Nick Pelly | 6fa9ad4 | 2012-07-16 12:18:23 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2012 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.server; |
| 18 | |
| 19 | import android.content.ComponentName; |
| 20 | import android.content.Context; |
| 21 | import android.content.Intent; |
| 22 | import android.content.ServiceConnection; |
| 23 | import android.content.pm.PackageInfo; |
| 24 | import android.content.pm.PackageManager; |
| 25 | import android.content.pm.PackageManager.NameNotFoundException; |
| 26 | import android.content.pm.ResolveInfo; |
| 27 | import android.content.pm.Signature; |
| 28 | import android.os.Handler; |
| 29 | import android.os.IBinder; |
| 30 | import android.util.Log; |
| 31 | |
| 32 | import com.android.internal.content.PackageMonitor; |
| 33 | |
| 34 | import java.util.ArrayList; |
| 35 | import java.util.Arrays; |
| 36 | import java.util.HashSet; |
| 37 | import java.util.List; |
| 38 | |
| 39 | /** |
| 40 | * Find the best Service, and bind to it. |
| 41 | * Handles run-time package changes. |
| 42 | */ |
| 43 | public class ServiceWatcher implements ServiceConnection { |
| 44 | private static final boolean D = false; |
| 45 | private static final String EXTRA_VERSION = "version"; |
| 46 | |
| 47 | private final String mTag; |
| 48 | private final Context mContext; |
| 49 | private final PackageManager mPm; |
| 50 | private final List<HashSet<Signature>> mSignatureSets; |
| 51 | private final String mAction; |
| 52 | private final Runnable mNewServiceWork; |
| 53 | private final Handler mHandler; |
| 54 | |
| 55 | private Object mLock = new Object(); |
| 56 | |
| 57 | // all fields below synchronized on mLock |
| 58 | private IBinder mBinder; // connected service |
| 59 | private String mPackageName; // current best package |
| 60 | private int mVersion; // current best version |
| 61 | |
| 62 | public ServiceWatcher(Context context, String logTag, String action, |
| 63 | List<String> initialPackageNames, Runnable newServiceWork, Handler handler) { |
| 64 | mContext = context; |
| 65 | mTag = logTag; |
| 66 | mAction = action; |
| 67 | mPm = mContext.getPackageManager(); |
| 68 | mNewServiceWork = newServiceWork; |
| 69 | mHandler = handler; |
| 70 | |
| 71 | mSignatureSets = new ArrayList<HashSet<Signature>>(); |
| 72 | for (int i=0; i < initialPackageNames.size(); i++) { |
| 73 | String pkg = initialPackageNames.get(i); |
| 74 | HashSet<Signature> set = new HashSet<Signature>(); |
| 75 | try { |
| 76 | Signature[] sigs = |
| 77 | mPm.getPackageInfo(pkg, PackageManager.GET_SIGNATURES).signatures; |
| 78 | set.addAll(Arrays.asList(sigs)); |
| 79 | mSignatureSets.add(set); |
| 80 | } catch (NameNotFoundException e) { |
| 81 | Log.w(logTag, pkg + " not found"); |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | } |
| 86 | |
| 87 | public boolean start() { |
| 88 | if (!bindBestPackage(null)) return false; |
| 89 | |
| 90 | mPackageMonitor.register(mContext, null, true); |
| 91 | return true; |
| 92 | } |
| 93 | |
| 94 | /** |
| 95 | * Searches and binds to the best package, or do nothing |
| 96 | * if the best package is already bound. |
| 97 | * Only checks the named package, or checks all packages if it |
| 98 | * is null. |
| 99 | * Return true if a new package was found to bind to. |
| 100 | */ |
| 101 | private boolean bindBestPackage(String justCheckThisPackage) { |
| 102 | Intent intent = new Intent(mAction); |
| 103 | if (justCheckThisPackage != null) { |
| 104 | intent.setPackage(justCheckThisPackage); |
| 105 | } |
| 106 | List<ResolveInfo> rInfos = mPm.queryIntentServices(new Intent(mAction), |
| 107 | PackageManager.GET_META_DATA); |
| 108 | int bestVersion = Integer.MIN_VALUE; |
| 109 | String bestPackage = null; |
| 110 | for (ResolveInfo rInfo : rInfos) { |
| 111 | String packageName = rInfo.serviceInfo.packageName; |
| 112 | |
| 113 | // check signature |
| 114 | try { |
| 115 | PackageInfo pInfo; |
| 116 | pInfo = mPm.getPackageInfo(packageName, PackageManager.GET_SIGNATURES); |
| 117 | if (!isSignatureMatch(pInfo.signatures)) { |
| 118 | Log.w(mTag, packageName + " resolves service " + mAction + |
| 119 | ", but has wrong signature, ignoring"); |
| 120 | continue; |
| 121 | } |
| 122 | } catch (NameNotFoundException e) { |
| 123 | Log.wtf(mTag, e); |
| 124 | continue; |
| 125 | } |
| 126 | |
| 127 | // check version |
| 128 | int version = 0; |
| 129 | if (rInfo.serviceInfo.metaData != null) { |
| 130 | version = rInfo.serviceInfo.metaData.getInt(EXTRA_VERSION, 0); |
| 131 | } |
| 132 | if (version > mVersion) { |
| 133 | bestVersion = version; |
| 134 | bestPackage = packageName; |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | if (D) Log.d(mTag, String.format("bindBestPackage %s found %d, %s", |
| 139 | (justCheckThisPackage == null ? "" : "(" + justCheckThisPackage + ") "), |
| 140 | rInfos.size(), |
| 141 | (bestPackage == null ? "no new best package" : "new best packge: " + bestPackage))); |
| 142 | |
| 143 | if (bestPackage != null) { |
| 144 | bindToPackage(bestPackage, bestVersion); |
| 145 | return true; |
| 146 | } |
| 147 | return false; |
| 148 | } |
| 149 | |
| 150 | private void unbind() { |
| 151 | String pkg; |
| 152 | synchronized (mLock) { |
| 153 | pkg = mPackageName; |
| 154 | mPackageName = null; |
| 155 | mVersion = Integer.MIN_VALUE; |
| 156 | } |
| 157 | if (pkg != null) { |
| 158 | if (D) Log.d(mTag, "unbinding " + pkg); |
| 159 | mContext.unbindService(this); |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | private void bindToPackage(String packageName, int version) { |
| 164 | unbind(); |
| 165 | Intent intent = new Intent(mAction); |
| 166 | intent.setPackage(packageName); |
| 167 | synchronized (mLock) { |
| 168 | mPackageName = packageName; |
| 169 | mVersion = version; |
| 170 | } |
| 171 | if (D) Log.d(mTag, "binding " + packageName + " (version " + version + ")"); |
| 172 | mContext.bindService(intent, this, Context.BIND_AUTO_CREATE | Context.BIND_NOT_FOREGROUND |
| 173 | | Context.BIND_ALLOW_OOM_MANAGEMENT); |
| 174 | } |
| 175 | |
| 176 | private boolean isSignatureMatch(Signature[] signatures) { |
| 177 | if (signatures == null) return false; |
| 178 | |
| 179 | // build hashset of input to test against |
| 180 | HashSet<Signature> inputSet = new HashSet<Signature>(); |
| 181 | for (Signature s : signatures) { |
| 182 | inputSet.add(s); |
| 183 | } |
| 184 | |
| 185 | // test input against each of the signature sets |
| 186 | for (HashSet<Signature> referenceSet : mSignatureSets) { |
| 187 | if (referenceSet.equals(inputSet)) { |
| 188 | return true; |
| 189 | } |
| 190 | } |
| 191 | return false; |
| 192 | } |
| 193 | |
| 194 | private final PackageMonitor mPackageMonitor = new PackageMonitor() { |
| 195 | /** |
| 196 | * Called when package has been reinstalled |
| 197 | */ |
| 198 | @Override |
| 199 | public void onPackageUpdateFinished(String packageName, int uid) { |
| 200 | if (packageName.equals(mPackageName)) { |
| 201 | // package updated, make sure to rebind |
| 202 | unbind(); |
| 203 | } |
| 204 | // check the updated package in case it is better |
| 205 | bindBestPackage(packageName); |
| 206 | } |
| 207 | |
| 208 | @Override |
| 209 | public void onPackageAdded(String packageName, int uid) { |
| 210 | if (packageName.equals(mPackageName)) { |
| 211 | // package updated, make sure to rebind |
| 212 | unbind(); |
| 213 | } |
| 214 | // check the new package is case it is better |
| 215 | bindBestPackage(packageName); |
| 216 | } |
| 217 | |
| 218 | @Override |
| 219 | public void onPackageRemoved(String packageName, int uid) { |
| 220 | if (packageName.equals(mPackageName)) { |
| 221 | unbind(); |
| 222 | // the currently bound package was removed, |
| 223 | // need to search for a new package |
| 224 | bindBestPackage(null); |
| 225 | } |
| 226 | } |
| 227 | }; |
| 228 | |
| 229 | @Override |
| 230 | public void onServiceConnected(ComponentName name, IBinder binder) { |
| 231 | synchronized (mLock) { |
| 232 | String packageName = name.getPackageName(); |
| 233 | if (packageName.equals(mPackageName)) { |
| 234 | if (D) Log.d(mTag, packageName + " connected"); |
| 235 | mBinder = binder; |
| 236 | if (mHandler !=null && mNewServiceWork != null) { |
| 237 | mHandler.post(mNewServiceWork); |
| 238 | } |
| 239 | } else { |
| 240 | Log.w(mTag, "unexpected onServiceConnected: " + packageName); |
| 241 | } |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | @Override |
| 246 | public void onServiceDisconnected(ComponentName name) { |
| 247 | synchronized (mLock) { |
| 248 | String packageName = name.getPackageName(); |
| 249 | if (D) Log.d(mTag, packageName + " disconnected"); |
| 250 | |
| 251 | if (packageName.equals(mPackageName)) { |
| 252 | mBinder = null; |
| 253 | } |
| 254 | } |
| 255 | } |
| 256 | |
| 257 | public String getBestPackageName() { |
| 258 | synchronized (mLock) { |
| 259 | return mPackageName; |
| 260 | } |
| 261 | } |
| 262 | |
| 263 | public int getBestVersion() { |
| 264 | synchronized (mLock) { |
| 265 | return mVersion; |
| 266 | } |
| 267 | } |
| 268 | |
| 269 | public IBinder getBinder() { |
| 270 | synchronized (mLock) { |
| 271 | return mBinder; |
| 272 | } |
| 273 | } |
| 274 | } |