loader/ldtlib.c

   1 static char RCSId[] = "$Id: ldtlib.c,v 1.2 1993/07/04 04:04:21 root Exp root $";
   2 static char Copyright[] = "Copyright  Robert J. Amstadt, 1993";
   3
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <errno.h>
   7 #ifdef linux
   8 #include <linux/unistd.h>
   9 #include <linux/head.h>
  10 #include <linux/ldt.h>
  11
  12 _syscall3(int, modify_ldt, int, func, void *, ptr, unsigned long, bytecount)
  13 #endif
  14 #if defined(__NetBSD__) || defined(__FreeBSD__)
  15 #include <machine/segments.h>
  16
  17 extern int i386_get_ldt(int, union descriptor *, int);
  18 extern int i386_set_ldt(int, union descriptor *, int);
  19
  20 struct segment_descriptor *
  21 make_sd(unsigned base, unsigned limit, int contents, int read_exec_only, int seg32, int inpgs)
  22 {
  23         static long d[2];
  24
  25         d[0] = ((base & 0x0000ffff) << 16) |
  26                 (limit & 0x0ffff);
  27         d[1] = (base & 0xff000000) |
  28                 ((base & 0x00ff0000)>>16) |
  29                         (limit & 0xf0000) |
  30                                 (contents << 10) |
  31                                         ((read_exec_only ^ 1) << 9) |
  32                                                 (seg32 << 22) |
  33                                                         (inpgs << 23) |
  34                                                                 0xf000;
  35
  36         return ((struct segment_descriptor *)d);
  37 }
  38 #endif
  39
  40 int
  41 get_ldt(void *buffer)
  42 {
  43 #ifdef linux
  44     return modify_ldt(0, buffer, 32 * sizeof(struct modify_ldt_ldt_s));
  45 #endif
  46 #if defined(__NetBSD__) || defined(__FreeBSD__)
  47     return i386_get_ldt(0, (union descriptor *)buffer, 32);
  48 #endif
  49 }
  50
  51 int
  52 set_ldt_entry(int entry, unsigned long base, unsigned int limit,
  53               int seg_32bit_flag, int contents, int read_only_flag,
  54               int limit_in_pages_flag)
  55 {
  56 #ifdef linux
  57     struct modify_ldt_ldt_s ldt_info;
  58
  59     ldt_info.entry_number   = entry;
  60     ldt_info.base_addr      = base;
  61     ldt_info.limit          = limit;
  62     ldt_info.seg_32bit      = seg_32bit_flag;
  63     ldt_info.contents       = contents;
  64     ldt_info.read_exec_only = read_only_flag;
  65     ldt_info.limit_in_pages = limit_in_pages_flag;
  66
  67     return modify_ldt(1, &ldt_info, sizeof(ldt_info));
  68 #endif
  69 #if defined(__NetBSD__) || defined(__FreeBSD__)
  70     struct segment_descriptor *sd;
  71     int ret;
  72
  73 #ifdef DEBUG_LDT
  74     printf("set_ldt_entry: entry=%x base=%x limit=%x%s %s-bit contents=%d %s\n",
  75            entry, base, limit, limit_in_pages_flag?"-pages":"",
  76            seg_32bit_flag?"32":"16",
  77            contents, read_only_flag?"read-only":"");
  78 #endif
  79
  80     sd = make_sd(base, limit, contents, read_only_flag, seg_32bit_flag, limit_in_pages_flag);
  81     ret = i386_set_ldt(entry, (union descriptor *)sd, 1);
  82     if (ret < 0)
  83             perror("i386_set_ldt");
  84
  85     return ret;
  86
  87 #endif
  88 }