dlls/krnl386.exe16/dosexe.c

   1 /*
   2  * DOS (MZ) loader
   3  *
   4  * Copyright 1998 Ove Kåven
   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  * Note: This code hasn't been completely cleaned up yet.
  21  */
  22
  23 #include "config.h"
  24 #include "wine/port.h"
  25
  26 #include <stdarg.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <fcntl.h>
  31 #include <signal.h>
  32 #ifdef HAVE_UNISTD_H
  33 # include <unistd.h>
  34 #endif
  35 #include <sys/types.h>
  36 #ifdef HAVE_SYS_STAT_H
  37 # include <sys/stat.h>
  38 #endif
  39 #ifdef HAVE_SYS_TIME_H
  40 # include <sys/time.h>
  41 #endif
  42 #include "windef.h"
  43 #include "winbase.h"
  44 #include "wine/winbase16.h"
  45 #include "wingdi.h"
  46 #include "winuser.h"
  47 #include "winerror.h"
  48 #include "wine/debug.h"
  49 #include "kernel16_private.h"
  50 #include "dosexe.h"
  51 #include "vga.h"
  52
  53 WINE_DEFAULT_DEBUG_CHANNEL(module);
  54
  55 static BOOL DOSVM_isdosexe;
  56
  57 /**********************************************************************
  58  *          DOSVM_IsWin16
  59  *
  60  * Return TRUE if we are in Windows process.
  61  */
  62 BOOL DOSVM_IsWin16(void)
  63 {
  64   return !DOSVM_isdosexe;
  65 }
  66
  67 /**********************************************************************
  68  *          DOSVM_Exit
  69  */
  70 void DOSVM_Exit( WORD retval )
  71 {
  72     DWORD count;
  73
  74     ReleaseThunkLock( &count );
  75     ExitThread( retval );
  76 }
  77
  78
  79 #ifdef MZ_SUPPORTED
  80
  81 #define BIOS_DATA_SEGMENT 0x40
  82 #define PSP_SIZE 0x10
  83
  84 #define SEG16(ptr,seg) ((LPVOID)((BYTE*)ptr+((DWORD)(seg)<<4)))
  85 #define SEGPTR16(ptr,segptr) ((LPVOID)((BYTE*)ptr+((DWORD)SELECTOROF(segptr)<<4)+OFFSETOF(segptr)))
  86
  87 /* structures for EXEC */
  88
  89 #include "pshpack1.h"
  90
  91 typedef struct {
  92   WORD env_seg;
  93   DWORD cmdline;
  94   DWORD fcb1;
  95   DWORD fcb2;
  96   WORD init_sp;
  97   WORD init_ss;
  98   WORD init_ip;
  99   WORD init_cs;
 100 } ExecBlock;
 101
 102 typedef struct {
 103   WORD load_seg;
 104   WORD rel_seg;
 105 } OverlayBlock;
 106
 107 #include "poppack.h"
 108
 109 /* global variables */
 110
 111 pid_t dosvm_pid;
 112
 113 static WORD init_cs,init_ip,init_ss,init_sp;
 114 static HANDLE dosvm_thread, loop_thread;
 115 static DWORD dosvm_tid, loop_tid;
 116
 117 static DWORD MZ_Launch( LPCSTR cmdtail, int length );
 118 static BOOL MZ_InitTask(void);
 119
 120 static void MZ_CreatePSP( LPVOID lpPSP, WORD env, WORD par )
 121 {
 122   PDB16*psp=lpPSP;
 123
 124   psp->int20=0x20CD; /* int 20 */
 125   /* some programs use this to calculate how much memory they need */
 126   psp->nextParagraph=0x9FFF; /* FIXME: use a real value */
 127   /* FIXME: dispatcher */
 128   psp->savedint22 = DOSVM_GetRMHandler(0x22);
 129   psp->savedint23 = DOSVM_GetRMHandler(0x23);
 130   psp->savedint24 = DOSVM_GetRMHandler(0x24);
 131   psp->parentPSP=par;
 132   psp->environment=env;
 133   /* FIXME: more PSP stuff */
 134 }
 135
 136 static void MZ_FillPSP( LPVOID lpPSP, LPCSTR cmdtail, int length )
 137 {
 138     PDB16 *psp = lpPSP;
 139
 140     if(length > 127)
 141     {
 142         WARN( "Command tail truncated! (length %d)\n", length );
 143         length = 126;
 144     }
 145
 146     psp->cmdLine[0] = length;
 147
 148     /*
 149      * Length of exactly 127 bytes means that full command line is
 150      * stored in environment variable CMDLINE and PSP contains
 151      * command tail truncated to 126 bytes.
 152      */
 153     if(length == 127)
 154         length = 126;
 155
 156     if(length > 0)
 157         memmove(psp->cmdLine+1, cmdtail, length);
 158
 159     psp->cmdLine[length+1] = '\r';
 160
 161     /* FIXME: more PSP stuff */
 162 }
 163
 164 static WORD MZ_InitEnvironment( LPCSTR env, LPCSTR name )
 165 {
 166  unsigned sz=0;
 167  unsigned i=0;
 168  WORD seg;
 169  LPSTR envblk;
 170
 171  if (env) {
 172   /* get size of environment block */
 173   while (env[sz++]) sz+=strlen(env+sz)+1;
 174  } else sz++;
 175  /* allocate it */
 176  envblk=DOSMEM_AllocBlock(sz+sizeof(WORD)+strlen(name)+1,&seg);
 177  /* fill it */
 178  if (env) {
 179   memcpy(envblk,env,sz);
 180  } else envblk[0]=0;
 181  /* DOS environment variables are uppercase */
 182  while (envblk[i]){
 183   while (envblk[i] != '='){
 184    if (envblk[i]>='a' && envblk[i] <= 'z'){
 185     envblk[i] -= 32;
 186    }
 187    i++;
 188   }
 189   i += strlen(envblk+i) + 1;
 190  }
 191  /* DOS 3.x: the block contains 1 additional string */
 192  *(WORD*)(envblk+sz)=1;
 193  /* being the program name itself */
 194  strcpy(envblk+sz+sizeof(WORD),name);
 195  return seg;
 196 }
 197
 198 static BOOL MZ_InitMemory(void)
 199 {
 200     /* initialize the memory */
 201     TRACE("Initializing DOS memory structures\n");
 202     DOSMEM_MapDosLayout();
 203     DOSDEV_InstallDOSDevices();
 204     MSCDEX_InstallCDROM();
 205
 206     return TRUE;
 207 }
 208
 209 static BOOL MZ_DoLoadImage( HANDLE hFile, LPCSTR filename, OverlayBlock *oblk, WORD par_env_seg )
 210 {
 211   IMAGE_DOS_HEADER mz_header;
 212   DWORD image_start,image_size,min_size,max_size,avail;
 213   BYTE*psp_start,*load_start;
 214   LPSTR oldenv = 0;
 215   int x, old_com=0, alloc;
 216   SEGPTR reloc;
 217   WORD env_seg, load_seg, rel_seg, oldpsp_seg;
 218   DWORD len;
 219
 220   if (DOSVM_psp) {
 221     /* DOS process already running, inherit from it */
 222     PDB16* par_psp;
 223     alloc=0;
 224     oldpsp_seg = DOSVM_psp;
 225     if( !par_env_seg) {
 226         par_psp = (PDB16*)((DWORD)DOSVM_psp << 4);
 227         oldenv = (LPSTR)((DWORD)par_psp->environment << 4);
 228     }
 229   } else {
 230     /* allocate new DOS process, inheriting from Wine environment */
 231     alloc=1;
 232     oldpsp_seg = 0;
 233     if( !par_env_seg)
 234         oldenv = GetEnvironmentStringsA();
 235   }
 236
 237  SetFilePointer(hFile,0,NULL,FILE_BEGIN);
 238  if (   !ReadFile(hFile,&mz_header,sizeof(mz_header),&len,NULL)
 239      || len != sizeof(mz_header)
 240      || mz_header.e_magic != IMAGE_DOS_SIGNATURE) {
 241   const char *p = strrchr( filename, '.' );
 242   if (!p || strcasecmp( p, ".com" ))  /* check for .COM extension */
 243   {
 244       SetLastError(ERROR_BAD_FORMAT);
 245       goto load_error;
 246   }
 247   old_com=1; /* assume .COM file */
 248   image_start=0;
 249   image_size=GetFileSize(hFile,NULL);
 250   min_size=0x10000; max_size=0x100000;
 251   mz_header.e_crlc=0;
 252   mz_header.e_ss=0; mz_header.e_sp=0xFFFE;
 253   mz_header.e_cs=0; mz_header.e_ip=0x100;
 254  } else {
 255   /* calculate load size */
 256   image_start=mz_header.e_cparhdr<<4;
 257   image_size=mz_header.e_cp<<9; /* pages are 512 bytes */
 258   /* From Ralf Brown Interrupt List: If the word at offset 02h is 4, it should
 259    * be treated as 00h, since pre-1.10 versions of the MS linker set it that
 260    * way. */
 261   if ((mz_header.e_cblp!=0)&&(mz_header.e_cblp!=4)) image_size-=512-mz_header.e_cblp;
 262   image_size-=image_start;
 263   min_size=image_size+((DWORD)mz_header.e_minalloc<<4)+(PSP_SIZE<<4);
 264   max_size=image_size+((DWORD)mz_header.e_maxalloc<<4)+(PSP_SIZE<<4);
 265  }
 266
 267   if (alloc) MZ_InitMemory();
 268
 269   if (oblk) {
 270     /* load overlay into preallocated memory */
 271     load_seg=oblk->load_seg;
 272     rel_seg=oblk->rel_seg;
 273     load_start=(LPBYTE)((DWORD)load_seg<<4);
 274   } else {
 275     /* allocate environment block */
 276     if( par_env_seg)
 277         env_seg = par_env_seg;
 278     else
 279         env_seg=MZ_InitEnvironment(oldenv, filename);
 280     if (alloc)
 281         FreeEnvironmentStringsA( oldenv);
 282
 283     /* allocate memory for the executable */
 284     TRACE("Allocating DOS memory (min=%d, max=%d)\n",min_size,max_size);
 285     avail=DOSMEM_Available();
 286     if (avail<min_size) {
 287       ERR("insufficient DOS memory\n");
 288       SetLastError(ERROR_NOT_ENOUGH_MEMORY);
 289       goto load_error;
 290     }
 291     if (avail>max_size) avail=max_size;
 292     psp_start=DOSMEM_AllocBlock(avail,&DOSVM_psp);
 293     if (!psp_start) {
 294       ERR("error allocating DOS memory\n");
 295       SetLastError(ERROR_NOT_ENOUGH_MEMORY);
 296       goto load_error;
 297     }
 298     load_seg=DOSVM_psp+(old_com?0:PSP_SIZE);
 299     rel_seg=load_seg;
 300     load_start=psp_start+(PSP_SIZE<<4);
 301     MZ_CreatePSP(psp_start, env_seg, oldpsp_seg);
 302   }
 303
 304  /* load executable image */
 305  TRACE("loading DOS %s image, %08x bytes\n",old_com?"COM":"EXE",image_size);
 306  SetFilePointer(hFile,image_start,NULL,FILE_BEGIN);
 307  if (!ReadFile(hFile,load_start,image_size,&len,NULL) || len != image_size) {
 308   /* check if this is due to the workaround for the pre-1.10 MS linker and we
 309      really had only 4 bytes on the last page */
 310   if (mz_header.e_cblp != 4 || image_size - len != 512 - 4) {
 311     SetLastError(ERROR_BAD_FORMAT);
 312     goto load_error;
 313   }
 314  }
 315
 316  if (mz_header.e_crlc) {
 317   /* load relocation table */
 318   TRACE("loading DOS EXE relocation table, %d entries\n",mz_header.e_crlc);
 319   /* FIXME: is this too slow without read buffering? */
 320   SetFilePointer(hFile,mz_header.e_lfarlc,NULL,FILE_BEGIN);
 321   for (x=0; x<mz_header.e_crlc; x++) {
 322    if (!ReadFile(hFile,&reloc,sizeof(reloc),&len,NULL) || len != sizeof(reloc)) {
 323     SetLastError(ERROR_BAD_FORMAT);
 324     goto load_error;
 325    }
 326    *(WORD*)SEGPTR16(load_start,reloc)+=rel_seg;
 327   }
 328  }
 329
 330   if (!oblk) {
 331     init_cs = load_seg+mz_header.e_cs;
 332     init_ip = mz_header.e_ip;
 333     init_ss = load_seg+mz_header.e_ss;
 334     init_sp = mz_header.e_sp;
 335     if (old_com){
 336       /* .COM files exit with ret. Make sure they jump to psp start (=int 20) */
 337       WORD* stack = PTR_REAL_TO_LIN(init_ss, init_sp);
 338       *stack = 0;
 339     }
 340
 341     TRACE("entry point: %04x:%04x\n",init_cs,init_ip);
 342   }
 343
 344   if (alloc && !MZ_InitTask()) {
 345     SetLastError(ERROR_GEN_FAILURE);
 346     return FALSE;
 347   }
 348
 349   return TRUE;
 350
 351 load_error:
 352   DOSVM_psp = oldpsp_seg;
 353
 354   return FALSE;
 355 }
 356
 357 /***********************************************************************
 358  *              __wine_load_dos_exe (KERNEL.@)
 359  *
 360  * Called from WineVDM when a new real-mode DOS process is started.
 361  * Loads DOS program into memory and executes the program.
 362  */
 363 void __wine_load_dos_exe( LPCSTR filename, LPCSTR cmdline )
 364 {
 365     char dos_cmdtail[126];
 366     int  dos_length = 0;
 367
 368     HANDLE hFile = CreateFileA( filename, GENERIC_READ, FILE_SHARE_READ,
 369                                 NULL, OPEN_EXISTING, 0, 0 );
 370     if (hFile == INVALID_HANDLE_VALUE) return;
 371     DOSVM_isdosexe = TRUE;
 372     DOSMEM_InitDosMemory();
 373
 374     if(cmdline && *cmdline)
 375     {
 376         dos_length = strlen(cmdline);
 377         memmove( dos_cmdtail + 1, cmdline,
 378                  (dos_length < 125) ? dos_length : 125 );
 379
 380         /* Non-empty command tail always starts with at least one space. */
 381         dos_cmdtail[0] = ' ';
 382         dos_length++;
 383
 384         /*
 385          * If command tail is longer than 126 characters,
 386          * set tail length to 127 and fill CMDLINE environment variable
 387          * with full command line (this includes filename).
 388          */
 389         if (dos_length > 126)
 390         {
 391             char *cmd = HeapAlloc( GetProcessHeap(), 0,
 392                                    dos_length + strlen(filename) + 4 );
 393             char *ptr = cmd;
 394
 395             if (!cmd)
 396                 return;
 397
 398             /*
 399              * Append filename. If path includes spaces, quote the path.
 400              */
 401             if (strchr(filename, ' '))
 402             {
 403                 *ptr++ = '\"';
 404                 strcpy( ptr, filename );
 405                 ptr += strlen(filename);
 406                 *ptr++ = '\"';
 407             }
 408             else
 409             {
 410                 strcpy( ptr, filename );
 411                 ptr += strlen(filename);
 412             }
 413
 414             /*
 415              * Append command tail.
 416              */
 417             if (cmdline[0] != ' ')
 418                 *ptr++ = ' ';
 419             strcpy( ptr, cmdline );
 420
 421             /*
 422              * Set environment variable. This will be passed to
 423              * new DOS process.
 424              */
 425             if (!SetEnvironmentVariableA( "CMDLINE", cmd ))
 426             {
 427                 HeapFree(GetProcessHeap(), 0, cmd );
 428                 return;
 429             }
 430
 431             HeapFree(GetProcessHeap(), 0, cmd );
 432             dos_length = 127;
 433         }
 434     }
 435
 436     AllocConsole();
 437
 438     if (MZ_DoLoadImage( hFile, filename, NULL, 0 ))
 439     {
 440         DWORD err = MZ_Launch( dos_cmdtail, dos_length );
 441         /* if we get back here it failed */
 442         SetLastError( err );
 443     }
 444 }
 445
 446 /***********************************************************************
 447  *              MZ_Exec
 448  *
 449  * this may only be called from existing DOS processes
 450  */
 451 BOOL MZ_Exec( CONTEXT *context, LPCSTR filename, BYTE func, LPVOID paramblk )
 452 {
 453   DWORD binType;
 454   STARTUPINFOA st;
 455   PROCESS_INFORMATION pe;
 456   HANDLE hFile;
 457
 458   BOOL ret = FALSE;
 459
 460   if(!GetBinaryTypeA(filename, &binType))   /* determine what kind of binary this is */
 461   {
 462     return FALSE; /* binary is not an executable */
 463   }
 464
 465   /* handle non-dos executables */
 466   if(binType != SCS_DOS_BINARY)
 467   {
 468     if(func == 0) /* load and execute */
 469     {
 470       LPSTR fullCmdLine;
 471       WORD fullCmdLength;
 472       LPBYTE psp_start = (LPBYTE)((DWORD)DOSVM_psp << 4);
 473       PDB16 *psp = (PDB16 *)psp_start;
 474       ExecBlock *blk = paramblk;
 475       LPBYTE cmdline = PTR_REAL_TO_LIN(SELECTOROF(blk->cmdline),OFFSETOF(blk->cmdline));
 476       LPBYTE envblock = PTR_REAL_TO_LIN(psp->environment, 0);
 477       int    cmdLength = cmdline[0];
 478
 479       /*
 480        * If cmdLength is 127, command tail is truncated and environment
 481        * variable CMDLINE should contain full command line
 482        * (this includes filename).
 483        */
 484       if (cmdLength == 127)
 485       {
 486           FIXME( "CMDLINE argument passing is unimplemented.\n" );
 487           cmdLength = 126; /* FIXME */
 488       }
 489
 490       fullCmdLength = (strlen(filename) + 1) + cmdLength + 1; /* filename + space + cmdline + terminating null character */
 491
 492       fullCmdLine = HeapAlloc(GetProcessHeap(), 0, fullCmdLength);
 493       if(!fullCmdLine) return FALSE; /* return false on memory alloc failure */
 494
 495       /* build the full command line from the executable file and the command line being passed in */
 496       snprintf(fullCmdLine, fullCmdLength, "%s ", filename); /* start off with the executable filename and a space */
 497       memcpy(fullCmdLine + strlen(fullCmdLine), cmdline + 1, cmdLength); /* append cmdline onto the end */
 498       fullCmdLine[fullCmdLength - 1] = 0; /* null terminate string */
 499
 500       ZeroMemory (&st, sizeof(STARTUPINFOA));
 501       st.cb = sizeof(STARTUPINFOA);
 502       ret = CreateProcessA (NULL, fullCmdLine, NULL, NULL, TRUE, 0, envblock, NULL, &st, &pe);
 503
 504       /* wait for the app to finish and clean up PROCESS_INFORMATION handles */
 505       if(ret)
 506       {
 507         WaitForSingleObject(pe.hProcess, INFINITE);  /* wait here until the child process is complete */
 508         CloseHandle(pe.hProcess);
 509         CloseHandle(pe.hThread);
 510       }
 511
 512       HeapFree(GetProcessHeap(), 0, fullCmdLine);  /* free the memory we allocated */
 513     }
 514     else
 515     {
 516       FIXME("EXEC type of %d not implemented for non-dos executables\n", func);
 517       ret = FALSE;
 518     }
 519
 520     return ret;
 521   } /* if(binType != SCS_DOS_BINARY) */
 522
 523
 524   /* handle dos executables */
 525
 526   hFile = CreateFileA( filename, GENERIC_READ, FILE_SHARE_READ,
 527                              NULL, OPEN_EXISTING, 0, 0);
 528   if (hFile == INVALID_HANDLE_VALUE) return FALSE;
 529
 530   switch (func) {
 531   case 0: /* load and execute */
 532   case 1: /* load but don't execute */
 533     {
 534       /* save current process's return SS:SP now */
 535       LPBYTE psp_start = (LPBYTE)((DWORD)DOSVM_psp << 4);
 536       PDB16 *psp = (PDB16 *)psp_start;
 537       psp->saveStack = (DWORD)MAKESEGPTR(context->SegSs, LOWORD(context->Esp));
 538     }
 539     ret = MZ_DoLoadImage( hFile, filename, NULL, ((ExecBlock *)paramblk)->env_seg );
 540     if (ret) {
 541       /* MZ_LoadImage created a new PSP and loaded new values into it,
 542        * let's work on the new values now */
 543       LPBYTE psp_start = (LPBYTE)((DWORD)DOSVM_psp << 4);
 544       ExecBlock *blk = paramblk;
 545       LPBYTE cmdline = PTR_REAL_TO_LIN(SELECTOROF(blk->cmdline),OFFSETOF(blk->cmdline));
 546
 547       /* First character contains the length of the command line. */
 548       MZ_FillPSP(psp_start, (LPSTR)cmdline + 1, cmdline[0]);
 549
 550       /* the lame MS-DOS engineers decided that the return address should be in int22 */
 551       DOSVM_SetRMHandler(0x22, (FARPROC16)MAKESEGPTR(context->SegCs, LOWORD(context->Eip)));
 552       if (func) {
 553         /* don't execute, just return startup state */
 554         /*
 555          * From Ralph Brown:
 556          *  For function 01h, the AX value to be passed to the child program
 557          *  is put on top of the child's stack
 558          */
 559         LPBYTE stack;
 560         init_sp -= 2;
 561         stack = CTX_SEG_OFF_TO_LIN(context, init_ss, init_sp);
 562         /* FIXME: push AX correctly */
 563         stack[0] = 0x00;    /* push AL */
 564         stack[1] = 0x00;    /* push AH */
 565
 566         blk->init_cs = init_cs;
 567         blk->init_ip = init_ip;
 568         blk->init_ss = init_ss;
 569         blk->init_sp = init_sp;
 570       } else {
 571         /* execute by making us return to new process */
 572         context->SegCs = init_cs;
 573         context->Eip   = init_ip;
 574         context->SegSs = init_ss;
 575         context->Esp   = init_sp;
 576         context->SegDs = DOSVM_psp;
 577         context->SegEs = DOSVM_psp;
 578         context->Eax   = 0;
 579       }
 580     }
 581     break;
 582   case 3: /* load overlay */
 583     {
 584       OverlayBlock *blk = paramblk;
 585       ret = MZ_DoLoadImage( hFile, filename, blk, 0);
 586     }
 587     break;
 588   default:
 589     FIXME("EXEC load type %d not implemented\n", func);
 590     SetLastError(ERROR_INVALID_FUNCTION);
 591     break;
 592   }
 593   CloseHandle(hFile);
 594   return ret;
 595 }
 596
 597 /***********************************************************************
 598  *              MZ_AllocDPMITask
 599  */
 600 void MZ_AllocDPMITask( void )
 601 {
 602   MZ_InitMemory();
 603   MZ_InitTask();
 604 }
 605
 606 /***********************************************************************
 607  *              MZ_RunInThread
 608  */
 609 void MZ_RunInThread( PAPCFUNC proc, ULONG_PTR arg )
 610 {
 611   if (loop_thread) {
 612     DOS_SPC spc;
 613     HANDLE event;
 614
 615     spc.proc = proc;
 616     spc.arg = arg;
 617     event = CreateEventW(NULL, TRUE, FALSE, NULL);
 618     PostThreadMessageA(loop_tid, WM_USER, (WPARAM)event, (LPARAM)&spc);
 619     WaitForSingleObject(event, INFINITE);
 620     CloseHandle(event);
 621   } else
 622     proc(arg);
 623 }
 624
 625 static DWORD WINAPI MZ_DOSVM( LPVOID lpExtra )
 626 {
 627   CONTEXT context;
 628   INT ret;
 629
 630   dosvm_pid = getpid();
 631
 632   memset( &context, 0, sizeof(context) );
 633   context.SegCs  = init_cs;
 634   context.Eip    = init_ip;
 635   context.SegSs  = init_ss;
 636   context.Esp    = init_sp;
 637   context.SegDs  = DOSVM_psp;
 638   context.SegEs  = DOSVM_psp;
 639   context.EFlags = V86_FLAG | VIF_MASK;
 640   DOSVM_SetTimer(0x10000);
 641   ret = DOSVM_Enter( &context );
 642   if (ret == -1) ret = GetLastError();
 643   dosvm_pid = 0;
 644   return ret;
 645 }
 646
 647 static BOOL MZ_InitTask(void)
 648 {
 649   if (!DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
 650                        GetCurrentProcess(), &loop_thread,
 651                        0, FALSE, DUPLICATE_SAME_ACCESS))
 652     return FALSE;
 653   dosvm_thread = CreateThread(NULL, 0, MZ_DOSVM, NULL, CREATE_SUSPENDED, &dosvm_tid);
 654   if (!dosvm_thread) {
 655     CloseHandle(loop_thread);
 656     loop_thread = 0;
 657     return FALSE;
 658   }
 659   loop_tid = GetCurrentThreadId();
 660   return TRUE;
 661 }
 662
 663 static DWORD MZ_Launch( LPCSTR cmdtail, int length )
 664 {
 665   TDB *pTask = GlobalLock16( GetCurrentTask() );
 666   BYTE *psp_start = PTR_REAL_TO_LIN( DOSVM_psp, 0 );
 667   DWORD rv;
 668   SYSLEVEL *lock;
 669   MSG msg;
 670
 671   MZ_FillPSP(psp_start, cmdtail, length);
 672   pTask->flags |= TDBF_WINOLDAP;
 673
 674   /* DTA is set to PSP:0080h when a program is started. */
 675   pTask->dta = MAKESEGPTR( DOSVM_psp, 0x80 );
 676
 677   GetpWin16Lock( &lock );
 678   _LeaveSysLevel( lock );
 679
 680   /* force the message queue to be created */
 681   PeekMessageW(&msg, NULL, WM_USER, WM_USER, PM_NOREMOVE);
 682
 683   ResumeThread(dosvm_thread);
 684   rv = DOSVM_Loop(dosvm_thread);
 685
 686   CloseHandle(dosvm_thread);
 687   dosvm_thread = 0; dosvm_tid = 0;
 688   CloseHandle(loop_thread);
 689   loop_thread = 0; loop_tid = 0;
 690   if (rv) return rv;
 691
 692   VGA_Clean();
 693   ExitProcess(0);
 694 }
 695
 696 /***********************************************************************
 697  *              MZ_Exit
 698  */
 699 void MZ_Exit( CONTEXT *context, BOOL cs_psp, WORD retval )
 700 {
 701   if (DOSVM_psp) {
 702     WORD psp_seg = cs_psp ? context->SegCs : DOSVM_psp;
 703     LPBYTE psp_start = (LPBYTE)((DWORD)psp_seg << 4);
 704     PDB16 *psp = (PDB16 *)psp_start;
 705     WORD parpsp = psp->parentPSP; /* check for parent DOS process */
 706     if (parpsp) {
 707       /* retrieve parent's return address */
 708       FARPROC16 retaddr = DOSVM_GetRMHandler(0x22);
 709       /* restore interrupts */
 710       DOSVM_SetRMHandler(0x22, psp->savedint22);
 711       DOSVM_SetRMHandler(0x23, psp->savedint23);
 712       DOSVM_SetRMHandler(0x24, psp->savedint24);
 713       /* FIXME: deallocate file handles etc */
 714       /* free process's associated memory
 715        * FIXME: walk memory and deallocate all blocks owned by process */
 716       DOSMEM_FreeBlock( PTR_REAL_TO_LIN(psp->environment,0) );
 717       DOSMEM_FreeBlock( PTR_REAL_TO_LIN(DOSVM_psp,0) );
 718       /* switch to parent's PSP */
 719       DOSVM_psp = parpsp;
 720       psp_start = (LPBYTE)((DWORD)parpsp << 4);
 721       psp = (PDB16 *)psp_start;
 722       /* now return to parent */
 723       DOSVM_retval = retval;
 724       context->SegCs = SELECTOROF(retaddr);
 725       context->Eip   = OFFSETOF(retaddr);
 726       context->SegSs = SELECTOROF(psp->saveStack);
 727       context->Esp   = OFFSETOF(psp->saveStack);
 728       return;
 729     } else
 730       TRACE("killing DOS task\n");
 731   }
 732   DOSVM_Exit( retval );
 733 }
 734
 735
 736 /***********************************************************************
 737  *              MZ_Current
 738  */
 739 BOOL MZ_Current( void )
 740 {
 741   return (dosvm_pid != 0); /* FIXME: do a better check */
 742 }
 743
 744 #else /* !MZ_SUPPORTED */
 745
 746 /***********************************************************************
 747  *              __wine_load_dos_exe (KERNEL.@)
 748  */
 749 void __wine_load_dos_exe( LPCSTR filename, LPCSTR cmdline )
 750 {
 751     SetLastError( ERROR_NOT_SUPPORTED );
 752 }
 753
 754 /***********************************************************************
 755  *              MZ_Exec
 756  */
 757 BOOL MZ_Exec( CONTEXT *context, LPCSTR filename, BYTE func, LPVOID paramblk )
 758 {
 759   /* can't happen */
 760   SetLastError(ERROR_BAD_FORMAT);
 761   return FALSE;
 762 }
 763
 764 /***********************************************************************
 765  *              MZ_AllocDPMITask
 766  */
 767 void MZ_AllocDPMITask( void )
 768 {
 769     FIXME("Actual real-mode calls not supported on this platform!\n");
 770 }
 771
 772 /***********************************************************************
 773  *              MZ_RunInThread
 774  */
 775 void MZ_RunInThread( PAPCFUNC proc, ULONG_PTR arg )
 776 {
 777     proc(arg);
 778 }
 779
 780 /***********************************************************************
 781  *              MZ_Exit
 782  */
 783 void MZ_Exit( CONTEXT *context, BOOL cs_psp, WORD retval )
 784 {
 785   DOSVM_Exit( retval );
 786 }
 787
 788 /***********************************************************************
 789  *              MZ_Current
 790  */
 791 BOOL MZ_Current( void )
 792 {
 793     return FALSE;
 794 }
 795
 796 #endif /* !MZ_SUPPORTED */