fortify: Fix spurious warning with realpath

The length and object size arguments were swapped around for realpath.
Also add a smoke test so that any changes in this area get caught in
future.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit 2bbd07c715275eb6c616988925738a0517180d57)

1 files changed, 37 insertions, 0 deletions

diff --git a/debug/tst-realpath-chk.c b/debug/tst-realpath-chk.c
new file mode 100644
index 0000000000..a8fcb327c4
--- /dev/null
+++ b/debug/tst-realpath-chk.c
@@ -0,0 +1,37 @@
+/* Smoke test to verify that realpath does not cause spurious warnings.
+   Copyright The GNU Toolchain Authors.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <limits.h>
+#include <stdlib.h>
+
+#include <support/check.h>
+#include <support/support.h>
+
+static int
+do_test (void)
+{
+#ifdef PATH_MAX
+  char buf[PATH_MAX + 1];
+  char *res = realpath (".", buf);
+  TEST_VERIFY (res == buf);
+#endif
+
+  return 0;
+}
+
+#include <support/test-driver.c>