pthreadpool: Add test for pthread_create failure

This is implemented using cmocka and the __wrap override for
pthread_create.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13170

Signed-off-by: Christof Schmitt <cs@samba.org
Reviewed-by: Andreas Schneider <asn@samba.org>

Autobuild-User(master): Christof Schmitt <cs@samba.org>
Autobuild-Date(master): Fri Dec  8 13:54:20 CET 2017 on sn-devel-144

(cherry picked from commit 8cdb3995caf7a21d0c27a56a0bf0c1efd5b491e4)

2 files changed, 183 insertions, 0 deletions

diff --git a/lib/pthreadpool/tests_cmocka.c b/lib/pthreadpool/tests_cmocka.c
new file mode 100644
index 00000000000..75a935fa42c
--- /dev/null
+++ b/lib/pthreadpool/tests_cmocka.c
@@ -0,0 +1,176 @@
+/*
+ * Unix SMB/CIFS implementation.
+ * cmocka tests for thread pool implementation
+ * Copyright (C) Christof Schmitt 2017
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <errno.h>
+#include <pthread.h>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <talloc.h>
+#include <tevent.h>
+#include <pthreadpool_tevent.h>
+
+#include <cmocka.h>
+
+struct pthreadpool_tevent_test {
+	struct tevent_context *ev;
+	struct pthreadpool_tevent *pool;
+};
+
+static int setup_pthreadpool_tevent(void **state)
+{
+	struct pthreadpool_tevent_test *t;
+	int ret;
+
+	t = talloc(NULL, struct pthreadpool_tevent_test);
+	assert_non_null(t);
+
+	t->ev = tevent_context_init(t);
+	assert_non_null(t->ev);
+
+	ret = pthreadpool_tevent_init(t->ev, 0, &t->pool);
+	assert_return_code(ret, 0);
+
+	*state = t;
+
+	return 0;
+}
+
+static int teardown_pthreadpool_tevent(void **state)
+{
+	struct pthreadpool_tevent_test *t = *state;
+
+	TALLOC_FREE(t);
+
+	return 0;
+}
+
+int __wrap_pthread_create(pthread_t *thread, const pthread_attr_t *attr,
+			  void *(*start_routine) (void *), void *arg);
+int __real_pthread_create(pthread_t *thread, const pthread_attr_t *attr,
+			  void *(*start_routine) (void *),  void *arg);
+
+int __wrap_pthread_create(pthread_t *thread, const pthread_attr_t *attr,
+			  void *(*start_routine) (void *), void *arg)
+{
+	int error;
+
+	error = mock_type(int);
+	if (error != 0) {
+		return error;
+	}
+
+	return __real_pthread_create(thread, attr, start_routine, arg);
+}
+
+static void test_job_threadid(void *ptr)
+{
+	pthread_t *threadid = ptr;
+
+	*threadid = pthread_self();
+}
+
+static int test_create_do(struct tevent_context *ev,
+			  struct pthreadpool_tevent *pool,
+			  bool *in_main_thread)
+{
+	struct tevent_req *req;
+	pthread_t main_thread, worker_thread;
+	bool ok;
+	int ret;
+
+	main_thread = pthread_self();
+
+	req = pthreadpool_tevent_job_send(
+		ev, ev, pool, test_job_threadid, &worker_thread);
+	if (req == NULL) {
+		fprintf(stderr, "pthreadpool_tevent_job_send failed\n");
+		TALLOC_FREE(ev);
+		return ENOMEM;
+	}
+
+	ok = tevent_req_poll(req, ev);
+	if (!ok) {
+		ret = errno;
+		fprintf(stderr, "tevent_req_poll failed: %s\n",
+			strerror(ret));
+		TALLOC_FREE(ev);
+		return ret;
+	}
+
+
+	ret = pthreadpool_tevent_job_recv(req);
+	TALLOC_FREE(req);
+	if (ret != 0) {
+		fprintf(stderr, "tevent_req_recv failed: %s\n",
+			strerror(ret));
+		TALLOC_FREE(ev);
+		return ret;
+	}
+	*in_main_thread = pthread_equal(worker_thread, main_thread);
+
+	return 0;
+}
+
+static void test_create(void **state)
+{
+	struct pthreadpool_tevent_test *t = *state;
+	bool in_main_thread;
+	int ret;
+
+	/*
+	 * When pthreadpool cannot create the first worker thread,
+	 * this job will run in the sync fallback in the main thread.
+	 */
+	will_return(__wrap_pthread_create, EAGAIN);
+	ret = test_create_do(t->ev, t->pool, &in_main_thread);
+	assert_return_code(ret, 0);
+	assert_true(in_main_thread);
+
+	/*
+	 * When a thread can be created, the job will run in the worker thread.
+	 */
+	will_return(__wrap_pthread_create, 0);
+	ret = test_create_do(t->ev, t->pool, &in_main_thread);
+	assert_return_code(ret, 0);
+	assert_false(in_main_thread);
+
+	/*
+	 * Workerthread will still be active for a second; immediately
+	 * running another job will also use the worker thread, even
+	 * if a new thread cannot be created.
+	 */
+	ret = test_create_do(t->ev, t->pool, &in_main_thread);
+	assert_return_code(ret, 0);
+	assert_false(in_main_thread);
+}
+
+int main(int argc, char **argv)
+{
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test_setup_teardown(test_create,
+						setup_pthreadpool_tevent,
+						teardown_pthreadpool_tevent),
+	};
+
+	cmocka_set_message_output(CM_OUTPUT_SUBUNIT);
+
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}
diff --git a/lib/pthreadpool/wscript_build b/lib/pthreadpool/wscript_build
index d5304635915..57df25548b1 100644
--- a/lib/pthreadpool/wscript_build
+++ b/lib/pthreadpool/wscript_build
@@ -21,3 +21,10 @@ bld.SAMBA_BINARY('pthreadpooltest',
                   deps='PTHREADPOOL',
                   enabled=bld.env.WITH_PTHREADPOOL,
                   install=False)
+
+bld.SAMBA_BINARY('pthreadpooltest_cmocka',
+                  source='tests_cmocka.c',
+                  deps='PTHREADPOOL cmocka',
+                  ldflags='-Wl,--wrap=pthread_create',
+                  enabled=bld.env.WITH_PTHREADPOOL and bld.env['HAVE_LDWRAP'],
+                  install=False)