loader/task.c

   1 /*
   2  * Task functions
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include "windows.h"
  11 #include "task.h"
  12 #include "callback.h"
  13 #include "dos_fs.h"
  14 #include "debugger.h"
  15 #include "global.h"
  16 #include "instance.h"
  17 #include "miscemu.h"
  18 #include "module.h"
  19 #include "neexe.h"
  20 #include "options.h"
  21 #include "selectors.h"
  22 #include "toolhelp.h"
  23 #include "stddebug.h"
  24 #include "debug.h"
  25 #include "dde_proc.h"
  26
  27   /* Min. number of thunks allocated when creating a new segment */
  28 #define MIN_THUNKS  32
  29
  30   /* 32-bit stack size for each task */
  31   /* Must not be greater than 64k, or MAKE_SEGPTR won't work */
  32 #define STACK32_SIZE 0x10000
  33
  34
  35 static HTASK hFirstTask = 0;
  36 static HTASK hCurrentTask = 0;
  37 static HTASK hTaskToKill = 0;
  38 static HTASK hLockedTask = 0;
  39 static WORD nTaskCount = 0;
  40 static HANDLE hDOSEnvironment = 0;
  41
  42   /* TASK_Reschedule() 16-bit entry point */
  43 static FARPROC TASK_RescheduleProc;
  44
  45 #ifdef WINELIB
  46 #define TASK_SCHEDULE()  TASK_Reschedule();
  47 #else
  48 #define TASK_SCHEDULE()  CallTo16_word_(TASK_RescheduleProc,0)
  49 #endif
  50
  51
  52 static HANDLE TASK_CreateDOSEnvironment(void);
  53
  54 /***********************************************************************
  55  *           TASK_Init
  56  */
  57 BOOL TASK_Init(void)
  58 {
  59     TASK_RescheduleProc = (FARPROC)GetWndProcEntry16( "TASK_Reschedule" );
  60     if (!(hDOSEnvironment = TASK_CreateDOSEnvironment()))
  61         fprintf( stderr, "Not enough memory for DOS Environment\n" );
  62     return (hDOSEnvironment != 0);
  63 }
  64
  65
  66 /***********************************************************************
  67  *           TASK_CreateDOSEnvironment
  68  *
  69  * Create the original DOS environment.
  70  */
  71 static HANDLE TASK_CreateDOSEnvironment(void)
  72 {
  73     static const char program_name[] = "KRNL386.EXE";
  74     char **e, *p;
  75     int initial_size, size;
  76     HANDLE handle;
  77
  78     extern char **environ;
  79     extern char WindowsDirectory[], SystemDirectory[];
  80
  81     /* DOS environment format:
  82      * ASCIIZ   string 1
  83      * ASCIIZ   string 2
  84      * ...
  85      * ASCIIZ   string n
  86      * ASCIIZ   PATH=xxx
  87      * ASCIIZ   windir=xxx
  88      * BYTE     0
  89      * WORD     1
  90      * ASCIIZ   program name (e.g. C:\WINDOWS\SYSTEM\KRNL386.EXE)
  91      */
  92
  93     /* First compute the size of the fixed part of the environment */
  94
  95     initial_size = 5 +                            /* PATH= */
  96                    strlen(WindowsPath) + 1 +      /* path value */
  97                    7 +                            /* windir= */
  98                    strlen(WindowsDirectory) + 1 + /* windir value */
  99                    1 +                            /* BYTE 0 at end */
 100                    sizeof(WORD) +                 /* WORD 1 */
 101                    strlen(SystemDirectory) + 1 +  /* program directory */
 102                    strlen(program_name) + 1;      /* program name */
 103
 104     /* Compute the total size of the Unix environment (except path) */
 105
 106     for (e = environ, size = initial_size; *e; e++)
 107     {
 108         if (strncasecmp(*e, "path=", 5))
 109         {
 110             int len = strlen(*e) + 1;
 111             if (size + len >= 32767)
 112             {
 113                 fprintf( stderr, "Warning: environment larger than 32k.\n" );
 114                 break;
 115             }
 116             size += len;
 117         }
 118     }
 119
 120
 121     /* Now allocate the environment */
 122
 123     if (!(handle = GlobalAlloc( GMEM_FIXED, size ))) return 0;
 124     p = (char *)GlobalLock( handle );
 125
 126     /* And fill it with the Unix environment */
 127
 128     for (e = environ, size = initial_size; *e; e++)
 129     {
 130         if (strncasecmp(*e, "path=", 5))
 131         {
 132             int len = strlen(*e) + 1;
 133             if (size + len >= 32767) break;
 134             strcpy( p, *e );
 135             size += len;
 136             p    += len;
 137         }
 138     }
 139
 140     /* Now add the path and Windows directory */
 141
 142     strcpy( p, "PATH=" );
 143     strcat( p, WindowsPath );
 144     p += strlen(p) + 1;
 145
 146     strcpy( p, "windir=" );
 147     strcat( p, WindowsDirectory );
 148     p += strlen(p) + 1;
 149
 150     /* Now add the program name */
 151
 152     *p++ = '\0';
 153     *(WORD *)p = 1;
 154     p += sizeof(WORD);
 155     strcpy( p, SystemDirectory );
 156     strcat( p, "\\" );
 157     strcat( p, program_name );
 158
 159     /* Display it */
 160
 161     p = (char *) GlobalLock( handle );
 162     dprintf_task(stddeb, "Master DOS environment at %p\n", p);
 163     for (; *p; p += strlen(p) + 1) dprintf_task(stddeb, "    %s\n", p);
 164     dprintf_task( stddeb, "Progname: %s\n", p+3 );
 165
 166     return handle;
 167 }
 168
 169
 170 /***********************************************************************
 171  *           TASK_LinkTask
 172  */
 173 static void TASK_LinkTask( HTASK hTask )
 174 {
 175     HTASK *prevTask;
 176     TDB *pTask;
 177
 178     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 179     prevTask = &hFirstTask;
 180     while (*prevTask)
 181     {
 182         TDB *prevTaskPtr = (TDB *)GlobalLock( *prevTask );
 183         if (prevTaskPtr->priority >= pTask->priority) break;
 184         prevTask = &prevTaskPtr->hNext;
 185     }
 186     pTask->hNext = *prevTask;
 187     *prevTask = hTask;
 188     nTaskCount++;
 189 }
 190
 191
 192 /***********************************************************************
 193  *           TASK_UnlinkTask
 194  */
 195 static void TASK_UnlinkTask( HTASK hTask )
 196 {
 197     HTASK *prevTask;
 198     TDB *pTask;
 199
 200     prevTask = &hFirstTask;
 201     while (*prevTask && (*prevTask != hTask))
 202     {
 203         pTask = (TDB *)GlobalLock( *prevTask );
 204         prevTask = &pTask->hNext;
 205     }
 206     if (*prevTask)
 207     {
 208         pTask = (TDB *)GlobalLock( *prevTask );
 209         *prevTask = pTask->hNext;
 210         pTask->hNext = 0;
 211         nTaskCount--;
 212     }
 213 }
 214
 215
 216 /***********************************************************************
 217  *           TASK_CreateThunks
 218  *
 219  * Create a thunk free-list in segment 'handle', starting from offset 'offset'
 220  * and containing 'count' entries.
 221  */
 222 static void TASK_CreateThunks( HGLOBAL handle, WORD offset, WORD count )
 223 {
 224     int i;
 225     WORD free;
 226     THUNKS *pThunk;
 227
 228     pThunk = (THUNKS *)((BYTE *)GlobalLock( handle ) + offset);
 229     pThunk->next = 0;
 230     pThunk->magic = THUNK_MAGIC;
 231     pThunk->free = (int)&pThunk->thunks - (int)pThunk;
 232     free = pThunk->free;
 233     for (i = 0; i < count-1; i++)
 234     {
 235         free += 8;  /* Offset of next thunk */
 236         pThunk->thunks[4*i] = free;
 237     }
 238     pThunk->thunks[4*i] = 0;  /* Last thunk */
 239 }
 240
 241
 242 /***********************************************************************
 243  *           TASK_AllocThunk
 244  *
 245  * Allocate a thunk for MakeProcInstance().
 246  */
 247 static SEGPTR TASK_AllocThunk( HTASK hTask )
 248 {
 249     TDB *pTask;
 250     THUNKS *pThunk;
 251     WORD sel, base;
 252
 253     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 254     sel = pTask->hCSAlias;
 255     pThunk = &pTask->thunks;
 256     base = (int)pThunk - (int)pTask;
 257     while (!pThunk->free)
 258     {
 259         sel = pThunk->next;
 260         if (!sel)  /* Allocate a new segment */
 261         {
 262             sel = GLOBAL_Alloc( GMEM_FIXED, sizeof(THUNKS) + (MIN_THUNKS-1)*8,
 263                                 pTask->hPDB, TRUE, FALSE, FALSE );
 264             if (!sel) return (SEGPTR)0;
 265             TASK_CreateThunks( sel, 0, MIN_THUNKS );
 266             pThunk->next = sel;
 267         }
 268         pThunk = (THUNKS *)GlobalLock( sel );
 269         base = 0;
 270     }
 271     base += pThunk->free;
 272     pThunk->free = *(WORD *)((BYTE *)pThunk + pThunk->free);
 273     return MAKELONG( base, sel );
 274 }
 275
 276
 277 /***********************************************************************
 278  *           TASK_FreeThunk
 279  *
 280  * Free a MakeProcInstance() thunk.
 281  */
 282 static BOOL TASK_FreeThunk( HTASK hTask, SEGPTR thunk )
 283 {
 284     TDB *pTask;
 285     THUNKS *pThunk;
 286     WORD sel, base;
 287
 288     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 289     sel = pTask->hCSAlias;
 290     pThunk = &pTask->thunks;
 291     base = (int)pThunk - (int)pTask;
 292     while (sel && (sel != HIWORD(thunk)))
 293     {
 294         sel = pThunk->next;
 295         pThunk = (THUNKS *)GlobalLock( sel );
 296         base = 0;
 297     }
 298     if (!sel) return FALSE;
 299     *(WORD *)((BYTE *)pThunk + LOWORD(thunk) - base) = pThunk->free;
 300     pThunk->free = LOWORD(thunk) - base;
 301     return TRUE;
 302 }
 303
 304
 305 /***********************************************************************
 306  *           TASK_CallToStart
 307  *
 308  * 32-bit entry point for a new task. This function is responsible for
 309  * setting up the registers and jumping to the 16-bit entry point.
 310  */
 311 static void TASK_CallToStart(void)
 312 {
 313     int cs_reg, ds_reg, ip_reg;
 314     TDB *pTask = (TDB *)GlobalLock( hCurrentTask );
 315     NE_MODULE *pModule = (NE_MODULE *)GlobalLock( pTask->hModule );
 316     SEGTABLEENTRY *pSegTable = NE_SEG_TABLE( pModule );
 317
 318     /* Registers at initialization must be:
 319      * ax   zero
 320      * bx   stack size in bytes
 321      * cx   heap size in bytes
 322      * si   previous app instance
 323      * di   current app instance
 324      * bp   zero
 325      * es   selector to the PSP
 326      * ds   dgroup of the application
 327      * ss   stack selector
 328      * sp   top of the stack
 329      */
 330
 331     cs_reg = pSegTable[pModule->cs - 1].selector;
 332     ip_reg = pModule->ip;
 333     ds_reg = pSegTable[pModule->dgroup - 1].selector;
 334 #ifndef WINELIB
 335 /* JBP: I doubt a CallTo16_regs_ is possible in libwine.a, and IF1632 is not
 336  *      allowed.
 337  */
 338     IF1632_Saved16_ss = pTask->ss;
 339     IF1632_Saved16_sp = pTask->sp;
 340     dprintf_task( stddeb, "Starting main program: cs:ip=%04x:%04x ds=%04x ss:sp=%04x:%04x\n",
 341                  cs_reg, ip_reg, ds_reg,
 342                  IF1632_Saved16_ss, IF1632_Saved16_sp);
 343
 344     CallTo16_regs_( (FARPROC)(cs_reg << 16 | ip_reg), ds_reg,
 345                    pTask->hPDB /*es*/, 0 /*bp*/, 0 /*ax*/,
 346                    pModule->stack_size /*bx*/, pModule->heap_size /*cx*/,
 347                    0 /*dx*/, 0 /*si*/, ds_reg /*di*/ );
 348 #else
 349     fprintf(stderr, "JBP: Ignoring main program: cs:ip=%04x:%04x ds=%04x ss:sp=%04x:%04x\n",
 350                  cs_reg, ip_reg, ds_reg,
 351                  pTask->ss, pTask->sp);
 352 #endif
 353     /* This should never return */
 354     fprintf( stderr, "TASK_CallToStart: Main program returned!\n" );
 355     TASK_KillCurrentTask( 1 );
 356 }
 357
 358
 359 /***********************************************************************
 360  *           TASK_CreateTask
 361  */
 362 HTASK TASK_CreateTask( HMODULE hModule, HANDLE hInstance, HANDLE hPrevInstance,
 363                        HANDLE hEnvironment, char *cmdLine, WORD cmdShow )
 364 {
 365     HTASK hTask;
 366     TDB *pTask;
 367     HANDLE hParentEnv;
 368     NE_MODULE *pModule;
 369     SEGTABLEENTRY *pSegTable;
 370     LPSTR name;
 371     char filename[256];
 372 #ifndef WINELIB32
 373     char *stack16Top, *stack32Top;
 374     STACK16FRAME *frame16;
 375     STACK32FRAME *frame32;
 376     extern DWORD CALL16_RetAddr_word;
 377 #endif
 378
 379     if (!(pModule = (NE_MODULE *)GlobalLock( hModule ))) return 0;
 380     pSegTable = NE_SEG_TABLE( pModule );
 381
 382       /* Allocate the task structure */
 383
 384     hTask = GLOBAL_Alloc( GMEM_FIXED | GMEM_ZEROINIT, sizeof(TDB),
 385                           hModule, FALSE, FALSE, FALSE );
 386     if (!hTask) return 0;
 387     pTask = (TDB *)GlobalLock( hTask );
 388
 389       /* Allocate the new environment block */
 390
 391     if (!(hParentEnv = hEnvironment))
 392     {
 393         TDB *pParent = (TDB *)GlobalLock( hCurrentTask );
 394         hParentEnv = pParent ? pParent->pdb.environment : hDOSEnvironment;
 395     }
 396     /* FIXME: do we really need to make a copy also when */
 397     /*        we don't use the parent environment? */
 398     if (!(hEnvironment = GlobalAlloc( GMEM_FIXED, GlobalSize( hParentEnv ) )))
 399     {
 400         GlobalFree( hTask );
 401         return 0;
 402     }
 403     memcpy( GlobalLock( hEnvironment ), GlobalLock( hParentEnv ),
 404             GlobalSize( hParentEnv ) );
 405
 406       /* Get current directory */
 407
 408     GetModuleFileName( hModule, filename, sizeof(filename) );
 409     name = strrchr(filename, '\\');
 410     if (name) *(name+1) = 0;
 411
 412       /* Fill the task structure */
 413
 414     pTask->nEvents       = 1;  /* So the task can be started */
 415     pTask->hSelf         = hTask;
 416     pTask->flags         = 0;
 417     pTask->version       = pModule->expected_version;
 418     pTask->hInstance     = hInstance;
 419     pTask->hPrevInstance = hPrevInstance;
 420     pTask->hModule       = hModule;
 421     pTask->hParent       = hCurrentTask;
 422 #ifdef WINELIB
 423     pTask->curdrive      = 'C' - 'A' + 0x80;
 424 #else
 425     pTask->curdrive      = filename[0] - 'A' + 0x80;
 426 #endif
 427     pTask->magic         = TDB_MAGIC;
 428     pTask->nCmdShow      = cmdShow;
 429     strcpy( pTask->curdir, filename+2 );
 430
 431       /* Create the thunks block */
 432
 433     TASK_CreateThunks( hTask, (int)&pTask->thunks - (int)pTask, 7 );
 434
 435       /* Copy the module name */
 436
 437     name = MODULE_GetModuleName( hModule );
 438     strncpy( pTask->module_name, name, sizeof(pTask->module_name) );
 439
 440       /* Fill the PDB */
 441
 442     pTask->pdb.int20 = 0x20cd;
 443     pTask->pdb.dispatcher[0] = 0x9a;  /* ljmp */
 444     *(DWORD *)&pTask->pdb.dispatcher[1] = MODULE_GetEntryPoint( GetModuleHandle("KERNEL"), 102 );  /* KERNEL.102 is DOS3Call() */
 445 #ifndef WINELIB
 446     pTask->pdb.savedint22 = INT_GetHandler( 0x22 );
 447     pTask->pdb.savedint23 = INT_GetHandler( 0x23 );
 448     pTask->pdb.savedint24 = INT_GetHandler( 0x24 );
 449 #endif
 450     pTask->pdb.environment = hEnvironment;
 451     strncpy( pTask->pdb.cmdLine + 1, cmdLine, 126 );
 452     pTask->pdb.cmdLine[127] = '\0';
 453     pTask->pdb.cmdLine[0] = strlen( pTask->pdb.cmdLine + 1 );
 454
 455       /* Get the compatibility flags */
 456
 457     pTask->compat_flags = GetProfileInt( name, "Compatibility", 0 );
 458
 459       /* Allocate a selector for the PDB */
 460
 461     pTask->hPDB = GLOBAL_CreateBlock( GMEM_FIXED, &pTask->pdb, sizeof(PDB),
 462                                       hModule, FALSE, FALSE, FALSE, NULL );
 463
 464       /* Allocate a code segment alias for the TDB */
 465
 466     pTask->hCSAlias = GLOBAL_CreateBlock( GMEM_FIXED, (void *)pTask,
 467                                           sizeof(TDB), pTask->hPDB, TRUE,
 468                                           FALSE, FALSE, NULL );
 469
 470       /* Set the owner of the environment block */
 471
 472     FarSetOwner( pTask->pdb.environment, pTask->hPDB );
 473
 474       /* Default DTA overwrites command-line */
 475
 476     pTask->dta = MAKELONG( (int)&pTask->pdb.cmdLine - (int)&pTask->pdb,
 477                            pTask->hPDB );
 478
 479       /* Allocate the 32-bit stack */
 480
 481 #ifndef WINELIB
 482     pTask->hStack32 = GLOBAL_Alloc( GMEM_FIXED, STACK32_SIZE, pTask->hPDB,
 483                                     FALSE, FALSE, FALSE );
 484
 485       /* Create the 32-bit stack frame */
 486
 487     *(DWORD *)GlobalLock(pTask->hStack32) = 0xDEADBEEF;
 488     stack32Top = (char*)GlobalLock(pTask->hStack32) + STACK32_SIZE;
 489     frame32 = (STACK32FRAME *)stack32Top - 1;
 490     frame32->saved_esp = (DWORD)stack32Top;
 491     frame32->edi = 0;
 492     frame32->esi = 0;
 493     frame32->edx = 0;
 494     frame32->ecx = 0;
 495     frame32->ebx = 0;
 496     frame32->ebp = 0;
 497     frame32->retaddr = (DWORD)TASK_CallToStart;
 498     frame32->codeselector = WINE_CODE_SELECTOR;
 499     pTask->esp = (DWORD)frame32;
 500
 501       /* Create the 16-bit stack frame */
 502
 503     pTask->ss = hInstance;
 504     pTask->sp = ((pModule->sp != 0) ? pModule->sp :
 505                  pSegTable[pModule->ss-1].minsize + pModule->stack_size) & ~1;
 506     stack16Top = (char *)PTR_SEG_OFF_TO_LIN( pTask->ss, pTask->sp );
 507     frame16 = (STACK16FRAME *)stack16Top - 1;
 508     frame16->saved_ss = 0; /*pTask->ss;*/
 509     frame16->saved_sp = 0; /*pTask->sp;*/
 510     frame16->ds = frame16->es = pTask->hInstance;
 511     frame16->entry_point = 0;
 512     frame16->ordinal_number = 24;  /* WINPROCS.24 is TASK_Reschedule */
 513     frame16->dll_id = 24; /* WINPROCS */
 514     frame16->bp = 0;
 515     frame16->ip = LOWORD( CALL16_RetAddr_word );
 516     frame16->cs = HIWORD( CALL16_RetAddr_word );
 517     pTask->sp -= sizeof(STACK16FRAME);
 518
 519       /* If there's no 16-bit stack yet, use a part of the new task stack */
 520       /* This is only needed to have a stack to switch from on the first  */
 521       /* call to DirectedYield(). */
 522
 523     if (!IF1632_Saved16_ss)
 524     {
 525         IF1632_Saved16_ss = pTask->ss;
 526         IF1632_Saved16_sp = pTask->sp;
 527     }
 528
 529       /* Add a breakpoint at the start of the task */
 530
 531     if (Options.debug)
 532     {
 533         DBG_ADDR addr = { pSegTable[pModule->cs-1].selector, pModule->ip };
 534         fprintf( stderr, "Task '%s': ", name );
 535         DEBUG_AddBreakpoint( &addr );
 536     }
 537 #endif
 538
 539       /* Add the task to the linked list */
 540
 541     TASK_LinkTask( hTask );
 542
 543     dprintf_task( stddeb, "CreateTask: module='%s' cmdline='%s' task="NPFMT"\n",
 544                   name, cmdLine, hTask );
 545
 546     return hTask;
 547 }
 548
 549
 550 /***********************************************************************
 551  *           TASK_DeleteTask
 552  */
 553 static void TASK_DeleteTask( HTASK hTask )
 554 {
 555     TDB *pTask;
 556
 557     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 558
 559       /* Free the task module */
 560
 561     FreeModule( pTask->hModule );
 562
 563       /* Free all memory used by this task (including the 32-bit stack, */
 564       /* the environment block and the thunk segments). */
 565
 566     GlobalFreeAll( pTask->hPDB );
 567
 568       /* Free the selector aliases */
 569
 570     GLOBAL_FreeBlock( pTask->hCSAlias );
 571     GLOBAL_FreeBlock( pTask->hPDB );
 572
 573       /* Free the task structure itself */
 574
 575     GlobalFree( hTask );
 576 }
 577
 578
 579 /***********************************************************************
 580  *           TASK_KillCurrentTask
 581  *
 582  * Kill the currently running task. As it's not possible to kill the
 583  * current task like this, it is simply marked for destruction, and will
 584  * be killed when either TASK_Reschedule or this function is called again
 585  * in the context of another task.
 586  */
 587 void TASK_KillCurrentTask( int exitCode )
 588 {
 589     if (hTaskToKill && (hTaskToKill != hCurrentTask))
 590     {
 591         /* If another task is already marked for destruction, */
 592         /* we call kill it now, as we are in another context. */
 593         TASK_DeleteTask( hTaskToKill );
 594     }
 595
 596     if (nTaskCount <= 1)
 597     {
 598         dprintf_task( stddeb, "Killing the last task, exiting\n" );
 599         exit(0);
 600     }
 601
 602     /* Remove the task from the list to be sure we never switch back to it */
 603     TASK_UnlinkTask( hCurrentTask );
 604
 605     hTaskToKill = hCurrentTask;
 606     hLockedTask = 0;
 607     Yield();
 608     /* We never return from Yield() */
 609 }
 610
 611
 612 /***********************************************************************
 613  *           TASK_Reschedule
 614  *
 615  * This is where all the magic of task-switching happens!
 616  *
 617  * This function should only be called via the TASK_SCHEDULE() macro, to make
 618  * sure that all the context is saved correctly.
 619  */
 620 void TASK_Reschedule(void)
 621 {
 622     TDB *pOldTask = NULL, *pNewTask;
 623     HTASK hTask = 0;
 624
 625 #ifdef CONFIG_IPC
 626     dde_reschedule();
 627 #endif
 628       /* First check if there's a task to kill */
 629
 630     if (hTaskToKill && (hTaskToKill != hCurrentTask))
 631     {
 632         TASK_DeleteTask( hTaskToKill );
 633         hTaskToKill = 0;
 634     }
 635
 636       /* If current task is locked, simply return */
 637
 638     if (hLockedTask) return;
 639
 640       /* Find a task to yield to */
 641
 642     pOldTask = (TDB *)GlobalLock( hCurrentTask );
 643     if (pOldTask && pOldTask->hYieldTo)
 644     {
 645         /* If a task is stored in hYieldTo of the current task (put there */
 646         /* by DirectedYield), yield to it only if it has events pending.  */
 647         hTask = pOldTask->hYieldTo;
 648         if (!(pNewTask = (TDB *)GlobalLock( hTask )) || !pNewTask->nEvents)
 649             hTask = 0;
 650     }
 651
 652     if (!hTask)
 653     {
 654         hTask = hFirstTask;
 655         while (hTask)
 656         {
 657             pNewTask = (TDB *)GlobalLock( hTask );
 658             if (pNewTask->nEvents && (hTask != hCurrentTask)) break;
 659             hTask = pNewTask->hNext;
 660         }
 661     }
 662
 663      /* If there's a task to kill, switch to any other task, */
 664      /* even if it doesn't have events pending. */
 665
 666     if (!hTask && hTaskToKill) hTask = hFirstTask;
 667
 668     if (!hTask) return;  /* Do nothing */
 669
 670     pNewTask = (TDB *)GlobalLock( hTask );
 671     dprintf_task( stddeb, "Switching to task "NPFMT" (%.8s)\n",
 672                   hTask, pNewTask->module_name );
 673
 674       /* Save the stacks of the previous task (if any) */
 675
 676 #ifndef WINELIB /* FIXME: JBP: IF1632 not allowed in libwine.a */
 677     if (pOldTask)
 678     {
 679         pOldTask->ss  = IF1632_Saved16_ss;
 680         pOldTask->sp  = IF1632_Saved16_sp;
 681         pOldTask->esp = IF1632_Saved32_esp;
 682     }
 683     else IF1632_Original32_esp = IF1632_Saved32_esp;
 684 #endif
 685
 686      /* Make the task the last in the linked list (round-robin scheduling) */
 687
 688     pNewTask->priority++;
 689     TASK_UnlinkTask( hTask );
 690     TASK_LinkTask( hTask );
 691     pNewTask->priority--;
 692
 693       /* Switch to the new stack */
 694
 695     hCurrentTask = hTask;
 696 #ifndef WINELIB /* FIXME: JBP: IF1632 not allowed in libwine.a */
 697     IF1632_Saved16_ss   = pNewTask->ss;
 698     IF1632_Saved16_sp   = pNewTask->sp;
 699     IF1632_Saved32_esp  = pNewTask->esp;
 700     IF1632_Stack32_base = WIN16_GlobalLock( pNewTask->hStack32 );
 701 #endif
 702 }
 703
 704
 705 /***********************************************************************
 706  *           InitTask  (KERNEL.91)
 707  */
 708 void InitTask( struct sigcontext_struct context )
 709 {
 710     static int firstTask = 1;
 711     TDB *pTask;
 712     NE_MODULE *pModule;
 713     SEGTABLEENTRY *pSegTable;
 714     INSTANCEDATA *pinstance;
 715     LONG stacklow, stackhi;
 716
 717     EAX_reg(&context) = 0;
 718     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return;
 719     if (!(pModule = (NE_MODULE *)GlobalLock( pTask->hModule ))) return;
 720
 721     if (firstTask)
 722     {
 723         extern BOOL WIDGETS_Init(void);
 724         extern BOOL WIN_CreateDesktopWindow(void);
 725
 726         /* Perform global initialisations that need a task context */
 727
 728           /* Initialize built-in window classes */
 729         if (!WIDGETS_Init()) return;
 730
 731           /* Create desktop window */
 732         if (!WIN_CreateDesktopWindow()) return;
 733
 734         firstTask = 0;
 735     }
 736
 737 #ifndef WINELIB
 738     NE_InitializeDLLs( pTask->hModule );
 739 #endif
 740
 741     /* Registers on return are:
 742      * ax     1 if OK, 0 on error
 743      * cx     stack limit in bytes
 744      * dx     cmdShow parameter
 745      * si     instance handle of the previous instance
 746      * di     instance handle of the new task
 747      * es:bx  pointer to command-line inside PSP
 748      */
 749     EAX_reg(&context) = 1;
 750     EBX_reg(&context) = 0x81;
 751     ECX_reg(&context) = pModule->stack_size;
 752     EDX_reg(&context) = pTask->nCmdShow;
 753     ESI_reg(&context) = (DWORD)pTask->hPrevInstance;
 754     EDI_reg(&context) = (DWORD)pTask->hInstance;
 755     ES_reg (&context) = (WORD)pTask->hPDB;
 756
 757     /* Initialize the local heap */
 758     if ( pModule->heap_size )
 759     {
 760         LocalInit( pTask->hInstance, 0, pModule->heap_size );
 761     }
 762
 763
 764     /* Initialize the INSTANCEDATA structure */
 765     pSegTable = NE_SEG_TABLE( pModule );
 766     stacklow = pSegTable[pModule->ss - 1].minsize;
 767     stackhi  = stacklow + pModule->stack_size;
 768     if (stackhi > 0xffff) stackhi = 0xffff;
 769     pinstance = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN(CURRENT_DS, 0);
 770     pinstance->stackbottom = stackhi; /* yup, that's right. Confused me too. */
 771     pinstance->stacktop    = stacklow;
 772 #ifndef WINELIB /* FIXME: JBP: IF1632 not allowed in libwine.a */
 773     pinstance->stackmin    = IF1632_Saved16_sp;
 774 #endif
 775 }
 776
 777
 778 /***********************************************************************
 779  *           WaitEvent  (KERNEL.30)
 780  */
 781 BOOL WaitEvent( HTASK hTask )
 782 {
 783     TDB *pTask;
 784
 785     if (!hTask) hTask = hCurrentTask;
 786     pTask = (TDB *)GlobalLock( hTask );
 787     if (pTask->nEvents > 0)
 788     {
 789         pTask->nEvents--;
 790         return FALSE;
 791     }
 792     TASK_SCHEDULE();
 793     /* When we get back here, we have an event (or the task is the only one) */
 794     if (pTask->nEvents > 0) pTask->nEvents--;
 795     return TRUE;
 796 }
 797
 798
 799 /***********************************************************************
 800  *           PostEvent  (KERNEL.31)
 801  */
 802 void PostEvent( HTASK hTask )
 803 {
 804     TDB *pTask;
 805
 806     if (!hTask) hTask = hCurrentTask;
 807     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 808     pTask->nEvents++;
 809 }
 810
 811
 812 /***********************************************************************
 813  *           SetPriority  (KERNEL.32)
 814  */
 815 void SetPriority( HTASK hTask, int delta )
 816 {
 817     TDB *pTask;
 818     int newpriority;
 819
 820     if (!hTask) hTask = hCurrentTask;
 821     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 822     newpriority = pTask->priority + delta;
 823     if (newpriority < -32) newpriority = -32;
 824     else if (newpriority > 15) newpriority = 15;
 825
 826     pTask->priority = newpriority + 1;
 827     TASK_UnlinkTask( hTask );
 828     TASK_LinkTask( hTask );
 829     pTask->priority--;
 830 }
 831
 832
 833 /***********************************************************************
 834  *           LockCurrentTask  (KERNEL.33)
 835  */
 836 HTASK LockCurrentTask( BOOL bLock )
 837 {
 838     if (bLock) hLockedTask = hCurrentTask;
 839     else hLockedTask = 0;
 840     return hLockedTask;
 841 }
 842
 843
 844 /***********************************************************************
 845  *           IsTaskLocked  (KERNEL.122)
 846  */
 847 WORD IsTaskLocked(void)
 848 {
 849     return hLockedTask;
 850 }
 851
 852
 853 /***********************************************************************
 854  *           OldYield  (KERNEL.117)
 855  */
 856 void OldYield(void)
 857 {
 858     TDB *pCurTask;
 859
 860     pCurTask = (TDB *)GlobalLock( hCurrentTask );
 861     if (pCurTask) pCurTask->nEvents++;  /* Make sure we get back here */
 862     TASK_SCHEDULE();
 863     if (pCurTask) pCurTask->nEvents--;
 864 }
 865
 866
 867 /***********************************************************************
 868  *           DirectedYield  (KERNEL.150)
 869  */
 870 void DirectedYield( HTASK hTask )
 871 {
 872     TDB *pCurTask;
 873
 874     if ((pCurTask = (TDB *)GlobalLock( hCurrentTask )) != NULL)
 875         pCurTask->hYieldTo = hTask;
 876
 877     OldYield();
 878 }
 879
 880
 881 /***********************************************************************
 882  *           Yield  (KERNEL.29)
 883  */
 884 void Yield(void)
 885 {
 886     DirectedYield( 0 );
 887 }
 888
 889
 890 /***********************************************************************
 891  *           MakeProcInstance  (KERNEL.51)
 892  */
 893 FARPROC MakeProcInstance( FARPROC func, HANDLE hInstance )
 894 {
 895     BYTE *thunk;
 896     SEGPTR thunkaddr;
 897
 898     thunkaddr = TASK_AllocThunk( hCurrentTask );
 899     if (!thunkaddr) return (FARPROC)0;
 900     thunk = PTR_SEG_TO_LIN( thunkaddr );
 901
 902     dprintf_task( stddeb, "MakeProcInstance(%08lx,"NPFMT"): got thunk %08lx\n",
 903                   (SEGPTR)func, hInstance, (SEGPTR)thunkaddr );
 904
 905     *thunk++ = 0xb8;    /* movw instance, %ax */
 906 #ifndef WINELIB
 907     *thunk++ = (BYTE)(hInstance & 0xff);
 908     *thunk++ = (BYTE)(hInstance >> 8);
 909 #endif
 910     *thunk++ = 0xea;    /* ljmp func */
 911     *(DWORD *)thunk = (DWORD)func;
 912     return (FARPROC)thunkaddr;
 913 }
 914
 915
 916 /***********************************************************************
 917  *           FreeProcInstance  (KERNEL.52)
 918  */
 919 void FreeProcInstance( FARPROC func )
 920 {
 921     dprintf_task( stddeb, "FreeProcInstance(%08lx)\n", (SEGPTR)func );
 922     TASK_FreeThunk( hCurrentTask, (SEGPTR)func );
 923 }
 924
 925
 926 /**********************************************************************
 927  *          GetCodeHandle    (KERNEL.93)
 928  */
 929 HANDLE GetCodeHandle( FARPROC proc )
 930 {
 931     HANDLE handle;
 932     BYTE *thunk = (BYTE *)PTR_SEG_TO_LIN( proc );
 933
 934     /* Return the code segment containing 'proc'. */
 935     /* Not sure if this is really correct (shouldn't matter that much). */
 936
 937     /* Check if it is really a thunk */
 938     if ((thunk[0] == 0xb8) && (thunk[3] == 0xea))
 939         handle = GlobalHandle( thunk[6] + (thunk[7] << 8) );
 940     else
 941         handle = GlobalHandle( HIWORD(proc) );
 942
 943     printf( "STUB: GetCodeHandle(%08lx) returning "NPFMT"\n",
 944             (DWORD)proc, handle );
 945     return handle;
 946 }
 947
 948
 949 /***********************************************************************
 950  *           SetTaskQueue  (KERNEL.34)
 951  */
 952 HGLOBAL SetTaskQueue( HANDLE hTask, HGLOBAL hQueue )
 953 {
 954     HGLOBAL hPrev;
 955     TDB *pTask;
 956
 957     if (!hTask) hTask = hCurrentTask;
 958     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 959     hPrev = pTask->hQueue;
 960     pTask->hQueue = hQueue;
 961     return hPrev;
 962 }
 963
 964
 965 /***********************************************************************
 966  *           GetTaskQueue  (KERNEL.35)
 967  */
 968 HGLOBAL GetTaskQueue( HANDLE hTask )
 969 {
 970     TDB *pTask;
 971
 972     if (!hTask) hTask = hCurrentTask;
 973     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 974     return pTask->hQueue;
 975 }
 976
 977
 978 /***********************************************************************
 979  *           GetTaskQueueDS  (KERNEL.118)
 980  */
 981 #ifndef WINELIB
 982 void GetTaskQueueDS( struct sigcontext_struct context )
 983 {
 984     DS_reg(&context) = GlobalHandleToSel( GetTaskQueue(0) );
 985 }
 986 #endif  /* WINELIB */
 987
 988
 989 /***********************************************************************
 990  *           GetTaskQueueES  (KERNEL.119)
 991  */
 992 #ifndef WINELIB
 993 void GetTaskQueueES( struct sigcontext_struct context )
 994 {
 995     ES_reg(&context) = GlobalHandleToSel( GetTaskQueue(0) );
 996 }
 997 #endif  /* WINELIB */
 998
 999
1000 /***********************************************************************
1001  *           GetCurrentTask   (KERNEL.36)
1002  */
1003 HTASK GetCurrentTask(void)
1004 {
1005       /* Undocumented: first task is returned in high word */
1006 #ifdef WINELIB32
1007     return hCurrentTask;
1008 #else
1009     return MAKELONG( hCurrentTask, hFirstTask );
1010 #endif
1011 }
1012
1013
1014 /***********************************************************************
1015  *           GetCurrentPDB   (KERNEL.37)
1016  */
1017 HANDLE GetCurrentPDB(void)
1018 {
1019     TDB *pTask;
1020
1021     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
1022     return pTask->hPDB;
1023 }
1024
1025
1026 /***********************************************************************
1027  *           GetInstanceData   (KERNEL.54)
1028  */
1029 int GetInstanceData( HANDLE instance, WORD buffer, int len )
1030 {
1031     char *ptr = (char *)GlobalLock( instance );
1032     if (!ptr || !len) return 0;
1033     if ((int)buffer + len >= 0x10000) len = 0x10000 - buffer;
1034     memcpy( ptr + buffer, (char *)GlobalLock( CURRENT_DS ) + buffer, len );
1035     return len;
1036 }
1037
1038
1039 /***********************************************************************
1040  *           GetDOSEnvironment   (KERNEL.131)
1041  */
1042 SEGPTR GetDOSEnvironment(void)
1043 {
1044     TDB *pTask;
1045
1046     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
1047     return (SEGPTR)WIN16_GlobalLock( pTask->pdb.environment );
1048 }
1049
1050
1051 /***********************************************************************
1052  *           GetNumTasks   (KERNEL.152)
1053  */
1054 WORD GetNumTasks(void)
1055 {
1056     return nTaskCount;
1057 }
1058
1059
1060 /***********************************************************************
1061  *           GetTaskDS   (KERNEL.155)
1062  */
1063 HINSTANCE GetTaskDS(void)
1064 {
1065     TDB *pTask;
1066
1067     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
1068     return pTask->hInstance;
1069 }
1070
1071
1072 /***********************************************************************
1073  *           IsTask   (KERNEL.320)
1074  */
1075 BOOL IsTask( HTASK hTask )
1076 {
1077     TDB *pTask;
1078
1079     if (!(pTask = (TDB *)GlobalLock( hTask ))) return FALSE;
1080     if (GlobalSize( hTask ) < sizeof(TDB)) return FALSE;
1081     return (pTask->magic == TDB_MAGIC);
1082 }
1083
1084
1085 /***********************************************************************
1086  *           GetExePtr   (KERNEL.133)
1087  */
1088 HMODULE GetExePtr( HANDLE handle )
1089 {
1090     char *ptr;
1091     HTASK hTask;
1092     HANDLE owner;
1093
1094       /* Check for module handle */
1095
1096     if (!(ptr = GlobalLock( handle ))) return 0;
1097     if (((NE_MODULE *)ptr)->magic == NE_SIGNATURE) return handle;
1098
1099       /* Check the owner for module handle */
1100
1101 #ifndef WINELIB
1102     owner = FarGetOwner( handle );
1103 #else
1104     owner = NULL;
1105     fprintf(stderr,"JBP: FarGetOwner() ignored.\n");
1106 #endif
1107     if (!(ptr = GlobalLock( owner ))) return 0;
1108     if (((NE_MODULE *)ptr)->magic == NE_SIGNATURE) return owner;
1109
1110       /* Search for this handle and its owner inside all tasks */
1111
1112     hTask = hFirstTask;
1113     while (hTask)
1114     {
1115         TDB *pTask = (TDB *)GlobalLock( hTask );
1116         if ((hTask == handle) ||
1117             (pTask->hInstance == handle) ||
1118             (pTask->hQueue == handle) ||
1119             (pTask->hPDB == handle)) return pTask->hModule;
1120         if ((hTask == owner) ||
1121             (pTask->hInstance == owner) ||
1122             (pTask->hQueue == owner) ||
1123             (pTask->hPDB == owner)) return pTask->hModule;
1124         hTask = pTask->hNext;
1125     }
1126     return 0;
1127 }
1128
1129
1130 /***********************************************************************
1131  *           TaskFirst   (TOOLHELP.63)
1132  */
1133 BOOL TaskFirst( TASKENTRY *lpte )
1134 {
1135     lpte->hNext = hFirstTask;
1136     return TaskNext( lpte );
1137 }
1138
1139
1140 /***********************************************************************
1141  *           TaskNext   (TOOLHELP.64)
1142  */
1143 BOOL TaskNext( TASKENTRY *lpte )
1144 {
1145     TDB *pTask;
1146     INSTANCEDATA *pInstData;
1147
1148     dprintf_toolhelp( stddeb, "TaskNext(%p): task="NPFMT"\n", lpte, lpte->hNext );
1149     if (!lpte->hNext) return FALSE;
1150     pTask = (TDB *)GlobalLock( lpte->hNext );
1151     if (!pTask || pTask->magic != TDB_MAGIC) return FALSE;
1152     pInstData = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN( pTask->hInstance, 0 );
1153     lpte->hTask         = lpte->hNext;
1154     lpte->hTaskParent   = pTask->hParent;
1155     lpte->hInst         = pTask->hInstance;
1156     lpte->hModule       = pTask->hModule;
1157     lpte->wSS           = pTask->ss;
1158     lpte->wSP           = pTask->sp;
1159     lpte->wStackTop     = pInstData->stacktop;
1160     lpte->wStackMinimum = pInstData->stackmin;
1161     lpte->wStackBottom  = pInstData->stackbottom;
1162     lpte->wcEvents      = pTask->nEvents;
1163     lpte->hQueue        = pTask->hQueue;
1164     strncpy( lpte->szModule, pTask->module_name, 8 );
1165     lpte->szModule[8]   = '\0';
1166     lpte->wPSPOffset    = 0x100;  /*??*/
1167     lpte->hNext         = pTask->hNext;
1168     return TRUE;
1169 }
1170
1171
1172 /***********************************************************************
1173  *           TaskFindHandle   (TOOLHELP.65)
1174  */
1175 BOOL TaskFindHandle( TASKENTRY *lpte, HTASK hTask )
1176 {
1177     lpte->hNext = hTask;
1178     return TaskNext( lpte );
1179 }