Re: host unresponsive when setting time very far in the future

On Mon, Oct 17, 2022 at 12:05 PM Jan Schaumann <jschauma@netmeister.org> wrote:
>
> Warner Losh <imp@bsdimp.com> wrote:
>
> > We do know that if the year (tm_year) overflows an int (32-bit signed),
> > we'll
> > have problems. It would be approximately year 2,147,483,648 (since I think
> > the limitation is signed, not unsigned, but if unsigned it's 4294967296
> > instead).
>
> Right, though since tm_year is defined as "year ­
> 1900", I'd expect to be able to reach 12/31 23:59:59
> in 2,147,485,547, as on e.g., NetBSD and Linux:
>
>  netbsd$ date -r 67768036191676799
>  Wed Dec 31 23:59:59 UTC 2147485547
>
>  linux$ date --date '@67768036191676799'
>  Wed Dec 31 11:59:59 PM UTC 2147485547
>
> But FreeBSD:
>  freebsd$ date -r 67768036191676799
>  date: invalid time
>  freebsd$ date -r 67767976233532799
>  Tue Dec 31 23:59:59 UTC 2147483647
>
> Kinda unclear to me how FreeBSD ended up with a
> tm_year value that's not 1900 based here?
>
> > Anything beyond that we know definitely won't work. Why we fall short
> > and "only" make it to year 1.561,694,399, I don't know the root
> > cause of. It's not even a nice, round multiple of the above...
>
> Regardless of the root cause, though, I think
> something somewhere should return EINVAL before the
> system freaks out. :-)
>
> -Jan

Definitely.  And the place that should do it is clock_ts_to_ct, where
the assertions were added in git rev 90a79ac5765 .  They should be
converted from assertions into EINVALs.
-Alan