GNU bug report logs - #21111
GNU tar warns about zeroed timestamps in binary tarball

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 21111 in the body.
You can then email your comments to 21111 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Dave Love <fx <at> gnu.org>
To: bug-guix <at> gnu.org
Subject: possibly bogus in binary tarball
Date: Wed, 22 Jul 2015 12:55:13 +0100

The timestamps in the guix-binary-0.8.3.x86_64-linux.tar.xz tarball are
all at the epoch, so unpacking it spews messages like

  tar: ./var/guix: implausibly old time stamp 1970-01-01 01:00:00

I guess that's not intentional, but if it is, it's probably worth a note
in the installation instructions.

Message #8 received at 21111 <at> debbugs.gnu.org (full text, mbox):

From: Andreas Enge <andreas <at> enge.fr>
To: Dave Love <fx <at> gnu.org>
Cc: 21111 <at> debbugs.gnu.org
Subject: Re: bug#21111: possibly bogus in binary tarball
Date: Wed, 22 Jul 2015 14:27:21 +0200

On Wed, Jul 22, 2015 at 12:55:13PM +0100, Dave Love wrote:
> The timestamps in the guix-binary-0.8.3.x86_64-linux.tar.xz tarball are
> all at the epoch, so unpacking it spews messages like
> 
>   tar: ./var/guix: implausibly old time stamp 1970-01-01 01:00:00
> 
> I guess that's not intentional, but if it is, it's probably worth a note
> in the installation instructions.

It is intentional, as part of making things deterministic.

Andreas

Message #11 received at 21111 <at> debbugs.gnu.org (full text, mbox):

From: ludo <at> gnu.org (Ludovic Courtès)
To: Andreas Enge <andreas <at> enge.fr>
Cc: 21111 <at> debbugs.gnu.org, Dave Love <fx <at> gnu.org>
Subject: Re: bug#21111: possibly bogus in binary tarball
Date: Wed, 22 Jul 2015 17:55:01 +0200

Andreas Enge <andreas <at> enge.fr> skribis:

> On Wed, Jul 22, 2015 at 12:55:13PM +0100, Dave Love wrote:
>> The timestamps in the guix-binary-0.8.3.x86_64-linux.tar.xz tarball are
>> all at the epoch, so unpacking it spews messages like
>> 
>>   tar: ./var/guix: implausibly old time stamp 1970-01-01 01:00:00
>> 
>> I guess that's not intentional, but if it is, it's probably worth a note
>> in the installation instructions.
>
> It is intentional, as part of making things deterministic.

Right.

Interestingly, I do not get this message, both with ‘tar xf’ and
‘tar xvf’ with GNU tar 1.28.

I tried with different timezones, and I can’t trigger it.

Dave: What version of GNU tar do you use, and in what timezone?

TIA,
Ludo’.

Message #14 received at 21111 <at> debbugs.gnu.org (full text, mbox):

From: Dave Love <fx <at> gnu.org>
To: Ludovic Courtès <ludo <at> gnu.org>
Cc: 21111 <at> debbugs.gnu.org, Andreas Enge <andreas <at> enge.fr>
Subject: Re: bug#21111: possibly bogus in binary tarball
Date: Wed, 22 Jul 2015 21:26:49 +0100

Ludovic Courtès <ludo <at> gnu.org> writes:

> Interestingly, I do not get this message, both with ‘tar xf’ and
> ‘tar xvf’ with GNU tar 1.28.
>
> I tried with different timezones, and I can’t trigger it.
>
> Dave: What version of GNU tar do you use, and in what timezone?
>
> TIA,
> Ludo’.

It was on RHEL6 in the UK zone

  $ grep -I zone /etc/sysconfig/clock
  ZONE="Europe/London"
  
with:

  $ rpm -q tar
  tar-1.23-11.el6.x86_64

There aren't any obviously-relevant patches in the tar package changelog.

I think it would be worth a note on the timestamps anyway to avoid
confusion and make sure they're maintained, if they should be.  (Excuse
me if that's done somewhere, but I just went to the current installation
instructions.)

Message #21 received at 21111-done <at> debbugs.gnu.org (full text, mbox):

From: ludo <at> gnu.org (Ludovic Courtès)
To: Dave Love <fx <at> gnu.org>
Cc: Andreas Enge <andreas <at> enge.fr>, 21111-done <at> debbugs.gnu.org
Subject: Re: bug#21111: possibly bogus in binary tarball
Date: Wed, 22 Jul 2015 22:59:05 +0200

Dave Love <fx <at> gnu.org> skribis:

> Ludovic Courtès <ludo <at> gnu.org> writes:
>
>> Interestingly, I do not get this message, both with ‘tar xf’ and
>> ‘tar xvf’ with GNU tar 1.28.
>>
>> I tried with different timezones, and I can’t trigger it.
>>
>> Dave: What version of GNU tar do you use, and in what timezone?
>>
>> TIA,
>> Ludo’.
>
> It was on RHEL6 in the UK zone
>
>   $ grep -I zone /etc/sysconfig/clock
>   ZONE="Europe/London"
>   
> with:
>
>   $ rpm -q tar
>   tar-1.23-11.el6.x86_64
>
> There aren't any obviously-relevant patches in the tar package changelog.

According to the 1.28 manual (info "(tar) warnings"), this specific
warning can be explicitly enabled with --warning=timestamp.

However, I tried variations of the following command with no luck:

  TZ=Europe/London tar --warning=timestamp --extract -f \
    guix-binary-0.8.3.i686-linux.tar.xz

So maybe the fact that 1.28 doesn’t emit the warning is a bug.

> I think it would be worth a note on the timestamps anyway to avoid
> confusion and make sure they're maintained, if they should be.  (Excuse
> me if that's done somewhere, but I just went to the current installation
> instructions.)

I’ve added this to the installation instructions in commit aafa0df:

   Some versions of GNU tar raise a warning about “implausibly old
   time stamps”.  This is because all the files in the archive have
   their modification time set to zero (which means January 1st,
   1970.)  This is done on purpose to make sure the archive content is
   independent of its creation time, thus making it reproducible.

Thanks!

Ludo’.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.