Enable WinSSH shell for `vagrant ssh -c` (#11258)

This commit changes the behavior of the builtin SSHRun action to use a Windows
shell if the WinSSH communicator is active.  This allows for running one-off SSH
commands with Windows Command Prompt or PowerShell.  By default, this will not
allocate a TTY for any SSH commands.

Example usage:

```
vagrant ssh -c 'dir "c:\program files"'
```

Updates docs to reflect a change made in
a55a53e6a4.

lib/vagrant/action/builtin/ssh_run.rb

@@ -36,17 +36,35 @@ module Vagrant
 
           # Get the command and wrap it in a login shell
           command = ShellQuote.escape(env[:ssh_run_command], "'")
-          command = "#{env[:machine].config.ssh.shell} -c '#{command}'"
+
+          if env[:machine].config.vm.communicator == :winssh
+            shell = env[:machine].config.winssh.shell
+          else
+            shell = env[:machine].config.ssh.shell
+          end
+
+          if shell == "cmd"
+            # Add an extra space to the command so cmd.exe quoting works
+            # properly
+            command = "#{shell} /C #{command} "
+          elsif shell == "powershell"
+            command = "$ProgressPreference = \"SilentlyContinue\"; #{command}"
+            command = Base64.strict_encode64(command.encode("UTF-16LE", "UTF-8"))
+            command = "#{shell} -encodedCommand #{command}"
+          else
+            command = "#{shell} -c '#{command}'"
+          end
 
           # Execute!
           opts = env[:ssh_opts] || {}
           opts[:extra_args] ||= []
 
           # Allow the user to specify a tty or non-tty manually, but if they
-          # don't then we default to a TTY
+          # don't then we default to a TTY unless they are using WinSSH
           if !opts[:extra_args].include?("-t") &&
               !opts[:extra_args].include?("-T") &&
-              env[:tty]
+              env[:tty] &&
+              env[:machine].config.vm.communicator != :winssh
             opts[:extra_args] << "-t"
           end
 

test/unit/vagrant/action/builtin/ssh_run_test.rb

@@ -18,8 +18,14 @@ describe Vagrant::Action::Builtin::SSHRun do
     )
   end
 
+  let(:vm) do
+    double("vm",
+      communicator: nil
+    )
+  end
+
   # Configuration mock
-  let(:config) { double("config", ssh: ssh) }
+  let(:config) { double("config", ssh: ssh, vm: vm) }
 
   let(:machine) do
     double("machine",
@@ -80,4 +86,63 @@ describe Vagrant::Action::Builtin::SSHRun do
     env[:ssh_run_command] = "echo test"
     described_class.new(app, env).call(env)
   end
+
+  context "when using the WinSSH communicator" do
+    let(:winssh) { double("winssh", shell: "foo") }
+
+    before do
+      expect(vm).to receive(:communicator).and_return(:winssh)
+      expect(config).to receive(:winssh).and_return(winssh)
+      env[:tty] = nil
+    end
+
+    it "should use the WinSSH shell for running ssh commands" do
+      ssh_info = { foo: :bar }
+      opts = {:extra_args=>["foo -c 'dir'"], :subprocess=>true}
+
+      expect(ssh_klass).to receive(:exec).
+        with(ssh_info, opts)
+
+      env[:ssh_info] = ssh_info
+      env[:ssh_run_command] = "dir"
+      described_class.new(app, env).call(env)
+    end
+
+    context "when shell is cmd" do
+      before do
+        expect(winssh).to receive(:shell).and_return('cmd')
+      end
+
+      it "should use appropriate options for cmd" do
+        ssh_info = { foo: :bar }
+        opts = {:extra_args=>["cmd /C dir "], :subprocess=>true}
+
+        expect(ssh_klass).to receive(:exec).
+          with(ssh_info, opts)
+
+        env[:ssh_info] = ssh_info
+        env[:ssh_run_command] = "dir"
+        described_class.new(app, env).call(env)
+      end
+    end
+
+    context "when shell is powershell" do
+      before do
+        expect(winssh).to receive(:shell).and_return('powershell')
+      end
+
+      it "should base64 encode the command" do
+        ssh_info = { foo: :bar }
+        encoded_command = "JABQAHIAbwBnAHIAZQBzAHMAUAByAGUAZgBlAHIAZQBuAGMAZQAgAD0AIAAiAFMAaQBsAGUAbgB0AGwAeQBDAG8AbgB0AGkAbgB1AGUAIgA7ACAAZABpAHIA"
+        opts = {:extra_args=>["powershell -encodedCommand #{encoded_command}"], :subprocess=>true}
+
+        expect(ssh_klass).to receive(:exec).
+          with(ssh_info, opts)
+
+        env[:ssh_info] = ssh_info
+        env[:ssh_run_command] = "dir"
+        described_class.new(app, env).call(env)
+      end
+    end
+  end
 end

website/source/docs/vagrantfile/ssh_settings.html.md

@@ -126,9 +126,7 @@ net-ssh library (ignored by the `ssh` executable) and should not be used in gene
 This defaults to the value of `config.ssh.username`.
 
 * `config.ssh.shell` (string) - The shell to use when executing SSH commands from
-Vagrant. By default this is `bash -l`. Note that this has no effect on
-the shell you get when you run `vagrant ssh`. This configuration option
-only affects the shell to use when executing commands internally in Vagrant.
+Vagrant. By default this is `bash -l`.
 
 * `config.ssh.sudo_command` (string) - The command to use when executing a command
 with `sudo`. This defaults to `sudo -E -H %c`. The `%c` will be replaced by

website/source/docs/vagrantfile/winssh_settings.html.md

@@ -48,9 +48,7 @@ packets every 5 seconds by default to keep connections alive.
 
 * `config.winssh.shell` (string) - The shell to use when executing SSH commands from
 Vagrant. By default this is `cmd`. Valid values are `"cmd"` or `"powershell"`.
-Note that this has no effect on the shell you get when you run `vagrant ssh`.
-This configuration option only affects the shell to use when executing commands
-internally in Vagrant.
+When the WinSSH provider is enabled, this shell will be used when you run `vagrant ssh`.
 
 * `config.winssh.export_command_template` (string) - The template used to generate
 exported environment variables in the active session. This can be useful