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 #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                             "m" (*ptr) );
  85     if (res >= 0) return res;
  86     errno = -res;
  87     return -1;
  88 }
  89
  90 static inline int set_thread_area( struct modify_ldt_s *ptr )
  91 {
  92     int res;
  93     __asm__ __volatile__( "pushl %%ebx\n\t"
  94                           "movl %3,%%ebx\n\t"
  95                           "int $0x80\n\t"
  96                           "popl %%ebx"
  97                           : "=a" (res), "=m" (*ptr)
  98                           : "0" (243) /* SYS_set_thread_area */, "q" (ptr), "m" (*ptr) );
  99     if (res >= 0) return res;
 100     errno = -res;
 101     return -1;
 102 }
 103
 104 #endif  /* linux */
 105
 106 #if defined(__svr4__) || defined(_SCO_DS)
 107 #include <sys/sysi86.h>
 108 #ifndef __sun__
 109 #include <sys/seg.h>
 110 #endif
 111 #endif
 112
 113 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__)
 114 #include <machine/segments.h>
 115
 116 extern int i386_get_ldt(int, union descriptor *, int);
 117 extern int i386_set_ldt(int, union descriptor *, int);
 118 #endif  /* __NetBSD__ || __FreeBSD__ || __OpenBSD__ */
 119
 120 #ifdef __APPLE__
 121 #include <i386/user_ldt.h>
 122 #endif
 123
 124 #endif  /* __i386__ */
 125
 126 /* local copy of the LDT */
 127 #ifdef __APPLE__
 128 struct __wine_ldt_copy wine_ldt_copy = { { 0, 0, 0 } };
 129 #else
 130 struct __wine_ldt_copy wine_ldt_copy;
 131 #endif
 132
 133 static const LDT_ENTRY null_entry;  /* all-zeros, used to clear LDT entries */
 134
 135 #define LDT_FIRST_ENTRY 512
 136 #define LDT_SIZE 8192
 137
 138 /* empty function for default locks */
 139 static void nop(void) { }
 140
 141 static void (*lock_ldt)(void) = nop;
 142 static void (*unlock_ldt)(void) = nop;
 143
 144
 145 static inline int is_gdt_sel( unsigned short sel ) { return !(sel & 4); }
 146
 147 /***********************************************************************
 148  *           wine_ldt_init_locking
 149  *
 150  * Set the LDT locking/unlocking functions.
 151  */
 152 void wine_ldt_init_locking( void (*lock_func)(void), void (*unlock_func)(void) )
 153 {
 154     lock_ldt = lock_func;
 155     unlock_ldt = unlock_func;
 156 }
 157
 158
 159 /***********************************************************************
 160  *           wine_ldt_get_entry
 161  *
 162  * Retrieve an LDT entry. Return a null entry if selector is not allocated.
 163  */
 164 void wine_ldt_get_entry( unsigned short sel, LDT_ENTRY *entry )
 165 {
 166     int index = sel >> 3;
 167
 168     if (is_gdt_sel(sel))
 169     {
 170         *entry = null_entry;
 171         return;
 172     }
 173     lock_ldt();
 174     if (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED)
 175     {
 176         wine_ldt_set_base(  entry, wine_ldt_copy.base[index] );
 177         wine_ldt_set_limit( entry, wine_ldt_copy.limit[index] );
 178         wine_ldt_set_flags( entry, wine_ldt_copy.flags[index] );
 179     }
 180     else *entry = null_entry;
 181     unlock_ldt();
 182 }
 183
 184
 185 /***********************************************************************
 186  *           internal_set_entry
 187  *
 188  * Set an LDT entry, without locking. For internal use only.
 189  */
 190 static int internal_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 191 {
 192     int ret = 0, index = sel >> 3;
 193
 194     if (index < LDT_FIRST_ENTRY) return 0;  /* cannot modify reserved entries */
 195
 196 #ifdef __i386__
 197
 198 #ifdef linux
 199     {
 200         struct modify_ldt_s ldt_info;
 201
 202         ldt_info.entry_number = index;
 203         fill_modify_ldt_struct( &ldt_info, entry );
 204         if ((ret = modify_ldt(0x11, &ldt_info, sizeof(ldt_info))) < 0)
 205             perror( "modify_ldt" );
 206     }
 207 #elif defined(__NetBSD__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__)
 208     {
 209         LDT_ENTRY entry_copy = *entry;
 210         /* The kernel will only let us set LDTs with user priority level */
 211         if (entry_copy.HighWord.Bits.Pres
 212             && entry_copy.HighWord.Bits.Dpl != 3)
 213                 entry_copy.HighWord.Bits.Dpl = 3;
 214         ret = i386_set_ldt(index, (union descriptor *)&entry_copy, 1);
 215         if (ret < 0)
 216         {
 217             perror("i386_set_ldt");
 218             fprintf( stderr, "Did you reconfigure the kernel with \"options USER_LDT\"?\n" );
 219             exit(1);
 220         }
 221     }
 222 #elif defined(__svr4__) || defined(_SCO_DS)
 223     {
 224         struct ssd ldt_mod;
 225         ldt_mod.sel  = sel;
 226         ldt_mod.bo   = (unsigned long)wine_ldt_get_base(entry);
 227         ldt_mod.ls   = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
 228         ldt_mod.acc1 = entry->HighWord.Bytes.Flags1;
 229         ldt_mod.acc2 = entry->HighWord.Bytes.Flags2 >> 4;
 230         if ((ret = sysi86(SI86DSCR, &ldt_mod)) == -1) perror("sysi86");
 231     }
 232 #elif defined(__APPLE__)
 233     if ((ret = i386_set_ldt(index, (union ldt_entry *)entry, 1)) < 0)
 234         perror("i386_set_ldt");
 235 #else
 236     fprintf( stderr, "No LDT support on this platform\n" );
 237     exit(1);
 238 #endif
 239
 240 #endif  /* __i386__ */
 241
 242     if (ret >= 0)
 243     {
 244         wine_ldt_copy.base[index]  = wine_ldt_get_base(entry);
 245         wine_ldt_copy.limit[index] = wine_ldt_get_limit(entry);
 246         wine_ldt_copy.flags[index] = (entry->HighWord.Bits.Type |
 247                                  (entry->HighWord.Bits.Default_Big ? WINE_LDT_FLAGS_32BIT : 0) |
 248                                  (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED));
 249     }
 250     return ret;
 251 }
 252
 253
 254 /***********************************************************************
 255  *           wine_ldt_set_entry
 256  *
 257  * Set an LDT entry.
 258  */
 259 int wine_ldt_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 260 {
 261     int ret;
 262
 263     lock_ldt();
 264     ret = internal_set_entry( sel, entry );
 265     unlock_ldt();
 266     return ret;
 267 }
 268
 269
 270 /***********************************************************************
 271  *           wine_ldt_is_system
 272  *
 273  * Check if the selector is a system selector (i.e. not managed by Wine).
 274  */
 275 int wine_ldt_is_system( unsigned short sel )
 276 {
 277     return is_gdt_sel(sel) || ((sel >> 3) < LDT_FIRST_ENTRY);
 278 }
 279
 280
 281 /***********************************************************************
 282  *           wine_ldt_get_ptr
 283  *
 284  * Convert a segment:offset pair to a linear pointer.
 285  * Note: we don't lock the LDT since this has to be fast.
 286  */
 287 void *wine_ldt_get_ptr( unsigned short sel, unsigned long offset )
 288 {
 289     int index;
 290
 291     if (is_gdt_sel(sel))  /* GDT selector */
 292         return (void *)offset;
 293     if ((index = (sel >> 3)) < LDT_FIRST_ENTRY)  /* system selector */
 294         return (void *)offset;
 295     if (!(wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_32BIT)) offset &= 0xffff;
 296     return (char *)wine_ldt_copy.base[index] + offset;
 297 }
 298
 299
 300 /***********************************************************************
 301  *           wine_ldt_alloc_entries
 302  *
 303  * Allocate a number of consecutive ldt entries, without setting the LDT contents.
 304  * Return a selector for the first entry.
 305  */
 306 unsigned short wine_ldt_alloc_entries( int count )
 307 {
 308     int i, index, size = 0;
 309
 310     if (count <= 0) return 0;
 311     lock_ldt();
 312     for (i = LDT_FIRST_ENTRY; i < LDT_SIZE; i++)
 313     {
 314         if (wine_ldt_copy.flags[i] & WINE_LDT_FLAGS_ALLOCATED) size = 0;
 315         else if (++size >= count)  /* found a large enough block */
 316         {
 317             index = i - size + 1;
 318
 319             /* mark selectors as allocated */
 320             for (i = 0; i < count; i++) wine_ldt_copy.flags[index + i] |= WINE_LDT_FLAGS_ALLOCATED;
 321             unlock_ldt();
 322             return (index << 3) | 7;
 323         }
 324     }
 325     unlock_ldt();
 326     return 0;
 327 }
 328
 329
 330 /***********************************************************************
 331  *           wine_ldt_realloc_entries
 332  *
 333  * Reallocate a number of consecutive ldt entries, without changing the LDT contents.
 334  * Return a selector for the first entry.
 335  */
 336 unsigned short wine_ldt_realloc_entries( unsigned short sel, int oldcount, int newcount )
 337 {
 338     int i;
 339
 340     if (oldcount < newcount)  /* we need to add selectors */
 341     {
 342         int index = sel >> 3;
 343
 344         lock_ldt();
 345         /* check if the next selectors are free */
 346         if (index + newcount > LDT_SIZE) i = oldcount;
 347         else
 348             for (i = oldcount; i < newcount; i++)
 349                 if (wine_ldt_copy.flags[index+i] & WINE_LDT_FLAGS_ALLOCATED) break;
 350
 351         if (i < newcount)  /* they are not free */
 352         {
 353             wine_ldt_free_entries( sel, oldcount );
 354             sel = wine_ldt_alloc_entries( newcount );
 355         }
 356         else  /* mark the selectors as allocated */
 357         {
 358             for (i = oldcount; i < newcount; i++)
 359                 wine_ldt_copy.flags[index+i] |= WINE_LDT_FLAGS_ALLOCATED;
 360         }
 361         unlock_ldt();
 362     }
 363     else if (oldcount > newcount) /* we need to remove selectors */
 364     {
 365         wine_ldt_free_entries( sel + (newcount << 3), newcount - oldcount );
 366     }
 367     return sel;
 368 }
 369
 370
 371 /***********************************************************************
 372  *           wine_ldt_free_entries
 373  *
 374  * Free a number of consecutive ldt entries and clear their contents.
 375  */
 376 void wine_ldt_free_entries( unsigned short sel, int count )
 377 {
 378     int index;
 379
 380     lock_ldt();
 381     for (index = sel >> 3; count > 0; count--, index++)
 382     {
 383         internal_set_entry( sel, &null_entry );
 384         wine_ldt_copy.flags[index] = 0;
 385     }
 386     unlock_ldt();
 387 }
 388
 389
 390 #ifdef __i386__
 391
 392 static int global_fs_sel = -1;  /* global selector for %fs shared among all threads */
 393
 394 /***********************************************************************
 395  *           wine_ldt_alloc_fs
 396  *
 397  * Allocate an LDT entry for a %fs selector, reusing a global
 398  * GDT selector if possible. Return the selector value.
 399  */
 400 unsigned short wine_ldt_alloc_fs(void)
 401 {
 402     if (global_fs_sel == -1)
 403     {
 404 #ifdef __linux__
 405         struct modify_ldt_s ldt_info;
 406         int ret;
 407
 408         /* the preloader may have allocated it already */
 409         global_fs_sel = wine_get_fs();
 410         if (global_fs_sel && is_gdt_sel(global_fs_sel)) return global_fs_sel;
 411
 412         ldt_info.entry_number = -1;
 413         fill_modify_ldt_struct( &ldt_info, &null_entry );
 414         if ((ret = set_thread_area( &ldt_info ) < 0))
 415         {
 416             global_fs_sel = 0;  /* don't try it again */
 417             if (errno != ENOSYS) perror( "set_thread_area" );
 418         }
 419         else global_fs_sel = (ldt_info.entry_number << 3) | 3;
 420 #endif
 421     }
 422     if (global_fs_sel > 0) return global_fs_sel;
 423     return wine_ldt_alloc_entries( 1 );
 424 }
 425
 426
 427 /***********************************************************************
 428  *           wine_ldt_init_fs
 429  *
 430  * Initialize the entry for the %fs selector of the current thread, and
 431  * set the thread %fs register.
 432  *
 433  * Note: this runs in the context of the new thread, so cannot acquire locks.
 434  */
 435 void wine_ldt_init_fs( unsigned short sel, const LDT_ENTRY *entry )
 436 {
 437     if ((sel & ~3) == (global_fs_sel & ~3))
 438     {
 439 #ifdef __linux__
 440         struct modify_ldt_s ldt_info;
 441         int ret;
 442
 443         ldt_info.entry_number = sel >> 3;
 444         fill_modify_ldt_struct( &ldt_info, entry );
 445         if ((ret = set_thread_area( &ldt_info ) < 0)) perror( "set_thread_area" );
 446 #endif
 447     }
 448     else  /* LDT selector */
 449     {
 450         internal_set_entry( sel, entry );
 451     }
 452     wine_set_fs( sel );
 453 }
 454
 455
 456 /***********************************************************************
 457  *           wine_ldt_free_fs
 458  *
 459  * Free a %fs selector returned by wine_ldt_alloc_fs.
 460  */
 461 void wine_ldt_free_fs( unsigned short sel )
 462 {
 463     if (is_gdt_sel(sel)) return;  /* nothing to do */
 464     if (!((wine_get_fs() ^ sel) & ~3))
 465     {
 466         /* FIXME: if freeing current %fs we cannot acquire locks */
 467         wine_set_fs( 0 );
 468         internal_set_entry( sel, &null_entry );
 469         wine_ldt_copy.flags[sel >> 3] = 0;
 470     }
 471     else wine_ldt_free_entries( sel, 1 );
 472 }
 473
 474
 475 /***********************************************************************
 476  *           selector access functions
 477  */
 478 # ifndef _MSC_VER
 479 /* Nothing needs to be done for MS C, it will do with inline versions from the winnt.h */
 480 __ASM_GLOBAL_FUNC( wine_get_cs, "movw %cs,%ax\n\tret" )
 481 __ASM_GLOBAL_FUNC( wine_get_ds, "movw %ds,%ax\n\tret" )
 482 __ASM_GLOBAL_FUNC( wine_get_es, "movw %es,%ax\n\tret" )
 483 __ASM_GLOBAL_FUNC( wine_get_fs, "movw %fs,%ax\n\tret" )
 484 __ASM_GLOBAL_FUNC( wine_get_gs, "movw %gs,%ax\n\tret" )
 485 __ASM_GLOBAL_FUNC( wine_get_ss, "movw %ss,%ax\n\tret" )
 486 __ASM_GLOBAL_FUNC( wine_set_fs, "movl 4(%esp),%eax\n\tmovw %ax,%fs\n\tret" )
 487 __ASM_GLOBAL_FUNC( wine_set_gs, "movl 4(%esp),%eax\n\tmovw %ax,%gs\n\tret" )
 488 # endif /* defined(_MSC_VER) */
 489
 490 #endif /* __i386__ */