OS X Intercept Keyboard Events to Password Forms Elements

Question

I am currently creating a c program that counts all of the keys I press in a day and sorts the key types by amount, so I can tell which ones I press most often. It was more of a side project than anything else but I have become annoyed with the fact that my program doesn't seem to be able to intercept any input to password fields. I suppose this is a good thing, but I have been spending hours looking at documentation and trying to figure how to do this. I am not trying to create any sort of malicious software. Is there a way around this? My program is running as root. I am using the ApplicationServices framework and CGEventRef and the CGEventTapCreate funcion. Should I be using a different framework or struct? Also, is there a difference between kCGHIDEventTap, kCGSessionEventTap, and kCGAnnotatedSessionEventTap? I have tried using each of them and it does not seem to make a difference in my program.

I am running this on OS X 10.9

UPDATE Apparently I cannot capture keystrokes going to terminal either, which is where I spend most of my time on my laptop. This is a problem.

Answer 1

What you want is fairly complicated and requires a kernel extension. The interprocess communication is also not trivial. Take a look at logKext, specifically logKext.cpp. That project actually logs the keystrokes to an encrypted file. You should be able to pull everything you need from it.