List the screened hosts from the config

Building a Firewall needs a runtime, which an installer has no use for.

core/Cargo.lock

@@ -45,6 +45,56 @@ dependencies = [
  "alloc-no-stdlib",
 ]
 
+[[package]]
+name = "anstream"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "824a212faf96e9acacdbd09febd34438f8f711fb84e09a8916013cd7815ca28d"
+dependencies = [
+ "anstyle",
+ "anstyle-parse",
+ "anstyle-query",
+ "anstyle-wincon",
+ "colorchoice",
+ "is_terminal_polyfill",
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle"
+version = "1.0.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "940b3a0ca603d1eade50a4846a2afffd5ef57a9feac2c0e2ec2e14f9ead76000"
+
+[[package]]
+name = "anstyle-parse"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52ce7f38b242319f7cabaa6813055467063ecdc9d355bbb4ce0c68908cd8130e"
+dependencies = [
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle-query"
+version = "1.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
+dependencies = [
+ "windows-sys 0.61.2",
+]
+
+[[package]]
+name = "anstyle-wincon"
+version = "3.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
+dependencies = [
+ "anstyle",
+ "once_cell_polyfill",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "anyhow"
 version = "1.0.104"
@@ -210,12 +260,6 @@ dependencies = [
  "cfg_aliases",
 ]
 
-[[package]]
-name = "bpaf"
-version = "0.9.28"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "597e81e56404b7a3e26ef7b449f82a4b7a661ae76c3cac692b42d6bad06a0fbe"
-
 [[package]]
 name = "brotli"
 version = "8.0.4"
@@ -313,6 +357,33 @@ dependencies = [
  "libloading",
 ]
 
+[[package]]
+name = "clap"
+version = "4.6.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aa8876b300ab35ba921adea3dfd70157a46249b33f95c9084ae5709785478946"
+dependencies = [
+ "clap_builder",
+]
+
+[[package]]
+name = "clap_builder"
+version = "4.6.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0797fb7aeb1406c84efac526901f7ec3ead2124f946b494e72879d4b54704d"
+dependencies = [
+ "anstream",
+ "anstyle",
+ "clap_lex",
+ "strsim",
+]
+
+[[package]]
+name = "clap_lex"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1c133bc6a41be0d194c306b5506d15e6feeea7b1d6604bd3f8310dfb2ca96486"
+
 [[package]]
 name = "cmake"
 version = "0.1.58"
@@ -322,6 +393,12 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "colorchoice"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
+
 [[package]]
 name = "combine"
 version = "4.6.8"
@@ -1100,6 +1177,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "is_terminal_polyfill"
+version = "1.70.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
+
 [[package]]
 name = "itertools"
 version = "0.13.0"
@@ -1562,6 +1645,12 @@ version = "1.21.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9f7c3e4beb33f85d45ae3e3a1792185706c8e16d043238c593331cc7cd313b50"
 
+[[package]]
+name = "once_cell_polyfill"
+version = "1.70.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
+
 [[package]]
 name = "openssl-macros"
 version = "0.1.1"
@@ -3004,7 +3093,7 @@ checksum = "6ce2be8dc25455e1f91df71bfa12ad37d7af1092ae736f3a6cd0e37bc7810596"
 name = "strix-firewall"
 version = "0.1.0"
 dependencies = [
- "bpaf",
+ "clap",
  "core-foundation",
  "directories",
  "percent-encoding",
@@ -3024,6 +3113,12 @@ dependencies = [
  "which",
 ]
 
+[[package]]
+name = "strsim"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
+
 [[package]]
 name = "subtle"
 version = "2.6.1"
@@ -3433,6 +3528,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6c140620e7ffbb22c2dee59cafe6084a59b5ffc27a8859a5f0d494b5d52b6be"
 
+[[package]]
+name = "utf8parse"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
+
 [[package]]
 name = "uuid"
 version = "1.26.1"

core/Cargo.toml

@@ -53,7 +53,7 @@ name = "managers"
 path = "tests/managers.rs"
 
 [dependencies]
-bpaf = "0.9.28"
+clap = "4.6.6"
 directories = "6.0.0"
 percent-encoding = "2.3.2"
 rama = { version = "0.4.0", features = ["boring", "http-full", "ring", "rustls"] }

core/src/aliasing/forward.rs

@@ -1,15 +1,20 @@
 use crate::http::{blocked, https_url, text};
 use crate::{policies, telemetry};
 use crate::{Firewall, FirewallConfig};
+use rama::dns::client::DnsConnectorLayer;
 use rama::http::body::util::BodyExt;
 use rama::http::client::EasyHttpWebClient;
 use rama::http::header::CONTENT_LENGTH;
 use rama::http::layer::decompression::DecompressionLayer;
 use rama::http::layer::remove_header::{RemoveRequestHeaderLayer, RemoveResponseHeaderLayer};
+use rama::http::layer::upgrade::{EagerHttpProxyConnector, UpgradeLayer};
 use rama::http::server::HttpServer;
 use rama::http::{Body, Method, Request, Response};
+use rama::matcher::match_fn;
+use rama::net::proxy::IoForwardService;
 use rama::rt::Executor;
 use rama::service::service_fn;
+use rama::tcp::client::service::TcpConnector;
 use rama::tcp::server::TcpListener;
 use rama::{Layer, Service};
 use std::convert::Infallible;
@@ -31,8 +36,26 @@ pub fn spawn(port: u16, config: FirewallConfig) -> std::io::Result<u16> {
                 Ok(listener) => listener,
                 Err(e) => return error!(error = %e, "forward proxy could not take over the socket"),
             };
+            // Tunnels skip screening, so a registry's CONNECT falls through to `handle`, which refuses it.
+            let hosts = firewall.hosts();
+            let tunnel = UpgradeLayer::new(
+                exec.clone(),
+                match_fn(move |req: &Request| {
+                    let host = req.uri().host().map(|host| host.to_str());
+                    req.method() == Method::CONNECT
+                        && host.is_some_and(|host| !hosts.contains(&host.as_ref()))
+                }),
+                EagerHttpProxyConnector::new(
+                    DnsConnectorLayer::new().into_layer(TcpConnector::new()),
+                    IoForwardService::default(),
+                ),
+            );
             let server = HttpServer::auto(exec).service(
-                (RemoveResponseHeaderLayer::hop_by_hop(), RemoveRequestHeaderLayer::hop_by_hop())
+                (
+                    RemoveResponseHeaderLayer::hop_by_hop(),
+                    RemoveRequestHeaderLayer::hop_by_hop(),
+                    tunnel,
+                )
                     .into_layer(service_fn(move |req: Request| {
                         let firewall = Arc::clone(&firewall);
                         async move { handle(req, &firewall).await }
@@ -66,16 +89,12 @@ async fn handle(req: Request, firewall: &Firewall) -> Result<Response, Infallibl
     }
 
     info!(method = %req.method(), %url, "forwarding");
-    // Only an HTTPS registry was downgraded to reach us, so only it is upgraded back and rewritten.
-    let tls = firewall.is_https_url(&url);
-    let index = tls && firewall.is_index_url(&url);
+    let index = firewall.is_index_url(&url);
     let (mut parts, body) = req.into_parts();
-    if tls {
-        let Ok(uri) = url.parse() else {
-            return Ok(text(400, "firewall: expected an absolute URL\n"));
-        };
-        parts.uri = uri;
-    }
+    let Ok(uri) = url.parse() else {
+        return Ok(text(400, "firewall: expected an absolute URL\n"));
+    };
+    parts.uri = uri;
 
     let client = DecompressionLayer::new().into_layer(EasyHttpWebClient::default());
     let response = match client.serve(Request::from_parts(parts, body)).await {

core/src/aliasing/managers/mod.rs

@@ -41,8 +41,10 @@ pub struct Manager {
 pub static MANAGERS: &[&Manager] =
     &[&NPM, &PIP, &PIP3, &CARGO, &GO, &GEM, &UV, &PDM, &PIPENV, &PNPM, &BUN];
 
-pub fn variables(proxy: &str, manager: &Manager) -> Vec<(String, String)> {
-    manager.env.iter().map(|(key, value)| (key.to_string(), expand(value, proxy))).collect()
+/// Every manager's variables, so whichever the command starts is pointed at the firewall.
+pub fn variables(proxy: &str) -> Vec<(String, String)> {
+    let env = MANAGERS.iter().flat_map(|manager| manager.env);
+    env.map(|(key, value)| (key.to_string(), expand(value, proxy))).collect()
 }
 
 pub fn arguments(proxy: &str, manager: &Manager, typed: &[String]) -> Vec<String> {

core/src/aliasing/managers/pipenv.rs

@@ -9,6 +9,8 @@ pub static PIPENV: Manager = Manager {
         ("http_proxy", PROXY),
         ("https_proxy", PROXY),
         ("PIPENV_PYPI_MIRROR", PYPI_SIMPLE),
+        // pipenv installs through pip, which skips a plaintext index on a host it doesn't trust.
+        ("PIP_TRUSTED_HOST", "pypi.org files.pythonhosted.org"),
     ],
     args: &[],
 };

core/src/aliasing/mod.rs

@@ -9,30 +9,37 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 
 pub struct Invocation {
-    pub manager: &'static Manager,
+    pub program: String,
     pub args: Vec<String>,
 }
 
 impl Invocation {
-    pub fn new(manager: &'static Manager, args: Vec<String>) -> Self {
-        Invocation { manager, args }
+    pub fn new(program: String, args: Vec<String>) -> Self {
+        Invocation { program, args }
+    }
+
+    /// What the program is run with: the typed arguments plus any its manager needs.
+    pub fn arguments(&self, proxy: &str) -> Vec<String> {
+        let mut args = self.args.clone();
+        let Some(manager) = MANAGERS.iter().find(|manager| manager.command == self.program) else {
+            return args;
+        };
+        let ours = managers::arguments(proxy, manager, &args);
+        // Anything after `--` belongs to another program, so ours go before it.
+        let at = args.iter().position(|arg| arg == "--").unwrap_or(args.len());
+        args.splice(at..at, ours);
+        args
     }
 }
 
 pub fn run(port: u16, invocation: &Invocation, dir: Option<&Path>) -> std::io::Result<i32> {
     let proxy = crate::local_url(port, "");
-    let mut args = invocation.args.clone();
-    let ours = managers::arguments(&proxy, invocation.manager, &args);
-    // Anything after `--` belongs to another program, so ours go before it.
-    let at = args.iter().position(|arg| arg == "--").unwrap_or(args.len());
-    args.splice(at..at, ours);
-
-    let mut command = Command::new(resolve(invocation.manager.command)?);
-    command.args(args);
+    let mut command = Command::new(resolve(&invocation.program)?);
+    command.args(invocation.arguments(&proxy));
     if let Some(dir) = dir {
         command.current_dir(dir);
     }
-    for (key, value) in managers::variables(&proxy, invocation.manager) {
+    for (key, value) in managers::variables(&proxy) {
         command.env(key, value);
     }
     Ok(command.status()?.code().unwrap_or(1))

core/src/config/mod.rs

@@ -80,6 +80,18 @@ impl FirewallConfig {
     pub fn local_url(&self, path: &str) -> String {
         crate::local_url(self.port, path)
     }
+
+    /// Without building a `Firewall`, which needs a runtime.
+    pub fn hosts(&self) -> Vec<&'static str> {
+        let mut hosts: Vec<&'static str> = Vec::new();
+        for registry in &self.registries {
+            let host = registry.host();
+            if !hosts.contains(&host) {
+                hosts.push(host);
+            }
+        }
+        hosts
+    }
 }
 
 pub fn path() -> Option<PathBuf> {

core/src/firewall.rs

@@ -40,19 +40,7 @@ impl Firewall {
     }
 
     pub fn hosts(&self) -> Vec<&'static str> {
-        let mut hosts: Vec<&'static str> = Vec::new();
-        for registry in &self.config.registries {
-            let host = registry.host();
-            if !hosts.contains(&host) {
-                hosts.push(host);
-            }
-        }
-        hosts
-    }
-
-    pub fn is_https_url(&self, url: &str) -> bool {
-        let host = host_of(url);
-        self.config.registries.iter().any(|r| r.upstream.starts_with("https://") && r.host() == host)
+        self.config.hosts()
     }
 
     pub fn is_index_url(&self, url: &str) -> bool {

core/src/main.rs

@@ -1,64 +1,52 @@
-use bpaf::{any, choice, pure, OptionParser, Parser};
-use firewall::aliasing::{self, Invocation, Manager, MANAGERS};
+use clap::{Arg, Command};
+use firewall::aliasing::{self, Invocation, MANAGERS};
 use firewall::{config, proxy, telemetry, FirewallConfig};
 use std::io::ErrorKind;
 use std::path::Path;
 use std::process::exit;
 use tracing::{error, info};
 
-enum SubCommand {
-    Serve,
-    Run(Invocation),
-}
-
 fn main() {
-    match options().run() {
-        SubCommand::Serve => {
-            firewall::init_logging("info");
-            serve()
-        }
-        SubCommand::Run(invocation) => {
-            firewall::init_logging("warn");
-            run(invocation)
-        }
+    let matches = options().get_matches();
+    if matches.subcommand_matches("serve").is_some() {
+        firewall::init_logging("info");
+        serve()
     }
+    let mut command = matches.get_many::<String>("COMMAND").unwrap().cloned();
+    let program = command.next().unwrap();
+    firewall::init_logging("warn");
+    run(Invocation::new(program, command.collect()))
 }
 
-fn options() -> OptionParser<SubCommand> {
+fn options() -> Command {
     let program = program_name();
+    let managers: Vec<_> = MANAGERS.iter().map(|manager| manager.command).collect();
     let footer = format!(
-        "Run a package manager through {program} to screen what it installs:\n   \
-         {program} npm install left-pad\n \n \
-         Alias it to screen every install without changing how you type:\n   \
-         alias npm='{program} npm'"
+        "Run a command through {program} to screen what it installs:\n  \
+         {program} npm install left-pad\n\n\
+         Alias it to screen every install without changing how you type:\n  \
+         {}\n\n\
+         Supported package managers: {}",
+        alias(&program),
+        managers.join(", ")
     );
-    let serve = pure(())
-        .map(|()| SubCommand::Serve)
-        .to_options()
-        .descr("Serve a local registry for package managers configured to use it")
-        .command("serve");
-
-    let mut commands: Vec<_> = MANAGERS
-        .iter()
-        .map(|manager| package(manager, &program).boxed())
-        .collect();
-    commands.push(serve.boxed());
-    choice(commands)
-        .to_options()
-        .descr("Screens package downloads before they reach your machine")
-        .footer(Box::leak(footer.into_boxed_str()) as &str)
-        .fallback_to_usage()
-}
-
-fn package(manager: &'static Manager, program: &str) -> impl Parser<SubCommand> {
-    let name = manager.command;
-    let descr = format!("Run {name} with downloads screened: {program} {name} ARGS...");
-    any::<String, String, _>("ARGS", Some)
-        .many()
-        .map(move |args| SubCommand::Run(Invocation::new(manager, args)))
-        .to_options()
-        .descr(Box::leak(descr.into_boxed_str()) as &str)
-        .command(name)
+    Command::new("firewall")
+        .bin_name(&program)
+        .about("Screens package downloads before they reach your machine")
+        .after_help(footer)
+        .arg_required_else_help(true)
+        .args_conflicts_with_subcommands(true)
+        .subcommand(
+            Command::new("serve")
+                .about("Serve a local registry for package managers configured to use it"),
+        )
+        .arg(
+            Arg::new("COMMAND")
+                .help("A command to run with its package downloads screened")
+                .num_args(1..)
+                .trailing_var_arg(true)
+                .allow_hyphen_values(true),
+        )
 }
 
 fn serve() -> ! {
@@ -82,7 +70,7 @@ fn serve() -> ! {
 }
 
 fn run(invocation: Invocation) -> ! {
-    let command = invocation.manager.command;
+    let command = &invocation.program;
     let port = match aliasing::spawn(0, load()) {
         Ok(port) => port,
         Err(e) => fail("spawn", &format!("could not start the firewall: {e}")),
@@ -105,12 +93,32 @@ fn print_setup(config: &FirewallConfig) {
     let base = config.local_url("");
     println!("Firewall listening on {base}\n");
     println!("Point your package managers at it:");
-    println!("  npm    npm_config_registry={base}/npm/");
-    println!("  pip    PIP_INDEX_URL={base}/pypi/simple/");
+    println!("  npm    {}", variable("npm_config_registry", &format!("{base}/npm/")));
+    println!("  pip    {}", variable("PIP_INDEX_URL", &format!("{base}/pypi/simple/")));
     println!("  cargo  [source.crates-io] replace-with = \"firewall\"");
     println!("         [source.firewall] registry = \"sparse+{base}/cargo/index/\"\n");
 }
 
+fn alias(program: &str) -> String {
+    if cfg!(windows) {
+        // Set-Alias cannot carry arguments, so a function stands in.
+        format!(
+            "PowerShell:  function npm {{ {program} npm @args }}\n  \
+             cmd:         doskey npm={program} npm $*"
+        )
+    } else {
+        format!("alias npm='{program} npm'")
+    }
+}
+
+fn variable(key: &str, value: &str) -> String {
+    if cfg!(windows) {
+        format!("$env:{key} = \"{value}\"")
+    } else {
+        format!("{key}={value}")
+    }
+}
+
 fn load() -> FirewallConfig {
     match FirewallConfig::load() {
         Ok(config) => config,
@@ -127,7 +135,9 @@ fn fail(kind: &'static str, message: &str) -> ! {
 
 fn program_name() -> String {
     let arg = std::env::args_os().next().unwrap_or_default();
-    match Path::new(&arg).file_name() {
+    // Without `.exe` on Windows, which is how it is typed.
+    let path = Path::new(&arg);
+    match if cfg!(windows) { path.file_stem() } else { path.file_name() } {
         Some(name) => name.to_string_lossy().into_owned(),
         None => "firewall".into(),
     }

core/tests/forward.rs

@@ -1,9 +1,7 @@
 use firewall::aliasing::forward::downgrade;
 use firewall::http::https_url;
-use firewall::{aliasing, Firewall, FirewallConfig};
+use firewall::Firewall;
 use rama::http::{Body, Request};
-use std::io::{Read, Write};
-use std::net::{TcpListener, TcpStream};
 
 fn request(target: &str, host: Option<&str>) -> Request {
     let mut builder = Request::builder().method("GET").uri(target);
@@ -37,25 +35,6 @@ fn requests_always_go_out_over_tls() {
     assert_eq!(https_url(&request("/six", None)), None);
 }
 
-#[test]
-fn a_plain_http_upstream_is_not_upgraded() {
-    let upstream = TcpListener::bind("127.0.0.1:0").expect("bind");
-    let addr = upstream.local_addr().expect("address");
-    std::thread::spawn(move || {
-        let (mut stream, _) = upstream.accept().expect("accept");
-        let _ = stream.read(&mut [0; 4096]);
-        let _ = stream.write_all(b"HTTP/1.1 200 OK\r\nContent-Length: 2\r\n\r\nok");
-    });
-
-    let port = aliasing::spawn(0, FirewallConfig::default()).expect("spawn");
-    let mut proxy = TcpStream::connect(("127.0.0.1", port)).expect("connect");
-    let request = format!("GET http://{addr}/x HTTP/1.1\r\nHost: {addr}\r\nConnection: close\r\n\r\n");
-    proxy.write_all(request.as_bytes()).expect("write");
-    let mut response = String::new();
-    proxy.read_to_string(&mut response).expect("read");
-    assert!(response.starts_with("HTTP/1.1 200") && response.ends_with("ok"), "{response}");
-}
-
 #[tokio::test]
 async fn downgrade_touches_known_hosts_in_text_only() {
     let text = b"https://pypi.org/x https://example.com/y".to_vec();

core/tests/managers.rs

@@ -1,10 +1,19 @@
 use firewall::aliasing::managers::*;
+use firewall::aliasing::Invocation;
 use firewall::Firewall;
 
+#[test]
+fn arguments_after_a_double_dash_reach_the_program() {
+    let typed = ["run", "--", "--release"].map(String::from).to_vec();
+    let args = Invocation::new("cargo".into(), typed).arguments("http://127.0.0.1:9000");
+    assert_eq!(args.first().map(String::as_str), Some("run"));
+    assert_eq!(args[args.len() - 2..], ["--", "--release"]);
+}
+
 #[test]
 fn recipes_expand_into_the_environment() {
     let var = |name: &str, value: &str| (name.to_string(), value.to_string());
-    let npm = variables("http://127.0.0.1:9000", &NPM);
+    let npm = variables("http://127.0.0.1:9000");
     assert!(npm.contains(&var("npm_config_proxy", "http://127.0.0.1:9000")));
     assert!(npm.contains(&var("npm_config_registry", "http://registry.npmjs.org/")));
     let gem = arguments("http://127.0.0.1:9000", &GEM, &["install".to_string()]);
@@ -12,6 +21,17 @@ fn recipes_expand_into_the_environment() {
     assert!(arguments("http://127.0.0.1:9000", &GEM, &["sources".to_string()]).is_empty());
 }
 
+#[test]
+fn no_two_managers_set_a_variable_differently() {
+    let mut seen = std::collections::HashMap::new();
+    for manager in MANAGERS {
+        for (key, value) in manager.env {
+            let first = *seen.entry(key).or_insert(value);
+            assert_eq!(first, value, "{} sets {key} differently", manager.command);
+        }
+    }
+}
+
 #[tokio::test]
 async fn every_overridden_registry_is_known() {
     let hosts = Firewall::default().hosts();

core/tests/proxy-test/probe.rs

@@ -36,7 +36,7 @@ pub fn all(port: u16) -> Vec<(&'static str, Outcome)> {
 fn run(probe: &Probe, port: u16) -> Outcome {
     let args = probe.args.iter().map(|arg| arg.to_string()).collect();
     let dir = probe.setup.and_then(|prepare| prepare());
-    match aliasing::run(port, &Invocation::new(probe.manager, args), dir.as_deref()) {
+    match aliasing::run(port, &Invocation::new(probe.manager.command.into(), args), dir.as_deref()) {
         Ok(0) => Outcome::Ok,
         Ok(_) => Outcome::Failed,
         Err(e) if e.kind() == std::io::ErrorKind::NotFound => Outcome::Absent,