[1.7] IPv6 accept() fails if address_len is < sizeof(sockaddr_in6) [was Re: PATCH /usr/include/X11/Xtrans/Xtranssock.c [WAS: Re: xhost package not compiled for IPv6]]

[Corinna Vinschen]

On Aug 12 14:48, Jon TURNEY wrote:
> On 12/08/2009 13:54, Jon TURNEY wrote:
>> Hmmm... but if it's really the size of the sockname argument which is
>> causing the accept() to fail, this would be a bug in cygwin's accept()
>> implementation, as it's supposed to truncate the data written to the
>> sockname, rather than fail if it won't fit [1]. If that actually is the
>> case, since we don't actually use the peer address here, the code as
>> stands is correct (if a little odd).
>>
>> I suppose I need to write a small test case to look at this...
>>
>> [1] http://www.opengroup.org/onlinepubs/009695399/functions/accept.html
>
> A couple of small programs which hopefully demonstrate this problem.
>
> (As is, the connection fails, but uncommenting the alternate definition 
> of cliaddr in listener.c allows it to work)
>
> I'd hazard a guess that perhaps this is because the underlying winsock  
> accept() doesn't have this truncate behaviour and considers a too-small  
> address_len an error.

Thanks for the testcase!  This confirms what I wrote about WinSock in
http://cygwin.com/ml/cygwin-xfree/2009-08/msg00029.html

Now for the patch to workaround that problem...


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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