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Date:	Sun, 2 Feb 2003 18:37:34 -0800
Mime-Version:	1.0 (Apple Message framework v551)
Subject:	1.3.19-1:poll bug. Patch included.
From:	Peter Rehley <peter AT rehley DOT net>
To:	cygwin AT cygwin DOT com
Message-Id:	<7374AB6B-3720-11D7-B5F3-00306540AD5E@rehley.net>

Hello,

While working on another program (syslogd in inetutils) I found that 
the poll function was returning POLLERR when something arrived on a UDP 
socket; it should be return POLLIN.  Inside the poll function, recvfrom 
was returning -1 with errno = EMSGSIZE, but the only error value being 
check for in WSAENOTCONN.  However EMSGSIZE is a reasonable return 
value since the buffer to recvfrom was only 1 byte while the actual 
message size was larger than this.  Basically saying your buffer is too 
small for the message, but since we are only peeking, this shouldn't be 
returned as a POLLERR.

The fix should be to add EMSGSIZE as part of the condition so this 
error returns POLLIN.  I'm including the patch below and a changelog 
following that.  Please review these changes and make sure that they 
seem reasonable.  I've done tests on my system (windows XP) and have 
verified that the change works.

Patch
-----------------------------------
Index: winsup/cygwin/poll.cc
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/poll.cc,v
retrieving revision 1.34
diff -u -p -r1.34 poll.cc
--- winsup/cygwin/poll.cc	20 Nov 2002 11:00:15 -0000	1.34
+++ winsup/cygwin/poll.cc	3 Feb 2003 01:52:10 -0000
@@ -112,7 +112,8 @@ poll (struct pollfd *fds, unsigned int n
  				 sense then.  It returns WSAENOTCONN in that
  				 case.  Since that's not actually an error,
  				 we must not set POLLERR but POLLIN. */
-			      if (WSAGetLastError () != WSAENOTCONN)
+			      if (WSAGetLastError () != WSAENOTCONN &&
+				  errno!=EMSGSIZE)
  				fds[i].revents |= POLLERR;
  			      else
  				fds[i].revents |= POLLIN;
----------------------
Changelog
2003-02-02  Peter Rehley<peter AT rehley DOT net>

* poll.cc: EMSGSIZE being ignore returning incorrect POLLERR on UDP 
socket receive
  if recvfrom returns error, return POLLIN if errno = EMSGSIZE
-----------------------

Peter
=====
Infinity Softworks.  Making scientific, financial and realtor 
calculators for Palm Pilots and other PDAs since 1997

Visit them today at http://www.infinitysw.com


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