hostname: use dns-lookup crate to get the network address(es) of the host

- on OpenBSD and FreeBSD, unable to get the network address(es) of the host with DNS request for
  hostname + ":1"
- use dns-lookup crate for this request with lookup_host function

Signed-off-by: Laurent Cheylus <foxy@free.fr>

Cargo.lock

@@ -2814,6 +2814,7 @@ name = "uu_hostname"
 version = "0.0.27"
 dependencies = [
  "clap",
+ "dns-lookup",
  "hostname",
  "uucore",
  "windows-sys 0.48.0",

Cargo.toml

@@ -283,6 +283,7 @@ compare = "0.1.0"
 coz = { version = "0.1.3" }
 crossterm = ">=0.27.0"
 ctrlc = { version = "3.4.4", features = ["termination"] }
+dns-lookup = { version = "2.0.4" }
 exacl = "0.12.0"
 file_diff = "1.0.0"
 filetime = "0.2.23"

src/uu/hostname/Cargo.toml

@@ -21,6 +21,9 @@ clap = { workspace = true }
 hostname = { workspace = true, features = ["set"] }
 uucore = { workspace = true, features = ["wide"] }
 
+[target.'cfg(any(target_os = "freebsd", target_os = "openbsd"))'.dependencies]
+dns-lookup = { workspace = true }
+
 [target.'cfg(target_os = "windows")'.dependencies]
 windows-sys = { workspace = true, features = [
   "Win32_Networking_WinSock",

src/uu/hostname/src/hostname.rs

@@ -3,8 +3,9 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-// spell-checker:ignore (ToDO) MAKEWORD addrs hashset
+// spell-checker:ignore hashset Addrs addrs
 
+#[cfg(not(any(target_os = "freebsd", target_os = "openbsd")))]
 use std::net::ToSocketAddrs;
 use std::str;
 use std::{collections::hash_set::HashSet, ffi::OsString};
@@ -12,6 +13,9 @@ use std::{collections::hash_set::HashSet, ffi::OsString};
 use clap::builder::ValueParser;
 use clap::{crate_version, Arg, ArgAction, ArgMatches, Command};
 
+#[cfg(any(target_os = "freebsd", target_os = "openbsd"))]
+use dns_lookup::lookup_host;
+
 use uucore::{
     error::{FromIo, UResult},
     format_usage, help_about, help_usage,
@@ -121,13 +125,25 @@ fn display_hostname(matches: &ArgMatches) -> UResult<()> {
         .into_owned();
 
     if matches.get_flag(OPT_IP_ADDRESS) {
-        // XXX: to_socket_addrs needs hostname:port so append a dummy port and remove it later.
-        // This was originally supposed to use std::net::lookup_host, but that seems to be
-        // deprecated.  Perhaps we should use the dns-lookup crate?
-        let hostname = hostname + ":1";
-        let addresses = hostname
-            .to_socket_addrs()
-            .map_err_context(|| "failed to resolve socket addresses".to_owned())?;
+        let addresses;
+
+        #[cfg(not(any(target_os = "freebsd", target_os = "openbsd")))]
+        {
+            let hostname = hostname + ":1";
+            let addrs = hostname
+                .to_socket_addrs()
+                .map_err_context(|| "failed to resolve socket addresses".to_owned())?;
+            addresses = addrs;
+        }
+
+        // DNS reverse lookup via "hostname:1" does not work on FreeBSD and OpenBSD
+        // use dns-lookup crate instead
+        #[cfg(any(target_os = "freebsd", target_os = "openbsd"))]
+        {
+            let addrs: Vec<std::net::IpAddr> = lookup_host(hostname.as_str()).unwrap();
+            addresses = addrs;
+        }
+
         let mut hashset = HashSet::new();
         let mut output = String::new();
         for addr in addresses {