Fix: race with the viewer and readiness of streams

[lttng-tools.git] / src / bin / lttng-sessiond / kernel-consumer.c

diff --git a/src/bin/lttng-sessiond/kernel-consumer.c b/src/bin/lttng-sessiond/kernel-consumer.c
index 70759fb36d90149d8964967d3b20608c60bcc9ff..4c069588a36cf36ce8755433f2f03c480df06ba4 100644 (file)
--- a/src/bin/lttng-sessiond/kernel-consumer.c
+++ b/src/bin/lttng-sessiond/kernel-consumer.c
@@ -262,6 +262,40 @@ error:
        return ret;
 }
 
+/*
+ * Sending the notification that all streams were sent with STREAMS_SENT.
+ */
+int kernel_consumer_streams_sent(struct consumer_socket *sock,
+               struct ltt_kernel_session *session, uint64_t channel_key)
+{
+       int ret;
+       struct lttcomm_consumer_msg lkm;
+       struct consumer_output *consumer;
+
+       assert(sock);
+       assert(session);
+
+       DBG("Sending streams_sent");
+       /* Get consumer output pointer */
+       consumer = session->consumer;
+
+       /* Prep stream consumer message */
+       consumer_init_streams_sent_comm_msg(&lkm,
+                       LTTNG_CONSUMER_STREAMS_SENT,
+                       channel_key, consumer->net_seq_index);
+
+       health_code_update();
+
+       /* Send stream and file descriptor */
+       ret = consumer_send_msg(sock, &lkm);
+       if (ret < 0) {
+               goto error;
+       }
+
+error:
+       return ret;
+}
+
 /*
  * Send all stream fds of kernel channel to the consumer.
  */
@@ -271,6 +305,7 @@ int kernel_consumer_send_channel_stream(struct consumer_socket *sock,
 {
        int ret;
        struct ltt_kernel_stream *stream;
+       uint64_t channel_key = -1ULL;
 
        /* Safety net */
        assert(channel);
@@ -304,8 +339,22 @@ int kernel_consumer_send_channel_stream(struct consumer_socket *sock,
                if (ret < 0) {
                        goto error;
                }
+               if (channel_key == -1ULL) {
+                       channel_key = channel->fd;
+               }
+       }
+
+       if (!monitor || channel_key == -1ULL) {
+               goto end;
+       }
+
+       /* Add stream on the kernel consumer side. */
+       ret = kernel_consumer_streams_sent(sock, session, channel_key);
+       if (ret < 0) {
+               goto error;
        }
 
+end:
 error:
        return ret;
 }