LUA's, and ToStrings, and Bears? Oh My!

[Harland]

Harro,

So I was working on my LUA wrapper last night and have hit a bump. Despite to extensive resources found via search, I am still having issues returning results with ToString.

I am executing all my Lua in WoW's main thread via an EndScene hook, so scope isn't the issue. It appears that I have not understood the concept of FrameScript_Execute [0x007F25C0] entirely, I believe a majority of people label this as DoString....

Anyways in dodgy pseudocode if I were to call in WoW's main thread:
Anyways lets assume I were to call the luaCommand UnitGUID("unit") where unit is some unit in my vicinity. Below is some dodgy psuedocode I would call the following. Please assume all the functions have been hooked appropriately with the offsets mentioned below. Also assume function typedefs have been correctly declared as Bobbysings WoWX Base.

//Offsets
//GetState            = 0x7F1160;
//GetTop              = 0x826D80;
//ToString            = 0x827290;
//FrameScript_Execute = 0x007F25C0;

FrameScript_Execute(luaCommand, 0, GetState());
int n = GetTop(GetState());
ToString(GetState(), n, 0);

What I would like to know is, should ToString() return a char * to the result returned by UnitGUID("unit")? Or is UnitGUID("unit") not pushing the GUID string to the luaStack?

Now I have seen Apoc post that he simply calls DoString -> GetTop -> ToLString. I must be missing something though.

One thing I notice is GetTop() always returns 0 for me (even after calling DoString numerous times), indicating the stack size has not increased at all.

I really do not want to use GetLocalizedText, Cypher has given many good reasons as to why. Although my Bot is not public or commercial (I only share it with close friends), I still do not wish to use the GetLocalizedText method.

ISXWoW's method of grabbing values elludes me right now, is it entirely necessary to register your own Lua Function in order to return results?

I'm open to any suggestions to get the DoString -> GetTop -> ToLString method working.

[Apoc]

I register a callback to do all my calls through.

Pass 0 for the lua_State param, so when it hits your callback you have a 'fresh' stack to work with.

[Harland]

Ah okay well that makes sense I'll go that route.

[Xarg0]

If you're going to register your own lua callback you'll have to do something about the isFunctionPtrInRange function, otherwise wow will crash when it tries to execute your lua function.
It's rather easy to trick the function, you coud for example just write a jmp to your lua callback into a codecave in wow and register it as your lua function, there are also serveral other ways to work around the functionptr check and I'd strongly suggest you to not patch the function, some parts are occupied by the warden, atleast they were occupied a year ago.

[Azzie2k8]

since apoc was so nice and linked me there here is something really useful

http://www.mmowned.com/forums/wow-me...ected-clr.html

as Xarg0 said you will need to patch the InvalidPointerFunction which is easy allthough robske told me how to do so (thanks )

[audible83]

Programming in Lua : contents

It has alot of info when you dont know how lua works...

[amadmonk]

A better solution is loadbuffer/pcall, but that takes a bit more RE'ing than just calling FramescriptExcecute.

[Apoc]

Don't patch the pointer check function, that's just stupid.

Just create a code cave somewhere in the .text section to jump to your func, and register your code cave's address instead.

[Harland]

Thanks for all the suggestions, most I have come across already during my browsing on the forum. I've finally got some moments to code now, so I'll see how I go.

[Harland]

Grrrr Shynd's Black Magic has spoiled me rotten....his BlackMagic Fasm wrapper made code caving easy. I have a problem, i'm trying to WriteProcessMemory to my codecave to jump to my lua function. Does anyone have some suggestions on how to convert an __asm block to bytes so that I may redirect flow to my lua function.

Perhaps some better terms to type into Google would be much appreciated :P

Edit: Forgot to mention i'm writing this in C++.

[kynox]

Grrrr Shynd's Black Magic has spoiled me rotten....his BlackMagic Fasm wrapper made code caving easy. I have a problem, i'm trying to WriteProcessMemory to my codecave to jump to my lua function. Does anyone have some suggestions on how to convert an __asm block to bytes so that I may redirect flow to my lua function.

Perhaps some better terms to type into Google would be much appreciated :P

Edit: Forgot to mention i'm writing this in C++.

asmjit - Project Hosting on Google Code

[Harland]

Cheers Kynox, I'm so happy I could kiss your sister right now. It's ashame Cypher gave her herpes though.

[kynox]

Cheers Kynox, I'm so happy I could kiss your sister right now. It's ashame Cypher gave her herpes though.

Hilarious. Really.

[Cypher]

Cheers Kynox, I'm so happy I could kiss your sister right now. It's ashame Cypher gave her herpes though.

Kynox's mum told me she was clean. She lied.