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/cvs/libev/ev_select.c
Revision: 1.38
Committed: Wed Oct 29 06:32:48 2008 UTC (15 years, 8 months ago) by root
Content type: text/plain
Branch: MAIN
CVS Tags: rel-3_51, rel-3_48, rel-3_49
Changes since 1.37: +1 -1 lines
Log Message:
*** empty log message ***

File Contents

# Content
1 /*
2 * libev select fd activity backend
3 *
4 * Copyright (c) 2007,2008 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 /* FD_SET is broken on windows (it adds the fd to a set twice or more,
83 * which eventually leads to overflows). Need to call it only on changes.
84 */
85 #if EV_SELECT_IS_WINSOCKET
86 if ((oev ^ nev) & EV_READ)
87 #endif
88 if (nev & EV_READ)
89 FD_SET (handle, (fd_set *)vec_ri);
90 else
91 FD_CLR (handle, (fd_set *)vec_ri);
92
93 #if EV_SELECT_IS_WINSOCKET
94 if ((oev ^ nev) & EV_WRITE)
95 #endif
96 if (nev & EV_WRITE)
97 FD_SET (handle, (fd_set *)vec_wi);
98 else
99 FD_CLR (handle, (fd_set *)vec_wi);
100
101 #else
102
103 int word = fd / NFDBITS;
104 fd_mask mask = 1UL << (fd % NFDBITS);
105
106 if (expect_false (vec_max <= word))
107 {
108 int new_max = word + 1;
109
110 vec_ri = ev_realloc (vec_ri, new_max * NFDBYTES);
111 vec_ro = ev_realloc (vec_ro, new_max * NFDBYTES); /* could free/malloc */
112 vec_wi = ev_realloc (vec_wi, new_max * NFDBYTES);
113 vec_wo = ev_realloc (vec_wo, new_max * NFDBYTES); /* could free/malloc */
114 #ifdef _WIN32
115 vec_eo = ev_realloc (vec_eo, new_max * NFDBYTES); /* could free/malloc */
116 #endif
117
118 for (; vec_max < new_max; ++vec_max)
119 ((fd_mask *)vec_ri) [vec_max] =
120 ((fd_mask *)vec_wi) [vec_max] = 0;
121 }
122
123 ((fd_mask *)vec_ri) [word] |= mask;
124 if (!(nev & EV_READ))
125 ((fd_mask *)vec_ri) [word] &= ~mask;
126
127 ((fd_mask *)vec_wi) [word] |= mask;
128 if (!(nev & EV_WRITE))
129 ((fd_mask *)vec_wi) [word] &= ~mask;
130 #endif
131 }
132 }
133
134 static void
135 select_poll (EV_P_ ev_tstamp timeout)
136 {
137 struct timeval tv;
138 int res;
139 int fd_setsize;
140
141 tv.tv_sec = (long)timeout;
142 tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
143
144 #if EV_SELECT_USE_FD_SET
145 fd_setsize = sizeof (fd_set);
146 #else
147 fd_setsize = vec_max * NFDBYTES;
148 #endif
149
150 memcpy (vec_ro, vec_ri, fd_setsize);
151 memcpy (vec_wo, vec_wi, fd_setsize);
152
153 #ifdef _WIN32
154 /* pass in the write set as except set.
155 * the idea behind this is to work around a windows bug that causes
156 * errors to be reported as an exception and not by setting
157 * the writable bit. this is so uncontrollably lame.
158 */
159 memcpy (vec_eo, vec_wi, fd_setsize);
160 res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, (fd_set *)vec_eo, &tv);
161 #else
162 res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
163 #endif
164
165 if (expect_false (res < 0))
166 {
167 #if EV_SELECT_IS_WINSOCKET
168 errno = WSAGetLastError ();
169 #endif
170 #ifdef WSABASEERR
171 /* on windows, select returns incompatible error codes, fix this */
172 if (errno >= WSABASEERR && errno < WSABASEERR + 1000)
173 if (errno == WSAENOTSOCK)
174 errno = EBADF;
175 else
176 errno -= WSABASEERR;
177 #endif
178
179 #ifdef _WIN32
180 /* select on windows errornously returns EINVAL when no fd sets have been
181 * provided (this is documented). what microsoft doesn't tell you that this bug
182 * exists even when the fd sets are provided, so we have to check for this bug
183 * here and emulate by sleeping manually.
184 * we also get EINVAL when the timeout is invalid, but we ignore this case here
185 * and assume that EINVAL always means: you have to wait manually.
186 */
187 if (errno == EINVAL)
188 {
189 ev_sleep (timeout);
190 return;
191 }
192 #endif
193
194 if (errno == EBADF)
195 fd_ebadf (EV_A);
196 else if (errno == ENOMEM && !syserr_cb)
197 fd_enomem (EV_A);
198 else if (errno != EINTR)
199 ev_syserr ("(libev) select");
200
201 return;
202 }
203
204 #if EV_SELECT_USE_FD_SET
205
206 {
207 int fd;
208
209 for (fd = 0; fd < anfdmax; ++fd)
210 if (anfds [fd].events)
211 {
212 int events = 0;
213 #if EV_SELECT_IS_WINSOCKET
214 SOCKET handle = anfds [fd].handle;
215 #else
216 int handle = fd;
217 #endif
218
219 if (FD_ISSET (handle, (fd_set *)vec_ro)) events |= EV_READ;
220 if (FD_ISSET (handle, (fd_set *)vec_wo)) events |= EV_WRITE;
221 #ifdef _WIN32
222 if (FD_ISSET (handle, (fd_set *)vec_eo)) events |= EV_WRITE;
223 #endif
224
225 if (expect_true (events))
226 fd_event (EV_A_ fd, events);
227 }
228 }
229
230 #else
231
232 {
233 int word, bit;
234 for (word = vec_max; word--; )
235 {
236 fd_mask word_r = ((fd_mask *)vec_ro) [word];
237 fd_mask word_w = ((fd_mask *)vec_wo) [word];
238 #ifdef _WIN32
239 word_w |= ((fd_mask *)vec_eo) [word];
240 #endif
241
242 if (word_r || word_w)
243 for (bit = NFDBITS; bit--; )
244 {
245 fd_mask mask = 1UL << bit;
246 int events = 0;
247
248 events |= word_r & mask ? EV_READ : 0;
249 events |= word_w & mask ? EV_WRITE : 0;
250
251 if (expect_true (events))
252 fd_event (EV_A_ word * NFDBITS + bit, events);
253 }
254 }
255 }
256
257 #endif
258 }
259
260 int inline_size
261 select_init (EV_P_ int flags)
262 {
263 backend_fudge = 0.; /* posix says this is zero */
264 backend_modify = select_modify;
265 backend_poll = select_poll;
266
267 #if EV_SELECT_USE_FD_SET
268 vec_max = FD_SETSIZE / 32;
269 vec_ri = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_ri);
270 vec_ro = ev_malloc (sizeof (fd_set));
271 vec_wi = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_wi);
272 vec_wo = ev_malloc (sizeof (fd_set));
273 #ifdef _WIN32
274 vec_eo = ev_malloc (sizeof (fd_set));
275 #endif
276 #else
277 vec_max = 0;
278 vec_ri = 0;
279 vec_ri = 0;
280 vec_wo = 0;
281 vec_wo = 0;
282 #endif
283
284 return EVBACKEND_SELECT;
285 }
286
287 void inline_size
288 select_destroy (EV_P)
289 {
290 ev_free (vec_ri);
291 ev_free (vec_ro);
292 ev_free (vec_wi);
293 ev_free (vec_wo);
294 }
295
296