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 "syslevel.h"
  35 #include "debugtools.h"
  36 #include "dosexe.h"
  37 #include "services.h"
  38 #include "server.h"
  39
  40 DEFAULT_DEBUG_CHANNEL(task)
  41 DECLARE_DEBUG_CHANNEL(relay)
  42 DECLARE_DEBUG_CHANNEL(toolhelp)
  43
  44   /* Min. number of thunks allocated when creating a new segment */
  45 #define MIN_THUNKS  32
  46
  47   /* Pointer to function to switch to a larger stack */
  48 int (*IF1632_CallLargeStack)( int (*func)(), void *arg ) = NULL;
  49
  50 static THHOOK DefaultThhook = { 0 };
  51 THHOOK *pThhook = &DefaultThhook;
  52
  53 #define hCurrentTask (pThhook->CurTDB)
  54 #define hFirstTask   (pThhook->HeadTDB)
  55 #define hLockedTask  (pThhook->LockTDB)
  56
  57 static UINT16 nTaskCount = 0;
  58
  59
  60 /***********************************************************************
  61  *           TASK_InstallTHHook
  62  */
  63 void TASK_InstallTHHook( THHOOK *pNewThhook )
  64 {
  65      THHOOK *pOldThhook = pThhook;
  66
  67      pThhook = pNewThhook? pNewThhook : &DefaultThhook;
  68
  69      *pThhook = *pOldThhook;
  70 }
  71
  72 /***********************************************************************
  73  *           TASK_GetNextTask
  74  */
  75 HTASK16 TASK_GetNextTask( HTASK16 hTask )
  76 {
  77     TDB* pTask = (TDB*)GlobalLock16(hTask);
  78
  79     if (pTask->hNext) return pTask->hNext;
  80     return (hFirstTask != hTask) ? hFirstTask : 0;
  81 }
  82
  83 /***********************************************************************
  84  *           TASK_LinkTask
  85  */
  86 static void TASK_LinkTask( HTASK16 hTask )
  87 {
  88     HTASK16 *prevTask;
  89     TDB *pTask;
  90
  91     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
  92     prevTask = &hFirstTask;
  93     while (*prevTask)
  94     {
  95         TDB *prevTaskPtr = (TDB *)GlobalLock16( *prevTask );
  96         if (prevTaskPtr->priority >= pTask->priority) break;
  97         prevTask = &prevTaskPtr->hNext;
  98     }
  99     pTask->hNext = *prevTask;
 100     *prevTask = hTask;
 101     nTaskCount++;
 102 }
 103
 104
 105 /***********************************************************************
 106  *           TASK_UnlinkTask
 107  */
 108 static void TASK_UnlinkTask( HTASK16 hTask )
 109 {
 110     HTASK16 *prevTask;
 111     TDB *pTask;
 112
 113     prevTask = &hFirstTask;
 114     while (*prevTask && (*prevTask != hTask))
 115     {
 116         pTask = (TDB *)GlobalLock16( *prevTask );
 117         prevTask = &pTask->hNext;
 118     }
 119     if (*prevTask)
 120     {
 121         pTask = (TDB *)GlobalLock16( *prevTask );
 122         *prevTask = pTask->hNext;
 123         pTask->hNext = 0;
 124         nTaskCount--;
 125     }
 126 }
 127
 128
 129 /***********************************************************************
 130  *           TASK_CreateThunks
 131  *
 132  * Create a thunk free-list in segment 'handle', starting from offset 'offset'
 133  * and containing 'count' entries.
 134  */
 135 static void TASK_CreateThunks( HGLOBAL16 handle, WORD offset, WORD count )
 136 {
 137     int i;
 138     WORD free;
 139     THUNKS *pThunk;
 140
 141     pThunk = (THUNKS *)((BYTE *)GlobalLock16( handle ) + offset);
 142     pThunk->next = 0;
 143     pThunk->magic = THUNK_MAGIC;
 144     pThunk->free = (int)&pThunk->thunks - (int)pThunk;
 145     free = pThunk->free;
 146     for (i = 0; i < count-1; i++)
 147     {
 148         free += 8;  /* Offset of next thunk */
 149         pThunk->thunks[4*i] = free;
 150     }
 151     pThunk->thunks[4*i] = 0;  /* Last thunk */
 152 }
 153
 154
 155 /***********************************************************************
 156  *           TASK_AllocThunk
 157  *
 158  * Allocate a thunk for MakeProcInstance().
 159  */
 160 static SEGPTR TASK_AllocThunk( HTASK16 hTask )
 161 {
 162     TDB *pTask;
 163     THUNKS *pThunk;
 164     WORD sel, base;
 165
 166     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
 167     sel = pTask->hCSAlias;
 168     pThunk = &pTask->thunks;
 169     base = (int)pThunk - (int)pTask;
 170     while (!pThunk->free)
 171     {
 172         sel = pThunk->next;
 173         if (!sel)  /* Allocate a new segment */
 174         {
 175             sel = GLOBAL_Alloc( GMEM_FIXED, sizeof(THUNKS) + (MIN_THUNKS-1)*8,
 176                                 pTask->hPDB, TRUE, FALSE, FALSE );
 177             if (!sel) return (SEGPTR)0;
 178             TASK_CreateThunks( sel, 0, MIN_THUNKS );
 179             pThunk->next = sel;
 180         }
 181         pThunk = (THUNKS *)GlobalLock16( sel );
 182         base = 0;
 183     }
 184     base += pThunk->free;
 185     pThunk->free = *(WORD *)((BYTE *)pThunk + pThunk->free);
 186     return PTR_SEG_OFF_TO_SEGPTR( sel, base );
 187 }
 188
 189
 190 /***********************************************************************
 191  *           TASK_FreeThunk
 192  *
 193  * Free a MakeProcInstance() thunk.
 194  */
 195 static BOOL TASK_FreeThunk( HTASK16 hTask, SEGPTR thunk )
 196 {
 197     TDB *pTask;
 198     THUNKS *pThunk;
 199     WORD sel, base;
 200
 201     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
 202     sel = pTask->hCSAlias;
 203     pThunk = &pTask->thunks;
 204     base = (int)pThunk - (int)pTask;
 205     while (sel && (sel != HIWORD(thunk)))
 206     {
 207         sel = pThunk->next;
 208         pThunk = (THUNKS *)GlobalLock16( sel );
 209         base = 0;
 210     }
 211     if (!sel) return FALSE;
 212     *(WORD *)((BYTE *)pThunk + LOWORD(thunk) - base) = pThunk->free;
 213     pThunk->free = LOWORD(thunk) - base;
 214     return TRUE;
 215 }
 216
 217
 218 /***********************************************************************
 219  *           TASK_CallToStart
 220  *
 221  * 32-bit entry point for a new task. This function is responsible for
 222  * setting up the registers and jumping to the 16-bit entry point.
 223  */
 224 void TASK_CallToStart(void)
 225 {
 226     TDB *pTask = (TDB *)GlobalLock16( GetCurrentTask() );
 227     NE_MODULE *pModule = NE_GetPtr( pTask->hModule );
 228     SEGTABLEENTRY *pSegTable = NE_SEG_TABLE( pModule );
 229     CONTEXT86 context;
 230
 231     SYSLEVEL_EnterWin16Lock();
 232
 233     /* Add task to 16-bit scheduler pool if necessary */
 234     if ( hCurrentTask != GetCurrentTask() )
 235         TASK_Reschedule();
 236
 237     /* Registers at initialization must be:
 238      * ax   zero
 239      * bx   stack size in bytes
 240      * cx   heap size in bytes
 241      * si   previous app instance
 242      * di   current app instance
 243      * bp   zero
 244      * es   selector to the PSP
 245      * ds   dgroup of the application
 246      * ss   stack selector
 247      * sp   top of the stack
 248      */
 249
 250     memset( &context, 0, sizeof(context) );
 251     CS_reg(&context)  = GlobalHandleToSel16(pSegTable[pModule->cs - 1].hSeg);
 252     DS_reg(&context)  = GlobalHandleToSel16(pTask->hInstance);
 253     ES_reg(&context)  = pTask->hPDB;
 254     EIP_reg(&context) = pModule->ip;
 255     EBX_reg(&context) = pModule->stack_size;
 256     ECX_reg(&context) = pModule->heap_size;
 257     EDI_reg(&context) = pTask->hInstance;
 258     ESI_reg(&context) = pTask->hPrevInstance;
 259
 260     TRACE("Starting main program: cs:ip=%04lx:%04lx ds=%04lx ss:sp=%04x:%04x\n",
 261           CS_reg(&context), EIP_reg(&context), DS_reg(&context),
 262           SELECTOROF(pTask->teb->cur_stack),
 263           OFFSETOF(pTask->teb->cur_stack) );
 264
 265     Callbacks->CallRegisterShortProc( &context, 0 );
 266 }
 267
 268
 269 /***********************************************************************
 270  *           TASK_Create
 271  *
 272  * NOTE: This routine might be called by a Win32 thread. Thus, we need
 273  *       to be careful to protect global data structures. We do this
 274  *       by entering the Win16Lock while linking the task into the
 275  *       global task list.
 276  */
 277 BOOL TASK_Create( NE_MODULE *pModule, UINT16 cmdShow)
 278 {
 279     HTASK16 hTask;
 280     TDB *pTask;
 281     LPSTR cmd_line;
 282     char name[10];
 283     PDB *pdb32 = PROCESS_Current();
 284
 285       /* Allocate the task structure */
 286
 287     hTask = GLOBAL_Alloc( GMEM_FIXED | GMEM_ZEROINIT, sizeof(TDB),
 288                           pModule->self, FALSE, FALSE, FALSE );
 289     if (!hTask) return FALSE;
 290     pTask = (TDB *)GlobalLock16( hTask );
 291
 292     /* Fill the task structure */
 293
 294     pTask->nEvents       = 0;
 295     pTask->hSelf         = hTask;
 296     pTask->flags         = 0;
 297
 298     if (pModule->flags & NE_FFLAGS_WIN32)
 299         pTask->flags    |= TDBF_WIN32;
 300     if (pModule->lpDosTask)
 301         pTask->flags    |= TDBF_WINOLDAP;
 302
 303     pTask->hInstance     = pModule->self;
 304     pTask->hPrevInstance = 0;
 305     /* NOTE: for 16-bit tasks, the instance handles are updated later on
 306              in NE_InitProcess */
 307
 308     pTask->version       = pModule->expected_version;
 309     pTask->hModule       = pModule->self;
 310     pTask->hParent       = GetCurrentTask();
 311     pTask->magic         = TDB_MAGIC;
 312     pTask->nCmdShow      = cmdShow;
 313     pTask->teb           = NtCurrentTeb();
 314     pTask->curdrive      = DRIVE_GetCurrentDrive() | 0x80;
 315     strcpy( pTask->curdir, "\\" );
 316     lstrcpynA( pTask->curdir + 1, DRIVE_GetDosCwd( DRIVE_GetCurrentDrive() ),
 317                  sizeof(pTask->curdir) - 1 );
 318
 319       /* Create the thunks block */
 320
 321     TASK_CreateThunks( hTask, (int)&pTask->thunks - (int)pTask, 7 );
 322
 323       /* Copy the module name */
 324
 325     GetModuleName16( pModule->self, name, sizeof(name) );
 326     strncpy( pTask->module_name, name, sizeof(pTask->module_name) );
 327
 328       /* Allocate a selector for the PDB */
 329
 330     pTask->hPDB = GLOBAL_CreateBlock( GMEM_FIXED, &pTask->pdb, sizeof(PDB16),
 331                                     pModule->self, FALSE, FALSE, FALSE, NULL );
 332
 333       /* Fill the PDB */
 334
 335     pTask->pdb.int20 = 0x20cd;
 336     pTask->pdb.dispatcher[0] = 0x9a;  /* ljmp */
 337     PUT_DWORD(&pTask->pdb.dispatcher[1], (DWORD)NE_GetEntryPoint(
 338            GetModuleHandle16("KERNEL"), 102 ));  /* KERNEL.102 is DOS3Call() */
 339     pTask->pdb.savedint22 = INT_GetPMHandler( 0x22 );
 340     pTask->pdb.savedint23 = INT_GetPMHandler( 0x23 );
 341     pTask->pdb.savedint24 = INT_GetPMHandler( 0x24 );
 342     pTask->pdb.fileHandlesPtr =
 343         PTR_SEG_OFF_TO_SEGPTR( GlobalHandleToSel16(pTask->hPDB),
 344                                (int)&((PDB16 *)0)->fileHandles );
 345     pTask->pdb.hFileHandles = 0;
 346     memset( pTask->pdb.fileHandles, 0xff, sizeof(pTask->pdb.fileHandles) );
 347     pTask->pdb.environment    = pdb32->env_db->env_sel;
 348     pTask->pdb.nbFiles        = 20;
 349
 350     /* Fill the command line */
 351
 352     cmd_line = pdb32->env_db->cmd_line;
 353     while (*cmd_line && (*cmd_line != ' ') && (*cmd_line != '\t')) cmd_line++;
 354     while ((*cmd_line == ' ') || (*cmd_line == '\t')) cmd_line++;
 355     lstrcpynA( pTask->pdb.cmdLine+1, cmd_line, sizeof(pTask->pdb.cmdLine)-1);
 356     pTask->pdb.cmdLine[0] = strlen( pTask->pdb.cmdLine + 1 );
 357
 358       /* Get the compatibility flags */
 359
 360     pTask->compat_flags = GetProfileIntA( "Compatibility", name, 0 );
 361
 362       /* Allocate a code segment alias for the TDB */
 363
 364     pTask->hCSAlias = GLOBAL_CreateBlock( GMEM_FIXED, (void *)pTask,
 365                                           sizeof(TDB), pTask->hPDB, TRUE,
 366                                           FALSE, FALSE, NULL );
 367
 368       /* Set the owner of the environment block */
 369
 370     FarSetOwner16( pTask->pdb.environment, pTask->hPDB );
 371
 372       /* Default DTA overwrites command-line */
 373
 374     pTask->dta = PTR_SEG_OFF_TO_SEGPTR( pTask->hPDB,
 375                                 (int)&pTask->pdb.cmdLine - (int)&pTask->pdb );
 376
 377     /* Create scheduler event for 16-bit tasks */
 378
 379     if ( !(pTask->flags & TDBF_WIN32) )
 380     {
 381         pTask->hEvent = CreateEventA( NULL, TRUE, FALSE, NULL );
 382         pTask->hEvent = ConvertToGlobalHandle( pTask->hEvent );
 383     }
 384
 385     /* Enter task handle into thread and process */
 386
 387     pTask->teb->htask16 = pTask->teb->process->task = hTask;
 388     TRACE("module='%s' cmdline='%s' task=%04x\n", name, cmd_line, hTask );
 389
 390     /* Add the task to the linked list */
 391
 392     SYSLEVEL_EnterWin16Lock();
 393     TASK_LinkTask( hTask );
 394     SYSLEVEL_LeaveWin16Lock();
 395
 396     return TRUE;
 397 }
 398
 399 /***********************************************************************
 400  *           TASK_DeleteTask
 401  */
 402 static void TASK_DeleteTask( HTASK16 hTask )
 403 {
 404     TDB *pTask;
 405     HGLOBAL16 hPDB;
 406
 407     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 408     hPDB = pTask->hPDB;
 409
 410     pTask->magic = 0xdead; /* invalidate signature */
 411
 412     /* Delete the Win32 part of the task */
 413
 414 /*    PROCESS_FreePDB( pTask->teb->process ); FIXME */
 415 /*    K32OBJ_DecCount( &pTask->teb->header ); FIXME */
 416
 417     /* Free the selector aliases */
 418
 419     GLOBAL_FreeBlock( pTask->hCSAlias );
 420     GLOBAL_FreeBlock( pTask->hPDB );
 421
 422     /* Free the task module */
 423
 424     FreeModule16( pTask->hModule );
 425
 426     /* Free the task structure itself */
 427
 428     GlobalFree16( hTask );
 429
 430     /* Free all memory used by this task (including the 32-bit stack, */
 431     /* the environment block and the thunk segments). */
 432
 433     GlobalFreeAll16( hPDB );
 434 }
 435
 436 /***********************************************************************
 437  *           TASK_KillTask
 438  */
 439 void TASK_KillTask( HTASK16 hTask )
 440 {
 441     TDB *pTask;
 442
 443     /* Enter the Win16Lock to protect global data structures */
 444     SYSLEVEL_EnterWin16Lock();
 445
 446     if ( !hTask ) hTask = GetCurrentTask();
 447     pTask = (TDB *)GlobalLock16( hTask );
 448     if ( !pTask )
 449     {
 450         SYSLEVEL_LeaveWin16Lock();
 451         return;
 452     }
 453
 454     TRACE("Killing task %04x\n", hTask );
 455
 456 #ifdef MZ_SUPPORTED
 457 {
 458     /* Kill DOS VM task */
 459     NE_MODULE *pModule = NE_GetPtr( pTask->hModule );
 460     if ( pModule->lpDosTask )
 461         MZ_KillModule( pModule->lpDosTask );
 462 }
 463 #endif
 464
 465     /* Perform USER cleanup */
 466
 467     TASK_CallTaskSignalProc( USIG16_TERMINATION, hTask );
 468     PROCESS_CallUserSignalProc( USIG_PROCESS_EXIT, 0, 0 );
 469     PROCESS_CallUserSignalProc( USIG_THREAD_EXIT, GetCurrentThreadId(), 0 );
 470     PROCESS_CallUserSignalProc( USIG_PROCESS_DESTROY, 0, 0 );
 471
 472     if (nTaskCount <= 1)
 473     {
 474         TRACE("this is the last task, exiting\n" );
 475         ExitKernel16();
 476     }
 477
 478     /* FIXME: Hack! Send a message to the initial task so that
 479      * the GetMessage wakes up and the initial task can check whether
 480      * it is the only remaining one and terminate itself ...
 481      * The initial task should probably install hooks or something
 482      * to get informed about task termination :-/
 483      */
 484     Callout.PostAppMessage16( PROCESS_Initial()->task, WM_NULL, 0, 0 );
 485
 486     /* Remove the task from the list to be sure we never switch back to it */
 487     TASK_UnlinkTask( hTask );
 488     if( nTaskCount )
 489     {
 490         TDB* p = (TDB *)GlobalLock16( hFirstTask );
 491         while( p )
 492         {
 493             if( p->hYieldTo == hTask ) p->hYieldTo = 0;
 494             p = (TDB *)GlobalLock16( p->hNext );
 495         }
 496     }
 497
 498     pTask->nEvents = 0;
 499
 500     if ( hLockedTask == hTask )
 501         hLockedTask = 0;
 502
 503     TASK_DeleteTask( hTask );
 504
 505     /* When deleting the current task ... */
 506     if ( hTask == hCurrentTask )
 507     {
 508         DWORD lockCount;
 509
 510         /* ... schedule another one ... */
 511         TASK_Reschedule();
 512
 513         /* ... and completely release the Win16Lock, just in case. */
 514         ReleaseThunkLock( &lockCount );
 515
 516         return;
 517     }
 518
 519     SYSLEVEL_LeaveWin16Lock();
 520 }
 521
 522 /***********************************************************************
 523  *           TASK_Reschedule
 524  *
 525  * This is where all the magic of task-switching happens!
 526  *
 527  * 16-bit Windows performs non-preemptive (cooperative) multitasking.
 528  * This means that each 16-bit task runs until it voluntarily yields
 529  * control, at which point the scheduler gets active and selects the
 530  * next task to run.
 531  *
 532  * In Wine, all processes, even 16-bit ones, are scheduled preemptively
 533  * by the standard scheduler of the underlying OS.  As many 16-bit apps
 534  * *rely* on the behaviour of the Windows scheduler, however, we have
 535  * to simulate that behaviour.
 536  *
 537  * This is achieved as follows: every 16-bit task is at time (except
 538  * during task creation and deletion) in one of two states: either it
 539  * is the one currently running, then the global variable hCurrentTask
 540  * contains its task handle, or it is not currently running, then it
 541  * is blocked on a special scheduler event, a global handle to which
 542  * is stored in the task struct.
 543  *
 544  * When the current task yields control, this routine gets called. Its
 545  * purpose is to determine the next task to be active, signal the
 546  * scheduler event of that task, and then put the current task to sleep
 547  * waiting for *its* scheduler event to get signalled again.
 548  *
 549  * This routine can get called in a few other special situations as well:
 550  *
 551  * - On creation of a 16-bit task, the Unix process executing the task
 552  *   calls TASK_Reschedule once it has completed its initialization.
 553  *   At this point, the task needs to be blocked until its scheduler
 554  *   event is signalled the first time (this will be done by the parent
 555  *   process to get the task up and running).
 556  *
 557  * - When the task currently running terminates itself, this routine gets
 558  *   called and has to schedule another task, *without* blocking the
 559  *   terminating task.
 560  *
 561  * - When a 32-bit thread posts an event for a 16-bit task, it might be
 562  *   the case that *no* 16-bit task is currently running.  In this case
 563  *   the task that has now an event pending is to be scheduled.
 564  *
 565  */
 566 void TASK_Reschedule(void)
 567 {
 568     TDB *pOldTask = NULL, *pNewTask = NULL;
 569     HTASK16 hOldTask = 0, hNewTask = 0;
 570     enum { MODE_YIELD, MODE_SLEEP, MODE_WAKEUP } mode;
 571     DWORD lockCount;
 572
 573     SYSLEVEL_EnterWin16Lock();
 574
 575     /* Check what we need to do */
 576     hOldTask = GetCurrentTask();
 577     pOldTask = (TDB *)GlobalLock16( hOldTask );
 578     TRACE( "entered with hCurrentTask %04x by hTask %04x (pid %ld)\n",
 579            hCurrentTask, hOldTask, (long) getpid() );
 580
 581     if ( pOldTask && THREAD_IsWin16( NtCurrentTeb() ) )
 582     {
 583         /* We are called by an active (non-deleted) 16-bit task */
 584
 585         /* If we don't even have a current task, or else the current
 586            task has yielded, we'll need to schedule a new task and
 587            (possibly) put the calling task to sleep.  Otherwise, we
 588            only block the caller. */
 589
 590         if ( !hCurrentTask || hCurrentTask == hOldTask )
 591             mode = MODE_YIELD;
 592         else
 593             mode = MODE_SLEEP;
 594     }
 595     else
 596     {
 597         /* We are called by a deleted 16-bit task or a 32-bit thread */
 598
 599         /* The only situation where we need to do something is if we
 600            now do not have a current task.  Then, we'll need to wake up
 601            some task that has events pending. */
 602
 603         if ( !hCurrentTask || hCurrentTask == hOldTask )
 604             mode = MODE_WAKEUP;
 605         else
 606         {
 607             /* nothing to do */
 608             SYSLEVEL_LeaveWin16Lock();
 609             return;
 610         }
 611     }
 612
 613     /* Find a task to yield to: check for DirectedYield() */
 614     if ( mode == MODE_YIELD && pOldTask && pOldTask->hYieldTo )
 615     {
 616         hNewTask = pOldTask->hYieldTo;
 617         pNewTask = (TDB *)GlobalLock16( hNewTask );
 618         if( !pNewTask || !pNewTask->nEvents) hNewTask = 0;
 619         pOldTask->hYieldTo = 0;
 620     }
 621
 622     /* Find a task to yield to: check for pending events */
 623     if ( (mode == MODE_YIELD || mode == MODE_WAKEUP) && !hNewTask )
 624     {
 625         hNewTask = hFirstTask;
 626         while (hNewTask)
 627         {
 628             pNewTask = (TDB *)GlobalLock16( hNewTask );
 629
 630             TRACE( "\ttask = %04x, events = %i\n", hNewTask, pNewTask->nEvents );
 631
 632             if (pNewTask->nEvents) break;
 633             hNewTask = pNewTask->hNext;
 634         }
 635         if (hLockedTask && (hNewTask != hLockedTask)) hNewTask = 0;
 636     }
 637
 638     /* If we are still the task with highest priority, just return ... */
 639     if ( mode == MODE_YIELD && hNewTask == hCurrentTask )
 640     {
 641         TRACE("returning to the current task (%04x)\n", hCurrentTask );
 642         SYSLEVEL_LeaveWin16Lock();
 643
 644         /* Allow Win32 threads to thunk down even while a Win16 task is
 645            in a tight PeekMessage() or Yield() loop ... */
 646         ReleaseThunkLock( &lockCount );
 647         RestoreThunkLock( lockCount );
 648         return;
 649     }
 650
 651     /* If no task to yield to found, suspend 16-bit scheduler ... */
 652     if ( mode == MODE_YIELD && !hNewTask )
 653     {
 654         TRACE("No currently active task\n");
 655         hCurrentTask = 0;
 656     }
 657
 658     /* If we found a task to wake up, do it ... */
 659     if ( (mode == MODE_YIELD || mode == MODE_WAKEUP) && hNewTask )
 660     {
 661         TRACE("Switching to task %04x (%.8s)\n",
 662                       hNewTask, pNewTask->module_name );
 663
 664         pNewTask->priority++;
 665         TASK_UnlinkTask( hNewTask );
 666         TASK_LinkTask( hNewTask );
 667         pNewTask->priority--;
 668
 669         hCurrentTask = hNewTask;
 670         SetEvent( pNewTask->hEvent );
 671
 672         /* This is set just in case some app reads it ... */
 673         pNewTask->ss_sp = pNewTask->teb->cur_stack;
 674     }
 675
 676     /* If we need to put the current task to sleep, do it ... */
 677     if ( (mode == MODE_YIELD || mode == MODE_SLEEP) && hOldTask != hCurrentTask )
 678     {
 679         ResetEvent( pOldTask->hEvent );
 680
 681         ReleaseThunkLock( &lockCount );
 682         SYSLEVEL_CheckNotLevel( 1 );
 683         WaitForSingleObject( pOldTask->hEvent, INFINITE );
 684         RestoreThunkLock( lockCount );
 685     }
 686
 687     SYSLEVEL_LeaveWin16Lock();
 688 }
 689
 690 /***********************************************************************
 691  *           InitTask  (KERNEL.91)
 692  *
 693  * Called by the application startup code.
 694  */
 695 void WINAPI InitTask16( CONTEXT86 *context )
 696 {
 697     TDB *pTask;
 698     INSTANCEDATA *pinstance;
 699     SEGPTR ptr;
 700
 701     EAX_reg(context) = 0;
 702     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
 703
 704     /* Note: we need to trust that BX/CX contain the stack/heap sizes,
 705        as some apps, notably Visual Basic apps, *modify* the heap/stack
 706        size of the instance data segment before calling InitTask() */
 707
 708     /* Initialize the INSTANCEDATA structure */
 709     pinstance = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN(CURRENT_DS, 0);
 710     pinstance->stackmin    = OFFSETOF( pTask->teb->cur_stack );
 711     pinstance->stackbottom = pinstance->stackmin; /* yup, that's right. Confused me too. */
 712     pinstance->stacktop    = ( pinstance->stackmin > BX_reg(context)?
 713                                pinstance->stackmin - BX_reg(context) : 0 ) + 150;
 714
 715     /* Initialize the local heap */
 716     if ( CX_reg(context) )
 717         LocalInit16( pTask->hInstance, 0, CX_reg(context) );
 718
 719     /* Initialize implicitly loaded DLLs */
 720     NE_InitializeDLLs( pTask->hModule );
 721     NE_DllProcessAttach( pTask->hModule );
 722
 723     /* Registers on return are:
 724      * ax     1 if OK, 0 on error
 725      * cx     stack limit in bytes
 726      * dx     cmdShow parameter
 727      * si     instance handle of the previous instance
 728      * di     instance handle of the new task
 729      * es:bx  pointer to command-line inside PSP
 730      *
 731      * 0 (=%bp) is pushed on the stack
 732      */
 733     ptr = stack16_push( sizeof(WORD) );
 734     *(WORD *)PTR_SEG_TO_LIN(ptr) = 0;
 735     ESP_reg(context) -= 2;
 736
 737     EAX_reg(context) = 1;
 738
 739     if (!pTask->pdb.cmdLine[0]) EBX_reg(context) = 0x80;
 740     else
 741     {
 742         LPBYTE p = &pTask->pdb.cmdLine[1];
 743         while ((*p == ' ') || (*p == '\t')) p++;
 744         EBX_reg(context) = 0x80 + (p - pTask->pdb.cmdLine);
 745     }
 746     ECX_reg(context) = pinstance->stacktop;
 747     EDX_reg(context) = pTask->nCmdShow;
 748     ESI_reg(context) = (DWORD)pTask->hPrevInstance;
 749     EDI_reg(context) = (DWORD)pTask->hInstance;
 750     ES_reg (context) = (WORD)pTask->hPDB;
 751 }
 752
 753
 754 /***********************************************************************
 755  *           WaitEvent  (KERNEL.30)
 756  */
 757 BOOL16 WINAPI WaitEvent16( HTASK16 hTask )
 758 {
 759     TDB *pTask;
 760
 761     if (!hTask) hTask = GetCurrentTask();
 762     pTask = (TDB *)GlobalLock16( hTask );
 763
 764     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 765     {
 766         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 767         return TRUE;
 768     }
 769
 770     if (pTask->nEvents > 0)
 771     {
 772         pTask->nEvents--;
 773         return FALSE;
 774     }
 775     TASK_Reschedule();
 776
 777     /* When we get back here, we have an event */
 778
 779     if (pTask->nEvents > 0) pTask->nEvents--;
 780     return TRUE;
 781 }
 782
 783
 784 /***********************************************************************
 785  *           PostEvent  (KERNEL.31)
 786  */
 787 void WINAPI PostEvent16( HTASK16 hTask )
 788 {
 789     TDB *pTask;
 790
 791     if (!hTask) hTask = GetCurrentTask();
 792     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 793
 794     if ( !THREAD_IsWin16( pTask->teb ) )
 795     {
 796         FIXME("called for Win32 thread (%04x)!\n", pTask->teb->teb_sel );
 797         return;
 798     }
 799
 800     pTask->nEvents++;
 801
 802     /* If we are a 32-bit task, we might need to wake up the 16-bit scheduler */
 803     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 804         TASK_Reschedule();
 805 }
 806
 807
 808 /***********************************************************************
 809  *           SetPriority  (KERNEL.32)
 810  */
 811 void WINAPI SetPriority16( HTASK16 hTask, INT16 delta )
 812 {
 813     TDB *pTask;
 814     INT16 newpriority;
 815
 816     if (!hTask) hTask = GetCurrentTask();
 817     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 818     newpriority = pTask->priority + delta;
 819     if (newpriority < -32) newpriority = -32;
 820     else if (newpriority > 15) newpriority = 15;
 821
 822     pTask->priority = newpriority + 1;
 823     TASK_UnlinkTask( hTask );
 824     TASK_LinkTask( hTask );
 825     pTask->priority--;
 826 }
 827
 828
 829 /***********************************************************************
 830  *           LockCurrentTask  (KERNEL.33)
 831  */
 832 HTASK16 WINAPI LockCurrentTask16( BOOL16 bLock )
 833 {
 834     if (bLock) hLockedTask = GetCurrentTask();
 835     else hLockedTask = 0;
 836     return hLockedTask;
 837 }
 838
 839
 840 /***********************************************************************
 841  *           IsTaskLocked  (KERNEL.122)
 842  */
 843 HTASK16 WINAPI IsTaskLocked16(void)
 844 {
 845     return hLockedTask;
 846 }
 847
 848
 849 /***********************************************************************
 850  *           OldYield  (KERNEL.117)
 851  */
 852 void WINAPI OldYield16(void)
 853 {
 854     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 855
 856     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 857     {
 858         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 859         return;
 860     }
 861
 862     if (pCurTask) pCurTask->nEvents++;  /* Make sure we get back here */
 863     TASK_Reschedule();
 864     if (pCurTask) pCurTask->nEvents--;
 865 }
 866
 867 /***********************************************************************
 868  *           WIN32_OldYield16  (KERNEL.447)
 869  */
 870 void WINAPI WIN32_OldYield16(void)
 871 {
 872    DWORD count;
 873
 874    ReleaseThunkLock(&count);
 875    RestoreThunkLock(count);
 876 }
 877
 878 /***********************************************************************
 879  *           DirectedYield  (KERNEL.150)
 880  */
 881 void WINAPI DirectedYield16( HTASK16 hTask )
 882 {
 883     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 884
 885     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 886     {
 887         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 888         return;
 889     }
 890
 891     TRACE("%04x: DirectedYield(%04x)\n", pCurTask->hSelf, hTask );
 892
 893     pCurTask->hYieldTo = hTask;
 894     OldYield16();
 895
 896     TRACE("%04x: back from DirectedYield(%04x)\n", pCurTask->hSelf, hTask );
 897 }
 898
 899 /***********************************************************************
 900  *           Yield16  (KERNEL.29)
 901  */
 902 void WINAPI Yield16(void)
 903 {
 904     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 905
 906     if (pCurTask) pCurTask->hYieldTo = 0;
 907     if (pCurTask && pCurTask->hQueue) Callout.UserYield16();
 908     else OldYield16();
 909 }
 910
 911 /***********************************************************************
 912  *           KERNEL_490  (KERNEL.490)
 913  */
 914 HTASK16 WINAPI KERNEL_490( HTASK16 someTask )
 915 {
 916     if ( !someTask ) return 0;
 917
 918     FIXME("(%04x): stub\n", someTask );
 919     return 0;
 920 }
 921
 922 /***********************************************************************
 923  *           MakeProcInstance16  (KERNEL.51)
 924  */
 925 FARPROC16 WINAPI MakeProcInstance16( FARPROC16 func, HANDLE16 hInstance )
 926 {
 927     BYTE *thunk,*lfunc;
 928     SEGPTR thunkaddr;
 929
 930     if (!func) {
 931       ERR("Ouch ! MakeProcInstance called with func == NULL !\n");
 932       return (FARPROC16)0; /* Windows seems to do the same */
 933     }
 934     if ( GetTaskDS16() !=hInstance )
 935     {
 936         ERR("Problem with hInstance? Got %04x, using %04x instead\n",
 937                    hInstance,GetTaskDS16());
 938         hInstance = GetTaskDS16();
 939     }
 940     if (!hInstance) hInstance = CURRENT_DS;
 941     thunkaddr = TASK_AllocThunk( GetCurrentTask() );
 942     if (!thunkaddr) return (FARPROC16)0;
 943     thunk = PTR_SEG_TO_LIN( thunkaddr );
 944     lfunc = PTR_SEG_TO_LIN( func );
 945
 946     TRACE("(%08lx,%04x): got thunk %08lx\n",
 947           (DWORD)func, hInstance, (DWORD)thunkaddr );
 948     if (((lfunc[0]==0x8c) && (lfunc[1]==0xd8)) ||
 949         ((lfunc[0]==0x1e) && (lfunc[1]==0x58))
 950     ) {
 951         FIXME("thunk would be useless for %p, overwriting with nop;nop;\n", func );
 952         lfunc[0]=0x90; /* nop */
 953         lfunc[1]=0x90; /* nop */
 954     }
 955
 956     *thunk++ = 0xb8;    /* movw instance, %ax */
 957     *thunk++ = (BYTE)(hInstance & 0xff);
 958     *thunk++ = (BYTE)(hInstance >> 8);
 959     *thunk++ = 0xea;    /* ljmp func */
 960     *(DWORD *)thunk = (DWORD)func;
 961     return (FARPROC16)thunkaddr;
 962 }
 963
 964
 965 /***********************************************************************
 966  *           FreeProcInstance16  (KERNEL.52)
 967  */
 968 void WINAPI FreeProcInstance16( FARPROC16 func )
 969 {
 970     TRACE("(%08lx)\n", (DWORD)func );
 971     TASK_FreeThunk( GetCurrentTask(), (SEGPTR)func );
 972 }
 973
 974 /**********************************************************************
 975  *          TASK_GetCodeSegment
 976  *
 977  * Helper function for GetCodeHandle/GetCodeInfo: Retrieve the module
 978  * and logical segment number of a given code segment.
 979  *
 980  * 'proc' either *is* already a pair of module handle and segment number,
 981  * in which case there's nothing to do.  Otherwise, it is a pointer to
 982  * a function, and we need to retrieve the code segment.  If the pointer
 983  * happens to point to a thunk, we'll retrieve info about the code segment
 984  * where the function pointed to by the thunk resides, not the thunk itself.
 985  *
 986  * FIXME: if 'proc' is a SNOOP16 return stub, we should retrieve info about
 987  *        the function the snoop code will return to ...
 988  *
 989  */
 990 static BOOL TASK_GetCodeSegment( FARPROC16 proc, NE_MODULE **ppModule,
 991                                  SEGTABLEENTRY **ppSeg, int *pSegNr )
 992 {
 993     NE_MODULE *pModule = NULL;
 994     SEGTABLEENTRY *pSeg = NULL;
 995     int segNr;
 996
 997     /* Try pair of module handle / segment number */
 998     pModule = (NE_MODULE *) GlobalLock16( HIWORD( proc ) );
 999     if ( pModule && pModule->magic == IMAGE_OS2_SIGNATURE )
1000     {
1001         segNr = LOWORD( proc );
1002         if ( segNr && segNr <= pModule->seg_count )
1003             pSeg = NE_SEG_TABLE( pModule ) + segNr-1;
1004     }
1005
1006     /* Try thunk or function */
1007     else
1008     {
1009         BYTE *thunk = (BYTE *)PTR_SEG_TO_LIN( proc );
1010         WORD selector;
1011
1012         if ((thunk[0] == 0xb8) && (thunk[3] == 0xea))
1013             selector = thunk[6] + (thunk[7] << 8);
1014         else
1015             selector = HIWORD( proc );
1016
1017         pModule = NE_GetPtr( GlobalHandle16( selector ) );
1018         pSeg = pModule? NE_SEG_TABLE( pModule ) : NULL;
1019
1020         if ( pModule )
1021             for ( segNr = 1; segNr <= pModule->seg_count; segNr++, pSeg++ )
1022                 if ( GlobalHandleToSel16(pSeg->hSeg) == selector )
1023                     break;
1024
1025         if ( pModule && segNr > pModule->seg_count )
1026             pSeg = NULL;
1027     }
1028
1029     /* Abort if segment not found */
1030
1031     if ( !pModule || !pSeg )
1032         return FALSE;
1033
1034     /* Return segment data */
1035
1036     if ( ppModule ) *ppModule = pModule;
1037     if ( ppSeg    ) *ppSeg    = pSeg;
1038     if ( pSegNr   ) *pSegNr   = segNr;
1039
1040     return TRUE;
1041 }
1042
1043 /**********************************************************************
1044  *          GetCodeHandle    (KERNEL.93)
1045  */
1046 HANDLE16 WINAPI GetCodeHandle16( FARPROC16 proc )
1047 {
1048     SEGTABLEENTRY *pSeg;
1049
1050     if ( !TASK_GetCodeSegment( proc, NULL, &pSeg, NULL ) )
1051         return (HANDLE16)0;
1052
1053     return pSeg->hSeg;
1054 }
1055
1056 /**********************************************************************
1057  *          GetCodeInfo    (KERNEL.104)
1058  */
1059 BOOL16 WINAPI GetCodeInfo16( FARPROC16 proc, SEGINFO *segInfo )
1060 {
1061     NE_MODULE *pModule;
1062     SEGTABLEENTRY *pSeg;
1063     int segNr;
1064
1065     if ( !TASK_GetCodeSegment( proc, &pModule, &pSeg, &segNr ) )
1066         return FALSE;
1067
1068     /* Fill in segment information */
1069
1070     segInfo->offSegment = pSeg->filepos;
1071     segInfo->cbSegment  = pSeg->size;
1072     segInfo->flags      = pSeg->flags;
1073     segInfo->cbAlloc    = pSeg->minsize;
1074     segInfo->h          = pSeg->hSeg;
1075     segInfo->alignShift = pModule->alignment;
1076
1077     if ( segNr == pModule->dgroup )
1078         segInfo->cbAlloc += pModule->heap_size + pModule->stack_size;
1079
1080     /* Return module handle in %es */
1081
1082     CURRENT_STACK16->es = GlobalHandleToSel16( pModule->self );
1083
1084     return TRUE;
1085 }
1086
1087
1088 /**********************************************************************
1089  *          DefineHandleTable16    (KERNEL.94)
1090  */
1091 BOOL16 WINAPI DefineHandleTable16( WORD wOffset )
1092 {
1093     return TRUE;  /* FIXME */
1094 }
1095
1096
1097 /***********************************************************************
1098  *           SetTaskQueue  (KERNEL.34)
1099  */
1100 HQUEUE16 WINAPI SetTaskQueue16( HTASK16 hTask, HQUEUE16 hQueue )
1101 {
1102     HQUEUE16 hPrev;
1103     TDB *pTask;
1104
1105     if (!hTask) hTask = GetCurrentTask();
1106     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
1107
1108     hPrev = pTask->hQueue;
1109     pTask->hQueue = hQueue;
1110
1111     return hPrev;
1112 }
1113
1114
1115 /***********************************************************************
1116  *           GetTaskQueue  (KERNEL.35)
1117  */
1118 HQUEUE16 WINAPI GetTaskQueue16( HTASK16 hTask )
1119 {
1120     TDB *pTask;
1121
1122     if (!hTask) hTask = GetCurrentTask();
1123     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
1124     return pTask->hQueue;
1125 }
1126
1127 /***********************************************************************
1128  *           SetThreadQueue  (KERNEL.463)
1129  */
1130 HQUEUE16 WINAPI SetThreadQueue16( DWORD thread, HQUEUE16 hQueue )
1131 {
1132     TEB *teb = thread? THREAD_IdToTEB( thread ) : NtCurrentTeb();
1133     HQUEUE16 oldQueue = teb? teb->queue : 0;
1134
1135     if ( teb )
1136     {
1137         teb->queue = hQueue;
1138
1139         if ( GetTaskQueue16( teb->process->task ) == oldQueue )
1140             SetTaskQueue16( teb->process->task, hQueue );
1141     }
1142
1143     return oldQueue;
1144 }
1145
1146 /***********************************************************************
1147  *           GetThreadQueue  (KERNEL.464)
1148  */
1149 HQUEUE16 WINAPI GetThreadQueue16( DWORD thread )
1150 {
1151     TEB *teb = NULL;
1152     if ( !thread )
1153         teb = NtCurrentTeb();
1154     else if ( HIWORD(thread) )
1155         teb = THREAD_IdToTEB( thread );
1156     else if ( IsTask16( (HTASK16)thread ) )
1157         teb = ((TDB *)GlobalLock16( (HANDLE16)thread ))->teb;
1158
1159     return (HQUEUE16)(teb? teb->queue : 0);
1160 }
1161
1162 /***********************************************************************
1163  *           SetFastQueue  (KERNEL.624)
1164  */
1165 VOID WINAPI SetFastQueue16( DWORD thread, HANDLE hQueue )
1166 {
1167     TEB *teb = NULL;
1168     if ( !thread )
1169         teb = NtCurrentTeb();
1170     else if ( HIWORD(thread) )
1171         teb = THREAD_IdToTEB( thread );
1172     else if ( IsTask16( (HTASK16)thread ) )
1173         teb = ((TDB *)GlobalLock16( (HANDLE16)thread ))->teb;
1174
1175     if ( teb ) teb->queue = (HQUEUE16) hQueue;
1176 }
1177
1178 /***********************************************************************
1179  *           GetFastQueue  (KERNEL.625)
1180  */
1181 HANDLE WINAPI GetFastQueue16( void )
1182 {
1183     TEB *teb = NtCurrentTeb();
1184     if (!teb) return 0;
1185
1186     if (!teb->queue)
1187         Callout.InitThreadInput16( 0, THREAD_IsWin16(teb)? 4 : 5 );
1188
1189     if (!teb->queue)
1190         FIXME("(): should initialize thread-local queue, expect failure!\n" );
1191
1192     return (HANDLE)teb->queue;
1193 }
1194
1195 /***********************************************************************
1196  *           SwitchStackTo   (KERNEL.108)
1197  */
1198 void WINAPI SwitchStackTo16( WORD seg, WORD ptr, WORD top )
1199 {
1200     TDB *pTask;
1201     STACK16FRAME *oldFrame, *newFrame;
1202     INSTANCEDATA *pData;
1203     UINT16 copySize;
1204
1205     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
1206     if (!(pData = (INSTANCEDATA *)GlobalLock16( seg ))) return;
1207     TRACE("old=%04x:%04x new=%04x:%04x\n",
1208           SELECTOROF( pTask->teb->cur_stack ),
1209           OFFSETOF( pTask->teb->cur_stack ), seg, ptr );
1210
1211     /* Save the old stack */
1212
1213     oldFrame = THREAD_STACK16( pTask->teb );
1214     /* pop frame + args and push bp */
1215     pData->old_ss_sp   = pTask->teb->cur_stack + sizeof(STACK16FRAME)
1216                            + 2 * sizeof(WORD);
1217     *(WORD *)PTR_SEG_TO_LIN(pData->old_ss_sp) = oldFrame->bp;
1218     pData->stacktop    = top;
1219     pData->stackmin    = ptr;
1220     pData->stackbottom = ptr;
1221
1222     /* Switch to the new stack */
1223
1224     /* Note: we need to take the 3 arguments into account; otherwise,
1225      * the stack will underflow upon return from this function.
1226      */
1227     copySize = oldFrame->bp - OFFSETOF(pData->old_ss_sp);
1228     copySize += 3 * sizeof(WORD) + sizeof(STACK16FRAME);
1229     pTask->teb->cur_stack = PTR_SEG_OFF_TO_SEGPTR( seg, ptr - copySize );
1230     newFrame = THREAD_STACK16( pTask->teb );
1231
1232     /* Copy the stack frame and the local variables to the new stack */
1233
1234     memmove( newFrame, oldFrame, copySize );
1235     newFrame->bp = ptr;
1236     *(WORD *)PTR_SEG_OFF_TO_LIN( seg, ptr ) = 0;  /* clear previous bp */
1237 }
1238
1239
1240 /***********************************************************************
1241  *           SwitchStackBack   (KERNEL.109)
1242  */
1243 void WINAPI SwitchStackBack16( CONTEXT86 *context )
1244 {
1245     STACK16FRAME *oldFrame, *newFrame;
1246     INSTANCEDATA *pData;
1247
1248     if (!(pData = (INSTANCEDATA *)GlobalLock16(SELECTOROF(NtCurrentTeb()->cur_stack))))
1249         return;
1250     if (!pData->old_ss_sp)
1251     {
1252         WARN("No previous SwitchStackTo\n" );
1253         return;
1254     }
1255     TRACE("restoring stack %04x:%04x\n",
1256           SELECTOROF(pData->old_ss_sp), OFFSETOF(pData->old_ss_sp) );
1257
1258     oldFrame = CURRENT_STACK16;
1259
1260     /* Pop bp from the previous stack */
1261
1262     BP_reg(context) = *(WORD *)PTR_SEG_TO_LIN(pData->old_ss_sp);
1263     pData->old_ss_sp += sizeof(WORD);
1264
1265     /* Switch back to the old stack */
1266
1267     NtCurrentTeb()->cur_stack = pData->old_ss_sp - sizeof(STACK16FRAME);
1268     SS_reg(context)  = SELECTOROF(pData->old_ss_sp);
1269     ESP_reg(context) = OFFSETOF(pData->old_ss_sp) - sizeof(DWORD); /*ret addr*/
1270     pData->old_ss_sp = 0;
1271
1272     /* Build a stack frame for the return */
1273
1274     newFrame = CURRENT_STACK16;
1275     newFrame->frame32     = oldFrame->frame32;
1276     newFrame->module_cs   = oldFrame->module_cs;
1277     newFrame->callfrom_ip = oldFrame->callfrom_ip;
1278     newFrame->entry_ip    = oldFrame->entry_ip;
1279 }
1280
1281
1282 /***********************************************************************
1283  *           GetTaskQueueDS16  (KERNEL.118)
1284  */
1285 void WINAPI GetTaskQueueDS16(void)
1286 {
1287     CURRENT_STACK16->ds = GlobalHandleToSel16( GetTaskQueue16(0) );
1288 }
1289
1290
1291 /***********************************************************************
1292  *           GetTaskQueueES16  (KERNEL.119)
1293  */
1294 void WINAPI GetTaskQueueES16(void)
1295 {
1296     CURRENT_STACK16->es = GlobalHandleToSel16( GetTaskQueue16(0) );
1297 }
1298
1299
1300 /***********************************************************************
1301  *           GetCurrentTask   (KERNEL.36)
1302  */
1303 HTASK16 WINAPI GetCurrentTask(void)
1304 {
1305     return PROCESS_Current()->task;
1306 }
1307
1308 DWORD WINAPI WIN16_GetCurrentTask(void)
1309 {
1310     /* This is the version used by relay code; the first task is */
1311     /* returned in the high word of the result */
1312     return MAKELONG( GetCurrentTask(), hFirstTask );
1313 }
1314
1315
1316 /***********************************************************************
1317  *           GetCurrentPDB   (KERNEL.37)
1318  *
1319  * UNDOC: returns PSP of KERNEL in high word
1320  */
1321 DWORD WINAPI GetCurrentPDB16(void)
1322 {
1323     TDB *pTask;
1324
1325     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1326     return MAKELONG(pTask->hPDB, 0); /* FIXME */
1327 }
1328
1329
1330 /***********************************************************************
1331  *           GetCurPID16   (KERNEL.157)
1332  */
1333 DWORD WINAPI GetCurPID16( DWORD unused )
1334 {
1335     return 0;
1336 }
1337
1338
1339 /***********************************************************************
1340  *           GetInstanceData   (KERNEL.54)
1341  */
1342 INT16 WINAPI GetInstanceData16( HINSTANCE16 instance, WORD buffer, INT16 len )
1343 {
1344     char *ptr = (char *)GlobalLock16( instance );
1345     if (!ptr || !len) return 0;
1346     if ((int)buffer + len >= 0x10000) len = 0x10000 - buffer;
1347     memcpy( (char *)GlobalLock16(CURRENT_DS) + buffer, ptr + buffer, len );
1348     return len;
1349 }
1350
1351
1352 /***********************************************************************
1353  *           GetExeVersion   (KERNEL.105)
1354  */
1355 WORD WINAPI GetExeVersion16(void)
1356 {
1357     TDB *pTask;
1358
1359     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1360     return pTask->version;
1361 }
1362
1363
1364 /***********************************************************************
1365  *           SetErrorMode16   (KERNEL.107)
1366  */
1367 UINT16 WINAPI SetErrorMode16( UINT16 mode )
1368 {
1369     TDB *pTask;
1370     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1371     pTask->error_mode = mode;
1372     return SetErrorMode( mode );
1373 }
1374
1375
1376 /***********************************************************************
1377  *           GetDOSEnvironment   (KERNEL.131)
1378  */
1379 SEGPTR WINAPI GetDOSEnvironment16(void)
1380 {
1381     TDB *pTask;
1382
1383     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1384     return PTR_SEG_OFF_TO_SEGPTR( pTask->pdb.environment, 0 );
1385 }
1386
1387
1388 /***********************************************************************
1389  *           GetNumTasks   (KERNEL.152)
1390  */
1391 UINT16 WINAPI GetNumTasks16(void)
1392 {
1393     return nTaskCount;
1394 }
1395
1396
1397 /***********************************************************************
1398  *           GetTaskDS   (KERNEL.155)
1399  *
1400  * Note: this function apparently returns a DWORD with LOWORD == HIWORD.
1401  * I don't think we need to bother with this.
1402  */
1403 HINSTANCE16 WINAPI GetTaskDS16(void)
1404 {
1405     TDB *pTask;
1406
1407     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1408     return pTask->hInstance;
1409 }
1410
1411 /***********************************************************************
1412  *           GetDummyModuleHandleDS   (KERNEL.602)
1413  */
1414 WORD WINAPI GetDummyModuleHandleDS16(void)
1415 {
1416     TDB *pTask;
1417     WORD selector;
1418
1419     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1420     if (!(pTask->flags & TDBF_WIN32)) return 0;
1421     selector = GlobalHandleToSel16( pTask->hModule );
1422     CURRENT_DS = selector;
1423     return selector;
1424 }
1425
1426 /***********************************************************************
1427  *           IsTask   (KERNEL.320)
1428  */
1429 BOOL16 WINAPI IsTask16( HTASK16 hTask )
1430 {
1431     TDB *pTask;
1432
1433     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return FALSE;
1434     if (GlobalSize16( hTask ) < sizeof(TDB)) return FALSE;
1435     return (pTask->magic == TDB_MAGIC);
1436 }
1437
1438
1439 /***********************************************************************
1440  *           IsWinOldApTask16   (KERNEL.158)
1441  */
1442 BOOL16 WINAPI IsWinOldApTask16( HTASK16 hTask )
1443 {
1444     /* should return bit 0 of byte 0x48 in PSP */
1445     return FALSE;
1446 }
1447
1448 /***********************************************************************
1449  *           SetTaskSignalProc   (KERNEL.38)
1450  */
1451 FARPROC16 WINAPI SetTaskSignalProc( HTASK16 hTask, FARPROC16 proc )
1452 {
1453     TDB *pTask;
1454     FARPROC16 oldProc;
1455
1456     if (!hTask) hTask = GetCurrentTask();
1457     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return NULL;
1458     oldProc = pTask->userhandler;
1459     pTask->userhandler = proc;
1460     return oldProc;
1461 }
1462
1463 /***********************************************************************
1464  *           TASK_CallTaskSignalProc
1465  */
1466 /* ### start build ### */
1467 extern WORD CALLBACK TASK_CallTo16_word_wwwww(FARPROC16,WORD,WORD,WORD,WORD,WORD);
1468 /* ### stop build ### */
1469 void TASK_CallTaskSignalProc( UINT16 uCode, HANDLE16 hTaskOrModule )
1470 {
1471     TDB *pTask = (TDB *)GlobalLock16( GetCurrentTask() );
1472     if ( !pTask || !pTask->userhandler ) return;
1473
1474     TASK_CallTo16_word_wwwww( pTask->userhandler,
1475                               hTaskOrModule, uCode, 0,
1476                               pTask->hInstance, pTask->hQueue );
1477 }
1478
1479 /***********************************************************************
1480  *           SetSigHandler   (KERNEL.140)
1481  */
1482 WORD WINAPI SetSigHandler16( FARPROC16 newhandler, FARPROC16* oldhandler,
1483                            UINT16 *oldmode, UINT16 newmode, UINT16 flag )
1484 {
1485     FIXME("(%p,%p,%p,%d,%d), unimplemented.\n",
1486           newhandler,oldhandler,oldmode,newmode,flag );
1487
1488     if (flag != 1) return 0;
1489     if (!newmode) newhandler = NULL;  /* Default handler */
1490     if (newmode != 4)
1491     {
1492         TDB *pTask;
1493
1494         if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1495         if (oldmode) *oldmode = pTask->signal_flags;
1496         pTask->signal_flags = newmode;
1497         if (oldhandler) *oldhandler = pTask->sighandler;
1498         pTask->sighandler = newhandler;
1499     }
1500     return 0;
1501 }
1502
1503
1504 /***********************************************************************
1505  *           GlobalNotify   (KERNEL.154)
1506  *
1507  * Note that GlobalNotify does _not_ return the old NotifyProc
1508  * -- contrary to LocalNotify !!
1509  */
1510 VOID WINAPI GlobalNotify16( FARPROC16 proc )
1511 {
1512     TDB *pTask;
1513
1514     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
1515     pTask->discardhandler = proc;
1516 }
1517
1518
1519 /***********************************************************************
1520  *           GetExePtr   (KERNEL.133)
1521  */
1522 static inline HMODULE16 GetExePtrHelper( HANDLE16 handle, HTASK16 *hTask )
1523 {
1524     char *ptr;
1525     HANDLE16 owner;
1526
1527       /* Check for module handle */
1528
1529     if (!(ptr = GlobalLock16( handle ))) return 0;
1530     if (((NE_MODULE *)ptr)->magic == IMAGE_OS2_SIGNATURE) return handle;
1531
1532       /* Search for this handle inside all tasks */
1533
1534     *hTask = hFirstTask;
1535     while (*hTask)
1536     {
1537         TDB *pTask = (TDB *)GlobalLock16( *hTask );
1538         if ((*hTask == handle) ||
1539             (pTask->hInstance == handle) ||
1540             (pTask->hQueue == handle) ||
1541             (pTask->hPDB == handle)) return pTask->hModule;
1542         *hTask = pTask->hNext;
1543     }
1544
1545       /* Check the owner for module handle */
1546
1547     owner = FarGetOwner16( handle );
1548     if (!(ptr = GlobalLock16( owner ))) return 0;
1549     if (((NE_MODULE *)ptr)->magic == IMAGE_OS2_SIGNATURE) return owner;
1550
1551       /* Search for the owner inside all tasks */
1552
1553     *hTask = hFirstTask;
1554     while (*hTask)
1555     {
1556         TDB *pTask = (TDB *)GlobalLock16( *hTask );
1557         if ((*hTask == owner) ||
1558             (pTask->hInstance == owner) ||
1559             (pTask->hQueue == owner) ||
1560             (pTask->hPDB == owner)) return pTask->hModule;
1561         *hTask = pTask->hNext;
1562     }
1563
1564     return 0;
1565 }
1566
1567 HMODULE16 WINAPI WIN16_GetExePtr( HANDLE16 handle )
1568 {
1569     HTASK16 hTask = 0;
1570     HMODULE16 hModule = GetExePtrHelper( handle, &hTask );
1571     STACK16FRAME *frame = CURRENT_STACK16;
1572     frame->ecx = hModule;
1573     if (hTask) frame->es = hTask;
1574     return hModule;
1575 }
1576
1577 HMODULE16 WINAPI GetExePtr( HANDLE16 handle )
1578 {
1579     HTASK16 hTask = 0;
1580     return GetExePtrHelper( handle, &hTask );
1581 }
1582
1583
1584 /***********************************************************************
1585  *           TaskFirst   (TOOLHELP.63)
1586  */
1587 BOOL16 WINAPI TaskFirst16( TASKENTRY *lpte )
1588 {
1589     lpte->hNext = hFirstTask;
1590     return TaskNext16( lpte );
1591 }
1592
1593
1594 /***********************************************************************
1595  *           TaskNext   (TOOLHELP.64)
1596  */
1597 BOOL16 WINAPI TaskNext16( TASKENTRY *lpte )
1598 {
1599     TDB *pTask;
1600     INSTANCEDATA *pInstData;
1601
1602     TRACE_(toolhelp)("(%p): task=%04x\n", lpte, lpte->hNext );
1603     if (!lpte->hNext) return FALSE;
1604     pTask = (TDB *)GlobalLock16( lpte->hNext );
1605     if (!pTask || pTask->magic != TDB_MAGIC) return FALSE;
1606     pInstData = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN( pTask->hInstance, 0 );
1607     lpte->hTask         = lpte->hNext;
1608     lpte->hTaskParent   = pTask->hParent;
1609     lpte->hInst         = pTask->hInstance;
1610     lpte->hModule       = pTask->hModule;
1611     lpte->wSS           = SELECTOROF( pTask->teb->cur_stack );
1612     lpte->wSP           = OFFSETOF( pTask->teb->cur_stack );
1613     lpte->wStackTop     = pInstData->stacktop;
1614     lpte->wStackMinimum = pInstData->stackmin;
1615     lpte->wStackBottom  = pInstData->stackbottom;
1616     lpte->wcEvents      = pTask->nEvents;
1617     lpte->hQueue        = pTask->hQueue;
1618     lstrcpynA( lpte->szModule, pTask->module_name, sizeof(lpte->szModule) );
1619     lpte->wPSPOffset    = 0x100;  /*??*/
1620     lpte->hNext         = pTask->hNext;
1621     return TRUE;
1622 }
1623
1624
1625 /***********************************************************************
1626  *           TaskFindHandle   (TOOLHELP.65)
1627  */
1628 BOOL16 WINAPI TaskFindHandle16( TASKENTRY *lpte, HTASK16 hTask )
1629 {
1630     lpte->hNext = hTask;
1631     return TaskNext16( lpte );
1632 }
1633
1634
1635 /***********************************************************************
1636  *           GetAppCompatFlags16   (KERNEL.354)
1637  */
1638 DWORD WINAPI GetAppCompatFlags16( HTASK16 hTask )
1639 {
1640     return GetAppCompatFlags( hTask );
1641 }
1642
1643
1644 /***********************************************************************
1645  *           GetAppCompatFlags32   (USER32.206)
1646  */
1647 DWORD WINAPI GetAppCompatFlags( HTASK hTask )
1648 {
1649     TDB *pTask;
1650
1651     if (!hTask) hTask = GetCurrentTask();
1652     if (!(pTask=(TDB *)GlobalLock16( (HTASK16)hTask ))) return 0;
1653     if (GlobalSize16(hTask) < sizeof(TDB)) return 0;
1654     return pTask->compat_flags;
1655 }