getsize.c revision de8f3a76218255e443ba57dec5d74850180fa75d
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#define _LARGEFILE_SOURCE 13#define _LARGEFILE64_SOURCE 14 15/* include this before sys/queues.h! */ 16#include "blkidP.h" 17 18#include <stdio.h> 19#if HAVE_UNISTD_H 20#include <unistd.h> 21#endif 22#if HAVE_ERRNO_H 23#include <errno.h> 24#endif 25#include <fcntl.h> 26#ifdef HAVE_SYS_IOCTL_H 27#include <sys/ioctl.h> 28#endif 29#ifdef HAVE_LINUX_FD_H 30#include <linux/fd.h> 31#endif 32#ifdef HAVE_SYS_DISKLABEL_H 33#include <sys/disklabel.h> 34#endif 35#ifdef HAVE_SYS_DISK_H 36#ifdef HAVE_SYS_QUEUE_H 37#include <sys/queue.h> /* for LIST_HEAD */ 38#endif 39#include <sys/disk.h> 40#endif 41#ifdef __linux__ 42#include <sys/utsname.h> 43#endif 44#if HAVE_SYS_STAT_H 45#include <sys/stat.h> 46#endif 47 48 49#if defined(__linux__) && defined(_IO) && !defined(BLKGETSIZE) 50#define BLKGETSIZE _IO(0x12,96) /* return device size */ 51#endif 52 53#if defined(__linux__) && defined(_IOR) && !defined(BLKGETSIZE64) 54#define BLKGETSIZE64 _IOR(0x12,114,size_t) /* return device size in bytes (u64 *arg) */ 55#endif 56 57#ifdef APPLE_DARWIN 58#define BLKGETSIZE DKIOCGETBLOCKCOUNT32 59#endif /* APPLE_DARWIN */ 60 61static int valid_offset(int fd, blkid_loff_t offset) 62{ 63 char ch; 64 65 if (blkid_llseek(fd, offset, 0) < 0) 66 return 0; 67 if (read(fd, &ch, 1) < 1) 68 return 0; 69 return 1; 70} 71 72/* 73 * Returns the number of bytes in a partition 74 */ 75blkid_loff_t blkid_get_dev_size(int fd) 76{ 77 int valid_blkgetsize64 = 1; 78#ifdef __linux__ 79 struct utsname ut; 80#endif 81 unsigned long long size64; 82 unsigned long size; 83 blkid_loff_t high, low; 84#ifdef FDGETPRM 85 struct floppy_struct this_floppy; 86#endif 87#ifdef HAVE_SYS_DISKLABEL_H 88 int part = -1; 89 struct disklabel lab; 90 struct partition *pp; 91 char ch; 92 struct stat st; 93#endif /* HAVE_SYS_DISKLABEL_H */ 94 95#ifdef DKIOCGETBLOCKCOUNT /* For Apple Darwin */ 96 if (ioctl(fd, DKIOCGETBLOCKCOUNT, &size64) >= 0) { 97 if ((sizeof(blkid_loff_t) < sizeof(unsigned long long)) 98 && (size64 << 9 > 0xFFFFFFFF)) 99 return 0; /* EFBIG */ 100 return (blkid_loff_t) size64 << 9; 101 } 102#endif 103 104#ifdef BLKGETSIZE64 105#ifdef __linux__ 106 if ((uname(&ut) == 0) && 107 ((ut.release[0] == '2') && (ut.release[1] == '.') && 108 (ut.release[2] < '6') && (ut.release[3] == '.'))) 109 valid_blkgetsize64 = 0; 110#endif 111 if (valid_blkgetsize64 && 112 ioctl(fd, BLKGETSIZE64, &size64) >= 0) { 113 if ((sizeof(blkid_loff_t) < sizeof(unsigned long long)) 114 && ((size64) > 0xFFFFFFFF)) 115 return 0; /* EFBIG */ 116 return size64; 117 } 118#endif 119 120#ifdef BLKGETSIZE 121 if (ioctl(fd, BLKGETSIZE, &size) >= 0) 122 return (blkid_loff_t)size << 9; 123#endif 124 125/* tested on FreeBSD 6.1-RELEASE i386 */ 126#ifdef DIOCGMEDIASIZE 127 if (ioctl(fd, DIOCGMEDIASIZE, &size64) >= 0) 128 return (off_t)size64; 129#endif /* DIOCGMEDIASIZE */ 130 131#ifdef FDGETPRM 132 if (ioctl(fd, FDGETPRM, &this_floppy) >= 0) 133 return (blkid_loff_t)this_floppy.size << 9; 134#endif 135#ifdef HAVE_SYS_DISKLABEL_H 136 /* 137 * This code works for FreeBSD 4.11 i386, except for the full device 138 * (such as /dev/ad0). It doesn't work properly for newer FreeBSD 139 * though. FreeBSD >= 5.0 should be covered by the DIOCGMEDIASIZE 140 * above however. 141 * 142 * Note that FreeBSD >= 4.0 has disk devices as unbuffered (raw, 143 * character) devices, so we need to check for S_ISCHR, too. 144 */ 145 if ((fstat(fd, &st) >= 0) && (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode))) 146 part = st.st_rdev & 7; 147 if (part >= 0 && (ioctl(fd, DIOCGDINFO, (char *)&lab) >= 0)) { 148 pp = &lab.d_partitions[part]; 149 if (pp->p_size) 150 return pp->p_size << 9; 151 } 152#endif /* HAVE_SYS_DISKLABEL_H */ 153 { 154#ifdef HAVE_FSTAT64 155 struct stat64 st; 156 if (fstat64(fd, &st) == 0) 157#else 158 struct stat st; 159 if (fstat(fd, &st) == 0) 160#endif 161 if (S_ISREG(st.st_mode)) 162 return st.st_size; 163 } 164 165 166 /* 167 * OK, we couldn't figure it out by using a specialized ioctl, 168 * which is generally the best way. So do binary search to 169 * find the size of the partition. 170 */ 171 low = 0; 172 for (high = 1024; valid_offset(fd, high); high *= 2) 173 low = high; 174 while (low < high - 1) 175 { 176 const blkid_loff_t mid = (low + high) / 2; 177 178 if (valid_offset(fd, mid)) 179 low = mid; 180 else 181 high = mid; 182 } 183 return low + 1; 184} 185 186#ifdef TEST_PROGRAM 187int main(int argc, char **argv) 188{ 189 blkid_loff_t bytes; 190 int fd; 191 192 if (argc < 2) { 193 fprintf(stderr, "Usage: %s device\n" 194 "Determine the size of a device\n", argv[0]); 195 return 1; 196 } 197 198 if ((fd = open(argv[1], O_RDONLY)) < 0) 199 perror(argv[0]); 200 201 bytes = blkid_get_dev_size(fd); 202 printf("Device %s has %Ld 1k blocks.\n", argv[1], 203 (unsigned long long) bytes >> 10); 204 205 return 0; 206} 207#endif 208