TrustAgentWrapper.java revision 7a4f3d448b17b4bea190c906d7ecc7f8bec9ff80 
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.Handler;
24import android.os.IBinder;
25import android.os.Message;
26import android.os.RemoteException;
27import android.os.UserHandle;
28import android.util.Log;
29import android.util.Slog;
30import android.service.trust.ITrustAgentService;
31import android.service.trust.ITrustAgentServiceCallback;
32
33/**
34 * A wrapper around a TrustAgentService interface. Coordinates communication between
35 * TrustManager and the actual TrustAgent.
36 */
37public class TrustAgentWrapper {
38    private static final boolean DEBUG = false;
39    private static final String TAG = "TrustAgentWrapper";
40
41    private static final int MSG_GRANT_TRUST = 1;
42    private static final int MSG_REVOKE_TRUST = 2;
43    private static final int MSG_TRUST_TIMEOUT = 3;
44
45    /**
46     * Long extra for {@link #MSG_GRANT_TRUST}
47     */
48    private static final String DATA_DURATION = "duration";
49
50    private final TrustManagerService mTrustManagerService;
51    private final int mUserId;
52    private final Context mContext;
53    private final ComponentName mName;
54
55    private ITrustAgentService mTrustAgentService;
56
57    // Trust state
58    private boolean mTrusted;
59    private CharSequence mMessage;
60
61    private final Handler mHandler = new Handler() {
62        @Override
63        public void handleMessage(Message msg) {
64            switch (msg.what) {
65                case MSG_GRANT_TRUST:
66                    mTrusted = true;
67                    mMessage = (CharSequence) msg.obj;
68                    boolean initiatedByUser = msg.arg1 != 0;
69                    // TODO: Handle initiatedByUser.
70                    long durationMs = msg.getData().getLong(DATA_DURATION);
71                    if (durationMs > 0) {
72                        mHandler.removeMessages(MSG_TRUST_TIMEOUT);
73                        mHandler.sendEmptyMessageDelayed(MSG_TRUST_TIMEOUT, durationMs);
74                    }
75                    mTrustManagerService.mArchive.logGrantTrust(mUserId, mName,
76                            (mMessage != null ? mMessage.toString() : null),
77                            durationMs, initiatedByUser);
78                    mTrustManagerService.updateTrust(mUserId);
79                    break;
80                case MSG_TRUST_TIMEOUT:
81                    if (DEBUG) Slog.v(TAG, "Trust timed out : " + mName.flattenToShortString());
82                    mTrustManagerService.mArchive.logTrustTimeout(mUserId, mName);
83                    // Fall through.
84                case MSG_REVOKE_TRUST:
85                    mTrusted = false;
86                    mMessage = null;
87                    mHandler.removeMessages(MSG_TRUST_TIMEOUT);
88                    if (msg.what == MSG_REVOKE_TRUST) {
89                        mTrustManagerService.mArchive.logRevokeTrust(mUserId, mName);
90                    }
91                    mTrustManagerService.updateTrust(mUserId);
92                    break;
93            }
94        }
95    };
96
97    private ITrustAgentServiceCallback mCallback = new ITrustAgentServiceCallback.Stub() {
98
99        @Override
100        public void grantTrust(CharSequence userMessage, long durationMs, boolean initiatedByUser) {
101            if (DEBUG) Slog.v(TAG, "enableTrust(" + userMessage + ", durationMs = " + durationMs
102                        + ", initiatedByUser = " + initiatedByUser + ")");
103
104            Message msg = mHandler.obtainMessage(
105                    MSG_GRANT_TRUST, initiatedByUser ? 1 : 0, 0, userMessage);
106            msg.getData().putLong(DATA_DURATION, durationMs);
107            msg.sendToTarget();
108        }
109
110        @Override
111        public void revokeTrust() {
112            if (DEBUG) Slog.v(TAG, "revokeTrust()");
113            mHandler.sendEmptyMessage(MSG_REVOKE_TRUST);
114        }
115    };
116
117    private final ServiceConnection mConnection = new ServiceConnection() {
118        @Override
119        public void onServiceConnected(ComponentName name, IBinder service) {
120            if (DEBUG) Log.v(TAG, "TrustAgent started : " + name.flattenToString());
121            mTrustAgentService = ITrustAgentService.Stub.asInterface(service);
122            setCallback(mCallback);
123        }
124
125        @Override
126        public void onServiceDisconnected(ComponentName name) {
127            if (DEBUG) Log.v(TAG, "TrustAgent disconnected : " + name.flattenToShortString());
128            mTrustAgentService = null;
129            mTrustManagerService.mArchive.logAgentDied(mUserId, name);
130            mHandler.sendEmptyMessage(MSG_REVOKE_TRUST);
131        }
132    };
133
134
135    public TrustAgentWrapper(Context context, TrustManagerService trustManagerService,
136            Intent intent, UserHandle user) {
137        mContext = context;
138        mTrustManagerService = trustManagerService;
139        mUserId = user.getIdentifier();
140        mName = intent.getComponent();
141        if (!context.bindServiceAsUser(intent, mConnection, Context.BIND_AUTO_CREATE, user)) {
142            if (DEBUG) Log.v(TAG, "can't bind to TrustAgent " + mName.flattenToShortString());
143            // TODO: retry somehow?
144        }
145    }
146
147    private void onError(Exception e) {
148        Slog.w(TAG , "Remote Exception", e);
149    }
150
151    /**
152     * @see android.service.trust.TrustAgentService#onUnlockAttempt(boolean)
153     */
154    public void onUnlockAttempt(boolean successful) {
155        try {
156            if (mTrustAgentService != null) mTrustAgentService.onUnlockAttempt(successful);
157        } catch (RemoteException e) {
158            onError(e);
159        }
160    }
161
162    private void setCallback(ITrustAgentServiceCallback callback) {
163        try {
164            if (mTrustAgentService != null) {
165                mTrustAgentService.setCallback(callback);
166            }
167        } catch (RemoteException e) {
168            onError(e);
169        }
170    }
171
172    public boolean isTrusted() {
173        return mTrusted;
174    }
175
176    public CharSequence getMessage() {
177        return mMessage;
178    }
179
180    public void unbind() {
181        if (DEBUG) Log.v(TAG, "TrustAgent unbound : " + mName.flattenToShortString());
182        mContext.unbindService(mConnection);
183    }
184
185    public boolean isConnected() {
186        return mTrustAgentService != null;
187    }
188}
189