def client_thread(conn, addr, data_directory, sm4_key):

    # 验证用户名和密码

    username = conn.recv(1024).decode()

    password = conn.recv(1024).decode()

    if users.get(username) == password:

        conn.send(b'Authentication successful')

       

        # 接收文件名并发送文件

        filename = conn.recv(1024).decode()

        # 请求的文件已加密

        if filename + ".encrypted" in os.listdir(data_directory):

            # 解密文件

            decrypt_one_file(filename, data_directory, sm4_key)

            complete_filename = os.path.join(data_directory, filename)

            send_encrypted_file(conn, complete_filename, password)

            # 加密文件

            encrypt_one_file(filename, data_directory, sm4_key)

        # 请求的文件未加密

        elif filename in os.listdir(data_directory):

            send_encrypted_file(conn, filename, password)

        else:

            conn.send(b'no such file')

    else:

        conn.send(b'Authentication failed')

    conn.close()

def waiting_for_client(data_directory, sm4_key):

    global stop_thread

    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    server.bind(('localhost', 54321))

    server.listen(5)

    server.settimeout(3.0)  # 设置超时时间

    while not stop_thread.is_set():

        try:

            conn, addr = server.accept()

            # 处理连接

            threading.Thread(target=client_thread, args=(conn, addr, data_directory, sm4_key)).start()

        except socket.timeout:

            continue  # 超时，回到循环的开始处检查条件

        except Exception as e:

            break  # 其他异常，退出循环