[pipe] ftp не хочет общатся через два пайпа

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

int main(int argc, char *const argv[])
{
	int in[2], out[2], len;
	char buf[80];

	if (pipe(in) != 0 || pipe(out) != 0 )
	{
		perror("pipe");
		return EXIT_FAILURE;
	}

	if (fork() == 0)
	{
		close(0);//
		close(1);

		dup(in[0]);//
		dup(out[1]);

		close(in[1]);
		close(out[0]);

		execlp("ftp", "ftp", "-n", "ftp.mozilla.org", (char *)NULL);
		//execlp("pwd", (char *)NULL);
		perror("execlp");
		return EXIT_FAILURE;
	}

	close(in[0]);
	close(out[1]);

	setvbuf(stdout, NULL, _IONBF, 0);
	while (len = read(out[0], (void *)buf, sizeof(buf)-1), len > 0)
	{
		buf[len] = 0;
		printf("%s", buf);
	}

	close(in[0]);
	close(out[1]);
	return EXIT_SUCCESS;
}

gcc main.c && ./a.exe