feat(runtime): set foreground job properly

crates/oyster/src/main.rs

@@ -5,7 +5,7 @@ use oyster_parser::ast::Code;
 use oyster_runtime::{Shell, Status};
 
 fn main() {
-    let mut shell = Shell::default();
+    let mut shell = Shell::new().unwrap();
     let mut exit_code = Status::SUCCESS;
 
     loop {

crates/oyster_runtime/Cargo.toml

@@ -13,7 +13,7 @@ thiserror = "1.0.35"
 [dependencies.nix]
 version = "~0.25.0"
 default-features = false
-features = [ "fs", "ioctl", "process", "term" ]
+features = [ "fs", "ioctl", "process", "signal", "term" ]
 
 [dev-dependencies]
 insta = "^1.15.0"

crates/oyster_runtime/src/lib.rs

@@ -5,6 +5,10 @@ mod pipeline;
 
 use std::io;
 
+use nix::sys::{
+    signal::{self, SaFlags, SigAction, SigHandler, Signal},
+    signalfd::SigSet,
+};
 use oyster_parser::ast;
 use thiserror::Error;
 
@@ -33,12 +37,25 @@ pub enum RuntimeError {
 
     #[error("failed to spawn process: {0}")]
     SpawnFailed(#[source] io::Error),
+
+    #[error("waitpid error: {0}")]
+    WaidPid(nix::Error),
 }
 
-#[derive(Default)]
 pub struct Shell;
 
 impl Shell {
+    pub fn new() -> Result<Shell, nix::Error> {
+        let ignore = SigAction::new(SigHandler::SigIgn, SaFlags::empty(), SigSet::empty());
+
+        unsafe {
+            signal::sigaction(Signal::SIGTSTP, &ignore)?;
+            signal::sigaction(Signal::SIGTTOU, &ignore)?;
+        }
+
+        Ok(Shell)
+    }
+
     pub fn run<'a>(&mut self, code: &'a ast::Code) -> Result<Status, RuntimeError> {
         let mut last_status = Status::SUCCESS;
 

crates/oyster_runtime/src/pipeline.rs

@@ -3,16 +3,16 @@ use std::{
     ffi::{OsStr, OsString},
     fs::File,
     io,
-    os::unix::{
-        io::FromRawFd,
-        process::{CommandExt, ExitStatusExt},
-    },
+    os::unix::{io::FromRawFd, process::CommandExt},
     process::{Child, Command, Stdio},
     slice::Iter,
 };
 
 use nix::{
+    errno::Errno,
     fcntl::OFlag,
+    libc,
+    sys::wait::{self, WaitPidFlag, WaitStatus},
     unistd::{self, Pid},
 };
 use oyster_parser::ast::{self, Redirect};
@@ -44,6 +44,15 @@ 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) {
+            unsafe {
+                cmd.pre_exec(move || {
+                    let _ = unistd::tcsetpgrp(libc::STDIN_FILENO, unistd::getpid());
+                    Ok(())
+                });
+            }
+        }
+
         let child = match cmd.spawn() {
             Ok(child) => child,
             Err(err) => {
@@ -92,7 +101,6 @@ impl Shell {
         &mut self,
         pipeline: &ast::Pipeline,
     ) -> Result<Status, RuntimeError> {
-        let mut children = Vec::with_capacity(pipeline.0.len());
         let mut cmds = pipeline.0.iter().map(PreparedCommand::from);
         let mut pgid = Pid::from_raw(0);
 
@@ -106,28 +114,40 @@ impl Shell {
                 Redirect::Stdout => last_cmd.stdout = Some(input),
             }
 
-            children.push(last_cmd.spawn(&mut pgid)?);
+            last_cmd.spawn(&mut pgid)?;
 
             last_cmd = cmd;
         }
 
-        children.push(last_cmd.spawn(&mut pgid)?);
+        last_cmd.spawn(&mut pgid)?;
 
         // TODO: kill children if error occured
-        // TODO: set foreground group then wait for foreground group
 
-        let mut last_status = Status::SUCCESS;
-        for mut c in children {
-            // TODO: handle error
-            let status = c.wait().unwrap();
-            last_status = Status(
-                status
-                    .code()
-                    .unwrap_or_else(|| Status::SIG_BASE.0 + status.signal().unwrap()),
-            );
+        let status = wait_pgid(pgid)?;
+        let _ = unistd::tcsetpgrp(libc::STDIN_FILENO, unistd::getpgid(None).unwrap());
+
+        Ok(status)
+    }
+}
+
+/// Wait for all processes of the specified job to terminate.
+fn wait_pgid(pgid: Pid) -> Result<Status, RuntimeError> {
+    let pgid = Pid::from_raw(-pgid.as_raw());
+    let mut last_status = Status::SUCCESS;
+
+    loop {
+        match wait::waitpid(pgid, Some(WaitPidFlag::WUNTRACED)) {
+            Ok(WaitStatus::Exited(_, code)) => last_status = Status(code),
+            Ok(WaitStatus::Signaled(_, signal, _)) => {
+                last_status = Status(Status::SIG_BASE.0 + signal as i32)
+            }
+            Ok(WaitStatus::Stopped(_, _)) => todo!("put job into background job list"),
+            Ok(_) => (),
+            Err(err) => match err {
+                Errno::ECHILD => break Ok(last_status), // no more children
+                _ => break Err(RuntimeError::WaidPid(err)),
+            },
         }
-
-        Ok(last_status)
     }
 }
 

crates/oyster_runtime/tests/it/pipeline.rs

@@ -76,7 +76,7 @@ fn simple_command() {
     };
 
     let actual = collect_output(|| {
-        let mut shell = Shell::default();
+        let mut shell = Shell::new().unwrap();
         shell.run(&ast).unwrap();
     });
 
@@ -107,7 +107,7 @@ fn pipeline() {
     };
 
     let actual = collect_output(|| {
-        let mut shell = Shell::default();
+        let mut shell = Shell::new().unwrap();
         shell.run(&ast).unwrap();
     });
 
@@ -126,7 +126,7 @@ fn command_not_found() {
     };
 
     // XXX: this relies on the command actually not existing, as unsetting PATH is rather complex
-    let mut shell = Shell::default();
+    let mut shell = Shell::new().unwrap();
     let actual = shell.run(&ast);
 
     assert_snapshot!(actual);
@@ -143,7 +143,7 @@ fn permission_denied() {
         )]))])
     };
 
-    let mut shell = Shell::default();
+    let mut shell = Shell::new().unwrap();
     let actual = shell.run(&ast);
 
     assert_snapshot!(actual);
@@ -164,7 +164,7 @@ fn multipart_word() {
     };
 
     let actual = collect_output(|| {
-        let mut shell = Shell::default();
+        let mut shell = Shell::new().unwrap();
         shell.run(&ast).unwrap();
     });