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Re: kern/55663: Support for EVFILT_USER in kqueue(2)
I attached a new patch below with changes per Martin's recommendations.
Please let me know if someone can review that.
diff --git a/share/man/man9/kfilter_register.9
b/share/man/man9/kfilter_register.9
index 43ba379b8c40..f405819140aa 100644
--- a/share/man/man9/kfilter_register.9
+++ b/share/man/man9/kfilter_register.9
@@ -97,6 +97,7 @@ struct filterops {
/* called when knote is DELETEd */
int (*f_event)(struct knote *kn, long hint);
/* called when event is triggered */
+ void (*f_touch)(struct knote *kn, struct kevent *kev, long hint);
};
.Ed
.Pp
diff --git a/sys/arch/arm/xscale/pxa2x0_apm.c
b/sys/arch/arm/xscale/pxa2x0_apm.c
index f27b56901f82..869e392fb9f1 100644
--- a/sys/arch/arm/xscale/pxa2x0_apm.c
+++ b/sys/arch/arm/xscale/pxa2x0_apm.c
@@ -104,8 +104,12 @@ void filt_apmrdetach(struct knote *kn);
int filt_apmread(struct knote *kn, long hint);
int apmkqfilter(dev_t dev, struct knote *kn);
-struct filterops apmread_filtops =
- { 1, NULL, filt_apmrdetach, filt_apmread};
+struct filterops apmread_filtops = {
+ .f_isfd = 1,
+ .f_attach = NULL,
+ .f_detach = filt_apmrdetach,
+ .f_event = filt_apmread,
+};
#endif
/*
diff --git a/sys/arch/macppc/dev/apm.c b/sys/arch/macppc/dev/apm.c
index c96f2aac2b2d..ae8b15cffe5b 100644
--- a/sys/arch/macppc/dev/apm.c
+++ b/sys/arch/macppc/dev/apm.c
@@ -431,8 +431,12 @@ filt_apmread(struct knote *kn, long hint)
return (kn->kn_data > 0);
}
-static struct filterops apmread_filtops =
- { 1, NULL, filt_apmrdetach, filt_apmread};
+static struct filterops apmread_filtops = {
+ .f_isfd = 1,
+ .f_attach = NULL,
+ .f_detach = filt_apmrdetach,
+ .f_event = filt_apmread,
+};
int
apmkqfilter(dev_t dev, struct knote *kn)
diff --git a/sys/arch/mips/ralink/ralink_gpio.c
b/sys/arch/mips/ralink/ralink_gpio.c
index 127acd6b5991..a073029ad698 100644
--- a/sys/arch/mips/ralink/ralink_gpio.c
+++ b/sys/arch/mips/ralink/ralink_gpio.c
@@ -495,10 +495,10 @@ static int gpio_event_app_user_event(struct knote
*, long);
static struct klist knotes;
static int app_filter_id;
static struct filterops app_fops = {
- 0,
- gpio_event_app_user_attach,
- gpio_event_app_user_detach,
- gpio_event_app_user_event
+ .f_isfd = 0,
+ .f_attach = gpio_event_app_user_attach,
+ .f_detach = gpio_event_app_user_detach,
+ .f_event = gpio_event_app_user_event,
};
static struct callout led_tick_callout;
static int gpio_driver_blink_leds = 1;
diff --git a/sys/kern/kern_event.c b/sys/kern/kern_event.c
index 6ed5bec32e52..f8bb3968e84a 100644
--- a/sys/kern/kern_event.c
+++ b/sys/kern/kern_event.c
@@ -31,6 +31,7 @@
/*-
* Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon%FreeBSD.org@localhost>
+ * Copyright (c) 2009 Apple, Inc
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -109,6 +110,10 @@ static int filt_timer(struct knote *, long hint);
static int filt_fsattach(struct knote *kn);
static void filt_fsdetach(struct knote *kn);
static int filt_fs(struct knote *kn, long hint);
+static int filt_userattach(struct knote *);
+static void filt_userdetach(struct knote *);
+static int filt_user(struct knote *, long hint);
+static void filt_usertouch(struct knote *, struct kevent *, long type);
static const struct fileops kqueueops = {
.fo_name = "kqueue",
@@ -128,6 +133,7 @@ static const struct filterops kqread_filtops = {
.f_attach = NULL,
.f_detach = filt_kqdetach,
.f_event = filt_kqueue,
+ .f_touch = NULL,
};
static const struct filterops proc_filtops = {
@@ -135,6 +141,7 @@ static const struct filterops proc_filtops = {
.f_attach = filt_procattach,
.f_detach = filt_procdetach,
.f_event = filt_proc,
+ .f_touch = NULL,
};
static const struct filterops file_filtops = {
@@ -142,6 +149,7 @@ static const struct filterops file_filtops = {
.f_attach = filt_fileattach,
.f_detach = NULL,
.f_event = NULL,
+ .f_touch = NULL,
};
static const struct filterops timer_filtops = {
@@ -149,6 +157,7 @@ static const struct filterops timer_filtops = {
.f_attach = filt_timerattach,
.f_detach = filt_timerdetach,
.f_event = filt_timer,
+ .f_touch = NULL,
};
static const struct filterops fs_filtops = {
@@ -156,6 +165,15 @@ static const struct filterops fs_filtops = {
.f_attach = filt_fsattach,
.f_detach = filt_fsdetach,
.f_event = filt_fs,
+ .f_touch = NULL,
+};
+
+static const struct filterops user_filtops = {
+ .f_isfd = 0,
+ .f_attach = filt_userattach,
+ .f_detach = filt_userdetach,
+ .f_event = filt_user,
+ .f_touch = filt_usertouch,
};
static u_int kq_ncallouts = 0;
@@ -192,6 +210,7 @@ static struct kfilter sys_kfilters[] = {
{ "EVFILT_SIGNAL", EVFILT_SIGNAL, 0, &sig_filtops, 0 },
{ "EVFILT_TIMER", EVFILT_TIMER, 0, &timer_filtops, 0 },
{ "EVFILT_FS", EVFILT_FS, 0, &fs_filtops, 0 },
+ { "EVFILT_USER", EVFILT_USER, 0, &user_filtops, 0 },
{ NULL, 0, 0, NULL, 0 },
};
@@ -776,6 +795,106 @@ filt_fs(struct knote *kn, long hint)
return rv;
}
+static int
+filt_userattach(struct knote *kn)
+{
+ struct kqueue *kq = kn->kn_kq;
+
+ /*
+ * EVFILT_USER knotes are not attached to anything in the kernel.
+ */
+ mutex_spin_enter(&kq->kq_lock);
+ kn->kn_hook = NULL;
+ if (kn->kn_fflags & NOTE_TRIGGER)
+ kn->kn_hookid = 1;
+ else
+ kn->kn_hookid = 0;
+ mutex_spin_exit(&kq->kq_lock);
+ return (0);
+}
+
+static void
+filt_userdetach(struct knote *kn)
+{
+
+ /*
+ * EVFILT_USER knotes are not attached to anything in the kernel.
+ */
+}
+
+static int
+filt_user(struct knote *kn, long hint)
+{
+ struct kqueue *kq = kn->kn_kq;
+ int hookid;
+
+ mutex_spin_enter(&kq->kq_lock);
+ hookid = kn->kn_hookid;
+ mutex_spin_exit(&kq->kq_lock);
+
+ return hookid;
+}
+
+static void
+filt_usertouch(struct knote *kn, struct kevent *kev, long type)
+{
+ struct kqueue *kq = kn->kn_kq;
+ int ffctrl;
+
+ mutex_spin_enter(&kq->kq_lock);
+ switch (type) {
+ case EVENT_REGISTER:
+ if (kev->fflags & NOTE_TRIGGER)
+ kn->kn_hookid = 1;
+
+ ffctrl = kev->fflags & NOTE_FFCTRLMASK;
+ kev->fflags &= NOTE_FFLAGSMASK;
+ switch (ffctrl) {
+ case NOTE_FFNOP:
+ break;
+
+ case NOTE_FFAND:
+ kn->kn_sfflags &= kev->fflags;
+ break;
+
+ case NOTE_FFOR:
+ kn->kn_sfflags |= kev->fflags;
+ break;
+
+ case NOTE_FFCOPY:
+ kn->kn_sfflags = kev->fflags;
+ break;
+
+ default:
+ /* XXX Return error? */
+ break;
+ }
+ kn->kn_sdata = kev->data;
+ if (kev->flags & EV_CLEAR) {
+ kn->kn_hookid = 0;
+ kn->kn_data = 0;
+ kn->kn_fflags = 0;
+ }
+ break;
+
+ case EVENT_PROCESS:
+ *kev = kn->kn_kevent;
+ kev->fflags = kn->kn_sfflags;
+ kev->data = kn->kn_sdata;
+ if (kn->kn_flags & EV_CLEAR) {
+ kn->kn_hookid = 0;
+ kn->kn_data = 0;
+ kn->kn_fflags = 0;
+ }
+ break;
+
+ default:
+ panic("filt_usertouch() - invalid type (%ld)", type);
+ break;
+ }
+ mutex_spin_exit(&kq->kq_lock);
+}
+
/*
* filt_seltrue:
*
@@ -809,6 +928,7 @@ const struct filterops seltrue_filtops = {
.f_attach = NULL,
.f_detach = filt_seltruedetach,
.f_event = filt_seltrue,
+ .f_touch = NULL,
};
int
@@ -1072,8 +1192,8 @@ kqueue_register(struct kqueue *kq, struct kevent *kev)
/*
* kn now contains the matching knote, or NULL if no match
*/
- if (kev->flags & EV_ADD) {
- if (kn == NULL) {
+ if (kn == NULL) {
+ if (kev->flags & EV_ADD) {
/* create new knote */
kn = newkn;
newkn = NULL;
@@ -1137,41 +1257,51 @@ kqueue_register(struct kqueue *kq, struct kevent
*kev)
goto done;
}
atomic_inc_uint(&kfilter->refcnt);
+ goto done_ev_add;
} else {
- /*
- * The user may change some filter values after the
- * initial EV_ADD, but doing so will not reset any
- * filter which have already been triggered.
- */
- kn->kn_sfflags = kev->fflags;
- kn->kn_sdata = kev->data;
- kn->kn_kevent.udata = kev->udata;
- }
- /*
- * We can get here if we are trying to attach
- * an event to a file descriptor that does not
- * support events, and the attach routine is
- * broken and does not return an error.
- */
- KASSERT(kn->kn_fop != NULL);
- KASSERT(kn->kn_fop->f_event != NULL);
- KERNEL_LOCK(1, NULL); /* XXXSMP */
- rv = (*kn->kn_fop->f_event)(kn, 0);
- KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */
- if (rv)
- knote_activate(kn);
- } else {
- if (kn == NULL) {
+ /* No matching knote and the EV_ADD flag is not set. */
error = ENOENT;
goto doneunlock;
}
- if (kev->flags & EV_DELETE) {
- /* knote_detach() drops fdp->fd_lock */
- knote_detach(kn, fdp, true);
- goto done;
- }
}
+ if (kev->flags & EV_DELETE) {
+ /* knote_detach() drops fdp->fd_lock */
+ knote_detach(kn, fdp, true);
+ goto done;
+ }
+
+ /*
+ * The user may change some filter values after the
+ * initial EV_ADD, but doing so will not reset any
+ * filter which have already been triggered.
+ */
+ kn->kn_kevent.udata = kev->udata;
+ KASSERT(kn->kn_fop != NULL);
+ if (!kn->kn_fop->f_isfd && kn->kn_fop->f_touch != NULL) {
+ KERNEL_LOCK(1, NULL); /* XXXSMP */
+ (*kn->kn_fop->f_touch)(kn, kev, EVENT_REGISTER);
+ KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */
+ } else {
+ kn->kn_sfflags = kev->fflags;
+ kn->kn_sdata = kev->data;
+ }
+
+ /*
+ * We can get here if we are trying to attach
+ * an event to a file descriptor that does not
+ * support events, and the attach routine is
+ * broken and does not return an error.
+ */
+done_ev_add:
+ KASSERT(kn->kn_fop != NULL);
+ KASSERT(kn->kn_fop->f_event != NULL);
+ KERNEL_LOCK(1, NULL); /* XXXSMP */
+ rv = (*kn->kn_fop->f_event)(kn, 0);
+ KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */
+ if (rv)
+ knote_activate(kn);
+
/* disable knote */
if ((kev->flags & EV_DISABLE)) {
mutex_spin_enter(&kq->kq_lock);
@@ -1271,7 +1401,7 @@ kqueue_scan(file_t *fp, size_t maxevents, struct
kevent *ulistp,
struct timespec ats, sleepts;
struct knote *kn, *marker, morker;
size_t count, nkev, nevents;
- int timeout, error, rv;
+ int timeout, error, touch, rv;
filedesc_t *fdp;
fdp = curlwp->l_fd;
@@ -1382,8 +1512,20 @@ kqueue_scan(file_t *fp, size_t maxevents, struct
kevent *ulistp,
continue;
}
}
+ KASSERT(kn->kn_fop != NULL);
+ touch = (!kn->kn_fop->f_isfd &&
+ kn->kn_fop->f_touch != NULL);
/* XXXAD should be got from f_event if !oneshot. */
- *kevp++ = kn->kn_kevent;
+ if (touch) {
+ mutex_spin_exit(&kq->kq_lock);
+ KERNEL_LOCK(1, NULL); /* XXXSMP */
+ (*kn->kn_fop->f_touch)(kn, kevp, EVENT_PROCESS);
+ KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */
+ mutex_spin_enter(&kq->kq_lock);
+ } else {
+ *kevp = kn->kn_kevent;
+ }
+ kevp++;
nkev++;
if (kn->kn_flags & EV_ONESHOT) {
/* delete ONESHOT events after retrieval */
@@ -1396,6 +1538,14 @@ kqueue_scan(file_t *fp, size_t maxevents, struct
kevent *ulistp,
/* clear state after retrieval */
kn->kn_data = 0;
kn->kn_fflags = 0;
+ /*
+ * Manually clear knotes who weren't
+ * 'touch'ed.
+ */
+ if (touch == 0) {
+ kn->kn_data = 0;
+ kn->kn_fflags = 0;
+ }
kn->kn_status &= ~(KN_QUEUED|KN_ACTIVE|KN_BUSY);
} else if (kn->kn_flags & EV_DISPATCH) {
kn->kn_status |= KN_DISABLED;
diff --git a/sys/net/if_tap.c b/sys/net/if_tap.c
index d6505938e6c3..4176a57402c6 100644
--- a/sys/net/if_tap.c
+++ b/sys/net/if_tap.c
@@ -1232,10 +1232,19 @@ tap_dev_poll(int unit, int events, struct lwp *l)
return revents;
}
-static struct filterops tap_read_filterops = { 1, NULL, tap_kqdetach,
- tap_kqread };
-static struct filterops tap_seltrue_filterops = { 1, NULL, tap_kqdetach,
- filt_seltrue };
+static struct filterops tap_read_filterops = {
+ .f_isfd = 1,
+ .f_attach = NULL,
+ .f_detach = tap_kqdetach,
+ .f_event = tap_kqread,
+};
+
+static struct filterops tap_seltrue_filterops = {
+ .f_isfd = 1,
+ .f_attach = NULL,
+ .f_detach = tap_kqdetach,
+ .f_event = filt_seltrue,
+};
static int
tap_cdev_kqfilter(dev_t dev, struct knote *kn)
diff --git a/sys/sys/event.h b/sys/sys/event.h
index dd18e51bb4ce..2473d7b220e3 100644
--- a/sys/sys/event.h
+++ b/sys/sys/event.h
@@ -44,7 +44,8 @@
#define EVFILT_SIGNAL 5U /* attached to struct proc */
#define EVFILT_TIMER 6U /* arbitrary timer (in ms) */
#define EVFILT_FS 7U /* filesystem events */
-#define EVFILT_SYSCOUNT 8U /* number of filters */
+#define EVFILT_USER 8U /* user events */
+#define EVFILT_SYSCOUNT 9U /* number of filters */
struct kevent {
uintptr_t ident; /* identifier for this event */
@@ -90,6 +91,26 @@ _EV_SET(struct kevent *_kevp, uintptr_t _ident,
uint32_t _filter,
#define EV_EOF 0x8000U /* EOF detected */
#define EV_ERROR 0x4000U /* error, data contains errno */
+/*
+ * data/hint flags/masks for EVFILT_USER, shared with userspace
+ *
+ * On input, the top two bits of fflags specifies how the lower twenty four
+ * bits should be applied to the stored value of fflags.
+ *
+ * On output, the top two bits will always be set to NOTE_FFNOP and the
+ * remaining twenty four bits will contain the stored fflags value.
+ */
+#define NOTE_FFNOP 0x00000000U /* ignore input fflags */
+#define NOTE_FFAND 0x40000000U /* AND fflags */
+#define NOTE_FFOR 0x80000000U /* OR fflags */
+#define NOTE_FFCOPY 0xc0000000U /* copy fflags */
+
+#define NOTE_FFCTRLMASK 0xc0000000U /* masks for operations */
+#define NOTE_FFLAGSMASK 0x00ffffffU
+
+#define NOTE_TRIGGER 0x01000000U /* Cause the event to be
+ triggered for output. */
+
/*
* hint flag for in-kernel use - must not equal any existing note
*/
@@ -161,6 +182,16 @@ struct kfilter_mapping {
*/
#define NOTE_SIGNAL 0x08000000U
+/*
+ * Hint values for the optional f_touch event filter. If f_touch is
not set
+ * to NULL and f_isfd is zero the f_touch filter will be called with
the type
+ * argument set to EVENT_REGISTER during a kevent() system call. It is
also
+ * called under the same conditions with the type argument set to
EVENT_PROCESS
+ * when the event has been triggered.
+ */
+#define EVENT_REGISTER 1
+#define EVENT_PROCESS 2
+
/*
* Callback methods for each filter type.
*/
@@ -172,6 +203,7 @@ struct filterops {
/* called when knote is DELETEd */
int (*f_event) (struct knote *, long);
/* called when event is triggered */
+ void (*f_touch) (struct knote *, struct kevent *, long);
};
/*
@@ -196,6 +228,7 @@ struct knote {
const struct filterops *kn_fop;
struct kfilter *kn_kfilter;
void *kn_hook;
+ int kn_hookid;
#define KN_ACTIVE 0x01U /* event has been triggered */
#define KN_QUEUED 0x02U /* event is on queue */
------------------------------------------------------------------------------------------
On 9/17/20 1:30 AM, Martin Husemann wrote:
The following reply was made to PR kern/55663; it has been noted by GNATS.
From: Martin Husemann <martin%duskware.de@localhost>
To: Ruslan Nikolaev <nruslan_devel%yahoo.com@localhost>
Cc: gnats-bugs%netbsd.org@localhost
Subject: Re: kern/55663: Support for EVFILT_USER in kqueue(2)
Date: Thu, 17 Sep 2020 07:25:10 +0200
On Wed, Sep 16, 2020 at 04:09:36PM -0400, Ruslan Nikolaev wrote:
> 1. Skip changes like you have shown, where f_touch is initialized to NULL,
> assuming the default value for unspecified fields (= 0).
>
> 2. Change structs such as { 1, NULL, filt_apmrdetach, filt_apmread}
> to {
> .f_isfd = 1,
> .f_detach = filt_apmrdetach,
> .f_event = filt_apmread,
> }
Yes, exactly!
Martin
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