X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fust-app.c;h=374360e48c365937a20952e6623e356e21fae41c;hp=7da843a9e0a1d1bb56ba896e8283d28fec301358;hb=7f13370536e1ad64db733423b542755c97160f4d;hpb=3d8ca23bff823eab12128dfbb494369c15f31403

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index 7da843a9e..374360e48 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;
@@ -739,6 +739,7 @@ static int create_ust_stream(struct ust_app *app,
 	ret = ustctl_create_stream(app->sock, ua_sess->metadata->obj,
 			&ua_sess->metadata->stream_obj);
 	if (ret < 0) {
+		lttng_fd_put(LTTNG_FD_APPS, 2);
 		ERR("UST create metadata stream failed");
 		goto error;
 	}
@@ -748,6 +749,66 @@ 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;
+	}
+
+	/*
+	 * Set the stream name before creating it. On error, we don't have to
+	 * delete it on the tracer side.
+	 */
+	ret = snprintf(stream->name, sizeof(stream->name), "%s_%u",
+			ua_chan->name, ua_chan->streams.count);
+	if (ret < 0) {
+		/* Without the stream name we can't continue using it. */
+		PERROR("snprintf UST create stream");
+		/* 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 != -LTTNG_UST_ERR_NOENT) {
+			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 +1436,7 @@ 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;
 		}
@@ -2307,42 +2368,27 @@ 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 == -LTTNG_UST_ERR_NOENT) {
+					/* 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);
 
-			/* Order is important */
+			/* Order is important this is why a list is used. */
 			cds_list_add_tail(&ustream->list, &ua_chan->streams.head);
-			ret = snprintf(ustream->name, sizeof(ustream->name), "%s_%u",
-					ua_chan->name, ua_chan->streams.count);
 			ua_chan->streams.count++;
-			if (ret < 0) {
-				PERROR("asprintf UST create stream");
-				/*
-				 * XXX what should we do here with the
-				 * stream ?
-				 */
-				continue;
-			}
+
 			DBG2("UST stream %d ready (handle: %d)", ua_chan->streams.count,
 					ustream->handle);
 		}