Report the correct result if the "server" service is not running

[jviotti]

If the "server" service is not running, this module will report false
even when the user is the administrator.

By investigating further, net.exe session fails with the following
message:

The Server service is not started.

More help is available by typing NET HELPMSG 2114.

which is caught by the .catch() block, which returns false without
inspecting the error object.

The main issue is that net.exe session returns an exit code 2 both
when the user has no permissions and when the server service is not
running, making it impossibly to distinguish between both scenarios
without inspecting the output of the command.

The StackOverflow question linked from the source code addresses this
concern in another answer, by proposing the use of the following
command:

fsutil dirty query %systemdrive% >nul

fsutil is ensured to be present on Windows XP and later, and returns
an exit code 0 if the user is the administrator, and exit code 1
otherwise.

This commit introduces the recommended fsutil command, and falls back
to an fltmc approach discussed on the same thread if fsutil doesn't
exist (e.g: we get ENOENT for it).

Fixes: #3
See: http://stackoverflow.com/a/21295806/1641422
Signed-off-by: Juan Cruz Viotti jviotti@openmailbox.org

[lurch]

#3 (comment)

AIUI it'd be better to fall back to sfc if fsutil isn't available, because net session is still just as likely to fail?

[jviotti]

Up to @sindresorhus. I'm happy with both approaches.

[jviotti]

Ping @sindresorhus

[sindresorhus]

Sorry, too many PRs to deal with.

AIUI it'd be better to fall back to sfc if fsutil isn't available, because net session is still just as likely to fail?

👍

[jviotti]

@sindresorhus @lurch Turns out the sfc approach doesn't work on any of my Windows systems (I get an error level 1 even when I'm an admin). The same thread discussed yet another approach, based on fltmc, which seems to work fine for me, so I added that one as a fallback instead.

[sindresorhus]

Thanks :)