+
+/*************************************************
+* Walk tree recursively and execute function *
+*************************************************/
+
+/*
+Arguments:
+ p root of the tree
+ f function to execute for each name-value-pair
+ ctx context data for f
+*/
+
+void
+tree_walk(tree_node *p, void (*f)(uschar*, uschar*, void*), void *ctx)
+{
+if (!p) return;
+f(p->name, p->data.ptr, ctx);
+tree_walk(p->left, f, ctx);
+tree_walk(p->right, f, ctx);
+}
+
+
+
+/* Add a node to a tree, ignoring possibility of duplicates */
+
+static void
+tree_add_var(uschar * name, uschar * val, void * ctx)
+{
+tree_node ** root = ctx;
+tree_node * node = store_get(sizeof(tree_node) + Ustrlen(name), is_tainted(name));
+Ustrcpy(node->name, name);
+node->data.ptr = val;
+(void) tree_insertnode(root, node);
+}
+
+/* Duplicate a tree */
+
+void
+tree_dup(tree_node ** dstp, tree_node * src)
+{
+tree_walk(src, tree_add_var, dstp);
+}
+
+
+