thread saftey

1 files changed, 24 insertions, 10 deletions

diff --git a/src/thread.c b/src/thread.c
index bb18ad3..1964ad6 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -4,6 +4,7 @@
 #include <unistd.h>

 #include <pthread.h>

 #include <signal.h>

+#include <sys/eventfd.h>

 #include "types/str.h"

 #include "util.h"

 

@@ -17,6 +18,7 @@ struct thread_info {
   int return_count, done;

   pthread_t tid;

   pthread_mutex_t* lock, *ready_lock;

+  pthread_cond_t* cond;

 };

 

 #include "io.h"

@@ -182,9 +184,12 @@ void* handle_thread(void* _args){
   pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);

 #endif

 

-  pthread_detach(args->tid);

   signal(SIGUSR1, _thread_exit_signal);

 

+  pthread_detach(args->tid);

+  //unlock main

+  pthread_mutex_lock(&*args->ready_lock);

+  pthread_cond_signal(&*args->cond);

   pthread_mutex_unlock(&*args->ready_lock);

 

   lua_newtable(L);

@@ -205,7 +210,7 @@ void* handle_thread(void* _args){
   lua_assign_upvalues(L, x);

   lua_pushvalue(L, res_idx);

   lua_call(L, 1, 0);

-  args->tid = 0;

+  args->done = 1;

   pthread_mutex_unlock(&*args->lock);

 

   return NULL;

@@ -216,11 +221,10 @@ int _thread_await(lua_State* L){
   lua_gettable(L, 1);

   struct thread_info* info = lua_touserdata(L, -1);

   if(info->L == NULL) luaI_error(L, -1, "thread was already closed")

+  if(info->tid == 0) luaI_error(L, -2, "thread was killed early")

+

   //maybe error here if tid is zero

-  if(!info->done && info->tid != 0){

-    pthread_mutex_lock(&*info->lock);

-  }

-  info->done = 1;

+  pthread_mutex_lock(&*info->lock);

 

   env_table(info->L, 0);

   luaI_deepcopy(info->L, L, SKIP_LOCALS);

@@ -249,6 +253,7 @@ int _thread_await(lua_State* L){
 

   lua_pushnil(L);

   lua_setglobal(L, "_locals");

+  pthread_mutex_unlock(&*info->lock);

 

   return info->return_count;

 }

@@ -260,14 +265,14 @@ int _thread_clean(lua_State* L){
   if(info != NULL && info->L != NULL){

     luaI_tsetnil(L, 1, "_");

 

-    if(info->tid != 0){

+    if(info->tid != 0 && !info->done){

 #ifdef SUPPORTS_PTHREAD_CANCEL

       pthread_cancel(info->tid);

 #else

       pthread_kill(info->tid, SIGUSR1);

 #endif

     }

-

+ 

     //lua_gc(info->L, LUA_GCRESTART);

     lua_gc(info->L, LUA_GCCOLLECT);

 

@@ -322,20 +327,26 @@ int l_async(lua_State* oL){
   struct thread_info* args = calloc(1, sizeof * args);

   args->L = L;

   args->lock = malloc(sizeof * args->lock);

-  args->ready_lock = malloc(sizeof * args->ready_lock);

   pthread_mutex_init(&*args->lock, NULL);

+  args->ready_lock = malloc(sizeof * args->ready_lock);

   pthread_mutex_init(&*args->ready_lock, NULL);

   args->return_count = 0;

+  args->cond = malloc(sizeof * args->cond);

+  pthread_cond_init(&*args->cond, NULL);

 

   args->function = str_init("");

   lua_pushvalue(oL, 1);

   lua_dump(oL, writer, (void*)args->function, 0);

 

   pthread_mutex_lock(&*args->ready_lock);

+

   pthread_create(&args->tid, NULL, handle_thread, (void*)args);

-  pthread_mutex_lock(&*args->ready_lock);

 

+  pthread_cond_wait(&*args->cond, &*args->ready_lock);

   pthread_mutex_unlock(&*args->ready_lock);

+

+  pthread_cond_destroy(&*args->cond);

+  free(args->cond);

   pthread_mutex_destroy(&*args->ready_lock);

   free(args->ready_lock);

 

@@ -518,6 +529,9 @@ void meta_proxy_gen(lua_State* L, struct thread_buffer *buffer, int meta_idx, in
 int l_buffer_gc(lua_State* L){

   struct thread_buffer *buffer = lua_touserdata(L, 1);

   pthread_mutex_lock(&*buffer->lock);

+  pthread_mutex_unlock(&*buffer->lock);

+  //race condition here, if something can manage to lock the thread between these two lines

+  //add maybe a closing variable thats checked for

   pthread_mutex_destroy(&*buffer->lock);

   free(buffer->lock);