Child process not waking up after a sigsuspend (C)

Question

I have to create a program that generates 2 childs and each of them has to generate a random number. After that the child who generated the lowest number has to send a SIGUSR1 to the other child. In my case i wanna send a SIGCONT to child 1 to wake him up so that he can send SIGUSR1 to the other process but child 1 doesn't wake up.. any help? Thanks in advance.

#include <unistd.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <stdbool.h>

#define N 2

int getRand(int upper)
{   
    srand(time(0)); 
    int random;
    random = rand() % upper;
    return random;
}

void sighandler(int signo)
{
    if (signo == SIGUSR1)
    {
        printf("Received SIGUSR1, my PID is %d\n\n", getpid());
        exit(0);
    }

    if (signo == SIGUSR2)
    {
        printf("Received SIGUSR2.. I woke up! (My PID is %d)\n\n", getpid());
    }
}

int main (int argc, char **argv)
{   
    int i, r, m, b;
    int status = 0;
    int tabcpid[N], ppid, wpid;
    int fd[2], fdbool[2]; //fd [0 = read] [1 = write]
    sigset_t set, zeromask;
    struct sigaction action;

    //Gestione segnali
    sigemptyset(&zeromask);
    sigemptyset(&action.sa_mask);
    action.sa_handler = sighandler;
    action.sa_flags = 0;
    sigemptyset(&set);
    sigaddset(&set, SIGUSR1);
    sigprocmask(SIG_BLOCK, &set, NULL);
    if (sigaction(SIGUSR1, &action, NULL) == -1)
    {
        perror("Error while doing sigaction.\n\n");
    }

    if (pipe(fd) == -1)
    {
        printf("Error opening pipe fd!\n\n");
        exit(1);
    }

    if (pipe(fdbool) == -1)
    {
        printf("Error opening pipe fdbool!\n\n");
        exit(1);
    }

    printf("\nPipes opened successfully. Forking ...\n\n");

    sleep(2);

    for (i = 0; i < N; i++)
    {
        if ((tabcpid[i] = fork()) == 0) //Child code
        {
            int n = atoi(argv[1]);
            m = getRand(n);
            b = 20;
            ppid = getppid();
            printf("I'm the son process #%d with PID: %d\n", i + 1, getpid());
            printf("Random number in interval 0 - %d: %d\n\n", n, m);
            sleep(2);
            if (i == 0)
            {       
                close(fd[0]);
                write(fd[1], &m, sizeof(int));
                close(fd[1]);

                printf("Suspending..\n\n");

                sigsuspend(&zeromask);
            
                printf("So' ripartitoo\n\n");

                /*
                close(fdbool[1]);   
                read(fdbool[0], &b, sizeof(int));
                close(fdbool[0]);

                printf("--- b value: %d\n\n", b);
                
                if (b == 0) 
                {
                    printf("I'm the process %d and I got the lowest number, SIGUSR1 sent to my brother.\n\n", getpid());
                    kill(tabcpid[1], SIGUSR1);
                }
                sleep(2);
                */  
            }
            else
            {
                close(fd[1]);   
                read(fd[0], &r, sizeof(int));
                close(fd[0]);

                int lower = (r < m) ? r : m;
                int igotlower = (m < r) ? 1 : 0;

                printf("--- igotlower value: %d\n\n", igotlower);

                close(fdbool[0]);
                write(fdbool[1], &igotlower, sizeof(int));
                close(fdbool[1]);               

                //printf("Got %d from other child process, while i got %d.\nThe smallest number is %d.\nMy PID is %d and the other process' PID is %d.\n\n", r, m, lower, getpid(), tabcpid[0]);
                //sleep(2);
                
                if (igotlower == 1)
                {
                    printf("I'm the process %d and I got the lowest number, SIGUSR1 sent to my brother..\n\n", getpid());
                    kill(tabcpid[0], SIGUSR1);
                    sigsuspend(&zeromask);
                }
                else
                {
                    printf("I'm sending SIGCONT to %d\n\n", tabcpid[0]);
                    kill(tabcpid[0], SIGCONT);
                    sigsuspend(&zeromask);
                }
            }
            sleep(2);   
        }
        sleep(2);
    }

    wait(&status);

    close(fdbool[1]);   
    read(fdbool[0], &b, sizeof(int));
    close(fdbool[0]);

    kill(tabcpid[b], SIGUSR1);
    wait(&status);

    printf("It's me the father... it's all over, we're done!\n\n");
    sleep(2);
    return 0;
}