#include "Watchdog.h"
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <cstdlib>
#include <cstring>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <thread>
#include "definitions.h"
WatchdogTask::WatchdogTask() : fd(0) {
int result = 0;
std::error_code e;
// Only create the FIFO if it does not exist yet
if (not std::filesystem::exists(watchdog::FIFO_NAME, e)) {
// Permission 666 or rw-rw-rw-
mode_t mode = DEFFILEMODE;
result = mkfifo(watchdog::FIFO_NAME.c_str(), mode);
if (result != 0) {
std::cerr << "Could not created named pipe at " << watchdog::FIFO_NAME << ", error " << errno
<< ": " << strerror(errno) << std::endl;
throw std::runtime_error("eive-watchdog: FIFO creation failed");
}
#if WATCHDOG_VERBOSE_LEVEL >= 1
std::cout << "Pipe at " << watchdog::FIFO_NAME << " created successfully" << std::endl;
#endif
}
}
WatchdogTask::~WatchdogTask() {}
int WatchdogTask::performOperation() {
// Open FIFO read only and non-blocking
fd = open(watchdog::FIFO_NAME.c_str(), O_RDONLY | O_NONBLOCK);
if (fd < 0) {
std::cerr << "Opening pipe " << watchdog::FIFO_NAME << "read-only failed with " << errno << ": "
<< strerror(errno) << std::endl;
return -1;
}
// Clear FIFO by reading until it is empty.
while (true) {
ssize_t readBytes = read(fd, buf.data(), buf.size());
if (readBytes < 0) {
std::cerr << "Read error of FIFO: " << strerror(errno) << std::endl;
} else if (readBytes == 0) {
break;
}
}
state = States::NOT_STARTED;
bool breakOuter = false;
while (true) {
watchdogLoop();
while (not resultQueue.empty()) {
auto nextRequest = resultQueue.front();
if (not stateMachine(nextRequest)) {
breakOuter = true;
resultQueue.pop();
break;
}
resultQueue.pop();
}
if (breakOuter) {
break;
}
}
if (close(fd) < 0) {
std::cerr << "Closing named pipe at " << watchdog::FIFO_NAME << "failed, error " << errno
<< ": " << strerror(errno) << std::endl;
}
std::cout << "Closing" << std::endl;
return 0;
}
void WatchdogTask::watchdogLoop() {
using namespace std::chrono_literals;
struct pollfd waiter = {};
waiter.fd = fd;
waiter.events = POLLIN;
// Only poll one file descriptor with timeout
switch (poll(&waiter, 1, watchdog::TIMEOUT_MS)) {
case (0): {
resultQueue.push(LoopResult::TIMEOUT);
return;
}
case (1): {
pollEvent(waiter);
return;
}
default: {
std::cerr << "Unknown poll error at " << watchdog::FIFO_NAME << ", error " << errno << ": "
<< strerror(errno) << std::endl;
break;
}
}
}
void WatchdogTask::pollEvent(struct pollfd& waiter) {
if (waiter.revents & POLLIN) {
ssize_t readLen = read(fd, buf.data(), buf.size());
#if WATCHDOG_VERBOSE_LEVEL == 2
std::cout << "Read " << readLen << " byte(s) on the pipe " << watchdog::FIFO_NAME << std::endl;
#endif
if (readLen < 0) {
std::cerr << "Read error on pipe " << watchdog::FIFO_NAME << ", error " << errno << ": "
<< strerror(errno) << std::endl;
resultQueue.push(LoopResult::OK);
} else if (readLen >= 1) {
parseCommands(readLen);
}
} else if (waiter.revents & POLLERR) {
std::cerr << "Poll error error on pipe " << watchdog::FIFO_NAME << std::endl;
resultQueue.push(LoopResult::FAULT);
} else if (waiter.revents & POLLHUP) {
// Writer closed its end
resultQueue.push(LoopResult::HUNG_UP);
}
}
void WatchdogTask::parseCommands(ssize_t readLen) {
for (ssize_t idx = 0; idx < readLen; idx++) {
char nextChar = buf[idx];
// Cancel request
if (nextChar == watchdog::first::CANCEL_CHAR) {
resultQueue.push(LoopResult::CANCEL_REQ);
} else if (nextChar == watchdog::first::SUSPEND_CHAR) {
// Suspend request
resultQueue.push(LoopResult::SUSPEND_REQ);
} else if (nextChar == watchdog::first::START_CHAR) {
if (idx < readLen - 1 and static_cast<char>(buf[idx + 1]) == watchdog::second::WATCH_FLAG) {
resultQueue.push(LoopResult::START_WITH_WATCH_REQ);
idx++;
continue;
}
resultQueue.push(LoopResult::START_REQ);
} else if (nextChar == watchdog::first::IDLE_CHAR) {
resultQueue.push(LoopResult::OK);
}
}
// Everything else: All working as expected
}
int WatchdogTask::performRunningOperation() {
if (state != States::RUNNING) {
state = States::RUNNING;
}
if (notRunningStart.has_value()) {
notRunningStart = std::nullopt;
}
if (not obswRunning) {
if (printNotRunningLatch) {
// Reset latch so user can see timeouts
printNotRunningLatch = false;
}
obswRunning = true;
std::cout << "OBSW is running" << std::endl;
#if WATCHDOG_CREATE_FILE_IF_RUNNING == 1
std::cout << "Creating " << watchdog::RUNNING_FILE_NAME << std::endl;
std::error_code e;
if (not std::filesystem::exists(watchdog::RUNNING_FILE_NAME, e)) {
std::ofstream obswRunningFile(watchdog::RUNNING_FILE_NAME);
if (not obswRunningFile.good()) {
std::cerr << "Creating file " << watchdog::RUNNING_FILE_NAME << " failed" << std::endl;
}
}
#endif
}
return 0;
}
int WatchdogTask::performNotRunningOperation(LoopResult type) {
// Latch prevents spam on console
if (not printNotRunningLatch) {
if (type == LoopResult::HUNG_UP) {
std::cout << "OBSW hung up" << std::endl;
} else {
std::cout << "The FIFO timed out, OBSW might not be running" << std::endl;
}
printNotRunningLatch = true;
}
if (not notRunningStart.has_value()) {
notRunningStart = std::chrono::steady_clock::now();
}
if (obswRunning) {
#if WATCHDOG_CREATE_FILE_IF_RUNNING == 1
std::cout << "Removing " << watchdog::RUNNING_FILE_NAME << std::endl;
std::error_code e;
if (std::filesystem::exists(watchdog::RUNNING_FILE_NAME, e)) {
int result = std::remove(watchdog::RUNNING_FILE_NAME.c_str());
if (result != 0) {
std::cerr << "Removing " << watchdog::RUNNING_FILE_NAME << " failed with code " << errno
<< ": " << strerror(errno) << std::endl;
}
}
#endif
obswRunning = false;
}
if (watchingObsw) {
auto timeNotRunning = std::chrono::steady_clock::now() - notRunningStart.value();
if (std::chrono::duration_cast<std::chrono::milliseconds>(timeNotRunning).count() >
watchdog::MAX_NOT_RUNNING_MS) {
std::cout << "Restarting OBSW with systemctl" << std::endl;
std::system("systemctl restart obsw");
}
}
if (type == LoopResult::HUNG_UP) {
using namespace std::chrono_literals;
// Prevent spam
std::this_thread::sleep_for(2000ms);
}
return 0;
}
bool WatchdogTask::stateMachine(LoopResult loopResult) {
using namespace std::chrono_literals;
bool sleep = false;
switch (state) {
case (States::RUNNING): {
switch (loopResult) {
case (LoopResult::TIMEOUT):
case (LoopResult::HUNG_UP): {
performNotRunningOperation(loopResult);
break;
}
case (LoopResult::OK): {
performRunningOperation();
break;
}
case (LoopResult::SUSPEND_REQ): {
if (state == States::RUNNING or state == States::FAULTY) {
std::cout << "Received suspend request, suspending watchdog operations" << std::endl;
state = States::SUSPENDED;
}
performSuspendOperation();
sleep = true;
break;
}
case (LoopResult::CANCEL_REQ): {
std::cout << "Received cancel request, closing watchdog.." << std::endl;
return false;
}
}
}
case (States::FAULTY):
case (States::SUSPENDED):
case (States::NOT_STARTED): {
switch (loopResult) {
case (LoopResult::SUSPEND_REQ): {
// Ignore and also delay
sleep = true;
break;
}
case (LoopResult::START_REQ):
case (LoopResult::START_WITH_WATCH_REQ): {
if (state == States::NOT_STARTED or state == States::FAULTY) {
state = States::RUNNING;
}
if (loopResult == LoopResult::START_REQ) {
std::cout << "Start request without watch request received" << std::endl;
watchingObsw = false;
} else if (loopResult == LoopResult::START_WITH_WATCH_REQ) {
std::cout << "Start request with watch request received. Restarting OBSW if not "
"running for "
<< watchdog::MAX_NOT_RUNNING_MS / 1000 << " seconds" << std::endl;
watchingObsw = true;
}
performRunningOperation();
break;
}
default: {
sleep = true;
}
}
break;
}
}
if (loopResult == LoopResult::FAULT) {
// Configuration error
std::cerr << "Fault has occured in watchdog loop" << std::endl;
// Prevent spam
sleep = true;
}
if (sleep) {
std::this_thread::sleep_for(500ms);
}
return true;
}
int WatchdogTask::performSuspendOperation() { return 0; }