180 lines
3.9 KiB
C
180 lines
3.9 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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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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/* include this before sys/queues.h! */
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#include "blkidP.h"
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#include <stdio.h>
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#include <unistd.h>
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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_SYS_IOCTL_H
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#include <sys/ioctl.h>
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#endif
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#ifdef HAVE_LINUX_FD_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/disklabel.h>
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#include <sys/stat.h>
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#endif
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#ifdef HAVE_SYS_DISK_H
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#ifdef HAVE_SYS_QUEUE_H
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#include <sys/queue.h> /* for LIST_HEAD */
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#endif
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#include <sys/disk.h>
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#endif
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#ifdef __linux__
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#include <sys/utsname.h>
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#endif
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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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#if defined(__linux__) && defined(_IOR) && !defined(BLKGETSIZE64)
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#define BLKGETSIZE64 _IOR(0x12,114,size_t) /* return device size in bytes (u64 *arg) */
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#endif
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#ifdef APPLE_DARWIN
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#define BLKGETSIZE DKIOCGETBLOCKCOUNT32
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#endif /* APPLE_DARWIN */
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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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int valid_blkgetsize64 = 1;
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#ifdef __linux__
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struct utsname ut;
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#endif
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unsigned long long size64;
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unsigned long size;
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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 = -1;
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struct disklabel lab;
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struct partition *pp;
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char ch;
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struct stat st;
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#endif /* HAVE_SYS_DISKLABEL_H */
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#ifdef DKIOCGETBLOCKCOUNT /* For Apple Darwin */
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if (ioctl(fd, DKIOCGETBLOCKCOUNT, &size64) >= 0) {
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if ((sizeof(blkid_loff_t) < sizeof(unsigned long long))
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&& (size64 << 9 > 0xFFFFFFFF))
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return 0; /* EFBIG */
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return (blkid_loff_t) size64 << 9;
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}
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#endif
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#ifdef BLKGETSIZE64
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#ifdef __linux__
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if ((uname(&ut) == 0) &&
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((ut.release[0] == '2') && (ut.release[1] == '.') &&
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(ut.release[2] < '6') && (ut.release[3] == '.')))
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valid_blkgetsize64 = 0;
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#endif
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if (valid_blkgetsize64 &&
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ioctl(fd, BLKGETSIZE64, &size64) >= 0) {
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if ((sizeof(blkid_loff_t) < sizeof(unsigned long long))
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&& ((size64) > 0xFFFFFFFF))
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return 0; /* EFBIG */
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return size64;
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}
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#endif
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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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#if 0
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/*
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* This should work in theory but I haven't tested it. Anyone
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* on a BSD system want to test this for me? In the meantime,
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* binary search mechanism should work just fine.
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*/
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if ((fstat(fd, &st) >= 0) && S_ISBLK(st.st_mode))
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part = st.st_rdev & 7;
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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
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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 %lld 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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