#!/bin/sh -e

export LIBVIRT_DEFAULT_URI="qemu:///system"
PROCOWNER="$(id -un):$(id -gn)"
#TMP_DIR=/srv/kvm_local/backups
LOCKFILE=/var/lock/$(basename $0)

if [ -t 1 ]; then
	VERBOSE=1
else
	VERBOSE=0
fi

msg() {
	echo "$(date '+%Y-%m-%d %H:%M:%S')$@"
}

#if [ ! -d $TMP_DIR ]; then
#	echo "error: no tmp directory: $TMP_DIR" >&2
#	exit 1
#fi

echo checking lockfile $LOCKFILE

[ "${FLOCKER}" != "$0" ] && exec env FLOCKER="$0" flock -en $LOCKFILE "$0" "$@" || :

echo locked as pid $$

DOMLIST=$(virsh list --state-running --without-managed-save --persistent --name)
#DOMLIST=migration-test

[ ! -z "$1" ] && DOMLIST="$1"

echo domain list: $DOMLIST

DST_ROOT=/srv/kvm_backups
DST_BASE=$DST_ROOT/backups
DST_QEMU=$DST_ROOT/qemu

if [ ! -d $DST_BASE ]; then
	echo "error: no base directory: $DST_BASE" >&2
	exit 1
fi

mkdir -p $DST_QEMU

if [ ! -d $DST_QEMU ]; then
	echo "error: no base qemu directory: $DST_QEMU" >&2
	exit 1
fi

for dom in $DOMLIST; do
	echo ""
	msg " = processing $dom..."

	if virsh domblklist $dom >/dev/null; then

		DST_DIR=$DST_BASE/$dom

		SNAPNAME=$(date +%Y%m%d-%H%M%S)
		SNAPYEAR=$(date +%Y)

		mkdir -p $DST_DIR

		if [ ! -d $DST_DIR ]; then
			echo "error: can't create dst dir: $DST_DIR" >&2
			exit 2
		fi

		SKIPFILE=/var/tmp/backup-skip.$dom
#
#		rm -f -- $SKIPFILE
#
#		virsh domblklist $dom | egrep '[svh]d[a-z]' | while read BLKID BLKPATH; do
#			BLKOWNER=$(stat --format '%U:%G' $BLKPATH)
#
#			if [ $BLKOWNER != $PROCOWNER ]; then
#				echo "error: ownership of $BLKPATH ($BLKOWNER) doesn't match $PROCOWNER." >&2
#				echo "error: skipping this domain for now (skipfile: $SKIPFILE)." >&2
#
#				touch $SKIPFILE
#			fi
#		done

		TSTART=$(date +%s)

		if [ ! -e $SKIPFILE ]; then

			msg " * saving latest domain definition to $DST_QEMU/$dom.xml"
			virsh dumpxml --inactive $dom > $DST_QEMU/$dom.xml

			msg " * backing up domain definition to $DST_DIR/$dom-$SNAPNAME.xml"
			virsh dumpxml --inactive $dom > $DST_DIR/$dom-$SNAPNAME.xml

			if virsh undefine $dom >/dev/null; then

				virsh domblklist $dom | egrep '[svh]d[a-z]' | while read BLKID BLKPATH; do
					if [ -f $BLKPATH ]; then
						msg " * processing volume $BLKID / $BLKPATH ($(du -hs $BLKPATH | cut -f 1))..."

						DSTFPATH=$DST_DIR/$(basename $BLKPATH)-$SNAPNAME

						msg " * performing blockcopy of $BLKPATH to $DSTFPATH..."

						if [ $VERBOSE = 1 ]; then
							virsh blockcopy $dom $BLKID $DSTFPATH --transient-job --wait --verbose --finish || ( echo "error: failed to blockcopy $BLKPATH." >&2 && exit 101 )
						else
							virsh blockcopy $dom $BLKID $DSTFPATH --transient-job --wait --finish >/dev/null || ( echo "error: failed to blockcopy $BLKPATH." >&2 && exit 101 )
						fi

						RC=$?

						msg " * blockcopy RC: $RC"

						if [ "$RC" = "0" -a -f $DSTFPATH ]; then
							BKBLKPATH=$DST_ROOT/$(basename $BLKPATH)

							msg " * linking $DSTFPATH to $BKBLKPATH..."

							[ -f $BKBLKPATH ] && rm -f -- $BKBLKPATH

							ln $DSTFPATH $BKBLKPATH
						else
							echo "error: unable to link $DSTFPATH: block operation failed and/or file not found" >&2
						fi

						#msg " * saving $DSTFPATH to $DST_DIR/$(basename $TMPFPATH).tar"
						#nice tar -C $(dirname $TMPFPATH) -cSf $DST_DIR/$(basename $TMPFPATH).tar $(basename $TMPFPATH) || echo error: failed to archive $TMPFPATH. >&2

						msg " * cleaning up $DST_DIR..."
						#rm -f -- $TMPFPATH
						find $DST_DIR -type f -mtime +7 \( -name '*.qcow2-*' -o -name '*.xml' \) -delete
					elif [ $BLKPATH != "-" ]; then
						echo "error: base block path not found: $BLKPATH, skipping." >&2
					fi
				done

				virsh define $DST_DIR/$dom-$SNAPNAME.xml >/dev/null

				msg " = completed in:" $(date "+%M:%S" -d @$(( $(date +%s) - $TSTART )) )

				msg " + finished."
			else
				echo "could not undefine domain, skipping." >&2
			fi
		fi
	else
		echo "error: unable to query blocklist of domain $dom." >&2
	fi

done