crypto.py 文件源码

def writeKeyToFile(key, filename):
    """Write **key** to **filename**, with ``0400`` permissions.

    If **filename** doesn't exist, it will be created. If it does exist
    already, and is writable by the owner of the current process, then it will
    be truncated to zero-length and overwritten.

    :param bytes key: A key (or some other private data) to write to
        **filename**.
    :param str filename: The path of the file to write to.
    :raises: Any exceptions which may occur.
    """
    logging.info("Writing key to file: %r", filename)
    flags = os.O_WRONLY | os.O_TRUNC | os.O_CREAT | getattr(os, "O_BIN", 0)
    fd = os.open(filename, flags, 0400)
    os.write(fd, key)
    os.fsync(fd)
    os.close(fd)