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 <stdatomic.h>
20#include <utils/misc.h>
21#include <binder/BpBinder.h>
22#include <binder/IInterface.h>
23#include <binder/Parcel.h>
24
25#include <stdio.h>
26
27namespace android {
28
29// ---------------------------------------------------------------------------
30
31IBinder::IBinder()
32    : RefBase()
33{
34}
35
36IBinder::~IBinder()
37{
38}
39
40// ---------------------------------------------------------------------------
41
42sp<IInterface>  IBinder::queryLocalInterface(const String16& /*descriptor*/)
43{
44    return NULL;
45}
46
47BBinder* IBinder::localBinder()
48{
49    return NULL;
50}
51
52BpBinder* IBinder::remoteBinder()
53{
54    return NULL;
55}
56
57bool IBinder::checkSubclass(const void* /*subclassID*/) const
58{
59    return false;
60}
61
62// ---------------------------------------------------------------------------
63
64class BBinder::Extras
65{
66public:
67    Mutex mLock;
68    BpBinder::ObjectManager mObjects;
69};
70
71// ---------------------------------------------------------------------------
72
73BBinder::BBinder()
74{
75    atomic_init(&mExtras, 0);
76}
77
78bool BBinder::isBinderAlive() const
79{
80    return true;
81}
82
83status_t BBinder::pingBinder()
84{
85    return NO_ERROR;
86}
87
88const String16& BBinder::getInterfaceDescriptor() const
89{
90    // This is a local static rather than a global static,
91    // to avoid static initializer ordering issues.
92    static String16 sEmptyDescriptor;
93    ALOGW("reached BBinder::getInterfaceDescriptor (this=%p)", this);
94    return sEmptyDescriptor;
95}
96
97status_t BBinder::transact(
98    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
99{
100    data.setDataPosition(0);
101
102    status_t err = NO_ERROR;
103    switch (code) {
104        case PING_TRANSACTION:
105            reply->writeInt32(pingBinder());
106            break;
107        default:
108            err = onTransact(code, data, reply, flags);
109            break;
110    }
111
112    if (reply != NULL) {
113        reply->setDataPosition(0);
114    }
115
116    return err;
117}
118
119status_t BBinder::linkToDeath(
120    const sp<DeathRecipient>& /*recipient*/, void* /*cookie*/,
121    uint32_t /*flags*/)
122{
123    return INVALID_OPERATION;
124}
125
126status_t BBinder::unlinkToDeath(
127    const wp<DeathRecipient>& /*recipient*/, void* /*cookie*/,
128    uint32_t /*flags*/, wp<DeathRecipient>* /*outRecipient*/)
129{
130    return INVALID_OPERATION;
131}
132
133    status_t BBinder::dump(int /*fd*/, const Vector<String16>& /*args*/)
134{
135    return NO_ERROR;
136}
137
138void BBinder::attachObject(
139    const void* objectID, void* object, void* cleanupCookie,
140    object_cleanup_func func)
141{
142    Extras* e = reinterpret_cast<Extras*>(
143                    atomic_load_explicit(&mExtras, memory_order_acquire));
144
145    if (!e) {
146        e = new Extras;
147        uintptr_t expected = 0;
148        if (!atomic_compare_exchange_strong_explicit(
149                                        &mExtras, &expected,
150                                        reinterpret_cast<uintptr_t>(e),
151                                        memory_order_release,
152                                        memory_order_acquire)) {
153            delete e;
154            e = reinterpret_cast<Extras*>(expected);  // Filled in by CAS
155        }
156        if (e == 0) return; // out of memory
157    }
158
159    AutoMutex _l(e->mLock);
160    e->mObjects.attach(objectID, object, cleanupCookie, func);
161}
162
163void* BBinder::findObject(const void* objectID) const
164{
165    Extras* e = reinterpret_cast<Extras*>(
166                    atomic_load_explicit(&mExtras, memory_order_acquire));
167    if (!e) return NULL;
168
169    AutoMutex _l(e->mLock);
170    return e->mObjects.find(objectID);
171}
172
173void BBinder::detachObject(const void* objectID)
174{
175    Extras* e = reinterpret_cast<Extras*>(
176                    atomic_load_explicit(&mExtras, memory_order_acquire));
177    if (!e) return;
178
179    AutoMutex _l(e->mLock);
180    e->mObjects.detach(objectID);
181}
182
183BBinder* BBinder::localBinder()
184{
185    return this;
186}
187
188BBinder::~BBinder()
189{
190    Extras* e = reinterpret_cast<Extras*>(
191                    atomic_load_explicit(&mExtras, memory_order_relaxed));
192    if (e) delete e;
193}
194
195
196status_t BBinder::onTransact(
197    uint32_t code, const Parcel& data, Parcel* reply, uint32_t /*flags*/)
198{
199    switch (code) {
200        case INTERFACE_TRANSACTION:
201            reply->writeString16(getInterfaceDescriptor());
202            return NO_ERROR;
203
204        case DUMP_TRANSACTION: {
205            int fd = data.readFileDescriptor();
206            int argc = data.readInt32();
207            Vector<String16> args;
208            for (int i = 0; i < argc && data.dataAvail() > 0; i++) {
209               args.add(data.readString16());
210            }
211            return dump(fd, args);
212        }
213
214        case SYSPROPS_TRANSACTION: {
215            report_sysprop_change();
216            return NO_ERROR;
217        }
218
219        default:
220            return UNKNOWN_TRANSACTION;
221    }
222}
223
224// ---------------------------------------------------------------------------
225
226enum {
227    // This is used to transfer ownership of the remote binder from
228    // the BpRefBase object holding it (when it is constructed), to the
229    // owner of the BpRefBase object when it first acquires that BpRefBase.
230    kRemoteAcquired = 0x00000001
231};
232
233BpRefBase::BpRefBase(const sp<IBinder>& o)
234    : mRemote(o.get()), mRefs(NULL), mState(0)
235{
236    extendObjectLifetime(OBJECT_LIFETIME_WEAK);
237
238    if (mRemote) {
239        mRemote->incStrong(this);           // Removed on first IncStrong().
240        mRefs = mRemote->createWeak(this);  // Held for our entire lifetime.
241    }
242}
243
244BpRefBase::~BpRefBase()
245{
246    if (mRemote) {
247        if (!(mState&kRemoteAcquired)) {
248            mRemote->decStrong(this);
249        }
250        mRefs->decWeak(this);
251    }
252}
253
254void BpRefBase::onFirstRef()
255{
256    android_atomic_or(kRemoteAcquired, &mState);
257}
258
259void BpRefBase::onLastStrongRef(const void* /*id*/)
260{
261    if (mRemote) {
262        mRemote->decStrong(this);
263    }
264}
265
266bool BpRefBase::onIncStrongAttempted(uint32_t /*flags*/, const void* /*id*/)
267{
268    return mRemote ? mRefs->attemptIncStrong(this) : false;
269}
270
271// ---------------------------------------------------------------------------
272
273}; // namespace android
274