Factored out the code to copy an image and modify it for test

mod_image_for_test.sh

 #!/bin/bash
 
 # Copyright (c) 2009 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 keyfob-based chromeos system image for testability.
 
 # --- BEGIN COMMON.SH BOILERPLATE ---
 # Load common CrOS utilities.  Inside the chroot this file is installed in
@@ skipping 33 matching lines @@
 DEFINE_string image "" "Location of the rootfs raw image file" i
 DEFINE_boolean installmask $FLAGS_TRUE \
     "Use INSTALL_MASK to shrink the resulting image." m
 DEFINE_integer jobs -1 \
     "How many packages to build in parallel at maximum." j
 DEFINE_string qualdb "" "Location of qualified component file" d
 DEFINE_boolean yes $FLAGS_FALSE "Answer yes to all prompts" y
 DEFINE_string build_root "/build" \
     "The root location for board sysroots."
 DEFINE_boolean fast ${DEFAULT_FAST} "Call many emerges in parallel"
+DEFINE_boolean inplace $FLAGS_TRUE \
+    "Modify/overwrite the image ${CHROMEOS_IMAGE_NAME} in place.  \
+Otherwise the image will be copied to ${CHROMEOS_TEST_IMAGE_NAME} \
+if needed, and  modified there"
+DEFINE_boolean force_copy ${FLAGS_FALSE} \
+    "Always rebuild test image if --noinplace"
 
 
 # Parse command line
 FLAGS "$@" || exit 1
 eval set -- "${FLAGS_ARGV}"
 
 EMERGE_CMD="emerge"
 EMERGE_BOARD_CMD="emerge-${FLAGS_board}"
 if [ "${FLAGS_fast}" -eq "${FLAGS_TRUE}" ]; then
   echo "Using alternate emerge"
   EMERGE_CMD="${SCRIPTS_DIR}/parallel_emerge"
   EMERGE_BOARD_CMD="${EMERGE_CMD} --board=${FLAGS_board}"
 fi
 
 # No board, no default and no image set then we can't find the image
 if [ -z $FLAGS_image ] && [ -z $FLAGS_board ] ; then
   setup_board_warning
   die "mod_image_for_test failed.  No board set and no image set"
 fi
 
 # We have a board name but no image set.  Use image at default location
 if [ -z $FLAGS_image ] ; then
   IMAGES_DIR="${DEFAULT_BUILD_ROOT}/images/${FLAGS_board}"
-  FILENAME="chromiumos_image.bin"
+  FILENAME="${CHROMEOS_IMAGE_NAME}"
   FLAGS_image="${IMAGES_DIR}/$(ls -t $IMAGES_DIR 2>&-| head -1)/${FILENAME}"
 fi
 
 # Turn path into an absolute path.
 FLAGS_image=`eval readlink -f ${FLAGS_image}`
 
 # Abort early if we can't find the image
 if [ ! -f $FLAGS_image ] ; then
   echo "No image found at $FLAGS_image"
   exit 1
@@ skipping 77 matching lines @@
       --exclude=site_tests/desktopui_UITest \
       --exclude=.svn \
       ${AUTOTEST_SRC}/client/* "${stateful_root}/${autotest_client}"
 
     sudo chmod 755 "${stateful_root}/${autotest_client}"
     sudo chown -R 1000:1000 "${stateful_root}/${autotest_client}"
 }
 
 # main process begins here.
 
+IMAGE_DIR="$(dirname "${FLAGS_image}")"
+
+# Copy the image to a test location if required
+if [ ${FLAGS_inplace} -eq ${FLAGS_FALSE} ]; then
+  TEST_PATHNAME="${IMAGE_DIR}/${CHROMEOS_TEST_IMAGE_NAME}"
+  if [ ! -f "${TEST_PATHNAME}" ] || \
+     [ ${FLAGS_force_copy} -eq ${FLAGS_TRUE} ] ; then
+    echo "Creating test image from original..."
+    ${COMMON_PV_CAT} "${FLAGS_image}" >"${TEST_PATHNAME}" \
+      || die "Cannot copy ${FLAGS_image} to test image"
+    FLAGS_image="${TEST_PATHNAME}"
+  else
+    echo "Using cached test image"
+    exit
+  fi
+
+  # No need to confirm now, since we are not overwriting the main image
+  FLAGS_yes="$FLAGS_TRUE"
+fi
+
 # Make sure this is really what the user wants, before nuking the device
 if [ $FLAGS_yes -ne $FLAGS_TRUE ]; then
   read -p "Modifying image ${FLAGS_image} for test; are you sure (y/N)? " SURE
   SURE="${SURE:0:1}" # Get just the first character
   if [ "$SURE" != "y" ]; then
     echo "Ok, better safe than sorry."
     exit 1
   fi
 else
   echo "Modifying image ${FLAGS_image} for test..."
@@ skipping 63 matching lines @@
 cleanup
 
 # Now make it bootable with the flags from build_image
 "${SCRIPTS_DIR}/bin/cros_make_image_bootable" "$(dirname "${FLAGS_image}")" \
                                             $(basename "${FLAGS_image}")
 
 print_time_elapsed
 
 trap - EXIT