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  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. #ifndef _WIN32
  40. /* for unix systems */
  41. # include <sys/select.h>
  42. # include <inttypes.h>
  43. #endif
  44. #ifndef EV_SELECT_USE_FD_SET
  45. # ifdef NFDBITS
  46. # define EV_SELECT_USE_FD_SET 0
  47. # else
  48. # define EV_SELECT_USE_FD_SET 1
  49. # endif
  50. #endif
  51. #if EV_SELECT_IS_WINSOCKET
  52. # undef EV_SELECT_USE_FD_SET
  53. # define EV_SELECT_USE_FD_SET 1
  54. # undef NFDBITS
  55. # define NFDBITS 0
  56. #endif
  57. #if !EV_SELECT_USE_FD_SET
  58. # define NFDBYTES (NFDBITS / 8)
  59. #endif
  60. #include <string.h>
  61. static void
  62. select_modify (EV_P_ int fd, int oev, int nev)
  63. {
  64. if (oev == nev)
  65. return;
  66. {
  67. #if EV_SELECT_USE_FD_SET
  68. #if EV_SELECT_IS_WINSOCKET
  69. SOCKET handle = anfds [fd].handle;
  70. #else
  71. int handle = fd;
  72. #endif
  73. /* FD_SET is broken on windows (it adds the fd to a set twice or more,
  74. * which eventually leads to overflows). Need to call it only on changes.
  75. */
  76. #if EV_SELECT_IS_WINSOCKET
  77. if ((oev ^ nev) & EV_READ)
  78. #endif
  79. if (nev & EV_READ)
  80. FD_SET (handle, (fd_set *)vec_ri);
  81. else
  82. FD_CLR (handle, (fd_set *)vec_ri);
  83. #if EV_SELECT_IS_WINSOCKET
  84. if ((oev ^ nev) & EV_WRITE)
  85. #endif
  86. if (nev & EV_WRITE)
  87. FD_SET (handle, (fd_set *)vec_wi);
  88. else
  89. FD_CLR (handle, (fd_set *)vec_wi);
  90. #else
  91. int word = fd / NFDBITS;
  92. fd_mask mask = 1UL << (fd % NFDBITS);
  93. if (expect_false (vec_max <= word))
  94. {
  95. int new_max = word + 1;
  96. vec_ri = ev_realloc (vec_ri, new_max * NFDBYTES);
  97. vec_ro = ev_realloc (vec_ro, new_max * NFDBYTES); /* could free/malloc */
  98. vec_wi = ev_realloc (vec_wi, new_max * NFDBYTES);
  99. vec_wo = ev_realloc (vec_wo, new_max * NFDBYTES); /* could free/malloc */
  100. #ifdef _WIN32
  101. vec_eo = ev_realloc (vec_eo, new_max * NFDBYTES); /* could free/malloc */
  102. #endif
  103. for (; vec_max < new_max; ++vec_max)
  104. ((fd_mask *)vec_ri) [vec_max] =
  105. ((fd_mask *)vec_wi) [vec_max] = 0;
  106. }
  107. ((fd_mask *)vec_ri) [word] |= mask;
  108. if (!(nev & EV_READ))
  109. ((fd_mask *)vec_ri) [word] &= ~mask;
  110. ((fd_mask *)vec_wi) [word] |= mask;
  111. if (!(nev & EV_WRITE))
  112. ((fd_mask *)vec_wi) [word] &= ~mask;
  113. #endif
  114. }
  115. }
  116. static void
  117. select_poll (EV_P_ ev_tstamp timeout)
  118. {
  119. struct timeval tv;
  120. int res;
  121. int fd_setsize;
  122. tv.tv_sec = (long)timeout;
  123. tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
  124. #if EV_SELECT_USE_FD_SET
  125. fd_setsize = sizeof (fd_set);
  126. #else
  127. fd_setsize = vec_max * NFDBYTES;
  128. #endif
  129. memcpy (vec_ro, vec_ri, fd_setsize);
  130. memcpy (vec_wo, vec_wi, fd_setsize);
  131. #ifdef _WIN32
  132. /* pass in the write set as except set.
  133. * the idea behind this is to work around a windows bug that causes
  134. * errors to be reported as an exception and not by setting
  135. * the writable bit. this is so uncontrollably lame.
  136. */
  137. memcpy (vec_eo, vec_wi, fd_setsize);
  138. res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, (fd_set *)vec_eo, &tv);
  139. #else
  140. res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
  141. #endif
  142. if (expect_false (res < 0))
  143. {
  144. #if EV_SELECT_IS_WINSOCKET
  145. errno = WSAGetLastError ();
  146. #endif
  147. #ifdef WSABASEERR
  148. /* on windows, select returns incompatible error codes, fix this */
  149. if (errno >= WSABASEERR && errno < WSABASEERR + 1000)
  150. if (errno == WSAENOTSOCK)
  151. errno = EBADF;
  152. else
  153. errno -= WSABASEERR;
  154. #endif
  155. #ifdef _WIN32
  156. /* select on windows errornously returns EINVAL when no fd sets have been
  157. * provided (this is documented). what microsoft doesn't tell you that this bug
  158. * exists even when the fd sets are provided, so we have to check for this bug
  159. * here and emulate by sleeping manually.
  160. * we also get EINVAL when the timeout is invalid, but we ignore this case here
  161. * and assume that EINVAL always means: you have to wait manually.
  162. */
  163. if (errno == EINVAL)
  164. {
  165. ev_sleep (timeout);
  166. return;
  167. }
  168. #endif
  169. if (errno == EBADF)
  170. fd_ebadf (EV_A);
  171. else if (errno == ENOMEM && !syserr_cb)
  172. fd_enomem (EV_A);
  173. else if (errno != EINTR)
  174. syserr ("(libev) select");
  175. return;
  176. }
  177. #if EV_SELECT_USE_FD_SET
  178. {
  179. int fd;
  180. for (fd = 0; fd < anfdmax; ++fd)
  181. if (anfds [fd].events)
  182. {
  183. int events = 0;
  184. #if EV_SELECT_IS_WINSOCKET
  185. SOCKET handle = anfds [fd].handle;
  186. #else
  187. int handle = fd;
  188. #endif
  189. if (FD_ISSET (handle, (fd_set *)vec_ro)) events |= EV_READ;
  190. if (FD_ISSET (handle, (fd_set *)vec_wo)) events |= EV_WRITE;
  191. #ifdef _WIN32
  192. if (FD_ISSET (handle, (fd_set *)vec_eo)) events |= EV_WRITE;
  193. #endif
  194. if (expect_true (events))
  195. fd_event (EV_A_ fd, events);
  196. }
  197. }
  198. #else
  199. {
  200. int word, bit;
  201. for (word = vec_max; word--; )
  202. {
  203. fd_mask word_r = ((fd_mask *)vec_ro) [word];
  204. fd_mask word_w = ((fd_mask *)vec_wo) [word];
  205. #ifdef _WIN32
  206. word_w |= ((fd_mask *)vec_eo) [word];
  207. #endif
  208. if (word_r || word_w)
  209. for (bit = NFDBITS; bit--; )
  210. {
  211. fd_mask mask = 1UL << bit;
  212. int events = 0;
  213. events |= word_r & mask ? EV_READ : 0;
  214. events |= word_w & mask ? EV_WRITE : 0;
  215. if (expect_true (events))
  216. fd_event (EV_A_ word * NFDBITS + bit, events);
  217. }
  218. }
  219. }
  220. #endif
  221. }
  222. int inline_size
  223. select_init (EV_P_ int flags)
  224. {
  225. backend_fudge = 0.; /* posix says this is zero */
  226. backend_modify = select_modify;
  227. backend_poll = select_poll;
  228. #if EV_SELECT_USE_FD_SET
  229. vec_max = FD_SETSIZE / 32;
  230. vec_ri = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_ri);
  231. vec_ro = ev_malloc (sizeof (fd_set));
  232. vec_wi = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_wi);
  233. vec_wo = ev_malloc (sizeof (fd_set));
  234. #ifdef _WIN32
  235. vec_eo = ev_malloc (sizeof (fd_set));
  236. #endif
  237. #else
  238. vec_max = 0;
  239. vec_ri = 0;
  240. vec_ri = 0;
  241. vec_wo = 0;
  242. vec_wo = 0;
  243. #endif
  244. return EVBACKEND_SELECT;
  245. }
  246. void inline_size
  247. select_destroy (EV_P)
  248. {
  249. ev_free (vec_ri);
  250. ev_free (vec_ro);
  251. ev_free (vec_wi);
  252. ev_free (vec_wo);
  253. }