From 2b985e277f06a7086025ab292ddb22b5ded89189 Mon Sep 17 00:00:00 2001
From: ame <grantsquires@disroot.org>
Date: Thu, 9 May 2024 10:31:26 -0500
Subject: work on memory saftey

---
 src/thread.c | 42 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 5 deletions(-)

(limited to 'src')

diff --git a/src/thread.c b/src/thread.c
index 441793b..393d3fb 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -13,14 +13,15 @@
 struct thread_info {
     str* function;
     lua_State* L;
-    int return_count;
+    int return_count, done;
     pthread_t tid;
-    pthread_cond_t cond;
     pthread_mutex_t lock;
 };
 
 #include "io.h"
 
+//give the current thread priority to locking thread_lock_lock (fixes race conds)
+pthread_mutex_t thread_priority_lock = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
 pthread_mutex_t thread_lock_lock = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
 larray_t* thread_locks = NULL;
 
@@ -28,6 +29,8 @@ int l_tlock(lua_State* L){
     int idx = luaL_checkinteger(L, 1);
 
     pthread_mutex_lock(&thread_lock_lock);
+    pthread_mutex_lock(&thread_priority_lock);
+    pthread_mutex_unlock(&thread_priority_lock);
     pthread_mutex_t mutex;
     if(thread_locks == NULL) thread_locks = larray_init();
     int i = 0;
@@ -37,9 +40,13 @@ int l_tlock(lua_State* L){
         larray_set(&thread_locks, idx, (void*)mutex);
     } else {
         pthread_mutex_t m = (pthread_mutex_t)thread_locks->arr[i].value;
+        pthread_mutex_lock(&thread_priority_lock);
+    
         pthread_mutex_unlock(&thread_lock_lock);
         pthread_mutex_lock(&m);
         pthread_mutex_lock(&thread_lock_lock);
+
+        pthread_mutex_unlock(&thread_priority_lock);
         thread_locks->arr[i].value = (void*)m;
 
     }
@@ -90,6 +97,7 @@ int l_res(lua_State* L){
 void* handle_thread(void* _args){
   struct thread_info* args = (struct thread_info*)_args;
   lua_State* L = args->L;
+  lua_gc(L, LUA_GCSTOP);
 
   lua_newtable(L);
   int res_idx = lua_gettop(L);
@@ -117,20 +125,37 @@ int l_await(lua_State* L){
     lua_gettable(L, 1);
     struct thread_info* info = lua_touserdata(L, -1);
 
-    pthread_mutex_lock(&info->lock);
+    if(info->L == NULL) p_fatal("thread has already been cleaned");
+    if(!info->done) pthread_mutex_lock(&info->lock);
+    info->done = 1;
 
     for(int i = 0; i != info->return_count; i++){
         int ot = lua_gettop(info->L);
 
         lua_pushvalue(info->L, ot - info->return_count + i);
         i_dcopy(info->L, L, NULL);
-
+        
         lua_settop(info->L, ot);
     }
 
     return info->return_count;
 }
 
+int l_clean(lua_State* L){
+    lua_pushstring(L, "_");
+    lua_gettable(L, 1);
+    struct thread_info* info = lua_touserdata(L, -1);
+    if(info->L != NULL){
+        lua_gc(info->L, LUA_GCRESTART);
+        lua_gc(info->L, LUA_GCCOLLECT);
+        lua_close(info->L);
+        info->L = NULL;
+        pthread_mutex_destroy(&info->lock);
+        free(info);
+    }
+    return 0;
+}
+
 int l_async(lua_State* oL){
    lua_State* L = luaL_newstate(); 
 
@@ -142,7 +167,6 @@ int l_async(lua_State* oL){
 
   struct thread_info* args = calloc(1, sizeof * args);
   args->L = L;
-  args->cond = (pthread_cond_t)PTHREAD_COND_INITIALIZER;
   args->lock = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
   pthread_mutex_lock(&args->lock);
   args->return_count = 0;
@@ -157,7 +181,15 @@ int l_async(lua_State* oL){
   lua_newtable(oL);
   int res_idx = lua_gettop(oL);
   luaI_tsetcf(oL, res_idx, "await", l_await);
+  luaI_tsetcf(oL, res_idx, "clean", l_clean);
   luaI_tsetlud(oL, res_idx, "_", args);
+
+  lua_newtable(oL);
+  int meta_idx = lua_gettop(oL);
+  luaI_tsetcf(oL, meta_idx, "__gc", l_clean);
+
+  lua_pushvalue(oL, meta_idx);
+  lua_setmetatable(oL, res_idx);
   lua_pushvalue(oL, res_idx);
   return 1;
 }
-- 
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