tests: Fix signalling race condition in TPM tests

This patch fixes a race condition and test failure where the main process
waits for the signal of a thread but the thread already sent that signal
via a condition. Since these signals are non-sticky, we need to introduce a
separate variable to make this signal sticky.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

tests/tpm-crb-test.c

@@ -151,6 +151,7 @@ int main(int argc, char **argv)
     test.addr->u.q_unix.path = g_build_filename(tmp_path, "sock", NULL);
     g_mutex_init(&test.data_mutex);
     g_cond_init(&test.data_cond);
+    test.data_cond_signal = false;
 
     thread = g_thread_new(NULL, tpm_emu_ctrl_thread, &test);
     tpm_emu_test_wait_cond(&test);

tests/tpm-emu.c

@@ -23,9 +23,14 @@ void tpm_emu_test_wait_cond(TestState *s)
     gint64 end_time = g_get_monotonic_time() + 5 * G_TIME_SPAN_SECOND;
 
     g_mutex_lock(&s->data_mutex);
-    if (!g_cond_wait_until(&s->data_cond, &s->data_mutex, end_time)) {
+
+    if (!s->data_cond_signal &&
+        !g_cond_wait_until(&s->data_cond, &s->data_mutex, end_time)) {
         g_assert_not_reached();
     }
+
+    s->data_cond_signal = false;
+
     g_mutex_unlock(&s->data_mutex);
 }
 
@@ -72,6 +77,10 @@ void *tpm_emu_ctrl_thread(void *data)
     QIOChannel *ioc;
 
     qio_channel_socket_listen_sync(lioc, s->addr, &error_abort);
+
+    g_mutex_lock(&s->data_mutex);
+    s->data_cond_signal = true;
+    g_mutex_unlock(&s->data_mutex);
     g_cond_signal(&s->data_cond);
 
     qio_channel_wait(QIO_CHANNEL(lioc), G_IO_IN);

tests/tpm-emu.h

@@ -26,6 +26,7 @@ struct tpm_hdr {
 typedef struct TestState {
     GMutex data_mutex;
     GCond data_cond;
+    bool data_cond_signal;
     SocketAddress *addr;
     QIOChannel *tpm_ioc;
     GThread *emu_tpm_thread;

tests/tpm-tis-test.c

@@ -446,6 +446,7 @@ int main(int argc, char **argv)
     test.addr->u.q_unix.path = g_build_filename(tmp_path, "sock", NULL);
     g_mutex_init(&test.data_mutex);
     g_cond_init(&test.data_cond);
+    test.data_cond_signal = false;
 
     thread = g_thread_new(NULL, tpm_emu_ctrl_thread, &test);
     tpm_emu_test_wait_cond(&test);