libubus: implement notify handling

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

libubus-io.c

@@ -35,6 +35,7 @@ static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {
 	[UBUS_ATTR_METHOD] = { .type = BLOB_ATTR_STRING },
 	[UBUS_ATTR_ACTIVE] = { .type = BLOB_ATTR_INT8 },
 	[UBUS_ATTR_NO_REPLY] = { .type = BLOB_ATTR_INT8 },
+	[UBUS_ATTR_SUBSCRIBERS] = { .type = BLOB_ATTR_NESTED },
 };
 
 static struct blob_attr *attrbuf[UBUS_ATTR_MAX];

libubus-req.c

@@ -227,6 +227,70 @@ int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
 	return ubus_complete_request(ctx, &req, timeout);
 }
 
+static void
+ubus_notify_complete_cb(struct ubus_request *req, int ret)
+{
+	struct ubus_notify_request *nreq;
+
+	nreq = container_of(req, struct ubus_notify_request, req);
+	if (!nreq->complete_cb)
+		return;
+
+	nreq->complete_cb(nreq, 0, 0);
+}
+
+static int
+__ubus_notify_async(struct ubus_context *ctx, struct ubus_object *obj,
+		    const char *type, struct blob_attr *msg,
+		    struct ubus_notify_request *req, bool reply)
+{
+	memset(req, 0, sizeof(*req));
+
+	blob_buf_init(&b, 0);
+	blob_put_int32(&b, UBUS_ATTR_OBJID, obj->id);
+	blob_put_string(&b, UBUS_ATTR_METHOD, type);
+
+	if (!reply)
+		blob_put_int8(&b, UBUS_ATTR_NO_REPLY, true);
+
+	if (msg)
+		blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
+
+	if (ubus_start_request(ctx, &req->req, b.head, UBUS_MSG_NOTIFY, obj->id) < 0)
+		return UBUS_STATUS_INVALID_ARGUMENT;
+
+	/* wait for status message from ubusd first */
+	req->req.notify = true;
+	req->pending = 1;
+	req->id[0] = obj->id;
+	req->req.complete_cb = ubus_notify_complete_cb;
+
+	return 0;
+}
+
+int ubus_notify_async(struct ubus_context *ctx, struct ubus_object *obj,
+		      const char *type, struct blob_attr *msg,
+		      struct ubus_notify_request *req)
+{
+	return __ubus_notify_async(ctx, obj, type, msg, req, true);
+}
+
+int ubus_notify(struct ubus_context *ctx, struct ubus_object *obj,
+		const char *type, struct blob_attr *msg, int timeout)
+{
+	struct ubus_notify_request req;
+	int ret;
+
+	ret = __ubus_notify_async(ctx, obj, type, msg, &req, timeout >= 0);
+	if (ret < 0)
+		return ret;
+
+	if (timeout < 0)
+		return 0;
+
+	return ubus_complete_request(ctx, &req.req, timeout);
+}
+
 static bool ubus_get_status(struct ubus_msghdr *hdr, int *ret)
 {
 	struct blob_attr **attrbuf = ubus_parse_msg(hdr->data);
@@ -278,13 +342,43 @@ ubus_process_req_data(struct ubus_request *req, struct ubus_msghdr *hdr)
 	list_add(&data->list, &req->pending);
 }
 
+static int
+ubus_find_notify_id(struct ubus_notify_request *n, uint32_t objid)
+{
+	uint32_t pending = n->pending;
+	int i;
+
+	for (i = 0; pending; i++, pending >>= 1) {
+		if (!(pending & 1))
+			continue;
+
+		if (n->id[i] == objid)
+			return i;
+	}
+
+	return -1;
+}
+
 static struct ubus_request *
-ubus_find_request(struct ubus_context *ctx, uint32_t seq, uint32_t peer)
+ubus_find_request(struct ubus_context *ctx, uint32_t seq, uint32_t peer, int *id)
 {
 	struct ubus_request *req;
 
 	list_for_each_entry(req, &ctx->requests, list) {
-		if (seq != req->seq || peer != req->peer)
+		struct ubus_notify_request *nreq;
+		nreq = container_of(req, struct ubus_notify_request, req);
+
+		if (seq != req->seq)
+			continue;
+
+		if (req->notify) {
+			if (!nreq->pending)
+				continue;
+
+			*id = ubus_find_notify_id(nreq, peer);
+			if (*id < 0)
+				continue;
+		} else if (peer != req->peer)
 			continue;
 
 		return req;
@@ -292,21 +386,62 @@ ubus_find_request(struct ubus_context *ctx, uint32_t seq, uint32_t peer)
 	return NULL;
 }
 
+static void ubus_process_notify_status(struct ubus_request *req, int id, struct ubus_msghdr *hdr)
+{
+	struct ubus_notify_request *nreq;
+	struct blob_attr **tb;
+	struct blob_attr *cur;
+	int rem, idx = 1;
+	int ret;
+
+	nreq = container_of(req, struct ubus_notify_request, req);
+	nreq->pending &= ~(1 << id);
+
+	if (!id) {
+		/* first id: ubusd's status message with a list of ids */
+		tb = ubus_parse_msg(hdr->data);
+		if (tb[UBUS_ATTR_SUBSCRIBERS]) {
+			blob_for_each_attr(cur, tb[UBUS_ATTR_SUBSCRIBERS], rem) {
+				if (!blob_check_type(blob_data(cur), blob_len(cur), BLOB_ATTR_INT32))
+					continue;
+
+				nreq->pending |= (1 << idx);
+				nreq->id[idx] = blob_get_int32(cur);
+				idx++;
+
+				if (idx == UBUS_MAX_NOTIFY_PEERS + 1)
+					break;
+			}
+		}
+	} else {
+		ubus_get_status(hdr, &ret);
+		if (nreq->status_cb)
+			nreq->status_cb(nreq, id, ret);
+	}
+
+	if (!nreq->pending)
+		ubus_set_req_status(req, 0);
+}
+
 void __hidden ubus_process_req_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 {
 	struct ubus_request *req;
+	int id = -1;
 
 	switch(hdr->type) {
 	case UBUS_MSG_STATUS:
-		req = ubus_find_request(ctx, hdr->seq, hdr->peer);
+		req = ubus_find_request(ctx, hdr->seq, hdr->peer, &id);
 		if (!req)
 			break;
 
-		ubus_process_req_status(req, hdr);
+		if (id >= 0)
+			ubus_process_notify_status(req, id, hdr);
+		else
+			ubus_process_req_status(req, hdr);
 		break;
 
 	case UBUS_MSG_DATA:
-		req = ubus_find_request(ctx, hdr->seq, hdr->peer);
+		req = ubus_find_request(ctx, hdr->seq, hdr->peer, &id);
 		if (req && (req->data_cb || req->raw_data_cb))
 			ubus_process_req_data(req, hdr);
 		break;

libubus.c

@@ -108,9 +108,10 @@ ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 
 void __hidden ubus_process_pending_msg(struct ubus_context *ctx)
 {
-	struct ubus_pending_msg *pending, *tmp;
+	struct ubus_pending_msg *pending;
 
-	list_for_each_entry_safe(pending, tmp, &ctx->pending, list) {
+	while (!list_empty(&ctx->pending)) {
+		pending = list_first_entry(&ctx->pending, struct ubus_pending_msg, list);
 		list_del(&pending->list);
 		ubus_process_msg(ctx, &pending->hdr);
 		free(pending);

libubus.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2011-2012 Felix Fietkau <nbd@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
@@ -22,6 +22,8 @@
 #include "ubusmsg.h"
 #include "ubus_common.h"
 
+#define UBUS_MAX_NOTIFY_PEERS	16
+
 struct ubus_context;
 struct ubus_msg_src;
 struct ubus_object;
@@ -30,6 +32,7 @@ struct ubus_request_data;
 struct ubus_object_data;
 struct ubus_event_handler;
 struct ubus_subscriber;
+struct ubus_notify_request;
 
 typedef void (*ubus_lookup_handler_t)(struct ubus_context *ctx,
 				      struct ubus_object_data *obj,
@@ -45,6 +48,8 @@ typedef void (*ubus_event_handler_t)(struct ubus_context *ctx, struct ubus_event
 typedef void (*ubus_data_handler_t)(struct ubus_request *req,
 				    int type, struct blob_attr *msg);
 typedef void (*ubus_complete_handler_t)(struct ubus_request *req, int ret);
+typedef void (*ubus_notify_complete_handler_t)(struct ubus_notify_request *req,
+					       int idx, int ret);
 
 #define UBUS_OBJECT_TYPE(_name, _methods)		\
 	{						\
@@ -138,17 +143,17 @@ struct ubus_request_data {
 	uint32_t peer;
 	uint32_t seq;
 	bool deferred;
-	bool notify;
 };
 
 struct ubus_request {
 	struct list_head list;
 
 	struct list_head pending;
-	bool status_msg;
 	int status_code;
+	bool status_msg;
 	bool blocked;
 	bool cancelled;
+	bool notify;
 
 	uint32_t peer;
 	uint32_t seq;
@@ -161,6 +166,15 @@ struct ubus_request {
 	void *priv;
 };
 
+struct ubus_notify_request {
+	struct ubus_request req;
+
+	ubus_notify_complete_handler_t status_cb;
+	ubus_notify_complete_handler_t complete_cb;
+
+	uint32_t pending;
+	uint32_t id[UBUS_MAX_NOTIFY_PEERS + 1];
+};
 
 struct ubus_context *ubus_connect(const char *path);
 int ubus_reconnect(struct ubus_context *ctx, const char *path);
@@ -236,6 +250,18 @@ static inline void ubus_defer_request(struct ubus_context *ctx,
 void ubus_complete_deferred_request(struct ubus_context *ctx,
 				    struct ubus_request_data *req, int ret);
 
+/*
+ * send a notification to all subscribers of an object
+ * if timeout < 0, no reply is expected from subscribers
+ */
+int ubus_notify(struct ubus_context *ctx, struct ubus_object *obj,
+		const char *type, struct blob_attr *msg, int timeout);
+
+int ubus_notify_async(struct ubus_context *ctx, struct ubus_object *obj,
+		      const char *type, struct blob_attr *msg,
+		      struct ubus_notify_request *req);
+
+
 /* ----------- events ----------- */
 
 int ubus_send_event(struct ubus_context *ctx, const char *id,