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. This is a preparation step towards making those filters
MPSAFE.

-- 
:wq Claudio

Index: kern/kern_event.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_event.c,v
diff -u -p -r1.198 kern_event.c
--- kern/kern_event.c	20 Aug 2023 15:13:43 -0000	1.198
+++ kern/kern_event.c	26 Jul 2024 10:14:46 -0000
@@ -124,6 +124,9 @@ int	filt_kqueue_common(struct knote *kn,
 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,
@@ -448,6 +458,55 @@ 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 \
Index: kern/kern_sig.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_sig.c,v
diff -u -p -r1.334 kern_sig.c
--- kern/kern_sig.c	24 Jul 2024 15:31:08 -0000	1.334
+++ kern/kern_sig.c	26 Jul 2024 10:14:46 -0000
@@ -70,17 +70,6 @@
 
 int nosuidcoredump = 1;
 
-int	filt_sigattach(struct knote *kn);
-void	filt_sigdetach(struct knote *kn);
-int	filt_signal(struct knote *kn, long hint);
-
-const struct filterops sig_filtops = {
-	.f_flags	= 0,
-	.f_attach	= filt_sigattach,
-	.f_detach	= filt_sigdetach,
-	.f_event	= filt_signal,
-};
-
 /*
  * The array below categorizes the signals and their default actions.
  */
@@ -1972,55 +1961,6 @@ initsiginfo(siginfo_t *si, int sig, u_lo
 			break;
 		}
 	}
-}
-
-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);
-}
-
-/*
- * 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_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);
 }
 
 void
Index: sys/event.h
===================================================================
RCS file: /cvs/src/sys/sys/event.h,v
diff -u -p -r1.71 event.h
--- sys/event.h	20 Aug 2023 15:13:43 -0000	1.71
+++ sys/event.h	26 Jul 2024 10:14:46 -0000
@@ -285,7 +285,6 @@ struct proc;
 struct rwlock;
 struct timespec;
 
-extern const struct filterops sig_filtops;
 extern const struct filterops dead_filtops;
 
 extern void	kqpoll_init(unsigned int);