libs/wine/ldt.c

   1 /*
   2  * LDT manipulation functions
   3  *
   4  * Copyright 1993 Robert J. Amstadt
   5  * Copyright 1995 Alexandre Julliard
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include "config.h"
  23 #include "wine/port.h"
  24
  25 #include <assert.h>
  26 #include <stdlib.h>
  27 #include <stdarg.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <errno.h>
  31
  32 #include "windef.h"
  33 #include "winbase.h"
  34 #define WINE_EXPORT_LDT_COPY
  35 #include "wine/library.h"
  36
  37 #ifdef __i386__
  38
  39 #ifdef linux
  40
  41 #ifdef HAVE_SYS_SYSCALL_H
  42 # include <sys/syscall.h>
  43 #endif
  44
  45 struct modify_ldt_s
  46 {
  47     unsigned int  entry_number;
  48     unsigned long base_addr;
  49     unsigned int  limit;
  50     unsigned int  seg_32bit : 1;
  51     unsigned int  contents : 2;
  52     unsigned int  read_exec_only : 1;
  53     unsigned int  limit_in_pages : 1;
  54     unsigned int  seg_not_present : 1;
  55     unsigned int  useable : 1;
  56     unsigned int  garbage : 25;
  57 };
  58
  59 static inline void fill_modify_ldt_struct( struct modify_ldt_s *ptr, const LDT_ENTRY *entry )
  60 {
  61     ptr->base_addr       = (unsigned long)wine_ldt_get_base(entry);
  62     ptr->limit           = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
  63     ptr->seg_32bit       = entry->HighWord.Bits.Default_Big;
  64     ptr->contents        = (entry->HighWord.Bits.Type >> 2) & 3;
  65     ptr->read_exec_only  = !(entry->HighWord.Bits.Type & 2);
  66     ptr->limit_in_pages  = entry->HighWord.Bits.Granularity;
  67     ptr->seg_not_present = !entry->HighWord.Bits.Pres;
  68     ptr->useable         = entry->HighWord.Bits.Sys;
  69     ptr->garbage         = 0;
  70 }
  71
  72 static inline int modify_ldt( int func, struct modify_ldt_s *ptr, unsigned long count )
  73 {
  74     int res;
  75     __asm__ __volatile__( "pushl %%ebx\n\t"
  76                           "movl %2,%%ebx\n\t"
  77                           "int $0x80\n\t"
  78                           "popl %%ebx"
  79                           : "=a" (res)
  80                           : "0" (SYS_modify_ldt),
  81                             "r" (func),
  82                             "c" (ptr),
  83                             "d" (count) );
  84     if (res >= 0) return res;
  85     errno = -res;
  86     return -1;
  87 }
  88
  89 static inline int set_thread_area( struct modify_ldt_s *ptr )
  90 {
  91     int res;
  92     __asm__ __volatile__( "pushl %%ebx\n\t"
  93                           "movl %2,%%ebx\n\t"
  94                           "int $0x80\n\t"
  95                           "popl %%ebx"
  96                           : "=a" (res)
  97                           : "0" (243) /* SYS_set_thread_area */, "q" (ptr) );
  98     if (res >= 0) return res;
  99     errno = -res;
 100     return -1;
 101 }
 102
 103 #endif  /* linux */
 104
 105 #if defined(__svr4__) || defined(_SCO_DS)
 106 #include <sys/sysi86.h>
 107 #ifndef __sun__
 108 #include <sys/seg.h>
 109 #endif
 110 #endif
 111
 112 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
 113 #include <machine/segments.h>
 114
 115 extern int i386_get_ldt(int, union descriptor *, int);
 116 extern int i386_set_ldt(int, union descriptor *, int);
 117 #endif  /* __NetBSD__ || __FreeBSD__ || __OpenBSD__ */
 118
 119 #ifdef __APPLE__
 120
 121 static inline int thread_set_user_ldt( const void *addr, unsigned int size, unsigned int flags )
 122 {
 123     int ret;
 124     __asm__ __volatile__ ("pushl %4\n\t"
 125                           "pushl %3\n\t"
 126                           "pushl %2\n\t"
 127                           "pushl $0\n\t"
 128                           "lcall $0x3b,$0\n\t"
 129                           "leal  16(%%esp),%%esp"
 130                           : "=a" (ret)
 131                           : "0" (4 /*thread_set_user_ldt*/), "r" (addr), "r" (size), "r" (flags) );
 132     return ret;
 133 }
 134
 135 #endif  /* __APPLE__ */
 136
 137 #endif  /* __i386__ */
 138
 139 /* local copy of the LDT */
 140 #ifdef __APPLE__
 141 struct __wine_ldt_copy wine_ldt_copy = { { 0, 0, 0 } };
 142 #else
 143 struct __wine_ldt_copy wine_ldt_copy;
 144 #endif
 145
 146 static const LDT_ENTRY null_entry;  /* all-zeros, used to clear LDT entries */
 147
 148 #define LDT_FIRST_ENTRY 512
 149 #define LDT_SIZE 8192
 150
 151 /* empty function for default locks */
 152 static void nop(void) { }
 153
 154 static void (*lock_ldt)(void) = nop;
 155 static void (*unlock_ldt)(void) = nop;
 156
 157
 158 static inline int is_gdt_sel( unsigned short sel ) { return !(sel & 4); }
 159
 160 /***********************************************************************
 161  *           wine_ldt_init_locking
 162  *
 163  * Set the LDT locking/unlocking functions.
 164  */
 165 void wine_ldt_init_locking( void (*lock_func)(void), void (*unlock_func)(void) )
 166 {
 167     lock_ldt = lock_func;
 168     unlock_ldt = unlock_func;
 169 }
 170
 171
 172 /***********************************************************************
 173  *           wine_ldt_get_entry
 174  *
 175  * Retrieve an LDT entry. Return a null entry if selector is not allocated.
 176  */
 177 void wine_ldt_get_entry( unsigned short sel, LDT_ENTRY *entry )
 178 {
 179     int index = sel >> 3;
 180
 181     if (is_gdt_sel(sel))
 182     {
 183         *entry = null_entry;
 184         return;
 185     }
 186     lock_ldt();
 187     if (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED)
 188     {
 189         wine_ldt_set_base(  entry, wine_ldt_copy.base[index] );
 190         wine_ldt_set_limit( entry, wine_ldt_copy.limit[index] );
 191         wine_ldt_set_flags( entry, wine_ldt_copy.flags[index] );
 192     }
 193     else *entry = null_entry;
 194     unlock_ldt();
 195 }
 196
 197
 198 /***********************************************************************
 199  *           internal_set_entry
 200  *
 201  * Set an LDT entry, without locking. For internal use only.
 202  */
 203 static int internal_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 204 {
 205     int ret = 0, index = sel >> 3;
 206
 207     if (index < LDT_FIRST_ENTRY) return 0;  /* cannot modify reserved entries */
 208
 209 #ifdef __i386__
 210
 211 #ifdef linux
 212     {
 213         struct modify_ldt_s ldt_info;
 214
 215         ldt_info.entry_number = index;
 216         fill_modify_ldt_struct( &ldt_info, entry );
 217         if ((ret = modify_ldt(0x11, &ldt_info, sizeof(ldt_info))) < 0)
 218             perror( "modify_ldt" );
 219     }
 220 #elif defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
 221     {
 222         LDT_ENTRY entry_copy = *entry;
 223         /* The kernel will only let us set LDTs with user priority level */
 224         if (entry_copy.HighWord.Bits.Pres
 225             && entry_copy.HighWord.Bits.Dpl != 3)
 226                 entry_copy.HighWord.Bits.Dpl = 3;
 227         ret = i386_set_ldt(index, (union descriptor *)&entry_copy, 1);
 228         if (ret < 0)
 229         {
 230             perror("i386_set_ldt");
 231             fprintf( stderr, "Did you reconfigure the kernel with \"options USER_LDT\"?\n" );
 232             exit(1);
 233         }
 234     }
 235 #elif defined(__svr4__) || defined(_SCO_DS)
 236     {
 237         struct ssd ldt_mod;
 238         ldt_mod.sel  = sel;
 239         ldt_mod.bo   = (unsigned long)wine_ldt_get_base(entry);
 240         ldt_mod.ls   = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
 241         ldt_mod.acc1 = entry->HighWord.Bytes.Flags1;
 242         ldt_mod.acc2 = entry->HighWord.Bytes.Flags2 >> 4;
 243         if ((ret = sysi86(SI86DSCR, &ldt_mod)) == -1) perror("sysi86");
 244     }
 245 #else
 246     fprintf( stderr, "No LDT support on this platform\n" );
 247     exit(1);
 248 #endif
 249
 250 #endif  /* __i386__ */
 251
 252     if (ret >= 0)
 253     {
 254         wine_ldt_copy.base[index]  = wine_ldt_get_base(entry);
 255         wine_ldt_copy.limit[index] = wine_ldt_get_limit(entry);
 256         wine_ldt_copy.flags[index] = (entry->HighWord.Bits.Type |
 257                                  (entry->HighWord.Bits.Default_Big ? WINE_LDT_FLAGS_32BIT : 0) |
 258                                  (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED));
 259     }
 260     return ret;
 261 }
 262
 263
 264 /***********************************************************************
 265  *           wine_ldt_set_entry
 266  *
 267  * Set an LDT entry.
 268  */
 269 int wine_ldt_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 270 {
 271     int ret;
 272
 273     lock_ldt();
 274     ret = internal_set_entry( sel, entry );
 275     unlock_ldt();
 276     return ret;
 277 }
 278
 279
 280 /***********************************************************************
 281  *           wine_ldt_is_system
 282  *
 283  * Check if the selector is a system selector (i.e. not managed by Wine).
 284  */
 285 int wine_ldt_is_system( unsigned short sel )
 286 {
 287     return is_gdt_sel(sel) || ((sel >> 3) < LDT_FIRST_ENTRY);
 288 }
 289
 290
 291 /***********************************************************************
 292  *           wine_ldt_get_ptr
 293  *
 294  * Convert a segment:offset pair to a linear pointer.
 295  * Note: we don't lock the LDT since this has to be fast.
 296  */
 297 void *wine_ldt_get_ptr( unsigned short sel, unsigned long offset )
 298 {
 299     int index;
 300
 301     if (is_gdt_sel(sel))  /* GDT selector */
 302         return (void *)offset;
 303     if ((index = (sel >> 3)) < LDT_FIRST_ENTRY)  /* system selector */
 304         return (void *)offset;
 305     if (!(wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_32BIT)) offset &= 0xffff;
 306     return (char *)wine_ldt_copy.base[index] + offset;
 307 }
 308
 309
 310 /***********************************************************************
 311  *           wine_ldt_alloc_entries
 312  *
 313  * Allocate a number of consecutive ldt entries, without setting the LDT contents.
 314  * Return a selector for the first entry.
 315  */
 316 unsigned short wine_ldt_alloc_entries( int count )
 317 {
 318     int i, index, size = 0;
 319
 320     if (count <= 0) return 0;
 321     lock_ldt();
 322     for (i = LDT_FIRST_ENTRY; i < LDT_SIZE; i++)
 323     {
 324         if (wine_ldt_copy.flags[i] & WINE_LDT_FLAGS_ALLOCATED) size = 0;
 325         else if (++size >= count)  /* found a large enough block */
 326         {
 327             index = i - size + 1;
 328
 329             /* mark selectors as allocated */
 330             for (i = 0; i < count; i++) wine_ldt_copy.flags[index + i] |= WINE_LDT_FLAGS_ALLOCATED;
 331             unlock_ldt();
 332             return (index << 3) | 7;
 333         }
 334     }
 335     unlock_ldt();
 336     return 0;
 337 }
 338
 339
 340 /***********************************************************************
 341  *           wine_ldt_realloc_entries
 342  *
 343  * Reallocate a number of consecutive ldt entries, without changing the LDT contents.
 344  * Return a selector for the first entry.
 345  */
 346 unsigned short wine_ldt_realloc_entries( unsigned short sel, int oldcount, int newcount )
 347 {
 348     int i;
 349
 350     if (oldcount < newcount)  /* we need to add selectors */
 351     {
 352         int index = sel >> 3;
 353
 354         lock_ldt();
 355         /* check if the next selectors are free */
 356         if (index + newcount > LDT_SIZE) i = oldcount;
 357         else
 358             for (i = oldcount; i < newcount; i++)
 359                 if (wine_ldt_copy.flags[index+i] & WINE_LDT_FLAGS_ALLOCATED) break;
 360
 361         if (i < newcount)  /* they are not free */
 362         {
 363             wine_ldt_free_entries( sel, oldcount );
 364             sel = wine_ldt_alloc_entries( newcount );
 365         }
 366         else  /* mark the selectors as allocated */
 367         {
 368             for (i = oldcount; i < newcount; i++)
 369                 wine_ldt_copy.flags[index+i] |= WINE_LDT_FLAGS_ALLOCATED;
 370         }
 371         unlock_ldt();
 372     }
 373     else if (oldcount > newcount) /* we need to remove selectors */
 374     {
 375         wine_ldt_free_entries( sel + (newcount << 3), newcount - oldcount );
 376     }
 377     return sel;
 378 }
 379
 380
 381 /***********************************************************************
 382  *           wine_ldt_free_entries
 383  *
 384  * Free a number of consecutive ldt entries and clear their contents.
 385  */
 386 void wine_ldt_free_entries( unsigned short sel, int count )
 387 {
 388     int index;
 389
 390     lock_ldt();
 391     for (index = sel >> 3; count > 0; count--, index++)
 392     {
 393         internal_set_entry( sel, &null_entry );
 394         wine_ldt_copy.flags[index] = 0;
 395     }
 396     unlock_ldt();
 397 }
 398
 399
 400 #ifdef __i386__
 401
 402 static int global_fs_sel = -1;  /* global selector for %fs shared among all threads */
 403
 404 /***********************************************************************
 405  *           wine_ldt_alloc_fs
 406  *
 407  * Allocate an LDT entry for a %fs selector, reusing a global
 408  * GDT selector if possible. Return the selector value.
 409  */
 410 unsigned short wine_ldt_alloc_fs(void)
 411 {
 412     if (global_fs_sel == -1)
 413     {
 414 #ifdef __linux__
 415         struct modify_ldt_s ldt_info;
 416         int ret;
 417
 418         ldt_info.entry_number = -1;
 419         fill_modify_ldt_struct( &ldt_info, &null_entry );
 420         if ((ret = set_thread_area( &ldt_info ) < 0))
 421         {
 422             global_fs_sel = 0;  /* don't try it again */
 423             if (errno != ENOSYS) perror( "set_thread_area" );
 424         }
 425         else global_fs_sel = (ldt_info.entry_number << 3) | 3;
 426 #elif defined(__APPLE__)
 427         int ret = thread_set_user_ldt( NULL, 0, 0 );
 428         if (ret != -1) global_fs_sel = ret;
 429         else global_fs_sel = 0;
 430 #endif  /* __APPLE__ */
 431     }
 432     if (global_fs_sel > 0) return global_fs_sel;
 433     return wine_ldt_alloc_entries( 1 );
 434 }
 435
 436
 437 /***********************************************************************
 438  *           wine_ldt_init_fs
 439  *
 440  * Initialize the entry for the %fs selector of the current thread, and
 441  * set the thread %fs register.
 442  *
 443  * Note: this runs in the context of the new thread, so cannot acquire locks.
 444  */
 445 void wine_ldt_init_fs( unsigned short sel, const LDT_ENTRY *entry )
 446 {
 447     if ((sel & ~3) == (global_fs_sel & ~3))
 448     {
 449 #ifdef __linux__
 450         struct modify_ldt_s ldt_info;
 451         int ret;
 452
 453         ldt_info.entry_number = sel >> 3;
 454         fill_modify_ldt_struct( &ldt_info, entry );
 455         if ((ret = set_thread_area( &ldt_info ) < 0)) perror( "set_thread_area" );
 456 #elif defined(__APPLE__)
 457         int ret = thread_set_user_ldt( wine_ldt_get_base(entry), wine_ldt_get_limit(entry), 0 );
 458         if (ret == -1) perror( "thread_set_user_ldt" );
 459         else assert( ret == global_fs_sel );
 460 #endif  /* __APPLE__ */
 461     }
 462     else  /* LDT selector */
 463     {
 464         internal_set_entry( sel, entry );
 465     }
 466     wine_set_fs( sel );
 467 }
 468
 469
 470 /***********************************************************************
 471  *           wine_ldt_free_fs
 472  *
 473  * Free a %fs selector returned by wine_ldt_alloc_fs.
 474  */
 475 void wine_ldt_free_fs( unsigned short sel )
 476 {
 477     if (is_gdt_sel(sel)) return;  /* nothing to do */
 478     if (!((wine_get_fs() ^ sel) & ~3))
 479     {
 480         /* FIXME: if freeing current %fs we cannot acquire locks */
 481         wine_set_fs( 0 );
 482         internal_set_entry( sel, &null_entry );
 483         wine_ldt_copy.flags[sel >> 3] = 0;
 484     }
 485     else wine_ldt_free_entries( sel, 1 );
 486 }
 487
 488
 489 /***********************************************************************
 490  *           selector access functions
 491  */
 492 # ifndef _MSC_VER
 493 /* Nothing needs to be done for MS C, it will do with inline versions from the winnt.h */
 494 __ASM_GLOBAL_FUNC( wine_get_cs, "movw %cs,%ax\n\tret" )
 495 __ASM_GLOBAL_FUNC( wine_get_ds, "movw %ds,%ax\n\tret" )
 496 __ASM_GLOBAL_FUNC( wine_get_es, "movw %es,%ax\n\tret" )
 497 __ASM_GLOBAL_FUNC( wine_get_fs, "movw %fs,%ax\n\tret" )
 498 __ASM_GLOBAL_FUNC( wine_get_gs, "movw %gs,%ax\n\tret" )
 499 __ASM_GLOBAL_FUNC( wine_get_ss, "movw %ss,%ax\n\tret" )
 500 __ASM_GLOBAL_FUNC( wine_set_fs, "movl 4(%esp),%eax\n\tmovw %ax,%fs\n\tret" )
 501 __ASM_GLOBAL_FUNC( wine_set_gs, "movl 4(%esp),%eax\n\tmovw %ax,%gs\n\tret" )
 502 # endif /* defined(_MSC_VER) */
 503
 504 #endif /* __i386__ */