android/android-9.0.0_r35 : android/os/ServiceManager.java

ServiceManager
https://source.android.com/
/*
 * 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 android.os;

import android.util.Log;

import com.android.internal.annotations.GuardedBy;
import com.android.internal.os.BinderInternal;
import com.android.internal.util.StatLogger;

import java.util.HashMap;
import java.util.Map;

@hide /** @hide */
public final class ServiceManager {
    private static final String TAG = "ServiceManager";
    private static final Object sLock = new Object();

    private static IServiceManager sServiceManager;

    Cache for the "well known" services, such as WM and AM.
/**
     * Cache for the "well known" services, such as WM and AM.
     */
    private static HashMap<String, IBinder> sCache = new HashMap<String, IBinder>();

    We do the "slow log" at most once every this interval.
/**
     * We do the "slow log" at most once every this interval.
     */
    private static final int SLOW_LOG_INTERVAL_MS = 5000;

    We do the "stats log" at most once every this interval.
/**
     * We do the "stats log" at most once every this interval.
     */
    private static final int STATS_LOG_INTERVAL_MS = 5000;

    Threshold in uS for a "slow" call, used on core UIDs. We use a more relax value to
avoid logspam.
/**
     * Threshold in uS for a "slow" call, used on core UIDs. We use a more relax value to
     * avoid logspam.
     */
    private static final long GET_SERVICE_SLOW_THRESHOLD_US_CORE =
            SystemProperties.getInt("debug.servicemanager.slow_call_core_ms", 10) * 1000;

    Threshold in uS for a "slow" call, used on non-core UIDs. We use a more relax value to
avoid logspam.
/**
     * Threshold in uS for a "slow" call, used on non-core UIDs. We use a more relax value to
     * avoid logspam.
     */
    private static final long GET_SERVICE_SLOW_THRESHOLD_US_NON_CORE =
            SystemProperties.getInt("debug.servicemanager.slow_call_ms", 50) * 1000;

    We log stats logging ever this many getService() calls.
/**
     * We log stats logging ever this many getService() calls.
     */
    private static final int GET_SERVICE_LOG_EVERY_CALLS_CORE =
            SystemProperties.getInt("debug.servicemanager.log_calls_core", 100);

    We log stats logging ever this many getService() calls.
/**
     * We log stats logging ever this many getService() calls.
     */
    private static final int GET_SERVICE_LOG_EVERY_CALLS_NON_CORE =
            SystemProperties.getInt("debug.servicemanager.log_calls", 200);

    @GuardedBy("sLock")
    private static int sGetServiceAccumulatedUs;

    @GuardedBy("sLock")
    private static int sGetServiceAccumulatedCallCount;

    @GuardedBy("sLock")
    private static long sLastStatsLogUptime;

    @GuardedBy("sLock")
    private static long sLastSlowLogUptime;

    @GuardedBy("sLock")
    private static long sLastSlowLogActualTime;

    interface Stats {
        int GET_SERVICE = 0;

        int COUNT = GET_SERVICE + 1;
    }

    public static final StatLogger sStatLogger = new StatLogger(new String[] {
            "getService()",
    });

    private static IServiceManager getIServiceManager() {
        if (sServiceManager != null) {
            return sServiceManager;
        }

        // Find the service manager
        sServiceManager = ServiceManagerNative
                .asInterface(Binder.allowBlocking(BinderInternal.getContextObject()));
        return sServiceManager;
    }

    Returns a reference to a service with the given name.
Params: name – the name of the service to get
Returns: a reference to the service, or null if the service doesn't exist/**
     * Returns a reference to a service with the given name.
     *
     * @param name the name of the service to get
     * @return a reference to the service, or <code>null</code> if the service doesn't exist
     */
    public static IBinder getService(String name) {
        try {
            IBinder service = sCache.get(name);
            if (service != null) {
                return service;
            } else {
                return Binder.allowBlocking(rawGetService(name));
            }
        } catch (RemoteException e) {
            Log.e(TAG, "error in getService", e);
        }
        return null;
    }

    Returns a reference to a service with the given name, or throws NullPointerException if none is found. 
@hide /**
     * Returns a reference to a service with the given name, or throws
     * {@link NullPointerException} if none is found.
     *
     * @hide
     */
    public static IBinder getServiceOrThrow(String name) throws ServiceNotFoundException {
        final IBinder binder = getService(name);
        if (binder != null) {
            return binder;
        } else {
            throw new ServiceNotFoundException(name);
        }
    }

    Place a new @a service called @a name into the service
manager.
Params: name – the name of the new service
service – the service object/**
     * Place a new @a service called @a name into the service
     * manager.
     *
     * @param name the name of the new service
     * @param service the service object
     */
    public static void addService(String name, IBinder service) {
        addService(name, service, false, IServiceManager.DUMP_FLAG_PRIORITY_DEFAULT);
    }

    Place a new @a service called @a name into the service
manager.
Params: name – the name of the new service
service – the service object
allowIsolated – set to true to allow isolated sandboxed processes
to access this service/**
     * Place a new @a service called @a name into the service
     * manager.
     *
     * @param name the name of the new service
     * @param service the service object
     * @param allowIsolated set to true to allow isolated sandboxed processes
     * to access this service
     */
    public static void addService(String name, IBinder service, boolean allowIsolated) {
        addService(name, service, allowIsolated, IServiceManager.DUMP_FLAG_PRIORITY_DEFAULT);
    }

    Place a new @a service called @a name into the service
manager.
Params: name – the name of the new service
service – the service object
allowIsolated – set to true to allow isolated sandboxed processes
dumpPriority – supported dump priority levels as a bitmask
to access this service/**
     * Place a new @a service called @a name into the service
     * manager.
     *
     * @param name the name of the new service
     * @param service the service object
     * @param allowIsolated set to true to allow isolated sandboxed processes
     * @param dumpPriority supported dump priority levels as a bitmask
     * to access this service
     */
    public static void addService(String name, IBinder service, boolean allowIsolated,
            int dumpPriority) {
        try {
            getIServiceManager().addService(name, service, allowIsolated, dumpPriority);
        } catch (RemoteException e) {
            Log.e(TAG, "error in addService", e);
        }
    }

    Retrieve an existing service called @a name from the
service manager.  Non-blocking.
/**
     * Retrieve an existing service called @a name from the
     * service manager.  Non-blocking.
     */
    public static IBinder checkService(String name) {
        try {
            IBinder service = sCache.get(name);
            if (service != null) {
                return service;
            } else {
                return Binder.allowBlocking(getIServiceManager().checkService(name));
            }
        } catch (RemoteException e) {
            Log.e(TAG, "error in checkService", e);
            return null;
        }
    }

    Return a list of all currently running services.
Returns: an array of all currently running services, or null in
case of an exception/**
     * Return a list of all currently running services.
     * @return an array of all currently running services, or <code>null</code> in
     * case of an exception
     */
    public static String[] listServices() {
        try {
            return getIServiceManager().listServices(IServiceManager.DUMP_FLAG_PRIORITY_ALL);
        } catch (RemoteException e) {
            Log.e(TAG, "error in listServices", e);
            return null;
        }
    }

    This is only intended to be called when the process is first being brought
up and bound by the activity manager. There is only one thread in the process
at that time, so no locking is done.
Params: cache – the cache of service references
@hide /**
     * This is only intended to be called when the process is first being brought
     * up and bound by the activity manager. There is only one thread in the process
     * at that time, so no locking is done.
     *
     * @param cache the cache of service references
     * @hide
     */
    public static void initServiceCache(Map<String, IBinder> cache) {
        if (sCache.size() != 0) {
            throw new IllegalStateException("setServiceCache may only be called once");
        }
        sCache.putAll(cache);
    }

    Exception thrown when no service published for given name. This might be
thrown early during boot before certain services have published
themselves.
@hide /**
     * Exception thrown when no service published for given name. This might be
     * thrown early during boot before certain services have published
     * themselves.
     *
     * @hide
     */
    public static class ServiceNotFoundException extends Exception {
        public ServiceNotFoundException(String name) {
            super("No service published for: " + name);
        }
    }

    private static IBinder rawGetService(String name) throws RemoteException {
        final long start = sStatLogger.getTime();

        final IBinder binder = getIServiceManager().getService(name);

        final int time = (int) sStatLogger.logDurationStat(Stats.GET_SERVICE, start);

        final int myUid = Process.myUid();
        final boolean isCore = UserHandle.isCore(myUid);

        final long slowThreshold = isCore
                ? GET_SERVICE_SLOW_THRESHOLD_US_CORE
                : GET_SERVICE_SLOW_THRESHOLD_US_NON_CORE;

        synchronized (sLock) {
            sGetServiceAccumulatedUs += time;
            sGetServiceAccumulatedCallCount++;

            final long nowUptime = SystemClock.uptimeMillis();

            // Was a slow call?
            if (time >= slowThreshold) {
                // We do a slow log:
                // - At most once in every SLOW_LOG_INTERVAL_MS
                // - OR it was slower than the previously logged slow call.
                if ((nowUptime > (sLastSlowLogUptime + SLOW_LOG_INTERVAL_MS))
                        || (sLastSlowLogActualTime < time)) {
                    EventLogTags.writeServiceManagerSlow(time / 1000, name);

                    sLastSlowLogUptime = nowUptime;
                    sLastSlowLogActualTime = time;
                }
            }

            // Every GET_SERVICE_LOG_EVERY_CALLS calls, log the total time spent in getService().

            final int logInterval = isCore
                    ? GET_SERVICE_LOG_EVERY_CALLS_CORE
                    : GET_SERVICE_LOG_EVERY_CALLS_NON_CORE;

            if ((sGetServiceAccumulatedCallCount >= logInterval)
                    && (nowUptime >= (sLastStatsLogUptime + STATS_LOG_INTERVAL_MS))) {

                EventLogTags.writeServiceManagerStats(
                        sGetServiceAccumulatedCallCount, // Total # of getService() calls.
                        sGetServiceAccumulatedUs / 1000, // Total time spent in getService() calls.
                        (int) (nowUptime - sLastStatsLogUptime)); // Uptime duration since last log.
                sGetServiceAccumulatedCallCount = 0;
                sGetServiceAccumulatedUs = 0;
                sLastStatsLogUptime = nowUptime;
            }
        }
        return binder;
    }
}
Params:	name – the name of the service to get
Returns:	a reference to the service, or `null` if the service doesn't exist
/

android/ android-9.0.0_r35/ android/os/ServiceManager.java
