From b6dd340d3c5e64e71932c3da8bfd9bca6bc760d3 Mon Sep 17 00:00:00 2001
From: kre <kre@NetBSD.org>
Date: Tue, 16 Nov 2021 16:57:15 +0000
Subject: [PATCH] Make pwd (both /bin/pwd and the /bin/sh built-in version)
 check for write errors on stdout, and indicate an error if that happens.

---
 bin/pwd/pwd.c |  8 ++++++--
 bin/sh/cd.c   | 11 +++++++++--
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/bin/pwd/pwd.c b/bin/pwd/pwd.c
index 27888ebf7eba..2ec3a804a050 100644
--- a/bin/pwd/pwd.c
+++ b/bin/pwd/pwd.c
@@ -1,4 +1,4 @@
-/* $NetBSD: pwd.c,v 1.22 2011/08/29 14:51:19 joerg Exp $ */
+/* $NetBSD: pwd.c,v 1.23 2021/11/16 16:57:15 kre Exp $ */
 
 /*
  * Copyright (c) 1991, 1993, 1994
@@ -39,7 +39,7 @@ __COPYRIGHT("@(#) Copyright (c) 1991, 1993, 1994\
 #if 0
 static char sccsid[] = "@(#)pwd.c	8.3 (Berkeley) 4/1/94";
 #else
-__RCSID("$NetBSD: pwd.c,v 1.22 2011/08/29 14:51:19 joerg Exp $");
+__RCSID("$NetBSD: pwd.c,v 1.23 2021/11/16 16:57:15 kre Exp $");
 #endif
 #endif /* not lint */
 
@@ -107,6 +107,10 @@ main(int argc, char *argv[])
 
 	(void)printf("%s\n", p);
 
+	(void)fflush(stdout);
+	if (ferror(stdout))
+		err(EXIT_FAILURE, "stdout");
+
 	exit(EXIT_SUCCESS);
 	/* NOTREACHED */
 }
diff --git a/bin/sh/cd.c b/bin/sh/cd.c
index 178c44f4f7e3..66a9c5d009d2 100644
--- a/bin/sh/cd.c
+++ b/bin/sh/cd.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: cd.c,v 1.51 2021/10/31 02:12:01 kre Exp $	*/
+/*	$NetBSD: cd.c,v 1.52 2021/11/16 16:57:15 kre Exp $	*/
 
 /*-
  * Copyright (c) 1991, 1993
@@ -37,7 +37,7 @@
 #if 0
 static char sccsid[] = "@(#)cd.c	8.2 (Berkeley) 5/4/95";
 #else
-__RCSID("$NetBSD: cd.c,v 1.51 2021/10/31 02:12:01 kre Exp $");
+__RCSID("$NetBSD: cd.c,v 1.52 2021/11/16 16:57:15 kre Exp $");
 #endif
 #endif /* not lint */
 
@@ -364,8 +364,15 @@ pwdcmd(int argc, char **argv)
 		if (curdir == NULL)
 			error("Unable to find current directory");
 	}
+
+	flushout(out1);		/* make sure buffer is empty */
+	clr_err(out1);		/* and forget any earlier errors */
 	out1str(curdir);
 	out1c('\n');
+	flushout(out1);
+	if (io_err(out1))
+		error("stdout: %s", strerror(errno));
+
 	return 0;
 }