1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * getsize.c --- get the size of a partition.
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4 | *
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5 | * Copyright (C) 1995, 1995 Theodore Ts'o.
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6 | *
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7 | * %Begin-Header%
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8 | * This file may be redistributed under the terms of the
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9 | * GNU Lesser General Public License.
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10 | * %End-Header%
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11 | */
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12 |
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13 | /* include this before sys/queues.h! */
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14 | #include "blkidP.h"
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15 |
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16 | #include <stdio.h>
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17 | #include <unistd.h>
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18 | #ifdef HAVE_ERRNO_H
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19 | #include <errno.h>
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20 | #endif
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21 | #include <fcntl.h>
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22 | #ifdef HAVE_SYS_IOCTL_H
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23 | #include <sys/ioctl.h>
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24 | #endif
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25 | #ifdef HAVE_LINUX_FD_H
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26 | #include <linux/fd.h>
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27 | #endif
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28 | #ifdef HAVE_SYS_DISKLABEL_H
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29 | #include <sys/disklabel.h>
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30 | #include <sys/stat.h>
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31 | #endif
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32 | #ifdef HAVE_SYS_DISK_H
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33 | #ifdef HAVE_SYS_QUEUE_H
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34 | #include <sys/queue.h> /* for LIST_HEAD */
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35 | #endif
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36 | #include <sys/disk.h>
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37 | #endif
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38 | #ifdef __linux__
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39 | #include <sys/utsname.h>
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40 | #endif
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41 |
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42 | #if defined(__linux__) && defined(_IO) && !defined(BLKGETSIZE)
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43 | #define BLKGETSIZE _IO(0x12,96) /* return device size */
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44 | #endif
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45 |
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46 | #if defined(__linux__) && defined(_IOR) && !defined(BLKGETSIZE64)
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47 | #define BLKGETSIZE64 _IOR(0x12,114,size_t) /* return device size in bytes (u64 *arg) */
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48 | #endif
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49 |
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50 | #ifdef APPLE_DARWIN
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51 | #define BLKGETSIZE DKIOCGETBLOCKCOUNT32
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52 | #endif /* APPLE_DARWIN */
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53 |
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54 | static int valid_offset(int fd, blkid_loff_t offset)
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55 | {
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56 | char ch;
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57 |
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58 | if (blkid_llseek(fd, offset, 0) < 0)
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59 | return 0;
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60 | if (read(fd, &ch, 1) < 1)
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61 | return 0;
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62 | return 1;
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63 | }
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64 |
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65 | /*
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66 | * Returns the number of blocks in a partition
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67 | */
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68 | blkid_loff_t blkid_get_dev_size(int fd)
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69 | {
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70 | int valid_blkgetsize64 = 1;
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71 | #ifdef __linux__
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72 | struct utsname ut;
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73 | #endif
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74 | unsigned long long size64;
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75 | unsigned long size;
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76 | blkid_loff_t high, low;
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77 | #ifdef FDGETPRM
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78 | struct floppy_struct this_floppy;
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79 | #endif
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80 | #ifdef HAVE_SYS_DISKLABEL_H
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81 | int part = -1;
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82 | struct disklabel lab;
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83 | struct partition *pp;
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84 | char ch;
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85 | struct stat st;
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86 | #endif /* HAVE_SYS_DISKLABEL_H */
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87 |
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88 | #ifdef DKIOCGETBLOCKCOUNT /* For Apple Darwin */
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89 | if (ioctl(fd, DKIOCGETBLOCKCOUNT, &size64) >= 0) {
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90 | if ((sizeof(blkid_loff_t) < sizeof(unsigned long long))
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91 | && (size64 << 9 > 0xFFFFFFFF))
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92 | return 0; /* EFBIG */
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93 | return (blkid_loff_t) size64 << 9;
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94 | }
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95 | #endif
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96 |
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97 | #ifdef BLKGETSIZE64
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98 | #ifdef __linux__
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99 | if ((uname(&ut) == 0) &&
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100 | ((ut.release[0] == '2') && (ut.release[1] == '.') &&
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101 | (ut.release[2] < '6') && (ut.release[3] == '.')))
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102 | valid_blkgetsize64 = 0;
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103 | #endif
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104 | if (valid_blkgetsize64 &&
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105 | ioctl(fd, BLKGETSIZE64, &size64) >= 0) {
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106 | if ((sizeof(blkid_loff_t) < sizeof(unsigned long long))
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107 | && ((size64) > 0xFFFFFFFF))
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108 | return 0; /* EFBIG */
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109 | return size64;
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110 | }
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111 | #endif
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112 |
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113 | #ifdef BLKGETSIZE
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114 | if (ioctl(fd, BLKGETSIZE, &size) >= 0)
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115 | return (blkid_loff_t)size << 9;
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116 | #endif
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117 |
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118 | #ifdef FDGETPRM
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119 | if (ioctl(fd, FDGETPRM, &this_floppy) >= 0)
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120 | return (blkid_loff_t)this_floppy.size << 9;
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121 | #endif
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122 | #ifdef HAVE_SYS_DISKLABEL_H
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123 | #if 0
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124 | /*
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125 | * This should work in theory but I haven't tested it. Anyone
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126 | * on a BSD system want to test this for me? In the meantime,
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127 | * binary search mechanism should work just fine.
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128 | */
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129 | if ((fstat(fd, &st) >= 0) && S_ISBLK(st.st_mode))
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130 | part = st.st_rdev & 7;
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131 | if (part >= 0 && (ioctl(fd, DIOCGDINFO, (char *)&lab) >= 0)) {
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132 | pp = &lab.d_partitions[part];
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133 | if (pp->p_size)
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134 | return pp->p_size << 9;
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135 | }
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136 | #endif
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137 | #endif /* HAVE_SYS_DISKLABEL_H */
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138 |
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139 | /*
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140 | * OK, we couldn't figure it out by using a specialized ioctl,
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141 | * which is generally the best way. So do binary search to
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142 | * find the size of the partition.
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143 | */
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144 | low = 0;
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145 | for (high = 1024; valid_offset(fd, high); high *= 2)
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146 | low = high;
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147 | while (low < high - 1)
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148 | {
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149 | const blkid_loff_t mid = (low + high) / 2;
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150 |
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151 | if (valid_offset(fd, mid))
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152 | low = mid;
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153 | else
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154 | high = mid;
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155 | }
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156 | return low + 1;
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157 | }
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158 |
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159 | #ifdef TEST_PROGRAM
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160 | int main(int argc, char **argv)
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161 | {
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162 | blkid_loff_t bytes;
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163 | int fd;
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164 |
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165 | if (argc < 2) {
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166 | fprintf(stderr, "Usage: %s device\n"
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167 | "Determine the size of a device\n", argv[0]);
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168 | return 1;
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169 | }
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170 |
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171 | if ((fd = open(argv[1], O_RDONLY)) < 0)
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172 | perror(argv[0]);
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173 |
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174 | bytes = blkid_get_dev_size(fd);
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175 | printf("Device %s has %lld 1k blocks.\n", argv[1], bytes >> 10);
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176 |
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177 | return 0;
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178 | }
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179 | #endif
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