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General Programming / [ASM/C++] Function redirection
« on: September 26, 2005, 04:51:29 pm »
(gcc, nasm, Linux 2.6)
I'm in need of hijacking a non-virtual function in the Half Life 2 SDK. It is non-virtual, because obviously valve doesn't want to give developers access to it.
I've written a server plugin for the hl2 daemon, and this library contains the function which I want to use as a replacement for a standard function in one of the hl2 daemon shared libraries.
This is what I'm doing so far:
My plugin is loaded into the daemon's address space. The plugin finds the address of the function I want to replace using dlopen and dlsym.
The plugin creates a function pointer to the function which I want to use as a replacement.
How would I proceed in redirecting all calls to my function instead of the standard one? I'm not too keen on editing the .GOT or .PLT. I need the stack frame from the original function to stay in tact, because I will be using the parameters.
Any suggestions, with maybe some sample code?
Thanks in advance.
I'm in need of hijacking a non-virtual function in the Half Life 2 SDK. It is non-virtual, because obviously valve doesn't want to give developers access to it.
I've written a server plugin for the hl2 daemon, and this library contains the function which I want to use as a replacement for a standard function in one of the hl2 daemon shared libraries.
This is what I'm doing so far:
My plugin is loaded into the daemon's address space. The plugin finds the address of the function I want to replace using dlopen and dlsym.
The plugin creates a function pointer to the function which I want to use as a replacement.
How would I proceed in redirecting all calls to my function instead of the standard one? I'm not too keen on editing the .GOT or .PLT. I need the stack frame from the original function to stay in tact, because I will be using the parameters.
Any suggestions, with maybe some sample code?
Thanks in advance.