1 | /* Handle symbol and library versioning. |
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2 | Copyright (C) 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 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. |
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5 | |
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6 | The GNU C Library is free software; you can redistribute it and/or |
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7 | modify it under the terms of the GNU Lesser General Public |
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8 | License as published by the Free Software Foundation; either |
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9 | version 2.1 of the License, or (at your option) any later version. |
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10 | |
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11 | The GNU C Library is distributed in the hope that it will be useful, |
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12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 | Lesser General Public License for more details. |
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15 | |
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16 | You should have received a copy of the GNU Lesser General Public |
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17 | License along with the GNU C Library; if not, write to the Free |
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18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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19 | 02111-1307 USA. */ |
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20 | |
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21 | #include <elf.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 <ldsodefs.h> |
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27 | |
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28 | #include <assert.h> |
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29 | |
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30 | |
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31 | #ifndef VERSYMIDX |
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32 | # define VERSYMIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (tag)) |
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33 | #endif |
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34 | |
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35 | |
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36 | #define make_string(string, rest...) \ |
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37 | ({ \ |
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38 | const char *all[] = { string, ## rest }; \ |
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39 | size_t len, cnt; \ |
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40 | char *result, *cp; \ |
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41 | \ |
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42 | len = 1; \ |
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43 | for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt) \ |
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44 | len += strlen (all[cnt]); \ |
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45 | \ |
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46 | cp = result = alloca (len); \ |
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47 | for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt) \ |
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48 | { \ |
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49 | cp = strcpy (cp, all[cnt]); \ |
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50 | cp += strlen (all[cnt]); \ |
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51 | } \ |
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52 | \ |
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53 | result; \ |
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54 | }) |
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55 | |
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56 | |
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57 | static inline struct link_map * |
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58 | find_needed (const char *name, struct link_map *map) |
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59 | { |
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60 | struct link_map *tmap; |
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61 | unsigned int n; |
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62 | |
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63 | for (tmap = _dl_loaded; tmap != NULL; tmap = tmap->l_next) |
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64 | if (_dl_name_match_p (name, tmap)) |
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65 | return tmap; |
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66 | |
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67 | /* The required object is not in the global scope, look to see if it is |
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68 | a dependency of the current object. */ |
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69 | for (n = 0; n < map->l_searchlist.r_nlist; n++) |
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70 | if (_dl_name_match_p (name, map->l_searchlist.r_list[n])) |
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71 | return map->l_searchlist.r_list[n]; |
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72 | |
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73 | /* Should never happen. */ |
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74 | return NULL; |
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75 | } |
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76 | |
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77 | |
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78 | static int |
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79 | internal_function |
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80 | match_symbol (const char *name, ElfW(Word) hash, const char *string, |
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81 | struct link_map *map, int verbose, int weak) |
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82 | { |
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83 | const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); |
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84 | ElfW(Addr) def_offset; |
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85 | ElfW(Verdef) *def; |
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86 | /* Initialize to make the compiler happy. */ |
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87 | const char *errstring = NULL; |
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88 | int result = 0; |
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89 | |
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90 | /* Display information about what we are doing while debugging. */ |
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91 | if (__builtin_expect (_dl_debug_mask & DL_DEBUG_VERSIONS, 0)) |
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92 | _dl_debug_printf ("\ |
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93 | checking for version `%s' in file %s required by file %s\n", |
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94 | string, map->l_name[0] ? map->l_name : _dl_argv[0], |
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95 | name); |
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96 | |
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97 | if (__builtin_expect (map->l_info[VERSYMIDX (DT_VERDEF)] == NULL, 0)) |
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98 | { |
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99 | /* The file has no symbol versioning. I.e., the dependent |
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100 | object was linked against another version of this file. We |
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101 | only print a message if verbose output is requested. */ |
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102 | if (verbose) |
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103 | { |
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104 | /* XXX We cannot translate the messages. */ |
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105 | errstring = make_string ("\ |
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106 | no version information available (required by ", name, ")"); |
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107 | goto call_cerror; |
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108 | } |
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109 | return 0; |
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110 | } |
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111 | |
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112 | def_offset = map->l_info[VERSYMIDX (DT_VERDEF)]->d_un.d_ptr; |
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113 | assert (def_offset != 0); |
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114 | |
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115 | def = (ElfW(Verdef) *) ((char *) map->l_addr + def_offset); |
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116 | while (1) |
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117 | { |
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118 | /* Currently the version number of the definition entry is 1. |
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119 | Make sure all we see is this version. */ |
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120 | if (__builtin_expect (def->vd_version, 1) != 1) |
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121 | { |
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122 | char buf[20]; |
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123 | buf[sizeof (buf) - 1] = '\0'; |
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124 | /* XXX We cannot translate the message. */ |
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125 | errstring = make_string ("unsupported version of Verdef record"); |
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126 | result = 1; |
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127 | goto call_cerror; |
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128 | } |
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129 | |
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130 | /* Compare the hash values. */ |
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131 | if (hash == def->vd_hash) |
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132 | { |
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133 | ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux); |
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134 | |
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135 | /* To be safe, compare the string as well. */ |
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136 | if (__builtin_expect (strcmp (string, strtab + aux->vda_name), 0) |
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137 | == 0) |
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138 | /* Bingo! */ |
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139 | return 0; |
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140 | } |
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141 | |
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142 | /* If no more definitions we failed to find what we want. */ |
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143 | if (def->vd_next == 0) |
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144 | break; |
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145 | |
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146 | /* Next definition. */ |
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147 | def = (ElfW(Verdef) *) ((char *) def + def->vd_next); |
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148 | } |
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149 | |
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150 | /* Symbol not found. If it was a weak reference it is not fatal. */ |
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151 | if (__builtin_expect (weak, 1)) |
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152 | { |
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153 | if (verbose) |
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154 | { |
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155 | /* XXX We cannot translate the message. */ |
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156 | errstring = make_string ("weak version `", string, |
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157 | "' not found (required by ", name, ")"); |
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158 | goto call_cerror; |
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159 | } |
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160 | return 0; |
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161 | } |
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162 | |
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163 | /* XXX We cannot translate the message. */ |
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164 | errstring = make_string ("version `", string, "' not found (required by ", |
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165 | name, ")"); |
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166 | result = 1; |
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167 | call_cerror: |
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168 | _dl_signal_cerror (0, map->l_name[0] ? map->l_name : _dl_argv[0], NULL, |
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169 | errstring); |
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170 | return result; |
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171 | } |
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172 | |
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173 | |
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174 | int |
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175 | internal_function |
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176 | _dl_check_map_versions (struct link_map *map, int verbose, int trace_mode) |
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177 | { |
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178 | int result = 0; |
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179 | const char *strtab; |
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180 | /* Pointer to section with needed versions. */ |
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181 | ElfW(Dyn) *dyn; |
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182 | /* Pointer to dynamic section with definitions. */ |
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183 | ElfW(Dyn) *def; |
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184 | /* We need to find out which is the highest version index used |
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185 | in a dependecy. */ |
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186 | unsigned int ndx_high = 0; |
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187 | /* Initialize to make the compiler happy. */ |
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188 | const char *errstring = NULL; |
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189 | int errval = 0; |
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190 | |
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191 | /* If we don't have a string table, we must be ok. */ |
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192 | if (map->l_info[DT_STRTAB] == NULL) |
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193 | return 0; |
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194 | strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); |
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195 | |
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196 | dyn = map->l_info[VERSYMIDX (DT_VERNEED)]; |
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197 | def = map->l_info[VERSYMIDX (DT_VERDEF)]; |
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198 | |
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199 | if (dyn != NULL) |
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200 | { |
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201 | /* This file requires special versions from its dependencies. */ |
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202 | ElfW(Verneed) *ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr); |
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203 | |
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204 | /* Currently the version number of the needed entry is 1. |
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205 | Make sure all we see is this version. */ |
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206 | if (__builtin_expect (ent->vn_version, 1) != 1) |
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207 | { |
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208 | char buf[20]; |
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209 | buf[sizeof (buf) - 1] = '\0'; |
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210 | /* XXX We cannot translate the message. */ |
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211 | errstring = make_string ("unsupported version of Verneed record\n"); |
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212 | call_error: |
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213 | _dl_signal_error (errval, (*map->l_name ? map->l_name : _dl_argv[0]), |
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214 | NULL, errstring); |
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215 | } |
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216 | |
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217 | while (1) |
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218 | { |
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219 | ElfW(Vernaux) *aux; |
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220 | struct link_map *needed = find_needed (strtab + ent->vn_file, map); |
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221 | |
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222 | /* If NEEDED is NULL this means a dependency was not found |
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223 | and no stub entry was created. This should never happen. */ |
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224 | assert (needed != NULL); |
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225 | |
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226 | /* Make sure this is no stub we created because of a missing |
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227 | dependency. */ |
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228 | if (__builtin_expect (! trace_mode, 1) |
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229 | || ! __builtin_expect (needed->l_faked, 0)) |
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230 | { |
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231 | /* NEEDED is the map for the file we need. Now look for the |
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232 | dependency symbols. */ |
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233 | aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux); |
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234 | while (1) |
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235 | { |
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236 | /* Match the symbol. */ |
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237 | result |= match_symbol ((*map->l_name |
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238 | ? map->l_name : _dl_argv[0]), |
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239 | aux->vna_hash, |
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240 | strtab + aux->vna_name, |
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241 | needed, verbose, |
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242 | aux->vna_flags & VER_FLG_WEAK); |
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243 | |
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244 | /* Compare the version index. */ |
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245 | if ((unsigned int) (aux->vna_other & 0x7fff) > ndx_high) |
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246 | ndx_high = aux->vna_other & 0x7fff; |
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247 | |
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248 | if (aux->vna_next == 0) |
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249 | /* No more symbols. */ |
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250 | break; |
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251 | |
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252 | /* Next symbol. */ |
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253 | aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next); |
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254 | } |
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255 | } |
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256 | |
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257 | if (ent->vn_next == 0) |
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258 | /* No more dependencies. */ |
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259 | break; |
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260 | |
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261 | /* Next dependency. */ |
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262 | ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next); |
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263 | } |
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264 | } |
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265 | |
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266 | /* We also must store the names of the defined versions. Determine |
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267 | the maximum index here as well. |
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268 | |
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269 | XXX We could avoid the loop by just taking the number of definitions |
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270 | as an upper bound of new indeces. */ |
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271 | if (def != NULL) |
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272 | { |
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273 | ElfW(Verdef) *ent; |
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274 | ent = (ElfW(Verdef) *) (map->l_addr + def->d_un.d_ptr); |
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275 | while (1) |
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276 | { |
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277 | if ((unsigned int) (ent->vd_ndx & 0x7fff) > ndx_high) |
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278 | ndx_high = ent->vd_ndx & 0x7fff; |
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279 | |
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280 | if (ent->vd_next == 0) |
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281 | /* No more definitions. */ |
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282 | break; |
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283 | |
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284 | ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next); |
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285 | } |
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286 | } |
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287 | |
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288 | if (ndx_high > 0) |
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289 | { |
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290 | /* Now we are ready to build the array with the version names |
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291 | which can be indexed by the version index in the VERSYM |
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292 | section. */ |
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293 | map->l_versions = (struct r_found_version *) |
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294 | calloc (ndx_high + 1, sizeof (*map->l_versions)); |
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295 | if (__builtin_expect (map->l_versions == NULL, 0)) |
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296 | { |
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297 | errstring = N_("cannot allocate version reference table"); |
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298 | errval = ENOMEM; |
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299 | goto call_error; |
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300 | } |
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301 | |
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302 | /* Store the number of available symbols. */ |
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303 | map->l_nversions = ndx_high + 1; |
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304 | |
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305 | /* Compute the pointer to the version symbols. */ |
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306 | map->l_versyms = (void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); |
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307 | |
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308 | if (dyn != NULL) |
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309 | { |
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310 | ElfW(Verneed) *ent; |
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311 | ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr); |
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312 | while (1) |
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313 | { |
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314 | ElfW(Vernaux) *aux; |
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315 | aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux); |
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316 | while (1) |
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317 | { |
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318 | ElfW(Half) ndx = aux->vna_other & 0x7fff; |
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319 | map->l_versions[ndx].hash = aux->vna_hash; |
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320 | map->l_versions[ndx].hidden = aux->vna_other & 0x8000; |
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321 | map->l_versions[ndx].name = &strtab[aux->vna_name]; |
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322 | map->l_versions[ndx].filename = &strtab[ent->vn_file]; |
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323 | |
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324 | if (aux->vna_next == 0) |
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325 | /* No more symbols. */ |
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326 | break; |
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327 | |
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328 | /* Advance to next symbol. */ |
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329 | aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next); |
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330 | } |
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331 | |
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332 | if (ent->vn_next == 0) |
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333 | /* No more dependencies. */ |
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334 | break; |
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335 | |
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336 | /* Advance to next dependency. */ |
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337 | ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next); |
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338 | } |
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339 | } |
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340 | |
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341 | /* And insert the defined versions. */ |
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342 | if (def != NULL) |
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343 | { |
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344 | ElfW(Verdef) *ent; |
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345 | ent = (ElfW(Verdef) *) (map->l_addr + def->d_un.d_ptr); |
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346 | while (1) |
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347 | { |
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348 | ElfW(Verdaux) *aux; |
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349 | aux = (ElfW(Verdaux) *) ((char *) ent + ent->vd_aux); |
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350 | |
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351 | if ((ent->vd_flags & VER_FLG_BASE) == 0) |
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352 | { |
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353 | /* The name of the base version should not be |
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354 | available for matching a versioned symbol. */ |
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355 | ElfW(Half) ndx = ent->vd_ndx & 0x7fff; |
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356 | map->l_versions[ndx].hash = ent->vd_hash; |
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357 | map->l_versions[ndx].name = &strtab[aux->vda_name]; |
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358 | map->l_versions[ndx].filename = NULL; |
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359 | } |
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360 | |
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361 | if (ent->vd_next == 0) |
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362 | /* No more definitions. */ |
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363 | break; |
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364 | |
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365 | ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next); |
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366 | } |
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367 | } |
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368 | } |
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369 | |
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370 | return result; |
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371 | } |
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372 | |
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373 | |
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374 | int |
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375 | internal_function |
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376 | _dl_check_all_versions (struct link_map *map, int verbose, int trace_mode) |
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377 | { |
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378 | struct link_map *l; |
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379 | int result = 0; |
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380 | |
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381 | for (l = map; l != NULL; l = l->l_next) |
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382 | result |= ! l->l_faked && _dl_check_map_versions (l, verbose, trace_mode); |
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383 | |
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384 | return result; |
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385 | } |
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