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 "debugger.h"
  14 #include "global.h"
  15 #include "instance.h"
  16 #include "miscemu.h"
  17 #include "module.h"
  18 #include "neexe.h"
  19 #include "options.h"
  20 #include "selectors.h"
  21 #include "toolhelp.h"
  22 #include "stddebug.h"
  23 #include "debug.h"
  24 #include "dde_proc.h"
  25
  26   /* Min. number of thunks allocated when creating a new segment */
  27 #define MIN_THUNKS  32
  28
  29   /* 32-bit stack size for each task */
  30   /* Must not be greater than 64k, or MAKE_SEGPTR won't work */
  31 #define STACK32_SIZE 0x10000
  32
  33
  34 static HTASK hFirstTask = 0;
  35 static HTASK hCurrentTask = 0;
  36 static HTASK hTaskToKill = 0;
  37 static HTASK hLockedTask = 0;
  38 static WORD nTaskCount = 0;
  39
  40   /* TASK_Reschedule() 16-bit entry point */
  41 static FARPROC TASK_RescheduleProc;
  42
  43 #define TASK_SCHEDULE()  CallTo16_word_(TASK_RescheduleProc,0)
  44
  45
  46 /***********************************************************************
  47  *           TASK_Init
  48  */
  49 BOOL TASK_Init(void)
  50 {
  51     TASK_RescheduleProc = (FARPROC)GetWndProcEntry16( "TASK_Reschedule" );
  52     return TRUE;
  53 }
  54
  55
  56 /***********************************************************************
  57  *           TASK_LinkTask
  58  */
  59 static void TASK_LinkTask( HTASK hTask )
  60 {
  61     HTASK *prevTask;
  62     TDB *pTask;
  63
  64     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
  65     prevTask = &hFirstTask;
  66     while (*prevTask)
  67     {
  68         TDB *prevTaskPtr = (TDB *)GlobalLock( *prevTask );
  69         if (prevTaskPtr->priority >= pTask->priority) break;
  70         prevTask = &prevTaskPtr->hNext;
  71     }
  72     pTask->hNext = *prevTask;
  73     *prevTask = hTask;
  74     nTaskCount++;
  75 }
  76
  77
  78 /***********************************************************************
  79  *           TASK_UnlinkTask
  80  */
  81 static void TASK_UnlinkTask( HTASK hTask )
  82 {
  83     HTASK *prevTask;
  84     TDB *pTask;
  85
  86     prevTask = &hFirstTask;
  87     while (*prevTask && (*prevTask != hTask))
  88     {
  89         pTask = (TDB *)GlobalLock( *prevTask );
  90         prevTask = &pTask->hNext;
  91     }
  92     if (*prevTask)
  93     {
  94         pTask = (TDB *)GlobalLock( *prevTask );
  95         *prevTask = pTask->hNext;
  96         pTask->hNext = 0;
  97         nTaskCount--;
  98     }
  99 }
 100
 101
 102 /***********************************************************************
 103  *           TASK_CreateThunks
 104  *
 105  * Create a thunk free-list in segment 'handle', starting from offset 'offset'
 106  * and containing 'count' entries.
 107  */
 108 static void TASK_CreateThunks( HGLOBAL handle, WORD offset, WORD count )
 109 {
 110     int i;
 111     WORD free;
 112     THUNKS *pThunk;
 113
 114     pThunk = (THUNKS *)((BYTE *)GlobalLock( handle ) + offset);
 115     pThunk->next = 0;
 116     pThunk->magic = THUNK_MAGIC;
 117     pThunk->free = (int)&pThunk->thunks - (int)pThunk;
 118     free = pThunk->free;
 119     for (i = 0; i < count-1; i++)
 120     {
 121         free += 8;  /* Offset of next thunk */
 122         pThunk->thunks[4*i] = free;
 123     }
 124     pThunk->thunks[4*i] = 0;  /* Last thunk */
 125 }
 126
 127
 128 /***********************************************************************
 129  *           TASK_AllocThunk
 130  *
 131  * Allocate a thunk for MakeProcInstance().
 132  */
 133 static SEGPTR TASK_AllocThunk( HTASK hTask )
 134 {
 135     TDB *pTask;
 136     THUNKS *pThunk;
 137     WORD sel, base;
 138
 139     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 140     sel = pTask->hCSAlias;
 141     pThunk = &pTask->thunks;
 142     base = (int)pThunk - (int)pTask;
 143     while (!pThunk->free)
 144     {
 145         sel = pThunk->next;
 146         if (!sel)  /* Allocate a new segment */
 147         {
 148             sel = GLOBAL_Alloc( GMEM_FIXED, sizeof(THUNKS) + (MIN_THUNKS-1)*8,
 149                                 pTask->hPDB, TRUE, FALSE, FALSE );
 150             if (!sel) return (SEGPTR)0;
 151             TASK_CreateThunks( sel, 0, MIN_THUNKS );
 152             pThunk->next = sel;
 153         }
 154         pThunk = (THUNKS *)GlobalLock( sel );
 155         base = 0;
 156     }
 157     base += pThunk->free;
 158     pThunk->free = *(WORD *)((BYTE *)pThunk + pThunk->free);
 159     return MAKELONG( base, sel );
 160 }
 161
 162
 163 /***********************************************************************
 164  *           TASK_FreeThunk
 165  *
 166  * Free a MakeProcInstance() thunk.
 167  */
 168 static BOOL TASK_FreeThunk( HTASK hTask, SEGPTR thunk )
 169 {
 170     TDB *pTask;
 171     THUNKS *pThunk;
 172     WORD sel, base;
 173
 174     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 175     sel = pTask->hCSAlias;
 176     pThunk = &pTask->thunks;
 177     base = (int)pThunk - (int)pTask;
 178     while (sel && (sel != HIWORD(thunk)))
 179     {
 180         sel = pThunk->next;
 181         pThunk = (THUNKS *)GlobalLock( sel );
 182         base = 0;
 183     }
 184     if (!sel) return FALSE;
 185     *(WORD *)((BYTE *)pThunk + LOWORD(thunk) - base) = pThunk->free;
 186     pThunk->free = LOWORD(thunk) - base;
 187     return TRUE;
 188 }
 189
 190
 191 /***********************************************************************
 192  *           TASK_CallToStart
 193  *
 194  * 32-bit entry point for a new task. This function is responsible for
 195  * setting up the registers and jumping to the 16-bit entry point.
 196  */
 197 static void TASK_CallToStart(void)
 198 {
 199     int cs_reg, ds_reg, ip_reg;
 200     TDB *pTask = (TDB *)GlobalLock( hCurrentTask );
 201     NE_MODULE *pModule = (NE_MODULE *)GlobalLock( pTask->hModule );
 202     SEGTABLEENTRY *pSegTable = NE_SEG_TABLE( pModule );
 203
 204     /* Registers at initialization must be:
 205      * ax   zero
 206      * bx   stack size in bytes
 207      * cx   heap size in bytes
 208      * si   previous app instance
 209      * di   current app instance
 210      * bp   zero
 211      * es   selector to the PSP
 212      * ds   dgroup of the application
 213      * ss   stack selector
 214      * sp   top of the stack
 215      */
 216
 217     cs_reg = pSegTable[pModule->cs - 1].selector;
 218     ip_reg = pModule->ip;
 219     ds_reg = pSegTable[pModule->dgroup - 1].selector;
 220     IF1632_Saved16_ss = pTask->ss;
 221     IF1632_Saved16_sp = pTask->sp;
 222     dprintf_task( stddeb, "Starting main program: cs:ip=%04x:%04x ds=%04x ss:sp=%04x:%04x\n",
 223                  cs_reg, ip_reg, ds_reg,
 224                  IF1632_Saved16_ss, IF1632_Saved16_sp);
 225
 226     CallTo16_regs_( (FARPROC)(cs_reg << 16 | ip_reg), ds_reg,
 227                    pTask->hPDB /*es*/, 0 /*bp*/, 0 /*ax*/,
 228                    pModule->stack_size /*bx*/, pModule->heap_size /*cx*/,
 229                    0 /*dx*/, 0 /*si*/, ds_reg /*di*/ );
 230     /* This should never return */
 231     fprintf( stderr, "TASK_CallToStart: Main program returned!\n" );
 232     exit(1);
 233 }
 234
 235
 236 /***********************************************************************
 237  *           TASK_CreateTask
 238  */
 239 HTASK TASK_CreateTask( HMODULE hModule, HANDLE hInstance, HANDLE hPrevInstance,
 240                        HANDLE hEnvironment, char *cmdLine, WORD cmdShow )
 241 {
 242     HTASK hTask;
 243     TDB *pTask;
 244     NE_MODULE *pModule;
 245     SEGTABLEENTRY *pSegTable;
 246     LPSTR name;
 247     char *stack16Top, *stack32Top;
 248     STACK16FRAME *frame16;
 249     STACK32FRAME *frame32;
 250     extern DWORD CALL16_RetAddr_word;
 251     char filename[256];
 252
 253     if (!(pModule = (NE_MODULE *)GlobalLock( hModule ))) return 0;
 254     pSegTable = NE_SEG_TABLE( pModule );
 255
 256       /* Allocate the task structure */
 257
 258     hTask = GLOBAL_Alloc( GMEM_FIXED | GMEM_ZEROINIT, sizeof(TDB),
 259                           hModule, FALSE, FALSE, FALSE );
 260     if (!hTask) return 0;
 261     pTask = (TDB *)GlobalLock( hTask );
 262
 263       /* get current directory */
 264
 265     GetModuleFileName( hModule, filename, sizeof(filename) );
 266     name = strrchr(filename, '\\');
 267     if (name) *(name+1) = 0;
 268
 269       /* Fill the task structure */
 270
 271     pTask->nEvents       = 1;  /* So the task can be started */
 272     pTask->hSelf         = hTask;
 273     pTask->flags         = 0;
 274     pTask->version       = pModule->expected_version;
 275     pTask->hInstance     = hInstance;
 276     pTask->hPrevInstance = hPrevInstance;
 277     pTask->hModule       = hModule;
 278     pTask->hParent       = hCurrentTask;
 279     pTask->curdrive      = filename[0] - 'A' + 0x80;
 280     pTask->magic         = TDB_MAGIC;
 281     pTask->nCmdShow      = cmdShow;
 282     strcpy( pTask->curdir, filename+2 );
 283
 284       /* Create the thunks block */
 285
 286     TASK_CreateThunks( hTask, (int)&pTask->thunks - (int)pTask, 7 );
 287
 288       /* Copy the module name */
 289
 290     name = MODULE_GetModuleName( hModule );
 291     strncpy( pTask->module_name, name, sizeof(pTask->module_name) );
 292
 293       /* Fill the PDB */
 294
 295     pTask->pdb.int20 = 0x20cd;
 296     pTask->pdb.dispatcher[0] = 0x9a;  /* ljmp */
 297     *(DWORD *)&pTask->pdb.dispatcher[1] = MODULE_GetEntryPoint( GetModuleHandle("KERNEL"), 102 );  /* KERNEL.102 is DOS3Call() */
 298     pTask->pdb.savedint22 = INT_GetHandler( 0x22 );
 299     pTask->pdb.savedint23 = INT_GetHandler( 0x23 );
 300     pTask->pdb.savedint24 = INT_GetHandler( 0x24 );
 301     pTask->pdb.environment = hEnvironment;
 302     strncpy( pTask->pdb.cmdLine + 1, cmdLine, 126 );
 303     pTask->pdb.cmdLine[127] = '\0';
 304     pTask->pdb.cmdLine[0] = strlen( pTask->pdb.cmdLine + 1 );
 305
 306       /* Get the compatibility flags */
 307
 308     pTask->compat_flags = GetProfileInt( name, "Compatibility", 0 );
 309
 310       /* Allocate a selector for the PDB */
 311
 312     pTask->hPDB = GLOBAL_CreateBlock( GMEM_FIXED, &pTask->pdb, sizeof(PDB),
 313                                       hModule, FALSE, FALSE, FALSE, NULL );
 314
 315       /* Allocate a code segment alias for the TDB */
 316
 317     pTask->hCSAlias = GLOBAL_CreateBlock( GMEM_FIXED, (void *)pTask,
 318                                           sizeof(TDB), pTask->hPDB, TRUE,
 319                                           FALSE, FALSE, NULL );
 320
 321       /* Set the owner of the environment block */
 322
 323     FarSetOwner( pTask->pdb.environment, pTask->hPDB );
 324
 325       /* Default DTA overwrites command-line */
 326
 327     pTask->dta = MAKELONG( (int)&pTask->pdb.cmdLine - (int)&pTask->pdb,
 328                            pTask->hPDB );
 329
 330       /* Allocate the 32-bit stack */
 331
 332     pTask->hStack32 = GLOBAL_Alloc( GMEM_FIXED, STACK32_SIZE, pTask->hPDB,
 333                                     FALSE, FALSE, FALSE );
 334
 335       /* Create the 32-bit stack frame */
 336
 337     *(DWORD *)GlobalLock(pTask->hStack32) = 0xDEADBEEF;
 338     stack32Top = (char*)GlobalLock(pTask->hStack32) + STACK32_SIZE;
 339     frame32 = (STACK32FRAME *)stack32Top - 1;
 340     frame32->saved_esp = (DWORD)stack32Top;
 341     frame32->edi = 0;
 342     frame32->esi = 0;
 343     frame32->edx = 0;
 344     frame32->ecx = 0;
 345     frame32->ebx = 0;
 346     frame32->ebp = 0;
 347     frame32->retaddr = (DWORD)TASK_CallToStart;
 348     frame32->codeselector = WINE_CODE_SELECTOR;
 349     pTask->esp = (DWORD)frame32;
 350
 351       /* Create the 16-bit stack frame */
 352
 353     pTask->ss = hInstance;
 354     pTask->sp = ((pModule->sp != 0) ? pModule->sp :
 355                  pSegTable[pModule->ss-1].minsize + pModule->stack_size) & ~1;
 356     stack16Top = (char *)PTR_SEG_OFF_TO_LIN( pTask->ss, pTask->sp );
 357     frame16 = (STACK16FRAME *)stack16Top - 1;
 358     frame16->saved_ss = pTask->ss;
 359     frame16->saved_sp = pTask->sp;
 360     frame16->ds = frame16->es = pTask->hInstance;
 361     frame16->entry_point = 0;
 362     frame16->ordinal_number = 24;  /* WINPROCS.24 is TASK_Reschedule */
 363     frame16->dll_id = 24; /* WINPROCS */
 364     frame16->bp = 0;
 365     frame16->ip = LOWORD( CALL16_RetAddr_word );
 366     frame16->cs = HIWORD( CALL16_RetAddr_word );
 367     pTask->sp -= sizeof(STACK16FRAME);
 368
 369       /* If there's no 16-bit stack yet, use a part of the new task stack */
 370       /* This is only needed to have a stack to switch from on the first  */
 371       /* call to DirectedYield(). */
 372
 373     if (!IF1632_Saved16_ss)
 374     {
 375         IF1632_Saved16_ss = pTask->ss;
 376         IF1632_Saved16_sp = pTask->sp;
 377     }
 378
 379       /* Add a breakpoint at the start of the task */
 380
 381     if (Options.debug)
 382     {
 383         fprintf( stderr, "Task '%s': ", name );
 384         DEBUG_AddBreakpoint( pSegTable[pModule->cs-1].selector, pModule->ip );
 385     }
 386
 387       /* Add the task to the linked list */
 388
 389     TASK_LinkTask( hTask );
 390
 391     dprintf_task( stddeb, "CreateTask: module='%s' cmdline='%s' task=%04x\n",
 392                   name, cmdLine, hTask );
 393
 394     return hTask;
 395 }
 396
 397
 398 /***********************************************************************
 399  *           TASK_DeleteTask
 400  */
 401 void TASK_DeleteTask( HTASK hTask )
 402 {
 403     TDB *pTask;
 404
 405     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 406
 407       /* Free the task module */
 408
 409     FreeModule( pTask->hModule );
 410
 411       /* Free all memory used by this task (including the 32-bit stack, */
 412       /* the environment block and the thunk segments). */
 413
 414     GlobalFreeAll( pTask->hPDB );
 415
 416       /* Free the selector aliases */
 417
 418     GLOBAL_FreeBlock( pTask->hCSAlias );
 419     GLOBAL_FreeBlock( pTask->hPDB );
 420
 421       /* Free the task structure itself */
 422
 423     GlobalFree( hTask );
 424 }
 425
 426
 427 /***********************************************************************
 428  *           TASK_KillCurrentTask
 429  *
 430  * Kill the currently running task. As it's not possible to kill the
 431  * current task like this, it is simply marked for destruction, and will
 432  * be killed when either TASK_Reschedule or this function is called again
 433  * in the context of another task.
 434  */
 435 void TASK_KillCurrentTask( int exitCode )
 436 {
 437     if (hTaskToKill && (hTaskToKill != hCurrentTask))
 438     {
 439         /* If another task is already marked for destruction, */
 440         /* we call kill it now, as we are in another context. */
 441         TASK_DeleteTask( hTaskToKill );
 442     }
 443
 444     if (nTaskCount <= 1)
 445     {
 446         dprintf_task( stddeb, "Killing the last task, exiting\n" );
 447         exit(0);
 448     }
 449
 450     /* Remove the task from the list to be sure we never switch back to it */
 451     TASK_UnlinkTask( hCurrentTask );
 452
 453     hTaskToKill = hCurrentTask;
 454     hLockedTask = 0;
 455     Yield();
 456     /* We never return from Yield() */
 457 }
 458
 459
 460 /***********************************************************************
 461  *           TASK_Reschedule
 462  *
 463  * This is where all the magic of task-switching happens!
 464  *
 465  * This function should only be called via the TASK_SCHEDULE() macro, to make
 466  * sure that all the context is saved correctly.
 467  */
 468 void TASK_Reschedule(void)
 469 {
 470     TDB *pOldTask = NULL, *pNewTask;
 471     HTASK hTask = 0;
 472
 473     dde_reschedule();
 474       /* First check if there's a task to kill */
 475
 476     if (hTaskToKill && (hTaskToKill != hCurrentTask))
 477         TASK_DeleteTask( hTaskToKill );
 478
 479       /* If current task is locked, simply return */
 480
 481     if (hLockedTask) return;
 482
 483       /* Find a task to yield to */
 484
 485     pOldTask = (TDB *)GlobalLock( hCurrentTask );
 486     if (pOldTask && pOldTask->hYieldTo)
 487     {
 488         /* If a task is stored in hYieldTo of the current task (put there */
 489         /* by DirectedYield), yield to it only if it has events pending.  */
 490         hTask = pOldTask->hYieldTo;
 491         if (!(pNewTask = (TDB *)GlobalLock( hTask )) || !pNewTask->nEvents)
 492             hTask = 0;
 493     }
 494
 495     if (!hTask)
 496     {
 497         hTask = hFirstTask;
 498         while (hTask)
 499         {
 500             pNewTask = (TDB *)GlobalLock( hTask );
 501             if (pNewTask->nEvents && (hTask != hCurrentTask)) break;
 502             hTask = pNewTask->hNext;
 503         }
 504     }
 505
 506      /* If there's a task to kill, switch to any other task, */
 507      /* even if it doesn't have events pending. */
 508
 509     if (!hTask && hTaskToKill) hTask = hFirstTask;
 510
 511     if (!hTask) return;  /* Do nothing */
 512
 513     pNewTask = (TDB *)GlobalLock( hTask );
 514     dprintf_task( stddeb, "Switching to task %04x (%.8s)\n",
 515                   hTask, pNewTask->module_name );
 516
 517       /* Save the stacks of the previous task (if any) */
 518
 519     if (pOldTask)
 520     {
 521         pOldTask->ss  = IF1632_Saved16_ss;
 522         pOldTask->sp  = IF1632_Saved16_sp;
 523         pOldTask->esp = IF1632_Saved32_esp;
 524     }
 525     else IF1632_Original32_esp = IF1632_Saved32_esp;
 526
 527      /* Make the task the last in the linked list (round-robin scheduling) */
 528
 529     pNewTask->priority++;
 530     TASK_UnlinkTask( hTask );
 531     TASK_LinkTask( hTask );
 532     pNewTask->priority--;
 533
 534       /* Switch to the new stack */
 535
 536     hCurrentTask = hTask;
 537     IF1632_Saved16_ss   = pNewTask->ss;
 538     IF1632_Saved16_sp   = pNewTask->sp;
 539     IF1632_Saved32_esp  = pNewTask->esp;
 540     IF1632_Stack32_base = WIN16_GlobalLock( pNewTask->hStack32 );
 541 }
 542
 543
 544 /***********************************************************************
 545  *           InitTask  (KERNEL.91)
 546  */
 547 void InitTask( struct sigcontext_struct context )
 548 {
 549     static int firstTask = 1;
 550     TDB *pTask;
 551     NE_MODULE *pModule;
 552     SEGTABLEENTRY *pSegTable;
 553     INSTANCEDATA *pinstance;
 554     LONG stacklow, stackhi;
 555
 556     context.sc_eax = 0;
 557     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return;
 558     if (!(pModule = (NE_MODULE *)GlobalLock( pTask->hModule ))) return;
 559
 560     if (firstTask)
 561     {
 562         extern BOOL WIDGETS_Init(void);
 563         extern BOOL WIN_CreateDesktopWindow(void);
 564
 565         /* Perform global initialisations that need a task context */
 566
 567           /* Initialize built-in window classes */
 568         if (!WIDGETS_Init()) return;
 569
 570           /* Create desktop window */
 571         if (!WIN_CreateDesktopWindow()) return;
 572
 573         firstTask = 0;
 574     }
 575
 576     NE_InitializeDLLs( pTask->hModule );
 577
 578     /* Registers on return are:
 579      * ax     1 if OK, 0 on error
 580      * cx     stack limit in bytes
 581      * dx     cmdShow parameter
 582      * si     instance handle of the previous instance
 583      * di     instance handle of the new task
 584      * es:bx  pointer to command-line inside PSP
 585      */
 586     context.sc_eax = 1;
 587     context.sc_ebx = 0x81;
 588     context.sc_ecx = pModule->stack_size;
 589     context.sc_edx = pTask->nCmdShow;
 590     context.sc_esi = pTask->hPrevInstance;
 591     context.sc_edi = pTask->hInstance;
 592     context.sc_es  = pTask->hPDB;
 593
 594     /* Initialize the local heap */
 595     if ( pModule->heap_size )
 596     {
 597         LocalInit( pTask->hInstance, 0, pModule->heap_size );
 598     }
 599
 600
 601     /* Initialize the INSTANCEDATA structure */
 602     pSegTable = NE_SEG_TABLE( pModule );
 603     stacklow = pSegTable[pModule->ss - 1].minsize;
 604     stackhi  = stacklow + pModule->stack_size;
 605     if (stackhi > 0xffff) stackhi = 0xffff;
 606     pinstance = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN(CURRENT_DS, 0);
 607     pinstance->stackbottom = stackhi; /* yup, that's right. Confused me too. */
 608     pinstance->stacktop    = stacklow;
 609     pinstance->stackmin    = IF1632_Saved16_sp;
 610 }
 611
 612
 613 /***********************************************************************
 614  *           WaitEvent  (KERNEL.30)
 615  */
 616 BOOL WaitEvent( HTASK hTask )
 617 {
 618     TDB *pTask;
 619
 620     if (!hTask) hTask = hCurrentTask;
 621     pTask = (TDB *)GlobalLock( hTask );
 622     if (pTask->nEvents > 0)
 623     {
 624         pTask->nEvents--;
 625         return FALSE;
 626     }
 627     TASK_SCHEDULE();
 628     /* When we get back here, we have an event (or the task is the only one) */
 629     if (pTask->nEvents > 0) pTask->nEvents--;
 630     return TRUE;
 631 }
 632
 633
 634 /***********************************************************************
 635  *           PostEvent  (KERNEL.31)
 636  */
 637 void PostEvent( HTASK hTask )
 638 {
 639     TDB *pTask;
 640
 641     if (!hTask) hTask = hCurrentTask;
 642     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 643     pTask->nEvents++;
 644 }
 645
 646
 647 /***********************************************************************
 648  *           SetPriority  (KERNEL.32)
 649  */
 650 void SetPriority( HTASK hTask, int delta )
 651 {
 652     TDB *pTask;
 653     int newpriority;
 654
 655     if (!hTask) hTask = hCurrentTask;
 656     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 657     newpriority = pTask->priority + delta;
 658     if (newpriority < -32) newpriority = -32;
 659     else if (newpriority > 15) newpriority = 15;
 660
 661     pTask->priority = newpriority + 1;
 662     TASK_UnlinkTask( hTask );
 663     TASK_LinkTask( hTask );
 664     pTask->priority--;
 665 }
 666
 667
 668 /***********************************************************************
 669  *           LockCurrentTask  (KERNEL.33)
 670  */
 671 HTASK LockCurrentTask( BOOL bLock )
 672 {
 673     if (bLock) hLockedTask = hCurrentTask;
 674     else hLockedTask = 0;
 675     return hLockedTask;
 676 }
 677
 678
 679 /***********************************************************************
 680  *           IsTaskLocked  (KERNEL.122)
 681  */
 682 WORD IsTaskLocked(void)
 683 {
 684     return hLockedTask;
 685 }
 686
 687
 688 /***********************************************************************
 689  *           OldYield  (KERNEL.117)
 690  */
 691 void OldYield(void)
 692 {
 693     TDB *pCurTask;
 694
 695     pCurTask = (TDB *)GlobalLock( hCurrentTask );
 696     if (pCurTask) pCurTask->nEvents++;  /* Make sure we get back here */
 697     TASK_SCHEDULE();
 698     if (pCurTask) pCurTask->nEvents--;
 699 }
 700
 701
 702 /***********************************************************************
 703  *           DirectedYield  (KERNEL.150)
 704  */
 705 void DirectedYield( HTASK hTask )
 706 {
 707     TDB *pCurTask;
 708
 709     if ((pCurTask = (TDB *)GlobalLock( hCurrentTask )) != NULL)
 710         pCurTask->hYieldTo = hTask;
 711
 712     OldYield();
 713 }
 714
 715
 716 /***********************************************************************
 717  *           Yield  (KERNEL.29)
 718  */
 719 void Yield(void)
 720 {
 721     DirectedYield( 0 );
 722 }
 723
 724
 725 /***********************************************************************
 726  *           MakeProcInstance  (KERNEL.51)
 727  */
 728 FARPROC MakeProcInstance( FARPROC func, HANDLE hInstance )
 729 {
 730     BYTE *thunk;
 731     SEGPTR thunkaddr;
 732
 733     thunkaddr = TASK_AllocThunk( hCurrentTask );
 734     if (!thunkaddr) return (FARPROC)0;
 735     thunk = PTR_SEG_TO_LIN( thunkaddr );
 736
 737     dprintf_task( stddeb, "MakeProcInstance(%08lx,%04x): got thunk %08lx\n",
 738                   (SEGPTR)func, hInstance, (SEGPTR)thunkaddr );
 739
 740     *thunk++ = 0xb8;    /* movw instance, %ax */
 741     *thunk++ = (BYTE)(hInstance & 0xff);
 742     *thunk++ = (BYTE)(hInstance >> 8);
 743     *thunk++ = 0xea;    /* ljmp func */
 744     *(DWORD *)thunk = (DWORD)func;
 745     return (FARPROC)thunkaddr;
 746 }
 747
 748
 749 /***********************************************************************
 750  *           FreeProcInstance  (KERNEL.52)
 751  */
 752 void FreeProcInstance( FARPROC func )
 753 {
 754     dprintf_task( stddeb, "FreeProcInstance(%08lx)\n", (SEGPTR)func );
 755     TASK_FreeThunk( hCurrentTask, (SEGPTR)func );
 756 }
 757
 758
 759 /**********************************************************************
 760  *          GetCodeHandle    (KERNEL.93)
 761  */
 762 HANDLE GetCodeHandle( FARPROC proc )
 763 {
 764     HANDLE handle;
 765     BYTE *thunk = (BYTE *)PTR_SEG_TO_LIN( proc );
 766
 767     /* Return the code segment containing 'proc'. */
 768     /* Not sure if this is really correct (shouldn't matter that much). */
 769
 770     /* Check if it is really a thunk */
 771     if ((thunk[0] == 0xb8) && (thunk[3] == 0xea))
 772         handle = GlobalHandle( thunk[6] + (thunk[7] << 8) );
 773     else
 774         handle = GlobalHandle( HIWORD(proc) );
 775
 776     printf( "STUB: GetCodeHandle(%08lx) returning %04x\n",
 777             (DWORD)proc, handle );
 778     return handle;
 779 }
 780
 781
 782 /***********************************************************************
 783  *           SetTaskQueue  (KERNEL.34)
 784  */
 785 HGLOBAL SetTaskQueue( HANDLE hTask, HGLOBAL hQueue )
 786 {
 787     HGLOBAL hPrev;
 788     TDB *pTask;
 789
 790     if (!hTask) hTask = hCurrentTask;
 791     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 792     hPrev = pTask->hQueue;
 793     pTask->hQueue = hQueue;
 794     return hPrev;
 795 }
 796
 797
 798 /***********************************************************************
 799  *           GetTaskQueue  (KERNEL.35)
 800  */
 801 HGLOBAL GetTaskQueue( HANDLE hTask )
 802 {
 803     TDB *pTask;
 804
 805     if (!hTask) hTask = hCurrentTask;
 806     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 807     return pTask->hQueue;
 808 }
 809
 810
 811 /***********************************************************************
 812  *           GetCurrentTask   (KERNEL.36)
 813  */
 814 HTASK GetCurrentTask(void)
 815 {
 816       /* Undocumented: first task is returned in high word */
 817     return MAKELONG( hCurrentTask, hFirstTask );
 818 }
 819
 820
 821 /***********************************************************************
 822  *           GetCurrentPDB   (KERNEL.37)
 823  */
 824 WORD GetCurrentPDB(void)
 825 {
 826     TDB *pTask;
 827
 828     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
 829     return pTask->hPDB;
 830 }
 831
 832
 833 /***********************************************************************
 834  *           GetInstanceData   (KERNEL.54)
 835  */
 836 int GetInstanceData( HANDLE instance, WORD buffer, int len )
 837 {
 838     char *ptr = (char *)GlobalLock( instance );
 839     if (!ptr || !len) return 0;
 840     if ((int)buffer + len >= 0x10000) len = 0x10000 - buffer;
 841     memcpy( ptr + buffer, (char *)GlobalLock( CURRENT_DS ) + buffer, len );
 842     return len;
 843 }
 844
 845
 846 /***********************************************************************
 847  *           GetNumTasks   (KERNEL.152)
 848  */
 849 WORD GetNumTasks(void)
 850 {
 851     return nTaskCount;
 852 }
 853
 854
 855 /***********************************************************************
 856  *           GetTaskDS   (KERNEL.155)
 857  */
 858 WORD GetTaskDS(void)
 859 {
 860     TDB *pTask;
 861
 862     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
 863     return pTask->hInstance;
 864 }
 865
 866
 867 /***********************************************************************
 868  *           IsTask   (KERNEL.320)
 869  */
 870 BOOL IsTask( HTASK hTask )
 871 {
 872     TDB *pTask;
 873
 874     if (!(pTask = (TDB *)GlobalLock( hTask ))) return FALSE;
 875     if (GlobalSize( hTask ) < sizeof(TDB)) return FALSE;
 876     return (pTask->magic == TDB_MAGIC);
 877 }
 878
 879
 880 /***********************************************************************
 881  *           GetExePtr   (KERNEL.133)
 882  */
 883 HMODULE GetExePtr( HANDLE handle )
 884 {
 885     char *ptr;
 886     HTASK hTask;
 887     HANDLE owner;
 888
 889       /* Check for module handle */
 890
 891     if (!(ptr = GlobalLock( handle ))) return 0;
 892     if (((NE_MODULE *)ptr)->magic == NE_SIGNATURE) return handle;
 893
 894       /* Check the owner for module handle */
 895
 896     owner = FarGetOwner( handle );
 897     if (!(ptr = GlobalLock( owner ))) return 0;
 898     if (((NE_MODULE *)ptr)->magic == NE_SIGNATURE) return owner;
 899
 900       /* Search for this handle and its owner inside all tasks */
 901
 902     hTask = hFirstTask;
 903     while (hTask)
 904     {
 905         TDB *pTask = (TDB *)GlobalLock( hTask );
 906         if ((hTask == handle) ||
 907             (pTask->hInstance == handle) ||
 908             (pTask->hQueue == handle) ||
 909             (pTask->hPDB == handle)) return pTask->hModule;
 910         if ((hTask == owner) ||
 911             (pTask->hInstance == owner) ||
 912             (pTask->hQueue == owner) ||
 913             (pTask->hPDB == owner)) return pTask->hModule;
 914         hTask = pTask->hNext;
 915     }
 916     return 0;
 917 }
 918
 919
 920 /***********************************************************************
 921  *           TaskFirst   (TOOLHELP.63)
 922  */
 923 BOOL TaskFirst( TASKENTRY *lpte )
 924 {
 925     lpte->hNext = hFirstTask;
 926     return TaskNext( lpte );
 927 }
 928
 929
 930 /***********************************************************************
 931  *           TaskNext   (TOOLHELP.64)
 932  */
 933 BOOL TaskNext( TASKENTRY *lpte )
 934 {
 935     TDB *pTask;
 936     INSTANCEDATA *pInstData;
 937
 938     dprintf_toolhelp( stddeb, "TaskNext(%p): task=%04x\n", lpte, lpte->hNext );
 939     if (!lpte->hNext) return FALSE;
 940     pTask = (TDB *)GlobalLock( lpte->hNext );
 941     if (!pTask || pTask->magic != TDB_MAGIC) return FALSE;
 942     pInstData = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN( pTask->hInstance, 0 );
 943     lpte->hTask         = lpte->hNext;
 944     lpte->hTaskParent   = pTask->hParent;
 945     lpte->hInst         = pTask->hInstance;
 946     lpte->hModule       = pTask->hModule;
 947     lpte->wSS           = pTask->ss;
 948     lpte->wSP           = pTask->sp;
 949     lpte->wStackTop     = pInstData->stacktop;
 950     lpte->wStackMinimum = pInstData->stackmin;
 951     lpte->wStackBottom  = pInstData->stackbottom;
 952     lpte->wcEvents      = pTask->nEvents;
 953     lpte->hQueue        = pTask->hQueue;
 954     strncpy( lpte->szModule, pTask->module_name, 8 );
 955     lpte->szModule[8]   = '\0';
 956     lpte->wPSPOffset    = 0x100;  /*??*/
 957     lpte->hNext         = pTask->hNext;
 958     return TRUE;
 959 }
 960
 961
 962 /***********************************************************************
 963  *           TaskFindHandle   (TOOLHELP.65)
 964  */
 965 BOOL TaskFindHandle( TASKENTRY *lpte, HTASK hTask )
 966 {
 967     lpte->hNext = hTask;
 968     return TaskNext( lpte );
 969 }