Add 'boot_signature_info' utility am: 41681b2656 am: 94173bdd71
Original change: https://android-review.googlesource.com/c/platform/system/tools/mkbootimg/+/1960407
Change-Id: I5ac061fadd8a32a44eba7606cd13ee44ff3b3c3f
diff --git a/gki/boot_signature_info.sh b/gki/boot_signature_info.sh
new file mode 100755
index 0000000..67ea0c9
--- /dev/null
+++ b/gki/boot_signature_info.sh
@@ -0,0 +1,97 @@
+#!/bin/bash
+#
+# Copyright (C) 2022 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+#
+# Dump boot signature info of a GKI boot image.
+#
+
+set -eo errtrace
+
+die() {
+ echo >&2 "ERROR:" "${@}"
+ exit 1
+}
+
+TEMP_DIR="$(mktemp -d)"
+readonly TEMP_DIR
+
+exit_handler() {
+ readonly EXIT_CODE="$?"
+ rm -rf "${TEMP_DIR}" ||:
+ exit "${EXIT_CODE}"
+}
+
+trap exit_handler EXIT
+trap 'die "line ${LINENO}, ${FUNCNAME:-<main>}(): \"${BASH_COMMAND}\" returned \"$?\"" ' ERR
+
+get_arg() {
+ local arg="$1"
+ shift
+ while [[ "$#" -gt 0 ]]; do
+ if [[ "$1" == "${arg}" ]]; then
+ shift
+ echo "$1"
+ return
+ fi
+ shift
+ done
+}
+
+readonly VBMETA_IMAGE="${TEMP_DIR}/boot.boot_signature"
+readonly VBMETA_IMAGE_TEMP="${VBMETA_IMAGE}.temp"
+readonly VBMETA_INFO="${VBMETA_IMAGE}.info"
+readonly BOOT_IMAGE="${TEMP_DIR}/boot.img"
+readonly BOOT_IMAGE_DIR="${TEMP_DIR}/boot.unpack_dir"
+readonly BOOT_IMAGE_ARGS="${TEMP_DIR}/boot.mkbootimg_args"
+
+[[ -f "$1" ]] ||
+ die "expected one input image"
+cp "$1" "${BOOT_IMAGE}"
+
+# This could fail if there already is no AVB footer.
+avbtool erase_footer --image "${BOOT_IMAGE}" 2>/dev/null ||:
+
+unpack_bootimg --boot_img "${BOOT_IMAGE}" --out "${BOOT_IMAGE_DIR}" \
+ --format=mkbootimg -0 > "${BOOT_IMAGE_ARGS}"
+
+declare -a boot_args=()
+while IFS= read -r -d '' ARG; do
+ boot_args+=("${ARG}")
+done < "${BOOT_IMAGE_ARGS}"
+
+BOOT_IMAGE_VERSION="$(get_arg --header_version "${boot_args[@]}")"
+if [[ "${BOOT_IMAGE_VERSION}" -ge 4 ]]; then
+ cp "${BOOT_IMAGE_DIR}/boot_signature" "${VBMETA_IMAGE}"
+else
+ tail -c "$(( 16 << 10 ))" "${BOOT_IMAGE}" > "${VBMETA_IMAGE}"
+fi
+
+# Keep carving out vbmeta image from the boot signature until we fail or EOF.
+# Failing is fine because there could be padding trailing the boot signature.
+while avbtool info_image --image "${VBMETA_IMAGE}" --output "${VBMETA_INFO}" 2>/dev/null; do
+ cat "${VBMETA_INFO}"
+ echo
+
+ declare -i H A X
+ H="$(cat "${VBMETA_INFO}" | grep 'Header Block:' | awk '{print $3}')"
+ A="$(cat "${VBMETA_INFO}" | grep 'Authentication Block:' | awk '{print $3}')"
+ X="$(cat "${VBMETA_INFO}" | grep 'Auxiliary Block:' | awk '{print $3}')"
+ vbmeta_size="$(( ${H} + ${A} + ${X} ))"
+
+ tail -c "+$(( ${vbmeta_size} + 1 ))" "${VBMETA_IMAGE}" > "${VBMETA_IMAGE_TEMP}"
+ cp "${VBMETA_IMAGE_TEMP}" "${VBMETA_IMAGE}"
+done
