bsdlabel(8) could automatically fill many of disklabel's deprecated

fields, but user could specify some of those fields when edits disklabel
with `bsdlabel -e`. But without -A flag these fields might be
overwritten with default values from the virgin disklabel.
So, don't overwrite such fields if they are not zero. Also add checks
to prevent creating disklabel with less than DEFPARTITIONS and more
than MAXPARTITIONS partitions.

PR:		bin/162332
Tested by:	Eugene Grosbein
MFC after:	1 week

1 files changed, 35 insertions, 11 deletions

diff --git a/sbin/bsdlabel/bsdlabel.c b/sbin/bsdlabel/bsdlabel.c
index 83d5a4c..4f5a2c6 100644
--- a/sbin/bsdlabel/bsdlabel.c
+++ b/sbin/bsdlabel/bsdlabel.c
@@ -836,6 +836,11 @@ getasciilabel(FILE *f, struct disklabel *lp)
 				    "line %d: bad # of partitions\n", lineno);
 				lp->d_npartitions = MAXPARTITIONS;
 				errors++;
+			} else if (v < DEFPARTITIONS) {
+				fprintf(stderr,
+				    "line %d: bad # of partitions\n", lineno);
+				lp->d_npartitions = DEFPARTITIONS;
+				errors++;
 			} else
 				lp->d_npartitions = v;
 			continue;
@@ -1149,23 +1154,42 @@ checklabel(struct disklabel *lp)
 			errors++;
 		} else if (lp->d_bbsize % lp->d_secsize)
 			warnx("boot block size %% sector-size != 0");
-		if (lp->d_npartitions > MAXPARTITIONS)
+		if (lp->d_npartitions > MAXPARTITIONS) {
 			warnx("number of partitions (%lu) > MAXPARTITIONS (%d)",
 			    (u_long)lp->d_npartitions, MAXPARTITIONS);
+			errors++;
+		}
+		if (lp->d_npartitions < DEFPARTITIONS) {
+			warnx("number of partitions (%lu) < DEFPARTITIONS (%d)",
+			    (u_long)lp->d_npartitions, DEFPARTITIONS);
+			errors++;
+		}
 	} else {
 		struct disklabel *vl;
 
 		vl = getvirginlabel();
-		lp->d_secsize = vl->d_secsize;
-		lp->d_nsectors = vl->d_nsectors;
-		lp->d_ntracks = vl->d_ntracks;
-		lp->d_ncylinders = vl->d_ncylinders;
-		lp->d_rpm = vl->d_rpm;
-		lp->d_interleave = vl->d_interleave;
-		lp->d_secpercyl = vl->d_secpercyl;
-		lp->d_secperunit = vl->d_secperunit;
-		lp->d_bbsize = vl->d_bbsize;
-		lp->d_npartitions = vl->d_npartitions;
+		if (lp->d_secsize == 0)
+			lp->d_secsize = vl->d_secsize;
+		if (lp->d_nsectors == 0)
+			lp->d_nsectors = vl->d_nsectors;
+		if (lp->d_ntracks == 0)
+			lp->d_ntracks = vl->d_ntracks;
+		if (lp->d_ncylinders == 0)
+			lp->d_ncylinders = vl->d_ncylinders;
+		if (lp->d_rpm == 0)
+			lp->d_rpm = vl->d_rpm;
+		if (lp->d_interleave == 0)
+			lp->d_interleave = vl->d_interleave;
+		if (lp->d_secpercyl == 0)
+			lp->d_secpercyl = vl->d_secpercyl;
+		if (lp->d_secperunit == 0)
+			lp->d_secperunit = vl->d_secperunit;
+		if (lp->d_bbsize == 0)
+			lp->d_bbsize = vl->d_bbsize;
+		if (lp->d_npartitions == 0 ||
+		    lp->d_npartitions < DEFPARTITIONS ||
+		    lp->d_npartitions > MAXPARTITIONS)
+			lp->d_npartitions = vl->d_npartitions;
 	}