#!/bin/bash
read -p "Drive to backup: " DRIVE_TO_BACKUP
read -p "Location of backup: " BACKUP_LOCATION

DEVICE_NAME=$(basename $DRIVE_TO_BACKUP)

# Create empty dir
empty_dir=$(mktemp -d)

BACKUP_LOCATION="${BACKUP_LOCATION}-$(date +'%Y-%m-%d').sqsh"
CHECKSUM_FILE="$DEVICE_NAME.img.cksum"

echo Backup: $DRIVE_TO_BACKUP
echo To: $BACKUP_LOCATION

mksquashfs $empty_dir $BACKUP_LOCATION -p "$DEVICE_NAME.img f 444 root root dd if=$DRIVE_TO_BACKUP bs=4M" -p "$CHECKSUM_FILE f 444 root root dd if=$DRIVE_TO_BACKUP | cksum"

# Check Backup integrity by mounting and recalculating checksum from img and dev and compare to .img .img.cksum dev
echo
echo Checking Backup integrity ...
echo

BACKUP_MNT=$(mktemp -d)
mount -o ro $BACKUP_LOCATION $BACKUP_MNT

# Recalculate checksums
DRIVE_CKSUM=$(dd if=$DRIVE_TO_BACKUP | cksum)

# Compare checksums
diff <(echo $DRIVE_CKSUM) <(cat $BACKUP_MNT/$CHECKSUM_FILE)
if [ $? -ne 0 ]; then
	echo -e "\e[1;41m Backup not consistent! \e[0m"
	exit -1
fi

# Recalculate checksums
IMG_CKSUM=$(dd if=$BACKUP_MNT/$DEVICE_NAME.img | cksum)

# Compare checksums
diff <(echo $IMG_CKSUM) <(cat $BACKUP_MNT/$CHECKSUM_FILE)
if [ $? -ne 0 ]; then
	echo -e "\e[1;41m Backup not consistent! \e[0m"
	exit -1
fi

umount $BACKUP_LOCATION

echo -e "\e[1;42m Backup complete \e[0m"