/* $OpenBSD: kern_event.c,v 1.160 2021/01/27 02:58:03 visa Exp $ */ /*- * 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 1.22 2001/02/23 20:32:42 jlemon 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 #include #include #ifdef DIAGNOSTIC #define KLIST_ASSERT_LOCKED(kl) do { \ if ((kl)->kl_ops != NULL) \ (kl)->kl_ops->klo_assertlk((kl)->kl_arg); \ else \ KERNEL_ASSERT_LOCKED(); \ } while (0) #else #define KLIST_ASSERT_LOCKED(kl) ((void)(kl)) #endif struct kqueue *kqueue_alloc(struct filedesc *); void kqueue_terminate(struct proc *p, struct kqueue *); void kqueue_init(void); void KQREF(struct kqueue *); void KQRELE(struct kqueue *); int kqueue_sleep(struct kqueue *, struct timespec *); int kqueue_read(struct file *, struct uio *, int); int kqueue_write(struct file *, struct uio *, int); int kqueue_ioctl(struct file *fp, u_long com, caddr_t data, struct proc *p); int kqueue_poll(struct file *fp, int events, struct proc *p); int kqueue_kqfilter(struct file *fp, struct knote *kn); int kqueue_stat(struct file *fp, struct stat *st, struct proc *p); int kqueue_close(struct file *fp, struct proc *p); void kqueue_wakeup(struct kqueue *kq); #ifdef KQUEUE_DEBUG void kqueue_do_check(struct kqueue *kq, const char *func, int line); #define kqueue_check(kq) kqueue_do_check((kq), __func__, __LINE__) #else #define kqueue_check(kq) do {} while (0) #endif void kqpoll_dequeue(struct proc *p); static void kqueue_expand_hash(struct kqueue *kq); static void kqueue_expand_list(struct kqueue *kq, int fd); static void kqueue_task(void *); static int klist_lock(struct klist *); static void klist_unlock(struct klist *, int); const 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 }; void knote_attach(struct knote *kn); void knote_detach(struct knote *kn); void knote_drop(struct knote *kn, struct proc *p); void knote_enqueue(struct knote *kn); void knote_dequeue(struct knote *kn); int knote_acquire(struct knote *kn, struct klist *, int); void knote_release(struct knote *kn); void knote_activate(struct knote *kn); void knote_remove(struct proc *p, struct knlist *list, int purge); void filt_kqdetach(struct knote *kn); int filt_kqueue(struct knote *kn, long hint); int filt_procattach(struct knote *kn); void filt_procdetach(struct knote *kn); int filt_proc(struct knote *kn, long hint); int filt_fileattach(struct knote *kn); void filt_timerexpire(void *knx); int filt_timerattach(struct knote *kn); void filt_timerdetach(struct knote *kn); int filt_timer(struct knote *kn, long hint); void filt_seltruedetach(struct knote *kn); const struct filterops kqread_filtops = { .f_flags = FILTEROP_ISFD, .f_attach = NULL, .f_detach = filt_kqdetach, .f_event = filt_kqueue, }; const struct filterops proc_filtops = { .f_flags = 0, .f_attach = filt_procattach, .f_detach = filt_procdetach, .f_event = filt_proc, }; const struct filterops file_filtops = { .f_flags = FILTEROP_ISFD, .f_attach = filt_fileattach, .f_detach = NULL, .f_event = NULL, }; const struct filterops timer_filtops = { .f_flags = 0, .f_attach = filt_timerattach, .f_detach = filt_timerdetach, .f_event = filt_timer, }; struct pool knote_pool; struct pool kqueue_pool; int kq_ntimeouts = 0; int kq_timeoutmax = (4 * 1024); #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) /* * Table for for all system-defined filters. */ const struct filterops *const sysfilt_ops[] = { &file_filtops, /* EVFILT_READ */ &file_filtops, /* EVFILT_WRITE */ NULL, /*&aio_filtops,*/ /* EVFILT_AIO */ &file_filtops, /* EVFILT_VNODE */ &proc_filtops, /* EVFILT_PROC */ &sig_filtops, /* EVFILT_SIGNAL */ &timer_filtops, /* EVFILT_TIMER */ &file_filtops, /* EVFILT_DEVICE */ &file_filtops, /* EVFILT_EXCEPT */ }; void KQREF(struct kqueue *kq) { atomic_inc_int(&kq->kq_refs); } void KQRELE(struct kqueue *kq) { struct filedesc *fdp; if (atomic_dec_int_nv(&kq->kq_refs) > 0) return; fdp = kq->kq_fdp; if (rw_status(&fdp->fd_lock) == RW_WRITE) { LIST_REMOVE(kq, kq_next); } else { fdplock(fdp); LIST_REMOVE(kq, kq_next); fdpunlock(fdp); } KASSERT(TAILQ_EMPTY(&kq->kq_head)); free(kq->kq_knlist, M_KEVENT, kq->kq_knlistsize * sizeof(struct knlist)); hashfree(kq->kq_knhash, KN_HASHSIZE, M_KEVENT); pool_put(&kqueue_pool, kq); } void kqueue_init(void) { pool_init(&kqueue_pool, sizeof(struct kqueue), 0, IPL_MPFLOOR, PR_WAITOK, "kqueuepl", NULL); pool_init(&knote_pool, sizeof(struct knote), 0, IPL_MPFLOOR, PR_WAITOK, "knotepl", NULL); } int filt_fileattach(struct knote *kn) { struct file *fp = kn->kn_fp; return fp->f_ops->fo_kqfilter(fp, kn); } 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_fop = &kqread_filtops; klist_insert_locked(&kq->kq_sel.si_note, kn); return (0); } void filt_kqdetach(struct knote *kn) { struct kqueue *kq = kn->kn_fp->f_data; klist_remove_locked(&kq->kq_sel.si_note, kn); } 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); } int filt_procattach(struct knote *kn) { struct process *pr; int s; if ((curproc->p_p->ps_flags & PS_PLEDGE) && (curproc->p_p->ps_pledge & PLEDGE_PROC) == 0) return pledge_fail(curproc, EPERM, PLEDGE_PROC); if (kn->kn_id > PID_MAX) return ESRCH; pr = prfind(kn->kn_id); if (pr == NULL) return (ESRCH); /* exiting processes can't be specified */ if (pr->ps_flags & PS_EXITING) return (ESRCH); kn->kn_ptr.p_process = pr; 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; } s = splhigh(); klist_insert_locked(&pr->ps_klist, kn); splx(s); 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. */ void filt_procdetach(struct knote *kn) { struct process *pr = kn->kn_ptr.p_process; int s; if (kn->kn_status & KN_DETACHED) return; s = splhigh(); klist_remove_locked(&pr->ps_klist, kn); splx(s); } 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 and remove it * from the process's klist */ if (event == NOTE_EXIT) { struct process *pr = kn->kn_ptr.p_process; int s; s = splhigh(); kn->kn_status |= KN_DETACHED; kn->kn_flags |= (EV_EOF | EV_ONESHOT); kn->kn_data = W_EXITCODE(pr->ps_xexit, pr->ps_xsig); klist_remove_locked(&pr->ps_klist, kn); splx(s); 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. */ 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 */ error = kqueue_register(kn->kn_kq, &kev, NULL); if (error) kn->kn_fflags |= NOTE_TRACKERR; } return (kn->kn_fflags != 0); } static void filt_timer_timeout_add(struct knote *kn) { struct timeval tv; struct timeout *to = kn->kn_hook; int tticks; tv.tv_sec = kn->kn_sdata / 1000; tv.tv_usec = (kn->kn_sdata % 1000) * 1000; tticks = tvtohz(&tv); /* Remove extra tick from tvtohz() if timeout has fired before. */ if (timeout_triggered(to)) tticks--; timeout_add(to, (tticks > 0) ? tticks : 1); } void filt_timerexpire(void *knx) { struct knote *kn = knx; kn->kn_data++; knote_activate(kn); if ((kn->kn_flags & EV_ONESHOT) == 0) filt_timer_timeout_add(kn); } /* * data contains amount of time to sleep, in milliseconds */ int filt_timerattach(struct knote *kn) { struct timeout *to; if (kq_ntimeouts > kq_timeoutmax) return (ENOMEM); kq_ntimeouts++; kn->kn_flags |= EV_CLEAR; /* automatically set */ to = malloc(sizeof(*to), M_KEVENT, M_WAITOK); timeout_set(to, filt_timerexpire, kn); kn->kn_hook = to; filt_timer_timeout_add(kn); return (0); } void filt_timerdetach(struct knote *kn) { struct timeout *to; to = (struct timeout *)kn->kn_hook; timeout_del(to); free(to, M_KEVENT, sizeof(*to)); kq_ntimeouts--; } int filt_timer(struct knote *kn, long hint) { return (kn->kn_data != 0); } /* * filt_seltrue: * * This filter "event" routine simulates seltrue(). */ int filt_seltrue(struct knote *kn, long hint) { /* * We don't know how much data can be read/written, * but we know that it *can* be. This is about as * good as select/poll does as well. */ kn->kn_data = 0; return (1); } /* * This provides full kqfilter entry for device switch tables, which * has same effect as filter using filt_seltrue() as filter method. */ void filt_seltruedetach(struct knote *kn) { /* Nothing to do */ } const struct filterops seltrue_filtops = { .f_flags = FILTEROP_ISFD, .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); } static int filt_dead(struct knote *kn, long hint) { kn->kn_flags |= (EV_EOF | EV_ONESHOT); if (kn->kn_flags & __EV_POLL) kn->kn_flags |= __EV_HUP; kn->kn_data = 0; return (1); } static void filt_deaddetach(struct knote *kn) { /* Nothing to do */ } const struct filterops dead_filtops = { .f_flags = FILTEROP_ISFD, .f_attach = NULL, .f_detach = filt_deaddetach, .f_event = filt_dead, }; static int filt_badfd(struct knote *kn, long hint) { kn->kn_flags |= (EV_ERROR | EV_ONESHOT); kn->kn_data = EBADF; return (1); } /* For use with kqpoll. */ const struct filterops badfd_filtops = { .f_flags = FILTEROP_ISFD, .f_attach = NULL, .f_detach = filt_deaddetach, .f_event = filt_badfd, }; void kqpoll_init(void) { struct proc *p = curproc; struct filedesc *fdp; if (p->p_kq != NULL) { /* * Discard any knotes that have been enqueued after * previous scan. * This prevents accumulation of enqueued badfd knotes * in case scan does not make progress for some reason. */ kqpoll_dequeue(p); return; } p->p_kq = kqueue_alloc(p->p_fd); p->p_kq_serial = arc4random(); fdp = p->p_fd; fdplock(fdp); LIST_INSERT_HEAD(&fdp->fd_kqlist, p->p_kq, kq_next); fdpunlock(fdp); } void kqpoll_exit(void) { struct proc *p = curproc; if (p->p_kq == NULL) return; kqueue_purge(p, p->p_kq); /* Clear any detached knotes that remain in the queue. */ kqpoll_dequeue(p); kqueue_terminate(p, p->p_kq); KASSERT(p->p_kq->kq_refs == 1); KQRELE(p->p_kq); p->p_kq = NULL; } void kqpoll_dequeue(struct proc *p) { struct knote *kn; struct kqueue *kq = p->p_kq; int s; s = splhigh(); while ((kn = TAILQ_FIRST(&kq->kq_head)) != NULL) { /* This kqueue should not be scanned by other threads. */ KASSERT(kn->kn_filter != EVFILT_MARKER); if (!knote_acquire(kn, NULL, 0)) continue; kqueue_check(kq); TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); kn->kn_status &= ~KN_QUEUED; kq->kq_count--; splx(s); kn->kn_fop->f_detach(kn); knote_drop(kn, p); s = splhigh(); kqueue_check(kq); } splx(s); } struct kqueue * kqueue_alloc(struct filedesc *fdp) { struct kqueue *kq; kq = pool_get(&kqueue_pool, PR_WAITOK | PR_ZERO); kq->kq_refs = 1; kq->kq_fdp = fdp; TAILQ_INIT(&kq->kq_head); task_set(&kq->kq_task, kqueue_task, kq); return (kq); } int sys_kqueue(struct proc *p, void *v, register_t *retval) { struct filedesc *fdp = p->p_fd; struct kqueue *kq; struct file *fp; int fd, error; kq = kqueue_alloc(fdp); fdplock(fdp); error = falloc(p, &fp, &fd); if (error) goto out; fp->f_flag = FREAD | FWRITE; fp->f_type = DTYPE_KQUEUE; fp->f_ops = &kqueueops; fp->f_data = kq; *retval = fd; LIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_next); kq = NULL; fdinsert(fdp, fd, 0, fp); FRELE(fp, p); out: fdpunlock(fdp); if (kq != NULL) pool_put(&kqueue_pool, kq); return (error); } int sys_kevent(struct proc *p, void *v, register_t *retval) { struct kqueue_scan_state scan; struct filedesc* fdp = p->p_fd; struct sys_kevent_args /* { syscallarg(int) fd; syscallarg(const struct kevent *) changelist; syscallarg(int) nchanges; syscallarg(struct kevent *) eventlist; syscallarg(int) nevents; syscallarg(const struct timespec *) timeout; } */ *uap = v; struct kevent *kevp; struct kqueue *kq; struct file *fp; struct timespec ts; struct timespec *tsp = NULL; int i, n, nerrors, error; int ready, total; struct kevent kev[KQ_NEVENTS]; if ((fp = fd_getfile(fdp, SCARG(uap, fd))) == NULL) return (EBADF); if (fp->f_type != DTYPE_KQUEUE) { error = EBADF; goto done; } if (SCARG(uap, timeout) != NULL) { error = copyin(SCARG(uap, timeout), &ts, sizeof(ts)); if (error) goto done; #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) ktrreltimespec(p, &ts); #endif if (ts.tv_sec < 0 || !timespecisvalid(&ts)) { error = EINVAL; goto done; } tsp = &ts; } kq = fp->f_data; nerrors = 0; while ((n = SCARG(uap, nchanges)) > 0) { if (n > nitems(kev)) n = nitems(kev); error = copyin(SCARG(uap, changelist), kev, n * sizeof(struct kevent)); if (error) goto done; #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) ktrevent(p, kev, n); #endif for (i = 0; i < n; i++) { kevp = &kev[i]; kevp->flags &= ~EV_SYSFLAGS; error = kqueue_register(kq, kevp, p); if (error || (kevp->flags & EV_RECEIPT)) { if (SCARG(uap, nevents) != 0) { kevp->flags = EV_ERROR; kevp->data = error; copyout(kevp, SCARG(uap, eventlist), sizeof(*kevp)); SCARG(uap, eventlist)++; SCARG(uap, nevents)--; nerrors++; } else { goto done; } } } SCARG(uap, nchanges) -= n; SCARG(uap, changelist) += n; } if (nerrors) { *retval = nerrors; error = 0; goto done; } kqueue_scan_setup(&scan, kq); FRELE(fp, p); /* * Collect as many events as we can. The timeout on successive * loops is disabled (kqueue_scan() becomes non-blocking). */ total = 0; error = 0; while ((n = SCARG(uap, nevents) - total) > 0) { if (n > nitems(kev)) n = nitems(kev); ready = kqueue_scan(&scan, n, kev, tsp, p, &error); if (ready == 0) break; error = copyout(kev, SCARG(uap, eventlist) + total, sizeof(struct kevent) * ready); #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) ktrevent(p, kev, ready); #endif total += ready; if (error || ready < n) break; } kqueue_scan_finish(&scan); *retval = total; return (error); done: FRELE(fp, p); return (error); } #ifdef KQUEUE_DEBUG void kqueue_do_check(struct kqueue *kq, const char *func, int line) { struct knote *kn; int count = 0, nmarker = 0; KERNEL_ASSERT_LOCKED(); splassert(IPL_HIGH); TAILQ_FOREACH(kn, &kq->kq_head, kn_tqe) { if (kn->kn_filter == EVFILT_MARKER) { if ((kn->kn_status & KN_QUEUED) != 0) panic("%s:%d: kq=%p kn=%p marker QUEUED", func, line, kq, kn); nmarker++; } else { if ((kn->kn_status & KN_ACTIVE) == 0) panic("%s:%d: kq=%p kn=%p knote !ACTIVE", func, line, kq, kn); if ((kn->kn_status & KN_QUEUED) == 0) panic("%s:%d: kq=%p kn=%p knote !QUEUED", func, line, kq, kn); if (kn->kn_kq != kq) panic("%s:%d: kq=%p kn=%p kn_kq=%p != kq", func, line, kq, kn, kn->kn_kq); count++; if (count > kq->kq_count) goto bad; } } if (count != kq->kq_count) { bad: panic("%s:%d: kq=%p kq_count=%d count=%d nmarker=%d", func, line, kq, kq->kq_count, count, nmarker); } } #endif int kqueue_register(struct kqueue *kq, struct kevent *kev, struct proc *p) { struct filedesc *fdp = kq->kq_fdp; const struct filterops *fops = NULL; struct file *fp = NULL; struct knote *kn = NULL, *newkn = NULL; struct knlist *list = NULL; int s, error = 0; if (kev->filter < 0) { if (kev->filter + EVFILT_SYSCOUNT < 0) return (EINVAL); fops = sysfilt_ops[~kev->filter]; /* to 0-base index */ } if (fops == NULL) { /* * XXX * filter attach routine is responsible for ensuring that * the identifier can be attached to it. */ return (EINVAL); } if (fops->f_flags & FILTEROP_ISFD) { /* validate descriptor */ if (kev->ident > INT_MAX) return (EBADF); } if (kev->flags & EV_ADD) newkn = pool_get(&knote_pool, PR_WAITOK | PR_ZERO); again: if (fops->f_flags & FILTEROP_ISFD) { if ((fp = fd_getfile(fdp, kev->ident)) == NULL) { error = EBADF; goto done; } if (kev->flags & EV_ADD) kqueue_expand_list(kq, kev->ident); if (kev->ident < kq->kq_knlistsize) list = &kq->kq_knlist[kev->ident]; } else { if (kev->flags & EV_ADD) kqueue_expand_hash(kq); if (kq->kq_knhashmask != 0) { list = &kq->kq_knhash[ KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; } } if (list != NULL) { SLIST_FOREACH(kn, list, kn_link) { if (kev->filter == kn->kn_filter && kev->ident == kn->kn_id) { s = splhigh(); if (!knote_acquire(kn, NULL, 0)) { splx(s); if (fp != NULL) { FRELE(fp, p); fp = NULL; } goto again; } splx(s); break; } } } KASSERT(kn == NULL || (kn->kn_status & KN_PROCESSING) != 0); if (kn == NULL && ((kev->flags & EV_ADD) == 0)) { error = ENOENT; goto done; } /* * kn now contains the matching knote, or NULL if no match. * If adding a new knote, sleeping is not allowed until the knote * has been inserted. */ if (kev->flags & EV_ADD) { if (kn == NULL) { kn = newkn; newkn = NULL; kn->kn_status = KN_PROCESSING; kn->kn_fp = fp; kn->kn_kq = kq; kn->kn_fop = fops; /* * apply reference count to knote structure, and * do not release it at the end of this routine. */ fp = NULL; kn->kn_sfflags = kev->fflags; kn->kn_sdata = kev->data; kev->fflags = 0; kev->data = 0; kn->kn_kevent = *kev; knote_attach(kn); if ((error = fops->f_attach(kn)) != 0) { knote_drop(kn, p); goto done; } /* * If this is a file descriptor filter, check if * fd was closed while the knote was being added. * knote_fdclose() has missed kn if the function * ran before kn appeared in kq_knlist. */ if ((fops->f_flags & FILTEROP_ISFD) && fd_checkclosed(fdp, kev->ident, kn->kn_fp)) { /* * Drop the knote silently without error * because another thread might already have * seen it. This corresponds to the insert * happening in full before the close. */ kn->kn_fop->f_detach(kn); knote_drop(kn, p); goto done; } } else { /* * The user may change some filter values after the * initial EV_ADD, but doing so will not reset any * filters which have already been triggered. */ kn->kn_sfflags = kev->fflags; kn->kn_sdata = kev->data; kn->kn_kevent.udata = kev->udata; } s = splhigh(); if (kn->kn_fop->f_event(kn, 0)) knote_activate(kn); splx(s); } else if (kev->flags & EV_DELETE) { kn->kn_fop->f_detach(kn); knote_drop(kn, p); goto done; } if ((kev->flags & EV_DISABLE) && ((kn->kn_status & KN_DISABLED) == 0)) { s = splhigh(); kn->kn_status |= KN_DISABLED; splx(s); } if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { s = splhigh(); kn->kn_status &= ~KN_DISABLED; if (kn->kn_fop->f_event(kn, 0)) kn->kn_status |= KN_ACTIVE; if ((kn->kn_status & KN_ACTIVE) && ((kn->kn_status & KN_QUEUED) == 0)) knote_enqueue(kn); splx(s); } s = splhigh(); knote_release(kn); splx(s); done: if (fp != NULL) FRELE(fp, p); if (newkn != NULL) pool_put(&knote_pool, newkn); return (error); } int kqueue_sleep(struct kqueue *kq, struct timespec *tsp) { struct timespec elapsed, start, stop; uint64_t nsecs; int error; splassert(IPL_HIGH); if (tsp != NULL) { getnanouptime(&start); nsecs = MIN(TIMESPEC_TO_NSEC(tsp), MAXTSLP); } else nsecs = INFSLP; error = tsleep_nsec(kq, PSOCK | PCATCH, "kqread", nsecs); if (tsp != NULL) { getnanouptime(&stop); timespecsub(&stop, &start, &elapsed); timespecsub(tsp, &elapsed, tsp); if (tsp->tv_sec < 0) timespecclear(tsp); } return (error); } /* * Scan the kqueue, blocking if 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. */ int kqueue_scan(struct kqueue_scan_state *scan, int maxevents, struct kevent *kevp, struct timespec *tsp, struct proc *p, int *errorp) { struct kqueue *kq = scan->kqs_kq; struct knote *kn; int s, error = 0, nkev = 0; if (maxevents == 0) goto done; retry: KASSERT(nkev == 0); error = 0; if (kq->kq_state & KQ_DYING) { error = EBADF; goto done; } s = splhigh(); if (kq->kq_count == 0) { /* * Successive loops are only necessary if there are more * ready events to gather, so they don't need to block. */ if ((tsp != NULL && !timespecisset(tsp)) || scan->kqs_nevent != 0) { splx(s); error = 0; goto done; } kq->kq_state |= KQ_SLEEP; error = kqueue_sleep(kq, tsp); splx(s); if (error == 0 || error == EWOULDBLOCK) goto retry; /* don't restart after signals... */ if (error == ERESTART) error = EINTR; goto done; } /* * Put the end marker in the queue to limit the scan to the events * that are currently active. This prevents events from being * recollected if they reactivate during scan. * * If a partial scan has been performed already but no events have * been collected, reposition the end marker to make any new events * reachable. */ if (!scan->kqs_queued) { TAILQ_INSERT_TAIL(&kq->kq_head, &scan->kqs_end, kn_tqe); scan->kqs_queued = 1; } else if (scan->kqs_nevent == 0) { TAILQ_REMOVE(&kq->kq_head, &scan->kqs_end, kn_tqe); TAILQ_INSERT_TAIL(&kq->kq_head, &scan->kqs_end, kn_tqe); } TAILQ_INSERT_HEAD(&kq->kq_head, &scan->kqs_start, kn_tqe); while (nkev < maxevents) { kn = TAILQ_NEXT(&scan->kqs_start, kn_tqe); if (kn->kn_filter == EVFILT_MARKER) { if (kn == &scan->kqs_end) break; /* Move start marker past another thread's marker. */ TAILQ_REMOVE(&kq->kq_head, &scan->kqs_start, kn_tqe); TAILQ_INSERT_AFTER(&kq->kq_head, kn, &scan->kqs_start, kn_tqe); continue; } if (!knote_acquire(kn, NULL, 0)) continue; kqueue_check(kq); TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); kn->kn_status &= ~KN_QUEUED; kq->kq_count--; kqueue_check(kq); if (kn->kn_status & KN_DISABLED) { knote_release(kn); continue; } if ((kn->kn_flags & EV_ONESHOT) == 0 && kn->kn_fop->f_event(kn, 0) == 0) { if ((kn->kn_status & KN_QUEUED) == 0) kn->kn_status &= ~KN_ACTIVE; knote_release(kn); kqueue_check(kq); continue; } *kevp = kn->kn_kevent; kevp++; nkev++; scan->kqs_nevent++; /* * Post-event action on the note */ if (kn->kn_flags & EV_ONESHOT) { splx(s); kn->kn_fop->f_detach(kn); knote_drop(kn, p); s = splhigh(); } else if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { if (kn->kn_flags & EV_CLEAR) { kn->kn_data = 0; kn->kn_fflags = 0; } if (kn->kn_flags & EV_DISPATCH) kn->kn_status |= KN_DISABLED; if ((kn->kn_status & KN_QUEUED) == 0) kn->kn_status &= ~KN_ACTIVE; KASSERT(kn->kn_status & KN_ATTACHED); knote_release(kn); } else { if ((kn->kn_status & KN_QUEUED) == 0) { kqueue_check(kq); kq->kq_count++; kn->kn_status |= KN_QUEUED; TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); } KASSERT(kn->kn_status & KN_ATTACHED); knote_release(kn); } kqueue_check(kq); } TAILQ_REMOVE(&kq->kq_head, &scan->kqs_start, kn_tqe); splx(s); if (scan->kqs_nevent == 0) goto retry; done: *errorp = error; return (nkev); } void kqueue_scan_setup(struct kqueue_scan_state *scan, struct kqueue *kq) { memset(scan, 0, sizeof(*scan)); KQREF(kq); scan->kqs_kq = kq; scan->kqs_start.kn_filter = EVFILT_MARKER; scan->kqs_start.kn_status = KN_PROCESSING; scan->kqs_end.kn_filter = EVFILT_MARKER; scan->kqs_end.kn_status = KN_PROCESSING; } void kqueue_scan_finish(struct kqueue_scan_state *scan) { struct kqueue *kq = scan->kqs_kq; int s; KASSERT(scan->kqs_start.kn_filter == EVFILT_MARKER); KASSERT(scan->kqs_start.kn_status == KN_PROCESSING); KASSERT(scan->kqs_end.kn_filter == EVFILT_MARKER); KASSERT(scan->kqs_end.kn_status == KN_PROCESSING); if (scan->kqs_queued) { scan->kqs_queued = 0; s = splhigh(); TAILQ_REMOVE(&kq->kq_head, &scan->kqs_end, kn_tqe); splx(s); } KQRELE(kq); } /* * XXX * This could be expanded to call kqueue_scan, if desired. */ int kqueue_read(struct file *fp, struct uio *uio, int fflags) { return (ENXIO); } int kqueue_write(struct file *fp, struct uio *uio, int fflags) { return (ENXIO); } int kqueue_ioctl(struct file *fp, u_long com, caddr_t data, struct proc *p) { return (ENOTTY); } int kqueue_poll(struct file *fp, int events, struct proc *p) { struct kqueue *kq = (struct kqueue *)fp->f_data; int revents = 0; int s = splhigh(); if (events & (POLLIN | POLLRDNORM)) { if (kq->kq_count) { revents |= events & (POLLIN | POLLRDNORM); } else { selrecord(p, &kq->kq_sel); kq->kq_state |= KQ_SEL; } } splx(s); return (revents); } int kqueue_stat(struct file *fp, struct stat *st, struct proc *p) { struct kqueue *kq = fp->f_data; memset(st, 0, sizeof(*st)); st->st_size = kq->kq_count; st->st_blksize = sizeof(struct kevent); st->st_mode = S_IFIFO; return (0); } void kqueue_purge(struct proc *p, struct kqueue *kq) { int i; KERNEL_ASSERT_LOCKED(); for (i = 0; i < kq->kq_knlistsize; i++) knote_remove(p, &kq->kq_knlist[i], 1); if (kq->kq_knhashmask != 0) { for (i = 0; i < kq->kq_knhashmask + 1; i++) knote_remove(p, &kq->kq_knhash[i], 1); } } void kqueue_terminate(struct proc *p, struct kqueue *kq) { struct knote *kn; /* * Any remaining entries should be scan markers. * They are removed when the ongoing scans finish. */ KASSERT(kq->kq_count == 0); TAILQ_FOREACH(kn, &kq->kq_head, kn_tqe) KASSERT(kn->kn_filter == EVFILT_MARKER); kq->kq_state |= KQ_DYING; kqueue_wakeup(kq); KASSERT(klist_empty(&kq->kq_sel.si_note)); task_del(systq, &kq->kq_task); } int kqueue_close(struct file *fp, struct proc *p) { struct kqueue *kq = fp->f_data; KERNEL_LOCK(); kqueue_purge(p, kq); kqueue_terminate(p, kq); fp->f_data = NULL; KQRELE(kq); KERNEL_UNLOCK(); return (0); } static void kqueue_task(void *arg) { struct kqueue *kq = arg; if (kq->kq_state & KQ_SEL) { kq->kq_state &= ~KQ_SEL; selwakeup(&kq->kq_sel); } else { KNOTE(&kq->kq_sel.si_note, 0); } KQRELE(kq); } void kqueue_wakeup(struct kqueue *kq) { if (kq->kq_state & KQ_SLEEP) { kq->kq_state &= ~KQ_SLEEP; wakeup(kq); } if ((kq->kq_state & KQ_SEL) || !klist_empty(&kq->kq_sel.si_note)) { /* Defer activation to avoid recursion. */ KQREF(kq); if (!task_add(systq, &kq->kq_task)) KQRELE(kq); } } static void kqueue_expand_hash(struct kqueue *kq) { struct knlist *hash; u_long hashmask; if (kq->kq_knhashmask == 0) { hash = hashinit(KN_HASHSIZE, M_KEVENT, M_WAITOK, &hashmask); if (kq->kq_knhashmask == 0) { kq->kq_knhash = hash; kq->kq_knhashmask = hashmask; } else { /* Another thread has allocated the hash. */ hashfree(hash, KN_HASHSIZE, M_KEVENT); } } } static void kqueue_expand_list(struct kqueue *kq, int fd) { struct knlist *list; int size; if (kq->kq_knlistsize <= fd) { size = kq->kq_knlistsize; while (size <= fd) size += KQEXTENT; list = mallocarray(size, sizeof(*list), M_KEVENT, M_WAITOK); if (kq->kq_knlistsize <= fd) { memcpy(list, kq->kq_knlist, kq->kq_knlistsize * sizeof(*list)); memset(&list[kq->kq_knlistsize], 0, (size - kq->kq_knlistsize) * sizeof(*list)); free(kq->kq_knlist, M_KEVENT, kq->kq_knlistsize * sizeof(*list)); kq->kq_knlist = list; kq->kq_knlistsize = size; } else { /* Another thread has expanded the list. */ free(list, M_KEVENT, size * sizeof(*list)); } } } /* * 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. * * If we are about to sleep and klist is non-NULL, the list is unlocked * before sleep and remains unlocked on return. */ int knote_acquire(struct knote *kn, struct klist *klist, int ls) { splassert(IPL_HIGH); KASSERT(kn->kn_filter != EVFILT_MARKER); if (kn->kn_status & KN_PROCESSING) { kn->kn_status |= KN_WAITING; if (klist != NULL) klist_unlock(klist, ls); tsleep_nsec(kn, 0, "kqepts", SEC_TO_NSEC(1)); /* knote may be stale now */ return (0); } kn->kn_status |= KN_PROCESSING; return (1); } /* * Release an acquired knote, clearing KN_PROCESSING. */ void knote_release(struct knote *kn) { splassert(IPL_HIGH); KASSERT(kn->kn_filter != EVFILT_MARKER); KASSERT(kn->kn_status & KN_PROCESSING); if (kn->kn_status & KN_WAITING) { kn->kn_status &= ~KN_WAITING; wakeup(kn); } kn->kn_status &= ~KN_PROCESSING; /* kn should not be accessed anymore */ } /* * activate one knote. */ void knote_activate(struct knote *kn) { int s; s = splhigh(); kn->kn_status |= KN_ACTIVE; if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) knote_enqueue(kn); splx(s); } /* * walk down a list of knotes, activating them if their event has triggered. */ void knote(struct klist *list, long hint) { struct knote *kn, *kn0; KLIST_ASSERT_LOCKED(list); SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, kn0) if (kn->kn_fop->f_event(kn, hint)) knote_activate(kn); } /* * remove all knotes from a specified knlist */ void knote_remove(struct proc *p, struct knlist *list, int purge) { struct knote *kn; int s; while ((kn = SLIST_FIRST(list)) != NULL) { s = splhigh(); if (!knote_acquire(kn, NULL, 0)) { splx(s); continue; } splx(s); kn->kn_fop->f_detach(kn); /* * Notify poll(2) and select(2) when a monitored * file descriptor is closed. * * This reuses the original knote for delivering the * notification so as to avoid allocating memory. * The knote will be reachable only through the queue * of active knotes and is freed either by kqueue_scan() * or kqpoll_dequeue(). */ if (!purge && (kn->kn_flags & __EV_POLL) != 0) { KASSERT(kn->kn_fop->f_flags & FILTEROP_ISFD); knote_detach(kn); FRELE(kn->kn_fp, p); kn->kn_fp = NULL; kn->kn_fop = &badfd_filtops; kn->kn_fop->f_event(kn, 0); knote_activate(kn); s = splhigh(); knote_release(kn); splx(s); continue; } knote_drop(kn, p); } } /* * remove all knotes referencing a specified fd */ void knote_fdclose(struct proc *p, int fd) { struct filedesc *fdp = p->p_p->ps_fd; struct kqueue *kq; struct knlist *list; /* * fdplock can be ignored if the file descriptor table is being freed * because no other thread can access the fdp. */ if (fdp->fd_refcnt != 0) fdpassertlocked(fdp); if (LIST_EMPTY(&fdp->fd_kqlist)) return; KERNEL_LOCK(); LIST_FOREACH(kq, &fdp->fd_kqlist, kq_next) { if (fd >= kq->kq_knlistsize) continue; list = &kq->kq_knlist[fd]; knote_remove(p, list, 0); } KERNEL_UNLOCK(); } /* * handle a process exiting, including the triggering of NOTE_EXIT notes * XXX this could be more efficient, doing a single pass down the klist */ void knote_processexit(struct proc *p) { struct process *pr = p->p_p; KASSERT(p == curproc); KNOTE(&pr->ps_klist, NOTE_EXIT); /* remove other knotes hanging off the process */ klist_invalidate(&pr->ps_klist); } void knote_attach(struct knote *kn) { struct kqueue *kq = kn->kn_kq; struct knlist *list; int s; KASSERT(kn->kn_status & KN_PROCESSING); KASSERT((kn->kn_status & KN_ATTACHED) == 0); s = splhigh(); kn->kn_status |= KN_ATTACHED; splx(s); if (kn->kn_fop->f_flags & FILTEROP_ISFD) { KASSERT(kq->kq_knlistsize > kn->kn_id); list = &kq->kq_knlist[kn->kn_id]; } else { KASSERT(kq->kq_knhashmask != 0); list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; } SLIST_INSERT_HEAD(list, kn, kn_link); } void knote_detach(struct knote *kn) { struct kqueue *kq = kn->kn_kq; struct knlist *list; int s; KASSERT(kn->kn_status & KN_PROCESSING); if ((kn->kn_status & KN_ATTACHED) == 0) return; if (kn->kn_fop->f_flags & FILTEROP_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); s = splhigh(); kn->kn_status &= ~KN_ATTACHED; splx(s); } /* * should be called at spl == 0, since we don't want to hold spl * while calling FRELE and pool_put. */ void knote_drop(struct knote *kn, struct proc *p) { int s; KASSERT(kn->kn_filter != EVFILT_MARKER); knote_detach(kn); s = splhigh(); if (kn->kn_status & KN_QUEUED) knote_dequeue(kn); if (kn->kn_status & KN_WAITING) { kn->kn_status &= ~KN_WAITING; wakeup(kn); } splx(s); if ((kn->kn_fop->f_flags & FILTEROP_ISFD) && kn->kn_fp != NULL) FRELE(kn->kn_fp, p); pool_put(&knote_pool, kn); } void knote_enqueue(struct knote *kn) { struct kqueue *kq = kn->kn_kq; splassert(IPL_HIGH); KASSERT(kn->kn_filter != EVFILT_MARKER); KASSERT((kn->kn_status & KN_QUEUED) == 0); kqueue_check(kq); TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); kn->kn_status |= KN_QUEUED; kq->kq_count++; kqueue_check(kq); kqueue_wakeup(kq); } void knote_dequeue(struct knote *kn) { struct kqueue *kq = kn->kn_kq; splassert(IPL_HIGH); KASSERT(kn->kn_filter != EVFILT_MARKER); KASSERT(kn->kn_status & KN_QUEUED); kqueue_check(kq); TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); kn->kn_status &= ~KN_QUEUED; kq->kq_count--; kqueue_check(kq); } void klist_init(struct klist *klist, const struct klistops *ops, void *arg) { SLIST_INIT(&klist->kl_list); klist->kl_ops = ops; klist->kl_arg = arg; } void klist_free(struct klist *klist) { KASSERT(SLIST_EMPTY(&klist->kl_list)); } void klist_insert(struct klist *klist, struct knote *kn) { int ls; ls = klist_lock(klist); SLIST_INSERT_HEAD(&klist->kl_list, kn, kn_selnext); klist_unlock(klist, ls); } void klist_insert_locked(struct klist *klist, struct knote *kn) { KLIST_ASSERT_LOCKED(klist); SLIST_INSERT_HEAD(&klist->kl_list, kn, kn_selnext); } void klist_remove(struct klist *klist, struct knote *kn) { int ls; ls = klist_lock(klist); SLIST_REMOVE(&klist->kl_list, kn, knote, kn_selnext); klist_unlock(klist, ls); } void klist_remove_locked(struct klist *klist, struct knote *kn) { KLIST_ASSERT_LOCKED(klist); SLIST_REMOVE(&klist->kl_list, kn, knote, kn_selnext); } int klist_empty(struct klist *klist) { return (SLIST_EMPTY(&klist->kl_list)); } /* * Detach all knotes from klist. The knotes are rewired to indicate EOF. * * The caller of this function must not hold any locks that can block * filterops callbacks that run with KN_PROCESSING. * Otherwise this function might deadlock. */ void klist_invalidate(struct klist *list) { struct knote *kn; struct proc *p = curproc; int ls, s; NET_ASSERT_UNLOCKED(); s = splhigh(); ls = klist_lock(list); while ((kn = SLIST_FIRST(&list->kl_list)) != NULL) { if (!knote_acquire(kn, list, ls)) { /* knote_acquire() has unlocked list. */ ls = klist_lock(list); continue; } klist_unlock(list, ls); splx(s); kn->kn_fop->f_detach(kn); if (kn->kn_fop->f_flags & FILTEROP_ISFD) { kn->kn_fop = &dead_filtops; kn->kn_fop->f_event(kn, 0); knote_activate(kn); s = splhigh(); knote_release(kn); } else { knote_drop(kn, p); s = splhigh(); } ls = klist_lock(list); } klist_unlock(list, ls); splx(s); } static int klist_lock(struct klist *list) { int ls = 0; if (list->kl_ops != NULL) { ls = list->kl_ops->klo_lock(list->kl_arg); } else { KERNEL_LOCK(); ls = splhigh(); } return ls; } static void klist_unlock(struct klist *list, int ls) { if (list->kl_ops != NULL) { list->kl_ops->klo_unlock(list->kl_arg, ls); } else { splx(ls); KERNEL_UNLOCK(); } } static void klist_mutex_assertlk(void *arg) { struct mutex *mtx = arg; (void)mtx; MUTEX_ASSERT_LOCKED(mtx); } static int klist_mutex_lock(void *arg) { struct mutex *mtx = arg; mtx_enter(mtx); return 0; } static void klist_mutex_unlock(void *arg, int s) { struct mutex *mtx = arg; mtx_leave(mtx); } static const struct klistops mutex_klistops = { .klo_assertlk = klist_mutex_assertlk, .klo_lock = klist_mutex_lock, .klo_unlock = klist_mutex_unlock, }; void klist_init_mutex(struct klist *klist, struct mutex *mtx) { klist_init(klist, &mutex_klistops, mtx); } static void klist_rwlock_assertlk(void *arg) { struct rwlock *rwl = arg; (void)rwl; rw_assert_wrlock(rwl); } static int klist_rwlock_lock(void *arg) { struct rwlock *rwl = arg; rw_enter_write(rwl); return 0; } static void klist_rwlock_unlock(void *arg, int s) { struct rwlock *rwl = arg; rw_exit_write(rwl); } static const struct klistops rwlock_klistops = { .klo_assertlk = klist_rwlock_assertlk, .klo_lock = klist_rwlock_lock, .klo_unlock = klist_rwlock_unlock, }; void klist_init_rwlock(struct klist *klist, struct rwlock *rwl) { klist_init(klist, &rwlock_klistops, rwl); }