From 648cb40472db57173670f806fe29dfd6a6330b03 Mon Sep 17 00:00:00 2001
From: deraadt <deraadt@openbsd.org>
Date: Sun, 6 Apr 1997 06:13:03 +0000
Subject: [PATCH] support cd9660 disklabel spoofing; also fix block offset
 confusion

---
 sys/arch/mvme68k/mvme68k/disksubr.c | 32 +++++++++++++++++------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/sys/arch/mvme68k/mvme68k/disksubr.c b/sys/arch/mvme68k/mvme68k/disksubr.c
index c8b61973d79..6d8f6accb10 100644
--- a/sys/arch/mvme68k/mvme68k/disksubr.c
+++ b/sys/arch/mvme68k/mvme68k/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.11 1997/02/15 15:22:08 rahnds Exp $ */
+/*	$OpenBSD: disksubr.c,v 1.12 1997/04/06 06:13:03 deraadt Exp $ */
 
 /*
  * Copyright (c) 1995 Dale Rahn.
@@ -136,6 +136,10 @@ readdisklabel(dev, strat, lp, clp)
 	brelse(bp);
 
 	if (msg) {
+#if defined(CD9660)
+		if (iso_disklabelspoof(dev, strat, lp) == 0)
+			msg = NULL;
+#endif
 		return (msg); 
 	}
 	cputobsdlabel(lp, clp);
@@ -297,16 +301,17 @@ bounds_check_with_label(bp, lp, wlabel)
 	struct disklabel *lp;
 	int wlabel;
 {
+#define blockpersec(count, lp) ((count) * (((lp)->d_secsize) / DEV_BSIZE))
 	struct partition *p = lp->d_partitions + DISKPART(bp->b_dev);
-	int labelsect = lp->d_partitions[0].p_offset;
-	int maxsz = p->p_size;
-	int sz = (bp->b_bcount + DEV_BSIZE - 1) >> DEV_BSHIFT;
+	int labelsect = blockpersec(lp->d_partitions[0].p_offset, lp) +
+	    LABELSECTOR;
+	int sz = howmany(bp->b_bcount, DEV_BSIZE);
 
 	/* overwriting disk label ? */
 	/* XXX should also protect bootstrap in first 8K */
-	if (bp->b_blkno + p->p_offset <= LABELSECTOR + labelsect &&
+	if (bp->b_blkno + p->p_offset <= labelsect &&
 #if LABELSECTOR != 0
-	    bp->b_blkno + p->p_offset + sz > LABELSECTOR + labelsect &&
+	    bp->b_blkno + p->p_offset + sz > labelsect &&
 #endif
 	    (bp->b_flags & B_READ) == 0 && wlabel == 0) {
 		bp->b_error = EROFS;
@@ -314,23 +319,24 @@ bounds_check_with_label(bp, lp, wlabel)
 	}
 
 	/* beyond partition? */
-	if (bp->b_blkno < 0 || bp->b_blkno + sz > maxsz) {
-		/* if exactly at end of disk, return an EOF */
-		if (bp->b_blkno == maxsz) {
+	if (bp->b_blkno + sz > blockpersec(p->p_size, lp)) {
+		sz = blockpersec(p->p_size, lp) - bp->b_blkno;
+		if (sz == 0) {
+			/* if exactly at end of disk, return an EOF */
 			bp->b_resid = bp->b_bcount;
 			return(0);
 		}
-		/* or truncate if part of it fits */
-		sz = maxsz - bp->b_blkno;
-		if (sz <= 0) {
+		if (sz < 0) {
 			bp->b_error = EINVAL;
 			goto bad;
 		}
+		/* or truncate if part of it fits */
 		bp->b_bcount = sz << DEV_BSHIFT;
 	}
 
 	/* calculate cylinder for disksort to order transfers with */
-	bp->b_cylin = (bp->b_blkno + p->p_offset) / lp->d_secpercyl;
+	bp->b_cylin = (bp->b_blkno + blockpersec(p->p_offset, lp)) /
+	    lp->d_secpercyl;
 	return(1);
 
 bad:
-- 
2.20.1