1 /* $OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
2
3 /*
4 * Copyright 2000-2002 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 <signal.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include <errno.h>
47 #ifdef CHECK_INVARIANTS
48 #include <assert.h>
49 #endif
50
51 #include "event.h"
52 #include "event-internal.h"
53 #include "evsignal.h"
54 #include "log.h"
55
56 #ifndef howmany
57 #define howmany(x, y) (((x)+((y)-1))/(y))
58 #endif
59
60 extern volatile sig_atomic_t evsignal_caught;
61
62 struct selectop {
63 int event_fds; /* Highest fd in fd set */
64 int event_fdsz;
65 fd_set *event_readset_in;
66 fd_set *event_writeset_in;
67 fd_set *event_readset_out;
68 fd_set *event_writeset_out;
69 struct event **event_r_by_fd;
70 struct event **event_w_by_fd;
71 };
72
73 void *select_init (void);
74 int select_add (void *, struct event *);
75 int select_del (void *, struct event *);
76 int select_recalc (struct event_base *, void *, int);
77 int select_dispatch (struct event_base *, void *, struct timeval *);
78 void select_dealloc (void *);
79
80 const struct eventop selectops = {
81 "select",
82 select_init,
83 select_add,
84 select_del,
85 select_recalc,
86 select_dispatch,
87 select_dealloc
88 };
89
90 static int select_resize(struct selectop *sop, int fdsz);
91
92 void *
select_init(void)93 select_init(void)
94 {
95 struct selectop *sop;
96
97 /* Disable select when this environment variable is set */
98 if (getenv("EVENT_NOSELECT"))
99 return (NULL);
100
101 if (!(sop = calloc(1, sizeof(struct selectop))))
102 return (NULL);
103
104 select_resize(sop, howmany(32 + 1, NFDBITS)*sizeof(fd_mask));
105
106 evsignal_init();
107
108 return (sop);
109 }
110
111 #ifdef CHECK_INVARIANTS
112 static void
check_selectop(struct selectop * sop)113 check_selectop(struct selectop *sop)
114 {
115 int i;
116 for (i=0;i<=sop->event_fds;++i) {
117 if (FD_ISSET(i, sop->event_readset_in)) {
118 assert(sop->event_r_by_fd[i]);
119 assert(sop->event_r_by_fd[i]->ev_events & EV_READ);
120 assert(sop->event_r_by_fd[i]->ev_fd == i);
121 } else {
122 assert(! sop->event_r_by_fd[i]);
123 }
124 if (FD_ISSET(i, sop->event_writeset_in)) {
125 assert(sop->event_w_by_fd[i]);
126 assert(sop->event_w_by_fd[i]->ev_events & EV_WRITE);
127 assert(sop->event_w_by_fd[i]->ev_fd == i);
128 } else {
129 assert(! sop->event_w_by_fd[i]);
130 }
131 }
132
133 }
134 #else
135 #define check_selectop(sop) do { (void) sop; } while (0)
136 #endif
137
138 /*
139 * Called with the highest fd that we know about. If it is 0, completely
140 * recalculate everything.
141 */
142
143 int
select_recalc(struct event_base * base,void * arg,int max)144 select_recalc(struct event_base *base, void *arg, int max)
145 {
146 struct selectop *sop = arg;
147
148 check_selectop(sop);
149
150 return (0);
151 }
152
153 int
select_dispatch(struct event_base * base,void * arg,struct timeval * tv)154 select_dispatch(struct event_base *base, void *arg, struct timeval *tv)
155 {
156 int res, i;
157 struct selectop *sop = arg;
158
159 check_selectop(sop);
160
161 memcpy(sop->event_readset_out, sop->event_readset_in,
162 sop->event_fdsz);
163 memcpy(sop->event_writeset_out, sop->event_writeset_in,
164 sop->event_fdsz);
165
166 res = select(sop->event_fds + 1, sop->event_readset_out,
167 sop->event_writeset_out, NULL, tv);
168
169 check_selectop(sop);
170
171 if (res == -1) {
172 if (errno != EINTR) {
173 event_warn("select");
174 return (-1);
175 }
176
177 evsignal_process();
178 return (0);
179 } else if (evsignal_caught)
180 evsignal_process();
181
182 event_debug(("%s: select reports %d", __func__, res));
183
184 check_selectop(sop);
185 for (i = 0; i <= sop->event_fds; ++i) {
186 struct event *r_ev = NULL, *w_ev = NULL;
187 res = 0;
188 if (FD_ISSET(i, sop->event_readset_out)) {
189 r_ev = sop->event_r_by_fd[i];
190 res |= EV_READ;
191 }
192 if (FD_ISSET(i, sop->event_writeset_out)) {
193 w_ev = sop->event_w_by_fd[i];
194 res |= EV_WRITE;
195 }
196 if (r_ev && (res & r_ev->ev_events)) {
197 if (!(r_ev->ev_events & EV_PERSIST))
198 event_del(r_ev);
199 event_active(r_ev, res & r_ev->ev_events, 1);
200 }
201 if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
202 if (!(w_ev->ev_events & EV_PERSIST))
203 event_del(w_ev);
204 event_active(w_ev, res & w_ev->ev_events, 1);
205 }
206 }
207 check_selectop(sop);
208
209 return (0);
210 }
211
212
213 static int
select_resize(struct selectop * sop,int fdsz)214 select_resize(struct selectop *sop, int fdsz)
215 {
216 int n_events, n_events_old;
217
218 fd_set *readset_in = NULL;
219 fd_set *writeset_in = NULL;
220 fd_set *readset_out = NULL;
221 fd_set *writeset_out = NULL;
222 struct event **r_by_fd = NULL;
223 struct event **w_by_fd = NULL;
224
225 n_events = (fdsz/sizeof(fd_mask)) * NFDBITS;
226 n_events_old = (sop->event_fdsz/sizeof(fd_mask)) * NFDBITS;
227
228 if (sop->event_readset_in)
229 check_selectop(sop);
230
231 if ((readset_in = realloc(sop->event_readset_in, fdsz)) == NULL)
232 goto error;
233 sop->event_readset_in = readset_in;
234 if ((readset_out = realloc(sop->event_readset_out, fdsz)) == NULL)
235 goto error;
236 sop->event_readset_out = readset_out;
237 if ((writeset_in = realloc(sop->event_writeset_in, fdsz)) == NULL)
238 goto error;
239 sop->event_writeset_in = writeset_in;
240 if ((writeset_out = realloc(sop->event_writeset_out, fdsz)) == NULL)
241 goto error;
242 sop->event_writeset_out = writeset_out;
243 if ((r_by_fd = realloc(sop->event_r_by_fd,
244 n_events*sizeof(struct event*))) == NULL)
245 goto error;
246 sop->event_r_by_fd = r_by_fd;
247 if ((w_by_fd = realloc(sop->event_w_by_fd,
248 n_events * sizeof(struct event*))) == NULL)
249 goto error;
250 sop->event_w_by_fd = w_by_fd;
251
252 memset((char *)sop->event_readset_in + sop->event_fdsz, 0,
253 fdsz - sop->event_fdsz);
254 memset((char *)sop->event_writeset_in + sop->event_fdsz, 0,
255 fdsz - sop->event_fdsz);
256 memset(sop->event_r_by_fd + n_events_old, 0,
257 (n_events-n_events_old) * sizeof(struct event*));
258 memset(sop->event_w_by_fd + n_events_old, 0,
259 (n_events-n_events_old) * sizeof(struct event*));
260
261 sop->event_fdsz = fdsz;
262 check_selectop(sop);
263
264 return (0);
265
266 error:
267 event_warn("malloc");
268 return (-1);
269 }
270
271
272 int
select_add(void * arg,struct event * ev)273 select_add(void *arg, struct event *ev)
274 {
275 struct selectop *sop = arg;
276
277 if (ev->ev_events & EV_SIGNAL)
278 return (evsignal_add(ev));
279
280 check_selectop(sop);
281 /*
282 * Keep track of the highest fd, so that we can calculate the size
283 * of the fd_sets for select(2)
284 */
285 if (sop->event_fds < ev->ev_fd) {
286 int fdsz = sop->event_fdsz;
287
288 if (fdsz < sizeof(fd_mask))
289 fdsz = sizeof(fd_mask);
290
291 while (fdsz <
292 (howmany(ev->ev_fd + 1, NFDBITS) * sizeof(fd_mask)))
293 fdsz *= 2;
294
295 if (fdsz != sop->event_fdsz) {
296 if (select_resize(sop, fdsz)) {
297 check_selectop(sop);
298 return (-1);
299 }
300 }
301
302 sop->event_fds = ev->ev_fd;
303 }
304
305 if (ev->ev_events & EV_READ) {
306 FD_SET(ev->ev_fd, sop->event_readset_in);
307 sop->event_r_by_fd[ev->ev_fd] = ev;
308 }
309 if (ev->ev_events & EV_WRITE) {
310 FD_SET(ev->ev_fd, sop->event_writeset_in);
311 sop->event_w_by_fd[ev->ev_fd] = ev;
312 }
313 check_selectop(sop);
314
315 return (0);
316 }
317
318 /*
319 * Nothing to be done here.
320 */
321
322 int
select_del(void * arg,struct event * ev)323 select_del(void *arg, struct event *ev)
324 {
325 struct selectop *sop = arg;
326
327 check_selectop(sop);
328 if (ev->ev_events & EV_SIGNAL)
329 return (evsignal_del(ev));
330
331 if (sop->event_fds < ev->ev_fd) {
332 check_selectop(sop);
333 return (0);
334 }
335
336 if (ev->ev_events & EV_READ) {
337 FD_CLR(ev->ev_fd, sop->event_readset_in);
338 sop->event_r_by_fd[ev->ev_fd] = NULL;
339 }
340
341 if (ev->ev_events & EV_WRITE) {
342 FD_CLR(ev->ev_fd, sop->event_writeset_in);
343 sop->event_w_by_fd[ev->ev_fd] = NULL;
344 }
345
346 check_selectop(sop);
347 return (0);
348 }
349
350 void
select_dealloc(void * arg)351 select_dealloc(void *arg)
352 {
353 struct selectop *sop = arg;
354
355 if (sop->event_readset_in)
356 free(sop->event_readset_in);
357 if (sop->event_writeset_in)
358 free(sop->event_writeset_in);
359 if (sop->event_readset_out)
360 free(sop->event_readset_out);
361 if (sop->event_writeset_out)
362 free(sop->event_writeset_out);
363 if (sop->event_r_by_fd)
364 free(sop->event_r_by_fd);
365 if (sop->event_w_by_fd)
366 free(sop->event_w_by_fd);
367
368 memset(sop, 0, sizeof(struct selectop));
369 free(sop);
370 }
371