[ptxdist] [PATCH v2] image-rauc: pick up hook script if it exists

[Roland Hieber <rhi@pengutronix.de>]

Introduce a new kconfig option to package a hook script into the RAUC
bundle and reference it in the manifest. Otherwise leave the [hooks]
section in the manifest empty. The hook script is searched
config/images/rauc-hooks.sh in the usual search locations. RAUC will
complain if a hook script is referenced but no hook script is found in
the image (i.e. IMAGE_RAUC_HOOK_SCRIPT is empty).

As hooks that should be called by RAUC need to be mentioned in the
manifest too (in the relevant slot or the [bundle] section), the image
config will still need to be forked by BSPs in order to adapt the
manifest for that use case. However, the mechanism to find the hook
script is then already in place, and can be used as-is.

Signed-off-by: Roland Hieber <rhi@pengutronix.de>
---
PATCH v2:
 - introduce an explicit kconfig option

PATCH v1: https://lore.ptxdist.org/ptxdist/20231106105534.3640846-1-rhi@pengutronix.de
---
 config/images/rauc.config |  4 ++++
 platforms/image-rauc.in   |  9 +++++++++
 rules/image-rauc.make     | 15 +++++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/config/images/rauc.config b/config/images/rauc.config
index e4169cc8cd95..4a6b34deee29 100644
--- a/config/images/rauc.config
+++ b/config/images/rauc.config
@@ -1,6 +1,7 @@
 image @IMAGE@ {
 	rauc {
 		file root.tar.gz { image = "root.tgz" }
+		@RAUC_HOOK_FILE@
 		manifest = "
 			[update]
 			compatible=@RAUC_BUNDLE_COMPATIBLE@
@@ -11,6 +12,9 @@ image @IMAGE@ {
 			[bundle]
 			format=@RAUC_BUNDLE_FORMAT@
 
+			[hooks]
+			@RAUC_HOOK_MANIFEST@
+
 			[image.rootfs]
 			filename=root.tar.gz
 			"
diff --git a/platforms/image-rauc.in b/platforms/image-rauc.in
index 391956a42f81..2070cf0069c1 100644
--- a/platforms/image-rauc.in
+++ b/platforms/image-rauc.in
@@ -58,4 +58,13 @@ config IMAGE_RAUC_INTERMEDIATE
 	  verification. The certificates must be stored in the CA of the
 	  "update-intermediate" role of the code signing provider.
 
+config IMAGE_RAUC_HOOK
+	bool "include hook script"
+	help
+	  If you enable this option and create a file named
+	  config/images/rauc-hooks.sh in any PTXDIST_PATH component, it will be
+	  included in the bundle and declared as a hook script in the manifest.
+	  Note that you still need to define the respective install or slot
+	  hooks in the manifest so that RAUC calls them.
+
 endif
diff --git a/rules/image-rauc.make b/rules/image-rauc.make
index 23d8d83b5251..e267e78c68f2 100644
--- a/rules/image-rauc.make
+++ b/rules/image-rauc.make
@@ -19,6 +19,10 @@ IMAGE_RAUC		:= image-rauc
 IMAGE_RAUC_DIR		:= $(BUILDDIR)/$(IMAGE_RAUC)
 IMAGE_RAUC_IMAGE	:= $(IMAGEDIR)/update.raucb
 IMAGE_RAUC_CONFIG	:= rauc.config
+IMAGE_RAUC_HOOK_FILE	:= $(call ptx/in-path, PTXDIST_PATH, config/images/rauc-hooks.sh)
+
+$(call ptx/cfghash, IMAGE_RAUC, $(IMAGE_RAUC_HOOK_FILE))
+$(call ptx/cfghash-file, IMAGE_RAUC, $(IMAGE_RAUC_HOOK_FILE))
 
 # ----------------------------------------------------------------------------
 # Image
@@ -36,6 +40,16 @@ ifdef PTXCONF_IMAGE_RAUC_BUNDLE_FORMAT_CRYPT
 IMAGE_RAUC_BUNDLE_FORMAT := "crypt"
 endif
 
+ifdef PTXCONF_IMAGE_RAUC_HOOK
+IMAGE_RAUC_ENV_HOOK = \
+	RAUC_HOOK_FILE="file hooks.sh { image = \\"$(IMAGE_RAUC_HOOK_FILE)\\" }" \
+	RAUC_HOOK_MANIFEST="filename=hooks.sh"
+else
+IMAGE_RAUC_ENV_HOOK = \
+	RAUC_HOOK_FILE="" \
+	RAUC_HOOK_MANIFEST=""
+endif
+
 IMAGE_RAUC_ENV	= \
 	$(CODE_SIGNING_ENV) \
 	RAUC_BUNDLE_COMPATIBLE="$(call remove_quotes,$(PTXCONF_RAUC_COMPATIBLE))" \
@@ -43,6 +57,7 @@ IMAGE_RAUC_ENV	= \
 	RAUC_BUNDLE_VERSION="$(call remove_quotes, $(PTXCONF_RAUC_BUNDLE_VERSION))" \
 	RAUC_BUNDLE_BUILD=$(call ptx/sh, date +%FT%T%z) \
 	RAUC_BUNDLE_DESCRIPTION=$(PTXCONF_IMAGE_RAUC_DESCRIPTION) \
+	$(IMAGE_RAUC_ENV_HOOK) \
 	RAUC_KEY="$(shell cs_get_uri update)" \
 	RAUC_CERT="$(shell cs_get_uri update)" \
 	RAUC_KEYRING="$(shell cs_get_ca update)" \
-- 
2.39.2