+#define _GNU_SOURCE
+#define _XOPEN_SOURCE 600
+
+#include <sched.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "app_def.h"
+
+pthread_mutex_t shared_with_hi_mtx;
+pthread_mutex_t shared_with_lo_mtx;
+
+sem_t release_hi_sem;
+sem_t release_mid_sem;
+sem_t release_lo_sem;
+
+pthread_t hi_task_id;
+pthread_t mid_task_id;
+pthread_t lo_task_id;
+
+
+void bad_status(int status, int fail_level, const char *text)
+{
+ printf("ERROR: %s status %d\n", text, status);
+ exit(1);
+}
+
+
+void block_delay(int delay)
+{
+ volatile int l;
+
+ while(delay--) {
+ l = 100000;
+ while(l--);
+ }
+}
+
+
+void *hi_task(void *arg)
+{
+ int status;
+
+ printf("THI created\n"); fflush(stdout);
+ while(1){
+ status=sem_wait(&release_hi_sem);
+ if(status!=0) bad_status(status, 0, "sem_wait RHI from THI");
+ printf("THI released (RHI)\n"); fflush(stdout);
+
+ status=pthread_mutex_lock(&shared_with_hi_mtx);
+ if(status!=0) bad_status(status, 0, "pthread_mutex_lock SHI from THI");
+ printf("THI obtained SHI\n"); fflush(stdout);
+
+ block_delay(100);
+
+ printf("THI going to release SHI\n"); fflush(stdout);
+ status=pthread_mutex_unlock(&shared_with_hi_mtx);
+ if(status!=0) bad_status(status, 0, "pthread_mutex_unlock SHI from THI");
+ printf("THI released SHI\n"); fflush(stdout);
+ }
+}
+
+void *mid_task(void *arg)
+{
+ int status;
+
+ printf("TMID created\n"); fflush(stdout);
+ while(1){
+ status=sem_wait(&release_mid_sem);
+ if(status!=0) bad_status(status, 0, "sem_wait RMID from TMID");
+ printf("MID released (RMID)\n"); fflush(stdout);
+
+ block_delay(100);
+
+ printf("MID going to sleep\n"); fflush(stdout);
+ }
+}
+
+void *lo_task(void *arg)
+{
+ int status;
+
+ printf("LO created\n"); fflush(stdout);
+ while(1){
+ status=sem_wait(&release_lo_sem);
+ if(status!=0) bad_status(status, 0, "sem_wait RLO from TLO");
+ printf("TLO released (RLO)\n"); fflush(stdout);
+
+ status=pthread_mutex_lock(&shared_with_lo_mtx);
+ if(status!=0) bad_status(status, 0, "pthread_mutex_lock SLO from TLO");
+ printf("TLO obtained SLO\n"); fflush(stdout);
+
+ block_delay(100);
+
+ printf("TLO going to release SLO\n"); fflush(stdout);
+ status=pthread_mutex_unlock(&shared_with_lo_mtx);
+ if(status!=0) bad_status(status, 0, "pthread_mutex_unlock SLO from TLO");
+ printf("TLO released SLO\n"); fflush(stdout);
+ }
+}
+
+
+void *Task_1(void *argument)
+{
+ int status;
+ pthread_mutexattr_t mutexattr;
+ pthread_attr_t taskattr;
+ struct sched_param schedparam;
+
+ sleep(1);
+
+ printf("*** Starting up Task_1 ***\n");
+
+ schedparam.sched_priority = sched_get_priority_min(SCHED_FIFO) + TASK_1_PRIORITY;
+ status = pthread_setschedparam(pthread_self(), SCHED_FIFO, &schedparam);
+ if(status!=0) bad_status(status, 0, "pthread_setschedparam" );
+
+ status = pthread_mutexattr_init(&mutexattr);
+ if(status!=0) bad_status(status, 0, "pthread_mutexattr_init" );
+ status=pthread_mutexattr_setprotocol(&mutexattr, PTHREAD_PRIO_INHERIT);
+ if(status!=0) bad_status(status, 0, "pthread_mutexattr_setprotocol" );
+
+ status=pthread_mutex_init(&shared_with_hi_mtx, &mutexattr);
+ if(status!=0) bad_status(status, 0, "pthread_mutex_init SHI" );
+
+ status=pthread_mutex_init(&shared_with_lo_mtx, &mutexattr);
+ if(status!=0) bad_status(status, 0, "pthread_mutex_init SLO" );
+
+ status=sem_init(&release_hi_sem, 0, 0);
+ if(status!=0) bad_status(status, 0, "sem_init RHI" );
+
+ status=sem_init(&release_mid_sem, 0, 0);
+ if(status!=0) bad_status(status, 0, "sem_init RMID" );
+
+ status=sem_init(&release_lo_sem, 0, 0);
+ if(status!=0) bad_status(status, 0, "sem_init RLO" );
+
+ status = pthread_attr_init(&taskattr);
+ if(status!=0) bad_status(status, 0, "pthread_attr_init" );
+ status = pthread_attr_setinheritsched(&taskattr, PTHREAD_EXPLICIT_SCHED);
+ if(status!=0) bad_status(status, 0, "pthread_attr_setinheritsched" );
+ status = pthread_attr_setschedpolicy(&taskattr, SCHED_FIFO);
+ if(status!=0) bad_status(status, 0, "pthread_attr_setschedpolicy" );
+
+ schedparam.sched_priority = sched_get_priority_min(SCHED_FIFO) + TASK_HI_PRIORITY;
+ status = pthread_attr_setschedparam(&taskattr, &schedparam);
+ if(status!=0) bad_status(status, 0, "pthread_attr_setschedparam" );
+
+ status = pthread_create(&hi_task_id, &taskattr, hi_task, NULL);
+ if(status!=0) bad_status(status, 0, "pthread_create THI\n");
+
+ schedparam.sched_priority = sched_get_priority_min(SCHED_FIFO) + TASK_MID_PRIORITY;
+ status = pthread_attr_setschedparam(&taskattr, &schedparam);
+ if(status!=0) bad_status(status, 0, "pthread_attr_setschedparam" );
+
+ status = pthread_create(&hi_task_id, &taskattr, mid_task, NULL);
+ if(status!=0) bad_status(status, 0, "pthread_create TMID\n");
+
+ schedparam.sched_priority = sched_get_priority_min(SCHED_FIFO) + TASK_LO_PRIORITY;
+ status = pthread_attr_setschedparam(&taskattr, &schedparam);
+ if(status!=0) bad_status(status, 0, "pthread_attr_setschedparam" );
+
+ status = pthread_create(&hi_task_id, &taskattr, lo_task, NULL);
+ if(status!=0) bad_status(status, 0, "pthread_create TLO\n");
+
+ sleep(1);
+
+ while(1){
+
+ status=pthread_mutex_lock(&shared_with_lo_mtx);
+ if(status!=0) bad_status(status, 0, "pthread_mutex_lock SLO");
+ printf("1 obtained SLO\n"); fflush(stdout);
+
+ printf("1 going to release RLO\n"); fflush(stdout);
+ status=sem_post(&release_lo_sem);
+ if(status!=0) bad_status(status, 0, "sem_post RLO");
+
+ status=pthread_mutex_lock(&shared_with_hi_mtx);
+ if(status!=0) bad_status(status, 0, "pthread_mutex_lock SHI");
+ printf("1 obtained SHI\n"); fflush(stdout);
+
+ printf("1 going to release RHI\n"); fflush(stdout);
+ status=sem_post(&release_hi_sem);
+ if(status!=0) bad_status(status, 0, "sem_post RHI");
+
+ sleep(1);
+
+ printf("1 going to release RMID\n"); fflush(stdout);
+ status=sem_post(&release_mid_sem);
+ if(status!=0) bad_status(status, 0, "sem_post RMID");
+
+ block_delay(100);
+
+ printf("1 going to release SHI\n"); fflush(stdout);
+ status=pthread_mutex_unlock(&shared_with_hi_mtx);
+ if(status!=0) bad_status(status, 0, "pthread_mutex_unlock SHI");
+
+ block_delay(100);
+
+ printf("1 going to release SLO\n"); fflush(stdout);
+ status=pthread_mutex_unlock(&shared_with_lo_mtx);
+ if(status!=0) bad_status(status, 0, "pthread_mutex_unlock SLO");
+ printf("1 released both SHI and SLO\n"); fflush(stdout);
+
+ block_delay(100);
+
+ printf("1 going to sleep\n"); fflush(stdout);
+ sleep(1);
+ }
+}
+
+#ifndef COMPILE_FOR_RTEMS
+
+int main(int argc, char *argv[])
+{
+ Task_1(NULL);
+ return 0;
+}
+
+#endif /*COMPILE_FOR_RTEMS*/