libev/ev_select.c

/*
 * libev select fd activity backend
 *
 * Copyright (c) 2007,2008,2009,2010,2011 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 <inttypes.h>
# ifndef __hpux
/* for REAL unix systems */
#  include <sys/select.h>
# endif
#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

    assert (("libev: fd >= FD_SETSIZE passed to fd_set-based select backend", fd < FD_SETSIZE));

    /* 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 (ecb_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;

  EV_RELEASE_CB;
  EV_TV_SET (tv, timeout);

#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);
#elif EV_SELECT_USE_FD_SET
  fd_setsize = anfdmax < FD_SETSIZE ? anfdmax : FD_SETSIZE;
  res = select (fd_setsize, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
#else
  res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
#endif
  EV_ACQUIRE_CB;

  if (ecb_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 erroneously 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)
        {
          if (timeout)
            {
              unsigned long ms = EV_TS_TO_MSEC (timeout);
              Sleep (ms ? ms : 1);
            }

          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 (ecb_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 (ecb_expect_true (events))
                fd_event (EV_A_ word * NFDBITS + bit, events);
            }
      }
  }

#endif
}

inline_size
int
select_init (EV_P_ int flags)
{
  backend_mintime = EV_TS_CONST (1e-6);
  backend_modify  = select_modify;
  backend_poll    = select_poll;

#if EV_SELECT_USE_FD_SET
  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_ro  = 0;
  vec_wi  = 0;
  vec_wo  = 0;
  #ifdef _WIN32
  vec_eo  = 0;
  #endif
#endif

  return EVBACKEND_SELECT;
}

inline_size
void
select_destroy (EV_P)
{
  ev_free (vec_ri);
  ev_free (vec_ro);
  ev_free (vec_wi);
  ev_free (vec_wo);
  #ifdef _WIN32
  ev_free (vec_eo);
  #endif
}

Revision:	1.58
Committed:	Sat Aug 17 05:30:16 2019 UTC (4 years, 8 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	EV-rel-4_28, EV-rel-4_29, rel-4_33, EV-rel-4_31, EV-rel-4_30, rel-4_31, HEAD
Changes since 1.57:	+2 -2 lines
Log Message:	* empty log message *
#	Content
1	/*
2	* libev select fd activity backend
3	*
4	* Copyright (c) 2007,2008,2009,2010,2011 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 <inttypes.h>
43	# ifndef __hpux
44	/* for REAL unix systems */
45	# include <sys/select.h>
46	# endif
47	#endif
48
49	#ifndef EV_SELECT_USE_FD_SET
50	# ifdef NFDBITS
51	# define EV_SELECT_USE_FD_SET 0
52	# else
53	# define EV_SELECT_USE_FD_SET 1
54	# endif
55	#endif
56
57	#if EV_SELECT_IS_WINSOCKET
58	# undef EV_SELECT_USE_FD_SET
59	# define EV_SELECT_USE_FD_SET 1
60	# undef NFDBITS
61	# define NFDBITS 0
62	#endif
63
64	#if !EV_SELECT_USE_FD_SET
65	# define NFDBYTES (NFDBITS / 8)
66	#endif
67
68	#include <string.h>
69
70	static void
71	select_modify (EV_P_ int fd, int oev, int nev)
72	{
73	if (oev == nev)
74	return;
75
76	{
77	#if EV_SELECT_USE_FD_SET
78
79	#if EV_SELECT_IS_WINSOCKET
80	SOCKET handle = anfds [fd].handle;
81	#else
82	int handle = fd;
83	#endif
84
85	assert (("libev: fd >= FD_SETSIZE passed to fd_set-based select backend", fd < FD_SETSIZE));
86
87	/* FD_SET is broken on windows (it adds the fd to a set twice or more,
88	* which eventually leads to overflows). Need to call it only on changes.
89	*/
90	#if EV_SELECT_IS_WINSOCKET
91	if ((oev ^ nev) & EV_READ)
92	#endif
93	if (nev & EV_READ)
94	FD_SET (handle, (fd_set *)vec_ri);
95	else
96	FD_CLR (handle, (fd_set *)vec_ri);
97
98	#if EV_SELECT_IS_WINSOCKET
99	if ((oev ^ nev) & EV_WRITE)
100	#endif
101	if (nev & EV_WRITE)
102	FD_SET (handle, (fd_set *)vec_wi);
103	else
104	FD_CLR (handle, (fd_set *)vec_wi);
105
106	#else
107
108	int word = fd / NFDBITS;
109	fd_mask mask = 1UL << (fd % NFDBITS);
110
111	if (ecb_expect_false (vec_max <= word))
112	{
113	int new_max = word + 1;
114
115	vec_ri = ev_realloc (vec_ri, new_max * NFDBYTES);
116	vec_ro = ev_realloc (vec_ro, new_max * NFDBYTES); /* could free/malloc */
117	vec_wi = ev_realloc (vec_wi, new_max * NFDBYTES);
118	vec_wo = ev_realloc (vec_wo, new_max * NFDBYTES); /* could free/malloc */
119	#ifdef _WIN32
120	vec_eo = ev_realloc (vec_eo, new_max * NFDBYTES); /* could free/malloc */
121	#endif
122
123	for (; vec_max < new_max; ++vec_max)
124	((fd_mask *)vec_ri) [vec_max] =
125	((fd_mask *)vec_wi) [vec_max] = 0;
126	}
127
128	((fd_mask *)vec_ri) [word] \|= mask;
129	if (!(nev & EV_READ))
130	((fd_mask *)vec_ri) [word] &= ~mask;
131
132	((fd_mask *)vec_wi) [word] \|= mask;
133	if (!(nev & EV_WRITE))
134	((fd_mask *)vec_wi) [word] &= ~mask;
135	#endif
136	}
137	}
138
139	static void
140	select_poll (EV_P_ ev_tstamp timeout)
141	{
142	struct timeval tv;
143	int res;
144	int fd_setsize;
145
146	EV_RELEASE_CB;
147	EV_TV_SET (tv, timeout);
148
149	#if EV_SELECT_USE_FD_SET
150	fd_setsize = sizeof (fd_set);
151	#else
152	fd_setsize = vec_max * NFDBYTES;
153	#endif
154
155	memcpy (vec_ro, vec_ri, fd_setsize);
156	memcpy (vec_wo, vec_wi, fd_setsize);
157
158	#ifdef _WIN32
159	/* pass in the write set as except set.
160	* the idea behind this is to work around a windows bug that causes
161	* errors to be reported as an exception and not by setting
162	* the writable bit. this is so uncontrollably lame.
163	*/
164	memcpy (vec_eo, vec_wi, fd_setsize);
165	res = select (vec_max * NFDBITS, (fd_set )vec_ro, (fd_set )vec_wo, (fd_set *)vec_eo, &tv);
166	#elif EV_SELECT_USE_FD_SET
167	fd_setsize = anfdmax < FD_SETSIZE ? anfdmax : FD_SETSIZE;
168	res = select (fd_setsize, (fd_set )vec_ro, (fd_set )vec_wo, 0, &tv);
169	#else
170	res = select (vec_max * NFDBITS, (fd_set )vec_ro, (fd_set )vec_wo, 0, &tv);
171	#endif
172	EV_ACQUIRE_CB;
173
174	if (ecb_expect_false (res < 0))
175	{
176	#if EV_SELECT_IS_WINSOCKET
177	errno = WSAGetLastError ();
178	#endif
179	#ifdef WSABASEERR
180	/* on windows, select returns incompatible error codes, fix this */
181	if (errno >= WSABASEERR && errno < WSABASEERR + 1000)
182	if (errno == WSAENOTSOCK)
183	errno = EBADF;
184	else
185	errno -= WSABASEERR;
186	#endif
187
188	#ifdef _WIN32
189	/* select on windows erroneously returns EINVAL when no fd sets have been
190	* provided (this is documented). what microsoft doesn't tell you that this bug
191	* exists even when the fd sets _are_ provided, so we have to check for this bug
192	* here and emulate by sleeping manually.
193	* we also get EINVAL when the timeout is invalid, but we ignore this case here
194	* and assume that EINVAL always means: you have to wait manually.
195	*/
196	if (errno == EINVAL)
197	{
198	if (timeout)
199	{
200	unsigned long ms = EV_TS_TO_MSEC (timeout);
201	Sleep (ms ? ms : 1);
202	}
203
204	return;
205	}
206	#endif
207
208	if (errno == EBADF)
209	fd_ebadf (EV_A);
210	else if (errno == ENOMEM && !syserr_cb)
211	fd_enomem (EV_A);
212	else if (errno != EINTR)
213	ev_syserr ("(libev) select");
214
215	return;
216	}
217
218	#if EV_SELECT_USE_FD_SET
219
220	{
221	int fd;
222
223	for (fd = 0; fd < anfdmax; ++fd)
224	if (anfds [fd].events)
225	{
226	int events = 0;
227	#if EV_SELECT_IS_WINSOCKET
228	SOCKET handle = anfds [fd].handle;
229	#else
230	int handle = fd;
231	#endif
232
233	if (FD_ISSET (handle, (fd_set *)vec_ro)) events \|= EV_READ;
234	if (FD_ISSET (handle, (fd_set *)vec_wo)) events \|= EV_WRITE;
235	#ifdef _WIN32
236	if (FD_ISSET (handle, (fd_set *)vec_eo)) events \|= EV_WRITE;
237	#endif
238
239	if (ecb_expect_true (events))
240	fd_event (EV_A_ fd, events);
241	}
242	}
243
244	#else
245
246	{
247	int word, bit;
248	for (word = vec_max; word--; )
249	{
250	fd_mask word_r = ((fd_mask *)vec_ro) [word];
251	fd_mask word_w = ((fd_mask *)vec_wo) [word];
252	#ifdef _WIN32
253	word_w \|= ((fd_mask *)vec_eo) [word];
254	#endif
255
256	if (word_r \|\| word_w)
257	for (bit = NFDBITS; bit--; )
258	{
259	fd_mask mask = 1UL << bit;
260	int events = 0;
261
262	events \|= word_r & mask ? EV_READ : 0;
263	events \|= word_w & mask ? EV_WRITE : 0;
264
265	if (ecb_expect_true (events))
266	fd_event (EV_A_ word * NFDBITS + bit, events);
267	}
268	}
269	}
270
271	#endif
272	}
273
274	inline_size
275	int
276	select_init (EV_P_ int flags)
277	{
278	backend_mintime = EV_TS_CONST (1e-6);
279	backend_modify = select_modify;
280	backend_poll = select_poll;
281
282	#if EV_SELECT_USE_FD_SET
283	vec_ri = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_ri);
284	vec_ro = ev_malloc (sizeof (fd_set));
285	vec_wi = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_wi);
286	vec_wo = ev_malloc (sizeof (fd_set));
287	#ifdef _WIN32
288	vec_eo = ev_malloc (sizeof (fd_set));
289	#endif
290	#else
291	vec_max = 0;
292	vec_ri = 0;
293	vec_ro = 0;
294	vec_wi = 0;
295	vec_wo = 0;
296	#ifdef _WIN32
297	vec_eo = 0;
298	#endif
299	#endif
300
301	return EVBACKEND_SELECT;
302	}
303
304	inline_size
305	void
306	select_destroy (EV_P)
307	{
308	ev_free (vec_ri);
309	ev_free (vec_ro);
310	ev_free (vec_wi);
311	ev_free (vec_wo);
312	#ifdef _WIN32
313	ev_free (vec_eo);
314	#endif
315	}
316