Fix a 37 year old bug introduced by Bill Joy on August 24, 1977

that was already present in the 1BSD release on March 9, 1978
by merging Keith Bostic's 22 year old fix from 4.4BSD (not kidding).

Original CSRG SCCS commit message:

  ^As 00009/00006/00145
  ^Ad D 5.7 92/03/04 14:35:42 bostic 9 8
  ^Ac can't use freopen; example is "date | head file1 /dev/stdin"

ok deraadt@ tedu@, also checked by Martin <Natano dot net>

1 files changed, 7 insertions, 5 deletions

diff --git a/usr.bin/head/head.c b/usr.bin/head/head.c
index d48bd682a8c..3e94eb5761b 100644
--- a/usr.bin/head/head.c
+++ b/usr.bin/head/head.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: head.c,v 1.17 2014/10/07 19:38:57 tedu Exp $	*/
+/*	$OpenBSD: head.c,v 1.18 2014/10/08 08:31:53 schwarze Exp $	*/
 
 /*
  * Copyright (c) 1980, 1987 Regents of the University of California.
@@ -48,6 +48,7 @@ static void usage(void);
 int
 main(int argc, char *argv[])
 {
+	FILE	*fp;
 	long 	cnt;
 	int	ch, firsttime;
 	long	linecnt = 10;
@@ -81,13 +82,13 @@ main(int argc, char *argv[])
 			errx(1, "line count %s: %s", errstr, p);
 	}
 
-	/* setlinebuf(stdout); */
 	for (firsttime = 1; ; firsttime = 0) {
 		if (!*argv) {
 			if (!firsttime)
 				exit(status);
+			fp = stdin;
 		} else {
-			if (!freopen(*argv, "r", stdin)) {
+			if ((fp = fopen(*argv, "r")) == NULL) {
 				warn("%s", *argv++);
 				status = 1;
 				continue;
@@ -99,10 +100,11 @@ main(int argc, char *argv[])
 			}
 			++argv;
 		}
-		for (cnt = linecnt; cnt && !feof(stdin); --cnt)
-			while ((ch = getchar()) != EOF)
+		for (cnt = linecnt; cnt && !feof(fp); --cnt)
+			while ((ch = getc(fp)) != EOF)
 				if (putchar(ch) == '\n')
 					break;
+		fclose(fp);
 	}
 	/*NOTREACHED*/
 }