From 5af15532cefecb5665736f30e00960c17700d1b0 Mon Sep 17 00:00:00 2001
From: Anoop C S <anoopcs@redhat.com>
Date: Fri, 10 Feb 2017 21:38:11 +0530
Subject: Avoid mutex lock wait in socket close failure

In case of absence to close a socket fd during an exit from
application we try to close the same by traversing the
socket_fds in swrap_destructor. But the early lock taken on
libc_symbol_binding_mutex inside the destructor blocks the
subsequent request for locking the same while loading
libc_close within swrap_close.

Also added a test case to verify this flaw in destructor.

Signed-off-by: Anoop C S <anoopcs@redhat.com>
Reviewed-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Michael Adam <obnox@samba.org>
---
 tests/CMakeLists.txt       |  3 ++-
 tests/test_close_failure.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 tests/test_close_failure.c

(limited to 'tests')

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 9292b40..c2bd799 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -35,7 +35,8 @@ set(SWRAP_TESTS
     test_echo_udp_send_recv
     test_echo_udp_sendmsg_recvmsg
     test_swrap_unit
-    test_max_sockets)
+    test_max_sockets
+    test_close_failure)
 
 if (HAVE_STRUCT_MSGHDR_MSG_CONTROL)
     set(SWRAP_TESTS ${SWRAP_TESTS} test_sendmsg_recvmsg_fd)
diff --git a/tests/test_close_failure.c b/tests/test_close_failure.c
new file mode 100644
index 0000000..0c9d6a7
--- /dev/null
+++ b/tests/test_close_failure.c
@@ -0,0 +1,50 @@
+#include "torture.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <cmocka.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+static int setup(void **state)
+{
+	torture_setup_socket_dir(state);
+
+	return 0;
+}
+
+static int teardown(void **state)
+{
+	torture_teardown_socket_dir(state);
+
+	return 0;
+}
+
+static void test_close_failure(void **state)
+{
+	int s;
+	int rc;
+
+	(void) state; /* unused */
+	(void) s; /*set but not used */
+
+	s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+
+	assert_int_not_equal(rc, -1);
+
+	/* Do not close the socket here so that destructor
+	 * handles it and no hang should be observed.*/
+}
+
+int main(void) {
+	int rc;
+
+	const struct CMUnitTest close_failure_tests[] = {
+		cmocka_unit_test_setup_teardown(test_close_failure,
+						setup, teardown),
+	};
+
+	rc = cmocka_run_group_tests(close_failure_tests, NULL, NULL);
+
+	return rc;
+}
-- 
cgit