/*- * Copyright (c) 1999,2000,2001 Jonathan Lemon * 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 1.2.2.10 2004/04/04 07:03:14 cperciva Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Global token for kqueue subsystem */ #if 0 struct lwkt_token kq_token = LWKT_TOKEN_INITIALIZER(kq_token); SYSCTL_LONG(_lwkt, OID_AUTO, kq_collisions, CTLFLAG_RW, &kq_token.t_collisions, 0, "Collision counter of kq_token"); #endif MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); struct kevent_copyin_args { struct kevent_args *ka; int pchanges; }; static int kqueue_sleep(struct kqueue *kq, struct timespec *tsp); static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, struct knote *marker); static int kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags); static int kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags); static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data, struct ucred *cred, struct sysmsg *msg); static int kqueue_kqfilter(struct file *fp, struct knote *kn); static int kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred); static int kqueue_close(struct file *fp); static void kqueue_wakeup(struct kqueue *kq); static int filter_attach(struct knote *kn); static int filter_event(struct knote *kn, long hint); /* * MPSAFE */ static struct fileops kqueueops = { .fo_read = kqueue_read, .fo_write = kqueue_write, .fo_ioctl = kqueue_ioctl, .fo_kqfilter = kqueue_kqfilter, .fo_stat = kqueue_stat, .fo_close = kqueue_close, .fo_shutdown = nofo_shutdown }; static void knote_attach(struct knote *kn); static void knote_drop(struct knote *kn); static void knote_detach_and_drop(struct knote *kn); static void knote_enqueue(struct knote *kn); static void knote_dequeue(struct knote *kn); 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 = { FILTEROP_ISFD, filt_fileattach, NULL, NULL }; static struct filterops kqread_filtops = { FILTEROP_ISFD, 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 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"); static int kq_checkloop = 1000000; SYSCTL_INT(_kern, OID_AUTO, kq_checkloop, CTLFLAG_RW, &kq_checkloop, 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)) extern struct filterops aio_filtops; extern struct filterops sig_filtops; /* * Table for for all system-defined filters. */ static struct filterops *sysfilt_ops[] = { &file_filtops, /* EVFILT_READ */ &file_filtops, /* EVFILT_WRITE */ &aio_filtops, /* EVFILT_AIO */ &file_filtops, /* EVFILT_VNODE */ &proc_filtops, /* EVFILT_PROC */ &sig_filtops, /* EVFILT_SIGNAL */ &timer_filtops, /* EVFILT_TIMER */ &file_filtops, /* EVFILT_EXCEPT */ }; static int filt_fileattach(struct knote *kn) { return (fo_kqfilter(kn->kn_fp, kn)); } /* * MPSAFE */ static int kqueue_kqfilter(struct file *fp, struct knote *kn) { struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; if (kn->kn_filter != EVFILT_READ) return (EOPNOTSUPP); kn->kn_fop = &kqread_filtops; knote_insert(&kq->kq_kqinfo.ki_note, kn); return (0); } static void filt_kqdetach(struct knote *kn) { struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; knote_remove(&kq->kq_kqinfo.ki_note, kn); } /*ARGSUSED*/ static int filt_kqueue(struct knote *kn, long hint) { struct kqueue *kq = (struct kqueue *)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; 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 (!PRISON_CHECK(curthread->td_ucred, p->p_ucred)) { if (p) PRELE(p); return (EACCES); } lwkt_gettoken(&p->p_token); 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; } knote_insert(&p->p_klist, kn); /* * 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 negistered. */ if (immediate && filt_proc(kn, NOTE_EXIT)) KNOTE_ACTIVATE(kn); lwkt_reltoken(&p->p_token); PRELE(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; if (kn->kn_status & KN_DETACHED) return; /* XXX locking? take proc_token here? */ p = kn->kn_ptr.p_proc; knote_remove(&p->p_klist, kn); } 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. Detach the * knote from the process now because the process will be poof, * gone later on. */ if (event == NOTE_EXIT) { struct proc *p = kn->kn_ptr.p_proc; if ((kn->kn_status & KN_DETACHED) == 0) { PHOLD(p); knote_remove(&p->p_klist, kn); kn->kn_status |= KN_DETACHED; kn->kn_data = p->p_xstat; kn->kn_ptr.p_proc = NULL; PRELE(p); } kn->kn_flags |= (EV_EOF | EV_NODATA | 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); if (error) kn->kn_fflags |= NOTE_TRACKERR; } return (kn->kn_fflags != 0); } /* * The callout interlocks with callout_terminate() but can still * race a deletion so if KN_DELETING is set we just don't touch * the knote. */ static void filt_timerexpire(void *knx) { struct lwkt_token *tok; struct knote *kn = knx; struct callout *calloutp; struct timeval tv; int tticks; tok = lwkt_token_pool_lookup(kn->kn_kq); lwkt_gettoken(tok); if ((kn->kn_status & KN_DELETING) == 0) { 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_high(&tv); calloutp = (struct callout *)kn->kn_hook; callout_reset(calloutp, tticks, filt_timerexpire, kn); } } lwkt_reltoken(tok); } /* * 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) { kn->kn_hook = NULL; return (ENOMEM); } kq_ncallouts++; tv.tv_sec = kn->kn_sdata / 1000; tv.tv_usec = (kn->kn_sdata % 1000) * 1000; tticks = tvtohz_high(&tv); kn->kn_flags |= EV_CLEAR; /* automatically set */ calloutp = kmalloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); callout_init(calloutp); kn->kn_hook = (caddr_t)calloutp; callout_reset(calloutp, tticks, filt_timerexpire, kn); return (0); } /* * This function is called with the knote flagged locked but it is * still possible to race a callout event due to the callback blocking. * We must call callout_terminate() instead of callout_stop() to deal * with the race. */ static void filt_timerdetach(struct knote *kn) { struct callout *calloutp; calloutp = (struct callout *)kn->kn_hook; callout_terminate(calloutp); kfree(calloutp, M_KQUEUE); kq_ncallouts--; } static int filt_timer(struct knote *kn, long hint) { return (kn->kn_data != 0); } /* * Acquire a knote, return non-zero on success, 0 on failure. * * If we cannot acquire the knote we sleep and return 0. The knote * may be stale on return in this case and the caller must restart * whatever loop they are in. * * Related kq token must be held. */ static __inline int knote_acquire(struct knote *kn) { if (kn->kn_status & KN_PROCESSING) { kn->kn_status |= KN_WAITING | KN_REPROCESS; tsleep(kn, 0, "kqepts", hz); /* knote may be stale now */ return(0); } kn->kn_status |= KN_PROCESSING; return(1); } /* * Release an acquired knote, clearing KN_PROCESSING and handling any * KN_REPROCESS events. * * Caller must be holding the related kq token * * Non-zero is returned if the knote is destroyed or detached. */ static __inline int knote_release(struct knote *kn) { while (kn->kn_status & KN_REPROCESS) { kn->kn_status &= ~KN_REPROCESS; if (kn->kn_status & KN_WAITING) { kn->kn_status &= ~KN_WAITING; wakeup(kn); } if (kn->kn_status & KN_DELETING) { knote_detach_and_drop(kn); return(1); /* NOT REACHED */ } if (filter_event(kn, 0)) KNOTE_ACTIVATE(kn); } if (kn->kn_status & KN_DETACHED) { kn->kn_status &= ~KN_PROCESSING; return(1); } else { kn->kn_status &= ~KN_PROCESSING; return(0); } } /* * Initialize a kqueue. * * NOTE: The lwp/proc code initializes a kqueue for select/poll ops. * * MPSAFE */ void kqueue_init(struct kqueue *kq, struct filedesc *fdp) { TAILQ_INIT(&kq->kq_knpend); TAILQ_INIT(&kq->kq_knlist); kq->kq_count = 0; kq->kq_fdp = fdp; SLIST_INIT(&kq->kq_kqinfo.ki_note); } /* * Terminate a kqueue. Freeing the actual kq itself is left up to the * caller (it might be embedded in a lwp so we don't do it here). * * The kq's knlist must be completely eradicated so block on any * processing races. */ void kqueue_terminate(struct kqueue *kq) { struct lwkt_token *tok; struct knote *kn; tok = lwkt_token_pool_lookup(kq); lwkt_gettoken(tok); while ((kn = TAILQ_FIRST(&kq->kq_knlist)) != NULL) { if (knote_acquire(kn)) knote_detach_and_drop(kn); } if (kq->kq_knhash) { hashdestroy(kq->kq_knhash, M_KQUEUE, kq->kq_knhashmask); kq->kq_knhash = NULL; kq->kq_knhashmask = 0; } lwkt_reltoken(tok); } /* * MPSAFE */ int sys_kqueue(struct kqueue_args *uap) { struct thread *td = curthread; struct kqueue *kq; struct file *fp; int fd, error; error = falloc(td->td_lwp, &fp, &fd); if (error) return (error); fp->f_flag = FREAD | FWRITE; fp->f_type = DTYPE_KQUEUE; fp->f_ops = &kqueueops; kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO); kqueue_init(kq, td->td_proc->p_fd); fp->f_data = kq; fsetfd(kq->kq_fdp, fp, fd); uap->sysmsg_result = fd; fdrop(fp); return (error); } /* * Copy 'count' items into the destination list pointed to by uap->eventlist. */ static int kevent_copyout(void *arg, struct kevent *kevp, int count, int *res) { struct kevent_copyin_args *kap; int error; kap = (struct kevent_copyin_args *)arg; error = copyout(kevp, kap->ka->eventlist, count * sizeof(*kevp)); if (error == 0) { kap->ka->eventlist += count; *res += count; } else { *res = -1; } return (error); } /* * Copy at most 'max' items from the list pointed to by kap->changelist, * return number of items in 'events'. */ static int kevent_copyin(void *arg, struct kevent *kevp, int max, int *events) { struct kevent_copyin_args *kap; int error, count; kap = (struct kevent_copyin_args *)arg; count = min(kap->ka->nchanges - kap->pchanges, max); error = copyin(kap->ka->changelist, kevp, count * sizeof *kevp); if (error == 0) { kap->ka->changelist += count; kap->pchanges += count; *events = count; } return (error); } /* * MPSAFE */ int kern_kevent(struct kqueue *kq, int nevents, int *res, void *uap, k_copyin_fn kevent_copyinfn, k_copyout_fn kevent_copyoutfn, struct timespec *tsp_in) { struct kevent *kevp; struct timespec *tsp; int i, n, total, error, nerrors = 0; int lres; int limit = kq_checkloop; struct kevent kev[KQ_NEVENTS]; struct knote marker; struct lwkt_token *tok; if (tsp_in == NULL || tsp_in->tv_sec || tsp_in->tv_nsec) atomic_set_int(&curthread->td_mpflags, TDF_MP_BATCH_DEMARC); tsp = tsp_in; *res = 0; tok = lwkt_token_pool_lookup(kq); lwkt_gettoken(tok); for ( ;; ) { n = 0; error = kevent_copyinfn(uap, kev, KQ_NEVENTS, &n); if (error) goto done; if (n == 0) break; for (i = 0; i < n; i++) { kevp = &kev[i]; kevp->flags &= ~EV_SYSFLAGS; error = kqueue_register(kq, kevp); /* * If a registration returns an error we * immediately post the error. The kevent() * call itself will fail with the error if * no space is available for posting. * * Such errors normally bypass the timeout/blocking * code. However, if the copyoutfn function refuses * to post the error (see sys_poll()), then we * ignore it too. */ if (error) { kevp->flags = EV_ERROR; kevp->data = error; lres = *res; kevent_copyoutfn(uap, kevp, 1, res); if (*res < 0) { goto done; } else if (lres != *res) { nevents--; nerrors++; } } } } if (nerrors) { error = 0; goto done; } /* * Acquire/wait for events - setup timeout */ if (tsp != NULL) { struct timespec ats; if (tsp->tv_sec || tsp->tv_nsec) { getnanouptime(&ats); timespecadd(tsp, &ats); /* tsp = target time */ } } /* * Loop as required. * * Collect as many events as we can. Sleeping on successive * loops is disabled if copyoutfn has incremented (*res). * * The loop stops if an error occurs, all events have been * scanned (the marker has been reached), or fewer than the * maximum number of events is found. * * The copyoutfn function does not have to increment (*res) in * order for the loop to continue. * * NOTE: doselect() usually passes 0x7FFFFFFF for nevents. */ total = 0; error = 0; marker.kn_filter = EVFILT_MARKER; marker.kn_status = KN_PROCESSING; TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); while ((n = nevents - total) > 0) { if (n > KQ_NEVENTS) n = KQ_NEVENTS; /* * If no events are pending sleep until timeout (if any) * or an event occurs. * * After the sleep completes the marker is moved to the * end of the list, making any received events available * to our scan. */ if (kq->kq_count == 0 && *res == 0) { error = kqueue_sleep(kq, tsp); if (error) break; TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); } /* * Process all received events * Account for all non-spurious events in our total */ i = kqueue_scan(kq, kev, n, &marker); if (i) { lres = *res; error = kevent_copyoutfn(uap, kev, i, res); total += *res - lres; if (error) break; } if (limit && --limit == 0) panic("kqueue: checkloop failed i=%d", i); /* * Normally when fewer events are returned than requested * we can stop. However, if only spurious events were * collected the copyout will not bump (*res) and we have * to continue. */ if (i < n && *res) break; /* * Deal with an edge case where spurious events can cause * a loop to occur without moving the marker. This can * prevent kqueue_scan() from picking up new events which * race us. We must be sure to move the marker for this * case. * * NOTE: We do not want to move the marker if events * were scanned because normal kqueue operations * may reactivate events. Moving the marker in * that case could result in duplicates for the * same event. */ if (i == 0) { TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); } } TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); /* Timeouts do not return EWOULDBLOCK. */ if (error == EWOULDBLOCK) error = 0; done: lwkt_reltoken(tok); return (error); } /* * MPALMOSTSAFE */ int sys_kevent(struct kevent_args *uap) { struct thread *td = curthread; struct proc *p = td->td_proc; struct timespec ts, *tsp; struct kqueue *kq; struct file *fp = NULL; struct kevent_copyin_args *kap, ka; int error; if (uap->timeout) { error = copyin(uap->timeout, &ts, sizeof(ts)); if (error) return (error); tsp = &ts; } else { tsp = NULL; } fp = holdfp(p->p_fd, uap->fd, -1); if (fp == NULL) return (EBADF); if (fp->f_type != DTYPE_KQUEUE) { fdrop(fp); return (EBADF); } kq = (struct kqueue *)fp->f_data; kap = &ka; kap->ka = uap; kap->pchanges = 0; error = kern_kevent(kq, uap->nevents, &uap->sysmsg_result, kap, kevent_copyin, kevent_copyout, tsp); fdrop(fp); return (error); } /* * Caller must be holding the kq token */ int kqueue_register(struct kqueue *kq, struct kevent *kev) { struct lwkt_token *tok; struct filedesc *fdp = kq->kq_fdp; struct filterops *fops; struct file *fp = NULL; struct knote *kn = NULL; int 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. */ kprintf("unknown filter: %d\n", kev->filter); return (EINVAL); } tok = lwkt_token_pool_lookup(kq); lwkt_gettoken(tok); if (fops->f_flags & FILTEROP_ISFD) { /* validate descriptor */ fp = holdfp(fdp, kev->ident, -1); if (fp == NULL) { lwkt_reltoken(tok); return (EBADF); } lwkt_getpooltoken(&fp->f_klist); again1: SLIST_FOREACH(kn, &fp->f_klist, kn_link) { if (kn->kn_kq == kq && kn->kn_filter == kev->filter && kn->kn_id == kev->ident) { if (knote_acquire(kn) == 0) goto again1; break; } } lwkt_relpooltoken(&fp->f_klist); } else { if (kq->kq_knhashmask) { struct klist *list; list = &kq->kq_knhash[ KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; lwkt_getpooltoken(list); again2: SLIST_FOREACH(kn, list, kn_link) { if (kn->kn_id == kev->ident && kn->kn_filter == kev->filter) { if (knote_acquire(kn) == 0) goto again2; break; } } lwkt_relpooltoken(list); } } /* * NOTE: At this point if kn is non-NULL we will have acquired * it and set KN_PROCESSING. */ 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; /* * KN_PROCESSING prevents the knote from getting * ripped out from under us while we are trying * to attach it, in case the attach blocks. */ kn->kn_status = KN_PROCESSING; knote_attach(kn); if ((error = filter_attach(kn)) != 0) { kn->kn_status |= KN_DELETING | KN_REPROCESS; knote_drop(kn); goto done; } /* * Interlock against close races which either tried * to remove our knote while we were blocked or missed * it entirely prior to our attachment. We do not * want to end up with a knote on a closed descriptor. */ if ((fops->f_flags & FILTEROP_ISFD) && checkfdclosed(fdp, kev->ident, kn->kn_fp)) { kn->kn_status |= KN_DELETING | KN_REPROCESS; } } 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. */ KKASSERT(kn->kn_status & KN_PROCESSING); kn->kn_sfflags = kev->fflags; kn->kn_sdata = kev->data; kn->kn_kevent.udata = kev->udata; } /* * Execute the filter event to immediately activate the * knote if necessary. If reprocessing events are pending * due to blocking above we do not run the filter here * but instead let knote_release() do it. Otherwise we * might run the filter on a deleted event. */ if ((kn->kn_status & KN_REPROCESS) == 0) { if (filter_event(kn, 0)) KNOTE_ACTIVATE(kn); } } else if (kev->flags & EV_DELETE) { /* * Delete the existing knote */ knote_detach_and_drop(kn); goto done; } /* * Disablement does not deactivate a knote here. */ if ((kev->flags & EV_DISABLE) && ((kn->kn_status & KN_DISABLED) == 0)) { kn->kn_status |= KN_DISABLED; } /* * Re-enablement may have to immediately enqueue an active knote. */ if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { kn->kn_status &= ~KN_DISABLED; if ((kn->kn_status & KN_ACTIVE) && ((kn->kn_status & KN_QUEUED) == 0)) { knote_enqueue(kn); } } /* * Handle any required reprocessing */ knote_release(kn); /* kn may be invalid now */ done: lwkt_reltoken(tok); if (fp != NULL) fdrop(fp); return (error); } /* * Block as necessary until the target time is reached. * If tsp is NULL we block indefinitely. If tsp->ts_secs/nsecs are both * 0 we do not block at all. * * Caller must be holding the kq token. */ static int kqueue_sleep(struct kqueue *kq, struct timespec *tsp) { int error = 0; if (tsp == NULL) { kq->kq_state |= KQ_SLEEP; error = tsleep(kq, PCATCH, "kqread", 0); } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) { error = EWOULDBLOCK; } else { struct timespec ats; struct timespec atx = *tsp; int timeout; getnanouptime(&ats); timespecsub(&atx, &ats); if (ats.tv_sec < 0) { error = EWOULDBLOCK; } else { timeout = atx.tv_sec > 24 * 60 * 60 ? 24 * 60 * 60 * hz : tstohz_high(&atx); kq->kq_state |= KQ_SLEEP; error = tsleep(kq, PCATCH, "kqread", timeout); } } /* don't restart after signals... */ if (error == ERESTART) return (EINTR); return (error); } /* * Scan the kqueue, return the number of active events placed in kevp up * to count. * * Continuous mode events may get recycled, do not continue scanning past * marker unless no events have been collected. * * Caller must be holding the kq token */ static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, struct knote *marker) { struct knote *kn, local_marker; int total; total = 0; local_marker.kn_filter = EVFILT_MARKER; local_marker.kn_status = KN_PROCESSING; /* * Collect events. */ TAILQ_INSERT_HEAD(&kq->kq_knpend, &local_marker, kn_tqe); while (count) { kn = TAILQ_NEXT(&local_marker, kn_tqe); if (kn->kn_filter == EVFILT_MARKER) { /* Marker reached, we are done */ if (kn == marker) break; /* Move local marker past some other threads marker */ kn = TAILQ_NEXT(kn, kn_tqe); TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); TAILQ_INSERT_BEFORE(kn, &local_marker, kn_tqe); continue; } /* * We can't skip a knote undergoing processing, otherwise * we risk not returning it when the user process expects * it should be returned. Sleep and retry. */ if (knote_acquire(kn) == 0) continue; /* * Remove the event for processing. * * WARNING! We must leave KN_QUEUED set to prevent the * event from being KNOTE_ACTIVATE()d while * the queue state is in limbo, in case we * block. * * WARNING! We must set KN_PROCESSING to avoid races * against deletion or another thread's * processing. */ TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); kq->kq_count--; /* * We have to deal with an extremely important race against * file descriptor close()s here. The file descriptor can * disappear MPSAFE, and there is a small window of * opportunity between that and the call to knote_fdclose(). * * If we hit that window here while doselect or dopoll is * trying to delete a spurious event they will not be able * to match up the event against a knote and will go haywire. */ if ((kn->kn_fop->f_flags & FILTEROP_ISFD) && checkfdclosed(kq->kq_fdp, kn->kn_kevent.ident, kn->kn_fp)) { kn->kn_status |= KN_DELETING | KN_REPROCESS; } if (kn->kn_status & KN_DISABLED) { /* * If disabled we ensure the event is not queued * but leave its active bit set. On re-enablement * the event may be immediately triggered. */ kn->kn_status &= ~KN_QUEUED; } else if ((kn->kn_flags & EV_ONESHOT) == 0 && (kn->kn_status & KN_DELETING) == 0 && filter_event(kn, 0) == 0) { /* * If not running in one-shot mode and the event * is no longer present we ensure it is removed * from the queue and ignore it. */ kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); } else { /* * Post the event */ *kevp++ = kn->kn_kevent; ++total; --count; if (kn->kn_flags & EV_ONESHOT) { kn->kn_status &= ~KN_QUEUED; kn->kn_status |= KN_DELETING | KN_REPROCESS; } else if (kn->kn_flags & EV_CLEAR) { kn->kn_data = 0; kn->kn_fflags = 0; kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); } else { TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); kq->kq_count++; } } /* * Handle any post-processing states */ knote_release(kn); } TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); return (total); } /* * XXX * This could be expanded to call kqueue_scan, if desired. * * MPSAFE */ static int kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags) { return (ENXIO); } /* * MPSAFE */ static int kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags) { return (ENXIO); } /* * MPALMOSTSAFE */ static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data, struct ucred *cred, struct sysmsg *msg) { struct lwkt_token *tok; struct kqueue *kq; int error; kq = (struct kqueue *)fp->f_data; tok = lwkt_token_pool_lookup(kq); lwkt_gettoken(tok); switch(com) { case FIOASYNC: if (*(int *)data) kq->kq_state |= KQ_ASYNC; else kq->kq_state &= ~KQ_ASYNC; error = 0; break; case FIOSETOWN: error = fsetown(*(int *)data, &kq->kq_sigio); break; default: error = ENOTTY; break; } lwkt_reltoken(tok); return (error); } /* * MPSAFE */ static int kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred) { struct kqueue *kq = (struct kqueue *)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); } /* * MPSAFE */ static int kqueue_close(struct file *fp) { struct kqueue *kq = (struct kqueue *)fp->f_data; kqueue_terminate(kq); fp->f_data = NULL; funsetown(&kq->kq_sigio); kfree(kq, M_KQUEUE); return (0); } static void kqueue_wakeup(struct kqueue *kq) { if (kq->kq_state & KQ_SLEEP) { kq->kq_state &= ~KQ_SLEEP; wakeup(kq); } KNOTE(&kq->kq_kqinfo.ki_note, 0); } /* * Calls filterops f_attach function, acquiring mplock if filter is not * marked as FILTEROP_MPSAFE. * * Caller must be holding the related kq token */ static int filter_attach(struct knote *kn) { int ret; if (!(kn->kn_fop->f_flags & FILTEROP_MPSAFE)) { get_mplock(); ret = kn->kn_fop->f_attach(kn); rel_mplock(); } else { ret = kn->kn_fop->f_attach(kn); } return (ret); } /* * Detach the knote and drop it, destroying the knote. * * Calls filterops f_detach function, acquiring mplock if filter is not * marked as FILTEROP_MPSAFE. * * Caller must be holding the related kq token */ static void knote_detach_and_drop(struct knote *kn) { kn->kn_status |= KN_DELETING | KN_REPROCESS; if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { kn->kn_fop->f_detach(kn); } else { get_mplock(); kn->kn_fop->f_detach(kn); rel_mplock(); } knote_drop(kn); } /* * Calls filterops f_event function, acquiring mplock if filter is not * marked as FILTEROP_MPSAFE. * * If the knote is in the middle of being created or deleted we cannot * safely call the filter op. * * Caller must be holding the related kq token */ static int filter_event(struct knote *kn, long hint) { int ret; if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { ret = kn->kn_fop->f_event(kn, hint); } else { get_mplock(); ret = kn->kn_fop->f_event(kn, hint); rel_mplock(); } return (ret); } /* * Walk down a list of knotes, activating them if their event has triggered. * * If we encounter any knotes which are undergoing processing we just mark * them for reprocessing and do not try to [re]activate the knote. However, * if a hint is being passed we have to wait and that makes things a bit * sticky. */ void knote(struct klist *list, long hint) { struct kqueue *kq; struct knote *kn; struct knote *kntmp; lwkt_getpooltoken(list); restart: SLIST_FOREACH(kn, list, kn_next) { kq = kn->kn_kq; lwkt_getpooltoken(kq); /* temporary verification hack */ SLIST_FOREACH(kntmp, list, kn_next) { if (kn == kntmp) break; } if (kn != kntmp || kn->kn_kq != kq) { lwkt_relpooltoken(kq); goto restart; } if (kn->kn_status & KN_PROCESSING) { /* * Someone else is processing the knote, ask the * other thread to reprocess it and don't mess * with it otherwise. */ if (hint == 0) { kn->kn_status |= KN_REPROCESS; lwkt_relpooltoken(kq); continue; } /* * If the hint is non-zero we have to wait or risk * losing the state the caller is trying to update. * * XXX This is a real problem, certain process * and signal filters will bump kn_data for * already-processed notes more than once if * we restart the list scan. FIXME. */ kn->kn_status |= KN_WAITING | KN_REPROCESS; tsleep(kn, 0, "knotec", hz); lwkt_relpooltoken(kq); goto restart; } /* * Become the reprocessing master ourselves. * * If hint is non-zer running the event is mandatory * when not deleting so do it whether reprocessing is * set or not. */ kn->kn_status |= KN_PROCESSING; if ((kn->kn_status & KN_DELETING) == 0) { if (filter_event(kn, hint)) KNOTE_ACTIVATE(kn); } if (knote_release(kn)) { lwkt_relpooltoken(kq); goto restart; } lwkt_relpooltoken(kq); } lwkt_relpooltoken(list); } /* * Insert knote at head of klist. * * This function may only be called via a filter function and thus * kq_token should already be held and marked for processing. */ void knote_insert(struct klist *klist, struct knote *kn) { lwkt_getpooltoken(klist); KKASSERT(kn->kn_status & KN_PROCESSING); SLIST_INSERT_HEAD(klist, kn, kn_next); lwkt_relpooltoken(klist); } /* * Remove knote from a klist * * This function may only be called via a filter function and thus * kq_token should already be held and marked for processing. */ void knote_remove(struct klist *klist, struct knote *kn) { lwkt_getpooltoken(klist); KKASSERT(kn->kn_status & KN_PROCESSING); SLIST_REMOVE(klist, kn, knote, kn_next); lwkt_relpooltoken(klist); } #if 0 /* * Remove all knotes from a specified klist * * Only called from aio. */ void knote_empty(struct klist *list) { struct knote *kn; lwkt_gettoken(&kq_token); while ((kn = SLIST_FIRST(list)) != NULL) { if (knote_acquire(kn)) knote_detach_and_drop(kn); } lwkt_reltoken(&kq_token); } #endif void knote_assume_knotes(struct kqinfo *src, struct kqinfo *dst, struct filterops *ops, void *hook) { struct kqueue *kq; struct knote *kn; lwkt_getpooltoken(&src->ki_note); lwkt_getpooltoken(&dst->ki_note); while ((kn = SLIST_FIRST(&src->ki_note)) != NULL) { kq = kn->kn_kq; lwkt_getpooltoken(kq); if (SLIST_FIRST(&src->ki_note) != kn || kn->kn_kq != kq) { lwkt_relpooltoken(kq); continue; } if (knote_acquire(kn)) { knote_remove(&src->ki_note, kn); kn->kn_fop = ops; kn->kn_hook = hook; knote_insert(&dst->ki_note, kn); knote_release(kn); /* kn may be invalid now */ } lwkt_relpooltoken(kq); } lwkt_relpooltoken(&dst->ki_note); lwkt_relpooltoken(&src->ki_note); } /* * Remove all knotes referencing a specified fd */ void knote_fdclose(struct file *fp, struct filedesc *fdp, int fd) { struct kqueue *kq; struct knote *kn; struct knote *kntmp; lwkt_getpooltoken(&fp->f_klist); restart: SLIST_FOREACH(kn, &fp->f_klist, kn_link) { if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) { kq = kn->kn_kq; lwkt_getpooltoken(kq); /* temporary verification hack */ SLIST_FOREACH(kntmp, &fp->f_klist, kn_link) { if (kn == kntmp) break; } if (kn != kntmp || kn->kn_kq->kq_fdp != fdp || kn->kn_id != fd || kn->kn_kq != kq) { lwkt_relpooltoken(kq); goto restart; } if (knote_acquire(kn)) knote_detach_and_drop(kn); lwkt_relpooltoken(kq); goto restart; } } lwkt_relpooltoken(&fp->f_klist); } /* * Low level attach function. * * The knote should already be marked for processing. * Caller must hold the related kq token. */ static void knote_attach(struct knote *kn) { struct klist *list; struct kqueue *kq = kn->kn_kq; if (kn->kn_fop->f_flags & FILTEROP_ISFD) { KKASSERT(kn->kn_fp); list = &kn->kn_fp->f_klist; } else { if (kq->kq_knhashmask == 0) kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, &kq->kq_knhashmask); list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; } lwkt_getpooltoken(list); SLIST_INSERT_HEAD(list, kn, kn_link); TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink); lwkt_relpooltoken(list); } /* * Low level drop function. * * The knote should already be marked for processing. * Caller must hold the related kq token. */ static void knote_drop(struct knote *kn) { struct kqueue *kq; struct klist *list; kq = kn->kn_kq; if (kn->kn_fop->f_flags & FILTEROP_ISFD) list = &kn->kn_fp->f_klist; else list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; lwkt_getpooltoken(list); SLIST_REMOVE(list, kn, knote, kn_link); TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink); if (kn->kn_status & KN_QUEUED) knote_dequeue(kn); if (kn->kn_fop->f_flags & FILTEROP_ISFD) { fdrop(kn->kn_fp); kn->kn_fp = NULL; } knote_free(kn); lwkt_relpooltoken(list); } /* * Low level enqueue function. * * The knote should already be marked for processing. * Caller must be holding the kq token */ static void knote_enqueue(struct knote *kn) { struct kqueue *kq = kn->kn_kq; KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); kn->kn_status |= KN_QUEUED; ++kq->kq_count; /* * Send SIGIO on request (typically set up as a mailbox signal) */ if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1) pgsigio(kq->kq_sigio, SIGIO, 0); kqueue_wakeup(kq); } /* * Low level dequeue function. * * The knote should already be marked for processing. * Caller must be holding the kq token */ static void knote_dequeue(struct knote *kn) { struct kqueue *kq = kn->kn_kq; KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); kn->kn_status &= ~KN_QUEUED; kq->kq_count--; } static struct knote * knote_alloc(void) { return kmalloc(sizeof(struct knote), M_KQUEUE, M_WAITOK); } static void knote_free(struct knote *kn) { kfree(kn, M_KQUEUE); }