recovery installer: fix build_gpt and build_image

mod_image_for_recovery.sh

+#!/bin/bash
+
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Script to modify a pristine/dev Chrome OS image to be used for recovery
+
+. "$(dirname "$0")/common.sh"
+
+# Script must be run inside the chroot.
+restart_in_chroot_if_needed $*
+
+DEFINE_string image_dir "" \
+  "Directory to pristine/base image."
+DEFINE_string image_name "chromiumos_image.bin" \
+  "Name of Chrome OS image to modify."
+
+# Parse command line
+FLAGS "$@" || exit 1
+eval set -- "${FLAGS_ARGV}"
+
+set -e
+
+if [ -z $FLAGS_image_dir ] || [ ! -d $FLAGS_image_dir ]; then
+  echo "Error: invalid flag --image_dir"
+  exit 1
+fi
+
+SRC_PATH="${FLAGS_image_dir}/${FLAGS_image_name}"
+if [ -z $FLAGS_image_name ] || [ ! -f $SRC_PATH ]; then
+  echo "Error: invalid flag --image_name"
+  exit 1
+fi
+
+# Constants
+OUTPUT_DIR=$FLAGS_image_dir
+ROOT_FS_DIR="${OUTPUT_DIR}/rootfs"
+STATEFUL_FS_DIR="${OUTPUT_DIR}/stateful_partition"
+RECOVERY_IMAGE="recovery_image.bin"
+
+mount_gpt_cleanup() {
+  "${SCRIPTS_DIR}/mount_gpt_image.sh" -u -r "$1" -s "$2"
+}
+
+# Modifies an existing image for recovery use
+update_recovery_packages() {
+  local image_name=$1
+  local sector_size=512  # sector size in bytes
+  local num_sectors_vb=128  # number of sectors in kernel verification blob
+  # Start offset of kernel A (aligned to 4096-sector boundary)
+  local start_kern_a=4096
+  local vb_file="${STATEFUL_FS_DIR}/verification_blob.kernel"
+
+  echo "Modifying image ${image_name} for recovery use"
+
+  trap "mount_gpt_cleanup \"${ROOT_FS_DIR}\" \"${STATEFUL_FS_DIR}\"" EXIT
+
+  ${SCRIPTS_DIR}/mount_gpt_image.sh --from "${OUTPUT_DIR}" \
+    --image "$( basename ${image_name} )" -r "${ROOT_FS_DIR}" \
+    -s "${STATEFUL_FS_DIR}"
+
+  # Mark the image as a recovery image (needed for recovery boot)
+  sudo touch "${STATEFUL_FS_DIR}/.recovery"
+
+  # Copy verification blob out of kernel A into stateful partition
+  # so that we can restore it during recovery
+  sudo touch $vb_file
+  echo "Backing up kernel verification blob onto stateful partition ..."
+  sudo dd if="$image_name" of="$vb_file" skip=$start_kern_a bs=$sector_size \
+      count=$num_sectors_vb conv=notrunc
+
+  # Overwrite verification blob with recovery image verification blob
+  # TODO(tgao): resign kernel for recovery image
+  echo "Overwrite kernel verification blob with resigned blob for recovery..."
+  sudo dd if=/dev/zero of="$image_name" seek=$start_kern_a bs=$sector_size \
+      count=$num_sectors_vb conv=notrunc
+
+  trap - EXIT
+  ${SCRIPTS_DIR}/mount_gpt_image.sh -u -r "${ROOT_FS_DIR}" \
+      -s "${STATEFUL_FS_DIR}"
+}
+
+# Main
+
+DST_PATH="${OUTPUT_DIR}/${RECOVERY_IMAGE}"
+echo "Making a copy of original image ${SRC_PATH}"
+cp $SRC_PATH $DST_PATH
+update_recovery_packages $DST_PATH
+echo "Recovery image created at ${DST_PATH}"