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

#define MESSAGE_SIZE 100

extern int errno;

char file_name[20];


void parent_process(int pipefd[]){
    char message[MESSAGE_SIZE];
    if(close(pipefd[1]) < 0)
        perror("parent - close write");
    if(read(pipefd[0], message, sizeof(message)) < 0)
        perror("read");

    printf("\nOdebrana wiadomosc:\t\t%s\n", message);

    if(close(pipefd[0]) < 0)
        perror("parent - close read");

    wait(0);
}

void child_process(int pipefd[], char file_name[]){
    char message[MESSAGE_SIZE];

    if(close(pipefd[0]) < 0)
        perror("close read - child");

    int errnum;
    FILE *file = fopen(file_name, "r");

    if(file == NULL){
        errnum = errno;
        strcpy(message, strerror(errnum));
    } else {
        fread(message, sizeof(char), sizeof(message), file);
    }

    printf("Wiadomosc do przekazania:\t%s", message);
    if(write(pipefd[1], message, strlen(message)) < 0)
            perror("child - write content");

    fclose(file);

    exit(0);
}


int main(){
    int pipefd[2];
    if(pipe(pipefd)<0)
        perror("pipe");

    printf("Podaj nazwe pliku: ");
    scanf("%s", file_name);


    int pid = fork();
    if(pid == -1)
        perror("fork");
    if(pid == 0)
        child_process(pipefd, file_name);
    else
        parent_process(pipefd);



    return 0;

}