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annotate CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/lib/python3.8/multiprocessing/resource_sharer.py @ 69:33d812a61356

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planemo upload commit 2e9511a184a1ca667c7be0c6321a36dc4e3d116d
author jpayne
date Tue, 18 Mar 2025 17:55:14 -0400
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jpayne@69 1 #
jpayne@69 2 # We use a background thread for sharing fds on Unix, and for sharing sockets on
jpayne@69 3 # Windows.
jpayne@69 4 #
jpayne@69 5 # A client which wants to pickle a resource registers it with the resource
jpayne@69 6 # sharer and gets an identifier in return. The unpickling process will connect
jpayne@69 7 # to the resource sharer, sends the identifier and its pid, and then receives
jpayne@69 8 # the resource.
jpayne@69 9 #
jpayne@69 10
jpayne@69 11 import os
jpayne@69 12 import signal
jpayne@69 13 import socket
jpayne@69 14 import sys
jpayne@69 15 import threading
jpayne@69 16
jpayne@69 17 from . import process
jpayne@69 18 from .context import reduction
jpayne@69 19 from . import util
jpayne@69 20
jpayne@69 21 __all__ = ['stop']
jpayne@69 22
jpayne@69 23
jpayne@69 24 if sys.platform == 'win32':
jpayne@69 25 __all__ += ['DupSocket']
jpayne@69 26
jpayne@69 27 class DupSocket(object):
jpayne@69 28 '''Picklable wrapper for a socket.'''
jpayne@69 29 def __init__(self, sock):
jpayne@69 30 new_sock = sock.dup()
jpayne@69 31 def send(conn, pid):
jpayne@69 32 share = new_sock.share(pid)
jpayne@69 33 conn.send_bytes(share)
jpayne@69 34 self._id = _resource_sharer.register(send, new_sock.close)
jpayne@69 35
jpayne@69 36 def detach(self):
jpayne@69 37 '''Get the socket. This should only be called once.'''
jpayne@69 38 with _resource_sharer.get_connection(self._id) as conn:
jpayne@69 39 share = conn.recv_bytes()
jpayne@69 40 return socket.fromshare(share)
jpayne@69 41
jpayne@69 42 else:
jpayne@69 43 __all__ += ['DupFd']
jpayne@69 44
jpayne@69 45 class DupFd(object):
jpayne@69 46 '''Wrapper for fd which can be used at any time.'''
jpayne@69 47 def __init__(self, fd):
jpayne@69 48 new_fd = os.dup(fd)
jpayne@69 49 def send(conn, pid):
jpayne@69 50 reduction.send_handle(conn, new_fd, pid)
jpayne@69 51 def close():
jpayne@69 52 os.close(new_fd)
jpayne@69 53 self._id = _resource_sharer.register(send, close)
jpayne@69 54
jpayne@69 55 def detach(self):
jpayne@69 56 '''Get the fd. This should only be called once.'''
jpayne@69 57 with _resource_sharer.get_connection(self._id) as conn:
jpayne@69 58 return reduction.recv_handle(conn)
jpayne@69 59
jpayne@69 60
jpayne@69 61 class _ResourceSharer(object):
jpayne@69 62 '''Manager for resources using background thread.'''
jpayne@69 63 def __init__(self):
jpayne@69 64 self._key = 0
jpayne@69 65 self._cache = {}
jpayne@69 66 self._old_locks = []
jpayne@69 67 self._lock = threading.Lock()
jpayne@69 68 self._listener = None
jpayne@69 69 self._address = None
jpayne@69 70 self._thread = None
jpayne@69 71 util.register_after_fork(self, _ResourceSharer._afterfork)
jpayne@69 72
jpayne@69 73 def register(self, send, close):
jpayne@69 74 '''Register resource, returning an identifier.'''
jpayne@69 75 with self._lock:
jpayne@69 76 if self._address is None:
jpayne@69 77 self._start()
jpayne@69 78 self._key += 1
jpayne@69 79 self._cache[self._key] = (send, close)
jpayne@69 80 return (self._address, self._key)
jpayne@69 81
jpayne@69 82 @staticmethod
jpayne@69 83 def get_connection(ident):
jpayne@69 84 '''Return connection from which to receive identified resource.'''
jpayne@69 85 from .connection import Client
jpayne@69 86 address, key = ident
jpayne@69 87 c = Client(address, authkey=process.current_process().authkey)
jpayne@69 88 c.send((key, os.getpid()))
jpayne@69 89 return c
jpayne@69 90
jpayne@69 91 def stop(self, timeout=None):
jpayne@69 92 '''Stop the background thread and clear registered resources.'''
jpayne@69 93 from .connection import Client
jpayne@69 94 with self._lock:
jpayne@69 95 if self._address is not None:
jpayne@69 96 c = Client(self._address,
jpayne@69 97 authkey=process.current_process().authkey)
jpayne@69 98 c.send(None)
jpayne@69 99 c.close()
jpayne@69 100 self._thread.join(timeout)
jpayne@69 101 if self._thread.is_alive():
jpayne@69 102 util.sub_warning('_ResourceSharer thread did '
jpayne@69 103 'not stop when asked')
jpayne@69 104 self._listener.close()
jpayne@69 105 self._thread = None
jpayne@69 106 self._address = None
jpayne@69 107 self._listener = None
jpayne@69 108 for key, (send, close) in self._cache.items():
jpayne@69 109 close()
jpayne@69 110 self._cache.clear()
jpayne@69 111
jpayne@69 112 def _afterfork(self):
jpayne@69 113 for key, (send, close) in self._cache.items():
jpayne@69 114 close()
jpayne@69 115 self._cache.clear()
jpayne@69 116 # If self._lock was locked at the time of the fork, it may be broken
jpayne@69 117 # -- see issue 6721. Replace it without letting it be gc'ed.
jpayne@69 118 self._old_locks.append(self._lock)
jpayne@69 119 self._lock = threading.Lock()
jpayne@69 120 if self._listener is not None:
jpayne@69 121 self._listener.close()
jpayne@69 122 self._listener = None
jpayne@69 123 self._address = None
jpayne@69 124 self._thread = None
jpayne@69 125
jpayne@69 126 def _start(self):
jpayne@69 127 from .connection import Listener
jpayne@69 128 assert self._listener is None, "Already have Listener"
jpayne@69 129 util.debug('starting listener and thread for sending handles')
jpayne@69 130 self._listener = Listener(authkey=process.current_process().authkey)
jpayne@69 131 self._address = self._listener.address
jpayne@69 132 t = threading.Thread(target=self._serve)
jpayne@69 133 t.daemon = True
jpayne@69 134 t.start()
jpayne@69 135 self._thread = t
jpayne@69 136
jpayne@69 137 def _serve(self):
jpayne@69 138 if hasattr(signal, 'pthread_sigmask'):
jpayne@69 139 signal.pthread_sigmask(signal.SIG_BLOCK, signal.valid_signals())
jpayne@69 140 while 1:
jpayne@69 141 try:
jpayne@69 142 with self._listener.accept() as conn:
jpayne@69 143 msg = conn.recv()
jpayne@69 144 if msg is None:
jpayne@69 145 break
jpayne@69 146 key, destination_pid = msg
jpayne@69 147 send, close = self._cache.pop(key)
jpayne@69 148 try:
jpayne@69 149 send(conn, destination_pid)
jpayne@69 150 finally:
jpayne@69 151 close()
jpayne@69 152 except:
jpayne@69 153 if not util.is_exiting():
jpayne@69 154 sys.excepthook(*sys.exc_info())
jpayne@69 155
jpayne@69 156
jpayne@69 157 _resource_sharer = _ResourceSharer()
jpayne@69 158 stop = _resource_sharer.stop