Merge pull request #845 from memorysafety/cpu

Fix high CPU usage

src/exec/use_pty/parent.rs

@@ -700,7 +700,13 @@ impl Process for ParentClosure {
         match event {
             ParentEvent::Signal => self.on_signal(registry),
             ParentEvent::Tty(poll_event) => {
-                self.tty_pipe.on_left_event(poll_event, registry).ok();
+                // Check if tty which existed is now gone.
+                if self.tty_pipe.left().tcgetsid().is_err() {
+                    dev_warn!("tty gone (closed/detached), ignoring future events");
+                    self.tty_pipe.ignore_events(registry);
+                } else {
+                    self.tty_pipe.on_left_event(poll_event, registry).ok();
+                }
             }
             ParentEvent::Pty(poll_event) => {
                 self.tty_pipe.on_right_event(poll_event, registry).ok();

src/system/term/mod.rs

@@ -145,6 +145,7 @@ pub(crate) trait Terminal: sealed::Sealed {
     fn make_controlling_terminal(&self) -> io::Result<()>;
     fn ttyname(&self) -> io::Result<OsString>;
     fn is_terminal(&self) -> bool;
+    fn tcgetsid(&self) -> io::Result<ProcessId>;
 }
 
 impl<F: AsRawFd> Terminal for F {
@@ -179,6 +180,10 @@ impl<F: AsRawFd> Terminal for F {
     fn is_terminal(&self) -> bool {
         safe_isatty(self.as_raw_fd())
     }
+
+    fn tcgetsid(&self) -> io::Result<ProcessId> {
+        cerr(unsafe { libc::tcgetsid(self.as_raw_fd()) })
+    }
 }
 
 /// Try to get the path of the current TTY