cpython/Lib/multiprocessing/connection.py

737 lines
22 KiB
Python

#
# 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 io
import os
import sys
import pickle
import select
import socket
import struct
import errno
import time
import tempfile
import itertools
import _multiprocessing
from multiprocessing import current_process, AuthenticationError, BufferTooShort
from multiprocessing.util import get_temp_dir, Finalize, sub_debug, debug
try:
from _multiprocessing import win32
except ImportError:
if sys.platform == 'win32':
raise
win32 = None
#
#
#
BUFSIZE = 8192
# A very generous timeout when it comes to local connections...
CONNECTION_TIMEOUT = 20.
_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(), next(_mmap_counter)))
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)
#
# Connection classes
#
class _ConnectionBase:
_handle = None
def __init__(self, handle, readable=True, writable=True):
handle = handle.__index__()
if handle < 0:
raise ValueError("invalid handle")
if not readable and not writable:
raise ValueError(
"at least one of `readable` and `writable` must be True")
self._handle = handle
self._readable = readable
self._writable = writable
def __del__(self):
if self._handle is not None:
self._close()
def _check_closed(self):
if self._handle is None:
raise IOError("handle is closed")
def _check_readable(self):
if not self._readable:
raise IOError("connection is write-only")
def _check_writable(self):
if not self._writable:
raise IOError("connection is read-only")
def _bad_message_length(self):
if self._writable:
self._readable = False
else:
self.close()
raise IOError("bad message length")
@property
def closed(self):
"""True if the connection is closed"""
return self._handle is None
@property
def readable(self):
"""True if the connection is readable"""
return self._readable
@property
def writable(self):
"""True if the connection is writable"""
return self._writable
def fileno(self):
"""File descriptor or handle of the connection"""
self._check_closed()
return self._handle
def close(self):
"""Close the connection"""
if self._handle is not None:
try:
self._close()
finally:
self._handle = None
def send_bytes(self, buf, offset=0, size=None):
"""Send the bytes data from a bytes-like object"""
self._check_closed()
self._check_writable()
m = memoryview(buf)
# HACK for byte-indexing of non-bytewise buffers (e.g. array.array)
if m.itemsize > 1:
m = memoryview(bytes(m))
n = len(m)
if offset < 0:
raise ValueError("offset is negative")
if n < offset:
raise ValueError("buffer length < offset")
if size is None:
size = n - offset
elif size < 0:
raise ValueError("size is negative")
elif offset + size > n:
raise ValueError("buffer length < offset + size")
self._send_bytes(m[offset:offset + size])
def send(self, obj):
"""Send a (picklable) object"""
self._check_closed()
self._check_writable()
buf = pickle.dumps(obj, protocol=pickle.HIGHEST_PROTOCOL)
self._send_bytes(memoryview(buf))
def recv_bytes(self, maxlength=None):
"""
Receive bytes data as a bytes object.
"""
self._check_closed()
self._check_readable()
if maxlength is not None and maxlength < 0:
raise ValueError("negative maxlength")
buf = self._recv_bytes(maxlength)
if buf is None:
self._bad_message_length()
return buf.getvalue()
def recv_bytes_into(self, buf, offset=0):
"""
Receive bytes data into a writeable buffer-like object.
Return the number of bytes read.
"""
self._check_closed()
self._check_readable()
with memoryview(buf) as m:
# Get bytesize of arbitrary buffer
itemsize = m.itemsize
bytesize = itemsize * len(m)
if offset < 0:
raise ValueError("negative offset")
elif offset > bytesize:
raise ValueError("offset too large")
result = self._recv_bytes()
size = result.tell()
if bytesize < offset + size:
raise BufferTooShort(result.getvalue())
# Message can fit in dest
result.seek(0)
result.readinto(m[offset // itemsize :
(offset + size) // itemsize])
return size
def recv(self):
"""Receive a (picklable) object"""
self._check_closed()
self._check_readable()
buf = self._recv_bytes()
return pickle.loads(buf.getbuffer())
def poll(self, timeout=0.0):
"""Whether there is any input available to be read"""
self._check_closed()
self._check_readable()
if timeout < 0.0:
timeout = None
return self._poll(timeout)
if win32:
class PipeConnection(_ConnectionBase):
"""
Connection class based on a Windows named pipe.
"""
def _close(self):
win32.CloseHandle(self._handle)
def _send_bytes(self, buf):
nwritten = win32.WriteFile(self._handle, buf)
assert nwritten == len(buf)
def _recv_bytes(self, maxsize=None):
buf = io.BytesIO()
bufsize = 512
if maxsize is not None:
bufsize = min(bufsize, maxsize)
try:
firstchunk, complete = win32.ReadFile(self._handle, bufsize)
except IOError as e:
if e.errno == win32.ERROR_BROKEN_PIPE:
raise EOFError
raise
lenfirstchunk = len(firstchunk)
buf.write(firstchunk)
if complete:
return buf
navail, nleft = win32.PeekNamedPipe(self._handle)
if maxsize is not None and lenfirstchunk + nleft > maxsize:
return None
lastchunk, complete = win32.ReadFile(self._handle, nleft)
assert complete
buf.write(lastchunk)
return buf
def _poll(self, timeout):
navail, nleft = win32.PeekNamedPipe(self._handle)
if navail > 0:
return True
elif timeout == 0.0:
return False
# Setup a polling loop (translated straight from old
# pipe_connection.c)
if timeout < 0.0:
deadline = None
else:
deadline = time.time() + timeout
delay = 0.001
max_delay = 0.02
while True:
time.sleep(delay)
navail, nleft = win32.PeekNamedPipe(self._handle)
if navail > 0:
return True
if deadline and time.time() > deadline:
return False
if delay < max_delay:
delay += 0.001
class Connection(_ConnectionBase):
"""
Connection class based on an arbitrary file descriptor (Unix only), or
a socket handle (Windows).
"""
if win32:
def _close(self):
win32.closesocket(self._handle)
_write = win32.send
_read = win32.recv
else:
def _close(self):
os.close(self._handle)
_write = os.write
_read = os.read
def _send(self, buf, write=_write):
remaining = len(buf)
while True:
n = write(self._handle, buf)
remaining -= n
if remaining == 0:
break
buf = buf[n:]
def _recv(self, size, read=_read):
buf = io.BytesIO()
remaining = size
while remaining > 0:
chunk = read(self._handle, remaining)
n = len(chunk)
if n == 0:
if remaining == size:
raise EOFError
else:
raise IOError("got end of file during message")
buf.write(chunk)
remaining -= n
return buf
def _send_bytes(self, buf):
# For wire compatibility with 3.2 and lower
n = len(buf)
self._send(struct.pack("=i", len(buf)))
# The condition is necessary to avoid "broken pipe" errors
# when sending a 0-length buffer if the other end closed the pipe.
if n > 0:
self._send(buf)
def _recv_bytes(self, maxsize=None):
buf = self._recv(4)
size, = struct.unpack("=i", buf.getvalue())
if maxsize is not None and size > maxsize:
return None
return self._recv(size)
def _poll(self, timeout):
r = select.select([self._handle], [], [], timeout)[0]
return bool(r)
#
# 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()
c1 = Connection(s1.detach())
c2 = Connection(s2.detach())
else:
fd1, fd2 = os.pipe()
c1 = Connection(fd1, writable=False)
c2 = Connection(fd2, readable=False)
return c1, c2
else:
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 as e:
if e.args[0] != win32.ERROR_PIPE_CONNECTED:
raise
c1 = PipeConnection(h1, writable=duplex)
c2 = 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))
self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self._socket.bind(address)
self._socket.listen(backlog)
self._address = self._socket.getsockname()
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):
s, self._last_accepted = self._socket.accept()
fd = duplicate(s.fileno())
conn = Connection(fd)
s.close()
return conn
def close(self):
self._socket.close()
if self._unlink is not None:
self._unlink()
def SocketClient(address):
'''
Return a connection object connected to the socket given by `address`
'''
family = address_type(address)
with socket.socket( getattr(socket, family) ) as s:
t = _init_timeout()
while 1:
try:
s.connect(address)
except socket.error as e:
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 = Connection(fd)
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 as e:
if e.args[0] != win32.ERROR_PIPE_CONNECTED:
raise
return 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 as 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 PipeConnection(h)
#
# Authentication stuff
#
MESSAGE_LENGTH = 20
CHALLENGE = b'#CHALLENGE#'
WELCOME = b'#WELCOME#'
FAILURE = b'#FAILURE#'
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).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).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).encode('utf-8')
def _xml_loads(s):
(obj,), method = xmlrpclib.loads(s.decode('utf-8'))
return obj
class XmlListener(Listener):
def accept(self):
global xmlrpclib
import xmlrpc.client as xmlrpclib
obj = Listener.accept(self)
return ConnectionWrapper(obj, _xml_dumps, _xml_loads)
def XmlClient(*args, **kwds):
global xmlrpclib
import xmlrpc.client as xmlrpclib
return ConnectionWrapper(Client(*args, **kwds), _xml_dumps, _xml_loads)
# Late import because of circular import
from multiprocessing.forking import duplicate, close