Move the signal related kqueue filters to kern_event.c.

Since proc and signal filters share the same klist it makes sense
to keep them together.
OK mvs@

1 files changed, 60 insertions, 1 deletions

diff --git a/sys/kern/kern_event.c b/sys/kern/kern_event.c
index 7e3ae6eae3a..e2c99fe1e78 100644
--- a/sys/kern/kern_event.c
+++ b/sys/kern/kern_event.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_event.c,v 1.198 2023/08/20 15:13:43 visa Exp $	*/
+/*	$OpenBSD: kern_event.c,v 1.199 2024/07/29 12:42:53 claudio Exp $	*/
 
 /*-
  * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
@@ -124,6 +124,9 @@ int	filt_kqueue_common(struct knote *kn, struct kqueue *kq);
 int	filt_procattach(struct knote *kn);
 void	filt_procdetach(struct knote *kn);
 int	filt_proc(struct knote *kn, long hint);
+int	filt_sigattach(struct knote *kn);
+void	filt_sigdetach(struct knote *kn);
+int	filt_signal(struct knote *kn, long hint);
 int	filt_fileattach(struct knote *kn);
 void	filt_timerexpire(void *knx);
 int	filt_timerattach(struct knote *kn);
@@ -148,6 +151,13 @@ const struct filterops proc_filtops = {
 	.f_event	= filt_proc,
 };
 
+const struct filterops sig_filtops = {
+	.f_flags	= 0,
+	.f_attach	= filt_sigattach,
+	.f_detach	= filt_sigdetach,
+	.f_event	= filt_signal,
+};
+
 const struct filterops file_filtops = {
 	.f_flags	= FILTEROP_ISFD | FILTEROP_MPSAFE,
 	.f_attach	= filt_fileattach,
@@ -450,6 +460,55 @@ filt_proc(struct knote *kn, long hint)
 	return (kn->kn_fflags != 0);
 }
 
+/*
+ * signal knotes are shared with proc knotes, so we apply a mask to
+ * the hint in order to differentiate them from process hints.  This
+ * could be avoided by using a signal-specific knote list, but probably
+ * isn't worth the trouble.
+ */
+int
+filt_sigattach(struct knote *kn)
+{
+	struct process *pr = curproc->p_p;
+	int s;
+
+	if (kn->kn_id >= NSIG)
+		return EINVAL;
+
+	kn->kn_ptr.p_process = pr;
+	kn->kn_flags |= EV_CLEAR;		/* automatically set */
+
+	s = splhigh();
+	klist_insert_locked(&pr->ps_klist, kn);
+	splx(s);
+
+	return (0);
+}
+
+void
+filt_sigdetach(struct knote *kn)
+{
+	struct process *pr = kn->kn_ptr.p_process;
+	int s;
+
+	s = splhigh();
+	klist_remove_locked(&pr->ps_klist, kn);
+	splx(s);
+}
+
+int
+filt_signal(struct knote *kn, long hint)
+{
+
+	if (hint & NOTE_SIGNAL) {
+		hint &= ~NOTE_SIGNAL;
+
+		if (kn->kn_id == hint)
+			kn->kn_data++;
+	}
+	return (kn->kn_data != 0);
+}
+
 #define NOTE_TIMER_UNITMASK \
 	(NOTE_SECONDS|NOTE_MSECONDS|NOTE_USECONDS|NOTE_NSECONDS)