Add XON/XOFF support

src/main.rs

@@ -5,7 +5,10 @@ use std::{
     collections::HashMap,
     os::mikros::{ipc, syscalls},
     path::{Path, PathBuf},
-    sync::Arc,
+    sync::{
+        atomic::{AtomicBool, Ordering},
+        Arc,
+    },
 };
 
 use parking_lot::{Mutex, RwLock};
@@ -16,6 +19,7 @@ struct Pty {
     input_buffer: Mutex<Vec<u8>>,
     output_buffer: Mutex<Vec<u8>>,
     termios: Termios,
+    output_paused: AtomicBool,
 }
 
 impl Pty {
@@ -24,10 +28,14 @@ impl Pty {
             input_buffer: Mutex::new(Vec::new()),
             output_buffer: Mutex::new(Vec::new()),
             termios: Termios::default(),
+            output_paused: AtomicBool::new(false),
         }
     }
 
     fn read_master(&self, len: usize) -> Result<Vec<u8>, ()> {
+        if self.output_paused.load(Ordering::Relaxed) {
+            return Ok(vec![]);
+        }
         let mut output_buffer = self.output_buffer.lock();
         let buf_len = output_buffer.len();
         let rem_buf = output_buffer.split_off(usize::min(buf_len, len));
@@ -37,7 +45,7 @@ impl Pty {
 
     fn write_master(&self, data: &[u8]) -> Result<(), ()> {
         if !self.termios.cflags.cread {
-            return Ok(())
+            return Ok(());
         }
         let mut input_buffer = self.input_buffer.lock();
         let mut output_buffer = self.output_buffer.lock();
@@ -66,6 +74,12 @@ impl Pty {
                     }
                     input_buffer.pop();
                 }
+            } else if byte as char == self.termios.vstop && self.termios.iflags.ixon {
+                self.output_paused.store(true, Ordering::Relaxed);
+            } else if (byte as char == self.termios.vstart && self.termios.iflags.ixon)
+                || (self.termios.iflags.ixany && self.output_paused.load(Ordering::Relaxed))
+            {
+                self.output_paused.store(false, Ordering::Relaxed);
             } else {
                 input_buffer.push(byte);
                 if self.termios.lflags.echo || (byte == b'\n' && self.termios.lflags.echonl) {

src/termios.rs

@@ -27,7 +27,7 @@ impl Default for Iflags {
             istrip: false,
             ixany: false,
             ixoff: false,
-            ixon: false,
+            ixon: true,
             parmark: false,
         }
     }