How to code new user defined system calls for linux

I M A STUDENT OF MASTER OF COMPUTER APPLICATION. I AM DOING AN OPERATING SYSTEM PROJECT ON "USER-DEFINED SYSTEM CALL ON LINUX". I KNOW THE KNOW HOWS OF LINUX BUT AM NEW TO THE KERNAL LEVEL PROGRAMMING. CAN ANY ONE SUGGEST HOW SHOULD I BEGIN OR IS THERE ANY PRECODED PROJECT SIMILAR TO MINE SO THAT I CAN GET HELP FROM THAT ONE.

thanks shashank, point noted sir, from now on i wont be using caps ne more. and sir, can u guide me how to start with the project. i can do the coding part but i donno know where and what to start with.

There are two parts to this problem: 1. The kernel side of the call. 2. The API that invokes it. First, get the kernel source for your system and look at some of the calls that might do something like what you want. Next, look at the library source code that provides the API to those calls for user-written programs. Finally, you need to find out how you link your call into the kernel. With current kernels you can either link your call directly into the kernel itself, or you can build a dynamically loadable kernel module that can be linked into the kernel at boot time. The techniques for each of these approaches are quite different. I'm sorry that I don't have enough Linux kernel experience to advise you further than this.

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