/*
* Attempt to read a disk label from a device
* using the indicated strategy routine.
* The label must be partly set up before this:
* secpercyl, secsize and anything required for a block i/o read
* operation in the driver's strategy/start routines
* must be filled in before calling us.
*
* Returns null on success and an error string on failure.
*/
const char *
readdisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
struct cpu_disklabel *osdep)
{
int spoofonly = 0;
struct buf *bp = NULL;
const char *msg = "no disk label";
int i;
struct disklabel fallbacklabel;
/* minimal requirements for archetypal disk label */
if (lp->d_secsize == 0)
lp->d_secsize = DEV_BSIZE;
if (lp->d_secperunit == 0)
lp->d_secperunit = 0x1fffffff;
if (lp->d_secpercyl == 0)
return "invalid geometry";
lp->d_npartitions = RAW_PART + 1;
for (i = 0; i < RAW_PART; i++) {
lp->d_partitions[i].p_size = 0;
lp->d_partitions[i].p_offset = 0;
}
if (lp->d_partitions[i].p_size == 0)
lp->d_partitions[i].p_size = 0x1fffffff;
lp->d_partitions[i].p_offset = 0;
fallbacklabel = *lp;
/* get a buffer and initialize it */
bp = geteblk((int)lp->d_secsize);
bp->b_dev = dev;
msg = readliflabel(bp, strat, lp, osdep, 0, 0, spoofonly);
#if defined(CD9660)
if (msg && iso_disklabelspoof(dev, strat, lp) == 0)
msg = NULL;
#endif
/* If there was an error, still provide a decent fake one. */
if (msg)
*lp = fallbacklabel;
if (bp) {
brelse(bp, BC_INVAL);
}
return (msg);
}
/*
* Write disk label back to device after modification.
*/
int
writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
struct cpu_disklabel *osdep)
{
const char *msg = "no disk label";
struct buf *bp;
struct disklabel dl;
struct cpu_disklabel cdl;
int labeloffset, error, partoff = 0, cyl = 0;
/* get a buffer and initialize it */
bp = geteblk((int)lp->d_secsize);
bp->b_dev = dev;
/*
* I once played with the thought of using osdep->label{tag,sector}
* as a cache for knowing where (and what) to write. However, now I
* think it might be useful to reprobe if someone has written
* a newer disklabel of another type with disklabel(8) and -r.
*/
dl = *lp;
msg = readliflabel(bp, strat, &dl, &cdl, &partoff, &cyl, 0);
labeloffset = LABELOFFSET;
if (msg) {
if (partoff == -1)
return EIO;
/* Write it in the regular place with native byte order. */
labeloffset = LABELOFFSET;
bp->b_blkno = partoff + LABELSECTOR;
bp->b_cylinder = cyl;
bp->b_bcount = lp->d_secsize;
}
*(struct disklabel *)((char *)bp->b_data + labeloffset) = *lp;
bp->b_cflags = BC_BUSY;
bp->b_flags = B_WRITE;
(*strat)(bp);
error = biowait(bp);
brelse(bp, BC_INVAL);
return (error);
}
/*
* Write disk label back to device after modification.
*/
int
writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp)
{
int error = EIO, partoff = -1;
int offset;
struct disklabel *dlp;
struct buf *bp = NULL;
/* get a buffer and initialize it */
bp = geteblk((int)lp->d_secsize);
bp->b_dev = dev;
if (readliflabel(bp, strat, lp, &partoff, 1) == 0) {
bp->b_blkno = partoff + LABELSECTOR;
offset = LABELOFFSET;
} else if (readdoslabel(bp, strat, lp, &partoff, 1) == 0) {
bp->b_blkno = DL_BLKTOSEC(lp, partoff + DOS_LABELSECTOR) *
DL_BLKSPERSEC(lp);
offset = DL_BLKOFFSET(lp, partoff + DOS_LABELSECTOR);
} else
goto done;
/* Read it in, slap the new label in, and write it back out */
bp->b_bcount = lp->d_secsize;
CLR(bp->b_flags, B_READ | B_WRITE | B_DONE);
SET(bp->b_flags, B_BUSY | B_READ | B_RAW);
(*strat)(bp);
if ((error = biowait(bp)) != 0)
goto done;
dlp = (struct disklabel *)(bp->b_data + offset);
*dlp = *lp;
CLR(bp->b_flags, B_READ | B_WRITE | B_DONE);
SET(bp->b_flags, B_BUSY | B_WRITE | B_RAW);
(*strat)(bp);
error = biowait(bp);
done:
if (bp) {
bp->b_flags |= B_INVAL;
brelse(bp);
}
disk_change = 1;
return (error);
}
/*
* Attempt to read a disk label from a device
* using the indicated strategy routine.
* The label must be partly set up before this:
* secpercyl, secsize and anything required for a block i/o read
* operation in the driver's strategy/start routines
* must be filled in before calling us.
*/
int
readdisklabel(dev_t dev, void (*strat)(struct buf *),
struct disklabel *lp, int spoofonly)
{
struct buf *bp = NULL;
int error;
if ((error = initdisklabel(lp)))
goto done;
/* get a buffer and initialize it */
bp = geteblk((int)lp->d_secsize);
bp->b_dev = dev;
error = readliflabel(bp, strat, lp, NULL, spoofonly);
if (error == 0)
goto done;
error = readdoslabel(bp, strat, lp, NULL, spoofonly);
if (error == 0)
goto done;
#if defined(CD9660)
error = iso_disklabelspoof(dev, strat, lp);
if (error == 0)
goto done;
#endif
#if defined(UDF)
error = udf_disklabelspoof(dev, strat, lp);
if (error == 0)
goto done;
#endif
done:
if (bp) {
bp->b_flags |= B_INVAL;
brelse(bp);
}
disk_change = 1;
return (error);
}
