dlls/kernel32/dosmem.c

   1 /*
   2  * DOS memory emulation
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  * Copyright 1996 Marcus Meissner
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  20  */
  21
  22 #include "config.h"
  23 #include "wine/port.h"
  24
  25 #include <signal.h>
  26 #include <stdarg.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sys/types.h>
  30 #ifdef HAVE_SYS_MMAN_H
  31 # include <sys/mman.h>
  32 #endif
  33
  34 #include "windef.h"
  35 #include "winbase.h"
  36 #include "excpt.h"
  37 #include "winternl.h"
  38 #include "wine/winbase16.h"
  39
  40 #include "kernel_private.h"
  41 #include "toolhelp.h"
  42 #include "wine/debug.h"
  43
  44 WINE_DEFAULT_DEBUG_CHANNEL(dosmem);
  45 WINE_DECLARE_DEBUG_CHANNEL(selector);
  46
  47 WORD DOSMEM_0000H;        /* segment at 0:0 */
  48 WORD DOSMEM_BiosDataSeg;  /* BIOS data segment at 0x40:0 */
  49 WORD DOSMEM_BiosSysSeg;   /* BIOS ROM segment at 0xf000:0 */
  50
  51 /* DOS memory highest address (including HMA) */
  52 #define DOSMEM_SIZE             0x110000
  53 #define DOSMEM_64KB             0x10000
  54
  55 /* when looking at DOS and real mode memory, we activate in three different
  56  * modes, depending the situation.
  57  * 1/ By default (protected mode), the first MB of memory (actually 0x110000,
  58  *    when you also look at the HMA part) is always reserved, whatever you do.
  59  *    We allocated some PM selectors to this memory, even if this area is not
  60  *    committed at startup
  61  * 2/ if a program tries to use the memory through the selectors, we actually
  62  *    commit this memory, made of: BIOS segment, but also some system
  63  *    information, usually low in memory that we map for the circumstance also
  64  *    in the BIOS segment, so that we keep the low memory protected (for NULL
  65  *    pointer deref catching for example). In this case, we're still in PM
  66  *    mode, accessing part of the "physical" real mode memory. In fact, we don't
  67  *    map all the first meg, we keep 64k uncommitted to still catch NULL
  68  *    pointers dereference
  69  * 3/ if the process enters the real mode, then we (also) commit the full first
  70  *    MB of memory (and also initialize the DOS structures in it).
  71  */
  72
  73 /* DOS memory base (linear in process address space) */
  74 static char *DOSMEM_dosmem;
  75 /* number of bytes protected from _dosmem. 0 when DOS memory is initialized,
  76  * 64k otherwise to trap NULL pointers deref */
  77 static DWORD DOSMEM_protect;
  78
  79 static LONG WINAPI dosmem_handler(EXCEPTION_POINTERS* except);
  80
  81 struct winedos_exports winedos;
  82
  83 BOOL load_winedos(void)
  84 {
  85     static HANDLE       hRunOnce /* = 0 */;
  86     static HMODULE      hWineDos /* = 0 */;
  87
  88     /* FIXME: this isn't 100% thread safe, as we won't catch access to 1MB while
  89      * loading winedos (and may return uninitialized valued)
  90      */
  91     if (hWineDos) goto done;
  92     if (hRunOnce == 0)
  93     {
  94         HANDLE hEvent = CreateEventW( NULL, TRUE, FALSE, NULL );
  95         if (InterlockedCompareExchangePointer( &hRunOnce, hEvent, 0 ) == 0)
  96         {
  97             HMODULE hModule;
  98
  99             /* ok, we're the winning thread */
 100             if (!VirtualProtect( DOSMEM_dosmem + DOSMEM_protect,
 101                                  DOSMEM_SIZE - DOSMEM_protect,
 102                                  PAGE_READWRITE, NULL ) ||
 103                 !(hModule = LoadLibraryA( "winedos.dll" )))
 104             {
 105                 ERR("Could not load winedos.dll, DOS subsystem unavailable\n");
 106                 hModule = (HMODULE)1; /* not to try to load it again */
 107             }
 108             else
 109             {
 110 #define GET_ADDR(func)  winedos.func = (void *)GetProcAddress( hModule, #func );
 111                 GET_ADDR(AllocDosBlock);
 112                 GET_ADDR(FreeDosBlock);
 113                 GET_ADDR(ResizeDosBlock);
 114                 GET_ADDR(inport);
 115                 GET_ADDR(outport);
 116                 GET_ADDR(EmulateInterruptPM);
 117                 GET_ADDR(CallBuiltinHandler);
 118                 GET_ADDR(BiosTick);
 119 #undef GET_ADDR
 120             }
 121             RtlRemoveVectoredExceptionHandler( dosmem_handler );
 122             hWineDos = hModule;
 123             SetEvent( hRunOnce );
 124             goto done;
 125         }
 126         /* someone beat us here... */
 127         CloseHandle( hEvent );
 128     }
 129
 130     /* and wait for the winner to have finished */
 131     WaitForSingleObject( hRunOnce, INFINITE );
 132  done:
 133     return (hWineDos != (HMODULE)1);
 134 }
 135
 136 /******************************************************************
 137  *              dosmem_handler
 138  *
 139  * Handler to catch access to our 1MB address space reserved for real memory
 140  */
 141 static LONG WINAPI dosmem_handler(EXCEPTION_POINTERS* except)
 142 {
 143     if (except->ExceptionRecord->ExceptionCode == EXCEPTION_ACCESS_VIOLATION)
 144     {
 145         char *addr = (char *)except->ExceptionRecord->ExceptionInformation[1];
 146         if (addr >= DOSMEM_dosmem + DOSMEM_protect && addr < DOSMEM_dosmem + DOSMEM_SIZE)
 147         {
 148             if (load_winedos()) return EXCEPTION_CONTINUE_EXECUTION;
 149         }
 150     }
 151     return EXCEPTION_CONTINUE_SEARCH;
 152 }
 153
 154 /***********************************************************************
 155  *           DOSMEM_Init
 156  *
 157  * Create the dos memory segments, and store them into the KERNEL
 158  * exported values.
 159  */
 160 BOOL DOSMEM_Init(void)
 161 {
 162     char *sysmem;
 163     void *addr = (void *)1;
 164     SIZE_T size = DOSMEM_SIZE - 1;
 165
 166     if (NtAllocateVirtualMemory( GetCurrentProcess(), &addr, 0, &size,
 167                                  MEM_RESERVE | MEM_COMMIT, PAGE_NOACCESS ))
 168     {
 169         ERR( "Cannot allocate DOS memory\n" );
 170         ExitProcess(1);
 171     }
 172
 173     if (addr <= (void *)DOSMEM_64KB)
 174     {
 175         DOSMEM_dosmem = 0;
 176         DOSMEM_protect = DOSMEM_64KB;
 177         sysmem = (char *)0xf0000;  /* store sysmem in high addresses for now */
 178     }
 179     else
 180     {
 181         WARN( "First megabyte not available for DOS address space.\n" );
 182         DOSMEM_dosmem = addr;
 183         DOSMEM_protect = 0;
 184         sysmem = DOSMEM_dosmem;
 185     }
 186
 187     RtlAddVectoredExceptionHandler(FALSE, dosmem_handler);
 188     DOSMEM_0000H = GLOBAL_CreateBlock( GMEM_FIXED, sysmem,
 189                                        DOSMEM_64KB, 0, WINE_LDT_FLAGS_DATA );
 190     DOSMEM_BiosDataSeg = GLOBAL_CreateBlock( GMEM_FIXED, sysmem + 0x400,
 191                                              0x100, 0, WINE_LDT_FLAGS_DATA );
 192     DOSMEM_BiosSysSeg = GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_dosmem + 0xf0000,
 193                                             DOSMEM_64KB, 0, WINE_LDT_FLAGS_DATA );
 194
 195     return TRUE;
 196 }
 197
 198 /***********************************************************************
 199  *           DOSMEM_MapLinearToDos
 200  *
 201  * Linear address to the DOS address space.
 202  */
 203 UINT DOSMEM_MapLinearToDos(LPVOID ptr)
 204 {
 205     if (((char*)ptr >= DOSMEM_dosmem) &&
 206         ((char*)ptr < DOSMEM_dosmem + DOSMEM_SIZE))
 207           return (char *)ptr - DOSMEM_dosmem;
 208     return (UINT)ptr;
 209 }
 210
 211
 212 /***********************************************************************
 213  *           DOSMEM_MapDosToLinear
 214  *
 215  * DOS linear address to the linear address space.
 216  */
 217 LPVOID DOSMEM_MapDosToLinear(UINT ptr)
 218 {
 219     if (ptr < DOSMEM_SIZE) return DOSMEM_dosmem + ptr;
 220     return (LPVOID)ptr;
 221 }
 222
 223
 224 /***********************************************************************
 225  *           DOSMEM_MapRealToLinear
 226  *
 227  * Real mode DOS address into a linear pointer
 228  */
 229 LPVOID DOSMEM_MapRealToLinear(DWORD x)
 230 {
 231    LPVOID       lin;
 232
 233    lin = DOSMEM_dosmem + HIWORD(x) * 16 + LOWORD(x);
 234    TRACE_(selector)("(0x%08x) returns %p.\n", x, lin );
 235    return lin;
 236 }