svn commit: r289421 - in head/etc: . mtree ntp

[Ian Lepore]

On Fri, 2015-10-16 at 14:04 +0000, Cy Schubert wrote:
> Author: cy
> Date: Fri Oct 16 14:04:16 2015
> New Revision: 289421
> URL: https://svnweb.freebsd.org/changeset/base/289421
> 
> Log:
>   Add default leap-seconds file. This should help ntp networks get
> the
>   leap second date correct
>   
>   Updates to the file can be obtained from ftp://time.nist.gov/pub/ o
> r
>   ftp://tycho.usno.navy.mil/pub/ntp/.
>   
>   Suggested by:	dwmalone
>   Reviewed by:	roberto, dwmalone, delphij
>   Approved by:	roberto
>   MFC after:	1 week

One thing about this change scares me.  In the ntpd documentation:

    If the leapseconds file is present, the leap bits for reference
    clocks and downstratum servers are ignored.

I can't determine from casual code examination (and I don't have time
to experiment now) whether that is true even if the file is expired.

The leapfile expires every six months, and users must update it using
some external mechanism, or they must have configured autokey stuff so
that updates can be accepted from peer servers.  In either case what
we've done is created a default configuration that is likely to fail
right out of the box, because at least for releases the file we deliver
will be expired before they even download and install the image.

At the very least I think we should hold off on MFC of this until we
know for sure whether an expired-but-present leapfile causes incorrect
operation.  If a pending leap notification in the leap bits of packets
from peer servers and refclocks will be honored when the file is
expired, then there is no problem with this change.

-- Ian