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freebsd-dev/sys/kern/kern_event.c
Robert Watson a6719c82b1 Push Giant acquisition down into fo_stat() from most callers. Acquire 
Giant conditional on debug.mpsafenet in the socket soo_stat() routine,
unconditionally in vn_statfile() for VFS, and otherwise don't acquire
Giant.  Accept an unlocked read in kqueue_stat(), and cryptof_stat() is
a no-op.  Don't acquire Giant in fstat() system call.

Note: in fdescfs, fo_stat() is called while holding Giant due to the VFS
stack sitting on top, and therefore there will still be Giant recursion
in this case.
2004-07-22 20:40:23 +00:00

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/*-
* Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@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 <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/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/uio.h>
#include <vm/uma.h>
MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
static int kqueue_scan(struct file *fp, int maxevents,
struct kevent *ulistp, const struct timespec *timeout,
struct thread *td);
static void kqueue_wakeup(struct kqueue *kq);
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 void knote_attach(struct knote *kn, struct filedesc *fdp);
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(void);
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 };
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");
#define KNOTE_ACTIVATE(kn) do { \
kn->kn_status |= KN_ACTIVE; \
if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
knote_enqueue(kn); \
} while(0)
#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 };
extern struct filterops sig_filtops;
extern struct filterops fs_filtops;
/*
* Table for for all system-defined filters.
*/
static struct filterops *sysfilt_ops[] = {
&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 */
};
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 (1);
kn->kn_fop = &kqread_filtops;
SLIST_INSERT_HEAD(&kq->kq_sel.si_note, kn, kn_selnext);
return (0);
}
static void
filt_kqdetach(struct knote *kn)
{
struct kqueue *kq = kn->kn_fp->f_data;
SLIST_REMOVE(&kq->kq_sel.si_note, kn, knote, kn_selnext);
}
/*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);
}
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;
}
if (p == NULL)
return (ESRCH);
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
*/
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)
SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
/*
* 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);
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.
*/
static void
filt_procdetach(struct knote *kn)
{
struct proc *p = kn->kn_ptr.p_proc;
if (kn->kn_status & KN_DETACHED)
return;
PROC_LOCK(p);
SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
PROC_UNLOCK(p);
}
static int
filt_proc(struct knote *kn, long hint)
{
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) {
kn->kn_status |= KN_DETACHED;
kn->kn_flags |= (EV_EOF | EV_ONESHOT);
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);
if (error)
kn->kn_fflags |= NOTE_TRACKERR;
}
return (kn->kn_fflags != 0);
}
static void
filt_timerexpire(void *knx)
{
struct knote *kn = knx;
struct callout *calloutp;
struct timeval tv;
int tticks;
kn->kn_data++;
KNOTE_ACTIVATE(kn);
if ((kn->kn_flags & EV_ONESHOT) == 0) {
tv.tv_sec = kn->kn_sdata / 1000;
tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
tticks = tvtohz(&tv);
calloutp = (struct callout *)kn->kn_hook;
callout_reset(calloutp, tticks, filt_timerexpire, kn);
}
}
/*
* data contains amount of time to sleep, in milliseconds
*/
static int
filt_timerattach(struct knote *kn)
{
struct callout *calloutp;
struct timeval tv;
int tticks;
if (kq_ncallouts >= kq_calloutmax)
return (ENOMEM);
kq_ncallouts++;
tv.tv_sec = kn->kn_sdata / 1000;
tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
tticks = tvtohz(&tv);
kn->kn_flags |= EV_CLEAR; /* automatically set */
MALLOC(calloutp, struct callout *, sizeof(*calloutp),
M_KQUEUE, M_WAITOK);
callout_init(calloutp, 0);
kn->kn_hook = calloutp;
callout_reset(calloutp, tticks, filt_timerexpire, kn);
return (0);
}
static void
filt_timerdetach(struct knote *kn)
{
struct callout *calloutp;
calloutp = (struct callout *)kn->kn_hook;
callout_drain(calloutp);
FREE(calloutp, M_KQUEUE);
kq_ncallouts--;
}
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;
mtx_lock(&Giant);
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(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
TAILQ_INIT(&kq->kq_head);
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);
FILEDESC_LOCK(fdp);
td->td_retval[0] = fd;
if (fdp->fd_knlistsize < 0)
fdp->fd_knlistsize = 0; /* this process has a kq */
FILEDESC_UNLOCK(fdp);
kq->kq_fdp = fdp;
done2:
mtx_unlock(&Giant);
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 kevent *kevp;
struct kqueue *kq;
struct file *fp;
struct timespec ts;
int i, n, nerrors, error;
if ((error = fget(td, uap->fd, &fp)) != 0)
return (error);
if (fp->f_type != DTYPE_KQUEUE) {
fdrop(fp, td);
return (EBADF);
}
if (uap->timeout != NULL) {
error = copyin(uap->timeout, &ts, sizeof(ts));
if (error)
goto done_nogiant;
uap->timeout = &ts;
}
mtx_lock(&Giant);
kq = fp->f_data;
nerrors = 0;
while (uap->nchanges > 0) {
n = uap->nchanges > KQ_NEVENTS ? KQ_NEVENTS : uap->nchanges;
error = copyin(uap->changelist, kq->kq_kev,
n * sizeof(struct kevent));
if (error)
goto done;
for (i = 0; i < n; i++) {
kevp = &kq->kq_kev[i];
kevp->flags &= ~EV_SYSFLAGS;
error = kqueue_register(kq, kevp, td);
if (error) {
if (uap->nevents != 0) {
kevp->flags = EV_ERROR;
kevp->data = error;
(void) copyout(kevp,
uap->eventlist,
sizeof(*kevp));
uap->eventlist++;
uap->nevents--;
nerrors++;
} else {
goto done;
}
}
}
uap->nchanges -= n;
uap->changelist += n;
}
if (nerrors) {
td->td_retval[0] = nerrors;
error = 0;
goto done;
}
error = kqueue_scan(fp, uap->nevents, uap->eventlist, uap->timeout, td);
done:
mtx_unlock(&Giant);
done_nogiant:
if (fp != NULL)
fdrop(fp, td);
return (error);
}
int
kqueue_add_filteropts(int filt, struct filterops *filtops)
{
if (filt > 0)
panic("filt(%d) > 0", filt);
if (filt + EVFILT_SYSCOUNT < 0)
panic("filt(%d) + EVFILT_SYSCOUNT(%d) == %d < 0",
filt, EVFILT_SYSCOUNT, filt + EVFILT_SYSCOUNT);
if (sysfilt_ops[~filt] != &null_filtops)
panic("sysfilt_ops[~filt(%d)] != &null_filtops", filt);
sysfilt_ops[~filt] = filtops;
return (0);
}
int
kqueue_del_filteropts(int filt)
{
if (filt > 0)
panic("filt(%d) > 0", filt);
if (filt + EVFILT_SYSCOUNT < 0)
panic("filt(%d) + EVFILT_SYSCOUNT(%d) == %d < 0",
filt, EVFILT_SYSCOUNT, filt + EVFILT_SYSCOUNT);
if (sysfilt_ops[~filt] == &null_filtops)
panic("sysfilt_ops[~filt(%d)] != &null_filtops", filt);
sysfilt_ops[~filt] = &null_filtops;
return (0);
}
int
kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td)
{
struct filedesc *fdp = kq->kq_fdp;
struct filterops *fops;
struct file *fp = NULL;
struct knote *kn = NULL;
int s, error = 0;
if (kev->filter < 0) {
if (kev->filter + EVFILT_SYSCOUNT < 0)
return (EINVAL);
fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
} else {
/*
* XXX
* filter attach routine is responsible for insuring that
* the identifier can be attached to it.
*/
printf("unknown filter: %d\n", kev->filter);
return (EINVAL);
}
FILEDESC_LOCK(fdp);
if (fops->f_isfd) {
/* validate descriptor */
if ((u_int)kev->ident >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[kev->ident]) == NULL) {
FILEDESC_UNLOCK(fdp);
return (EBADF);
}
fhold(fp);
if (kev->ident < fdp->fd_knlistsize) {
SLIST_FOREACH(kn, &fdp->fd_knlist[kev->ident], kn_link)
if (kq == kn->kn_kq &&
kev->filter == kn->kn_filter)
break;
}
} else {
if (fdp->fd_knhashmask != 0) {
struct klist *list;
list = &fdp->fd_knhash[
KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)];
SLIST_FOREACH(kn, list, kn_link)
if (kev->ident == kn->kn_id &&
kq == kn->kn_kq &&
kev->filter == kn->kn_filter)
break;
}
}
FILEDESC_UNLOCK(fdp);
if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
error = ENOENT;
goto done;
}
/*
* kn now contains the matching knote, or NULL if no match
*/
if (kev->flags & EV_ADD) {
if (kn == NULL) {
kn = knote_alloc();
if (kn == NULL) {
error = ENOMEM;
goto done;
}
kn->kn_fp = fp;
kn->kn_kq = kq;
kn->kn_fop = fops;
/*
* apply reference count to knote structure, and
* do not release it at the end of this routine.
*/
fp = NULL;
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
kev->fflags = 0;
kev->data = 0;
kn->kn_kevent = *kev;
knote_attach(kn, fdp);
if ((error = fops->f_attach(kn)) != 0) {
knote_drop(kn, td);
goto done;
}
} 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_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
kn->kn_kevent.udata = kev->udata;
}
s = splhigh();
if (kn->kn_fop->f_event(kn, 0))
KNOTE_ACTIVATE(kn);
splx(s);
} else if (kev->flags & EV_DELETE) {
kn->kn_fop->f_detach(kn);
knote_drop(kn, td);
goto done;
}
if ((kev->flags & EV_DISABLE) &&
((kn->kn_status & KN_DISABLED) == 0)) {
s = splhigh();
kn->kn_status |= KN_DISABLED;
splx(s);
}
if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
s = splhigh();
kn->kn_status &= ~KN_DISABLED;
if ((kn->kn_status & KN_ACTIVE) &&
((kn->kn_status & KN_QUEUED) == 0))
knote_enqueue(kn);
splx(s);
}
done:
if (fp != NULL)
fdrop(fp, td);
return (error);
}
static int
kqueue_scan(struct file *fp, int maxevents, struct kevent *ulistp,
const struct timespec *tsp, struct thread *td)
{
struct kqueue *kq;
struct kevent *kevp;
struct timeval atv, rtv, ttv;
struct knote *kn, marker;
int s, count, timeout, nkev = 0, error = 0;
FILE_LOCK_ASSERT(fp, MA_NOTOWNED);
kq = fp->f_data;
count = maxevents;
if (count == 0)
goto done;
if (tsp != NULL) {
TIMESPEC_TO_TIMEVAL(&atv, tsp);
if (itimerfix(&atv)) {
error = EINVAL;
goto done;
}
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;
}
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 = kq->kq_kev;
s = splhigh();
if (kq->kq_count == 0) {
if (timeout < 0) {
error = EWOULDBLOCK;
} else {
kq->kq_state |= KQ_SLEEP;
error = tsleep(kq, PSOCK | PCATCH, "kqread", timeout);
}
splx(s);
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) {
kn = TAILQ_FIRST(&kq->kq_head);
TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
if (kn == &marker) {
splx(s);
if (count == maxevents)
goto retry;
goto done;
}
if (kn->kn_status & KN_DISABLED) {
kn->kn_status &= ~KN_QUEUED;
kq->kq_count--;
continue;
}
if ((kn->kn_flags & EV_ONESHOT) == 0 &&
kn->kn_fop->f_event(kn, 0) == 0) {
kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
kq->kq_count--;
continue;
}
*kevp = kn->kn_kevent;
kevp++;
nkev++;
if (kn->kn_flags & EV_ONESHOT) {
kn->kn_status &= ~KN_QUEUED;
kq->kq_count--;
splx(s);
kn->kn_fop->f_detach(kn);
knote_drop(kn, td);
s = splhigh();
} else 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);
}
count--;
if (nkev == KQ_NEVENTS) {
splx(s);
error = copyout(&kq->kq_kev, ulistp,
sizeof(struct kevent) * nkev);
ulistp += nkev;
nkev = 0;
kevp = kq->kq_kev;
s = splhigh();
if (error)
break;
}
}
TAILQ_REMOVE(&kq->kq_head, &marker, kn_tqe);
splx(s);
done:
if (nkev != 0)
error = copyout(&kq->kq_kev, ulistp,
sizeof(struct kevent) * 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 s = splnet();
kq = fp->f_data;
if (events & (POLLIN | POLLRDNORM)) {
if (kq->kq_count) {
revents |= events & (POLLIN | POLLRDNORM);
} else {
selrecord(td, &kq->kq_sel);
kq->kq_state |= KQ_SEL;
}
}
splx(s);
return (revents);
}
/*ARGSUSED*/
static int
kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
struct thread *td)
{
struct kqueue *kq;
/* Unlocked read. */
kq = fp->f_data;
bzero((void *)st, sizeof(*st));
st->st_size = kq->kq_count;
st->st_blksize = sizeof(struct kevent);
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 = kq->kq_fdp;
struct knote **knp, *kn, *kn0;
int i;
mtx_lock(&Giant);
FILEDESC_LOCK(fdp);
for (i = 0; i < fdp->fd_knlistsize; i++) {
knp = &SLIST_FIRST(&fdp->fd_knlist[i]);
kn = *knp;
while (kn != NULL) {
kn0 = SLIST_NEXT(kn, kn_link);
if (kq == kn->kn_kq) {
kn->kn_fop->f_detach(kn);
*knp = kn0;
FILE_LOCK(kn->kn_fp);
FILEDESC_UNLOCK(fdp);
fdrop_locked(kn->kn_fp, td);
knote_free(kn);
FILEDESC_LOCK(fdp);
} else {
knp = &SLIST_NEXT(kn, kn_link);
}
kn = kn0;
}
}
if (fdp->fd_knhashmask != 0) {
for (i = 0; i < fdp->fd_knhashmask + 1; i++) {
knp = &SLIST_FIRST(&fdp->fd_knhash[i]);
kn = *knp;
while (kn != NULL) {
kn0 = SLIST_NEXT(kn, kn_link);
if (kq == kn->kn_kq) {
kn->kn_fop->f_detach(kn);
*knp = kn0;
/* XXX non-fd release of kn->kn_ptr */
FILEDESC_UNLOCK(fdp);
knote_free(kn);
FILEDESC_LOCK(fdp);
} else {
knp = &SLIST_NEXT(kn, kn_link);
}
kn = kn0;
}
}
}
FILEDESC_UNLOCK(fdp);
if (kq->kq_state & KQ_SEL) {
kq->kq_state &= ~KQ_SEL;
selwakeuppri(&kq->kq_sel, PSOCK);
}
funsetown(&kq->kq_sigio);
free(kq, M_KQUEUE);
fp->f_data = NULL;
mtx_unlock(&Giant);
return (0);
}
static void
kqueue_wakeup(struct kqueue *kq)
{
if (kq->kq_state & KQ_SLEEP) {
kq->kq_state &= ~KQ_SLEEP;
wakeup(kq);
}
if (kq->kq_state & KQ_SEL) {
kq->kq_state &= ~KQ_SEL;
selwakeuppri(&kq->kq_sel, PSOCK);
}
if (kq->kq_state & KQ_ASYNC) {
pgsigio(&kq->kq_sigio, SIGIO, 0);
}
KNOTE(&kq->kq_sel.si_note, 0);
}
/*
* walk down a list of knotes, activating them if their event has triggered.
*/
void
knote(struct klist *list, long hint)
{
struct knote *kn;
SLIST_FOREACH(kn, list, kn_selnext)
if (kn->kn_fop->f_event(kn, hint))
KNOTE_ACTIVATE(kn);
}
/*
* remove all knotes from a specified klist
*/
void
knote_remove(struct thread *td, struct klist *list)
{
struct knote *kn;
while ((kn = SLIST_FIRST(list)) != NULL) {
kn->kn_fop->f_detach(kn);
knote_drop(kn, td);
}
}
/*
* remove all knotes referencing a specified fd
*/
void
knote_fdclose(struct thread *td, int fd)
{
struct filedesc *fdp = td->td_proc->p_fd;
struct klist *list;
FILEDESC_LOCK(fdp);
list = &fdp->fd_knlist[fd];
FILEDESC_UNLOCK(fdp);
knote_remove(td, list);
}
static void
knote_attach(struct knote *kn, struct filedesc *fdp)
{
struct klist *list, *tmp_knhash;
u_long tmp_knhashmask;
int size;
FILEDESC_LOCK(fdp);
if (! kn->kn_fop->f_isfd) {
if (fdp->fd_knhashmask == 0) {
FILEDESC_UNLOCK(fdp);
tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
&tmp_knhashmask);
FILEDESC_LOCK(fdp);
if (fdp->fd_knhashmask == 0) {
fdp->fd_knhash = tmp_knhash;
fdp->fd_knhashmask = tmp_knhashmask;
} else {
free(tmp_knhash, M_KQUEUE);
}
}
list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
goto done;
}
if (fdp->fd_knlistsize <= kn->kn_id) {
size = fdp->fd_knlistsize;
while (size <= kn->kn_id)
size += KQEXTENT;
FILEDESC_UNLOCK(fdp);
MALLOC(list, struct klist *,
size * sizeof(struct klist *), M_KQUEUE, M_WAITOK);
FILEDESC_LOCK(fdp);
if (fdp->fd_knlistsize > kn->kn_id) {
FREE(list, M_KQUEUE);
goto bigenough;
}
if (fdp->fd_knlist != NULL) {
bcopy(fdp->fd_knlist, list,
fdp->fd_knlistsize * sizeof(struct klist *));
FREE(fdp->fd_knlist, M_KQUEUE);
}
bzero((caddr_t)list +
fdp->fd_knlistsize * sizeof(struct klist *),
(size - fdp->fd_knlistsize) * sizeof(struct klist *));
fdp->fd_knlistsize = size;
fdp->fd_knlist = list;
}
bigenough:
list = &fdp->fd_knlist[kn->kn_id];
done:
FILEDESC_UNLOCK(fdp);
SLIST_INSERT_HEAD(list, kn, kn_link);
kn->kn_status = 0;
}
/*
* should be called at spl == 0, since we don't want to hold spl
* while calling fdrop and free.
*/
static void
knote_drop(struct knote *kn, struct thread *td)
{
struct filedesc *fdp = td->td_proc->p_fd;
struct klist *list;
FILEDESC_LOCK(fdp);
if (kn->kn_fop->f_isfd)
list = &fdp->fd_knlist[kn->kn_id];
else
list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
if (kn->kn_fop->f_isfd)
FILE_LOCK(kn->kn_fp);
FILEDESC_UNLOCK(fdp);
SLIST_REMOVE(list, kn, knote, kn_link);
if (kn->kn_status & KN_QUEUED)
knote_dequeue(kn);
if (kn->kn_fop->f_isfd)
fdrop_locked(kn->kn_fp, td);
knote_free(kn);
}
static void
knote_enqueue(struct knote *kn)
{
struct kqueue *kq = kn->kn_kq;
int s = splhigh();
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++;
splx(s);
kqueue_wakeup(kq);
}
static void
knote_dequeue(struct knote *kn)
{
struct kqueue *kq = kn->kn_kq;
int s = splhigh();
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--;
splx(s);
}
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(void)
{
return ((struct knote *)uma_zalloc(knote_zone, M_WAITOK));
}
static void
knote_free(struct knote *kn)
{
uma_zfree(knote_zone, kn);
}
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