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Execute code in kernel mode.

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# 15  
Old 03-15-2011
Quote:
Originally Posted by lilezek
I don't need C++. Is just the language I always use. I don't know ASM and I didn't go deeper on C, so I prefer C++.
No, don't write your gettimeofday() in assembly, that'd be just silly. Smilie As is comparing C to assembly. Smilie

C isn't hard if you already know C++. All you'd be learning is the names of a few system calls.
# 16  
Old 03-15-2011
Quote:
Originally Posted by Corona688
It needs the LD_PRELOAD option though, which AFAIK is linux-specific.
Nah. The run-time linker for OpenBSD, NetBSD, FreeBSD, and SunOS/Solaris all support the LD_PRELOAD environment variable. If I'm not mistaken, AIX supports the functionality but the variable's name may be slightly different (LDR_PRELOAD perhaps?). Perhaps other systems as well.

Regards,
Alister
# 17  
Old 03-15-2011
Well. Now it is implemented and working well. The next part is to try to modify that function while Run-Time. Is it possible? I mean, not to launch the application with modified library, but change it while is running.

Thank you for replies. I did this part in the half time I thought it would cost me.
# 18  
Old 03-15-2011
Quote:
Originally Posted by lilezek
Well. Now it is implemented and working well. The next part is to try to modify that function while Run-Time. Is it possible? I mean, not to launch the application with modified library, but change it while is running.
No. But you could have your function check for things to decide whether it should act normally or not.

You could even have it call libc's own gettimeofday() by loading the symbol from libc with dlopen/dlsym and calling it with a function pointer... Again, libkeepalive's source tells you how to do that.
This User Gave Thanks to Corona688 For This Post:
lilezek
# 19  
Old 03-16-2011
Well. For an unknown reason (unknown for me) LD_PRELOAD is not working for some programs, just half of them:

For instance:

Code:
quake4
ERROR: ld.so: object 'speedhack.so' from LD_PRELOAD cannot be preloaded: ignored.

or:

Code:
tileracer
ERROR: ld.so: object 'speedhack.so' from LD_PRELOAD cannot be preloaded: ignored.

Any idea of what is happening? The library is placed on /usr/lib/ so I guess LD_PRELOAD can find it, because it works with my own test program for testing speedhack.
# 20  
Old 03-16-2011
What exactly have you set LD_PRELOAD to?
# 21  
Old 03-16-2011
Code:
$ echo $LD_PRELOAD
speedhack.so
$ ls /usr/lib/*hack.so
/usr/lib/openglhack.so  /usr/lib/speedhack.so
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