/*
* Copyright (C) 2012 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.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.ServiceConnection;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.ResolveInfo;
import android.content.pm.Signature;
import android.content.res.Resources;
import android.os.Handler;
import android.os.IBinder;
import android.os.UserHandle;
import android.util.Log;
import com.android.internal.content.PackageMonitor;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
/**
* Find the best Service, and bind to it.
* Handles run-time package changes.
*/
public class ServiceWatcher implements ServiceConnection {
private static final boolean D = false;
public static final String EXTRA_SERVICE_VERSION = "serviceVersion";
public static final String EXTRA_SERVICE_IS_MULTIUSER = "serviceIsMultiuser";
private final String mTag;
private final Context mContext;
private final PackageManager mPm;
private final List<HashSet<Signature>> mSignatureSets;
private final String mAction;
/**
* If mServicePackageName is not null, only this package will be searched for the service that
* implements mAction. When null, all packages in the system that matches one of the signature
* in mSignatureSets are searched.
*/
private final String mServicePackageName;
private final Runnable mNewServiceWork;
private final Handler mHandler;
private Object mLock = new Object();
// all fields below synchronized on mLock
private IBinder mBinder; // connected service
private String mPackageName; // current best package
private int mVersion = Integer.MIN_VALUE; // current best version
/**
* Whether the currently-connected service is multiuser-aware. This can change at run-time
* when switching from one version of a service to another.
*/
private boolean mIsMultiuser = false;
public static ArrayList<HashSet<Signature>> getSignatureSets(Context context,
List<String> initialPackageNames) {
PackageManager pm = context.getPackageManager();
ArrayList<HashSet<Signature>> sigSets = new ArrayList<HashSet<Signature>>();
for (int i = 0, size = initialPackageNames.size(); i < size; i++) {
String pkg = initialPackageNames.get(i);
try {
HashSet<Signature> set = new HashSet<Signature>();
Signature[] sigs = pm.getPackageInfo(pkg, PackageManager.GET_SIGNATURES).signatures;
set.addAll(Arrays.asList(sigs));
sigSets.add(set);
} catch (NameNotFoundException e) {
Log.w("ServiceWatcher", pkg + " not found");
}
}
return sigSets;
}
public ServiceWatcher(Context context, String logTag, String action,
int overlaySwitchResId, int defaultServicePackageNameResId,
int initialPackageNamesResId, Runnable newServiceWork,
Handler handler) {
mContext = context;
mTag = logTag;
mAction = action;
mPm = mContext.getPackageManager();
mNewServiceWork = newServiceWork;
mHandler = handler;
Resources resources = context.getResources();
// Whether to enable service overlay.
boolean enableOverlay = resources.getBoolean(overlaySwitchResId);
ArrayList<String> initialPackageNames = new ArrayList<String>();
if (enableOverlay) {
// A list of package names used to create the signatures.
String[] pkgs = resources.getStringArray(initialPackageNamesResId);
if (pkgs != null) initialPackageNames.addAll(Arrays.asList(pkgs));
mServicePackageName = null;
if (D) Log.d(mTag, "Overlay enabled, packages=" + Arrays.toString(pkgs));
} else {
// The default package name that is searched for service implementation when overlay is
// disabled.
String servicePackageName = resources.getString(defaultServicePackageNameResId);
if (servicePackageName != null) initialPackageNames.add(servicePackageName);
mServicePackageName = servicePackageName;
if (D) Log.d(mTag, "Overlay disabled, default package=" + servicePackageName);
}
mSignatureSets = getSignatureSets(context, initialPackageNames);
}
public boolean start() {
synchronized (mLock) {
if (!bindBestPackageLocked(mServicePackageName)) return false;
}
// listen for user change
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(Intent.ACTION_USER_SWITCHED);
mContext.registerReceiverAsUser(new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (Intent.ACTION_USER_SWITCHED.equals(action)) {
switchUser();
}
}
}, UserHandle.ALL, intentFilter, null, mHandler);
// listen for relevant package changes if service overlay is enabled.
if (mServicePackageName == null) {
mPackageMonitor.register(mContext, null, UserHandle.ALL, true);
}
return true;
}
/**
* Searches and binds to the best package, or do nothing
* if the best package is already bound.
* Only checks the named package, or checks all packages if it
* is null.
* Return true if a new package was found to bind to.
*/
private boolean bindBestPackageLocked(String justCheckThisPackage) {
Intent intent = new Intent(mAction);
if (justCheckThisPackage != null) {
intent.setPackage(justCheckThisPackage);
}
List<ResolveInfo> rInfos = mPm.queryIntentServicesAsUser(intent,
PackageManager.GET_META_DATA, UserHandle.USER_OWNER);
int bestVersion = Integer.MIN_VALUE;
String bestPackage = null;
boolean bestIsMultiuser = false;
if (rInfos != null) {
for (ResolveInfo rInfo : rInfos) {
String packageName = rInfo.serviceInfo.packageName;
// check signature
try {
PackageInfo pInfo;
pInfo = mPm.getPackageInfo(packageName, PackageManager.GET_SIGNATURES);
if (!isSignatureMatch(pInfo.signatures)) {
Log.w(mTag, packageName + " resolves service " + mAction
+ ", but has wrong signature, ignoring");
continue;
}
} catch (NameNotFoundException e) {
Log.wtf(mTag, e);
continue;
}
// check metadata
int version = Integer.MIN_VALUE;
boolean isMultiuser = false;
if (rInfo.serviceInfo.metaData != null) {
version = rInfo.serviceInfo.metaData.getInt(
EXTRA_SERVICE_VERSION, Integer.MIN_VALUE);
isMultiuser = rInfo.serviceInfo.metaData.getBoolean(EXTRA_SERVICE_IS_MULTIUSER);
}
if (version > mVersion) {
bestVersion = version;
bestPackage = packageName;
bestIsMultiuser = isMultiuser;
}
}
if (D) {
Log.d(mTag, String.format("bindBestPackage for %s : %s found %d, %s", mAction,
(justCheckThisPackage == null ? ""
: "(" + justCheckThisPackage + ") "), rInfos.size(),
(bestPackage == null ? "no new best package"
: "new best package: " + bestPackage)));
}
} else {
if (D) Log.d(mTag, "Unable to query intent services for action: " + mAction);
}
if (bestPackage != null) {
bindToPackageLocked(bestPackage, bestVersion, bestIsMultiuser);
return true;
}
return false;
}
private void unbindLocked() {
String pkg;
pkg = mPackageName;
mPackageName = null;
mVersion = Integer.MIN_VALUE;
mIsMultiuser = false;
if (pkg != null) {
if (D) Log.d(mTag, "unbinding " + pkg);
mContext.unbindService(this);
}
}
private void bindToPackageLocked(String packageName, int version, boolean isMultiuser) {
unbindLocked();
Intent intent = new Intent(mAction);
intent.setPackage(packageName);
mPackageName = packageName;
mVersion = version;
mIsMultiuser = isMultiuser;
if (D) Log.d(mTag, "binding " + packageName + " (version " + version + ") ("
+ (isMultiuser ? "multi" : "single") + "-user)");
mContext.bindServiceAsUser(intent, this, Context.BIND_AUTO_CREATE | Context.BIND_NOT_FOREGROUND
| Context.BIND_NOT_VISIBLE, mIsMultiuser ? UserHandle.OWNER : UserHandle.CURRENT);
}
public static boolean isSignatureMatch(Signature[] signatures,
List<HashSet<Signature>> sigSets) {
if (signatures == null) return false;
// build hashset of input to test against
HashSet<Signature> inputSet = new HashSet<Signature>();
for (Signature s : signatures) {
inputSet.add(s);
}
// test input against each of the signature sets
for (HashSet<Signature> referenceSet : sigSets) {
if (referenceSet.equals(inputSet)) {
return true;
}
}
return false;
}
private boolean isSignatureMatch(Signature[] signatures) {
return isSignatureMatch(signatures, mSignatureSets);
}
private final PackageMonitor mPackageMonitor = new PackageMonitor() {
/**
* Called when package has been reinstalled
*/
@Override
public void onPackageUpdateFinished(String packageName, int uid) {
synchronized (mLock) {
if (packageName.equals(mPackageName)) {
// package updated, make sure to rebind
unbindLocked();
}
// Need to check all packages because this method is also called when a
// system app is uninstalled and the stock version in reinstalled.
bindBestPackageLocked(null);
}
}
@Override
public void onPackageAdded(String packageName, int uid) {
synchronized (mLock) {
if (packageName.equals(mPackageName)) {
// package updated, make sure to rebind
unbindLocked();
}
// check the new package is case it is better
bindBestPackageLocked(null);
}
}
@Override
public void onPackageRemoved(String packageName, int uid) {
synchronized (mLock) {
if (packageName.equals(mPackageName)) {
unbindLocked();
// the currently bound package was removed,
// need to search for a new package
bindBestPackageLocked(null);
}
}
}
@Override
public boolean onPackageChanged(String packageName, int uid, String[] components) {
synchronized (mLock) {
if (packageName.equals(mPackageName)) {
// service enabled or disabled, make sure to rebind
unbindLocked();
}
// the service might be disabled, need to search for a new
// package
bindBestPackageLocked(null);
}
return super.onPackageChanged(packageName, uid, components);
}
};
@Override
public void onServiceConnected(ComponentName name, IBinder binder) {
synchronized (mLock) {
String packageName = name.getPackageName();
if (packageName.equals(mPackageName)) {
if (D) Log.d(mTag, packageName + " connected");
mBinder = binder;
if (mHandler !=null && mNewServiceWork != null) {
mHandler.post(mNewServiceWork);
}
} else {
Log.w(mTag, "unexpected onServiceConnected: " + packageName);
}
}
}
@Override
public void onServiceDisconnected(ComponentName name) {
synchronized (mLock) {
String packageName = name.getPackageName();
if (D) Log.d(mTag, packageName + " disconnected");
if (packageName.equals(mPackageName)) {
mBinder = null;
}
}
}
public String getBestPackageName() {
synchronized (mLock) {
return mPackageName;
}
}
public int getBestVersion() {
synchronized (mLock) {
return mVersion;
}
}
public IBinder getBinder() {
synchronized (mLock) {
return mBinder;
}
}
public void switchUser() {
synchronized (mLock) {
if (!mIsMultiuser) {
unbindLocked();
bindBestPackageLocked(mServicePackageName);
}
}
}
}