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/*
* Copyright (C) 2014 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 android.os;
import static android.system.OsConstants.AF_UNIX;
import static android.system.OsConstants.SOCK_STREAM;
import android.system.ErrnoException;
import android.system.Os;
import android.util.Log;
import libcore.io.IoBridge;
import libcore.io.IoUtils;
import libcore.io.Memory;
import libcore.io.Streams;
import java.io.FileDescriptor;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteOrder;
import java.util.Arrays;
/**
* Simple bridge that allows file access across process boundaries without
* returning the underlying {@link FileDescriptor}. This is useful when the
* server side needs to strongly assert that a client side is completely
* hands-off.
*
* @hide
* @deprecated replaced by {@link RevocableFileDescriptor}
*/
@Deprecated
public class FileBridge extends Thread {
private static final String TAG = "FileBridge";
// TODO: consider extending to support bidirectional IO
private static final int MSG_LENGTH = 8;
/** CMD_WRITE [len] [data] */
private static final int CMD_WRITE = 1;
/** CMD_FSYNC */
private static final int CMD_FSYNC = 2;
/** CMD_CLOSE */
private static final int CMD_CLOSE = 3;
private FileDescriptor mTarget;
private final FileDescriptor mServer = new FileDescriptor();
private final FileDescriptor mClient = new FileDescriptor();
private volatile boolean mClosed;
public FileBridge() {
try {
Os.socketpair(AF_UNIX, SOCK_STREAM, 0, mServer, mClient);
} catch (ErrnoException e) {
throw new RuntimeException("Failed to create bridge");
}
}
public boolean isClosed() {
return mClosed;
}
public void forceClose() {
IoUtils.closeQuietly(mTarget);
IoUtils.closeQuietly(mServer);
IoUtils.closeQuietly(mClient);
mClosed = true;
}
public void setTargetFile(FileDescriptor target) {
mTarget = target;
}
public FileDescriptor getClientSocket() {
return mClient;
}
@Override
public void run() {
final byte[] temp = new byte[8192];
try {
while (IoBridge.read(mServer, temp, 0, MSG_LENGTH) == MSG_LENGTH) {
final int cmd = Memory.peekInt(temp, 0, ByteOrder.BIG_ENDIAN);
if (cmd == CMD_WRITE) {
// Shuttle data into local file
int len = Memory.peekInt(temp, 4, ByteOrder.BIG_ENDIAN);
while (len > 0) {
int n = IoBridge.read(mServer, temp, 0, Math.min(temp.length, len));
if (n == -1) {
throw new IOException(
"Unexpected EOF; still expected " + len + " bytes");
}
IoBridge.write(mTarget, temp, 0, n);
len -= n;
}
} else if (cmd == CMD_FSYNC) {
// Sync and echo back to confirm
Os.fsync(mTarget);
IoBridge.write(mServer, temp, 0, MSG_LENGTH);
} else if (cmd == CMD_CLOSE) {
// Close and echo back to confirm
Os.fsync(mTarget);
Os.close(mTarget);
mClosed = true;
IoBridge.write(mServer, temp, 0, MSG_LENGTH);
break;
}
}
} catch (ErrnoException | IOException e) {
Log.wtf(TAG, "Failed during bridge", e);
} finally {
forceClose();
}
}
public static class FileBridgeOutputStream extends OutputStream {
private final ParcelFileDescriptor mClientPfd;
private final FileDescriptor mClient;
private final byte[] mTemp = new byte[MSG_LENGTH];
public FileBridgeOutputStream(ParcelFileDescriptor clientPfd) {
mClientPfd = clientPfd;
mClient = clientPfd.getFileDescriptor();
}
public FileBridgeOutputStream(FileDescriptor client) {
mClientPfd = null;
mClient = client;
}
@Override
public void close() throws IOException {
try {
writeCommandAndBlock(CMD_CLOSE, "close()");
} finally {
IoBridge.closeAndSignalBlockedThreads(mClient);
IoUtils.closeQuietly(mClientPfd);
}
}
public void fsync() throws IOException {
writeCommandAndBlock(CMD_FSYNC, "fsync()");
}
private void writeCommandAndBlock(int cmd, String cmdString) throws IOException {
Memory.pokeInt(mTemp, 0, cmd, ByteOrder.BIG_ENDIAN);
IoBridge.write(mClient, mTemp, 0, MSG_LENGTH);
// Wait for server to ack
if (IoBridge.read(mClient, mTemp, 0, MSG_LENGTH) == MSG_LENGTH) {
if (Memory.peekInt(mTemp, 0, ByteOrder.BIG_ENDIAN) == cmd) {
return;
}
}
throw new IOException("Failed to execute " + cmdString + " across bridge");
}
@Override
public void write(byte[] buffer, int byteOffset, int byteCount) throws IOException {
Arrays.checkOffsetAndCount(buffer.length, byteOffset, byteCount);
Memory.pokeInt(mTemp, 0, CMD_WRITE, ByteOrder.BIG_ENDIAN);
Memory.pokeInt(mTemp, 4, byteCount, ByteOrder.BIG_ENDIAN);
IoBridge.write(mClient, mTemp, 0, MSG_LENGTH);
IoBridge.write(mClient, buffer, byteOffset, byteCount);
}
@Override
public void write(int oneByte) throws IOException {
Streams.writeSingleByte(this, oneByte);
}
}
}
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