Prepend computer name to user when created scheduled tasks

When running a shell provisioner elevated with winrm a scheduled
task is created to bypass permissions issues. If the name of the
computer has changed this may no longer work. To prevent errors
this PR updates the implementation to fetch the computer name
and prepends it to the username before creating the task.

plugins/communicators/winrm/shell.rb

@@ -71,7 +71,13 @@ module VagrantPlugins
       def elevated(command, opts = {}, &block)
         connection.shell(:elevated) do |shell|
           shell.interactive_logon = opts[:interactive] || false
-          execute_with_rescue(shell, command, &block)
+          uname = shell.username
+          begin
+            shell.username = elevated_username
+            execute_with_rescue(shell, command, &block)
+          ensure
+            shell.username = uname
+          end
         end
       end
 
@@ -216,6 +222,24 @@ module VagrantPlugins
           retry_delay: @config.retry_delay,
           retry_limit: @config.max_tries }
       end
+
+      def elevated_username
+        if @elevated_username
+          return @elevated_username
+        end
+        if username.include?("\\")
+          return @elevated_username = username
+        end
+        computername = ""
+        powershell("Write-Output $env:computername") do |type, data|
+          computername << data if type == :stdout
+        end
+        computername.strip!
+        if computername.empty?
+          return @elevated_username = username
+        end
+        @elevated_username = "#{computername}\\#{username}"
+      end
     end #WinShell class
   end
 end

test/unit/plugins/communicators/winrm/shell_test.rb

@@ -75,6 +75,14 @@ describe VagrantPlugins::CommunicatorWinRM::WinRMShell do
   end
 
   describe ".elevated" do
+    let(:username) { double("username") }
+
+    before do
+      allow(subject).to receive(:elevated_username).and_return(username)
+      allow(shell).to receive(:username).and_return(username)
+      allow(shell).to receive(:username=)
+    end
+
     it "should call winrm elevated" do
       expect(shell).to receive(:run).with("dir").and_return(output)
       expect(shell).to receive(:interactive_logon=).with(false)
@@ -93,6 +101,13 @@ describe VagrantPlugins::CommunicatorWinRM::WinRMShell do
       expect { subject.powershell("dir") }.to raise_error(
         VagrantPlugins::CommunicatorWinRM::Errors::ExecutionError)
     end
+
+    it "should use elevated username" do
+      expect(subject).to receive(:elevated_username).and_return(username)
+      expect(shell).to receive(:run).with("dir").and_return(output)
+      expect(shell).to receive(:interactive_logon=).with(false)
+      expect(subject.elevated("dir").exitcode).to eq(0)
+    end
   end
 
   describe ".cmd" do
@@ -178,4 +193,41 @@ describe VagrantPlugins::CommunicatorWinRM::WinRMShell do
     end
   end
 
+  describe "#elevated_username" do
+    let(:username) { "username" }
+
+    before do
+      allow(subject).to receive(:username).and_return(username)
+      allow(subject).to receive(:powershell)
+    end
+
+    it "should return username" do
+      expect(subject.send(:elevated_username)).to eq(username)
+    end
+
+    it "should attempt to get computer name" do
+      expect(subject).to receive(:powershell).with(/computername/)
+      subject.send(:elevated_username)
+    end
+
+    it "should prepend computer name when available" do
+      expect(subject).to receive(:powershell).with(/computername/).and_yield(:stdout, "COMPUTERNAME")
+      expect(subject.send(:elevated_username)).to eq("COMPUTERNAME\\#{username}")
+    end
+
+    it "should only compute elevated username once" do
+      expect(subject).to receive(:powershell).once.with(/computername/).and_yield(:stdout, "COMPUTERNAME")
+      expect(subject.send(:elevated_username)).to eq("COMPUTERNAME\\#{username}")
+      expect(subject.send(:elevated_username)).to eq("COMPUTERNAME\\#{username}")
+    end
+
+    context "when username includes computer/domain name" do
+      let(:username) { "machine\\username" }
+
+      it "should not attempt to get computer name" do
+        expect(subject).not_to receive(:powershell)
+        expect(subject.send(:elevated_username)).to eq(username)
+      end
+    end
+  end
 end