mirror of
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104 lines
2.9 KiB
C++
104 lines
2.9 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013, 2016.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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sys/select/select.cpp
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Waiting on multiple file descriptors.
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*******************************************************************************/
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#include <sys/select.h>
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#include <errno.h>
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#include <poll.h>
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static const int READ_EVENTS = POLLIN | POLLRDNORM;
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static const int WRITE_EVENTS = POLLOUT | POLLWRNORM;
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static const int EXCEPT_EVENTS = POLLERR | POLLHUP;
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extern "C"
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int select(int nfds, fd_set* restrict readfds, fd_set* restrict writefds,
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fd_set* restrict exceptfds, struct timeval* restrict timeout)
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{
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if ( nfds < 0 || FD_SETSIZE < nfds )
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return errno = EINVAL, -1;
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if ( timeout )
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{
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if ( timeout->tv_sec < 0 )
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return errno = EINVAL, -1;
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if ( timeout->tv_usec < 0 || 1000000 <= timeout->tv_usec )
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return errno = EINVAL, -1;
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}
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struct pollfd fds[FD_SETSIZE];
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nfds_t fds_count = 0;
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for ( int i = 0; i < nfds; i++ )
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{
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fds[fds_count].fd = i;
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fds[fds_count].events = fds[fds_count].revents = 0;
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if ( readfds && FD_ISSET(i, readfds) )
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{
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FD_CLR(i, readfds);
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fds[fds_count].events |= READ_EVENTS;
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}
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if ( writefds && FD_ISSET(i, writefds) )
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{
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FD_CLR(i, writefds);
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fds[fds_count].events |= WRITE_EVENTS;
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}
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if ( exceptfds && FD_ISSET(i, exceptfds) )
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{
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FD_CLR(i, exceptfds);
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fds[fds_count].events |= EXCEPT_EVENTS;
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}
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if ( fds[fds_count].events )
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fds_count++;
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}
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struct timespec* timeout_tsp = NULL;
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struct timespec timeout_ts;
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if ( timeout )
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{
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timeout_tsp = &timeout_ts;
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timeout_tsp->tv_sec = timeout->tv_sec;
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timeout_tsp->tv_nsec = (long) timeout->tv_usec * 1000L;
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}
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int num_occur = ppoll(fds, fds_count, timeout_tsp, NULL);
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if ( num_occur < 0 )
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return -1;
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int ret = 0;
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for ( nfds_t i = 0; i < fds_count; i++ )
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{
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int fd = fds[i].fd;
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int events = fds[i].revents;
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if ( events & READ_EVENTS && readfds )
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{
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FD_SET(fd, readfds);
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ret++;
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}
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if ( events & WRITE_EVENTS && writefds )
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{
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FD_SET(fd, writefds);
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ret++;
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}
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if ( events & EXCEPT_EVENTS && exceptfds )
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{
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FD_SET(fd, exceptfds);
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ret++;
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}
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}
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return ret;
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}
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