $pidfiles; do
	name=''
	if [[ $pf == *:* ]]; then
		name=${pf/*:/}
		pf=${pf/:*/}
	fi

	if [[ ! -f $pf ]]; then
		echo "ERROR: PID file $pf does not exist. (or directory permissions?)"
		exit 2
	elif [[ ! -r $pf ]]; then
		echo "ERROR: PID file $pf is not readable. (permissions?)"
		exit 2
	else
		pid=$(head -n1 < $pf)
		if ! cmd="$(ps -o comm --no-headers -p $pid)"; then
			echo "ERROR: PID $pid from $(basename $pf) is not running"
			exit 2
		else
			if [[ -n $name ]];then
				if [[ $name != $cmd ]]; then
					echo "ERROR: Running command name \"$cmd\" does not match \"$name\""
					exit 2
				else
					oklist="$(basename $pf .pid)($name)=$pid $oklist"
				fi
			else
				oklist="$(basename $pf .pid)=$pid $oklist"
			fi
		fi
	fi
done

echo "OK: $oklist"
exit 0