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libev/ev_select.c

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/*
* 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 (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 (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 = timeout * 1e3;
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 (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_mintime = 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;
}
void inline_size
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
}
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