#!/bin/bash
# $Header: $
# vim:nu:ai:sw=4:ts=4:
#
# Nagios check script for services and processes
# Created by Wolfram Schlich <wschlich@gentoo.org>
# Distributed under the terms of the GNU General Public License v3
#
# External dependencies:
# - nice
# - pgrep (for process check)
#

##
## nagios state specific exit codes
##

declare -i state_ok=0
declare -i state_warning=1
declare -i state_critical=2
declare -i state_unknown=3
declare -i state_dependent=4

##
## functions
##

function usage() {
	echo
	echo "Usage: ${0##*/} <rc:all|rc:SERVICE|proc:REGEXP>"
	echo
}

function checkargs() {
	if [[ -z "${service}" ]]; then
		usage
		exit ${state_unknown}
	fi
}

##
## main()
##

service="${1}"; shift

checkargs

case "${service}" in
	## check ALL enabled init scrpits
	rc:all)
		declare -a rc_started
		declare -a rc_stopped
		declare -i check_time=0
		declare -i check_start=${SECONDS}
		if [[ -e /lib/librc.so ]]; then
			## baselayout-2/OpenRC
			current_softlevel=$(rc-status -r)
		elif [[ -f /var/lib/init.d/softlevel ]]; then
			## baselayout-1
			current_softlevel=$(</var/lib/init.d/softlevel)
		else
			echo "ERROR - unable to determine current softlevel"
			exit ${state_unknown}
		fi
		for rc_script in /etc/runlevels/${current_softlevel}/*; do
			rc_service=${rc_script##*/}
			if ! nice -n 19 ${rc_script} --quiet status &>/dev/null; then
				rc_stopped=( ${rc_stopped[@]} ${rc_service} )
			else
				rc_started=( ${rc_started[@]} ${rc_service} )
			fi
		done
		declare -i check_finish=${SECONDS}
		let 'check_time = check_finish - check_start'
		if [ ${#rc_stopped[@]} -gt 0 ]; then
			echo "CRITICAL - rc scripts [${rc_stopped[@]}] STOPPED"
			exit ${state_critical}
		else
			echo "OK - all enabled rc scripts started (check took ${check_time}s)"
			exit ${state_ok}
		fi
		;;
	## check a single init script
	rc:*)
		rc_service=${service#rc:}
		rc_script=/etc/init.d/${rc_service}
		if [[ ! -x ${rc_script} ]]; then
			echo "rc script '${rc_service}' not executable"
			exit ${state_unknown}
		elif ! nice -n 19 ${rc_script} --quiet status &>/dev/null; then
			echo "CRITICAL - rc script '${rc_service}' STOPPED"
			exit ${state_critical}
		else
			echo "OK - rc script '${rc_service}' started"
			exit ${state_ok}
		fi
		;;
	## check for processes
	proc:*)
		proc=${service#proc:}
		if [[ ! -x "$(type -p pgrep 2>/dev/null)" ]]; then
			echo "ERROR - pgrep not executable"
			exit ${state_unknown}
		elif ! pgrep -fx "${proc}" &>/dev/null; then
			echo "ERROR - no process(es) running"
			exit ${state_critical}
		else
			echo "OK - '${proc}' running"
			exit ${state_ok}
		fi
		;;
	## unknown services
	*)
		echo "service '${service}' unknown/unsupported"
		exit ${state_unknown}
		;;
esac

## should never reach this
echo "ERROR - there's an error in the matrix!"
exit ${state_unknown}