Handle snprintf() returning < 0 (not just -1)

MFC after:	2 weeks

3 files changed, 7 insertions, 3 deletions

diff --git a/sbin/newfs/mkfs.c b/sbin/newfs/mkfs.c
index 84f0d9b..4772ae9 100644
--- a/sbin/newfs/mkfs.c
+++ b/sbin/newfs/mkfs.c
@@ -650,8 +650,8 @@ next:
 		j = snprintf(tmpbuf, sizeof(tmpbuf), " %ld%s",
 		    fsbtodb(&sblock, cgsblock(&sblock, cylno)),
 		    cylno < (sblock.fs_ncg-1) ? "," : "" );
-		if (j == -1)
-			j = 0;
+		if (j < 0)
+			tmpbuf[j = 0] = '\0';
 		if (i + j >= width) {
 			printf("\n");
 			i = 0;
diff --git a/sbin/ping6/ping6.c b/sbin/ping6/ping6.c
index 83f6682..790e921 100644
--- a/sbin/ping6/ping6.c
+++ b/sbin/ping6/ping6.c
@@ -1353,7 +1353,7 @@ dnsdecode(sp, ep, base, buf, bufsiz)
 			while (i-- > 0 && cp < ep) {
 				l = snprintf(cresult, sizeof(cresult),
 				    isprint(*cp) ? "%c" : "\\%03o", *cp & 0xff);
-				if (l == -1 || l >= sizeof(cresult))
+				if (l < 0 || l >= sizeof(cresult))
 					return NULL;
 				if (strlcat(buf, cresult, bufsiz) >= bufsiz)
 					return NULL;	/*result overrun*/
diff --git a/sbin/route/route.c b/sbin/route/route.c
index 64a2e60..dd23bc1 100644
--- a/sbin/route/route.c
+++ b/sbin/route/route.c
@@ -410,6 +410,8 @@ routename(sa)
 		while (++s < slim && cp < cpe) /* start with sa->sa_data */
 			if ((n = snprintf(cp, cpe - cp, " %x", *s)) > 0)
 				cp += n;
+			else
+				*cp = '\0';
 		break;
 	    }
 	}
@@ -546,6 +548,8 @@ netname(sa)
 		while (s < slim && cp < cpe)
 			if ((n = snprintf(cp, cpe - cp, " %x", *s++)) > 0)
 				cp += n;
+			else
+				*cp = '\0';
 		break;
 	    }
 	}