#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h> /* Definition of AT_* constants */
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <signal.h>

static const char *kat = "/tmp/FIFO-TMP-SERWER";
static const char *kat_1 = "/tmp/FIFO-TMP-1-";
static const char *kat_2 = "/tmp/FIFO-TMP-2-";

int f, f1, f2, f_temp;
void end()
{
    close(f);
    close(f1);
    close(f2);
    unlink(kat);
    exit(0);
}

int main()
{
    pid_t pid;
    char kat_1_pid[100];
    char kat_2_pid[100];
    signal(SIGTERM, end);
    signal(SIGINT, end);
    strcpy(kat_1_pid, kat_1);
    strcpy(kat_2_pid, kat_2);
    if (mkfifo(kat, 0600) == -1)
    {
        printf("mkfifo open error\n");
        return;
    }
    if ((f = open(kat, O_RDONLY)) == -1)// || (f_temp = open(kat, O_WRONLY)) == -1)
    {
        unlink(kat);
        printf("kat open error\n");
        return;
    }
    for (;;)
    {
        int readres = read(f, &pid, sizeof(pid_t));
        if(readres == -1){
            printf("read error\n");
            continue;
        }else if(readres == 0){
            continue;
        }
        pid_t pid_c;
        if((pid_c = fork()) != -1){
            if(pid_c == 0){
                printf("pid: %d\n", pid);
                sprintf(kat_1_pid + strlen(kat_1), "%d", pid);
                sprintf(kat_2_pid + strlen(kat_2), "%d", pid);
                if ((f2 = open(kat_2_pid, O_RDONLY)) == -1)
                {
                    // unlink(kat);
                    close(f);
                    printf("kat2 open error\n");
                    return -1;
                }
                printf("f2 open\n");
                if ((f1 = open(kat_1_pid, O_WRONLY)) == -1)
                {
                    // unlink(kat);
                    close(f2);
                    close(f);
                    printf("kat1 open error\n");
                    return -1;
                }
                printf("f1 open\n");
                double d2, d;
                read(f2, &d, sizeof(double));
                d2 = d * d;
                printf("d1: %f d2: %f\n", d, d2);
                write(f1, &d2, sizeof(double));
                close(f1);
                close(f2);
                close(f);
                return 0;
            }else{
                wait(pid_c);
            }
        }
    }
}