+ /*
+ * 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");
+ ret = LTTNG_ERR_INVALID_TRIGGER;
+ goto end;
+ }
+ }
+
+ /*
+ * The bytecode generation also serves as a validation step for the
+ * bytecode expressions.
+ */
+ ret = lttng_trigger_generate_bytecode(trigger, &cmd_creds);
+ if (ret != LTTNG_OK) {
+ 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.
+ */