• 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 as e:
29                # Child process not yet created. See #1731717
30                # e.errno == errno.ECHILD == 10
31                return None
32            if pid == self.pid:
33                if os.WIFSIGNALED(sts):
34                    self.returncode = -os.WTERMSIG(sts)
35                else:
36                    assert os.WIFEXITED(sts), "Status is {:n}".format(sts)
37                    self.returncode = os.WEXITSTATUS(sts)
38        return self.returncode
39
40    def wait(self, timeout=None):
41        if self.returncode is None:
42            if timeout is not None:
43                from multiprocessing.connection import wait
44                if not wait([self.sentinel], timeout):
45                    return None
46            # This shouldn't block if wait() returned successfully.
47            return self.poll(os.WNOHANG if timeout == 0.0 else 0)
48        return self.returncode
49
50    def _send_signal(self, sig):
51        if self.returncode is None:
52            try:
53                os.kill(self.pid, sig)
54            except ProcessLookupError:
55                pass
56            except OSError:
57                if self.wait(timeout=0.1) is None:
58                    raise
59
60    def terminate(self):
61        self._send_signal(signal.SIGTERM)
62
63    def kill(self):
64        self._send_signal(signal.SIGKILL)
65
66    def _launch(self, process_obj):
67        code = 1
68        parent_r, child_w = os.pipe()
69        child_r, parent_w = os.pipe()
70        self.pid = os.fork()
71        if self.pid == 0:
72            try:
73                os.close(parent_r)
74                os.close(parent_w)
75                code = process_obj._bootstrap(parent_sentinel=child_r)
76            finally:
77                os._exit(code)
78        else:
79            os.close(child_w)
80            os.close(child_r)
81            self.finalizer = util.Finalize(self, util.close_fds,
82                                           (parent_r, parent_w,))
83            self.sentinel = parent_r
84
85    def close(self):
86        if self.finalizer is not None:
87            self.finalizer()
88