1 /* $OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
2
3 /*
4 * Copyright 2000-2003 Niels Provos <provos@citi.umich.edu>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29 #ifdef HAVE_CONFIG_H
30 #include "config.h"
31 #endif
32
33 #include <sys/types.h>
34 #ifdef HAVE_SYS_TIME_H
35 #include <sys/time.h>
36 #else
37 #include <sys/_time.h>
38 #endif
39 #include <sys/queue.h>
40 #include <sys/tree.h>
41 #include <poll.h>
42 #include <signal.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <unistd.h>
47 #include <errno.h>
48 #ifdef CHECK_INVARIANTS
49 #include <assert.h>
50 #endif
51
52 #include "event.h"
53 #include "event-internal.h"
54 #include "evsignal.h"
55 #include "log.h"
56
57 extern volatile sig_atomic_t evsignal_caught;
58
59 struct pollop {
60 int event_count; /* Highest number alloc */
61 int nfds; /* Size of event_* */
62 int fd_count; /* Size of idxplus1_by_fd */
63 struct pollfd *event_set;
64 struct event **event_r_back;
65 struct event **event_w_back;
66 int *idxplus1_by_fd; /* Index into event_set by fd; we add 1 so
67 * that 0 (which is easy to memset) can mean
68 * "no entry." */
69 };
70
71 void *poll_init (void);
72 int poll_add (void *, struct event *);
73 int poll_del (void *, struct event *);
74 int poll_recalc (struct event_base *, void *, int);
75 int poll_dispatch (struct event_base *, void *, struct timeval *);
76 void poll_dealloc (void *);
77
78 const struct eventop pollops = {
79 "poll",
80 poll_init,
81 poll_add,
82 poll_del,
83 poll_recalc,
84 poll_dispatch,
85 poll_dealloc
86 };
87
88 void *
poll_init(void)89 poll_init(void)
90 {
91 struct pollop *pollop;
92
93 /* Disable poll when this environment variable is set */
94 if (getenv("EVENT_NOPOLL"))
95 return (NULL);
96
97 if (!(pollop = calloc(1, sizeof(struct pollop))))
98 return (NULL);
99
100 evsignal_init();
101
102 return (pollop);
103 }
104
105 /*
106 * Called with the highest fd that we know about. If it is 0, completely
107 * recalculate everything.
108 */
109
110 int
poll_recalc(struct event_base * base,void * arg,int max)111 poll_recalc(struct event_base *base, void *arg, int max)
112 {
113 return (0);
114 }
115
116 #ifdef CHECK_INVARIANTS
117 static void
poll_check_ok(struct pollop * pop)118 poll_check_ok(struct pollop *pop)
119 {
120 int i, idx;
121 struct event *ev;
122
123 for (i = 0; i < pop->fd_count; ++i) {
124 idx = pop->idxplus1_by_fd[i]-1;
125 if (idx < 0)
126 continue;
127 assert(pop->event_set[idx].fd == i);
128 if (pop->event_set[idx].events & POLLIN) {
129 ev = pop->event_r_back[idx];
130 assert(ev);
131 assert(ev->ev_events & EV_READ);
132 assert(ev->ev_fd == i);
133 }
134 if (pop->event_set[idx].events & POLLOUT) {
135 ev = pop->event_w_back[idx];
136 assert(ev);
137 assert(ev->ev_events & EV_WRITE);
138 assert(ev->ev_fd == i);
139 }
140 }
141 for (i = 0; i < pop->nfds; ++i) {
142 struct pollfd *pfd = &pop->event_set[i];
143 assert(pop->idxplus1_by_fd[pfd->fd] == i+1);
144 }
145 }
146 #else
147 #define poll_check_ok(pop)
148 #endif
149
150 int
poll_dispatch(struct event_base * base,void * arg,struct timeval * tv)151 poll_dispatch(struct event_base *base, void *arg, struct timeval *tv)
152 {
153 int res, i, sec, nfds;
154 struct pollop *pop = arg;
155
156 poll_check_ok(pop);
157 sec = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000;
158 nfds = pop->nfds;
159 res = poll(pop->event_set, nfds, sec);
160
161 if (res == -1) {
162 if (errno != EINTR) {
163 event_warn("poll");
164 return (-1);
165 }
166
167 evsignal_process();
168 return (0);
169 } else if (evsignal_caught)
170 evsignal_process();
171
172 event_debug(("%s: poll reports %d", __func__, res));
173
174 if (res == 0)
175 return (0);
176
177 for (i = 0; i < nfds; i++) {
178 int what = pop->event_set[i].revents;
179 struct event *r_ev = NULL, *w_ev = NULL;
180 if (!what)
181 continue;
182
183 res = 0;
184
185 /* If the file gets closed notify */
186 if (what & (POLLHUP|POLLERR))
187 what |= POLLIN|POLLOUT;
188 if (what & POLLIN) {
189 res |= EV_READ;
190 r_ev = pop->event_r_back[i];
191 }
192 if (what & POLLOUT) {
193 res |= EV_WRITE;
194 w_ev = pop->event_w_back[i];
195 }
196 if (res == 0)
197 continue;
198
199 if (r_ev && (res & r_ev->ev_events)) {
200 if (!(r_ev->ev_events & EV_PERSIST))
201 event_del(r_ev);
202 event_active(r_ev, res & r_ev->ev_events, 1);
203 }
204 if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
205 if (!(w_ev->ev_events & EV_PERSIST))
206 event_del(w_ev);
207 event_active(w_ev, res & w_ev->ev_events, 1);
208 }
209 }
210
211 return (0);
212 }
213
214 int
poll_add(void * arg,struct event * ev)215 poll_add(void *arg, struct event *ev)
216 {
217 struct pollop *pop = arg;
218 struct pollfd *pfd = NULL;
219 int i;
220
221 if (ev->ev_events & EV_SIGNAL)
222 return (evsignal_add(ev));
223 if (!(ev->ev_events & (EV_READ|EV_WRITE)))
224 return (0);
225
226 poll_check_ok(pop);
227 if (pop->nfds + 1 >= pop->event_count) {
228 struct pollfd *tmp_event_set;
229 struct event **tmp_event_r_back;
230 struct event **tmp_event_w_back;
231 int tmp_event_count;
232
233 if (pop->event_count < 32)
234 tmp_event_count = 32;
235 else
236 tmp_event_count = pop->event_count * 2;
237
238 /* We need more file descriptors */
239 tmp_event_set = realloc(pop->event_set,
240 tmp_event_count * sizeof(struct pollfd));
241 if (tmp_event_set == NULL) {
242 event_warn("realloc");
243 return (-1);
244 }
245 pop->event_set = tmp_event_set;
246
247 tmp_event_r_back = realloc(pop->event_r_back,
248 tmp_event_count * sizeof(struct event *));
249 if (tmp_event_r_back == NULL) {
250 /* event_set overallocated; that's okay. */
251 event_warn("realloc");
252 return (-1);
253 }
254 pop->event_r_back = tmp_event_r_back;
255
256 tmp_event_w_back = realloc(pop->event_w_back,
257 tmp_event_count * sizeof(struct event *));
258 if (tmp_event_w_back == NULL) {
259 /* event_set and event_r_back overallocated; that's
260 * okay. */
261 event_warn("realloc");
262 return (-1);
263 }
264 pop->event_w_back = tmp_event_w_back;
265
266 pop->event_count = tmp_event_count;
267 }
268 if (ev->ev_fd >= pop->fd_count) {
269 int *tmp_idxplus1_by_fd;
270 int new_count;
271 if (pop->fd_count < 32)
272 new_count = 32;
273 else
274 new_count = pop->fd_count * 2;
275 while (new_count <= ev->ev_fd)
276 new_count *= 2;
277 tmp_idxplus1_by_fd =
278 realloc(pop->idxplus1_by_fd, new_count * sizeof(int));
279 if (tmp_idxplus1_by_fd == NULL) {
280 event_warn("realloc");
281 return (-1);
282 }
283 pop->idxplus1_by_fd = tmp_idxplus1_by_fd;
284 memset(pop->idxplus1_by_fd + pop->fd_count,
285 0, sizeof(int)*(new_count - pop->fd_count));
286 pop->fd_count = new_count;
287 }
288
289 i = pop->idxplus1_by_fd[ev->ev_fd] - 1;
290 if (i >= 0) {
291 pfd = &pop->event_set[i];
292 } else {
293 i = pop->nfds++;
294 pfd = &pop->event_set[i];
295 pfd->events = 0;
296 pfd->fd = ev->ev_fd;
297 pop->event_w_back[i] = pop->event_r_back[i] = NULL;
298 pop->idxplus1_by_fd[ev->ev_fd] = i + 1;
299 }
300
301 pfd->revents = 0;
302 if (ev->ev_events & EV_WRITE) {
303 pfd->events |= POLLOUT;
304 pop->event_w_back[i] = ev;
305 }
306 if (ev->ev_events & EV_READ) {
307 pfd->events |= POLLIN;
308 pop->event_r_back[i] = ev;
309 }
310 poll_check_ok(pop);
311
312 return (0);
313 }
314
315 /*
316 * Nothing to be done here.
317 */
318
319 int
poll_del(void * arg,struct event * ev)320 poll_del(void *arg, struct event *ev)
321 {
322 struct pollop *pop = arg;
323 struct pollfd *pfd = NULL;
324 int i;
325
326 if (ev->ev_events & EV_SIGNAL)
327 return (evsignal_del(ev));
328
329 if (!(ev->ev_events & (EV_READ|EV_WRITE)))
330 return (0);
331
332 poll_check_ok(pop);
333 i = pop->idxplus1_by_fd[ev->ev_fd] - 1;
334 if (i < 0)
335 return (-1);
336
337 /* Do we still want to read or write? */
338 pfd = &pop->event_set[i];
339 if (ev->ev_events & EV_READ) {
340 pfd->events &= ~POLLIN;
341 pop->event_r_back[i] = NULL;
342 }
343 if (ev->ev_events & EV_WRITE) {
344 pfd->events &= ~POLLOUT;
345 pop->event_w_back[i] = NULL;
346 }
347 poll_check_ok(pop);
348 if (pfd->events)
349 /* Another event cares about that fd. */
350 return (0);
351
352 /* Okay, so we aren't interested in that fd anymore. */
353 pop->idxplus1_by_fd[ev->ev_fd] = 0;
354
355 --pop->nfds;
356 if (i != pop->nfds) {
357 /*
358 * Shift the last pollfd down into the now-unoccupied
359 * position.
360 */
361 memcpy(&pop->event_set[i], &pop->event_set[pop->nfds],
362 sizeof(struct pollfd));
363 pop->event_r_back[i] = pop->event_r_back[pop->nfds];
364 pop->event_w_back[i] = pop->event_w_back[pop->nfds];
365 pop->idxplus1_by_fd[pop->event_set[i].fd] = i + 1;
366 }
367
368 poll_check_ok(pop);
369 return (0);
370 }
371
372 void
poll_dealloc(void * arg)373 poll_dealloc(void *arg)
374 {
375 struct pollop *pop = arg;
376
377 if (pop->event_set)
378 free(pop->event_set);
379 if (pop->event_r_back)
380 free(pop->event_r_back);
381 if (pop->event_w_back)
382 free(pop->event_w_back);
383 if (pop->idxplus1_by_fd)
384 free(pop->idxplus1_by_fd);
385
386 memset(pop, 0, sizeof(struct pollop));
387 free(pop);
388 }
389