7a96c39c51
This helps reduce the pressure on framework.jar, and makes it clear that it should only be used by the system_server. Bug: 7333397 Change-Id: I0858904239535380fbf30562b793e277d8c3f054
65 lines
2.5 KiB
Java
65 lines
2.5 KiB
Java
/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.server.os;
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import android.content.pm.PackageManager;
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import android.os.Binder;
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import android.os.ISchedulingPolicyService;
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import android.os.Process;
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/**
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* The implementation of the scheduling policy service interface.
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*
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* @hide
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*/
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public class SchedulingPolicyService extends ISchedulingPolicyService.Stub {
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private static final String TAG = "SchedulingPolicyService";
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// Minimum and maximum values allowed for requestPriority parameter prio
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private static final int PRIORITY_MIN = 1;
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private static final int PRIORITY_MAX = 3;
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public SchedulingPolicyService() {
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}
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public int requestPriority(int pid, int tid, int prio) {
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//Log.i(TAG, "requestPriority(pid=" + pid + ", tid=" + tid + ", prio=" + prio + ")");
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// Verify that caller is mediaserver, priority is in range, and that the
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// callback thread specified by app belongs to the app that called mediaserver.
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// Once we've verified that the caller is mediaserver, we can trust the pid but
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// we can't trust the tid. No need to explicitly check for pid == 0 || tid == 0,
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// since if not the case then the getThreadGroupLeader() test will also fail.
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if (Binder.getCallingUid() != Process.MEDIA_UID || prio < PRIORITY_MIN ||
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prio > PRIORITY_MAX || Process.getThreadGroupLeader(tid) != pid) {
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return PackageManager.PERMISSION_DENIED;
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}
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try {
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// make good use of our CAP_SYS_NICE capability
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Process.setThreadGroup(tid, Binder.getCallingPid() == pid ?
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Process.THREAD_GROUP_AUDIO_SYS : Process.THREAD_GROUP_AUDIO_APP);
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// must be in this order or it fails the schedulability constraint
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Process.setThreadScheduler(tid, Process.SCHED_FIFO, prio);
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} catch (RuntimeException e) {
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return PackageManager.PERMISSION_DENIED;
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}
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return PackageManager.PERMISSION_GRANTED;
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}
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}
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