rauc-hawkbit-updater: add support for provisioning

Read-only Oniro images now have space to provision rauc-hawkbit-updater
configuration file. The startup of the update service is conditional on
the presence of that file. The default configuration file is stored as
an example in the read-only image.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@huawei.com>

meta-oniro-core/recipes-support/rauc-hawkbit-updater/files/is-provisioned.conf

+# SPDX-FileCopyrightText: Huawei Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# Start only when a configuration file has been provided as a part
+# of the provisioning process.
+[Service]
+ConditionalPathExists=/etc/rauc-hawkbit-updater/config.conf

meta-oniro-core/recipes-support/rauc-hawkbit-updater/rauc-hawkbit-updater_%.bbappend

@@ -3,3 +3,39 @@ FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:"
 SRC_URI += " \
     file://0001-Do-not-include-glibc-specific-bits-types-struct_tm.h.patch \
     file://0001-hawkbit-client-do-not-pass-NULL-format-to-g_strdup_v.patch"
+
+# Stash the default configuration file as an example. The configuration
+# directory must be an empty mount point for persistent state. This is
+# simplistic, in a real-world-scenario we would need to have a provisioning
+# stage that populates this configuration file.
+#
+# This is the first part of the adaptation to read-only images.
+do_install:append() {
+    install -d 755 ${D}/usr/share/${PN}
+    mv ${D}${sysconfdir}/${PN}/config.conf /${D}/usr/share/${PN}/example.conf
+}
+
+inherit writables
+
+# Persist RAUC hawkbit updater configuration directory.
+WRITABLES = "rauc-hawkbit-updater-cfg"
+WRITABLE_TYPE[rauc-hawkbit-updater-cfg] = "persistent"
+WRITABLE_PATH[rauc-hawkbit-updater-cfg] = "/etc/rauc-hawkbit-updater"
+
+# Do not start the updater service unless the configuration file is present.
+#
+# This the second part of the adaptation to read-only images.
+
+FILESEXTRAPATHS:append:= "${THISDIR}/files:"
+
+SRC_URI:append = " \
+    file://is-provisioned.conf \
+    "
+
+FILES:${PN} += "\
+    ${systemd_unitdir}/system/rauc-hawkbit-updater.service.d/*.conf \
+    "
+
+do_install:append() {
+    install -D -m 644 ${WORKDIR}/is-provisioned.conf --target-directory=${D}${systemd_unitdir}/system/rauc-hawkbit-updater.service.d/
+}