Committing Py3k version of changelist 64080 and 64257, along with updated tests

for smtpd, which required updating with the new semantics.

Doc/library/asynchat.rst

@@ -81,6 +81,12 @@ connection requests.
    :exc:`NotImplementedError` exception.
 
 
+.. method:: async_chat._collect_incoming_data(data)
+
+   Sample implementation of a data collection rutine to be used in conjunction
+   with :meth:`_get_data` in a user-specified :meth:`found_terminator`.
+
+
 .. method:: async_chat.discard_buffers()
 
    In emergencies this method will discard any data held in the input and/or
@@ -95,6 +101,12 @@ connection requests.
    should be available via an instance attribute.
 
 
+.. method:: async_chat._get_data()
+
+   Will return and clear the data received with the sample
+   :meth:`_collect_incoming_data` implementation.
+
+
 .. method:: async_chat.get_terminator()
 
    Returns the current terminator for the channel.

Doc/library/asyncore.rst

@@ -222,6 +222,21 @@ any that have been added to the map during asynchronous service) is closed.
       flushed).  Sockets are automatically closed when they are
       garbage-collected.
 
+.. class:: file_dispatcher()
+
+   A file_dispatcher takes a file descriptor or file object along with an
+   optional map argument and wraps it for use with the :cfunc:`poll` or
+   :cfunc:`loop` functions.  If provided a file object or anything with a
+   :cfunc:`fileno` method, that method will be called and passed to the
+   :class:`file_wrapper` constructor.  Availability: UNIX.
+
+.. class:: file_wrapper()
+
+   A file_wrapper takes an integer file descriptor and calls :func:`os.dup` to
+   duplicate the handle so that the original handle may be closed independently
+   of the file_wrapper.  This class implements sufficient methods to emulate a
+   socket for use by the :class:`file_dispatcher` class.  Availability: UNIX.
+
 
 .. _asyncore-example:
 

Lib/asynchat.py

@@ -45,12 +45,23 @@ command will be accumulated (using your own 'collect_incoming_data'
 method) up to the terminator, and then control will be returned to
 you - by calling your self.found_terminator() method.
 """
-
-import sys
 import socket
 import asyncore
 from collections import deque
 
+def buffer(obj, start=None, stop=None):
+    # if memoryview objects gain slicing semantics,
+    # this function will change for the better
+    # memoryview used for the TypeError
+    memoryview(obj)
+    if start == None:
+        start = 0
+    if stop == None:
+        stop = len(obj)
+    x = obj[start:stop]
+    ## print("buffer type is: %s"%(type(x),))
+    return x
+
 class async_chat (asyncore.dispatcher):
     """This is an abstract class.  You must derive from this class, and add
     the two methods collect_incoming_data() and found_terminator()"""
@@ -60,20 +71,47 @@ class async_chat (asyncore.dispatcher):
     ac_in_buffer_size       = 4096
     ac_out_buffer_size      = 4096
 
+    # we don't want to enable the use of encoding by default, because that is a
+    # sign of an application bug that we don't want to pass silently
+
+    use_encoding            = 0
+    encoding                = 'latin1'
+
     def __init__ (self, conn=None):
+        # for string terminator matching
         self.ac_in_buffer = b''
-        self.ac_out_buffer = b''
+
-        self.producer_fifo = fifo()
+        # we use a list here rather than cStringIO for a few reasons...
+        # del lst[:] is faster than sio.truncate(0)
+        # lst = [] is faster than sio.truncate(0)
+        # cStringIO will be gaining unicode support in py3k, which
+        # will negatively affect the performance of bytes compared to
+        # a ''.join() equivalent
+        self.incoming = []
+
+        # we toss the use of the "simple producer" and replace it with
+        # a pure deque, which the original fifo was a wrapping of
+        self.producer_fifo = deque()
         asyncore.dispatcher.__init__ (self, conn)
 
     def collect_incoming_data(self, data):
         raise NotImplementedError("must be implemented in subclass")
 
+    def _collect_incoming_data(self, data):
+        self.incoming.append(data)
+
+    def _get_data(self):
+        d = b''.join(self.incoming)
+        del self.incoming[:]
+        return d
+
     def found_terminator(self):
         raise NotImplementedError("must be implemented in subclass")
 
     def set_terminator (self, term):
         "Set the input delimiter.  Can be a fixed string of any length, an integer, or None"
+        if isinstance(term, str) and self.use_encoding:
+            term = bytes(term, self.encoding)
         self.terminator = term
 
     def get_terminator (self):
@@ -92,14 +130,14 @@ class async_chat (asyncore.dispatcher):
             self.handle_error()
             return
 
-        if isinstance(data, str):
+        if isinstance(data, str) and self.use_encoding:
-            data = data.encode('ascii')
+            data = bytes(str, self.encoding)
-        self.ac_in_buffer = self.ac_in_buffer + bytes(data)
+        self.ac_in_buffer = self.ac_in_buffer + data
 
         # Continue to search for self.terminator in self.ac_in_buffer,
         # while calling self.collect_incoming_data.  The while loop
         # is necessary because we might read several data+terminator
-        # combos with a single recv(1024).
+        # combos with a single recv(4096).
 
         while self.ac_in_buffer:
             lb = len(self.ac_in_buffer)
@@ -108,7 +146,7 @@ class async_chat (asyncore.dispatcher):
                 # no terminator, collect it all
                 self.collect_incoming_data (self.ac_in_buffer)
                 self.ac_in_buffer = b''
-            elif isinstance(terminator, int) or isinstance(terminator, int):
+            elif isinstance(terminator, int):
                 # numeric terminator
                 n = terminator
                 if lb < n:
@@ -129,8 +167,6 @@ class async_chat (asyncore.dispatcher):
                 # 3) end of buffer does not match any prefix:
                 #    collect data
                 terminator_len = len(terminator)
-                if isinstance(terminator, str):
-                    terminator = terminator.encode('ascii')
                 index = self.ac_in_buffer.find(terminator)
                 if index != -1:
                     # we found the terminator
@@ -161,85 +197,81 @@ class async_chat (asyncore.dispatcher):
         self.close()
 
     def push (self, data):
-        self.producer_fifo.push (simple_producer (data))
+        sabs = self.ac_out_buffer_size
+        if len(data) > sabs:
+            for i in range(0, len(data), sabs):
+                self.producer_fifo.append(data[i:i+sabs])
+        else:
+            self.producer_fifo.append(data)
         self.initiate_send()
 
     def push_with_producer (self, producer):
-        self.producer_fifo.push (producer)
+        self.producer_fifo.append(producer)
         self.initiate_send()
 
     def readable (self):
         "predicate for inclusion in the readable for select()"
-        return (len(self.ac_in_buffer) <= self.ac_in_buffer_size)
+        # cannot use the old predicate, it violates the claim of the
+        # set_terminator method.
+
+        # return (len(self.ac_in_buffer) <= self.ac_in_buffer_size)
+        return 1
 
     def writable (self):
         "predicate for inclusion in the writable for select()"
-        # return len(self.ac_out_buffer) or len(self.producer_fifo) or (not self.connected)
+        return self.producer_fifo or (not self.connected)
-        # this is about twice as fast, though not as clear.
-        return not (
-                (self.ac_out_buffer == b'') and
-                self.producer_fifo.is_empty() and
-                self.connected
-                )
 
     def close_when_done (self):
         "automatically close this channel once the outgoing queue is empty"
-        self.producer_fifo.push (None)
+        self.producer_fifo.append(None)
-
-    # refill the outgoing buffer by calling the more() method
-    # of the first producer in the queue
-    def refill_buffer (self):
-        while 1:
-            if len(self.producer_fifo):
-                p = self.producer_fifo.first()
-                # a 'None' in the producer fifo is a sentinel,
-                # telling us to close the channel.
-                if p is None:
-                    if not self.ac_out_buffer:
-                        self.producer_fifo.pop()
-                        self.close()
-                    return
-                elif isinstance(p, str) or isinstance(p, bytes):
-                    if isinstance(p, str):
-                        p = p.encode('ascii')
-                    self.producer_fifo.pop()
-                    self.ac_out_buffer = self.ac_out_buffer + p
-                    return
-                data = p.more()
-                if data:
-                    if isinstance(data, str):
-                        data = data.encode('ascii')
-                    self.ac_out_buffer = self.ac_out_buffer + bytes(data)
-                    return
-                else:
-                    self.producer_fifo.pop()
-            else:
-                return
 
     def initiate_send(self):
+        while self.producer_fifo and self.connected:
+            first = self.producer_fifo[0]
+            # handle empty string/buffer or None entry
+            if not first:
+                del self.producer_fifo[0]
+                if first is None:
+                    ## print("first is None")
+                    self.handle_close()
+                    return
+                ## print("first is not None")
+
+            # handle classic producer behavior
             obs = self.ac_out_buffer_size
-        # try to refill the buffer
-        if (len (self.ac_out_buffer) < obs):
-            self.refill_buffer()
-
-        if self.ac_out_buffer and self.connected:
-            # try to send the buffer
             try:
-                num_sent = self.send (self.ac_out_buffer[:obs])
+                data = buffer(first, 0, obs)
-                if num_sent:
+            except TypeError:
-                    self.ac_out_buffer = self.ac_out_buffer[num_sent:]
+                data = first.more()
+                if data:
+                    self.producer_fifo.appendleft(data)
+                else:
+                    del self.producer_fifo[0]
+                continue
 
-            except socket.error as why:
+            if isinstance(data, str) and self.use_encoding:
+                data = bytes(data, self.encoding)
+
+            # send the data
+            try:
+                num_sent = self.send(data)
+            except socket.error:
                 self.handle_error()
                 return
 
+            if num_sent:
+                if num_sent < len(data) or obs < len(first):
+                    self.producer_fifo[0] = first[num_sent:]
+                else:
+                    del self.producer_fifo[0]
+            # we tried to send some actual data
+            return
+
     def discard_buffers (self):
         # Emergencies only!
         self.ac_in_buffer = b''
-        self.ac_out_buffer = b''
+        del self.incoming[:]
-        while self.producer_fifo:
+        self.producer_fifo.clear()
-            self.producer_fifo.pop()
-
 
 class simple_producer:
 

Lib/asyncore.py

@@ -50,23 +50,28 @@ import select
 import socket
 import sys
 import time
-
 import os
 from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, \
-     ENOTCONN, ESHUTDOWN, EINTR, EISCONN, errorcode
+     ENOTCONN, ESHUTDOWN, EINTR, EISCONN, EBADF, ECONNABORTED, errorcode
 
 try:
     socket_map
 except NameError:
     socket_map = {}
 
+def _strerror(err):
+    res = os.strerror(err)
+    if res == 'Unknown error':
+        res = errorcode[err]
+    return res
+
 class ExitNow(Exception):
     pass
 
 def read(obj):
     try:
         obj.handle_read_event()
-    except ExitNow:
+    except (ExitNow, KeyboardInterrupt, SystemExit):
         raise
     except:
         obj.handle_error()
@@ -74,7 +79,7 @@ def read(obj):
 def write(obj):
     try:
         obj.handle_write_event()
-    except ExitNow:
+    except (ExitNow, KeyboardInterrupt, SystemExit):
         raise
     except:
         obj.handle_error()
@@ -82,7 +87,7 @@ def write(obj):
 def _exception(obj):
     try:
         obj.handle_expt_event()
-    except ExitNow:
+    except (ExitNow, KeyboardInterrupt, SystemExit):
         raise
     except:
         obj.handle_error()
@@ -95,7 +100,7 @@ def readwrite(obj, flags):
             obj.handle_write_event()
         if flags & (select.POLLERR | select.POLLHUP | select.POLLNVAL):
             obj.handle_expt_event()
-    except ExitNow:
+    except (ExitNow, KeyboardInterrupt, SystemExit):
         raise
     except:
         obj.handle_error()
@@ -105,7 +110,7 @@ def poll(timeout=0.0, map=None):
         map = socket_map
     if map:
         r = []; w = []; e = []
-        for fd, obj in map.items():
+        for fd, obj in list(map.items()):
             is_r = obj.readable()
             is_w = obj.writable()
             if is_r:
@@ -116,11 +121,12 @@ def poll(timeout=0.0, map=None):
                 e.append(fd)
         if [] == r == w == e:
             time.sleep(timeout)
-        else:
+            return
+
         try:
             r, w, e = select.select(r, w, e, timeout)
         except select.error as err:
-                if err.args[0] != EINTR:
+            if err[0] != EINTR:
                 raise
             else:
                 return
@@ -152,7 +158,7 @@ def poll2(timeout=0.0, map=None):
         timeout = int(timeout*1000)
     pollster = select.poll()
     if map:
-        for fd, obj in map.items():
+        for fd, obj in list(map.items()):
             flags = 0
             if obj.readable():
                 flags |= select.POLLIN | select.POLLPRI
@@ -166,7 +172,7 @@ def poll2(timeout=0.0, map=None):
         try:
             r = pollster.poll(timeout)
         except select.error as err:
-            if err.args[0] != EINTR:
+            if err[0] != EINTR:
                 raise
             r = []
         for fd, flags in r:
@@ -209,18 +215,29 @@ class dispatcher:
         else:
             self._map = map
 
+        self._fileno = None
+
         if sock:
+            # Set to nonblocking just to make sure for cases where we
+            # get a socket from a blocking source.
+            sock.setblocking(0)
             self.set_socket(sock, map)
-            # I think it should inherit this anyway
-            self.socket.setblocking(0)
             self.connected = True
-            # XXX Does the constructor require that the socket passed
+            # The constructor no longer requires that the socket
-            # be connected?
+            # passed be connected.
             try:
                 self.addr = sock.getpeername()
-            except socket.error:
+            except socket.error as err:
-                # The addr isn't crucial
+                if err[0] == ENOTCONN:
-                pass
+                    # To handle the case where we got an unconnected
+                    # socket.
+                    self.connected = False
+                else:
+                    # The socket is broken in some unknown way, alert
+                    # the user and remove it from the map (to prevent
+                    # polling of broken sockets).
+                    self.del_channel(map)
+                    raise
         else:
             self.socket = None
 
@@ -254,10 +271,9 @@ class dispatcher:
 
     def create_socket(self, family, type):
         self.family_and_type = family, type
-        self.socket = socket.socket(family, type)
+        sock = socket.socket(family, type)
-        self.socket.setblocking(0)
+        sock.setblocking(0)
-        self._fileno = self.socket.fileno()
+        self.set_socket(sock)
-        self.add_channel()
 
     def set_socket(self, sock, map=None):
         self.socket = sock
@@ -295,7 +311,7 @@ class dispatcher:
     def listen(self, num):
         self.accepting = True
         if os.name == 'nt' and num > 5:
-            num = 1
+            num = 5
         return self.socket.listen(num)
 
     def bind(self, addr):
@@ -310,8 +326,7 @@ class dispatcher:
             return
         if err in (0, EISCONN):
             self.addr = address
-            self.connected = True
+            self.handle_connect_event()
-            self.handle_connect()
         else:
             raise socket.error(err, errorcode[err])
 
@@ -321,7 +336,7 @@ class dispatcher:
             conn, addr = self.socket.accept()
             return conn, addr
         except socket.error as why:
-            if why.args[0] == EWOULDBLOCK:
+            if why[0] == EWOULDBLOCK:
                 pass
             else:
                 raise
@@ -331,11 +346,13 @@ class dispatcher:
             result = self.socket.send(data)
             return result
         except socket.error as why:
-            if why.args[0] == EWOULDBLOCK:
+            if why[0] == EWOULDBLOCK:
+                return 0
+            elif why[0] in (ECONNRESET, ENOTCONN, ESHUTDOWN, ECONNABORTED):
+                self.handle_close()
                 return 0
             else:
                 raise
-            return 0
 
     def recv(self, buffer_size):
         try:
@@ -349,15 +366,21 @@ class dispatcher:
                 return data
         except socket.error as why:
             # winsock sometimes throws ENOTCONN
-            if why.args[0] in [ECONNRESET, ENOTCONN, ESHUTDOWN]:
+            if why[0] in [ECONNRESET, ENOTCONN, ESHUTDOWN, ECONNABORTED]:
                 self.handle_close()
                 return b''
             else:
                 raise
 
     def close(self):
+        self.connected = False
+        self.accepting = False
         self.del_channel()
+        try:
             self.socket.close()
+        except socket.error as why:
+            if why[0] not in (ENOTCONN, EBADF):
+                raise
 
     # cheap inheritance, used to pass all other attribute
     # references to the underlying socket object.
@@ -377,26 +400,52 @@ class dispatcher:
 
     def handle_read_event(self):
         if self.accepting:
-            # for an accepting socket, getting a read implies
+            # accepting sockets are never connected, they "spawn" new
-            # that we are connected
+            # sockets that are connected
-            if not self.connected:
-                self.connected = True
             self.handle_accept()
         elif not self.connected:
-            self.handle_connect()
+            self.handle_connect_event()
-            self.connected = True
             self.handle_read()
         else:
             self.handle_read()
 
-    def handle_write_event(self):
+    def handle_connect_event(self):
-        # getting a write implies that we are connected
-        if not self.connected:
-            self.handle_connect()
         self.connected = True
+        self.handle_connect()
+
+    def handle_write_event(self):
+        if self.accepting:
+            # Accepting sockets shouldn't get a write event.
+            # We will pretend it didn't happen.
+            return
+
+        if not self.connected:
+            #check for errors
+            err = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
+            if err != 0:
+                raise socket.error(err, _strerror(err))
+
+            self.handle_connect_event()
         self.handle_write()
 
     def handle_expt_event(self):
+        # if the handle_expt is the same default worthless method,
+        # we'll not even bother calling it, we'll instead generate
+        # a useful error
+        x = True
+        try:
+            y1 = self.handle_expt.__func__
+            y2 = dispatcher.handle_expt
+            x = y1 is y2
+        except AttributeError:
+            pass
+
+        if x:
+            err = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
+            msg = _strerror(err)
+
+            raise socket.error(err, msg)
+        else:
             self.handle_expt()
 
     def handle_error(self):
@@ -461,7 +510,6 @@ class dispatcher_with_send(dispatcher):
         return (not self.connected) or len(self.out_buffer)
 
     def send(self, data):
-        assert isinstance(data, bytes)
         if self.debug:
             self.log_info('sending %s' % repr(data))
         self.out_buffer = self.out_buffer + data
@@ -474,7 +522,8 @@ class dispatcher_with_send(dispatcher):
 def compact_traceback():
     t, v, tb = sys.exc_info()
     tbinfo = []
-    assert tb # Must have a traceback
+    if not tb: # Must have a traceback
+        raise AssertionError("traceback does not exist")
     while tb:
         tbinfo.append((
             tb.tb_frame.f_code.co_filename,
@@ -490,11 +539,22 @@ def compact_traceback():
     info = ' '.join(['[%s|%s|%s]' % x for x in tbinfo])
     return (file, function, line), t, v, info
 
-def close_all(map=None):
+def close_all(map=None, ignore_all=False):
     if map is None:
         map = socket_map
-    for x in map.values():
+    for x in list(map.values()):
-        x.socket.close()
+        try:
+            x.close()
+        except OSError as x:
+            if x[0] == EBADF:
+                pass
+            elif not ignore_all:
+                raise
+        except (ExitNow, KeyboardInterrupt, SystemExit):
+            raise
+        except:
+            if not ignore_all:
+                raise
     map.clear()
 
 # Asynchronous File I/O:
@@ -514,11 +574,12 @@ if os.name == 'posix':
     import fcntl
 
     class file_wrapper:
-        # here we override just enough to make a file
+        # Here we override just enough to make a file
         # look like a socket for the purposes of asyncore.
+        # The passed fd is automatically os.dup()'d
 
         def __init__(self, fd):
-            self.fd = fd
+            self.fd = os.dup(fd)
 
         def recv(self, *args):
             return os.read(self.fd, *args)
@@ -540,6 +601,10 @@ if os.name == 'posix':
         def __init__(self, fd, map=None):
             dispatcher.__init__(self, None, map)
             self.connected = True
+            try:
+                fd = fd.fileno()
+            except AttributeError:
+                pass
             self.set_file(fd)
             # set it to non-blocking mode
             flags = fcntl.fcntl(fd, fcntl.F_GETFL, 0)

Lib/smtpd.py

@@ -124,11 +124,11 @@ class SMTPChannel(asynchat.async_chat):
         self.__peer = conn.getpeername()
         print('Peer:', repr(self.__peer), file=DEBUGSTREAM)
         self.push('220 %s %s' % (self.__fqdn, __version__))
-        self.set_terminator('\r\n')
+        self.set_terminator(b'\r\n')
 
     # Overrides base class for convenience
     def push(self, msg):
-        asynchat.async_chat.push(self, msg + '\r\n')
+        asynchat.async_chat.push(self, bytes(msg + '\r\n', 'ascii'))
 
     # Implementation of base class abstract method
     def collect_incoming_data(self, data):
@@ -177,7 +177,7 @@ class SMTPChannel(asynchat.async_chat):
             self.__rcpttos = []
             self.__mailfrom = None
             self.__state = self.COMMAND
-            self.set_terminator('\r\n')
+            self.set_terminator(b'\r\n')
             if not status:
                 self.push('250 Ok')
             else:
@@ -264,7 +264,7 @@ class SMTPChannel(asynchat.async_chat):
             self.push('501 Syntax: DATA')
             return
         self.__state = self.DATA
-        self.set_terminator('\r\n.\r\n')
+        self.set_terminator(b'\r\n.\r\n')
         self.push('354 End data with <CR><LF>.<CR><LF>')
 
 

Lib/test/test_asynchat.py

@@ -105,8 +105,8 @@ class TestAsynchat(unittest.TestCase):
         time.sleep(0.01) # Give server time to start accepting.
         c = echo_client(term, s.port)
         c.push(b"hello ")
-        c.push(bytes("world%s" % term, "ascii"))
+        c.push(b"world" + term)
-        c.push(bytes("I'm not dead yet!%s" % term, "ascii"))
+        c.push(b"I'm not dead yet!" + term)
         c.push(SERVER_QUIT)
         asyncore.loop(use_poll=self.usepoll, count=300, timeout=.01)
         s.join()
@@ -120,17 +120,17 @@ class TestAsynchat(unittest.TestCase):
     def test_line_terminator1(self):
         # test one-character terminator
         for l in (1,2,3):
-            self.line_terminator_check('\n', l)
+            self.line_terminator_check(b'\n', l)
 
     def test_line_terminator2(self):
         # test two-character terminator
         for l in (1,2,3):
-            self.line_terminator_check('\r\n', l)
+            self.line_terminator_check(b'\r\n', l)
 
     def test_line_terminator3(self):
         # test three-character terminator
         for l in (1,2,3):
-            self.line_terminator_check('qqq', l)
+            self.line_terminator_check(b'qqq', l)
 
     def numeric_terminator_check(self, termlen):
         # Try reading a fixed number of bytes
@@ -190,7 +190,7 @@ class TestAsynchat(unittest.TestCase):
         # checks that empty lines are handled correctly
         s, event = start_echo_server()
         c = echo_client(b'\n', s.port)
-        c.push("hello world\n\nI'm not dead yet!\n")
+        c.push(b"hello world\n\nI'm not dead yet!\n")
         c.push(SERVER_QUIT)
         asyncore.loop(use_poll=self.usepoll, count=300, timeout=.01)
         s.join()
@@ -201,7 +201,7 @@ class TestAsynchat(unittest.TestCase):
     def test_close_when_done(self):
         s, event = start_echo_server()
         c = echo_client(b'\n', s.port)
-        c.push("hello world\nI'm not dead yet!\n")
+        c.push(b"hello world\nI'm not dead yet!\n")
         c.push(SERVER_QUIT)
         c.close_when_done()
         asyncore.loop(use_poll=self.usepoll, count=300, timeout=.01)

Lib/test/test_asyncore.py

@@ -28,6 +28,9 @@ class dummychannel:
     def __init__(self):
         self.socket = dummysocket()
 
+    def close(self):
+        self.socket.close()
+
 class exitingdummy:
     def __init__(self):
         pass
@@ -382,8 +385,8 @@ if hasattr(asyncore, 'file_wrapper'):
             fd = os.open(TESTFN, os.O_RDONLY)
             w = asyncore.file_wrapper(fd)
 
-            self.assertEqual(w.fd, fd)
+            self.assertNotEqual(w.fd, fd)
-            self.assertEqual(w.fileno(), fd)
+            self.assertNotEqual(w.fileno(), fd)
             self.assertEqual(w.recv(13), b"It's not dead")
             self.assertEqual(w.read(6), b", it's")
             w.close()

Lib/test/test_smtplib.py

@@ -14,6 +14,14 @@ from test import support
 
 HOST = support.HOST
 
+if sys.platform == 'darwin':
+    # select.poll returns a select.POLLHUP at the end of the tests
+    # on darwin, so just ignore it
+    def handle_expt(self):
+        pass
+    smtpd.SMTPChannel.handle_expt = handle_expt
+
+
 def server(evt, buf, serv):
     serv.listen(5)
     evt.set()