1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Mini dd implementation for busybox
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4 | *
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5 | *
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6 | * Copyright (C) 2000,2001 Matt Kraai
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7 | *
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8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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9 | */
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10 |
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11 | //usage:#define dd_trivial_usage
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12 | //usage: "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
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13 | //usage: " [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync]")
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14 | //usage:#define dd_full_usage "\n\n"
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15 | //usage: "Copy a file with converting and formatting\n"
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16 | //usage: "\n if=FILE Read from FILE instead of stdin"
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17 | //usage: "\n of=FILE Write to FILE instead of stdout"
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18 | //usage: "\n bs=N Read and write N bytes at a time"
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19 | //usage: IF_FEATURE_DD_IBS_OBS(
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20 | //usage: "\n ibs=N Read N bytes at a time"
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21 | //usage: )
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22 | //usage: IF_FEATURE_DD_IBS_OBS(
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23 | //usage: "\n obs=N Write N bytes at a time"
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24 | //usage: )
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25 | //usage: "\n count=N Copy only N input blocks"
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26 | //usage: "\n skip=N Skip N input blocks"
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27 | //usage: "\n seek=N Skip N output blocks"
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28 | //usage: IF_FEATURE_DD_IBS_OBS(
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29 | //usage: "\n conv=notrunc Don't truncate output file"
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30 | //usage: "\n conv=noerror Continue after read errors"
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31 | //usage: "\n conv=sync Pad blocks with zeros"
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32 | //usage: "\n conv=fsync Physically write data out before finishing"
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33 | //usage: )
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34 | //usage: "\n"
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35 | //usage: "\nNumbers may be suffixed by c (x1), w (x2), b (x512), kD (x1000), k (x1024),"
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36 | //usage: "\nMD (x1000000), M (x1048576), GD (x1000000000) or G (x1073741824)"
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37 | //usage:
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38 | //usage:#define dd_example_usage
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39 | //usage: "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
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40 | //usage: "4+0 records in\n"
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41 | //usage: "4+0 records out\n"
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42 |
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43 | #include "libbb.h"
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44 |
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45 | /* This is a NOEXEC applet. Be very careful! */
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46 |
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47 |
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48 | enum {
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49 | ifd = STDIN_FILENO,
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50 | ofd = STDOUT_FILENO,
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51 | };
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52 |
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53 | static const struct suffix_mult dd_suffixes[] = {
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54 | { "c", 1 },
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55 | { "w", 2 },
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56 | { "b", 512 },
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57 | { "kD", 1000 },
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58 | { "k", 1024 },
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59 | { "K", 1024 }, /* compat with coreutils dd */
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60 | { "MD", 1000000 },
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61 | { "M", 1048576 },
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62 | { "GD", 1000000000 },
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63 | { "G", 1073741824 },
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64 | { "", 0 }
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65 | };
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66 |
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67 | struct globals {
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68 | off_t out_full, out_part, in_full, in_part;
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69 | #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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70 | unsigned long long total_bytes;
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71 | unsigned long long begin_time_us;
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72 | #endif
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73 | } FIX_ALIASING;
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74 | #define G (*(struct globals*)&bb_common_bufsiz1)
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75 | #define INIT_G() do { \
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76 | /* we have to zero it out because of NOEXEC */ \
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77 | memset(&G, 0, sizeof(G)); \
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78 | } while (0)
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79 |
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80 |
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81 | static void dd_output_status(int UNUSED_PARAM cur_signal)
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82 | {
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83 | #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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84 | double seconds;
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85 | unsigned long long bytes_sec;
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86 | unsigned long long now_us = monotonic_us(); /* before fprintf */
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87 | #endif
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88 |
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89 | /* Deliberately using %u, not %d */
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90 | fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
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91 | "%"OFF_FMT"u+%"OFF_FMT"u records out\n",
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92 | G.in_full, G.in_part,
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93 | G.out_full, G.out_part);
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94 |
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95 | #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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96 | fprintf(stderr, "%llu bytes (%sB) copied, ",
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97 | G.total_bytes,
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98 | /* show fractional digit, use suffixes */
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99 | make_human_readable_str(G.total_bytes, 1, 0)
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100 | );
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101 | /* Corner cases:
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102 | * ./busybox dd </dev/null >/dev/null
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103 | * ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
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104 | * (echo DONE) | ./busybox dd >/dev/null
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105 | * (sleep 1; echo DONE) | ./busybox dd >/dev/null
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106 | */
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107 | seconds = (now_us - G.begin_time_us) / 1000000.0;
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108 | bytes_sec = G.total_bytes / seconds;
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109 | fprintf(stderr, "%f seconds, %sB/s\n",
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110 | seconds,
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111 | /* show fractional digit, use suffixes */
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112 | make_human_readable_str(bytes_sec, 1, 0)
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113 | );
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114 | #endif
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115 | }
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116 |
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117 | static ssize_t full_write_or_warn(const void *buf, size_t len,
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118 | const char *const filename)
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119 | {
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120 | ssize_t n = full_write(ofd, buf, len);
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121 | if (n < 0)
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122 | bb_perror_msg("writing '%s'", filename);
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123 | return n;
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124 | }
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125 |
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126 | static bool write_and_stats(const void *buf, size_t len, size_t obs,
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127 | const char *filename)
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128 | {
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129 | ssize_t n = full_write_or_warn(buf, len, filename);
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130 | if (n < 0)
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131 | return 1;
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132 | if ((size_t)n == obs)
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133 | G.out_full++;
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134 | else if (n) /* > 0 */
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135 | G.out_part++;
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136 | #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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137 | G.total_bytes += n;
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138 | #endif
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139 | return 0;
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140 | }
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141 |
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142 | #if ENABLE_LFS
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143 | # define XATOU_SFX xatoull_sfx
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144 | #else
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145 | # define XATOU_SFX xatoul_sfx
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146 | #endif
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147 |
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148 | int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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149 | int dd_main(int argc UNUSED_PARAM, char **argv)
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150 | {
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151 | enum {
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152 | /* Must be in the same order as OP_conv_XXX! */
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153 | /* (see "flags |= (1 << what)" below) */
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154 | FLAG_NOTRUNC = 1 << 0,
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155 | FLAG_SYNC = 1 << 1,
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156 | FLAG_NOERROR = 1 << 2,
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157 | FLAG_FSYNC = 1 << 3,
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158 | /* end of conv flags */
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159 | FLAG_TWOBUFS = 1 << 4,
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160 | FLAG_COUNT = 1 << 5,
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161 | };
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162 | static const char keywords[] ALIGN1 =
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163 | "bs\0""count\0""seek\0""skip\0""if\0""of\0"
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164 | #if ENABLE_FEATURE_DD_IBS_OBS
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165 | "ibs\0""obs\0""conv\0"
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166 | #endif
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167 | ;
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168 | #if ENABLE_FEATURE_DD_IBS_OBS
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169 | static const char conv_words[] ALIGN1 =
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170 | "notrunc\0""sync\0""noerror\0""fsync\0";
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171 | #endif
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172 | enum {
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173 | OP_bs = 0,
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174 | OP_count,
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175 | OP_seek,
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176 | OP_skip,
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177 | OP_if,
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178 | OP_of,
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179 | #if ENABLE_FEATURE_DD_IBS_OBS
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180 | OP_ibs,
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181 | OP_obs,
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182 | OP_conv,
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183 | /* Must be in the same order as FLAG_XXX! */
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184 | OP_conv_notrunc = 0,
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185 | OP_conv_sync,
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186 | OP_conv_noerror,
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187 | OP_conv_fsync,
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188 | /* Unimplemented conv=XXX: */
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189 | //nocreat do not create the output file
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190 | //excl fail if the output file already exists
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191 | //fdatasync physically write output file data before finishing
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192 | //swab swap every pair of input bytes
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193 | //lcase change upper case to lower case
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194 | //ucase change lower case to upper case
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195 | //block pad newline-terminated records with spaces to cbs-size
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196 | //unblock replace trailing spaces in cbs-size records with newline
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197 | //ascii from EBCDIC to ASCII
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198 | //ebcdic from ASCII to EBCDIC
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199 | //ibm from ASCII to alternate EBCDIC
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200 | #endif
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201 | };
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202 | int exitcode = EXIT_FAILURE;
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203 | size_t ibs = 512, obs = 512;
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204 | ssize_t n, w;
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205 | char *ibuf, *obuf;
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206 | /* And these are all zeroed at once! */
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207 | struct {
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208 | int flags;
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209 | size_t oc;
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210 | off_t count;
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211 | off_t seek, skip;
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212 | const char *infile, *outfile;
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213 | } Z;
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214 | #define flags (Z.flags )
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215 | #define oc (Z.oc )
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216 | #define count (Z.count )
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217 | #define seek (Z.seek )
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218 | #define skip (Z.skip )
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219 | #define infile (Z.infile )
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220 | #define outfile (Z.outfile)
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221 |
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222 | memset(&Z, 0, sizeof(Z));
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223 | INIT_G();
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224 | //fflush_all(); - is this needed because of NOEXEC?
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225 |
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226 | for (n = 1; argv[n]; n++) {
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227 | int what;
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228 | char *val;
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229 | char *arg = argv[n];
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230 |
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231 | #if ENABLE_DESKTOP
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232 | /* "dd --". NB: coreutils 6.9 will complain if they see
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233 | * more than one of them. We wouldn't. */
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234 | if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
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235 | continue;
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236 | #endif
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237 | val = strchr(arg, '=');
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238 | if (val == NULL)
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239 | bb_show_usage();
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240 | *val = '\0';
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241 | what = index_in_strings(keywords, arg);
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242 | if (what < 0)
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243 | bb_show_usage();
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244 | /* *val = '='; - to preserve ps listing? */
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245 | val++;
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246 | #if ENABLE_FEATURE_DD_IBS_OBS
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247 | if (what == OP_ibs) {
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248 | /* Must fit into positive ssize_t */
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249 | ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
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250 | /*continue;*/
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251 | }
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252 | if (what == OP_obs) {
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253 | obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
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254 | /*continue;*/
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255 | }
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256 | if (what == OP_conv) {
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257 | while (1) {
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258 | /* find ',', replace them with NUL so we can use val for
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259 | * index_in_strings() without copying.
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260 | * We rely on val being non-null, else strchr would fault.
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261 | */
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262 | arg = strchr(val, ',');
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263 | if (arg)
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264 | *arg = '\0';
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265 | what = index_in_strings(conv_words, val);
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266 | if (what < 0)
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267 | bb_error_msg_and_die(bb_msg_invalid_arg, val, "conv");
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268 | flags |= (1 << what);
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269 | if (!arg) /* no ',' left, so this was the last specifier */
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270 | break;
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271 | /* *arg = ','; - to preserve ps listing? */
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272 | val = arg + 1; /* skip this keyword and ',' */
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273 | }
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274 | continue; /* we trashed 'what', can't fall through */
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275 | }
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276 | #endif
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277 | if (what == OP_bs) {
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278 | ibs = obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
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279 | /*continue;*/
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280 | }
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281 | /* These can be large: */
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282 | if (what == OP_count) {
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283 | flags |= FLAG_COUNT;
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284 | count = XATOU_SFX(val, dd_suffixes);
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285 | /*continue;*/
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286 | }
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287 | if (what == OP_seek) {
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288 | seek = XATOU_SFX(val, dd_suffixes);
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289 | /*continue;*/
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290 | }
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291 | if (what == OP_skip) {
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292 | skip = XATOU_SFX(val, dd_suffixes);
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293 | /*continue;*/
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294 | }
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295 | if (what == OP_if) {
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296 | infile = val;
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297 | /*continue;*/
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298 | }
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299 | if (what == OP_of) {
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300 | outfile = val;
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301 | /*continue;*/
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302 | }
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303 | } /* end of "for (argv[n])" */
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304 |
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305 | //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
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306 | ibuf = obuf = xmalloc(ibs);
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307 | if (ibs != obs) {
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308 | flags |= FLAG_TWOBUFS;
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309 | obuf = xmalloc(obs);
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310 | }
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311 |
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312 | #if ENABLE_FEATURE_DD_SIGNAL_HANDLING
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313 | signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
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314 | #endif
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315 | #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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316 | G.begin_time_us = monotonic_us();
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317 | #endif
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318 |
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319 | if (infile != NULL)
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320 | xmove_fd(xopen(infile, O_RDONLY), ifd);
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321 | else {
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322 | infile = bb_msg_standard_input;
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323 | }
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324 | if (outfile != NULL) {
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325 | int oflag = O_WRONLY | O_CREAT;
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326 |
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327 | if (!seek && !(flags & FLAG_NOTRUNC))
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328 | oflag |= O_TRUNC;
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329 |
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330 | xmove_fd(xopen(outfile, oflag), ofd);
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331 |
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332 | if (seek && !(flags & FLAG_NOTRUNC)) {
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333 | if (ftruncate(ofd, seek * obs) < 0) {
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334 | struct stat st;
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335 |
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336 | if (fstat(ofd, &st) < 0
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337 | || S_ISREG(st.st_mode)
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338 | || S_ISDIR(st.st_mode)
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339 | ) {
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340 | goto die_outfile;
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341 | }
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342 | }
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343 | }
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344 | } else {
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345 | outfile = bb_msg_standard_output;
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346 | }
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347 | if (skip) {
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348 | if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
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349 | while (skip-- > 0) {
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350 | n = safe_read(ifd, ibuf, ibs);
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351 | if (n < 0)
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352 | goto die_infile;
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353 | if (n == 0)
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354 | break;
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355 | }
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356 | }
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357 | }
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358 | if (seek) {
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359 | if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
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360 | goto die_outfile;
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361 | }
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362 |
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363 | while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
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364 | n = safe_read(ifd, ibuf, ibs);
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365 | if (n == 0)
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366 | break;
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367 | if (n < 0) {
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368 | /* "Bad block" */
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369 | if (!(flags & FLAG_NOERROR))
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370 | goto die_infile;
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371 | bb_simple_perror_msg(infile);
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372 | /* GNU dd with conv=noerror skips over bad blocks */
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373 | xlseek(ifd, ibs, SEEK_CUR);
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374 | /* conv=noerror,sync writes NULs,
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375 | * conv=noerror just ignores input bad blocks */
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376 | n = 0;
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377 | }
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378 | if ((size_t)n == ibs)
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379 | G.in_full++;
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380 | else {
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381 | G.in_part++;
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382 | if (flags & FLAG_SYNC) {
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383 | memset(ibuf + n, 0, ibs - n);
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384 | n = ibs;
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385 | }
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386 | }
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387 | if (flags & FLAG_TWOBUFS) {
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388 | char *tmp = ibuf;
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389 | while (n) {
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390 | size_t d = obs - oc;
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391 |
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392 | if (d > (size_t)n)
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393 | d = n;
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394 | memcpy(obuf + oc, tmp, d);
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395 | n -= d;
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396 | tmp += d;
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397 | oc += d;
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398 | if (oc == obs) {
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399 | if (write_and_stats(obuf, obs, obs, outfile))
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400 | goto out_status;
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401 | oc = 0;
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402 | }
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403 | }
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404 | } else if (write_and_stats(ibuf, n, obs, outfile))
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405 | goto out_status;
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406 |
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407 | if (flags & FLAG_FSYNC) {
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408 | if (fsync(ofd) < 0)
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409 | goto die_outfile;
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410 | }
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411 | }
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412 |
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413 | if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
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414 | w = full_write_or_warn(obuf, oc, outfile);
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415 | if (w < 0) goto out_status;
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416 | if (w > 0) G.out_part++;
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417 | }
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418 | if (close(ifd) < 0) {
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419 | die_infile:
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420 | bb_simple_perror_msg_and_die(infile);
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421 | }
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422 |
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423 | if (close(ofd) < 0) {
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424 | die_outfile:
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425 | bb_simple_perror_msg_and_die(outfile);
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426 | }
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427 |
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428 | exitcode = EXIT_SUCCESS;
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429 | out_status:
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430 | dd_output_status(0);
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431 |
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432 | if (ENABLE_FEATURE_CLEAN_UP) {
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433 | free(obuf);
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434 | if (flags & FLAG_TWOBUFS)
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435 | free(ibuf);
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436 | }
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437 |
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438 | return exitcode;
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439 | }
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