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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 
valid_offset(int fd,blkid_loff_t offset)61 static 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  */
blkid_get_dev_size(int fd)75 blkid_loff_t blkid_get_dev_size(int fd)
76 {
77 	unsigned long long size64;
78 	blkid_loff_t high, low;
79 
80 #ifdef DKIOCGETBLOCKCOUNT	/* For Apple Darwin */
81 	if (ioctl(fd, DKIOCGETBLOCKCOUNT, &size64) >= 0) {
82 		if (sizeof(blkid_loff_t) < sizeof(unsigned long long) &&
83 		    (size64 << 9) > 0xFFFFFFFF)
84 			return 0; /* EFBIG */
85 		return (blkid_loff_t)size64 << 9;
86 	}
87 #endif
88 
89 #ifdef BLKGETSIZE64
90 	{
91 		int valid_blkgetsize64 = 1;
92 #ifdef __linux__
93 		struct		utsname ut;
94 
95 		if ((uname(&ut) == 0) &&
96 		    ((ut.release[0] == '2') && (ut.release[1] == '.') &&
97 		     (ut.release[2] < '6') && (ut.release[3] == '.')))
98 			valid_blkgetsize64 = 0;
99 #endif
100 		if (valid_blkgetsize64 &&
101 		    ioctl(fd, BLKGETSIZE64, &size64) >= 0) {
102 			if (sizeof(blkid_loff_t) < sizeof(unsigned long long) &&
103 			    (size64 > 0xFFFFFFFF))
104 				return 0; /* EFBIG */
105 			return size64;
106 		}
107 	}
108 #endif /* BLKGETSIZE64 */
109 
110 #ifdef BLKGETSIZE
111 	{
112 		unsigned long size;
113 
114 		if (ioctl(fd, BLKGETSIZE, &size) >= 0)
115 			return (blkid_loff_t)size << 9;
116 	}
117 #endif
118 
119 /* tested on FreeBSD 6.1-RELEASE i386 */
120 #ifdef DIOCGMEDIASIZE
121 	if (ioctl(fd, DIOCGMEDIASIZE, &size64) >= 0)
122 		return (off_t)size64;
123 #endif /* DIOCGMEDIASIZE */
124 
125 #ifdef FDGETPRM
126 	{
127 		struct floppy_struct this_floppy;
128 
129 		if (ioctl(fd, FDGETPRM, &this_floppy) >= 0)
130 			return (blkid_loff_t)this_floppy.size << 9;
131 	}
132 #endif
133 #ifdef HAVE_SYS_DISKLABEL_H
134 	{
135 		int part = -1;
136 		struct disklabel lab;
137 		struct partition *pp;
138 		char ch;
139 		struct stat st;
140 
141 		/*
142 		 * This code works for FreeBSD 4.11 i386, except for the full
143 		 * device (such as /dev/ad0). It doesn't work properly for
144 		 * newer FreeBSD though. FreeBSD >= 5.0 should be covered by
145 		 * the DIOCGMEDIASIZE above however.
146 		 *
147 		 * Note that FreeBSD >= 4.0 has disk devices as unbuffered (raw,
148 		 * character) devices, so we need to check for S_ISCHR, too.
149 		 */
150 		if (fstat(fd, &st) >= 0 &&
151 		    (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode)))
152 			part = st.st_rdev & 7;
153 
154 		if (part >= 0 && (ioctl(fd, DIOCGDINFO, (char *)&lab) >= 0)) {
155 			pp = &lab.d_partitions[part];
156 			if (pp->p_size)
157 				return pp->p_size << 9;
158 		}
159 	}
160 #endif /* HAVE_SYS_DISKLABEL_H */
161 	{
162 #if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
163 		struct stat64   st;
164 		if (fstat64(fd, &st) == 0)
165 #else
166 		struct stat	st;
167 		if (fstat(fd, &st) == 0)
168 #endif
169 			if (S_ISREG(st.st_mode))
170 				return st.st_size;
171 	}
172 
173 	/*
174 	 * OK, we couldn't figure it out by using a specialized ioctl,
175 	 * which is generally the best way.  So do binary search to
176 	 * find the size of the partition.
177 	 */
178 	low = 0;
179 	for (high = 1024; valid_offset(fd, high); high *= 2)
180 		low = high;
181 	while (low < high - 1) {
182 		const blkid_loff_t mid = (low + high) / 2;
183 
184 		if (valid_offset(fd, mid))
185 			low = mid;
186 		else
187 			high = mid;
188 	}
189 	return low + 1;
190 }
191 
192 #ifdef TEST_PROGRAM
main(int argc,char ** argv)193 int main(int argc, char **argv)
194 {
195 	long long bytes;
196 	int	fd;
197 
198 	if (argc < 2) {
199 		fprintf(stderr, "Usage: %s device\n"
200 			"Determine the size of a device\n", argv[0]);
201 		return 1;
202 	}
203 
204 	if ((fd = open(argv[1], O_RDONLY)) < 0)
205 		perror(argv[0]);
206 
207 	bytes = blkid_get_dev_size(fd);
208 	printf("Device %s has %lld 1k blocks.\n", argv[1],
209 	       (unsigned long long)bytes >> 10);
210 
211 	return 0;
212 }
213 #endif
214