Cheat Engine

CodeReaver · Newbie cheater Reputation: 0 Joined: 19 Apr 2005 Posts: 24

I'd like to import the (ideally demangled) symbols from a linker address map such as this:

Dark Byte · Posted: Sat Jan 09, 2016 3:12 pm Post subject:

ce does load embedded debug symbols as well as .pdb files, but no .map files

You can add that yourself though by parsing the .map file manually and then add them to a custom SymbolList class object which you then register with the main symbol handler

CodeReaver · Newbie cheater Reputation: 0 Joined: 19 Apr 2005 Posts: 24

I know this is an old topic, but it's still something I could really do with getting working.

I figured out how to use the plugin system, but it doesn't look like there's any way to add user defined symbols that way. There is documentation online, but it's just spread over the web from what I can I've seen.

I can't tell how the way you describe it could be done from a plugin, but if the function to add user defined symbols was exposed in the SDK, the rest would be easy at this point. I have most of it ready to go. I'm not familiar with Delphi, so the C++ plugin is the easier route for me.

Sorry if I not explaining too well. It's late and I'm pretty tired.

Dark Byte · Posted: Fri Sep 02, 2016 5:38 am Post subject:

This lua code adds 2 symbols

CodeReaver · Newbie cheater Reputation: 0 Joined: 19 Apr 2005 Posts: 24

So, if I edited the example to have the following, would it then add those two symbols? Is there a way to get the extralist to stick around like refto_openmvandshowaddress does in the second example? It's easier for me to set up a loop with shorter strings that way instead of putting everything in one huge buffer.

Dark Byte · Posted: Fri Sep 02, 2016 7:19 am Post subject:

the first line : extralist=createSymbolList() makes of extralist a global.
That way it can be accessed from subsequent scripts without having to reregister/create

so all you have to do is create a loop of extralist.addsymbol() commands
(or in the example of openmvandshowaddress create your own function that takes some parameters, and then call that function using a reference and params only)

CodeReaver · Newbie cheater Reputation: 0 Joined: 19 Apr 2005 Posts: 24

OK, that sounds like it should do what I need. Are there any instructions on where to get the lua library from or whether I need to get a specific version in order to use it in Cheat Engine?

Is the symbol list object somewhere in CE's source code? It would be useful to see what functions it has available and in particular what that last parameter in the addSymbol function is for. It looks like the length of the function (calculated from the next entry in the file), however some of the symbol are likely to be variables rather than functions, so I won't know what to use in that case.

I found a code documentation page for CE, but it's hard to navigate without links to the parent/child folders. The git page works much better, but it's still hard to find the parts that relate to plugins and the parts that relate to the symbol list.

I really like the way the user defined symbols dialog works because it's easy to find everything and can instantly navigate to the addresses. Is there a way to get the symbols in that interface when I load them this way? I suppose I could recreate the interface in my own implementation if necessary, but I'd find it convenient if they already get added to the same list.

Dark Byte · Posted: Fri Sep 02, 2016 3:05 pm Post subject:

https://github.com/cheat-engine/cheat-engine/blob/master/Cheat%20Engine/bin/main.lua
Look for the symbollist class description

The symboklist you mean is accessed by registerSymbol

CodeReaver · Newbie cheater Reputation: 0 Joined: 19 Apr 2005 Posts: 24

That only looks like the class declaration, but not the implementation. It says what parameters the function takes, but not what it does with them.

I'm not trying to de difficult. I'm just not used to delphi or lua, so it's difficult to make deductions on what the next step would be.

I'm trying to see what the size and module are needed for, in order to deal with variables and not just the functions. Does CE have a list built in where I'll be able to see these symbols? I'm assuming they won't be treated as the user defined ones that I've seen in the menus.

EDIT: This is what I've ended up with:

Dark Byte · Posted: Sat Sep 03, 2016 9:13 am Post subject:

If you static link the library like the example then there is no need for a version check. If i ever change from lua 5.3 to something else (unlikely) the plugin won't be able to load as the dll can't be found.

You can move those blocks into a function

The gettop/settop is only needed in case of errors. Under normal usage the lua stack should remain the same

CodeReaver · Newbie cheater Reputation: 0 Joined: 19 Apr 2005 Posts: 24

OK, so I got my extra list working, but now I want to get a list working from which I can browse it and potentially add, edit or remove the entries and set the memory viewer to one if those locations.

Do you know how I'd go about extracting the data from the list? I'd probably need to know what functions are available in the symbol list class for getting the item by index or for iterating through the entries. If they are returned as a structure, I'd need to know that as well.

Although I looked in the file you referred me to earlier, it only appeared to have the name of the function, it's parameters and a description of what it does, and not the implementation. If that's somehow in one of the *.pas files, does the implementation use the same class name?

I could also use some examples of how to get function's return values out of lua and into C++.

One other thing I noticed is that when I used registerSymbol, the entries from the mapfile were added to the user defined symbols list like I wanted to happen from the beginning. Was it unsafe to do this, or did you think that wouldn't have met my requirements?

EDIT: So, I found a bit more data in main.lua. It says something like:

Dark Byte · Posted: Mon Sep 12, 2016 7:16 pm Post subject:

to get a return value, setup pcall so it sets up a return value.
when it returns without error, you can use lua_tointeger(luastate, -1) to get the return value. (or lua_tostring, or lua_tonumber, etc... And you can also return more than 1 result)

registerSymbol is fine. It just doesn't let you describe the size.

As for the symbol table, yes and no.

The symbol table in this case is just a lua table

CodeReaver · Newbie cheater Reputation: 0 Joined: 19 Apr 2005 Posts: 24

That's not quite what I meant. I'm not trying to treat the members of the Symbol object as array elements. I'm trying to access the table containing the Symbol objects as if it was as array. I want to pass in an index and get out the Symbol object at that position. If it doesn't work like that, I'd like to integrate through every Symbol object in the table instead.

**The above isn't so relevant after my recent findings**

OK, so I think I understand how the code works now.

Am I correct that these functions from luasymbollisthandler.pas are the only members of the symbol list class accessible from lua and that the actual symbol list itself that I'd be able to look up symbols for enumeration into a ListView is actually in symbollisthandler.pas as the TAvgLvlTree called AddressToString and StringToAddress?

Dark Byte · Posted: Thu Sep 15, 2016 10:56 am Post subject:

the symbolList object is an extension to the internal symbol handler. It just helps with address<->symbolname translation

and you're right, the class doesn't have an listSymbols method.

But, since you do add all the symbols yourself, you can just add a secondary list yourself

e.g:

CodeReaver · Newbie cheater Reputation: 0 Joined: 19 Apr 2005 Posts: 24

If I decided to implement my own list, then I might as well do that entirely from the plugin in C++ rather than trying to pass it through lua. The main benefit of going through lua was that the addresses I added appeared in both the disassembler window and the userdefined symbol list so that I could see what calls what and use the list in the menu to jump to them.

Anyway I've mostly got it working the way I want, except that CE isn't responding well to duplicates. I modified my lua function to check for a duplicate before passing it into the registerSymbol function. It seemed to work to begin with and then as my parser was able to find more symbols, it started complaining about symbols already in the list again.

Here's the function: