/* $NetBSD: dkwedge_bsdlabel.c,v 1.25 2020/04/11 16:00:34 jdolecek Exp $ */

/* $NetBSD: dkwedge_bsdlabel.c,v 1.25 2020/04/11 16:00:34 jdolecek Exp $ */

/*-
* Copyright (c) 2004 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/

/*
* Adapted from kern/subr_disk_mbr.c:
*
* 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
*/

/*
* 4.4BSD disklabel support for disk wedges
*
* Here is the basic search algorithm in use here:
*
* For historical reasons, we scan for x86-style MBR partitions looking
* for a MBR_PTYPE_NETBSD (or MBR_PTYPE_386BSD) partition. The first
* 4.4BSD disklabel found in the 2nd sector of such a partition is used.
* We assume that the 4.4BSD disklabel describes all partitions on the
* disk; we do not use any partition information from the MBR partition
* table.
*
* If that fails, then we fall back on a table of known locations for
* various platforms.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: dkwedge_bsdlabel.c,v 1.25 2020/04/11 16:00:34 jdolecek Exp $");

#include <sys/param.h>
#ifdef _KERNEL
#include <sys/systm.h>
#endif
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/disk.h>
#include <sys/vnode.h>
#include <sys/buf.h>

#include <sys/bootblock.h>
#include <sys/disklabel.h>

#define BSD44_MBR_LABELSECTOR 1

#define DISKLABEL_SIZE(x) \
(offsetof(struct disklabel, d_partitions) + \
(sizeof(struct partition) * (x)))

/*
* Note the smallest MAXPARTITIONS was 8, so we allow a disklabel
* that size to be locted at the end of the sector.
*/
#define DISKLABEL_MINSIZE DISKLABEL_SIZE(8)

/*
* Table of known platform-specific disklabel locations.
*/
static const struct disklabel_location {
daddr_t label_sector; /* sector containing label */
size_t label_offset; /* byte offset of label in sector */
} disklabel_locations[] = {
{ 0, 0 }, /* mvme68k, next68k */
{ 0, 64 }, /* algor, alpha, amiga, amigappc, evbmips, evbppc,
luna68k, mac68k, macppc, news68k, newsmips,
pc532, pdp11, pmax, vax, x68k */
{ 0, 128 }, /* sparc, sun68k */
{ 1, 0 }, /* amd64, arc, arm, bebox, cobalt, evbppc, hppa,
hpcarm, hpcmips, i386, ibmnws, mipsco, mvmeppc,
ofppc, playstation2, pmppc, prep, sandpoint,
sbmips, sgimips, sh3 */
/* XXX atari is weird */
{ 2, 0 }, /* cesfic, hp300 */

{ -1, 0 },
};

#define SCAN_CONTINUE 0
#define SCAN_FOUND 1
#define SCAN_ERROR 2

typedef struct mbr_args {
struct disk *pdk;
struct vnode *vp;
struct buf *bp;
int error;
uint32_t secsize;
} mbr_args_t;

static const char *
bsdlabel_fstype_to_str(uint8_t fstype)
{
const char *str;

/*
* For each type known to FSTYPE_DEFN (from <sys/disklabel.h>),
* a suitable case branch will convert the type number to a string.
*/
switch (fstype) {
#define FSTYPE_TO_STR_CASE(tag, number, name, fsck, mount) \
case __CONCAT(FS_,tag): str = __CONCAT(DKW_PTYPE_,tag); break;
FSTYPE_DEFN(FSTYPE_TO_STR_CASE)
#undef FSTYPE_TO_STR_CASE
default: str = NULL; break;
}

return (str);
}

static void
swap_disklabel(struct disklabel *lp)
{
int i;

#define SWAP16(x) lp->x = bswap16(lp->x)
#define SWAP32(x) lp->x = bswap32(lp->x)

SWAP32(d_magic);
SWAP16(d_type);
SWAP16(d_subtype);
SWAP32(d_secsize);
SWAP32(d_nsectors);
SWAP32(d_ntracks);
SWAP32(d_ncylinders);
SWAP32(d_secpercyl);
SWAP32(d_secperunit);
SWAP16(d_sparespertrack);
SWAP16(d_sparespercyl);
SWAP32(d_acylinders);
SWAP16(d_rpm);
SWAP16(d_interleave);
SWAP16(d_trackskew);
SWAP16(d_cylskew);
SWAP32(d_headswitch);
SWAP32(d_trkseek);
SWAP32(d_flags);

for (i = 0; i < NDDATA; i++)
SWAP32(d_drivedata[i]);
for (i = 0; i < NSPARE; i++)
SWAP32(d_spare[i]);

SWAP32(d_magic2);
SWAP16(d_checksum);
SWAP16(d_npartitions);
SWAP32(d_bbsize);
SWAP32(d_sbsize);

for (i = 0; i < lp->d_npartitions; i++) {
SWAP32(d_partitions[i].p_size);
SWAP32(d_partitions[i].p_offset);
SWAP32(d_partitions[i].p_fsize);
SWAP16(d_partitions[i].p_cpg);
}

#undef SWAP16
#undef SWAP32
}

/*
* Add wedges for a valid NetBSD disklabel.
*/
static void
addwedges(const mbr_args_t *a, const struct disklabel *lp)
{
int error, i;

for (i = 0; i < lp->d_npartitions; i++) {
struct dkwedge_info dkw;
const struct partition *p;
const char *ptype;

p = &lp->d_partitions[i];

if (p->p_fstype == FS_UNUSED)
continue;

memset(&dkw, 0, sizeof(dkw));

ptype = bsdlabel_fstype_to_str(p->p_fstype);
if (ptype == NULL)
snprintf(dkw.dkw_ptype, sizeof(dkw.dkw_ptype),
"unknown#%u", p->p_fstype);
else
strlcpy(dkw.dkw_ptype, ptype, sizeof(dkw.dkw_ptype));

strlcpy(dkw.dkw_parent, a->pdk->dk_name,
sizeof(dkw.dkw_parent));
dkw.dkw_offset = p->p_offset;
dkw.dkw_size = p->p_size;

/*
* If the label defines a name, append the partition
* letter and use it as the wedge name.
* Otherwise use historical disk naming style
* wedge names.
*/
if (lp->d_packname[0] &&
strcmp(lp->d_packname,"fictitious") != 0) {
snprintf((char *)&dkw.dkw_wname, sizeof(dkw.dkw_wname),
"%.*s/%c", (int)sizeof(dkw.dkw_wname)-3,
lp->d_packname, 'a' + i);
} else {
snprintf((char *)&dkw.dkw_wname, sizeof(dkw.dkw_wname),
"%s%c", a->pdk->dk_name, 'a' + i);
}

error = dkwedge_add(&dkw);
if (error == EEXIST)
aprint_error("%s: wedge named '%s' already "
"exists, manual intervention required\n",
a->pdk->dk_name, dkw.dkw_wname);
else if (error)
aprint_error("%s: error %d adding partition "
"%d type %d\n", a->pdk->dk_name, error,
i, p->p_fstype);
}
}

static int
validate_label(mbr_args_t *a, daddr_t label_sector, size_t label_offset)
{
struct disklabel *lp;
void *lp_lim;
int error, swapped;
uint16_t npartitions;

error = dkwedge_read(a->pdk, a->vp, label_sector, a->bp->b_data,
a->secsize);
if (error) {
aprint_error("%s: unable to read BSD disklabel @ %" PRId64
", error = %d\n", a->pdk->dk_name, label_sector, error);
a->error = error;
return (SCAN_ERROR);
}

/*
* We ignore label_offset; this seems to have not been used
* consistently in the old code, requiring us to do the search
* in the sector.
*/
lp = a->bp->b_data;
lp_lim = (char *)a->bp->b_data + a->secsize - DISKLABEL_MINSIZE;
for (;; lp = (void *)((char *)lp + sizeof(uint32_t))) {
if ((char *)lp > (char *)lp_lim)
return (SCAN_CONTINUE);
label_offset = (size_t)((char *)lp - (char *)a->bp->b_data);
if (lp->d_magic != DISKMAGIC || lp->d_magic2 != DISKMAGIC) {
if (lp->d_magic != bswap32(DISKMAGIC) ||
lp->d_magic2 != bswap32(DISKMAGIC))
continue;
/* Label is in the other byte order. */
swapped = 1;
} else
swapped = 0;

npartitions = (swapped) ? bswap16(lp->d_npartitions)
: lp->d_npartitions;

/* Validate label length. */
if ((char *)lp + DISKLABEL_SIZE(npartitions) >
(char *)a->bp->b_data + a->secsize) {
aprint_error("%s: BSD disklabel @ "
"%" PRId64 "+%zd has bogus partition count (%u)\n",
a->pdk->dk_name, label_sector, label_offset,
npartitions);
continue;
}

/*
* We have validated the partition count. Checksum it.
* Note that we purposefully checksum before swapping
* the byte order.
*/
if (dkcksum_sized(lp, npartitions) != 0) {
aprint_error("%s: BSD disklabel @ %" PRId64
"+%zd has bad checksum\n", a->pdk->dk_name,
label_sector, label_offset);
continue;
}
/* Put the disklabel in the right order. */
if (swapped)
swap_disklabel(lp);
addwedges(a, lp);
return (SCAN_FOUND);
}
}

static int
scan_mbr(mbr_args_t *a, int (*actn)(mbr_args_t *, struct mbr_partition *,
int, u_int))
{
struct mbr_partition ptns[MBR_PART_COUNT];
struct mbr_partition *dp;
struct mbr_sector *mbr;
u_int ext_base, this_ext, next_ext;
int i, rval;
#ifdef COMPAT_386BSD_MBRPART
int dp_386bsd = -1;
#endif

ext_base = 0;
this_ext = 0;
for (;;) {
a->error = dkwedge_read(a->pdk, a->vp, this_ext, a->bp->b_data,
a->secsize);
if (a->error) {
aprint_error("%s: unable to read MBR @ %u, "
"error = %d\n", a->pdk->dk_name, this_ext,
a->error);
return (SCAN_ERROR);
}

mbr = a->bp->b_data;
if (mbr->mbr_magic != htole16(MBR_MAGIC))
return (SCAN_CONTINUE);

/* Copy data out of buffer so action can use the buffer. */
memcpy(ptns, &mbr->mbr_parts, sizeof(ptns));

/* Looks for NetBSD partition. */
next_ext = 0;
dp = ptns;
for (i = 0; i < MBR_PART_COUNT; i++, dp++) {
if (dp->mbrp_type == 0)
continue;
if (MBR_IS_EXTENDED(dp->mbrp_type)) {
next_ext = le32toh(dp->mbrp_start);
continue;
}
#ifdef COMPAT_386BSD_MBRPART
if (dp->mbrp_type == MBR_PTYPE_386BSD) {
/*
* If more than one matches, take last,
* as NetBSD install tool does.
*/
if (this_ext == 0)
dp_386bsd = i;
continue;
}
#endif
rval = (*actn)(a, dp, i, this_ext);
if (rval != SCAN_CONTINUE)
return (rval);
}
if (next_ext == 0)
break;
if (ext_base == 0) {
ext_base = next_ext;
next_ext = 0;
}
next_ext += ext_base;
if (next_ext <= this_ext)
break;
this_ext = next_ext;
}
#ifdef COMPAT_386BSD_MBRPART
if (this_ext == 0 && dp_386bsd != -1)
return ((*actn)(a, &ptns[dp_386bsd], dp_386bsd, 0));
#endif
return (SCAN_CONTINUE);
}

static int
look_netbsd_part(mbr_args_t *a, struct mbr_partition *dp, int slot,
u_int ext_base)
{
int ptn_base = ext_base + le32toh(dp->mbrp_start);
int rval;

if (
#ifdef COMPAT_386BSD_MBRPART
dp->mbrp_type == MBR_PTYPE_386BSD ||
#endif
dp->mbrp_type == MBR_PTYPE_NETBSD) {
rval = validate_label(a, ptn_base + BSD44_MBR_LABELSECTOR, 0);

/* If we got a NetBSD label, look no further. */
if (rval == SCAN_FOUND)
return (rval);
}

return (SCAN_CONTINUE);
}

static int
dkwedge_discover_bsdlabel(struct disk *pdk, struct vnode *vp)
{
mbr_args_t a;
const struct disklabel_location *dl;
int rval;

a.pdk = pdk;
a.secsize = DEV_BSIZE << pdk->dk_blkshift;
a.vp = vp;
a.bp = geteblk(a.secsize);
a.error = 0;

/* MBR search. */
rval = scan_mbr(&a, look_netbsd_part);
if (rval != SCAN_CONTINUE) {
if (rval == SCAN_FOUND)
a.error = 0; /* found it, wedges installed */
goto out;
}

/* Known location search. */
for (dl = disklabel_locations; dl->label_sector != -1; dl++) {
rval = validate_label(&a, dl->label_sector, dl->label_offset);
if (rval != SCAN_CONTINUE) {
if (rval == SCAN_FOUND)
a.error = 0; /* found it, wedges installed */
goto out;
}
}

/* No NetBSD disklabel found. */
a.error = ESRCH;
out:
brelse(a.bp, 0);
return (a.error);
}

#ifdef _KERNEL
DKWEDGE_DISCOVERY_METHOD_DECL(BSD44, 5, dkwedge_discover_bsdlabel);
#endif