1 files changed, 74 insertions, 24 deletions

diff --git a/src/signal/unix.rs b/src/signal/unix.rs
index 86ea9a9..0e1329e 100644
--- a/src/signal/unix.rs
+++ b/src/signal/unix.rs
@@ -6,6 +6,8 @@
 #![cfg(unix)]
 #![cfg_attr(docsrs, doc(cfg(all(unix, feature = "signal"))))]
 
+use crate::runtime::scheduler;
+use crate::runtime::signal::Handle;
 use crate::signal::registry::{globals, EventId, EventInfo, Globals, Init, Storage};
 use crate::signal::RxFuture;
 use crate::sync::watch;
@@ -17,18 +19,19 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Once;
 use std::task::{Context, Poll};
 
-pub(crate) mod driver;
-use self::driver::Handle;
-
 pub(crate) type OsStorage = Vec<SignalInfo>;
 
-// Number of different unix signals
-// (FreeBSD has 33)
-const SIGNUM: usize = 33;
-
 impl Init for OsStorage {
     fn init() -> Self {
-        (0..SIGNUM).map(|_| SignalInfo::default()).collect()
+        // There are reliable signals ranging from 1 to 33 available on every Unix platform.
+        #[cfg(not(target_os = "linux"))]
+        let possible = 0..=33;
+
+        // On Linux, there are additional real-time signals available.
+        #[cfg(target_os = "linux")]
+        let possible = 0..=libc::SIGRTMAX();
+
+        possible.map(|_| SignalInfo::default()).collect()
     }
 }
 
@@ -48,7 +51,7 @@ impl Storage for OsStorage {
 #[derive(Debug)]
 pub(crate) struct OsExtraData {
     sender: UnixStream,
-    receiver: UnixStream,
+    pub(crate) receiver: UnixStream,
 }
 
 impl Init for OsExtraData {
@@ -60,7 +63,7 @@ impl Init for OsExtraData {
 }
 
 /// Represents the specific kind of signal to listen for.
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
 pub struct SignalKind(libc::c_int);
 
 impl SignalKind {
@@ -80,15 +83,26 @@ impl SignalKind {
     // unlikely to change to other types, but technically libc can change this
     // in the future minor version.
     // See https://github.com/tokio-rs/tokio/issues/3767 for more.
-    pub fn from_raw(signum: std::os::raw::c_int) -> Self {
+    pub const fn from_raw(signum: std::os::raw::c_int) -> Self {
         Self(signum as libc::c_int)
     }
 
+    /// Get the signal's numeric value.
+    ///
+    /// ```rust
+    /// # use tokio::signal::unix::SignalKind;
+    /// let kind = SignalKind::interrupt();
+    /// assert_eq!(kind.as_raw_value(), libc::SIGINT);
+    /// ```
+    pub const fn as_raw_value(&self) -> std::os::raw::c_int {
+        self.0
+    }
+
     /// Represents the SIGALRM signal.
     ///
     /// On Unix systems this signal is sent when a real-time timer has expired.
     /// By default, the process is terminated by this signal.
-    pub fn alarm() -> Self {
+    pub const fn alarm() -> Self {
         Self(libc::SIGALRM)
     }
 
@@ -96,7 +110,7 @@ impl SignalKind {
     ///
     /// On Unix systems this signal is sent when the status of a child process
     /// has changed. By default, this signal is ignored.
-    pub fn child() -> Self {
+    pub const fn child() -> Self {
         Self(libc::SIGCHLD)
     }
 
@@ -104,7 +118,7 @@ impl SignalKind {
     ///
     /// On Unix systems this signal is sent when the terminal is disconnected.
     /// By default, the process is terminated by this signal.
-    pub fn hangup() -> Self {
+    pub const fn hangup() -> Self {
         Self(libc::SIGHUP)
     }
 
@@ -119,7 +133,7 @@ impl SignalKind {
         target_os = "netbsd",
         target_os = "openbsd"
     ))]
-    pub fn info() -> Self {
+    pub const fn info() -> Self {
         Self(libc::SIGINFO)
     }
 
@@ -127,7 +141,7 @@ impl SignalKind {
     ///
     /// On Unix systems this signal is sent to interrupt a program.
     /// By default, the process is terminated by this signal.
-    pub fn interrupt() -> Self {
+    pub const fn interrupt() -> Self {
         Self(libc::SIGINT)
     }
 
@@ -135,7 +149,7 @@ impl SignalKind {
     ///
     /// On Unix systems this signal is sent when I/O operations are possible
     /// on some file descriptor. By default, this signal is ignored.
-    pub fn io() -> Self {
+    pub const fn io() -> Self {
         Self(libc::SIGIO)
     }
 
@@ -144,7 +158,7 @@ impl SignalKind {
     /// On Unix systems this signal is sent when the process attempts to write
     /// to a pipe which has no reader. By default, the process is terminated by
     /// this signal.
-    pub fn pipe() -> Self {
+    pub const fn pipe() -> Self {
         Self(libc::SIGPIPE)
     }
 
@@ -153,7 +167,7 @@ impl SignalKind {
     /// On Unix systems this signal is sent to issue a shutdown of the
     /// process, after which the OS will dump the process core.
     /// By default, the process is terminated by this signal.
-    pub fn quit() -> Self {
+    pub const fn quit() -> Self {
         Self(libc::SIGQUIT)
     }
 
@@ -161,7 +175,7 @@ impl SignalKind {
     ///
     /// On Unix systems this signal is sent to issue a shutdown of the
     /// process. By default, the process is terminated by this signal.
-    pub fn terminate() -> Self {
+    pub const fn terminate() -> Self {
         Self(libc::SIGTERM)
     }
 
@@ -169,7 +183,7 @@ impl SignalKind {
     ///
     /// On Unix systems this is a user defined signal.
     /// By default, the process is terminated by this signal.
-    pub fn user_defined1() -> Self {
+    pub const fn user_defined1() -> Self {
         Self(libc::SIGUSR1)
     }
 
@@ -177,7 +191,7 @@ impl SignalKind {
     ///
     /// On Unix systems this is a user defined signal.
     /// By default, the process is terminated by this signal.
-    pub fn user_defined2() -> Self {
+    pub const fn user_defined2() -> Self {
         Self(libc::SIGUSR2)
     }
 
@@ -185,11 +199,23 @@ impl SignalKind {
     ///
     /// On Unix systems this signal is sent when the terminal window is resized.
     /// By default, this signal is ignored.
-    pub fn window_change() -> Self {
+    pub const fn window_change() -> Self {
         Self(libc::SIGWINCH)
     }
 }
 
+impl From<std::os::raw::c_int> for SignalKind {
+    fn from(signum: std::os::raw::c_int) -> Self {
+        Self::from_raw(signum as libc::c_int)
+    }
+}
+
+impl From<SignalKind> for std::os::raw::c_int {
+    fn from(kind: SignalKind) -> Self {
+        kind.as_raw_value()
+    }
+}
+
 pub(crate) struct SignalInfo {
     event_info: EventInfo,
     init: Once,
@@ -357,8 +383,15 @@ pub struct Signal {
 /// * If the previous initialization of this specific signal failed.
 /// * If the signal is one of
 ///   [`signal_hook::FORBIDDEN`](fn@signal_hook_registry::register#panics)
+///
+/// # Panics
+///
+/// This function panics if there is no current reactor set, or if the `rt`
+/// feature flag is not enabled.
+#[track_caller]
 pub fn signal(kind: SignalKind) -> io::Result<Signal> {
-    let rx = signal_with_handle(kind, &Handle::current())?;
+    let handle = scheduler::Handle::current();
+    let rx = signal_with_handle(kind, handle.driver().signal())?;
 
     Ok(Signal {
         inner: RxFuture::new(rx),
@@ -380,6 +413,12 @@ impl Signal {
     ///
     /// `None` is returned if no more events can be received by this stream.
     ///
+    /// # Cancel safety
+    ///
+    /// This method is cancel safe. If you use it as the event in a
+    /// [`tokio::select!`](crate::select) statement and some other branch
+    /// completes first, then it is guaranteed that no signal is lost.
+    ///
     /// # Examples
     ///
     /// Wait for SIGHUP
@@ -474,4 +513,15 @@ mod tests {
         )
         .unwrap_err();
     }
+
+    #[test]
+    fn from_c_int() {
+        assert_eq!(SignalKind::from(2), SignalKind::interrupt());
+    }
+
+    #[test]
+    fn into_c_int() {
+        let value: std::os::raw::c_int = SignalKind::interrupt().into();
+        assert_eq!(value, libc::SIGINT as _);
+    }
 }