From 9bf12a864816ca3be1e55bf6c8d881f7d7124fb1 Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan@agner.ch>
Date: Mon, 14 Jun 2021 11:27:03 +0200
Subject: [PATCH] Use direct I/O for SPL update (#1408)

The rauc hook for the spl slotclass writes to the disk directly. Make
sure the changes do not end up in cache in case the device looses power
or is otherwise not properly rebooted.

Also use the same partition label detection we are using in
hassos-expand.
---
 buildroot-external/ota/rauc-hook | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/buildroot-external/ota/rauc-hook b/buildroot-external/ota/rauc-hook
index 7759a1fb1..92410492c 100755
--- a/buildroot-external/ota/rauc-hook
+++ b/buildroot-external/ota/rauc-hook
@@ -63,12 +63,14 @@ fi
 if [ "${RAUC_SLOT_CLASS}" = "spl" ]; then
     DEVICE_CHILD="$(findfs LABEL="hassos-boot")"
     DEVICE_ROOT="/dev/$(lsblk -no pkname "${DEVICE_CHILD}")"
+    PART_TABLE="$(sfdisk -lqJ "${DEVICE_ROOT}")"
+    PART_LABEL="$(echo "${PART_TABLE}" | jq -r '.partitiontable.label')"
 
-    if sfdisk -dq "${DEVICE_ROOT}" | grep -q 'label: gpt'; then
-        dd if="${RAUC_IMAGE_NAME}" of="${DEVICE_ROOT}" conv=notrunc bs=512 seek=2 skip=2
+    if [ "${PART_LABEL}" = "gpt" ]; then
+        dd if="${RAUC_IMAGE_NAME}" of="${DEVICE_ROOT}" conv=notrunc oflag=direct bs=512 seek=2 skip=2
     else
-        dd if="${RAUC_IMAGE_NAME}" of="${DEVICE_ROOT}" conv=notrunc bs=1 count=440
-        dd if="${RAUC_IMAGE_NAME}" of="${DEVICE_ROOT}" conv=notrunc bs=512 seek=1 skip=1
+        dd if="${RAUC_IMAGE_NAME}" of="${DEVICE_ROOT}" conv=notrunc oflag=direct bs=1 count=440
+        dd if="${RAUC_IMAGE_NAME}" of="${DEVICE_ROOT}" conv=notrunc oflag=direct bs=512 seek=1 skip=1
     fi
 fi