Yes, I see your point.

the only thing I could think where exec would be useful would be a small utility that popped up to tell you that config.ini has just been reread!
[kind of useless].


re: config.ini getting read late, Well in that case I guess you could make a call to read config.ini first before the player got a chance.

BTW: Does the kernel not start /bin/init itself? If so, how does it do it reliably is that a good place to look?
[if not, then who launches init if not the kernel?]

My comments above about becoming a process group leader might help you get started in the right direction.

The only thing you might have to watch out for is making sure that you start your process(es) after the kernel has started init - a lot of Unix things depend on init having a process id of 1 and any process that gets PID 1 that isn't init may get given more grief that it can handle later on.

If you find the source code to init you should be able to find the magic commands you need to do to get a userland app launched safely.
[and looking in the kernel code for what it does to run init and what it does BEFORE and after init is launches would make useful study too I think].