#!/bin/sh
#
#  Copyright (c) 02005 sense.lab <senselab@systemausfall.org>
#
#  License:  This script is distributed under the terms of version 2
#            of the GNU GPL. See the LICENSE file included with the package.
#
# $Id$
#
# this script is responsible for all dangerous actions, that require root privileges
# every action should be checked at least TWICE a day for open holes :)
# usually will get call via sudo
#
# called by:
#	- cbox-manage.sh
#

set -eu

[ "$(id -u)" -ne 0 ] && echo "$(basename $0) - only root may call this script" >&2 && exit 100

# read the default setting file, if it exists
[ -e /etc/default/cryptobox ] && . /etc/default/cryptobox

# set CONF_FILE to default value, if not configured in /etc/default/cryptobox
CONF_FILE=${CONF_FILE:-/etc/cryptobox/cryptobox.conf}
# parse config file
. "$CONF_FILE"


############ some useful functions ###############

# check if the given device is part of the SCAN_DEVICE list
# every entry in SCAN_DEVICES is matched as "^/dev/${SCAN_DEVICE}[0-9]*$" against
# the given device
# other devices may not be touched
function is_device_allowed()
# parameter: device
{
	for a in $SCAN_DEVICES
		do	[[ "$1" =~ "^/dev/${a}[0-9]*$" ]] && return 0
	  done
	return 1
}


function get_device_name()
# return the uuid of the device
# if there is no uuid, then the device name is "flattened" and returned
# ignore volume-id as it may be non-unique
{
	local UUID=
	# check for luksUUID or ext2/3-uuid
	if is_luks_device "$1"
		then	UUID=$("$CRYPTSETUP" luksUUID "$1")
		else	[ -n "$(which dumpe2fs)" ] && UUID=$(dumpe2fs -h "$1" 2>/dev/null | grep "UUID" | cut -d ":" -f 2 | sed "s/ *//g")
	  fi
	# if there is no valid UUUD, then take the flattened device name
	is_uuid_valid "$UUID" || UUID=${1//\//_}
	echo "$UUID"
}


function is_uuid_valid()
# every devmapper name should look like a UUID
{
	local hex=[0-9a-f]
	[[ "$1" =~ "^$hex\{8\}-$hex\{4\}-$hex\{4\}-$hex\{4\}-$hex\{12\}$" ]]
}


function error_msg()
# parameter ExitCode ErrorMessage
{
	echo "CBOX-ERROR: [$(basename $0) - $ACTION] - $2" >&2
	exit $1
}


function partition_device()
# parameter: device sfdisk_layout_setup
# e.g.: /dev/hda "0,1,L \n,,L\n"
{
	# TODO: allow different layouts
	# TODO: skip config partition if a configuration is already active
	# sfdisk -n doesn't actually write (for testing purpose)
	if echo -e "$2" | "$SFDISK" -n "$1"
		then	echo -e "$2" | "$SFDISK" "$1" || return 1
		else	return 2
	  fi
	true
}


function is_luks_device()
# parameter: device
{
	"$CRYPTSETUP" isLuks "$1"
}


################ main ####################

ACTION=unknown
[ $# -gt 0 ] && ACTION=$1 && shift


case "$ACTION" in
	partition_disk )
		[ $# -ne 2 ] && error_msg 1 "wrong number of parameters"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		partition_device "$1" "$2" || \
			error_msg 2 "failed to create new partition table on device $1"
		;;
	mount )
		# parameters: device
		# returns the relative name of the mointpoint for success
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		name=$(get_device_name "$1")
		mountpoint -q "$MNT_PARENT/$name" && \
			error_msg 5 "a device with the same name ($name) is already mounted"
		mkdir -p "$MNT_PARENT/$name"
		if is_luks_device "$1"
		   then	"$CRYPTSETUP" luksOpen "$1" "$name" || \
					error_msg 6 "could not open encrypted device $1"
				if mount "$DEV_MAPPER_DIR/$name" "$MNT_PARENT/$name"
					then	true
					else	"$CRYPTSETUP" luksClose "$name" || true
							error_msg 7 "wrong password for $1 supplied"
				  fi
		   else	mount "$1" "$MNT_PARENT/$name" || \
					error_msg 8 "invalid filesystem on device $1"
		  fi
		# just in case, that there is no ext2/3 filesystem:
		# set uid option (will fail silently for ext2/3)
		mount -o remount,uid="$FILE_USER" "$MNT_PARENT/$name" 2>/dev/null || true
		# adapt top-level permission to current setup - again: may fail silently
		chown "$FILE_USER" "$MNT_PARENT/$name" 2>/dev/null || true
		true
		;;
	umount )
		#parameter: name (relative mountpoint)
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		is_uuid_valid "$1" || [[ "$1" =~ "^[_a-z0-9]*$" ]] || \
			error_msg 4 "invalid UUID ($1)"
		mountpoint -q "$MNT_PARENT/$1" || \
			error_msg 9 "the device with the UUID ($1) is not mounted"
		# try to unmount - continue even on errors
		umount "$MNT_PARENT/$1" || \
			error_msg 0 "unmount of device $1 failed - device is busy"
		# remove (if necessary) the dev mapping
		[ -e "$DEV_MAPPER_DIR/$1" ] && "$CRYPTSETUP" luksClose "$1" || \
			error_msg 11 "could not remove the device mapper for device $1"
		# try to remove the mountpoint - a failure is not important
		rmdir "$MNT_PARENT/$1" || true
		# set exitcode
		mountpoint -q "$MNT_PARENT/$1" && exit 1
		exit 0
		;;
	create_crypto )
		# parameter: device
		# the passphrase is expected on stdin
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		# read the passphrase from stdin
		key=$(cat -)
		# the iter-time is in milliseconds - keep it low for fast mounting
		echo "$key" | \
			"$CRYPTSETUP" --cipher "$DEFAULT_CIPHER" --iter-time 2000 luksFormat "$1" || \
			error_msg 11 "failed to create the encrypted partition"
		name=$(get_device_name "$1")
		echo "$key" | "$CRYPTSETUP" luksOpen "$1" "$name" || \
			error_msg 12 "failed to open the encrypted partition"
		# silent output from mkfs.ext3
		"$MKFS_DATA" -q "$DEV_MAPPER_DIR/$name" || \
			error_msg 13 "failed to create the encrypted filesystem"
		"$CRYPTSETUP" luksClose "$name" || \
			error_msg 14 "failed to close the encrypted mapped device"
		;;
	get_device_name )
		# parameter: device
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		get_device_name "$1"
		;;
	mount_config )
		# parameter: device
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		[ "$USE_SEPERATE_CONFIG_DIR" != "1" ] && \
			error_msg 19 "I am configured to work without a seperate config partition (see $CONF_FILE)"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		mountpoint -q "$CONFIG_DIR" && \
			error_msg 0 "the configuration partition is already mounted"
		"$MKFS_CONFIG" -q "$1" || \
			error_msg 20 "failed to create config partition filesystem"
		;;
	mount_config )
		# parameter: device
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		[ "$USE_SEPERATE_CONFIG_DIR" != "1" ] && \
			error_msg 19 "I am configured to work without a seperate config partition (see $CONF_FILE)"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		mountpoint -q "$CONFIG_DIR" && \
			error_msg 0 "the configuration partition is already mounted"
		mount "$1" "$CONFIG_DIR" || \
						error_msg 16 "failed to mount configuration partition"
		# chown to fix permissions - may fail for non-ext2/3 filesystems
		chown -R "$WEB_USER" "$CONFIG_DIR" || true
		mount -o remount,ro "$CONFIG_DIR" || \
			error_msg 18 "failed to remount configuration partition"
		true
		;;
	remount_config )
		# parameter: { ro | rw }
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		[ "$USE_SEPERATE_CONFIG_DIR" != "1" ] && \
			error_msg 19 "I am configured to work without a seperate config partition (see $CONF_FILE)"
		[[ "$1" =~ "^r[ow]$" ]] || error_msg 17 "only 'rw' and 'ro' are allowed"
		mount -o "remount,$1" "$CONFIG_DIR" || \
			error_msg 18 "failed to remount configuration partition"
		true
		;;
	umount_config )
		# no parameters
		[ $# -ne 0 ] && error_msg 1 "wrong number of parameters"
		[ "$USE_SEPERATE_CONFIG_DIR" != "1" ] && \
			error_msg 19 "I am configured to work without a seperate config partition (see $CONF_FILE)"
		mountpoint -q "$CONFIG_DIR" && umount "$CONFIG_DIR" || \
			error_msg 18 "failed to unmount configuration partition"
		;;
	is_config_partition )
		# parameter: device
		# returns exitcode 0 if the device contains a configuration
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		[ "$USE_SEPERATE_CONFIG_DIR" != "1" ] && \
			error_msg 19 "I am configured to work without a seperate config partition (see $CONF_FILE)"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		is_config=0
		tmp_dir=/tmp/$(basename $0)-$$-mnt
		mkdir -p "$tmp_dir"
		# error means "no config partition"
		if mount "$1" "$CONFIG_DIR"
			then	[ -e "$CONFIG_DIR/$CONFIG_MARKER" ] && is_config=1
					umount "$CONFIG_DIR" || \
						error_msg 14 "unable to unmount configation partition after probing"
		  fi
		rmdir "$tmp_dir" || true
		# return 0 if $device is a config partition
		[ "$is_config" -eq 1 ] && exit 0
		exit 1
		;;
	is_crypto_partition )
		# parameter: device
		# returns exitcode 0 if the device contains a luks header
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		is_luks_device "$1"
		;;
	is_data_partition )
		# parameter: device
		# returns exitcode 0 if the device contains a readable filesystem
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		status=0
		tmp_dir=/tmp/$(basename $0)-$$-mnt
		mkdir -p "$tmp_dir"
		if mount "$1" "$tmp_dir"
			then	[ ! -e "$tmp_dir/$CONFIG_MARKER" ] && status=1
					umount "$tmp_dir"
		  fi
		rmdir "$tmp_dir" || true
		[ "$status" -eq 1 ] && exit 0
		exit 1
		;;
	trash_device )
		# parameter: device
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		dd if=/dev/urandom of="$1" bs=512 count=1 2>/dev/null
		;;
	diskinfo )
		# parameter: device
		[ $# -ne 1 ] && error_msg 1 "wrong number of parameters"
		is_device_allowed "$1" || \
			error_msg 3 "this device ($1) is not listed in SCAN_DEVICES (see $CONF_FILE)"
		"$SFDISK" -L -q -l "$1"
		;;
	update_network )
		# parameter: none
		ip=
		# TODO: can we avoid to hard-code the filename ($CONFIG_DIR/ip) here?
		[ -e "$CONFIG_DIR/ip" ] && ip=$(<"$CONFIG_DIR/ip")
		[ -n "$z" ] && ifconfig "$NET_IFACE" "$ip"
		;;
	* )
		echo "Syntax: $(basename $0) ACTION PARAMETERS"
		echo '	partition_disk			$device	$disk_layout'
		echo '	get_device_name			$device'
		echo '	create_crypto			$device'
		echo '	mount				$device'
		echo '	umount				$name'
		echo '	create_config			$device'
		echo '	mount_config			$device'
		echo '	remount_config			{ ro | rw }'
		echo '	umount_config'
		echo '	is_config_partition		$device'
		echo '	is_plaindata_partition	$device'
		echo '	is_crypto_partition		$device'
		echo '	trash_device			$device'
		echo '	diskinfo			$device'
		echo '	update_network'
		echo '	help'
		echo
		[ "$ACTION" == "help" ] && exit 0
		# return error for any unknown/unspecified action
		exit 1
		;;
  esac