1 /*
2 * Copyright 2000-2009 Niels Provos <provos@citi.umich.edu>
3 * Copyright 2009-2012 Niels Provos and Nick Mathewson
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27 #include "event2/event-config.h"
28
29 #include <sys/types.h>
30 #include <sys/resource.h>
31 #ifdef _EVENT_HAVE_SYS_TIME_H
32 #include <sys/time.h>
33 #endif
34 #include <sys/queue.h>
35 #include <sys/devpoll.h>
36 #include <signal.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <unistd.h>
41 #include <fcntl.h>
42 #include <errno.h>
43
44 #include "event2/event.h"
45 #include "event2/event_struct.h"
46 #include "event2/thread.h"
47 #include "event-internal.h"
48 #include "evsignal-internal.h"
49 #include "log-internal.h"
50 #include "evmap-internal.h"
51 #include "evthread-internal.h"
52
53 struct devpollop {
54 struct pollfd *events;
55 int nevents;
56 int dpfd;
57 struct pollfd *changes;
58 int nchanges;
59 };
60
61 static void *devpoll_init(struct event_base *);
62 static int devpoll_add(struct event_base *, int fd, short old, short events, void *);
63 static int devpoll_del(struct event_base *, int fd, short old, short events, void *);
64 static int devpoll_dispatch(struct event_base *, struct timeval *);
65 static void devpoll_dealloc(struct event_base *);
66
67 const struct eventop devpollops = {
68 "devpoll",
69 devpoll_init,
70 devpoll_add,
71 devpoll_del,
72 devpoll_dispatch,
73 devpoll_dealloc,
74 1, /* need reinit */
75 EV_FEATURE_FDS|EV_FEATURE_O1,
76 0
77 };
78
79 #define NEVENT 32000
80
81 static int
devpoll_commit(struct devpollop * devpollop)82 devpoll_commit(struct devpollop *devpollop)
83 {
84 /*
85 * Due to a bug in Solaris, we have to use pwrite with an offset of 0.
86 * Write is limited to 2GB of data, until it will fail.
87 */
88 if (pwrite(devpollop->dpfd, devpollop->changes,
89 sizeof(struct pollfd) * devpollop->nchanges, 0) == -1)
90 return (-1);
91
92 devpollop->nchanges = 0;
93 return (0);
94 }
95
96 static int
devpoll_queue(struct devpollop * devpollop,int fd,int events)97 devpoll_queue(struct devpollop *devpollop, int fd, int events) {
98 struct pollfd *pfd;
99
100 if (devpollop->nchanges >= devpollop->nevents) {
101 /*
102 * Change buffer is full, must commit it to /dev/poll before
103 * adding more
104 */
105 if (devpoll_commit(devpollop) != 0)
106 return (-1);
107 }
108
109 pfd = &devpollop->changes[devpollop->nchanges++];
110 pfd->fd = fd;
111 pfd->events = events;
112 pfd->revents = 0;
113
114 return (0);
115 }
116
117 static void *
devpoll_init(struct event_base * base)118 devpoll_init(struct event_base *base)
119 {
120 int dpfd, nfiles = NEVENT;
121 struct rlimit rl;
122 struct devpollop *devpollop;
123
124 if (!(devpollop = mm_calloc(1, sizeof(struct devpollop))))
125 return (NULL);
126
127 if (getrlimit(RLIMIT_NOFILE, &rl) == 0 &&
128 rl.rlim_cur != RLIM_INFINITY)
129 nfiles = rl.rlim_cur;
130
131 /* Initialize the kernel queue */
132 if ((dpfd = evutil_open_closeonexec("/dev/poll", O_RDWR, 0)) == -1) {
133 event_warn("open: /dev/poll");
134 mm_free(devpollop);
135 return (NULL);
136 }
137
138 devpollop->dpfd = dpfd;
139
140 /* Initialize fields */
141 /* FIXME: allocating 'nfiles' worth of space here can be
142 * expensive and unnecessary. See how epoll.c does it instead. */
143 devpollop->events = mm_calloc(nfiles, sizeof(struct pollfd));
144 if (devpollop->events == NULL) {
145 mm_free(devpollop);
146 close(dpfd);
147 return (NULL);
148 }
149 devpollop->nevents = nfiles;
150
151 devpollop->changes = mm_calloc(nfiles, sizeof(struct pollfd));
152 if (devpollop->changes == NULL) {
153 mm_free(devpollop->events);
154 mm_free(devpollop);
155 close(dpfd);
156 return (NULL);
157 }
158
159 evsig_init(base);
160
161 return (devpollop);
162 }
163
164 static int
devpoll_dispatch(struct event_base * base,struct timeval * tv)165 devpoll_dispatch(struct event_base *base, struct timeval *tv)
166 {
167 struct devpollop *devpollop = base->evbase;
168 struct pollfd *events = devpollop->events;
169 struct dvpoll dvp;
170 int i, res, timeout = -1;
171
172 if (devpollop->nchanges)
173 devpoll_commit(devpollop);
174
175 if (tv != NULL)
176 timeout = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000;
177
178 dvp.dp_fds = devpollop->events;
179 dvp.dp_nfds = devpollop->nevents;
180 dvp.dp_timeout = timeout;
181
182 EVBASE_RELEASE_LOCK(base, th_base_lock);
183
184 res = ioctl(devpollop->dpfd, DP_POLL, &dvp);
185
186 EVBASE_ACQUIRE_LOCK(base, th_base_lock);
187
188 if (res == -1) {
189 if (errno != EINTR) {
190 event_warn("ioctl: DP_POLL");
191 return (-1);
192 }
193
194 return (0);
195 }
196
197 event_debug(("%s: devpoll_wait reports %d", __func__, res));
198
199 for (i = 0; i < res; i++) {
200 int which = 0;
201 int what = events[i].revents;
202
203 if (what & POLLHUP)
204 what |= POLLIN | POLLOUT;
205 else if (what & POLLERR)
206 what |= POLLIN | POLLOUT;
207
208 if (what & POLLIN)
209 which |= EV_READ;
210 if (what & POLLOUT)
211 which |= EV_WRITE;
212
213 if (!which)
214 continue;
215
216 /* XXX(niels): not sure if this works for devpoll */
217 evmap_io_active(base, events[i].fd, which);
218 }
219
220 return (0);
221 }
222
223
224 static int
devpoll_add(struct event_base * base,int fd,short old,short events,void * p)225 devpoll_add(struct event_base *base, int fd, short old, short events, void *p)
226 {
227 struct devpollop *devpollop = base->evbase;
228 int res;
229 (void)p;
230
231 /*
232 * It's not necessary to OR the existing read/write events that we
233 * are currently interested in with the new event we are adding.
234 * The /dev/poll driver ORs any new events with the existing events
235 * that it has cached for the fd.
236 */
237
238 res = 0;
239 if (events & EV_READ)
240 res |= POLLIN;
241 if (events & EV_WRITE)
242 res |= POLLOUT;
243
244 if (devpoll_queue(devpollop, fd, res) != 0)
245 return (-1);
246
247 return (0);
248 }
249
250 static int
devpoll_del(struct event_base * base,int fd,short old,short events,void * p)251 devpoll_del(struct event_base *base, int fd, short old, short events, void *p)
252 {
253 struct devpollop *devpollop = base->evbase;
254 int res;
255 (void)p;
256
257 res = 0;
258 if (events & EV_READ)
259 res |= POLLIN;
260 if (events & EV_WRITE)
261 res |= POLLOUT;
262
263 /*
264 * The only way to remove an fd from the /dev/poll monitored set is
265 * to use POLLREMOVE by itself. This removes ALL events for the fd
266 * provided so if we care about two events and are only removing one
267 * we must re-add the other event after POLLREMOVE.
268 */
269
270 if (devpoll_queue(devpollop, fd, POLLREMOVE) != 0)
271 return (-1);
272
273 if ((res & (POLLIN|POLLOUT)) != (POLLIN|POLLOUT)) {
274 /*
275 * We're not deleting all events, so we must resubmit the
276 * event that we are still interested in if one exists.
277 */
278
279 if ((res & POLLIN) && (old & EV_WRITE)) {
280 /* Deleting read, still care about write */
281 devpoll_queue(devpollop, fd, POLLOUT);
282 } else if ((res & POLLOUT) && (old & EV_READ)) {
283 /* Deleting write, still care about read */
284 devpoll_queue(devpollop, fd, POLLIN);
285 }
286 }
287
288 return (0);
289 }
290
291 static void
devpoll_dealloc(struct event_base * base)292 devpoll_dealloc(struct event_base *base)
293 {
294 struct devpollop *devpollop = base->evbase;
295
296 evsig_dealloc(base);
297 if (devpollop->events)
298 mm_free(devpollop->events);
299 if (devpollop->changes)
300 mm_free(devpollop->changes);
301 if (devpollop->dpfd >= 0)
302 close(devpollop->dpfd);
303
304 memset(devpollop, 0, sizeof(struct devpollop));
305 mm_free(devpollop);
306 }
307