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From: julian@tfs.com (Julian Elischer)
Subject: that patch for mounting unlabeled disks
Message-ID: <Cuz1IF.E9v@tfs.com>
Organization: TRW Financial Systems
Date: Tue, 23 Aug 1994 04:51:50 GMT
Lines: 250
Well, soemone found the thing that was getting me, and
I really do look silly
here it is again, and I plead stupidity and an old compiler.
I will upgrade imediatly to one that gives me
the appropriate messages,
anyhow,
here we go for the 4th (and hopefully last) time.
notice the two casts to (char) that have appeared in
the comparisons to bytes 510 and 511 of the MBR.
apparently this always evaluated to 1 (I still
don't understand why it went right for me here)
-------------cut here-----------------
*** ufs_disksubr.c.orig Sun Aug 21 22:51:21 1994
--- ufs_disksubr.c Mon Aug 22 14:04:07 1994
***************
*** 177,182 ****
--- 177,184 ----
struct disklabel *dlp;
char *msg = NULL;
int cyl, dospartoff, i;
+ int pseudopart = 4; /* we fill in pseudoparts from e through h*/
+ int seenBSD = 0;
/* minimal requirements for archtypal disk label */
if (lp->d_secperunit == 0)
***************
*** 185,190 ****
--- 187,198 ----
if (lp->d_partitions[0].p_size == 0)
lp->d_partitions[0].p_size = 0x1fffffff;
lp->d_partitions[0].p_offset = 0;
+ lp->d_partitions[1].p_size = 0;
+ lp->d_partitions[1].p_offset = 0;
+ lp->d_partitions[2].p_size = 0;
+ lp->d_partitions[2].p_offset = 0;
+ lp->d_partitions[3].p_size = 0;
+ lp->d_partitions[3].p_offset = 0;
/* obtain buffer to probe drive with */
bp = geteblk((int)lp->d_secsize);
***************
*** 205,246 ****
bp->b_cylin = DOSBBSECTOR / lp->d_secpercyl;
(*strat)(bp);
! /* if successful, wander through dos partition table */
if (biowait(bp)) {
msg = "dos partition I/O error";
goto done;
! } else {
! /* XXX how do we check veracity/bounds of this? */
! bcopy(bp->b_un.b_addr + DOSPARTOFF, dp,
! NDOSPART * sizeof(*dp));
! for (i = 0; i < NDOSPART; i++, dp++)
! /* is this ours? */
! if (dp->dp_size &&
! dp->dp_typ == DOSPTYP_386BSD
! && dospartoff == 0) {
! /* need sector address for SCSI/IDE,
! cylinder for ESDI/ST506/RLL */
dospartoff = dp->dp_start;
! cyl = DPCYL(dp->dp_scyl, dp->dp_ssect);
!
! /* update disklabel with details */
lp->d_partitions[0].p_size =
dp->dp_size;
lp->d_partitions[0].p_offset =
dp->dp_start;
- lp->d_ntracks = dp->dp_ehd + 1;
- lp->d_nsectors = DPSECT(dp->dp_esect);
- lp->d_subtype |= (lp->d_subtype & 3)
- + i | DSTYPE_INDOSPART;
- lp->d_secpercyl = lp->d_ntracks *
- lp->d_nsectors;
}
}
!
}
! /* next, dig out disk label */
bp->b_blkno = dospartoff + LABELSECTOR;
bp->b_cylin = cyl;
bp->b_bcount = lp->d_secsize;
--- 213,313 ----
bp->b_cylin = DOSBBSECTOR / lp->d_secpercyl;
(*strat)(bp);
! /*
! * if we failed in the read, give up.
! */
if (biowait(bp)) {
msg = "dos partition I/O error";
goto done;
! }
! /*
! * If there seems to be BIOS bootblock and partition table
! * in that block, then try interpret it, otherwise
! * give up and use whatever we have synthesised so far
! */
! if ((bp->b_un.b_addr[510] != (char) 0x55)
! ||(bp->b_un.b_addr[511] != (char) 0xaa)) {
! msg = "Disk has no Fdisk partitions";
! goto done;
! }
! /* XXX how do we check veracity/bounds of this? */
! bcopy(bp->b_un.b_addr + DOSPARTOFF, dp,
! NDOSPART * sizeof(*dp));
! /*
! * We set up the last 4 partitions in the
! * disklabel to reflect the DOS partitions
! * In case we never find a disklabel, in which
! * case this information will be all we have
! * but it might be all we need to access a DOS
! * partition.
! */
! for (i = 0; i < NDOSPART; i++, dp++,pseudopart++) {
!
! /*
! * Set this DOS part into the disklabel
! */
! lp->d_partitions[pseudopart].p_size =
! dp->dp_size;
! lp->d_partitions[pseudopart].p_offset =
! dp->dp_start;
! /*
! * If we haven't seen a *BSD partition then
! * check if this is a valid part..
! * if it is it may be the best we are going to
! * to see, so take note of it to deduce a
! * geometry in case we never find a disklabel.
! */
! if (dp->dp_size && (seenBSD == 0)) {
! if( dp->dp_typ == DOSPTYP_386BSD) {
! /*
! * If it IS our part, then we
! * need sector address for
! * SCSI/IDE, cylinder for
! * ESDI/ST506/RLL
! */
dospartoff = dp->dp_start;
! seenBSD = 1;
! cyl = DPCYL(dp->dp_scyl,
! dp->dp_ssect);
!
! /*
! * update disklabel with
! * details for reading the REAL
! * disklabel it it exists
! */
lp->d_partitions[0].p_size =
dp->dp_size;
lp->d_partitions[0].p_offset =
dp->dp_start;
}
+ /*
+ * Try deduce the geometry, working
+ * on the principle that this
+ * partition PROBABLY ends on a
+ * cylinder boundary.
+ * This is really a kludge, but we are
+ * forced into it by the PC's design.
+ */
+ lp->d_ntracks = dp->dp_ehd + 1;
+ lp->d_nsectors = DPSECT(dp->dp_esect);
+ lp->d_subtype |= (lp->d_subtype & 3)
+ + i | DSTYPE_INDOSPART;
+ lp->d_secpercyl = lp->d_ntracks *
+ lp->d_nsectors;
+ }
}
! lp->d_npartitions = 8;
}
! /*
! * If we haven't seen a BSD partition, give up, use the dos version
! */
! if(!seenBSD) goto done;
!
! /*
! * next, dig out disk label
! */
bp->b_blkno = dospartoff + LABELSECTOR;
bp->b_cylin = cyl;
bp->b_bcount = lp->d_secsize;
***************
*** 249,274 ****
/* if successful, locate disk label within block and validate */
if (biowait(bp)) {
! msg = "disk label I/O error";
goto done;
! } else for (dlp = (struct disklabel *)bp->b_un.b_addr;
dlp <= (struct disklabel *)(bp->b_un.b_addr+DEV_BSIZE-sizeof(*dlp));
dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
! if (msg == NULL)
! msg = "no disk label";
! } else if (dlp->d_npartitions > MAXPARTITIONS ||
! dkcksum(dlp) != 0)
! msg = "disk label corrupted";
! else {
! *lp = *dlp;
! msg = NULL;
! break;
}
}
!
! if (msg)
goto done;
/* obtain bad sector table if requested and present */
if (bdp && (lp->d_flags & D_BADSECT)) {
--- 316,345 ----
/* if successful, locate disk label within block and validate */
if (biowait(bp)) {
! printf("disk label I/O error\n");
goto done;
! /* leave us at least with the dos partitions */
! }
! for (dlp = (struct disklabel *)bp->b_un.b_addr;
dlp <= (struct disklabel *)(bp->b_un.b_addr+DEV_BSIZE-sizeof(*dlp));
dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
! continue;
}
+ if (dlp->d_npartitions > MAXPARTITIONS ||
+ dkcksum(dlp) != 0) {
+ printf("disk label corrupted\n");
+ goto done;
+ /* leave us at least with the dos partitions */
+ }
+ *lp = *dlp;
+ msg = NULL;
+ break;
}
! if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
! printf("No disklabel found\n");
goto done;
+ }
/* obtain bad sector table if requested and present */
if (bdp && (lp->d_flags & D_BADSECT)) {
--------------end of patch-----------