How to debug to find memory locations??

[Baaleos]

Ok, I have downloaded IDA Debugger Pro freeware edition.


Im trying to make heads n tails of it, and try to make my own simple plugins for nwnx.

I've set myself an easy task.
Make a plugin which will let me change the Servername from within the game.


So, I have opened up nwserver.exe in IDA, and it does alot of decompiling etc, and stuff, and leaves me there.

The top wee dropdown, has some settings.
When I set it to Name, and then browse through the accompaning dropdown, I am able to find aServername

Ok, So, I am assuming this is the name of a function or Subroutine, or possibly a value. Since the nwnserver doesnt seem to be actually running at the moment, I would hazard a guess that it is a placeholder possibly for the value that gets assigned for the server name.

407E4E - Appears to be the loc of the subroutine, while
407470+98f - This seems to be the name of the subroutine, IDA being helpful even tells me that it requires one parameter.

I will try adding an execution breakpoint round here, and see if when I change the servers name, if the execution count increases...

[Baaleos]

Ok... Ive got an understanding of how to use c++ to write to memory locations etc, but my main crux at the minute, is how do you guys find the memory locations etc.

How on earth did you find the PlayerList memory location,
or the ChatHook code structure (that being said.... when I do a hex search for the Chat Hook hex string, it never finds it... yet the plugin works...)

Im sure I could develop something.... anything, regardless of how lame it is, if I but had a clue how to locate these memory locations etc.

Gonna have another go, this time, with cheatengine helping me.
Will use it to scan for memory location values, and see if any of them are static, or have pointers.

[Baaleos]

I've managed to locate the subroutine which handles the 'maxclient' number.

Its sub_429110 and it sets the maxclient value to be equal to arg[0] - the first and only argument passed in.

Now... how does one turn this into useful information.

Im guessing that the sub_429110 is a static location. Hmmmm
Yeah... I know... set out to get server name, but then settled on server player amount.