1 /*- 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from: @(#)disklabel.c 8.1 (Berkeley) 6/11/93 34 * $Id: disklabel.c,v 1.2 1994/08/22 21:56:02 brezak Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/disklabel.h> 39 40 int dkcksum __P((struct disklabel *)); 41 42 char * 43 getdisklabel(buf, lp) 44 const char *buf; 45 struct disklabel *lp; 46 { 47 struct disklabel *dlp, *elp; 48 char *msg = (char *)0; 49 50 elp = (struct disklabel *)(buf + DEV_BSIZE - sizeof(*dlp)); 51 for (dlp = (struct disklabel *)buf; dlp <= elp; 52 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 53 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { 54 if (msg == (char *)0) 55 msg = "no disk label"; 56 } else if (dlp->d_npartitions > MAXPARTITIONS || 57 dkcksum(dlp) != 0) 58 msg = "disk label corrupted"; 59 else { 60 *lp = *dlp; 61 msg = (char *)0; 62 break; 63 } 64 } 65 return (msg); 66 } 67 68 /* 69 * Compute checksum for disk label. 70 */ 71 int 72 dkcksum(lp) 73 register struct disklabel *lp; 74 { 75 register u_short *start, *end; 76 register u_short sum = 0; 77 78 start = (u_short *)lp; 79 end = (u_short *)&lp->d_partitions[lp->d_npartitions]; 80 while (start < end) 81 sum ^= *start++; 82 return (sum); 83 } 84