/* * Copyright (c) 1992 University of Utah. * Copyright (c) 1982, 1986, 1988, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: Utah $Hdr: label.c 1.1 92/12/05$ * * @(#)label.c 8.1 (Berkeley) 6/10/93 */ /* * Derived from routines in ufs/ufs/ufs_disksubr.c. */ #include <sys/param.h> #include <sys/disklabel.h> #include <stand.att/saio.h> /* * Attempt to read a disk label from a device using the indicated stategy * routine. Returns NULL on success and an error string on failure. */ char * readdisklabel(io, strat, lp) struct iob *io; int (*strat)(); register struct disklabel *lp; { struct iob liob; struct disklabel *dlp; char *msg = NULL; liob.i_adapt = io->i_adapt; liob.i_ctlr = io->i_ctlr; liob.i_unit = io->i_unit; liob.i_part = 2; liob.i_boff = 0; liob.i_cyloff = 0; liob.i_bn = LABELSECTOR; liob.i_ma = liob.i_buf; liob.i_cc = lp->d_secsize ? lp->d_secsize : DEV_BSIZE; if ((*strat)(&liob, F_READ) == -1) return ("I/O error"); for (dlp = (struct disklabel *)liob.i_buf; dlp <= (struct disklabel *)(liob.i_buf+DEV_BSIZE-sizeof(*dlp)); dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { if (msg == NULL) msg = "no disk label"; } else if (dlp->d_npartitions > MAXPARTITIONS || dkcksum(dlp)) msg = "disk label corrupted"; else { *lp = *dlp; msg = NULL; break; } } return (msg); } /* * Compute checksum for disk label. */ dkcksum(lp) register struct disklabel *lp; { register u_short *start, *end; register u_short sum = 0; start = (u_short *)lp; end = (u_short *)&lp->d_partitions[lp->d_npartitions]; while (start < end) sum ^= *start++; return (sum); }