Function nc::getdents

pub unsafe fn getdents(
    fd: i32,
    dirp: usize,
    count: size_t
) -> Result<ssize_t, Errno>

Get directory entries.

Example

let path = "/etc";
let ret = unsafe { nc::openat(nc::AT_FDCWD, path, nc::O_DIRECTORY, 0) };
assert!(ret.is_ok());
let fd = ret.unwrap();

const BUF_SIZE: usize = 4 * 1024;
loop {
    // TODO(Shaohua): Only allocate one buf block.
    let mut buf: Vec<u8> = vec![0; BUF_SIZE];
    let ret = unsafe { nc::getdents(fd, buf.as_mut_ptr() as usize, BUF_SIZE) };
    assert!(ret.is_ok());

    let buf_box = buf.into_boxed_slice();
    let buf_box_ptr = Box::into_raw(buf_box) as *mut u8 as usize;
    let nread = ret.unwrap() as usize;
    if nread == 0 {
        break;
    }

    let mut bpos: usize = 0;
    while bpos < nread {
        let d = (buf_box_ptr + bpos) as *mut nc::linux_dirent_t;
        let d_ref = unsafe { &(*d) };
        let mut name_vec: Vec<u8> = vec![];
        // TODO(Shaohua): Calculate string len of name.
        for i in 0..nc::PATH_MAX {
            let c = d_ref.d_name[i as usize];
            if c == 0 {
                break;
            }
            name_vec.push(c);
        }
        let _name = String::from_utf8(name_vec).unwrap();

        bpos += d_ref.d_reclen as usize;
    }
}

let ret = unsafe { nc::close(fd) };
assert!(ret.is_ok());