Add a utility to tag/stamp image

There are several procedures in Chrome OS post-processing before being released:
stamping, tagging, mod image for URLs, ... and signing.
We need an integrated script to handle all the stamping / tagging.

This CL can handle empty tag files like /root/.force_update_firmware
or /root/.dev_mode.

This CL deprecates http://codereview.chromium.org/3421040 and moved script
from crosutils to vboot_reference. In the future we may isolate the non-signing
post-processing scripts (set_lsb, tag_image, remove_label, ...) into crosutils.

BUG=none
TEST=manually:
(1) Build a general dev image without firmware updates (default behavior of build_image for x86-generic ToT)
(2) Enter chroot and then execute:
    cd ~/trunk/src/platform/vboot_reference/scripts;
    ./tag_image.sh \
      --from ~/trunk/src/build/images/x86-generic/latest/chromiumos_image.bin
    Expected: output message:
      Update Firmware: disabled
      Developer Mode: Enabled
(3) ./tag_image.sh --update_firmware=1 --dev_mode=0 \
      --from ~/trunk/src//build/images/x86-generic/latest/chromiumos_image.bin
    Expected: output message:
      Update Firmware: disabled => Enabled
      Developer Mode: Enabled => disabled

    Manually verify:
      pushd ../../build/images/x86-generic/latest
      unpack_partitions.sh chromiumos_image.bin
      sudo mount -o loop,ro part_3 rootfs
      ls -l rootfs/root/.force_update_firmware # this file should exist
      ls -l rootfs/root/.dev_mode # this file should NOT exist (i.e., error)
      sudo umount rootfs

(4) ./tag_image.sh --update_firmware=0 --dev_mod=1 \
      --from ~/trunk/src/build/images/x86-generic/latest/chromiumos_image.bin
    Expected: output message:
      Update Firmware: Enabled => disabled
      Developer Mode: disabled => Enabled

    Manually verify:
      pushd ../../build/images/x86-generic/latest
      unpack_partitions.sh chromiumos_image.bin
      sudo mount -o loop,ro part_3 rootfs
      ls -l rootfs/root/.force_update_firmware # this file should NOT exist (i.e., error)
      ls -l rootfs/root/.dev_mode # this file should exist
      sudo umount rootfs

Change-Id: I96af3c7201372bb904426d10cff142467a1fa2e7

Review URL: http://codereview.chromium.org/3604001

scripts/image_signing/common.sh

@@ -9,6 +9,16 @@ SCRIPT_DIR=$(dirname $0)
 PROG=$(basename $0)
 GPT=cgpt
 
+# The tag when the rootfs is changed.
+TAG_NEEDS_TO_BE_SIGNED="/root/.need_to_be_signed"
+
+# Load shflags
+if [[ -f /usr/lib/shflags ]]; then
+  . /usr/lib/shflags
+else
+  . "${SCRIPT_DIR}/lib/shflags/shflags"
+fi
+
 # List of Temporary files and mount points.
 TEMP_FILE_LIST=$(mktemp)
 TEMP_DIR_LIST=$(mktemp)
@@ -27,6 +37,38 @@ partsize() {
   sudo $GPT show -s -i $2 $1
 }
 
+# Tags a file system as "needs to be resigned".
+# Args: MOUNTDIRECTORY
+tag_as_needs_to_be_resigned() {
+  local mount_dir="$1"
+  sudo touch "$mount_dir/$TAG_NEEDS_TO_BE_SIGNED"
+}
+
+# Determines if the target file system has the tag for resign
+# Args: MOUNTDIRECTORY
+# Returns: $FLAGS_TRUE if the tag is there, otherwise $FLAGS_FALSE
+has_needs_to_be_resigned_tag() {
+  local mount_dir="$1"
+  if [ -f "$mount_dir/$TAG_NEEDS_TO_BE_SIGNED" ]; then
+    return ${FLAGS_TRUE}
+  else
+    return ${FLAGS_FALSE}
+  fi
+}
+
+# Determines if the target file system is a Chrome OS root fs
+# Args: MOUNTDIRECTORY
+# Returns: $FLAGS_TRUE if MOUNTDIRECTORY looks like root fs,
+#          otherwise $FLAGS_FALSE
+is_rootfs_partition() {
+  local mount_dir="$1"
+  if [ -f "$mount_dir/$(dirname "$TAG_NEEDS_TO_BE_SIGNED")" ]; then
+    return ${FLAGS_TRUE}
+  else
+    return ${FLAGS_FALSE}
+  fi
+}
+
 # Mount a partition read-only from an image into a local directory
 # Args: IMAGE PARTNUM MOUNTDIRECTORY
 mount_image_partition_ro() {
@@ -45,6 +87,9 @@ mount_image_partition() {
   local mount_dir=$3
   local offset=$(partoffset "$image" "$partnum")
   sudo mount -o loop,offset=$((offset * 512)) "$image" "$mount_dir"
+  if is_rootfs_partition "$mount_dir"; then
+    tag_as_needs_to_be_resigned "$mount_dir"
+  fi
 }
 
 # Extract a partition to a file
@@ -93,6 +138,9 @@ cleanup_temps_and_mounts() {
   set +e  # umount may fail for unmounted directories
   for i in "$(cat $TEMP_DIR_LIST)"; do
     if [ -n "$i" ]; then
+      if has_needs_to_be_resigned_tag "$i"; then
+        echo "Warning: image may be modified. Please resign image."
+      fi
       sudo umount -d $i 2>/dev/null
       rm -rf $i
     fi

scripts/image_signing/lib/shflags/README.chromium

@@ -0,0 +1 @@
+This is r137 of shflags

scripts/image_signing/sign_official_build.sh

@@ -122,6 +122,17 @@ update_rootfs_hash() {
   local keyblock=$2  # Keyblock for re-generating signed kernel partition
   local signprivate=$3  # Private key to use for signing.
 
+  # check and clear need_to_resign tag
+  local rootfs_dir=$(make_temp_dir)
+  mount_image_partition_ro "${image}" 3 "${rootfs_dir}"
+  if has_needs_to_be_resigned_tag "${rootfs_dir}"; then
+    # remount as RW
+    sudo umount -d "${rootfs_dir}"
+    mount_image_partition "${image}" 3 "${rootfs_dir}"
+    sudo rm -f "${rootfs_dir}/${TAG_NEEDS_TO_BE_SIGNED}"
+  fi
+  sudo umount -d "${rootfs_dir}"
+
   local rootfs_image=$(make_temp_file)
   extract_image_partition ${image} 3 ${rootfs_image}
   local kernel_config=$(grab_kernel_config "${image}")
@@ -180,7 +191,7 @@ resign_firmware_payload() {
   mount_image_partition ${image} 3 ${rootfs_dir}
   # Force unmount of the rootfs on function exit as it is needed later.
   trap "sudo umount -d ${rootfs_dir}" RETURN
-  
+
   local shellball_dir=$(make_temp_dir)
   # get_firmwarebin_from_shellball can fail if the image has no 
   # firmware update.

scripts/image_signing/tag_image.sh

@@ -0,0 +1,158 @@
+#!/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 manipulate the tag files in the output of build_image
+
+# Load common constants.  This should be the first executable line.
+# The path to common.sh should be relative to your script's location.
+. "$(dirname "$0")/common.sh"
+
+DEFINE_string from "chromiumos_image.bin" \
+  "Input file name of Chrome OS image to tag/stamp."
+DEFINE_string update_firmware "" \
+  "Tag to force updating firmware (1 to enable, 0 to disable)"
+DEFINE_string dev_mode "" \
+  "Tag for developer mode (1 to enable, 0 to disable)"
+
+# Parse command line
+FLAGS "$@" || exit 1
+eval set -- "${FLAGS_ARGV}"
+
+# Abort on error
+set -e
+
+if [ -z ${FLAGS_from} ] || [ ! -f ${FLAGS_from} ] ; then
+  echo "Error: invalid flag --from"
+  exit 1
+fi
+
+# Global variable to track if image is modified.
+g_modified=${FLAGS_FALSE}
+
+# Processes (enable, disable, or simply report) a tag file.
+# Args: DO_MODIFICATION NAME ROOT TAG_FILE ACTION
+#
+# When DO_MODIFICATION=${FLAGS_TRUE},
+#  Creates (ACTION=1) the TAG_FILE in ROOT, or
+#  removes (ACTION=0) the TAG_FILE in ROOT, then
+#  reports the status (and change) to the tag file.
+# When DO_MODIFICATION=${FLAGS_FALSE},
+#  make a dry-run and only change ${g_modified}
+function process_tag() {
+  local tag_status_text=""
+  local do_modification="$1"
+  local name="$2"
+  local root="$3"
+  local tag_file_path="$3/$4"
+  local action="$5"
+  local do_enable=${FLAGS_FALSE}
+  local do_disable=${FLAGS_FALSE}
+
+  # only 1, 0, and "" are valid params to action.
+  case "${action}" in
+    "1" )
+      do_enable=${FLAGS_TRUE}
+      ;;
+    "0" )
+      do_disable=${FLAGS_TRUE}
+      ;;
+    "" )
+      ;;
+    * )
+      echo "Error: invalid param to ${name}: ${action} (must be 1 or 0)."
+      exit 1
+      ;;
+  esac
+
+  if [ -f "${tag_file_path}" ]; then
+    tag_status_text="ENABLED"
+    if [ "${do_disable}" = ${FLAGS_TRUE} ]; then
+      # disable the tag
+      if [ "${do_modification}" = ${FLAGS_TRUE} ]; then
+        sudo rm "${tag_file_path}"
+      fi
+      g_modified=${FLAGS_TRUE}
+      tag_status_text="${tag_status_text} => disabled"
+    elif [ "${do_disable}" != ${FLAGS_FALSE} ]; then
+      # internal error
+      echo "Internal error for tag ${name}: need disable param." 1>&2
+      exit 1
+    fi
+  else
+    tag_status_text="disabled"
+    if [ "${do_enable}" = ${FLAGS_TRUE} ]; then
+      # enable the tag
+      if [ "${do_modification}" = ${FLAGS_TRUE} ]; then
+        sudo touch "${tag_file_path}"
+      fi
+      g_modified=${FLAGS_TRUE}
+      tag_status_text="${tag_status_text} => ENABLED"
+    elif [ "${do_enable}" != ${FLAGS_FALSE} ]; then
+      # internal error
+      echo "Internal error for tag ${name}: need enable param." 1>&2
+      exit 1
+    fi
+  fi
+
+  # report tag status
+  if [ "${do_modification}" != ${FLAGS_TRUE} ]; then
+    echo "${name}: ${tag_status_text}"
+  fi
+}
+
+# Iterates all tags to a given partition root.
+# Args: ROOTFS DO_MODIFICATION
+#
+# Check process_tag for the meaning of parameters.
+process_all_tags() {
+  local rootfs="$1"
+  local do_modification="$2"
+
+  process_tag "${do_modification}" \
+    "Update Firmware" \
+    "${rootfs}" \
+    /root/.force_update_firmware \
+    "${FLAGS_update_firmware}"
+
+  process_tag "${do_modification}" \
+    "Developer Mode" \
+    "${rootfs}" \
+    /root/.dev_mode \
+    "${FLAGS_dev_mode}"
+}
+
+IMAGE=$(readlink -f "${FLAGS_from}")
+if [[ -z "${IMAGE}" || ! -f "${IMAGE}" ]]; then
+  echo "Missing required argument: --from (image to update)"
+  usage
+  exit 1
+fi
+
+# First round, mount as read-only and check if we read any modification.
+rootfs=$(make_temp_dir)
+mount_image_partition_ro "${IMAGE}" 3 "${rootfs}"
+
+# we don't have tags in stateful partition yet...
+# stateful_dir=$(make_temp_dir)
+# mount_image_partition ${IMAGE} 1 ${stateful_dir}
+
+process_all_tags "${rootfs}" ${FLAGS_FALSE}
+
+if [ ${g_modified} = ${FLAGS_TRUE} ]; then
+  # remount as RW (we can't use mount -o rw,remount because of loop device)
+  sudo umount -d "${rootfs}"
+  mount_image_partition "${IMAGE}" 3 "${rootfs}"
+
+  # Second round, apply the modification to image.
+  process_all_tags "${rootfs}" ${FLAGS_TRUE}
+
+  # this is supposed to be automatically done in mount_image_partition,
+  # but it's no harm to explicitly make it again here.
+  tag_as_needs_to_be_resigned "${rootfs}"
+  echo "IMAGE IS MODIFIED. PLEASE REMEMBER TO RESIGN YOUR IMAGE."
+else
+  echo "Image is not modified."
+fi