1 | /*
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2 | * blockdev implementation for busybox
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3 | *
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4 | * Copyright (C) 2010 Sergey Naumov <sknaumov@gmail.com>
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5 | *
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6 | * Licensed under GPLv2, see file LICENSE in this source tree.
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7 | */
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8 |
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9 | //applet:IF_BLOCKDEV(APPLET(blockdev, _BB_DIR_SBIN, _BB_SUID_DROP))
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10 |
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11 | //kbuild:lib-$(CONFIG_BLOCKDEV) += blockdev.o
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12 |
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13 | //config:config BLOCKDEV
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14 | //config: bool "blockdev"
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15 | //config: default y
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16 | //config: help
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17 | //config: Performs some ioctls with block devices.
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18 |
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19 | //usage:#define blockdev_trivial_usage
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20 | //usage: "OPTION BLOCKDEV"
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21 | //usage:#define blockdev_full_usage "\n\n"
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22 | //usage: "Options:"
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23 | //usage: "\n --setro Set ro"
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24 | //usage: "\n --setrw Set rw"
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25 | //usage: "\n --getro Get ro"
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26 | //usage: "\n --getss Get sector size"
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27 | //usage: "\n --getbsz Get block size"
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28 | //usage: "\n --setbsz BYTES Set block size"
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29 | //usage: "\n --getsize Get device size in 512-byte sectors"
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30 | //usage: "\n --getsize64 Get device size in bytes"
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31 | //usage: "\n --flushbufs Flush buffers"
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32 | //usage: "\n --rereadpt Reread partition table"
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33 |
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34 |
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35 | #include "libbb.h"
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36 | #include <linux/fs.h>
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37 |
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38 | /* Patch bco to compile this busybox on rhel3 */
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39 | #ifndef BLKGETSIZE64
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40 | #define BLKGETSIZE64 _IOR(0x12,114,size_t)
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41 | #endif
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42 |
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43 | enum {
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44 | ARG_NONE = 0,
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45 | ARG_INT = 1,
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46 | ARG_ULONG = 2,
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47 | /* Yes, BLKGETSIZE64 takes pointer to uint64_t, not ullong! */
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48 | ARG_U64 = 3,
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49 | ARG_MASK = 3,
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50 |
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51 | FL_USRARG = 4, /* argument is provided by user */
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52 | FL_NORESULT = 8,
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53 | };
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54 |
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55 | struct bdc {
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56 | uint32_t ioc; /* ioctl code */
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57 | const char name[sizeof("flushbufs")]; /* "--setfoo" wothout "--" */
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58 | uint8_t flags;
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59 | int8_t argval; /* default argument value */
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60 | };
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61 |
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62 | static const struct bdc bdcommands[] = {
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63 | {
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64 | .ioc = BLKROSET,
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65 | .name = "setro",
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66 | .flags = ARG_INT + FL_NORESULT,
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67 | .argval = 1,
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68 | },{
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69 | .ioc = BLKROSET,
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70 | .name = "setrw",
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71 | .flags = ARG_INT + FL_NORESULT,
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72 | .argval = 0,
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73 | },{
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74 | .ioc = BLKROGET,
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75 | .name = "getro",
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76 | .flags = ARG_INT,
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77 | .argval = -1,
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78 | },{
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79 | .ioc = BLKSSZGET,
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80 | .name = "getss",
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81 | .flags = ARG_INT,
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82 | .argval = -1,
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83 | },{
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84 | .ioc = BLKBSZGET,
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85 | .name = "getbsz",
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86 | .flags = ARG_INT,
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87 | .argval = -1,
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88 | },{
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89 | .ioc = BLKBSZSET,
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90 | .name = "setbsz",
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91 | .flags = ARG_INT + FL_NORESULT + FL_USRARG,
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92 | .argval = 0,
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93 | },{
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94 | .ioc = BLKGETSIZE,
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95 | .name = "getsize",
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96 | .flags = ARG_ULONG,
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97 | .argval = -1,
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98 | },{
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99 | .ioc = BLKGETSIZE64,
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100 | .name = "getsize64",
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101 | .flags = ARG_U64,
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102 | .argval = -1,
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103 | },{
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104 | .ioc = BLKFLSBUF,
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105 | .name = "flushbufs",
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106 | .flags = ARG_NONE + FL_NORESULT,
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107 | .argval = 0,
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108 | },{
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109 | .ioc = BLKRRPART,
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110 | .name = "rereadpt",
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111 | .flags = ARG_NONE + FL_NORESULT,
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112 | .argval = 0,
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113 | }
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114 | };
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115 |
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116 | static const struct bdc *find_cmd(const char *s)
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117 | {
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118 | const struct bdc *bdcmd = bdcommands;
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119 | if (s[0] == '-' && s[1] == '-') {
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120 | s += 2;
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121 | do {
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122 | if (strcmp(s, bdcmd->name) == 0)
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123 | return bdcmd;
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124 | bdcmd++;
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125 | } while (bdcmd != bdcommands + ARRAY_SIZE(bdcommands));
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126 | }
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127 | bb_show_usage();
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128 | }
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129 |
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130 | int blockdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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131 | int blockdev_main(int argc, char **argv)
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132 | {
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133 | const struct bdc *bdcmd;
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134 | int fd;
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135 | uint64_t u64;
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136 | union {
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137 | int i;
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138 | unsigned long lu;
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139 | uint64_t u64;
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140 | } ioctl_val_on_stack;
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141 |
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142 | if ((unsigned)(argc - 3) > 1) /* must have 2 or 3 args */
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143 | bb_show_usage();
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144 |
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145 | bdcmd = find_cmd(*++argv);
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146 |
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147 | u64 = (int)bdcmd->argval;
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148 | if (bdcmd->flags & FL_USRARG)
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149 | u64 = xatoi_positive(*++argv);
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150 |
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151 | if (!*++argv || argv[1])
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152 | bb_show_usage();
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153 | fd = xopen(*argv, O_RDONLY);
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154 |
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155 | ioctl_val_on_stack.u64 = u64;
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156 | #if BB_BIG_ENDIAN
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157 | /* Store data properly wrt data size.
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158 | * (1) It's no-op for little-endian.
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159 | * (2) it's no-op for 0 and -1. Only --setro uses arg != 0 and != -1,
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160 | * and it is ARG_INT. --setbsz USER_VAL is also ARG_INT.
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161 | * Thus, we don't need to handle ARG_ULONG.
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162 | */
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163 | switch (bdcmd->flags & ARG_MASK) {
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164 | case ARG_INT:
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165 | ioctl_val_on_stack.i = (int)u64;
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166 | break;
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167 | # if 0 /* unused */
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168 | case ARG_ULONG:
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169 | ioctl_val_on_stack.lu = (unsigned long)u64;
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170 | break;
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171 | # endif
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172 | }
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173 | #endif
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174 |
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175 | if (ioctl(fd, bdcmd->ioc, &ioctl_val_on_stack.u64) == -1)
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176 | bb_simple_perror_msg_and_die(*argv);
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177 |
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178 | /* Fetch it into register(s) */
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179 | u64 = ioctl_val_on_stack.u64;
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180 |
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181 | /* Zero- or one-extend the value if needed, then print */
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182 | switch (bdcmd->flags & (ARG_MASK+FL_NORESULT)) {
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183 | case ARG_INT:
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184 | /* Smaller code when we use long long
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185 | * (gcc tail-merges printf call)
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186 | */
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187 | printf("%lld\n", (long long)(int)u64);
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188 | break;
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189 | case ARG_ULONG:
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190 | u64 = (unsigned long)u64;
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191 | /* FALLTHROUGH */
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192 | case ARG_U64:
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193 | printf("%llu\n", (unsigned long long)u64);
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194 | break;
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195 | }
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196 |
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197 | if (ENABLE_FEATURE_CLEAN_UP)
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198 | close(fd);
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199 | return EXIT_SUCCESS;
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200 | }
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