(#8210) Add a heavy virtual fact using virt-what

Without this patch facter does not return kvm when running inside of an
enterprise linux guest VM hosted on an enterprise linux kvm host.

This is a problem because facter improperly reports the virtual machine
is actually running on physical hardware, which is not true.  This
causes downstream problems for anyone relying on the virtual fact being
accurate.

This patch fixes the problem by adding a new resolver for the virtual
fact that has a very high weight.  The new resolver calls `virt-what`,
available on Enterprise Linux machines by installing the `virt-what`
package.  The last line of output is used to determine the virtual
machine hypervisor type.

If virt-what is not available or returns no output, then existing lower
weight resolvers are used instead.

lib/facter/util/virtual.rb

@@ -1,4 +1,19 @@
 module Facter::Util::Virtual
+  ##
+  # virt_what is a delegating helper method intended to make it easier to stub
+  # the system call without affecting other calls to
+  # Facter::Util::Resolution.exec
+  def self.virt_what(command = "virt-what")
+    Facter::Util::Resolution.exec command
+  end
+
+  ##
+  # lspci is a delegating helper method intended to make it easier to stub the
+  # system call without affecting other calls to Facter::Util::Resolution.exec
+  def self.lspci(command = "lspci 2>/dev/null")
+    Facter::Util::Resolution.exec command
+  end
+
   def self.openvz?
     FileTest.directory?("/proc/vz") and not self.openvz_cloudlinux?
   end

lib/facter/virtual.rb

@@ -89,7 +89,7 @@
     end
 
     if result == "physical"
-      output = Facter::Util::Resolution.exec('lspci 2>/dev/null')
+      output = Facter::Util::Virtual.lspci
       if not output.nil?
         output.each_line do |p|
           # --- look for the vmware video card to determine if it is virtual => vmware.
@@ -153,6 +153,39 @@
   end
 end
 
+##
+# virtual fact based on virt-what command.
+#
+# The output is mapped onto existing known values for the virtual fact in an
+# effort to preserve consistency.  This fact has a high weight becuase the
+# virt-what tool is expected to be maintained upstream.
+#
+# If the virt-what command is not available, this fact will not resolve to a
+# value and lower-weight virtual facts will be attempted.
+#
+# Only the last line of the virt-what command is returned
+Facter.add("virtual") do
+  has_weight 500
+
+  setcode do
+    output = Facter::Util::Virtual.virt_what
+    case output
+    when 'linux_vserver'
+      Facter::Util::Virtual.vserver_type
+    when /xen-hvm/i
+      'xenhvm'
+    when /xen-dom0/i
+      'xen0'
+    when /xen-domU/i
+      'xenu'
+    when /ibm_systemz/i
+      'zlinux'
+    else
+      output.to_s.split("\n").last
+    end
+  end
+end
+
 # Fact: is_virtual
 #
 # Purpose: returning true or false for if a machine is virtualised or not.

spec/unit/virtual_spec.rb

@@ -13,6 +13,7 @@
     Facter::Util::Virtual.stubs(:kvm?).returns(false)
     Facter::Util::Virtual.stubs(:hpvm?).returns(false)
     Facter::Util::Virtual.stubs(:zlinux?).returns(false)
+    Facter::Util::Virtual.stubs(:virt_what).returns(nil)
   end
 
   it "should be zone on Solaris when a zone" do
@@ -82,13 +83,13 @@
 
     it "should be parallels with Parallels vendor id from lspci 2>/dev/null" do
       Facter.fact(:kernel).stubs(:value).returns("Linux")
-      Facter::Util::Resolution.stubs(:exec).with('lspci 2>/dev/null').returns("01:00.0 VGA compatible controller: Unknown device 1ab8:4005")
+      Facter::Util::Virtual.stubs(:lspci).returns("01:00.0 VGA compatible controller: Unknown device 1ab8:4005")
       Facter.fact(:virtual).value.should == "parallels"
     end
 
     it "should be parallels with Parallels vendor name from lspci 2>/dev/null" do
       Facter.fact(:kernel).stubs(:value).returns("Linux")
-      Facter::Util::Resolution.stubs(:exec).with('lspci 2>/dev/null').returns("01:00.0 VGA compatible controller: Parallels Display Adapter")
+      Facter::Util::Virtual.stubs(:lspci).returns("01:00.0 VGA compatible controller: Parallels Display Adapter")
       Facter.fact(:virtual).value.should == "parallels"
     end
 
@@ -233,6 +234,39 @@
       Facter.fact(:virtual).value.should == "xenhvm"
     end
   end
+
+  describe "with the virt-what command available (#8210)" do
+    describe "when the output of virt-what disagrees with lower weight facts" do
+      virt_what_map = {
+        'xen-hvm'  => 'xenhvm',
+        'xen-dom0' => 'xen0',
+        'xen-domU' => 'xenu',
+        'ibm_systemz' => 'zlinux',
+      }
+
+      virt_what_map.each do |input,output|
+        it "maps #{input} to #{output}" do
+          Facter::Util::Virtual.expects(:virt_what).returns(input)
+          Facter.value(:virtual).should == output
+        end
+      end
+    end
+
+    describe "arbitrary outputs of virt-what" do
+      it "returns the last line output from virt-what" do
+        Facter::Util::Virtual.expects(:virt_what).returns("one\ntwo\nthree space\n")
+        Facter.value(:virtual).should == "three space"
+      end
+    end
+
+    describe "when virt-what returns linux_vserver" do
+      it "delegates to Facter::Util::Virtual.vserver_type" do
+        Facter::Util::Virtual.expects(:virt_what).returns("linux_vserver")
+        Facter::Util::Virtual.expects(:vserver_type).returns("fake_vserver_type")
+        Facter.value(:virtual).should == "fake_vserver_type"
+      end
+    end
+  end
 end
 
 describe "is_virtual fact" do