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/cvs/libev/ev_select.c
Revision: 1.46
Committed: Sun Jul 19 04:06:13 2009 UTC (15 years ago) by root
Content type: text/plain
Branch: MAIN
CVS Tags: rel-3_9, rel-3_8
Changes since 1.45: +8 -2 lines
Log Message:
*** empty log message ***

File Contents

# Content
1 /*
2 * libev select fd activity backend
3 *
4 * Copyright (c) 2007,2008,2009 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 <sys/select.h>
43 # include <inttypes.h>
44 #endif
45
46 #ifndef EV_SELECT_USE_FD_SET
47 # ifdef NFDBITS
48 # define EV_SELECT_USE_FD_SET 0
49 # else
50 # define EV_SELECT_USE_FD_SET 1
51 # endif
52 #endif
53
54 #if EV_SELECT_IS_WINSOCKET
55 # undef EV_SELECT_USE_FD_SET
56 # define EV_SELECT_USE_FD_SET 1
57 # undef NFDBITS
58 # define NFDBITS 0
59 #endif
60
61 #if !EV_SELECT_USE_FD_SET
62 # define NFDBYTES (NFDBITS / 8)
63 #endif
64
65 #include <string.h>
66
67 static void
68 select_modify (EV_P_ int fd, int oev, int nev)
69 {
70 if (oev == nev)
71 return;
72
73 {
74 #if EV_SELECT_USE_FD_SET
75
76 #if EV_SELECT_IS_WINSOCKET
77 SOCKET handle = anfds [fd].handle;
78 #else
79 int handle = fd;
80 #endif
81
82 assert (("libev: fd >= FD_SETSIZE passed to fd_set-based select backend", fd < FD_SETSIZE));
83
84 /* FD_SET is broken on windows (it adds the fd to a set twice or more,
85 * which eventually leads to overflows). Need to call it only on changes.
86 */
87 #if EV_SELECT_IS_WINSOCKET
88 if ((oev ^ nev) & EV_READ)
89 #endif
90 if (nev & EV_READ)
91 FD_SET (handle, (fd_set *)vec_ri);
92 else
93 FD_CLR (handle, (fd_set *)vec_ri);
94
95 #if EV_SELECT_IS_WINSOCKET
96 if ((oev ^ nev) & EV_WRITE)
97 #endif
98 if (nev & EV_WRITE)
99 FD_SET (handle, (fd_set *)vec_wi);
100 else
101 FD_CLR (handle, (fd_set *)vec_wi);
102
103 #else
104
105 int word = fd / NFDBITS;
106 fd_mask mask = 1UL << (fd % NFDBITS);
107
108 if (expect_false (vec_max <= word))
109 {
110 int new_max = word + 1;
111
112 vec_ri = ev_realloc (vec_ri, new_max * NFDBYTES);
113 vec_ro = ev_realloc (vec_ro, new_max * NFDBYTES); /* could free/malloc */
114 vec_wi = ev_realloc (vec_wi, new_max * NFDBYTES);
115 vec_wo = ev_realloc (vec_wo, new_max * NFDBYTES); /* could free/malloc */
116 #ifdef _WIN32
117 vec_eo = ev_realloc (vec_eo, new_max * NFDBYTES); /* could free/malloc */
118 #endif
119
120 for (; vec_max < new_max; ++vec_max)
121 ((fd_mask *)vec_ri) [vec_max] =
122 ((fd_mask *)vec_wi) [vec_max] = 0;
123 }
124
125 ((fd_mask *)vec_ri) [word] |= mask;
126 if (!(nev & EV_READ))
127 ((fd_mask *)vec_ri) [word] &= ~mask;
128
129 ((fd_mask *)vec_wi) [word] |= mask;
130 if (!(nev & EV_WRITE))
131 ((fd_mask *)vec_wi) [word] &= ~mask;
132 #endif
133 }
134 }
135
136 static void
137 select_poll (EV_P_ ev_tstamp timeout)
138 {
139 struct timeval tv;
140 int res;
141 int fd_setsize;
142
143 EV_RELEASE_CB;
144 tv.tv_sec = (long)timeout;
145 tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
146
147 #if EV_SELECT_USE_FD_SET
148 fd_setsize = sizeof (fd_set);
149 #else
150 fd_setsize = vec_max * NFDBYTES;
151 #endif
152
153 memcpy (vec_ro, vec_ri, fd_setsize);
154 memcpy (vec_wo, vec_wi, fd_setsize);
155
156 #ifdef _WIN32
157 /* pass in the write set as except set.
158 * the idea behind this is to work around a windows bug that causes
159 * errors to be reported as an exception and not by setting
160 * the writable bit. this is so uncontrollably lame.
161 */
162 memcpy (vec_eo, vec_wi, fd_setsize);
163 res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, (fd_set *)vec_eo, &tv);
164 #elif EV_SELECT_USE_FD_SET
165 fd_setsize = anfdmax < FD_SETSIZE ? anfdmax : FD_SETSIZE;
166 res = select (fd_setsize, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
167 #else
168 res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
169 #endif
170 EV_ACQUIRE_CB;
171
172 if (expect_false (res < 0))
173 {
174 #if EV_SELECT_IS_WINSOCKET
175 errno = WSAGetLastError ();
176 #endif
177 #ifdef WSABASEERR
178 /* on windows, select returns incompatible error codes, fix this */
179 if (errno >= WSABASEERR && errno < WSABASEERR + 1000)
180 if (errno == WSAENOTSOCK)
181 errno = EBADF;
182 else
183 errno -= WSABASEERR;
184 #endif
185
186 #ifdef _WIN32
187 /* select on windows errornously returns EINVAL when no fd sets have been
188 * provided (this is documented). what microsoft doesn't tell you that this bug
189 * exists even when the fd sets _are_ provided, so we have to check for this bug
190 * here and emulate by sleeping manually.
191 * we also get EINVAL when the timeout is invalid, but we ignore this case here
192 * and assume that EINVAL always means: you have to wait manually.
193 */
194 if (errno == EINVAL)
195 {
196 ev_sleep (timeout);
197 return;
198 }
199 #endif
200
201 if (errno == EBADF)
202 fd_ebadf (EV_A);
203 else if (errno == ENOMEM && !syserr_cb)
204 fd_enomem (EV_A);
205 else if (errno != EINTR)
206 ev_syserr ("(libev) select");
207
208 return;
209 }
210
211 #if EV_SELECT_USE_FD_SET
212
213 {
214 int fd;
215
216 for (fd = 0; fd < anfdmax; ++fd)
217 if (anfds [fd].events)
218 {
219 int events = 0;
220 #if EV_SELECT_IS_WINSOCKET
221 SOCKET handle = anfds [fd].handle;
222 #else
223 int handle = fd;
224 #endif
225
226 if (FD_ISSET (handle, (fd_set *)vec_ro)) events |= EV_READ;
227 if (FD_ISSET (handle, (fd_set *)vec_wo)) events |= EV_WRITE;
228 #ifdef _WIN32
229 if (FD_ISSET (handle, (fd_set *)vec_eo)) events |= EV_WRITE;
230 #endif
231
232 if (expect_true (events))
233 fd_event (EV_A_ fd, events);
234 }
235 }
236
237 #else
238
239 {
240 int word, bit;
241 for (word = vec_max; word--; )
242 {
243 fd_mask word_r = ((fd_mask *)vec_ro) [word];
244 fd_mask word_w = ((fd_mask *)vec_wo) [word];
245 #ifdef _WIN32
246 word_w |= ((fd_mask *)vec_eo) [word];
247 #endif
248
249 if (word_r || word_w)
250 for (bit = NFDBITS; bit--; )
251 {
252 fd_mask mask = 1UL << bit;
253 int events = 0;
254
255 events |= word_r & mask ? EV_READ : 0;
256 events |= word_w & mask ? EV_WRITE : 0;
257
258 if (expect_true (events))
259 fd_event (EV_A_ word * NFDBITS + bit, events);
260 }
261 }
262 }
263
264 #endif
265 }
266
267 int inline_size
268 select_init (EV_P_ int flags)
269 {
270 backend_fudge = 0.; /* posix says this is zero */
271 backend_modify = select_modify;
272 backend_poll = select_poll;
273
274 #if EV_SELECT_USE_FD_SET
275 vec_ri = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_ri);
276 vec_ro = ev_malloc (sizeof (fd_set));
277 vec_wi = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_wi);
278 vec_wo = ev_malloc (sizeof (fd_set));
279 #ifdef _WIN32
280 vec_eo = ev_malloc (sizeof (fd_set));
281 #endif
282 #else
283 vec_max = 0;
284 vec_ri = 0;
285 vec_ro = 0;
286 vec_wi = 0;
287 vec_wo = 0;
288 #ifdef _WIN32
289 vec_eo = 0;
290 #endif
291 #endif
292
293 return EVBACKEND_SELECT;
294 }
295
296 void inline_size
297 select_destroy (EV_P)
298 {
299 ev_free (vec_ri);
300 ev_free (vec_ro);
301 ev_free (vec_wi);
302 ev_free (vec_wo);
303 #ifdef _WIN32
304 ev_free (vec_eo);
305 #endif
306 }
307
308