User callback script for BackInTime handling mount & unmount of encrypted backup target and using the modify date of a file to communicate last snapshot date.

user-callback

#!/bin/bash
#    Copyright (c) 2012-2015 Germar Reitze
#    Mount/unmount implementation 2019 Emil "AngryAnt" Johansen
#
#    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 2 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, write to the Free Software Foundation, Inc.,
#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.


#Script should return 0 if everything is alright. Returncode !0 will cancle
#the running snapshot (BIT version >1.1.0).

profile_id="$1"
profile_name="$2"
reason="$3"

device="SPECIFY"
key_path="SPECIFY"
mapname="back-in-time"
mount_dir="/mnt/back-in-time"
last_snapshot_file="SPECIFY"

case $reason in
    1) #Backup process begins
        ;;
    2) #Backup process ends
        ;;
    3) #A new snapshot was taken
        snapshot_id="$4"
        snapshot_name="$5"
        sudo touch $last_snapshot_file
        ;;
    4) #There was an error
        errorcode="$4"
        case $errorcode in
            1) #ERROR The application is not configured
              ;;
            2) #ERROR A 'take snapshot' process is already running
              ;;
            3) #ERROR Can't find snapshots folder (is it on a removable drive ?)
              ;;
            4) #ERROR A snapshot for 'now' already exist
              ;;
        esac
        ;;
    5) #backintime-qt4 (GUI) started
        ;;
    6) #backintime-qt4 (GUI) closed
        ;;
    7) #Mount drives
        sudo cryptsetup open $device $mapname --key-file=$key_path && mkdir $mount_dir && mount /dev/mapper/$mapname $mount_dir
        ;;
    8) #Unmount the drives
        sudo umount $mount_dir && rm -r $mount_dir
        sudo cryptsetup close $mapname
        ;;
esac