#!/bin/sh

# live-snapshot - utility to manage Debian Live systems snapshots
#
#   This program mount a device (fallback to /tmpfs under /mnt/snapshot
#   and save the /live/cow (or a different dir) filesystem in it for reusing
#   in another live-initramfs session. Look at manpage for more info.
#
# Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
# On Debian systems, the complete text of the GNU General Public License
# can be found in /usr/share/common-licenses/GPL-2 file.

PROGRAM="$(basename $0)"
VERSION=0.0.1

# Source live conf
if [ -e /etc/live.conf ]
then
	. /etc/live.conf
else
	USERNAME=$(cat /etc/passwd | grep "999" | cut -f1 -d ':')
	HOSTNAME=$(hostname)
	BUILD_SYSTEM="Debian"
fi

export USERNAME USERFULLNAME HOSTNAME BUILD_SYSTEM

# Source helper functions
helpers="/usr/share/initramfs-tools/scripts/live-helpers"

if [ -e "${helpers}" ]
then
	. "${helpers}"
else
	echo "Error: I cannot found helper functions \"${helpers}\"."
	exit 1
fi

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions

MOUNTP=""
COW=""
DEV=""
DEST=""
TYPE=""
DESKTOP_LINK=""

Header ()
{
	echo "${PROGRAM} - utility to do Debian Live snapshots"
	echo
	echo "Usage: ${PROGRAM} [-c|--cow DIRECTORY] [-d|--device DEVICE] [-o|--output FILE] [-t|--type TYPE]"
	echo "Usage: ${PROGRAM} [-r|--resync-string STRING]"
	echo "Usage: ${PROGRAM} [-h|--help]"
	echo "Usage: ${PROGRAM} [-u|--usage]"
	echo "Usage: ${PROGRAM} [-v|--version]"
}

Usage ()
{
	MESSAGE=${1}

	Header

	echo
	echo "Try \"${PROGRAM} --help\" for more information."

	if [ ! -z "${MESSAGE}" ]
	then
		echo -e "${MESSAGE}"
		exit 1
	else
		exit 0
	fi
}

Help ()
{
	Header

	echo
	echo "Options:"
	echo "  -c, --cow: specifies the copy on write directory (default: /live/cow)."
	echo "  -d, --device: specifies the output snapshot device (default: none)."
	echo "  -o, --output: specifies the output image file (default: ${type} dependent)."
    echo "  -r, --resync-string: internally used to resync previous made snapshots."
	echo "  -t, --type: specifies the snapshot type between \"squashfs\", \"ext2\", \"ext3\" or \"cpio\".gz archive (default: cpio)"
    echo -e "\nLook at live-snapshot(1) man page for more information."

	exit 0
}

Version ()
{
	echo "${PROGRAM}, version ${VERSION}"
	echo
	echo "Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>"
	echo
	echo "This program is free software; you can redistribute it and/or modify"
	echo "it under the terms of the GNU General Public License as published by"
	echo "the Free Software Foundation; either version 2 of the License, or"
	echo "(at your option) any later version."
	echo
	echo "This program is distributed in the hope that it will be useful,"
	echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
	echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
	echo "GNU General Public License for more details."
	echo
	echo "You should have received a copy of the GNU General Public License"
	echo "along with this program; if not, write to the Free Software"
	echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
	echo
	echo "On Debian systems, the complete text of the GNU General Public License"
	echo "can be found in /usr/share/common-licenses/GPL-2 file."
	echo
	echo "Homepage: <http://debian-live.alioth.debian.org/>"

	exit 0
}

Do_snapshot ()
{
	case "${TYPE}" in
		squashfs)
			echo "./tmp/exclude_list" > /tmp/exclude_list
			( cd "${COW}" && find . -name '*.wh.*' >> /tmp/exclude_list )
			mksquashfs "${COW}" "${DEST}" -ef /tmp/exclude_list || exit 1
			rm /tmp/exclude_list
			;;

		cpio)
			( cd "${COW}" && find . -path '*.wh.*' -prune -o -print0 | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" ) || exit 1
			;;

		ext2|ext3)
			DU_DIM="$(du -ks ${COW} | cut -f1)"
			REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
			genext2fs --size-in-blocks=${REAL_DIM} --reserved-blocks=0 --root="${COW}" "${DEST}" || exit 1
			;;

		*)
			echo "Internal error."
			exit 1
			;;
	esac
}

Is_same_mount ()
{
	dir1="$(Base_path ${1})"
	dir2="$(Base_path ${2})"

	if [ "${dir1}" = "${dir2}" ]
	then
		return 0
	else
		return 1
	fi
}

Parse_args ()
{
	# Parse command line
	ARGS="${1}"
	ARGUMENTS="$(getopt --longoptions cow:,device:,output,resync-string:,type:,help,usage,version --name=${PROGRAM} --options c:d:o:t:r:,h,u,v --shell sh -- ${ARGS})"

	if [ "${?}" != "0" ]
	then
		echo "Terminating." >&2
		exit 1
	fi

	eval set -- "${ARGUMENTS}"

	while true
	do
		case "${1}" in
			-c|--cow)
				SNAP_COW="${2}"
				shift 2
				;;

			-d|--device)
				SNAP_DEV="${2}"
				shift 2
				;;

			-o|--output)
				SNAP_OUTPUT="${2}"
				shift 2
				;;

			-t|--type)
				SNAP_TYPE="${2}"
				shift 2
				;;

			-r|--resync-string)
				SNAP_RSTRING="${2}"
				break
				;;

			-h|--help)
				Help
				;;

			-u|--usage)
				Usage
				;;

			-v|--version)
				Version
				;;

			--)
				shift
				break
				;;

			*)
				echo "Internal error."; exit 1 ;;

		esac
	done
}

Mount_device ()
{
	dev="${1}"

	if [ ! -d "${MOUNTP}" ]
	then
		mkdir -p "${MOUNTP}"
	fi

	if [ -z "${dev}" ]
	then
		# create a temp
		mount -t tmpfs -o rw tmpfs "${MOUNTP}"

		if [ ! -L /home/${USERNAME}/Desktop/live-snapshot ]
		then
			ln -s "${MOUNTP}" /home/${USERNAME}/Desktop/live-snapshot
		fi
	else
		if [ -b "${dev}" ]
		then
			try_mount "${dev}" "${MOUNTP}" rw
		fi
	fi
}

Defaults ()
{
	MOUNTP="/mnt/live-snapshot"
	COW="/live/cow"
	DEV=""
	DEST="${MOUNTP}/live-sn.cpio.gz"
	TYPE="cpio"
	DESKTOP_LINK=/home/${USERNAME}/Desktop/live-snapshot

	if [ -n "${SNAP_RSTRING}" ]
	then
		COW=$(echo "${SNAP_RSTRING}" | cut -f1 -d ':')
		DEV=$(echo "${SNAP_RSTRING}" | cut -f2 -d ':')
		DEST=$(echo "${SNAP_RSTRING}" | cut -f3 -d ':')

		case "${DEST}" in
			*.cpio.gz)
				TYPE="cpio"
				;;

			*.squashfs)
				TYPE="squashfs"
				;;

			""|*.ext2|*.ext3)
				TYPE="ext2"
				;;

			*)
				Usage "Unregognized String"
				;;
		esac
	else
		DEF_COW="/live/cow"

		# Bad options handling
		if [ -z "${SNAP_COW}" ]
		then
			COW="${DEF_COW}"
		else
			COW="${SNAP_COW}"
		fi

		case "${SNAP_TYPE}" in
			"cpio"|"squashfs"|"ext2"|"ext3")
				TYPE="${SNAP_TYPE}"
				;;

			"")
				TYPE="cpio"
				;;

			*)
				Usage "Error: unrecognized snapshot type"
				;;
		esac

		#if [ -d
		#if Is_same_mount
	fi

	# check vars
	if [ ! -d "${COW}" ]
	then
		Usage "Error: ${COW} is not a directory"
	fi

	Mount_device ${DEV}
}

Clean ()
{
	if [ -n "${DEV}" ]
	then
		umount "${MOUNTP}"
		rmdir "${MOUNTP}"
		#rm
	fi
}

Main ()
{
	Parse_args "${@}"
	Defaults
	Do_snapshot
	Clean
}

Main "${@}"