Question

我有一个以root身份运行的进程，需要关闭线程才能以各种用户身份运行。这部分工作正常，但我需要一种在子进程和父进程之间进行通信的方法。

当我尝试将multiprocessing.Manager（）与一些列表，字典，锁定，队列等一起使用时，它总是在权限降低的进程上有权限被拒绝错误。

有没有办法授予用户访问权限或PID来修复此问题？

表示我遇到的内容的基本代码（以root身份运行）：

#!/usr/bin/env python
import multiprocessing, os
manager = multiprocessing.Manager()
problematic_list = manager.list()
os.setuid(43121) # or whatever your user is
problematic_list.append('anything')

结果：

root@liberator:/home/bscable# python asd.py
Traceback (most recent call last):
  File "asd.py", line 8, in <module>
    problematic_list.append('anything')
  File "<string>", line 2, in append
  File "/usr/lib/python2.7/multiprocessing/managers.py", line 755, in _callmethod
    self._connect()
  File "/usr/lib/python2.7/multiprocessing/managers.py", line 742, in _connect
    conn = self._Client(self._token.address, authkey=self._authkey)
  File "/usr/lib/python2.7/multiprocessing/connection.py", line 169, in Client
    c = SocketClient(address)
  File "/usr/lib/python2.7/multiprocessing/connection.py", line 293, in SocketClient
    s.connect(address)
  File "/usr/lib/python2.7/socket.py", line 224, in meth
    return getattr(self._sock,name)(*args)
socket.error: [Errno 13] Permission denied
Traceback (most recent call last):
  File "/usr/lib/python2.7/multiprocessing/util.py", line 261, in _run_finalizers
    finalizer()
  File "/usr/lib/python2.7/multiprocessing/util.py", line 200, in __call__
    res = self._callback(*self._args, **self._kwargs)
  File "/usr/lib/python2.7/multiprocessing/managers.py", line 625, in _finalize_manager
    process.terminate()
  File "/usr/lib/python2.7/multiprocessing/process.py", line 137, in terminate
    self._popen.terminate()
  File "/usr/lib/python2.7/multiprocessing/forking.py", line 165, in terminate
    os.kill(self.pid, signal.SIGTERM)
OSError: [Errno 1] Operation not permitted

第一个例外似乎是重要的例外。

Answer 1

Python（至少2.6）使用UNIX套接字进行通信，如下所示：

/tmp/pymp-eGnU6a/listener-BTHJ0E

我们可以抓住该路径并更改其权限，如下所示：

#!/usr/bin/env python
import multiprocessing, os, grp, pwd
manager = multiprocessing.Manager()
problematic_list = manager.list()

fullname = manager._address
dirname = os.path.dirname(fullname)

gid = grp.getgrnam('some_group').gr_gid
uid = pwd.getpwnam('root').pw_uid # should always be 0, but you never know

os.chown(dirname, uid, gid)
os.chmod(dirname, 0770)

os.chown(fullname, uid, gid)
os.chmod(fullname, 0770)

os.setgid(gid)
os.setuid(43121) # or whatever your user is
problematic_list.append('anything')

对多个用户使用multiprocessing.Manager（）会产生权限被拒绝

1 个答案: