reworked watchdog

CHANGELOG.md

@@ -16,6 +16,18 @@ will consitute of a breaking change warranting a new major release:
 
 # [unreleased]
 
+## Changed
+
+- Improved the OBSW watchdog by adding a watch functionality. The watch functionality is optional
+  and has to be enabled specifically by the application being watched by the watchdog when
+  starting the watchdog. If the watch functionality is enabled and the OBSW has not pinged
+  the watchdog via the FIFO for 2 minutes, the watchdog will restart the OBSW service via systemd.
+  The primary OBSW will only activate the watch functionality if it is the OBSW inside the
+  `/usr/bin` directory. This allows debugging the system by leaving flashed or manually copied
+  debugging images 2 minutes to start the watchdog without the watch functionality.
+- The SD card prefix is now set earlier inside the `CoreController` constructor
+- The watchdog handling was moved outside the `CoreController` into the main loop.
+
 # [v1.31.1]
 
 ## Fixed

bsp_q7s/core/CMakeLists.txt

@@ -1,4 +1,4 @@
 target_sources(${OBSW_NAME} PRIVATE CoreController.cpp scheduling.cpp
-                                    ObjectFactory.cpp)
+                                    ObjectFactory.cpp WatchdogHandler.cpp)
 
 target_sources(${SIMPLE_OBSW_NAME} PRIVATE scheduling.cpp)

bsp_q7s/core/CoreController.cpp

@@ -33,12 +33,7 @@ xsc::Copy CoreController::CURRENT_COPY = xsc::Copy::NO_COPY;
 
 CoreController::CoreController(object_id_t objectId)
     : ExtendedControllerBase(objectId, 5), opDivider5(5), opDivider10(10), hkSet(this) {
-  ReturnValue_t result = returnvalue::OK;
   try {
-    result = initWatchdogFifo();
-    if (result != returnvalue::OK) {
-      sif::warning << "CoreController::CoreController: Watchdog FIFO init failed" << std::endl;
-    }
     sdcMan = SdCardManager::instance();
     if (sdcMan == nullptr) {
       sif::error << "CoreController::CoreController: SD card manager invalid!" << std::endl;
@@ -47,11 +42,25 @@ CoreController::CoreController(object_id_t objectId)
     if (not BLOCKING_SD_INIT) {
       sdcMan->setBlocking(false);
     }
+    auto sdCard = sdcMan->getPreferredSdCard();
+    if (not sdCard.has_value()) {
+      sif::error << "CoreController::initializeAfterTaskCreation: "
+                    "Issues getting preferred SD card, setting to 0"
+                 << std::endl;
+      sdCard = sd::SdCard::SLOT_0;
+    }
+    sdInfo.active = sdCard.value();
+    sdcMan->setActiveSdCard(sdInfo.active);
+    currMntPrefix = sdcMan->getCurrentMountPrefix();
 
     getCurrentBootCopy(CURRENT_CHIP, CURRENT_COPY);
   } catch (const std::filesystem::filesystem_error &e) {
     sif::error << "CoreController::CoreController: Failed with exception " << e.what() << std::endl;
   }
+  // Add script folder to path
+  char *currentEnvPath = getenv("PATH");
+  std::string updatedEnvPath = std::string(currentEnvPath) + ":/home/root/scripts:/usr/local/bin";
+  setenv("PATH", updatedEnvPath.c_str(), true);
   sdCardCheckCd.timeOut();
   eventQueue = QueueFactory::instance()->createMessageQueue(5, EventMessage::MAX_MESSAGE_SIZE);
 }
@@ -76,7 +85,6 @@ void CoreController::performControlOperation() {
       }
     }
   }
-  performWatchdogControlOperation();
   sdStateMachine();
   performMountedSdCardOperations();
   if (sdCardCheckCd.hasTimedOut()) {
@@ -146,19 +154,6 @@ ReturnValue_t CoreController::initialize() {
 
 ReturnValue_t CoreController::initializeAfterTaskCreation() {
   ReturnValue_t result = returnvalue::OK;
-  auto sdCard = sdcMan->getPreferredSdCard();
-  if (not sdCard) {
-    return returnvalue::FAILED;
-  }
-  sdInfo.active = sdCard.value();
-  if (sdInfo.active == sd::SdCard::NONE) {
-    sif::error << "CoreController::initializeAfterTaskCreation: "
-                  "Issues getting preferred SD card, setting to 0"
-               << std::endl;
-    sdInfo.active = sd::SdCard::SLOT_0;
-  }
-  sdcMan->setActiveSdCard(sdInfo.active);
-  currMntPrefix = sdcMan->getCurrentMountPrefix();
   if (BLOCKING_SD_INIT) {
     result = initSdCardBlocking();
     if (result != returnvalue::OK and result != SdCardManager::ALREADY_MOUNTED) {
@@ -170,12 +165,7 @@ ReturnValue_t CoreController::initializeAfterTaskCreation() {
   if (result != returnvalue::OK) {
     sif::warning << "CoreController::initialize: Version initialization failed" << std::endl;
   }
-  // Add script folder to path
-  char *currentEnvPath = getenv("PATH");
-  std::string updatedEnvPath = std::string(currentEnvPath) + ":/home/root/scripts:/usr/local/bin";
-  setenv("PATH", updatedEnvPath.c_str(), true);
   updateProtInfo();
-  initPrint();
   return ExtendedControllerBase::initializeAfterTaskCreation();
 }
 
@@ -839,36 +829,6 @@ void CoreController::getCurrentBootCopy(xsc::Chip &chip, xsc::Copy &copy) {
   copy = static_cast<xsc::Copy>(xscCopy);
 }
 
-ReturnValue_t CoreController::initWatchdogFifo() {
-  if (not std::filesystem::exists(watchdog::FIFO_NAME)) {
-    // Still return returnvalue::OK for now
-    sif::info << "Watchdog FIFO " << watchdog::FIFO_NAME << " does not exist, can't initiate"
-              << " watchdog" << std::endl;
-    return returnvalue::OK;
-  }
-  // Open FIFO write only and non-blocking to prevent SW from killing itself.
-  watchdogFifoFd = open(watchdog::FIFO_NAME.c_str(), O_WRONLY | O_NONBLOCK);
-  if (watchdogFifoFd < 0) {
-    if (errno == ENXIO) {
-      watchdogFifoFd = RETRY_FIFO_OPEN;
-      sif::info << "eive-watchdog not running. FIFO can not be opened" << std::endl;
-    } else {
-      sif::error << "Opening pipe " << watchdog::FIFO_NAME << " write-only failed with " << errno
-                 << ": " << strerror(errno) << std::endl;
-      return returnvalue::FAILED;
-    }
-  }
-  return returnvalue::OK;
-}
-
-void CoreController::initPrint() {
-#if OBSW_VERBOSE_LEVEL >= 1
-  if (watchdogFifoFd > 0) {
-    sif::info << "Opened watchdog FIFO successfully.." << std::endl;
-  }
-#endif
-}
-
 ReturnValue_t CoreController::actionXscReboot(const uint8_t *data, size_t size) {
   if (size < 1) {
     return HasActionsIF::INVALID_PARAMETERS;
@@ -1223,36 +1183,6 @@ ReturnValue_t CoreController::handleProtInfoUpdateLine(std::string nextLine) {
   return returnvalue::OK;
 }
 
-void CoreController::performWatchdogControlOperation() {
-  // Only perform each fifth iteration
-  if (watchdogFifoFd != 0 and opDivider5.check()) {
-    if (watchdogFifoFd == RETRY_FIFO_OPEN) {
-      // Open FIFO write only and non-blocking
-      watchdogFifoFd = open(watchdog::FIFO_NAME.c_str(), O_WRONLY | O_NONBLOCK);
-      if (watchdogFifoFd < 0) {
-        if (errno == ENXIO) {
-          watchdogFifoFd = RETRY_FIFO_OPEN;
-          // No printout for now, would be spam
-          return;
-        } else {
-          sif::error << "Opening pipe " << watchdog::FIFO_NAME << " write-only failed with "
-                     << errno << ": " << strerror(errno) << std::endl;
-          return;
-        }
-      }
-      sif::info << "Opened " << watchdog::FIFO_NAME << " successfully" << std::endl;
-    } else if (watchdogFifoFd > 0) {
-      // Write to OBSW watchdog FIFO here
-      const char writeChar = 'a';
-      ssize_t writtenBytes = write(watchdogFifoFd, &writeChar, 1);
-      if (writtenBytes < 0) {
-        sif::error << "Errors writing to watchdog FIFO, code " << errno << ": " << strerror(errno)
-                   << std::endl;
-      }
-    }
-  }
-}
-
 void CoreController::performMountedSdCardOperations() {
   auto mountedSdCardOp = [&](sd::SdCard sdCard, std::string mntPoint) {
     if (not performOneShotSdCardOpsSwitch) {

bsp_q7s/core/CoreController.h

@@ -162,9 +162,6 @@ class CoreController : public ExtendedControllerBase {
  private:
   static constexpr MutexIF::TimeoutType TIMEOUT_TYPE = MutexIF::TimeoutType::WAITING;
   static constexpr uint32_t MUTEX_TIMEOUT = 20;
-  // Designated value for rechecking FIFO open
-  static constexpr int RETRY_FIFO_OPEN = -2;
-  int watchdogFifoFd = 0;
   GpsHyperion::FixMode gpsFix = GpsHyperion::FixMode::UNKNOWN;
 
   // States for SD state machine, which is used in non-blocking mode
@@ -260,7 +257,6 @@ class CoreController : public ExtendedControllerBase {
   ReturnValue_t performSdCardCheck();
   ReturnValue_t timeFileHandler();
   ReturnValue_t initBootCopyFile();
-  ReturnValue_t initWatchdogFifo();
   ReturnValue_t initSdCardBlocking();
   bool startSdStateMachine(sd::SdCard targetActiveSd, SdCfgMode mode, MessageQueueId_t commander,
                            DeviceCommandId_t actionId);
@@ -285,8 +281,6 @@ class CoreController : public ExtendedControllerBase {
 
   ReturnValue_t gracefulShutdownTasks(xsc::Chip chip, xsc::Copy copy, bool& protOpPerformed);
 
-  void performWatchdogControlOperation();
-
   ReturnValue_t handleProtInfoUpdateLine(std::string nextLine);
   int handleBootCopyProtAtIndex(xsc::Chip targetChip, xsc::Copy targetCopy, bool protect,
                                 bool& protOperationPerformed, bool selfChip, bool selfCopy,

bsp_q7s/core/WatchdogHandler.cpp

@@ -0,0 +1,84 @@
+#include "WatchdogHandler.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <cerrno>
+#include <cstring>
+#include <filesystem>
+
+#include "fsfw/serviceinterface.h"
+#include "watchdog/definitions.h"
+
+WatchdogHandler::WatchdogHandler() {}
+
+void WatchdogHandler::periodicOperation() {
+  if (watchdogFifoFd != 0) {
+    if (watchdogFifoFd == RETRY_FIFO_OPEN) {
+      // Open FIFO write only and non-blocking
+      watchdogFifoFd = open(watchdog::FIFO_NAME.c_str(), O_WRONLY | O_NONBLOCK);
+      if (watchdogFifoFd < 0) {
+        if (errno == ENXIO) {
+          watchdogFifoFd = RETRY_FIFO_OPEN;
+          // No printout for now, would be spam
+          return;
+        } else {
+          sif::error << "Opening pipe " << watchdog::FIFO_NAME << " write-only failed with "
+                     << errno << ": " << strerror(errno) << std::endl;
+          return;
+        }
+      }
+      sif::info << "Opened " << watchdog::FIFO_NAME << " successfully" << std::endl;
+      performStartHandling();
+    } else if (watchdogFifoFd > 0) {
+      // Write to OBSW watchdog FIFO here
+      const char writeChar = watchdog::first::IDLE_CHAR;
+      ssize_t writtenBytes = write(watchdogFifoFd, &writeChar, 1);
+      if (writtenBytes < 0) {
+        sif::error << "Errors writing to watchdog FIFO, code " << errno << ": " << strerror(errno)
+                   << std::endl;
+      }
+    }
+  }
+}
+
+ReturnValue_t WatchdogHandler::initialize(bool enableWatchdogFunction) {
+  using namespace std::filesystem;
+  this->enableWatchFunction = enableWatchdogFunction;
+  if (not std::filesystem::exists(watchdog::FIFO_NAME)) {
+    // Still return returnvalue::OK for now
+    sif::info << "Watchdog FIFO " << watchdog::FIFO_NAME << " does not exist, can't initiate"
+              << " watchdog" << std::endl;
+    return returnvalue::OK;
+  }
+  // Open FIFO write only and non-blocking to prevent SW from killing itself.
+  watchdogFifoFd = open(watchdog::FIFO_NAME.c_str(), O_WRONLY | O_NONBLOCK);
+  if (watchdogFifoFd < 0) {
+    if (errno == ENXIO) {
+      watchdogFifoFd = RETRY_FIFO_OPEN;
+      sif::info << "eive-watchdog not running. FIFO can not be opened" << std::endl;
+    } else {
+      sif::error << "Opening pipe " << watchdog::FIFO_NAME << " write-only failed with " << errno
+                 << ": " << strerror(errno) << std::endl;
+      return returnvalue::FAILED;
+    }
+  }
+  return performStartHandling();
+}
+
+ReturnValue_t WatchdogHandler::performStartHandling() {
+  char startBuf[2];
+  size_t writeLen = 1;
+  startBuf[0] = watchdog::first::START_CHAR;
+  if (enableWatchFunction) {
+    writeLen += 1;
+    startBuf[1] = watchdog::second::WATCH_FLAG;
+  }
+  ssize_t writtenBytes = write(watchdogFifoFd, &startBuf, writeLen);
+  if (writtenBytes < 0) {
+    sif::error << "Errors writing to watchdog FIFO, code " << errno << ": " << strerror(errno)
+               << std::endl;
+    return returnvalue::FAILED;
+  }
+  return returnvalue::OK;
+}

bsp_q7s/core/WatchdogHandler.h

@@ -0,0 +1,23 @@
+#ifndef BSP_Q7S_CORE_WATCHDOGHANDLER_H_
+#define BSP_Q7S_CORE_WATCHDOGHANDLER_H_
+
+#include "fsfw/returnvalues/returnvalue.h"
+
+class WatchdogHandler {
+ public:
+  WatchdogHandler();
+
+  ReturnValue_t initialize(bool enableWatchFunction);
+  void periodicOperation();
+
+ private:
+  // Designated value for rechecking FIFO open
+  static constexpr int RETRY_FIFO_OPEN = -2;
+
+  int watchdogFifoFd = 0;
+  bool enableWatchFunction = false;
+
+  ReturnValue_t performStartHandling();
+};
+
+#endif /* BSP_Q7S_CORE_WATCHDOGHANDLER_H_ */

bsp_q7s/obsw.cpp

@@ -9,6 +9,7 @@
 #include <iostream>
 
 #include "OBSWConfig.h"
+#include "bsp_q7s/core/WatchdogHandler.h"
 #include "commonConfig.h"
 #include "core/scheduling.h"
 #include "fsfw/tasks/TaskFactory.h"
@@ -24,6 +25,9 @@ static const char* DEV_STRING = "Xiphos Q7S FM";
 #else
 static const char* DEV_STRING = "Xiphos Q7S EM";
 #endif
+
+WatchdogHandler WATCHDOG_HANDLER;
+
 int obsw::obsw() {
   using namespace fsfw;
   std::cout << "-- EIVE OBSW --" << std::endl;
@@ -44,6 +48,35 @@ int obsw::obsw() {
   }
 #endif
 
+  // Delay the boot if applicable.
+  bootDelayHandling();
+
+  bool initWatchFunction = false;
+  if (std::filesystem::current_path() == "/usr/bin") {
+    initWatchFunction = true;
+  }
+  ReturnValue_t result = WATCHDOG_HANDLER.initialize(initWatchFunction);
+  if (result != returnvalue::OK) {
+    std::cerr << "Initiating EIVE watchdog handler failed" << std::endl;
+  }
+
+  scheduling::initMission();
+
+  // Command the EIVE system to safe mode
+#if OBSW_COMMAND_SAFE_MODE_AT_STARTUP == 1
+  commandEiveSystemToSafe();
+#else
+  announceAllModes();
+#endif
+
+  for (;;) {
+    WATCHDOG_HANDLER.periodicOperation();
+    TaskFactory::delayTask(1000);
+  }
+  return 0;
+}
+
+void obsw::bootDelayHandling() {
   const char* homedir = nullptr;
   homedir = getenv("HOME");
   if (homedir == nullptr) {
@@ -71,31 +104,26 @@ int obsw::obsw() {
     std::cout << "Delaying OBSW start for " << bootDelaySecs << " seconds" << std::endl;
     TaskFactory::delayTask(bootDelaySecs * 1000);
   }
+}
 
-  scheduling::initMission();
+void obsw::commandEiveSystemToSafe() {
-
-  // Command the EIVE system to safe mode
   auto sysQueueId = satsystem::EIVE_SYSTEM.getCommandQueue();
   CommandMessage msg;
-#if OBSW_COMMAND_SAFE_MODE_AT_STARTUP == 1
   ModeMessage::setCmdModeMessage(msg, acs::AcsMode::SAFE, 0);
   ReturnValue_t result =
       MessageQueueSenderIF::sendMessage(sysQueueId, &msg, MessageQueueIF::NO_QUEUE, false);
   if (result != returnvalue::OK) {
     sif::error << "Sending safe mode command to EIVE system failed" << std::endl;
   }
-#else
+}
+
+void obsw::announceAllModes() {
+  auto sysQueueId = satsystem::EIVE_SYSTEM.getCommandQueue();
+  CommandMessage msg;
   ModeMessage::setModeAnnounceMessage(msg, true);
   ReturnValue_t result =
       MessageQueueSenderIF::sendMessage(sysQueueId, &msg, MessageQueueIF::NO_QUEUE, false);
   if (result != returnvalue::OK) {
     sif::error << "Sending safe mode command to EIVE system failed" << std::endl;
   }
-#endif
-
-  for (;;) {
-    /* Suspend main thread by sleeping it. */
-    TaskFactory::delayTask(5000);
-  }
-  return 0;
 }

bsp_q7s/obsw.h

@@ -5,6 +5,10 @@ namespace obsw {
 
 int obsw();
 
-};
+void bootDelayHandling();
+void commandEiveSystemToSafe();
+void announceAllModes();
+
+};  // namespace obsw
 
 #endif /* BSP_Q7S_CORE_OBSW_H_ */

scripts/auto-formatter.sh

@@ -4,6 +4,7 @@ if [[ ! -f README.md ]]; then
 fi
 
 folder_list=(
+  "./watchdog"
   "./mission"
   "./linux"
   "./bsp_q7s"

watchdog/CMakeLists.txt

@@ -1,10 +1,5 @@
-target_sources(${WATCHDOG_NAME} PRIVATE
+target_sources(${WATCHDOG_NAME} PRIVATE main.cpp Watchdog.cpp)
-    main.cpp
-    Watchdog.cpp
-)
 
-target_include_directories(${WATCHDOG_NAME} PRIVATE
+target_include_directories(${WATCHDOG_NAME} PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
-    ${CMAKE_CURRENT_SOURCE_DIR}
-)
 
 install(TARGETS ${WATCHDOG_NAME} RUNTIME DESTINATION bin)

watchdog/Watchdog.cpp

@@ -1,96 +1,61 @@
 #include "Watchdog.h"
-#include "definitions.h"
 
 #include <errno.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <poll.h>
-#include <unistd.h>
 #include <fcntl.h>
+#include <poll.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
 
-#include <iostream>
+#include <cstdlib>
-#include <fstream>
-#include <thread>
 #include <cstring>
 #include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <thread>
 
+#include "definitions.h"
 
-WatchdogTask::WatchdogTask (): fd(0) {
+WatchdogTask::WatchdogTask() : fd(0) {
   int result = 0;
   // Only create the FIFO if it does not exist yet
-    if(not std::filesystem::exists(watchdog::FIFO_NAME)) {
+  if (not std::filesystem::exists(watchdog::FIFO_NAME)) {
     // Permission  666 or rw-rw-rw-
     mode_t mode = DEFFILEMODE;
     result = mkfifo(watchdog::FIFO_NAME.c_str(), mode);
-        if(result != 0) {
+    if (result != 0) {
-            std::cerr << "eive-watchdog: Could not created named pipe at " <<
+      std::cerr << "eive-watchdog: Could not created named pipe at " << watchdog::FIFO_NAME
-                    watchdog::FIFO_NAME << ", error " << errno << ": " << strerror(errno) <<
+                << ", error " << errno << ": " << strerror(errno) << std::endl;
-                    std::endl;
       throw std::runtime_error("eive-watchdog: FIFO creation failed");
     }
 #if WATCHDOG_VERBOSE_LEVEL >= 1
-        std::cout << "eive-watchdog: Pipe at " << watchdog::FIFO_NAME <<
+    std::cout << "eive-watchdog: Pipe at " << watchdog::FIFO_NAME << " created successfully"
-                " created successfully" << std::endl;
+              << std::endl;
 #endif
   }
 }
 
-WatchdogTask::~WatchdogTask() {
+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) {
+  if (fd < 0) {
-        std::cerr << "eive-watchdog: Opening pipe " << watchdog::FIFO_NAME <<
+    std::cerr << "eive-watchdog: Opening pipe " << watchdog::FIFO_NAME << "read-only failed with "
-                "read-only failed with " << errno << ": " << strerror(errno) << std::endl;
+              << errno << ": " << strerror(errno) << std::endl;
     return -1;
   }
-    state = States::RUNNING;
+  state = States::NOT_STARTED;
 
-    while(true) {
+  while (true) {
     WatchdogTask::LoopResult loopResult = watchdogLoop();
-        switch(loopResult) {
+    if (not stateMachine(loopResult)) {
-        case(LoopResult::OK): {
-            performRunningOperation();
       break;
     }
-        case(LoopResult::CANCEL_RQ): {
-            std::cout << "eive-watchdog: Received cancel request, closing watchdog.." << std::endl;
-            return 0;
-        }
-        case(LoopResult::SUSPEND_RQ): {
-            performSuspendOperation();
-            break;
-        }
-        case(LoopResult::TIMEOUT): {
-            performNotRunningOperation(loopResult);
-            break;
-        }
-        case(LoopResult::HUNG_UP): {
-            performNotRunningOperation(loopResult);
-            break;
-        }
-        case(LoopResult::RESTART_RQ): {
-            if(state == States::SUSPENDED or state == States::FAULTY) {
-                performRunningOperation();
-            }
-            break;
-        }
-        case(LoopResult::FAULT): {
-            using namespace std::chrono_literals;
-            // Configuration error
-            std::cerr << "Fault has occured in watchdog loop" << std::endl;
-            // Prevent spam
-            std::this_thread::sleep_for(2000ms);
-
-        }
-        }
   }
   if (close(fd) < 0) {
-        std::cerr << "eive-watchdog: Closing named pipe at " << watchdog::FIFO_NAME <<
+    std::cerr << "eive-watchdog: Closing named pipe at " << watchdog::FIFO_NAME << "failed, error "
-                "failed, error " << errno << ": " << strerror(errno) << std::endl;
+              << errno << ": " << strerror(errno) << std::endl;
   }
   std::cout << "eive-watchdog: Finished" << std::endl;
   return 0;
@@ -102,38 +67,17 @@ WatchdogTask::LoopResult WatchdogTask::watchdogLoop() {
   waiter.fd = fd;
   waiter.events = POLLIN;
 
-    switch(state) {
+  // Only poll one file descriptor with timeout
-    case(States::SUSPENDED): {
+  switch (poll(&waiter, 1, watchdog::TIMEOUT_MS)) {
-        // Sleep, then check whether a restart request was received
+    case (0): {
-        std::this_thread::sleep_for(1000ms);
-        break;
-    }
-    case(States::RUNNING): {
-        // Continue as usual
-        break;
-    }
-    case(States::NOT_STARTED): {
-        // This should not happen
-        std::cerr << "eive-watchdog: State is NOT_STARTED, configuration error" << std::endl;
-        break;
-    }
-    case(States::FAULTY): {
-        // TODO: Not sure what to do yet. Continue for now
-        break;
-    }
-    }
-
-    // 10 seconds timeout, only poll one file descriptor
-    switch(poll(&waiter, 1, watchdog::TIMEOUT_MS)) {
-    case(0): {
       return LoopResult::TIMEOUT;
     }
-    case(1): {
+    case (1): {
       return pollEvent(waiter);
     }
     default: {
-        std::cerr << "eive-watchdog: Unknown poll error at " << watchdog::FIFO_NAME << ", error " <<
+      std::cerr << "eive-watchdog: Unknown poll error at " << watchdog::FIFO_NAME << ", error "
-                errno << ": " << strerror(errno) << std::endl;
+                << errno << ": " << strerror(errno) << std::endl;
       break;
     }
   }
@@ -144,58 +88,55 @@ WatchdogTask::LoopResult WatchdogTask::pollEvent(struct pollfd& waiter) {
   if (waiter.revents & POLLIN) {
     ssize_t readLen = read(fd, buf.data(), buf.size());
     if (readLen < 0) {
-            std::cerr << "eive-watchdog: Read error on pipe " << watchdog::FIFO_NAME <<
+      std::cerr << "eive-watchdog: Read error on pipe " << watchdog::FIFO_NAME << ", error "
-                    ", error " << errno << ": " << strerror(errno) << std::endl;
+                << errno << ": " << strerror(errno) << std::endl;
       return LoopResult::OK;
     }
 #if WATCHDOG_VERBOSE_LEVEL == 2
-        std::cout << "Read " << readLen << " byte(s) on the pipe " << FIFO_NAME
+    std::cout << "Read " << readLen << " byte(s) on the pipe " << FIFO_NAME << std::endl;
-                << std::endl;
 #endif
-        else if(readLen >= 1) {
+    else if (readLen >= 1) {
-            return parseCommandByte(readLen);
+      return parseCommand(readLen);
     }
 
-    }
+  } else if (waiter.revents & POLLERR) {
-    else if(waiter.revents & POLLERR) {
+    std::cerr << "eive-watchdog: Poll error error on pipe " << watchdog::FIFO_NAME << std::endl;
-        std::cerr << "eive-watchdog: Poll error error on pipe " << watchdog::FIFO_NAME <<
-                std::endl;
     return LoopResult::FAULT;
-    }
+  } else if (waiter.revents & POLLHUP) {
-    else if (waiter.revents & POLLHUP) {
     // Writer closed its end
     return LoopResult::HUNG_UP;
   }
   return LoopResult::FAULT;
 }
 
-WatchdogTask::LoopResult WatchdogTask::parseCommandByte(ssize_t readLen) {
+WatchdogTask::LoopResult WatchdogTask::parseCommand(ssize_t readLen) {
-    for(ssize_t idx = 0; idx < readLen; idx++) {
+  char readChar = buf[0];
-        char readChar = buf[idx];
   // Cancel request
-        if(readChar == watchdog::CANCEL_CHAR) {
+  if (readChar == watchdog::first::CANCEL_CHAR) {
-            return LoopResult::CANCEL_RQ;
+    return LoopResult::CANCEL_REQ;
-        }
+  } else if (readChar == watchdog::first::SUSPEND_CHAR) {
-        // Begin request. Does not work if the operation was not suspended before
-        else if(readChar ==  watchdog::RESTART_CHAR) {
-            return LoopResult::RESTART_RQ;
-        }
     // Suspend request
-        else if(readChar == watchdog::SUSPEND_CHAR) {
+    return LoopResult::SUSPEND_REQ;
-            return LoopResult::SUSPEND_RQ;
+  } else if (readChar == watchdog::first::START_CHAR) {
+    if (readLen == 2 and static_cast<char>(buf[1]) == watchdog::second::WATCH_FLAG) {
+      return LoopResult::START_WITH_WATCH_REQ;
+    }
+    return LoopResult::START_REQ;
   }
   // Everything else: All working as expected
-    }
   return LoopResult::OK;
 }
 
 int WatchdogTask::performRunningOperation() {
-    if(state != States::RUNNING) {
+  if (state != States::RUNNING) {
     state = States::RUNNING;
   }
+  if (notRunningStart.has_value()) {
+    notRunningStart = std::nullopt;
+  }
 
-    if(not obswRunning) {
+  if (not obswRunning) {
-        if(printNotRunningLatch) {
+    if (printNotRunningLatch) {
       // Reset latch so user can see timeouts
       printNotRunningLatch = false;
     }
@@ -206,9 +147,8 @@ int WatchdogTask::performRunningOperation() {
     std::cout << "eive-watchdog: Creating " << watchdog::RUNNING_FILE_NAME << std::endl;
     if (not std::filesystem::exists(watchdog::RUNNING_FILE_NAME)) {
       std::ofstream obswRunningFile(watchdog::RUNNING_FILE_NAME);
-            if(not obswRunningFile.good()) {
+      if (not obswRunningFile.good()) {
-                std::cerr << "Creating file " << watchdog::RUNNING_FILE_NAME << " failed"
+        std::cerr << "Creating file " << watchdog::RUNNING_FILE_NAME << " failed" << std::endl;
-                        << std::endl;
       }
     }
 #endif
@@ -218,29 +158,41 @@ int WatchdogTask::performRunningOperation() {
 
 int WatchdogTask::performNotRunningOperation(LoopResult type) {
   // Latch prevents spam on console
-    if(not printNotRunningLatch) {
+  if (not printNotRunningLatch) {
-        if(type == LoopResult::HUNG_UP) {
+    if (type == LoopResult::HUNG_UP) {
       std::cout << "eive-watchdog: FIFO writer hung up!" << std::endl;
-        }
+    } else {
-        else {
       std::cout << "eive-watchdog: The FIFO timed out!" << std::endl;
     }
     printNotRunningLatch = true;
   }
 
-    if(obswRunning) {
+  if (not notRunningStart.has_value()) {
+    notRunningStart = std::chrono::system_clock::now();
+  }
+
+  if (obswRunning) {
 #if WATCHDOG_CREATE_FILE_IF_RUNNING == 1
     if (std::filesystem::exists(watchdog::RUNNING_FILE_NAME)) {
       int result = std::remove(watchdog::RUNNING_FILE_NAME.c_str());
-            if(result != 0) {
+      if (result != 0) {
-                std::cerr << "Removing " << watchdog::RUNNING_FILE_NAME << " failed with code " <<
+        std::cerr << "Removing " << watchdog::RUNNING_FILE_NAME << " failed with code " << errno
-                        errno << ": " << strerror(errno) << std::endl;
+                  << ": " << strerror(errno) << std::endl;
       }
     }
 #endif
     obswRunning = false;
   }
-    if(type == LoopResult::HUNG_UP) {
+
+  if (watchingObsw) {
+    auto timeNotRunning = std::chrono::system_clock::now() - notRunningStart.value();
+    if (std::chrono::duration_cast<std::chrono::milliseconds>(timeNotRunning).count() >
+        watchdog::MAX_NOT_RUNNING_MS) {
+      std::cout << "Restarting OBSW" << 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);
@@ -248,11 +200,77 @@ int WatchdogTask::performNotRunningOperation(LoopResult type) {
   return 0;
 }
 
-int WatchdogTask::performSuspendOperation() {
+bool WatchdogTask::stateMachine(LoopResult loopResult) {
-    if(state == States::RUNNING or state == States::FAULTY) {
+  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 << "eive-watchdog: Suspending watchdog operations" << std::endl;
-        watchdogRunning = false;
             state = States::SUSPENDED;
           }
-    return 0;
+          performSuspendOperation();
+          sleep = true;
+          break;
+        }
+        case (LoopResult::CANCEL_REQ): {
+          std::cout << "eive-watchdog: 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;
+          }
+          std::cout << "Watch request received. Restarting OBSW if not running for "
+                    << watchdog::MAX_NOT_RUNNING_MS / 1000 << " seconds" << std::endl;
+          if (loopResult == LoopResult::START_REQ) {
+            watchingObsw = false;
+          } else if (loopResult == LoopResult::START_WITH_WATCH_REQ) {
+            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(1000ms);
+  }
+  return true;
 }
+
+int WatchdogTask::performSuspendOperation() { return 0; }

watchdog/Watchdog.h

@@ -2,23 +2,21 @@
 #define WATCHDOG_WATCHDOG_H_
 
 #include <array>
+#include <chrono>
 #include <cstdint>
+#include <optional>
 #include <string>
 
 class WatchdogTask {
-public:
+ public:
-    enum class States {
+  enum class States { NOT_STARTED, RUNNING, SUSPENDED, FAULTY };
-        NOT_STARTED,
-        RUNNING,
-        SUSPENDED,
-        FAULTY
-    };
 
   enum class LoopResult {
     OK,
-        SUSPEND_RQ,
+    START_REQ,
-        CANCEL_RQ,
+    START_WITH_WATCH_REQ,
-        RESTART_RQ,
+    SUSPEND_REQ,
+    CANCEL_REQ,
     TIMEOUT,
     HUNG_UP,
     FAULT
@@ -29,18 +27,23 @@ public:
   virtual ~WatchdogTask();
 
   int performOperation();
-private:
+
+ private:
   int fd = 0;
 
   bool obswRunning = false;
-    bool watchdogRunning = false;
+  bool watchingObsw = false;
   bool printNotRunningLatch = false;
   std::array<uint8_t, 64> buf;
+  std::optional<std::chrono::time_point<std::chrono::system_clock>> notRunningStart;
   States state = States::NOT_STARTED;
 
+  // Primary loop. Takes care of delaying, and reading from the communication pipe and translating
+  // messages to loop results.
   LoopResult watchdogLoop();
+  bool stateMachine(LoopResult result);
   LoopResult pollEvent(struct pollfd& waiter);
-    LoopResult parseCommandByte(ssize_t readLen);
+  LoopResult parseCommand(ssize_t readLen);
 
   int performRunningOperation();
   int performNotRunningOperation(LoopResult type);

watchdog/definitions.h

@@ -5,17 +5,31 @@
 
 namespace watchdog {
 
+namespace first {
+
+// Start or restart character
+static constexpr char START_CHAR = 'b';
 // Suspend watchdog operations temporarily
 static constexpr char SUSPEND_CHAR = 's';
-// Resume watchdog operations
-static constexpr char RESTART_CHAR = 'b';
 // Causes the watchdog to close down
 static constexpr char CANCEL_CHAR = 'c';
+static constexpr char IDLE_CHAR = 'i';
+
+}  // namespace first
+
+namespace second {
+
+// Supplied with the start character. This will instruct the watchdog to actually watch
+// the OBSW is runnng all the time.
+static constexpr char WATCH_FLAG = 'w';
+}  // namespace second
 
 static constexpr int TIMEOUT_MS = 5 * 1000;
+// 2 minutes
+static constexpr unsigned MAX_NOT_RUNNING_MS = 2 * 60 * 1000;
 const std::string FIFO_NAME = "/tmp/watchdog-pipe";
 const std::string RUNNING_FILE_NAME = "/tmp/obsw-running";
 
-}
+}  // namespace watchdog
 
 #endif /* WATCHDOG_DEFINITIONS_H_ */

watchdog/main.cpp

@@ -1,7 +1,7 @@
-#include "Watchdog.h"
-
 #include <iostream>
 
+#include "Watchdog.h"
+
 /**
  * @brief   This watchdog application uses a FIFO to check whether the OBSW is still running.
  *          It checks whether the OBSW writes to the the FIFO regularly.
@@ -11,14 +11,12 @@ int main() {
   try {
     WatchdogTask watchdogTask;
     int result = watchdogTask.performOperation();
-        if(result != 0) {
+    if (result != 0) {
       return result;
     }
-    }
+  } catch (const std::runtime_error& e) {
-    catch(const std::runtime_error& e) {
     std::cerr << "eive-watchdog: Run time exception " << e.what() << std::endl;
     return -1;
   }
   return 0;
 }
-