bpo-37027: Return a proxy socket object from transp.get_extra_info('socket') (GH-13530)

Return a safe to use proxy socket object from `transport.get_extra_info('socket')`




https://bugs.python.org/issue37027

Lib/asyncio/base_events.py

@@ -45,6 +45,7 @@ from . import sslproto
 from . import staggered
 from . import tasks
 from . import transports
+from . import trsock
 from .log import logger
 
 
@@ -319,8 +320,8 @@ class Server(events.AbstractServer):
     @property
     def sockets(self):
         if self._sockets is None:
-            return []
+            return ()
-        return list(self._sockets)
+        return tuple(trsock.TransportSocket(s) for s in self._sockets)
 
     def close(self):
         sockets = self._sockets

Lib/asyncio/proactor_events.py

@@ -19,6 +19,7 @@ from . import exceptions
 from . import protocols
 from . import sslproto
 from . import transports
+from . import trsock
 from .log import logger
 
 
@@ -454,7 +455,7 @@ class _ProactorSocketTransport(_ProactorReadPipeTransport,
         base_events._set_nodelay(sock)
 
     def _set_extra(self, sock):
-        self._extra['socket'] = sock
+        self._extra['socket'] = trsock.TransportSocket(sock)
 
         try:
             self._extra['sockname'] = sock.getsockname()
@@ -679,7 +680,7 @@ class BaseProactorEventLoop(base_events.BaseEventLoop):
                     self.call_exception_handler({
                         'message': 'Accept failed on a socket',
                         'exception': exc,
-                        'socket': sock,
+                        'socket': trsock.TransportSocket(sock),
                     })
                     sock.close()
                 elif self._debug:

Lib/asyncio/selector_events.py

@@ -25,6 +25,7 @@ from . import futures
 from . import protocols
 from . import sslproto
 from . import transports
+from . import trsock
 from .log import logger
 
 
@@ -171,7 +172,7 @@ class BaseSelectorEventLoop(base_events.BaseEventLoop):
                     self.call_exception_handler({
                         'message': 'socket.accept() out of system resource',
                         'exception': exc,
-                        'socket': sock,
+                        'socket': trsock.TransportSocket(sock),
                     })
                     self._remove_reader(sock.fileno())
                     self.call_later(constants.ACCEPT_RETRY_DELAY,
@@ -603,7 +604,7 @@ class _SelectorTransport(transports._FlowControlMixin,
 
     def __init__(self, loop, sock, protocol, extra=None, server=None):
         super().__init__(extra, loop)
-        self._extra['socket'] = sock
+        self._extra['socket'] = trsock.TransportSocket(sock)
         try:
             self._extra['sockname'] = sock.getsockname()
         except OSError:

Lib/asyncio/trsock.py

@@ -0,0 +1,206 @@
+import socket
+import warnings
+
+
+class TransportSocket:
+
+    """A socket-like wrapper for exposing real transport sockets.
+
+    These objects can be safely returned by APIs like
+    `transport.get_extra_info('socket')`.  All potentially disruptive
+    operations (like "socket.close()") are banned.
+    """
+
+    __slots__ = ('_sock',)
+
+    def __init__(self, sock: socket.socket):
+        self._sock = sock
+
+    def _na(self, what):
+        warnings.warn(
+            f"Using {what} on sockets returned from get_extra_info('socket') "
+            f"will be prohibited in asyncio 3.9. Please report your use case "
+            f"to bugs.python.org.",
+            DeprecationWarning, source=self)
+
+    @property
+    def family(self):
+        return self._sock.family
+
+    @property
+    def type(self):
+        return self._sock.type
+
+    @property
+    def proto(self):
+        return self._sock.proto
+
+    def __repr__(self):
+        s = (
+            f"<asyncio.TransportSocket fd={self.fileno()}, "
+            f"family={self.family!s}, type={self.type!s}, "
+            f"proto={self.proto}"
+        )
+
+        if self.fileno() != -1:
+            try:
+                laddr = self.getsockname()
+                if laddr:
+                    s = f"{s}, laddr={laddr}"
+            except socket.error:
+                pass
+            try:
+                raddr = self.getpeername()
+                if raddr:
+                    s = f"{s}, raddr={raddr}"
+            except socket.error:
+                pass
+
+        return f"{s}>"
+
+    def __getstate__(self):
+        raise TypeError("Cannot serialize asyncio.TransportSocket object")
+
+    def fileno(self):
+        return self._sock.fileno()
+
+    def dup(self):
+        return self._sock.dup()
+
+    def get_inheritable(self):
+        return self._sock.get_inheritable()
+
+    def shutdown(self, how):
+        # asyncio doesn't currently provide a high-level transport API
+        # to shutdown the connection.
+        self._sock.shutdown(how)
+
+    def getsockopt(self, *args, **kwargs):
+        return self._sock.getsockopt(*args, **kwargs)
+
+    def setsockopt(self, *args, **kwargs):
+        self._sock.setsockopt(*args, **kwargs)
+
+    def getpeername(self):
+        return self._sock.getpeername()
+
+    def getsockname(self):
+        return self._sock.getsockname()
+
+    def getsockbyname(self):
+        return self._sock.getsockbyname()
+
+    def accept(self):
+        self._na('accept() method')
+        return self._sock.accept()
+
+    def connect(self, *args, **kwargs):
+        self._na('connect() method')
+        return self._sock.connect(*args, **kwargs)
+
+    def connect_ex(self, *args, **kwargs):
+        self._na('connect_ex() method')
+        return self._sock.connect_ex(*args, **kwargs)
+
+    def bind(self, *args, **kwargs):
+        self._na('bind() method')
+        return self._sock.bind(*args, **kwargs)
+
+    def ioctl(self, *args, **kwargs):
+        self._na('ioctl() method')
+        return self._sock.ioctl(*args, **kwargs)
+
+    def listen(self, *args, **kwargs):
+        self._na('listen() method')
+        return self._sock.listen(*args, **kwargs)
+
+    def makefile(self):
+        self._na('makefile() method')
+        return self._sock.makefile()
+
+    def sendfile(self, *args, **kwargs):
+        self._na('sendfile() method')
+        return self._sock.sendfile(*args, **kwargs)
+
+    def close(self):
+        self._na('close() method')
+        return self._sock.close()
+
+    def detach(self):
+        self._na('detach() method')
+        return self._sock.detach()
+
+    def sendmsg_afalg(self, *args, **kwargs):
+        self._na('sendmsg_afalg() method')
+        return self._sock.sendmsg_afalg(*args, **kwargs)
+
+    def sendmsg(self, *args, **kwargs):
+        self._na('sendmsg() method')
+        return self._sock.sendmsg(*args, **kwargs)
+
+    def sendto(self, *args, **kwargs):
+        self._na('sendto() method')
+        return self._sock.sendto(*args, **kwargs)
+
+    def send(self, *args, **kwargs):
+        self._na('send() method')
+        return self._sock.send(*args, **kwargs)
+
+    def sendall(self, *args, **kwargs):
+        self._na('sendall() method')
+        return self._sock.sendall(*args, **kwargs)
+
+    def set_inheritable(self, *args, **kwargs):
+        self._na('set_inheritable() method')
+        return self._sock.set_inheritable(*args, **kwargs)
+
+    def share(self, process_id):
+        self._na('share() method')
+        return self._sock.share(process_id)
+
+    def recv_into(self, *args, **kwargs):
+        self._na('recv_into() method')
+        return self._sock.recv_into(*args, **kwargs)
+
+    def recvfrom_into(self, *args, **kwargs):
+        self._na('recvfrom_into() method')
+        return self._sock.recvfrom_into(*args, **kwargs)
+
+    def recvmsg_into(self, *args, **kwargs):
+        self._na('recvmsg_into() method')
+        return self._sock.recvmsg_into(*args, **kwargs)
+
+    def recvmsg(self, *args, **kwargs):
+        self._na('recvmsg() method')
+        return self._sock.recvmsg(*args, **kwargs)
+
+    def recvfrom(self, *args, **kwargs):
+        self._na('recvfrom() method')
+        return self._sock.recvfrom(*args, **kwargs)
+
+    def recv(self, *args, **kwargs):
+        self._na('recv() method')
+        return self._sock.recv(*args, **kwargs)
+
+    def settimeout(self, value):
+        if value == 0:
+            return
+        raise ValueError(
+            'settimeout(): only 0 timeout is allowed on transport sockets')
+
+    def gettimeout(self):
+        return 0
+
+    def setblocking(self, flag):
+        if not flag:
+            return
+        raise ValueError(
+            'setblocking(): transport sockets cannot be blocking')
+
+    def __enter__(self):
+        self._na('context manager protocol')
+        return self._sock.__enter__()
+
+    def __exit__(self, *err):
+        self._na('context manager protocol')
+        return self._sock.__exit__(*err)

Lib/test/test_asyncio/test_events.py

@@ -1118,7 +1118,7 @@ class EventLoopTestsMixin:
         f = self.loop.create_server(TestMyProto, sock=sock_ob)
         server = self.loop.run_until_complete(f)
         sock = server.sockets[0]
-        self.assertIs(sock, sock_ob)
+        self.assertEqual(sock.fileno(), sock_ob.fileno())
 
         host, port = sock.getsockname()
         self.assertEqual(host, '0.0.0.0')

Lib/test/test_asyncio/test_server.py

@@ -58,7 +58,7 @@ class BaseStartServer(func_tests.FunctionalTestCaseMixin):
             with self.tcp_client(lambda sock: client(sock, addr)):
                 self.loop.run_until_complete(main_task)
 
-        self.assertEqual(srv.sockets, [])
+        self.assertEqual(srv.sockets, ())
 
         self.assertIsNone(srv._sockets)
         self.assertIsNone(srv._waiters)
@@ -111,7 +111,7 @@ class SelectorStartServerTests(BaseStartServer, unittest.TestCase):
                 with self.unix_client(lambda sock: client(sock, addr)):
                     self.loop.run_until_complete(main_task)
 
-            self.assertEqual(srv.sockets, [])
+            self.assertEqual(srv.sockets, ())
 
             self.assertIsNone(srv._sockets)
             self.assertIsNone(srv._waiters)

Misc/NEWS.d/next/Library/2019-05-23-18-46-56.bpo-37027.iH4eut.rst

@@ -0,0 +1,2 @@
+Return safe to use proxy socket object from
+transport.get_extra_info('socket')