[OE-core] [PATCH 3/4] image-preling.bbclass: support binary reproducibility

[Juro Bystricky]

Conditionally support binary reproducibility in built images.
If BUILD_REPRODUCIBLE_BINARIES = 1 then:

1. Do not randomize library addresses
2. Set/export PRELINK_TIMESTAMP to a reproducible value.
   The value is derived from the top git commit.

Signed-off-by: Juro Bystricky <juro.bystricky at intel.com>
---
 meta/classes/image-prelink.bbclass | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/meta/classes/image-prelink.bbclass b/meta/classes/image-prelink.bbclass
index 4157df0..78ef65a 100644
--- a/meta/classes/image-prelink.bbclass
+++ b/meta/classes/image-prelink.bbclass
@@ -36,7 +36,14 @@ prelink_image () {
 	dynamic_loader=$(linuxloader)
 
 	# prelink!
-	${STAGING_SBINDIR_NATIVE}/prelink --root ${IMAGE_ROOTFS} -amR -N -c ${sysconfdir}/prelink.conf --dynamic-linker $dynamic_loader
+	if [ "$BUILD_REPRODUCIBLE_BINARIES" = "1" ]; then
+		bbnote " prelink: BUILD_REPRODUCIBLE_BINARIES..."
+		# SOURCE_DATE_EPOCH is 0 (no soure files), so get the timestamp from GIT repo...
+		export PRELINK_TIMESTAMP=`git log -1 --pretty=%ct `
+		${STAGING_SBINDIR_NATIVE}/prelink --root ${IMAGE_ROOTFS} -am -N -c ${sysconfdir}/prelink.conf --dynamic-linker $dynamic_loader
+	else
+		${STAGING_SBINDIR_NATIVE}/prelink --root ${IMAGE_ROOTFS} -amR -N -c ${sysconfdir}/prelink.conf --dynamic-linker $dynamic_loader
+	fi
 
 	# Remove the prelink.conf if we had to add it.
 	if [ "$dummy_prelink_conf" = "true" ]; then
-- 
2.7.4