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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, 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 #include "wine/library.h"
  35
  36 #ifdef __i386__
  37
  38 #ifdef __linux__
  39
  40 #ifdef HAVE_SYS_SYSCALL_H
  41 # include <sys/syscall.h>
  42 #endif
  43
  44 struct modify_ldt_s
  45 {
  46     unsigned int  entry_number;
  47     unsigned long base_addr;
  48     unsigned int  limit;
  49     unsigned int  seg_32bit : 1;
  50     unsigned int  contents : 2;
  51     unsigned int  read_exec_only : 1;
  52     unsigned int  limit_in_pages : 1;
  53     unsigned int  seg_not_present : 1;
  54     unsigned int  usable : 1;
  55     unsigned int  garbage : 25;
  56 };
  57
  58 static inline void fill_modify_ldt_struct( struct modify_ldt_s *ptr, const LDT_ENTRY *entry )
  59 {
  60     ptr->base_addr       = (unsigned long)wine_ldt_get_base(entry);
  61     ptr->limit           = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
  62     ptr->seg_32bit       = entry->HighWord.Bits.Default_Big;
  63     ptr->contents        = (entry->HighWord.Bits.Type >> 2) & 3;
  64     ptr->read_exec_only  = !(entry->HighWord.Bits.Type & 2);
  65     ptr->limit_in_pages  = entry->HighWord.Bits.Granularity;
  66     ptr->seg_not_present = !entry->HighWord.Bits.Pres;
  67     ptr->usable          = entry->HighWord.Bits.Sys;
  68     ptr->garbage         = 0;
  69 }
  70
  71 static inline int modify_ldt( int func, struct modify_ldt_s *ptr, unsigned long count )
  72 {
  73     int res;
  74     __asm__ __volatile__( "pushl %%ebx\n\t"
  75                           "movl %2,%%ebx\n\t"
  76                           "int $0x80\n\t"
  77                           "popl %%ebx"
  78                           : "=a" (res)
  79                           : "0" (SYS_modify_ldt),
  80                             "r" (func),
  81                             "c" (ptr),
  82                             "d" (count),
  83                             "m" (*ptr) );
  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 %3,%%ebx\n\t"
  94                           "int $0x80\n\t"
  95                           "popl %%ebx"
  96                           : "=a" (res), "=m" (*ptr)
  97                           : "0" (243) /* SYS_set_thread_area */, "q" (ptr), "m" (*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(__FreeBSD_kernel__) || defined(__OpenBSD__)
 113 #include <machine/segments.h>
 114 #include <machine/sysarch.h>
 115 #endif  /* __NetBSD__ || __FreeBSD__ || __OpenBSD__ */
 116
 117 #ifdef __APPLE__
 118 #include <i386/user_ldt.h>
 119 #endif
 120
 121 #endif  /* __i386__ */
 122
 123 /* local copy of the LDT */
 124 #ifdef __APPLE__
 125 struct __wine_ldt_copy wine_ldt_copy = { { 0, 0, 0 } };
 126 #else
 127 struct __wine_ldt_copy wine_ldt_copy;
 128 #endif
 129
 130 static const LDT_ENTRY null_entry;  /* all-zeros, used to clear LDT entries */
 131
 132 #define LDT_FIRST_ENTRY 512
 133 #define LDT_SIZE 8192
 134
 135 /* empty function for default locks */
 136 static void nop(void) { }
 137
 138 static void (*lock_ldt)(void) = nop;
 139 static void (*unlock_ldt)(void) = nop;
 140
 141
 142 static inline int is_gdt_sel( unsigned short sel ) { return !(sel & 4); }
 143
 144 /***********************************************************************
 145  *           wine_ldt_init_locking
 146  *
 147  * Set the LDT locking/unlocking functions.
 148  */
 149 void wine_ldt_init_locking( void (*lock_func)(void), void (*unlock_func)(void) )
 150 {
 151     lock_ldt = lock_func;
 152     unlock_ldt = unlock_func;
 153 }
 154
 155
 156 /***********************************************************************
 157  *           wine_ldt_get_entry
 158  *
 159  * Retrieve an LDT entry. Return a null entry if selector is not allocated.
 160  */
 161 void wine_ldt_get_entry( unsigned short sel, LDT_ENTRY *entry )
 162 {
 163     int index = sel >> 3;
 164
 165     if (is_gdt_sel(sel))
 166     {
 167         *entry = null_entry;
 168         return;
 169     }
 170     lock_ldt();
 171     if (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED)
 172     {
 173         wine_ldt_set_base(  entry, wine_ldt_copy.base[index] );
 174         wine_ldt_set_limit( entry, wine_ldt_copy.limit[index] );
 175         wine_ldt_set_flags( entry, wine_ldt_copy.flags[index] );
 176     }
 177     else *entry = null_entry;
 178     unlock_ldt();
 179 }
 180
 181
 182 /***********************************************************************
 183  *           internal_set_entry
 184  *
 185  * Set an LDT entry, without locking. For internal use only.
 186  */
 187 static int internal_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 188 {
 189     int ret = 0, index = sel >> 3;
 190
 191     if (index < LDT_FIRST_ENTRY) return 0;  /* cannot modify reserved entries */
 192
 193 #ifdef __i386__
 194
 195 #ifdef linux
 196     {
 197         struct modify_ldt_s ldt_info;
 198
 199         ldt_info.entry_number = index;
 200         fill_modify_ldt_struct( &ldt_info, entry );
 201         if ((ret = modify_ldt(0x11, &ldt_info, sizeof(ldt_info))) < 0)
 202             perror( "modify_ldt" );
 203     }
 204 #elif defined(__NetBSD__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__)
 205     {
 206         LDT_ENTRY entry_copy = *entry;
 207         /* The kernel will only let us set LDTs with user priority level */
 208         if (entry_copy.HighWord.Bits.Pres
 209             && entry_copy.HighWord.Bits.Dpl != 3)
 210                 entry_copy.HighWord.Bits.Dpl = 3;
 211         ret = i386_set_ldt(index, (union descriptor *)&entry_copy, 1);
 212         if (ret < 0)
 213         {
 214             perror("i386_set_ldt");
 215             fprintf( stderr, "Did you reconfigure the kernel with \"options USER_LDT\"?\n" );
 216             exit(1);
 217         }
 218     }
 219 #elif defined(__svr4__) || defined(_SCO_DS)
 220     {
 221         struct ssd ldt_mod;
 222         ldt_mod.sel  = sel;
 223         ldt_mod.bo   = (unsigned long)wine_ldt_get_base(entry);
 224         ldt_mod.ls   = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
 225         ldt_mod.acc1 = entry->HighWord.Bytes.Flags1;
 226         ldt_mod.acc2 = entry->HighWord.Bytes.Flags2 >> 4;
 227         if ((ret = sysi86(SI86DSCR, &ldt_mod)) == -1) perror("sysi86");
 228     }
 229 #elif defined(__APPLE__)
 230     if ((ret = i386_set_ldt(index, (union ldt_entry *)entry, 1)) < 0)
 231         perror("i386_set_ldt");
 232 #else
 233     fprintf( stderr, "No LDT support on this platform\n" );
 234     exit(1);
 235 #endif
 236
 237 #endif  /* __i386__ */
 238
 239     if (ret >= 0)
 240     {
 241         wine_ldt_copy.base[index]  = wine_ldt_get_base(entry);
 242         wine_ldt_copy.limit[index] = wine_ldt_get_limit(entry);
 243         wine_ldt_copy.flags[index] = (entry->HighWord.Bits.Type |
 244                                  (entry->HighWord.Bits.Default_Big ? WINE_LDT_FLAGS_32BIT : 0) |
 245                                  (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED));
 246     }
 247     return ret;
 248 }
 249
 250
 251 /***********************************************************************
 252  *           wine_ldt_set_entry
 253  *
 254  * Set an LDT entry.
 255  */
 256 int wine_ldt_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 257 {
 258     int ret;
 259
 260     lock_ldt();
 261     ret = internal_set_entry( sel, entry );
 262     unlock_ldt();
 263     return ret;
 264 }
 265
 266
 267 /***********************************************************************
 268  *           wine_ldt_is_system
 269  *
 270  * Check if the selector is a system selector (i.e. not managed by Wine).
 271  */
 272 int wine_ldt_is_system( unsigned short sel )
 273 {
 274     return is_gdt_sel(sel) || ((sel >> 3) < LDT_FIRST_ENTRY);
 275 }
 276
 277
 278 /***********************************************************************
 279  *           wine_ldt_get_ptr
 280  *
 281  * Convert a segment:offset pair to a linear pointer.
 282  * Note: we don't lock the LDT since this has to be fast.
 283  */
 284 void *wine_ldt_get_ptr( unsigned short sel, unsigned long offset )
 285 {
 286     int index;
 287
 288     if (is_gdt_sel(sel))  /* GDT selector */
 289         return (void *)offset;
 290     if ((index = (sel >> 3)) < LDT_FIRST_ENTRY)  /* system selector */
 291         return (void *)offset;
 292     if (!(wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_32BIT)) offset &= 0xffff;
 293     return (char *)wine_ldt_copy.base[index] + offset;
 294 }
 295
 296
 297 /***********************************************************************
 298  *           wine_ldt_alloc_entries
 299  *
 300  * Allocate a number of consecutive ldt entries, without setting the LDT contents.
 301  * Return a selector for the first entry.
 302  */
 303 unsigned short wine_ldt_alloc_entries( int count )
 304 {
 305     int i, index, size = 0;
 306
 307     if (count <= 0) return 0;
 308     lock_ldt();
 309     for (i = LDT_FIRST_ENTRY; i < LDT_SIZE; i++)
 310     {
 311         if (wine_ldt_copy.flags[i] & WINE_LDT_FLAGS_ALLOCATED) size = 0;
 312         else if (++size >= count)  /* found a large enough block */
 313         {
 314             index = i - size + 1;
 315
 316             /* mark selectors as allocated */
 317             for (i = 0; i < count; i++) wine_ldt_copy.flags[index + i] |= WINE_LDT_FLAGS_ALLOCATED;
 318             unlock_ldt();
 319             return (index << 3) | 7;
 320         }
 321     }
 322     unlock_ldt();
 323     return 0;
 324 }
 325
 326
 327 /***********************************************************************
 328  *           wine_ldt_realloc_entries
 329  *
 330  * Reallocate a number of consecutive ldt entries, without changing the LDT contents.
 331  * Return a selector for the first entry.
 332  */
 333 unsigned short wine_ldt_realloc_entries( unsigned short sel, int oldcount, int newcount )
 334 {
 335     int i;
 336
 337     if (oldcount < newcount)  /* we need to add selectors */
 338     {
 339         int index = sel >> 3;
 340
 341         lock_ldt();
 342         /* check if the next selectors are free */
 343         if (index + newcount > LDT_SIZE) i = oldcount;
 344         else
 345             for (i = oldcount; i < newcount; i++)
 346                 if (wine_ldt_copy.flags[index+i] & WINE_LDT_FLAGS_ALLOCATED) break;
 347
 348         if (i < newcount)  /* they are not free */
 349         {
 350             wine_ldt_free_entries( sel, oldcount );
 351             sel = wine_ldt_alloc_entries( newcount );
 352         }
 353         else  /* mark the selectors as allocated */
 354         {
 355             for (i = oldcount; i < newcount; i++)
 356                 wine_ldt_copy.flags[index+i] |= WINE_LDT_FLAGS_ALLOCATED;
 357         }
 358         unlock_ldt();
 359     }
 360     else if (oldcount > newcount) /* we need to remove selectors */
 361     {
 362         wine_ldt_free_entries( sel + (newcount << 3), newcount - oldcount );
 363     }
 364     return sel;
 365 }
 366
 367
 368 /***********************************************************************
 369  *           wine_ldt_free_entries
 370  *
 371  * Free a number of consecutive ldt entries and clear their contents.
 372  */
 373 void wine_ldt_free_entries( unsigned short sel, int count )
 374 {
 375     int index;
 376
 377     lock_ldt();
 378     for (index = sel >> 3; count > 0; count--, index++)
 379     {
 380         internal_set_entry( sel, &null_entry );
 381         wine_ldt_copy.flags[index] = 0;
 382     }
 383     unlock_ldt();
 384 }
 385
 386
 387 #if defined(__i386__) && !defined(__MINGW32__) && !defined(_MSC_VER)
 388
 389 static int global_fs_sel = -1;  /* global selector for %fs shared among all threads */
 390
 391 /***********************************************************************
 392  *           wine_ldt_alloc_fs
 393  *
 394  * Allocate an LDT entry for a %fs selector, reusing a global
 395  * GDT selector if possible. Return the selector value.
 396  */
 397 unsigned short wine_ldt_alloc_fs(void)
 398 {
 399     if (global_fs_sel == -1)
 400     {
 401 #ifdef __linux__
 402         struct modify_ldt_s ldt_info;
 403         int ret;
 404
 405         /* the preloader may have allocated it already */
 406         global_fs_sel = wine_get_fs();
 407         if (global_fs_sel && is_gdt_sel(global_fs_sel)) return global_fs_sel;
 408
 409         ldt_info.entry_number = -1;
 410         fill_modify_ldt_struct( &ldt_info, &null_entry );
 411         if ((ret = set_thread_area( &ldt_info ) < 0))
 412         {
 413             global_fs_sel = 0;  /* don't try it again */
 414             if (errno != ENOSYS) perror( "set_thread_area" );
 415         }
 416         else global_fs_sel = (ldt_info.entry_number << 3) | 3;
 417 #elif defined(__FreeBSD__)
 418         global_fs_sel = GSEL( GUFS_SEL, SEL_UPL );
 419 #endif
 420     }
 421     if (global_fs_sel > 0) return global_fs_sel;
 422     return wine_ldt_alloc_entries( 1 );
 423 }
 424
 425
 426 /***********************************************************************
 427  *           wine_ldt_init_fs
 428  *
 429  * Initialize the entry for the %fs selector of the current thread, and
 430  * set the thread %fs register.
 431  *
 432  * Note: this runs in the context of the new thread, so cannot acquire locks.
 433  */
 434 void wine_ldt_init_fs( unsigned short sel, const LDT_ENTRY *entry )
 435 {
 436     if ((sel & ~3) == (global_fs_sel & ~3))
 437     {
 438 #ifdef __linux__
 439         struct modify_ldt_s ldt_info;
 440         int ret;
 441
 442         ldt_info.entry_number = sel >> 3;
 443         fill_modify_ldt_struct( &ldt_info, entry );
 444         if ((ret = set_thread_area( &ldt_info ) < 0)) perror( "set_thread_area" );
 445 #elif defined(__FreeBSD__)
 446         i386_set_fsbase( wine_ldt_get_base( entry ));
 447 #endif
 448     }
 449     else  /* LDT selector */
 450     {
 451         internal_set_entry( sel, entry );
 452     }
 453     wine_set_fs( sel );
 454 }
 455
 456
 457 /***********************************************************************
 458  *           wine_ldt_free_fs
 459  *
 460  * Free a %fs selector returned by wine_ldt_alloc_fs.
 461  */
 462 void wine_ldt_free_fs( unsigned short sel )
 463 {
 464     if (is_gdt_sel(sel)) return;  /* nothing to do */
 465     if (!((wine_get_fs() ^ sel) & ~3))
 466     {
 467         /* FIXME: if freeing current %fs we cannot acquire locks */
 468         wine_set_fs( 0 );
 469         internal_set_entry( sel, &null_entry );
 470         wine_ldt_copy.flags[sel >> 3] = 0;
 471     }
 472     else wine_ldt_free_entries( sel, 1 );
 473 }
 474
 475
 476 /***********************************************************************
 477  *           selector access functions
 478  */
 479 __ASM_GLOBAL_FUNC( wine_get_cs, "movw %cs,%ax\n\tret" )
 480 __ASM_GLOBAL_FUNC( wine_get_ds, "movw %ds,%ax\n\tret" )
 481 __ASM_GLOBAL_FUNC( wine_get_es, "movw %es,%ax\n\tret" )
 482 __ASM_GLOBAL_FUNC( wine_get_fs, "movw %fs,%ax\n\tret" )
 483 __ASM_GLOBAL_FUNC( wine_get_gs, "movw %gs,%ax\n\tret" )
 484 __ASM_GLOBAL_FUNC( wine_get_ss, "movw %ss,%ax\n\tret" )
 485 __ASM_GLOBAL_FUNC( wine_set_fs, "movl 4(%esp),%eax\n\tmovw %ax,%fs\n\tret" )
 486 __ASM_GLOBAL_FUNC( wine_set_gs, "movl 4(%esp),%eax\n\tmovw %ax,%gs\n\tret" )
 487
 488 #endif /* __i386__ */