/usr/lib/python3.7/multiprocessing/popen_spawn_posix.py is in libpython3.7-stdlib 3.7.0~b3-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | import io
import os
from .context import reduction, set_spawning_popen
from . import popen_fork
from . import spawn
from . import util
__all__ = ['Popen']
#
# Wrapper for an fd used while launching a process
#
class _DupFd(object):
def __init__(self, fd):
self.fd = fd
def detach(self):
return self.fd
#
# Start child process using a fresh interpreter
#
class Popen(popen_fork.Popen):
method = 'spawn'
DupFd = _DupFd
def __init__(self, process_obj):
self._fds = []
super().__init__(process_obj)
def duplicate_for_child(self, fd):
self._fds.append(fd)
return fd
def _launch(self, process_obj):
from . import semaphore_tracker
tracker_fd = semaphore_tracker.getfd()
self._fds.append(tracker_fd)
prep_data = spawn.get_preparation_data(process_obj._name)
fp = io.BytesIO()
set_spawning_popen(self)
try:
reduction.dump(prep_data, fp)
reduction.dump(process_obj, fp)
finally:
set_spawning_popen(None)
parent_r = child_w = child_r = parent_w = None
try:
parent_r, child_w = os.pipe()
child_r, parent_w = os.pipe()
cmd = spawn.get_command_line(tracker_fd=tracker_fd,
pipe_handle=child_r)
self._fds.extend([child_r, child_w])
self.pid = util.spawnv_passfds(spawn.get_executable(),
cmd, self._fds)
self.sentinel = parent_r
with open(parent_w, 'wb', closefd=False) as f:
f.write(fp.getbuffer())
finally:
if parent_r is not None:
self.finalizer = util.Finalize(self, os.close, (parent_r,))
for fd in (child_r, child_w, parent_w):
if fd is not None:
os.close(fd)
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