From cf3258890d0b34ff34a429ee3c008b66f15af5e2 Mon Sep 17 00:00:00 2001
From: christos <christos@NetBSD.org>
Date: Thu, 3 Aug 2006 22:51:05 +0000
Subject: [PATCH] PR/34129: Andreas Gustafsson: Nonblocking write to pty can
 return 0 If we cannot write on the slave side, always return EWOULDBLOCK in
 the non-blocking case, because we don't know that the buffer we started
 writing is actually in a system call boundary.

---
 sys/kern/tty.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index b5c08cfe436e..ca2fea9f4c58 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: tty.c,v 1.186 2006/07/23 22:06:11 ad Exp $	*/
+/*	$NetBSD: tty.c,v 1.187 2006/08/03 22:51:05 christos Exp $	*/
 
 /*-
  * Copyright (c) 1982, 1986, 1990, 1991, 1993
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tty.c,v 1.186 2006/07/23 22:06:11 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tty.c,v 1.187 2006/08/03 22:51:05 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -2100,7 +2100,7 @@ ttwrite(struct tty *tp, struct uio *uio, int flag)
 	if (flag & IO_NDELAY) {
 		TTY_UNLOCK(tp);
 		splx(s);
-		error = (uio->uio_resid == cnt) ? EWOULDBLOCK : 0;
+		error = EWOULDBLOCK;
 		goto out;
 	}
 	SET(tp->t_state, TS_ASLEEP);