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Sweden-Number/library/ldt.c

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/*
* LDT manipulation functions
*
* Copyright 1993 Robert J. Amstadt
* Copyright 1995 Alexandre Julliard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "config.h"
#include "wine/port.h"
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include "winbase.h"
#define WINE_EXPORT_LDT_COPY
#include "wine/library.h"
#ifdef __i386__
#ifdef linux
#ifdef HAVE_SYS_SYSCALL_H
# include <sys/syscall.h>
#endif
struct modify_ldt_s
{
unsigned int entry_number;
unsigned long base_addr;
unsigned int limit;
unsigned int seg_32bit : 1;
unsigned int contents : 2;
unsigned int read_exec_only : 1;
unsigned int limit_in_pages : 1;
unsigned int seg_not_present : 1;
unsigned int useable:1;
};
#ifndef SYS_set_thread_area
#define SYS_set_thread_area 243
#endif
static inline void fill_modify_ldt_struct( struct modify_ldt_s *ptr, const LDT_ENTRY *entry )
{
ptr->base_addr = (unsigned long)wine_ldt_get_base(entry);
ptr->limit = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
ptr->seg_32bit = entry->HighWord.Bits.Default_Big;
ptr->contents = (entry->HighWord.Bits.Type >> 2) & 3;
ptr->read_exec_only = !(entry->HighWord.Bits.Type & 2);
ptr->limit_in_pages = entry->HighWord.Bits.Granularity;
ptr->seg_not_present = !entry->HighWord.Bits.Pres;
ptr->useable = entry->HighWord.Bits.Sys;
}
static inline int modify_ldt( int func, struct modify_ldt_s *ptr, unsigned long count )
{
int res;
__asm__ __volatile__( "pushl %%ebx\n\t"
"movl %2,%%ebx\n\t"
"int $0x80\n\t"
"popl %%ebx"
: "=a" (res)
: "0" (SYS_modify_ldt),
"r" (func),
"c" (ptr),
"d" (count) );
if (res >= 0) return res;
errno = -res;
return -1;
}
static inline int set_thread_area( struct modify_ldt_s *ptr )
{
int res;
__asm__ __volatile__( "pushl %%ebx\n\t"
"movl %2,%%ebx\n\t"
"int $0x80\n\t"
"popl %%ebx"
: "=a" (res)
: "0" (SYS_set_thread_area), "r" (ptr) );
if (res >= 0) return res;
errno = -res;
return -1;
}
#endif /* linux */
#if defined(__svr4__) || defined(_SCO_DS)
#include <sys/sysi86.h>
extern int sysi86(int,void*);
#ifndef __sun__
#include <sys/seg.h>
#endif
#endif
#if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
#include <machine/segments.h>
extern int i386_get_ldt(int, union descriptor *, int);
extern int i386_set_ldt(int, union descriptor *, int);
#endif /* __NetBSD__ || __FreeBSD__ || __OpenBSD__ */
#endif /* __i386__ */
/* local copy of the LDT */
struct __wine_ldt_copy wine_ldt_copy;
static const LDT_ENTRY null_entry; /* all-zeros, used to clear LDT entries */
#define LDT_SIZE 8192
/* empty function for default locks */
static void nop(void) { }
static void (*lock_ldt)(void) = nop;
static void (*unlock_ldt)(void) = nop;
static inline int is_gdt_sel( unsigned short sel ) { return !(sel & 4); }
/***********************************************************************
* wine_ldt_init_locking
*
* Set the LDT locking/unlocking functions.
*/
void wine_ldt_init_locking( void (*lock_func)(void), void (*unlock_func)(void) )
{
lock_ldt = lock_func;
unlock_ldt = unlock_func;
}
/***********************************************************************
* wine_ldt_get_entry
*
* Retrieve an LDT entry. Return a null entry if selector is not allocated.
*/
void wine_ldt_get_entry( unsigned short sel, LDT_ENTRY *entry )
{
int index = sel >> 3;
if (is_gdt_sel(sel))
{
*entry = null_entry;
return;
}
lock_ldt();
if (wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED)
{
wine_ldt_set_base( entry, wine_ldt_copy.base[index] );
wine_ldt_set_limit( entry, wine_ldt_copy.limit[index] );
wine_ldt_set_flags( entry, wine_ldt_copy.flags[index] );
}
else *entry = null_entry;
unlock_ldt();
}
/***********************************************************************
* internal_set_entry
*
* Set an LDT entry, without locking. For internal use only.
*/
static int internal_set_entry( unsigned short sel, const LDT_ENTRY *entry )
{
int ret = 0, index = sel >> 3;
if (index < WINE_LDT_FIRST_ENTRY) return 0; /* cannot modify reserved entries */
#ifdef __i386__
#ifdef linux
{
struct modify_ldt_s ldt_info;
ldt_info.entry_number = index;
fill_modify_ldt_struct( &ldt_info, entry );
if ((ret = modify_ldt(0x11, &ldt_info, sizeof(ldt_info))) < 0)
perror( "modify_ldt" );
}
#endif /* linux */
#if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
{
LDT_ENTRY entry_copy = *entry;
/* The kernel will only let us set LDTs with user priority level */
if (entry_copy.HighWord.Bits.Pres
&& entry_copy.HighWord.Bits.Dpl != 3)
entry_copy.HighWord.Bits.Dpl = 3;
ret = i386_set_ldt(index, (union descriptor *)&entry_copy, 1);
if (ret < 0)
{
perror("i386_set_ldt");
fprintf( stderr, "Did you reconfigure the kernel with \"options USER_LDT\"?\n" );
exit(1);
}
}
#endif /* __NetBSD__ || __FreeBSD__ || __OpenBSD__ */
#if defined(__svr4__) || defined(_SCO_DS)
{
struct ssd ldt_mod;
ldt_mod.sel = sel;
ldt_mod.bo = (unsigned long)wine_ldt_get_base(entry);
ldt_mod.ls = entry->LimitLow | (entry->HighWord.Bits.LimitHi << 16);
ldt_mod.acc1 = entry->HighWord.Bytes.Flags1;
ldt_mod.acc2 = entry->HighWord.Bytes.Flags2 >> 4;
if ((ret = sysi86(SI86DSCR, &ldt_mod)) == -1) perror("sysi86");
}
#endif
#endif /* __i386__ */
if (ret >= 0)
{
wine_ldt_copy.base[index] = wine_ldt_get_base(entry);
wine_ldt_copy.limit[index] = wine_ldt_get_limit(entry);
wine_ldt_copy.flags[index] = (entry->HighWord.Bits.Type |
(entry->HighWord.Bits.Default_Big ? WINE_LDT_FLAGS_32BIT : 0) |
(wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_ALLOCATED));
}
return ret;
}
/***********************************************************************
* wine_ldt_set_entry
*
* Set an LDT entry.
*/
int wine_ldt_set_entry( unsigned short sel, const LDT_ENTRY *entry )
{
int ret;
lock_ldt();
ret = internal_set_entry( sel, entry );
unlock_ldt();
return ret;
}
/***********************************************************************
* wine_ldt_get_ptr
*
* Convert a segment:offset pair to a linear pointer.
* Note: we don't lock the LDT since this has to be fast.
*/
void *wine_ldt_get_ptr( unsigned short sel, unsigned int offset )
{
int index;
if (is_gdt_sel(sel)) /* GDT selector */
return (void *)offset;
if ((index = (sel >> 3)) < WINE_LDT_FIRST_ENTRY) /* system selector */
return (void *)offset;
if (!(wine_ldt_copy.flags[index] & WINE_LDT_FLAGS_32BIT)) offset &= 0xffff;
return (char *)wine_ldt_copy.base[index] + offset;
}
/***********************************************************************
* wine_ldt_alloc_entries
*
* Allocate a number of consecutive ldt entries, without setting the LDT contents.
* Return a selector for the first entry.
*/
unsigned short wine_ldt_alloc_entries( int count )
{
int i, index, size = 0;
if (count <= 0) return 0;
lock_ldt();
for (i = WINE_LDT_FIRST_ENTRY; i < LDT_SIZE; i++)
{
if (wine_ldt_copy.flags[i] & WINE_LDT_FLAGS_ALLOCATED) size = 0;
else if (++size >= count) /* found a large enough block */
{
index = i - size + 1;
/* mark selectors as allocated */
for (i = 0; i < count; i++) wine_ldt_copy.flags[index + i] |= WINE_LDT_FLAGS_ALLOCATED;
unlock_ldt();
return (index << 3) | 7;
}
}
unlock_ldt();
return 0;
}
/***********************************************************************
* wine_ldt_realloc_entries
*
* Reallocate a number of consecutive ldt entries, without changing the LDT contents.
* Return a selector for the first entry.
*/
unsigned short wine_ldt_realloc_entries( unsigned short sel, int oldcount, int newcount )
{
int i;
if (oldcount < newcount) /* we need to add selectors */
{
int index = sel >> 3;
lock_ldt();
/* check if the next selectors are free */
if (index + newcount > LDT_SIZE) i = oldcount;
else
for (i = oldcount; i < newcount; i++)
if (wine_ldt_copy.flags[index+i] & WINE_LDT_FLAGS_ALLOCATED) break;
if (i < newcount) /* they are not free */
{
wine_ldt_free_entries( sel, oldcount );
sel = wine_ldt_alloc_entries( newcount );
}
else /* mark the selectors as allocated */
{
for (i = oldcount; i < newcount; i++)
wine_ldt_copy.flags[index+i] |= WINE_LDT_FLAGS_ALLOCATED;
}
unlock_ldt();
}
else if (oldcount > newcount) /* we need to remove selectors */
{
wine_ldt_free_entries( sel + (newcount << 3), newcount - oldcount );
}
return sel;
}
/***********************************************************************
* wine_ldt_free_entries
*
* Free a number of consecutive ldt entries and clear their contents.
*/
void wine_ldt_free_entries( unsigned short sel, int count )
{
int index;
lock_ldt();
for (index = sel >> 3; count > 0; count--, index++)
{
internal_set_entry( sel, &null_entry );
wine_ldt_copy.flags[index] = 0;
}
unlock_ldt();
}
#ifdef __i386__
static int fs_gdt_index = -1; /* GDT index for %fs, or 0 if GDT not supported on this kernel */
/***********************************************************************
* wine_ldt_alloc_fs
*
* Allocate an LDT entry for a %fs selector, reusing a global
* GDT selector if possible. Return the selector value.
*/
unsigned short wine_ldt_alloc_fs(void)
{
if (fs_gdt_index == -1)
{
#ifdef __linux__
struct modify_ldt_s ldt_info;
int ret;
ldt_info.entry_number = -1;
fill_modify_ldt_struct( &ldt_info, &null_entry );
if ((ret = set_thread_area( &ldt_info ) < 0))
{
fs_gdt_index = 0; /* don't try it again */
if (errno != ENOSYS) perror( "set_thread_area" );
}
else fs_gdt_index = ldt_info.entry_number;
#endif /* __linux__ */
}
if (fs_gdt_index > 0) return (fs_gdt_index << 3) | 3;
return wine_ldt_alloc_entries( 1 );
}
/***********************************************************************
* wine_ldt_init_fs
*
* Initialize the entry for the %fs selector of the current thread, and
* set the thread %fs register.
*
* Note: this runs in the context of the new thread, so cannot acquire locks.
*/
void wine_ldt_init_fs( unsigned short sel, const LDT_ENTRY *entry )
{
if (is_gdt_sel(sel))
{
#ifdef __linux__
struct modify_ldt_s ldt_info;
int ret;
ldt_info.entry_number = sel >> 3;
assert( ldt_info.entry_number == fs_gdt_index );
fill_modify_ldt_struct( &ldt_info, entry );
if ((ret = set_thread_area( &ldt_info ) < 0)) perror( "set_thread_area" );
#endif /* __linux__ */
}
else /* LDT selector */
{
internal_set_entry( sel, entry );
}
wine_set_fs( sel );
}
/***********************************************************************
* wine_ldt_free_fs
*
* Free a %fs selector returned by wine_ldt_alloc_fs.
*/
void wine_ldt_free_fs( unsigned short sel )
{
if (is_gdt_sel(sel)) return; /* nothing to do */
if (!((wine_get_fs() ^ sel) & ~3))
{
/* FIXME: if freeing current %fs we cannot acquire locks */
wine_set_fs( 0 );
internal_set_entry( sel, &null_entry );
wine_ldt_copy.flags[sel >> 3] = 0;
}
else wine_ldt_free_entries( sel, 1 );
}
/***********************************************************************
* selector access functions
*/
# ifndef _MSC_VER
/* Nothing needs to be done for MS C, it will do with inline versions from the winnt.h */
__ASM_GLOBAL_FUNC( wine_get_cs, "movw %cs,%ax\n\tret" )
__ASM_GLOBAL_FUNC( wine_get_ds, "movw %ds,%ax\n\tret" )
__ASM_GLOBAL_FUNC( wine_get_es, "movw %es,%ax\n\tret" )
__ASM_GLOBAL_FUNC( wine_get_fs, "movw %fs,%ax\n\tret" )
__ASM_GLOBAL_FUNC( wine_get_gs, "movw %gs,%ax\n\tret" )
__ASM_GLOBAL_FUNC( wine_get_ss, "movw %ss,%ax\n\tret" )
__ASM_GLOBAL_FUNC( wine_set_fs, "movl 4(%esp),%eax\n\tmovw %ax,%fs\n\tret" )
__ASM_GLOBAL_FUNC( wine_set_gs, "movl 4(%esp),%eax\n\tmovw %ax,%gs\n\tret" )
# endif /* defined(_MSC_VER) */
#endif /* __i386__ */
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