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#!/usr/bin/env python

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# -*- coding: utf-8 -*-

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# This file is part of Beremiz, a Integrated Development Environment for

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# programming IEC 61131-3 automates supporting plcopen standard and CanFestival.

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#

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# Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD

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#

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# See COPYING file for copyrights details.

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#

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# This program is free software; you can redistribute it and/or

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# modify it under the terms of the GNU General Public License

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# as published by the Free Software Foundation; either version 2

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# of the License, or (at your option) any later version.

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#

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# This program is distributed in the hope that it will be useful,

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# but WITHOUT ANY WARRANTY; without even the implied warranty of

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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

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# GNU General Public License for more details.

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#

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# You should have received a copy of the GNU General Public License

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# along with this program; if not, write to the Free Software

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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

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from __future__ import absolute_import

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from __future__ import print_function

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import traceback

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from time import sleep

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import copy

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import socket

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import os.path

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import Pyro

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import Pyro.core

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import Pyro.util

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from Pyro.errors import PyroError

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import PSKManagement as PSK

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from connectors.PYRO.PSK_Adapter import setupPSKAdapter

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from runtime import PlcStatus

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def switch_pyro_adapter(use_ssl):

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    """

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    Reloads Pyro module with new settings.

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    This is workaround for Pyro, because it doesn't work with SSL wrapper.

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    """

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    # Pyro.config.PYRO_BROKEN_MSGWAITALL = use_ssl

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    reload(Pyro.protocol)

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    if use_ssl:

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        setupPSKAdapter()

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def PYRO_connector_factory(uri, confnodesroot):

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    """

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    This returns the connector to Pyro style PLCobject

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    """

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    confnodesroot.logger.write(_("PYRO connecting to URI : %s\n") % uri)

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    scheme, location = uri.split("://")

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    use_ssl = scheme == "PYROS"

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    switch_pyro_adapter(use_ssl)

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    if use_ssl:

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        schemename = "PYROLOCPSK"

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        url, ID = location.split('#')  # TODO fix exception when # not found

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        # load PSK from project

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        secpath = os.path.join(str(confnodesroot.ProjectPath), 'psk', ID+'.secret')

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        if not os.path.exists(secpath):

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            confnodesroot.logger.write_error(

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                'Error: Pre-Shared-Key Secret in %s is missing!\n' % secpath)

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            return None

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        secret = open(secpath).read().partition(':')[2].rstrip('\n\r')

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        Pyro.config.PYROPSK = (secret, ID)

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        # strip ID from URL, so that pyro can understand it.

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        location = url

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    else:

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        schemename = "PYROLOC"

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    # Try to get the proxy object

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    try:

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        RemotePLCObjectProxy = Pyro.core.getAttrProxyForURI(schemename + "://" + location + "/PLCObject")

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    except Exception as e:

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        confnodesroot.logger.write_error(

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            _("Connection to {loc} failed with exception {ex}\n").format(

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                loc=location, ex=str(e)))

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        return None

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    RemotePLCObjectProxy.adapter.setTimeout(60)

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    def PyroCatcher(func, default=None):

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        """

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        A function that catch a Pyro exceptions, write error to logger

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        and return default value when it happen

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        """

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        def catcher_func(*args, **kwargs):

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            try:

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                return func(*args, **kwargs)

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            except Pyro.errors.ConnectionClosedError as e:

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                confnodesroot._SetConnector(None)

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                confnodesroot.logger.write_error(_("Connection lost!\n"))

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            except Pyro.errors.ProtocolError as e:

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                confnodesroot.logger.write_error(_("Pyro exception: %s\n") % e)

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            except Exception as e:

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                # confnodesroot.logger.write_error(traceback.format_exc())

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                errmess = ''.join(Pyro.util.getPyroTraceback(e))

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                confnodesroot.logger.write_error(errmess + "\n")

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                print(errmess)

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                confnodesroot._SetConnector(None)

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            return default

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        return catcher_func

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    # Check connection is effective.

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    # lambda is for getattr of GetPLCstatus to happen inside catcher

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    IDPSK = PyroCatcher(RemotePLCObjectProxy.GetPLCID)()

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    if IDPSK is None:

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        confnodesroot.logger.write_warning(_("PLC did not provide identity and security infomation.\n"))

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    else:

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        ID, secret = IDPSK

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        PSK.UpdateID(confnodesroot.ProjectPath, ID, secret, uri)

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    _special_return_funcs = {

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        "StartPLC": False,

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        "GetTraceVariables": (PlcStatus.Broken, None),

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        "GetPLCstatus": (PlcStatus.Broken, None),

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        "RemoteExec": (-1, "RemoteExec script failed!")

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    }

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    class PyroProxyProxy(object):

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        """

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        A proxy proxy class to handle Beremiz Pyro interface specific behavior.

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        And to put Pyro exception catcher in between caller and Pyro proxy

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        """

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        def __getattr__(self, attrName):

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            member = self.__dict__.get(attrName, None)

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            if member is None:

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                def my_local_func(*args, **kwargs):

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                    return RemotePLCObjectProxy.__getattr__(attrName)(*args, **kwargs)

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                member = PyroCatcher(my_local_func, _special_return_funcs.get(attrName, None))

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                self.__dict__[attrName] = member

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            return member

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    return PyroProxyProxy