Message-ID: <47E42B1E.8010300@mit.edu>
Date: Fri, 21 Mar 2008 15:39:42 -0600
From: Jeffrey Altman <jaltman@mit.edu>
User-Agent: Thunderbird 2.0.0.12 (Windows/20080213)
MIME-Version: 1.0
To: rt@krbdev.mit.edu
Subject: Re: [krbdev.mit.edu #5925] Windows socket(...) returns SOCKET,	not file handle
References: <rt-5925-26226.9.26167509446572@krbdev.mit.edu>
In-Reply-To: <rt-5925-26226.9.26167509446572@krbdev.mit.edu>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Reply-To: jaltman@mit.edu
RT-Send-Cc: 
Content-Length: 872

Kevin Koch via RT wrote:
> sendto_kdc.c start_connection(...) calls socket(...).  
> 
> The returned SOCKET is treated as a file handle.
> 
> On Windows, the SOCKET is greater than FD_SETSIZE, so close is called.  
> The SOCKET is also greater than the number of file handles, so close 
> asserts.

(1) close() is a C Runtime Library function that only works on C RTL 
file descriptors.   closesocket() must be used for SOCKET returned by 
socket().

(2) FD_SETSIZE in winsock has no relation to the value of SOCKET 
handles.   FD_SETSIZE is the number of sockets that can be stored in an 
fd_set.  It is not a maximum bound on the value of the handle.

Arrays of FD_SETSIZE are not safe to use on Windows.  Alternative data 
structures must be designed that will work on all platforms including 
UNIX/Linux systems whose "ulimit -n" values are raised above FD_SETSIZE.