testing/libfuzzer/gen_fuzzer_config.py

#!/usr/bin/python2
#
# Copyright (c) 2015 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Generate or update an existing config (.options file) for libfuzzer test.

Invoked by GN from fuzzer_test.gni.
"""

import ConfigParser
import argparse
import os
import sys

def AddSectionOptions(config, section_name, options):
  """Add |options| to the |section_name| section of |config|. Throws an
  assertion error if any option in |options| does not have exactly two
  elements."""
  if not options:
    return

  config.add_section(section_name)
  for option_and_value in options:
    assert len(option_and_value) == 2, (
        '%s is not an option, value pair' % option_and_value)

    config.set(section_name, *option_and_value)


def main():
  parser = argparse.ArgumentParser(description="Generate fuzzer config.")
  parser.add_argument('--config', required=True)
  parser.add_argument('--dict')
  parser.add_argument('--libfuzzer_options', nargs='+', default=[])
  parser.add_argument('--environment_variables', nargs='+', default=[],
                      choices=['AFL_DRIVER_DONT_DEFER=1'])
  args = parser.parse_args()

  # Script shouldn't be invoked without any arguments, but just in case.
  if not (args.dict or args.libfuzzer_options or args.environment_variables):
    return

  config = ConfigParser.ConfigParser()
  libfuzzer_options = []
  if args.dict:
      libfuzzer_options.append(('dict', os.path.basename(args.dict)))
  libfuzzer_options.extend(option.split('=')
                           for option in args.libfuzzer_options)

  AddSectionOptions(config, 'libfuzzer', libfuzzer_options)
  AddSectionOptions(config, 'env',
                    [option.split('=') for option in args.environment_variables]
  )

  # Generate .options file.
  config_path = args.config
  with open(config_path, 'w') as options_file:
    options_file.write(
        '# This is an automatically generated config for ClusterFuzz.\n')
    config.write(options_file)

if __name__ == '__main__':
  main()