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Commit d99f9cab authored by Jeff Sharkey's avatar Jeff Sharkey
Browse files

Skip writing PFD status when comm is closed. 

If the remote side of PFD has already written a status message, then
they've also closed their end of the comm FD, and we're going to
EPIPE if we try sending our own status.  So, skip writing status if
a remote status is present.

Only one end of the openFile() comm socket needs to be blocking,
otherwise detachFd() would end up blocking forever.

Bug: 11385467
Change-Id: I346d40cc1ca4a6683cec4c2d2b7db2b32ac94a55
parent 758f97e4

core/java/android/os/ParcelFileDescriptor.java

+27 −25
Original line number Diff line number Diff line
@@ -231,10 +231,11 @@ public class ParcelFileDescriptor implements Parcelable, Closeable { 
        final FileDescriptor fd = openInternal(file, mode);

        if (fd == null) return null;



        final FileDescriptor[] comm = createCommSocketPair(true);

        final FileDescriptor[] comm = createCommSocketPair();

        final ParcelFileDescriptor pfd = new ParcelFileDescriptor(fd, comm[0]);



        // Kick off thread to watch for status updates

        IoUtils.setBlocking(comm[1], true);

        final ListenerBridge bridge = new ListenerBridge(comm[1], handler.getLooper(), listener);

        bridge.start();
@@ -378,7 +379,7 @@ public class ParcelFileDescriptor implements Parcelable, Closeable { 
     */

    public static ParcelFileDescriptor[] createReliablePipe() throws IOException {

        try {

            final FileDescriptor[] comm = createCommSocketPair(false);

            final FileDescriptor[] comm = createCommSocketPair();

            final FileDescriptor[] fds = Libcore.os.pipe();

            return new ParcelFileDescriptor[] {

                    new ParcelFileDescriptor(fds[0], comm[0]),
@@ -416,7 +417,7 @@ public class ParcelFileDescriptor implements Parcelable, Closeable { 
     */

    public static ParcelFileDescriptor[] createReliableSocketPair() throws IOException {

        try {

            final FileDescriptor[] comm = createCommSocketPair(false);

            final FileDescriptor[] comm = createCommSocketPair();

            final FileDescriptor fd0 = new FileDescriptor();

            final FileDescriptor fd1 = new FileDescriptor();

            Libcore.os.socketpair(AF_UNIX, SOCK_STREAM, 0, fd0, fd1);
@@ -428,13 +429,13 @@ public class ParcelFileDescriptor implements Parcelable, Closeable { 
        }

    }



    private static FileDescriptor[] createCommSocketPair(boolean blocking) throws IOException {

    private static FileDescriptor[] createCommSocketPair() 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);

            IoUtils.setBlocking(comm1, false);

            IoUtils.setBlocking(comm2, false);

            return new FileDescriptor[] { comm1, comm2 };

        } catch (ErrnoException e) {

            throw e.rethrowAsIOException();
@@ -670,8 +671,16 @@ public class ParcelFileDescriptor implements Parcelable, Closeable { 
        }



        try {

            if (status == Status.SILENCE) return;



            // Since we're about to close, read off any remote status. It's

            // okay to remember missing here.

            mStatus = readCommStatus(mCommFd, getOrCreateStatusBuffer());



            // Skip writing status when other end has already gone away.

            if (mStatus != null) return;



            try {

                if (status != Status.SILENCE) {

                final byte[] buf = getOrCreateStatusBuffer();

                int writePtr = 0;
@@ -686,18 +695,11 @@ public class ParcelFileDescriptor implements Parcelable, Closeable { 
                }



                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;