[PATCH 1/1] ntdll: Introduce "WINEWOW64" environment variable, to enable new WoW64 behavior.

[Huw D. M. Davies]

From: "Huw D. M. Davies"

https://www.winehq.org/pipermail/wine-devel/2022-April/213620.html

Co-authored-by: Davide Beatrici 
---
 dlls/ntdll/loader.c   | 11 ++++++++++-
 dlls/ntdll/unix/env.c | 12 +++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/dlls/ntdll/loader.c b/dlls/ntdll/loader.c
index 043bce67ea9..1b706c14b04 100644
--- a/dlls/ntdll/loader.c
+++ b/dlls/ntdll/loader.c
@@ -1572,7 +1572,16 @@ static NTSTATUS MODULE_InitDLL( WINE_MODREF *wm, UINT reason, LPVOID lpReserved
     if (wm->ldr.Flags & LDR_DONT_RESOLVE_REFS) return STATUS_SUCCESS;
     if (wm->ldr.TlsIndex != -1) call_tls_callbacks( wm->ldr.DllBase, reason );
     if (wm->ldr.Flags & LDR_WINE_INTERNAL && reason == DLL_PROCESS_ATTACH)
-        unix_funcs->init_builtin_dll( wm->ldr.DllBase );
+    {
+        UNICODE_STRING name, value = { 0 };
+
+        RtlInitUnicodeString( &name, L"WINEWOW64" );
+        if (RtlQueryEnvironmentVariable_U( NULL, &name, &value ) != STATUS_VARIABLE_NOT_FOUND)
+            TRACE("WINEWOW64 env var found, not calling init_builtin_dll()\n");
+        else
+            unix_funcs->init_builtin_dll( wm->ldr.DllBase );
+    }
+
     if (!entry) return STATUS_SUCCESS;

if (TRACE_ON(relay))
diff --git a/dlls/ntdll/unix/env.c b/dlls/ntdll/unix/env.c
index 105038a34cb..dc9a2adf9a3 100644
--- a/dlls/ntdll/unix/env.c
+++ b/dlls/ntdll/unix/env.c
@@ -1929,7 +1929,17 @@ static RTL_USER_PROCESS_PARAMETERS *build_initial_params( void **module )
     if (!status)
     {
         if (main_image_info.ImageCharacteristics & IMAGE_FILE_DLL) status = STATUS_INVALID_IMAGE_FORMAT;
-        if (main_image_info.Machine != current_machine) status = STATUS_INVALID_IMAGE_FORMAT;
+        if (main_image_info.Machine != current_machine)
+        {
+            static const WCHAR wow64W[] = {'W','I','N','E','W','O','W','6','4'};
+
+            if (find_env_var( env, env_pos, wow64W, ARRAY_SIZE(wow64W) ))
+                TRACE("WINEWOW64 env var found, ignoring arch mismatch (current: %04x, image: %04x)\n",
+                      current_machine,
+                      main_image_info.Machine);
+            else
+                status = STATUS_INVALID_IMAGE_FORMAT;
+        }
     }

if (status)  /* try launching it through start.exe */