[openwrt/openwrt] scripts/gen_image_generic.sh: generate reproducible EFI filesystem

[LEDE Commits]

dangole pushed a commit to openwrt/openwrt.git, branch openwrt-22.03:
https://git.openwrt.org/5e617186404ce578adf4ec3f2f1c90fd671c8f9b

commit 5e617186404ce578adf4ec3f2f1c90fd671c8f9b
Author: Daniel Golle <daniel at makrotopia.org>
AuthorDate: Mon Apr 11 15:25:27 2022 +0100

    scripts/gen_image_generic.sh: generate reproducible EFI filesystem
    
    Generate FAT filesystem for EFI boot in a reproducible way:
     * use '--invariant' option of mkfs.fat
     * set timestamps of all files to SOURCE_DATE_EPOCH
     * make sure files are ordered locale-independent
    
    Signed-off-by: Daniel Golle <daniel at makrotopia.org>
    (cherry picked from commit aece8f5ae8d15e5e79b8e34a176895209709afb6)
---
 scripts/gen_image_generic.sh | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/scripts/gen_image_generic.sh b/scripts/gen_image_generic.sh
index 6a01c813d7..5e37224736 100755
--- a/scripts/gen_image_generic.sh
+++ b/scripts/gen_image_generic.sh
@@ -31,8 +31,9 @@ dd if="$ROOTFSIMAGE" of="$OUTPUT" bs=512 seek="$ROOTFSOFFSET" conv=notrunc
 
 if [ -n "$GUID" ]; then
     [ -n "$PADDING" ] && dd if=/dev/zero of="$OUTPUT" bs=512 seek="$((ROOTFSOFFSET + ROOTFSSIZE))" conv=notrunc count="$sect"
-    mkfs.fat -n kernel -C "$OUTPUT.kernel" -S 512 "$((KERNELSIZE / 1024))"
-    mcopy -s -i "$OUTPUT.kernel" "$KERNELDIR"/* ::/
+    mkfs.fat --invariant -n kernel -C "$OUTPUT.kernel" -S 512 "$((KERNELSIZE / 1024))"
+    [ "$SOURCE_DATE_EPOCH" ] && find "$KERNELDIR"/ -mindepth 1 -execdir touch -hcd "@${SOURCE_DATE_EPOCH}" "{}" +
+    LC_ALL=C mcopy -m -s -i "$OUTPUT.kernel" "$KERNELDIR"/* ::/
 else
     make_ext4fs -J -L kernel -l "$KERNELSIZE" ${SOURCE_DATE_EPOCH:+-T ${SOURCE_DATE_EPOCH}} "$OUTPUT.kernel" "$KERNELDIR"
 fi