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Date:   Tue, 08 Oct 2019 09:54:43 +0000
To:     Masahiro Yamada <yamada.masahiro@socionext.com>
From:   Dmitry Goldin <dgoldin@protonmail.ch>
Cc:     Andreas Schwab <schwab@linux-m68k.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        "linux-kernel\\\\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "joel\\\\@joelfernandes.org" <joel@joelfernandes.org>,
        Ben Hutchings <ben@decadent.org.uk>
Reply-To: Dmitry Goldin <dgoldin@protonmail.ch>
Subject: Re: [PATCH v2] kheaders: making headers archive reproducible
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=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90 Original Me=
ssage =E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90
On Tuesday, October 8, 2019 10:14 AM, Masahiro Yamada <yamada.masahiro@soci=
onext.com> wrote:

> On Tue, Oct 8, 2019 at 5:07 PM Dmitry Goldin dgoldin@protonmail.ch wrote:
>
> > Hmm. --sort was introduced in 1.28 in 2014. Do you think it would warra=
nt some sort of version check and fallback or is this something we can expe=
ct the user to handle if their distribution happens to not ship anything mo=
re recent? A few sensible workarounds come to mind.
>
> I think the former.

After pondering it briefly, maybe substituting the option is a bit less has=
sle than checking for
the version and then degrading to a possibly non-reproducible archive.

Maybe we could go with something like the sketch below to replace --sort=3D=
name. That is, if
that's the only problematic flag.

find $cpio_dir -printf "%P\n" | LC_ALL=3DC sort | \
    tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=3D$KBUILD_BUILD_TIMESTAMP}" \
    --owner=3D0 --group=3D0 --numeric-owner \
    -Jcf $tarfile -C $cpio_dir/ -T - > /dev/null

I will look at this a bit more closely and give it a test-run later today o=
r early tomorrow. Then we can decide if its sufficient before submitting an=
other patch. Other suggestions and pointers are welcome, of course.

--
Best regards,
    Dmitry