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#
# Module to allow connection and socket objects to be transferred
# between processes
#
# multiprocessing/reduction.py
#
# Copyright (c) 2006-2008, R Oudkerk
# Licensed to PSF under a Contributor Agreement.
#
__all__ = ['reduce_socket', 'reduce_connection', 'send_handle', 'recv_handle']
import os
import sys
import socket
import threading
import struct
import signal
from multiprocessing import current_process
from multiprocessing.util import register_after_fork, debug, sub_debug
from multiprocessing.util import is_exiting, sub_warning
#
#
#
if not(sys.platform == 'win32' or (hasattr(socket, 'CMSG_LEN') and
hasattr(socket, 'SCM_RIGHTS'))):
raise ImportError('pickling of connections not supported')
#
# Platform specific definitions
#
if sys.platform == 'win32':
# Windows
__all__ += ['reduce_pipe_connection']
import _winapi
def send_handle(conn, handle, destination_pid):
dh = DupHandle(handle, _winapi.DUPLICATE_SAME_ACCESS, destination_pid)
conn.send(dh)
def recv_handle(conn):
return conn.recv().detach()
class DupHandle(object):
def __init__(self, handle, access, pid=None):
# duplicate handle for process with given pid
if pid is None:
pid = os.getpid()
proc = _winapi.OpenProcess(_winapi.PROCESS_DUP_HANDLE, False, pid)
try:
self._handle = _winapi.DuplicateHandle(
_winapi.GetCurrentProcess(),
handle, proc, access, False, 0)
finally:
_winapi.CloseHandle(proc)
self._access = access
self._pid = pid
def detach(self):
# retrieve handle from process which currently owns it
if self._pid == os.getpid():
return self._handle
proc = _winapi.OpenProcess(_winapi.PROCESS_DUP_HANDLE, False,
self._pid)
try:
return _winapi.DuplicateHandle(
proc, self._handle, _winapi.GetCurrentProcess(),
self._access, False, _winapi.DUPLICATE_CLOSE_SOURCE)
finally:
_winapi.CloseHandle(proc)
class DupSocket(object):
def __init__(self, sock):
new_sock = sock.dup()
def send(conn, pid):
share = new_sock.share(pid)
conn.send_bytes(share)
self._id = resource_sharer.register(send, new_sock.close)
def detach(self):
conn = resource_sharer.get_connection(self._id)
try:
share = conn.recv_bytes()
return socket.fromshare(share)
finally:
conn.close()
def reduce_socket(s):
return rebuild_socket, (DupSocket(s),)
def rebuild_socket(ds):
return ds.detach()
def reduce_connection(conn):
handle = conn.fileno()
with socket.fromfd(handle, socket.AF_INET, socket.SOCK_STREAM) as s:
ds = DupSocket(s)
return rebuild_connection, (ds, conn.readable, conn.writable)
def rebuild_connection(ds, readable, writable):
from .connection import Connection
sock = ds.detach()
return Connection(sock.detach(), readable, writable)
def reduce_pipe_connection(conn):
access = ((_winapi.FILE_GENERIC_READ if conn.readable else 0) |
(_winapi.FILE_GENERIC_WRITE if conn.writable else 0))
dh = DupHandle(conn.fileno(), access)
return rebuild_pipe_connection, (dh, conn.readable, conn.writable)
def rebuild_pipe_connection(dh, readable, writable):
from .connection import PipeConnection
handle = dh.detach()
return PipeConnection(handle, readable, writable)
else:
# Unix
# On MacOSX we should acknowledge receipt of fds -- see Issue14669
ACKNOWLEDGE = sys.platform == 'darwin'
def send_handle(conn, handle, destination_pid):
with socket.fromfd(conn.fileno(), socket.AF_UNIX, socket.SOCK_STREAM) as s:
s.sendmsg([b'x'], [(socket.SOL_SOCKET, socket.SCM_RIGHTS,
struct.pack("@i", handle))])
if ACKNOWLEDGE and conn.recv_bytes() != b'ACK':
raise RuntimeError('did not receive acknowledgement of fd')
def recv_handle(conn):
size = struct.calcsize("@i")
with socket.fromfd(conn.fileno(), socket.AF_UNIX, socket.SOCK_STREAM) as s:
msg, ancdata, flags, addr = s.recvmsg(1, socket.CMSG_LEN(size))
try:
if ACKNOWLEDGE:
conn.send_bytes(b'ACK')
cmsg_level, cmsg_type, cmsg_data = ancdata[0]
if (cmsg_level == socket.SOL_SOCKET and
cmsg_type == socket.SCM_RIGHTS):
return struct.unpack("@i", cmsg_data[:size])[0]
except (ValueError, IndexError, struct.error):
pass
raise RuntimeError('Invalid data received')
class DupFd(object):
def __init__(self, fd):
new_fd = os.dup(fd)
def send(conn, pid):
send_handle(conn, new_fd, pid)
def close():
os.close(new_fd)
self._id = resource_sharer.register(send, close)
def detach(self):
conn = resource_sharer.get_connection(self._id)
try:
return recv_handle(conn)
finally:
conn.close()
def reduce_socket(s):
df = DupFd(s.fileno())
return rebuild_socket, (df, s.family, s.type, s.proto)
def rebuild_socket(df, family, type, proto):
fd = df.detach()
s = socket.fromfd(fd, family, type, proto)
os.close(fd)
return s
def reduce_connection(conn):
df = DupFd(conn.fileno())
return rebuild_connection, (df, conn.readable, conn.writable)
def rebuild_connection(df, readable, writable):
from .connection import Connection
fd = df.detach()
return Connection(fd, readable, writable)
#
# Server which shares registered resources with clients
#
class ResourceSharer(object):
def __init__(self):
self._key = 0
self._cache = {}
self._old_locks = []
self._lock = threading.Lock()
self._listener = None
self._address = None
self._thread = None
register_after_fork(self, ResourceSharer._afterfork)
def register(self, send, close):
with self._lock:
if self._address is None:
self._start()
self._key += 1
self._cache[self._key] = (send, close)
return (self._address, self._key)
@staticmethod
def get_connection(ident):
from .connection import Client
address, key = ident
c = Client(address, authkey=current_process().authkey)
c.send((key, os.getpid()))
return c
def stop(self, timeout=None):
from .connection import Client
with self._lock:
if self._address is not None:
c = Client(self._address, authkey=current_process().authkey)
c.send(None)
c.close()
self._thread.join(timeout)
if self._thread.is_alive():
sub_warn('ResourceSharer thread did not stop when asked')
self._listener.close()
self._thread = None
self._address = None
self._listener = None
for key, (send, close) in self._cache.items():
close()
self._cache.clear()
def _afterfork(self):
for key, (send, close) in self._cache.items():
close()
self._cache.clear()
# If self._lock was locked at the time of the fork, it may be broken
# -- see issue 6721. Replace it without letting it be gc'ed.
self._old_locks.append(self._lock)
self._lock = threading.Lock()
if self._listener is not None:
self._listener.close()
self._listener = None
self._address = None
self._thread = None
def _start(self):
from .connection import Listener
assert self._listener is None
debug('starting listener and thread for sending handles')
self._listener = Listener(authkey=current_process().authkey)
self._address = self._listener.address
t = threading.Thread(target=self._serve)
t.daemon = True
t.start()
self._thread = t
def _serve(self):
if hasattr(signal, 'pthread_sigmask'):
signal.pthread_sigmask(signal.SIG_BLOCK, range(1, signal.NSIG))
while 1:
try:
conn = self._listener.accept()
msg = conn.recv()
if msg is None:
break
key, destination_pid = msg
send, close = self._cache.pop(key)
send(conn, destination_pid)
close()
conn.close()
except:
if not is_exiting():
import traceback
sub_warning(
'thread for sharing handles raised exception :\n' +
'-'*79 + '\n' + traceback.format_exc() + '-'*79
)
resource_sharer = ResourceSharer()