VB Decompiler

MrUnleaded · Posted: Wed Dec 31, 2003 5:19 pm Post subject: gDL

Golem, if you dont mind me asking.... i was wondering if you had someway to represent COM in your gDL....you know i am trying to create something similar....and i was thinking about it and i am not sure if COM should be incorporated as its own tag or simply as some sort of redirect to an application that would parse COM specifically.

Does gDL on its own...define everything? COM, PCode[/Native]...or do you just hand off the start addresses to your Decompiler I think that is probably what i will end up doing....as i really dont think dead-listing tons of COM...would be effiecient....though it would make it extremely easy to modify....

What are your opinions on this?
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-MrU

golem · Often here Joined: 18 Nov 2002 Posts: 73

golems_Folly doesn't directly use gDL to document COM objects... That was basically sacrificed in the name of efficiency... an, at the time, saving time in the hot pursuit of providing COM support.

Keeping in mind that COM is decoded via a 'TYPELIB' resource in the Windows container, there is absolutely no reason why it couldn't be accomplished. It would certainly do away with some real painful limitations (and errors) of the freakin geniuses that wrote the COM interfaces...

Read: I really regret not having taken the time, as you are contemplating, to do it correctly.

All that would really involved to mimic gDL parsing would be to take the name of the container file (typically an OCX ), open it, start with the Dos_Header wind your way thru to the typelib resource and just start decoding... and create a parallel structure tree (+1 for each COM object used by the VB exectuable you are decompiling).

You might keep in mind that the very same resources that allow you to access COM will/should provide the basic documentation to support your effort.

Though gDL is active in determining the contents of the structures it finds/links, keep in mind it is more a structure documenter/explorer... It still requires coder interaction handle any new occurances or create new active fields. It is designed to bark when it encounters an unexpected result...

Think of gDL as a structures utility that reveals the skeleton, but it still needs supporting code to actually do something with it... for example the native/pcode flag though served up to the decompiler by gDL still needs code to actually do something with it.

As you can see, it's a pay me now or pay me later situation...

IMO, you are on the right track.

Carry on!
golem

MrUnleaded · Posted: Thu Jan 01, 2004 11:34 pm Post subject: i never thought of that...

Thanks for the info. Honestly i never gave a thought to processing the actual typelib of the files....mostly just figured i would get it from some external library some how like the TypeLibInfo class we have posted.

In parsing the typelib's it would only have to include the required components...this would be much better then having to have a huge list of COM objects and referencing a dead-list...

I think I have more to think about it and research before i procede....but thanks for the insight.
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-MrU