Merge "Support wrapping app processes to inject debug instrumentation. Bug: 4437846"

5 files changed, 517 insertions, 139 deletions

diff --git a/core/java/android/os/Process.java b/core/java/android/os/Process.java
index e1fdfb6d3e1d..e128974ebb90 100644
--- a/core/java/android/os/Process.java
+++ b/core/java/android/os/Process.java
@@ -257,13 +257,12 @@ public class Process {
      * @param enableDebugger True if debugging should be enabled for this process.
      * @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,
@@ -294,8 +293,7 @@ public class Process {
             } else {
                 new Thread(runnable).start();
             }
-            
-            return 0;
+            return new ProcessStartResult();
         }
     }
     
@@ -303,7 +301,7 @@ public class Process {
      * Start a new process.  Don't supply a custom nice name.
      * {@hide}
      */
-    public static final int start(String processClass, int uid, int gid,
+    public static final ProcessStartResult start(String processClass, int uid, int gid,
             int[] gids, int debugFlags, String[] zygoteArgs) {
         return start(processClass, "", uid, gid, gids, 
                 debugFlags, zygoteArgs);
@@ -418,14 +416,11 @@ 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 {
@@ -436,7 +431,8 @@ 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()));
@@ -456,11 +452,13 @@ 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) {
@@ -475,8 +473,6 @@ public class Process {
 
             throw new ZygoteStartFailedEx(ex);
         }
-
-        return pid;
     }
 
     /**
@@ -490,18 +486,16 @@ public class Process {
      * new process should setgroup() to.
      * @param enableDebugger True if debugging should be enabled for this process.
      * @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,
                                   String[] extraArgs)
                                   throws ZygoteStartFailedEx {
-        int pid;
-
         synchronized(Process.class) {
             ArrayList<String> argsForZygote = new ArrayList<String>();
 
@@ -553,15 +547,9 @@ public class Process {
                     argsForZygote.add(arg);
                 }
             }
-            
-            pid = zygoteSendArgsAndGetPid(argsForZygote);
-        }
 
-        if (pid <= 0) {
-            throw new ZygoteStartFailedEx("zygote start failed:" + pid);
+            return zygoteSendArgsAndGetResult(argsForZygote);
         }
-
-        return pid;
     }
     
     /**
@@ -616,6 +604,20 @@ public class Process {
     }
 
     /**
+     * Returns the parent process id for a currently running process.
+     * @param pid the process id
+     * @return the parent process id of the process, or -1 if the process is not running.
+     * @hide
+     */
+    public static final int getParentPid(int pid) {
+        String[] procStatusLabels = { "PPid:" };
+        long[] procStatusValues = new long[1];
+        procStatusValues[0] = -1;
+        Process.readProcLines("/proc/" + pid + "/status", procStatusLabels, procStatusValues);
+        return (int) procStatusValues[0];
+    }
+
+    /**
      * Set the priority of a thread, based on Linux priorities.
      * 
      * @param tid The identifier of the thread/process to change.
@@ -826,4 +828,21 @@ 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/RuntimeInit.java b/core/java/com/android/internal/os/RuntimeInit.java
index 59600dcdc455..2de90bafa6ea 100644
--- a/core/java/com/android/internal/os/RuntimeInit.java
+++ b/core/java/com/android/internal/os/RuntimeInit.java
@@ -23,7 +23,6 @@ import android.os.Debug;
 import android.os.IBinder;
 import android.os.Process;
 import android.os.SystemProperties;
-import android.util.Config;
 import android.util.Log;
 import android.util.Slog;
 
@@ -46,6 +45,7 @@ import org.apache.harmony.luni.internal.util.TimezoneGetter;
  */
 public class RuntimeInit {
     private final static String TAG = "AndroidRuntime";
+    private final static boolean DEBUG = false;
 
     /** true if commonInit() has been called */
     private static boolean initialized;
@@ -90,14 +90,14 @@ public class RuntimeInit {
     }
 
     private static final void commonInit() {
-        if (Config.LOGV) Slog.d(TAG, "Entered RuntimeInit!");
+        if (DEBUG) Slog.d(TAG, "Entered RuntimeInit!");
 
         /* set default handler; this applies to all threads in the VM */
         Thread.setDefaultUncaughtExceptionHandler(new UncaughtHandler());
 
         int hasQwerty = getQwertyKeyboard();
 
-        if (Config.LOGV) Slog.d(TAG, ">>>>> qwerty keyboard = " + hasQwerty);
+        if (DEBUG) Slog.d(TAG, ">>>>> qwerty keyboard = " + hasQwerty);
         if (hasQwerty == 1) {
             System.setProperty("qwerty", "1");
         }
@@ -184,11 +184,6 @@ public class RuntimeInit {
      */
     private static void invokeStaticMain(String className, String[] argv)
             throws ZygoteInit.MethodAndArgsCaller {
-
-        // We want to be fairly aggressive about heap utilization, to avoid
-        // holding on to a lot of memory that isn't needed.
-        VMRuntime.getRuntime().setTargetHeapUtilization(0.75f);
-
         Class<?> cl;
 
         try {
@@ -226,6 +221,13 @@ public class RuntimeInit {
     }
 
     public static final void main(String[] argv) {
+        if (argv.length == 2 && argv[1].equals("application")) {
+            if (DEBUG) Slog.d(TAG, "RuntimeInit: Starting application");
+            redirectLogStreams();
+        } else {
+            if (DEBUG) Slog.d(TAG, "RuntimeInit: Starting tool");
+        }
+
         commonInit();
 
         /*
@@ -234,7 +236,7 @@ public class RuntimeInit {
          */
         finishInit();
 
-        if (Config.LOGV) Slog.d(TAG, "Leaving RuntimeInit!");
+        if (DEBUG) Slog.d(TAG, "Leaving RuntimeInit!");
     }
 
     public static final native void finishInit();
@@ -246,7 +248,6 @@ public class RuntimeInit {
      *
      * Current recognized args:
      * <ul>
-     *   <li> --nice-name=<i>nice name to appear in ps</i>
      *   <li> <code> [--] &lt;start class name&gt;  &lt;args&gt;
      * </ul>
      *
@@ -254,43 +255,60 @@ public class RuntimeInit {
      */
     public static final void zygoteInit(String[] argv)
             throws ZygoteInit.MethodAndArgsCaller {
-        // TODO: Doing this here works, but it seems kind of arbitrary. Find
-        // a better place. The goal is to set it up for applications, but not
-        // tools like am.
-        System.setOut(new AndroidPrintStream(Log.INFO, "System.out"));
-        System.setErr(new AndroidPrintStream(Log.WARN, "System.err"));
+        if (DEBUG) Slog.d(TAG, "RuntimeInit: Starting application from zygote");
+
+        redirectLogStreams();
 
         commonInit();
         zygoteInitNative();
 
-        int curArg = 0;
-        for ( /* curArg */ ; curArg < argv.length; curArg++) {
-            String arg = argv[curArg];
-
-            if (arg.equals("--")) {
-                curArg++;
-                break;
-            } else if (!arg.startsWith("--")) {
-                break;
-            } else if (arg.startsWith("--nice-name=")) {
-                String niceName = arg.substring(arg.indexOf('=') + 1);
-                Process.setArgV0(niceName);
-            }
-        }
+        applicationInit(argv);
+    }
+
+    /**
+     * The main function called when an application is started through a
+     * wrapper process.
+     *
+     * When the wrapper starts, the runtime starts {@link RuntimeInit#main}
+     * which calls {@link WrapperInit#main} which then calls this method.
+     * So we don't need to call commonInit() here.
+     *
+     * @param argv arg strings
+     */
+    public static void wrapperInit(String[] argv)
+            throws ZygoteInit.MethodAndArgsCaller {
+        if (DEBUG) Slog.d(TAG, "RuntimeInit: Starting application from wrapper");
+
+        applicationInit(argv);
+    }
 
-        if (curArg == argv.length) {
-            Slog.e(TAG, "Missing classname argument to RuntimeInit!");
+    private static void applicationInit(String[] argv)
+            throws ZygoteInit.MethodAndArgsCaller {
+        // We want to be fairly aggressive about heap utilization, to avoid
+        // holding on to a lot of memory that isn't needed.
+        VMRuntime.getRuntime().setTargetHeapUtilization(0.75f);
+
+        final Arguments args;
+        try {
+            args = new Arguments(argv);
+        } catch (IllegalArgumentException ex) {
+            Slog.e(TAG, ex.getMessage());
             // let the process exit
             return;
         }
 
         // Remaining arguments are passed to the start class's static main
+        invokeStaticMain(args.startClass, args.startArgs);
+    }
 
-        String startClass = argv[curArg++];
-        String[] startArgs = new String[argv.length - curArg];
-
-        System.arraycopy(argv, curArg, startArgs, 0, startArgs.length);
-        invokeStaticMain(startClass, startArgs);
+    /**
+     * Redirect System.out and System.err to the Android log.
+     */
+    public static void redirectLogStreams() {
+        System.out.close();
+        System.setOut(new AndroidPrintStream(Log.INFO, "System.out"));
+        System.err.close();
+        System.setErr(new AndroidPrintStream(Log.WARN, "System.err"));
     }
 
     public static final native void zygoteInitNative();
@@ -353,4 +371,55 @@ public class RuntimeInit {
         // Register handlers for DDM messages.
         android.ddm.DdmRegister.registerHandlers();
     }
+
+    /**
+     * Handles argument parsing for args related to the runtime.
+     *
+     * Current recognized args:
+     * <ul>
+     *   <li> <code> [--] &lt;start class name&gt;  &lt;args&gt;
+     * </ul>
+     */
+    static class Arguments {
+        /** first non-option argument */
+        String startClass;
+
+        /** all following arguments */
+        String[] startArgs;
+
+        /**
+         * Constructs instance and parses args
+         * @param args runtime command-line args
+         * @throws IllegalArgumentException
+         */
+        Arguments(String args[]) throws IllegalArgumentException {
+            parseArgs(args);
+        }
+
+        /**
+         * Parses the commandline arguments intended for the Runtime.
+         */
+        private void parseArgs(String args[])
+                throws IllegalArgumentException {
+            int curArg = 0;
+            for (; curArg < args.length; curArg++) {
+                String arg = args[curArg];
+
+                if (arg.equals("--")) {
+                    curArg++;
+                    break;
+                } else if (!arg.startsWith("--")) {
+                    break;
+                }
+            }
+
+            if (curArg == args.length) {
+                throw new IllegalArgumentException("Missing classname argument to RuntimeInit!");
+            }
+
+            startClass = args[curArg++];
+            startArgs = new String[args.length - curArg];
+            System.arraycopy(args, curArg, startArgs, 0, startArgs.length);
+        }
+    }
 }
diff --git a/core/java/com/android/internal/os/WrapperInit.java b/core/java/com/android/internal/os/WrapperInit.java
new file mode 100644
index 000000000000..8bbcf7aad485
--- /dev/null
+++ b/core/java/com/android/internal/os/WrapperInit.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2011 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;
+
+import android.os.Process;
+import android.util.Slog;
+
+import java.io.DataOutputStream;
+import java.io.FileDescriptor;
+import java.io.FileOutputStream;
+import java.io.IOException;
+
+import dalvik.system.Zygote;
+
+/**
+ * Startup class for the wrapper process.
+ * @hide
+ */
+public class WrapperInit {
+    private final static String TAG = "AndroidRuntime";
+
+    /**
+     * Class not instantiable.
+     */
+    private WrapperInit() {
+    }
+
+    /**
+     * The main function called when starting a runtime application through a
+     * wrapper process instead of by forking Zygote.
+     *
+     * The first argument specifies the file descriptor for a pipe that should receive
+     * the pid of this process, or 0 if none.  The remaining arguments are passed to
+     * the runtime.
+     *
+     * @param args The command-line arguments.
+     */
+    public static void main(String[] args) {
+        try {
+            // Tell the Zygote what our actual PID is (since it only knows about the
+            // wrapper that it directly forked).
+            int fdNum = Integer.parseInt(args[0], 10);
+            if (fdNum != 0) {
+                try {
+                    FileDescriptor fd = ZygoteInit.createFileDescriptor(fdNum);
+                    DataOutputStream os = new DataOutputStream(new FileOutputStream(fd));
+                    os.writeInt(Process.myPid());
+                    os.close();
+                    ZygoteInit.closeDescriptorQuietly(fd);
+                } catch (IOException ex) {
+                    Slog.d(TAG, "Could not write pid of wrapped process to Zygote pipe.", ex);
+                }
+            }
+
+            // Mimic Zygote preloading.
+            ZygoteInit.preload();
+
+            // Launch the application.
+            String[] runtimeArgs = new String[args.length - 1];
+            System.arraycopy(args, 1, runtimeArgs, 0, runtimeArgs.length);
+            RuntimeInit.wrapperInit(runtimeArgs);
+        } catch (ZygoteInit.MethodAndArgsCaller caller) {
+            caller.run();
+        }
+    }
+
+    /**
+     * Executes a runtime application with a wrapper command.
+     * This method never returns.
+     *
+     * @param invokeWith The wrapper command.
+     * @param niceName The nice name for the application, or null if none.
+     * @param pipeFd The pipe to which the application's pid should be written, or null if none.
+     * @param args Arguments for {@link RuntimeInit.main}.
+     */
+    public static void execApplication(String invokeWith, String niceName,
+            FileDescriptor pipeFd, String[] args) {
+        StringBuilder command = new StringBuilder(invokeWith);
+        command.append(" /system/bin/app_process /system/bin --application");
+        if (niceName != null) {
+            command.append(" '--nice-name=").append(niceName).append("'");
+        }
+        command.append(" com.android.internal.os.WrapperInit ");
+        command.append(pipeFd != null ? ZygoteInit.getFDFromFileDescriptor(pipeFd) : 0);
+        Zygote.appendQuotedShellArgs(command, args);
+        Zygote.execShell(command.toString());
+    }
+
+    /**
+     * Executes a standalone application with a wrapper command.
+     * This method never returns.
+     *
+     * @param invokeWith The wrapper command.
+     * @param classPath The class path.
+     * @param className The class name to invoke.
+     * @param args Arguments for the main() method of the specified class.
+     */
+    public static void execStandalone(String invokeWith, String classPath, String className,
+            String[] args) {
+        StringBuilder command = new StringBuilder(invokeWith);
+        command.append(" /system/bin/dalvikvm -classpath '").append(classPath);
+        command.append("' ").append(className);
+        Zygote.appendQuotedShellArgs(command, args);
+        Zygote.execShell(command.toString());
+    }
+}
diff --git a/core/java/com/android/internal/os/ZygoteConnection.java b/core/java/com/android/internal/os/ZygoteConnection.java
index c473fd2a5e11..f5321b51de98 100644
--- a/core/java/com/android/internal/os/ZygoteConnection.java
+++ b/core/java/com/android/internal/os/ZygoteConnection.java
@@ -26,8 +26,10 @@ import dalvik.system.PathClassLoader;
 import dalvik.system.Zygote;
 
 import java.io.BufferedReader;
+import java.io.DataInputStream;
 import java.io.DataOutputStream;
 import java.io.FileDescriptor;
+import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
@@ -193,15 +195,20 @@ class ZygoteConnection {
                     new FileOutputStream(descriptors[2]));
         }
 
-        int pid;
+        int pid = -1;
+        FileDescriptor childPipeFd = null;
+        FileDescriptor serverPipeFd = null;
 
         try {
             parsedArgs = new Arguments(args);
 
             applyUidSecurityPolicy(parsedArgs, peer);
-            applyDebuggerSecurityPolicy(parsedArgs);
             applyRlimitSecurityPolicy(parsedArgs, peer);
             applyCapabilitiesSecurityPolicy(parsedArgs, peer);
+            applyInvokeWithSecurityPolicy(parsedArgs, peer);
+
+            applyDebuggerSystemProperty(parsedArgs);
+            applyInvokeWithSystemProperty(parsedArgs);
 
             int[][] rlimits = null;
 
@@ -209,25 +216,44 @@ class ZygoteConnection {
                 rlimits = parsedArgs.rlimits.toArray(intArray2d);
             }
 
+            if (parsedArgs.runtimeInit && parsedArgs.invokeWith != null) {
+                FileDescriptor[] pipeFds = new FileDescriptor[2];
+                ZygoteInit.pipe(pipeFds);
+                childPipeFd = pipeFds[1];
+                serverPipeFd = pipeFds[0];
+                ZygoteInit.setCloseOnExec(serverPipeFd, true);
+            }
+
             pid = Zygote.forkAndSpecialize(parsedArgs.uid, parsedArgs.gid,
                     parsedArgs.gids, parsedArgs.debugFlags, rlimits);
+        } catch (IOException ex) {
+            logAndPrintError(newStderr, "Exception creating pipe", ex);
         } catch (IllegalArgumentException ex) {
-            logAndPrintError (newStderr, "Invalid zygote arguments", ex);
-            pid = -1;
+            logAndPrintError(newStderr, "Invalid zygote arguments", ex);
         } catch (ZygoteSecurityException ex) {
             logAndPrintError(newStderr,
                     "Zygote security policy prevents request: ", ex);
-            pid = -1;
         }
 
-        if (pid == 0) {
-            // in child
-            handleChildProc(parsedArgs, descriptors, newStderr);
-            // should never happen
-            return true;
-        } else { /* pid != 0 */
-            // in parent...pid of < 0 means failure
-            return handleParentProc(pid, descriptors, parsedArgs);
+        try {
+            if (pid == 0) {
+                // in child
+                ZygoteInit.closeDescriptorQuietly(serverPipeFd);
+                serverPipeFd = null;
+                handleChildProc(parsedArgs, descriptors, childPipeFd, newStderr);
+
+                // should never get here, the child is expected to either
+                // throw ZygoteInit.MethodAndArgsCaller or exec().
+                return true;
+            } else {
+                // in parent...pid of < 0 means failure
+                ZygoteInit.closeDescriptorQuietly(childPipeFd);
+                childPipeFd = null;
+                return handleParentProc(pid, descriptors, serverPipeFd, parsedArgs);
+            }
+        } finally {
+            ZygoteInit.closeDescriptorQuietly(childPipeFd);
+            ZygoteInit.closeDescriptorQuietly(serverPipeFd);
         }
     }
 
@@ -244,8 +270,8 @@ class ZygoteConnection {
     }
 
     /**
-     * Handles argument parsing for args related to the zygote spawner.<p>
-
+     * Handles argument parsing for args related to the zygote spawner.
+     *
      * Current recognized args:
      * <ul>
      *   <li> --setuid=<i>uid of child process, defaults to 0</i>
@@ -274,6 +300,7 @@ class ZygoteConnection {
      * be handed off to com.android.internal.os.RuntimeInit, rather than
      * processed directly
      * Android runtime startup (eg, Binder initialization) is also eschewed.
+     *   <li> --nice-name=<i>nice name to appear in ps</i>
      *   <li> If <code>--runtime-init</code> is present:
      *      [--] &lt;args for RuntimeInit &gt;
      *   <li> If <code>--runtime-init</code> is absent:
@@ -307,6 +334,9 @@ class ZygoteConnection {
         /** from --runtime-init */
         boolean runtimeInit;
 
+        /** from --nice-name */
+        String niceName;
+
         /** from --capabilities */
         boolean capabilitiesSpecified;
         long permittedCapabilities;
@@ -315,6 +345,9 @@ class ZygoteConnection {
         /** from all --rlimit=r,c,m */
         ArrayList<int[]> rlimits;
 
+        /** from --invoke-with */
+        String invokeWith;
+
         /**
          * Any args after and including the first non-option arg
          * (or after a '--')
@@ -438,6 +471,23 @@ class ZygoteConnection {
                     for (int i = params.length - 1; i >= 0 ; i--) {
                         gids[i] = Integer.parseInt(params[i]);
                     }
+                } else if (arg.equals("--invoke-with")) {
+                    if (invokeWith != null) {
+                        throw new IllegalArgumentException(
+                                "Duplicate arg specified");
+                    }
+                    try {
+                        invokeWith = args[++curArg];
+                    } catch (IndexOutOfBoundsException ex) {
+                        throw new IllegalArgumentException(
+                                "--invoke-with requires argument");
+                    }
+                } else if (arg.startsWith("--nice-name=")) {
+                    if (niceName != null) {
+                        throw new IllegalArgumentException(
+                                "Duplicate arg specified");
+                    }
+                    niceName = arg.substring(arg.indexOf('=') + 1);
                 } else {
                     break;
                 }
@@ -567,14 +617,15 @@ class ZygoteConnection {
 
 
     /**
-     * Applies debugger security policy.
+     * Applies debugger system properties to the zygote arguments.
+     *
      * If "ro.debuggable" is "1", all apps are debuggable. Otherwise,
      * the debugger state is specified via the "--enable-debugger" flag
      * in the spawn request.
      *
      * @param args non-null; zygote spawner args
      */
-    private static void applyDebuggerSecurityPolicy(Arguments args) {
+    public static void applyDebuggerSystemProperty(Arguments args) {
         if ("1".equals(SystemProperties.get("ro.debuggable"))) {
             args.debugFlags |= Zygote.DEBUG_ENABLE_DEBUGGER;
         }
@@ -664,12 +715,56 @@ class ZygoteConnection {
     }
 
     /**
+     * Applies zygote security policy.
+     * Based on the credentials of the process issuing a zygote command:
+     * <ol>
+     * <li> uid 0 (root) may specify --invoke-with to launch Zygote with a
+     * wrapper command.
+     * <li> Any other uid may not specify any invoke-with argument.
+     * </ul>
+     *
+     * @param args non-null; zygote spawner arguments
+     * @param peer non-null; peer credentials
+     * @throws ZygoteSecurityException
+     */
+    private static void applyInvokeWithSecurityPolicy(Arguments args, Credentials peer)
+            throws ZygoteSecurityException {
+        int peerUid = peer.getUid();
+
+        if (args.invokeWith != null && peerUid != 0) {
+            throw new ZygoteSecurityException("Peer is not permitted to specify "
+                    + "an explicit invoke-with wrapper command");
+        }
+    }
+
+    /**
+     * Applies invoke-with system properties to the zygote arguments.
+     *
+     * @param parsedArgs non-null; zygote args
+     */
+    public static void applyInvokeWithSystemProperty(Arguments args) {
+        if (args.invokeWith == null && args.niceName != null) {
+            if (args.niceName != null) {
+                String property = "wrap." + args.niceName;
+                if (property.length() > 31) {
+                    property = property.substring(0, 31);
+                }
+                args.invokeWith = SystemProperties.get(property);
+                if (args.invokeWith != null && args.invokeWith.length() == 0) {
+                    args.invokeWith = null;
+                }
+            }
+        }
+    }
+
+    /**
      * Handles post-fork setup of child proc, closing sockets as appropriate,
      * reopen stdio as appropriate, and ultimately throwing MethodAndArgsCaller
      * if successful or returning if failed.
      *
      * @param parsedArgs non-null; zygote args
      * @param descriptors null-ok; new file descriptors for stdio if available.
+     * @param pipeFd null-ok; pipe for communication back to Zygote.
      * @param newStderr null-ok; stream to use for stderr until stdio
      * is reopened.
      *
@@ -677,7 +772,7 @@ class ZygoteConnection {
      * trampoline to code that invokes static main.
      */
     private void handleChildProc(Arguments parsedArgs,
-            FileDescriptor[] descriptors, PrintStream newStderr)
+            FileDescriptor[] descriptors, FileDescriptor pipeFd, PrintStream newStderr)
             throws ZygoteInit.MethodAndArgsCaller {
 
         /*
@@ -704,7 +799,7 @@ class ZygoteConnection {
                         descriptors[1], descriptors[2]);
 
                 for (FileDescriptor fd: descriptors) {
-                    ZygoteInit.closeDescriptor(fd);
+                    ZygoteInit.closeDescriptorQuietly(fd);
                 }
                 newStderr = System.err;
             } catch (IOException ex) {
@@ -712,37 +807,48 @@ class ZygoteConnection {
             }
         }
 
-        if (parsedArgs.runtimeInit) {
-            RuntimeInit.zygoteInit(parsedArgs.remainingArgs);
-        } else {
-            ClassLoader cloader;
+        if (parsedArgs.niceName != null) {
+            Process.setArgV0(parsedArgs.niceName);
+        }
 
-            if (parsedArgs.classpath != null) {
-                cloader
-                    = new PathClassLoader(parsedArgs.classpath,
-                    ClassLoader.getSystemClassLoader());
+        if (parsedArgs.runtimeInit) {
+            if (parsedArgs.invokeWith != null) {
+                WrapperInit.execApplication(parsedArgs.invokeWith,
+                        parsedArgs.niceName, pipeFd, parsedArgs.remainingArgs);
             } else {
-                cloader = ClassLoader.getSystemClassLoader();
+                RuntimeInit.zygoteInit(parsedArgs.remainingArgs);
             }
-
+        } else {
             String className;
             try {
                 className = parsedArgs.remainingArgs[0];
             } catch (ArrayIndexOutOfBoundsException ex) {
-                logAndPrintError (newStderr,
+                logAndPrintError(newStderr,
                         "Missing required class name argument", null);
                 return;
             }
-            String[] mainArgs
-                    = new String[parsedArgs.remainingArgs.length - 1];
 
+            String[] mainArgs = new String[parsedArgs.remainingArgs.length - 1];
             System.arraycopy(parsedArgs.remainingArgs, 1,
                     mainArgs, 0, mainArgs.length);
 
-            try {
-                ZygoteInit.invokeStaticMain(cloader, className, mainArgs);
-            } catch (RuntimeException ex) {
-                logAndPrintError (newStderr, "Error starting. ", ex);
+            if (parsedArgs.invokeWith != null) {
+                WrapperInit.execStandalone(parsedArgs.invokeWith,
+                        parsedArgs.classpath, className, mainArgs);
+            } else {
+                ClassLoader cloader;
+                if (parsedArgs.classpath != null) {
+                    cloader = new PathClassLoader(parsedArgs.classpath,
+                            ClassLoader.getSystemClassLoader());
+                } else {
+                    cloader = ClassLoader.getSystemClassLoader();
+                }
+
+                try {
+                    ZygoteInit.invokeStaticMain(cloader, className, mainArgs);
+                } catch (RuntimeException ex) {
+                    logAndPrintError(newStderr, "Error starting.", ex);
+                }
             }
         }
     }
@@ -754,40 +860,61 @@ class ZygoteConnection {
      * if &lt; 0;
      * @param descriptors null-ok; file descriptors for child's new stdio if
      * specified.
+     * @param pipeFd null-ok; pipe for communication with child.
      * @param parsedArgs non-null; zygote args
      * @return true for "exit command loop" and false for "continue command
      * loop"
      */
     private boolean handleParentProc(int pid,
-            FileDescriptor[] descriptors, Arguments parsedArgs) {
+            FileDescriptor[] descriptors, FileDescriptor pipeFd, Arguments parsedArgs) {
+
+        if (pid > 0) {
+            setChildPgid(pid);
+        }
+
+        if (descriptors != null) {
+            for (FileDescriptor fd: descriptors) {
+                ZygoteInit.closeDescriptorQuietly(fd);
+            }
+        }
 
-        if(pid > 0) {
-            // Try to move the new child into the peer's process group.
+        boolean usingWrapper = false;
+        if (pipeFd != null && pid > 0) {
+            DataInputStream is = new DataInputStream(new FileInputStream(pipeFd));
+            int innerPid = -1;
             try {
-                ZygoteInit.setpgid(pid, ZygoteInit.getpgid(peer.getPid()));
+                innerPid = is.readInt();
             } catch (IOException ex) {
-                // This exception is expected in the case where
-                // the peer is not in our session
-                // TODO get rid of this log message in the case where
-                // getsid(0) != getsid(peer.getPid())
-                Log.i(TAG, "Zygote: setpgid failed. This is "
-                    + "normal if peer is not in our session");
+                Log.w(TAG, "Error reading pid from wrapped process, child may have died", ex);
+            } finally {
+                try {
+                    is.close();
+                } catch (IOException ex) {
+                }
             }
-        }
 
-        try {
-            if (descriptors != null) {
-                for (FileDescriptor fd: descriptors) {
-                    ZygoteInit.closeDescriptor(fd);
+            // Ensure that the pid reported by the wrapped process is either the
+            // child process that we forked, or a descendant of it.
+            if (innerPid > 0) {
+                int parentPid = innerPid;
+                while (parentPid > 0 && parentPid != pid) {
+                    parentPid = Process.getParentPid(parentPid);
+                }
+                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
+                            + " innerPid=" + innerPid);
                 }
             }
-        } catch (IOException ex) {
-            Log.e(TAG, "Error closing passed descriptors in "
-                    + "parent process", ex);
         }
 
         try {
             mSocketOutStream.writeInt(pid);
+            mSocketOutStream.writeBoolean(usingWrapper);
         } catch (IOException ex) {
             Log.e(TAG, "Error reading from command socket", ex);
             return true;
@@ -808,6 +935,20 @@ class ZygoteConnection {
         return false;
     }
 
+    private void setChildPgid(int pid) {
+        // Try to move the new child into the peer's process group.
+        try {
+            ZygoteInit.setpgid(pid, ZygoteInit.getpgid(peer.getPid()));
+        } catch (IOException ex) {
+            // This exception is expected in the case where
+            // the peer is not in our session
+            // TODO get rid of this log message in the case where
+            // getsid(0) != getsid(peer.getPid())
+            Log.i(TAG, "Zygote: setpgid failed. This is "
+                + "normal if peer is not in our session");
+        }
+    }
+
     /**
      * Logs an error message and prints it to the specified stream, if
      * provided
diff --git a/core/java/com/android/internal/os/ZygoteInit.java b/core/java/com/android/internal/os/ZygoteInit.java
index 060f858c42c2..958bd7a5f87e 100644
--- a/core/java/com/android/internal/os/ZygoteInit.java
+++ b/core/java/com/android/internal/os/ZygoteInit.java
@@ -22,6 +22,8 @@ import android.content.res.TypedArray;
 import android.graphics.drawable.Drawable;
 import android.net.LocalServerSocket;
 import android.os.Debug;
+import android.os.FileUtils;
+import android.os.Process;
 import android.os.SystemClock;
 import android.os.SystemProperties;
 import android.util.Config;
@@ -67,7 +69,7 @@ public class ZygoteInit {
     private static final int PRELOAD_GC_THRESHOLD = 50000;
 
     public static final String USAGE_STRING =
-            " <\"true\"|\"false\" for startSystemServer>";
+            " <\"start-system-server\"|\"\" for startSystemServer>";
 
     private static LocalServerSocket sServerSocket;
 
@@ -245,6 +247,11 @@ public class ZygoteInit {
         }
     }
 
+    static void preload() {
+        preloadClasses();
+        preloadResources();
+    }
+
     /**
      * Performs Zygote process initialization. Loads and initializes
      * commonly used classes.
@@ -494,11 +501,20 @@ public class ZygoteInit {
 
         closeServerSocket();
 
-        /*
-         * Pass the remaining arguments to SystemServer.
-         * "--nice-name=system_server com.android.server.SystemServer"
-         */
-        RuntimeInit.zygoteInit(parsedArgs.remainingArgs);
+        if (parsedArgs.niceName != null) {
+            Process.setArgV0(parsedArgs.niceName);
+        }
+
+        if (parsedArgs.invokeWith != null) {
+            WrapperInit.execApplication(parsedArgs.invokeWith,
+                    parsedArgs.niceName, null, parsedArgs.remainingArgs);
+        } else {
+            /*
+             * Pass the remaining arguments to SystemServer.
+             */
+            RuntimeInit.zygoteInit(parsedArgs.remainingArgs);
+        }
+
         /* should never reach here */
     }
 
@@ -523,20 +539,13 @@ public class ZygoteInit {
 
         try {
             parsedArgs = new ZygoteConnection.Arguments(args);
-
-            /*
-             * Enable debugging of the system process if *either* the command line flags
-             * indicate it should be debuggable or the ro.debuggable system property
-             * is set to "1"
-             */
-            int debugFlags = parsedArgs.debugFlags;
-            if ("1".equals(SystemProperties.get("ro.debuggable")))
-                debugFlags |= Zygote.DEBUG_ENABLE_DEBUGGER;
+            ZygoteConnection.applyDebuggerSystemProperty(parsedArgs);
+            ZygoteConnection.applyInvokeWithSystemProperty(parsedArgs);
 
             /* Request to fork the system server process */
             pid = Zygote.forkSystemServer(
                     parsedArgs.uid, parsedArgs.gid,
-                    parsedArgs.gids, debugFlags, null,
+                    parsedArgs.gids, parsedArgs.debugFlags, null,
                     parsedArgs.permittedCapabilities,
                     parsedArgs.effectiveCapabilities);
         } catch (IllegalArgumentException ex) {
@@ -561,9 +570,7 @@ public class ZygoteInit {
             registerZygoteSocket();
             EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_START,
                 SystemClock.uptimeMillis());
-            preloadClasses();
-            //cacheRegisterMaps();
-            preloadResources();
+            preload();
             EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_END,
                 SystemClock.uptimeMillis());
 
@@ -578,9 +585,9 @@ public class ZygoteInit {
                 throw new RuntimeException(argv[0] + USAGE_STRING);
             }
 
-            if (argv[1].equals("true")) {
+            if (argv[1].equals("start-system-server")) {
                 startSystemServer();
-            } else if (!argv[1].equals("false")) {
+            } else if (!argv[1].equals("")) {
                 throw new RuntimeException(argv[0] + USAGE_STRING);
             }
 
@@ -760,6 +767,13 @@ public class ZygoteInit {
     static native void closeDescriptor(FileDescriptor fd)
             throws IOException;
 
+    static void closeDescriptorQuietly(FileDescriptor fd) {
+        try {
+            closeDescriptor(fd);
+        } catch (IOException e) {
+        }
+    }
+
     /**
      * Toggles the close-on-exec flag for the specified file descriptor.
      *
@@ -811,6 +825,21 @@ public class ZygoteInit {
             throws IOException;
 
     /**
+     * Gets the integer value of a file descriptor.
+     *
+     * @param fd non-null; file descriptor
+     * @return integer OS file descriptor
+     */
+    static native int getFDFromFileDescriptor(FileDescriptor fd);
+
+    /**
+     * Creates a pipe.
+     *
+     * @param outFds non-null; an array to hold two file descriptors, initially null
+     */
+    static native void pipe(FileDescriptor[] outFds) throws IOException;
+
+    /**
      * Class not instantiable.
      */
     private ZygoteInit() {