[Buildroot] [PATCH 03/10 v3] support/download: add helper to generate a reproducible archive

[Arnout Vandecappelle]

On 29/12/2020 12:01, Yann E. MORIN wrote:
> We currently need to generate reproducible archives in at least two
> locations: the git and svn download backends. We also know of some
> future potential use (e.g. the other download backends, like cvs, or
> in the upcoming download post-processors for vendoring, like cargo
> and go).
> 
> However, we are currently limited to a narrow range of tar versions
> that we support, to create reproducible archives, because the gnu
> format we use has changed with tar 1.30.
> 
> As a consequence, and as time advances, more and more distros are,
> or will eventually start, shipping with tar 1.30 or later, and thus
> we need to always build our on host-tar.
> 
> Now, thanks to some grunt work by Vincent, we have a set of options
> that we can pass tar, to generate reproducible archives back from
> tar-1.27 and up through tar-1.32, the latest released version.
> 
> However, those options are non-trivial, so we do not want to have
> to repeat those (and maintain them) in multiple locations.
> 
> Introduce a helper that can generate a reproducible archive from
> an input directory.
> 
> The --pax-option, to set specific PAX headers, does not accept
> RFC2822 timestamps which value are too away from some fixed point
> (set atcompile-time?):
>     tar: Time stamp is out of allowed range
> 
> However, the same timestamps passed as strict compliant ISO 8601 are
> accepted, so that's what we expect as a date format.
> 
> Signed-off-by: Yann E. MORIN <yann.morin.1998 at free.fr>
> Cc: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
> Cc: Vincent Fazio <vfazio at xes-inc.com>

Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout at mind.be>

 Regards,
 Arnout