Add microdroid-specialized KeyMint service

KeyMint in microdroid will initially be a specialized version of the
software KeyMint reference implementation. Begin this specialization by
removing the services that aren't needed within VMs.

Bug: 190578423
Test: atest MicrodroidHostTestCases
Change-Id: I6eee95944ccc555656868dad193f29b83ebf46a4
diff --git a/microdroid/keymint/service.cpp b/microdroid/keymint/service.cpp
new file mode 100644
index 0000000..d2b75a1
--- /dev/null
+++ b/microdroid/keymint/service.cpp
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2021, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "android.hardware.security.keymint-service"
+
+#include <AndroidKeyMintDevice.h>
+#include <android-base/logging.h>
+#include <android/binder_manager.h>
+#include <android/binder_process.h>
+#include <keymaster/soft_keymaster_logger.h>
+
+using aidl::android::hardware::security::keymint::AndroidKeyMintDevice;
+using aidl::android::hardware::security::keymint::SecurityLevel;
+
+template <typename T, class... Args>
+std::shared_ptr<T> addService(Args&&... args) {
+    std::shared_ptr<T> ser = ndk::SharedRefBase::make<T>(std::forward<Args>(args)...);
+    auto instanceName = std::string(T::descriptor) + "/default";
+    LOG(INFO) << "adding keymint service instance: " << instanceName;
+    binder_status_t status =
+            AServiceManager_addService(ser->asBinder().get(), instanceName.c_str());
+    CHECK(status == STATUS_OK);
+    return ser;
+}
+
+int main() {
+    // Zero threads seems like a useless pool, but below we'll join this thread to it, increasing
+    // the pool size to 1.
+    ABinderProcess_setThreadPoolMaxThreadCount(0);
+    // Add Keymint Service
+    std::shared_ptr<AndroidKeyMintDevice> keyMint =
+            addService<AndroidKeyMintDevice>(SecurityLevel::SOFTWARE);
+
+    // VMs cannot implement the Secure Clock Service
+    // addService<AndroidSecureClock>(keyMint);
+
+    // VMs don't need to implement the Shared Secret Service as the host
+    // facilities the establishment of the shared secret.
+    // addService<AndroidSharedSecret>(keyMint);
+
+    // VMs don't implement the Remotely Provisioned Component Service as the
+    // host facilities provisioning.
+    // addService<AndroidRemotelyProvisionedComponentDevice>(keyMint);
+
+    ABinderProcess_joinThreadPool();
+    return EXIT_FAILURE; // should not reach
+}