[machineid] Implement DBUS and systemd machine-ids

- refactor running the command into a helper function,
   to deal with the regular if-command-failed-then-complain pattern.
 - mark parameters as unused.
 - move distinction about kind of DBus file up into the MachineIdJob
   and remove the enum that marked it.

src/modules/machineid/MachineIdJob.cpp

@@ -104,13 +104,21 @@ MachineIdJob::exec()
     }
     if ( m_dbus )
     {
-        auto r = MachineId::createDBusMachineId( m_dbus_symlink ? MachineId::DBusGeneration::SymlinkFromSystemD
-                                                                : MachineId::DBusGeneration::New,
-                                                 root,
-                                                 target_dbus_machineid_file );
-        if ( !r )
+        if ( m_dbus_symlink && QFile::exists( root + target_systemd_machineid_file ) )
         {
-            return r;
+            auto r = MachineId::createDBusLink( root, target_dbus_machineid_file, target_systemd_machineid_file );
+            if ( !r )
+            {
+                return r;
+            }
+        }
+        else
+        {
+            auto r = MachineId::createDBusMachineId( root, target_dbus_machineid_file );
+            if ( !r )
+            {
+                return r;
+            }
         }
     }
 

src/modules/machineid/Workers.cpp

@@ -139,10 +139,9 @@ createEntropy( const EntropyGeneration kind, const QString& rootMountPoint, cons
     return createNewEntropy( poolSize, rootMountPoint, fileName );
 }
 
-Calamares::JobResult
-createSystemdMachineId( const QString& rootMountPoint, const QString& fileName )
+static Calamares::JobResult
+runCmd( const QStringList& cmd )
 {
-    auto cmd = QStringList { QStringLiteral( "systemd-machine-id-setup" ) };
     auto r = CalamaresUtils::System::instance()->targetEnvCommand( cmd );
     if ( r.getExitCode() )
     {
@@ -153,9 +152,26 @@ createSystemdMachineId( const QString& rootMountPoint, const QString& fileName )
 }
 
 Calamares::JobResult
-createDBusMachineId( DBusGeneration kind, const QString& rootMountPoint, const QString& fileName )
+createSystemdMachineId( const QString& rootMountPoint, const QString& fileName )
 {
-    return Calamares::JobResult::internalError( QObject::tr( "Internal Error" ), QObject::tr( "Not implemented" ), 0 );
+    Q_UNUSED( rootMountPoint )
+    Q_UNUSED( fileName )
+    return runCmd( QStringList { QStringLiteral( "systemd-machine-id-setup" ) } );
+}
+
+Calamares::JobResult
+createDBusMachineId( const QString& rootMountPoint, const QString& fileName )
+{
+    Q_UNUSED( rootMountPoint )
+    Q_UNUSED( fileName )
+    return runCmd( QStringList { QStringLiteral( "dbus-uuidgen" ), QStringLiteral( "--ensure" ) } );
+}
+
+Calamares::JobResult
+createDBusLink( const QString& rootMountPoint, const QString& fileName, const QString& systemdFileName )
+{
+    Q_UNUSED( rootMountPoint );
+    return runCmd( QStringList { QStringLiteral( "ln" ), QStringLiteral( "-s" ), systemdFileName, fileName } );
 }
 
 }  // namespace MachineId

src/modules/machineid/Workers.h

@@ -67,14 +67,12 @@ createEntropy( const EntropyGeneration kind, const QString& rootMountPoint, cons
  * Creating UUIDs for DBUS and SystemD.
  */
 
-/// @brief How to create the DBus machine-id (bool-like)
-enum class DBusGeneration
-{
-    New,
-    SymlinkFromSystemD
-};
+/// @brief Create a new DBus UUID file
+Calamares::JobResult createDBusMachineId( const QString& rootMountPoint, const QString& fileName );
 
-Calamares::JobResult createDBusMachineId( DBusGeneration kind, const QString& rootMountPoint, const QString& fileName );
+/// @brief Symlink DBus UUID file to the one from systemd (which must exist already)
+Calamares::JobResult
+createDBusLink( const QString& rootMountPoint, const QString& fileName, const QString& systemdFileName );
 
 Calamares::JobResult createSystemdMachineId( const QString& rootMountPoint, const QString& fileName );