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