python fails asyncio tests (py 3.7 & 3.8)
Mark Geisert
mark@maxrnd.com
Thu Dec 3 06:57:33 GMT 2020
[replying to myself.. sorry..]
On Wed, 2 Dec 2020, Mark Geisert wrote:
> Hi Corinna,
>
> On Wed, 2 Dec 2020, Corinna Vinschen wrote:
> [...]
>>
>> This is apparently an old problem in the still current AF_LOCAL
>> implementation. Christian Franke encountered it when porting postfix:
>>
>> https://sourceware.org/legacy-ml/cygwin/2014-08/msg00420.html
>>
>> The problem is the security handshake between listening/accepting socket
>> and connecting socket. The connecting socket send its half of the
>> handshake and waits for accept on the other side to return the other
>> half. However, if the listening side doesn't accept right away, the
>> connecting side hangs.
>>
>> The workaround right now is to call
>>
>> int peercred_off = 1;
>> fd = socket (AF_LOCAL, SOCK_STREAM, 0);
>> setsockopt(fd, SOL_SOCKET, SO_PEERCRED, &peercred_off, sizeof
>> peercred_off);
>>
>> This disables the security handshake.
>
> I see. For this problem report should the setsockopt() workaround be applied
> to Python (yikes!) or can it be done for all apps at once in
> fhandler_socket_local::socket()? I might be able to look into the standing
> issue with the security handshake later on, if (my) time permits. I
> appreciate the history/explanation on this.
> Thanks & Regards,
>
> ..mark
Putting the workaround in fhandler_socket_local::socket() compiles fine
and the OP's Python testing issue seems fixed. OTOH XWin and X apps exit
soon after starting so that's no bueno.
It looks like the individual Python tests that exhibit the problem are
going to need patching. Does that sound about right?
Thanks again,
..mark
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