Merge "Zygote: Increase wrap-pid timeout to thirty seconds"

am: 81f66ce5ab

Change-Id: I1cc8856ebb68ee83a8d3e62d86b48d497d0eb237

core/java/com/android/internal/os/ZygoteConnection.java

@@ -22,6 +22,9 @@ import static android.system.OsConstants.POLLIN;
 import static android.system.OsConstants.STDERR_FILENO;
 import static android.system.OsConstants.STDIN_FILENO;
 import static android.system.OsConstants.STDOUT_FILENO;
+import static com.android.internal.os.ZygoteConnectionConstants.CONNECTION_TIMEOUT_MILLIS;
+import static com.android.internal.os.ZygoteConnectionConstants.MAX_ZYGOTE_ARGC;
+import static com.android.internal.os.ZygoteConnectionConstants.WRAPPED_PID_TIMEOUT_MILLIS;
 
 import android.net.Credentials;
 import android.net.LocalSocket;
@@ -58,18 +61,6 @@ class ZygoteConnection {
     /** a prototype instance for a future List.toArray() */
     private static final int[][] intArray2d = new int[0][0];
 
-    /**
-     * {@link android.net.LocalSocket#setSoTimeout} value for connections.
-     * Effectively, the amount of time a requestor has between the start of
-     * the request and the completed request. The select-loop mode Zygote
-     * doesn't have the logic to return to the select loop in the middle of
-     * a request, so we need to time out here to avoid being denial-of-serviced.
-     */
-    private static final int CONNECTION_TIMEOUT_MILLIS = 1000;
-
-    /** max number of arguments that a connection can specify */
-    private static final int MAX_ZYGOTE_ARGC = 1024;
-
     /**
      * The command socket.
      *
@@ -858,10 +849,6 @@ class ZygoteConnection {
             try {
                 // Do a busy loop here. We can't guarantee that a failure (and thus an exception
                 // bail) happens in a timely manner.
-                //
-                // We'll wait up to five seconds. This should give enough time for the fork to go
-                // through, but not to trigger the watchdog in the system server.
-                final int SLEEP_IN_MS = 5000;
                 final int BYTES_REQUIRED = 4;  // Bytes in an int.
 
                 StructPollfd fds[] = new StructPollfd[] {
@@ -870,7 +857,7 @@ class ZygoteConnection {
 
                 byte data[] = new byte[BYTES_REQUIRED];
 
-                int remainingSleepTime = SLEEP_IN_MS;
+                int remainingSleepTime = WRAPPED_PID_TIMEOUT_MILLIS;
                 int dataIndex = 0;
                 long startTime = System.nanoTime();
 
@@ -882,7 +869,8 @@ class ZygoteConnection {
 
                     int res = android.system.Os.poll(fds, remainingSleepTime);
                     long endTime = System.nanoTime();
-                    remainingSleepTime = SLEEP_IN_MS - (int)((endTime - startTime) / 1000000l);
+                    int elapsedTimeMs = (int)((endTime - startTime) / 1000000l);
+                    remainingSleepTime = WRAPPED_PID_TIMEOUT_MILLIS - elapsedTimeMs;
 
                     if (res > 0) {
                         if ((fds[0].revents & POLLIN) != 0) {

core/java/com/android/internal/os/ZygoteConnectionConstants.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.internal.os;
+
+/**
+ * Sharable zygote constants.
+ *
+ * @hide
+ */
+public class ZygoteConnectionConstants {
+    /**
+     * {@link android.net.LocalSocket#setSoTimeout} value for connections.
+     * Effectively, the amount of time a requestor has between the start of
+     * the request and the completed request. The select-loop mode Zygote
+     * doesn't have the logic to return to the select loop in the middle of
+     * a request, so we need to time out here to avoid being denial-of-serviced.
+     */
+    public static final int CONNECTION_TIMEOUT_MILLIS = 1000;
+
+    /** max number of arguments that a connection can specify */
+    public static final int MAX_ZYGOTE_ARGC = 1024;
+
+    /**
+     * Wait time for a wrapped app to report back its pid.
+     *
+     * We'll wait up to thirty seconds. This should give enough time for the fork
+     * to go through, but not to trigger the watchdog in the system server (by default
+     * sixty seconds).
+     *
+     * WARNING: This may trigger the watchdog in debug mode. However, to support
+     *          wrapping on lower-end devices we do not have much choice.
+     */
+    public static final int WRAPPED_PID_TIMEOUT_MILLIS = 30000;
+}

services/core/java/com/android/server/Watchdog.java

@@ -19,6 +19,7 @@ package com.android.server;
 import android.app.IActivityController;
 import android.os.Binder;
 import android.os.RemoteException;
+import com.android.internal.os.ZygoteConnectionConstants;
 import com.android.server.am.ActivityManagerService;
 
 import android.content.BroadcastReceiver;
@@ -57,6 +58,11 @@ public class Watchdog extends Thread {
     // Set this to true to have the watchdog record kernel thread stacks when it fires
     static final boolean RECORD_KERNEL_THREADS = true;
 
+    // Note 1: Do not lower this value below thirty seconds without tightening the invoke-with
+    //         timeout in com.android.internal.os.ZygoteConnection, or wrapped applications
+    //         can trigger the watchdog.
+    // Note 2: The debug value is already below the wait time in ZygoteConnection. Wrapped
+    //         applications may not work with a debug build. CTS will fail.
     static final long DEFAULT_TIMEOUT = DB ? 10*1000 : 60*1000;
     static final long CHECK_INTERVAL = DEFAULT_TIMEOUT / 2;
 
@@ -261,6 +267,10 @@ public class Watchdog extends Thread {
 
         // Initialize monitor for Binder threads.
         addMonitor(new BinderThreadMonitor());
+
+        // See the notes on DEFAULT_TIMEOUT.
+        assert DB ||
+                DEFAULT_TIMEOUT > ZygoteConnectionConstants.WRAPPED_PID_TIMEOUT_MILLIS;
     }
 
     public void init(Context context, ActivityManagerService activity) {