/*	$NetBSD: disksubr.c,v 1.4 2019/04/17 20:46:38 skrll Exp $	*/

/*	$OpenBSD: disksubr.c,v 1.6 2000/10/18 21:00:34 mickey Exp $	*/

/*
 * Copyright (c) 1999 Michael Shalayeff
 * Copyright (c) 1997 Niklas Hallqvist
 * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
 * All rights reserved.
 *
 * 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. 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.
 *
 *	@(#)ufs_disksubr.c	7.16 (Berkeley) 5/4/91
 */

/*
 * Copyright (c) 1996 Theo de Raadt.  All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

/*
 * This disksubr.c module started to take its present form on OpenBSD/alpha
 * but it was always thought it should be made completely MI and not need to
 * be in that alpha-specific tree at all.
 *
 * XXX HPUX disklabel is not understood yet.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: disksubr.c,v 1.4 2019/04/17 20:46:38 skrll Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/device.h>
#include <sys/disklabel.h>
#include <sys/syslog.h>
#include <sys/disk.h>

const char *readliflabel(struct buf *, void (*)(struct buf *),
    struct disklabel *, struct cpu_disklabel *, int *, int *, int);
const char *readbsdlabel(struct buf *, void (*)(struct buf *), int,
    int, int, struct disklabel *, int);

/*
 * Try to read a standard BSD disklabel at a certain sector.
 */
const char *
readbsdlabel(struct buf *bp, void (*strat)(struct buf *), int cyl, int sec,
    int off, struct disklabel *lp, int spoofonly)
{
	struct disklabel *dlp;
	const char *msg = NULL;
	uint16_t cksum;

	/* don't read the on-disk label if we are in spoofed-only mode */
	if (spoofonly)
		return (NULL);

	bp->b_blkno = sec;
	bp->b_cylinder = cyl;
	bp->b_bcount = lp->d_secsize;
	bp->b_cflags = BC_BUSY;
	bp->b_flags = B_READ;
	bp->b_oflags = 0;
	(*strat)(bp);

	/* if successful, locate disk label within block and validate */
	if (biowait(bp)) {
		/* XXX we return the faked label built so far */
		msg = "disk label I/O error";
		return (msg);
	}

	/*
	 * If off is negative, search until the end of the sector for
	 * the label, otherwise, just look at the specific location
	 * we're given.
	 */
	dlp = (struct disklabel *)((char *)bp->b_data + (off >= 0 ? off : 0));
	do {
		if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
			if (msg == NULL)
				msg = "no disk label";
		} else {
			cksum = dkcksum(dlp);
			if (dlp->d_npartitions > MAXPARTITIONS || cksum != 0) {
				msg = "disk label corrupted";
			} else {
				*lp = *dlp;
				msg = NULL;
				break;
			}
		}
		if (off >= 0)
			break;
		dlp = (struct disklabel *)((char *)dlp + sizeof(int32_t));
	} while (dlp <= (struct disklabel *)((char *)bp->b_data +
		 lp->d_secsize - sizeof(*dlp)));
	return (msg);
}

/*
 * Attempt to read a disk label from a device
 * using the indicated strategy routine.
 * The label must be partly set up before this:
 * secpercyl, secsize and anything required for a block i/o read
 * operation in the driver's strategy/start routines
 * must be filled in before calling us.
 *
 * Returns null on success and an error string on failure.
 */
const char *
readdisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
    struct cpu_disklabel *osdep)
{
	int spoofonly = 0;
	struct buf *bp = NULL;
	const char *msg = "no disk label";
	int i;
	struct disklabel fallbacklabel;

	/* minimal requirements for archetypal disk label */
	if (lp->d_secsize == 0)
		lp->d_secsize = DEV_BSIZE;
	if (lp->d_secperunit == 0)
		lp->d_secperunit = 0x1fffffff;
	if (lp->d_secpercyl == 0)
		return "invalid geometry";

	lp->d_npartitions = RAW_PART + 1;
	for (i = 0; i < RAW_PART; i++) {
		lp->d_partitions[i].p_size = 0;
		lp->d_partitions[i].p_offset = 0;
	}
	if (lp->d_partitions[i].p_size == 0)
		lp->d_partitions[i].p_size = 0x1fffffff;
	lp->d_partitions[i].p_offset = 0;
	fallbacklabel = *lp;

	/* get a buffer and initialize it */
	bp = geteblk((int)lp->d_secsize);
	bp->b_dev = dev;

	msg = readliflabel(bp, strat, lp, osdep, 0, 0, spoofonly);

#if defined(CD9660)
	if (msg && iso_disklabelspoof(dev, strat, lp) == 0)
		msg = NULL;
#endif

	/* If there was an error, still provide a decent fake one.  */
	if (msg)
		*lp = fallbacklabel;

	if (bp) {
		brelse(bp, BC_INVAL);
	}
	return (msg);
}


const char *
readliflabel(struct buf *bp, void (*strat)(struct buf *), struct disklabel *lp,
    struct cpu_disklabel *osdep, int *partoffp, int *cylp, int spoofonly)
{
	int fsoff;

	/* read LIF volume header */
	bp->b_blkno = btodb(HPPA_LIF_VOLSTART);
	bp->b_bcount = lp->d_secsize;
	bp->b_cflags = BC_BUSY;
	bp->b_flags = B_READ;
	bp->b_cylinder = btodb(HPPA_LIF_VOLSTART) / lp->d_secpercyl;
	(*strat)(bp);

	if (biowait(bp)) {
		if (partoffp)
			*partoffp = -1;
		return "LIF volume header I/O error";
	}

	memcpy(&osdep->lifvol, bp->b_data, sizeof(struct hppa_lifvol));
	if (osdep->lifvol.vol_id != HPPA_LIF_VOL_ID) {
		fsoff = 0;
	} else {
		struct buf *dbp;
		struct hppa_lifdir *p;

		dbp = geteblk(lp->d_secsize);
		dbp->b_dev = bp->b_dev;

		/* read LIF directory */
		dbp->b_blkno = btodb(HPPA_LIF_DIRSTART);
		dbp->b_bcount = lp->d_secsize;
		dbp->b_cflags = BC_BUSY;
		dbp->b_flags = B_READ;
		dbp->b_cylinder = (HPPA_LIF_DIRSTART) / lp->d_secpercyl;

		(*strat)(dbp);

		if (biowait(dbp)) {
			if (partoffp)
				*partoffp = -1;
			brelse(dbp, BC_INVAL);

			return "LIF directory I/O error";
		}

		memcpy(osdep->lifdir, dbp->b_data, HPPA_LIF_DIRSIZE);
		brelse(dbp, BC_INVAL);
		/* scan for LIF_DIR_FS dir entry */
		for (fsoff = -1,  p = &osdep->lifdir[0];
		     fsoff < 0 && p < &osdep->lifdir[HPPA_LIF_NUMDIR]; p++)
			if (p->dir_type == HPPA_LIF_DIR_FS)
				fsoff = hppa_lifstodb(p->dir_addr);

		/* if no suitable lifdir entry found assume 0 */
		if (fsoff < 0)
			fsoff = 0;
	}

	if (partoffp)
		*partoffp = fsoff;

	return readbsdlabel(bp, strat, 0,  fsoff + LABELSECTOR, LABELOFFSET,
	    lp, spoofonly);
}

/*
 * Write disk label back to device after modification.
 */
int
writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
    struct cpu_disklabel *osdep)
{
	const char *msg = "no disk label";
	struct buf *bp;
	struct disklabel dl;
	struct cpu_disklabel cdl;
	int labeloffset, error, partoff = 0, cyl = 0;

	/* get a buffer and initialize it */
	bp = geteblk((int)lp->d_secsize);
	bp->b_dev = dev;

	/*
	 * I once played with the thought of using osdep->label{tag,sector}
	 * as a cache for knowing where (and what) to write.  However, now I
	 * think it might be useful to reprobe if someone has written
	 * a newer disklabel of another type with disklabel(8) and -r.
	 */
	dl = *lp;
	msg = readliflabel(bp, strat, &dl, &cdl, &partoff, &cyl, 0);
	labeloffset = LABELOFFSET;

	if (msg) {
		if (partoff == -1)
			return EIO;

		/* Write it in the regular place with native byte order. */
		labeloffset = LABELOFFSET;
		bp->b_blkno = partoff + LABELSECTOR;
		bp->b_cylinder = cyl;
		bp->b_bcount = lp->d_secsize;
	}

	*(struct disklabel *)((char *)bp->b_data + labeloffset) = *lp;

	bp->b_cflags = BC_BUSY;
	bp->b_flags = B_WRITE;
	(*strat)(bp);
	error = biowait(bp);

	brelse(bp, BC_INVAL);
	return (error);
}