Android P系统设置之SettingsProvider源码分析

雨点打透心脏的1/2处 2024-04-18 22:56 32阅读 0赞

相关源码：  
\\frameworks\\base\\services\\java\\com\\android\\server\\SystemServer.java  
\\frameworks\\base\\services\\core\\java\\com\\android\\server\\am\\ActivityManagerService.java  
\\frameworks\\base\\packages\\SettingsProvider\\src\\com\\android\\providers\\settings\\SettingsProvider.java

\\frameworks\\base\\packages\\SettingsProvider\\res\\values\\defaults.xml

SettingsProvider是系统设置的内容提供者。

它将设置类型分类三类：

*  Global，全局，对系统中所有用户公开，第三方App没有写权限
 *  Secure，安全相关的用户偏好设置，第三方App没有写权限
 *  System，用户偏好系统设置

在最新android 9.0系统中，数据存储由原来的数据库settings.db，转移保存到xml中：

*  data/system/users/0/settings\_global.xml
 *  data/system/users/userid/settings\_system.xml
 *  data/system/users/userid/settings\_secure.xml

settings.db删除不再使用。

## SettingsProvider启动 ##

\\frameworks\\base\\services\\java\\com\\android\\server\\SystemServer.java  
在installSystemProviders()中启动了SettingsProvider

private void startOtherServices() { 
    	//省略一部分代码
    	//...
    	
    	traceBeginAndSlog("InstallSystemProviders");
    	mActivityManagerService.installSystemProviders();
    	// Now that SettingsProvider is ready, reactivate SQLiteCompatibilityWalFlags
    	SQLiteCompatibilityWalFlags.reset();
    	traceEnd();
    	
    	//省略一部分代码
    	//...
    }

\\frameworks\\base\\services\\core\\java\\com\\android\\server\\am\\ActivityManagerService.java  
installSystemProviders()中三个关键的步骤，1,2,3

public final void installSystemProviders() { 
    	// 1、获取系统中所有的Provider，最终通过调用包管理PackageManagerService中的queryContentProviders()方法来查询所有的Provider
        List<ProviderInfo> providers;
        synchronized (this) { 
            ProcessRecord app = mProcessNames.get("system", SYSTEM_UID);
            providers = generateApplicationProvidersLocked(app);
            if (providers != null) { 
                for (int i=providers.size()-1; i>=0; i--) { 
                    ProviderInfo pi = (ProviderInfo)providers.get(i);
                    if ((pi.applicationInfo.flags&ApplicationInfo.FLAG_SYSTEM) == 0) { 
                        Slog.w(TAG, "Not installing system proc provider " + pi.name
                                + ": not system .apk");
                        providers.remove(i);
                    }
                }
            }
        }
    	// 2、调用ActivityThread中的installSystemProviders来完成Provider的安装，包括SettingsProvider
        if (providers != null) { 
            mSystemThread.installSystemProviders(providers);
        }
    
        synchronized (this) { 
            mSystemProvidersInstalled = true;
        }
    
        mConstants.start(mContext.getContentResolver());
        mCoreSettingsObserver = new CoreSettingsObserver(this);
        mFontScaleSettingObserver = new FontScaleSettingObserver();
        mDevelopmentSettingsObserver = new DevelopmentSettingsObserver();
        GlobalSettingsToPropertiesMapper.start(mContext.getContentResolver());
    
    	// 3、Provider启动完成
        // Now that the settings provider is published we can consider sending
        // in a rescue party.
        RescueParty.onSettingsProviderPublished(mContext);
    
        //mUsageStatsService.monitorPackages();
    }

其中，第二步中，installSystemProviders()会调用到SettingsProvider中的onCreate()方法。

\\frameworks\\base\\packages\\SettingsProvider\\src\\com\\android\\providers\\settings\\SettingsProvider.java

@Override
    public boolean onCreate() { 
        Settings.setInSystemServer();
    
        // fail to boot if there're any backed up settings that don't have a non-null validator
        ensureAllBackedUpSystemSettingsHaveValidators();
        ensureAllBackedUpGlobalSettingsHaveValidators();
        ensureAllBackedUpSecureSettingsHaveValidators();
    
        synchronized (mLock) { 
            mUserManager = UserManager.get(getContext());
            mUserManagerInternal = LocalServices.getService(UserManagerInternal.class);
            mPackageManager = AppGlobals.getPackageManager();
            mHandlerThread = new HandlerThread(LOG_TAG,
                    Process.THREAD_PRIORITY_BACKGROUND);
            mHandlerThread.start();
            mHandler = new Handler(mHandlerThread.getLooper());
            mSettingsRegistry = new SettingsRegistry();
        }
        mHandler.post(() -> { 
            registerBroadcastReceivers();
            startWatchingUserRestrictionChanges();
        });
        ServiceManager.addService("settings", new SettingsService(this));
        return true;
    }

其中，关键的部分是：mSettingsRegistry = new SettingsRegistry();

final class SettingsRegistry { 
        private static final String DROPBOX_TAG_USERLOG = "restricted_profile_ssaid";
        private static final String SETTINGS_FILE_GLOBAL = "settings_global.xml";
        private static final String SETTINGS_FILE_SYSTEM = "settings_system.xml";
        private static final String SETTINGS_FILE_SECURE = "settings_secure.xml";
        private static final String SETTINGS_FILE_SSAID = "settings_ssaid.xml";
        private static final String SSAID_USER_KEY = "userkey";
    
        public SettingsRegistry() { 
            mHandler = new MyHandler(getContext().getMainLooper());
            // 1、对xml的修改做版本管理
            mGenerationRegistry = new GenerationRegistry(mLock);
            // 2、创建Backup，做系统备份
            mBackupManager = new BackupManager(getContext());
            // 3、迁移所有的系统设置数据
            migrateAllLegacySettingsIfNeeded();
            syncSsaidTableOnStart();
        }
    
        private void migrateAllLegacySettingsIfNeeded() { 
            synchronized (mLock) { 
                final int key = makeKey(SETTINGS_TYPE_GLOBAL, UserHandle.USER_SYSTEM);.
                // 1、判断settings_global.xml是否存在，如果不存怎，就返回，不用做数据迁移
                // 所以，settings_global.xml一般都是存在，只有升级后系统第一次启动的时候才会不存在，
                // 数据迁移，只会发生在系统升级后第一次启动的情况
                File globalFile = getSettingsFile(key);
                if (SettingsState.stateFileExists(globalFile)) { 
                    return;
                }
    
                mSettingsCreationBuildId = Build.ID;
    
                final long identity = Binder.clearCallingIdentity();
                try { 
                	// 2、获取系统中所有的用户(多用户，一般user0)
                    List<UserInfo> users = mUserManager.getUsers(true);
    
                    final int userCount = users.size();
                    for (int i = 0; i < userCount; i++) { 
                        final int userId = users.get(i).id;
    					// 3、关键代码，通过DatabaseHelper类创建数据库settings.db，并使用默认设置对数据库表数据初始化
                        DatabaseHelper dbHelper = new DatabaseHelper(getContext(), userId);
                        SQLiteDatabase database = dbHelper.getWritableDatabase();
                        migrateLegacySettingsForUserLocked(dbHelper, database, userId);
                        
    					// 4、关键代码，生成和初始化xml文件
                        // Upgrade to the latest version.
                        UpgradeController upgrader = new UpgradeController(userId);
                        upgrader.upgradeIfNeededLocked();
    
                        // Drop from memory if not a running user.
                        if (!mUserManager.isUserRunning(new UserHandle(userId))) { 
                            removeUserStateLocked(userId, false);
                        }
                    }
                } finally { 
                    Binder.restoreCallingIdentity(identity);
                }
            }
        }
    }

重点，migrateLegacySettingsForUserLocked()和upgradeIfNeededLocked()。

## DatabaseHelper类 ##

SettingsRegistry类中的migrateAllLegacySettingsIfNeeded中执行了DatabaseHelper去创建数据库settings.db.  
DatabaseHelper dbHelper = new DatabaseHelper(getContext(), userId);  
SQLiteDatabase database = dbHelper.getWritableDatabase();  
DatabaseHelper()中执行了dbNameForUser()，SQLiteOpenHelper 创建了数据库settings.db。  
在settings.db数据库创建后，回调onCreate函数。onCreate()中,创建了数据的表。

class DatabaseHelper extends SQLiteOpenHelper { 
    
    	private static final String DATABASE_NAME = "settings.db";
    
    	public DatabaseHelper(Context context, int userHandle) { 
          super(context, dbNameForUser(userHandle), null, DATABASE_VERSION);
          mContext = context;
          mUserHandle = userHandle;
      	}
    
    	static String dbNameForUser(final int userHandle) { 
         // The owner gets the unadorned db name;
         if (userHandle == UserHandle.USER_SYSTEM) { 
             return DATABASE_NAME;
         } else { 
             // Place the database in the user-specific data tree so that it's
             // cleaned up automatically when the user is deleted.
             File databaseFile = new File(
                     Environment.getUserSystemDirectory(userHandle), DATABASE_NAME);
             // If databaseFile doesn't exist, database can be kept in memory. It's safe because the
             // database will be migrated and disposed of immediately after onCreate finishes
             if (!databaseFile.exists()) { 
                 Log.i(TAG, "No previous database file exists - running in in-memory mode");
                 return null;
             }
             return databaseFile.getPath();
         }
    	}
    
    	@Override
    	public void onCreate(SQLiteDatabase db) { 
    		
    	   db.execSQL("CREATE TABLE system (" +
    	               "_id INTEGER PRIMARY KEY AUTOINCREMENT," +
    	               "name TEXT UNIQUE ON CONFLICT REPLACE," +
    	               "value TEXT" +
    	               ");");
    	   db.execSQL("CREATE INDEX systemIndex1 ON system (name);");
    	
    		// 1、创建表，createSecureTable，Secure数据表
    	   createSecureTable(db);
    	
    	   // 2、创建表，createGlobalTable，Global数据表
    	   // Only create the global table for the singleton 'owner/system' user
    	   if (mUserHandle == UserHandle.USER_SYSTEM) { 
    	       createGlobalTable(db);
    	   }
    	
    	   db.execSQL("CREATE TABLE bluetooth_devices (" +
    	               "_id INTEGER PRIMARY KEY," +
    	               "name TEXT," +
    	               "addr TEXT," +
    	               "channel INTEGER," +
    	               "type INTEGER" +
    	               ");");
    	
    	   db.execSQL("CREATE TABLE bookmarks (" +
    	               "_id INTEGER PRIMARY KEY," +
    	               "title TEXT," +
    	               "folder TEXT," +
    	               "intent TEXT," +
    	               "shortcut INTEGER," +
    	               "ordering INTEGER" +
    	               ");");
    	
    	   db.execSQL("CREATE INDEX bookmarksIndex1 ON bookmarks (folder);");
    	   db.execSQL("CREATE INDEX bookmarksIndex2 ON bookmarks (shortcut);");
    	
    	   // Populate bookmarks table with initial bookmarks
    	   boolean onlyCore = false;
    	   try { 
    	       onlyCore = IPackageManager.Stub.asInterface(ServiceManager.getService(
    	               "package")).isOnlyCoreApps();
    	   } catch (RemoteException e) { 
    	   }
    	   if (!onlyCore) { 
    	       loadBookmarks(db);
    	   }
    	
    		// 3、默认数据填充数据库
    	   // Load initial volume levels into DB
    	   loadVolumeLevels(db);
    	
    		// 4、默认数据填充数据库
    	   // Load inital settings values
    	   loadSettings(db);
    	}
    }

## Settings.db数据迁移到xml中 ##

还是继续看SettingsRegistry 中的migrateLegacySettingsForUserLocked()和upgradeIfNeededLocked()，

SettingsProvider中几个数据类型的定义：

//SettingsState.java中
    public static final int SETTINGS_TYPE_GLOBAL = 0;
    public static final int SETTINGS_TYPE_SYSTEM = 1;
    public static final int SETTINGS_TYPE_SECURE = 2;
    public static final int SETTINGS_TYPE_SSAID = 3;
    public static final int SETTINGS_TYPE_MASK = 0xF0000000;
    public static final int SETTINGS_TYPE_SHIFT = 28;
    //SettingsProvider.java中
    public static final int SETTINGS_TYPE_GLOBAL = SettingsState.SETTINGS_TYPE_GLOBAL;
    public static final int SETTINGS_TYPE_SYSTEM = SettingsState.SETTINGS_TYPE_SYSTEM;
    public static final int SETTINGS_TYPE_SECURE = SettingsState.SETTINGS_TYPE_SECURE;
    public static final int SETTINGS_TYPE_SSAID = SettingsState.SETTINGS_TYPE_SSAID;

final class SettingsRegistry { 
      private void migrateLegacySettingsForUserLocked(DatabaseHelper dbHelper, SQLiteDatabase database, int userId) { 
         // 1、处理System数据， 
         // Move over the system settings.
         final int systemKey = makeKey(SETTINGS_TYPE_SYSTEM, userId);
         //生成对应的SettingsState对象保存在mSettingsStates中，生成settings_system.xml
         ensureSettingsStateLocked(systemKey);
         SettingsState systemSettings = mSettingsStates.get(systemKey);
         //数据迁移，将settings.db的数据迁移到settings_system.xml中
         migrateLegacySettingsLocked(systemSettings, database, TABLE_SYSTEM);
         systemSettings.persistSyncLocked();
         
         // 2、处理Secure 数据，
         // Move over the secure settings.
         // Do this after System settings, since this is the first thing we check when deciding
         // to skip over migration from db to xml for a secondary user.
         final int secureKey = makeKey(SETTINGS_TYPE_SECURE, userId);
         //生成对应的SettingsState对象保存在mSettingsStates中，生成settings_secure.xml
         ensureSettingsStateLocked(secureKey);
         SettingsState secureSettings = mSettingsStates.get(secureKey);
         //数据迁移，将settings.db的数据迁移到settings_secure.xml中
         migrateLegacySettingsLocked(secureSettings, database, TABLE_SECURE);
         ensureSecureSettingAndroidIdSetLocked(secureSettings);
         secureSettings.persistSyncLocked();
         // 3、处理Global 数据， 
         // Move over the global settings if owner.
         // Do this last, since this is the first thing we check when deciding
         // to skip over migration from db to xml for owner user.
         if (userId == UserHandle.USER_SYSTEM) { 
             final int globalKey = makeKey(SETTINGS_TYPE_GLOBAL, userId);
             //生成对应的SettingsState对象保存在mSettingsStates中，生成settings_global.xml
             ensureSettingsStateLocked(globalKey);
             SettingsState globalSettings = mSettingsStates.get(globalKey);
             //数据迁移，将settings.db的数据迁移到settings_global.xml中
             migrateLegacySettingsLocked(globalSettings, database, TABLE_GLOBAL);
             // If this was just created
             if (mSettingsCreationBuildId != null) { 
                 globalSettings.insertSettingLocked(Settings.Global.DATABASE_CREATION_BUILDID,
                         mSettingsCreationBuildId, null, true,
                         SettingsState.SYSTEM_PACKAGE_NAME);
             }
             globalSettings.persistSyncLocked();
         }
    
    	//数据迁移完成后，是否删除settings.db，或者做一个备份
         // Drop the database as now all is moved and persisted.
         if (DROP_DATABASE_ON_MIGRATION) { 
             dbHelper.dropDatabase();
         } else { 
             dbHelper.backupDatabase();
         }
      }
    
      //ensureSettingsStateLocked是一个重要的方法，给每一个数据类型key，穿件一个对应的SettingsState对象并保存在mSettingsStates
      private void ensureSettingsStateLocked(int key) { 
          if (mSettingsStates.get(key) == null) { 
              final int maxBytesPerPackage = getMaxBytesPerPackageForType(getTypeFromKey(key));
              SettingsState settingsState = new SettingsState(getContext(), mLock,
                      getSettingsFile(key), key, maxBytesPerPackage, mHandlerThread.getLooper());
              mSettingsStates.put(key, settingsState);
          }
      }
    
    }

SettingsState中，persistSyncLocked()方法最终完成xml的数据写入。

DatabaseHelper中settings.db的数据默认值来自于\\frameworks\\base\\packages\\SettingsProvider\\res\\values\\defaults.xml。

具体是在loadSecureSettings()，loadSetting()方法中加载的。

## Provider数据读写 ##

写数据调用接口的方法：

// Add a persistent setting to allow other apps to know the device has been provisioned.
    Settings.Secure.putInt(getContentResolver(), Settings.Secure.DEVICE_PROVISIONED, 1);
            
    // Enable the GPS.
    // Not needed since this SDK will contain the Settings app.
    Settings.Secure.putString(getContentResolver(),Settings.Secure.LOCATION_PROVIDERS_ALLOWED, LocationManager.GPS_PROVIDER);

读数据调用接口的方法：

Settings.Secure.getint(mContext.getContentResolver(),Settings.Secure.DEVICE_PROVISIONED);
    Settings.Secure.getString(mContext.getContentResolver(),Settings.Secure.LOCATION_PROVIDERS_ALLOWED);

## 调式 ##

1、在以下目录可以看到以下保存在xml中的值。

*  data/system/users/0/settings\_global.xml
 *  data/system/users/userid/settings\_system.xml
 *  data/system/users/userid/settings\_secure.xml

2、将private static final boolean DROP\_DATABASE\_ON\_MIGRATION = false;设置为false,可以保存settings.db数据。  
为true时会删除掉。

3、在DatabaseHelper类中loadSetting()方法打印数据：

private void loadSetting(SQLiteStatement stmt, String key, Object value) { 
    	Log.i(TAG, "sunxiaolin,loadSetting,key=" + key + ", value=" + value.toString());
        stmt.bindString(1, key);
        stmt.bindString(2, value.toString());
        stmt.execute();
    }

2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=screen\_brightness, value=102  
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=screen\_brightness\_for\_vr, value=86  
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=screen\_brightness\_mode, value=0  
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=accelerometer\_rotation, value=0  
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=haptic\_feedback\_enabled, value=1  
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=notification\_light\_pulse, value=1  
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=dtmf\_tone, value=1  
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=sound\_effects\_enabled, value=1  
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=haptic\_feedback\_enabled, value=1  
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=lockscreen\_sounds\_enabled, value=1  
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=pointer\_speed, value=0  
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=location\_providers\_allowed, value=gps,network  
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=mock\_location, value=1  
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=backup\_enabled, value=0  
2019-09-12 15:08:29.273 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=backup\_transport, value=android/com.android.internal.backup.LocalTransport  
2019-09-12 15:08:29.273 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=mount\_play\_not\_snd, value=1  
2019-09-12 15:08:29.273 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=mount\_ums\_autostart, value=0