fix(runtime): reset signal handlers in children

Ignored signals do not get reset on exec.
This allows children to properly suspend when needed.

crates/oyster_runtime/src/pipeline.rs

@@ -13,7 +13,8 @@ use nix::{
     fcntl::OFlag,
     libc,
     sys::{
-        signal,
+        signal::{self, SaFlags, SigAction, SigHandler},
+        signalfd::SigSet,
         wait::{self, WaitPidFlag, WaitStatus},
     },
     unistd::{self, Pid},
@@ -47,10 +48,20 @@ impl<'a> PreparedCommand<'a> {
         cmd.stderr(self.stderr.map_or(Stdio::inherit(), Stdio::from));
         cmd.process_group(pgid.as_raw());
 
-        if *pgid == Pid::from_raw(0) {
+        {
+            let pgid = *pgid;
             unsafe {
                 cmd.pre_exec(move || {
+                    if pgid == Pid::from_raw(0) {
                         let _ = unistd::tcsetpgrp(libc::STDIN_FILENO, unistd::getpid());
+                    }
+
+                    let default =
+                        SigAction::new(SigHandler::SigDfl, SaFlags::empty(), SigSet::empty());
+
+                    let _ = signal::sigaction(signal::Signal::SIGTSTP, &default);
+                    let _ = signal::sigaction(signal::Signal::SIGTTOU, &default);
+
                     Ok(())
                 });
             }