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Implement ioctls for tampering with sector0.

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This commit is contained in:
Poul-Henning Kamp 2002-12-29 14:59:24 +00:00
parent 4fe7f0f9c0
commit f8cfa0dbaf
1 changed files with 84 additions and 27 deletions
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111
sys/geom/geom_mbr.c
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@ -106,17 +106,26 @@ g_enc_dos_partition(u_char *ptr, struct dos_partition *d)
struct g_mbr_softc {
int type [NDOSPART];
struct dos_partition dospart[NDOSPART];
u_char sec0[512];
};
static int
g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, struct dos_partition *dp)
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 ((!bcmp(dp, historical_bogus_partition_table,
sizeof historical_bogus_partition_table)) ||
(!bcmp(dp, historical_bogus_partition_table_fixed,
@ -162,9 +171,43 @@ g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, struct dos_partition *dp
(off_t)dp[i].dp_start << 9ULL, l[i], 512,
"%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)
{
@ -172,7 +215,8 @@ g_mbr_start(struct bio *bp)
struct g_geom *gp;
struct g_mbr_softc *mp;
struct g_slicer *gsp;
int idx;
struct g_ioctl *gio;
int idx, error;
pp = bp->bio_to;
idx = pp->index;
@ -186,6 +230,40 @@ g_mbr_start(struct bio *bp)
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);
}
@ -225,8 +303,7 @@ g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist)
{
struct g_geom *gp;
struct g_consumer *cp;
int error, i;
struct dos_partition dp[NDOSPART];
int error;
struct g_mbr_softc *ms;
struct g_slicer *gsp;
u_int fwsectors, sectorsize;
@ -253,30 +330,10 @@ g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist)
buf = g_read_data(cp, 0, sectorsize, &error);
if (buf == NULL || error != 0)
break;
if (buf[0x1fe] != 0x55 && buf[0x1ff] != 0xaa) {
g_free(buf);
break;
}
for (i = 0; i < NDOSPART; i++)
g_dec_dos_partition(
buf + DOSPARTOFF + i * sizeof(struct dos_partition),
dp + i);
g_free(buf);
if (bcmp(dp, historical_bogus_partition_table,
sizeof historical_bogus_partition_table) == 0) {
if (bootverbose)
printf("Ignoring known bogus MBR #0\n");
break;
}
if (bcmp(dp, historical_bogus_partition_table_fixed,
sizeof historical_bogus_partition_table_fixed) == 0) {
if (bootverbose)
printf("Ignoring known bogus MBR #1\n");
break;
}
g_topology_lock();
g_mbr_modify(gp, ms, dp);
g_mbr_modify(gp, ms, buf);
g_topology_unlock();
g_free(buf);
break;
}
g_topology_lock();