stty: add line setting

src/uu/stty/src/stty.rs

@@ -19,6 +19,7 @@ use nix::{ioctl_read_bad, ioctl_write_ptr_bad};
 use std::collections::HashMap;
 use std::fs::File;
 use std::io::{self, Stdout, stdout};
+use std::num::IntErrorKind;
 use std::os::fd::{AsFd, BorrowedFd};
 use std::os::unix::fs::OpenOptionsExt;
 use std::os::unix::io::{AsRawFd, RawFd};
@@ -113,6 +114,7 @@ enum ControlCharMappingError {
 enum SpecialSetting {
     Rows(u16),
     Cols(u16),
+    Line(u8),
 }
 
 enum PrintSetting {
@@ -301,6 +303,22 @@ fn stty(opts: &Options) -> UResult<()> {
                         ));
                     }
                 }
+            } else if *arg == "line" {
+                match args_iter.next() {
+                    Some(line) => match parse_u8_or_err(line) {
+                        Ok(n) => valid_args.push(ArgOptions::Special(SpecialSetting::Line(n))),
+                        Err(e) => return Err(USimpleError::new(1, e)),
+                    },
+                    None => {
+                        return Err(USimpleError::new(
+                            1,
+                            get_message_with_args(
+                                "stty-error-missing-argument",
+                                HashMap::from([("arg".to_string(), arg.to_string())]),
+                            ),
+                        ));
+                    }
+                }
             // baud rate setting
             } else if let Some(baud_flag) = string_to_baud(arg) {
                 valid_args.push(ArgOptions::Flags(baud_flag));
@@ -394,7 +412,7 @@ fn stty(opts: &Options) -> UResult<()> {
                 ArgOptions::Mapping(mapping) => apply_char_mapping(&mut termios, mapping),
                 ArgOptions::Flags(flag) => apply_setting(&mut termios, flag),
                 ArgOptions::Special(setting) => {
-                    apply_special_setting(setting, opts.file.as_raw_fd())?;
+                    apply_special_setting(&mut termios, setting, opts.file.as_raw_fd())?;
                 }
                 ArgOptions::Print(setting) => {
                     print_special_setting(setting, opts.file.as_raw_fd())?;
@@ -411,6 +429,21 @@ fn stty(opts: &Options) -> UResult<()> {
     Ok(())
 }
 
+// GNU uses different error messages if values overflow or underflow a u8
+// this function returns the appropriate error message in the case of overflow or underflow, or u8 on success
+fn parse_u8_or_err(arg: &str) -> Result<u8, String> {
+    arg.parse::<u8>().map_err(|e| match e.kind() {
+        IntErrorKind::PosOverflow => get_message_with_args(
+            "stty-error-invalid-integer-argument-value-too-large",
+            HashMap::from([("value".to_string(), format!("'{}'", arg))]),
+        ),
+        _ => get_message_with_args(
+            "stty-error-invalid-integer-argument",
+            HashMap::from([("value".to_string(), format!("'{}'", arg))]),
+        ),
+    })
+}
+
 // GNU uses an unsigned 32 bit integer for row/col sizes, but then wraps around 16 bits
 // this function returns Some(n), where n is a u16 row/col size, or None if the string arg cannot be parsed as a u32
 fn parse_rows_cols(arg: &str) -> Option<u16> {
@@ -747,12 +780,23 @@ fn apply_char_mapping(termios: &mut Termios, mapping: &(SpecialCharacterIndices,
     termios.control_chars[mapping.0 as usize] = mapping.1;
 }
 
-fn apply_special_setting(setting: &SpecialSetting, fd: i32) -> nix::Result<()> {
+fn apply_special_setting(
+    _termios: &mut Termios,
+    setting: &SpecialSetting,
+    fd: i32,
+) -> nix::Result<()> {
     let mut size = TermSize::default();
     unsafe { tiocgwinsz(fd, &raw mut size)? };
     match setting {
         SpecialSetting::Rows(n) => size.rows = *n,
         SpecialSetting::Cols(n) => size.columns = *n,
+        SpecialSetting::Line(_n) => {
+            // nix only defines Termios's `line_discipline` field on these platforms
+            #[cfg(any(target_os = "linux", target_os = "android"))]
+            {
+                _termios.line_discipline = *_n;
+            }
+        }
     }
     unsafe { tiocswinsz(fd, &raw mut size)? };
     Ok(())

tests/by-util/test_stty.rs

@@ -241,3 +241,22 @@ fn row_column_sizes() {
         .fails()
         .stderr_contains("missing argument to 'rows'");
 }
+
+#[test]
+#[cfg(any(target_os = "linux", target_os = "android"))]
+fn line() {
+    new_ucmd!()
+        .args(&["line"])
+        .fails()
+        .stderr_contains("missing argument to 'line'");
+
+    new_ucmd!()
+        .args(&["line", "-1"])
+        .fails()
+        .stderr_contains("invalid integer argument: '-1'");
+
+    new_ucmd!()
+        .args(&["line", "256"])
+        .fails()
+        .stderr_contains("invalid integer argument: '256'");
+}