path: root/sys/geom/geom_mbr.c

/*-
 * Copyright (c) 2002 Poul-Henning Kamp
 * Copyright (c) 2002 Networks Associates Technology, Inc.
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
 * and NAI Labs, the Security Research Division of Network Associates, Inc.
 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
 * DARPA CHATS research program.
 *
 * 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 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 AUTHOR 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.
 *
 * $FreeBSD$
 */

#include <sys/param.h>
#include <sys/errno.h>
#ifndef _KERNEL
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <sys/param.h>
#include <stdlib.h>
#include <err.h>
#else
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/bio.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#endif

#include <sys/diskmbr.h>
#include <sys/sbuf.h>
#include <geom/geom.h>
#include <geom/geom_slice.h>

#define MBR_CLASS_NAME "MBR"
#define MBREXT_CLASS_NAME "MBREXT"

static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
};
static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, },
};

static void
g_mbr_print(int i, struct dos_partition *dp)
{

	printf("[%d] f:%02x typ:%d", i, dp->dp_flag, dp->dp_typ);
	printf(" s(CHS):%d/%d/%d", dp->dp_scyl, dp->dp_shd, dp->dp_ssect);
	printf(" e(CHS):%d/%d/%d", dp->dp_ecyl, dp->dp_ehd, dp->dp_esect);
	printf(" s:%d l:%d\n", dp->dp_start, dp->dp_size);
}

static void
g_dec_dos_partition(u_char *ptr, struct dos_partition *d)
{

	d->dp_flag = ptr[0];
	d->dp_shd = ptr[1];
	d->dp_ssect = ptr[2];
	d->dp_scyl = ptr[3];
	d->dp_typ = ptr[4];
	d->dp_ehd = ptr[5];
	d->dp_esect = ptr[6];
	d->dp_ecyl = ptr[7];
	d->dp_start = g_dec_le4(ptr + 8);
	d->dp_size = g_dec_le4(ptr + 12);
}

#if 0
static void
g_enc_dos_partition(u_char *ptr, struct dos_partition *d)
{

	ptr[0] = d->dp_flag;
	ptr[1] = d->dp_shd;
	ptr[2] = d->dp_ssect;
	ptr[3] = d->dp_scyl;
	ptr[4] = d->dp_typ;
	ptr[5] = d->dp_ehd;
	ptr[6] = d->dp_esect;
	ptr[7] = d->dp_ecyl;
	g_enc_le4(ptr + 8, d->dp_start);
	g_enc_le4(ptr + 12, d->dp_size);
}
#endif

struct g_mbr_softc {
	int		type [NDOSPART];
	u_int		sectorsize;
	u_char		sec0[512];
};

static int
g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, u_char *sec0)
{
	int i, error;
	off_t l[NDOSPART];
	struct dos_partition ndp[NDOSPART], *dp;

	g_topology_assert();

	if (sec0[0x1fe] != 0x55 && sec0[0x1ff] != 0xaa)
		return (EBUSY);

	dp = ndp;
	for (i = 0; i < NDOSPART; i++) {
		g_dec_dos_partition(
		    sec0 + DOSPARTOFF + i * sizeof(struct dos_partition),
		    dp + i);
		if (bootverbose)
			g_mbr_print(i, dp + i);
	}
	if ((!bcmp(dp, historical_bogus_partition_table,
	    sizeof historical_bogus_partition_table)) ||
	    (!bcmp(dp, historical_bogus_partition_table_fixed,
	    sizeof historical_bogus_partition_table_fixed))) {
		/*
		 * We will not allow people to write these from "the inside",
		 * Since properly selfdestructing takes too much code.  If 
		 * people really want to do this, they cannot have any
		 * providers of this geom open, and in that case they can just
		 * as easily overwrite the MBR in the parent device.
		 */
		return(EBUSY);
	}
	for (i = 0; i < NDOSPART; i++) {
		/* 
		 * A Protective MBR (PMBR) has a single partition of
		 * type 0xEE spanning the whole disk. Such a MBR
		 * protects a GPT on the disk from MBR tools that
		 * don't know anything about GPT. We're interpreting
		 * it a bit more loosely: any partition of type 0xEE
		 * is to be skipped as it doesn't contain any data
		 * that we should care about. We still allow other
		 * partitions to be present in the MBR. A PMBR will
		 * be handled correctly anyway.
		 */
		if (dp[i].dp_typ == 0xee)
			l[i] = 0;
		else if (dp[i].dp_flag != 0 && dp[i].dp_flag != 0x80)
			l[i] = 0;
		else if (dp[i].dp_typ == 0)
			l[i] = 0;
		else
			l[i] = (off_t)dp[i].dp_size * ms->sectorsize;
		error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
		    (off_t)dp[i].dp_start * ms->sectorsize, l[i],
		    ms->sectorsize, "%ss%d", gp->name, 1 + i);
		if (error)
			return (error);
	}
	for (i = 0; i < NDOSPART; i++) {
		ms->type[i] = dp[i].dp_typ;
		g_slice_config(gp, i, G_SLICE_CONFIG_SET,
		    (off_t)dp[i].dp_start * ms->sectorsize, l[i],
		    ms->sectorsize, "%ss%d", gp->name, 1 + i);
	}
	bcopy(sec0, ms->sec0, 512);
	return (0);
}

static void
g_mbr_ioctl(void *arg)
{
	struct bio *bp;
	struct g_geom *gp;
	struct g_slicer *gsp;
	struct g_mbr_softc *ms;
	struct g_ioctl *gio;
	struct g_consumer *cp;
	u_char *sec0;
	int error;

	/* Get hold of the interesting bits from the bio. */
	bp = arg;
	gp = bp->bio_to->geom;
	gsp = gp->softc;
	ms = gsp->softc;
	gio = (struct g_ioctl *)bp->bio_data;

	/* The disklabel to set is the ioctl argument. */
	sec0 = gio->data;

	error = g_mbr_modify(gp, ms, sec0);
	if (error) {
		g_io_deliver(bp, error);
		return;
	}
	cp = LIST_FIRST(&gp->consumer);
	error = g_write_data(cp, 0, sec0, 512);
	g_io_deliver(bp, error);
}


static int
g_mbr_start(struct bio *bp)
{
	struct g_provider *pp;
	struct g_geom *gp;
	struct g_mbr_softc *mp;
	struct g_slicer *gsp;
	struct g_ioctl *gio;
	int idx, error;

	pp = bp->bio_to;
	idx = pp->index;
	gp = pp->geom;
	gsp = gp->softc;
	mp = gsp->softc;
	if (bp->bio_cmd == BIO_GETATTR) {
		if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
			return (1);
		if (g_handleattr_off_t(bp, "MBR::offset",
		    gsp->slices[idx].offset))
			return (1);
	}

	/* We only handle ioctl(2) requests of the right format. */
	if (strcmp(bp->bio_attribute, "GEOM::ioctl"))
		return (0);
	else if (bp->bio_length != sizeof(*gio))
		return (0);

	/* Get hold of the ioctl parameters. */
	gio = (struct g_ioctl *)bp->bio_data;

	switch (gio->cmd) {
	case DIOCGMBR:
		/* Return a copy of the disklabel to userland. */
		bcopy(mp->sec0, gio->data, 512);
		g_io_deliver(bp, 0);
		return (1);
	case DIOCSMBR:
		/*
		 * These we cannot do without the topology lock and some
		 * some I/O requests.  Ask the event-handler to schedule
		 * us in a less restricted environment.
		 */
		error = g_call_me(g_mbr_ioctl, bp);
		if (error)
			g_io_deliver(bp, error);
		/*
		 * We must return non-zero to indicate that we will deal
		 * with this bio, even though we have not done so yet.
		 */
		return (1);
	default:
		return (0);
	}

	return (0);
}

static void
g_mbr_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
{
	struct g_mbr_softc *mp;
	struct g_slicer *gsp;

	gsp = gp->softc;
	mp = gsp->softc;
	g_slice_dumpconf(sb, indent, gp, cp, pp);
	if (pp != NULL) {
		if (indent == NULL)
			sbuf_printf(sb, " ty %d", mp->type[pp->index]);
		else
			sbuf_printf(sb, "%s<type>%d</type>\n", indent,
			    mp->type[pp->index]);
	}
}

static struct g_geom *
g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist)
{
	struct g_geom *gp;
	struct g_consumer *cp;
	int error;
	struct g_mbr_softc *ms;
	struct g_slicer *gsp;
	u_int fwsectors, sectorsize;
	u_char *buf;

	g_trace(G_T_TOPOLOGY, "mbr_taste(%s,%s)", mp->name, pp->name);
	g_topology_assert();
	gp = g_slice_new(mp, NDOSPART, pp, &cp, &ms, sizeof *ms, g_mbr_start);
	if (gp == NULL)
		return (NULL);
	gsp = gp->softc;
	g_topology_unlock();
	gp->dumpconf = g_mbr_dumpconf;
	while (1) {	/* a trick to allow us to use break */
		if (gp->rank != 2 && insist == 0)
			break;
		error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
		if (error)
			fwsectors = 17;
		sectorsize = cp->provider->sectorsize;
		if (sectorsize < 512)
			break;
		ms->sectorsize = sectorsize;
		gsp->frontstuff = sectorsize * fwsectors;
		buf = g_read_data(cp, 0, sectorsize, &error);
		if (buf == NULL || error != 0)
			break;
		g_topology_lock();
		g_mbr_modify(gp, ms, buf);
		g_topology_unlock();
		g_free(buf);
		break;
	}
	g_topology_lock();
	g_access_rel(cp, -1, 0, 0);
	if (LIST_EMPTY(&gp->provider)) {
		g_std_spoiled(cp);
		return (NULL);
	}
	return (gp);
}

static struct g_class g_mbr_class	= {
	MBR_CLASS_NAME,
	g_mbr_taste,
	NULL,
	G_CLASS_INITIALIZER
};

DECLARE_GEOM_CLASS(g_mbr_class, g_mbr);

#define NDOSEXTPART		32
struct g_mbrext_softc {
	int		type [NDOSEXTPART];
};

static int
g_mbrext_start(struct bio *bp)
{
	struct g_provider *pp;
	struct g_geom *gp;
	struct g_mbrext_softc *mp;
	struct g_slicer *gsp;
	int idx;

	pp = bp->bio_to;
	idx = pp->index;
	gp = pp->geom;
	gsp = gp->softc;
	mp = gsp->softc;
	if (bp->bio_cmd == BIO_GETATTR) {
		if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
			return (1);
	}
	return (0);
}

static void
g_mbrext_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
{
	struct g_mbrext_softc *mp;
	struct g_slicer *gsp;

	g_slice_dumpconf(sb, indent, gp, cp, pp);
	gsp = gp->softc;
	mp = gsp->softc;
	if (pp != NULL) {
		if (indent == NULL)
			sbuf_printf(sb, " ty %d", mp->type[pp->index]);
		else
			sbuf_printf(sb, "%s<type>%d</type>\n", indent,
			    mp->type[pp->index]);
	}
}

static struct g_geom *
g_mbrext_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
{
	struct g_geom *gp;
	struct g_consumer *cp;
	int error, i, slice;
	struct g_mbrext_softc *ms;
	off_t off;
	u_char *buf;
	struct dos_partition dp[4];
	u_int fwsectors, sectorsize;
	struct g_slicer *gsp;

	g_trace(G_T_TOPOLOGY, "g_mbrext_taste(%s,%s)", mp->name, pp->name);
	g_topology_assert();
	if (strcmp(pp->geom->class->name, MBR_CLASS_NAME))
		return (NULL);
	gp = g_slice_new(mp, NDOSEXTPART, pp, &cp, &ms, sizeof *ms, g_mbrext_start);
	if (gp == NULL)
		return (NULL);
	gsp = gp->softc;
	g_topology_unlock();
	gp->dumpconf = g_mbrext_dumpconf;
	off = 0;
	slice = 0;
	while (1) {	/* a trick to allow us to use break */
		error = g_getattr("MBR::type", cp, &i);
		if (error || (i != DOSPTYP_EXT && i != DOSPTYP_EXTLBA))
			break;
		error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
		if (error)
			fwsectors = 17;
		sectorsize = cp->provider->sectorsize;
		if (sectorsize != 512)
			break;
		gsp->frontstuff = sectorsize * fwsectors;
		for (;;) {
			buf = g_read_data(cp, off, sectorsize, &error);
			if (buf == NULL || error != 0)
				break;
			if (buf[0x1fe] != 0x55 && buf[0x1ff] != 0xaa)
				break;
			for (i = 0; i < NDOSPART; i++) 
				g_dec_dos_partition(
				    buf + DOSPARTOFF + 
				    i * sizeof(struct dos_partition), dp + i);
			g_free(buf);
			printf("MBREXT Slice %d on %s:\n", slice + 5, gp->name);
			g_mbr_print(0, dp);
			g_mbr_print(1, dp + 1);
			if ((dp[0].dp_flag & 0x7f) == 0 &&
			     dp[0].dp_size != 0 && dp[0].dp_typ != 0) {
				g_topology_lock();
				g_slice_config(gp, slice, G_SLICE_CONFIG_SET,
				    (((off_t)dp[0].dp_start) << 9ULL) + off,
				    ((off_t)dp[0].dp_size) << 9ULL,
				    sectorsize,
				    "%*.*s%d",
				    strlen(gp->name) - 1,
				    strlen(gp->name) - 1,
				    gp->name,
				    slice + 5);
				g_topology_unlock();
				ms->type[slice] = dp[0].dp_typ;
				slice++;
			}
			if (dp[1].dp_flag != 0)
				break;
			if (dp[1].dp_typ != DOSPTYP_EXT)
				break;
			if (dp[1].dp_size == 0)
				break;
			off = ((off_t)dp[1].dp_start) << 9ULL;
		}
		break;
	}
	g_topology_lock();
	g_access_rel(cp, -1, 0, 0);
	if (LIST_EMPTY(&gp->provider)) {
		g_std_spoiled(cp);
		return (NULL);
	}
	return (gp);
}


static struct g_class g_mbrext_class	= {
	MBREXT_CLASS_NAME,
	g_mbrext_taste,
	NULL,
	G_CLASS_INITIALIZER
};

DECLARE_GEOM_CLASS(g_mbrext_class, g_mbrext);