From 4092869bc87d62c6f67236f59c13e3b9a255cdbe Mon Sep 17 00:00:00 2001 From: Paul Spooren Date: Wed, 23 Sep 2026 12:50:12 +0200 Subject: [PATCH] sata: make the boot partition reproducible The ext2 boot partition of the WD My Book Live images differs between builds: -Linux rev 1.0 ext2 filesystem data, UUID=8474430c-7c37-4000-95a5-1d8f4f0607d1 +Linux rev 1.0 ext2 filesystem data, UUID=4b8e89bb-aee0-4fde-971c-893df8d8fcd1 -drwxr-xr-x 0 1000 1000 0 2026-09-23 08:27:40.000000 ./boot/ +drwxr-xr-x 0 1000 1000 0 2026-09-23 10:17:28.000000 ./boot/ genext2fs copies owner, mode and mtime of the staged files from the host and adds them in readdir() order, which also decides their inode numbers and blocks. It leaves the UUID empty, so e2fsck fills in a random one, and e2fsck stamps the last check with the current time. Pass genext2fs a name sorted tarball with root ownership, group and other write permission dropped and mtimes clamped to SOURCE_DATE_EPOCH, derive the UUID from the file system contents and run e2fsck with E2FSCK_TIME set to SOURCE_DATE_EPOCH. Remove the staging directory and the tarball afterwards. Link: https://github.com/openwrt/openwrt/pull/25357 Signed-off-by: Paul Spooren --- target/linux/apm821xx/image/Makefile | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/target/linux/apm821xx/image/Makefile b/target/linux/apm821xx/image/Makefile index 1f09f8de756..966ebff62d4 100644 --- a/target/linux/apm821xx/image/Makefile +++ b/target/linux/apm821xx/image/Makefile @@ -11,14 +11,24 @@ define Build/boot-img $(CP) $(KDIR)/image-$(firstword $(DEVICE_DTS)).dtb $@.bootdir/boot/$(DEVICE_DTB) $(CP) $(IMAGE_KERNEL) $@.bootdir/boot/uImage + $(TAR) -C $@.bootdir -cf $@.bootdir.tar --sort=name --numeric-owner \ + --owner=0 --group=0 --mode=go-w \ + $(if $(SOURCE_DATE_EPOCH),--mtime="@$(SOURCE_DATE_EPOCH)" --clamp-mtime) \ + boot + genext2fs --block-size $(BLOCKSIZE:%k=%Ki) \ --size-in-blocks $$((1024 * $(CONFIG_TARGET_KERNEL_PARTSIZE))) \ - --root $@.bootdir $@.boot + --tarball $@.bootdir.tar $@.boot # convert it to revision 1 - needed for u-boot ext2load - $(STAGING_DIR_HOST)/bin/tune2fs -O filetype $@.boot + $(STAGING_DIR_HOST)/bin/tune2fs -O filetype \ + -U $(patsubst %00,%01,$(IMG_PART_DISKGUID)) \ + $@.boot # Ignore errors because file system was intentionally broken with tune2fs - -$(STAGING_DIR_HOST)/bin/e2fsck -pDf $@.boot > /dev/null + -$(if $(SOURCE_DATE_EPOCH),E2FSCK_TIME=$(SOURCE_DATE_EPOCH)) \ + $(STAGING_DIR_HOST)/bin/e2fsck -pDf $@.boot > /dev/null + + rm -rf $@.bootdir $@.bootdir.tar endef define Build/boot-script