Create a filesystem abstraction layer for CSM and only allow accessing files that are scanned into it. (#5965)

* Load client-side mods into memory before executing them.

This removes the remaining filesystem access that client-sided mods had and it will hopefully make then more secure.

* Lua Virtual filesystem: don't load the files into memory just scan the filenames into memory.

* Fix the issues with backtrace

* fix most of the issues

* fix code style.

* add a comment

1 files changed, 3 insertions, 31 deletions

diff --git a/src/script/common/c_internal.cpp b/src/script/common/c_internal.cpp
index b349f9dd1..0b388e383 100644
--- a/src/script/common/c_internal.cpp
+++ b/src/script/common/c_internal.cpp
@@ -24,37 +24,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 std::string script_get_backtrace(lua_State *L)
 {
-	std::string s;
-	lua_getglobal(L, "debug");
-	if(lua_istable(L, -1)){
-		lua_getfield(L, -1, "traceback");
-		if(lua_isfunction(L, -1)) {
-			lua_call(L, 0, 1);
-			if(lua_isstring(L, -1)){
-				s = lua_tostring(L, -1);
-			}
-		}
-		lua_pop(L, 1);
-	}
-	lua_pop(L, 1);
-	return s;
-}
-
-int script_error_handler(lua_State *L) {
-	lua_getglobal(L, "debug");
-	if (!lua_istable(L, -1)) {
-		lua_pop(L, 1);
-		return 1;
-	}
-	lua_getfield(L, -1, "traceback");
-	if (!lua_isfunction(L, -1)) {
-		lua_pop(L, 2);
-		return 1;
-	}
-	lua_pushvalue(L, 1);
-	lua_pushinteger(L, 2);
-	lua_call(L, 2, 1);
-	return 1;
+	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_BACKTRACE);
+	lua_call(L, 0, 1);
+	return luaL_checkstring(L, -1);
 }
 
 int script_exception_wrapper(lua_State *L, lua_CFunction f)