1 files changed, 82 insertions, 0 deletions
diff --git a/include/mrc.sh b/include/mrc.sh
new file mode 100755
index 00000000..b9345b92
--- /dev/null
+++ b/include/mrc.sh
@@ -0,0 +1,82 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+# Logic based on util/chromeos/crosfirmware.sh in coreboot cfc26ce278.
+# Modifications in this version are Copyright 2021 and 2023 Leah Rowe.
+# Original copyright detailed in repo: https://review.coreboot.org/coreboot/
+
+extract_mrc()
+{
+	[ -z "${MRC_board}" ] && err "extract_mrc $MRC_hash: MRC_board not set"
+	[ -z "${CONFIG_MRC_FILE}" ] && \
+		err "extract_mrc $MRC_hash: CONFIG_MRC_FILE not set"
+
+	_file="${MRC_url##*/}"
+	_file="${_file%.zip}"
+	_mrc_destination="${CONFIG_MRC_FILE#../../}"
+	mkdirs "${_mrc_destination}" "extract_mrc" || return 0
+
+	(
+	cd "${appdir}" || err "extract_mrc: !cd ${appdir}"
+	extract_partition ROOT-A "${_file}" root-a.ext2
+	extract_shellball root-a.ext2 chromeos-firmwareupdate-${MRC_board}
+	extract_coreboot chromeos-firmwareupdate-${MRC_board}
+	)
+
+	"${cbfstool}" "${appdir}/"coreboot-*.bin extract -n mrc.bin \
+	    -f "${_mrc_destination}" -r RO_SECTION || \
+	    err "extract_mrc: could not fetch mrc.bin"
+}
+
+extract_partition()
+{
+	NAME=${1}
+	FILE=${2}
+	ROOTFS=${3}
+	_bs=1024
+
+	printf "Extracting ROOT-A partition\n"
+	ROOTP=$( printf "unit\nB\nprint\nquit\n" | \
+	    parted "${FILE}" 2>/dev/null | grep "${NAME}" )
+
+	START=$(( $( echo ${ROOTP} | cut -f2 -d\ | tr -d "B" ) ))
+	SIZE=$(( $( echo ${ROOTP} | cut -f4 -d\ | tr -d "B" ) ))
+
+	dd if="${FILE}" of="${ROOTFS}" bs=${_bs} skip=$(( ${START} / ${_bs} )) \
+	    count=$(( ${SIZE} / ${_bs} )) || \
+	    err "extract_partition: can't extract root file system"
+}
+
+extract_shellball()
+{
+	ROOTFS=${1}
+	SHELLBALL=${2}
+
+	printf "Extracting chromeos-firmwareupdate\n"
+	printf "cd /usr/sbin\ndump chromeos-firmwareupdate ${SHELLBALL}\nquit" \
+	    | debugfs "${ROOTFS}" || err "extract_shellball: debugfs"
+}
+
+extract_coreboot()
+{
+	_shellball=${1}
+	_unpacked=$( mktemp -d )
+
+	printf "Extracting coreboot image\n"
+	[ -f "${_shellball}" ] || \
+	    err "extract_coreboot: shellball missing in google cros image"
+	sh "${_shellball}" --unpack "${_unpacked}" || \
+	    err "extract_coreboot: shellball exits with non-zero status"
+
+	# TODO: audit the f* out of that shellball, for each mrc version.
+	# it has to be updated for each mrc update. we should ideally
+	# implement the functionality ourselves.
+
+	[ -f "${_unpacked}/VERSION" ] || \
+	    err "extract_coreboot: VERSION file missing on google coreboot rom"
+
+	_version=$( cat "${_unpacked}/VERSION" | grep BIOS\ version: | \
+	    cut -f2 -d: | tr -d \  )
+
+	cp "${_unpacked}/bios.bin" "coreboot-${_version}.bin" || \
+	    err "extract_coreboot: cannot copy google cros rom"
+}