From 8f4319d5a7e471f68ffdc921343da33f9ed803da Mon Sep 17 00:00:00 2001
From: Steven Moreland <smoreland@google.com>
Date: Tue, 17 Nov 2020 22:40:20 +0000
Subject: [PATCH] HwBinder: log exceptions from Java

Before, if there was an uncaught exception from a Java HIDL server,
'Uncaught Exception!' would be printed in logcat, but the actual
exception would only be written to stderr. Now, we use the same binder
functionality to print the error to stdout.

Bug: N/A
Test: manual
Change-Id: I850c3158bad7313013f5e688850ec72cfa2fa686
---
 core/jni/android_os_HwBinder.cpp | 12 +++---------
 core/jni/android_util_Binder.cpp | 25 ++++++++++++++-----------
 core/jni/android_util_Binder.h   |  2 ++
 3 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/core/jni/android_os_HwBinder.cpp b/core/jni/android_os_HwBinder.cpp
index 48f33a6a3d77e..781895eeeabaf 100644
--- a/core/jni/android_os_HwBinder.cpp
+++ b/core/jni/android_os_HwBinder.cpp
@@ -20,6 +20,8 @@
 
 #include "android_os_HwBinder.h"
 
+#include "android_util_Binder.h" // for binder_report_exception
+
 #include "android_os_HwParcel.h"
 #include "android_os_HwRemoteBinder.h"
 
@@ -183,15 +185,7 @@ status_t JHwBinder::onTransact(
         env->ExceptionDescribe();
         env->ExceptionClear();
 
-        // It is illegal to call IsInstanceOf if there is a pending exception.
-        // Attempting to do so results in a JniAbort which crashes the entire process.
-        if (env->IsInstanceOf(excep, gErrorClass)) {
-            /* It's an error */
-            LOG(ERROR) << "Forcefully exiting";
-            _exit(1);
-        } else {
-            LOG(ERROR) << "Uncaught exception!";
-        }
+        binder_report_exception(env, excep, "Uncaught error or exception in hwbinder!");
 
         env->DeleteLocalRef(excep);
     }
diff --git a/core/jni/android_util_Binder.cpp b/core/jni/android_util_Binder.cpp
index 9643b64c68f85..581dc0848a284 100644
--- a/core/jni/android_util_Binder.cpp
+++ b/core/jni/android_util_Binder.cpp
@@ -302,8 +302,9 @@ static void report_java_lang_error(JNIEnv* env, jthrowable error, const char* ms
     report_java_lang_error_fatal_error(env, error, msg);
 }
 
-static void report_exception(JNIEnv* env, jthrowable excep, const char* msg)
-{
+namespace android {
+
+void binder_report_exception(JNIEnv* env, jthrowable excep, const char* msg) {
     env->ExceptionClear();
 
     ScopedLocalRef<jstring> tagstr(env, env->NewStringUTF(LOG_TAG));
@@ -331,6 +332,8 @@ static void report_exception(JNIEnv* env, jthrowable excep, const char* msg)
     }
 }
 
+} // namespace android
+
 class JavaBBinderHolder;
 
 class JavaBBinder : public BBinder
@@ -405,9 +408,9 @@ protected:
 
         if (env->ExceptionCheck()) {
             ScopedLocalRef<jthrowable> excep(env, env->ExceptionOccurred());
-            report_exception(env, excep.get(),
-                "*** Uncaught remote exception!  "
-                "(Exceptions are not yet supported across processes.)");
+            binder_report_exception(env, excep.get(),
+                                    "*** Uncaught remote exception!  "
+                                    "(Exceptions are not yet supported across processes.)");
             res = JNI_FALSE;
         }
 
@@ -421,8 +424,8 @@ protected:
 
         if (env->ExceptionCheck()) {
             ScopedLocalRef<jthrowable> excep(env, env->ExceptionOccurred());
-            report_exception(env, excep.get(),
-                "*** Uncaught exception in onBinderStrictModePolicyChange");
+            binder_report_exception(env, excep.get(),
+                                    "*** Uncaught exception in onBinderStrictModePolicyChange");
         }
 
         // Need to always call through the native implementation of
@@ -567,8 +570,8 @@ public:
                                       jBinderProxy.get());
             if (env->ExceptionCheck()) {
                 jthrowable excep = env->ExceptionOccurred();
-                report_exception(env, excep,
-                        "*** Uncaught exception returned from death notification!");
+                binder_report_exception(env, excep,
+                                        "*** Uncaught exception returned from death notification!");
             }
 
             // Serialize with our containing DeathRecipientList so that we can't
@@ -1163,8 +1166,8 @@ static void android_os_BinderInternal_proxyLimitcallback(int uid)
 
     if (env->ExceptionCheck()) {
         ScopedLocalRef<jthrowable> excep(env, env->ExceptionOccurred());
-        report_exception(env, excep.get(),
-            "*** Uncaught exception in binderProxyLimitCallbackFromNative");
+        binder_report_exception(env, excep.get(),
+                                "*** Uncaught exception in binderProxyLimitCallbackFromNative");
     }
 }
 
diff --git a/core/jni/android_util_Binder.h b/core/jni/android_util_Binder.h
index c109d6c265c39..9098d46ee29c4 100644
--- a/core/jni/android_util_Binder.h
+++ b/core/jni/android_util_Binder.h
@@ -35,6 +35,8 @@ extern void set_dalvik_blockguard_policy(JNIEnv* env, jint strict_policy);
 extern void signalExceptionForError(JNIEnv* env, jobject obj, status_t err,
         bool canThrowRemoteException = false, int parcelSize = 0);
 
+// does not take ownership of the exception, aborts if this is an error
+void binder_report_exception(JNIEnv* env, jthrowable excep, const char* msg);
 }
 
 #endif