From cd910c2131cec47f8e9f513f39a642a0dbedc238 Mon Sep 17 00:00:00 2001
From: Brad Ebinger <breadley@google.com>
Date: Fri, 5 Feb 2021 00:27:08 +0000
Subject: [PATCH] Discard dead MmTelFeature Binder Instances

When the phone process crashes and the IMS service is in
a separate process, there is a condition where the ImsService may
still stay unbound, but alive and not torn down. In this case,
when the phone process comes back up and tries to register new
binder callbacks, detect that the old binder callbacks are dead
and discard instead of throwing an exception.

Bug: 179217608
Test: kill phone process
Change-Id: I4fc3b6d15fe19ebaf1fc52dab92a615a761222f8
---
 .../java/android/telephony/ims/stub/ImsEcbmImplBase.java  | 8 ++++++--
 .../telephony/ims/stub/ImsMultiEndpointImplBase.java      | 4 ++++
 .../java/android/telephony/ims/stub/ImsUtImplBase.java    | 7 +++++++
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/telephony/java/android/telephony/ims/stub/ImsEcbmImplBase.java b/telephony/java/android/telephony/ims/stub/ImsEcbmImplBase.java
index 2e35d27614d17..5f8e93d02a00b 100644
--- a/telephony/java/android/telephony/ims/stub/ImsEcbmImplBase.java
+++ b/telephony/java/android/telephony/ims/stub/ImsEcbmImplBase.java
@@ -44,8 +44,12 @@ public class ImsEcbmImplBase {
         @Override
         public void setListener(IImsEcbmListener listener) {
             synchronized (mLock) {
-                if (mImsEcbm != null && listener != null && Objects.equals(
-                        mImsEcbm.asBinder(), listener.asBinder())) {
+                if (mListener != null && !mListener.asBinder().isBinderAlive()) {
+                    Log.w(TAG, "setListener: discarding dead Binder");
+                    mListener = null;
+                }
+                if (mListener != null && listener != null && Objects.equals(
+                        mListener.asBinder(), listener.asBinder())) {
                     return;
                 }
                 if (listener == null) {
diff --git a/telephony/java/android/telephony/ims/stub/ImsMultiEndpointImplBase.java b/telephony/java/android/telephony/ims/stub/ImsMultiEndpointImplBase.java
index 555a47eb82001..8e961acc7b36d 100644
--- a/telephony/java/android/telephony/ims/stub/ImsMultiEndpointImplBase.java
+++ b/telephony/java/android/telephony/ims/stub/ImsMultiEndpointImplBase.java
@@ -48,6 +48,10 @@ public class ImsMultiEndpointImplBase {
         @Override
         public void setListener(IImsExternalCallStateListener listener) throws RemoteException {
             synchronized (mLock) {
+                if (mListener != null && !mListener.asBinder().isBinderAlive()) {
+                    Log.w(TAG, "setListener: discarding dead Binder");
+                    mListener = null;
+                }
                 if (mListener != null && listener != null && Objects.equals(
                         mListener.asBinder(), listener.asBinder())) {
                     return;
diff --git a/telephony/java/android/telephony/ims/stub/ImsUtImplBase.java b/telephony/java/android/telephony/ims/stub/ImsUtImplBase.java
index eef4fcaceeaf8..83b89aa8e8147 100644
--- a/telephony/java/android/telephony/ims/stub/ImsUtImplBase.java
+++ b/telephony/java/android/telephony/ims/stub/ImsUtImplBase.java
@@ -23,6 +23,7 @@ import android.annotation.SystemApi;
 import android.os.Bundle;
 import android.os.RemoteException;
 import android.telephony.ims.ImsUtListener;
+import android.util.Log;
 
 import com.android.ims.internal.IImsUt;
 import com.android.ims.internal.IImsUtListener;
@@ -41,6 +42,7 @@ import java.util.Objects;
 // will break other implementations of ImsUt maintained by other ImsServices.
 @SystemApi
 public class ImsUtImplBase {
+    private static final String TAG = "ImsUtImplBase";
     /**
      * Bar all incoming calls. (See 3GPP TS 24.611)
      * @hide
@@ -207,6 +209,11 @@ public class ImsUtImplBase {
         @Override
         public void setListener(IImsUtListener listener) throws RemoteException {
             synchronized (mLock) {
+                if (mUtListener != null
+                        && !mUtListener.getListenerInterface().asBinder().isBinderAlive()) {
+                    Log.w(TAG, "setListener: discarding dead Binder");
+                    mUtListener = null;
+                }
                 if (mUtListener != null && listener != null && Objects.equals(
                         mUtListener.getListenerInterface().asBinder(), listener.asBinder())) {
                     return;