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 #if defined(__i386__) && !defined(__MINGW32__) && !defined(_MSC_VER)
  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     return syscall( 123 /* SYS_modify_ldt */, func, ptr, count );
  74 }
  75
  76 static inline int set_thread_area( struct modify_ldt_s *ptr )
  77 {
  78     return syscall( 243 /* SYS_set_thread_area */, ptr );
  79 }
  80
  81 #endif  /* linux */
  82
  83 #if defined(__svr4__) || defined(_SCO_DS)
  84 #include <sys/sysi86.h>
  85 #ifndef __sun__
  86 #include <sys/seg.h>
  87 #endif
  88 #endif
  89
  90 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__) || defined(__DragonFly__)
  91 #include <machine/segments.h>
  92 #include <machine/sysarch.h>
  93 #endif  /* __NetBSD__ || __FreeBSD__ || __OpenBSD__ */
  94
  95 #ifdef __GNU__
  96 #include <mach/i386/mach_i386.h>
  97 #include <mach/mach_traps.h>
  98 #endif
  99
 100 #ifdef __APPLE__
 101 #include <i386/user_ldt.h>
 102 #endif
 103
 104 /* local copy of the LDT */
 105 #ifdef __APPLE__
 106 struct __wine_ldt_copy wine_ldt_copy = { { 0, 0, 0 } };
 107 #else
 108 struct __wine_ldt_copy wine_ldt_copy;
 109 #endif
 110
 111 static const LDT_ENTRY null_entry;  /* all-zeros, used to clear LDT entries */
 112
 113 #define LDT_FIRST_ENTRY 512
 114 #define LDT_SIZE 8192
 115
 116 /* empty function for default locks */
 117 static void nop(void) { }
 118
 119 static void (*lock_ldt)(void) = nop;
 120 static void (*unlock_ldt)(void) = nop;
 121
 122
 123 static inline int is_gdt_sel( unsigned short sel ) { return !(sel & 4); }
 124
 125 /***********************************************************************
 126  *           wine_ldt_init_locking
 127  *
 128  * Set the LDT locking/unlocking functions.
 129  */
 130 void wine_ldt_init_locking( void (*lock_func)(void), void (*unlock_func)(void) )
 131 {
 132     lock_ldt = lock_func;
 133     unlock_ldt = unlock_func;
 134 }
 135
 136
 137 /***********************************************************************
 138  *           wine_ldt_get_entry
 139  *
 140  * Retrieve an LDT entry. Return a null entry if selector is not allocated.
 141  */
 142 void wine_ldt_get_entry( unsigned short sel, LDT_ENTRY *entry )
 143 {
 144     int index = sel >> 3;
 145
 146     if (is_gdt_sel(sel))
 147     {
 148         *entry = null_entry;
 149         return;
 150     }
 151     lock_ldt();
 152     if (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED)
 153     {
 154         wine_ldt_set_base(  entry, wine_ldt_copy.base[index] );
 155         wine_ldt_set_limit( entry, wine_ldt_copy.limit[index] );
 156         wine_ldt_set_flags( entry, wine_ldt_copy.flags[index] );
 157     }
 158     else *entry = null_entry;
 159     unlock_ldt();
 160 }
 161
 162
 163 /***********************************************************************
 164  *           internal_set_entry
 165  *
 166  * Set an LDT entry, without locking. For internal use only.
 167  */
 168 static int internal_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 169 {
 170     int ret = 0, index = sel >> 3;
 171
 172     if (index < LDT_FIRST_ENTRY) return 0;  /* cannot modify reserved entries */
 173
 174 #ifdef linux
 175     {
 176         struct modify_ldt_s ldt_info;
 177
 178         ldt_info.entry_number = index;
 179         fill_modify_ldt_struct( &ldt_info, entry );
 180         if ((ret = modify_ldt(0x11, &ldt_info, sizeof(ldt_info))) < 0)
 181             perror( "modify_ldt" );
 182     }
 183 #elif defined(__NetBSD__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__) || defined(__DragonFly__)
 184     {
 185         LDT_ENTRY entry_copy = *entry;
 186         /* The kernel will only let us set LDTs with user priority level */
 187         if (entry_copy.HighWord.Bits.Pres
 188             && entry_copy.HighWord.Bits.Dpl != 3)
 189                 entry_copy.HighWord.Bits.Dpl = 3;
 190         ret = i386_set_ldt(index, (union descriptor *)&entry_copy, 1);
 191         if (ret < 0)
 192         {
 193             perror("i386_set_ldt");
 194             fprintf( stderr, "Did you reconfigure the kernel with \"options USER_LDT\"?\n" );
 195             exit(1);
 196         }
 197     }
 198 #elif defined(__svr4__) || defined(_SCO_DS)
 199     {
 200         struct ssd ldt_mod;
 201         ldt_mod.sel  = sel;
 202         ldt_mod.bo   = (unsigned long)wine_ldt_get_base(entry);
 203         ldt_mod.ls   = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
 204         ldt_mod.acc1 = entry->HighWord.Bytes.Flags1;
 205         ldt_mod.acc2 = entry->HighWord.Bytes.Flags2 >> 4;
 206         if ((ret = sysi86(SI86DSCR, &ldt_mod)) == -1) perror("sysi86");
 207     }
 208 #elif defined(__APPLE__)
 209     if ((ret = i386_set_ldt(index, (union ldt_entry *)entry, 1)) < 0)
 210         perror("i386_set_ldt");
 211 #elif defined(__GNU__)
 212     if ((ret = i386_set_ldt(mach_thread_self(), sel, (descriptor_list_t)entry, 1)) != KERN_SUCCESS)
 213         perror("i386_set_ldt");
 214 #else
 215     fprintf( stderr, "No LDT support on this platform\n" );
 216     exit(1);
 217 #endif
 218
 219     if (ret >= 0)
 220     {
 221         wine_ldt_copy.base[index]  = wine_ldt_get_base(entry);
 222         wine_ldt_copy.limit[index] = wine_ldt_get_limit(entry);
 223         wine_ldt_copy.flags[index] = (entry->HighWord.Bits.Type |
 224                                  (entry->HighWord.Bits.Default_Big ? WINE_LDT_FLAGS_32BIT : 0) |
 225                                  (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED));
 226     }
 227     return ret;
 228 }
 229
 230
 231 /***********************************************************************
 232  *           wine_ldt_set_entry
 233  *
 234  * Set an LDT entry.
 235  */
 236 int wine_ldt_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 237 {
 238     int ret;
 239
 240     lock_ldt();
 241     ret = internal_set_entry( sel, entry );
 242     unlock_ldt();
 243     return ret;
 244 }
 245
 246
 247 /***********************************************************************
 248  *           wine_ldt_is_system
 249  *
 250  * Check if the selector is a system selector (i.e. not managed by Wine).
 251  */
 252 int wine_ldt_is_system( unsigned short sel )
 253 {
 254     return is_gdt_sel(sel) || ((sel >> 3) < LDT_FIRST_ENTRY);
 255 }
 256
 257
 258 /***********************************************************************
 259  *           wine_ldt_get_ptr
 260  *
 261  * Convert a segment:offset pair to a linear pointer.
 262  * Note: we don't lock the LDT since this has to be fast.
 263  */
 264 void *wine_ldt_get_ptr( unsigned short sel, unsigned long offset )
 265 {
 266     int index;
 267
 268     if (is_gdt_sel(sel))  /* GDT selector */
 269         return (void *)offset;
 270     if ((index = (sel >> 3)) < LDT_FIRST_ENTRY)  /* system selector */
 271         return (void *)offset;
 272     if (!(wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_32BIT)) offset &= 0xffff;
 273     return (char *)wine_ldt_copy.base[index] + offset;
 274 }
 275
 276
 277 /***********************************************************************
 278  *           wine_ldt_alloc_entries
 279  *
 280  * Allocate a number of consecutive ldt entries, without setting the LDT contents.
 281  * Return a selector for the first entry.
 282  */
 283 unsigned short wine_ldt_alloc_entries( int count )
 284 {
 285     int i, index, size = 0;
 286
 287     if (count <= 0) return 0;
 288     lock_ldt();
 289     for (i = LDT_FIRST_ENTRY; i < LDT_SIZE; i++)
 290     {
 291         if (wine_ldt_copy.flags[i] & WINE_LDT_FLAGS_ALLOCATED) size = 0;
 292         else if (++size >= count)  /* found a large enough block */
 293         {
 294             index = i - size + 1;
 295
 296             /* mark selectors as allocated */
 297             for (i = 0; i < count; i++) wine_ldt_copy.flags[index + i] |= WINE_LDT_FLAGS_ALLOCATED;
 298             unlock_ldt();
 299             return (index << 3) | 7;
 300         }
 301     }
 302     unlock_ldt();
 303     return 0;
 304 }
 305
 306
 307 /***********************************************************************
 308  *           wine_ldt_realloc_entries
 309  *
 310  * Reallocate a number of consecutive ldt entries, without changing the LDT contents.
 311  * Return a selector for the first entry.
 312  */
 313 unsigned short wine_ldt_realloc_entries( unsigned short sel, int oldcount, int newcount )
 314 {
 315     int i;
 316
 317     if (oldcount < newcount)  /* we need to add selectors */
 318     {
 319         int index = sel >> 3;
 320
 321         lock_ldt();
 322         /* check if the next selectors are free */
 323         if (index + newcount > LDT_SIZE) i = oldcount;
 324         else
 325             for (i = oldcount; i < newcount; i++)
 326                 if (wine_ldt_copy.flags[index+i] & WINE_LDT_FLAGS_ALLOCATED) break;
 327
 328         if (i < newcount)  /* they are not free */
 329         {
 330             wine_ldt_free_entries( sel, oldcount );
 331             sel = wine_ldt_alloc_entries( newcount );
 332         }
 333         else  /* mark the selectors as allocated */
 334         {
 335             for (i = oldcount; i < newcount; i++)
 336                 wine_ldt_copy.flags[index+i] |= WINE_LDT_FLAGS_ALLOCATED;
 337         }
 338         unlock_ldt();
 339     }
 340     else if (oldcount > newcount) /* we need to remove selectors */
 341     {
 342         wine_ldt_free_entries( sel + (newcount << 3), newcount - oldcount );
 343     }
 344     return sel;
 345 }
 346
 347
 348 /***********************************************************************
 349  *           wine_ldt_free_entries
 350  *
 351  * Free a number of consecutive ldt entries and clear their contents.
 352  */
 353 void wine_ldt_free_entries( unsigned short sel, int count )
 354 {
 355     int index;
 356
 357     lock_ldt();
 358     for (index = sel >> 3; count > 0; count--, index++)
 359     {
 360         internal_set_entry( sel, &null_entry );
 361         wine_ldt_copy.flags[index] = 0;
 362     }
 363     unlock_ldt();
 364 }
 365
 366
 367 static int global_fs_sel = -1;  /* global selector for %fs shared among all threads */
 368
 369 /***********************************************************************
 370  *           wine_ldt_alloc_fs
 371  *
 372  * Allocate an LDT entry for a %fs selector, reusing a global
 373  * GDT selector if possible. Return the selector value.
 374  */
 375 unsigned short wine_ldt_alloc_fs(void)
 376 {
 377     if (global_fs_sel == -1)
 378     {
 379 #ifdef __linux__
 380         struct modify_ldt_s ldt_info;
 381         int ret;
 382
 383         /* the preloader may have allocated it already */
 384         global_fs_sel = wine_get_fs();
 385         if (global_fs_sel && is_gdt_sel(global_fs_sel)) return global_fs_sel;
 386
 387         memset( &ldt_info, 0, sizeof(ldt_info) );
 388         ldt_info.entry_number = -1;
 389         ldt_info.seg_32bit = 1;
 390         ldt_info.usable = 1;
 391         if ((ret = set_thread_area( &ldt_info ) < 0))
 392         {
 393             global_fs_sel = 0;  /* don't try it again */
 394             if (errno != ENOSYS) perror( "set_thread_area" );
 395         }
 396         else global_fs_sel = (ldt_info.entry_number << 3) | 3;
 397 #elif defined(__FreeBSD__) || defined (__FreeBSD_kernel__)
 398         global_fs_sel = GSEL( GUFS_SEL, SEL_UPL );
 399 #endif
 400     }
 401     if (global_fs_sel > 0) return global_fs_sel;
 402     return wine_ldt_alloc_entries( 1 );
 403 }
 404
 405
 406 /***********************************************************************
 407  *           wine_ldt_init_fs
 408  *
 409  * Initialize the entry for the %fs selector of the current thread, and
 410  * set the thread %fs register.
 411  *
 412  * Note: this runs in the context of the new thread, so cannot acquire locks.
 413  */
 414 void wine_ldt_init_fs( unsigned short sel, const LDT_ENTRY *entry )
 415 {
 416     if ((sel & ~3) == (global_fs_sel & ~3))
 417     {
 418 #ifdef __linux__
 419         struct modify_ldt_s ldt_info;
 420         int ret;
 421
 422         ldt_info.entry_number = sel >> 3;
 423         fill_modify_ldt_struct( &ldt_info, entry );
 424         if ((ret = set_thread_area( &ldt_info ) < 0)) perror( "set_thread_area" );
 425 #elif defined(__FreeBSD__) || defined (__FreeBSD_kernel__) || defined(__DragonFly__)
 426         i386_set_fsbase( wine_ldt_get_base( entry ));
 427 #endif
 428     }
 429     else  /* LDT selector */
 430     {
 431         internal_set_entry( sel, entry );
 432     }
 433     wine_set_fs( sel );
 434 }
 435
 436
 437 /***********************************************************************
 438  *           wine_ldt_free_fs
 439  *
 440  * Free a %fs selector returned by wine_ldt_alloc_fs.
 441  */
 442 void wine_ldt_free_fs( unsigned short sel )
 443 {
 444     if (is_gdt_sel(sel)) return;  /* nothing to do */
 445     if (!((wine_get_fs() ^ sel) & ~3))
 446     {
 447         /* FIXME: if freeing current %fs we cannot acquire locks */
 448         wine_set_fs( 0 );
 449         internal_set_entry( sel, &null_entry );
 450         wine_ldt_copy.flags[sel >> 3] = 0;
 451     }
 452     else wine_ldt_free_entries( sel, 1 );
 453 }
 454
 455
 456 /***********************************************************************
 457  *           selector access functions
 458  */
 459 __ASM_GLOBAL_FUNC( wine_get_cs, "movw %cs,%ax\n\tret" )
 460 __ASM_GLOBAL_FUNC( wine_get_ds, "movw %ds,%ax\n\tret" )
 461 __ASM_GLOBAL_FUNC( wine_get_es, "movw %es,%ax\n\tret" )
 462 __ASM_GLOBAL_FUNC( wine_get_fs, "movw %fs,%ax\n\tret" )
 463 __ASM_GLOBAL_FUNC( wine_get_gs, "movw %gs,%ax\n\tret" )
 464 __ASM_GLOBAL_FUNC( wine_get_ss, "movw %ss,%ax\n\tret" )
 465 __ASM_GLOBAL_FUNC( wine_set_fs, "movl 4(%esp),%eax\n\tmovw %ax,%fs\n\tret" )
 466 __ASM_GLOBAL_FUNC( wine_set_gs, "movl 4(%esp),%eax\n\tmovw %ax,%gs\n\tret" )
 467
 468 #endif /* __i386__ */