• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1import os
2import signal
3
4from . import util
5
6__all__ = ['Popen']
7
8#
9# Start child process using fork
10#
11
12class Popen(object):
13    method = 'fork'
14
15    def __init__(self, process_obj):
16        util._flush_std_streams()
17        self.returncode = None
18        self.finalizer = None
19        self._launch(process_obj)
20
21    def duplicate_for_child(self, fd):
22        return fd
23
24    def poll(self, flag=os.WNOHANG):
25        if self.returncode is None:
26            try:
27                pid, sts = os.waitpid(self.pid, flag)
28            except OSError:
29                # Child process not yet created. See #1731717
30                # e.errno == errno.ECHILD == 10
31                return None
32            if pid == self.pid:
33                self.returncode = os.waitstatus_to_exitcode(sts)
34        return self.returncode
35
36    def wait(self, timeout=None):
37        if self.returncode is None:
38            if timeout is not None:
39                from multiprocessing.connection import wait
40                if not wait([self.sentinel], timeout):
41                    return None
42            # This shouldn't block if wait() returned successfully.
43            return self.poll(os.WNOHANG if timeout == 0.0 else 0)
44        return self.returncode
45
46    def _send_signal(self, sig):
47        if self.returncode is None:
48            try:
49                os.kill(self.pid, sig)
50            except ProcessLookupError:
51                pass
52            except OSError:
53                if self.wait(timeout=0.1) is None:
54                    raise
55
56    def terminate(self):
57        self._send_signal(signal.SIGTERM)
58
59    def kill(self):
60        self._send_signal(signal.SIGKILL)
61
62    def _launch(self, process_obj):
63        code = 1
64        parent_r, child_w = os.pipe()
65        child_r, parent_w = os.pipe()
66        self.pid = os.fork()
67        if self.pid == 0:
68            try:
69                os.close(parent_r)
70                os.close(parent_w)
71                code = process_obj._bootstrap(parent_sentinel=child_r)
72            finally:
73                os._exit(code)
74        else:
75            os.close(child_w)
76            os.close(child_r)
77            self.finalizer = util.Finalize(self, util.close_fds,
78                                           (parent_r, parent_w,))
79            self.sentinel = parent_r
80
81    def close(self):
82        if self.finalizer is not None:
83            self.finalizer()
84