/*
 * Copyright (c) 1982, 1986, 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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: @(#)ufs_disksubr.c	8.5 (Berkeley) 1/21/94
 *	$Id: disksubr.c,v 1.4 1994/05/13 14:00:21 mycroft Exp $
 */

#include "param.h"
#include "systm.h"
#include "buf.h"
#include "disklabel.h"
#include "syslog.h"

#define	b_cylinder	b_resid

/*
 * Attempt to read a disk label from a device using the indicated stategy
 * routine.  The label must be partly set up before this: secpercyl and
 * anything required in the strategy routine (e.g., sector size) must be
 * filled in before calling us.  Returns null on success and an error
 * string on failure.
 */
char *
readdisklabel(dev, strat, lp, osdep)
	dev_t dev;
	void (*strat)();
	register struct disklabel *lp;
	struct cpu_disklabel *osdep;
{
	register struct buf *bp;
	struct disklabel *dlp;
	char *msg = NULL;

	if (lp->d_secperunit == 0)
		lp->d_secperunit = 0x1fffffff;
	lp->d_npartitions = 1;
	if (lp->d_partitions[0].p_size == 0)
		lp->d_partitions[0].p_size = 0x1fffffff;
	lp->d_partitions[0].p_offset = 0;

	bp = geteblk((int)lp->d_secsize);
	bp->b_dev = dev;
	bp->b_blkno = LABELSECTOR;
	bp->b_bcount = lp->d_secsize;
	bp->b_flags = B_BUSY | B_READ;
	bp->b_cylinder = LABELSECTOR / lp->d_secpercyl;
	(*strat)(bp);
	if (biowait(bp))
		msg = "I/O error";
	else for (dlp = (struct disklabel *)bp->b_data;
	    dlp <= (struct disklabel *)((char *)bp->b_data +
	    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) != 0)
			msg = "disk label corrupted";
		else {
			*lp = *dlp;
			msg = NULL;
			break;
		}
	}
	bp->b_flags = B_INVAL | B_AGE;
	brelse(bp);
	return (msg);
}

/*
 * Check new disk label for sensibility before setting it.
 */
int
setdisklabel(olp, nlp, openmask, osdep)
	register struct disklabel *olp, *nlp;
	u_long openmask;
	struct cpu_disklabel *osdep;
{
	register i;
	register struct partition *opp, *npp;

	if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC ||
	    dkcksum(nlp) != 0)
		return (EINVAL);
	while ((i = ffs((long)openmask)) != 0) {
		i--;
		openmask &= ~(1 << i);
		if (nlp->d_npartitions <= i)
			return (EBUSY);
		opp = &olp->d_partitions[i];
		npp = &nlp->d_partitions[i];
		if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size)
			return (EBUSY);
		/*
		 * Copy internally-set partition information
		 * if new label doesn't include it.		XXX
		 */
		if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) {
			npp->p_fstype = opp->p_fstype;
			npp->p_fsize = opp->p_fsize;
			npp->p_frag = opp->p_frag;
			npp->p_cpg = opp->p_cpg;
		}
	}
 	nlp->d_checksum = 0;
 	nlp->d_checksum = dkcksum(nlp);
	*olp = *nlp;
	return (0);
}

/* encoding of disk minor numbers, should be elsewhere... */
#define dkunit(dev)		(minor(dev) >> 3)
#define dkpart(dev)		(minor(dev) & 07)
#define dkminor(unit, part)	(((unit) << 3) | (part))

/*
 * Write disk label back to device after modification.
 */
int
writedisklabel(dev, strat, lp, osdep)
	dev_t dev;
	void (*strat)();
	register struct disklabel *lp;
	struct cpu_disklabel *osdep;
{
	struct buf *bp;
	struct disklabel *dlp;
	int labelpart;
	int error = 0;

	labelpart = dkpart(dev);
	if (lp->d_partitions[labelpart].p_offset != 0) {
		if (lp->d_partitions[0].p_offset != 0)
			return (EXDEV);			/* not quite right */
		labelpart = 0;
	}
	bp = geteblk((int)lp->d_secsize);
	bp->b_dev = makedev(major(dev), dkminor(dkunit(dev), labelpart));
	bp->b_blkno = LABELSECTOR;
	bp->b_bcount = lp->d_secsize;
	bp->b_flags = B_READ;
	(*strat)(bp);
	if (error = biowait(bp))
		goto done;
	for (dlp = (struct disklabel *)bp->b_data;
	    dlp <= (struct disklabel *)
	      ((char *)bp->b_data + lp->d_secsize - sizeof(*dlp));
	    dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
		if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC &&
		    dkcksum(dlp) == 0) {
			*dlp = *lp;
			bp->b_flags = B_WRITE;
			(*strat)(bp);
			error = biowait(bp);
			goto done;
		}
	}
	error = ESRCH;
done:
	brelse(bp);
	return (error);
}