266 lines
8.3 KiB
C
266 lines
8.3 KiB
C
/*
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* LDT manipulation functions
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*
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* Copyright 1993 Robert J. Amstadt
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* Copyright 1995 Alexandre Julliard
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include "ldt.h"
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#include "stddebug.h"
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#include "debug.h"
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#ifdef linux
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#include <syscall.h>
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struct modify_ldt_s
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{
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unsigned int entry_number;
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unsigned long base_addr;
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unsigned int limit;
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unsigned int seg_32bit : 1;
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unsigned int contents : 2;
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unsigned int read_exec_only : 1;
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unsigned int limit_in_pages : 1;
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unsigned int seg_not_present : 1;
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};
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static __inline__ _syscall3(int, modify_ldt, int, func, void *, ptr,
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unsigned long, bytecount);
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#endif /* linux */
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#if defined(__svr4__) || defined(_SCO_DS)
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#include <sys/sysi86.h>
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#include <sys/seg.h>
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#endif
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#if defined(__NetBSD__) || defined(__FreeBSD__)
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#include <machine/segments.h>
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extern int i386_get_ldt(int, union descriptor *, int);
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extern int i386_set_ldt(int, union descriptor *, int);
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#endif /* __NetBSD__ || __FreeBSD__ */
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ldt_copy_entry ldt_copy[LDT_SIZE];
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unsigned char ldt_flags_copy[LDT_SIZE];
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/***********************************************************************
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* LDT_BytesToEntry
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*
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* Convert the raw bytes of the descriptor to an ldt_entry structure.
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*/
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void LDT_BytesToEntry( const unsigned long *buffer, ldt_entry *content )
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{
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content->base = (*buffer >> 16) & 0x0000ffff;
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content->limit = *buffer & 0x0000ffff;
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buffer++;
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content->base |= (*buffer & 0xff000000) | ((*buffer << 16) & 0x00ff0000);
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content->limit |= (*buffer & 0x000f0000);
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content->type = (*buffer >> 10) & 3;
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content->seg_32bit = (*buffer & 0x00400000) != 0;
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content->read_only = (*buffer & 0x00000200) == 0;
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content->limit_in_pages = (*buffer & 0x00800000) != 0;
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}
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/***********************************************************************
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* LDT_EntryToBytes
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*
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* Convert an ldt_entry structure to the raw bytes of the descriptor.
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*/
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void LDT_EntryToBytes( unsigned long *buffer, const ldt_entry *content )
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{
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*buffer++ = ((content->base & 0x0000ffff) << 16) |
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(content->limit & 0x0ffff);
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*buffer = (content->base & 0xff000000) |
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((content->base & 0x00ff0000)>>16) |
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(content->limit & 0xf0000) |
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(content->type << 10) |
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((content->read_only == 0) << 9) |
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((content->seg_32bit != 0) << 22) |
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((content->limit_in_pages != 0) << 23) |
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0xf000;
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}
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/***********************************************************************
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* LDT_GetEntry
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*
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* Retrieve an LDT entry.
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*/
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int LDT_GetEntry( int entry, ldt_entry *content )
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{
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int ret = 0;
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content->base = ldt_copy[entry].base;
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content->limit = ldt_copy[entry].limit;
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content->type = (ldt_flags_copy[entry] & LDT_FLAGS_TYPE);
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content->seg_32bit = (ldt_flags_copy[entry] & LDT_FLAGS_32BIT) != 0;
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content->read_only = (ldt_flags_copy[entry] & LDT_FLAGS_READONLY) !=0;
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content->limit_in_pages = (ldt_flags_copy[entry] & LDT_FLAGS_BIG) !=0;
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if (content->limit_in_pages) content->limit >>= 12;
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return ret;
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}
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/***********************************************************************
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* LDT_SetEntry
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*
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* Set an LDT entry.
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*/
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int LDT_SetEntry( int entry, const ldt_entry *content )
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{
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int ret = 0;
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dprintf_ldt(stddeb,
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"LDT_SetEntry: entry=%04x base=%08lx limit=%05lx %s %d-bit flags=%c%c%c\n",
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entry, content->base, content->limit,
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content->limit_in_pages ? "pages" : "bytes",
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content->seg_32bit ? 32 : 16,
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content->read_only && (content->type & SEGMENT_CODE) ? '-' : 'r',
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content->read_only || (content->type & SEGMENT_CODE) ? '-' : 'w',
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(content->type & SEGMENT_CODE) ? 'x' : '-' );
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/* Entry 0 must not be modified; its base and limit are always 0 */
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if (!entry) return 0;
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#ifdef linux
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if (!__winelib)
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{
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struct modify_ldt_s ldt_info;
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ldt_info.entry_number = entry;
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ldt_info.base_addr = content->base;
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ldt_info.limit = content->limit;
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ldt_info.seg_32bit = content->seg_32bit != 0;
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ldt_info.contents = content->type;
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ldt_info.read_exec_only = content->read_only != 0;
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ldt_info.limit_in_pages = content->limit_in_pages != 0;
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ldt_info.seg_not_present = 0;
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/* Make sure the info will be accepted by the kernel */
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/* This is ugly, but what can I do? */
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if (content->type == SEGMENT_STACK)
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{
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/* FIXME */
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}
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else
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{
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if (ldt_info.base_addr >= 0xc0000000)
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{
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fprintf( stderr, "LDT_SetEntry: invalid base addr %08lx\n",
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ldt_info.base_addr );
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return -1;
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}
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if (content->limit_in_pages)
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{
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if ((ldt_info.limit << 12) + 0xfff >
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0xc0000000 - ldt_info.base_addr)
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ldt_info.limit = (0xc0000000 - 0xfff - ldt_info.base_addr) >> 12;
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}
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else
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{
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if (ldt_info.limit > 0xc0000000 - ldt_info.base_addr)
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ldt_info.limit = 0xc0000000 - ldt_info.base_addr;
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}
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}
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if ((ret = modify_ldt(1, &ldt_info, sizeof(ldt_info))) < 0)
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perror( "modify_ldt" );
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}
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#endif /* linux */
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#if defined(__NetBSD__) || defined(__FreeBSD__)
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if (!__winelib)
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{
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long d[2];
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LDT_EntryToBytes( d, content );
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ret = i386_set_ldt(entry, (union descriptor *)d, 1);
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if (ret < 0)
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{
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perror("i386_set_ldt");
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fprintf(stderr,
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"Did you reconfigure the kernel with \"options USER_LDT\"?\n");
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exit(1);
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}
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}
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#endif /* __NetBSD__ || __FreeBSD__ */
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#if defined(__svr4__) || defined(_SCO_DS)
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if (!__winelib)
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{
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struct ssd ldt_mod;
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int i;
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ldt_mod.sel = ENTRY_TO_SELECTOR(entry) | 4;
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ldt_mod.bo = content->base;
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ldt_mod.ls = content->limit;
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i = ((content->limit & 0xf0000) |
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(content->type << 10) |
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(((content->read_only != 0) ^ 1) << 9) |
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((content->seg_32bit != 0) << 22) |
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((content->limit_in_pages != 0)<< 23) |
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(1<<15) |
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0x7000);
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ldt_mod.acc1 = (i & 0xff00) >> 8;
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ldt_mod.acc2 = (i & 0xf00000) >> 20;
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if (content->base == 0)
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{
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ldt_mod.acc1 = 0;
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ldt_mod.acc2 = 0;
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}
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if ((ret = sysi86(SI86DSCR, &ldt_mod)) == -1) perror("sysi86");
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}
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#endif
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if (ret < 0) return ret;
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ldt_copy[entry].base = content->base;
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if (!content->limit_in_pages) ldt_copy[entry].limit = content->limit;
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else ldt_copy[entry].limit = (content->limit << 12) | 0x0fff;
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ldt_flags_copy[entry] = (content->type & LDT_FLAGS_TYPE) |
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(content->read_only ? LDT_FLAGS_READONLY : 0) |
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(content->seg_32bit ? LDT_FLAGS_32BIT : 0) |
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(content->limit_in_pages ? LDT_FLAGS_BIG : 0) |
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(ldt_flags_copy[entry] & LDT_FLAGS_ALLOCATED);
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return ret;
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}
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/***********************************************************************
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* LDT_Print
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*
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* Print the content of the LDT on stdout.
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*/
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void LDT_Print( int start, int length )
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{
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int i;
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char flags[3];
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if (length == -1) length = LDT_SIZE - start;
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for (i = start; i < start + length; i++)
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{
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if (!ldt_copy[i].base && !ldt_copy[i].limit) continue; /* Free entry */
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if ((ldt_flags_copy[i] & LDT_FLAGS_TYPE) == SEGMENT_CODE)
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{
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flags[0] = (ldt_flags_copy[i] & LDT_FLAGS_EXECONLY) ? '-' : 'r';
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flags[1] = '-';
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flags[2] = 'x';
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}
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else
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{
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flags[0] = 'r';
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flags[1] = (ldt_flags_copy[i] & LDT_FLAGS_READONLY) ? '-' : 'w';
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flags[2] = '-';
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}
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printf("%04x: sel=%04x base=%08lx limit=%08lx %d-bit %c%c%c\n",
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i, ENTRY_TO_SELECTOR(i),
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ldt_copy[i].base, ldt_copy[i].limit,
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ldt_flags_copy[i] & LDT_FLAGS_32BIT ? 32 : 16,
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flags[0], flags[1], flags[2] );
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}
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}
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