Viewing file:  popen_fork.py (2.51 KB) -rw-r--r--
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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 multiprocessing.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()
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