libev/ev_select.c

/*
 * libev select fd activity backend
 *
 * Copyright (c) 2007,2008 Marc Alexander Lehmann <libev@schmorp.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 * 
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 * 
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 */

#ifndef _WIN32
/* for unix systems */
# include <sys/select.h>
# include <inttypes.h>
#endif

#ifndef EV_SELECT_USE_FD_SET
# ifdef NFDBITS
#  define EV_SELECT_USE_FD_SET 0
# else
#  define EV_SELECT_USE_FD_SET 1
# endif
#endif

#if EV_SELECT_IS_WINSOCKET
# undef EV_SELECT_USE_FD_SET
# define EV_SELECT_USE_FD_SET 1
# undef NFDBITS
# define NFDBITS 0
#endif

#if !EV_SELECT_USE_FD_SET
# define NFDBYTES (NFDBITS / 8)
#endif

#include <string.h>

static void
select_modify (EV_P_ int fd, int oev, int nev)
{
  if (oev == nev)
    return;

  {
#if EV_SELECT_USE_FD_SET

    #if EV_SELECT_IS_WINSOCKET
    SOCKET handle = anfds [fd].handle;
    #else
    int handle = fd;
    #endif

    /* FD_SET is broken on windows (it adds the fd to a set twice or more,
     * which eventually leads to overflows). Need to call it only on changes.
     */
    #if EV_SELECT_IS_WINSOCKET
    if ((oev ^ nev) & EV_READ)
    #endif
      if (nev & EV_READ)
        FD_SET (handle, (fd_set *)vec_ri);
      else
        FD_CLR (handle, (fd_set *)vec_ri);

    #if EV_SELECT_IS_WINSOCKET
    if ((oev ^ nev) & EV_WRITE)
    #endif
      if (nev & EV_WRITE)
        FD_SET (handle, (fd_set *)vec_wi);
      else
        FD_CLR (handle, (fd_set *)vec_wi);

#else

    int     word = fd / NFDBITS;
    fd_mask mask = 1UL << (fd % NFDBITS);

    if (expect_false (vec_max <= word))
      {
        int new_max = word + 1;

        vec_ri = ev_realloc (vec_ri, new_max * NFDBYTES);
        vec_ro = ev_realloc (vec_ro, new_max * NFDBYTES); /* could free/malloc */
        vec_wi = ev_realloc (vec_wi, new_max * NFDBYTES);
        vec_wo = ev_realloc (vec_wo, new_max * NFDBYTES); /* could free/malloc */
        #ifdef _WIN32
        vec_eo = ev_realloc (vec_eo, new_max * NFDBYTES); /* could free/malloc */
        #endif

        for (; vec_max < new_max; ++vec_max)
          ((fd_mask *)vec_ri) [vec_max] =
          ((fd_mask *)vec_wi) [vec_max] = 0;
      }

    ((fd_mask *)vec_ri) [word] |= mask;
    if (!(nev & EV_READ))
      ((fd_mask *)vec_ri) [word] &= ~mask;

    ((fd_mask *)vec_wi) [word] |= mask;
    if (!(nev & EV_WRITE))
      ((fd_mask *)vec_wi) [word] &= ~mask;
#endif
  }
}

static void
select_poll (EV_P_ ev_tstamp timeout)
{
  struct timeval tv;
  int res;
  int fd_setsize;

  tv.tv_sec  = (long)timeout;
  tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);

#if EV_SELECT_USE_FD_SET
  fd_setsize = sizeof (fd_set);
#else
  fd_setsize = vec_max * NFDBYTES;
#endif

  memcpy (vec_ro, vec_ri, fd_setsize);
  memcpy (vec_wo, vec_wi, fd_setsize);

#ifdef _WIN32
  /* pass in the write set as except set.
   * the idea behind this is to work around a windows bug that causes
   * errors to be reported as an exception and not by setting
   * the writable bit. this is so uncontrollably lame.
   */
  memcpy (vec_eo, vec_wi, fd_setsize);
  res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, (fd_set *)vec_eo, &tv);
#else
  res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
#endif

  if (expect_false (res < 0))
    {
      #if EV_SELECT_IS_WINSOCKET
      errno = WSAGetLastError ();
      #endif
      #ifdef WSABASEERR
      /* on windows, select returns incompatible error codes, fix this */
      if (errno >= WSABASEERR && errno < WSABASEERR + 1000)
        if (errno == WSAENOTSOCK)
          errno = EBADF;
        else
          errno -= WSABASEERR;
      #endif

      #ifdef _WIN32
      /* select on windows errornously returns EINVAL when no fd sets have been
       * provided (this is documented). what microsoft doesn't tell you that this bug
       * exists even when the fd sets are provided, so we have to check for this bug
       * here and emulate by sleeping manually.
       * we also get EINVAL when the timeout is invalid, but we ignore this case here
       * and assume that EINVAL always means: you have to wait manually.
       */
      if (errno == EINVAL)
        {
          ev_sleep (timeout);
          return;
        }
      #endif

      if (errno == EBADF)
        fd_ebadf (EV_A);
      else if (errno == ENOMEM && !syserr_cb)
        fd_enomem (EV_A);
      else if (errno != EINTR)
        syserr ("(libev) select");

      return;
    }

#if EV_SELECT_USE_FD_SET

  {
    int fd;

    for (fd = 0; fd < anfdmax; ++fd)
      if (anfds [fd].events)
        {
          int events = 0;
          #if EV_SELECT_IS_WINSOCKET
          SOCKET handle = anfds [fd].handle;
          #else
          int handle = fd;
          #endif

          if (FD_ISSET (handle, (fd_set *)vec_ro)) events |= EV_READ;
          if (FD_ISSET (handle, (fd_set *)vec_wo)) events |= EV_WRITE;
          #ifdef _WIN32
          if (FD_ISSET (handle, (fd_set *)vec_eo)) events |= EV_WRITE;
          #endif

          if (expect_true (events))
            fd_event (EV_A_ fd, events);
        }
  }

#else

  {
    int word, bit;
    for (word = vec_max; word--; )
      {
        fd_mask word_r = ((fd_mask *)vec_ro) [word];
        fd_mask word_w = ((fd_mask *)vec_wo) [word];
        #ifdef _WIN32
        word_w |= ((fd_mask *)vec_eo) [word];
        #endif

        if (word_r || word_w)
          for (bit = NFDBITS; bit--; )
            {
              fd_mask mask = 1UL << bit;
              int events = 0;

              events |= word_r & mask ? EV_READ  : 0;
              events |= word_w & mask ? EV_WRITE : 0;

              if (expect_true (events))
                fd_event (EV_A_ word * NFDBITS + bit, events);
            }
      }
  }

#endif
}

int inline_size
select_init (EV_P_ int flags)
{
  backend_fudge  = 0.; /* posix says this is zero */
  backend_modify = select_modify;
  backend_poll   = select_poll;

#if EV_SELECT_USE_FD_SET
  vec_max = FD_SETSIZE / 32;
  vec_ri  = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_ri);
  vec_ro  = ev_malloc (sizeof (fd_set));
  vec_wi  = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_wi);
  vec_wo  = ev_malloc (sizeof (fd_set));
  #ifdef _WIN32
  vec_eo  = ev_malloc (sizeof (fd_set));
  #endif
#else
  vec_max = 0;
  vec_ri  = 0; 
  vec_ri  = 0;   
  vec_wo  = 0; 
  vec_wo  = 0; 
#endif

  return EVBACKEND_SELECT;
}

void inline_size
select_destroy (EV_P)
{
  ev_free (vec_ri);
  ev_free (vec_ro);
  ev_free (vec_wi);
  ev_free (vec_wo);
}


Revision:	1.37
Committed:	Mon Jun 9 14:11:30 2008 UTC (16 years, 4 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-3_44, rel-3_45, rel-3_42, rel-3_43, rel-3_431
Changes since 1.36:	+18 -9 lines
Log Message:	* empty log message *
#	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	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