75 lines
2.2 KiB
Python
75 lines
2.2 KiB
Python
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import io
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import os
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from .context import reduction, set_spawning_popen
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if not reduction.HAVE_SEND_HANDLE:
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raise ImportError('No support for sending fds between processes')
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from . import forkserver
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from . import popen_fork
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from . import spawn
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from . import util
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__all__ = ['Popen']
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#
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# Wrapper for an fd used while launching a process
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#
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class _DupFd(object):
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def __init__(self, ind):
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self.ind = ind
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def detach(self):
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return forkserver.get_inherited_fds()[self.ind]
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#
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# Start child process using a server process
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#
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class Popen(popen_fork.Popen):
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method = 'forkserver'
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DupFd = _DupFd
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def __init__(self, process_obj):
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self._fds = []
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super().__init__(process_obj)
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def duplicate_for_child(self, fd):
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self._fds.append(fd)
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return len(self._fds) - 1
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def _launch(self, process_obj):
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prep_data = spawn.get_preparation_data(process_obj._name)
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buf = io.BytesIO()
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set_spawning_popen(self)
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try:
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reduction.dump(prep_data, buf)
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reduction.dump(process_obj, buf)
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finally:
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set_spawning_popen(None)
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self.sentinel, w = forkserver.connect_to_new_process(self._fds)
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# Keep a duplicate of the data pipe's write end as a sentinel of the
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# parent process used by the child process.
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_parent_w = os.dup(w)
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self.finalizer = util.Finalize(self, util.close_fds,
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(_parent_w, self.sentinel))
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with open(w, 'wb', closefd=True) as f:
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f.write(buf.getbuffer())
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self.pid = forkserver.read_signed(self.sentinel)
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def poll(self, flag=os.WNOHANG):
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if self.returncode is None:
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from multiprocessing.connection import wait
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timeout = 0 if flag == os.WNOHANG else None
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if not wait([self.sentinel], timeout):
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return None
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try:
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self.returncode = forkserver.read_signed(self.sentinel)
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except (OSError, EOFError):
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# This should not happen usually, but perhaps the forkserver
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# process itself got killed
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self.returncode = 255
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return self.returncode
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