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authorphk <phk@FreeBSD.org>2002-12-02 20:23:54 +0000
committerphk <phk@FreeBSD.org>2002-12-02 20:23:54 +0000
commitbf720d1bf7acd15326c5af3d2e3de21840d56cdf (patch)
treeb22c48ba4d2ae63ae7e453aff1961064c2e5fd9e /sys/geom/geom_bsd.c
parent08185d6b24389fb9fd0169df1777d2260c978b01 (diff)
downloadFreeBSD-src-bf720d1bf7acd15326c5af3d2e3de21840d56cdf.zip
FreeBSD-src-bf720d1bf7acd15326c5af3d2e3de21840d56cdf.tar.gz
Use the hotspot code to prevent people from overwriting their disklabel
with stuff which would ruin the day for any open parititons. Approved by: re
Diffstat (limited to 'sys/geom/geom_bsd.c')
-rw-r--r--sys/geom/geom_bsd.c101
1 files changed, 90 insertions, 11 deletions
diff --git a/sys/geom/geom_bsd.c b/sys/geom/geom_bsd.c
index f3e1af5..f44eb76 100644
--- a/sys/geom/geom_bsd.c
+++ b/sys/geom/geom_bsd.c
@@ -198,6 +198,12 @@ g_bsd_leenc_disklabel(u_char *ptr, struct disklabel *d)
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
@@ -418,7 +424,7 @@ g_bsd_lesum(struct disklabel *dl, u_char *p)
*/
static int
-g_bsd_try(struct g_slicer *gsp, struct g_consumer *cp, int secsize, struct g_bsd_softc *ms, off_t offset)
+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;
@@ -456,6 +462,9 @@ g_bsd_try(struct g_slicer *gsp, struct g_consumer *cp, int secsize, struct g_bsd
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);
}
@@ -535,6 +544,52 @@ g_bsd_ioctl(void *arg)
g_io_deliver(bp, 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_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;
+ p = bp->bio_data + ms->labeloffset - bp->bio_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.
@@ -558,6 +613,23 @@ g_bsd_start(struct bio *bp)
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:
+ 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"))
@@ -707,16 +779,23 @@ g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags)
* attach to any other type (BSD was handles above)
*/
error = g_getattr("MBR::type", cp, &i);
- if (!error && i != 165 && flags == G_TF_NORMAL)
- break;
+ 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 && i != 0xc494 && flags == G_TF_NORMAL)
- break;
-
- ms->mbroffset = 0;
- g_getattr("MBR::offset", cp, &ms->mbroffset);
- g_getattr("PC98::offset", cp, &ms->mbroffset);
+ 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;
@@ -724,11 +803,11 @@ g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags)
break;
/* First look for a label at the start of the second sector. */
- error = g_bsd_try(gsp, cp, secsize, ms, secsize);
+ error = g_bsd_try(gp, gsp, cp, secsize, ms, secsize);
/* Next, look for alpha labels */
if (error)
- error = g_bsd_try(gsp, cp, secsize, ms,
+ error = g_bsd_try(gp, gsp, cp, secsize, ms,
ALPHA_LABEL_OFFSET);
/* If we didn't find a label, punt. */
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