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 "directory.h"
  14 #include "dos_fs.h"
  15 #include "file.h"
  16 #include "debugger.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 "options.h"
  24 #include "selectors.h"
  25 #include "toolhelp.h"
  26 #include "stddebug.h"
  27 #include "debug.h"
  28 #include "dde_proc.h"
  29
  30   /* Min. number of thunks allocated when creating a new segment */
  31 #define MIN_THUNKS  32
  32
  33   /* 32-bit stack size for each task */
  34   /* Must not be greater than 64k, or MAKE_SEGPTR won't work */
  35 #define STACK32_SIZE 0x10000
  36
  37 /* ------ Internal variables ------ */
  38
  39 static HTASK hFirstTask = 0;
  40 static HTASK hCurrentTask = 0;
  41 static HTASK hTaskToKill = 0;
  42 static HTASK hLockedTask = 0;
  43 static WORD nTaskCount = 0;
  44 static HANDLE hDOSEnvironment = 0;
  45
  46 /* ------ Internal declarations ------ */
  47
  48   /* TASK_Reschedule() 16-bit entry point */
  49 static FARPROC TASK_RescheduleProc;
  50
  51 #ifdef WINELIB
  52 #define TASK_SCHEDULE()  TASK_Reschedule();
  53 #else
  54 #define TASK_SCHEDULE()  CallTo16_word_(TASK_RescheduleProc,0)
  55 #endif
  56
  57 static HANDLE TASK_CreateDOSEnvironment(void);
  58
  59 /***********************************************************************
  60  *           TASK_Init
  61  */
  62 BOOL TASK_Init(void)
  63 {
  64     TASK_RescheduleProc = (FARPROC)GetWndProcEntry16( "TASK_Reschedule" );
  65     if (!(hDOSEnvironment = TASK_CreateDOSEnvironment()))
  66         fprintf( stderr, "Not enough memory for DOS Environment\n" );
  67     return (hDOSEnvironment != 0);
  68 }
  69
  70
  71 /***********************************************************************
  72  *           TASK_CreateDOSEnvironment
  73  *
  74  * Create the original DOS environment.
  75  */
  76 static HANDLE TASK_CreateDOSEnvironment(void)
  77 {
  78     static const char program_name[] = "KRNL386.EXE";
  79     char **e, *p;
  80     int initial_size, size, i, winpathlen, windirlen, sysdirlen;
  81     HANDLE handle;
  82
  83     extern char **environ;
  84
  85     /* DOS environment format:
  86      * ASCIIZ   string 1
  87      * ASCIIZ   string 2
  88      * ...
  89      * ASCIIZ   string n
  90      * ASCIIZ   PATH=xxx
  91      * ASCIIZ   windir=xxx
  92      * BYTE     0
  93      * WORD     1
  94      * ASCIIZ   program name (e.g. C:\WINDOWS\SYSTEM\KRNL386.EXE)
  95      */
  96
  97     /* First compute the size of the fixed part of the environment */
  98
  99     for (i = winpathlen = 0; ; i++)
 100     {
 101         int len = DIR_GetDosPath( i, NULL, 0 );
 102         if (!len) break;
 103         winpathlen += len + 1;
 104     }
 105     if (!winpathlen) winpathlen = 1;
 106     windirlen  = GetWindowsDirectory( NULL, 0 ) + 1;
 107     sysdirlen  = GetSystemDirectory( NULL, 0 ) + 1;
 108     initial_size = 5 + winpathlen +           /* PATH=xxxx */
 109                    7 + windirlen +            /* windir=xxxx */
 110                    1 +                        /* BYTE 0 at end */
 111                    sizeof(WORD) +             /* WORD 1 */
 112                    sysdirlen +                /* program directory */
 113                    strlen(program_name) + 1;  /* program name */
 114
 115     /* Compute the total size of the Unix environment (except path) */
 116
 117     for (e = environ, size = initial_size; *e; e++)
 118     {
 119         if (lstrncmpi(*e, "path=", 5))
 120         {
 121             int len = strlen(*e) + 1;
 122             if (size + len >= 32767)
 123             {
 124                 fprintf( stderr, "Warning: environment larger than 32k.\n" );
 125                 break;
 126             }
 127             size += len;
 128         }
 129     }
 130
 131
 132     /* Now allocate the environment */
 133
 134     if (!(handle = GlobalAlloc( GMEM_FIXED, size ))) return 0;
 135     p = (char *)GlobalLock( handle );
 136
 137     /* And fill it with the Unix environment */
 138
 139     for (e = environ, size = initial_size; *e; e++)
 140     {
 141         if (lstrncmpi(*e, "path=", 5))
 142         {
 143             int len = strlen(*e) + 1;
 144             if (size + len >= 32767) break;
 145             strcpy( p, *e );
 146             size += len;
 147             p    += len;
 148         }
 149     }
 150
 151     /* Now add the path and Windows directory */
 152
 153     strcpy( p, "PATH=" );
 154     for (i = 0, p += 5; ; i++)
 155     {
 156         if (!DIR_GetDosPath( i, p, winpathlen )) break;
 157         p += strlen(p);
 158         *p++ = ';';
 159     }
 160     if (p[-1] == ';') p[-1] = '\0';
 161     else p++;
 162
 163     strcpy( p, "windir=" );
 164     GetWindowsDirectory( p + 7, windirlen );
 165     p += 7 + windirlen;
 166
 167     /* Now add the program name */
 168
 169     *p++ = '\0';
 170     *(WORD *)p = 1;
 171     p += sizeof(WORD);
 172     GetSystemDirectory( p, sysdirlen );
 173     strcat( p, "\\" );
 174     strcat( p, program_name );
 175
 176     /* Display it */
 177
 178     p = (char *) GlobalLock( handle );
 179     dprintf_task(stddeb, "Master DOS environment at %p\n", p);
 180     for (; *p; p += strlen(p) + 1) dprintf_task(stddeb, "    %s\n", p);
 181     dprintf_task( stddeb, "Progname: %s\n", p+3 );
 182
 183     return handle;
 184 }
 185
 186
 187 /***********************************************************************
 188  *           TASK_LinkTask
 189  */
 190 static void TASK_LinkTask( HTASK hTask )
 191 {
 192     HTASK *prevTask;
 193     TDB *pTask;
 194
 195     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 196     prevTask = &hFirstTask;
 197     while (*prevTask)
 198     {
 199         TDB *prevTaskPtr = (TDB *)GlobalLock( *prevTask );
 200         if (prevTaskPtr->priority >= pTask->priority) break;
 201         prevTask = &prevTaskPtr->hNext;
 202     }
 203     pTask->hNext = *prevTask;
 204     *prevTask = hTask;
 205     nTaskCount++;
 206 }
 207
 208
 209 /***********************************************************************
 210  *           TASK_UnlinkTask
 211  */
 212 static void TASK_UnlinkTask( HTASK hTask )
 213 {
 214     HTASK *prevTask;
 215     TDB *pTask;
 216
 217     prevTask = &hFirstTask;
 218     while (*prevTask && (*prevTask != hTask))
 219     {
 220         pTask = (TDB *)GlobalLock( *prevTask );
 221         prevTask = &pTask->hNext;
 222     }
 223     if (*prevTask)
 224     {
 225         pTask = (TDB *)GlobalLock( *prevTask );
 226         *prevTask = pTask->hNext;
 227         pTask->hNext = 0;
 228         nTaskCount--;
 229     }
 230 }
 231
 232
 233 /***********************************************************************
 234  *           TASK_CreateThunks
 235  *
 236  * Create a thunk free-list in segment 'handle', starting from offset 'offset'
 237  * and containing 'count' entries.
 238  */
 239 static void TASK_CreateThunks( HGLOBAL handle, WORD offset, WORD count )
 240 {
 241     int i;
 242     WORD free;
 243     THUNKS *pThunk;
 244
 245     pThunk = (THUNKS *)((BYTE *)GlobalLock( handle ) + offset);
 246     pThunk->next = 0;
 247     pThunk->magic = THUNK_MAGIC;
 248     pThunk->free = (int)&pThunk->thunks - (int)pThunk;
 249     free = pThunk->free;
 250     for (i = 0; i < count-1; i++)
 251     {
 252         free += 8;  /* Offset of next thunk */
 253         pThunk->thunks[4*i] = free;
 254     }
 255     pThunk->thunks[4*i] = 0;  /* Last thunk */
 256 }
 257
 258
 259 /***********************************************************************
 260  *           TASK_AllocThunk
 261  *
 262  * Allocate a thunk for MakeProcInstance().
 263  */
 264 #ifndef WINELIB32
 265 static SEGPTR TASK_AllocThunk( HTASK hTask )
 266 {
 267     TDB *pTask;
 268     THUNKS *pThunk;
 269     WORD sel, base;
 270
 271     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 272     sel = pTask->hCSAlias;
 273     pThunk = &pTask->thunks;
 274     base = (int)pThunk - (int)pTask;
 275     while (!pThunk->free)
 276     {
 277         sel = pThunk->next;
 278         if (!sel)  /* Allocate a new segment */
 279         {
 280             sel = GLOBAL_Alloc( GMEM_FIXED, sizeof(THUNKS) + (MIN_THUNKS-1)*8,
 281                                 pTask->hPDB, TRUE, FALSE, FALSE );
 282             if (!sel) return (SEGPTR)0;
 283             TASK_CreateThunks( sel, 0, MIN_THUNKS );
 284             pThunk->next = sel;
 285         }
 286         pThunk = (THUNKS *)GlobalLock( sel );
 287         base = 0;
 288     }
 289     base += pThunk->free;
 290     pThunk->free = *(WORD *)((BYTE *)pThunk + pThunk->free);
 291     return MAKELONG( base, sel );
 292 }
 293 #endif
 294
 295
 296 /***********************************************************************
 297  *           TASK_FreeThunk
 298  *
 299  * Free a MakeProcInstance() thunk.
 300  */
 301 #ifndef WINELIB32
 302 static BOOL TASK_FreeThunk( HTASK hTask, SEGPTR thunk )
 303 {
 304     TDB *pTask;
 305     THUNKS *pThunk;
 306     WORD sel, base;
 307
 308     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
 309     sel = pTask->hCSAlias;
 310     pThunk = &pTask->thunks;
 311     base = (int)pThunk - (int)pTask;
 312     while (sel && (sel != HIWORD(thunk)))
 313     {
 314         sel = pThunk->next;
 315         pThunk = (THUNKS *)GlobalLock( sel );
 316         base = 0;
 317     }
 318     if (!sel) return FALSE;
 319     *(WORD *)((BYTE *)pThunk + LOWORD(thunk) - base) = pThunk->free;
 320     pThunk->free = LOWORD(thunk) - base;
 321     return TRUE;
 322 }
 323 #endif
 324
 325
 326 /***********************************************************************
 327  *           TASK_CallToStart
 328  *
 329  * 32-bit entry point for a new task. This function is responsible for
 330  * setting up the registers and jumping to the 16-bit entry point.
 331  */
 332 #ifndef WINELIB
 333 static void TASK_CallToStart(void)
 334 {
 335     int cs_reg, ds_reg, ip_reg;
 336     TDB *pTask = (TDB *)GlobalLock( hCurrentTask );
 337     NE_MODULE *pModule = (NE_MODULE *)GlobalLock( pTask->hModule );
 338     SEGTABLEENTRY *pSegTable = NE_SEG_TABLE( pModule );
 339
 340     /* Registers at initialization must be:
 341      * ax   zero
 342      * bx   stack size in bytes
 343      * cx   heap size in bytes
 344      * si   previous app instance
 345      * di   current app instance
 346      * bp   zero
 347      * es   selector to the PSP
 348      * ds   dgroup of the application
 349      * ss   stack selector
 350      * sp   top of the stack
 351      */
 352
 353     cs_reg = pSegTable[pModule->cs - 1].selector;
 354     ip_reg = pModule->ip;
 355     ds_reg = pSegTable[pModule->dgroup - 1].selector;
 356
 357     IF1632_Saved16_ss = pTask->ss;
 358     IF1632_Saved16_sp = pTask->sp;
 359     dprintf_task( stddeb, "Starting main program: cs:ip=%04x:%04x ds=%04x ss:sp=%04x:%04x\n",
 360                  cs_reg, ip_reg, ds_reg,
 361                  IF1632_Saved16_ss, IF1632_Saved16_sp);
 362
 363     CallTo16_regs_( (FARPROC)(cs_reg << 16 | ip_reg), ds_reg,
 364                    pTask->hPDB /*es*/, 0 /*bp*/, 0 /*ax*/,
 365                    pModule->stack_size /*bx*/, pModule->heap_size /*cx*/,
 366                    0 /*dx*/, 0 /*si*/, ds_reg /*di*/ );
 367
 368     /* This should never return */
 369     fprintf( stderr, "TASK_CallToStart: Main program returned!\n" );
 370     TASK_KillCurrentTask( 1 );
 371 }
 372 #endif
 373
 374
 375 /***********************************************************************
 376  *           TASK_CreateTask
 377  */
 378 HTASK TASK_CreateTask( HMODULE hModule, HANDLE hInstance, HANDLE hPrevInstance,
 379                        HANDLE hEnvironment, char *cmdLine, WORD cmdShow )
 380 {
 381     HTASK hTask;
 382     TDB *pTask;
 383     HANDLE hParentEnv;
 384     NE_MODULE *pModule;
 385     SEGTABLEENTRY *pSegTable;
 386     LPSTR name;
 387     char filename[256];
 388 #ifndef WINELIB32
 389     char *stack16Top, *stack32Top;
 390     STACK16FRAME *frame16;
 391     STACK32FRAME *frame32;
 392     extern DWORD CALL16_RetAddr_word;
 393 #endif
 394
 395     if (!(pModule = (NE_MODULE *)GlobalLock( hModule ))) return 0;
 396     pSegTable = NE_SEG_TABLE( pModule );
 397
 398       /* Allocate the task structure */
 399
 400     hTask = GLOBAL_Alloc( GMEM_FIXED | GMEM_ZEROINIT, sizeof(TDB),
 401                           hModule, FALSE, FALSE, FALSE );
 402     if (!hTask) return 0;
 403     pTask = (TDB *)GlobalLock( hTask );
 404
 405       /* Allocate the new environment block */
 406
 407     if (!(hParentEnv = hEnvironment))
 408     {
 409         TDB *pParent = (TDB *)GlobalLock( hCurrentTask );
 410         hParentEnv = pParent ? pParent->pdb.environment : hDOSEnvironment;
 411     }
 412     /* FIXME: do we really need to make a copy also when */
 413     /*        we don't use the parent environment? */
 414     if (!(hEnvironment = GlobalAlloc( GMEM_FIXED, GlobalSize( hParentEnv ) )))
 415     {
 416         GlobalFree( hTask );
 417         return 0;
 418     }
 419     memcpy( GlobalLock( hEnvironment ), GlobalLock( hParentEnv ),
 420             GlobalSize( hParentEnv ) );
 421
 422       /* Get current directory */
 423
 424     GetModuleFileName( hModule, filename, sizeof(filename) );
 425     name = strrchr(filename, '\\');
 426     if (name) *(name+1) = 0;
 427
 428       /* Fill the task structure */
 429
 430     pTask->nEvents       = 1;  /* So the task can be started */
 431     pTask->hSelf         = hTask;
 432     pTask->flags         = 0;
 433     pTask->version       = pModule->expected_version;
 434     pTask->hInstance     = hInstance;
 435     pTask->hPrevInstance = hPrevInstance;
 436     pTask->hModule       = hModule;
 437     pTask->hParent       = hCurrentTask;
 438 #ifdef WINELIB
 439     pTask->curdrive      = 'C' - 'A' + 0x80;
 440     strcpy( pTask->curdir, "\\" );
 441 #else
 442     pTask->curdrive      = filename[0] - 'A' + 0x80;
 443     strcpy( pTask->curdir, filename+2 );
 444 #endif
 445     pTask->magic         = TDB_MAGIC;
 446     pTask->nCmdShow      = cmdShow;
 447
 448       /* Create the thunks block */
 449
 450     TASK_CreateThunks( hTask, (int)&pTask->thunks - (int)pTask, 7 );
 451
 452       /* Copy the module name */
 453
 454     name = MODULE_GetModuleName( hModule );
 455     strncpy( pTask->module_name, name, sizeof(pTask->module_name) );
 456
 457       /* Allocate a selector for the PDB */
 458
 459     pTask->hPDB = GLOBAL_CreateBlock( GMEM_FIXED, &pTask->pdb, sizeof(PDB),
 460                                       hModule, FALSE, FALSE, FALSE, NULL );
 461
 462       /* Fill the PDB */
 463
 464     pTask->pdb.int20 = 0x20cd;
 465 #ifndef WINELIB
 466     pTask->pdb.dispatcher[0] = 0x9a;  /* ljmp */
 467     *(DWORD *)&pTask->pdb.dispatcher[1] = MODULE_GetEntryPoint( GetModuleHandle("KERNEL"), 102 );  /* KERNEL.102 is DOS3Call() */
 468     pTask->pdb.savedint22 = INT_GetHandler( 0x22 );
 469     pTask->pdb.savedint23 = INT_GetHandler( 0x23 );
 470     pTask->pdb.savedint24 = INT_GetHandler( 0x24 );
 471     pTask->pdb.fileHandlesPtr = (SEGPTR)MAKELONG( 0x18,
 472                                               GlobalHandleToSel(pTask->hPDB) );
 473 #else
 474     pTask->pdb.fileHandlesPtr = pTask->pdb.fileHandles;
 475 #endif
 476     memset( pTask->pdb.fileHandles, 0xff, sizeof(pTask->pdb.fileHandles) );
 477     pTask->pdb.environment    = hEnvironment;
 478     pTask->pdb.nbFiles        = 20;
 479     lstrcpyn( pTask->pdb.cmdLine + 1, cmdLine, 127 );
 480     pTask->pdb.cmdLine[0] = strlen( pTask->pdb.cmdLine + 1 );
 481
 482       /* Get the compatibility flags */
 483
 484     pTask->compat_flags = GetProfileInt( name, "Compatibility", 0 );
 485
 486       /* Allocate a code segment alias for the TDB */
 487
 488     pTask->hCSAlias = GLOBAL_CreateBlock( GMEM_FIXED, (void *)pTask,
 489                                           sizeof(TDB), pTask->hPDB, TRUE,
 490                                           FALSE, FALSE, NULL );
 491
 492       /* Set the owner of the environment block */
 493
 494     FarSetOwner( pTask->pdb.environment, pTask->hPDB );
 495
 496       /* Default DTA overwrites command-line */
 497
 498     pTask->dta = MAKELONG( (int)&pTask->pdb.cmdLine - (int)&pTask->pdb,
 499                            pTask->hPDB );
 500
 501       /* Allocate the 32-bit stack */
 502
 503 #ifndef WINELIB
 504     pTask->hStack32 = GLOBAL_Alloc( GMEM_FIXED, STACK32_SIZE, pTask->hPDB,
 505                                     FALSE, FALSE, FALSE );
 506
 507       /* Create the 32-bit stack frame */
 508
 509     *(DWORD *)GlobalLock(pTask->hStack32) = 0xDEADBEEF;
 510     stack32Top = (char*)GlobalLock(pTask->hStack32) + STACK32_SIZE;
 511     frame32 = (STACK32FRAME *)stack32Top - 1;
 512     frame32->saved_esp = (DWORD)stack32Top;
 513     frame32->edi = 0;
 514     frame32->esi = 0;
 515     frame32->edx = 0;
 516     frame32->ecx = 0;
 517     frame32->ebx = 0;
 518     frame32->ebp = 0;
 519     frame32->retaddr = (DWORD)TASK_CallToStart;
 520     frame32->codeselector = WINE_CODE_SELECTOR;
 521     pTask->esp = (DWORD)frame32;
 522
 523       /* Create the 16-bit stack frame */
 524
 525     pTask->ss = hInstance;
 526     pTask->sp = ((pModule->sp != 0) ? pModule->sp :
 527                  pSegTable[pModule->ss-1].minsize + pModule->stack_size) & ~1;
 528     stack16Top = (char *)PTR_SEG_OFF_TO_LIN( pTask->ss, pTask->sp );
 529     frame16 = (STACK16FRAME *)stack16Top - 1;
 530     frame16->saved_ss = 0; /*pTask->ss;*/
 531     frame16->saved_sp = 0; /*pTask->sp;*/
 532     frame16->ds = frame16->es = pTask->hInstance;
 533     frame16->entry_point = 0;
 534     frame16->ordinal_number = 24;  /* WINPROCS.24 is TASK_Reschedule */
 535     frame16->dll_id = 24; /* WINPROCS */
 536     frame16->bp = 0;
 537     frame16->ip = LOWORD( CALL16_RetAddr_word );
 538     frame16->cs = HIWORD( CALL16_RetAddr_word );
 539     pTask->sp -= sizeof(STACK16FRAME);
 540
 541       /* If there's no 16-bit stack yet, use a part of the new task stack */
 542       /* This is only needed to have a stack to switch from on the first  */
 543       /* call to DirectedYield(). */
 544
 545     if (!IF1632_Saved16_ss)
 546     {
 547         IF1632_Saved16_ss = pTask->ss;
 548         IF1632_Saved16_sp = pTask->sp;
 549     }
 550
 551       /* Add a breakpoint at the start of the task */
 552
 553     if (Options.debug)
 554     {
 555         DBG_ADDR addr = { pSegTable[pModule->cs-1].selector, pModule->ip };
 556         fprintf( stderr, "Task '%s': ", name );
 557         DEBUG_AddBreakpoint( &addr );
 558     }
 559 #endif
 560
 561       /* Add the task to the linked list */
 562
 563     TASK_LinkTask( hTask );
 564
 565     dprintf_task( stddeb, "CreateTask: module='%s' cmdline='%s' task="NPFMT"\n",
 566                   name, cmdLine, hTask );
 567
 568     return hTask;
 569 }
 570
 571
 572 /***********************************************************************
 573  *           TASK_DeleteTask
 574  */
 575 static void TASK_DeleteTask( HTASK hTask )
 576 {
 577     TDB *pTask;
 578
 579     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 580
 581     /* Close all open files of this task */
 582
 583     FILE_CloseAllFiles( pTask->hPDB );
 584
 585       /* Free the task module */
 586
 587     FreeModule( pTask->hModule );
 588
 589       /* Free all memory used by this task (including the 32-bit stack, */
 590       /* the environment block and the thunk segments). */
 591
 592     GlobalFreeAll( pTask->hPDB );
 593
 594       /* Free message queue */
 595
 596     MSG_DeleteMsgQueue( pTask->hQueue );
 597
 598       /* Free the selector aliases */
 599
 600     GLOBAL_FreeBlock( pTask->hCSAlias );
 601     GLOBAL_FreeBlock( pTask->hPDB );
 602
 603       /* Free the task structure itself */
 604
 605     GlobalFree( hTask );
 606 }
 607
 608
 609 /***********************************************************************
 610  *           TASK_KillCurrentTask
 611  *
 612  * Kill the currently running task. As it's not possible to kill the
 613  * current task like this, it is simply marked for destruction, and will
 614  * be killed when either TASK_Reschedule or this function is called again
 615  * in the context of another task.
 616  */
 617 void TASK_KillCurrentTask( int exitCode )
 618 {
 619     if (hTaskToKill && (hTaskToKill != hCurrentTask))
 620     {
 621         /* If another task is already marked for destruction, */
 622         /* we call kill it now, as we are in another context. */
 623         TASK_DeleteTask( hTaskToKill );
 624     }
 625
 626     if (nTaskCount <= 1)
 627     {
 628         dprintf_task( stddeb, "Killing the last task, exiting\n" );
 629         exit(0);
 630     }
 631
 632     /* Remove the task from the list to be sure we never switch back to it */
 633     TASK_UnlinkTask( hCurrentTask );
 634
 635     hTaskToKill = hCurrentTask;
 636     hLockedTask = 0;
 637
 638     Yield();
 639     /* We should never return from this Yield() */
 640
 641     fprintf(stderr,"It's alive! Alive!!!\n");
 642     exit(1);
 643 }
 644
 645
 646 /***********************************************************************
 647  *           TASK_Reschedule
 648  *
 649  * This is where all the magic of task-switching happens!
 650  *
 651  * This function should only be called via the TASK_SCHEDULE() macro, to make
 652  * sure that all the context is saved correctly.
 653  */
 654 void TASK_Reschedule(void)
 655 {
 656     TDB *pOldTask = NULL, *pNewTask;
 657     HTASK hTask = 0;
 658
 659 #ifdef CONFIG_IPC
 660     dde_reschedule();
 661 #endif
 662       /* First check if there's a task to kill */
 663
 664     if (hTaskToKill && (hTaskToKill != hCurrentTask))
 665     {
 666         TASK_DeleteTask( hTaskToKill );
 667         hTaskToKill = 0;
 668     }
 669
 670       /* If current task is locked, simply return */
 671
 672     if (hLockedTask) return;
 673
 674       /* Find a task to yield to */
 675
 676     pOldTask = (TDB *)GlobalLock( hCurrentTask );
 677     if (pOldTask && pOldTask->hYieldTo)
 678     {
 679         /* If a task is stored in hYieldTo of the current task (put there */
 680         /* by DirectedYield), yield to it only if it has events pending.  */
 681         hTask = pOldTask->hYieldTo;
 682         if (!(pNewTask = (TDB *)GlobalLock( hTask )) || !pNewTask->nEvents)
 683             hTask = 0;
 684     }
 685
 686     if (!hTask)
 687     {
 688         hTask = hFirstTask;
 689         while (hTask)
 690         {
 691             pNewTask = (TDB *)GlobalLock( hTask );
 692             if (pNewTask->nEvents && (hTask != hCurrentTask)) break;
 693             hTask = pNewTask->hNext;
 694         }
 695     }
 696
 697      /* If there's a task to kill, switch to any other task, */
 698      /* even if it doesn't have events pending. */
 699
 700     if (!hTask && hTaskToKill) hTask = hFirstTask;
 701
 702     if (!hTask) return;  /* Do nothing */
 703
 704     pNewTask = (TDB *)GlobalLock( hTask );
 705     dprintf_task( stddeb, "Switching to task "NPFMT" (%.8s)\n",
 706                   hTask, pNewTask->module_name );
 707
 708       /* Save the stacks of the previous task (if any) */
 709
 710 #ifndef WINELIB /* FIXME: JBP: IF1632 not allowed in libwine.a */
 711     if (pOldTask)
 712     {
 713         pOldTask->ss  = IF1632_Saved16_ss;
 714         pOldTask->sp  = IF1632_Saved16_sp;
 715         pOldTask->esp = IF1632_Saved32_esp;
 716     }
 717     else IF1632_Original32_esp = IF1632_Saved32_esp;
 718 #endif
 719
 720      /* Make the task the last in the linked list (round-robin scheduling) */
 721
 722     pNewTask->priority++;
 723     TASK_UnlinkTask( hTask );
 724     TASK_LinkTask( hTask );
 725     pNewTask->priority--;
 726
 727       /* Switch to the new stack */
 728
 729     hCurrentTask = hTask;
 730 #ifndef WINELIB /* FIXME: JBP: IF1632 not allowed in libwine.a */
 731     IF1632_Saved16_ss   = pNewTask->ss;
 732     IF1632_Saved16_sp   = pNewTask->sp;
 733     IF1632_Saved32_esp  = pNewTask->esp;
 734     IF1632_Stack32_base = WIN16_GlobalLock( pNewTask->hStack32 );
 735 #endif
 736 }
 737
 738
 739 /***********************************************************************
 740  *           InitTask  (KERNEL.91)
 741  */
 742 #ifdef WINELIB
 743 void InitTask(void)
 744 #else
 745 void InitTask( struct sigcontext_struct context )
 746 #endif
 747 {
 748     static int firstTask = 1;
 749     TDB *pTask;
 750     NE_MODULE *pModule;
 751     SEGTABLEENTRY *pSegTable;
 752     INSTANCEDATA *pinstance;
 753     LONG stacklow, stackhi;
 754
 755 #ifndef WINELIB
 756     EAX_reg(&context) = 0;
 757 #endif
 758     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return;
 759     if (!(pModule = (NE_MODULE *)GlobalLock( pTask->hModule ))) return;
 760
 761     if (firstTask)
 762     {
 763         extern BOOL WIDGETS_Init(void);
 764         extern BOOL WIN_CreateDesktopWindow(void);
 765
 766         /* Perform global initialisations that need a task context */
 767
 768           /* Initialize built-in window classes */
 769         if (!WIDGETS_Init()) return;
 770
 771           /* Create desktop window */
 772         if (!WIN_CreateDesktopWindow()) return;
 773
 774         firstTask = 0;
 775     }
 776
 777 #ifndef WINELIB
 778     NE_InitializeDLLs( pTask->hModule );
 779
 780     /* Registers on return are:
 781      * ax     1 if OK, 0 on error
 782      * cx     stack limit in bytes
 783      * dx     cmdShow parameter
 784      * si     instance handle of the previous instance
 785      * di     instance handle of the new task
 786      * es:bx  pointer to command-line inside PSP
 787      */
 788     EAX_reg(&context) = 1;
 789     EBX_reg(&context) = 0x81;
 790     ECX_reg(&context) = pModule->stack_size;
 791     EDX_reg(&context) = pTask->nCmdShow;
 792     ESI_reg(&context) = (DWORD)pTask->hPrevInstance;
 793     EDI_reg(&context) = (DWORD)pTask->hInstance;
 794     ES_reg (&context) = (WORD)pTask->hPDB;
 795 #endif
 796
 797     /* Initialize the local heap */
 798     if ( pModule->heap_size )
 799     {
 800         LocalInit( pTask->hInstance, 0, pModule->heap_size );
 801     }
 802
 803
 804     /* Initialize the INSTANCEDATA structure */
 805     pSegTable = NE_SEG_TABLE( pModule );
 806     stacklow = pSegTable[pModule->ss - 1].minsize;
 807     stackhi  = stacklow + pModule->stack_size;
 808     if (stackhi > 0xffff) stackhi = 0xffff;
 809     pinstance = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN(CURRENT_DS, 0);
 810     pinstance->stackbottom = stackhi; /* yup, that's right. Confused me too. */
 811     pinstance->stacktop    = stacklow;
 812 #ifndef WINELIB
 813     pinstance->stackmin    = IF1632_Saved16_sp;
 814 #endif
 815 }
 816
 817
 818 /***********************************************************************
 819  *           WaitEvent  (KERNEL.30)
 820  */
 821 BOOL WaitEvent( HTASK hTask )
 822 {
 823     TDB *pTask;
 824
 825     if (!hTask) hTask = hCurrentTask;
 826     pTask = (TDB *)GlobalLock( hTask );
 827     if (pTask->nEvents > 0)
 828     {
 829         pTask->nEvents--;
 830         return FALSE;
 831     }
 832     TASK_SCHEDULE();
 833     /* When we get back here, we have an event (or the task is the only one) */
 834     if (pTask->nEvents > 0) pTask->nEvents--;
 835     return TRUE;
 836 }
 837
 838
 839 /***********************************************************************
 840  *           PostEvent  (KERNEL.31)
 841  */
 842 void PostEvent( HTASK hTask )
 843 {
 844     TDB *pTask;
 845
 846     if (!hTask) hTask = hCurrentTask;
 847     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 848     pTask->nEvents++;
 849 }
 850
 851
 852 /***********************************************************************
 853  *           SetPriority  (KERNEL.32)
 854  */
 855 void SetPriority( HTASK hTask, int delta )
 856 {
 857     TDB *pTask;
 858     int newpriority;
 859
 860     if (!hTask) hTask = hCurrentTask;
 861     if (!(pTask = (TDB *)GlobalLock( hTask ))) return;
 862     newpriority = pTask->priority + delta;
 863     if (newpriority < -32) newpriority = -32;
 864     else if (newpriority > 15) newpriority = 15;
 865
 866     pTask->priority = newpriority + 1;
 867     TASK_UnlinkTask( hTask );
 868     TASK_LinkTask( hTask );
 869     pTask->priority--;
 870 }
 871
 872
 873 /***********************************************************************
 874  *           LockCurrentTask  (KERNEL.33)
 875  */
 876 HTASK LockCurrentTask( BOOL bLock )
 877 {
 878     if (bLock) hLockedTask = hCurrentTask;
 879     else hLockedTask = 0;
 880     return hLockedTask;
 881 }
 882
 883
 884 /***********************************************************************
 885  *           IsTaskLocked  (KERNEL.122)
 886  */
 887 HTASK IsTaskLocked(void)
 888 {
 889     return hLockedTask;
 890 }
 891
 892
 893 /***********************************************************************
 894  *           OldYield  (KERNEL.117)
 895  */
 896 void OldYield(void)
 897 {
 898     TDB *pCurTask;
 899
 900     pCurTask = (TDB *)GlobalLock( hCurrentTask );
 901     if (pCurTask) pCurTask->nEvents++;  /* Make sure we get back here */
 902     TASK_SCHEDULE();
 903     if (pCurTask) pCurTask->nEvents--;
 904 }
 905
 906
 907 /***********************************************************************
 908  *           DirectedYield  (KERNEL.150)
 909  */
 910 void DirectedYield( HTASK hTask )
 911 {
 912     TDB *pCurTask;
 913
 914     if ((pCurTask = (TDB *)GlobalLock( hCurrentTask )) != NULL)
 915         pCurTask->hYieldTo = hTask;
 916
 917     OldYield();
 918 }
 919
 920
 921 /***********************************************************************
 922  *           Yield  (KERNEL.29)
 923  */
 924 void Yield(void)
 925 {
 926     DirectedYield( 0 );
 927 }
 928
 929
 930 /***********************************************************************
 931  *           MakeProcInstance  (KERNEL.51)
 932  */
 933 FARPROC MakeProcInstance( FARPROC func, HANDLE hInstance )
 934 {
 935 #ifdef WINELIB32
 936     return func; /* func can be called directly in Win32 */
 937 #else
 938     BYTE *thunk;
 939     SEGPTR thunkaddr;
 940
 941     thunkaddr = TASK_AllocThunk( hCurrentTask );
 942     if (!thunkaddr) return (FARPROC)0;
 943     thunk = PTR_SEG_TO_LIN( thunkaddr );
 944
 945     dprintf_task( stddeb, "MakeProcInstance("SPFMT","NPFMT"): got thunk "SPFMT"\n",
 946                   (SEGPTR)func, hInstance, (SEGPTR)thunkaddr );
 947
 948     *thunk++ = 0xb8;    /* movw instance, %ax */
 949     *thunk++ = (BYTE)(hInstance & 0xff);
 950     *thunk++ = (BYTE)(hInstance >> 8);
 951     *thunk++ = 0xea;    /* ljmp func */
 952     *(DWORD *)thunk = (DWORD)func;
 953     return (FARPROC)thunkaddr;
 954 #endif
 955 }
 956
 957
 958 /***********************************************************************
 959  *           FreeProcInstance  (KERNEL.52)
 960  */
 961 void FreeProcInstance( FARPROC func )
 962 {
 963 #ifndef WINELIB32
 964     dprintf_task( stddeb, "FreeProcInstance("SPFMT")\n", (SEGPTR)func );
 965     TASK_FreeThunk( hCurrentTask, (SEGPTR)func );
 966 #endif
 967 }
 968
 969
 970 /**********************************************************************
 971  *          GetCodeHandle    (KERNEL.93)
 972  */
 973 HANDLE GetCodeHandle( FARPROC proc )
 974 {
 975     HANDLE handle;
 976     BYTE *thunk = (BYTE *)PTR_SEG_TO_LIN( proc );
 977
 978     /* Return the code segment containing 'proc'. */
 979     /* Not sure if this is really correct (shouldn't matter that much). */
 980
 981     /* Check if it is really a thunk */
 982     if ((thunk[0] == 0xb8) && (thunk[3] == 0xea))
 983         handle = GlobalHandle( thunk[6] + (thunk[7] << 8) );
 984     else
 985         handle = GlobalHandle( HIWORD(proc) );
 986
 987     return handle;
 988 }
 989
 990
 991 /***********************************************************************
 992  *           SetTaskQueue  (KERNEL.34)
 993  */
 994 HGLOBAL SetTaskQueue( HANDLE hTask, HGLOBAL hQueue )
 995 {
 996     HGLOBAL hPrev;
 997     TDB *pTask;
 998
 999     if (!hTask) hTask = hCurrentTask;
1000     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
1001     hPrev = pTask->hQueue;
1002     pTask->hQueue = hQueue;
1003     return hPrev;
1004 }
1005
1006
1007 /***********************************************************************
1008  *           GetTaskQueue  (KERNEL.35)
1009  */
1010 HGLOBAL GetTaskQueue( HANDLE hTask )
1011 {
1012     TDB *pTask;
1013
1014     if (!hTask) hTask = hCurrentTask;
1015     if (!(pTask = (TDB *)GlobalLock( hTask ))) return 0;
1016     return pTask->hQueue;
1017 }
1018
1019
1020 /***********************************************************************
1021  *           GetTaskQueueDS  (KERNEL.118)
1022  */
1023 #ifndef WINELIB
1024 void GetTaskQueueDS( struct sigcontext_struct context )
1025 {
1026     DS_reg(&context) = GlobalHandleToSel( GetTaskQueue(0) );
1027 }
1028 #endif  /* WINELIB */
1029
1030
1031 /***********************************************************************
1032  *           GetTaskQueueES  (KERNEL.119)
1033  */
1034 #ifndef WINELIB
1035 void GetTaskQueueES( struct sigcontext_struct context )
1036 {
1037     ES_reg(&context) = GlobalHandleToSel( GetTaskQueue(0) );
1038 }
1039 #endif  /* WINELIB */
1040
1041
1042 /***********************************************************************
1043  *           GetCurrentTask   (KERNEL.36)
1044  */
1045 HTASK GetCurrentTask(void)
1046 {
1047       /* Undocumented: first task is returned in high word */
1048 #ifdef WINELIB32
1049     return hCurrentTask;
1050 #else
1051     return MAKELONG( hCurrentTask, hFirstTask );
1052 #endif
1053 }
1054
1055
1056 /***********************************************************************
1057  *           GetCurrentPDB   (KERNEL.37)
1058  */
1059 HANDLE GetCurrentPDB(void)
1060 {
1061     TDB *pTask;
1062
1063     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
1064     return pTask->hPDB;
1065 }
1066
1067
1068 /***********************************************************************
1069  *           GetInstanceData   (KERNEL.54)
1070  */
1071 int GetInstanceData( HANDLE instance, WORD buffer, int len )
1072 {
1073     char *ptr = (char *)GlobalLock( instance );
1074     if (!ptr || !len) return 0;
1075     if ((int)buffer + len >= 0x10000) len = 0x10000 - buffer;
1076     memcpy( ptr + buffer, (char *)GlobalLock( CURRENT_DS ) + buffer, len );
1077     return len;
1078 }
1079
1080
1081 /***********************************************************************
1082  *           SetErrorMode   (KERNEL.107)
1083  */
1084 UINT SetErrorMode( UINT mode )
1085 {
1086     TDB *pTask;
1087     UINT oldMode;
1088
1089     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
1090     oldMode = pTask->error_mode;
1091     pTask->error_mode = mode;
1092     return oldMode;
1093 }
1094
1095
1096 /***********************************************************************
1097  *           GetDOSEnvironment   (KERNEL.131)
1098  */
1099 SEGPTR GetDOSEnvironment(void)
1100 {
1101     TDB *pTask;
1102
1103     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
1104     return (SEGPTR)WIN16_GlobalLock( pTask->pdb.environment );
1105 }
1106
1107
1108 /***********************************************************************
1109  *           GetNumTasks   (KERNEL.152)
1110  */
1111 WORD GetNumTasks(void)
1112 {
1113     return nTaskCount;
1114 }
1115
1116
1117 /***********************************************************************
1118  *           GetTaskDS   (KERNEL.155)
1119  */
1120 HINSTANCE GetTaskDS(void)
1121 {
1122     TDB *pTask;
1123
1124     if (!(pTask = (TDB *)GlobalLock( hCurrentTask ))) return 0;
1125     return pTask->hInstance;
1126 }
1127
1128
1129 /***********************************************************************
1130  *           IsTask   (KERNEL.320)
1131  */
1132 BOOL IsTask( HTASK hTask )
1133 {
1134     TDB *pTask;
1135
1136     if (!(pTask = (TDB *)GlobalLock( hTask ))) return FALSE;
1137     if (GlobalSize( hTask ) < sizeof(TDB)) return FALSE;
1138     return (pTask->magic == TDB_MAGIC);
1139 }
1140
1141
1142 /***********************************************************************
1143  *           GetExePtr   (KERNEL.133)
1144  */
1145 HMODULE GetExePtr( HANDLE handle )
1146 {
1147     char *ptr;
1148     HTASK hTask;
1149     HANDLE owner;
1150
1151       /* Check for module handle */
1152
1153     if (!(ptr = GlobalLock( handle ))) return 0;
1154     if (((NE_MODULE *)ptr)->magic == NE_SIGNATURE) return handle;
1155         /* Fake modules describing PE modules have a PE signature */
1156     if (((NE_MODULE *)ptr)->magic == PE_SIGNATURE) return handle;
1157
1158       /* Check the owner for module handle */
1159
1160 #ifndef WINELIB
1161     owner = FarGetOwner( handle );
1162 #else
1163     owner = NULL;
1164 #endif
1165     if (!(ptr = GlobalLock( owner ))) return 0;
1166     if (((NE_MODULE *)ptr)->magic == NE_SIGNATURE) return owner;
1167     if (((NE_MODULE *)ptr)->magic == PE_SIGNATURE) return owner;
1168
1169       /* Search for this handle and its owner inside all tasks */
1170
1171     hTask = hFirstTask;
1172     while (hTask)
1173     {
1174         TDB *pTask = (TDB *)GlobalLock( hTask );
1175         if ((hTask == handle) ||
1176             (pTask->hInstance == handle) ||
1177             (pTask->hQueue == handle) ||
1178             (pTask->hPDB == handle)) return pTask->hModule;
1179         if ((hTask == owner) ||
1180             (pTask->hInstance == owner) ||
1181             (pTask->hQueue == owner) ||
1182             (pTask->hPDB == owner)) return pTask->hModule;
1183         hTask = pTask->hNext;
1184     }
1185     return 0;
1186 }
1187
1188
1189 /***********************************************************************
1190  *           TaskFirst   (TOOLHELP.63)
1191  */
1192 BOOL TaskFirst( TASKENTRY *lpte )
1193 {
1194     lpte->hNext = hFirstTask;
1195     return TaskNext( lpte );
1196 }
1197
1198
1199 /***********************************************************************
1200  *           TaskNext   (TOOLHELP.64)
1201  */
1202 BOOL TaskNext( TASKENTRY *lpte )
1203 {
1204     TDB *pTask;
1205     INSTANCEDATA *pInstData;
1206
1207     dprintf_toolhelp( stddeb, "TaskNext(%p): task="NPFMT"\n", lpte, lpte->hNext );
1208     if (!lpte->hNext) return FALSE;
1209     pTask = (TDB *)GlobalLock( lpte->hNext );
1210     if (!pTask || pTask->magic != TDB_MAGIC) return FALSE;
1211     pInstData = (INSTANCEDATA *)PTR_SEG_OFF_TO_LIN( pTask->hInstance, 0 );
1212     lpte->hTask         = lpte->hNext;
1213     lpte->hTaskParent   = pTask->hParent;
1214     lpte->hInst         = pTask->hInstance;
1215     lpte->hModule       = pTask->hModule;
1216     lpte->wSS           = pTask->ss;
1217     lpte->wSP           = pTask->sp;
1218     lpte->wStackTop     = pInstData->stacktop;
1219     lpte->wStackMinimum = pInstData->stackmin;
1220     lpte->wStackBottom  = pInstData->stackbottom;
1221     lpte->wcEvents      = pTask->nEvents;
1222     lpte->hQueue        = pTask->hQueue;
1223     strncpy( lpte->szModule, pTask->module_name, 8 );
1224     lpte->szModule[8]   = '\0';
1225     lpte->wPSPOffset    = 0x100;  /*??*/
1226     lpte->hNext         = pTask->hNext;
1227     return TRUE;
1228 }
1229
1230
1231 /***********************************************************************
1232  *           TaskFindHandle   (TOOLHELP.65)
1233  */
1234 BOOL TaskFindHandle( TASKENTRY *lpte, HTASK hTask )
1235 {
1236     lpte->hNext = hTask;
1237     return TaskNext( lpte );
1238 }