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 "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 void 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) return;
  92     if (hRunOnce == 0)
  93     {
  94         HANDLE hEvent = CreateEventW( NULL, TRUE, FALSE, NULL );
  95         if (InterlockedCompareExchangePointer( (PVOID)&hRunOnce, hEvent, 0 ) == 0)
  96         {
  97             HMODULE hModule;
  98
  99             /* ok, we're the winning thread */
 100             VirtualProtect( DOSMEM_dosmem + DOSMEM_protect,
 101                             DOSMEM_SIZE - DOSMEM_protect,
 102                             PAGE_EXECUTE_READWRITE, NULL );
 103             if (!(hModule = LoadLibraryA( "winedos.dll" )))
 104             {
 105                 ERR("Could not load winedos.dll, DOS subsystem unavailable\n");
 106                 hWineDos = (HMODULE)1; /* not to try to load it again */
 107                 return;
 108             }
 109 #define GET_ADDR(func)  winedos.func = (void *)GetProcAddress( hModule, #func );
 110     GET_ADDR(AllocDosBlock);
 111     GET_ADDR(FreeDosBlock);
 112     GET_ADDR(ResizeDosBlock);
 113     GET_ADDR(inport);
 114     GET_ADDR(outport);
 115     GET_ADDR(EmulateInterruptPM);
 116     GET_ADDR(CallBuiltinHandler);
 117     GET_ADDR(BiosTick);
 118 #undef GET_ADDR
 119             RtlRemoveVectoredExceptionHandler( dosmem_handler );
 120             hWineDos = hModule;
 121             SetEvent( hRunOnce );
 122             return;
 123         }
 124         /* someone beat us here... */
 125         CloseHandle( hEvent );
 126     }
 127
 128     /* and wait for the winner to have finished */
 129     WaitForSingleObject( hRunOnce, INFINITE );
 130 }
 131
 132 /******************************************************************
 133  *              dosmem_handler
 134  *
 135  * Handler to catch access to our 1MB address space reserved for real memory
 136  */
 137 static LONG WINAPI dosmem_handler(EXCEPTION_POINTERS* except)
 138 {
 139     if (except->ExceptionRecord->ExceptionCode == EXCEPTION_ACCESS_VIOLATION)
 140     {
 141         DWORD   addr = except->ExceptionRecord->ExceptionInformation[1];
 142         if (addr >= (ULONG_PTR)DOSMEM_dosmem + DOSMEM_protect &&
 143             addr < (ULONG_PTR)DOSMEM_dosmem + DOSMEM_SIZE)
 144         {
 145             load_winedos();
 146             return EXCEPTION_CONTINUE_EXECUTION;
 147         }
 148     }
 149     return EXCEPTION_CONTINUE_SEARCH;
 150 }
 151
 152 /**********************************************************************
 153  *              setup_dos_mem
 154  *
 155  * Setup the first megabyte for DOS memory access
 156  */
 157 static char* setup_dos_mem(void)
 158 {
 159     int sys_offset = 0;
 160     int page_size = getpagesize();
 161     void *addr = NULL;
 162
 163     if (wine_mmap_is_in_reserved_area( NULL, DOSMEM_SIZE ) != 1)
 164     {
 165         addr = wine_anon_mmap( (void *)page_size, DOSMEM_SIZE-page_size,
 166                                PROT_READ | PROT_WRITE | PROT_EXEC, 0 );
 167         if (addr == (void *)page_size) addr = NULL; /* we got what we wanted */
 168         else munmap( addr, DOSMEM_SIZE - page_size );
 169     }
 170
 171     if (!addr)
 172     {
 173         /* now reserve from address 0 */
 174         wine_anon_mmap( NULL, DOSMEM_SIZE, 0, MAP_FIXED );
 175
 176         /* inform the memory manager that there is a mapping here, but don't commit yet */
 177         VirtualAlloc( NULL, DOSMEM_SIZE, MEM_RESERVE | MEM_SYSTEM, PAGE_NOACCESS );
 178         sys_offset = 0xf0000;
 179         DOSMEM_protect = DOSMEM_64KB;
 180     }
 181     else
 182     {
 183         ERR("Cannot use first megabyte for DOS address space, please report\n" );
 184         /* allocate the DOS area somewhere else */
 185         addr = VirtualAlloc( NULL, DOSMEM_SIZE, MEM_RESERVE, PAGE_NOACCESS );
 186         if (!addr)
 187         {
 188             ERR( "Cannot allocate DOS memory\n" );
 189             ExitProcess(1);
 190         }
 191     }
 192     DOSMEM_dosmem = addr;
 193     RtlAddVectoredExceptionHandler(FALSE, dosmem_handler);
 194     return (char*)addr + sys_offset;
 195 }
 196
 197
 198 /***********************************************************************
 199  *           DOSMEM_Init
 200  *
 201  * Create the dos memory segments, and store them into the KERNEL
 202  * exported values.
 203  */
 204 BOOL DOSMEM_Init(void)
 205 {
 206     char*       sysmem = setup_dos_mem();
 207
 208     DOSMEM_0000H = GLOBAL_CreateBlock( GMEM_FIXED, sysmem,
 209                                        DOSMEM_64KB, 0, WINE_LDT_FLAGS_DATA );
 210     DOSMEM_BiosDataSeg = GLOBAL_CreateBlock( GMEM_FIXED, sysmem + 0x400,
 211                                              0x100, 0, WINE_LDT_FLAGS_DATA );
 212     DOSMEM_BiosSysSeg = GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_dosmem + 0xf0000,
 213                                             DOSMEM_64KB, 0, WINE_LDT_FLAGS_DATA );
 214
 215     return TRUE;
 216 }
 217
 218 /***********************************************************************
 219  *           DOSMEM_MapLinearToDos
 220  *
 221  * Linear address to the DOS address space.
 222  */
 223 UINT DOSMEM_MapLinearToDos(LPVOID ptr)
 224 {
 225     if (((char*)ptr >= DOSMEM_dosmem) &&
 226         ((char*)ptr < DOSMEM_dosmem + DOSMEM_SIZE))
 227           return (UINT)ptr - (UINT)DOSMEM_dosmem;
 228     return (UINT)ptr;
 229 }
 230
 231
 232 /***********************************************************************
 233  *           DOSMEM_MapDosToLinear
 234  *
 235  * DOS linear address to the linear address space.
 236  */
 237 LPVOID DOSMEM_MapDosToLinear(UINT ptr)
 238 {
 239     if (ptr < DOSMEM_SIZE) return (LPVOID)(ptr + (UINT)DOSMEM_dosmem);
 240     return (LPVOID)ptr;
 241 }
 242
 243
 244 /***********************************************************************
 245  *           DOSMEM_MapRealToLinear
 246  *
 247  * Real mode DOS address into a linear pointer
 248  */
 249 LPVOID DOSMEM_MapRealToLinear(DWORD x)
 250 {
 251    LPVOID       lin;
 252
 253    lin = DOSMEM_dosmem + HIWORD(x) * 16 + LOWORD(x);
 254    TRACE_(selector)("(0x%08lx) returns %p.\n", x, lin );
 255    return lin;
 256 }
 257
 258 /***********************************************************************
 259  *           DOSMEM_AllocSelector
 260  *
 261  * Allocates a protected mode selector for a realmode segment.
 262  */
 263 WORD DOSMEM_AllocSelector(WORD realsel)
 264 {
 265         HMODULE16 hModule = GetModuleHandle16("KERNEL");
 266         WORD    sel;
 267
 268         sel=GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_dosmem+realsel*16, DOSMEM_64KB,
 269                                 hModule, WINE_LDT_FLAGS_DATA );
 270         TRACE_(selector)("(0x%04x) returns 0x%04x.\n", realsel,sel);
 271         return sel;
 272 }