add functionality for registering anonymous objects as event listeners

cli.c

@@ -39,6 +39,32 @@ static int usage(char *prog)
 	return 1;
 }
 
+static int ubus_cli_listen(struct ubus_context *ctx, int argc, char **argv)
+{
+	static struct ubus_object listener;
+	const char *event;
+	int ret = 0;
+
+	if (!argc) {
+		event = "*";
+		ret = ubus_register_event_handler(ctx, &listener, NULL);
+	}
+
+	for (;argc;argv++, argc--) {
+		event = argv[0];
+		ret = ubus_register_event_handler(ctx, &listener, argv[0]);
+		if (ret)
+			break;
+	}
+
+	if (ret) {
+		fprintf(stderr, "Error while registering for event '%s': %s\n",
+			event, ubus_strerror(ret));
+	}
+
+	return 0;
+}
+
 int main(int argc, char **argv)
 {
 	static struct ubus_context *ctx;
@@ -72,7 +98,7 @@ int main(int argc, char **argv)
 		if (!ret)
 			ret = ubus_invoke(ctx, id, argv[3], NULL, receive_data, NULL);
 	} else if (!strcmp(cmd, "listen")) {
-		ret = ubus_invoke(ctx, UBUS_SYSTEM_OBJECT_EVENT, "listen", NULL, receive_data, NULL);
+		ret = ubus_cli_listen(ctx, argc - 2, argv + 2);
 	} else {
 		return usage(argv[0]);
 	}

libubus.c

@@ -27,6 +27,7 @@ const char *__ubus_strerror[__UBUS_STATUS_LAST] = {
 	[UBUS_STATUS_METHOD_NOT_FOUND] = "Method not found",
 	[UBUS_STATUS_NOT_FOUND] = "Not found",
 	[UBUS_STATUS_NO_DATA] = "No response",
+	[UBUS_STATUS_PERMISSION_DENIED] = "Permission denied",
 };
 
 static struct blob_buf b;
@@ -605,21 +606,21 @@ static bool ubus_push_object_type(struct ubus_object_type *type)
 	return true;
 }
 
-int ubus_publish(struct ubus_context *ctx, struct ubus_object *obj)
+static int __ubus_publish(struct ubus_context *ctx, struct ubus_object *obj)
 {
 	struct ubus_request req;
 	int ret;
 
-	if (obj->id || !obj->name || !obj->type)
-		return UBUS_STATUS_INVALID_ARGUMENT;
-
 	blob_buf_init(&b, 0);
-	blob_put_string(&b, UBUS_ATTR_OBJPATH, obj->name);
 
-	if (obj->type->id)
-		blob_put_int32(&b, UBUS_ATTR_OBJTYPE, obj->type->id);
-	else if (!ubus_push_object_type(obj->type))
-		return UBUS_STATUS_INVALID_ARGUMENT;
+	if (obj->name && obj->type) {
+		blob_put_string(&b, UBUS_ATTR_OBJPATH, obj->name);
+
+		if (obj->type->id)
+			blob_put_int32(&b, UBUS_ATTR_OBJTYPE, obj->type->id);
+		else if (!ubus_push_object_type(obj->type))
+			return UBUS_STATUS_INVALID_ARGUMENT;
+	}
 
 	ubus_start_request(ctx, &req, b.head, UBUS_MSG_PUBLISH, 0);
 	req.raw_data_cb = ubus_publish_cb;
@@ -634,6 +635,43 @@ int ubus_publish(struct ubus_context *ctx, struct ubus_object *obj)
 	return 0;
 }
 
+int ubus_publish(struct ubus_context *ctx, struct ubus_object *obj)
+{
+	if (!obj->name || !obj->type)
+		return UBUS_STATUS_INVALID_ARGUMENT;
+
+	return __ubus_publish(ctx, obj);
+}
+
+int ubus_register_event_handler(struct ubus_context *ctx, struct ubus_object *obj,
+				const char *pattern)
+{
+	struct blob_buf b2;
+	int ret;
+
+	if (!obj->id) {
+		if (!!obj->name ^ !!obj->type)
+			return UBUS_STATUS_INVALID_ARGUMENT;
+
+		ret = __ubus_publish(ctx, obj);
+		if (ret)
+			return ret;
+	}
+
+	/* use a second buffer, ubus_invoke() overwrites the primary one */
+	memset(&b2, 0, sizeof(b2));
+	blob_buf_init(&b2, 0);
+	blobmsg_add_u32(&b2, "object", obj->id);
+	if (pattern)
+		blobmsg_add_string(&b2, "pattern", pattern);
+
+	ret = ubus_invoke(ctx, UBUS_SYSTEM_OBJECT_EVENT, "register", b2.head,
+			  NULL, NULL);
+
+	return 0;
+}
+
+
 void ubus_default_connection_lost(struct ubus_context *ctx)
 {
 	if (ctx->sock.registered)

libubus.h

@@ -171,3 +171,7 @@ int ubus_publish(struct ubus_context *ctx, struct ubus_object *obj);
 /* send a reply to an incoming object method call */
 int ubus_send_reply(struct ubus_context *ctx, struct ubus_request_data *req,
 		    struct blob_attr *msg);
+
+/* ----------- events ----------- */
+int ubus_register_event_handler(struct ubus_context *ctx, struct ubus_object *obj,
+				const char *pattern);

ubusd_event.c

@@ -1,41 +1,140 @@
 #include "ubusd.h"
 
 static struct avl_tree patterns;
+static LIST_HEAD(catch_all);
 static struct ubus_object *event_obj;
 
-struct event_pattern {
-	struct avl_node avl;
+enum evs_type {
+	EVS_PATTERN,
+	EVS_CATCHALL
+};
 
+struct event_source {
+	struct list_head list;
 	struct ubus_object *obj;
+	enum evs_type type;
+	union {
+		struct {
+			struct avl_node avl;
+		} pattern;
+		struct {
+			struct list_head list;
+		} catchall;
+	};
+};
+
+struct event_pattern {
+	struct event_source evs;
 	struct list_head list;
+};
+
+struct event_catchall {
+	struct event_source evs;
 
-	const char *path;
+	struct list_head list;
+	struct ubus_object *obj;
 };
 
-static void ubusd_delete_event_pattern(struct event_pattern *ev)
+static void ubusd_delete_event_source(struct event_source *evs)
 {
-	list_del(&ev->list);
-	avl_delete(&patterns, &ev->avl);
-	free(ev);
+	list_del(&evs->list);
+	switch (evs->type) {
+	case EVS_PATTERN:
+		avl_delete(&patterns, &evs->pattern.avl);
+		break;
+	case EVS_CATCHALL:
+		list_del(&evs->catchall.list);
+		break;
+	}
+	free(evs);
 }
 
 void ubusd_event_cleanup_object(struct ubus_object *obj)
 {
-	struct event_pattern *ev;
+	struct event_source *ev;
 
-	while (!list_empty(&obj->event_patterns)) {
-		ev = list_first_entry(&obj->event_patterns,
-				      struct event_pattern, list);
-		ubusd_delete_event_pattern(ev);
+	while (!list_empty(&obj->events)) {
+		ev = list_first_entry(&obj->events, struct event_source, list);
+		ubusd_delete_event_source(ev);
 	}
 }
 
-static int ubusd_event_recv(struct ubus_client *cl, const char *method, struct blob_attr *msg)
+enum {
+	EVMSG_PATTERN,
+	EVMSG_OBJECT,
+	EVMSG_LAST,
+};
+
+static struct blobmsg_policy ev_policy[] = {
+	[EVMSG_PATTERN] = { .name = "pattern", .type = BLOBMSG_TYPE_STRING },
+	[EVMSG_OBJECT] = { .name = "object", .type = BLOBMSG_TYPE_INT32 },
+};
+
+
+static struct event_source *ubusd_alloc_event_source(struct ubus_object *obj, enum evs_type type, int datalen)
+{
+	struct event_source *evs;
+
+	evs = calloc(1, sizeof(*evs) + datalen);
+	list_add(&evs->list, &obj->events);
+	evs->obj = obj;
+	evs->type = type;
+	return evs;
+}
+
+static int ubusd_alloc_catchall(struct ubus_object *obj)
+{
+	struct event_source *evs;
+
+	evs = ubusd_alloc_event_source(obj, EVS_CATCHALL, 0);
+	list_add(&evs->catchall.list, &catch_all);
+
+	return 0;
+}
+
+static int ubusd_alloc_event_pattern(struct ubus_client *cl, struct blob_attr *msg)
 {
-	fprintf(stderr, "event: call to method '%s'\n", method);
+	struct event_source *ev;
+	struct ubus_object *obj;
+	struct blob_attr *attr[EVMSG_LAST];
+	const char *pattern;
+	uint32_t id;
+
+	blobmsg_parse(ev_policy, EVMSG_LAST, attr, blob_data(msg), blob_len(msg));
+	if (!attr[EVMSG_OBJECT])
+		return UBUS_STATUS_INVALID_ARGUMENT;
+
+	id = blobmsg_get_u32(attr[EVMSG_OBJECT]);
+	if (id < UBUS_SYSTEM_OBJECT_MAX)
+		return UBUS_STATUS_PERMISSION_DENIED;
+
+	obj = ubusd_find_object(id);
+	if (!obj)
+		return UBUS_STATUS_NOT_FOUND;
+
+	if (obj->client != cl)
+		return UBUS_STATUS_PERMISSION_DENIED;
+
+	if (!attr[EVMSG_PATTERN])
+		return ubusd_alloc_catchall(obj);
+
+	pattern = blobmsg_data(attr[EVMSG_PATTERN]);
+	ev = ubusd_alloc_event_source(obj, EVS_PATTERN, strlen(pattern) + 1);
+	ev->pattern.avl.key = (void *) (ev + 1);
+	strcpy(ev->pattern.avl.key, pattern);
+	avl_insert(&patterns, &ev->pattern.avl);
+
 	return 0;
 }
 
+static int ubusd_event_recv(struct ubus_client *cl, const char *method, struct blob_attr *msg)
+{
+	if (!strcmp(method, "register"))
+		return ubusd_alloc_event_pattern(cl, msg);
+
+	return UBUS_STATUS_INVALID_COMMAND;
+}
+
 void ubusd_event_init(void)
 {
 	ubus_init_string_tree(&patterns, true);

ubusd_obj.c

@@ -118,11 +118,12 @@ struct ubus_object *ubusd_create_object(struct ubus_client *cl, struct blob_attr
 	else if (attr[UBUS_ATTR_SIGNATURE])
 		type = ubus_create_obj_type(attr[UBUS_ATTR_SIGNATURE]);
 
-	if (!type)
+	if (!!type ^ !!attr[UBUS_ATTR_OBJPATH])
 		return NULL;
 
 	obj = ubusd_create_object_internal(type, 0);
-	ubus_unref_object_type(type);
+	if (type)
+		ubus_unref_object_type(type);
 
 	if (!obj)
 		return NULL;
@@ -141,6 +142,8 @@ struct ubus_object *ubusd_create_object(struct ubus_client *cl, struct blob_attr
 
 	obj->client = cl;
 	list_add(&obj->list, &cl->objects);
+	INIT_LIST_HEAD(&obj->events);
+
 	return obj;
 
 free:
@@ -150,6 +153,7 @@ free:
 
 void ubusd_free_object(struct ubus_object *obj)
 {
+	ubusd_event_cleanup_object(obj);
 	if (obj->path.key) {
 		avl_delete(&path, &obj->path);
 		free(obj->path.key);

ubusd_obj.h

@@ -26,7 +26,7 @@ struct ubus_object {
 	struct ubus_id id;
 	struct list_head list;
 
-	struct list_head event_patterns;
+	struct list_head events;
 
 	struct ubus_object_type *type;
 	struct avl_node path;
@@ -39,4 +39,17 @@ struct ubus_object *ubusd_create_object(struct ubus_client *cl, struct blob_attr
 struct ubus_object *ubusd_create_object_internal(struct ubus_object_type *type, uint32_t id);
 void ubusd_free_object(struct ubus_object *obj);
 
+static inline struct ubus_object *ubusd_find_object(uint32_t objid)
+{
+	struct ubus_object *obj;
+	struct ubus_id *id;
+
+	id = ubus_find_id(&objects, objid);
+	if (!id)
+		return NULL;
+
+	obj = container_of(id, struct ubus_object, id);
+	return obj;
+}
+
 #endif

ubusd_proto.c

@@ -203,18 +203,16 @@ static int ubusd_handle_invoke(struct ubus_client *cl, struct ubus_msg_buf *ub,
 static int ubusd_handle_response(struct ubus_client *cl, struct ubus_msg_buf *ub, struct blob_attr **attr)
 {
 	struct ubus_object *obj;
-	struct ubus_id *id;
 
 	if (!attr[UBUS_ATTR_OBJID] ||
 	    (ub->hdr.type == UBUS_MSG_STATUS && !attr[UBUS_ATTR_STATUS]) ||
 	    (ub->hdr.type == UBUS_MSG_DATA && !attr[UBUS_ATTR_DATA]))
 		goto error;
 
-	id = ubus_find_id(&objects, blob_get_int32(attr[UBUS_ATTR_OBJID]));
-	if (!id)
+	obj = ubusd_find_object(blob_get_int32(attr[UBUS_ATTR_OBJID]));
+	if (!obj)
 		goto error;
 
-	obj = container_of(id, struct ubus_object, id);
 	if (cl != obj->client)
 		goto error;
 

ubusmsg.h

@@ -70,6 +70,7 @@ enum ubus_msg_status {
 	UBUS_STATUS_METHOD_NOT_FOUND,
 	UBUS_STATUS_NOT_FOUND,
 	UBUS_STATUS_NO_DATA,
+	UBUS_STATUS_PERMISSION_DENIED,
 	__UBUS_STATUS_LAST
 };