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/*
* getsize.c --- get the size of a partition.
*
* Copyright (C) 1995 Theodore Ts'o. This file may be
* redistributed under the terms of the GNU Public License.
*/
#include <stdio.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <fcntl.h>
#ifdef HAVE_LINUX_FS_H
#include <linux/fs.h>
#endif
#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 */
#include <linux/ext2_fs.h>
#include "ext2fs.h"
static int valid_offset (int fd, ext2_loff_t offset)
{
char ch;
if (ext2_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;
int size;
ext2_loff_t high, low;
#ifdef FDGETPRM
struct floppy_struct this_floppy;
#endif
#ifdef HAVE_SYS_DISKLABEL_H
struct disklabel lab;
struct partition *pp;
char ch;
#endif /* HAVE_SYS_DISKLABEL_H */
fd = open(file, O_RDWR);
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
size = strlen(file) - 1;
if (size >= 0) {
ch = file[size];
if (isdigit(ch))
size = 0;
else if (ch >= 'a' && ch <= 'h')
size = ch - 'a';
else
size = -1;
}
if (size >= 0 && (ioctl(fd, DIOCGDINFO, (char *)&lab) >= 0)) {
pp = &lab.d_partitions[size];
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 besy 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;
}
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