/*
* 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.os;
import android.content.pm.PackageManager;
import android.os.Binder;
import android.os.IBinder;
import android.os.ISchedulingPolicyService;
import android.os.Process;
import android.os.RemoteException;
import android.util.Log;
import com.android.server.SystemServerInitThreadPool;
/**
* The implementation of the scheduling policy service interface.
*
* @hide
*/
public class SchedulingPolicyService extends ISchedulingPolicyService.Stub {
private static final String TAG = "SchedulingPolicyService";
// Minimum and maximum values allowed for requestPriority parameter prio
private static final int PRIORITY_MIN = 1;
private static final int PRIORITY_MAX = 3;
private static final String[] MEDIA_PROCESS_NAMES = new String[] {
"media.codec", // vendor/bin/hw/android.hardware.media.omx@1.0-service
};
private final IBinder.DeathRecipient mDeathRecipient = new IBinder.DeathRecipient() {
@Override
public void binderDied() {
requestCpusetBoost(false /*enable*/, null /*client*/);
}
};
// Current process that received a cpuset boost
private int mBoostedPid = -1;
// Current client registered to the death recipient
private IBinder mClient;
public SchedulingPolicyService() {
// system_server (our host) could have crashed before. The app may not survive
// it, but mediaserver/media.codec could have, and mediaserver probably tried
// to disable the boost while we were dead.
// We do a restore of media.codec to default cpuset upon service restart to
// catch this case. We can't leave media.codec in boosted state, because we've
// lost the death recipient of mClient from mediaserver after the restart,
// if mediaserver dies in the future we won't have a notification to reset.
// (Note that if mediaserver thinks we're in boosted state before the crash,
// the state could go out of sync temporarily until mediaserver enables/disable
// boost next time, but this won't be a big issue.)
SystemServerInitThreadPool.get().submit(() -> {
synchronized (mDeathRecipient) {
// only do this if we haven't already got a request to boost.
if (mBoostedPid == -1) {
int[] nativePids = Process.getPidsForCommands(MEDIA_PROCESS_NAMES);
if (nativePids != null && nativePids.length == 1) {
mBoostedPid = nativePids[0];
disableCpusetBoost(nativePids[0]);
}
}
}
}, TAG + ".<init>");
}
// TODO(b/35196900) We should pass the period in time units, rather
// than a fixed priority number.
public int requestPriority(int pid, int tid, int prio, boolean isForApp) {
//Log.i(TAG, "requestPriority(pid=" + pid + ", tid=" + tid + ", prio=" + prio + ")");
// Verify that the caller uid is permitted, priority is in range,
// and that the callback thread specified by app belongs to the app that
// called mediaserver or audioserver.
// Once we've verified that the caller uid is permitted, we can trust the pid but
// we can't trust the tid. No need to explicitly check for pid == 0 || tid == 0,
// since if not the case then the getThreadGroupLeader() test will also fail.
if (!isPermitted() || prio < PRIORITY_MIN ||
prio > PRIORITY_MAX || Process.getThreadGroupLeader(tid) != pid) {
return PackageManager.PERMISSION_DENIED;
}
if (Binder.getCallingUid() != Process.BLUETOOTH_UID) {
try {
// make good use of our CAP_SYS_NICE capability
Process.setThreadGroup(tid, !isForApp ?
Process.THREAD_GROUP_AUDIO_SYS : Process.THREAD_GROUP_RT_APP);
} catch (RuntimeException e) {
Log.e(TAG, "Failed setThreadGroup: " + e);
return PackageManager.PERMISSION_DENIED;
}
}
try {
// must be in this order or it fails the schedulability constraint
Process.setThreadScheduler(tid, Process.SCHED_FIFO | Process.SCHED_RESET_ON_FORK,
prio);
} catch (RuntimeException e) {
Log.e(TAG, "Failed setThreadScheduler: " + e);
return PackageManager.PERMISSION_DENIED;
}
return PackageManager.PERMISSION_GRANTED;
}
// Request to move media.codec process between SP_FOREGROUND and SP_TOP_APP.
public int requestCpusetBoost(boolean enable, IBinder client) {
// Can only allow mediaserver to call this.
if (Binder.getCallingPid() != Process.myPid() &&
Binder.getCallingUid() != Process.MEDIA_UID) {
return PackageManager.PERMISSION_DENIED;
}
int[] nativePids = Process.getPidsForCommands(MEDIA_PROCESS_NAMES);
if (nativePids == null || nativePids.length != 1) {
Log.e(TAG, "requestCpusetBoost: can't find media.codec process");
return PackageManager.PERMISSION_DENIED;
}
synchronized (mDeathRecipient) {
if (enable) {
return enableCpusetBoost(nativePids[0], client);
} else {
return disableCpusetBoost(nativePids[0]);
}
}
}
private int enableCpusetBoost(int pid, IBinder client) {
if (mBoostedPid == pid) {
return PackageManager.PERMISSION_GRANTED;
}
// The mediacodec process has changed, clean up the old pid and
// client before we boost the new process, so that the state
// is left clean if things go wrong.
mBoostedPid = -1;
if (mClient != null) {
try {
mClient.unlinkToDeath(mDeathRecipient, 0);
} catch (Exception e) {
} finally {
mClient = null;
}
}
try {
client.linkToDeath(mDeathRecipient, 0);
Log.i(TAG, "Moving " + pid + " to group " + Process.THREAD_GROUP_TOP_APP);
Process.setProcessGroup(pid, Process.THREAD_GROUP_TOP_APP);
mBoostedPid = pid;
mClient = client;
return PackageManager.PERMISSION_GRANTED;
} catch (Exception e) {
Log.e(TAG, "Failed enableCpusetBoost: " + e);
try {
// unlink if things go wrong and don't crash.
client.unlinkToDeath(mDeathRecipient, 0);
} catch (Exception e1) {}
}
return PackageManager.PERMISSION_DENIED;
}
private int disableCpusetBoost(int pid) {
int boostedPid = mBoostedPid;
// Clean up states first.
mBoostedPid = -1;
if (mClient != null) {
try {
mClient.unlinkToDeath(mDeathRecipient, 0);
} catch (Exception e) {
} finally {
mClient = null;
}
}
// Try restore the old thread group, no need to fail as the
// mediacodec process could be dead just now.
if (boostedPid == pid) {
try {
Log.i(TAG, "Moving " + pid + " back to group default");
Process.setProcessGroup(pid, Process.THREAD_GROUP_DEFAULT);
} catch (Exception e) {
Log.w(TAG, "Couldn't move pid " + pid + " back to group default");
}
}
return PackageManager.PERMISSION_GRANTED;
}
private boolean isPermitted() {
// schedulerservice hidl
if (Binder.getCallingPid() == Process.myPid()) {
return true;
}
switch (Binder.getCallingUid()) {
case Process.AUDIOSERVER_UID: // fastcapture, fastmixer
case Process.CAMERASERVER_UID: // camera high frame rate recording
case Process.BLUETOOTH_UID: // Bluetooth audio playback
return true;
default:
return false;
}
}
}