#!/bin/bash

##############################################################################
# Bash script written by Vahid Hedayati April 2013
##############################################################################
# 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 3 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, see <http://www.gnu.org/licenses/>.
##############################################################################
# This script takes:
# <host> <community> <megs>

snmpwalk="/usr/bin/snmpwalk"
snmpget="/usr/bin/snmpget"

function usage() { 
echo "$0 localhost public 100"
echo "where localhost is server"
echo "public is snmp pass"
echo "100 is when it reaches below a 100Mb"
echo "-----------------------------------"
echo "define threshold below limit specific for partitions i.e. boot can be 50mb where as /var I guess we want to catch it at around 1 gig so"
echo "$0 localhost public  1024"

}


server=$1;
pass=$2
limit=$3;

errors_found="";
partitions_found="";
lower_limit=10;
graphtext="|"

if [ $# -lt 3 ]; then
    usage;
    exit 1;
fi

# takes <size> <used> <allocation>
calc_free() {
	echo "$1 $2 - $3 * 1024 / 1024 / p" | dc
}
	IFS=$'\n'
	for results in $($snmpwalk -v2c -c $pass -Oq $server  hrStorageDescr|grep /|egrep -v "(/mnt|/home|/proc|/sys)"); do
		ret_result=${results##*.}
		partitions=${ret_result##* }
		index=${ret_result%% *}
		if [[ $partitions =~ /boot ]]; then
			limit=$lower_limit;
		fi
		IFS=' ';
		args=$($snmpget -v2c -c $pass -Oqv $server hrStorageSize.$index hrStorageUsed.$index hrStorageAllocationUnits.$index | while read oid j ; do printf " $oid" ; done)
		free=$(calc_free$args)
			back_count=$(echo $partitions|grep -o "/"|wc -l)
			if [[ $back_count -ge 2 ]]; then
				gpartition=$(echo "/"${partitions##*/})
			else
				gpartition=$partitions;
			fi

			if [ "$free" -gt "$limit" ]
			then
				graphtext=$graphtext$gpartition"="$free"MB;;;0 "
				partitions_found=$partitions_found" $partitions ($free MB)"
			else
				graphtext=$graphtext$gpartition"="$free"MB;;;0 "
				errors_found=$errors_found" $partitions ($free MB)"
				
			fi
	
	done

	if [ "$errors_found" == "" ]; then
		echo "OK: $partitions_found$graphtext"
		exit 0
	else
		echo "CRITICAL: $errors_found$graphtext";
		exit 2;
	fi