From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Fri, 17 Nov 2017 10:55:50 +0100 Subject: [Buildroot] [PATCH] systemd: set time epoch for reproducible builds In-Reply-To: <20171116170316.19081-1-john@metanate.com> References: <20171116170316.19081-1-john@metanate.com> Message-ID: <20171117105550.0c95e622@windsurf.lan> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net 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 $SOURCE_DATE_EPOCH to use a deterministic > timestamp when reproducible builds are enabled. > > Signed-off-by: John Keeping Hum, systemd uses 'stat -c %Y NEWS', which returns: %Y time of last data modification, seconds since Epoch I just extracted the systemd tarball with Buildroot, and: output/build/systemd-234 (master)$ 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