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freebsd-dev/sys/kern/kern_event.c
David Bright 95c05062ec Allow a EVFILT_TIMER kevent to be updated. 
If a timer is updated (re-added) with a different time period
(specified in the .data field of the kevent), the new time period has
no effect; the timer will not expire until the original time has
elapsed. This violates the documented behavior as the kqueue(2) man
page says (in part) "Re-adding an existing event will modify the
parameters of the original event, and not result in a duplicate
entry."

This modification, adapted from a patch submitted by cem@ to PR214987,
fixes the kqueue system to allow updating a timer entry. The
kevent timer behavior is changed to:

  * When a timer is re-added, update the timer parameters to and
    re-start the timer using the new parameters.
  * Allow updating both active and already expired timers.
  * When the timer has already expired, dequeue any undelivered events
    and clear the count of expirations.

All of these changes address the original PR and also bring the
FreeBSD and macOS kevent timer behaviors into agreement.

A few other changes were made along the way:

  * Update the kqueue(2) man page to reflect the new timer behavior.
  * Fix man page style issues in kqueue(2) diagnosed by igor.
  * Update the timer libkqueue system test to test for the updated
    timer behavior.
  * Fix the (test) libkqueue common.h file so that it includes
    config.h which defines various HAVE_* feature defines, before the
    #if tests for such variables in common.h. This enables the use of
    the actual err(3) family of functions.
  * Fix the usages of the err(3) functions in the tests for incorrect
    type of variables. Those were formerly undiagnosed due to the
    disablement of the err(3) functions (see previous bullet point).

PR:		214987
Reported by:	Brian Wellington <bwelling@xbill.org>
Reviewed by:	kib
MFC after:	1 week
Relnotes:	yes
Sponsored by:	Dell EMC
Differential Revision:	https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
* Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org>
* Copyright (c) 2009 Apple, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ktrace.h"
#include "opt_kqueue.h"
#ifdef COMPAT_FREEBSD11
#define _WANT_FREEBSD11_KEVENT
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/capsicum.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/rwlock.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/unistd.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/filio.h>
#include <sys/fcntl.h>
#include <sys/kthread.h>
#include <sys/selinfo.h>
#include <sys/queue.h>
#include <sys/event.h>
#include <sys/eventvar.h>
#include <sys/poll.h>
#include <sys/protosw.h>
#include <sys/resourcevar.h>
#include <sys/sigio.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/syscallsubr.h>
#include <sys/taskqueue.h>
#include <sys/uio.h>
#include <sys/user.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <machine/atomic.h>
#include <vm/uma.h>
static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
/*
* This lock is used if multiple kq locks are required. This possibly
* should be made into a per proc lock.
*/
static struct mtx kq_global;
MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
#define KQ_GLOBAL_LOCK(lck, haslck) do { \
if (!haslck) \
mtx_lock(lck); \
haslck = 1; \
} while (0)
#define KQ_GLOBAL_UNLOCK(lck, haslck) do { \
if (haslck) \
mtx_unlock(lck); \
haslck = 0; \
} while (0)
TASKQUEUE_DEFINE_THREAD(kqueue_ctx);
static int kevent_copyout(void *arg, struct kevent *kevp, int count);
static int kevent_copyin(void *arg, struct kevent *kevp, int count);
static int kqueue_register(struct kqueue *kq, struct kevent *kev,
struct thread *td, int waitok);
static int kqueue_acquire(struct file *fp, struct kqueue **kqp);
static void kqueue_release(struct kqueue *kq, int locked);
static void kqueue_destroy(struct kqueue *kq);
static void kqueue_drain(struct kqueue *kq, struct thread *td);
static int kqueue_expand(struct kqueue *kq, struct filterops *fops,
uintptr_t ident, int waitok);
static void kqueue_task(void *arg, int pending);
static int kqueue_scan(struct kqueue *kq, int maxevents,
struct kevent_copyops *k_ops,
const struct timespec *timeout,
struct kevent *keva, struct thread *td);
static void kqueue_wakeup(struct kqueue *kq);
static struct filterops *kqueue_fo_find(int filt);
static void kqueue_fo_release(int filt);
struct g_kevent_args;
static int kern_kevent_generic(struct thread *td,
struct g_kevent_args *uap,
struct kevent_copyops *k_ops, const char *struct_name);
static fo_ioctl_t kqueue_ioctl;
static fo_poll_t kqueue_poll;
static fo_kqfilter_t kqueue_kqfilter;
static fo_stat_t kqueue_stat;
static fo_close_t kqueue_close;
static fo_fill_kinfo_t kqueue_fill_kinfo;
static struct fileops kqueueops = {
.fo_read = invfo_rdwr,
.fo_write = invfo_rdwr,
.fo_truncate = invfo_truncate,
.fo_ioctl = kqueue_ioctl,
.fo_poll = kqueue_poll,
.fo_kqfilter = kqueue_kqfilter,
.fo_stat = kqueue_stat,
.fo_close = kqueue_close,
.fo_chmod = invfo_chmod,
.fo_chown = invfo_chown,
.fo_sendfile = invfo_sendfile,
.fo_fill_kinfo = kqueue_fill_kinfo,
};
static int knote_attach(struct knote *kn, struct kqueue *kq);
static void knote_drop(struct knote *kn, struct thread *td);
static void knote_drop_detached(struct knote *kn, struct thread *td);
static void knote_enqueue(struct knote *kn);
static void knote_dequeue(struct knote *kn);
static void knote_init(void);
static struct knote *knote_alloc(int waitok);
static void knote_free(struct knote *kn);
static void filt_kqdetach(struct knote *kn);
static int filt_kqueue(struct knote *kn, long hint);
static int filt_procattach(struct knote *kn);
static void filt_procdetach(struct knote *kn);
static int filt_proc(struct knote *kn, long hint);
static int filt_fileattach(struct knote *kn);
static void filt_timerexpire(void *knx);
static int filt_timerattach(struct knote *kn);
static void filt_timerdetach(struct knote *kn);
static void filt_timerstart(struct knote *kn, sbintime_t to);
static void filt_timertouch(struct knote *kn, struct kevent *kev,
u_long type);
static int filt_timervalidate(struct knote *kn, sbintime_t *to);
static int filt_timer(struct knote *kn, long hint);
static int filt_userattach(struct knote *kn);
static void filt_userdetach(struct knote *kn);
static int filt_user(struct knote *kn, long hint);
static void filt_usertouch(struct knote *kn, struct kevent *kev,
u_long type);
static struct filterops file_filtops = {
.f_isfd = 1,
.f_attach = filt_fileattach,
};
static struct filterops kqread_filtops = {
.f_isfd = 1,
.f_detach = filt_kqdetach,
.f_event = filt_kqueue,
};
/* XXX - move to kern_proc.c? */
static struct filterops proc_filtops = {
.f_isfd = 0,
.f_attach = filt_procattach,
.f_detach = filt_procdetach,
.f_event = filt_proc,
};
static struct filterops timer_filtops = {
.f_isfd = 0,
.f_attach = filt_timerattach,
.f_detach = filt_timerdetach,
.f_event = filt_timer,
.f_touch = filt_timertouch,
};
static struct filterops user_filtops = {
.f_attach = filt_userattach,
.f_detach = filt_userdetach,
.f_event = filt_user,
.f_touch = filt_usertouch,
};
static uma_zone_t knote_zone;
static unsigned int kq_ncallouts = 0;
static unsigned int kq_calloutmax = 4 * 1024;
SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
&kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
/* XXX - ensure not influx ? */
#define KNOTE_ACTIVATE(kn, islock) do { \
if ((islock)) \
mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
else \
KQ_LOCK((kn)->kn_kq); \
(kn)->kn_status |= KN_ACTIVE; \
if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
knote_enqueue((kn)); \
if (!(islock)) \
KQ_UNLOCK((kn)->kn_kq); \
} while(0)
#define KQ_LOCK(kq) do { \
mtx_lock(&(kq)->kq_lock); \
} while (0)
#define KQ_FLUX_WAKEUP(kq) do { \
if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
(kq)->kq_state &= ~KQ_FLUXWAIT; \
wakeup((kq)); \
} \
} while (0)
#define KQ_UNLOCK_FLUX(kq) do { \
KQ_FLUX_WAKEUP(kq); \
mtx_unlock(&(kq)->kq_lock); \
} while (0)
#define KQ_UNLOCK(kq) do { \
mtx_unlock(&(kq)->kq_lock); \
} while (0)
#define KQ_OWNED(kq) do { \
mtx_assert(&(kq)->kq_lock, MA_OWNED); \
} while (0)
#define KQ_NOTOWNED(kq) do { \
mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
} while (0)
static struct knlist *
kn_list_lock(struct knote *kn)
{
struct knlist *knl;
knl = kn->kn_knlist;
if (knl != NULL)
knl->kl_lock(knl->kl_lockarg);
return (knl);
}
static void
kn_list_unlock(struct knlist *knl)
{
bool do_free;
if (knl == NULL)
return;
do_free = knl->kl_autodestroy && knlist_empty(knl);
knl->kl_unlock(knl->kl_lockarg);
if (do_free) {
knlist_destroy(knl);
free(knl, M_KQUEUE);
}
}
static bool
kn_in_flux(struct knote *kn)
{
return (kn->kn_influx > 0);
}
static void
kn_enter_flux(struct knote *kn)
{
KQ_OWNED(kn->kn_kq);
MPASS(kn->kn_influx < INT_MAX);
kn->kn_influx++;
}
static bool
kn_leave_flux(struct knote *kn)
{
KQ_OWNED(kn->kn_kq);
MPASS(kn->kn_influx > 0);
kn->kn_influx--;
return (kn->kn_influx == 0);
}
#define KNL_ASSERT_LOCK(knl, islocked) do { \
if (islocked) \
KNL_ASSERT_LOCKED(knl); \
else \
KNL_ASSERT_UNLOCKED(knl); \
} while (0)
#ifdef INVARIANTS
#define KNL_ASSERT_LOCKED(knl) do { \
knl->kl_assert_locked((knl)->kl_lockarg); \
} while (0)
#define KNL_ASSERT_UNLOCKED(knl) do { \
knl->kl_assert_unlocked((knl)->kl_lockarg); \
} while (0)
#else /* !INVARIANTS */
#define KNL_ASSERT_LOCKED(knl) do {} while(0)
#define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
#endif /* INVARIANTS */
#ifndef KN_HASHSIZE
#define KN_HASHSIZE 64 /* XXX should be tunable */
#endif
#define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
static int
filt_nullattach(struct knote *kn)
{
return (ENXIO);
};
struct filterops null_filtops = {
.f_isfd = 0,
.f_attach = filt_nullattach,
};
/* XXX - make SYSINIT to add these, and move into respective modules. */
extern struct filterops sig_filtops;
extern struct filterops fs_filtops;
/*
* Table for for all system-defined filters.
*/
static struct mtx filterops_lock;
MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops",
MTX_DEF);
static struct {
struct filterops *for_fop;
int for_nolock;
int for_refcnt;
} sysfilt_ops[EVFILT_SYSCOUNT] = {
{ &file_filtops, 1 }, /* EVFILT_READ */
{ &file_filtops, 1 }, /* EVFILT_WRITE */
{ &null_filtops }, /* EVFILT_AIO */
{ &file_filtops, 1 }, /* EVFILT_VNODE */
{ &proc_filtops, 1 }, /* EVFILT_PROC */
{ &sig_filtops, 1 }, /* EVFILT_SIGNAL */
{ &timer_filtops, 1 }, /* EVFILT_TIMER */
{ &file_filtops, 1 }, /* EVFILT_PROCDESC */
{ &fs_filtops, 1 }, /* EVFILT_FS */
{ &null_filtops }, /* EVFILT_LIO */
{ &user_filtops, 1 }, /* EVFILT_USER */
{ &null_filtops }, /* EVFILT_SENDFILE */
{ &file_filtops, 1 }, /* EVFILT_EMPTY */
};
/*
* Simple redirection for all cdevsw style objects to call their fo_kqfilter
* method.
*/
static int
filt_fileattach(struct knote *kn)
{
return (fo_kqfilter(kn->kn_fp, kn));
}
/*ARGSUSED*/
static int
kqueue_kqfilter(struct file *fp, struct knote *kn)
{
struct kqueue *kq = kn->kn_fp->f_data;
if (kn->kn_filter != EVFILT_READ)
return (EINVAL);
kn->kn_status |= KN_KQUEUE;
kn->kn_fop = &kqread_filtops;
knlist_add(&kq->kq_sel.si_note, kn, 0);
return (0);
}
static void
filt_kqdetach(struct knote *kn)
{
struct kqueue *kq = kn->kn_fp->f_data;
knlist_remove(&kq->kq_sel.si_note, kn, 0);
}
/*ARGSUSED*/
static int
filt_kqueue(struct knote *kn, long hint)
{
struct kqueue *kq = kn->kn_fp->f_data;
kn->kn_data = kq->kq_count;
return (kn->kn_data > 0);
}
/* XXX - move to kern_proc.c? */
static int
filt_procattach(struct knote *kn)
{
struct proc *p;
int error;
bool exiting, immediate;
exiting = immediate = false;
if (kn->kn_sfflags & NOTE_EXIT)
p = pfind_any(kn->kn_id);
else
p = pfind(kn->kn_id);
if (p == NULL)
return (ESRCH);
if (p->p_flag & P_WEXIT)
exiting = true;
if ((error = p_cansee(curthread, p))) {
PROC_UNLOCK(p);
return (error);
}
kn->kn_ptr.p_proc = p;
kn->kn_flags |= EV_CLEAR; /* automatically set */
/*
* Internal flag indicating registration done by kernel for the
* purposes of getting a NOTE_CHILD notification.
*/
if (kn->kn_flags & EV_FLAG2) {
kn->kn_flags &= ~EV_FLAG2;
kn->kn_data = kn->kn_sdata; /* ppid */
kn->kn_fflags = NOTE_CHILD;
kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK);
immediate = true; /* Force immediate activation of child note. */
}
/*
* Internal flag indicating registration done by kernel (for other than
* NOTE_CHILD).
*/
if (kn->kn_flags & EV_FLAG1) {
kn->kn_flags &= ~EV_FLAG1;
}
knlist_add(p->p_klist, kn, 1);
/*
* Immediately activate any child notes or, in the case of a zombie
* target process, exit notes. The latter is necessary to handle the
* case where the target process, e.g. a child, dies before the kevent
* is registered.
*/
if (immediate || (exiting && filt_proc(kn, NOTE_EXIT)))
KNOTE_ACTIVATE(kn, 0);
PROC_UNLOCK(p);
return (0);
}
/*
* The knote may be attached to a different process, which may exit,
* leaving nothing for the knote to be attached to. So when the process
* exits, the knote is marked as DETACHED and also flagged as ONESHOT so
* it will be deleted when read out. However, as part of the knote deletion,
* this routine is called, so a check is needed to avoid actually performing
* a detach, because the original process does not exist any more.
*/
/* XXX - move to kern_proc.c? */
static void
filt_procdetach(struct knote *kn)
{
knlist_remove(kn->kn_knlist, kn, 0);
kn->kn_ptr.p_proc = NULL;
}
/* XXX - move to kern_proc.c? */
static int
filt_proc(struct knote *kn, long hint)
{
struct proc *p;
u_int event;
p = kn->kn_ptr.p_proc;
if (p == NULL) /* already activated, from attach filter */
return (0);
/* Mask off extra data. */
event = (u_int)hint & NOTE_PCTRLMASK;
/* If the user is interested in this event, record it. */
if (kn->kn_sfflags & event)
kn->kn_fflags |= event;
/* Process is gone, so flag the event as finished. */
if (event == NOTE_EXIT) {
kn->kn_flags |= EV_EOF | EV_ONESHOT;
kn->kn_ptr.p_proc = NULL;
if (kn->kn_fflags & NOTE_EXIT)
kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig);
if (kn->kn_fflags == 0)
kn->kn_flags |= EV_DROP;
return (1);
}
return (kn->kn_fflags != 0);
}
/*
* Called when the process forked. It mostly does the same as the
* knote(), activating all knotes registered to be activated when the
* process forked. Additionally, for each knote attached to the
* parent, check whether user wants to track the new process. If so
* attach a new knote to it, and immediately report an event with the
* child's pid.
*/
void
knote_fork(struct knlist *list, int pid)
{
struct kqueue *kq;
struct knote *kn;
struct kevent kev;
int error;
if (list == NULL)
return;
list->kl_lock(list->kl_lockarg);
SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
kq = kn->kn_kq;
KQ_LOCK(kq);
if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) {
KQ_UNLOCK(kq);
continue;
}
/*
* The same as knote(), activate the event.
*/
if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
kn->kn_status |= KN_HASKQLOCK;
if (kn->kn_fop->f_event(kn, NOTE_FORK))
KNOTE_ACTIVATE(kn, 1);
kn->kn_status &= ~KN_HASKQLOCK;
KQ_UNLOCK(kq);
continue;
}
/*
* The NOTE_TRACK case. In addition to the activation
* of the event, we need to register new events to
* track the child. Drop the locks in preparation for
* the call to kqueue_register().
*/
kn_enter_flux(kn);
KQ_UNLOCK(kq);
list->kl_unlock(list->kl_lockarg);
/*
* Activate existing knote and register tracking knotes with
* new process.
*
* First register a knote to get just the child notice. This
* must be a separate note from a potential NOTE_EXIT
* notification since both NOTE_CHILD and NOTE_EXIT are defined
* to use the data field (in conflicting ways).
*/
kev.ident = pid;
kev.filter = kn->kn_filter;
kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT |
EV_FLAG2;
kev.fflags = kn->kn_sfflags;
kev.data = kn->kn_id; /* parent */
kev.udata = kn->kn_kevent.udata;/* preserve udata */
error = kqueue_register(kq, &kev, NULL, 0);
if (error)
kn->kn_fflags |= NOTE_TRACKERR;
/*
* Then register another knote to track other potential events
* from the new process.
*/
kev.ident = pid;
kev.filter = kn->kn_filter;
kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
kev.fflags = kn->kn_sfflags;
kev.data = kn->kn_id; /* parent */
kev.udata = kn->kn_kevent.udata;/* preserve udata */
error = kqueue_register(kq, &kev, NULL, 0);
if (error)
kn->kn_fflags |= NOTE_TRACKERR;
if (kn->kn_fop->f_event(kn, NOTE_FORK))
KNOTE_ACTIVATE(kn, 0);
KQ_LOCK(kq);
kn_leave_flux(kn);
KQ_UNLOCK_FLUX(kq);
list->kl_lock(list->kl_lockarg);
}
list->kl_unlock(list->kl_lockarg);
}
/*
* XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the
* interval timer support code.
*/
#define NOTE_TIMER_PRECMASK \
(NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS)
static sbintime_t
timer2sbintime(intptr_t data, int flags)
{
int64_t secs;
/*
* Macros for converting to the fractional second portion of an
* sbintime_t using 64bit multiplication to improve precision.
*/
#define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32)
#define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32)
#define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32)
switch (flags & NOTE_TIMER_PRECMASK) {
case NOTE_SECONDS:
#ifdef __LP64__
if (data > (SBT_MAX / SBT_1S))
return (SBT_MAX);
#endif
return ((sbintime_t)data << 32);
case NOTE_MSECONDS: /* FALLTHROUGH */
case 0:
if (data >= 1000) {
secs = data / 1000;
#ifdef __LP64__
if (secs > (SBT_MAX / SBT_1S))
return (SBT_MAX);
#endif
return (secs << 32 | MS_TO_SBT(data % 1000));
}
return (MS_TO_SBT(data));
case NOTE_USECONDS:
if (data >= 1000000) {
secs = data / 1000000;
#ifdef __LP64__
if (secs > (SBT_MAX / SBT_1S))
return (SBT_MAX);
#endif
return (secs << 32 | US_TO_SBT(data % 1000000));
}
return (US_TO_SBT(data));
case NOTE_NSECONDS:
if (data >= 1000000000) {
secs = data / 1000000000;
#ifdef __LP64__
if (secs > (SBT_MAX / SBT_1S))
return (SBT_MAX);
#endif
return (secs << 32 | US_TO_SBT(data % 1000000000));
}
return (NS_TO_SBT(data));
default:
break;
}
return (-1);
}
struct kq_timer_cb_data {
struct callout c;
sbintime_t next; /* next timer event fires at */
sbintime_t to; /* precalculated timer period, 0 for abs */
};
static void
filt_timerexpire(void *knx)
{
struct knote *kn;
struct kq_timer_cb_data *kc;
kn = knx;
kn->kn_data++;
KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
if ((kn->kn_flags & EV_ONESHOT) != 0)
return;
kc = kn->kn_ptr.p_v;
if (kc->to == 0)
return;
kc->next += kc->to;
callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn,
PCPU_GET(cpuid), C_ABSOLUTE);
}
/*
* data contains amount of time to sleep
*/
static int
filt_timervalidate(struct knote *kn, sbintime_t *to)
{
struct bintime bt;
sbintime_t sbt;
if (kn->kn_sdata < 0)
return (EINVAL);
if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0)
kn->kn_sdata = 1;
/*
* The only fflags values supported are the timer unit
* (precision) and the absolute time indicator.
*/
if ((kn->kn_sfflags & ~(NOTE_TIMER_PRECMASK | NOTE_ABSTIME)) != 0)
return (EINVAL);
*to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags);
if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) {
getboottimebin(&bt);
sbt = bttosbt(bt);
*to -= sbt;
}
if (*to < 0)
return (EINVAL);
return (0);
}
static int
filt_timerattach(struct knote *kn)
{
struct kq_timer_cb_data *kc;
sbintime_t to;
unsigned int ncallouts;
int error;
error = filt_timervalidate(kn, &to);
if (error != 0)
return (error);
do {
ncallouts = kq_ncallouts;
if (ncallouts >= kq_calloutmax)
return (ENOMEM);
} while (!atomic_cmpset_int(&kq_ncallouts, ncallouts, ncallouts + 1));
if ((kn->kn_sfflags & NOTE_ABSTIME) == 0)
kn->kn_flags |= EV_CLEAR; /* automatically set */
kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */
kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK);
callout_init(&kc->c, 1);
filt_timerstart(kn, to);
return (0);
}
static void
filt_timerstart(struct knote *kn, sbintime_t to)
{
struct kq_timer_cb_data *kc;
kc = kn->kn_ptr.p_v;
if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) {
kc->next = to;
kc->to = 0;
} else {
kc->next = to + sbinuptime();
kc->to = to;
}
callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn,
PCPU_GET(cpuid), C_ABSOLUTE);
}
static void
filt_timerdetach(struct knote *kn)
{
struct kq_timer_cb_data *kc;
unsigned int old __unused;
kc = kn->kn_ptr.p_v;
callout_drain(&kc->c);
free(kc, M_KQUEUE);
old = atomic_fetchadd_int(&kq_ncallouts, -1);
KASSERT(old > 0, ("Number of callouts cannot become negative"));
kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */
}
static void
filt_timertouch(struct knote *kn, struct kevent *kev, u_long type)
{
struct kq_timer_cb_data *kc;
struct kqueue *kq;
sbintime_t to;
int error;
switch (type) {
case EVENT_REGISTER:
/* Handle re-added timers that update data/fflags */
if (kev->flags & EV_ADD) {
kc = kn->kn_ptr.p_v;
/* Drain any existing callout. */
callout_drain(&kc->c);
/* Throw away any existing undelivered record
* of the timer expiration. This is done under
* the presumption that if a process is
* re-adding this timer with new parameters,
* it is no longer interested in what may have
* happened under the old parameters. If it is
* interested, it can wait for the expiration,
* delete the old timer definition, and then
* add the new one.
*
* This has to be done while the kq is locked:
* - if enqueued, dequeue
* - make it no longer active
* - clear the count of expiration events
*/
kq = kn->kn_kq;
KQ_LOCK(kq);
if (kn->kn_status & KN_QUEUED)
knote_dequeue(kn);
kn->kn_status &= ~KN_ACTIVE;
kn->kn_data = 0;
KQ_UNLOCK(kq);
/* Reschedule timer based on new data/fflags */
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
error = filt_timervalidate(kn, &to);
if (error != 0) {
kn->kn_flags |= EV_ERROR;
kn->kn_data = error;
} else
filt_timerstart(kn, to);
}
break;
case EVENT_PROCESS:
*kev = kn->kn_kevent;
if (kn->kn_flags & EV_CLEAR) {
kn->kn_data = 0;
kn->kn_fflags = 0;
}
break;
default:
panic("filt_timertouch() - invalid type (%ld)", type);
break;
}
}
static int
filt_timer(struct knote *kn, long hint)
{
return (kn->kn_data != 0);
}
static int
filt_userattach(struct knote *kn)
{
/*
* EVFILT_USER knotes are not attached to anything in the kernel.
*/
kn->kn_hook = NULL;
if (kn->kn_fflags & NOTE_TRIGGER)
kn->kn_hookid = 1;
else
kn->kn_hookid = 0;
return (0);
}
static void
filt_userdetach(__unused struct knote *kn)
{
/*
* EVFILT_USER knotes are not attached to anything in the kernel.
*/
}
static int
filt_user(struct knote *kn, __unused long hint)
{
return (kn->kn_hookid);
}
static void
filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
{
u_int ffctrl;
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;
}
}
int
sys_kqueue(struct thread *td, struct kqueue_args *uap)
{
return (kern_kqueue(td, 0, NULL));
}
static void
kqueue_init(struct kqueue *kq)
{
mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK);
TAILQ_INIT(&kq->kq_head);
knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
}
int
kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps)
{
struct filedesc *fdp;
struct kqueue *kq;
struct file *fp;
struct ucred *cred;
int fd, error;
fdp = td->td_proc->p_fd;
cred = td->td_ucred;
if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES)))
return (ENOMEM);
error = falloc_caps(td, &fp, &fd, flags, fcaps);
if (error != 0) {
chgkqcnt(cred->cr_ruidinfo, -1, 0);
return (error);
}
/* An extra reference on `fp' has been held for us by falloc(). */
kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
kqueue_init(kq);
kq->kq_fdp = fdp;
kq->kq_cred = crhold(cred);
FILEDESC_XLOCK(fdp);
TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
FILEDESC_XUNLOCK(fdp);
finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
fdrop(fp, td);
td->td_retval[0] = fd;
return (0);
}
struct g_kevent_args {
int fd;
void *changelist;
int nchanges;
void *eventlist;
int nevents;
const struct timespec *timeout;
};
int
sys_kevent(struct thread *td, struct kevent_args *uap)
{
struct kevent_copyops k_ops = {
.arg = uap,
.k_copyout = kevent_copyout,
.k_copyin = kevent_copyin,
.kevent_size = sizeof(struct kevent),
};
struct g_kevent_args gk_args = {
.fd = uap->fd,
.changelist = uap->changelist,
.nchanges = uap->nchanges,
.eventlist = uap->eventlist,
.nevents = uap->nevents,
.timeout = uap->timeout,
};
return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent"));
}
static int
kern_kevent_generic(struct thread *td, struct g_kevent_args *uap,
struct kevent_copyops *k_ops, const char *struct_name)
{
struct timespec ts, *tsp;
#ifdef KTRACE
struct kevent *eventlist = uap->eventlist;
#endif
int error;
if (uap->timeout != NULL) {
error = copyin(uap->timeout, &ts, sizeof(ts));
if (error)
return (error);
tsp = &ts;
} else
tsp = NULL;
#ifdef KTRACE
if (KTRPOINT(td, KTR_STRUCT_ARRAY))
ktrstructarray(struct_name, UIO_USERSPACE, uap->changelist,
uap->nchanges, k_ops->kevent_size);
#endif
error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
k_ops, tsp);
#ifdef KTRACE
if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY))
ktrstructarray(struct_name, UIO_USERSPACE, eventlist,
td->td_retval[0], k_ops->kevent_size);
#endif
return (error);
}
/*
* Copy 'count' items into the destination list pointed to by uap->eventlist.
*/
static int
kevent_copyout(void *arg, struct kevent *kevp, int count)
{
struct kevent_args *uap;
int error;
KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
uap = (struct kevent_args *)arg;
error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
if (error == 0)
uap->eventlist += count;
return (error);
}
/*
* Copy 'count' items from the list pointed to by uap->changelist.
*/
static int
kevent_copyin(void *arg, struct kevent *kevp, int count)
{
struct kevent_args *uap;
int error;
KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
uap = (struct kevent_args *)arg;
error = copyin(uap->changelist, kevp, count * sizeof *kevp);
if (error == 0)
uap->changelist += count;
return (error);
}
#ifdef COMPAT_FREEBSD11
static int
kevent11_copyout(void *arg, struct kevent *kevp, int count)
{
struct freebsd11_kevent_args *uap;
struct kevent_freebsd11 kev11;
int error, i;
KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
uap = (struct freebsd11_kevent_args *)arg;
for (i = 0; i < count; i++) {
kev11.ident = kevp->ident;
kev11.filter = kevp->filter;
kev11.flags = kevp->flags;
kev11.fflags = kevp->fflags;
kev11.data = kevp->data;
kev11.udata = kevp->udata;
error = copyout(&kev11, uap->eventlist, sizeof(kev11));
if (error != 0)
break;
uap->eventlist++;
kevp++;
}
return (error);
}
/*
* Copy 'count' items from the list pointed to by uap->changelist.
*/
static int
kevent11_copyin(void *arg, struct kevent *kevp, int count)
{
struct freebsd11_kevent_args *uap;
struct kevent_freebsd11 kev11;
int error, i;
KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
uap = (struct freebsd11_kevent_args *)arg;
for (i = 0; i < count; i++) {
error = copyin(uap->changelist, &kev11, sizeof(kev11));
if (error != 0)
break;
kevp->ident = kev11.ident;
kevp->filter = kev11.filter;
kevp->flags = kev11.flags;
kevp->fflags = kev11.fflags;
kevp->data = (uintptr_t)kev11.data;
kevp->udata = kev11.udata;
bzero(&kevp->ext, sizeof(kevp->ext));
uap->changelist++;
kevp++;
}
return (error);
}
int
freebsd11_kevent(struct thread *td, struct freebsd11_kevent_args *uap)
{
struct kevent_copyops k_ops = {
.arg = uap,
.k_copyout = kevent11_copyout,
.k_copyin = kevent11_copyin,
.kevent_size = sizeof(struct kevent_freebsd11),
};
struct g_kevent_args gk_args = {
.fd = uap->fd,
.changelist = uap->changelist,
.nchanges = uap->nchanges,
.eventlist = uap->eventlist,
.nevents = uap->nevents,
.timeout = uap->timeout,
};
return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent_freebsd11"));
}
#endif
int
kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
struct kevent_copyops *k_ops, const struct timespec *timeout)
{
cap_rights_t rights;
struct file *fp;
int error;
cap_rights_init(&rights);
if (nchanges > 0)
cap_rights_set(&rights, CAP_KQUEUE_CHANGE);
if (nevents > 0)
cap_rights_set(&rights, CAP_KQUEUE_EVENT);
error = fget(td, fd, &rights, &fp);
if (error != 0)
return (error);
error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout);
fdrop(fp, td);
return (error);
}
static int
kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents,
struct kevent_copyops *k_ops, const struct timespec *timeout)
{
struct kevent keva[KQ_NEVENTS];
struct kevent *kevp, *changes;
int i, n, nerrors, error;
nerrors = 0;
while (nchanges > 0) {
n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
error = k_ops->k_copyin(k_ops->arg, keva, n);
if (error)
return (error);
changes = keva;
for (i = 0; i < n; i++) {
kevp = &changes[i];
if (!kevp->filter)
continue;
kevp->flags &= ~EV_SYSFLAGS;
error = kqueue_register(kq, kevp, td, 1);
if (error || (kevp->flags & EV_RECEIPT)) {
if (nevents == 0)
return (error);
kevp->flags = EV_ERROR;
kevp->data = error;
(void)k_ops->k_copyout(k_ops->arg, kevp, 1);
nevents--;
nerrors++;
}
}
nchanges -= n;
}
if (nerrors) {
td->td_retval[0] = nerrors;
return (0);
}
return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td));
}
int
kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
struct kevent_copyops *k_ops, const struct timespec *timeout)
{
struct kqueue *kq;
int error;
error = kqueue_acquire(fp, &kq);
if (error != 0)
return (error);
error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout);
kqueue_release(kq, 0);
return (error);
}
/*
* Performs a kevent() call on a temporarily created kqueue. This can be
* used to perform one-shot polling, similar to poll() and select().
*/
int
kern_kevent_anonymous(struct thread *td, int nevents,
struct kevent_copyops *k_ops)
{
struct kqueue kq = {};
int error;
kqueue_init(&kq);
kq.kq_refcnt = 1;
error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL);
kqueue_drain(&kq, td);
kqueue_destroy(&kq);
return (error);
}
int
kqueue_add_filteropts(int filt, struct filterops *filtops)
{
int error;
error = 0;
if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
printf(
"trying to add a filterop that is out of range: %d is beyond %d\n",
~filt, EVFILT_SYSCOUNT);
return EINVAL;
}
mtx_lock(&filterops_lock);
if (sysfilt_ops[~filt].for_fop != &null_filtops &&
sysfilt_ops[~filt].for_fop != NULL)
error = EEXIST;
else {
sysfilt_ops[~filt].for_fop = filtops;
sysfilt_ops[~filt].for_refcnt = 0;
}
mtx_unlock(&filterops_lock);
return (error);
}
int
kqueue_del_filteropts(int filt)
{
int error;
error = 0;
if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
return EINVAL;
mtx_lock(&filterops_lock);
if (sysfilt_ops[~filt].for_fop == &null_filtops ||
sysfilt_ops[~filt].for_fop == NULL)
error = EINVAL;
else if (sysfilt_ops[~filt].for_refcnt != 0)
error = EBUSY;
else {
sysfilt_ops[~filt].for_fop = &null_filtops;
sysfilt_ops[~filt].for_refcnt = 0;
}
mtx_unlock(&filterops_lock);
return error;
}
static struct filterops *
kqueue_fo_find(int filt)
{
if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
return NULL;
if (sysfilt_ops[~filt].for_nolock)
return sysfilt_ops[~filt].for_fop;
mtx_lock(&filterops_lock);
sysfilt_ops[~filt].for_refcnt++;
if (sysfilt_ops[~filt].for_fop == NULL)
sysfilt_ops[~filt].for_fop = &null_filtops;
mtx_unlock(&filterops_lock);
return sysfilt_ops[~filt].for_fop;
}
static void
kqueue_fo_release(int filt)
{
if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
return;
if (sysfilt_ops[~filt].for_nolock)
return;
mtx_lock(&filterops_lock);
KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
("filter object refcount not valid on release"));
sysfilt_ops[~filt].for_refcnt--;
mtx_unlock(&filterops_lock);
}
/*
* A ref to kq (obtained via kqueue_acquire) must be held. waitok will
* influence if memory allocation should wait. Make sure it is 0 if you
* hold any mutexes.
*/
static int
kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok)
{
struct filterops *fops;
struct file *fp;
struct knote *kn, *tkn;
struct knlist *knl;
int error, filt, event;
int haskqglobal, filedesc_unlock;
if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE))
return (EINVAL);
fp = NULL;
kn = NULL;
knl = NULL;
error = 0;
haskqglobal = 0;
filedesc_unlock = 0;
filt = kev->filter;
fops = kqueue_fo_find(filt);
if (fops == NULL)
return EINVAL;
if (kev->flags & EV_ADD) {
/*
* Prevent waiting with locks. Non-sleepable
* allocation failures are handled in the loop, only
* if the spare knote appears to be actually required.
*/
tkn = knote_alloc(waitok);
} else {
tkn = NULL;
}
findkn:
if (fops->f_isfd) {
KASSERT(td != NULL, ("td is NULL"));
if (kev->ident > INT_MAX)
error = EBADF;
else
error = fget(td, kev->ident, &cap_event_rights, &fp);
if (error)
goto done;
if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
kev->ident, 0) != 0) {
/* try again */
fdrop(fp, td);
fp = NULL;
error = kqueue_expand(kq, fops, kev->ident, waitok);
if (error)
goto done;
goto findkn;
}
if (fp->f_type == DTYPE_KQUEUE) {
/*
* If we add some intelligence about what we are doing,
* we should be able to support events on ourselves.
* We need to know when we are doing this to prevent
* getting both the knlist lock and the kq lock since
* they are the same thing.
*/
if (fp->f_data == kq) {
error = EINVAL;
goto done;
}
/*
* Pre-lock the filedesc before the global
* lock mutex, see the comment in
* kqueue_close().
*/
FILEDESC_XLOCK(td->td_proc->p_fd);
filedesc_unlock = 1;
KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
}
KQ_LOCK(kq);
if (kev->ident < kq->kq_knlistsize) {
SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
if (kev->filter == kn->kn_filter)
break;
}
} else {
if ((kev->flags & EV_ADD) == EV_ADD)
kqueue_expand(kq, fops, kev->ident, waitok);
KQ_LOCK(kq);
/*
* If possible, find an existing knote to use for this kevent.
*/
if (kev->filter == EVFILT_PROC &&
(kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) {
/* This is an internal creation of a process tracking
* note. Don't attempt to coalesce this with an
* existing note.
*/
;
} else if (kq->kq_knhashmask != 0) {
struct klist *list;
list = &kq->kq_knhash[
KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
SLIST_FOREACH(kn, list, kn_link)
if (kev->ident == kn->kn_id &&
kev->filter == kn->kn_filter)
break;
}
}
/* knote is in the process of changing, wait for it to stabilize. */
if (kn != NULL && kn_in_flux(kn)) {
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
if (filedesc_unlock) {
FILEDESC_XUNLOCK(td->td_proc->p_fd);
filedesc_unlock = 0;
}
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
if (fp != NULL) {
fdrop(fp, td);
fp = NULL;
}
goto findkn;
}
/*
* kn now contains the matching knote, or NULL if no match
*/
if (kn == NULL) {
if (kev->flags & EV_ADD) {
kn = tkn;
tkn = NULL;
if (kn == NULL) {
KQ_UNLOCK(kq);
error = ENOMEM;
goto done;
}
kn->kn_fp = fp;
kn->kn_kq = kq;
kn->kn_fop = fops;
/*
* apply reference counts to knote structure, and
* do not release it at the end of this routine.
*/
fops = NULL;
fp = NULL;
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
kev->fflags = 0;
kev->data = 0;
kn->kn_kevent = *kev;
kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT);
kn->kn_status = KN_DETACHED;
kn_enter_flux(kn);
error = knote_attach(kn, kq);
KQ_UNLOCK(kq);
if (error != 0) {
tkn = kn;
goto done;
}
if ((error = kn->kn_fop->f_attach(kn)) != 0) {
knote_drop_detached(kn, td);
goto done;
}
knl = kn_list_lock(kn);
goto done_ev_add;
} else {
/* No matching knote and the EV_ADD flag is not set. */
KQ_UNLOCK(kq);
error = ENOENT;
goto done;
}
}
if (kev->flags & EV_DELETE) {
kn_enter_flux(kn);
KQ_UNLOCK(kq);
knote_drop(kn, td);
goto done;
}
if (kev->flags & EV_FORCEONESHOT) {
kn->kn_flags |= EV_ONESHOT;
KNOTE_ACTIVATE(kn, 1);
}
/*
* The user may change some filter values after the initial EV_ADD,
* but doing so will not reset any filter which has already been
* triggered.
*/
kn->kn_status |= KN_SCAN;
kn_enter_flux(kn);
KQ_UNLOCK(kq);
knl = kn_list_lock(kn);
kn->kn_kevent.udata = kev->udata;
if (!fops->f_isfd && fops->f_touch != NULL) {
fops->f_touch(kn, kev, EVENT_REGISTER);
} else {
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
}
/*
* We can get here with kn->kn_knlist == NULL. This can happen when
* the initial attach event decides that the event is "completed"
* already. i.e. filt_procattach is called on a zombie process. It
* will call filt_proc which will remove it from the list, and NULL
* kn_knlist.
*/
done_ev_add:
if ((kev->flags & EV_ENABLE) != 0)
kn->kn_status &= ~KN_DISABLED;
else if ((kev->flags & EV_DISABLE) != 0)
kn->kn_status |= KN_DISABLED;
if ((kn->kn_status & KN_DISABLED) == 0)
event = kn->kn_fop->f_event(kn, 0);
else
event = 0;
KQ_LOCK(kq);
if (event)
kn->kn_status |= KN_ACTIVE;
if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) ==
KN_ACTIVE)
knote_enqueue(kn);
kn->kn_status &= ~KN_SCAN;
kn_leave_flux(kn);
kn_list_unlock(knl);
KQ_UNLOCK_FLUX(kq);
done:
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
if (filedesc_unlock)
FILEDESC_XUNLOCK(td->td_proc->p_fd);
if (fp != NULL)
fdrop(fp, td);
knote_free(tkn);
if (fops != NULL)
kqueue_fo_release(filt);
return (error);
}
static int
kqueue_acquire(struct file *fp, struct kqueue **kqp)
{
int error;
struct kqueue *kq;
error = 0;
kq = fp->f_data;
if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
return (EBADF);
*kqp = kq;
KQ_LOCK(kq);
if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
KQ_UNLOCK(kq);
return (EBADF);
}
kq->kq_refcnt++;
KQ_UNLOCK(kq);
return error;
}
static void
kqueue_release(struct kqueue *kq, int locked)
{
if (locked)
KQ_OWNED(kq);
else
KQ_LOCK(kq);
kq->kq_refcnt--;
if (kq->kq_refcnt == 1)
wakeup(&kq->kq_refcnt);
if (!locked)
KQ_UNLOCK(kq);
}
static void
kqueue_schedtask(struct kqueue *kq)
{
KQ_OWNED(kq);
KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
("scheduling kqueue task while draining"));
if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task);
kq->kq_state |= KQ_TASKSCHED;
}
}
/*
* Expand the kq to make sure we have storage for fops/ident pair.
*
* Return 0 on success (or no work necessary), return errno on failure.
*
* Not calling hashinit w/ waitok (proper malloc flag) should be safe.
* If kqueue_register is called from a non-fd context, there usually/should
* be no locks held.
*/
static int
kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident,
int waitok)
{
struct klist *list, *tmp_knhash, *to_free;
u_long tmp_knhashmask;
int size;
int fd;
int mflag = waitok ? M_WAITOK : M_NOWAIT;
KQ_NOTOWNED(kq);
to_free = NULL;
if (fops->f_isfd) {
fd = ident;
if (kq->kq_knlistsize <= fd) {
size = kq->kq_knlistsize;
while (size <= fd)
size += KQEXTENT;
list = malloc(size * sizeof(*list), M_KQUEUE, mflag);
if (list == NULL)
return ENOMEM;
KQ_LOCK(kq);
if (kq->kq_knlistsize > fd) {
to_free = list;
list = NULL;
} else {
if (kq->kq_knlist != NULL) {
bcopy(kq->kq_knlist, list,
kq->kq_knlistsize * sizeof(*list));
to_free = kq->kq_knlist;
kq->kq_knlist = NULL;
}
bzero((caddr_t)list +
kq->kq_knlistsize * sizeof(*list),
(size - kq->kq_knlistsize) * sizeof(*list));
kq->kq_knlistsize = size;
kq->kq_knlist = list;
}
KQ_UNLOCK(kq);
}
} else {
if (kq->kq_knhashmask == 0) {
tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
&tmp_knhashmask);
if (tmp_knhash == NULL)
return ENOMEM;
KQ_LOCK(kq);
if (kq->kq_knhashmask == 0) {
kq->kq_knhash = tmp_knhash;
kq->kq_knhashmask = tmp_knhashmask;
} else {
to_free = tmp_knhash;
}
KQ_UNLOCK(kq);
}
}
free(to_free, M_KQUEUE);
KQ_NOTOWNED(kq);
return 0;
}
static void
kqueue_task(void *arg, int pending)
{
struct kqueue *kq;
int haskqglobal;
haskqglobal = 0;
kq = arg;
KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
KQ_LOCK(kq);
KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
kq->kq_state &= ~KQ_TASKSCHED;
if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
wakeup(&kq->kq_state);
}
KQ_UNLOCK(kq);
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
}
/*
* Scan, update kn_data (if not ONESHOT), and copyout triggered events.
* We treat KN_MARKER knotes as if they are in flux.
*/
static int
kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
const struct timespec *tsp, struct kevent *keva, struct thread *td)
{
struct kevent *kevp;
struct knote *kn, *marker;
struct knlist *knl;
sbintime_t asbt, rsbt;
int count, error, haskqglobal, influx, nkev, touch;
count = maxevents;
nkev = 0;
error = 0;
haskqglobal = 0;
if (maxevents == 0)
goto done_nl;
rsbt = 0;
if (tsp != NULL) {
if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 ||
tsp->tv_nsec >= 1000000000) {
error = EINVAL;
goto done_nl;
}
if (timespecisset(tsp)) {
if (tsp->tv_sec <= INT32_MAX) {
rsbt = tstosbt(*tsp);
if (TIMESEL(&asbt, rsbt))
asbt += tc_tick_sbt;
if (asbt <= SBT_MAX - rsbt)
asbt += rsbt;
else
asbt = 0;
rsbt >>= tc_precexp;
} else
asbt = 0;
} else
asbt = -1;
} else
asbt = 0;
marker = knote_alloc(1);
marker->kn_status = KN_MARKER;
KQ_LOCK(kq);
retry:
kevp = keva;
if (kq->kq_count == 0) {
if (asbt == -1) {
error = EWOULDBLOCK;
} else {
kq->kq_state |= KQ_SLEEP;
error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH,
"kqread", asbt, rsbt, C_ABSOLUTE);
}
if (error == 0)
goto retry;
/* don't restart after signals... */
if (error == ERESTART)
error = EINTR;
else if (error == EWOULDBLOCK)
error = 0;
goto done;
}
TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
influx = 0;
while (count) {
KQ_OWNED(kq);
kn = TAILQ_FIRST(&kq->kq_head);
if ((kn->kn_status == KN_MARKER && kn != marker) ||
kn_in_flux(kn)) {
if (influx) {
influx = 0;
KQ_FLUX_WAKEUP(kq);
}
kq->kq_state |= KQ_FLUXWAIT;
error = msleep(kq, &kq->kq_lock, PSOCK,
"kqflxwt", 0);
continue;
}
TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
kn->kn_status &= ~KN_QUEUED;
kq->kq_count--;
continue;
}
if (kn == marker) {
KQ_FLUX_WAKEUP(kq);
if (count == maxevents)
goto retry;
goto done;
}
KASSERT(!kn_in_flux(kn),
("knote %p is unexpectedly in flux", kn));
if ((kn->kn_flags & EV_DROP) == EV_DROP) {
kn->kn_status &= ~KN_QUEUED;
kn_enter_flux(kn);
kq->kq_count--;
KQ_UNLOCK(kq);
/*
* We don't need to lock the list since we've
* marked it as in flux.
*/
knote_drop(kn, td);
KQ_LOCK(kq);
continue;
} else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
kn->kn_status &= ~KN_QUEUED;
kn_enter_flux(kn);
kq->kq_count--;
KQ_UNLOCK(kq);
/*
* We don't need to lock the list since we've
* marked the knote as being in flux.
*/
*kevp = kn->kn_kevent;
knote_drop(kn, td);
KQ_LOCK(kq);
kn = NULL;
} else {
kn->kn_status |= KN_SCAN;
kn_enter_flux(kn);
KQ_UNLOCK(kq);
if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
knl = kn_list_lock(kn);
if (kn->kn_fop->f_event(kn, 0) == 0) {
KQ_LOCK(kq);
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE |
KN_SCAN);
kn_leave_flux(kn);
kq->kq_count--;
kn_list_unlock(knl);
influx = 1;
continue;
}
touch = (!kn->kn_fop->f_isfd &&
kn->kn_fop->f_touch != NULL);
if (touch)
kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
else
*kevp = kn->kn_kevent;
KQ_LOCK(kq);
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
/*
* Manually clear knotes who weren't
* 'touch'ed.
*/
if (touch == 0 && kn->kn_flags & EV_CLEAR) {
kn->kn_data = 0;
kn->kn_fflags = 0;
}
if (kn->kn_flags & EV_DISPATCH)
kn->kn_status |= KN_DISABLED;
kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
kq->kq_count--;
} else
TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
kn->kn_status &= ~KN_SCAN;
kn_leave_flux(kn);
kn_list_unlock(knl);
influx = 1;
}
/* we are returning a copy to the user */
kevp++;
nkev++;
count--;
if (nkev == KQ_NEVENTS) {
influx = 0;
KQ_UNLOCK_FLUX(kq);
error = k_ops->k_copyout(k_ops->arg, keva, nkev);
nkev = 0;
kevp = keva;
KQ_LOCK(kq);
if (error)
break;
}
}
TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
done:
KQ_OWNED(kq);
KQ_UNLOCK_FLUX(kq);
knote_free(marker);
done_nl:
KQ_NOTOWNED(kq);
if (nkev != 0)
error = k_ops->k_copyout(k_ops->arg, keva, nkev);
td->td_retval[0] = maxevents - count;
return (error);
}
/*ARGSUSED*/
static int
kqueue_ioctl(struct file *fp, u_long cmd, void *data,
struct ucred *active_cred, struct thread *td)
{
/*
* Enabling sigio causes two major problems:
* 1) infinite recursion:
* Synopsys: kevent is being used to track signals and have FIOASYNC
* set. On receipt of a signal this will cause a kqueue to recurse
* into itself over and over. Sending the sigio causes the kqueue
* to become ready, which in turn posts sigio again, forever.
* Solution: this can be solved by setting a flag in the kqueue that
* we have a SIGIO in progress.
* 2) locking problems:
* Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
* us above the proc and pgrp locks.
* Solution: Post a signal using an async mechanism, being sure to
* record a generation count in the delivery so that we do not deliver
* a signal to the wrong process.
*
* Note, these two mechanisms are somewhat mutually exclusive!
*/
#if 0
struct kqueue *kq;
kq = fp->f_data;
switch (cmd) {
case FIOASYNC:
if (*(int *)data) {
kq->kq_state |= KQ_ASYNC;
} else {
kq->kq_state &= ~KQ_ASYNC;
}
return (0);
case FIOSETOWN:
return (fsetown(*(int *)data, &kq->kq_sigio));
case FIOGETOWN:
*(int *)data = fgetown(&kq->kq_sigio);
return (0);
}
#endif
return (ENOTTY);
}
/*ARGSUSED*/
static int
kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
struct thread *td)
{
struct kqueue *kq;
int revents = 0;
int error;
if ((error = kqueue_acquire(fp, &kq)))
return POLLERR;
KQ_LOCK(kq);
if (events & (POLLIN | POLLRDNORM)) {
if (kq->kq_count) {
revents |= events & (POLLIN | POLLRDNORM);
} else {
selrecord(td, &kq->kq_sel);
if (SEL_WAITING(&kq->kq_sel))
kq->kq_state |= KQ_SEL;
}
}
kqueue_release(kq, 1);
KQ_UNLOCK(kq);
return (revents);
}
/*ARGSUSED*/
static int
kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
struct thread *td)
{
bzero((void *)st, sizeof *st);
/*
* We no longer return kq_count because the unlocked value is useless.
* If you spent all this time getting the count, why not spend your
* syscall better by calling kevent?
*
* XXX - This is needed for libc_r.
*/
st->st_mode = S_IFIFO;
return (0);
}
static void
kqueue_drain(struct kqueue *kq, struct thread *td)
{
struct knote *kn;
int i;
KQ_LOCK(kq);
KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
("kqueue already closing"));
kq->kq_state |= KQ_CLOSING;
if (kq->kq_refcnt > 1)
msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
KASSERT(knlist_empty(&kq->kq_sel.si_note),
("kqueue's knlist not empty"));
for (i = 0; i < kq->kq_knlistsize; i++) {
while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
if (kn_in_flux(kn)) {
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
continue;
}
kn_enter_flux(kn);
KQ_UNLOCK(kq);
knote_drop(kn, td);
KQ_LOCK(kq);
}
}
if (kq->kq_knhashmask != 0) {
for (i = 0; i <= kq->kq_knhashmask; i++) {
while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
if (kn_in_flux(kn)) {
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK,
"kqclo2", 0);
continue;
}
kn_enter_flux(kn);
KQ_UNLOCK(kq);
knote_drop(kn, td);
KQ_LOCK(kq);
}
}
}
if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
kq->kq_state |= KQ_TASKDRAIN;
msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
}
if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
selwakeuppri(&kq->kq_sel, PSOCK);
if (!SEL_WAITING(&kq->kq_sel))
kq->kq_state &= ~KQ_SEL;
}
KQ_UNLOCK(kq);
}
static void
kqueue_destroy(struct kqueue *kq)
{
KASSERT(kq->kq_fdp == NULL,
("kqueue still attached to a file descriptor"));
seldrain(&kq->kq_sel);
knlist_destroy(&kq->kq_sel.si_note);
mtx_destroy(&kq->kq_lock);
if (kq->kq_knhash != NULL)
free(kq->kq_knhash, M_KQUEUE);
if (kq->kq_knlist != NULL)
free(kq->kq_knlist, M_KQUEUE);
funsetown(&kq->kq_sigio);
}
/*ARGSUSED*/
static int
kqueue_close(struct file *fp, struct thread *td)
{
struct kqueue *kq = fp->f_data;
struct filedesc *fdp;
int error;
int filedesc_unlock;
if ((error = kqueue_acquire(fp, &kq)))
return error;
kqueue_drain(kq, td);
/*
* We could be called due to the knote_drop() doing fdrop(),
* called from kqueue_register(). In this case the global
* lock is owned, and filedesc sx is locked before, to not
* take the sleepable lock after non-sleepable.
*/
fdp = kq->kq_fdp;
kq->kq_fdp = NULL;
if (!sx_xlocked(FILEDESC_LOCK(fdp))) {
FILEDESC_XLOCK(fdp);
filedesc_unlock = 1;
} else
filedesc_unlock = 0;
TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list);
if (filedesc_unlock)
FILEDESC_XUNLOCK(fdp);
kqueue_destroy(kq);
chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0);
crfree(kq->kq_cred);
free(kq, M_KQUEUE);
fp->f_data = NULL;
return (0);
}
static int
kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
{
kif->kf_type = KF_TYPE_KQUEUE;
return (0);
}
static void
kqueue_wakeup(struct kqueue *kq)
{
KQ_OWNED(kq);
if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
kq->kq_state &= ~KQ_SLEEP;
wakeup(kq);
}
if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
selwakeuppri(&kq->kq_sel, PSOCK);
if (!SEL_WAITING(&kq->kq_sel))
kq->kq_state &= ~KQ_SEL;
}
if (!knlist_empty(&kq->kq_sel.si_note))
kqueue_schedtask(kq);
if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
pgsigio(&kq->kq_sigio, SIGIO, 0);
}
}
/*
* Walk down a list of knotes, activating them if their event has triggered.
*
* There is a possibility to optimize in the case of one kq watching another.
* Instead of scheduling a task to wake it up, you could pass enough state
* down the chain to make up the parent kqueue. Make this code functional
* first.
*/
void
knote(struct knlist *list, long hint, int lockflags)
{
struct kqueue *kq;
struct knote *kn, *tkn;
int error;
if (list == NULL)
return;
KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
if ((lockflags & KNF_LISTLOCKED) == 0)
list->kl_lock(list->kl_lockarg);
/*
* If we unlock the list lock (and enter influx), we can
* eliminate the kqueue scheduling, but this will introduce
* four lock/unlock's for each knote to test. Also, marker
* would be needed to keep iteration position, since filters
* or other threads could remove events.
*/
SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) {
kq = kn->kn_kq;
KQ_LOCK(kq);
if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) {
/*
* Do not process the influx notes, except for
* the influx coming from the kq unlock in the
* kqueue_scan(). In the later case, we do
* not interfere with the scan, since the code
* fragment in kqueue_scan() locks the knlist,
* and cannot proceed until we finished.
*/
KQ_UNLOCK(kq);
} else if ((lockflags & KNF_NOKQLOCK) != 0) {
kn_enter_flux(kn);
KQ_UNLOCK(kq);
error = kn->kn_fop->f_event(kn, hint);
KQ_LOCK(kq);
kn_leave_flux(kn);
if (error)
KNOTE_ACTIVATE(kn, 1);
KQ_UNLOCK_FLUX(kq);
} else {
kn->kn_status |= KN_HASKQLOCK;
if (kn->kn_fop->f_event(kn, hint))
KNOTE_ACTIVATE(kn, 1);
kn->kn_status &= ~KN_HASKQLOCK;
KQ_UNLOCK(kq);
}
}
if ((lockflags & KNF_LISTLOCKED) == 0)
list->kl_unlock(list->kl_lockarg);
}
/*
* add a knote to a knlist
*/
void
knlist_add(struct knlist *knl, struct knote *kn, int islocked)
{
KNL_ASSERT_LOCK(knl, islocked);
KQ_NOTOWNED(kn->kn_kq);
KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn));
KASSERT((kn->kn_status & KN_DETACHED) != 0,
("knote %p was not detached", kn));
if (!islocked)
knl->kl_lock(knl->kl_lockarg);
SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
if (!islocked)
knl->kl_unlock(knl->kl_lockarg);
KQ_LOCK(kn->kn_kq);
kn->kn_knlist = knl;
kn->kn_status &= ~KN_DETACHED;
KQ_UNLOCK(kn->kn_kq);
}
static void
knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked,
int kqislocked)
{
KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked"));
KNL_ASSERT_LOCK(knl, knlislocked);
mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn));
KASSERT((kn->kn_status & KN_DETACHED) == 0,
("knote %p was already detached", kn));
if (!knlislocked)
knl->kl_lock(knl->kl_lockarg);
SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
kn->kn_knlist = NULL;
if (!knlislocked)
kn_list_unlock(knl);
if (!kqislocked)
KQ_LOCK(kn->kn_kq);
kn->kn_status |= KN_DETACHED;
if (!kqislocked)
KQ_UNLOCK(kn->kn_kq);
}
/*
* remove knote from the specified knlist
*/
void
knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
{
knlist_remove_kq(knl, kn, islocked, 0);
}
int
knlist_empty(struct knlist *knl)
{
KNL_ASSERT_LOCKED(knl);
return (SLIST_EMPTY(&knl->kl_list));
}
static struct mtx knlist_lock;
MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
MTX_DEF);
static void knlist_mtx_lock(void *arg);
static void knlist_mtx_unlock(void *arg);
static void
knlist_mtx_lock(void *arg)
{
mtx_lock((struct mtx *)arg);
}
static void
knlist_mtx_unlock(void *arg)
{
mtx_unlock((struct mtx *)arg);
}
static void
knlist_mtx_assert_locked(void *arg)
{
mtx_assert((struct mtx *)arg, MA_OWNED);
}
static void
knlist_mtx_assert_unlocked(void *arg)
{
mtx_assert((struct mtx *)arg, MA_NOTOWNED);
}
static void
knlist_rw_rlock(void *arg)
{
rw_rlock((struct rwlock *)arg);
}
static void
knlist_rw_runlock(void *arg)
{
rw_runlock((struct rwlock *)arg);
}
static void
knlist_rw_assert_locked(void *arg)
{
rw_assert((struct rwlock *)arg, RA_LOCKED);
}
static void
knlist_rw_assert_unlocked(void *arg)
{
rw_assert((struct rwlock *)arg, RA_UNLOCKED);
}
void
knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
void (*kl_unlock)(void *),
void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *))
{
if (lock == NULL)
knl->kl_lockarg = &knlist_lock;
else
knl->kl_lockarg = lock;
if (kl_lock == NULL)
knl->kl_lock = knlist_mtx_lock;
else
knl->kl_lock = kl_lock;
if (kl_unlock == NULL)
knl->kl_unlock = knlist_mtx_unlock;
else
knl->kl_unlock = kl_unlock;
if (kl_assert_locked == NULL)
knl->kl_assert_locked = knlist_mtx_assert_locked;
else
knl->kl_assert_locked = kl_assert_locked;
if (kl_assert_unlocked == NULL)
knl->kl_assert_unlocked = knlist_mtx_assert_unlocked;
else
knl->kl_assert_unlocked = kl_assert_unlocked;
knl->kl_autodestroy = 0;
SLIST_INIT(&knl->kl_list);
}
void
knlist_init_mtx(struct knlist *knl, struct mtx *lock)
{
knlist_init(knl, lock, NULL, NULL, NULL, NULL);
}
struct knlist *
knlist_alloc(struct mtx *lock)
{
struct knlist *knl;
knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK);
knlist_init_mtx(knl, lock);
return (knl);
}
void
knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock)
{
knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock,
knlist_rw_assert_locked, knlist_rw_assert_unlocked);
}
void
knlist_destroy(struct knlist *knl)
{
KASSERT(KNLIST_EMPTY(knl),
("destroying knlist %p with knotes on it", knl));
}
void
knlist_detach(struct knlist *knl)
{
KNL_ASSERT_LOCKED(knl);
knl->kl_autodestroy = 1;
if (knlist_empty(knl)) {
knlist_destroy(knl);
free(knl, M_KQUEUE);
}
}
/*
* Even if we are locked, we may need to drop the lock to allow any influx
* knotes time to "settle".
*/
void
knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
{
struct knote *kn, *kn2;
struct kqueue *kq;
KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl));
if (islocked)
KNL_ASSERT_LOCKED(knl);
else {
KNL_ASSERT_UNLOCKED(knl);
again: /* need to reacquire lock since we have dropped it */
knl->kl_lock(knl->kl_lockarg);
}
SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
kq = kn->kn_kq;
KQ_LOCK(kq);
if (kn_in_flux(kn)) {
KQ_UNLOCK(kq);
continue;
}
knlist_remove_kq(knl, kn, 1, 1);
if (killkn) {
kn_enter_flux(kn);
KQ_UNLOCK(kq);
knote_drop_detached(kn, td);
} else {
/* Make sure cleared knotes disappear soon */
kn->kn_flags |= EV_EOF | EV_ONESHOT;
KQ_UNLOCK(kq);
}
kq = NULL;
}
if (!SLIST_EMPTY(&knl->kl_list)) {
/* there are still in flux knotes remaining */
kn = SLIST_FIRST(&knl->kl_list);
kq = kn->kn_kq;
KQ_LOCK(kq);
KASSERT(kn_in_flux(kn), ("knote removed w/o list lock"));
knl->kl_unlock(knl->kl_lockarg);
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
kq = NULL;
goto again;
}
if (islocked)
KNL_ASSERT_LOCKED(knl);
else {
knl->kl_unlock(knl->kl_lockarg);
KNL_ASSERT_UNLOCKED(knl);
}
}
/*
* Remove all knotes referencing a specified fd must be called with FILEDESC
* lock. This prevents a race where a new fd comes along and occupies the
* entry and we attach a knote to the fd.
*/
void
knote_fdclose(struct thread *td, int fd)
{
struct filedesc *fdp = td->td_proc->p_fd;
struct kqueue *kq;
struct knote *kn;
int influx;
FILEDESC_XLOCK_ASSERT(fdp);
/*
* We shouldn't have to worry about new kevents appearing on fd
* since filedesc is locked.
*/
TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
KQ_LOCK(kq);
again:
influx = 0;
while (kq->kq_knlistsize > fd &&
(kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
if (kn_in_flux(kn)) {
/* someone else might be waiting on our knote */
if (influx)
wakeup(kq);
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
goto again;
}
kn_enter_flux(kn);
KQ_UNLOCK(kq);
influx = 1;
knote_drop(kn, td);
KQ_LOCK(kq);
}
KQ_UNLOCK_FLUX(kq);
}
}
static int
knote_attach(struct knote *kn, struct kqueue *kq)
{
struct klist *list;
KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn));
KQ_OWNED(kq);
if (kn->kn_fop->f_isfd) {
if (kn->kn_id >= kq->kq_knlistsize)
return (ENOMEM);
list = &kq->kq_knlist[kn->kn_id];
} else {
if (kq->kq_knhash == NULL)
return (ENOMEM);
list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
}
SLIST_INSERT_HEAD(list, kn, kn_link);
return (0);
}
static void
knote_drop(struct knote *kn, struct thread *td)
{
if ((kn->kn_status & KN_DETACHED) == 0)
kn->kn_fop->f_detach(kn);
knote_drop_detached(kn, td);
}
static void
knote_drop_detached(struct knote *kn, struct thread *td)
{
struct kqueue *kq;
struct klist *list;
kq = kn->kn_kq;
KASSERT((kn->kn_status & KN_DETACHED) != 0,
("knote %p still attached", kn));
KQ_NOTOWNED(kq);
KQ_LOCK(kq);
KASSERT(kn->kn_influx == 1,
("knote_drop called on %p with influx %d", kn, kn->kn_influx));
if (kn->kn_fop->f_isfd)
list = &kq->kq_knlist[kn->kn_id];
else
list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
if (!SLIST_EMPTY(list))
SLIST_REMOVE(list, kn, knote, kn_link);
if (kn->kn_status & KN_QUEUED)
knote_dequeue(kn);
KQ_UNLOCK_FLUX(kq);
if (kn->kn_fop->f_isfd) {
fdrop(kn->kn_fp, td);
kn->kn_fp = NULL;
}
kqueue_fo_release(kn->kn_kevent.filter);
kn->kn_fop = NULL;
knote_free(kn);
}
static void
knote_enqueue(struct knote *kn)
{
struct kqueue *kq = kn->kn_kq;
KQ_OWNED(kn->kn_kq);
KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
kn->kn_status |= KN_QUEUED;
kq->kq_count++;
kqueue_wakeup(kq);
}
static void
knote_dequeue(struct knote *kn)
{
struct kqueue *kq = kn->kn_kq;
KQ_OWNED(kn->kn_kq);
KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
kn->kn_status &= ~KN_QUEUED;
kq->kq_count--;
}
static void
knote_init(void)
{
knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, 0);
}
SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
static struct knote *
knote_alloc(int waitok)
{
return (uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT) |
M_ZERO));
}
static void
knote_free(struct knote *kn)
{
uma_zfree(knote_zone, kn);
}
/*
* Register the kev w/ the kq specified by fd.
*/
int
kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok)
{
struct kqueue *kq;
struct file *fp;
cap_rights_t rights;
int error;
error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp);
if (error != 0)
return (error);
if ((error = kqueue_acquire(fp, &kq)) != 0)
goto noacquire;
error = kqueue_register(kq, kev, td, waitok);
kqueue_release(kq, 0);
noacquire:
fdrop(fp, td);
return (error);
}
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