armybox 0.3.0

A memory-safe #[no_std] BusyBox/Toybox clone in Rust - 299 Unix utilities in ~500KB
Documentation 
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//! host - DNS lookup utility
//!
//! Perform DNS lookups.

use crate::io;
use crate::sys;
use super::get_arg;

/// host - DNS lookup utility
///
/// # Synopsis
/// ```text
/// host HOSTNAME
/// ```
///
/// # Description
/// Look up the IP address of a hostname using DNS.
///
/// # Exit Status
/// - 0: Success
/// - 1: Host not found or error
pub fn host(argc: i32, argv: *const *const u8) -> i32 {
    if argc < 2 {
        io::write_str(2, b"host: missing hostname\n");
        return 1;
    }

    let hostname = unsafe { get_arg(argv, 1).unwrap() };
    let mut host_buf = [0u8; 256];
    host_buf[..hostname.len()].copy_from_slice(hostname);

    let mut hints: libc::addrinfo = unsafe { core::mem::zeroed() };
    hints.ai_family = libc::AF_UNSPEC;
    let mut res: *mut libc::addrinfo = core::ptr::null_mut();

    if unsafe { libc::getaddrinfo(host_buf.as_ptr() as *const i8, core::ptr::null(), &hints, &mut res) } != 0 {
        io::write_str(2, b"host: ");
        io::write_all(2, hostname);
        io::write_str(2, b" not found\n");
        return 1;
    }

    io::write_all(1, hostname);
    io::write_str(1, b" has address ");

    let mut current = res;
    while !current.is_null() {
        let info = unsafe { &*current };
        if info.ai_family == libc::AF_INET {
            let addr = unsafe { &*(info.ai_addr as *const libc::sockaddr_in) };
            let ip = addr.sin_addr.s_addr.to_be();
            let mut num_buf = [0u8; 20];
            io::write_all(1, sys::format_u64(((ip >> 24) & 0xff) as u64, &mut num_buf));
            io::write_str(1, b".");
            io::write_all(1, sys::format_u64(((ip >> 16) & 0xff) as u64, &mut num_buf));
            io::write_str(1, b".");
            io::write_all(1, sys::format_u64(((ip >> 8) & 0xff) as u64, &mut num_buf));
            io::write_str(1, b".");
            io::write_all(1, sys::format_u64((ip & 0xff) as u64, &mut num_buf));
            io::write_str(1, b"\n");
            break;
        }
        current = info.ai_next;
    }

    unsafe { libc::freeaddrinfo(res) };
    0
}

#[cfg(test)]
mod tests {
    extern crate std;
    use std::process::Command;
    use std::path::PathBuf;

    fn get_armybox_path() -> PathBuf {
        if let Ok(path) = std::env::var("ARMYBOX_PATH") {
            return PathBuf::from(path);
        }
        let manifest_dir = std::env::var("CARGO_MANIFEST_DIR")
            .map(PathBuf::from)
            .unwrap_or_else(|_| std::env::current_dir().unwrap());
        let release = manifest_dir.join("target/release/armybox");
        if release.exists() { return release; }
        manifest_dir.join("target/debug/armybox")
    }

    #[test]
    fn test_host_no_args() {
        let armybox = get_armybox_path();
        if !armybox.exists() { return; }

        let output = Command::new(&armybox)
            .args(["host"])
            .output()
            .unwrap();

        assert_eq!(output.status.code(), Some(1));
        let stderr = std::string::String::from_utf8_lossy(&output.stderr);
        assert!(stderr.contains("missing"));
    }

    #[test]
    fn test_host_localhost() {
        let armybox = get_armybox_path();
        if !armybox.exists() { return; }

        let output = Command::new(&armybox)
            .args(["host", "localhost"])
            .output()
            .unwrap();

        assert_eq!(output.status.code(), Some(0));
        let stdout = std::string::String::from_utf8_lossy(&output.stdout);
        assert!(stdout.contains("127.0.0.1") || stdout.contains("address"));
    }
}