+ pthread_mutex_unlock(®istry->lock);
+ }
+
+end:
+ rcu_read_unlock();
+ return ret;
+}
+
+/*
+ * Command LTTNG_REGENERATE_METADATA from the lttng-ctl library.
+ *
+ * Ask the consumer to truncate the existing metadata file(s) and
+ * then regenerate the metadata. Live and per-pid sessions are not
+ * supported and return an error.
+ *
+ * Return LTTNG_OK on success or else a LTTNG_ERR code.
+ */
+int cmd_regenerate_metadata(struct ltt_session *session)
+{
+ int ret;
+
+ assert(session);
+
+ ret = check_regenerate_metadata_support(session);
+ if (ret) {
+ goto end;
+ }
+
+ if (session->kernel_session) {
+ ret = kernctl_session_regenerate_metadata(
+ session->kernel_session->fd);
+ if (ret < 0) {
+ ERR("Failed to regenerate the kernel metadata");
+ goto end;
+ }
+ }
+
+ if (session->ust_session) {
+ ret = ust_regenerate_metadata(session->ust_session);
+ if (ret < 0) {
+ ERR("Failed to regenerate the UST metadata");
+ goto end;
+ }
+ }
+ DBG("Cmd metadata regenerate for session %s", session->name);
+ ret = LTTNG_OK;
+
+end:
+ return ret;
+}
+
+/*
+ * Command LTTNG_REGENERATE_STATEDUMP from the lttng-ctl library.
+ *
+ * Ask the tracer to regenerate a new statedump.
+ *
+ * Return LTTNG_OK on success or else a LTTNG_ERR code.
+ */
+int cmd_regenerate_statedump(struct ltt_session *session)
+{
+ int ret;
+
+ assert(session);
+
+ if (!session->active) {
+ ret = LTTNG_ERR_SESSION_NOT_STARTED;
+ goto end;
+ }
+
+ if (session->kernel_session) {
+ ret = kernctl_session_regenerate_statedump(
+ session->kernel_session->fd);
+ /*
+ * Currently, the statedump in kernel can only fail if out
+ * of memory.
+ */
+ if (ret < 0) {
+ if (ret == -ENOMEM) {
+ ret = LTTNG_ERR_REGEN_STATEDUMP_NOMEM;
+ } else {
+ ret = LTTNG_ERR_REGEN_STATEDUMP_FAIL;
+ }
+ ERR("Failed to regenerate the kernel statedump");
+ goto end;
+ }
+ }
+
+ if (session->ust_session) {
+ ret = ust_app_regenerate_statedump_all(session->ust_session);
+ /*
+ * Currently, the statedump in UST always returns 0.
+ */
+ if (ret < 0) {
+ ret = LTTNG_ERR_REGEN_STATEDUMP_FAIL;
+ ERR("Failed to regenerate the UST statedump");
+ goto end;
+ }
+ }
+ DBG("Cmd regenerate statedump for session %s", session->name);
+ ret = LTTNG_OK;
+
+end:
+ return ret;
+}
+
+static
+enum lttng_error_code synchronize_tracer_notifier_register(
+ struct notification_thread_handle *notification_thread,
+ struct lttng_trigger *trigger, const struct lttng_credentials *cmd_creds)
+{
+ enum lttng_error_code ret_code;
+ const struct lttng_condition *condition =
+ lttng_trigger_get_const_condition(trigger);
+ const char *trigger_name;
+ uid_t trigger_owner;
+ enum lttng_trigger_status trigger_status;
+ const enum lttng_domain_type trigger_domain =
+ lttng_trigger_get_underlying_domain_type_restriction(
+ trigger);
+
+ trigger_status = lttng_trigger_get_owner_uid(trigger, &trigger_owner);
+ assert(trigger_status == LTTNG_TRIGGER_STATUS_OK);
+
+ assert(condition);
+ assert(lttng_condition_get_type(condition) ==
+ LTTNG_CONDITION_TYPE_EVENT_RULE_MATCHES);
+
+ trigger_status = lttng_trigger_get_name(trigger, &trigger_name);
+ trigger_name = trigger_status == LTTNG_TRIGGER_STATUS_OK ?
+ trigger_name : "(anonymous)";
+
+ session_lock_list();
+ switch (trigger_domain) {
+ case LTTNG_DOMAIN_KERNEL:
+ {
+ ret_code = kernel_register_event_notifier(trigger, cmd_creds);
+ if (ret_code != LTTNG_OK) {
+ enum lttng_error_code notif_thread_unregister_ret;
+
+ notif_thread_unregister_ret =
+ notification_thread_command_unregister_trigger(
+ notification_thread, trigger);
+
+ if (notif_thread_unregister_ret != LTTNG_OK) {
+ /* Return the original error code. */
+ ERR("Failed to unregister trigger from notification thread during error recovery: trigger name = '%s', trigger owner uid = %d, error code = %d",
+ trigger_name,
+ (int) trigger_owner,
+ ret_code);
+ }
+ }
+ break;
+ }
+ case LTTNG_DOMAIN_UST:
+ ust_app_global_update_all_event_notifier_rules();
+ break;
+ case LTTNG_DOMAIN_JUL:
+ case LTTNG_DOMAIN_LOG4J:
+ case LTTNG_DOMAIN_PYTHON:
+ {
+ /* Agent domains. */
+ struct agent *agt = agent_find_by_event_notifier_domain(
+ trigger_domain);
+
+ if (!agt) {
+ agt = agent_create(trigger_domain);
+ if (!agt) {
+ ret_code = LTTNG_ERR_NOMEM;
+ goto end_unlock_session_list;
+ }
+
+ agent_add(agt, the_trigger_agents_ht_by_domain);
+ }
+
+ ret_code = trigger_agent_enable(trigger, agt);
+ if (ret_code != LTTNG_OK) {
+ goto end_unlock_session_list;
+ }
+
+ break;
+ }
+ case LTTNG_DOMAIN_NONE:
+ default:
+ abort();
+ }
+
+ ret_code = LTTNG_OK;
+end_unlock_session_list:
+ session_unlock_list();
+ return ret_code;
+}
+
+enum lttng_error_code cmd_register_trigger(const struct lttng_credentials *cmd_creds,
+ struct lttng_trigger *trigger,
+ bool is_trigger_anonymous,
+ struct notification_thread_handle *notification_thread,
+ struct lttng_trigger **return_trigger)
+{
+ enum lttng_error_code ret_code;
+ const char *trigger_name;
+ uid_t trigger_owner;
+ enum lttng_trigger_status trigger_status;
+
+ trigger_status = lttng_trigger_get_name(trigger, &trigger_name);
+ trigger_name = trigger_status == LTTNG_TRIGGER_STATUS_OK ?
+ trigger_name : "(anonymous)";
+
+ trigger_status = lttng_trigger_get_owner_uid(
+ trigger, &trigger_owner);
+ assert(trigger_status == LTTNG_TRIGGER_STATUS_OK);
+
+ DBG("Running register trigger command: trigger name = '%s', trigger owner uid = %d, command creds uid = %d",
+ trigger_name, (int) trigger_owner,
+ (int) lttng_credentials_get_uid(cmd_creds));
+
+ /*
+ * Validate the trigger credentials against the command credentials.
+ * Only the root user can register a trigger with non-matching
+ * credentials.
+ */
+ if (!lttng_credentials_is_equal_uid(
+ lttng_trigger_get_credentials(trigger),
+ cmd_creds)) {
+ if (lttng_credentials_get_uid(cmd_creds) != 0) {
+ ERR("Trigger credentials do not match the command credentials: trigger name = '%s', trigger owner uid = %d, command creds uid = %d",
+ trigger_name, (int) trigger_owner,
+ (int) lttng_credentials_get_uid(cmd_creds));
+ ret_code = LTTNG_ERR_INVALID_TRIGGER;
+ goto end;
+ }
+ }
+
+ /*
+ * The bytecode generation also serves as a validation step for the
+ * bytecode expressions.
+ */
+ ret_code = lttng_trigger_generate_bytecode(trigger, cmd_creds);
+ if (ret_code != LTTNG_OK) {
+ ERR("Failed to generate bytecode of trigger: trigger name = '%s', trigger owner uid = %d, error code = %d",
+ trigger_name, (int) trigger_owner, ret_code);
+ goto end;
+ }
+
+ /*
+ * A reference to the trigger is acquired by the notification thread.
+ * It is safe to return the same trigger to the caller since it the
+ * other user holds a reference.
+ *
+ * The trigger is modified during the execution of the
+ * "register trigger" command. However, by the time the command returns,
+ * it is safe to use without any locking as its properties are
+ * immutable.
+ */
+ ret_code = notification_thread_command_register_trigger(
+ notification_thread, trigger, is_trigger_anonymous);
+ if (ret_code != LTTNG_OK) {
+ DBG("Failed to register trigger to notification thread: trigger name = '%s', trigger owner uid = %d, error code = %d",
+ trigger_name, (int) trigger_owner, ret_code);
+ goto end;
+ }
+
+ trigger_status = lttng_trigger_get_name(trigger, &trigger_name);
+ trigger_name = trigger_status == LTTNG_TRIGGER_STATUS_OK ?
+ trigger_name : "(anonymous)";
+
+ /*
+ * Synchronize tracers if the trigger adds an event notifier.
+ */
+ if (lttng_trigger_needs_tracer_notifier(trigger)) {
+ ret_code = synchronize_tracer_notifier_register(notification_thread,
+ trigger, cmd_creds);
+ if (ret_code != LTTNG_OK) {
+ ERR("Error registering tracer notifier: %s",
+ lttng_strerror(-ret_code));
+ goto end;
+ }
+ }
+
+ /*
+ * Return an updated trigger to the client.
+ *
+ * Since a modified version of the same trigger is returned, acquire a
+ * reference to the trigger so the caller doesn't have to care if those
+ * are distinct instances or not.
+ */
+ if (ret_code == LTTNG_OK) {
+ lttng_trigger_get(trigger);
+ *return_trigger = trigger;
+ /* Ownership of trigger was transferred to caller. */
+ trigger = NULL;
+ }
+end:
+ return ret_code;
+}
+
+static
+enum lttng_error_code synchronize_tracer_notifier_unregister(
+ const struct lttng_trigger *trigger)
+{
+ enum lttng_error_code ret_code;
+ const struct lttng_condition *condition =
+ lttng_trigger_get_const_condition(trigger);
+ const enum lttng_domain_type trigger_domain =
+ lttng_trigger_get_underlying_domain_type_restriction(
+ trigger);
+
+ assert(condition);
+ assert(lttng_condition_get_type(condition) ==
+ LTTNG_CONDITION_TYPE_EVENT_RULE_MATCHES);
+
+ session_lock_list();
+ switch (trigger_domain) {
+ case LTTNG_DOMAIN_KERNEL:
+ ret_code = kernel_unregister_event_notifier(trigger);
+ if (ret_code != LTTNG_OK) {
+ goto end_unlock_session_list;
+ }
+
+ break;
+ case LTTNG_DOMAIN_UST:
+ ust_app_global_update_all_event_notifier_rules();
+ break;
+ case LTTNG_DOMAIN_JUL:
+ case LTTNG_DOMAIN_LOG4J:
+ case LTTNG_DOMAIN_PYTHON:
+ {
+ /* Agent domains. */
+ struct agent *agt = agent_find_by_event_notifier_domain(
+ trigger_domain);
+
+ /*
+ * This trigger was never registered in the first place. Calling
+ * this function under those circumstances is an internal error.
+ */
+ assert(agt);
+ ret_code = trigger_agent_disable(trigger, agt);
+ if (ret_code != LTTNG_OK) {
+ goto end_unlock_session_list;
+ }
+
+ break;
+ }
+ case LTTNG_DOMAIN_NONE:
+ default:
+ abort();