1693f420d4
Prepare for introducing a second interprocess communication channel by introducing the class InterprocessFifo. Stop using std::unique_ptr<> for holding the pipe file descriptors. Handle EOF consistently. Bug: 213617178 Change-Id: Ic0cf18d3d8ea61b8ee17e64de8a9df2736e26728 Signed-off-by: Bart Van Assche <bvanassche@google.com>
96 lines
2.3 KiB
C++
96 lines
2.3 KiB
C++
/*
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* Copyright (C) 2022 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "interprocess_fifo.h"
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#include <android-base/logging.h>
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#include <unistd.h>
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using ::android::base::ErrnoError;
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using ::android::base::Error;
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using ::android::base::Result;
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namespace android {
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namespace init {
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InterprocessFifo::InterprocessFifo() noexcept : fds_({-1, -1}) {}
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InterprocessFifo::InterprocessFifo(InterprocessFifo&& orig) noexcept : fds_({-1, -1}) {
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std::swap(fds_, orig.fds_);
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}
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InterprocessFifo::~InterprocessFifo() noexcept {
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Close();
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}
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void InterprocessFifo::CloseFd(int& fd) noexcept {
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if (fd >= 0) {
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close(fd);
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fd = -1;
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}
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}
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void InterprocessFifo::CloseReadFd() noexcept {
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CloseFd(fds_[0]);
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}
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void InterprocessFifo::CloseWriteFd() noexcept {
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CloseFd(fds_[1]);
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}
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void InterprocessFifo::Close() noexcept {
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CloseReadFd();
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CloseWriteFd();
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}
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Result<void> InterprocessFifo::Initialize() noexcept {
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if (fds_[0] >= 0) {
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return Error() << "already initialized";
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}
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if (pipe(fds_.data()) < 0) { // NOLINT(android-cloexec-pipe)
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return ErrnoError() << "pipe()";
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}
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return {};
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}
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Result<uint8_t> InterprocessFifo::Read() noexcept {
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uint8_t byte;
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ssize_t count = read(fds_[0], &byte, 1);
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if (count < 0) {
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return ErrnoError() << "read()";
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}
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if (count == 0) {
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return Error() << "read() EOF";
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}
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DCHECK_EQ(count, 1);
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return byte;
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}
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Result<void> InterprocessFifo::Write(uint8_t byte) noexcept {
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ssize_t written = write(fds_[1], &byte, 1);
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if (written < 0) {
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return ErrnoError() << "write()";
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}
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if (written == 0) {
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return Error() << "write() EOF";
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}
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DCHECK_EQ(written, 1);
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return {};
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}
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} // namespace init
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} // namespace android
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