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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2010, Digium, Inc.
*
* Tilghman Lesher <tlesher AT digium DOT com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*!\file
* \brief Bitfield expansions for ast_select
*/
#ifndef __AST_SELECT_H
#define __AST_SELECT_H
#include <sys/select.h>
#include <errno.h>
#include "asterisk/utils.h"
#ifdef __cplusplus
extern "C" {
#endif
extern unsigned int ast_FD_SETSIZE;
#if !defined(HAVE_VARIABLE_FDSET) && defined(CONFIGURE_RAN_AS_ROOT)
#define ast_fdset fd_set
#else
typedef struct {
long fds_bits[4096 / sizeof(long)]; /* 32768 bits */
} ast_fdset;
#undef FD_ZERO
#define FD_ZERO(a) \
do { \
long *bytes = (long *) a; \
int i; \
for (i = 0; i < sizeof(*(a)) / sizeof(long); i++) { \
bytes[i] = 0; \
} \
} while (0)
#undef FD_SET
#define FD_SET(fd, fds) \
do { \
long *bytes = (long *) fds; \
if (fd / sizeof(*bytes) + ((fd + 1) % sizeof(*bytes) ? 1 : 0) < sizeof(*(fds))) { \
bytes[fd / (sizeof(*bytes))] |= 1L << (fd % sizeof(*bytes)); \
} else { \
ast_log(LOG_ERROR, "FD %d exceeds the maximum size of ast_fdset!\n", fd); \
} \
} while (0)
#endif /* HAVE_VARIABLE_FDSET */
/*! \brief Waits for activity on a group of channels
* \param nfds the maximum number of file descriptors in the sets
* \param rfds file descriptors to check for read availability
* \param wfds file descriptors to check for write availability
* \param efds file descriptors to check for exceptions (OOB data)
* \param tvp timeout while waiting for events
* This is the same as a standard select(), except it guarantees the
* behaviour where the passed struct timeval is updated with how much
* time was not slept while waiting for the specified events
*/
static inline int ast_select(int nfds, ast_fdset *rfds, ast_fdset *wfds, ast_fdset *efds, struct timeval *tvp)
{
#ifdef __linux__
ast_assert((unsigned int) nfds <= ast_FD_SETSIZE);
return select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, tvp);
#else
int save_errno = 0;
ast_assert((unsigned int) nfds <= ast_FD_SETSIZE);
if (tvp) {
struct timeval tv, tvstart, tvend, tvlen;
int res;
tv = *tvp;
gettimeofday(&tvstart, NULL);
res = select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, tvp);
save_errno = errno;
gettimeofday(&tvend, NULL);
timersub(&tvend, &tvstart, &tvlen);
timersub(&tv, &tvlen, tvp);
if (tvp->tv_sec < 0 || (tvp->tv_sec == 0 && tvp->tv_usec < 0)) {
tvp->tv_sec = 0;
tvp->tv_usec = 0;
}
errno = save_errno;
return res;
}
else
return select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, NULL);
#endif
}
#ifdef __cplusplus
}
#endif
#endif /* __AST_SELECT_H */
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