~/.localtime ?

[Andreas Jaeger]

On Thursday, March 01, 2012 14:15:44 Roland McGrath wrote:
> Running programs are not going to be reliably affected unless you
> provoke them to call tzset or equivalent, anyway.  Having things
> stat'ing a file implicitly all the time just to see if it changed is
> not viable because of the performance hit and unwanted exposure to
> filesystem flakiness.  So I don't think you can reasonably get what
> you're after this way.  Having things refer to a new file implicitly
> has all sorts of other complications wrt security concerns and so on.

Roland,

To display the local time, functions call localtime - and that one invokes 
already tzset.

AFAIU changing /etc/localtime changes already today the time of the desktop 
clocks running on a system, so my proposal would indeed add a second 
location - and we should stat ~/.localtime first and only stat 
/etc/localtime if ~/.localtime does not exist.

I talked with our security guys - they came up with this proposal ;) - and 
I don't see a security concern here for displaying the users localtime.

Andreas
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