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