/* $NetBSD: devpoll.c,v 1.1.1.2 2017/01/31 21:14:52 christos Exp $ */ /* * Copyright 2000-2009 Niels Provos * Copyright 2009-2012 Niels Provos and Nick Mathewson * * 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. */ #include "event2/event-config.h" #include __RCSID("$NetBSD: devpoll.c,v 1.1.1.2 2017/01/31 21:14:52 christos Exp $"); #include "evconfig-private.h" #ifdef EVENT__HAVE_DEVPOLL #include #include #ifdef EVENT__HAVE_SYS_TIME_H #include #endif #include #include #include #include #include #include #include #include #include #include "event2/event.h" #include "event2/event_struct.h" #include "event2/thread.h" #include "event-internal.h" #include "evsignal-internal.h" #include "log-internal.h" #include "evmap-internal.h" #include "evthread-internal.h" struct devpollop { struct pollfd *events; int nevents; int dpfd; struct pollfd *changes; int nchanges; }; static void *devpoll_init(struct event_base *); static int devpoll_add(struct event_base *, int fd, short old, short events, void *); static int devpoll_del(struct event_base *, int fd, short old, short events, void *); static int devpoll_dispatch(struct event_base *, struct timeval *); static void devpoll_dealloc(struct event_base *); const struct eventop devpollops = { "devpoll", devpoll_init, devpoll_add, devpoll_del, devpoll_dispatch, devpoll_dealloc, 1, /* need reinit */ EV_FEATURE_FDS|EV_FEATURE_O1, 0 }; #define NEVENT 32000 static int devpoll_commit(struct devpollop *devpollop) { /* * Due to a bug in Solaris, we have to use pwrite with an offset of 0. * Write is limited to 2GB of data, until it will fail. */ if (pwrite(devpollop->dpfd, devpollop->changes, sizeof(struct pollfd) * devpollop->nchanges, 0) == -1) return (-1); devpollop->nchanges = 0; return (0); } static int devpoll_queue(struct devpollop *devpollop, int fd, int events) { struct pollfd *pfd; if (devpollop->nchanges >= devpollop->nevents) { /* * Change buffer is full, must commit it to /dev/poll before * adding more */ if (devpoll_commit(devpollop) != 0) return (-1); } pfd = &devpollop->changes[devpollop->nchanges++]; pfd->fd = fd; pfd->events = events; pfd->revents = 0; return (0); } static void * devpoll_init(struct event_base *base) { int dpfd, nfiles = NEVENT; struct rlimit rl; struct devpollop *devpollop; if (!(devpollop = mm_calloc(1, sizeof(struct devpollop)))) return (NULL); if (getrlimit(RLIMIT_NOFILE, &rl) == 0 && rl.rlim_cur != RLIM_INFINITY) nfiles = rl.rlim_cur; /* Initialize the kernel queue */ if ((dpfd = evutil_open_closeonexec_("/dev/poll", O_RDWR, 0)) == -1) { event_warn("open: /dev/poll"); mm_free(devpollop); return (NULL); } devpollop->dpfd = dpfd; /* Initialize fields */ /* FIXME: allocating 'nfiles' worth of space here can be * expensive and unnecessary. See how epoll.c does it instead. */ devpollop->events = mm_calloc(nfiles, sizeof(struct pollfd)); if (devpollop->events == NULL) { mm_free(devpollop); close(dpfd); return (NULL); } devpollop->nevents = nfiles; devpollop->changes = mm_calloc(nfiles, sizeof(struct pollfd)); if (devpollop->changes == NULL) { mm_free(devpollop->events); mm_free(devpollop); close(dpfd); return (NULL); } evsig_init_(base); return (devpollop); } static int devpoll_dispatch(struct event_base *base, struct timeval *tv) { struct devpollop *devpollop = base->evbase; struct pollfd *events = devpollop->events; struct dvpoll dvp; int i, res, timeout = -1; if (devpollop->nchanges) devpoll_commit(devpollop); if (tv != NULL) timeout = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000; dvp.dp_fds = devpollop->events; dvp.dp_nfds = devpollop->nevents; dvp.dp_timeout = timeout; EVBASE_RELEASE_LOCK(base, th_base_lock); res = ioctl(devpollop->dpfd, DP_POLL, &dvp); EVBASE_ACQUIRE_LOCK(base, th_base_lock); if (res == -1) { if (errno != EINTR) { event_warn("ioctl: DP_POLL"); return (-1); } return (0); } event_debug(("%s: devpoll_wait reports %d", __func__, res)); for (i = 0; i < res; i++) { int which = 0; int what = events[i].revents; if (what & POLLHUP) what |= POLLIN | POLLOUT; else if (what & POLLERR) what |= POLLIN | POLLOUT; if (what & POLLIN) which |= EV_READ; if (what & POLLOUT) which |= EV_WRITE; if (!which) continue; /* XXX(niels): not sure if this works for devpoll */ evmap_io_active_(base, events[i].fd, which); } return (0); } static int devpoll_add(struct event_base *base, int fd, short old, short events, void *p) { struct devpollop *devpollop = base->evbase; int res; (void)p; /* * It's not necessary to OR the existing read/write events that we * are currently interested in with the new event we are adding. * The /dev/poll driver ORs any new events with the existing events * that it has cached for the fd. */ res = 0; if (events & EV_READ) res |= POLLIN; if (events & EV_WRITE) res |= POLLOUT; if (devpoll_queue(devpollop, fd, res) != 0) return (-1); return (0); } static int devpoll_del(struct event_base *base, int fd, short old, short events, void *p) { struct devpollop *devpollop = base->evbase; int res; (void)p; res = 0; if (events & EV_READ) res |= POLLIN; if (events & EV_WRITE) res |= POLLOUT; /* * The only way to remove an fd from the /dev/poll monitored set is * to use POLLREMOVE by itself. This removes ALL events for the fd * provided so if we care about two events and are only removing one * we must re-add the other event after POLLREMOVE. */ if (devpoll_queue(devpollop, fd, POLLREMOVE) != 0) return (-1); if ((res & (POLLIN|POLLOUT)) != (POLLIN|POLLOUT)) { /* * We're not deleting all events, so we must resubmit the * event that we are still interested in if one exists. */ if ((res & POLLIN) && (old & EV_WRITE)) { /* Deleting read, still care about write */ devpoll_queue(devpollop, fd, POLLOUT); } else if ((res & POLLOUT) && (old & EV_READ)) { /* Deleting write, still care about read */ devpoll_queue(devpollop, fd, POLLIN); } } return (0); } static void devpoll_dealloc(struct event_base *base) { struct devpollop *devpollop = base->evbase; evsig_dealloc_(base); if (devpollop->events) mm_free(devpollop->events); if (devpollop->changes) mm_free(devpollop->changes); if (devpollop->dpfd >= 0) close(devpollop->dpfd); memset(devpollop, 0, sizeof(struct devpollop)); mm_free(devpollop); } #endif /* EVENT__HAVE_DEVPOLL */