guests/freebsd: Configure hostname in a single command

This updates freebsd to set the hostname in a single command and prepend
the hostname to the /etc/hosts file.

plugins/guests/freebsd/cap/change_host_name.rb

@@ -3,9 +3,27 @@ module VagrantPlugins
     module Cap
       class ChangeHostName
         def self.change_host_name(machine, name)
-          if !machine.communicate.test("hostname -f | grep '^#{name}$' || hostname -s | grep '^#{name}$'", {shell: "sh"})
-            machine.communicate.sudo("sed -i '' 's/^hostname=.*$/hostname=\"#{name}\"/' /etc/rc.conf", {shell: "sh"})
-            machine.communicate.sudo("hostname #{name}", {shell: "sh"})
+          options = { shell: "sh" }
+          comm = machine.communicate
+
+          if !comm.test("hostname -f | grep -w '#{name}' || hostname -s | grep -w '#{name}'", options)
+            basename = name.split(".", 2)[0]
+            command = <<-EOH.gsub(/^ {14}/, '')
+              # Set the hostname
+              hostname '#{name}'
+              sed -i '' 's/^hostname=.*$/hostname=\"#{name}\"/' /etc/rc.conf
+
+              # Remove comments and blank lines from /etc/hosts
+              sed -i'' -e 's/#.*$//' /etc/hosts
+              sed -i'' -e '/^$/d' /etc/hosts
+
+              # Prepend ourselves to /etc/hosts
+              grep -w '#{name}' /etc/hosts || {
+                echo -e '127.0.0.1\\t#{name}\\t#{basename}' | cat - /etc/hosts > /tmp/tmp-hosts
+                mv /tmp/tmp-hosts /etc/hosts
+              }
+            EOH
+            comm.sudo(command, options)
           end
         end
       end

test/unit/plugins/guests/freebsd/cap/change_host_name_test.rb

@@ -0,0 +1,40 @@
+require_relative "../../../../base"
+
+describe "VagrantPlugins::GuestFreeBSD::Cap::ChangeHostName" do
+  let(:described_class) do
+    VagrantPlugins::GuestFreeBSD::Plugin
+      .components
+      .guest_capabilities[:freebsd]
+      .get(:change_host_name)
+  end
+
+  let(:machine) { double("machine") }
+  let(:comm) { VagrantTests::DummyCommunicator::Communicator.new(machine) }
+
+  before do
+    allow(machine).to receive(:communicate).and_return(comm)
+  end
+
+  after do
+    comm.verify_expectations!
+  end
+
+  describe ".change_host_name" do
+    let(:name) { "banana-rama.example.com" }
+
+    it "sets the hostname and /etc/hosts" do
+      comm.stub_command("hostname -f | grep -w '#{name}' || hostname -s | grep -w '#{name}'", exit_code: 1)
+      described_class.change_host_name(machine, name)
+
+      expect(comm.received_commands[1]).to match(/hostname '#{name}'/)
+      expect(comm.received_commands[1]).to match(/grep -w '#{name}' \/etc\/hosts/)
+      expect(comm.received_commands[1]).to match(/echo -e '127.0.0.1\\t#{name}\\tbanana-rama'/)
+    end
+
+    it "does nothing if the hostname is already set" do
+      comm.stub_command("hostname -f | grep -w '#{name}' || hostname -s | grep -w '#{name}'", exit_code: 0)
+      described_class.change_host_name(machine, name)
+      expect(comm.received_commands.size).to eq(1)
+    end
+  end
+end