util/set_binary_flag_vpd

#!/bin/bash
#
# Copyright 2016 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.
#
# Helper script to update flag(s) (eg. block_devmode) in VPD which uses cached
# data from dump_vpd_log to avoid unnecessary vpd calls. This avoids both
# unnecessary reads and writes.
#
# The script works only with boolean data. This is done in order to be
# compatible with previous functionality of block_devmode flag and because for
# now we don't need other type of values.
#
# The script must not be run with untrusted input.
#
# Call with params
#   flag_name1 flag_value1 flag_name2 flag_value2...
#
# All the flag_values have to be either 1 or 0. Value of 0 is represented in the
# VPD by absence of the flag. The flag_names can contain only english
# alphanumeric characters and underscores.
#
# Example usage: set_binary_flag_vpd block_devmode 1 check_enrollment 0

set -e

arguments=()

for var in "$@"; do
  if [[ -z "${flag_name}" ]]; then
    if [[ -z "${var}" || "${var}" =~ [^a-zA-Z0-9_] ]]; then
      echo "Invalid param name: ${var}"
      exit 1
    fi
    flag_name="${var}"
  else
    current="$(dump_vpd_log --full --stdout | grep "^\"${flag_name}\"" || true)"
    if [[ "${var}" = 0 || "${var}" = 1 ]]; then
      expected="\"${flag_name}\"=\"${var}\""
      if [[ "${current}" != "${expected}" ]]; then
        arguments+=(-s)
        arguments+=("${flag_name}=${var}")
      fi
    else
      echo "Invalid param value: ${var}"
      exit 1
    fi
    flag_name=""
  fi
done

if [[ "${#arguments[@]}" != 0 ]]; then
  vpd -i RW_VPD "${arguments[@]}" || exit $?
  dump_vpd_log --force || exit $?
fi