popen_fork.py 2.5 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
import os
import signal

from . import util

__all__ = ['Popen']

#
# Start child process using fork
#

class Popen(object):
    method = 'fork'

    def __init__(self, process_obj):
        util._flush_std_streams()
        self.returncode = None
        self.finalizer = None
        self._launch(process_obj)

    def duplicate_for_child(self, fd):
        return fd

    def poll(self, flag=os.WNOHANG):
        if self.returncode is None:
            try:
                pid, sts = os.waitpid(self.pid, flag)
            except OSError as e:
                # Child process not yet created. See #1731717
                # e.errno == errno.ECHILD == 10
                return None
            if pid == self.pid:
                if os.WIFSIGNALED(sts):
                    self.returncode = -os.WTERMSIG(sts)
                else:
                    assert os.WIFEXITED(sts), "Status is {:n}".format(sts)
                    self.returncode = os.WEXITSTATUS(sts)
        return self.returncode

    def wait(self, timeout=None):
        if self.returncode is None:
            if timeout is not None:
                from multiprocess.connection import wait
                if not wait([self.sentinel], timeout):
                    return None
            # This shouldn't block if wait() returned successfully.
            return self.poll(os.WNOHANG if timeout == 0.0 else 0)
        return self.returncode

    def _send_signal(self, sig):
        if self.returncode is None:
            try:
                os.kill(self.pid, sig)
            except ProcessLookupError:
                pass
            except OSError:
                if self.wait(timeout=0.1) is None:
                    raise

    def terminate(self):
        self._send_signal(signal.SIGTERM)

    def kill(self):
        self._send_signal(signal.SIGKILL)

    def _launch(self, process_obj):
        code = 1
        parent_r, child_w = os.pipe()
        child_r, parent_w = os.pipe()
        self.pid = os.fork()
        if self.pid == 0:
            try:
                os.close(parent_r)
                os.close(parent_w)
                code = process_obj._bootstrap(parent_sentinel=child_r)
            finally:
                os._exit(code)
        else:
            os.close(child_w)
            os.close(child_r)
            self.finalizer = util.Finalize(self, util.close_fds,
                                           (parent_r, parent_w,))
            self.sentinel = parent_r

    def close(self):
        if self.finalizer is not None:
            self.finalizer()