allow_superuser false blocks non admin user in Windows

[kaisecheng]

Setting allow_superuser: false is expected to run Logstash successfully with non admin user. However, on Windows, Logstash exits with an error even when the user is not an admin.

The issue occurs because Process.euid() always returns 0 in Windows.

Relates: #14089
cc @mashhurs

[donoghuc]

Puppet and Vagrant are both projects that require detecting this. Here are some ways they have approached it.

Puppet uses ffi to avoid WMI
This however is quite complex and requires ffi

https://github.com/puppetlabs/puppet/blob/e758d5c969403631810fa6385057ef0eaf03974f/lib/puppet/util/windows/user.rb#L11

Vagrant used to use WMI
Below is an example of how that looks, we could potentially cache these calls etc but it is probably going to be fraught with peril.

    running_process = WIN32OLE.connect("winmgmts://")
    process_id = Process.pid
    process = running_process.ExecQuery("Select * from Win32_Process where ProcessId = #{process_id}")
    owner = process.each.first.GetOwner

    # Check if the user is in the administrators group
    admin_group = running_process.ExecQuery("Select * from Win32_Group where LocalAccount = True and SID = 'S-1-5-32-544'")
    group_users = running_process.ExecQuery("Select * from Win32_GroupUser where GroupComponent = 'Win32_Group.Name=\"#{admin_group.each.first.Name}\",Domain=\"#{owner[1]}\"'")
    
    group_users.each do |user|
      return true if user.PartComponent.include?(owner[0])
    end
    false

Vagrant used to use registry keys

See this iteration hashicorp/vagrant@52e98ff where they replace looking up registry keys. Given that PR i'm not convinced this is the best path forward

Now Vagrant shells out to powershell:

If shelling out is acceptable here we could avoid gem dependencies and probably get the most accurate data. This however assumes we can reliably find a powershell executable.
https://github.com/hashicorp/vagrant/blob/e0161e5b0de4200001062342fb2b742acc2b7ea3/lib/vagrant/util/platform.rb#L103-L113