/*- * Copyright (c) 1999,2000,2001 Jonathan Lemon * Copyright 2004 John-Mark Gurney * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #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 #include #include #include #include static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); /* * This lock is used if multiple kq locks are required. This possibly * should be made into a per proc lock. */ static struct mtx kq_global; MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); #define KQ_GLOBAL_LOCK(lck, haslck) do { \ if (!haslck) \ mtx_lock(lck); \ haslck = 1; \ } while (0) #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ if (haslck) \ mtx_unlock(lck); \ haslck = 0; \ } while (0) TASKQUEUE_DEFINE_THREAD(kqueue); static int kevent_copyout(struct kevent **eventlist, enum uio_seg eventseg, struct kevent *kevp, int count); static int kqueue_aquire(struct file *fp, struct kqueue **kqp); static void kqueue_release(struct kqueue *kq, int locked); static int kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, int waitok); static void kqueue_task(void *arg, int pending); static int kqueue_scan(struct kqueue *kq, int maxevents, struct kevent *eventlist, enum uio_seg eventseg, const struct timespec *timeout, struct kevent *keva, struct thread *td); static void kqueue_wakeup(struct kqueue *kq); static struct filterops *kqueue_fo_find(int filt); static void kqueue_fo_release(int filt); static fo_rdwr_t kqueue_read; static fo_rdwr_t kqueue_write; static fo_ioctl_t kqueue_ioctl; static fo_poll_t kqueue_poll; static fo_kqfilter_t kqueue_kqfilter; static fo_stat_t kqueue_stat; static fo_close_t kqueue_close; static struct fileops kqueueops = { .fo_read = kqueue_read, .fo_write = kqueue_write, .fo_ioctl = kqueue_ioctl, .fo_poll = kqueue_poll, .fo_kqfilter = kqueue_kqfilter, .fo_stat = kqueue_stat, .fo_close = kqueue_close, }; static int knote_attach(struct knote *kn, struct kqueue *kq); static void knote_drop(struct knote *kn, struct thread *td); static void knote_enqueue(struct knote *kn); static void knote_dequeue(struct knote *kn); static void knote_init(void); static struct knote *knote_alloc(int waitok); static void knote_free(struct knote *kn); static void filt_kqdetach(struct knote *kn); static int filt_kqueue(struct knote *kn, long hint); static int filt_procattach(struct knote *kn); static void filt_procdetach(struct knote *kn); static int filt_proc(struct knote *kn, long hint); static int filt_fileattach(struct knote *kn); static void filt_timerexpire(void *knx); static int filt_timerattach(struct knote *kn); static void filt_timerdetach(struct knote *kn); static int filt_timer(struct knote *kn, long hint); static struct filterops file_filtops = { 1, filt_fileattach, NULL, NULL }; static struct filterops kqread_filtops = { 1, NULL, filt_kqdetach, filt_kqueue }; /* XXX - move to kern_proc.c? */ static struct filterops proc_filtops = { 0, filt_procattach, filt_procdetach, filt_proc }; static struct filterops timer_filtops = { 0, filt_timerattach, filt_timerdetach, filt_timer }; static uma_zone_t knote_zone; static int kq_ncallouts = 0; static int kq_calloutmax = (4 * 1024); SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); /* XXX - ensure not KN_INFLUX?? */ #define KNOTE_ACTIVATE(kn, islock) do { \ if ((islock)) \ mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ else \ KQ_LOCK((kn)->kn_kq); \ (kn)->kn_status |= KN_ACTIVE; \ if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ knote_enqueue((kn)); \ if (!(islock)) \ KQ_UNLOCK((kn)->kn_kq); \ } while(0) #define KQ_LOCK(kq) do { \ mtx_lock(&(kq)->kq_lock); \ } while (0) #define KQ_FLUX_WAKEUP(kq) do { \ if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ (kq)->kq_state &= ~KQ_FLUXWAIT; \ wakeup((kq)); \ } \ } while (0) #define KQ_UNLOCK_FLUX(kq) do { \ KQ_FLUX_WAKEUP(kq); \ mtx_unlock(&(kq)->kq_lock); \ } while (0) #define KQ_UNLOCK(kq) do { \ mtx_unlock(&(kq)->kq_lock); \ } while (0) #define KQ_OWNED(kq) do { \ mtx_assert(&(kq)->kq_lock, MA_OWNED); \ } while (0) #define KQ_NOTOWNED(kq) do { \ mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ } while (0) #define KN_LIST_LOCK(kn) do { \ if (kn->kn_knlist != NULL) \ mtx_lock(kn->kn_knlist->kl_lock); \ } while (0) #define KN_LIST_UNLOCK(kn) do { \ if (kn->kn_knlist != NULL) \ mtx_unlock(kn->kn_knlist->kl_lock); \ } while (0) #define KN_HASHSIZE 64 /* XXX should be tunable */ #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) static int filt_nullattach(struct knote *kn) { return (ENXIO); }; struct filterops null_filtops = { 0, filt_nullattach, NULL, NULL }; /* XXX - make SYSINIT to add these, and move into respective modules. */ extern struct filterops sig_filtops; extern struct filterops fs_filtops; /* * Table for for all system-defined filters. */ static struct mtx filterops_lock; MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", MTX_DEF); static struct { struct filterops *for_fop; int for_refcnt; } sysfilt_ops[EVFILT_SYSCOUNT] = { { &file_filtops }, /* EVFILT_READ */ { &file_filtops }, /* EVFILT_WRITE */ { &null_filtops }, /* EVFILT_AIO */ { &file_filtops }, /* EVFILT_VNODE */ { &proc_filtops }, /* EVFILT_PROC */ { &sig_filtops }, /* EVFILT_SIGNAL */ { &timer_filtops }, /* EVFILT_TIMER */ { &file_filtops }, /* EVFILT_NETDEV */ { &fs_filtops }, /* EVFILT_FS */ }; /* * Simple redirection for all cdevsw style objects to call their fo_kqfilter * method. */ static int filt_fileattach(struct knote *kn) { return (fo_kqfilter(kn->kn_fp, kn)); } /*ARGSUSED*/ static int kqueue_kqfilter(struct file *fp, struct knote *kn) { struct kqueue *kq = kn->kn_fp->f_data; if (kn->kn_filter != EVFILT_READ) return (EINVAL); kn->kn_status |= KN_KQUEUE; kn->kn_fop = &kqread_filtops; knlist_add(&kq->kq_sel.si_note, kn, 0); return (0); } static void filt_kqdetach(struct knote *kn) { struct kqueue *kq = kn->kn_fp->f_data; knlist_remove(&kq->kq_sel.si_note, kn, 0); } /*ARGSUSED*/ static int filt_kqueue(struct knote *kn, long hint) { struct kqueue *kq = kn->kn_fp->f_data; kn->kn_data = kq->kq_count; return (kn->kn_data > 0); } /* XXX - move to kern_proc.c? */ static int filt_procattach(struct knote *kn) { struct proc *p; int immediate; int error; immediate = 0; p = pfind(kn->kn_id); if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { p = zpfind(kn->kn_id); immediate = 1; } else if (p != NULL && (p->p_flag & P_WEXIT)) { immediate = 1; } if (p == NULL) return (ESRCH); if ((error = p_cansee(curthread, p))) return (error); kn->kn_ptr.p_proc = p; kn->kn_flags |= EV_CLEAR; /* automatically set */ /* * internal flag indicating registration done by kernel */ if (kn->kn_flags & EV_FLAG1) { kn->kn_data = kn->kn_sdata; /* ppid */ kn->kn_fflags = NOTE_CHILD; kn->kn_flags &= ~EV_FLAG1; } if (immediate == 0) knlist_add(&p->p_klist, kn, 1); /* * Immediately activate any exit notes if the target process is a * zombie. This is necessary to handle the case where the target * process, e.g. a child, dies before the kevent is registered. */ if (immediate && filt_proc(kn, NOTE_EXIT)) KNOTE_ACTIVATE(kn, 0); PROC_UNLOCK(p); return (0); } /* * The knote may be attached to a different process, which may exit, * leaving nothing for the knote to be attached to. So when the process * exits, the knote is marked as DETACHED and also flagged as ONESHOT so * it will be deleted when read out. However, as part of the knote deletion, * this routine is called, so a check is needed to avoid actually performing * a detach, because the original process does not exist any more. */ /* XXX - move to kern_proc.c? */ static void filt_procdetach(struct knote *kn) { struct proc *p; p = kn->kn_ptr.p_proc; knlist_remove(&p->p_klist, kn, 0); kn->kn_ptr.p_proc = NULL; } /* XXX - move to kern_proc.c? */ static int filt_proc(struct knote *kn, long hint) { struct proc *p = kn->kn_ptr.p_proc; u_int event; /* * mask off extra data */ event = (u_int)hint & NOTE_PCTRLMASK; /* * if the user is interested in this event, record it. */ if (kn->kn_sfflags & event) kn->kn_fflags |= event; /* * process is gone, so flag the event as finished. */ if (event == NOTE_EXIT) { if (!(kn->kn_status & KN_DETACHED)) knlist_remove_inevent(&p->p_klist, kn); kn->kn_flags |= (EV_EOF | EV_ONESHOT); kn->kn_ptr.p_proc = NULL; return (1); } /* * process forked, and user wants to track the new process, * so attach a new knote to it, and immediately report an * event with the parent's pid. */ if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) { struct kevent kev; int error; /* * register knote with new process. */ kev.ident = hint & NOTE_PDATAMASK; /* pid */ kev.filter = kn->kn_filter; kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; kev.fflags = kn->kn_sfflags; kev.data = kn->kn_id; /* parent */ kev.udata = kn->kn_kevent.udata; /* preserve udata */ error = kqueue_register(kn->kn_kq, &kev, NULL, 0); if (error) kn->kn_fflags |= NOTE_TRACKERR; } return (kn->kn_fflags != 0); } static int timertoticks(intptr_t data) { struct timeval tv; int tticks; tv.tv_sec = data / 1000; tv.tv_usec = (data % 1000) * 1000; tticks = tvtohz(&tv); return tticks; } /* XXX - move to kern_timeout.c? */ static void filt_timerexpire(void *knx) { struct knote *kn = knx; struct callout *calloutp; kn->kn_data++; KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { calloutp = (struct callout *)kn->kn_hook; callout_reset(calloutp, timertoticks(kn->kn_sdata), filt_timerexpire, kn); } } /* * data contains amount of time to sleep, in milliseconds */ /* XXX - move to kern_timeout.c? */ static int filt_timerattach(struct knote *kn) { struct callout *calloutp; atomic_add_int(&kq_ncallouts, 1); if (kq_ncallouts >= kq_calloutmax) { atomic_add_int(&kq_ncallouts, -1); return (ENOMEM); } kn->kn_flags |= EV_CLEAR; /* automatically set */ kn->kn_status &= ~KN_DETACHED; /* knlist_add usually sets it */ MALLOC(calloutp, struct callout *, sizeof(*calloutp), M_KQUEUE, M_WAITOK); callout_init(calloutp, CALLOUT_MPSAFE); kn->kn_hook = calloutp; callout_reset(calloutp, timertoticks(kn->kn_sdata), filt_timerexpire, kn); return (0); } /* XXX - move to kern_timeout.c? */ static void filt_timerdetach(struct knote *kn) { struct callout *calloutp; calloutp = (struct callout *)kn->kn_hook; callout_drain(calloutp); FREE(calloutp, M_KQUEUE); atomic_add_int(&kq_ncallouts, -1); kn->kn_status |= KN_DETACHED; /* knlist_remove usually clears it */ } /* XXX - move to kern_timeout.c? */ static int filt_timer(struct knote *kn, long hint) { return (kn->kn_data != 0); } /* * MPSAFE */ int kqueue(struct thread *td, struct kqueue_args *uap) { struct filedesc *fdp; struct kqueue *kq; struct file *fp; int fd, error; fdp = td->td_proc->p_fd; error = falloc(td, &fp, &fd); if (error) goto done2; /* An extra reference on `nfp' has been held for us by falloc(). */ kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); TAILQ_INIT(&kq->kq_head); kq->kq_fdp = fdp; knlist_init(&kq->kq_sel.si_note, &kq->kq_lock); TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); FILEDESC_LOCK_FAST(fdp); SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); FILEDESC_UNLOCK_FAST(fdp); FILE_LOCK(fp); fp->f_flag = FREAD | FWRITE; fp->f_type = DTYPE_KQUEUE; fp->f_ops = &kqueueops; fp->f_data = kq; FILE_UNLOCK(fp); fdrop(fp, td); td->td_retval[0] = fd; done2: return (error); } #ifndef _SYS_SYSPROTO_H_ struct kevent_args { int fd; const struct kevent *changelist; int nchanges; struct kevent *eventlist; int nevents; const struct timespec *timeout; }; #endif /* * MPSAFE */ int kevent(struct thread *td, struct kevent_args *uap) { struct timespec ts, *tsp; int error; if (uap->timeout != NULL) { error = copyin(uap->timeout, &ts, sizeof(ts)); if (error) return (error); tsp = &ts; } else tsp = NULL; return (kern_kevent(td, uap->fd, uap->changelist, uap->nchanges, UIO_USERSPACE, uap->eventlist, uap->nevents, UIO_USERSPACE, tsp)); } /* * Copy 'count' items into the destination list pointd to by *eventlist. The * eventlist and nevents values are updated to point after the copied out * item(s) upon return. */ static int kevent_copyout(struct kevent **eventlist, enum uio_seg eventseg, struct kevent *kevp, int count) { int error; if (eventseg == UIO_USERSPACE) error = copyout(kevp, *eventlist, sizeof(struct kevent) * count); else { bcopy(kevp, *eventlist, sizeof(struct kevent) * count); error = 0; } *eventlist += count; return (error); } int kern_kevent(struct thread *td, int fd, struct kevent *changelist, int nchanges, enum uio_seg changeseg, struct kevent *eventlist, int nevents, enum uio_seg eventseg, const struct timespec *timeout) { struct kevent keva[KQ_NEVENTS]; struct kevent *kevp, *changes; struct kqueue *kq; struct file *fp; int i, n, nerrors, error; if ((error = fget(td, fd, &fp)) != 0) return (error); if ((error = kqueue_aquire(fp, &kq)) != 0) goto done_norel; nerrors = 0; while (nchanges > 0) { if (changeseg == UIO_USERSPACE) { n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; error = copyin(changelist, keva, n * sizeof *keva); if (error) goto done; changes = keva; } else { changes = changelist; n = nchanges; } for (i = 0; i < n; i++) { kevp = &changes[i]; kevp->flags &= ~EV_SYSFLAGS; error = kqueue_register(kq, kevp, td, 1); if (error) { if (nevents != 0) { kevp->flags = EV_ERROR; kevp->data = error; (void) kevent_copyout(&eventlist, eventseg, kevp, 1); nevents--; nerrors++; } else { goto done; } } } nchanges -= n; changelist += n; } if (nerrors) { td->td_retval[0] = nerrors; error = 0; goto done; } error = kqueue_scan(kq, nevents, eventlist, eventseg, timeout, keva, td); done: kqueue_release(kq, 0); done_norel: if (fp != NULL) fdrop(fp, td); return (error); } int kqueue_add_filteropts(int filt, struct filterops *filtops) { int error; if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { printf( "trying to add a filterop that is out of range: %d is beyond %d\n", ~filt, EVFILT_SYSCOUNT); return EINVAL; } mtx_lock(&filterops_lock); if (sysfilt_ops[~filt].for_fop != &null_filtops && sysfilt_ops[~filt].for_fop != NULL) error = EEXIST; else { sysfilt_ops[~filt].for_fop = filtops; sysfilt_ops[~filt].for_refcnt = 0; } mtx_unlock(&filterops_lock); return (0); } int kqueue_del_filteropts(int filt) { int error; error = 0; if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) return EINVAL; mtx_lock(&filterops_lock); if (sysfilt_ops[~filt].for_fop == &null_filtops || sysfilt_ops[~filt].for_fop == NULL) error = EINVAL; else if (sysfilt_ops[~filt].for_refcnt != 0) error = EBUSY; else { sysfilt_ops[~filt].for_fop = &null_filtops; sysfilt_ops[~filt].for_refcnt = 0; } mtx_unlock(&filterops_lock); return error; } static struct filterops * kqueue_fo_find(int filt) { if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) return NULL; mtx_lock(&filterops_lock); sysfilt_ops[~filt].for_refcnt++; if (sysfilt_ops[~filt].for_fop == NULL) sysfilt_ops[~filt].for_fop = &null_filtops; mtx_unlock(&filterops_lock); return sysfilt_ops[~filt].for_fop; } static void kqueue_fo_release(int filt) { if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) return; mtx_lock(&filterops_lock); KASSERT(sysfilt_ops[~filt].for_refcnt > 0, ("filter object refcount not valid on release")); sysfilt_ops[~filt].for_refcnt--; mtx_unlock(&filterops_lock); } /* * A ref to kq (obtained via kqueue_aquire) should be held. waitok will * influence if memory allocation should wait. Make sure it is 0 if you * hold any mutexes. */ int kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) { struct filedesc *fdp; struct filterops *fops; struct file *fp; struct knote *kn, *tkn; int error, filt, event; int haskqglobal; int fd; fdp = NULL; fp = NULL; kn = NULL; error = 0; haskqglobal = 0; filt = kev->filter; fops = kqueue_fo_find(filt); if (fops == NULL) return EINVAL; tkn = knote_alloc(waitok); /* prevent waiting with locks */ findkn: if (fops->f_isfd) { KASSERT(td != NULL, ("td is NULL")); fdp = td->td_proc->p_fd; FILEDESC_LOCK(fdp); /* validate descriptor */ fd = kev->ident; if (fd < 0 || fd >= fdp->fd_nfiles || (fp = fdp->fd_ofiles[fd]) == NULL) { FILEDESC_UNLOCK(fdp); error = EBADF; goto done; } fhold(fp); if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, kev->ident, 0) != 0) { /* unlock and try again */ FILEDESC_UNLOCK(fdp); fdrop(fp, td); fp = NULL; error = kqueue_expand(kq, fops, kev->ident, waitok); if (error) goto done; goto findkn; } if (fp->f_type == DTYPE_KQUEUE) { /* * if we add some inteligence about what we are doing, * we should be able to support events on ourselves. * We need to know when we are doing this to prevent * getting both the knlist lock and the kq lock since * they are the same thing. */ if (fp->f_data == kq) { FILEDESC_UNLOCK(fdp); error = EINVAL; goto done_noglobal; } KQ_GLOBAL_LOCK(&kq_global, haskqglobal); } FILEDESC_UNLOCK(fdp); KQ_LOCK(kq); if (kev->ident < kq->kq_knlistsize) { SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) if (kev->filter == kn->kn_filter) break; } } else { if ((kev->flags & EV_ADD) == EV_ADD) kqueue_expand(kq, fops, kev->ident, waitok); KQ_LOCK(kq); if (kq->kq_knhashmask != 0) { struct klist *list; list = &kq->kq_knhash[ KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; SLIST_FOREACH(kn, list, kn_link) if (kev->ident == kn->kn_id && kev->filter == kn->kn_filter) break; } } /* knote is in the process of changing, wait for it to stablize. */ if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { if (fp != NULL) { fdrop(fp, td); fp = NULL; } KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); kq->kq_state |= KQ_FLUXWAIT; msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); goto findkn; } if (kn == NULL && ((kev->flags & EV_ADD) == 0)) { KQ_UNLOCK(kq); error = ENOENT; goto done; } /* * kn now contains the matching knote, or NULL if no match */ if (kev->flags & EV_ADD) { if (kn == NULL) { kn = tkn; tkn = NULL; if (kn == NULL) { error = ENOMEM; goto done; } kn->kn_fp = fp; kn->kn_kq = kq; kn->kn_fop = fops; /* * apply reference counts to knote structure, and * do not release it at the end of this routine. */ fops = NULL; fp = NULL; kn->kn_sfflags = kev->fflags; kn->kn_sdata = kev->data; kev->fflags = 0; kev->data = 0; kn->kn_kevent = *kev; kn->kn_status = KN_INFLUX|KN_DETACHED; error = knote_attach(kn, kq); KQ_UNLOCK(kq); if (error != 0) { tkn = kn; goto done; } if ((error = kn->kn_fop->f_attach(kn)) != 0) { knote_drop(kn, td); goto done; } KN_LIST_LOCK(kn); } else { /* * The user may change some filter values after the * initial EV_ADD, but doing so will not reset any * filter which has already been triggered. */ kn->kn_status |= KN_INFLUX; KQ_UNLOCK(kq); KN_LIST_LOCK(kn); kn->kn_sfflags = kev->fflags; kn->kn_sdata = kev->data; kn->kn_kevent.udata = kev->udata; } /* * We can get here with kn->kn_knlist == NULL. * This can happen when the initial attach event decides that * the event is "completed" already. i.e. filt_procattach * is called on a zombie process. It will call filt_proc * which will remove it from the list, and NULL kn_knlist. */ event = kn->kn_fop->f_event(kn, 0); KN_LIST_UNLOCK(kn); KQ_LOCK(kq); if (event) KNOTE_ACTIVATE(kn, 1); kn->kn_status &= ~KN_INFLUX; } else if (kev->flags & EV_DELETE) { kn->kn_status |= KN_INFLUX; KQ_UNLOCK(kq); if (!(kn->kn_status & KN_DETACHED)) kn->kn_fop->f_detach(kn); knote_drop(kn, td); goto done; } if ((kev->flags & EV_DISABLE) && ((kn->kn_status & KN_DISABLED) == 0)) { kn->kn_status |= KN_DISABLED; } if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { kn->kn_status &= ~KN_DISABLED; if ((kn->kn_status & KN_ACTIVE) && ((kn->kn_status & KN_QUEUED) == 0)) knote_enqueue(kn); } KQ_UNLOCK_FLUX(kq); done: KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); done_noglobal: if (fp != NULL) fdrop(fp, td); if (tkn != NULL) knote_free(tkn); if (fops != NULL) kqueue_fo_release(filt); return (error); } static int kqueue_aquire(struct file *fp, struct kqueue **kqp) { int error; struct kqueue *kq; error = 0; FILE_LOCK(fp); do { kq = fp->f_data; if (fp->f_type != DTYPE_KQUEUE || kq == NULL) { error = EBADF; break; } *kqp = kq; KQ_LOCK(kq); if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { KQ_UNLOCK(kq); error = EBADF; break; } kq->kq_refcnt++; KQ_UNLOCK(kq); } while (0); FILE_UNLOCK(fp); return error; } static void kqueue_release(struct kqueue *kq, int locked) { if (locked) KQ_OWNED(kq); else KQ_LOCK(kq); kq->kq_refcnt--; if (kq->kq_refcnt == 1) wakeup(&kq->kq_refcnt); if (!locked) KQ_UNLOCK(kq); } static void kqueue_schedtask(struct kqueue *kq) { KQ_OWNED(kq); KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), ("scheduling kqueue task while draining")); if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); kq->kq_state |= KQ_TASKSCHED; } } /* * Expand the kq to make sure we have storage for fops/ident pair. * * Return 0 on success (or no work necessary), return errno on failure. * * Not calling hashinit w/ waitok (proper malloc flag) should be safe. * If kqueue_register is called from a non-fd context, there usually/should * be no locks held. */ static int kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, int waitok) { struct klist *list, *tmp_knhash; u_long tmp_knhashmask; int size; int fd; int mflag = waitok ? M_WAITOK : M_NOWAIT; KQ_NOTOWNED(kq); if (fops->f_isfd) { fd = ident; if (kq->kq_knlistsize <= fd) { size = kq->kq_knlistsize; while (size <= fd) size += KQEXTENT; MALLOC(list, struct klist *, size * sizeof list, M_KQUEUE, mflag); if (list == NULL) return ENOMEM; KQ_LOCK(kq); if (kq->kq_knlistsize > fd) { FREE(list, M_KQUEUE); list = NULL; } else { if (kq->kq_knlist != NULL) { bcopy(kq->kq_knlist, list, kq->kq_knlistsize * sizeof list); FREE(kq->kq_knlist, M_KQUEUE); kq->kq_knlist = NULL; } bzero((caddr_t)list + kq->kq_knlistsize * sizeof list, (size - kq->kq_knlistsize) * sizeof list); kq->kq_knlistsize = size; kq->kq_knlist = list; } KQ_UNLOCK(kq); } } else { if (kq->kq_knhashmask == 0) { tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, &tmp_knhashmask); if (tmp_knhash == NULL) return ENOMEM; KQ_LOCK(kq); if (kq->kq_knhashmask == 0) { kq->kq_knhash = tmp_knhash; kq->kq_knhashmask = tmp_knhashmask; } else { free(tmp_knhash, M_KQUEUE); } KQ_UNLOCK(kq); } } KQ_NOTOWNED(kq); return 0; } static void kqueue_task(void *arg, int pending) { struct kqueue *kq; int haskqglobal; haskqglobal = 0; kq = arg; KQ_GLOBAL_LOCK(&kq_global, haskqglobal); KQ_LOCK(kq); KNOTE_LOCKED(&kq->kq_sel.si_note, 0); kq->kq_state &= ~KQ_TASKSCHED; if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { wakeup(&kq->kq_state); } KQ_UNLOCK(kq); KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); } /* * Scan, update kn_data (if not ONESHOT), and copyout triggered events. * We treat KN_MARKER knotes as if they are INFLUX. */ static int kqueue_scan(struct kqueue *kq, int maxevents, struct kevent *eventlist, enum uio_seg eventseg, const struct timespec *tsp, struct kevent *keva, struct thread *td) { struct kevent *kevp; struct timeval atv, rtv, ttv; struct knote *kn, *marker; int count, timeout, nkev, error; int haskqglobal; count = maxevents; nkev = 0; error = 0; haskqglobal = 0; if (maxevents == 0) goto done_nl; if (tsp != NULL) { TIMESPEC_TO_TIMEVAL(&atv, tsp); if (itimerfix(&atv)) { error = EINVAL; goto done_nl; } if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) timeout = -1; else timeout = atv.tv_sec > 24 * 60 * 60 ? 24 * 60 * 60 * hz : tvtohz(&atv); getmicrouptime(&rtv); timevaladd(&atv, &rtv); } else { atv.tv_sec = 0; atv.tv_usec = 0; timeout = 0; } marker = knote_alloc(1); if (marker == NULL) { error = ENOMEM; goto done_nl; } marker->kn_status = KN_MARKER; KQ_LOCK(kq); goto start; retry: if (atv.tv_sec || atv.tv_usec) { getmicrouptime(&rtv); if (timevalcmp(&rtv, &atv, >=)) goto done; ttv = atv; timevalsub(&ttv, &rtv); timeout = ttv.tv_sec > 24 * 60 * 60 ? 24 * 60 * 60 * hz : tvtohz(&ttv); } start: kevp = keva; if (kq->kq_count == 0) { if (timeout < 0) { error = EWOULDBLOCK; } else { KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); kq->kq_state |= KQ_SLEEP; error = msleep(kq, &kq->kq_lock, PSOCK | PCATCH, "kqread", timeout); } if (error == 0) goto retry; /* don't restart after signals... */ if (error == ERESTART) error = EINTR; else if (error == EWOULDBLOCK) error = 0; goto done; } TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); while (count) { KQ_OWNED(kq); kn = TAILQ_FIRST(&kq->kq_head); if ((kn->kn_status == KN_MARKER && kn != marker) || (kn->kn_status & KN_INFLUX) == KN_INFLUX) { KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); kq->kq_state |= KQ_FLUXWAIT; error = msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); continue; } TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { kn->kn_status &= ~KN_QUEUED; kq->kq_count--; continue; } if (kn == marker) { KQ_FLUX_WAKEUP(kq); if (count == maxevents) goto retry; goto done; } KASSERT((kn->kn_status & KN_INFLUX) == 0, ("KN_INFLUX set when not suppose to be")); if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { kn->kn_status &= ~KN_QUEUED; kn->kn_status |= KN_INFLUX; kq->kq_count--; KQ_UNLOCK(kq); /* * We don't need to lock the list since we've marked * it _INFLUX. */ *kevp = kn->kn_kevent; if (!(kn->kn_status & KN_DETACHED)) kn->kn_fop->f_detach(kn); knote_drop(kn, td); KQ_LOCK(kq); kn = NULL; } else { kn->kn_status |= KN_INFLUX; KQ_UNLOCK(kq); if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) KQ_GLOBAL_LOCK(&kq_global, haskqglobal); KN_LIST_LOCK(kn); if (kn->kn_fop->f_event(kn, 0) == 0) { KN_LIST_UNLOCK(kn); KQ_LOCK(kq); kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); kq->kq_count--; continue; } *kevp = kn->kn_kevent; KQ_LOCK(kq); if (kn->kn_flags & EV_CLEAR) { kn->kn_data = 0; kn->kn_fflags = 0; kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); kq->kq_count--; } else TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); KN_LIST_UNLOCK(kn); kn->kn_status &= ~(KN_INFLUX); } /* we are returning a copy to the user */ kevp++; nkev++; count--; if (nkev == KQ_NEVENTS) { KQ_UNLOCK_FLUX(kq); error = kevent_copyout(&eventlist, eventseg, keva, nkev); nkev = 0; kevp = keva; KQ_LOCK(kq); if (error) break; } } TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); done: KQ_OWNED(kq); KQ_UNLOCK_FLUX(kq); KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); knote_free(marker); done_nl: KQ_NOTOWNED(kq); if (nkev != 0) error = kevent_copyout(&eventlist, eventseg, keva, nkev); td->td_retval[0] = maxevents - count; return (error); } /* * XXX * This could be expanded to call kqueue_scan, if desired. */ /*ARGSUSED*/ static int kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td) { return (ENXIO); } /*ARGSUSED*/ static int kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td) { return (ENXIO); } /*ARGSUSED*/ static int kqueue_ioctl(struct file *fp, u_long cmd, void *data, struct ucred *active_cred, struct thread *td) { /* * Enabling sigio causes two major problems: * 1) infinite recursion: * Synopsys: kevent is being used to track signals and have FIOASYNC * set. On receipt of a signal this will cause a kqueue to recurse * into itself over and over. Sending the sigio causes the kqueue * to become ready, which in turn posts sigio again, forever. * Solution: this can be solved by setting a flag in the kqueue that * we have a SIGIO in progress. * 2) locking problems: * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts * us above the proc and pgrp locks. * Solution: Post a signal using an async mechanism, being sure to * record a generation count in the delivery so that we do not deliver * a signal to the wrong process. * * Note, these two mechanisms are somewhat mutually exclusive! */ #if 0 struct kqueue *kq; kq = fp->f_data; switch (cmd) { case FIOASYNC: if (*(int *)data) { kq->kq_state |= KQ_ASYNC; } else { kq->kq_state &= ~KQ_ASYNC; } return (0); case FIOSETOWN: return (fsetown(*(int *)data, &kq->kq_sigio)); case FIOGETOWN: *(int *)data = fgetown(&kq->kq_sigio); return (0); } #endif return (ENOTTY); } /*ARGSUSED*/ static int kqueue_poll(struct file *fp, int events, struct ucred *active_cred, struct thread *td) { struct kqueue *kq; int revents = 0; int error; if ((error = kqueue_aquire(fp, &kq))) return POLLERR; KQ_LOCK(kq); if (events & (POLLIN | POLLRDNORM)) { if (kq->kq_count) { revents |= events & (POLLIN | POLLRDNORM); } else { selrecord(td, &kq->kq_sel); kq->kq_state |= KQ_SEL; } } kqueue_release(kq, 1); KQ_UNLOCK(kq); return (revents); } /*ARGSUSED*/ static int kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, struct thread *td) { return (ENXIO); } /*ARGSUSED*/ static int kqueue_close(struct file *fp, struct thread *td) { struct kqueue *kq = fp->f_data; struct filedesc *fdp; struct knote *kn; int i; int error; if ((error = kqueue_aquire(fp, &kq))) return error; KQ_LOCK(kq); KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, ("kqueue already closing")); kq->kq_state |= KQ_CLOSING; if (kq->kq_refcnt > 1) msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); fdp = kq->kq_fdp; KASSERT(knlist_empty(&kq->kq_sel.si_note), ("kqueue's knlist not empty")); for (i = 0; i < kq->kq_knlistsize; i++) { while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { KASSERT((kn->kn_status & KN_INFLUX) == 0, ("KN_INFLUX set when not suppose to be")); kn->kn_status |= KN_INFLUX; KQ_UNLOCK(kq); if (!(kn->kn_status & KN_DETACHED)) kn->kn_fop->f_detach(kn); knote_drop(kn, td); KQ_LOCK(kq); } } if (kq->kq_knhashmask != 0) { for (i = 0; i <= kq->kq_knhashmask; i++) { while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { KASSERT((kn->kn_status & KN_INFLUX) == 0, ("KN_INFLUX set when not suppose to be")); kn->kn_status |= KN_INFLUX; KQ_UNLOCK(kq); if (!(kn->kn_status & KN_DETACHED)) kn->kn_fop->f_detach(kn); knote_drop(kn, td); KQ_LOCK(kq); } } } if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { kq->kq_state |= KQ_TASKDRAIN; msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); } if ((kq->kq_state & KQ_SEL) == KQ_SEL) { kq->kq_state &= ~KQ_SEL; selwakeuppri(&kq->kq_sel, PSOCK); } KQ_UNLOCK(kq); FILEDESC_LOCK_FAST(fdp); SLIST_REMOVE(&fdp->fd_kqlist, kq, kqueue, kq_list); FILEDESC_UNLOCK_FAST(fdp); knlist_destroy(&kq->kq_sel.si_note); mtx_destroy(&kq->kq_lock); kq->kq_fdp = NULL; if (kq->kq_knhash != NULL) free(kq->kq_knhash, M_KQUEUE); if (kq->kq_knlist != NULL) free(kq->kq_knlist, M_KQUEUE); funsetown(&kq->kq_sigio); free(kq, M_KQUEUE); fp->f_data = NULL; return (0); } static void kqueue_wakeup(struct kqueue *kq) { KQ_OWNED(kq); if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { kq->kq_state &= ~KQ_SLEEP; wakeup(kq); } if ((kq->kq_state & KQ_SEL) == KQ_SEL) { kq->kq_state &= ~KQ_SEL; selwakeuppri(&kq->kq_sel, PSOCK); } if (!knlist_empty(&kq->kq_sel.si_note)) kqueue_schedtask(kq); if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { pgsigio(&kq->kq_sigio, SIGIO, 0); } } /* * Walk down a list of knotes, activating them if their event has triggered. * * There is a possibility to optimize in the case of one kq watching another. * Instead of scheduling a task to wake it up, you could pass enough state * down the chain to make up the parent kqueue. Make this code functional * first. */ void knote(struct knlist *list, long hint, int islocked) { struct kqueue *kq; struct knote *kn; if (list == NULL) return; mtx_assert(list->kl_lock, islocked ? MA_OWNED : MA_NOTOWNED); if (!islocked) mtx_lock(list->kl_lock); /* * If we unlock the list lock (and set KN_INFLUX), we can eliminate * the kqueue scheduling, but this will introduce four * lock/unlock's for each knote to test. If we do, continue to use * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is * only safe if you want to remove the current item, which we are * not doing. */ SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { kq = kn->kn_kq; if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { KQ_LOCK(kq); if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { kn->kn_status |= KN_HASKQLOCK; if (kn->kn_fop->f_event(kn, hint)) KNOTE_ACTIVATE(kn, 1); kn->kn_status &= ~KN_HASKQLOCK; } KQ_UNLOCK(kq); } kq = NULL; } if (!islocked) mtx_unlock(list->kl_lock); } /* * add a knote to a knlist */ void knlist_add(struct knlist *knl, struct knote *kn, int islocked) { mtx_assert(knl->kl_lock, islocked ? MA_OWNED : MA_NOTOWNED); KQ_NOTOWNED(kn->kn_kq); KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); if (!islocked) mtx_lock(knl->kl_lock); SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); if (!islocked) mtx_unlock(knl->kl_lock); KQ_LOCK(kn->kn_kq); kn->kn_knlist = knl; kn->kn_status &= ~KN_DETACHED; KQ_UNLOCK(kn->kn_kq); } static void knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) { KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); mtx_assert(knl->kl_lock, knlislocked ? MA_OWNED : MA_NOTOWNED); mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); if (!kqislocked) KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, ("knlist_remove called w/o knote being KN_INFLUX or already removed")); if (!knlislocked) mtx_lock(knl->kl_lock); SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); kn->kn_knlist = NULL; if (!knlislocked) mtx_unlock(knl->kl_lock); if (!kqislocked) KQ_LOCK(kn->kn_kq); kn->kn_status |= KN_DETACHED; if (!kqislocked) KQ_UNLOCK(kn->kn_kq); } /* * remove all knotes from a specified klist */ void knlist_remove(struct knlist *knl, struct knote *kn, int islocked) { knlist_remove_kq(knl, kn, islocked, 0); } /* * remove knote from a specified klist while in f_event handler. */ void knlist_remove_inevent(struct knlist *knl, struct knote *kn) { knlist_remove_kq(knl, kn, 1, (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); } int knlist_empty(struct knlist *knl) { mtx_assert(knl->kl_lock, MA_OWNED); return SLIST_EMPTY(&knl->kl_list); } static struct mtx knlist_lock; MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", MTX_DEF); void knlist_init(struct knlist *knl, struct mtx *mtx) { if (mtx == NULL) knl->kl_lock = &knlist_lock; else knl->kl_lock = mtx; SLIST_INIT(&knl->kl_list); } void knlist_destroy(struct knlist *knl) { #ifdef INVARIANTS /* * if we run across this error, we need to find the offending * driver and have it call knlist_clear. */ if (!SLIST_EMPTY(&knl->kl_list)) printf("WARNING: destroying knlist w/ knotes on it!\n"); #endif knl->kl_lock = NULL; SLIST_INIT(&knl->kl_list); } /* * Even if we are locked, we may need to drop the lock to allow any influx * knotes time to "settle". */ void knlist_clear(struct knlist *knl, int islocked) { struct knote *kn; struct kqueue *kq; if (islocked) mtx_assert(knl->kl_lock, MA_OWNED); else { mtx_assert(knl->kl_lock, MA_NOTOWNED); again: /* need to reaquire lock since we have dropped it */ mtx_lock(knl->kl_lock); } SLIST_FOREACH(kn, &knl->kl_list, kn_selnext) { kq = kn->kn_kq; KQ_LOCK(kq); if ((kn->kn_status & KN_INFLUX) && (kn->kn_status & KN_DETACHED) != KN_DETACHED) { KQ_UNLOCK(kq); continue; } /* Make sure cleared knotes disappear soon */ kn->kn_flags |= (EV_EOF | EV_ONESHOT); knlist_remove_kq(knl, kn, 1, 1); KQ_UNLOCK(kq); kq = NULL; } if (!SLIST_EMPTY(&knl->kl_list)) { /* there are still KN_INFLUX remaining */ kn = SLIST_FIRST(&knl->kl_list); kq = kn->kn_kq; KQ_LOCK(kq); KASSERT(kn->kn_status & KN_INFLUX, ("knote removed w/o list lock")); mtx_unlock(knl->kl_lock); kq->kq_state |= KQ_FLUXWAIT; msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); kq = NULL; goto again; } SLIST_INIT(&knl->kl_list); if (islocked) mtx_assert(knl->kl_lock, MA_OWNED); else { mtx_unlock(knl->kl_lock); mtx_assert(knl->kl_lock, MA_NOTOWNED); } } /* * remove all knotes referencing a specified fd * must be called with FILEDESC lock. This prevents a race where a new fd * comes along and occupies the entry and we attach a knote to the fd. */ void knote_fdclose(struct thread *td, int fd) { struct filedesc *fdp = td->td_proc->p_fd; struct kqueue *kq; struct knote *kn; int influx; FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); /* * We shouldn't have to worry about new kevents appearing on fd * since filedesc is locked. */ SLIST_FOREACH(kq, &fdp->fd_kqlist, kq_list) { KQ_LOCK(kq); again: influx = 0; while (kq->kq_knlistsize > fd && (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { if (kn->kn_status & KN_INFLUX) { /* someone else might be waiting on our knote */ if (influx) wakeup(kq); kq->kq_state |= KQ_FLUXWAIT; msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); goto again; } kn->kn_status |= KN_INFLUX; KQ_UNLOCK(kq); if (!(kn->kn_status & KN_DETACHED)) kn->kn_fop->f_detach(kn); knote_drop(kn, td); influx = 1; KQ_LOCK(kq); } KQ_UNLOCK_FLUX(kq); } } static int knote_attach(struct knote *kn, struct kqueue *kq) { struct klist *list; KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); KQ_OWNED(kq); if (kn->kn_fop->f_isfd) { if (kn->kn_id >= kq->kq_knlistsize) return ENOMEM; list = &kq->kq_knlist[kn->kn_id]; } else { if (kq->kq_knhash == NULL) return ENOMEM; list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; } SLIST_INSERT_HEAD(list, kn, kn_link); return 0; } /* * knote must already have been detatched using the f_detach method. * no lock need to be held, it is assumed that the KN_INFLUX flag is set * to prevent other removal. */ static void knote_drop(struct knote *kn, struct thread *td) { struct kqueue *kq; struct klist *list; kq = kn->kn_kq; KQ_NOTOWNED(kq); KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, ("knote_drop called without KN_INFLUX set in kn_status")); KQ_LOCK(kq); if (kn->kn_fop->f_isfd) list = &kq->kq_knlist[kn->kn_id]; else list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; SLIST_REMOVE(list, kn, knote, kn_link); if (kn->kn_status & KN_QUEUED) knote_dequeue(kn); KQ_UNLOCK_FLUX(kq); if (kn->kn_fop->f_isfd) { fdrop(kn->kn_fp, td); kn->kn_fp = NULL; } kqueue_fo_release(kn->kn_kevent.filter); kn->kn_fop = NULL; knote_free(kn); } static void knote_enqueue(struct knote *kn) { struct kqueue *kq = kn->kn_kq; KQ_OWNED(kn->kn_kq); KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); kn->kn_status |= KN_QUEUED; kq->kq_count++; kqueue_wakeup(kq); } static void knote_dequeue(struct knote *kn) { struct kqueue *kq = kn->kn_kq; KQ_OWNED(kn->kn_kq); KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); kn->kn_status &= ~KN_QUEUED; kq->kq_count--; } static void knote_init(void) { knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); } SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL) static struct knote * knote_alloc(int waitok) { return ((struct knote *)uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); } static void knote_free(struct knote *kn) { if (kn != NULL) uma_zfree(knote_zone, kn); }