1 /* $NetBSD: devpoll.c,v 1.1.1.1 2013/04/11 16:43:24 christos Exp $ */
3 * Copyright 2000-2009 Niels Provos <provos@citi.umich.edu>
4 * Copyright 2009-2012 Niels Provos and Nick Mathewson
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #include "event2/event-config.h"
29 #include <sys/cdefs.h>
30 __RCSID("$NetBSD: devpoll.c,v 1.1.1.1 2013/04/11 16:43:24 christos Exp $");
32 #include <sys/types.h>
33 #include <sys/resource.h>
34 #ifdef _EVENT_HAVE_SYS_TIME_H
37 #include <sys/queue.h>
38 #include <sys/devpoll.h>
47 #include "event2/event.h"
48 #include "event2/event_struct.h"
49 #include "event2/thread.h"
50 #include "event-internal.h"
51 #include "evsignal-internal.h"
52 #include "log-internal.h"
53 #include "evmap-internal.h"
54 #include "evthread-internal.h"
57 struct pollfd
*events
;
60 struct pollfd
*changes
;
64 static void *devpoll_init(struct event_base
*);
65 static int devpoll_add(struct event_base
*, int fd
, short old
, short events
, void *);
66 static int devpoll_del(struct event_base
*, int fd
, short old
, short events
, void *);
67 static int devpoll_dispatch(struct event_base
*, struct timeval
*);
68 static void devpoll_dealloc(struct event_base
*);
70 const struct eventop devpollops
= {
78 EV_FEATURE_FDS
|EV_FEATURE_O1
,
85 devpoll_commit(struct devpollop
*devpollop
)
88 * Due to a bug in Solaris, we have to use pwrite with an offset of 0.
89 * Write is limited to 2GB of data, until it will fail.
91 if (pwrite(devpollop
->dpfd
, devpollop
->changes
,
92 sizeof(struct pollfd
) * devpollop
->nchanges
, 0) == -1)
95 devpollop
->nchanges
= 0;
100 devpoll_queue(struct devpollop
*devpollop
, int fd
, int events
) {
103 if (devpollop
->nchanges
>= devpollop
->nevents
) {
105 * Change buffer is full, must commit it to /dev/poll before
108 if (devpoll_commit(devpollop
) != 0)
112 pfd
= &devpollop
->changes
[devpollop
->nchanges
++];
114 pfd
->events
= events
;
121 devpoll_init(struct event_base
*base
)
123 int dpfd
, nfiles
= NEVENT
;
125 struct devpollop
*devpollop
;
127 if (!(devpollop
= mm_calloc(1, sizeof(struct devpollop
))))
130 if (getrlimit(RLIMIT_NOFILE
, &rl
) == 0 &&
131 rl
.rlim_cur
!= RLIM_INFINITY
)
132 nfiles
= rl
.rlim_cur
;
134 /* Initialize the kernel queue */
135 if ((dpfd
= evutil_open_closeonexec("/dev/poll", O_RDWR
, 0)) == -1) {
136 event_warn("open: /dev/poll");
141 devpollop
->dpfd
= dpfd
;
143 /* Initialize fields */
144 /* FIXME: allocating 'nfiles' worth of space here can be
145 * expensive and unnecessary. See how epoll.c does it instead. */
146 devpollop
->events
= mm_calloc(nfiles
, sizeof(struct pollfd
));
147 if (devpollop
->events
== NULL
) {
152 devpollop
->nevents
= nfiles
;
154 devpollop
->changes
= mm_calloc(nfiles
, sizeof(struct pollfd
));
155 if (devpollop
->changes
== NULL
) {
156 mm_free(devpollop
->events
);
168 devpoll_dispatch(struct event_base
*base
, struct timeval
*tv
)
170 struct devpollop
*devpollop
= base
->evbase
;
171 struct pollfd
*events
= devpollop
->events
;
173 int i
, res
, timeout
= -1;
175 if (devpollop
->nchanges
)
176 devpoll_commit(devpollop
);
179 timeout
= tv
->tv_sec
* 1000 + (tv
->tv_usec
+ 999) / 1000;
181 dvp
.dp_fds
= devpollop
->events
;
182 dvp
.dp_nfds
= devpollop
->nevents
;
183 dvp
.dp_timeout
= timeout
;
185 EVBASE_RELEASE_LOCK(base
, th_base_lock
);
187 res
= ioctl(devpollop
->dpfd
, DP_POLL
, &dvp
);
189 EVBASE_ACQUIRE_LOCK(base
, th_base_lock
);
192 if (errno
!= EINTR
) {
193 event_warn("ioctl: DP_POLL");
200 event_debug(("%s: devpoll_wait reports %d", __func__
, res
));
202 for (i
= 0; i
< res
; i
++) {
204 int what
= events
[i
].revents
;
207 what
|= POLLIN
| POLLOUT
;
208 else if (what
& POLLERR
)
209 what
|= POLLIN
| POLLOUT
;
219 /* XXX(niels): not sure if this works for devpoll */
220 evmap_io_active(base
, events
[i
].fd
, which
);
228 devpoll_add(struct event_base
*base
, int fd
, short old
, short events
, void *p
)
230 struct devpollop
*devpollop
= base
->evbase
;
235 * It's not necessary to OR the existing read/write events that we
236 * are currently interested in with the new event we are adding.
237 * The /dev/poll driver ORs any new events with the existing events
238 * that it has cached for the fd.
242 if (events
& EV_READ
)
244 if (events
& EV_WRITE
)
247 if (devpoll_queue(devpollop
, fd
, res
) != 0)
254 devpoll_del(struct event_base
*base
, int fd
, short old
, short events
, void *p
)
256 struct devpollop
*devpollop
= base
->evbase
;
261 if (events
& EV_READ
)
263 if (events
& EV_WRITE
)
267 * The only way to remove an fd from the /dev/poll monitored set is
268 * to use POLLREMOVE by itself. This removes ALL events for the fd
269 * provided so if we care about two events and are only removing one
270 * we must re-add the other event after POLLREMOVE.
273 if (devpoll_queue(devpollop
, fd
, POLLREMOVE
) != 0)
276 if ((res
& (POLLIN
|POLLOUT
)) != (POLLIN
|POLLOUT
)) {
278 * We're not deleting all events, so we must resubmit the
279 * event that we are still interested in if one exists.
282 if ((res
& POLLIN
) && (old
& EV_WRITE
)) {
283 /* Deleting read, still care about write */
284 devpoll_queue(devpollop
, fd
, POLLOUT
);
285 } else if ((res
& POLLOUT
) && (old
& EV_READ
)) {
286 /* Deleting write, still care about read */
287 devpoll_queue(devpollop
, fd
, POLLIN
);
295 devpoll_dealloc(struct event_base
*base
)
297 struct devpollop
*devpollop
= base
->evbase
;
300 if (devpollop
->events
)
301 mm_free(devpollop
->events
);
302 if (devpollop
->changes
)
303 mm_free(devpollop
->changes
);
304 if (devpollop
->dpfd
>= 0)
305 close(devpollop
->dpfd
);
307 memset(devpollop
, 0, sizeof(struct devpollop
));