tests: Add a test for fd leaks on zombie objects

Until recently, if a client destroying a resource raced with the
server generating an event on that resource that delivered a file
descriptor, we would leak the fd.

This tests for a leaked fd from that race condition.
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Derek Foreman <derekf@osg.samsung.com>

Makefile.am

@@ -114,7 +114,8 @@ protocol/%-client-protocol-core.h : $(top_srcdir)/protocol/%.xml
 BUILT_SOURCES =					\
 	$(nodist_libwayland_server_la_SOURCES)	\
 	$(nodist_libwayland_client_la_SOURCES)	\
-	$(nodist_headers_test_SOURCES)
+	$(nodist_headers_test_SOURCES)		\
+	$(nodist_display_test_SOURCES)
 
 CLEANFILES = $(BUILT_SOURCES) doc/doxygen/doxygen_sqlite3.db
 DISTCLEANFILES = src/wayland-version.h
@@ -206,6 +207,10 @@ client_test_SOURCES = tests/client-test.c
 client_test_LDADD = libtest-runner.la
 display_test_SOURCES = tests/display-test.c
 display_test_LDADD = libtest-runner.la
+nodist_display_test_SOURCES =				\
+	protocol/tests-server-protocol.h		\
+	protocol/tests-client-protocol.h 		\
+	protocol/tests-protocol.c
 connection_test_SOURCES = tests/connection-test.c
 connection_test_LDADD = libtest-runner.la
 event_loop_test_SOURCES = tests/event-loop-test.c

protocol/tests.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="build_time_wayland_tests">
+
+  <copyright>
+    Copyright © 2017 Samsung Electronics Co., Ltd
+
+    Permission is hereby granted, free of charge, to any person
+    obtaining a copy of this software and associated documentation files
+    (the "Software"), to deal in the Software without restriction,
+    including without limitation the rights to use, copy, modify, merge,
+    publish, distribute, sublicense, and/or sell copies of the Software,
+    and to permit persons to whom the Software is furnished to do so,
+    subject to the following conditions:
+
+    The above copyright notice and this permission notice (including the
+    next paragraph) shall be included in all copies or substantial
+    portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+    NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+    BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+    ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+  </copyright>
+
+  <interface name="fd_passer" version="1">
+    <description summary="Sends an event with an fd">
+      A trivial interface for fd passing tests.
+    </description>
+
+    <request name="destroy" type="destructor"/>
+
+    <event name="pre_fd"/>
+
+    <event name="fd">
+      <description summary="passes a file descriptor"/>
+      <arg name="fd" type="fd" summary="file descriptor"/>
+    </event>
+  </interface>
+</protocol>

tests/display-test.c

@@ -47,6 +47,9 @@
 #include "test-runner.h"
 #include "test-compositor.h"
 
+#include "tests-server-protocol.h"
+#include "tests-client-protocol.h"
+
 struct display_destroy_listener {
 	struct wl_listener listener;
 	int done;
@@ -1066,3 +1069,102 @@ TEST(bind_fails_on_filtered_global)
 
 	display_destroy(d);
 }
+
+static void
+pre_fd(void *data, struct fd_passer *fdp)
+{
+	fd_passer_destroy(fdp);
+}
+
+static void
+fd(void *data, struct fd_passer *fdp, int32_t fd)
+{
+	/* We destroyed the resource before this event */
+	assert(false);
+}
+
+struct fd_passer_listener fd_passer_listener = {
+	pre_fd,
+	fd,
+};
+
+static void
+zombie_fd_handle_globals(void *data, struct wl_registry *registry,
+			 uint32_t id, const char *intf, uint32_t ver)
+{
+	struct fd_passer *fdp;
+
+	if (!strcmp(intf, "fd_passer")) {
+		fdp = wl_registry_bind(registry, id, &fd_passer_interface, 1);
+		fd_passer_add_listener(fdp, &fd_passer_listener, NULL);
+	}
+}
+
+static const struct wl_registry_listener zombie_fd_registry_listener = {
+	zombie_fd_handle_globals,
+	NULL
+};
+
+static void
+zombie_client(void *data)
+{
+	struct client *c = client_connect();
+	struct wl_registry *registry;
+
+	registry = wl_display_get_registry(c->wl_display);
+	wl_registry_add_listener(registry, &zombie_fd_registry_listener, NULL);
+
+	/* Gets the registry */
+	wl_display_roundtrip(c->wl_display);
+
+	/* push out the fd_passer bind */
+	wl_display_roundtrip(c->wl_display);
+
+	/* push out our fd_passer.destroy */
+	wl_display_roundtrip(c->wl_display);
+
+	wl_registry_destroy(registry);
+
+	client_disconnect_nocheck(c);
+}
+
+static void
+fd_passer_clobber(struct wl_client *client, struct wl_resource *res)
+{
+	wl_resource_destroy(res);
+}
+
+static const struct fd_passer_interface fdp_interface = {
+	fd_passer_clobber,
+};
+
+static void
+bind_fd_passer(struct wl_client *client, void *data,
+	       uint32_t vers, uint32_t id)
+{
+	struct wl_resource *res;
+
+	res = wl_resource_create(client, &fd_passer_interface, vers, id);
+	wl_resource_set_implementation(res, &fdp_interface, NULL, NULL);
+	assert(res);
+	fd_passer_send_pre_fd(res);
+	fd_passer_send_fd(res, fileno(stdin));
+}
+
+TEST(zombie_fd)
+{
+	struct display *d;
+	struct wl_global *g;
+
+	d = display_create();
+
+	g = wl_global_create(d->wl_display, &fd_passer_interface,
+			     1, d, bind_fd_passer);
+
+	client_create_noarg(d, zombie_client);
+	display_run(d);
+
+	wl_global_destroy(g);
+
+	display_destroy(d);
+}