120 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			120 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			C++
		
	
	
	
| /* poll.cc. Implements poll(2) via usage of select(2) call.
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| 
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|    Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006 Red Hat, Inc.
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| 
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|    This file is part of Cygwin.
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| 
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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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| 
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| #define  __INSIDE_CYGWIN_NET__
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| 
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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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| 
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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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| 
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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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| 
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|   size_t fds_size = howmany (max_fd + 1, NFDBITS) * sizeof (fd_mask);
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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|   if (invalid_fds)
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|     return invalid_fds;
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| 
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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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| 
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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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| 
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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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| 	  }
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|       }
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| 
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|   return ret;
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| }
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