Terminal: restore original termios on panic and terminating signals

src/job_control.rs

@@ -10,6 +10,8 @@ use std::os::unix::process::CommandExt;
 
 use libc;
 
+use crate::tty;
+
 static FG_PGID: Lazy<AtomicI32> = Lazy::new(|| AtomicI32::new(0));
 
 pub fn init_signal_handlers() {
@@ -21,6 +23,9 @@ pub fn init_signal_handlers() {
                 libc::SIGCHLD,
                 libc::SIGINT,
                 libc::SIGTSTP,
+                libc::SIGTERM,
+                libc::SIGQUIT,
+                libc::SIGHUP,
             ]) {
                 Ok(s) => s,
                 Err(e) => {
@@ -53,6 +58,13 @@ pub fn init_signal_handlers() {
                             unsafe { libc::kill(-(pgid as libc::pid_t), libc::SIGTSTP) };
                         }
                     }
+                    libc::SIGTERM | libc::SIGQUIT | libc::SIGHUP => {
+                        // Best-effort: restore terminal state before exiting
+                        crate::tty::restore_original_termios();
+                        // Exit with a code indicating signal termination.
+                        // Use 128 + signo as conventional shell exit code for signals.
+                        std::process::exit(128 + signal);
+                    }
                     _ => {}
                 }
             }

src/main.rs

@@ -3,6 +3,7 @@ mod parser;
 mod job_control;
 mod terminal;
 mod wasm_host;
+mod tty;
 
 use crate::dotfiles::import_dotfiles;
 use crate::wasm_host::{load_plugin_manifest, WasmPlugin};
@@ -16,6 +17,21 @@ fn main() {
 
     // Initialize job control and signal handlers
     job_control::init_signal_handlers();
+
+    // Save the current terminal attributes so we can restore them on panic/abnormal exit.
+    if let Err(e) = tty::save_original_termios() {
+        eprintln!("warning: failed to save terminal settings: {}", e);
+    }
+
+    // Install a panic hook that restores the terminal before printing panic info / exiting.
+    let default_hook = std::panic::take_hook();
+    std::panic::set_hook(Box::new(move |info| {
+        // best-effort restore
+        crate::tty::restore_original_termios();
+        // call the default hook so panic info still appears
+        default_hook(info);
+    }));
+
     if let Ok(home) = std::env::var("HOME") {
         match import_dotfiles(std::path::Path::new(&home)) {
             Ok(imports) => {

src/tty.rs

@@ -0,0 +1,35 @@
+use once_cell::sync::Lazy;
+use std::sync::Mutex;
+use std::io;
+
+/// Stores the original terminal attributes so we can restore them on panic/signals.
+///
+/// This is intentionally best-effort: saving/restoring termios can fail (e.g. stdin closed),
+/// but restoring when possible prevents leaving the user's terminal in an unusable state.
+static ORIGINAL_TERMIOS: Lazy<Mutex<Option<libc::termios>>> = Lazy::new(|| Mutex::new(None));
+
+/// Save the current terminal attributes once. Safe to call multiple times.
+pub fn save_original_termios() -> io::Result<()> {
+    let mut guard = ORIGINAL_TERMIOS.lock().unwrap();
+    if guard.is_some() {
+        return Ok(());
+    }
+
+    let mut t: libc::termios = unsafe { std::mem::zeroed() };
+    let r = unsafe { libc::tcgetattr(libc::STDIN_FILENO, &mut t as *mut libc::termios) };
+    if r != 0 {
+        return Err(io::Error::last_os_error());
+    }
+
+    *guard = Some(t);
+    Ok(())
+}
+
+/// Attempt to restore the saved termios. Best-effort; ignore errors.
+pub fn restore_original_termios() {
+    let guard = ORIGINAL_TERMIOS.lock().unwrap();
+    if let Some(orig) = guard.as_ref() {
+        // use TCSANOW to apply immediately; ignore return value (best-effort)
+        let _ = unsafe { libc::tcsetattr(libc::STDIN_FILENO, libc::TCSANOW, orig as *const libc::termios) };
+    }
+}