From 8b7e501e50ad15a4da2b6d4bff47236e44f4f48a Mon Sep 17 00:00:00 2001
From: Chris Roberts <croberts@hashicorp.com>
Date: Wed, 28 Feb 2018 10:06:15 -0800
Subject: [PATCH] Handle pathing in lxrun generated WSL instances better.

---
 lib/vagrant/util/platform.rb            | 18 ++++++--
 test/unit/vagrant/util/platform_test.rb | 61 ++++++++++++++++++++++++-
 2 files changed, 74 insertions(+), 5 deletions(-)

diff --git a/lib/vagrant/util/platform.rb b/lib/vagrant/util/platform.rb
index c8f8fa7b9..7f0d6f039 100644
--- a/lib/vagrant/util/platform.rb
+++ b/lib/vagrant/util/platform.rb
@@ -305,7 +305,8 @@ module Vagrant
             logger = Log4r::Logger.new("vagrant::util::platform::wsl")
 
             # Check for lxrun installation first
-            paths = [[wsl_windows_appdata_local, "lxss"].join("\\")]
+            lxrun_path = [wsl_windows_appdata_local, "lxss"].join("\\")
+            paths = [lxrun_path]
 
             logger.debug("checking registry for WSL installation path")
             paths += PowerShell.execute_cmd(
@@ -363,6 +364,11 @@ module Vagrant
             raise Vagrant::Errors::WSLRootFsNotFoundError if @_wsl_rootfs.nil?
           end
 
+          # Attach the rootfs leaf to the path
+          if @_wsl_rootfs != lxrun_path
+            @_wsl_rootfs = "#{@_wsl_rootfs}\\rootfs"
+          end
+
           logger.debug("detected `#{@_wsl_rootfs}` as current WSL instance")
 
           @_wsl_rootfs
@@ -375,11 +381,17 @@ module Vagrant
         # @param [String, Pathname] path Path to convert
         # @return [String]
         def wsl_to_windows_path(path)
-          if wsl? && wsl_windows_access?
+          if wsl? && wsl_windows_access? && !path.match(/^[a-zA-Z]:/)
             if wsl_path?(path)
               parts = path.split("/")
               parts.delete_if(&:empty?)
-              [wsl_rootfs, *parts].join("\\")
+              root_path = wsl_rootfs
+              # lxrun splits home separate so we need to account
+              # for it's specialness here when we build the path
+              if root_path.end_with?("lxss") && parts.first != "home"
+                root_path = "#{root_path}\\rootfs"
+              end
+              [root_path, *parts].join("\\")
             else
               path = path.to_s.sub("/mnt/", "")
               parts = path.split("/")
diff --git a/test/unit/vagrant/util/platform_test.rb b/test/unit/vagrant/util/platform_test.rb
index ba3cf17be..8b4046188 100644
--- a/test/unit/vagrant/util/platform_test.rb
+++ b/test/unit/vagrant/util/platform_test.rb
@@ -281,12 +281,69 @@ describe Vagrant::Util::Platform do
 
           it "should return the matching path" do
             expect(Dir).to receive(:open).with(/#{matching_part}/).and_yield(double("path", path: matching_part))
-            expect(subject.wsl_rootfs).to eq(matching_path)
+            expect(subject.wsl_rootfs).to start_with(matching_path)
           end
 
           it "should return matching path when access error encountered" do
             expect(Dir).to receive(:open).with(/#{matching_part}/).and_raise(Errno::EACCES)
-            expect(subject.wsl_rootfs).to eq(matching_path)
+            expect(subject.wsl_rootfs).to start_with(matching_path)
+          end
+        end
+      end
+    end
+
+    describe ".wsl_to_windows_path" do
+      let(:path){ "/home/vagrant/test" }
+
+      context "when not within WSL" do
+        before{ allow(subject).to receive(:wsl?).and_return(false) }
+
+        it "should return the path unmodified" do
+          expect(subject.wsl_to_windows_path(path)).to eq(path)
+        end
+      end
+
+      context "when within WSL" do
+        before{ allow(subject).to receive(:wsl?).and_return(true) }
+
+        context "when windows access is not enabled" do
+          before{ allow(subject).to receive(:wsl_windows_access?).and_return(false) }
+
+          it "should return the path unmodified" do
+            expect(subject.wsl_to_windows_path(path)).to eq(path)
+          end
+        end
+
+        context "when windows access is enabled" do
+          let(:rootfs_path){ "C:\\WSL\\rootfs" }
+
+          before do
+            allow(subject).to receive(:wsl_windows_access?).and_return(true)
+            allow(subject).to receive(:wsl_rootfs).and_return(rootfs_path)
+          end
+
+          it "should generate expanded path when within WSL" do
+            expect(subject.wsl_to_windows_path(path)).to eq("#{rootfs_path}#{path.gsub("/", "\\")}")
+          end
+
+          it "should generate direct path when outside the WSL" do
+            expect(subject.wsl_to_windows_path("/mnt/c/vagrant")).to eq("c:\\vagrant")
+          end
+
+          it "should not modify path when already in windows format" do
+            expect(subject.wsl_to_windows_path("C:\\vagrant")).to eq("C:\\vagrant")
+          end
+
+          context "when within lxrun generated WSL instance" do
+            let(:rootfs_path){ "C:\\WSL\\lxss" }
+
+            it "should not include rootfs when accessing home" do
+              expect(subject.wsl_to_windows_path("/home/vagrant")).not_to include("rootfs")
+            end
+
+            it "should include rootfs when accessing non-home path" do
+              expect(subject.wsl_to_windows_path("/tmp/test")).to include("rootfs")
+            end
           end
         end
       end