Support running Vagrant within the Windows Subsystem for Linux

bin/vagrant

@@ -112,6 +112,13 @@ begin
     argv += argv_extra
   end
 
+  # If we are running with the Windows Subsystem for Linux do
+  # some extra setup to allow access to Vagrant managed machines
+  # outside the subsystem
+  if Vagrant::Util::Platform.wsl?
+    Vagrant::Util::Platform.wsl_init(logger)
+  end
+
   # Create the environment, which is the cwd of wherever the
   # `vagrant` command was invoked from
   logger.debug("Creating Vagrant environment")

lib/vagrant/errors.rb

@@ -780,6 +780,10 @@ module Vagrant
       error_key(:vboxmanage_not_found_error)
     end
 
+    class VBoxManageNotFoundWSLError < VagrantError
+      error_key(:vboxmanage_not_found_wsl_error)
+    end
+
     class VirtualBoxBrokenVersion040214 < VagrantError
       error_key(:virtualbox_broken_version_040214)
     end

lib/vagrant/util/platform.rb

@@ -28,6 +28,27 @@ module Vagrant
           return @_cygwin
         end
 
+        def wsl?
+          if !defined?(@_wsl)
+            @_wsl = false
+            original_verbose = $VERBOSE
+            begin
+              $VERBOSE = nil
+              # Use PATH values to check for `/mnt/c` path indicative of WSL
+              if ENV.fetch("PATH", "").downcase.include?("/mnt/c")
+                # Validate WSL via uname output
+                uname = Subprocess.execute("uname", "-r")
+                if uname.exit_code == 0 && uname.stdout.downcase.include?("microsoft")
+                  @_wsl = true
+                end
+              end
+            ensure
+              $VERBOSE = original_verbose
+            end
+          end
+          @_wsl
+        end
+
         [:darwin, :bsd, :freebsd, :linux, :solaris].each do |type|
           define_method("#{type}?") do
             platform.include?(type.to_s)
@@ -223,6 +244,72 @@ module Vagrant
           return @_platform
         end
 
+        # Determine if given path is within the WSL rootfs. Returns
+        # true if within the subsystem, or false if outside the subsystem.
+        #
+        # @param [String] path Path to check
+        # @return [Boolean] path is within subsystem
+        def wsl_path?(path)
+          wsl? && !path.to_s.downcase.start_with?("/mnt/")
+        end
+
+        # Allow Vagrant to access Vagrant managed machines outside the
+        # Windows Subsystem for Linux
+        #
+        # @return [Boolean]
+        def wsl_windows_access?
+          if !defined?(@_wsl_windows_access)
+            @_wsl_windows_access = wsl? && ENV["VAGRANT_WSL_ACCESS_WINDOWS_USER"]
+          end
+          @_wsl_windows_access
+        end
+
+        # The allowed windows system path Vagrant can manage from the Windows
+        # Subsystem for Linux
+        #
+        # @return [Pathname]
+        def wsl_windows_accessible_path
+          if !defined?(@_wsl_windows_accessible_path)
+            access_path = ENV.fetch("VAGRANT_WSL_ACCESS_WINDOWS_USER_HOME_PATH",
+              "/mnt/c/Users/#{ENV["VAGRANT_WSL_ACCESS_WINDOWS_USER"]}")
+            @_wsl_windows_accessible_path = Pathname.new(access_path)
+          end
+          @_wsl_windows_accessible_path
+        end
+
+        # Checks given path to determine if Vagrant is allowed to bypass checks
+        #
+        # @param [String] path Path to check
+        # @return [Boolean] Vagrant is allowed to bypass checks
+        def wsl_windows_access_bypass?(path)
+          wsl? && wsl_windows_access? &&
+            path.to_s.start_with?(wsl_windows_accessible_path.to_s)
+        end
+
+        # If running within the Windows Subsystem for Linux, this will provide
+        # simple setup to allow sharing of the user's VAGRANT_HOME directory
+        # within the subsystem
+        #
+        # @param [Logger] logger Optional logger to display information
+        def wsl_init(logger=nil)
+          if wsl? && ENV["VAGRANT_WSL_ACCESS_WINDOWS_USER"]
+            shared_user = ENV["VAGRANT_WSL_ACCESS_WINDOWS_USER"]
+            if logger
+              logger.warn("Windows Subsystem for Linux detected. Allowing access to user: #{shared_user}")
+              logger.warn("Vagrant will be allowed to control Vagrant managed machines within the user's home path.")
+            end
+            if ENV["VAGRANT_HOME"] || ENV["VAGRANT_WSL_DISABLE_VAGRANT_HOME"]
+              logger.warn("VAGRANT_HOME environment variable already set. Not overriding!") if logger
+            else
+              home_path = wsl_windows_accessible_path
+              ENV["VAGRANT_HOME"] = File.join(home_path, ".vagrant.d")
+              if logger
+                logger.info("Overriding VAGRANT_HOME environment variable to configured windows user. (#{ENV["VAGRANT_HOME"]})")
+              end
+            end
+          end
+        end
+
         # @private
         # Reset the cached values for platform. This is not considered a public
         # API and should only be used for testing.

lib/vagrant/util/ssh.rb

@@ -28,7 +28,7 @@ module Vagrant
       def self.check_key_permissions(key_path)
         # Don't do anything if we're on Windows, since Windows doesn't worry
         # about key permissions.
-        return if Platform.windows?
+        return if Platform.windows? || Platform.wsl_windows_access_bypass?(key_path)
 
         LOGGER.debug("Checking key permissions: #{key_path}")
         stat = key_path.stat

plugins/providers/virtualbox/driver/base.rb

@@ -66,6 +66,12 @@ module VagrantPlugins
                 break
               end
             end
+          elsif Vagrant::Util::Platform.wsl?
+            @logger.debug("Linux platform detected but executing within WSL. Locating VBoxManage.")
+            @vboxmanage_path = Vagrant::Util::Which.which("VBoxManage") || Vagrant::Util::Which.which("VBoxManage.exe")
+            if !@vboxmanage_path
+              raise Vagrant::Errors::VBoxManageNotFoundWSLError
+            end
           end
 
           # Fall back to hoping for the PATH to work out

plugins/providers/virtualbox/provider.rb

@@ -84,11 +84,15 @@ module VagrantPlugins
       def state
         # We have to check if the UID matches to avoid issues with
         # VirtualBox.
-        uid = @machine.uid
-        if uid && uid.to_s != Process.uid.to_s
-          raise Vagrant::Errors::VirtualBoxUserMismatch,
-            original_uid: uid.to_s,
-            uid: Process.uid.to_s
+        if Vagrant::Util::Platform.wsl_windows_access_bypass?(@machine.data_dir)
+          @logger.warn("Skipping UID check on machine by user request for WSL Windows access.")
+        else
+          uid = @machine.uid
+          if uid && uid.to_s != Process.uid.to_s
+            raise Vagrant::Errors::VirtualBoxUserMismatch,
+              original_uid: uid.to_s,
+              uid: Process.uid.to_s
+          end
         end
 
         # Determine the ID of the state here.

templates/locales/en.yml

@@ -1381,6 +1381,16 @@ en:
         log out and log back in for the new environmental variables to take
         effect. If you're on Linux or Mac, verify your PATH contains the folder
         that has VBoxManage in it.
+      vboxmanage_not_found_wsl_error: |-
+        The "VBoxManage.exe" command or one of its dependencies could not
+        be found. Please verify VirtualBox is properly installed. You can verify
+        everything is okay by running "VBoxManage.exe --version" and verifying
+        that the VirtualBox version is outputted.
+
+        If you just installed VirtualBox, you have to log out and log back in for
+        the new environmental variables to take effect. Using the VirtualBox
+        provider within the WSL requires VirtualBox executables to be available
+        on the system PATH.
       virtualbox_broken_version_040214: |-
         Vagrant detected you have VirtualBox 4.2.14 installed. VirtualBox
         4.2.14 contains a critical bug which prevents it from working with