#!/bin/bash
# -----------------------------------------------------------------------------
#
# Copyright (c) 2011 - OpenSLX GmbH
#
# This program is free software distributed under the GPL version 2.
# See http://openslx.org/COPYING
#
# If you have any feedback please consult http://openslx.org/feedback and
# send your suggestions, praise, or complaints to feedback@openslx.org
#
# General information about OpenSLX can be found at http://openslx.org/
# -----------------------------------------------------------------------------
#
#	This file contains the functions needed to setup a target.
#	The main function is 'generate_target' which will go over all
#	activated modules (symlinks found under remote/targets/<target>)
#	and run the module-specific 'fetch_source', 'build' and 'post_copy'
#	functions of the modules.
#
#	The functions defined here are module-independent, meaning they
#	can process any module, as long as following requirements are met:
#
#		- Modules need to have a build-script and a config file,
#		  i.e. remote/module/kernel/module.build
#		  and  remote/module/kernel/module.conf
#		  as these will be read by 'process_module'.
#
#		- Modules need to generate a 'build'-directory in their
#		  own sub-directory (i.e. remote/modules/sshd/build/
#		  as 'copy_files_with_deps' will look for the files in
#		  that directory ONLY.
#
#		- Several information have to be set in the config file of
#		  a module:
#		    * REQUIRED_BINARIES - list of binaries
#		    * REQUIRED_FILES - list of regular files
#		    * REQUIRED_DIRECTORIES - list of directories
#		    * REQUIRED_SYSTEM_FILES - files to be copied directly from the system
#		    * REQUIRED_INSTALLED_PACKAGES - list of packages needed at build-time
#		    * REQUIRED_CONTENT_PACKAGES - list of packages where the contents are to be copied
#		    * (optional variables needed by the module-build-script)
#
#		  NOTE: REQUIRED_BINARIES, REQUIRED_FILES, REQUIRED_FILES will be ONLY looked
#		        for in the module's own build directory!
#
#	Optionally, a module can have a static data directory under
#	remote/modules/<module>/data which will be copied as is to the target build directory.
#
#	Moreover modules do not need to specify the dynamic dependencies of given binaries
#	as these will be determined automaticly by the helper function 'get_dynamic_dependencies'
# -----------------------------------------------------------------------------
#
MODE_DIR="${ROOT_DIR}/remote"
EXPORT_DIR="/export/build"
[ -z "$REMOTE_EXPORT_DIR" ] || EXPORT_DIR=$REMOTE_EXPORT_DIR
# Keep track of processed modules so we don't
# build a module multiple times when following dependencies
PROCESSED_MODULES=""

initial_checks () {
	get_kernel_version
	detect_distribution
}

#
# generic function to read the config file of the current $MODULE
#
read_config () {
	# unset previous variables from other config files
	for VARNAME in ${!REQUIRED_*}; do
		unset $VARNAME
	done

	local MODULE_CONFIG="${MODULE_DIR}/module.conf"

	# sanity checks
	[ ! -e "${MODULE_CONFIG}" ] && perror "Config for '$MODULE' not found."
	validate_config "$MODULE_CONFIG"
	# source the config file
	. "${MODULE_CONFIG}" || perror "Sourcing '${MODULE_CONFIG}' failed."
	# sanity checks - no distribution specific things in the global config
	local CHECK
	for CHECK in REQUIRED_CONTENT_PACKAGES REQUIRED_INSTALLED_PACKAGES; do
		[ -n "${!CHECK}" ] && perror "$CHECK is set in ${MODULE}.conf, but distribution specific config has to go to one of these files:\n$PRINT_SYS_VERSIONS"
	done
	local FILE
	for FILE in $SYS_VERSIONS; do
		if [ -e "${MODULE_CONFIG}.${FILE}" ]; then
			# a specific tool.conf seems to exist, use it to override/extend certain vars
			validate_config "${MODULE_CONFIG}.${FILE}"
			. "${MODULE_CONFIG}.${FILE}" || perror "Sourcing '${MODULE_CONFIG}.${FILE}' failed."
			pinfo "Sourced distribution specific config (${MODULE_CONFIG##*/}.${FILE})"
			return # end function
		fi
	done
	# reaching here means no specific config
	pinfo "Sourced general module config only (${MODULE_CONFIG##*/})"
}

validate_config () {
	local INVALID=$(grep -h -E -o '^\s*\w+=' "$1" | grep -v -E '^\s*REQUIRED_')
	[ -z "$INVALID" ] && return 0
	local i
	for i in $INVALID; do
		pwarning "Invalid variable $i"
	done
	perror "$1 contains invalid variables. All variables must start with REQUIRED_"
}

#
# generic function to read the build script of the current $MODULE
#
read_build () {
	local BUILD_SCRIPT="${MODULE_DIR}/module.build"

	[ ! -e "${BUILD_SCRIPT}" ] && perror "Build script for specified tool not found."

	. "${BUILD_SCRIPT}" || perror "Sourcing '${BUILD_SCRIPT}' failed."
}

export_builds() {
	[ ! -d "${MODE_DIR}/builds" ] && perror "No ${MODE_DIR}/builds, nothing to export."
	if mount|grep -q ${MODE_DIR}/builds; then
		pwarning "${MODE_DIR}/builds already exported! Ignoring..."
		return 1;
	fi
	pinfo "Mounting ${MODE_DIR}/builds to ${EXPORT_DIR}."
	pinfo "This will make the local builds syncable from another machine."
	[ ! -d "${EXPORT_DIR}" ] && mkdir -p "${EXPORT_DIR}"
	mount --bind ${MODE_DIR}/builds ${EXPORT_DIR} || perror "Failed to bind mount ${MODE_DIR}/builds to ${EXPORT_DIR}"
}

#
# main function which copies all files, directories, binaries and external libraries to TARGET_BUILD_DIR
# called after building the module
#
copy_files_with_deps () {

	[ ! -d "$MODULE_BUILD_DIR" ] && pinfo "No build directory found, skipping dependency copying" && return 0
	cd "$MODULE_BUILD_DIR"

	local COPYFILES_LIST="${TARGET_BUILD_DIR}/opt/openslx/.mltk/${MODULE}.copy_files_with_deps"
	rm -f -- "${COPYFILES_LIST}"

	# from REQUIRED_BINARIES - follow symlinks and ldd the file
	[ ! -z "${REQUIRED_BINARIES}" ] && pinfo "Gathering required binaries from config file..."
	local OPTIONAL
	for FILENAME in ${REQUIRED_BINARIES}; do
		if [[ "$FILENAME" == @* ]]; then
			OPTIONAL="yes"
			FILENAME=$(echo "$FILENAME" | cut -c 2- )
		else
			OPTIONAL="no"
		fi
		local FILE_CANDIDATES=$( find . -name "${FILENAME}" -a \( -type f -o -type l \) )
		local FINAL_LIST=""
		# Check result of find
		if [ "$(echo "$FILE_CANDIDATES" | wc -l)" -gt 1 ]; then
			# More than one match for binary
			pdebug "Candidates for $FILENAME are: $(echo $FILE_CANDIDATES)"
			for FILE in $FILE_CANDIDATES; do
				local TESTFILE="$(readlink -f "$FILE")"
				pdebug "  $FILE leads to $TESTFILE"
				[ -f "$TESTFILE" -a -x "$TESTFILE" ] && FINAL_LIST="$FINAL_LIST $FILE"
			done
			FINAL_LIST=$(trim "$FINAL_LIST")
			if [ -z "$FINAL_LIST" ]; then
				perror "\tNo binary found for ${FILENAME}. None of the candidates ($FILE_CANDIDATES) is executable."
			fi
			if [[ "$FINAL_LIST" == *" "* ]]; then
				pdebug "Found more than one match for required file '$FILENAME': $FINAL_LIST"
			else
				pdebug "\tFound ${FILENAME} at ${FILE}"
			fi
		elif [ "$OPTIONAL" == "no" -a -z "$FILE_CANDIDATES" ]; then
			# No candidate
			perror "Could not find required binary $FILENAME"
		else
			# One candidate
			local TESTFILE=$(readlink -f "$FILE_CANDIDATES")
			if [ -f "$TESTFILE" -a -x "$TESTFILE" ]; then
				FINAL_LIST=${FILE_CANDIDATES}
			elif [ "$OPTIONAL" = "no" ]; then
				perror "No executable regular file found for '$FILENAME' (potential match was $(echo $FILE_CANDIDATES))"
			fi
		fi
		for FILE in $FINAL_LIST; do
			pdebug "* $FILE"
			get_link_chain "${MODULE_BUILD_DIR}/${FILE}" "${MODULE_BUILD_DIR}" >> "${COPYFILES_LIST}"
			get_dynamic_dependencies -l "${MODULE_BUILD_DIR}" "${FILE}" >> "${COPYFILES_LIST}"
		done
	done

	# from REQUIRED_LIBRARIES - like binaries, follow symlinks and ldd, but also expand the lib-name
	# by looking for files named <libname>.so*
	[ ! -z "$REQUIRED_LIBRARIES" ] && pinfo "Gathering required libraries from config file..."
	for LIB in $REQUIRED_LIBRARIES; do
		FILE_CANDIDATES=$(find . -name "${LIB}.so*")
		[ -z "$FILE_CANDIDATES" ] && perror "Cannot find required library $LIB"
		for LOCATION in $FILE_CANDIDATES; do
			pdebug "* $LOCATION"
			get_link_chain "${MODULE_BUILD_DIR}/${LOCATION}" "${MODULE_BUILD_DIR}"  >> "${COPYFILES_LIST}"
			get_dynamic_dependencies -l "${MODULE_BUILD_DIR}" "${LOCATION}" >> "${COPYFILES_LIST}"
		done
	done

	# from REQUIRED_DIRECTORIES - recursively copy given dirs, look for files that seem to be an elf
	# binary and do the symlink+ldd trick on them
	[ ! -z "${REQUIRED_DIRECTORIES}" ] && pinfo "Gathering required directories from config file..."
	local ENTRY=""
	for ENTRY in ${REQUIRED_DIRECTORIES}; do
		[[ "$ENTRY" == /* ]] || perror "All entries in REQUIRED_DIRECTORIES have to start with a slash '/', but $ENTRY does not!"
		[ -e "$ENTRY" -a ! -d "$ENTRY" ] && perror "$ENTRY is not a directory"
		pdebug "* $ENTRY"
		ENTRY=".${ENTRY}"
		echo "${ENTRY}" >> "${COPYFILES_LIST}"
		for BIN in $(find "${ENTRY}" -type f -a \( -executable -o -name '*.so*' \) -a -not -name '*.a'); do
			[ -f "$BIN" ] || continue
			#pdebug "\tSearching libs for ${BIN}..."
			get_link_chain "${MODULE_BUILD_DIR}/${BIN}" "${MODULE_BUILD_DIR}" >> "${COPYFILES_LIST}"
			get_dynamic_dependencies -l "${MODULE_BUILD_DIR}" "${BIN}" >> "${COPYFILES_LIST}"
		done
	done

	# from REQUIRED_FILES - these are assumed to be simple files, so only follow symlinks
	[ ! -z "${REQUIRED_FILES}" ] && pinfo "Gathering required files from config file..."
	for ENTRY in ${REQUIRED_FILES}; do
		get_link_chain "${MODULE_BUILD_DIR}/${ENTRY}" "${MODULE_BUILD_DIR}" >> "${COPYFILES_LIST}"
	done

	#copy to initramfsdir
	pdebug "File list generated at ${COPYFILES_LIST}."
	# empty?
	if [ ! -s "$COPYFILES_LIST" ]; then
		return
	fi
	# unchanged?
	local OLD="${COPYFILES_LIST}.old"
	if [ -s "$OLD" ] && diff "$OLD" "$COPYFILES_LIST"; then
		return
	fi
	local CLISTCOUNT=$(cat "$COPYFILES_LIST" | wc -l)
	pinfo "Copying $CLISTCOUNT files to '${TARGET_BUILD_DIR}'."
	tarcopy "$(sort -u "$COPYFILES_LIST")" "${TARGET_BUILD_DIR}"
	mv -f "$COPYFILES_LIST" "$OLD"
}

#
#
# If the system has no usr split, recreate the structure in the given
# directory, otherwise, do nothing
#
#
prepare_usr_split () {
	local DIR DEST
	local BASE=$1
	[ -z "$BASE" ] && perror "prepare_usr_split called with empty base dir"
	if [ "$USR_SPLIT" == "no" ]; then # no usr split, /bin /lib etc are symlinks
		for DIR in lib lib32 lib64 bin sbin; do
			[ -L "/${DIR}" ] || continue
			DEST=$(readlink "/${DIR}")
			if [ ! -L "/${DEST}" ]; then
				mkdir -p "${BASE}/${DEST}" || perror "Could not create '${BASE}/${DEST}'"
			fi
			[ -L "${BASE}/${DIR}" ] || ln -s "${DEST}" "${BASE}/${DIR}" || perror "Could not symlink '${BASE}/${DIR}' to '${DEST}'"
		done
	fi
}

#
#
# main public function. Requires the TARGET to be given as argument.
# this will simply go over all the modules as found in the remote/target/<TARGET>
# and run following functions:
#
#
generate_target() {

	initial_checks

	TARGET=$1 && shift
	TARGET_DIR="${MODE_DIR}/targets/${TARGET}"
	TARGET_BUILD_DIR="${MODE_DIR}/builds/${TARGET}"
	[ -e "${ROOT_DIR}/logs/${TARGET}.size" ] && . "${ROOT_DIR}/logs/${TARGET}.size" || echo "declare -A BUILD_SIZE" >> "${ROOT_DIR}/logs/${TARGET}.size"

	[ -d "$TARGET_DIR" ] || perror "Given target directory does not exist: $TARGET_DIR"

	[[ "$TARGET" == "builds" || "$TARGET" == "modules" ]] && \
		perror "Target directory cannot be named 'builds' or 'modules'."

	pdebug "Generating '$TARGET_BUILD_DIR' for '$TARGET'"
	mkdir -p "$TARGET_BUILD_DIR" || perror "Failed to create $TARGET_BUILD_DIR"
	prepare_usr_split "${TARGET_BUILD_DIR}"

	# if no arguments assume all.
	if [ "x$1" = "x" -o "x$1" = "xall" ]; then
		MODULES=$(ls ${TARGET_DIR})
		set -- $MODULES
	else
		# tools = arguments given
		MODULES=$@
	fi

	pinfo "Activated modules in '${TARGET}':"
	pinfo "\t$(echo ${MODULES})"

	# we need a bit of special logic for kernel specifically
	# to check if the built version is corresponding to the
	# current kernel version. If not we had a kernel update
	# and need to tell the user
	if [[ -e "${TARGET_DIR}/kernel" ]]; then
		# if so, check what kernels have been built
		if [ -e "${TARGET_DIR}/kernel/ksrc/KVERSION" ]; then
			local BUILT_KERNEL_VERSION=$(cat "${TARGET_DIR}/kernel/ksrc/KVERSION")
			if [[ "${BUILT_KERNEL_VERSION}" != "${SYSTEM_KERNEL_LONG}" ]]; then
				pinfo "The built kernel (${BUILT_KERNEL_VERSION}) is older than the running one (${SYSTEM_KERNEL_LONG})!"
				# cleaning the module is enough as it forces to rebuild.
				[[ "${AUTO_UPDATE_KERNEL}" == 1 ]] && pinfo "Auto-Udpate Kernel..." && clean_kernel_module --force
			fi
		elif [ -e "${TARGET_DIR}/kernel/ksrc" ]; then
			# check if ksrc is there, since that would be problematic
			pwarning "${TARGET_DIR}/kernel/ksrc exists, but KVERSION is not found!"
			pwarning "Kernel was probably built with an older version of mltk."
			pwarning "If errors arise, either write your KVERSION manually or clean the kernel."
		fi
	fi

	# copy basic libs
	pinfo "Copying libc and ld-linux used by ${SHELL}"
	tarcopy "$(list_basic_libs)" "${TARGET_BUILD_DIR}"

	# now iterate over given tools and copy them
	while (( "$#" )); do
		process_module "$1"
		shift
	done

	post_process_target

	pinfo "Target completed. Total size: $(du -bsh "${TARGET_BUILD_DIR}" | awk 'END {print $1}')"
	TOOL_STR=""
}

process_module() {
	# Parse arguments
	[ "$#" -lt "1" ] && perror "process_module: want >= 1 param."
	if [ "x$1" = "x--dep-of" ]; then
		shift
		local DEPOF=" $1"
		shift
	else
		local DEPOF=""
	fi
	local MODULE="$1"
	[ -z "$MODULE" ] && perror "No module given when calling process_module"
	[[ "$PROCESSED_MODULES" == *"!${MODULE}!"* ]] && return # Already processed this module
	# Set up dirs ans variables
	PROCESSED_MODULES="${PROCESSED_MODULES}!${MODULE}!"
	local MODULE_DIR="${TARGET_DIR}/${MODULE}"
	local MODULE_BUILD_DIR="${MODULE_DIR}/build"
	local TOOL_STR="[${MODULE}]"
	local SOURCE_FLAG="$MODULE_BUILD_DIR/fetched_source.flag"
	local BUILD_FLAG="$MODULE_BUILD_DIR/build_complete.flag"
	local MD5FILE="${TARGET_BUILD_DIR}/opt/openslx/.mltk/${MODULE}.md5"
	mkdir -p "${TARGET_BUILD_DIR}/opt/openslx/.mltk"
	if [ ! -d "${MODULE_DIR}" ]; then
		if [ -z "$DEPOF" ]; then
			perror "Module directory for '$MODULE' not found in ${TAREGET_DIR}"
		fi
		perror "Module directory for '$MODULE' not found in ${TARGET_DIR} (is a dependency of${DEPOF})"
		return
	fi
	cd "${MODULE_DIR}" || perror "Module dir '${MODULE_DIR}' seems to exist, but cd to it failed."
	# Simple check for modified .build / .config, in which case we'll run a module clean first
	if [ -f "$MD5FILE" ]; then
		if ! md5sum --check "$MD5FILE"; then
			# Mismatch
			if [ "x$MODULE" = "xkernel" ]; then
				pwarning " ** Kernel .build/.config changed, but won't autoclean."
				pwarning " ** Check if cleaning should be done and use '-c kernel'"
			else
				pwarning "Module's .build/.config has changed, rebuilding!"
				clean_module "$MODULE_DIR"
			fi
		elif [ ! -e "$SOURCE_FLAG" ] || [ ! -e "$BUILD_FLAG" ]; then
			# One of the flags is missing, in this case delete the .md5 file
			# which would prevent dependency copying etc. below
			rm -f -- "$MD5FILE"
		fi
	fi
	# Process module
	pdebug "## Reading config of $MODULE"
	read_config
	# Prepare build directory
	mkdir -p "${MODULE_BUILD_DIR}" || perror "Could not create build dir"
	prepare_usr_split "${MODULE_BUILD_DIR}"
	# Check if this module has a dependency that wasn't built yet:
	if [ ! -z "$REQUIRED_MODULES" ]; then
		pdebug "$MODULE depends on ${REQUIRED_MODULES}...."
		for DEP in $REQUIRED_MODULES; do
			process_module --dep-of "${MODULE}${DEPOF}" "$DEP"
		done
		# Read old config again, as it got overwritten by the deps
		cd "${MODULE_DIR}" || perror "Tool dir '${MODULE_DIR}' seems to exist, but cd to it failed (after building deps)."
		read_config
	fi
	[ -n "$DEPOF" ] && local DEPOF_STR="(dependency of${DEPOF})"
	pinfo ">>>>>>>>>>>>>>>>> Processing module [ $MODULE ] $DEPOF_STR"
	# Update size of target build dir
	if [ -d "${TARGET_BUILD_DIR}" ]; then
		TARGET_BUILD_SIZE=$(du -bc "${TARGET_BUILD_DIR}" | awk 'END {print $1}')
	else
		TARGET_BUILD_SIZE=0
	fi
	# Source .build script of module
	pdebug "## Reading .build of $MODULE"
	. "${MODE_DIR}/clean_module_funcs.inc" # Clean all hooks, in case the module doesn't define them all
	read_build # Read all the hooks from the module
	# Install module's dependencies
	pdebug "## Installing dependencies"
	cd "${MODULE_DIR}" || perror "cd to '${MODULE_DIR}' failed."
	install_dependencies
	# update kernel version variables before running a module, as the last one might have been the kernel...
	get_kernel_version
	# Execute load-hook before anything else
	module_load
	# Fetch source code
	if [ ! -e "$SOURCE_FLAG" ]; then
		pinfo "## Fetching source"
		fetch_source
		touch "$SOURCE_FLAG" || pwarning "Error setting source-flag"
	fi
	# Build
	if [ ! -e "$BUILD_FLAG" ]; then
		pinfo "## Building"
		cd "${MODULE_DIR}" || perror "cd to '${MODULE_DIR}' failed."
		build # calls perror if something fails, no need to do that here
		strip_recursive "$MODULE_BUILD_DIR"
		touch "$BUILD_FLAG" || pwarning "Error setting built-flag"
	fi
	# Remove *.la files as they might confuse libtool/linker of other tool packages
	[ -d "${MODULE_BUILD_DIR}" ] && find "${MODULE_BUILD_DIR}" -name '*.la' -exec rm -f {} \;
	# Only copy stuff from system or build dir if md5s didn't change
	if [ ! -f "$MD5FILE" ]; then
		pinfo "## Copying files with dependencies"
		cd "${MODULE_DIR}" || perror "cd to '${MODULE_DIR}' failed."
		copy_files_with_deps
		if [ -n "$REQUIRED_SYSTEM_FILES" ]; then
			pinfo "## Copying required system files" # REQUIRED_SYSTEM_FILES
			cd "${MODULE_DIR}" || perror "cd to '${MODULE_DIR}' failed."
			copy_system_files
		fi
	fi
	# Always copy static data
	if [ -d "${MODULE_DIR}/data" ]; then
		pinfo "## Copying static module files"
		copy_static_data
	fi
	# TODO: automatic copy of REQUIRED_CONTENT_PACKAGES
	pinfo "## Post copy"
	cd "${MODULE_DIR}" || perror "cd to '${MODULE_DIR}' failed."
	post_copy
	# Write new md5 file if not existent yet
	if [ ! -f "$MD5FILE" ]; then
		md5sum "$MODULE_DIR/module".* > "$MD5FILE" || perror "Could not create $MD5FILE"
	fi
	# Sanity checks
	[ -e "$TARGET_BUILD_DIR/var/run" -a ! -L "$TARGET_BUILD_DIR/var/run" ] && perror "Messup datected: $TARGET_BUILD_DIR/var/run exists and is not a symlink!"
	[ -e "$TARGET_BUILD_DIR/var/lock" -a ! -L "$TARGET_BUILD_DIR/var/lock" ] && perror "Messup datected: $TARGET_BUILD_DIR/var/lock exists and is not a symlink!"
	[ -n "$(ls -A "$TARGET_BUILD_DIR/run")" ] && perror "Messup detected: $TARGET_BUILD_DIR/run is not empty. You cannot place static files there, use /etc/tmpfiles.d instead!"
	# set MODULE_BUILD_SIZE
	calc_size
	pinfo "Module completed. Total size: ${MODULE_BUILD_SIZE}"
}

post_process_target() {
	local TOOL_STR="$TOOL_STR post_process_target:"

	# figure out all relevant ld-paths
	pinfo "Running ldconfig"
	cp -r -L /etc/ld.so.conf* "${TARGET_BUILD_DIR}/etc/"
	ldconfig -v -r "${TARGET_BUILD_DIR}"
}

clean_modules() {

	TARGET=$1
	shift
	TARGET_DIR="${MODE_DIR}/targets/${TARGET}"
	TARGET_BUILD_DIR="${MODE_DIR}/builds/${TARGET}"
	[ -d $TARGET_DIR ] || perror "Given target directory does not exist: $TARGET_DIR"

	if [ "x$1" = "x" -o "x$1" = "xall" ]; then
		if [ -e ${ROOT_DIR}/logs/${TARGET}.size ]; then
			rm "${ROOT_DIR}/logs/${TARGET}.size" || perror "Could not delete logs/${TARGET}.size"
		fi
		if [ -d ${TARGET_BUILD_DIR} ]; then
			pinfo "Cleaning '${TARGET_BUILD_DIR}'" \
				&& rm -rf "${TARGET_BUILD_DIR}"/* \
				|| perror "Error deleting $TARGET_BUILD_DIR"
		fi
		# exclude kernel on "all"
		set -- $(ls ${TARGET_DIR} | grep -vE "^kernel$")
	fi
	cd "$TARGET_DIR"

	while (( "$#" )); do
		clean_module "${TARGET_DIR}/$1"
		shift
	done
	cd - &> /dev/null

	# libck-connector cleanup
	rm -f "$TARGET_DIR/post-patch/ck-connector/libck-connector.so"
}

clean_module() {
	[ -z "$1" ] && perror "No module given on clean_module()"
	[ ! -d "$1" ] && perror "Module dir $1 doesn't exist!"
	local MODULE=$(basename "$1")
	# if kernel is to be cleaned, do it separately and return
	[ "x$MODULE" == "xkernel" ] && clean_kernel_module && return

	pinfo "Cleaning '$1'..."
	local MODULE_DIR="$1"
	rm -rf -- "${MODULE_DIR}/build" || perror "Could not delete build path"
	rm -rf -- "${MODULE_DIR}/src" || perror "Could not delete src path"
	rm -f -- "${MODULE_DIR}/list_dpkg_output" || perror "Could not delete list_dpkg_output"
	rm -f -- "${MODULE_DIR}/list_binaries_and_files" || perror "Could not delete list_binaries_and_files"
	rm -f -- "${TARGET_BUILD_DIR}/opt/openslx/.mltk/${MODULE}."* # no space here!
	# These are not in use anymore, but leave the cleanup here for upgraders
	rm -f -- "${MODULE_DIR}/.built"
	rm -f -- "${MODULE_DIR}/.fetched_source"
}

clean_kernel_module() {
	pinfo "Cleaning kernel module (including sources and compiled stuff)."
	cd "${TARGET_DIR}/kernel" || perror "Could not cd to ${TARGET_DIR}/kernel"
	if [ -e build ]; then
		rm -rf build || pwarning "Could not delete ${TARGET_DIR}/kernel/build"
	fi
	# clean any git repos in nonstandard dirs
	find . -maxdepth 1 -type d -name "linux-*" -exec rm -rf -- {} \;
	# Clean aufs repo
	find . -maxdepth 1 -type d -name "aufs*-*" -exec rm -rf -- {} \;
	# clean the config generated and flag files
	rm -f -- "openslx.config" ".fetched_source" ".built"
	if [ -L "ksrc" ]; then
		unlink "ksrc" || perror "Could not unlink ${TARGET_DIR}/kernel/ksrc."
	elif [ -d "ksrc" ]; then
		rm -rf -- "ksrc" || perror "Could not delete directory ${TARGET_DIR}/kernel/ksrc."
	fi
	pinfo "Done cleaning kernel."
}

# Recursively strip binaries and libraries in the given directory
strip_recursive() {
	local DIR="$1"
	[ -n "$DIR" -a -d "$DIR" ] || perror "strip_recursive(): No such directory: '$DIR'"
	# Will try to strip shell scripts too but shouldn't do any harm
	find "$DIR" -type f -a \( -executable -o -name "*.so*" \) -exec strip {} \; 2> /dev/null
}

# copies static data files from <MODULE>/data/ to <TARGET_BUILD_DIR>
copy_static_data() {
	[ ! -d "${MODULE_DIR}/data" ] && pinfo "${MODULE} has no static 'data' directory." && return
	cd "${MODULE_DIR}/data/" || perror "could not cd to '${MODULE_DIR}/data/'"
	tarcopy "$(find . -type f -o -type l)" "${TARGET_BUILD_DIR}"
	cd -
}

# Copies files with their absolute paths in $REQUIRED_SYSTEM_FILES to $TARGET_BUILD_DIR
copy_system_files() {
	[ ! -z "$REQUIRED_SYSTEM_FILES" ] && tarcopy "$REQUIRED_SYSTEM_FILES" "$TARGET_BUILD_DIR"
}

# Tries to calculate the size of modules - doesn't seem to work all the time
calc_size() {

	local CURRENT_BUILD_SIZE=$(du -bc "${TARGET_BUILD_DIR}" | awk 'END {print $1}')

	[ ! -z "${BUILD_SIZE[$MODULE]}" ] && local OLD_MODULE_SIZE=${BUILD_SIZE[$MODULE]} || local OLD_MODULE_SIZE=0
	local diff=$((CURRENT_BUILD_SIZE-TARGET_BUILD_SIZE+OLD_MODULE_SIZE))

	if [ -z "${BUILD_SIZE[$MODULE]}" ]; then 
		echo "BUILD_SIZE[$MODULE]=${diff}" >> "${ROOT_DIR}/logs/${TARGET}.size"
	else
		sed -i "s/^BUILD_SIZE\[${MODULE}\]=.*$/BUILD_SIZE\[${MODULE}\]=${diff}/g" "${ROOT_DIR}/logs/${TARGET}.size"
	fi
	
	MODULE_BUILD_SIZE=$(echo $diff | awk '{ sum=$1; hum[1024^3]="GB"; hum[1024^2]="MB"; hum[1024]="KB"; 
					for (x=1024^3; x>=1024; x/=1024){ 
        					if (sum>=x) { printf "%.2f %s\n",sum/x,hum[x]; break }
					}
				}')
}