#!/bin/bash

#   Check Time Machine Currency
#   by Jedda Wignall
#   http://jedda.me

#   Additional Code by:
#   Dan Barrett
#   http://yesdevnull.net

#   Modified for GFI RMM usage by:
#   Devin Campbell
#   Dayton Backup & IT
#   http://daytonbackup.com

#   v1.4 - 17 Nov 2014
#   Updated for Yosemite. Old check for OS X version found 10.10 to 
#   be less than 10.9 (mathematically accurate). The method of checking
#   Time Machine is the same as in Mavericks, only the version checking
#   has changed.

#   v1.3 - 14 Dec 2013
#   Changed exit codes for GFI usage (errors should be over 1000)
#   Added /Library/Preferences/com.gfi.MaxRMM.TimeMachine.plist to store last
#   backup date so that the check doesn't fail whenever the Time Machine
#   location is disconnected.

#   v1.2 - 21 Nov 2013
#   Updated with support for OS X Mavericks (10.9)

#   v1.1 - 3 May 2012
#   Cleaned up the output to provide a last backed up date. Error checking for non-supplied flags.

#   v1.0 - 3 May 2012
#   Initial release.

#   This script checks the Time Machine results file on a Mac, and reports if a backup has completed within a number of minutes of the current time.
#   Very useful if you are monitoring client production systems and want to ensure backups are occurring.

#   Arguments:
#   Critical threshold in minutes

#   Example:
#   ./check_time_machine_currency.sh 1440

#   Supports:
#   * OS X 10.6
#   * OS X 10.7
#   * OS X 10.8
#   * OS X 10.9
#   * OS X 10.10

critMinutes=$1;

if [ "$critMinutes" == "" ]
then
    printf "ERROR - You must provide a critical threshold in minutes!\n"
    exit 1001
fi

# Check to see if we're running Mavericks as Time Machine runs a little differently
osVersion=`sw_vers -productVersion | grep -E -o "[0-9]+\.[0-9]+"`
isMavericks=`echo $osVersion '== 10.9' | bc -l`
isYosemite=`echo $osVersion '== 10.10' | bc -l`
currentDate=`date +%s`

if [ $isMavericks -eq 1 ] || [ $isYosemite -eq 1 ]
then
    # 10.9+ Check
    if [ $isMavericks -eq 1 ]
    then
      printf "Running on Mavericks.\n"
    elif [ $isYosemite -eq 1 ]
    then
      printf "Running on Yosemite.\n"
    fi
    lastBackupDateString=`tmutil latestbackup | grep -E -o "[0-9]{4}-[0-9]{2}-[0-9]{2}-[0-9]{6}"`

    if [ "$lastBackupDateString" == "" ]
    then
                printf "Looking for last backup in /Library/Preferences/com.gfi.MaxRMM.TimeMachine.\n"
                lastBackupDateString=`defaults read /Library/Preferences/com.gfi.MaxRMM.TimeMachine LastBackup`
        if [ "$lastBackupDateString" == "" ]
        then
          printf "CRITICAL - Time Machine has not completed a backup on this Mac!\n"
          exit 1002
        fi
    fi

    lastBackupDate=`date -j -f "%Y-%m-%d-%H%M%S" $lastBackupDateString "+%s"`
    `defaults write /Library/Preferences/com.gfi.MaxRMM.TimeMachine LastBackup -string ''$lastBackupDateString''`
else
    # < 10.9 Check
    printf "Running on pre-Mavericks.\n"
    lastBackupDateString=`defaults read /private/var/db/.TimeMachine.Results BACKUP_COMPLETED_DATE`

    if [ "$lastBackupDateString" == "" ]
    then
        printf "CRITICAL - Time Machine has not completed a backup on this Mac!\n"
        exit 1002
    fi

    lastBackupDate=`date -j -f "%Y-%m-%e %H:%M:%S %z" "$lastBackupDateString" "+%s"`
fi


diff=$(($currentDate - $lastBackupDate))
critSeconds=$(($critMinutes * 60))

if [ "$diff" -gt "$critSeconds" ]
then
    printf "CRITICAL - Time Machine has not backed up since `date -j -f %s $lastBackupDate` (more than $critMinutes minutes)!\n"
    exit 1003
fi

if [ "$lastBackupDate" != "" ]
then
    printf "OK - A Time Machine backup has been taken within the last $critMinutes minutes. (`date -j -f %s $lastBackupDate`)\n"
    exit 0
else
    printf "CRITICAL - Could not determine the last backup date for this Mac.\n"
    exit 1002
fi