1 /* $NetBSD: disklabel.c,v 1.3 1994/10/26 05:44:42 cgd Exp $ */ 2 3 /*- 4 * Copyright (c) 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)disklabel.c 8.1 (Berkeley) 6/11/93 36 */ 37 38 #include <sys/param.h> 39 #include <sys/disklabel.h> 40 41 int dkcksum __P((struct disklabel *)); 42 43 char * 44 getdisklabel(buf, lp) 45 const char *buf; 46 struct disklabel *lp; 47 { 48 struct disklabel *dlp, *elp; 49 char *msg = (char *)0; 50 51 elp = (struct disklabel *)(buf + DEV_BSIZE - sizeof(*dlp)); 52 for (dlp = (struct disklabel *)buf; dlp <= elp; 53 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 54 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { 55 if (msg == (char *)0) 56 msg = "no disk label"; 57 } else if (dlp->d_npartitions > MAXPARTITIONS || 58 dkcksum(dlp) != 0) 59 msg = "disk label corrupted"; 60 else { 61 *lp = *dlp; 62 msg = (char *)0; 63 break; 64 } 65 } 66 return (msg); 67 } 68 69 /* 70 * Compute checksum for disk label. 71 */ 72 int 73 dkcksum(lp) 74 register struct disklabel *lp; 75 { 76 register u_short *start, *end; 77 register u_short sum = 0; 78 79 start = (u_short *)lp; 80 end = (u_short *)&lp->d_partitions[lp->d_npartitions]; 81 while (start < end) 82 sum ^= *start++; 83 return (sum); 84 } 85