stty: clear grouped flags before setting a new value

src/uu/stty/src/stty.rs

@@ -3,7 +3,7 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-// spell-checker:ignore clocal erange tcgetattr tcsetattr tcsanow tiocgwinsz tiocswinsz cfgetospeed cfsetospeed ushort vmin vtime cflag lflag ispeed ospeed
+// spell-checker:ignore clocal erange tcgetattr tcsetattr tcsanow tiocgwinsz tiocswinsz cfgetospeed cfsetospeed ushort vmin vtime cflag lflag ispeed ospeed openpty
 // spell-checker:ignore parenb parodd cmspar hupcl cstopb cread clocal crtscts CSIZE
 // spell-checker:ignore ignbrk brkint ignpar parmrk inpck istrip inlcr igncr icrnl ixoff ixon iuclc ixany imaxbel iutf
 // spell-checker:ignore opost olcuc ocrnl onlcr onocr onlret ofdel nldly crdly tabdly bsdly vtdly ffdly ofill
@@ -101,6 +101,16 @@ impl<T> Flag<T> {
         self.sane = true;
         self
     }
+
+    fn apply(&self, termios: &mut Termios, enabled: bool)
+    where
+        T: TermiosFlag,
+    {
+        if enabled && let Some(group) = self.group {
+            group.apply(termios, false);
+        }
+        self.flag.apply(termios, enabled);
+    }
 }
 
 trait TermiosFlag: Copy {
@@ -892,16 +902,16 @@ fn apply_setting(termios: &mut Termios, setting: &AllFlags) -> nix::Result<()> {
     match setting {
         AllFlags::Baud(_, _) => apply_baud_rate_flag(termios, setting)?,
         AllFlags::ControlFlags((setting, disable)) => {
-            setting.flag.apply(termios, !disable);
+            setting.apply(termios, !disable);
         }
         AllFlags::InputFlags((setting, disable)) => {
-            setting.flag.apply(termios, !disable);
+            setting.apply(termios, !disable);
         }
         AllFlags::LocalFlags((setting, disable)) => {
-            setting.flag.apply(termios, !disable);
+            setting.apply(termios, !disable);
         }
         AllFlags::OutputFlags((setting, disable)) => {
-            setting.flag.apply(termios, !disable);
+            setting.apply(termios, !disable);
         }
     }
     Ok(())
@@ -1216,6 +1226,29 @@ impl TermiosFlag for LocalFlags {
 mod tests {
     use super::*;
 
+    #[test]
+    #[cfg(not(any(target_os = "aix", target_os = "redox", target_os = "fuchsia")))]
+    fn test_apply_character_size_preserves_other_control_flags() {
+        let pty = nix::pty::openpty(None, None).unwrap();
+        let mut termios = tcgetattr(&pty.slave).unwrap();
+        let other_flags = ControlFlags::CLOCAL | ControlFlags::CREAD;
+        let sizes = [
+            ("cs5", ControlFlags::CS5),
+            ("cs6", ControlFlags::CS6),
+            ("cs7", ControlFlags::CS7),
+            ("cs8", ControlFlags::CS8),
+        ];
+
+        for (_, initial) in sizes {
+            for (name, expected) in sizes {
+                termios.control_flags = initial | other_flags;
+                let flag = CONTROL_FLAGS.iter().find(|flag| flag.name == name).unwrap();
+                apply_setting(&mut termios, &AllFlags::ControlFlags((flag, false))).unwrap();
+                assert_eq!(termios.control_flags, expected | other_flags);
+            }
+        }
+    }
+
     // Essential unit tests for complex internal parsing and logic functions.
 
     // Control character parsing tests

tests/by-util/test_stty.rs

@@ -3,7 +3,7 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-// spell-checker:ignore parenb parmrk ixany iuclc onlcr ofdel icanon noflsh econl igpar ispeed ospeed NCCS nonhex gstty notachar cbreak evenp oddp CSIZE
+// spell-checker:ignore parenb parmrk ixany iuclc onlcr ofdel icanon noflsh econl igpar ispeed ospeed NCCS nonhex gstty notachar cbreak evenp oddp CSIZE tcgetattr CRDLY
 
 #![cfg(unix)]
 
@@ -46,6 +46,73 @@ fn test_all_flag() {
     }
 }
 
+#[cfg(target_os = "linux")]
+#[test]
+fn test_character_size_cs8_then_cs7() {
+    use rustix::termios::{ControlModes, tcgetattr};
+
+    let (path, _controller, replica) = pty_path();
+    new_ucmd!()
+        .args(&["--file", &path, "cs8"])
+        .succeeds()
+        .no_output();
+
+    // Applying a saved state bypasses grouped flag handling while using the same
+    // libc interface, whose treatment of unsupported PTY settings can vary.
+    let original = new_ucmd!()
+        .args(&["--file", &path, "--save"])
+        .succeeds()
+        .stdout_move_str();
+    let mut expected: Vec<_> = original.trim().split(':').map(str::to_owned).collect();
+    let control_modes = tcgetattr(&replica).unwrap().control_modes;
+    expected[2] = format!(
+        "{:x}",
+        ((control_modes - ControlModes::CSIZE) | ControlModes::CS7).bits()
+    );
+    let expected_result = new_ucmd!()
+        .args(&["--file", &path, &expected.join(":")])
+        .run();
+    let expected_size = tcgetattr(&replica).unwrap().control_modes & ControlModes::CSIZE;
+    new_ucmd!()
+        .args(&["--file", &path, original.trim()])
+        .succeeds()
+        .no_output();
+
+    let result = new_ucmd!().args(&["--file", &path, "cs7"]).run();
+    result
+        .code_is(expected_result.code())
+        .no_stdout()
+        .stderr_is(expected_result.stderr_str());
+    assert_eq!(
+        tcgetattr(&replica).unwrap().control_modes & ControlModes::CSIZE,
+        expected_size
+    );
+}
+
+#[cfg(target_os = "linux")]
+#[rstest::rstest]
+#[case("cr3", "cr0", rustix::termios::OutputModes::CR0)]
+#[case("cr3", "cr1", rustix::termios::OutputModes::CR1)]
+#[case("cr1", "cr2", rustix::termios::OutputModes::CR2)]
+#[case("cr2", "cr3", rustix::termios::OutputModes::CR3)]
+fn test_grouped_output_flags(
+    #[case] initial: &str,
+    #[case] setting: &str,
+    #[case] expected: rustix::termios::OutputModes,
+) {
+    use rustix::termios::{OutputModes, tcgetattr};
+
+    let (path, _controller, replica) = pty_path();
+    new_ucmd!()
+        .args(&["--file", &path, "opost", initial, setting])
+        .succeeds()
+        .no_output();
+
+    let termios = tcgetattr(&replica).unwrap();
+    assert_eq!(termios.output_modes & OutputModes::CRDLY, expected);
+    assert!(termios.output_modes.contains(OutputModes::OPOST));
+}
+
 #[test]
 fn test_sane() {
     let (path, _controller, _replica) = pty_path();