123 lines
3.1 KiB
C++
123 lines
3.1 KiB
C++
/* poll.cc. Implements poll(2) via usage of select(2) call.
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Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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Red Hat, Inc.
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This file is part of Cygwin.
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This software is a copyrighted work licensed under the terms of the
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Cygwin license. Please consult the file "CYGWIN_LICENSE" for
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details. */
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#define __INSIDE_CYGWIN_NET__
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#define FD_SETSIZE 16384 // lots of fds
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#include "winsup.h"
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#include <sys/poll.h>
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#include <stdlib.h>
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#define USE_SYS_TYPES_FD_SET
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#include "cygerrno.h"
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#include "path.h"
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#include "fhandler.h"
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#include "dtable.h"
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#include "cygheap.h"
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extern "C" int
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poll (struct pollfd *fds, nfds_t nfds, int timeout)
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{
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int max_fd = 0;
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fd_set *read_fds, *write_fds, *except_fds;
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struct timeval tv = { timeout / 1000, (timeout % 1000) * 1000 };
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for (unsigned int i = 0; i < nfds; ++i)
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if (fds[i].fd > max_fd)
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max_fd = fds[i].fd;
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size_t fds_size = howmany (max_fd + 1, NFDBITS) * sizeof (fd_mask);
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read_fds = (fd_set *) alloca (fds_size);
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write_fds = (fd_set *) alloca (fds_size);
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except_fds = (fd_set *) alloca (fds_size);
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if (!read_fds || !write_fds || !except_fds)
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{
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set_errno (EINVAL); /* According to SUSv3. */
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return -1;
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}
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memset (read_fds, 0, fds_size);
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memset (write_fds, 0, fds_size);
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memset (except_fds, 0, fds_size);
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int invalid_fds = 0;
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for (unsigned int i = 0; i < nfds; ++i)
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{
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fds[i].revents = 0;
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if (!cygheap->fdtab.not_open (fds[i].fd))
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{
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if (fds[i].events & POLLIN)
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FD_SET(fds[i].fd, read_fds);
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if (fds[i].events & POLLOUT)
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FD_SET(fds[i].fd, write_fds);
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if (fds[i].events & POLLPRI)
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FD_SET(fds[i].fd, except_fds);
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}
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else if (fds[i].fd >= 0)
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{
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++invalid_fds;
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fds[i].revents = POLLNVAL;
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}
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}
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if (invalid_fds)
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return invalid_fds;
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int ret = cygwin_select (max_fd + 1, read_fds, write_fds, except_fds,
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timeout < 0 ? NULL : &tv);
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if (ret <= 0)
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return ret;
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/* Set revents fields and count fds with non-zero revents fields for
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return value. */
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ret = 0;
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for (unsigned int i = 0; i < nfds; ++i)
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{
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if (fds[i].fd >= 0)
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{
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if (cygheap->fdtab.not_open (fds[i].fd))
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fds[i].revents = POLLHUP;
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else
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{
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fhandler_socket *sock;
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if (FD_ISSET(fds[i].fd, read_fds))
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/* This should be sufficient for sockets, too. Using
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MSG_PEEK, as before, can be considered dangerous at
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best. Quote from W. Richard Stevens: "The presence
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of an error can be considered either normal data or
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an error (POLLERR). In either case, a subsequent read
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will return -1 with errno set to the appropriate value."
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So it looks like there's actually no good reason to
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return POLLERR. */
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fds[i].revents |= POLLIN;
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/* Handle failed connect. */
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if (FD_ISSET(fds[i].fd, write_fds)
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&& (sock = cygheap->fdtab[fds[i].fd]->is_socket ())
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&& sock->connect_state () == connect_failed)
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fds[i].revents |= (POLLIN | POLLERR);
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else
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{
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if (FD_ISSET(fds[i].fd, write_fds))
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fds[i].revents |= POLLOUT;
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if (FD_ISSET(fds[i].fd, except_fds))
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fds[i].revents |= POLLPRI;
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}
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}
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if (fds[i].revents)
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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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