LockAgent: Add ability to generate a native crash
Use the crasher to create a tombstone with the violation as the abort
message.
Test: m
Test: manual
Change-Id: I8c5041a4fbffedb11b6b9c564ab1e214551896bf
diff --git a/tools/lock_agent/Android.bp b/tools/lock_agent/Android.bp
index 2125ad6..408946b 100644
--- a/tools/lock_agent/Android.bp
+++ b/tools/lock_agent/Android.bp
@@ -15,6 +15,8 @@
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 @@
include_dirs: [
// NDK headers aren't available in platform NDK builds.
"libnativehelper/include_jni",
+ // Use ScopedUtfChars.
+ "libnativehelper/header_only_include",
],
header_libs: [
"libopenjdkjvmti_headers",
diff --git a/tools/lock_agent/agent.cpp b/tools/lock_agent/agent.cpp
index 59bfa2b..5b1d52e 100644
--- a/tools/lock_agent/agent.cpp
+++ b/tools/lock_agent/agent.cpp
@@ -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 @@
}
}
-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 @@
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);
}
diff --git a/tools/lock_agent/java/com/android/lock_checker/LockHook.java b/tools/lock_agent/java/com/android/lock_checker/LockHook.java
index efab1d2..86c97d3 100644
--- a/tools/lock_agent/java/com/android/lock_checker/LockHook.java
+++ b/tools/lock_agent/java/com/android/lock_checker/LockHook.java
@@ -72,14 +72,20 @@
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);
@@ -175,8 +181,13 @@
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}.
*/