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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 <utils/Thread.h>
namespace android {
namespace lshal {
static constexpr struct timeval READ_TIMEOUT { .tv_sec = 1, .tv_usec = 0 };
static std::string getThreadName(std::string interfaceName, const std::string &instanceName) {
auto dot = interfaceName.rfind(".");
if (dot != std::string::npos) interfaceName = interfaceName.substr(dot + 1);
return "RelayThread_" + interfaceName + "_" + instanceName;
}
struct PipeRelay::RelayThread : public Thread {
explicit RelayThread(int fd, std::ostream &os, const NullableOStream<std::ostream> &err,
const std::string &fqName);
bool threadLoop() override;
void setFinished();
private:
int mFd;
std::ostream &mOutStream;
NullableOStream<std::ostream> mErrStream;
// 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;
std::string mFqName;
DISALLOW_COPY_AND_ASSIGN(RelayThread);
};
////////////////////////////////////////////////////////////////////////////////
PipeRelay::RelayThread::RelayThread(int fd, std::ostream &os,
const NullableOStream<std::ostream> &err,
const std::string &fqName)
: mFd(fd), mOutStream(os), mErrStream(err), mFinished(false), mFqName(fqName) {}
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) {
mErrStream << "debug " << mFqName << ": select() failed";
return false;
}
if (res == 0 || !FD_ISSET(mFd, &set)) {
if (mFinished) {
mErrStream << "debug " << mFqName
<< ": 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) {
mErrStream << "debug " << mFqName << ": read() failed";
}
if (n <= 0) {
return false;
}
mOutStream.write(buffer, n);
return true;
}
void PipeRelay::RelayThread::setFinished() {
mFinished = true;
}
////////////////////////////////////////////////////////////////////////////////
PipeRelay::PipeRelay(std::ostream &os, const NullableOStream<std::ostream> &err,
const std::string &interfaceName, const std::string &instanceName)
: mInitCheck(NO_INIT) {
int res = pipe(mFds);
if (res < 0) {
mInitCheck = -errno;
return;
}
mThread = new RelayThread(mFds[0], os, err, interfaceName + "/" + instanceName);
mInitCheck = mThread->run(getThreadName(interfaceName, instanceName).c_str());
}
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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