From Balint Reczey

Fix for https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=2453

The patch fixes the problem by extending the original "outstanding stuff"
approach.

Now the pointer itself won't be NULLified, instead we track the pointers with
their expiry state in structs in the outstanding_stuff list.
The Lua objects refers to those structs instead of the actual pointers and
checks the expiry state of the pointers before accessing them.
The pointers are marked expired when the dissection of the frame is finished
and the allocated struct is freed by Lua's garbage collector.

If the garbage collector hits the struct when it holds a not expired pointer,
it marks it as expired (that means we don't have any object in Lua referring to
the pointer) and the struct will be freed at the end of the dissection of the
frame.

this is for the 1.0 branch


svn path=/trunk/; revision=25845

1 files changed, 66 insertions, 28 deletions

diff --git a/epan/wslua/wslua_tree.c b/epan/wslua/wslua_tree.c
index cc0a166011..edfde1e9b7 100644
--- a/epan/wslua/wslua_tree.c
+++ b/epan/wslua/wslua_tree.c
@@ -4,6 +4,7 @@
  * Wireshark's interface to the Lua Programming Language
  *
  * (c) 2006, Luis E. Garcia Ontanon <luis.ontanon@gmail.com>
+ * (c) 2008, Balint Reczey <balint.reczey@ericsson.com>
  *
  * $Id$
  *
@@ -33,22 +34,16 @@
 
 static gint wslua_ett = -1;
 
-static GPtrArray* outstanding_stuff = NULL;
+static GPtrArray* outstanding_TreeItem = NULL;
 
-#define PUSH_TREEITEM(L,i) g_ptr_array_add(outstanding_stuff,push_TreeItem(L,i))
+#define PUSH_TREEITEM(L,i) {g_ptr_array_add(outstanding_TreeItem,i);pushTreeItem(L,i);}
 
-void* push_TreeItem(lua_State*L, TreeItem t) {
-    void** p = (void**)pushTreeItem(L,t);
-    g_ptr_array_add(outstanding_stuff,p);
-	return p;
+TreeItem* push_TreeItem(lua_State*L, TreeItem t) {
+    g_ptr_array_add(outstanding_TreeItem,t);
+    return pushTreeItem(L,t);
 }
 
-void clear_outstanding_trees(void) {
-    while (outstanding_stuff->len) {
-        void** p = (void**)g_ptr_array_remove_index_fast(outstanding_stuff,0);
-        *p = NULL;
-    }
-}
+CLEAR_OUTSTANDING(TreeItem, expired, TRUE)
 
 WSLUA_CLASS_DEFINE(TreeItem,NOP,NOP);
 /* TreeItems represent information in the packet-details pane.
@@ -67,6 +62,11 @@ static int TreeItem_add_item_any(lua_State *L, gboolean little_endian) {
     if (!tree_item) {
         return luaL_error(L,"not a TreeItem!");
     }
+    if (tree_item->expired) {
+        luaL_error(L,"expired TreeItem");
+        return 0;
+    }
+
     if (! ( field = shiftProtoField(L,1) ) ) {
         if (( proto = shiftProto(L,1) )) {
             hfid = proto->hfid;
@@ -83,7 +83,8 @@ static int TreeItem_add_item_any(lua_State *L, gboolean little_endian) {
 
     if (!tvbr) {
         tvbr = ep_alloc(sizeof(struct _wslua_tvbrange));
-        tvbr->tvb = lua_tvb;
+        tvbr->tvb = ep_alloc(sizeof(struct _wslua_tvb));
+        tvbr->tvb->ws_tvb = lua_tvb;
         tvbr->offset = 0;
         tvbr->len = 0;
     }
@@ -92,7 +93,7 @@ static int TreeItem_add_item_any(lua_State *L, gboolean little_endian) {
         if (lua_gettop(L)) {
             switch(type) {
                 case FT_PROTOCOL:
-                    item = proto_tree_add_item(tree_item->tree,hfid,tvbr->tvb,tvbr->offset,tvbr->len,FALSE);
+                    item = proto_tree_add_item(tree_item->tree,hfid,tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len,FALSE);
                     lua_pushnumber(L,0);
                     lua_insert(L,1);
                     break;
@@ -101,35 +102,35 @@ static int TreeItem_add_item_any(lua_State *L, gboolean little_endian) {
                 case FT_UINT24:
                 case FT_UINT32:
                 case FT_FRAMENUM:
-                    item = proto_tree_add_uint(tree_item->tree,hfid,tvbr->tvb,tvbr->offset,tvbr->len,(guint32)luaL_checknumber(L,1));
+                    item = proto_tree_add_uint(tree_item->tree,hfid,tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len,(guint32)luaL_checknumber(L,1));
                     break;
                 case FT_INT8:
                 case FT_INT16:
                 case FT_INT24:
                 case FT_INT32:
-                    item = proto_tree_add_int(tree_item->tree,hfid,tvbr->tvb,tvbr->offset,tvbr->len,(gint32)luaL_checknumber(L,1));
+                    item = proto_tree_add_int(tree_item->tree,hfid,tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len,(gint32)luaL_checknumber(L,1));
                     break;
                 case FT_FLOAT:
-                    item = proto_tree_add_float(tree_item->tree,hfid,tvbr->tvb,tvbr->offset,tvbr->len,(float)luaL_checknumber(L,1));
+                    item = proto_tree_add_float(tree_item->tree,hfid,tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len,(float)luaL_checknumber(L,1));
                     break;
                 case FT_DOUBLE:
-                    item = proto_tree_add_double(tree_item->tree,hfid,tvbr->tvb,tvbr->offset,tvbr->len,(double)luaL_checknumber(L,1));
+                    item = proto_tree_add_double(tree_item->tree,hfid,tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len,(double)luaL_checknumber(L,1));
                     break;
                 case FT_STRING:
                 case FT_STRINGZ:
-                    item = proto_tree_add_string(tree_item->tree,hfid,tvbr->tvb,tvbr->offset,tvbr->len,luaL_checkstring(L,1));
+                    item = proto_tree_add_string(tree_item->tree,hfid,tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len,luaL_checkstring(L,1));
                     break;
                 case FT_BYTES:
-                    item = proto_tree_add_bytes(tree_item->tree,hfid,tvbr->tvb,tvbr->offset,tvbr->len, (const guint8*) luaL_checkstring(L,1));
+                    item = proto_tree_add_bytes(tree_item->tree,hfid,tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len, (const guint8*) luaL_checkstring(L,1));
                     break;
                 case FT_UINT64:
-                    item = proto_tree_add_uint64(tree_item->tree,hfid,tvbr->tvb,tvbr->offset,tvbr->len,(guint64)luaL_checknumber(L,1));
+                    item = proto_tree_add_uint64(tree_item->tree,hfid,tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len,(guint64)luaL_checknumber(L,1));
                     break;
                 case FT_INT64:
-                    item = proto_tree_add_int64(tree_item->tree,hfid,tvbr->tvb,tvbr->offset,tvbr->len,(gint64)luaL_checknumber(L,1));
+                    item = proto_tree_add_int64(tree_item->tree,hfid,tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len,(gint64)luaL_checknumber(L,1));
                     break;
                 case FT_IPv4:
-                    item = proto_tree_add_ipv4(tree_item->tree,hfid,tvbr->tvb,tvbr->offset,tvbr->len,*((guint32*)(checkAddress(L,1)->data)));
+                    item = proto_tree_add_ipv4(tree_item->tree,hfid,tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len,*((guint32*)(checkAddress(L,1)->data)));
                     break;
                 case FT_ETHER:
                 case FT_UINT_BYTES:
@@ -145,7 +146,7 @@ static int TreeItem_add_item_any(lua_State *L, gboolean little_endian) {
             lua_remove(L,1);
 
         } else {
-            item = proto_tree_add_item(tree_item->tree, hfid, tvbr->tvb, tvbr->offset, tvbr->len, little_endian);
+            item = proto_tree_add_item(tree_item->tree, hfid, tvbr->tvb->ws_tvb, tvbr->offset, tvbr->len, little_endian);
         }
         
         if ( lua_gettop(L) ) {
@@ -161,7 +162,7 @@ static int TreeItem_add_item_any(lua_State *L, gboolean little_endian) {
         if (lua_gettop(L)) {
             const gchar* s = lua_tostring(L,1);
 
-            item = proto_tree_add_text(tree_item->tree, tvbr->tvb, tvbr->offset, tvbr->len,"%s",s);
+            item = proto_tree_add_text(tree_item->tree, tvbr->tvb->ws_tvb, tvbr->offset, tvbr->len,"%s",s);
             lua_remove(L,1);
         }
     } else {
@@ -182,9 +183,10 @@ static int TreeItem_add_item_any(lua_State *L, gboolean little_endian) {
     }
     
 
-	tree_item = ep_alloc(sizeof(struct _wslua_treeitem));
+	tree_item = g_malloc(sizeof(struct _wslua_treeitem));
 	tree_item->item = item;
 	tree_item->tree = proto_item_add_subtree(item,ett > 0 ? ett : wslua_ett);
+	tree_item->expired = FALSE;
 
     PUSH_TREEITEM(L,tree_item);
     
@@ -231,6 +233,11 @@ WSLUA_METHOD TreeItem_append_text(lua_State *L) {
     const gchar* s;
     
     if (ti) {
+        if (ti->expired) {
+            luaL_error(L,"expired TreeItem");
+            return 0;
+        }
+
         s = luaL_checkstring(L,2);
         proto_item_append_text(ti->item,"%s",s);
     }
@@ -246,7 +253,11 @@ WSLUA_METHOD TreeItem_set_expert_flags(lua_State *L) {
 	int severity = luaL_optint(L,3,PI_CHAT);
 
     if ( ti && ti->item ) {
-            proto_item_set_expert_flags(ti->item,group,severity);
+        if (ti->expired) {
+            luaL_error(L,"expired TreeItem");
+            return 0;
+        }
+        proto_item_set_expert_flags(ti->item,group,severity);
     }
 
     return 0;
@@ -263,6 +274,10 @@ WSLUA_METHOD TreeItem_add_expert_info(lua_State *L) {
 	const gchar* str = luaL_optstring(L,4,"Expert Info");
 	
     if ( ti && ti->item ) {
+        if (ti->expired) {
+            luaL_error(L,"expired TreeItem");
+            return 0;
+        }
         expert_add_info_format(lua_pinfo, ti->item, group, severity, "%s", str);
     }
     
@@ -273,6 +288,10 @@ WSLUA_METHOD TreeItem_set_generated(lua_State *L) {
 	/* marks the TreeItem as a generated field (with data infered but not contained in the packet). */
     TreeItem ti = checkTreeItem(L,1);
     if (ti) {
+        if (ti->expired) {
+            luaL_error(L,"expired TreeItem");
+            return 0;
+        }
         PROTO_ITEM_SET_GENERATED(ti->item);
     }
     return 0;
@@ -283,11 +302,29 @@ WSLUA_METHOD TreeItem_set_hidden(lua_State *L) {
 	/* should not be used */
     TreeItem ti = checkTreeItem(L,1);
     if (ti) {
+        if (ti->expired) {
+            luaL_error(L,"expired TreeItem");
+            return 0;
+        }
         PROTO_ITEM_SET_HIDDEN(ti->item);
     }
     return 0;
 }
 
+WSLUA_METAMETHOD TreeItem_gc(lua_State* L) {
+    TreeItem ti = checkTreeItem(L,1);
+
+    if (!ti) return 0;
+    
+    if (!ti->expired)
+        ti->expired = TRUE;
+    else
+        g_free(ti);
+
+    return 0;
+
+}
+
 static const luaL_reg TreeItem_methods[] = {
     {"add",       TreeItem_add},
     {"add_le",       TreeItem_add_le},
@@ -300,6 +337,7 @@ static const luaL_reg TreeItem_methods[] = {
     { NULL, NULL }
 };
 static const luaL_reg TreeItem_meta[] = {
+    {"__gc", TreeItem_gc},
     { NULL, NULL }
 };
 
@@ -309,7 +347,7 @@ int TreeItem_register(lua_State *L) {
 	gint* etts[] = { &wslua_ett };
 	
 	WSLUA_REGISTER_CLASS(TreeItem);    
-    outstanding_stuff = g_ptr_array_new();
+	outstanding_TreeItem = g_ptr_array_new();
 	
 	proto_register_subtree_array(etts,1);