zad3

#include <pthread.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>

char mutual[100];
int flag[2];
int thread_id[2];
pthread_mutex_t lock;

void* read_thread(void *arg) {
    char *file_name = (char *)arg;
    int thread_number;
    if(file_name == "/etc/profile")
        thread_number=0;
    else
        thread_number=1;

    thread_id[thread_number]=pthread_self();

    FILE* input=fopen(file_name,"r");

    while(1) {
        pthread_mutex_lock(&lock);
        if(!fgets(mutual, 100, input)){
            flag[thread_number]= (-1);
            pthread_mutex_unlock(&lock);
            break;
        }
        else{
            flag[thread_number]=1;
        }
        while(flag[thread_number]==1)
            usleep(100);
        pthread_mutex_unlock(&lock);
        usleep(100);
    }
}

int main() {
    flag[0]=0;
    flag[1]=0;
    pthread_t reader[2];
    char *prof = "/etc/profile";
    char *pass = "/etc/passwd";
    FILE *fp[2];
    fp[0] = fopen("./KACPER1", "w");
    fp[1] = fopen("./KACPER2", "w");

    if (pthread_mutex_init(&lock, NULL) != 0) {
        printf("\n mutex init has failed\n");
        return 1;
    }

    pthread_create(&reader[0], NULL, &read_thread, (void *)prof);
    pthread_detach(reader[0]);
    pthread_create(&reader[1], NULL, &read_thread, (void *)pass);
    pthread_detach(reader[1]);

    while(1){
        if(flag[0] == 1) {
            fwrite(mutual, sizeof(char), 100, fp[0]);
            printf("%d : %s", thread_id[0], mutual);
            memset(mutual,0,100);
            flag[0] = 0;
        }
        if(flag[1] == 1) {
            fwrite(mutual, sizeof(char), 100, fp[1]);
            printf("%d : %s", thread_id[1], mutual);
            memset(mutual,0,100);
            flag[1] = 0;
        }
        if(flag[0] == -1 && flag[1] == -1)
            break;
        usleep(100);
    }
}