library/ldt.c

   1 /*
   2  * LDT manipulation functions
   3  *
   4  * Copyright 1993 Robert J. Amstadt
   5  * Copyright 1995 Alexandre Julliard
   6  */
   7
   8 #include "config.h"
   9
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include <string.h>
  13 #include <errno.h>
  14
  15 #include "winbase.h"
  16 #include "wine/library.h"
  17
  18 #ifdef __i386__
  19
  20 #ifdef linux
  21
  22 #ifdef HAVE_SYS_SYSCALL_H
  23 # include <sys/syscall.h>
  24 #endif
  25
  26 struct modify_ldt_s
  27 {
  28     unsigned int  entry_number;
  29     unsigned long base_addr;
  30     unsigned int  limit;
  31     unsigned int  seg_32bit : 1;
  32     unsigned int  contents : 2;
  33     unsigned int  read_exec_only : 1;
  34     unsigned int  limit_in_pages : 1;
  35     unsigned int  seg_not_present : 1;
  36 };
  37
  38 static inline int modify_ldt( int func, struct modify_ldt_s *ptr,
  39                                   unsigned long count )
  40 {
  41     int res;
  42 #ifdef __PIC__
  43     __asm__ __volatile__( "pushl %%ebx\n\t"
  44                           "movl %2,%%ebx\n\t"
  45                           "int $0x80\n\t"
  46                           "popl %%ebx"
  47                           : "=a" (res)
  48                           : "0" (SYS_modify_ldt),
  49                             "r" (func),
  50                             "c" (ptr),
  51                             "d" (count) );
  52 #else
  53     __asm__ __volatile__("int $0x80"
  54                          : "=a" (res)
  55                          : "0" (SYS_modify_ldt),
  56                            "b" (func),
  57                            "c" (ptr),
  58                            "d" (count) );
  59 #endif  /* __PIC__ */
  60     if (res >= 0) return res;
  61     errno = -res;
  62     return -1;
  63 }
  64
  65 #endif  /* linux */
  66
  67 #if defined(__svr4__) || defined(_SCO_DS)
  68 #include <sys/sysi86.h>
  69 extern int sysi86(int,void*);
  70 #ifndef __sun__
  71 #include <sys/seg.h>
  72 #endif
  73 #endif
  74
  75 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
  76 #include <machine/segments.h>
  77
  78 extern int i386_get_ldt(int, union descriptor *, int);
  79 extern int i386_set_ldt(int, union descriptor *, int);
  80 #endif  /* __NetBSD__ || __FreeBSD__ || __OpenBSD__ */
  81
  82 #endif  /* __i386__ */
  83
  84 /* local copy of the LDT */
  85 struct __wine_ldt_copy wine_ldt_copy;
  86
  87
  88 /***********************************************************************
  89  *           ldt_get_entry
  90  *
  91  * Retrieve an LDT entry.
  92  */
  93 void wine_ldt_get_entry( unsigned short sel, LDT_ENTRY *entry )
  94 {
  95     int index = sel >> 3;
  96     wine_ldt_set_base(  entry, wine_ldt_copy.base[index] );
  97     wine_ldt_set_limit( entry, wine_ldt_copy.limit[index] );
  98     wine_ldt_set_flags( entry, wine_ldt_copy.flags[index] );
  99 }
 100
 101
 102 /***********************************************************************
 103  *           ldt_set_entry
 104  *
 105  * Set an LDT entry.
 106  */
 107 int wine_ldt_set_entry( unsigned short sel, const LDT_ENTRY *entry )
 108 {
 109     int ret = 0, index = sel >> 3;
 110
 111     /* Entry 0 must not be modified; its base and limit are always 0 */
 112     if (!index) return 0;
 113
 114 #ifdef __i386__
 115
 116 #ifdef linux
 117     {
 118         struct modify_ldt_s ldt_info;
 119
 120         ldt_info.entry_number    = index;
 121         ldt_info.base_addr       = (unsigned long)wine_ldt_get_base(entry);
 122         ldt_info.limit           = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
 123         ldt_info.seg_32bit       = entry->HighWord.Bits.Default_Big;
 124         ldt_info.contents        = (entry->HighWord.Bits.Type >> 2) & 3;
 125         ldt_info.read_exec_only  = !(entry->HighWord.Bits.Type & 2);
 126         ldt_info.limit_in_pages  = entry->HighWord.Bits.Granularity;
 127         ldt_info.seg_not_present = !entry->HighWord.Bits.Pres;
 128
 129         if ((ret = modify_ldt(1, &ldt_info, sizeof(ldt_info))) < 0)
 130             perror( "modify_ldt" );
 131     }
 132 #endif  /* linux */
 133
 134 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
 135     {
 136         LDT_ENTRY entry_copy = *entry;
 137         /* The kernel will only let us set LDTs with user priority level */
 138         if (entry_copy.HighWord.Bits.Pres
 139             && entry_copy.HighWord.Bits.Dpl != 3)
 140                 entry_copy.HighWord.Bits.Dpl = 3;
 141         ret = i386_set_ldt(index, (union descriptor *)&entry_copy, 1);
 142         if (ret < 0)
 143         {
 144             perror("i386_set_ldt");
 145             fprintf( stderr, "Did you reconfigure the kernel with \"options USER_LDT\"?\n" );
 146             exit(1);
 147         }
 148     }
 149 #endif  /* __NetBSD__ || __FreeBSD__ || __OpenBSD__ */
 150
 151 #if defined(__svr4__) || defined(_SCO_DS)
 152     {
 153         struct ssd ldt_mod;
 154         ldt_mod.sel  = sel;
 155         ldt_mod.bo   = (unsigned long)wine_ldt_get_base(entry);
 156         ldt_mod.ls   = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
 157         ldt_mod.acc1 = entry->HighWord.Bytes.Flags1;
 158         ldt_mod.acc2 = entry->HighWord.Bytes.Flags2 >> 4;
 159         if ((ret = sysi86(SI86DSCR, &ldt_mod)) == -1) perror("sysi86");
 160     }
 161 #endif
 162
 163 #endif  /* __i386__ */
 164
 165     if (ret >= 0)
 166     {
 167         wine_ldt_copy.base[index]  = wine_ldt_get_base(entry);
 168         wine_ldt_copy.limit[index] = wine_ldt_get_limit(entry);
 169         wine_ldt_copy.flags[index] = (entry->HighWord.Bits.Type |
 170                                  (entry->HighWord.Bits.Default_Big ? WINE_LDT_FLAGS_32BIT : 0) |
 171                                  (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED));
 172     }
 173     return ret;
 174 }