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Newbyte
Asked: 2024-07-23 21:55:44 +0800 CST

尝试通过 dbus-fast 调用 org.freedesktop.login1.Manager 上的 Inhibit 方法时出现 EOFError

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我正在开发一个 Python 应用程序，它将以各种形式（Flatpak、PyInstaller 可执行文件，也许还有其他）分发给 Linux 上的用户。在这个应用程序中，我想调用dbus 接口Inhibit上的方法org.freedesktop.login1.Manager。由于相对复杂/多样化的分发要求，我选择了 dbus-fast，它是 dbus 的纯 Python 实现。此外，dbus-python 的作者在库文档的开头就给出了各种警告，这是 dbus-fast 的另一个优点。

无论如何，dbus-fast 似乎总体上运行良好，并且我能够ListUsers毫无问题地调用该方法，如下所示：

import asyncio
from dbus_fast import BusType
from dbus_fast.aio import MessageBus

async def list_users() -> None:
    system_bus = await MessageBus(bus_type=BusType.SYSTEM).connect()
    introspection = await system_bus.introspect(
        "org.freedesktop.login1",
        "/org/freedesktop/login1",
    )
    login_object = system_bus.get_proxy_object(
        "org.freedesktop.login1",
        "/org/freedesktop/login1",
        introspection,
    )
    login_manager_interface = login_object.get_interface(
        "org.freedesktop.login1.Manager",
    )

    user_list = await login_manager_interface.call_list_users()
    print(user_list)

asyncio.run(list_users())

然后我可以运行并获取如下列表：

$ python -m dbus_list_users
[[1000, 'newbyte', '/org/freedesktop/login1/user/_1000']]

但是，如果我尝试调用该Inhibit方法，则会得到EOFError，我不明白在这种情况下它的含义。以下是代码：

import asyncio
from dbus_fast import BusType
from dbus_fast.aio import MessageBus

async def do_inhibit() -> None:
    system_bus = await MessageBus(bus_type=BusType.SYSTEM).connect()
    introspection = await system_bus.introspect(
        "org.freedesktop.login1",
        "/org/freedesktop/login1",
    )
    login_object = system_bus.get_proxy_object(
        "org.freedesktop.login1",
        "/org/freedesktop/login1",
        introspection,
    )
    login_manager_interface = login_object.get_interface(
        "org.freedesktop.login1.Manager",
    )

    inhibit_fd = await login_manager_interface.call_inhibit(
        "sleep",
        "Stack Overflow example man",
        "To demonstrate that it does not work",
        "delay",
    )
    print(inhibit_fd)

asyncio.run(do_inhibit())

运行它给了我这个很长的回溯：

$ python -m dbus_inhibit
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/mnt/storage/Programming/sparvio_toolbox/dbus_inhibit.py", line 28, in <module>
    asyncio.run(do_inhibit())
  File "/usr/lib64/python3.12/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.12/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.12/asyncio/base_events.py", line 687, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "/mnt/storage/Programming/sparvio_toolbox/dbus_inhibit.py", line 20, in do_inhibit
    inhibit_fd = await login_manager_interface.call_inhibit(
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/mnt/storage/Programming/sparvio_toolbox/_host-env/lib64/python3.12/site-packages/dbus_fast/aio/proxy_object.py", line 92, in method_fn
    msg = await self.bus.call(
          ^^^^^^^^^^^^^^^^^^^^
  File "/mnt/storage/Programming/sparvio_toolbox/_host-env/lib64/python3.12/site-packages/dbus_fast/aio/message_bus.py", line 385, in call
    await future
  File "src/dbus_fast/aio/message_reader.py", line 19, in dbus_fast.aio.message_reader._message_reader
  File "src/dbus_fast/_private/unmarshaller.py", line 775, in dbus_fast._private.unmarshaller.Unmarshaller._unmarshall
  File "src/dbus_fast/_private/unmarshaller.py", line 636, in dbus_fast._private.unmarshaller.Unmarshaller._read_header
  File "src/dbus_fast/_private/unmarshaller.py", line 376, in dbus_fast._private.unmarshaller.Unmarshaller._read_to_pos
  File "src/dbus_fast/_private/unmarshaller.py", line 339, in dbus_fast._private.unmarshaller.Unmarshaller._read_sock_without_fds
EOFError

我不明白这是什么意思。我尝试查看systemd 中有关抑制锁的官方文档，但一无所获。如何使用 dbus_python 在 Python 中调用抑制锁Inhibit的方法org.freedesktop.login1.Manager并获取抑制锁？

python

1 个回答

  1. Best Answer

    由于某些原因，dbus-fast 默认不启用对文件描述符传输的支持。您必须将negotiate_unix_fd=True其指定为 MessageBus() 的参数才能启用此功能。

    • 1

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