stages/systemd: ability to mask services

Add the ability to mask services, which is done e.g. when building
installers. See systemctl(1) for more information about masked
services.
Modify the existing stage test to include a test for it.

stages/org.osbuild.systemd

@@ -31,6 +31,11 @@ SCHEMA = """
     "items": { "type": "string" },
     "description": "Array of systemd unit names to be enabled"
   },
+  "masked_services": {
+    "type": "array",
+    "items": { "type": "string" },
+    "description": "Array of systemd unit names to be masked"
+  },
   "default_target": {
     "type": "string",
     "description": "The default target to boot into"
@@ -41,6 +46,7 @@ SCHEMA = """
 def main(tree, options):
     enabled_services = options["enabled_services"]
     disabled_services = options.get("disabled_services", [])
+    masked_services = options.get("masked_services", [])
     default_target = options.get("default_target")
 
     for service in enabled_services:
@@ -49,6 +55,9 @@ def main(tree, options):
     for service in disabled_services:
         subprocess.run(["systemctl", "--root", tree, "disable", service], check=True)
 
+    for service in masked_services:
+        subprocess.run(["systemctl", "--root", tree, "mask", service], check=True)
+
     if default_target:
         subprocess.run(["systemctl", "--root", tree, "set-default", default_target], check=True)
 

test/data/stages/systemd/b.json

@@ -826,6 +826,9 @@
           "enabled_services": [
             "nftables"
           ],
+          "masked_services": [
+            "ldconfig"
+          ],
           "disabled_services": [
             "sshd"
           ]

test/data/stages/systemd/diff.json

@@ -1,5 +1,6 @@
 {
   "added_files": [
+    "/etc/systemd/system/ldconfig.service",
     "/etc/systemd/system/multi-user.target.wants/nftables.service"
   ],
   "deleted_files": [