[src/trunk]: src/tests/include/sys Avoid undefined behavior in an ATF test: t...

[kamil <kamil%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/2d97d3b1d2bf
branches:  trunk
changeset: 991676:2d97d3b1d2bf
user:      kamil <kamil%NetBSD.org@localhost>
date:      Wed Jul 25 21:51:32 2018 +0000

description:
Avoid undefined behavior in an ATF test: t_types

Replace UB with implementation defined logic to check whether ssize_t can
wrap to a negative number.

t_types.c:63:7, signed integer overflow: 9223372036854775807 + 1 cannot be represented in type 'long int'

Detected with micro-UBSan in the user mode.

diffstat:

 tests/include/sys/t_types.c |  6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diffs (27 lines):

diff -r 5015aafa6297 -r 2d97d3b1d2bf tests/include/sys/t_types.c
--- a/tests/include/sys/t_types.c       Wed Jul 25 20:05:35 2018 +0000
+++ b/tests/include/sys/t_types.c       Wed Jul 25 21:51:32 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: t_types.c,v 1.4 2012/03/18 07:14:08 jruoho Exp $ */
+/*     $NetBSD: t_types.c,v 1.5 2018/07/25 21:51:32 kamil Exp $ */
 
 /*-
  * Copyright (c) 2011 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: t_types.c,v 1.4 2012/03/18 07:14:08 jruoho Exp $");
+__RCSID("$NetBSD: t_types.c,v 1.5 2018/07/25 21:51:32 kamil Exp $");
 
 #include <sys/types.h>
 
@@ -60,7 +60,7 @@
        size = SSIZE_MAX;
        ATF_REQUIRE(size > 0);
 
-       size = size + 1;
+       size = (ssize_t)((size_t)size + 1);
        ATF_REQUIRE(size < 0);
 
        /*