[unpackfsc] Import unpackfsc module from Calamares-extensions

This does some of the same things that unpackfs does, but
with nicer progress reporting, possibly it is faster.
It does not use rsync, so it might not be a drop-in replacement
for unpackfs.

Instead of having one configuration file with multiple items,
each unpackfsc instance unpacks just one thing.

CHANGES-3.3

@@ -10,6 +10,7 @@ the history of the 3.2 series (2018-05 - 2022-08).
 # 3.3.11 (unreleased)
 
 This release contains contributions from (alphabetically by given name):
+ - Adriaan de Groot
  - Jakob Petsovits
  - Simon Quigley
 
@@ -19,6 +20,8 @@ This release contains contributions from (alphabetically by given name):
 ## Modules ##
  - *unpackfs* now supports a `condition` configuration option for
    conditional installation / unsquash. (thanks Simon)
+ - *unpackfsc* module imported from Calamares-extensions, and extended
+   with the same `condition` configuration.
  - *partition* crash fixed when swap was using the wrong end-sector
    in some GPT configurations. (thanks Jakob, #2367)
 

src/modules/unpackfsc/CMakeLists.txt

@@ -0,0 +1,15 @@
+# SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+calamares_add_plugin( unpackfsc
+    TYPE job
+    EXPORT_MACRO PLUGINDLLEXPORT_PRO
+    SOURCES
+        UnpackFSCJob.cpp
+        # The workers for differently-packed filesystems
+        Runners.cpp
+        FSArchiverRunner.cpp
+        TarballRunner.cpp
+        UnsquashRunner.cpp
+    SHARED_LIB
+)

src/modules/unpackfsc/FSArchiverRunner.cpp

@@ -0,0 +1,117 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ */
+
+#include "FSArchiverRunner.h"
+
+#include "utils/Logger.h"
+#include "utils/Runner.h"
+
+#include <QProcess>
+
+static constexpr const int chunk_size = 137;
+static const QString&
+toolName()
+{
+    static const QString name = QStringLiteral( "fsarchiver" );
+    return name;
+}
+
+void
+FSArchiverRunner::fsarchiverProgress( QString line )
+{
+    m_since++;
+    // Typical line of output is this:
+    // -[00][ 99%][REGFILEM] /boot/thing
+    //      5   9           ^21
+    if ( m_since >= chunk_size && line.length() > 21 && line[ 5 ] == '[' && line[ 9 ] == '%' )
+    {
+        m_since = 0;
+        double p = double( line.mid( 6, 3 ).toInt() ) / 100.0;
+        const QString filename = line.mid( 22 );
+        Q_EMIT progress( p, filename );
+    }
+}
+
+Calamares::JobResult
+FSArchiverRunner::checkPrerequisites( QString& fsarchiverExecutable ) const
+{
+    if ( !checkToolExists( toolName(), fsarchiverExecutable ) )
+    {
+        return Calamares::JobResult::internalError(
+            tr( "Missing tools" ),
+            tr( "The <i>%1</i> tool is not installed on the system." ).arg( toolName() ),
+            Calamares::JobResult::MissingRequirements );
+    }
+
+    if ( !checkSourceExists() )
+    {
+        return Calamares::JobResult::internalError(
+            tr( "Invalid fsarchiver configuration" ),
+            tr( "The source archive <i>%1</i> does not exist." ).arg( m_source ),
+            Calamares::JobResult::InvalidConfiguration );
+    }
+    return Calamares::JobResult::ok();
+}
+
+Calamares::JobResult
+FSArchiverRunner::checkDestination( QString& destinationPath ) const
+{
+    destinationPath = Calamares::System::instance()->targetPath( m_destination );
+    if ( destinationPath.isEmpty() )
+    {
+        return Calamares::JobResult::internalError(
+            tr( "Invalid fsarchiver configuration" ),
+            tr( "No destination could be found for <i>%1</i>." ).arg( m_destination ),
+            Calamares::JobResult::InvalidConfiguration );
+    }
+
+    return Calamares::JobResult::ok();
+}
+
+Calamares::JobResult
+FSArchiverDirRunner::run()
+{
+    QString fsarchiverExecutable;
+    if ( auto res = checkPrerequisites( fsarchiverExecutable ); !res )
+    {
+        return res;
+    }
+    QString destinationPath;
+    if ( auto res = checkDestination( destinationPath ); !res )
+    {
+        return res;
+    }
+
+    Calamares::Utils::Runner r(
+        { fsarchiverExecutable, QStringLiteral( "-v" ), QStringLiteral( "restdir" ), m_source, destinationPath } );
+    r.setLocation( Calamares::Utils::RunLocation::RunInHost ).enableOutputProcessing();
+    connect( &r, &decltype( r )::output, this, &FSArchiverDirRunner::fsarchiverProgress );
+    return r.run().explainProcess( toolName(), std::chrono::seconds( 0 ) );
+}
+
+Calamares::JobResult
+FSArchiverFSRunner::run()
+{
+    QString fsarchiverExecutable;
+    if ( auto res = checkPrerequisites( fsarchiverExecutable ); !res )
+    {
+        return res;
+    }
+    QString destinationPath;
+    if ( auto res = checkDestination( destinationPath ); !res )
+    {
+        return res;
+    }
+
+    Calamares::Utils::Runner r(
+        { fsarchiverExecutable, QStringLiteral( "-v" ), QStringLiteral( "restfs" ), m_source, destinationPath } );
+    r.setLocation( Calamares::Utils::RunLocation::RunInHost ).enableOutputProcessing();
+    connect( &r, &decltype( r )::output, this, &FSArchiverFSRunner::fsarchiverProgress );
+    return r.run().explainProcess( toolName(), std::chrono::seconds( 0 ) );
+}

src/modules/unpackfsc/FSArchiverRunner.h

@@ -0,0 +1,59 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ */
+
+#ifndef UNPACKFSC_FSARCHIVERRUNNER_H
+#define UNPACKFSC_FSARCHIVERRUNNER_H
+
+#include "Runners.h"
+
+/** @brief Base class for runners of FSArchiver
+ *
+ */
+class FSArchiverRunner : public Runner
+{
+    Q_OBJECT
+public:
+    using Runner::Runner;
+
+protected Q_SLOTS:
+    void fsarchiverProgress( QString line );
+
+protected:
+    /** @brief Checks prerequisites, sets full path of fsarchiver in @p executable
+     */
+    Calamares::JobResult checkPrerequisites( QString& executable ) const;
+    Calamares::JobResult checkDestination( QString& destinationPath ) const;
+
+    int m_since = 0;
+};
+
+/** @brief Running FSArchiver in **dir** mode
+ *
+ */
+class FSArchiverDirRunner : public FSArchiverRunner
+{
+public:
+    using FSArchiverRunner::FSArchiverRunner;
+
+    Calamares::JobResult run() override;
+};
+
+/** @brief Running FSArchiver in **dir** mode
+ *
+ */
+class FSArchiverFSRunner : public FSArchiverRunner
+{
+public:
+    using FSArchiverRunner::FSArchiverRunner;
+
+    Calamares::JobResult run() override;
+};
+
+
+#endif

src/modules/unpackfsc/Runners.cpp

@@ -0,0 +1,38 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ */
+
+#include "Runners.h"
+
+#include <utils/System.h>
+#include <utils/Logger.h>
+
+#include <QFileInfo>
+#include <QStandardPaths>
+
+Runner::Runner( const QString& source, const QString& destination )
+    : m_source( source )
+    , m_destination( destination )
+{
+}
+
+Runner::~Runner() { }
+
+bool
+Runner::checkSourceExists() const
+{
+    QFileInfo fi( m_source );
+    return fi.exists() && fi.isReadable();
+}
+
+bool
+Runner::checkToolExists( const QString& toolName, QString& fullPath )
+{
+    fullPath = QStandardPaths::findExecutable( toolName );
+    return !fullPath.isEmpty();
+}

src/modules/unpackfsc/Runners.h

@@ -0,0 +1,48 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ */
+
+#ifndef UNPACKFSC_RUNNERS_H
+#define UNPACKFSC_RUNNERS_H
+
+#include <Job.h>
+
+class Runner : public QObject
+{
+    Q_OBJECT
+
+public:
+    Runner( const QString& source, const QString& destination );
+    ~Runner() override;
+
+    virtual Calamares::JobResult run() = 0;
+
+    /** @brief Check that the (configured) source file exists.
+     *
+     * Returns @c true if it's a file and readable.
+     */
+    bool checkSourceExists() const;
+
+    /** @brief Check that a named tool (executable) exists in the search path.
+     *
+     * Returns @c true if the tool is found and sets @p fullPath
+     * to the full path of that tool; returns @c false and clears
+     * @p fullPath otherwise.
+     */
+    static bool checkToolExists( const QString& toolName, QString& fullPath );
+
+Q_SIGNALS:
+    // See Calamares Job::progress
+    void progress( qreal percent, const QString& message );
+
+protected:
+    QString m_source;
+    QString m_destination;
+};
+
+#endif

src/modules/unpackfsc/TarballRunner.cpp

@@ -0,0 +1,86 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2022 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ */
+
+#include "TarballRunner.h"
+
+#include <utils/Logger.h>
+#include <utils/Runner.h>
+#include <utils/String.h>
+
+#include <QString>
+
+static constexpr const int chunk_size = 107;
+
+Calamares::JobResult
+TarballRunner::run()
+{
+    if ( !checkSourceExists() )
+    {
+        return Calamares::JobResult::internalError(
+            tr( "Invalid tarball configuration" ),
+            tr( "The source archive <i>%1</i> does not exist." ).arg( m_source ),
+            Calamares::JobResult::InvalidConfiguration );
+    }
+
+    const QString toolName = QStringLiteral( "tar" );
+    QString tarExecutable;
+    if ( !checkToolExists( toolName, tarExecutable ) )
+    {
+        return Calamares::JobResult::internalError(
+            tr( "Missing tools" ),
+            tr( "The <i>%1</i> tool is not installed on the system." ).arg( toolName ),
+            Calamares::JobResult::MissingRequirements );
+    }
+
+    const QString destinationPath = Calamares::System::instance()->targetPath( m_destination );
+    if ( destinationPath.isEmpty() )
+    {
+        return Calamares::JobResult::internalError(
+            tr( "Invalid tarball configuration" ),
+            tr( "No destination could be found for <i>%1</i>." ).arg( m_destination ),
+            Calamares::JobResult::InvalidConfiguration );
+    }
+
+    // Get the stats (number of inodes) from the FS
+    {
+        m_total = 0;
+        Calamares::Utils::Runner r( { tarExecutable, QStringLiteral( "-tf" ), m_source } );
+        r.setLocation( Calamares::Utils::RunLocation::RunInHost ).enableOutputProcessing();
+        QObject::connect( &r, &decltype( r )::output, [ & ]( QString line ) { m_total++; } );
+        /* ignored */ r.run();
+    }
+    if ( m_total <= 0 )
+    {
+        cWarning() << "No stats could be obtained from" << tarExecutable << "-tf" << m_source;
+    }
+
+    // Now do the actual unpack
+    {
+        m_processed = 0;
+        m_since = 0;
+        Calamares::Utils::Runner r(
+            { tarExecutable, QStringLiteral( "-xpvf" ), m_source, QStringLiteral( "-C" ), destinationPath } );
+        r.setLocation( Calamares::Utils::RunLocation::RunInHost ).enableOutputProcessing();
+        connect( &r, &decltype( r )::output, this, &TarballRunner::tarballProgress );
+        return r.run().explainProcess( toolName, std::chrono::seconds( 0 ) );
+    }
+}
+
+void
+TarballRunner::tarballProgress( QString line )
+{
+    m_processed++;
+    m_since++;
+    if ( m_since > chunk_size )
+    {
+        m_since = 0;
+        double p = m_total > 0 ? ( double( m_processed ) / double( m_total ) ) : 0.5;
+        Q_EMIT progress( p, tr( "Tarball extract file %1" ).arg( line ) );
+    }
+}

src/modules/unpackfsc/TarballRunner.h

@@ -0,0 +1,35 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2022 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ */
+
+#ifndef UNPACKFSC_TARBALLRUNNER_H
+#define UNPACKFSC_TARBALLRUNNER_H
+
+#include "Runners.h"
+
+/** @brief Use (GNU) tar for extracting a filesystem
+ *
+ */
+class TarballRunner : public Runner
+{
+public:
+    using Runner::Runner;
+
+    Calamares::JobResult run() override;
+
+protected Q_SLOTS:
+    void tarballProgress( QString line );
+
+private:
+    // Progress reporting
+    int m_total = 0;
+    int m_processed = 0;
+    int m_since = 0;
+};
+
+#endif

src/modules/unpackfsc/UnpackFSCJob.cpp

@@ -0,0 +1,194 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ */
+
+#include "UnpackFSCJob.h"
+
+#include "FSArchiverRunner.h"
+#include "TarballRunner.h"
+#include "UnsquashRunner.h"
+
+#include "GlobalStorage.h"
+#include "JobQueue.h"
+#include "compat/Variant.h"
+#include "utils/Logger.h"
+#include "utils/NamedEnum.h"
+#include "utils/RAII.h"
+#include "utils/Variant.h"
+
+#include <memory>
+
+static const NamedEnumTable< UnpackFSCJob::Type >
+typeNames()
+{
+    using T = UnpackFSCJob::Type;
+    // clang-format off
+    static const NamedEnumTable< T > names
+    {
+        { "none", T::None },
+        { "fsarchiver", T::FSArchive },
+        { "fsarchive", T::FSArchive },
+        { "fsa", T::FSArchive },
+        { "fsa-dir", T::FSArchive },
+        { "fsa-block", T::FSArchiveFS },
+        { "fsa-fs", T::FSArchiveFS },
+        { "squashfs", T::Squashfs },
+        { "squash", T::Squashfs },
+        { "unsquash", T::Squashfs },
+        { "tar", T::Tarball },
+        { "tarball", T::Tarball },
+        { "tgz", T::Tarball },
+    };
+    // clang-format on
+    return names;
+}
+
+UnpackFSCJob::UnpackFSCJob( QObject* parent )
+    : Calamares::CppJob( parent )
+{
+}
+
+UnpackFSCJob::~UnpackFSCJob() {}
+
+QString
+UnpackFSCJob::prettyName() const
+{
+    return tr( "Unpack filesystems" );
+}
+
+QString
+UnpackFSCJob::prettyStatusMessage() const
+{
+    return m_progressMessage;
+}
+
+static bool
+checkCondition( const QString& condition )
+{
+    if ( condition.isEmpty() )
+    {
+        return true;
+    }
+
+    Calamares::GlobalStorage* gs = Calamares::JobQueue::instance()->globalStorage();
+
+    bool ok = false;
+    const auto v = Calamares::lookup( gs, condition, ok );
+    if ( !ok )
+    {
+        cWarning() << "Item has condition '" << condition << "' which is not set at all (assuming 'true').";
+        return true;
+    }
+
+    if ( !v.canConvert< bool >() )
+    {
+        cWarning() << "Item has condition '" << condition << "' with value" << v << "(assuming 'true').";
+        return true;
+    }
+
+    return v.toBool();
+}
+
+Calamares::JobResult
+UnpackFSCJob::exec()
+{
+    if ( !checkCondition( m_condition ) )
+    {
+        cDebug() << "Skipping item with condition '" << m_condition << "' which is set to false.";
+        return Calamares::JobResult::ok();
+    }
+
+    cScopedAssignment messageClearer( &m_progressMessage, QString() );
+    std::unique_ptr< Runner > r;
+    switch ( m_type )
+    {
+    case Type::FSArchive:
+        r = std::make_unique< FSArchiverDirRunner >( m_source, m_destination );
+        break;
+    case Type::FSArchiveFS:
+        r = std::make_unique< FSArchiverFSRunner >( m_source, m_destination );
+        break;
+    case Type::Squashfs:
+        r = std::make_unique< UnsquashRunner >( m_source, m_destination );
+        break;
+    case Type::Tarball:
+        r = std::make_unique< TarballRunner >( m_source, m_destination );
+        break;
+    case Type::None:
+    default:
+        cDebug() << "Nothing to do.";
+        return Calamares::JobResult::ok();
+    }
+
+    connect( r.get(),
+             &Runner::progress,
+             [ = ]( qreal percent, const QString& message )
+             {
+                 m_progressMessage = message;
+                 Q_EMIT progress( percent );
+             } );
+    return r->run();
+}
+
+void
+UnpackFSCJob::setConfigurationMap( const QVariantMap& map )
+{
+    m_type = Type::None;
+
+    const QString source = Calamares::getString( map, "source" );
+    const QString sourceTypeName = Calamares::getString( map, "sourcefs" );
+    if ( source.isEmpty() || sourceTypeName.isEmpty() )
+    {
+        cWarning() << "Skipping item with bad source data:" << map;
+        return;
+    }
+    bool bogus = false;
+    Type sourceType = typeNames().find( sourceTypeName, bogus );
+    if ( sourceType == Type::None )
+    {
+        cWarning() << "Skipping item with source type None";
+        return;
+    }
+    const QString destination = Calamares::getString( map, "destination" );
+    if ( destination.isEmpty() )
+    {
+        cWarning() << "Skipping item with empty destination";
+        return;
+    }
+    const auto conditionKey = QStringLiteral( "condition" );
+    if ( map.contains( conditionKey ) )
+    {
+        const auto value = map[ conditionKey ];
+        if ( Calamares::typeOf( value ) == Calamares::BoolVariantType )
+        {
+            if ( !value.toBool() )
+            {
+                cDebug() << "Skipping item with condition set to false.";
+                // Leave type set to None, which will be skipped later
+                return;
+            }
+            // Else the condition is true, and we're fine leaving the string empty because that defaults to true
+        }
+        else
+        {
+            const auto variable = value.toString();
+            if ( variable.isEmpty() )
+            {
+                cDebug() << "Skipping item with condition '" << value << "' that is empty (use 'true' instead).";
+                return;
+            }
+            m_condition = variable;
+        }
+    }
+
+    m_source = source;
+    m_destination = destination;
+    m_type = sourceType;
+}
+
+CALAMARES_PLUGIN_FACTORY_DEFINITION( UnpackFSCFactory, registerPlugin< UnpackFSCJob >(); )

src/modules/unpackfsc/UnpackFSCJob.h

@@ -0,0 +1,51 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ */
+
+#ifndef UNPACKFSC_UNPACKFSCJOB_H
+#define UNPACKFSC_UNPACKFSCJOB_H
+
+#include <CppJob.h>
+#include <DllMacro.h>
+#include <utils/PluginFactory.h>
+
+class PLUGINDLLEXPORT UnpackFSCJob : public Calamares::CppJob
+{
+    Q_OBJECT
+
+public:
+    enum class Type
+    {
+        None,  /// << Invalid
+        FSArchive,
+        FSArchiveFS,
+        Squashfs,
+        Tarball,
+    };
+
+    explicit UnpackFSCJob( QObject* parent = nullptr );
+    ~UnpackFSCJob() override;
+
+    QString prettyName() const override;
+    QString prettyStatusMessage() const override;
+
+    Calamares::JobResult exec() override;
+
+    void setConfigurationMap( const QVariantMap& configurationMap ) override;
+
+private:
+    QString m_source;
+    QString m_destination;
+    Type m_type = Type::None;
+    QString m_progressMessage;
+    QString m_condition;  ///< May be empty to express condition "true"
+};
+
+CALAMARES_PLUGIN_FACTORY_DECLARATION( UnpackFSCFactory )
+
+#endif

src/modules/unpackfsc/UnsquashRunner.cpp

@@ -0,0 +1,101 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ */
+
+#include "UnsquashRunner.h"
+
+#include <utils/Logger.h>
+#include <utils/Runner.h>
+#include <utils/String.h>
+
+#include <QString>
+
+static constexpr const int chunk_size = 107;
+
+Calamares::JobResult
+UnsquashRunner::run()
+{
+    if ( !checkSourceExists() )
+    {
+        return Calamares::JobResult::internalError(
+            tr( "Invalid unsquash configuration" ),
+            tr( "The source archive <i>%1</i> does not exist." ).arg( m_source ),
+            Calamares::JobResult::InvalidConfiguration );
+    }
+
+    const QString toolName = QStringLiteral( "unsquashfs" );
+    QString unsquashExecutable;
+    if ( !checkToolExists( toolName, unsquashExecutable ) )
+    {
+        return Calamares::JobResult::internalError(
+            tr( "Missing tools" ),
+            tr( "The <i>%1</i> tool is not installed on the system." ).arg( toolName ),
+            Calamares::JobResult::MissingRequirements );
+    }
+
+    const QString destinationPath = Calamares::System::instance()->targetPath( m_destination );
+    if ( destinationPath.isEmpty() )
+    {
+        return Calamares::JobResult::internalError(
+            tr( "Invalid unsquash configuration" ),
+            tr( "No destination could be found for <i>%1</i>." ).arg( m_destination ),
+            Calamares::JobResult::InvalidConfiguration );
+    }
+
+    // Get the stats (number of inodes) from the FS
+    {
+        m_inodes = -1;
+        Calamares::Utils::Runner r( { unsquashExecutable, QStringLiteral( "-s" ), m_source } );
+        r.setLocation( Calamares::Utils::RunLocation::RunInHost ).enableOutputProcessing();
+        QObject::connect( &r,
+                          &decltype( r )::output,
+                          [ & ]( QString line )
+                          {
+                              if ( line.startsWith( "Number of inodes " ) )
+                              {
+                                  m_inodes = line.split( ' ', SplitSkipEmptyParts ).last().toInt();
+                              }
+                          } );
+        /* ignored */ r.run();
+    }
+    if ( m_inodes <= 0 )
+    {
+        cWarning() << "No stats could be obtained from" << unsquashExecutable << "-s";
+    }
+
+    // Now do the actual unpack
+    {
+        m_processed = 0;
+        Calamares::Utils::Runner r( { unsquashExecutable,
+                                      QStringLiteral( "-i" ),  // List files
+                                      QStringLiteral( "-f" ),  // Force-overwrite
+                                      QStringLiteral( "-d" ),
+                                      destinationPath,
+                                      m_source } );
+        r.setLocation( Calamares::Utils::RunLocation::RunInHost ).enableOutputProcessing();
+        connect( &r, &decltype( r )::output, this, &UnsquashRunner::unsquashProgress );
+        return r.run().explainProcess( toolName, std::chrono::seconds( 0 ) );
+    }
+}
+
+void
+UnsquashRunner::unsquashProgress( QString line )
+{
+    m_processed++;
+    m_since++;
+    if ( m_since > chunk_size && line.contains( '/' ) )
+    {
+        const QString filename = line.split( '/', SplitSkipEmptyParts ).last().trimmed();
+        if ( !filename.isEmpty() )
+        {
+            m_since = 0;
+            double p = m_inodes > 0 ? ( double( m_processed ) / double( m_inodes ) ) : 0.5;
+            Q_EMIT progress( p, tr( "Unsquash file %1" ).arg( filename ) );
+        }
+    }
+}

src/modules/unpackfsc/UnsquashRunner.h

@@ -0,0 +1,36 @@
+/* === This file is part of Calamares - <https://calamares.io> ===
+ *
+ *   SPDX-FileCopyrightText: 2021 Adriaan de Groot <groot@kde.org>
+ *   SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   Calamares is Free Software: see the License-Identifier above.
+ *
+ */
+
+#ifndef UNPACKFSC_UNSQUASHRUNNER_H
+#define UNPACKFSC_UNSQUASHRUNNER_H
+
+#include "Runners.h"
+
+/** @brief Use Unsquash for extracting a filesystem
+ *
+ */
+class UnsquashRunner : public Runner
+{
+public:
+    using Runner::Runner;
+
+    Calamares::JobResult run() override;
+
+protected Q_SLOTS:
+    void unsquashProgress( QString line );
+
+private:
+    int m_inodes = 0;  // Total in the FS
+
+    // Progress reporting
+    int m_processed = 0;
+    int m_since = 0;
+};
+
+#endif

src/modules/unpackfsc/tests/1.global

@@ -0,0 +1,2 @@
+---
+rootMountPoint: /tmp/fstest

src/modules/unpackfsc/tests/1.job

@@ -0,0 +1,4 @@
+---
+source: /tmp/src.fsa
+sourcefs: fsarchive
+destination: "/calasrc"

src/modules/unpackfsc/unpackfsc.conf

@@ -0,0 +1,50 @@
+# SPDX-FileCopyrightText: no
+# SPDX-License-Identifier: CC0-1.0
+#
+# Unpack a filesystem. Supported ways to "pack" the filesystem are:
+#   - fsarchiver in *savedir/restdir* mode (directories, not block devices)
+#   - squashfs
+#
+# Configuration:
+#
+#   from globalstorage: rootMountPoint
+#   from job configuration: the item to unpack
+#
+
+---
+# This module is configured a lot like the items in the *unpackfs*
+# module, but with only **one** item. Use multiple instances for
+# unpacking more than one filesystem.
+#
+# There are the following **mandatory** keys:
+#   - *source* path relative to the live / intstalling system to the image
+#   - *sourcefs* the type of the source files; valid entries are
+#       - `none` (this entry is ignored; kind of useless)
+#       - `fsarchiver`
+#         Aliases of this are `fsarchive`, `fsa` and `fsa-dir`. Uses
+#         fsarchiver in "restdir" mode.
+#       - `fsarchiver-block`
+#         Aliases of this are `fsa-block` and `fsa-fs`. Uses fsarchiver
+#         in "restfs" mode.
+#       - `squashfs`
+#         Aliases of this are `squash` and `unsquash`.
+#       - `tar`
+#   - *destination* path relative to rootMountPoint (so in the target
+#       system) where this filesystem is unpacked. It may be an
+#       empty string, which effectively is / (the root) of the target
+#       system.
+#
+#
+# There are the following **optional** keys:
+#   - *condition* sets a dynamic condition on unpacking the item in
+#     this job. This may be true or false (constant) or name a globalstorage
+#     value. Use '.' to separate parts of a globalstorage name if it is nested.
+#     Remember to quote names.
+#
+#     A condition is used in e.g. stacked squashfses, where the user can select
+#     a specific install type. The default value of *condition* is true.
+
+source: /data/rootfs.fsa
+sourcefs: fsarchiver
+destination: "/"
+# condition: true

src/modules/unpackfsc/unpackfsc.schema.yaml

@@ -0,0 +1,22 @@
+# SPDX-FileCopyrightText: 2020 Adriaan de Groot <groot@kde.org>
+# SPDX-License-Identifier: GPL-3.0-or-later
+---
+$schema: https://json-schema.org/schema#
+$id: https://calamares.io/schemas/unpackfsc
+additionalProperties: false
+type: object
+properties:
+    unpack:
+        type: array
+        items:
+            type: object
+            additionalProperties: false
+            properties:
+                source: { type: string }
+                sourcefs: { type: string }
+                destination: { type: string }
+                condition:
+                    anyOf:
+                      - type: boolean
+                      - type: string
+            required: [ source , sourcefs, destination ]