text: /**
  ********************************************************************************
  \file   timer-linuxuser.c
  
  \brief  Implementation of user timer module for Linux userspace
  
  This file contains the implementation of the user timer module for Linux
  userspace. This implementation uses the posix timer interface.
  
  \ingroup module_timeru
  *******************************************************************************/
  
  /*------------------------------------------------------------------------------
  Copyright (c) 2016, B&R Industrial Automation GmbH
  Copyright (c) 2013, SYSTEC electronic GmbH
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
      * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
      * Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
      * Neither the name of the copyright holders nor the
        names of its contributors may be used to endorse or promote products
        derived from this software without specific prior written permission.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDERS BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  ------------------------------------------------------------------------------*/
  
  //------------------------------------------------------------------------------
  // includes
  //------------------------------------------------------------------------------
  #include <common/oplkinc.h>
  #include <user/timeru.h>
  #include <user/eventu.h>
  
  #include <stdio.h>
  #include <unistd.h>
  #include <pthread.h>
  #include <semaphore.h>
  #include <signal.h>
  
  // Needed for debugging to extract thread ID on Linux
  #include <sys/syscall.h>
  
  //============================================================================//
  //            G L O B A L   D E F I N I T I O N S                             //
  //============================================================================//
  
  //------------------------------------------------------------------------------
  // const defines
  //------------------------------------------------------------------------------
  
  //------------------------------------------------------------------------------
  // module global vars
  //------------------------------------------------------------------------------
  
  //------------------------------------------------------------------------------
  // global function prototypes
  //------------------------------------------------------------------------------
  
  //============================================================================//
  //            P R I V A T E   D E F I N I T I O N S                           //
  //============================================================================//
  
  //------------------------------------------------------------------------------
  // const defines
  //------------------------------------------------------------------------------
  
  //------------------------------------------------------------------------------
  // local types
  //------------------------------------------------------------------------------
  typedef struct sTimeruData tTimeruData;
  
  struct sTimeruData
  {
      timer_t             timer;
      tTimerArg           timerArgument;
      tTimeruData*        pNextTimer;
      tTimeruData*        pPrevTimer;
  };
  
  typedef struct
  {
      pthread_t           processThread;
      pthread_mutex_t     mutex;
      tTimeruData*        pFirstTimer;
      tTimeruData*        pLastTimer;
      tTimeruData*        pCurrentTimer;
  } tTimeruInstance;
  
  //------------------------------------------------------------------------------
  // local vars
  //------------------------------------------------------------------------------
  static tTimeruInstance timeruInstance_g;
  
  //------------------------------------------------------------------------------
  // local function prototypes
  //------------------------------------------------------------------------------
  static void         cbTimer(const tTimeruData* pData_p);
  static void*        processThread(void* pArgument_p);
  static void         addTimer(tTimeruData* pData_p);
  static void         removeTimer(tTimeruData* pData_p);
  static void         resetTimerList(void);
  static tTimeruData* getNextTimer(void);
  
  //============================================================================//
  //            P U B L I C   F U N C T I O N S                                 //
  //============================================================================//
  
  //------------------------------------------------------------------------------
  /**
  \brief  Initialize user timers
  
  The function initializes the user timer module.
  
  \return The function returns a tOplkError error code.
  
  \ingroup module_timeru
  */
  //------------------------------------------------------------------------------
  tOplkError timeru_init(void)
  {
      struct sched_param  schedParam;
      int                 retVal;
  
      // reset instance structure
      timeruInstance_g.processThread = 0;
      timeruInstance_g.pFirstTimer = NULL;
      timeruInstance_g.pLastTimer = NULL;
  
      if (pthread_mutex_init(&timeruInstance_g.mutex, NULL) != 0)
      {
          DEBUG_LVL_ERROR_TRACE("%s() couldn't init mutex!\n", __func__);
          return kErrorNoResource;
      }
  
      retVal = pthread_create(&timeruInstance_g.processThread,
                              NULL,
                              processThread,
                              &timeruInstance_g);
      if (retVal != 0)
      {
          DEBUG_LVL_ERROR_TRACE("%s() couldn't create timer thread! (%d)\n",
                                __func__,
                                retVal);
          pthread_mutex_destroy(&timeruInstance_g.mutex);
          return kErrorNoResource;
      }
  
      schedParam.sched_priority = CONFIG_THREAD_PRIORITY_LOW;
      if (pthread_setschedparam(timeruInstance_g.processThread,
                                SCHED_RR,
                                &schedParam) != 0)
      {
          DEBUG_LVL_ERROR_TRACE("%s() couldn't set thread scheduling parameters!\n",
                                __func__);
      }
  
  #if (defined(__GLIBC__) && (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 12))
      pthread_setname_np(timeruInstance_g.processThread, "oplk-timeru");
  #endif
  
      return kErrorOk;
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  Shutdown user timer
  
  The function shuts down the user timer instance.
  
  \return The function returns a tOplkError error code.
  
  \ingroup module_timeru
  */
  //------------------------------------------------------------------------------
  tOplkError timeru_exit(void)
  {
      tTimeruData*    pTimer;
  
      /* Check if the processThread exist */
      if (timeruInstance_g.processThread != 0)
      {
          /* cancel thread */
          pthread_cancel(timeruInstance_g.processThread);
          DEBUG_LVL_TIMERU_TRACE("%s() Waiting for thread to exit...\n", __func__);
  
          /* wait for thread to terminate */
          pthread_join(timeruInstance_g.processThread, NULL);
          DEBUG_LVL_TIMERU_TRACE("%s()Thread exited\n", __func__);
      }
  
      /* free up timer list */
      resetTimerList();
      while ((pTimer = getNextTimer()) != NULL)
      {
          removeTimer(pTimer);
          OPLK_FREE(pTimer);
      }
  
      pthread_mutex_destroy(&timeruInstance_g.mutex);
  
      timeruInstance_g.pFirstTimer = NULL;
      timeruInstance_g.pLastTimer = NULL;
  
      return kErrorOk;
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  User timer process function
  
  This function must be called repeatedly from within the application. It checks
  whether a timer has expired.
  
  \note The function is not used in the Linux userspace implementation!
  
  \return The function returns a tOplkError error code.
  
  \ingroup module_timeru
  */
  //------------------------------------------------------------------------------
  tOplkError timeru_process(void)
  {
      return kErrorOk;
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  Create and set a timer
  
  This function creates a timer, sets up the timeout and saves the
  corresponding timer handle.
  
  \param[out]     pTimerHdl_p         Pointer to store the timer handle.
  \param[in]      timeInMs_p          Timeout in milliseconds.
  \param[in]      pArgument_p         Pointer to user definable argument for timer.
  
  \return The function returns a tOplkError error code.
  
  \ingroup module_timeru
  */
  //------------------------------------------------------------------------------
  tOplkError timeru_setTimer(tTimerHdl* pTimerHdl_p,
                             ULONG timeInMs_p,
                             const tTimerArg* pArgument_p)
  {
      tTimeruData*        pData;
      struct itimerspec   relTime;
      struct itimerspec   curTime;
      struct sigevent     sev;
  
      if (pTimerHdl_p == NULL)
          return kErrorTimerInvalidHandle;
  
      pData = (tTimeruData*)OPLK_MALLOC(sizeof(tTimeruData));
      if (pData == NULL)
          return kErrorNoResource;
  
      OPLK_MEMCPY(&pData->timerArgument, pArgument_p, sizeof(tTimerArg));
  
      addTimer(pData);
  
      sev.sigev_notify = SIGEV_SIGNAL;
      sev.sigev_signo = SIGRTMIN;
      sev.sigev_value.sival_ptr = pData;
      if (timer_create(CLOCK_MONOTONIC, &sev, &pData->timer) == -1)
      {
          DEBUG_LVL_ERROR_TRACE("%s() Error creating timer!\n", __func__);
          OPLK_FREE(pData);
          return kErrorNoResource;
      }
  
      if (timeInMs_p >= 1000)
      {
          relTime.it_value.tv_sec = (timeInMs_p / 1000);
          relTime.it_value.tv_nsec = (timeInMs_p % 1000) * 1000000;
      }
      else
      {
          relTime.it_value.tv_sec = 0;
          relTime.it_value.tv_nsec = timeInMs_p * 1000000;
      }
  
      DEBUG_LVL_TIMERU_TRACE("%s() Set timer: %p, timeInMs_p=%ld\n",
                             __func__,
                             (void*)pData,
                             timeInMs_p);
  
      relTime.it_interval.tv_sec = 0;
      relTime.it_interval.tv_nsec = 0;
  
      if (timer_settime(pData->timer, 0, &relTime, &curTime) < 0)
      {
          DEBUG_LVL_ERROR_TRACE("%s() Error timer_settime!\n", __func__);
          return kErrorTimerNoTimerCreated;
      }
  
      *pTimerHdl_p = (tTimerHdl)pData;
      return kErrorOk;
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  Modifies an existing timer
  
  This function modifies an existing timer. If the timer was not yet created
  it creates the timer and stores the new timer handle at \p pTimerHdl_p.
  
  \param[in,out]  pTimerHdl_p         Pointer to store the timer handle.
  \param[in]      timeInMs_p          Timeout in milliseconds.
  \param[in]      pArgument_p         Pointer to user definable argument for timer.
  
  \return The function returns a tOplkError error code.
  
  \ingroup module_timeru
  */
  //------------------------------------------------------------------------------
  tOplkError timeru_modifyTimer(tTimerHdl* pTimerHdl_p,
                                ULONG timeInMs_p,
                                const tTimerArg* pArgument_p)
  {
      tTimeruData*        pData;
      struct itimerspec   relTime, curTime;
  
      if (pTimerHdl_p == NULL)
          return kErrorTimerInvalidHandle;
  
      // check handle itself, i.e. was the handle initialized before
      if (*pTimerHdl_p == 0)
          return timeru_setTimer(pTimerHdl_p, timeInMs_p, pArgument_p);
  
      pData = (tTimeruData*)*pTimerHdl_p;
  
      if (timeInMs_p >= 1000)
      {
          relTime.it_value.tv_sec = (timeInMs_p / 1000);
          relTime.it_value.tv_nsec = (timeInMs_p % 1000) * 1000000;
      }
      else
      {
          relTime.it_value.tv_sec = 0;
          relTime.it_value.tv_nsec = timeInMs_p * 1000000;
      }
  
      DEBUG_LVL_TIMERU_TRACE("%s() Modify timer:%08x timeInMs_p=%ld\n",
                             __func__,
                             *pTimerHdl_p,
                             timeInMs_p);
  
      relTime.it_interval.tv_sec = 0;
      relTime.it_interval.tv_nsec = 0;
      if (timer_settime(pData->timer, 0, &relTime, &curTime) != 0)
      {
          DEBUG_LVL_ERROR_TRACE("%s() Error timer_settime!\n", __func__);
          return kErrorTimerNoTimerCreated;
      }
  
      // copy the TimerArg after the timer is restarted,
      // so that a timer occurred immediately before timer_settime
      // won't use the new timerArg and
      // therefore the old timer cannot be distinguished from the new one.
      // But if the new timer is too fast, it may get lost.
      OPLK_MEMCPY(&pData->timerArgument, pArgument_p, sizeof(tTimerArg));
  
      return kErrorOk;
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  Delete a timer
  
  This function deletes an existing timer.
  
  \param[in,out]  pTimerHdl_p         Pointer to timer handle of timer to delete.
  
  \return The function returns a tOplkError error code.
  \retval kErrorTimerInvalidHandle    An invalid timer handle was specified.
  \retval kErrorOk                    The timer is deleted.
  
  \ingroup module_timeru
  */
  //------------------------------------------------------------------------------
  tOplkError timeru_deleteTimer(tTimerHdl* pTimerHdl_p)
  {
      tTimeruData*    pData;
  
      if (pTimerHdl_p == NULL)
          return kErrorTimerInvalidHandle;
  
      // check handle itself, i.e. was the handle initialized before
      if (*pTimerHdl_p == 0)
          return kErrorOk;
  
      pData = (tTimeruData*)*pTimerHdl_p;
  
      timer_delete(pData->timer);
      removeTimer(pData);
      OPLK_FREE(pData);
  
      // uninitialize handle
      *pTimerHdl_p = 0;
  
      return kErrorOk;
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  Check for an active timer
  
  This function checks if a timer is active (is running).
  
  \param[in]      timerHdl_p          Handle of timer to check.
  
  \return The function returns TRUE if the timer is active, otherwise FALSE.
  
  \ingroup module_timeru
  */
  //------------------------------------------------------------------------------
  BOOL timeru_isActive(tTimerHdl timerHdl_p)
  {
      const tTimeruData*  pData;
      struct itimerspec   remaining;
  
      // check handle itself, i.e. was the handle initialized before
      if (timerHdl_p == 0)
      {   // timer was not created yet, so it is not active
          return FALSE;
      }
      pData = (const tTimeruData*)timerHdl_p;
  
      // check if timer is running
      timer_gettime(pData->timer, &remaining);
  
      if ((remaining.it_value.tv_sec == 0) && (remaining.it_value.tv_nsec == 0))
          return FALSE;
      else
          return TRUE;
  }
  
  //============================================================================//
  //            P R I V A T E   F U N C T I O N S                               //
  //============================================================================//
  /// \name Private Functions
  /// \{
  
  //------------------------------------------------------------------------------
  /**
  \brief  Timer thread function
  
  This function implements the timer thread function which will be started as
  thread and is responsible for processing expired timers.
  
  \param[in,out]  pArgument_p         Thread argument. Not used!
  
  \return The function returns a thread exit value (always NULL)
  */
  //------------------------------------------------------------------------------
  static void* processThread(void* pArgument_p)
  {
      tTimeruData*    pTimer;
      sigset_t        awaitedSignal;
      siginfo_t       signalInfo;
  
      UNUSED_PARAMETER(pArgument_p);
  
      DEBUG_LVL_TIMERU_TRACE("%s() ThreadId:%d\n", __func__, syscall(SYS_gettid));
  
      sigemptyset(&awaitedSignal);
      sigaddset(&awaitedSignal, SIGRTMIN);
      pthread_sigmask(SIG_BLOCK, &awaitedSignal, NULL);
  
      /* loop forever until thread will be canceled */
      while (1)
      {
          if (sigwaitinfo(&awaitedSignal, &signalInfo) > 0)
          {
              pTimer = (tTimeruData*)signalInfo.si_value.sival_ptr;
              if (pTimer != NULL)
                  /* call callback function of timer */
                  cbTimer(pTimer);
              else
              {
                  DEBUG_LVL_ERROR_TRACE("%s() sival_ptr==NULL code=%d\n",
                                        __func__,
                                        signalInfo.si_code);
              }
          }
      }
  
      DEBUG_LVL_TIMERU_TRACE("%s() Exiting!\n", __func__);
      return NULL;
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  Timer callback function
  
  This function is registered if a timer is started and therefore will be called
  by the timer when it expires.
  
  \param[in]      pData_p             The user defined parameter supplied when starting
                                      the timer.
  */
  //------------------------------------------------------------------------------
  static void cbTimer(const tTimeruData* pData_p)
  {
      tEvent          event;
      tTimerEventArg  timerEventArg;
  
      // call event function
      timerEventArg.timerHdl.handle = (tTimerHdl)pData_p;
      OPLK_MEMCPY(&timerEventArg.argument,
                  &pData_p->timerArgument.argument,
                  sizeof(timerEventArg.argument));
  
      event.eventSink = pData_p->timerArgument.eventSink;
      event.eventType = kEventTypeTimer;
      OPLK_MEMSET(&event.netTime, 0x00, sizeof(tNetTime));
      event.eventArg.pEventArg = &timerEventArg;
      event.eventArgSize = sizeof(timerEventArg);
  
      eventu_postEvent(&event);
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  Add a timer to the timer list
  
  This function adds a new timer to the timer list.
  
  \param[in,out]  pData_p             Pointer to the timer structure.
  */
  //------------------------------------------------------------------------------
  static void addTimer(tTimeruData* pData_p)
  {
      tTimeruData*    pTimerData;
  
      pthread_mutex_lock(&timeruInstance_g.mutex);
  
      if (timeruInstance_g.pFirstTimer == NULL)
      {
          timeruInstance_g.pFirstTimer = pData_p;
          timeruInstance_g.pLastTimer = pData_p;
          pData_p->pPrevTimer = NULL;
          pData_p->pNextTimer = NULL;
      }
      else
      {
          pTimerData = timeruInstance_g.pLastTimer;
          pTimerData->pNextTimer = pData_p;
          pData_p->pPrevTimer = pTimerData;
          pData_p->pNextTimer = NULL;
          timeruInstance_g.pLastTimer = pData_p;
      }
  
      pthread_mutex_unlock(&timeruInstance_g.mutex);
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  Remove a timer from the timer list
  
  This function removes a new timer from the timer list.
  
  \param[in,out]  pData_p             Pointer to the timer structure.
  */
  //------------------------------------------------------------------------------
  static void removeTimer(tTimeruData* pData_p)
  {
      tTimeruData*    pTimerData;
  
      pthread_mutex_lock(&timeruInstance_g.mutex);
  
      if (pData_p->pPrevTimer == NULL)          // first one
      {
          timeruInstance_g.pFirstTimer = pData_p->pNextTimer;
          pTimerData = pData_p->pNextTimer;
          if (pTimerData != NULL)
              pTimerData->pPrevTimer = NULL;
      }
      else if (pData_p->pNextTimer == NULL)     // last one
      {
          timeruInstance_g.pLastTimer = pData_p->pPrevTimer;
          pTimerData = pData_p->pPrevTimer;
          pTimerData->pNextTimer = NULL;
      }
      else
      {
          pData_p->pPrevTimer->pNextTimer = pData_p->pNextTimer;
          pData_p->pNextTimer->pPrevTimer = pData_p->pPrevTimer;
      }
  
      pthread_mutex_unlock(&timeruInstance_g.mutex);
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  Reset the timer list
  
  This function resets the timer list.
  */
  //------------------------------------------------------------------------------
  static void resetTimerList(void)
  {
      timeruInstance_g.pCurrentTimer = timeruInstance_g.pFirstTimer;
  }
  
  //------------------------------------------------------------------------------
  /**
  \brief  Get next timer from the list
  
  This function gets the next timer from the timer list.
  
  \return     The function returns a pointer to the next timer in the timer list.
  */
  //------------------------------------------------------------------------------
  static tTimeruData* getNextTimer(void)
  {
      tTimeruData*    pTimer;
  
      pTimer = timeruInstance_g.pCurrentTimer;
      if (pTimer != NULL)
          timeruInstance_g.pCurrentTimer = pTimer->pNextTimer;
  
      return pTimer;
  }
  
  /// \}
  