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microshell.c
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microshell.c
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#include <string.h>
#include <unistd.h>
#include <stdlib.h>
typedef struct s_cmd
{
int pipe[2];
int type[2];
int prev_pipe;
char **args;
} t_cmd;
int ft_strlen(char *str)
{
int len;
len = 0;
while (str[len])
len++;
return (len);
}
void ft_fatal(void)
{
write(2, "error: fatal\n", ft_strlen("error: fatal\n"));
exit(1);
}
int ft_list_end(t_cmd *list, int start, char **argv)
{
int end;
int len;
int semicolon_counter;
semicolon_counter = 0;
end = start;
while (argv[end] && strcmp(argv[end], "|") && strcmp(argv[end], ";"))
end++;
if (argv[end] && strcmp(argv[end], ";") == 0)
while (strcmp(argv[end + 1], ";") == 0)
{
end++;
semicolon_counter++;
}
len = end - start;
if (len > 0)
{
list->args = &argv[start];
list->type[0] = list->type[1];
if (argv[end] && strcmp(argv[end], "|") == 0)
list->type[1] = 1;
else
list->type[1] = 0;
argv[end] = NULL;
argv[end - semicolon_counter] = NULL;
list->prev_pipe = list->pipe[0];
}
return (end);
}
void ft_exec_cmd(t_cmd *list, char **env)
{
pid_t pid;
int ex;
if ((list->type[0] == 1 || list->type[1] == 1) && pipe(list->pipe) == -1)
ft_fatal();
if ((pid = fork()) == -1)
ft_fatal();
if (pid == 0)
{
if (list->type[0] == 1 && dup2(list->prev_pipe, 0) == -1)
ft_fatal();
if (list->type[1] == 1 && dup2(list->pipe[1], 1) == -1)
ft_fatal();
if ((ex = execve(list->args[0], list->args, env)) == -1)
{
write(2, "error: cannot execute ", ft_strlen("error: cannot execute "));
write(2, list->args[0], ft_strlen(list->args[0]));
write(2, "\n", 1);
}
exit(ex);
}
else
{
waitpid(pid, NULL, 0);
if (list->type[0] == 1 || list->type[1] == 1)
{
close(list->pipe[1]);
if (list->type[1] != 1)
close(list->pipe[0]);
}
if (list->type[0] == 1)
close(list->prev_pipe);
}
}
int main(int argc, char **argv, char **env)
{
t_cmd list;
int i;
int start;
i = 1;
while (i < argc)
{
start = i;
i = ft_list_end(&list, start, argv);
if (strcmp(argv[start], "cd") == 0)
{
if (i - start != 2)
write(2, "error: cd: bad arguments\n", ft_strlen("error: cd: bad arguments\n"));
else if (chdir(argv[start + 1]) == -1)
{
write(2, "error: cd: cannot change directory to ", ft_strlen("error: cd: cannot change directory to "));
write(2, argv[start + 1], ft_strlen(argv[start + 1]));
write(2, "\n", 1);
}
}
else
ft_exec_cmd(&list, env);
i++;
}
return (0);
}