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 #include <machine/sysarch.h>
 116 #endif  /* __NetBSD__ || __FreeBSD__ || __OpenBSD__ */
 117
 118 #ifdef __APPLE__
 119 #include <i386/user_ldt.h>
 120 #endif
 121
 122 #endif  /* __i386__ */
 123
 124 /* local copy of the LDT */
 125 #ifdef __APPLE__
 126 struct __wine_ldt_copy wine_ldt_copy = { { 0, 0, 0 } };
 127 #else
 128 struct __wine_ldt_copy wine_ldt_copy;
 129 #endif
 130
 131 static const LDT_ENTRY null_entry;  /* all-zeros, used to clear LDT entries */
 132
 133 #define LDT_FIRST_ENTRY 512
 134 #define LDT_SIZE 8192
 135
 136 /* empty function for default locks */
 137 static void nop(void) { }
 138
 139 static void (*lock_ldt)(void) = nop;
 140 static void (*unlock_ldt)(void) = nop;
 141
 142
 143 static inline int is_gdt_sel( unsigned short sel ) { return !(sel & 4); }
 144
 145 /***********************************************************************
 146  *           wine_ldt_init_locking
 147  *
 148  * Set the LDT locking/unlocking functions.
 149  */
 150 void wine_ldt_init_locking( void (*lock_func)(void), void (*unlock_func)(void) )
 151 {
 152     lock_ldt = lock_func;
 153     unlock_ldt = unlock_func;
 154 }
 155
 156
 157 /***********************************************************************
 158  *           wine_ldt_get_entry
 159  *
 160  * Retrieve an LDT entry. Return a null entry if selector is not allocated.
 161  */
 162 void wine_ldt_get_entry( unsigned short sel, LDT_ENTRY *entry )
 163 {
 164     int index = sel >> 3;
 165
 166     if (is_gdt_sel(sel))
 167     {
 168         *entry = null_entry;
 169         return;
 170     }
 171     lock_ldt();
 172     if (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED)
 173     {
 174         wine_ldt_set_base(  entry, wine_ldt_copy.base[index] );
 175         wine_ldt_set_limit( entry, wine_ldt_copy.limit[index] );
 176         wine_ldt_set_flags( entry, wine_ldt_copy.flags[index] );
 177     }
 178     else *entry = null_entry;
 179     unlock_ldt();
 180 }
 181
 182
 183 /***********************************************************************
 184  *           internal_set_entry
 185  *
 186  * Set an LDT entry, without locking. For internal use only.
 187  */
 188 static int internal_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 189 {
 190     int ret = 0, index = sel >> 3;
 191
 192     if (index < LDT_FIRST_ENTRY) return 0;  /* cannot modify reserved entries */
 193
 194 #ifdef __i386__
 195
 196 #ifdef linux
 197     {
 198         struct modify_ldt_s ldt_info;
 199
 200         ldt_info.entry_number = index;
 201         fill_modify_ldt_struct( &ldt_info, entry );
 202         if ((ret = modify_ldt(0x11, &ldt_info, sizeof(ldt_info))) < 0)
 203             perror( "modify_ldt" );
 204     }
 205 #elif defined(__NetBSD__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__)
 206     {
 207         LDT_ENTRY entry_copy = *entry;
 208         /* The kernel will only let us set LDTs with user priority level */
 209         if (entry_copy.HighWord.Bits.Pres
 210             && entry_copy.HighWord.Bits.Dpl != 3)
 211                 entry_copy.HighWord.Bits.Dpl = 3;
 212         ret = i386_set_ldt(index, (union descriptor *)&entry_copy, 1);
 213         if (ret < 0)
 214         {
 215             perror("i386_set_ldt");
 216             fprintf( stderr, "Did you reconfigure the kernel with \"options USER_LDT\"?\n" );
 217             exit(1);
 218         }
 219     }
 220 #elif defined(__svr4__) || defined(_SCO_DS)
 221     {
 222         struct ssd ldt_mod;
 223         ldt_mod.sel  = sel;
 224         ldt_mod.bo   = (unsigned long)wine_ldt_get_base(entry);
 225         ldt_mod.ls   = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
 226         ldt_mod.acc1 = entry->HighWord.Bytes.Flags1;
 227         ldt_mod.acc2 = entry->HighWord.Bytes.Flags2 >> 4;
 228         if ((ret = sysi86(SI86DSCR, &ldt_mod)) == -1) perror("sysi86");
 229     }
 230 #elif defined(__APPLE__)
 231     if ((ret = i386_set_ldt(index, (union ldt_entry *)entry, 1)) < 0)
 232         perror("i386_set_ldt");
 233 #else
 234     fprintf( stderr, "No LDT support on this platform\n" );
 235     exit(1);
 236 #endif
 237
 238 #endif  /* __i386__ */
 239
 240     if (ret >= 0)
 241     {
 242         wine_ldt_copy.base[index]  = wine_ldt_get_base(entry);
 243         wine_ldt_copy.limit[index] = wine_ldt_get_limit(entry);
 244         wine_ldt_copy.flags[index] = (entry->HighWord.Bits.Type |
 245                                  (entry->HighWord.Bits.Default_Big ? WINE_LDT_FLAGS_32BIT : 0) |
 246                                  (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED));
 247     }
 248     return ret;
 249 }
 250
 251
 252 /***********************************************************************
 253  *           wine_ldt_set_entry
 254  *
 255  * Set an LDT entry.
 256  */
 257 int wine_ldt_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 258 {
 259     int ret;
 260
 261     lock_ldt();
 262     ret = internal_set_entry( sel, entry );
 263     unlock_ldt();
 264     return ret;
 265 }
 266
 267
 268 /***********************************************************************
 269  *           wine_ldt_is_system
 270  *
 271  * Check if the selector is a system selector (i.e. not managed by Wine).
 272  */
 273 int wine_ldt_is_system( unsigned short sel )
 274 {
 275     return is_gdt_sel(sel) || ((sel >> 3) < LDT_FIRST_ENTRY);
 276 }
 277
 278
 279 /***********************************************************************
 280  *           wine_ldt_get_ptr
 281  *
 282  * Convert a segment:offset pair to a linear pointer.
 283  * Note: we don't lock the LDT since this has to be fast.
 284  */
 285 void *wine_ldt_get_ptr( unsigned short sel, unsigned long offset )
 286 {
 287     int index;
 288
 289     if (is_gdt_sel(sel))  /* GDT selector */
 290         return (void *)offset;
 291     if ((index = (sel >> 3)) < LDT_FIRST_ENTRY)  /* system selector */
 292         return (void *)offset;
 293     if (!(wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_32BIT)) offset &= 0xffff;
 294     return (char *)wine_ldt_copy.base[index] + offset;
 295 }
 296
 297
 298 /***********************************************************************
 299  *           wine_ldt_alloc_entries
 300  *
 301  * Allocate a number of consecutive ldt entries, without setting the LDT contents.
 302  * Return a selector for the first entry.
 303  */
 304 unsigned short wine_ldt_alloc_entries( int count )
 305 {
 306     int i, index, size = 0;
 307
 308     if (count <= 0) return 0;
 309     lock_ldt();
 310     for (i = LDT_FIRST_ENTRY; i < LDT_SIZE; i++)
 311     {
 312         if (wine_ldt_copy.flags[i] & WINE_LDT_FLAGS_ALLOCATED) size = 0;
 313         else if (++size >= count)  /* found a large enough block */
 314         {
 315             index = i - size + 1;
 316
 317             /* mark selectors as allocated */
 318             for (i = 0; i < count; i++) wine_ldt_copy.flags[index + i] |= WINE_LDT_FLAGS_ALLOCATED;
 319             unlock_ldt();
 320             return (index << 3) | 7;
 321         }
 322     }
 323     unlock_ldt();
 324     return 0;
 325 }
 326
 327
 328 /***********************************************************************
 329  *           wine_ldt_realloc_entries
 330  *
 331  * Reallocate a number of consecutive ldt entries, without changing the LDT contents.
 332  * Return a selector for the first entry.
 333  */
 334 unsigned short wine_ldt_realloc_entries( unsigned short sel, int oldcount, int newcount )
 335 {
 336     int i;
 337
 338     if (oldcount < newcount)  /* we need to add selectors */
 339     {
 340         int index = sel >> 3;
 341
 342         lock_ldt();
 343         /* check if the next selectors are free */
 344         if (index + newcount > LDT_SIZE) i = oldcount;
 345         else
 346             for (i = oldcount; i < newcount; i++)
 347                 if (wine_ldt_copy.flags[index+i] & WINE_LDT_FLAGS_ALLOCATED) break;
 348
 349         if (i < newcount)  /* they are not free */
 350         {
 351             wine_ldt_free_entries( sel, oldcount );
 352             sel = wine_ldt_alloc_entries( newcount );
 353         }
 354         else  /* mark the selectors as allocated */
 355         {
 356             for (i = oldcount; i < newcount; i++)
 357                 wine_ldt_copy.flags[index+i] |= WINE_LDT_FLAGS_ALLOCATED;
 358         }
 359         unlock_ldt();
 360     }
 361     else if (oldcount > newcount) /* we need to remove selectors */
 362     {
 363         wine_ldt_free_entries( sel + (newcount << 3), newcount - oldcount );
 364     }
 365     return sel;
 366 }
 367
 368
 369 /***********************************************************************
 370  *           wine_ldt_free_entries
 371  *
 372  * Free a number of consecutive ldt entries and clear their contents.
 373  */
 374 void wine_ldt_free_entries( unsigned short sel, int count )
 375 {
 376     int index;
 377
 378     lock_ldt();
 379     for (index = sel >> 3; count > 0; count--, index++)
 380     {
 381         internal_set_entry( sel, &null_entry );
 382         wine_ldt_copy.flags[index] = 0;
 383     }
 384     unlock_ldt();
 385 }
 386
 387
 388 #ifdef __i386__
 389
 390 static int global_fs_sel = -1;  /* global selector for %fs shared among all threads */
 391
 392 /***********************************************************************
 393  *           wine_ldt_alloc_fs
 394  *
 395  * Allocate an LDT entry for a %fs selector, reusing a global
 396  * GDT selector if possible. Return the selector value.
 397  */
 398 unsigned short wine_ldt_alloc_fs(void)
 399 {
 400     if (global_fs_sel == -1)
 401     {
 402 #ifdef __linux__
 403         struct modify_ldt_s ldt_info;
 404         int ret;
 405
 406         /* the preloader may have allocated it already */
 407         global_fs_sel = wine_get_fs();
 408         if (global_fs_sel && is_gdt_sel(global_fs_sel)) return global_fs_sel;
 409
 410         ldt_info.entry_number = -1;
 411         fill_modify_ldt_struct( &ldt_info, &null_entry );
 412         if ((ret = set_thread_area( &ldt_info ) < 0))
 413         {
 414             global_fs_sel = 0;  /* don't try it again */
 415             if (errno != ENOSYS) perror( "set_thread_area" );
 416         }
 417         else global_fs_sel = (ldt_info.entry_number << 3) | 3;
 418 #elif defined(__FreeBSD__)
 419         global_fs_sel = GSEL( GUFS_SEL, SEL_UPL );
 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 #elif defined(__FreeBSD__)
 447         i386_set_fsbase( wine_ldt_get_base( entry ));
 448 #endif
 449     }
 450     else  /* LDT selector */
 451     {
 452         internal_set_entry( sel, entry );
 453     }
 454     wine_set_fs( sel );
 455 }
 456
 457
 458 /***********************************************************************
 459  *           wine_ldt_free_fs
 460  *
 461  * Free a %fs selector returned by wine_ldt_alloc_fs.
 462  */
 463 void wine_ldt_free_fs( unsigned short sel )
 464 {
 465     if (is_gdt_sel(sel)) return;  /* nothing to do */
 466     if (!((wine_get_fs() ^ sel) & ~3))
 467     {
 468         /* FIXME: if freeing current %fs we cannot acquire locks */
 469         wine_set_fs( 0 );
 470         internal_set_entry( sel, &null_entry );
 471         wine_ldt_copy.flags[sel >> 3] = 0;
 472     }
 473     else wine_ldt_free_entries( sel, 1 );
 474 }
 475
 476
 477 /***********************************************************************
 478  *           selector access functions
 479  */
 480 # ifndef _MSC_VER
 481 /* Nothing needs to be done for MS C, it will do with inline versions from the winnt.h */
 482 __ASM_GLOBAL_FUNC( wine_get_cs, "movw %cs,%ax\n\tret" )
 483 __ASM_GLOBAL_FUNC( wine_get_ds, "movw %ds,%ax\n\tret" )
 484 __ASM_GLOBAL_FUNC( wine_get_es, "movw %es,%ax\n\tret" )
 485 __ASM_GLOBAL_FUNC( wine_get_fs, "movw %fs,%ax\n\tret" )
 486 __ASM_GLOBAL_FUNC( wine_get_gs, "movw %gs,%ax\n\tret" )
 487 __ASM_GLOBAL_FUNC( wine_get_ss, "movw %ss,%ax\n\tret" )
 488 __ASM_GLOBAL_FUNC( wine_set_fs, "movl 4(%esp),%eax\n\tmovw %ax,%fs\n\tret" )
 489 __ASM_GLOBAL_FUNC( wine_set_gs, "movl 4(%esp),%eax\n\tmovw %ax,%gs\n\tret" )
 490 # endif /* defined(_MSC_VER) */
 491
 492 #endif /* __i386__ */