+ /*
+ * Create the toplevel ust/ directory in case no apps are running.
+ */
+ chunk_status = lttng_trace_chunk_create_subdirectory(
+ usess->current_trace_chunk,
+ DEFAULT_UST_TRACE_DIR);
+ if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+ ret = LTTNG_ERR_CREATE_DIR_FAIL;
+ goto error;
+ }
+
+ cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app,
+ pid_n.node) {
+ struct ust_app_session *ua_sess;
+ struct ust_registry_session *registry;
+
+ ua_sess = lookup_session_by_app(usess, app);
+ if (!ua_sess) {
+ /* Session not associated with this app. */
+ continue;
+ }
+
+ registry = get_session_registry(ua_sess);
+ if (!registry) {
+ DBG("Application session is being torn down. Skip application.");
+ continue;
+ }
+
+ fmt_ret = asprintf(&pathname_index,
+ DEFAULT_UST_TRACE_DIR "/%s/" DEFAULT_INDEX_DIR,
+ ua_sess->path);
+ if (fmt_ret < 0) {
+ ERR("Failed to format channel index directory");
+ ret = LTTNG_ERR_CREATE_DIR_FAIL;
+ goto error;
+ }
+ /*
+ * Create the index subdirectory which will take care
+ * of implicitly creating the channel's path.
+ */
+ chunk_status = lttng_trace_chunk_create_subdirectory(
+ usess->current_trace_chunk,
+ pathname_index);
+ free(pathname_index);
+ if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+ ret = LTTNG_ERR_CREATE_DIR_FAIL;
+ goto error;
+ }
+ }
+ break;
+ }
+ default:
+ abort();
+ }
+
+ ret = LTTNG_OK;
+error:
+ rcu_read_unlock();
+ return ret;
+}
+
+/*
+ * Clear all the channels of a session.
+ *
+ * Return LTTNG_OK on success or else an LTTng error code.
+ */
+enum lttng_error_code ust_app_clear_session(struct ltt_session *session)
+{
+ int ret;
+ enum lttng_error_code cmd_ret = LTTNG_OK;
+ struct lttng_ht_iter iter;
+ struct ust_app *app;
+ struct ltt_ust_session *usess = session->ust_session;
+
+ assert(usess);
+
+ rcu_read_lock();
+
+ if (usess->active) {
+ ERR("Expecting inactive session %s (%" PRIu64 ")", session->name, session->id);
+ cmd_ret = LTTNG_ERR_FATAL;
+ goto end;
+ }
+
+ switch (usess->buffer_type) {
+ case LTTNG_BUFFER_PER_UID:
+ {
+ struct buffer_reg_uid *reg;
+
+ cds_list_for_each_entry(reg, &usess->buffer_reg_uid_list, lnode) {
+ struct buffer_reg_channel *reg_chan;
+ struct consumer_socket *socket;
+
+ /* Get consumer socket to use to push the metadata.*/
+ socket = consumer_find_socket_by_bitness(reg->bits_per_long,
+ usess->consumer);
+ if (!socket) {
+ cmd_ret = LTTNG_ERR_INVALID;
+ goto error_socket;
+ }
+
+ /* Clear the data channels. */
+ cds_lfht_for_each_entry(reg->registry->channels->ht, &iter.iter,
+ reg_chan, node.node) {
+ ret = consumer_clear_channel(socket,
+ reg_chan->consumer_key);