Vendor dependencies

Let's see how I like this workflow.

vendor/signal-hook/tests/shutdown.rs

@@ -0,0 +1,81 @@
+//! Tests for the shutdown.
+//!
+//! The tests work like this:
+//!
+//! * The register an alarm, to fail if anything takes too long (which is very much possible here).
+//! * A fork is done, with the child registering a signal with a NOP and cleanup operation (one or
+//!   the other).
+//! * The child puts some kind of infinite loop or sleep inside itself, so it never actually
+//!   terminates on the first, but would terminate after the signal.
+
+#![cfg(not(windows))] // Forks don't work on Windows, but windows has the same implementation.
+
+use std::io::Error;
+use std::ptr;
+use std::sync::atomic::AtomicBool;
+use std::sync::Arc;
+use std::thread;
+use std::time::Duration;
+
+use signal_hook::consts::signal::*;
+use signal_hook::flag;
+use signal_hook::low_level;
+
+fn do_test<C: FnOnce()>(child: C) {
+    unsafe {
+        libc::alarm(10); // Time out the test after 10 seconds and get it killed.
+        match libc::fork() {
+            -1 => panic!("Fork failed: {}", Error::last_os_error()),
+            0 => {
+                child();
+                loop {
+                    thread::sleep(Duration::from_secs(1));
+                }
+            }
+            pid => {
+                // Give the child some time to register signals and stuff
+                // We could actually signal that the child is ready by it eg. closing STDOUT, but
+                // this is just a test so we don't really bother.
+                thread::sleep(Duration::from_millis(250));
+                libc::kill(pid, libc::SIGTERM);
+                // Wait a small bit to make sure the signal got delivered.
+                thread::sleep(Duration::from_millis(50));
+                // The child is still running, because the first signal got "handled" by being
+                // ignored.
+                let terminated = libc::waitpid(pid, ptr::null_mut(), libc::WNOHANG);
+                assert_eq!(0, terminated, "Process {} terminated prematurely", pid);
+                // But it terminates on the second attempt (we do block on wait here).
+                libc::kill(pid, libc::SIGTERM);
+                let terminated = libc::waitpid(pid, ptr::null_mut(), 0);
+                assert_eq!(pid, terminated);
+            }
+        }
+    }
+}
+
+/// Use automatic cleanup inside the signal handler to get rid of old signals, the aggressive way.
+#[test]
+fn cleanup_inside_signal() {
+    fn hook() {
+        // Make sure we have some signal handler, not the default.
+        unsafe { low_level::register(SIGTERM, || ()).unwrap() };
+        let shutdown_cond = Arc::new(AtomicBool::new(false));
+        // „disarmed“ shutdown
+        flag::register_conditional_shutdown(SIGTERM, 0, Arc::clone(&shutdown_cond)).unwrap();
+        // But arm at the first SIGTERM
+        flag::register(SIGTERM, shutdown_cond).unwrap();
+    }
+    do_test(hook);
+}
+
+/// Manually remove the signal handler just after receiving the signal but before going into an
+/// infinite loop.
+#[test]
+fn cleanup_after_signal() {
+    fn hook() {
+        let mut signals = signal_hook::iterator::Signals::new(&[libc::SIGTERM]).unwrap();
+        assert_eq!(Some(SIGTERM), signals.into_iter().next());
+        flag::register_conditional_shutdown(SIGTERM, 0, Arc::new(AtomicBool::new(true))).unwrap();
+    }
+    do_test(hook);
+}