reactos/ntoskrnl/ke/i386/vdm.c

   1 /* $Id$
   2  *
   3  * COPYRIGHT:       See COPYING in the top level directory
   4  * PROJECT:         ReactOS kernel
   5  * FILE:            ntoskrnl/ke/i386/vdm.c
   6  * PURPOSE:         Virtual DOS machine support
   7  *
   8  * PROGRAMMERS:     David Welch (welch@mcmail.com)
   9  */
  10
  11 /* INCLUDES *****************************************************************/
  12
  13 #include <ntoskrnl.h>
  14 #include <internal/debug.h>
  15
  16 #if defined (ALLOC_PRAGMA)
  17 #pragma alloc_text(INIT, NtEarlyInitVdm)
  18 #endif
  19
  20
  21 /* GLOBALS *******************************************************************/
  22
  23 static UCHAR OrigIVT[1024];
  24 static UCHAR OrigBDA[256];
  25 /* static UCHAR OrigEBDA[]; */
  26
  27 extern VOID Ki386RetToV86Mode(PKV86M_REGISTERS InRegs,
  28                               PKV86M_REGISTERS OutRegs);
  29
  30 /* FUNCTIONS *****************************************************************/
  31
  32 VOID INIT_FUNCTION
  33 NtEarlyInitVdm(VOID)
  34 {
  35   /* GCC 3.4 warns if NULL is passed in parameter 2 to the standard function memcpy */
  36   PVOID start = (PVOID)0x0;
  37
  38   /*
  39    * Save various BIOS data tables. At this point the lower 4MB memory
  40    * map is still active so we can just copy the data from low memory.
  41    */
  42   memcpy(OrigIVT, start, 1024);
  43   memcpy(OrigBDA, (PVOID)0x400, 256);
  44 }
  45
  46 /*
  47  * @implemented
  48  */
  49 NTSTATUS STDCALL NtVdmControl(ULONG ControlCode,
  50                               PVOID ControlData)
  51 {
  52   KPROCESSOR_MODE PreviousMode;
  53   NTSTATUS Status = STATUS_SUCCESS;
  54
  55   PreviousMode = ExGetPreviousMode();
  56
  57   if (PreviousMode != KernelMode)
  58   {
  59     _SEH_TRY
  60     {
  61       switch (ControlCode)
  62       {
  63         case 0:
  64           ProbeForWrite(ControlData,
  65                         1024,
  66                         1);
  67           memcpy(ControlData, OrigIVT, 1024);
  68           break;
  69
  70         case 1:
  71           ProbeForWrite(ControlData,
  72                         256,
  73                         1);
  74           memcpy(ControlData, OrigBDA, 256);
  75           break;
  76
  77         case 2:
  78         {
  79           KV86M_REGISTERS V86Registers;
  80
  81           ProbeForWrite(ControlData,
  82                         sizeof(KV86M_REGISTERS),
  83                         1);
  84           memcpy(&V86Registers,
  85                  ControlData,
  86                  sizeof(KV86M_REGISTERS));
  87
  88           /* FIXME: This should use ->VdmObjects */
  89           KeGetCurrentProcess()->Unused = 1;
  90           Ki386RetToV86Mode(&V86Registers, &V86Registers);
  91
  92           /* FIXME: This should use ->VdmObjects */
  93           KeGetCurrentProcess()->Unused = 0;
  94
  95           memcpy(ControlData,
  96                  &V86Registers,
  97                  sizeof(KV86M_REGISTERS));
  98           break;
  99         }
 100       }
 101     }
 102     _SEH_HANDLE
 103     {
 104       Status = _SEH_GetExceptionCode();
 105     }
 106     _SEH_END;
 107   }
 108
 109   return Status;
 110 }
 111
 112 /* EOF */