client.c

#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <semaphore.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <fcntl.h>

#define BUF_SIZE 512

const char* read_semaphore = "read_semaphore";
const char* write_semaphore = "write_semaphore";

sem_t* open_sem(const char* sem_name)
{
    sem_t* sem = sem_open(sem_name, 0); // open existing semaphore
    if (sem == SEM_FAILED)
    {
        fprintf(stderr, "Can't create a semaphore\n");
        return NULL;
    }

    return sem;
}

sem_t* read_sem = NULL;
sem_t* write_sem = NULL;

void sig_handler(int signum)
{
    sem_close(read_sem);
    sem_close(write_sem);
    exit(EXIT_SUCCESS);
}

int main(int argc, char** argv)
{
    read_sem = open_sem(read_semaphore);
    write_sem = open_sem(write_semaphore);

    struct sigaction act;
    memset(&act, 0, sizeof(struct sigaction));
    act.sa_handler = sig_handler;

    if (sigaction(SIGTERM, &act, NULL) == -1)
    {
        fprintf(stdout, "Sigaction failed\n");
        exit(EXIT_FAILURE);
    }

    char string[BUF_SIZE];

    while (1)
    {
        sem_wait(read_sem);

        read(0, string, BUF_SIZE);
        puts(string);

        sem_post(write_sem);
    }

    exit(EXIT_SUCCESS);
}