copy_previous() {
	if [ ! -d "${PREV_ROOTFS_DIR}" ]; then
		echo "Previous stage rootfs not found"
		false
	fi
	mkdir -p "${ROOTFS_DIR}"
	rsync -aHAXx --exclude var/cache/apt/archives "${PREV_ROOTFS_DIR}/" "${ROOTFS_DIR}/"
}

unmount() {
	if [ -z "$1" ]; then
		DIR=$PWD
	else
		DIR=$1
	fi

	while mount | grep -q "$DIR"; do
		local LOCS
		LOCS=$(mount | grep "$DIR" | cut -f 3 -d ' ' | sort -r)
		for loc in $LOCS; do
			umount "$loc"
		done
	done
}

unmount_image() {
	sync
	sleep 1
	local LOOP_DEVICES
	LOOP_DEVICES=$(losetup -j "${1}" | cut -f1 -d':')
	for LOOP_DEV in ${LOOP_DEVICES}; do
		if [ -n "${LOOP_DEV}" ]; then
			local MOUNTED_DIR
			MOUNTED_DIR=$(mount | grep "$(basename "${LOOP_DEV}")" | head -n 1 | cut -f 3 -d ' ')
			if [ -n "${MOUNTED_DIR}" ] && [ "${MOUNTED_DIR}" != "/" ]; then
				unmount "$(dirname "${MOUNTED_DIR}")"
			fi
			sleep 1
			losetup -d "${LOOP_DEV}"
		fi
	done
}

on_chroot() {
	if ! mount | grep -q "$(realpath "${ROOTFS_DIR}"/proc)"; then
		mount -t proc proc "${ROOTFS_DIR}/proc"
	fi

	if ! mount | grep -q "$(realpath "${ROOTFS_DIR}"/dev)"; then
		mount --bind /dev "${ROOTFS_DIR}/dev"
	fi
	
	if ! mount | grep -q "$(realpath "${ROOTFS_DIR}"/dev/pts)"; then
		mount --bind /dev/pts "${ROOTFS_DIR}/dev/pts"
	fi

	if ! mount | grep -q "$(realpath "${ROOTFS_DIR}"/sys)"; then
		mount --bind /sys "${ROOTFS_DIR}/sys"
	fi

	capsh --drop=cap_setfcap "--chroot=${ROOTFS_DIR}/" -- "$@"
}

export -f copy_previous
export -f unmount
export -f unmount_image
export -f on_chroot