Re: git: fc43a1b6842a - stable/14 - tzsetup: symlink /etc/localtime instead of copying

On 8/8/24 00:35, Sean C. Farley wrote:
> On Thu, 1 Aug 2024, Ed Maste wrote:
> 
>> The branch stable/14 has been updated by emaste:
>>
>> URL: https://cgit.FreeBSD.org/src/commit/?id=fc43a1b6842afa806dfd7ba48de5bece63d04456
>>
>> commit fc43a1b6842afa806dfd7ba48de5bece63d04456
>> Author:     Ed Maste <emaste@FreeBSD.org>
>> AuthorDate: 2022-10-14 16:44:35 +0000
>> Commit:     Ed Maste <emaste@FreeBSD.org>
>> CommitDate: 2024-08-01 15:11:45 +0000
>>
>>     tzsetup: symlink /etc/localtime instead of copying
>>
>>     Using a symlink means that new timezone data (installed by an errata
>>     update, say) will be usable without having to be copied again.
>>
>>     Reviewed by:    bapt, kevans, philip
>>     Sponsored by:   The FreeBSD Foundation
>>     Differential Revision: https://reviews.freebsd.org/D37005
>>
>>     (cherry picked from commit 5e16809c953f4cd19fadb1767469dec319de0353)
> 
> I ran across an issue with this when using "etcupdate -D" to update a
> jail from the host.  "tzsetup -r -C /tmp/chroot", as called by
> etcupdate, prepends the path of the chroot to the link which breaks
> things inside the jail.
> 
> For example, if you run the following:
> mkdir -p /tmp/chroot/etc
> mkdir -p /tmp/chroot/usr/share
> mkdir -p /tmp/chroot/var/db
> ln -s /usr/share/misc /tmp/chroot/usr/share/misc
> ln -s /usr/share/zoneinfo /tmp/chroot/usr/share/zoneinfo
> cp /var/db/zoneinfo /tmp/chroot/var/db/.
> tzsetup -C /tmp/chroot -r
> 
> The result will be the following:
> /tmp/chroot/etc/localtime@ -> /tmp/chroot//usr/share/zoneinfo/America/Indiana/Indianapolis

Hmm, we also intentionally moved away from symlinks to copying many years ago.
We added /var/db/zoneinfo so that tzsetup -r would know which file to copy
into /etc after we moved away from the symlink I thought?

It looks like tzsetup switched to copying by default longer ago than I
remembered though in 1996 (commit c78cc02b89f6f5e562e5cf93d54faaa1bd79dfef),
though that replaced an older change that switched from copying to
symbolic links (2d71a1f121460406695c914b4f35e2e365010855).  Presumably though
-r shouldn't do anything if /etc/localtime is a symlink?  I thought the only
reason it was added was due to using copies:

commit ada5f18a1b161e4fd99966444f85ca51d5a3fd8a
Author: Edwin Groothuis <edwin@FreeBSD.org>
Date:   Tue Oct 20 06:54:31 2009 +0000

     Instead of having to know which timezone was picked last time, you
     now can run "tzsetup -r" which will reinstall the last choice. This
     data is recorded in /var/db/zoneinfo.
     
     MFC after:       1 week

Notes:
     svn path=/head/; revision=198267


-- 
John Baldwin