diff options
Diffstat (limited to 'Master/Real-Time Systems/Praktikum1/Aufgabe1/src')
| -rw-r--r-- | Master/Real-Time Systems/Praktikum1/Aufgabe1/src/main.cpp | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/Master/Real-Time Systems/Praktikum1/Aufgabe1/src/main.cpp b/Master/Real-Time Systems/Praktikum1/Aufgabe1/src/main.cpp new file mode 100644 index 0000000..65eef37 --- /dev/null +++ b/Master/Real-Time Systems/Praktikum1/Aufgabe1/src/main.cpp @@ -0,0 +1,195 @@ +/* + * main.cpp + * + * Created on: 31.10.2010 + * Author: sven + */ +#include <pthread.h> +#include <semaphore.h> +#include <time.h> +#include <sys/time.h> +#include <signal.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +// debug printing +#ifdef DEBUG_MODE +#include <stdio.h> + #define DEBUG_PRINT(format, args...)\ + {\ + static char message[512];\ + snprintf(message,512,format, ##args);\ + fprintf(stdout, "[%s: %d] : %s\n", __PRETTY_FUNCTION__,__LINE__, message);\ + fflush(stdout);\ + } +#else + #define DEBUG_PRINT(format, args...) +#endif // DEBUG_MODE + +/* + * global variables + */ +sem_t main_block,timer_block; +pthread_t timer_thread; +bool stop_timer_thread = false; +pthread_mutex_t stop_mutex = PTHREAD_MUTEX_INITIALIZER; +// 0 sec +const long TIMER_INTERVAL_SECS = 0; +// 10 msec +const long TIMER_INTERVAL_USECS = 10000; + +struct sigaction timer_action, quit_action; +/* + * function prototypes + */ +void readSensors(); +void initializeClock(); +void initializeMain(); +void WaitForNextCycle(); +void ActuateProcess(); +bool CalculateNewSetValues(); +void Error(); +void* TimerThreadProc(void*); +void timer_handler(int); + +void* TimerThreadProc(void*) { + /** + * Timer code originally from + * http://www.informit.com/articles/article.aspx?p=23618&seqNum=14 + */ + DEBUG_PRINT("entry Process: %d Thread: %lu",(int)getpid(),pthread_self()); + bool stop_me = false; + struct itimerval timer; + /* Install timer_handler as the signal handler for SIGALRM. */ + timer_action.sa_handler = timer_handler; + sigemptyset(&timer_action.sa_mask); + timer_action.sa_flags = 0; + sigaction(SIGALRM,&timer_action,NULL); + + /* Configure the timer to expire after + * TIMER_INTERVAL_SECS + TIMER_INTERVAL_USECS... */ + timer.it_value.tv_sec = TIMER_INTERVAL_SECS; + timer.it_value.tv_usec = TIMER_INTERVAL_USECS; + /* ... and every TIMER_INTERVAL_SECS+TIMER_INTERVAL_USECS after that. */ + timer.it_interval.tv_sec = TIMER_INTERVAL_SECS; + timer.it_interval.tv_usec = TIMER_INTERVAL_USECS; + /* If the timer code is ITIMER_REAL, + * the process is sent a SIGALRM signal after the + * specified wall-clock time has elapsed*/ + setitimer (ITIMER_REAL, &timer, NULL); + while(1) { + pthread_mutex_lock(&stop_mutex); + stop_me = stop_timer_thread; + pthread_mutex_unlock(&stop_mutex); + if(stop_me) { + DEBUG_PRINT("exiting thread Process: %d Thread: %lu",(int)getpid(),pthread_self()); + pthread_exit(NULL); + } + DEBUG_PRINT("waiting for timer_handler Process: %d Thread: %lu",(int)getpid(),pthread_self()); + sem_wait(&timer_block); + DEBUG_PRINT("waking up main Process: %d Thread: %lu",(int)getpid(),pthread_self()); + sem_post(&main_block); + } + DEBUG_PRINT("should never happen Process: %d Thread: %lu",(int)getpid(),pthread_self()); + return NULL; +} + +void timer_handler(int signum) { + DEBUG_PRINT("entry Process: %d Thread: %lu",(int)getpid(),pthread_self()); + static int count = 0; + DEBUG_PRINT("timer expired %d times", ++count); + sem_post(&timer_block); + DEBUG_PRINT("exit"); +} + +void quit_handler(int signum) { + DEBUG_PRINT("entry Process: %d Thread: %lu",(int)getpid(),pthread_self()); + int semval; + pthread_mutex_lock(&stop_mutex); + stop_timer_thread = true; + pthread_mutex_unlock(&stop_mutex); + sem_getvalue(&timer_block,&semval); + if(semval > 0) { + DEBUG_PRINT("waking up timer thread"); + sem_post(&timer_block); + } + pthread_join(timer_thread,NULL); + DEBUG_PRINT("Joined timer thread"); + //clean up + sem_destroy(&timer_block); + sem_destroy(&main_block); + pthread_mutex_destroy(&stop_mutex); + DEBUG_PRINT("exit"); + exit(EXIT_SUCCESS); +} + +void WaitForNextCycle() { + DEBUG_PRINT("entry Process: %d Thread: %lu",(int)getpid(),pthread_self()); + sem_wait(&main_block); + DEBUG_PRINT("exit"); +} + +void readSensors() { + DEBUG_PRINT("entry Process: %d Thread: %lu",(int)getpid(),pthread_self()); + struct timeval tv; + struct timezone tz; + struct tm *tm; + gettimeofday(&tv, &tz); + tm=localtime(&tv.tv_sec); + printf(" %d:%02d:%02d %lu \n", tm->tm_hour, tm->tm_min, + tm->tm_sec, tv.tv_usec); + DEBUG_PRINT("exit"); +} +void Error() { + DEBUG_PRINT("entry Process: %d Thread: %lu",(int)getpid(),pthread_self()); + DEBUG_PRINT("exit"); +} +bool CalculateNewSetValues() { + DEBUG_PRINT("entry Process: %d Thread: %lu",(int)getpid(),pthread_self()); + DEBUG_PRINT("exit"); + return true; +} +void ActuateProcess() { + DEBUG_PRINT("entry Process: %d Thread: %lu",(int)getpid(),pthread_self()); + DEBUG_PRINT("exit"); +} +void initializeClock() +{ + DEBUG_PRINT("entry Process: %d Thread: %lu",(int)getpid(),pthread_self()); + pthread_create(&timer_thread,NULL,TimerThreadProc,NULL); + DEBUG_PRINT("exit"); +} + +void initializeMain() { + DEBUG_PRINT("entry Process: %d Thread: %lu",(int)getpid(),pthread_self()); + + /* init semaphore as closed */ + sem_init(&main_block,0,0); + sem_init(&timer_block,0,0); + + /* catch all interesting signals */ + quit_action.sa_handler = quit_handler; + sigemptyset(&quit_action.sa_mask); + quit_action.sa_flags = 0; + sigaction(SIGTERM,&quit_action,NULL); + sigaction(SIGQUIT,&quit_action,NULL); + sigaction(SIGINT,&quit_action,NULL); + sigaction(SIGHUP,&quit_action,NULL); + DEBUG_PRINT("exit"); +} + +int main(int argc, char* argv[]) +{ + initializeMain(); + initializeClock(); + while(1) { + readSensors(); + if(CalculateNewSetValues()) + ActuateProcess(); + else + Error(); + WaitForNextCycle(); + } + return EXIT_SUCCESS; +} |