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- /*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- #include "PipeRelay.h"
- #include <sys/select.h>
- #include <sys/time.h>
- #include <sys/types.h>
- #include <unistd.h>
- #include <atomic>
- #include <android-base/logging.h>
- #include <utils/Thread.h>
- namespace android {
- namespace lshal {
- static constexpr struct timeval READ_TIMEOUT { .tv_sec = 1, .tv_usec = 0 };
- struct PipeRelay::RelayThread : public Thread {
- explicit RelayThread(int fd, std::ostream &os);
- bool threadLoop() override;
- void setFinished();
- private:
- int mFd;
- std::ostream &mOutStream;
- // If we were to use requestExit() and exitPending() instead, threadLoop()
- // may not run at all by the time ~PipeRelay is called (i.e. debug() has
- // returned from HAL). By using our own flag, we ensure that select() and
- // read() are executed until data are drained.
- std::atomic_bool mFinished;
- DISALLOW_COPY_AND_ASSIGN(RelayThread);
- };
- ////////////////////////////////////////////////////////////////////////////////
- PipeRelay::RelayThread::RelayThread(int fd, std::ostream &os)
- : mFd(fd), mOutStream(os), mFinished(false) {}
- bool PipeRelay::RelayThread::threadLoop() {
- char buffer[1024];
- fd_set set;
- FD_ZERO(&set);
- FD_SET(mFd, &set);
- struct timeval timeout = READ_TIMEOUT;
- int res = TEMP_FAILURE_RETRY(select(mFd + 1, &set, nullptr, nullptr, &timeout));
- if (res < 0) {
- PLOG(INFO) << "select() failed";
- return false;
- }
- if (res == 0 || !FD_ISSET(mFd, &set)) {
- if (mFinished) {
- LOG(WARNING) << "debug: timeout reading from pipe, output may be truncated.";
- return false;
- }
- // timeout, but debug() has not returned, so wait for HAL to finish.
- return true;
- }
- // FD_ISSET(mFd, &set) == true. Data available, start reading
- ssize_t n = TEMP_FAILURE_RETRY(read(mFd, buffer, sizeof(buffer)));
- if (n < 0) {
- PLOG(ERROR) << "read() failed";
- }
- if (n <= 0) {
- return false;
- }
- mOutStream.write(buffer, n);
- return true;
- }
- void PipeRelay::RelayThread::setFinished() {
- mFinished = true;
- }
- ////////////////////////////////////////////////////////////////////////////////
- PipeRelay::PipeRelay(std::ostream &os)
- : mInitCheck(NO_INIT) {
- int res = pipe(mFds);
- if (res < 0) {
- mInitCheck = -errno;
- return;
- }
- mThread = new RelayThread(mFds[0], os);
- mInitCheck = mThread->run("RelayThread");
- }
- void PipeRelay::CloseFd(int *fd) {
- if (*fd >= 0) {
- close(*fd);
- *fd = -1;
- }
- }
- PipeRelay::~PipeRelay() {
- CloseFd(&mFds[1]);
- if (mThread != nullptr) {
- mThread->setFinished();
- mThread->join();
- mThread.clear();
- }
- CloseFd(&mFds[0]);
- }
- status_t PipeRelay::initCheck() const {
- return mInitCheck;
- }
- int PipeRelay::fd() const {
- return mFds[1];
- }
- } // namespace lshal
- } // namespace android
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