Enumerate groups, try 3 (working)

enum_grp3.rs

extern crate libc;
use libc::{endgrent, getgrent, setgrent, group};
use std::ffi::CStr;
use std::ptr;

struct Group {
    name: String,
    passwd: String,
    gid: libc::gid_t,
    members: Vec<String>,
}

fn load_group_db() -> Vec<Group> {
    let mut groups = Vec::new();

    unsafe {
        setgrent();  // Initialize the group entry stream
        let mut groupent = getgrent();  // Get the first group entry

        while !groupent.is_null() {
            let group = &*groupent;

            let name = CStr::from_ptr(group.gr_name).to_string_lossy().to_string();
            let passwd = CStr::from_ptr(group.gr_passwd).to_string_lossy().to_string();
            let gid = group.gr_gid;
            let mut members = Vec::new();

            if !group.gr_mem.is_null() {
                let mut member_ptr_arr = group.gr_mem;

                while !ptr::read_unaligned(member_ptr_arr).is_null() {
                    let member_ptr = ptr::read_unaligned(member_ptr_arr);
                    let member = CStr::from_ptr(member_ptr).to_string_lossy().to_string();
                    members.push(member);
                    member_ptr_arr = member_ptr_arr.add(1);
                }
            }

            groups.push(Group {
                name,
                passwd,
                gid,
                members,
            });

            groupent = getgrent();  // Move to the next group entry
        }

        endgrent();  // Close the group entry stream
    }

    groups
}

fn main() {
    let groups = load_group_db();
    for group in groups {
        println!("{}({})", group.gid, group.name);
        for member in &group.members {
            println!("\t{}", member);
        }
    }
}