#!/bin/sh

#set -e

Swapon ()
{
	if [ "${LIVE_SWAPON}" != "true" ]
	then
		return 0
	fi

	LIVE_SWAPON_DEVICES="${LIVE_SWAPON_DEVICES:-/dev/sd* /dev/vd*}"

	if [ -e /run ]
	then
		# wheezy
		_FSTAB="/root/etc/fstab.d/swap"
	else
		# squeeze
		_FSTAB="/root/etc/fstab"
	fi

	for _DEVICE in $(echo ${LIVE_SWAPON_DEVICES} | sed -e 's|,| |g')
	do
		if [ ! -b "${_DEVICE}" ]
		then
			continue
		fi

		blkid -o udev -p ${_DEVICE%%[0-9]*} | grep -q "^ID_FS_USAGE=raid" && continue

		_MAGIC="$(/bin/dd if=${_DEVICE} bs=4086 skip=1 count=1 2>/dev/null | /bin/dd bs=10 count=1 2>/dev/null)" || continue

		case "${_MAGIC}" in
			SWAPSPACE2|SWAP-SPACE)
				_SWAP_DEVICES="${_SWAP_DEVICES} ${_DEVICE}"
				;;
		esac
	done

	# Remove all auto swap entries
	if grep -qs "swap swap" "${_FSTAB}"
	then
		grep -v "swap swap" "${_FSTAB}" > "${_FSTAB}".tmp
		mv "${_FSTAB}".tmp "${_FSTAB}"
	fi

	# Add new swap entries
	for _DEVICE in ${_SWAP_DEVICES}
	do
		echo "${_DEVICE} swap swap defaults 0 0" >> "${_FSTAB}"
	done
}