From: Ondřej Surý <ondrej@isc.org>
Date: Tue, 14 Jul 2020 08:52:02 +0000 (+0200)
Subject: Disable calling DllMain() on thread creation/destruction
X-Git-Tag: v9.17.11~40^2~2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4bde4f050be7365b972f8a5511138888c3367b99;p=thirdparty%2Fbind9.git

Disable calling DllMain() on thread creation/destruction

Disables the DLL_THREAD_ATTACH and DLL_THREAD_DETACH notifications for
the specified dynamic-link library (DLL).  This can reduce the size of
the working set for some applications.
---

diff --git a/lib/isc/win32/DLLMain.c b/lib/isc/win32/DLLMain.c
index 91f14e7b009..3acfee4f467 100644
--- a/lib/isc/win32/DLLMain.c
+++ b/lib/isc/win32/DLLMain.c
@@ -19,27 +19,32 @@ __declspec(dllexport) BOOL WINAPI
 	DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) {
 	switch (fdwReason) {
 	/*
-	 * The DLL is loading due to process
-	 * initialization or a call to LoadLibrary.
+	 * The DLL is loading due to process initialization or a call to
+	 * LoadLibrary.
 	 */
 	case DLL_PROCESS_ATTACH:
-		break;
-
-	/* The attached process creates a new thread.  */
-	case DLL_THREAD_ATTACH:
-		break;
-
-	/* The thread of the attached process terminates. */
-	case DLL_THREAD_DETACH:
+		/*
+		 * Disable DllMain() invocation on Thread creation/destruction
+		 */
+		DisableThreadLibraryCalls(hinstDLL);
 		break;
 
 	/*
-	 * The DLL is unloading from a process due to
-	 * process termination or a call to FreeLibrary.
+	 * The DLL is unloading from a process due to process
+	 * termination or a call to FreeLibrary.
 	 */
 	case DLL_PROCESS_DETACH:
 		break;
 
+	case DLL_THREAD_ATTACH:
+	case DLL_THREAD_DETACH:
+		/*
+		 * Calling DllMain when attaching/detaching process has been
+		 * disabled.
+		 */
+		INSIST(0);
+		break;
+
 	default:
 		break;
 	}