1 /* 2 * getsize.c --- get the size of a partition. 3 * 4 * Copyright (C) 1995, 1995 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the 8 * GNU Lesser General Public License. 9 * %End-Header% 10 */ 11 12 #ifndef _LARGEFILE_SOURCE 13 #define _LARGEFILE_SOURCE 14 #endif 15 #ifndef _LARGEFILE64_SOURCE 16 #define _LARGEFILE64_SOURCE 17 #endif 18 19 #include "config.h" 20 #include "blkidP.h" 21 22 #include <stdio.h> 23 #if HAVE_UNISTD_H 24 #include <unistd.h> 25 #endif 26 #if HAVE_ERRNO_H 27 #include <errno.h> 28 #endif 29 #include <fcntl.h> 30 #ifdef HAVE_SYS_IOCTL_H 31 #include <sys/ioctl.h> 32 #endif 33 #ifdef HAVE_LINUX_FD_H 34 #include <linux/fd.h> 35 #endif 36 #ifdef HAVE_SYS_DISKLABEL_H 37 #include <sys/disklabel.h> 38 #endif 39 #ifdef HAVE_SYS_DISK_H 40 #include <sys/disk.h> 41 #endif 42 #ifdef __linux__ 43 #include <sys/utsname.h> 44 #endif 45 #if HAVE_SYS_STAT_H 46 #include <sys/stat.h> 47 #endif 48 49 50 #if defined(__linux__) && defined(_IO) && !defined(BLKGETSIZE) 51 #define BLKGETSIZE _IO(0x12,96) /* return device size */ 52 #endif 53 54 #if defined(__linux__) && defined(_IOR) && !defined(BLKGETSIZE64) 55 #define BLKGETSIZE64 _IOR(0x12,114,size_t) /* return device size in bytes (u64 *arg) */ 56 #endif 57 58 #ifdef APPLE_DARWIN 59 #define BLKGETSIZE DKIOCGETBLOCKCOUNT32 60 #endif /* APPLE_DARWIN */ 61 62 static int valid_offset(int fd, blkid_loff_t offset) 63 { 64 char ch; 65 66 if (blkid_llseek(fd, offset, 0) < 0) 67 return 0; 68 if (read(fd, &ch, 1) < 1) 69 return 0; 70 return 1; 71 } 72 73 /* 74 * Returns the number of bytes in a partition 75 */ 76 blkid_loff_t blkid_get_dev_size(int fd) 77 { 78 unsigned long long size64; 79 blkid_loff_t high, low; 80 81 #if defined DKIOCGETBLOCKCOUNT && defined DKIOCGETBLOCKSIZE /* For Apple Darwin */ 82 unsigned int size; 83 84 if (ioctl(fd, DKIOCGETBLOCKCOUNT, &size64) >= 0 && 85 ioctl(fd, DKIOCGETBLOCKSIZE, &size) >= 0) { 86 if (sizeof(blkid_loff_t) < sizeof(unsigned long long) && 87 (size64 * size) > 0xFFFFFFFF) 88 return 0; /* EFBIG */ 89 return (blkid_loff_t)size64 * size; 90 } 91 #endif 92 93 #ifdef BLKGETSIZE64 94 { 95 int valid_blkgetsize64 = 1; 96 #ifdef __linux__ 97 struct utsname ut; 98 99 if ((uname(&ut) == 0) && 100 ((ut.release[0] == '2') && (ut.release[1] == '.') && 101 (ut.release[2] < '6') && (ut.release[3] == '.'))) 102 valid_blkgetsize64 = 0; 103 #endif 104 if (valid_blkgetsize64 && 105 ioctl(fd, BLKGETSIZE64, &size64) >= 0) { 106 if (sizeof(blkid_loff_t) < sizeof(unsigned long long) && 107 (size64 > 0xFFFFFFFF)) 108 return 0; /* EFBIG */ 109 return size64; 110 } 111 } 112 #endif /* BLKGETSIZE64 */ 113 114 #ifdef BLKGETSIZE 115 { 116 unsigned long size; 117 118 if (ioctl(fd, BLKGETSIZE, &size) >= 0) 119 return (blkid_loff_t)size << 9; 120 } 121 #endif 122 123 /* tested on FreeBSD 6.1-RELEASE i386 */ 124 #ifdef DIOCGMEDIASIZE 125 if (ioctl(fd, DIOCGMEDIASIZE, &size64) >= 0) 126 return (off_t)size64; 127 #endif /* DIOCGMEDIASIZE */ 128 129 #ifdef FDGETPRM 130 { 131 struct floppy_struct this_floppy; 132 133 if (ioctl(fd, FDGETPRM, &this_floppy) >= 0) 134 return (blkid_loff_t)this_floppy.size << 9; 135 } 136 #endif 137 #if defined(HAVE_SYS_DISKLABEL_H) && defined(DIOCGDINFO) 138 { 139 int part = -1; 140 struct disklabel lab; 141 struct partition *pp; 142 char ch; 143 struct stat st; 144 145 /* 146 * This code works for FreeBSD 4.11 i386, except for the full 147 * device (such as /dev/ad0). It doesn't work properly for 148 * newer FreeBSD though. FreeBSD >= 5.0 should be covered by 149 * the DIOCGMEDIASIZE above however. 150 * 151 * Note that FreeBSD >= 4.0 has disk devices as unbuffered (raw, 152 * character) devices, so we need to check for S_ISCHR, too. 153 */ 154 if (fstat(fd, &st) >= 0 && 155 blkidP_is_disk_device(st.st_mode)) 156 part = st.st_rdev & 7; 157 158 if (part >= 0 && (ioctl(fd, DIOCGDINFO, (char *)&lab) >= 0)) { 159 pp = &lab.d_partitions[part]; 160 if (pp->p_size) 161 return pp->p_size << 9; 162 } 163 } 164 #endif /* defined(HAVE_SYS_DISKLABEL_H) && defined(DIOCGDINFO) */ 165 { 166 #if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED) 167 struct stat64 st; 168 if (fstat64(fd, &st) == 0) 169 #else 170 struct stat st; 171 if (fstat(fd, &st) == 0) 172 #endif 173 if (S_ISREG(st.st_mode)) 174 return st.st_size; 175 } 176 177 /* 178 * OK, we couldn't figure it out by using a specialized ioctl, 179 * which is generally the best way. So do binary search to 180 * find the size of the partition. 181 */ 182 low = 0; 183 for (high = 1024; valid_offset(fd, high); high *= 2) 184 low = high; 185 while (low < high - 1) { 186 const blkid_loff_t mid = (low + high) / 2; 187 188 if (valid_offset(fd, mid)) 189 low = mid; 190 else 191 high = mid; 192 } 193 return low + 1; 194 } 195 196 #ifdef TEST_PROGRAM 197 int main(int argc, char **argv) 198 { 199 long long bytes; 200 int fd; 201 202 if (argc < 2) { 203 fprintf(stderr, "Usage: %s device\n" 204 "Determine the size of a device\n", argv[0]); 205 return 1; 206 } 207 208 if ((fd = open(argv[1], O_RDONLY)) < 0) 209 perror(argv[0]); 210 211 bytes = blkid_get_dev_size(fd); 212 printf("Device %s has %lld 1k blocks.\n", argv[1], 213 (unsigned long long)bytes >> 10); 214 215 return 0; 216 } 217 #endif