#!/bin/sh

set -e

# Read cmdline
for _PARAMETER in $(cat /proc/cmdline)
do
	case "${_PARAMETER}" in
		module=*)
			_MODULE="${_PARAMETER#module=}"
			;;
	esac
done

# Assemble filesystems
if [ -z "${_MODULE}" ]
then
	_FILESYSTEMS="/live/image/live/filesystem.squashfs"
else
	for _FILESYSTEM in _MODULE
	do
		_FILESYSTEMS="${_FILESYSTEMS} /live/image/live/${_FILESYSTEM}"
	done
fi

# Exit if system is not debian live
if [ ! -d /live/image ]
then
	echo "E: live-toram only works on Debian Live systems."

	exit 1
fi

# Exit if filesystem not accessible
for _FILESYSTEM in ${_FILESYSTEMS}
do
	if [ ! -r ${_FILESYSTEM} ]
	then
		echo "E: ${_FILESYSTEM}: No such file"
		echo "I: live-toram already run?"

		exit 1
	fi
done

# Exit if user is unprivileged
if [ "$(id -u)" -ne 0 ]
then
	echo "E: need root privileges"

	exit 1
fi

# Exit if not enough free memory
_SIZE=0

for _FILESYSTEM in ${_FILESYSTEMS}
do
	_SIZE="$((${_SIZE} + $(du ${_FILESYSTEM} | awk '{ print $1 }')))"
	_MEMORY="$(awk '/MemFree/ { print $2 }' /proc/meminfo)"
done

case ${@} in
	-f|--force)
		echo "W: Ignoring memory constrains as requested"
		;;

	*)
		if [ $_MEMORY -lt $_SIZE ]
		then
			echo "E: not enough free memory available."
			echo "I: images need ${_SIZE}kB, free memory is ${_MEMORY}kB."

			exit 1
		fi
		;;
esac

# Copying image to memory
echo "P: Copying images to memory."
echo "P: This may take a while..."

# FIXME: doesn't work with multiple filesystems
for _FILESYSTEM in ${_FILESYSTEMS}
do
	if [ ! -x "$(which rsync 2>/dev/null)" ]
	then
		rsync -a --progress ${_FILESYSTEM} /tmp/live
	else
		cp -av ${_FILESYSTEM} /tmp/live
	fi

LANGUAGE=C LANG=C LC_ALL=C perl << EOF
open LOOP, '</dev/loop0' or die $!;
open DEST, '</tmp/live' or die $!;
ioctl(LOOP, 0x4C06, fileno(DEST)) or die $!
close LOOP;
close DEST;
EOF

done

# Unmounting live media
_DEVICE="$(awk '/\/live\/image / { print $1 }' /proc/mounts)"

if [ -d /live/image ]
then
	umount /live/image
	rmdir --ignore-fail-on-non-empty /live/image || true
fi

# Ejecting live media if it is not an optical device
if [ "$(expr substr ${_DEVICE} 1 2)" != "sd" ] && \
   ! readlink /sys/block/$(expr substr ${_DEVICE} 6 3) | grep -q usb
then
	if [ ! -x "$(which rsync 2>/dev/null)" ]
	then
		eject -p -m ${_DEVICE} >/dev/null 2>&1
	fi
fi