Component

cat

Description

uutils cat treats files whose paths are Unix domain sockets as clients, connecting to them via connect() and reading data; GNU cat only performs open() and does not actively connect to such sockets (usually returning an error directly).

Test / Reproduction Steps

``
import socket
import os

sock_path = "/tmp/tmp.sock"

if os.path.exists(sock_path):
os.remove(sock_path)

with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as server:
server.bind(sock_path)
server.listen(1)
print(f"Listening on {sock_path}...")

while True:
    conn, _ = server.accept()
    try:
        conn.sendall(b"Hello Sock!\n")
    finally:
        conn.close()

```bash
$ cat /tmp/tmp.sock                                                 
cat: /tmp/tmp.sock: No such device or address
$ ./target/release/coreutils cat /tmp/tmp.sock   
Hello Sock!

• GNU: No such device or address
• uutils: connect success and print output from socket

Impact

cat changes from "passively reading files" to "actively connecting to local servers", which may trigger server-side side effects or leak data (e.g., accidental connection to privileged Unix sockets) and cause hangs or blocks.