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/cvs/libev/ev_select.c
Revision: 1.58
Committed: Sat Aug 17 05:30:16 2019 UTC (4 years, 10 months ago) by root
Content type: text/plain
Branch: MAIN
CVS Tags: EV-rel-4_28, EV-rel-4_29, rel-4_33, EV-rel-4_31, EV-rel-4_30, rel-4_31, HEAD
Changes since 1.57: +2 -2 lines
Log Message:
*** empty log message ***

File Contents

# Content
1 /*
2 * libev select fd activity backend
3 *
4 * Copyright (c) 2007,2008,2009,2010,2011 Marc Alexander Lehmann <libev@schmorp.de>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without modifica-
8 * tion, are permitted provided that the following conditions are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
21 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
25 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26 * OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Alternatively, the contents of this file may be used under the terms of
29 * the GNU General Public License ("GPL") version 2 or any later version,
30 * in which case the provisions of the GPL are applicable instead of
31 * the above. If you wish to allow the use of your version of this file
32 * only under the terms of the GPL and not to allow others to use your
33 * version of this file under the BSD license, indicate your decision
34 * by deleting the provisions above and replace them with the notice
35 * and other provisions required by the GPL. If you do not delete the
36 * provisions above, a recipient may use your version of this file under
37 * either the BSD or the GPL.
38 */
39
40 #ifndef _WIN32
41 /* for unix systems */
42 # include <inttypes.h>
43 # ifndef __hpux
44 /* for REAL unix systems */
45 # include <sys/select.h>
46 # endif
47 #endif
48
49 #ifndef EV_SELECT_USE_FD_SET
50 # ifdef NFDBITS
51 # define EV_SELECT_USE_FD_SET 0
52 # else
53 # define EV_SELECT_USE_FD_SET 1
54 # endif
55 #endif
56
57 #if EV_SELECT_IS_WINSOCKET
58 # undef EV_SELECT_USE_FD_SET
59 # define EV_SELECT_USE_FD_SET 1
60 # undef NFDBITS
61 # define NFDBITS 0
62 #endif
63
64 #if !EV_SELECT_USE_FD_SET
65 # define NFDBYTES (NFDBITS / 8)
66 #endif
67
68 #include <string.h>
69
70 static void
71 select_modify (EV_P_ int fd, int oev, int nev)
72 {
73 if (oev == nev)
74 return;
75
76 {
77 #if EV_SELECT_USE_FD_SET
78
79 #if EV_SELECT_IS_WINSOCKET
80 SOCKET handle = anfds [fd].handle;
81 #else
82 int handle = fd;
83 #endif
84
85 assert (("libev: fd >= FD_SETSIZE passed to fd_set-based select backend", fd < FD_SETSIZE));
86
87 /* FD_SET is broken on windows (it adds the fd to a set twice or more,
88 * which eventually leads to overflows). Need to call it only on changes.
89 */
90 #if EV_SELECT_IS_WINSOCKET
91 if ((oev ^ nev) & EV_READ)
92 #endif
93 if (nev & EV_READ)
94 FD_SET (handle, (fd_set *)vec_ri);
95 else
96 FD_CLR (handle, (fd_set *)vec_ri);
97
98 #if EV_SELECT_IS_WINSOCKET
99 if ((oev ^ nev) & EV_WRITE)
100 #endif
101 if (nev & EV_WRITE)
102 FD_SET (handle, (fd_set *)vec_wi);
103 else
104 FD_CLR (handle, (fd_set *)vec_wi);
105
106 #else
107
108 int word = fd / NFDBITS;
109 fd_mask mask = 1UL << (fd % NFDBITS);
110
111 if (ecb_expect_false (vec_max <= word))
112 {
113 int new_max = word + 1;
114
115 vec_ri = ev_realloc (vec_ri, new_max * NFDBYTES);
116 vec_ro = ev_realloc (vec_ro, new_max * NFDBYTES); /* could free/malloc */
117 vec_wi = ev_realloc (vec_wi, new_max * NFDBYTES);
118 vec_wo = ev_realloc (vec_wo, new_max * NFDBYTES); /* could free/malloc */
119 #ifdef _WIN32
120 vec_eo = ev_realloc (vec_eo, new_max * NFDBYTES); /* could free/malloc */
121 #endif
122
123 for (; vec_max < new_max; ++vec_max)
124 ((fd_mask *)vec_ri) [vec_max] =
125 ((fd_mask *)vec_wi) [vec_max] = 0;
126 }
127
128 ((fd_mask *)vec_ri) [word] |= mask;
129 if (!(nev & EV_READ))
130 ((fd_mask *)vec_ri) [word] &= ~mask;
131
132 ((fd_mask *)vec_wi) [word] |= mask;
133 if (!(nev & EV_WRITE))
134 ((fd_mask *)vec_wi) [word] &= ~mask;
135 #endif
136 }
137 }
138
139 static void
140 select_poll (EV_P_ ev_tstamp timeout)
141 {
142 struct timeval tv;
143 int res;
144 int fd_setsize;
145
146 EV_RELEASE_CB;
147 EV_TV_SET (tv, timeout);
148
149 #if EV_SELECT_USE_FD_SET
150 fd_setsize = sizeof (fd_set);
151 #else
152 fd_setsize = vec_max * NFDBYTES;
153 #endif
154
155 memcpy (vec_ro, vec_ri, fd_setsize);
156 memcpy (vec_wo, vec_wi, fd_setsize);
157
158 #ifdef _WIN32
159 /* pass in the write set as except set.
160 * the idea behind this is to work around a windows bug that causes
161 * errors to be reported as an exception and not by setting
162 * the writable bit. this is so uncontrollably lame.
163 */
164 memcpy (vec_eo, vec_wi, fd_setsize);
165 res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, (fd_set *)vec_eo, &tv);
166 #elif EV_SELECT_USE_FD_SET
167 fd_setsize = anfdmax < FD_SETSIZE ? anfdmax : FD_SETSIZE;
168 res = select (fd_setsize, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
169 #else
170 res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
171 #endif
172 EV_ACQUIRE_CB;
173
174 if (ecb_expect_false (res < 0))
175 {
176 #if EV_SELECT_IS_WINSOCKET
177 errno = WSAGetLastError ();
178 #endif
179 #ifdef WSABASEERR
180 /* on windows, select returns incompatible error codes, fix this */
181 if (errno >= WSABASEERR && errno < WSABASEERR + 1000)
182 if (errno == WSAENOTSOCK)
183 errno = EBADF;
184 else
185 errno -= WSABASEERR;
186 #endif
187
188 #ifdef _WIN32
189 /* select on windows erroneously returns EINVAL when no fd sets have been
190 * provided (this is documented). what microsoft doesn't tell you that this bug
191 * exists even when the fd sets _are_ provided, so we have to check for this bug
192 * here and emulate by sleeping manually.
193 * we also get EINVAL when the timeout is invalid, but we ignore this case here
194 * and assume that EINVAL always means: you have to wait manually.
195 */
196 if (errno == EINVAL)
197 {
198 if (timeout)
199 {
200 unsigned long ms = EV_TS_TO_MSEC (timeout);
201 Sleep (ms ? ms : 1);
202 }
203
204 return;
205 }
206 #endif
207
208 if (errno == EBADF)
209 fd_ebadf (EV_A);
210 else if (errno == ENOMEM && !syserr_cb)
211 fd_enomem (EV_A);
212 else if (errno != EINTR)
213 ev_syserr ("(libev) select");
214
215 return;
216 }
217
218 #if EV_SELECT_USE_FD_SET
219
220 {
221 int fd;
222
223 for (fd = 0; fd < anfdmax; ++fd)
224 if (anfds [fd].events)
225 {
226 int events = 0;
227 #if EV_SELECT_IS_WINSOCKET
228 SOCKET handle = anfds [fd].handle;
229 #else
230 int handle = fd;
231 #endif
232
233 if (FD_ISSET (handle, (fd_set *)vec_ro)) events |= EV_READ;
234 if (FD_ISSET (handle, (fd_set *)vec_wo)) events |= EV_WRITE;
235 #ifdef _WIN32
236 if (FD_ISSET (handle, (fd_set *)vec_eo)) events |= EV_WRITE;
237 #endif
238
239 if (ecb_expect_true (events))
240 fd_event (EV_A_ fd, events);
241 }
242 }
243
244 #else
245
246 {
247 int word, bit;
248 for (word = vec_max; word--; )
249 {
250 fd_mask word_r = ((fd_mask *)vec_ro) [word];
251 fd_mask word_w = ((fd_mask *)vec_wo) [word];
252 #ifdef _WIN32
253 word_w |= ((fd_mask *)vec_eo) [word];
254 #endif
255
256 if (word_r || word_w)
257 for (bit = NFDBITS; bit--; )
258 {
259 fd_mask mask = 1UL << bit;
260 int events = 0;
261
262 events |= word_r & mask ? EV_READ : 0;
263 events |= word_w & mask ? EV_WRITE : 0;
264
265 if (ecb_expect_true (events))
266 fd_event (EV_A_ word * NFDBITS + bit, events);
267 }
268 }
269 }
270
271 #endif
272 }
273
274 inline_size
275 int
276 select_init (EV_P_ int flags)
277 {
278 backend_mintime = EV_TS_CONST (1e-6);
279 backend_modify = select_modify;
280 backend_poll = select_poll;
281
282 #if EV_SELECT_USE_FD_SET
283 vec_ri = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_ri);
284 vec_ro = ev_malloc (sizeof (fd_set));
285 vec_wi = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_wi);
286 vec_wo = ev_malloc (sizeof (fd_set));
287 #ifdef _WIN32
288 vec_eo = ev_malloc (sizeof (fd_set));
289 #endif
290 #else
291 vec_max = 0;
292 vec_ri = 0;
293 vec_ro = 0;
294 vec_wi = 0;
295 vec_wo = 0;
296 #ifdef _WIN32
297 vec_eo = 0;
298 #endif
299 #endif
300
301 return EVBACKEND_SELECT;
302 }
303
304 inline_size
305 void
306 select_destroy (EV_P)
307 {
308 ev_free (vec_ri);
309 ev_free (vec_ro);
310 ev_free (vec_wi);
311 ev_free (vec_wo);
312 #ifdef _WIN32
313 ev_free (vec_eo);
314 #endif
315 }
316