From 5aa8723120f3421599a9af4edbf91f9364bcfea7 Mon Sep 17 00:00:00 2001
From: Lucy <lucy@absolucy.moe>
Date: Sat, 26 Oct 2024 05:43:30 -0400
Subject: [PATCH] Add isolated lua states

---
 src/lib.rs                   |  5 +++--
 src/state/library/global.rs  | 15 ++++++++++-----
 src/state/mod.rs             | 12 +++++++++++-
 src/value/conversion/into.rs |  8 +++++++-
 4 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index bb8bc03..2b2d6c7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -8,8 +8,9 @@ pub(crate) mod wrappers;
 
 pub use state::{
     awaken, call_function, clear_execution_limit, clear_ref_userdata, collect_garbage, get_globals,
-    get_traceback, kill_sleeping_thread, kill_state, kill_yielded_thread, list_threads, load,
-    new_state, resume, set_execution_limit_millis, set_execution_limit_secs, set_usr,
+    get_traceback, is_isolated, kill_sleeping_thread, kill_state, kill_yielded_thread,
+    list_threads, load, new_state, resume, set_execution_limit_millis, set_execution_limit_secs,
+    set_usr,
 };
 
 pub use wrappers::{
diff --git a/src/state/library/global.rs b/src/state/library/global.rs
index 7b6d2e7..f9dc228 100644
--- a/src/state/library/global.rs
+++ b/src/state/library/global.rs
@@ -18,9 +18,8 @@ impl LuaModule for GlobalModule {
     fn create_items<'lua>(&self, lua: &'lua Lua) -> LuaResult<Vec<(&str, LuaValue<'lua>)>> {
         let id = self.0;
         let id1 = self.0;
-        Ok(vec![
-            ("dm", (&DmModule as &dyn LuaModule).into_lua(lua)?),
-            ("list", (&ListModule as &dyn LuaModule).into_lua(lua)?),
+        let isolate = lua.named_registry_value::<bool>("isolated")?;
+        let mut items = vec![
             (
                 "loadstring",
                 Function::wrap(|lua, code: String| {
@@ -29,7 +28,6 @@ impl LuaModule for GlobalModule {
                 })
                 .into_lua(lua)?,
             ),
-            ("pointer", (&PointerModule as &dyn LuaModule).into_lua(lua)?),
             (
                 "sleep",
                 unsafe { lua.create_c_function(sleep) }.map(LuaValue::Function)?,
@@ -40,8 +38,15 @@ impl LuaModule for GlobalModule {
             ),
             ("_exec", (&ExecModule as &dyn LuaModule).into_lua(lua)?),
             ("_state_id", LuaValue::Integer(id)),
-        ])
+        ];
+        if !isolate {
+            items.push(("dm", (&DmModule as &dyn LuaModule).into_lua(lua)?));
+            items.push(("list", (&ListModule as &dyn LuaModule).into_lua(lua)?));
+            items.push(("pointer", (&PointerModule as &dyn LuaModule).into_lua(lua)?));
+        }
+        Ok(items)
     }
+
     fn create_metamethods<'lua>(
         &self,
         _: &'lua Lua,
diff --git a/src/state/mod.rs b/src/state/mod.rs
index 2fae62e..395e535 100644
--- a/src/state/mod.rs
+++ b/src/state/mod.rs
@@ -38,8 +38,10 @@ thread_local! {
 
 #[map_statics(mut STATES)]
 #[byond_fn]
-pub fn new_state() -> ByondResult<usize> {
+pub fn new_state(isolate: Option<bool>) -> ByondResult<usize> {
     let lua: Lua = Lua::new();
+    lua.set_named_registry_value("isolated", isolate.unwrap_or(false))
+        .map_err(ByondError::boxed)?;
     let new_state_index = states.iter().position(Option::is_none).unwrap_or_else(|| {
         states.push(None);
         states.len() - 1
@@ -70,6 +72,14 @@ fn get_state(index: usize) -> ByondResult<Rc<Lua>> {
         )))
 }
 
+#[byond_fn]
+pub fn is_isolated(index: usize) -> ByondResult<bool> {
+    get_state(index).and_then(|lua| {
+        lua.named_registry_value("isolated")
+            .map_err(ByondError::boxed)
+    })
+}
+
 #[byond_fn]
 pub fn load(index: usize, code: String, name: Option<String>) -> ByondResult<ByondValue> {
     get_state(index).and_then(|lua| run::load(lua.as_ref(), code, name))
diff --git a/src/value/conversion/into.rs b/src/value/conversion/into.rs
index ef5f818..5c7d3ea 100644
--- a/src/value/conversion/into.rs
+++ b/src/value/conversion/into.rs
@@ -82,6 +82,12 @@ impl<'lua> IntoLua<'lua> for Value {
                 .into_printed_external()?
                 .into_lua(lua);
         };
-        get_or_create_cached_userdata(self, lua)?.into_lua(lua)
+        // If isolated, never allow any sort of userdata to be exposed.
+        let isolate = lua.named_registry_value::<bool>("isolated")?;
+        if isolate {
+            Ok(LuaValue::Nil)
+        } else {
+            get_or_create_cached_userdata(self, lua)?.into_lua(lua)
+        }
     }
 }