memory/selector.c

   1 /*
   2  * Selector manipulation functions
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "config.h"
  22 #include "wine/port.h"
  23
  24 #include <string.h>
  25
  26 #include "winerror.h"
  27 #include "wine/winbase16.h"
  28 #include "miscemu.h"
  29 #include "selectors.h"
  30 #include "stackframe.h"
  31 #include "wine/server.h"
  32 #include "wine/debug.h"
  33 #include "toolhelp.h"
  34
  35 WINE_DEFAULT_DEBUG_CHANNEL(selector);
  36
  37 #define LDT_SIZE 8192
  38
  39 /* get the number of selectors needed to cover up to the selector limit */
  40 inline static WORD get_sel_count( WORD sel )
  41 {
  42     return (wine_ldt_copy.limit[sel >> __AHSHIFT] >> 16) + 1;
  43 }
  44
  45 static const LDT_ENTRY null_entry;  /* all-zeros, used to clear LDT entries */
  46
  47 /***********************************************************************
  48  *           SELECTOR_AllocArray
  49  *
  50  * Allocate a selector array without setting the LDT entries
  51  */
  52 static WORD SELECTOR_AllocArray( WORD count )
  53 {
  54     WORD i, sel, size = 0;
  55
  56     if (!count) return 0;
  57     for (i = FIRST_LDT_ENTRY_TO_ALLOC; i < LDT_SIZE; i++)
  58     {
  59         if (wine_ldt_copy.flags[i] & WINE_LDT_FLAGS_ALLOCATED) size = 0;
  60         else if (++size >= count) break;
  61     }
  62     if (i == LDT_SIZE) return 0;
  63     sel = i - size + 1;
  64
  65     /* mark selectors as allocated */
  66     for (i = 0; i < count; i++) wine_ldt_copy.flags[sel + i] |= WINE_LDT_FLAGS_ALLOCATED;
  67
  68     return (sel << __AHSHIFT) | 7;
  69 }
  70
  71
  72 /***********************************************************************
  73  *           AllocSelectorArray   (KERNEL.206)
  74  */
  75 WORD WINAPI AllocSelectorArray16( WORD count )
  76 {
  77     WORD i, sel = SELECTOR_AllocArray( count );
  78
  79     if (sel)
  80     {
  81         LDT_ENTRY entry;
  82         wine_ldt_set_base( &entry, 0 );
  83         wine_ldt_set_limit( &entry, 1 ); /* avoid 0 base and limit */
  84         wine_ldt_set_flags( &entry, WINE_LDT_FLAGS_DATA );
  85         for (i = 0; i < count; i++) wine_ldt_set_entry( sel + (i << __AHSHIFT), &entry );
  86     }
  87     return sel;
  88 }
  89
  90
  91 /***********************************************************************
  92  *           AllocSelector   (KERNEL.175)
  93  */
  94 WORD WINAPI AllocSelector16( WORD sel )
  95 {
  96     WORD newsel, count, i;
  97
  98     count = sel ? get_sel_count(sel) : 1;
  99     newsel = SELECTOR_AllocArray( count );
 100     TRACE("(%04x): returning %04x\n", sel, newsel );
 101     if (!newsel) return 0;
 102     if (!sel) return newsel;  /* nothing to copy */
 103     for (i = 0; i < count; i++)
 104     {
 105         LDT_ENTRY entry;
 106         wine_ldt_get_entry( sel + (i << __AHSHIFT), &entry );
 107         wine_ldt_set_entry( newsel + (i << __AHSHIFT), &entry );
 108     }
 109     return newsel;
 110 }
 111
 112
 113 /***********************************************************************
 114  *           FreeSelector   (KERNEL.176)
 115  */
 116 WORD WINAPI FreeSelector16( WORD sel )
 117 {
 118     if (IS_SELECTOR_FREE(sel)) return sel;  /* error */
 119
 120 #ifdef __i386__
 121     /* Check if we are freeing current %fs or %gs selector */
 122     if (!((wine_get_fs() ^ sel) & ~7))
 123     {
 124         WARN("Freeing %%fs selector (%04x), not good.\n", wine_get_fs() );
 125         wine_set_fs( 0 );
 126     }
 127     if (!((wine_get_gs() ^ sel) & ~7)) wine_set_gs( 0 );
 128 #endif  /* __i386__ */
 129
 130     wine_ldt_set_entry( sel, &null_entry );
 131     wine_ldt_copy.flags[sel >> __AHSHIFT] &= ~WINE_LDT_FLAGS_ALLOCATED;
 132     return 0;
 133 }
 134
 135
 136 /***********************************************************************
 137  *           SELECTOR_FreeFs
 138  *
 139  * Free the current %fs selector.
 140  */
 141 void SELECTOR_FreeFs(void)
 142 {
 143     WORD fs = wine_get_fs();
 144     if (fs)
 145     {
 146         wine_ldt_copy.flags[fs >> __AHSHIFT] &= ~WINE_LDT_FLAGS_ALLOCATED;
 147         wine_set_fs(0);
 148         wine_ldt_set_entry( fs, &null_entry );
 149     }
 150 }
 151
 152
 153 /***********************************************************************
 154  *           SELECTOR_SetEntries
 155  *
 156  * Set the LDT entries for an array of selectors.
 157  */
 158 static void SELECTOR_SetEntries( WORD sel, const void *base, DWORD size, unsigned char flags )
 159 {
 160     LDT_ENTRY entry;
 161     WORD i, count;
 162
 163     wine_ldt_set_base( &entry, base );
 164     /* Make sure base and limit are not 0 together if the size is not 0 */
 165     wine_ldt_set_limit( &entry, (!base && size == 1) ? 1 : size - 1 );
 166     wine_ldt_set_flags( &entry, flags );
 167     count = (size + 0xffff) / 0x10000;
 168     for (i = 0; i < count; i++)
 169     {
 170         wine_ldt_set_entry( sel + (i << __AHSHIFT), &entry );
 171         wine_ldt_set_base( &entry, wine_ldt_get_base(&entry) + 0x10000 );
 172         /* yep, Windows sets limit like that, not 64K sel units */
 173         wine_ldt_set_limit( &entry, wine_ldt_get_limit(&entry) - 0x10000 );
 174     }
 175 }
 176
 177
 178 /***********************************************************************
 179  *           SELECTOR_AllocBlock
 180  *
 181  * Allocate selectors for a block of linear memory.
 182  */
 183 WORD SELECTOR_AllocBlock( const void *base, DWORD size, unsigned char flags )
 184 {
 185     WORD sel, count;
 186
 187     if (!size) return 0;
 188     count = (size + 0xffff) / 0x10000;
 189     sel = SELECTOR_AllocArray( count );
 190     if (sel) SELECTOR_SetEntries( sel, base, size, flags );
 191     return sel;
 192 }
 193
 194
 195 /***********************************************************************
 196  *           SELECTOR_FreeBlock
 197  *
 198  * Free a block of selectors.
 199  */
 200 void SELECTOR_FreeBlock( WORD sel )
 201 {
 202     WORD i, count = get_sel_count( sel );
 203
 204     TRACE("(%04x,%d)\n", sel, count );
 205     for (i = 0; i < count; i++) FreeSelector16( sel + (i << __AHSHIFT) );
 206 }
 207
 208
 209 /***********************************************************************
 210  *           SELECTOR_ReallocBlock
 211  *
 212  * Change the size of a block of selectors.
 213  */
 214 WORD SELECTOR_ReallocBlock( WORD sel, const void *base, DWORD size )
 215 {
 216     LDT_ENTRY entry;
 217     WORD i, oldcount, newcount;
 218
 219     if (!size) size = 1;
 220     oldcount = get_sel_count( sel );
 221     newcount = (size + 0xffff) >> 16;
 222     wine_ldt_get_entry( sel, &entry );
 223
 224     if (oldcount < newcount)  /* We need to add selectors */
 225     {
 226         WORD index = sel >> __AHSHIFT;
 227           /* Check if the next selectors are free */
 228         if (index + newcount > LDT_SIZE) i = oldcount;
 229         else
 230             for (i = oldcount; i < newcount; i++)
 231                 if (wine_ldt_copy.flags[index+i] & WINE_LDT_FLAGS_ALLOCATED) break;
 232
 233         if (i < newcount)  /* they are not free */
 234         {
 235             SELECTOR_FreeBlock( sel );
 236             sel = SELECTOR_AllocArray( newcount );
 237         }
 238         else  /* mark the selectors as allocated */
 239         {
 240             for (i = oldcount; i < newcount; i++)
 241                 wine_ldt_copy.flags[index+i] |= WINE_LDT_FLAGS_ALLOCATED;
 242         }
 243     }
 244     else if (oldcount > newcount) /* We need to remove selectors */
 245     {
 246         SELECTOR_FreeBlock( sel + (newcount << __AHSHIFT) );
 247     }
 248     if (sel) SELECTOR_SetEntries( sel, base, size, wine_ldt_get_flags(&entry) );
 249     return sel;
 250 }
 251
 252
 253 /***********************************************************************
 254  *           PrestoChangoSelector   (KERNEL.177)
 255  */
 256 WORD WINAPI PrestoChangoSelector16( WORD selSrc, WORD selDst )
 257 {
 258     LDT_ENTRY entry;
 259     wine_ldt_get_entry( selSrc, &entry );
 260     /* toggle the executable bit */
 261     entry.HighWord.Bits.Type ^= (WINE_LDT_FLAGS_CODE ^ WINE_LDT_FLAGS_DATA);
 262     wine_ldt_set_entry( selDst, &entry );
 263     return selDst;
 264 }
 265
 266
 267 /***********************************************************************
 268  *           AllocCStoDSAlias   (KERNEL.170)
 269  *           AllocAlias         (KERNEL.172)
 270  */
 271 WORD WINAPI AllocCStoDSAlias16( WORD sel )
 272 {
 273     WORD newsel;
 274     LDT_ENTRY entry;
 275
 276     newsel = SELECTOR_AllocArray( 1 );
 277     TRACE("(%04x): returning %04x\n",
 278                       sel, newsel );
 279     if (!newsel) return 0;
 280     wine_ldt_get_entry( sel, &entry );
 281     entry.HighWord.Bits.Type = WINE_LDT_FLAGS_DATA;
 282     wine_ldt_set_entry( newsel, &entry );
 283     return newsel;
 284 }
 285
 286
 287 /***********************************************************************
 288  *           AllocDStoCSAlias   (KERNEL.171)
 289  */
 290 WORD WINAPI AllocDStoCSAlias16( WORD sel )
 291 {
 292     WORD newsel;
 293     LDT_ENTRY entry;
 294
 295     newsel = SELECTOR_AllocArray( 1 );
 296     TRACE("(%04x): returning %04x\n",
 297                       sel, newsel );
 298     if (!newsel) return 0;
 299     wine_ldt_get_entry( sel, &entry );
 300     entry.HighWord.Bits.Type = WINE_LDT_FLAGS_CODE;
 301     wine_ldt_set_entry( newsel, &entry );
 302     return newsel;
 303 }
 304
 305
 306 /***********************************************************************
 307  *           LongPtrAdd   (KERNEL.180)
 308  */
 309 void WINAPI LongPtrAdd16( DWORD ptr, DWORD add )
 310 {
 311     LDT_ENTRY entry;
 312     wine_ldt_get_entry( SELECTOROF(ptr), &entry );
 313     wine_ldt_set_base( &entry, (char *)wine_ldt_get_base(&entry) + add );
 314     wine_ldt_set_entry( SELECTOROF(ptr), &entry );
 315 }
 316
 317
 318 /***********************************************************************
 319  *           GetSelectorBase   (KERNEL.186)
 320  */
 321 DWORD WINAPI WIN16_GetSelectorBase( WORD sel )
 322 {
 323     /*
 324      * Note: For Win32s processes, the whole linear address space is
 325      *       shifted by 0x10000 relative to the OS linear address space.
 326      *       See the comment in msdos/vxd.c.
 327      */
 328
 329     DWORD base = GetSelectorBase( sel );
 330     return W32S_WINE2APP( base );
 331 }
 332 DWORD WINAPI GetSelectorBase( WORD sel )
 333 {
 334     void *base = wine_ldt_copy.base[sel >> __AHSHIFT];
 335
 336     /* if base points into DOSMEM, assume we have to
 337      * return pointer into physical lower 1MB */
 338
 339     return DOSMEM_MapLinearToDos( base );
 340 }
 341
 342
 343 /***********************************************************************
 344  *           SetSelectorBase   (KERNEL.187)
 345  */
 346 DWORD WINAPI WIN16_SetSelectorBase( WORD sel, DWORD base )
 347 {
 348     /*
 349      * Note: For Win32s processes, the whole linear address space is
 350      *       shifted by 0x10000 relative to the OS linear address space.
 351      *       See the comment in msdos/vxd.c.
 352      */
 353
 354     SetSelectorBase( sel, W32S_APP2WINE( base ) );
 355     return sel;
 356 }
 357 WORD WINAPI SetSelectorBase( WORD sel, DWORD base )
 358 {
 359     LDT_ENTRY entry;
 360     wine_ldt_get_entry( sel, &entry );
 361     wine_ldt_set_base( &entry, DOSMEM_MapDosToLinear(base) );
 362     wine_ldt_set_entry( sel, &entry );
 363     return sel;
 364 }
 365
 366
 367 /***********************************************************************
 368  *           GetSelectorLimit   (KERNEL.188)
 369  */
 370 DWORD WINAPI GetSelectorLimit16( WORD sel )
 371 {
 372     return wine_ldt_copy.limit[sel >> __AHSHIFT];
 373 }
 374
 375
 376 /***********************************************************************
 377  *           SetSelectorLimit   (KERNEL.189)
 378  */
 379 WORD WINAPI SetSelectorLimit16( WORD sel, DWORD limit )
 380 {
 381     LDT_ENTRY entry;
 382     wine_ldt_get_entry( sel, &entry );
 383     wine_ldt_set_limit( &entry, limit );
 384     wine_ldt_set_entry( sel, &entry );
 385     return sel;
 386 }
 387
 388
 389 /***********************************************************************
 390  *           SelectorAccessRights   (KERNEL.196)
 391  */
 392 WORD WINAPI SelectorAccessRights16( WORD sel, WORD op, WORD val )
 393 {
 394     LDT_ENTRY entry;
 395     wine_ldt_get_entry( sel, &entry );
 396
 397     if (op == 0)  /* get */
 398     {
 399         return entry.HighWord.Bytes.Flags1 | ((entry.HighWord.Bytes.Flags2 << 8) & 0xf0);
 400     }
 401     else  /* set */
 402     {
 403         entry.HighWord.Bytes.Flags1 = LOBYTE(val) | 0xf0;
 404         entry.HighWord.Bytes.Flags2 = (entry.HighWord.Bytes.Flags2 & 0x0f) | (HIBYTE(val) & 0xf0);
 405         wine_ldt_set_entry( sel, &entry );
 406         return 0;
 407     }
 408 }
 409
 410
 411 /***********************************************************************
 412  *           IsBadCodePtr   (KERNEL.336)
 413  */
 414 BOOL16 WINAPI IsBadCodePtr16( SEGPTR lpfn )
 415 {
 416     WORD sel;
 417     LDT_ENTRY entry;
 418
 419     sel = SELECTOROF(lpfn);
 420     if (!sel) return TRUE;
 421     if (IS_SELECTOR_FREE(sel)) return TRUE;
 422     wine_ldt_get_entry( sel, &entry );
 423     /* check for code segment, ignoring conforming, read-only and accessed bits */
 424     if ((entry.HighWord.Bits.Type ^ WINE_LDT_FLAGS_CODE) & 0x18) return TRUE;
 425     if (OFFSETOF(lpfn) > wine_ldt_get_limit(&entry)) return TRUE;
 426     return FALSE;
 427 }
 428
 429
 430 /***********************************************************************
 431  *           IsBadStringPtr   (KERNEL.337)
 432  */
 433 BOOL16 WINAPI IsBadStringPtr16( SEGPTR ptr, UINT16 size )
 434 {
 435     WORD sel;
 436     LDT_ENTRY entry;
 437
 438     sel = SELECTOROF(ptr);
 439     if (!sel) return TRUE;
 440     if (IS_SELECTOR_FREE(sel)) return TRUE;
 441     wine_ldt_get_entry( sel, &entry );
 442     /* check for data or readable code segment */
 443     if (!(entry.HighWord.Bits.Type & 0x10)) return TRUE;  /* system descriptor */
 444     if ((entry.HighWord.Bits.Type & 0x0a) == 0x08) return TRUE;  /* non-readable code segment */
 445     if (strlen(MapSL(ptr)) < size) size = strlen(MapSL(ptr)) + 1;
 446     if (size && (OFFSETOF(ptr) + size - 1 > wine_ldt_get_limit(&entry))) return TRUE;
 447     return FALSE;
 448 }
 449
 450
 451 /***********************************************************************
 452  *           IsBadHugeReadPtr   (KERNEL.346)
 453  */
 454 BOOL16 WINAPI IsBadHugeReadPtr16( SEGPTR ptr, DWORD size )
 455 {
 456     WORD sel;
 457     LDT_ENTRY entry;
 458
 459     sel = SELECTOROF(ptr);
 460     if (!sel) return TRUE;
 461     if (IS_SELECTOR_FREE(sel)) return TRUE;
 462     wine_ldt_get_entry( sel, &entry );
 463     /* check for data or readable code segment */
 464     if (!(entry.HighWord.Bits.Type & 0x10)) return TRUE;  /* system descriptor */
 465     if ((entry.HighWord.Bits.Type & 0x0a) == 0x08) return TRUE;  /* non-readable code segment */
 466     if (size && (OFFSETOF(ptr) + size - 1 > wine_ldt_get_limit( &entry ))) return TRUE;
 467     return FALSE;
 468 }
 469
 470
 471 /***********************************************************************
 472  *           IsBadHugeWritePtr   (KERNEL.347)
 473  */
 474 BOOL16 WINAPI IsBadHugeWritePtr16( SEGPTR ptr, DWORD size )
 475 {
 476     WORD sel;
 477     LDT_ENTRY entry;
 478
 479     sel = SELECTOROF(ptr);
 480     if (!sel) return TRUE;
 481     if (IS_SELECTOR_FREE(sel)) return TRUE;
 482     wine_ldt_get_entry( sel, &entry );
 483     /* check for writeable data segment, ignoring expand-down and accessed flags */
 484     if ((entry.HighWord.Bits.Type ^ WINE_LDT_FLAGS_DATA) & ~5) return TRUE;
 485     if (size && (OFFSETOF(ptr) + size - 1 > wine_ldt_get_limit( &entry ))) return TRUE;
 486     return FALSE;
 487 }
 488
 489 /***********************************************************************
 490  *           IsBadReadPtr   (KERNEL.334)
 491  */
 492 BOOL16 WINAPI IsBadReadPtr16( SEGPTR ptr, UINT16 size )
 493 {
 494     return IsBadHugeReadPtr16( ptr, size );
 495 }
 496
 497
 498 /***********************************************************************
 499  *           IsBadWritePtr   (KERNEL.335)
 500  */
 501 BOOL16 WINAPI IsBadWritePtr16( SEGPTR ptr, UINT16 size )
 502 {
 503     return IsBadHugeWritePtr16( ptr, size );
 504 }
 505
 506
 507 /***********************************************************************
 508  *           IsBadFlatReadWritePtr   (KERNEL.627)
 509  */
 510 BOOL16 WINAPI IsBadFlatReadWritePtr16( SEGPTR ptr, DWORD size, BOOL16 bWrite )
 511 {
 512     return bWrite? IsBadHugeWritePtr16( ptr, size )
 513                  : IsBadHugeReadPtr16( ptr, size );
 514 }
 515
 516
 517 /***********************************************************************
 518  *           MemoryRead   (TOOLHELP.78)
 519  */
 520 DWORD WINAPI MemoryRead16( WORD sel, DWORD offset, void *buffer, DWORD count )
 521 {
 522     WORD index = sel >> __AHSHIFT;
 523
 524     if (!(wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED)) return 0;
 525     if (offset > wine_ldt_copy.limit[index]) return 0;
 526     if (offset + count > wine_ldt_copy.limit[index] + 1)
 527         count = wine_ldt_copy.limit[index] + 1 - offset;
 528     memcpy( buffer, (char *)wine_ldt_copy.base[index] + offset, count );
 529     return count;
 530 }
 531
 532
 533 /***********************************************************************
 534  *           MemoryWrite   (TOOLHELP.79)
 535  */
 536 DWORD WINAPI MemoryWrite16( WORD sel, DWORD offset, void *buffer, DWORD count )
 537 {
 538     WORD index = sel >> __AHSHIFT;
 539
 540     if (!(wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED)) return 0;
 541     if (offset > wine_ldt_copy.limit[index]) return 0;
 542     if (offset + count > wine_ldt_copy.limit[index] + 1)
 543         count = wine_ldt_copy.limit[index] + 1 - offset;
 544     memcpy( (char *)wine_ldt_copy.base[index] + offset, buffer, count );
 545     return count;
 546 }
 547
 548 /************************************* Win95 pointer mapping functions *
 549  *
 550  */
 551
 552 struct mapls_entry
 553 {
 554     struct mapls_entry *next;
 555     void               *addr;   /* linear address */
 556     int                 count;  /* ref count */
 557     WORD                sel;    /* selector */
 558 };
 559
 560 static struct mapls_entry *first_entry;
 561
 562
 563 /***********************************************************************
 564  *           MapLS   (KERNEL32.@)
 565  *           MapLS   (KERNEL.358)
 566  *
 567  * Maps linear pointer to segmented.
 568  */
 569 SEGPTR WINAPI MapLS( LPCVOID ptr )
 570 {
 571     struct mapls_entry *entry, *free = NULL;
 572     void *base;
 573     SEGPTR ret = 0;
 574
 575     if (!HIWORD(ptr)) return (SEGPTR)ptr;
 576
 577     base = (char *)ptr - ((unsigned int)ptr & 0x7fff);
 578     HeapLock( GetProcessHeap() );
 579     for (entry = first_entry; entry; entry = entry->next)
 580     {
 581         if (entry->addr == base) break;
 582         if (!entry->count) free = entry;
 583     }
 584
 585     if (!entry)
 586     {
 587         if (!free)  /* no free entry found, create a new one */
 588         {
 589             if (!(free = HeapAlloc( GetProcessHeap(), 0, sizeof(*free) ))) goto done;
 590             if (!(free->sel = SELECTOR_AllocBlock( base, 0x10000, WINE_LDT_FLAGS_DATA )))
 591             {
 592                 HeapFree( GetProcessHeap(), 0, free );
 593                 goto done;
 594             }
 595             free->count = 0;
 596             free->next = first_entry;
 597             first_entry = free;
 598         }
 599         SetSelectorBase( free->sel, (DWORD)base );
 600         free->addr = base;
 601         entry = free;
 602     }
 603     entry->count++;
 604     ret = MAKESEGPTR( entry->sel, (char *)ptr - (char *)entry->addr );
 605  done:
 606     HeapUnlock( GetProcessHeap() );
 607     return ret;
 608 }
 609
 610 /***********************************************************************
 611  *           UnMapLS   (KERNEL32.@)
 612  *           UnMapLS   (KERNEL.359)
 613  *
 614  * Free mapped selector.
 615  */
 616 void WINAPI UnMapLS( SEGPTR sptr )
 617 {
 618     struct mapls_entry *entry;
 619     WORD sel = SELECTOROF(sptr);
 620
 621     if (sel)
 622     {
 623         HeapLock( GetProcessHeap() );
 624         for (entry = first_entry; entry; entry = entry->next) if (entry->sel == sel) break;
 625         if (entry && entry->count > 0) entry->count--;
 626         HeapUnlock( GetProcessHeap() );
 627     }
 628 }
 629
 630 /***********************************************************************
 631  *           MapSL   (KERNEL32.@)
 632  *           MapSL   (KERNEL.357)
 633  *
 634  * Maps fixed segmented pointer to linear.
 635  */
 636 LPVOID WINAPI MapSL( SEGPTR sptr )
 637 {
 638     return (char *)wine_ldt_copy.base[SELECTOROF(sptr) >> __AHSHIFT] + OFFSETOF(sptr);
 639 }
 640
 641 /***********************************************************************
 642  *           MapSLFix   (KERNEL32.@)
 643  *
 644  * FIXME: MapSLFix and UnMapSLFixArray should probably prevent
 645  * unexpected linear address change when GlobalCompact() shuffles
 646  * moveable blocks.
 647  */
 648
 649 LPVOID WINAPI MapSLFix( SEGPTR sptr )
 650 {
 651     return MapSL(sptr);
 652 }
 653
 654 /***********************************************************************
 655  *           UnMapSLFixArray   (KERNEL32.@)
 656  */
 657
 658 void WINAPI UnMapSLFixArray( SEGPTR sptr[], INT length, CONTEXT86 *context )
 659 {
 660     /* Must not change EAX, hence defined as 'register' function */
 661 }
 662
 663 /***********************************************************************
 664  *           GetThreadSelectorEntry   (KERNEL32.@)
 665  */
 666 BOOL WINAPI GetThreadSelectorEntry( HANDLE hthread, DWORD sel, LPLDT_ENTRY ldtent)
 667 {
 668 #ifdef __i386__
 669     BOOL ret;
 670
 671     if (!(sel & 4))  /* GDT selector */
 672     {
 673         sel &= ~3;  /* ignore RPL */
 674         if (!sel)  /* null selector */
 675         {
 676             memset( ldtent, 0, sizeof(*ldtent) );
 677             return TRUE;
 678         }
 679         ldtent->BaseLow                   = 0;
 680         ldtent->HighWord.Bits.BaseMid     = 0;
 681         ldtent->HighWord.Bits.BaseHi      = 0;
 682         ldtent->LimitLow                  = 0xffff;
 683         ldtent->HighWord.Bits.LimitHi     = 0xf;
 684         ldtent->HighWord.Bits.Dpl         = 3;
 685         ldtent->HighWord.Bits.Sys         = 0;
 686         ldtent->HighWord.Bits.Pres        = 1;
 687         ldtent->HighWord.Bits.Granularity = 1;
 688         ldtent->HighWord.Bits.Default_Big = 1;
 689         ldtent->HighWord.Bits.Type        = 0x12;
 690         /* it has to be one of the system GDT selectors */
 691         if (sel == (wine_get_ds() & ~3)) return TRUE;
 692         if (sel == (wine_get_ss() & ~3)) return TRUE;
 693         if (sel == (wine_get_cs() & ~3))
 694         {
 695             ldtent->HighWord.Bits.Type |= 8;  /* code segment */
 696             return TRUE;
 697         }
 698         SetLastError( ERROR_NOACCESS );
 699         return FALSE;
 700     }
 701
 702     SERVER_START_REQ( get_selector_entry )
 703     {
 704         req->handle = hthread;
 705         req->entry = sel >> __AHSHIFT;
 706         if ((ret = !wine_server_call_err( req )))
 707         {
 708             if (!(reply->flags & WINE_LDT_FLAGS_ALLOCATED))
 709             {
 710                 SetLastError( ERROR_MR_MID_NOT_FOUND );  /* sic */
 711                 ret = FALSE;
 712             }
 713             else
 714             {
 715                 wine_ldt_set_base( ldtent, (void *)reply->base );
 716                 wine_ldt_set_limit( ldtent, reply->limit );
 717                 wine_ldt_set_flags( ldtent, reply->flags );
 718             }
 719         }
 720     }
 721     SERVER_END_REQ;
 722     return ret;
 723 #else
 724     SetLastError( ERROR_CALL_NOT_IMPLEMENTED );
 725     return FALSE;
 726 #endif
 727 }
 728
 729
 730 /**********************************************************************
 731  *              SMapLS*         (KERNEL32)
 732  * These functions map linear pointers at [EBP+xxx] to segmented pointers
 733  * and return them.
 734  * Win95 uses some kind of alias structs, which it stores in [EBP+x] to
 735  * unravel them at SUnMapLS. We just store the segmented pointer there.
 736  */
 737 static void
 738 x_SMapLS_IP_EBP_x(CONTEXT86 *context,int argoff) {
 739     DWORD       val,ptr;
 740
 741     val =*(DWORD*)(context->Ebp + argoff);
 742     if (val<0x10000) {
 743         ptr=val;
 744         *(DWORD*)(context->Ebp + argoff) = 0;
 745     } else {
 746         ptr = MapLS((LPVOID)val);
 747         *(DWORD*)(context->Ebp + argoff) = ptr;
 748     }
 749     context->Eax = ptr;
 750 }
 751
 752 /***********************************************************************
 753  *              SMapLS_IP_EBP_8 (KERNEL32.@)
 754  */
 755 void WINAPI SMapLS_IP_EBP_8 (CONTEXT86 *context) {x_SMapLS_IP_EBP_x(context, 8);}
 756
 757 /***********************************************************************
 758  *              SMapLS_IP_EBP_12 (KERNEL32.@)
 759  */
 760 void WINAPI SMapLS_IP_EBP_12(CONTEXT86 *context) {x_SMapLS_IP_EBP_x(context,12);}
 761
 762 /***********************************************************************
 763  *              SMapLS_IP_EBP_16 (KERNEL32.@)
 764  */
 765 void WINAPI SMapLS_IP_EBP_16(CONTEXT86 *context) {x_SMapLS_IP_EBP_x(context,16);}
 766
 767 /***********************************************************************
 768  *              SMapLS_IP_EBP_20 (KERNEL32.@)
 769  */
 770 void WINAPI SMapLS_IP_EBP_20(CONTEXT86 *context) {x_SMapLS_IP_EBP_x(context,20);}
 771
 772 /***********************************************************************
 773  *              SMapLS_IP_EBP_24 (KERNEL32.@)
 774  */
 775 void WINAPI SMapLS_IP_EBP_24(CONTEXT86 *context) {x_SMapLS_IP_EBP_x(context,24);}
 776
 777 /***********************************************************************
 778  *              SMapLS_IP_EBP_28 (KERNEL32.@)
 779  */
 780 void WINAPI SMapLS_IP_EBP_28(CONTEXT86 *context) {x_SMapLS_IP_EBP_x(context,28);}
 781
 782 /***********************************************************************
 783  *              SMapLS_IP_EBP_32 (KERNEL32.@)
 784  */
 785 void WINAPI SMapLS_IP_EBP_32(CONTEXT86 *context) {x_SMapLS_IP_EBP_x(context,32);}
 786
 787 /***********************************************************************
 788  *              SMapLS_IP_EBP_36 (KERNEL32.@)
 789  */
 790 void WINAPI SMapLS_IP_EBP_36(CONTEXT86 *context) {x_SMapLS_IP_EBP_x(context,36);}
 791
 792 /***********************************************************************
 793  *              SMapLS_IP_EBP_40 (KERNEL32.@)
 794  */
 795 void WINAPI SMapLS_IP_EBP_40(CONTEXT86 *context) {x_SMapLS_IP_EBP_x(context,40);}
 796
 797 /***********************************************************************
 798  *              SMapLS (KERNEL32.@)
 799  */
 800 void WINAPI SMapLS( CONTEXT86 *context )
 801 {
 802     if (HIWORD(context->Eax))
 803     {
 804         context->Eax = MapLS( (LPVOID)context->Eax );
 805         context->Edx = context->Eax;
 806     } else {
 807         context->Edx = 0;
 808     }
 809 }
 810
 811 /***********************************************************************
 812  *              SUnMapLS (KERNEL32.@)
 813  */
 814
 815 void WINAPI SUnMapLS( CONTEXT86 *context )
 816 {
 817     if (HIWORD(context->Eax)) UnMapLS( (SEGPTR)context->Eax );
 818 }
 819
 820 inline static void x_SUnMapLS_IP_EBP_x(CONTEXT86 *context,int argoff)
 821 {
 822     SEGPTR *ptr = (SEGPTR *)(context->Ebp + argoff);
 823     if (*ptr)
 824     {
 825         UnMapLS( *ptr );
 826         *ptr = 0;
 827     }
 828 }
 829
 830 /***********************************************************************
 831  *              SUnMapLS_IP_EBP_8 (KERNEL32.@)
 832  */
 833 void WINAPI SUnMapLS_IP_EBP_8 (CONTEXT86 *context) { x_SUnMapLS_IP_EBP_x(context, 8); }
 834
 835 /***********************************************************************
 836  *              SUnMapLS_IP_EBP_12 (KERNEL32.@)
 837  */
 838 void WINAPI SUnMapLS_IP_EBP_12(CONTEXT86 *context) { x_SUnMapLS_IP_EBP_x(context,12); }
 839
 840 /***********************************************************************
 841  *              SUnMapLS_IP_EBP_16 (KERNEL32.@)
 842  */
 843 void WINAPI SUnMapLS_IP_EBP_16(CONTEXT86 *context) { x_SUnMapLS_IP_EBP_x(context,16); }
 844
 845 /***********************************************************************
 846  *              SUnMapLS_IP_EBP_20 (KERNEL32.@)
 847  */
 848 void WINAPI SUnMapLS_IP_EBP_20(CONTEXT86 *context) { x_SUnMapLS_IP_EBP_x(context,20); }
 849
 850 /***********************************************************************
 851  *              SUnMapLS_IP_EBP_24 (KERNEL32.@)
 852  */
 853 void WINAPI SUnMapLS_IP_EBP_24(CONTEXT86 *context) { x_SUnMapLS_IP_EBP_x(context,24); }
 854
 855 /***********************************************************************
 856  *              SUnMapLS_IP_EBP_28 (KERNEL32.@)
 857  */
 858 void WINAPI SUnMapLS_IP_EBP_28(CONTEXT86 *context) { x_SUnMapLS_IP_EBP_x(context,28); }
 859
 860 /***********************************************************************
 861  *              SUnMapLS_IP_EBP_32 (KERNEL32.@)
 862  */
 863 void WINAPI SUnMapLS_IP_EBP_32(CONTEXT86 *context) { x_SUnMapLS_IP_EBP_x(context,32); }
 864
 865 /***********************************************************************
 866  *              SUnMapLS_IP_EBP_36 (KERNEL32.@)
 867  */
 868 void WINAPI SUnMapLS_IP_EBP_36(CONTEXT86 *context) { x_SUnMapLS_IP_EBP_x(context,36); }
 869
 870 /***********************************************************************
 871  *              SUnMapLS_IP_EBP_40 (KERNEL32.@)
 872  */
 873 void WINAPI SUnMapLS_IP_EBP_40(CONTEXT86 *context) { x_SUnMapLS_IP_EBP_x(context,40); }
 874
 875 /**********************************************************************
 876  *              AllocMappedBuffer       (KERNEL32.38)
 877  *
 878  * This is a undocumented KERNEL32 function that
 879  * SMapLS's a GlobalAlloc'ed buffer.
 880  *
 881  * Input:   EDI register: size of buffer to allocate
 882  * Output:  EDI register: pointer to buffer
 883  *
 884  * Note: The buffer is preceded by 8 bytes:
 885  *        ...
 886  *       edi+0   buffer
 887  *       edi-4   SEGPTR to buffer
 888  *       edi-8   some magic Win95 needs for SUnMapLS
 889  *               (we use it for the memory handle)
 890  *
 891  *       The SEGPTR is used by the caller!
 892  */
 893
 894 void WINAPI AllocMappedBuffer( CONTEXT86 *context )
 895 {
 896     HGLOBAL handle = GlobalAlloc(0, context->Edi + 8);
 897     DWORD *buffer = (DWORD *)GlobalLock(handle);
 898     SEGPTR ptr = 0;
 899
 900     if (buffer)
 901         if (!(ptr = MapLS(buffer + 2)))
 902         {
 903             GlobalUnlock(handle);
 904             GlobalFree(handle);
 905         }
 906
 907     if (!ptr)
 908         context->Eax = context->Edi = 0;
 909     else
 910     {
 911         buffer[0] = handle;
 912         buffer[1] = ptr;
 913
 914         context->Eax = (DWORD) ptr;
 915         context->Edi = (DWORD)(buffer + 2);
 916     }
 917 }
 918
 919 /**********************************************************************
 920  *              FreeMappedBuffer        (KERNEL32.39)
 921  *
 922  * Free a buffer allocated by AllocMappedBuffer
 923  *
 924  * Input: EDI register: pointer to buffer
 925  */
 926
 927 void WINAPI FreeMappedBuffer( CONTEXT86 *context )
 928 {
 929     if (context->Edi)
 930     {
 931         DWORD *buffer = (DWORD *)context->Edi - 2;
 932
 933         UnMapLS(buffer[1]);
 934
 935         GlobalUnlock(buffer[0]);
 936         GlobalFree(buffer[0]);
 937     }
 938 }