From 40c42305c31dd4e1f39c6f6432ecd4cf422094e8 Mon Sep 17 00:00:00 2001
From: James Tabor <james.tabor@reactos.org>
Date: Fri, 21 Jun 2019 13:10:03 -0500
Subject: [PATCH] [Win32SS] Add Driver Callback

Add user driver callback to be used later on.
---
 win32ss/include/callback.h         |  5 ++++-
 win32ss/user/ntuser/callback.c     | 25 +++++++++++++++++++++++++
 win32ss/user/user32/misc/dllmain.c |  7 +++++++
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/win32ss/include/callback.h b/win32ss/include/callback.h
index 75eda686a2d..5b6f49ce3a2 100644
--- a/win32ss/include/callback.h
+++ b/win32ss/include/callback.h
@@ -18,7 +18,8 @@
 #define USER32_CALLBACK_DDEGET                (14)
 #define USER32_CALLBACK_SETOBM                (15)
 #define USER32_CALLBACK_LPK                   (16)
-#define USER32_CALLBACK_MAXIMUM               (16)
+#define USER32_CALLBACK_UMPD                  (17)
+#define USER32_CALLBACK_MAXIMUM               (17)
 
 typedef struct _WINDOWPROC_CALLBACK_ARGUMENTS
 {
@@ -186,4 +187,6 @@ NTSTATUS WINAPI
 User32CallOBMFromKernel(PVOID Arguments, ULONG ArgumentLength);
 NTSTATUS WINAPI
 User32CallLPKFromKernel(PVOID Arguments, ULONG ArgumentLength);
+NTSTATUS WINAPI
+User32CallUMPDFromKernel(PVOID Arguments, ULONG ArgumentLength);
 #endif /* __INCLUDE_USER32_CALLBACK_H */
diff --git a/win32ss/user/ntuser/callback.c b/win32ss/user/ntuser/callback.c
index fb9fc9692d5..151a2f12af9 100644
--- a/win32ss/user/ntuser/callback.c
+++ b/win32ss/user/ntuser/callback.c
@@ -1208,5 +1208,30 @@ co_IntSetupOBM(VOID)
    IntCbFreeMemory(Argument);
 }
 
+LRESULT
+APIENTRY
+co_UserCBClientPrinterThunk( PVOID pkt, INT InSize, PVOID pvOutData, INT OutSize )
+{
+   ULONG ResultLength;
+   PVOID ResultPointer;
+   NTSTATUS Status;
+   UserLeaveCo();
+
+   Status = KeUserModeCallback(USER32_CALLBACK_UMPD,
+                               0,
+                               0,
+                               &ResultPointer,
+                               &ResultLength);
+
+
+   UserEnterCo();
+
+   if (!NT_SUCCESS(Status))
+   {
+      ERR("User UMPD callback failed!\n");
+   }
+
+   return 0;
+}
 
 /* EOF */
diff --git a/win32ss/user/user32/misc/dllmain.c b/win32ss/user/user32/misc/dllmain.c
index e329b85229b..a7d0f098b49 100644
--- a/win32ss/user/user32/misc/dllmain.c
+++ b/win32ss/user/user32/misc/dllmain.c
@@ -206,6 +206,7 @@ PVOID apfnDispatch[USER32_CALLBACK_MAXIMUM + 1] =
     User32CallDDEGetFromKernel,
     User32CallOBMFromKernel,
     User32CallLPKFromKernel,
+    User32CallUMPDFromKernel,
 };
 
 
@@ -663,3 +664,9 @@ NTSTATUS WINAPI User32CallLPKFromKernel(PVOID Arguments, ULONG ArgumentLength)
 
     return ZwCallbackReturn(&bResult, sizeof(BOOL), STATUS_SUCCESS);
 }
+
+NTSTATUS WINAPI User32CallUMPDFromKernel(PVOID Arguments, ULONG ArgumentLength)
+{
+    // = GdiPrinterThunk( , , );
+    return ZwCallbackReturn(Arguments, ArgumentLength, STATUS_SUCCESS);
+}