Kind of solved.. [WAS: Re: Linux compat 2.6.16 reports time incorrect?]

[Jeremy Messenger]

On Tue, 21 Oct 2008 16:16:50 -0500, Per Hedeland <per at hedeland.org> wrote:

> "Jeremy Messenger" <mezz7 at cox.net> wrote:
>>
>> It won't work, because if you read Boris's ktrace and you will see it
>> reads in /etc/localtime.
>
> Boris' ktrace did indeed show that (though I don't know how he deduced
> that the file was "rejected", rather than read three times due simply to
> sloppy programming) - but he didn't mention whether he got the time
> difference between native and Linux 'date' that you reported.
>
>> So if I copy it to /compat/linux/etc/localtime
>> and it won't makes any difference, since it's same file. :-)
>
> But we haven't seen a trace from *your* system - if you actually have
> (or had) a /compat/linux/etc/localtime file, it will of course be read
> and no fall-through to /etc/localtime will happen - and if
> /compat/linux/etc/localtime has the wrong contents, you will get the
> wrong output from Linux 'date'.

We get same trace, but only a bit different on read "TZif\0\0\0[...]"  
part. I ran ktrace/linux_kdump with no /compat/linux/etc/localtime and  
it's complete default beside of that OVERRIDE_LINUX_BASE_PORT=f8 and  
compat.linux.osrelease=2.6.16.

http://people.freebsd.org/~mezz/date_linux_kdump.txt

>> I have downloaded tzdata-2008h-1.fc8.noarch.rpm and extracted it. Then
>> copy it in /compat/linux/etc/localtime and now it works correct. Only a
>> few seconds difference, but does not matter to me.
>
> And if you remove it, i.e. no /compat/linux/etc/localtime at all, what
> is the result? Not having it would seem to be the sane solution - it's
> certainly the case for linux_base-fc-4.

I don't have any /compat/linux/etc/localtime with both linux_base-fc-4 and  
linux_base-f8. The FreeBSD's tzdata is from 2004, so with linux_base-f8's  
tzdata 2008[a-z] does not work with FreeBSD's /etc/localtime. It's what I  
think this is problem for changed format in tzdata 2008[a-z], but I might  
be wrong. If it is indeed this problem, then it looks like we might have  
to add install tzdata-2008h-1.fc8.noarch.rpm and document it to tell users  
to copy the file by manual to have the time/date correct.

Cheers,
Mezz

> The /etc/localtime file on Linux as on FreeBSD is just a copy of (or
> link to) the appropriate zic-compiled Olson zone file - I can't claim to
> have investigated it, but changing the compiled format would seem to be
> out of the question, since it would wreak havoc with all the many Unix
> systems that use these files (and that periodically have to update them
> to cater to the whims of politicians all over the world).
>
> Hm, I guess it's possible that FC modified 'zic' from what comes with
> the Olson files (and their libc functions that read it to match) - but
> even that would seem incredibly unlikely I think, just asking for
> trouble.
>
> --Per Hedeland


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FreeBSD GNOME Team
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