bin/51250: A '$' is printed for blank lines when invoked with -se

[venture37%geeklan.co.uk@localhost]

>Number:         51250
>Category:       bin
>Synopsis:       A '$' is printed for blank lines when invoked with -se
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jun 16 00:25:00 +0000 2016
>Originator:     Sevan Janiyan
>Release:        Netbsd-head
>Organization:
Venture 37 Ltd
>Environment:
NetBSD 7.99.26 NetBSD 7.99.26 (GENERIC) #0: Sat Apr  2 19:23:46 UTC 2016 /usr/obj/sys/arch/amd64/compile/GENERIC amd64
>Description:
When 'cat -se' is used, a '$' is not printed for blank lines
>How-To-Repeat:
invoke cat with -se on a file containing empty lines. observe missing $ on those lines.
>Fix:
Obtained from OpenBSD r1.13 of src/bin/cat/cat.c

Index: cat.c
===================================================================
RCS file: /cvsroot/src/bin/cat/cat.c,v
retrieving revision 1.55
diff -u -p -u -r1.55 cat.c
--- cat.c	25 Jul 2015 16:17:01 -0000	1.55
+++ cat.c	3 Jun 2016 01:17:35 -0000
@@ -174,18 +174,16 @@ cook_buf(FILE *fp)
 	line = gobble = 0;
 	for (prev = '\n'; (ch = getc(fp)) != EOF; prev = ch) {
 		if (prev == '\n') {
-			if (ch == '\n') {
-				if (sflag) {
-					if (!gobble && nflag && !bflag)
-						(void)fprintf(stdout,
-							"%6d\t\n", ++line);
-					else if (!gobble && putchar(ch) == EOF)
-						break;
+			if (sflag) {
+				if (ch == '\n') {
+					if (gobble)
+						continue;
 					gobble = 1;
-					continue;
+				} else
+					gobble = 0;
 				}
 				if (nflag) {
-					if (!bflag) {
+					if (!bflag || ch != '\n') {
 						(void)fprintf(stdout,
 						    "%6d\t", ++line);
 						if (ferror(stdout))
@@ -197,13 +195,7 @@ cook_buf(FILE *fp)
 							break;
 					}
 				}
-			} else if (nflag) {
-				(void)fprintf(stdout, "%6d\t", ++line);
-				if (ferror(stdout))
-					break;
 			}
-		}
-		gobble = 0;
 		if (ch == '\n') {
 			if (eflag)
 				if (putchar('$') == EOF)