FileBridge.java revision 78cc340c2de873d6995c283b777476f7237d690f
178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey/* 278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * Copyright (C) 2014 The Android Open Source Project 378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * 478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * Licensed under the Apache License, Version 2.0 (the "License"); 578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * you may not use this file except in compliance with the License. 678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * You may obtain a copy of the License at 778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * 878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * http://www.apache.org/licenses/LICENSE-2.0 978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * 1078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * Unless required by applicable law or agreed to in writing, software 1178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * distributed under the License is distributed on an "AS IS" BASIS, 1278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 1378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * See the License for the specific language governing permissions and 1478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * limitations under the License. 1578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey */ 1678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 1778cc340c2de873d6995c283b777476f7237d690fJeff Sharkeypackage android.os; 1878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 1978cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport static android.system.OsConstants.AF_UNIX; 2078cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport static android.system.OsConstants.SOCK_STREAM; 2178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 2278cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport android.system.ErrnoException; 2378cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport android.system.Os; 2478cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport android.util.Log; 2578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 2678cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport libcore.io.IoBridge; 2778cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport libcore.io.IoUtils; 2878cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport libcore.io.Memory; 2978cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport libcore.io.Streams; 3078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 3178cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport java.io.FileDescriptor; 3278cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport java.io.IOException; 3378cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport java.io.OutputStream; 3478cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport java.io.SyncFailedException; 3578cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport java.nio.ByteOrder; 3678cc340c2de873d6995c283b777476f7237d690fJeff Sharkeyimport java.util.Arrays; 3778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 3878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey/** 3978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * Simple bridge that allows file access across process boundaries without 4078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * returning the underlying {@link FileDescriptor}. This is useful when the 4178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * server side needs to strongly assert that a client side is completely 4278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * hands-off. 4378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * 4478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey * @hide 4578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey */ 4678cc340c2de873d6995c283b777476f7237d690fJeff Sharkeypublic class FileBridge extends Thread { 4778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey private static final String TAG = "FileBridge"; 4878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 4978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey // TODO: consider extending to support bidirectional IO 5078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 5178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey private static final int MSG_LENGTH = 8; 5278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 5378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey /** CMD_WRITE [len] [data] */ 5478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey private static final int CMD_WRITE = 1; 5578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey /** CMD_FSYNC */ 5678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey private static final int CMD_FSYNC = 2; 5778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 5878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey private FileDescriptor mTarget; 5978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 6078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey private final FileDescriptor mServer = new FileDescriptor(); 6178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey private final FileDescriptor mClient = new FileDescriptor(); 6278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 6378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey private volatile boolean mClosed; 6478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 6578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public FileBridge() { 6678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey try { 6778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey Os.socketpair(AF_UNIX, SOCK_STREAM, 0, mServer, mClient); 6878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } catch (ErrnoException e) { 6978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey throw new RuntimeException("Failed to create bridge"); 7078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 7178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 7278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 7378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public boolean isClosed() { 7478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey return mClosed; 7578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 7678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 7778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public void setTargetFile(FileDescriptor target) { 7878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey mTarget = target; 7978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 8078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 8178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public FileDescriptor getClientSocket() { 8278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey return mClient; 8378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 8478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 8578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey @Override 8678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public void run() { 8778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey final byte[] temp = new byte[8192]; 8878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey try { 8978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey while (IoBridge.read(mServer, temp, 0, MSG_LENGTH) == MSG_LENGTH) { 9078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey final int cmd = Memory.peekInt(temp, 0, ByteOrder.BIG_ENDIAN); 9178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 9278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey if (cmd == CMD_WRITE) { 9378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey // Shuttle data into local file 9478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey int len = Memory.peekInt(temp, 4, ByteOrder.BIG_ENDIAN); 9578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey while (len > 0) { 9678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey int n = IoBridge.read(mServer, temp, 0, Math.min(temp.length, len)); 9778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey IoBridge.write(mTarget, temp, 0, n); 9878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey len -= n; 9978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 10078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 10178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } else if (cmd == CMD_FSYNC) { 10278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey // Sync and echo back to confirm 10378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey Os.fsync(mTarget); 10478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey IoBridge.write(mServer, temp, 0, MSG_LENGTH); 10578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 10678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 10778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 10878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey // Client was closed; one last fsync 10978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey Os.fsync(mTarget); 11078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 11178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } catch (ErrnoException e) { 11278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey Log.e(TAG, "Failed during bridge: ", e); 11378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } catch (IOException e) { 11478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey Log.e(TAG, "Failed during bridge: ", e); 11578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } finally { 11678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey IoUtils.closeQuietly(mTarget); 11778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey IoUtils.closeQuietly(mServer); 11878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey IoUtils.closeQuietly(mClient); 11978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey mClosed = true; 12078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 12178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 12278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 12378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public static class FileBridgeOutputStream extends OutputStream { 12478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey private final FileDescriptor mClient; 12578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey private final byte[] mTemp = new byte[MSG_LENGTH]; 12678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 12778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public FileBridgeOutputStream(FileDescriptor client) { 12878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey mClient = client; 12978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 13078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 13178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey @Override 13278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public void close() throws IOException { 13378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey IoBridge.closeAndSignalBlockedThreads(mClient); 13478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 13578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 13678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey @Override 13778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public void flush() throws IOException { 13878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey Memory.pokeInt(mTemp, 0, CMD_FSYNC, ByteOrder.BIG_ENDIAN); 13978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey IoBridge.write(mClient, mTemp, 0, MSG_LENGTH); 14078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 14178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey // Wait for server to ack 14278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey if (IoBridge.read(mClient, mTemp, 0, MSG_LENGTH) == MSG_LENGTH) { 14378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey if (Memory.peekInt(mTemp, 0, ByteOrder.BIG_ENDIAN) == CMD_FSYNC) { 14478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey return; 14578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 14678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 14778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 14878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey throw new SyncFailedException("Failed to fsync() across bridge"); 14978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 15078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 15178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey @Override 15278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public void write(byte[] buffer, int byteOffset, int byteCount) throws IOException { 15378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey Arrays.checkOffsetAndCount(buffer.length, byteOffset, byteCount); 15478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey Memory.pokeInt(mTemp, 0, CMD_WRITE, ByteOrder.BIG_ENDIAN); 15578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey Memory.pokeInt(mTemp, 4, byteCount, ByteOrder.BIG_ENDIAN); 15678cc340c2de873d6995c283b777476f7237d690fJeff Sharkey IoBridge.write(mClient, mTemp, 0, MSG_LENGTH); 15778cc340c2de873d6995c283b777476f7237d690fJeff Sharkey IoBridge.write(mClient, buffer, byteOffset, byteCount); 15878cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 15978cc340c2de873d6995c283b777476f7237d690fJeff Sharkey 16078cc340c2de873d6995c283b777476f7237d690fJeff Sharkey @Override 16178cc340c2de873d6995c283b777476f7237d690fJeff Sharkey public void write(int oneByte) throws IOException { 16278cc340c2de873d6995c283b777476f7237d690fJeff Sharkey Streams.writeSingleByte(this, oneByte); 16378cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 16478cc340c2de873d6995c283b777476f7237d690fJeff Sharkey } 16578cc340c2de873d6995c283b777476f7237d690fJeff Sharkey} 166