cpython/Lib/asyncio/proactor_events.py
Victor Stinner 231b404cb0 Issue #22560: New SSL implementation based on ssl.MemoryBIO
The new SSL implementation is based on the new ssl.MemoryBIO which is only
available on Python 3.5. On Python 3.4 and older, the legacy SSL implementation
(using SSL_write, SSL_read, etc.) is used. The proactor event loop only
supports the new implementation.

The new asyncio.sslproto module adds _SSLPipe, SSLProtocol and
_SSLProtocolTransport classes. _SSLPipe allows to "wrap" or "unwrap" a socket
(switch between cleartext and SSL/TLS).

Patch written by Antoine Pitrou. sslproto.py is based on gruvi/ssl.py of the
gruvi project written by Geert Jansen.

This change adds SSL support to ProactorEventLoop on Python 3.5 and newer!

It becomes also possible to implement STARTTTLS: switch a cleartext socket to
SSL.
2015-01-14 00:19:09 +01:00

526 lines
19 KiB
Python

"""Event loop using a proactor and related classes.
A proactor is a "notify-on-completion" multiplexer. Currently a
proactor is only implemented on Windows with IOCP.
"""
__all__ = ['BaseProactorEventLoop']
import socket
from . import base_events
from . import constants
from . import futures
from . import sslproto
from . import transports
from .log import logger
class _ProactorBasePipeTransport(transports._FlowControlMixin,
transports.BaseTransport):
"""Base class for pipe and socket transports."""
def __init__(self, loop, sock, protocol, waiter=None,
extra=None, server=None):
super().__init__(extra, loop)
self._set_extra(sock)
self._sock = sock
self._protocol = protocol
self._server = server
self._buffer = None # None or bytearray.
self._read_fut = None
self._write_fut = None
self._pending_write = 0
self._conn_lost = 0
self._closing = False # Set when close() called.
self._eof_written = False
if self._server is not None:
self._server._attach()
self._loop.call_soon(self._protocol.connection_made, self)
if waiter is not None:
# wait until protocol.connection_made() has been called
self._loop.call_soon(waiter._set_result_unless_cancelled, None)
def __repr__(self):
info = [self.__class__.__name__]
fd = self._sock.fileno()
if fd < 0:
info.append('closed')
elif self._closing:
info.append('closing')
info.append('fd=%s' % fd)
if self._read_fut is not None:
info.append('read=%s' % self._read_fut)
if self._write_fut is not None:
info.append("write=%r" % self._write_fut)
if self._buffer:
bufsize = len(self._buffer)
info.append('write_bufsize=%s' % bufsize)
if self._eof_written:
info.append('EOF written')
return '<%s>' % ' '.join(info)
def _set_extra(self, sock):
self._extra['pipe'] = sock
def close(self):
if self._closing:
return
self._closing = True
self._conn_lost += 1
if not self._buffer and self._write_fut is None:
self._loop.call_soon(self._call_connection_lost, None)
if self._read_fut is not None:
self._read_fut.cancel()
def _fatal_error(self, exc, message='Fatal error on pipe transport'):
if isinstance(exc, (BrokenPipeError, ConnectionResetError)):
if self._loop.get_debug():
logger.debug("%r: %s", self, message, exc_info=True)
else:
self._loop.call_exception_handler({
'message': message,
'exception': exc,
'transport': self,
'protocol': self._protocol,
})
self._force_close(exc)
def _force_close(self, exc):
if self._closing:
return
self._closing = True
self._conn_lost += 1
if self._write_fut:
self._write_fut.cancel()
if self._read_fut:
self._read_fut.cancel()
self._write_fut = self._read_fut = None
self._pending_write = 0
self._buffer = None
self._loop.call_soon(self._call_connection_lost, exc)
def _call_connection_lost(self, exc):
try:
self._protocol.connection_lost(exc)
finally:
# XXX If there is a pending overlapped read on the other
# end then it may fail with ERROR_NETNAME_DELETED if we
# just close our end. First calling shutdown() seems to
# cure it, but maybe using DisconnectEx() would be better.
if hasattr(self._sock, 'shutdown'):
self._sock.shutdown(socket.SHUT_RDWR)
self._sock.close()
server = self._server
if server is not None:
server._detach()
self._server = None
def get_write_buffer_size(self):
size = self._pending_write
if self._buffer is not None:
size += len(self._buffer)
return size
class _ProactorReadPipeTransport(_ProactorBasePipeTransport,
transports.ReadTransport):
"""Transport for read pipes."""
def __init__(self, loop, sock, protocol, waiter=None,
extra=None, server=None):
super().__init__(loop, sock, protocol, waiter, extra, server)
self._paused = False
self._loop.call_soon(self._loop_reading)
def pause_reading(self):
if self._closing:
raise RuntimeError('Cannot pause_reading() when closing')
if self._paused:
raise RuntimeError('Already paused')
self._paused = True
if self._loop.get_debug():
logger.debug("%r pauses reading", self)
def resume_reading(self):
if not self._paused:
raise RuntimeError('Not paused')
self._paused = False
if self._closing:
return
self._loop.call_soon(self._loop_reading, self._read_fut)
if self._loop.get_debug():
logger.debug("%r resumes reading", self)
def _loop_reading(self, fut=None):
if self._paused:
return
data = None
try:
if fut is not None:
assert self._read_fut is fut or (self._read_fut is None and
self._closing)
self._read_fut = None
data = fut.result() # deliver data later in "finally" clause
if self._closing:
# since close() has been called we ignore any read data
data = None
return
if data == b'':
# we got end-of-file so no need to reschedule a new read
return
# reschedule a new read
self._read_fut = self._loop._proactor.recv(self._sock, 4096)
except ConnectionAbortedError as exc:
if not self._closing:
self._fatal_error(exc, 'Fatal read error on pipe transport')
elif self._loop.get_debug():
logger.debug("Read error on pipe transport while closing",
exc_info=True)
except ConnectionResetError as exc:
self._force_close(exc)
except OSError as exc:
self._fatal_error(exc, 'Fatal read error on pipe transport')
except futures.CancelledError:
if not self._closing:
raise
else:
self._read_fut.add_done_callback(self._loop_reading)
finally:
if data:
self._protocol.data_received(data)
elif data is not None:
if self._loop.get_debug():
logger.debug("%r received EOF", self)
keep_open = self._protocol.eof_received()
if not keep_open:
self.close()
class _ProactorBaseWritePipeTransport(_ProactorBasePipeTransport,
transports.WriteTransport):
"""Transport for write pipes."""
def write(self, data):
if not isinstance(data, (bytes, bytearray, memoryview)):
raise TypeError('data argument must be byte-ish (%r)',
type(data))
if self._eof_written:
raise RuntimeError('write_eof() already called')
if not data:
return
if self._conn_lost:
if self._conn_lost >= constants.LOG_THRESHOLD_FOR_CONNLOST_WRITES:
logger.warning('socket.send() raised exception.')
self._conn_lost += 1
return
# Observable states:
# 1. IDLE: _write_fut and _buffer both None
# 2. WRITING: _write_fut set; _buffer None
# 3. BACKED UP: _write_fut set; _buffer a bytearray
# We always copy the data, so the caller can't modify it
# while we're still waiting for the I/O to happen.
if self._write_fut is None: # IDLE -> WRITING
assert self._buffer is None
# Pass a copy, except if it's already immutable.
self._loop_writing(data=bytes(data))
elif not self._buffer: # WRITING -> BACKED UP
# Make a mutable copy which we can extend.
self._buffer = bytearray(data)
self._maybe_pause_protocol()
else: # BACKED UP
# Append to buffer (also copies).
self._buffer.extend(data)
self._maybe_pause_protocol()
def _loop_writing(self, f=None, data=None):
try:
assert f is self._write_fut
self._write_fut = None
self._pending_write = 0
if f:
f.result()
if data is None:
data = self._buffer
self._buffer = None
if not data:
if self._closing:
self._loop.call_soon(self._call_connection_lost, None)
if self._eof_written:
self._sock.shutdown(socket.SHUT_WR)
# Now that we've reduced the buffer size, tell the
# protocol to resume writing if it was paused. Note that
# we do this last since the callback is called immediately
# and it may add more data to the buffer (even causing the
# protocol to be paused again).
self._maybe_resume_protocol()
else:
self._write_fut = self._loop._proactor.send(self._sock, data)
if not self._write_fut.done():
assert self._pending_write == 0
self._pending_write = len(data)
self._write_fut.add_done_callback(self._loop_writing)
self._maybe_pause_protocol()
else:
self._write_fut.add_done_callback(self._loop_writing)
except ConnectionResetError as exc:
self._force_close(exc)
except OSError as exc:
self._fatal_error(exc, 'Fatal write error on pipe transport')
def can_write_eof(self):
return True
def write_eof(self):
self.close()
def abort(self):
self._force_close(None)
class _ProactorWritePipeTransport(_ProactorBaseWritePipeTransport):
def __init__(self, *args, **kw):
super().__init__(*args, **kw)
self._read_fut = self._loop._proactor.recv(self._sock, 16)
self._read_fut.add_done_callback(self._pipe_closed)
def _pipe_closed(self, fut):
if fut.cancelled():
# the transport has been closed
return
assert fut.result() == b''
if self._closing:
assert self._read_fut is None
return
assert fut is self._read_fut, (fut, self._read_fut)
self._read_fut = None
if self._write_fut is not None:
self._force_close(BrokenPipeError())
else:
self.close()
class _ProactorDuplexPipeTransport(_ProactorReadPipeTransport,
_ProactorBaseWritePipeTransport,
transports.Transport):
"""Transport for duplex pipes."""
def can_write_eof(self):
return False
def write_eof(self):
raise NotImplementedError
class _ProactorSocketTransport(_ProactorReadPipeTransport,
_ProactorBaseWritePipeTransport,
transports.Transport):
"""Transport for connected sockets."""
def _set_extra(self, sock):
self._extra['socket'] = sock
try:
self._extra['sockname'] = sock.getsockname()
except (socket.error, AttributeError):
if self._loop.get_debug():
logger.warning("getsockname() failed on %r",
sock, exc_info=True)
if 'peername' not in self._extra:
try:
self._extra['peername'] = sock.getpeername()
except (socket.error, AttributeError):
if self._loop.get_debug():
logger.warning("getpeername() failed on %r",
sock, exc_info=True)
def can_write_eof(self):
return True
def write_eof(self):
if self._closing or self._eof_written:
return
self._eof_written = True
if self._write_fut is None:
self._sock.shutdown(socket.SHUT_WR)
class BaseProactorEventLoop(base_events.BaseEventLoop):
def __init__(self, proactor):
super().__init__()
logger.debug('Using proactor: %s', proactor.__class__.__name__)
self._proactor = proactor
self._selector = proactor # convenient alias
self._self_reading_future = None
self._accept_futures = {} # socket file descriptor => Future
proactor.set_loop(self)
self._make_self_pipe()
def _make_socket_transport(self, sock, protocol, waiter=None,
extra=None, server=None):
return _ProactorSocketTransport(self, sock, protocol, waiter,
extra, server)
def _make_ssl_transport(self, rawsock, protocol, sslcontext, waiter=None,
*, server_side=False, server_hostname=None,
extra=None, server=None):
if not sslproto._is_sslproto_available():
raise NotImplementedError("Proactor event loop requires Python 3.5"
" or newer (ssl.MemoryBIO) to support "
"SSL")
ssl_protocol = sslproto.SSLProtocol(self, protocol, sslcontext, waiter,
server_side, server_hostname)
_ProactorSocketTransport(self, rawsock, ssl_protocol,
extra=extra, server=server)
return ssl_protocol._app_transport
def _make_duplex_pipe_transport(self, sock, protocol, waiter=None,
extra=None):
return _ProactorDuplexPipeTransport(self,
sock, protocol, waiter, extra)
def _make_read_pipe_transport(self, sock, protocol, waiter=None,
extra=None):
return _ProactorReadPipeTransport(self, sock, protocol, waiter, extra)
def _make_write_pipe_transport(self, sock, protocol, waiter=None,
extra=None):
# We want connection_lost() to be called when other end closes
return _ProactorWritePipeTransport(self,
sock, protocol, waiter, extra)
def close(self):
if self.is_running():
raise RuntimeError("Cannot close a running event loop")
if self.is_closed():
return
# Call these methods before closing the event loop (before calling
# BaseEventLoop.close), because they can schedule callbacks with
# call_soon(), which is forbidden when the event loop is closed.
self._stop_accept_futures()
self._close_self_pipe()
self._proactor.close()
self._proactor = None
self._selector = None
# Close the event loop
super().close()
def sock_recv(self, sock, n):
return self._proactor.recv(sock, n)
def sock_sendall(self, sock, data):
return self._proactor.send(sock, data)
def sock_connect(self, sock, address):
try:
base_events._check_resolved_address(sock, address)
except ValueError as err:
fut = futures.Future(loop=self)
fut.set_exception(err)
return fut
else:
return self._proactor.connect(sock, address)
def sock_accept(self, sock):
return self._proactor.accept(sock)
def _socketpair(self):
raise NotImplementedError
def _close_self_pipe(self):
if self._self_reading_future is not None:
self._self_reading_future.cancel()
self._self_reading_future = None
self._ssock.close()
self._ssock = None
self._csock.close()
self._csock = None
self._internal_fds -= 1
def _make_self_pipe(self):
# A self-socket, really. :-)
self._ssock, self._csock = self._socketpair()
self._ssock.setblocking(False)
self._csock.setblocking(False)
self._internal_fds += 1
self.call_soon(self._loop_self_reading)
def _loop_self_reading(self, f=None):
try:
if f is not None:
f.result() # may raise
f = self._proactor.recv(self._ssock, 4096)
except:
self.close()
raise
else:
self._self_reading_future = f
f.add_done_callback(self._loop_self_reading)
def _write_to_self(self):
self._csock.send(b'\0')
def _start_serving(self, protocol_factory, sock,
sslcontext=None, server=None):
def loop(f=None):
try:
if f is not None:
conn, addr = f.result()
if self._debug:
logger.debug("%r got a new connection from %r: %r",
server, addr, conn)
protocol = protocol_factory()
if sslcontext is not None:
self._make_ssl_transport(
conn, protocol, sslcontext, server_side=True,
extra={'peername': addr}, server=server)
else:
self._make_socket_transport(
conn, protocol,
extra={'peername': addr}, server=server)
if self.is_closed():
return
f = self._proactor.accept(sock)
except OSError as exc:
if sock.fileno() != -1:
self.call_exception_handler({
'message': 'Accept failed on a socket',
'exception': exc,
'socket': sock,
})
sock.close()
elif self._debug:
logger.debug("Accept failed on socket %r",
sock, exc_info=True)
except futures.CancelledError:
sock.close()
else:
self._accept_futures[sock.fileno()] = f
f.add_done_callback(loop)
self.call_soon(loop)
def _process_events(self, event_list):
# Events are processed in the IocpProactor._poll() method
pass
def _stop_accept_futures(self):
for future in self._accept_futures.values():
future.cancel()
self._accept_futures.clear()
def _stop_serving(self, sock):
self._stop_accept_futures()
self._proactor._stop_serving(sock)
sock.close()