#!/bin/bash
# -------------------------------------------------------------------------
# MONITORING FILESYSTEM CHECK FOR THE LINUX/UNIX MACHINES.
# THE SCRIPT DETECTS THE MOUNTPOINTS AUTOMATICALLY. 
# SCRIPT WORK WITH NAGIOS/ICINGA BUT COULD BE USED WITH ANY OTHER MONITORING TOOL
# ----------------------------------------------------------------------
# Piotr Mozdzynski  p i o t v [at] k c n . p l
#

# Exclude list , separated with the "|" - An example: EXCLUDE="/dev/hdd1|/dev/hdc5"
EXCLUDE="/boot/efi|/dev/sxa"

## THRESHOLD ##
# Accept external threshold input in decimal ( without % ) , for example:
# ./check_disk 50 75 
# above will set the the warning to 50% and criticat to 75%



# if the imput was not specified , set the defaut warning to 90% and critical to 95%

if [ -z "$1" ] || [ -z "$2" ]
then
WARNING=90
CRITICAL=95
else 
WARNING=$1
CRITICAL=$2
fi


# clean previous results from temporary file and set the new one
rm -rf .disk.check.result
touch .disk.check.result


# exit codes 
exit_ok()
{
echo "OK , the filesystem on $(hostname) as on $(date)"  && exit 0
}

exit_warning()
{
cat .disk.check.result | while read line 
do 
echo "$line" 
done 
exit 1
}

exit_critical()
{
cat .disk.check.result | while read line 
do 
echo "$line" 
done 
exit 2
}


# Store the temporary output into control file. In case of both conditions found store warnings on the second line of the file. 
# critical messages will aways overwrite warnings, warnings will be stored on second line till the critical are fixed.

save_warning()
{
# output warning into the control file
echo "WARNING Out of space \"$partition ($usep%)\" on $(hostname) as on $(date) " >> .disk.check.result
}

save_critical()
{
# always overwrite the warning with the critical on the control file. ( after cleared critical , the warning will show on the next check ) 
echo "CRITICAL Out of space \"$partition ($usep%)\" on $(hostname) as on $(date) " > .disk.check.result
}



# loop function and output to control file
function loop() {
while read output;
do
usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1)
partition=$(echo $output | awk '{print $2}')
if [ "$usep" -gt "$WARNING" ] && [ "$usep" -lt "$CRITICAL" ]  ; 
then
save_warning
elif [ $usep -ge $CRITICAL ] ; then
save_critical
fi
done
}



# run the loop function with the excluded from checking partitions

if [ "$EXCLUDE" != "" ] ; then
  df -hP |  grep -vE "^[^/]|tmpfs|cdrom|${EXCLUDE}" | awk '{print $5 " " $6}' | loop
else
  df -hP |  grep -vE "^[^/]|tmpfs|cdrom"| awk '{print $5 " " $6}' | loop
fi


# read the .disk.check.result to display correct exit status.
value=$(cat .disk.check.result)
case $value in
*CRITICAL*) 
exit_critical ;;
*WARNING*) 
exit_warning ;;
*)
exit_ok ;;
esac

#save the OK ( not functionally needed , only for debug )
echo "OK" > .disk.check.result