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NetBSD/sys/kern/kern_event.c

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/* $NetBSD: kern_event.c,v 1.5 2002/11/26 18:44:34 christos Exp $ */
/*-
* 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.
*
* $FreeBSD: src/sys/kern/kern_event.c,v 1.27 2001/07/05 17:10:44 rwatson Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/unistd.h>
#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/select.h>
#include <sys/queue.h>
#include <sys/event.h>
#include <sys/eventvar.h>
#include <sys/poll.h>
#include <sys/pool.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <sys/mount.h>
#include <sys/filedesc.h>
#include <sys/syscallargs.h>
static int kqueue_scan(struct file *fp, size_t maxevents,
struct kevent *ulistp, const struct timespec *timeout,
struct proc *p, register_t *retval);
static void kqueue_wakeup(struct kqueue *kq);
static int kqueue_read(struct file *fp, off_t *offset, struct uio *uio,
struct ucred *cred, int flags);
static int kqueue_write(struct file *fp, off_t *offset, struct uio *uio,
struct ucred *cred, int flags);
static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
struct proc *p);
static int kqueue_fcntl(struct file *fp, u_int com, caddr_t data,
struct proc *p);
static int kqueue_poll(struct file *fp, int events, struct proc *p);
static int kqueue_kqfilter(struct file *fp, struct knote *kn);
static int kqueue_stat(struct file *fp, struct stat *sp, struct proc *p);
static int kqueue_close(struct file *fp, struct proc *p);
static struct fileops kqueueops = {
kqueue_read, kqueue_write, kqueue_ioctl, kqueue_fcntl, kqueue_poll,
kqueue_stat, kqueue_close, kqueue_kqfilter
};
static void knote_attach(struct knote *kn, struct filedesc *fdp);
static void knote_drop(struct knote *kn, struct proc *p,
struct filedesc *fdp);
static void knote_enqueue(struct knote *kn);
static void knote_dequeue(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 const struct filterops kqread_filtops =
{ 1, NULL, filt_kqdetach, filt_kqueue };
static const struct filterops proc_filtops =
{ 0, filt_procattach, filt_procdetach, filt_proc };
static const struct filterops file_filtops =
{ 1, filt_fileattach, NULL, NULL };
struct pool kqueue_pool;
struct pool knote_pool;
#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))
extern const struct filterops sig_filtops;
/*
* Table for for all system-defined filters.
* These should be listed in the numeric order of the EVFILT_* defines.
* If filtops is NULL, the filter isn't implemented in NetBSD.
* End of list is when name is NULL.
*/
struct kfilter {
const char *name; /* name of filter */
uint32_t filter; /* id of filter */
const struct filterops *filtops;/* operations for filter */
};
/* System defined filters */
static const struct kfilter sys_kfilters[] = {
{ "EVFILT_READ", EVFILT_READ, &file_filtops },
{ "EVFILT_WRITE", EVFILT_WRITE, &file_filtops },
{ "EVFILT_AIO", EVFILT_AIO, NULL },
{ "EVFILT_VNODE", EVFILT_VNODE, &file_filtops },
{ "EVFILT_PROC", EVFILT_PROC, &proc_filtops },
{ "EVFILT_SIGNAL", EVFILT_SIGNAL, &sig_filtops },
{ NULL, 0, NULL }, /* end of list */
};
/* User defined kfilters */
static struct kfilter *user_kfilters; /* array */
static int user_kfilterc; /* current offset */
static int user_kfiltermaxc; /* max size so far */
/*
* kqueue_init:
*
* Initialize the kqueue/knote facility.
*/
void
kqueue_init(void)
{
pool_init(&kqueue_pool, sizeof(struct kqueue), 0, 0, 0, "kqueuepl",
NULL);
pool_init(&knote_pool, sizeof(struct knote), 0, 0, 0, "knotepl",
NULL);
}
/*
* Find kfilter entry by name, or NULL if not found.
*/
static const struct kfilter *
kfilter_byname_sys(const char *name)
{
int i;
for (i = 0; sys_kfilters[i].name != NULL; i++) {
if (strcmp(name, sys_kfilters[i].name) == 0)
return (&sys_kfilters[i]);
}
return (NULL);
}
static struct kfilter *
kfilter_byname_user(const char *name)
{
int i;
/* user_kfilters[] could be NULL if no filters were registered */
if (!user_kfilters)
return (NULL);
for (i = 0; user_kfilters[i].name != NULL; i++) {
if (user_kfilters[i].name != '\0' &&
strcmp(name, user_kfilters[i].name) == 0)
return (&user_kfilters[i]);
}
return (NULL);
}
static const struct kfilter *
kfilter_byname(const char *name)
{
const struct kfilter *kfilter;
if ((kfilter = kfilter_byname_sys(name)) != NULL)
return (kfilter);
return (kfilter_byname_user(name));
}
/*
* Find kfilter entry by filter id, or NULL if not found.
* Assumes entries are indexed in filter id order, for speed.
*/
static const struct kfilter *
kfilter_byfilter(uint32_t filter)
{
const struct kfilter *kfilter;
if (filter < EVFILT_SYSCOUNT) /* it's a system filter */
kfilter = &sys_kfilters[filter];
else if (user_kfilters != NULL &&
filter < EVFILT_SYSCOUNT + user_kfilterc)
/* it's a user filter */
kfilter = &user_kfilters[filter - EVFILT_SYSCOUNT];
else
return (NULL); /* out of range */
KASSERT(kfilter->filter == filter); /* sanity check! */
return (kfilter);
}
/*
* Register a new kfilter. Stores the entry in user_kfilters.
* Returns 0 if operation succeeded, or an appropriate errno(2) otherwise.
* If retfilter != NULL, the new filterid is returned in it.
*/
int
kfilter_register(const char *name, const struct filterops *filtops,
int *retfilter)
{
struct kfilter *kfilter;
void *space;
int len;
if (name == NULL || name[0] == '\0' || filtops == NULL)
return (EINVAL); /* invalid args */
if (kfilter_byname(name) != NULL)
return (EEXIST); /* already exists */
if (user_kfilterc > 0xffffffff - EVFILT_SYSCOUNT)
return (EINVAL); /* too many */
/* check if need to grow user_kfilters */
if (user_kfilterc + 1 > user_kfiltermaxc) {
/*
* Grow in KFILTER_EXTENT chunks. Use malloc(9), because we
* want to traverse user_kfilters as an array.
*/
user_kfiltermaxc += KFILTER_EXTENT;
kfilter = malloc(user_kfiltermaxc * sizeof(struct filter *),
M_KEVENT, M_WAITOK);
/* copy existing user_kfilters */
if (user_kfilters != NULL)
memcpy((caddr_t)kfilter, (caddr_t)user_kfilters,
user_kfilterc * sizeof(struct kfilter *));
/* zero new sections */
memset((caddr_t)kfilter +
user_kfilterc * sizeof(struct kfilter *), 0,
(user_kfiltermaxc - user_kfilterc) *
sizeof(struct kfilter *));
/* switch to new kfilter */
if (user_kfilters != NULL)
free(user_kfilters, M_KEVENT);
user_kfilters = kfilter;
}
len = strlen(name) + 1; /* copy name */
space = malloc(len, M_KEVENT, M_WAITOK);
memcpy(space, name, len);
user_kfilters[user_kfilterc].name = space;
user_kfilters[user_kfilterc].filter = user_kfilterc + EVFILT_SYSCOUNT;
len = sizeof(struct filterops); /* copy filtops */
space = malloc(len, M_KEVENT, M_WAITOK);
memcpy(space, filtops, len);
user_kfilters[user_kfilterc].filtops = space;
if (retfilter != NULL)
*retfilter = user_kfilters[user_kfilterc].filter;
user_kfilterc++; /* finally, increment count */
return (0);
}
/*
* Unregister a kfilter previously registered with kfilter_register.
* This retains the filter id, but clears the name and frees filtops (filter
* operations), so that the number isn't reused during a boot.
* Returns 0 if operation succeeded, or an appropriate errno(2) otherwise.
*/
int
kfilter_unregister(const char *name)
{
struct kfilter *kfilter;
if (name == NULL || name[0] == '\0')
return (EINVAL); /* invalid name */
if (kfilter_byname_sys(name) != NULL)
return (EINVAL); /* can't detach system filters */
kfilter = kfilter_byname_user(name);
if (kfilter == NULL) /* not found */
return (ENOENT);
if (kfilter->name[0] != '\0') {
/* XXX Cast away const (but we know it's safe. */
free((void *) kfilter->name, M_KEVENT);
kfilter->name = ""; /* mark as `not implemented' */
}
if (kfilter->filtops != NULL) {
/* XXX Cast away const (but we know it's safe. */
free((void *) kfilter->filtops, M_KEVENT);
kfilter->filtops = NULL; /* mark as `not implemented' */
}
return (0);
}
/*
* Filter attach method for EVFILT_READ and EVFILT_WRITE on normal file
* descriptors. Calls struct fileops kqfilter method for given file descriptor.
*/
static int
filt_fileattach(struct knote *kn)
{
struct file *fp;
fp = kn->kn_fp;
return ((*fp->f_ops->fo_kqfilter)(fp, kn));
}
/*
* Filter detach method for EVFILT_READ on kqueue descriptor.
*/
static void
filt_kqdetach(struct knote *kn)
{
struct kqueue *kq;
kq = (struct kqueue *)kn->kn_fp->f_data;
SLIST_REMOVE(&kq->kq_sel.sel_klist, kn, knote, kn_selnext);
}
/*
* Filter event method for EVFILT_READ on kqueue descriptor.
*/
/*ARGSUSED*/
static int
filt_kqueue(struct knote *kn, long hint)
{
struct kqueue *kq;
kq = (struct kqueue *)kn->kn_fp->f_data;
kn->kn_data = kq->kq_count;
return (kn->kn_data > 0);
}
/*
* Filter attach method for EVFILT_PROC.
*/
static int
filt_procattach(struct knote *kn)
{
struct proc *p;
p = pfind(kn->kn_id);
if (p == NULL)
return (ESRCH);
/*
* Fail if it's not owned by you, or the last exec gave us
* setuid/setgid privs (unless you're root).
*/
if ((p->p_cred->p_ruid != curproc->p_cred->p_ruid ||
(p->p_flag & P_SUGID))
&& suser(curproc->p_ucred, &curproc->p_acflag) != 0)
return (EACCES);
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;
}
/* XXXSMP lock the process? */
SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
return (0);
}
/*
* Filter detach method for EVFILT_PROC.
*
* 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 might not exist any more.
*/
static void
filt_procdetach(struct knote *kn)
{
struct proc *p;
if (kn->kn_status & KN_DETACHED)
return;
p = kn->kn_ptr.p_proc;
KASSERT(p->p_stat == SDEAD || pfind(kn->kn_id) == p);
/* XXXSMP lock the process? */
SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
}
/*
* Filter event method for EVFILT_PROC.
*/
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) {
/*
* Detach the knote from watched process and mark
* it as such. We can't leave this to kqueue_scan(),
* since the process might not exist by then. And we
* have to do this now, since psignal KNOTE() is called
* also for zombies and we might end up reading freed
* memory if the kevent would already be picked up
* and knote g/c'ed.
*/
kn->kn_fop->f_detach(kn);
kn->kn_status |= KN_DETACHED;
/* Mark as ONESHOT, so that the knote it g/c'ed when read */
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);
}
/*
* filt_seltrue:
*
* This filter "event" routine simulates seltrue().
*/
int
filt_seltrue(struct knote *kn, long hint)
{
/*
* We don't know how much data can be read/written,
* but we know that it *can* be. This is about as
* good as select/poll does as well.
*/
kn->kn_data = 0;
return (1);
}
/*
* This provides full kqfilter entry for device switch tables, which
* has same effect as filter using filt_seltrue() as filter method.
*/
static void
filt_seltruedetach(struct knote *kn)
{
/* Nothing to do */
}
static const struct filterops seltrue_filtops =
{ 1, NULL, filt_seltruedetach, filt_seltrue };
int
seltrue_kqfilter(dev_t dev, struct knote *kn)
{
switch (kn->kn_filter) {
case EVFILT_READ:
case EVFILT_WRITE:
kn->kn_fop = &seltrue_filtops;
break;
default:
return (1);
}
/* Nothing more to do */
return (0);
}
/*
* kqueue(2) system call.
*/
int
sys_kqueue(struct proc *p, void *v, register_t *retval)
{
struct filedesc *fdp;
struct kqueue *kq;
struct file *fp;
int fd, error;
fdp = p->p_fd;
error = falloc(p, &fp, &fd); /* setup a new file descriptor */
if (error)
return (error);
fp->f_flag = FREAD | FWRITE;
fp->f_type = DTYPE_KQUEUE;
fp->f_ops = &kqueueops;
kq = pool_get(&kqueue_pool, PR_WAITOK);
memset((char *)kq, 0, sizeof(struct kqueue));
TAILQ_INIT(&kq->kq_head);
fp->f_data = (caddr_t)kq; /* store the kqueue with the fp */
*retval = fd;
if (fdp->fd_knlistsize < 0)
fdp->fd_knlistsize = 0; /* this process has a kq */
kq->kq_fdp = fdp;
FILE_SET_MATURE(fp);
FILE_UNUSE(fp, p); /* falloc() does FILE_USE() */
return (error);
}
/*
* kevent(2) system call.
*/
int
sys_kevent(struct proc *p, void *v, register_t *retval)
{
struct sys_kevent_args /* {
syscallarg(int) fd;
syscallarg(const struct kevent *) changelist;
syscallarg(size_t) nchanges;
syscallarg(struct kevent *) eventlist;
syscallarg(size_t) nevents;
syscallarg(const struct timespec *) timeout;
} */ *uap = v;
struct kevent *kevp;
struct kqueue *kq;
struct file *fp;
struct timespec ts;
size_t i, n;
int nerrors, error;
/* check that we're dealing with a kq */
fp = fd_getfile(p->p_fd, SCARG(uap, fd));
if (!fp || fp->f_type != DTYPE_KQUEUE)
return (EBADF);
FILE_USE(fp);
if (SCARG(uap, timeout) != NULL) {
error = copyin(SCARG(uap, timeout), &ts, sizeof(ts));
if (error)
goto done;
SCARG(uap, timeout) = &ts;
}
kq = (struct kqueue *)fp->f_data;
nerrors = 0;
/* traverse list of events to register */
while (SCARG(uap, nchanges) > 0) {
/* copyin a maximum of KQ_EVENTS at each pass */
n = MIN(SCARG(uap, nchanges), KQ_NEVENTS);
error = copyin(SCARG(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;
/* register each knote */
error = kqueue_register(kq, kevp, p);
if (error) {
if (SCARG(uap, nevents) != 0) {
kevp->flags = EV_ERROR;
kevp->data = error;
error = copyout((caddr_t)kevp,
(caddr_t)SCARG(uap, eventlist),
sizeof(*kevp));
if (error)
goto done;
SCARG(uap, eventlist)++;
SCARG(uap, nevents)--;
nerrors++;
} else {
goto done;
}
}
}
SCARG(uap, nchanges) -= n; /* update the results */
SCARG(uap, changelist) += n;
}
if (nerrors) {
*retval = nerrors;
error = 0;
goto done;
}
/* actually scan through the events */
error = kqueue_scan(fp, SCARG(uap, nevents), SCARG(uap, eventlist),
SCARG(uap, timeout), p, retval);
done:
FILE_UNUSE(fp, p);
return (error);
}
/*
* Register a given kevent kev onto the kqueue
*/
int
kqueue_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
{
const struct kfilter *kfilter;
struct filedesc *fdp;
struct file *fp;
struct knote *kn;
int s, error;
fdp = kq->kq_fdp;
fp = NULL;
kn = NULL;
error = 0;
kfilter = kfilter_byfilter(kev->filter);
if (kfilter == NULL || kfilter->filtops == NULL) {
/* filter not found nor implemented */
return (EINVAL);
}
/* search if knote already exists */
if (kfilter->filtops->f_isfd) {
/* monitoring a file descriptor */
if ((fp = fd_getfile(fdp, kev->ident)) == NULL)
return (EBADF); /* validate descriptor */
FILE_USE(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 {
/*
* not monitoring a file descriptor, so
* lookup knotes in internal hash table
*/
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;
}
}
if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
error = ENOENT; /* filter not found */
goto done;
}
/*
* kn now contains the matching knote, or NULL if no match
*/
if (kev->flags & EV_ADD) {
/* add knote */
if (kn == NULL) {
/* create new knote */
kn = pool_get(&knote_pool, PR_WAITOK);
if (kn == NULL) {
error = ENOMEM;
goto done;
}
kn->kn_fp = fp;
kn->kn_kq = kq;
kn->kn_fop = kfilter->filtops;
/*
* 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 = kfilter->filtops->f_attach(kn)) != 0) {
knote_drop(kn, p, fdp);
goto done;
}
} else {
/* modify existing knote */
/*
* The user may change some filter values after the
* initial EV_ADD, but doing so will not reset any
* filter which have already been triggered.
*/
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
kn->kn_kevent.udata = kev->udata;
}
s = splhigh();
if (kn->kn_fop->f_event(kn, 0))
KNOTE_ACTIVATE(kn);
splx(s);
} else if (kev->flags & EV_DELETE) { /* delete knote */
kn->kn_fop->f_detach(kn);
knote_drop(kn, p, fdp);
goto done;
}
/* disable knote */
if ((kev->flags & EV_DISABLE) &&
((kn->kn_status & KN_DISABLED) == 0)) {
s = splhigh();
kn->kn_status |= KN_DISABLED;
splx(s);
}
/* enable knote */
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)
FILE_UNUSE(fp, p);
return (error);
}
/*
* Scan through the list of events on fp (for a maximum of maxevents),
* returning the results in to ulistp. Timeout is determined by tsp; if
* NULL, wait indefinitely, if 0 valued, perform a poll, otherwise wait
* as appropriate.
*/
static int
kqueue_scan(struct file *fp, size_t maxevents, struct kevent *ulistp,
const struct timespec *tsp, struct proc *p, register_t *retval)
{
struct kqueue *kq;
struct kevent *kevp;
struct timeval atv;
struct knote *kn, marker;
size_t count, nkev;
int s, timeout, error;
kq = (struct kqueue *)fp->f_data;
count = maxevents;
nkev = error = 0;
if (count == 0)
goto done;
if (tsp != NULL) { /* timeout supplied */
TIMESPEC_TO_TIMEVAL(&atv, tsp);
if (itimerfix(&atv)) {
error = EINVAL;
goto done;
}
s = splclock();
timeradd(&atv, &time, &atv); /* calc. time to wait until */
splx(s);
if (tsp->tv_sec == 0 && tsp->tv_nsec < 1000 /*<1us*/)
timeout = -1; /* perform a poll */
else
timeout = hzto(&atv); /* calculate hz till timeout */
} else {
atv.tv_sec = 0; /* no timeout, wait forever */
atv.tv_usec = 0;
timeout = 0;
}
goto start;
retry:
if (atv.tv_sec || atv.tv_usec) { /* timeout requested */
s = splclock();
if (timercmp(&time, &atv, >=)) {
splx(s);
goto done; /* timeout reached */
}
splx(s);
timeout = hzto(&atv); /* recalc. timeout remaining */
}
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;
}
/* mark end of knote list */
TAILQ_INSERT_TAIL(&kq->kq_head, &marker, kn_tqe);
while (count) { /* while user wants data ... */
kn = TAILQ_FIRST(&kq->kq_head); /* get next knote */
TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
if (kn == &marker) { /* if it's our marker, stop */
splx(s);
if (count == maxevents)
goto retry;
goto done;
}
if (kn->kn_status & KN_DISABLED) {
/* don't want disabled events */
kn->kn_status &= ~KN_QUEUED;
kq->kq_count--;
continue;
}
if ((kn->kn_flags & EV_ONESHOT) == 0 &&
kn->kn_fop->f_event(kn, 0) == 0) {
/*
* non-ONESHOT event that hasn't
* triggered again, so de-queue.
*/
kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
kq->kq_count--;
continue;
}
*kevp = kn->kn_kevent;
kevp++;
nkev++;
if (kn->kn_flags & EV_ONESHOT) {
/* delete ONESHOT events after retrieval */
kn->kn_status &= ~KN_QUEUED;
kq->kq_count--;
splx(s);
kn->kn_fop->f_detach(kn);
knote_drop(kn, p, p->p_fd);
s = splhigh();
} else if (kn->kn_flags & EV_CLEAR) {
/* clear state after retrieval */
kn->kn_data = 0;
kn->kn_fflags = 0;
kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
kq->kq_count--;
} else {
/* add event back on list */
TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
}
count--;
if (nkev == KQ_NEVENTS) {
/* do copyouts in KQ_NEVENTS chunks */
splx(s);
error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
sizeof(struct kevent) * nkev);
ulistp += nkev;
nkev = 0;
kevp = kq->kq_kev;
s = splhigh();
if (error)
break;
}
}
/* remove marker */
TAILQ_REMOVE(&kq->kq_head, &marker, kn_tqe);
splx(s);
done:
if (nkev != 0) {
/* copyout remaining events */
error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
sizeof(struct kevent) * nkev);
}
*retval = maxevents - count;
return (error);
}
/*
* struct fileops read method for a kqueue descriptor.
* Not implemented.
* XXX: This could be expanded to call kqueue_scan, if desired.
*/
/*ARGSUSED*/
static int
kqueue_read(struct file *fp, off_t *offset, struct uio *uio,
struct ucred *cred, int flags)
{
return (ENXIO);
}
/*
* struct fileops write method for a kqueue descriptor.
* Not implemented.
*/
/*ARGSUSED*/
static int
kqueue_write(struct file *fp, off_t *offset, struct uio *uio,
struct ucred *cred, int flags)
{
return (ENXIO);
}
/*
* struct fileops ioctl method for a kqueue descriptor.
*
* Two ioctls are currently supported. They both use struct kfilter_mapping:
* KFILTER_BYNAME find name for filter, and return result in
* name, which is of size len.
* KFILTER_BYFILTER find filter for name. len is ignored.
*/
/*ARGSUSED*/
static int
kqueue_ioctl(struct file *fp, u_long com, caddr_t data, struct proc *p)
{
struct kfilter_mapping *km;
const struct kfilter *kfilter;
char *name;
int error;
km = (struct kfilter_mapping *)data;
error = 0;
switch (com) {
case KFILTER_BYFILTER: /* convert filter -> name */
kfilter = kfilter_byfilter(km->filter);
if (kfilter != NULL)
error = copyoutstr(kfilter->name, km->name, km->len,
NULL);
else
error = ENOENT;
break;
case KFILTER_BYNAME: /* convert name -> filter */
MALLOC(name, char *, KFILTER_MAXNAME, M_KEVENT, M_WAITOK);
error = copyinstr(km->name, name, KFILTER_MAXNAME, NULL);
if (error) {
FREE(name, M_KEVENT);
break;
}
kfilter = kfilter_byname(name);
if (kfilter != NULL)
km->filter = kfilter->filter;
else
error = ENOENT;
FREE(name, M_KEVENT);
break;
default:
error = ENOTTY;
}
return (error);
}
/*
* struct fileops fcntl method for a kqueue descriptor.
* Not implemented.
*/
/*ARGSUSED*/
static int
kqueue_fcntl(struct file *fp, u_int com, caddr_t data, struct proc *p)
{
return (ENOTTY);
}
/*
* struct fileops poll method for a kqueue descriptor.
* Determine if kqueue has events pending.
*/
static int
kqueue_poll(struct file *fp, int events, struct proc *p)
{
struct kqueue *kq;
int revents;
kq = (struct kqueue *)fp->f_data;
revents = 0;
if (events & (POLLIN | POLLRDNORM)) {
if (kq->kq_count) {
revents |= events & (POLLIN | POLLRDNORM);
} else {
selrecord(p, &kq->kq_sel);
}
}
return (revents);
}
/*
* struct fileops stat method for a kqueue descriptor.
* Returns dummy info, with st_size being number of events pending.
*/
static int
kqueue_stat(struct file *fp, struct stat *st, struct proc *p)
{
struct kqueue *kq;
kq = (struct kqueue *)fp->f_data;
memset((void *)st, 0, sizeof(*st));
st->st_size = kq->kq_count;
st->st_blksize = sizeof(struct kevent);
st->st_mode = S_IFIFO;
return (0);
}
/*
* struct fileops close method for a kqueue descriptor.
* Cleans up kqueue.
*/
static int
kqueue_close(struct file *fp, struct proc *p)
{
struct kqueue *kq;
struct filedesc *fdp;
struct knote **knp, *kn, *kn0;
int i;
kq = (struct kqueue *)fp->f_data;
fdp = p->p_fd;
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);
FILE_UNUSE(kn->kn_fp, p);
pool_put(&knote_pool, kn);
*knp = kn0;
} 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);
/* XXX non-fd release of kn->kn_ptr */
pool_put(&knote_pool, kn);
*knp = kn0;
} else {
knp = &SLIST_NEXT(kn, kn_link);
}
kn = kn0;
}
}
}
pool_put(&kqueue_pool, kq);
fp->f_data = NULL;
return (0);
}
/*
* wakeup a kqueue
*/
static void
kqueue_wakeup(struct kqueue *kq)
{
if (kq->kq_state & KQ_SLEEP) { /* if currently sleeping ... */
kq->kq_state &= ~KQ_SLEEP;
wakeup(kq); /* ... wakeup */
}
/* Notify select/poll and kevent. */
selnotify(&kq->kq_sel, 0);
}
/*
* struct fileops kqfilter method for a kqueue descriptor.
* Event triggered when monitored kqueue changes.
*/
/*ARGSUSED*/
static int
kqueue_kqfilter(struct file *fp, struct knote *kn)
{
struct kqueue *kq;
KASSERT(fp == kn->kn_fp);
kq = (struct kqueue *)kn->kn_fp->f_data;
if (kn->kn_filter != EVFILT_READ)
return (1);
kn->kn_fop = &kqread_filtops;
SLIST_INSERT_HEAD(&kq->kq_sel.sel_klist, kn, kn_selnext);
return (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 proc *p, struct klist *list)
{
struct knote *kn;
while ((kn = SLIST_FIRST(list)) != NULL) {
kn->kn_fop->f_detach(kn);
knote_drop(kn, p, p->p_fd);
}
}
/*
* Remove all knotes referencing a specified fd
*/
void
knote_fdclose(struct proc *p, int fd)
{
struct filedesc *fdp;
struct klist *list;
fdp = p->p_fd;
list = &fdp->fd_knlist[fd];
knote_remove(p, list);
}
/*
* Attach a new knote to a file descriptor
*/
static void
knote_attach(struct knote *kn, struct filedesc *fdp)
{
struct klist *list;
int size;
if (! kn->kn_fop->f_isfd) {
/* if knote is not on an fd, store on internal hash table */
if (fdp->fd_knhashmask == 0)
fdp->fd_knhash = hashinit(KN_HASHSIZE, HASH_LIST,
M_KEVENT, M_WAITOK, &fdp->fd_knhashmask);
list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
goto done;
}
/*
* otherwise, knote is on an fd.
* knotes are stored in fd_knlist indexed by kn->kn_id.
*/
if (fdp->fd_knlistsize <= kn->kn_id) {
/* expand list, it's too small */
size = fdp->fd_knlistsize;
while (size <= kn->kn_id) {
/* grow in KQ_EXTENT chunks */
size += KQ_EXTENT;
}
list = malloc(size * sizeof(struct klist *), M_KEVENT,M_WAITOK);
if (fdp->fd_knlist) {
/* copy existing knlist */
memcpy((caddr_t)list, (caddr_t)fdp->fd_knlist,
fdp->fd_knlistsize * sizeof(struct klist *));
}
/*
* Zero new memory. Stylistically, SLIST_INIT() should be
* used here, but that does same thing as the memset() anyway.
*/
memset(&list[fdp->fd_knlistsize], 0,
(size - fdp->fd_knlistsize) * sizeof(struct klist *));
/* switch to new knlist */
if (fdp->fd_knlist != NULL)
free(fdp->fd_knlist, M_KEVENT);
fdp->fd_knlistsize = size;
fdp->fd_knlist = list;
}
/* get list head for this fd */
list = &fdp->fd_knlist[kn->kn_id];
done:
/* add new knote */
SLIST_INSERT_HEAD(list, kn, kn_link);
kn->kn_status = 0;
}
/*
* Drop knote.
* Should be called at spl == 0, since we don't want to hold spl
* while calling FILE_UNUSE and free.
*/
static void
knote_drop(struct knote *kn, struct proc *p, struct filedesc *fdp)
{
struct klist *list;
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)];
SLIST_REMOVE(list, kn, knote, kn_link);
if (kn->kn_status & KN_QUEUED)
knote_dequeue(kn);
if (kn->kn_fop->f_isfd)
FILE_UNUSE(kn->kn_fp, p);
pool_put(&knote_pool, kn);
}
/*
* Queue new event for knote.
*/
static void
knote_enqueue(struct knote *kn)
{
struct kqueue *kq;
int s;
kq = kn->kn_kq;
s = splhigh();
KASSERT((kn->kn_status & KN_QUEUED) == 0);
TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
kn->kn_status |= KN_QUEUED;
kq->kq_count++;
splx(s);
kqueue_wakeup(kq);
}
/*
* Dequeue event for knote.
*/
static void
knote_dequeue(struct knote *kn)
{
struct kqueue *kq;
int s;
kq = kn->kn_kq;
s = splhigh();
KASSERT(kn->kn_status & KN_QUEUED);
TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
kn->kn_status &= ~KN_QUEUED;
kq->kq_count--;
splx(s);
}
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