/* $NetBSD: poll.c,v 1.1.1.4 2021/04/07 02:43:13 christos Exp $ */ /* $OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */ /* * Copyright 2000-2007 Niels Provos * Copyright 2007-2012 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: poll.c,v 1.1.1.4 2021/04/07 02:43:13 christos Exp $"); #include "evconfig-private.h" #ifdef EVENT__HAVE_POLL #include #ifdef EVENT__HAVE_SYS_TIME_H #include #endif #include #include #include #include #include #include #include #include #include #include "event-internal.h" #include "evsignal-internal.h" #include "log-internal.h" #include "evmap-internal.h" #include "event2/thread.h" #include "evthread-internal.h" #include "time-internal.h" /* Since Linux 2.6.17, poll is able to report about peer half-closed connection using special POLLRDHUP flag on a read event. */ #if !defined(POLLRDHUP) #define POLLRDHUP 0 #define EARLY_CLOSE_IF_HAVE_RDHUP 0 #else #define EARLY_CLOSE_IF_HAVE_RDHUP EV_FEATURE_EARLY_CLOSE #endif struct pollidx { int idxplus1; }; struct pollop { int event_count; /* Highest number alloc */ int nfds; /* Highest number used */ int realloc_copy; /* True iff we must realloc * event_set_copy */ struct pollfd *event_set; struct pollfd *event_set_copy; }; static void *poll_init(struct event_base *); static int poll_add(struct event_base *, int, short old, short events, void *idx); static int poll_del(struct event_base *, int, short old, short events, void *idx); static int poll_dispatch(struct event_base *, struct timeval *); static void poll_dealloc(struct event_base *); const struct eventop pollops = { "poll", poll_init, poll_add, poll_del, poll_dispatch, poll_dealloc, 1, /* need_reinit */ EV_FEATURE_FDS|EARLY_CLOSE_IF_HAVE_RDHUP, sizeof(struct pollidx), }; static void * poll_init(struct event_base *base) { struct pollop *pollop; if (!(pollop = mm_calloc(1, sizeof(struct pollop)))) return (NULL); evsig_init_(base); evutil_weakrand_seed_(&base->weakrand_seed, 0); return (pollop); } #ifdef CHECK_INVARIANTS static void poll_check_ok(struct pollop *pop) { int i, idx; struct event *ev; for (i = 0; i < pop->fd_count; ++i) { idx = pop->idxplus1_by_fd[i]-1; if (idx < 0) continue; EVUTIL_ASSERT(pop->event_set[idx].fd == i); } for (i = 0; i < pop->nfds; ++i) { struct pollfd *pfd = &pop->event_set[i]; EVUTIL_ASSERT(pop->idxplus1_by_fd[pfd->fd] == i+1); } } #else #define poll_check_ok(pop) #endif static int poll_dispatch(struct event_base *base, struct timeval *tv) { int res, i, j, nfds; long msec = -1; struct pollop *pop = base->evbase; struct pollfd *event_set; poll_check_ok(pop); nfds = pop->nfds; #ifndef EVENT__DISABLE_THREAD_SUPPORT if (base->th_base_lock) { /* If we're using this backend in a multithreaded setting, * then we need to work on a copy of event_set, so that we can * let other threads modify the main event_set while we're * polling. If we're not multithreaded, then we'll skip the * copy step here to save memory and time. */ if (pop->realloc_copy) { struct pollfd *tmp = mm_realloc(pop->event_set_copy, pop->event_count * sizeof(struct pollfd)); if (tmp == NULL) { event_warn("realloc"); return -1; } pop->event_set_copy = tmp; pop->realloc_copy = 0; } memcpy(pop->event_set_copy, pop->event_set, sizeof(struct pollfd)*nfds); event_set = pop->event_set_copy; } else { event_set = pop->event_set; } #else event_set = pop->event_set; #endif if (tv != NULL) { msec = evutil_tv_to_msec_(tv); if (msec < 0 || msec > INT_MAX) msec = INT_MAX; } EVBASE_RELEASE_LOCK(base, th_base_lock); res = poll(event_set, nfds, msec); EVBASE_ACQUIRE_LOCK(base, th_base_lock); if (res == -1) { if (errno != EINTR) { event_warn("poll"); return (-1); } return (0); } event_debug(("%s: poll reports %d", __func__, res)); if (res == 0 || nfds == 0) return (0); i = evutil_weakrand_range_(&base->weakrand_seed, nfds); for (j = 0; j < nfds; j++) { int what; if (++i == nfds) i = 0; what = event_set[i].revents; if (!what) continue; res = 0; /* If the file gets closed notify */ if (what & (POLLHUP|POLLERR|POLLNVAL)) what |= POLLIN|POLLOUT; if (what & POLLIN) res |= EV_READ; if (what & POLLOUT) res |= EV_WRITE; if (what & POLLRDHUP) res |= EV_CLOSED; if (res == 0) continue; evmap_io_active_(base, event_set[i].fd, res); } return (0); } static int poll_add(struct event_base *base, int fd, short old, short events, void *idx_) { struct pollop *pop = base->evbase; struct pollfd *pfd = NULL; struct pollidx *idx = idx_; int i; EVUTIL_ASSERT((events & EV_SIGNAL) == 0); if (!(events & (EV_READ|EV_WRITE|EV_CLOSED))) return (0); poll_check_ok(pop); if (pop->nfds + 1 >= pop->event_count) { struct pollfd *tmp_event_set; int tmp_event_count; if (pop->event_count < 32) tmp_event_count = 32; else tmp_event_count = pop->event_count * 2; /* We need more file descriptors */ tmp_event_set = mm_realloc(pop->event_set, tmp_event_count * sizeof(struct pollfd)); if (tmp_event_set == NULL) { event_warn("realloc"); return (-1); } pop->event_set = tmp_event_set; pop->event_count = tmp_event_count; pop->realloc_copy = 1; } i = idx->idxplus1 - 1; if (i >= 0) { pfd = &pop->event_set[i]; } else { i = pop->nfds++; pfd = &pop->event_set[i]; pfd->events = 0; pfd->fd = fd; idx->idxplus1 = i + 1; } pfd->revents = 0; if (events & EV_WRITE) pfd->events |= POLLOUT; if (events & EV_READ) pfd->events |= POLLIN; if (events & EV_CLOSED) pfd->events |= POLLRDHUP; poll_check_ok(pop); return (0); } /* * Nothing to be done here. */ static int poll_del(struct event_base *base, int fd, short old, short events, void *idx_) { struct pollop *pop = base->evbase; struct pollfd *pfd = NULL; struct pollidx *idx = idx_; int i; EVUTIL_ASSERT((events & EV_SIGNAL) == 0); if (!(events & (EV_READ|EV_WRITE|EV_CLOSED))) return (0); poll_check_ok(pop); i = idx->idxplus1 - 1; if (i < 0) return (-1); /* Do we still want to read or write? */ pfd = &pop->event_set[i]; if (events & EV_READ) pfd->events &= ~POLLIN; if (events & EV_WRITE) pfd->events &= ~POLLOUT; if (events & EV_CLOSED) pfd->events &= ~POLLRDHUP; poll_check_ok(pop); if (pfd->events) /* Another event cares about that fd. */ return (0); /* Okay, so we aren't interested in that fd anymore. */ idx->idxplus1 = 0; --pop->nfds; if (i != pop->nfds) { /* * Shift the last pollfd down into the now-unoccupied * position. */ memcpy(&pop->event_set[i], &pop->event_set[pop->nfds], sizeof(struct pollfd)); idx = evmap_io_get_fdinfo_(&base->io, pop->event_set[i].fd); EVUTIL_ASSERT(idx); EVUTIL_ASSERT(idx->idxplus1 == pop->nfds + 1); idx->idxplus1 = i + 1; } poll_check_ok(pop); return (0); } static void poll_dealloc(struct event_base *base) { struct pollop *pop = base->evbase; evsig_dealloc_(base); if (pop->event_set) mm_free(pop->event_set); if (pop->event_set_copy) mm_free(pop->event_set_copy); memset(pop, 0, sizeof(struct pollop)); mm_free(pop); } #endif /* EVENT__HAVE_POLL */