[sr-dev] Patches to get proper status code in daemonize mode

[Iñaki Baz Castillo]

2010/4/19 marius zbihlei <marius.zbihlei at 1and1.ro>:

> Indeed, main process is the process after the fork, and this is the
> process that writes to signal the parent. I see two possible pitfalls:

> 1. If the main process blocks, this will block the parent process also

This could be improved using select() with a timeout, right?


> 2. If the main process returns without writing the bytes, and there are
> still child processes left(tcp or udp worker children etc), then they will still
> have the writing part of the socket open (forked from the main process)and again
> the parent (master) process will keep blocking (didn't discovered a case where it might happen).

Then the workers should immediately close the pipe output fd after
being created, right?



> With a select it is possible to do a blocking read from some time. I
> strongly suggest more than 4-5 seconds, I think 30s should be a minimum.

ok, but IMHO 30 seconds is too much for a init script. However this is
a corner case.



>> Anyhow, I wonder if it would be enough. Note that in case the main
>> process gets blocked and the parent process exits with -1 (due to the
>> suggested timeout) the main process still remains running (even if
>> blocked). Perhaps the parent process should kill it and ensure it's
>> dead in case such timeout occurs?

> Good question.. We can kill all children from the main proces, but I am not
> sure that from the masetr process we can do this..

But if we just kill the main process from the parent process, then all
the workers and rest of children would be killed, right?
The problem would be if the main process gets "blocked" for some
reason, but I think that is a terrible case I've never seen.




Regards.


-- 
Iñaki Baz Castillo
<ibc at aliax.net>