blob: 863490d314a3b5ca8cc44f8921a677e643abe3d4 [file] [log] [blame]
/*
* 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/poll.h>
#include <sys/types.h>
#include <unistd.h>
#include <chrono>
#include <optional>
#include <android-base/unique_fd.h>
using android::base::borrowed_fd;
using android::base::Result;
using android::base::unique_fd;
using std::chrono_literals::operator""ms;
namespace android {
namespace lshal {
Result<std::unique_ptr<PipeRelay>> PipeRelay::create(std::ostream& os,
const NullableOStream<std::ostream>& err,
const std::string& fqName) {
auto pipeRelay = std::unique_ptr<PipeRelay>(new PipeRelay());
unique_fd rfd;
if (!android::base::Pipe(&rfd, &pipeRelay->mWrite)) {
return android::base::ErrnoError() << "pipe()";
}
// Workaround for b/111997867: need a separate FD trigger because rfd can't receive POLLHUP
// when the write end is closed after the write end was sent through hwbinder.
unique_fd rfdTrigger;
if (!android::base::Pipe(&rfdTrigger, &pipeRelay->mWriteTrigger)) {
return android::base::ErrnoError() << "pipe() for trigger";
}
pipeRelay->mThread =
std::make_unique<std::thread>(&PipeRelay::thread, std::move(rfd), std::move(rfdTrigger),
&os, &err, fqName);
return pipeRelay;
}
void PipeRelay::thread(unique_fd rfd, unique_fd rfdTrigger, std::ostream* out,
const NullableOStream<std::ostream>* err, std::string fqName) {
while (true) {
pollfd pfd[2];
pfd[0] = {.fd = rfd.get(), .events = POLLIN};
pfd[1] = {.fd = rfdTrigger.get(), .events = 0};
int pollRes = poll(pfd, arraysize(pfd), -1 /* infinite timeout */);
if (pollRes < 0) {
int savedErrno = errno;
(*err) << "debug " << fqName << ": poll() failed: " << strerror(savedErrno)
<< std::endl;
break;
}
if (pfd[0].revents & POLLIN) {
char buffer[1024];
ssize_t n = TEMP_FAILURE_RETRY(read(rfd.get(), buffer, sizeof(buffer)));
if (n < 0) {
int savedErrno = errno;
(*err) << "debug " << fqName << ": read() failed: " << strerror(savedErrno)
<< std::endl;
break;
}
if (n == 0) {
(*err) << "Warning: debug " << fqName << ": poll() indicates POLLIN but no data"
<< std::endl;
continue;
}
out->write(buffer, n);
continue;
}
if (pfd[0].revents & POLLHUP) {
break;
}
if (pfd[1].revents & POLLHUP) {
// ~PipeRelay is called on the main thread. |mWrite| has been flushed and closed.
// Ensure that our read end of the pipe doesn't have pending data, then exit.
if ((pfd[0].revents & POLLIN) == 0) {
break;
}
}
}
}
PipeRelay::~PipeRelay() {
mWrite.reset();
mWriteTrigger.reset();
if (mThread != nullptr && mThread->joinable()) {
mThread->join();
}
}
} // namespace lshal
} // namespace android