From 2c19171bc113241ee7c630c9ab46d2e95c18c942 Mon Sep 17 00:00:00 2001
From: "Tim J. Robbins" <tjr@FreeBSD.org>
Date: Mon, 13 Jan 2003 02:58:18 +0000
Subject: [PATCH] Lock the stream before calling __sfileno() to retrieve the
 file descriptor. 1003.1-2001 requires that fileno() behave as if it locks the
 stream.

---
 lib/libc/stdio/fileno.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/lib/libc/stdio/fileno.c b/lib/libc/stdio/fileno.c
index 97f25e37a33..d7bf93deeaa 100644
--- a/lib/libc/stdio/fileno.c
+++ b/lib/libc/stdio/fileno.c
@@ -40,7 +40,10 @@ static char sccsid[] = "@(#)fileno.c	8.1 (Berkeley) 6/4/93";
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include "namespace.h"
 #include <stdio.h>
+#include "un-namespace.h"
+#include "libc_private.h"
 
 /*
  * fileno has traditionally been a macro in <stdio.h>.  That is
@@ -51,6 +54,11 @@ __FBSDID("$FreeBSD$");
 int
 fileno(FILE *fp)
 {
-	/* ??? - Should probably use atomic_read. */
-	return (__sfileno(fp));
+	int fd;
+
+	FLOCKFILE(fp);
+	fd = __sfileno(fp);
+	FUNLOCKFILE(fp);
+
+	return (fd);
 }