#!/bin/bash

#   FILE: mount.crypt -- mount a dm-crypt encrypted volume
# AUTHOR: W. Michael Petullo <mike@flyn.org>
#   DATE: 18 April 2004
# 
# Copyright (C) 2004 W. Michael Petullo <mike@flyn.org>
# All rights reserved.
# 
# 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

LOSETUP=/sbin/losetup
CRYPTSETUP=/bin/cryptsetup
MOUNT=/bin/mount

OPTIONS=""

USAGE="dev dir [-o options]

  -o options  set the mount options  [ $OUT ]"

_losetup() {
	DEVICE=$1
	LOOPDEV=0
	while [ $LOOPDEV -le 15 ]; do
		if $LOSETUP /dev/loop${LOOPDEV} $DEVICE 2> /dev/null; then
			echo /dev/loop${LOOPDEV}
			return 0
		fi
		LOOPDEV=$(($LOOPDEV + 1))
	done
	echo "${0##*/}: error setting up loop device for $DEVICE" >&2
	exit 1
}

while :;
	do case "$1" in
		-h | "-?" )	
			echo -e usage: ${0##*/} "$USAGE" >&2
			exit 1 ;;
		-?* )
			echo "${0##*/}: unrecognised option: $1" >&2
			exit 1 ;;
		* )
			break ;;
	esac
	shift
done

if [ -z "$1" ]; then
	echo "${0##*/}: device to mount not specified" >&2
fi

if [ ! -f "$1" ] && [ ! -b "$1" ]; then
        echo "${0##*/}: $1 is not a block device or file" >&2
	exit 1
fi

if [ ! -d "$2" ]; then
        echo "${0##*/}: $2 is not a directory" >&2
	exit 1
fi

OPTIONS="$4"
CIPHER=""
KEYSIZE=""
HASH=""
LOOP=false
MOUNTOPTIONS=""
IFS=","
for opt in $OPTIONS; do
	KEY=`echo $opt | awk -F = '{ print $1 }'`
	VAL=`echo $opt | awk -F = '{ print $2 }'`
	case $KEY in
		# FIXME: use cipher instead of encryption to avoid conflicting
		# with mount's built-in (cryptoloop) encryption argument.
		cipher )
			CIPHER="$VAL"
			;;
		keysize )
			KEYSIZE="$VAL"
			;;
		hash )
			HASH="$VAL"
			;;
		loop )
			LOOP=true
			;;
		* )
			if [ -z "$MOUNTOPTIONS" ]; then
				MOUNTOPTIONS="$opt"
			else
				IFS=""
				MOUNTOPTIONS="$MOUNTOPTIONS,$opt"
			fi
			;;
	esac
done

if [ x"${LOOP}" = xtrue ]; then
	DEVICE=`_losetup $1`
else
	DEVICE=$1
fi
# if loop device, make device mapper name based on file pointed to
if [ `echo $1 | grep '^/dev/loop'` ]; then
	DMDEVICE=`$LOSETUP $1 | egrep '(.+)' | awk '{print $3}' | sed 's/(//' | sed 's/)//'`
fi
# if not a loop device or previous command fails
if [ -z $DMDEVICE ]; then
	DMDEVICE=$1
fi
# FIXME: blind replacement of / with _ may be a bad idea.
DMDEVICE=`echo $DMDEVICE | sed 's/\//_/g'`

CIPHEROPT="aes"
if [ -n "$CIPHER" ]; then
	CIPHEROPT="$CIPHER"
fi

HASHOPT="ripemd160"
if [ -n "$HASH" ]; then
	HASHOPT="$HASH"
fi

KEYSIZEOPT="256"
if [ -n "$KEYSIZE" ]; then
	KEYSIZEOPT="$KEYSIZE"
fi

$CRYPTSETUP -c $CIPHEROPT -h $HASHOPT -s $KEYSIZEOPT create $DMDEVICE $DEVICE
if [ $? != 0 ]; then
	echo "${0##*/}: error creating $DMDEVICE" >&2
	[ x"$LOOP" = xtrue ] && $LOSETUP -d $DEVICE
	exit 1
fi

if [ -z "$MOUNTOPTIONS" ]; then
	# $2 might not exist as mount can try to read it from /etc/fstab
	$MOUNT /dev/mapper/$DMDEVICE $2
	if [ $? != 0 ]; then
		echo "${0##*/}: error mounting $DMDEVICE" >&2
		$CRYPTSETUP remove $DMDEVICE
		[ x"$LOOP" = xtrue ] && $LOSETUP -d $DEVICE
		exit 1
	fi
else
	$MOUNT -o $MOUNTOPTIONS /dev/mapper/$DMDEVICE $2
	if [ $? != 0 ]; then
		echo "${0##*/}: error mounting $DMDEVICE" >&2
		$CRYPTSETUP remove $DMDEVICE
		[ x"$LOOP" = xtrue ] && $LOSETUP -d $DEVICE
		exit 1
	fi
fi