release/src/router/busybox/e2fsprogs/blkid/blkid_getsize.c

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