freebsd-dev/sys/geom/geom_bsd.c
2003-01-28 09:48:09 +00:00

939 lines
26 KiB
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.
* 3. The names of the authors may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* 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.
*
* $FreeBSD$
*
* This is the method for dealing with BSD disklabels. It has been
* extensively (by my standards at least) commented, in the vain hope that
* it will serve as the source in future copy&paste operations.
*/
#include <sys/param.h>
#ifndef _KERNEL
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <err.h>
#else
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/bio.h>
#include <sys/malloc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#endif
#include <sys/stdint.h>
#include <sys/md5.h>
#include <sys/errno.h>
#include <sys/disklabel.h>
#include <geom/geom.h>
#include <geom/geom_slice.h>
#define BSD_CLASS_NAME "BSD"
#define ALPHA_LABEL_OFFSET 64
/*
* Our private data about one instance. All the rest is handled by the
* slice code and stored in its softc, so this is just the stuff
* specific to BSD disklabels.
*/
struct g_bsd_softc {
off_t labeloffset;
off_t mbroffset;
off_t rawoffset;
struct disklabel ondisk;
struct disklabel inram;
u_char labelsum[16];
};
/*
* The next 4 functions isolate us from how the compiler lays out and pads
* "struct disklabel". We treat what we read from disk as a bytestream and
* explicitly convert it into a struct disklabel. This makes us compiler-
* endianness- and wordsize- agnostic.
* For now we only have little-endian formats to deal with.
*/
static void
g_bsd_ledec_partition(u_char *ptr, struct partition *d)
{
d->p_size = g_dec_le4(ptr + 0);
d->p_offset = g_dec_le4(ptr + 4);
d->p_fsize = g_dec_le4(ptr + 8);
d->p_fstype = ptr[12];
d->p_frag = ptr[13];
d->p_cpg = g_dec_le2(ptr + 14);
}
static void
g_bsd_ledec_disklabel(u_char *ptr, struct disklabel *d)
{
int i;
d->d_magic = g_dec_le4(ptr + 0);
d->d_type = g_dec_le2(ptr + 4);
d->d_subtype = g_dec_le2(ptr + 6);
bcopy(ptr + 8, d->d_typename, 16);
bcopy(ptr + 24, d->d_packname, 16);
d->d_secsize = g_dec_le4(ptr + 40);
d->d_nsectors = g_dec_le4(ptr + 44);
d->d_ntracks = g_dec_le4(ptr + 48);
d->d_ncylinders = g_dec_le4(ptr + 52);
d->d_secpercyl = g_dec_le4(ptr + 56);
d->d_secperunit = g_dec_le4(ptr + 60);
d->d_sparespertrack = g_dec_le2(ptr + 64);
d->d_sparespercyl = g_dec_le2(ptr + 66);
d->d_acylinders = g_dec_le4(ptr + 68);
d->d_rpm = g_dec_le2(ptr + 72);
d->d_interleave = g_dec_le2(ptr + 74);
d->d_trackskew = g_dec_le2(ptr + 76);
d->d_cylskew = g_dec_le2(ptr + 78);
d->d_headswitch = g_dec_le4(ptr + 80);
d->d_trkseek = g_dec_le4(ptr + 84);
d->d_flags = g_dec_le4(ptr + 88);
d->d_drivedata[0] = g_dec_le4(ptr + 92);
d->d_drivedata[1] = g_dec_le4(ptr + 96);
d->d_drivedata[2] = g_dec_le4(ptr + 100);
d->d_drivedata[3] = g_dec_le4(ptr + 104);
d->d_drivedata[4] = g_dec_le4(ptr + 108);
d->d_spare[0] = g_dec_le4(ptr + 112);
d->d_spare[1] = g_dec_le4(ptr + 116);
d->d_spare[2] = g_dec_le4(ptr + 120);
d->d_spare[3] = g_dec_le4(ptr + 124);
d->d_spare[4] = g_dec_le4(ptr + 128);
d->d_magic2 = g_dec_le4(ptr + 132);
d->d_checksum = g_dec_le2(ptr + 136);
d->d_npartitions = g_dec_le2(ptr + 138);
d->d_bbsize = g_dec_le4(ptr + 140);
d->d_sbsize = g_dec_le4(ptr + 144);
for (i = 0; i < MAXPARTITIONS; i++)
g_bsd_ledec_partition(ptr + 148 + 16 * i, &d->d_partitions[i]);
}
static void
g_bsd_leenc_partition(u_char *ptr, struct partition *d)
{
g_enc_le4(ptr + 0, d->p_size);
g_enc_le4(ptr + 4, d->p_offset);
g_enc_le4(ptr + 8, d->p_fsize);
ptr[12] = d->p_fstype;
ptr[13] = d->p_frag;
g_enc_le2(ptr + 14, d->p_cpg);
}
static void
g_bsd_leenc_disklabel(u_char *ptr, struct disklabel *d)
{
int i;
g_enc_le4(ptr + 0, d->d_magic);
g_enc_le2(ptr + 4, d->d_type);
g_enc_le2(ptr + 6, d->d_subtype);
bcopy(d->d_typename, ptr + 8, 16);
bcopy(d->d_packname, ptr + 24, 16);
g_enc_le4(ptr + 40, d->d_secsize);
g_enc_le4(ptr + 44, d->d_nsectors);
g_enc_le4(ptr + 48, d->d_ntracks);
g_enc_le4(ptr + 52, d->d_ncylinders);
g_enc_le4(ptr + 56, d->d_secpercyl);
g_enc_le4(ptr + 60, d->d_secperunit);
g_enc_le2(ptr + 64, d->d_sparespertrack);
g_enc_le2(ptr + 66, d->d_sparespercyl);
g_enc_le4(ptr + 68, d->d_acylinders);
g_enc_le2(ptr + 72, d->d_rpm);
g_enc_le2(ptr + 74, d->d_interleave);
g_enc_le2(ptr + 76, d->d_trackskew);
g_enc_le2(ptr + 78, d->d_cylskew);
g_enc_le4(ptr + 80, d->d_headswitch);
g_enc_le4(ptr + 84, d->d_trkseek);
g_enc_le4(ptr + 88, d->d_flags);
g_enc_le4(ptr + 92, d->d_drivedata[0]);
g_enc_le4(ptr + 96, d->d_drivedata[1]);
g_enc_le4(ptr + 100, d->d_drivedata[2]);
g_enc_le4(ptr + 104, d->d_drivedata[3]);
g_enc_le4(ptr + 108, d->d_drivedata[4]);
g_enc_le4(ptr + 112, d->d_spare[0]);
g_enc_le4(ptr + 116, d->d_spare[1]);
g_enc_le4(ptr + 120, d->d_spare[2]);
g_enc_le4(ptr + 124, d->d_spare[3]);
g_enc_le4(ptr + 128, d->d_spare[4]);
g_enc_le4(ptr + 132, d->d_magic2);
g_enc_le2(ptr + 136, d->d_checksum);
g_enc_le2(ptr + 138, d->d_npartitions);
g_enc_le4(ptr + 140, d->d_bbsize);
g_enc_le4(ptr + 144, d->d_sbsize);
for (i = 0; i < MAXPARTITIONS; i++)
g_bsd_leenc_partition(ptr + 148 + 16 * i, &d->d_partitions[i]);
}
static int
g_bsd_ondisk_size(void)
{
return (148 + 16 * MAXPARTITIONS);
}
/*
* For reasons which were valid and just in their days, FreeBSD/i386 uses
* absolute disk-addresses in disklabels. The way it works is that the
* p_offset field of all partitions have the first sector number of the
* disk slice added to them. This was hidden kernel-magic, userland did
* not see these offsets. These two functions subtract and add them
* while converting from the "ondisk" to the "inram" labels and vice
* versa.
*/
static void
ondisk2inram(struct g_bsd_softc *sc)
{
struct partition *ppp;
struct disklabel *dl;
int i;
sc->inram = sc->ondisk;
dl = &sc->inram;
/* Basic sanity-check needed to avoid mistakes. */
if (dl->d_magic != DISKMAGIC || dl->d_magic2 != DISKMAGIC)
return;
if (dl->d_npartitions > MAXPARTITIONS)
return;
sc->rawoffset = dl->d_partitions[RAW_PART].p_offset;
for (i = 0; i < dl->d_npartitions; i++) {
ppp = &dl->d_partitions[i];
if (ppp->p_size != 0 && ppp->p_offset < sc->rawoffset)
sc->rawoffset = 0;
}
if (sc->rawoffset > 0) {
for (i = 0; i < dl->d_npartitions; i++) {
ppp = &dl->d_partitions[i];
if (ppp->p_offset != 0)
ppp->p_offset -= sc->rawoffset;
}
}
dl->d_checksum = 0;
dl->d_checksum = dkcksum(&sc->inram);
}
static void
inram2ondisk(struct g_bsd_softc *sc)
{
struct partition *ppp;
int i;
sc->ondisk = sc->inram;
if (sc->mbroffset != 0)
sc->rawoffset = sc->mbroffset / sc->inram.d_secsize;
if (sc->rawoffset != 0) {
for (i = 0; i < sc->inram.d_npartitions; i++) {
ppp = &sc->ondisk.d_partitions[i];
if (ppp->p_size > 0)
ppp->p_offset += sc->rawoffset;
else
ppp->p_offset = 0;
}
}
sc->ondisk.d_checksum = 0;
sc->ondisk.d_checksum = dkcksum(&sc->ondisk);
}
/*
* Check that this looks like a valid disklabel, but be prepared
* to get any kind of junk. The checksum must be checked only
* after this function returns success to prevent a bogus d_npartitions
* value from tripping us up.
*/
static int
g_bsd_checklabel(struct disklabel *dl)
{
struct partition *ppp;
int i;
if (dl->d_magic != DISKMAGIC || dl->d_magic2 != DISKMAGIC)
return (EINVAL);
/*
* If the label specifies more partitions than we can handle
* we have to reject it: If people updated the label they would
* trash it, and that would break the checksum.
*/
if (dl->d_npartitions > MAXPARTITIONS)
return (EINVAL);
for (i = 0; i < dl->d_npartitions; i++) {
ppp = &dl->d_partitions[i];
/* Cannot extend past unit. */
if (ppp->p_size != 0 &&
ppp->p_offset + ppp->p_size > dl->d_secperunit) {
return (EINVAL);
}
}
return (0);
}
/*
* Modify our slicer to match proposed disklabel, if possible.
* First carry out all the simple checks, then lock topology
* and check that no open providers are affected negatively
* then carry out all the changes.
*
* NB: Returns with topology held only if successful return.
*/
static int
g_bsd_modify(struct g_geom *gp, struct disklabel *dl)
{
int i, error;
struct partition *ppp;
struct g_slicer *gsp;
struct g_consumer *cp;
u_int secsize, u;
off_t mediasize;
/* Basic check that this is indeed a disklabel. */
error = g_bsd_checklabel(dl);
if (error)
return (error);
/* Make sure the checksum is OK. */
if (dkcksum(dl) != 0)
return (EINVAL);
/* Get dimensions of our device. */
cp = LIST_FIRST(&gp->consumer);
secsize = cp->provider->sectorsize;
mediasize = cp->provider->mediasize;
#ifdef nolonger
/*
* The raw-partition must start at zero. We do not check that the
* size == mediasize because this is overly restrictive. We have
* already tested in g_bsd_checklabel() that it is not longer.
* XXX: RAW_PART is archaic anyway, and we should drop it.
*/
if (dl->d_partitions[RAW_PART].p_offset != 0)
return (EINVAL);
#endif
#ifdef notyet
/*
* Indications are that the d_secperunit is not correctly
* initialized in many cases, and since we don't need it
* for anything, we dont strictly need this test.
* Preemptive action to avoid confusing people in disklabel(8)
* may be in order.
*/
/* The label cannot claim a larger size than the media. */
if ((off_t)dl->d_secperunit * dl->d_secsize > mediasize)
return (EINVAL);
#endif
/* ... or a smaller sector size. */
if (dl->d_secsize < secsize)
return (EINVAL);
/* ... or a non-multiple sector size. */
if (dl->d_secsize % secsize != 0)
return (EINVAL);
g_topology_lock();
/* Don't munge open partitions. */
gsp = gp->softc;
for (i = 0; i < dl->d_npartitions; i++) {
ppp = &dl->d_partitions[i];
error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
(off_t)ppp->p_offset * dl->d_secsize,
(off_t)ppp->p_size * dl->d_secsize,
dl->d_secsize,
"%s%c", gp->name, 'a' + i);
if (error) {
g_topology_unlock();
return (error);
}
}
/* Look good, go for it... */
for (u = 0; u < gsp->nslice; u++) {
ppp = &dl->d_partitions[u];
g_slice_config(gp, u, G_SLICE_CONFIG_SET,
(off_t)ppp->p_offset * dl->d_secsize,
(off_t)ppp->p_size * dl->d_secsize,
dl->d_secsize,
"%s%c", gp->name, 'a' + u);
}
return (0);
}
/*
* Calculate a disklabel checksum for a little-endian byte-stream.
* We need access to the decoded disklabel because the checksum only
* covers the partition data for the first d_npartitions.
*/
static int
g_bsd_lesum(struct disklabel *dl, u_char *p)
{
u_char *pe;
uint16_t sum;
pe = p + 148 + 16 * dl->d_npartitions;
sum = 0;
while (p < pe) {
sum ^= g_dec_le2(p);
p += 2;
}
return (sum);
}
/*
* This is an internal helper function, called multiple times from the taste
* function to try to locate a disklabel on the disk. More civilized formats
* will not need this, as there is only one possible place on disk to look
* for the magic spot.
*/
static int
g_bsd_try(struct g_geom *gp, struct g_slicer *gsp, struct g_consumer *cp, int secsize, struct g_bsd_softc *ms, off_t offset)
{
int error;
u_char *buf;
struct disklabel *dl;
off_t secoff;
/*
* We need to read entire aligned sectors, and we assume that the
* disklabel does not span sectors, so one sector is enough.
*/
error = 0;
secoff = offset % secsize;
buf = g_read_data(cp, offset - secoff, secsize, &error);
if (buf == NULL || error != 0)
return (ENOENT);
/* Decode into our native format. */
dl = &ms->ondisk;
g_bsd_ledec_disklabel(buf + secoff, dl);
ondisk2inram(ms);
dl = &ms->inram;
/* Does it look like a label at all? */
if (g_bsd_checklabel(dl))
error = ENOENT;
/* ... and does the raw data have a good checksum? */
if (error == 0 && g_bsd_lesum(dl, buf + secoff) != 0)
error = ENOENT;
/* Remember to free the buffer g_read_data() gave us. */
g_free(buf);
/* If we had a label, record it properly. */
if (error == 0) {
gsp->frontstuff = 16 * secsize; /* XXX */
ms->labeloffset = offset;
g_topology_lock();
g_slice_conf_hot(gp, 0, offset, g_bsd_ondisk_size());
g_topology_unlock();
}
return (error);
}
/*
* Implement certain ioctls to modify disklabels with. This function
* is called by the event handler thread with topology locked as result
* of the g_call_me() in g_bsd_start(). It is not necessary to keep
* topology locked all the time but make sure to return with topology
* locked as well.
*/
static void
g_bsd_ioctl(void *arg)
{
struct bio *bp;
struct g_geom *gp;
struct g_slicer *gsp;
struct g_bsd_softc *ms;
struct disklabel *dl;
struct g_ioctl *gio;
struct g_consumer *cp;
u_char *buf;
off_t secoff;
u_int secsize;
int error, i;
uint64_t sum;
/* We don't need topology for now. */
g_topology_unlock();
/* 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. */
dl = gio->data;
/* Validate and modify our slice instance to match. */
error = g_bsd_modify(gp, dl); /* Picks up topology lock on success. */
if (error) {
g_topology_lock();
g_io_deliver(bp, error);
return;
}
/* Update our copy of the disklabel. */
ms->inram = *dl;
inram2ondisk(ms);
if (gio->cmd == DIOCSDINFO) {
g_io_deliver(bp, 0);
return;
}
KASSERT(gio->cmd == DIOCWDINFO, ("Unknown ioctl in g_bsd_ioctl"));
cp = LIST_FIRST(&gp->consumer);
/* Get sector size, we need it to read data. */
secsize = cp->provider->sectorsize;
secoff = ms->labeloffset % secsize;
buf = g_read_data(cp, ms->labeloffset - secoff, secsize, &error);
if (buf == NULL || error != 0) {
g_io_deliver(bp, error);
return;
}
dl = &ms->ondisk;
g_bsd_leenc_disklabel(buf + secoff, dl);
if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
sum = 0;
for (i = 0; i < 63; i++)
sum += g_dec_le8(buf + i * 8);
g_enc_le8(buf + 504, sum);
}
error = g_write_data(cp, ms->labeloffset - secoff, buf, secsize);
g_free(buf);
g_io_deliver(bp, error);
}
/*
* Rewrite the bootblock, which is BBSIZE bytes from the start of the disk.
* We punch down the disklabel where we expect it to be before writing.
*/
static int
g_bsd_diocbsdbb(dev_t dev, u_long cmd __unused, caddr_t data, int fflag __unused, struct thread *td __unused)
{
struct g_geom *gp;
struct g_slicer *gsp;
struct g_bsd_softc *ms;
struct disklabel *dl;
struct g_consumer *cp;
u_char *buf;
void *p;
u_int secsize;
int error, i;
uint64_t sum;
/* Get hold of the interesting bits from the bio. */
gp = (void *)dev;
gsp = gp->softc;
ms = gsp->softc;
/* The disklabel to set is the ioctl argument. */
buf = g_malloc(BBSIZE, 0);
p = *(void **)data;
error = copyin(p, buf, BBSIZE);
if (error) {
g_free(buf);
return (error);
}
/* The disklabel to set is the ioctl argument. */
dl = (void *)(buf + ms->labeloffset);
DROP_GIANT();
/* Validate and modify our slice instance to match. */
error = g_bsd_modify(gp, dl); /* Picks up topology lock on success. */
if (!error) {
cp = LIST_FIRST(&gp->consumer);
secsize = cp->provider->sectorsize;
dl = &ms->ondisk;
g_bsd_leenc_disklabel(buf + ms->labeloffset, dl);
if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
sum = 0;
for (i = 0; i < 63; i++)
sum += g_dec_le8(buf + i * 8);
g_enc_le8(buf + 504, sum);
}
error = g_write_data(cp, 0, buf, BBSIZE);
g_topology_unlock();
}
g_free(buf);
PICKUP_GIANT();
return (error);
}
/*
* If the user tries to overwrite our disklabel through an open partition
* or via a magicwrite config call, we end up here and try to prevent
* footshooting as best we can.
*/
static void
g_bsd_hotwrite(void *arg)
{
struct bio *bp;
struct g_geom *gp;
struct g_slicer *gsp;
struct g_slice *gsl;
struct g_bsd_softc *ms;
struct g_bsd_softc fake;
u_char *p;
int error;
bp = arg;
gp = bp->bio_to->geom;
gsp = gp->softc;
ms = gsp->softc;
gsl = &gsp->slices[bp->bio_to->index];
p = (u_char*)bp->bio_data + ms->labeloffset
- (bp->bio_offset + gsl->offset);
g_bsd_ledec_disklabel(p, &fake.ondisk);
ondisk2inram(&fake);
if (g_bsd_checklabel(&fake.inram)) {
g_io_deliver(bp, EPERM);
return;
}
if (g_bsd_lesum(&fake.ondisk, p) != 0) {
g_io_deliver(bp, EPERM);
return;
}
g_topology_unlock();
error = g_bsd_modify(gp, &fake.inram); /* May pick up topology. */
if (error) {
g_io_deliver(bp, EPERM);
g_topology_lock();
return;
}
/* Update our copy of the disklabel. */
ms->inram = fake.inram;
inram2ondisk(ms);
g_bsd_leenc_disklabel(p, &ms->ondisk);
g_slice_finish_hot(bp);
}
/*-
* This start routine is only called for non-trivial requests, all the
* trivial ones are handled autonomously by the slice code.
* For requests we handle here, we must call the g_io_deliver() on the
* bio, and return non-zero to indicate to the slice code that we did so.
* This code executes in the "DOWN" I/O path, this means:
* * No sleeping.
* * Don't grab the topology lock.
* * Don't call biowait, g_getattr(), g_setattr() or g_read_data()
*/
static int
g_bsd_start(struct bio *bp)
{
struct g_geom *gp;
struct g_bsd_softc *ms;
struct g_slicer *gsp;
struct g_ioctl *gio;
int error;
gp = bp->bio_to->geom;
gsp = gp->softc;
ms = gsp->softc;
switch(bp->bio_cmd) {
case BIO_READ:
/* We allow reading of our hot spots */
return (0);
case BIO_DELETE:
/* We do not allow deleting our hot spots */
return (EPERM);
case BIO_WRITE:
g_call_me(g_bsd_hotwrite, bp);
return (EJUSTRETURN);
case BIO_GETATTR:
if (g_handleattr(bp, "BSD::labelsum", ms->labelsum,
sizeof(ms->labelsum)))
return (1);
break;
case BIO_SETATTR:
break;
default:
KASSERT(0 == 1, ("Unknown bio_cmd in g_bsd_start (%d)",
bp->bio_cmd));
}
/* 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 DIOCGDINFO:
/* Return a copy of the disklabel to userland. */
bcopy(&ms->inram, gio->data, sizeof(ms->inram));
g_io_deliver(bp, 0);
return (1);
case DIOCBSDBB:
gio->func = g_bsd_diocbsdbb;
gio->dev = (void *)gp;
g_io_deliver(bp, EDIRIOCTL);
return (1);
case DIOCSDINFO:
case DIOCWDINFO:
/*
* 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_bsd_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);
}
}
/*
* Dump configuration information in XML format.
* Notice that the function is called once for the geom and once for each
* consumer and provider. We let g_slice_dumpconf() do most of the work.
*/
static void
g_bsd_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp)
{
struct g_bsd_softc *ms;
struct g_slicer *gsp;
gsp = gp->softc;
ms = gsp->softc;
g_slice_dumpconf(sb, indent, gp, cp, pp);
if (indent != NULL && pp == NULL && cp == NULL) {
sbuf_printf(sb, "%s<labeloffset>%jd</labeloffset>\n",
indent, (intmax_t)ms->labeloffset);
sbuf_printf(sb, "%s<rawoffset>%jd</rawoffset>\n",
indent, (intmax_t)ms->rawoffset);
sbuf_printf(sb, "%s<mbroffset>%jd</mbroffset>\n",
indent, (intmax_t)ms->mbroffset);
} else if (pp != NULL) {
if (indent == NULL)
sbuf_printf(sb, " ty %d",
ms->inram.d_partitions[pp->index].p_fstype);
else
sbuf_printf(sb, "%s<type>%d</type>\n", indent,
ms->inram.d_partitions[pp->index].p_fstype);
}
}
/*
* The taste function is called from the event-handler, with the topology
* lock already held and a provider to examine. The flags are unused.
*
* If flags == G_TF_NORMAL, the idea is to take a bite of the provider and
* if we find valid, consistent magic on it, build a geom on it.
* any magic bits which indicate that we should automatically put a BSD
* geom on it.
*
* There may be cases where the operator would like to put a BSD-geom on
* providers which do not meet all of the requirements. This can be done
* by instead passing the G_TF_INSIST flag, which will override these
* checks.
*
* The final flags value is G_TF_TRANSPARENT, which instructs the method
* to put a geom on top of the provider and configure it to be as transparent
* as possible. This is not really relevant to the BSD method and therefore
* not implemented here.
*/
static struct g_geom *
g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags)
{
struct g_geom *gp;
struct g_consumer *cp;
int error, i;
struct g_bsd_softc *ms;
struct disklabel *dl;
u_int secsize;
struct g_slicer *gsp;
MD5_CTX md5sum;
u_char hash[16];
g_trace(G_T_TOPOLOGY, "bsd_taste(%s,%s)", mp->name, pp->name);
g_topology_assert();
/* We don't implement transparent inserts. */
if (flags == G_TF_TRANSPARENT)
return (NULL);
/*
* BSD labels are a subclass of the general "slicing" topology so
* a lot of the work can be done by the common "slice" code.
* Create a geom with space for MAXPARTITIONS providers, one consumer
* and a softc structure for us. Specify the provider to attach
* the consumer to and our "start" routine for special requests.
* The provider is opened with mode (1,0,0) so we can do reads
* from it.
*/
gp = g_slice_new(mp, MAXPARTITIONS, pp, &cp, &ms,
sizeof(*ms), g_bsd_start);
if (gp == NULL)
return (NULL);
/*
* Now that we have attached to and opened our provider, we do
* not need the topology lock until we change the topology again
* next time.
*/
g_topology_unlock();
/*
* Fill in the optional details, in our case we have a dumpconf
* routine which the "slice" code should call at the right time
*/
gp->dumpconf = g_bsd_dumpconf;
/* Get the geom_slicer softc from the geom. */
gsp = gp->softc;
/*
* The do...while loop here allows us to have multiple escapes
* using a simple "break". This improves code clarity without
* ending up in deep nesting and without using goto or come from.
*/
do {
/*
* If the provider is an MBR we will only auto attach
* to type 165 slices in the G_TF_NORMAL case. We will
* attach to any other type.
*/
error = g_getattr("MBR::type", cp, &i);
if (!error) {
if (i != 165 && flags == G_TF_NORMAL)
break;
error = g_getattr("MBR::offset", cp, &ms->mbroffset);
if (error)
break;
}
/* Same thing if we are inside a PC98 */
error = g_getattr("PC98::type", cp, &i);
if (!error) {
if (i != 0xc494 && flags == G_TF_NORMAL)
break;
error = g_getattr("PC98::offset", cp, &ms->mbroffset);
if (error)
break;
}
/* Get sector size, we need it to read data. */
secsize = cp->provider->sectorsize;
if (secsize < 512)
break;
/* First look for a label at the start of the second sector. */
error = g_bsd_try(gp, gsp, cp, secsize, ms, secsize);
/* Next, look for alpha labels */
if (error)
error = g_bsd_try(gp, gsp, cp, secsize, ms,
ALPHA_LABEL_OFFSET);
/* If we didn't find a label, punt. */
if (error)
break;
/*
* In order to avoid recursively attaching to the same
* on-disk label (it's usually visible through the 'c'
* partition) we calculate an MD5 and ask if other BSD's
* below us love that label. If they do, we don't.
*/
dl = &ms->inram;
MD5Init(&md5sum);
MD5Update(&md5sum, (u_char *)dl, sizeof(dl));
MD5Final(ms->labelsum, &md5sum);
error = g_getattr("BSD::labelsum", cp, &hash);
if (!error && !strncmp(ms->labelsum, hash, sizeof(hash)))
break;
/*
* Process the found disklabel, and modify our "slice"
* instance to match it, if possible.
*/
error = g_bsd_modify(gp, dl); /* Picks up topology lock. */
if (!error)
g_topology_unlock();
break;
} while (0);
/* Success or failure, we can close our provider now. */
g_topology_lock();
error = g_access_rel(cp, -1, 0, 0);
/* If we have configured any providers, return the new geom. */
if (gsp->nprovider > 0)
return (gp);
/*
* ...else push the "self-destruct" button, by spoiling our own
* consumer. This triggers a call to g_std_spoiled which will
* dismantle what was setup.
*/
g_std_spoiled(cp);
return (NULL);
}
/* Finally, register with GEOM infrastructure. */
static struct g_class g_bsd_class = {
BSD_CLASS_NAME,
g_bsd_taste,
NULL,
G_CLASS_INITIALIZER
};
DECLARE_GEOM_CLASS(g_bsd_class, g_bsd);