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/* poll.cc. Implements poll(2) via usage of select(2) call.
Copyright 2000, 2001 Red Hat, Inc.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include "winsup.h"
#include <sys/time.h>
#include <sys/poll.h>
#include <errno.h>
#include "security.h"
#include "fhandler.h"
#include "path.h"
#include "dtable.h"
#include "cygerrno.h"
#include "cygheap.h"
#include "sigproc.h"
extern "C"
int
poll (struct pollfd *fds, unsigned int nfds, int timeout)
{
int max_fd = 0;
fd_set *open_fds, *read_fds, *write_fds, *except_fds;
struct timeval tv = { timeout / 1000, (timeout % 1000) * 1000 };
sigframe thisframe (mainthread);
for (unsigned int i = 0; i < nfds; ++i)
if (fds[i].fd > max_fd)
max_fd = fds[i].fd;
size_t fds_size = howmany(max_fd + 1, NFDBITS) * sizeof (fd_mask);
open_fds = (fd_set *) alloca (fds_size);
read_fds = (fd_set *) alloca (fds_size);
write_fds = (fd_set *) alloca (fds_size);
except_fds = (fd_set *) alloca (fds_size);
if (!open_fds || !read_fds || !write_fds || !except_fds)
{
set_errno (ENOMEM);
return -1;
}
memset (open_fds, 0, fds_size);
memset (read_fds, 0, fds_size);
memset (write_fds, 0, fds_size);
memset (except_fds, 0, fds_size);
bool invalid_fds = false;
for (unsigned int i = 0; i < nfds; ++i)
if (!cygheap->fdtab.not_open (fds[i].fd))
{
FD_SET (fds[i].fd, open_fds);
if (fds[i].events & POLLIN)
FD_SET (fds[i].fd, read_fds);
if (fds[i].events & POLLOUT)
FD_SET (fds[i].fd, write_fds);
if (fds[i].events & POLLPRI)
FD_SET (fds[i].fd, except_fds);
}
else
invalid_fds = true;
int ret = 0;
if (!invalid_fds)
ret = cygwin_select (max_fd + 1, read_fds, write_fds, except_fds,
timeout < 0 ? NULL : &tv);
for (unsigned int i = 0; i < nfds; ++i)
{
if (!FD_ISSET (fds[i].fd, open_fds))
{
fds[i].revents = POLLNVAL;
ret++;
}
else if (cygheap->fdtab.not_open(fds[i].fd))
fds[i].revents = POLLHUP;
else if (ret < 0)
fds[i].revents = POLLERR;
else
{
fds[i].revents = 0;
if (FD_ISSET (fds[i].fd, read_fds))
fds[i].revents |= POLLIN;
if (FD_ISSET (fds[i].fd, write_fds))
fds[i].revents |= POLLOUT;
if (FD_ISSET (fds[i].fd, except_fds))
fds[i].revents |= POLLPRI;
}
}
return ret;
}
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