Fix: relayd live don't send incomplete stream list

[lttng-tools.git] / src / bin / lttng-relayd / live.c

diff --git a/src/bin/lttng-relayd/live.c b/src/bin/lttng-relayd/live.c
index cacad2916f281d7589f3324b536d1ecef4853419..888ec2d4f616d10f5d4720bfbea05158361d48bf 100644 (file)
--- a/src/bin/lttng-relayd/live.c
+++ b/src/bin/lttng-relayd/live.c
@@ -267,7 +267,7 @@ end_unlock:
 static
 int make_viewer_streams(struct relay_session *session,
                enum lttng_viewer_seek seek_t, uint32_t *nb_total, uint32_t *nb_unsent,
-               uint32_t *nb_created)
+               uint32_t *nb_created, bool *closed)
 {
        int ret;
        struct lttng_ht_iter iter;
@@ -281,6 +281,10 @@ int make_viewer_streams(struct relay_session *session,
         */
        pthread_mutex_lock(&session->lock);
 
+       if (session->connection_closed) {
+               *closed = true;
+       }
+
        /*
         * Create viewer streams for relay streams that are ready to be
         * used for a the given session id only.
@@ -862,6 +866,7 @@ int viewer_get_new_streams(struct relay_connection *conn)
        struct lttng_viewer_new_streams_response response;
        struct relay_session *session;
        uint64_t session_id;
+       bool closed = false;
 
        assert(conn);
 
@@ -897,7 +902,7 @@ int viewer_get_new_streams(struct relay_connection *conn)
        response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 
        ret = make_viewer_streams(session, LTTNG_VIEWER_SEEK_LAST, &nb_total, &nb_unsent,
-                       &nb_created);
+                       &nb_created, &closed);
        if (ret < 0) {
                goto end_put_session;
        }
@@ -906,12 +911,11 @@ int viewer_get_new_streams(struct relay_connection *conn)
        response.streams_count = htobe32(nb_streams);
 
        /*
-        * If the session is closed and we have no new streams to send,
-        * it means that the viewer has already received the whole trace
-        * for this session and should now close it.
+        * If the session is closed, HUP when there are no more streams.
         */
-       if (nb_total == 0 && session->connection_closed) {
+       if (closed && nb_total == 0) {
                send_streams = 0;
+               response.streams_count = 0;
                response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
                goto send_reply;
        }
@@ -964,6 +968,7 @@ int viewer_attach_session(struct relay_connection *conn)
        struct lttng_viewer_attach_session_request request;
        struct lttng_viewer_attach_session_response response;
        struct relay_session *session = NULL;
+       bool closed = false;
 
        assert(conn);
 
@@ -1022,12 +1027,26 @@ int viewer_attach_session(struct relay_connection *conn)
                goto send_reply;
        }
 
-       ret = make_viewer_streams(session, seek_type, &nb_streams, NULL, NULL);
+       ret = make_viewer_streams(session, seek_type, &nb_streams, NULL,
+                       NULL, &closed);
        if (ret < 0) {
                goto end_put_session;
        }
        response.streams_count = htobe32(nb_streams);
 
+       /*
+        * If the session is closed when the viewer is attaching, it
+        * means some of the streams may have been concurrently removed,
+        * so we don't allow the viewer to attach, even if there are
+        * streams available.
+        */
+       if (closed) {
+               send_streams = 0;
+               response.streams_count = 0;
+               response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
+               goto send_reply;
+       }
+
 send_reply:
        health_code_update();
        ret = send_response(conn->sock, &response, sizeof(response));