My first hook-Project

[Sunshine]

Hi all!

I just doing my first steps with madCodeHook and want to write a own small application. Inside this project I want to convert an existing and functioning Hook-DLL from C to Delphi. But there is an failure in my code, which I can't find. The target application which uses the hooked-DLL crashes imedeatly, whenn I start my own application. Here is the code of original hook-library

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void*	g_pDataBlockToMessage = NULL;

// ?DataBlockToMessage@@YAPAVMessage_t@@IPAX@Z
// is named DataBlockToMessage, returns a Message_t*,
// and takes an int and a void* as parameters.

//Message_t is actually a unknown class 
// But just to define a pointer on it,
// we don't need to know what it is.
typedef void Message_t;

Message_t* ( * pOriginalDataBlockToMessage )( int _Size, void* _pDataBlock );

Message_t* DataBlockToMessageHook( int _Size, void* _pDataBlock )
{
               /// Do something with the data.......  

	return pOriginalDataBlockToMessage( _Size, _pDataBlock );
}

In my own delphi main-application if have the following code:

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sucess:=InjectLibrary(ALL_SESSIONS or SYSTEM_PROCESSES, 'Hook.dll');

And in my hook.dll is the following code

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OriginalDataBlockToMessage : function (size: Integer; datablock: Pointer) :Pointer; cdecl;


function DataBlockToMessageHook(size : Integer; datablock: Pointer) :Pointer; stdcall;
begin
// Do something with the data..... (e.g. write to file)

result:=OriginalDataBlockToMessage(size,datablock);

end;

begin
HookAPI('path_to_dll','?DataBlockToMessage@@YAPAVMessage_t@@IPAX@Z',@DataBlockToMessageHook,@OriginalDataBlockToMessage);
end.

Thanks for any help in advance!

[madshi]

OriginalDataBlockToMessage : function (size: Integer; datablock: Pointer) :Pointer; cdecl;
function DataBlockToMessageHook(size : Integer; datablock: Pointer) :Pointer; stdcall;

Use either cdecl or stdcall, but mixing it like that is crazy!

[Sunshine]

Thx, you made my day! Now it works