lua: Fix memory handling

1 files changed, 35 insertions, 3 deletions

diff --git a/lua/filter.c b/lua/filter.c
index f4de8f1f..220bdcf1 100644
--- a/lua/filter.c
+++ b/lua/filter.c
@@ -95,7 +95,41 @@ static const char *lua_interpret_reader(lua_State *L UNUSED, void *ud, size_t *s
   return out;
 }
 
-struct f_val lua_interpret(struct lua_filter_chunk *chunk, struct rte **e, struct rta **a UNUSED, struct ea_list **ea UNUSED, struct linpool *lp, int flags UNUSED) {
+static inline void f_rte_cow(struct rte **e, struct rta **a)
+{
+  if (!((*e)->flags & REF_COW))
+    return;
+
+  *e = rte_do_cow(*e);
+}
+
+static void
+f_rta_cow(struct rte **e, struct rta **old_rta, struct linpool *lp)
+{
+  if (!rta_is_cached((*e)->attrs))
+    return;
+
+  /* Prepare to modify rte */
+  f_rte_cow(e, old_rta);
+
+  /* Store old rta to free it later, it stores reference from rte_cow() */
+  *old_rta = (*e)->attrs;
+
+  /*
+   * Get shallow copy of rta. Fields eattrs and nexthops of rta are shared
+   * with f_old_rta (they will be copied when the cached rta will be obtained
+   * at the end of f_run()), also the lock of hostentry is inherited (we
+   * suppose hostentry is not changed by filters).
+   */
+  (*e)->attrs = rta_do_cow((*e)->attrs, lp);
+
+  /* Re-cache the ea_list */
+  /* f_cache_eattrs(); */
+}
+
+struct f_val lua_interpret(struct lua_filter_chunk *chunk, struct rte **e, struct rta **a, struct ea_list **ea UNUSED, struct linpool *lp, int flags UNUSED) {
+  f_rta_cow(e, a, lp);
+
   lua_State *L = luaB_getstate();
 
   lua_bird_state *lbs = luaB_init(L, lp);
@@ -118,8 +152,6 @@ struct f_val lua_interpret(struct lua_filter_chunk *chunk, struct rte **e, struc
     out = F_VAL(T_RETURN, i, F_ERROR);
   }
 
-  *ea = (*e)->attrs->eattrs;
-
   luaB_close(L);
   return out;
 }