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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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2286
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54 #include "compiler.h"
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0
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55
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56 /********************** Macros *************************************/
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57
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58 #define SYS_ERR \
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59 ((errno > 0)?((errno < sys_nerr)?(sys_errlist[errno]):\
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60 "unknown system error"): "unknown error")
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61
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62 #define MASK_UP(x,p_of_two) \
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63 ((((unsigned long) (x)) + ((p_of_two) - 1)) & (~((p_of_two) - 1)))
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64
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65 #define MASK_DOWN(x,p_of_two) (((unsigned long) (x)) & (~((p_of_two) - 1)))
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66
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67 #ifndef mc68020
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68 #define relocation_info reloc_info_sparc
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69 #endif
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70
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71 /********************** Typedefs and Structs ***********************/
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72
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73 struct translation_struct
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74 {
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75 long txtaddr;
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76 long txtoff;
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77 long dataddr;
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78 long datoff;
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79 long bssaddr;
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80 };
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81
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82 /********************** Function Prototypes/Declarations ***********/
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83
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398
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84 static void unexec_error (const char *m, int use_errno, ...);
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0
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85 static int unexec_open (char *filename, int flag, int mode);
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86 static caddr_t unexec_mmap (int fd, size_t len, int prot, int flags);
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87 static long unexec_seek (int fd, long position);
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88 static void unexec_read (int fd, long position, char *buf, int bytes);
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89 static void unexec_write (int fd, long position, char *buf, int bytes);
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90 static void unexec_pad (int fd, int bytes);
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91 static void unexec_fstat (int fd, struct stat *statptr);
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92 static void unexec_fchmod (int fd, int mode);
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93 static long unexec_addr_to_offset (long addr, struct translation_struct *ts);
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94 static void copy_relocation_site (struct relocation_info *ri,
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95 caddr_t from_base_addr,
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96 caddr_t to_base_addr,
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97 struct translation_struct *ts);
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98 static void reset_symtab (struct nlist *start, struct nlist *end,
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99 char *strtab, long edata_value, long end_value,
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100 int ld_so_table, int shlib_image);
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101 int run_time_remap (char *dummy);
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102
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103 /********************** Variables **********************************/
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104
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105 /* for reporting error messages from system calls */
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106 extern int sys_nerr;
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107 extern char *sys_errlist[];
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108 extern int errno;
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109 extern int _DYNAMIC;
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110 extern char **environ;
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111
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112 static unsigned long mprotect_bottom_addr;
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113 static unsigned long mprotect_top_addr;
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114
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115 static unsigned long sbrk_of_0_at_unexec;
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116
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117 /*******************************************************************/
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118
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119 static void
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398
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120 unexec_error (const char *fmt, int use_errno, ...)
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0
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121 {
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398
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122 const char *err_msg = SYS_ERR;
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0
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123 va_list args;
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124
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125 fprintf (stderr, "unexec - ");
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126 va_start (args, use_errno);
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127 vfprintf (stderr, fmt, args);
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128 va_end (args);
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129
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130 if (use_errno)
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131 fprintf (stderr, ": %s", err_msg);
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132 fprintf (stderr, "\n");
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133 exit (1);
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134 return;
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135 }
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136
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137 static int
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138 unexec_open (char *filename, int flag, int mode)
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139 {
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140 int fd;
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141
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142 errno = 0;
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143
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144 fd = open (filename, flag, mode);
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145
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146 if (fd < 0)
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147 unexec_error ("Failure opening file %s", 1, (void *) filename, 0, 0);
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148 return fd;
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149 }
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150
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151 static caddr_t
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152 unexec_mmap (int fd, size_t len, int prot, int flags)
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153 {
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154 caddr_t return_val;
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155
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156 unexec_seek (fd, 0);
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157 errno = 0;
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158 return_val = mmap (0, len, prot, flags, fd, 0);
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159
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160 if (return_val == (caddr_t) -1)
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161 unexec_error ("Failure mmap'ing file", 1, 0, 0, 0);
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162 return return_val;
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163 }
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164
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165
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166 static long
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167 unexec_seek (int fd, long position)
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168 {
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169 long seek_value;
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170
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171 if (fd <= 0)
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172 unexec_error ("No file open in which to seek", 0, 0, 0, 0);
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173
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174 errno = 0;
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175
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176 if (position < 0)
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177 seek_value = (long) lseek (fd, 0, L_INCR);
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178 else
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179 seek_value = (long) lseek (fd, position, L_SET);
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180
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181 if (seek_value < 0)
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182 unexec_error ("Failed to do a seek to 0x%x in %s", 1,
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183 (char *) position, "unexec() output file", 0);
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184
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185 return seek_value;
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186 }
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187
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188 static void
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189 unexec_read (int fd, long position, char *buf, int bytes)
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190 {
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191 int n_read;
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192 int remains = bytes;
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193 position = unexec_seek (fd, position);
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194
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195 if (bytes < 0)
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196 unexec_error ("Attempted read of %d bytes", 0, (char *) bytes, 0, 0);
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197
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198 errno = 0;
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199
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200 while (remains > 0)
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201 {
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202 n_read = read (fd, buf, remains);
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203 if (n_read <= 0)
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204 unexec_error ("Read failed for 0x%x bytes at offset 0x%x in %s",
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205 1, (char *) bytes, (char *) position,
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206 "unexec() output file");
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207 buf += n_read;
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208 remains -= n_read;
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209 }
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210
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211 return;
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212 }
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213
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214 static void
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215 unexec_write (int fd, long position, char *buf, int bytes)
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216 {
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217 int n_written;
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218 int remains = bytes;
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219 position = unexec_seek (fd, position);
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220
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221 if (bytes < 0)
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222 unexec_error ("Attempted write of %d bytes in %s",
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223 0, (char *) bytes, "unexec() output file", 0);
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224
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225 errno = 0;
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226
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227 while (remains > 0)
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228 {
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229 n_written = write (fd, buf, remains);
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230 if (n_written <= 0)
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231 unexec_error ("Write failed for 0x%x bytes at offset 0x%x in %s",
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232 1, (char *) bytes, (char *) position,
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233 "unexec() output file");
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234 buf += n_written;
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235 remains -= n_written;
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236 }
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237
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238 return;
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239 }
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240
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241 static void
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242 unexec_pad (int fd, int bytes)
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243 {
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244 if (bytes > 0)
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245 {
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246 char buf[1024];
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247 int remaining = bytes;
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248
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249 memset (buf, 0, sizeof (buf));
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250
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251 while (remaining > 0)
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252 {
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253 int this_write = (remaining > sizeof(buf))?sizeof(buf):remaining;
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254 unexec_write (fd, -1, buf, this_write);
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255 remaining -= this_write;
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256 }
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257 }
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258 }
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259
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260 static void
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261 unexec_fstat (int fd, struct stat *statptr)
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262 {
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263 errno = 0;
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264 if (-1 == fstat (fd, statptr))
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265 unexec_error ("fstat() failed for descriptor %d", 1, (char *) fd, 0, 0);
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266 return;
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267 }
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268
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269 static void
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270 unexec_fchmod (int fd, int mode)
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271 {
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272 errno = 0;
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273 if (-1 == fchmod (fd, mode))
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274 unexec_error ("fchmod() failed for descriptor %d", 1, (char *) fd, 0, 0);
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275 return;
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276 }
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277
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278 static long
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279 unexec_addr_to_offset (long addr, struct translation_struct *ts)
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280
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281 {
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282 if ((addr < ts->txtaddr) || (addr >= ts->bssaddr))
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283 unexec_error ("bad address 0x%x to addr_to_offset()",
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284 0, (char *) addr, 0, 0);
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285 if (addr >= ts->dataddr)
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286 return ((long) ((addr - ts->dataddr) + ts->datoff));
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287 else
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288 return ((long) ((addr - ts->txtaddr) + ts->txtoff));
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289 }
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290
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291
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292 /*
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293 * "LD.SO" DATA AND SYMBOL TABLE OPERATIONS
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294 */
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295
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296 static void
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297 copy_relocation_site (struct relocation_info *ri,
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298 caddr_t from_base_addr,
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299 caddr_t to_base_addr,
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300 struct translation_struct *ts)
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301 {
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302 long offset = unexec_addr_to_offset (ri->r_address, ts);
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303 caddr_t from = from_base_addr + offset;
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304 caddr_t to = to_base_addr + offset;
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305
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306 #ifdef mc68020
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307 #define r_type r_length
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308 #endif /* mc68020 */
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309 switch (ri->r_type)
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310 {
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311 #ifdef mc68020
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312 case 0:
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313 *((char *) to) = *((char *) from);
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314 break;
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315 case 1:
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316 *((short *) to) = *((short *) from);
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317 break;
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318 case 2:
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319 *((long *) to) = *((long *) from);
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320 break;
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321 #else /* !mc68020 */
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322 case RELOC_8:
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323 case RELOC_DISP8:
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324 *((char *) to) = *((char *) from);
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325 break;
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326 case RELOC_16:
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327 case RELOC_DISP16:
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328 *((short *) to) = *((short *) from);
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329 break;
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330 case RELOC_LO10:
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331 case RELOC_13:
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332 case RELOC_22:
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333 case RELOC_HI22:
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334 case RELOC_WDISP22:
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335 case RELOC_WDISP30:
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336 case RELOC_32:
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337 case RELOC_DISP32:
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338 case RELOC_GLOB_DAT:
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339 *((long *) to) = *((long *) from);
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340 break;
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341 case RELOC_JMP_SLOT:
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342 {
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343 long *target = (long *) to;
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344 long *source = (long *) from;
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345 *target = *source;
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346 target++;
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347 source++;
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348 *target = *source;
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349 target++;
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350 source++;
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351 *target = *source;
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352 }
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353 break;
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354 #endif /* !mc68020 */
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355 default:
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356 unexec_error ("unknown reloc type %d seen during unexec()",
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357 0, (char *) ri->r_type, 0, 0);
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358 break;
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359 }
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360 return;
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361 }
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362
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363 static void
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364 reset_symtab (struct nlist *start, struct nlist *end, char *strtab,
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365 long edata_value, long end_value, int ld_so_table,
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366 int shlib_image)
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367 {
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368 struct nlist *tmp = start;
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369 int found_edata = 0;
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370 int found_end = 0;
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371
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372 while (tmp < end)
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373 {
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374 int type = tmp->n_type;
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375 int named = (ld_so_table)?1:(tmp->n_un.n_strx);
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376
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377 if ((type == (N_UNDF | N_EXT)) &&
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378 (tmp->n_value != 0))
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379 unexec_error ("unexec'ing image has COMMON symbols in it -- we quit!",
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380 0, 0, 0, 0);
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381
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382 if (!(type & N_STAB))
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383 {
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384 if (!found_edata &&
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385 (type == (N_EXT | N_DATA)) &&
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386 named &&
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387 !strcmp ("_edata", strtab + tmp->n_un.n_strx))
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388 {
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389 tmp->n_value = edata_value;
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390 found_edata = 1;
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391 }
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392
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393
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394 if ((type & N_TYPE) == N_BSS)
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395 {
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396 if (!found_end &&
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397 (type == (N_EXT | N_BSS)) &&
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398 named &&
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399 !strcmp ("_end", strtab + tmp->n_un.n_strx))
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400 {
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401 tmp->n_value = end_value;
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402 found_end = 1;
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403 }
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404 else if (type & N_EXT)
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405 tmp->n_type = N_DATA | N_EXT;
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406 else
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407 tmp->n_type = N_DATA;
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408 }
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409
|
|
|
410 /* the way things are being handled here, having sbrk() in the
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|
411 image is fatal for an image linked with shared lib's (although
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|
|
412 the code could be modified to support it), but this should
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|
|
413 never happen anyway */
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|
|
414 if (shlib_image &&
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415 (type == (N_EXT | N_TEXT)) &&
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416 named &&
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417 !strcmp ("_sbrk", strtab + tmp->n_un.n_strx))
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|
418 unexec_error ("unexec'd shlib image has sbrk() in it -- we quit!",
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|
|
419 0, 0, 0, 0);
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420 }
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421
|
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422 tmp++;
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423 }
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424 }
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425
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426 extern int getpagesize (void);
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427
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428 /*
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429 * EXPORTED FUNCTIONS
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430 */
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431
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432 /* this has to be a global variable to prevent the optimizers from
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433 * assuming that it can not be 0.
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434 */
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435 static void *dynamic_addr = (void *) &_DYNAMIC;
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436
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437 int
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2286
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438 unexec (char *new_name, char *old_name, unsigned int emacs_edata,
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439 unsigned int UNUSED (dummy1), unsigned int UNUSED (dummy2))
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0
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440 {
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441 /* ld.so data */
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442 struct link_dynamic *ld = 0;
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443 struct link_dynamic_2 *ld2 = 0;
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444 /* old and new state */
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445 int old_fd;
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446 int new_fd;
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447 caddr_t old_base_addr;
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448 caddr_t new_base_addr;
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449 struct exec old_hdr;
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450 struct exec new_hdr;
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451 struct stat old_buf;
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452 struct stat new_buf;
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453 /* some process specific "constants" */
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454 unsigned long n_pagsiz;
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455 long page_size = getpagesize ();
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456 caddr_t plt_end;
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457 caddr_t current_break = (caddr_t) sbrk (0);
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458
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459 if (!page_size)
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460 unexec_error ("unexec() failed because we can't get the size of a page!",
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461 0, 0, 0, 0);
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462
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463 /* see if this is a -Bdynamic image -- if so, find ld.so structures */
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464 if (dynamic_addr)
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465 {
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466 ld = (struct link_dynamic *) dynamic_addr;
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467 ld2 = ld->ld_un.ld_2;
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468 if (ld->ld_version < 2)
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469 unexec_error ("%s linked with obsolete version of ld -- we quit!",
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470 0, old_name, 0, 0);
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471 }
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472
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473 /* open the old and new files, figuring out how big the old one is
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474 so that we can map it in */
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475 old_fd = unexec_open (old_name, O_RDONLY, 0);
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476 new_fd = unexec_open (new_name, O_RDWR | O_CREAT | O_TRUNC, 0666);
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477
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478 /* setup the header and the statbuf for old_fd */
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479 unexec_read (old_fd, 0, (char *) &old_hdr, sizeof (old_hdr));
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480 unexec_fstat (old_fd, &old_buf);
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481
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482
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483 /* set up some important constants */
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484 n_pagsiz = N_PAGSIZ (old_hdr);
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485 if (dynamic_addr)
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486 plt_end = (caddr_t) MASK_UP (ld2->ld_plt + ld2->ld_plt_sz, sizeof (double));
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487 else
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488 plt_end = (caddr_t) N_DATADDR (old_hdr);
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489
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490 /* never write protect the variable "environ", defined in /lib/crt0.o, and
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853
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491 set in process.c */
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0
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492 mprotect_bottom_addr = ((unsigned long) &environ) + sizeof (char **);
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493 /* never protect ABOVE the end of data emacs_edata specified */
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494 mprotect_top_addr = MIN (emacs_edata, N_DATADDR (old_hdr) + old_hdr.a_data);
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495
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496 /* Set up the image of the old file */
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497 old_base_addr = unexec_mmap (old_fd, old_buf.st_size, PROT_READ, MAP_PRIVATE);
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498 close (old_fd);
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499
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500 /* set up the new exec */
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501 new_hdr = old_hdr;
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502 new_hdr.a_data = (((unsigned long) MASK_UP (current_break, n_pagsiz)) -
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503 ((unsigned long) N_DATADDR (old_hdr)));
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504 new_hdr.a_bss = 0;
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505
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506 /* set up this variable, in case we want to reset "the break"
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507 when restarting */
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508 sbrk_of_0_at_unexec = ((unsigned long) MASK_UP (current_break, n_pagsiz));
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509
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510 /* Write out the first approximation to the new file. The sizes of
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511 each section will be correct, but there will be a number of
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512 corrections that will need to be made. */
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513 {
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514 long old_datoff = N_DATOFF (old_hdr);
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515 long old_dataddr = N_DATADDR (old_hdr);
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516 long new_treloff = N_TRELOFF (new_hdr);
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517 long old_treloff = N_TRELOFF (old_hdr);
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518 long ld_so_size = ((unsigned long) plt_end) - old_dataddr;
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519 long real_data_size = current_break - plt_end;
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520 long pad_size =
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521 MASK_UP (current_break, n_pagsiz) - ((unsigned long) current_break);
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522
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523
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524 /* First, write the text segment with new header -- copy everything until
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525 the start of the data segment from the old file, and then go back and
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526 write the new header. */
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527 unexec_write (new_fd, 0, old_base_addr, old_datoff + ld_so_size);
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528 unexec_write (new_fd, 0, (char *) &new_hdr, sizeof (new_hdr));
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529
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530 /* Copy the rest of the data segment from the running image. */
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531 unexec_write (new_fd, old_datoff + ld_so_size,
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532 plt_end, real_data_size);
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533
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534 /* pad out the data segment */
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535 unexec_pad (new_fd, pad_size);
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536
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537 /* Finally, copy the symbol table information from the old file. */
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538 unexec_write (new_fd, new_treloff,
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539 old_base_addr + old_treloff,
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540 old_buf.st_size - old_treloff);
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541 }
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542
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543
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544 /* Next, map in the output file so that we can jump around fixing it
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545 up. We retain the old file so that we can refer to it. */
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546 unexec_fstat (new_fd, &new_buf);
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547 new_base_addr = unexec_mmap (new_fd,
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548 MASK_UP (new_buf.st_size, page_size),
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549 PROT_READ | PROT_WRITE, MAP_SHARED);
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550
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551
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552
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553 /* We need to do 2 things. First, make sure that _edata and _end (and
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554 hence, curbrk) are set to the correct values. At the same time, for
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555 neatness and to help with debugging, mark all the types of all ld.so
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556 and nm BSS symbols in the new file to be DATA, and make sure that
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557 there are no COMMON symbols in the output file, as any references to
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558 these can lose really big. Second, reset all of the ld.so "relocation
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559 sites" in the new file to have the values that appear in the old file
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560 -- the failure to do this was the biggest loser in the old version of
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561 this code. */
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562
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563 /* STEP 1 */
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564 {
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565 /* Reset the regular symbol table first. */
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566 reset_symtab ((struct nlist *) (new_base_addr + N_SYMOFF(new_hdr)),
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567 (struct nlist *) (new_base_addr + N_SYMOFF(new_hdr) +
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568 new_hdr.a_syms),
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569 (char *) (new_base_addr + N_STROFF(new_hdr)),
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570 N_DATADDR (new_hdr) + new_hdr.a_data,
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571 N_BSSADDR (new_hdr) + new_hdr.a_bss,
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572 0, !!dynamic_addr);
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573 /* Now reset the ld.so symbol table. */
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574 if (dynamic_addr)
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575 reset_symtab ((struct nlist *) (new_base_addr + ld2->ld_stab),
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576 (struct nlist *) (new_base_addr + ld2->ld_symbols),
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577 (char *) (new_base_addr + ld2->ld_symbols),
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578 N_DATADDR (new_hdr) + new_hdr.a_data,
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579 N_BSSADDR (new_hdr) + new_hdr.a_bss,
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580 1, !!dynamic_addr);
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581 }
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582
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583 /* STEP 2 */
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584 if (dynamic_addr)
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585 {
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586 struct translation_struct ts;
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587 struct relocation_info *tmp =
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588 (struct relocation_info *) (old_base_addr + ld2->ld_rel);
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589 struct relocation_info *end =
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590 (struct relocation_info *)(old_base_addr + ld2->ld_hash);
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591
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592 /* set up the structure that we use to translate addresses in the
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593 old file into file offsets */
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594 ts.txtaddr = N_TXTADDR (old_hdr);
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595 ts.txtoff = N_TXTOFF (old_hdr);
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596 ts.dataddr = N_DATADDR (old_hdr);
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597 ts.datoff = N_DATOFF (old_hdr);
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598 ts.bssaddr = N_BSSADDR (old_hdr);
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599
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600 while (tmp < end)
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601 {
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602 copy_relocation_site (tmp, old_base_addr, new_base_addr, &ts);
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603 tmp++;
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604 }
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605 }
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606
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607
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608 /* get rid of the mmap-ed file space and make the output file
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609 executable -- then quit */
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610 munmap (new_base_addr, MASK_UP (new_buf.st_size, page_size));
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611 munmap (old_base_addr, MASK_UP (old_buf.st_size, page_size));
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612 unexec_fchmod (new_fd, 0755);
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613 close (new_fd);
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614 return 0;
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615 }
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616
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617
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618 int
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2286
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619 run_time_remap (char *UNUSED (dummy))
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0
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620 {
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621 long page_size = getpagesize();
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622 unsigned long base_addr = MASK_UP (mprotect_bottom_addr, page_size);
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623 unsigned long top_addr = MASK_DOWN (mprotect_top_addr, page_size);
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624 long len = top_addr - base_addr;
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625
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626 if (!dynamic_addr)
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627 {
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628 unsigned long current_sbrk = (unsigned long) sbrk (0);
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629
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630 if (sbrk_of_0_at_unexec < current_sbrk)
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631 {
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632 if (sbrk_of_0_at_unexec != 0)
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633 /* GCC -Wall even catches incorrect printf type errors.
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634 How utterly cool. */
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635 fprintf (stderr,
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636 "Absurd new brk addr = 0x%lx (current = 0x%lx)\n",
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637 sbrk_of_0_at_unexec, current_sbrk);
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638 }
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639 else
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640 {
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641 errno = 0;
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642 if (brk ((caddr_t) sbrk_of_0_at_unexec))
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643 fprintf (stderr, "failed to change brk addr to 0x%lx: %s\n",
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644 sbrk_of_0_at_unexec, SYS_ERR);
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645 }
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646 }
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647
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648 if (len > 0)
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649 {
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650 errno = 0;
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651 if (mprotect ((caddr_t) base_addr, len, PROT_READ | PROT_EXEC))
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652 fprintf (stderr, "failed to change protection on data pages: %s\n",
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653 SYS_ERR);
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654 }
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655
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656 return 0;
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657 }
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658
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