stty: report write errors instead of panicking (#10552)

src/uu/stty/Cargo.toml

@@ -19,6 +19,7 @@ doctest = false
 clap = { workspace = true }
 fluent = { workspace = true }
 nix = { workspace = true, features = ["ioctl", "term"] }
+thiserror = { workspace = true }
 uucore = { workspace = true, features = ["parser"] }
 
 [build-dependencies]

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

@@ -16,6 +16,7 @@ stty-error-invalid-speed = invalid {$arg} '{$speed}'
 stty-error-invalid-argument = invalid argument '{$arg}'
 stty-error-invalid-integer-argument = invalid integer argument: {$value}
 stty-error-invalid-integer-argument-value-too-large = invalid integer argument: {$value}: Value too large for defined data type
+stty-error-write-error = write error
 
 # Output format strings
 stty-output-speed = speed {$speed} baud;

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

@@ -16,6 +16,7 @@ stty-error-invalid-speed = {$arg} invalide '{$speed}'
 stty-error-invalid-argument = argument invalide '{$arg}'
 stty-error-invalid-integer-argument = argument entier invalide : {$value}
 stty-error-invalid-integer-argument-value-too-large = argument entier invalide : {$value} : Valeur trop grande pour le type de données défini
+stty-error-write-error = erreur d'écriture
 
 # Chaînes de format de sortie
 stty-output-speed = vitesse {$speed} bauds ;

src/uu/stty/src/main.rs

@@ -3,4 +3,7 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-uucore::bin!(uu_stty);
+// All output paths in uu_stty handle stdout write errors themselves and end
+// with a newline (draining the line buffer), so the defensive exit-time flush
+// is not necessary and would report write errors a second time.
+uucore::bin!(uu_stty, no_flush);

src/uu/stty/src/stty.rs

@@ -37,12 +37,13 @@ use nix::sys::termios::{
 use nix::{ioctl_read_bad, ioctl_write_ptr_bad};
 use std::cmp::Ordering;
 use std::fs::File;
-use std::io::{self, Stdin, stdin, stdout};
+use std::io::{self, Stdin, Write, stdin, stdout};
 use std::num::IntErrorKind;
 use std::os::fd::{AsFd, BorrowedFd};
 use std::os::unix::fs::OpenOptionsExt;
 use std::os::unix::io::{AsRawFd, RawFd};
-use uucore::error::{FromIo, UError, UResult, USimpleError, UUsageError};
+use thiserror::Error;
+use uucore::error::{FromIo, UError, UResult, USimpleError, UUsageError, strip_errno};
 use uucore::format_usage;
 use uucore::parser::num_parser::ExtendedParser;
 use uucore::translate;
@@ -552,17 +553,27 @@ fn check_flag_group<T>(flag: &Flag<T>, remove: bool) -> bool {
     remove && flag.group.is_some()
 }
 
-fn print_special_setting(setting: &PrintSetting, fd: i32) -> nix::Result<()> {
+fn print_special_setting(setting: &PrintSetting, fd: i32) -> UResult<()> {
     match setting {
         PrintSetting::Size => {
             let mut size = TermSize::default();
             unsafe { tiocgwinsz(fd, &raw mut size)? };
-            println!("{} {}", size.rows, size.columns);
+            writeln!(stdout(), "{} {}", size.rows, size.columns).map_err(SttyError::Write)?;
         }
     }
     Ok(())
 }
 
+#[derive(Debug, Error)]
+enum SttyError {
+    /// A write to stdout failed. Report instead of panicking the way
+    /// 'print!' family of macros does.
+    #[error("{}: {}", translate!("stty-error-write-error"), strip_errno(.0))]
+    Write(io::Error),
+}
+
+impl UError for SttyError {}
+
 /// Handles line wrapping for stty output to fit within terminal width
 struct WrappedPrinter {
     width: usize,
@@ -593,29 +604,31 @@ impl WrappedPrinter {
         }
     }
 
-    fn print(&mut self, token: &str) {
+    fn print(&mut self, token: &str) -> UResult<()> {
         let token_len = self.prefix().chars().count() + token.chars().count();
         if self.current > 0 && self.current + token_len > self.width {
-            println!();
+            writeln!(stdout()).map_err(SttyError::Write)?;
             self.current = 0;
             self.first_in_line = true;
         }
 
-        print!("{}{token}", self.prefix());
+        write!(stdout(), "{}{token}", self.prefix()).map_err(SttyError::Write)?;
         self.current += token_len;
         self.first_in_line = false;
+        Ok(())
     }
 
     fn prefix(&self) -> &str {
         if self.first_in_line { "" } else { " " }
     }
 
-    fn flush(&mut self) {
+    fn flush(&mut self) -> UResult<()> {
         if self.current > 0 {
-            println!();
+            writeln!(stdout()).map_err(SttyError::Write)?;
             self.current = 0;
             self.first_in_line = false;
         }
+        Ok(())
     }
 }
 
@@ -628,7 +641,7 @@ fn print_terminal_size(
     opts: &Options,
     window_size: Option<&TermSize>,
     term_size: Option<&TermSize>,
-) -> nix::Result<()> {
+) -> UResult<()> {
     // GNU linked against glibc 2.42 provides us baudrate 51 which panics cfgetospeed
     #[cfg(not(target_os = "linux"))]
     let speed = nix::sys::termios::cfgetospeed(termios);
@@ -658,7 +671,7 @@ fn print_terminal_size(
             not(all(target_arch = "powerpc64", target_endian = "big"))
         )
     ))]
-    printer.print(&translate!("stty-output-speed", "speed" => speed));
+    printer.print(&translate!("stty-output-speed", "speed" => speed))?;
 
     // Big-endian Linux PowerPC uses BaudRate enum, need to convert to display format
     #[cfg(target_os = "linux")]
@@ -673,15 +686,15 @@ fn print_terminal_size(
             .find(|(_, rate)| *rate == speed)
             .map(|(text, _)| *text)
             .unwrap_or("unknown");
-        printer.print(&translate!("stty-output-speed", "speed" => speed_str));
+        printer.print(&translate!("stty-output-speed", "speed" => speed_str))?;
     }
 
     // Other platforms need to use the baud rate enum, so printing the right value
     // becomes slightly more complicated.
     #[cfg(not(any(target_os = "linux", bsd)))]
     for (text, baud_rate) in BAUD_RATES {
         if *baud_rate == speed {
-            printer.print(&translate!("stty-output-speed", "speed" => (*text)));
+            printer.print(&translate!("stty-output-speed", "speed" => (*text)))?;
             break;
         }
     }
@@ -690,7 +703,7 @@ fn print_terminal_size(
         let term_size = term_size.as_ref().expect("terminal size should be set");
         printer.print(
             &translate!("stty-output-rows-columns", "rows" => term_size.rows, "columns" => term_size.columns),
-        );
+        )?;
     }
 
     #[cfg(any(target_os = "linux", target_os = "redox"))]
@@ -699,9 +712,9 @@ fn print_terminal_size(
         // so we get the underlying libc::termios struct to get that information.
         let libc_termios: nix::libc::termios = termios.clone().into();
         let line = libc_termios.c_line;
-        printer.print(&translate!("stty-output-line", "line" => line));
+        printer.print(&translate!("stty-output-line", "line" => line))?;
     }
-    printer.flush();
+    printer.flush()?;
     Ok(())
 }
 
@@ -859,7 +872,7 @@ fn print_control_chars(
     termios: &Termios,
     opts: &Options,
     term_size: Option<&TermSize>,
-) -> nix::Result<()> {
+) -> UResult<()> {
     if !opts.all {
         // Print only control chars that differ from sane defaults
         let mut printer = WrappedPrinter::new(term_size);
@@ -871,10 +884,10 @@ fn print_control_chars(
                 printer.print(&format!(
                     "{text} = {};",
                     control_char_to_string(current_val)?
-                ));
+                ))?;
             }
         }
-        printer.flush();
+        printer.flush()?;
         return Ok(());
     }
 
@@ -883,28 +896,31 @@ fn print_control_chars(
         printer.print(&format!(
             "{text} = {};",
             control_char_to_string(termios.control_chars[*cc_index as usize])?
-        ));
+        ))?;
     }
     printer.print(&translate!("stty-output-min-time",
         "min" => termios.control_chars[S::VMIN as usize],
         "time" => termios.control_chars[S::VTIME as usize]
-    ));
-    printer.flush();
+    ))?;
+    printer.flush()?;
     Ok(())
 }
 
-fn print_in_save_format(termios: &Termios) {
-    print!(
+fn print_in_save_format(termios: &Termios) -> UResult<()> {
+    write!(
+        stdout(),
         "{:x}:{:x}:{:x}:{:x}",
         termios.input_flags.bits(),
         termios.output_flags.bits(),
         termios.control_flags.bits(),
         termios.local_flags.bits()
-    );
+    )
+    .map_err(SttyError::Write)?;
     for cc in termios.control_chars {
-        print!(":{cc:x}");
+        write!(stdout(), ":{cc:x}").map_err(SttyError::Write)?;
     }
-    println!();
+    writeln!(stdout()).map_err(SttyError::Write)?;
+    Ok(())
 }
 
 /// Gets terminal size using the tiocgwinsz ioctl system call.
@@ -914,9 +930,9 @@ fn get_terminal_size(fd: RawFd) -> nix::Result<TermSize> {
     unsafe { tiocgwinsz(fd, &raw mut term_size) }.map(|_| term_size)
 }
 
-fn print_settings(termios: &Termios, opts: &Options) -> nix::Result<()> {
+fn print_settings(termios: &Termios, opts: &Options) -> UResult<()> {
     if opts.save {
-        print_in_save_format(termios);
+        print_in_save_format(termios)?;
     } else {
         let device_fd = opts.file.as_raw_fd();
         let term_size = if opts.all {
@@ -934,10 +950,10 @@ fn print_settings(termios: &Termios, opts: &Options) -> nix::Result<()> {
 
         print_terminal_size(termios, opts, window_size.as_ref(), term_size.as_ref())?;
         print_control_chars(termios, opts, window_size.as_ref())?;
-        print_flags(termios, opts, CONTROL_FLAGS, window_size.as_ref());
-        print_flags(termios, opts, INPUT_FLAGS, window_size.as_ref());
-        print_flags(termios, opts, OUTPUT_FLAGS, window_size.as_ref());
-        print_flags(termios, opts, LOCAL_FLAGS, window_size.as_ref());
+        print_flags(termios, opts, CONTROL_FLAGS, window_size.as_ref())?;
+        print_flags(termios, opts, INPUT_FLAGS, window_size.as_ref())?;
+        print_flags(termios, opts, OUTPUT_FLAGS, window_size.as_ref())?;
+        print_flags(termios, opts, LOCAL_FLAGS, window_size.as_ref())?;
     }
     Ok(())
 }
@@ -947,7 +963,7 @@ fn print_flags<T: TermiosFlag>(
     opts: &Options,
     flags: &[Flag<T>],
     term_size: Option<&TermSize>,
-) {
+) -> UResult<()> {
     let mut printer = WrappedPrinter::new(term_size);
     for &Flag {
         name,
@@ -963,17 +979,17 @@ fn print_flags<T: TermiosFlag>(
         let val = flag.is_in(termios, group);
         if group.is_some() {
             if val && (!sane || opts.all) {
-                printer.print(name);
+                printer.print(name)?;
             }
         } else if opts.all || val != sane {
             if !val {
-                printer.print(&format!("-{name}"));
+                printer.print(&format!("-{name}"))?;
                 continue;
             }
-            printer.print(name);
+            printer.print(name)?;
         }
     }
-    printer.flush();
+    printer.flush()
 }
 
 /// Apply a single setting

tests/by-util/test_stty.rs

@@ -1719,3 +1719,23 @@ fn test_columns_env_wrapping() {
         );
     }
 }
+
+#[test]
+#[cfg(target_os = "linux")]
+fn test_write_error_to_dev_full() {
+    // stty must report write errors like GNU instead of panicking.
+    for args in [&[][..], &["--all"][..], &["--save"][..], &["size"][..]] {
+        let (path, _controller, _replica) = pty_path();
+        let dev_full = std::fs::OpenOptions::new()
+            .write(true)
+            .open("/dev/full")
+            .expect("/dev/full must exists on Linux");
+
+        new_ucmd!()
+            .args(&["--file", &path])
+            .args(args)
+            .set_stdout(dev_full)
+            .fails_with_code(1)
+            .stderr_only("stty: write error: No space left on device\n");
+    }
+}