1 files changed, 188 insertions, 0 deletions

diff --git a/src/dutil/osutil.cpp b/src/dutil/osutil.cpp
new file mode 100644
index 00000000..d1a4dd9a
--- /dev/null
+++ b/src/dutil/osutil.cpp
@@ -0,0 +1,188 @@
+// 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"
+
+OS_VERSION vOsVersion = OS_VERSION_UNKNOWN;
+DWORD vdwOsServicePack = 0;
+
+/********************************************************************
+ OsGetVersion
+
+********************************************************************/
+extern "C" void DAPI OsGetVersion(
+    __out OS_VERSION* pVersion,
+    __out DWORD* pdwServicePack
+    )
+{
+    OSVERSIONINFOEXW ovi = { };
+
+    if (OS_VERSION_UNKNOWN == vOsVersion)
+    {
+        ovi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEXW);
+        ::GetVersionExW(reinterpret_cast<OSVERSIONINFOW*>(&ovi)); // only fails if version info size is set incorrectly.
+
+        vdwOsServicePack = static_cast<DWORD>(ovi.wServicePackMajor) << 16 | ovi.wServicePackMinor;
+        if (4 == ovi.dwMajorVersion)
+        {
+            vOsVersion = OS_VERSION_WINNT;
+        }
+        else if (5 == ovi.dwMajorVersion)
+        {
+            if (0 == ovi.dwMinorVersion)
+            {
+                vOsVersion = OS_VERSION_WIN2000;
+            }
+            else if (1 == ovi.dwMinorVersion)
+            {
+                vOsVersion = OS_VERSION_WINXP;
+            }
+            else if (2 == ovi.dwMinorVersion)
+            {
+                vOsVersion = OS_VERSION_WIN2003;
+            }
+            else
+            {
+                vOsVersion = OS_VERSION_FUTURE;
+            }
+        }
+        else if (6 == ovi.dwMajorVersion)
+        {
+            if (0 == ovi.dwMinorVersion)
+            {
+                vOsVersion = (VER_NT_WORKSTATION == ovi.wProductType) ? OS_VERSION_VISTA : OS_VERSION_WIN2008;
+            }
+            else if (1 == ovi.dwMinorVersion)
+            {
+                vOsVersion = (VER_NT_WORKSTATION == ovi.wProductType) ? OS_VERSION_WIN7 : OS_VERSION_WIN2008_R2;
+            }
+            else
+            {
+                vOsVersion = OS_VERSION_FUTURE;
+            }
+        }
+        else
+        {
+            vOsVersion = OS_VERSION_FUTURE;
+        }
+    }
+
+    *pVersion = vOsVersion;
+    *pdwServicePack = vdwOsServicePack;
+}
+
+extern "C" HRESULT DAPI OsCouldRunPrivileged(
+    __out BOOL* pfPrivileged
+    )
+{
+    HRESULT hr = S_OK;
+    BOOL fUacEnabled = FALSE;
+    SID_IDENTIFIER_AUTHORITY NtAuthority = SECURITY_NT_AUTHORITY;
+    PSID AdministratorsGroup = NULL;
+
+    // Do a best effort check to see if UAC is enabled on this machine.
+    OsIsUacEnabled(&fUacEnabled);
+
+    // If UAC is enabled then the process could run privileged by asking to elevate.
+    if (fUacEnabled)
+    {
+        *pfPrivileged = TRUE;
+    }
+    else // no UAC so only privilged if user is in administrators group.
+    {
+        *pfPrivileged = ::AllocateAndInitializeSid(&NtAuthority, 2, SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS, 0, 0, 0, 0, 0, 0, &AdministratorsGroup);
+        if (*pfPrivileged)
+        {
+            if (!::CheckTokenMembership(NULL, AdministratorsGroup, pfPrivileged))
+            {
+                 *pfPrivileged = FALSE;
+            }
+        }
+    }
+
+    ReleaseSid(AdministratorsGroup);
+    return hr;
+}
+
+extern "C" HRESULT DAPI OsIsRunningPrivileged(
+    __out BOOL* pfPrivileged
+    )
+{
+    HRESULT hr = S_OK;
+    UINT er = ERROR_SUCCESS;
+    HANDLE hToken = NULL;
+    TOKEN_ELEVATION_TYPE elevationType = TokenElevationTypeDefault;
+    DWORD dwSize = 0;
+    SID_IDENTIFIER_AUTHORITY NtAuthority = SECURITY_NT_AUTHORITY;
+    PSID AdministratorsGroup = NULL;
+
+    if (!::OpenProcessToken(::GetCurrentProcess(), TOKEN_QUERY, &hToken))
+    {
+        ExitOnLastError(hr, "Failed to open process token.");
+    }
+
+    if (::GetTokenInformation(hToken, TokenElevationType, &elevationType, sizeof(TOKEN_ELEVATION_TYPE), &dwSize))
+    {
+        *pfPrivileged = (TokenElevationTypeFull == elevationType);
+        ExitFunction1(hr = S_OK);
+    }
+
+    // If it's invalid argument, this means they don't support TokenElevationType, and we should fallback to another check
+    er = ::GetLastError();
+    if (ERROR_INVALID_FUNCTION == er)
+    {
+        er = ERROR_SUCCESS;
+    }
+    ExitOnWin32Error(er, hr, "Failed to get process token information.");
+
+    // Fallback to this check for some OS's (like XP)
+    *pfPrivileged = ::AllocateAndInitializeSid(&NtAuthority, 2, SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS, 0, 0, 0, 0, 0, 0, &AdministratorsGroup);
+    if (*pfPrivileged)
+    {
+        if (!::CheckTokenMembership(NULL, AdministratorsGroup, pfPrivileged))
+        {
+             *pfPrivileged = FALSE;
+        }
+    }
+
+LExit:
+    ReleaseSid(AdministratorsGroup);
+
+    if (hToken)
+    {
+        ::CloseHandle(hToken);
+    }
+
+    return hr;
+}
+
+extern "C" HRESULT DAPI OsIsUacEnabled(
+    __out BOOL* pfUacEnabled
+    )
+{
+    HRESULT hr = S_OK;
+    HKEY hk = NULL;
+    DWORD dwUacEnabled = 0;
+
+    *pfUacEnabled = FALSE; // assume UAC not enabled.
+
+    hr = RegOpen(HKEY_LOCAL_MACHINE, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System", KEY_READ, &hk);
+    if (E_FILENOTFOUND == hr)
+    {
+        ExitFunction1(hr = S_OK);
+    }
+    ExitOnFailure(hr, "Failed to open system policy key to detect UAC.");
+
+    hr = RegReadNumber(hk, L"EnableLUA", &dwUacEnabled);
+    if (E_FILENOTFOUND == hr)
+    {
+        ExitFunction1(hr = S_OK);
+    }
+    ExitOnFailure(hr, "Failed to read registry value to detect UAC.");
+
+    *pfUacEnabled = (0 != dwUacEnabled);
+
+LExit:
+    ReleaseRegKey(hk);
+
+    return hr;
+}