enumerage groups, Take Two

enum_grp2.rs

fn enumerate_groups() {
    let mut groupent: *mut libc::group;
    unsafe {
        setgrent();
        groupent = getgrent();
    }
    while groupent != ptr::null_mut() {
        let c_str: &CStr = unsafe { CStr::from_ptr((*groupent).gr_name) };
        println!("{}", c_str.to_str().unwrap());
        unsafe {
            if (*groupent).gr_mem != ptr::null_mut() {
                let member_ptr_arr: *mut *mut c_char = (*groupent).gr_mem;
                if member_ptr_arr == ptr::null_mut() {
                    continue;
                }
                for i in 0.. {
                    let member_ptr: *const c_char = *(member_ptr_arr.offset(i));
                    if member_ptr != ptr::null() {
                        let member: &CStr = CStr::from_ptr(member_ptr);
                        println!("  {}", member.to_str().unwrap());
                    } else {
                        break;
                    }
                }
            }
        }
        unsafe {
            groupent = getgrent();
        }
    }
    unsafe {
        endgrent();
    }
}