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#
# 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)