def _RunOsLoginControl(self, params):
    """Run the OS Login control script.

    Args:
      params: list, the params to pass to the script

    Returns:
      int, the return code from the call, or None if the script is not found.
    """
    try:
      return subprocess.call([constants.OSLOGIN_CONTROL_SCRIPT] + params)
    except OSError as e:
      if e.errno == errno.ENOENT:
        return None
      else:
        raise
Run the OS Login control script.

    Args:
      params: list, the params to pass to the script

    Returns:
      int, the return code from the call, or None if the script is not found.