Increase activity timeouts when using a wrapper process.

This patch enables the Zygote to tell the ActivityManager when
it has started a process with a wrapper attached so that the
ActivityManager can allow it extra time to start up or process
events.

This is useful when wrapping an app with Valgrind or other tools
which add significant runtime overhead.

Bug: 4584468
Change-Id: I5db6f2f15cd30b0ec40f547d2fadfa216de2926d

2 files changed, 34 insertions, 25 deletions

diff --git a/core/java/android/os/Process.java b/core/java/android/os/Process.java
index 269e50e..5b1f563 100644
--- a/core/java/android/os/Process.java
+++ b/core/java/android/os/Process.java
@@ -270,13 +270,12 @@ public class Process {
      * @param targetSdkVersion The target SDK version for the app.
      * @param zygoteArgs Additional arguments to supply to the zygote process.
      * 
-     * @return int If > 0 the pid of the new process; if 0 the process is
-     *         being emulated by a thread
+     * @return An object that describes the result of the attempt to start the process.
      * @throws RuntimeException on fatal start failure
      * 
      * {@hide}
      */
-    public static final int start(final String processClass,
+    public static final ProcessStartResult start(final String processClass,
                                   final String niceName,
                                   int uid, int gid, int[] gids,
                                   int debugFlags, int targetSdkVersion,
@@ -376,14 +375,11 @@ public class Process {
      * and returns the child's pid. Please note: the present implementation
      * replaces newlines in the argument list with spaces.
      * @param args argument list
-     * @return PID of new child process
+     * @return An object that describes the result of the attempt to start the process.
      * @throws ZygoteStartFailedEx if process start failed for any reason
      */
-    private static int zygoteSendArgsAndGetPid(ArrayList<String> args)
+    private static ProcessStartResult zygoteSendArgsAndGetResult(ArrayList<String> args)
             throws ZygoteStartFailedEx {
-
-        int pid;
-
         openZygoteSocketIfNeeded();
 
         try {
@@ -394,7 +390,8 @@ public class Process {
              * b) a number of newline-separated argument strings equal to count
              *
              * After the zygote process reads these it will write the pid of
-             * the child or -1 on failure.
+             * the child or -1 on failure, followed by boolean to
+             * indicate whether a wrapper process was used.
              */
 
             sZygoteWriter.write(Integer.toString(args.size()));
@@ -414,11 +411,13 @@ public class Process {
             sZygoteWriter.flush();
 
             // Should there be a timeout on this?
-            pid = sZygoteInputStream.readInt();
-
-            if (pid < 0) {
+            ProcessStartResult result = new ProcessStartResult();
+            result.pid = sZygoteInputStream.readInt();
+            if (result.pid < 0) {
                 throw new ZygoteStartFailedEx("fork() failed");
             }
+            result.usingWrapper = sZygoteInputStream.readBoolean();
+            return result;
         } catch (IOException ex) {
             try {
                 if (sZygoteSocket != null) {
@@ -433,8 +432,6 @@ public class Process {
 
             throw new ZygoteStartFailedEx(ex);
         }
-
-        return pid;
     }
 
     /**
@@ -449,18 +446,16 @@ public class Process {
      * @param debugFlags Additional flags.
      * @param targetSdkVersion The target SDK version for the app.
      * @param extraArgs Additional arguments to supply to the zygote process.
-     * @return PID
+     * @return An object that describes the result of the attempt to start the process.
      * @throws ZygoteStartFailedEx if process start failed for any reason
      */
-    private static int startViaZygote(final String processClass,
+    private static ProcessStartResult startViaZygote(final String processClass,
                                   final String niceName,
                                   final int uid, final int gid,
                                   final int[] gids,
                                   int debugFlags, int targetSdkVersion,
                                   String[] extraArgs)
                                   throws ZygoteStartFailedEx {
-        int pid;
-
         synchronized(Process.class) {
             ArrayList<String> argsForZygote = new ArrayList<String>();
 
@@ -516,15 +511,9 @@ public class Process {
                     argsForZygote.add(arg);
                 }
             }
-            
-            pid = zygoteSendArgsAndGetPid(argsForZygote);
-        }
 
-        if (pid <= 0) {
-            throw new ZygoteStartFailedEx("zygote start failed:" + pid);
+            return zygoteSendArgsAndGetResult(argsForZygote);
         }
-
-        return pid;
     }
     
     /**
@@ -808,4 +797,21 @@ public class Process {
      * @hide
      */
     public static final native long getPss(int pid);
+
+    /**
+     * Specifies the outcome of having started a process.
+     * @hide
+     */
+    public static final class ProcessStartResult {
+        /**
+         * The PID of the newly started process.
+         * Always >= 0.  (If the start failed, an exception will have been thrown instead.)
+         */
+        public int pid;
+
+        /**
+         * True if the process was started with a wrapper attached.
+         */
+        public boolean usingWrapper;
+    }
 }
diff --git a/core/java/com/android/internal/os/ZygoteConnection.java b/core/java/com/android/internal/os/ZygoteConnection.java
index a3b7795..9af7e96 100644
--- a/core/java/com/android/internal/os/ZygoteConnection.java
+++ b/core/java/com/android/internal/os/ZygoteConnection.java
@@ -900,6 +900,7 @@ class ZygoteConnection {
             }
         }
 
+        boolean usingWrapper = false;
         if (pipeFd != null && pid > 0) {
             DataInputStream is = new DataInputStream(new FileInputStream(pipeFd));
             int innerPid = -1;
@@ -924,6 +925,7 @@ class ZygoteConnection {
                 if (parentPid > 0) {
                     Log.i(TAG, "Wrapped process has pid " + innerPid);
                     pid = innerPid;
+                    usingWrapper = true;
                 } else {
                     Log.w(TAG, "Wrapped process reported a pid that is not a child of "
                             + "the process that we forked: childPid=" + pid
@@ -934,6 +936,7 @@ class ZygoteConnection {
 
         try {
             mSocketOutStream.writeInt(pid);
+            mSocketOutStream.writeBoolean(usingWrapper);
         } catch (IOException ex) {
             Log.e(TAG, "Error reading from command socket", ex);
             return true;