#!/usr/bin/python
import SocketServer, string, os, socket

class Finger(SocketServer.StreamRequestHandler):
	def handle(self):
		""" get username requested, return lookup results """
		# drop privs
		os.setregid(65534, 65534)
		os.setreuid(65534, 65534)

		# do lookup
		username = self.rfile.readline(512).strip()
		self.wfile.write( self.find_user( username ) )

	def find_user(self, userid):
		""" grep user on system """
		ret = []
		f = os.popen("who | grep %s" % userid)
		for line in f:
			ret.extend( [ line.strip(), "\r\n" ] )
		f.close()
		if len(ret) == 0:
			ret.append("Sorry, they are not logged in.\r\n")
		return ''.join(ret)

class ReusableTCPServer(SocketServer.ForkingTCPServer):
	def server_bind(self):
		self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
		self.socket.bind(self.server_address)

if __name__ == '__main__':
	server = ReusableTCPServer( ('', 79), Finger)
	server.serve_forever()