block.c revision 116084 
1/*
2 * Copyright (c) 2002 Juli Mallett.  All rights reserved.
3 *
4 * This software was written by Juli Mallett <jmallett@FreeBSD.org> for the
5 * FreeBSD project.  Redistribution and use in source and binary forms, with
6 * or without modification, are permitted provided that the following
7 * conditions are met:
8 *
9 * 1. Redistribution of source code must retain the above copyright notice,
10 *    this list of conditions and the following disclaimer.
11 * 2. Redistribution in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
19 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
20 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
23 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
24 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 * POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/lib/libufs/block.c 116084 2003-06-09 09:32:29Z jmallett $");
30
31#include <sys/param.h>
32#include <sys/mount.h>
33#include <sys/disklabel.h>
34#include <sys/stat.h>
35
36#include <ufs/ufs/ufsmount.h>
37#include <ufs/ufs/dinode.h>
38#include <ufs/ffs/fs.h>
39
40#include <errno.h>
41#include <fcntl.h>
42#include <stdio.h>
43#include <string.h>
44#include <unistd.h>
45
46#include <libufs.h>
47
48ssize_t
49bread(struct uufsd *disk, ufs2_daddr_t blockno, void *data, size_t size)
50{
51	char *buf;
52	ssize_t cnt;
53
54	ERROR(disk, NULL);
55
56	/*
57	 * For when we need to work with the data as a buffer.
58	 */
59	buf = data;
60
61	cnt = pread(disk->d_fd, data, size, (off_t)(blockno * disk->d_bsize));
62	if (cnt == -1) {
63		ERROR(disk, "read error from block device");
64		goto fail;
65	}
66	if (cnt == 0) {
67		ERROR(disk, "end of file from block device");
68		goto fail;
69	}
70	if ((size_t)cnt != size) {
71		ERROR(disk, "short read or read error from block device");
72		goto fail;
73	}
74	return (cnt);
75fail:	memset(buf, 0, size);
76	return (-1);
77}
78
79ssize_t
80bwrite(struct uufsd *disk, ufs2_daddr_t blockno, const void *data, size_t size)
81{
82	ssize_t cnt;
83	int rv;
84
85	ERROR(disk, NULL);
86
87	rv = ufs_disk_write(disk);
88	if (rv == -1) {
89		ERROR(disk, "failed to open disk for writing");
90		return (-1);
91	}
92
93	cnt = pwrite(disk->d_fd, data, size, (off_t)(blockno * disk->d_bsize));
94	if (cnt == -1) {
95		ERROR(disk, "write error to block device");
96		return (-1);
97	}
98	if ((size_t)cnt != size) {
99		ERROR(disk, "short write to block device");
100		return (-1);
101	}
102
103	return (cnt);
104}
105