LockAgent: Add ability to generate a native crash (5e2a8849) · Commits · e / os / android_frameworks_base

tools/lock_agent/Android.bp

+4 −0

Original line number	Diff line number	Diff line
		@@ -15,6 +15,8 @@ cc_library {
		include_dirs: [
		// NDK headers aren't available in platform NDK builds.
		"libnativehelper/include_jni",
		// Use ScopedUtfChars.
		"libnativehelper/header_only_include",
		],
		header_libs: [
		"libopenjdkjvmti_headers",
		@@ -33,6 +35,8 @@ cc_binary_host {
		include_dirs: [
		// NDK headers aren't available in platform NDK builds.
		"libnativehelper/include_jni",
		// Use ScopedUtfChars.
		"libnativehelper/header_only_include",
		],
		header_libs: [
		"libopenjdkjvmti_headers",

tools/lock_agent/agent.cpp

+58 −1

Original line number	Diff line number	Diff line
		@@ -19,6 +19,8 @@
		#include <memory>
		#include <sstream>

		#include <unistd.h>

		#include <jni.h>

		#include <jvmti.h>
		@@ -26,10 +28,14 @@
		#include <android-base/file.h>
		#include <android-base/logging.h>
		#include <android-base/macros.h>
		#include <android-base/strings.h>
		#include <android-base/unique_fd.h>

		#include <fcntl.h>
		#include <sys/stat.h>
		#include <sys/wait.h>

		#include <nativehelper/scoped_utf_chars.h>

		// We need dladdr.
		#if !defined(__APPLE__) && !defined(_WIN32)
		@@ -61,6 +67,7 @@
		namespace {

		JavaVM* gJavaVM = nullptr;
		bool gForkCrash = false;

		// Converts a class name to a type descriptor
		// (ex. "java.lang.String" to "Ljava/lang/String;")
		@@ -372,7 +379,7 @@ void prepareHook(jvmtiEnv* env) {
		}
		}

		jint attach(JavaVM* vm, char* options ATTRIBUTE_UNUSED, void* reserved ATTRIBUTE_UNUSED) {
		jint attach(JavaVM* vm, char* options, void* reserved ATTRIBUTE_UNUSED) {
		gJavaVM = vm;

		jvmtiEnv* env;
		@@ -383,9 +390,59 @@ jint attach(JavaVM* vm, char* options ATTRIBUTE_UNUSED, void* reserved ATTRIBUTE

		prepareHook(env);

		std::vector<std::string> config = android::base::Split(options, ",");
		for (const std::string& c : config) {
		if (c == "native_crash") {
		gForkCrash = true;
		}
		}

		return JVMTI_ERROR_NONE;
		}

		extern "C" JNIEXPORT
		jboolean JNICALL Java_com_android_lock_1checker_LockHook_getNativeHandlingConfig(JNIEnv*, jclass) {
		return gForkCrash ? JNI_TRUE : JNI_FALSE;
		}

		extern "C" JNIEXPORT void JNICALL Java_com_android_lock_1checker_LockHook_nWtf(JNIEnv* env, jclass,
		jstring msg) {
		if (!gForkCrash \|\| msg == nullptr) {
		return;
		}

		// Create a native crash with the given message. Decouple from the current crash to create a
		// tombstone but continue on.
		//
		// TODO: Once there are not so many reports, consider making this fatal for the calling process.
		ScopedUtfChars utf(env, msg);
		if (utf.c_str() == nullptr) {
		return;
		}
		const char* args[] = {
		"/system/bin/lockagent_crasher",
		utf.c_str(),
		nullptr
		};
		pid_t pid = fork();
		if (pid < 0) {
		return;
		}
		if (pid == 0) {
		// Double fork so we return quickly. Leave init to deal with the zombie.
		pid_t pid2 = fork();
		if (pid2 == 0) {
		execv(args[0], const_cast<char* const*>(args));
		_exit(1);
		__builtin_unreachable();
		}
		_exit(0);
		__builtin_unreachable();
		}
		int status;
		waitpid(pid, &status, 0); // Ignore any results.
		}

		extern "C" JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM* vm, char* options, void* reserved) {
		return attach(vm, options, reserved);
		}

tools/lock_agent/java/com/android/lock_checker/LockHook.java

+11 −0

Original line number	Diff line number	Diff line
		@@ -72,14 +72,20 @@ public class LockHook {

		private static final LockChecker[] sCheckers;

		private static boolean sNativeHandling = false;

		static {
		sHandlerThread = new HandlerThread("LockHook:wtf", Process.THREAD_PRIORITY_BACKGROUND);
		sHandlerThread.start();
		sHandler = new WtfHandler(sHandlerThread.getLooper());

		sCheckers = new LockChecker[] { new OnThreadLockChecker() };

		sNativeHandling = getNativeHandlingConfig();
		}

		private static native boolean getNativeHandlingConfig();

		static <T> boolean shouldDumpStacktrace(StacktraceHasher hasher, Map<String, T> dumpedSet,
		T val, AnnotatedStackTraceElement[] st, int from, int to) {
		final String stacktraceHash = hasher.stacktraceHash(st, from, to);
		@@ -175,7 +181,12 @@ public class LockHook {
		private static void handleViolation(Violation v) {
		String msg = v.toString();
		Log.wtf(TAG, msg);
		if (sNativeHandling) {
		nWtf(msg); // Also send to native.
		}
		}

		private static native void nWtf(String msg);

		/**
		* Generates a hash for a given stacktrace of a {@link Throwable}.