Edit File: connection.py
# # A higher level module for using sockets (or Windows named pipes) # # multiprocessing/connection.py # # Copyright (c) 2006-2008, R Oudkerk # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # # 1. Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # 2. Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # 3. Neither the name of author nor the names of any contributors may be # used to endorse or promote products derived from this software # without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE # ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF # SUCH DAMAGE. # __all__ = [ 'Client', 'Listener', 'Pipe' ] import os import sys import socket import errno import time import tempfile import itertools import _multiprocessing from multiprocessing import current_process, AuthenticationError from multiprocessing.util import get_temp_dir, Finalize, sub_debug, debug from multiprocessing.forking import duplicate, close # # # BUFSIZE = 8192 # A very generous timeout when it comes to local connections... CONNECTION_TIMEOUT = 20. # The hmac module implicitly defaults to using MD5. # Support using a stronger algorithm for the challenge/response code: HMAC_DIGEST_NAME='sha256' _mmap_counter = itertools.count() default_family = 'AF_INET' families = ['AF_INET'] if hasattr(socket, 'AF_UNIX'): default_family = 'AF_UNIX' families += ['AF_UNIX'] if sys.platform == 'win32': default_family = 'AF_PIPE' families += ['AF_PIPE'] def _init_timeout(timeout=CONNECTION_TIMEOUT): return time.time() + timeout def _check_timeout(t): return time.time() > t # # # def arbitrary_address(family): ''' Return an arbitrary free address for the given family ''' if family == 'AF_INET': return ('localhost', 0) elif family == 'AF_UNIX': return tempfile.mktemp(prefix='listener-', dir=get_temp_dir()) elif family == 'AF_PIPE': return tempfile.mktemp(prefix=r'\\.\pipe\pyc-%d-%d-' % (os.getpid(), _mmap_counter.next()), dir="") else: raise ValueError('unrecognized family') def address_type(address): ''' Return the types of the address This can be 'AF_INET', 'AF_UNIX', or 'AF_PIPE' ''' if type(address) == tuple: return 'AF_INET' elif type(address) is str and address.startswith('\\\\'): return 'AF_PIPE' elif type(address) is str: return 'AF_UNIX' else: raise ValueError('address type of %r unrecognized' % address) # # Public functions # class Listener(object): ''' Returns a listener object. This is a wrapper for a bound socket which is 'listening' for connections, or for a Windows named pipe. ''' def __init__(self, address=None, family=None, backlog=1, authkey=None): family = family or (address and address_type(address)) \ or default_family address = address or arbitrary_address(family) if family == 'AF_PIPE': self._listener = PipeListener(address, backlog) else: self._listener = SocketListener(address, family, backlog) if authkey is not None and not isinstance(authkey, bytes): raise TypeError, 'authkey should be a byte string' self._authkey = authkey def accept(self): ''' Accept a connection on the bound socket or named pipe of `self`. Returns a `Connection` object. ''' c = self._listener.accept() if self._authkey: deliver_challenge(c, self._authkey) answer_challenge(c, self._authkey) return c def close(self): ''' Close the bound socket or named pipe of `self`. ''' return self._listener.close() address = property(lambda self: self._listener._address) last_accepted = property(lambda self: self._listener._last_accepted) def Client(address, family=None, authkey=None): ''' Returns a connection to the address of a `Listener` ''' family = family or address_type(address) if family == 'AF_PIPE': c = PipeClient(address) else: c = SocketClient(address) if authkey is not None and not isinstance(authkey, bytes): raise TypeError, 'authkey should be a byte string' if authkey is not None: answer_challenge(c, authkey) deliver_challenge(c, authkey) return c if sys.platform != 'win32': def Pipe(duplex=True): ''' Returns pair of connection objects at either end of a pipe ''' if duplex: s1, s2 = socket.socketpair() s1.setblocking(True) s2.setblocking(True) c1 = _multiprocessing.Connection(os.dup(s1.fileno())) c2 = _multiprocessing.Connection(os.dup(s2.fileno())) s1.close() s2.close() else: fd1, fd2 = os.pipe() c1 = _multiprocessing.Connection(fd1, writable=False) c2 = _multiprocessing.Connection(fd2, readable=False) return c1, c2 else: from _multiprocessing import win32 def Pipe(duplex=True): ''' Returns pair of connection objects at either end of a pipe ''' address = arbitrary_address('AF_PIPE') if duplex: openmode = win32.PIPE_ACCESS_DUPLEX access = win32.GENERIC_READ | win32.GENERIC_WRITE obsize, ibsize = BUFSIZE, BUFSIZE else: openmode = win32.PIPE_ACCESS_INBOUND access = win32.GENERIC_WRITE obsize, ibsize = 0, BUFSIZE h1 = win32.CreateNamedPipe( address, openmode, win32.PIPE_TYPE_MESSAGE | win32.PIPE_READMODE_MESSAGE | win32.PIPE_WAIT, 1, obsize, ibsize, win32.NMPWAIT_WAIT_FOREVER, win32.NULL ) h2 = win32.CreateFile( address, access, 0, win32.NULL, win32.OPEN_EXISTING, 0, win32.NULL ) win32.SetNamedPipeHandleState( h2, win32.PIPE_READMODE_MESSAGE, None, None ) try: win32.ConnectNamedPipe(h1, win32.NULL) except WindowsError, e: if e.args[0] != win32.ERROR_PIPE_CONNECTED: raise c1 = _multiprocessing.PipeConnection(h1, writable=duplex) c2 = _multiprocessing.PipeConnection(h2, readable=duplex) return c1, c2 # # Definitions for connections based on sockets # class SocketListener(object): ''' Representation of a socket which is bound to an address and listening ''' def __init__(self, address, family, backlog=1): self._socket = socket.socket(getattr(socket, family)) try: self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) self._socket.setblocking(True) self._socket.bind(address) self._socket.listen(backlog) self._address = self._socket.getsockname() except socket.error: self._socket.close() raise self._family = family self._last_accepted = None if family == 'AF_UNIX': self._unlink = Finalize( self, os.unlink, args=(address,), exitpriority=0 ) else: self._unlink = None def accept(self): while True: try: s, self._last_accepted = self._socket.accept() except socket.error as e: if e.args[0] != errno.EINTR: raise else: break s.setblocking(True) fd = duplicate(s.fileno()) conn = _multiprocessing.Connection(fd) s.close() return conn def close(self): try: self._socket.close() finally: unlink = self._unlink if unlink is not None: self._unlink = None unlink() def SocketClient(address): ''' Return a connection object connected to the socket given by `address` ''' family = getattr(socket, address_type(address)) t = _init_timeout() while 1: s = socket.socket(family) s.setblocking(True) try: s.connect(address) except socket.error, e: s.close() if e.args[0] != errno.ECONNREFUSED or _check_timeout(t): debug('failed to connect to address %s', address) raise time.sleep(0.01) else: break else: raise fd = duplicate(s.fileno()) conn = _multiprocessing.Connection(fd) s.close() return conn # # Definitions for connections based on named pipes # if sys.platform == 'win32': class PipeListener(object): ''' Representation of a named pipe ''' def __init__(self, address, backlog=None): self._address = address handle = win32.CreateNamedPipe( address, win32.PIPE_ACCESS_DUPLEX, win32.PIPE_TYPE_MESSAGE | win32.PIPE_READMODE_MESSAGE | win32.PIPE_WAIT, win32.PIPE_UNLIMITED_INSTANCES, BUFSIZE, BUFSIZE, win32.NMPWAIT_WAIT_FOREVER, win32.NULL ) self._handle_queue = [handle] self._last_accepted = None sub_debug('listener created with address=%r', self._address) self.close = Finalize( self, PipeListener._finalize_pipe_listener, args=(self._handle_queue, self._address), exitpriority=0 ) def accept(self): newhandle = win32.CreateNamedPipe( self._address, win32.PIPE_ACCESS_DUPLEX, win32.PIPE_TYPE_MESSAGE | win32.PIPE_READMODE_MESSAGE | win32.PIPE_WAIT, win32.PIPE_UNLIMITED_INSTANCES, BUFSIZE, BUFSIZE, win32.NMPWAIT_WAIT_FOREVER, win32.NULL ) self._handle_queue.append(newhandle) handle = self._handle_queue.pop(0) try: win32.ConnectNamedPipe(handle, win32.NULL) except WindowsError, e: # ERROR_NO_DATA can occur if a client has already connected, # written data and then disconnected -- see Issue 14725. if e.args[0] not in (win32.ERROR_PIPE_CONNECTED, win32.ERROR_NO_DATA): raise return _multiprocessing.PipeConnection(handle) @staticmethod def _finalize_pipe_listener(queue, address): sub_debug('closing listener with address=%r', address) for handle in queue: close(handle) def PipeClient(address): ''' Return a connection object connected to the pipe given by `address` ''' t = _init_timeout() while 1: try: win32.WaitNamedPipe(address, 1000) h = win32.CreateFile( address, win32.GENERIC_READ | win32.GENERIC_WRITE, 0, win32.NULL, win32.OPEN_EXISTING, 0, win32.NULL ) except WindowsError, e: if e.args[0] not in (win32.ERROR_SEM_TIMEOUT, win32.ERROR_PIPE_BUSY) or _check_timeout(t): raise else: break else: raise win32.SetNamedPipeHandleState( h, win32.PIPE_READMODE_MESSAGE, None, None ) return _multiprocessing.PipeConnection(h) # # Authentication stuff # MESSAGE_LENGTH = 20 CHALLENGE = b'#CHALLENGE#' WELCOME = b'#WELCOME#' FAILURE = b'#FAILURE#' def get_digestmod_for_hmac(): import hashlib return getattr(hashlib, HMAC_DIGEST_NAME) def deliver_challenge(connection, authkey): import hmac assert isinstance(authkey, bytes) message = os.urandom(MESSAGE_LENGTH) connection.send_bytes(CHALLENGE + message) digest = hmac.new(authkey, message, get_digestmod_for_hmac()).digest() response = connection.recv_bytes(256) # reject large message if response == digest: connection.send_bytes(WELCOME) else: connection.send_bytes(FAILURE) raise AuthenticationError('digest received was wrong') def answer_challenge(connection, authkey): import hmac assert isinstance(authkey, bytes) message = connection.recv_bytes(256) # reject large message assert message[:len(CHALLENGE)] == CHALLENGE, 'message = %r' % message message = message[len(CHALLENGE):] digest = hmac.new(authkey, message, get_digestmod_for_hmac()).digest() connection.send_bytes(digest) response = connection.recv_bytes(256) # reject large message if response != WELCOME: raise AuthenticationError('digest sent was rejected') # # Support for using xmlrpclib for serialization # class ConnectionWrapper(object): def __init__(self, conn, dumps, loads): self._conn = conn self._dumps = dumps self._loads = loads for attr in ('fileno', 'close', 'poll', 'recv_bytes', 'send_bytes'): obj = getattr(conn, attr) setattr(self, attr, obj) def send(self, obj): s = self._dumps(obj) self._conn.send_bytes(s) def recv(self): s = self._conn.recv_bytes() return self._loads(s) def _xml_dumps(obj): return xmlrpclib.dumps((obj,), None, None, None, 1) def _xml_loads(s): (obj,), method = xmlrpclib.loads(s) return obj class XmlListener(Listener): def accept(self): global xmlrpclib import xmlrpclib obj = Listener.accept(self) return ConnectionWrapper(obj, _xml_dumps, _xml_loads) def XmlClient(*args, **kwds): global xmlrpclib import xmlrpclib return ConnectionWrapper(Client(*args, **kwds), _xml_dumps, _xml_loads)
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