signals: Add support for Windows

CHANGELOG.md

@@ -27,6 +27,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   This is fixed by using `winsplit` on Windows instead.
 - On Windows, zombie `git-upload-pack` processes are now prevented by using the
   "Job" API of the operating system to group child processes and their children.
+- On Windows, signal handling was not supported. The `radicle-node` executable
+  will now respect signal handling on Windows.
 
 ## Deprecations
 

Cargo.lock

@@ -3151,6 +3151,7 @@ dependencies = [
  "crossbeam-channel",
  "libc",
  "signals_receipts",
+ "windows 0.62.2",
 ]
 
 [[package]]

Cargo.toml

@@ -70,6 +70,7 @@ sqlite = "0.32.0"
 tempfile = "3.3.0"
 thiserror = { version = "2", default-features = false }
 uds_windows = "1.1.0"
+windows = "0.62"
 winpipe = "0.1.1"
 winsplit = "0.1.0"
 zeroize = "1.5.7"

crates/radicle-node/src/main.rs

@@ -13,7 +13,6 @@ use radicle::profile;
 use radicle_node::crypto::ssh::keystore::{Keystore, MemorySigner};
 use radicle_node::fingerprint::{Fingerprint, FingerprintVerification};
 use radicle_node::{Runtime, VERSION};
-#[cfg(unix)]
 use radicle_signals as signals;
 
 const HELP_MSG: &str = r#"
@@ -320,20 +319,12 @@ fn execute(options: Options) -> Result<(), ExecutionError> {
         log::warn!(target: "node", "Unable to set process open file limit: {e}");
     }
 
-    #[cfg(unix)]
     let signals = {
         let (notify, signals) = chan::bounded(1);
         signals::install(notify)?;
         signals
     };
 
-    #[cfg(windows)]
-    let signals = {
-        let (_, signals) = chan::bounded(1);
-        log::info!(target: "node", "No signal handlers were installed, because this is not available on Windows.");
-        signals
-    };
-
     if options.force {
         log::debug!(target: "node", "Removing existing control socket..");
         std::fs::remove_file(home.socket()).ok();

crates/radicle-node/src/runtime.rs

@@ -287,7 +287,6 @@ impl Runtime {
             || control::listen(listener, handle)
         });
 
-        #[cfg(unix)]
         let _signals = thread::spawn(&self.id, "signals", move || loop {
             use radicle::node::Handle as _;
 

crates/radicle-signals/Cargo.toml

@@ -8,7 +8,16 @@ edition.workspace = true
 version = "0.11.0"
 rust-version.workspace = true
 
-[target.'cfg(unix)'.dependencies]
+[dependencies]
 crossbeam-channel = { workspace = true }
+
+[target.'cfg(unix)'.dependencies]
 libc = { workspace = true }
 signals_receipts = { version = "0.2.0", features = ["channel_notify_facility"] }
+
+[target.'cfg(windows)'.dependencies.windows]
+workspace = true
+features = [
+    "Win32_Foundation",
+    "Win32_System_Console",
+]

crates/radicle-signals/src/lib.rs

@@ -1,9 +1,17 @@
+use std::io;
+
 #[cfg(unix)]
 mod unix;
 
 #[cfg(unix)]
 pub use unix::*;
 
+#[cfg(windows)]
+mod windows;
+
+#[cfg(windows)]
+pub use windows::*;
+
 /// Operating system signal.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub enum Signal {
@@ -16,3 +24,12 @@ pub enum Signal {
     /// `SIGWINCH`.
     WindowChanged,
 }
+
+/// Return an error indicating that signal handling is already installed.
+#[inline(always)]
+fn already_installed() -> io::Error {
+    io::Error::new(
+        io::ErrorKind::AlreadyExists,
+        "signal handling is already installed",
+    )
+}

crates/radicle-signals/src/unix.rs

@@ -57,10 +57,7 @@ pub fn install(notify: chan::Sender<Signal>) -> io::Result<()> {
     }
 
     SignalsChannel::install_with_outside_channel(ChanSender(notify)).map_err(|e| match e {
-        InstallError::AlreadyInstalled { unused_notify: _ } => io::Error::new(
-            io::ErrorKind::AlreadyExists,
-            "signal handling is already installed",
-        ),
+        InstallError::AlreadyInstalled { unused_notify: _ } => already_installed(),
         _ => io::Error::other(e), // The error type is non-exhaustive.
     })
 }

crates/radicle-signals/src/windows.rs

@@ -0,0 +1,50 @@
+use std::io;
+use std::sync::OnceLock;
+
+use crossbeam_channel as chan;
+
+use ::windows::core::BOOL;
+use ::windows::Win32::System::Console::{
+    SetConsoleCtrlHandler, CTRL_BREAK_EVENT, CTRL_CLOSE_EVENT, CTRL_C_EVENT, CTRL_LOGOFF_EVENT,
+    CTRL_SHUTDOWN_EVENT,
+};
+
+use crate::{already_installed, Signal};
+
+static NOTIFY: OnceLock<chan::Sender<Signal>> = OnceLock::new();
+
+/// Callback function, called by the system when a control signal is to be received.
+/// See <https://learn.microsoft.com/en-us/windows/console/handlerroutine>.
+unsafe extern "system" fn handler(ctrltype: u32) -> BOOL {
+    match ctrltype {
+        CTRL_C_EVENT | CTRL_BREAK_EVENT | CTRL_CLOSE_EVENT | CTRL_SHUTDOWN_EVENT => {
+            if let Some(notify) = NOTIFY.get() {
+                if notify.send(Signal::Terminate).is_ok() {
+                    return true.into();
+                }
+            } else {
+                // Do nothing, since we do not have a channel to send notifications to.
+            }
+        }
+        CTRL_LOGOFF_EVENT => {
+            // Do nothing, since we do not know which user is logging off.
+        }
+        _ => {
+            // Do nothing, since we received an unknown control signal.
+        }
+    }
+
+    false.into()
+}
+
+/// Install global signal handlers, with notifications sent to the given
+/// `notify` channel.
+pub fn install(notify: chan::Sender<Signal>) -> io::Result<()> {
+    if let Err(_) = NOTIFY.set(notify) {
+        return Err(already_installed());
+    }
+
+    // SAFETY: Our handler function is sane.
+    let result = unsafe { SetConsoleCtrlHandler(Some(handler), true) };
+    result.map_err(|_| io::Error::last_os_error())
+}

crates/radicle-windows/Cargo.toml

@@ -12,7 +12,7 @@ rust-version.workspace = true
 thiserror = { workspace = true }
 
 [target.'cfg(windows)'.dependencies.windows]
-version = "0.62"
+workspace = true
 features = [
     "Win32_Foundation",
     "Win32_Security",