From: robert <robert@openbsd.org>
Date: Sat, 13 Jan 2018 12:58:40 +0000 (+0000)
Subject: introduce a filter called EVFILT_DEVICE that can be used to notify
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=586ac5a17b495f9217afcad55bf601907d19d47c;p=openbsd

introduce a filter called EVFILT_DEVICE that can be used to notify
listeners of device state changes.
currently only supports NOTE_CHANGE that will be used by drm(4)

ok kettenis@
---

diff --git a/lib/libc/sys/kqueue.2 b/lib/libc/sys/kqueue.2
index 7dbd3a55c9b..41fbc23db6f 100644
--- a/lib/libc/sys/kqueue.2
+++ b/lib/libc/sys/kqueue.2
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: kqueue.2,v 1.35 2017/07/10 06:38:07 dlg Exp $
+.\"	$OpenBSD: kqueue.2,v 1.36 2018/01/13 12:58:40 robert Exp $
 .\"
 .\" Copyright (c) 2000 Jonathan Lemon
 .\" All rights reserved.
@@ -26,7 +26,7 @@
 .\"
 .\" $FreeBSD: src/lib/libc/sys/kqueue.2,v 1.18 2001/02/14 08:48:35 guido Exp $
 .\"
-.Dd $Mdocdate: July 10 2017 $
+.Dd $Mdocdate: January 13 2018 $
 .Dt KQUEUE 2
 .Os
 .Sh NAME
@@ -451,6 +451,19 @@ contains the number of times the timeout has expired since the last call to
 This filter automatically sets the
 .Dv EV_CLEAR
 flag internally.
+.It Dv EVFILT_DEVICE
+Takes a descriptor as the identifier, and the events to watch for in 
+.Va fflags ,
+and returns when one or more of the reuqested events occur on the
+descriptor. The events to monitor are:
+.Bl -tag -width XXNOTE_CHANGE
+.It Dv NOTE_CHANGE
+A device change event has occured, e.g. an HDMI cable has been plugged in to a port.
+.El
+.Pp
+On return,
+.Va fflags
+contains the events which triggered the filter.
 .El
 .Sh RETURN VALUES
 .Fn kqueue
diff --git a/sys/kern/kern_event.c b/sys/kern/kern_event.c
index 96663208e71..fb9cad360b1 100644
--- a/sys/kern/kern_event.c
+++ b/sys/kern/kern_event.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_event.c,v 1.83 2017/12/18 10:10:53 mpi Exp $	*/
+/*	$OpenBSD: kern_event.c,v 1.84 2018/01/13 12:58:40 robert Exp $	*/
 
 /*-
  * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
@@ -137,6 +137,7 @@ struct filterops *sysfilt_ops[] = {
 	&proc_filtops,			/* EVFILT_PROC */
 	&sig_filtops,			/* EVFILT_SIGNAL */
 	&timer_filtops,			/* EVFILT_TIMER */
+	&file_filtops,			/* EVFILT_DEVICE */
 };
 
 void KQREF(struct kqueue *);
diff --git a/sys/sys/event.h b/sys/sys/event.h
index c3b2b285bfc..e29c1128975 100644
--- a/sys/sys/event.h
+++ b/sys/sys/event.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: event.h,v 1.29 2017/12/21 21:04:38 millert Exp $	*/
+/*	$OpenBSD: event.h,v 1.30 2018/01/13 12:58:40 robert Exp $	*/
 
 /*-
  * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
@@ -38,8 +38,9 @@
 #define EVFILT_PROC		(-5)	/* attached to struct process */
 #define EVFILT_SIGNAL		(-6)	/* attached to struct process */
 #define EVFILT_TIMER		(-7)	/* timers */
+#define EVFILT_DEVICE		(-8)	/* devices */
 
-#define EVFILT_SYSCOUNT		7
+#define EVFILT_SYSCOUNT		8
 
 #define EV_SET(kevp_, a, b, c, d, e, f) do {	\
 	struct kevent *kevp = (kevp_);		\
@@ -111,6 +112,9 @@ struct kevent {
 #define	NOTE_TRACKERR	0x00000002		/* could not track child */
 #define	NOTE_CHILD	0x00000004		/* am a child process */
 
+/* data/hint flags for EVFILT_DEVICE, shared with userspace */
+#define NOTE_CHANGE	0x00000001		/* device change event */
+
 /*
  * This is currently visible to userland to work around broken
  * programs which pull in <sys/proc.h> or <sys/selinfo.h>.