# -*- coding: utf-8 -*-
# $Id: loopback.py 96407 2022-08-22 17:43:14Z vboxsync $

"""
VirtualBox Validation Kit - Serial loopback module.
"""

__copyright__ = \
"""
Copyright (C) 2018-2022 Oracle and/or its affiliates.

This file is part of VirtualBox base platform packages, as
available from https://www.virtualbox.org.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation, in version 3 of the
License.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, see <https://www.gnu.org/licenses>.

The contents of this file may alternatively be used under the terms
of the Common Development and Distribution License Version 1.0
(CDDL), a copy of it is provided in the "COPYING.CDDL" file included
in the VirtualBox distribution, in which case the provisions of the
CDDL are applicable instead of those of the GPL.

You may elect to license modified versions of this file under the
terms and conditions of either the GPL or the CDDL or both.

SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
"""
__version__ = "$Revision: 96407 $"

# Standard Python imports.
#import os;
import socket;
import threading;


g_ksLoopbackTcpServ         = 'TcpServ';
g_ksLoopbackTcpClient       = 'TcpClient';
g_ksLoopbackNamedPipeServ   = 'NamedPipeServ';
g_ksLoopbackNamedPipeClient = 'NamedPipeClient';

class SerialLoopbackTcpServ(object):
    """
    Handler for a server TCP style connection.
    """
    def __init__(self, sLocation, iTimeout):
        sHost, sPort = sLocation.split(':');
        self.oConn = None;
        self.oSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM);
        self.oSock.settimeout(iTimeout);
        self.oSock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1);
        self.oSock.bind((sHost, int(sPort)));
        self.oSock.listen(1);
        self.iTimeout = iTimeout;

    def __del__(self):
        if self.oConn is not None:
            self.oConn.close();
        if self.oSock is not None:
            self.oSock.close();
            self.oSock = None;

    def shutdown(self):
        if self.oConn is not None:
            self.oConn.close();
            self.oConn = None;
        self.oSock.close();
        self.oSock = None;

    def pumpIo(self):
        """
        Main I/O pumping routine.
        """
        try:
            if self.oConn is None:
                oConn, _ = self.oSock.accept();
                self.oConn = oConn;
            else:
                abData = self.oConn.recv(1024); # pylint: disable=no-member
                if abData is not None:
                    self.oConn.send(abData);    # pylint: disable=no-member
        except:
            pass;

class SerialLoopbackTcpClient(object):
    """
    Handler for a client TCP style connection.
    """
    def __init__(self, sLocation, iTimeout):
        sHost, sPort = sLocation.split(':');
        self.oConn = socket.socket(socket.AF_INET, socket.SOCK_STREAM);
        self.oConn.connect((sHost, int(sPort)));
        self.oConn.settimeout(iTimeout);
        self.iTimeout = iTimeout;

    def __del__(self):
        if self.oConn is not None:
            self.oConn.close();

    def shutdown(self):
        if self.oConn is not None:
            self.oConn.close();
            self.oConn = None;

    def pumpIo(self):
        """
        Main I/O pumping routine.
        """
        try:
            abData = self.oConn.recv(1024);
            if abData is not None:
                self.oConn.send(abData);
        except:
            pass;

class SerialLoopbackNamedPipeServ(object):
    """
    Handler for a named pipe server style connection.
    """
    def __init__(self, sLocation, iTimeout):
        self.oConn = None;
        self.oSock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM); # pylint: disable=no-member
        self.oSock.settimeout(iTimeout);
        self.oSock.bind(sLocation);
        self.oSock.listen(1);
        self.iTimeout = iTimeout;

    def __del__(self):
        if self.oConn is not None:
            self.oConn.close();
        if self.oSock is not None:
            self.oSock.close();
            self.oSock = None;

    def shutdown(self):
        if self.oConn is not None:
            self.oConn.close();
            self.oConn = None;
        self.oSock.close();
        self.oSock = None;

    def pumpIo(self):
        """
        Main I/O pumping routine.
        """
        try:
            if self.oConn is None:
                oConn, _ = self.oSock.accept();
                self.oConn = oConn;
            else:
                abData = self.oConn.recv(1024); # pylint: disable=no-member
                if abData is not None:
                    self.oConn.send(abData);    # pylint: disable=no-member
        except:
            pass;

class SerialLoopbackNamedPipeClient(object):
    """
    Handler for a named pipe client style connection.
    """
    def __init__(self, sLocation, iTimeout):
        self.oConn = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM); # pylint: disable=no-member
        self.oConn.connect(sLocation);
        self.oConn.settimeout(iTimeout);
        self.iTimeout = iTimeout;

    def __del__(self):
        if self.oConn is not None:
            self.oConn.close();

    def shutdown(self):
        if self.oConn is not None:
            self.oConn.close();
            self.oConn = None;

    def pumpIo(self):
        """
        Main I/O pumping routine.
        """
        try:
            abData = self.oConn.recv(1024);
            if abData is not None:
                self.oConn.send(abData);
        except:
            pass;

class SerialLoopback(object):
    """
    Serial port loopback module working with TCP and named pipes.
    """

    def __init__(self, sType, sLocation):
        self.fShutdown = False;
        self.sType     = sType;
        self.sLocation = sLocation;
        self.oLock     = threading.Lock();
        self.oThread   = threading.Thread(target=self.threadWorker, args=(), name=('SerLoopback'));

        if sType == g_ksLoopbackTcpServ:
            self.oIoPumper = SerialLoopbackTcpServ(sLocation, 0.5);
            self.oThread.start();
        elif sType == g_ksLoopbackNamedPipeServ:
            self.oIoPumper = SerialLoopbackNamedPipeServ(sLocation, 0.5); # pylint: disable=redefined-variable-type
            self.oThread.start();

    def connect(self):
        """
        Connects to the server for a client type version.
        """
        fRc = True;
        try:
            if self.sType == g_ksLoopbackTcpClient:
                self.oIoPumper = SerialLoopbackTcpClient(self.sLocation, 0.5);
            elif self.sType == g_ksLoopbackNamedPipeClient:
                self.oIoPumper = SerialLoopbackNamedPipeClient(self.sLocation, 0.5); # pylint: disable=redefined-variable-type
        except:
            fRc = False;
        else:
            self.oThread.start();
        return fRc;

    def shutdown(self):
        """
        Shutdown any connection and wait for it to become idle.
        """
        with self.oLock:
            self.fShutdown = True;
        self.oIoPumper.shutdown();

    def isShutdown(self):
        """
        Returns whether the I/O pumping thread should shut down.
        """
        with self.oLock:
            fShutdown = self.fShutdown;

        return fShutdown;

    def threadWorker(self):
        """
        The threaded worker.
        """
        while not self.isShutdown():
            self.oIoPumper.pumpIo();