#!/bin/bash
# Customized kernel from system: fetch Distro's kernel sources, patch configuration, recompile

# This overrides get_kernel_version from kernel.inc, so the variables will be set properly
get_kernel_version() {
	# Do not use MODULE_DIR here as this function might run when we process another module!
	[ -n "${TARGET_KERNEL_LONG}" ] && return 0
	[ ! -e "${ROOT_DIR}/tmp/work/kernel/ksrc/include/generated/utsrelease.h" ] && pinfo "No UTS information" && return 0
	# determine kernel version that will be running in the generated system

	# declare kernel version stuff
	declare -rg TARGET_KERNEL_LONG=$(grep 'UTS_RELEASE' "${ROOT_DIR}/tmp/work/kernel/ksrc/include/generated/utsrelease.h" | awk -F '"' '{print $2}')
	declare -rg TARGET_KERNEL_SHORT=$(echo "$TARGET_KERNEL_LONG" | grep -o -E '^[0-9\.]+')

	# declare path to kernel headers and modules/firmware
	declare -rg KERNEL_HEADERS_DIR="${ROOT_DIR}/tmp/work/kernel/ksrc"
	declare -rg KERNEL_BASE_DIR="${ROOT_DIR}/tmp/work/kernel/build"

	# print debug info
	pinfo "TARGET_KERNEL_LONG: '$TARGET_KERNEL_LONG'"
	pinfo "TARGET_KERNEL_SHORT: '$TARGET_KERNEL_SHORT'"
	pdebug "KERNEL_BASE_DIR: '$KERNEL_BASE_DIR'"
	pdebug "KERNEL_HEADERS_DIR: '$KERNEL_HEADERS_DIR'"
}

fetch_source() {
	pdebug "getting kernel sources via git ...."
	if grep -q -- "${REQUIRED_GIT}" "./ksrc/.git/config" && grep -q -- "v${REQUIRED_KERNEL}" "./ksrc/.git/config"; then
		pinfo "Trying to update existing clone"
		cde ksrc
		git pull || perror "Could not pull already checked out repo"
		cd ..
	else
		rm -rf "./ksrc"
		git clone --depth 1 "${REQUIRED_GIT}" -b "v${REQUIRED_KERNEL}"  ksrc || perror "Could not clone kernel git."
	fi
	if [ "$REMOTE_LOCAL_INSTALL" -eq 0 ]; then
		# check for aufs
		local RSL=$(find ksrc/ -type d -name aufs)
		if [ -z "$RSL" ]; then
			pinfo "aufs not found in kernel sources, patching it..."
			patch_aufs
		else
			pinfo "aufs detected in kernel source :)"
		fi
	fi
	# Other patches
	local patch
	cde "$MODULE_WORK_DIR/ksrc"
	for patch in "${MODULE_DIR}/patches/"*; do
		[ -f "$patch" ] || continue
		grep -q -F "$patch" "patches-done" && continue
		pinfo "Applying $(basename "$patch")"
		git apply < "$patch" || perror "Could not apply $patch"
		echo "$patch" >> "patches-done"
	done
	sed -i 's/batch_add(&cmds, 0xffff0000);/batch_add(\&cmds, 0xffff0000 | ((IS_IVB_GT1(i915) || IS_VALLEYVIEW(i915)) ? HIZ_RAW_STALL_OPT_DISABLE : 0));/' "drivers/gpu/drm/i915/gt/gen7_renderclear.c" || pwarning "Could not patch Ivybridge/Baytrail graphics."
	cd -
	# remember the current kernel version
	echo "${SYSTEM_KERNEL_LONG}" > ksrc/KVERSION
	# Fetch all the firmware
	if ! [ -s "./fw/Makefile" ]; then
		rm -rf -- "./fw"
		git clone "git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git" "./fw" || perror "Could not clone linux-firmware repo."
		rm -rf -- ./fw/LICENSE.* ./fw/*.txt
	fi
}

build() {
	local TARGET_CONFIG_FILE="openslx.config"
	rm -f "${TARGET_CONFIG_FILE}"
	# update config and copy to ksrc
	pinfo "Updating kernel config..."
	update_config
	cp "${TARGET_CONFIG_FILE}" "ksrc/.config"
	# make kernel with the new config
	cde ksrc
	pinfo "Preparing kernel for new config ('make oldconfig')."
	if [ "x$MLTK_QUIET" = "x1" ]; then
		make olddefconfig || perror "make oldconfig failed."
	else
		make oldconfig || perror "make oldconfig failed."
	fi

	pinfo "Compiling kernel... (this will take some time)"
	# explicitly state number of cores here, as MAKEFLAGS seems to be overridden
	# also pass CC if set by core/includes/system.inc
	make $MAKEFLAGS ${CC:+CC=${CC}} || perror "make failed."

	# install modules to build directory
	pinfo "Installing kernel modules..."
	if [ -d "${MODULE_BUILD_DIR}/lib/modules" ]; then
		rm -r "${MODULE_BUILD_DIR}/lib/modules" || pwarning "Could not clean old modules."
	fi
	make INSTALL_MOD_PATH="${MODULE_BUILD_DIR}" INSTALL_MOD_STRIP=1 modules_install || perror "make modules_install failed in ${MODULE_BUILD_DIR}."
	cd - 2> /dev/null

	# copy most recent firmware
	mkdir -p "${MODULE_BUILD_DIR}/lib/firmware"
	cp -r ./fw/* "${MODULE_BUILD_DIR}/lib/firmware/" || perror "Could not copy linux-firmware to '${MODULE_BUILD_DIR}/lib/firmware/'"

	# copy kernel to build
	cp ksrc/arch/x86/boot/bzImage "${MODULE_BUILD_DIR}/kernel"
	pinfo "Kernel was successfully built at ${MODULE_BUILD_DIR}/kernel"
	[ -z "${KERNEL_BUILD_DIR}" ] && KERNEL_BUILD_DIR="${MODULE_BUILD_DIR}"
}

post_copy() {
	:
}

# helper function to update the current kernel config with our parameters
update_config() {

	# first we need to update the current config
	local BASE_CONFIG_FILE="/boot/config-$(uname -r)"
	if [ ! -e "${BASE_CONFIG_FILE}" ]; then
		pwarning "$BASE_CONFIG_FILE could not be found! Using default config in the kernel repository as base config."
		make -C "${MODULE_WORK_DIR}/ksrc" defconfig
		[ -e "${MODULE_WORK_DIR}/ksrc/.config" ] || perror "Failed to create default kernel config."
		BASE_CONFIG_FILE="${MODULE_WORK_DIR}/ksrc/.config"
	fi
	
	# check for our wanted config parameter
	local OPENSLX_WANTED_CONFIG="${ROOT_DIR}/data/kernel.wanted.config"

	[ -e "${OPENSLX_WANTED_CONFIG}" ] || perror "$OPENSLX_WANTED_CONFIG does not exist! Please add a list of wanted kernel config parameters."

	# copy basic config file
	cp "$BASE_CONFIG_FILE" "$TARGET_CONFIG_FILE"

	for WANTED_CONFIG in $(cat $OPENSLX_WANTED_CONFIG|sort -u); do
		local CONFIG_PARAM_NAME="$(echo $WANTED_CONFIG | awk -F "=" '{print $1}')"
		local SEARCH_RESULT="$(grep -E "^\s*$(echo "$CONFIG_PARAM_NAME" | escape_search)=" "$BASE_CONFIG_FILE")"

		#echo "Process: $SEARCH_RESULT"
		# analyse results
		if [ "x$SEARCH_RESULT" == "x" ]; then
			# no match, add it
			sed -i -r "s/^\s*#.*\s$(echo "$CONFIG_PARAM_NAME" | escape_search)[^_A-Z0-9].*$//" "$TARGET_CONFIG_FILE"
			echo "$WANTED_CONFIG" >> "$TARGET_CONFIG_FILE"
		else
			# match, change to our setting if they differ
			if [ "x$SEARCH_RESULT" != "x$WANTED_CONFIG" ]; then
				sed -i "s/$(echo "$SEARCH_RESULT" | escape_search)/$(echo "$WANTED_CONFIG" | escape_replace)/" "$TARGET_CONFIG_FILE"
			fi
		fi
	done
}

# helper to patch aufs
patch_aufs() {
	local KERNEL_MAJOR=${REQUIRED_KERNEL%%.*}
	local AUFS="aufs${KERNEL_MAJOR}"
	pinfo "Cloning ${AUFS} standalone git"
	cd "${MODULE_WORK_DIR}"
	[ -d "${AUFS}-standalone/.git" ] && rm -rf "${AUFS}-standalone"		# if already there, kill it.
	# git: --depth 1 won't work here due to later "checkout origin/branch"
	if [ "$KERNEL_MAJOR" = "3" ]; then
		git clone "git://aufs.git.sourceforge.net/gitroot/aufs/${AUFS}-standalone.git" || perror "Cloning ${AUFS} failed."
	else
		git clone "git://github.com/sfjro/${AUFS}-standalone.git" || perror "Cloning ${AUFS} failed."
		#git clone "git://github.com/bnied/${AUFS}-standalone.git" || perror "Cloning ${AUFS} failed."
	fi
	# get the needed version
	cde "${MODULE_WORK_DIR}/${AUFS}-standalone"
	local branches=( $( git branch -r | grep -oE 'aufs[0-9\.\+]+$' ) )
	local major minor patch
	IFS=. read major minor patch _ <<<"$REQUIRED_KERNEL"
	if [ -z "$major" ] || [ -z "$minor" ]; then
		perror "REQUIRED_KERNEL not in properly set, this should not happen!"
	fi
	local testvar outer NEEDED_BRANCH
	while (( minor >= 0 )); do
		NEEDED_BRANCH="aufs${major}.${minor}"
		outer=false
		while (( patch > 0 )); do
			for testvar in "${branches[@]}"; do
				if [ "$testvar" = "${NEEDED_BRANCH}.${patch}" ] || [ "$testvar" = "${NEEDED_BRANCH}.${patch}+" ]; then
					NEEDED_BRANCH="$testvar"
					break 3
				elif [ "$testvar" = "${NEEDED_BRANCH}" ]; then
					outer=true
				fi
			done
			(( patch-- ))
		done
		$outer && break
		if (( patch == 0 )); then
			patch=500
			(( minor-- ))
		fi
	done
	pinfo "Getting branch origin/$NEEDED_BRANCH"
	git checkout "origin/$NEEDED_BRANCH" || git checkout "origin/${AUFS}.x-rcN" || perror "Could not checkout needed branch."
	pinfo "Starting to patch... $NEEDED_BRANCH"
	tarcopy "Documentation fs" "$MODULE_WORK_DIR/ksrc"

	# Quick-and-dirty aufs_type.h copying:
	[ -e "include/linux/aufs_type.h" ] && cp "include/linux/aufs_type.h" "$MODULE_WORK_DIR/ksrc/include/linux/"
	[ -e "include/uapi/linux/aufs_type.h" ] && cp "include/uapi/linux/aufs_type.h" "$MODULE_WORK_DIR/ksrc/include/uapi/linux/"

	cde "$MODULE_WORK_DIR/ksrc"

	local PATCH
	# Mandatory
	for PATCH in "${AUFS}-kbuild" "${AUFS}-base" "${AUFS}-mmap"; do
		patch -p1 < "$MODULE_WORK_DIR/${AUFS}-standalone/${PATCH}.patch" || perror "${PATCH}.patch failed!"
		pinfo "Applied '$MODULE_WORK_DIR/${AUFS}-standalone/${PATCH}.patch'"
	done
	# Optional - should we error too?
	for PATCH in "${AUFS}-loopback" "tmpfs-idr" "vfs-ino"; do
		[ -e "$MODULE_WORK_DIR/${AUFS}-standalone/${PATCH}.patch" ] || continue
		patch -p1 < "$MODULE_WORK_DIR/${AUFS}-standalone/${PATCH}.patch" || pwarning "${PATCH}.patch failed!"
		pinfo "Applied '$MODULE_WORK_DIR/${AUFS}-standalone/${PATCH}.patch'"
	done
	pinfo "Patched kernel source with ${NEEDED_BRANCH}"
	cde "$MODULE_WORK_DIR"
}