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_xlatetof.3 189 2008-07-20 10:38:08Z jkoshy $ |
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25 | .\" |
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26 | .Dd July 24, 2006 |
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27 | .Os |
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28 | .Dt GELF_XLATETOF 3 |
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29 | .Sh NAME |
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30 | .Nm elf32_xlate , |
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31 | .Nm elf64_xlate , |
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32 | .Nm gelf_xlate |
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33 | .Nd translate data between files and memory |
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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 "Elf_Data *" |
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39 | .Fn elf32_xlatetof "Elf_Data *dst" "Elf_Data *src" "unsigned int encode" |
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40 | .Ft "Elf_Data *" |
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41 | .Fn elf32_xlatetom "Elf_Data *dst" "Elf_Data *src" "unsigned int encode" |
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42 | .Ft "Elf_Data *" |
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43 | .Fn elf64_xlatetof "Elf_Data *dst" "Elf_Data *src" "unsigned int encode" |
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44 | .Ft "Elf_Data *" |
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45 | .Fn elf64_xlatetom "Elf_Data *dst" "Elf_Data *src" "unsigned int encode" |
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46 | .In gelf.h |
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47 | .Ft "Elf_Data *" |
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48 | .Fo gelf_xlatetof |
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49 | .Fa "Elf *elf" |
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50 | .Fa "Elf_Data *dst" |
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51 | .Fa "Elf_Data *src" |
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52 | .Fa "unsigned int encode" |
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53 | .Fc |
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54 | .Ft "Elf_Data *" |
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55 | .Fo gelf_xlatetom |
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56 | .Fa "Elf *elf" |
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57 | .Fa "Elf_Data *dst" |
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58 | .Fa "Elf_Data *src" |
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59 | .Fa "unsigned int encode" |
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60 | .Fc |
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61 | .Sh DESCRIPTION |
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62 | These functions translate between the file and memory representations |
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63 | of ELF data structures. |
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64 | The in-memory representation of an ELF data structure would confirm to |
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65 | the byte ordering and data alignment restrictions dictated by the host |
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66 | processor. |
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67 | A file representation of the same data structure could use a non-native byte |
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68 | ordering and in addition may be laid out differently with the file. |
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69 | .Pp |
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70 | Functions |
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71 | .Fn elf32_xlatetom , |
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72 | .Fn elf64_xlatetom , |
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73 | and |
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74 | .Fn gelf_xlatetom |
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75 | translate data from file representations to native, in-memory representations. |
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76 | Functions |
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77 | .Fn elf32_xlatetof , |
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78 | .Fn elf64_xlatetof , |
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79 | and |
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80 | .Fn gelf_xlatetof |
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81 | translate data from in-memory representations to file representations. |
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82 | .Pp |
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83 | Argument |
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84 | .Ar src |
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85 | denotes an |
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86 | .Vt Elf_Data |
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87 | descriptor describing the source to be translated. |
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88 | The following elements of the descriptor need to be set before |
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89 | invoking these functions: |
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90 | .Bl -hang -offset indent |
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91 | .It Va d_buf |
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92 | Set to a valid pointer value denoting the beginning of the data area |
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93 | to be translated. |
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94 | .It Va d_size |
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95 | Set to the total size in bytes of the source data area to be |
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96 | translated. |
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97 | .It Va d_type |
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98 | Set to the type of the source data being translated. |
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99 | This value is one of the values defined in the |
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100 | .Vt Elf_Type |
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101 | enumeration. |
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102 | The |
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103 | .Vt Elf_Type |
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104 | enumeration is described in |
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105 | .Xr elf 3 . |
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106 | .It Va d_version |
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107 | Set to the version number of the ELF data structures being |
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108 | translated. |
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109 | Currently only version |
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110 | .Dv EV_CURRENT |
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111 | is supported. |
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112 | .El |
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113 | .Pp |
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114 | Argument |
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115 | .Ar dst |
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116 | describes the destination buffer. |
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117 | The following elements of the |
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118 | .Vt Elf_Data |
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119 | descriptor need to be set before invoking these functions: |
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120 | .Bl -hang -offset indent |
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121 | .It Va d_buf |
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122 | Set to a valid pointer value that denotes the start of the destination |
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123 | buffer that will hold translated data. |
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124 | This value may be the same as that of the source buffer, in which case |
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125 | an in-place conversion will be attempted. |
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126 | .It Va d_size |
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127 | Set to the size of the destination buffer in bytes. |
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128 | This value will be modified if the function call succeeds. |
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129 | .It Va d_version |
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130 | Set to the desired version number of the destination. |
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131 | Currently only version |
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132 | .Dv EV_CURRENT |
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133 | is supported. |
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134 | .El |
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135 | .Pp |
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136 | These translations routines allow the source and destination buffers |
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137 | to coincide, in which case an in-place translation will be done |
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138 | if the destination is large enough to hold the translated data. |
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139 | Other kinds of overlap between the source and destination buffers |
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140 | are not permitted. |
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141 | .Pp |
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142 | On successful completion of the translation request the following |
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143 | fields of the |
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144 | .Ar dst |
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145 | descriptor would be modified: |
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146 | .Bl -hang -offset indent |
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147 | .It Va d_size |
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148 | Set to the size in bytes of the translated data. |
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149 | .It Va d_type |
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150 | Set to the |
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151 | .Va d_type |
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152 | value of the source data descriptor. |
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153 | .El |
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154 | .Pp |
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155 | Argument |
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156 | .Ar encode |
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157 | specifies the encoding in which the file objects are represented. |
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158 | It must be one of: |
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159 | .Bl -hang -offset indent |
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160 | .It Dv ELFDATANONE |
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161 | File objects use the library's native byte ordering. |
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162 | .It Dv ELFDATA2LSB |
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163 | File objects use a little-endian ordering. |
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164 | .It Dv ELFDATA2MSB |
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165 | File objects use a big-endian ordering. |
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166 | .El |
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167 | .Pp |
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168 | The functions |
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169 | .Fn gelf_xlatetof |
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170 | and |
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171 | .Fn gelf_xlatetom |
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172 | select the appropriate 32 or 64 bit translations based on the class of argument |
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173 | .Ar elf . |
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174 | .Sh RETURN VALUES |
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175 | These functions return argument |
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176 | .Ar dst |
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177 | if successful, or NULL in case of an error. |
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178 | .Sh EXAMPLES |
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179 | TODO |
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180 | .Sh ERRORS |
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181 | These functions may fail with the following errors: |
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182 | .Bl -tag -width "[ELF_E_RESOURCE]" |
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183 | .It Bq Er ELF_E_ARGUMENT |
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184 | One of arguments |
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185 | .Ar src , |
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186 | .Ar dst |
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187 | or |
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188 | .Ar elf |
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189 | was NULL. |
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190 | .It Bq Er ELF_E_ARGUMENT |
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191 | Arguments |
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192 | .Ar src |
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193 | and |
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194 | .Ar dst |
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195 | were equal. |
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196 | .It Bq Er ELF_E_ARGUMENT |
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197 | The desired encoding parameter was not one of |
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198 | .Dv ELFDATANONE , |
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199 | .Dv ELFDATA2LSB |
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200 | or |
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201 | .Dv ELFDATA2MSB . |
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202 | .It Bq Er ELF_E_ARGUMENT |
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203 | The |
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204 | .Ar d_type |
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205 | field of argument |
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206 | .Ar src |
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207 | specified an unsupported type. |
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208 | .It Bq Er ELF_E_DATA |
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209 | The |
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210 | .Ar src |
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211 | argument specified a buffer size that was not an integral multiple of |
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212 | its underlying type. |
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213 | .It Bq Er ELF_E_DATA |
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214 | The |
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215 | .Ar dst |
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216 | argument specified a buffer size that was too small. |
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217 | .It Bq Er ELF_E_DATA |
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218 | Argument |
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219 | .Ar dst |
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220 | specified a destination buffer that overlaps with the source |
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221 | buffer. |
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222 | .It Bq Er ELF_E_DATA |
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223 | The destination buffer for a conversion to memory had an alignment |
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224 | inappropriate for the underlying ELF type. |
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225 | .It Bq Er ELF_E_DATA |
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226 | The source buffer for a conversion to file had an alignment |
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227 | inappropriate for the underlying ELF type. |
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228 | .It Bq Er ELF_E_UNIMPL |
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229 | The version numbers for arguments |
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230 | .Ar dst |
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231 | and |
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232 | .Ar src |
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233 | were not identical. |
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234 | .It Bq Er ELF_E_UNIMPL |
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235 | The argument |
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236 | .Ar src |
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237 | requested conversion for a type which is not currently |
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238 | supported. |
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239 | .It Bq Er ELF_E_VERSION |
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240 | Argument |
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241 | .Ar src |
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242 | specified an unsupported version number. |
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243 | .El |
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244 | .Sh SEE ALSO |
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245 | .Xr elf 3 , |
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246 | .Xr elf_getdata 3 , |
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247 | .Xr gelf 3 |
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