Last active tty

Hello,

My name is Marcelo and I am a student in computer science facing a project that is getting difficult to implement.

In order to solve some of my problems I would like to get some information.

I would like to know if it is possible in Linux to know from user space which is the last active tty attached to an user i choose(the last tty which had some activity in it). I will be root or some other user which will have the proper privileges. I am willing to do any combination of system calls and tricks.

If it is not possible to do from user space then I would like to do it myself inside the kernel. I need to know where should I start reading to have the knowledge required to do the changes in the kernel (in my local copy of course).

I have some knowledge of the kernel and some little experience in programming inside the kernel (mainly i played with the scheduler and the virtual memory).

Thank you in advance,

Marcelo Taube