New helper script to mount (and umount) gpt image into image_dir/rootfs and mount /var, /usr/local

src/scripts/prep_usb.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.
-
-# 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_boolean "unmount" $FLAGS_FALSE "unmount USB partitions" "u"
-DEFINE_string "device" "/dev/sdc" \
-    "The device on which the mountable partitions live." "d"
-DEFINE_string "rootfs_mountpt" "/tmp/m" "Mount point for rootfs" "r"
-DEFINE_string "stateful_mountpt" "/tmp/s" \
-    "Mount point for stateful partition" "s"
-
-# Parse command line.
-FLAGS "$@" || exit 1
-eval set -- "${FLAGS_ARGV}"
-
-mkdir -p "${FLAGS_rootfs_mountpt}"
-mkdir -p "${FLAGS_stateful_mountpt}"
-
-if [[ $FLAGS_unmount -eq $FLAGS_FALSE ]]; then
-  sudo mount "${FLAGS_device}3" "${FLAGS_rootfs_mountpt}"
-  sudo mount "${FLAGS_device}1" "${FLAGS_stateful_mountpt}"
-  sudo mount --bind "${FLAGS_stateful_mountpt}/var" \
-      "${FLAGS_rootfs_mountpt}/var"
-  echo "RootFS of bootable medium mounted at ${FLAGS_rootfs_mountpt}."
-else
-  echo "Attempting to unmount ${FLAGS_stateful_mountpt} " \
-      "and ${FLAGS_rootfs_mountpt}"
-  sudo umount "${FLAGS_rootfs_mountpt}/var"
-  sudo umount "${FLAGS_stateful_mountpt}"
-  sudo umount "${FLAGS_rootfs_mountpt}"
-fi