Re: Unix Domain Socket Limitation?

[Ken Brown <kbrown@cornell.edu>]

[Adding the Cygwin list back to the Cc.]

On 11/26/2020 11:27 AM, Norton Allen wrote:
> On 11/25/2020 5:27 PM, Ken Brown via Cygwin wrote:
>> On 11/25/2020 4:47 PM, Norton Allen wrote:
>>> In my recent tests, it appears as though it is not possible to successfully 
>>> connect via two Unix Domain sockets from one client application to one server 
>>> application.
>>>
>>> Specifically, if I create a server which listens on a Unix Domain socket and 
>>> a client, which attempts to connect() twice, both seem to lock up. This is 
>>> not the behavior under Linux.
>>>
>>> I will be happy to work up a minimal example if it is helpful in tracking 
>>> this down. I wanted to start by asking whether this is a known limitation 
>>> and/or if there is something about the Cygwin implementation that makes this 
>>> sort of thing very difficult.
>>
>> A minimal example would be extremely helpful.
>>
>> Corinna can answer questions about limitations in the current implementation. 
>> But there is a new implementation under development. It's in the topic/af_unix 
>> branch of the Cygwin git repository if you're interested in looking at it.
>>
>> Corinna began working on this a couple years ago, and I've recently been 
>> trying to finish it.  I've made quite a bit of progress, but there's still 
>> more to do and undoubtedly many bugs. So any test cases you have would be very 
>> useful. 
> 
> Thanks Ken,
> 
> As it happens, attempting to produce a minimal example suggests my problem may 
> be somewhere else. I think I've worked in most of the features of my application 
> one by one but have not yet revealed a failure.

OK.  But if you ever do have occasion to write small test programs involving 
AF_UNIX sockets, please send them on.  The new AF_UNIX code needs as much 
testing as it can get.

Ken