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0
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1 /* Code to do an unexec for Sun O/S 4.1 for a temacs linked -Bdynamic.
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2 Copyright (C) 1992, 1993 Free Software Foundation, Inc.
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3
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4 This file is part of XEmacs.
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5
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6 XEmacs is free software; you can redistribute it and/or modify it
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7 under the terms of the GNU General Public License as published by the
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8 Free Software Foundation; either version 2, or (at your option) any
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9 later version.
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10
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11 XEmacs is distributed in the hope that it will be useful, but WITHOUT
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12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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14 for more details.
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15
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16 You should have received a copy of the GNU General Public License
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17 along with XEmacs; see the file COPYING. If not, write to
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18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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19 Boston, MA 02111-1307, USA. */
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20
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21 /* Synched up with: Not synched with FSF. */
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22
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23 /*
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24 Created 29-Oct-92 by Harlan Sexton
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25 Tweaked 06-Aug-93 by Dean Michaels to work with sun3.
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26 */
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27
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28 /********************** Included .h Files **************************/
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29
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30 #include <config.h>
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31
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32 /* I don't understand this, but it's necessary to get some slots in struct exec
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33 from /usr/include/sys/exec.h when running LCC in strict ANSI mode. We don't
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34 need this in K&R mode...
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35 */
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36 #if defined(__lucid) && defined(__sparc) && !defined(sun)
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37 # define sun 1
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38 #endif
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39
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40 #include <stdarg.h>
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41 #include <sys/param.h>
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42 #include <sys/mman.h>
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43 #include <sys/file.h>
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44 #include <sys/stat.h>
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45 #include <sys/types.h>
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46 #include <string.h>
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47 #include <stdio.h>
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48 #include <a.out.h>
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49 #include <unistd.h>
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50 #include <ctype.h>
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51 #include <stab.h>
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52 #include <sys/dir.h>
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53 #include <link.h>
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54
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55 /********************** Macros *************************************/
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56
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57 #define SYS_ERR \
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58 ((errno > 0)?((errno < sys_nerr)?(sys_errlist[errno]):\
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59 "unknown system error"): "unknown error")
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60
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61 #define MASK_UP(x,p_of_two) \
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62 ((((unsigned long) (x)) + ((p_of_two) - 1)) & (~((p_of_two) - 1)))
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63
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64 #define MASK_DOWN(x,p_of_two) (((unsigned long) (x)) & (~((p_of_two) - 1)))
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65
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66 #ifndef mc68020
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67 #define relocation_info reloc_info_sparc
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68 #endif
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69
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70 /********************** Typedefs and Structs ***********************/
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71
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72 struct translation_struct
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73 {
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74 long txtaddr;
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75 long txtoff;
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76 long dataddr;
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77 long datoff;
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78 long bssaddr;
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79 };
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80
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81 /********************** Function Prototypes/Declarations ***********/
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82
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83 static void unexec_error (CONST char *m, int use_errno, ...);
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84 static int unexec_open (char *filename, int flag, int mode);
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85 static caddr_t unexec_mmap (int fd, size_t len, int prot, int flags);
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86 static long unexec_seek (int fd, long position);
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87 static void unexec_read (int fd, long position, char *buf, int bytes);
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88 static void unexec_write (int fd, long position, char *buf, int bytes);
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89 static void unexec_pad (int fd, int bytes);
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90 static void unexec_fstat (int fd, struct stat *statptr);
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91 static void unexec_fchmod (int fd, int mode);
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92 static long unexec_addr_to_offset (long addr, struct translation_struct *ts);
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93 static void copy_relocation_site (struct relocation_info *ri,
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94 caddr_t from_base_addr,
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95 caddr_t to_base_addr,
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96 struct translation_struct *ts);
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97 static void reset_symtab (struct nlist *start, struct nlist *end,
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98 char *strtab, long edata_value, long end_value,
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99 int ld_so_table, int shlib_image);
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100 int run_time_remap (char *dummy);
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101
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102 /********************** Variables **********************************/
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103
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104 /* for reporting error messages from system calls */
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105 extern int sys_nerr;
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106 extern char *sys_errlist[];
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107 extern int errno;
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108 extern int _DYNAMIC;
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109 extern char **environ;
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110
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111 static unsigned long mprotect_bottom_addr;
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112 static unsigned long mprotect_top_addr;
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113
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114 static unsigned long sbrk_of_0_at_unexec;
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115
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116 /*******************************************************************/
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117
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118 static void
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119 unexec_error (CONST char *fmt, int use_errno, ...)
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120 {
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121 CONST char *err_msg = SYS_ERR;
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122 va_list args;
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123
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124 fprintf (stderr, "unexec - ");
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125 va_start (args, use_errno);
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126 vfprintf (stderr, fmt, args);
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127 va_end (args);
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128
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129 if (use_errno)
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130 fprintf (stderr, ": %s", err_msg);
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131 fprintf (stderr, "\n");
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132 exit (1);
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133 return;
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134 }
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135
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136 static int
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137 unexec_open (char *filename, int flag, int mode)
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138 {
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139 int fd;
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140
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141 errno = 0;
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142
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143 fd = open (filename, flag, mode);
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144
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145 if (fd < 0)
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146 unexec_error ("Failure opening file %s", 1, (void *) filename, 0, 0);
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147 return fd;
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148 }
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149
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150 static caddr_t
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151 unexec_mmap (int fd, size_t len, int prot, int flags)
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152 {
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153 caddr_t return_val;
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154
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155 unexec_seek (fd, 0);
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156 errno = 0;
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157 return_val = mmap (0, len, prot, flags, fd, 0);
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158
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159 if (return_val == (caddr_t) -1)
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160 unexec_error ("Failure mmap'ing file", 1, 0, 0, 0);
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161 return return_val;
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162 }
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163
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164
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165 static long
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166 unexec_seek (int fd, long position)
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167 {
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168 long seek_value;
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169
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170 if (fd <= 0)
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171 unexec_error ("No file open in which to seek", 0, 0, 0, 0);
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172
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173 errno = 0;
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174
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175 if (position < 0)
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176 seek_value = (long) lseek (fd, 0, L_INCR);
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177 else
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178 seek_value = (long) lseek (fd, position, L_SET);
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179
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180 if (seek_value < 0)
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181 unexec_error ("Failed to do a seek to 0x%x in %s", 1,
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182 (char *) position, "unexec() output file", 0);
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183
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184 return seek_value;
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185 }
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186
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187 static void
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188 unexec_read (int fd, long position, char *buf, int bytes)
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189 {
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190 int n_read;
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191 int remains = bytes;
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192 position = unexec_seek (fd, position);
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193
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194 if (bytes < 0)
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195 unexec_error ("Attempted read of %d bytes", 0, (char *) bytes, 0, 0);
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196
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197 errno = 0;
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198
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199 while (remains > 0)
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200 {
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201 n_read = read (fd, buf, remains);
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202 if (n_read <= 0)
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203 unexec_error ("Read failed for 0x%x bytes at offset 0x%x in %s",
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204 1, (char *) bytes, (char *) position,
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205 "unexec() output file");
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206 buf += n_read;
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207 remains -= n_read;
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208 }
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209
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210 return;
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211 }
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212
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213 static void
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214 unexec_write (int fd, long position, char *buf, int bytes)
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215 {
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216 int n_written;
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217 int remains = bytes;
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218 position = unexec_seek (fd, position);
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219
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220 if (bytes < 0)
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221 unexec_error ("Attempted write of %d bytes in %s",
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222 0, (char *) bytes, "unexec() output file", 0);
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223
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224 errno = 0;
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225
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226 while (remains > 0)
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227 {
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228 n_written = write (fd, buf, remains);
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229 if (n_written <= 0)
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230 unexec_error ("Write failed for 0x%x bytes at offset 0x%x in %s",
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231 1, (char *) bytes, (char *) position,
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232 "unexec() output file");
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233 buf += n_written;
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234 remains -= n_written;
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235 }
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236
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237 return;
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238 }
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239
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240 static void
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241 unexec_pad (int fd, int bytes)
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242 {
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243 if (bytes > 0)
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244 {
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245 char buf[1024];
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246 int remaining = bytes;
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247
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248 memset (buf, 0, sizeof (buf));
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249
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250 while (remaining > 0)
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251 {
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252 int this_write = (remaining > sizeof(buf))?sizeof(buf):remaining;
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253 unexec_write (fd, -1, buf, this_write);
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254 remaining -= this_write;
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255 }
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256 }
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257 }
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258
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259 static void
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260 unexec_fstat (int fd, struct stat *statptr)
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261 {
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262 errno = 0;
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263 if (-1 == fstat (fd, statptr))
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264 unexec_error ("fstat() failed for descriptor %d", 1, (char *) fd, 0, 0);
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265 return;
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266 }
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267
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268 static void
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269 unexec_fchmod (int fd, int mode)
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270 {
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271 errno = 0;
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272 if (-1 == fchmod (fd, mode))
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273 unexec_error ("fchmod() failed for descriptor %d", 1, (char *) fd, 0, 0);
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274 return;
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275 }
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276
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277 static long
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278 unexec_addr_to_offset (long addr, struct translation_struct *ts)
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279
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280 {
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281 if ((addr < ts->txtaddr) || (addr >= ts->bssaddr))
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282 unexec_error ("bad address 0x%x to addr_to_offset()",
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283 0, (char *) addr, 0, 0);
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284 if (addr >= ts->dataddr)
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285 return ((long) ((addr - ts->dataddr) + ts->datoff));
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286 else
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287 return ((long) ((addr - ts->txtaddr) + ts->txtoff));
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288 }
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289
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290
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291 /*
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292 * "LD.SO" DATA AND SYMBOL TABLE OPERATIONS
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293 */
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294
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295 static void
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296 copy_relocation_site (struct relocation_info *ri,
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297 caddr_t from_base_addr,
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298 caddr_t to_base_addr,
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299 struct translation_struct *ts)
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300 {
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301 long offset = unexec_addr_to_offset (ri->r_address, ts);
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302 caddr_t from = from_base_addr + offset;
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303 caddr_t to = to_base_addr + offset;
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304
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305 #ifdef mc68020
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306 #define r_type r_length
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307 #endif /* mc68020 */
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308 switch (ri->r_type)
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309 {
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310 #ifdef mc68020
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311 case 0:
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312 *((char *) to) = *((char *) from);
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313 break;
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314 case 1:
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315 *((short *) to) = *((short *) from);
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316 break;
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317 case 2:
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318 *((long *) to) = *((long *) from);
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319 break;
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320 #else /* !mc68020 */
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321 case RELOC_8:
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322 case RELOC_DISP8:
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323 *((char *) to) = *((char *) from);
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324 break;
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325 case RELOC_16:
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326 case RELOC_DISP16:
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327 *((short *) to) = *((short *) from);
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328 break;
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329 case RELOC_LO10:
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330 case RELOC_13:
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331 case RELOC_22:
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332 case RELOC_HI22:
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333 case RELOC_WDISP22:
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334 case RELOC_WDISP30:
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335 case RELOC_32:
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336 case RELOC_DISP32:
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337 case RELOC_GLOB_DAT:
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338 *((long *) to) = *((long *) from);
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339 break;
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340 case RELOC_JMP_SLOT:
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341 {
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342 long *target = (long *) to;
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343 long *source = (long *) from;
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344 *target = *source;
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345 target++;
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346 source++;
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347 *target = *source;
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348 target++;
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349 source++;
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350 *target = *source;
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351 }
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352 break;
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353 #endif /* !mc68020 */
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354 default:
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355 unexec_error ("unknown reloc type %d seen during unexec()",
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356 0, (char *) ri->r_type, 0, 0);
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357 break;
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358 }
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359 return;
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360 }
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361
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362 static void
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363 reset_symtab (struct nlist *start, struct nlist *end, char *strtab,
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364 long edata_value, long end_value, int ld_so_table,
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365 int shlib_image)
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366 {
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367 struct nlist *tmp = start;
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368 int found_edata = 0;
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369 int found_end = 0;
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370
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371 while (tmp < end)
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372 {
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373 int type = tmp->n_type;
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374 int named = (ld_so_table)?1:(tmp->n_un.n_strx);
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375
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376 if ((type == (N_UNDF | N_EXT)) &&
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377 (tmp->n_value != 0))
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378 unexec_error ("unexec'ing image has COMMON symbols in it -- we quit!",
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379 0, 0, 0, 0);
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380
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381 if (!(type & N_STAB))
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382 {
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383 if (!found_edata &&
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384 (type == (N_EXT | N_DATA)) &&
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385 named &&
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386 !strcmp ("_edata", strtab + tmp->n_un.n_strx))
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387 {
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388 tmp->n_value = edata_value;
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389 found_edata = 1;
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390 }
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391
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392
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393 if ((type & N_TYPE) == N_BSS)
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394 {
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395 if (!found_end &&
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396 (type == (N_EXT | N_BSS)) &&
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397 named &&
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398 !strcmp ("_end", strtab + tmp->n_un.n_strx))
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399 {
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400 tmp->n_value = end_value;
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401 found_end = 1;
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402 }
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403 else if (type & N_EXT)
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404 tmp->n_type = N_DATA | N_EXT;
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405 else
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406 tmp->n_type = N_DATA;
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407 }
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408
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409 /* the way things are being handled here, having sbrk() in the
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410 image is fatal for an image linked with shared lib's (although
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411 the code could be modified to support it), but this should
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412 never happen anyway */
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413 if (shlib_image &&
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414 (type == (N_EXT | N_TEXT)) &&
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415 named &&
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416 !strcmp ("_sbrk", strtab + tmp->n_un.n_strx))
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417 unexec_error ("unexec'd shlib image has sbrk() in it -- we quit!",
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418 0, 0, 0, 0);
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419 }
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420
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421 tmp++;
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422 }
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423 }
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424
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425 extern int getpagesize (void);
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426
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427 /*
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428 * EXPORTED FUNCTIONS
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429 */
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430
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431 /* this has to be a global variable to prevent the optimizers from
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432 * assuming that it can not be 0.
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433 */
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434 static void *dynamic_addr = (void *) &_DYNAMIC;
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435
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436 int
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437 unexec (char *new_name, char *old_name,
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438 unsigned int emacs_edata, unsigned int dummy1, unsigned int dummy2)
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439 {
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440 /* ld.so data */
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441 struct link_dynamic *ld = 0;
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442 struct link_dynamic_2 *ld2 = 0;
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443 /* old and new state */
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444 int old_fd;
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445 int new_fd;
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446 caddr_t old_base_addr;
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447 caddr_t new_base_addr;
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448 struct exec old_hdr;
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449 struct exec new_hdr;
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450 struct stat old_buf;
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451 struct stat new_buf;
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452 /* some process specific "constants" */
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453 unsigned long n_pagsiz;
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454 long page_size = getpagesize ();
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455 caddr_t plt_end;
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456 caddr_t current_break = (caddr_t) sbrk (0);
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457
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458 if (!page_size)
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459 unexec_error ("unexec() failed because we can't get the size of a page!",
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460 0, 0, 0, 0);
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461
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462 /* see if this is a -Bdynamic image -- if so, find ld.so structures */
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463 if (dynamic_addr)
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464 {
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465 ld = (struct link_dynamic *) dynamic_addr;
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466 ld2 = ld->ld_un.ld_2;
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467 if (ld->ld_version < 2)
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468 unexec_error ("%s linked with obsolete version of ld -- we quit!",
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469 0, old_name, 0, 0);
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470 }
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471
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472 /* open the old and new files, figuring out how big the old one is
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473 so that we can map it in */
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474 old_fd = unexec_open (old_name, O_RDONLY, 0);
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475 new_fd = unexec_open (new_name, O_RDWR | O_CREAT | O_TRUNC, 0666);
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476
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477 /* setup the header and the statbuf for old_fd */
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478 unexec_read (old_fd, 0, (char *) &old_hdr, sizeof (old_hdr));
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479 unexec_fstat (old_fd, &old_buf);
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480
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481
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482 /* set up some important constants */
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483 n_pagsiz = N_PAGSIZ (old_hdr);
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484 if (dynamic_addr)
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485 plt_end = (caddr_t) MASK_UP (ld2->ld_plt + ld2->ld_plt_sz, sizeof (double));
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486 else
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487 plt_end = (caddr_t) N_DATADDR (old_hdr);
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488
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489 /* never write protect the variable "environ", defined in /lib/crt0.o, and
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490 set in process.c and callproc.c */
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491 mprotect_bottom_addr = ((unsigned long) &environ) + sizeof (char **);
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492 /* never protect ABOVE the end of data emacs_edata specified */
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493 mprotect_top_addr = MIN (emacs_edata, N_DATADDR (old_hdr) + old_hdr.a_data);
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494
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495 /* Set up the image of the old file */
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496 old_base_addr = unexec_mmap (old_fd, old_buf.st_size, PROT_READ, MAP_PRIVATE);
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497 close (old_fd);
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498
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499 /* set up the new exec */
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500 new_hdr = old_hdr;
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501 new_hdr.a_data = (((unsigned long) MASK_UP (current_break, n_pagsiz)) -
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502 ((unsigned long) N_DATADDR (old_hdr)));
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503 new_hdr.a_bss = 0;
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504
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505 /* set up this variable, in case we want to reset "the break"
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506 when restarting */
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507 sbrk_of_0_at_unexec = ((unsigned long) MASK_UP (current_break, n_pagsiz));
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508
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509 /* Write out the first approximation to the new file. The sizes of
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510 each section will be correct, but there will be a number of
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511 corrections that will need to be made. */
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512 {
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513 long old_datoff = N_DATOFF (old_hdr);
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514 long old_dataddr = N_DATADDR (old_hdr);
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515 long new_treloff = N_TRELOFF (new_hdr);
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516 long old_treloff = N_TRELOFF (old_hdr);
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517 long ld_so_size = ((unsigned long) plt_end) - old_dataddr;
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518 long real_data_size = current_break - plt_end;
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519 long pad_size =
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520 MASK_UP (current_break, n_pagsiz) - ((unsigned long) current_break);
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521
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522
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523 /* First, write the text segment with new header -- copy everything until
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524 the start of the data segment from the old file, and then go back and
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525 write the new header. */
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526 unexec_write (new_fd, 0, old_base_addr, old_datoff + ld_so_size);
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527 unexec_write (new_fd, 0, (char *) &new_hdr, sizeof (new_hdr));
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528
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529 /* Copy the rest of the data segment from the running image. */
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530 unexec_write (new_fd, old_datoff + ld_so_size,
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531 plt_end, real_data_size);
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532
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533 /* pad out the data segment */
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534 unexec_pad (new_fd, pad_size);
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535
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536 /* Finally, copy the symbol table information from the old file. */
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537 unexec_write (new_fd, new_treloff,
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538 old_base_addr + old_treloff,
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539 old_buf.st_size - old_treloff);
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540 }
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541
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542
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543 /* Next, map in the output file so that we can jump around fixing it
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544 up. We retain the old file so that we can refer to it. */
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545 unexec_fstat (new_fd, &new_buf);
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546 new_base_addr = unexec_mmap (new_fd,
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547 MASK_UP (new_buf.st_size, page_size),
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548 PROT_READ | PROT_WRITE, MAP_SHARED);
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549
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550
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551
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552 /* We need to do 2 things. First, make sure that _edata and _end (and
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553 hence, curbrk) are set to the correct values. At the same time, for
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554 neatness and to help with debugging, mark all the types of all ld.so
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555 and nm BSS symbols in the new file to be DATA, and make sure that
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556 there are no COMMON symbols in the output file, as any references to
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557 these can lose really big. Second, reset all of the ld.so "relocation
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558 sites" in the new file to have the values that appear in the old file
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559 -- the failure to do this was the biggest loser in the old version of
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560 this code. */
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561
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562 /* STEP 1 */
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563 {
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564 /* Reset the regular symbol table first. */
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565 reset_symtab ((struct nlist *) (new_base_addr + N_SYMOFF(new_hdr)),
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566 (struct nlist *) (new_base_addr + N_SYMOFF(new_hdr) +
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567 new_hdr.a_syms),
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568 (char *) (new_base_addr + N_STROFF(new_hdr)),
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569 N_DATADDR (new_hdr) + new_hdr.a_data,
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570 N_BSSADDR (new_hdr) + new_hdr.a_bss,
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571 0, !!dynamic_addr);
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572 /* Now reset the ld.so symbol table. */
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573 if (dynamic_addr)
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574 reset_symtab ((struct nlist *) (new_base_addr + ld2->ld_stab),
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575 (struct nlist *) (new_base_addr + ld2->ld_symbols),
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576 (char *) (new_base_addr + ld2->ld_symbols),
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577 N_DATADDR (new_hdr) + new_hdr.a_data,
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578 N_BSSADDR (new_hdr) + new_hdr.a_bss,
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579 1, !!dynamic_addr);
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580 }
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581
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582 /* STEP 2 */
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583 if (dynamic_addr)
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584 {
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585 struct translation_struct ts;
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586 struct relocation_info *tmp =
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587 (struct relocation_info *) (old_base_addr + ld2->ld_rel);
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588 struct relocation_info *end =
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589 (struct relocation_info *)(old_base_addr + ld2->ld_hash);
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590
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591 /* set up the structure that we use to translate addresses in the
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592 old file into file offsets */
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593 ts.txtaddr = N_TXTADDR (old_hdr);
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594 ts.txtoff = N_TXTOFF (old_hdr);
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595 ts.dataddr = N_DATADDR (old_hdr);
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596 ts.datoff = N_DATOFF (old_hdr);
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597 ts.bssaddr = N_BSSADDR (old_hdr);
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598
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599 while (tmp < end)
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600 {
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601 copy_relocation_site (tmp, old_base_addr, new_base_addr, &ts);
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602 tmp++;
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603 }
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604 }
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605
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606
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607 /* get rid of the mmap-ed file space and make the output file
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608 executable -- then quit */
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609 munmap (new_base_addr, MASK_UP (new_buf.st_size, page_size));
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610 munmap (old_base_addr, MASK_UP (old_buf.st_size, page_size));
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611 unexec_fchmod (new_fd, 0755);
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612 close (new_fd);
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613 return 0;
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614 }
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615
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616
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617 int
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618 run_time_remap (char *dummy)
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619 {
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620 long page_size = getpagesize();
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621 unsigned long base_addr = MASK_UP (mprotect_bottom_addr, page_size);
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622 unsigned long top_addr = MASK_DOWN (mprotect_top_addr, page_size);
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623 long len = top_addr - base_addr;
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624
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625 if (!dynamic_addr)
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626 {
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627 unsigned long current_sbrk = (unsigned long) sbrk (0);
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628
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629 if (sbrk_of_0_at_unexec < current_sbrk)
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630 {
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631 if (sbrk_of_0_at_unexec != 0)
|
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632 /* GCC -Wall even catches incorrect printf type errors.
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633 How utterly cool. */
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|
634 fprintf (stderr,
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635 "Absurd new brk addr = 0x%lx (current = 0x%lx)\n",
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636 sbrk_of_0_at_unexec, current_sbrk);
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637 }
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638 else
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639 {
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640 errno = 0;
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641 if (brk ((caddr_t) sbrk_of_0_at_unexec))
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642 fprintf (stderr, "failed to change brk addr to 0x%lx: %s\n",
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643 sbrk_of_0_at_unexec, SYS_ERR);
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644 }
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645 }
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646
|
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647 if (len > 0)
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648 {
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649 errno = 0;
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|
650 if (mprotect ((caddr_t) base_addr, len, PROT_READ | PROT_EXEC))
|
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|
651 fprintf (stderr, "failed to change protection on data pages: %s\n",
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652 SYS_ERR);
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653 }
|
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654
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655 return 0;
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656 }
|
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657
|
