/* $NetBSD: kern_event.c,v 1.59 2008/05/05 17:11:17 ad Exp $ */ /*- * Copyright (c) 2008 The NetBSD Foundation, Inc. * 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /*- * Copyright (c) 1999,2000,2001 Jonathan Lemon * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * FreeBSD: src/sys/kern/kern_event.c,v 1.27 2001/07/05 17:10:44 rwatson Exp */ #include __KERNEL_RCSID(0, "$NetBSD: kern_event.c,v 1.59 2008/05/05 17:11:17 ad Exp $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static int kqueue_scan(file_t *, size_t, struct kevent *, const struct timespec *, register_t *, const struct kevent_ops *, struct kevent *, size_t); static int kqueue_ioctl(file_t *, u_long, void *); static int kqueue_fcntl(file_t *, u_int, void *); static int kqueue_poll(file_t *, int); static int kqueue_kqfilter(file_t *, struct knote *); static int kqueue_stat(file_t *, struct stat *); static int kqueue_close(file_t *); static int kqueue_register(struct kqueue *, struct kevent *); static void kqueue_doclose(struct kqueue *, struct klist *, int); static void knote_detach(struct knote *, filedesc_t *fdp, bool); static void knote_enqueue(struct knote *); static void knote_activate(struct knote *); static void filt_kqdetach(struct knote *); static int filt_kqueue(struct knote *, long hint); static int filt_procattach(struct knote *); static void filt_procdetach(struct knote *); static int filt_proc(struct knote *, long hint); static int filt_fileattach(struct knote *); static void filt_timerexpire(void *x); static int filt_timerattach(struct knote *); static void filt_timerdetach(struct knote *); static int filt_timer(struct knote *, long hint); static const struct fileops kqueueops = { (void *)enxio, (void *)enxio, kqueue_ioctl, kqueue_fcntl, kqueue_poll, kqueue_stat, kqueue_close, kqueue_kqfilter }; static const struct filterops kqread_filtops = { 1, NULL, filt_kqdetach, filt_kqueue }; static const struct filterops proc_filtops = { 0, filt_procattach, filt_procdetach, filt_proc }; static const struct filterops file_filtops = { 1, filt_fileattach, NULL, NULL }; static const struct filterops timer_filtops = { 0, filt_timerattach, filt_timerdetach, filt_timer }; static u_int kq_ncallouts = 0; static int kq_calloutmax = (4 * 1024); #define KN_HASHSIZE 64 /* XXX should be tunable */ #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) extern const struct filterops sig_filtops; /* * Table for for all system-defined filters. * These should be listed in the numeric order of the EVFILT_* defines. * If filtops is NULL, the filter isn't implemented in NetBSD. * End of list is when name is NULL. * * Note that 'refcnt' is meaningless for built-in filters. */ struct kfilter { const char *name; /* name of filter */ uint32_t filter; /* id of filter */ unsigned refcnt; /* reference count */ const struct filterops *filtops;/* operations for filter */ size_t namelen; /* length of name string */ }; /* System defined filters */ static struct kfilter sys_kfilters[] = { { "EVFILT_READ", EVFILT_READ, 0, &file_filtops, 0 }, { "EVFILT_WRITE", EVFILT_WRITE, 0, &file_filtops, 0, }, { "EVFILT_AIO", EVFILT_AIO, 0, NULL, 0 }, { "EVFILT_VNODE", EVFILT_VNODE, 0, &file_filtops, 0 }, { "EVFILT_PROC", EVFILT_PROC, 0, &proc_filtops, 0 }, { "EVFILT_SIGNAL", EVFILT_SIGNAL, 0, &sig_filtops, 0 }, { "EVFILT_TIMER", EVFILT_TIMER, 0, &timer_filtops, 0 }, { NULL, 0, 0, NULL, 0 }, }; /* User defined kfilters */ static struct kfilter *user_kfilters; /* array */ static int user_kfilterc; /* current offset */ static int user_kfiltermaxc; /* max size so far */ static size_t user_kfiltersz; /* size of allocated memory */ /* Locks */ static krwlock_t kqueue_filter_lock; /* lock on filter lists */ static kmutex_t kqueue_misc_lock; /* miscellaneous */ /* * Initialize the kqueue subsystem. */ void kqueue_init(void) { rw_init(&kqueue_filter_lock); mutex_init(&kqueue_misc_lock, MUTEX_DEFAULT, IPL_NONE); } /* * Find kfilter entry by name, or NULL if not found. */ static struct kfilter * kfilter_byname_sys(const char *name) { int i; KASSERT(rw_lock_held(&kqueue_filter_lock)); for (i = 0; sys_kfilters[i].name != NULL; i++) { if (strcmp(name, sys_kfilters[i].name) == 0) return &sys_kfilters[i]; } return NULL; } static struct kfilter * kfilter_byname_user(const char *name) { int i; KASSERT(rw_lock_held(&kqueue_filter_lock)); /* user filter slots have a NULL name if previously deregistered */ for (i = 0; i < user_kfilterc ; i++) { if (user_kfilters[i].name != NULL && strcmp(name, user_kfilters[i].name) == 0) return &user_kfilters[i]; } return NULL; } static struct kfilter * kfilter_byname(const char *name) { struct kfilter *kfilter; KASSERT(rw_lock_held(&kqueue_filter_lock)); if ((kfilter = kfilter_byname_sys(name)) != NULL) return kfilter; return kfilter_byname_user(name); } /* * Find kfilter entry by filter id, or NULL if not found. * Assumes entries are indexed in filter id order, for speed. */ static struct kfilter * kfilter_byfilter(uint32_t filter) { struct kfilter *kfilter; KASSERT(rw_lock_held(&kqueue_filter_lock)); if (filter < EVFILT_SYSCOUNT) /* it's a system filter */ kfilter = &sys_kfilters[filter]; else if (user_kfilters != NULL && filter < EVFILT_SYSCOUNT + user_kfilterc) /* it's a user filter */ kfilter = &user_kfilters[filter - EVFILT_SYSCOUNT]; else return (NULL); /* out of range */ KASSERT(kfilter->filter == filter); /* sanity check! */ return (kfilter); } /* * Register a new kfilter. Stores the entry in user_kfilters. * Returns 0 if operation succeeded, or an appropriate errno(2) otherwise. * If retfilter != NULL, the new filterid is returned in it. */ int kfilter_register(const char *name, const struct filterops *filtops, int *retfilter) { struct kfilter *kfilter; size_t len; int i; if (name == NULL || name[0] == '\0' || filtops == NULL) return (EINVAL); /* invalid args */ rw_enter(&kqueue_filter_lock, RW_WRITER); if (kfilter_byname(name) != NULL) { rw_exit(&kqueue_filter_lock); return (EEXIST); /* already exists */ } if (user_kfilterc > 0xffffffff - EVFILT_SYSCOUNT) { rw_exit(&kqueue_filter_lock); return (EINVAL); /* too many */ } for (i = 0; i < user_kfilterc; i++) { kfilter = &user_kfilters[i]; if (kfilter->name == NULL) { /* Previously deregistered slot. Reuse. */ goto reuse; } } /* check if need to grow user_kfilters */ if (user_kfilterc + 1 > user_kfiltermaxc) { /* Grow in KFILTER_EXTENT chunks. */ user_kfiltermaxc += KFILTER_EXTENT; len = user_kfiltermaxc * sizeof(struct filter *); kfilter = kmem_alloc(len, KM_SLEEP); memset((char *)kfilter + user_kfiltersz, 0, len - user_kfiltersz); if (user_kfilters != NULL) { memcpy(kfilter, user_kfilters, user_kfiltersz); kmem_free(user_kfilters, user_kfiltersz); } user_kfiltersz = len; user_kfilters = kfilter; } /* Adding new slot */ kfilter = &user_kfilters[user_kfilterc++]; reuse: kfilter->namelen = strlen(name) + 1; kfilter->name = kmem_alloc(kfilter->namelen, KM_SLEEP); memcpy(__UNCONST(kfilter->name), name, kfilter->namelen); kfilter->filter = (kfilter - user_kfilters) + EVFILT_SYSCOUNT; kfilter->filtops = kmem_alloc(sizeof(*filtops), KM_SLEEP); memcpy(__UNCONST(kfilter->filtops), filtops, sizeof(*filtops)); if (retfilter != NULL) *retfilter = kfilter->filter; rw_exit(&kqueue_filter_lock); return (0); } /* * Unregister a kfilter previously registered with kfilter_register. * This retains the filter id, but clears the name and frees filtops (filter * operations), so that the number isn't reused during a boot. * Returns 0 if operation succeeded, or an appropriate errno(2) otherwise. */ int kfilter_unregister(const char *name) { struct kfilter *kfilter; if (name == NULL || name[0] == '\0') return (EINVAL); /* invalid name */ rw_enter(&kqueue_filter_lock, RW_WRITER); if (kfilter_byname_sys(name) != NULL) { rw_exit(&kqueue_filter_lock); return (EINVAL); /* can't detach system filters */ } kfilter = kfilter_byname_user(name); if (kfilter == NULL) { rw_exit(&kqueue_filter_lock); return (ENOENT); } if (kfilter->refcnt != 0) { rw_exit(&kqueue_filter_lock); return (EBUSY); } /* Cast away const (but we know it's safe. */ kmem_free(__UNCONST(kfilter->name), kfilter->namelen); kfilter->name = NULL; /* mark as `not implemented' */ if (kfilter->filtops != NULL) { /* Cast away const (but we know it's safe. */ kmem_free(__UNCONST(kfilter->filtops), sizeof(*kfilter->filtops)); kfilter->filtops = NULL; /* mark as `not implemented' */ } rw_exit(&kqueue_filter_lock); return (0); } /* * Filter attach method for EVFILT_READ and EVFILT_WRITE on normal file * descriptors. Calls fileops kqfilter method for given file descriptor. */ static int filt_fileattach(struct knote *kn) { file_t *fp; fp = kn->kn_obj; return (*fp->f_ops->fo_kqfilter)(fp, kn); } /* * Filter detach method for EVFILT_READ on kqueue descriptor. */ static void filt_kqdetach(struct knote *kn) { struct kqueue *kq; kq = ((file_t *)kn->kn_obj)->f_data; mutex_spin_enter(&kq->kq_lock); SLIST_REMOVE(&kq->kq_sel.sel_klist, kn, knote, kn_selnext); mutex_spin_exit(&kq->kq_lock); } /* * Filter event method for EVFILT_READ on kqueue descriptor. */ /*ARGSUSED*/ static int filt_kqueue(struct knote *kn, long hint) { struct kqueue *kq; int rv; kq = ((file_t *)kn->kn_obj)->f_data; if (hint != NOTE_SUBMIT) mutex_spin_enter(&kq->kq_lock); kn->kn_data = kq->kq_count; rv = (kn->kn_data > 0); if (hint != NOTE_SUBMIT) mutex_spin_exit(&kq->kq_lock); return rv; } /* * Filter attach method for EVFILT_PROC. */ static int filt_procattach(struct knote *kn) { struct proc *p, *curp; struct lwp *curl; curl = curlwp; curp = curl->l_proc; mutex_enter(proc_lock); p = p_find(kn->kn_id, PFIND_LOCKED); if (p == NULL) { mutex_exit(proc_lock); return ESRCH; } /* * Fail if it's not owned by you, or the last exec gave us * setuid/setgid privs (unless you're root). */ mutex_enter(p->p_lock); mutex_exit(proc_lock); if (kauth_authorize_process(curl->l_cred, KAUTH_PROCESS_KEVENT_FILTER, p, NULL, NULL, NULL) != 0) { mutex_exit(p->p_lock); return EACCES; } kn->kn_obj = p; kn->kn_flags |= EV_CLEAR; /* automatically set */ /* * internal flag indicating registration done by kernel */ if (kn->kn_flags & EV_FLAG1) { kn->kn_data = kn->kn_sdata; /* ppid */ kn->kn_fflags = NOTE_CHILD; kn->kn_flags &= ~EV_FLAG1; } SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); mutex_exit(p->p_lock); return 0; } /* * Filter detach method for EVFILT_PROC. * * The knote may be attached to a different process, which may exit, * leaving nothing for the knote to be attached to. So when the process * exits, the knote is marked as DETACHED and also flagged as ONESHOT so * it will be deleted when read out. However, as part of the knote deletion, * this routine is called, so a check is needed to avoid actually performing * a detach, because the original process might not exist any more. */ static void filt_procdetach(struct knote *kn) { struct proc *p; if (kn->kn_status & KN_DETACHED) return; p = kn->kn_obj; mutex_enter(p->p_lock); SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); mutex_exit(p->p_lock); } /* * Filter event method for EVFILT_PROC. */ static int filt_proc(struct knote *kn, long hint) { u_int event, fflag; struct kevent kev; struct kqueue *kq; int error; event = (u_int)hint & NOTE_PCTRLMASK; kq = kn->kn_kq; fflag = 0; /* If the user is interested in this event, record it. */ if (kn->kn_sfflags & event) fflag |= event; if (event == NOTE_EXIT) { /* * Process is gone, so flag the event as finished. * * Detach the knote from watched process and mark * it as such. We can't leave this to kqueue_scan(), * since the process might not exist by then. And we * have to do this now, since psignal KNOTE() is called * also for zombies and we might end up reading freed * memory if the kevent would already be picked up * and knote g/c'ed. */ filt_procdetach(kn); mutex_spin_enter(&kq->kq_lock); kn->kn_status |= KN_DETACHED; /* Mark as ONESHOT, so that the knote it g/c'ed when read */ kn->kn_flags |= (EV_EOF | EV_ONESHOT); kn->kn_fflags |= fflag; mutex_spin_exit(&kq->kq_lock); return 1; } mutex_spin_enter(&kq->kq_lock); if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) { /* * Process forked, and user wants to track the new process, * so attach a new knote to it, and immediately report an * event with the parent's pid. Register knote with new * process. */ kev.ident = hint & NOTE_PDATAMASK; /* pid */ kev.filter = kn->kn_filter; kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; kev.fflags = kn->kn_sfflags; kev.data = kn->kn_id; /* parent */ kev.udata = kn->kn_kevent.udata; /* preserve udata */ mutex_spin_exit(&kq->kq_lock); error = kqueue_register(kq, &kev); mutex_spin_enter(&kq->kq_lock); if (error != 0) kn->kn_fflags |= NOTE_TRACKERR; } kn->kn_fflags |= fflag; fflag = kn->kn_fflags; mutex_spin_exit(&kq->kq_lock); return fflag != 0; } static void filt_timerexpire(void *knx) { struct knote *kn = knx; int tticks; mutex_enter(&kqueue_misc_lock); kn->kn_data++; knote_activate(kn); if ((kn->kn_flags & EV_ONESHOT) == 0) { tticks = mstohz(kn->kn_sdata); callout_schedule((callout_t *)kn->kn_hook, tticks); } mutex_exit(&kqueue_misc_lock); } /* * data contains amount of time to sleep, in milliseconds */ static int filt_timerattach(struct knote *kn) { callout_t *calloutp; struct kqueue *kq; int tticks; tticks = mstohz(kn->kn_sdata); /* if the supplied value is under our resolution, use 1 tick */ if (tticks == 0) { if (kn->kn_sdata == 0) return EINVAL; tticks = 1; } if (atomic_inc_uint_nv(&kq_ncallouts) >= kq_calloutmax || (calloutp = kmem_alloc(sizeof(*calloutp), KM_NOSLEEP)) == NULL) { atomic_dec_uint(&kq_ncallouts); return ENOMEM; } callout_init(calloutp, CALLOUT_MPSAFE); kq = kn->kn_kq; mutex_spin_enter(&kq->kq_lock); kn->kn_flags |= EV_CLEAR; /* automatically set */ kn->kn_hook = calloutp; mutex_spin_exit(&kq->kq_lock); callout_reset(calloutp, tticks, filt_timerexpire, kn); return (0); } static void filt_timerdetach(struct knote *kn) { callout_t *calloutp; calloutp = (callout_t *)kn->kn_hook; callout_halt(calloutp, NULL); callout_destroy(calloutp); kmem_free(calloutp, sizeof(*calloutp)); atomic_dec_uint(&kq_ncallouts); } static int filt_timer(struct knote *kn, long hint) { int rv; mutex_enter(&kqueue_misc_lock); rv = (kn->kn_data != 0); mutex_exit(&kqueue_misc_lock); return rv; } /* * filt_seltrue: * * This filter "event" routine simulates seltrue(). */ int filt_seltrue(struct knote *kn, long hint) { /* * We don't know how much data can be read/written, * but we know that it *can* be. This is about as * good as select/poll does as well. */ kn->kn_data = 0; return (1); } /* * This provides full kqfilter entry for device switch tables, which * has same effect as filter using filt_seltrue() as filter method. */ static void filt_seltruedetach(struct knote *kn) { /* Nothing to do */ } const struct filterops seltrue_filtops = { 1, NULL, filt_seltruedetach, filt_seltrue }; int seltrue_kqfilter(dev_t dev, struct knote *kn) { switch (kn->kn_filter) { case EVFILT_READ: case EVFILT_WRITE: kn->kn_fop = &seltrue_filtops; break; default: return (EINVAL); } /* Nothing more to do */ return (0); } /* * kqueue(2) system call. */ int sys_kqueue(struct lwp *l, const void *v, register_t *retval) { struct kqueue *kq; file_t *fp; int fd, error; if ((error = fd_allocfile(&fp, &fd)) != 0) return error; fp->f_flag = FREAD | FWRITE; fp->f_type = DTYPE_KQUEUE; fp->f_ops = &kqueueops; kq = kmem_zalloc(sizeof(*kq), KM_SLEEP); mutex_init(&kq->kq_lock, MUTEX_DEFAULT, IPL_SCHED); cv_init(&kq->kq_cv, "kqueue"); selinit(&kq->kq_sel); TAILQ_INIT(&kq->kq_head); fp->f_data = kq; *retval = fd; kq->kq_fdp = curlwp->l_fd; fd_affix(curproc, fp, fd); return error; } /* * kevent(2) system call. */ static int kevent_fetch_changes(void *private, const struct kevent *changelist, struct kevent *changes, size_t index, int n) { return copyin(changelist + index, changes, n * sizeof(*changes)); } static int kevent_put_events(void *private, struct kevent *events, struct kevent *eventlist, size_t index, int n) { return copyout(events, eventlist + index, n * sizeof(*events)); } static const struct kevent_ops kevent_native_ops = { keo_private: NULL, keo_fetch_timeout: copyin, keo_fetch_changes: kevent_fetch_changes, keo_put_events: kevent_put_events, }; int sys_kevent(struct lwp *l, const struct sys_kevent_args *uap, register_t *retval) { /* { syscallarg(int) fd; syscallarg(const struct kevent *) changelist; syscallarg(size_t) nchanges; syscallarg(struct kevent *) eventlist; syscallarg(size_t) nevents; syscallarg(const struct timespec *) timeout; } */ return kevent1(retval, SCARG(uap, fd), SCARG(uap, changelist), SCARG(uap, nchanges), SCARG(uap, eventlist), SCARG(uap, nevents), SCARG(uap, timeout), &kevent_native_ops); } int kevent1(register_t *retval, int fd, const struct kevent *changelist, size_t nchanges, struct kevent *eventlist, size_t nevents, const struct timespec *timeout, const struct kevent_ops *keops) { struct kevent *kevp; struct kqueue *kq; struct timespec ts; size_t i, n, ichange; int nerrors, error; struct kevent kevbuf[8]; /* approx 300 bytes on 64-bit */ file_t *fp; /* check that we're dealing with a kq */ fp = fd_getfile(fd); if (fp == NULL) return (EBADF); if (fp->f_type != DTYPE_KQUEUE) { fd_putfile(fd); return (EBADF); } if (timeout != NULL) { error = (*keops->keo_fetch_timeout)(timeout, &ts, sizeof(ts)); if (error) goto done; timeout = &ts; } kq = (struct kqueue *)fp->f_data; nerrors = 0; ichange = 0; /* traverse list of events to register */ while (nchanges > 0) { n = MIN(nchanges, __arraycount(kevbuf)); error = (*keops->keo_fetch_changes)(keops->keo_private, changelist, kevbuf, ichange, n); if (error) goto done; for (i = 0; i < n; i++) { kevp = &kevbuf[i]; kevp->flags &= ~EV_SYSFLAGS; /* register each knote */ error = kqueue_register(kq, kevp); if (error) { if (nevents != 0) { kevp->flags = EV_ERROR; kevp->data = error; error = (*keops->keo_put_events) (keops->keo_private, kevp, eventlist, nerrors, 1); if (error) goto done; nevents--; nerrors++; } else { goto done; } } } nchanges -= n; /* update the results */ ichange += n; } if (nerrors) { *retval = nerrors; error = 0; goto done; } /* actually scan through the events */ error = kqueue_scan(fp, nevents, eventlist, timeout, retval, keops, kevbuf, __arraycount(kevbuf)); done: fd_putfile(fd); return (error); } /* * Register a given kevent kev onto the kqueue */ static int kqueue_register(struct kqueue *kq, struct kevent *kev) { struct kfilter *kfilter; filedesc_t *fdp; file_t *fp; fdfile_t *ff; struct knote *kn, *newkn; struct klist *list; int error, fd, rv; fdp = kq->kq_fdp; fp = NULL; kn = NULL; error = 0; fd = 0; newkn = kmem_zalloc(sizeof(*newkn), KM_SLEEP); rw_enter(&kqueue_filter_lock, RW_READER); kfilter = kfilter_byfilter(kev->filter); if (kfilter == NULL || kfilter->filtops == NULL) { /* filter not found nor implemented */ rw_exit(&kqueue_filter_lock); kmem_free(newkn, sizeof(*newkn)); return (EINVAL); } mutex_enter(&fdp->fd_lock); /* search if knote already exists */ if (kfilter->filtops->f_isfd) { /* monitoring a file descriptor */ fd = kev->ident; if ((fp = fd_getfile(fd)) == NULL) { mutex_exit(&fdp->fd_lock); rw_exit(&kqueue_filter_lock); kmem_free(newkn, sizeof(*newkn)); return EBADF; } ff = fdp->fd_ofiles[fd]; if (fd <= fdp->fd_lastkqfile) { SLIST_FOREACH(kn, &ff->ff_knlist, kn_link) { if (kq == kn->kn_kq && kev->filter == kn->kn_filter) break; } } } else { /* * not monitoring a file descriptor, so * lookup knotes in internal hash table */ if (fdp->fd_knhashmask != 0) { list = &fdp->fd_knhash[ KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)]; SLIST_FOREACH(kn, list, kn_link) { if (kev->ident == kn->kn_id && kq == kn->kn_kq && kev->filter == kn->kn_filter) break; } } } /* * kn now contains the matching knote, or NULL if no match */ if (kev->flags & EV_ADD) { if (kn == NULL) { /* create new knote */ kn = newkn; newkn = NULL; kn->kn_obj = fp; kn->kn_kq = kq; kn->kn_fop = kfilter->filtops; kn->kn_kfilter = kfilter; kn->kn_sfflags = kev->fflags; kn->kn_sdata = kev->data; kev->fflags = 0; kev->data = 0; kn->kn_kevent = *kev; /* * apply reference count to knote structure, and * do not release it at the end of this routine. */ fp = NULL; if (!kn->kn_fop->f_isfd) { /* * If knote is not on an fd, store on * internal hash table. */ if (fdp->fd_knhashmask == 0) { /* XXXAD can block with fd_lock held */ fdp->fd_knhash = hashinit(KN_HASHSIZE, HASH_LIST, true, &fdp->fd_knhashmask); } list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)]; } else { /* Otherwise, knote is on an fd. */ list = (struct klist *) &fdp->fd_ofiles[kn->kn_id]->ff_knlist; if ((int)kn->kn_id > fdp->fd_lastkqfile) fdp->fd_lastkqfile = kn->kn_id; } SLIST_INSERT_HEAD(list, kn, kn_link); KERNEL_LOCK(1, NULL); /* XXXSMP */ error = (*kfilter->filtops->f_attach)(kn); KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */ if (error != 0) { /* knote_detach() drops fdp->fd_lock */ knote_detach(kn, fdp, false); goto done; } atomic_inc_uint(&kfilter->refcnt); } else { /* * The user may change some filter values after the * initial EV_ADD, but doing so will not reset any * filter which have already been triggered. */ kn->kn_sfflags = kev->fflags; kn->kn_sdata = kev->data; kn->kn_kevent.udata = kev->udata; } KERNEL_LOCK(1, NULL); /* XXXSMP */ rv = (*kn->kn_fop->f_event)(kn, 0); KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */ if (rv) knote_activate(kn); } else { if (kn == NULL) { error = ENOENT; mutex_exit(&fdp->fd_lock); goto done; } if (kev->flags & EV_DELETE) { /* knote_detach() drops fdp->fd_lock */ knote_detach(kn, fdp, true); goto done; } } /* disable knote */ if ((kev->flags & EV_DISABLE)) { mutex_spin_enter(&kq->kq_lock); if ((kn->kn_status & KN_DISABLED) == 0) kn->kn_status |= KN_DISABLED; mutex_spin_exit(&kq->kq_lock); } /* enable knote */ if ((kev->flags & EV_ENABLE)) { knote_enqueue(kn); } mutex_exit(&fdp->fd_lock); done: rw_exit(&kqueue_filter_lock); if (newkn != NULL) kmem_free(newkn, sizeof(*newkn)); if (fp != NULL) fd_putfile(fd); return (error); } #if defined(DEBUG) static void kq_check(struct kqueue *kq) { const struct knote *kn; int count; int nmarker; KASSERT(mutex_owned(&kq->kq_lock)); KASSERT(kq->kq_count >= 0); count = 0; nmarker = 0; TAILQ_FOREACH(kn, &kq->kq_head, kn_tqe) { if ((kn->kn_status & (KN_MARKER | KN_QUEUED)) == 0) { panic("%s: kq=%p kn=%p inconsist 1", __func__, kq, kn); } if ((kn->kn_status & KN_MARKER) == 0) { if (kn->kn_kq != kq) { panic("%s: kq=%p kn=%p inconsist 2", __func__, kq, kn); } if ((kn->kn_status & KN_ACTIVE) == 0) { panic("%s: kq=%p kn=%p: not active", __func__, kq, kn); } count++; if (count > kq->kq_count) { goto bad; } } else { nmarker++; #if 0 if (nmarker > 10000) { panic("%s: kq=%p too many markers: %d != %d, " "nmarker=%d", __func__, kq, kq->kq_count, count, nmarker); } #endif } } if (kq->kq_count != count) { bad: panic("%s: kq=%p inconsist 3: %d != %d, nmarker=%d", __func__, kq, kq->kq_count, count, nmarker); } } #else /* defined(DEBUG) */ #define kq_check(a) /* nothing */ #endif /* defined(DEBUG) */ /* * Scan through the list of events on fp (for a maximum of maxevents), * returning the results in to ulistp. Timeout is determined by tsp; if * NULL, wait indefinitely, if 0 valued, perform a poll, otherwise wait * as appropriate. */ static int kqueue_scan(file_t *fp, size_t maxevents, struct kevent *ulistp, const struct timespec *tsp, register_t *retval, const struct kevent_ops *keops, struct kevent *kevbuf, size_t kevcnt) { struct kqueue *kq; struct kevent *kevp; struct timeval atv, sleeptv; struct knote *kn, *marker; size_t count, nkev, nevents; int timeout, error, rv; filedesc_t *fdp; fdp = curlwp->l_fd; kq = fp->f_data; count = maxevents; nkev = nevents = error = 0; if (count == 0) { *retval = 0; return 0; } if (tsp) { /* timeout supplied */ TIMESPEC_TO_TIMEVAL(&atv, tsp); if (inittimeleft(&atv, &sleeptv) == -1) { *retval = maxevents; return EINVAL; } timeout = tvtohz(&atv); if (timeout <= 0) timeout = -1; /* do poll */ } else { /* no timeout, wait forever */ timeout = 0; } marker = kmem_zalloc(sizeof(*marker), KM_SLEEP); marker->kn_status = KN_MARKER; mutex_spin_enter(&kq->kq_lock); retry: kevp = kevbuf; if (kq->kq_count == 0) { if (timeout >= 0) { error = cv_timedwait_sig(&kq->kq_cv, &kq->kq_lock, timeout); if (error == 0) { if (tsp == NULL || (timeout = gettimeleft(&atv, &sleeptv)) > 0) goto retry; } else { /* don't restart after signals... */ if (error == ERESTART) error = EINTR; if (error == EWOULDBLOCK) error = 0; } } } else { /* mark end of knote list */ TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); while (count != 0) { kn = TAILQ_FIRST(&kq->kq_head); /* get next knote */ while ((kn->kn_status & KN_MARKER) != 0) { if (kn == marker) { /* it's our marker, stop */ TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); if (count < maxevents || (tsp != NULL && (timeout = gettimeleft(&atv, &sleeptv)) <= 0)) goto done; goto retry; } /* someone else's marker. */ kn = TAILQ_NEXT(kn, kn_tqe); } kq_check(kq); TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); kq->kq_count--; kn->kn_status &= ~KN_QUEUED; kq_check(kq); if (kn->kn_status & KN_DISABLED) { /* don't want disabled events */ continue; } if ((kn->kn_flags & EV_ONESHOT) == 0) { mutex_spin_exit(&kq->kq_lock); KERNEL_LOCK(1, NULL); /* XXXSMP */ rv = (*kn->kn_fop->f_event)(kn, 0); KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */ mutex_spin_enter(&kq->kq_lock); /* Re-poll if note was re-enqueued. */ if ((kn->kn_status & KN_QUEUED) != 0) continue; if (rv == 0) { /* * non-ONESHOT event that hasn't * triggered again, so de-queue. */ kn->kn_status &= ~KN_ACTIVE; continue; } } /* XXXAD should be got from f_event if !oneshot. */ *kevp++ = kn->kn_kevent; nkev++; if (kn->kn_flags & EV_ONESHOT) { /* delete ONESHOT events after retrieval */ mutex_spin_exit(&kq->kq_lock); mutex_enter(&fdp->fd_lock); knote_detach(kn, fdp, true); mutex_spin_enter(&kq->kq_lock); } else if (kn->kn_flags & EV_CLEAR) { /* clear state after retrieval */ kn->kn_data = 0; kn->kn_fflags = 0; kn->kn_status &= ~KN_ACTIVE; } else { /* add event back on list */ kq_check(kq); TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); kq->kq_count++; kn->kn_status |= KN_QUEUED; kq_check(kq); } if (nkev == kevcnt) { /* do copyouts in kevcnt chunks */ mutex_spin_exit(&kq->kq_lock); error = (*keops->keo_put_events) (keops->keo_private, kevbuf, ulistp, nevents, nkev); mutex_spin_enter(&kq->kq_lock); nevents += nkev; nkev = 0; kevp = kevbuf; } count--; if (error != 0 || count == 0) { /* remove marker */ TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); break; } } } done: mutex_spin_exit(&kq->kq_lock); if (marker != NULL) kmem_free(marker, sizeof(*marker)); if (nkev != 0) { /* copyout remaining events */ error = (*keops->keo_put_events)(keops->keo_private, kevbuf, ulistp, nevents, nkev); } *retval = maxevents - count; return error; } /* * fileops ioctl method for a kqueue descriptor. * * Two ioctls are currently supported. They both use struct kfilter_mapping: * KFILTER_BYNAME find name for filter, and return result in * name, which is of size len. * KFILTER_BYFILTER find filter for name. len is ignored. */ /*ARGSUSED*/ static int kqueue_ioctl(file_t *fp, u_long com, void *data) { struct kfilter_mapping *km; const struct kfilter *kfilter; char *name; int error; km = data; error = 0; name = kmem_alloc(KFILTER_MAXNAME, KM_SLEEP); switch (com) { case KFILTER_BYFILTER: /* convert filter -> name */ rw_enter(&kqueue_filter_lock, RW_READER); kfilter = kfilter_byfilter(km->filter); if (kfilter != NULL) { strlcpy(name, kfilter->name, KFILTER_MAXNAME); rw_exit(&kqueue_filter_lock); error = copyoutstr(name, km->name, km->len, NULL); } else { rw_exit(&kqueue_filter_lock); error = ENOENT; } break; case KFILTER_BYNAME: /* convert name -> filter */ error = copyinstr(km->name, name, KFILTER_MAXNAME, NULL); if (error) { break; } rw_enter(&kqueue_filter_lock, RW_READER); kfilter = kfilter_byname(name); if (kfilter != NULL) km->filter = kfilter->filter; else error = ENOENT; rw_exit(&kqueue_filter_lock); break; default: error = ENOTTY; break; } kmem_free(name, KFILTER_MAXNAME); return (error); } /* * fileops fcntl method for a kqueue descriptor. */ static int kqueue_fcntl(file_t *fp, u_int com, void *data) { return (ENOTTY); } /* * fileops poll method for a kqueue descriptor. * Determine if kqueue has events pending. */ static int kqueue_poll(file_t *fp, int events) { struct kqueue *kq; int revents; kq = fp->f_data; revents = 0; if (events & (POLLIN | POLLRDNORM)) { mutex_spin_enter(&kq->kq_lock); if (kq->kq_count != 0) { revents |= events & (POLLIN | POLLRDNORM); } else { selrecord(curlwp, &kq->kq_sel); } kq_check(kq); mutex_spin_exit(&kq->kq_lock); } return revents; } /* * fileops stat method for a kqueue descriptor. * Returns dummy info, with st_size being number of events pending. */ static int kqueue_stat(file_t *fp, struct stat *st) { struct kqueue *kq; kq = fp->f_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; } static void kqueue_doclose(struct kqueue *kq, struct klist *list, int fd) { struct knote *kn; filedesc_t *fdp; fdp = kq->kq_fdp; KASSERT(mutex_owned(&fdp->fd_lock)); for (kn = SLIST_FIRST(list); kn != NULL;) { if (kq != kn->kn_kq) { kn = SLIST_NEXT(kn, kn_link); continue; } knote_detach(kn, fdp, true); mutex_enter(&fdp->fd_lock); kn = SLIST_FIRST(list); } } /* * fileops close method for a kqueue descriptor. */ static int kqueue_close(file_t *fp) { struct kqueue *kq; filedesc_t *fdp; fdfile_t *ff; int i; kq = fp->f_data; fdp = curlwp->l_fd; mutex_enter(&fdp->fd_lock); for (i = 0; i <= fdp->fd_lastkqfile; i++) { if ((ff = fdp->fd_ofiles[i]) == NULL) continue; kqueue_doclose(kq, (struct klist *)&ff->ff_knlist, i); } if (fdp->fd_knhashmask != 0) { for (i = 0; i < fdp->fd_knhashmask + 1; i++) { kqueue_doclose(kq, &fdp->fd_knhash[i], -1); } } mutex_exit(&fdp->fd_lock); KASSERT(kq->kq_count == 0); mutex_destroy(&kq->kq_lock); cv_destroy(&kq->kq_cv); seldestroy(&kq->kq_sel); kmem_free(kq, sizeof(*kq)); fp->f_data = NULL; return (0); } /* * struct fileops kqfilter method for a kqueue descriptor. * Event triggered when monitored kqueue changes. */ static int kqueue_kqfilter(file_t *fp, struct knote *kn) { struct kqueue *kq; filedesc_t *fdp; kq = ((file_t *)kn->kn_obj)->f_data; KASSERT(fp == kn->kn_obj); if (kn->kn_filter != EVFILT_READ) return 1; kn->kn_fop = &kqread_filtops; fdp = curlwp->l_fd; mutex_enter(&kq->kq_lock); SLIST_INSERT_HEAD(&kq->kq_sel.sel_klist, kn, kn_selnext); mutex_exit(&kq->kq_lock); return 0; } /* * Walk down a list of knotes, activating them if their event has * triggered. The caller's object lock (e.g. device driver lock) * must be held. */ void knote(struct klist *list, long hint) { struct knote *kn; SLIST_FOREACH(kn, list, kn_selnext) { if ((*kn->kn_fop->f_event)(kn, hint)) knote_activate(kn); } } /* * Remove all knotes referencing a specified fd */ void knote_fdclose(int fd) { struct klist *list; struct knote *kn; filedesc_t *fdp; fdp = curlwp->l_fd; list = (struct klist *)&fdp->fd_ofiles[fd]->ff_knlist; mutex_enter(&fdp->fd_lock); while ((kn = SLIST_FIRST(list)) != NULL) { knote_detach(kn, fdp, true); mutex_enter(&fdp->fd_lock); } mutex_exit(&fdp->fd_lock); } /* * Drop knote. Called with fdp->fd_lock held, and will drop before * returning. */ static void knote_detach(struct knote *kn, filedesc_t *fdp, bool dofop) { struct klist *list; struct kqueue *kq; kq = kn->kn_kq; KASSERT((kn->kn_status & KN_MARKER) == 0); KASSERT(mutex_owned(&fdp->fd_lock)); /* Remove from monitored object. */ if (dofop) { KERNEL_LOCK(1, NULL); /* XXXSMP */ (*kn->kn_fop->f_detach)(kn); KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */ } /* Remove from descriptor table. */ if (kn->kn_fop->f_isfd) list = (struct klist *)&fdp->fd_ofiles[kn->kn_id]->ff_knlist; else list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)]; SLIST_REMOVE(list, kn, knote, kn_link); /* Remove from kqueue. */ /* XXXAD should verify not in use by kqueue_scan. */ mutex_spin_enter(&kq->kq_lock); if ((kn->kn_status & KN_QUEUED) != 0) { kq_check(kq); TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); kn->kn_status &= ~KN_QUEUED; kq->kq_count--; kq_check(kq); } mutex_spin_exit(&kq->kq_lock); mutex_exit(&fdp->fd_lock); if (kn->kn_fop->f_isfd) fd_putfile(kn->kn_id); atomic_dec_uint(&kn->kn_kfilter->refcnt); kmem_free(kn, sizeof(*kn)); } /* * Queue new event for knote. */ static void knote_enqueue(struct knote *kn) { struct kqueue *kq; KASSERT((kn->kn_status & KN_MARKER) == 0); kq = kn->kn_kq; mutex_spin_enter(&kq->kq_lock); if ((kn->kn_status & KN_DISABLED) != 0) { kn->kn_status &= ~KN_DISABLED; } if ((kn->kn_status & (KN_ACTIVE | KN_QUEUED)) == KN_ACTIVE) { kq_check(kq); TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); kn->kn_status |= KN_QUEUED; kq->kq_count++; kq_check(kq); cv_broadcast(&kq->kq_cv); selnotify(&kq->kq_sel, 0, NOTE_SUBMIT); } mutex_spin_exit(&kq->kq_lock); } /* * Queue new event for knote. */ static void knote_activate(struct knote *kn) { struct kqueue *kq; KASSERT((kn->kn_status & KN_MARKER) == 0); kq = kn->kn_kq; mutex_spin_enter(&kq->kq_lock); kn->kn_status |= KN_ACTIVE; if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) { kq_check(kq); TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); kn->kn_status |= KN_QUEUED; kq->kq_count++; kq_check(kq); cv_broadcast(&kq->kq_cv); selnotify(&kq->kq_sel, 0, NOTE_SUBMIT); } mutex_spin_exit(&kq->kq_lock); }