TrustAgentWrapper.java revision 82142c21dd333307682d5f4bb09de3ab3ccfa06c 
1/*
2 * Copyright (C) 2014 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
17package com.android.server.trust;
18
19import android.content.ComponentName;
20import android.content.Context;
21import android.content.Intent;
22import android.content.ServiceConnection;
23import android.os.Bundle;
24import android.os.Handler;
25import android.os.IBinder;
26import android.os.Message;
27import android.os.RemoteException;
28import android.os.UserHandle;
29import android.util.Log;
30import android.util.Slog;
31import android.service.trust.ITrustAgentService;
32import android.service.trust.ITrustAgentServiceCallback;
33
34/**
35 * A wrapper around a TrustAgentService interface. Coordinates communication between
36 * TrustManager and the actual TrustAgent.
37 */
38public class TrustAgentWrapper {
39    private static final boolean DEBUG = false;
40    private static final String TAG = "TrustAgentWrapper";
41
42    private static final int MSG_ENABLE_TRUST = 1;
43    private static final int MSG_REVOKE_TRUST = 2;
44    private static final int MSG_TRUST_TIMEOUT = 3;
45
46    private final TrustManagerService mTrustManagerService;
47    private final int mUserId;
48    private final Context mContext;
49    private final ComponentName mName;
50
51    private ITrustAgentService mTrustAgentService;
52
53    // Trust state
54    private boolean mTrusted;
55    private String mMessage;
56
57    private final Handler mHandler = new Handler() {
58        @Override
59        public void handleMessage(Message msg) {
60            switch (msg.what) {
61                case MSG_ENABLE_TRUST:
62                    mTrusted = true;
63                    mMessage = (String) msg.obj;
64                    boolean initiatedByUser = msg.arg1 != 0;
65                    // TODO: Handle handle user initiated trust changes.
66                    mTrustManagerService.updateTrust(mUserId);
67                    break;
68                case MSG_TRUST_TIMEOUT:
69                    if (DEBUG) Slog.v(TAG, "Trust timed out : " + mName.flattenToShortString());
70                    // Fall through.
71                case MSG_REVOKE_TRUST:
72                    mTrusted = false;
73                    mMessage = null;
74                    mTrustManagerService.updateTrust(mUserId);
75                    break;
76            }
77        }
78    };
79
80    private ITrustAgentServiceCallback mCallback = new ITrustAgentServiceCallback.Stub() {
81
82        public void enableTrust(String userMessage, long durationMs, boolean initiatedByUser) {
83            if (DEBUG) Slog.v(TAG, "enableTrust(" + userMessage + ", durationMs = " + durationMs
84                        + ", initiatedByUser = " + initiatedByUser + ")");
85
86            mHandler.obtainMessage(MSG_ENABLE_TRUST, initiatedByUser ? 1 : 0, 0, userMessage)
87                    .sendToTarget();
88            if (durationMs > 0) {
89                mHandler.removeMessages(MSG_TRUST_TIMEOUT);
90                mHandler.sendEmptyMessageDelayed(MSG_TRUST_TIMEOUT, durationMs);
91            }
92        }
93
94        public void revokeTrust() {
95            if (DEBUG) Slog.v(TAG, "revokeTrust()");
96            mHandler.sendEmptyMessage(MSG_REVOKE_TRUST);
97        }
98    };
99
100    private final ServiceConnection mConnection = new ServiceConnection() {
101        @Override
102        public void onServiceConnected(ComponentName name, IBinder service) {
103            if (DEBUG) Log.v(TAG, "TrustAgent started : " + name.flattenToString());
104            mTrustAgentService = ITrustAgentService.Stub.asInterface(service);
105            setCallback(mCallback);
106        }
107
108        @Override
109        public void onServiceDisconnected(ComponentName name) {
110            if (DEBUG) Log.v(TAG, "TrustAgent disconnected : " + name.flattenToShortString());
111            mTrustAgentService = null;
112            mHandler.sendEmptyMessage(MSG_REVOKE_TRUST);
113        }
114    };
115
116
117    public TrustAgentWrapper(Context context, TrustManagerService trustManagerService,
118            Intent intent, UserHandle user) {
119        mContext = context;
120        mTrustManagerService = trustManagerService;
121        mUserId = user.getIdentifier();
122        mName = intent.getComponent();
123        if (!context.bindServiceAsUser(intent, mConnection, Context.BIND_AUTO_CREATE, user)) {
124            if (DEBUG) Log.v(TAG, "can't bind to TrustAgent " + mName.flattenToShortString());
125            // TODO: retry somehow?
126        }
127    }
128
129    private void onError(Exception e) {
130        Slog.w(TAG , "Remote Exception", e);
131    }
132
133    /**
134     * @see android.service.trust.TrustAgentService#onUnlockAttempt(boolean)
135     */
136    public void onUnlockAttempt(boolean successful) {
137        try {
138            if (mTrustAgentService != null) mTrustAgentService.onUnlockAttempt(successful);
139        } catch (RemoteException e) {
140            onError(e);
141        }
142    }
143
144    private void setCallback(ITrustAgentServiceCallback callback) {
145        try {
146            if (mTrustAgentService != null) {
147                mTrustAgentService.setCallback(callback);
148            }
149        } catch (RemoteException e) {
150            onError(e);
151        }
152    }
153
154    public boolean isTrusted() {
155        return mTrusted;
156    }
157
158    public String getMessage() {
159        return mMessage;
160    }
161
162    public void unbind() {
163        if (DEBUG) Log.v(TAG, "TrustAgent unbound : " + mName.flattenToShortString());
164        mContext.unbindService(mConnection);
165    }
166}
167