remote-backup/remote-backup

#!/bin/bash
# ----------------------------------------------------------------------
# mikes handy rotating-filesystem-snapshot utility
# ----------------------------------------------------------------------
# this needs to be a lot more general, but the basic idea is it makes
# rotating backup-snapshots of /home whenever called
# ----------------------------------------------------------------------

#unset PATH	# suggestion from H. Milz: avoid accidental use of $PATH

# ------------- system commands used by this script --------------------

###BEGIN: generic tool checker
# FIXME: To reuse this function, be sure to edit this line (space separated
# list).
needed_tools="id echo mount rm mv cp touch rsync"
#
# One shall not need edit anything below this line
###
checktools() {
	# This functions attempts to be generic enough to be reused in any program
	# that needs to check that specific tools are present on the system
	# and can be found in the PATH 
	var=$(echo $1 | tr '[:lower:]' '[:upper:]')
	echo -n "# Looking for $1... "
	local_var="$(which $1)"
	eval $var="$local_var"
	if [ -z "$local_var" ]
	then
		echo 'NOT FOUND!'
		NOTFOUND="$NOTFOUND$1 "
		DIE=1
	else
		echo "$local_var"
		FOUND="$FOUND$1 "
	fi
	unset local_var
}

for tool in $needed_tools
do
	checktools "$tool"
done

echo
echo "# Found $FOUND"
echo

if [ -n "$DIE" ]
then
	echo "Some tools were not found, please check your installation" >&2
	echo "Needed tools: $needed_tools" >&2
	echo -n "Not found:" >&2
	for tool in $NOTFOUND
	do
		echo -n " $tool" >&2
	done
	echo '!' >&2
	exit 127
fi
###END: generic tool checker

while getopts 'e:h' opt
do
	case $opt in
		e)
			EMERG="$OPTARG"
		;;
		h)
			help
		;;
	esac
done

doBackup() {
	config="$1"
	if [ ! -e "$config" ]
	then
		echo "No backups defined, dying." >&2
		exit 128
	fi
	source /etc/remote-backup/defaults.conf
	source "$config"

	echo "Debut de backup de ${REMOTE_LOCATION} vers ${SNAPSHOT_RW}/${NAME}/ a $(date +"%H:%M, le %d/%m/%Y")"

	if [[ "$REMOUNT" == "true" ]]
	then
# attempt to remount the RW mount point as RW; else abort
		$MOUNT -o remount,rw "$MOUNT_DEVICE" "$SNAPSHOT_RW" ;
		if (( $? ))
		then
			echo "snapshot: could not remount $SNAPSHOT_RW readwrite" >&2
			return 1
		fi
	fi

	if [ ! -d "$SNAPSHOT_RW/$NAME" ]
	then
		mkdir -p "$SNAPSHOT_RW/$NAME"
	fi

	if [[ "$2" == emerg ]]
	then
		runBackup emerg.$(date +%Y%m%d%H%M)
	else
		rotateBackup
		runBackup daily.0
	fi

# now remount the RW snapshot mountpoint as readonly
	if [[ "$REMOUNT" == "true" ]]
	then
		$MOUNT -o remount,ro "$MOUNT_DEVICE" "$SNAPSHOT_RW"
		if (( $? ))
		then
			echo "snapshot: could not remount $SNAPSHOT_RW readonly"
			exit
		fi
	fi

	echo "Fin de backup de ${REMOTE_LOCATION} vers ${SNAPSHOT_RW}/${NAME}/ a $(date +"%H:%M, le %d/%m/%Y")"
	echo '-----------------------------------------------------------------------'
}

rotateBackup() {
# rotating snapshots
	if [ -f "$SNAPSHOT_RW/$NAME/daily.0" ]
	then
		echo "Previous backup failed, skipping rotation."
		rm "$SNAPSHOT_RW/$NAME/daily.0"
	elif [ -f "$SNAPSHOT_RW/$NAME/daily.0/unfinished.remote-backup" ]
	then
		echo "Previous backup interrupted, skipping rotation."
		rm "$SNAPSHOT_RW/$NAME/daily.0/unfinished.remote-backup"
	else
# step 1: delete the oldest snapshot, if it exists:
		if [ -d "$SNAPSHOT_RW/$NAME/daily.${MAX_ROTATE}" ]
		then
			$RM -rf "$SNAPSHOT_RW/$NAME/daily.${MAX_ROTATE}"
		fi

# step 2: shift the snapshots(s) back by one, if they exist
		for backup_number in {$((${MAX_ROTATE}-1))..0}
		do
			if [ -d "$SNAPSHOT_RW/$NAME/daily.${backup_number}" ]
			then
				$MV -f "$SNAPSHOT_RW/$NAME/daily.${backup_number}" \
					"$SNAPSHOT_RW/$NAME/daily.$((${backup_number}+1))"
			fi
		done
	fi
}

runBackup() {
# step 3: rsync from the system, linking to latest snapshot if files are
# identical.
	RSYNC_OPTS="-a --exclude-from=$EXCLUDES --bwlimit=$BWLIMIT"
	
	for (( backup_num=0 ; backup_num <= MAX_ROTATE ; backup_num++ ))
	do
		if [ -d "$SNAPSHOT_RW/$NAME/daily.$backup_num" ]
		then
			RSYNC_OPTS="$RSYNC_OPTS --link-dest=$SNAPSHOT_RW/$NAME/daily.$backup_num"
		fi
	done
	for old_backup in "$SNAPSHOT_RW/$NAME/emerg".*
	do
		if [ -d "$old_backup" ]
		then
			RSYNC_OPTS="$RSYNC_OPTS --link-dest=$old_backup"
		fi
	done
	if (( TIMEOUT ))
	then
		RSYNC_OPTS="$RSYNC_OPTS --timeout=$TIMEOUT"
	else
		RSYNC_OPTS="$RSYNC_OPTS --timeout=1800"
	fi

	$RSYNC							\
		$RSYNC_OPTS					\
		"${REMOTE_LOCATION}"		\
		"$SNAPSHOT_RW/$NAME/$1"
	if	   (( $? == 10 ))	\
		|| (( $? == 12 ))	\
		|| (( $? == 20 ))	\
		|| (( $? == 21 ))	\
		|| (( $? == 22 ))	\
		|| (( $? == 23 ))	\
		|| (( $? == 30 ))
	then
		if [ -d "$SNAPSHOT_RW/$NAME/$1" ]
		then
			touch "$SNAPSHOT_RW/$NAME/$1/unfinished.remote-backup"
		fi
	fi

# step 5: update the mtime of daily.0 to reflect the snapshot time
	$TOUCH "$SNAPSHOT_RW/$NAME/$1"

# and thats it
}

# make sure we're running as root
if [ ! $UID -eq 0 ]
then
	echo "Sorry, must be root.  Exiting..."
	exit
fi

if [ -n "$EMERG" ]
then
	doBackup /etc/remote-backup/"${EMERG//\//_}"/config emerg
else
	for config in /etc/remote-backup/*/config
	do
		doBackup "$config"
	done
fi