Tukukkk

I am getting a segmentation fault within my code, but my main misunderstanding lies within whether i am properly using pthreads as well as semaphores. The usual case, or so i have found online, only uses a single barber to handle his customers. In this situation, i have 3 barbers.

Where might i be making my mistake?

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

#include <unistd.h>

#include <errno.h>



#include <pthread.h>

#include <semaphore.h>



int NUM_BARBERS = 3;

int NUM_CHAIRS = 10;

int NUM_CUSTOMERS = 25;

int CUSTOMER_MAX_INTERVAL = 2;

int HAIRCUT_TIME = 4;



extern int errno;



int chair_availability;



pthread_mutex_t count_lock;

sem_t barber_sem;

sem_t waitingRoom;

sem_t pillow;

sem_t waitCust;



void* get_haircut(void* args){



    int temp;

    int* arg;

    int id;



    arg = (int*) args;

    id = *arg;



    /* Actual logic:

     * - Check (and wait) for an available barber

     * - Once a chair is occupied, get a haircut

     * - Make sure to get out of the chair when we're done!

     *

     * Remember to be careful and protect your concurrent accesses--but

     * don't hold any needless mutexes, or you might risk deadlock!

     *

     * Bonus: do statistics to see e.g. average wait time, average

     * queued customers at any point, etc.

     */



        sem_wait(&waitingRoom);



        //wait for barber to be free

        sem_wait(&barber_sem);





        //When Chair is free

        sem_post(&waitingRoom);



        //Wake barber

        sem_post(&pillow);



        //Getting a haircut, must wait till finished

        sem_wait(&waitCust);



        sem_post(&barber_sem);













    return 0;

}





int main(int argc, char **argv)

{

    int iteration;

    int sleep_time;

    int result;

    int i;

    pthread_t threads[NUM_CUSTOMERS];

    int Number[NUM_CUSTOMERS];

    pthread_t btid;

    int allDone;

    allDone = 0;



//Initializing Semaphores

    sem_init(&waitingRoom, 0, NUM_CHAIRS);

    sem_init(&barber_sem,0,1);

    sem_init(&pillow, 0, 0);

    sem_init(&waitCust,0,0);







    if (argc > 1){

        NUM_BARBERS = atoi(argv[1]);

        if (NUM_BARBERS < 1){

            printf("There must be at least one barbern");

            return(1);

        }

    }

    if (argc > 2){

        NUM_CHAIRS = atoi(argv[2]);

        if (NUM_CHAIRS < 1){

            printf("There must be at least one chairn");

            return(1);

        }

    }

    if (argc > 3){

        NUM_CUSTOMERS = atoi(argv[3]);

        if (NUM_CUSTOMERS < 1){

            printf("There must be at least one customern");

            return(1);

        }

    }

    if (argc > 4){

        CUSTOMER_MAX_INTERVAL = atoi(argv[4]);

        if (CUSTOMER_MAX_INTERVAL < 0){

            printf("The customers cannot come in negative timen");

            return(1);

        }

    }

    if (argc > 5){

        HAIRCUT_TIME = atoi(argv[5]);

        if (HAIRCUT_TIME < 1){

            printf("Haircuts must take at least one secondn");

            return(1);

        }

    }



    printf("Welcome to the barbershop problem!n");

    printf("For this run, we have:n");

    printf("%i Barbersn", NUM_BARBERS);

    printf("%i Chairsn", NUM_CHAIRS);

    printf("%i customers will come in with delay from 0 to %i between them.n", NUM_CUSTOMERS, CUSTOMER_MAX_INTERVAL);

    printf("A haircut takes %i seconds.nn", HAIRCUT_TIME);



    for (i=0; i<NUM_CUSTOMERS; i++) {

        Number[i] = i;

    }

    for (i=0; i<NUM_CUSTOMERS; i++) {

        pthread_join(threads[i], NULL);

        sleep(1);

    }

    printf("Beginning Simulation.nn");

    srand((unsigned int) time(NULL));

    for(iteration=0; iteration<NUM_CUSTOMERS; ++iteration){

        pthread_create(&threads, NULL, get_haircut, (void *)&Number[i]);

        pthread_detach(threads[iteration]);  /* Indicate that the thread shouldn't hold resources */



        sleep(4);

    }



    /* Check (and wait) for any remaining customers */



    //the barber is asleep

    sem_wait(&pillow);



   if(!allDone){ 

       sem_post(&waitCust);

   }

   else{

       printf("The barber is clocking out");

   }

   //All customers serviced

    allDone = 1;

    //Wake to go home

    sem_post(&pillow);

    //Kill barber >:)

    pthread_join(btid,NULL);

    printf("nBarbershop Problem Completedn");

    return(0);

}