KERNEL SYSTEM CALLS DEFINITIONS

[Sarita N]

Hello,
         I am a grad student at the university of nebraska lincoln.
I have to build a tool in C that would caputure the system calls and signals between a user application adn the operating system.  

I have started studying the Linux kernel.  Can I know how to go about it.  Where , in which Kernel file can I find the definitions of the various system calls - how have they been implemented in the kernel?

How do I go about the project?

Thanks and regards,
Sarita Navuluru.