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/*
* getsize.c --- get the size of a partition.
*
* Copyright (C) 1995, 1995 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#define _LARGEFILE_SOURCE
#define _LARGEFILE64_SOURCE
#include <stdio.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#include <fcntl.h>
#ifdef HAVE_LINUX_FD_H
#include <sys/ioctl.h>
#include <linux/fd.h>
#endif
#ifdef HAVE_SYS_DISKLABEL_H
#include <sys/ioctl.h>
#include <sys/disklabel.h>
#endif /* HAVE_SYS_DISKLABEL_H */
#if defined(__linux__) && defined(_IO) && !defined(BLKGETSIZE)
#define BLKGETSIZE _IO(0x12,96) /* return device size */
#endif
#include "ext2_fs.h"
#include "ext2fs.h"
static int valid_offset (int fd, ext2_loff_t offset)
{
char ch;
if (ext2fs_llseek (fd, offset, 0) < 0)
return 0;
if (read (fd, &ch, 1) < 1)
return 0;
return 1;
}
/*
* Returns the number of blocks in a partition
*/
errcode_t ext2fs_get_device_size(const char *file, int blocksize,
blk_t *retblocks)
{
int fd;
#ifdef BLKGETSIZE
unsigned long size;
#endif
ext2_loff_t high, low;
#ifdef FDGETPRM
struct floppy_struct this_floppy;
#endif
#ifdef HAVE_SYS_DISKLABEL_H
int part;
struct disklabel lab;
struct partition *pp;
char ch;
#endif /* HAVE_SYS_DISKLABEL_H */
#ifdef HAVE_OPEN64
fd = open64(file, O_RDONLY);
#else
fd = open(file, O_RDONLY);
#endif
if (fd < 0)
return errno;
#ifdef BLKGETSIZE
if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
close(fd);
*retblocks = size / (blocksize / 512);
return 0;
}
#endif
#ifdef FDGETPRM
if (ioctl(fd, FDGETPRM, &this_floppy) >= 0) {
close(fd);
*retblocks = this_floppy.size / (blocksize / 512);
return 0;
}
#endif
#ifdef HAVE_SYS_DISKLABEL_H
part = strlen(file) - 1;
if (part >= 0) {
ch = file[part];
if (isdigit(ch))
part = 0;
else if (ch >= 'a' && ch <= 'h')
part = ch - 'a';
else
part = -1;
}
if (part >= 0 && (ioctl(fd, DIOCGDINFO, (char *)&lab) >= 0)) {
pp = &lab.d_partitions[part];
if (pp->p_size) {
close(fd);
*retblocks = pp->p_size / (blocksize / 512);
return 0;
}
}
#endif /* HAVE_SYS_DISKLABEL_H */
/*
* OK, we couldn't figure it out by using a specialized ioctl,
* which is generally the best way. So do binary search to
* find the size of the partition.
*/
low = 0;
for (high = 1024; valid_offset (fd, high); high *= 2)
low = high;
while (low < high - 1)
{
const ext2_loff_t mid = (low + high) / 2;
if (valid_offset (fd, mid))
low = mid;
else
high = mid;
}
valid_offset (fd, 0);
close(fd);
*retblocks = (low + 1) / blocksize;
return 0;
}
#ifdef DEBUG
int main(int argc, char **argv)
{
blk_t blocks;
int retval;
if (argc < 2) {
fprintf(stderr, "Usage: %s device\n", argv[0]);
exit(1);
}
retval = ext2fs_get_device_size(argv[1], 1024, &blocks);
if (retval) {
com_err(argv[0], retval,
"while calling ext2fs_get_device_size");
exit(1);
}
printf("Device %s has %d 1k blocks.\n", argv[1], blocks);
exit(0);
}
#endif
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