Re: [PATCH] t4212: handle systems with post-apocalyptic gmtime

> >>  - teach the "is the result sane, even though we may have got a
> >>    non-NULL from gmtime?  otherwise let's signal a failure by
> >>    replacing it with a known sentinel value" codepath the new
> >>    failure mode Charles's report suggests---if we feed a positive
> >>    timestamp and gmtime gave us back a tm_year+1900 < 0, that is
> >>    certainly an overflow; and
> >
> > I don't think we can analyze the output from gmtime. If it wraps the
> > year at N, then won't N+2014 look like a valid value?
> 
> Yes, but I was hoping that there are small number of possible N's
> ;-)

> > diff --git a/date.c b/date.c
> > index e1a2cee..e0c43c4 100644
> > --- a/date.c
> > +++ b/date.c
> > @@ -57,6 +57,8 @@ static time_t gm_time_t(unsigned long time, int tz)
> >  static struct tm *time_to_tm(unsigned long time, int tz)
> >  {
> >  	time_t t = gm_time_t(time, tz);
> > +	if (t > 9999999999999999)
> > +		return NULL;
> >  	return gmtime(&t);
> >  }
> >
> > I suspect that would handle the FreeBSD case, as well.
> >
> > By the way, I have a suspicion that the gm_time_t above can overflow if
> > you specially craft a value at the edge of what time_t can handle (we
> > check that our value will not overflow time_t earlier, but now we might
> > be adding up to 86400 seconds to it). <sigh>
> 
> Yuck.  Let's not go there.