[Buildroot] [PATCH] systemd: set time epoch for reproducible builds
Thomas Petazzoni
thomas.petazzoni at free-electrons.com
Fri Nov 17 09:55:50 UTC 2017
Hello,
On Thu, 16 Nov 2017 17:03:16 +0000, John Keeping wrote:
> Systemd embeds a timestamp which is used to impose a minimum bound on
> the system time during boot. Normally this comes from stat'ing the NEWS
> file included with the systemd source, but this makes the build
> non-reproducible. Pass in $SOURCE_DATE_EPOCH to use a deterministic
> timestamp when reproducible builds are enabled.
>
> Signed-off-by: John Keeping <john at metanate.com>
Hum, systemd uses 'stat -c %Y NEWS', which returns:
%Y time of last data modification, seconds since Epoch
I just extracted the systemd tarball with Buildroot, and:
output/build/systemd-234 (master)$ stat NEWS
File: NEWS
Size: 378872 Blocks: 744 IO Block: 4096 regular file
Device: 10302h/66306d Inode: 34473900 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 1000/ thomas) Gid: ( 1000/ thomas)
Access: 2017-11-17 10:51:07.369562977 +0100
Modify: 2017-07-12 16:01:10.000000000 +0200
Change: 2017-11-17 10:51:07.510563710 +0100
Birth: -
So the modification date is July 12th, and not today. So for a given
systemd release, the output of "stat -c %Y NEWS" is therefore stable,
and will not change.
Look:
$ stat -c %Y NEWS
1499868070
$ date -d @1499868070 +%Y-%m-%d
2017-07-12
So I'm not sure why your patch would be necessary. Could you check
what's going on?
Thanks!
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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