Hi Heikki,

On Mon, Feb 16, 2026 at 09:51:00AM +0200, Heikki Linnakangas wrote:
> On 15/02/2026 10:11, Michael Banck wrote:
> > On Tue, Oct 08, 2024 at 12:55:00AM +0300, Heikki Linnakangas wrote:
> > > In the meanwhile, here is a one more version of the test patches, with a
> > > SKIP that checks that IO::Socket::UNIX works.
> > 
> > I've only realized recently, but those postmaster tap tests have been
> > failing during Debian package build (see e.g. [0]) on hurd-i386/amd64 with
> > 
> > |send: Cannot determine peer address at t/002_connection_limits.pl line 136.
> > 
> > This wasn't widely noticed because both architectures are on the (not
> > small) list of arches where test suite failures are ignored[1] but I
> > think nowadays it is the only (or one of the very few) remaining
> > issue(s). I encountered it now when I tried to turn on
> > --enable-tap-tests on fruitcrow.
> > 
> > The Perl code run through strace shows it runs connect(), then
> > getpeername() and then sendto(), as seen here[2]. However, getpeername()
> > on Unix sockets is not implemented on the Hurd yet[3] (granted, FSVO
> > "yet", the issue is 20 years old). I've opened an issue in Perl asking
> > to work around this here: https://github.com/Perl/perl5/issues/24195
> > 
> > Would something like the attached be acceptable in the interim to have
> > this test be skipped on the Hurd as well?
> 
> Hmm, so is the "$sock->send('foo');" actually necessary, if the error occurs
> on getpeername() already? Where does the getpeername() call come from?

I wasn't very clear in my last message, this is the send() code in Perl
(see https://github.com/Perl/perl5/blob/blead/dist/IO/lib/IO/Socket.pm#L294):

|sub send {
|    @_ >= 2 && @_ <= 4 or croak 'usage: $sock->send(BUF, [FLAGS, [TO]])';
|    my $sock  = $_[0];
|    my $flags = $_[2] || 0;
|    my $peer;
|
|    if ($_[3]) {
|        # the caller explicitly requested a TO, so use it
|        # this is non-portable for "connected" UDP sockets
|        $peer = $_[3];
|    }
|    elsif (!defined getpeername($sock)) {
|        # we're not connected, so we require a peer from somewhere
|        $peer = $sock->peername;
|
|       croak 'send: Cannot determine peer address'
|           unless(defined $peer);
|    }
|
|    my $r = $peer
|      ? send($sock, $_[1], $flags, $peer)
|      : send($sock, $_[1], $flags);
|
|    # remember who we send to, if it was successful
|    ${*$sock}{'io_socket_peername'} = $peer
|       if(@_ == 4 && defined $r);
|
|    $r;
|}

So if we don't give send() a third argument, it runs getpeername() on
the socket. I have the feeling it is unncessary to require a peer for
local Unix sockets and have suggested that now in the Perl issue.

> It would be nice to silence that failure one way or another. If we go with
> this approach, would need a comment at least to explain it.
 
Right.

> It seems a little awkward to send garbage to the server for this. Could we
> replace the send() with a non-blocking recv() or something?

I am not quite sure how this would look like?


Thanks,

Michael


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