#!/bin/bash
#
# USAGE:
# ./check_hddtemp.sh <device> <warn> <crit>
# Nagios script to get the temperatue of HDD from hddtemp
#
# You may have to let nagios run this script as root
# This is how the sudoers file looks in my debian system:
# nagios  ALL=(root) NOPASSWD:/usr/lib/nagios/plugins/check_hddtemp.sh
#
# Version 1.0

OK=0
WARNING=1
CRITICAL=2
UNKNOWN=3

function usage()
{
	echo "Usage: ./check_hddtemp.sh <device> <warn> <crit>"
}

function check_root()
{
	# make sure script is running as root
	if [ `whoami` != root ]; then
		echo "UNKNOWN: please make sure script is running as root"
		exit $UNKNOWN
	fi
}
function check_arg()
{
	# make sure you supplied all 3 arguments
	if [ $# -ne 3 ]; then
		usage
		exit $OK
	fi
}
function check_device()
{
	# make sure device is a special block
	if [ ! -b $DEVICE ];then
		echo "UNKNOWN: $DEVICE is not a block special file"
		exit $UNKNOWN
	fi
}
function check_warn_vs_crit()
{
	# make sure CRIT is larger than WARN
	if [ $WARN -ge $CRIT ];then
		echo "UNKNOWN: WARN value may not be greater than or equal the CRIT value"
		exit $UNKNOWN
	fi
}

function init()
{
check_root
check_arg $*
check_device
check_warn_vs_crit
}

function get_hddtemp()
{
	# gets temperature and stores it in $HEAT
	# and make sure we get a numeric output
	if [ -x $HDDTEMP ];then
		HEAT=`$HDDTEMP $DEVICE -n`
		case "$HEAT" in
		[0-9]* )
			echo "do nothing" > /dev/null
			;;
		* )
			echo "UNKNOWN: Could not get temperature from: $DEVICE"
			exit $UNKNOWN
			;;
		esac
	else
		echo "UNKNOWN: cannot execute $HDDTEMP"
		exit $UNKNOWN
	fi
}
function check_heat()
{
	# checks temperature and replies according to $CRIT and $WARN
	if [ $HEAT -lt $WARN ];then
		echo "OK: Temperature is below warn treshold ($DEVICE is $HEAT)"
		exit $OK
	elif [ $HEAT -lt $CRIT ];then
		echo "WARNING: Temperature is above warn treshold ($DEVICE is $HEAT)"
		exit $WARNING
	elif [ $HEAT -ge $CRIT ];then
		echo "CRITICAL: Temperature is above crit treshold ($DEVICE is $HEAT)"
		exit $CRITICAL
	else
		echo "UNKNOWN: This error message should never occur, if it does happen anyway, get a new cup of coffee and fix the code :)"
		exit $UNKNOWN
	fi
		
}

# -- Main -- #

HDDTEMP=/usr/sbin/hddtemp
DEVICE=$1
WARN=$2
CRIT=$3


init $*
get_hddtemp
check_heat