/*
* 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, int flag)
{
struct bio *bp;
struct g_geom *gp;
struct g_slicer *gsp;
struct g_slice *gsl;
struct g_bsd_softc *ms;
u_char *p;
int error;
g_topology_assert();
/*
* We should never get canceled, because that would amount to a removal
* of the geom while there was outstanding I/O requests.
*/
KASSERT(flag != EV_CANCEL, ("g_bsd_hotwrite cancelled"));
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);
error = g_bsd_modify(gp, p);
if (error) {
g_io_deliver(bp, EPERM);
return;
}
g_slice_finish_hot(bp);
}
static void
g_bsd_callconfig(void *arg, int flag)
{
struct h0h0 *hp;
hp = arg;
hp->error = g_bsd_modify(hp->gp, hp->label);
if (!hp->error)
hp->error = g_bsd_writelabel(hp->gp, NULL);
}
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;
u_int secsize;
struct g_slicer *gsp;
u_char hash[16];
MD5_CTX md5sum;
struct uuid uuid;
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);
/* 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;
}
/* Same thing if we are inside a GPT */
error = g_getattr("GPT::type", cp, &uuid);
if (!error) {
if (memcmp(&uuid, &freebsd_slice, sizeof(uuid)) != 0 &&
flags == G_TF_NORMAL)
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);
/*
* If sector size is not 512 the label still can be at
* offset 512, not at the start of the second sector. At least
* it's true for labels created by the FreeBSD's bsdlabel(8).
*/
if (error && secsize != HISTORIC_LABEL_OFFSET)
error = g_bsd_try(gp, gsp, cp, secsize, ms,
HISTORIC_LABEL_OFFSET);
/* 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.
*/
MD5Init(&md5sum);
MD5Update(&md5sum, ms->label, sizeof(ms->label));
MD5Final(ms->labelsum, &md5sum);
error = g_getattr("BSD::labelsum", cp, &hash);
if (!error && !bcmp(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, ms->label);
} while (0);
/* Success or failure, we can close our provider now. */
g_access(cp, -1, 0, 0);
/* If we have configured any providers, return the new geom. */
if (gsp->nprovider > 0) {
g_slice_conf_hot(gp, 0, ms->labeloffset, LABELSIZE,
G_SLICE_HOT_ALLOW, G_SLICE_HOT_DENY, G_SLICE_HOT_CALL);
gsp->hot = g_bsd_hotwrite;
return (gp);
}
/*
* ...else push the "self-destruct" button, by spoiling our own
* consumer. This triggers a call to g_slice_spoiled which will
* dismantle what was setup.
*/
g_slice_spoiled(cp);
return (NULL);
}
/*-
* 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_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td)
{
struct g_geom *gp;
struct g_bsd_softc *ms;
struct g_slicer *gsp;
u_char *label;
int error;
gp = pp->geom;
gsp = gp->softc;
ms = gsp->softc;
switch(cmd) {
case DIOCGDINFO:
/* Return a copy of the disklabel to userland. */
bsd_disklabel_le_dec(ms->label, data, MAXPARTITIONS);
return(0);
case DIOCBSDBB: {
struct g_consumer *cp;
u_char *buf;
void *p;
int error, i;
uint64_t sum;
if (!(fflag & FWRITE))
return (EPERM);
/* The disklabel to set is the ioctl argument. */
buf = g_malloc(BBSIZE, M_WAITOK);
p = *(void **)data;
error = copyin(p, buf, BBSIZE);
if (!error) {
/* XXX: Rude, but supposedly safe */
DROP_GIANT();
g_topology_lock();
/* Validate and modify our slice instance to match. */
error = g_bsd_modify(gp, buf + ms->labeloffset);
if (!error) {
cp = LIST_FIRST(&gp->consumer);
if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
sum = 0;
for (i = 0; i < 63; i++)
sum += le64dec(buf + i * 8);
le64enc(buf + 504, sum);
}
error = g_write_data(cp, 0, buf, BBSIZE);
}
g_topology_unlock();
PICKUP_GIANT();
}
g_free(buf);
return (error);
}
case DIOCSDINFO:
case DIOCWDINFO: {
if (!(fflag & FWRITE))
return (EPERM);
label = g_malloc(LABELSIZE, M_WAITOK);
/* The disklabel to set is the ioctl argument. */
bsd_disklabel_le_enc(label, data);
DROP_GIANT();
g_topology_lock();
/* Validate and modify our slice instance to match. */
error = g_bsd_modify(gp, label);
if (error == 0 && cmd == DIOCWDINFO)
error = g_bsd_writelabel(gp, NULL);
g_topology_unlock();
PICKUP_GIANT();
g_free(label);
return(error);
}
default:
return (ENOIOCTL);
}
}
