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 "pe_image.h"
  24 #include "process.h"
  25 #include "queue.h"
  26 #include "selectors.h"
  27 #include "stackframe.h"
  28 #include "task.h"
  29 #include "thread.h"
  30 #include "toolhelp.h"
  31 #include "winnt.h"
  32 #include "winsock.h"
  33 #include "syslevel.h"
  34 #include "debugtools.h"
  35 #include "dosexe.h"
  36 #include "services.h"
  37 #include "server.h"
  38
  39 DEFAULT_DEBUG_CHANNEL(task)
  40 DECLARE_DEBUG_CHANNEL(relay)
  41 DECLARE_DEBUG_CHANNEL(toolhelp)
  42
  43   /* Min. number of thunks allocated when creating a new segment */
  44 #define MIN_THUNKS  32
  45
  46   /* Pointer to function to switch to a larger stack */
  47 int (*IF1632_CallLargeStack)( int (*func)(), void *arg ) = NULL;
  48
  49 static THHOOK DefaultThhook = { 0 };
  50 THHOOK *pThhook = &DefaultThhook;
  51
  52 #define hCurrentTask (pThhook->CurTDB)
  53 #define hFirstTask   (pThhook->HeadTDB)
  54 #define hLockedTask  (pThhook->LockTDB)
  55
  56 static UINT16 nTaskCount = 0;
  57
  58 static HTASK initial_task;
  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     if (!initial_task) initial_task = hTask;
 389
 390     TRACE("module='%s' cmdline='%s' task=%04x\n", name, cmd_line, hTask );
 391
 392     /* Add the task to the linked list */
 393
 394     SYSLEVEL_EnterWin16Lock();
 395     TASK_LinkTask( hTask );
 396     SYSLEVEL_LeaveWin16Lock();
 397
 398     return TRUE;
 399 }
 400
 401 /***********************************************************************
 402  *           TASK_DeleteTask
 403  */
 404 static void TASK_DeleteTask( HTASK16 hTask )
 405 {
 406     TDB *pTask;
 407     HGLOBAL16 hPDB;
 408
 409     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 410     hPDB = pTask->hPDB;
 411
 412     pTask->magic = 0xdead; /* invalidate signature */
 413
 414     /* Delete the Win32 part of the task */
 415
 416 /*    PROCESS_FreePDB( pTask->teb->process ); FIXME */
 417 /*    K32OBJ_DecCount( &pTask->teb->header ); FIXME */
 418
 419     /* Free the selector aliases */
 420
 421     GLOBAL_FreeBlock( pTask->hCSAlias );
 422     GLOBAL_FreeBlock( pTask->hPDB );
 423
 424     /* Free the task module */
 425
 426     FreeModule16( pTask->hModule );
 427
 428     /* Free the task structure itself */
 429
 430     GlobalFree16( hTask );
 431
 432     /* Free all memory used by this task (including the 32-bit stack, */
 433     /* the environment block and the thunk segments). */
 434
 435     GlobalFreeAll16( hPDB );
 436 }
 437
 438 /***********************************************************************
 439  *           TASK_KillTask
 440  */
 441 void TASK_KillTask( HTASK16 hTask )
 442 {
 443     TDB *pTask;
 444
 445     /* Enter the Win16Lock to protect global data structures */
 446     SYSLEVEL_EnterWin16Lock();
 447
 448     if ( !hTask ) hTask = GetCurrentTask();
 449     pTask = (TDB *)GlobalLock16( hTask );
 450     if ( !pTask )
 451     {
 452         SYSLEVEL_LeaveWin16Lock();
 453         return;
 454     }
 455
 456     TRACE("Killing task %04x\n", hTask );
 457
 458 #ifdef MZ_SUPPORTED
 459 {
 460     /* Kill DOS VM task */
 461     NE_MODULE *pModule = NE_GetPtr( pTask->hModule );
 462     if ( pModule->lpDosTask )
 463         MZ_KillModule( pModule->lpDosTask );
 464 }
 465 #endif
 466
 467     /* Perform USER cleanup */
 468
 469     TASK_CallTaskSignalProc( USIG16_TERMINATION, hTask );
 470     PROCESS_CallUserSignalProc( USIG_PROCESS_EXIT, 0 );
 471     PROCESS_CallUserSignalProc( USIG_THREAD_EXIT, 0 );
 472     PROCESS_CallUserSignalProc( USIG_PROCESS_DESTROY, 0 );
 473
 474     if (nTaskCount <= 1)
 475     {
 476         TRACE("this is the last task, exiting\n" );
 477         ExitKernel16();
 478     }
 479
 480     /* FIXME: Hack! Send a message to the initial task so that
 481      * the GetMessage wakes up and the initial task can check whether
 482      * it is the only remaining one and terminate itself ...
 483      * The initial task should probably install hooks or something
 484      * to get informed about task termination :-/
 485      */
 486     Callout.PostAppMessage16( initial_task, WM_NULL, 0, 0 );
 487
 488     /* Remove the task from the list to be sure we never switch back to it */
 489     TASK_UnlinkTask( hTask );
 490     if( nTaskCount )
 491     {
 492         TDB* p = (TDB *)GlobalLock16( hFirstTask );
 493         while( p )
 494         {
 495             if( p->hYieldTo == hTask ) p->hYieldTo = 0;
 496             p = (TDB *)GlobalLock16( p->hNext );
 497         }
 498     }
 499
 500     pTask->nEvents = 0;
 501
 502     if ( hLockedTask == hTask )
 503         hLockedTask = 0;
 504
 505     TASK_DeleteTask( hTask );
 506
 507     /* When deleting the current task ... */
 508     if ( hTask == hCurrentTask )
 509     {
 510         DWORD lockCount;
 511
 512         /* ... schedule another one ... */
 513         TASK_Reschedule();
 514
 515         /* ... and completely release the Win16Lock, just in case. */
 516         ReleaseThunkLock( &lockCount );
 517
 518         return;
 519     }
 520
 521     SYSLEVEL_LeaveWin16Lock();
 522 }
 523
 524 /***********************************************************************
 525  *           TASK_Reschedule
 526  *
 527  * This is where all the magic of task-switching happens!
 528  *
 529  * 16-bit Windows performs non-preemptive (cooperative) multitasking.
 530  * This means that each 16-bit task runs until it voluntarily yields
 531  * control, at which point the scheduler gets active and selects the
 532  * next task to run.
 533  *
 534  * In Wine, all processes, even 16-bit ones, are scheduled preemptively
 535  * by the standard scheduler of the underlying OS.  As many 16-bit apps
 536  * *rely* on the behaviour of the Windows scheduler, however, we have
 537  * to simulate that behaviour.
 538  *
 539  * This is achieved as follows: every 16-bit task is at time (except
 540  * during task creation and deletion) in one of two states: either it
 541  * is the one currently running, then the global variable hCurrentTask
 542  * contains its task handle, or it is not currently running, then it
 543  * is blocked on a special scheduler event, a global handle to which
 544  * is stored in the task struct.
 545  *
 546  * When the current task yields control, this routine gets called. Its
 547  * purpose is to determine the next task to be active, signal the
 548  * scheduler event of that task, and then put the current task to sleep
 549  * waiting for *its* scheduler event to get signalled again.
 550  *
 551  * This routine can get called in a few other special situations as well:
 552  *
 553  * - On creation of a 16-bit task, the Unix process executing the task
 554  *   calls TASK_Reschedule once it has completed its initialization.
 555  *   At this point, the task needs to be blocked until its scheduler
 556  *   event is signalled the first time (this will be done by the parent
 557  *   process to get the task up and running).
 558  *
 559  * - When the task currently running terminates itself, this routine gets
 560  *   called and has to schedule another task, *without* blocking the
 561  *   terminating task.
 562  *
 563  * - When a 32-bit thread posts an event for a 16-bit task, it might be
 564  *   the case that *no* 16-bit task is currently running.  In this case
 565  *   the task that has now an event pending is to be scheduled.
 566  *
 567  */
 568 void TASK_Reschedule(void)
 569 {
 570     TDB *pOldTask = NULL, *pNewTask = NULL;
 571     HTASK16 hOldTask = 0, hNewTask = 0;
 572     enum { MODE_YIELD, MODE_SLEEP, MODE_WAKEUP } mode;
 573     DWORD lockCount;
 574
 575     SYSLEVEL_EnterWin16Lock();
 576
 577     /* Check what we need to do */
 578     hOldTask = GetCurrentTask();
 579     pOldTask = (TDB *)GlobalLock16( hOldTask );
 580     TRACE( "entered with hCurrentTask %04x by hTask %04x (pid %ld)\n",
 581            hCurrentTask, hOldTask, (long) getpid() );
 582
 583     if ( pOldTask && THREAD_IsWin16( NtCurrentTeb() ) )
 584     {
 585         /* We are called by an active (non-deleted) 16-bit task */
 586
 587         /* If we don't even have a current task, or else the current
 588            task has yielded, we'll need to schedule a new task and
 589            (possibly) put the calling task to sleep.  Otherwise, we
 590            only block the caller. */
 591
 592         if ( !hCurrentTask || hCurrentTask == hOldTask )
 593             mode = MODE_YIELD;
 594         else
 595             mode = MODE_SLEEP;
 596     }
 597     else
 598     {
 599         /* We are called by a deleted 16-bit task or a 32-bit thread */
 600
 601         /* The only situation where we need to do something is if we
 602            now do not have a current task.  Then, we'll need to wake up
 603            some task that has events pending. */
 604
 605         if ( !hCurrentTask || hCurrentTask == hOldTask )
 606             mode = MODE_WAKEUP;
 607         else
 608         {
 609             /* nothing to do */
 610             SYSLEVEL_LeaveWin16Lock();
 611             return;
 612         }
 613     }
 614
 615     /* Find a task to yield to: check for DirectedYield() */
 616     if ( mode == MODE_YIELD && pOldTask && pOldTask->hYieldTo )
 617     {
 618         hNewTask = pOldTask->hYieldTo;
 619         pNewTask = (TDB *)GlobalLock16( hNewTask );
 620         if( !pNewTask || !pNewTask->nEvents) hNewTask = 0;
 621         pOldTask->hYieldTo = 0;
 622     }
 623
 624     /* Find a task to yield to: check for pending events */
 625     if ( (mode == MODE_YIELD || mode == MODE_WAKEUP) && !hNewTask )
 626     {
 627         hNewTask = hFirstTask;
 628         while (hNewTask)
 629         {
 630             pNewTask = (TDB *)GlobalLock16( hNewTask );
 631
 632             TRACE( "\ttask = %04x, events = %i\n", hNewTask, pNewTask->nEvents );
 633
 634             if (pNewTask->nEvents) break;
 635             hNewTask = pNewTask->hNext;
 636         }
 637         if (hLockedTask && (hNewTask != hLockedTask)) hNewTask = 0;
 638     }
 639
 640     /* If we are still the task with highest priority, just return ... */
 641     if ( mode == MODE_YIELD && hNewTask == hCurrentTask )
 642     {
 643         TRACE("returning to the current task (%04x)\n", hCurrentTask );
 644         SYSLEVEL_LeaveWin16Lock();
 645
 646         /* Allow Win32 threads to thunk down even while a Win16 task is
 647            in a tight PeekMessage() or Yield() loop ... */
 648         ReleaseThunkLock( &lockCount );
 649         RestoreThunkLock( lockCount );
 650         return;
 651     }
 652
 653     /* If no task to yield to found, suspend 16-bit scheduler ... */
 654     if ( mode == MODE_YIELD && !hNewTask )
 655     {
 656         TRACE("No currently active task\n");
 657         hCurrentTask = 0;
 658     }
 659
 660     /* If we found a task to wake up, do it ... */
 661     if ( (mode == MODE_YIELD || mode == MODE_WAKEUP) && hNewTask )
 662     {
 663         TRACE("Switching to task %04x (%.8s)\n",
 664                       hNewTask, pNewTask->module_name );
 665
 666         pNewTask->priority++;
 667         TASK_UnlinkTask( hNewTask );
 668         TASK_LinkTask( hNewTask );
 669         pNewTask->priority--;
 670
 671         hCurrentTask = hNewTask;
 672         SetEvent( pNewTask->hEvent );
 673
 674         /* This is set just in case some app reads it ... */
 675         pNewTask->ss_sp = pNewTask->teb->cur_stack;
 676     }
 677
 678     /* If we need to put the current task to sleep, do it ... */
 679     if ( (mode == MODE_YIELD || mode == MODE_SLEEP) && hOldTask != hCurrentTask )
 680     {
 681         ResetEvent( pOldTask->hEvent );
 682
 683         ReleaseThunkLock( &lockCount );
 684         SYSLEVEL_CheckNotLevel( 1 );
 685         WaitForSingleObject( pOldTask->hEvent, INFINITE );
 686         RestoreThunkLock( lockCount );
 687     }
 688
 689     SYSLEVEL_LeaveWin16Lock();
 690 }
 691
 692 /***********************************************************************
 693  *           InitTask  (KERNEL.91)
 694  *
 695  * Called by the application startup code.
 696  */
 697 void WINAPI InitTask16( CONTEXT86 *context )
 698 {
 699     TDB *pTask;
 700     INSTANCEDATA *pinstance;
 701     SEGPTR ptr;
 702
 703     EAX_reg(context) = 0;
 704     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
 705
 706     /* Note: we need to trust that BX/CX contain the stack/heap sizes,
 707        as some apps, notably Visual Basic apps, *modify* the heap/stack
 708        size of the instance data segment before calling InitTask() */
 709
 710     /* Initialize the INSTANCEDATA structure */
 711     pinstance = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN(CURRENT_DS, 0);
 712     pinstance->stackmin    = OFFSETOF( pTask->teb->cur_stack );
 713     pinstance->stackbottom = pinstance->stackmin; /* yup, that's right. Confused me too. */
 714     pinstance->stacktop    = ( pinstance->stackmin > BX_reg(context)?
 715                                pinstance->stackmin - BX_reg(context) : 0 ) + 150;
 716
 717     /* Initialize the local heap */
 718     if ( CX_reg(context) )
 719         LocalInit16( pTask->hInstance, 0, CX_reg(context) );
 720
 721     /* Initialize implicitly loaded DLLs */
 722     NE_InitializeDLLs( pTask->hModule );
 723     NE_DllProcessAttach( pTask->hModule );
 724
 725     /* Registers on return are:
 726      * ax     1 if OK, 0 on error
 727      * cx     stack limit in bytes
 728      * dx     cmdShow parameter
 729      * si     instance handle of the previous instance
 730      * di     instance handle of the new task
 731      * es:bx  pointer to command-line inside PSP
 732      *
 733      * 0 (=%bp) is pushed on the stack
 734      */
 735     ptr = stack16_push( sizeof(WORD) );
 736     *(WORD *)PTR_SEG_TO_LIN(ptr) = 0;
 737     ESP_reg(context) -= 2;
 738
 739     EAX_reg(context) = 1;
 740
 741     if (!pTask->pdb.cmdLine[0]) EBX_reg(context) = 0x80;
 742     else
 743     {
 744         LPBYTE p = &pTask->pdb.cmdLine[1];
 745         while ((*p == ' ') || (*p == '\t')) p++;
 746         EBX_reg(context) = 0x80 + (p - pTask->pdb.cmdLine);
 747     }
 748     ECX_reg(context) = pinstance->stacktop;
 749     EDX_reg(context) = pTask->nCmdShow;
 750     ESI_reg(context) = (DWORD)pTask->hPrevInstance;
 751     EDI_reg(context) = (DWORD)pTask->hInstance;
 752     ES_reg (context) = (WORD)pTask->hPDB;
 753 }
 754
 755
 756 /***********************************************************************
 757  *           WaitEvent  (KERNEL.30)
 758  */
 759 BOOL16 WINAPI WaitEvent16( HTASK16 hTask )
 760 {
 761     TDB *pTask;
 762
 763     if (!hTask) hTask = GetCurrentTask();
 764     pTask = (TDB *)GlobalLock16( hTask );
 765
 766     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 767     {
 768         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 769         return TRUE;
 770     }
 771
 772     if (pTask->nEvents > 0)
 773     {
 774         pTask->nEvents--;
 775         return FALSE;
 776     }
 777     TASK_Reschedule();
 778
 779     /* When we get back here, we have an event */
 780
 781     if (pTask->nEvents > 0) pTask->nEvents--;
 782     return TRUE;
 783 }
 784
 785
 786 /***********************************************************************
 787  *           PostEvent  (KERNEL.31)
 788  */
 789 void WINAPI PostEvent16( HTASK16 hTask )
 790 {
 791     TDB *pTask;
 792
 793     if (!hTask) hTask = GetCurrentTask();
 794     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 795
 796     if ( !THREAD_IsWin16( pTask->teb ) )
 797     {
 798         FIXME("called for Win32 thread (%04x)!\n", pTask->teb->teb_sel );
 799         return;
 800     }
 801
 802     pTask->nEvents++;
 803
 804     /* If we are a 32-bit task, we might need to wake up the 16-bit scheduler */
 805     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 806         TASK_Reschedule();
 807 }
 808
 809
 810 /***********************************************************************
 811  *           SetPriority  (KERNEL.32)
 812  */
 813 void WINAPI SetPriority16( HTASK16 hTask, INT16 delta )
 814 {
 815     TDB *pTask;
 816     INT16 newpriority;
 817
 818     if (!hTask) hTask = GetCurrentTask();
 819     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 820     newpriority = pTask->priority + delta;
 821     if (newpriority < -32) newpriority = -32;
 822     else if (newpriority > 15) newpriority = 15;
 823
 824     pTask->priority = newpriority + 1;
 825     TASK_UnlinkTask( hTask );
 826     TASK_LinkTask( hTask );
 827     pTask->priority--;
 828 }
 829
 830
 831 /***********************************************************************
 832  *           LockCurrentTask  (KERNEL.33)
 833  */
 834 HTASK16 WINAPI LockCurrentTask16( BOOL16 bLock )
 835 {
 836     if (bLock) hLockedTask = GetCurrentTask();
 837     else hLockedTask = 0;
 838     return hLockedTask;
 839 }
 840
 841
 842 /***********************************************************************
 843  *           IsTaskLocked  (KERNEL.122)
 844  */
 845 HTASK16 WINAPI IsTaskLocked16(void)
 846 {
 847     return hLockedTask;
 848 }
 849
 850
 851 /***********************************************************************
 852  *           OldYield  (KERNEL.117)
 853  */
 854 void WINAPI OldYield16(void)
 855 {
 856     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 857
 858     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 859     {
 860         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 861         return;
 862     }
 863
 864     if (pCurTask) pCurTask->nEvents++;  /* Make sure we get back here */
 865     TASK_Reschedule();
 866     if (pCurTask) pCurTask->nEvents--;
 867 }
 868
 869 /***********************************************************************
 870  *           WIN32_OldYield16  (KERNEL.447)
 871  */
 872 void WINAPI WIN32_OldYield16(void)
 873 {
 874    DWORD count;
 875
 876    ReleaseThunkLock(&count);
 877    RestoreThunkLock(count);
 878 }
 879
 880 /***********************************************************************
 881  *           DirectedYield  (KERNEL.150)
 882  */
 883 void WINAPI DirectedYield16( HTASK16 hTask )
 884 {
 885     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 886
 887     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 888     {
 889         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 890         return;
 891     }
 892
 893     TRACE("%04x: DirectedYield(%04x)\n", pCurTask->hSelf, hTask );
 894
 895     pCurTask->hYieldTo = hTask;
 896     OldYield16();
 897
 898     TRACE("%04x: back from DirectedYield(%04x)\n", pCurTask->hSelf, hTask );
 899 }
 900
 901 /***********************************************************************
 902  *           Yield16  (KERNEL.29)
 903  */
 904 void WINAPI Yield16(void)
 905 {
 906     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 907
 908     if (pCurTask) pCurTask->hYieldTo = 0;
 909     if (pCurTask && pCurTask->hQueue) Callout.UserYield16();
 910     else OldYield16();
 911 }
 912
 913 /***********************************************************************
 914  *           KERNEL_490  (KERNEL.490)
 915  */
 916 HTASK16 WINAPI KERNEL_490( HTASK16 someTask )
 917 {
 918     if ( !someTask ) return 0;
 919
 920     FIXME("(%04x): stub\n", someTask );
 921     return 0;
 922 }
 923
 924 /***********************************************************************
 925  *           MakeProcInstance16  (KERNEL.51)
 926  */
 927 FARPROC16 WINAPI MakeProcInstance16( FARPROC16 func, HANDLE16 hInstance )
 928 {
 929     BYTE *thunk,*lfunc;
 930     SEGPTR thunkaddr;
 931
 932     TRACE("(%08lx, %04x);", (DWORD)func, hInstance);
 933
 934     if (!HIWORD(func)) {
 935       /* Win95 actually protects via SEH, but this is better for debugging */
 936       ERR("Ouch ! Called with invalid func 0x%08lx !\n", (DWORD)func);
 937       return (FARPROC16)0;
 938     }
 939
 940     if (hInstance)
 941     {
 942         if ( (!(hInstance & 4)) ||
 943              ((hInstance != 0xffff) && IS_SELECTOR_FREE(hInstance|7)) )
 944         {
 945             ERR("Invalid hInstance (%04x) passed to MakeProcInstance !\n",
 946                 hInstance);
 947             return 0;
 948         }
 949     }
 950
 951     if ( (CURRENT_DS != hInstance)
 952       && (hInstance != 0)
 953       && (hInstance != 0xffff) )
 954     {
 955         /* calling MPI with a foreign DSEG is invalid ! */
 956         ERR("Problem with hInstance? Got %04x, using %04x instead\n",
 957                    hInstance,CURRENT_DS);
 958     }
 959
 960     /* Always use the DSEG that MPI was entered with.
 961      * We used to set hInstance to GetTaskDS16(), but this should be wrong
 962      * as CURRENT_DS provides the DSEG value we need.
 963      * ("calling" DS, *not* "task" DS !) */
 964     hInstance = CURRENT_DS;
 965
 966     /* no thunking for DLLs */
 967     if (NE_GetPtr(FarGetOwner16(hInstance))->flags & NE_FFLAGS_LIBMODULE)
 968         return func;
 969
 970     thunkaddr = TASK_AllocThunk( GetCurrentTask() );
 971     if (!thunkaddr) return (FARPROC16)0;
 972     thunk = PTR_SEG_TO_LIN( thunkaddr );
 973     lfunc = PTR_SEG_TO_LIN( func );
 974
 975     TRACE("(%08lx,%04x): got thunk %08lx\n",
 976           (DWORD)func, hInstance, (DWORD)thunkaddr );
 977     if (((lfunc[0]==0x8c) && (lfunc[1]==0xd8)) || /* movw %ds, %ax */
 978         ((lfunc[0]==0x1e) && (lfunc[1]==0x58))    /* pushw %ds, popw %ax */
 979     ) {
 980         FIXME("This was the (in)famous \"thunk useless\" warning. We thought we have to overwrite with nop;nop;, but this isn't true.\n");
 981     }
 982
 983     *thunk++ = 0xb8;    /* movw instance, %ax */
 984     *thunk++ = (BYTE)(hInstance & 0xff);
 985     *thunk++ = (BYTE)(hInstance >> 8);
 986     *thunk++ = 0xea;    /* ljmp func */
 987     *(DWORD *)thunk = (DWORD)func;
 988     return (FARPROC16)thunkaddr;
 989     /* CX reg indicates if thunkaddr != NULL, implement if needed */
 990 }
 991
 992
 993 /***********************************************************************
 994  *           FreeProcInstance16  (KERNEL.52)
 995  */
 996 void WINAPI FreeProcInstance16( FARPROC16 func )
 997 {
 998     TRACE("(%08lx)\n", (DWORD)func );
 999     TASK_FreeThunk( GetCurrentTask(), (SEGPTR)func );
1000 }
1001
1002 /**********************************************************************
1003  *          TASK_GetCodeSegment
1004  *
1005  * Helper function for GetCodeHandle/GetCodeInfo: Retrieve the module
1006  * and logical segment number of a given code segment.
1007  *
1008  * 'proc' either *is* already a pair of module handle and segment number,
1009  * in which case there's nothing to do.  Otherwise, it is a pointer to
1010  * a function, and we need to retrieve the code segment.  If the pointer
1011  * happens to point to a thunk, we'll retrieve info about the code segment
1012  * where the function pointed to by the thunk resides, not the thunk itself.
1013  *
1014  * FIXME: if 'proc' is a SNOOP16 return stub, we should retrieve info about
1015  *        the function the snoop code will return to ...
1016  *
1017  */
1018 static BOOL TASK_GetCodeSegment( FARPROC16 proc, NE_MODULE **ppModule,
1019                                  SEGTABLEENTRY **ppSeg, int *pSegNr )
1020 {
1021     NE_MODULE *pModule = NULL;
1022     SEGTABLEENTRY *pSeg = NULL;
1023     int segNr;
1024
1025     /* Try pair of module handle / segment number */
1026     pModule = (NE_MODULE *) GlobalLock16( HIWORD( proc ) );
1027     if ( pModule && pModule->magic == IMAGE_OS2_SIGNATURE )
1028     {
1029         segNr = LOWORD( proc );
1030         if ( segNr && segNr <= pModule->seg_count )
1031             pSeg = NE_SEG_TABLE( pModule ) + segNr-1;
1032     }
1033
1034     /* Try thunk or function */
1035     else
1036     {
1037         BYTE *thunk = (BYTE *)PTR_SEG_TO_LIN( proc );
1038         WORD selector;
1039
1040         if ((thunk[0] == 0xb8) && (thunk[3] == 0xea))
1041             selector = thunk[6] + (thunk[7] << 8);
1042         else
1043             selector = HIWORD( proc );
1044
1045         pModule = NE_GetPtr( GlobalHandle16( selector ) );
1046         pSeg = pModule? NE_SEG_TABLE( pModule ) : NULL;
1047
1048         if ( pModule )
1049             for ( segNr = 1; segNr <= pModule->seg_count; segNr++, pSeg++ )
1050                 if ( GlobalHandleToSel16(pSeg->hSeg) == selector )
1051                     break;
1052
1053         if ( pModule && segNr > pModule->seg_count )
1054             pSeg = NULL;
1055     }
1056
1057     /* Abort if segment not found */
1058
1059     if ( !pModule || !pSeg )
1060         return FALSE;
1061
1062     /* Return segment data */
1063
1064     if ( ppModule ) *ppModule = pModule;
1065     if ( ppSeg    ) *ppSeg    = pSeg;
1066     if ( pSegNr   ) *pSegNr   = segNr;
1067
1068     return TRUE;
1069 }
1070
1071 /**********************************************************************
1072  *          GetCodeHandle    (KERNEL.93)
1073  */
1074 HANDLE16 WINAPI GetCodeHandle16( FARPROC16 proc )
1075 {
1076     SEGTABLEENTRY *pSeg;
1077
1078     if ( !TASK_GetCodeSegment( proc, NULL, &pSeg, NULL ) )
1079         return (HANDLE16)0;
1080
1081     return pSeg->hSeg;
1082 }
1083
1084 /**********************************************************************
1085  *          GetCodeInfo    (KERNEL.104)
1086  */
1087 BOOL16 WINAPI GetCodeInfo16( FARPROC16 proc, SEGINFO *segInfo )
1088 {
1089     NE_MODULE *pModule;
1090     SEGTABLEENTRY *pSeg;
1091     int segNr;
1092
1093     if ( !TASK_GetCodeSegment( proc, &pModule, &pSeg, &segNr ) )
1094         return FALSE;
1095
1096     /* Fill in segment information */
1097
1098     segInfo->offSegment = pSeg->filepos;
1099     segInfo->cbSegment  = pSeg->size;
1100     segInfo->flags      = pSeg->flags;
1101     segInfo->cbAlloc    = pSeg->minsize;
1102     segInfo->h          = pSeg->hSeg;
1103     segInfo->alignShift = pModule->alignment;
1104
1105     if ( segNr == pModule->dgroup )
1106         segInfo->cbAlloc += pModule->heap_size + pModule->stack_size;
1107
1108     /* Return module handle in %es */
1109
1110     CURRENT_STACK16->es = GlobalHandleToSel16( pModule->self );
1111
1112     return TRUE;
1113 }
1114
1115
1116 /**********************************************************************
1117  *          DefineHandleTable16    (KERNEL.94)
1118  */
1119 BOOL16 WINAPI DefineHandleTable16( WORD wOffset )
1120 {
1121     return TRUE;  /* FIXME */
1122 }
1123
1124
1125 /***********************************************************************
1126  *           SetTaskQueue  (KERNEL.34)
1127  */
1128 HQUEUE16 WINAPI SetTaskQueue16( HTASK16 hTask, HQUEUE16 hQueue )
1129 {
1130     HQUEUE16 hPrev;
1131     TDB *pTask;
1132
1133     if (!hTask) hTask = GetCurrentTask();
1134     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
1135
1136     hPrev = pTask->hQueue;
1137     pTask->hQueue = hQueue;
1138
1139     return hPrev;
1140 }
1141
1142
1143 /***********************************************************************
1144  *           GetTaskQueue  (KERNEL.35)
1145  */
1146 HQUEUE16 WINAPI GetTaskQueue16( HTASK16 hTask )
1147 {
1148     TDB *pTask;
1149
1150     if (!hTask) hTask = GetCurrentTask();
1151     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
1152     return pTask->hQueue;
1153 }
1154
1155 /***********************************************************************
1156  *           SetThreadQueue  (KERNEL.463)
1157  */
1158 HQUEUE16 WINAPI SetThreadQueue16( DWORD thread, HQUEUE16 hQueue )
1159 {
1160     TEB *teb = thread? THREAD_IdToTEB( thread ) : NtCurrentTeb();
1161     HQUEUE16 oldQueue = teb? teb->queue : 0;
1162
1163     if ( teb )
1164     {
1165         teb->queue = hQueue;
1166
1167         if ( GetTaskQueue16( teb->process->task ) == oldQueue )
1168             SetTaskQueue16( teb->process->task, hQueue );
1169     }
1170
1171     return oldQueue;
1172 }
1173
1174 /***********************************************************************
1175  *           GetThreadQueue  (KERNEL.464)
1176  */
1177 HQUEUE16 WINAPI GetThreadQueue16( DWORD thread )
1178 {
1179     TEB *teb = NULL;
1180     if ( !thread )
1181         teb = NtCurrentTeb();
1182     else if ( HIWORD(thread) )
1183         teb = THREAD_IdToTEB( thread );
1184     else if ( IsTask16( (HTASK16)thread ) )
1185         teb = ((TDB *)GlobalLock16( (HANDLE16)thread ))->teb;
1186
1187     return (HQUEUE16)(teb? teb->queue : 0);
1188 }
1189
1190 /***********************************************************************
1191  *           SetFastQueue  (KERNEL.624)
1192  */
1193 VOID WINAPI SetFastQueue16( DWORD thread, HANDLE hQueue )
1194 {
1195     TEB *teb = NULL;
1196     if ( !thread )
1197         teb = NtCurrentTeb();
1198     else if ( HIWORD(thread) )
1199         teb = THREAD_IdToTEB( thread );
1200     else if ( IsTask16( (HTASK16)thread ) )
1201         teb = ((TDB *)GlobalLock16( (HANDLE16)thread ))->teb;
1202
1203     if ( teb ) teb->queue = (HQUEUE16) hQueue;
1204 }
1205
1206 /***********************************************************************
1207  *           GetFastQueue  (KERNEL.625)
1208  */
1209 HANDLE WINAPI GetFastQueue16( void )
1210 {
1211     TEB *teb = NtCurrentTeb();
1212     if (!teb) return 0;
1213
1214     if (!teb->queue)
1215         Callout.InitThreadInput16( 0, THREAD_IsWin16(teb)? 4 : 5 );
1216
1217     if (!teb->queue)
1218         FIXME("(): should initialize thread-local queue, expect failure!\n" );
1219
1220     return (HANDLE)teb->queue;
1221 }
1222
1223 /***********************************************************************
1224  *           SwitchStackTo   (KERNEL.108)
1225  */
1226 void WINAPI SwitchStackTo16( WORD seg, WORD ptr, WORD top )
1227 {
1228     TDB *pTask;
1229     STACK16FRAME *oldFrame, *newFrame;
1230     INSTANCEDATA *pData;
1231     UINT16 copySize;
1232
1233     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
1234     if (!(pData = (INSTANCEDATA *)GlobalLock16( seg ))) return;
1235     TRACE("old=%04x:%04x new=%04x:%04x\n",
1236           SELECTOROF( pTask->teb->cur_stack ),
1237           OFFSETOF( pTask->teb->cur_stack ), seg, ptr );
1238
1239     /* Save the old stack */
1240
1241     oldFrame = THREAD_STACK16( pTask->teb );
1242     /* pop frame + args and push bp */
1243     pData->old_ss_sp   = pTask->teb->cur_stack + sizeof(STACK16FRAME)
1244                            + 2 * sizeof(WORD);
1245     *(WORD *)PTR_SEG_TO_LIN(pData->old_ss_sp) = oldFrame->bp;
1246     pData->stacktop    = top;
1247     pData->stackmin    = ptr;
1248     pData->stackbottom = ptr;
1249
1250     /* Switch to the new stack */
1251
1252     /* Note: we need to take the 3 arguments into account; otherwise,
1253      * the stack will underflow upon return from this function.
1254      */
1255     copySize = oldFrame->bp - OFFSETOF(pData->old_ss_sp);
1256     copySize += 3 * sizeof(WORD) + sizeof(STACK16FRAME);
1257     pTask->teb->cur_stack = PTR_SEG_OFF_TO_SEGPTR( seg, ptr - copySize );
1258     newFrame = THREAD_STACK16( pTask->teb );
1259
1260     /* Copy the stack frame and the local variables to the new stack */
1261
1262     memmove( newFrame, oldFrame, copySize );
1263     newFrame->bp = ptr;
1264     *(WORD *)PTR_SEG_OFF_TO_LIN( seg, ptr ) = 0;  /* clear previous bp */
1265 }
1266
1267
1268 /***********************************************************************
1269  *           SwitchStackBack   (KERNEL.109)
1270  */
1271 void WINAPI SwitchStackBack16( CONTEXT86 *context )
1272 {
1273     STACK16FRAME *oldFrame, *newFrame;
1274     INSTANCEDATA *pData;
1275
1276     if (!(pData = (INSTANCEDATA *)GlobalLock16(SELECTOROF(NtCurrentTeb()->cur_stack))))
1277         return;
1278     if (!pData->old_ss_sp)
1279     {
1280         WARN("No previous SwitchStackTo\n" );
1281         return;
1282     }
1283     TRACE("restoring stack %04x:%04x\n",
1284           SELECTOROF(pData->old_ss_sp), OFFSETOF(pData->old_ss_sp) );
1285
1286     oldFrame = CURRENT_STACK16;
1287
1288     /* Pop bp from the previous stack */
1289
1290     BP_reg(context) = *(WORD *)PTR_SEG_TO_LIN(pData->old_ss_sp);
1291     pData->old_ss_sp += sizeof(WORD);
1292
1293     /* Switch back to the old stack */
1294
1295     NtCurrentTeb()->cur_stack = pData->old_ss_sp - sizeof(STACK16FRAME);
1296     SS_reg(context)  = SELECTOROF(pData->old_ss_sp);
1297     ESP_reg(context) = OFFSETOF(pData->old_ss_sp) - sizeof(DWORD); /*ret addr*/
1298     pData->old_ss_sp = 0;
1299
1300     /* Build a stack frame for the return */
1301
1302     newFrame = CURRENT_STACK16;
1303     newFrame->frame32     = oldFrame->frame32;
1304     newFrame->module_cs   = oldFrame->module_cs;
1305     newFrame->callfrom_ip = oldFrame->callfrom_ip;
1306     newFrame->entry_ip    = oldFrame->entry_ip;
1307 }
1308
1309
1310 /***********************************************************************
1311  *           GetTaskQueueDS16  (KERNEL.118)
1312  */
1313 void WINAPI GetTaskQueueDS16(void)
1314 {
1315     CURRENT_STACK16->ds = GlobalHandleToSel16( GetTaskQueue16(0) );
1316 }
1317
1318
1319 /***********************************************************************
1320  *           GetTaskQueueES16  (KERNEL.119)
1321  */
1322 void WINAPI GetTaskQueueES16(void)
1323 {
1324     CURRENT_STACK16->es = GlobalHandleToSel16( GetTaskQueue16(0) );
1325 }
1326
1327
1328 /***********************************************************************
1329  *           GetCurrentTask   (KERNEL.36)
1330  */
1331 HTASK16 WINAPI GetCurrentTask(void)
1332 {
1333     return PROCESS_Current()->task;
1334 }
1335
1336 DWORD WINAPI WIN16_GetCurrentTask(void)
1337 {
1338     /* This is the version used by relay code; the first task is */
1339     /* returned in the high word of the result */
1340     return MAKELONG( GetCurrentTask(), hFirstTask );
1341 }
1342
1343
1344 /***********************************************************************
1345  *           GetCurrentPDB   (KERNEL.37)
1346  *
1347  * UNDOC: returns PSP of KERNEL in high word
1348  */
1349 DWORD WINAPI GetCurrentPDB16(void)
1350 {
1351     TDB *pTask;
1352
1353     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1354     return MAKELONG(pTask->hPDB, 0); /* FIXME */
1355 }
1356
1357
1358 /***********************************************************************
1359  *           GetCurPID16   (KERNEL.157)
1360  */
1361 DWORD WINAPI GetCurPID16( DWORD unused )
1362 {
1363     return 0;
1364 }
1365
1366
1367 /***********************************************************************
1368  *           GetInstanceData   (KERNEL.54)
1369  */
1370 INT16 WINAPI GetInstanceData16( HINSTANCE16 instance, WORD buffer, INT16 len )
1371 {
1372     char *ptr = (char *)GlobalLock16( instance );
1373     if (!ptr || !len) return 0;
1374     if ((int)buffer + len >= 0x10000) len = 0x10000 - buffer;
1375     memcpy( (char *)GlobalLock16(CURRENT_DS) + buffer, ptr + buffer, len );
1376     return len;
1377 }
1378
1379
1380 /***********************************************************************
1381  *           GetExeVersion   (KERNEL.105)
1382  */
1383 WORD WINAPI GetExeVersion16(void)
1384 {
1385     TDB *pTask;
1386
1387     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1388     return pTask->version;
1389 }
1390
1391
1392 /***********************************************************************
1393  *           SetErrorMode16   (KERNEL.107)
1394  */
1395 UINT16 WINAPI SetErrorMode16( UINT16 mode )
1396 {
1397     TDB *pTask;
1398     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1399     pTask->error_mode = mode;
1400     return SetErrorMode( mode );
1401 }
1402
1403
1404 /***********************************************************************
1405  *           GetDOSEnvironment   (KERNEL.131)
1406  */
1407 SEGPTR WINAPI GetDOSEnvironment16(void)
1408 {
1409     TDB *pTask;
1410
1411     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1412     return PTR_SEG_OFF_TO_SEGPTR( pTask->pdb.environment, 0 );
1413 }
1414
1415
1416 /***********************************************************************
1417  *           GetNumTasks   (KERNEL.152)
1418  */
1419 UINT16 WINAPI GetNumTasks16(void)
1420 {
1421     return nTaskCount;
1422 }
1423
1424
1425 /***********************************************************************
1426  *           GetTaskDS   (KERNEL.155)
1427  *
1428  * Note: this function apparently returns a DWORD with LOWORD == HIWORD.
1429  * I don't think we need to bother with this.
1430  */
1431 HINSTANCE16 WINAPI GetTaskDS16(void)
1432 {
1433     TDB *pTask;
1434
1435     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1436     return pTask->hInstance;
1437 }
1438
1439 /***********************************************************************
1440  *           GetDummyModuleHandleDS   (KERNEL.602)
1441  */
1442 WORD WINAPI GetDummyModuleHandleDS16(void)
1443 {
1444     TDB *pTask;
1445     WORD selector;
1446
1447     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1448     if (!(pTask->flags & TDBF_WIN32)) return 0;
1449     selector = GlobalHandleToSel16( pTask->hModule );
1450     CURRENT_DS = selector;
1451     return selector;
1452 }
1453
1454 /***********************************************************************
1455  *           IsTask   (KERNEL.320)
1456  */
1457 BOOL16 WINAPI IsTask16( HTASK16 hTask )
1458 {
1459     TDB *pTask;
1460
1461     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return FALSE;
1462     if (GlobalSize16( hTask ) < sizeof(TDB)) return FALSE;
1463     return (pTask->magic == TDB_MAGIC);
1464 }
1465
1466
1467 /***********************************************************************
1468  *           IsWinOldApTask16   (KERNEL.158)
1469  */
1470 BOOL16 WINAPI IsWinOldApTask16( HTASK16 hTask )
1471 {
1472     /* should return bit 0 of byte 0x48 in PSP */
1473     return FALSE;
1474 }
1475
1476 /***********************************************************************
1477  *           SetTaskSignalProc   (KERNEL.38)
1478  */
1479 FARPROC16 WINAPI SetTaskSignalProc( HTASK16 hTask, FARPROC16 proc )
1480 {
1481     TDB *pTask;
1482     FARPROC16 oldProc;
1483
1484     if (!hTask) hTask = GetCurrentTask();
1485     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return NULL;
1486     oldProc = pTask->userhandler;
1487     pTask->userhandler = proc;
1488     return oldProc;
1489 }
1490
1491 /***********************************************************************
1492  *           TASK_CallTaskSignalProc
1493  */
1494 /* ### start build ### */
1495 extern WORD CALLBACK TASK_CallTo16_word_wwwww(FARPROC16,WORD,WORD,WORD,WORD,WORD);
1496 /* ### stop build ### */
1497 void TASK_CallTaskSignalProc( UINT16 uCode, HANDLE16 hTaskOrModule )
1498 {
1499     TDB *pTask = (TDB *)GlobalLock16( GetCurrentTask() );
1500     if ( !pTask || !pTask->userhandler ) return;
1501
1502     TASK_CallTo16_word_wwwww( pTask->userhandler,
1503                               hTaskOrModule, uCode, 0,
1504                               pTask->hInstance, pTask->hQueue );
1505 }
1506
1507 /***********************************************************************
1508  *           SetSigHandler   (KERNEL.140)
1509  */
1510 WORD WINAPI SetSigHandler16( FARPROC16 newhandler, FARPROC16* oldhandler,
1511                            UINT16 *oldmode, UINT16 newmode, UINT16 flag )
1512 {
1513     FIXME("(%p,%p,%p,%d,%d), unimplemented.\n",
1514           newhandler,oldhandler,oldmode,newmode,flag );
1515
1516     if (flag != 1) return 0;
1517     if (!newmode) newhandler = NULL;  /* Default handler */
1518     if (newmode != 4)
1519     {
1520         TDB *pTask;
1521
1522         if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1523         if (oldmode) *oldmode = pTask->signal_flags;
1524         pTask->signal_flags = newmode;
1525         if (oldhandler) *oldhandler = pTask->sighandler;
1526         pTask->sighandler = newhandler;
1527     }
1528     return 0;
1529 }
1530
1531
1532 /***********************************************************************
1533  *           GlobalNotify   (KERNEL.154)
1534  *
1535  * Note that GlobalNotify does _not_ return the old NotifyProc
1536  * -- contrary to LocalNotify !!
1537  */
1538 VOID WINAPI GlobalNotify16( FARPROC16 proc )
1539 {
1540     TDB *pTask;
1541
1542     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
1543     pTask->discardhandler = proc;
1544 }
1545
1546
1547 /***********************************************************************
1548  *           GetExePtr   (KERNEL.133)
1549  */
1550 static inline HMODULE16 GetExePtrHelper( HANDLE16 handle, HTASK16 *hTask )
1551 {
1552     char *ptr;
1553     HANDLE16 owner;
1554
1555       /* Check for module handle */
1556
1557     if (!(ptr = GlobalLock16( handle ))) return 0;
1558     if (((NE_MODULE *)ptr)->magic == IMAGE_OS2_SIGNATURE) return handle;
1559
1560       /* Search for this handle inside all tasks */
1561
1562     *hTask = hFirstTask;
1563     while (*hTask)
1564     {
1565         TDB *pTask = (TDB *)GlobalLock16( *hTask );
1566         if ((*hTask == handle) ||
1567             (pTask->hInstance == handle) ||
1568             (pTask->hQueue == handle) ||
1569             (pTask->hPDB == handle)) return pTask->hModule;
1570         *hTask = pTask->hNext;
1571     }
1572
1573       /* Check the owner for module handle */
1574
1575     owner = FarGetOwner16( handle );
1576     if (!(ptr = GlobalLock16( owner ))) return 0;
1577     if (((NE_MODULE *)ptr)->magic == IMAGE_OS2_SIGNATURE) return owner;
1578
1579       /* Search for the owner inside all tasks */
1580
1581     *hTask = hFirstTask;
1582     while (*hTask)
1583     {
1584         TDB *pTask = (TDB *)GlobalLock16( *hTask );
1585         if ((*hTask == owner) ||
1586             (pTask->hInstance == owner) ||
1587             (pTask->hQueue == owner) ||
1588             (pTask->hPDB == owner)) return pTask->hModule;
1589         *hTask = pTask->hNext;
1590     }
1591
1592     return 0;
1593 }
1594
1595 HMODULE16 WINAPI WIN16_GetExePtr( HANDLE16 handle )
1596 {
1597     HTASK16 hTask = 0;
1598     HMODULE16 hModule = GetExePtrHelper( handle, &hTask );
1599     STACK16FRAME *frame = CURRENT_STACK16;
1600     frame->ecx = hModule;
1601     if (hTask) frame->es = hTask;
1602     return hModule;
1603 }
1604
1605 HMODULE16 WINAPI GetExePtr( HANDLE16 handle )
1606 {
1607     HTASK16 hTask = 0;
1608     return GetExePtrHelper( handle, &hTask );
1609 }
1610
1611
1612 /***********************************************************************
1613  *           TaskFirst   (TOOLHELP.63)
1614  */
1615 BOOL16 WINAPI TaskFirst16( TASKENTRY *lpte )
1616 {
1617     lpte->hNext = hFirstTask;
1618     return TaskNext16( lpte );
1619 }
1620
1621
1622 /***********************************************************************
1623  *           TaskNext   (TOOLHELP.64)
1624  */
1625 BOOL16 WINAPI TaskNext16( TASKENTRY *lpte )
1626 {
1627     TDB *pTask;
1628     INSTANCEDATA *pInstData;
1629
1630     TRACE_(toolhelp)("(%p): task=%04x\n", lpte, lpte->hNext );
1631     if (!lpte->hNext) return FALSE;
1632     pTask = (TDB *)GlobalLock16( lpte->hNext );
1633     if (!pTask || pTask->magic != TDB_MAGIC) return FALSE;
1634     pInstData = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN( pTask->hInstance, 0 );
1635     lpte->hTask         = lpte->hNext;
1636     lpte->hTaskParent   = pTask->hParent;
1637     lpte->hInst         = pTask->hInstance;
1638     lpte->hModule       = pTask->hModule;
1639     lpte->wSS           = SELECTOROF( pTask->teb->cur_stack );
1640     lpte->wSP           = OFFSETOF( pTask->teb->cur_stack );
1641     lpte->wStackTop     = pInstData->stacktop;
1642     lpte->wStackMinimum = pInstData->stackmin;
1643     lpte->wStackBottom  = pInstData->stackbottom;
1644     lpte->wcEvents      = pTask->nEvents;
1645     lpte->hQueue        = pTask->hQueue;
1646     lstrcpynA( lpte->szModule, pTask->module_name, sizeof(lpte->szModule) );
1647     lpte->wPSPOffset    = 0x100;  /*??*/
1648     lpte->hNext         = pTask->hNext;
1649     return TRUE;
1650 }
1651
1652
1653 /***********************************************************************
1654  *           TaskFindHandle   (TOOLHELP.65)
1655  */
1656 BOOL16 WINAPI TaskFindHandle16( TASKENTRY *lpte, HTASK16 hTask )
1657 {
1658     lpte->hNext = hTask;
1659     return TaskNext16( lpte );
1660 }
1661
1662
1663 /***********************************************************************
1664  *           GetAppCompatFlags16   (KERNEL.354)
1665  */
1666 DWORD WINAPI GetAppCompatFlags16( HTASK16 hTask )
1667 {
1668     return GetAppCompatFlags( hTask );
1669 }
1670
1671
1672 /***********************************************************************
1673  *           GetAppCompatFlags   (USER32.206)
1674  */
1675 DWORD WINAPI GetAppCompatFlags( HTASK hTask )
1676 {
1677     TDB *pTask;
1678
1679     if (!hTask) hTask = GetCurrentTask();
1680     if (!(pTask=(TDB *)GlobalLock16( (HTASK16)hTask ))) return 0;
1681     if (GlobalSize16(hTask) < sizeof(TDB)) return 0;
1682     return pTask->compat_flags;
1683 }