1 | /* |
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2 | * COPYRIGHT (c) 1989-2010. |
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3 | * On-Line Applications Research Corporation (OAR). |
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4 | * |
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5 | * The license and distribution terms for this file may be |
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6 | * found in the file LICENSE in this distribution or at |
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7 | * http://www.rtems.com/license/LICENSE. |
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8 | */ |
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9 | |
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10 | #if HAVE_CONFIG_H |
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11 | #include "config.h" |
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12 | #endif |
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13 | |
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14 | /* |
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15 | * This file implements the "mount" procedure for tar-based IMFS |
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16 | * extensions. The TAR is not actually mounted under the IMFS. |
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17 | * Directories from the TAR file are created as usual in the IMFS. |
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18 | * File entries are created as IMFS_LINEAR_FILE nodes with their nods |
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19 | * pointing to addresses in the TAR image. |
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20 | */ |
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21 | |
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22 | #include "imfs.h" |
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23 | |
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24 | #include <sys/stat.h> |
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25 | #include <string.h> |
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26 | #include <tar.h> |
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27 | |
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28 | #include <rtems/untar.h> |
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29 | |
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30 | /* |
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31 | * TAR file format: |
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32 | * |
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33 | * Offset Length Contents |
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34 | * 0 100 bytes File name ('\0' terminated, 99 maxmum length) |
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35 | * 100 8 bytes File mode (in octal ascii) |
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36 | * 108 8 bytes User ID (in octal ascii) |
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37 | * 116 8 bytes Group ID (in octal ascii) |
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38 | * 124 12 bytes File size (s) (in octal ascii) |
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39 | * 136 12 bytes Modify time (in octal ascii) |
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40 | * 148 8 bytes Header checksum (in octal ascii) |
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41 | * 156 1 bytes Link flag |
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42 | * 157 100 bytes Linkname ('\0' terminated, 99 maxmum length) |
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43 | * 257 8 bytes Magic PAX ("ustar\0" + 2 bytes padding) |
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44 | * 257 8 bytes Magic GNU tar ("ustar \0") |
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45 | * 265 32 bytes User name ('\0' terminated, 31 maxmum length) |
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46 | * 297 32 bytes Group name ('\0' terminated, 31 maxmum length) |
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47 | * 329 8 bytes Major device ID (in octal ascii) |
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48 | * 337 8 bytes Minor device ID (in octal ascii) |
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49 | * 345 167 bytes Padding |
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50 | * 512 (s+p)bytes File contents (s+p) := (((s) + 511) & ~511), |
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51 | * round up to 512 bytes |
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52 | * |
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53 | * Checksum: |
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54 | * int i, sum; |
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55 | * char* header = tar_header_pointer; |
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56 | * sum = 0; |
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57 | * for(i = 0; i < 512; i++) |
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58 | * sum += 0xFF & header[i]; |
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59 | */ |
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60 | |
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61 | #define MAX_NAME_FIELD_SIZE 99 |
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62 | |
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63 | #define MIN(a,b) ((a)>(b)?(b):(a)) |
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64 | |
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65 | /* |
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66 | * rtems_tarfs_load |
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67 | * |
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68 | * Here we create the mountpoint directory and load the tarfs at |
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69 | * that node. Once the IMFS has been mounted, we work through the |
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70 | * tar image and perform as follows: |
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71 | * - For directories, simply call mkdir(). The IMFS creates nodes as |
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72 | * needed. |
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73 | * - For files, we make our own calls to IMFS eval_for_make and |
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74 | * create_node. |
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75 | */ |
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76 | int rtems_tarfs_load( |
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77 | const char *mountpoint, |
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78 | uint8_t *tar_image, |
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79 | size_t tar_size |
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80 | ) |
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81 | { |
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82 | const char *hdr_ptr; |
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83 | char filename[100]; |
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84 | char full_filename[256]; |
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85 | int hdr_chksum; |
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86 | unsigned char linkflag; |
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87 | unsigned long file_size; |
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88 | unsigned long file_mode; |
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89 | int offset; |
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90 | unsigned long nblocks; |
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91 | IMFS_jnode_t *node; |
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92 | int rv = 0; |
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93 | int eval_flags = RTEMS_FS_FOLLOW_LINK; |
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94 | rtems_filesystem_eval_path_context_t ctx; |
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95 | rtems_filesystem_location_info_t rootloc; |
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96 | rtems_filesystem_location_info_t *currentloc = |
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97 | rtems_filesystem_eval_path_start( &ctx, mountpoint, eval_flags ); |
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98 | |
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99 | rtems_filesystem_eval_path_extract_currentloc( &ctx, &rootloc ); |
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100 | rtems_filesystem_eval_path_set_flags( |
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101 | &ctx, |
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102 | RTEMS_FS_MAKE | RTEMS_FS_EXCLUSIVE |
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103 | ); |
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104 | |
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105 | if ( |
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106 | rootloc.mt_entry->ops != &IMFS_ops |
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107 | && rootloc.mt_entry->ops != &fifoIMFS_ops |
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108 | ) { |
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109 | rv = -1; |
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110 | } |
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111 | |
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112 | /* |
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113 | * Create an IMFS node structure pointing to tar image memory. |
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114 | */ |
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115 | offset = 0; |
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116 | while ( rv == 0 ) { |
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117 | if (offset + 512 > tar_size) |
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118 | break; |
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119 | |
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120 | /* |
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121 | * Read a header. |
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122 | */ |
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123 | hdr_ptr = (char *) &tar_image[offset]; |
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124 | offset += 512; |
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125 | if (strncmp(&hdr_ptr[257], "ustar", 5)) |
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126 | break; |
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127 | |
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128 | strncpy(filename, hdr_ptr, MAX_NAME_FIELD_SIZE); |
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129 | filename[MAX_NAME_FIELD_SIZE] = '\0'; |
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130 | |
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131 | linkflag = hdr_ptr[156]; |
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132 | file_mode = _rtems_octal2ulong(&hdr_ptr[100], 8); |
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133 | file_size = _rtems_octal2ulong(&hdr_ptr[124], 12); |
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134 | hdr_chksum = _rtems_octal2ulong(&hdr_ptr[148], 8); |
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135 | |
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136 | if (_rtems_tar_header_checksum(hdr_ptr) != hdr_chksum) |
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137 | break; |
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138 | |
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139 | /* |
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140 | * Generate an IMFS node depending on the file type. |
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141 | * - For directories, just create directories as usual. IMFS |
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142 | * will take care of the rest. |
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143 | * - For files, create a file node with special tarfs properties. |
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144 | */ |
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145 | if (linkflag == DIRTYPE) { |
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146 | strcpy(full_filename, mountpoint); |
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147 | if (full_filename[strlen(full_filename)-1] != '/') |
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148 | strcat(full_filename, "/"); |
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149 | strcat(full_filename, filename); |
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150 | mkdir(full_filename, S_IRWXU | S_IRWXG | S_IRWXO); |
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151 | } |
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152 | /* |
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153 | * Create a LINEAR_FILE node |
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154 | */ |
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155 | else if (linkflag == REGTYPE) { |
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156 | rtems_filesystem_location_free( currentloc ); |
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157 | rtems_filesystem_location_clone( currentloc, &rootloc ); |
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158 | rtems_filesystem_eval_path_set_path( |
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159 | &ctx, |
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160 | filename, |
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161 | strlen( filename ) |
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162 | ); |
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163 | rtems_filesystem_eval_path_continue( &ctx ); |
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164 | |
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165 | if ( !rtems_filesystem_location_is_null( currentloc ) ) { |
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166 | node = IMFS_create_node( |
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167 | currentloc, |
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168 | IMFS_LINEAR_FILE, |
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169 | rtems_filesystem_eval_path_get_token( &ctx ), |
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170 | rtems_filesystem_eval_path_get_tokenlen( &ctx ), |
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171 | (file_mode & (S_IRWXU | S_IRWXG | S_IRWXO)) | S_IFREG, |
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172 | NULL |
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173 | ); |
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174 | node->info.linearfile.size = file_size; |
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175 | node->info.linearfile.direct = &tar_image[offset]; |
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176 | } |
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177 | |
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178 | nblocks = (((file_size) + 511) & ~511) / 512; |
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179 | offset += 512 * nblocks; |
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180 | } |
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181 | } |
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182 | |
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183 | rtems_filesystem_location_free( &rootloc ); |
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184 | rtems_filesystem_eval_path_cleanup( &ctx ); |
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185 | |
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186 | return rv; |
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187 | } |
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188 | |
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