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 static HTASK initial_task;
  60
  61 /***********************************************************************
  62  *           TASK_InstallTHHook
  63  */
  64 void TASK_InstallTHHook( THHOOK *pNewThhook )
  65 {
  66      THHOOK *pOldThhook = pThhook;
  67
  68      pThhook = pNewThhook? pNewThhook : &DefaultThhook;
  69
  70      *pThhook = *pOldThhook;
  71 }
  72
  73 /***********************************************************************
  74  *           TASK_GetNextTask
  75  */
  76 HTASK16 TASK_GetNextTask( HTASK16 hTask )
  77 {
  78     TDB* pTask = (TDB*)GlobalLock16(hTask);
  79
  80     if (pTask->hNext) return pTask->hNext;
  81     return (hFirstTask != hTask) ? hFirstTask : 0;
  82 }
  83
  84 /***********************************************************************
  85  *           TASK_LinkTask
  86  */
  87 static void TASK_LinkTask( HTASK16 hTask )
  88 {
  89     HTASK16 *prevTask;
  90     TDB *pTask;
  91
  92     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
  93     prevTask = &hFirstTask;
  94     while (*prevTask)
  95     {
  96         TDB *prevTaskPtr = (TDB *)GlobalLock16( *prevTask );
  97         if (prevTaskPtr->priority >= pTask->priority) break;
  98         prevTask = &prevTaskPtr->hNext;
  99     }
 100     pTask->hNext = *prevTask;
 101     *prevTask = hTask;
 102     nTaskCount++;
 103 }
 104
 105
 106 /***********************************************************************
 107  *           TASK_UnlinkTask
 108  */
 109 static void TASK_UnlinkTask( HTASK16 hTask )
 110 {
 111     HTASK16 *prevTask;
 112     TDB *pTask;
 113
 114     prevTask = &hFirstTask;
 115     while (*prevTask && (*prevTask != hTask))
 116     {
 117         pTask = (TDB *)GlobalLock16( *prevTask );
 118         prevTask = &pTask->hNext;
 119     }
 120     if (*prevTask)
 121     {
 122         pTask = (TDB *)GlobalLock16( *prevTask );
 123         *prevTask = pTask->hNext;
 124         pTask->hNext = 0;
 125         nTaskCount--;
 126     }
 127 }
 128
 129
 130 /***********************************************************************
 131  *           TASK_CreateThunks
 132  *
 133  * Create a thunk free-list in segment 'handle', starting from offset 'offset'
 134  * and containing 'count' entries.
 135  */
 136 static void TASK_CreateThunks( HGLOBAL16 handle, WORD offset, WORD count )
 137 {
 138     int i;
 139     WORD free;
 140     THUNKS *pThunk;
 141
 142     pThunk = (THUNKS *)((BYTE *)GlobalLock16( handle ) + offset);
 143     pThunk->next = 0;
 144     pThunk->magic = THUNK_MAGIC;
 145     pThunk->free = (int)&pThunk->thunks - (int)pThunk;
 146     free = pThunk->free;
 147     for (i = 0; i < count-1; i++)
 148     {
 149         free += 8;  /* Offset of next thunk */
 150         pThunk->thunks[4*i] = free;
 151     }
 152     pThunk->thunks[4*i] = 0;  /* Last thunk */
 153 }
 154
 155
 156 /***********************************************************************
 157  *           TASK_AllocThunk
 158  *
 159  * Allocate a thunk for MakeProcInstance().
 160  */
 161 static SEGPTR TASK_AllocThunk( HTASK16 hTask )
 162 {
 163     TDB *pTask;
 164     THUNKS *pThunk;
 165     WORD sel, base;
 166
 167     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
 168     sel = pTask->hCSAlias;
 169     pThunk = &pTask->thunks;
 170     base = (int)pThunk - (int)pTask;
 171     while (!pThunk->free)
 172     {
 173         sel = pThunk->next;
 174         if (!sel)  /* Allocate a new segment */
 175         {
 176             sel = GLOBAL_Alloc( GMEM_FIXED, sizeof(THUNKS) + (MIN_THUNKS-1)*8,
 177                                 pTask->hPDB, TRUE, FALSE, FALSE );
 178             if (!sel) return (SEGPTR)0;
 179             TASK_CreateThunks( sel, 0, MIN_THUNKS );
 180             pThunk->next = sel;
 181         }
 182         pThunk = (THUNKS *)GlobalLock16( sel );
 183         base = 0;
 184     }
 185     base += pThunk->free;
 186     pThunk->free = *(WORD *)((BYTE *)pThunk + pThunk->free);
 187     return PTR_SEG_OFF_TO_SEGPTR( sel, base );
 188 }
 189
 190
 191 /***********************************************************************
 192  *           TASK_FreeThunk
 193  *
 194  * Free a MakeProcInstance() thunk.
 195  */
 196 static BOOL TASK_FreeThunk( HTASK16 hTask, SEGPTR thunk )
 197 {
 198     TDB *pTask;
 199     THUNKS *pThunk;
 200     WORD sel, base;
 201
 202     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
 203     sel = pTask->hCSAlias;
 204     pThunk = &pTask->thunks;
 205     base = (int)pThunk - (int)pTask;
 206     while (sel && (sel != HIWORD(thunk)))
 207     {
 208         sel = pThunk->next;
 209         pThunk = (THUNKS *)GlobalLock16( sel );
 210         base = 0;
 211     }
 212     if (!sel) return FALSE;
 213     *(WORD *)((BYTE *)pThunk + LOWORD(thunk) - base) = pThunk->free;
 214     pThunk->free = LOWORD(thunk) - base;
 215     return TRUE;
 216 }
 217
 218
 219 /***********************************************************************
 220  *           TASK_CallToStart
 221  *
 222  * 32-bit entry point for a new task. This function is responsible for
 223  * setting up the registers and jumping to the 16-bit entry point.
 224  */
 225 void TASK_CallToStart(void)
 226 {
 227     TDB *pTask = (TDB *)GlobalLock16( GetCurrentTask() );
 228     NE_MODULE *pModule = NE_GetPtr( pTask->hModule );
 229     SEGTABLEENTRY *pSegTable = NE_SEG_TABLE( pModule );
 230     CONTEXT86 context;
 231
 232     SYSLEVEL_EnterWin16Lock();
 233
 234     /* Add task to 16-bit scheduler pool if necessary */
 235     if ( hCurrentTask != GetCurrentTask() )
 236         TASK_Reschedule();
 237
 238     /* Registers at initialization must be:
 239      * ax   zero
 240      * bx   stack size in bytes
 241      * cx   heap size in bytes
 242      * si   previous app instance
 243      * di   current app instance
 244      * bp   zero
 245      * es   selector to the PSP
 246      * ds   dgroup of the application
 247      * ss   stack selector
 248      * sp   top of the stack
 249      */
 250
 251     memset( &context, 0, sizeof(context) );
 252     CS_reg(&context)  = GlobalHandleToSel16(pSegTable[pModule->cs - 1].hSeg);
 253     DS_reg(&context)  = GlobalHandleToSel16(pTask->hInstance);
 254     ES_reg(&context)  = pTask->hPDB;
 255     EIP_reg(&context) = pModule->ip;
 256     EBX_reg(&context) = pModule->stack_size;
 257     ECX_reg(&context) = pModule->heap_size;
 258     EDI_reg(&context) = pTask->hInstance;
 259     ESI_reg(&context) = pTask->hPrevInstance;
 260
 261     TRACE("Starting main program: cs:ip=%04lx:%04lx ds=%04lx ss:sp=%04x:%04x\n",
 262           CS_reg(&context), EIP_reg(&context), DS_reg(&context),
 263           SELECTOROF(pTask->teb->cur_stack),
 264           OFFSETOF(pTask->teb->cur_stack) );
 265
 266     Callbacks->CallRegisterShortProc( &context, 0 );
 267 }
 268
 269
 270 /***********************************************************************
 271  *           TASK_Create
 272  *
 273  * NOTE: This routine might be called by a Win32 thread. Thus, we need
 274  *       to be careful to protect global data structures. We do this
 275  *       by entering the Win16Lock while linking the task into the
 276  *       global task list.
 277  */
 278 BOOL TASK_Create( NE_MODULE *pModule, UINT16 cmdShow)
 279 {
 280     HTASK16 hTask;
 281     TDB *pTask;
 282     LPSTR cmd_line;
 283     char name[10];
 284     PDB *pdb32 = PROCESS_Current();
 285
 286       /* Allocate the task structure */
 287
 288     hTask = GLOBAL_Alloc( GMEM_FIXED | GMEM_ZEROINIT, sizeof(TDB),
 289                           pModule->self, FALSE, FALSE, FALSE );
 290     if (!hTask) return FALSE;
 291     pTask = (TDB *)GlobalLock16( hTask );
 292
 293     /* Fill the task structure */
 294
 295     pTask->nEvents       = 0;
 296     pTask->hSelf         = hTask;
 297     pTask->flags         = 0;
 298
 299     if (pModule->flags & NE_FFLAGS_WIN32)
 300         pTask->flags    |= TDBF_WIN32;
 301     if (pModule->lpDosTask)
 302         pTask->flags    |= TDBF_WINOLDAP;
 303
 304     pTask->hInstance     = pModule->self;
 305     pTask->hPrevInstance = 0;
 306     /* NOTE: for 16-bit tasks, the instance handles are updated later on
 307              in NE_InitProcess */
 308
 309     pTask->version       = pModule->expected_version;
 310     pTask->hModule       = pModule->self;
 311     pTask->hParent       = GetCurrentTask();
 312     pTask->magic         = TDB_MAGIC;
 313     pTask->nCmdShow      = cmdShow;
 314     pTask->teb           = NtCurrentTeb();
 315     pTask->curdrive      = DRIVE_GetCurrentDrive() | 0x80;
 316     strcpy( pTask->curdir, "\\" );
 317     lstrcpynA( pTask->curdir + 1, DRIVE_GetDosCwd( DRIVE_GetCurrentDrive() ),
 318                  sizeof(pTask->curdir) - 1 );
 319
 320       /* Create the thunks block */
 321
 322     TASK_CreateThunks( hTask, (int)&pTask->thunks - (int)pTask, 7 );
 323
 324       /* Copy the module name */
 325
 326     GetModuleName16( pModule->self, name, sizeof(name) );
 327     strncpy( pTask->module_name, name, sizeof(pTask->module_name) );
 328
 329       /* Allocate a selector for the PDB */
 330
 331     pTask->hPDB = GLOBAL_CreateBlock( GMEM_FIXED, &pTask->pdb, sizeof(PDB16),
 332                                     pModule->self, FALSE, FALSE, FALSE, NULL );
 333
 334       /* Fill the PDB */
 335
 336     pTask->pdb.int20 = 0x20cd;
 337     pTask->pdb.dispatcher[0] = 0x9a;  /* ljmp */
 338     PUT_DWORD(&pTask->pdb.dispatcher[1], (DWORD)NE_GetEntryPoint(
 339            GetModuleHandle16("KERNEL"), 102 ));  /* KERNEL.102 is DOS3Call() */
 340     pTask->pdb.savedint22 = INT_GetPMHandler( 0x22 );
 341     pTask->pdb.savedint23 = INT_GetPMHandler( 0x23 );
 342     pTask->pdb.savedint24 = INT_GetPMHandler( 0x24 );
 343     pTask->pdb.fileHandlesPtr =
 344         PTR_SEG_OFF_TO_SEGPTR( GlobalHandleToSel16(pTask->hPDB),
 345                                (int)&((PDB16 *)0)->fileHandles );
 346     pTask->pdb.hFileHandles = 0;
 347     memset( pTask->pdb.fileHandles, 0xff, sizeof(pTask->pdb.fileHandles) );
 348     pTask->pdb.environment    = pdb32->env_db->env_sel;
 349     pTask->pdb.nbFiles        = 20;
 350
 351     /* Fill the command line */
 352
 353     cmd_line = pdb32->env_db->cmd_line;
 354     while (*cmd_line && (*cmd_line != ' ') && (*cmd_line != '\t')) cmd_line++;
 355     while ((*cmd_line == ' ') || (*cmd_line == '\t')) cmd_line++;
 356     lstrcpynA( pTask->pdb.cmdLine+1, cmd_line, sizeof(pTask->pdb.cmdLine)-1);
 357     pTask->pdb.cmdLine[0] = strlen( pTask->pdb.cmdLine + 1 );
 358
 359       /* Get the compatibility flags */
 360
 361     pTask->compat_flags = GetProfileIntA( "Compatibility", name, 0 );
 362
 363       /* Allocate a code segment alias for the TDB */
 364
 365     pTask->hCSAlias = GLOBAL_CreateBlock( GMEM_FIXED, (void *)pTask,
 366                                           sizeof(TDB), pTask->hPDB, TRUE,
 367                                           FALSE, FALSE, NULL );
 368
 369       /* Set the owner of the environment block */
 370
 371     FarSetOwner16( pTask->pdb.environment, pTask->hPDB );
 372
 373       /* Default DTA overwrites command-line */
 374
 375     pTask->dta = PTR_SEG_OFF_TO_SEGPTR( pTask->hPDB,
 376                                 (int)&pTask->pdb.cmdLine - (int)&pTask->pdb );
 377
 378     /* Create scheduler event for 16-bit tasks */
 379
 380     if ( !(pTask->flags & TDBF_WIN32) )
 381     {
 382         pTask->hEvent = CreateEventA( NULL, TRUE, FALSE, NULL );
 383         pTask->hEvent = ConvertToGlobalHandle( pTask->hEvent );
 384     }
 385
 386     /* Enter task handle into thread and process */
 387
 388     pTask->teb->htask16 = pTask->teb->process->task = hTask;
 389     if (!initial_task) initial_task = hTask;
 390
 391     TRACE("module='%s' cmdline='%s' task=%04x\n", name, cmd_line, hTask );
 392
 393     /* Add the task to the linked list */
 394
 395     SYSLEVEL_EnterWin16Lock();
 396     TASK_LinkTask( hTask );
 397     SYSLEVEL_LeaveWin16Lock();
 398
 399     return TRUE;
 400 }
 401
 402 /***********************************************************************
 403  *           TASK_DeleteTask
 404  */
 405 static void TASK_DeleteTask( HTASK16 hTask )
 406 {
 407     TDB *pTask;
 408     HGLOBAL16 hPDB;
 409
 410     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 411     hPDB = pTask->hPDB;
 412
 413     pTask->magic = 0xdead; /* invalidate signature */
 414
 415     /* Delete the Win32 part of the task */
 416
 417 /*    PROCESS_FreePDB( pTask->teb->process ); FIXME */
 418 /*    K32OBJ_DecCount( &pTask->teb->header ); FIXME */
 419
 420     /* Free the selector aliases */
 421
 422     GLOBAL_FreeBlock( pTask->hCSAlias );
 423     GLOBAL_FreeBlock( pTask->hPDB );
 424
 425     /* Free the task module */
 426
 427     FreeModule16( pTask->hModule );
 428
 429     /* Free the task structure itself */
 430
 431     GlobalFree16( hTask );
 432
 433     /* Free all memory used by this task (including the 32-bit stack, */
 434     /* the environment block and the thunk segments). */
 435
 436     GlobalFreeAll16( hPDB );
 437 }
 438
 439 /***********************************************************************
 440  *           TASK_KillTask
 441  */
 442 void TASK_KillTask( HTASK16 hTask )
 443 {
 444     TDB *pTask;
 445
 446     /* Enter the Win16Lock to protect global data structures */
 447     SYSLEVEL_EnterWin16Lock();
 448
 449     if ( !hTask ) hTask = GetCurrentTask();
 450     pTask = (TDB *)GlobalLock16( hTask );
 451     if ( !pTask )
 452     {
 453         SYSLEVEL_LeaveWin16Lock();
 454         return;
 455     }
 456
 457     TRACE("Killing task %04x\n", hTask );
 458
 459 #ifdef MZ_SUPPORTED
 460 {
 461     /* Kill DOS VM task */
 462     NE_MODULE *pModule = NE_GetPtr( pTask->hModule );
 463     if ( pModule->lpDosTask )
 464         MZ_KillModule( pModule->lpDosTask );
 465 }
 466 #endif
 467
 468     /* Perform USER cleanup */
 469
 470     TASK_CallTaskSignalProc( USIG16_TERMINATION, hTask );
 471     PROCESS_CallUserSignalProc( USIG_PROCESS_EXIT, 0 );
 472     PROCESS_CallUserSignalProc( USIG_THREAD_EXIT, 0 );
 473     PROCESS_CallUserSignalProc( USIG_PROCESS_DESTROY, 0 );
 474
 475     if (nTaskCount <= 1)
 476     {
 477         TRACE("this is the last task, exiting\n" );
 478         ExitKernel16();
 479     }
 480
 481     /* FIXME: Hack! Send a message to the initial task so that
 482      * the GetMessage wakes up and the initial task can check whether
 483      * it is the only remaining one and terminate itself ...
 484      * The initial task should probably install hooks or something
 485      * to get informed about task termination :-/
 486      */
 487     Callout.PostAppMessage16( initial_task, WM_NULL, 0, 0 );
 488
 489     /* Remove the task from the list to be sure we never switch back to it */
 490     TASK_UnlinkTask( hTask );
 491     if( nTaskCount )
 492     {
 493         TDB* p = (TDB *)GlobalLock16( hFirstTask );
 494         while( p )
 495         {
 496             if( p->hYieldTo == hTask ) p->hYieldTo = 0;
 497             p = (TDB *)GlobalLock16( p->hNext );
 498         }
 499     }
 500
 501     pTask->nEvents = 0;
 502
 503     if ( hLockedTask == hTask )
 504         hLockedTask = 0;
 505
 506     TASK_DeleteTask( hTask );
 507
 508     /* When deleting the current task ... */
 509     if ( hTask == hCurrentTask )
 510     {
 511         DWORD lockCount;
 512
 513         /* ... schedule another one ... */
 514         TASK_Reschedule();
 515
 516         /* ... and completely release the Win16Lock, just in case. */
 517         ReleaseThunkLock( &lockCount );
 518
 519         return;
 520     }
 521
 522     SYSLEVEL_LeaveWin16Lock();
 523 }
 524
 525 /***********************************************************************
 526  *           TASK_Reschedule
 527  *
 528  * This is where all the magic of task-switching happens!
 529  *
 530  * 16-bit Windows performs non-preemptive (cooperative) multitasking.
 531  * This means that each 16-bit task runs until it voluntarily yields
 532  * control, at which point the scheduler gets active and selects the
 533  * next task to run.
 534  *
 535  * In Wine, all processes, even 16-bit ones, are scheduled preemptively
 536  * by the standard scheduler of the underlying OS.  As many 16-bit apps
 537  * *rely* on the behaviour of the Windows scheduler, however, we have
 538  * to simulate that behaviour.
 539  *
 540  * This is achieved as follows: every 16-bit task is at time (except
 541  * during task creation and deletion) in one of two states: either it
 542  * is the one currently running, then the global variable hCurrentTask
 543  * contains its task handle, or it is not currently running, then it
 544  * is blocked on a special scheduler event, a global handle to which
 545  * is stored in the task struct.
 546  *
 547  * When the current task yields control, this routine gets called. Its
 548  * purpose is to determine the next task to be active, signal the
 549  * scheduler event of that task, and then put the current task to sleep
 550  * waiting for *its* scheduler event to get signalled again.
 551  *
 552  * This routine can get called in a few other special situations as well:
 553  *
 554  * - On creation of a 16-bit task, the Unix process executing the task
 555  *   calls TASK_Reschedule once it has completed its initialization.
 556  *   At this point, the task needs to be blocked until its scheduler
 557  *   event is signalled the first time (this will be done by the parent
 558  *   process to get the task up and running).
 559  *
 560  * - When the task currently running terminates itself, this routine gets
 561  *   called and has to schedule another task, *without* blocking the
 562  *   terminating task.
 563  *
 564  * - When a 32-bit thread posts an event for a 16-bit task, it might be
 565  *   the case that *no* 16-bit task is currently running.  In this case
 566  *   the task that has now an event pending is to be scheduled.
 567  *
 568  */
 569 void TASK_Reschedule(void)
 570 {
 571     TDB *pOldTask = NULL, *pNewTask = NULL;
 572     HTASK16 hOldTask = 0, hNewTask = 0;
 573     enum { MODE_YIELD, MODE_SLEEP, MODE_WAKEUP } mode;
 574     DWORD lockCount;
 575
 576     SYSLEVEL_EnterWin16Lock();
 577
 578     /* Check what we need to do */
 579     hOldTask = GetCurrentTask();
 580     pOldTask = (TDB *)GlobalLock16( hOldTask );
 581     TRACE( "entered with hCurrentTask %04x by hTask %04x (pid %ld)\n",
 582            hCurrentTask, hOldTask, (long) getpid() );
 583
 584     if ( pOldTask && THREAD_IsWin16( NtCurrentTeb() ) )
 585     {
 586         /* We are called by an active (non-deleted) 16-bit task */
 587
 588         /* If we don't even have a current task, or else the current
 589            task has yielded, we'll need to schedule a new task and
 590            (possibly) put the calling task to sleep.  Otherwise, we
 591            only block the caller. */
 592
 593         if ( !hCurrentTask || hCurrentTask == hOldTask )
 594             mode = MODE_YIELD;
 595         else
 596             mode = MODE_SLEEP;
 597     }
 598     else
 599     {
 600         /* We are called by a deleted 16-bit task or a 32-bit thread */
 601
 602         /* The only situation where we need to do something is if we
 603            now do not have a current task.  Then, we'll need to wake up
 604            some task that has events pending. */
 605
 606         if ( !hCurrentTask || hCurrentTask == hOldTask )
 607             mode = MODE_WAKEUP;
 608         else
 609         {
 610             /* nothing to do */
 611             SYSLEVEL_LeaveWin16Lock();
 612             return;
 613         }
 614     }
 615
 616     /* Find a task to yield to: check for DirectedYield() */
 617     if ( mode == MODE_YIELD && pOldTask && pOldTask->hYieldTo )
 618     {
 619         hNewTask = pOldTask->hYieldTo;
 620         pNewTask = (TDB *)GlobalLock16( hNewTask );
 621         if( !pNewTask || !pNewTask->nEvents) hNewTask = 0;
 622         pOldTask->hYieldTo = 0;
 623     }
 624
 625     /* Find a task to yield to: check for pending events */
 626     if ( (mode == MODE_YIELD || mode == MODE_WAKEUP) && !hNewTask )
 627     {
 628         hNewTask = hFirstTask;
 629         while (hNewTask)
 630         {
 631             pNewTask = (TDB *)GlobalLock16( hNewTask );
 632
 633             TRACE( "\ttask = %04x, events = %i\n", hNewTask, pNewTask->nEvents );
 634
 635             if (pNewTask->nEvents) break;
 636             hNewTask = pNewTask->hNext;
 637         }
 638         if (hLockedTask && (hNewTask != hLockedTask)) hNewTask = 0;
 639     }
 640
 641     /* If we are still the task with highest priority, just return ... */
 642     if ( mode == MODE_YIELD && hNewTask == hCurrentTask )
 643     {
 644         TRACE("returning to the current task (%04x)\n", hCurrentTask );
 645         SYSLEVEL_LeaveWin16Lock();
 646
 647         /* Allow Win32 threads to thunk down even while a Win16 task is
 648            in a tight PeekMessage() or Yield() loop ... */
 649         ReleaseThunkLock( &lockCount );
 650         RestoreThunkLock( lockCount );
 651         return;
 652     }
 653
 654     /* If no task to yield to found, suspend 16-bit scheduler ... */
 655     if ( mode == MODE_YIELD && !hNewTask )
 656     {
 657         TRACE("No currently active task\n");
 658         hCurrentTask = 0;
 659     }
 660
 661     /* If we found a task to wake up, do it ... */
 662     if ( (mode == MODE_YIELD || mode == MODE_WAKEUP) && hNewTask )
 663     {
 664         TRACE("Switching to task %04x (%.8s)\n",
 665                       hNewTask, pNewTask->module_name );
 666
 667         pNewTask->priority++;
 668         TASK_UnlinkTask( hNewTask );
 669         TASK_LinkTask( hNewTask );
 670         pNewTask->priority--;
 671
 672         hCurrentTask = hNewTask;
 673         SetEvent( pNewTask->hEvent );
 674
 675         /* This is set just in case some app reads it ... */
 676         pNewTask->ss_sp = pNewTask->teb->cur_stack;
 677     }
 678
 679     /* If we need to put the current task to sleep, do it ... */
 680     if ( (mode == MODE_YIELD || mode == MODE_SLEEP) && hOldTask != hCurrentTask )
 681     {
 682         ResetEvent( pOldTask->hEvent );
 683
 684         ReleaseThunkLock( &lockCount );
 685         SYSLEVEL_CheckNotLevel( 1 );
 686         WaitForSingleObject( pOldTask->hEvent, INFINITE );
 687         RestoreThunkLock( lockCount );
 688     }
 689
 690     SYSLEVEL_LeaveWin16Lock();
 691 }
 692
 693 /***********************************************************************
 694  *           InitTask  (KERNEL.91)
 695  *
 696  * Called by the application startup code.
 697  */
 698 void WINAPI InitTask16( CONTEXT86 *context )
 699 {
 700     TDB *pTask;
 701     INSTANCEDATA *pinstance;
 702     SEGPTR ptr;
 703
 704     EAX_reg(context) = 0;
 705     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
 706
 707     /* Note: we need to trust that BX/CX contain the stack/heap sizes,
 708        as some apps, notably Visual Basic apps, *modify* the heap/stack
 709        size of the instance data segment before calling InitTask() */
 710
 711     /* Initialize the INSTANCEDATA structure */
 712     pinstance = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN(CURRENT_DS, 0);
 713     pinstance->stackmin    = OFFSETOF( pTask->teb->cur_stack );
 714     pinstance->stackbottom = pinstance->stackmin; /* yup, that's right. Confused me too. */
 715     pinstance->stacktop    = ( pinstance->stackmin > BX_reg(context)?
 716                                pinstance->stackmin - BX_reg(context) : 0 ) + 150;
 717
 718     /* Initialize the local heap */
 719     if ( CX_reg(context) )
 720         LocalInit16( pTask->hInstance, 0, CX_reg(context) );
 721
 722     /* Initialize implicitly loaded DLLs */
 723     NE_InitializeDLLs( pTask->hModule );
 724     NE_DllProcessAttach( pTask->hModule );
 725
 726     /* Registers on return are:
 727      * ax     1 if OK, 0 on error
 728      * cx     stack limit in bytes
 729      * dx     cmdShow parameter
 730      * si     instance handle of the previous instance
 731      * di     instance handle of the new task
 732      * es:bx  pointer to command-line inside PSP
 733      *
 734      * 0 (=%bp) is pushed on the stack
 735      */
 736     ptr = stack16_push( sizeof(WORD) );
 737     *(WORD *)PTR_SEG_TO_LIN(ptr) = 0;
 738     ESP_reg(context) -= 2;
 739
 740     EAX_reg(context) = 1;
 741
 742     if (!pTask->pdb.cmdLine[0]) EBX_reg(context) = 0x80;
 743     else
 744     {
 745         LPBYTE p = &pTask->pdb.cmdLine[1];
 746         while ((*p == ' ') || (*p == '\t')) p++;
 747         EBX_reg(context) = 0x80 + (p - pTask->pdb.cmdLine);
 748     }
 749     ECX_reg(context) = pinstance->stacktop;
 750     EDX_reg(context) = pTask->nCmdShow;
 751     ESI_reg(context) = (DWORD)pTask->hPrevInstance;
 752     EDI_reg(context) = (DWORD)pTask->hInstance;
 753     ES_reg (context) = (WORD)pTask->hPDB;
 754 }
 755
 756
 757 /***********************************************************************
 758  *           WaitEvent  (KERNEL.30)
 759  */
 760 BOOL16 WINAPI WaitEvent16( HTASK16 hTask )
 761 {
 762     TDB *pTask;
 763
 764     if (!hTask) hTask = GetCurrentTask();
 765     pTask = (TDB *)GlobalLock16( hTask );
 766
 767     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 768     {
 769         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 770         return TRUE;
 771     }
 772
 773     if (pTask->nEvents > 0)
 774     {
 775         pTask->nEvents--;
 776         return FALSE;
 777     }
 778     TASK_Reschedule();
 779
 780     /* When we get back here, we have an event */
 781
 782     if (pTask->nEvents > 0) pTask->nEvents--;
 783     return TRUE;
 784 }
 785
 786
 787 /***********************************************************************
 788  *           PostEvent  (KERNEL.31)
 789  */
 790 void WINAPI PostEvent16( HTASK16 hTask )
 791 {
 792     TDB *pTask;
 793
 794     if (!hTask) hTask = GetCurrentTask();
 795     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 796
 797     if ( !THREAD_IsWin16( pTask->teb ) )
 798     {
 799         FIXME("called for Win32 thread (%04x)!\n", pTask->teb->teb_sel );
 800         return;
 801     }
 802
 803     pTask->nEvents++;
 804
 805     /* If we are a 32-bit task, we might need to wake up the 16-bit scheduler */
 806     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 807         TASK_Reschedule();
 808 }
 809
 810
 811 /***********************************************************************
 812  *           SetPriority  (KERNEL.32)
 813  */
 814 void WINAPI SetPriority16( HTASK16 hTask, INT16 delta )
 815 {
 816     TDB *pTask;
 817     INT16 newpriority;
 818
 819     if (!hTask) hTask = GetCurrentTask();
 820     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return;
 821     newpriority = pTask->priority + delta;
 822     if (newpriority < -32) newpriority = -32;
 823     else if (newpriority > 15) newpriority = 15;
 824
 825     pTask->priority = newpriority + 1;
 826     TASK_UnlinkTask( hTask );
 827     TASK_LinkTask( hTask );
 828     pTask->priority--;
 829 }
 830
 831
 832 /***********************************************************************
 833  *           LockCurrentTask  (KERNEL.33)
 834  */
 835 HTASK16 WINAPI LockCurrentTask16( BOOL16 bLock )
 836 {
 837     if (bLock) hLockedTask = GetCurrentTask();
 838     else hLockedTask = 0;
 839     return hLockedTask;
 840 }
 841
 842
 843 /***********************************************************************
 844  *           IsTaskLocked  (KERNEL.122)
 845  */
 846 HTASK16 WINAPI IsTaskLocked16(void)
 847 {
 848     return hLockedTask;
 849 }
 850
 851
 852 /***********************************************************************
 853  *           OldYield  (KERNEL.117)
 854  */
 855 void WINAPI OldYield16(void)
 856 {
 857     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 858
 859     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 860     {
 861         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 862         return;
 863     }
 864
 865     if (pCurTask) pCurTask->nEvents++;  /* Make sure we get back here */
 866     TASK_Reschedule();
 867     if (pCurTask) pCurTask->nEvents--;
 868 }
 869
 870 /***********************************************************************
 871  *           WIN32_OldYield16  (KERNEL.447)
 872  */
 873 void WINAPI WIN32_OldYield16(void)
 874 {
 875    DWORD count;
 876
 877    ReleaseThunkLock(&count);
 878    RestoreThunkLock(count);
 879 }
 880
 881 /***********************************************************************
 882  *           DirectedYield  (KERNEL.150)
 883  */
 884 void WINAPI DirectedYield16( HTASK16 hTask )
 885 {
 886     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 887
 888     if ( !THREAD_IsWin16( NtCurrentTeb() ) )
 889     {
 890         FIXME("called for Win32 thread (%04x)!\n", NtCurrentTeb()->teb_sel);
 891         return;
 892     }
 893
 894     TRACE("%04x: DirectedYield(%04x)\n", pCurTask->hSelf, hTask );
 895
 896     pCurTask->hYieldTo = hTask;
 897     OldYield16();
 898
 899     TRACE("%04x: back from DirectedYield(%04x)\n", pCurTask->hSelf, hTask );
 900 }
 901
 902 /***********************************************************************
 903  *           Yield16  (KERNEL.29)
 904  */
 905 void WINAPI Yield16(void)
 906 {
 907     TDB *pCurTask = (TDB *)GlobalLock16( GetCurrentTask() );
 908
 909     if (pCurTask) pCurTask->hYieldTo = 0;
 910     if (pCurTask && pCurTask->hQueue) Callout.UserYield16();
 911     else OldYield16();
 912 }
 913
 914 /***********************************************************************
 915  *           KERNEL_490  (KERNEL.490)
 916  */
 917 HTASK16 WINAPI KERNEL_490( HTASK16 someTask )
 918 {
 919     if ( !someTask ) return 0;
 920
 921     FIXME("(%04x): stub\n", someTask );
 922     return 0;
 923 }
 924
 925 /***********************************************************************
 926  *           MakeProcInstance16  (KERNEL.51)
 927  */
 928 FARPROC16 WINAPI MakeProcInstance16( FARPROC16 func, HANDLE16 hInstance )
 929 {
 930     BYTE *thunk,*lfunc;
 931     SEGPTR thunkaddr;
 932
 933     TRACE("(%08lx, %04x);", (DWORD)func, hInstance);
 934
 935     if (!HIWORD(func)) {
 936       /* Win95 actually protects via SEH, but this is better for debugging */
 937       ERR("Ouch ! Called with invalid func 0x%08lx !\n", (DWORD)func);
 938       return (FARPROC16)0;
 939     }
 940
 941     if (hInstance)
 942     {
 943         if ( (!(hInstance & 4)) ||
 944              ((hInstance != 0xffff) && IS_SELECTOR_FREE(hInstance|7)) )
 945         {
 946             ERR("Invalid hInstance (%04x) passed to MakeProcInstance !\n",
 947                 hInstance);
 948             return 0;
 949         }
 950     }
 951
 952     if ( (CURRENT_DS != hInstance)
 953       && (hInstance != 0)
 954       && (hInstance != 0xffff) )
 955     {
 956         /* calling MPI with a foreign DSEG is invalid ! */
 957         ERR("Problem with hInstance? Got %04x, using %04x instead\n",
 958                    hInstance,CURRENT_DS);
 959     }
 960
 961     /* Always use the DSEG that MPI was entered with.
 962      * We used to set hInstance to GetTaskDS16(), but this should be wrong
 963      * as CURRENT_DS provides the DSEG value we need.
 964      * ("calling" DS, *not* "task" DS !) */
 965     hInstance = CURRENT_DS;
 966
 967     /* no thunking for DLLs */
 968     if (NE_GetPtr(FarGetOwner16(hInstance))->flags & NE_FFLAGS_LIBMODULE)
 969         return func;
 970
 971     thunkaddr = TASK_AllocThunk( GetCurrentTask() );
 972     if (!thunkaddr) return (FARPROC16)0;
 973     thunk = PTR_SEG_TO_LIN( thunkaddr );
 974     lfunc = PTR_SEG_TO_LIN( func );
 975
 976     TRACE("(%08lx,%04x): got thunk %08lx\n",
 977           (DWORD)func, hInstance, (DWORD)thunkaddr );
 978     if (((lfunc[0]==0x8c) && (lfunc[1]==0xd8)) || /* movw %ds, %ax */
 979         ((lfunc[0]==0x1e) && (lfunc[1]==0x58))    /* pushw %ds, popw %ax */
 980     ) {
 981         FIXME("This was the (in)famous \"thunk useless\" warning. We thought we have to overwrite with nop;nop;, but this isn't true.\n");
 982     }
 983
 984     *thunk++ = 0xb8;    /* movw instance, %ax */
 985     *thunk++ = (BYTE)(hInstance & 0xff);
 986     *thunk++ = (BYTE)(hInstance >> 8);
 987     *thunk++ = 0xea;    /* ljmp func */
 988     *(DWORD *)thunk = (DWORD)func;
 989     return (FARPROC16)thunkaddr;
 990     /* CX reg indicates if thunkaddr != NULL, implement if needed */
 991 }
 992
 993
 994 /***********************************************************************
 995  *           FreeProcInstance16  (KERNEL.52)
 996  */
 997 void WINAPI FreeProcInstance16( FARPROC16 func )
 998 {
 999     TRACE("(%08lx)\n", (DWORD)func );
1000     TASK_FreeThunk( GetCurrentTask(), (SEGPTR)func );
1001 }
1002
1003 /**********************************************************************
1004  *          TASK_GetCodeSegment
1005  *
1006  * Helper function for GetCodeHandle/GetCodeInfo: Retrieve the module
1007  * and logical segment number of a given code segment.
1008  *
1009  * 'proc' either *is* already a pair of module handle and segment number,
1010  * in which case there's nothing to do.  Otherwise, it is a pointer to
1011  * a function, and we need to retrieve the code segment.  If the pointer
1012  * happens to point to a thunk, we'll retrieve info about the code segment
1013  * where the function pointed to by the thunk resides, not the thunk itself.
1014  *
1015  * FIXME: if 'proc' is a SNOOP16 return stub, we should retrieve info about
1016  *        the function the snoop code will return to ...
1017  *
1018  */
1019 static BOOL TASK_GetCodeSegment( FARPROC16 proc, NE_MODULE **ppModule,
1020                                  SEGTABLEENTRY **ppSeg, int *pSegNr )
1021 {
1022     NE_MODULE *pModule = NULL;
1023     SEGTABLEENTRY *pSeg = NULL;
1024     int segNr;
1025
1026     /* Try pair of module handle / segment number */
1027     pModule = (NE_MODULE *) GlobalLock16( HIWORD( proc ) );
1028     if ( pModule && pModule->magic == IMAGE_OS2_SIGNATURE )
1029     {
1030         segNr = LOWORD( proc );
1031         if ( segNr && segNr <= pModule->seg_count )
1032             pSeg = NE_SEG_TABLE( pModule ) + segNr-1;
1033     }
1034
1035     /* Try thunk or function */
1036     else
1037     {
1038         BYTE *thunk = (BYTE *)PTR_SEG_TO_LIN( proc );
1039         WORD selector;
1040
1041         if ((thunk[0] == 0xb8) && (thunk[3] == 0xea))
1042             selector = thunk[6] + (thunk[7] << 8);
1043         else
1044             selector = HIWORD( proc );
1045
1046         pModule = NE_GetPtr( GlobalHandle16( selector ) );
1047         pSeg = pModule? NE_SEG_TABLE( pModule ) : NULL;
1048
1049         if ( pModule )
1050             for ( segNr = 1; segNr <= pModule->seg_count; segNr++, pSeg++ )
1051                 if ( GlobalHandleToSel16(pSeg->hSeg) == selector )
1052                     break;
1053
1054         if ( pModule && segNr > pModule->seg_count )
1055             pSeg = NULL;
1056     }
1057
1058     /* Abort if segment not found */
1059
1060     if ( !pModule || !pSeg )
1061         return FALSE;
1062
1063     /* Return segment data */
1064
1065     if ( ppModule ) *ppModule = pModule;
1066     if ( ppSeg    ) *ppSeg    = pSeg;
1067     if ( pSegNr   ) *pSegNr   = segNr;
1068
1069     return TRUE;
1070 }
1071
1072 /**********************************************************************
1073  *          GetCodeHandle    (KERNEL.93)
1074  */
1075 HANDLE16 WINAPI GetCodeHandle16( FARPROC16 proc )
1076 {
1077     SEGTABLEENTRY *pSeg;
1078
1079     if ( !TASK_GetCodeSegment( proc, NULL, &pSeg, NULL ) )
1080         return (HANDLE16)0;
1081
1082     return pSeg->hSeg;
1083 }
1084
1085 /**********************************************************************
1086  *          GetCodeInfo    (KERNEL.104)
1087  */
1088 BOOL16 WINAPI GetCodeInfo16( FARPROC16 proc, SEGINFO *segInfo )
1089 {
1090     NE_MODULE *pModule;
1091     SEGTABLEENTRY *pSeg;
1092     int segNr;
1093
1094     if ( !TASK_GetCodeSegment( proc, &pModule, &pSeg, &segNr ) )
1095         return FALSE;
1096
1097     /* Fill in segment information */
1098
1099     segInfo->offSegment = pSeg->filepos;
1100     segInfo->cbSegment  = pSeg->size;
1101     segInfo->flags      = pSeg->flags;
1102     segInfo->cbAlloc    = pSeg->minsize;
1103     segInfo->h          = pSeg->hSeg;
1104     segInfo->alignShift = pModule->alignment;
1105
1106     if ( segNr == pModule->dgroup )
1107         segInfo->cbAlloc += pModule->heap_size + pModule->stack_size;
1108
1109     /* Return module handle in %es */
1110
1111     CURRENT_STACK16->es = GlobalHandleToSel16( pModule->self );
1112
1113     return TRUE;
1114 }
1115
1116
1117 /**********************************************************************
1118  *          DefineHandleTable16    (KERNEL.94)
1119  */
1120 BOOL16 WINAPI DefineHandleTable16( WORD wOffset )
1121 {
1122     return TRUE;  /* FIXME */
1123 }
1124
1125
1126 /***********************************************************************
1127  *           SetTaskQueue  (KERNEL.34)
1128  */
1129 HQUEUE16 WINAPI SetTaskQueue16( HTASK16 hTask, HQUEUE16 hQueue )
1130 {
1131     HQUEUE16 hPrev;
1132     TDB *pTask;
1133
1134     if (!hTask) hTask = GetCurrentTask();
1135     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
1136
1137     hPrev = pTask->hQueue;
1138     pTask->hQueue = hQueue;
1139
1140     return hPrev;
1141 }
1142
1143
1144 /***********************************************************************
1145  *           GetTaskQueue  (KERNEL.35)
1146  */
1147 HQUEUE16 WINAPI GetTaskQueue16( HTASK16 hTask )
1148 {
1149     TDB *pTask;
1150
1151     if (!hTask) hTask = GetCurrentTask();
1152     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return 0;
1153     return pTask->hQueue;
1154 }
1155
1156 /***********************************************************************
1157  *           SetThreadQueue  (KERNEL.463)
1158  */
1159 HQUEUE16 WINAPI SetThreadQueue16( DWORD thread, HQUEUE16 hQueue )
1160 {
1161     TEB *teb = thread? THREAD_IdToTEB( thread ) : NtCurrentTeb();
1162     HQUEUE16 oldQueue = teb? teb->queue : 0;
1163
1164     if ( teb )
1165     {
1166         teb->queue = hQueue;
1167
1168         if ( GetTaskQueue16( teb->process->task ) == oldQueue )
1169             SetTaskQueue16( teb->process->task, hQueue );
1170     }
1171
1172     return oldQueue;
1173 }
1174
1175 /***********************************************************************
1176  *           GetThreadQueue  (KERNEL.464)
1177  */
1178 HQUEUE16 WINAPI GetThreadQueue16( DWORD thread )
1179 {
1180     TEB *teb = NULL;
1181     if ( !thread )
1182         teb = NtCurrentTeb();
1183     else if ( HIWORD(thread) )
1184         teb = THREAD_IdToTEB( thread );
1185     else if ( IsTask16( (HTASK16)thread ) )
1186         teb = ((TDB *)GlobalLock16( (HANDLE16)thread ))->teb;
1187
1188     return (HQUEUE16)(teb? teb->queue : 0);
1189 }
1190
1191 /***********************************************************************
1192  *           SetFastQueue  (KERNEL.624)
1193  */
1194 VOID WINAPI SetFastQueue16( DWORD thread, HANDLE hQueue )
1195 {
1196     TEB *teb = NULL;
1197     if ( !thread )
1198         teb = NtCurrentTeb();
1199     else if ( HIWORD(thread) )
1200         teb = THREAD_IdToTEB( thread );
1201     else if ( IsTask16( (HTASK16)thread ) )
1202         teb = ((TDB *)GlobalLock16( (HANDLE16)thread ))->teb;
1203
1204     if ( teb ) teb->queue = (HQUEUE16) hQueue;
1205 }
1206
1207 /***********************************************************************
1208  *           GetFastQueue  (KERNEL.625)
1209  */
1210 HANDLE WINAPI GetFastQueue16( void )
1211 {
1212     TEB *teb = NtCurrentTeb();
1213     if (!teb) return 0;
1214
1215     if (!teb->queue)
1216         Callout.InitThreadInput16( 0, THREAD_IsWin16(teb)? 4 : 5 );
1217
1218     if (!teb->queue)
1219         FIXME("(): should initialize thread-local queue, expect failure!\n" );
1220
1221     return (HANDLE)teb->queue;
1222 }
1223
1224 /***********************************************************************
1225  *           SwitchStackTo   (KERNEL.108)
1226  */
1227 void WINAPI SwitchStackTo16( WORD seg, WORD ptr, WORD top )
1228 {
1229     TDB *pTask;
1230     STACK16FRAME *oldFrame, *newFrame;
1231     INSTANCEDATA *pData;
1232     UINT16 copySize;
1233
1234     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
1235     if (!(pData = (INSTANCEDATA *)GlobalLock16( seg ))) return;
1236     TRACE("old=%04x:%04x new=%04x:%04x\n",
1237           SELECTOROF( pTask->teb->cur_stack ),
1238           OFFSETOF( pTask->teb->cur_stack ), seg, ptr );
1239
1240     /* Save the old stack */
1241
1242     oldFrame = THREAD_STACK16( pTask->teb );
1243     /* pop frame + args and push bp */
1244     pData->old_ss_sp   = pTask->teb->cur_stack + sizeof(STACK16FRAME)
1245                            + 2 * sizeof(WORD);
1246     *(WORD *)PTR_SEG_TO_LIN(pData->old_ss_sp) = oldFrame->bp;
1247     pData->stacktop    = top;
1248     pData->stackmin    = ptr;
1249     pData->stackbottom = ptr;
1250
1251     /* Switch to the new stack */
1252
1253     /* Note: we need to take the 3 arguments into account; otherwise,
1254      * the stack will underflow upon return from this function.
1255      */
1256     copySize = oldFrame->bp - OFFSETOF(pData->old_ss_sp);
1257     copySize += 3 * sizeof(WORD) + sizeof(STACK16FRAME);
1258     pTask->teb->cur_stack = PTR_SEG_OFF_TO_SEGPTR( seg, ptr - copySize );
1259     newFrame = THREAD_STACK16( pTask->teb );
1260
1261     /* Copy the stack frame and the local variables to the new stack */
1262
1263     memmove( newFrame, oldFrame, copySize );
1264     newFrame->bp = ptr;
1265     *(WORD *)PTR_SEG_OFF_TO_LIN( seg, ptr ) = 0;  /* clear previous bp */
1266 }
1267
1268
1269 /***********************************************************************
1270  *           SwitchStackBack   (KERNEL.109)
1271  */
1272 void WINAPI SwitchStackBack16( CONTEXT86 *context )
1273 {
1274     STACK16FRAME *oldFrame, *newFrame;
1275     INSTANCEDATA *pData;
1276
1277     if (!(pData = (INSTANCEDATA *)GlobalLock16(SELECTOROF(NtCurrentTeb()->cur_stack))))
1278         return;
1279     if (!pData->old_ss_sp)
1280     {
1281         WARN("No previous SwitchStackTo\n" );
1282         return;
1283     }
1284     TRACE("restoring stack %04x:%04x\n",
1285           SELECTOROF(pData->old_ss_sp), OFFSETOF(pData->old_ss_sp) );
1286
1287     oldFrame = CURRENT_STACK16;
1288
1289     /* Pop bp from the previous stack */
1290
1291     BP_reg(context) = *(WORD *)PTR_SEG_TO_LIN(pData->old_ss_sp);
1292     pData->old_ss_sp += sizeof(WORD);
1293
1294     /* Switch back to the old stack */
1295
1296     NtCurrentTeb()->cur_stack = pData->old_ss_sp - sizeof(STACK16FRAME);
1297     SS_reg(context)  = SELECTOROF(pData->old_ss_sp);
1298     ESP_reg(context) = OFFSETOF(pData->old_ss_sp) - sizeof(DWORD); /*ret addr*/
1299     pData->old_ss_sp = 0;
1300
1301     /* Build a stack frame for the return */
1302
1303     newFrame = CURRENT_STACK16;
1304     newFrame->frame32     = oldFrame->frame32;
1305     newFrame->module_cs   = oldFrame->module_cs;
1306     newFrame->callfrom_ip = oldFrame->callfrom_ip;
1307     newFrame->entry_ip    = oldFrame->entry_ip;
1308 }
1309
1310
1311 /***********************************************************************
1312  *           GetTaskQueueDS16  (KERNEL.118)
1313  */
1314 void WINAPI GetTaskQueueDS16(void)
1315 {
1316     CURRENT_STACK16->ds = GlobalHandleToSel16( GetTaskQueue16(0) );
1317 }
1318
1319
1320 /***********************************************************************
1321  *           GetTaskQueueES16  (KERNEL.119)
1322  */
1323 void WINAPI GetTaskQueueES16(void)
1324 {
1325     CURRENT_STACK16->es = GlobalHandleToSel16( GetTaskQueue16(0) );
1326 }
1327
1328
1329 /***********************************************************************
1330  *           GetCurrentTask   (KERNEL.36)
1331  */
1332 HTASK16 WINAPI GetCurrentTask(void)
1333 {
1334     return PROCESS_Current()->task;
1335 }
1336
1337 DWORD WINAPI WIN16_GetCurrentTask(void)
1338 {
1339     /* This is the version used by relay code; the first task is */
1340     /* returned in the high word of the result */
1341     return MAKELONG( GetCurrentTask(), hFirstTask );
1342 }
1343
1344
1345 /***********************************************************************
1346  *           GetCurrentPDB   (KERNEL.37)
1347  *
1348  * UNDOC: returns PSP of KERNEL in high word
1349  */
1350 DWORD WINAPI GetCurrentPDB16(void)
1351 {
1352     TDB *pTask;
1353
1354     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1355     return MAKELONG(pTask->hPDB, 0); /* FIXME */
1356 }
1357
1358
1359 /***********************************************************************
1360  *           GetCurPID16   (KERNEL.157)
1361  */
1362 DWORD WINAPI GetCurPID16( DWORD unused )
1363 {
1364     return 0;
1365 }
1366
1367
1368 /***********************************************************************
1369  *           GetInstanceData   (KERNEL.54)
1370  */
1371 INT16 WINAPI GetInstanceData16( HINSTANCE16 instance, WORD buffer, INT16 len )
1372 {
1373     char *ptr = (char *)GlobalLock16( instance );
1374     if (!ptr || !len) return 0;
1375     if ((int)buffer + len >= 0x10000) len = 0x10000 - buffer;
1376     memcpy( (char *)GlobalLock16(CURRENT_DS) + buffer, ptr + buffer, len );
1377     return len;
1378 }
1379
1380
1381 /***********************************************************************
1382  *           GetExeVersion   (KERNEL.105)
1383  */
1384 WORD WINAPI GetExeVersion16(void)
1385 {
1386     TDB *pTask;
1387
1388     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1389     return pTask->version;
1390 }
1391
1392
1393 /***********************************************************************
1394  *           SetErrorMode16   (KERNEL.107)
1395  */
1396 UINT16 WINAPI SetErrorMode16( UINT16 mode )
1397 {
1398     TDB *pTask;
1399     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1400     pTask->error_mode = mode;
1401     return SetErrorMode( mode );
1402 }
1403
1404
1405 /***********************************************************************
1406  *           GetDOSEnvironment   (KERNEL.131)
1407  */
1408 SEGPTR WINAPI GetDOSEnvironment16(void)
1409 {
1410     TDB *pTask;
1411
1412     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1413     return PTR_SEG_OFF_TO_SEGPTR( pTask->pdb.environment, 0 );
1414 }
1415
1416
1417 /***********************************************************************
1418  *           GetNumTasks   (KERNEL.152)
1419  */
1420 UINT16 WINAPI GetNumTasks16(void)
1421 {
1422     return nTaskCount;
1423 }
1424
1425
1426 /***********************************************************************
1427  *           GetTaskDS   (KERNEL.155)
1428  *
1429  * Note: this function apparently returns a DWORD with LOWORD == HIWORD.
1430  * I don't think we need to bother with this.
1431  */
1432 HINSTANCE16 WINAPI GetTaskDS16(void)
1433 {
1434     TDB *pTask;
1435
1436     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1437     return pTask->hInstance;
1438 }
1439
1440 /***********************************************************************
1441  *           GetDummyModuleHandleDS   (KERNEL.602)
1442  */
1443 WORD WINAPI GetDummyModuleHandleDS16(void)
1444 {
1445     TDB *pTask;
1446     WORD selector;
1447
1448     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1449     if (!(pTask->flags & TDBF_WIN32)) return 0;
1450     selector = GlobalHandleToSel16( pTask->hModule );
1451     CURRENT_DS = selector;
1452     return selector;
1453 }
1454
1455 /***********************************************************************
1456  *           IsTask   (KERNEL.320)
1457  */
1458 BOOL16 WINAPI IsTask16( HTASK16 hTask )
1459 {
1460     TDB *pTask;
1461
1462     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return FALSE;
1463     if (GlobalSize16( hTask ) < sizeof(TDB)) return FALSE;
1464     return (pTask->magic == TDB_MAGIC);
1465 }
1466
1467
1468 /***********************************************************************
1469  *           IsWinOldApTask16   (KERNEL.158)
1470  */
1471 BOOL16 WINAPI IsWinOldApTask16( HTASK16 hTask )
1472 {
1473     /* should return bit 0 of byte 0x48 in PSP */
1474     return FALSE;
1475 }
1476
1477 /***********************************************************************
1478  *           SetTaskSignalProc   (KERNEL.38)
1479  */
1480 FARPROC16 WINAPI SetTaskSignalProc( HTASK16 hTask, FARPROC16 proc )
1481 {
1482     TDB *pTask;
1483     FARPROC16 oldProc;
1484
1485     if (!hTask) hTask = GetCurrentTask();
1486     if (!(pTask = (TDB *)GlobalLock16( hTask ))) return NULL;
1487     oldProc = pTask->userhandler;
1488     pTask->userhandler = proc;
1489     return oldProc;
1490 }
1491
1492 /***********************************************************************
1493  *           TASK_CallTaskSignalProc
1494  */
1495 /* ### start build ### */
1496 extern WORD CALLBACK TASK_CallTo16_word_wwwww(FARPROC16,WORD,WORD,WORD,WORD,WORD);
1497 /* ### stop build ### */
1498 void TASK_CallTaskSignalProc( UINT16 uCode, HANDLE16 hTaskOrModule )
1499 {
1500     TDB *pTask = (TDB *)GlobalLock16( GetCurrentTask() );
1501     if ( !pTask || !pTask->userhandler ) return;
1502
1503     TASK_CallTo16_word_wwwww( pTask->userhandler,
1504                               hTaskOrModule, uCode, 0,
1505                               pTask->hInstance, pTask->hQueue );
1506 }
1507
1508 /***********************************************************************
1509  *           SetSigHandler   (KERNEL.140)
1510  */
1511 WORD WINAPI SetSigHandler16( FARPROC16 newhandler, FARPROC16* oldhandler,
1512                            UINT16 *oldmode, UINT16 newmode, UINT16 flag )
1513 {
1514     FIXME("(%p,%p,%p,%d,%d), unimplemented.\n",
1515           newhandler,oldhandler,oldmode,newmode,flag );
1516
1517     if (flag != 1) return 0;
1518     if (!newmode) newhandler = NULL;  /* Default handler */
1519     if (newmode != 4)
1520     {
1521         TDB *pTask;
1522
1523         if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return 0;
1524         if (oldmode) *oldmode = pTask->signal_flags;
1525         pTask->signal_flags = newmode;
1526         if (oldhandler) *oldhandler = pTask->sighandler;
1527         pTask->sighandler = newhandler;
1528     }
1529     return 0;
1530 }
1531
1532
1533 /***********************************************************************
1534  *           GlobalNotify   (KERNEL.154)
1535  *
1536  * Note that GlobalNotify does _not_ return the old NotifyProc
1537  * -- contrary to LocalNotify !!
1538  */
1539 VOID WINAPI GlobalNotify16( FARPROC16 proc )
1540 {
1541     TDB *pTask;
1542
1543     if (!(pTask = (TDB *)GlobalLock16( GetCurrentTask() ))) return;
1544     pTask->discardhandler = proc;
1545 }
1546
1547
1548 /***********************************************************************
1549  *           GetExePtr   (KERNEL.133)
1550  */
1551 static inline HMODULE16 GetExePtrHelper( HANDLE16 handle, HTASK16 *hTask )
1552 {
1553     char *ptr;
1554     HANDLE16 owner;
1555
1556       /* Check for module handle */
1557
1558     if (!(ptr = GlobalLock16( handle ))) return 0;
1559     if (((NE_MODULE *)ptr)->magic == IMAGE_OS2_SIGNATURE) return handle;
1560
1561       /* Search for this handle inside all tasks */
1562
1563     *hTask = hFirstTask;
1564     while (*hTask)
1565     {
1566         TDB *pTask = (TDB *)GlobalLock16( *hTask );
1567         if ((*hTask == handle) ||
1568             (pTask->hInstance == handle) ||
1569             (pTask->hQueue == handle) ||
1570             (pTask->hPDB == handle)) return pTask->hModule;
1571         *hTask = pTask->hNext;
1572     }
1573
1574       /* Check the owner for module handle */
1575
1576     owner = FarGetOwner16( handle );
1577     if (!(ptr = GlobalLock16( owner ))) return 0;
1578     if (((NE_MODULE *)ptr)->magic == IMAGE_OS2_SIGNATURE) return owner;
1579
1580       /* Search for the owner inside all tasks */
1581
1582     *hTask = hFirstTask;
1583     while (*hTask)
1584     {
1585         TDB *pTask = (TDB *)GlobalLock16( *hTask );
1586         if ((*hTask == owner) ||
1587             (pTask->hInstance == owner) ||
1588             (pTask->hQueue == owner) ||
1589             (pTask->hPDB == owner)) return pTask->hModule;
1590         *hTask = pTask->hNext;
1591     }
1592
1593     return 0;
1594 }
1595
1596 HMODULE16 WINAPI WIN16_GetExePtr( HANDLE16 handle )
1597 {
1598     HTASK16 hTask = 0;
1599     HMODULE16 hModule = GetExePtrHelper( handle, &hTask );
1600     STACK16FRAME *frame = CURRENT_STACK16;
1601     frame->ecx = hModule;
1602     if (hTask) frame->es = hTask;
1603     return hModule;
1604 }
1605
1606 HMODULE16 WINAPI GetExePtr( HANDLE16 handle )
1607 {
1608     HTASK16 hTask = 0;
1609     return GetExePtrHelper( handle, &hTask );
1610 }
1611
1612
1613 /***********************************************************************
1614  *           TaskFirst   (TOOLHELP.63)
1615  */
1616 BOOL16 WINAPI TaskFirst16( TASKENTRY *lpte )
1617 {
1618     lpte->hNext = hFirstTask;
1619     return TaskNext16( lpte );
1620 }
1621
1622
1623 /***********************************************************************
1624  *           TaskNext   (TOOLHELP.64)
1625  */
1626 BOOL16 WINAPI TaskNext16( TASKENTRY *lpte )
1627 {
1628     TDB *pTask;
1629     INSTANCEDATA *pInstData;
1630
1631     TRACE_(toolhelp)("(%p): task=%04x\n", lpte, lpte->hNext );
1632     if (!lpte->hNext) return FALSE;
1633     pTask = (TDB *)GlobalLock16( lpte->hNext );
1634     if (!pTask || pTask->magic != TDB_MAGIC) return FALSE;
1635     pInstData = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN( pTask->hInstance, 0 );
1636     lpte->hTask         = lpte->hNext;
1637     lpte->hTaskParent   = pTask->hParent;
1638     lpte->hInst         = pTask->hInstance;
1639     lpte->hModule       = pTask->hModule;
1640     lpte->wSS           = SELECTOROF( pTask->teb->cur_stack );
1641     lpte->wSP           = OFFSETOF( pTask->teb->cur_stack );
1642     lpte->wStackTop     = pInstData->stacktop;
1643     lpte->wStackMinimum = pInstData->stackmin;
1644     lpte->wStackBottom  = pInstData->stackbottom;
1645     lpte->wcEvents      = pTask->nEvents;
1646     lpte->hQueue        = pTask->hQueue;
1647     lstrcpynA( lpte->szModule, pTask->module_name, sizeof(lpte->szModule) );
1648     lpte->wPSPOffset    = 0x100;  /*??*/
1649     lpte->hNext         = pTask->hNext;
1650     return TRUE;
1651 }
1652
1653
1654 /***********************************************************************
1655  *           TaskFindHandle   (TOOLHELP.65)
1656  */
1657 BOOL16 WINAPI TaskFindHandle16( TASKENTRY *lpte, HTASK16 hTask )
1658 {
1659     lpte->hNext = hTask;
1660     return TaskNext16( lpte );
1661 }
1662
1663
1664 /***********************************************************************
1665  *           GetAppCompatFlags16   (KERNEL.354)
1666  */
1667 DWORD WINAPI GetAppCompatFlags16( HTASK16 hTask )
1668 {
1669     return GetAppCompatFlags( hTask );
1670 }
1671
1672
1673 /***********************************************************************
1674  *           GetAppCompatFlags   (USER32.206)
1675  */
1676 DWORD WINAPI GetAppCompatFlags( HTASK hTask )
1677 {
1678     TDB *pTask;
1679
1680     if (!hTask) hTask = GetCurrentTask();
1681     if (!(pTask=(TDB *)GlobalLock16( (HTASK16)hTask ))) return 0;
1682     if (GlobalSize16(hTask) < sizeof(TDB)) return 0;
1683     return pTask->compat_flags;
1684 }