[LEDE-DEV] [PATCH 3/3] ubusd: move global retmsg per client

[Alexandru Ardelean]

Even with the tx_queue-ing issue resolved, what
seems to happen afterwards, is that all the messages
seems to get through, but the client still loops
in the `ubus_complete_request()` waiting for
`req->status_msg` or for a timeout.

Though, the timeout does not seem to happen, because
the data is processed in `ubus_poll_data()`, with
a infinite poll() timeout (ubus_complete_request() is
called with timeout 0).

It's likely that either the `seq` or `peer` sent from
ubusd are wrong, and the client cannot get the correct
ubus request in `ubus_process_req_msg()`.
I haven't digged too deep into this ; setting the
`retmsg` object on the client struct seems to have
resolved any hanging with the `ubus list` command.

Signed-off-by: Alexandru Ardelean <ardeleanalex at gmail.com>
---
 ubusd.h       |  2 ++
 ubusd_proto.c | 35 +++++++++++++++++++++++------------
 2 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/ubusd.h b/ubusd.h
index 6748c65..a9dd04e 100644
--- a/ubusd.h
+++ b/ubusd.h
@@ -39,6 +39,7 @@ struct ubus_msg_buf {
 struct ubus_client {
 	struct ubus_id id;
 	struct uloop_fd sock;
+	struct blob_buf b;
 
 	uid_t uid;
 	gid_t gid;
@@ -57,6 +58,7 @@ struct ubus_client {
 		struct ubus_msghdr hdr;
 		struct blob_attr data;
 	} hdrbuf;
+	struct ubus_msg_buf *retmsg;
 };
 
 struct ubus_path {
diff --git a/ubusd_proto.c b/ubusd_proto.c
index 631047b..d71f74e 100644
--- a/ubusd_proto.c
+++ b/ubusd_proto.c
@@ -17,8 +17,6 @@
 #include "ubusd.h"
 
 struct blob_buf b;
-static struct ubus_msg_buf *retmsg;
-static int *retmsg_data;
 static struct avl_tree clients;
 
 static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
@@ -444,6 +442,8 @@ void ubusd_proto_receive_message(struct ubus_client *cl, struct ubus_msg_buf *ub
 {
 	ubus_cmd_cb cb = NULL;
 	int ret;
+	struct ubus_msg_buf *retmsg = cl->retmsg;
+	int *retmsg_data = blob_data(blob_data(retmsg->data));
 
 	retmsg->hdr.seq = ub->hdr.seq;
 	retmsg->hdr.peer = ub->hdr.peer;
@@ -468,6 +468,22 @@ void ubusd_proto_receive_message(struct ubus_client *cl, struct ubus_msg_buf *ub
 	ubus_msg_send(cl, retmsg, false);
 }
 
+static int ubusd_proto_init_retmsg(struct ubus_client *cl)
+{
+	struct blob_buf *b = &cl->b;
+
+	blob_buf_init(&cl->b, 0);
+	blob_put_int32(&cl->b, UBUS_ATTR_STATUS, 0);
+
+	/* we make the 'retmsg' buffer shared with the blob_buf b, to reduce mem duplication */
+	cl->retmsg = ubus_msg_new(b->head, blob_raw_len(b->head), true);
+	if (!cl->retmsg)
+		return -1;
+
+	cl->retmsg->hdr.type = UBUS_MSG_STATUS;
+	return 0;
+}
+
 struct ubus_client *ubusd_proto_new_client(int fd, uloop_fd_handler cb)
 {
 	struct ubus_client *cl;
@@ -488,6 +504,9 @@ struct ubus_client *ubusd_proto_new_client(int fd, uloop_fd_handler cb)
 	if (!ubus_alloc_id(&clients, &cl->id, 0))
 		goto free;
 
+	if (ubusd_proto_init_retmsg(cl))
+		goto free;
+
 	if (!ubusd_send_hello(cl))
 		goto delete;
 
@@ -508,6 +527,8 @@ void ubusd_proto_free_client(struct ubus_client *cl)
 		obj = list_first_entry(&cl->objects, struct ubus_object, list);
 		ubusd_free_object(obj);
 	}
+	ubus_msg_free(cl->retmsg);
+	blob_buf_free(&cl->b);
 
 	ubusd_acl_free_client(cl);
 	ubus_free_id(&clients, &cl->id);
@@ -550,14 +571,4 @@ void ubus_notify_unsubscribe(struct ubus_subscription *s)
 static void __constructor ubusd_proto_init(void)
 {
 	ubus_init_id_tree(&clients);
-
-	blob_buf_init(&b, 0);
-	blob_put_int32(&b, UBUS_ATTR_STATUS, 0);
-
-	retmsg = ubus_msg_from_blob(false);
-	if (!retmsg)
-		exit(1);
-
-	retmsg->hdr.type = UBUS_MSG_STATUS;
-	retmsg_data = blob_data(blob_data(retmsg->data));
 }
-- 
2.7.4