+ cds_lfht_lookup(state->channel_triggers_ht,
+ hash_channel_key(&channel->key),
+ match_channel_trigger_list,
+ &channel->key,
+ &lookup_iter);
+ node = cds_lfht_iter_get_node(&lookup_iter);
+ assert(node);
+ trigger_list = caa_container_of(node,
+ struct lttng_channel_trigger_list,
+ channel_triggers_ht_node);
+
+ trigger_list_element = zmalloc(sizeof(*trigger_list_element));
+ if (!trigger_list_element) {
+ ret = -1;
+ goto end;
+ }
+ CDS_INIT_LIST_HEAD(&trigger_list_element->node);
+ trigger_list_element->trigger = trigger;
+ cds_list_add(&trigger_list_element->node, &trigger_list->list);
+ DBG("[notification-thread] Newly registered trigger bound to channel \"%s\"",
+ channel->name);
+ }
+end:
+ return ret;
+}
+
+static
+bool is_trigger_action_notify(const struct lttng_trigger *trigger)
+{
+ bool is_notify = false;
+ unsigned int i, count;
+ enum lttng_action_status action_status;
+ const struct lttng_action *action =
+ lttng_trigger_get_const_action(trigger);
+ enum lttng_action_type action_type;
+
+ assert(action);
+ action_type = lttng_action_get_type(action);
+ if (action_type == LTTNG_ACTION_TYPE_NOTIFY) {
+ is_notify = true;
+ goto end;
+ } else if (action_type != LTTNG_ACTION_TYPE_LIST) {
+ goto end;
+ }
+
+ action_status = lttng_action_list_get_count(action, &count);
+ assert(action_status == LTTNG_ACTION_STATUS_OK);
+
+ for (i = 0; i < count; i++) {
+ const struct lttng_action *inner_action =
+ lttng_action_list_get_at_index(
+ action, i);
+
+ action_type = lttng_action_get_type(inner_action);
+ if (action_type == LTTNG_ACTION_TYPE_NOTIFY) {
+ is_notify = true;
+ goto end;
+ }
+ }
+
+end:
+ return is_notify;
+}
+
+static bool trigger_name_taken(struct notification_thread_state *state,
+ const struct lttng_trigger *trigger)
+{
+ struct cds_lfht_iter iter;
+
+ /*
+ * No duplicata is allowed in the triggers_by_name_uid_ht.
+ * The match is done against the trigger name and uid.
+ */
+ cds_lfht_lookup(state->triggers_by_name_uid_ht,
+ hash_trigger_by_name_uid(trigger),
+ match_trigger_by_name_uid,
+ trigger,
+ &iter);
+ return !!cds_lfht_iter_get_node(&iter);
+}
+
+static
+enum lttng_error_code generate_trigger_name(
+ struct notification_thread_state *state,
+ struct lttng_trigger *trigger, const char **name)
+{
+ enum lttng_error_code ret_code = LTTNG_OK;
+ bool taken = false;
+ enum lttng_trigger_status status;
+
+ do {
+ const int ret = lttng_trigger_generate_name(trigger,
+ state->trigger_id.name_offset++);
+ if (ret) {
+ /* The only reason this can fail right now. */
+ ret_code = LTTNG_ERR_NOMEM;
+ break;
+ }
+
+ status = lttng_trigger_get_name(trigger, name);
+ assert(status == LTTNG_TRIGGER_STATUS_OK);
+
+ taken = trigger_name_taken(state, trigger);
+ } while (taken || state->trigger_id.name_offset == UINT64_MAX);
+
+ return ret_code;
+}
+
+static inline
+void notif_thread_state_remove_trigger_ht_elem(
+ struct notification_thread_state *state,
+ struct lttng_trigger_ht_element *trigger_ht_element)
+{
+ assert(state);
+ assert(trigger_ht_element);
+
+ cds_lfht_del(state->triggers_ht, &trigger_ht_element->node);
+ cds_lfht_del(state->triggers_by_name_uid_ht, &trigger_ht_element->node_by_name_uid);
+}
+
+static
+enum lttng_error_code setup_tracer_notifier(
+ struct notification_thread_state *state,
+ struct lttng_trigger *trigger)
+{
+ enum lttng_error_code ret;
+ enum event_notifier_error_accounting_status error_accounting_status;
+ struct cds_lfht_node *node;
+ uint64_t error_counter_index = 0;
+ struct lttng_condition *condition = lttng_trigger_get_condition(trigger);
+ struct notification_trigger_tokens_ht_element *trigger_tokens_ht_element = NULL;
+
+ trigger_tokens_ht_element = zmalloc(sizeof(*trigger_tokens_ht_element));
+ if (!trigger_tokens_ht_element) {
+ ret = LTTNG_ERR_NOMEM;
+ goto end;
+ }
+
+ /* Add trigger token to the trigger_tokens_ht. */
+ cds_lfht_node_init(&trigger_tokens_ht_element->node);
+ trigger_tokens_ht_element->token = LTTNG_OPTIONAL_GET(trigger->tracer_token);
+ trigger_tokens_ht_element->trigger = trigger;
+
+ node = cds_lfht_add_unique(state->trigger_tokens_ht,
+ hash_key_u64(&trigger_tokens_ht_element->token, lttng_ht_seed),
+ match_trigger_token,
+ &trigger_tokens_ht_element->token,
+ &trigger_tokens_ht_element->node);
+ if (node != &trigger_tokens_ht_element->node) {
+ ret = LTTNG_ERR_TRIGGER_EXISTS;
+ goto error_free_ht_element;
+ }
+
+ error_accounting_status = event_notifier_error_accounting_register_event_notifier(
+ trigger, &error_counter_index);
+ if (error_accounting_status != EVENT_NOTIFIER_ERROR_ACCOUNTING_STATUS_OK) {
+ if (error_accounting_status == EVENT_NOTIFIER_ERROR_ACCOUNTING_STATUS_NO_INDEX_AVAILABLE) {
+ DBG("Trigger list error accounting counter full.");
+ ret = LTTNG_ERR_EVENT_NOTIFIER_ERROR_ACCOUNTING_FULL;
+ } else {
+ ERR("Error registering trigger for error accounting");
+ ret = LTTNG_ERR_EVENT_NOTIFIER_REGISTRATION;
+ }
+
+ goto error_remove_ht_element;
+ }
+
+ lttng_condition_event_rule_matches_set_error_counter_index(
+ condition, error_counter_index);
+
+ ret = LTTNG_OK;
+ goto end;
+
+error_remove_ht_element:
+ cds_lfht_del(state->trigger_tokens_ht, &trigger_tokens_ht_element->node);
+error_free_ht_element:
+ free(trigger_tokens_ht_element);
+end:
+ return ret;
+}
+
+/*
+ * FIXME A client's credentials are not checked when registering a trigger.
+ *
+ * The effects of this are benign since:
+ * - The client will succeed in registering the trigger, as it is valid,
+ * - The trigger will, internally, be bound to the channel/session,
+ * - The notifications will not be sent since the client's credentials
+ * are checked against the channel at that moment.
+ *
+ * If this function returns a non-zero value, it means something is
+ * fundamentally broken and the whole subsystem/thread will be torn down.
+ *
+ * If a non-fatal error occurs, just set the cmd_result to the appropriate
+ * error code.
+ */
+static
+int handle_notification_thread_command_register_trigger(
+ struct notification_thread_state *state,
+ struct lttng_trigger *trigger,
+ bool is_trigger_anonymous,
+ enum lttng_error_code *cmd_result)
+{
+ int ret = 0;
+ struct lttng_condition *condition;
+ struct notification_client_list *client_list = NULL;
+ struct lttng_trigger_ht_element *trigger_ht_element = NULL;
+ struct cds_lfht_node *node;
+ const char* trigger_name;
+ bool free_trigger = true;
+ struct lttng_evaluation *evaluation = NULL;
+ struct lttng_credentials object_creds;
+ uid_t object_uid;
+ gid_t object_gid;
+ enum action_executor_status executor_status;
+ const uint64_t trigger_tracer_token =
+ state->trigger_id.next_tracer_token++;
+
+ rcu_read_lock();
+
+ /* Set the trigger's tracer token. */
+ lttng_trigger_set_tracer_token(trigger, trigger_tracer_token);
+
+ if (!is_trigger_anonymous) {
+ if (lttng_trigger_get_name(trigger, &trigger_name) ==
+ LTTNG_TRIGGER_STATUS_UNSET) {
+ const enum lttng_error_code ret_code =
+ generate_trigger_name(state, trigger,
+ &trigger_name);
+
+ if (ret_code != LTTNG_OK) {
+ /* Fatal error. */
+ ret = -1;
+ *cmd_result = ret_code;
+ goto error;
+ }
+ } else if (trigger_name_taken(state, trigger)) {
+ /* Not a fatal error. */
+ *cmd_result = LTTNG_ERR_TRIGGER_EXISTS;
+ ret = 0;
+ goto error;
+ }
+ } else {
+ trigger_name = "(anonymous)";
+ }
+
+ condition = lttng_trigger_get_condition(trigger);
+ assert(condition);
+
+ /* Some conditions require tracers to implement a minimal ABI version. */
+ if (!condition_is_supported(condition)) {
+ *cmd_result = LTTNG_ERR_NOT_SUPPORTED;
+ goto error;
+ }
+
+ trigger_ht_element = zmalloc(sizeof(*trigger_ht_element));
+ if (!trigger_ht_element) {
+ ret = -1;
+ goto error;
+ }
+
+ /* Add trigger to the trigger_ht. */
+ cds_lfht_node_init(&trigger_ht_element->node);
+ cds_lfht_node_init(&trigger_ht_element->node_by_name_uid);
+ trigger_ht_element->trigger = trigger;
+
+ node = cds_lfht_add_unique(state->triggers_ht,
+ lttng_condition_hash(condition),
+ match_trigger,
+ trigger,
+ &trigger_ht_element->node);
+ if (node != &trigger_ht_element->node) {
+ /* Not a fatal error, simply report it to the client. */
+ *cmd_result = LTTNG_ERR_TRIGGER_EXISTS;
+ goto error_free_ht_element;
+ }
+
+ node = cds_lfht_add_unique(state->triggers_by_name_uid_ht,
+ hash_trigger_by_name_uid(trigger),
+ match_trigger_by_name_uid,
+ trigger,
+ &trigger_ht_element->node_by_name_uid);
+ if (node != &trigger_ht_element->node_by_name_uid) {
+ /* Internal error: add to triggers_ht should have failed. */
+ ret = -1;
+ goto error_free_ht_element;
+ }
+
+ /* From this point consider the trigger registered. */
+ lttng_trigger_set_as_registered(trigger);
+
+ /*
+ * Some triggers might need a tracer notifier depending on its
+ * condition and actions.
+ */
+ if (lttng_trigger_needs_tracer_notifier(trigger)) {
+ enum lttng_error_code error_code;
+
+ error_code = setup_tracer_notifier(state, trigger);
+ if (error_code != LTTNG_OK) {
+ notif_thread_state_remove_trigger_ht_elem(state,
+ trigger_ht_element);
+ if (error_code == LTTNG_ERR_NOMEM) {
+ ret = -1;
+ } else {
+ *cmd_result = error_code;
+ ret = 0;
+ }
+
+ goto error_free_ht_element;
+ }
+ }
+
+ /*
+ * The rest only applies to triggers that have a "notify" action.
+ * It is not skipped as this is the only action type currently
+ * supported.
+ */
+ if (is_trigger_action_notify(trigger)) {
+ /*
+ * Find or create the client list of this condition. It may
+ * already be present if another trigger is already registered
+ * with the same condition.
+ */
+ client_list = get_client_list_from_condition(state, condition);
+ if (!client_list) {
+ /*
+ * No client list for this condition yet. We create new
+ * one and build it up.
+ */
+ client_list = notification_client_list_create(state, condition);
+ if (!client_list) {
+ ERR("Error creating notification client list for trigger %s", trigger->name);
+ goto error_free_ht_element;
+ }
+ }
+
+ CDS_INIT_LIST_HEAD(&trigger_ht_element->client_list_trigger_node);
+
+ pthread_mutex_lock(&client_list->lock);
+ cds_list_add(&trigger_ht_element->client_list_trigger_node, &client_list->triggers_list);
+ pthread_mutex_unlock(&client_list->lock);