You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: rdev.rs
    path of file: ./repos/rustybox/util_linux
    
    the code of the file until where you have to start completion: use libc;
use libc::printf;

/*
 * rdev - print device node associated with a filesystem
 *
 * Copyright (c) 2008 Nuovation System Designs, LLC
 *   Grant Erickson <gerickson@nuovations.com>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
//config:config RDEV
//config:	bool "rdev (1.8 kb)"
//config:	default y
//config:	help
//config:	Print 
    
pub unsafe fn rdev_main(mut _argc: libc::c_int, mut _argv: *mut *mut libc::c_char) -> libc::c_int {
  let mut root_device: *const libc::c_char =
    crate::libbb::find_root_device::find_block_device(b"/\x00" as *const u8 as *const libc::c_char);
  if !root_device.is_null() {
    printf(
      b"%s /\n\x00" as *const u8 as *const libc::c_char,
      root_device,
    );
    return 0;
  }
  return 1i32;
}