allow instances to register ubus object that should be watched

Signed-off-by: John Crispin <blogic@openwrt.org>

3 files changed, 137 insertions, 1 deletions

diff --git a/service/instance.c b/service/instance.c
index 4a45759..fa3594b 100644
--- a/service/instance.c
+++ b/service/instance.c
@@ -38,6 +38,7 @@ enum {
 	INSTANCE_ATTR_RESPAWN,
 	INSTANCE_ATTR_NICE,
 	INSTANCE_ATTR_LIMITS,
+	INSTANCE_ATTR_WATCH,
 	__INSTANCE_ATTR_MAX
 };
 
@@ -51,6 +52,7 @@ static const struct blobmsg_policy instance_attr[__INSTANCE_ATTR_MAX] = {
 	[INSTANCE_ATTR_RESPAWN] = { "respawn", BLOBMSG_TYPE_ARRAY },
 	[INSTANCE_ATTR_NICE] = { "nice", BLOBMSG_TYPE_INT32 },
 	[INSTANCE_ATTR_LIMITS] = { "limits", BLOBMSG_TYPE_TABLE },
+	[INSTANCE_ATTR_WATCH] = { "watch", BLOBMSG_TYPE_ARRAY },
 };
 
 struct instance_netdev {
@@ -414,6 +416,15 @@ instance_config_parse(struct service_instance *in)
 		trigger_add(in->trigger, in);
 	}
 
+	if (tb[INSTANCE_ATTR_WATCH]) {
+		blobmsg_for_each_attr(cur2, tb[INSTANCE_ATTR_WATCH], rem) {
+			if (blobmsg_type(cur2) != BLOBMSG_TYPE_STRING)
+				continue;
+			DEBUG(3, "watch for %s\n", blobmsg_get_string(cur2));
+			watch_add(blobmsg_get_string(cur2), in);
+		}
+	}
+
 	if ((cur = tb[INSTANCE_ATTR_NICE])) {
 		in->nice = (int8_t) blobmsg_get_u32(cur);
 		if (in->nice < -20 || in->nice > 20)
@@ -494,6 +505,7 @@ instance_free(struct service_instance *in)
 	uloop_process_delete(&in->proc);
 	uloop_timeout_cancel(&in->timeout);
 	trigger_del(in);
+	watch_del(in);
 	free(in->trigger);
 	instance_config_cleanup(in);
 	free(in->config);
diff --git a/service/trigger.c b/service/trigger.c
index 480367b..9fb77cd 100644
--- a/service/trigger.c
+++ b/service/trigger.c
@@ -323,7 +323,7 @@ void trigger_init(void)
 	q.max_running_tasks = 1;
 }
 
-void trigger_event(char *type, struct blob_attr *data)
+void trigger_event(const char *type, struct blob_attr *data)
 {
 	struct trigger *t;
 
diff --git a/service/watch.c b/service/watch.c
new file mode 100644
index 0000000..1d7cf78
--- /dev/null
+++ b/service/watch.c
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1
+ * as published by the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <libubox/blobmsg_json.h>
+
+#include "../procd.h"
+
+struct watch_object {
+	struct list_head list;
+
+	void *id;
+	char *name;
+};
+
+struct watch_subscribe {
+	struct uloop_timeout t;
+	uint32_t id;
+};
+
+static struct ubus_event_handler watch_event;
+static struct ubus_subscriber watch_subscribe;
+static LIST_HEAD(watch_objects);
+
+static void watch_subscribe_cb(struct ubus_context *ctx, struct ubus_event_handler *ev,
+		const char *type, struct blob_attr *msg)
+{
+	static const struct blobmsg_policy policy = {
+		"path", BLOBMSG_TYPE_STRING
+	};
+	struct watch_object *o;
+	struct blob_attr *attr;
+	const char *path;
+
+	DEBUG(3, "ubus event %s\n", type);
+	if (strcmp(type, "ubus.object.add") != 0)
+		return;
+
+	blobmsg_parse(&policy, 1, &attr, blob_data(msg), blob_len(msg));
+	if (!attr)
+		return;
+
+	path = blobmsg_data(attr);
+	DEBUG(3, "ubus path %s\n", path);
+
+	list_for_each_entry(o, &watch_objects, list) {
+		unsigned int id;
+
+		if (strcmp(o->name, path))
+			continue;
+		if (ubus_lookup_id(ctx, path, &id))
+			continue;
+		if (!ubus_subscribe(ctx, &watch_subscribe, id))
+			return;
+		ERROR("failed to suscribe %d\n", id);
+	}
+}
+
+void
+watch_add(const char *_name, void *id)
+{
+	int len = strlen(_name);
+	char *name;
+	struct watch_object *o = calloc_a(sizeof(*o), &name, len + 1);
+
+	o->name = name;
+	strcpy(name, _name);
+	o->id = id;
+	list_add(&o->list, &watch_objects);
+}
+
+void
+watch_del(void *id)
+{
+	struct watch_object *t, *n;
+
+	list_for_each_entry_safe(t, n, &watch_objects, list) {
+		if (t->id != id)
+			continue;
+		list_del(&t->list);
+		free(t);
+	}
+}
+
+static int
+watch_notify_cb(struct ubus_context *ctx, struct ubus_object *obj,
+		struct ubus_request_data *req, const char *method,
+		struct blob_attr *msg)
+{
+	if (1 || debug >= 3) {
+		char *str;
+
+		str = blobmsg_format_json(msg, true);
+		LOG("Received ubus notify '%s': %s\n", method, str);
+		free(str);
+	}
+
+	trigger_event(method, msg);
+	return 0;
+}
+
+void
+watch_ubus(struct ubus_context *ctx)
+{
+	watch_event.cb = watch_subscribe_cb;
+	watch_subscribe.cb = watch_notify_cb;
+	if (ubus_register_event_handler(ctx, &watch_event, "ubus.object.add"))
+		ERROR("failed to add ubus event handler\n");
+	if (ubus_register_subscriber(ctx, &watch_subscribe))
+		ERROR("failed to register ubus subscriber\n");
+}