display: Add checks on GetActiveConfig API

This change adds null pointer checks on the GetActiveConfig API.

Change-Id: Ic61507ab9fe083f85a7708e262ecdf7714cf9087
CRs-Fixed: 2784749

services/config/src/client_impl.cpp

@@ -140,6 +140,10 @@ int ClientImpl::GetConfigCount(DisplayType dpy, uint32_t *count) {
 }
 
 int ClientImpl::GetActiveConfig(DisplayType dpy, uint32_t *config) {
+  if (!config) {
+    return -EINVAL;
+  }
+
   ByteStream input_params;
   input_params.setToExternal(reinterpret_cast<uint8_t*>(&dpy), sizeof(DisplayType));
   const uint32_t *output;
@@ -150,11 +154,15 @@ int ClientImpl::GetActiveConfig(DisplayType dpy, uint32_t *config) {
     output_params = params;
   };
 
+  if (display_config_) {
     display_config_->perform(client_handle_, kGetActiveConfig, input_params, {}, hidl_cb);
+  }
 
+  if (!error) {
     const uint8_t *data = output_params.data();
     output = reinterpret_cast<const uint32_t*>(data);
     *config = *output;
+  }
 
   return error;
 }

services/config/src/device_impl.cpp

@@ -61,6 +61,7 @@ int DeviceImpl::CreateInstance(ClientContext *intf) {
 Return<void> DeviceImpl::registerClient(const hidl_string &client_name,
                                         const sp<IDisplayConfigCallback>& callback,
                                         registerClient_cb _hidl_cb) {
+  ALOGI("Register client:%s", client_name.c_str());
   int32_t error = 0;
   std::string client_name_str = client_name.c_str();
   if (client_name_str.empty()) {