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freebsd/sys/kern/kern_event.c
John-Mark Gurney 33fabe46da remove unnecessary NULL check... 
Coverity ID:	1545
2006-09-25 01:29:48 +00:00

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/*-
* Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
* Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org>
* 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 <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.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/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>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#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);
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_aquire(struct file *fp, struct kqueue **kqp);
static void kqueue_release(struct kqueue *kq, int locked);
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);
static fo_rdwr_t kqueue_read;
static fo_rdwr_t kqueue_write;
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 struct fileops kqueueops = {
.fo_read = kqueue_read,
.fo_write = kqueue_write,
.fo_ioctl = kqueue_ioctl,
.fo_poll = kqueue_poll,
.fo_kqfilter = kqueue_kqfilter,
.fo_stat = kqueue_stat,
.fo_close = kqueue_close,
};
static int knote_attach(struct knote *kn, struct kqueue *kq);
static void knote_drop(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 int filt_timer(struct knote *kn, long hint);
static struct filterops file_filtops =
{ 1, filt_fileattach, NULL, NULL };
static struct filterops kqread_filtops =
{ 1, NULL, filt_kqdetach, filt_kqueue };
/* XXX - move to kern_proc.c? */
static struct filterops proc_filtops =
{ 0, filt_procattach, filt_procdetach, filt_proc };
static struct filterops timer_filtops =
{ 0, filt_timerattach, filt_timerdetach, filt_timer };
static uma_zone_t knote_zone;
static int kq_ncallouts = 0;
static int kq_calloutmax = (4 * 1024);
SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
&kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
/* XXX - ensure not KN_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)
#define KN_LIST_LOCK(kn) do { \
if (kn->kn_knlist != NULL) \
kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \
} while (0)
#define KN_LIST_UNLOCK(kn) do { \
if (kn->kn_knlist != NULL) \
kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \
} while (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 { \
if (!knl->kl_locked((knl)->kl_lockarg)) \
panic("knlist not locked, but should be"); \
} while (0)
#define KNL_ASSERT_UNLOCKED(knl) do { \
if (knl->kl_locked((knl)->kl_lockarg)) \
panic("knlist locked, but should not be"); \
} while (0)
#else /* !INVARIANTS */
#define KNL_ASSERT_LOCKED(knl) do {} while(0)
#define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
#endif /* INVARIANTS */
#define KN_HASHSIZE 64 /* XXX should be tunable */
#define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
static int
filt_nullattach(struct knote *kn)
{
return (ENXIO);
};
struct filterops null_filtops =
{ 0, filt_nullattach, NULL, NULL };
/* 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_refcnt;
} sysfilt_ops[EVFILT_SYSCOUNT] = {
{ &file_filtops }, /* EVFILT_READ */
{ &file_filtops }, /* EVFILT_WRITE */
{ &null_filtops }, /* EVFILT_AIO */
{ &file_filtops }, /* EVFILT_VNODE */
{ &proc_filtops }, /* EVFILT_PROC */
{ &sig_filtops }, /* EVFILT_SIGNAL */
{ &timer_filtops }, /* EVFILT_TIMER */
{ &file_filtops }, /* EVFILT_NETDEV */
{ &fs_filtops }, /* EVFILT_FS */
{ &null_filtops }, /* EVFILT_LIO */
};
/*
* 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 immediate;
int error;
immediate = 0;
p = pfind(kn->kn_id);
if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
p = zpfind(kn->kn_id);
immediate = 1;
} else if (p != NULL && (p->p_flag & P_WEXIT)) {
immediate = 1;
}
if (p == NULL)
return (ESRCH);
if ((error = p_cansee(curthread, p)))
return (error);
kn->kn_ptr.p_proc = p;
kn->kn_flags |= EV_CLEAR; /* automatically set */
/*
* internal flag indicating registration done by kernel
*/
if (kn->kn_flags & EV_FLAG1) {
kn->kn_data = kn->kn_sdata; /* ppid */
kn->kn_fflags = NOTE_CHILD;
kn->kn_flags &= ~EV_FLAG1;
}
if (immediate == 0)
knlist_add(&p->p_klist, kn, 1);
/*
* Immediately activate any exit notes if the target process is a
* zombie. This is necessary to handle the case where the target
* process, e.g. a child, dies before the kevent is registered.
*/
if (immediate && 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)
{
struct proc *p;
p = kn->kn_ptr.p_proc;
knlist_remove(&p->p_klist, 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 = kn->kn_ptr.p_proc;
u_int event;
/*
* 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) {
if (!(kn->kn_status & KN_DETACHED))
knlist_remove_inevent(&p->p_klist, kn);
kn->kn_flags |= (EV_EOF | EV_ONESHOT);
kn->kn_ptr.p_proc = NULL;
return (1);
}
/*
* process forked, and user wants to track the new process,
* so attach a new knote to it, and immediately report an
* event with the parent's pid.
*/
if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
struct kevent kev;
int error;
/*
* register knote with new process.
*/
kev.ident = hint & NOTE_PDATAMASK; /* 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(kn->kn_kq, &kev, NULL, 0);
if (error)
kn->kn_fflags |= NOTE_TRACKERR;
}
return (kn->kn_fflags != 0);
}
static int
timertoticks(intptr_t data)
{
struct timeval tv;
int tticks;
tv.tv_sec = data / 1000;
tv.tv_usec = (data % 1000) * 1000;
tticks = tvtohz(&tv);
return tticks;
}
/* XXX - move to kern_timeout.c? */
static void
filt_timerexpire(void *knx)
{
struct knote *kn = knx;
struct callout *calloutp;
kn->kn_data++;
KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) {
calloutp = (struct callout *)kn->kn_hook;
callout_reset(calloutp, timertoticks(kn->kn_sdata),
filt_timerexpire, kn);
}
}
/*
* data contains amount of time to sleep, in milliseconds
*/
/* XXX - move to kern_timeout.c? */
static int
filt_timerattach(struct knote *kn)
{
struct callout *calloutp;
atomic_add_int(&kq_ncallouts, 1);
if (kq_ncallouts >= kq_calloutmax) {
atomic_add_int(&kq_ncallouts, -1);
return (ENOMEM);
}
kn->kn_flags |= EV_CLEAR; /* automatically set */
kn->kn_status &= ~KN_DETACHED; /* knlist_add usually sets it */
MALLOC(calloutp, struct callout *, sizeof(*calloutp),
M_KQUEUE, M_WAITOK);
callout_init(calloutp, CALLOUT_MPSAFE);
kn->kn_hook = calloutp;
callout_reset(calloutp, timertoticks(kn->kn_sdata), filt_timerexpire,
kn);
return (0);
}
/* XXX - move to kern_timeout.c? */
static void
filt_timerdetach(struct knote *kn)
{
struct callout *calloutp;
calloutp = (struct callout *)kn->kn_hook;
callout_drain(calloutp);
FREE(calloutp, M_KQUEUE);
atomic_add_int(&kq_ncallouts, -1);
kn->kn_status |= KN_DETACHED; /* knlist_remove usually clears it */
}
/* XXX - move to kern_timeout.c? */
static int
filt_timer(struct knote *kn, long hint)
{
return (kn->kn_data != 0);
}
/*
* MPSAFE
*/
int
kqueue(struct thread *td, struct kqueue_args *uap)
{
struct filedesc *fdp;
struct kqueue *kq;
struct file *fp;
int fd, error;
fdp = td->td_proc->p_fd;
error = falloc(td, &fp, &fd);
if (error)
goto done2;
/* An extra reference on `nfp' has been held for us by falloc(). */
kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK);
TAILQ_INIT(&kq->kq_head);
kq->kq_fdp = fdp;
knlist_init(&kq->kq_sel.si_note, &kq->kq_lock, NULL, NULL, NULL);
TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
FILEDESC_LOCK_FAST(fdp);
SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
FILEDESC_UNLOCK_FAST(fdp);
FILE_LOCK(fp);
fp->f_flag = FREAD | FWRITE;
fp->f_type = DTYPE_KQUEUE;
fp->f_ops = &kqueueops;
fp->f_data = kq;
FILE_UNLOCK(fp);
fdrop(fp, td);
td->td_retval[0] = fd;
done2:
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct kevent_args {
int fd;
const struct kevent *changelist;
int nchanges;
struct kevent *eventlist;
int nevents;
const struct timespec *timeout;
};
#endif
/*
* MPSAFE
*/
int
kevent(struct thread *td, struct kevent_args *uap)
{
struct timespec ts, *tsp;
struct kevent_copyops k_ops = { uap,
kevent_copyout,
kevent_copyin};
int error;
#ifdef KTRACE
struct uio ktruio;
struct iovec ktriov;
struct uio *ktruioin = NULL;
struct uio *ktruioout = NULL;
#endif
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_GENIO)) {
ktriov.iov_base = uap->changelist;
ktriov.iov_len = uap->nchanges * sizeof(struct kevent);
ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1,
.uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ,
.uio_td = td };
ktruioin = cloneuio(&ktruio);
ktriov.iov_base = uap->eventlist;
ktriov.iov_len = uap->nevents * sizeof(struct kevent);
ktruioout = cloneuio(&ktruio);
}
#endif
error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
&k_ops, tsp);
#ifdef KTRACE
if (ktruioin != NULL) {
ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent);
ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0);
ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent);
ktrgenio(uap->fd, UIO_READ, ktruioout, error);
}
#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);
}
int
kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
struct kevent_copyops *k_ops, const struct timespec *timeout)
{
struct kevent keva[KQ_NEVENTS];
struct kevent *kevp, *changes;
struct kqueue *kq;
struct file *fp;
int i, n, nerrors, error;
if ((error = fget(td, fd, &fp)) != 0)
return (error);
if ((error = kqueue_aquire(fp, &kq)) != 0)
goto done_norel;
nerrors = 0;
while (nchanges > 0) {
n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
error = k_ops->k_copyin(k_ops->arg, keva, n);
if (error)
goto done;
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) {
if (nevents != 0) {
kevp->flags = EV_ERROR;
kevp->data = error;
(void) k_ops->k_copyout(k_ops->arg,
kevp, 1);
nevents--;
nerrors++;
} else {
goto done;
}
}
}
nchanges -= n;
}
if (nerrors) {
td->td_retval[0] = nerrors;
error = 0;
goto done;
}
error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td);
done:
kqueue_release(kq, 0);
done_norel:
if (fp != NULL)
fdrop(fp, td);
return (error);
}
int
kqueue_add_filteropts(int filt, struct filterops *filtops)
{
int error;
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 (0);
}
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;
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;
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_aquire) 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;
int error, filt, event;
int haskqglobal;
fp = NULL;
kn = NULL;
error = 0;
haskqglobal = 0;
filt = kev->filter;
fops = kqueue_fo_find(filt);
if (fops == NULL)
return EINVAL;
tkn = knote_alloc(waitok); /* prevent waiting with locks */
findkn:
if (fops->f_isfd) {
KASSERT(td != NULL, ("td is NULL"));
error = fget(td, kev->ident, &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 inteligence 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;
}
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 (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 stablize. */
if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
if (fp != NULL) {
fdrop(fp, td);
fp = NULL;
}
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
goto findkn;
}
if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
KQ_UNLOCK(kq);
error = ENOENT;
goto done;
}
/*
* kn now contains the matching knote, or NULL if no match
*/
if (kev->flags & EV_ADD) {
if (kn == NULL) {
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);
kn->kn_status = KN_INFLUX|KN_DETACHED;
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(kn, td);
goto done;
}
KN_LIST_LOCK(kn);
} else {
/*
* 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_INFLUX;
KQ_UNLOCK(kq);
KN_LIST_LOCK(kn);
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
kn->kn_kevent.udata = kev->udata;
}
/*
* 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.
*/
event = kn->kn_fop->f_event(kn, 0);
KQ_LOCK(kq);
if (event)
KNOTE_ACTIVATE(kn, 1);
kn->kn_status &= ~KN_INFLUX;
KN_LIST_UNLOCK(kn);
} else if (kev->flags & EV_DELETE) {
kn->kn_status |= KN_INFLUX;
KQ_UNLOCK(kq);
if (!(kn->kn_status & KN_DETACHED))
kn->kn_fop->f_detach(kn);
knote_drop(kn, td);
goto done;
}
if ((kev->flags & EV_DISABLE) &&
((kn->kn_status & KN_DISABLED) == 0)) {
kn->kn_status |= KN_DISABLED;
}
if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
kn->kn_status &= ~KN_DISABLED;
if ((kn->kn_status & KN_ACTIVE) &&
((kn->kn_status & KN_QUEUED) == 0))
knote_enqueue(kn);
}
KQ_UNLOCK_FLUX(kq);
done:
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
if (fp != NULL)
fdrop(fp, td);
if (tkn != NULL)
knote_free(tkn);
if (fops != NULL)
kqueue_fo_release(filt);
return (error);
}
static int
kqueue_aquire(struct file *fp, struct kqueue **kqp)
{
int error;
struct kqueue *kq;
error = 0;
FILE_LOCK(fp);
do {
kq = fp->f_data;
if (fp->f_type != DTYPE_KQUEUE || kq == NULL) {
error = EBADF;
break;
}
*kqp = kq;
KQ_LOCK(kq);
if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
KQ_UNLOCK(kq);
error = EBADF;
break;
}
kq->kq_refcnt++;
KQ_UNLOCK(kq);
} while (0);
FILE_UNLOCK(fp);
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, &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;
u_long tmp_knhashmask;
int size;
int fd;
int mflag = waitok ? M_WAITOK : M_NOWAIT;
KQ_NOTOWNED(kq);
if (fops->f_isfd) {
fd = ident;
if (kq->kq_knlistsize <= fd) {
size = kq->kq_knlistsize;
while (size <= fd)
size += KQEXTENT;
MALLOC(list, struct klist *,
size * sizeof list, M_KQUEUE, mflag);
if (list == NULL)
return ENOMEM;
KQ_LOCK(kq);
if (kq->kq_knlistsize > fd) {
FREE(list, M_KQUEUE);
list = NULL;
} else {
if (kq->kq_knlist != NULL) {
bcopy(kq->kq_knlist, list,
kq->kq_knlistsize * sizeof list);
FREE(kq->kq_knlist, M_KQUEUE);
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 {
free(tmp_knhash, M_KQUEUE);
}
KQ_UNLOCK(kq);
}
}
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 INFLUX.
*/
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 timeval atv, rtv, ttv;
struct knote *kn, *marker;
int count, timeout, nkev, error;
int haskqglobal;
count = maxevents;
nkev = 0;
error = 0;
haskqglobal = 0;
if (maxevents == 0)
goto done_nl;
if (tsp != NULL) {
TIMESPEC_TO_TIMEVAL(&atv, tsp);
if (itimerfix(&atv)) {
error = EINVAL;
goto done_nl;
}
if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
timeout = -1;
else
timeout = atv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&atv);
getmicrouptime(&rtv);
timevaladd(&atv, &rtv);
} else {
atv.tv_sec = 0;
atv.tv_usec = 0;
timeout = 0;
}
marker = knote_alloc(1);
if (marker == NULL) {
error = ENOMEM;
goto done_nl;
}
marker->kn_status = KN_MARKER;
KQ_LOCK(kq);
goto start;
retry:
if (atv.tv_sec || atv.tv_usec) {
getmicrouptime(&rtv);
if (timevalcmp(&rtv, &atv, >=))
goto done;
ttv = atv;
timevalsub(&ttv, &rtv);
timeout = ttv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&ttv);
}
start:
kevp = keva;
if (kq->kq_count == 0) {
if (timeout < 0) {
error = EWOULDBLOCK;
} else {
kq->kq_state |= KQ_SLEEP;
error = msleep(kq, &kq->kq_lock, PSOCK | PCATCH,
"kqread", timeout);
}
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);
while (count) {
KQ_OWNED(kq);
kn = TAILQ_FIRST(&kq->kq_head);
if ((kn->kn_status == KN_MARKER && kn != marker) ||
(kn->kn_status & KN_INFLUX) == KN_INFLUX) {
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->kn_status & KN_INFLUX) == 0,
("KN_INFLUX set when not suppose to be"));
if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
kn->kn_status &= ~KN_QUEUED;
kn->kn_status |= KN_INFLUX;
kq->kq_count--;
KQ_UNLOCK(kq);
/*
* We don't need to lock the list since we've marked
* it _INFLUX.
*/
*kevp = kn->kn_kevent;
if (!(kn->kn_status & KN_DETACHED))
kn->kn_fop->f_detach(kn);
knote_drop(kn, td);
KQ_LOCK(kq);
kn = NULL;
} else {
kn->kn_status |= KN_INFLUX;
KQ_UNLOCK(kq);
if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
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_INFLUX);
kq->kq_count--;
KN_LIST_UNLOCK(kn);
continue;
}
*kevp = kn->kn_kevent;
KQ_LOCK(kq);
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
if (kn->kn_flags & EV_CLEAR) {
kn->kn_data = 0;
kn->kn_fflags = 0;
kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
kq->kq_count--;
} else
TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
kn->kn_status &= ~(KN_INFLUX);
KN_LIST_UNLOCK(kn);
}
/* we are returning a copy to the user */
kevp++;
nkev++;
count--;
if (nkev == KQ_NEVENTS) {
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);
}
/*
* XXX
* This could be expanded to call kqueue_scan, if desired.
*/
/*ARGSUSED*/
static int
kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
return (ENXIO);
}
/*ARGSUSED*/
static int
kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
return (ENXIO);
}
/*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_aquire(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);
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);
}
/*ARGSUSED*/
static int
kqueue_close(struct file *fp, struct thread *td)
{
struct kqueue *kq = fp->f_data;
struct filedesc *fdp;
struct knote *kn;
int i;
int error;
if ((error = kqueue_aquire(fp, &kq)))
return error;
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!"));
fdp = kq->kq_fdp;
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) {
KASSERT((kn->kn_status & KN_INFLUX) == 0,
("KN_INFLUX set when not suppose to be"));
kn->kn_status |= KN_INFLUX;
KQ_UNLOCK(kq);
if (!(kn->kn_status & KN_DETACHED))
kn->kn_fop->f_detach(kn);
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) {
KASSERT((kn->kn_status & KN_INFLUX) == 0,
("KN_INFLUX set when not suppose to be"));
kn->kn_status |= KN_INFLUX;
KQ_UNLOCK(kq);
if (!(kn->kn_status & KN_DETACHED))
kn->kn_fop->f_detach(kn);
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) {
kq->kq_state &= ~KQ_SEL;
selwakeuppri(&kq->kq_sel, PSOCK);
}
KQ_UNLOCK(kq);
FILEDESC_LOCK_FAST(fdp);
SLIST_REMOVE(&fdp->fd_kqlist, kq, kqueue, kq_list);
FILEDESC_UNLOCK_FAST(fdp);
knlist_destroy(&kq->kq_sel.si_note);
mtx_destroy(&kq->kq_lock);
kq->kq_fdp = NULL;
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);
free(kq, M_KQUEUE);
fp->f_data = NULL;
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) {
kq->kq_state &= ~KQ_SEL;
selwakeuppri(&kq->kq_sel, PSOCK);
}
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 islocked)
{
struct kqueue *kq;
struct knote *kn;
if (list == NULL)
return;
KNL_ASSERT_LOCK(list, islocked);
if (!islocked)
list->kl_lock(list->kl_lockarg);
/*
* If we unlock the list lock (and set KN_INFLUX), we can eliminate
* the kqueue scheduling, but this will introduce four
* lock/unlock's for each knote to test. If we do, continue to use
* SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is
* only safe if you want to remove the current item, which we are
* not doing.
*/
SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
kq = kn->kn_kq;
if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) {
KQ_LOCK(kq);
if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) {
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);
}
kq = NULL;
}
if (!islocked)
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->kn_status & (KN_INFLUX|KN_DETACHED)) ==
(KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED"));
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);
if (!kqislocked)
KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX,
("knlist_remove called w/o knote being KN_INFLUX or already removed"));
if (!knlislocked)
knl->kl_lock(knl->kl_lockarg);
SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
kn->kn_knlist = NULL;
if (!knlislocked)
knl->kl_unlock(knl->kl_lockarg);
if (!kqislocked)
KQ_LOCK(kn->kn_kq);
kn->kn_status |= KN_DETACHED;
if (!kqislocked)
KQ_UNLOCK(kn->kn_kq);
}
/*
* remove all knotes from a specified klist
*/
void
knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
{
knlist_remove_kq(knl, kn, islocked, 0);
}
/*
* remove knote from a specified klist while in f_event handler.
*/
void
knlist_remove_inevent(struct knlist *knl, struct knote *kn)
{
knlist_remove_kq(knl, kn, 1,
(kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK);
}
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 int knlist_mtx_locked(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 int
knlist_mtx_locked(void *arg)
{
return (mtx_owned((struct mtx *)arg));
}
void
knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
void (*kl_unlock)(void *), int (*kl_locked)(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_locked == NULL)
knl->kl_locked = knlist_mtx_locked;
else
knl->kl_locked = kl_locked;
SLIST_INIT(&knl->kl_list);
}
void
knlist_destroy(struct knlist *knl)
{
#ifdef INVARIANTS
/*
* if we run across this error, we need to find the offending
* driver and have it call knlist_clear.
*/
if (!SLIST_EMPTY(&knl->kl_list))
printf("WARNING: destroying knlist w/ knotes on it!\n");
#endif
knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL;
SLIST_INIT(&knl->kl_list);
}
/*
* 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;
if (islocked)
KNL_ASSERT_LOCKED(knl);
else {
KNL_ASSERT_UNLOCKED(knl);
again: /* need to reaquire 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->kn_status & KN_INFLUX)) {
KQ_UNLOCK(kq);
continue;
}
knlist_remove_kq(knl, kn, 1, 1);
if (killkn) {
kn->kn_status |= KN_INFLUX | KN_DETACHED;
KQ_UNLOCK(kq);
knote_drop(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 KN_INFLUX remaining */
kn = SLIST_FIRST(&knl->kl_list);
kq = kn->kn_kq;
KQ_LOCK(kq);
KASSERT(kn->kn_status & KN_INFLUX,
("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_LOCK_ASSERT(fdp, MA_OWNED);
/*
* We shouldn't have to worry about new kevents appearing on fd
* since filedesc is locked.
*/
SLIST_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->kn_status & KN_INFLUX) {
/* 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->kn_status |= KN_INFLUX;
KQ_UNLOCK(kq);
if (!(kn->kn_status & KN_DETACHED))
kn->kn_fop->f_detach(kn);
knote_drop(kn, td);
influx = 1;
KQ_LOCK(kq);
}
KQ_UNLOCK_FLUX(kq);
}
}
static int
knote_attach(struct knote *kn, struct kqueue *kq)
{
struct klist *list;
KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX"));
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;
}
/*
* knote must already have been detached using the f_detach method.
* no lock need to be held, it is assumed that the KN_INFLUX flag is set
* to prevent other removal.
*/
static void
knote_drop(struct knote *kn, struct thread *td)
{
struct kqueue *kq;
struct klist *list;
kq = kn->kn_kq;
KQ_NOTOWNED(kq);
KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX,
("knote_drop called without KN_INFLUX set in kn_status"));
KQ_LOCK(kq);
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 ((struct knote *)uma_zalloc(knote_zone,
(waitok ? M_WAITOK : M_NOWAIT)|M_ZERO));
}
static void
knote_free(struct knote *kn)
{
if (kn != NULL)
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;
int error;
if ((error = fget(td, fd, &fp)) != 0)
return (error);
if ((error = kqueue_aquire(fp, &kq)) != 0)
goto noaquire;
error = kqueue_register(kq, kev, td, waitok);
kqueue_release(kq, 0);
noaquire:
fdrop(fp, td);
return error;
}
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