1 files changed, 926 insertions, 0 deletions

diff --git a/src/dutil/regutil.cpp b/src/dutil/regutil.cpp
new file mode 100644
index 00000000..ec370f58
--- /dev/null
+++ b/src/dutil/regutil.cpp
@@ -0,0 +1,926 @@
+// 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 PFN_REGCREATEKEYEXW vpfnRegCreateKeyExW = ::RegCreateKeyExW;
+static PFN_REGOPENKEYEXW vpfnRegOpenKeyExW = ::RegOpenKeyExW;
+static PFN_REGDELETEKEYEXW vpfnRegDeleteKeyExW = NULL;
+static PFN_REGDELETEKEYEXW vpfnRegDeleteKeyExWFromLibrary = NULL;
+static PFN_REGDELETEKEYW vpfnRegDeleteKeyW = ::RegDeleteKeyW;
+static PFN_REGENUMKEYEXW vpfnRegEnumKeyExW = ::RegEnumKeyExW;
+static PFN_REGENUMVALUEW vpfnRegEnumValueW = ::RegEnumValueW;
+static PFN_REGQUERYINFOKEYW vpfnRegQueryInfoKeyW = ::RegQueryInfoKeyW;
+static PFN_REGQUERYVALUEEXW vpfnRegQueryValueExW = ::RegQueryValueExW;
+static PFN_REGSETVALUEEXW vpfnRegSetValueExW = ::RegSetValueExW;
+static PFN_REGDELETEVALUEW vpfnRegDeleteValueW = ::RegDeleteValueW;
+
+static HMODULE vhAdvApi32Dll = NULL;
+static BOOL vfRegInitialized = FALSE;
+
+/********************************************************************
+ RegInitialize - initializes regutil
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegInitialize(
+    )
+{
+    HRESULT hr = S_OK;
+
+    hr = LoadSystemLibrary(L"AdvApi32.dll", &vhAdvApi32Dll);
+    ExitOnFailure(hr, "Failed to load AdvApi32.dll");
+
+    // ignore failures - if this doesn't exist, we'll fall back to RegDeleteKeyW
+    vpfnRegDeleteKeyExWFromLibrary = reinterpret_cast<PFN_REGDELETEKEYEXW>(::GetProcAddress(vhAdvApi32Dll, "RegDeleteKeyExW"));
+
+    if (NULL == vpfnRegDeleteKeyExW)
+    {
+        vpfnRegDeleteKeyExW = vpfnRegDeleteKeyExWFromLibrary;
+    }
+
+    vfRegInitialized = TRUE;
+
+LExit:
+    return hr;
+}
+
+
+/********************************************************************
+ RegUninitialize - uninitializes regutil
+
+*********************************************************************/
+extern "C" void DAPI RegUninitialize(
+    )
+{
+    if (vhAdvApi32Dll)
+    {
+        ::FreeLibrary(vhAdvApi32Dll);
+        vhAdvApi32Dll = NULL;
+        vpfnRegDeleteKeyExWFromLibrary = NULL;
+        vpfnRegDeleteKeyExW = NULL;
+    }
+
+    vfRegInitialized = FALSE;
+}
+
+
+/********************************************************************
+ RegFunctionOverride - overrides the registry functions. Typically used
+                       for unit testing.
+
+*********************************************************************/
+extern "C" void DAPI RegFunctionOverride(
+    __in_opt PFN_REGCREATEKEYEXW pfnRegCreateKeyExW,
+    __in_opt PFN_REGOPENKEYEXW pfnRegOpenKeyExW,
+    __in_opt PFN_REGDELETEKEYEXW pfnRegDeleteKeyExW,
+    __in_opt PFN_REGENUMKEYEXW pfnRegEnumKeyExW,
+    __in_opt PFN_REGENUMVALUEW pfnRegEnumValueW,
+    __in_opt PFN_REGQUERYINFOKEYW pfnRegQueryInfoKeyW,
+    __in_opt PFN_REGQUERYVALUEEXW pfnRegQueryValueExW,
+    __in_opt PFN_REGSETVALUEEXW pfnRegSetValueExW,
+    __in_opt PFN_REGDELETEVALUEW pfnRegDeleteValueW
+    )
+{
+    vpfnRegCreateKeyExW = pfnRegCreateKeyExW ? pfnRegCreateKeyExW : ::RegCreateKeyExW;
+    vpfnRegOpenKeyExW = pfnRegOpenKeyExW ? pfnRegOpenKeyExW : ::RegOpenKeyExW;
+    vpfnRegDeleteKeyExW = pfnRegDeleteKeyExW ? pfnRegDeleteKeyExW : vpfnRegDeleteKeyExWFromLibrary;
+    vpfnRegEnumKeyExW = pfnRegEnumKeyExW ? pfnRegEnumKeyExW : ::RegEnumKeyExW;
+    vpfnRegEnumValueW = pfnRegEnumValueW ? pfnRegEnumValueW : ::RegEnumValueW;
+    vpfnRegQueryInfoKeyW = pfnRegQueryInfoKeyW ? pfnRegQueryInfoKeyW : ::RegQueryInfoKeyW;
+    vpfnRegQueryValueExW = pfnRegQueryValueExW ? pfnRegQueryValueExW : ::RegQueryValueExW;
+    vpfnRegSetValueExW = pfnRegSetValueExW ? pfnRegSetValueExW : ::RegSetValueExW;
+    vpfnRegDeleteValueW = pfnRegDeleteValueW ? pfnRegDeleteValueW : ::RegDeleteValueW;
+}
+
+
+/********************************************************************
+ RegCreate - creates a registry key.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegCreate(
+    __in HKEY hkRoot,
+    __in_z LPCWSTR wzSubKey,
+    __in DWORD dwAccess,
+    __out HKEY* phk
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+
+    er = vpfnRegCreateKeyExW(hkRoot, wzSubKey, 0, NULL, REG_OPTION_NON_VOLATILE, dwAccess, NULL, phk, NULL);
+    ExitOnWin32Error(er, hr, "Failed to create registry key.");
+
+LExit:
+    return hr;
+}
+
+
+/********************************************************************
+ RegCreate - creates a registry key with extra options.
+
+*********************************************************************/
+HRESULT DAPI RegCreateEx(
+    __in HKEY hkRoot,
+    __in_z LPCWSTR wzSubKey,
+    __in DWORD dwAccess,
+    __in BOOL fVolatile,
+    __in_opt SECURITY_ATTRIBUTES* pSecurityAttributes,
+    __out HKEY* phk,
+    __out_opt BOOL* pfCreated
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    DWORD dwDisposition;
+
+    er = vpfnRegCreateKeyExW(hkRoot, wzSubKey, 0, NULL, fVolatile ? REG_OPTION_VOLATILE : REG_OPTION_NON_VOLATILE, dwAccess, pSecurityAttributes, phk, &dwDisposition);
+    ExitOnWin32Error(er, hr, "Failed to create registry key.");
+
+    if (pfCreated)
+    {
+        *pfCreated = (REG_CREATED_NEW_KEY == dwDisposition);
+    }
+
+LExit:
+    return hr;
+}
+
+
+/********************************************************************
+ RegOpen - opens a registry key.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegOpen(
+    __in HKEY hkRoot,
+    __in_z LPCWSTR wzSubKey,
+    __in DWORD dwAccess,
+    __out HKEY* phk
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+
+    er = vpfnRegOpenKeyExW(hkRoot, wzSubKey, 0, dwAccess, phk);
+    if (E_FILENOTFOUND == HRESULT_FROM_WIN32(er))
+    {
+        ExitFunction1(hr = E_FILENOTFOUND);
+    }
+    ExitOnWin32Error(er, hr, "Failed to open registry key.");
+
+LExit:
+    return hr;
+}
+
+
+/********************************************************************
+ RegDelete - deletes a registry key (and optionally it's whole tree).
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegDelete(
+    __in HKEY hkRoot,
+    __in_z LPCWSTR wzSubKey,
+    __in REG_KEY_BITNESS kbKeyBitness,
+    __in BOOL fDeleteTree
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    LPWSTR pszEnumeratedSubKey = NULL;
+    LPWSTR pszRecursiveSubKey = NULL;
+    HKEY hkKey = NULL;
+    REGSAM samDesired = 0;
+
+    if (!vfRegInitialized && REG_KEY_DEFAULT != kbKeyBitness)
+    {
+        hr = E_INVALIDARG;
+        ExitOnFailure(hr, "RegInitialize must be called first in order to RegDelete() a key with non-default bit attributes!");
+    }
+
+    switch (kbKeyBitness)
+    {
+    case REG_KEY_32BIT:
+        samDesired = KEY_WOW64_32KEY;
+        break;
+    case REG_KEY_64BIT:
+        samDesired = KEY_WOW64_64KEY;
+        break;
+    case REG_KEY_DEFAULT:
+        // Nothing to do
+        break;
+    }
+
+    if (fDeleteTree)
+    {
+        hr = RegOpen(hkRoot, wzSubKey, KEY_READ | samDesired, &hkKey);
+        if (E_FILENOTFOUND == hr)
+        {
+            ExitFunction1(hr = S_OK);
+        }
+        ExitOnFailure(hr, "Failed to open this key for enumerating subkeys", wzSubKey);
+
+        // Yes, keep enumerating the 0th item, because we're deleting it every time
+        while (E_NOMOREITEMS != (hr = RegKeyEnum(hkKey, 0, &pszEnumeratedSubKey)))
+        {
+            ExitOnFailure(hr, "Failed to enumerate key 0");
+            
+            hr = PathConcat(wzSubKey, pszEnumeratedSubKey, &pszRecursiveSubKey);
+            ExitOnFailure(hr, "Failed to concatenate paths while recursively deleting subkeys. Path1: %ls, Path2: %ls", wzSubKey, pszEnumeratedSubKey);
+
+            hr = RegDelete(hkRoot, pszRecursiveSubKey, kbKeyBitness, fDeleteTree);
+            ExitOnFailure(hr, "Failed to recursively delete subkey: %ls", pszRecursiveSubKey);
+        }
+
+        hr = S_OK;
+    }
+
+    if (NULL != vpfnRegDeleteKeyExW)
+    {
+        er = vpfnRegDeleteKeyExW(hkRoot, wzSubKey, samDesired, 0);
+        if (E_FILENOTFOUND == HRESULT_FROM_WIN32(er))
+        {
+            ExitFunction1(hr = E_FILENOTFOUND);
+        }
+        ExitOnWin32Error(er, hr, "Failed to delete registry key (ex).");
+    }
+    else
+    {
+        er = vpfnRegDeleteKeyW(hkRoot, wzSubKey);
+        if (E_FILENOTFOUND == HRESULT_FROM_WIN32(er))
+        {
+            ExitFunction1(hr = E_FILENOTFOUND);
+        }
+        ExitOnWin32Error(er, hr, "Failed to delete registry key.");
+    }
+
+LExit:
+    ReleaseRegKey(hkKey);
+    ReleaseStr(pszEnumeratedSubKey);
+    ReleaseStr(pszRecursiveSubKey);
+
+    return hr;
+}
+
+
+/********************************************************************
+ RegKeyEnum - enumerates a registry key.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegKeyEnum(
+    __in HKEY hk,
+    __in DWORD dwIndex,
+    __deref_out_z LPWSTR* psczKey
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    DWORD cch = 0;
+
+    if (psczKey && *psczKey)
+    {
+        hr = StrMaxLength(*psczKey, reinterpret_cast<DWORD_PTR*>(&cch));
+        ExitOnFailure(hr, "Failed to determine length of string.");
+    }
+
+    if (2 > cch)
+    {
+        cch = 2;
+
+        hr = StrAlloc(psczKey, cch);
+        ExitOnFailure(hr, "Failed to allocate string to minimum size.");
+    }
+
+    er = vpfnRegEnumKeyExW(hk, dwIndex, *psczKey, &cch, NULL, NULL, NULL, NULL);
+    if (ERROR_MORE_DATA == er)
+    {
+        er = vpfnRegQueryInfoKeyW(hk, NULL, NULL, NULL, NULL, &cch, NULL, NULL, NULL, NULL, NULL, NULL);
+        ExitOnWin32Error(er, hr, "Failed to get max size of subkey name under registry key.");
+
+        ++cch; // add one because RegQueryInfoKeyW() returns the length of the subkeys without the null terminator.
+        hr = StrAlloc(psczKey, cch);
+        ExitOnFailure(hr, "Failed to allocate string bigger for enum registry key.");
+
+        er = vpfnRegEnumKeyExW(hk, dwIndex, *psczKey, &cch, NULL, NULL, NULL, NULL);
+    }
+    else if (ERROR_NO_MORE_ITEMS == er)
+    {
+        ExitFunction1(hr = E_NOMOREITEMS);
+    }
+    ExitOnWin32Error(er, hr, "Failed to enum registry key.");
+
+    // Always ensure the registry key name is null terminated.
+#pragma prefast(push)
+#pragma prefast(disable:26018)
+    (*psczKey)[cch] = L'\0'; // note that cch will always be one less than the size of the buffer because that's how RegEnumKeyExW() works.
+#pragma prefast(pop)
+
+LExit:
+    return hr;
+}
+
+
+/********************************************************************
+ RegValueEnum - enumerates a registry value.
+
+*********************************************************************/
+HRESULT DAPI RegValueEnum(
+    __in HKEY hk,
+    __in DWORD dwIndex,
+    __deref_out_z LPWSTR* psczName,
+    __out_opt DWORD *pdwType
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    DWORD cbValueName = 0;
+
+    er = vpfnRegQueryInfoKeyW(hk, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &cbValueName, NULL, NULL, NULL);
+    ExitOnWin32Error(er, hr, "Failed to get max size of value name under registry key.");
+
+    // Add one for null terminator
+    ++cbValueName;
+
+    hr = StrAlloc(psczName, cbValueName);
+    ExitOnFailure(hr, "Failed to allocate array for registry value name");
+
+    er = vpfnRegEnumValueW(hk, dwIndex, *psczName, &cbValueName, NULL, pdwType, NULL, NULL);
+    if (ERROR_NO_MORE_ITEMS == er)
+    {
+        ExitFunction1(hr = E_NOMOREITEMS);
+    }
+    ExitOnWin32Error(er, hr, "Failed to enumerate registry value");
+
+LExit:
+    return hr;
+}
+
+/********************************************************************
+ RegGetType - reads a registry key value type.
+ *********************************************************************/
+HRESULT DAPI RegGetType(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __out DWORD *pdwType
+     )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+
+    er = vpfnRegQueryValueExW(hk, wzName, NULL, pdwType, NULL, NULL);
+    if (E_FILENOTFOUND == HRESULT_FROM_WIN32(er))
+    {
+        ExitFunction1(hr = E_FILENOTFOUND);
+    }
+    ExitOnWin32Error(er, hr, "Failed to read registry value.");
+LExit:
+
+    return hr;
+}
+
+/********************************************************************
+ RegReadBinary - reads a registry key binary value.
+ NOTE: caller is responsible for freeing *ppbBuffer
+*********************************************************************/
+HRESULT DAPI RegReadBinary(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __deref_out_bcount_opt(*pcbBuffer) BYTE** ppbBuffer,
+    __out SIZE_T *pcbBuffer
+     )
+{
+    HRESULT hr = S_OK;
+    LPBYTE pbBuffer = NULL;
+    DWORD er = ERROR_SUCCESS;
+    DWORD cb = 0;
+    DWORD dwType = 0;
+
+    er = vpfnRegQueryValueExW(hk, wzName, NULL, &dwType, NULL, &cb);
+    ExitOnWin32Error(er, hr, "Failed to get size of registry value.");
+
+    // Zero-length binary values can exist
+    if (0 < cb)
+    {
+        pbBuffer = static_cast<LPBYTE>(MemAlloc(cb, FALSE));
+        ExitOnNull(pbBuffer, hr, E_OUTOFMEMORY, "Failed to allocate buffer for binary registry value.");
+
+        er = vpfnRegQueryValueExW(hk, wzName, NULL, &dwType, pbBuffer, &cb);
+        if (E_FILENOTFOUND == HRESULT_FROM_WIN32(er))
+        {
+            ExitFunction1(hr = E_FILENOTFOUND);
+        }
+        ExitOnWin32Error(er, hr, "Failed to read registry value.");
+    }
+
+    if (REG_BINARY == dwType)
+    {
+        *ppbBuffer = pbBuffer;
+        pbBuffer = NULL;
+        *pcbBuffer = cb;
+    }
+    else
+    {
+        hr = HRESULT_FROM_WIN32(ERROR_INVALID_DATATYPE);
+        ExitOnRootFailure(hr, "Error reading binary registry value due to unexpected data type: %u", dwType);
+    }
+
+LExit:
+    ReleaseMem(pbBuffer);
+
+    return hr;
+}
+
+
+/********************************************************************
+ RegReadString - reads a registry key value as a string.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegReadString(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __deref_out_z LPWSTR* psczValue
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    DWORD cch = 0;
+    DWORD cb = 0;
+    DWORD dwType = 0;
+    LPWSTR sczExpand = NULL;
+
+    if (psczValue && *psczValue)
+    {
+        hr = StrMaxLength(*psczValue, reinterpret_cast<DWORD_PTR*>(&cch));
+        ExitOnFailure(hr, "Failed to determine length of string.");
+    }
+
+    if (2 > cch)
+    {
+        cch = 2;
+
+        hr = StrAlloc(psczValue, cch);
+        ExitOnFailure(hr, "Failed to allocate string to minimum size.");
+    }
+
+    cb = sizeof(WCHAR) * (cch - 1); // subtract one to ensure there will be a space at the end of the string for the null terminator.
+    er = vpfnRegQueryValueExW(hk, wzName, NULL, &dwType, reinterpret_cast<LPBYTE>(*psczValue), &cb);
+    if (ERROR_MORE_DATA == er)
+    {
+        cch = cb / sizeof(WCHAR) + 1; // add one to ensure there will be space at the end for the null terminator
+        hr = StrAlloc(psczValue, cch);
+        ExitOnFailure(hr, "Failed to allocate string bigger for registry value.");
+
+        er = vpfnRegQueryValueExW(hk, wzName, NULL, &dwType, reinterpret_cast<LPBYTE>(*psczValue), &cb);
+    }
+    if (E_FILENOTFOUND == HRESULT_FROM_WIN32(er))
+    {
+        ExitFunction1(hr = E_FILENOTFOUND);
+    }
+    ExitOnWin32Error(er, hr, "Failed to read registry key.");
+
+    if (REG_SZ == dwType || REG_EXPAND_SZ == dwType)
+    {
+        // Always ensure the registry value is null terminated.
+        (*psczValue)[cch - 1] = L'\0';
+
+        if (REG_EXPAND_SZ == dwType)
+        {
+            hr = StrAllocString(&sczExpand, *psczValue, 0);
+            ExitOnFailure(hr, "Failed to copy registry value to expand.");
+
+            hr = PathExpand(psczValue, sczExpand, PATH_EXPAND_ENVIRONMENT);
+            ExitOnFailure(hr, "Failed to expand registry value: %ls", *psczValue);
+        }
+    }
+    else
+    {
+        hr = HRESULT_FROM_WIN32(ERROR_INVALID_DATATYPE);
+        ExitOnRootFailure(hr, "Error reading string registry value due to unexpected data type: %u", dwType);
+    }
+
+LExit:
+    ReleaseStr(sczExpand);
+
+    return hr;
+}
+
+
+/********************************************************************
+ RegReadStringArray - reads a registry key value REG_MULTI_SZ value as a string array.
+
+*********************************************************************/
+HRESULT DAPI RegReadStringArray(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __deref_out_ecount_opt(pcStrings) LPWSTR** prgsczStrings,
+    __out DWORD *pcStrings
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    DWORD dwNullCharacters = 0;
+    DWORD dwType = 0;
+    DWORD cb = 0;
+    DWORD cch = 0;
+    LPCWSTR wzSource = NULL;
+    LPWSTR sczValue = NULL;
+
+    er = vpfnRegQueryValueExW(hk, wzName, NULL, &dwType, reinterpret_cast<LPBYTE>(sczValue), &cb);
+    if (0 < cb)
+    {
+        cch = cb / sizeof(WCHAR);
+        hr = StrAlloc(&sczValue, cch);
+        ExitOnFailure(hr, "Failed to allocate string for registry value.");
+
+        er = vpfnRegQueryValueExW(hk, wzName, NULL, &dwType, reinterpret_cast<LPBYTE>(sczValue), &cb);
+    }
+    if (E_FILENOTFOUND == HRESULT_FROM_WIN32(er))
+    {
+        ExitFunction1(hr = E_FILENOTFOUND);
+    }
+    ExitOnWin32Error(er, hr, "Failed to read registry key.");
+
+    if (cb / sizeof(WCHAR) != cch)
+    {
+        hr = E_UNEXPECTED;
+        ExitOnFailure(hr, "The size of registry value %ls unexpected changed between 2 reads", wzName);
+    }
+
+    if (REG_MULTI_SZ != dwType)
+    {
+        hr = HRESULT_FROM_WIN32(ERROR_INVALID_DATATYPE);
+        ExitOnRootFailure(hr, "Tried to read string array, but registry value %ls is of an incorrect type", wzName);
+    }
+
+    // Value exists, but is empty, so no strings to return.
+    if (2 > cch)
+    {
+        *prgsczStrings = NULL;
+        *pcStrings = 0;
+        ExitFunction1(hr = S_OK);
+    }
+
+    // The docs specifically say if the value was written without double-null-termination, it'll get read back without it too.
+    if (L'\0' != sczValue[cch-1] || L'\0' != sczValue[cch-2])
+    {
+        hr = E_INVALIDARG;
+        ExitOnFailure(hr, "Tried to read string array, but registry value %ls is invalid (isn't double-null-terminated)", wzName);
+    }
+
+    cch = cb / sizeof(WCHAR);
+    for (DWORD i = 0; i < cch; ++i)
+    {
+        if (L'\0' == sczValue[i])
+        {
+            ++dwNullCharacters;
+        }
+    }
+
+    // There's one string for every null character encountered (except the extra 1 at the end of the string)
+    *pcStrings = dwNullCharacters - 1;
+    hr = MemEnsureArraySize(reinterpret_cast<LPVOID *>(prgsczStrings), *pcStrings, sizeof(LPWSTR), 0);
+    ExitOnFailure(hr, "Failed to resize array while reading REG_MULTI_SZ value");
+
+#pragma prefast(push)
+#pragma prefast(disable:26010)
+    wzSource = sczValue;
+    for (DWORD i = 0; i < *pcStrings; ++i)
+    {
+        hr = StrAllocString(&(*prgsczStrings)[i], wzSource, 0);
+        ExitOnFailure(hr, "Failed to allocate copy of string");
+
+        // Skip past this string
+        wzSource += lstrlenW(wzSource) + 1;
+    }
+#pragma prefast(pop)
+
+LExit:
+    ReleaseStr(sczValue);
+
+    return hr;
+}
+
+
+/********************************************************************
+ RegReadVersion - reads a registry key value as a version.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegReadVersion(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __out DWORD64* pdw64Version
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    DWORD dwType = 0;
+    DWORD cb = 0;
+    LPWSTR sczVersion = NULL;
+
+    cb = sizeof(DWORD64);
+    er = vpfnRegQueryValueExW(hk, wzName, NULL, &dwType, reinterpret_cast<LPBYTE>(*pdw64Version), &cb);
+    if (E_FILENOTFOUND == HRESULT_FROM_WIN32(er))
+    {
+        ExitFunction1(hr = E_FILENOTFOUND);
+    }
+    if (REG_SZ == dwType || REG_EXPAND_SZ == dwType)
+    {
+        hr = RegReadString(hk, wzName, &sczVersion);
+        ExitOnFailure(hr, "Failed to read registry version as string.");
+
+        hr = FileVersionFromStringEx(sczVersion, 0, pdw64Version);
+        ExitOnFailure(hr, "Failed to convert registry string to version.");
+    }
+    else if (REG_QWORD == dwType)
+    {
+        ExitOnWin32Error(er, hr, "Failed to read registry key.");
+    }
+    else // unexpected data type
+    {
+        hr = HRESULT_FROM_WIN32(ERROR_INVALID_DATATYPE);
+        ExitOnRootFailure(hr, "Error reading version registry value due to unexpected data type: %u", dwType);
+    }
+
+LExit:
+    ReleaseStr(sczVersion);
+
+    return hr;
+}
+
+
+/********************************************************************
+ RegReadNumber - reads a DWORD registry key value as a number.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegReadNumber(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __out DWORD* pdwValue
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    DWORD dwType = 0;
+    DWORD cb = sizeof(DWORD);
+
+    er = vpfnRegQueryValueExW(hk, wzName, NULL, &dwType, reinterpret_cast<LPBYTE>(pdwValue), &cb);
+    if (E_FILENOTFOUND == HRESULT_FROM_WIN32(er))
+    {
+        ExitFunction1(hr = E_FILENOTFOUND);
+    }
+    ExitOnWin32Error(er, hr, "Failed to query registry key value.");
+
+    if (REG_DWORD != dwType)
+    {
+        hr = HRESULT_FROM_WIN32(ERROR_INVALID_DATATYPE);
+        ExitOnRootFailure(hr, "Error reading version registry value due to unexpected data type: %u", dwType);
+    }
+
+LExit:
+    return hr;
+}
+
+
+/********************************************************************
+ RegReadQword - reads a QWORD registry key value as a number.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegReadQword(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __out DWORD64* pqwValue
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    DWORD dwType = 0;
+    DWORD cb = sizeof(DWORD64);
+
+    er = vpfnRegQueryValueExW(hk, wzName, NULL, &dwType, reinterpret_cast<LPBYTE>(pqwValue), &cb);
+    if (E_FILENOTFOUND == HRESULT_FROM_WIN32(er))
+    {
+        ExitFunction1(hr = E_FILENOTFOUND);
+    }
+    ExitOnWin32Error(er, hr, "Failed to query registry key value.");
+
+    if (REG_QWORD != dwType)
+    {
+        hr = HRESULT_FROM_WIN32(ERROR_INVALID_DATATYPE);
+        ExitOnRootFailure(hr, "Error reading version registry value due to unexpected data type: %u", dwType);
+    }
+
+LExit:
+    return hr;
+}
+
+
+/********************************************************************
+ RegWriteBinary - writes a registry key value as a binary.
+
+*********************************************************************/
+HRESULT DAPI RegWriteBinary(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __in_bcount(cbBuffer) const BYTE *pbBuffer,
+    __in DWORD cbBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+
+    er = vpfnRegSetValueExW(hk, wzName, 0, REG_BINARY, pbBuffer, cbBuffer);
+    ExitOnWin32Error(er, hr, "Failed to write binary registry value with name: %ls", wzName);
+
+LExit:
+    return hr;
+}
+
+
+/********************************************************************
+ RegWriteString - writes a registry key value as a string.
+
+ Note: if wzValue is NULL the value will be removed.
+*********************************************************************/
+extern "C" HRESULT DAPI RegWriteString(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __in_z_opt LPCWSTR wzValue
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    DWORD cbValue = 0;
+
+    if (wzValue)
+    {
+        hr = ::StringCbLengthW(wzValue, DWORD_MAX, reinterpret_cast<size_t*>(&cbValue));
+        ExitOnFailure(hr, "Failed to determine length of registry value: %ls", wzName);
+
+        er = vpfnRegSetValueExW(hk, wzName, 0, REG_SZ, reinterpret_cast<const BYTE *>(wzValue), cbValue);
+        ExitOnWin32Error(er, hr, "Failed to set registry value: %ls", wzName);
+    }
+    else
+    {
+        er = vpfnRegDeleteValueW(hk, wzName);
+        if (ERROR_FILE_NOT_FOUND == er || ERROR_PATH_NOT_FOUND == er)
+        {
+            er = ERROR_SUCCESS;
+        }
+        ExitOnWin32Error(er, hr, "Failed to delete registry value: %ls", wzName);
+    }
+
+LExit:
+    return hr;
+}
+
+
+/********************************************************************
+ RegWriteStringFormatted - writes a registry key value as a formatted string.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegWriteStringFormatted(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __in __format_string LPCWSTR szFormat,
+    ...
+    )
+{
+    HRESULT hr = S_OK;
+    LPWSTR sczValue = NULL;
+    va_list args;
+
+    va_start(args, szFormat);
+    hr = StrAllocFormattedArgs(&sczValue, szFormat, args);
+    va_end(args);
+    ExitOnFailure(hr, "Failed to allocate %ls value.", wzName);
+
+    hr = RegWriteString(hk, wzName, sczValue);
+
+LExit:
+    ReleaseStr(sczValue);
+
+    return hr;
+}
+
+
+/********************************************************************
+ RegWriteStringArray - writes an array of strings as a REG_MULTI_SZ value
+
+*********************************************************************/
+HRESULT DAPI RegWriteStringArray(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __in_ecount(cValues) LPWSTR *rgwzValues,
+    __in DWORD cValues
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+    LPWSTR wzCopyDestination = NULL;
+    LPCWSTR wzWriteValue = NULL;
+    LPWSTR sczWriteValue = NULL;
+    DWORD dwTotalStringSize = 0;
+    DWORD cbTotalStringSize = 0;
+    DWORD dwTemp = 0;
+
+    if (0 == cValues)
+    {
+        wzWriteValue = L"\0";
+    }
+    else
+    {
+        // Add space for the null terminator
+        dwTotalStringSize = 1;
+
+        for (DWORD i = 0; i < cValues; ++i)
+        {
+            dwTemp = dwTotalStringSize;
+            hr = ::DWordAdd(dwTemp, 1 + lstrlenW(rgwzValues[i]), &dwTotalStringSize);
+            ExitOnFailure(hr, "DWORD Overflow while adding length of string to write REG_MULTI_SZ");
+        }
+
+        hr = StrAlloc(&sczWriteValue, dwTotalStringSize);
+        ExitOnFailure(hr, "Failed to allocate space for string while writing REG_MULTI_SZ");
+
+        wzCopyDestination = sczWriteValue;
+        dwTemp = dwTotalStringSize;
+        for (DWORD i = 0; i < cValues; ++i)
+        {
+            hr = ::StringCchCopyW(wzCopyDestination, dwTotalStringSize, rgwzValues[i]);
+            ExitOnFailure(hr, "failed to copy string: %ls", rgwzValues[i]);
+            
+            dwTemp -= lstrlenW(rgwzValues[i]) + 1;
+            wzCopyDestination += lstrlenW(rgwzValues[i]) + 1;
+        }
+
+        wzWriteValue = sczWriteValue;
+    }
+
+    hr = ::DWordMult(dwTotalStringSize, sizeof(WCHAR), &cbTotalStringSize);
+    ExitOnFailure(hr, "Failed to get total string size in bytes");
+
+    er = vpfnRegSetValueExW(hk, wzName, 0, REG_MULTI_SZ, reinterpret_cast<const BYTE *>(wzWriteValue), cbTotalStringSize);
+    ExitOnWin32Error(er, hr, "Failed to set registry value to array of strings (first string of which is): %ls", wzWriteValue);
+
+LExit:
+    ReleaseStr(sczWriteValue);
+
+    return hr;
+}
+
+/********************************************************************
+ RegWriteNumber - writes a registry key value as a number.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegWriteNumber(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __in DWORD dwValue
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+
+    er = vpfnRegSetValueExW(hk, wzName, 0, REG_DWORD, reinterpret_cast<const BYTE *>(&dwValue), sizeof(dwValue));
+    ExitOnWin32Error(er, hr, "Failed to set %ls value.", wzName);
+
+LExit:
+    return hr;
+}
+
+/********************************************************************
+ RegWriteQword - writes a registry key value as a Qword.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegWriteQword(
+    __in HKEY hk,
+    __in_z_opt LPCWSTR wzName,
+    __in DWORD64 qwValue
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+
+    er = vpfnRegSetValueExW(hk, wzName, 0, REG_QWORD, reinterpret_cast<const BYTE *>(&qwValue), sizeof(qwValue));
+    ExitOnWin32Error(er, hr, "Failed to set %ls value.", wzName);
+
+LExit:
+    return hr;
+}
+
+/********************************************************************
+ RegQueryKey - queries the key for the number of subkeys and values.
+
+*********************************************************************/
+extern "C" HRESULT DAPI RegQueryKey(
+    __in HKEY hk,
+    __out_opt DWORD* pcSubKeys,
+    __out_opt DWORD* pcValues
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD er = ERROR_SUCCESS;
+
+    er = vpfnRegQueryInfoKeyW(hk, NULL, NULL, NULL, pcSubKeys, NULL, NULL, pcValues, NULL, NULL, NULL, NULL);
+    ExitOnWin32Error(er, hr, "Failed to get the number of subkeys and values under registry key.");
+
+LExit:
+    return hr;
+}