web-based interface to linux or windows server

I'm volunteering to run a programming contest for my children's school and I want to build a web interface for children to submit their code - it is a competitive coding application, similar to robocode (http://ift.tt/KrJYKb) but a different thematic approach. I've already built a simulator that can handle between 1-4 contestants at a time, including a GUI based on freeglut, and it runs on Windows or Linux - but I'd like to create a web interface for submission/testing for the kids (submission for the final contest - testing for them to run their code in a demo environment for refinement). Ideally, it would be a file upload or text interface form that would remotely execute on my server and display the output in the web interface. The interface is low intensity 2D graphics, but does run for a few minutes (wall clock) of simulation time. No compilation of their code is necessary - the simulator is an interpreter. The school website uses wordpress, and I can use windows or linux for the server to run the simulator.

Is there any software already available to help me do this in a secure/robust manner? I have rudimentary PHP knowledge, but extensive non-web programming experience. I have tried to search for this on the forums, as I'm sure there are existing questions like this, but I'm having a hard time finding anything - maybe I have the wrong search terms.

thanks very much for any leads on this!