loader/task.c

   1 /*
   2  * Task functions
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  */
   6
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <assert.h>
  10 #include <unistd.h>
  11
  12 #include "wine/winbase16.h"
  13 #include "ntddk.h"
  14 #include "callback.h"
  15 #include "drive.h"
  16 #include "file.h"
  17 #include "global.h"
  18 #include "instance.h"
  19 #include "miscemu.h"
  20 #include "module.h"
  21 #include "neexe.h"
  22 #include "process.h"
  23 #include "queue.h"
  24 #include "selectors.h"
  25 #include "stackframe.h"
  26 #include "task.h"
  27 #include "thread.h"
  28 #include "toolhelp.h"
  29 #include "winnt.h"
  30 #include "winsock.h"
  31 #include "syslevel.h"
  32 #include "debugtools.h"
  33 #include "services.h"
  34 #include "server.h"
  35
  36
  37 DEFAULT_DEBUG_CHANNEL(task);
  38 DECLARE_DEBUG_CHANNEL(relay);
  39 DECLARE_DEBUG_CHANNEL(toolhelp);
  40
  41   /* Min. number of thunks allocated when creating a new segment */
  42 #define MIN_THUNKS  32
  43
  44
  45 static THHOOK DefaultThhook;
  46 THHOOK *pThhook = &DefaultThhook;
  47
  48 #define hCurrentTask (pThhook->CurTDB)
  49 #define hFirstTask   (pThhook->HeadTDB)
  50 #define hLockedTask  (pThhook->LockTDB)
  51
  52 static UINT16 nTaskCount = 0;
  53
  54 static HTASK initial_task;
  55
  56 /***********************************************************************
  57  *           TASK_InstallTHHook
  58  */
  59 void TASK_InstallTHHook( THHOOK *pNewThhook )
  60 {
  61      THHOOK *pOldThhook = pThhook;
  62
  63      pThhook = pNewThhook? pNewThhook : &DefaultThhook;
  64
  65      *pThhook = *pOldThhook;
  66 }
  67
  68 /***********************************************************************
  69  *           TASK_GetNextTask
  70  */
  71 HTASK16 TASK_GetNextTask( HTASK16 hTask )
  72 {
  73     TDB* pTask = (TDB*)GlobalLock16(hTask);
  74
  75     if (pTask->hNext) return pTask->hNext;
  76     return (hFirstTask != hTask) ? hFirstTask : 0;
  77 }
  78
  79 /***********************************************************************
  80  *           TASK_LinkTask
  81  */
  82 static void TASK_LinkTask( HTASK16 hTask )
  83 {
  84     HTASK16 *prevTask;
  85     TDB *pTask;
  86
  87     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
  88     prevTask = &hFirstTask;
  89     while (*prevTask)
  90     {
  91         TDB *prevTaskPtr = (TDB *)GlobalLock16( *prevTask );
  92         if (prevTaskPtr->priority >= pTask->priority) break;
  93         prevTask = &prevTaskPtr->hNext;
  94     }
  95     pTask->hNext = *prevTask;
  96     *prevTask = hTask;
  97     nTaskCount++;
  98 }
  99
 100
 101 /***********************************************************************
 102  *           TASK_UnlinkTask
 103  */
 104 static void TASK_UnlinkTask( HTASK16 hTask )
 105 {
 106     HTASK16 *prevTask;
 107     TDB *pTask;
 108
 109     prevTask = &hFirstTask;
 110     while (*prevTask && (*prevTask != hTask))
 111     {
 112         pTask = (TDB *)GlobalLock16( *prevTask );
 113         prevTask = &pTask->hNext;
 114     }
 115     if (*prevTask)
 116     {
 117         pTask = (TDB *)GlobalLock16( *prevTask );
 118         *prevTask = pTask->hNext;
 119         pTask->hNext = 0;
 120         nTaskCount--;
 121     }
 122 }
 123
 124
 125 /***********************************************************************
 126  *           TASK_CreateThunks
 127  *
 128  * Create a thunk free-list in segment 'handle', starting from offset 'offset'
 129  * and containing 'count' entries.
 130  */
 131 static void TASK_CreateThunks( HGLOBAL16 handle, WORD offset, WORD count )
 132 {
 133     int i;
 134     WORD free;
 135     THUNKS *pThunk;
 136
 137     pThunk = (THUNKS *)((BYTE *)GlobalLock16( handle ) + offset);
 138     pThunk->next = 0;
 139     pThunk->magic = THUNK_MAGIC;
 140     pThunk->free = (int)&pThunk->thunks - (int)pThunk;
 141     free = pThunk->free;
 142     for (i = 0; i < count-1; i++)
 143     {
 144         free += 8;  /* Offset of next thunk */
 145         pThunk->thunks[4*i] = free;
 146     }
 147     pThunk->thunks[4*i] = 0;  /* Last thunk */
 148 }
 149
 150
 151 /***********************************************************************
 152  *           TASK_AllocThunk
 153  *
 154  * Allocate a thunk for MakeProcInstance().
 155  */
 156 static SEGPTR TASK_AllocThunk( HTASK16 hTask )
 157 {
 158     TDB *pTask;
 159     THUNKS *pThunk;
 160     WORD sel, base;
 161
 162     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
 163     sel = pTask->hCSAlias;
 164     pThunk = &pTask->thunks;
 165     base = (int)pThunk - (int)pTask;
 166     while (!pThunk->free)
 167     {
 168         sel = pThunk->next;
 169         if (!sel)  /* Allocate a new segment */
 170         {
 171             sel = GLOBAL_Alloc( GMEM_FIXED, sizeof(THUNKS) + (MIN_THUNKS-1)*8,
 172                                 pTask->hPDB, TRUE, FALSE, FALSE );
 173             if (!sel) return (SEGPTR)0;
 174             TASK_CreateThunks( sel, 0, MIN_THUNKS );
 175             pThunk->next = sel;
 176         }
 177         pThunk = (THUNKS *)GlobalLock16( sel );
 178         base = 0;
 179     }
 180     base += pThunk->free;
 181     pThunk->free = *(WORD *)((BYTE *)pThunk + pThunk->free);
 182     return PTR_SEG_OFF_TO_SEGPTR( sel, base );
 183 }
 184
 185
 186 /***********************************************************************
 187  *           TASK_FreeThunk
 188  *
 189  * Free a MakeProcInstance() thunk.
 190  */
 191 static BOOL TASK_FreeThunk( HTASK16 hTask, SEGPTR thunk )
 192 {
 193     TDB *pTask;
 194     THUNKS *pThunk;
 195     WORD sel, base;
 196
 197     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
 198     sel = pTask->hCSAlias;
 199     pThunk = &pTask->thunks;
 200     base = (int)pThunk - (int)pTask;
 201     while (sel && (sel != HIWORD(thunk)))
 202     {
 203         sel = pThunk->next;
 204         pThunk = (THUNKS *)GlobalLock16( sel );
 205         base = 0;
 206     }
 207     if (!sel) return FALSE;
 208     *(WORD *)((BYTE *)pThunk + LOWORD(thunk) - base) = pThunk->free;
 209     pThunk->free = LOWORD(thunk) - base;
 210     return TRUE;
 211 }
 212
 213
 214 /***********************************************************************
 215  *           TASK_Create
 216  *
 217  * NOTE: This routine might be called by a Win32 thread. Thus, we need
 218  *       to be careful to protect global data structures. We do this
 219  *       by entering the Win16Lock while linking the task into the
 220  *       global task list.
 221  */
 222 BOOL TASK_Create( NE_MODULE *pModule, UINT16 cmdShow, TEB *teb, LPCSTR cmdline, BYTE len )
 223 {
 224     HTASK16 hTask;
 225     TDB *pTask;
 226     char name[10];
 227
 228       /* Allocate the task structure */
 229
 230     hTask = GLOBAL_Alloc( GMEM_FIXED | GMEM_ZEROINIT, sizeof(TDB),
 231                           pModule->self, FALSE, FALSE, FALSE );
 232     if (!hTask) return FALSE;
 233     pTask = (TDB *)GlobalLock16( hTask );
 234
 235     /* Fill the task structure */
 236
 237     pTask->hSelf = hTask;
 238
 239     if (teb->tibflags & TEBF_WIN32)
 240     {
 241         pTask->flags        |= TDBF_WIN32;
 242         pTask->hInstance     = pModule->self;
 243         pTask->hPrevInstance = 0;
 244         /* NOTE: for 16-bit tasks, the instance handles are updated later on
 245            in NE_InitProcess */
 246     }
 247
 248     pTask->version       = pModule->expected_version;
 249     pTask->hModule       = pModule->self;
 250     pTask->hParent       = GetCurrentTask();
 251     pTask->magic         = TDB_MAGIC;
 252     pTask->nCmdShow      = cmdShow;
 253     pTask->teb           = teb;
 254     pTask->curdrive      = DRIVE_GetCurrentDrive() | 0x80;
 255     strcpy( pTask->curdir, "\\" );
 256     lstrcpynA( pTask->curdir + 1, DRIVE_GetDosCwd( DRIVE_GetCurrentDrive() ),
 257                  sizeof(pTask->curdir) - 1 );
 258
 259       /* Create the thunks block */
 260
 261     TASK_CreateThunks( hTask, (int)&pTask->thunks - (int)pTask, 7 );
 262
 263       /* Copy the module name */
 264
 265     GetModuleName16( pModule->self, name, sizeof(name) );
 266     strncpy( pTask->module_name, name, sizeof(pTask->module_name) );
 267
 268       /* Allocate a selector for the PDB */
 269
 270     pTask->hPDB = GLOBAL_CreateBlock( GMEM_FIXED, &pTask->pdb, sizeof(PDB16),
 271                                     pModule->self, FALSE, FALSE, FALSE );
 272
 273       /* Fill the PDB */
 274
 275     pTask->pdb.int20 = 0x20cd;
 276     pTask->pdb.dispatcher[0] = 0x9a;  /* ljmp */
 277     PUT_DWORD(&pTask->pdb.dispatcher[1], (DWORD)NE_GetEntryPoint(
 278            GetModuleHandle16("KERNEL"), 102 ));  /* KERNEL.102 is DOS3Call() */
 279     pTask->pdb.savedint22 = INT_GetPMHandler( 0x22 );
 280     pTask->pdb.savedint23 = INT_GetPMHandler( 0x23 );
 281     pTask->pdb.savedint24 = INT_GetPMHandler( 0x24 );
 282     pTask->pdb.fileHandlesPtr =
 283         PTR_SEG_OFF_TO_SEGPTR( GlobalHandleToSel16(pTask->hPDB),
 284                                (int)&((PDB16 *)0)->fileHandles );
 285     pTask->pdb.hFileHandles = 0;
 286     memset( pTask->pdb.fileHandles, 0xff, sizeof(pTask->pdb.fileHandles) );
 287     pTask->pdb.environment    = current_envdb.env_sel;
 288     pTask->pdb.nbFiles        = 20;
 289
 290     /* Fill the command line */
 291
 292     if (!cmdline)
 293     {
 294         cmdline = current_envdb.cmd_line;
 295         /* remove the first word (program name) */
 296         if (*cmdline == '"')
 297             if (!(cmdline = strchr( cmdline+1, '"' ))) cmdline = current_envdb.cmd_line;
 298         while (*cmdline && (*cmdline != ' ') && (*cmdline != '\t')) cmdline++;
 299         while ((*cmdline == ' ') || (*cmdline == '\t')) cmdline++;
 300         len = strlen(cmdline);
 301     }
 302     if (len >= sizeof(pTask->pdb.cmdLine)) len = sizeof(pTask->pdb.cmdLine)-1;
 303     pTask->pdb.cmdLine[0] = len;
 304     memcpy( pTask->pdb.cmdLine + 1, cmdline, len );
 305     /* pTask->pdb.cmdLine[len+1] = 0; */
 306
 307     TRACE("module='%s' cmdline='%.*s' task=%04x\n", name, len, cmdline, hTask );
 308
 309       /* Get the compatibility flags */
 310
 311     pTask->compat_flags = GetProfileIntA( "Compatibility", name, 0 );
 312
 313       /* Allocate a code segment alias for the TDB */
 314
 315     pTask->hCSAlias = GLOBAL_CreateBlock( GMEM_FIXED, (void *)pTask,
 316                                           sizeof(TDB), pTask->hPDB, TRUE,
 317                                           FALSE, FALSE );
 318
 319       /* Set the owner of the environment block */
 320
 321     FarSetOwner16( pTask->pdb.environment, pTask->hPDB );
 322
 323       /* Default DTA overwrites command line */
 324
 325     pTask->dta = PTR_SEG_OFF_TO_SEGPTR( pTask->hPDB,
 326                                 (int)&pTask->pdb.cmdLine - (int)&pTask->pdb );
 327
 328     /* Create scheduler event for 16-bit tasks */
 329
 330     if ( !(pTask->flags & TDBF_WIN32) )
 331         NtCreateEvent( &pTask->hEvent, EVENT_ALL_ACCESS, NULL, TRUE, FALSE );
 332
 333     /* Enter task handle into thread and process */
 334
 335     teb->htask16 = hTask;
 336     if (!initial_task) initial_task = hTask;
 337
 338     /* Add the task to the linked list */
 339
 340     SYSLEVEL_EnterWin16Lock();
 341     TASK_LinkTask( hTask );
 342     SYSLEVEL_LeaveWin16Lock();
 343
 344     return TRUE;
 345 }
 346
 347 /***********************************************************************
 348  *           TASK_DeleteTask
 349  */
 350 static void TASK_DeleteTask( HTASK16 hTask )
 351 {
 352     TDB *pTask;
 353     HGLOBAL16 hPDB;
 354
 355     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 356     hPDB = pTask->hPDB;
 357
 358     pTask->magic = 0xdead; /* invalidate signature */
 359
 360     /* Free the selector aliases */
 361
 362     GLOBAL_FreeBlock( pTask->hCSAlias );
 363     GLOBAL_FreeBlock( pTask->hPDB );
 364
 365     /* Free the task module */
 366
 367     FreeModule16( pTask->hModule );
 368
 369     /* Free the task structure itself */
 370
 371     GlobalFree16( hTask );
 372
 373     /* Free all memory used by this task (including the 32-bit stack, */
 374     /* the environment block and the thunk segments). */
 375
 376     GlobalFreeAll16( hPDB );
 377 }
 378
 379 /***********************************************************************
 380  *           TASK_KillTask
 381  */
 382 void TASK_KillTask( HTASK16 hTask )
 383 {
 384     TDB *pTask;
 385
 386     /* Enter the Win16Lock to protect global data structures */
 387     SYSLEVEL_EnterWin16Lock();
 388
 389     if ( !hTask ) hTask = GetCurrentTask();
 390     pTask = (TDB *)GlobalLock16( hTask );
 391     if ( !pTask )
 392     {
 393         SYSLEVEL_LeaveWin16Lock();
 394         return;
 395     }
 396
 397     TRACE("Killing task %04x\n", hTask );
 398
 399     /* Perform USER cleanup */
 400
 401     TASK_CallTaskSignalProc( USIG16_TERMINATION, hTask );
 402     PROCESS_CallUserSignalProc( USIG_PROCESS_EXIT, 0 );
 403     PROCESS_CallUserSignalProc( USIG_THREAD_EXIT, 0 );
 404     PROCESS_CallUserSignalProc( USIG_PROCESS_DESTROY, 0 );
 405
 406     if (nTaskCount <= 1)
 407     {
 408         TRACE("this is the last task, exiting\n" );
 409         ExitKernel16();
 410     }
 411
 412     /* FIXME: Hack! Send a message to the initial task so that
 413      * the GetMessage wakes up and the initial task can check whether
 414      * it is the only remaining one and terminate itself ...
 415      * The initial task should probably install hooks or something
 416      * to get informed about task termination :-/
 417      */
 418     Callout.PostAppMessage16( initial_task, WM_NULL, 0, 0 );
 419
 420     /* Remove the task from the list to be sure we never switch back to it */
 421     TASK_UnlinkTask( hTask );
 422     if( nTaskCount )
 423     {
 424         TDB* p = (TDB *)GlobalLock16( hFirstTask );
 425         while( p )
 426         {
 427             if( p->hYieldTo == hTask ) p->hYieldTo = 0;
 428             p = (TDB *)GlobalLock16( p->hNext );
 429         }
 430     }
 431
 432     pTask->nEvents = 0;
 433
 434     if ( hLockedTask == hTask )
 435         hLockedTask = 0;
 436
 437     TASK_DeleteTask( hTask );
 438
 439     /* When deleting the current task ... */
 440     if ( hTask == hCurrentTask )
 441     {
 442         DWORD lockCount;
 443
 444         /* ... schedule another one ... */
 445         TASK_Reschedule();
 446
 447         /* ... and completely release the Win16Lock, just in case. */
 448         ReleaseThunkLock( &lockCount );
 449
 450         return;
 451     }
 452
 453     SYSLEVEL_LeaveWin16Lock();
 454 }
 455
 456 /***********************************************************************
 457  *           TASK_Reschedule
 458  *
 459  * This is where all the magic of task-switching happens!
 460  *
 461  * 16-bit Windows performs non-preemptive (cooperative) multitasking.
 462  * This means that each 16-bit task runs until it voluntarily yields
 463  * control, at which point the scheduler gets active and selects the
 464  * next task to run.
 465  *
 466  * In Wine, all processes, even 16-bit ones, are scheduled preemptively
 467  * by the standard scheduler of the underlying OS.  As many 16-bit apps
 468  * *rely* on the behaviour of the Windows scheduler, however, we have
 469  * to simulate that behaviour.
 470  *
 471  * This is achieved as follows: every 16-bit task is at time (except
 472  * during task creation and deletion) in one of two states: either it
 473  * is the one currently running, then the global variable hCurrentTask
 474  * contains its task handle, or it is not currently running, then it
 475  * is blocked on a special scheduler event, a global handle which
 476  * is stored in the task struct.
 477  *
 478  * When the current task yields control, this routine gets called. Its
 479  * purpose is to determine the next task to be active, signal the
 480  * scheduler event of that task, and then put the current task to sleep
 481  * waiting for *its* scheduler event to get signalled again.
 482  *
 483  * This routine can get called in a few other special situations as well:
 484  *
 485  * - On creation of a 16-bit task, the Unix process executing the task
 486  *   calls TASK_Reschedule once it has completed its initialization.
 487  *   At this point, the task needs to be blocked until its scheduler
 488  *   event is signalled the first time (this will be done by the parent
 489  *   process to get the task up and running).
 490  *
 491  * - When the task currently running terminates itself, this routine gets
 492  *   called and has to schedule another task, *without* blocking the
 493  *   terminating task.
 494  *
 495  * - When a 32-bit thread posts an event for a 16-bit task, it might be
 496  *   the case that *no* 16-bit task is currently running.  In this case
 497  *   the task that has now an event pending is to be scheduled.
 498  *
 499  */
 500 void TASK_Reschedule(void)
 501 {
 502     TDB *pOldTask = NULL, *pNewTask = NULL;
 503     HTASK16 hOldTask = 0, hNewTask = 0;
 504     enum { MODE_YIELD, MODE_SLEEP, MODE_WAKEUP } mode;
 505     DWORD lockCount;
 506
 507     SYSLEVEL_EnterWin16Lock();
 508
 509     /* Check what we need to do */
 510     hOldTask = GetCurrentTask();
 511     pOldTask = (TDB *)GlobalLock16( hOldTask );
 512     TRACE( "entered with hCurrentTask %04x by hTask %04x (pid %ld)\n",
 513            hCurrentTask, hOldTask, (long) getpid() );
 514
 515     if ( pOldTask && THREAD_IsWin16( NtCurrentTeb() ) )
 516     {
 517         /* We are called by an active (non-deleted) 16-bit task */
 518
 519         /* If we don't even have a current task, or else the current
 520            task has yielded, we'll need to schedule a new task and
 521            (possibly) put the calling task to sleep.  Otherwise, we
 522            only block the caller. */
 523
 524         if ( !hCurrentTask || hCurrentTask == hOldTask )
 525             mode = MODE_YIELD;
 526         else
 527             mode = MODE_SLEEP;
 528     }
 529     else
 530     {
 531         /* We are called by a deleted 16-bit task or a 32-bit thread */
 532
 533         /* The only situation where we need to do something is if we
 534            now do not have a current task.  Then, we'll need to wake up
 535            some task that has events pending. */
 536
 537         if ( !hCurrentTask || hCurrentTask == hOldTask )
 538             mode = MODE_WAKEUP;
 539         else
 540         {
 541             /* nothing to do */
 542             SYSLEVEL_LeaveWin16Lock();
 543             return;
 544         }
 545     }
 546
 547     /* Find a task to yield to: check for DirectedYield() */
 548     if ( mode == MODE_YIELD && pOldTask && pOldTask->hYieldTo )
 549     {
 550         hNewTask = pOldTask->hYieldTo;
 551         pNewTask = (TDB *)GlobalLock16( hNewTask );
 552         if( !pNewTask || !pNewTask->nEvents) hNewTask = 0;
 553         pOldTask->hYieldTo = 0;
 554     }
 555
 556     /* Find a task to yield to: check for pending events */
 557     if ( (mode == MODE_YIELD || mode == MODE_WAKEUP) && !hNewTask )
 558     {
 559         hNewTask = hFirstTask;
 560         while (hNewTask)
 561         {
 562             pNewTask = (TDB *)GlobalLock16( hNewTask );
 563
 564             TRACE( "\ttask = %04x, events = %i\n", hNewTask, pNewTask->nEvents );
 565
 566             if (pNewTask->nEvents) break;
 567             hNewTask = pNewTask->hNext;
 568         }
 569         if (hLockedTask && (hNewTask != hLockedTask)) hNewTask = 0;
 570     }
 571
 572     /* If we are still the task with highest priority, just return ... */
 573     if ( mode == MODE_YIELD && hNewTask && hNewTask == hCurrentTask )
 574     {
 575         TRACE("returning to the current task (%04x)\n", hCurrentTask );
 576         SYSLEVEL_LeaveWin16Lock();
 577
 578         /* Allow Win32 threads to thunk down even while a Win16 task is
 579            in a tight PeekMessage() or Yield() loop ... */
 580         ReleaseThunkLock( &lockCount );
 581         RestoreThunkLock( lockCount );
 582         return;
 583     }
 584
 585     /* If no task to yield to found, suspend 16-bit scheduler ... */
 586     if ( mode == MODE_YIELD && !hNewTask )
 587     {
 588         TRACE("No currently active task\n");
 589         hCurrentTask = 0;
 590     }
 591
 592     /* If we found a task to wake up, do it ... */
 593     if ( (mode == MODE_YIELD || mode == MODE_WAKEUP) && hNewTask )
 594     {
 595         TRACE("Switching to task %04x (%.8s)\n",
 596                       hNewTask, pNewTask->module_name );
 597
 598         pNewTask->priority++;
 599         TASK_UnlinkTask( hNewTask );
 600         TASK_LinkTask( hNewTask );
 601         pNewTask->priority--;
 602
 603         hCurrentTask = hNewTask;
 604         NtSetEvent( pNewTask->hEvent, NULL );
 605
 606         /* This is set just in case some app reads it ... */
 607         pNewTask->ss_sp = pNewTask->teb->cur_stack;
 608     }
 609
 610     /* If we need to put the current task to sleep, do it ... */
 611     if ( (mode == MODE_YIELD || mode == MODE_SLEEP) && hOldTask != hCurrentTask )
 612     {
 613         NtResetEvent( pOldTask->hEvent, NULL );
 614
 615         ReleaseThunkLock( &lockCount );
 616         SYSLEVEL_CheckNotLevel( 1 );
 617         WaitForSingleObject( pOldTask->hEvent, INFINITE );
 618         RestoreThunkLock( lockCount );
 619     }
 620
 621     SYSLEVEL_LeaveWin16Lock();
 622 }
 623
 624 /***********************************************************************
 625  *           InitTask  (KERNEL.91)
 626  *
 627  * Called by the application startup code.
 628  */
 629 void WINAPI InitTask16( CONTEXT86 *context )
 630 {
 631     TDB *pTask;
 632     INSTANCEDATA *pinstance;
 633     SEGPTR ptr;
 634
 635     context->Eax = 0;
 636     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
 637
 638     /* Note: we need to trust that BX/CX contain the stack/heap sizes,
 639        as some apps, notably Visual Basic apps, *modify* the heap/stack
 640        size of the instance data segment before calling InitTask() */
 641
 642     /* Initialize the INSTANCEDATA structure */
 643     pinstance = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN(CURRENT_DS, 0);
 644     pinstance->stackmin    = OFFSETOF( pTask->teb->cur_stack ) + sizeof( STACK16FRAME );
 645     pinstance->stackbottom = pinstance->stackmin; /* yup, that's right. Confused me too. */
 646     pinstance->stacktop    = ( pinstance->stackmin > LOWORD(context->Ebx) ?
 647                                pinstance->stackmin - LOWORD(context->Ebx) : 0 ) + 150;
 648
 649     /* Initialize the local heap */
 650     if (LOWORD(context->Ecx))
 651         LocalInit16( GlobalHandleToSel16(pTask->hInstance), 0, LOWORD(context->Ecx) );
 652
 653     /* Initialize implicitly loaded DLLs */
 654     NE_InitializeDLLs( pTask->hModule );
 655     NE_DllProcessAttach( pTask->hModule );
 656
 657     /* Registers on return are:
 658      * ax     1 if OK, 0 on error
 659      * cx     stack limit in bytes
 660      * dx     cmdShow parameter
 661      * si     instance handle of the previous instance
 662      * di     instance handle of the new task
 663      * es:bx  pointer to command line inside PSP
 664      *
 665      * 0 (=%bp) is pushed on the stack
 666      */
 667     ptr = stack16_push( sizeof(WORD) );
 668     *(WORD *)PTR_SEG_TO_LIN(ptr) = 0;
 669     context->Esp -= 2;
 670
 671     context->Eax = 1;
 672
 673     if (!pTask->pdb.cmdLine[0]) context->Ebx = 0x80;
 674     else
 675     {
 676         LPBYTE p = &pTask->pdb.cmdLine[1];
 677         while ((*p == ' ') || (*p == '\t')) p++;
 678         context->Ebx = 0x80 + (p - pTask->pdb.cmdLine);
 679     }
 680     context->Ecx   = pinstance->stacktop;
 681     context->Edx   = pTask->nCmdShow;
 682     context->Esi   = (DWORD)pTask->hPrevInstance;
 683     context->Edi   = (DWORD)pTask->hInstance;
 684     context->SegEs = (WORD)pTask->hPDB;
 685 }
 686
 687
 688 /***********************************************************************
 689  *           WaitEvent  (KERNEL.30)
 690  */
 691 BOOL16 WINAPI WaitEvent16( HTASK16 hTask )
 692 {
 693     TDB *pTask;
 694
 695     if (!hTask) hTask = GetCurrentTask();
 696     pTask = (TDB *)GlobalLock16( hTask );
 697
 698     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 699     {
 700         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 701         return TRUE;
 702     }
 703
 704     if (pTask->nEvents > 0)
 705     {
 706         pTask->nEvents--;
 707         return FALSE;
 708     }
 709     TASK_Reschedule();
 710
 711     /* When we get back here, we have an event */
 712
 713     if (pTask->nEvents > 0) pTask->nEvents--;
 714     return TRUE;
 715 }
 716
 717
 718 /***********************************************************************
 719  *           PostEvent  (KERNEL.31)
 720  */
 721 void WINAPI PostEvent16( HTASK16 hTask )
 722 {
 723     TDB *pTask;
 724
 725     if (!hTask) hTask = GetCurrentTask();
 726     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 727
 728     if ( !THREAD_IsWin16( pTask->teb ) )
 729     {
 730         FIXME("called for Win32 thread (%04x)!\n", pTask->teb->teb_sel );
 731         return;
 732     }
 733
 734     pTask->nEvents++;
 735
 736     /* If we are a 32-bit task, we might need to wake up the 16-bit scheduler */
 737     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 738         TASK_Reschedule();
 739 }
 740
 741
 742 /***********************************************************************
 743  *           SetPriority  (KERNEL.32)
 744  */
 745 void WINAPI SetPriority16( HTASK16 hTask, INT16 delta )
 746 {
 747     TDB *pTask;
 748     INT16 newpriority;
 749
 750     if (!hTask) hTask = GetCurrentTask();
 751     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 752     newpriority = pTask->priority + delta;
 753     if (newpriority < -32) newpriority = -32;
 754     else if (newpriority > 15) newpriority = 15;
 755
 756     pTask->priority = newpriority + 1;
 757     TASK_UnlinkTask( hTask );
 758     TASK_LinkTask( hTask );
 759     pTask->priority--;
 760 }
 761
 762
 763 /***********************************************************************
 764  *           LockCurrentTask  (KERNEL.33)
 765  */
 766 HTASK16 WINAPI LockCurrentTask16( BOOL16 bLock )
 767 {
 768     if (bLock) hLockedTask = GetCurrentTask();
 769     else hLockedTask = 0;
 770     return hLockedTask;
 771 }
 772
 773
 774 /***********************************************************************
 775  *           IsTaskLocked  (KERNEL.122)
 776  */
 777 HTASK16 WINAPI IsTaskLocked16(void)
 778 {
 779     return hLockedTask;
 780 }
 781
 782
 783 /***********************************************************************
 784  *           OldYield  (KERNEL.117)
 785  */
 786 void WINAPI OldYield16(void)
 787 {
 788     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 789
 790     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 791     {
 792         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 793         return;
 794     }
 795
 796     if (pCurTask) pCurTask->nEvents++;  /* Make sure we get back here */
 797     TASK_Reschedule();
 798     if (pCurTask) pCurTask->nEvents--;
 799 }
 800
 801 /***********************************************************************
 802  *           WIN32_OldYield16  (KERNEL.447)
 803  */
 804 void WINAPI WIN32_OldYield16(void)
 805 {
 806    DWORD count;
 807
 808    ReleaseThunkLock(&count);
 809    RestoreThunkLock(count);
 810 }
 811
 812 /***********************************************************************
 813  *           DirectedYield  (KERNEL.150)
 814  */
 815 void WINAPI DirectedYield16( HTASK16 hTask )
 816 {
 817     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 818
 819     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 820     {
 821         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 822         return;
 823     }
 824
 825     TRACE("%04x: DirectedYield(%04x)\n", pCurTask->hSelf, hTask );
 826
 827     pCurTask->hYieldTo = hTask;
 828     OldYield16();
 829
 830     TRACE("%04x: back from DirectedYield(%04x)\n", pCurTask->hSelf, hTask );
 831 }
 832
 833 /***********************************************************************
 834  *           Yield16  (KERNEL.29)
 835  */
 836 void WINAPI Yield16(void)
 837 {
 838     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 839
 840     if (pCurTask) pCurTask->hYieldTo = 0;
 841     if (pCurTask && pCurTask->hQueue) Callout.UserYield16();
 842     else OldYield16();
 843 }
 844
 845 /***********************************************************************
 846  *           KERNEL_490  (KERNEL.490)
 847  */
 848 HTASK16 WINAPI KERNEL_490( HTASK16 someTask )
 849 {
 850     if ( !someTask ) return 0;
 851
 852     FIXME("(%04x): stub\n", someTask );
 853     return 0;
 854 }
 855
 856 /***********************************************************************
 857  *           MakeProcInstance16  (KERNEL.51)
 858  */
 859 FARPROC16 WINAPI MakeProcInstance16( FARPROC16 func, HANDLE16 hInstance )
 860 {
 861     BYTE *thunk,*lfunc;
 862     SEGPTR thunkaddr;
 863     WORD hInstanceSelector;
 864
 865     hInstanceSelector = GlobalHandleToSel16(hInstance);
 866
 867     TRACE("(%08lx, %04x);\n", (DWORD)func, hInstance);
 868
 869     if (!HIWORD(func)) {
 870       /* Win95 actually protects via SEH, but this is better for debugging */
 871       WARN("Ouch ! Called with invalid func 0x%08lx !\n", (DWORD)func);
 872       return (FARPROC16)0;
 873     }
 874
 875     if (hInstance)
 876     {
 877         if ( (!(hInstance & 4)) ||
 878              ((hInstance != 0xffff) && IS_SELECTOR_FREE(hInstance|7)) )
 879         {
 880             WARN("Invalid hInstance (%04x) passed to MakeProcInstance !\n",
 881                 hInstance);
 882             return 0;
 883         }
 884     }
 885
 886     if ( (GlobalHandleToSel16(CURRENT_DS) != hInstanceSelector)
 887       && (hInstance != 0)
 888       && (hInstance != 0xffff) )
 889     {
 890         /* calling MPI with a foreign DSEG is invalid ! */
 891         WARN("Problem with hInstance? Got %04x, using %04x instead\n",
 892                    hInstance,CURRENT_DS);
 893     }
 894
 895     /* Always use the DSEG that MPI was entered with.
 896      * We used to set hInstance to GetTaskDS16(), but this should be wrong
 897      * as CURRENT_DS provides the DSEG value we need.
 898      * ("calling" DS, *not* "task" DS !) */
 899     hInstanceSelector = CURRENT_DS;
 900     hInstance = GlobalHandle16(hInstanceSelector);
 901
 902     /* no thunking for DLLs */
 903     if (NE_GetPtr(FarGetOwner16(hInstance))->flags & NE_FFLAGS_LIBMODULE)
 904         return func;
 905
 906     thunkaddr = TASK_AllocThunk( GetCurrentTask() );
 907     if (!thunkaddr) return (FARPROC16)0;
 908     thunk = PTR_SEG_TO_LIN( thunkaddr );
 909     lfunc = PTR_SEG_TO_LIN( func );
 910
 911     TRACE("(%08lx,%04x): got thunk %08lx\n",
 912           (DWORD)func, hInstance, (DWORD)thunkaddr );
 913     if (((lfunc[0]==0x8c) && (lfunc[1]==0xd8)) || /* movw %ds, %ax */
 914         ((lfunc[0]==0x1e) && (lfunc[1]==0x58))    /* pushw %ds, popw %ax */
 915     ) {
 916         WARN("This was the (in)famous \"thunk useless\" warning. We thought we have to overwrite with nop;nop;, but this isn't true.\n");
 917     }
 918
 919     *thunk++ = 0xb8;    /* movw instance, %ax */
 920     *thunk++ = (BYTE)(hInstanceSelector & 0xff);
 921     *thunk++ = (BYTE)(hInstanceSelector >> 8);
 922     *thunk++ = 0xea;    /* ljmp func */
 923     *(DWORD *)thunk = (DWORD)func;
 924     return (FARPROC16)thunkaddr;
 925     /* CX reg indicates if thunkaddr != NULL, implement if needed */
 926 }
 927
 928
 929 /***********************************************************************
 930  *           FreeProcInstance16  (KERNEL.52)
 931  */
 932 void WINAPI FreeProcInstance16( FARPROC16 func )
 933 {
 934     TRACE("(%08lx)\n", (DWORD)func );
 935     TASK_FreeThunk( GetCurrentTask(), (SEGPTR)func );
 936 }
 937
 938 /**********************************************************************
 939  *          TASK_GetCodeSegment
 940  *
 941  * Helper function for GetCodeHandle/GetCodeInfo: Retrieve the module
 942  * and logical segment number of a given code segment.
 943  *
 944  * 'proc' either *is* already a pair of module handle and segment number,
 945  * in which case there's nothing to do.  Otherwise, it is a pointer to
 946  * a function, and we need to retrieve the code segment.  If the pointer
 947  * happens to point to a thunk, we'll retrieve info about the code segment
 948  * where the function pointed to by the thunk resides, not the thunk itself.
 949  *
 950  * FIXME: if 'proc' is a SNOOP16 return stub, we should retrieve info about
 951  *        the function the snoop code will return to ...
 952  *
 953  */
 954 static BOOL TASK_GetCodeSegment( FARPROC16 proc, NE_MODULE **ppModule,
 955                                  SEGTABLEENTRY **ppSeg, int *pSegNr )
 956 {
 957     NE_MODULE *pModule = NULL;
 958     SEGTABLEENTRY *pSeg = NULL;
 959     int segNr;
 960
 961     /* Try pair of module handle / segment number */
 962     pModule = (NE_MODULE *) GlobalLock16( HIWORD( proc ) );
 963     if ( pModule && pModule->magic == IMAGE_OS2_SIGNATURE )
 964     {
 965         segNr = LOWORD( proc );
 966         if ( segNr && segNr <= pModule->seg_count )
 967             pSeg = NE_SEG_TABLE( pModule ) + segNr-1;
 968     }
 969
 970     /* Try thunk or function */
 971     else
 972     {
 973         BYTE *thunk = (BYTE *)PTR_SEG_TO_LIN( proc );
 974         WORD selector;
 975
 976         if ((thunk[0] == 0xb8) && (thunk[3] == 0xea))
 977             selector = thunk[6] + (thunk[7] << 8);
 978         else
 979             selector = HIWORD( proc );
 980
 981         pModule = NE_GetPtr( GlobalHandle16( selector ) );
 982         pSeg = pModule? NE_SEG_TABLE( pModule ) : NULL;
 983
 984         if ( pModule )
 985             for ( segNr = 1; segNr <= pModule->seg_count; segNr++, pSeg++ )
 986                 if ( GlobalHandleToSel16(pSeg->hSeg) == selector )
 987                     break;
 988
 989         if ( pModule && segNr > pModule->seg_count )
 990             pSeg = NULL;
 991     }
 992
 993     /* Abort if segment not found */
 994
 995     if ( !pModule || !pSeg )
 996         return FALSE;
 997
 998     /* Return segment data */
 999
1000     if ( ppModule ) *ppModule = pModule;
1001     if ( ppSeg    ) *ppSeg    = pSeg;
1002     if ( pSegNr   ) *pSegNr   = segNr;
1003
1004     return TRUE;
1005 }
1006
1007 /**********************************************************************
1008  *          GetCodeHandle    (KERNEL.93)
1009  */
1010 HANDLE16 WINAPI GetCodeHandle16( FARPROC16 proc )
1011 {
1012     SEGTABLEENTRY *pSeg;
1013
1014     if ( !TASK_GetCodeSegment( proc, NULL, &pSeg, NULL ) )
1015         return (HANDLE16)0;
1016
1017     return pSeg->hSeg;
1018 }
1019
1020 /**********************************************************************
1021  *          GetCodeInfo    (KERNEL.104)
1022  */
1023 BOOL16 WINAPI GetCodeInfo16( FARPROC16 proc, SEGINFO *segInfo )
1024 {
1025     NE_MODULE *pModule;
1026     SEGTABLEENTRY *pSeg;
1027     int segNr;
1028
1029     if ( !TASK_GetCodeSegment( proc, &pModule, &pSeg, &segNr ) )
1030         return FALSE;
1031
1032     /* Fill in segment information */
1033
1034     segInfo->offSegment = pSeg->filepos;
1035     segInfo->cbSegment  = pSeg->size;
1036     segInfo->flags      = pSeg->flags;
1037     segInfo->cbAlloc    = pSeg->minsize;
1038     segInfo->h          = pSeg->hSeg;
1039     segInfo->alignShift = pModule->alignment;
1040
1041     if ( segNr == pModule->dgroup )
1042         segInfo->cbAlloc += pModule->heap_size + pModule->stack_size;
1043
1044     /* Return module handle in %es */
1045
1046     CURRENT_STACK16->es = GlobalHandleToSel16( pModule->self );
1047
1048     return TRUE;
1049 }
1050
1051
1052 /**********************************************************************
1053  *          DefineHandleTable16    (KERNEL.94)
1054  */
1055 BOOL16 WINAPI DefineHandleTable16( WORD wOffset )
1056 {
1057     FIXME("(%04x): stub ?\n", wOffset);
1058     return TRUE;
1059 }
1060
1061
1062 /***********************************************************************
1063  *           SetTaskQueue  (KERNEL.34)
1064  */
1065 HQUEUE16 WINAPI SetTaskQueue16( HTASK16 hTask, HQUEUE16 hQueue )
1066 {
1067     HQUEUE16 hPrev;
1068     TDB *pTask;
1069
1070     if (!hTask) hTask = GetCurrentTask();
1071     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
1072
1073     hPrev = pTask->hQueue;
1074     pTask->hQueue = hQueue;
1075
1076     return hPrev;
1077 }
1078
1079
1080 /***********************************************************************
1081  *           GetTaskQueue  (KERNEL.35)
1082  */
1083 HQUEUE16 WINAPI GetTaskQueue16( HTASK16 hTask )
1084 {
1085     TDB *pTask;
1086
1087     if (!hTask) hTask = GetCurrentTask();
1088     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
1089     return pTask->hQueue;
1090 }
1091
1092 /***********************************************************************
1093  *           SetThreadQueue  (KERNEL.463)
1094  */
1095 HQUEUE16 WINAPI SetThreadQueue16( DWORD thread, HQUEUE16 hQueue )
1096 {
1097     TEB *teb = thread? THREAD_IdToTEB( thread ) : NtCurrentTeb();
1098     HQUEUE16 oldQueue = teb? teb->queue : 0;
1099
1100     if ( teb )
1101     {
1102         teb->queue = hQueue;
1103
1104         if ( GetTaskQueue16( teb->htask16 ) == oldQueue )
1105             SetTaskQueue16( teb->htask16, hQueue );
1106     }
1107
1108     return oldQueue;
1109 }
1110
1111 /***********************************************************************
1112  *           GetThreadQueue  (KERNEL.464)
1113  */
1114 HQUEUE16 WINAPI GetThreadQueue16( DWORD thread )
1115 {
1116     TEB *teb = NULL;
1117     if ( !thread )
1118         teb = NtCurrentTeb();
1119     else if ( HIWORD(thread) )
1120         teb = THREAD_IdToTEB( thread );
1121     else if ( IsTask16( (HTASK16)thread ) )
1122         teb = ((TDB *)GlobalLock16( (HANDLE16)thread ))->teb;
1123
1124     return (HQUEUE16)(teb? teb->queue : 0);
1125 }
1126
1127 /***********************************************************************
1128  *           SetFastQueue  (KERNEL.624)
1129  */
1130 VOID WINAPI SetFastQueue16( DWORD thread, HANDLE hQueue )
1131 {
1132     TEB *teb = NULL;
1133     if ( !thread )
1134         teb = NtCurrentTeb();
1135     else if ( HIWORD(thread) )
1136         teb = THREAD_IdToTEB( thread );
1137     else if ( IsTask16( (HTASK16)thread ) )
1138         teb = ((TDB *)GlobalLock16( (HANDLE16)thread ))->teb;
1139
1140     if ( teb ) teb->queue = (HQUEUE16) hQueue;
1141 }
1142
1143 /***********************************************************************
1144  *           GetFastQueue  (KERNEL.625)
1145  */
1146 HANDLE WINAPI GetFastQueue16( void )
1147 {
1148     TEB *teb = NtCurrentTeb();
1149     if (!teb) return 0;
1150
1151     if (!teb->queue)
1152         Callout.InitThreadInput16( 0, THREAD_IsWin16(teb)? 4 : 5 );
1153
1154     if (!teb->queue)
1155         FIXME("(): should initialize thread-local queue, expect failure!\n" );
1156
1157     return (HANDLE)teb->queue;
1158 }
1159
1160 /***********************************************************************
1161  *           SwitchStackTo   (KERNEL.108)
1162  */
1163 void WINAPI SwitchStackTo16( WORD seg, WORD ptr, WORD top )
1164 {
1165     TDB *pTask;
1166     STACK16FRAME *oldFrame, *newFrame;
1167     INSTANCEDATA *pData;
1168     UINT16 copySize;
1169
1170     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
1171     if (!(pData = (INSTANCEDATA *)GlobalLock16( seg ))) return;
1172     TRACE("old=%04x:%04x new=%04x:%04x\n",
1173           SELECTOROF( pTask->teb->cur_stack ),
1174           OFFSETOF( pTask->teb->cur_stack ), seg, ptr );
1175
1176     /* Save the old stack */
1177
1178     oldFrame = THREAD_STACK16( pTask->teb );
1179     /* pop frame + args and push bp */
1180     pData->old_ss_sp   = pTask->teb->cur_stack + sizeof(STACK16FRAME)
1181                            + 2 * sizeof(WORD);
1182     *(WORD *)PTR_SEG_TO_LIN(pData->old_ss_sp) = oldFrame->bp;
1183     pData->stacktop    = top;
1184     pData->stackmin    = ptr;
1185     pData->stackbottom = ptr;
1186
1187     /* Switch to the new stack */
1188
1189     /* Note: we need to take the 3 arguments into account; otherwise,
1190      * the stack will underflow upon return from this function.
1191      */
1192     copySize = oldFrame->bp - OFFSETOF(pData->old_ss_sp);
1193     copySize += 3 * sizeof(WORD) + sizeof(STACK16FRAME);
1194     pTask->teb->cur_stack = PTR_SEG_OFF_TO_SEGPTR( seg, ptr - copySize );
1195     newFrame = THREAD_STACK16( pTask->teb );
1196
1197     /* Copy the stack frame and the local variables to the new stack */
1198
1199     memmove( newFrame, oldFrame, copySize );
1200     newFrame->bp = ptr;
1201     *(WORD *)PTR_SEG_OFF_TO_LIN( seg, ptr ) = 0;  /* clear previous bp */
1202 }
1203
1204
1205 /***********************************************************************
1206  *           SwitchStackBack   (KERNEL.109)
1207  */
1208 void WINAPI SwitchStackBack16( CONTEXT86 *context )
1209 {
1210     STACK16FRAME *oldFrame, *newFrame;
1211     INSTANCEDATA *pData;
1212
1213     if (!(pData = (INSTANCEDATA *)GlobalLock16(SELECTOROF(NtCurrentTeb()->cur_stack))))
1214         return;
1215     if (!pData->old_ss_sp)
1216     {
1217         WARN("No previous SwitchStackTo\n" );
1218         return;
1219     }
1220     TRACE("restoring stack %04x:%04x\n",
1221           SELECTOROF(pData->old_ss_sp), OFFSETOF(pData->old_ss_sp) );
1222
1223     oldFrame = CURRENT_STACK16;
1224
1225     /* Pop bp from the previous stack */
1226
1227     BP_reg(context) = *(WORD *)PTR_SEG_TO_LIN(pData->old_ss_sp);
1228     pData->old_ss_sp += sizeof(WORD);
1229
1230     /* Switch back to the old stack */
1231
1232     NtCurrentTeb()->cur_stack = pData->old_ss_sp - sizeof(STACK16FRAME);
1233     context->SegSs = SELECTOROF(pData->old_ss_sp);
1234     context->Esp   = OFFSETOF(pData->old_ss_sp) - sizeof(DWORD); /*ret addr*/
1235     pData->old_ss_sp = 0;
1236
1237     /* Build a stack frame for the return */
1238
1239     newFrame = CURRENT_STACK16;
1240     newFrame->frame32     = oldFrame->frame32;
1241     newFrame->module_cs   = oldFrame->module_cs;
1242     newFrame->callfrom_ip = oldFrame->callfrom_ip;
1243     newFrame->entry_ip    = oldFrame->entry_ip;
1244 }
1245
1246
1247 /***********************************************************************
1248  *           GetTaskQueueDS16  (KERNEL.118)
1249  */
1250 void WINAPI GetTaskQueueDS16(void)
1251 {
1252     CURRENT_STACK16->ds = GlobalHandleToSel16( GetTaskQueue16(0) );
1253 }
1254
1255
1256 /***********************************************************************
1257  *           GetTaskQueueES16  (KERNEL.119)
1258  */
1259 void WINAPI GetTaskQueueES16(void)
1260 {
1261     CURRENT_STACK16->es = GlobalHandleToSel16( GetTaskQueue16(0) );
1262 }
1263
1264
1265 /***********************************************************************
1266  *           GetCurrentTask   (KERNEL.36)
1267  */
1268 HTASK16 WINAPI GetCurrentTask(void)
1269 {
1270     return NtCurrentTeb()->htask16;
1271 }
1272
1273 DWORD WINAPI WIN16_GetCurrentTask(void)
1274 {
1275     /* This is the version used by relay code; the first task is */
1276     /* returned in the high word of the result */
1277     return MAKELONG( GetCurrentTask(), hFirstTask );
1278 }
1279
1280
1281 /***********************************************************************
1282  *           GetCurrentPDB   (KERNEL.37)
1283  *
1284  * UNDOC: returns PSP of KERNEL in high word
1285  */
1286 DWORD WINAPI GetCurrentPDB16(void)
1287 {
1288     TDB *pTask;
1289
1290     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1291     return MAKELONG(pTask->hPDB, 0); /* FIXME */
1292 }
1293
1294
1295 /***********************************************************************
1296  *           GetCurPID16   (KERNEL.157)
1297  */
1298 DWORD WINAPI GetCurPID16( DWORD unused )
1299 {
1300     return 0;
1301 }
1302
1303
1304 /***********************************************************************
1305  *           GetInstanceData   (KERNEL.54)
1306  */
1307 INT16 WINAPI GetInstanceData16( HINSTANCE16 instance, WORD buffer, INT16 len )
1308 {
1309     char *ptr = (char *)GlobalLock16( instance );
1310     if (!ptr || !len) return 0;
1311     if ((int)buffer + len >= 0x10000) len = 0x10000 - buffer;
1312     memcpy( (char *)GlobalLock16(CURRENT_DS) + buffer, ptr + buffer, len );
1313     return len;
1314 }
1315
1316
1317 /***********************************************************************
1318  *           GetExeVersion   (KERNEL.105)
1319  */
1320 WORD WINAPI GetExeVersion16(void)
1321 {
1322     TDB *pTask;
1323
1324     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1325     return pTask->version;
1326 }
1327
1328
1329 /***********************************************************************
1330  *           SetErrorMode16   (KERNEL.107)
1331  */
1332 UINT16 WINAPI SetErrorMode16( UINT16 mode )
1333 {
1334     TDB *pTask;
1335     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1336     pTask->error_mode = mode;
1337     return SetErrorMode( mode );
1338 }
1339
1340
1341 /***********************************************************************
1342  *           GetDOSEnvironment   (KERNEL.131)
1343  */
1344 SEGPTR WINAPI GetDOSEnvironment16(void)
1345 {
1346     TDB *pTask;
1347
1348     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1349     return PTR_SEG_OFF_TO_SEGPTR( pTask->pdb.environment, 0 );
1350 }
1351
1352
1353 /***********************************************************************
1354  *           GetNumTasks   (KERNEL.152)
1355  */
1356 UINT16 WINAPI GetNumTasks16(void)
1357 {
1358     return nTaskCount;
1359 }
1360
1361
1362 /***********************************************************************
1363  *           GetTaskDS   (KERNEL.155)
1364  *
1365  * Note: this function apparently returns a DWORD with LOWORD == HIWORD.
1366  * I don't think we need to bother with this.
1367  */
1368 HINSTANCE16 WINAPI GetTaskDS16(void)
1369 {
1370     TDB *pTask;
1371
1372     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1373     return GlobalHandleToSel16(pTask->hInstance);
1374 }
1375
1376 /***********************************************************************
1377  *           GetDummyModuleHandleDS   (KERNEL.602)
1378  */
1379 WORD WINAPI GetDummyModuleHandleDS16(void)
1380 {
1381     TDB *pTask;
1382     WORD selector;
1383
1384     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1385     if (!(pTask->flags & TDBF_WIN32)) return 0;
1386     selector = GlobalHandleToSel16( pTask->hModule );
1387     CURRENT_DS = selector;
1388     return selector;
1389 }
1390
1391 /***********************************************************************
1392  *           IsTask   (KERNEL.320)
1393  */
1394 BOOL16 WINAPI IsTask16( HTASK16 hTask )
1395 {
1396     TDB *pTask;
1397
1398     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return FALSE;
1399     if (GlobalSize16( hTask ) < sizeof(TDB)) return FALSE;
1400     return (pTask->magic == TDB_MAGIC);
1401 }
1402
1403
1404 /***********************************************************************
1405  *           IsWinOldApTask16   (KERNEL.158)
1406  */
1407 BOOL16 WINAPI IsWinOldApTask16( HTASK16 hTask )
1408 {
1409     /* should return bit 0 of byte 0x48 in PSP */
1410     return FALSE;
1411 }
1412
1413 /***********************************************************************
1414  *           SetTaskSignalProc   (KERNEL.38)
1415  */
1416 FARPROC16 WINAPI SetTaskSignalProc( HTASK16 hTask, FARPROC16 proc )
1417 {
1418     TDB *pTask;
1419     FARPROC16 oldProc;
1420
1421     if (!hTask) hTask = GetCurrentTask();
1422     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return NULL;
1423     oldProc = pTask->userhandler;
1424     pTask->userhandler = proc;
1425     return oldProc;
1426 }
1427
1428 /***********************************************************************
1429  *           TASK_CallTaskSignalProc
1430  */
1431 /* ### start build ### */
1432 extern WORD CALLBACK TASK_CallTo16_word_wwwww(FARPROC16,WORD,WORD,WORD,WORD,WORD);
1433 /* ### stop build ### */
1434 void TASK_CallTaskSignalProc( UINT16 uCode, HANDLE16 hTaskOrModule )
1435 {
1436     TDB *pTask = (TDB *)GlobalLock16( GetCurrentTask() );
1437     if ( !pTask || !pTask->userhandler ) return;
1438
1439     TASK_CallTo16_word_wwwww( pTask->userhandler,
1440                               hTaskOrModule, uCode, 0,
1441                               pTask->hInstance, pTask->hQueue );
1442 }
1443
1444 /***********************************************************************
1445  *           SetSigHandler   (KERNEL.140)
1446  */
1447 WORD WINAPI SetSigHandler16( FARPROC16 newhandler, FARPROC16* oldhandler,
1448                            UINT16 *oldmode, UINT16 newmode, UINT16 flag )
1449 {
1450     FIXME("(%p,%p,%p,%d,%d), unimplemented.\n",
1451           newhandler,oldhandler,oldmode,newmode,flag );
1452
1453     if (flag != 1) return 0;
1454     if (!newmode) newhandler = NULL;  /* Default handler */
1455     if (newmode != 4)
1456     {
1457         TDB *pTask;
1458
1459         if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1460         if (oldmode) *oldmode = pTask->signal_flags;
1461         pTask->signal_flags = newmode;
1462         if (oldhandler) *oldhandler = pTask->sighandler;
1463         pTask->sighandler = newhandler;
1464     }
1465     return 0;
1466 }
1467
1468
1469 /***********************************************************************
1470  *           GlobalNotify   (KERNEL.154)
1471  *
1472  * Note that GlobalNotify does _not_ return the old NotifyProc
1473  * -- contrary to LocalNotify !!
1474  */
1475 VOID WINAPI GlobalNotify16( FARPROC16 proc )
1476 {
1477     TDB *pTask;
1478
1479     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
1480     pTask->discardhandler = proc;
1481 }
1482
1483
1484 /***********************************************************************
1485  *           GetExePtr   (KERNEL.133)
1486  */
1487 static inline HMODULE16 GetExePtrHelper( HANDLE16 handle, HTASK16 *hTask )
1488 {
1489     char *ptr;
1490     HANDLE16 owner;
1491
1492       /* Check for module handle */
1493
1494     if (!(ptr = GlobalLock16( handle ))) return 0;
1495     if (((NE_MODULE *)ptr)->magic == IMAGE_OS2_SIGNATURE) return handle;
1496
1497       /* Search for this handle inside all tasks */
1498
1499     *hTask = hFirstTask;
1500     while (*hTask)
1501     {
1502         TDB *pTask = (TDB *)GlobalLock16( *hTask );
1503         if ((*hTask == handle) ||
1504             (pTask->hInstance == handle) ||
1505             (pTask->hQueue == handle) ||
1506             (pTask->hPDB == handle)) return pTask->hModule;
1507         *hTask = pTask->hNext;
1508     }
1509
1510       /* Check the owner for module handle */
1511
1512     owner = FarGetOwner16( handle );
1513     if (!(ptr = GlobalLock16( owner ))) return 0;
1514     if (((NE_MODULE *)ptr)->magic == IMAGE_OS2_SIGNATURE) return owner;
1515
1516       /* Search for the owner inside all tasks */
1517
1518     *hTask = hFirstTask;
1519     while (*hTask)
1520     {
1521         TDB *pTask = (TDB *)GlobalLock16( *hTask );
1522         if ((*hTask == owner) ||
1523             (pTask->hInstance == owner) ||
1524             (pTask->hQueue == owner) ||
1525             (pTask->hPDB == owner)) return pTask->hModule;
1526         *hTask = pTask->hNext;
1527     }
1528
1529     return 0;
1530 }
1531
1532 HMODULE16 WINAPI WIN16_GetExePtr( HANDLE16 handle )
1533 {
1534     HTASK16 hTask = 0;
1535     HMODULE16 hModule = GetExePtrHelper( handle, &hTask );
1536     STACK16FRAME *frame = CURRENT_STACK16;
1537     frame->ecx = hModule;
1538     if (hTask) frame->es = hTask;
1539     return hModule;
1540 }
1541
1542 HMODULE16 WINAPI GetExePtr( HANDLE16 handle )
1543 {
1544     HTASK16 hTask = 0;
1545     return GetExePtrHelper( handle, &hTask );
1546 }
1547
1548
1549 /***********************************************************************
1550  *           TaskFirst   (TOOLHELP.63)
1551  */
1552 BOOL16 WINAPI TaskFirst16( TASKENTRY *lpte )
1553 {
1554     lpte->hNext = hFirstTask;
1555     return TaskNext16( lpte );
1556 }
1557
1558
1559 /***********************************************************************
1560  *           TaskNext   (TOOLHELP.64)
1561  */
1562 BOOL16 WINAPI TaskNext16( TASKENTRY *lpte )
1563 {
1564     TDB *pTask;
1565     INSTANCEDATA *pInstData;
1566
1567     TRACE_(toolhelp)("(%p): task=%04x\n", lpte, lpte->hNext );
1568     if (!lpte->hNext) return FALSE;
1569
1570     /* make sure that task and hInstance are valid (skip initial Wine task !) */
1571     while (1) {
1572         pTask = (TDB *)GlobalLock16( lpte->hNext );
1573         if (!pTask || pTask->magic != TDB_MAGIC) return FALSE;
1574         if (pTask->hInstance)
1575             break;
1576         lpte->hNext = pTask->hNext;
1577     }
1578     pInstData = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN( GlobalHandleToSel16(pTask->hInstance), 0 );
1579     lpte->hTask         = lpte->hNext;
1580     lpte->hTaskParent   = pTask->hParent;
1581     lpte->hInst         = pTask->hInstance;
1582     lpte->hModule       = pTask->hModule;
1583     lpte->wSS           = SELECTOROF( pTask->teb->cur_stack );
1584     lpte->wSP           = OFFSETOF( pTask->teb->cur_stack );
1585     lpte->wStackTop     = pInstData->stacktop;
1586     lpte->wStackMinimum = pInstData->stackmin;
1587     lpte->wStackBottom  = pInstData->stackbottom;
1588     lpte->wcEvents      = pTask->nEvents;
1589     lpte->hQueue        = pTask->hQueue;
1590     lstrcpynA( lpte->szModule, pTask->module_name, sizeof(lpte->szModule) );
1591     lpte->wPSPOffset    = 0x100;  /*??*/
1592     lpte->hNext         = pTask->hNext;
1593     return TRUE;
1594 }
1595
1596
1597 /***********************************************************************
1598  *           TaskFindHandle   (TOOLHELP.65)
1599  */
1600 BOOL16 WINAPI TaskFindHandle16( TASKENTRY *lpte, HTASK16 hTask )
1601 {
1602     lpte->hNext = hTask;
1603     return TaskNext16( lpte );
1604 }
1605
1606
1607 /***********************************************************************
1608  *           GetAppCompatFlags16   (KERNEL.354)
1609  */
1610 DWORD WINAPI GetAppCompatFlags16( HTASK16 hTask )
1611 {
1612     return GetAppCompatFlags( hTask );
1613 }
1614
1615
1616 /***********************************************************************
1617  *           GetAppCompatFlags   (USER32.206)
1618  */
1619 DWORD WINAPI GetAppCompatFlags( HTASK hTask )
1620 {
1621     TDB *pTask;
1622
1623     if (!hTask) hTask = GetCurrentTask();
1624     if (!(pTask=(TDB *)GlobalLock16( (HTASK16)hTask ))) return 0;
1625     if (GlobalSize16(hTask) < sizeof(TDB)) return 0;
1626     return pTask->compat_flags;
1627 }