dlls/krnl386.exe16/int25.c

   1 /*
   2  * DOS interrupt 25h handler
   3  *
   4  * Copyright 1997 Andreas Mohr
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  */
  20
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <fcntl.h>
  25
  26 #include "dosexe.h"
  27 #include "wine/debug.h"
  28
  29 WINE_DEFAULT_DEBUG_CHANNEL(int);
  30
  31
  32 /***********************************************************************
  33  *           DOSVM_RawRead
  34  *
  35  * Read raw sectors from a device.
  36  */
  37 BOOL DOSVM_RawRead(BYTE drive, DWORD begin, DWORD nr_sect, BYTE *dataptr, BOOL fake_success)
  38 {
  39     WCHAR root[] = {'\\','\\','.','\\','A',':',0};
  40     HANDLE h;
  41
  42     TRACE( "abs diskread, drive %d, sector %d, "
  43            "count %d, buffer %p\n",
  44            drive, begin, nr_sect, dataptr );
  45
  46     root[4] += drive;
  47     h = CreateFileW(root, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING,
  48                     FILE_FLAG_BACKUP_SEMANTICS, NULL);
  49     if (h != INVALID_HANDLE_VALUE)
  50     {
  51         DWORD r;
  52         SetFilePointer(h, begin * 512, NULL, SEEK_SET );
  53         /* FIXME: check errors */
  54         ReadFile(h, dataptr, nr_sect * 512, &r, NULL );
  55         CloseHandle(h);
  56     }
  57     else
  58     {
  59         memset( dataptr, 0, nr_sect * 512 );
  60         if (fake_success)
  61         {
  62             /* FIXME: explain what happens here */
  63             if (begin == 0 && nr_sect > 1) *(dataptr + 512) = 0xf8;
  64             if (begin == 1) *dataptr = 0xf8;
  65         }
  66         else
  67             return FALSE;
  68     }
  69
  70     return TRUE;
  71 }
  72
  73
  74 /**********************************************************************
  75  *          DOSVM_Int25Handler
  76  *
  77  * Handler for int 25h (absolute disk read).
  78  */
  79 void WINAPI DOSVM_Int25Handler( CONTEXT *context )
  80 {
  81     WCHAR drivespec[] = {'A', ':', '\\', 0};
  82     BYTE *dataptr = CTX_SEG_OFF_TO_LIN( context, context->SegDs, context->Ebx );
  83     DWORD begin;
  84     DWORD length;
  85
  86     drivespec[0] += AL_reg( context );
  87
  88     if (GetDriveTypeW( drivespec ) == DRIVE_NO_ROOT_DIR ||
  89         GetDriveTypeW( drivespec ) == DRIVE_UNKNOWN)
  90     {
  91         SET_CFLAG( context );
  92         SET_AX( context, 0x0201 ); /* unknown unit */
  93         return;
  94     }
  95
  96     if (CX_reg( context ) == 0xffff)
  97     {
  98         begin   = *(DWORD *)dataptr;
  99         length  = *(WORD *)(dataptr + 4);
 100         dataptr = (BYTE *)CTX_SEG_OFF_TO_LIN( context,
 101                                               *(WORD *)(dataptr + 8),
 102                                               *(DWORD *)(dataptr + 6) );
 103     }
 104     else
 105     {
 106         begin  = DX_reg( context );
 107         length = CX_reg( context );
 108     }
 109
 110     DOSVM_RawRead( AL_reg( context ), begin, length, dataptr, TRUE );
 111     RESET_CFLAG( context );
 112 }