package/libcamera: strip symbols before signing IPA libs

Open-Source IPA shlibs need to be signed in order to be runnable within
the same process, otherwise they are deemed Closed-Source and run in
another process and communicate over IPC.

The shlib installed on the target should be the same as the one signed
by libcamera during package creation otherwise the signature won't match
the shlib.

Buildroot sanitizes RPATH in a post build process. meson gets rid of
rpath while installing so we don't need to do it manually.

Buildroot may strip symbols, so we need to do the same before signing.

Signing the IPA shlibs is done by the meson install target, so we need
to strip the IPA shlibs, so after the build but before the install,
which a post-build hooks fits the best.

Cc: Quentin Schulz <foss+buildroot@0leil.net>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
[yann.morin.1998@free.fr: slight rewording of commit log]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/libcamera/libcamera.mk

@@ -104,4 +104,24 @@ LIBCAMERA_DEPENDENCIES += libexecinfo
 LIBCAMERA_LDFLAGS = $(TARGET_LDFLAGS) -lexecinfo
 endif
 
+# Open-Source IPA shlibs need to be signed in order to be runnable within the
+# same process, otherwise they are deemed Closed-Source and run in another
+# process and communicate over IPC.
+# Buildroot sanitizes RPATH in a post build process. meson gets rid of rpath
+# while installing so we don't need to do it manually here.
+# Buildroot may strip symbols, so we need to do the same before signing
+# otherwise the signature won't match the shlib on the rootfs. Since meson
+# install target is signing the shlibs, we need to strip them before.
+LIBCAMERA_STRIP_FIND_CMD = \
+	find $(@D)/build/src/ipa \
+	$(if $(call qstrip,$(BR2_STRIP_EXCLUDE_FILES)), \
+		-not \( $(call findfileclauses,$(call qstrip,$(BR2_STRIP_EXCLUDE_FILES))) \) ) \
+	-type f -name 'ipa_*.so' -print0
+
+define LIBCAMERA_BUILD_STRIP_IPA_SO
+	$(LIBCAMERA_STRIP_FIND_CMD) | xargs --no-run-if-empty -0 $(STRIPCMD)
+endef
+
+LIBCAMERA_POST_BUILD_HOOKS += LIBCAMERA_BUILD_STRIP_IPA_SO
+
 $(eval $(meson-package))