setsockopt with SO_LINGER returns EINVAL

[nmeocisco]

• Your Windows build number: 10.0.17763.437

• What you're doing and what's happening: I was trying to setup osquery under WSL to duplicate a development environment I currently have inside an Ubuntu 18.04 VM. It appears to have a problem with configuring sockets which hinders full functionality. The osquery package used in Ubuntu 18.04 under WSL can be obtained from here:

https://pkg.osquery.io/deb/osquery_3.3.2_1.linux.amd64.deb

Once installed I run the following command:

/usr/bin/osqueryd --extensions_socket=/tmp/osquery.em -logger_path=/tmp/osqueryd_log --database_path=/tmp/osqueryd_db --pidfile=/tmp/osqueryd.pid --force=true --disable_watchdog --disable_events=false --events_expiry=3600 --events_max=50000

Among the messages displayed on start will be the following:

W0423 14:31:57.658298 149 interface.cpp:269] Extensions disabled: cannot start extension manager (/tmp/osquery.em) (Could not set SO_LINGER: Invalid argument)

• What's wrong / what should be happening instead: The /tmp/osquery.em domain socket does not get created as a result of this failure. The SO_LINGER with setsockopt should succeed.

• Strace of the failing command, if applicable: Inside my Ubuntu 18.04 VM where this works fine the strace is as follows:

socket(AF_UNIX, SOCK_STREAM, 0) = 14
setsockopt(14, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
setsockopt(14, SOL_SOCKET, SO_LINGER, {l_onoff=0, l_linger=0}, 8) = 0

The strace of the failure inside WSL with Ubuntu 18.04 is as follows:

socket(AF_UNIX, SOCK_STREAM, 0) = 11
setsockopt(11, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
setsockopt(11, SOL_SOCKET, SO_LINGER, {l_onoff=0, l_linger=0}, 8) = -1 EINVAL (Invalid argument)

[therealkenc]

Was able to reproduce; not a dupe AFAICT. Guess SO_LINGER isn't supported with WSL's AF_UNIX. Not too surprised it never came up before since lingering around on a IPC socket is "unusual". I think (?) it might make sense in some esoteric cases. Anyway, Real Linux eats it. Probably suffice to just no-op on WSL, in a pinch.

Oddly I couldn't find it in the osquery source. Maybe it's buried down below in a library. But if you can find the line of code and just comment it out, it'll probably work fine. Probably.

// g++ linger.cpp &&  strace ./a.out
#include <sys/types.h>
#include <sys/socket.h>
int main(int argc, const char *argv[])
{
    struct linger l = {};
    int sd = socket(AF_UNIX, SOCK_STREAM, 0);
    setsockopt(sd, SOL_SOCKET, SO_LINGER, &l, sizeof(l));
    return 0;
}

[microsoft-github-policy-service]

This issue has been automatically closed since it has not had any activity for the past year. If you're still experiencing this issue please re-file this as a new issue or feature request.

Thank you!