From 31d396587e83d6820aa1de3a2084f68d39d9fdaf Mon Sep 17 00:00:00 2001
From: Jilles Tjoelker <jilles@FreeBSD.org>
Date: Sun, 13 Jan 2013 19:26:33 +0000
Subject: [PATCH] sh: Fix crash when parsing '{ } &'.

MFC after:	1 week
---
 bin/sh/parser.c                                | 4 ++--
 tools/regression/bin/sh/parser/empty-braces1.0 | 7 +++++++
 2 files changed, 9 insertions(+), 2 deletions(-)
 create mode 100644 tools/regression/bin/sh/parser/empty-braces1.0

diff --git a/bin/sh/parser.c b/bin/sh/parser.c
index a19ca3127bd3..665b53ff5aae 100644
--- a/bin/sh/parser.c
+++ b/bin/sh/parser.c
@@ -240,9 +240,9 @@ list(int nlflag, int erflag)
 		n2 = andor();
 		tok = readtoken();
 		if (tok == TBACKGND) {
-			if (n2->type == NPIPE) {
+			if (n2 != NULL && n2->type == NPIPE) {
 				n2->npipe.backgnd = 1;
-			} else if (n2->type == NREDIR) {
+			} else if (n2 != NULL && n2->type == NREDIR) {
 				n2->type = NBACKGND;
 			} else {
 				n3 = (union node *)stalloc(sizeof (struct nredir));
diff --git a/tools/regression/bin/sh/parser/empty-braces1.0 b/tools/regression/bin/sh/parser/empty-braces1.0
new file mode 100644
index 000000000000..5ab443c48d8a
--- /dev/null
+++ b/tools/regression/bin/sh/parser/empty-braces1.0
@@ -0,0 +1,7 @@
+# $FreeBSD$
+
+# Unfortunately, some scripts depend on the extension of allowing an empty
+# pair of braces.
+
+{ } &
+wait $!