Command handling in extra klassen ausgelagert

fakeftp.py

@@ -3,8 +3,9 @@ import threading
 import socket
 from random import randint
 import datetime
-
+class Utils:
-def mask(rights):
+	@staticmethod
+	def mask(rights):
 		m = ""
 		if rights&4 != 0:
 			m += "r"
@@ -23,9 +24,18 @@ def mask(rights):
 
 		return m
 
-def _r( (u,g,o) ):
+	@staticmethod
+	def _r( (u,g,o) ):
 		return ( (u&7) << 6 ) + ( (g&7) << 3 ) + (o&7)
 
+class Logger:
+	def log(self, handler, message):
+		pass
+
+class StdoutLogger:
+	def log(self, handler, message):
+		print "[%s] %s" % (handler.client_address[0],message)
+
 class FSNode:
 	def __init__(self,name,owner="nobody",group="nobody",rights=(6,4,4),size=0, iun=1):
 		self.name = name
@@ -33,11 +43,11 @@ class FSNode:
 		self.group = group
 
 		if type(rights) == tuple and len(rights) == 3:
-			self.rights = _r( rights )
+			self.rights = Utils._r( rights )
 		elif type(rights) == int:
 			self.rights = rights
 		else:
-			self.rights = _r( (6,4,4) )
+			self.rights = Utils._r( (6,4,4) )
 
 		self.size = size
 
@@ -86,9 +96,9 @@ class FSNode:
 			m += "-"
 
 		rights = self.get_rights()
-		m += mask((rights >> 6)&7)
+		m += Utils.mask((rights >> 6)&7)
-		m += mask((rights >> 3)&7)
+		m += Utils.mask((rights >> 3)&7)
-		m += mask(rights&7)
+		m += Utils.mask(rights&7)
 
 		return m
 
@@ -340,6 +350,10 @@ class SystemTypeMessage(FTPMessage):
 	def __init__(self, sys="UNIX",typ="L8"):
 		FTPMessage.__init__(self,"215","%s Type: %s" % ( sys.upper(), typ ))
 
+class FatalServerErrorMessage(FTPMessage):
+	def __init__(self):
+		FTPMessage.__init__(self, "421", "Fatal server error")
+
 # Data Connection Handler
 class NListHandler:
 	def __init__(self, directory, handler):
@@ -381,148 +395,246 @@ class RetrieveHandler:
 		self.node.send_content(socket)
 		self.handler.send( EndFileRetrieve() )
 
-# State classes
+# CommandHandler classes
-class State:
+class CommandHandler:
+	cmd = None
 	def process(self, handler, message):
 		pass
 
-class MainState(State):
+class ForbiddenCommandHandler(CommandHandler):
 	def process(self, handler, message):
-		if message.cmd == "QUIT":
+		if hasattr(self,'log'):
-			handler.debug( "Quitting" )
+			handler.log(self.log % message.parameter)
-			handler.send( QuitMessage() )
+		handler.send( OperationNotPermittedMessage() )
-			handler.running = False
+
-		else:
+class UnknownCommandHandler(CommandHandler):
+	def process(self, handler, message):
+		handler.log("Unknown command %s" % message.cmd)
 		handler.send( InvalidCommandMessage(message.cmd) )
 
-class NonAuthorizedState(MainState):
+class QuitCommandHandler(CommandHandler):
+	cmd = "QUIT"
 	def process(self, handler, message):
-		if message.cmd == "USER":
+		handler.log("Client quits")
-			handler.debug("Setting user to %s" % message.parameter)
+		handler.send( QuitMessage() )
+		handler.running = False
+
+class UserCommandHandler(CommandHandler):
+	cmd = "USER"
+	def process(self, handler, message):
+		handler.log("Setting user to %s" % message.parameter)
 		handler.user = message.parameter
 		handler.state = AuthorizingState()
 		handler.send( PasswordRequiredMessage(handler.user) )
-		else:
-			MainState.process(self, handler, message)
 
-class AuthorizingState(MainState):
+class PassCommandHandler(CommandHandler):
+	cmd = "PASS"
 	def process(self, handler, message):
-		if message.cmd == "USER":
-			handler.debug("Changing user to %s" % message.parameter)
-			handler.user = message.parameter
-			handler.send( PasswordRequiredMessage(handler.user) )
-		elif message.cmd == "PASS":
 		password = message.parameter
 		if handler.authorizer.authorize(handler.user, password, handler):
-				handler.debug("User login %s successful using password %s" % (handler.user,password))
+			handler.log("User login %s successful using password %s" % (handler.user,password))
 			handler.state = AuthorizedState()
 			handler.send( AuthorizationSuccessfulMessage() )
 		else:
-				handler.debug("User login %s failed using password %s" % (handler.user, password) )
+			handler.log("User login %s failed using password %s" % (handler.user, password) )
 			handler.state = NonAuthorizedState()
 			handler.send( AuthorizationFailedMessage() )
-		else:
-			MainState.process(self, handler, message)
 
-class AuthorizedState(MainState):
+class PasvCommandHandler(CommandHandler):
+	cmd = "PASV"
 	def process(self, handler, message):
-		if message.cmd == "PASV":
 		addr = handler.createPassiveDataConnection()
-			handler.debug("Created passive data connection")
+		handler.log("Create passive data connection")
 		handler.send( EnteringPassiveModeMessage( addr ) )
-		elif message.cmd == "DELE":
+
-			handler.debug( "Attempt to delete file %s" % message.parameter )
+class PortCommandHandler(CommandHandler):
-			handler.send( OperationNotPermittedMessage() )
+	cmd = "PORT"
-		elif message.cmd == "RMD":
+	def process(self, handler, message):
-			handler.debug( "Attempt to delete directory %s" % message.parameter )
-			handler.send( OperationNotPermittedMessage() )
-		elif message.cmd == "RNFR":
-			handler.debug( "Attempt to rename %s" % message.parameter )
-			handler.send( OperationNotPermittedMessage() )
-		elif message.cmd == "RNTO":
-			handler.debug( "Attempt to rename to %s" % message.parameter )
-			handler.send( OperationNotPermittedMessage() )
-		elif message.cmd == "STOR":
-			handler.debug( "Attempt to store a file %s" % message.parameter )
-			handler.send( OperationNotPermittedMessage() )
-		elif message.cmd == "RETR":
-			node = handler.get_node(message.parameter)
-			if node.is_file():
-				if handler.runDataConnection( RetrieveHandler(node, handler) ):
-					handler.debug( "Retrieving file %s" % message.parameter )
-				else:
-					handler.send( UnableToBuildConnectionMessage() )
-			else:
-				handler.send( OperationNotPermittedMessage() )
-		elif message.cmd == "PORT":
 		hp = message.parameter.split(",")
 		if len(hp) != 6:
 			handler.send( InvalidParametersMessage() )
 			return
 
 		if int(hp[0]) == 10 or int(hp[0]) == 127 or int(hp[0]) == 192: #Prevent local scanning
-				handler.debug( "Attempt to port to local network." )
+			handler.log( "Attempt to port to local network." )
 			handler.send( InvalidPortCommandMessage() )
 			return
 
 		addr = ( ".".join(hp[:4]), int(hp[4])<<8+int(hp[5]) )
 
-			handler.debug( "Creating active data connection to %s:%d" % addr )
+		handler.log( "Creating active data connection to %s:%d" % addr )
 
 		handler.createActiveDataConnection(addr)
 
 		handler.send( CommandSuccessfulMessage("PORT") )
-		elif message.cmd == "LIST":
+
+class DeleteCommandHandler(ForbiddenCommandHandler):
+	cmd = "DELE"
+	log = "Attempt to delete file %s"
+
+class RemoveDirCommandHandler(ForbiddenCommandHandler):
+	cmd = "RMD"
+	log = "Attempt to delete directory %s"
+
+class RenameFromCommandHandler(ForbiddenCommandHandler):
+	cmd = "RNFR"
+	log = "Attempt to rename %s"
+
+class RenameToCommandHandler(ForbiddenCommandHandler):
+	cmd = "RNTO"
+	log = "Attempt to rename to %s"
+
+class StoreCommandHandler(ForbiddenCommandHandler):
+	cmd = "STOR"
+	log = "Attempt to store file %s"
+
+class RetrieveCommandHandler(CommandHandler):
+	cmd = "RETR"
+	def process(self, handler, message):
+		node = handler.get_node(message.parameter)
+		if node.is_file():
+			if handler.runDataConnection( RetrieveHandler(node, handler) ):
+				handler.log( "Retrieving file %s" % message.parameter )
+			else:
+				handler.send( UnableToBuildConnectionMessage() )
+		else:
+			handler.send( OperationNotPermittedMessage() )
+
+class ListCommandHandler(CommandHandler):
+	cmd = "LIST"
+	def process(self, handler, message):
 		if handler.runDataConnection(ListHandler(handler.currentDirectory, handler)):
-				handler.debug("Listing current directory")
+			handler.log("Listing current directory")
 		else:
 			handler.send( UnableToBuildConnectionMessage() )
-		elif message.cmd == "NLST":
+
+class SimpleListCommandHandler(CommandHandler):
+	cmd = "NLST"
+	def process(self, handler, message):
 		if handler.runDataConnection(NListHandler(handler.currentDirectory)):
-				handler.debug("Listing current directory (simple)")
+			handler.log("Listing current directory (simple)")
 		else:
 			handler.send( UnableToBuildConnectionMessage() )
-		elif message.cmd == "CWD":
+
+class ChangeWorkingDirectoryCommandHandler(CommandHandler):
+	cmd = "CWD"
+	def process(self, handler, message):
 		node = handler.get_node(message.parameter)
 		if node is None or not node.is_dir():
-				handler.debug("Error trying to switch into non-existent directory")
+			handler.log("Error trying to switch into non-existent directory")
 			handler.send( ChangeDirectoryFailedMessage() )
 		else:
 			handler.currentDirectory = node
-				handler.debug("Changed working directory to "+node.get_absolute_path())
+			handler.log("Changed working directory to "+node.get_absolute_path())
 			handler.send( ChangeDirectorySuccessfulMessage() )
-		elif message.cmd == "CDUP":
+
+class ChangeDirectoryUpCommandHandler(CommandHandler):
+	cmd = "CDUP"
+	def process(self, handler, message):
 		node = handler.currentDirectory.get_parent_directory()
 		if node is None or not node.is_dir():
-				handler.debug("Error trying to switch to non-existent parent directory")
+			handler.log("Error trying to switch to non-existent parent directory")
 		else:
-				handler.debug("Changed working directory to "+node.get_absolute_path())
+			handler.log("Changed working directory to "+node.get_absolute_path())
 			handler.currentDirectory = node
 		handler.send( ChangeDirectorySuccessfulMessage() )
-		elif message.cmd == "PWD":
+
-			handler.debug( "Printing working directory" )
+class PrintWorkingDirectoryCommandHandler(CommandHandler):
+	cmd = "PWD"
+	def process(self, handler, message):
+		handler.log( "Printing working directory" )
 		handler.send( WorkingDirectoryMessage(handler.currentDirectory.get_absolute_path()) )
-		elif message.cmd == "TYPE":
+
+class SetTypeCommandHandler(CommandHandler):
+	cmd = "TYPE"
+	def process(self, handler, message):
 		if message.parameter == "A":
-				handler.debug("Setting type to ASCII")
+			handler.log("Setting type to ASCII")
 			handler.send( TypeSetMessage(message.parameter) )
 		else:
-				handler.debug("Unrecognized type %s" % message.parameter)
+			handler.log("Unrecognized type %s" % message.parameter)
 			handler.send( InvalidCommandMessage("TYPE") )
-		elif message.cmd == "NOOP":
+
-			handler.debug("No operation")
+class NoOperationCommandHandler(CommandHandler):
+	cmd = "NOOP"
+	def process(self, handler, message):
+		handler.log("No operation")
 		handler.send( CommandSuccessfulMessage("NOOP") )
-		elif message.cmd == "SIZE":
+
-			handler.debug("Requested size of %s" % message.parameter)
+class SizeCommandHandler(CommandHandler):
+	cmd = "SIZE"
+	def process(self, handler, message):
+		handler.log("Requested size of %s" % message.parameter)
 		handler.send( CommandNotAllowedInAscii("SIZE") )
-		elif message.cmd == "ABOR":
+
-			handler.debug("Aborting data connection")
+class AbortCommandHandler(CommandHandler):
+	cmd = "ABOR"
+	def process(self, handler, message):
+		handler.log("Aborting data connection")
 		handler.send( AbortSuccessfulMessage() )
-		elif message.cmd == "SYST":
+
-			handler.debug("Requested system type")
+class SystemTypeCommandHandler(CommandHandler):
+	cmd = "SYST"
+	def process(self, handler, message):
+		handler.log("Requested system type")
 		handler.send( SystemTypeMessage() )
-		else:
+
-			MainState.process(self, handler, message)
+# State classes
+class State:
+	handlers = []
+	defaulthandler = UnknownCommandHandler()
+
+	@classmethod
+	def get_handlers(cls):
+		hlds = [] + cls.handlers
+		for b in cls.__bases__:
+			hlds += b.get_handlers()
+		return hlds
+
+	@classmethod
+	def get_handler(cls, cmd):
+		for hld in cls.get_handlers():
+			if hld.cmd == cmd:
+				return hld
+		return cls.defaulthandler
+
+	def process(self, handler, message):
+		try:
+			self.get_handler(message.cmd).process(handler,message)
+		except Exception:
+			handler.send( FatalServerErrorMessage() )
+			handler.running = False
+		
+
+class BaseState(State):
+	handlers = [ QuitCommandHandler(), NoOperationCommandHandler() ]
+
+class NonAuthorizedState(BaseState):
+	handlers = [ UserCommandHandler() ]
+
+class AuthorizingState(NonAuthorizedState):
+	handlers = [ PassCommandHandler() ]
+
+class AuthorizedState(BaseState):
+	handlers = [
+		PasvCommandHandler(),
+		PortCommandHandler(),
+		DeleteCommandHandler(),
+		RemoveDirCommandHandler(),
+		RenameToCommandHandler(),
+		RenameFromCommandHandler(),
+		StoreCommandHandler(),
+		RetrieveCommandHandler(),
+		ListCommandHandler(),
+		SimpleListCommandHandler(),
+		ChangeWorkingDirectoryCommandHandler(),
+		ChangeDirectoryUpCommandHandler(),
+		PrintWorkingDirectoryCommandHandler(),
+		SetTypeCommandHandler(),
+		SizeCommandHandler(),
+		AbortCommandHandler(),
+		SystemTypeCommandHandler()
+	]
 
 class LineReader:
 	def __init__(self):
@@ -542,8 +654,10 @@ class LineReader:
 			pos = self.buf.find("\n")
 
 class FTPHandler(SocketServer.BaseRequestHandler):
-	def debug(self, text):
+	logger = StdoutLogger()
-		print ("[%s] " % self.client_address[0]) + text
+
+	def log(self, message):
+		self.logger.log(self,message)
 
 	def send(self, message):
 		self.request.send( str(message) )
@@ -594,7 +708,7 @@ class FTPHandler(SocketServer.BaseRequestHandler):
 
 		self.state = NonAuthorizedState()
 
-		self.debug("Client connected");
+		self.log("Client connected");
 
 		self.send( WelcomeMessage() )
 
@@ -613,7 +727,7 @@ class FTPHandler(SocketServer.BaseRequestHandler):
 				message = FTPMessage.parse(line)
 				self.state.process(self,message)
 
-		self.debug("Client disconnected")
+		self.log("Client disconnected")
 
 handler = FTPHandler
 handler.authorizer = AnonymousAuthorizer()