text: r"""TELNET client class.
  
  Based on RFC 854: TELNET Protocol Specification, by J. Postel and
  J. Reynolds
  
  Example:
  
  >>> from telnetlib import Telnet
  >>> tn = Telnet('www.python.org', 79)   # connect to finger port
  >>> tn.write('guido\r\n')
  >>> print tn.read_all()
  Login       Name               TTY         Idle    When    Where
  guido    Guido van Rossum      pts/2        <Dec  2 11:10> snag.cnri.reston..
  
  >>>
  
  Note that read_all() won't read until eof -- it just reads some data
  -- but it guarantees to read at least one byte unless EOF is hit.
  
  It is possible to pass a Telnet object to select.select() in order to
  wait until more data is available.  Note that in this case,
  read_eager() may return '' even if there was data on the socket,
  because the protocol negotiation may have eaten the data.  This is why
  EOFError is needed in some cases to distinguish between "no data" and
  "connection closed" (since the socket also appears ready for reading
  when it is closed).
  
  To do:
  - option negotiation
  - timeout should be intrinsic to the connection object instead of an
    option on one of the read calls only
  
  """
  
  
  # Imported modules
  import errno
  import sys
  import socket
  import select
  
  __all__ = ["Telnet"]
  
  # Tunable parameters
  DEBUGLEVEL = 0
  
  # Telnet protocol defaults
  TELNET_PORT = 23
  
  # Telnet protocol characters (don't change)
  IAC  = chr(255) # "Interpret As Command"
  DONT = chr(254)
  DO   = chr(253)
  WONT = chr(252)
  WILL = chr(251)
  theNULL = chr(0)
  
  SE  = chr(240)  # Subnegotiation End
  NOP = chr(241)  # No Operation
  DM  = chr(242)  # Data Mark
  BRK = chr(243)  # Break
  IP  = chr(244)  # Interrupt process
  AO  = chr(245)  # Abort output
  AYT = chr(246)  # Are You There
  EC  = chr(247)  # Erase Character
  EL  = chr(248)  # Erase Line
  GA  = chr(249)  # Go Ahead
  SB =  chr(250)  # Subnegotiation Begin
  
  
  # Telnet protocol options code (don't change)
  # These ones all come from arpa/telnet.h
  BINARY = chr(0) # 8-bit data path
  ECHO = chr(1) # echo
  RCP = chr(2) # prepare to reconnect
  SGA = chr(3) # suppress go ahead
  NAMS = chr(4) # approximate message size
  STATUS = chr(5) # give status
  TM = chr(6) # timing mark
  RCTE = chr(7) # remote controlled transmission and echo
  NAOL = chr(8) # negotiate about output line width
  NAOP = chr(9) # negotiate about output page size
  NAOCRD = chr(10) # negotiate about CR disposition
  NAOHTS = chr(11) # negotiate about horizontal tabstops
  NAOHTD = chr(12) # negotiate about horizontal tab disposition
  NAOFFD = chr(13) # negotiate about formfeed disposition
  NAOVTS = chr(14) # negotiate about vertical tab stops
  NAOVTD = chr(15) # negotiate about vertical tab disposition
  NAOLFD = chr(16) # negotiate about output LF disposition
  XASCII = chr(17) # extended ascii character set
  LOGOUT = chr(18) # force logout
  BM = chr(19) # byte macro
  DET = chr(20) # data entry terminal
  SUPDUP = chr(21) # supdup protocol
  SUPDUPOUTPUT = chr(22) # supdup output
  SNDLOC = chr(23) # send location
  TTYPE = chr(24) # terminal type
  EOR = chr(25) # end or record
  TUID = chr(26) # TACACS user identification
  OUTMRK = chr(27) # output marking
  TTYLOC = chr(28) # terminal location number
  VT3270REGIME = chr(29) # 3270 regime
  X3PAD = chr(30) # X.3 PAD
  NAWS = chr(31) # window size
  TSPEED = chr(32) # terminal speed
  LFLOW = chr(33) # remote flow control
  LINEMODE = chr(34) # Linemode option
  XDISPLOC = chr(35) # X Display Location
  OLD_ENVIRON = chr(36) # Old - Environment variables
  AUTHENTICATION = chr(37) # Authenticate
  ENCRYPT = chr(38) # Encryption option
  NEW_ENVIRON = chr(39) # New - Environment variables
  # the following ones come from
  # http://www.iana.org/assignments/telnet-options
  # Unfortunately, that document does not assign identifiers
  # to all of them, so we are making them up
  TN3270E = chr(40) # TN3270E
  XAUTH = chr(41) # XAUTH
  CHARSET = chr(42) # CHARSET
  RSP = chr(43) # Telnet Remote Serial Port
  COM_PORT_OPTION = chr(44) # Com Port Control Option
  SUPPRESS_LOCAL_ECHO = chr(45) # Telnet Suppress Local Echo
  TLS = chr(46) # Telnet Start TLS
  KERMIT = chr(47) # KERMIT
  SEND_URL = chr(48) # SEND-URL
  FORWARD_X = chr(49) # FORWARD_X
  PRAGMA_LOGON = chr(138) # TELOPT PRAGMA LOGON
  SSPI_LOGON = chr(139) # TELOPT SSPI LOGON
  PRAGMA_HEARTBEAT = chr(140) # TELOPT PRAGMA HEARTBEAT
  EXOPL = chr(255) # Extended-Options-List
  NOOPT = chr(0)
  
  class Telnet:
  
      """Telnet interface class.
  
      An instance of this class represents a connection to a telnet
      server.  The instance is initially not connected; the open()
      method must be used to establish a connection.  Alternatively, the
      host name and optional port number can be passed to the
      constructor, too.
  
      Don't try to reopen an already connected instance.
  
      This class has many read_*() methods.  Note that some of them
      raise EOFError when the end of the connection is read, because
      they can return an empty string for other reasons.  See the
      individual doc strings.
  
      read_until(expected, [timeout])
          Read until the expected string has been seen, or a timeout is
          hit (default is no timeout); may block.
  
      read_all()
          Read all data until EOF; may block.
  
      read_some()
          Read at least one byte or EOF; may block.
  
      read_very_eager()
          Read all data available already queued or on the socket,
          without blocking.
  
      read_eager()
          Read either data already queued or some data available on the
          socket, without blocking.
  
      read_lazy()
          Read all data in the raw queue (processing it first), without
          doing any socket I/O.
  
      read_very_lazy()
          Reads all data in the cooked queue, without doing any socket
          I/O.
  
      read_sb_data()
          Reads available data between SB ... SE sequence. Don't block.
  
      set_option_negotiation_callback(callback)
          Each time a telnet option is read on the input flow, this callback
          (if set) is called with the following parameters :
          callback(telnet socket, command, option)
              option will be chr(0) when there is no option.
          No other action is done afterwards by telnetlib.
  
      """
  
      def __init__(self, host=None, port=0,
                   timeout=socket._GLOBAL_DEFAULT_TIMEOUT):
          """Constructor.
  
          When called without arguments, create an unconnected instance.
          With a hostname argument, it connects the instance; port number
          and timeout are optional.
          """
          self.debuglevel = DEBUGLEVEL
          self.host = host
          self.port = port
          self.timeout = timeout
          self.sock = None
          self.rawq = ''
          self.irawq = 0
          self.cookedq = ''
          self.eof = 0
          self.iacseq = '' # Buffer for IAC sequence.
          self.sb = 0 # flag for SB and SE sequence.
          self.sbdataq = ''
          self.option_callback = None
          self._has_poll = hasattr(select, 'poll')
          if host is not None:
              self.open(host, port, timeout)
  
      def open(self, host, port=0, timeout=socket._GLOBAL_DEFAULT_TIMEOUT):
          """Connect to a host.
  
          The optional second argument is the port number, which
          defaults to the standard telnet port (23).
  
          Don't try to reopen an already connected instance.
          """
          self.eof = 0
          if not port:
              port = TELNET_PORT
          self.host = host
          self.port = port
          self.timeout = timeout
          self.sock = socket.create_connection((host, port), timeout)
  
      def __del__(self):
          """Destructor -- close the connection."""
          self.close()
  
      def msg(self, msg, *args):
          """Print a debug message, when the debug level is > 0.
  
          If extra arguments are present, they are substituted in the
          message using the standard string formatting operator.
  
          """
          if self.debuglevel > 0:
              print 'Telnet(%s,%s):' % (self.host, self.port),
              if args:
                  print msg % args
              else:
                  print msg
  
      def set_debuglevel(self, debuglevel):
          """Set the debug level.
  
          The higher it is, the more debug output you get (on sys.stdout).
  
          """
          self.debuglevel = debuglevel
  
      def close(self):
          """Close the connection."""
          sock = self.sock
          self.sock = 0
          self.eof = 1
          self.iacseq = ''
          self.sb = 0
          if sock:
              sock.close()
  
      def get_socket(self):
          """Return the socket object used internally."""
          return self.sock
  
      def fileno(self):
          """Return the fileno() of the socket object used internally."""
          return self.sock.fileno()
  
      def write(self, buffer):
          """Write a string to the socket, doubling any IAC characters.
  
          Can block if the connection is blocked.  May raise
          socket.error if the connection is closed.
  
          """
          if IAC in buffer:
              buffer = buffer.replace(IAC, IAC+IAC)
          self.msg("send %r", buffer)
          self.sock.sendall(buffer)
  
      def read_until(self, match, timeout=None):
          """Read until a given string is encountered or until timeout.
  
          When no match is found, return whatever is available instead,
          possibly the empty string.  Raise EOFError if the connection
          is closed and no cooked data is available.
  
          """
          if self._has_poll:
              return self._read_until_with_poll(match, timeout)
          else:
              return self._read_until_with_select(match, timeout)
  
      def _read_until_with_poll(self, match, timeout):
          """Read until a given string is encountered or until timeout.
  
          This method uses select.poll() to implement the timeout.
          """
          n = len(match)
          call_timeout = timeout
          if timeout is not None:
              from time import time
              time_start = time()
          self.process_rawq()
          i = self.cookedq.find(match)
          if i < 0:
              poller = select.poll()
              poll_in_or_priority_flags = select.POLLIN | select.POLLPRI
              poller.register(self, poll_in_or_priority_flags)
              while i < 0 and not self.eof:
                  try:
                      # Poll takes its timeout in milliseconds.
                      ready = poller.poll(None if timeout is None
                                          else 1000 * call_timeout)
                  except select.error as e:
                      if e.errno == errno.EINTR:
                          if timeout is not None:
                              elapsed = time() - time_start
                              call_timeout = timeout-elapsed
                          continue
                      raise
                  for fd, mode in ready:
                      if mode & poll_in_or_priority_flags:
                          i = max(0, len(self.cookedq)-n)
                          self.fill_rawq()
                          self.process_rawq()
                          i = self.cookedq.find(match, i)
                  if timeout is not None:
                      elapsed = time() - time_start
                      if elapsed >= timeout:
                          break
                      call_timeout = timeout-elapsed
              poller.unregister(self)
          if i >= 0:
              i = i + n
              buf = self.cookedq[:i]
              self.cookedq = self.cookedq[i:]
              return buf
          return self.read_very_lazy()
  
      def _read_until_with_select(self, match, timeout=None):
          """Read until a given string is encountered or until timeout.
  
          The timeout is implemented using select.select().
          """
          n = len(match)
          self.process_rawq()
          i = self.cookedq.find(match)
          if i >= 0:
              i = i+n
              buf = self.cookedq[:i]
              self.cookedq = self.cookedq[i:]
              return buf
          s_reply = ([self], [], [])
          s_args = s_reply
          if timeout is not None:
              s_args = s_args + (timeout,)
              from time import time
              time_start = time()
          while not self.eof and select.select(*s_args) == s_reply:
              i = max(0, len(self.cookedq)-n)
              self.fill_rawq()
              self.process_rawq()
              i = self.cookedq.find(match, i)
              if i >= 0:
                  i = i+n
                  buf = self.cookedq[:i]
                  self.cookedq = self.cookedq[i:]
                  return buf
              if timeout is not None:
                  elapsed = time() - time_start
                  if elapsed >= timeout:
                      break
                  s_args = s_reply + (timeout-elapsed,)
          return self.read_very_lazy()
  
      def read_all(self):
          """Read all data until EOF; block until connection closed."""
          self.process_rawq()
          while not self.eof:
              self.fill_rawq()
              self.process_rawq()
          buf = self.cookedq
          self.cookedq = ''
          return buf
  
      def read_some(self):
          """Read at least one byte of cooked data unless EOF is hit.
  
          Return '' if EOF is hit.  Block if no data is immediately
          available.
  
          """
          self.process_rawq()
          while not self.cookedq and not self.eof:
              self.fill_rawq()
              self.process_rawq()
          buf = self.cookedq
          self.cookedq = ''
          return buf
  
      def read_very_eager(self):
          """Read everything that's possible without blocking in I/O (eager).
  
          Raise EOFError if connection closed and no cooked data
          available.  Return '' if no cooked data available otherwise.
          Don't block unless in the midst of an IAC sequence.
  
          """
          self.process_rawq()
          while not self.eof and self.sock_avail():
              self.fill_rawq()
              self.process_rawq()
          return self.read_very_lazy()
  
      def read_eager(self):
          """Read readily available data.
  
          Raise EOFError if connection closed and no cooked data
          available.  Return '' if no cooked data available otherwise.
          Don't block unless in the midst of an IAC sequence.
  
          """
          self.process_rawq()
          while not self.cookedq and not self.eof and self.sock_avail():
              self.fill_rawq()
              self.process_rawq()
          return self.read_very_lazy()
  
      def read_lazy(self):
          """Process and return data that's already in the queues (lazy).
  
          Raise EOFError if connection closed and no data available.
          Return '' if no cooked data available otherwise.  Don't block
          unless in the midst of an IAC sequence.
  
          """
          self.process_rawq()
          return self.read_very_lazy()
  
      def read_very_lazy(self):
          """Return any data available in the cooked queue (very lazy).
  
          Raise EOFError if connection closed and no data available.
          Return '' if no cooked data available otherwise.  Don't block.
  
          """
          buf = self.cookedq
          self.cookedq = ''
          if not buf and self.eof and not self.rawq:
              raise EOFError, 'telnet connection closed'
          return buf
  
      def read_sb_data(self):
          """Return any data available in the SB ... SE queue.
  
          Return '' if no SB ... SE available. Should only be called
          after seeing a SB or SE command. When a new SB command is
          found, old unread SB data will be discarded. Don't block.
  
          """
          buf = self.sbdataq
          self.sbdataq = ''
          return buf
  
      def set_option_negotiation_callback(self, callback):
          """Provide a callback function called after each receipt of a telnet option."""
          self.option_callback = callback
  
      def process_rawq(self):
          """Transfer from raw queue to cooked queue.
  
          Set self.eof when connection is closed.  Don't block unless in
          the midst of an IAC sequence.
  
          """
          buf = ['', '']
          try:
              while self.rawq:
                  c = self.rawq_getchar()
                  if not self.iacseq:
                      if c == theNULL:
                          continue
                      if c == "\021":
                          continue
                      if c != IAC:
                          buf[self.sb] = buf[self.sb] + c
                          continue
                      else:
                          self.iacseq += c
                  elif len(self.iacseq) == 1:
                      # 'IAC: IAC CMD [OPTION only for WILL/WONT/DO/DONT]'
                      if c in (DO, DONT, WILL, WONT):
                          self.iacseq += c
                          continue
  
                      self.iacseq = ''
                      if c == IAC:
                          buf[self.sb] = buf[self.sb] + c
                      else:
                          if c == SB: # SB ... SE start.
                              self.sb = 1
                              self.sbdataq = ''
                          elif c == SE:
                              self.sb = 0
                              self.sbdataq = self.sbdataq + buf[1]
                              buf[1] = ''
                          if self.option_callback:
                              # Callback is supposed to look into
                              # the sbdataq
                              self.option_callback(self.sock, c, NOOPT)
                          else:
                              # We can't offer automatic processing of
                              # suboptions. Alas, we should not get any
                              # unless we did a WILL/DO before.
                              self.msg('IAC %d not recognized' % ord(c))
                  elif len(self.iacseq) == 2:
                      cmd = self.iacseq[1]
                      self.iacseq = ''
                      opt = c
                      if cmd in (DO, DONT):
                          self.msg('IAC %s %d',
                              cmd == DO and 'DO' or 'DONT', ord(opt))
                          if self.option_callback:
                              self.option_callback(self.sock, cmd, opt)
                          else:
                              self.sock.sendall(IAC + WONT + opt)
                      elif cmd in (WILL, WONT):
                          self.msg('IAC %s %d',
                              cmd == WILL and 'WILL' or 'WONT', ord(opt))
                          if self.option_callback:
                              self.option_callback(self.sock, cmd, opt)
                          else:
                              self.sock.sendall(IAC + DONT + opt)
          except EOFError: # raised by self.rawq_getchar()
              self.iacseq = '' # Reset on EOF
              self.sb = 0
              pass
          self.cookedq = self.cookedq + buf[0]
          self.sbdataq = self.sbdataq + buf[1]
  
      def rawq_getchar(self):
          """Get next char from raw queue.
  
          Block if no data is immediately available.  Raise EOFError
          when connection is closed.
  
          """
          if not self.rawq:
              self.fill_rawq()
              if self.eof:
                  raise EOFError
          c = self.rawq[self.irawq]
          self.irawq = self.irawq + 1
          if self.irawq >= len(self.rawq):
              self.rawq = ''
              self.irawq = 0
          return c
  
      def fill_rawq(self):
          """Fill raw queue from exactly one recv() system call.
  
          Block if no data is immediately available.  Set self.eof when
          connection is closed.
  
          """
          if self.irawq >= len(self.rawq):
              self.rawq = ''
              self.irawq = 0
          # The buffer size should be fairly small so as to avoid quadratic
          # behavior in process_rawq() above
          buf = self.sock.recv(50)
          self.msg("recv %r", buf)
          self.eof = (not buf)
          self.rawq = self.rawq + buf
  
      def sock_avail(self):
          """Test whether data is available on the socket."""
          return select.select([self], [], [], 0) == ([self], [], [])
  
      def interact(self):
          """Interaction function, emulates a very dumb telnet client."""
          if sys.platform == "win32":
              self.mt_interact()
              return
          while 1:
              rfd, wfd, xfd = select.select([self, sys.stdin], [], [])
              if self in rfd:
                  try:
                      text = self.read_eager()
                  except EOFError:
                      print '*** Connection closed by remote host ***'
                      break
                  if text:
                      sys.stdout.write(text)
                      sys.stdout.flush()
              if sys.stdin in rfd:
                  line = sys.stdin.readline()
                  if not line:
                      break
                  self.write(line)
  
      def mt_interact(self):
          """Multithreaded version of interact()."""
          import thread
          thread.start_new_thread(self.listener, ())
          while 1:
              line = sys.stdin.readline()
              if not line:
                  break
              self.write(line)
  
      def listener(self):
          """Helper for mt_interact() -- this executes in the other thread."""
          while 1:
              try:
                  data = self.read_eager()
              except EOFError:
                  print '*** Connection closed by remote host ***'
                  return
              if data:
                  sys.stdout.write(data)
              else:
                  sys.stdout.flush()
  
      def expect(self, list, timeout=None):
          """Read until one from a list of a regular expressions matches.
  
          The first argument is a list of regular expressions, either
          compiled (re.RegexObject instances) or uncompiled (strings).
          The optional second argument is a timeout, in seconds; default
          is no timeout.
  
          Return a tuple of three items: the index in the list of the
          first regular expression that matches; the match object
          returned; and the text read up till and including the match.
  
          If EOF is read and no text was read, raise EOFError.
          Otherwise, when nothing matches, return (-1, None, text) where
          text is the text received so far (may be the empty string if a
          timeout happened).
  
          If a regular expression ends with a greedy match (e.g. '.*')
          or if more than one expression can match the same input, the
          results are undeterministic, and may depend on the I/O timing.
  
          """
          if self._has_poll:
              return self._expect_with_poll(list, timeout)
          else:
              return self._expect_with_select(list, timeout)
  
      def _expect_with_poll(self, expect_list, timeout=None):
          """Read until one from a list of a regular expressions matches.
  
          This method uses select.poll() to implement the timeout.
          """
          re = None
          expect_list = expect_list[:]
          indices = range(len(expect_list))
          for i in indices:
              if not hasattr(expect_list[i], "search"):
                  if not re: import re
                  expect_list[i] = re.compile(expect_list[i])
          call_timeout = timeout
          if timeout is not None:
              from time import time
              time_start = time()
          self.process_rawq()
          m = None
          for i in indices:
              m = expect_list[i].search(self.cookedq)
              if m:
                  e = m.end()
                  text = self.cookedq[:e]
                  self.cookedq = self.cookedq[e:]
                  break
          if not m:
              poller = select.poll()
              poll_in_or_priority_flags = select.POLLIN | select.POLLPRI
              poller.register(self, poll_in_or_priority_flags)
              while not m and not self.eof:
                  try:
                      ready = poller.poll(None if timeout is None
                                          else 1000 * call_timeout)
                  except select.error as e:
                      if e.errno == errno.EINTR:
                          if timeout is not None:
                              elapsed = time() - time_start
                              call_timeout = timeout-elapsed
                          continue
                      raise
                  for fd, mode in ready:
                      if mode & poll_in_or_priority_flags:
                          self.fill_rawq()
                          self.process_rawq()
                          for i in indices:
                              m = expect_list[i].search(self.cookedq)
                              if m:
                                  e = m.end()
                                  text = self.cookedq[:e]
                                  self.cookedq = self.cookedq[e:]
                                  break
                  if timeout is not None:
                      elapsed = time() - time_start
                      if elapsed >= timeout:
                          break
                      call_timeout = timeout-elapsed
              poller.unregister(self)
          if m:
              return (i, m, text)
          text = self.read_very_lazy()
          if not text and self.eof:
              raise EOFError
          return (-1, None, text)
  
      def _expect_with_select(self, list, timeout=None):
          """Read until one from a list of a regular expressions matches.
  
          The timeout is implemented using select.select().
          """
          re = None
          list = list[:]
          indices = range(len(list))
          for i in indices:
              if not hasattr(list[i], "search"):
                  if not re: import re
                  list[i] = re.compile(list[i])
          if timeout is not None:
              from time import time
              time_start = time()
          while 1:
              self.process_rawq()
              for i in indices:
                  m = list[i].search(self.cookedq)
                  if m:
                      e = m.end()
                      text = self.cookedq[:e]
                      self.cookedq = self.cookedq[e:]
                      return (i, m, text)
              if self.eof:
                  break
              if timeout is not None:
                  elapsed = time() - time_start
                  if elapsed >= timeout:
                      break
                  s_args = ([self.fileno()], [], [], timeout-elapsed)
                  r, w, x = select.select(*s_args)
                  if not r:
                      break
              self.fill_rawq()
          text = self.read_very_lazy()
          if not text and self.eof:
              raise EOFError
          return (-1, None, text)
  
  
  def test():
      """Test program for telnetlib.
  
      Usage: python telnetlib.py [-d] ... [host [port]]
  
      Default host is localhost; default port is 23.
  
      """
      debuglevel = 0
      while sys.argv[1:] and sys.argv[1] == '-d':
          debuglevel = debuglevel+1
          del sys.argv[1]
      host = 'localhost'
      if sys.argv[1:]:
          host = sys.argv[1]
      port = 0
      if sys.argv[2:]:
          portstr = sys.argv[2]
          try:
              port = int(portstr)
          except ValueError:
              port = socket.getservbyname(portstr, 'tcp')
      tn = Telnet()
      tn.set_debuglevel(debuglevel)
      tn.open(host, port, timeout=0.5)
      tn.interact()
      tn.close()
  
  if __name__ == '__main__':
      test()
  