Add libbinderdebug

Allows lshal and dumpsys to share the code to get Binder PID info.

Test: atest libbinderdebug_test lshal_test
Test: diff output of lshal before and after this CL
Bug: 140639610
Change-Id: I04dbe2509673502502ac849ef4ae74147404fc43
diff --git a/libs/binderdebug/tests/binderdebug_test.cpp b/libs/binderdebug/tests/binderdebug_test.cpp
new file mode 100644
index 0000000..ea799c0
--- /dev/null
+++ b/libs/binderdebug/tests/binderdebug_test.cpp
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+#include <binder/Binder.h>
+#include <binder/IServiceManager.h>
+#include <binder/ProcessState.h>
+#include <binder/IPCThreadState.h>
+#include <binderdebug/BinderDebug.h>
+#include <gtest/gtest.h>
+#include <semaphore.h>
+#include <thread>
+
+#include <android/binderdebug/test/BnControl.h>
+#include <android/binderdebug/test/IControl.h>
+
+namespace android {
+namespace binderdebug {
+namespace test {
+
+class Control : public BnControl {
+public:
+    Control() {sem_init(&s, 1, 0);};
+    ::android::binder::Status Continue() override;
+    sem_t s;
+};
+
+::android::binder::Status Control::Continue() {
+    IPCThreadState::self()->flushCommands();
+    sem_post(&s);
+    return binder::Status::ok();
+}
+
+TEST(BinderDebugTests, BinderPid) {
+    BinderPidInfo pidInfo;
+    const auto& status = getBinderPidInfo(BinderDebugContext::BINDER, getpid(), &pidInfo);
+    ASSERT_EQ(status, OK);
+    // There should be one referenced PID for servicemanager
+    EXPECT_TRUE(!pidInfo.refPids.empty());
+}
+
+TEST(BinderDebugTests, BinderThreads) {
+    BinderPidInfo pidInfo;
+    const auto& status = getBinderPidInfo(BinderDebugContext::BINDER, getpid(), &pidInfo);
+    ASSERT_EQ(status, OK);
+    EXPECT_TRUE(pidInfo.threadUsage <= pidInfo.threadCount);
+    // The second looper thread can sometimes take longer to spawn.
+    EXPECT_GE(pidInfo.threadCount, 1);
+}
+
+extern "C" {
+int main(int argc, char** argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+
+    // Create a child/client process to call into the main process so we can ensure
+    // looper thread has been registered before attempting to get the BinderPidInfo
+    pid_t pid = fork();
+    if (pid == 0) {
+        sp<IBinder> binder = android::defaultServiceManager()->getService(String16("binderdebug"));
+        sp<IControl> service;
+        if (binder != nullptr) {
+            service = android::interface_cast<IControl>(binder);
+        }
+        service->Continue();
+        exit(0);
+    }
+    sp<Control> iface = new Control;
+    android::defaultServiceManager()->addService(String16("binderdebug"), iface);
+    android::ProcessState::self()->setThreadPoolMaxThreadCount(8);
+    ProcessState::self()->startThreadPool();
+    sem_wait(&iface->s);
+
+    return RUN_ALL_TESTS();
+}
+} // extern "C"
+} // namespace  test
+} // namespace  binderdebug
+} // namespace  android