From: IgniteX contributors
Subject: [PATCH] ntdll: route selected executables to trusted graphics modules

This patch does not contain or redistribute Apple GPTK/D3DMetal binaries.
It only lets a caller opt selected Windows executables into a DLL directory
owned by the user while the rest of the Wine session keeps the base renderer.

Set both variables to activate the user-supplied D3DMetal route:

  IGNITEX_D3DMETAL_DLL_PATH=/absolute/path/to/user/GPTK/lib/wine
  IGNITEX_D3DMETAL_EXES=RDR2.exe

Set both variables to activate the receipt-verified DXMT route:

  IGNITEX_DXMT_DLL_PATH=/absolute/path/to/dxmt/v0.80
  IGNITEX_DXMT_EXES=PenguinHotel-Win64-Shipping.exe

The routes are mutually exclusive and match exact executable basenames. DXMT
only takes ownership of D3D10Core, D3D11 and DXGI; it never intercepts D3D12.

The Vulkan guard keeps a deliberately non-Vulkan build valid when the
downstream graphics-backend hook is present.

diff --git a/dlls/ntdll/unix/loader.c b/dlls/ntdll/unix/loader.c
--- a/dlls/ntdll/unix/loader.c
+++ b/dlls/ntdll/unix/loader.c
@@ -383,6 +383,93 @@ static void prepend_dll_path( const char *path )
     if (path_len > dll_path_maxlen)
         dll_path_maxlen = path_len;
 }
+
+/*
+ * IgniteX per-process graphics routes.
+ *
+ * The Apple GPTK modules remain user supplied.  This code only gives a
+ * selected Windows executable priority access to their builtin module root;
+ * other processes in the same wineserver keep using the runtime's WineD3D.
+ */
+static BOOL ascii_token_matches_exe( const char *list, const WCHAR *image )
+{
+    const WCHAR *name = ntdll_wcsrchr( image, '\\' );
+
+    if (name) name++;
+    else name = image;
+
+    while (*list)
+    {
+        const char *start, *end, *p;
+        const WCHAR *q = name;
+
+        while (*list == ' ' || *list == '\t' || *list == ',' || *list == ';') list++;
+        start = list;
+        while (*list && *list != ',' && *list != ';') list++;
+        end = list;
+        while (end > start && (end[-1] == ' ' || end[-1] == '\t')) end--;
+
+        for (p = start; p < end && *q; p++, q++)
+        {
+            WCHAR a = *q, b = (unsigned char)*p;
+            if (a >= 'a' && a <= 'z') a -= 'a' - 'A';
+            if (b >= 'a' && b <= 'z') b -= 'a' - 'A';
+            if (a != b) break;
+        }
+        if (p == end && !*q) return TRUE;
+    }
+    return FALSE;
+}
+
+static BOOL ignitex_route_matches( const char *path, const char *executables )
+{
+    return path && path[0] == '/' && executables &&
+           ascii_token_matches_exe( executables, main_wargv[0] );
+}
+
+static void init_ignitex_graphics_route(void)
+{
+    static const WCHAR d3dmetal_overridesW[] =
+    {
+        'd','3','d','1','0',',','d','3','d','1','1',',','d','3','d','1','2',',',
+        'd','x','g','i','=','b',0
+    };
+    static const WCHAR dxmt_overridesW[] =
+    {
+        'd','3','d','1','0','c','o','r','e',',','d','3','d','1','1',',',
+        'd','x','g','i','=','b',0
+    };
+    const char *d3dmetal_path = getenv( "IGNITEX_D3DMETAL_DLL_PATH" );
+    const char *d3dmetal_executables = getenv( "IGNITEX_D3DMETAL_EXES" );
+    const char *dxmt_path = getenv( "IGNITEX_DXMT_DLL_PATH" );
+    const char *dxmt_executables = getenv( "IGNITEX_DXMT_EXES" );
+    BOOL d3dmetal_match = ignitex_route_matches( d3dmetal_path,
+                                                  d3dmetal_executables );
+    BOOL dxmt_match = ignitex_route_matches( dxmt_path, dxmt_executables );
+
+    if (d3dmetal_match && dxmt_match)
+    {
+        ERR( "refusing conflicting IgniteX graphics routes for %s\n",
+             debugstr_w( main_wargv[0] ));
+        return;
+    }
+    if (d3dmetal_match)
+    {
+        prepend_dll_path( d3dmetal_path );
+        add_load_order_override( d3dmetal_overridesW );
+        setenv( "CX_ACTIVE_GRAPHICS_BACKEND", "d3dmetal", 1 );
+        WARN( "using user-supplied D3DMetal modules for %s\n",
+              debugstr_w( main_wargv[0] ));
+    }
+    else if (dxmt_match)
+    {
+        prepend_dll_path( dxmt_path );
+        add_load_order_override( dxmt_overridesW );
+        setenv( "CX_ACTIVE_GRAPHICS_BACKEND", "dxmt", 1 );
+        WARN( "using receipt-verified DXMT modules for %s\n",
+              debugstr_w( main_wargv[0] ));
+    }
+}
 
 static void set_dll_path(void)
 {
@@ -2231,6 +2318,7 @@ NTSTATUS loader_init( CONTEXT *context, void **entry )
     init_startup_info();
     *(ULONG_PTR *)&peb->CloudFileFlags = get_image_address();
     set_load_order_app_name( main_wargv[0] );
+    init_ignitex_graphics_route();
     init_thread_stack( teb, 0, 0, 0 );
     NtCreateKeyedEvent( &keyed_event, GENERIC_READ | GENERIC_WRITE, NULL, 0 );
     load_ntdll();
diff --git a/dlls/ntdll/unix/unix_private.h b/dlls/ntdll/unix/unix_private.h
--- a/dlls/ntdll/unix/unix_private.h
+++ b/dlls/ntdll/unix/unix_private.h
@@ -559,6 +559,7 @@ struct loadorder_list
 };
 
 extern void set_load_order_app_name( const WCHAR *app_name );
+extern void add_load_order_override( const WCHAR *entry );
 extern enum loadorder get_load_order( const UNICODE_STRING *nt_name );
 
 static inline WCHAR ntdll_towupper( WCHAR ch )
diff --git a/dlls/win32u/vulkan.c b/dlls/win32u/vulkan.c
--- a/dlls/win32u/vulkan.c
+++ b/dlls/win32u/vulkan.c
@@ -3006,7 +3006,14 @@ static void vulkan_init_once(void)
     if (!(libvulkan = getenv( "CX_LIBVULKAN" )) ||
         !(graphics_backend = getenv( "CX_ACTIVE_GRAPHICS_BACKEND" )) ||
         strcmp( graphics_backend, "wined3d" ))
+    {
+#ifdef SONAME_LIBVULKAN
         libvulkan = SONAME_LIBVULKAN;
+#else
+        ERR( "No Vulkan loader was configured\n" );
+        return;
+#endif
+    }
     else
         ERR( "Using %s\n", libvulkan );
 
-- 
2.50.1