Disabling the reuse timeout (-T 0) results in crashes

[ellie timoney]

Hi Jens,

Thanks for the patch.  This has also been reported as T227 by Ian
Batten: https://git.cyrus.foundation/T227

I'll get this fixed in git soon.

ellie

On Thu, Feb 18, 2016, at 11:13 PM, Jens Erat via Cyrus-devel wrote:
> Dear Cyrus developers,
> 
> `man imapd` explains `-T 0` should disable the reuse timeout:
> 
> > −T timeout
> > 
> > The number of seconds that the process will wait for a new connection before shutting down. Note that a value of 0 (zero) will disable the timeout. The default is 60.
> 
> But doing so results in crashes immediately after the first connection
> with an arithmetic exception. Digging deeper, the issue is rather
> obvious:
> 
>     reuse_timeout = reuse_timeout + (rand() % reuse_timeout);
> 
> This should not be executed for `reuse_timeout == 0`. I attached a small
> patch resolving the issue. `reuse_timeout = 0` results in disabled
> alarms, probably this border case was overlooked when the random timeout
> skew was added.
> 
> The patch is developed against Cyrus IMAP 2.5.7.
> 
> Regards from Lake Constance, Germany,
> Jens Erat
> 
> -- 
> Jens Erat
> Universität Konstanz
> Kommunikations-, Infomations-, Medienzentrum (KIM)
> Abteilung Basisdienste
> D-78457 Konstanz
> Mail: jens.erat at uni-konstanz.de
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