pipe.c

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/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   pipe.c                                             :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: dmdemirk <dmdemirk@student.42london.c      +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2024/06/17 11:04:39 by dmdemirk          #+#    #+#             */
/*   Updated: 2024/11/07 19:48:14 by dmdemirk         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */
 
#include "shell.h"
#include <unistd.h>
#include "libft.h"
#include "execute.h"
#include <stdio.h>
#include <sys/wait.h>
#include "pipe.h"
 
int     builtin_pipe(t_ast *node, t_ms_data *data);
pid_t   execute_child(t_ast *node, t_ms_data *data, \
        int fd[2], int direction);
 
static int  setup_pipe_processes(t_ast *node, t_ms_data *data, \
            pid_t *pid_1, pid_t *pid_2)
{
    int fd[2];
 
    *pid_2 = -1;
    if (pipe(fd) == -1)
        return (ft_perror("pipe"));
    *pid_1 = execute_child(node->left, data, fd, 0);
    if (node->right != NULL)
        *pid_2 = execute_child(node->right, data, fd, 1);
    else
    {
        close(fd[1]);
        data->std_in = fd[0];
        return (WAIT_NEXT_COMMAND);
    }
    close_fds(fd[0], fd[1]);
    return (EXIT_SUCCESS);
}
 
int builtin_pipe(t_ast *node, t_ms_data *data)
{
    pid_t   pid_1;
    pid_t   pid_2;
    int     status_1;
    int     status_2;
    int     setup_result;
 
    status_1 = 0;
    status_2 = 0;
    setup_result = setup_pipe_processes(node, data, &pid_1, &pid_2);
    if (setup_result == WAIT_NEXT_COMMAND)
        return (WAIT_NEXT_COMMAND);
    if (pid_1 > 0 && waitpid(pid_1, &status_1, 0) == -1)
        return (ft_perror("waitpid"));
    if (pid_2 > 0)
    {
        if (waitpid(pid_2, &status_2, 0) == -1)
            return (ft_perror("waitpid"));
        return (WEXITSTATUS(status_2));
    }
    return (WEXITSTATUS(status_1));
}
 
pid_t   execute_child(t_ast *node, t_ms_data *data, \
        int fd[2], int direction)
{
    pid_t   pid;
    int     status;
 
    pid = fork();
    if (pid == -1)
        ft_perror("fork");
    if (pid == 0)
    {
        if (direction == 0)
            dup2(fd[1], STDOUT_FILENO);
        else
            dup2(fd[0], STDIN_FILENO);
        close_fds(fd[0], fd[1]);
        status = execute_ast(node, data);
        exit(status);
    }
    return (pid);
}