linux-kernel - Re: SIGHUP on connect

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Date:   Thu, 29 Oct 2020 15:54:47 +0100
From:   "Michael J. Baars" <mjbaars1977.linux-kernel@...erfiber.eu>
To:     Bernd Petrovitsch <bernd@...rovitsch.priv.at>,
        linux-kernel@...r.kernel.org
Subject: Re: SIGHUP on connect

On Mon, 2020-10-26 at 17:12 +0000, Bernd Petrovitsch wrote:
> Hi all!
> 
> On 25/10/2020 16:11, Michael J. Baars wrote:
> [...]
> > I've been writing a simple client and server for cluster computing this weekend. At first everything appeared to work just fine, but soon enough I found
> > some
> > inexplicable bind errors. I've tried to make sure that the client closes it's sockets before the server closes it's sockets, to prevent linger, but trying
> > did
> 
> Which were exactly?
> English/original text pls ...
> 
> And The close() (and shutdown() syscalls, respectively) don't avoid
> the FIN_WAIT2 timeout on a closed socket.
> Just set the SO_REUSEADDR socket option on the listening socket.
> 
> > not help. Now I think I found the problem.
> 
> Then solve it.
> 
> > Please do have a look at the code. It looks like the SIGHUP is sent to the server not on close or exit, but on the connect instead.
> 
> Too lazy to save and uncompress the file ...
> 
> MfG,
> 	Bernd

And I think this was sort of part of the question:

We have on sock[0] serverside 1 SIGHUP on the connect
We have on sock[1] serverside about 7 SIGHUPs on the close

Why not sent these 6 or 7 SIGHUPs on sock[0], such that the SIGHUP handler has to be installed only once?

Regards,
Mischa.