[CRIU] [PATCH] kdat: allow to override build time

[Bernhard M. Wiedemann]

On 2017-06-30 14:45, Pavel Emelyanov wrote:
> On 06/30/2017 12:59 PM, Bernhard M. Wiedemann wrote:
>> in order to allow for reproducible builds.
>> See https://reproducible-builds.org/ for why this is good
>> and https://reproducible-builds.org/specs/source-date-epoch/
>> for the definition of this variable.
> 
> Thanks, Brenhard!
> 
> Acked-by: Pavel Emelyanov <xemul at virtuoozo.com>
> 
> Is that the only thing that's required to make criu builds reproducible?
> Presumably not, so is there anything we can help you with to make it happen?

actually, it was the only diff I needed to have 2 builds produce
bit-identical results[1].
But we have a very normalized build environment with constant locale,
timezone, user, build path... so others may find more issues.

> I'm asking because criu's "build system", as you've noticed, is homegrown
> and is about to be constantly tuned and fixed (probably be replaced) in the
> future. So I'd like to align those potential changes with yours :)

It seems, we are closely following upstream with what we have in our
openSUSE Tumbleweed (aka Factory) package
because we already had your new line from 2017-05-04
and I'll keep monitoring it for packages that do not build reproducibly.

So not much to do right now.
When you make something new, you can try to get it right in the first
place by sorting directory listing, sorting hashes (aka associative
arrays), not including timestamps, hostnames, usernames and other build
time information into the build output (except things like logs that we
do not need to package).

And if you do not get it right, I might be back... with patches!

Ciao
Bernhard M.

P.S. I still wonder why my mails do not appear in
https://lists.openvz.org/pipermail/criu/2017-June/date.html
even though I subscribed to the ML 6h ago.

[1] my
https://github.com/bmwiedemann/reproducible-faketools/blob/master/bin/date
even allows to get identical results without that patch.