unit: deduce following unit value dynamically instead of statically, to avoid dangling pointers

1 files changed, 5 insertions, 3 deletions

diff --git a/src/unit.h b/src/unit.h
index f1171270f8..34e86d1086 100644
--- a/src/unit.h
+++ b/src/unit.h
@@ -176,9 +176,6 @@ struct Meta {
         /* GC queue */
         LIST_FIELDS(Meta, gc_queue);
 
-        /* This follows another unit in state */
-        Unit *following;
-
         /* Used during GC sweeps */
         unsigned gc_marker;
 
@@ -313,6 +310,9 @@ struct UnitVTable {
         /* Called for each message received on the bus */
         DBusHandlerResult (*bus_message_handler)(Unit *u, DBusConnection *c, DBusMessage *message);
 
+        /* Return the unit this unit is following */
+        Unit *(*following)(Unit *u);
+
         /* This is called for each unit type and should be used to
          * enumerate existing devices and load them. However,
          * everything that is loaded here should still stay in
@@ -475,6 +475,8 @@ bool unit_need_daemon_reload(Unit *u);
 
 void unit_reset_maintenance(Unit *u);
 
+Unit *unit_following(Unit *u);
+
 const char *unit_type_to_string(UnitType i);
 UnitType unit_type_from_string(const char *s);