1 files changed, 169 insertions, 0 deletions

diff --git a/src/libs/wcautil/WixToolset.WcaUtil/wcawow64.cpp b/src/libs/wcautil/WixToolset.WcaUtil/wcawow64.cpp
new file mode 100644
index 00000000..8174c43e
--- /dev/null
+++ b/src/libs/wcautil/WixToolset.WcaUtil/wcawow64.cpp
@@ -0,0 +1,169 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+#include "precomp.h"
+
+static HMODULE s_hKernel32;
+static BOOL s_fWow64Initialized;
+static BOOL (*s_pfnDisableWow64)(__out PVOID* );
+static BOOL (*s_pfnRevertWow64)(__in PVOID );
+static BOOL (*s_pfnIsWow64Process) (HANDLE, PBOOL);
+static PVOID s_Wow64FSRevertState;
+static BOOL s_fWow64FSDisabled;
+
+/********************************************************************
+ WcaInitializeWow64() - Initializes the Wow64 API
+
+********************************************************************/
+extern "C" HRESULT WIXAPI WcaInitializeWow64()
+{
+    AssertSz(WcaIsInitialized(), "WcaInitialize() should be called before calling WcaInitializeWow64()");
+    AssertSz(!WcaIsWow64Initialized(), "WcaInitializeWow64() should not be called twice without calling WcaFinalizeWow64()");
+
+    s_fWow64Initialized = FALSE;
+    HRESULT hr = S_OK;
+    s_Wow64FSRevertState = NULL;
+    s_fWow64FSDisabled = false;
+
+    // Test if we have access to the Wow64 API, and store the result in bWow64APIPresent
+    s_hKernel32 = ::GetModuleHandleW(L"kernel32.dll");
+    if (!s_hKernel32)
+    {
+        ExitWithLastError(hr, "failed to get handle to kernel32.dll");
+    }
+
+    // This will test if we have access to the Wow64 API
+    s_pfnIsWow64Process = (BOOL (*)(HANDLE, PBOOL))::GetProcAddress(s_hKernel32, "IsWow64Process");
+    if (NULL != s_pfnIsWow64Process)
+    {
+        s_pfnDisableWow64 = (BOOL (*)(PVOID *))::GetProcAddress(s_hKernel32, "Wow64DisableWow64FsRedirection");
+        // If we fail, log the error but proceed, because we may not need a particular function, or the Wow64 API at all
+        if (!s_pfnDisableWow64)
+        {
+            return S_FALSE;
+        }
+
+        s_pfnRevertWow64 = (BOOL (*)(PVOID))::GetProcAddress(s_hKernel32, "Wow64RevertWow64FsRedirection");
+        if (!s_pfnRevertWow64)
+        {
+            return S_FALSE;
+        }
+
+        if (s_pfnDisableWow64 && s_pfnRevertWow64)
+        {
+            s_fWow64Initialized = TRUE;
+        }
+    }
+    else
+    {
+        return S_FALSE;
+    }
+
+LExit:
+
+    return hr;
+}
+
+/********************************************************************
+ WcaIsWow64Process() - determines if the current process is running 
+                       in WOW
+
+********************************************************************/
+extern "C" BOOL WIXAPI WcaIsWow64Process()
+{
+    BOOL fIsWow64Process = FALSE;
+    if (s_fWow64Initialized)
+    {
+        if (!s_pfnIsWow64Process(GetCurrentProcess(), &fIsWow64Process))
+        {
+            // clear out the value since call failed
+            fIsWow64Process = FALSE;
+        }
+    }
+    return fIsWow64Process;
+}
+
+/********************************************************************
+ WcaIsWow64Initialized() - determines if WcaInitializeWow64() has
+                           been successfully called
+
+********************************************************************/
+extern "C" BOOL WIXAPI WcaIsWow64Initialized()
+{
+    return s_fWow64Initialized;
+}
+
+/********************************************************************
+ WcaDisableWow64FSRedirection() - Disables Wow64 FS Redirection
+
+********************************************************************/
+extern "C" HRESULT WIXAPI WcaDisableWow64FSRedirection()
+{
+    AssertSz(s_fWow64Initialized && s_pfnDisableWow64 != NULL, "WcaDisableWow64FSRedirection() called, but Wow64 API was not initialized");
+
+#ifdef DEBUG
+    AssertSz(!s_fWow64FSDisabled, "You must call WcaRevertWow64FSRedirection() before calling WcaDisableWow64FSRedirection() again");
+#endif
+
+    HRESULT hr = S_OK;
+    if (s_pfnDisableWow64(&s_Wow64FSRevertState))
+    {
+        s_fWow64FSDisabled = TRUE;
+    }
+    else
+    {
+        ExitWithLastError(hr, "Failed to disable WOW64.");
+    }
+
+LExit:
+    return hr;
+}
+
+/********************************************************************
+ WcaRevertWow64FSRedirection() - Reverts Wow64 FS Redirection to its
+                                 pre-disabled state
+
+********************************************************************/
+extern "C" HRESULT WIXAPI WcaRevertWow64FSRedirection()
+{
+    AssertSz(s_fWow64Initialized && s_pfnDisableWow64 != NULL, "WcaRevertWow64FSRedirection() called, but Wow64 API was not initialized");
+
+#ifdef DEBUG
+    AssertSz(s_fWow64FSDisabled, "You must call WcaDisableWow64FSRedirection() before calling WcaRevertWow64FSRedirection()");
+#endif
+
+    HRESULT hr = S_OK;
+    if (s_pfnRevertWow64(s_Wow64FSRevertState))
+    {
+        s_fWow64FSDisabled = FALSE;
+    }
+    else
+    {
+        ExitWithLastError(hr, "Failed to revert WOW64.");
+    }
+
+LExit:
+    return hr;
+}
+
+/********************************************************************
+ WcaFinalizeWow64() - Cleans up after Wow64 API Initialization
+
+********************************************************************/
+extern "C" HRESULT WIXAPI WcaFinalizeWow64()
+{
+    if (s_fWow64FSDisabled)
+    {
+#ifdef DEBUG
+        AssertSz(FALSE, "WcaFinalizeWow64() called while Filesystem redirection was disabled.");
+#else
+        // If we aren't in debug mode, let's do our best to recover gracefully
+        WcaRevertWow64FSRedirection();
+#endif
+    }
+
+    s_fWow64Initialized = FALSE;
+    s_pfnDisableWow64 = NULL;
+    s_pfnRevertWow64 = NULL;
+
+    return S_OK;
+}