Frontend/WinHelper: Use UserSharedData for Windows build number.

Remove RtlGetVersion call. Make GetWindowsBuild function as a marco of KUSER_SHARED_DATA.NtBuildNumber.
Biswa96 · Oct 24, 2020 · e4b44dd · e4b44dd
1 parent 85c8a68
commit e4b44dd
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Showing 3 changed files with 4 additions and 25 deletions.
diff --git a/src/GetVmId.cpp b/src/GetVmId.cpp
@@ -64,7 +64,7 @@ HRESULT GetVmId(
 
     assert(hRes == 0);
 
-    DWORD BuildNumber = GetWindowsBuild();
+    const DWORD BuildNumber = GetWindowsBuild();
 
     /* Before Windows 10 Build 20211 RS */
     if (BuildNumber < 20211)

diff --git a/src/WinHelper.cpp b/src/WinHelper.cpp
@@ -38,9 +38,6 @@ typedef HRESULT (WINAPI *GETDISTROCONFIGPROC)(
     char **defaultEnvironmentVariables,
     int *defaultEnvironmentVariableCount);
 
-typedef void (WINAPI *RTLGETVERSIONPROC)(
-    OSVERSIONINFOW *lpVersionInformation);
-
 std::string GetErrorMessage(DWORD MessageId)
 {
     wchar_t *Buffer = NULL;
@@ -147,23 +144,3 @@ bool IsWslTwo(std::wstring DistroName)
     else
         return false;
 }
-
-DWORD GetWindowsBuild(void)
-{
-    HMODULE hMod = LoadLibraryExW(
-                   L"ntdll.dll",
-                   NULL,
-                   LOAD_LIBRARY_SEARCH_SYSTEM32);
-    assert(hMod != NULL);
-
-    RTLGETVERSIONPROC pfnRtlGetVersion = (RTLGETVERSIONPROC)
-                        GetProcAddress(hMod, "RtlGetVersion");
-    assert(pfnRtlGetVersion != NULL);
-
-    OSVERSIONINFOW info = {};
-    info.dwOSVersionInfoSize = sizeof info;
-    pfnRtlGetVersion(&info);
-    FreeLibrary(hMod);
-
-    return info.dwBuildNumber;
-}
diff --git a/src/WinHelper.hpp b/src/WinHelper.hpp
@@ -11,8 +11,10 @@
 #ifndef WINHELPER_HPP
 #define WINHELPER_HPP
 
+/* KUSER_SHARED_DATA.NtBuildNumber */
+#define GetWindowsBuild() (*(unsigned int *)(0x7FFE0000 + 0x0260))
+
 std::string GetErrorMessage(DWORD MessageId);
 bool IsWslTwo(std::wstring DistroName);
-DWORD GetWindowsBuild(void);
 
 #endif /* WINHELPER_HPP */