tests/libqtest.c: Delete possible stale unix sockets

Occasionally if a test crashes or is interrupted by the user
at the wrong moment it could leave behind a stale UNIX
socket in /tmp/. This will then cause a subsequent test
run to fail spuriously with
 tests/libqtest.c:70:init_socket: assertion failed (ret != -1): (-1 != -1)
if it happens to reuse the same PID.

Defend against this by deleting any stray stale socket before
trying to open the new ones for this test.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1490963801-27870-1-git-send-email-peter.maydell@linaro.org

1 files changed, 8 insertions, 0 deletions

diff --git a/tests/libqtest.c b/tests/libqtest.c
index a5c3d2bf48..99b1195355 100644
--- a/tests/libqtest.c
+++ b/tests/libqtest.c
@@ -167,6 +167,14 @@ QTestState *qtest_init_without_qmp_handshake(const char *extra_args)
     socket_path = g_strdup_printf("/tmp/qtest-%d.sock", getpid());
     qmp_socket_path = g_strdup_printf("/tmp/qtest-%d.qmp", getpid());
 
+    /* It's possible that if an earlier test run crashed it might
+     * have left a stale unix socket lying around. Delete any
+     * stale old socket to avoid spurious test failures with
+     * tests/libqtest.c:70:init_socket: assertion failed (ret != -1): (-1 != -1)
+     */
+    unlink(socket_path);
+    unlink(qmp_socket_path);
+
     sock = init_socket(socket_path);
     qmpsock = init_socket(qmp_socket_path);