1 /* $NetBSD: dkcksum.c,v 1.1 2021/05/17 08:50:36 mrg Exp $ */
2
3 /*-
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * from: NetBSD: dkcksum.c,v 1.14 2013/05/03 16:05:12 matt Exp
32 */
33
34 #include <sys/cdefs.h>
35 #ifndef lint
36 #if 0
37 static char sccsid[] = "@(#)dkcksum.c 8.1 (Berkeley) 6/5/93";
38 #else
39 __RCSID("$NetBSD: dkcksum.c,v 1.1 2021/05/17 08:50:36 mrg Exp $");
40 #endif
41 #endif /* not lint */
42
43 #include <sys/types.h>
44 #include <sys/disklabel.h>
45 #include <lib/libkern/libkern.h>
46
47 uint16_t
dkcksum(const struct disklabel * lp)48 dkcksum(const struct disklabel *lp)
49 {
50
51 return dkcksum_sized(lp, lp->d_npartitions);
52 }
53
54 uint16_t
dkcksum_sized(const struct disklabel * lp,size_t npartitions)55 dkcksum_sized(const struct disklabel *lp, size_t npartitions)
56 {
57 const uint16_t *start, *end;
58 uint16_t sum;
59
60 sum = 0;
61 start = (const uint16_t *)lp;
62 end = (const uint16_t *)&lp->d_partitions[npartitions];
63 while (start < end) {
64 sum ^= *start++;
65 }
66 return sum;
67 }
68