From 80299748cc7ed5f59cb65122459b036b74150d4a Mon Sep 17 00:00:00 2001
From: Phil Burk <philburk@google.com>
Date: Tue, 5 Apr 2016 14:19:53 -0700
Subject: [PATCH] MidiDevice: fix connectPorts for same Process

If connectPorts() was called for a device in the same process then
the connection would die when the ParcelFileDescriptor was closed.

Bug: 26406775
Change-Id: Id0538452593b4761ac2a93d366ade76d2e35ce73
Signed-off-by: Phil Burk <philburk@google.com>
---
 .../java/android/media/midi/IMidiDeviceServer.aidl |  3 ++-
 media/java/android/media/midi/MidiDevice.java      | 14 +++++++++++---
 .../java/android/media/midi/MidiDeviceServer.java  |  3 ++-
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/media/java/android/media/midi/IMidiDeviceServer.aidl b/media/java/android/media/midi/IMidiDeviceServer.aidl
index c2cc2b9f93794..d5115de4a0483 100644
--- a/media/java/android/media/midi/IMidiDeviceServer.aidl
+++ b/media/java/android/media/midi/IMidiDeviceServer.aidl
@@ -28,7 +28,8 @@ interface IMidiDeviceServer
     void closeDevice();
 
     // connects the input port pfd to the specified output port
-    void connectPorts(IBinder token, in ParcelFileDescriptor pfd, int outputPortNumber);
+    // Returns the PID of the called process.
+    int connectPorts(IBinder token, in ParcelFileDescriptor pfd, int outputPortNumber);
 
     MidiDeviceInfo getDeviceInfo();
     void setDeviceInfo(in MidiDeviceInfo deviceInfo);
diff --git a/media/java/android/media/midi/MidiDevice.java b/media/java/android/media/midi/MidiDevice.java
index e1990cd6fbbb1..e4588fe3abc53 100644
--- a/media/java/android/media/midi/MidiDevice.java
+++ b/media/java/android/media/midi/MidiDevice.java
@@ -19,6 +19,7 @@ package android.media.midi;
 import android.os.Binder;
 import android.os.IBinder;
 import android.os.ParcelFileDescriptor;
+import android.os.Process;
 import android.os.RemoteException;
 import android.util.Log;
 
@@ -181,9 +182,16 @@ public final class MidiDevice implements Closeable {
         }
          try {
             IBinder token = new Binder();
-            mDeviceServer.connectPorts(token, pfd, outputPortNumber);
-            // close our copy of the file descriptor
-            IoUtils.closeQuietly(pfd);
+            int calleePid = mDeviceServer.connectPorts(token, pfd, outputPortNumber);
+            // If the service is a different Process then it will duplicate the pfd
+            // and we can safely close this one.
+            // But if the service is in the same Process then closing the pfd will
+            // kill the connection. So don't do that.
+            if (calleePid != Process.myPid()) {
+                // close our copy of the file descriptor
+                IoUtils.closeQuietly(pfd);
+            }
+
             return new MidiConnection(token, inputPort);
         } catch (RemoteException e) {
             Log.e(TAG, "RemoteException in connectPorts");
diff --git a/media/java/android/media/midi/MidiDeviceServer.java b/media/java/android/media/midi/MidiDeviceServer.java
index 19ff624601556..f0abf711ba162 100644
--- a/media/java/android/media/midi/MidiDeviceServer.java
+++ b/media/java/android/media/midi/MidiDeviceServer.java
@@ -254,7 +254,7 @@ public final class MidiDeviceServer implements Closeable {
         }
 
         @Override
-        public void connectPorts(IBinder token, ParcelFileDescriptor pfd,
+        public int connectPorts(IBinder token, ParcelFileDescriptor pfd,
                 int outputPortNumber) {
             MidiInputPort inputPort = new MidiInputPort(pfd, outputPortNumber);
             MidiDispatcher dispatcher = mOutputPortDispatchers[outputPortNumber];
@@ -270,6 +270,7 @@ public final class MidiDeviceServer implements Closeable {
             synchronized (mPortClients) {
                 mPortClients.put(token, client);
             }
+            return Process.myPid(); // for caller to detect same process ID
         }
 
         @Override