X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fust-app.c;h=8f7db8f2ccbda06e5584a93f332576b70a62b9a9;hb=4f3ab6ee347964379eefc57f41f8a381965b4316;hp=7da843a9e0a1d1bb56ba896e8283d28fec301358;hpb=3d8ca23bff823eab12128dfbb494369c15f31403;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index 7da843a9e..8f7db8f2c 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -721,9 +721,9 @@ error:
 }
 
 /*
- * Create stream onto the UST tracer for a UST session.
+ * Create metadata stream onto the UST tracer for a given session.
  */
-static int create_ust_stream(struct ust_app *app,
+static int create_ust_metadata_stream(struct ust_app *app,
 		struct ust_app_session *ua_sess)
 {
 	int ret;
@@ -748,6 +748,52 @@ error:
 	return ret;
 }
 
+/*
+ * Create stream onto the UST tracer for a given channel.
+ *
+ * Return -ENOENT if no more stream is available for this channel.
+ * On success, return 0.
+ * On error, return a negative value.
+ */
+static int create_ust_stream(struct ust_app *app,
+		struct ust_app_channel *ua_chan, struct ltt_ust_stream *stream)
+{
+	int ret;
+
+	assert(app);
+	assert(ua_chan);
+	assert(ua_chan->obj);
+	assert(stream);
+
+	health_code_update(&health_thread_cmd);
+
+	/* We are going to receive 2 fds, we need to reserve them. */
+	ret = lttng_fd_get(LTTNG_FD_APPS, 2);
+	if (ret < 0) {
+		ERR("Exhausted number of available FD on stream creation");
+		/* Just to make sure we never return -ENOENT. */
+		ret = -1;
+		goto error;
+	}
+
+	ret = ustctl_create_stream(app->sock, ua_chan->obj, &stream->obj);
+	if (ret < 0) {
+		lttng_fd_put(LTTNG_FD_APPS, 2);
+		/* Indicates that there is no more stream for that channel. */
+		if (ret != -ENOENT) {
+			ERR("UST create metadata stream failed (ret: %d)", ret);
+		}
+		goto error;
+	}
+
+	/* Set stream handle with the returned value. */
+	stream->handle = stream->obj->handle;
+
+error:
+	health_code_update(&health_thread_cmd);
+	return ret;
+}
+
 /*
  * Create the specified channel onto the UST tracer for a UST session.
  */
@@ -1375,7 +1421,7 @@ static int create_ust_app_metadata(struct ust_app_session *ua_sess,
 
 	/* Open UST metadata stream */
 	if (ua_sess->metadata->stream_obj == NULL) {
-		ret = create_ust_stream(app, ua_sess);
+		ret = create_ust_metadata_stream(app, ua_sess);
 		if (ret < 0) {
 			goto error;
 		}
@@ -2307,26 +2353,20 @@ int ust_app_start_trace(struct ltt_ust_session *usess, struct ust_app *app)
 				goto error_rcu_unlock;
 			}
 
-			/* We are going to receive 2 fds, we need to reserve them. */
-			ret = lttng_fd_get(LTTNG_FD_APPS, 2);
-			if (ret < 0) {
-				ERR("Exhausted number of available FD upon stream create");
-				free(ustream);
-				goto error_rcu_unlock;
-			}
-
 			health_code_update(&health_thread_cmd);
 
-			ret = ustctl_create_stream(app->sock, ua_chan->obj,
-					&ustream->obj);
+			ret = create_ust_stream(app, ua_chan, ustream);
 			if (ret < 0) {
-				/* Got all streams */
-				lttng_fd_put(LTTNG_FD_APPS, 2);
+				/* Free unused memory after this point. */
 				free(ustream);
+				if (ret == -ENOENT) {
+					/* Got all streams. Continue normal execution. */
+					break;
+				}
+				/* Error at this point. Stop everything. */
 				ret = LTTNG_ERR_UST_STREAM_FAIL;
-				break;
+				goto error_rcu_unlock;
 			}
-			ustream->handle = ustream->obj->handle;
 
 			health_code_update(&health_thread_cmd);