Add nologin command

Cargo.toml

@@ -27,6 +27,7 @@ uudoc = []
 
 feat_common_core = [
   "login",
+  "nologin",
 ]
 
 [workspace.dependencies]
@@ -56,6 +57,7 @@ textwrap = { workspace = true }
 
 #
 login = { optional = true, version = "0.0.1", package = "uu_login", path = "src/uu/login" }
+nologin = { optional = true, version = "0.0.1", package = "uu_nologin", path = "src/uu/nologin" }
 
 [dev-dependencies]
 pretty_assertions = "1.4.0"

src/uu/nologin/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "uu_nologin"
+version = "0.0.1"
+edition = "2021"
+authors = ["uutils developers"]
+license = "MIT"
+description = "nologin ~ (uutils) Politely refuse a login"
+
+homepage = "https://github.com/uutils/login"
+repository = "https://github.com/uutils/login/tree/main/src/uu/nologin"
+keywords = ["acl", "uutils", "cross-platform", "cli", "utility"]
+categories = ["command-line-utilities"]
+
+[dependencies]
+uucore = { workspace = true }
+clap = { workspace = true }
+
+[lib]
+path = "src/nologin.rs"
+
+[[bin]]
+name = "nologin"
+path = "src/main.rs"
+

src/uu/nologin/nologin.md

@@ -0,0 +1,7 @@
+# nologin
+
+```
+nologin [options]
+```
+
+politely refuse a login

src/uu/nologin/src/main.rs

@@ -0,0 +1 @@
+uucore::bin!(uu_nologin);

src/uu/nologin/src/nologin.rs

@@ -0,0 +1,80 @@
+// This file is part of the uutils login package.
+//
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
+use clap::{crate_version, Arg, Command};
+use std::{ffi::OsString, io::Write};
+use uucore::{
+    error::{set_exit_code, UResult},
+    format_usage, help_about, help_usage,
+};
+
+const ABOUT: &str = help_about!("nologin.md");
+const USAGE: &str = help_usage!("nologin.md");
+
+#[uucore::main]
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
+    let mut command = uu_app();
+
+    // Mirror GNU options, always return `1`. In particular even the 'successful' cases of no-op,
+    // and the interrupted display of help and version should return `1`. Also, we return Ok in all
+    // paths to avoid the allocation of an error object, an operation that could, in theory, fail
+    // and unwind through the standard library allocation handling machinery.
+    set_exit_code(1);
+
+    let args: Vec<OsString> = args.collect();
+    if args.len() > 2 {
+        return Ok(());
+    }
+
+    if let Err(e) = command.try_get_matches_from_mut(args) {
+        let error = match e.kind() {
+            clap::error::ErrorKind::DisplayHelp => command.print_help(),
+            clap::error::ErrorKind::DisplayVersion => {
+                writeln!(std::io::stdout(), "{}", command.render_version())
+            }
+            clap::error::ErrorKind::UnknownArgument => {
+                if let Some((_, val)) = e.context().next() {
+                    writeln!(std::io::stdout(), "nologin: unrecognized option: {val}")?;
+                } else {
+                    writeln!(std::io::stdout(), "nologin: unrecognized option")?;
+                }
+                writeln!(
+                    std::io::stdout(),
+                    "Try 'nologin --help' for more information."
+                )
+            }
+            _ => Ok(()),
+        };
+
+        // Try to display this error.
+        if let Err(print_fail) = error {
+            // Completely ignore any error here, no more failover and we will fail in any case.
+            let _ = writeln!(std::io::stderr(), "{}: {}", uucore::util_name(), print_fail);
+        }
+    } else {
+        let _ = writeln!(
+            std::io::stdout(),
+            "This account is currently not available."
+        );
+    }
+
+    Ok(())
+}
+
+pub fn uu_app() -> Command {
+    Command::new(uucore::util_name())
+        .version(crate_version!())
+        .about(ABOUT)
+        .override_usage(format_usage(USAGE))
+        .infer_long_args(true)
+        .args_override_self(true)
+        .arg(
+            Arg::new("command")
+                .short('c')
+                .long("command")
+                .value_name("command")
+                .help("does nothing (for compatibility with su -c)"),
+        )
+}