#!/usr/bin/python
#
# Copyright 2010 Red Hat, Inc. and/or its affiliates.
#
# Licensed to you under the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.  See the files README and
# LICENSE_GPL_v2 which accompany this distribution.
#

import os, socket, struct, platform, sys

class Message:
    PowerUp             = 1
    PowerDown           = 2
    Heartbeat           = 3
    MachineName         = 4
    GuestOs             = 5
    IpAddresses         = 6
    LastSessionMessage  = 7
    UserInfo            = 8
    NewApp              = 9
    FlushApps           = 10
    ClientIp            = 11 # Obsolete
    SessionLock         = 12
    SessionUnlock       = 13
    SessionLogoff       = 14
    SessionLogon        = 15
    AgentCommand        = 16 # Obsolete
    AgentUninstalled    = 17 # A place holder. message is send from the uninstaller.
    SessionStartup      = 18
    SessionShutdown     = 19

READ_HEADER         = "III"
READ_HEADER_LEN     = struct.calcsize(READ_HEADER)
WRITE_HEADER        = "IIII"
WRITE_HEADER_LEN    = struct.calcsize(WRITE_HEADER)

class VirtIoChannel:

    # Python on Windows 7 return 'Microsoft' rather than 'Windows' as documented.
    is_windows = (platform.system() == 'Windows') or (platform.system() == 'Microsoft')

    def __init__(self, vport_name):
        if self.is_windows:
            from windows_support import WinBufferedReadFile
            self._vport = WinBufferedReadFile(vport_name)
        else:
            self._vport = os.open(vport_name, os.O_RDWR)

    def read(self):
        size = self._read_header()
        if self.is_windows:
            rest = self._vport.read(size)
        else:
            rest = os.read(self._vport, size)
        # TODO: concat message? handle NULL terminated string?
        cmd = struct.unpack("%ds" % len(rest), rest)[0]
        return cmd

    def write(self, message, arg = ''):
        if type(message) != int:
            raise TypeError("1nd arg must be a known message type.")
        if type(arg) != str:
            raise TypeError("2nd arg must be a string.")
        stream = self._pack_message(message, arg)
        if self.is_windows:
            self._vport.write(stream)
        else:
            os.write(self._vport, stream)
    
    def _read_header(self):
        if self.is_windows:
            hdr = self._vport.read(READ_HEADER_LEN)
            print hdr
        else:
            hdr = os.read(self._vport, (READ_HEADER_LEN))        
        if hdr == '':
            return 0
        return socket.ntohl(struct.unpack(READ_HEADER, hdr)[2]) - READ_HEADER_LEN
    
    def _pack_message(self, message, arg):
        size = WRITE_HEADER_LEN + len(arg)
        stream = struct.pack(WRITE_HEADER + "%ds" % len(arg),
            socket.htonl(1), socket.htonl(3), socket.htonl(size), socket.htonl(message), arg)
        return stream


def test(path):
    print 'the scripts need to use device name ,eg -device virtserialport,chardev=xxx,name=mikecao,id=port2,here pls input mikecao\n'
    print 'If your commandline forgot to add name for virtserialport ,you can not use this script ,pls add one the nre-open it \n'
  
#  path = raw_input("com.redhat.rhevm.vdsm\n")
    if (platform.system() == 'Windows') or (platform.system() == 'Microsoft'):
        vport_name = '\\\\.\\Global\\' + path
        print 'pull path is ' + vport_name ;
    else:
        vport_name = '/dev/virtio-ports/' + path
    vio = VirtIoChannel(vport_name)   
    print vio.read()

if __name__ == "__main__":
    print '*******************************************************************************************************************'
    print 'Note: This scripts only used for transferring file from guest to host,you need to execute #Python Serial-gues-to-host.py on the host first '
    print ' '
    print 'When you use this scripts ,pls create b.txt and write sth in it and put it in the same directory as the VirtIOChannel.py '
    print ' ' 
    print 'Anything concern ,pls contract with Mike Cao <bcao@redhat.com>'
    print '*******************************************************************************************************************'

    test(sys.argv[1])