exam_rank_04

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

#define F "error: fatal"
#define BAD "error: cd: bad arguments"
#define DIR "error: cd: cannot change directory to "
#define EXE "error: cannot execute "

typedef struct s_list
{
    char    **av;
    int     pipe_fd[2];
    int     prev_pipe;
    int     prev_type;
    int     type; } t_list;

int ft_strlen(char *s)
{
    int i = 0;

    while (s && s[i])
        i++;
    return (i);
}

void    msg(char *str, t_list *list, int k, int f)
{
    write(2, str, ft_strlen(str));
    if (k)
        write(2, list->av[0], ft_strlen(list->av[0]));
    write(2, "\n", 1);
    if (f)
        exit(1);
}

int init_list(t_list *list, char **av, int i)
{
    int end = i;

    while (av[end] && strcmp(av[end], "|") != 0 && strcmp(av[end], ";") != 0)
        end++;
    if ((end - i) > 0)
    {
        list->av = &av[i];
        list->prev_type = list->type;
        if (!av[end])
            list->type = 0;
        else if
            (strcmp(av[end], "|") == 0) list->type = 1;
        else
            list->type = 2;
        av[end] = NULL;
        list->prev_pipe = list->pipe_fd[0];
    }
    return (end);
}

void    fork_process(t_list *list, char **env)
{
    if (list->type == 1 && (dup2(list->pipe_fd[1], 1) < 0))
        msg(F, list, 0, 1);
    if (list->prev_type == 1 && (dup2(list->prev_pipe, 0) < 0))
        msg(F, list, 0, 1);
    if (execve(list->av[0], list->av, env) < 0)
        msg(EXE, list, 1, 1);
    //exit(0); Если не примет, то добавить
}

void    exe(t_list *list, char **env)
{
    pid_t   pid;

    if ((list->type == 1 || list->prev_type == 1) && pipe(list->pipe_fd))
        msg(F, list, 0, 1);
    if ((pid = fork()) < 0)
        msg(F, list, 0, 1);
    if (!pid)
        fork_process(list, env);
    else
    {
        waitpid(pid, NULL, 0);
        if (list->type == 1 || list->prev_type == 1)
            close(list->pipe_fd[1]);
        if (list->type != 1)
            close(list->pipe_fd[0]);
        if (list->prev_type == 1)
            close(list->prev_pipe);
    }
}

int main(int argc, char **argv, char **env)
{
    t_list  list;
    int     start, i = 0;

    while (i < argc && argv[++i])
    {
        start = i;
        i = init_list(&list, argv, i);
        if (strcmp(argv[start], "cd") == 0)
        {
            if (i - start != 2)
                msg(BAD, &list, 0, 0);
            else if (chdir(list.av[1]) < 0)
                msg(DIR, &list, 1, 0);
        }
        else if (i > start)
            exe(&list, env);
    }
    return (0);
}