exec code with timeout?

[JCM]

"OKB (not okblacke)" <BrenBarn at aol.com> wrote:
>     	I am fiddling around with a Python-based MUD which allows users to 
> code MUD objects in Python.  This code is executed from within the 
> server code with "exec".  However, sometimes errors in user code can 
> result in infinite loops, which cause the MUD to hang.  I am wondering 
> if there is a way to put a timeout on the exec, so that it returns 
> control to the main program if the user code doesn't return within a 
> certain amount of time.

We've done exactly this for our own MUD project :)

The way we got around the infinite loop problem was to have the main
Python thread be the one that runs all unknown MUD-code.  You can use
signals (on unix) to raise an exception in the main thread.  I don't
remember offhand what function we used--maybe os.kill?