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
valid_offset(int fd,blkid_loff_t offset)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 */
blkid_get_dev_size(int fd)76 blkid_loff_t blkid_get_dev_size(int fd)
77 {
78 unsigned long long size64;
79 blkid_loff_t high, low;
80
81 #ifdef DKIOCGETBLOCKCOUNT /* For Apple Darwin */
82 if (ioctl(fd, DKIOCGETBLOCKCOUNT, &size64) >= 0) {
83 if (sizeof(blkid_loff_t) < sizeof(unsigned long long) &&
84 (size64 << 9) > 0xFFFFFFFF)
85 return 0; /* EFBIG */
86 return (blkid_loff_t)size64 << 9;
87 }
88 #endif
89
90 #ifdef BLKGETSIZE64
91 {
92 int valid_blkgetsize64 = 1;
93 #ifdef __linux__
94 struct utsname ut;
95
96 if ((uname(&ut) == 0) &&
97 ((ut.release[0] == '2') && (ut.release[1] == '.') &&
98 (ut.release[2] < '6') && (ut.release[3] == '.')))
99 valid_blkgetsize64 = 0;
100 #endif
101 if (valid_blkgetsize64 &&
102 ioctl(fd, BLKGETSIZE64, &size64) >= 0) {
103 if (sizeof(blkid_loff_t) < sizeof(unsigned long long) &&
104 (size64 > 0xFFFFFFFF))
105 return 0; /* EFBIG */
106 return size64;
107 }
108 }
109 #endif /* BLKGETSIZE64 */
110
111 #ifdef BLKGETSIZE
112 {
113 unsigned long size;
114
115 if (ioctl(fd, BLKGETSIZE, &size) >= 0)
116 return (blkid_loff_t)size << 9;
117 }
118 #endif
119
120 /* tested on FreeBSD 6.1-RELEASE i386 */
121 #ifdef DIOCGMEDIASIZE
122 if (ioctl(fd, DIOCGMEDIASIZE, &size64) >= 0)
123 return (off_t)size64;
124 #endif /* DIOCGMEDIASIZE */
125
126 #ifdef FDGETPRM
127 {
128 struct floppy_struct this_floppy;
129
130 if (ioctl(fd, FDGETPRM, &this_floppy) >= 0)
131 return (blkid_loff_t)this_floppy.size << 9;
132 }
133 #endif
134 #if defined(HAVE_SYS_DISKLABEL_H) && defined(DIOCGDINFO)
135 {
136 int part = -1;
137 struct disklabel lab;
138 struct partition *pp;
139 char ch;
140 struct stat st;
141
142 /*
143 * This code works for FreeBSD 4.11 i386, except for the full
144 * device (such as /dev/ad0). It doesn't work properly for
145 * newer FreeBSD though. FreeBSD >= 5.0 should be covered by
146 * the DIOCGMEDIASIZE above however.
147 *
148 * Note that FreeBSD >= 4.0 has disk devices as unbuffered (raw,
149 * character) devices, so we need to check for S_ISCHR, too.
150 */
151 if (fstat(fd, &st) >= 0 &&
152 (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode)))
153 part = st.st_rdev & 7;
154
155 if (part >= 0 && (ioctl(fd, DIOCGDINFO, (char *)&lab) >= 0)) {
156 pp = &lab.d_partitions[part];
157 if (pp->p_size)
158 return pp->p_size << 9;
159 }
160 }
161 #endif /* defined(HAVE_SYS_DISKLABEL_H) && defined(DIOCGDINFO) */
162 {
163 #if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
164 struct stat64 st;
165 if (fstat64(fd, &st) == 0)
166 #else
167 struct stat st;
168 if (fstat(fd, &st) == 0)
169 #endif
170 if (S_ISREG(st.st_mode))
171 return st.st_size;
172 }
173
174 /*
175 * OK, we couldn't figure it out by using a specialized ioctl,
176 * which is generally the best way. So do binary search to
177 * find the size of the partition.
178 */
179 low = 0;
180 for (high = 1024; valid_offset(fd, high); high *= 2)
181 low = high;
182 while (low < high - 1) {
183 const blkid_loff_t mid = (low + high) / 2;
184
185 if (valid_offset(fd, mid))
186 low = mid;
187 else
188 high = mid;
189 }
190 return low + 1;
191 }
192
193 #ifdef TEST_PROGRAM
main(int argc,char ** argv)194 int main(int argc, char **argv)
195 {
196 long long bytes;
197 int fd;
198
199 if (argc < 2) {
200 fprintf(stderr, "Usage: %s device\n"
201 "Determine the size of a device\n", argv[0]);
202 return 1;
203 }
204
205 if ((fd = open(argv[1], O_RDONLY)) < 0)
206 perror(argv[0]);
207
208 bytes = blkid_get_dev_size(fd);
209 printf("Device %s has %lld 1k blocks.\n", argv[1],
210 (unsigned long long)bytes >> 10);
211
212 return 0;
213 }
214 #endif
215