tcpterm

#!/usr/bin/env python
# TCP Terminal Utility - Andrew Klofas <andrew.klofas@gmail.com> - Dec 2008

import argparse, socket, sys, tty, termios, signal, errno, os
from threading import Thread, Event


# Quit code
cmdQUIT = (0x18, "Ctrl-x")
returnSTATUS = 0


# Parse args
p = argparse.ArgumentParser(description='Open a terminal over a raw tcp socket')
p.add_argument('--cmd', '-c', action='append', default=[], help='Commands to be executed at the beginning of the session')
p.add_argument('host', help='Specifies a host to contact over the network.')
p.add_argument('port', type=int, help='Specifies a port number to contact.')
a = p.parse_args()


# Connect to server
try:
	s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
	s.connect((a.host, a.port))

	# Write commands list first
	for c in a.cmd:
		s.sendall(c + '\n')

except socket.error as e:
	sys.stderr.write("%s.\n" % (os.strerror(e.errno)))
	sys.exit(e.errno)
	

# Read from socket and dump to stdout
def sock2stdout(qe):
	while True:
		data = s.recv(1024)
		if not data: break
		sys.stdout.write(data)
		sys.stdout.flush()

	# Flag the quit event
	qe.set()


# Read from stdin and dump to socket
def stdin2sock(qe):
	while True:
		try:
			c = sys.stdin.read(1)
			if ord(c) == cmdQUIT[0]: break
			s.send(c)

		except IOError as e:
			# Ignore if errno is one of these
			if e.errno in [errno.EINTR]: continue
			# Cleanly exit if errno is one of these
			if e.errno in [errno.EPIPE, errno.EBADF]: break

			sys.stderr.write("%s.\n" % (os.strerror(e.errno)))
			returnSTATUS = e.errno
			break

	# Flag the quit event
	qe.set()


eventQUIT = Event()
stdoutTHREAD = Thread(target=sock2stdout, args=(eventQUIT,))
stdinTHREAD = Thread(target=stdin2sock, args=(eventQUIT,))


# Forward terminal control signals
signal.signal(signal.SIGINT, lambda _1, _2: s.send(chr(0x03)))
signal.signal(signal.SIGTSTP, lambda _1, _2: s.send(chr(0x1A)))
signal.signal(signal.SIGQUIT, lambda _1, _2: s.send(chr(0x1C)))


# Print header
sys.stdout.write("> Welcome to TCPTerm. Press %s to quit.\n" % (cmdQUIT[1]))


# Get 1 byte at a time from stdin
old = termios.tcgetattr(sys.stdin)
try:
	tty.setcbreak(sys.stdin.fileno())

	# Start the threads
	stdoutTHREAD.start()
	stdinTHREAD.start()

	# Wait for quit event
	eventQUIT.wait()

finally:
	termios.tcsetattr(sys.stdin, termios.TCSADRAIN, old)

# Close down
s.close()
sys.exit(returnSTATUS)