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 "user.h"
  14 #include "callback.h"
  15 #include "drive.h"
  16 #include "file.h"
  17 #include "global.h"
  18 #include "instance.h"
  19 #include "message.h"
  20 #include "miscemu.h"
  21 #include "module.h"
  22 #include "neexe.h"
  23 #include "peexe.h"
  24 #include "pe_image.h"
  25 #include "process.h"
  26 #include "queue.h"
  27 #include "selectors.h"
  28 #include "stackframe.h"
  29 #include "task.h"
  30 #include "thread.h"
  31 #include "toolhelp.h"
  32 #include "winnt.h"
  33 #include "winsock.h"
  34 #include "thread.h"
  35 #include "syslevel.h"
  36 #include "debugtools.h"
  37 #include "dosexe.h"
  38 #include "services.h"
  39 #include "server.h"
  40
  41 DECLARE_DEBUG_CHANNEL(relay)
  42 DECLARE_DEBUG_CHANNEL(task)
  43 DECLARE_DEBUG_CHANNEL(toolhelp)
  44
  45   /* Min. number of thunks allocated when creating a new segment */
  46 #define MIN_THUNKS  32
  47
  48   /* Pointer to function to switch to a larger stack */
  49 int (*IF1632_CallLargeStack)( int (*func)(), void *arg ) = NULL;
  50
  51 static THHOOK DefaultThhook = { 0 };
  52 THHOOK *pThhook = &DefaultThhook;
  53
  54 #define hCurrentTask (pThhook->CurTDB)
  55 #define hFirstTask   (pThhook->HeadTDB)
  56 #define hLockedTask  (pThhook->LockTDB)
  57
  58 static UINT16 nTaskCount = 0;
  59
  60
  61 /***********************************************************************
  62  *           TASK_InstallTHHook
  63  */
  64 void TASK_InstallTHHook( THHOOK *pNewThhook )
  65 {
  66      THHOOK *pOldThhook = pThhook;
  67
  68      pThhook = pNewThhook? pNewThhook : &DefaultThhook;
  69
  70      *pThhook = *pOldThhook;
  71 }
  72
  73 /***********************************************************************
  74  *           TASK_GetNextTask
  75  */
  76 HTASK16 TASK_GetNextTask( HTASK16 hTask )
  77 {
  78     TDB* pTask = (TDB*)GlobalLock16(hTask);
  79
  80     if (pTask->hNext) return pTask->hNext;
  81     return (hFirstTask != hTask) ? hFirstTask : 0;
  82 }
  83
  84 /***********************************************************************
  85  *           TASK_LinkTask
  86  */
  87 static void TASK_LinkTask( HTASK16 hTask )
  88 {
  89     HTASK16 *prevTask;
  90     TDB *pTask;
  91
  92     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
  93     prevTask = &hFirstTask;
  94     while (*prevTask)
  95     {
  96         TDB *prevTaskPtr = (TDB *)GlobalLock16( *prevTask );
  97         if (prevTaskPtr->priority >= pTask->priority) break;
  98         prevTask = &prevTaskPtr->hNext;
  99     }
 100     pTask->hNext = *prevTask;
 101     *prevTask = hTask;
 102     nTaskCount++;
 103 }
 104
 105
 106 /***********************************************************************
 107  *           TASK_UnlinkTask
 108  */
 109 static void TASK_UnlinkTask( HTASK16 hTask )
 110 {
 111     HTASK16 *prevTask;
 112     TDB *pTask;
 113
 114     prevTask = &hFirstTask;
 115     while (*prevTask && (*prevTask != hTask))
 116     {
 117         pTask = (TDB *)GlobalLock16( *prevTask );
 118         prevTask = &pTask->hNext;
 119     }
 120     if (*prevTask)
 121     {
 122         pTask = (TDB *)GlobalLock16( *prevTask );
 123         *prevTask = pTask->hNext;
 124         pTask->hNext = 0;
 125         nTaskCount--;
 126     }
 127 }
 128
 129
 130 /***********************************************************************
 131  *           TASK_CreateThunks
 132  *
 133  * Create a thunk free-list in segment 'handle', starting from offset 'offset'
 134  * and containing 'count' entries.
 135  */
 136 static void TASK_CreateThunks( HGLOBAL16 handle, WORD offset, WORD count )
 137 {
 138     int i;
 139     WORD free;
 140     THUNKS *pThunk;
 141
 142     pThunk = (THUNKS *)((BYTE *)GlobalLock16( handle ) + offset);
 143     pThunk->next = 0;
 144     pThunk->magic = THUNK_MAGIC;
 145     pThunk->free = (int)&pThunk->thunks - (int)pThunk;
 146     free = pThunk->free;
 147     for (i = 0; i < count-1; i++)
 148     {
 149         free += 8;  /* Offset of next thunk */
 150         pThunk->thunks[4*i] = free;
 151     }
 152     pThunk->thunks[4*i] = 0;  /* Last thunk */
 153 }
 154
 155
 156 /***********************************************************************
 157  *           TASK_AllocThunk
 158  *
 159  * Allocate a thunk for MakeProcInstance().
 160  */
 161 static SEGPTR TASK_AllocThunk( HTASK16 hTask )
 162 {
 163     TDB *pTask;
 164     THUNKS *pThunk;
 165     WORD sel, base;
 166
 167     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
 168     sel = pTask->hCSAlias;
 169     pThunk = &pTask->thunks;
 170     base = (int)pThunk - (int)pTask;
 171     while (!pThunk->free)
 172     {
 173         sel = pThunk->next;
 174         if (!sel)  /* Allocate a new segment */
 175         {
 176             sel = GLOBAL_Alloc( GMEM_FIXED, sizeof(THUNKS) + (MIN_THUNKS-1)*8,
 177                                 pTask->hPDB, TRUE, FALSE, FALSE );
 178             if (!sel) return (SEGPTR)0;
 179             TASK_CreateThunks( sel, 0, MIN_THUNKS );
 180             pThunk->next = sel;
 181         }
 182         pThunk = (THUNKS *)GlobalLock16( sel );
 183         base = 0;
 184     }
 185     base += pThunk->free;
 186     pThunk->free = *(WORD *)((BYTE *)pThunk + pThunk->free);
 187     return PTR_SEG_OFF_TO_SEGPTR( sel, base );
 188 }
 189
 190
 191 /***********************************************************************
 192  *           TASK_FreeThunk
 193  *
 194  * Free a MakeProcInstance() thunk.
 195  */
 196 static BOOL TASK_FreeThunk( HTASK16 hTask, SEGPTR thunk )
 197 {
 198     TDB *pTask;
 199     THUNKS *pThunk;
 200     WORD sel, base;
 201
 202     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
 203     sel = pTask->hCSAlias;
 204     pThunk = &pTask->thunks;
 205     base = (int)pThunk - (int)pTask;
 206     while (sel && (sel != HIWORD(thunk)))
 207     {
 208         sel = pThunk->next;
 209         pThunk = (THUNKS *)GlobalLock16( sel );
 210         base = 0;
 211     }
 212     if (!sel) return FALSE;
 213     *(WORD *)((BYTE *)pThunk + LOWORD(thunk) - base) = pThunk->free;
 214     pThunk->free = LOWORD(thunk) - base;
 215     return TRUE;
 216 }
 217
 218
 219 /***********************************************************************
 220  *           TASK_CallToStart
 221  *
 222  * 32-bit entry point for a new task. This function is responsible for
 223  * setting up the registers and jumping to the 16-bit entry point.
 224  */
 225 void TASK_CallToStart(void)
 226 {
 227     TDB *pTask = (TDB *)GlobalLock16( GetCurrentTask() );
 228     NE_MODULE *pModule = NE_GetPtr( pTask->hModule );
 229     SEGTABLEENTRY *pSegTable = NE_SEG_TABLE( pModule );
 230     CONTEXT86 context;
 231
 232     /* Add task to 16-bit scheduler pool */
 233     TASK_Reschedule();
 234
 235     /* Registers at initialization must be:
 236      * ax   zero
 237      * bx   stack size in bytes
 238      * cx   heap size in bytes
 239      * si   previous app instance
 240      * di   current app instance
 241      * bp   zero
 242      * es   selector to the PSP
 243      * ds   dgroup of the application
 244      * ss   stack selector
 245      * sp   top of the stack
 246      */
 247
 248     memset( &context, 0, sizeof(context) );
 249     CS_reg(&context)  = GlobalHandleToSel16(pSegTable[pModule->cs - 1].hSeg);
 250     DS_reg(&context)  = GlobalHandleToSel16(pTask->hInstance);
 251     ES_reg(&context)  = pTask->hPDB;
 252     EIP_reg(&context) = pModule->ip;
 253     EBX_reg(&context) = pModule->stack_size;
 254     ECX_reg(&context) = pModule->heap_size;
 255     EDI_reg(&context) = pTask->hInstance;
 256     ESI_reg(&context) = pTask->hPrevInstance;
 257
 258     TRACE_(task)("Starting main program: cs:ip=%04lx:%04lx ds=%04lx ss:sp=%04x:%04x\n",
 259                   CS_reg(&context), EIP_reg(&context), DS_reg(&context),
 260                   SELECTOROF(pTask->teb->cur_stack),
 261                   OFFSETOF(pTask->teb->cur_stack) );
 262
 263     Callbacks->CallRegisterShortProc( &context, 0 );
 264 }
 265
 266
 267 /***********************************************************************
 268  *           TASK_Create
 269  *
 270  * NOTE: This routine might be called by a Win32 thread. Thus, we need
 271  *       to be careful to protect global data structures. We do this
 272  *       by entering the Win16Lock while linking the task into the
 273  *       global task list.
 274  */
 275 BOOL TASK_Create( NE_MODULE *pModule, UINT16 cmdShow)
 276 {
 277     HTASK16 hTask;
 278     TDB *pTask;
 279     LPSTR cmd_line;
 280     char name[10];
 281     PDB *pdb32 = PROCESS_Current();
 282
 283       /* Allocate the task structure */
 284
 285     hTask = GLOBAL_Alloc( GMEM_FIXED | GMEM_ZEROINIT, sizeof(TDB),
 286                           pModule->self, FALSE, FALSE, FALSE );
 287     if (!hTask) return FALSE;
 288     pTask = (TDB *)GlobalLock16( hTask );
 289
 290     /* Fill the task structure */
 291
 292     pTask->nEvents       = 0;
 293     pTask->hSelf         = hTask;
 294     pTask->flags         = 0;
 295
 296     if (pModule->flags & NE_FFLAGS_WIN32)
 297         pTask->flags    |= TDBF_WIN32;
 298     if (pModule->lpDosTask)
 299         pTask->flags    |= TDBF_WINOLDAP;
 300
 301     pTask->hInstance     = pModule->self;
 302     pTask->hPrevInstance = 0;
 303     /* NOTE: for 16-bit tasks, the instance handles are updated later on
 304              in NE_InitProcess */
 305
 306     pTask->version       = pModule->expected_version;
 307     pTask->hModule       = pModule->self;
 308     pTask->hParent       = GetCurrentTask();
 309     pTask->magic         = TDB_MAGIC;
 310     pTask->nCmdShow      = cmdShow;
 311     pTask->teb           = NtCurrentTeb();
 312     pTask->curdrive      = DRIVE_GetCurrentDrive() | 0x80;
 313     strcpy( pTask->curdir, "\\" );
 314     lstrcpynA( pTask->curdir + 1, DRIVE_GetDosCwd( DRIVE_GetCurrentDrive() ),
 315                  sizeof(pTask->curdir) - 1 );
 316
 317       /* Create the thunks block */
 318
 319     TASK_CreateThunks( hTask, (int)&pTask->thunks - (int)pTask, 7 );
 320
 321       /* Copy the module name */
 322
 323     GetModuleName16( pModule->self, name, sizeof(name) );
 324     strncpy( pTask->module_name, name, sizeof(pTask->module_name) );
 325
 326       /* Allocate a selector for the PDB */
 327
 328     pTask->hPDB = GLOBAL_CreateBlock( GMEM_FIXED, &pTask->pdb, sizeof(PDB16),
 329                                     pModule->self, FALSE, FALSE, FALSE, NULL );
 330
 331       /* Fill the PDB */
 332
 333     pTask->pdb.int20 = 0x20cd;
 334     pTask->pdb.dispatcher[0] = 0x9a;  /* ljmp */
 335     PUT_DWORD(&pTask->pdb.dispatcher[1], (DWORD)NE_GetEntryPoint(
 336            GetModuleHandle16("KERNEL"), 102 ));  /* KERNEL.102 is DOS3Call() */
 337     pTask->pdb.savedint22 = INT_GetPMHandler( 0x22 );
 338     pTask->pdb.savedint23 = INT_GetPMHandler( 0x23 );
 339     pTask->pdb.savedint24 = INT_GetPMHandler( 0x24 );
 340     pTask->pdb.fileHandlesPtr =
 341         PTR_SEG_OFF_TO_SEGPTR( GlobalHandleToSel16(pTask->hPDB),
 342                                (int)&((PDB16 *)0)->fileHandles );
 343     pTask->pdb.hFileHandles = 0;
 344     memset( pTask->pdb.fileHandles, 0xff, sizeof(pTask->pdb.fileHandles) );
 345     pTask->pdb.environment    = pdb32->env_db->env_sel;
 346     pTask->pdb.nbFiles        = 20;
 347
 348     /* Fill the command line */
 349
 350     cmd_line = pdb32->env_db->cmd_line;
 351     while (*cmd_line && (*cmd_line != ' ') && (*cmd_line != '\t')) cmd_line++;
 352     while ((*cmd_line == ' ') || (*cmd_line == '\t')) cmd_line++;
 353     lstrcpynA( pTask->pdb.cmdLine+1, cmd_line, sizeof(pTask->pdb.cmdLine)-1);
 354     pTask->pdb.cmdLine[0] = strlen( pTask->pdb.cmdLine + 1 );
 355
 356       /* Get the compatibility flags */
 357
 358     pTask->compat_flags = GetProfileIntA( "Compatibility", name, 0 );
 359
 360       /* Allocate a code segment alias for the TDB */
 361
 362     pTask->hCSAlias = GLOBAL_CreateBlock( GMEM_FIXED, (void *)pTask,
 363                                           sizeof(TDB), pTask->hPDB, TRUE,
 364                                           FALSE, FALSE, NULL );
 365
 366       /* Set the owner of the environment block */
 367
 368     FarSetOwner16( pTask->pdb.environment, pTask->hPDB );
 369
 370       /* Default DTA overwrites command-line */
 371
 372     pTask->dta = PTR_SEG_OFF_TO_SEGPTR( pTask->hPDB,
 373                                 (int)&pTask->pdb.cmdLine - (int)&pTask->pdb );
 374
 375     /* Create scheduler event for 16-bit tasks */
 376
 377     if ( !(pTask->flags & TDBF_WIN32) )
 378     {
 379         pTask->hEvent = CreateEventA( NULL, TRUE, FALSE, NULL );
 380         pTask->hEvent = ConvertToGlobalHandle( pTask->hEvent );
 381     }
 382
 383     /* Enter task handle into thread and process */
 384
 385     pTask->teb->htask16 = pTask->teb->process->task = hTask;
 386     TRACE_(task)("module='%s' cmdline='%s' task=%04x\n", name, cmd_line, hTask );
 387
 388     /* Add the task to the linked list */
 389
 390     SYSLEVEL_EnterWin16Lock();
 391     TASK_LinkTask( hTask );
 392     SYSLEVEL_LeaveWin16Lock();
 393
 394     return TRUE;
 395 }
 396
 397 /***********************************************************************
 398  *           TASK_DeleteTask
 399  */
 400 static void TASK_DeleteTask( HTASK16 hTask )
 401 {
 402     TDB *pTask;
 403     HGLOBAL16 hPDB;
 404
 405     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 406     hPDB = pTask->hPDB;
 407
 408     pTask->magic = 0xdead; /* invalidate signature */
 409
 410     /* Delete the Win32 part of the task */
 411
 412 /*    PROCESS_FreePDB( pTask->teb->process ); FIXME */
 413 /*    K32OBJ_DecCount( &pTask->teb->header ); FIXME */
 414
 415     /* Free the selector aliases */
 416
 417     GLOBAL_FreeBlock( pTask->hCSAlias );
 418     GLOBAL_FreeBlock( pTask->hPDB );
 419
 420     /* Free the task module */
 421
 422     FreeModule16( pTask->hModule );
 423
 424     /* Free the task structure itself */
 425
 426     GlobalFree16( hTask );
 427
 428     /* Free all memory used by this task (including the 32-bit stack, */
 429     /* the environment block and the thunk segments). */
 430
 431     GlobalFreeAll16( hPDB );
 432 }
 433
 434 /***********************************************************************
 435  *           TASK_KillTask
 436  */
 437 void TASK_KillTask( HTASK16 hTask )
 438 {
 439     TDB *pTask;
 440
 441     /* Enter the Win16Lock to protect global data structures */
 442     SYSLEVEL_EnterWin16Lock();
 443
 444     if ( !hTask ) hTask = GetCurrentTask();
 445     pTask = (TDB *)GlobalLock16( hTask );
 446     if ( !pTask )
 447     {
 448         SYSLEVEL_LeaveWin16Lock();
 449         return;
 450     }
 451
 452     TRACE_(task)("Killing task %04x\n", hTask );
 453
 454 #ifdef MZ_SUPPORTED
 455 {
 456     /* Kill DOS VM task */
 457     NE_MODULE *pModule = NE_GetPtr( pTask->hModule );
 458     if ( pModule->lpDosTask )
 459         MZ_KillModule( pModule->lpDosTask );
 460 }
 461 #endif
 462
 463     /* Perform USER cleanup */
 464
 465     TASK_CallTaskSignalProc( USIG16_TERMINATION, hTask );
 466     PROCESS_CallUserSignalProc( USIG_PROCESS_EXIT, 0 );
 467     PROCESS_CallUserSignalProc( USIG_THREAD_EXIT, 0 );     /* FIXME */
 468     PROCESS_CallUserSignalProc( USIG_PROCESS_DESTROY, 0 );
 469
 470     if (nTaskCount <= 1)
 471     {
 472         TRACE_(task)("this is the last task, exiting\n" );
 473         ExitKernel16();
 474     }
 475
 476     /* FIXME: Hack! Send a message to the initial task so that
 477      * the GetMessage wakes up and the initial task can check whether
 478      * it is the only remaining one and terminate itself ...
 479      * The initial task should probably install hooks or something
 480      * to get informed about task termination :-/
 481      */
 482     Callout.PostAppMessage16( PROCESS_Initial()->task, WM_NULL, 0, 0 );
 483
 484     /* Remove the task from the list to be sure we never switch back to it */
 485     TASK_UnlinkTask( hTask );
 486     if( nTaskCount )
 487     {
 488         TDB* p = (TDB *)GlobalLock16( hFirstTask );
 489         while( p )
 490         {
 491             if( p->hYieldTo == hTask ) p->hYieldTo = 0;
 492             p = (TDB *)GlobalLock16( p->hNext );
 493         }
 494     }
 495
 496     pTask->nEvents = 0;
 497
 498     if ( hLockedTask == hTask )
 499         hLockedTask = 0;
 500
 501     TASK_DeleteTask( hTask );
 502
 503     /* When deleting the current task ... */
 504     if ( hTask == hCurrentTask )
 505     {
 506         DWORD lockCount;
 507
 508         /* ... schedule another one ... */
 509         TASK_Reschedule();
 510
 511         /* ... and completely release the Win16Lock, just in case. */
 512         ReleaseThunkLock( &lockCount );
 513
 514         return;
 515     }
 516
 517     SYSLEVEL_LeaveWin16Lock();
 518 }
 519
 520 /***********************************************************************
 521  *           TASK_Reschedule
 522  *
 523  * This is where all the magic of task-switching happens!
 524  *
 525  * 16-bit Windows performs non-preemptive (cooperative) multitasking.
 526  * This means that each 16-bit task runs until it voluntarily yields
 527  * control, at which point the scheduler gets active and selects the
 528  * next task to run.
 529  *
 530  * In Wine, all processes, even 16-bit ones, are scheduled preemptively
 531  * by the standard scheduler of the underlying OS.  As many 16-bit apps
 532  * *rely* on the behaviour of the Windows scheduler, however, we have
 533  * to simulate that behaviour.
 534  *
 535  * This is achieved as follows: every 16-bit task is at time (except
 536  * during task creation and deletion) in one of two states: either it
 537  * is the one currently running, then the global variable hCurrentTask
 538  * contains its task handle, or it is not currently running, then it
 539  * is blocked on a special scheduler event, a global handle to which
 540  * is stored in the task struct.
 541  *
 542  * When the current task yields control, this routine gets called. Its
 543  * purpose is to determine the next task to be active, signal the
 544  * scheduler event of that task, and then put the current task to sleep
 545  * waiting for *its* scheduler event to get signalled again.
 546  *
 547  * This routine can get called in a few other special situations as well:
 548  *
 549  * - On creation of a 16-bit task, the Unix process executing the task
 550  *   calls TASK_Reschedule once it has completed its initialization.
 551  *   At this point, the task needs to be blocked until its scheduler
 552  *   event is signalled the first time (this will be done by the parent
 553  *   process to get the task up and running).
 554  *
 555  * - When the task currently running terminates itself, this routine gets
 556  *   called and has to schedule another task, *without* blocking the
 557  *   terminating task.
 558  *
 559  * - When a 32-bit thread posts an event for a 16-bit task, it might be
 560  *   the case that *no* 16-bit task is currently running.  In this case
 561  *   the task that has now an event pending is to be scheduled.
 562  *
 563  */
 564 void TASK_Reschedule(void)
 565 {
 566     TDB *pOldTask = NULL, *pNewTask = NULL;
 567     HTASK16 hOldTask = 0, hNewTask = 0;
 568     enum { MODE_YIELD, MODE_SLEEP, MODE_WAKEUP } mode;
 569     DWORD lockCount;
 570
 571     SYSLEVEL_EnterWin16Lock();
 572
 573     /* Check what we need to do */
 574     hOldTask = GetCurrentTask();
 575     pOldTask = (TDB *)GlobalLock16( hOldTask );
 576     TRACE_(task)( "entered with hCurrentTask %04x by hTask %04x (pid %ld)\n",
 577                   hCurrentTask, hOldTask, (long) getpid() );
 578
 579     if ( pOldTask && THREAD_IsWin16( NtCurrentTeb() ) )
 580     {
 581         /* We are called by an active (non-deleted) 16-bit task */
 582
 583         /* If we don't even have a current task, or else the current
 584            task has yielded, we'll need to schedule a new task and
 585            (possibly) put the calling task to sleep.  Otherwise, we
 586            only block the caller. */
 587
 588         if ( !hCurrentTask || hCurrentTask == hOldTask )
 589             mode = MODE_YIELD;
 590         else
 591             mode = MODE_SLEEP;
 592     }
 593     else
 594     {
 595         /* We are called by a deleted 16-bit task or a 32-bit thread */
 596
 597         /* The only situation where we need to do something is if we
 598            now do not have a current task.  Then, we'll need to wake up
 599            some task that has events pending. */
 600
 601         if ( !hCurrentTask || hCurrentTask == hOldTask )
 602             mode = MODE_WAKEUP;
 603         else
 604         {
 605             /* nothing to do */
 606             SYSLEVEL_LeaveWin16Lock();
 607             return;
 608         }
 609     }
 610
 611     /* Find a task to yield to: check for DirectedYield() */
 612     if ( mode == MODE_YIELD && pOldTask && pOldTask->hYieldTo )
 613     {
 614         hNewTask = pOldTask->hYieldTo;
 615         pNewTask = (TDB *)GlobalLock16( hNewTask );
 616         if( !pNewTask || !pNewTask->nEvents) hNewTask = 0;
 617         pOldTask->hYieldTo = 0;
 618     }
 619
 620     /* Find a task to yield to: check for pending events */
 621     if ( (mode == MODE_YIELD || mode == MODE_WAKEUP) && !hNewTask )
 622     {
 623         hNewTask = hFirstTask;
 624         while (hNewTask)
 625         {
 626             pNewTask = (TDB *)GlobalLock16( hNewTask );
 627
 628             TRACE_(task)( "\ttask = %04x, events = %i\n",
 629                           hNewTask, pNewTask->nEvents );
 630
 631             if (pNewTask->nEvents) break;
 632             hNewTask = pNewTask->hNext;
 633         }
 634         if (hLockedTask && (hNewTask != hLockedTask)) hNewTask = 0;
 635     }
 636
 637     /* If we are still the task with highest priority, just return ... */
 638     if ( mode == MODE_YIELD && hNewTask == hCurrentTask )
 639     {
 640         TRACE_(task)("returning to the current task (%04x)\n", hCurrentTask );
 641         SYSLEVEL_LeaveWin16Lock();
 642
 643         /* Allow Win32 threads to thunk down even while a Win16 task is
 644            in a tight PeekMessage() or Yield() loop ... */
 645         ReleaseThunkLock( &lockCount );
 646         RestoreThunkLock( lockCount );
 647         return;
 648     }
 649
 650     /* If no task to yield to found, suspend 16-bit scheduler ... */
 651     if ( mode == MODE_YIELD && !hNewTask )
 652     {
 653         TRACE_(task)("No currently active task\n");
 654         hCurrentTask = 0;
 655     }
 656
 657     /* If we found a task to wake up, do it ... */
 658     if ( (mode == MODE_YIELD || mode == MODE_WAKEUP) && hNewTask )
 659     {
 660         TRACE_(task)("Switching to task %04x (%.8s)\n",
 661                       hNewTask, pNewTask->module_name );
 662
 663         pNewTask->priority++;
 664         TASK_UnlinkTask( hNewTask );
 665         TASK_LinkTask( hNewTask );
 666         pNewTask->priority--;
 667
 668         hCurrentTask = hNewTask;
 669         SetEvent( pNewTask->hEvent );
 670
 671         /* This is set just in case some app reads it ... */
 672         pNewTask->ss_sp = pNewTask->teb->cur_stack;
 673     }
 674
 675     /* If we need to put the current task to sleep, do it ... */
 676     if ( (mode == MODE_YIELD || mode == MODE_SLEEP) && hOldTask != hCurrentTask )
 677     {
 678         ResetEvent( pOldTask->hEvent );
 679
 680         ReleaseThunkLock( &lockCount );
 681         SYSLEVEL_CheckNotLevel( 1 );
 682         WaitForSingleObject( pOldTask->hEvent, INFINITE );
 683         RestoreThunkLock( lockCount );
 684     }
 685
 686     SYSLEVEL_LeaveWin16Lock();
 687 }
 688
 689 /***********************************************************************
 690  *           InitTask  (KERNEL.91)
 691  *
 692  * Called by the application startup code.
 693  */
 694 void WINAPI InitTask16( CONTEXT86 *context )
 695 {
 696     TDB *pTask;
 697     INSTANCEDATA *pinstance;
 698     SEGPTR ptr;
 699
 700     EAX_reg(context) = 0;
 701     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
 702
 703     /* Note: we need to trust that BX/CX contain the stack/heap sizes,
 704        as some apps, notably Visual Basic apps, *modify* the heap/stack
 705        size of the instance data segment before calling InitTask() */
 706
 707     /* Initialize the INSTANCEDATA structure */
 708     pinstance = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN(CURRENT_DS, 0);
 709     pinstance->stackmin    = OFFSETOF( pTask->teb->cur_stack );
 710     pinstance->stackbottom = pinstance->stackmin; /* yup, that's right. Confused me too. */
 711     pinstance->stacktop    = ( pinstance->stackmin > BX_reg(context)?
 712                                pinstance->stackmin - BX_reg(context) : 0 ) + 150;
 713
 714     /* Initialize the local heap */
 715     if ( CX_reg(context) )
 716         LocalInit16( pTask->hInstance, 0, CX_reg(context) );
 717
 718     /* Initialize implicitly loaded DLLs */
 719     NE_InitializeDLLs( pTask->hModule );
 720
 721     /* Registers on return are:
 722      * ax     1 if OK, 0 on error
 723      * cx     stack limit in bytes
 724      * dx     cmdShow parameter
 725      * si     instance handle of the previous instance
 726      * di     instance handle of the new task
 727      * es:bx  pointer to command-line inside PSP
 728      *
 729      * 0 (=%bp) is pushed on the stack
 730      */
 731     ptr = stack16_push( sizeof(WORD) );
 732     *(WORD *)PTR_SEG_TO_LIN(ptr) = 0;
 733     ESP_reg(context) -= 2;
 734
 735     EAX_reg(context) = 1;
 736
 737     if (!pTask->pdb.cmdLine[0]) EBX_reg(context) = 0x80;
 738     else
 739     {
 740         LPBYTE p = &pTask->pdb.cmdLine[1];
 741         while ((*p == ' ') || (*p == '\t')) p++;
 742         EBX_reg(context) = 0x80 + (p - pTask->pdb.cmdLine);
 743     }
 744     ECX_reg(context) = pinstance->stacktop;
 745     EDX_reg(context) = pTask->nCmdShow;
 746     ESI_reg(context) = (DWORD)pTask->hPrevInstance;
 747     EDI_reg(context) = (DWORD)pTask->hInstance;
 748     ES_reg (context) = (WORD)pTask->hPDB;
 749 }
 750
 751
 752 /***********************************************************************
 753  *           WaitEvent  (KERNEL.30)
 754  */
 755 BOOL16 WINAPI WaitEvent16( HTASK16 hTask )
 756 {
 757     TDB *pTask;
 758
 759     if (!hTask) hTask = GetCurrentTask();
 760     pTask = (TDB *)GlobalLock16( hTask );
 761
 762     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 763     {
 764         FIXME_(task)("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 765         return TRUE;
 766     }
 767
 768     if (pTask->nEvents > 0)
 769     {
 770         pTask->nEvents--;
 771         return FALSE;
 772     }
 773     TASK_Reschedule();
 774
 775     /* When we get back here, we have an event */
 776
 777     if (pTask->nEvents > 0) pTask->nEvents--;
 778     return TRUE;
 779 }
 780
 781
 782 /***********************************************************************
 783  *           PostEvent  (KERNEL.31)
 784  */
 785 void WINAPI PostEvent16( HTASK16 hTask )
 786 {
 787     TDB *pTask;
 788
 789     if (!hTask) hTask = GetCurrentTask();
 790     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 791
 792     if ( !THREAD_IsWin16( pTask->teb ) )
 793     {
 794         FIXME_(task)("called for Win32 thread (%04x)!\n", pTask->teb->teb_sel );
 795         return;
 796     }
 797
 798     pTask->nEvents++;
 799
 800     /* If we are a 32-bit task, we might need to wake up the 16-bit scheduler */
 801     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 802         TASK_Reschedule();
 803 }
 804
 805
 806 /***********************************************************************
 807  *           SetPriority  (KERNEL.32)
 808  */
 809 void WINAPI SetPriority16( HTASK16 hTask, INT16 delta )
 810 {
 811     TDB *pTask;
 812     INT16 newpriority;
 813
 814     if (!hTask) hTask = GetCurrentTask();
 815     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 816     newpriority = pTask->priority + delta;
 817     if (newpriority < -32) newpriority = -32;
 818     else if (newpriority > 15) newpriority = 15;
 819
 820     pTask->priority = newpriority + 1;
 821     TASK_UnlinkTask( hTask );
 822     TASK_LinkTask( hTask );
 823     pTask->priority--;
 824 }
 825
 826
 827 /***********************************************************************
 828  *           LockCurrentTask  (KERNEL.33)
 829  */
 830 HTASK16 WINAPI LockCurrentTask16( BOOL16 bLock )
 831 {
 832     if (bLock) hLockedTask = GetCurrentTask();
 833     else hLockedTask = 0;
 834     return hLockedTask;
 835 }
 836
 837
 838 /***********************************************************************
 839  *           IsTaskLocked  (KERNEL.122)
 840  */
 841 HTASK16 WINAPI IsTaskLocked16(void)
 842 {
 843     return hLockedTask;
 844 }
 845
 846
 847 /***********************************************************************
 848  *           OldYield  (KERNEL.117)
 849  */
 850 void WINAPI OldYield16(void)
 851 {
 852     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 853
 854     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 855     {
 856         FIXME_(task)("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 857         return;
 858     }
 859
 860     if (pCurTask) pCurTask->nEvents++;  /* Make sure we get back here */
 861     TASK_Reschedule();
 862     if (pCurTask) pCurTask->nEvents--;
 863 }
 864
 865 /***********************************************************************
 866  *           WIN32_OldYield16  (KERNEL.447)
 867  */
 868 void WINAPI WIN32_OldYield16(void)
 869 {
 870    DWORD count;
 871
 872    ReleaseThunkLock(&count);
 873    RestoreThunkLock(count);
 874 }
 875
 876 /***********************************************************************
 877  *           DirectedYield  (KERNEL.150)
 878  */
 879 void WINAPI DirectedYield16( HTASK16 hTask )
 880 {
 881     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 882
 883     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 884     {
 885         FIXME_(task)("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 886         return;
 887     }
 888
 889     TRACE_(task)("%04x: DirectedYield(%04x)\n", pCurTask->hSelf, hTask );
 890
 891     pCurTask->hYieldTo = hTask;
 892     OldYield16();
 893
 894     TRACE_(task)("%04x: back from DirectedYield(%04x)\n", pCurTask->hSelf, hTask );
 895 }
 896
 897 /***********************************************************************
 898  *           Yield16  (KERNEL.29)
 899  */
 900 void WINAPI Yield16(void)
 901 {
 902     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 903
 904     if (pCurTask) pCurTask->hYieldTo = 0;
 905     if (pCurTask && pCurTask->hQueue) Callout.UserYield16();
 906     else OldYield16();
 907 }
 908
 909 /***********************************************************************
 910  *           KERNEL_490  (KERNEL.490)
 911  */
 912 HTASK16 WINAPI KERNEL_490( HTASK16 someTask )
 913 {
 914     if ( !someTask ) return 0;
 915
 916     FIXME_(task)("(%04x): stub\n", someTask );
 917     return 0;
 918 }
 919
 920 /***********************************************************************
 921  *           MakeProcInstance16  (KERNEL.51)
 922  */
 923 FARPROC16 WINAPI MakeProcInstance16( FARPROC16 func, HANDLE16 hInstance )
 924 {
 925     BYTE *thunk,*lfunc;
 926     SEGPTR thunkaddr;
 927
 928     if (!func) {
 929       ERR_(task)("Ouch ! MakeProcInstance called with func == NULL !\n");
 930       return (FARPROC16)0; /* Windows seems to do the same */
 931     }
 932     if ( GetTaskDS16() !=hInstance )
 933     {
 934         ERR_(task)("Problem with hInstance? Got %04x, using %04x instead\n",
 935                    hInstance,GetTaskDS16());
 936         hInstance = GetTaskDS16();
 937     }
 938     if (!hInstance) hInstance = CURRENT_DS;
 939     thunkaddr = TASK_AllocThunk( GetCurrentTask() );
 940     if (!thunkaddr) return (FARPROC16)0;
 941     thunk = PTR_SEG_TO_LIN( thunkaddr );
 942     lfunc = PTR_SEG_TO_LIN( func );
 943
 944     TRACE_(task)("(%08lx,%04x): got thunk %08lx\n",
 945                   (DWORD)func, hInstance, (DWORD)thunkaddr );
 946     if (((lfunc[0]==0x8c) && (lfunc[1]==0xd8)) ||
 947         ((lfunc[0]==0x1e) && (lfunc[1]==0x58))
 948     ) {
 949         FIXME_(task)("thunk would be useless for %p, overwriting with nop;nop;\n", func );
 950         lfunc[0]=0x90; /* nop */
 951         lfunc[1]=0x90; /* nop */
 952     }
 953
 954     *thunk++ = 0xb8;    /* movw instance, %ax */
 955     *thunk++ = (BYTE)(hInstance & 0xff);
 956     *thunk++ = (BYTE)(hInstance >> 8);
 957     *thunk++ = 0xea;    /* ljmp func */
 958     *(DWORD *)thunk = (DWORD)func;
 959     return (FARPROC16)thunkaddr;
 960 }
 961
 962
 963 /***********************************************************************
 964  *           FreeProcInstance16  (KERNEL.52)
 965  */
 966 void WINAPI FreeProcInstance16( FARPROC16 func )
 967 {
 968     TRACE_(task)("(%08lx)\n", (DWORD)func );
 969     TASK_FreeThunk( GetCurrentTask(), (SEGPTR)func );
 970 }
 971
 972 /**********************************************************************
 973  *          TASK_GetCodeSegment
 974  *
 975  * Helper function for GetCodeHandle/GetCodeInfo: Retrieve the module
 976  * and logical segment number of a given code segment.
 977  *
 978  * 'proc' either *is* already a pair of module handle and segment number,
 979  * in which case there's nothing to do.  Otherwise, it is a pointer to
 980  * a function, and we need to retrieve the code segment.  If the pointer
 981  * happens to point to a thunk, we'll retrieve info about the code segment
 982  * where the function pointed to by the thunk resides, not the thunk itself.
 983  *
 984  * FIXME: if 'proc' is a SNOOP16 return stub, we should retrieve info about
 985  *        the function the snoop code will return to ...
 986  *
 987  */
 988 static BOOL TASK_GetCodeSegment( FARPROC16 proc, NE_MODULE **ppModule,
 989                                  SEGTABLEENTRY **ppSeg, int *pSegNr )
 990 {
 991     NE_MODULE *pModule = NULL;
 992     SEGTABLEENTRY *pSeg = NULL;
 993     int segNr;
 994
 995     /* Try pair of module handle / segment number */
 996     pModule = (NE_MODULE *) GlobalLock16( HIWORD( proc ) );
 997     if ( pModule && pModule->magic == IMAGE_OS2_SIGNATURE )
 998     {
 999         segNr = LOWORD( proc );
1000         if ( segNr && segNr <= pModule->seg_count )
1001             pSeg = NE_SEG_TABLE( pModule ) + segNr-1;
1002     }
1003
1004     /* Try thunk or function */
1005     else
1006     {
1007         BYTE *thunk = (BYTE *)PTR_SEG_TO_LIN( proc );
1008         WORD selector;
1009
1010         if ((thunk[0] == 0xb8) && (thunk[3] == 0xea))
1011             selector = thunk[6] + (thunk[7] << 8);
1012         else
1013             selector = HIWORD( proc );
1014
1015         pModule = NE_GetPtr( GlobalHandle16( selector ) );
1016         pSeg = pModule? NE_SEG_TABLE( pModule ) : NULL;
1017
1018         if ( pModule )
1019             for ( segNr = 1; segNr <= pModule->seg_count; segNr++, pSeg++ )
1020                 if ( GlobalHandleToSel16(pSeg->hSeg) == selector )
1021                     break;
1022
1023         if ( pModule && segNr > pModule->seg_count )
1024             pSeg = NULL;
1025     }
1026
1027     /* Abort if segment not found */
1028
1029     if ( !pModule || !pSeg )
1030         return FALSE;
1031
1032     /* Return segment data */
1033
1034     if ( ppModule ) *ppModule = pModule;
1035     if ( ppSeg    ) *ppSeg    = pSeg;
1036     if ( pSegNr   ) *pSegNr   = segNr;
1037
1038     return TRUE;
1039 }
1040
1041 /**********************************************************************
1042  *          GetCodeHandle    (KERNEL.93)
1043  */
1044 HANDLE16 WINAPI GetCodeHandle16( FARPROC16 proc )
1045 {
1046     SEGTABLEENTRY *pSeg;
1047
1048     if ( !TASK_GetCodeSegment( proc, NULL, &pSeg, NULL ) )
1049         return (HANDLE16)0;
1050
1051     return pSeg->hSeg;
1052 }
1053
1054 /**********************************************************************
1055  *          GetCodeInfo    (KERNEL.104)
1056  */
1057 BOOL16 WINAPI GetCodeInfo16( FARPROC16 proc, SEGINFO *segInfo )
1058 {
1059     NE_MODULE *pModule;
1060     SEGTABLEENTRY *pSeg;
1061     int segNr;
1062
1063     if ( !TASK_GetCodeSegment( proc, &pModule, &pSeg, &segNr ) )
1064         return FALSE;
1065
1066     /* Fill in segment information */
1067
1068     segInfo->offSegment = pSeg->filepos;
1069     segInfo->cbSegment  = pSeg->size;
1070     segInfo->flags      = pSeg->flags;
1071     segInfo->cbAlloc    = pSeg->minsize;
1072     segInfo->h          = pSeg->hSeg;
1073     segInfo->alignShift = pModule->alignment;
1074
1075     if ( segNr == pModule->dgroup )
1076         segInfo->cbAlloc += pModule->heap_size + pModule->stack_size;
1077
1078     /* Return module handle in %es */
1079
1080     CURRENT_STACK16->es = GlobalHandleToSel16( pModule->self );
1081
1082     return TRUE;
1083 }
1084
1085
1086 /**********************************************************************
1087  *          DefineHandleTable16    (KERNEL.94)
1088  */
1089 BOOL16 WINAPI DefineHandleTable16( WORD wOffset )
1090 {
1091     return TRUE;  /* FIXME */
1092 }
1093
1094
1095 /***********************************************************************
1096  *           SetTaskQueue  (KERNEL.34)
1097  */
1098 HQUEUE16 WINAPI SetTaskQueue16( HTASK16 hTask, HQUEUE16 hQueue )
1099 {
1100     HQUEUE16 hPrev;
1101     TDB *pTask;
1102
1103     if (!hTask) hTask = GetCurrentTask();
1104     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
1105
1106     hPrev = pTask->hQueue;
1107     pTask->hQueue = hQueue;
1108
1109     return hPrev;
1110 }
1111
1112
1113 /***********************************************************************
1114  *           GetTaskQueue  (KERNEL.35)
1115  */
1116 HQUEUE16 WINAPI GetTaskQueue16( HTASK16 hTask )
1117 {
1118     TDB *pTask;
1119
1120     if (!hTask) hTask = GetCurrentTask();
1121     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
1122     return pTask->hQueue;
1123 }
1124
1125 /***********************************************************************
1126  *           SetThreadQueue  (KERNEL.463)
1127  */
1128 HQUEUE16 WINAPI SetThreadQueue16( DWORD thread, HQUEUE16 hQueue )
1129 {
1130     TEB *teb = thread? THREAD_IdToTEB( thread ) : NtCurrentTeb();
1131     HQUEUE16 oldQueue = teb? teb->queue : 0;
1132
1133     if ( teb )
1134     {
1135         teb->queue = hQueue;
1136
1137         if ( GetTaskQueue16( teb->process->task ) == oldQueue )
1138             SetTaskQueue16( teb->process->task, hQueue );
1139     }
1140
1141     return oldQueue;
1142 }
1143
1144 /***********************************************************************
1145  *           GetThreadQueue  (KERNEL.464)
1146  */
1147 HQUEUE16 WINAPI GetThreadQueue16( DWORD thread )
1148 {
1149     TEB *teb = NULL;
1150     if ( !thread )
1151         teb = NtCurrentTeb();
1152     else if ( HIWORD(thread) )
1153         teb = THREAD_IdToTEB( thread );
1154     else if ( IsTask16( (HTASK16)thread ) )
1155         teb = ((TDB *)GlobalLock16( (HANDLE16)thread ))->teb;
1156
1157     return (HQUEUE16)(teb? teb->queue : 0);
1158 }
1159
1160 /***********************************************************************
1161  *           SetFastQueue  (KERNEL.624)
1162  */
1163 VOID WINAPI SetFastQueue16( DWORD thread, HANDLE hQueue )
1164 {
1165     TEB *teb = NULL;
1166     if ( !thread )
1167         teb = NtCurrentTeb();
1168     else if ( HIWORD(thread) )
1169         teb = THREAD_IdToTEB( thread );
1170     else if ( IsTask16( (HTASK16)thread ) )
1171         teb = ((TDB *)GlobalLock16( (HANDLE16)thread ))->teb;
1172
1173     if ( teb ) teb->queue = (HQUEUE16) hQueue;
1174 }
1175
1176 /***********************************************************************
1177  *           GetFastQueue  (KERNEL.625)
1178  */
1179 HANDLE WINAPI GetFastQueue16( void )
1180 {
1181     TEB *teb = NtCurrentTeb();
1182     if (!teb) return 0;
1183
1184     if (!teb->queue)
1185         Callout.InitThreadInput16( 0, THREAD_IsWin16(teb)? 4 : 5 );
1186
1187     if (!teb->queue)
1188         FIXME_(task)("(): should initialize thread-local queue, expect failure!\n" );
1189
1190     return (HANDLE)teb->queue;
1191 }
1192
1193 /***********************************************************************
1194  *           SwitchStackTo   (KERNEL.108)
1195  */
1196 void WINAPI SwitchStackTo16( WORD seg, WORD ptr, WORD top )
1197 {
1198     TDB *pTask;
1199     STACK16FRAME *oldFrame, *newFrame;
1200     INSTANCEDATA *pData;
1201     UINT16 copySize;
1202
1203     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
1204     if (!(pData = (INSTANCEDATA *)GlobalLock16( seg ))) return;
1205     TRACE_(task)("old=%04x:%04x new=%04x:%04x\n",
1206                   SELECTOROF( pTask->teb->cur_stack ),
1207                   OFFSETOF( pTask->teb->cur_stack ), seg, ptr );
1208
1209     /* Save the old stack */
1210
1211     oldFrame = THREAD_STACK16( pTask->teb );
1212     /* pop frame + args and push bp */
1213     pData->old_ss_sp   = pTask->teb->cur_stack + sizeof(STACK16FRAME)
1214                            + 2 * sizeof(WORD);
1215     *(WORD *)PTR_SEG_TO_LIN(pData->old_ss_sp) = oldFrame->bp;
1216     pData->stacktop    = top;
1217     pData->stackmin    = ptr;
1218     pData->stackbottom = ptr;
1219
1220     /* Switch to the new stack */
1221
1222     /* Note: we need to take the 3 arguments into account; otherwise,
1223      * the stack will underflow upon return from this function.
1224      */
1225     copySize = oldFrame->bp - OFFSETOF(pData->old_ss_sp);
1226     copySize += 3 * sizeof(WORD) + sizeof(STACK16FRAME);
1227     pTask->teb->cur_stack = PTR_SEG_OFF_TO_SEGPTR( seg, ptr - copySize );
1228     newFrame = THREAD_STACK16( pTask->teb );
1229
1230     /* Copy the stack frame and the local variables to the new stack */
1231
1232     memmove( newFrame, oldFrame, copySize );
1233     newFrame->bp = ptr;
1234     *(WORD *)PTR_SEG_OFF_TO_LIN( seg, ptr ) = 0;  /* clear previous bp */
1235 }
1236
1237
1238 /***********************************************************************
1239  *           SwitchStackBack   (KERNEL.109)
1240  */
1241 void WINAPI SwitchStackBack16( CONTEXT86 *context )
1242 {
1243     STACK16FRAME *oldFrame, *newFrame;
1244     INSTANCEDATA *pData;
1245
1246     if (!(pData = (INSTANCEDATA *)GlobalLock16(SELECTOROF(NtCurrentTeb()->cur_stack))))
1247         return;
1248     if (!pData->old_ss_sp)
1249     {
1250         WARN_(task)("No previous SwitchStackTo\n" );
1251         return;
1252     }
1253     TRACE_(task)("restoring stack %04x:%04x\n",
1254                  SELECTOROF(pData->old_ss_sp), OFFSETOF(pData->old_ss_sp) );
1255
1256     oldFrame = CURRENT_STACK16;
1257
1258     /* Pop bp from the previous stack */
1259
1260     BP_reg(context) = *(WORD *)PTR_SEG_TO_LIN(pData->old_ss_sp);
1261     pData->old_ss_sp += sizeof(WORD);
1262
1263     /* Switch back to the old stack */
1264
1265     NtCurrentTeb()->cur_stack = pData->old_ss_sp - sizeof(STACK16FRAME);
1266     SS_reg(context)  = SELECTOROF(pData->old_ss_sp);
1267     ESP_reg(context) = OFFSETOF(pData->old_ss_sp) - sizeof(DWORD); /*ret addr*/
1268     pData->old_ss_sp = 0;
1269
1270     /* Build a stack frame for the return */
1271
1272     newFrame = CURRENT_STACK16;
1273     newFrame->frame32     = oldFrame->frame32;
1274     newFrame->module_cs   = oldFrame->module_cs;
1275     newFrame->callfrom_ip = oldFrame->callfrom_ip;
1276     newFrame->entry_ip    = oldFrame->entry_ip;
1277 }
1278
1279
1280 /***********************************************************************
1281  *           GetTaskQueueDS16  (KERNEL.118)
1282  */
1283 void WINAPI GetTaskQueueDS16(void)
1284 {
1285     CURRENT_STACK16->ds = GlobalHandleToSel16( GetTaskQueue16(0) );
1286 }
1287
1288
1289 /***********************************************************************
1290  *           GetTaskQueueES16  (KERNEL.119)
1291  */
1292 void WINAPI GetTaskQueueES16(void)
1293 {
1294     CURRENT_STACK16->es = GlobalHandleToSel16( GetTaskQueue16(0) );
1295 }
1296
1297
1298 /***********************************************************************
1299  *           GetCurrentTask   (KERNEL.36)
1300  */
1301 HTASK16 WINAPI GetCurrentTask(void)
1302 {
1303     return PROCESS_Current()->task;
1304 }
1305
1306 DWORD WINAPI WIN16_GetCurrentTask(void)
1307 {
1308     /* This is the version used by relay code; the first task is */
1309     /* returned in the high word of the result */
1310     return MAKELONG( GetCurrentTask(), hFirstTask );
1311 }
1312
1313
1314 /***********************************************************************
1315  *           GetCurrentPDB   (KERNEL.37)
1316  *
1317  * UNDOC: returns PSP of KERNEL in high word
1318  */
1319 DWORD WINAPI GetCurrentPDB16(void)
1320 {
1321     TDB *pTask;
1322
1323     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1324     return MAKELONG(pTask->hPDB, 0); /* FIXME */
1325 }
1326
1327
1328 /***********************************************************************
1329  *           GetCurPID16   (KERNEL.157)
1330  */
1331 DWORD WINAPI GetCurPID16( DWORD unused )
1332 {
1333     return 0;
1334 }
1335
1336
1337 /***********************************************************************
1338  *           GetInstanceData   (KERNEL.54)
1339  */
1340 INT16 WINAPI GetInstanceData16( HINSTANCE16 instance, WORD buffer, INT16 len )
1341 {
1342     char *ptr = (char *)GlobalLock16( instance );
1343     if (!ptr || !len) return 0;
1344     if ((int)buffer + len >= 0x10000) len = 0x10000 - buffer;
1345     memcpy( (char *)GlobalLock16(CURRENT_DS) + buffer, ptr + buffer, len );
1346     return len;
1347 }
1348
1349
1350 /***********************************************************************
1351  *           GetExeVersion   (KERNEL.105)
1352  */
1353 WORD WINAPI GetExeVersion16(void)
1354 {
1355     TDB *pTask;
1356
1357     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1358     return pTask->version;
1359 }
1360
1361
1362 /***********************************************************************
1363  *           SetErrorMode16   (KERNEL.107)
1364  */
1365 UINT16 WINAPI SetErrorMode16( UINT16 mode )
1366 {
1367     TDB *pTask;
1368     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1369     pTask->error_mode = mode;
1370     return SetErrorMode( mode );
1371 }
1372
1373
1374 /***********************************************************************
1375  *           GetDOSEnvironment   (KERNEL.131)
1376  */
1377 SEGPTR WINAPI GetDOSEnvironment16(void)
1378 {
1379     TDB *pTask;
1380
1381     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1382     return PTR_SEG_OFF_TO_SEGPTR( pTask->pdb.environment, 0 );
1383 }
1384
1385
1386 /***********************************************************************
1387  *           GetNumTasks   (KERNEL.152)
1388  */
1389 UINT16 WINAPI GetNumTasks16(void)
1390 {
1391     return nTaskCount;
1392 }
1393
1394
1395 /***********************************************************************
1396  *           GetTaskDS   (KERNEL.155)
1397  *
1398  * Note: this function apparently returns a DWORD with LOWORD == HIWORD.
1399  * I don't think we need to bother with this.
1400  */
1401 HINSTANCE16 WINAPI GetTaskDS16(void)
1402 {
1403     TDB *pTask;
1404
1405     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1406     return pTask->hInstance;
1407 }
1408
1409 /***********************************************************************
1410  *           GetDummyModuleHandleDS   (KERNEL.602)
1411  */
1412 WORD WINAPI GetDummyModuleHandleDS16(void)
1413 {
1414     TDB *pTask;
1415     WORD selector;
1416
1417     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1418     if (!(pTask->flags & TDBF_WIN32)) return 0;
1419     selector = GlobalHandleToSel16( pTask->hModule );
1420     CURRENT_DS = selector;
1421     return selector;
1422 }
1423
1424 /***********************************************************************
1425  *           IsTask   (KERNEL.320)
1426  */
1427 BOOL16 WINAPI IsTask16( HTASK16 hTask )
1428 {
1429     TDB *pTask;
1430
1431     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return FALSE;
1432     if (GlobalSize16( hTask ) < sizeof(TDB)) return FALSE;
1433     return (pTask->magic == TDB_MAGIC);
1434 }
1435
1436
1437 /***********************************************************************
1438  *           IsWinOldApTask16   (KERNEL.158)
1439  */
1440 BOOL16 WINAPI IsWinOldApTask16( HTASK16 hTask )
1441 {
1442     /* should return bit 0 of byte 0x48 in PSP */
1443     return FALSE;
1444 }
1445
1446 /***********************************************************************
1447  *           SetTaskSignalProc   (KERNEL.38)
1448  */
1449 FARPROC16 WINAPI SetTaskSignalProc( HTASK16 hTask, FARPROC16 proc )
1450 {
1451     TDB *pTask;
1452     FARPROC16 oldProc;
1453
1454     if (!hTask) hTask = GetCurrentTask();
1455     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return NULL;
1456     oldProc = pTask->userhandler;
1457     pTask->userhandler = proc;
1458     return oldProc;
1459 }
1460
1461 /***********************************************************************
1462  *           TASK_CallTaskSignalProc
1463  */
1464 /* ### start build ### */
1465 extern WORD CALLBACK TASK_CallTo16_word_wwwww(FARPROC16,WORD,WORD,WORD,WORD,WORD);
1466 /* ### stop build ### */
1467 void TASK_CallTaskSignalProc( UINT16 uCode, HANDLE16 hTaskOrModule )
1468 {
1469     TDB *pTask = (TDB *)GlobalLock16( GetCurrentTask() );
1470     if ( !pTask || !pTask->userhandler ) return;
1471
1472     TASK_CallTo16_word_wwwww( pTask->userhandler,
1473                               hTaskOrModule, uCode, 0,
1474                               pTask->hInstance, pTask->hQueue );
1475 }
1476
1477 /***********************************************************************
1478  *           SetSigHandler   (KERNEL.140)
1479  */
1480 WORD WINAPI SetSigHandler16( FARPROC16 newhandler, FARPROC16* oldhandler,
1481                            UINT16 *oldmode, UINT16 newmode, UINT16 flag )
1482 {
1483     FIXME_(task)("(%p,%p,%p,%d,%d), unimplemented.\n",
1484           newhandler,oldhandler,oldmode,newmode,flag );
1485
1486     if (flag != 1) return 0;
1487     if (!newmode) newhandler = NULL;  /* Default handler */
1488     if (newmode != 4)
1489     {
1490         TDB *pTask;
1491
1492         if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1493         if (oldmode) *oldmode = pTask->signal_flags;
1494         pTask->signal_flags = newmode;
1495         if (oldhandler) *oldhandler = pTask->sighandler;
1496         pTask->sighandler = newhandler;
1497     }
1498     return 0;
1499 }
1500
1501
1502 /***********************************************************************
1503  *           GlobalNotify   (KERNEL.154)
1504  *
1505  * Note that GlobalNotify does _not_ return the old NotifyProc
1506  * -- contrary to LocalNotify !!
1507  */
1508 VOID WINAPI GlobalNotify16( FARPROC16 proc )
1509 {
1510     TDB *pTask;
1511
1512     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
1513     pTask->discardhandler = proc;
1514 }
1515
1516
1517 /***********************************************************************
1518  *           GetExePtr   (KERNEL.133)
1519  */
1520 static inline HMODULE16 GetExePtrHelper( HANDLE16 handle, HTASK16 *hTask )
1521 {
1522     char *ptr;
1523     HANDLE16 owner;
1524
1525       /* Check for module handle */
1526
1527     if (!(ptr = GlobalLock16( handle ))) return 0;
1528     if (((NE_MODULE *)ptr)->magic == IMAGE_OS2_SIGNATURE) return handle;
1529
1530       /* Search for this handle inside all tasks */
1531
1532     *hTask = hFirstTask;
1533     while (*hTask)
1534     {
1535         TDB *pTask = (TDB *)GlobalLock16( *hTask );
1536         if ((*hTask == handle) ||
1537             (pTask->hInstance == handle) ||
1538             (pTask->hQueue == handle) ||
1539             (pTask->hPDB == handle)) return pTask->hModule;
1540         *hTask = pTask->hNext;
1541     }
1542
1543       /* Check the owner for module handle */
1544
1545     owner = FarGetOwner16( handle );
1546     if (!(ptr = GlobalLock16( owner ))) return 0;
1547     if (((NE_MODULE *)ptr)->magic == IMAGE_OS2_SIGNATURE) return owner;
1548
1549       /* Search for the owner inside all tasks */
1550
1551     *hTask = hFirstTask;
1552     while (*hTask)
1553     {
1554         TDB *pTask = (TDB *)GlobalLock16( *hTask );
1555         if ((*hTask == owner) ||
1556             (pTask->hInstance == owner) ||
1557             (pTask->hQueue == owner) ||
1558             (pTask->hPDB == owner)) return pTask->hModule;
1559         *hTask = pTask->hNext;
1560     }
1561
1562     return 0;
1563 }
1564
1565 HMODULE16 WINAPI WIN16_GetExePtr( HANDLE16 handle )
1566 {
1567     HTASK16 hTask = 0;
1568     HMODULE16 hModule = GetExePtrHelper( handle, &hTask );
1569     STACK16FRAME *frame = CURRENT_STACK16;
1570     frame->ecx = hModule;
1571     if (hTask) frame->es = hTask;
1572     return hModule;
1573 }
1574
1575 HMODULE16 WINAPI GetExePtr( HANDLE16 handle )
1576 {
1577     HTASK16 hTask = 0;
1578     return GetExePtrHelper( handle, &hTask );
1579 }
1580
1581
1582 /***********************************************************************
1583  *           TaskFirst   (TOOLHELP.63)
1584  */
1585 BOOL16 WINAPI TaskFirst16( TASKENTRY *lpte )
1586 {
1587     lpte->hNext = hFirstTask;
1588     return TaskNext16( lpte );
1589 }
1590
1591
1592 /***********************************************************************
1593  *           TaskNext   (TOOLHELP.64)
1594  */
1595 BOOL16 WINAPI TaskNext16( TASKENTRY *lpte )
1596 {
1597     TDB *pTask;
1598     INSTANCEDATA *pInstData;
1599
1600     TRACE_(toolhelp)("(%p): task=%04x\n", lpte, lpte->hNext );
1601     if (!lpte->hNext) return FALSE;
1602     pTask = (TDB *)GlobalLock16( lpte->hNext );
1603     if (!pTask || pTask->magic != TDB_MAGIC) return FALSE;
1604     pInstData = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN( pTask->hInstance, 0 );
1605     lpte->hTask         = lpte->hNext;
1606     lpte->hTaskParent   = pTask->hParent;
1607     lpte->hInst         = pTask->hInstance;
1608     lpte->hModule       = pTask->hModule;
1609     lpte->wSS           = SELECTOROF( pTask->teb->cur_stack );
1610     lpte->wSP           = OFFSETOF( pTask->teb->cur_stack );
1611     lpte->wStackTop     = pInstData->stacktop;
1612     lpte->wStackMinimum = pInstData->stackmin;
1613     lpte->wStackBottom  = pInstData->stackbottom;
1614     lpte->wcEvents      = pTask->nEvents;
1615     lpte->hQueue        = pTask->hQueue;
1616     strncpy( lpte->szModule, pTask->module_name, 8 );
1617     lpte->szModule[8]   = '\0';
1618     lpte->wPSPOffset    = 0x100;  /*??*/
1619     lpte->hNext         = pTask->hNext;
1620     return TRUE;
1621 }
1622
1623
1624 /***********************************************************************
1625  *           TaskFindHandle   (TOOLHELP.65)
1626  */
1627 BOOL16 WINAPI TaskFindHandle16( TASKENTRY *lpte, HTASK16 hTask )
1628 {
1629     lpte->hNext = hTask;
1630     return TaskNext16( lpte );
1631 }
1632
1633
1634 /***********************************************************************
1635  *           GetAppCompatFlags16   (KERNEL.354)
1636  */
1637 DWORD WINAPI GetAppCompatFlags16( HTASK16 hTask )
1638 {
1639     return GetAppCompatFlags( hTask );
1640 }
1641
1642
1643 /***********************************************************************
1644  *           GetAppCompatFlags32   (USER32.206)
1645  */
1646 DWORD WINAPI GetAppCompatFlags( HTASK hTask )
1647 {
1648     TDB *pTask;
1649
1650     if (!hTask) hTask = GetCurrentTask();
1651     if (!(pTask=(TDB *)GlobalLock16( (HTASK16)hTask ))) return 0;
1652     if (GlobalSize16(hTask) < sizeof(TDB)) return 0;
1653     return pTask->compat_flags;
1654 }