1 files changed, 61 insertions, 0 deletions
diff --git a/src/vm/notifyexternals.cpp b/src/vm/notifyexternals.cpp
new file mode 100644
index 0000000000..df1cce4e5b
--- /dev/null
+++ b/src/vm/notifyexternals.cpp
@@ -0,0 +1,61 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+// ===========================================================================
+// File: notifyexternals.cpp
+// 
+
+// ===========================================================================
+
+
+#include "common.h"
+
+#include "excep.h"
+#include "interoputil.h"
+#include "comcache.h"
+
+#include "notifyexternals.h"
+#include "mdaassistants.h"
+
+// On some platforms, we can detect whether the current thread holds the loader
+// lock.  It is unsafe to execute managed code when this is the case
+BOOL ShouldCheckLoaderLock(BOOL fForMDA /*= TRUE*/)
+{
+    CONTRACTL
+    {
+        NOTHROW;
+        GC_NOTRIGGER;
+        MODE_ANY;
+        SO_TOLERANT;
+    }
+    CONTRACTL_END;
+    
+#ifdef FEATURE_CORESYSTEM
+    // CoreSystem does not support this.
+    return FALSE;
+#else
+    // Because of how C++ generates code, we must use default initialization to
+    // 0 here.  Any explicit initialization will result in thread-safety problems.
+    static BOOL fInited;
+    static BOOL fShouldCheck;
+    static BOOL fShouldCheck_ForMDA;
+
+    if (VolatileLoad(&fInited) == FALSE)
+    {
+        fShouldCheck_ForMDA = FALSE;
+
+        fShouldCheck = AuxUlibInitialize();      // may fail
+
+#ifdef MDA_SUPPORTED
+        if (fShouldCheck)
+        {
+            MdaLoaderLock* pProbe = MDA_GET_ASSISTANT(LoaderLock);
+            if (pProbe)
+                fShouldCheck_ForMDA = TRUE;
+        }
+#endif // MDA_SUPPORTED
+        VolatileStore(&fInited, TRUE);
+    }
+    return (fForMDA ? fShouldCheck_ForMDA : fShouldCheck);
+#endif // FEATURE_CORESYSTEM
+}