1 /* vi: set sw=4 ts=4: */
3 * getsize.c --- get the size of a partition.
5 * Copyright (C) 1995, 1995 Theodore Ts'o.
8 * This file may be redistributed under the terms of the
9 * GNU Lesser General Public License.
13 /* include this before sys/queues.h! */
22 #ifdef HAVE_SYS_IOCTL_H
23 #include <sys/ioctl.h>
25 #ifdef HAVE_LINUX_FD_H
28 #ifdef HAVE_SYS_DISKLABEL_H
29 #include <sys/disklabel.h>
32 #ifdef HAVE_SYS_DISK_H
33 #ifdef HAVE_SYS_QUEUE_H
34 #include <sys/queue.h> /* for LIST_HEAD */
39 #include <sys/utsname.h>
42 #if defined(__linux__) && defined(_IO) && !defined(BLKGETSIZE)
43 #define BLKGETSIZE _IO(0x12,96) /* return device size */
46 #if defined(__linux__) && defined(_IOR) && !defined(BLKGETSIZE64)
47 #define BLKGETSIZE64 _IOR(0x12,114,size_t) /* return device size in bytes (u64 *arg) */
51 #define BLKGETSIZE DKIOCGETBLOCKCOUNT32
52 #endif /* APPLE_DARWIN */
54 static int valid_offset(int fd, blkid_loff_t offset)
58 if (blkid_llseek(fd, offset, 0) < 0)
60 if (read(fd, &ch, 1) < 1)
66 * Returns the number of blocks in a partition
68 blkid_loff_t blkid_get_dev_size(int fd)
70 int valid_blkgetsize64 = 1;
74 unsigned long long size64;
76 blkid_loff_t high, low;
78 struct floppy_struct this_floppy;
80 #ifdef HAVE_SYS_DISKLABEL_H
86 #endif /* HAVE_SYS_DISKLABEL_H */
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))
93 return (blkid_loff_t) size64 << 9;
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;
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 */
114 if (ioctl(fd, BLKGETSIZE, &size) >= 0)
115 return (blkid_loff_t)size << 9;
119 if (ioctl(fd, FDGETPRM, &this_floppy) >= 0)
120 return (blkid_loff_t)this_floppy.size << 9;
122 #ifdef HAVE_SYS_DISKLABEL_H
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.
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];
134 return pp->p_size << 9;
137 #endif /* HAVE_SYS_DISKLABEL_H */
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.
145 for (high = 1024; valid_offset(fd, high); high *= 2)
147 while (low < high - 1)
149 const blkid_loff_t mid = (low + high) / 2;
151 if (valid_offset(fd, mid))
160 int main(int argc, char **argv)
166 fprintf(stderr, "Usage: %s device\n"
167 "Determine the size of a device\n", argv[0]);
171 if ((fd = open(argv[1], O_RDONLY)) < 0)
174 bytes = blkid_get_dev_size(fd);
175 printf("Device %s has %lld 1k blocks.\n", argv[1], bytes >> 10);