mirror of https://github.com/vitalif/e2fsprogs
135 lines
2.6 KiB
C
135 lines
2.6 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
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* GNU Lesser General Public License.
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* %End-Header%
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*/
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#define _LARGEFILE_SOURCE
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#define _LARGEFILE64_SOURCE
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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_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_FD_H
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#include <sys/ioctl.h>
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#include <linux/fd.h>
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#endif /* HAVE_LINUX_FD_H */
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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 "blkid/blkid.h"
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#if defined(__linux__) && defined(_IO) && !defined(BLKGETSIZE)
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#define BLKGETSIZE _IO(0x12,96) /* return device size */
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#endif
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static int valid_offset(int fd, blkid_loff_t offset)
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{
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char ch;
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if (blkid_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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blkid_loff_t blkid_get_dev_size(int fd)
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{
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#ifdef BLKGETSIZE
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unsigned long size;
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#endif
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blkid_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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#ifdef BLKGETSIZE
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if (ioctl(fd, BLKGETSIZE, &size) >= 0)
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return (blkid_loff_t)size << 9;
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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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return (blkid_loff_t)this_floppy.size << 9;
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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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return pp->p_size << 9;
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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 blkid_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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return low + 1;
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}
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#ifdef TEST_PROGRAM
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int main(int argc, char **argv)
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{
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blkid_loff_t bytes;
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int fd;
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if (argc < 2) {
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fprintf(stderr, "Usage: %s device\n"
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"Determine the size of a device\n", argv[0]);
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return 1;
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}
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if ((fd = open(argv[1], O_RDONLY)) < 0)
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perror(argv[0]);
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bytes = blkid_get_dev_size(fd);
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printf("Device %s has %Ld 1k blocks.\n", argv[1], bytes >> 10);
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return 0;
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}
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#endif
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