Import scripted test for wait built-in

The test script was copied from:
https://github.com/magicant/yash/blob/8ed979daa54384b40728617cc52e78490cb72455/tests/wait-p.tst

The test cases require a pseudo-terminal because they use the job
control facilities. The pseudo-terminal handling code is based on:
https://github.com/magicant/pseudo-terminal-wrapper

yash/Cargo.toml

@@ -32,4 +32,5 @@ yash-syntax = { path = "../yash-syntax", version = "0.7.0" }
 [dev-dependencies]
 assert_matches = "1.5.0"
 fuzed-iterator = "1.0.0"
+nix = { version = "0.27.0", features = ["fs", "process", "term"] }
 tempfile = "3.8.0"

yash/tests/pty/mod.rs

@@ -0,0 +1,101 @@
+// This file is part of yash, an extended POSIX shell.
+// Copyright (C) 2023 WATANABE Yuki
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+//! Pseudo-terminal handling for scripted tests
+//!
+//! This module contains functionality to run a test subject in a
+//! pseudo-terminal and communicate with it via the master side of the
+//! pseudo-terminal. This is used for tests that depends on terminal
+//! facilities such as job control.
+
+use crate::run_with_preexec;
+use nix::fcntl::{open, OFlag};
+use nix::libc;
+use nix::pty::{grantpt, posix_openpt, ptsname, unlockpt, PtyMaster};
+use nix::sys::stat::Mode;
+use nix::unistd::{close, getpgrp, setsid, tcgetpgrp};
+use std::ffi::c_int;
+use std::os::fd::{AsRawFd as _, FromRawFd as _, OwnedFd};
+use std::path::{Path, PathBuf};
+use std::sync::Mutex;
+
+/// Runs a test subject in a pseudo-terminal.
+pub fn run_with_pty(name: &str) {
+    let master = prepare_pty_master();
+    let slave_path = pty_slave_path(&master);
+    let slave = open_pty_slave(&slave_path);
+    let raw_master = master.as_raw_fd();
+    let raw_slave = slave.as_raw_fd();
+
+    unsafe {
+        run_with_preexec(name, move || {
+            close(raw_master)?;
+            prepare_as_slave(&slave_path)?;
+            close(raw_slave)?;
+            Ok(())
+        });
+    }
+}
+
+/// Prepares the master side of a pseudo-terminal.
+fn prepare_pty_master() -> PtyMaster {
+    let master = posix_openpt(OFlag::O_RDWR | OFlag::O_NOCTTY).expect("posix_openpt failed");
+    grantpt(&master).expect("grantpt failed");
+    unlockpt(&master).expect("unlockpt failed");
+    master
+}
+
+/// Mutex to serialize access to `ptsname`, which is not thread-safe.
+static PTSNAME_MUTEX: Mutex<()> = Mutex::new(());
+
+/// Returns the path of the slave side of a pseudo-terminal.
+fn pty_slave_path(master: &PtyMaster) -> PathBuf {
+    let _lock = PTSNAME_MUTEX.lock().expect("PTSNAME_MUTEX poisoned");
+    unsafe { ptsname(master) }.expect("ptsname failed").into()
+}
+
+/// Opens the slave side of a pseudo-terminal.
+fn open_pty_slave(path: &Path) -> OwnedFd {
+    let raw_fd = open(path, OFlag::O_RDWR | OFlag::O_NOCTTY, Mode::empty()).expect("open failed");
+    unsafe { OwnedFd::from_raw_fd(raw_fd) }
+}
+
+/// Prepares the slave side of a pseudo-terminal.
+///
+/// No memory allocation or panicking is allowed in this function because it is
+/// called in a child process.
+fn prepare_as_slave(slave_path: &Path) -> nix::Result<()> {
+    setsid()?;
+
+    // How to become the controlling process of a slave pseudo-terminal is
+    // implementation-dependent. We support two implementation schemes:
+    // (1) A process automatically becomes the controlling process when it
+    // first opens the terminal.
+    // (2) A process needs to use the TIOCSCTTY ioctl system call.
+    // There is a race condition in both schemes: an unrelated process could
+    // become the controlling process before we do, in which case the slave is
+    // not our controlling terminal and therefore we should abort.
+    let raw_fd = open(slave_path, OFlag::O_RDWR, Mode::empty())?;
+    // Although TIOCSCTTY is available in many Unix-like systems, it may not be
+    // available in some systems. Please report if you encounter such a system.
+    unsafe { libc::ioctl(raw_fd, libc::TIOCSCTTY as _, 0 as c_int) };
+
+    if tcgetpgrp(raw_fd) == Ok(getpgrp()) {
+        Ok(())
+    } else {
+        Err(nix::Error::ENOTSUP)
+    }
+}

yash/tests/scripted_test.rs

@@ -19,29 +19,43 @@
 //! examines the results. Test cases are written in script files named with the
 //! `-p.sh` or `-y.sh` suffix.
 
+use pty::run_with_pty;
+use std::os::unix::process::CommandExt as _;
 use std::path::Path;
 use std::process::Command;
 use std::process::Stdio;
 
+mod pty;
+
 const BIN: &str = env!("CARGO_BIN_EXE_yash");
 const TMPDIR: &str = env!("CARGO_TARGET_TMPDIR");
 
-fn run(name: &str) {
+/// Runs a test subject.
+///
+/// You would normally not use this function directly. Instead, use one of the
+/// [`run`] or [`run_with_pty`] functions.
+unsafe fn run_with_preexec<F>(name: &str, pre_exec: F)
+where
+    F: FnMut() -> std::io::Result<()> + Send + Sync + 'static,
+{
     // TODO Reset signal blocking mask
 
     let mut log_file = Path::new(TMPDIR).join(name);
     log_file.set_extension("log");
 
-    let result = Command::new("sh")
+    let mut command = Command::new("sh");
+    command
         .env("TMPDIR", TMPDIR)
         .current_dir("tests/scripted_test")
         .stdin(Stdio::null())
         .arg("./run-test.sh")
         .arg(BIN)
         .arg(name)
-        .arg(&log_file)
-        .output()
-        .unwrap();
+        .arg(&log_file);
+    unsafe {
+        command.pre_exec(pre_exec);
+    }
+    let result = command.output().unwrap();
     assert!(result.status.success(), "{:?}", result);
 
     // The `run-test.sh` script returns a successful exit status even if there
@@ -51,6 +65,14 @@ fn run(name: &str) {
     assert!(!log.contains("FAILED"), "{}", log);
 }
 
+/// Runs a test subject.
+///
+/// This function runs the test subject in the current session. To run it in a
+/// separate session, use [`run_with_pty`].
+fn run(name: &str) {
+    unsafe { run_with_preexec(name, || Ok(())) }
+}
+
 #[test]
 fn alias() {
     run("alias-p.sh")
@@ -237,6 +259,11 @@ fn until_loop() {
     run("until-p.sh")
 }
 
+#[test]
+fn wait_builtin() {
+    run_with_pty("wait-p.sh")
+}
+
 #[test]
 fn while_loop() {
     run("while-p.sh")

yash/tests/scripted_test/wait-p.sh

@@ -0,0 +1,122 @@
+# wait-p.sh: test of the wait built-in for any POSIX-compliant shell
+
+posix="true"
+
+test_oE 'waiting for all jobs (+m)'
+echo a > a& echo b > b& echo c > c& exit 1&
+wait
+cat a b c
+__IN__
+a
+b
+c
+__OUT__
+
+test_OE -e 11 'waiting for specific single job (+m)'
+exit 11&
+wait $!
+__IN__
+
+test_OE -e 1 'waiting for specific many jobs (+m)'
+exit 1& p1=$!
+exit 2& p2=$!
+exit 3& p3=$!
+wait $p3 $p2 $p1
+__IN__
+
+test_OE -e 127 'waiting for unknown job (+m)'
+exit 1&
+wait $! $(($!+1))
+__IN__
+
+test_OE -e 127 'jobs are not inherited to subshells (+m, -s)'
+exit 1&
+p=$!
+(wait $p)
+__IN__
+
+test_OE -e 127 'jobs are not inherited to subshells (+m, -c)' \
+    -c 'exit 1& p=$!; (wait $p)'
+__IN__
+
+test_OE -e 1 'jobs are not propagated from subshells (+m)'
+exit 1&
+(exit 2&)
+wait $!
+__IN__
+
+test_oE 'waiting for all jobs (-m)' -m
+echo a > a& echo b > b& echo c > c& exit 1&
+wait
+cat a b c
+__IN__
+a
+b
+c
+__OUT__
+
+test_OE -e 11 'waiting for specific single job (-m)' -m
+exit 11&
+wait $!
+__IN__
+
+test_OE -e 1 'waiting for specific many jobs (-m)' -m
+exit 1& p1=$!
+exit 2& p2=$!
+exit 3& p3=$!
+wait $p3 $p2 $p1
+__IN__
+
+test_OE -e 127 'waiting for unknown job (-m)' -m
+exit 1&
+wait $! $(($!+1))
+__IN__
+
+test_oE -e 11 'specifying job ID' -m
+cat /dev/null&
+echo 1&
+exit 11&
+wait %echo %exit
+__IN__
+1
+__OUT__
+
+test_OE -e 127 'jobs are not inherited to subshells (-m, -s)' -m
+exit 1&
+p=$!
+(wait $p)
+__IN__
+
+test_OE -e 127 'jobs are not inherited to subshells (+m, -c)' \
+    -cm 'exit 1& p=$!; (wait $p)'
+__IN__
+
+test_OE -e 1 'jobs are not propagated from subshells (-m)' -m
+exit 1&
+(exit 2&)
+wait $!
+__IN__
+
+: TODO Needs the kill built-in <<\__OUT__
+test_oE 'trap interrupts wait' -m
+interrupted=false
+trap 'interrupted=true' USR1
+(
+    set +m
+    trap 'echo received USR2; exit' USR2
+    while kill -s USR1 $$; do sleep 1; done # loop until signaled
+)&
+wait $!
+status=$?
+echo interrupted=$interrupted $((status > 128))
+kill -l $status
+# Now, the background job should be still running.
+kill -s USR2 %
+wait $!
+echo waited $?
+__IN__
+interrupted=true 1
+USR1
+received USR2
+waited 0
+__OUT__