1 | .\" Copyright (c) 2006-2008 Joseph Koshy. All rights reserved. |
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2 | .\" |
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3 | .\" Redistribution and use in source and binary forms, with or without |
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4 | .\" modification, are permitted provided that the following conditions |
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5 | .\" are met: |
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6 | .\" 1. Redistributions of source code must retain the above copyright |
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7 | .\" notice, this list of conditions and the following disclaimer. |
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8 | .\" 2. Redistributions in binary form must reproduce the above copyright |
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9 | .\" notice, this list of conditions and the following disclaimer in the |
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10 | .\" documentation and/or other materials provided with the distribution. |
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11 | .\" |
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12 | .\" This software is provided by Joseph Koshy ``as is'' and |
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13 | .\" any express or implied warranties, including, but not limited to, the |
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14 | .\" implied warranties of merchantability and fitness for a particular purpose |
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15 | .\" are disclaimed. in no event shall Joseph Koshy be liable |
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16 | .\" for any direct, indirect, incidental, special, exemplary, or consequential |
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17 | .\" damages (including, but not limited to, procurement of substitute goods |
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18 | .\" or services; loss of use, data, or profits; or business interruption) |
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19 | .\" however caused and on any theory of liability, whether in contract, strict |
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20 | .\" liability, or tort (including negligence or otherwise) arising in any way |
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21 | .\" out of the use of this software, even if advised of the possibility of |
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22 | .\" such damage. |
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23 | .\" |
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24 | .\" $Id: gelf_newehdr.3 189 2008-07-20 10:38:08Z jkoshy $ |
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25 | .\" |
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26 | .Dd October 22, 2007 |
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27 | .Os |
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28 | .Dt GELF_NEWEHDR 3 |
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29 | .Sh NAME |
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30 | .Nm elf32_newehdr , |
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31 | .Nm elf64_newehdr , |
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32 | .Nm gelf_newehdr |
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33 | .Nd retrieve or allocate the object file header |
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34 | .Sh LIBRARY |
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35 | .Lb libelf |
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36 | .Sh SYNOPSIS |
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37 | .In libelf.h |
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38 | .Ft "Elf32_Ehdr *" |
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39 | .Fn elf32_newehdr "Elf *elf" |
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40 | .Ft "Elf64_Ehdr *" |
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41 | .Fn elf64_newehdr "Elf *elf" |
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42 | .In gelf.h |
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43 | .Ft "void *" |
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44 | .Fn gelf_newehdr "Elf *elf" "int elfclass" |
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45 | .Sh DESCRIPTION |
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46 | These functions retrieve the ELF header from the ELF descriptor |
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47 | .Ar elf , |
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48 | allocating a new header if needed. |
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49 | File data structures are translated to their in-memory representations |
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50 | as described in |
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51 | .Xr elf 3 . |
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52 | .Pp |
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53 | Function |
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54 | .Fn elf32_newehdr |
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55 | returns a pointer to a 32 bit |
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56 | .Vt Elf32_Ehdr |
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57 | structure. |
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58 | Function |
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59 | .Fn elf64_newehdr |
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60 | returns a pointer to a 64 bit |
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61 | .Vt Elf64_Ehdr structure. |
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62 | .Pp |
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63 | When argument |
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64 | .Ar elfclass |
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65 | has value |
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66 | .Dv ELFCLASS32 , |
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67 | function |
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68 | .Fn gelf_newehdr |
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69 | returns the value returned by |
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70 | .Fn elf32_newehdr "elf" . |
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71 | When argument |
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72 | .Ar elfclass |
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73 | has value |
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74 | .Dv ELFCLASS64 |
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75 | it returns the value returned by |
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76 | .Fn elf64_newehdr "elf" . |
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77 | .Pp |
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78 | If a fresh header structure is allocated, the members of the |
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79 | structure are initialized as follows: |
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80 | .Bl -tag -width indent |
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81 | .It Va "e_ident[EI_MAG0..EI_MAG3]" |
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82 | Identification bytes at offsets |
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83 | .Dv EI_MAG0 , |
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84 | .Dv EI_MAG1 , |
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85 | .Dv EI_MAG2 |
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86 | and |
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87 | .Dv EI_MAG3 |
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88 | are set to the ELF signature. |
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89 | .It Va "e_ident[EI_CLASS]" |
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90 | The identification byte at offset |
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91 | .Dv EI_CLASS |
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92 | is set to the ELF class associated with the function being called |
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93 | or to argument |
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94 | .Ar elfclass |
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95 | for function |
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96 | .Fn gelf_newehdr . |
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97 | .It Va "e_ident[EI_DATA]" |
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98 | The identification byte at offset |
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99 | .Dv EI_DATA |
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100 | is set to |
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101 | .Dv ELFDATANONE . |
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102 | .It Va "e_ident[EI_VERSION]" |
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103 | The identification byte at offset |
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104 | .Dv EI_VERSION |
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105 | is set to the ELF library's operating version set by a prior call to |
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106 | .Xr elf_version 3 . |
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107 | .It Va e_machine |
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108 | is set to |
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109 | .Dv EM_NONE . |
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110 | .It Va e_type |
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111 | is set to |
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112 | .Dv ELF_K_NONE . |
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113 | .It Va e_version |
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114 | is set to the ELF library's operating version set by a prior call to |
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115 | .Xr elf_version 3 . |
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116 | .El |
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117 | .Pp |
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118 | Other members of the header are set to zero. |
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119 | The application is responsible for changing these values |
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120 | as needed before calling |
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121 | .Fn elf_update . |
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122 | .Pp |
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123 | If successful, these three functions set the |
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124 | .Dv ELF_F_DIRTY |
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125 | flag on ELF descriptor |
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126 | .Ar elf . |
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127 | .Sh RETURN VALUES |
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128 | These functions return a pointer to a translated header descriptor |
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129 | if successful, or NULL on failure. |
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130 | .Sh ERRORS |
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131 | These functions can fail with the following errors: |
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132 | .Bl -tag -width "[ELF_E_RESOURCE]" |
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133 | .It Bq Er ELF_E_ARGUMENT |
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134 | The argument |
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135 | .Ar elf |
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136 | was null. |
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137 | .It Bq Er ELF_E_ARGUMENT |
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138 | Argument |
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139 | .Ar elf |
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140 | was not a descriptor for an ELF object. |
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141 | .It Bq Er ELF_E_ARGUMENT |
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142 | Argument |
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143 | .Ar elfclass |
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144 | had an unsupported value. |
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145 | .It Bq Er ELF_E_ARGUMENT |
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146 | The class of the ELF descriptor |
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147 | .Ar elf |
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148 | did not match that of the requested operation. |
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149 | .It Bq Er ELF_E_ARGUMENT |
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150 | For function |
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151 | .Fn gelf_newehdr , |
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152 | the class of argument |
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153 | .Ar elf |
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154 | was not |
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155 | .Dv ELFCLASSNONE |
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156 | and did not match the argument |
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157 | .Ar elfclass . |
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158 | .It Bq Er ELF_E_CLASS |
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159 | The ELF class of descriptor |
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160 | .Ar elf |
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161 | did not match that of the API function being called. |
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162 | .It Bq Er ELF_E_HEADER |
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163 | A malformed ELF header was detected. |
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164 | .It Bq Er ELF_E_RESOURCE |
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165 | An out of memory condition was detected during execution. |
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166 | .It Bq Er ELF_E_SECTION |
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167 | The ELF descriptor in argument |
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168 | .Ar elf |
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169 | did not adhere to the conventions used for extended numbering. |
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170 | .It Bq Er ELF_E_VERSION |
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171 | The ELF descriptor |
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172 | .Ar elf |
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173 | had an unsupported ELF version number. |
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174 | .El |
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175 | .Sh SEE ALSO |
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176 | .Xr elf 3 , |
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177 | .Xr elf32_getehdr 3 , |
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178 | .Xr elf64_getehdr 3 , |
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179 | .Xr elf_flagdata 3 , |
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180 | .Xr elf_getident 3 , |
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181 | .Xr elf_update 3 , |
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182 | .Xr elf_version 3 , |
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183 | .Xr gelf 3 , |
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184 | .Xr gelf_getehdr 3 , |
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185 | .Xr elf 5 |
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