freebsd/sys/i386/isa/diskslice_machdep.c

/*-
 * Copyright (c) 1994 Bruce D. Evans.
 * All rights reserved.
 *
 * 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. 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	7.16 (Berkeley) 5/4/91
 *	from: ufs_disksubr.c,v 1.8 1994/06/07 01:21:39 phk Exp $
 *	$Id: diskslice_machdep.c,v 1.5 1995/02/21 08:37:09 bde Exp $
 */

#include <stddef.h>
#include <sys/param.h>
#include <sys/buf.h>
#include <sys/disklabel.h>
#include <sys/diskslice.h>
#include <sys/malloc.h>
#include <sys/systm.h>

int
dsinit(dname, dev, strat, lp, sspp)
	char	*dname;
	dev_t	dev;
	d_strategy_t *strat;
	struct disklabel *lp;
	struct diskslices **sspp;
{
	struct buf *bp;
	u_char	*cp;
	struct dos_partition *dp;
	struct dos_partition *dp0;
	int	error;
	int	max_ncyls;
	int	max_nsectors;
	int	max_ntracks;
	char	partname[2];
	u_long	secpercyl;
	int	slice;
	char	*sname;
	struct diskslice *sp;
	struct diskslices *ssp;

	/*
	 * Allocate a dummy slices "struct" and initialize it to contain
	 * only an empty compatibility slice (pointing to itself) and a
	 * whole disk slice (covering the disk as described by the label).
	 * If there is an error, then the dummy struct becomes final.
	 */
	ssp = malloc(offsetof(struct diskslices, dss_slices)
		     + BASE_SLICE * sizeof *sp, M_DEVBUF, M_WAITOK);
	*sspp = ssp;
	ssp->dss_first_bsd_slice = COMPATIBILITY_SLICE;
	ssp->dss_nslices = BASE_SLICE;
	sp = &ssp->dss_slices[0];
	bzero(sp, BASE_SLICE * sizeof *sp);
	sp[WHOLE_DISK_SLICE].ds_size = lp->d_secperunit;

	/* Read master boot record. */
	bp = geteblk((int)lp->d_secsize);
	bp->b_dev = dkmodpart(dkmodslice(dev, WHOLE_DISK_SLICE), RAW_PART);
	bp->b_blkno = DOSBBSECTOR;
	bp->b_bcount = lp->d_secsize;
	bp->b_flags = B_BUSY | B_READ;
	(*strat)(bp);
	if (biowait(bp) != 0) {
		error = EIO;
		goto done;
	}

	/* Weakly verify it. */
	cp = bp->b_un.b_addr;
	if (cp[0x1FE] != 0x55 || cp[0x1FF] != 0xAA) {
		error = EINVAL;
		goto done;
	}

	/* Guess the geometry. */
	/*
	 * TODO:
	 * Perhaps skip entries with 0 size.
	 * Perhaps only look at entries of type DOSPTYP_386BSD.
	 */
	max_ncyls = 0;
	max_nsectors = 0;
	max_ntracks = 0;
	dp0 = (struct dos_partition *)(cp + DOSPARTOFF);
	for (dp = dp0, slice = BASE_SLICE; slice < BASE_SLICE + NDOSPART;
	     dp++, slice++) {
		int nsectors;
		int ntracks;

		max_ncyls = DPCYL(dp->dp_ecyl, dp->dp_esect);
		if (max_ncyls < max_ncyls)
			max_ncyls = max_ncyls;
		nsectors = DPSECT(dp->dp_esect);
		if (max_nsectors < nsectors)
			max_nsectors = nsectors;
		ntracks = dp->dp_ehd + 1;
		if (max_ntracks < ntracks)
			max_ntracks = ntracks;
	}

	/* Check the geometry. */
	/*
	 * TODO:
	 * As above.
	 * Check for overlaps.
	 * Check against d_secperunit if the latter is reliable.
	 */
	error = 0;
	secpercyl = max_nsectors * max_ntracks;
	for (dp = dp0, slice = BASE_SLICE; slice < BASE_SLICE + NDOSPART;
	     dp++, slice++) {
		u_long esector;
		u_long esector1;
		u_long ssector;

		if (dp->dp_scyl == 0 && dp->dp_shd == 0 && dp->dp_ssect == 0
		    && dp->dp_start == 0 && dp->dp_size == 0)
			continue;
		ssector = DPSECT(dp->dp_ssect) - 1 + dp->dp_shd * max_nsectors
			  + DPCYL(dp->dp_scyl, dp->dp_ssect) * secpercyl;
		esector = DPSECT(dp->dp_esect) - 1 + dp->dp_ehd * max_nsectors
			  + DPCYL(dp->dp_ecyl, dp->dp_esect) * secpercyl;
		esector1 = dp->dp_start + dp->dp_size - 1;
		sname = dsname(dname, dkunit(dev), slice, RAW_PART, partname);
		if (ssector != dp->dp_start || esector != esector1)
			error = EINVAL;
#if 1
		else
			printf("%s: start %lu, end = %lu, size %lu: OK\n",
			       sname, ssector, esector, dp->dp_size);
		if (ssector != dp->dp_start)
			printf("%s: C/H/S start %lu != start %lu: invalid\n",
			       sname, ssector, dp->dp_start);
		if (esector != esector1)
			printf("%s: C/H/S end %lu != end %lu: invalid\n",
			       sname, esector, esector1);
#endif
	}
	if (error != 0)
		goto done;

	/*
	 * Accept the DOS partition table.
	 * First adjust the label (we have been careful not to change it
	 * before we can guarantee success).
	 */
	if (secpercyl != 0) {
		u_long	secperunit;

		lp->d_nsectors = max_nsectors;
		lp->d_ntracks = max_ntracks;
		lp->d_secpercyl = secpercyl;
		secperunit = secpercyl * max_ncyls;
		if (lp->d_secperunit < secperunit)
			lp->d_secperunit = secperunit;
	}

	/*
	 * Free the dummy slices "struct" and allocate a real new one.
	 * Initialize special slices as above.
	 */
	free(ssp, M_DEVBUF);
	ssp = malloc(offsetof(struct diskslices, dss_slices)
		     + (BASE_SLICE + NDOSPART) * sizeof *sp,
		     M_DEVBUF, M_WAITOK);
	*sspp = ssp;
	ssp->dss_first_bsd_slice = COMPATIBILITY_SLICE;
	sp = &ssp->dss_slices[0];
	bzero(sp, (BASE_SLICE + NDOSPART) * sizeof *sp);
	sp[WHOLE_DISK_SLICE].ds_size = lp->d_secperunit;

	/* Initialize normal slices. */
	sp += BASE_SLICE;
	for (dp = dp0, slice = BASE_SLICE; slice < BASE_SLICE + NDOSPART;
	     dp++, slice++, sp++) {
		if (dp->dp_typ == DOSPTYP_386BSD
		    && ssp->dss_first_bsd_slice == COMPATIBILITY_SLICE) {
			ssp->dss_first_bsd_slice = slice;
			ssp->dss_slices[COMPATIBILITY_SLICE].ds_offset
			    = dp->dp_start;
			ssp->dss_slices[COMPATIBILITY_SLICE].ds_size
			    = dp->dp_size;
		}
		sp->ds_offset = dp->dp_start;
		sp->ds_size = dp->dp_size;
#if 0
		lp->d_subtype |= (lp->d_subtype & 3)
				 | (slice - BASE_SLICE) | DSTYPE_INDOSPART;
#endif
	}

	/*
	 * We're not handling extended partitions yet, so there are always
	 * BASE_SLICE + NDOSPART slices altogether.
	 */
	ssp->dss_nslices = BASE_SLICE + NDOSPART;

done:
	bp->b_flags = B_INVAL | B_AGE;
	brelse(bp);
	if (error == EINVAL)
		error = 0;
	return (error);
}