Demo/pysvr/pysvr.py

   1 #! /usr/bin/env python
   2
   3 """A multi-threaded telnet-like server that gives a Python prompt.
   4
   5 This is really a prototype for the same thing in C.
   6
   7 Usage: pysvr.py [port]
   8
   9 For security reasons, it only accepts requests from the current host.
  10 This can still be insecure, but restricts violations from people who
  11 can log in on your machine.  Use with caution!
  12
  13 """
  14
  15 import sys, os, string, getopt, thread, socket, traceback
  16
  17 PORT = 4000                             # Default port
  18
  19 def main():
  20     try:
  21         opts, args = getopt.getopt(sys.argv[1:], "")
  22         if len(args) > 1:
  23             raise getopt.error, "Too many arguments."
  24     except getopt.error, msg:
  25         usage(msg)
  26     for o, a in opts:
  27         pass
  28     if args:
  29         try:
  30             port = string.atoi(args[0])
  31         except ValueError, msg:
  32             usage(msg)
  33     else:
  34         port = PORT
  35     main_thread(port)
  36
  37 def usage(msg=None):
  38     sys.stdout = sys.stderr
  39     if msg:
  40         print msg
  41     print "\n", __doc__,
  42     sys.exit(2)
  43
  44 def main_thread(port):
  45     sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  46     sock.bind(("", port))
  47     sock.listen(5)
  48     print "Listening on port", port, "..."
  49     while 1:
  50         (conn, addr) = sock.accept()
  51         if addr[0] != conn.getsockname()[0]:
  52             conn.close()
  53             print "Refusing connection from non-local host", addr[0], "."
  54             continue
  55         thread.start_new_thread(service_thread, (conn, addr))
  56         del conn, addr
  57
  58 def service_thread(conn, addr):
  59     (caddr, cport) = addr
  60     print "Thread %s has connection from %s.\n" % (str(thread.get_ident()),
  61                                                    caddr),
  62     stdin = conn.makefile("r")
  63     stdout = conn.makefile("w", 0)
  64     run_interpreter(stdin, stdout)
  65     print "Thread %s is done.\n" % str(thread.get_ident()),
  66
  67 def run_interpreter(stdin, stdout):
  68     globals = {}
  69     try:
  70         str(sys.ps1)
  71     except:
  72         sys.ps1 = ">>> "
  73     source = ""
  74     while 1:
  75         stdout.write(sys.ps1)
  76         line = stdin.readline()
  77         if line[:2] == '\377\354':
  78             line = ""
  79         if not line and not source:
  80             break
  81         if line[-2:] == '\r\n':
  82             line = line[:-2] + '\n'
  83         source = source + line
  84         try:
  85             code = compile_command(source)
  86         except SyntaxError, err:
  87             source = ""
  88             traceback.print_exception(SyntaxError, err, None, file=stdout)
  89             continue
  90         if not code:
  91             continue
  92         source = ""
  93         try:
  94             run_command(code, stdin, stdout, globals)
  95         except SystemExit, how:
  96             if how:
  97                 try:
  98                     how = str(how)
  99                 except:
 100                     how = ""
 101                 stdout.write("Exit %s\n" % how)
 102             break
 103     stdout.write("\nGoodbye.\n")
 104
 105 def run_command(code, stdin, stdout, globals):
 106     save = sys.stdin, sys.stdout, sys.stderr
 107     try:
 108         sys.stdout = sys.stderr = stdout
 109         sys.stdin = stdin
 110         try:
 111             exec code in globals
 112         except SystemExit, how:
 113             raise SystemExit, how, sys.exc_info()[2]
 114         except:
 115             type, value, tb = sys.exc_info()
 116             if tb: tb = tb.tb_next
 117             traceback.print_exception(type, value, tb)
 118             del tb
 119     finally:
 120         sys.stdin, sys.stdout, sys.stderr = save
 121
 122 from code import compile_command
 123
 124 main()