mirror of https://github.com/vitalif/e2fsprogs
129 lines
2.4 KiB
C
129 lines
2.4 KiB
C
/*
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* getsize.c --- get the size of a partition.
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*
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* Copyright (C) 1995, 1995 Theodore Ts'o.
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Public
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* License.
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* %End-Header%
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*/
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#include <stdio.h>
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#if HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#if HAVE_STDLIB_H
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#include <stdlib.h>
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#endif
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#ifdef HAVE_ERRNO_H
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#include <errno.h>
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#endif
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#include <fcntl.h>
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#ifdef HAVE_LINUX_FS_H
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#include <linux/fs.h>
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#endif
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#ifdef HAVE_LINUX_FD_H
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#include <sys/ioctl.h>
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#include <linux/fd.h>
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#endif
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#ifdef HAVE_SYS_DISKLABEL_H
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#include <sys/ioctl.h>
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#include <sys/disklabel.h>
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#endif /* HAVE_SYS_DISKLABEL_H */
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#include <linux/ext2_fs.h>
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#include "ext2fs.h"
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static int valid_offset (int fd, ext2_loff_t offset)
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{
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char ch;
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if (ext2fs_llseek (fd, offset, 0) < 0)
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return 0;
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if (read (fd, &ch, 1) < 1)
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return 0;
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return 1;
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}
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/*
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* Returns the number of blocks in a partition
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*/
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errcode_t ext2fs_get_device_size(const char *file, int blocksize,
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blk_t *retblocks)
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{
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int fd;
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long size;
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ext2_loff_t high, low;
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#ifdef FDGETPRM
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struct floppy_struct this_floppy;
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#endif
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#ifdef HAVE_SYS_DISKLABEL_H
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int part;
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struct disklabel lab;
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struct partition *pp;
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char ch;
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#endif /* HAVE_SYS_DISKLABEL_H */
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fd = open(file, O_RDONLY);
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if (fd < 0)
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return errno;
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#ifdef BLKGETSIZE
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if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
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close(fd);
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*retblocks = size / (blocksize / 512);
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return 0;
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}
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#endif
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#ifdef FDGETPRM
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if (ioctl(fd, FDGETPRM, &this_floppy) >= 0) {
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close(fd);
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*retblocks = this_floppy.size / (blocksize / 512);
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return 0;
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}
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#endif
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#ifdef HAVE_SYS_DISKLABEL_H
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part = strlen(file) - 1;
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if (part >= 0) {
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ch = file[part];
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if (isdigit(ch))
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part = 0;
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else if (ch >= 'a' && ch <= 'h')
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part = ch - 'a';
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else
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part = -1;
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}
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if (part >= 0 && (ioctl(fd, DIOCGDINFO, (char *)&lab) >= 0)) {
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pp = &lab.d_partitions[part];
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if (pp->p_size) {
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close(fd);
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*retblocks = pp->p_size / (blocksize / 512);
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return 0;
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}
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}
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#endif /* HAVE_SYS_DISKLABEL_H */
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/*
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* OK, we couldn't figure it out by using a specialized ioctl,
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* which is generally the best way. So do binary search to
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* find the size of the partition.
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*/
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low = 0;
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for (high = 1024; valid_offset (fd, high); high *= 2)
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low = high;
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while (low < high - 1)
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{
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const ext2_loff_t mid = (low + high) / 2;
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if (valid_offset (fd, mid))
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low = mid;
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else
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high = mid;
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}
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valid_offset (fd, 0);
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close(fd);
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*retblocks = (low + 1) / blocksize;
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return 0;
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}
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