#!~/.wine/drive_c/Python25/python.exe
# -*- coding: utf-8 -*-

# Copyright (c) 2009-2014, Mario Vilas
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#     * Redistributions of source code must retain the above copyright notice,
#       this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice,this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * Neither the name of the copyright holder nor the names of its
#       contributors may be used to endorse or promote products derived from
#       this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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# $Id: 12_hook_function.py 1299 2013-12-20 09:30:55Z qvasimodo $

from winappdbg import Debug, EventHandler, System
from winappdbg.win32 import PVOID


# This function will be called when the hooked function is entered.
def wsprintf( event, ra, lpOut, lpFmt ):

    # Get the format string.
    process = event.get_process()
    lpFmt   = process.peek_string( lpFmt, fUnicode = True )

    # Get the vararg parameters.
    count      = lpFmt.replace( '%%', '%' ).count( '%' )
    thread     = event.get_thread()
    if process.get_bits() == 32:
        parameters = thread.read_stack_dwords( count, offset = 3 )
    else:
        parameters = thread.read_stack_qwords( count, offset = 3 )

    # Show a message to the user.
    showparams = ", ".join( [ hex(x) for x in parameters ] )
    print "wsprintf( %r, %s );" % ( lpFmt, showparams )


class MyEventHandler( EventHandler ):

    def load_dll( self, event ):

        # Get the new module object.
        module = event.get_module()

        # If it's user32...
        if module.match_name("user32.dll"):

            # Get the process ID.
            pid = event.get_pid()

            # Get the address of wsprintf.
            address = module.resolve( "wsprintfW" )

            # This is an approximated signature of the wsprintf function.
            # Pointers must be void so ctypes doesn't try to read from them.
            # Varargs are obviously not included.
            signature = ( PVOID, PVOID )

            # Hook the wsprintf function.
            event.debug.hook_function( pid, address, wsprintf, signature = signature)

            # Use stalk_function instead of hook_function
            # to be notified only the first time the function is called.
            #
            # event.debug.stalk_function( pid, address, wsprintf, signature = signature)


def simple_debugger( argv ):

    # Instance a Debug object, passing it the MyEventHandler instance.
    with Debug( MyEventHandler(), bKillOnExit = True ) as debug:

        # Start a new process for debugging.
        debug.execv( argv )

        # Wait for the debugee to finish.
        debug.loop()


# When invoked from the command line,
# the first argument is an executable file,
# and the remaining arguments are passed to the newly created process.
if __name__ == "__main__":
    import sys
    simple_debugger( sys.argv[1:] )