1 files changed, 168 insertions, 0 deletions
diff --git a/services/core/java/com/android/server/clipboard/EmulatorClipboardMonitor.java b/services/core/java/com/android/server/clipboard/EmulatorClipboardMonitor.java
new file mode 100644
index 000000000000..62b701aff398
--- /dev/null
+++ b/services/core/java/com/android/server/clipboard/EmulatorClipboardMonitor.java
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2021 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.server.clipboard;
+
+import android.annotation.Nullable;
+import android.content.ClipData;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.OsConstants;
+import android.system.VmSocketAddress;
+import android.util.Slog;
+
+import java.io.FileDescriptor;
+import java.io.InterruptedIOException;
+import java.net.SocketException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.util.Arrays;
+import java.util.function.Consumer;
+
+// The following class is Android Emulator specific. It is used to read and
+// write contents of the host system's clipboard.
+class EmulatorClipboardMonitor implements Consumer<ClipData> {
+    private static final String TAG = "EmulatorClipboardMonitor";
+    private static final String PIPE_NAME = "pipe:clipboard";
+    private static final int HOST_PORT = 5000;
+    private final Thread mHostMonitorThread;
+    private FileDescriptor mPipe = null;
+
+    private static byte[] createOpenHandshake() {
+        // String.getBytes doesn't include the null terminator,
+        // but the QEMU pipe device requires the pipe service name
+        // to be null-terminated.
+
+        final byte[] bits = Arrays.copyOf(PIPE_NAME.getBytes(), PIPE_NAME.length() + 1);
+        bits[PIPE_NAME.length()] = 0;
+        return bits;
+    }
+
+    private boolean isPipeOpened() {
+        return mPipe != null;
+    }
+
+    private synchronized boolean openPipe() {
+        if (mPipe != null) {
+            return true;
+        }
+
+        try {
+            final FileDescriptor fd = Os.socket(OsConstants.AF_VSOCK, OsConstants.SOCK_STREAM, 0);
+
+            try {
+                Os.connect(fd, new VmSocketAddress(HOST_PORT, OsConstants.VMADDR_CID_HOST));
+
+                final byte[] handshake = createOpenHandshake();
+                Os.write(fd, handshake, 0, handshake.length);
+                mPipe = fd;
+                return true;
+            } catch (ErrnoException | SocketException | InterruptedIOException e) {
+                Os.close(fd);
+            }
+        } catch (ErrnoException e) {
+        }
+
+        return false;
+    }
+
+    private synchronized void closePipe() {
+        try {
+            final FileDescriptor fd = mPipe;
+            mPipe = null;
+            if (fd != null) {
+                Os.close(fd);
+            }
+        } catch (ErrnoException ignore) {
+        }
+    }
+
+    private byte[] receiveMessage() throws ErrnoException, InterruptedIOException {
+        final byte[] lengthBits = new byte[4];
+        Os.read(mPipe, lengthBits, 0, lengthBits.length);
+
+        final ByteBuffer bb = ByteBuffer.wrap(lengthBits);
+        bb.order(ByteOrder.LITTLE_ENDIAN);
+        final int msgLen = bb.getInt();
+
+        final byte[] msg = new byte[msgLen];
+        Os.read(mPipe, msg, 0, msg.length);
+
+        return msg;
+    }
+
+    private void sendMessage(final byte[] msg) throws ErrnoException, InterruptedIOException {
+        final byte[] lengthBits = new byte[4];
+        final ByteBuffer bb = ByteBuffer.wrap(lengthBits);
+        bb.order(ByteOrder.LITTLE_ENDIAN);
+        bb.putInt(msg.length);
+
+        Os.write(mPipe, lengthBits, 0, lengthBits.length);
+        Os.write(mPipe, msg, 0, msg.length);
+    }
+
+    EmulatorClipboardMonitor(final Consumer<ClipData> setAndroidClipboard) {
+        this.mHostMonitorThread = new Thread(() -> {
+            while (!Thread.interrupted()) {
+                try {
+                    // There's no guarantee that QEMU pipes will be ready at the moment
+                    // this method is invoked. We simply try to get the pipe open and
+                    // retry on failure indefinitely.
+                    while (!openPipe()) {
+                        Thread.sleep(100);
+                    }
+
+                    final byte[] receivedData = receiveMessage();
+
+                    final String str = new String(receivedData);
+                    final ClipData clip = new ClipData("host clipboard",
+                                                       new String[]{"text/plain"},
+                                                       new ClipData.Item(str));
+
+                    setAndroidClipboard.accept(clip);
+                } catch (ErrnoException | InterruptedIOException e) {
+                    closePipe();
+                } catch (InterruptedException | IllegalArgumentException e) {
+                }
+            }
+        });
+
+        this.mHostMonitorThread.start();
+    }
+
+    @Override
+    public void accept(final @Nullable ClipData clip) {
+        if (clip == null) {
+            setHostClipboardImpl("");
+        } else if (clip.getItemCount() > 0) {
+            final CharSequence text = clip.getItemAt(0).getText();
+            if (text != null) {
+                setHostClipboardImpl(text.toString());
+            }
+        }
+    }
+
+    private void setHostClipboardImpl(final String value) {
+        try {
+            if (isPipeOpened()) {
+                sendMessage(value.getBytes());
+            }
+        } catch (ErrnoException | InterruptedIOException e) {
+            Slog.e(TAG, "Failed to set host clipboard " + e.getMessage());
+        } catch (IllegalArgumentException e) {
+        }
+    }
+}