X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=lttng-sessiond%2Fust-app.c;h=3547679f8bc8dbe1381aae36f46a54a7f3933932;hb=8be98f9a4419d360bce0678981ba3f4b891b0a19;hp=2bee4d90ab7626b7b51c314b67ef539d65441634;hpb=477d7741a6555ba9d2ef0bbfc72fc7877cbbb869;p=lttng-tools.git

diff --git a/lttng-sessiond/ust-app.c b/lttng-sessiond/ust-app.c
index 2bee4d90a..3547679f8 100644
--- a/lttng-sessiond/ust-app.c
+++ b/lttng-sessiond/ust-app.c
@@ -143,6 +143,7 @@ static void delete_ust_app(struct ust_app *app)
 	struct cds_lfht_node *node;
 	struct cds_lfht_iter iter;
 	struct ust_app_session *ua_sess;
+	int sock;
 
 	rcu_read_lock();
 
@@ -167,9 +168,8 @@ static void delete_ust_app(struct ust_app *app)
 	/* Socket is already closed at this point */
 
 	/* Delete ust app sessions info */
-	if (app->sock_closed) {
-		app->key.sock = -1;
-	}
+	sock = app->key.sock;
+	app->key.sock = -1;
 
 	cds_lfht_for_each_entry(app->sessions, &iter, ua_sess, node) {
 		hashtable_del(app->sessions, &iter);
@@ -182,9 +182,13 @@ static void delete_ust_app(struct ust_app *app)
 		goto end;
 	}
 
-	if (!app->sock_closed) {
-		close(app->key.sock);
-	}
+	/*
+	 * Wait until we have removed the key from the sock hash table
+	 * before closing this socket, otherwise an application could
+	 * re-use the socket ID and race with the teardown, using the
+	 * same hash table entry.
+	 */
+	close(sock);
 
 	DBG2("UST app pid %d deleted", app->key.pid);
 	free(app);
@@ -881,10 +885,6 @@ void ust_app_unregister(int sock)
 		goto error;
 	}
 
-	/* We got called because the socket was closed on the remote end. */
-	close(sock);
-	/* Using a flag because we still need "sock" as a key. */
-	lta->sock_closed = 1;
 	hashtable_del(ust_app_ht, &iter);
 	call_rcu(&node->head, delete_ust_app_rcu);
 error:
@@ -983,8 +983,6 @@ void ust_app_clean_list(void)
 
 	cds_lfht_for_each(ust_app_ht, &iter, node) {
 		app = caa_container_of(node, struct ust_app, node);
-		close(app->key.sock);
-		app->sock_closed = 1;
 
 		ret = hashtable_del(ust_app_ht, &iter);
 		if (!ret) {
@@ -1124,6 +1122,10 @@ int ust_app_start_trace(struct ltt_ust_session *usess, struct ust_app *app)
 		goto error_rcu_unlock;
 	}
 
+	/* upon restart, we skip the setup, already done */
+	if (ua_sess->started)
+		goto skip_setup;
+
 	ret = create_ust_app_metadata(ua_sess, usess->pathname, app);
 	if (ret < 0) {
 		goto error_rcu_unlock;
@@ -1167,7 +1169,9 @@ int ust_app_start_trace(struct ltt_ust_session *usess, struct ust_app *app)
 	if (ret < 0) {
 		goto error_rcu_unlock;
 	}
+	ua_sess->started = 1;
 
+skip_setup:
 	/* This start the UST tracing */
 	ret = ustctl_start_session(app->key.sock, ua_sess->handle);
 	if (ret < 0) {
@@ -1187,6 +1191,59 @@ error_rcu_unlock:
 	return -1;
 }
 
+/*
+ * Stop tracing for a specific UST session and app.
+ */
+int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app)
+{
+	int ret = 0;
+	struct ust_app_session *ua_sess;
+
+	DBG("Stopping tracing for ust app pid %d", app->key.pid);
+
+	rcu_read_lock();
+
+	ua_sess = lookup_session_by_app(usess, app);
+	if (ua_sess == NULL) {
+		/* Only malloc can failed so something is really wrong */
+		goto error_rcu_unlock;
+	}
+
+#if 0	/* only useful when periodical flush will be supported */
+	/* need to keep a handle on shm in session for this. */
+	/* Flush all buffers before stopping */
+	ret = ustctl_flush_buffer(usess->sock, usess->metadata->obj);
+	if (ret < 0) {
+		ERR("UST metadata flush failed");
+	}
+
+	cds_list_for_each_entry(ustchan, &usess->channels.head, list) {
+		ret = ustctl_flush_buffer(usess->sock, ustchan->obj);
+		if (ret < 0) {
+			ERR("UST flush buffer error");
+		}
+	}
+#endif
+
+	/* This inhibits UST tracing */
+	ret = ustctl_stop_session(app->key.sock, ua_sess->handle);
+	if (ret < 0) {
+		ERR("Error stopping tracing for app pid: %d", app->key.pid);
+		goto error_rcu_unlock;
+	}
+
+	rcu_read_unlock();
+
+	/* Quiescent wait after stopping trace */
+	ustctl_wait_quiescent(app->key.sock);
+
+	return 0;
+
+error_rcu_unlock:
+	rcu_read_unlock();
+	return -1;
+}
+
 /*
  * Start tracing for the UST session.
  */
@@ -1213,6 +1270,32 @@ int ust_app_start_trace_all(struct ltt_ust_session *usess)
 	return 0;
 }
 
+/*
+ * Start tracing for the UST session.
+ */
+int ust_app_stop_trace_all(struct ltt_ust_session *usess)
+{
+	int ret = 0;
+	struct cds_lfht_iter iter;
+	struct ust_app *app;
+
+	DBG("Stopping all UST traces");
+
+	rcu_read_lock();
+
+	cds_lfht_for_each_entry(ust_app_ht, &iter, app, node) {
+		ret = ust_app_stop_trace(usess, app);
+		if (ret < 0) {
+			/* Continue to next apps even on error */
+			continue;
+		}
+	}
+
+	rcu_read_unlock();
+
+	return 0;
+}
+
 /*
  * Add channels/events from UST global domain to registered apps at sock.
  */