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=dd8d103fd1d9c2773fe9f032d1389cedd09f32d3;hb=7f13370536e1ad64db733423b542755c97160f4d;hpb=c617c0c651432f9d5ae7adf4c5c1a5fd92ad828e

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index dd8d103fd..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.
  */
@@ -1030,16 +1091,27 @@ error:
 }
 
 /*
- * Create a UST session onto the tracer of app and add it the session
- * hashtable.
+ * Create a session on the tracer side for the given app.
+ *
+ * On success, ua_sess_ptr is populated with the session pointer or else left
+ * untouched. If the session was created, is_created is set to 1. On error,
+ * it's left untouched. Note that ua_sess_ptr is mandatory but is_created can
+ * be NULL.
  *
- * Return ust app session or NULL on error.
+ * Returns 0 on success or else a negative code which is either -ENOMEM or
+ * -ENOTCONN which is the default code if the ustctl_create_session fails.
  */
-static struct ust_app_session *create_ust_app_session(
-		struct ltt_ust_session *usess, struct ust_app *app)
+static int create_ust_app_session(struct ltt_ust_session *usess,
+		struct ust_app *app, struct ust_app_session **ua_sess_ptr,
+		int *is_created)
 {
+	int ret, created = 0;
 	struct ust_app_session *ua_sess;
 
+	assert(usess);
+	assert(app);
+	assert(ua_sess_ptr);
+
 	health_code_update(&health_thread_cmd);
 
 	ua_sess = lookup_session_by_app(usess, app);
@@ -1049,23 +1121,28 @@ static struct ust_app_session *create_ust_app_session(
 		ua_sess = alloc_ust_app_session();
 		if (ua_sess == NULL) {
 			/* Only malloc can failed so something is really wrong */
-			goto end;
+			ret = -ENOMEM;
+			goto error;
 		}
 		shadow_copy_session(ua_sess, usess, app);
+		created = 1;
 	}
 
 	health_code_update(&health_thread_cmd);
 
 	if (ua_sess->handle == -1) {
-		int ret;
-
 		ret = ustctl_create_session(app->sock);
 		if (ret < 0) {
 			ERR("Creating session for app pid %d", app->pid);
 			delete_ust_app_session(-1, ua_sess);
-			/* This means that the tracer is gone... */
-			ua_sess = (void*) -1UL;
-			goto end;
+			if (ret != -ENOMEM) {
+				/*
+				 * Tracer is probably gone or got an internal error so let's
+				 * behave like it will soon unregister or not usable.
+				 */
+				ret = -ENOTCONN;
+			}
+			goto error;
 		}
 
 		ua_sess->handle = ret;
@@ -1077,9 +1154,16 @@ static struct ust_app_session *create_ust_app_session(
 		DBG2("UST app session created successfully with handle %d", ret);
 	}
 
-end:
+	*ua_sess_ptr = ua_sess;
+	if (is_created) {
+		*is_created = created;
+	}
+	/* Everything went well. */
+	ret = 0;
+
+error:
 	health_code_update(&health_thread_cmd);
-	return ua_sess;
+	return ret;
 }
 
 /*
@@ -1352,7 +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;
 		}
@@ -2030,10 +2114,10 @@ int ust_app_disable_all_event_glb(struct ltt_ust_session *usess,
 int ust_app_create_channel_glb(struct ltt_ust_session *usess,
 		struct ltt_ust_channel *uchan)
 {
-	int ret = 0;
+	int ret = 0, created;
 	struct lttng_ht_iter iter;
 	struct ust_app *app;
-	struct ust_app_session *ua_sess;
+	struct ust_app_session *ua_sess = NULL;
 
 	/* Very wrong code flow */
 	assert(usess);
@@ -2058,25 +2142,34 @@ int ust_app_create_channel_glb(struct ltt_ust_session *usess,
 		 * that if session exist, it will simply return a pointer to the ust
 		 * app session.
 		 */
-		ua_sess = create_ust_app_session(usess, app);
-		if (ua_sess == NULL) {
-			/* The malloc() failed. */
-			ret = -ENOMEM;
-			goto error_rcu_unlock;
-		} else if (ua_sess == (void *) -1UL) {
-			/*
-			 * The application's socket is not valid. Either a bad socket or a
-			 * timeout on it. We can't inform yet the caller that for a
-			 * specific app, the session failed so we continue here.
-			 */
-			continue;
+		ret = create_ust_app_session(usess, app, &ua_sess, &created);
+		if (ret < 0) {
+			switch (ret) {
+			case -ENOTCONN:
+				/*
+				 * The application's socket is not valid. Either a bad socket
+				 * or a timeout on it. We can't inform the caller that for a
+				 * specific app, the session failed so lets continue here.
+				 */
+				continue;
+			case -ENOMEM:
+			default:
+				goto error_rcu_unlock;
+			}
 		}
+		assert(ua_sess);
 
 		/* Create channel onto application. We don't need the chan ref. */
 		ret = create_ust_app_channel(ua_sess, uchan, app, NULL);
-		if (ret < 0 && ret == -ENOMEM) {
-			/* No more memory is a fatal error. Stop right now. */
-			goto error_rcu_unlock;
+		if (ret < 0) {
+			if (ret == -ENOMEM) {
+				/* No more memory is a fatal error. Stop right now. */
+				goto error_rcu_unlock;
+			}
+			/* Cleanup the created session if it's the case. */
+			if (created) {
+				delete_ust_app_session(app->sock, ua_sess);
+			}
 		}
 	}
 
@@ -2275,42 +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);
 		}
@@ -2350,7 +2428,7 @@ skip_setup:
 	/* This start the UST tracing */
 	ret = ustctl_start_session(app->sock, ua_sess->handle);
 	if (ret < 0) {
-		ERR("Error starting tracing for app pid: %d", app->pid);
+		ERR("Error starting tracing for app pid: %d (ret: %d)", app->pid, ret);
 		goto error_rcu_unlock;
 	}
 
@@ -2402,7 +2480,7 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app)
 	 * from either the application manager thread or the command thread. Simply
 	 * indicate that this is a stop error.
 	 */
-	if (ua_sess->started == 1) {
+	if (!ua_sess->started) {
 		goto error_rcu_unlock;
 	}
 
@@ -2411,7 +2489,7 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app)
 	/* This inhibits UST tracing */
 	ret = ustctl_stop_session(app->sock, ua_sess->handle);
 	if (ret < 0) {
-		ERR("Error stopping tracing for app pid: %d", app->pid);
+		ERR("Error stopping tracing for app pid: %d (ret: %d)", app->pid, ret);
 		goto error_rcu_unlock;
 	}
 
@@ -2592,7 +2670,7 @@ void ust_app_global_update(struct ltt_ust_session *usess, int sock)
 	int ret = 0;
 	struct lttng_ht_iter iter, uiter, iter_ctx;
 	struct ust_app *app;
-	struct ust_app_session *ua_sess;
+	struct ust_app_session *ua_sess = NULL;
 	struct ust_app_channel *ua_chan;
 	struct ust_app_event *ua_event;
 	struct ust_app_ctx *ua_ctx;
@@ -2614,11 +2692,12 @@ void ust_app_global_update(struct ltt_ust_session *usess, int sock)
 		goto error;
 	}
 
-	ua_sess = create_ust_app_session(usess, app);
-	if (ua_sess == NULL || ua_sess == (void *) -1UL) {
-		/* Tracer is gone for this session and has been freed */
+	ret = create_ust_app_session(usess, app, &ua_sess, NULL);
+	if (ret < 0) {
+		/* Tracer is probably gone or ENOMEM. */
 		goto error;
 	}
+	assert(ua_sess);
 
 	/*
 	 * We can iterate safely here over all UST app session sicne the create ust
@@ -2651,12 +2730,6 @@ void ust_app_global_update(struct ltt_ust_session *usess, int sock)
 				/* FIXME: Should we quit here or continue... */
 				continue;
 			}
-
-			ret = set_ust_event_filter(ua_event, app);
-			if (ret < 0) {
-				/* FIXME: Should we quit here or continue... */
-				continue;
-			}
 		}
 	}