/*
* 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);
}