Provide a way to positively detect WSL from an app compiled on Linux.

[dmiller-nmap]

I understand that support is always improving, but it seems unlikely that the specific network functionality (raw sockets, packet sniffing, netlink routes) required by Nmap will ever be supported in WSL/BashOnWindows. We would like to be able to detect WSL and provide users with a helpful message pointing them to our Windows-native build, while allowing our app to continue until the first crash/error.

Is there any stable, predictable method for detecting whether our built-on-Linux program is being run on Windows Subsystem for Linux?

[therealkenc]

Can't speculate on 'stable', but /proc/version has the string 'Microsoft' which seems a pretty safe bet.

[benhillis]

@therealkenc For the time being this is probably the best way to do it. I can't promise that we'll never change the content of these ProcFs files, but I think it's unlikely we'll change it to something that doesn't contain "Microsoft" or "WSL".

/proc/sys/kernel/osrelease
/proc/version

[fpqc]

@benhillis Do you guys over at Microsoft think you might ever support any/most/all of this low-level functionality used by nmap, eventually, in the (distant) future? Are there reasons in principle why you wouldn't want to or couldn't realistically support them?

[benhillis]

@fpqc There's a lot of surface areas and features to cover in limited time. The best way to help us prioritize work is by adding items to our User Voice page.

[fpqc]

@benhillis Yes absolutely you only have a limited time before the Anniversary update for Win10. I was just asking if the team over at Microsoft is planning on eventually seeing the project through to something on which the whole of the Linux userland can run (albeit maybe sometimes requiring tweaks). I mean, of course, Microsoft is a business, not a charity, and ultimately development will continue only if WSL meets business goals, but I was just asking whether the current plan is that development will continue by the WSL team improving compatibility for the foreseeable future.

I think WSL is really Windows 10's new "Killer App" (to use some cliched marketing lingo), and I personally know several people already who have moved (or are prepared to move) back to a Windows ecosystem from Linux because it's such an exciting project.

My biggest worry is that MS is going to take the project to something like 85% completion and then let it stagnate. WSL is something for which I would be willing to pay and for which my company would also be willing to pay, so I hope that development will continue past the anniversary release.

[benhillis]

@fpqc This question is definitely above my pay-grade but I'll try to answer as best I can.

I will say that as a developer on this feature I'm excited about the future of the project don't see it stagnating any time soon. We have some exciting things planned that make me optimistic about the future of our technology.

Thank you for your kind words. I'm sorry if I'm being somewhat vague but I'm trying to err on the side of not putting my foot in my mouth :)

[benhillis]

Closing this out since the discussion has run its course.