#!/bin/sh
# $Id$
#
# this script does EVERYTHING
# all other scripts are only frontends :)
#
# called by:
#	- some rc-scripts
#	- the web frontend cgi
#

set -eu

# parse config file
. /etc/cryptobox/cryptobox.conf

## configuration
CONFIG_MARKER="$CONFIG_DIR/cryptobox.marker"
CERT_TEMP=/tmp/stunnel.pem

#####

function log_msg()
{
	# the log file is not writable during boot - try before writing ...
	[ -w "$LOG_FILE" ] || return 0
	echo >>"$LOG_FILE"
	echo "##### `date` #####" >>"$LOG_FILE"
	echo "$1" >>"$LOG_FILE"
}


function error_msg()
# parameters: ExitCode ErrorMessage
{
	echo "[`date`] - $2" | tee -a "$LOG_FILE" >&2
	# print the execution stack - not usable with busybox
	#caller | sed 's/^/\t/' >&2
	exit "$1"
}


function initial_checks()
# Parameter: device
{
	local device="$1"
	[ ! -b "$device" ] && log_msg "blockdevice $device does not exist" && return 1
	[ ! -x "$WIPE" ] && log_msg "$WIPE not found" && return 1
	[ ! -x "$SFDISK" ] && log_msg "$SFDISK not found" && return 1
	for a in $ALGO $HASH
		do	grep -q "^name *: $a$" /proc/crypto || modprobe "$a"
			grep -q "^name *: $a$" /proc/crypto || { log_msg "$a is not supported by kernel" && return 1; }
	  done
	log_msg "inital checks successful"
	return 0
}


function create_partitions()
# Parameter: device
{
	local device="$1"
	# first partition size is 1 sector, second goes til end
	# sfdisk -n doesn't actually write (for testing purpose)
	echo -e "0,1,L \n,,L\n" | $SFDISK "$device"
}


function config_set_value()
# parameters: SettingName SettingValue
{
	mount -o rw,remount "$CONFIG_DIR"
	echo -n "$2" > "$CONFIG_DIR/$1"
	mount -o ro,remount "$CONFIG_DIR"
}


function config_get_value()
# parameters: SettingName
{
	# use mounted config, if it exists - otherwise use defaults
	local conf_dir
	if is_config_mounted
		then	conf_dir=$CONFIG_DIR
		else	conf_dir=$CONFIG_DEFAULTS_DIR
	  fi
	[ -z "$1" ] && error_msg 1 "empty setting name"
	[ ! -e "$conf_dir/$1" ] && error_msg 2 "unknown configuration value ($1)"
	# remove trailing line break
	echo -n $(cat "$conf_dir/$1")
}


function create_config()
# Parameter: device
{
	local device="${1}1"
	log_msg "Creating config filesystem ..."
	# filter output through 'tr' to replace tabs
	$MKFS_CONFIG "$device" | tr '\010' ' '
	# mount the config partition rw
	log_msg "Mounting config partition ..."
	mount "$device" "$CONFIG_DIR"
	# create a marker to recognize a cryptobox partition
	date -I >"$CONFIG_MARKER" 
	log_msg "Copying configuration defaults ..."
	cp -a "$CONFIG_DEFAULTS_DIR/." "$CONFIG_DIR"

	log_msg "Copying temporary cerificate file to config filesystem ..."
	# beware: the temp file should always be there - even after reboot - see "mount_config"
	cp -p "$CERT_TEMP" "$CERT_FILE"

	log_msg "Setting inital values ..."
	# beware: config_set_value remounts the config partition read-only
	config_set_value "device" "$1"
	config_set_value "ip" "$(get_current_ip)"

	# reinitialise configuration
	log_msg "Unmounting config partition ..."
	umount "$CONFIG_DIR"
	log_msg "Reload configuration ..."
	mount_config
}


function get_current_ip()
# not necessarily the same as configured (necessary for validation)
{
	# filter the output of ifconfig and remove trailing line break
	echo -n $(ifconfig $NET_IFACE | grep "inet" | cut -d ":" -f2 | cut -d " " -f1)
}


function create_crypto()
# Parameter: device
{
	local device="$1"
	# passphrase may be passed via command line
	$CRYPTSETUP -h "$HASH" -c "$ALGO" create "`basename $CRYPTMAPPER_DEV`" "${device}2"
}


function mkfs_crypto()
# split from create_crypto to allow background execution via web interface
{
	local device=$(find_harddisk)

	# flood the crypto partition with noise
	# writing to the real partition is faster
	# TODO: this takes _much_ too long - maybe add a "secure wipe" switch to the interface?
	#dd if=/dev/urandom of="${device}2" bs=512

	# filter output through 'tr' to replace tabs
	$MKFS_DATA "$CRYPTMAPPER_DEV" | tr '\0101' ' '
}


function config_mount_test()
# Parameter: device
{
	local device="${1}"
	local STATUS=0
	mount "${device}1" "$CONFIG_DIR" &>/dev/null || true
	is_config_mounted && STATUS=1
	umount "$CONFIG_DIR" &>/dev/null || true
	# return code is the result of this expression
	[ 1 -eq "$STATUS" ] && return 0
	return 1
}


function is_config_mounted()
{
	mount | grep -q " ${CONFIG_DIR} " && [ -f "$CONFIG_MARKER" ]
}


function is_crypto_mounted()
{
	mount | grep -q " ${CRYPTO_DIR} "
}


function is_init_running()
{
	check_at_command_queue " box-init-bg"
}


# check if a specified command is in an at-queue
# Parameter: a regular expression of the commandline
# Return: the command is part of an at-queue (0) or not (1)
function check_at_command_queue()
{
	# 1) get the available job numbers
	# 2) remove empty lines (especially the last one)
	# 3) check every associated command for the regexp
	at -l | cut -f 1 | while read jobnum
	  do	at -c $jobnum | sed '/^$/d' | tail -1
	 done | grep -q "$1"
}


function find_harddisk()
# look for the harddisk to be partitioned
{
	local dev=$(
		if is_config_mounted
		  then	config_get_value "device"
		  else	for a in $SCAN_DEVICES
			do	grep -q " `basename $a`$" /proc/partitions && echo "$a" && break
			    done
		fi )
	[ -z "$dev" ] && echo "no valid partition for initialisation found!" >>"$LOG_FILE"
	echo -n "$dev"
}


function mount_config()
{
	is_config_mounted && error_msg 3 "configuration directory ($CONFIG_DIR) is already mounted!"
	local device=$(
	    for a in $SCAN_DEVICES
		do	log_msg "Trying to load configuration from $a ..."
			config_mount_test "$a" && echo "$a" && break
		  done )
	if [ -n "$device" ] && mount "${device}1" "$CONFIG_DIR"
		then	log_msg "configuraton found on $device"
			config_set_value "device" "$device"
			# copy certificate to /tmp in case of re-initialization
			# /tmp should be writable, so tmpfs has to be mounted before (/etc/rcS.d)
			cp "$CERT_FILE" "$CERT_TEMP"
			return 0
		else	log_msg "failed to locate harddisk"
			return 1
	fi
}


function mount_crypto()
{
	is_crypto_mounted && echo "Das Crypto-Dateisystem ist bereits aktiv!" && return
	local device=`find_harddisk`
	[ -z "$device" ] && error_msg 4 'no valid harddisk found!'
	# passphrase is read from stdin
	log_msg "Mounting crypto partition ..."
	$CRYPTSETUP -h "$HASH" -c "$ALGO" create "`basename $CRYPTMAPPER_DEV`" "${device}2"
	if mount "$CRYPTMAPPER_DEV" "$CRYPTO_DIR"
		then	log_msg "Mount succeded - now starting samba ..."
			/etc/init.d/samba start
		else	log_msg "Mount failed - removing dev-mapper ..."
			dmsetup remove $(basename $CRYPTMAPPER_DEV)
			return 1
	fi
}


function umount_crypto()
{
	# do not break on error
	set +e
	if ps -e | grep -q " [sn]mbd$" 
		then	log_msg "Stopping samba ..."
			/etc/init.d/samba stop
			ps -e | grep -q " smbd$" && killall smbd
			ps -e | grep -q " nmbd$" && killall nmbd
			ps -e | grep -q " smbd$" && killall -9 smbd
			ps -e | grep -q " nmbd$" && killall -9 nmbd
	  fi
	if mount | grep -q " $CRYPTO_DIR "
		then	log_msg "Unmounting crypto partition ..."
			umount "$CRYPTO_DIR"
	  fi
	if [ -e "$CRYPTMAPPER_DEV" ]
		then	log_msg "Removing dev-mapper ..."
			$CRYPTSETUP remove $(basename $CRYPTMAPPER_DEV)
	  fi
	set -e
}

		
function init_cryptobox_part1()
# this is only the first part of initialisation that takes no time - good for a smooth web interface
{
	local device=$(find_harddisk)
	[ -z "$device" ] && log_msg 'no valid harddisk found!' && return 1
	(
		log_msg "Initializing crypto partition on $device ..."
		umount_crypto || true
		mount | grep -q " $CONFIG_DIR " && umount "$CONFIG_DIR" || true
		initial_checks "$device" || return 1
		create_partitions "$device"
		create_config "$device"
	) >>"$LOG_FILE" 2>&1
	# the output of create_crypto may NOT be redirected - this would prevent cryptsetup from
	# reading the passphrase from stdin
	log_msg "Creating the crypto partition ..."
	create_crypto "$device"
}


function init_cryptobox_part2()
# some things to be done in the background
# these are the final steps of initialisation
# the uid must be changed initially, therfore it needs to be mounted
{
	mkfs_crypto
	mount "$CRYPTMAPPER_DEV" "$CRYPTO_DIR"
	chown $SAMBA_USER "$CRYPTO_DIR"
	umount_crypto
}


function init_cryptobox_complete()
{
	init_cryptobox_part1
	init_cryptobox_part2
}

### main ###

# set PATH because thttpd removes /sbin and /usr/sbin for cgis
export PATH=/usr/sbin:/usr/bin:/sbin:/bin


ACTION=help
[ $# -gt 0 ] && ACTION="$1"

case "$ACTION" in
	config-up )
		if mount_config
		  then	echo "Cryptobox configuration successfully loaded"
		  else	error_msg 3 "Could not find a configuration partition!"
		 fi
		;;
	config-down )
		umount "$CONFIG_DIR" || error_msg 4 "Could not unmount configuration partition"
		;;
	network-up )
		kudzu -s -q --class network
		conf_ip=$(config_get_value "ip")
		ifconfig $NET_IFACE "$conf_ip"
		log_msg "Configured $NET_IFACE for $conf_ip ..."
		echo "Configured network interface for $NET_IFACE: $conf_ip"
		log_msg "Starting the firewall ..."
		"$FIREWALL_SCRIPT" start
		# start stunnel
		if [ -f "$CERT_FILE" ] 
		   then	USE_CERT=$CERT_FILE
		   else USE_CERT=$CERT_TEMP
			$MAKE_CERT_SCRIPT "$CERT_TEMP" >>"$LOG_FILE" 2>&1
		  fi
		log_msg "Starting stunnel ..."
		stunnel -p "$USE_CERT" -r localhost:80 -d 443 \
			|| echo "$USE_CERT not found - not starting stunnel"
		# this ping allows other hosts to get the IP of
		# the box, in case of misconfiguration
		ping -b -c 1 $(ifconfig $NET_IFACE | grep Bcast | cut -d ":" -f 3 | cut -d " " -f 1) &>/dev/null
		;;
	network-down )
		log_msg "Stopping the firewall ..."
		"$FIREWALL_SCRIPT" stop
		log_msg "Stopping stunnel ..."
		killall stunnel
		log_msg "Shutting the network interface down ..."
		ifconfig $NET_IFACE down
		;;
	services-up )
		# is something special necessary?
		;;
	services-down )
		/etc/init.d/samba stop
		/etc/init.d/thttpd stop
		;;
	crypto-up )
		mount_crypto
		;;
	crypto-down )
		umount_crypto
		;;
	box-init )
		# do complete initialization
		"$0" box-init-fg
		# the background part will recall itself as an at-command
		"$0" box-init-bg
		;;
	box-init-fg )
		# only partitioning and configuration
		# this is nice for the web interface, as it is fast
		# output redirection does not work, as it prevents cryptsetup from asking
		# for a password
		init_cryptobox_part1
		;;
	box-init-bg )
		# do it in the background to provide a smoother web interface
		# messages and errors get written to $LOG_FILE

		# make sure, that this is always called via 'at':
		if check_at_command_queue " box-init-bg"
		  then	init_cryptobox_part2 </dev/null >>"$LOG_FILE" 2>&1
		  else	echo -n "'$0' box-init-bg" | at now
		 fi
		;;
	is_crypto_mounted )
		is_crypto_mounted
		;;
	is_config_mounted )
		is_config_mounted
		;;
	is_init_running )
		is_init_running
		;;
	is_harddisk_available )
		[ -z "$(find_harddisk)" ] && exit 1
		exit 0
		;;
	update_ip_address )
		# reconfigure the network interface to a new IP address
		# wait for 5 seconds to finish present http requests
		echo -n "sleep 5; ifconfig $NET_IFACE `config_get_value ip`" | at now
		;;
	get_current_ip )
		get_current_ip
		;;
	set_config )
		[ $# -ne 3 ] && error_msg 7 "'set_config' requires two parameters"
		config_set_value "$2" "$3"
		;;
	get_config )
		[ $# -ne 2 ] && error_msg 6 "'get_config' requires exactly one parameter"
		config_get_value "$2"
		;;
	diskinfo )
		$SFDISK -L -q -l `find_harddisk`
		;;
	poweroff )
		is_crypto_mounted && umount_crypto
		log_msg "Turning off the CryptoBox ..."
		echo "poweroff" | at now
		;;
	reboot )
		is_crypto_mounted && umount_crypto
		log_msg "Rebooting the CryptoBox ..."
		echo "reboot" | at now
		;;
	clean )
		# only for development
		log_msg "Cleaning the CryptoBox ..."
		device=$(find_harddisk)
		$0 crypto-down
		$0 config-down
		# TODO: test this!
		echo -e ";\n;\n;\n;\n" | $SFDISK "$device"
		;;
	* )
		echo "Syntax: `basename $0` ACTION [PARAMS]"
		echo "  config-up		- scan for configuration partition and mount it"
		echo "  config-down		- unmount configuration partition"
		echo "  network-up		- enable network interface"
		echo "  network-down		- disable network interface"
		echo "  services-up		- run some cryptobox specific daemons"
		echo "  services-down		- stop some cryptobox specific daemons"
		echo "  crypto-up		- mount crypto partition and start samba"
		echo "  crypto-down		- unmount crypto partition and stop samba"
		echo "  box-init		- initialize cryptobox (ALL data is LOST)"
		echo "  box-init-fg		- the first part of initialization"
		echo "  box-init-bg		- the last part of initialization (background)"
		echo "  is_crypto_mounted	- check, if crypto partition is mounted"
		echo "  is_config_mounted	- check, if configuration partition is mounted"
		echo "  is_init_running	- check, if initialization is ongoing"
		echo "  is_harddisk_available	- check, if there is a usable harddisk"
		echo "  get_current_ip	- get the current IP of the network interface"
		echo "  update_ip_address	- update the network interface after reconfiguration"
		echo "  set_config NAME VALUE	- change a configuration setting"
		echo "  get_config NAME	- retrieve a configuration setting"
		echo "  diskinfo		- show the partition table of the harddisk"
		echo "  poweroff		- shutdown the cryptobox"
		echo "  clean		- remove all partitions [only for development]"
		echo "  reboot		- reboot the cryptobox"
		echo
		;;
  esac