113 lines
3.1 KiB
C
113 lines
3.1 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 2010, Digium, Inc.
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*
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* Tilghman Lesher <tlesher AT digium DOT com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*!\file
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* \brief Bitfield expansions for ast_select
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*/
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#ifndef __AST_SELECT_H
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#define __AST_SELECT_H
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#include <sys/time.h>
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#include <sys/select.h>
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#include <errno.h>
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#include "asterisk/compat.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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extern unsigned int ast_FD_SETSIZE;
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#if !defined(HAVE_VARIABLE_FDSET) && defined(CONFIGURE_RAN_AS_ROOT)
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#define ast_fdset fd_set
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#else
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#define ast_FDMAX 32768
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typedef struct {
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TYPEOF_FD_SET_FDS_BITS fds_bits[ast_FDMAX / 8 / SIZEOF_FD_SET_FDS_BITS]; /* 32768 bits */
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} ast_fdset;
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#define _bitsize(a) (sizeof(a) * 8)
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#undef FD_ZERO
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#define FD_ZERO(a) \
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do { \
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TYPEOF_FD_SET_FDS_BITS *bytes = (TYPEOF_FD_SET_FDS_BITS *) a; \
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int i; \
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for (i = 0; i < ast_FDMAX / _bitsize(TYPEOF_FD_SET_FDS_BITS); i++) { \
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bytes[i] = 0; \
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} \
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} while (0)
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#undef FD_SET
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#define FD_SET(fd, fds) \
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do { \
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TYPEOF_FD_SET_FDS_BITS *bytes = (TYPEOF_FD_SET_FDS_BITS *) fds; \
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if (fd < ast_FDMAX) { \
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bytes[fd / _bitsize(*bytes)] |= ((TYPEOF_FD_SET_FDS_BITS) 1) << (fd % _bitsize(*bytes)); \
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} else { \
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fprintf(stderr, "FD %d exceeds the maximum size of ast_fdset!\n", fd); \
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} \
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} while (0)
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#endif /* HAVE_VARIABLE_FDSET */
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/*! \brief Waits for activity on a group of channels
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* \param nfds the maximum number of file descriptors in the sets
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* \param rfds file descriptors to check for read availability
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* \param wfds file descriptors to check for write availability
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* \param efds file descriptors to check for exceptions (OOB data)
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* \param tvp timeout while waiting for events
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* This is the same as a standard select(), except it guarantees the
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* behaviour where the passed struct timeval is updated with how much
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* time was not slept while waiting for the specified events
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*/
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static inline int ast_select(int nfds, ast_fdset *rfds, ast_fdset *wfds, ast_fdset *efds, struct timeval *tvp)
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{
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#ifdef __linux__
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return select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, tvp);
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#else
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int save_errno = 0;
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if (tvp) {
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struct timeval tv, tvstart, tvend, tvlen;
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int res;
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tv = *tvp;
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gettimeofday(&tvstart, NULL);
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res = select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, tvp);
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save_errno = errno;
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gettimeofday(&tvend, NULL);
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timersub(&tvend, &tvstart, &tvlen);
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timersub(&tv, &tvlen, tvp);
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if (tvp->tv_sec < 0 || (tvp->tv_sec == 0 && tvp->tv_usec < 0)) {
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tvp->tv_sec = 0;
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tvp->tv_usec = 0;
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}
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errno = save_errno;
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return res;
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}
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else
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return select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, NULL);
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#endif
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* __AST_SELECT_H */
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