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/Android.bp b/libs/binderdebug/Android.bp
new file mode 100644
index 0000000..343246a
--- /dev/null
+++ b/libs/binderdebug/Android.bp
@@ -0,0 +1,28 @@
+// 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.
+
+cc_library {
+    name: "libbinderdebug",
+    vendor_available: true,
+    shared_libs: [
+        "libbase",
+        "libbinder",
+    ],
+    srcs: [
+        "BinderDebug.cpp",
+    ],
+    export_include_dirs: [
+        "include",
+    ],
+}
diff --git a/libs/binderdebug/BinderDebug.cpp b/libs/binderdebug/BinderDebug.cpp
new file mode 100644
index 0000000..b435dba
--- /dev/null
+++ b/libs/binderdebug/BinderDebug.cpp
@@ -0,0 +1,119 @@
+/*
+ * 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 <android-base/parseint.h>
+#include <android-base/strings.h>
+#include <binder/Binder.h>
+#include <sys/types.h>
+#include <fstream>
+#include <regex>
+
+#include <binderdebug/BinderDebug.h>
+
+namespace android {
+
+static std::string contextToString(BinderDebugContext context) {
+    switch (context) {
+        case BinderDebugContext::BINDER:
+            return "binder";
+        case BinderDebugContext::HWBINDER:
+            return "hwbinder";
+        case BinderDebugContext::VNDBINDER:
+            return "vndbinder";
+        default:
+            return std::string();
+    }
+}
+
+static status_t scanBinderContext(pid_t pid, const std::string& contextName,
+                                  std::function<void(const std::string&)> eachLine) {
+    std::ifstream ifs("/dev/binderfs/binder_logs/proc/" + std::to_string(pid));
+    if (!ifs.is_open()) {
+        ifs.open("/d/binder/proc/" + std::to_string(pid));
+        if (!ifs.is_open()) {
+            return -errno;
+        }
+    }
+    static const std::regex kContextLine("^context (\\w+)$");
+
+    bool isDesiredContext = false;
+    std::string line;
+    std::smatch match;
+    while (getline(ifs, line)) {
+        if (std::regex_search(line, match, kContextLine)) {
+            isDesiredContext = match.str(1) == contextName;
+            continue;
+        }
+        if (!isDesiredContext) {
+            continue;
+        }
+        eachLine(line);
+    }
+    return OK;
+}
+
+status_t getBinderPidInfo(BinderDebugContext context, pid_t pid, BinderPidInfo* pidInfo) {
+    std::smatch match;
+    static const std::regex kReferencePrefix("^\\s*node \\d+:\\s+u([0-9a-f]+)\\s+c([0-9a-f]+)\\s+");
+    static const std::regex kThreadPrefix("^\\s*thread \\d+:\\s+l\\s+(\\d)(\\d)");
+    std::string contextStr = contextToString(context);
+    status_t ret = scanBinderContext(pid, contextStr, [&](const std::string& line) {
+        if (std::regex_search(line, match, kReferencePrefix)) {
+            const std::string& ptrString = "0x" + match.str(2); // use number after c
+            uint64_t ptr;
+            if (!::android::base::ParseUint(ptrString.c_str(), &ptr)) {
+                // Should not reach here, but just be tolerant.
+                return;
+            }
+            const std::string proc = " proc ";
+            auto pos = line.rfind(proc);
+            if (pos != std::string::npos) {
+                for (const std::string& pidStr : base::Split(line.substr(pos + proc.size()), " ")) {
+                    int32_t pid;
+                    if (!::android::base::ParseInt(pidStr, &pid)) {
+                        return;
+                    }
+                    pidInfo->refPids[ptr].push_back(pid);
+                }
+            }
+
+            return;
+        }
+        if (std::regex_search(line, match, kThreadPrefix)) {
+            // "1" is waiting in binder driver
+            // "2" is poll. It's impossible to tell if these are in use.
+            //     and HIDL default code doesn't use it.
+            bool isInUse = match.str(1) != "1";
+            // "0" is a thread that has called into binder
+            // "1" is looper thread
+            // "2" is main looper thread
+            bool isBinderThread = match.str(2) != "0";
+            if (!isBinderThread) {
+                return;
+            }
+            if (isInUse) {
+                pidInfo->threadUsage++;
+            }
+
+            pidInfo->threadCount++;
+            return;
+        }
+        return;
+    });
+    return ret;
+}
+
+} // namespace  android
diff --git a/libs/binderdebug/TEST_MAPPING b/libs/binderdebug/TEST_MAPPING
new file mode 100644
index 0000000..2f3353e
--- /dev/null
+++ b/libs/binderdebug/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+  "presubmit": [
+    {
+      "name": "libbinderdebug_test"
+    }
+  ]
+}
diff --git a/libs/binderdebug/include/binderdebug/BinderDebug.h b/libs/binderdebug/include/binderdebug/BinderDebug.h
new file mode 100644
index 0000000..14a0ef3
--- /dev/null
+++ b/libs/binderdebug/include/binderdebug/BinderDebug.h
@@ -0,0 +1,37 @@
+/*
+ * 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.
+ */
+#pragma once
+
+#include <map>
+#include <vector>
+
+namespace android {
+
+struct BinderPidInfo {
+    std::map<uint64_t, std::vector<pid_t>> refPids; // cookie -> processes which hold binder
+    uint32_t threadUsage;                           // number of threads in use
+    uint32_t threadCount;                           // number of threads total
+};
+
+enum class BinderDebugContext {
+    BINDER,
+    HWBINDER,
+    VNDBINDER,
+};
+
+status_t getBinderPidInfo(BinderDebugContext context, pid_t pid, BinderPidInfo* pidInfo);
+
+} // namespace  android
diff --git a/libs/binderdebug/tests/Android.bp b/libs/binderdebug/tests/Android.bp
new file mode 100644
index 0000000..4c06b1d
--- /dev/null
+++ b/libs/binderdebug/tests/Android.bp
@@ -0,0 +1,30 @@
+// 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.
+
+cc_test {
+    name: "libbinderdebug_test",
+    test_suites: ["general-tests"],
+    srcs: [
+        "binderdebug_test.cpp",
+        "android/binderdebug/test/IControl.aidl",
+    ],
+    shared_libs: [
+        "libbase",
+        "libbinder",
+        "libutils",
+    ],
+    static_libs: ["libbinderdebug"],
+    cflags: ["-Wall", "-Werror"],
+    require_root: true,
+}
diff --git a/libs/binderdebug/tests/android/binderdebug/test/IControl.aidl b/libs/binderdebug/tests/android/binderdebug/test/IControl.aidl
new file mode 100644
index 0000000..8efeb63
--- /dev/null
+++ b/libs/binderdebug/tests/android/binderdebug/test/IControl.aidl
@@ -0,0 +1,22 @@
+/*
+ * 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.
+ */
+
+package android.binderdebug.test;
+
+interface IControl {
+    // Notifies the service to continue execution
+    void Continue();
+}
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