From 00283a7267e7c1d4069146fe16f5c14d4e4c08de Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Tue, 16 Feb 2016 19:35:54 -0500
Subject: [PATCH] Fix a race condition where PltCloseThread was called before
 the thread was inserted into the list

---
 limelight-common/Platform.c        | 26 ++++++++++++++++++++++----
 limelight-common/PlatformThreads.h | 18 ++++++++++--------
 2 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/limelight-common/Platform.c b/limelight-common/Platform.c
index 0037e16..7611754 100644
--- a/limelight-common/Platform.c
+++ b/limelight-common/Platform.c
@@ -40,6 +40,9 @@ void* ThreadProc(void* context) {
     ctx->thread->next = thread_head;
     thread_head = ctx->thread;
     PltUnlockMutex(&thread_list_lock);
+    
+    // Signal the event since the thread is now inserted
+    PltSetEvent(&ctx->thread->insertedEvent);
 
     ctx->entry(ctx->context);
 
@@ -164,6 +167,8 @@ void PltCloseThread(PLT_THREAD* thread) {
     }
 
     PltUnlockMutex(&thread_list_lock);
+    
+    PltCloseEvent(&thread->insertedEvent);
 
 #if defined(LC_WINDOWS)
     CloseHandle(thread->termRequested);
@@ -195,36 +200,49 @@ int PltCreateThread(ThreadEntry entry, void* context, PLT_THREAD* thread) {
     ctx->context = context;
     ctx->thread = thread;
     
+    err = PltCreateEvent(&thread->insertedEvent);
+    if (err != 0) {
+        free(ctx);
+        return err;
+    }
+    
     thread->cancelled = 0;
 
 #if defined(LC_WINDOWS)
     {
         thread->termRequested = CreateEventEx(NULL, NULL, CREATE_EVENT_MANUAL_RESET, EVENT_ALL_ACCESS);
         if (thread->termRequested == NULL) {
+            PltCloseEvent(&thread->insertedEvent);
             free(ctx);
             return -1;
         }
 
         thread->handle = CreateThread(NULL, 0, ThreadProc, ctx, 0, &thread->tid);
         if (thread->handle == NULL) {
+            PltCloseEvent(&thread->insertedEvent);
             CloseHandle(thread->termRequested);
             free(ctx);
             return -1;
         }
-        else {            
-            err = 0;
-        }
     }
 #else
     {
         err = pthread_create(&thread->thread, NULL, ThreadProc, ctx);
         if (err != 0) {
+            PltCloseEvent(&thread->insertedEvent);
             free(ctx);
+            return err;
         }
     }
 #endif
+    
+    // We shouldn't get this far with an error
+    LC_ASSERT(err == 0);
+    
+    // Wait for the thread to be started and inserted into the active threads list
+    PltWaitForEvent(&thread->insertedEvent);
 
-    return err;
+    return 0;
 }
 
 int PltCreateEvent(PLT_EVENT* event) {
diff --git a/limelight-common/PlatformThreads.h b/limelight-common/PlatformThreads.h
index ee01cae..98a6d9d 100644
--- a/limelight-common/PlatformThreads.h
+++ b/limelight-common/PlatformThreads.h
@@ -6,29 +6,31 @@
 typedef void(*ThreadEntry)(void* context);
 
 #if defined(LC_WINDOWS)
+typedef HANDLE PLT_MUTEX;
+typedef HANDLE PLT_EVENT;
 typedef struct _PLT_THREAD {
     HANDLE handle;
     int cancelled;
     DWORD tid;
     HANDLE termRequested;
+    PLT_EVENT insertedEvent;
 
     struct _PLT_THREAD* next;
 } PLT_THREAD;
-typedef HANDLE PLT_MUTEX;
-typedef HANDLE PLT_EVENT;
 #elif defined (LC_POSIX)
-typedef struct _PLT_THREAD {
-    pthread_t thread;
-    int cancelled;
-
-    struct _PLT_THREAD* next;
-} PLT_THREAD;
 typedef pthread_mutex_t PLT_MUTEX;
 typedef struct _PLT_EVENT {
     pthread_mutex_t mutex;
     pthread_cond_t cond;
     int signalled;
 } PLT_EVENT;
+typedef struct _PLT_THREAD {
+    pthread_t thread;
+    int cancelled;
+    PLT_EVENT insertedEvent;
+
+    struct _PLT_THREAD* next;
+} PLT_THREAD;
 #else
 #error Unsupported platform
 #endif