dthreads: add dt_set_destructor() function

src/knot/server/dthreads.c

@@ -704,6 +704,23 @@ int dt_setaffinity(dthread_t *thread, unsigned* cpu_id, size_t cpu_count)
 	return KNOT_EOK;
 }
 
+/*!
+ * \brief Set thread destructor to be called before physical thread termination.
+ *
+ * \param thread Target thread instance
+ * \param destructor Destructor callback.
+ */
+int dt_set_desctructor(dthread_t *thread, runnable_t destructor)
+{
+	if (thread == 0) {
+		return KNOT_EINVAL;
+	}
+
+	thread->destruct = destructor;
+
+	return KNOT_EOK;
+}
+
 int dt_repurpose(dthread_t *thread, runnable_t runnable, void *data)
 {
 	// Check

src/knot/server/dthreads.h

@@ -225,6 +225,14 @@ int dt_stop(dt_unit_t *unit);
  */
 int dt_setaffinity(dthread_t *thread, unsigned* cpu_id, size_t cpu_count);
 
+/*!
+ * \brief Set thread destructor to be called before physical thread termination.
+ *
+ * \param thread Target thread instance
+ * \param destructor Destructor callback.
+ */
+int dt_set_desctructor(dthread_t *thread, runnable_t destructor);
+
 /*!
  * \brief Set thread to execute another runnable.
  *