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1/* $OpenBSD: disklabel.c,v 1.7 2025/11/20 14:57:39 krw Exp $ */
2/* $NetBSD: disklabel.c,v 1.3 1994/10/26 05:44:42 cgd Exp $ */
3
4/*-
5 * Copyright (c) 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * @(#)disklabel.c 8.1 (Berkeley) 6/11/93
33 */
34
35#include <sys/param.h>
36#include <sys/disklabel.h>
37#include "stand.h"
38
39#define offsetof(s, e) ((size_t)&((s *)0)->e)
40
41char *
42getdisklabel(const char *buf, struct disklabel *lp)
43{
44 struct disklabel *dlp, *elp;
45 char *msg = NULL;
46 size_t lpsz;
47
48 /*
49 * XXX Only read the old smaller "skinny" label for now which
50 * has 16 partitions. offsetof() is used to carve struct disklabel.
51 * Later we'll add code to read and process the "fat" label with
52 * 52 partitions.
53 */
54 lpsz = offsetof(struct disklabel, d_partitions[MAXPARTITIONS16]);
55
56 elp = (struct disklabel *)(buf + DEV_BSIZE - lpsz);
57 for (dlp = (struct disklabel *)buf; dlp <= elp;
58 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
59 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
60 if (msg == NULL)
61 msg = "no disk label";
62 } else if (dlp->d_npartitions > MAXPARTITIONS16 ||
63 dkcksum(dlp) != 0)
64 msg = "disk label corrupted";
65 else {
66 memcpy(lp, dlp, lpsz);
67 msg = NULL;
68 break;
69 }
70 }
71 return (msg);
72}