Meaning of some code in `timeout`

[Patrick Reader]

I was reading the source code for timeout 
(https://git.savannah.gnu.org/cgit/coreutils.git/tree/src/timeout.c#n589 
or 
https://github.com/coreutils/coreutils/blob/master/src/timeout.c#L589), 
and I saw this code:

> if (!timed_out && disable_core_dumps())
>   {
>     /* exit with the signal flag set.  */
>     signal(sig, SIG_DFL);
> unblock_signal(sig);
> raise(sig);
>   }

(starting on line 589, as of commit 
6c1723ec317efb787d70d40c55397d43846bcd38)

This is what I understand of this section: if the process was signalled, 
but not because it timed out, then raise the signal so that timeout's 
parent can observe that it exited due to a signal. We disable core dumps 
and check that that was successful to ensure that timeout won't dump its 
own core because of raising the signal.

Is this correct? I want to understand more about how timeout works, 
because I'm looking to implement a similar mechanism in one of my own 
projects and I want to be sure I know what the original code does before 
I go modifying it.

Thanks,

Patrick