From b9cb252b33b0b026acc0af48ee63e2a8d5c5ac6d Mon Sep 17 00:00:00 2001
From: mingkuang <mingkuang@live.com>
Date: Fri, 20 Sep 2024 00:18:34 +0800
Subject: [PATCH] =?UTF-8?q?Opt,=20=E6=96=B0=E5=A2=9E=5F=5FYY=5FThunks=5FDi?=
 =?UTF-8?q?sable=5FRreload=5FDlls=E5=BC=B1=E7=AC=A6=E5=8F=B7=EF=BC=8C?=
 =?UTF-8?q?=E6=8E=A7=E5=88=B6=E9=A2=84=E5=8A=A0=E8=BD=BD=E7=8A=B6=E6=80=81?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/Build.cmd                 |  2 +-
 src/Thunks/YY_Thunks.h        | 28 +++++++++++++++++++++-------
 src/YY-Thunks.UnitTest/weak.c |  2 ++
 3 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/Build.cmd b/src/Build.cmd
index 58d20a7..392ba08 100644
--- a/src/Build.cmd
+++ b/src/Build.cmd
@@ -140,7 +140,7 @@ goto:eof
 
 :: FixObj "XXX\YY_Thunks_for_Vista.obj" 1.def+2.def
 :FixObj
-LibMaker.exe FixObj %1 /WeakExternFix:__security_cookie=%PointType% /WeakExternFix:__acrt_atexit_table=%PointType% /WeakExternFix:__pfnDllMainCRTStartupForYY_Thunks=%PointType%
+LibMaker.exe FixObj %1 /WeakExternFix:__security_cookie=%PointType% /WeakExternFix:__acrt_atexit_table=%PointType% /WeakExternFix:__pfnDllMainCRTStartupForYY_Thunks=%PointType% /WeakExternFix:__YY_Thunks_Disable_Rreload_Dlls=4
 if %ErrorLevel% NEQ 0 exit /b %ErrorLevel%
 if "%2"=="" goto:eof
 set DEF_FILES=%2
diff --git a/src/Thunks/YY_Thunks.h b/src/Thunks/YY_Thunks.h
index 28d4ff7..1060eca 100644
--- a/src/Thunks/YY_Thunks.h
+++ b/src/Thunks/YY_Thunks.h
@@ -104,6 +104,17 @@ else
 */
 EXTERN_C const UINT64 __YY_Thunks_Installed = YY_Thunks_Target;
 
+/*
+导出一个外部弱符号，指示当前是否关闭DLL预载（默认开启DLL预载）。
+警告：关闭DLL预载虽然可以提升初始化速度，但是这可能带来死锁问题。目前已知的有：
+  1. locale锁/LoadDll锁交叉持锁产生死锁（https://github.com/Chuyu-Team/YY-Thunks/issues/7）
+  2. thread safe init锁/LoadDll锁交叉持锁产生死锁
+
+// 如果需要关闭DLL预载，那么再任意位置定义如下变量即可：
+EXTERN_C const BOOL __YY_Thunks_Disable_Rreload_Dlls = TRUE;
+*/
+EXTERN_C extern BOOL __YY_Thunks_Disable_Rreload_Dlls /* = FALSE*/;
+
 // 从DllMain缓存RtlDllShutdownInProgress状态，规避退出时调用RtlDllShutdownInProgress。
 // 0：缓存无效
 // 1：模块正常卸载
@@ -642,14 +653,17 @@ static ThunksInitStatus __cdecl _YY_initialize_winapi_thunks(ThunksInitStatus _s
         // 后续过程已经可以线程安全执行了，所以我们立即解锁，避免其他线程过于长时间的等待
         InterlockedExchange((volatile LONG*)&s_eThunksStatus, LONG(_sInitStatus));
 
-        /*
-         * https://github.com/Chuyu-Team/YY-Thunks/issues/7
-         * 为了避免 try_get 系列函数竞争 DLL load锁，因此我们将所有被Thunk的API都预先加载完毕。
-         */
-        for (auto p = (InitFunType*)__YY_THUNKS_INIT_FUN_START; p != (InitFunType*)__YY_THUNKS_INIT_FUN_END; ++p)
+        if (!__YY_Thunks_Disable_Rreload_Dlls)
         {
-            if (auto pInitFun = *p)
-                pInitFun();
+            /*
+             * https://github.com/Chuyu-Team/YY-Thunks/issues/7
+             * 为了避免 try_get 系列函数竞争 DLL load锁，因此我们将所有被Thunk的API都预先加载完毕。
+             */
+            for (auto p = (InitFunType*)__YY_THUNKS_INIT_FUN_START; p != (InitFunType*)__YY_THUNKS_INIT_FUN_END; ++p)
+            {
+                if (auto pInitFun = *p)
+                    pInitFun();
+            }
         }
 
         return _sInitStatus;
diff --git a/src/YY-Thunks.UnitTest/weak.c b/src/YY-Thunks.UnitTest/weak.c
index 0b33576..d46c421 100644
--- a/src/YY-Thunks.UnitTest/weak.c
+++ b/src/YY-Thunks.UnitTest/weak.c
@@ -2,3 +2,5 @@
 const void* __acrt_atexit_table;
 
 const void* __pfnDllMainCRTStartupForYY_Thunks;
+
+const void* __YY_Thunks_Disable_Rreload_Dlls;