/release/src/router/libevent/evport.c
C | 473 lines | 262 code | 76 blank | 135 comment | 62 complexity | dc10e9596e7536c932590c8b88fbdbe5 MD5 | raw file
- /*
- * Submitted by David Pacheco (dp.spambait@gmail.com)
- *
- * Copyright 2006-2007 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 SUN MICROSYSTEMS, INC. ``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 SUN MICROSYSTEMS, INC. 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) 2007 Sun Microsystems. All rights reserved.
- * Use is subject to license terms.
- */
- /*
- * evport.c: event backend using Solaris 10 event ports. See port_create(3C).
- * This implementation is loosely modeled after the one used for select(2) (in
- * select.c).
- *
- * The outstanding events are tracked in a data structure called evport_data.
- * Each entry in the ed_fds array corresponds to a file descriptor, and contains
- * pointers to the read and write events that correspond to that fd. (That is,
- * when the file is readable, the "read" event should handle it, etc.)
- *
- * evport_add and evport_del update this data structure. evport_dispatch uses it
- * to determine where to callback when an event occurs (which it gets from
- * port_getn).
- *
- * Helper functions are used: grow() grows the file descriptor array as
- * necessary when large fd's come in. reassociate() takes care of maintaining
- * the proper file-descriptor/event-port associations.
- *
- * As in the select(2) implementation, signals are handled by evsignal.
- */
- #include "event2/event-config.h"
- #include <sys/time.h>
- #include <sys/queue.h>
- #include <errno.h>
- #include <poll.h>
- #include <port.h>
- #include <signal.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <time.h>
- #include <unistd.h>
- #include "event2/thread.h"
- #include "evthread-internal.h"
- #include "event-internal.h"
- #include "log-internal.h"
- #include "evsignal-internal.h"
- #include "evmap-internal.h"
- /*
- * Default value for ed_nevents, which is the maximum file descriptor number we
- * can handle. If an event comes in for a file descriptor F > nevents, we will
- * grow the array of file descriptors, doubling its size.
- */
- #define DEFAULT_NFDS 16
- /*
- * EVENTS_PER_GETN is the maximum number of events to retrieve from port_getn on
- * any particular call. You can speed things up by increasing this, but it will
- * (obviously) require more memory.
- */
- #define EVENTS_PER_GETN 8
- /*
- * Per-file-descriptor information about what events we're subscribed to. These
- * fields are NULL if no event is subscribed to either of them.
- */
- struct fd_info {
- short fdi_what; /* combinations of EV_READ and EV_WRITE */
- };
- #define FDI_HAS_READ(fdi) ((fdi)->fdi_what & EV_READ)
- #define FDI_HAS_WRITE(fdi) ((fdi)->fdi_what & EV_WRITE)
- #define FDI_HAS_EVENTS(fdi) (FDI_HAS_READ(fdi) || FDI_HAS_WRITE(fdi))
- #define FDI_TO_SYSEVENTS(fdi) (FDI_HAS_READ(fdi) ? POLLIN : 0) | \
- (FDI_HAS_WRITE(fdi) ? POLLOUT : 0)
- struct evport_data {
- int ed_port; /* event port for system events */
- int ed_nevents; /* number of allocated fdi's */
- struct fd_info *ed_fds; /* allocated fdi table */
- /* fdi's that we need to reassoc */
- int ed_pending[EVENTS_PER_GETN]; /* fd's with pending events */
- };
- static void* evport_init(struct event_base *);
- static int evport_add(struct event_base *, int fd, short old, short events, void *);
- static int evport_del(struct event_base *, int fd, short old, short events, void *);
- static int evport_dispatch(struct event_base *, struct timeval *);
- static void evport_dealloc(struct event_base *);
- const struct eventop evportops = {
- "evport",
- evport_init,
- evport_add,
- evport_del,
- evport_dispatch,
- evport_dealloc,
- 1, /* need reinit */
- 0, /* features */
- 0, /* fdinfo length */
- };
- /*
- * Initialize the event port implementation.
- */
- static void*
- evport_init(struct event_base *base)
- {
- struct evport_data *evpd;
- int i;
- if (!(evpd = mm_calloc(1, sizeof(struct evport_data))))
- return (NULL);
- if ((evpd->ed_port = port_create()) == -1) {
- mm_free(evpd);
- return (NULL);
- }
- /*
- * Initialize file descriptor structure
- */
- evpd->ed_fds = mm_calloc(DEFAULT_NFDS, sizeof(struct fd_info));
- if (evpd->ed_fds == NULL) {
- close(evpd->ed_port);
- mm_free(evpd);
- return (NULL);
- }
- evpd->ed_nevents = DEFAULT_NFDS;
- for (i = 0; i < EVENTS_PER_GETN; i++)
- evpd->ed_pending[i] = -1;
- evsig_init(base);
- return (evpd);
- }
- #ifdef CHECK_INVARIANTS
- /*
- * Checks some basic properties about the evport_data structure. Because it
- * checks all file descriptors, this function can be expensive when the maximum
- * file descriptor ever used is rather large.
- */
- static void
- check_evportop(struct evport_data *evpd)
- {
- EVUTIL_ASSERT(evpd);
- EVUTIL_ASSERT(evpd->ed_nevents > 0);
- EVUTIL_ASSERT(evpd->ed_port > 0);
- EVUTIL_ASSERT(evpd->ed_fds > 0);
- }
- /*
- * Verifies very basic integrity of a given port_event.
- */
- static void
- check_event(port_event_t* pevt)
- {
- /*
- * We've only registered for PORT_SOURCE_FD events. The only
- * other thing we can legitimately receive is PORT_SOURCE_ALERT,
- * but since we're not using port_alert either, we can assume
- * PORT_SOURCE_FD.
- */
- EVUTIL_ASSERT(pevt->portev_source == PORT_SOURCE_FD);
- EVUTIL_ASSERT(pevt->portev_user == NULL);
- }
- #else
- #define check_evportop(epop)
- #define check_event(pevt)
- #endif /* CHECK_INVARIANTS */
- /*
- * Doubles the size of the allocated file descriptor array.
- */
- static int
- grow(struct evport_data *epdp, int factor)
- {
- struct fd_info *tmp;
- int oldsize = epdp->ed_nevents;
- int newsize = factor * oldsize;
- EVUTIL_ASSERT(factor > 1);
- check_evportop(epdp);
- tmp = mm_realloc(epdp->ed_fds, sizeof(struct fd_info) * newsize);
- if (NULL == tmp)
- return -1;
- epdp->ed_fds = tmp;
- memset((char*) (epdp->ed_fds + oldsize), 0,
- (newsize - oldsize)*sizeof(struct fd_info));
- epdp->ed_nevents = newsize;
- check_evportop(epdp);
- return 0;
- }
- /*
- * (Re)associates the given file descriptor with the event port. The OS events
- * are specified (implicitly) from the fd_info struct.
- */
- static int
- reassociate(struct evport_data *epdp, struct fd_info *fdip, int fd)
- {
- int sysevents = FDI_TO_SYSEVENTS(fdip);
- if (sysevents != 0) {
- if (port_associate(epdp->ed_port, PORT_SOURCE_FD,
- fd, sysevents, NULL) == -1) {
- event_warn("port_associate");
- return (-1);
- }
- }
- check_evportop(epdp);
- return (0);
- }
- /*
- * Main event loop - polls port_getn for some number of events, and processes
- * them.
- */
- static int
- evport_dispatch(struct event_base *base, struct timeval *tv)
- {
- int i, res;
- struct evport_data *epdp = base->evbase;
- port_event_t pevtlist[EVENTS_PER_GETN];
- /*
- * port_getn will block until it has at least nevents events. It will
- * also return how many it's given us (which may be more than we asked
- * for, as long as it's less than our maximum (EVENTS_PER_GETN)) in
- * nevents.
- */
- int nevents = 1;
- /*
- * We have to convert a struct timeval to a struct timespec
- * (only difference is nanoseconds vs. microseconds). If no time-based
- * events are active, we should wait for I/O (and tv == NULL).
- */
- struct timespec ts;
- struct timespec *ts_p = NULL;
- if (tv != NULL) {
- ts.tv_sec = tv->tv_sec;
- ts.tv_nsec = tv->tv_usec * 1000;
- ts_p = &ts;
- }
- /*
- * Before doing anything else, we need to reassociate the events we hit
- * last time which need reassociation. See comment at the end of the
- * loop below.
- */
- for (i = 0; i < EVENTS_PER_GETN; ++i) {
- struct fd_info *fdi = NULL;
- if (epdp->ed_pending[i] != -1) {
- fdi = &(epdp->ed_fds[epdp->ed_pending[i]]);
- }
- if (fdi != NULL && FDI_HAS_EVENTS(fdi)) {
- int fd = epdp->ed_pending[i];
- reassociate(epdp, fdi, fd);
- epdp->ed_pending[i] = -1;
- }
- }
- EVBASE_RELEASE_LOCK(base, th_base_lock);
- res = port_getn(epdp->ed_port, pevtlist, EVENTS_PER_GETN,
- (unsigned int *) &nevents, ts_p);
- EVBASE_ACQUIRE_LOCK(base, th_base_lock);
- if (res == -1) {
- if (errno == EINTR || errno == EAGAIN) {
- return (0);
- } else if (errno == ETIME) {
- if (nevents == 0)
- return (0);
- } else {
- event_warn("port_getn");
- return (-1);
- }
- }
- event_debug(("%s: port_getn reports %d events", __func__, nevents));
- for (i = 0; i < nevents; ++i) {
- struct fd_info *fdi;
- port_event_t *pevt = &pevtlist[i];
- int fd = (int) pevt->portev_object;
- check_evportop(epdp);
- check_event(pevt);
- epdp->ed_pending[i] = fd;
- /*
- * Figure out what kind of event it was
- * (because we have to pass this to the callback)
- */
- res = 0;
- if (pevt->portev_events & (POLLERR|POLLHUP)) {
- res = EV_READ | EV_WRITE;
- } else {
- if (pevt->portev_events & POLLIN)
- res |= EV_READ;
- if (pevt->portev_events & POLLOUT)
- res |= EV_WRITE;
- }
- /*
- * Check for the error situations or a hangup situation
- */
- if (pevt->portev_events & (POLLERR|POLLHUP|POLLNVAL))
- res |= EV_READ|EV_WRITE;
- EVUTIL_ASSERT(epdp->ed_nevents > fd);
- fdi = &(epdp->ed_fds[fd]);
- evmap_io_active(base, fd, res);
- } /* end of all events gotten */
- check_evportop(epdp);
- return (0);
- }
- /*
- * Adds the given event (so that you will be notified when it happens via
- * the callback function).
- */
- static int
- evport_add(struct event_base *base, int fd, short old, short events, void *p)
- {
- struct evport_data *evpd = base->evbase;
- struct fd_info *fdi;
- int factor;
- (void)p;
- check_evportop(evpd);
- /*
- * If necessary, grow the file descriptor info table
- */
- factor = 1;
- while (fd >= factor * evpd->ed_nevents)
- factor *= 2;
- if (factor > 1) {
- if (-1 == grow(evpd, factor)) {
- return (-1);
- }
- }
- fdi = &evpd->ed_fds[fd];
- fdi->fdi_what |= events;
- return reassociate(evpd, fdi, fd);
- }
- /*
- * Removes the given event from the list of events to wait for.
- */
- static int
- evport_del(struct event_base *base, int fd, short old, short events, void *p)
- {
- struct evport_data *evpd = base->evbase;
- struct fd_info *fdi;
- int i;
- int associated = 1;
- (void)p;
- check_evportop(evpd);
- if (evpd->ed_nevents < fd) {
- return (-1);
- }
- for (i = 0; i < EVENTS_PER_GETN; ++i) {
- if (evpd->ed_pending[i] == fd) {
- associated = 0;
- break;
- }
- }
- fdi = &evpd->ed_fds[fd];
- if (events & EV_READ)
- fdi->fdi_what &= ~EV_READ;
- if (events & EV_WRITE)
- fdi->fdi_what &= ~EV_WRITE;
- if (associated) {
- if (!FDI_HAS_EVENTS(fdi) &&
- port_dissociate(evpd->ed_port, PORT_SOURCE_FD, fd) == -1) {
- /*
- * Ignore EBADFD error the fd could have been closed
- * before event_del() was called.
- */
- if (errno != EBADFD) {
- event_warn("port_dissociate");
- return (-1);
- }
- } else {
- if (FDI_HAS_EVENTS(fdi)) {
- return (reassociate(evpd, fdi, fd));
- }
- }
- } else {
- if ((fdi->fdi_what & (EV_READ|EV_WRITE)) == 0) {
- evpd->ed_pending[i] = -1;
- }
- }
- return 0;
- }
- static void
- evport_dealloc(struct event_base *base)
- {
- struct evport_data *evpd = base->evbase;
- evsig_dealloc(base);
- close(evpd->ed_port);
- if (evpd->ed_fds)
- mm_free(evpd->ed_fds);
- mm_free(evpd);
- }