It has certainly been a while since the last update, mostly because I’ve been rather busy with university. But I’m going to try to catch up a bit and talk about what I’ve been up to.
In the last few months I’ve been doing a bunch of reverse engineering and bot-writing for EVE Online, looking at ways to make money with it. There are a few fundamental differences in the way botting works in these two games: In World of Warcraft the way to make money is through mineral nodes like Saronite or Titanium Ore. A bot that needs to farm these is relatively simple, all it needs to do is fly in circles and pick up nodes, eventually fighting off attackers. To get the equivalent of a few hundred USD it is enough to run such a bot for maybe 6 hours a day.
In EVE Online the comparable easy way is mining ores, too, but the real money value yield is much lower per hour spent botting, so it is required to run a bot pretty much all day. There are better methods that yield more money though, for example mission running, but due to the nature of the game, in order to successfully complete the well earning missions it is required to spend several hundred days training skills. Since I did not care about EVE previously and do not have a suitable character, this is pretty much impossible at the moment.
However, there is one important advantage to EVE: There is only one server. In World of Warcraft you get about half a thousand servers, which makes it incredibly difficult to sell the in-game currency. In EVE the only limit is how much you can make; if you don’t want to sell it yourself, there are several websites that bring you into contact with a potential buyer.
That, and the possibility of improvements (and EVE looked kinda interesting as a game too) in the form of missions made me look into botting in EVE. It turned out that is incredibly easy there, compared to World of Warcraft: Since the game is entirely written in Python and there is an old decompiled source code dump available on the Internet, it was very easy to get started there.
To get access to EVE’s Python interpreter I injected a DLL that loads or retrieves a handle to the python25.dll module of the specific process and uses GetProcAddress to retrieve function addresses for any Python function I ended up needing. It’s not really required to do retrieve all these addresses manually and specify required function prototypes for them though, since one could also link to the DLL at compile time and have the dynamic linker retrieve the addresses, then it’s possible to just use the Python functions without any problems, since EVE’s Python 2.5 version and the one from the website probably aren’t different (?).
Since calling Python functions from another thread ended up being rather problematic for me, because the normal Global Interpreter Lock (GIL) functionality did not work and a hack that ended up working was a bit too messy for my tastes, I just ended up hooking (with MS Detours for example) the Python function`PyStackless_CallMethod_Main, which EVE’s ExeFile.exe calls to set off the Python part of the game.
In trying to interact with EVE’s python base though I encountered a problem: If I just executed my Python code with execfile() or eval(), my code ended up being executed in a different execution frame (I think) and thus had a different __builtin__ (Python’s “main” module where all the .. built-in commands or variables are. The solution turned for me ended up importing the “stackless” module and just queuing a new tasklet to be executed with stackless.tasklet(execfile)(“myfile.py”). It then ended up being executed by the main frame with the correct __builtin__.
At that point I ended up hooking EVE’s Startup function that was located somewhere in a autoexec_client_main module (It becomes pretty obvious from the source) and was able to properly interact with EVE’s GUI functions and so on afterwards, but that’s mostly just toying around and unnecessary. It takes a while to dig through the EVE source and figure out how it works, but it’s necessary to do anything, and thanks to the dudes who properly decompiled the bytecode ages ago (decompyle doesn’t work with Python 2.5, and UnPyc, an attempt to build a decompiler for Pythons up to version 2.6 is not finished and apparently abandoned. Aside from that there’s just commercial decompiling companies, and they probably won’t help with the EVE code ;)).
But to get a usable interpretation of EVE’s bytecode (that’s contained in the script/compiled.code file and lib/*.ccp archives (they really are just ZIP archives) and easily extractable, but I’ll go into that in another post) it’s really enough to just run Python’s included disassembler in the “dis” module over the code objects. Some dude called Ricky26 who apparently worked on a custom EVE server has already done a bunch of work on that, he also wrote a script that deals with the extracting and disassembling of the compiled code. But again, I’ll go into that in another post, this one is already getting too long.