[CentOS] Init checking for processes that are configured to "respawn"

Tue Jul 7 11:44:38 UTC 2009
Michael Kralka <michael.kralka at gmail.com>

On 2009-07-07, at 6:17 AM, "Dirk H. Schulz"  
<dirk.schulz at kinzesberg.de> wrote:

> Hi folks,
> I have a sophisticated question for which I can't find any hints on  
> the
> web:
> If you configure init (via /etc/inittab) to respawn processes (like  
> the
> getty processes) when they exit - how often does init check for the
> existence of such a process? Does it check actively at all or does it
> rely on some kind of inter process communication?

I'd imagine it uses wait (man 2 wait) and/or waits for a SIGCHLD to be  
sent. The latter sent to it whenever a child process exits.

In either case, the spawned process does not need to be aware of how  
knit works under the hood.