Avichal Rakesh | fcb78cb | 2022-10-27 15:45:54 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2022 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 | #define LOG_TAG "DeathPipe" |
| 18 | |
| 19 | #include "DeathPipe.h" |
| 20 | |
| 21 | namespace android::frameworks::cameraservice::utils { |
| 22 | |
| 23 | DeathPipe::DeathPipe(IBinder* parent, const ::ndk::SpAIBinder& binder): |
| 24 | mParent(parent), mAIBinder(binder) { |
| 25 | mDeathRecipient = ::ndk::ScopedAIBinder_DeathRecipient( |
| 26 | AIBinder_DeathRecipient_new(DeathPipe::onDeathCallback)); |
| 27 | // Set an unlinked callback that allows Obituaries to be deallocated |
| 28 | AIBinder_DeathRecipient_setOnUnlinked(mDeathRecipient.get(), |
| 29 | DeathPipe::onUnlinkedCallback); |
| 30 | } |
| 31 | |
| 32 | status_t DeathPipe::linkToDeath(const sp<IBinder::DeathRecipient>& recipient, |
| 33 | void* cookie, uint32_t flags) { |
| 34 | LOG_ALWAYS_FATAL_IF(recipient == nullptr, "%s: recipient must be non-nullptr", __FUNCTION__); |
| 35 | std::lock_guard<std::mutex> _l(mLock); |
| 36 | |
| 37 | // Create and immortalize an obituary before linking it to death. |
| 38 | // The created Obituary can now only be garbage collected if it is unlinked from death |
| 39 | std::shared_ptr<Obituary> obituary = std::make_shared<Obituary>(recipient, cookie, |
| 40 | flags, /* who= */ mParent); |
| 41 | obituary->immortalize(); |
| 42 | |
| 43 | // Ensure that "cookie" is a pointer to an immortal obituary. |
| 44 | // AIBinder_linkToDeath calls DeathPipe::onUnlinkedCallback if linking to death fails, marking |
| 45 | // it for garbage collection |
| 46 | binder_status_t ret = AIBinder_linkToDeath(mAIBinder.get(), |
| 47 | mDeathRecipient.get(), |
| 48 | /* cookie= */ obituary.get()); |
| 49 | if (ret != STATUS_OK) { |
| 50 | return DEAD_OBJECT; |
| 51 | } |
| 52 | mObituaries.emplace_back(obituary); |
| 53 | return NO_ERROR; |
| 54 | } |
| 55 | |
| 56 | status_t DeathPipe::unlinkToDeath(const wp<IBinder::DeathRecipient>& recipient, |
| 57 | void* cookie, uint32_t flags, |
| 58 | wp<IBinder::DeathRecipient>* outRecipient) { |
| 59 | std::lock_guard<std::mutex> _l(mLock); |
| 60 | // Temporary Obituary for checking equality |
| 61 | std::shared_ptr<Obituary> inObituary = std::make_shared<Obituary>(recipient, cookie, |
| 62 | flags, mParent); |
| 63 | for (auto it = mObituaries.begin(); it != mObituaries.end(); it++) { |
| 64 | if ((*inObituary) == (**it)) { |
| 65 | if (outRecipient != nullptr) { |
| 66 | *outRecipient = (*it)->recipient; |
| 67 | } |
| 68 | // Unlink the found Obituary from death. AIBinder_unlinkToDeath calls |
| 69 | // DeathPipe::onUnlinkedCallback with the given cookie when unlinking is done |
| 70 | binder_status_t ret = AIBinder_unlinkToDeath(mAIBinder.get(), |
| 71 | mDeathRecipient.get(), |
| 72 | /* cookie= */ (*it).get()); |
| 73 | mObituaries.erase(it); |
| 74 | return ret == STATUS_OK ? NO_ERROR : DEAD_OBJECT; |
| 75 | } |
| 76 | } |
| 77 | return NAME_NOT_FOUND; |
| 78 | } |
| 79 | |
| 80 | DeathPipe::~DeathPipe() = default; |
| 81 | |
| 82 | |
| 83 | void DeathPipe::onDeathCallback(void* cookie) { |
| 84 | // Cookie will always be a pointer to a valid immortal Obituary |
| 85 | Obituary* obituary = static_cast<Obituary*>(cookie); |
| 86 | obituary->onDeath(); |
| 87 | // Don't call Obituary::clear() because VNDK Binder will call DeathPipe::onUnlinkedCallback() |
| 88 | // when it is ready |
| 89 | } |
| 90 | |
| 91 | void DeathPipe::onUnlinkedCallback(void* cookie) { |
| 92 | // Cookie will always be a pointer to a valid immortal Obituary. |
| 93 | Obituary* obituary = static_cast<Obituary*>(cookie); |
| 94 | // Mark obituary to be garbage collected if needed. onDeathCallback won't be called with |
| 95 | // this particular cookie after this. |
| 96 | obituary->clear(); |
| 97 | } |
| 98 | |
| 99 | } // namespace android::frameworks::cameraservice::utils |