freebsd-skq/lib/libufs/block.c
jmallett 70c14dc49d Don't crash when utilities are dumb and try to read less than the disk block
size (dumpfs may try to read the cylinder size (or is is sector size?) by way
of bread).  Prevents a bounds error.
2003-01-19 01:39:53 +00:00

88 lines
2.5 KiB
C

/*
* Copyright (c) 2002 Juli Mallett. All rights reserved.
*
* This software was written by Juli Mallett <jmallett@FreeBSD.org> for the
* FreeBSD project. Redistribution and use in source and binary forms, with
* or without modification, are permitted provided that the following
* conditions are met:
*
* 1. Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistribution in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/disklabel.h>
#include <sys/stat.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <libufs.h>
ssize_t
bread(struct uufsd *disk, ufs2_daddr_t blockno, void *data, size_t size)
{
char *buf;
ssize_t cnt;
ERROR(disk, NULL);
/*
* For when we need to work with the data as a buffer.
*/
buf = data;
cnt = pread(disk->d_fd, data, size, (off_t)(blockno * disk->d_bsize));
/*
* In case of failure, zero data, which must be fs_bsize.
*/
if (cnt != size) {
ERROR(disk, "short read from block device");
for (cnt = 0; cnt < MIN(size, disk->d_fs.fs_bsize); cnt++)
buf[cnt] = 0;
return -1;
}
return cnt;
}
ssize_t
bwrite(struct uufsd *disk, ufs2_daddr_t blockno, const void *data, size_t size)
{
ssize_t cnt;
ERROR(disk, NULL);
cnt = pwrite(disk->d_fd, data, size, (off_t)(blockno * disk->d_bsize));
if (cnt != size) {
ERROR(disk, "short write to block device");
return -1;
}
return cnt;
}