Lua: Make global variables read-only

This prevents the user from inadvertently overwriting e.g. the session table and then wondering
why it does not work. I'm still not sure about this approach, as it's not 100% secure (the script
can still use raw access to mess with it) and it adds some overhead to any operation referencing
a global variable.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/FbTk/LResource.cc b/src/FbTk/LResource.cc
index 6671b89..d7627c9 100644
--- a/src/FbTk/LResource.cc
+++ b/src/FbTk/LResource.cc
@@ -105,9 +105,13 @@ LResourceManager::LResourceManager(const std::string &root, Lua &l)
     l.checkstack(2);
     lua::stack_sentry s(l);
 
+    l.pushstring(root);
+
     l.getfield(lua::REGISTRYINDEX, make_root);
     l.pushstring(root);
-    l.call(1, 0);
+    l.call(1, 1);
+
+    l.readOnlySet(lua::GLOBALSINDEX);
 }
 
 bool LResourceManager::save(const char *filename, const char *) {