Re: Possible file date related bug in modern GNU tar?

[Joerg Schilling]

Peter Dyballa <Peter_Dyballa@Web.DE> wrote:

> The Apple supplied versions of /usr/bin/gnutar in PPC Tiger (Mac OS X 
> 10.4.11) and PPC Leopard (Mac OS X 10.5.8), 1.14 resp. 1.15.1, show since 
> some time warnings like this
>
>       /usr/bin/gnutar: meson-0.55.3/COPYING: implausibly old time stamp 
> 1970-01-01 01:00:00
>
> that I noticed recently when untarring an archive (meson-0.55.3.tar.gz in 
> this case, but there is about a dozen more TAR files that show this). These 
> "implausibly old time stamps" are also preserved by using means like Python's 
> pip installer.

A timestamp value of 0 is not forbidden. The POSIX.1/1988 tar format supports 
any non-negative value.

The tar you are using to unpack does not support POSIX.1/2001 Tar extensions 
and the TAR program that was used to create the archive could be seen to be 
buggy since it encoded the value to 0 even though the right value is correctly
representable in an 11 bit unsigned number.

> Of course up-to-date GNU tar 1.32 shows a reasonable date '2020-08-15 18:27'.

This is because the recent gnu tar supports to read POSIX.1/2001 tar extensions.

Jörg

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