/*
* Copyright (C) 2007 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;
import android.net.LocalSocket;
import android.net.LocalSocketAddress;
import android.os.Build;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.os.PowerManager;
import android.os.SystemClock;
import android.util.LocalLog;
import android.util.Slog;
import com.android.internal.annotations.VisibleForTesting;
import com.google.android.collect.Lists;
import java.io.FileDescriptor;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.LinkedList;
/**
* Generic connector class for interfacing with a native daemon which uses the
* {@code libsysutils} FrameworkListener protocol.
*/
final class NativeDaemonConnector implements Runnable, Handler.Callback, Watchdog.Monitor {
private static final boolean LOGD = false;
private final static boolean VDBG = false;
private final String TAG;
private String mSocket;
private OutputStream mOutputStream;
private LocalLog mLocalLog;
private final ResponseQueue mResponseQueue;
private final PowerManager.WakeLock mWakeLock;
private final Looper mLooper;
private INativeDaemonConnectorCallbacks mCallbacks;
private Handler mCallbackHandler;
private AtomicInteger mSequenceNumber;
private static final int DEFAULT_TIMEOUT = 1 * 60 * 1000; /* 1 minute */
private static final long WARN_EXECUTE_DELAY_MS = 500; /* .5 sec */
/** Lock held whenever communicating with native daemon. */
private final Object mDaemonLock = new Object();
private final int BUFFER_SIZE = 4096;
NativeDaemonConnector(INativeDaemonConnectorCallbacks callbacks, String socket,
int responseQueueSize, String logTag, int maxLogSize, PowerManager.WakeLock wl) {
this(callbacks, socket, responseQueueSize, logTag, maxLogSize, wl,
FgThread.get().getLooper());
}
NativeDaemonConnector(INativeDaemonConnectorCallbacks callbacks, String socket,
int responseQueueSize, String logTag, int maxLogSize, PowerManager.WakeLock wl,
Looper looper) {
mCallbacks = callbacks;
mSocket = socket;
mResponseQueue = new ResponseQueue(responseQueueSize);
mWakeLock = wl;
if (mWakeLock != null) {
mWakeLock.setReferenceCounted(true);
}
mLooper = looper;
mSequenceNumber = new AtomicInteger(0);
TAG = logTag != null ? logTag : "NativeDaemonConnector";
mLocalLog = new LocalLog(maxLogSize);
}
@Override
public void run() {
mCallbackHandler = new Handler(mLooper, this);
while (true) {
try {
listenToSocket();
} catch (Exception e) {
loge("Error in NativeDaemonConnector: " + e);
SystemClock.sleep(5000);
}
}
}
@Override
public boolean handleMessage(Message msg) {
String event = (String) msg.obj;
try {
if (!mCallbacks.onEvent(msg.what, event, NativeDaemonEvent.unescapeArgs(event))) {
log(String.format("Unhandled event '%s'", event));
}
} catch (Exception e) {
loge("Error handling '" + event + "': " + e);
} finally {
if (mCallbacks.onCheckHoldWakeLock(msg.what) && mWakeLock != null) {
mWakeLock.release();
}
}
return true;
}
private LocalSocketAddress determineSocketAddress() {
// If we're testing, set up a socket in a namespace that's accessible to test code.
// In order to ensure that unprivileged apps aren't able to impersonate native daemons on
// production devices, even if said native daemons ill-advisedly pick a socket name that
// starts with __test__, only allow this on debug builds.
if (mSocket.startsWith("__test__") && Build.IS_DEBUGGABLE) {
return new LocalSocketAddress(mSocket);
} else {
return new LocalSocketAddress(mSocket, LocalSocketAddress.Namespace.RESERVED);
}
}
private void listenToSocket() throws IOException {
LocalSocket socket = null;
try {
socket = new LocalSocket();
LocalSocketAddress address = determineSocketAddress();
socket.connect(address);
InputStream inputStream = socket.getInputStream();
synchronized (mDaemonLock) {
mOutputStream = socket.getOutputStream();
}
mCallbacks.onDaemonConnected();
byte[] buffer = new byte[BUFFER_SIZE];
int start = 0;
while (true) {
int count = inputStream.read(buffer, start, BUFFER_SIZE - start);
if (count < 0) {
loge("got " + count + " reading with start = " + start);
break;
}
// Add our starting point to the count and reset the start.
count += start;
start = 0;
for (int i = 0; i < count; i++) {
if (buffer[i] == 0) {
// Note - do not log this raw message since it may contain
// sensitive data
final String rawEvent = new String(
buffer, start, i - start, StandardCharsets.UTF_8);
boolean releaseWl = false;
try {
final NativeDaemonEvent event = NativeDaemonEvent.parseRawEvent(
rawEvent);
log("RCV <- {" + event + "}");
if (event.isClassUnsolicited()) {
// TODO: migrate to sending NativeDaemonEvent instances
if (mCallbacks.onCheckHoldWakeLock(event.getCode())
&& mWakeLock != null) {
mWakeLock.acquire();
releaseWl = true;
}
if (mCallbackHandler.sendMessage(mCallbackHandler.obtainMessage(
event.getCode(), event.getRawEvent()))) {
releaseWl = false;
}
} else {
mResponseQueue.add(event.getCmdNumber(), event);
}
} catch (IllegalArgumentException e) {
log("Problem parsing message " + e);
} finally {
if (releaseWl) {
mWakeLock.acquire();
}
}
start = i + 1;
}
}
if (start == 0) {
log("RCV incomplete");
}
// We should end at the amount we read. If not, compact then
// buffer and read again.
if (start != count) {
final int remaining = BUFFER_SIZE - start;
System.arraycopy(buffer, start, buffer, 0, remaining);
start = remaining;
} else {
start = 0;
}
}
} catch (IOException ex) {
loge("Communications error: " + ex);
throw ex;
} finally {
synchronized (mDaemonLock) {
if (mOutputStream != null) {
try {
loge("closing stream for " + mSocket);
mOutputStream.close();
} catch (IOException e) {
loge("Failed closing output stream: " + e);
}
mOutputStream = null;
}
}
try {
if (socket != null) {
socket.close();
}
} catch (IOException ex) {
loge("Failed closing socket: " + ex);
}
}
}
/**
* Wrapper around argument that indicates it's sensitive and shouldn't be
* logged.
*/
public static class SensitiveArg {
private final Object mArg;
public SensitiveArg(Object arg) {
mArg = arg;
}
@Override
public String toString() {
return String.valueOf(mArg);
}
}
/**
* Make command for daemon, escaping arguments as needed.
*/
@VisibleForTesting
static void makeCommand(StringBuilder rawBuilder, StringBuilder logBuilder, int sequenceNumber,
String cmd, Object... args) {
if (cmd.indexOf('\0') >= 0) {
throw new IllegalArgumentException("Unexpected command: " + cmd);
}
if (cmd.indexOf(' ') >= 0) {
throw new IllegalArgumentException("Arguments must be separate from command");
}
rawBuilder.append(sequenceNumber).append(' ').append(cmd);
logBuilder.append(sequenceNumber).append(' ').append(cmd);
for (Object arg : args) {
final String argString = String.valueOf(arg);
if (argString.indexOf('\0') >= 0) {
throw new IllegalArgumentException("Unexpected argument: " + arg);
}
rawBuilder.append(' ');
logBuilder.append(' ');
appendEscaped(rawBuilder, argString);
if (arg instanceof SensitiveArg) {
logBuilder.append("[scrubbed]");
} else {
appendEscaped(logBuilder, argString);
}
}
rawBuilder.append('\0');
}
/**
* Issue the given command to the native daemon and return a single expected
* response.
*
* @throws NativeDaemonConnectorException when problem communicating with
* native daemon, or if the response matches
* {@link NativeDaemonEvent#isClassClientError()} or
* {@link NativeDaemonEvent#isClassServerError()}.
*/
public NativeDaemonEvent execute(Command cmd) throws NativeDaemonConnectorException {
return execute(cmd.mCmd, cmd.mArguments.toArray());
}
/**
* Issue the given command to the native daemon and return a single expected
* response. Any arguments must be separated from base command so they can
* be properly escaped.
*
* @throws NativeDaemonConnectorException when problem communicating with
* native daemon, or if the response matches
* {@link NativeDaemonEvent#isClassClientError()} or
* {@link NativeDaemonEvent#isClassServerError()}.
*/
public NativeDaemonEvent execute(String cmd, Object... args)
throws NativeDaemonConnectorException {
final NativeDaemonEvent[] events = executeForList(cmd, args);
if (events.length != 1) {
throw new NativeDaemonConnectorException(
"Expected exactly one response, but received " + events.length);
}
return events[0];
}
/**
* Issue the given command to the native daemon and return any
* {@link NativeDaemonEvent#isClassContinue()} responses, including the
* final terminal response.
*
* @throws NativeDaemonConnectorException when problem communicating with
* native daemon, or if the response matches
* {@link NativeDaemonEvent#isClassClientError()} or
* {@link NativeDaemonEvent#isClassServerError()}.
*/
public NativeDaemonEvent[] executeForList(Command cmd) throws NativeDaemonConnectorException {
return executeForList(cmd.mCmd, cmd.mArguments.toArray());
}
/**
* Issue the given command to the native daemon and return any
* {@link NativeDaemonEvent#isClassContinue()} responses, including the
* final terminal response. Any arguments must be separated from base
* command so they can be properly escaped.
*
* @throws NativeDaemonConnectorException when problem communicating with
* native daemon, or if the response matches
* {@link NativeDaemonEvent#isClassClientError()} or
* {@link NativeDaemonEvent#isClassServerError()}.
*/
public NativeDaemonEvent[] executeForList(String cmd, Object... args)
throws NativeDaemonConnectorException {
return execute(DEFAULT_TIMEOUT, cmd, args);
}
/**
* Issue the given command to the native daemon and return any {@linke
* NativeDaemonEvent@isClassContinue()} responses, including the final
* terminal response. Note that the timeout does not count time in deep
* sleep. Any arguments must be separated from base command so they can be
* properly escaped.
*
* @throws NativeDaemonConnectorException when problem communicating with
* native daemon, or if the response matches
* {@link NativeDaemonEvent#isClassClientError()} or
* {@link NativeDaemonEvent#isClassServerError()}.
*/
public NativeDaemonEvent[] execute(int timeout, String cmd, Object... args)
throws NativeDaemonConnectorException {
final long startTime = SystemClock.elapsedRealtime();
final ArrayList<NativeDaemonEvent> events = Lists.newArrayList();
final StringBuilder rawBuilder = new StringBuilder();
final StringBuilder logBuilder = new StringBuilder();
final int sequenceNumber = mSequenceNumber.incrementAndGet();
makeCommand(rawBuilder, logBuilder, sequenceNumber, cmd, args);
final String rawCmd = rawBuilder.toString();
final String logCmd = logBuilder.toString();
log("SND -> {" + logCmd + "}");
synchronized (mDaemonLock) {
if (mOutputStream == null) {
throw new NativeDaemonConnectorException("missing output stream");
} else {
try {
mOutputStream.write(rawCmd.getBytes(StandardCharsets.UTF_8));
} catch (IOException e) {
throw new NativeDaemonConnectorException("problem sending command", e);
}
}
}
NativeDaemonEvent event = null;
do {
event = mResponseQueue.remove(sequenceNumber, timeout, logCmd);
if (event == null) {
loge("timed-out waiting for response to " + logCmd);
throw new NativeDaemonFailureException(logCmd, event);
}
if (VDBG) log("RMV <- {" + event + "}");
events.add(event);
} while (event.isClassContinue());
final long endTime = SystemClock.elapsedRealtime();
if (endTime - startTime > WARN_EXECUTE_DELAY_MS) {
loge("NDC Command {" + logCmd + "} took too long (" + (endTime - startTime) + "ms)");
}
if (event.isClassClientError()) {
throw new NativeDaemonArgumentException(logCmd, event);
}
if (event.isClassServerError()) {
throw new NativeDaemonFailureException(logCmd, event);
}
return events.toArray(new NativeDaemonEvent[events.size()]);
}
/**
* Append the given argument to {@link StringBuilder}, escaping as needed,
* and surrounding with quotes when it contains spaces.
*/
@VisibleForTesting
static void appendEscaped(StringBuilder builder, String arg) {
final boolean hasSpaces = arg.indexOf(' ') >= 0;
if (hasSpaces) {
builder.append('"');
}
final int length = arg.length();
for (int i = 0; i < length; i++) {
final char c = arg.charAt(i);
if (c == '"') {
builder.append("\\\"");
} else if (c == '\\') {
builder.append("\\\\");
} else {
builder.append(c);
}
}
if (hasSpaces) {
builder.append('"');
}
}
private static class NativeDaemonArgumentException extends NativeDaemonConnectorException {
public NativeDaemonArgumentException(String command, NativeDaemonEvent event) {
super(command, event);
}
@Override
public IllegalArgumentException rethrowAsParcelableException() {
throw new IllegalArgumentException(getMessage(), this);
}
}
private static class NativeDaemonFailureException extends NativeDaemonConnectorException {
public NativeDaemonFailureException(String command, NativeDaemonEvent event) {
super(command, event);
}
}
/**
* Command builder that handles argument list building. Any arguments must
* be separated from base command so they can be properly escaped.
*/
public static class Command {
private String mCmd;
private ArrayList<Object> mArguments = Lists.newArrayList();
public Command(String cmd, Object... args) {
mCmd = cmd;
for (Object arg : args) {
appendArg(arg);
}
}
public Command appendArg(Object arg) {
mArguments.add(arg);
return this;
}
}
/** {@inheritDoc} */
public void monitor() {
synchronized (mDaemonLock) { }
}
public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
mLocalLog.dump(fd, pw, args);
pw.println();
mResponseQueue.dump(fd, pw, args);
}
private void log(String logstring) {
if (LOGD) Slog.d(TAG, logstring);
mLocalLog.log(logstring);
}
private void loge(String logstring) {
Slog.e(TAG, logstring);
mLocalLog.log(logstring);
}
private static class ResponseQueue {
private static class PendingCmd {
public final int cmdNum;
public final String logCmd;
public BlockingQueue<NativeDaemonEvent> responses =
new ArrayBlockingQueue<NativeDaemonEvent>(10);
// The availableResponseCount member is used to track when we can remove this
// instance from the ResponseQueue.
// This is used under the protection of a sync of the mPendingCmds object.
// A positive value means we've had more writers retreive this object while
// a negative value means we've had more readers. When we've had an equal number
// (it goes to zero) we can remove this object from the mPendingCmds list.
// Note that we may have more responses for this command (and more readers
// coming), but that would result in a new PendingCmd instance being created
// and added with the same cmdNum.
// Also note that when this goes to zero it just means a parity of readers and
// writers have retrieved this object - not that they are done using it. The
// responses queue may well have more responses yet to be read or may get more
// responses added to it. But all those readers/writers have retreived and
// hold references to this instance already so it can be removed from
// mPendingCmds queue.
public int availableResponseCount;
public PendingCmd(int cmdNum, String logCmd) {
this.cmdNum = cmdNum;
this.logCmd = logCmd;
}
}
private final LinkedList<PendingCmd> mPendingCmds;
private int mMaxCount;
ResponseQueue(int maxCount) {
mPendingCmds = new LinkedList<PendingCmd>();
mMaxCount = maxCount;
}
public void add(int cmdNum, NativeDaemonEvent response) {
PendingCmd found = null;
synchronized (mPendingCmds) {
for (PendingCmd pendingCmd : mPendingCmds) {
if (pendingCmd.cmdNum == cmdNum) {
found = pendingCmd;
break;
}
}
if (found == null) {
// didn't find it - make sure our queue isn't too big before adding
while (mPendingCmds.size() >= mMaxCount) {
Slog.e("NativeDaemonConnector.ResponseQueue",
"more buffered than allowed: " + mPendingCmds.size() +
" >= " + mMaxCount);
// let any waiter timeout waiting for this
PendingCmd pendingCmd = mPendingCmds.remove();
Slog.e("NativeDaemonConnector.ResponseQueue",
"Removing request: " + pendingCmd.logCmd + " (" +
pendingCmd.cmdNum + ")");
}
found = new PendingCmd(cmdNum, null);
mPendingCmds.add(found);
}
found.availableResponseCount++;
// if a matching remove call has already retrieved this we can remove this
// instance from our list
if (found.availableResponseCount == 0) mPendingCmds.remove(found);
}
try {
found.responses.put(response);
} catch (InterruptedException e) { }
}
// note that the timeout does not count time in deep sleep. If you don't want
// the device to sleep, hold a wakelock
public NativeDaemonEvent remove(int cmdNum, int timeoutMs, String logCmd) {
PendingCmd found = null;
synchronized (mPendingCmds) {
for (PendingCmd pendingCmd : mPendingCmds) {
if (pendingCmd.cmdNum == cmdNum) {
found = pendingCmd;
break;
}
}
if (found == null) {
found = new PendingCmd(cmdNum, logCmd);
mPendingCmds.add(found);
}
found.availableResponseCount--;
// if a matching add call has already retrieved this we can remove this
// instance from our list
if (found.availableResponseCount == 0) mPendingCmds.remove(found);
}
NativeDaemonEvent result = null;
try {
result = found.responses.poll(timeoutMs, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {}
if (result == null) {
Slog.e("NativeDaemonConnector.ResponseQueue", "Timeout waiting for response");
}
return result;
}
public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
pw.println("Pending requests:");
synchronized (mPendingCmds) {
for (PendingCmd pendingCmd : mPendingCmds) {
pw.println(" Cmd " + pendingCmd.cmdNum + " - " + pendingCmd.logCmd);
}
}
}
}
}
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