Unix sockets are not implemented

[guineawheek]

socket() works, but bind() doesn't create the actual socket file.
This kills things like wine and ssh-agent.

[SvenGroot]

Unix sockets are partially implemented, and they do work. The socket files just don't show up in the file system. However, it's still possible to connect to them if you know the path of the socket file. Of course, this does break applications that attempt to "stat" a socket file or do anything else that depends on the file being present.

We're working to address this issue.

[sunilmut]

As Sven Groot (@SvenGroot) mentions, file system integration of UNIX sockets is not complete yet. We will be tracking\prioritizing which features to light up next by looking at the feedback provided at the wpdev portal. We appreciate your feedback and please make sure to provide it through the wpdev portal as well.

[MadcowD]

Sven Groot (@SvenGroot) Sunil Muthuswamy (@sunilmut) Just an update I can reproduce the issue referenced with #1331. Jupyter notebook is using sockets and getting Invalid argument (src/tcp_address.cpp:186). Further investigation led me to find that
libzmq is not currently working with BashOnWindows.

I built libzmq and got the following log from the test suite. All of the errors point to the same line of code.
test-suite.txt
In particular, this is the code which is causing an invalid argument error. See getifaddrs.

#elif ((defined ZMQ_HAVE_LINUX || defined ZMQ_HAVE_FREEBSD ||\
    defined ZMQ_HAVE_OSX || defined ZMQ_HAVE_OPENBSD ||\
    defined ZMQ_HAVE_QNXNTO || defined ZMQ_HAVE_NETBSD ||\
    defined ZMQ_HAVE_DRAGONFLY || defined ZMQ_HAVE_GNU)\
    && defined ZMQ_HAVE_IFADDRS)

#include <ifaddrs.h>

//  On these platforms, network interface name can be queried
//  using getifaddrs function.
int zmq::tcp_address_t::resolve_nic_name (const char *nic_, bool ipv6_, bool is_src_)
{
    //  Get the addresses.
    ifaddrs *ifa = NULL;
    const int rc = getifaddrs (&ifa);
    errno_assert (rc == 0);
    zmq_assert (ifa != NULL);

    //  Find the corresponding network interface.
    bool found = false;
    for (ifaddrs *ifp = ifa; ifp != NULL; ifp = ifp->ifa_next) {
        if (ifp->ifa_addr == NULL)
            continue;

        const int family = ifp->ifa_addr->sa_family;
        if ((family == AF_INET || (ipv6_ && family == AF_INET6))
        && !strcmp (nic_, ifp->ifa_name)) {
            if (is_src_)
                memcpy (&source_address, ifp->ifa_addr,
                        (family == AF_INET) ? sizeof (struct sockaddr_in)
                                            : sizeof (struct sockaddr_in6));
            else
                memcpy (&address, ifp->ifa_addr,
                        (family == AF_INET) ? sizeof (struct sockaddr_in)
                                            : sizeof (struct sockaddr_in6));
            found = true;
            break;
        }
    }

    //  Clean-up;
    freeifaddrs (ifa);

    if (!found) {
        errno = ENODEV;
        return -1;
    }
    return 0;
}

Related #69

[benhillis]

Adding link to source code exhibiting an issue: #207

[lypanov]

This AFAICT also breaks Rails 5 out of the box without the hack of disabling of spring (it's simply too slow at times without Spring so this is really painful). Any news on this?

[mindplay-dk]

This may be what's breaking the default socket-based configuration with NGINX and PHP-FPM? I was able to get it to run reliably only after configuring it to use TCP instead of sockets, and also failed to use sockets with PHP, is this all related to this issue?

Is there a fix on the way, or is this very far off? I really want to use UOW for development on my Windows system, mainly because there are features (such as sockets, threads and readline support) that are unavailable in Windows-builds of PHP.

[aseering]

Could someone on the WSL team perhaps summarize what they believe to be the status of this issue?

I have personally used UNIX Sockets without any issue. But I haven't done anything fancy with them. I realize it's more complicated than a simple "works" vs "not works" -- there are lots of flags and options and whatnot that you can set on a socket that affect its behavior; my understanding is that some work and some do not.

[sunilmut]

Adam Seering (@aseering) - We are not aware of any open issues with the WSL AF_UNIX socket implementation. But, I know it's not fully compatible yet because for example the dbus test does not give the same results as that of native Ubuntu. We haven't dug into all the failures yet. We are trying to prioritize issues reported here as they come.

Rasmus Schultz (@mindplay-dk) - Thanks for your post. We will have to take one issue at a time, so that we can root cause and fix it. Can you please post repro steps, build number and strace, if possible? You can see the template here. To gather strace, use strace -o <trace_file> -ff <cmd>

[aseering]

Regarding capturing an strace, the challenge here will presumably be identifying what command to run. (The "command" in this case is two separate backgrounded system services, nginx and php-fpm; both would need to be run directly and in the foreground.) Rasmus Schultz (@mindplay-dk) -- I think you indicated on #1851 that you weren't sure how to accomplish that level of Linux magic? I can try to take a look, but I may not get to it for a while. If anyone else is following this thread and would be willing to give it a shot, please do.

[aseering]

Sunil Muthuswamy (@sunilmut) -- thanks! The title of this ticket implies that UNIX sockets don't work at all. And the ticket is still open. Up to you, but I wonder if some ticket-wrangling might be in order? :-)

[sunilmut]

Adam Seering (@aseering) - Makes sense. I will close this issue out, it's too broad and not actionable. Rasmus Schultz (@mindplay-dk) - We will continue to work with you on the other issue.

As for the strace, we would have to then rely on the repro.