door signal implementation

Hello everyone,I have a proximity sensor that detects whether the machine door is open or closed. I’d like to integrate this signal into my system so that:

1. If the door is open, the program automatically pauses.
2. If the door is closed, the program continues.
3. The program should not start if the door is open — it should only start once the door is fully closed.

What’s the best way to implement this behavior in my setup?

Hi,

i have something similar implemented in my machine. 
I have door closed signal, door locking signal (combined door sensor and locker). When TC is requested door is free of lock. When door is opened in manual mode when spindel is running. spindel stops. 

Attached you´ll find my hall (linux cnc 2.9.1). Search for door in the hal file (should be at the end). Hope you can recycle something..