check_disk.sh

#!/usr/bin/env bash
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

PROGNAME=`basename $0`
VERSION="version 0.93"
AUTHOR="by Radu MARINESCU [email protected]"
#############################
# Program paths. If left empty the script tries to find the programs
# in the PATH. Fill in the correct paths only if needed.
#############################
#usually /bin/awk or /usr/bin/awk
AWK=""
#usually /bin/grep or /usr/bin/grep
GREP=""
#usually /bin/df
DF=""
#############################

if [ ${#AWK} == 0 ] #the variable AWK is not defined; trying to find awk in the PATH
then
    AWK=`which awk 2>&1`
    AWK_EXISTS=$?
    if [ "$AWK_EXISTS" != 0 ] || [ ${#AWK} == 0 ] #awk is not in the PATH or the variable AWK is empty
    then
        echo "Error! Can't find awk."
        exit 3
    fi
fi

if [ ${#GREP} == 0 ] #the variable GREP is not defined; trying to find grep in the PATH
then
    GREP=`which grep 2>&1`
    GREP_EXISTS=$?
    if [ "$GREP_EXISTS" != 0 ] || [ ${#GREP} == 0 ] #grep is not in the PATH or the variable GREP is empty
    then
        echo "Error! Can't find grep."
        exit 3
    fi
fi

if [ ${#DF} == 0 ] #the variable DF is not defined; trying to find df in the PATH
then
    DF=`which df 2>&1`
    DF_EXISTS=$?
    if [ "$DF_EXISTS" != 0 ] || [ ${#DF} == 0 ] #df is not in the PATH or the variable DF is empty
    then
        echo "Error! Can't find df."
        exit 3
    fi
fi


#############################
# Functions
#############################

print_version() {
    echo "$VERSION $AUTHOR"
}


print_help() {
print_version $PROGNAME $VERSION
echo ""
echo "$PROGNAME is a Nagios plugin used to check disk used space by"
echo "processing the output of \"df\" command. It runs on UNIX, Linux"
echo "and BSD platforms and reports the following performance data:"
echo "- total disk space (Bytes)"
echo "- currently used disk space (Bytes)"
echo "- currently used disk space (%)"
echo " "
echo "$PROGNAME [-v] [-h] [-w UsedSpaceWarning] [-c UsedSpaceCritical] [-p Partition]"
echo " "
echo "Options:"
echo "  --version|-v)"
echo "    prints the program version"
echo "  --help|-h)"
echo "    prints this help information"
echo "  -w)"
echo "    warning threshold (in percents without % sign) for used space"
echo "  -c)"
echo "    critical threshold (in percents without % sign) for used space"
echo "  -p)"
echo "    disk partition to check"
echo " "
exit 3
}


# float number comparison
function fcomp() {
    $AWK -v n1=$1 -v n2=$2 'BEGIN{ if (n1<=n2) exit 0; exit 1}'
}


#formats bytes => KBytes, MBytes, GBytes, TBytes
function btokmgt() {
    if [ $1 -lt 1024 ] #Bytes
    then
        echo "${1}B"
    elif [ $1 -lt 1048576 ] #KBytes
    then
        echo "$1" | $AWK '{printf "%.1fKB", $1/1024}'
    elif [ $1 -lt 1073741824 ] #MBytes
    then
        echo "$1" | $AWK '{printf "%.1fMB", $1/1048576}'
    elif [ $1 -lt 1099511627776 ] #GBytes
    then
        echo "$1" | $AWK '{printf "%.1fGB", $1/1073741824}'
    elif [ $1 -lt 1125899906842624 ] #TBytes
    then
        echo "$1" | $AWK '{printf "%.1fTB", $1/1099511627776}'
    fi
}
#############################


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

while test -n "$1"; do
    case "$1" in
        --help|-h)
            print_help
            exit 3
            ;;
        --version|-v)
            print_version $PROGNAME $VERSION
            exit 3
            ;;
        -w)
            WarnSpace=$2
            shift
            ;;
        -c)
            CritSpace=$2
            shift
            ;;
        -p)
            Partition=$2
            shift
            ;;
        *)
            echo "Unknown argument: $1"
            print_help
            exit 3
            ;;
    esac
    shift
done

if [ ${#Partition} == 0 ]
    then
        echo "Error! You must specify a partition to check! Example: /var or / or /home"
        exit 3
fi

if fcomp $WarnSpace 0
then
    WarnSpace=0
fi
if fcomp 100 $WarnSpace
then
    WarnSpace=100
fi

if fcomp $CritSpace 0
then
    CritSpace=0
fi
if fcomp 100 $CritSpace
then
    CritSpace=100
fi

if fcomp $CritSpace $WarnSpace
then
    WarnSpace=$CritSpace
fi


USEDTXT=`$DF -P -B 1 $Partition 2>&1`
if [ $? != 0 ]
then
    echo "Error! Disk partition $Partition can't be checked. Does it exist?"
    exit 3
fi

SpaceTxt=`echo "$USEDTXT" | $GREP "${Partition}\$"`
SpaceTotal=`echo "$SpaceTxt" | $AWK '{print $2}'`
SpaceUsed=`echo "$SpaceTxt" | $AWK '{print $3}'`
SpaceFree=`echo "$SpaceTxt" | $AWK '{print $4}'`
SpaceUsedProc=`echo "$SpaceTxt" | $AWK '{printf "%.1f", $3*100/$2}'`
SpaceFreeProc=`echo "$SpaceTxt" | $AWK '{printf "%.1f", $4*100/$2}'`

WarnSpaceAbs=`echo "$SpaceTotal $WarnSpace" | $AWK '{printf "%d", $1*$2/100}'`
CritSpaceAbs=`echo "$SpaceTotal $CritSpace" | $AWK '{printf "%d", $1*$2/100}'`

SpaceTotal_F=`btokmgt $SpaceTotal`
SpaceUsed_F=`btokmgt $SpaceUsed`
SpaceFree_F=`btokmgt $SpaceFree`


PerfData="'used space'=${SpaceUsed}B;${WarnSpaceAbs};${CritSpaceAbs};0;${SpaceTotal} 'used space (pct.)'=${SpaceUsedProc}%;${WarnSpace};${CritSpace};0;100"

if fcomp $SpaceUsedProc $WarnSpace
then
    echo "OK; $Partition: total ${SpaceTotal_F}, used ${SpaceUsed_F} (${SpaceUsedProc}%), free ${SpaceFree_F} (${SpaceFreeProc}%) | $PerfData"
    exit 0
fi

if fcomp $WarnSpace $SpaceUsedProc && fcomp $SpaceUsedProc $CritSpace
then
    echo "LowDiskSpace WARNING: $Partition total ${SpaceTotal_F}, used ${SpaceUsed_F} (${SpaceUsedProc}%>${WarnSpace}%), free ${SpaceFree_F} (${SpaceFreeProc}%) | $PerfData"
    #echo "LowDiskSpace WARNING: $Partition total ${SpaceTotal_F}, used ${SpaceUsed_F},  free ${SpaceFree_F} "
    #echo "LowDiskSpace WARNING: Low space"
    exit 1
fi

if fcomp $CritSpace $SpaceUsedProc
then
    echo "CRITICAL; $Partition: total ${SpaceTotal_F}, used ${SpaceUsed_F} (${SpaceUsedProc}%>${CritSpace}%), free ${SpaceFree_F} (${SpaceFreeProc}%) | $PerfData"
    exit 2
fi