loader/dos/dosvm.c

   1 /*
   2  * DOS Virtual Machine
   3  *
   4  * Copyright 1998 Ove Kåven
   5  *
   6  * This code hasn't been completely cleaned up yet.
   7  */
   8
   9 #include "config.h"
  10
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14 #include <errno.h>
  15 #include <fcntl.h>
  16 #include <signal.h>
  17 #include <unistd.h>
  18 #include <sys/time.h>
  19 #include <sys/types.h>
  20 #include <sys/stat.h>
  21
  22 #include "wine/winbase16.h"
  23 #include "wine/exception.h"
  24 #include "windef.h"
  25 #include "wingdi.h"
  26 #include "winuser.h"
  27 #include "winnt.h"
  28
  29 #include "callback.h"
  30 #include "msdos.h"
  31 #include "file.h"
  32 #include "miscemu.h"
  33 #include "dosexe.h"
  34 #include "dosmod.h"
  35 #include "stackframe.h"
  36 #include "debugtools.h"
  37
  38 DECLARE_DEBUG_CHANNEL(int)
  39 DECLARE_DEBUG_CHANNEL(module)
  40 DECLARE_DEBUG_CHANNEL(relay)
  41
  42 #ifdef MZ_SUPPORTED
  43
  44 #ifdef HAVE_SYS_VM86_H
  45 # include <sys/vm86.h>
  46 #endif
  47 #ifdef HAVE_SYS_MMAN_H
  48 # include <sys/mman.h>
  49 #endif
  50
  51 #define IF_CLR(ctx) EFL_reg(ctx) &= ~VIF_MASK
  52 #define IF_ENABLED(ctx) (EFL_reg(ctx) & VIF_MASK)
  53 #define SET_PEND(ctx) EFL_reg(ctx) |= VIP_MASK
  54 #define CLR_PEND(ctx) EFL_reg(ctx) &= ~VIP_MASK
  55 #define IS_PEND(ctx) (EFL_reg(ctx) & VIP_MASK)
  56
  57 #undef TRY_PICRETURN
  58
  59 static void do_exception( int signal, CONTEXT86 *context )
  60 {
  61     EXCEPTION_RECORD rec;
  62     if ((signal == SIGTRAP) || (signal == SIGHUP))
  63     {
  64         rec.ExceptionCode  = EXCEPTION_BREAKPOINT;
  65         rec.ExceptionFlags = EXCEPTION_CONTINUABLE;
  66     }
  67     else
  68     {
  69         rec.ExceptionCode  = EXCEPTION_ILLEGAL_INSTRUCTION;  /* generic error */
  70         rec.ExceptionFlags = EH_NONCONTINUABLE;
  71     }
  72     rec.ExceptionRecord  = NULL;
  73     rec.ExceptionAddress = (LPVOID)EIP_reg(context);
  74     rec.NumberParameters = 0;
  75     EXC_RtlRaiseException( &rec, context );
  76 }
  77
  78 static void DOSVM_Dump( LPDOSTASK lpDosTask, int fn, int sig,
  79                         struct vm86plus_struct*VM86 )
  80 {
  81  unsigned iofs;
  82  BYTE*inst;
  83  int x;
  84
  85  switch (VM86_TYPE(fn)) {
  86   case VM86_SIGNAL:
  87    printf("Trapped signal %d\n",sig); break;
  88   case VM86_UNKNOWN:
  89    printf("Trapped unhandled GPF\n"); break;
  90   case VM86_INTx:
  91    printf("Trapped INT %02x\n",VM86_ARG(fn)); break;
  92   case VM86_STI:
  93    printf("Trapped STI\n"); break;
  94   case VM86_PICRETURN:
  95    printf("Trapped due to pending PIC request\n"); break;
  96   case VM86_TRAP:
  97    printf("Trapped debug request\n"); break;
  98   default:
  99    printf("Trapped unknown VM86 type %d arg %d\n",VM86_TYPE(fn),VM86_ARG(fn)); break;
 100  }
 101 #define REGS VM86->regs
 102  fprintf(stderr,"AX=%04lX CX=%04lX DX=%04lX BX=%04lX\n",REGS.eax,REGS.ecx,REGS.edx,REGS.ebx);
 103  fprintf(stderr,"SI=%04lX DI=%04lX SP=%04lX BP=%04lX\n",REGS.esi,REGS.edi,REGS.esp,REGS.ebp);
 104  fprintf(stderr,"CS=%04X DS=%04X ES=%04X SS=%04X\n",REGS.cs,REGS.ds,REGS.es,REGS.ss);
 105  fprintf(stderr,"IP=%04lX EFLAGS=%08lX\n",REGS.eip,REGS.eflags);
 106
 107  iofs=((DWORD)REGS.cs<<4)+REGS.eip;
 108 #undef REGS
 109  inst=(BYTE*)lpDosTask->img+iofs;
 110  printf("Opcodes:");
 111  for (x=0; x<8; x++) printf(" %02x",inst[x]);
 112  printf("\n");
 113 }
 114
 115 static int DOSVM_Int( int vect, CONTEXT86 *context, LPDOSTASK lpDosTask )
 116 {
 117  extern UINT16 DPMI_wrap_seg;
 118
 119  if (vect==0x31) {
 120   if (CS_reg(context)==DPMI_wrap_seg) {
 121    /* exit from real-mode wrapper */
 122    return -1;
 123   }
 124   /* we could probably move some other dodgy stuff here too from dpmi.c */
 125  }
 126  INT_RealModeInterrupt(vect,context);
 127  return 0;
 128 }
 129
 130 static void DOSVM_SimulateInt( int vect, CONTEXT86 *context, LPDOSTASK lpDosTask )
 131 {
 132   FARPROC16 handler=INT_GetRMHandler(vect);
 133
 134   if (SELECTOROF(handler)==0xf000) {
 135     /* if internal interrupt, call it directly */
 136     INT_RealModeInterrupt(vect,context);
 137   } else {
 138     WORD*stack=(WORD*)(V86BASE(context)+(((DWORD)SS_reg(context))<<4)+LOWORD(ESP_reg(context)));
 139     WORD flag=LOWORD(EFL_reg(context));
 140
 141     if (IF_ENABLED(context)) flag|=IF_MASK;
 142     else flag&=~IF_MASK;
 143
 144     *(--stack)=flag;
 145     *(--stack)=CS_reg(context);
 146     *(--stack)=LOWORD(EIP_reg(context));
 147     ESP_reg(context)-=6;
 148     CS_reg(context)=SELECTOROF(handler);
 149     EIP_reg(context)=OFFSETOF(handler);
 150     IF_CLR(context);
 151   }
 152 }
 153
 154 #define SHOULD_PEND(x) \
 155   (x && ((!lpDosTask->current) || (x->priority < lpDosTask->current->priority)))
 156
 157 static void DOSVM_SendQueuedEvent(CONTEXT86 *context, LPDOSTASK lpDosTask)
 158 {
 159   LPDOSEVENT event = lpDosTask->pending;
 160
 161   if (SHOULD_PEND(event)) {
 162     /* remove from "pending" list */
 163     lpDosTask->pending = event->next;
 164     /* process event */
 165     if (event->irq>=0) {
 166       /* it's an IRQ, move it to "current" list */
 167       event->next = lpDosTask->current;
 168       lpDosTask->current = event;
 169       TRACE_(int)("dispatching IRQ %d\n",event->irq);
 170       /* note that if DOSVM_SimulateInt calls an internal interrupt directly,
 171        * lpDosTask->current might be cleared (and event freed) in this very call! */
 172       DOSVM_SimulateInt((event->irq<8)?(event->irq+8):(event->irq-8+0x70),context,lpDosTask);
 173     } else {
 174       /* callback event */
 175       TRACE_(int)("dispatching callback event\n");
 176       (*event->relay)(lpDosTask,context,event->data);
 177       free(event);
 178     }
 179   }
 180   if (!SHOULD_PEND(lpDosTask->pending)) {
 181     TRACE_(int)("clearing Pending flag\n");
 182     CLR_PEND(context);
 183   }
 184 }
 185
 186 static void DOSVM_SendQueuedEvents(CONTEXT86 *context, LPDOSTASK lpDosTask)
 187 {
 188   /* we will send all queued events as long as interrupts are enabled,
 189    * but IRQ events will disable interrupts again */
 190   while (IS_PEND(context) && IF_ENABLED(context))
 191     DOSVM_SendQueuedEvent(context,lpDosTask);
 192 }
 193
 194 void DOSVM_QueueEvent( int irq, int priority, void (*relay)(LPDOSTASK,CONTEXT86*,void*), void *data)
 195 {
 196   LPDOSTASK lpDosTask = MZ_Current();
 197   LPDOSEVENT event, cur, prev;
 198
 199   if (lpDosTask) {
 200     event = malloc(sizeof(DOSEVENT));
 201     if (!event) {
 202       ERR_(int)("out of memory allocating event entry\n");
 203       return;
 204     }
 205     event->irq = irq; event->priority = priority;
 206     event->relay = relay; event->data = data;
 207
 208     /* insert event into linked list, in order *after*
 209      * all earlier events of higher or equal priority */
 210     cur = lpDosTask->pending; prev = NULL;
 211     while (cur && cur->priority<=priority) {
 212       prev = cur;
 213       cur = cur->next;
 214     }
 215     event->next = cur;
 216     if (prev) prev->next = event;
 217     else lpDosTask->pending = event;
 218
 219     /* get dosmod's attention to the new event, except for irq==0 where we already have it */
 220     if (irq && !lpDosTask->sig_sent) {
 221       TRACE_(int)("new event queued, signalling dosmod\n");
 222       kill(lpDosTask->task,SIGUSR2);
 223       lpDosTask->sig_sent++;
 224     } else {
 225       TRACE_(int)("new event queued\n");
 226     }
 227   }
 228 }
 229
 230 #define CV CP(eax,EAX); CP(ecx,ECX); CP(edx,EDX); CP(ebx,EBX); \
 231            CP(esi,ESI); CP(edi,EDI); CP(esp,ESP); CP(ebp,EBP); \
 232            CP(cs,CS); CP(ds,DS); CP(es,ES); \
 233            CP(ss,SS); CP(fs,FS); CP(gs,GS); \
 234            CP(eip,EIP); CP(eflags,EFL)
 235
 236 static int DOSVM_Process( LPDOSTASK lpDosTask, int fn, int sig,
 237                           struct vm86plus_struct*VM86 )
 238 {
 239  CONTEXT86 context;
 240  int ret=0;
 241
 242 #define CP(x,y) y##_reg(&context) = VM86->regs.x
 243   CV;
 244 #undef CP
 245  if (VM86_TYPE(fn)==VM86_UNKNOWN) {
 246   ret=INSTR_EmulateInstruction(&context);
 247 #define CP(x,y) VM86->regs.x = y##_reg(&context)
 248   CV;
 249 #undef CP
 250   if (ret) return 0;
 251   ret=0;
 252  }
 253  (void*)V86BASE(&context)=lpDosTask->img;
 254 #ifdef TRY_PICRETURN
 255  if (VM86->vm86plus.force_return_for_pic) {
 256    SET_PEND(&context);
 257  }
 258 #else
 259  /* linux doesn't preserve pending flag on return */
 260  if (SHOULD_PEND(lpDosTask->pending)) {
 261    SET_PEND(&context);
 262  }
 263 #endif
 264
 265  switch (VM86_TYPE(fn)) {
 266   case VM86_SIGNAL:
 267    TRACE_(int)("DOS module caught signal %d\n",sig);
 268    if ((sig==SIGALRM) || (sig==SIGUSR2)) {
 269      if (sig==SIGALRM) {
 270        DOSVM_QueueEvent(0,DOS_PRIORITY_REALTIME,NULL,NULL);
 271      }
 272      if (lpDosTask->pending) {
 273        TRACE_(int)("setting Pending flag, interrupts are currently %s\n",
 274                  IF_ENABLED(&context) ? "enabled" : "disabled");
 275        SET_PEND(&context);
 276        DOSVM_SendQueuedEvents(&context,lpDosTask);
 277      } else {
 278        TRACE_(int)("no events are pending, clearing Pending flag\n");
 279        CLR_PEND(&context);
 280      }
 281      if (sig==SIGUSR2) lpDosTask->sig_sent--;
 282    }
 283    else if ((sig==SIGHUP) || (sig==SIGILL) || (sig==SIGSEGV)) {
 284        do_exception( sig, &context );
 285    } else {
 286     DOSVM_Dump(lpDosTask,fn,sig,VM86);
 287     ret=-1;
 288    }
 289    break;
 290   case VM86_UNKNOWN: /* unhandled GPF */
 291    DOSVM_Dump(lpDosTask,fn,sig,VM86);
 292    do_exception( SIGSEGV, &context );
 293    break;
 294   case VM86_INTx:
 295    if (TRACE_ON(relay))
 296     DPRINTF("Call DOS int 0x%02x (EAX=%08lx) ret=%04lx:%04lx\n",VM86_ARG(fn),context.Eax,context.SegCs,context.Eip);
 297    ret=DOSVM_Int(VM86_ARG(fn),&context,lpDosTask);
 298    if (TRACE_ON(relay))
 299     DPRINTF("Ret  DOS int 0x%02x (EAX=%08lx) ret=%04lx:%04lx\n",VM86_ARG(fn),context.Eax,context.SegCs,context.Eip);
 300    break;
 301   case VM86_STI:
 302   case VM86_PICRETURN:
 303     TRACE_(int)("DOS task enabled interrupts with events pending, sending events\n");
 304     DOSVM_SendQueuedEvents(&context,lpDosTask);
 305     break;
 306   case VM86_TRAP:
 307    do_exception( SIGTRAP, &context );
 308    break;
 309   default:
 310    DOSVM_Dump(lpDosTask,fn,sig,VM86);
 311    ret=-1;
 312  }
 313
 314 #define CP(x,y) VM86->regs.x = y##_reg(&context)
 315  CV;
 316 #undef CP
 317 #ifdef TRY_PICRETURN
 318  VM86->vm86plus.force_return_for_pic = IS_PEND(&context) ? 1 : 0;
 319  CLR_PEND(&context);
 320 #endif
 321  return ret;
 322 }
 323
 324 void DOSVM_ProcessMessage(LPDOSTASK lpDosTask,MSG *msg)
 325 {
 326   BYTE scan = 0;
 327
 328   fprintf(stderr,"got message %04x, wparam=%08x, lparam=%08lx\n",msg->message,msg->wParam,msg->lParam);
 329   if ((msg->message>=WM_MOUSEFIRST)&&
 330       (msg->message<=WM_MOUSELAST)) {
 331     INT_Int33Message(msg->message,msg->wParam,msg->lParam);
 332   } else {
 333     switch (msg->message) {
 334     case WM_KEYUP:
 335       scan = 0x80;
 336     case WM_KEYDOWN:
 337       scan |= (msg->lParam >> 16) & 0x7f;
 338
 339       /* check whether extended bit is set,
 340        * and if so, queue the extension prefix */
 341       if (msg->lParam & 0x1000000) {
 342         /* FIXME: some keys (function keys) have
 343          * extended bit set even when they shouldn't,
 344          * should check for them */
 345         INT_Int09SendScan(0xE0);
 346       }
 347       INT_Int09SendScan(scan);
 348       break;
 349     }
 350   }
 351 }
 352
 353 void DOSVM_Wait( int read_pipe, HANDLE hObject )
 354 {
 355   LPDOSTASK lpDosTask = MZ_Current();
 356   MSG msg;
 357   DWORD waitret;
 358   BOOL got_msg = FALSE;
 359
 360   do {
 361     /* check for messages (waste time before the response check below) */
 362     while (Callout.PeekMessageA(&msg,0,0,0,PM_REMOVE|PM_NOYIELD)) {
 363       /* got a message */
 364       DOSVM_ProcessMessage(lpDosTask,&msg);
 365       /* we don't need a TranslateMessage here */
 366       Callout.DispatchMessageA(&msg);
 367       got_msg = TRUE;
 368     }
 369     if (read_pipe == -1) {
 370       if (got_msg) break;
 371     } else {
 372       fd_set readfds;
 373       struct timeval timeout={0,0};
 374       /* quick check for response from dosmod
 375        * (faster than doing the full blocking wait, if data already available) */
 376       FD_ZERO(&readfds); FD_SET(read_pipe,&readfds);
 377       if (select(read_pipe+1,&readfds,NULL,NULL,&timeout)>0)
 378         break;
 379     }
 380     /* check for data from win32 console device */
 381
 382     /* nothing yet, block while waiting for something to do */
 383     waitret=MsgWaitForMultipleObjects(1,&hObject,FALSE,INFINITE,QS_ALLINPUT);
 384     if (waitret==(DWORD)-1) {
 385       ERR_(module)("dosvm wait error=%ld\n",GetLastError());
 386     }
 387     if (read_pipe != -1) {
 388       if (waitret==WAIT_OBJECT_0) break;
 389     }
 390   } while (TRUE);
 391 }
 392
 393 int DOSVM_Enter( CONTEXT86 *context )
 394 {
 395  LPDOSTASK lpDosTask = MZ_Current();
 396  struct vm86plus_struct VM86;
 397  int stat,len,sig;
 398
 399  if (!lpDosTask) {
 400   /* MZ_CreateProcess or MZ_AllocDPMITask should have been called first */
 401   ERR_(module)("dosmod has not been initialized!");
 402   return -1;
 403  }
 404
 405  if (context) {
 406 #define CP(x,y) VM86.regs.x = y##_reg(context)
 407   CV;
 408 #undef CP
 409   if (VM86.regs.eflags & IF_MASK)
 410     VM86.regs.eflags |= VIF_MASK;
 411  } else {
 412 /* initial setup */
 413   /* allocate standard DOS handles */
 414   FILE_InitProcessDosHandles();
 415   /* registers */
 416   memset(&VM86,0,sizeof(VM86));
 417   VM86.regs.cs=lpDosTask->init_cs;
 418   VM86.regs.eip=lpDosTask->init_ip;
 419   VM86.regs.ss=lpDosTask->init_ss;
 420   VM86.regs.esp=lpDosTask->init_sp;
 421   VM86.regs.ds=lpDosTask->psp_seg;
 422   VM86.regs.es=lpDosTask->psp_seg;
 423   VM86.regs.eflags=VIF_MASK;
 424   /* hmm, what else do we need? */
 425  }
 426
 427  /* main exchange loop */
 428  do {
 429   stat = VM86_ENTER;
 430   errno = 0;
 431   /* transmit VM86 structure to dosmod task */
 432   if (write(lpDosTask->write_pipe,&stat,sizeof(stat))!=sizeof(stat)) {
 433    ERR_(module)("dosmod sync lost, errno=%d, fd=%d, pid=%d\n",errno,lpDosTask->write_pipe,getpid());
 434    return -1;
 435   }
 436   if (write(lpDosTask->write_pipe,&VM86,sizeof(VM86))!=sizeof(VM86)) {
 437    ERR_(module)("dosmod sync lost, errno=%d\n",errno);
 438    return -1;
 439   }
 440   /* wait for response, doing other things in the meantime */
 441   DOSVM_Wait(lpDosTask->read_pipe, lpDosTask->hReadPipe);
 442   /* read response */
 443   while (1) {
 444     if ((len=read(lpDosTask->read_pipe,&stat,sizeof(stat)))==sizeof(stat)) break;
 445     if (((errno==EINTR)||(errno==EAGAIN))&&(len<=0)) {
 446      WARN_(module)("rereading dosmod return code due to errno=%d, result=%d\n",errno,len);
 447      continue;
 448     }
 449     ERR_(module)("dosmod sync lost reading return code, errno=%d, result=%d\n",errno,len);
 450     return -1;
 451   }
 452   TRACE_(module)("dosmod return code=%d\n",stat);
 453   while (1) {
 454     if ((len=read(lpDosTask->read_pipe,&VM86,sizeof(VM86)))==sizeof(VM86)) break;
 455     if (((errno==EINTR)||(errno==EAGAIN))&&(len<=0)) {
 456      WARN_(module)("rereading dosmod VM86 structure due to errno=%d, result=%d\n",errno,len);
 457      continue;
 458     }
 459     ERR_(module)("dosmod sync lost reading VM86 structure, errno=%d, result=%d\n",errno,len);
 460     return -1;
 461   }
 462   if ((stat&0xff)==DOSMOD_SIGNAL) {
 463     while (1) {
 464       if ((len=read(lpDosTask->read_pipe,&sig,sizeof(sig)))==sizeof(sig)) break;
 465       if (((errno==EINTR)||(errno==EAGAIN))&&(len<=0)) {
 466         WARN_(module)("rereading dosmod signal due to errno=%d, result=%d\n",errno,len);
 467         continue;
 468       }
 469       ERR_(module)("dosmod sync lost reading signal, errno=%d, result=%d\n",errno,len);
 470       return -1;
 471     } while (0);
 472   } else sig=0;
 473   /* got response */
 474  } while (DOSVM_Process(lpDosTask,stat,sig,&VM86)>=0);
 475
 476  if (context) {
 477 #define CP(x,y) y##_reg(context) = VM86.regs.x
 478   CV;
 479 #undef CP
 480  }
 481  return 0;
 482 }
 483
 484 void DOSVM_PIC_ioport_out( WORD port, BYTE val)
 485 {
 486   LPDOSTASK lpDosTask = MZ_Current();
 487   LPDOSEVENT event;
 488
 489   if (lpDosTask) {
 490     if ((port==0x20) && (val==0x20)) {
 491       if (lpDosTask->current) {
 492         /* EOI (End Of Interrupt) */
 493         TRACE_(int)("received EOI for current IRQ, clearing\n");
 494         event = lpDosTask->current;
 495         lpDosTask->current = event->next;
 496         if (event->relay)
 497         (*event->relay)(lpDosTask,NULL,event->data);
 498         free(event);
 499
 500         if (lpDosTask->pending &&
 501             !lpDosTask->sig_sent) {
 502           /* another event is pending, which we should probably
 503            * be able to process now, so tell dosmod about it */
 504           TRACE_(int)("another event pending, signalling dosmod\n");
 505           kill(lpDosTask->task,SIGUSR2);
 506           lpDosTask->sig_sent++;
 507         }
 508       } else {
 509         WARN_(int)("EOI without active IRQ\n");
 510       }
 511     } else {
 512       FIXME_(int)("unrecognized PIC command %02x\n",val);
 513     }
 514   }
 515 }
 516
 517 void DOSVM_SetTimer( unsigned ticks )
 518 {
 519   LPDOSTASK lpDosTask = MZ_Current();
 520   int stat=DOSMOD_SET_TIMER;
 521   struct timeval tim;
 522
 523   if (lpDosTask) {
 524     /* the PC clocks ticks at 1193180 Hz */
 525     tim.tv_sec=0;
 526     tim.tv_usec=((unsigned long long)ticks*1000000)/1193180;
 527     /* sanity check */
 528     if (!tim.tv_usec) tim.tv_usec=1;
 529
 530     if (write(lpDosTask->write_pipe,&stat,sizeof(stat))!=sizeof(stat)) {
 531       ERR_(module)("dosmod sync lost, errno=%d\n",errno);
 532       return;
 533     }
 534     if (write(lpDosTask->write_pipe,&tim,sizeof(tim))!=sizeof(tim)) {
 535       ERR_(module)("dosmod sync lost, errno=%d\n",errno);
 536       return;
 537     }
 538     /* there's no return */
 539   }
 540 }
 541
 542 unsigned DOSVM_GetTimer( void )
 543 {
 544   LPDOSTASK lpDosTask = MZ_Current();
 545   int stat=DOSMOD_GET_TIMER;
 546   struct timeval tim;
 547
 548   if (lpDosTask) {
 549     if (write(lpDosTask->write_pipe,&stat,sizeof(stat))!=sizeof(stat)) {
 550       ERR_(module)("dosmod sync lost, errno=%d\n",errno);
 551       return 0;
 552     }
 553     /* read response */
 554     while (1) {
 555       if (read(lpDosTask->read_pipe,&tim,sizeof(tim))==sizeof(tim)) break;
 556       if ((errno==EINTR)||(errno==EAGAIN)) continue;
 557       ERR_(module)("dosmod sync lost, errno=%d\n",errno);
 558       return 0;
 559     }
 560     return ((unsigned long long)tim.tv_usec*1193180)/1000000;
 561   }
 562   return 0;
 563 }
 564
 565 void DOSVM_SetSystemData( int id, void *data )
 566 {
 567   LPDOSTASK lpDosTask = MZ_Current();
 568   DOSSYSTEM *sys, *prev;
 569
 570   if (lpDosTask) {
 571     sys = lpDosTask->sys;
 572     prev = NULL;
 573     while (sys && (sys->id != id)) {
 574       prev = sys;
 575       sys = sys->next;
 576     }
 577     if (sys) {
 578       free(sys->data);
 579       sys->data = data;
 580     } else {
 581       sys = malloc(sizeof(DOSSYSTEM));
 582       sys->id = id;
 583       sys->data = data;
 584       sys->next = NULL;
 585       if (prev) prev->next = sys;
 586       else lpDosTask->sys = sys;
 587     }
 588   } else free(data);
 589 }
 590
 591 void* DOSVM_GetSystemData( int id )
 592 {
 593   LPDOSTASK lpDosTask = MZ_Current();
 594   DOSSYSTEM *sys;
 595
 596   if (lpDosTask) {
 597     sys = lpDosTask->sys;
 598     while (sys && (sys->id != id))
 599       sys = sys->next;
 600     if (sys)
 601       return sys->data;
 602   }
 603   return NULL;
 604 }
 605
 606 #else /* !MZ_SUPPORTED */
 607
 608 int DOSVM_Enter( CONTEXT86 *context )
 609 {
 610  ERR_(module)("DOS realmode not supported on this architecture!\n");
 611  return -1;
 612 }
 613
 614 void DOSVM_Wait( int read_pipe, HANDLE hObject) {}
 615 void DOSVM_PIC_ioport_out( WORD port, BYTE val) {}
 616 void DOSVM_SetTimer( unsigned ticks ) {}
 617 unsigned DOSVM_GetTimer( void ) { return 0; }
 618 void DOSVM_SetSystemData( int id, void *data ) { free(data); }
 619 void* DOSVM_GetSystemData( int id ) { return NULL; }
 620 void DOSVM_QueueEvent( int irq, int priority, void (*relay)(LPDOSTASK,CONTEXT86*,void*), void *data) {}
 621
 622 #endif