Child process not waking up after a sigsuspend (C) - 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;
}