Bring medusa libraries up to date with current medusa stuff. This should...

Bring medusa libraries up to date with current medusa stuff. This should improve FTP Server on win95 problems, bogus DNS IP address problems, potential memory problems, and more. Also included in a little patch of my own to asyncore.py to fail on shutodown sockets in a slightly more friendly way.

ZServer/medusa/asynchat.py

 # -*- Mode: Python; tab-width: 4 -*-
-#	$Id: asynchat.py,v 1.7 1999/04/09 00:37:33 amos Exp $
+#	$Id: asynchat.py,v 1.8 1999/05/26 02:08:29 amos Exp $
 #	Author: Sam Rushing <rushing@nightmare.com>
 
 # ======================================================================
@@ -99,7 +99,6 @@ class async_chat (asyncore.dispatcher):
 			elif type(terminator) == type(0):
 				# numeric terminator
 				n = terminator
-				lb = lb
 				if lb < n:
 					self.collect_incoming_data (self.ac_in_buffer)
 					self.ac_in_buffer = ''
@@ -159,7 +158,13 @@ class async_chat (asyncore.dispatcher):
 
 	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 len(self.ac_out_buffer) or len(self.producer_fifo) or (not self.connected)
+		# this is about twice as fast, though not as clear.
+		return not (
+			(self.ac_out_buffer is '') and
+			self.producer_fifo.is_empty() and
+			self.connected
+			)
 
 	def close_when_done (self):
 		"automatically close this channel once the outgoing queue is empty"
@@ -242,6 +247,9 @@ class fifo:
 	def __len__ (self):
 		return len(self.list)
 
+	def is_empty (self):
+		return self.list == []
+
 	def first (self):
 		return self.list[0]
 

ZServer/medusa/asyncore.py

 # -*- Mode: Python; tab-width: 4 -*-
-# 	$Id: asyncore.py,v 1.2 1999/04/09 00:37:33 amos Exp $
+# 	$Id: asyncore.py,v 1.3 1999/05/26 02:08:30 amos Exp $
 #	Author: Sam Rushing <rushing@nightmare.com>
 
 # ======================================================================
@@ -37,17 +37,20 @@ if os.name == 'nt':
 	EALREADY	= 10037
 	ECONNRESET  = 10054
 	ENOTCONN	= 10057
+	ESHUTDOWN   = 10058
 else:
-	from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, ENOTCONN
+	from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, ENOTCONN, ESHUTDOWN
 
 socket_map = {}
 
 def poll (timeout=0.0):
 	if socket_map:
-		sockets = socket_map.keys()
-		r = filter (lambda x: x.readable(), sockets)
-		w = filter (lambda x: x.writable(), sockets)
-		e = []
+		r = []; w = []; e = []
+		for s in socket_map.keys():
+			if s.readable():
+				r.append (s)
+			if s.writable():
+				w.append (s)
 
 		(r,w,e) = select.select (r,w,e, timeout)
 
@@ -140,12 +143,14 @@ class dispatcher:
 			return '<__repr__ (self) failed for object at %x (addr=%s)>' % (id(self),ar)
 
 	def add_channel (self):
-		self.log ('adding channel %s' % self)
+		if __debug__:
+			self.log ('adding channel %s' % self)
 		socket_map [self] = 1
 
 	def del_channel (self):
 		if socket_map.has_key (self):
-			self.log ('closing channel %d:%s' % (self.fileno(), self))
+			if __debug__:
+				self.log ('closing channel %d:%s' % (self.fileno(), self))
 			del socket_map [self]
 
 	def create_socket (self, family, type):
@@ -155,7 +160,8 @@ class dispatcher:
 		self.add_channel()
 
 	def set_socket (self, socket):
-		self.socket = socket
+		# This is done so we can be called safely from __init__
+		self.__dict__['socket'] = socket
 		self.add_channel()
 
 	def set_reuse_addr (self):
@@ -245,7 +251,7 @@ class dispatcher:
 				return data
 		except socket.error, why:
 			# winsock sometimes throws ENOTCONN
-			if why[0] in [ECONNRESET, ENOTCONN]:
+			if why[0] in [ECONNRESET, ENOTCONN, ESHUTDOWN]:
 				self.handle_close()
 				return ''
 			else:
@@ -257,11 +263,9 @@ class dispatcher:
 
 	# cheap inheritance, used to pass all other attribute
 	# references to the underlying socket object.
+	# NOTE: this may be removed soon for performance reasons.
 	def __getattr__ (self, attr):
-		if attr != 'socket':
-			return getattr (self.socket, attr)
-		else:
-			raise AttributeError, attr
+		return getattr (self.socket, attr)
 
 	def log (self, message):
 		print 'log:', message
@@ -310,22 +314,28 @@ class dispatcher:
 		self.close()
 
 	def handle_expt (self):
-		self.log ('unhandled exception')
+		if __debug__:
+			self.log ('unhandled exception')
 
 	def handle_read (self):
-		self.log ('unhandled read event')
+		if __debug__:
+			self.log ('unhandled read event')
 
 	def handle_write (self):
-		self.log ('unhandled write event')
+		if __debug__:
+			self.log ('unhandled write event')
 
 	def handle_connect (self):
-		self.log ('unhandled connect event')
+		if __debug__:
+			self.log ('unhandled connect event')
 
 	def handle_accept (self):
-		self.log ('unhandled accept event')
+		if __debug__:
+			self.log ('unhandled accept event')
 
 	def handle_close (self):
-		self.log ('unhandled close event')
+		if __debug__:
+			self.log ('unhandled close event')
 		self.close()
 
 # ---------------------------------------------------------------------------

ZServer/medusa/ftp_server.py

@@ -8,7 +8,7 @@
 # If you are interested in using this software in a commercial context,
 # or in purchasing support, please contact the author.
 
-RCS_ID =  '$Id: ftp_server.py,v 1.4 1999/04/29 23:36:09 amos Exp $'
+RCS_ID =  '$Id: ftp_server.py,v 1.5 1999/05/26 02:08:30 amos Exp $'
 
 # An extensible, configurable, asynchronous FTP server.
 # 
@@ -54,9 +54,6 @@ import time
 
 VERSION = string.split(RCS_ID)[2]
 
-IP_ADDRESS = socket.gethostbyname (socket.gethostname())
-HOSTNAME = socket.gethostbyaddr (IP_ADDRESS)[0]
-
 from counter import counter
 import producers
 import status_handler
@@ -286,7 +283,7 @@ class ftp_channel (asynchat.async_chat):
 		if pa:
 			if pa.ready:
 				# a connection has already been made.
-				conn, addr = self.passive_acceptor.ready
+				conn, addr = pa.ready
 				cdc = recv_channel (self, addr, fd)
 				cdc.set_socket (conn)
 				cdc.connected = 1
@@ -698,14 +695,19 @@ class ftp_server (asyncore.dispatcher):
 	def __init__ (
 		self,
 		authorizer,
-		hostname	=HOSTNAME,
+		hostname	=None,
 		port		=21,
 		resolver	=None,
 		logger_object=logger.file_logger (sys.stdout)
 		):
 		self.port = port
 		self.authorizer = authorizer
-		self.hostname = hostname
+
+		if hostname is None:
+			self.hostname = socket.gethostname()
+		else:
+			self.hostname = hostname
+
 		# statistics
 		self.total_sessions = counter()
 		self.closed_sessions = counter()
@@ -1053,8 +1055,7 @@ if os.name == 'posix':
 		import sys
 		fs = ftp_server (
 			unix_authorizer(),
-			HOSTNAME,
-			string.atoi (port)
+			port=string.atoi (port)
 			)
 		try:
 			asyncore.loop()

ZServer/medusa/http_server.py

@@ -9,7 +9,7 @@
 # interested in using this software in a commercial context, or in
 # purchasing support, please contact the author.
 
-RCS_ID =  '$Id: http_server.py,v 1.6 1999/04/09 00:37:33 amos Exp $'
+RCS_ID =  '$Id: http_server.py,v 1.7 1999/05/26 02:08:30 amos Exp $'
 
 # python modules
 import os
@@ -215,6 +215,12 @@ class http_request:
 					wrap_in_chunking = 1
 				else:
 					close_it = 1
+		elif self.version is None:
+			# Although we don't *really* support http/0.9 (because we'd have to
+			# use \r\n as a terminator, and it would just yuck up a lot of stuff)
+			# it's very common for developers to not want to type a version number
+			# when using telnet to debug a server.
+			close_it = 1
 					
 		outgoing_header = producers.simple_producer (self.build_reply_header())
 
@@ -388,9 +394,25 @@ class http_channel (asynchat.async_chat):
 		return result
 
 	def recv (self, buffer_size):
-		result = asynchat.async_chat.recv (self, buffer_size)
-		self.server.bytes_in.increment (len(result))
-		return result
+		try:
+			result = asynchat.async_chat.recv (self, buffer_size)
+			self.server.bytes_in.increment (len(result))
+			return result
+		except MemoryError:
+			# --- Save a Trip to Your Service Provider ---
+			# It's possible for a process to eat up all the memory of
+			# the machine, and put it in an extremely wedged state,
+			# where medusa keeps running and can't be shut down.  This
+			# is where MemoryError tends to get thrown, though of
+			# course it could get thrown elsewhere.
+			sys.exit ("Out of Memory!")
+
+	def handle_error (self):
+		t, v = sys.exc_info()[:2]
+		if t is SystemExit:
+			raise t, v
+		else:
+			asynchat.async_chat.handle_error (self)
 
 	def log (self, *args):
 		pass

ZServer/medusa/resolver.py

@@ -4,7 +4,8 @@
 #	Author: Sam Rushing <rushing@nightmare.com>
 #
 
-RCS_ID =  '$Id: resolver.py,v 1.2 1999/04/09 00:37:33 amos Exp $'
+RCS_ID =  '$Id: resolver.py,v 1.3 1999/05/26 02:08:30 amos Exp $'
+
 
 # Fast, low-overhead asynchronous name resolver.  uses 'pre-cooked'
 # DNS requests, unpacks only as much as it needs of the reply.
@@ -12,6 +13,11 @@ RCS_ID =  '$Id: resolver.py,v 1.2 1999/04/09 00:37:33 amos Exp $'
 # see rfc1035 for details
 
 import string
+import asyncore
+import socket
+import sys
+import time
+from counter import counter
 
 VERSION = string.split(RCS_ID)[2]
 
@@ -177,11 +183,6 @@ def unpack_ptr_reply (r):
 		return 0, None
 
 
-from counter import counter
-import asyncore
-import socket
-import sys
-
 # This is a UDP (datagram) resolver.
 
 #
@@ -202,6 +203,7 @@ class resolver (asyncore.dispatcher):
 		self.create_socket (socket.AF_INET, socket.SOCK_DGRAM)
 		self.server = server
 		self.request_map = {}
+		self.last_reap_time = int(time.time())      # reap every few minutes
 
 	def writable (self):
 		return 0
@@ -213,18 +215,38 @@ class resolver (asyncore.dispatcher):
 		print 'closing!'
 		self.close()
 
+	def handle_error (self):      # don't close the connection on error
+		(file,fun,line), t, v, tbinfo = asyncore.compact_traceback()
+		print 'Problem with DNS lookup (%s:%s %s)' % (t, v, tbinfo)
+
 	def get_id (self):
 		return (self.id.as_long() % (1<<16))
 
+	def reap (self):          # find DNS requests that have timed out
+		now = int(time.time())
+		if now - self.last_reap_time > 180:        # reap every 3 minutes
+			self.last_reap_time = now              # update before we forget
+			for k,(host,unpack,callback,when) in self.request_map.items():
+				if now - when > 180:               # over 3 minutes old
+					del self.request_map[k]
+					try:                           # same code as in handle_read
+						callback (host, 0, None)   # timeout val is (0,None) 
+					except:
+						(file,fun,line), t, v, tbinfo = asyncore.compact_traceback()
+						print t,v,tbinfo
+
 	def resolve (self, host, callback):
+		self.reap()                                # first, get rid of old guys
 		self.socket.sendto (
 			fast_address_request (host, self.get_id()),
 			(self.server, 53)
 			)
-		self.request_map [self.get_id()] = host, unpack_address_reply, callback
+		self.request_map [self.get_id()] = (
+			host, unpack_address_reply, callback, int(time.time()))
 		self.id.increment()
 
 	def resolve_ptr (self, host, callback):
+		self.reap()                                # first, get rid of old guys
 		ip = string.split (host, '.')
 		ip.reverse()
 		ip = string.join (ip, '.') + '.in-addr.arpa'
@@ -232,7 +254,8 @@ class resolver (asyncore.dispatcher):
 			fast_ptr_request (ip, self.get_id()),
 			(self.server, 53)
 			)
-		self.request_map [self.get_id()] = host, unpack_ptr_reply, callback
+		self.request_map [self.get_id()] = (
+			host, unpack_ptr_reply, callback, int(time.time()))
 		self.id.increment()
 
 	def handle_read (self):
@@ -241,7 +264,7 @@ class resolver (asyncore.dispatcher):
 		# that <whence> is the server we sent the request to.
 		id = (ord(reply[0])<<8) + ord(reply[1])
 		if self.request_map.has_key (id):
-			host, unpack, callback = self.request_map[id]
+			host, unpack, callback, when = self.request_map[id]
 			del self.request_map[id]
 			ttl, answer = unpack (reply)
 			try:
@@ -270,7 +293,6 @@ class rbl (resolver):
 		print repr(r)
 		return 0, rcode # (ttl, answer)
 
-import time
 
 class hooked_callback:
 	def __init__ (self, hook, callback):

lib/python/ZServer/medusa/asynchat.py

 # -*- Mode: Python; tab-width: 4 -*-
-#	$Id: asynchat.py,v 1.7 1999/04/09 00:37:33 amos Exp $
+#	$Id: asynchat.py,v 1.8 1999/05/26 02:08:29 amos Exp $
 #	Author: Sam Rushing <rushing@nightmare.com>
 
 # ======================================================================
@@ -99,7 +99,6 @@ class async_chat (asyncore.dispatcher):
 			elif type(terminator) == type(0):
 				# numeric terminator
 				n = terminator
-				lb = lb
 				if lb < n:
 					self.collect_incoming_data (self.ac_in_buffer)
 					self.ac_in_buffer = ''
@@ -159,7 +158,13 @@ class async_chat (asyncore.dispatcher):
 
 	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 len(self.ac_out_buffer) or len(self.producer_fifo) or (not self.connected)
+		# this is about twice as fast, though not as clear.
+		return not (
+			(self.ac_out_buffer is '') and
+			self.producer_fifo.is_empty() and
+			self.connected
+			)
 
 	def close_when_done (self):
 		"automatically close this channel once the outgoing queue is empty"
@@ -242,6 +247,9 @@ class fifo:
 	def __len__ (self):
 		return len(self.list)
 
+	def is_empty (self):
+		return self.list == []
+
 	def first (self):
 		return self.list[0]
 

lib/python/ZServer/medusa/asyncore.py

 # -*- Mode: Python; tab-width: 4 -*-
-# 	$Id: asyncore.py,v 1.2 1999/04/09 00:37:33 amos Exp $
+# 	$Id: asyncore.py,v 1.3 1999/05/26 02:08:30 amos Exp $
 #	Author: Sam Rushing <rushing@nightmare.com>
 
 # ======================================================================
@@ -37,17 +37,20 @@ if os.name == 'nt':
 	EALREADY	= 10037
 	ECONNRESET  = 10054
 	ENOTCONN	= 10057
+	ESHUTDOWN   = 10058
 else:
-	from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, ENOTCONN
+	from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, ENOTCONN, ESHUTDOWN
 
 socket_map = {}
 
 def poll (timeout=0.0):
 	if socket_map:
-		sockets = socket_map.keys()
-		r = filter (lambda x: x.readable(), sockets)
-		w = filter (lambda x: x.writable(), sockets)
-		e = []
+		r = []; w = []; e = []
+		for s in socket_map.keys():
+			if s.readable():
+				r.append (s)
+			if s.writable():
+				w.append (s)
 
 		(r,w,e) = select.select (r,w,e, timeout)
 
@@ -140,12 +143,14 @@ class dispatcher:
 			return '<__repr__ (self) failed for object at %x (addr=%s)>' % (id(self),ar)
 
 	def add_channel (self):
-		self.log ('adding channel %s' % self)
+		if __debug__:
+			self.log ('adding channel %s' % self)
 		socket_map [self] = 1
 
 	def del_channel (self):
 		if socket_map.has_key (self):
-			self.log ('closing channel %d:%s' % (self.fileno(), self))
+			if __debug__:
+				self.log ('closing channel %d:%s' % (self.fileno(), self))
 			del socket_map [self]
 
 	def create_socket (self, family, type):
@@ -155,7 +160,8 @@ class dispatcher:
 		self.add_channel()
 
 	def set_socket (self, socket):
-		self.socket = socket
+		# This is done so we can be called safely from __init__
+		self.__dict__['socket'] = socket
 		self.add_channel()
 
 	def set_reuse_addr (self):
@@ -245,7 +251,7 @@ class dispatcher:
 				return data
 		except socket.error, why:
 			# winsock sometimes throws ENOTCONN
-			if why[0] in [ECONNRESET, ENOTCONN]:
+			if why[0] in [ECONNRESET, ENOTCONN, ESHUTDOWN]:
 				self.handle_close()
 				return ''
 			else:
@@ -257,11 +263,9 @@ class dispatcher:
 
 	# cheap inheritance, used to pass all other attribute
 	# references to the underlying socket object.
+	# NOTE: this may be removed soon for performance reasons.
 	def __getattr__ (self, attr):
-		if attr != 'socket':
-			return getattr (self.socket, attr)
-		else:
-			raise AttributeError, attr
+		return getattr (self.socket, attr)
 
 	def log (self, message):
 		print 'log:', message
@@ -310,22 +314,28 @@ class dispatcher:
 		self.close()
 
 	def handle_expt (self):
-		self.log ('unhandled exception')
+		if __debug__:
+			self.log ('unhandled exception')
 
 	def handle_read (self):
-		self.log ('unhandled read event')
+		if __debug__:
+			self.log ('unhandled read event')
 
 	def handle_write (self):
-		self.log ('unhandled write event')
+		if __debug__:
+			self.log ('unhandled write event')
 
 	def handle_connect (self):
-		self.log ('unhandled connect event')
+		if __debug__:
+			self.log ('unhandled connect event')
 
 	def handle_accept (self):
-		self.log ('unhandled accept event')
+		if __debug__:
+			self.log ('unhandled accept event')
 
 	def handle_close (self):
-		self.log ('unhandled close event')
+		if __debug__:
+			self.log ('unhandled close event')
 		self.close()
 
 # ---------------------------------------------------------------------------

lib/python/ZServer/medusa/ftp_server.py

@@ -8,7 +8,7 @@
 # If you are interested in using this software in a commercial context,
 # or in purchasing support, please contact the author.
 
-RCS_ID =  '$Id: ftp_server.py,v 1.4 1999/04/29 23:36:09 amos Exp $'
+RCS_ID =  '$Id: ftp_server.py,v 1.5 1999/05/26 02:08:30 amos Exp $'
 
 # An extensible, configurable, asynchronous FTP server.
 # 
@@ -54,9 +54,6 @@ import time
 
 VERSION = string.split(RCS_ID)[2]
 
-IP_ADDRESS = socket.gethostbyname (socket.gethostname())
-HOSTNAME = socket.gethostbyaddr (IP_ADDRESS)[0]
-
 from counter import counter
 import producers
 import status_handler
@@ -286,7 +283,7 @@ class ftp_channel (asynchat.async_chat):
 		if pa:
 			if pa.ready:
 				# a connection has already been made.
-				conn, addr = self.passive_acceptor.ready
+				conn, addr = pa.ready
 				cdc = recv_channel (self, addr, fd)
 				cdc.set_socket (conn)
 				cdc.connected = 1
@@ -698,14 +695,19 @@ class ftp_server (asyncore.dispatcher):
 	def __init__ (
 		self,
 		authorizer,
-		hostname	=HOSTNAME,
+		hostname	=None,
 		port		=21,
 		resolver	=None,
 		logger_object=logger.file_logger (sys.stdout)
 		):
 		self.port = port
 		self.authorizer = authorizer
-		self.hostname = hostname
+
+		if hostname is None:
+			self.hostname = socket.gethostname()
+		else:
+			self.hostname = hostname
+
 		# statistics
 		self.total_sessions = counter()
 		self.closed_sessions = counter()
@@ -1053,8 +1055,7 @@ if os.name == 'posix':
 		import sys
 		fs = ftp_server (
 			unix_authorizer(),
-			HOSTNAME,
-			string.atoi (port)
+			port=string.atoi (port)
 			)
 		try:
 			asyncore.loop()

lib/python/ZServer/medusa/http_server.py

@@ -9,7 +9,7 @@
 # interested in using this software in a commercial context, or in
 # purchasing support, please contact the author.
 
-RCS_ID =  '$Id: http_server.py,v 1.6 1999/04/09 00:37:33 amos Exp $'
+RCS_ID =  '$Id: http_server.py,v 1.7 1999/05/26 02:08:30 amos Exp $'
 
 # python modules
 import os
@@ -215,6 +215,12 @@ class http_request:
 					wrap_in_chunking = 1
 				else:
 					close_it = 1
+		elif self.version is None:
+			# Although we don't *really* support http/0.9 (because we'd have to
+			# use \r\n as a terminator, and it would just yuck up a lot of stuff)
+			# it's very common for developers to not want to type a version number
+			# when using telnet to debug a server.
+			close_it = 1
 					
 		outgoing_header = producers.simple_producer (self.build_reply_header())
 
@@ -388,9 +394,25 @@ class http_channel (asynchat.async_chat):
 		return result
 
 	def recv (self, buffer_size):
-		result = asynchat.async_chat.recv (self, buffer_size)
-		self.server.bytes_in.increment (len(result))
-		return result
+		try:
+			result = asynchat.async_chat.recv (self, buffer_size)
+			self.server.bytes_in.increment (len(result))
+			return result
+		except MemoryError:
+			# --- Save a Trip to Your Service Provider ---
+			# It's possible for a process to eat up all the memory of
+			# the machine, and put it in an extremely wedged state,
+			# where medusa keeps running and can't be shut down.  This
+			# is where MemoryError tends to get thrown, though of
+			# course it could get thrown elsewhere.
+			sys.exit ("Out of Memory!")
+
+	def handle_error (self):
+		t, v = sys.exc_info()[:2]
+		if t is SystemExit:
+			raise t, v
+		else:
+			asynchat.async_chat.handle_error (self)
 
 	def log (self, *args):
 		pass

lib/python/ZServer/medusa/resolver.py

@@ -4,7 +4,8 @@
 #	Author: Sam Rushing <rushing@nightmare.com>
 #
 
-RCS_ID =  '$Id: resolver.py,v 1.2 1999/04/09 00:37:33 amos Exp $'
+RCS_ID =  '$Id: resolver.py,v 1.3 1999/05/26 02:08:30 amos Exp $'
+
 
 # Fast, low-overhead asynchronous name resolver.  uses 'pre-cooked'
 # DNS requests, unpacks only as much as it needs of the reply.
@@ -12,6 +13,11 @@ RCS_ID =  '$Id: resolver.py,v 1.2 1999/04/09 00:37:33 amos Exp $'
 # see rfc1035 for details
 
 import string
+import asyncore
+import socket
+import sys
+import time
+from counter import counter
 
 VERSION = string.split(RCS_ID)[2]
 
@@ -177,11 +183,6 @@ def unpack_ptr_reply (r):
 		return 0, None
 
 
-from counter import counter
-import asyncore
-import socket
-import sys
-
 # This is a UDP (datagram) resolver.
 
 #
@@ -202,6 +203,7 @@ class resolver (asyncore.dispatcher):
 		self.create_socket (socket.AF_INET, socket.SOCK_DGRAM)
 		self.server = server
 		self.request_map = {}
+		self.last_reap_time = int(time.time())      # reap every few minutes
 
 	def writable (self):
 		return 0
@@ -213,18 +215,38 @@ class resolver (asyncore.dispatcher):
 		print 'closing!'
 		self.close()
 
+	def handle_error (self):      # don't close the connection on error
+		(file,fun,line), t, v, tbinfo = asyncore.compact_traceback()
+		print 'Problem with DNS lookup (%s:%s %s)' % (t, v, tbinfo)
+
 	def get_id (self):
 		return (self.id.as_long() % (1<<16))
 
+	def reap (self):          # find DNS requests that have timed out
+		now = int(time.time())
+		if now - self.last_reap_time > 180:        # reap every 3 minutes
+			self.last_reap_time = now              # update before we forget
+			for k,(host,unpack,callback,when) in self.request_map.items():
+				if now - when > 180:               # over 3 minutes old
+					del self.request_map[k]
+					try:                           # same code as in handle_read
+						callback (host, 0, None)   # timeout val is (0,None) 
+					except:
+						(file,fun,line), t, v, tbinfo = asyncore.compact_traceback()
+						print t,v,tbinfo
+
 	def resolve (self, host, callback):
+		self.reap()                                # first, get rid of old guys
 		self.socket.sendto (
 			fast_address_request (host, self.get_id()),
 			(self.server, 53)
 			)
-		self.request_map [self.get_id()] = host, unpack_address_reply, callback
+		self.request_map [self.get_id()] = (
+			host, unpack_address_reply, callback, int(time.time()))
 		self.id.increment()
 
 	def resolve_ptr (self, host, callback):
+		self.reap()                                # first, get rid of old guys
 		ip = string.split (host, '.')
 		ip.reverse()
 		ip = string.join (ip, '.') + '.in-addr.arpa'
@@ -232,7 +254,8 @@ class resolver (asyncore.dispatcher):
 			fast_ptr_request (ip, self.get_id()),
 			(self.server, 53)
 			)
-		self.request_map [self.get_id()] = host, unpack_ptr_reply, callback
+		self.request_map [self.get_id()] = (
+			host, unpack_ptr_reply, callback, int(time.time()))
 		self.id.increment()
 
 	def handle_read (self):
@@ -241,7 +264,7 @@ class resolver (asyncore.dispatcher):
 		# that <whence> is the server we sent the request to.
 		id = (ord(reply[0])<<8) + ord(reply[1])
 		if self.request_map.has_key (id):
-			host, unpack, callback = self.request_map[id]
+			host, unpack, callback, when = self.request_map[id]
 			del self.request_map[id]
 			ttl, answer = unpack (reply)
 			try:
@@ -270,7 +293,6 @@ class rbl (resolver):
 		print repr(r)
 		return 0, rcode # (ttl, answer)
 
-import time
 
 class hooked_callback:
 	def __init__ (self, hook, callback):