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)
        ev_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:	1.38
Committed:	Wed Oct 29 06:32:48 2008 UTC (15 years, 6 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 *
#	User	Rev	Content
1	root	1.4	/*
2	root	1.7	* libev select fd activity backend
3			*
4	root	1.31	* Copyright (c) 2007,2008 Marc Alexander Lehmann <libev@schmorp.de>
5	root	1.4	* All rights reserved.
6			*
7	root	1.27	* 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	root	1.4	*
28	root	1.27	* 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	root	1.4	*/
39
40	root	1.20	#ifndef _WIN32
41	root	1.2	/* for unix systems */
42	root	1.20	# 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	root	1.18	# define EV_SELECT_USE_FD_SET 1
51			# endif
52	root	1.9	#endif
53	root	1.2
54	root	1.20	#if EV_SELECT_IS_WINSOCKET
55	root	1.18	# undef EV_SELECT_USE_FD_SET
56			# define EV_SELECT_USE_FD_SET 1
57	root	1.36	# undef NFDBITS
58			# define NFDBITS 0
59	root	1.20	#endif
60
61			#if !EV_SELECT_USE_FD_SET
62			# define NFDBYTES (NFDBITS / 8)
63	root	1.18	#endif
64
65	root	1.2	#include <string.h>
66
67			static void
68	root	1.10	select_modify (EV_P_ int fd, int oev, int nev)
69	root	1.2	{
70	root	1.13	if (oev == nev)
71			return;
72
73	root	1.20	{
74	root	1.17	#if EV_SELECT_USE_FD_SET
75	root	1.18
76	root	1.20	#if EV_SELECT_IS_WINSOCKET
77			SOCKET handle = anfds [fd].handle;
78			#else
79			int handle = fd;
80			#endif
81
82	root	1.37	/* 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	root	1.20
101	root	1.17	#else
102
103	root	1.28	int word = fd / NFDBITS;
104			fd_mask mask = 1UL << (fd % NFDBITS);
105	root	1.20
106	root	1.29	if (expect_false (vec_max <= word))
107	root	1.17	{
108	root	1.20	int new_max = word + 1;
109	root	1.17
110	root	1.20	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	root	1.33	#ifdef _WIN32
115			vec_eo = ev_realloc (vec_eo, new_max * NFDBYTES); /* could free/malloc */
116			#endif
117	root	1.17
118			for (; vec_max < new_max; ++vec_max)
119	root	1.28	((fd_mask *)vec_ri) [vec_max] =
120			((fd_mask *)vec_wi) [vec_max] = 0;
121	root	1.17	}
122
123	root	1.20	((fd_mask *)vec_ri) [word] \|= mask;
124	root	1.17	if (!(nev & EV_READ))
125	root	1.20	((fd_mask *)vec_ri) [word] &= ~mask;
126	root	1.17
127	root	1.20	((fd_mask *)vec_wi) [word] \|= mask;
128	root	1.17	if (!(nev & EV_WRITE))
129	root	1.20	((fd_mask *)vec_wi) [word] &= ~mask;
130			#endif
131	root	1.17	}
132	root	1.2	}
133
134	root	1.6	static void
135	root	1.10	select_poll (EV_P_ ev_tstamp timeout)
136	root	1.2	{
137			struct timeval tv;
138			int res;
139	root	1.33	int fd_setsize;
140
141			tv.tv_sec = (long)timeout;
142			tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
143	root	1.2
144	root	1.17	#if EV_SELECT_USE_FD_SET
145	root	1.33	fd_setsize = sizeof (fd_set);
146	root	1.17	#else
147	root	1.33	fd_setsize = vec_max * NFDBYTES;
148	root	1.17	#endif
149	root	1.2
150	root	1.33	memcpy (vec_ro, vec_ri, fd_setsize);
151			memcpy (vec_wo, vec_wi, fd_setsize);
152	root	1.2
153	root	1.32	#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	root	1.33	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	root	1.32	#else
162	root	1.20	res = select (vec_max * NFDBITS, (fd_set )vec_ro, (fd_set )vec_wo, 0, &tv);
163	root	1.32	#endif
164	root	1.2
165	root	1.24	if (expect_false (res < 0))
166	root	1.2	{
167	root	1.20	#if EV_SELECT_IS_WINSOCKET
168			errno = WSAGetLastError ();
169			#endif
170	root	1.29	#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	root	1.17
194	root	1.14	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	root	1.38	ev_syserr ("(libev) select");
200	root	1.2
201	root	1.14	return;
202	root	1.2	}
203	root	1.14
204	root	1.17	#if EV_SELECT_USE_FD_SET
205	root	1.20
206			{
207			int fd;
208
209			for (fd = 0; fd < anfdmax; ++fd)
210			if (anfds [fd].events)
211	root	1.18	{
212	root	1.20	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	root	1.33	#ifdef _WIN32
222			if (FD_ISSET (handle, (fd_set *)vec_eo)) events \|= EV_WRITE;
223			#endif
224	root	1.20
225	root	1.24	if (expect_true (events))
226	root	1.20	fd_event (EV_A_ fd, events);
227			}
228			}
229	root	1.18
230	root	1.20	#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	root	1.33	#ifdef _WIN32
239			word_w \|= ((fd_mask *)vec_eo) [word];
240			#endif
241	root	1.20
242			if (word_r \|\| word_w)
243			for (bit = NFDBITS; bit--; )
244	root	1.18	{
245	root	1.20	fd_mask mask = 1UL << bit;
246	root	1.18	int events = 0;
247
248	root	1.20	events \|= word_r & mask ? EV_READ : 0;
249			events \|= word_w & mask ? EV_WRITE : 0;
250	root	1.18
251	root	1.24	if (expect_true (events))
252	root	1.20	fd_event (EV_A_ word * NFDBITS + bit, events);
253	root	1.18	}
254	root	1.20	}
255			}
256	root	1.17
257			#endif
258	root	1.2	}
259
260	root	1.23	int inline_size
261	root	1.10	select_init (EV_P_ int flags)
262	root	1.2	{
263	root	1.26	backend_fudge = 0.; /* posix says this is zero */
264	root	1.22	backend_modify = select_modify;
265			backend_poll = select_poll;
266	root	1.10
267	root	1.17	#if EV_SELECT_USE_FD_SET
268			vec_max = FD_SETSIZE / 32;
269	root	1.20	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	root	1.33	#ifdef _WIN32
274			vec_eo = ev_malloc (sizeof (fd_set));
275			#endif
276	root	1.17	#else
277	root	1.12	vec_max = 0;
278			vec_ri = 0;
279			vec_ri = 0;
280			vec_wo = 0;
281			vec_wo = 0;
282	root	1.17	#endif
283	root	1.12
284	root	1.21	return EVBACKEND_SELECT;
285	root	1.2	}
286
287	root	1.23	void inline_size
288	root	1.12	select_destroy (EV_P)
289			{
290	root	1.14	ev_free (vec_ri);
291			ev_free (vec_ro);
292			ev_free (vec_wi);
293			ev_free (vec_wo);
294	root	1.12	}
295
296