memory/selector.c

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