[libcalamares] Add unmount helper function

src/libcalamares/partition/Mount.cpp

@@ -69,10 +69,19 @@ mount( const QString& devicePath, const QString& mountPoint, const QString& file
         args << "-o" << options;
     }
 
-    auto r = CalamaresUtils::System::instance()->runCommand( args, 10 );
+    auto r = CalamaresUtils::System::runCommand( args, 10 );
     sync();
     return r.getExitCode();
 }
 
+int
+unmount( const QString& path, const QStringList& options )
+{
+    auto r = CalamaresUtils::System::runCommand( QStringList { "umount" } << options << path, 10 );
+    sync();
+    return r.getExitCode();
+}
+
+
 }  // namespace Partition
 }  // namespace CalamaresUtils

src/libcalamares/partition/Mount.h

@@ -23,6 +23,7 @@
 #include "DllMacro.h"
 
 #include <QString>
+#include <QStringList>
 
 namespace CalamaresUtils
 {
@@ -44,6 +45,14 @@ DLLEXPORT int mount( const QString& devicePath,
                      const QString& mountPoint,
                      const QString& filesystemName = QString(),
                      const QString& options = QString() );
+
+/** @brief Unmount the given @p path (device or mount point).
+ *
+ * Runs umount(8) in the host system.
+ *
+ * @returns the program's exit codeor special codes like mount().
+ */
+DLLEXPORT int unmount( const QString& path, const QStringList& options = QStringList() );
 }  // namespace Partition
 }  // namespace CalamaresUtils