+static
+int _session_set_trace_chunk_no_lock_check(struct ltt_session *session,
+ struct lttng_trace_chunk *new_trace_chunk,
+ struct lttng_trace_chunk **_current_trace_chunk)
+{
+ int ret;
+ unsigned int i, refs_to_acquire = 0, refs_acquired = 0, refs_to_release = 0;
+ struct cds_lfht_iter iter;
+ struct consumer_socket *socket;
+ struct lttng_trace_chunk *current_trace_chunk;
+ uint64_t chunk_id;
+ enum lttng_trace_chunk_status chunk_status;
+
+ rcu_read_lock();
+ /*
+ * Ownership of current trace chunk is transferred to
+ * `current_trace_chunk`.
+ */
+ current_trace_chunk = session->current_trace_chunk;
+ session->current_trace_chunk = NULL;
+ if (session->ust_session) {
+ lttng_trace_chunk_put(
+ session->ust_session->current_trace_chunk);
+ session->ust_session->current_trace_chunk = NULL;
+ }
+ if (session->kernel_session) {
+ lttng_trace_chunk_put(
+ session->kernel_session->current_trace_chunk);
+ session->kernel_session->current_trace_chunk = NULL;
+ }
+ if (!new_trace_chunk) {
+ ret = 0;
+ goto end;
+ }
+ chunk_status = lttng_trace_chunk_get_id(new_trace_chunk, &chunk_id);
+ assert(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);
+
+ refs_to_acquire = 1;
+ refs_to_acquire += !!session->ust_session;
+ refs_to_acquire += !!session->kernel_session;
+
+ for (refs_acquired = 0; refs_acquired < refs_to_acquire;
+ refs_acquired++) {
+ if (!lttng_trace_chunk_get(new_trace_chunk)) {
+ ERR("Failed to acquire reference to new trace chunk of session \"%s\"",
+ session->name);
+ goto error;
+ }
+ }
+
+ if (session->ust_session) {
+ const uint64_t relayd_id =
+ session->ust_session->consumer->net_seq_index;
+ const bool is_local_trace =
+ session->ust_session->consumer->type ==
+ CONSUMER_DST_LOCAL;
+
+ session->ust_session->current_trace_chunk = new_trace_chunk;
+ if (is_local_trace) {
+ enum lttng_error_code ret_error_code;
+
+ ret_error_code = ust_app_create_channel_subdirectories(
+ session->ust_session);
+ if (ret_error_code != LTTNG_OK) {
+ ret = -ret_error_code;
+ goto error;
+ }
+ }
+ cds_lfht_for_each_entry(
+ session->ust_session->consumer->socks->ht,
+ &iter, socket, node.node) {
+ pthread_mutex_lock(socket->lock);
+ ret = consumer_create_trace_chunk(socket,
+ relayd_id,
+ session->id, new_trace_chunk);
+ pthread_mutex_unlock(socket->lock);
+ if (ret) {
+ goto error;
+ }
+ }
+ }
+ if (session->kernel_session) {
+ const uint64_t relayd_id =
+ session->kernel_session->consumer->net_seq_index;
+ const bool is_local_trace =
+ session->kernel_session->consumer->type ==
+ CONSUMER_DST_LOCAL;
+
+ session->kernel_session->current_trace_chunk = new_trace_chunk;
+ if (is_local_trace) {
+ enum lttng_error_code ret_error_code;
+
+ ret_error_code = kernel_create_channel_subdirectories(
+ session->kernel_session);
+ if (ret_error_code != LTTNG_OK) {
+ ret = -ret_error_code;
+ goto error;
+ }
+ }
+ cds_lfht_for_each_entry(
+ session->kernel_session->consumer->socks->ht,
+ &iter, socket, node.node) {
+ pthread_mutex_lock(socket->lock);
+ ret = consumer_create_trace_chunk(socket,
+ relayd_id,
+ session->id, new_trace_chunk);
+ pthread_mutex_unlock(socket->lock);
+ if (ret) {
+ goto error;
+ }
+ }
+ }
+
+ /*
+ * Update local current trace chunk state last, only if all remote
+ * creations succeeded.
+ */
+ session->current_trace_chunk = new_trace_chunk;
+ LTTNG_OPTIONAL_SET(&session->most_recent_chunk_id, chunk_id);
+end:
+ if (_current_trace_chunk) {
+ *_current_trace_chunk = current_trace_chunk;
+ current_trace_chunk = NULL;
+ }
+end_no_move:
+ rcu_read_unlock();
+ lttng_trace_chunk_put(current_trace_chunk);
+ return ret;
+error:
+ if (session->ust_session) {
+ session->ust_session->current_trace_chunk = NULL;
+ }
+ if (session->kernel_session) {
+ session->kernel_session->current_trace_chunk = NULL;
+ }
+ /*
+ * Release references taken in the case where all references could not
+ * be acquired.
+ */
+ refs_to_release = refs_to_acquire - refs_acquired;
+ for (i = 0; i < refs_to_release; i++) {
+ lttng_trace_chunk_put(new_trace_chunk);
+ }
+ ret = -1;
+ goto end_no_move;
+}
+
+bool session_output_supports_trace_chunks(const struct ltt_session *session)
+{
+ const struct consumer_output *output = session->kernel_session ?
+ session->kernel_session->consumer :
+ session->ust_session->consumer;
+
+ if (output->type == CONSUMER_DST_LOCAL) {
+ return true;
+ } else {
+ if (output->relay_major_version > 2) {
+ return true;
+ } else if (output->relay_major_version == 2 &&
+ output->relay_minor_version >= 11) {
+ return true;
+ }
+ }
+ return false;
+}
+
+struct lttng_trace_chunk *session_create_new_trace_chunk(
+ const struct ltt_session *session,
+ const struct consumer_output *consumer_output_override,
+ const char *session_base_path_override,
+ const char *chunk_name_override)
+{
+ int ret;
+ struct lttng_trace_chunk *trace_chunk = NULL;
+ enum lttng_trace_chunk_status chunk_status;
+ const time_t chunk_creation_ts = time(NULL);
+ bool is_local_trace;
+ const char *base_path;
+ struct lttng_directory_handle session_output_directory;
+ const struct lttng_credentials session_credentials = {
+ .uid = session->uid,
+ .gid = session->gid,
+ };
+ uint64_t next_chunk_id;
+ const struct consumer_output *output;
+
+ if (consumer_output_override) {
+ output = consumer_output_override;
+ } else {
+ assert(session->ust_session || session->kernel_session);
+ output = session->ust_session ?
+ session->ust_session->consumer :
+ session->kernel_session->consumer;
+ }
+
+ is_local_trace = output->type == CONSUMER_DST_LOCAL;
+ base_path = session_base_path_override ? :
+ consumer_output_get_base_path(output);
+
+ if (chunk_creation_ts == (time_t) -1) {
+ PERROR("Failed to sample time while creation session \"%s\" trace chunk",
+ session->name);
+ goto error;
+ }
+
+ next_chunk_id = session->most_recent_chunk_id.is_set ?
+ session->most_recent_chunk_id.value + 1 : 0;
+
+ trace_chunk = lttng_trace_chunk_create(next_chunk_id,
+ chunk_creation_ts);
+ if (!trace_chunk) {
+ goto error;
+ }
+
+ if (chunk_name_override) {
+ chunk_status = lttng_trace_chunk_override_name(trace_chunk,
+ chunk_name_override);
+ if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+ goto error;
+ }
+ }
+
+ if (!is_local_trace) {
+ /*
+ * No need to set crendentials and output directory
+ * for remote trace chunks.
+ */
+ goto end;
+ }
+
+ chunk_status = lttng_trace_chunk_set_credentials(trace_chunk,
+ &session_credentials);
+ if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+ goto error;
+ }
+
+ DBG("Creating base output directory of session \"%s\" at %s",
+ session->name, base_path);
+ ret = utils_mkdir_recursive(base_path, S_IRWXU | S_IRWXG,
+ session->uid, session->gid);
+ if (ret) {
+ goto error;
+ }
+ ret = lttng_directory_handle_init(&session_output_directory,
+ base_path);
+ if (ret) {
+ goto error;
+ }
+ chunk_status = lttng_trace_chunk_set_as_owner(trace_chunk,
+ &session_output_directory);
+ lttng_directory_handle_fini(&session_output_directory);
+ if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+ goto error;
+ }
+end:
+ return trace_chunk;
+error:
+ lttng_trace_chunk_put(trace_chunk);
+ trace_chunk = NULL;
+ goto end;
+}
+
+int session_close_trace_chunk(const struct ltt_session *session,
+ struct lttng_trace_chunk *trace_chunk,
+ const enum lttng_trace_chunk_command_type *close_command)
+{
+ int ret = 0;
+ bool error_occurred = false;
+ struct cds_lfht_iter iter;
+ struct consumer_socket *socket;
+ enum lttng_trace_chunk_status chunk_status;
+ const time_t chunk_close_timestamp = time(NULL);
+
+ if (close_command) {
+ chunk_status = lttng_trace_chunk_set_close_command(
+ trace_chunk, *close_command);
+ if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+ ret = -1;
+ goto end;
+ }
+ }
+
+ if (chunk_close_timestamp == (time_t) -1) {
+ ERR("Failed to sample the close timestamp of the current trace chunk of session \"%s\"",
+ session->name);
+ ret = -1;
+ goto end;
+ }
+ chunk_status = lttng_trace_chunk_set_close_timestamp(trace_chunk,
+ chunk_close_timestamp);
+ if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+ ERR("Failed to set the close timestamp of the current trace chunk of session \"%s\"",
+ session->name);
+ ret = -1;
+ goto end;
+ }
+
+ if (session->ust_session) {
+ cds_lfht_for_each_entry(
+ session->ust_session->consumer->socks->ht,
+ &iter, socket, node.node) {
+ pthread_mutex_lock(socket->lock);
+ ret = consumer_close_trace_chunk(socket,
+ session->consumer->net_seq_index,
+ session->id,
+ trace_chunk);
+ pthread_mutex_unlock(socket->lock);
+ if (ret) {
+ ERR("Failed to close trace chunk on user space consumer");
+ error_occurred = true;
+ }
+ }
+ }
+ if (session->kernel_session) {
+ cds_lfht_for_each_entry(
+ session->kernel_session->consumer->socks->ht,
+ &iter, socket, node.node) {
+ pthread_mutex_lock(socket->lock);
+ ret = consumer_close_trace_chunk(socket,
+ session->consumer->net_seq_index,
+ session->id,
+ trace_chunk);
+ pthread_mutex_unlock(socket->lock);
+ if (ret) {
+ ERR("Failed to close trace chunk on kernel consumer");
+ error_occurred = true;
+ }
+ }
+ }
+ ret = error_occurred ? -1 : 0;
+end:
+ return ret;
+}
+
+/*
+ * Set a session's current trace chunk.
+ *
+ * Must be called with the session lock held.
+ */
+int session_set_trace_chunk(struct ltt_session *session,
+ struct lttng_trace_chunk *new_trace_chunk,
+ struct lttng_trace_chunk **current_trace_chunk)
+{
+ ASSERT_LOCKED(session->lock);
+ return _session_set_trace_chunk_no_lock_check(session, new_trace_chunk,
+ current_trace_chunk);
+}
+
+static
+void session_notify_destruction(const struct ltt_session *session)
+{
+ size_t i;
+ const size_t count = lttng_dynamic_array_get_count(
+ &session->destroy_notifiers);
+
+ for (i = 0; i < count; i++) {
+ const struct ltt_session_destroy_notifier_element *element =
+ lttng_dynamic_array_get_element(
+ &session->destroy_notifiers, i);
+
+ element->notifier(session, element->user_data);
+ }
+}
+
+static
+void session_release(struct urcu_ref *ref)
+{
+ int ret;
+ struct ltt_ust_session *usess;
+ struct ltt_kernel_session *ksess;
+ struct ltt_session *session = container_of(ref, typeof(*session), ref);
+
+ assert(!session->chunk_being_archived);
+
+ usess = session->ust_session;
+ ksess = session->kernel_session;
+
+ session_notify_destruction(session);
+ lttng_dynamic_array_reset(&session->destroy_notifiers);
+ if (session->current_trace_chunk) {
+ ret = session_close_trace_chunk(session, session->current_trace_chunk, NULL);
+ if (ret) {
+ ERR("Failed to close the current trace chunk of session \"%s\" during its release",
+ session->name);
+ }
+ ret = _session_set_trace_chunk_no_lock_check(session, NULL, NULL);
+ if (ret) {
+ ERR("Failed to release the current trace chunk of session \"%s\" during its release",
+ session->name);
+ }
+ }
+
+ /* Clean kernel session teardown */
+ kernel_destroy_session(ksess);
+ session->kernel_session = NULL;
+
+ /* UST session teardown */
+ if (usess) {
+ /* Close any relayd session */
+ consumer_output_send_destroy_relayd(usess->consumer);
+
+ /* Destroy every UST application related to this session. */
+ ret = ust_app_destroy_trace_all(usess);
+ if (ret) {
+ ERR("Error in ust_app_destroy_trace_all");
+ }
+
+ /* Clean up the rest. */
+ trace_ust_destroy_session(usess);
+ session->ust_session = NULL;
+ }
+
+ /*
+ * Must notify the kernel thread here to update it's poll set in order to
+ * remove the channel(s)' fd just destroyed.
+ */
+ ret = notify_thread_pipe(kernel_poll_pipe[1]);
+ if (ret < 0) {
+ PERROR("write kernel poll pipe");
+ }
+
+ DBG("Destroying session %s (id %" PRIu64 ")", session->name, session->id);
+
+ consumer_output_put(session->consumer);
+ snapshot_destroy(&session->snapshot);
+
+ pthread_mutex_destroy(&session->lock);
+
+ if (session->published) {
+ ASSERT_LOCKED(ltt_session_list.lock);
+ del_session_list(session);
+ del_session_ht(session);
+ pthread_cond_broadcast(<t_session_list.removal_cond);
+ }
+ free(session->last_archived_chunk_name);
+ free(session);
+}
+
+/*
+ * Acquire a reference to a session.
+ * This function may fail (return false); its return value must be checked.
+ */
+bool session_get(struct ltt_session *session)
+{
+ return urcu_ref_get_unless_zero(&session->ref);
+}
+
+/*
+ * Release a reference to a session.
+ */
+void session_put(struct ltt_session *session)
+{
+ if (!session) {
+ return;
+ }
+ /*
+ * The session list lock must be held as any session_put()
+ * may cause the removal of the session from the session_list.
+ */
+ ASSERT_LOCKED(ltt_session_list.lock);
+ assert(session->ref.refcount);
+ urcu_ref_put(&session->ref, session_release);
+}
+
+/*
+ * Destroy a session.
+ *
+ * This method does not immediately release/free the session as other
+ * components may still hold a reference to the session. However,
+ * the session should no longer be presented to the user.
+ *
+ * Releases the session list's reference to the session
+ * and marks it as destroyed. Iterations on the session list should be
+ * mindful of the "destroyed" flag.
+ */
+void session_destroy(struct ltt_session *session)
+{
+ assert(!session->destroyed);
+ session->destroyed = true;
+ session_put(session);
+}
+
+int session_add_destroy_notifier(struct ltt_session *session,
+ ltt_session_destroy_notifier notifier, void *user_data)
+{
+ const struct ltt_session_destroy_notifier_element element = {
+ .notifier = notifier,
+ .user_data = user_data
+ };
+
+ return lttng_dynamic_array_add_element(&session->destroy_notifiers,
+ &element);
+}
+