#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
#include <unistd.h>

pthread_barrier_t bar;


void* tester(void *arg)
{
        struct dirent en, *enp;
        DIR *d = opendir("/");
        int r;

        if (d == NULL) {
                perror("opendir() failed");
                return NULL;
        }

        pthread_barrier_wait(&bar);

        do {
                r = readdir_r(d, &en, &enp);
                if (errno != 0)
                {
                        perror("thread tester error");
                        exit(2);
                        break;
                }
        } while (enp != NULL);

        closedir(d);
}

void* checker(void *arg)
{
        pthread_barrier_wait(&bar);
        printf("Passed barrier!\n");
}


int main(int argc, char *argv[])
{
        int i, ret, nthreads;
        pthread_t *threads;
        pthread_t th;

        if (argc <= 1)
        {
                printf("Need one argument\n");
                exit(1);
        }

        nthreads = atoi(argv[1]);
        threads = malloc(sizeof(pthread_t) * (nthreads + 1));
        if (threads == NULL) {
                fprintf(stderr, "malloc failed!\n");
                exit(3);
        }

        printf("Trying with %d threads\n", nthreads);

        if ( (ret = pthread_barrier_init(&bar, NULL, nthreads + 1)) != 0)
        {
                printf("error occurred during pthread_barrier_init, ret = %d\n", ret);
                perror("Or: ");
                exit(1);
        }

        printf("Creating checker thread\n");
        pthread_create(&th, NULL, checker, NULL);

        printf("Creating tester threads\n");


        for (i = 0; i < nthreads; i++) {
                ret = pthread_create(&threads[i], NULL, tester, NULL);
                if (ret != 0)
                        threads[i] = 0;
        }

        //sleep(5);

        printf("Starting join\n");
        for (i = 0; i < nthreads; i++) {
                if (threads[i] != 0)
                        pthread_join(threads[i], NULL);
        }

        printf("All done!\n");
        return 0;
}