~azzar1/unity/add-show-desktop-key

#!/usr/bin/python

# usage:

#   python-console <port> <magic> [<working-dir>]

import cjson

import codeop

import cPickle

import cStringIO

import md5

import os

import Queue

import signal

import socket

import sys

import traceback

from threading import Thread

import common.chat

import common.util

# This version must be supported by both the local and remote code

PICKLEVERSION = 0

class Interrupt(Exception):

    def __init__(self):

        Exception.__init__(self, "Interrupted!")

class ExpiryTimer(object):

    def __init__(self, idle):

        self.idle = idle

        signal.signal(signal.SIGALRM, self.timeout)

    def ping(self):

        signal.alarm(self.idle)

    def start(self, time):

        signal.alarm(time)

    def stop(self):

        self.ping()

    def timeout(self, signum, frame):

        sys.exit(1)

class StdinFromWeb(object):

    def __init__(self, cmdQ, lineQ):

        self.cmdQ = cmdQ

        self.lineQ = lineQ

    def readline(self):

        self.cmdQ.put({"input":None})

        expiry.ping()

        action, params = self.lineQ.get()

        if action == 'chat':

            return params

        elif action == 'interrupt':

            raise Interrupt()

class StdoutToWeb(object):

    def __init__(self, cmdQ, lineQ):

        self.cmdQ = cmdQ

        self.lineQ = lineQ

        self.remainder = ''

    def _trim_incomplete_final(self, stuff):

        '''Trim an incomplete UTF-8 character from the end of a string.

           Returns (trimmed_string, count_of_trimmed_bytes).

        '''

        tokill = common.util.incomplete_utf8_sequence(stuff)

        if tokill == 0:

            return (stuff, tokill)

        else:

            return (stuff[:-tokill], tokill)

    def write(self, stuff):

        # print will only give a non-file a unicode or str. There's no way

        # to convince it to encode unicodes, so we have to do it ourselves.

        # Yay for file special-cases (fileobject.c, PyFile_WriteObject).

        # If somebody wants to write some other object to here, they do it

        # at their own peril.

        if isinstance(stuff, unicode):

            stuff = stuff.encode('utf-8')

        self.remainder = self.remainder + stuff

        # if there's less than 128 bytes, buffer

        if len(self.remainder) < 128:

            return

        # if there's lots, then send it in 1/2K blocks

        while len(self.remainder) > 512:

            # We send things as Unicode inside JSON, so we must only send

            # complete UTF-8 characters.

            (blk, count) = self._trim_incomplete_final(self.remainder[:512])

            self.cmdQ.put({"output":blk.decode('utf-8', 'replace')})

            expiry.ping()

            action, params = self.lineQ.get()

            self.remainder = self.remainder[512 - count:]

        # Finally, split the remainder up into lines, and ship all the

        # completed lines off to the server.

        lines = self.remainder.split("\n")

        self.remainder = lines[-1]

        del lines[-1]

        if len(lines) > 0:

            lines.append('')

            text = "\n".join(lines)

            self.cmdQ.put({"output":text.decode('utf-8', 'replace')})

            expiry.ping()

            action, params = self.lineQ.get()

            if action == 'interrupt':

                raise Interrupt()

    def flush(self):

        if len(self.remainder) > 0:

            (out, count) = self._trim_incomplete_final(self.remainder)

            self.cmdQ.put({"output":out.decode('utf-8', 'replace')})

            expiry.ping()

            action, params = self.lineQ.get()

            # Leave incomplete characters in the buffer.

            # Yes, this does mean that an incomplete character will be left

            # off the end, but we discussed this and it was deemed best.

            self.remainder = self.remainder[len(self.remainder)-count:]

            if action == 'interrupt':

                raise Interrupt()

class WebIO(object):

    """Provides a file like interface to the Web front end of the console.

    You may print text to the console using write(), flush any buffered output 

    using flush(), or request text from the console using readline()"""

    # FIXME: Clean up the whole stdin, stdout, stderr mess. We really need to 

    # be able to deal with the streams individually.

    def __init__(self, cmdQ, lineQ):

        self.cmdQ = cmdQ

        self.lineQ = lineQ

        self.stdin = StdinFromWeb(self.cmdQ, self.lineQ)

        self.stdout = StdoutToWeb(self.cmdQ, self.lineQ)

    def write(self, stuff):

        self.stdout.write(stuff)

    def flush(self):

        self.stdout.flush()

    def readline(self):

        self.stdout.flush()

        return self.stdin.readline()

class PythonRunner(Thread):

    def __init__(self, cmdQ, lineQ):

        self.cmdQ = cmdQ

        self.lineQ = lineQ

        self.webio = WebIO(self.cmdQ, self.lineQ)

        self.cc = codeop.CommandCompiler()

        Thread.__init__(self)

    def execCmd(self, cmd):

        try:

            # We don't expect a return value - 'single' symbol prints it.

            self.eval(cmd)

            self.curr_cmd = ''

            self.webio.flush()

            return({"okay": None})

        except:

            self.curr_cmd = ''

            self.webio.flush()

            tb = format_exc_start(start=2)

            return({"exc": ''.join(tb).decode('utf-8', 'replace')})

    def run(self):

        # Set up global space and partial command buffer

        self.globs = {}

        self.curr_cmd = ''

        # Set up I/O to use web interface

        sys.stdin = self.webio

        sys.stdout = self.webio

        sys.stderr = self.webio

        # Handlers for each action

        actions = {

            'chat': self.handle_chat,

            'block': self.handle_block,

            'globals': self.handle_globals,

            'call': self.handle_call,

            'execute': self.handle_execute,

            'setvars': self.handle_setvars,

            }

        # Run the processing loop

        while True:

            action, params = self.lineQ.get()

            try:

                response = actions[action](params)

            except Exception, e:

                response = {'error': repr(e)}

            finally:

                self.cmdQ.put(response)

    def handle_chat(self, params):

        # Set up the partial cmd buffer

        if self.curr_cmd == '':

            self.curr_cmd = params

        else:

            self.curr_cmd = self.curr_cmd + '\n' + params

        # Try to execute the buffer

        try:

            cmd = self.cc(self.curr_cmd, '<web session>')

            if cmd is None:

                # The command was incomplete, so send back a None, so the              

                # client can print a '...'

                return({"more":None})

            else:

                return(self.execCmd(cmd))

        except:

            # Clear any partial command

            self.curr_cmd = ''

            # Flush the output buffers

            sys.stderr.flush()

            sys.stdout.flush()

            # Return the exception

            tb = format_exc_start(start=3)

            return({"exc": ''.join(tb).decode('utf-8', 'replace')})

    def handle_block(self, params):

        # throw away any partial command.

        self.curr_cmd = ''

        # Try to execute a complete block of code

        try:

            cmd = compile(params, "<web session>", 'exec');

            return(self.execCmd(cmd))

        except:

            # Flush the output buffers

            sys.stderr.flush()

            sys.stdout.flush()

            # Return the exception

            tb = format_exc_start(start=1)

            return({"exc": ''.join(tb).decode('utf-8', 'replace')})

    def handle_globals(self, params):

        # Unpickle the new space (if provided)

        if isinstance(params, dict):

            self.globs = {}

            for g in params:

                try:

                    self.globs[g] = cPickle.loads(params[g])

                except:

                    pass

        # Return the current globals

        return({'globals': flatten(self.globs)})

    def handle_call(self, params):

        call = {}

        # throw away any partial command.

        self.curr_cmd = ''

        if isinstance(params, dict):

            try:

                # Expand parameters

                if isinstance(params['args'], list):

                    args = map(self.eval, params['args'])

                else:

                    args = []

                if isinstance(params['kwargs'], dict):

                    kwargs = {}

                    for kwarg in params['kwargs']:

                        kwargs[kwarg] = self.eval(

                            params['kwargs'][kwarg])

                else:

                    kwargs = {}

                # Run the fuction

                function = self.eval(params['function'])

                try:

                    call['result'] = function(*args, **kwargs)

                except Exception, e:

                    exception = {}

                    tb = format_exc_start(start=1)

                    exception['traceback'] = \

                        ''.join(tb).decode('utf-8', 'replace')

                    exception['except'] = cPickle.dumps(e,

                        PICKLEVERSION)

                    call['exception'] = exception

            except Exception, e:

                tb = format_exc_start(start=1)

                call = {"exc": ''.join(tb).decode('utf-8', 'replace')}

            # Flush the output buffers

            sys.stderr.flush()

            sys.stdout.flush()

            # Write out the inspection object

            return(call)

        else:

            return({'response': 'failure'})

    def handle_execute(self, params):

        # throw away any partial command.

        self.curr_cmd = ''

        # Like block but return a serialization of the state

        # throw away partial command

        response = {'okay': None}

        try:

            cmd = compile(params, "<web session>", 'exec');

            # We don't expect a return value - 'single' symbol prints it.

            self.eval(cmd)

        except Exception, e:

            response = {'exception': cPickle.dumps(e, PICKLEVERSION)}

        # Flush the output

        sys.stderr.flush()

        sys.stdout.flush()

        # Return the inspection object

        return(response)

    def handle_setvars(self, params):

        # Adds some variables to the global dictionary

        for var in params['set_vars']:

            try:

                self.globs[var] = self.eval(params['set_vars'][var])

            except Exception, e:

                tb = format_exc_start(start=1)

                return({"exc": ''.join(tb).decode('utf-8', 'replace')})

        return({'okay': None})

    def eval(self, source):

        """ Evaluates a string in the private global space """

        return eval(source, self.globs)

# The global 'magic' is the secret that the client and server share

# which is used to create and md5 digest to authenticate requests.

# It is assigned a real value at startup.

magic = ''

cmdQ = Queue.Queue()

lineQ = Queue.Queue()

interpThread = PythonRunner(cmdQ, lineQ)

terminate = None

# Default expiry time of 15 minutes

expiry = ExpiryTimer(15 * 60)

def initializer():

    interpThread.setDaemon(True)

    interpThread.start()

    signal.signal(signal.SIGXCPU, sig_handler)

    expiry.ping()

def sig_handler(signum, frame):

    """Handles response from signals"""

    global terminate

    if signum == signal.SIGXCPU:

        terminate = "CPU Time Limit Exceeded"

def dispatch_msg(msg):

    global terminate

    if msg['cmd'] == 'terminate':

        terminate = "User requested console be terminated"

    if terminate:

        raise common.chat.Terminate({"terminate":terminate})

    expiry.ping()

    lineQ.put((msg['cmd'],msg['text']))

    response = cmdQ.get()

    if terminate:

        raise common.chat.Terminate({"terminate":terminate})

    return response

def format_exc_start(start=0):

    etype, value, tb = sys.exc_info()

    tbbits = traceback.extract_tb(tb)[start:]

    list = ['Traceback (most recent call last):\n']

    list = list + traceback.format_list(tbbits)

    list = list + traceback.format_exception_only(etype, value)

    return ''.join(list)

# Takes an object and returns a flattened version suitable for JSON

def flatten(object):

    flat = {}

    for o in object:

        try:

            flat[o] = cPickle.dumps(object[o], PICKLEVERSION)

        except TypeError:

            try:

                o_type = type(object[o]).__name__

                o_name = object[o].__name__

                fake_o = common.util.FakeObject(o_type, o_name)

                flat[o] = cPickle.dumps(fake_o, PICKLEVERSION)

            except AttributeError:

                pass

    return flat

if __name__ == "__main__":

    port = int(sys.argv[1])

    magic = sys.argv[2]

    # Sanitise the Enviroment

    os.environ = {}

    os.environ['PATH'] = '/usr/local/bin:/usr/bin:/bin'

    if len(sys.argv) >= 4:

        # working_dir

        os.chdir(sys.argv[3])

        os.environ['HOME'] = sys.argv[3]

    # Make python's search path follow the cwd

    sys.path[0] = ''

    common.chat.start_server(port, magic, True, dispatch_msg, initializer)