cat: do not connect to unix domain socket and instead return an error

src/uu/cat/locales/en-US.ftl

@@ -19,3 +19,4 @@ cat-error-unknown-filetype = unknown filetype: { $ft_debug }
 cat-error-is-directory = Is a directory
 cat-error-input-file-is-output-file = input file is output file
 cat-error-too-many-symbolic-links = Too many levels of symbolic links
+cat-error-no-such-device-or-address = No such device or address

src/uu/cat/locales/fr-FR.ftl

@@ -19,3 +19,4 @@ cat-error-unknown-filetype = type de fichier inconnu : { $ft_debug }
 cat-error-is-directory = Est un répertoire
 cat-error-input-file-is-output-file = le fichier d'entrée est le fichier de sortie
 cat-error-too-many-symbolic-links = Trop de niveaux de liens symboliques
+cat-error-no-such-device-or-address = Aucun appareil ou adresse de ce type

src/uu/cat/src/cat.rs

@@ -13,15 +13,10 @@ use memchr::memchr2;
 use std::ffi::OsString;
 use std::fs::{File, metadata};
 use std::io::{self, BufWriter, ErrorKind, IsTerminal, Read, Write};
-/// Unix domain socket support
-#[cfg(unix)]
-use std::net::Shutdown;
 #[cfg(unix)]
 use std::os::fd::AsFd;
 #[cfg(unix)]
 use std::os::unix::fs::FileTypeExt;
-#[cfg(unix)]
-use std::os::unix::net::UnixStream;
 use thiserror::Error;
 use uucore::display::Quotable;
 use uucore::error::UResult;
@@ -103,6 +98,9 @@ enum CatError {
     },
     #[error("{}", translate!("cat-error-is-directory"))]
     IsDirectory,
+    #[cfg(unix)]
+    #[error("{}", translate!("cat-error-no-such-device-or-address"))]
+    NoSuchDeviceOrAddress,
     #[error("{}", translate!("cat-error-input-file-is-output-file"))]
     OutputIsInput,
     #[error("{}", translate!("cat-error-too-many-symbolic-links"))]
@@ -395,15 +393,7 @@ fn cat_path(path: &OsString, options: &OutputOptions, state: &mut OutputState) -
         }
         InputType::Directory => Err(CatError::IsDirectory),
         #[cfg(unix)]
-        InputType::Socket => {
-            let socket = UnixStream::connect(path)?;
-            socket.shutdown(Shutdown::Write)?;
-            let mut handle = InputHandle {
-                reader: socket,
-                is_interactive: false,
-            };
-            cat_handle(&mut handle, options, state)
-        }
+        InputType::Socket => Err(CatError::NoSuchDeviceOrAddress),
         _ => {
             let file = File::open(path)?;
             if is_unsafe_overwrite(&file, &io::stdout()) {

tests/by-util/test_cat.rs

@@ -576,37 +576,17 @@ fn test_write_fast_fallthrough_uses_flush() {
 
 #[test]
 #[cfg(unix)]
-#[ignore = ""]
 fn test_domain_socket() {
-    use std::io::prelude::*;
     use std::os::unix::net::UnixListener;
-    use std::sync::{Arc, Barrier};
-    use std::thread;
-
-    let dir = tempfile::Builder::new()
-        .prefix("unix_socket")
-        .tempdir()
-        .expect("failed to create dir");
-    let socket_path = dir.path().join("sock");
-    let listener = UnixListener::bind(&socket_path).expect("failed to create socket");
-
-    // use a barrier to ensure we don't run cat before the listener is setup
-    let barrier = Arc::new(Barrier::new(2));
-    let barrier2 = Arc::clone(&barrier);
-
-    let thread = thread::spawn(move || {
-        let mut stream = listener.accept().expect("failed to accept connection").0;
-        barrier2.wait();
-        stream
-            .write_all(b"a\tb")
-            .expect("failed to write test data");
-    });
 
-    let child = new_ucmd!().args(&[socket_path]).run_no_wait();
-    barrier.wait();
-    child.wait().unwrap().stdout_is("a\tb");
+    let s = TestScenario::new(util_name!());
+    let socket_path = s.fixtures.plus("sock");
+    let _ = UnixListener::bind(&socket_path).expect("failed to create socket");
 
-    thread.join().unwrap();
+    s.ucmd()
+        .args(&[socket_path])
+        .fails()
+        .stderr_contains("No such device or address");
 }
 
 #[test]