1 | /* FIXME: |
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2 | * 1. Symbolic links are not created. |
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3 | * 2. Untar_FromMemory has printfs. |
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4 | * 3. Untar_FromMemory uses FILE *fp. |
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5 | * 4. How to determine end of archive? |
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6 | * |
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7 | * Written by: Jake Janovetz <janovetz@tempest.ece.uiuc.edu> |
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8 | * |
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9 | * The license and distribution terms for this file may be |
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10 | * found in the file LICENSE in this distribution or at |
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11 | * http://www.OARcorp.com/rtems/license.html. |
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12 | * |
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13 | * $Id$ |
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14 | */ |
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15 | |
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16 | #include <stdio.h> |
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17 | #include <string.h> |
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18 | #include <stdlib.h> |
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19 | #include <unistd.h> |
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20 | #include <fcntl.h> |
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21 | #include "untar.h" |
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22 | |
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23 | |
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24 | /************************************************************************** |
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25 | * TAR file format: |
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26 | * |
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27 | * Offset Length Contents |
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28 | * 0 100 bytes File name ('\0' terminated, 99 maxmum length) |
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29 | * 100 8 bytes File mode (in octal ascii) |
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30 | * 108 8 bytes User ID (in octal ascii) |
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31 | * 116 8 bytes Group ID (in octal ascii) |
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32 | * 124 12 bytes File size (s) (in octal ascii) |
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33 | * 136 12 bytes Modify time (in octal ascii) |
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34 | * 148 8 bytes Header checksum (in octal ascii) |
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35 | * 156 1 bytes Link flag |
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36 | * 157 100 bytes Linkname ('\0' terminated, 99 maxmum length) |
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37 | * 257 8 bytes Magic ("ustar \0") |
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38 | * 265 32 bytes User name ('\0' terminated, 31 maxmum length) |
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39 | * 297 32 bytes Group name ('\0' terminated, 31 maxmum length) |
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40 | * 329 8 bytes Major device ID (in octal ascii) |
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41 | * 337 8 bytes Minor device ID (in octal ascii) |
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42 | * 345 167 bytes Padding |
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43 | * 512 (s+p)bytes File contents (s+p) := (((s) + 511) & ~511), |
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44 | * round up to 512 bytes |
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45 | * |
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46 | * Checksum: |
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47 | * int i, sum; |
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48 | * char* header = tar_header_pointer; |
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49 | * sum = 0; |
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50 | * for(i = 0; i < 512; i++) |
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51 | * sum += 0xFF & header[i]; |
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52 | *************************************************************************/ |
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53 | |
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54 | #define LF_OLDNORMAL '\0' /* Normal disk file, Unix compatible */ |
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55 | #define LF_NORMAL '0' /* Normal disk file */ |
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56 | #define LF_LINK '1' /* Link to previously dumped file */ |
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57 | #define LF_SYMLINK '2' /* Symbolic link */ |
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58 | #define LF_CHR '3' /* Character special file */ |
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59 | #define LF_BLK '4' /* Block special file */ |
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60 | #define LF_DIR '5' /* Directory */ |
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61 | #define LF_FIFO '6' /* FIFO special file */ |
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62 | #define LF_CONFIG '7' /* Contiguous file */ |
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63 | |
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64 | #define MAX_NAME_FIELD_SIZE 99 |
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65 | |
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66 | #define MIN(a,b) ((a)>(b)?(b):(a)) |
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67 | |
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68 | |
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69 | /************************************************************************** |
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70 | * This converts octal ASCII number representations into an |
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71 | * unsigned long. Only support 32-bit numbers for now. |
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72 | *************************************************************************/ |
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73 | static unsigned long |
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74 | octal2ulong(char *octascii, int len) |
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75 | { |
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76 | int i; |
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77 | unsigned long num; |
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78 | unsigned long mult; |
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79 | |
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80 | num = 0; |
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81 | mult = 1; |
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82 | for (i=len-1; i>=0; i--) |
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83 | { |
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84 | if ((octascii[i] < '0') || (octascii[i] > '9')) |
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85 | { |
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86 | continue; |
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87 | } |
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88 | num += mult*((unsigned long)(octascii[i] - '0')); |
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89 | mult *= 8; |
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90 | } |
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91 | return(num); |
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92 | } |
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93 | |
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94 | |
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95 | /************************************************************************** |
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96 | * Function: Untar_FromMemory * |
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97 | ************************************************************************** |
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98 | * Description: * |
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99 | * * |
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100 | * This is a simple subroutine used to rip links, directories, and * |
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101 | * files out of a block of memory. * |
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102 | * * |
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103 | * * |
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104 | * Inputs: * |
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105 | * * |
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106 | * unsigned char *tar_buf - Pointer to TAR buffer. * |
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107 | * unsigned long size - Length of TAR buffer. * |
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108 | * * |
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109 | * * |
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110 | * Output: * |
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111 | * * |
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112 | * int - UNTAR_SUCCESSFUL (0) on successful completion. * |
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113 | * UNTAR_INVALID_CHECKSUM for an invalid header checksum. * |
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114 | * UNTAR_INVALID_HEADER for an invalid header. * |
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115 | * * |
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116 | ************************************************************************** |
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117 | * Change History: * |
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118 | * 12/30/1998 - Creation (JWJ) * |
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119 | *************************************************************************/ |
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120 | int |
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121 | Untar_FromMemory(unsigned char *tar_buf, unsigned long size) |
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122 | { |
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123 | FILE *fp; |
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124 | char *bufr; |
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125 | size_t n; |
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126 | char fname[100]; |
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127 | char linkname[100]; |
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128 | int sum; |
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129 | int hdr_chksum; |
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130 | int retval; |
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131 | unsigned long ptr; |
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132 | unsigned long i; |
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133 | unsigned long nblocks; |
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134 | unsigned long file_size; |
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135 | unsigned char linkflag; |
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136 | |
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137 | |
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138 | ptr = 0; |
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139 | while (1) |
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140 | { |
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141 | if (ptr + 512 > size) |
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142 | { |
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143 | retval = UNTAR_SUCCESSFUL; |
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144 | break; |
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145 | } |
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146 | |
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147 | /* Read the header */ |
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148 | bufr = &tar_buf[ptr]; |
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149 | ptr += 512; |
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150 | if (strncmp(&bufr[257], "ustar ", 7)) |
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151 | { |
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152 | retval = UNTAR_SUCCESSFUL; |
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153 | break; |
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154 | } |
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155 | |
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156 | strncpy(fname, bufr, MAX_NAME_FIELD_SIZE); |
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157 | fname[MAX_NAME_FIELD_SIZE] = '\0'; |
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158 | |
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159 | linkflag = bufr[156]; |
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160 | file_size = octal2ulong(&bufr[124], 12); |
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161 | |
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162 | /****************************************************************** |
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163 | * Compute the TAR checksum and check with the value in |
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164 | * the archive. The checksum is computed over the entire |
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165 | * header, but the checksum field is substituted with blanks. |
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166 | ******************************************************************/ |
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167 | hdr_chksum = (int)octal2ulong(&bufr[148], 8); |
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168 | sum = 0; |
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169 | for (i=0; i<512; i++) |
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170 | { |
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171 | if ((i >= 148) && (i < 156)) |
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172 | { |
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173 | sum += 0xff & ' '; |
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174 | } |
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175 | else |
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176 | { |
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177 | sum += 0xff & bufr[i]; |
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178 | } |
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179 | } |
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180 | if (sum != hdr_chksum) |
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181 | { |
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182 | retval = UNTAR_INVALID_CHECKSUM; |
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183 | break; |
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184 | } |
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185 | |
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186 | |
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187 | /****************************************************************** |
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188 | * We've decoded the header, now figure out what it contains and |
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189 | * do something with it. |
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190 | *****************************************************************/ |
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191 | if (linkflag == LF_SYMLINK) |
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192 | { |
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193 | strncpy(linkname, &bufr[157], MAX_NAME_FIELD_SIZE); |
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194 | linkname[MAX_NAME_FIELD_SIZE] = '\0'; |
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195 | /* symlink(fname, linkname); */ |
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196 | } |
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197 | else if (linkflag == LF_NORMAL) |
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198 | { |
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199 | nblocks = (((file_size) + 511) & ~511) / 512; |
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200 | if ((fp = fopen(fname, "w")) == NULL) |
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201 | { |
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202 | printf("Untar failed to create file %s\n", fname); |
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203 | ptr += 512 * nblocks; |
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204 | } |
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205 | else |
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206 | { |
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207 | unsigned long sizeToGo = file_size; |
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208 | unsigned long len; |
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209 | |
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210 | /*************************************************************** |
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211 | * Read out the data. There are nblocks of data where nblocks |
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212 | * is the file_size rounded to the nearest 512-byte boundary. |
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213 | **************************************************************/ |
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214 | for (i=0; i<nblocks; i++) |
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215 | { |
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216 | len = ((sizeToGo < 512L)?(sizeToGo):(512L)); |
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217 | n = fwrite(&tar_buf[ptr], 1, len, fp); |
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218 | if (n != len) |
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219 | { |
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220 | printf("Error during write\n"); |
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221 | break; |
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222 | } |
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223 | ptr += 512; |
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224 | sizeToGo -= n; |
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225 | } |
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226 | fclose(fp); |
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227 | } |
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228 | } |
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229 | else if (linkflag == LF_DIR) |
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230 | { |
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231 | mkdir(fname, S_IRWXU | S_IRWXG | S_IRWXO); |
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232 | } |
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233 | } |
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234 | |
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235 | return(retval); |
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236 | } |
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237 | |
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238 | |
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239 | /************************************************************************** |
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240 | * Function: Untar_FromFile * |
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241 | ************************************************************************** |
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242 | * Description: * |
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243 | * * |
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244 | * This is a simple subroutine used to rip links, directories, and * |
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245 | * files out of a TAR file. * |
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246 | * * |
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247 | * * |
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248 | * Inputs: * |
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249 | * * |
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250 | * char *tar_name - TAR filename. * |
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251 | * * |
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252 | * * |
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253 | * Output: * |
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254 | * * |
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255 | * int - UNTAR_SUCCESSFUL (0) on successful completion. * |
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256 | * UNTAR_INVALID_CHECKSUM for an invalid header checksum. * |
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257 | * UNTAR_INVALID_HEADER for an invalid header. * |
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258 | * * |
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259 | ************************************************************************** |
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260 | * Change History: * |
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261 | * 12/30/1998 - Creation (JWJ) * |
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262 | *************************************************************************/ |
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263 | int |
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264 | Untar_FromFile(char *tar_name) |
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265 | { |
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266 | int fd; |
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267 | char *bufr; |
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268 | size_t n; |
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269 | char fname[100]; |
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270 | char linkname[100]; |
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271 | int sum; |
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272 | int hdr_chksum; |
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273 | int retval; |
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274 | unsigned long i; |
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275 | unsigned long nblocks; |
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276 | unsigned long size; |
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277 | unsigned char linkflag; |
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278 | |
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279 | |
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280 | retval = UNTAR_SUCCESSFUL; |
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281 | bufr = (char *)malloc(512); |
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282 | if (bufr == NULL) |
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283 | { |
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284 | return(UNTAR_FAIL); |
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285 | } |
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286 | |
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287 | fd = open(tar_name, O_RDONLY); |
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288 | while (1) |
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289 | { |
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290 | /* Read the header */ |
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291 | /* If the header read fails, we just consider it the end |
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292 | of the tarfile. */ |
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293 | if ((n = read(fd, bufr, 512)) != 512) |
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294 | { |
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295 | break; |
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296 | } |
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297 | |
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298 | if (strncmp(&bufr[257], "ustar ", 7)) |
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299 | { |
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300 | break; |
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301 | } |
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302 | |
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303 | strncpy(fname, bufr, MAX_NAME_FIELD_SIZE); |
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304 | fname[MAX_NAME_FIELD_SIZE] = '\0'; |
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305 | |
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306 | linkflag = bufr[156]; |
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307 | size = octal2ulong(&bufr[124], 12); |
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308 | |
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309 | /****************************************************************** |
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310 | * Compute the TAR checksum and check with the value in |
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311 | * the archive. The checksum is computed over the entire |
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312 | * header, but the checksum field is substituted with blanks. |
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313 | ******************************************************************/ |
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314 | hdr_chksum = (int)octal2ulong(&bufr[148], 8); |
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315 | sum = 0; |
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316 | for (i=0; i<512; i++) |
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317 | { |
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318 | if ((i >= 148) && (i < 156)) |
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319 | { |
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320 | sum += 0xff & ' '; |
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321 | } |
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322 | else |
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323 | { |
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324 | sum += 0xff & bufr[i]; |
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325 | } |
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326 | } |
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327 | if (sum != hdr_chksum) |
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328 | { |
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329 | retval = UNTAR_INVALID_CHECKSUM; |
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330 | break; |
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331 | } |
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332 | |
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333 | |
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334 | /****************************************************************** |
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335 | * We've decoded the header, now figure out what it contains and |
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336 | * do something with it. |
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337 | *****************************************************************/ |
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338 | if (linkflag == LF_SYMLINK) |
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339 | { |
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340 | strncpy(linkname, &bufr[157], MAX_NAME_FIELD_SIZE); |
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341 | linkname[MAX_NAME_FIELD_SIZE] = '\0'; |
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342 | } |
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343 | else if (linkflag == LF_NORMAL) |
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344 | { |
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345 | int out_fd; |
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346 | |
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347 | /****************************************************************** |
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348 | * Read out the data. There are nblocks of data where nblocks |
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349 | * is the size rounded to the nearest 512-byte boundary. |
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350 | *****************************************************************/ |
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351 | nblocks = (((size) + 511) & ~511) / 512; |
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352 | |
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353 | if ((out_fd = creat(fname, 0644)) == -1) |
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354 | { |
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355 | for (i=0; i<nblocks; i++) |
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356 | { |
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357 | n = read(fd, bufr, 512); |
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358 | } |
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359 | } |
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360 | else |
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361 | { |
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362 | for (i=0; i<nblocks; i++) |
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363 | { |
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364 | n = read(fd, bufr, 512); |
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365 | n = MIN(n, size - i*512); |
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366 | write(out_fd, bufr, n); |
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367 | } |
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368 | close(out_fd); |
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369 | } |
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370 | } |
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371 | else if (linkflag == LF_DIR) |
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372 | { |
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373 | mkdir(fname, S_IRWXU | S_IRWXG | S_IRWXO); |
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374 | } |
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375 | } |
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376 | free(bufr); |
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377 | close(fd); |
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378 | |
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379 | return(retval); |
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380 | } |
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381 | |
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