98 lines
2.8 KiB
C
98 lines
2.8 KiB
C
/*
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* Copyright (c) 2013, 2016, 2017 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* sys/select/select.c
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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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#include <string.h>
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static const int READ_EVENTS = POLLIN | POLLRDNORM | POLLERR | POLLHUP;
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static const int WRITE_EVENTS = POLLOUT | POLLWRNORM | POLLERR;
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static const int EXCEPT_EVENTS = POLLERR | POLLHUP;
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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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fds[fds_count].events |= READ_EVENTS;
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if ( writefds && FD_ISSET(i, writefds) )
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fds[fds_count].events |= WRITE_EVENTS;
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if ( exceptfds && FD_ISSET(i, exceptfds) )
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fds[fds_count].events |= EXCEPT_EVENTS;
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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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size_t fd_bytes = ((size_t) nfds + 7) / 8;
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if ( readfds )
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memset(readfds, 0, fd_bytes);
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if ( writefds )
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memset(writefds, 0, fd_bytes);
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if ( exceptfds )
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memset(exceptfds, 0, fd_bytes);
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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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