loader/task.c

   1 /*
   2  * Task functions
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include "windows.h"
  11 #include "task.h"
  12 #include "callback.h"
  13 #include "global.h"
  14 #include "instance.h"
  15 #include "module.h"
  16 #include "neexe.h"
  17 #include "selectors.h"
  18 #include "toolhelp.h"
  19 #include "wine.h"
  20 #include "stddebug.h"
  21 #include "debug.h"
  22
  23   /* Min. number of thunks allocated when creating a new segment */
  24 #define MIN_THUNKS  32
  25
  26   /* 32-bit stack size for each task */
  27   /* Must not be greater than 64k, or MAKE_SEGPTR won't work */
  28 #define STACK32_SIZE 0x10000
  29
  30
  31 static HTASK hFirstTask = 0;
  32 static HTASK hCurrentTask = 0;
  33 static HTASK hTaskToKill = 0;
  34 static WORD nTaskCount = 0;
  35
  36   /* TASK_Reschedule() 16-bit entry point */
  37 static FARPROC TASK_RescheduleProc;
  38
  39 #define TASK_SCHEDULE()  CallTo16_word_(TASK_RescheduleProc,0)
  40
  41
  42 /***********************************************************************
  43  *           TASK_Init
  44  */
  45 BOOL TASK_Init(void)
  46 {
  47     TASK_RescheduleProc = (FARPROC)GetWndProcEntry16( "TASK_Reschedule" );
  48     return TRUE;
  49 }
  50
  51
  52 /***********************************************************************
  53  *           TASK_LinkTask
  54  */
  55 static void TASK_LinkTask( HTASK hTask )
  56 {
  57     HTASK *prevTask;
  58     TDB *pTask;
  59
  60     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
  61     prevTask = &hFirstTask;
  62     while (*prevTask)
  63     {
  64         TDB *prevTaskPtr = (TDB *)GlobalLock( *prevTask );
  65         if (prevTaskPtr->priority >= pTask->priority) break;
  66         prevTask = &prevTaskPtr->hNext;
  67     }
  68     pTask->hNext = *prevTask;
  69     *prevTask = hTask;
  70     nTaskCount++;
  71 }
  72
  73
  74 /***********************************************************************
  75  *           TASK_UnlinkTask
  76  */
  77 static void TASK_UnlinkTask( HTASK hTask )
  78 {
  79     HTASK *prevTask;
  80     TDB *pTask;
  81
  82     prevTask = &hFirstTask;
  83     while (*prevTask && (*prevTask != hTask))
  84     {
  85         pTask = (TDB *)GlobalLock( *prevTask );
  86         prevTask = &pTask->hNext;
  87     }
  88     if (*prevTask)
  89     {
  90         pTask = (TDB *)GlobalLock( *prevTask );
  91         *prevTask = pTask->hNext;
  92         pTask->hNext = 0;
  93         nTaskCount--;
  94     }
  95 }
  96
  97
  98 /***********************************************************************
  99  *           TASK_CreateThunks
 100  *
 101  * Create a thunk free-list in segment 'handle', starting from offset 'offset'
 102  * and containing 'count' entries.
 103  */
 104 static void TASK_CreateThunks( HGLOBAL handle, WORD offset, WORD count )
 105 {
 106     int i;
 107     WORD free;
 108     THUNKS *pThunk;
 109
 110     pThunk = (THUNKS *)((BYTE *)GlobalLock( handle ) + offset);
 111     pThunk->next = 0;
 112     pThunk->magic = THUNK_MAGIC;
 113     pThunk->free = (int)&pThunk->thunks - (int)pThunk;
 114     free = pThunk->free;
 115     for (i = 0; i < count-1; i++)
 116     {
 117         free += 8;  /* Offset of next thunk */
 118         pThunk->thunks[4*i] = free;
 119     }
 120     pThunk->thunks[4*i] = 0;  /* Last thunk */
 121 }
 122
 123
 124 /***********************************************************************
 125  *           TASK_AllocThunk
 126  *
 127  * Allocate a thunk for MakeProcInstance().
 128  */
 129 static SEGPTR TASK_AllocThunk( HTASK hTask )
 130 {
 131     TDB *pTask;
 132     THUNKS *pThunk;
 133     WORD sel, base;
 134
 135     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 136     sel = pTask->hCSAlias;
 137     pThunk = &pTask->thunks;
 138     base = (int)pThunk - (int)pTask;
 139     while (!pThunk->free)
 140     {
 141         sel = pThunk->next;
 142         if (!sel)  /* Allocate a new segment */
 143         {
 144             sel = GLOBAL_Alloc( GMEM_FIXED, sizeof(THUNKS) + (MIN_THUNKS-1)*8,
 145                                 pTask->hPDB, TRUE, FALSE, FALSE );
 146             if (!sel) return (SEGPTR)0;
 147             TASK_CreateThunks( sel, 0, MIN_THUNKS );
 148             pThunk->next = sel;
 149         }
 150         pThunk = (THUNKS *)GlobalLock( sel );
 151         base = 0;
 152     }
 153     base += pThunk->free;
 154     pThunk->free = *(WORD *)((BYTE *)pThunk + pThunk->free);
 155     return MAKELONG( base, sel );
 156 }
 157
 158
 159 /***********************************************************************
 160  *           TASK_FreeThunk
 161  *
 162  * Free a MakeProcInstance() thunk.
 163  */
 164 static BOOL TASK_FreeThunk( HTASK hTask, SEGPTR thunk )
 165 {
 166     TDB *pTask;
 167     THUNKS *pThunk;
 168     WORD sel, base;
 169
 170     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 171     sel = pTask->hCSAlias;
 172     pThunk = &pTask->thunks;
 173     base = (int)pThunk - (int)pTask;
 174     while (sel && (sel != HIWORD(thunk)))
 175     {
 176         sel = pThunk->next;
 177         pThunk = (THUNKS *)GlobalLock( sel );
 178         base = 0;
 179     }
 180     if (!sel) return FALSE;
 181     *(WORD *)((BYTE *)pThunk + LOWORD(thunk) - base) = pThunk->free;
 182     pThunk->free = LOWORD(thunk) - base;
 183     return TRUE;
 184 }
 185
 186
 187 /***********************************************************************
 188  *           TASK_CallToStart
 189  *
 190  * 32-bit entry point for a new task. This function is responsible for
 191  * setting up the registers and jumping to the 16-bit entry point.
 192  */
 193 static void TASK_CallToStart(void)
 194 {
 195     int cs_reg, ds_reg, ip_reg;
 196     TDB *pTask = (TDB *)GlobalLock( hCurrentTask );
 197     NE_MODULE *pModule = (NE_MODULE *)GlobalLock( pTask->hModule );
 198     SEGTABLEENTRY *pSegTable = NE_SEG_TABLE( pModule );
 199
 200     /* Registers at initialization must be:
 201      * ax   zero
 202      * bx   stack size in bytes
 203      * cx   heap size in bytes
 204      * si   previous app instance
 205      * di   current app instance
 206      * bp   zero
 207      * es   selector to the PSP
 208      * ds   dgroup of the application
 209      * ss   stack selector
 210      * sp   top of the stack
 211      */
 212
 213     cs_reg = pSegTable[pModule->cs - 1].selector;
 214     ip_reg = pModule->ip;
 215     ds_reg = pSegTable[pModule->dgroup - 1].selector;
 216     IF1632_Saved16_ss = pTask->ss;
 217     IF1632_Saved16_sp = pTask->sp;
 218     dprintf_task( stddeb, "Starting main program: cs:ip=%04x:%04x ds=%04x ss:sp=%04x:%04x\n",
 219                  cs_reg, ip_reg, ds_reg,
 220                  IF1632_Saved16_ss, IF1632_Saved16_sp);
 221     CallTo16_regs_( (FARPROC)(cs_reg << 16 | ip_reg), ds_reg,
 222                    pTask->hPDB /*es*/, 0 /*bp*/, 0 /*ax*/,
 223                    pModule->stack_size /*bx*/, pModule->heap_size /*cx*/,
 224                    0 /*dx*/, 0 /*si*/, ds_reg /*di*/ );
 225     /* This should never return */
 226     fprintf( stderr, "TASK_CallToStart: Main program returned!\n" );
 227     exit(1);
 228 }
 229
 230
 231 /***********************************************************************
 232  *           TASK_CreateTask
 233  */
 234 HTASK TASK_CreateTask( HMODULE hModule, HANDLE hInstance, HANDLE hPrevInstance,
 235                        HANDLE hEnvironment, char *cmdLine, WORD cmdShow )
 236 {
 237     HTASK hTask;
 238     TDB *pTask;
 239     NE_MODULE *pModule;
 240     SEGTABLEENTRY *pSegTable;
 241     LPSTR name;
 242     char *stack16Top, *stack32Top;
 243     STACK16FRAME *frame16;
 244     STACK32FRAME *frame32;
 245     extern DWORD CALL16_RetAddr_word;
 246
 247     if (!(pModule = (NE_MODULE *)GlobalLock( hModule ))) return 0;
 248     pSegTable = NE_SEG_TABLE( pModule );
 249
 250       /* Allocate the task structure */
 251
 252     hTask = GLOBAL_Alloc( GMEM_FIXED | GMEM_ZEROINIT, sizeof(TDB),
 253                           hModule, FALSE, FALSE, FALSE );
 254     if (!hTask) return 0;
 255     pTask = (TDB *)GlobalLock( hTask );
 256
 257       /* Fill the task structure */
 258
 259     pTask->nEvents       = 1;  /* So the task can be started */
 260     pTask->hSelf         = hTask;
 261     pTask->flags         = 0;
 262     pTask->version       = pModule->expected_version;
 263     pTask->hInstance     = hInstance;
 264     pTask->hPrevInstance = hPrevInstance;
 265     pTask->hModule       = hModule;
 266     pTask->hParent       = hCurrentTask;
 267     pTask->curdrive      = 'C' - 'A' + 0x80;
 268     pTask->magic         = TDB_MAGIC;
 269     pTask->nCmdShow      = cmdShow;
 270     strcpy( pTask->curdir, "WINDOWS" );
 271
 272       /* Create the thunks block */
 273
 274     TASK_CreateThunks( hTask, (int)&pTask->thunks - (int)pTask, 7 );
 275
 276       /* Copy the module name */
 277
 278     name = MODULE_GetModuleName( hModule );
 279     strncpy( pTask->module_name, name, sizeof(pTask->module_name) );
 280
 281       /* Fill the PDB */
 282
 283     pTask->pdb.int20 = 0x20cd;
 284     pTask->pdb.dispatcher[0] = 0x9a;
 285     *(DWORD *)&pTask->pdb.dispatcher[1] = MODULE_GetEntryPoint( GetModuleHandle("KERNEL"), 102 );  /* KERNEL.102 is DOS3Call() */
 286     pTask->pdb.savedint22 = MODULE_GetEntryPoint( GetModuleHandle("KERNEL"),
 287                                     137 );  /* KERNEL.137 is FatalAppExit() */
 288     pTask->pdb.savedint23 = pTask->pdb.savedint22;
 289     pTask->pdb.savedint24 = pTask->pdb.savedint22;
 290     pTask->pdb.environment = hEnvironment;
 291     strncpy( pTask->pdb.cmdLine + 1, cmdLine, 126 );
 292     pTask->pdb.cmdLine[127] = '\0';
 293     pTask->pdb.cmdLine[0] = strlen( pTask->pdb.cmdLine + 1 );
 294
 295       /* Get the compatibility flags */
 296
 297     pTask->compat_flags = GetProfileInt( name, "Compatibility", 0 );
 298
 299       /* Allocate a selector for the PDB */
 300
 301     pTask->hPDB = GLOBAL_CreateBlock( GMEM_FIXED, &pTask->pdb, sizeof(PDB),
 302                                       hModule, FALSE, FALSE, FALSE );
 303
 304       /* Allocate a code segment alias for the TDB */
 305
 306     pTask->hCSAlias = GLOBAL_CreateBlock( GMEM_FIXED, (void *)pTask,
 307                                           sizeof(TDB), pTask->hPDB, TRUE,
 308                                           FALSE, FALSE );
 309
 310       /* Set the owner of the environment block */
 311
 312     FarSetOwner( pTask->pdb.environment, pTask->hPDB );
 313
 314       /* Default DTA overwrites command-line */
 315
 316     pTask->dta = MAKELONG( (int)&pTask->pdb.cmdLine - (int)&pTask->pdb,
 317                            pTask->hPDB );
 318
 319       /* Allocate the 32-bit stack */
 320
 321     pTask->hStack32 = GLOBAL_Alloc( GMEM_FIXED, STACK32_SIZE, pTask->hPDB,
 322                                     FALSE, FALSE, FALSE );
 323
 324       /* Create the 32-bit stack frame */
 325
 326     stack32Top = (char*)GlobalLock(pTask->hStack32) + STACK32_SIZE;
 327     frame32 = (STACK32FRAME *)stack32Top - 1;
 328     frame32->saved_esp = (DWORD)stack32Top;
 329     frame32->edi = 0;
 330     frame32->esi = 0;
 331     frame32->edx = 0;
 332     frame32->ecx = 0;
 333     frame32->ebx = 0;
 334     frame32->ebp = 0;
 335     frame32->retaddr = (DWORD)TASK_CallToStart;
 336     frame32->codeselector = WINE_CODE_SELECTOR;
 337     pTask->esp = (DWORD)frame32;
 338
 339       /* Create the 16-bit stack frame */
 340
 341     pTask->ss = hInstance;
 342     pTask->sp = (pModule->sp != 0) ? pModule->sp :
 343                 pSegTable[pModule->ss-1].minsize + pModule->stack_size;
 344     stack16Top = (char *)PTR_SEG_OFF_TO_LIN( pTask->ss, pTask->sp );
 345     frame16 = (STACK16FRAME *)stack16Top - 1;
 346     frame16->saved_ss = pTask->ss;
 347     frame16->saved_sp = pTask->sp;
 348     frame16->ds = pTask->hInstance;
 349     frame16->entry_point = 0;
 350     frame16->ordinal_number = 1;
 351     frame16->dll_id = 1;
 352     frame16->bp = 0;
 353     frame16->ip = LOWORD( CALL16_RetAddr_word );
 354     frame16->cs = HIWORD( CALL16_RetAddr_word );
 355     pTask->sp -= sizeof(STACK16FRAME);
 356
 357       /* If there's no 16-bit stack yet, use a part of the new task stack */
 358       /* This is only needed to have a stack to switch from on the first  */
 359       /* call to DirectedYield(). */
 360
 361     if (!IF1632_Saved16_ss)
 362     {
 363         IF1632_Saved16_ss = pTask->ss;
 364         IF1632_Saved16_sp = pTask->sp;
 365     }
 366
 367       /* Add the task to the linked list */
 368
 369     TASK_LinkTask( hTask );
 370
 371     dprintf_task( stddeb, "CreateTask: module='%s' cmdline='%s' task=%04x\n",
 372                   name, cmdLine, hTask );
 373
 374     return hTask;
 375 }
 376
 377
 378 /***********************************************************************
 379  *           TASK_DeleteTask
 380  */
 381 void TASK_DeleteTask( HTASK hTask )
 382 {
 383     TDB *pTask;
 384
 385     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 386
 387       /* Free the task module */
 388
 389     FreeModule( pTask->hModule );
 390
 391       /* Free all memory used by this task (including the 32-bit stack, */
 392       /* the environment block and the thunk segments). */
 393
 394     GlobalFreeAll( pTask->hPDB );
 395
 396       /* Free the selector aliases */
 397
 398     GLOBAL_FreeBlock( pTask->hCSAlias );
 399     GLOBAL_FreeBlock( pTask->hPDB );
 400
 401       /* Free the task structure itself */
 402
 403     GlobalFree( hTask );
 404 }
 405
 406
 407 /***********************************************************************
 408  *           TASK_KillCurrentTask
 409  *
 410  * Kill the currently running task. As it's not possible to kill the
 411  * current task like this, it is simply marked for destruction, and will
 412  * be killed when either TASK_Reschedule or this function is called again
 413  * in the context of another task.
 414  */
 415 void TASK_KillCurrentTask( int exitCode )
 416 {
 417     if (hTaskToKill && (hTaskToKill != hCurrentTask))
 418     {
 419         /* If another task is already marked for destruction, */
 420         /* we call kill it now, as we are in another context. */
 421         TASK_DeleteTask( hTaskToKill );
 422     }
 423
 424     if (nTaskCount <= 1)
 425     {
 426         dprintf_task( stddeb, "Killing the last task, exiting\n" );
 427         exit(0);
 428     }
 429
 430     /* Remove the task from the list to be sure we never switch back to it */
 431     TASK_UnlinkTask( hCurrentTask );
 432
 433     hTaskToKill = hCurrentTask;
 434     Yield();
 435     /* We never return from Yield() */
 436 }
 437
 438
 439 /***********************************************************************
 440  *           TASK_Reschedule
 441  *
 442  * This is where all the magic of task-switching happens!
 443  *
 444  * This function should only be called via the TASK_SCHEDULE() macro, to make
 445  * sure that all the context is saved correctly.
 446  */
 447 void TASK_Reschedule(void)
 448 {
 449     TDB *pOldTask = NULL, *pNewTask;
 450     HTASK hTask = 0;
 451
 452       /* First check if there's a task to kill */
 453
 454     if (hTaskToKill && (hTaskToKill != hCurrentTask))
 455         TASK_DeleteTask( hTaskToKill );
 456
 457       /* Find a task to yield to */
 458
 459     pOldTask = (TDB *)GlobalLock( hCurrentTask );
 460     if (pOldTask && pOldTask->hYieldTo)
 461     {
 462         /* If a task is stored in hYieldTo of the current task (put there */
 463         /* by DirectedYield), yield to it only if it has events pending.  */
 464         hTask = pOldTask->hYieldTo;
 465         if (!(pNewTask = (TDB *)GlobalLock( hTask )) || !pNewTask->nEvents)
 466             hTask = 0;
 467     }
 468
 469     if (!hTask)
 470     {
 471         hTask = hFirstTask;
 472         while (hTask)
 473         {
 474             pNewTask = (TDB *)GlobalLock( hTask );
 475             if (pNewTask->nEvents && (hTask != hCurrentTask)) break;
 476             hTask = pNewTask->hNext;
 477         }
 478     }
 479
 480      /* If there's a task to kill, switch to any other task, */
 481      /* even if it doesn't have events pending. */
 482
 483     if (!hTask && hTaskToKill) hTask = hFirstTask;
 484
 485     if (!hTask) return;  /* Do nothing */
 486
 487     pNewTask = (TDB *)GlobalLock( hTask );
 488     dprintf_task( stddeb, "Switching to task %04x (%.8s)\n",
 489                   hTask, pNewTask->module_name );
 490
 491       /* Save the stacks of the previous task (if any) */
 492
 493     if (pOldTask)
 494     {
 495         pOldTask->ss  = IF1632_Saved16_ss;
 496         pOldTask->sp  = IF1632_Saved16_sp;
 497         pOldTask->esp = IF1632_Saved32_esp;
 498     }
 499
 500      /* Make the task the last in the linked list (round-robin scheduling) */
 501
 502     pNewTask->priority++;
 503     TASK_UnlinkTask( hTask );
 504     TASK_LinkTask( hTask );
 505     pNewTask->priority--;
 506
 507       /* Switch to the new stack */
 508
 509     hCurrentTask = hTask;
 510     IF1632_Saved16_ss   = pNewTask->ss;
 511     IF1632_Saved16_sp   = pNewTask->sp;
 512     IF1632_Saved32_esp  = pNewTask->esp;
 513     IF1632_Stack32_base = WIN16_GlobalLock( pNewTask->hStack32 );
 514 }
 515
 516
 517 /***********************************************************************
 518  *           InitTask  (KERNEL.91)
 519  */
 520 void InitTask( struct sigcontext_struct context )
 521 {
 522     TDB *pTask;
 523     NE_MODULE *pModule;
 524
 525     context.sc_eax = 0;
 526     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return;
 527     if (!(pModule = (NE_MODULE *)GlobalLock( pTask->hModule ))) return;
 528
 529     NE_InitializeDLLs( pTask->hModule );
 530
 531     /* Registers on return are:
 532      * ax     1 if OK, 0 on error
 533      * cx     stack limit in bytes
 534      * dx     cmdShow parameter
 535      * si     instance handle of the previous instance
 536      * di     instance handle of the new task
 537      * es:bx  pointer to command-line inside PSP
 538      */
 539     context.sc_eax = 1;
 540     context.sc_ebx = 0x81;
 541     context.sc_ecx = pModule->stack_size;
 542     context.sc_edx = pTask->nCmdShow;
 543     context.sc_esi = pTask->hPrevInstance;
 544     context.sc_edi = pTask->hInstance;
 545     context.sc_es  = pTask->hPDB;
 546 }
 547
 548
 549 /***********************************************************************
 550  *           WaitEvent  (KERNEL.30)
 551  */
 552 BOOL WaitEvent( HTASK hTask )
 553 {
 554     TDB *pTask;
 555
 556     if (!hTask) hTask = hCurrentTask;
 557     pTask = (TDB *)GlobalLock( hTask );
 558     if (pTask->nEvents > 0)
 559     {
 560         pTask->nEvents--;
 561         return FALSE;
 562     }
 563     TASK_SCHEDULE();
 564     /* When we get back here, we have an event */
 565     pTask->nEvents--;
 566     return TRUE;
 567 }
 568
 569
 570 /***********************************************************************
 571  *           PostEvent  (KERNEL.31)
 572  */
 573 void PostEvent( HTASK hTask )
 574 {
 575     TDB *pTask;
 576
 577     if (!hTask) hTask = hCurrentTask;
 578     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 579     pTask->nEvents++;
 580 }
 581
 582
 583 /***********************************************************************
 584  *           SetPriority  (KERNEL.32)
 585  */
 586 void SetPriority( HTASK hTask, int delta )
 587 {
 588     TDB *pTask;
 589     int newpriority;
 590
 591     if (!hTask) hTask = hCurrentTask;
 592     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 593     newpriority = pTask->priority + delta;
 594     if (newpriority < -32) newpriority = -32;
 595     else if (newpriority > 15) newpriority = 15;
 596
 597     pTask->priority = newpriority + 1;
 598     TASK_UnlinkTask( hTask );
 599     TASK_LinkTask( hTask );
 600     pTask->priority--;
 601 }
 602
 603
 604 /***********************************************************************
 605  *           OldYield  (KERNEL.117)
 606  */
 607 void OldYield(void)
 608 {
 609     TDB *pCurTask;
 610
 611     pCurTask = (TDB *)GlobalLock( hCurrentTask );
 612     if (pCurTask) pCurTask->nEvents++;  /* Make sure we get back here */
 613     TASK_SCHEDULE();
 614     if (pCurTask) pCurTask->nEvents--;
 615 }
 616
 617
 618 /***********************************************************************
 619  *           DirectedYield  (KERNEL.150)
 620  */
 621 void DirectedYield( HTASK hTask )
 622 {
 623     TDB *pCurTask;
 624
 625     if ((pCurTask = (TDB *)GlobalLock( hCurrentTask )) != NULL)
 626         pCurTask->hYieldTo = hTask;
 627
 628     OldYield();
 629 }
 630
 631
 632 /***********************************************************************
 633  *           Yield  (KERNEL.29)
 634  */
 635 void Yield(void)
 636 {
 637     DirectedYield( 0 );
 638 }
 639
 640
 641 /***********************************************************************
 642  *           MakeProcInstance  (KERNEL.51)
 643  */
 644 FARPROC MakeProcInstance( FARPROC func, HANDLE hInstance )
 645 {
 646     BYTE *thunk;
 647     SEGPTR thunkaddr;
 648
 649     thunkaddr = TASK_AllocThunk( hCurrentTask );
 650     if (!thunkaddr) return (FARPROC)0;
 651     thunk = PTR_SEG_TO_LIN( thunkaddr );
 652
 653     dprintf_task( stddeb, "MakeProcInstance(%08lx,%04x): got thunk %08lx\n",
 654                   (SEGPTR)func, hInstance, (SEGPTR)thunkaddr );
 655
 656     *thunk++ = 0xb8;    /* movw instance, %ax */
 657     *thunk++ = (BYTE)(hInstance & 0xff);
 658     *thunk++ = (BYTE)(hInstance >> 8);
 659     *thunk++ = 0xea;    /* ljmp func */
 660     *(DWORD *)thunk = (DWORD)func;
 661     return (FARPROC)thunkaddr;
 662 }
 663
 664
 665 /***********************************************************************
 666  *           FreeProcInstance  (KERNEL.52)
 667  */
 668 void FreeProcInstance( FARPROC func )
 669 {
 670     dprintf_task( stddeb, "FreeProcInstance(%08lx)\n", (SEGPTR)func );
 671     TASK_FreeThunk( hCurrentTask, (SEGPTR)func );
 672 }
 673
 674
 675 /**********************************************************************
 676  *          GetCodeHandle    (KERNEL.93)
 677  */
 678 HANDLE GetCodeHandle( FARPROC proc )
 679 {
 680     HANDLE handle;
 681     BYTE *thunk = (BYTE *)PTR_SEG_TO_LIN( proc );
 682
 683     /* Return the code segment containing 'proc'. */
 684     /* Not sure if this is really correct (shouldn't matter that much). */
 685
 686     /* Check if it is really a thunk */
 687     if ((thunk[0] == 0xb8) && (thunk[3] == 0xea))
 688         handle = GlobalHandle( thunk[6] + (thunk[7] << 8) );
 689     else
 690         handle = GlobalHandle( HIWORD(proc) );
 691
 692     printf( "STUB: GetCodeHandle(%08lx) returning %04x\n",
 693             (DWORD)proc, handle );
 694     return handle;
 695 }
 696
 697
 698 /***********************************************************************
 699  *           SetTaskQueue  (KERNEL.34)
 700  */
 701 HGLOBAL SetTaskQueue( HANDLE hTask, HGLOBAL hQueue )
 702 {
 703     HGLOBAL hPrev;
 704     TDB *pTask;
 705
 706     if (!hTask) hTask = hCurrentTask;
 707     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 708     hPrev = pTask->hQueue;
 709     pTask->hQueue = hQueue;
 710     return hPrev;
 711 }
 712
 713
 714 /***********************************************************************
 715  *           GetTaskQueue  (KERNEL.35)
 716  */
 717 HGLOBAL GetTaskQueue( HANDLE hTask )
 718 {
 719     TDB *pTask;
 720
 721     if (!hTask) hTask = hCurrentTask;
 722     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 723     return pTask->hQueue;
 724 }
 725
 726
 727 /***********************************************************************
 728  *           GetCurrentTask   (KERNEL.36)
 729  */
 730 HTASK GetCurrentTask(void)
 731 {
 732       /* Undocumented: first task is returned in high word */
 733     return MAKELONG( hCurrentTask, hFirstTask );
 734 }
 735
 736
 737 /***********************************************************************
 738  *           GetCurrentPDB   (KERNEL.37)
 739  */
 740 WORD GetCurrentPDB(void)
 741 {
 742     TDB *pTask;
 743
 744     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
 745     return pTask->hPDB;
 746 }
 747
 748
 749 /***********************************************************************
 750  *           GetNumTasks   (KERNEL.152)
 751  */
 752 WORD GetNumTasks(void)
 753 {
 754     return nTaskCount;
 755 }
 756
 757
 758 /***********************************************************************
 759  *           GetTaskDS   (KERNEL.155)
 760  */
 761 WORD GetTaskDS(void)
 762 {
 763     TDB *pTask;
 764
 765     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
 766     return pTask->hInstance;
 767 }
 768
 769
 770 /***********************************************************************
 771  *           IsTask   (KERNEL.320)
 772  */
 773 BOOL IsTask( HTASK hTask )
 774 {
 775     TDB *pTask;
 776
 777     if (!(pTask = (TDB *)GlobalLock( hTask ))) return FALSE;
 778     if (GlobalSize( hTask ) < sizeof(TDB)) return FALSE;
 779     return (pTask->magic == TDB_MAGIC);
 780 }
 781
 782
 783 /***********************************************************************
 784  *           GetExePtr   (KERNEL.133)
 785  */
 786 HMODULE GetExePtr( HANDLE handle )
 787 {
 788     char *ptr;
 789     HTASK hTask;
 790     HANDLE owner;
 791
 792       /* Check for module handle */
 793
 794     if (!(ptr = GlobalLock( handle ))) return 0;
 795     if (((NE_MODULE *)ptr)->magic == NE_SIGNATURE) return handle;
 796
 797       /* Check the owner for module handle */
 798
 799     owner = FarGetOwner( handle );
 800     if (!(ptr = GlobalLock( owner ))) return 0;
 801     if (((NE_MODULE *)ptr)->magic == NE_SIGNATURE) return owner;
 802
 803       /* Search for this handle and its owner inside all tasks */
 804
 805     hTask = hFirstTask;
 806     while (hTask)
 807     {
 808         TDB *pTask = (TDB *)GlobalLock( hTask );
 809         if ((hTask == handle) ||
 810             (pTask->hInstance == handle) ||
 811             (pTask->hQueue == handle) ||
 812             (pTask->hPDB == handle)) return pTask->hModule;
 813         if ((hTask == owner) ||
 814             (pTask->hInstance == owner) ||
 815             (pTask->hQueue == owner) ||
 816             (pTask->hPDB == owner)) return pTask->hModule;
 817     }
 818     return 0;
 819 }
 820
 821
 822 /***********************************************************************
 823  *           TaskFirst   (TOOLHELP.63)
 824  */
 825 BOOL TaskFirst( TASKENTRY *lpte )
 826 {
 827     lpte->hNext = hFirstTask;
 828     return TaskNext( lpte );
 829 }
 830
 831
 832 /***********************************************************************
 833  *           TaskNext   (TOOLHELP.64)
 834  */
 835 BOOL TaskNext( TASKENTRY *lpte )
 836 {
 837     TDB *pTask;
 838     INSTANCEDATA *pInstData;
 839
 840     dprintf_toolhelp( stddeb, "TaskNext(%p): task=%04x\n", lpte, lpte->hNext );
 841     if (!lpte->hNext) return FALSE;
 842     pTask = (TDB *)GlobalLock( lpte->hNext );
 843     if (!pTask || pTask->magic != TDB_MAGIC) return FALSE;
 844     pInstData = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN( pTask->hInstance, 0 );
 845     lpte->hTask         = lpte->hNext;
 846     lpte->hTaskParent   = pTask->hParent;
 847     lpte->hInst         = pTask->hInstance;
 848     lpte->hModule       = pTask->hModule;
 849     lpte->wSS           = pTask->ss;
 850     lpte->wSP           = pTask->sp;
 851     lpte->wStackTop     = pInstData->stacktop;
 852     lpte->wStackMinimum = pInstData->stackmin;
 853     lpte->wStackBottom  = pInstData->stackbottom;
 854     lpte->wcEvents      = pTask->nEvents;
 855     lpte->hQueue        = pTask->hQueue;
 856     strncpy( lpte->szModule, pTask->module_name, 8 );
 857     lpte->szModule[8]   = '\0';
 858     lpte->wPSPOffset    = 0x100;  /*??*/
 859     lpte->hNext         = pTask->hNext;
 860     return TRUE;
 861 }
 862
 863
 864 /***********************************************************************
 865  *           TaskFindHandle   (TOOLHELP.65)
 866  */
 867 BOOL TaskFindHandle( TASKENTRY *lpte, HTASK hTask )
 868 {
 869     lpte->hNext = hTask;
 870     return TaskNext( lpte );
 871 }