[Rank 3] Minishell - Fork, Pipe 함수 연습

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   fork_pipe.c                                        :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: jiychoi <jiychoi@student.42seoul.kr>       +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2021/10/02 18:45:39 by jiychoi           #+#    #+#             */
/*   Updated: 2021/10/08 13:44:08 by jiychoi          ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "fork_pipe.h"

char    **pipe_getpath(char *envp[])
{
    int        i;
    char    **path;

    i = -1;
    while (envp[++i])
    {
        if (ft_strnstr(envp[i], "PATH=", 5))
        {
            path = ft_split(envp[i], ':');
            break ;
        }
    }
    i = -1;
    while (path[++i])
        printf("%s\n", path[i]);
    return (path);
}

void    pipe_parent(int fd)
{
    char    buf[100];

    printf("this is parent process %d\n", getpid());
    read(fd, buf, 100);
    printf("%s\n", buf);
}

void    pipe_child(int fd)
{
    printf("this is child process %d\n", getpid());
    write(fd, "Hello World!!!\n", 15);
}

int    main(int argc, char *argv[], char *envp[])
{
    pid_t    pid;
    int        fd[2];

    pipe_getpath(envp);
    printf("%d\n", getpid());
    if (pipe(fd) < 0)
        return (0);
    pid = fork();
    if (pid)
        pipe_parent(fd[0]);
    else
        pipe_child(fd[1]);
}

pipe를 통해 부모 자식 프로세스를 연결했을 때 값이 정상적으로 출력되는지 체크하는 예제