#!/bin/bash
# ----------------------------------------------------------------------------
# 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/>.
# ----------------------------------------------------------------------------
# 
# Written by Tom Molin <tom.molin@gmail.com> to make sure a disk is writable, timing it with second resolution
# Send any bug fixes or improvements to me and I'll update the script on Nagios Exchange.
# This script breaks the Nagios recommendation not  to wite to disk because it has to.
# 


# Exit levels:
OK=0
WARN=1
ERROR=2	
UNKNOWN=3

function usage
{
	echo "Usage: Write a couple of bytes to file and return write speed
 -F --file <arg>
 -b --bytes NUM
 -w --warnlevel NUM
 -c --criticallevel NUM
 -L LABEL"
}

# Parse input parameters
until [ -z "$1" ]; do

  case "$1" in
   -F|--file)
		# log file to parse
		FILE="$2"
		shift
		;;
   -b|--bytes)
		# What we'll parse for
		BYTES="$2"
		shift
		;;
    -w|--warnlevel)
		WARNLEVEL="$2"
		shift
		;;
    -c|--criticallevel)
		CRITLEVEL="$2"
		shift
		;;
    -L)
		LBL="$2"
		shift
		;;
    *)
		usage
		exit 1
		;;
  esac
  shift
done

if [[ -z "$FILE" ]] || [[ -z "$BYTES" ]] || [[ -z "$WARNLEVEL" ]] || [[ -z "$CRITLEVEL" ]] || [[ -z "$LBL" ]]
 then
	echo "Missing argument"
 	usage
 	exit 1
 fi
if [[ -w "$FILE" ]]
then
 # Lets do a file write and time it
 TIME=$(\date +%s)
 dd if=/dev/zero bs=$BYTES count=1 of=$FILE &> /dev/null
 let STATUS=$(\date +%s)-$TIME

LABEL="| ${LBL}=${STATUS};$WARNLEVEL;$CRITLEVEL;0;"

if [ "$STATUS" -lt "$WARNLEVEL" ];then
        echo "OK - $STATUS $LABEL"
        exit $OK
fi
if [ "$STATUS" -ge "$WARNLEVEL" -a "$STATUS" -lt "$CRITLEVEL" ];then
        echo "WARNING - $STATUS $LABEL"
        exit $WARN
fi
if [ "$STATUS" -ge "$CRITLEVEL" ];then
        echo "CRITICAL - $STATUS $LABEL"
        exit $CRITICAL
fi

echo "UNKNOWN ERROR status ($STATUS)!"
exit $UNKNOWN

else
 touch $FILE && exit $UKNOWN || echo "$FILE is not writable"
 	usage
 	exit 1
 fi