Re: [PATCH] Fix multiple minor tzset glitches [BZ #24004]

[Yann Droneaud <ydroneaud at opteya dot com>]

Hi,

Le jeudi 14 mars 2019 à 19:48 +0100, Florian Weimer a écrit :
> * Paul Eggert:
> > On 3/14/19 7:10 AM, Florian Weimer wrote:
> > > * Paul Eggert:
> > > 
> > > > Yes, and it would be good to add a way to control polling of /etc files,
> > > > and whatever method is used to control polling of /etc/nsswitch.conf
> > > > etc. could also be used to control polling of /etc/localtime.
> > > I think this should be a configuration file.  We can use a shared
> > > mapping (or use /etc/ld.so.cache) to make up-to-date checks really,
> > > really cheap.  But I think we should apply this mechanism only to files
> > > where the system administrator has enabled this feature.
> > 
> > Will the configuration file will have also an entry to control whether
> > the configuration file itself is polled? :-)
> 
> With the mapped file, there is no file polling as such, just a few
> memory loads.  The cost is that the system administrator needs to run a
> command after updating any of the covered configuration files, which is
> why this has to be optional (and opt-in per configuration file).  There
> probably aren't that many configuration files where this is needed.
> 

I think there's a caveat with memory mapped file: if a new version of 
the configuration file is created and renamed to the configuration
location, replacing the previous one, applications won't notice the
update, as the memory mapping will still reference the previous file.

Regards.

-- 
Yann Droneaud
OPTEYA