Merge "Richer ParcelFileDescriptor close events." into klp-dev

7 files changed, 657 insertions, 276 deletions

diff --git a/api/current.txt b/api/current.txt
index 2970f2b..f912a0b 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -18113,8 +18113,14 @@ package android.os {
   public class ParcelFileDescriptor implements java.io.Closeable android.os.Parcelable {
     ctor public ParcelFileDescriptor(android.os.ParcelFileDescriptor);
     method public static android.os.ParcelFileDescriptor adoptFd(int);
+    method public boolean canDetectErrors();
+    method public void checkError(boolean) throws java.io.IOException;
     method public void close() throws java.io.IOException;
+    method public void closeWithError(java.lang.String) throws java.io.IOException;
     method public static android.os.ParcelFileDescriptor[] createPipe() throws java.io.IOException;
+    method public static android.os.ParcelFileDescriptor[] createReliablePipe() throws java.io.IOException;
+    method public static android.os.ParcelFileDescriptor[] createReliableSocketPair() throws java.io.IOException;
+    method public static android.os.ParcelFileDescriptor[] createSocketPair() throws java.io.IOException;
     method public int describeContents();
     method public int detachFd();
     method public static android.os.ParcelFileDescriptor dup(java.io.FileDescriptor) throws java.io.IOException;
@@ -18126,6 +18132,7 @@ package android.os {
     method public java.io.FileDescriptor getFileDescriptor();
     method public long getStatSize();
     method public static android.os.ParcelFileDescriptor open(java.io.File, int) throws java.io.FileNotFoundException;
+    method public static android.os.ParcelFileDescriptor open(java.io.File, int, android.os.Handler, android.os.ParcelFileDescriptor.OnCloseListener) throws java.io.IOException;
     method public void writeToParcel(android.os.Parcel, int);
     field public static final android.os.Parcelable.Creator CREATOR;
     field public static final int MODE_APPEND = 33554432; // 0x2000000
@@ -18133,8 +18140,8 @@ package android.os {
     field public static final int MODE_READ_ONLY = 268435456; // 0x10000000
     field public static final int MODE_READ_WRITE = 805306368; // 0x30000000
     field public static final int MODE_TRUNCATE = 67108864; // 0x4000000
-    field public static final int MODE_WORLD_READABLE = 1; // 0x1
-    field public static final int MODE_WORLD_WRITEABLE = 2; // 0x2
+    field public static final deprecated int MODE_WORLD_READABLE = 1; // 0x1
+    field public static final deprecated int MODE_WORLD_WRITEABLE = 2; // 0x2
     field public static final int MODE_WRITE_ONLY = 536870912; // 0x20000000
   }
 
@@ -18146,6 +18153,10 @@ package android.os {
     ctor public ParcelFileDescriptor.AutoCloseOutputStream(android.os.ParcelFileDescriptor);
   }
 
+  public static abstract interface ParcelFileDescriptor.OnCloseListener {
+    method public abstract void onClose(java.io.IOException, boolean);
+  }
+
   public class ParcelFormatException extends java.lang.RuntimeException {
     ctor public ParcelFormatException();
     ctor public ParcelFormatException(java.lang.String);
diff --git a/core/java/android/content/ContentResolver.java b/core/java/android/content/ContentResolver.java
index 45fed2d..5cabfee 100644
--- a/core/java/android/content/ContentResolver.java
+++ b/core/java/android/content/ContentResolver.java
@@ -2060,7 +2060,7 @@ public abstract class ContentResolver {
 
     private final class ParcelFileDescriptorInner extends ParcelFileDescriptor {
         private final IContentProvider mContentProvider;
-        private boolean mReleaseProviderFlag = false;
+        private boolean mProviderReleased;
 
         ParcelFileDescriptorInner(ParcelFileDescriptor pfd, IContentProvider icp) {
             super(pfd);
@@ -2069,17 +2069,10 @@ public abstract class ContentResolver {
 
         @Override
         public void close() throws IOException {
-            if(!mReleaseProviderFlag) {
-                super.close();
+            super.close();
+            if (!mProviderReleased) {
                 ContentResolver.this.releaseProvider(mContentProvider);
-                mReleaseProviderFlag = true;
-            }
-        }
-
-        @Override
-        protected void finalize() throws Throwable {
-            if (!mReleaseProviderFlag) {
-                close();
+                mProviderReleased = true;
             }
         }
     }
diff --git a/core/java/android/os/Parcel.java b/core/java/android/os/Parcel.java
index 12f7915..46b0150 100644
--- a/core/java/android/os/Parcel.java
+++ b/core/java/android/os/Parcel.java
@@ -1520,6 +1520,11 @@ public final class Parcel {
         return fd != null ? new ParcelFileDescriptor(fd) : null;
     }
 
+    /** {@hide} */
+    public final FileDescriptor readRawFileDescriptor() {
+        return nativeReadFileDescriptor(mNativePtr);
+    }
+
     /*package*/ static native FileDescriptor openFileDescriptor(String file,
             int mode) throws FileNotFoundException;
     /*package*/ static native FileDescriptor dupFileDescriptor(FileDescriptor orig)
diff --git a/core/java/android/os/ParcelFileDescriptor.java b/core/java/android/os/ParcelFileDescriptor.java
index 3de362c..579971d 100644
--- a/core/java/android/os/ParcelFileDescriptor.java
+++ b/core/java/android/os/ParcelFileDescriptor.java
@@ -16,8 +16,25 @@
 
 package android.os;
 
+import static libcore.io.OsConstants.AF_UNIX;
+import static libcore.io.OsConstants.SEEK_SET;
+import static libcore.io.OsConstants.SOCK_STREAM;
+import static libcore.io.OsConstants.S_ISLNK;
+import static libcore.io.OsConstants.S_ISREG;
+
+import android.content.BroadcastReceiver;
+import android.content.ContentProvider;
+import android.util.Log;
+
 import dalvik.system.CloseGuard;
 
+import libcore.io.ErrnoException;
+import libcore.io.IoUtils;
+import libcore.io.Libcore;
+import libcore.io.Memory;
+import libcore.io.OsConstants;
+import libcore.io.StructStat;
+
 import java.io.Closeable;
 import java.io.File;
 import java.io.FileDescriptor;
@@ -27,36 +44,80 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.net.DatagramSocket;
 import java.net.Socket;
+import java.nio.ByteOrder;
 
 /**
  * The FileDescriptor returned by {@link Parcel#readFileDescriptor}, allowing
  * you to close it when done with it.
  */
 public class ParcelFileDescriptor implements Parcelable, Closeable {
-    private final FileDescriptor mFileDescriptor;
+    private static final String TAG = "ParcelFileDescriptor";
+
+    private final FileDescriptor mFd;
+
+    /**
+     * Optional socket used to communicate close events, status at close, and
+     * detect remote process crashes.
+     */
+    private FileDescriptor mCommFd;
 
     /**
      * Wrapped {@link ParcelFileDescriptor}, if any. Used to avoid
-     * double-closing {@link #mFileDescriptor}.
+     * double-closing {@link #mFd}.
      */
     private final ParcelFileDescriptor mWrapped;
 
+    /**
+     * Maximum {@link #mStatusBuf} size; longer status messages will be
+     * truncated.
+     */
+    private static final int MAX_STATUS = 1024;
+
+    /**
+     * Temporary buffer used by {@link #readCommStatus(FileDescriptor, byte[])},
+     * allocated on-demand.
+     */
+    private byte[] mStatusBuf;
+
+    /**
+     * Status read by {@link #checkError(boolean)}, or null if not read yet.
+     */
+    private Status mStatus;
+
     private volatile boolean mClosed;
 
     private final CloseGuard mGuard = CloseGuard.get();
 
     /**
-     * For use with {@link #open}: if {@link #MODE_CREATE} has been supplied
-     * and this file doesn't already exist, then create the file with
-     * permissions such that any application can read it.
+     * For use with {@link #open}: if {@link #MODE_CREATE} has been supplied and
+     * this file doesn't already exist, then create the file with permissions
+     * such that any application can read it.
+     *
+     * @deprecated Creating world-readable files is very dangerous, and likely
+     *             to cause security holes in applications. It is strongly
+     *             discouraged; instead, applications should use more formal
+     *             mechanism for interactions such as {@link ContentProvider},
+     *             {@link BroadcastReceiver}, and {@link android.app.Service}.
+     *             There are no guarantees that this access mode will remain on
+     *             a file, such as when it goes through a backup and restore.
      */
+    @Deprecated
     public static final int MODE_WORLD_READABLE = 0x00000001;
 
     /**
-     * For use with {@link #open}: if {@link #MODE_CREATE} has been supplied
-     * and this file doesn't already exist, then create the file with
-     * permissions such that any application can write it.
+     * For use with {@link #open}: if {@link #MODE_CREATE} has been supplied and
+     * this file doesn't already exist, then create the file with permissions
+     * such that any application can write it.
+     *
+     * @deprecated Creating world-writable files is very dangerous, and likely
+     *             to cause security holes in applications. It is strongly
+     *             discouraged; instead, applications should use more formal
+     *             mechanism for interactions such as {@link ContentProvider},
+     *             {@link BroadcastReceiver}, and {@link android.app.Service}.
+     *             There are no guarantees that this access mode will remain on
+     *             a file, such as when it goes through a backup and restore.
      */
+    @Deprecated
     public static final int MODE_WORLD_WRITEABLE = 0x00000002;
 
     /**
@@ -90,32 +151,102 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
     public static final int MODE_APPEND = 0x02000000;
 
     /**
+     * Create a new ParcelFileDescriptor wrapped around another descriptor. By
+     * default all method calls are delegated to the wrapped descriptor.
+     */
+    public ParcelFileDescriptor(ParcelFileDescriptor wrapped) {
+        // We keep a strong reference to the wrapped PFD, and rely on its
+        // finalizer to trigger CloseGuard. All calls are delegated to wrapper.
+        mWrapped = wrapped;
+        mFd = null;
+        mCommFd = null;
+        mClosed = true;
+    }
+
+    /** {@hide} */
+    public ParcelFileDescriptor(FileDescriptor fd) {
+        this(fd, null);
+    }
+
+    /** {@hide} */
+    public ParcelFileDescriptor(FileDescriptor fd, FileDescriptor commChannel) {
+        if (fd == null) {
+            throw new NullPointerException("FileDescriptor must not be null");
+        }
+        mWrapped = null;
+        mFd = fd;
+        mCommFd = commChannel;
+        mGuard.open("close");
+    }
+
+    /**
      * Create a new ParcelFileDescriptor accessing a given file.
      *
      * @param file The file to be opened.
      * @param mode The desired access mode, must be one of
-     * {@link #MODE_READ_ONLY}, {@link #MODE_WRITE_ONLY}, or
-     * {@link #MODE_READ_WRITE}; may also be any combination of
-     * {@link #MODE_CREATE}, {@link #MODE_TRUNCATE},
-     * {@link #MODE_WORLD_READABLE}, and {@link #MODE_WORLD_WRITEABLE}.
-     *
-     * @return Returns a new ParcelFileDescriptor pointing to the given
-     * file.
+     *            {@link #MODE_READ_ONLY}, {@link #MODE_WRITE_ONLY}, or
+     *            {@link #MODE_READ_WRITE}; may also be any combination of
+     *            {@link #MODE_CREATE}, {@link #MODE_TRUNCATE},
+     *            {@link #MODE_WORLD_READABLE}, and
+     *            {@link #MODE_WORLD_WRITEABLE}.
+     * @return a new ParcelFileDescriptor pointing to the given file.
+     * @throws FileNotFoundException if the given file does not exist or can not
+     *             be opened with the requested mode.
+     */
+    public static ParcelFileDescriptor open(File file, int mode) throws FileNotFoundException {
+        final FileDescriptor fd = openInternal(file, mode);
+        if (fd == null) return null;
+
+        return new ParcelFileDescriptor(fd);
+    }
+
+    /**
+     * Create a new ParcelFileDescriptor accessing a given file.
      *
-     * @throws FileNotFoundException Throws FileNotFoundException if the given
-     * file does not exist or can not be opened with the requested mode.
+     * @param file The file to be opened.
+     * @param mode The desired access mode, must be one of
+     *            {@link #MODE_READ_ONLY}, {@link #MODE_WRITE_ONLY}, or
+     *            {@link #MODE_READ_WRITE}; may also be any combination of
+     *            {@link #MODE_CREATE}, {@link #MODE_TRUNCATE},
+     *            {@link #MODE_WORLD_READABLE}, and
+     *            {@link #MODE_WORLD_WRITEABLE}.
+     * @param handler to call listener from; must not be null.
+     * @param listener to be invoked when the returned descriptor has been
+     *            closed; must not be null.
+     * @return a new ParcelFileDescriptor pointing to the given file.
+     * @throws FileNotFoundException if the given file does not exist or can not
+     *             be opened with the requested mode.
      */
-    public static ParcelFileDescriptor open(File file, int mode)
-            throws FileNotFoundException {
-        String path = file.getPath();
+    public static ParcelFileDescriptor open(
+            File file, int mode, Handler handler, OnCloseListener listener) throws IOException {
+        if (handler == null) {
+            throw new IllegalArgumentException("Handler must not be null");
+        }
+        if (listener == null) {
+            throw new IllegalArgumentException("Listener must not be null");
+        }
+
+        final FileDescriptor fd = openInternal(file, mode);
+        if (fd == null) return null;
+
+        final FileDescriptor[] comm = createCommSocketPair(true);
+        final ParcelFileDescriptor pfd = new ParcelFileDescriptor(fd, comm[0]);
+
+        // Kick off thread to watch for status updates
+        final ListenerBridge bridge = new ListenerBridge(comm[1], handler.getLooper(), listener);
+        bridge.start();
+
+        return pfd;
+    }
 
-        if ((mode&MODE_READ_WRITE) == 0) {
+    private static FileDescriptor openInternal(File file, int mode) throws FileNotFoundException {
+        if ((mode & MODE_READ_WRITE) == 0) {
             throw new IllegalArgumentException(
                     "Must specify MODE_READ_ONLY, MODE_WRITE_ONLY, or MODE_READ_WRITE");
         }
 
-        FileDescriptor fd = Parcel.openFileDescriptor(path, mode);
-        return fd != null ? new ParcelFileDescriptor(fd) : null;
+        final String path = file.getPath();
+        return Parcel.openFileDescriptor(path, mode);
     }
 
     /**
@@ -125,8 +256,12 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      * original file descriptor.
      */
     public static ParcelFileDescriptor dup(FileDescriptor orig) throws IOException {
-        FileDescriptor fd = Parcel.dupFileDescriptor(orig);
-        return fd != null ? new ParcelFileDescriptor(fd) : null;
+        try {
+            final FileDescriptor fd = Libcore.os.dup(orig);
+            return new ParcelFileDescriptor(fd);
+        } catch (ErrnoException e) {
+            throw e.rethrowAsIOException();
+        }
     }
 
     /**
@@ -136,7 +271,11 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      * original file descriptor.
      */
     public ParcelFileDescriptor dup() throws IOException {
-        return dup(getFileDescriptor());
+        if (mWrapped != null) {
+            return mWrapped.dup();
+        } else {
+            return dup(getFileDescriptor());
+        }
     }
 
     /**
@@ -150,12 +289,16 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      * for a dup of the given fd.
      */
     public static ParcelFileDescriptor fromFd(int fd) throws IOException {
-        FileDescriptor fdesc = getFileDescriptorFromFd(fd);
-        return new ParcelFileDescriptor(fdesc);
-    }
+        final FileDescriptor original = new FileDescriptor();
+        original.setInt$(fd);
 
-    // Extracts the file descriptor from the specified socket and returns it untouched
-    private static native FileDescriptor getFileDescriptorFromFd(int fd) throws IOException;
+        try {
+            final FileDescriptor dup = Libcore.os.dup(original);
+            return new ParcelFileDescriptor(dup);
+        } catch (ErrnoException e) {
+            throw e.rethrowAsIOException();
+        }
+    }
 
     /**
      * Take ownership of a raw native fd in to a new ParcelFileDescriptor.
@@ -168,13 +311,12 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      * for the given fd.
      */
     public static ParcelFileDescriptor adoptFd(int fd) {
-        FileDescriptor fdesc = getFileDescriptorFromFdNoDup(fd);
+        final FileDescriptor fdesc = new FileDescriptor();
+        fdesc.setInt$(fd);
+
         return new ParcelFileDescriptor(fdesc);
     }
 
-    // Extracts the file descriptor from the specified socket and returns it untouched
-    private static native FileDescriptor getFileDescriptorFromFdNoDup(int fd);
-
     /**
      * Create a new ParcelFileDescriptor from the specified Socket.  The new
      * ParcelFileDescriptor holds a dup of the original FileDescriptor in
@@ -212,15 +354,90 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      * is the write side.
      */
     public static ParcelFileDescriptor[] createPipe() throws IOException {
-        FileDescriptor[] fds = new FileDescriptor[2];
-        createPipeNative(fds);
-        ParcelFileDescriptor[] pfds = new ParcelFileDescriptor[2];
-        pfds[0] = new ParcelFileDescriptor(fds[0]);
-        pfds[1] = new ParcelFileDescriptor(fds[1]);
-        return pfds;
+        try {
+            final FileDescriptor[] fds = Libcore.os.pipe();
+            return new ParcelFileDescriptor[] {
+                    new ParcelFileDescriptor(fds[0]),
+                    new ParcelFileDescriptor(fds[1]) };
+        } catch (ErrnoException e) {
+            throw e.rethrowAsIOException();
+        }
+    }
+
+    /**
+     * Create two ParcelFileDescriptors structured as a data pipe. The first
+     * ParcelFileDescriptor in the returned array is the read side; the second
+     * is the write side.
+     * <p>
+     * The write end has the ability to deliver an error message through
+     * {@link #closeWithError(String)} which can be handled by the read end
+     * calling {@link #checkError(boolean)}, usually after detecting an EOF.
+     * This can also be used to detect remote crashes.
+     */
+    public static ParcelFileDescriptor[] createReliablePipe() throws IOException {
+        try {
+            final FileDescriptor[] comm = createCommSocketPair(false);
+            final FileDescriptor[] fds = Libcore.os.pipe();
+            return new ParcelFileDescriptor[] {
+                    new ParcelFileDescriptor(fds[0], comm[0]),
+                    new ParcelFileDescriptor(fds[1], comm[1]) };
+        } catch (ErrnoException e) {
+            throw e.rethrowAsIOException();
+        }
     }
 
-    private static native void createPipeNative(FileDescriptor[] outFds) throws IOException;
+    /**
+     * Create two ParcelFileDescriptors structured as a pair of sockets
+     * connected to each other. The two sockets are indistinguishable.
+     */
+    public static ParcelFileDescriptor[] createSocketPair() throws IOException {
+        try {
+            final FileDescriptor fd0 = new FileDescriptor();
+            final FileDescriptor fd1 = new FileDescriptor();
+            Libcore.os.socketpair(AF_UNIX, SOCK_STREAM, 0, fd0, fd1);
+            return new ParcelFileDescriptor[] {
+                    new ParcelFileDescriptor(fd0),
+                    new ParcelFileDescriptor(fd1) };
+        } catch (ErrnoException e) {
+            throw e.rethrowAsIOException();
+        }
+    }
+
+    /**
+     * Create two ParcelFileDescriptors structured as a pair of sockets
+     * connected to each other. The two sockets are indistinguishable.
+     * <p>
+     * Both ends have the ability to deliver an error message through
+     * {@link #closeWithError(String)} which can be detected by the other end
+     * calling {@link #checkError(boolean)}, usually after detecting an EOF.
+     * This can also be used to detect remote crashes.
+     */
+    public static ParcelFileDescriptor[] createReliableSocketPair() throws IOException {
+        try {
+            final FileDescriptor[] comm = createCommSocketPair(false);
+            final FileDescriptor fd0 = new FileDescriptor();
+            final FileDescriptor fd1 = new FileDescriptor();
+            Libcore.os.socketpair(AF_UNIX, SOCK_STREAM, 0, fd0, fd1);
+            return new ParcelFileDescriptor[] {
+                    new ParcelFileDescriptor(fd0, comm[0]),
+                    new ParcelFileDescriptor(fd1, comm[1]) };
+        } catch (ErrnoException e) {
+            throw e.rethrowAsIOException();
+        }
+    }
+
+    private static FileDescriptor[] createCommSocketPair(boolean blocking) throws IOException {
+        try {
+            final FileDescriptor comm1 = new FileDescriptor();
+            final FileDescriptor comm2 = new FileDescriptor();
+            Libcore.os.socketpair(AF_UNIX, SOCK_STREAM, 0, comm1, comm2);
+            IoUtils.setBlocking(comm1, blocking);
+            IoUtils.setBlocking(comm2, blocking);
+            return new FileDescriptor[] { comm1, comm2 };
+        } catch (ErrnoException e) {
+            throw e.rethrowAsIOException();
+        }
+    }
 
     /**
      * @hide Please use createPipe() or ContentProvider.openPipeHelper().
@@ -250,21 +467,51 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      * @return Returns the FileDescriptor associated with this object.
      */
     public FileDescriptor getFileDescriptor() {
-        return mFileDescriptor;
+        if (mWrapped != null) {
+            return mWrapped.getFileDescriptor();
+        } else {
+            return mFd;
+        }
     }
 
     /**
-     * Return the total size of the file representing this fd, as determined
-     * by stat().  Returns -1 if the fd is not a file.
+     * Return the total size of the file representing this fd, as determined by
+     * {@code stat()}. Returns -1 if the fd is not a file.
      */
-    public native long getStatSize();
+    public long getStatSize() {
+        if (mWrapped != null) {
+            return mWrapped.getStatSize();
+        } else {
+            try {
+                final StructStat st = Libcore.os.fstat(mFd);
+                if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) {
+                    return st.st_size;
+                } else {
+                    return -1;
+                }
+            } catch (ErrnoException e) {
+                Log.w(TAG, "fstat() failed: " + e);
+                return -1;
+            }
+        }
+    }
 
     /**
      * This is needed for implementing AssetFileDescriptor.AutoCloseOutputStream,
      * and I really don't think we want it to be public.
      * @hide
      */
-    public native long seekTo(long pos);
+    public long seekTo(long pos) throws IOException {
+        if (mWrapped != null) {
+            return mWrapped.seekTo(pos);
+        } else {
+            try {
+                return Libcore.os.lseek(mFd, pos, SEEK_SET);
+            } catch (ErrnoException e) {
+                throw e.rethrowAsIOException();
+            }
+        }
+    }
 
     /**
      * Return the native fd int for this ParcelFileDescriptor.  The
@@ -272,34 +519,39 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      * through this API.
      */
     public int getFd() {
-        if (mClosed) {
-            throw new IllegalStateException("Already closed");
+        if (mWrapped != null) {
+            return mWrapped.getFd();
+        } else {
+            if (mClosed) {
+                throw new IllegalStateException("Already closed");
+            }
+            return mFd.getInt$();
         }
-        return getFdNative();
     }
 
-    private native int getFdNative();
-
     /**
-     * Return the native fd int for this ParcelFileDescriptor and detach it
-     * from the object here.  You are now responsible for closing the fd in
-     * native code.
+     * Return the native fd int for this ParcelFileDescriptor and detach it from
+     * the object here. You are now responsible for closing the fd in native
+     * code.
+     * <p>
+     * You should not detach when the original creator of the descriptor is
+     * expecting a reliable signal through {@link #close()} or
+     * {@link #closeWithError(String)}.
+     *
+     * @see #canDetectErrors()
      */
     public int detachFd() {
-        if (mClosed) {
-            throw new IllegalStateException("Already closed");
-        }
         if (mWrapped != null) {
-            int fd = mWrapped.detachFd();
-            mClosed = true;
-            mGuard.close();
+            return mWrapped.detachFd();
+        } else {
+            if (mClosed) {
+                throw new IllegalStateException("Already closed");
+            }
+            final int fd = getFd();
+            Parcel.clearFileDescriptor(mFd);
+            writeCommStatusAndClose(Status.DETACHED, null);
             return fd;
         }
-        int fd = getFd();
-        mClosed = true;
-        mGuard.close();
-        Parcel.clearFileDescriptor(mFileDescriptor);
-        return fd;
     }
 
     /**
@@ -311,16 +563,176 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      */
     @Override
     public void close() throws IOException {
-        if (mClosed) return;
-        mClosed = true;
-        mGuard.close();
-
         if (mWrapped != null) {
-            // If this is a proxy to another file descriptor, just call through to its
-            // close method.
             mWrapped.close();
         } else {
-            Parcel.closeFileDescriptor(mFileDescriptor);
+            closeWithStatus(Status.OK, null);
+        }
+    }
+
+    /**
+     * Close the ParcelFileDescriptor, informing any peer that an error occurred
+     * while processing. If the creator of this descriptor is not observing
+     * errors, it will close normally.
+     *
+     * @param msg describing the error; must not be null.
+     */
+    public void closeWithError(String msg) throws IOException {
+        if (mWrapped != null) {
+            mWrapped.closeWithError(msg);
+        } else {
+            if (msg == null) {
+                throw new IllegalArgumentException("Message must not be null");
+            }
+            closeWithStatus(Status.ERROR, msg);
+        }
+    }
+
+    private void closeWithStatus(int status, String msg) throws IOException {
+        if (mWrapped != null) {
+            mWrapped.closeWithStatus(status, msg);
+        } else {
+            if (mClosed) return;
+            mClosed = true;
+            mGuard.close();
+            // Status MUST be sent before closing actual descriptor
+            writeCommStatusAndClose(status, msg);
+            IoUtils.closeQuietly(mFd);
+        }
+    }
+
+    private byte[] getOrCreateStatusBuffer() {
+        if (mStatusBuf == null) {
+            mStatusBuf = new byte[MAX_STATUS];
+        }
+        return mStatusBuf;
+    }
+
+    private void writeCommStatusAndClose(int status, String msg) {
+        if (mCommFd == null) {
+            // Not reliable, or someone already sent status
+            if (msg != null) {
+                Log.w(TAG, "Unable to inform peer: " + msg);
+            }
+            return;
+        }
+
+        if (status == Status.DETACHED) {
+            Log.w(TAG, "Peer expected signal when closed; unable to deliver after detach");
+        }
+
+        try {
+            try {
+                if (status != Status.SILENCE) {
+                    final byte[] buf = getOrCreateStatusBuffer();
+                    int writePtr = 0;
+
+                    Memory.pokeInt(buf, writePtr, status, ByteOrder.BIG_ENDIAN);
+                    writePtr += 4;
+
+                    if (msg != null) {
+                        final byte[] rawMsg = msg.getBytes();
+                        final int len = Math.min(rawMsg.length, buf.length - writePtr);
+                        System.arraycopy(rawMsg, 0, buf, writePtr, len);
+                        writePtr += len;
+                    }
+
+                    Libcore.os.write(mCommFd, buf, 0, writePtr);
+                }
+            } catch (ErrnoException e) {
+                // Reporting status is best-effort
+                Log.w(TAG, "Failed to report status: " + e);
+            }
+
+            if (status != Status.SILENCE) {
+                // Since we're about to close, read off any remote status. It's
+                // okay to remember missing here.
+                mStatus = readCommStatus(mCommFd, getOrCreateStatusBuffer());
+            }
+
+        } finally {
+            IoUtils.closeQuietly(mCommFd);
+            mCommFd = null;
+        }
+    }
+
+    private static Status readCommStatus(FileDescriptor comm, byte[] buf) {
+        try {
+            final int n = Libcore.os.read(comm, buf, 0, buf.length);
+            if (n == 0) {
+                // EOF means they're dead
+                return new Status(Status.DEAD);
+            } else {
+                final int status = Memory.peekInt(buf, 0, ByteOrder.BIG_ENDIAN);
+                if (status == Status.ERROR) {
+                    final String msg = new String(buf, 4, n - 4);
+                    return new Status(status, msg);
+                }
+                return new Status(status);
+            }
+        } catch (ErrnoException e) {
+            if (e.errno == OsConstants.EAGAIN) {
+                // Remote is still alive, but no status written yet
+                return null;
+            } else {
+                Log.d(TAG, "Failed to read status; assuming dead: " + e);
+                return new Status(Status.DEAD);
+            }
+        }
+    }
+
+    /**
+     * Indicates if this ParcelFileDescriptor can communicate and detect remote
+     * errors/crashes.
+     *
+     * @see #checkError(boolean)
+     */
+    public boolean canDetectErrors() {
+        if (mWrapped != null) {
+            return mWrapped.canDetectErrors();
+        } else {
+            return mCommFd != null;
+        }
+    }
+
+    /**
+     * Detect and throw if the other end of a pipe or socket pair encountered an
+     * error or crashed. This allows a reader to distinguish between a valid EOF
+     * and an error/crash.
+     * <p>
+     * If this ParcelFileDescriptor is unable to detect remote errors, it will
+     * return silently.
+     *
+     * @param throwIfDetached requests that an exception be thrown if the remote
+     *            side called {@link #detachFd()}. Once detached, the remote
+     *            side is unable to communicate any errors through
+     *            {@link #closeWithError(String)}. An application may pass true
+     *            if it needs a stronger guarantee that the stream was closed
+     *            normally and was not merely detached.
+     * @see #canDetectErrors()
+     */
+    public void checkError(boolean throwIfDetached) throws IOException {
+        if (mWrapped != null) {
+            mWrapped.checkError(throwIfDetached);
+        } else {
+            if (mStatus == null) {
+                if (mCommFd == null) {
+                    Log.w(TAG, "Peer didn't provide a comm channel; unable to check for errors");
+                    return;
+                }
+
+                // Try reading status; it might be null if nothing written yet.
+                // Either way, we keep comm open to write our status later.
+                mStatus = readCommStatus(mCommFd, getOrCreateStatusBuffer());
+            }
+
+            if (mStatus == null || mStatus.status == Status.OK
+                    || (mStatus.status == Status.DETACHED && !throwIfDetached)) {
+                // No status yet, or everything is peachy!
+                return;
+            } else {
+                throw mStatus.asIOException();
+            }
         }
     }
 
@@ -330,17 +742,17 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      * ParcelFileDescriptor.close()} for you when the stream is closed.
      */
     public static class AutoCloseInputStream extends FileInputStream {
-        private final ParcelFileDescriptor mFd;
+        private final ParcelFileDescriptor mPfd;
 
-        public AutoCloseInputStream(ParcelFileDescriptor fd) {
-            super(fd.getFileDescriptor());
-            mFd = fd;
+        public AutoCloseInputStream(ParcelFileDescriptor pfd) {
+            super(pfd.getFileDescriptor());
+            mPfd = pfd;
         }
 
         @Override
         public void close() throws IOException {
             try {
-                mFd.close();
+                mPfd.close();
             } finally {
                 super.close();
             }
@@ -353,17 +765,17 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      * ParcelFileDescriptor.close()} for you when the stream is closed.
      */
     public static class AutoCloseOutputStream extends FileOutputStream {
-        private final ParcelFileDescriptor mFd;
+        private final ParcelFileDescriptor mPfd;
 
-        public AutoCloseOutputStream(ParcelFileDescriptor fd) {
-            super(fd.getFileDescriptor());
-            mFd = fd;
+        public AutoCloseOutputStream(ParcelFileDescriptor pfd) {
+            super(pfd.getFileDescriptor());
+            mPfd = pfd;
         }
 
         @Override
         public void close() throws IOException {
             try {
-                mFd.close();
+                mPfd.close();
             } finally {
                 super.close();
             }
@@ -372,7 +784,11 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
 
     @Override
     public String toString() {
-        return "{ParcelFileDescriptor: " + mFileDescriptor + "}";
+        if (mWrapped != null) {
+            return mWrapped.toString();
+        } else {
+            return "{ParcelFileDescriptor: " + mFd + "}";
+        }
     }
 
     @Override
@@ -382,32 +798,20 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
         }
         try {
             if (!mClosed) {
-                close();
+                closeWithStatus(Status.LEAKED, null);
             }
         } finally {
             super.finalize();
         }
     }
 
-    public ParcelFileDescriptor(ParcelFileDescriptor descriptor) {
-        mWrapped = descriptor;
-        mFileDescriptor = mWrapped.mFileDescriptor;
-        mGuard.open("close");
-    }
-
-    /** {@hide} */
-    public ParcelFileDescriptor(FileDescriptor descriptor) {
-        if (descriptor == null) {
-            throw new NullPointerException("descriptor must not be null");
-        }
-        mWrapped = null;
-        mFileDescriptor = descriptor;
-        mGuard.open("close");
-    }
-
     @Override
     public int describeContents() {
-        return Parcelable.CONTENTS_FILE_DESCRIPTOR;
+        if (mWrapped != null) {
+            return mWrapped.describeContents();
+        } else {
+            return Parcelable.CONTENTS_FILE_DESCRIPTOR;
+        }
     }
 
     /**
@@ -417,12 +821,22 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      */
     @Override
     public void writeToParcel(Parcel out, int flags) {
-        out.writeFileDescriptor(mFileDescriptor);
-        if ((flags&PARCELABLE_WRITE_RETURN_VALUE) != 0 && !mClosed) {
-            try {
-                close();
-            } catch (IOException e) {
-                // Empty
+        if (mWrapped != null) {
+            mWrapped.writeToParcel(out, flags);
+        } else {
+            out.writeFileDescriptor(mFd);
+            if (mCommFd != null) {
+                out.writeInt(1);
+                out.writeFileDescriptor(mCommFd);
+            } else {
+                out.writeInt(0);
+            }
+            if ((flags & PARCELABLE_WRITE_RETURN_VALUE) != 0 && !mClosed) {
+                try {
+                    // Not a real close, so emit no status
+                    closeWithStatus(Status.SILENCE, null);
+                } catch (IOException e) {
+                }
             }
         }
     }
@@ -431,7 +845,12 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
             = new Parcelable.Creator<ParcelFileDescriptor>() {
         @Override
         public ParcelFileDescriptor createFromParcel(Parcel in) {
-            return in.readFileDescriptor();
+            final FileDescriptor fd = in.readRawFileDescriptor();
+            FileDescriptor commChannel = null;
+            if (in.readInt() != 0) {
+                commChannel = in.readRawFileDescriptor();
+            }
+            return new ParcelFileDescriptor(fd, commChannel);
         }
 
         @Override
@@ -439,4 +858,111 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
             return new ParcelFileDescriptor[size];
         }
     };
+
+    /**
+     * Callback indicating that a ParcelFileDescriptor has been closed.
+     */
+    public interface OnCloseListener {
+        /**
+         * Event indicating the ParcelFileDescriptor to which this listener was
+         * attached has been closed.
+         *
+         * @param e error state, or {@code null} if closed cleanly.
+         * @param fromDetach indicates if close event was result of
+         *            {@link ParcelFileDescriptor#detachFd()}. After detach the
+         *            remote side may continue reading/writing to the underlying
+         *            {@link FileDescriptor}, but they can no longer deliver
+         *            reliable close/error events.
+         */
+        public void onClose(IOException e, boolean fromDetach);
+    }
+
+    /**
+     * Internal class representing a remote status read by
+     * {@link ParcelFileDescriptor#readCommStatus(FileDescriptor, byte[])}.
+     */
+    private static class Status {
+        /** Special value indicating remote side died. */
+        public static final int DEAD = -2;
+        /** Special value indicating no status should be written. */
+        public static final int SILENCE = -1;
+
+        /** Remote reported that everything went better than expected. */
+        public static final int OK = 0;
+        /** Remote reported error; length and message follow. */
+        public static final int ERROR = 1;
+        /** Remote reported {@link #detachFd()} and went rogue. */
+        public static final int DETACHED = 2;
+        /** Remote reported their object was finalized. */
+        public static final int LEAKED = 3;
+
+        public final int status;
+        public final String msg;
+
+        public Status(int status) {
+            this(status, null);
+        }
+
+        public Status(int status, String msg) {
+            this.status = status;
+            this.msg = msg;
+        }
+
+        public IOException asIOException() {
+            switch (status) {
+                case DEAD:
+                    return new IOException("Remote side is dead");
+                case OK:
+                    return null;
+                case ERROR:
+                    return new IOException("Remote error: " + msg);
+                case DETACHED:
+                    return new IOException("Remote side is detached");
+                case LEAKED:
+                    return new IOException("Remote side was leaked");
+                default:
+                    return new IOException("Unknown status: " + status);
+            }
+        }
+    }
+
+    /**
+     * Bridge to watch for remote status, and deliver to listener. Currently
+     * requires that communication socket is <em>blocking</em>.
+     */
+    private static final class ListenerBridge extends Thread {
+        // TODO: switch to using Looper to avoid burning a thread
+
+        private FileDescriptor mCommFd;
+        private final Handler mHandler;
+
+        public ListenerBridge(FileDescriptor comm, Looper looper, final OnCloseListener listener) {
+            mCommFd = comm;
+            mHandler = new Handler(looper) {
+                @Override
+                public void handleMessage(Message msg) {
+                    final Status s = (Status) msg.obj;
+                    if (s.status == Status.DETACHED) {
+                        listener.onClose(null, true);
+                    } else if (s.status == Status.OK) {
+                        listener.onClose(null, false);
+                    } else {
+                        listener.onClose(s.asIOException(), false);
+                    }
+                }
+            };
+        }
+
+        @Override
+        public void run() {
+            try {
+                final byte[] buf = new byte[MAX_STATUS];
+                final Status status = readCommStatus(mCommFd, buf);
+                mHandler.obtainMessage(0, status).sendToTarget();
+            } finally {
+                IoUtils.closeQuietly(mCommFd);
+                mCommFd = null;
+            }
+        }
+    }
 }
diff --git a/core/jni/Android.mk b/core/jni/Android.mk
index 0efa227..65b3678 100644
--- a/core/jni/Android.mk
+++ b/core/jni/Android.mk
@@ -63,7 +63,6 @@ LOCAL_SRC_FILES:= \
 	android_os_FileUtils.cpp \
 	android_os_MemoryFile.cpp \
 	android_os_MessageQueue.cpp \
-	android_os_ParcelFileDescriptor.cpp \
 	android_os_Parcel.cpp \
 	android_os_SELinux.cpp \
 	android_os_SystemClock.cpp \
diff --git a/core/jni/AndroidRuntime.cpp b/core/jni/AndroidRuntime.cpp
index 91fdcc2..63310ab 100644
--- a/core/jni/AndroidRuntime.cpp
+++ b/core/jni/AndroidRuntime.cpp
@@ -135,7 +135,6 @@ extern int register_android_text_format_Time(JNIEnv* env);
 extern int register_android_os_Debug(JNIEnv* env);
 extern int register_android_os_MessageQueue(JNIEnv* env);
 extern int register_android_os_Parcel(JNIEnv* env);
-extern int register_android_os_ParcelFileDescriptor(JNIEnv *env);
 extern int register_android_os_SELinux(JNIEnv* env);
 extern int register_android_os_SystemProperties(JNIEnv *env);
 extern int register_android_os_SystemClock(JNIEnv* env);
@@ -1178,7 +1177,6 @@ static const RegJNIRec gRegJNI[] = {
     REG_JNI(register_android_os_FileObserver),
     REG_JNI(register_android_os_FileUtils),
     REG_JNI(register_android_os_MessageQueue),
-    REG_JNI(register_android_os_ParcelFileDescriptor),
     REG_JNI(register_android_os_SELinux),
     REG_JNI(register_android_os_Trace),
     REG_JNI(register_android_os_UEventObserver),
diff --git a/core/jni/android_os_ParcelFileDescriptor.cpp b/core/jni/android_os_ParcelFileDescriptor.cpp
deleted file mode 100644
index 99a2d04..0000000
--- a/core/jni/android_os_ParcelFileDescriptor.cpp
+++ /dev/null
@@ -1,151 +0,0 @@
-/*
- * Copyright (C) 2008 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.
- */
-
-//#define LOG_NDEBUG 0
-
-#include "JNIHelp.h"
-
-#include <fcntl.h>
-#include <sys/stat.h>
-#include <stdio.h>
-
-#include <utils/Log.h>
-
-#include <android_runtime/AndroidRuntime.h>
-
-namespace android
-{
-
-static struct parcel_file_descriptor_offsets_t
-{
-    jfieldID mFileDescriptor;
-} gParcelFileDescriptorOffsets;
-
-static jobject android_os_ParcelFileDescriptor_getFileDescriptorFromFd(JNIEnv* env,
-    jobject clazz, jint origfd)
-{
-    int fd = dup(origfd);
-    if (fd < 0) {
-        jniThrowException(env, "java/io/IOException", strerror(errno));
-        return NULL;
-    }
-    return jniCreateFileDescriptor(env, fd);
-}
-
-static jobject android_os_ParcelFileDescriptor_getFileDescriptorFromFdNoDup(JNIEnv* env,
-    jobject clazz, jint fd)
-{
-    return jniCreateFileDescriptor(env, fd);
-}
-
-static void android_os_ParcelFileDescriptor_createPipeNative(JNIEnv* env,
-    jobject clazz, jobjectArray outFds)
-{
-    int fds[2];
-    if (pipe(fds) < 0) {
-        int therr = errno;
-        jniThrowException(env, "java/io/IOException", strerror(therr));
-        return;
-    }
-
-    for (int i=0; i<2; i++) {
-        jobject fdObj = jniCreateFileDescriptor(env, fds[i]);
-        env->SetObjectArrayElement(outFds, i, fdObj);
-    }
-}
-
-static jint getFd(JNIEnv* env, jobject clazz)
-{
-    jobject descriptor = env->GetObjectField(clazz, gParcelFileDescriptorOffsets.mFileDescriptor);
-    if (descriptor == NULL) return -1;
-    return jniGetFDFromFileDescriptor(env, descriptor);
-}
-
-static jlong android_os_ParcelFileDescriptor_getStatSize(JNIEnv* env,
-    jobject clazz)
-{
-    jint fd = getFd(env, clazz);
-    if (fd < 0) {
-        jniThrowException(env, "java/lang/IllegalArgumentException", "bad file descriptor");
-        return -1;
-    }
-
-    struct stat st;
-    if (fstat(fd, &st) != 0) {
-        return -1;
-    }
-
-    if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) {
-        return st.st_size;
-    }
-
-    return -1;
-}
-
-static jlong android_os_ParcelFileDescriptor_seekTo(JNIEnv* env,
-    jobject clazz, jlong pos)
-{
-    jint fd = getFd(env, clazz);
-    if (fd < 0) {
-        jniThrowException(env, "java/lang/IllegalArgumentException", "bad file descriptor");
-        return -1;
-    }
-
-    return lseek(fd, pos, SEEK_SET);
-}
-
-static jlong android_os_ParcelFileDescriptor_getFdNative(JNIEnv* env, jobject clazz)
-{
-    jint fd = getFd(env, clazz);
-    if (fd < 0) {
-        jniThrowException(env, "java/lang/IllegalArgumentException", "bad file descriptor");
-        return -1;
-    }
-
-    return fd;
-}
-
-static const JNINativeMethod gParcelFileDescriptorMethods[] = {
-    {"getFileDescriptorFromFd", "(I)Ljava/io/FileDescriptor;",
-        (void*)android_os_ParcelFileDescriptor_getFileDescriptorFromFd},
-    {"getFileDescriptorFromFdNoDup", "(I)Ljava/io/FileDescriptor;",
-        (void*)android_os_ParcelFileDescriptor_getFileDescriptorFromFdNoDup},
-    {"createPipeNative", "([Ljava/io/FileDescriptor;)V",
-        (void*)android_os_ParcelFileDescriptor_createPipeNative},
-    {"getStatSize", "()J",
-        (void*)android_os_ParcelFileDescriptor_getStatSize},
-    {"seekTo", "(J)J",
-        (void*)android_os_ParcelFileDescriptor_seekTo},
-    {"getFdNative", "()I",
-        (void*)android_os_ParcelFileDescriptor_getFdNative}
-};
-
-const char* const kParcelFileDescriptorPathName = "android/os/ParcelFileDescriptor";
-
-int register_android_os_ParcelFileDescriptor(JNIEnv* env)
-{
-    jclass clazz = env->FindClass(kParcelFileDescriptorPathName);
-    LOG_FATAL_IF(clazz == NULL, "Unable to find class android.os.ParcelFileDescriptor");
-    gParcelFileDescriptorOffsets.mFileDescriptor = env->GetFieldID(clazz, "mFileDescriptor", "Ljava/io/FileDescriptor;");
-    LOG_FATAL_IF(gParcelFileDescriptorOffsets.mFileDescriptor == NULL,
-                 "Unable to find mFileDescriptor field in android.os.ParcelFileDescriptor");
-
-    return AndroidRuntime::registerNativeMethods(
-        env, kParcelFileDescriptorPathName,
-        gParcelFileDescriptorMethods, NELEM(gParcelFileDescriptorMethods));
-}
-
-}