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/* $NetBSD: kern_event.c,v 1.105 2019/10/18 19:43:49 christos Exp $ */
/*-
* Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Andrew Doran.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*-
* 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_event.c,v 1.105 2019/10/18 19:43:49 christos Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/wait.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/select.h>
#include <sys/queue.h>
#include <sys/event.h>
#include <sys/eventvar.h>
#include <sys/poll.h>
#include <sys/kmem.h>
#include <sys/stat.h>
#include <sys/filedesc.h>
#include <sys/syscallargs.h>
#include <sys/kauth.h>
#include <sys/conf.h>
#include <sys/atomic.h>
static int kqueue_scan(file_t *, size_t, struct kevent *,
const struct timespec *, register_t *,
const struct kevent_ops *, struct kevent *,
size_t);
static int kqueue_ioctl(file_t *, u_long, void *);
static int kqueue_fcntl(file_t *, u_int, void *);
static int kqueue_poll(file_t *, int);
static int kqueue_kqfilter(file_t *, struct knote *);
static int kqueue_stat(file_t *, struct stat *);
static int kqueue_close(file_t *);
static int kqueue_register(struct kqueue *, struct kevent *);
static void kqueue_doclose(struct kqueue *, struct klist *, int);
static void knote_detach(struct knote *, filedesc_t *fdp, bool);
static void knote_enqueue(struct knote *);
static void knote_activate(struct knote *);
static void filt_kqdetach(struct knote *);
static int filt_kqueue(struct knote *, long hint);
static int filt_procattach(struct knote *);
static void filt_procdetach(struct knote *);
static int filt_proc(struct knote *, long hint);
static int filt_fileattach(struct knote *);
static void filt_timerexpire(void *x);
static int filt_timerattach(struct knote *);
static void filt_timerdetach(struct knote *);
static int filt_timer(struct knote *, long hint);
static int filt_fsattach(struct knote *kn);
static void filt_fsdetach(struct knote *kn);
static int filt_fs(struct knote *kn, long hint);
static const struct fileops kqueueops = {
.fo_name = "kqueue",
.fo_read = (void *)enxio,
.fo_write = (void *)enxio,
.fo_ioctl = kqueue_ioctl,
.fo_fcntl = kqueue_fcntl,
.fo_poll = kqueue_poll,
.fo_stat = kqueue_stat,
.fo_close = kqueue_close,
.fo_kqfilter = kqueue_kqfilter,
.fo_restart = fnullop_restart,
};
static const struct filterops kqread_filtops = {
.f_isfd = 1,
.f_attach = NULL,
.f_detach = filt_kqdetach,
.f_event = filt_kqueue,
};
static const struct filterops proc_filtops = {
.f_isfd = 0,
.f_attach = filt_procattach,
.f_detach = filt_procdetach,
.f_event = filt_proc,
};
static const struct filterops file_filtops = {
.f_isfd = 1,
.f_attach = filt_fileattach,
.f_detach = NULL,
.f_event = NULL,
};
static const struct filterops timer_filtops = {
.f_isfd = 0,
.f_attach = filt_timerattach,
.f_detach = filt_timerdetach,
.f_event = filt_timer,
};
static const struct filterops fs_filtops = {
.f_isfd = 0,
.f_attach = filt_fsattach,
.f_detach = filt_fsdetach,
.f_event = filt_fs,
};
static u_int kq_ncallouts = 0;
static int kq_calloutmax = (4 * 1024);
#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.
*
* Note that 'refcnt' is meaningless for built-in filters.
*/
struct kfilter {
const char *name; /* name of filter */
uint32_t filter; /* id of filter */
unsigned refcnt; /* reference count */
const struct filterops *filtops;/* operations for filter */
size_t namelen; /* length of name string */
};
/* System defined filters */
static struct kfilter sys_kfilters[] = {
{ "EVFILT_READ", EVFILT_READ, 0, &file_filtops, 0 },
{ "EVFILT_WRITE", EVFILT_WRITE, 0, &file_filtops, 0, },
{ "EVFILT_AIO", EVFILT_AIO, 0, NULL, 0 },
{ "EVFILT_VNODE", EVFILT_VNODE, 0, &file_filtops, 0 },
{ "EVFILT_PROC", EVFILT_PROC, 0, &proc_filtops, 0 },
{ "EVFILT_SIGNAL", EVFILT_SIGNAL, 0, &sig_filtops, 0 },
{ "EVFILT_TIMER", EVFILT_TIMER, 0, &timer_filtops, 0 },
{ "EVFILT_FS", EVFILT_FS, 0, &fs_filtops, 0 },
{ NULL, 0, 0, NULL, 0 },
};
/* User defined kfilters */
static struct kfilter *user_kfilters; /* array */
static int user_kfilterc; /* current offset */
static int user_kfiltermaxc; /* max size so far */
static size_t user_kfiltersz; /* size of allocated memory */
/*
* Global Locks.
*
* Lock order:
*
* kqueue_filter_lock
* -> kn_kq->kq_fdp->fd_lock
* -> object lock (e.g., device driver lock, kqueue_misc_lock, &c.)
* -> kn_kq->kq_lock
*
* Locking rules:
*
* f_attach: fdp->fd_lock, KERNEL_LOCK
* f_detach: fdp->fd_lock, KERNEL_LOCK
* f_event(!NOTE_SUBMIT) via kevent: fdp->fd_lock, _no_ object lock
* f_event via knote: whatever caller guarantees
* Typically, f_event(NOTE_SUBMIT) via knote: object lock
* f_event(!NOTE_SUBMIT) via knote: nothing,
* acquires/releases object lock inside.
*/
static krwlock_t kqueue_filter_lock; /* lock on filter lists */
static kmutex_t kqueue_misc_lock; /* miscellaneous */
static kauth_listener_t kqueue_listener;
static int
kqueue_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
void *arg0, void *arg1, void *arg2, void *arg3)
{
struct proc *p;
int result;
result = KAUTH_RESULT_DEFER;
p = arg0;
if (action != KAUTH_PROCESS_KEVENT_FILTER)
return result;
if ((kauth_cred_getuid(p->p_cred) != kauth_cred_getuid(cred) ||
ISSET(p->p_flag, PK_SUGID)))
return result;
result = KAUTH_RESULT_ALLOW;
return result;
}
/*
* Initialize the kqueue subsystem.
*/
void
kqueue_init(void)
{
rw_init(&kqueue_filter_lock);
mutex_init(&kqueue_misc_lock, MUTEX_DEFAULT, IPL_NONE);
kqueue_listener = kauth_listen_scope(KAUTH_SCOPE_PROCESS,
kqueue_listener_cb, NULL);
}
/*
* Find kfilter entry by name, or NULL if not found.
*/
static struct kfilter *
kfilter_byname_sys(const char *name)
{
int i;
KASSERT(rw_lock_held(&kqueue_filter_lock));
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;
KASSERT(rw_lock_held(&kqueue_filter_lock));
/* user filter slots have a NULL name if previously deregistered */
for (i = 0; i < user_kfilterc ; i++) {
if (user_kfilters[i].name != NULL &&
strcmp(name, user_kfilters[i].name) == 0)
return &user_kfilters[i];
}
return NULL;
}
static struct kfilter *
kfilter_byname(const char *name)
{
struct kfilter *kfilter;
KASSERT(rw_lock_held(&kqueue_filter_lock));
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 struct kfilter *
kfilter_byfilter(uint32_t filter)
{
struct kfilter *kfilter;
KASSERT(rw_lock_held(&kqueue_filter_lock));
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;
size_t len;
int i;
if (name == NULL || name[0] == '\0' || filtops == NULL)
return (EINVAL); /* invalid args */
rw_enter(&kqueue_filter_lock, RW_WRITER);
if (kfilter_byname(name) != NULL) {
rw_exit(&kqueue_filter_lock);
return (EEXIST); /* already exists */
}
if (user_kfilterc > 0xffffffff - EVFILT_SYSCOUNT) {
rw_exit(&kqueue_filter_lock);
return (EINVAL); /* too many */
}
for (i = 0; i < user_kfilterc; i++) {
kfilter = &user_kfilters[i];
if (kfilter->name == NULL) {
/* Previously deregistered slot. Reuse. */
goto reuse;
}
}
/* check if need to grow user_kfilters */
if (user_kfilterc + 1 > user_kfiltermaxc) {
/* Grow in KFILTER_EXTENT chunks. */
user_kfiltermaxc += KFILTER_EXTENT;
len = user_kfiltermaxc * sizeof(*kfilter);
kfilter = kmem_alloc(len, KM_SLEEP);
memset((char *)kfilter + user_kfiltersz, 0, len - user_kfiltersz);
if (user_kfilters != NULL) {
memcpy(kfilter, user_kfilters, user_kfiltersz);
kmem_free(user_kfilters, user_kfiltersz);
}
user_kfiltersz = len;
user_kfilters = kfilter;
}
/* Adding new slot */
kfilter = &user_kfilters[user_kfilterc++];
reuse:
kfilter->name = kmem_strdupsize(name, &kfilter->namelen, KM_SLEEP);
kfilter->filter = (kfilter - user_kfilters) + EVFILT_SYSCOUNT;
kfilter->filtops = kmem_alloc(sizeof(*filtops), KM_SLEEP);
memcpy(__UNCONST(kfilter->filtops), filtops, sizeof(*filtops));
if (retfilter != NULL)
*retfilter = kfilter->filter;
rw_exit(&kqueue_filter_lock);
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 */
rw_enter(&kqueue_filter_lock, RW_WRITER);
if (kfilter_byname_sys(name) != NULL) {
rw_exit(&kqueue_filter_lock);
return (EINVAL); /* can't detach system filters */
}
kfilter = kfilter_byname_user(name);
if (kfilter == NULL) {
rw_exit(&kqueue_filter_lock);
return (ENOENT);
}
if (kfilter->refcnt != 0) {
rw_exit(&kqueue_filter_lock);
return (EBUSY);
}
/* Cast away const (but we know it's safe. */
kmem_free(__UNCONST(kfilter->name), kfilter->namelen);
kfilter->name = NULL; /* mark as `not implemented' */
if (kfilter->filtops != NULL) {
/* Cast away const (but we know it's safe. */
kmem_free(__UNCONST(kfilter->filtops),
sizeof(*kfilter->filtops));
kfilter->filtops = NULL; /* mark as `not implemented' */
}
rw_exit(&kqueue_filter_lock);
return (0);
}
/*
* Filter attach method for EVFILT_READ and EVFILT_WRITE on normal file
* descriptors. Calls fileops kqfilter method for given file descriptor.
*/
static int
filt_fileattach(struct knote *kn)
{
file_t *fp;
fp = kn->kn_obj;
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 = ((file_t *)kn->kn_obj)->f_kqueue;
mutex_spin_enter(&kq->kq_lock);
SLIST_REMOVE(&kq->kq_sel.sel_klist, kn, knote, kn_selnext);
mutex_spin_exit(&kq->kq_lock);
}
/*
* Filter event method for EVFILT_READ on kqueue descriptor.
*/
/*ARGSUSED*/
static int
filt_kqueue(struct knote *kn, long hint)
{
struct kqueue *kq;
int rv;
kq = ((file_t *)kn->kn_obj)->f_kqueue;
if (hint != NOTE_SUBMIT)
mutex_spin_enter(&kq->kq_lock);
kn->kn_data = kq->kq_count;
rv = (kn->kn_data > 0);
if (hint != NOTE_SUBMIT)
mutex_spin_exit(&kq->kq_lock);
return rv;
}
/*
* Filter attach method for EVFILT_PROC.
*/
static int
filt_procattach(struct knote *kn)
{
struct proc *p;
struct lwp *curl;
curl = curlwp;
mutex_enter(proc_lock);
if (kn->kn_flags & EV_FLAG1) {
/*
* NOTE_TRACK attaches to the child process too early
* for proc_find, so do a raw look up and check the state
* explicitly.
*/
p = proc_find_raw(kn->kn_id);
if (p != NULL && p->p_stat != SIDL)
p = NULL;
} else {
p = proc_find(kn->kn_id);
}
if (p == NULL) {
mutex_exit(proc_lock);
return ESRCH;
}
/*
* Fail if it's not owned by you, or the last exec gave us
* setuid/setgid privs (unless you're root).
*/
mutex_enter(p->p_lock);
mutex_exit(proc_lock);
if (kauth_authorize_process(curl->l_cred, KAUTH_PROCESS_KEVENT_FILTER,
p, NULL, NULL, NULL) != 0) {
mutex_exit(p->p_lock);
return EACCES;
}
kn->kn_obj = 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;
}
SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
mutex_exit(p->p_lock);
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_obj;
mutex_enter(p->p_lock);
SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
mutex_exit(p->p_lock);
}
/*
* Filter event method for EVFILT_PROC.
*/
static int
filt_proc(struct knote *kn, long hint)
{
u_int event, fflag;
struct kevent kev;
struct kqueue *kq;
int error;
event = (u_int)hint & NOTE_PCTRLMASK;
kq = kn->kn_kq;
fflag = 0;
/* If the user is interested in this event, record it. */
if (kn->kn_sfflags & event)
fflag |= event;
if (event == NOTE_EXIT) {
struct proc *p = kn->kn_obj;
if (p != NULL)
kn->kn_data = P_WAITSTATUS(p);
/*
* Process is gone, so flag the event as finished.
*
* 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.
*/
filt_procdetach(kn);
mutex_spin_enter(&kq->kq_lock);
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);
kn->kn_fflags |= fflag;
mutex_spin_exit(&kq->kq_lock);
return 1;
}
mutex_spin_enter(&kq->kq_lock);
if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
/*
* 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. Register knote with new
* process.
*/
memset(&kev, 0, sizeof(kev));
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 */
mutex_spin_exit(&kq->kq_lock);
error = kqueue_register(kq, &kev);
mutex_spin_enter(&kq->kq_lock);
if (error != 0)
kn->kn_fflags |= NOTE_TRACKERR;
}
kn->kn_fflags |= fflag;
fflag = kn->kn_fflags;
mutex_spin_exit(&kq->kq_lock);
return fflag != 0;
}
static void
filt_timerexpire(void *knx)
{
struct knote *kn = knx;
int tticks;
mutex_enter(&kqueue_misc_lock);
kn->kn_data++;
knote_activate(kn);
if ((kn->kn_flags & EV_ONESHOT) == 0) {
tticks = mstohz(kn->kn_sdata);
if (tticks <= 0)
tticks = 1;
callout_schedule((callout_t *)kn->kn_hook, tticks);
}
mutex_exit(&kqueue_misc_lock);
}
/*
* data contains amount of time to sleep, in milliseconds
*/
static int
filt_timerattach(struct knote *kn)
{
callout_t *calloutp;
struct kqueue *kq;
int tticks;
tticks = mstohz(kn->kn_sdata);
/* if the supplied value is under our resolution, use 1 tick */
if (tticks == 0) {
if (kn->kn_sdata == 0)
return EINVAL;
tticks = 1;
}
if (atomic_inc_uint_nv(&kq_ncallouts) >= kq_calloutmax ||
(calloutp = kmem_alloc(sizeof(*calloutp), KM_NOSLEEP)) == NULL) {
atomic_dec_uint(&kq_ncallouts);
return ENOMEM;
}
callout_init(calloutp, CALLOUT_MPSAFE);
kq = kn->kn_kq;
mutex_spin_enter(&kq->kq_lock);
kn->kn_flags |= EV_CLEAR; /* automatically set */
kn->kn_hook = calloutp;
mutex_spin_exit(&kq->kq_lock);
callout_reset(calloutp, tticks, filt_timerexpire, kn);
return (0);
}
static void
filt_timerdetach(struct knote *kn)
{
callout_t *calloutp;
struct kqueue *kq = kn->kn_kq;
mutex_spin_enter(&kq->kq_lock);
/* prevent rescheduling when we expire */
kn->kn_flags |= EV_ONESHOT;
mutex_spin_exit(&kq->kq_lock);
calloutp = (callout_t *)kn->kn_hook;
callout_halt(calloutp, NULL);
callout_destroy(calloutp);
kmem_free(calloutp, sizeof(*calloutp));
atomic_dec_uint(&kq_ncallouts);
}
static int
filt_timer(struct knote *kn, long hint)
{
int rv;
mutex_enter(&kqueue_misc_lock);
rv = (kn->kn_data != 0);
mutex_exit(&kqueue_misc_lock);
return rv;
}
/*
* Filter event method for EVFILT_FS.
*/
struct klist fs_klist = SLIST_HEAD_INITIALIZER(&fs_klist);
static int
filt_fsattach(struct knote *kn)
{
mutex_enter(&kqueue_misc_lock);
kn->kn_flags |= EV_CLEAR;
SLIST_INSERT_HEAD(&fs_klist, kn, kn_selnext);
mutex_exit(&kqueue_misc_lock);
return 0;
}
static void
filt_fsdetach(struct knote *kn)
{
mutex_enter(&kqueue_misc_lock);
SLIST_REMOVE(&fs_klist, kn, knote, kn_selnext);
mutex_exit(&kqueue_misc_lock);
}
static int
filt_fs(struct knote *kn, long hint)
{
int rv;
mutex_enter(&kqueue_misc_lock);
kn->kn_fflags |= hint;
rv = (kn->kn_fflags != 0);
mutex_exit(&kqueue_misc_lock);
return rv;
}
/*
* 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 */
}
const struct filterops seltrue_filtops = {
.f_isfd = 1,
.f_attach = NULL,
.f_detach = filt_seltruedetach,
.f_event = 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 (EINVAL);
}
/* Nothing more to do */
return (0);
}
/*
* kqueue(2) system call.
*/
static int
kqueue1(struct lwp *l, int flags, register_t *retval)
{
struct kqueue *kq;
file_t *fp;
int fd, error;
if ((error = fd_allocfile(&fp, &fd)) != 0)
return error;
fp->f_flag = FREAD | FWRITE | (flags & (FNONBLOCK|FNOSIGPIPE));
fp->f_type = DTYPE_KQUEUE;
fp->f_ops = &kqueueops;
kq = kmem_zalloc(sizeof(*kq), KM_SLEEP);
mutex_init(&kq->kq_lock, MUTEX_DEFAULT, IPL_SCHED);
cv_init(&kq->kq_cv, "kqueue");
selinit(&kq->kq_sel);
TAILQ_INIT(&kq->kq_head);
fp->f_kqueue = kq;
*retval = fd;
kq->kq_fdp = curlwp->l_fd;
fd_set_exclose(l, fd, (flags & O_CLOEXEC) != 0);
fd_affix(curproc, fp, fd);
return error;
}
/*
* kqueue(2) system call.
*/
int
sys_kqueue(struct lwp *l, const void *v, register_t *retval)
{
return kqueue1(l, 0, retval);
}
int
sys_kqueue1(struct lwp *l, const struct sys_kqueue1_args *uap,
register_t *retval)
{
/* {
syscallarg(int) flags;
} */
return kqueue1(l, SCARG(uap, flags), retval);
}
/*
* kevent(2) system call.
*/
int
kevent_fetch_changes(void *ctx, const struct kevent *changelist,
struct kevent *changes, size_t index, int n)
{
return copyin(changelist + index, changes, n * sizeof(*changes));
}
int
kevent_put_events(void *ctx, struct kevent *events,
struct kevent *eventlist, size_t index, int n)
{
return copyout(events, eventlist + index, n * sizeof(*events));
}
static const struct kevent_ops kevent_native_ops = {
.keo_private = NULL,
.keo_fetch_timeout = copyin,
.keo_fetch_changes = kevent_fetch_changes,
.keo_put_events = kevent_put_events,
};
int
sys___kevent50(struct lwp *l, const struct sys___kevent50_args *uap,
register_t *retval)
{
/* {
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;
} */
return kevent1(retval, SCARG(uap, fd), SCARG(uap, changelist),
SCARG(uap, nchanges), SCARG(uap, eventlist), SCARG(uap, nevents),
SCARG(uap, timeout), &kevent_native_ops);
}
int
kevent1(register_t *retval, int fd,
const struct kevent *changelist, size_t nchanges,
struct kevent *eventlist, size_t nevents,
const struct timespec *timeout,
const struct kevent_ops *keops)
{
struct kevent *kevp;
struct kqueue *kq;
struct timespec ts;
size_t i, n, ichange;
int nerrors, error;
struct kevent kevbuf[KQ_NEVENTS]; /* approx 300 bytes on 64-bit */
file_t *fp;
/* check that we're dealing with a kq */
fp = fd_getfile(fd);
if (fp == NULL)
return (EBADF);
if (fp->f_type != DTYPE_KQUEUE) {
fd_putfile(fd);
return (EBADF);
}
if (timeout != NULL) {
error = (*keops->keo_fetch_timeout)(timeout, &ts, sizeof(ts));
if (error)
goto done;
timeout = &ts;
}
kq = fp->f_kqueue;
nerrors = 0;
ichange = 0;
/* traverse list of events to register */
while (nchanges > 0) {
n = MIN(nchanges, __arraycount(kevbuf));
error = (*keops->keo_fetch_changes)(keops->keo_private,
changelist, kevbuf, ichange, n);
if (error)
goto done;
for (i = 0; i < n; i++) {
kevp = &kevbuf[i];
kevp->flags &= ~EV_SYSFLAGS;
/* register each knote */
error = kqueue_register(kq, kevp);
if (!error && !(kevp->flags & EV_RECEIPT))
continue;
if (nevents == 0)
goto done;
kevp->flags = EV_ERROR;
kevp->data = error;
error = (*keops->keo_put_events)
(keops->keo_private, kevp,
eventlist, nerrors, 1);
if (error)
goto done;
nevents--;
nerrors++;
}
nchanges -= n; /* update the results */
ichange += n;
}
if (nerrors) {
*retval = nerrors;
error = 0;
goto done;
}
/* actually scan through the events */
error = kqueue_scan(fp, nevents, eventlist, timeout, retval, keops,
kevbuf, __arraycount(kevbuf));
done:
fd_putfile(fd);
return (error);
}
/*
* Register a given kevent kev onto the kqueue
*/
static int
kqueue_register(struct kqueue *kq, struct kevent *kev)
{
struct kfilter *kfilter;
filedesc_t *fdp;
file_t *fp;
fdfile_t *ff;
struct knote *kn, *newkn;
struct klist *list;
int error, fd, rv;
fdp = kq->kq_fdp;
fp = NULL;
kn = NULL;
error = 0;
fd = 0;
newkn = kmem_zalloc(sizeof(*newkn), KM_SLEEP);
rw_enter(&kqueue_filter_lock, RW_READER);
kfilter = kfilter_byfilter(kev->filter);
if (kfilter == NULL || kfilter->filtops == NULL) {
/* filter not found nor implemented */
rw_exit(&kqueue_filter_lock);
kmem_free(newkn, sizeof(*newkn));
return (EINVAL);
}
/* search if knote already exists */
if (kfilter->filtops->f_isfd) {
/* monitoring a file descriptor */
/* validate descriptor */
if (kev->ident > INT_MAX
|| (fp = fd_getfile(fd = kev->ident)) == NULL) {
rw_exit(&kqueue_filter_lock);
kmem_free(newkn, sizeof(*newkn));
return EBADF;
}
mutex_enter(&fdp->fd_lock);
ff = fdp->fd_dt->dt_ff[fd];
if (ff->ff_refcnt & FR_CLOSING) {
error = EBADF;
goto doneunlock;
}
if (fd <= fdp->fd_lastkqfile) {
SLIST_FOREACH(kn, &ff->ff_knlist, 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
*/
mutex_enter(&fdp->fd_lock);
if (fdp->fd_knhashmask != 0) {
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;
}
}
}
/*
* kn now contains the matching knote, or NULL if no match
*/
if (kev->flags & EV_ADD) {
if (kn == NULL) {
/* create new knote */
kn = newkn;
newkn = NULL;
kn->kn_obj = fp;
kn->kn_id = kev->ident;
kn->kn_kq = kq;
kn->kn_fop = kfilter->filtops;
kn->kn_kfilter = kfilter;
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
kev->fflags = 0;
kev->data = 0;
kn->kn_kevent = *kev;
KASSERT(kn->kn_fop != NULL);
/*
* apply reference count to knote structure, and
* do not release it at the end of this routine.
*/
fp = NULL;
if (!kn->kn_fop->f_isfd) {
/*
* If knote is not on an fd, store on
* internal hash table.
*/
if (fdp->fd_knhashmask == 0) {
/* XXXAD can block with fd_lock held */
fdp->fd_knhash = hashinit(KN_HASHSIZE,
HASH_LIST, true,
&fdp->fd_knhashmask);
}
list = &fdp->fd_knhash[KN_HASH(kn->kn_id,
fdp->fd_knhashmask)];
} else {
/* Otherwise, knote is on an fd. */
list = (struct klist *)
&fdp->fd_dt->dt_ff[kn->kn_id]->ff_knlist;
if ((int)kn->kn_id > fdp->fd_lastkqfile)
fdp->fd_lastkqfile = kn->kn_id;
}
SLIST_INSERT_HEAD(list, kn, kn_link);
KERNEL_LOCK(1, NULL); /* XXXSMP */
error = (*kfilter->filtops->f_attach)(kn);
KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */
if (error != 0) {
#ifdef DEBUG
struct proc *p = curlwp->l_proc;
const file_t *ft = kn->kn_obj;
printf("%s: %s[%d]: event type %d not "
"supported for file type %d/%s "
"(error %d)\n", __func__,
p->p_comm, p->p_pid,
kn->kn_filter, ft ? ft->f_type : -1,
ft ? ft->f_ops->fo_name : "?", error);
#endif
/* knote_detach() drops fdp->fd_lock */
knote_detach(kn, fdp, false);
goto done;
}
atomic_inc_uint(&kfilter->refcnt);
} else {
/*
* The user may change some filter values after the
* initial EV_ADD, but doing so will not reset any
* filter which have already been triggered.
*/
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
kn->kn_kevent.udata = kev->udata;
}
/*
* We can get here if we are trying to attach
* an event to a file descriptor that does not
* support events, and the attach routine is
* broken and does not return an error.
*/
KASSERT(kn->kn_fop != NULL);
KASSERT(kn->kn_fop->f_event != NULL);
KERNEL_LOCK(1, NULL); /* XXXSMP */
rv = (*kn->kn_fop->f_event)(kn, 0);
KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */
if (rv)
knote_activate(kn);
} else {
if (kn == NULL) {
error = ENOENT;
goto doneunlock;
}
if (kev->flags & EV_DELETE) {
/* knote_detach() drops fdp->fd_lock */
knote_detach(kn, fdp, true);
goto done;
}
}
/* disable knote */
if ((kev->flags & EV_DISABLE)) {
mutex_spin_enter(&kq->kq_lock);
if ((kn->kn_status & KN_DISABLED) == 0)
kn->kn_status |= KN_DISABLED;
mutex_spin_exit(&kq->kq_lock);
}
/* enable knote */
if ((kev->flags & EV_ENABLE)) {
knote_enqueue(kn);
}
doneunlock:
mutex_exit(&fdp->fd_lock);
done:
rw_exit(&kqueue_filter_lock);
if (newkn != NULL)
kmem_free(newkn, sizeof(*newkn));
if (fp != NULL)
fd_putfile(fd);
return (error);
}
#if defined(DEBUG)
#define KN_FMT(buf, kn) \
(snprintb((buf), sizeof(buf), __KN_FLAG_BITS, (kn)->kn_status), buf)
static void
kqueue_check(const char *func, size_t line, const struct kqueue *kq)
{
const struct knote *kn;
int count;
int nmarker;
char buf[128];
KASSERT(mutex_owned(&kq->kq_lock));
KASSERT(kq->kq_count >= 0);
count = 0;
nmarker = 0;
TAILQ_FOREACH(kn, &kq->kq_head, kn_tqe) {
if ((kn->kn_status & (KN_MARKER | KN_QUEUED)) == 0) {
panic("%s,%zu: kq=%p kn=%p !(MARKER|QUEUED) %s",
func, line, kq, kn, KN_FMT(buf, kn));
}
if ((kn->kn_status & KN_MARKER) == 0) {
if (kn->kn_kq != kq) {
panic("%s,%zu: kq=%p kn(%p) != kn->kq(%p): %s",
func, line, kq, kn, kn->kn_kq,
KN_FMT(buf, kn));
}
if ((kn->kn_status & KN_ACTIVE) == 0) {
panic("%s,%zu: kq=%p kn=%p: !ACTIVE %s",
func, line, kq, kn, KN_FMT(buf, kn));
}
count++;
if (count > kq->kq_count) {
goto bad;
}
} else {
nmarker++;
#if 0
if (nmarker > 10000) {
panic("%s,%zu: kq=%p too many markers: "
"%d != %d, nmarker=%d",
func, line, kq, kq->kq_count, count,
nmarker);
}
#endif
}
}
if (kq->kq_count != count) {
bad:
panic("%s,%zu: kq=%p kq->kq_count(%d) != count(%d), nmarker=%d",
func, line, kq, kq->kq_count, count, nmarker);
}
}
#define kq_check(a) kqueue_check(__func__, __LINE__, (a))
#else /* defined(DEBUG) */
#define kq_check(a) /* nothing */
#endif /* defined(DEBUG) */
/*
* 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(file_t *fp, size_t maxevents, struct kevent *ulistp,
const struct timespec *tsp, register_t *retval,
const struct kevent_ops *keops, struct kevent *kevbuf,
size_t kevcnt)
{
struct kqueue *kq;
struct kevent *kevp;
struct timespec ats, sleepts;
struct knote *kn, *marker, morker;
size_t count, nkev, nevents;
int timeout, error, rv;
filedesc_t *fdp;
fdp = curlwp->l_fd;
kq = fp->f_kqueue;
count = maxevents;
nkev = nevents = error = 0;
if (count == 0) {
*retval = 0;
return 0;
}
if (tsp) { /* timeout supplied */
ats = *tsp;
if (inittimeleft(&ats, &sleepts) == -1) {
*retval = maxevents;
return EINVAL;
}
timeout = tstohz(&ats);
if (timeout <= 0)
timeout = -1; /* do poll */
} else {
/* no timeout, wait forever */
timeout = 0;
}
memset(&morker, 0, sizeof(morker));
marker = &morker;
marker->kn_status = KN_MARKER;
mutex_spin_enter(&kq->kq_lock);
retry:
kevp = kevbuf;
if (kq->kq_count == 0) {
if (timeout >= 0) {
error = cv_timedwait_sig(&kq->kq_cv,
&kq->kq_lock, timeout);
if (error == 0) {
if (tsp == NULL || (timeout =
gettimeleft(&ats, &sleepts)) > 0)
goto retry;
} else {
/* don't restart after signals... */
if (error == ERESTART)
error = EINTR;
if (error == EWOULDBLOCK)
error = 0;
}
}
mutex_spin_exit(&kq->kq_lock);
} else {
/* mark end of knote list */
TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
/*
* Acquire the fdp->fd_lock interlock to avoid races with
* file creation/destruction from other threads.
*/
mutex_spin_exit(&kq->kq_lock);
mutex_enter(&fdp->fd_lock);
mutex_spin_enter(&kq->kq_lock);
while (count != 0) {
kn = TAILQ_FIRST(&kq->kq_head); /* get next knote */
while ((kn->kn_status & KN_MARKER) != 0) {
if (kn == marker) {
/* it's our marker, stop */
TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
if (count < maxevents || (tsp != NULL &&
(timeout = gettimeleft(&ats,
&sleepts)) <= 0))
goto done;
mutex_exit(&fdp->fd_lock);
goto retry;
}
/* someone else's marker. */
kn = TAILQ_NEXT(kn, kn_tqe);
}
kq_check(kq);
kq->kq_count--;
TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
kn->kn_status &= ~KN_QUEUED;
kn->kn_status |= KN_BUSY;
kq_check(kq);
if (kn->kn_status & KN_DISABLED) {
kn->kn_status &= ~KN_BUSY;
/* don't want disabled events */
continue;
}
if ((kn->kn_flags & EV_ONESHOT) == 0) {
mutex_spin_exit(&kq->kq_lock);
KASSERT(kn->kn_fop != NULL);
KASSERT(kn->kn_fop->f_event != NULL);
KERNEL_LOCK(1, NULL); /* XXXSMP */
KASSERT(mutex_owned(&fdp->fd_lock));
rv = (*kn->kn_fop->f_event)(kn, 0);
KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */
mutex_spin_enter(&kq->kq_lock);
/* Re-poll if note was re-enqueued. */
if ((kn->kn_status & KN_QUEUED) != 0) {
kn->kn_status &= ~KN_BUSY;
continue;
}
if (rv == 0) {
/*
* non-ONESHOT event that hasn't
* triggered again, so de-queue.
*/
kn->kn_status &= ~(KN_ACTIVE|KN_BUSY);
continue;
}
}
/* XXXAD should be got from f_event if !oneshot. */
*kevp++ = kn->kn_kevent;
nkev++;
if (kn->kn_flags & EV_ONESHOT) {
/* delete ONESHOT events after retrieval */
kn->kn_status &= ~KN_BUSY;
mutex_spin_exit(&kq->kq_lock);
knote_detach(kn, fdp, true);
mutex_enter(&fdp->fd_lock);
mutex_spin_enter(&kq->kq_lock);
} 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|KN_BUSY);
} else if (kn->kn_flags & EV_DISPATCH) {
kn->kn_status |= KN_DISABLED;
kn->kn_status &= ~(KN_QUEUED|KN_ACTIVE|KN_BUSY);
} else {
/* add event back on list */
kq_check(kq);
kn->kn_status |= KN_QUEUED;
kn->kn_status &= ~KN_BUSY;
TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
kq->kq_count++;
kq_check(kq);
}
if (nkev == kevcnt) {
/* do copyouts in kevcnt chunks */
mutex_spin_exit(&kq->kq_lock);
mutex_exit(&fdp->fd_lock);
error = (*keops->keo_put_events)
(keops->keo_private,
kevbuf, ulistp, nevents, nkev);
mutex_enter(&fdp->fd_lock);
mutex_spin_enter(&kq->kq_lock);
nevents += nkev;
nkev = 0;
kevp = kevbuf;
}
count--;
if (error != 0 || count == 0) {
/* remove marker */
TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
break;
}
}
done:
mutex_spin_exit(&kq->kq_lock);
mutex_exit(&fdp->fd_lock);
}
if (nkev != 0) {
/* copyout remaining events */
error = (*keops->keo_put_events)(keops->keo_private,
kevbuf, ulistp, nevents, nkev);
}
*retval = maxevents - count;
return error;
}
/*
* 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(file_t *fp, u_long com, void *data)
{
struct kfilter_mapping *km;
const struct kfilter *kfilter;
char *name;
int error;
km = data;
error = 0;
name = kmem_alloc(KFILTER_MAXNAME, KM_SLEEP);
switch (com) {
case KFILTER_BYFILTER: /* convert filter -> name */
rw_enter(&kqueue_filter_lock, RW_READER);
kfilter = kfilter_byfilter(km->filter);
if (kfilter != NULL) {
strlcpy(name, kfilter->name, KFILTER_MAXNAME);
rw_exit(&kqueue_filter_lock);
error = copyoutstr(name, km->name, km->len, NULL);
} else {
rw_exit(&kqueue_filter_lock);
error = ENOENT;
}
break;
case KFILTER_BYNAME: /* convert name -> filter */
error = copyinstr(km->name, name, KFILTER_MAXNAME, NULL);
if (error) {
break;
}
rw_enter(&kqueue_filter_lock, RW_READER);
kfilter = kfilter_byname(name);
if (kfilter != NULL)
km->filter = kfilter->filter;
else
error = ENOENT;
rw_exit(&kqueue_filter_lock);
break;
default:
error = ENOTTY;
break;
}
kmem_free(name, KFILTER_MAXNAME);
return (error);
}
/*
* fileops fcntl method for a kqueue descriptor.
*/
static int
kqueue_fcntl(file_t *fp, u_int com, void *data)
{
return (ENOTTY);
}
/*
* fileops poll method for a kqueue descriptor.
* Determine if kqueue has events pending.
*/
static int
kqueue_poll(file_t *fp, int events)
{
struct kqueue *kq;
int revents;
kq = fp->f_kqueue;
revents = 0;
if (events & (POLLIN | POLLRDNORM)) {
mutex_spin_enter(&kq->kq_lock);
if (kq->kq_count != 0) {
revents |= events & (POLLIN | POLLRDNORM);
} else {
selrecord(curlwp, &kq->kq_sel);
}
kq_check(kq);
mutex_spin_exit(&kq->kq_lock);
}
return revents;
}
/*
* fileops stat method for a kqueue descriptor.
* Returns dummy info, with st_size being number of events pending.
*/
static int
kqueue_stat(file_t *fp, struct stat *st)
{
struct kqueue *kq;
kq = fp->f_kqueue;
memset(st, 0, sizeof(*st));
st->st_size = kq->kq_count;
st->st_blksize = sizeof(struct kevent);
st->st_mode = S_IFIFO;
return 0;
}
static void
kqueue_doclose(struct kqueue *kq, struct klist *list, int fd)
{
struct knote *kn;
filedesc_t *fdp;
fdp = kq->kq_fdp;
KASSERT(mutex_owned(&fdp->fd_lock));
for (kn = SLIST_FIRST(list); kn != NULL;) {
if (kq != kn->kn_kq) {
kn = SLIST_NEXT(kn, kn_link);
continue;
}
knote_detach(kn, fdp, true);
mutex_enter(&fdp->fd_lock);
kn = SLIST_FIRST(list);
}
}
/*
* fileops close method for a kqueue descriptor.
*/
static int
kqueue_close(file_t *fp)
{
struct kqueue *kq;
filedesc_t *fdp;
fdfile_t *ff;
int i;
kq = fp->f_kqueue;
fp->f_kqueue = NULL;
fp->f_type = 0;
fdp = curlwp->l_fd;
mutex_enter(&fdp->fd_lock);
for (i = 0; i <= fdp->fd_lastkqfile; i++) {
if ((ff = fdp->fd_dt->dt_ff[i]) == NULL)
continue;
kqueue_doclose(kq, (struct klist *)&ff->ff_knlist, i);
}
if (fdp->fd_knhashmask != 0) {
for (i = 0; i < fdp->fd_knhashmask + 1; i++) {
kqueue_doclose(kq, &fdp->fd_knhash[i], -1);
}
}
mutex_exit(&fdp->fd_lock);
KASSERT(kq->kq_count == 0);
mutex_destroy(&kq->kq_lock);
cv_destroy(&kq->kq_cv);
seldestroy(&kq->kq_sel);
kmem_free(kq, sizeof(*kq));
return (0);
}
/*
* struct fileops kqfilter method for a kqueue descriptor.
* Event triggered when monitored kqueue changes.
*/
static int
kqueue_kqfilter(file_t *fp, struct knote *kn)
{
struct kqueue *kq;
kq = ((file_t *)kn->kn_obj)->f_kqueue;
KASSERT(fp == kn->kn_obj);
if (kn->kn_filter != EVFILT_READ)
return 1;
kn->kn_fop = &kqread_filtops;
mutex_enter(&kq->kq_lock);
SLIST_INSERT_HEAD(&kq->kq_sel.sel_klist, kn, kn_selnext);
mutex_exit(&kq->kq_lock);
return 0;
}
/*
* Walk down a list of knotes, activating them if their event has
* triggered. The caller's object lock (e.g. device driver lock)
* must be held.
*/
void
knote(struct klist *list, long hint)
{
struct knote *kn, *tmpkn;
SLIST_FOREACH_SAFE(kn, list, kn_selnext, tmpkn) {
KASSERT(kn->kn_fop != NULL);
KASSERT(kn->kn_fop->f_event != NULL);
if ((*kn->kn_fop->f_event)(kn, hint))
knote_activate(kn);
}
}
/*
* Remove all knotes referencing a specified fd
*/
void
knote_fdclose(int fd)
{
struct klist *list;
struct knote *kn;
filedesc_t *fdp;
fdp = curlwp->l_fd;
list = (struct klist *)&fdp->fd_dt->dt_ff[fd]->ff_knlist;
mutex_enter(&fdp->fd_lock);
while ((kn = SLIST_FIRST(list)) != NULL) {
knote_detach(kn, fdp, true);
mutex_enter(&fdp->fd_lock);
}
mutex_exit(&fdp->fd_lock);
}
/*
* Drop knote. Called with fdp->fd_lock held, and will drop before
* returning.
*/
static void
knote_detach(struct knote *kn, filedesc_t *fdp, bool dofop)
{
struct klist *list;
struct kqueue *kq;
kq = kn->kn_kq;
KASSERT((kn->kn_status & KN_MARKER) == 0);
KASSERT(mutex_owned(&fdp->fd_lock));
KASSERT(kn->kn_fop != NULL);
/* Remove from monitored object. */
if (dofop) {
KASSERT(kn->kn_fop->f_detach != NULL);
KERNEL_LOCK(1, NULL); /* XXXSMP */
(*kn->kn_fop->f_detach)(kn);
KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */
}
/* Remove from descriptor table. */
if (kn->kn_fop->f_isfd)
list = (struct klist *)&fdp->fd_dt->dt_ff[kn->kn_id]->ff_knlist;
else
list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
SLIST_REMOVE(list, kn, knote, kn_link);
/* Remove from kqueue. */
again:
mutex_spin_enter(&kq->kq_lock);
if ((kn->kn_status & KN_QUEUED) != 0) {
kq_check(kq);
kq->kq_count--;
TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
kn->kn_status &= ~KN_QUEUED;
kq_check(kq);
} else if (kn->kn_status & KN_BUSY) {
mutex_spin_exit(&kq->kq_lock);
goto again;
}
mutex_spin_exit(&kq->kq_lock);
mutex_exit(&fdp->fd_lock);
if (kn->kn_fop->f_isfd)
fd_putfile(kn->kn_id);
atomic_dec_uint(&kn->kn_kfilter->refcnt);
kmem_free(kn, sizeof(*kn));
}
/*
* Queue new event for knote.
*/
static void
knote_enqueue(struct knote *kn)
{
struct kqueue *kq;
KASSERT((kn->kn_status & KN_MARKER) == 0);
kq = kn->kn_kq;
mutex_spin_enter(&kq->kq_lock);
if ((kn->kn_status & KN_DISABLED) != 0) {
kn->kn_status &= ~KN_DISABLED;
}
if ((kn->kn_status & (KN_ACTIVE | KN_QUEUED)) == KN_ACTIVE) {
kq_check(kq);
kn->kn_status |= KN_QUEUED;
TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
kq->kq_count++;
kq_check(kq);
cv_broadcast(&kq->kq_cv);
selnotify(&kq->kq_sel, 0, NOTE_SUBMIT);
}
mutex_spin_exit(&kq->kq_lock);
}
/*
* Queue new event for knote.
*/
static void
knote_activate(struct knote *kn)
{
struct kqueue *kq;
KASSERT((kn->kn_status & KN_MARKER) == 0);
kq = kn->kn_kq;
mutex_spin_enter(&kq->kq_lock);
kn->kn_status |= KN_ACTIVE;
if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) {
kq_check(kq);
kn->kn_status |= KN_QUEUED;
TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
kq->kq_count++;
kq_check(kq);
cv_broadcast(&kq->kq_cv);
selnotify(&kq->kq_sel, 0, NOTE_SUBMIT);
}
mutex_spin_exit(&kq->kq_lock);
}
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