[PATCH 0/1] MR5236: Draft: ntdll: Implement NtdllDefWindowProc_A().

[Aida Jonikienė (＠DodoGTA)]

I've tried implementing this before but importing user32 from ntdll isn't a reliable
thing (so I recently rewrote it using the ntdll equivalents of LoadLibrary() and GetProcAddress())

Note: This is a weird way to implement this function (Windows implements this
in ntdll instead) but that would probably require a user32/ntdll rewrite (so this
is the next best tning to get the application working)

[PATCH 1/1] ntdll: Implement NtdllDefWindowProc_A().

[Aida Jonikienė]

From: Aida Jonikienė

The Crinkler linker redirects the DefWindowProcA calls to the
NtdllDefWindowProc_A function (which doesn't exist on Wine)
and so it picks the first export in ntdll (which is A_SHAFinal right now)
which obviously causes a segfault (this is problematic for the application
listed in the bug report).

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=53321
---
 dlls/ntdll/misc.c     | 32 ++++++++++++++++++++++++++++++++
 dlls/ntdll/ntdll.spec |  1 +
 2 files changed, 33 insertions(+)

diff --git a/dlls/ntdll/misc.c b/dlls/ntdll/misc.c
index ab01c77531c..b5286fefd13 100644
--- a/dlls/ntdll/misc.c
+++ b/dlls/ntdll/misc.c
@@ -501,3 +501,35 @@ ULONG WINAPIV EtwTraceMessage( TRACEHANDLE handle, ULONG flags, LPGUID guid, /*U
     va_end( valist );
     return ret;
 }
+
+/******************************************************************************
+ *                  NtdllDefWindowProc_A (NTDLL.@)
+ */
+LRESULT WINAPI NtdllDefWindowProc_A( HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam )
+{
+    static LPARAM (WINAPI *pDefWindowProcA)(HWND,UINT,WPARAM,LPARAM); /* DefWindowProcA */
+
+    UNICODE_STRING name;
+    NTSTATUS status;
+    HMODULE module;
+
+    if (pDefWindowProcA) return pDefWindowProcA( hwnd, msg, wParam, lParam );
+
+    RtlCreateUnicodeString( &name, L"user32.dll" );
+    if (( status = LdrLoadDll( NULL, 0, &name, &module )))
+    {
+        ERR("Failed to load user32.dll, status %ld\n", status);
+        if (name.Buffer) RtlFreeUnicodeString( &name );
+        return 1; /* FIXME: Is this a good way to indicate failure? */
+    }
+
+    if (name.Buffer) RtlFreeUnicodeString( &name );
+    pDefWindowProcA = RtlFindExportedRoutineByName( module, "DefWindowProcA" );
+    if (!pDefWindowProcA)
+    {
+        ERR("Failed to load the function\n");
+        return 1;
+    }
+
+    return pDefWindowProcA( hwnd, msg, wParam, lParam );
+}
diff --git a/dlls/ntdll/ntdll.spec b/dlls/ntdll/ntdll.spec
index 66995346e57..7dde0c91297 100644
--- a/dlls/ntdll/ntdll.spec
+++ b/dlls/ntdll/ntdll.spec
@@ -209,6 +209,7 @@
 @ stdcall -syscall NtDeleteValueKey(long ptr)
 @ stdcall -syscall NtDeviceIoControlFile(long long ptr ptr ptr long ptr long ptr long)
 @ stdcall -syscall NtDisplayString(ptr)
+@ stdcall NtdllDefWindowProc_A(long long long long)
 @ stdcall -syscall NtDuplicateObject(long long long ptr long long long)
 @ stdcall -syscall NtDuplicateToken(long long ptr long long ptr)
 # @ stub NtEnumerateBootEntries

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about dlls/ntdll/ntdll.spec:
> @ stdcall -syscall NtDeleteValueKey(long ptr)
>  @ stdcall -syscall NtDeviceIoControlFile(long long ptr ptr ptr long ptr long ptr long)
>  @ stdcall -syscall NtDisplayString(ptr)
> +@ stdcall NtdllDefWindowProc_A(long long long long)

Instead of implementing it as a stub, you can scrub the implementation and just use forwarders instead.[^1][^2]

```suggestion:-0+0
@ stdcall NtdllDefWindowProc_A(long long long long) user32.DefWindowProcA
```

[^1]: [Exported functions that are really forwarders - The Old New Thing](https://devblogs.microsoft.com/oldnewthing/20060719-24/?p=30473)
[^2]: [DLL forwarding is not the same as delay-loading - The Old New Thing](https://devblogs.microsoft.com/oldnewthing/20080204-00/?p=23593)

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about dlls/ntdll/ntdll.spec:
> @ stdcall -syscall NtDeleteValueKey(long ptr)
>  @ stdcall -syscall NtDeviceIoControlFile(long long ptr ptr ptr long ptr long ptr long)
>  @ stdcall -syscall NtDisplayString(ptr)
> +@ stdcall NtdllDefWindowProc_A(long long long long)

Export symbols are case-sensitive: `Nta` goes after `NtZ` in lexicographical ordering.

This should go after `NtYieldExecution`, before `PfxFindPrefix`.

[Aida Jonikienė (＠DodoGTA)]

On Tue Mar  5 14:58:50 2024 +0000, Jinoh Kang wrote:
> Export symbols are case-sensitive: `Nta` goes after `NtZ` in
> lexicographical ordering.
> This should go after `NtYieldExecution`, before `PfxFindPrefix`.

This will be fixed when the MR gets updated

[Aida Jonikienė (＠DodoGTA)]

On Tue Mar  5 14:55:56 2024 +0000, Jinoh Kang wrote:
> Instead of implementing it as a stub, you can scrub the implementation
> and just use forwarders instead.[^1][^2]
> @ stdcall NtdllDefWindowProc_A(long long long long) user32.DefWindowProcA
>
> [^1]: [Exported functions that are really forwarders - The Old New Thing](https://devblogs.microsoft.com/oldnewthing/20060719-24/?p=30473)
> [^2]: [DLL forwarding is not the same as delay-loading - The Old New Thing](https://devblogs.microsoft.com/oldnewthing/20080204-00/?p=23593)

Unfortunately using this method doesn't work in this case (I get `0158:err:seh:dispatch_user_callback ignoring exception c0000005` when that function gets called)