1 | /* Load a shared object at runtime, relocate it, and run its initializer. |
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2 | Copyright (C) 1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc. |
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3 | This file is part of the GNU C Library. |
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4 | |
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5 | The GNU C Library is free software; you can redistribute it and/or |
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6 | modify it under the terms of the GNU Lesser General Public |
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7 | License as published by the Free Software Foundation; either |
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8 | version 2.1 of the License, or (at your option) any later version. |
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9 | |
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10 | The GNU C Library is distributed in the hope that it will be useful, |
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11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 | Lesser General Public License for more details. |
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14 | |
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15 | You should have received a copy of the GNU Lesser General Public |
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16 | License along with the GNU C Library; if not, write to the Free |
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17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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18 | 02111-1307 USA. */ |
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19 | |
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20 | #include <assert.h> |
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21 | #include <dlfcn.h> |
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22 | #include <errno.h> |
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23 | #include <libintl.h> |
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24 | #include <stdlib.h> |
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25 | #include <string.h> |
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26 | #include <unistd.h> |
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27 | #include <sys/mman.h> /* Check whether MAP_COPY is defined. */ |
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28 | #include <sys/param.h> |
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29 | #include <ldsodefs.h> |
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30 | #include <bp-sym.h> |
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31 | |
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32 | #include <dl-dst.h> |
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33 | #include <machine/weakalias.h> |
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34 | |
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35 | |
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36 | extern ElfW(Addr) _dl_sysdep_start (void **start_argptr, |
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37 | void (*dl_main) (const ElfW(Phdr) *phdr, |
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38 | ElfW(Word) phnum, |
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39 | ElfW(Addr) *user_entry)) |
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40 | weak_function; |
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41 | |
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42 | /* This function is used to unload the cache file if necessary. */ |
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43 | extern void _dl_unload_cache (void); |
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44 | |
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45 | int __libc_argc = 0; |
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46 | char **__libc_argv = NULL; |
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47 | |
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48 | extern char **environ; |
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49 | |
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50 | extern int _dl_lazy; /* Do we do lazy relocations? */ |
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51 | |
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52 | /* Undefine the following for debugging. */ |
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53 | /* #define SCOPE_DEBUG 1 */ |
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54 | #ifdef SCOPE_DEBUG |
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55 | static void show_scope (struct link_map *new); |
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56 | #endif |
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57 | |
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58 | extern size_t _dl_platformlen; |
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59 | |
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60 | /* We must be carefull not to leave us in an inconsistent state. Thus we |
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61 | catch any error and re-raise it after cleaning up. */ |
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62 | |
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63 | struct dl_open_args |
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64 | { |
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65 | const char *file; |
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66 | int mode; |
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67 | const void *caller; |
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68 | struct link_map *map; |
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69 | }; |
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70 | |
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71 | |
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72 | static int |
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73 | add_to_global (struct link_map *new) |
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74 | { |
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75 | struct link_map **new_global; |
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76 | unsigned int to_add = 0; |
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77 | unsigned int cnt; |
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78 | |
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79 | /* Count the objects we have to put in the global scope. */ |
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80 | for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt) |
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81 | if (new->l_searchlist.r_list[cnt]->l_global == 0) |
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82 | ++to_add; |
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83 | |
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84 | /* The symbols of the new objects and its dependencies are to be |
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85 | introduced into the global scope that will be used to resolve |
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86 | references from other dynamically-loaded objects. |
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87 | |
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88 | The global scope is the searchlist in the main link map. We |
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89 | extend this list if necessary. There is one problem though: |
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90 | since this structure was allocated very early (before the libc |
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91 | is loaded) the memory it uses is allocated by the malloc()-stub |
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92 | in the ld.so. When we come here these functions are not used |
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93 | anymore. Instead the malloc() implementation of the libc is |
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94 | used. But this means the block from the main map cannot be used |
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95 | in an realloc() call. Therefore we allocate a completely new |
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96 | array the first time we have to add something to the locale scope. */ |
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97 | |
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98 | if (_dl_global_scope_alloc == 0) |
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99 | { |
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100 | /* This is the first dynamic object given global scope. */ |
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101 | _dl_global_scope_alloc = _dl_main_searchlist->r_nlist + to_add + 8; |
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102 | new_global = (struct link_map **) |
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103 | malloc (_dl_global_scope_alloc * sizeof (struct link_map *)); |
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104 | if (new_global == NULL) |
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105 | { |
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106 | _dl_global_scope_alloc = 0; |
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107 | nomem: |
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108 | _dl_signal_error (ENOMEM, new->l_libname->name, NULL, |
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109 | N_("cannot extend global scope")); |
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110 | return 1; |
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111 | } |
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112 | |
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113 | /* Copy over the old entries. */ |
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114 | memcpy (new_global, _dl_main_searchlist->r_list, |
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115 | (_dl_main_searchlist->r_nlist * sizeof (struct link_map *))); |
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116 | |
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117 | _dl_main_searchlist->r_list = new_global; |
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118 | } |
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119 | else if (_dl_main_searchlist->r_nlist + to_add > _dl_global_scope_alloc) |
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120 | { |
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121 | /* We have to extend the existing array of link maps in the |
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122 | main map. */ |
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123 | new_global = (struct link_map **) |
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124 | realloc (_dl_main_searchlist->r_list, |
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125 | ((_dl_global_scope_alloc + to_add + 8) |
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126 | * sizeof (struct link_map *))); |
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127 | if (new_global == NULL) |
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128 | goto nomem; |
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129 | |
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130 | _dl_global_scope_alloc += to_add + 8; |
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131 | _dl_main_searchlist->r_list = new_global; |
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132 | } |
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133 | |
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134 | /* Now add the new entries. */ |
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135 | for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt) |
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136 | { |
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137 | struct link_map *map = new->l_searchlist.r_list[cnt]; |
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138 | |
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139 | if (map->l_global == 0) |
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140 | { |
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141 | map->l_global = 1; |
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142 | _dl_main_searchlist->r_list[_dl_main_searchlist->r_nlist] = map; |
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143 | ++_dl_main_searchlist->r_nlist; |
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144 | } |
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145 | } |
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146 | |
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147 | return 0; |
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148 | } |
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149 | |
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150 | |
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151 | static void |
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152 | dl_open_worker (void *a) |
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153 | { |
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154 | struct dl_open_args *args = a; |
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155 | const char *file = args->file; |
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156 | int mode = args->mode; |
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157 | struct link_map *new, *l; |
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158 | const char *dst; |
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159 | int lazy; |
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160 | unsigned int i; |
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161 | |
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162 | /* Maybe we have to expand a DST. */ |
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163 | dst = strchr (file, '$'); |
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164 | if (dst != NULL) |
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165 | { |
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166 | const void *caller = args->caller; |
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167 | size_t len = strlen (file); |
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168 | size_t required; |
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169 | struct link_map *call_map; |
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170 | char *new_file; |
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171 | |
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172 | /* We have to find out from which object the caller is calling. */ |
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173 | call_map = NULL; |
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174 | for (l = _dl_loaded; l; l = l->l_next) |
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175 | if (caller >= (const void *) l->l_map_start |
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176 | && caller < (const void *) l->l_map_end) |
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177 | { |
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178 | /* There must be exactly one DSO for the range of the virtual |
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179 | memory. Otherwise something is really broken. */ |
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180 | call_map = l; |
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181 | break; |
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182 | } |
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183 | |
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184 | if (call_map == NULL) |
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185 | /* In this case we assume this is the main application. */ |
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186 | call_map = _dl_loaded; |
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187 | |
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188 | /* Determine how much space we need. We have to allocate the |
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189 | memory locally. */ |
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190 | required = DL_DST_REQUIRED (call_map, file, len, _dl_dst_count (dst, 0)); |
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191 | |
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192 | /* Get space for the new file name. */ |
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193 | new_file = (char *) alloca (required + 1); |
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194 | |
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195 | /* Generate the new file name. */ |
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196 | DL_DST_SUBSTITUTE (call_map, file, new_file, 0); |
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197 | |
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198 | /* If the substitution failed don't try to load. */ |
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199 | if (*new_file == '\0') |
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200 | _dl_signal_error (0, "dlopen", NULL, |
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201 | N_("empty dynamic string token substitution")); |
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202 | |
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203 | /* Now we have a new file name. */ |
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204 | file = new_file; |
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205 | } |
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206 | |
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207 | /* Load the named object. */ |
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208 | args->map = new = _dl_map_object (NULL, file, 0, lt_loaded, 0, |
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209 | mode); |
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210 | |
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211 | /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is |
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212 | set and the object is not already loaded. */ |
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213 | if (new == NULL) |
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214 | { |
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215 | assert (mode & RTLD_NOLOAD); |
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216 | return; |
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217 | } |
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218 | |
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219 | /* It was already open. */ |
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220 | if (new->l_searchlist.r_list != NULL) |
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221 | { |
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222 | /* Let the user know about the opencount. */ |
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223 | if (__builtin_expect (_dl_debug_mask & DL_DEBUG_FILES, 0)) |
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224 | _dl_debug_printf ("opening file=%s; opencount == %u\n\n", |
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225 | new->l_name, new->l_opencount); |
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226 | |
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227 | /* If the user requested the object to be in the global namespace |
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228 | but it is not so far, add it now. */ |
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229 | if ((mode & RTLD_GLOBAL) && new->l_global == 0) |
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230 | (void) add_to_global (new); |
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231 | |
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232 | /* Increment just the reference counter of the object. */ |
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233 | ++new->l_opencount; |
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234 | |
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235 | return; |
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236 | } |
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237 | |
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238 | /* Load that object's dependencies. */ |
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239 | _dl_map_object_deps (new, NULL, 0, 0); |
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240 | |
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241 | /* So far, so good. Now check the versions. */ |
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242 | for (i = 0; i < new->l_searchlist.r_nlist; ++i) |
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243 | if (new->l_searchlist.r_list[i]->l_versions == NULL) |
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244 | (void) _dl_check_map_versions (new->l_searchlist.r_list[i], 0, 0); |
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245 | |
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246 | #ifdef SCOPE_DEBUG |
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247 | show_scope (new); |
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248 | #endif |
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249 | |
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250 | /* Only do lazy relocation if `LD_BIND_NOW' is not set. */ |
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251 | lazy = (mode & RTLD_BINDING_MASK) == RTLD_LAZY && _dl_lazy; |
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252 | |
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253 | /* Relocate the objects loaded. We do this in reverse order so that copy |
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254 | relocs of earlier objects overwrite the data written by later objects. */ |
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255 | |
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256 | l = new; |
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257 | while (l->l_next) |
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258 | l = l->l_next; |
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259 | while (1) |
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260 | { |
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261 | if (! l->l_relocated) |
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262 | { |
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263 | #if 0 |
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264 | #ifdef SHARED |
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265 | if (_dl_profile != NULL) |
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266 | { |
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267 | /* If this here is the shared object which we want to profile |
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268 | make sure the profile is started. We can find out whether |
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269 | this is necessary or not by observing the `_dl_profile_map' |
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270 | variable. If was NULL but is not NULL afterwars we must |
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271 | start the profiling. */ |
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272 | struct link_map *old_profile_map = _dl_profile_map; |
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273 | |
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274 | _dl_relocate_object (l, l->l_scope, 1, 1); |
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275 | |
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276 | if (old_profile_map == NULL && _dl_profile_map != NULL) |
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277 | /* We must prepare the profiling. */ |
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278 | _dl_start_profile (_dl_profile_map, _dl_profile_output); |
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279 | } |
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280 | else |
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281 | #endif |
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282 | #endif |
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283 | _dl_relocate_object (l, l->l_scope, lazy, 0); |
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284 | } |
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285 | |
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286 | if (l == new) |
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287 | break; |
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288 | l = l->l_prev; |
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289 | } |
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290 | |
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291 | /* Increment the open count for all dependencies. If the file is |
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292 | not loaded as a dependency here add the search list of the newly |
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293 | loaded object to the scope. */ |
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294 | for (i = 0; i < new->l_searchlist.r_nlist; ++i) |
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295 | if (++new->l_searchlist.r_list[i]->l_opencount > 1 |
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296 | && new->l_searchlist.r_list[i]->l_type == lt_loaded) |
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297 | { |
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298 | struct link_map *imap = new->l_searchlist.r_list[i]; |
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299 | struct r_scope_elem **runp = imap->l_scope; |
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300 | size_t cnt = 0; |
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301 | |
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302 | while (*runp != NULL) |
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303 | { |
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304 | /* This can happen if imap was just loaded, but during |
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305 | relocation had l_opencount bumped because of relocation |
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306 | dependency. Avoid duplicates in l_scope. */ |
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307 | if (__builtin_expect (*runp == &new->l_searchlist, 0)) |
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308 | break; |
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309 | |
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310 | ++cnt; |
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311 | ++runp; |
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312 | } |
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313 | |
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314 | if (*runp != NULL) |
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315 | /* Avoid duplicates. */ |
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316 | continue; |
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317 | |
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318 | if (__builtin_expect (cnt + 1 >= imap->l_scope_max, 0)) |
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319 | { |
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320 | /* The 'r_scope' array is too small. Allocate a new one |
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321 | dynamically. */ |
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322 | struct r_scope_elem **newp; |
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323 | size_t new_size = imap->l_scope_max * 2; |
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324 | |
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325 | if (imap->l_scope == imap->l_scope_mem) |
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326 | { |
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327 | newp = (struct r_scope_elem **) |
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328 | malloc (new_size * sizeof (struct r_scope_elem *)); |
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329 | if (newp == NULL) |
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330 | _dl_signal_error (ENOMEM, "dlopen", NULL, |
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331 | N_("cannot create scope list")); |
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332 | imap->l_scope = memcpy (newp, imap->l_scope, |
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333 | cnt * sizeof (imap->l_scope[0])); |
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334 | } |
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335 | else |
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336 | { |
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337 | newp = (struct r_scope_elem **) |
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338 | realloc (imap->l_scope, |
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339 | new_size * sizeof (struct r_scope_elem *)); |
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340 | if (newp == NULL) |
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341 | _dl_signal_error (ENOMEM, "dlopen", NULL, |
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342 | N_("cannot create scope list")); |
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343 | imap->l_scope = newp; |
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344 | } |
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345 | |
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346 | imap->l_scope_max = new_size; |
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347 | } |
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348 | |
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349 | imap->l_scope[cnt++] = &new->l_searchlist; |
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350 | imap->l_scope[cnt] = NULL; |
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351 | } |
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352 | |
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353 | /* Run the initializer functions of new objects. */ |
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354 | _dl_init (new, __libc_argc, __libc_argv, environ); |
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355 | |
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356 | /* Now we can make the new map available in the global scope. */ |
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357 | if (mode & RTLD_GLOBAL) |
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358 | /* Move the object in the global namespace. */ |
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359 | if (add_to_global (new) != 0) |
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360 | /* It failed. */ |
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361 | return; |
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362 | |
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363 | /* Mark the object as not deletable if the RTLD_NODELETE flags was |
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364 | passed. */ |
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365 | if (__builtin_expect (mode & RTLD_NODELETE, 0)) |
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366 | new->l_flags_1 |= DF_1_NODELETE; |
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367 | |
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368 | /* Let the user know about the opencount. */ |
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369 | if (__builtin_expect (_dl_debug_mask & DL_DEBUG_FILES, 0)) |
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370 | _dl_debug_printf ("opening file=%s; opencount == %u\n\n", |
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371 | new->l_name, new->l_opencount); |
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372 | } |
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373 | |
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374 | |
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375 | void * |
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376 | internal_function |
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377 | _dl_open (const char *file, int mode, const void *caller) |
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378 | { |
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379 | struct dl_open_args args; |
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380 | const char *objname; |
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381 | const char *errstring; |
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382 | int errcode; |
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383 | |
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384 | if ((mode & RTLD_BINDING_MASK) == 0) |
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385 | /* One of the flags must be set. */ |
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386 | _dl_signal_error (EINVAL, file, NULL, N_("invalid mode for dlopen()")); |
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387 | |
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388 | /* Make sure we are alone. */ |
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389 | #ifdef HAVE_DD_LOCK |
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390 | __lock_acquire_recursive(_dl_load_lock); |
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391 | #endif |
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392 | |
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393 | args.file = file; |
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394 | args.mode = mode; |
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395 | args.caller = caller; |
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396 | args.map = NULL; |
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397 | errcode = _dl_catch_error (&objname, &errstring, dl_open_worker, &args); |
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398 | |
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399 | #ifndef MAP_COPY |
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400 | /* We must munmap() the cache file. */ |
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401 | _dl_unload_cache (); |
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402 | #endif |
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403 | |
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404 | /* Release the lock. */ |
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405 | #ifdef HAVE_DD_LOCK |
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406 | __lock_release_recursive(_dl_load_lock); |
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407 | #endif |
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408 | |
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409 | |
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410 | if (errstring) |
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411 | { |
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412 | /* Some error occurred during loading. */ |
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413 | char *local_errstring; |
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414 | size_t len_errstring; |
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415 | |
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416 | /* Remove the object from memory. It may be in an inconsistent |
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417 | state if relocation failed, for example. */ |
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418 | if (args.map) |
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419 | { |
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420 | unsigned int i; |
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421 | |
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422 | /* Increment open counters for all objects since this has |
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423 | not happened yet. */ |
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424 | for (i = 0; i < args.map->l_searchlist.r_nlist; ++i) |
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425 | ++args.map->l_searchlist.r_list[i]->l_opencount; |
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426 | |
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427 | _dl_close (args.map); |
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428 | } |
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429 | |
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430 | /* Make a local copy of the error string so that we can release the |
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431 | memory allocated for it. */ |
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432 | len_errstring = strlen (errstring) + 1; |
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433 | if (objname == errstring + len_errstring) |
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434 | { |
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435 | size_t total_len = len_errstring + strlen (objname) + 1; |
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436 | local_errstring = alloca (total_len); |
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437 | memcpy (local_errstring, errstring, total_len); |
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438 | objname = local_errstring + len_errstring; |
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439 | } |
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440 | else |
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441 | { |
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442 | local_errstring = alloca (len_errstring); |
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443 | memcpy (local_errstring, errstring, len_errstring); |
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444 | } |
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445 | |
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446 | if (errstring != _dl_out_of_memory) |
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447 | free ((char *) errstring); |
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448 | |
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449 | /* Reraise the error. */ |
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450 | _dl_signal_error (errcode, objname, NULL, local_errstring); |
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451 | } |
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452 | |
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453 | #ifndef SHARED |
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454 | DL_STATIC_INIT (args.map); |
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455 | #endif |
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456 | |
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457 | return args.map; |
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458 | } |
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459 | |
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460 | |
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461 | #ifdef SCOPE_DEBUG |
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462 | #include <unistd.h> |
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463 | |
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464 | static void |
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465 | show_scope (struct link_map *new) |
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466 | { |
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467 | int scope_cnt; |
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468 | |
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469 | for (scope_cnt = 0; new->l_scope[scope_cnt] != NULL; ++scope_cnt) |
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470 | { |
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471 | char numbuf[2]; |
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472 | unsigned int cnt; |
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473 | |
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474 | numbuf[0] = '0' + scope_cnt; |
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475 | numbuf[1] = '\0'; |
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476 | _dl_printf ("scope %s:", numbuf); |
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477 | |
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478 | for (cnt = 0; cnt < new->l_scope[scope_cnt]->r_nlist; ++cnt) |
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479 | if (*new->l_scope[scope_cnt]->r_list[cnt]->l_name) |
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480 | _dl_printf (" %s", new->l_scope[scope_cnt]->r_list[cnt]->l_name); |
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481 | else |
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482 | _dl_printf (" <main>"); |
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483 | |
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484 | _dl_printf ("\n"); |
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485 | } |
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486 | } |
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487 | #endif |
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