add function is_virtual to distro/FreeBSD (#1957)

- is_virtual property identifies identify if the thing we're running
  is any kind of virtualization
- virtual() identifies what kind of virtualisation we're dealing with
- is_container() tells us if we're running in a container, or in FreeBSD's
  case, in a jail.
- the helper functions are @lru_cached, since this is very unlikely to
  change

Sponsored by: The FreeBSD Foundation
Co-authored-by: Brett Holman <brett.holman@canonical.com>

2 files changed, 80 insertions, 1 deletions

diff --git a/cloudinit/distros/freebsd.py b/cloudinit/distros/freebsd.py
index 4268abe6..706d0743 100644
--- a/cloudinit/distros/freebsd.py
+++ b/cloudinit/distros/freebsd.py
@@ -6,7 +6,9 @@
 
 import os
 import re
+from functools import lru_cache
 from io import StringIO
+from typing import Optional
 
 import cloudinit.distros.bsd
 from cloudinit import log as logging
@@ -192,5 +194,40 @@ class Distro(cloudinit.distros.bsd.BSD):
             freq=PER_INSTANCE,
         )
 
+    @lru_cache()
+    def is_container(self) -> bool:
+        """return whether we're running in a container.
+        Cached, because it's unlikely to change."""
+        jailed, _ = subp.subp(["sysctl", "-n", "security.jail.jailed"])
+        if jailed.strip() == "0":
+            return False
+        return True
+
+    @lru_cache()
+    def virtual(self) -> str:
+        """return the kind of virtualisation system we're running under.
+        Cached, because it's unlikely to change."""
+        if self.is_container():
+            return "jail"
+        # map FreeBSD's kern.vm_guest to systemd-detect-virt, just like we do
+        # in ds-identify
+        VM_GUEST_TO_SYSTEMD = {
+            "hv": "microsoft",
+            "vbox": "oracle",
+            "generic": "vm-other",
+        }
+        vm, _ = subp.subp(["sysctl", "-n", "kern.vm_guest"])
+        vm = vm.strip()
+        if vm in VM_GUEST_TO_SYSTEMD:
+            return VM_GUEST_TO_SYSTEMD[vm]
+        return vm
+
+    @property
+    def is_virtual(self) -> Optional[bool]:
+        """Detect if running on a virtual machine or bare metal.
 
-# vi: ts=4 expandtab
+        This can fail on some platforms, so the signature is Optional[bool]
+        """
+        if self.virtual() == "none":
+            return False
+        return True
diff --git a/tests/unittests/distros/test__init__.py b/tests/unittests/distros/test__init__.py
index 4201c687..ea017d58 100644
--- a/tests/unittests/distros/test__init__.py
+++ b/tests/unittests/distros/test__init__.py
@@ -275,6 +275,48 @@ class TestGenericDistro(helpers.FilesystemMockingTestCase):
                 d.is_virtual, "Reflect unknown state on ProcessExecutionError"
             )
 
+    def test_virtualization_on_freebsd(self):
+        # This test function is a bit unusual:
+        # We need to first mock away the `ifconfig -a` subp call
+        # Then, we can use side-effects to get the results of two subp calls
+        # needed for is_container()/virtual() which is_virtual depends on.
+        # We also have to clear cache between each of those assertions.
+
+        cls = distros.fetch("freebsd")
+        with mock.patch(
+            "cloudinit.distros.subp.subp", return_value=("", None)
+        ):
+            d = cls("freebsd", {}, None)
+        # This mock is called by `sysctl -n security.jail.jailed`
+        with mock.patch(
+            "cloudinit.distros.subp.subp",
+            side_effect=[("0\n", None), ("literaly any truthy value", None)],
+        ):
+            self.assertFalse(d.is_container())
+            d.is_container.cache_clear()
+            self.assertTrue(d.is_container())
+            d.is_container.cache_clear()
+
+        # This mock is called by `sysctl -n kern.vm_guest`
+        with mock.patch(
+            "cloudinit.distros.subp.subp",
+            # fmt: off
+            side_effect=[
+                ("0\n", None), ("hv\n", None),  # virtual
+                ("0\n", None), ("none\n", None),  # physical
+                ("0\n", None), ("hv\n", None)  # virtual
+            ],
+            # fmt: on
+        ):
+            self.assertEqual(d.virtual(), "microsoft")
+            d.is_container.cache_clear()
+            d.virtual.cache_clear()
+            self.assertEqual(d.virtual(), "none")
+            d.is_container.cache_clear()
+            d.virtual.cache_clear()
+
+            self.assertTrue(d.is_virtual)
+
 
 class TestGetPackageMirrors:
     def return_first(self, mlist):