Binder.cpp revision 386a332b4f70718cccb08d5511d66e9f4f5bd409 
1/*
2 * Copyright (C) 2005 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
17#include <binder/Binder.h>
18
19#include <utils/Atomic.h>
20#include <binder/BpBinder.h>
21#include <binder/IInterface.h>
22#include <binder/Parcel.h>
23
24#include <stdio.h>
25
26namespace android {
27
28// ---------------------------------------------------------------------------
29
30IBinder::IBinder()
31    : RefBase()
32{
33}
34
35IBinder::~IBinder()
36{
37}
38
39// ---------------------------------------------------------------------------
40
41sp<IInterface>  IBinder::queryLocalInterface(const String16& descriptor)
42{
43    return NULL;
44}
45
46BBinder* IBinder::localBinder()
47{
48    return NULL;
49}
50
51BpBinder* IBinder::remoteBinder()
52{
53    return NULL;
54}
55
56bool IBinder::checkSubclass(const void* /*subclassID*/) const
57{
58    return false;
59}
60
61// ---------------------------------------------------------------------------
62
63class BBinder::Extras
64{
65public:
66    Mutex mLock;
67    BpBinder::ObjectManager mObjects;
68};
69
70// ---------------------------------------------------------------------------
71
72BBinder::BBinder()
73    : mExtras(NULL)
74{
75}
76
77bool BBinder::isBinderAlive() const
78{
79    return true;
80}
81
82status_t BBinder::pingBinder()
83{
84    return NO_ERROR;
85}
86
87const String16& BBinder::getInterfaceDescriptor() const
88{
89    // This is a local static rather than a global static,
90    // to avoid static initializer ordering issues.
91    static String16 sEmptyDescriptor;
92    LOGW("reached BBinder::getInterfaceDescriptor (this=%p)", this);
93    return sEmptyDescriptor;
94}
95
96status_t BBinder::transact(
97    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
98{
99    data.setDataPosition(0);
100
101    status_t err = NO_ERROR;
102    switch (code) {
103        case PING_TRANSACTION:
104            reply->writeInt32(pingBinder());
105            break;
106        default:
107            err = onTransact(code, data, reply, flags);
108            break;
109    }
110
111    if (reply != NULL) {
112        reply->setDataPosition(0);
113    }
114
115    return err;
116}
117
118status_t BBinder::linkToDeath(
119    const sp<DeathRecipient>& recipient, void* cookie, uint32_t flags)
120{
121    return INVALID_OPERATION;
122}
123
124status_t BBinder::unlinkToDeath(
125    const wp<DeathRecipient>& recipient, void* cookie, uint32_t flags,
126    wp<DeathRecipient>* outRecipient)
127{
128    return INVALID_OPERATION;
129}
130
131status_t BBinder::dump(int fd, const Vector<String16>& args)
132{
133    return NO_ERROR;
134}
135
136void BBinder::attachObject(
137    const void* objectID, void* object, void* cleanupCookie,
138    object_cleanup_func func)
139{
140    Extras* e = mExtras;
141
142    if (!e) {
143        e = new Extras;
144        if (android_atomic_cmpxchg(0, reinterpret_cast<int32_t>(e),
145                reinterpret_cast<volatile int32_t*>(&mExtras)) != 0) {
146            delete e;
147            e = mExtras;
148        }
149        if (e == 0) return; // out of memory
150    }
151
152    AutoMutex _l(e->mLock);
153    e->mObjects.attach(objectID, object, cleanupCookie, func);
154}
155
156void* BBinder::findObject(const void* objectID) const
157{
158    Extras* e = mExtras;
159    if (!e) return NULL;
160
161    AutoMutex _l(e->mLock);
162    return e->mObjects.find(objectID);
163}
164
165void BBinder::detachObject(const void* objectID)
166{
167    Extras* e = mExtras;
168    if (!e) return;
169
170    AutoMutex _l(e->mLock);
171    e->mObjects.detach(objectID);
172}
173
174BBinder* BBinder::localBinder()
175{
176    return this;
177}
178
179BBinder::~BBinder()
180{
181    if (mExtras) delete mExtras;
182}
183
184
185status_t BBinder::onTransact(
186    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
187{
188    switch (code) {
189        case INTERFACE_TRANSACTION:
190            reply->writeString16(getInterfaceDescriptor());
191            return NO_ERROR;
192
193        case DUMP_TRANSACTION: {
194            int fd = data.readFileDescriptor();
195            int argc = data.readInt32();
196            Vector<String16> args;
197            for (int i = 0; i < argc && data.dataAvail() > 0; i++) {
198               args.add(data.readString16());
199            }
200            return dump(fd, args);
201        }
202        default:
203            return UNKNOWN_TRANSACTION;
204    }
205}
206
207// ---------------------------------------------------------------------------
208
209enum {
210    // This is used to transfer ownership of the remote binder from
211    // the BpRefBase object holding it (when it is constructed), to the
212    // owner of the BpRefBase object when it first acquires that BpRefBase.
213    kRemoteAcquired = 0x00000001
214};
215
216BpRefBase::BpRefBase(const sp<IBinder>& o)
217    : mRemote(o.get()), mRefs(NULL), mState(0)
218{
219    extendObjectLifetime(OBJECT_LIFETIME_WEAK);
220
221    if (mRemote) {
222        mRemote->incStrong(this);           // Removed on first IncStrong().
223        mRefs = mRemote->createWeak(this);  // Held for our entire lifetime.
224    }
225}
226
227BpRefBase::~BpRefBase()
228{
229    if (mRemote) {
230        if (!(mState&kRemoteAcquired)) {
231            mRemote->decStrong(this);
232        }
233        mRefs->decWeak(this);
234    }
235}
236
237void BpRefBase::onFirstRef()
238{
239    android_atomic_or(kRemoteAcquired, &mState);
240}
241
242void BpRefBase::onLastStrongRef(const void* id)
243{
244    if (mRemote) {
245        mRemote->decStrong(this);
246    }
247}
248
249bool BpRefBase::onIncStrongAttempted(uint32_t flags, const void* id)
250{
251    return mRemote ? mRefs->attemptIncStrong(this) : false;
252}
253
254// ---------------------------------------------------------------------------
255
256}; // namespace android
257