Check Access Permissions (continued.)

  /* all directories in the path exist and are executable.   */
  /* now check existance and read access to the file itself. */
  if (access(file_path, F_OK) == -1) {
    sprintf(err_msg, "File does not exist.");
    return 0;
  }
  if (access(file_path, R_OK) == -1) {
    sprintf(err_msg, "no read access to file.");
    return 0;
  }

  /* all tests passed. */
  return 1;
}