Question

This would be easy with fork(), but I’ve got no MMU. I’ve heard that vfork() blocks the parent process until the child exits or executes exec(). How would I accomplish something like this?:

pid_t pid = vfork();

if (pid == -1) {
    // fail
    exit(-1);
}

if (pid == 0) {
    // child
    while(1) {
        // Do my daemon stuff
    }

    // Let's pretend it exits sometime
    exit();
} 

// Continue execution in parent without blocking.....

Answer 1

It seems there is no way to do this exactly as you have it here. exec or _exit have to get called for the parent to continue execution. Either put the daemon code into another executable and exec it, or use the child to spawn the original task. The second approach is the sneaky way, and is described here.