150 lines
3.9 KiB
C++
150 lines
3.9 KiB
C++
/* poll.cc. Implements poll(2) via usage of select(2) call.
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Copyright 2000, 2001, 2002, 2003, 2004, 2005 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/time.h>
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#include <sys/poll.h>
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#include <sys/socket.h>
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#include <stdlib.h>
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#define USE_SYS_TYPES_FD_SET
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#include <winsock2.h>
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#include "cygerrno.h"
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#include "security.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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#include "sigproc.h"
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extern "C" int
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poll (struct pollfd *fds, unsigned int 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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/* On sockets, except_fds is needed to catch failed connects. */
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if ((fds[i].events & POLLPRI)
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|| cygheap->fdtab[fds[i].fd]->is_socket ())
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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, timeout < 0 ? NULL : &tv);
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if (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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{
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char peek[1];
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sock = cygheap->fdtab[fds[i].fd]->is_socket ();
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if (!sock)
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fds[i].revents |= POLLIN;
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else
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{
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/* The following action can change errno. We have to
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reset it to it's old value. */
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int old_errno = get_errno ();
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switch (sock->recvfrom (peek, sizeof (peek), MSG_PEEK,
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NULL, NULL))
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{
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case -1: /* Something weird happened */
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/* When select returns that data is available,
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that could mean that the socket is in
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listen mode and a client tries to connect.
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Unfortunately, recvfrom() doesn't make much
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sense then. It returns WSAENOTCONN in that
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case. Since that's not actually an error,
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we must not set POLLERR but POLLIN. */
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if (WSAGetLastError () != WSAENOTCONN)
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fds[i].revents |= POLLERR;
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else
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fds[i].revents |= POLLIN;
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break;
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case 0: /* Closed on the read side. */
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fds[i].revents |= POLLHUP;
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break;
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default:
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fds[i].revents |= POLLIN;
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break;
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}
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set_errno (old_errno);
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}
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}
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/* Handle failed connect. */
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if (FD_ISSET(fds[i].fd, write_fds)
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&& FD_ISSET(fds[i].fd, except_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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}
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}
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return ret;
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}
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