> Date: Fri, 18 Jun 2021 09:29:44 +0200
> From: Claudio Jeker <cje...@diehard.n-r-g.com>
>
> On Thu, Jun 17, 2021 at 08:41:39PM -0500, Scott Cheloha wrote:
> > On Fri, Jun 11, 2021 at 12:17:02PM -0500, Scott Cheloha wrote:
> > > Hi,
> > >
> > > setitimer(2) has a one hundred million second upper bound for timers.
> > > Any timer interval larger than this is considered invalid and we set
> > > EINVAL.
> > >
> > > There is no longer any reason to use this particular limit. Kclock
> > > timeouts support the full range of a timespec, so we can trivially
> > > increase the upper bound without any practical risk of overflow.
> > >
> > > This patch increases the upper bound to UINT_MAX seconds.
> > >
> > > Why UINT_MAX? UINT_MAX is the largest possible input to alarm(3). We
> > > could then simplify the alarm(3) manpage and the libc alarm.c code in
> > > a subsequent patch. POSIX says alarm(3) "is always successful". Our
> > > implementation can fail. It would be nicer/simpler if ours were free
> > > of failure modes.
> > >
> > > ok?
> >
> > 1 week bump.
> >
> > Updated patch: make the maximum value ("max") static and const.
>
> OK claudio@
>
> I wonder if we need a max at all? I guess there is an upper limit to not
> overflow the time_t when calculating the absolute timeout but that is
> probably close to LLONG_MAX / 2.
Not really worth worrying about. Youu'll be long dead once that alarm
expires ;).
> I think a simplified version of alarm(3) that never fails would be nice.
>
> > Index: kern_time.c
> > ===================================================================
> > RCS file: /cvs/src/sys/kern/kern_time.c,v
> > retrieving revision 1.153
> > diff -u -p -r1.153 kern_time.c
> > --- kern_time.c 11 Jun 2021 16:36:34 -0000 1.153
> > +++ kern_time.c 18 Jun 2021 01:40:42 -0000
> > @@ -709,15 +709,16 @@ out:
> > int
> > itimerfix(struct itimerval *itv)
> > {
> > + static const struct timeval max = { .tv_sec = UINT_MAX, .tv_usec = 0 };
> > struct timeval min_interval = { .tv_sec = 0, .tv_usec = tick };
> >
> > if (itv->it_value.tv_sec < 0 || !timerisvalid(&itv->it_value))
> > return EINVAL;
> > - if (itv->it_value.tv_sec > 100000000)
> > + if (timercmp(&itv->it_value, &max, >))
> > return EINVAL;
> > if (itv->it_interval.tv_sec < 0 || !timerisvalid(&itv->it_interval))
> > return EINVAL;
> > - if (itv->it_interval.tv_sec > 100000000)
> > + if (timercmp(&itv->it_interval, &max, >))
> > return EINVAL;
> >
> > if (!timerisset(&itv->it_value))
> >
>
> --
> :wq Claudio
>
>
