How to create a System Call to extract data from a process in progress? [closed]

I need to make a System Call that receives a PID as a parameter and returns the number of bytes that this process read from the standard input, from the disk, and how many bytes it wrote to the USB port. As I'm a beginner in programming for Linux, I'm kind of lost, but by doing a lot of research I discovered System Call "ptrace" and I think it can help a lot. I'm using the Ubuntu Kernel 4.3 environment. If anyone can give a light I thank you very much.