Timing and limiting threads in Linux with pascal

[salgau_catalin]

I'm tired of searching and I'm going to ask people.
I´m trying to write a problem evaluation program.
I´m working under Linux.
What I need is a way to start another file, time it with very high
accuracy(would be nice if it could report CPU time and user time),
check for screen output and input(and eventually pass data to it and
read the output, but this is not a requirement. normally they should
read and write to files.) and kill it if it runs for longer then a
specified time(usually 0.1 seconds) or if it passes a specified
memory space(usually 64 MB).
I´m not a Linux pro, so I´d appreciate it if you could walk me
through memory management on that last one. I´m figuring I should
set a maximum memory usage quota for the user, but I´m not sure how and what would happen/how I should detect it when it happens.
Whatever is going on with the run program, the most important this
is for it not to crash the evaluator.
The machine will be dedicated so I can create whatever user it needs
and allow it whatever priviledges it requires, but to tell me what
those are.
Hope someone can help me.