build_library/cgpt_shell.sh

#!/bin/sh
# Copyright (c) 2012 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.

# This script is automatically generated by @SCRIPT_GENERATOR@.
# Do not edit!

if ! type numsectors >/dev/null 2>&1; then
  . "/usr/share/misc/chromeos-common.sh" || exit 1
fi
locate_gpt

# Usage: create_image <device> <min_disk_size>
# If <device> is a block device, wipes out the GPT
# If it's not, it creates a new file of the requested size
create_image() {
  local dev="$1"
  local min_disk_size="$2"

  if [ -b "${dev}" ]; then
    # Make sure block size is not greater than 8K. Otherwise the partition
    # start calculation won't fit.
    block_size=$(blocksize "${dev}")
    if [ "${block_size}" -gt 8192 ]; then
      echo "Destination blocksize too large. Only blocksizes of 8192 bytes and \
        smaller are supported." >&2
      exit 1
    fi

    # Zap any old partitions (otherwise gpt complains).
    dd if=/dev/zero of="${dev}" conv=notrunc bs=512 count=64
    dd if=/dev/zero of="${dev}" conv=notrunc bs=512 count=64 \
      seek=$(( min_disk_size / 512 - 64 ))
  else
    if [ ! -e "${dev}" ]; then
      # Align to 512 bytes
      min_disk_size=$(( (min_disk_size + 511) & ~511 ))
      truncate -s "${min_disk_size}" "${dev}"
    fi
  fi
}