dlls/kernel/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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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 "winreg.h"
  37 #include "excpt.h"
  38 #include "winternl.h"
  39 #include "wine/winbase16.h"
  40
  41 #include "kernel_private.h"
  42 #include "toolhelp.h"
  43 #include "wine/debug.h"
  44
  45 WINE_DEFAULT_DEBUG_CHANNEL(dosmem);
  46 WINE_DECLARE_DEBUG_CHANNEL(selector);
  47
  48 WORD DOSMEM_0000H;        /* segment at 0:0 */
  49 WORD DOSMEM_BiosDataSeg;  /* BIOS data segment at 0x40:0 */
  50 WORD DOSMEM_BiosSysSeg;   /* BIOS ROM segment at 0xf000:0 */
  51
  52 /* DOS memory highest address (including HMA) */
  53 #define DOSMEM_SIZE             0x110000
  54 #define DOSMEM_64KB             0x10000
  55
  56 /* when looking at DOS and real mode memory, we activate in three different
  57  * modes, depending the situation.
  58  * 1/ By default (protected mode), the first MB of memory (actually 0x110000,
  59  *    when you also look at the HMA part) is always reserved, whatever you do.
  60  *    We allocated some PM selectors to this memory, even if this area is not
  61  *    committed at startup
  62  * 2/ if a program tries to use the memory through the selectors, we actually
  63  *    commit this memory, made of: BIOS segment, but also some system
  64  *    information, usually low in memory that we map for the circumstance also
  65  *    in the BIOS segment, so that we keep the low memory protected (for NULL
  66  *    pointer deref catching for example). In this case, we're still in PM
  67  *    mode, accessing part of the "physical" real mode memory. In fact, we don't
  68  *    map all the first meg, we keep 64k uncommitted to still catch NULL
  69  *    pointers dereference
  70  * 3/ if the process enters the real mode, then we (also) commit the full first
  71  *    MB of memory (and also initialize the DOS structures in it).
  72  */
  73
  74 /* DOS memory base (linear in process address space) */
  75 static char *DOSMEM_dosmem;
  76 /* number of bytes protected from _dosmem. 0 when DOS memory is initialized,
  77  * 64k otherwise to trap NULL pointers deref */
  78 static DWORD DOSMEM_protect;
  79
  80 static LONG WINAPI dosmem_handler(EXCEPTION_POINTERS* except);
  81
  82 struct winedos_exports winedos;
  83
  84 void load_winedos(void)
  85 {
  86     static HANDLE       hRunOnce /* = 0 */;
  87     static HMODULE      hWineDos /* = 0 */;
  88
  89     /* FIXME: this isn't 100% thread safe, as we won't catch access to 1MB while
  90      * loading winedos (and may return uninitialized valued)
  91      */
  92     if (hWineDos) return;
  93     if (hRunOnce == 0)
  94     {
  95         HANDLE hEvent = CreateEventW( NULL, TRUE, FALSE, NULL );
  96         if (InterlockedCompareExchangePointer( (PVOID)&hRunOnce, hEvent, 0 ) == 0)
  97         {
  98             HMODULE hModule;
  99
 100             /* ok, we're the winning thread */
 101             VirtualProtect( DOSMEM_dosmem + DOSMEM_protect,
 102                             DOSMEM_SIZE - DOSMEM_protect,
 103                             PAGE_EXECUTE_READWRITE, NULL );
 104             if (!(hModule = LoadLibraryA( "winedos.dll" )))
 105             {
 106                 ERR("Could not load winedos.dll, DOS subsystem unavailable\n");
 107                 hWineDos = (HMODULE)1; /* not to try to load it again */
 108                 return;
 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             RtlRemoveVectoredExceptionHandler( dosmem_handler );
 121             hWineDos = hModule;
 122             SetEvent( hRunOnce );
 123             return;
 124         }
 125         /* someone beat us here... */
 126         CloseHandle( hEvent );
 127     }
 128
 129     /* and wait for the winner to have finished */
 130     WaitForSingleObject( hRunOnce, INFINITE );
 131 }
 132
 133 /******************************************************************
 134  *              dosmem_handler
 135  *
 136  * Handler to catch access to our 1MB address space reserved for real memory
 137  */
 138 static LONG WINAPI dosmem_handler(EXCEPTION_POINTERS* except)
 139 {
 140     if (except->ExceptionRecord->ExceptionCode == EXCEPTION_ACCESS_VIOLATION)
 141     {
 142         DWORD   addr = except->ExceptionRecord->ExceptionInformation[1];
 143         if (addr >= (ULONG_PTR)DOSMEM_dosmem + DOSMEM_protect &&
 144             addr < (ULONG_PTR)DOSMEM_dosmem + DOSMEM_SIZE)
 145         {
 146             load_winedos();
 147             return EXCEPTION_CONTINUE_EXECUTION;
 148         }
 149     }
 150     return EXCEPTION_CONTINUE_SEARCH;
 151 }
 152
 153 /**********************************************************************
 154  *              setup_dos_mem
 155  *
 156  * Setup the first megabyte for DOS memory access
 157  */
 158 static char* setup_dos_mem(void)
 159 {
 160     int sys_offset = 0;
 161     int page_size = getpagesize();
 162     void *addr = NULL;
 163
 164     if (wine_mmap_is_in_reserved_area( NULL, DOSMEM_SIZE ) != 1)
 165     {
 166         addr = wine_anon_mmap( (void *)page_size, DOSMEM_SIZE-page_size,
 167                                PROT_READ | PROT_WRITE | PROT_EXEC, 0 );
 168         if (addr == (void *)page_size) addr = NULL; /* we got what we wanted */
 169         else munmap( addr, DOSMEM_SIZE - page_size );
 170     }
 171
 172     if (!addr)
 173     {
 174         /* now reserve from address 0 */
 175         wine_anon_mmap( NULL, DOSMEM_SIZE, 0, MAP_FIXED );
 176
 177         /* inform the memory manager that there is a mapping here, but don't commit yet */
 178         VirtualAlloc( NULL, DOSMEM_SIZE, MEM_RESERVE | MEM_SYSTEM, PAGE_NOACCESS );
 179         sys_offset = 0xf0000;
 180         DOSMEM_protect = DOSMEM_64KB;
 181     }
 182     else
 183     {
 184         ERR("Cannot use first megabyte for DOS address space, please report\n" );
 185         /* allocate the DOS area somewhere else */
 186         addr = VirtualAlloc( NULL, DOSMEM_SIZE, MEM_RESERVE, PAGE_NOACCESS );
 187         if (!addr)
 188         {
 189             ERR( "Cannot allocate DOS memory\n" );
 190             ExitProcess(1);
 191         }
 192     }
 193     DOSMEM_dosmem = addr;
 194     RtlAddVectoredExceptionHandler(FALSE, dosmem_handler);
 195     return (char*)addr + sys_offset;
 196 }
 197
 198
 199 /***********************************************************************
 200  *           DOSMEM_Init
 201  *
 202  * Create the dos memory segments, and store them into the KERNEL
 203  * exported values.
 204  */
 205 BOOL DOSMEM_Init(void)
 206 {
 207     char*       sysmem = setup_dos_mem();
 208
 209     DOSMEM_0000H = GLOBAL_CreateBlock( GMEM_FIXED, sysmem,
 210                                        DOSMEM_64KB, 0, WINE_LDT_FLAGS_DATA );
 211     DOSMEM_BiosDataSeg = GLOBAL_CreateBlock( GMEM_FIXED, sysmem + 0x400,
 212                                              0x100, 0, WINE_LDT_FLAGS_DATA );
 213     DOSMEM_BiosSysSeg = GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_dosmem + 0xf0000,
 214                                             DOSMEM_64KB, 0, WINE_LDT_FLAGS_DATA );
 215
 216     return TRUE;
 217 }
 218
 219 /***********************************************************************
 220  *           DOSMEM_MapLinearToDos
 221  *
 222  * Linear address to the DOS address space.
 223  */
 224 UINT DOSMEM_MapLinearToDos(LPVOID ptr)
 225 {
 226     if (((char*)ptr >= DOSMEM_dosmem) &&
 227         ((char*)ptr < DOSMEM_dosmem + DOSMEM_SIZE))
 228           return (UINT)ptr - (UINT)DOSMEM_dosmem;
 229     return (UINT)ptr;
 230 }
 231
 232
 233 /***********************************************************************
 234  *           DOSMEM_MapDosToLinear
 235  *
 236  * DOS linear address to the linear address space.
 237  */
 238 LPVOID DOSMEM_MapDosToLinear(UINT ptr)
 239 {
 240     if (ptr < DOSMEM_SIZE) return (LPVOID)(ptr + (UINT)DOSMEM_dosmem);
 241     return (LPVOID)ptr;
 242 }
 243
 244
 245 /***********************************************************************
 246  *           DOSMEM_MapRealToLinear
 247  *
 248  * Real mode DOS address into a linear pointer
 249  */
 250 LPVOID DOSMEM_MapRealToLinear(DWORD x)
 251 {
 252    LPVOID       lin;
 253
 254    lin = DOSMEM_dosmem + HIWORD(x) * 16 + LOWORD(x);
 255    TRACE_(selector)("(0x%08lx) returns %p.\n", x, lin );
 256    return lin;
 257 }
 258
 259 /***********************************************************************
 260  *           DOSMEM_AllocSelector
 261  *
 262  * Allocates a protected mode selector for a realmode segment.
 263  */
 264 WORD DOSMEM_AllocSelector(WORD realsel)
 265 {
 266         HMODULE16 hModule = GetModuleHandle16("KERNEL");
 267         WORD    sel;
 268
 269         sel=GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_dosmem+realsel*16, DOSMEM_64KB,
 270                                 hModule, WINE_LDT_FLAGS_DATA );
 271         TRACE_(selector)("(0x%04x) returns 0x%04x.\n", realsel,sel);
 272         return sel;
 273 }