[partition] Add new AutoMount-manipulating helpers

src/libcalamares/CMakeLists.txt

@@ -77,6 +77,14 @@ set( libSources
     utils/Yaml.cpp
 )
 
+### OPTIONAL Automount support (requires dbus)
+#
+#
+if( Qt5DBus_FOUND)
+    list( APPEND libSources partition/AutoMount.cpp )
+    list( APPEND OPTIONAL_PRIVATE_LIBRARIES Qt5::DBus )
+endif()
+
 ### OPTIONAL Python support
 #
 #

src/libcalamares/partition/AutoMount.cpp

@@ -0,0 +1,89 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2020 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ */
+
+#include "AutoMount.h"
+
+#include "utils/Logger.h"
+
+#include <QtDBus>
+
+namespace CalamaresUtils
+{
+namespace Partition
+{
+
+struct AutoMountInfo
+{
+    bool wasSolidModuleAutoLoaded = false;
+};
+
+static inline QDBusMessage
+kdedCall( const QString& method )
+{
+    return QDBusMessage::createMethodCall(
+        QStringLiteral( "org.kde.kded5" ), QStringLiteral( "/kded" ), QStringLiteral( "org.kde.kded5" ), method );
+}
+
+// This code comes, roughly, from the KCM for removable devices.
+static void
+enableSolidAutoMount( QDBusConnection& dbus, bool enable )
+{
+    const auto moduleName = QVariant( QStringLiteral( "device_automounter" ) );
+
+    // Stop module from auto-loading
+    {
+        auto msg = kdedCall( QStringLiteral( "setModuleAutoloading" ) );
+        msg.setArguments( { moduleName, QVariant( enable ) } );
+        dbus.call( msg, QDBus::NoBlock );
+    }
+
+    // Stop module
+    {
+        auto msg = kdedCall( enable ? QStringLiteral( "loadModule" ) : QStringLiteral( "unloadModule" ) );
+        msg.setArguments( { moduleName } );
+        dbus.call( msg, QDBus::NoBlock );
+    }
+}
+
+static void
+querySolidAutoMount( QDBusConnection& dbus, AutoMountInfo& info )
+{
+    const auto moduleName = QVariant( QStringLiteral( "device_automounter" ) );
+
+    // Find previous setting; this **does** need to block
+    auto msg = kdedCall( QStringLiteral( "isModuleAutoloaded" ) );
+    msg.setArguments( { moduleName } );
+    QDBusMessage r = dbus.call( msg, QDBus::Block );
+    if ( r.type() == QDBusMessage::ReplyMessage )
+    {
+        auto arg = r.arguments();
+        cDebug() << arg;
+        info.wasSolidModuleAutoLoaded = false;
+    }
+}
+
+std::unique_ptr< AutoMountInfo >
+automountDisable()
+{
+    auto u = std::make_unique< AutoMountInfo >();
+    QDBusConnection dbus = QDBusConnection::sessionBus();
+    querySolidAutoMount( dbus, *u );
+    enableSolidAutoMount( dbus, false );
+    return u;
+}
+
+
+void
+automountRestore( std::unique_ptr< AutoMountInfo >&& t )
+{
+    QDBusConnection dbus = QDBusConnection::sessionBus();
+    enableSolidAutoMount( dbus, t->wasSolidModuleAutoLoaded );
+}
+
+}  // namespace Partition
+}  // namespace CalamaresUtils

src/libcalamares/partition/AutoMount.h

@@ -0,0 +1,48 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2020 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ *
+ */
+
+#ifndef PARTITION_AUTOMOUNT_H
+#define PARTITION_AUTOMOUNT_H
+
+#include "DllMacro.h"
+
+#include <memory>
+
+namespace CalamaresUtils
+{
+namespace Partition
+{
+
+struct AutoMountInfo;
+
+/** @brief Disable automount
+ *
+ * Various subsystems can do "agressive automount", which can get in the
+ * way of partitioning actions. In particular, Solid can be configured
+ * to automount every device it sees, and partitioning happens in multiple
+ * steps (create table, create partition, set partition flags) which are
+ * blocked if the partition gets mounted partway through the operation.
+ *
+ * Returns an opaque structure which can be passed to automountRestore()
+ * to return the system to the previously-configured automount settings.
+ */
+DLLEXPORT std::unique_ptr< AutoMountInfo > automountDisable();
+
+/** @brief Restore automount settings
+ *
+ * Pass the value returned from automountDisable() to restore the
+ * previous settings.
+ */
+DLLEXPORT void automountRestore( std::unique_ptr< AutoMountInfo >&& t );
+
+}  // namespace Partition
+}  // namespace CalamaresUtils
+
+#endif