/* $OpenBSD: kqueue.c,v 1.29 2014/10/08 05:41:42 deraadt Exp $ */ /* * Copyright 2000-2002 Niels Provos * 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. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #define _GNU_SOURCE 1 #include #ifdef HAVE_SYS_TIME_H #include #else #include #endif #include #include #include #include #include #include #include #include #include #ifdef HAVE_INTTYPES_H #include #endif /* Some platforms apparently define the udata field of struct kevent as * intptr_t, whereas others define it as void*. There doesn't seem to be an * easy way to tell them apart via autoconf, so we need to use OS macros. */ #if defined(HAVE_INTTYPES_H) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__darwin__) && !defined(__APPLE__) #define PTR_TO_UDATA(x) ((intptr_t)(x)) #else #define PTR_TO_UDATA(x) (x) #endif #include "event.h" #include "event-internal.h" #include "log.h" #include "evsignal.h" #define EVLIST_X_KQINKERNEL 0x1000 #define NEVENT 64 struct kqop { struct kevent *changes; int nchanges; struct kevent *events; struct event_list evsigevents[NSIG]; int nevents; int kq; pid_t pid; }; static void *kq_init (struct event_base *); static int kq_add (void *, struct event *); static int kq_del (void *, struct event *); static int kq_dispatch (struct event_base *, void *, struct timeval *); static int kq_insert (struct kqop *, struct kevent *); static void kq_dealloc (struct event_base *, void *); const struct eventop kqops = { "kqueue", kq_init, kq_add, kq_del, kq_dispatch, kq_dealloc, 1 /* need reinit */ }; static void * kq_init(struct event_base *base) { int i, kq; struct kqop *kqueueop; /* Disable kqueue when this environment variable is set */ if (evutil_getenv("EVENT_NOKQUEUE")) return (NULL); if (!(kqueueop = calloc(1, sizeof(struct kqop)))) return (NULL); /* Initalize the kernel queue */ if ((kq = kqueue()) == -1) { event_warn("kqueue"); free (kqueueop); return (NULL); } kqueueop->kq = kq; kqueueop->pid = getpid(); /* Initalize fields */ kqueueop->changes = calloc(NEVENT, sizeof(struct kevent)); if (kqueueop->changes == NULL) { free (kqueueop); return (NULL); } kqueueop->events = calloc(NEVENT, sizeof(struct kevent)); if (kqueueop->events == NULL) { free (kqueueop->changes); free (kqueueop); return (NULL); } kqueueop->nevents = NEVENT; /* we need to keep track of multiple events per signal */ for (i = 0; i < NSIG; ++i) { TAILQ_INIT(&kqueueop->evsigevents[i]); } /* Check for Mac OS X kqueue bug. */ kqueueop->changes[0].ident = -1; kqueueop->changes[0].filter = EVFILT_READ; kqueueop->changes[0].flags = EV_ADD; /* * If kqueue works, then kevent will succeed, and it will * stick an error in events[0]. If kqueue is broken, then * kevent will fail. */ if (kevent(kq, kqueueop->changes, 1, kqueueop->events, NEVENT, NULL) != 1 || kqueueop->events[0].ident != -1 || kqueueop->events[0].flags != EV_ERROR) { event_warn("%s: detected broken kqueue; not using.", __func__); free(kqueueop->changes); free(kqueueop->events); free(kqueueop); close(kq); return (NULL); } return (kqueueop); } static int kq_insert(struct kqop *kqop, struct kevent *kev) { int nevents = kqop->nevents; if (kqop->nchanges == nevents) { struct kevent *newchange; struct kevent *newresult; nevents *= 2; newchange = reallocarray(kqop->changes, nevents, sizeof(struct kevent)); if (newchange == NULL) { event_warn("%s: malloc", __func__); return (-1); } kqop->changes = newchange; newresult = reallocarray(kqop->events, nevents, sizeof(struct kevent)); /* * If we fail, we don't have to worry about freeing, * the next realloc will pick it up. */ if (newresult == NULL) { event_warn("%s: malloc", __func__); return (-1); } kqop->events = newresult; kqop->nevents = nevents; } memcpy(&kqop->changes[kqop->nchanges++], kev, sizeof(struct kevent)); event_debug(("%s: fd %d %s%s", __func__, (int)kev->ident, kev->filter == EVFILT_READ ? "EVFILT_READ" : "EVFILT_WRITE", kev->flags == EV_DELETE ? " (del)" : "")); return (0); } static void kq_sighandler(int sig) { /* Do nothing here */ } static int kq_dispatch(struct event_base *base, void *arg, struct timeval *tv) { struct kqop *kqop = arg; struct kevent *changes = kqop->changes; struct kevent *events = kqop->events; struct event *ev; struct timespec ts, *ts_p = NULL; int i, res; if (tv != NULL) { TIMEVAL_TO_TIMESPEC(tv, &ts); ts_p = &ts; } res = kevent(kqop->kq, changes, kqop->nchanges, events, kqop->nevents, ts_p); kqop->nchanges = 0; if (res == -1) { if (errno != EINTR) { event_warn("kevent"); return (-1); } return (0); } event_debug(("%s: kevent reports %d", __func__, res)); for (i = 0; i < res; i++) { int which = 0; if (events[i].flags & EV_ERROR) { switch (events[i].data) { /* Can occur on delete if we are not currently * watching any events on this fd. That can * happen when the fd was closed and another * file was opened with that fd. */ case ENOENT: /* Can occur for reasons not fully understood * on FreeBSD. */ case EINVAL: continue; /* Can occur on a delete if the fd is closed. Can * occur on an add if the fd was one side of a pipe, * and the other side was closed. */ case EBADF: continue; /* These two can occur on an add if the fd was one side * of a pipe, and the other side was closed. */ case EPERM: case EPIPE: /* Report read events, if we're listening for * them, so that the user can learn about any * add errors. (If the operation was a * delete, then udata should be cleared.) */ if (events[i].udata) { /* The operation was an add: * report the error as a read. */ which |= EV_READ; break; } else { /* The operation was a del: * report nothing. */ continue; } /* Other errors shouldn't occur. */ default: errno = events[i].data; return (-1); } } else if (events[i].filter == EVFILT_READ) { which |= EV_READ; } else if (events[i].filter == EVFILT_WRITE) { which |= EV_WRITE; } else if (events[i].filter == EVFILT_SIGNAL) { which |= EV_SIGNAL; } if (!which) continue; if (events[i].filter == EVFILT_SIGNAL) { struct event_list *head = (struct event_list *)events[i].udata; TAILQ_FOREACH(ev, head, ev_signal_next) { event_active(ev, which, events[i].data); } } else { ev = (struct event *)events[i].udata; if (!(ev->ev_events & EV_PERSIST)) ev->ev_flags &= ~EVLIST_X_KQINKERNEL; event_active(ev, which, 1); } } return (0); } static int kq_add(void *arg, struct event *ev) { struct kqop *kqop = arg; struct kevent kev; if (ev->ev_events & EV_SIGNAL) { int nsignal = EVENT_SIGNAL(ev); assert(nsignal >= 0 && nsignal < NSIG); if (TAILQ_EMPTY(&kqop->evsigevents[nsignal])) { struct timespec timeout = { 0, 0 }; memset(&kev, 0, sizeof(kev)); kev.ident = nsignal; kev.filter = EVFILT_SIGNAL; kev.flags = EV_ADD; kev.udata = PTR_TO_UDATA(&kqop->evsigevents[nsignal]); /* Be ready for the signal if it is sent any * time between now and the next call to * kq_dispatch. */ if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1) return (-1); if (_evsignal_set_handler(ev->ev_base, nsignal, kq_sighandler) == -1) return (-1); } TAILQ_INSERT_TAIL(&kqop->evsigevents[nsignal], ev, ev_signal_next); ev->ev_flags |= EVLIST_X_KQINKERNEL; return (0); } if (ev->ev_events & EV_READ) { memset(&kev, 0, sizeof(kev)); kev.ident = ev->ev_fd; kev.filter = EVFILT_READ; #ifdef NOTE_EOF /* Make it behave like select() and poll() */ kev.fflags = NOTE_EOF; #endif kev.flags = EV_ADD; if (!(ev->ev_events & EV_PERSIST)) kev.flags |= EV_ONESHOT; kev.udata = PTR_TO_UDATA(ev); if (kq_insert(kqop, &kev) == -1) return (-1); ev->ev_flags |= EVLIST_X_KQINKERNEL; } if (ev->ev_events & EV_WRITE) { memset(&kev, 0, sizeof(kev)); kev.ident = ev->ev_fd; kev.filter = EVFILT_WRITE; kev.flags = EV_ADD; if (!(ev->ev_events & EV_PERSIST)) kev.flags |= EV_ONESHOT; kev.udata = PTR_TO_UDATA(ev); if (kq_insert(kqop, &kev) == -1) return (-1); ev->ev_flags |= EVLIST_X_KQINKERNEL; } return (0); } static int kq_del(void *arg, struct event *ev) { struct kqop *kqop = arg; struct kevent kev; if (!(ev->ev_flags & EVLIST_X_KQINKERNEL)) return (0); if (ev->ev_events & EV_SIGNAL) { int nsignal = EVENT_SIGNAL(ev); struct timespec timeout = { 0, 0 }; assert(nsignal >= 0 && nsignal < NSIG); TAILQ_REMOVE(&kqop->evsigevents[nsignal], ev, ev_signal_next); if (TAILQ_EMPTY(&kqop->evsigevents[nsignal])) { memset(&kev, 0, sizeof(kev)); kev.ident = nsignal; kev.filter = EVFILT_SIGNAL; kev.flags = EV_DELETE; /* Because we insert signal events * immediately, we need to delete them * immediately, too */ if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1) return (-1); if (_evsignal_restore_handler(ev->ev_base, nsignal) == -1) return (-1); } ev->ev_flags &= ~EVLIST_X_KQINKERNEL; return (0); } if (ev->ev_events & EV_READ) { memset(&kev, 0, sizeof(kev)); kev.ident = ev->ev_fd; kev.filter = EVFILT_READ; kev.flags = EV_DELETE; if (kq_insert(kqop, &kev) == -1) return (-1); ev->ev_flags &= ~EVLIST_X_KQINKERNEL; } if (ev->ev_events & EV_WRITE) { memset(&kev, 0, sizeof(kev)); kev.ident = ev->ev_fd; kev.filter = EVFILT_WRITE; kev.flags = EV_DELETE; if (kq_insert(kqop, &kev) == -1) return (-1); ev->ev_flags &= ~EVLIST_X_KQINKERNEL; } return (0); } static void kq_dealloc(struct event_base *base, void *arg) { struct kqop *kqop = arg; evsignal_dealloc(base); if (kqop->changes) free(kqop->changes); if (kqop->events) free(kqop->events); if (kqop->kq >= 0 && kqop->pid == getpid()) close(kqop->kq); memset(kqop, 0, sizeof(struct kqop)); free(kqop); }