Re: [gentoo-amd64] Re: Wrong time after move to new timezone

[Dale]

Duncan wrote:
> Dale posted on Thu, 07 Jan 2016 00:55:31 -0600 as excerpted:
>
>>> You did the first part of it, setting /etc/timezone, but didn't do the
>>> second part, setting /etc/localtime, which is used by glibc to know
>>> your timezone.  You can either do it using the command in the handbook:
>>>
>>> emerge --config sys-libs/timezone-data
>>>
>>> ... or you can do it manually by copying the appropriate timezone file
>>> from /usr/share/zoneinfo/ to /etc/localtime, for AZ:
>>>
>>> cp /usr/share/zoneinfo/America/Phoenix /etc/localtime
>>>
>>> (Every time you update the timezone-data package, its pkg_postinst()
>>> runs pkg_config(), which is what that emerge call does semi-manually,
>>> above. pkg_config in turn copies the appropriate file to /etc/localtime
>>> based on /etc/timezone, thus updating /etc/localtime with the timezone
>>> file from the freshly installed timezone-data package.  The cp
>>> alternative simply does that same cp manually.  You can of course take
>>> a look at the timezone-data ebuild itself to see exactly how it does
>>> it, if you like. It does get slightly fancier with its logic, setting
>>> factory if the timezone is invalid, not touching the localtime file if
>>> it's a symlink instead of an actual file, etc, but basically, just does
>>> the above under normal circumstances. =:^)
>>>
>> It's been a long time since I did this but isn't that supposed to be a
>> link instead of a copy?  I'm pretty sure it was a link long ago but they
>> may have changed it.
> Take a look at the code in timezone-data's pkg_config.  It's commented
> and easy enough to follow for those who are comfortable with bash, as
> gentooers certainly /should/ be. =:^)
>
> That function (which is run as part of the handbook's installation
> instructions) checks for a symlink and specifically assumes the user
> knows what they are doing if it's a symlink, but defaults to a cp based
> on the timezone set in /etc/timezone, unless /etc/localtime is a symlink.
>
> So a symlink should work if a user creates it manually, but the file is
> normally copied.
>
> I'd guess the reason is because gentoo still tries to allow for a
> separate /usr, which would of course mean a dead symlink in early (pre-
> mount but for /) boot, which is when openrc tries to set the time, in
> ordered to properly check config file modification times to see if it
> needs to recache service ordering.  Openrc then falls back to I think
> UTC, which will likely trigger a time-skew complaint when the cache files
> appear to be from the future (for folks in UTC-minus timezones, anyway).
>
> For people with /usr/share/zoneinfo/* on / (or who use an initr* that
> mounts /usr), the symlink should work fine, and is arguably easier to
> check, since you can just check where the symlink points instead of
> having to diff against the zoneinfo timezone file you /think/ it should
> be to be sure it's correct (which is what I did here, checking my own
> system to be sure it was set that way, before posting).
>
> But while my /usr is on / (and I'm on systemd so that particular issue
> wouldn't apply, but others might), I've left localtime as an actual file,
> because that's the default solution, thus most widely tested and least
> likely to cause additional bugs.  I don't hesitate to diverge from the
> defaults where I have some reason to prefer doing it differently, and
> there are indeed lots of places I do just that and I sometimes see bugs
> nobody else seems to see as a result, but here, I don't really care, so
> I've picked my additional bug risks and don't find the need to make this
> one of them. =:^)
>


I'll take your word for it because I don't do bash.  I just need to
remember that it is changed now. 

Dale

:-)  :-)