Bart Van Assche | 1693f42 | 2022-10-19 16:30:15 -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 | #include "interprocess_fifo.h" |
| 18 | |
| 19 | #include <android-base/logging.h> |
| 20 | |
| 21 | #include <unistd.h> |
| 22 | |
| 23 | using ::android::base::ErrnoError; |
| 24 | using ::android::base::Error; |
| 25 | using ::android::base::Result; |
| 26 | |
| 27 | namespace android { |
| 28 | namespace init { |
| 29 | |
| 30 | InterprocessFifo::InterprocessFifo() noexcept : fds_({-1, -1}) {} |
| 31 | |
| 32 | InterprocessFifo::InterprocessFifo(InterprocessFifo&& orig) noexcept : fds_({-1, -1}) { |
| 33 | std::swap(fds_, orig.fds_); |
| 34 | } |
| 35 | |
| 36 | InterprocessFifo::~InterprocessFifo() noexcept { |
| 37 | Close(); |
| 38 | } |
| 39 | |
| 40 | void InterprocessFifo::CloseFd(int& fd) noexcept { |
| 41 | if (fd >= 0) { |
| 42 | close(fd); |
| 43 | fd = -1; |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | void InterprocessFifo::CloseReadFd() noexcept { |
| 48 | CloseFd(fds_[0]); |
| 49 | } |
| 50 | |
| 51 | void InterprocessFifo::CloseWriteFd() noexcept { |
| 52 | CloseFd(fds_[1]); |
| 53 | } |
| 54 | |
| 55 | void InterprocessFifo::Close() noexcept { |
| 56 | CloseReadFd(); |
| 57 | CloseWriteFd(); |
| 58 | } |
| 59 | |
| 60 | Result<void> InterprocessFifo::Initialize() noexcept { |
| 61 | if (fds_[0] >= 0) { |
| 62 | return Error() << "already initialized"; |
| 63 | } |
| 64 | if (pipe(fds_.data()) < 0) { // NOLINT(android-cloexec-pipe) |
| 65 | return ErrnoError() << "pipe()"; |
| 66 | } |
| 67 | return {}; |
| 68 | } |
| 69 | |
| 70 | Result<uint8_t> InterprocessFifo::Read() noexcept { |
| 71 | uint8_t byte; |
| 72 | ssize_t count = read(fds_[0], &byte, 1); |
| 73 | if (count < 0) { |
| 74 | return ErrnoError() << "read()"; |
| 75 | } |
| 76 | if (count == 0) { |
| 77 | return Error() << "read() EOF"; |
| 78 | } |
| 79 | DCHECK_EQ(count, 1); |
| 80 | return byte; |
| 81 | } |
| 82 | |
| 83 | Result<void> InterprocessFifo::Write(uint8_t byte) noexcept { |
| 84 | ssize_t written = write(fds_[1], &byte, 1); |
| 85 | if (written < 0) { |
| 86 | return ErrnoError() << "write()"; |
| 87 | } |
| 88 | if (written == 0) { |
| 89 | return Error() << "write() EOF"; |
| 90 | } |
| 91 | DCHECK_EQ(written, 1); |
| 92 | return {}; |
| 93 | } |
| 94 | |
| 95 | } // namespace init |
| 96 | } // namespace android |