quickmod/FuseMounter/fuseinterface.cpp

#include "fuseinterface.h"
#include "fusebase.h"
#include "fusearchive.h"
#include "fuseproxy.h"
#include "fusesandbox.h"

#include <errno.h>
#include <string.h>
#include <sys/mount.h>

#define CACHE_ENABLED true
//#define FUSE_DEBUG 1

FuseInterface::FuseInterface(QSqlDatabase &database, int profileId, const QString &gameDataDir, const QString &sandboxDir, const QString &mountpoint, QObject *parent)
    : QObject{parent},
    m_fuse_id{0},
    m_fuse{nullptr},
    m_fuse_session{nullptr},
    m_notifier{nullptr},
    m_database{database},
    m_profileId{profileId},
    m_gameDataDir{gameDataDir},
    m_sandboxDir{sandboxDir},
    m_mountpoint{mountpoint}
{
    // Default to 512MB
    m_cache_data.setMaxCost(512 * 1024 * 1024);
}

FuseInterface::~FuseInterface()
{
}

bool FuseInterface::mount() {
    char mpoint[8192];

    std::string mountStr = m_mountpoint.toStdString();
    strncpy(mpoint, mountStr.c_str(), sizeof(mpoint)-1);

    // Prefer options before mountpoint so fuse_parse_cmdline finds them reliably
    char *argv[] = {
        const_cast<char *>("quickmod"),
        const_cast<char *>("-f"),
        const_cast<char *>("-o"),
        const_cast<char *>("auto_unmount"),
        mpoint,
        nullptr
    };

    int argc = sizeof(argv) / sizeof(argv[0]) - 1;
    struct fuse_args args = FUSE_ARGS_INIT(argc, (char **)argv);
    struct fuse_cmdline_opts opts;

    if( 0 != fuse_parse_cmdline(&args, &opts) ) {
        qCritical() << "Failed to parse options?";
        return false;
    }

    struct fuse_operations qmfuse_oper;
    memset( &qmfuse_oper, 0, sizeof(struct fuse_operations) );

    qmfuse_oper.getattr = f_getattr;
    qmfuse_oper.mkdir = f_mkdir;
    qmfuse_oper.unlink = f_unlink;
    qmfuse_oper.rmdir = f_rmdir;
    //qmfuse_oper.truncate = f_truncate;
    qmfuse_oper.open = f_open;
    qmfuse_oper.read = f_read;
    qmfuse_oper.write = f_write;
    qmfuse_oper.release = f_release;
    qmfuse_oper.readdir = f_readdir;
    qmfuse_oper.create = f_create;
    //qmfuse_oper.lseek = f_lseek;

    size_t op_size = sizeof(qmfuse_oper);
    m_fuse = fuse_new(&args, &qmfuse_oper, op_size, this);
    if( !m_fuse ) {
        qCritical() << "Failed to create new FUSE object.";
        return false;
    }

    if( 0 != fuse_mount(m_fuse, mpoint) ) {
        qCritical() << "Failed at fuse_mount!";
        fuse_destroy(m_fuse);
        return false;
    }

    m_fuse_session = fuse_get_session(m_fuse);
    if( 0 != fuse_set_signal_handlers(m_fuse_session) ) {
        qCritical() << "Failed to set FUSE signal handlers!";
        return false;
    }

    m_fuse_id = fuse_session_fd(m_fuse_session);
    if( m_notifier )
        m_notifier->deleteLater();

    m_notifier = new QSocketNotifier(m_fuse_id, QSocketNotifier::Read, this);
    QObject::connect( m_notifier, &QSocketNotifier::activated, this, &FuseInterface::pump );

    qDebug() << "Mounted OKAY.";
    init();

    return true;
}

int FuseInterface::pump()
{
    int ret = 0;
    do {
        struct fuse_buf fbuf;
        memset(&fbuf, 0, sizeof(struct fuse_buf));

        if( fuse_session_exited(m_fuse_session) ) {
            qDebug() << "Feh. Session closed!";
            deleteLater();
            return -1;
        }

        ret = fuse_session_receive_buf(m_fuse_session, &fbuf);
        if( -EINTR == ret )
            return 0; // Nothing to do.

        if( 0 >= ret )
            return ret;

        fuse_session_process_buf(m_fuse_session, &fbuf);
    } while(0 == ret);
    return ret;
}

void FuseInterface::unmount()
{
    if( m_notifier ) {
        m_notifier->setEnabled(false);
        m_notifier->deleteLater();
    }
    m_notifier = nullptr;

    // Stop handling signals and mark session as exiting to quiesce activity
    if( m_fuse_session ) {
        fuse_remove_signal_handlers(m_fuse_session);
        fuse_session_exit(m_fuse_session);
    }

    // Perform a lazy unmount to succeed even if handles are flushing
    // This detaches the mount and completes once all refs are closed
    if (!m_mountpoint.isEmpty()) {
        ::umount2(m_mountpoint.toStdString().c_str(), MNT_DETACH);
    }

    if( m_fuse )
    {
        fuse_unmount(m_fuse);
        fuse_destroy(m_fuse);
    }

    m_fuse = nullptr;
    m_fuse_session = nullptr;
    deleteLater();
}

void FuseInterface::init()
{
    clear();
    m_mutex.lock();

    QString sandboxDir = m_sandboxDir + QDir::separator() + QString::number(m_profileId);
    FuseAccessorSandbox *sandbox = new FuseAccessorSandbox(this, sandboxDir);
    qDebug() << "Adding sandbox dir path:" << sandboxDir;
    append(sandbox);

    QList< FuseProxyMapping > proxypaths = FuseAccessorProxy::proxyList(m_database, m_profileId);
    FuseAccessorProxy *pent = new FuseAccessorProxy(this, proxypaths);
    append(pent);

    QList< QPair<int, QString> > activeArchives = FuseAccessorArchive::activeArchives(m_database, m_profileId);
    for( const QPair<int, QString> &arc : std::as_const(activeArchives) )
    {
        qDebug() << "Adding archive:" << arc.second;
        FuseAccessorArchive *aent = new FuseAccessorArchive(this, m_database, arc.first, arc.second);
        append(aent);
    }

    FuseAccessorProxy *vanilla = new FuseAccessorProxy(this, m_gameDataDir);
    qDebug() << "Adding game data dir path:" << m_gameDataDir;
    append(vanilla);

    m_mutex.unlock();
}

void FuseInterface::clear()
{
    m_mutex.lock();
    for( FuseAccessorBase *fab : std::as_const(m_accessors) )
    {
        fab->deleteLater();
    }
    m_accessors.clear();
    m_dircache.clear();
    for( struct stat *st : std::as_const(m_cache_stat) )
        free(st);
    m_cache_stat.clear();
    m_cache_accessor.clear();
    m_cache_data.clear();
    // TODO: m_watcher?
    m_stats.clear();
    m_mutex.unlock();
}

void FuseInterface::prepend(FuseAccessorBase *accessor)
{
    m_accessors.prepend(accessor);
}

void FuseInterface::append(FuseAccessorBase *accessor)
{
    m_accessors.append(accessor);
}

void FuseInterface::remove(FuseAccessorBase *accessor)
{
    m_accessors.removeOne(accessor);
    accessor->deleteLater();
}
/*
int FuseInterface::utilQPermsToMode(QFileDevice::Permissions mode)
{
    int smode = 0;
    if( QFileDevice::ReadUser & mode ) smode += S_IRUSR;
    if( QFileDevice::WriteUser & mode ) smode += S_IWUSR;
    if( QFileDevice::ExeUser & mode ) smode += S_IXUSR;

    if( QFileDevice::ReadGroup & mode ) smode += S_IRGRP;
    if( QFileDevice::WriteGroup & mode ) smode += S_IWGRP;
    if( QFileDevice::ExeGroup & mode ) smode += S_IXGRP;

    if( QFileDevice::ReadOther & mode ) smode += S_IROTH;
    if( QFileDevice::WriteOther & mode ) smode += S_IWOTH;
    if( QFileDevice::ExeOther & mode ) smode += S_IXOTH;
    return smode;
}
*/
FuseFHBase *FuseInterface::makeWritableFromSource(const QString &source, const QString &origsource, const QString &dest, QIODeviceBase::OpenMode mode)
{
    m_mutex.lock();
    for( FuseAccessorBase *fab : std::as_const(m_accessors) )
    {
        if( FuseAccessorBase::FH_SANDBOX != fab->getType() )
            continue;

        FuseAccessorSandbox *sandbox = reinterpret_cast<FuseAccessorSandbox *>(fab);
        FuseFHBase *fh = sandbox->makeWritableFromSource(source, origsource, dest, mode);
        m_mutex.unlock();
        return fh;
    }
    m_mutex.unlock();
    return NULL;
}

FuseFHBase *FuseInterface::makeWritableFromData(const QByteArray &source, const QString &origsource, const QString &dest, QIODeviceBase::OpenMode mode)
{
    m_mutex.lock();
    for( FuseAccessorBase *fab : std::as_const(m_accessors) )
    {
        if( FuseAccessorBase::FH_SANDBOX != fab->getType() )
            continue;

        FuseAccessorSandbox *sandbox = reinterpret_cast<FuseAccessorSandbox *>(fab);
        FuseFHBase *fh = sandbox->makeWritableFromData(source, origsource, dest, mode);

        m_mutex.unlock();
        return fh;
    }
    m_mutex.unlock();
    return NULL;
}

// don't look at me, don't look at me! guhhhh~~!!!
static QString humanSize(qint64 bytes)
{
    static const char *suffixes[] = { "B", "KiB", "MiB", "GiB", "TiB" };
    double size = bytes;
    int i = 0;
    while (size >= 1024.0 && i < 4) {
        size /= 1024.0;
        ++i;
    }
    return QString::number(size, 'f', (i == 0 ? 0 : 2)) + ' ' + suffixes[i];
}

void FuseInterface::cacheInsert(const QString &path, QByteArray &data)
{
    if( data.isEmpty() )
        return;

    QSharedPointer<QByteArray> sharedData = QSharedPointer<QByteArray>::create(std::move(data));
    QSharedPointer<QByteArray> *val = new QSharedPointer<QByteArray>(std::move(sharedData));
    m_cache_data.insert(path, val, val->data()->size());
    qDebug() << " - m_cache_data now contains" << m_cache_data.size() << "entries, totalling" << humanSize(m_cache_data.totalCost()) << "bytes";

    emit entryUpdated(path, "Archive", 1, 1);
}

QSharedPointer<QByteArray> FuseInterface::cacheGrab(const QString &path)
{
    if( !m_cache_data.contains(path) )
        return {};
    auto *p = m_cache_data.object(path);
    return *p;
}

int FuseInterface::getattr(const char *path, struct stat *stbuf, struct fuse_file_info *fi)
{
    Q_UNUSED(fi)

    int ret;
    QString qpath(path);

    if( CACHE_ENABLED && m_cache_stat.contains(qpath) )
    {
        if( !m_cache_stat[qpath] )
            return -ENOENT;

        memcpy( stbuf, m_cache_stat[qpath], sizeof(struct stat) );
        return 0;
    }

    for( FuseAccessorBase *ent : std::as_const(m_accessors) )
    {
        ret = ent->getattr(qpath, stbuf);
        if( 0 == ret ) {
            struct stat *scache = (struct stat *)malloc(sizeof(struct stat));
            memcpy( scache, stbuf, sizeof(struct stat) );
            m_cache_stat.insert(qpath, scache);
            m_cache_accessor.insert(qpath, ent);
            return 0;
        }
    }

    m_cache_stat.insert(qpath, NULL);
    return -ENOENT;
}

int FuseInterface::create(const char *path, mode_t mode, struct fuse_file_info *fi)
{
    Q_UNUSED(fi)

    int ret = 1;
    QString qpath(path);
    FuseAccessorSandbox *sb = NULL;

    m_mutex.lock();
    for( FuseAccessorBase *fab : std::as_const(m_accessors) )
    {
        if( FuseAccessorBase::FH_SANDBOX != fab->getType() )
            continue;

        sb = qobject_cast<FuseAccessorSandbox *>(fab);
        QFileDevice::Permissions qmode = (QFileDevice::Permissions)mode;
        ret = sb->create(qpath, qmode);
        break;
    }

    if( CACHE_ENABLED && m_cache_stat.contains(qpath) )
    {
        struct stat *st = m_cache_stat.take(qpath);
        if( st )
            free(st);
    }

    m_mutex.unlock();
    if( 0 == ret && sb )
        return open(path, fi);

    return ret;
}

int FuseInterface::mkdir(const char *path, mode_t mode)
{
    int ret = 1;
    QString qpath(path);

    m_mutex.lock();
    for( FuseAccessorBase *fab : std::as_const(m_accessors) )
    {
        if( FuseAccessorBase::FH_SANDBOX != fab->getType() )
            continue;

        FuseAccessorSandbox *sb = qobject_cast<FuseAccessorSandbox *>(fab);
        QFileDevice::Permissions qmode = (QFileDevice::Permissions)mode;
        ret = sb->mkdir(qpath, qmode);
        break;
    }

    if( CACHE_ENABLED ) {
        if( m_cache_stat.contains(qpath) )
        {
            struct stat *st = m_cache_stat.take(qpath);
            if( st )
                free(st);
        }
        if( m_dircache.contains(qpath) )
            m_dircache.remove(qpath);
    }

    m_mutex.unlock();
    return ret;
}

int FuseInterface::unlink(const char *path)
{
    int ret = 1;
    QString qpath(path);

    m_mutex.lock();
    for( FuseAccessorBase *fab : std::as_const(m_accessors) )
    {
        if( FuseAccessorBase::FH_SANDBOX != fab->getType() )
            continue;

        FuseAccessorSandbox *sb = qobject_cast<FuseAccessorSandbox *>(fab);
        ret = sb->unlink(qpath);
        break;
    }

    if( CACHE_ENABLED ) {
        if( m_cache_stat.contains(qpath) )
        {
            struct stat *st = m_cache_stat.take(qpath);
            if( st )
                free(st);
        }
        if( m_dircache.contains(qpath) )
            m_dircache.remove(qpath);
    }

    m_mutex.unlock();
    return ret;
}

int FuseInterface::rmdir(const char *path)
{
    int ret = 1;
    QString qpath(path);

    m_mutex.lock();
    for( FuseAccessorBase *fab : std::as_const(m_accessors) )
    {
        if( FuseAccessorBase::FH_SANDBOX != fab->getType() )
            continue;

        FuseAccessorSandbox *sb = qobject_cast<FuseAccessorSandbox *>(fab);
        ret = sb->rmdir(qpath);
        break;
    }

    if( CACHE_ENABLED ) {
        if( m_cache_stat.contains(qpath) )
        {
            struct stat *st = m_cache_stat.take(qpath);
            if( st )
                free(st);
        }
        if( m_dircache.contains(qpath) )
            m_dircache.remove(qpath);
    }

    m_mutex.unlock();
    return ret;
}

int FuseInterface::rename(const char *path, const char *newname, unsigned int flags)
{
    Q_UNUSED(path)
    Q_UNUSED(newname)
    Q_UNUSED(flags)
    return 1;
}

int FuseInterface::truncate(const char *path, off_t offset, struct fuse_file_info *fi)
{
    Q_UNUSED(fi)
    int ret = 1;
    QString qpath(path);

    m_mutex.lock();
    for( FuseAccessorBase *fab : std::as_const(m_accessors) )
    {
        if( FuseAccessorBase::FH_SANDBOX != fab->getType() )
            continue;

        FuseAccessorSandbox *sb = qobject_cast<FuseAccessorSandbox *>(fab);
        ret = sb->truncate(qpath, offset);
        break;
    }

    if( CACHE_ENABLED && m_cache_stat.contains(qpath) )
    {
        struct stat *st = m_cache_stat.take(qpath);
        if( st )
            free(st);
    }

    m_mutex.unlock();
    return ret;
}

#ifndef FUSE_FILL_DIR_DEFAULTS
constexpr fuse_fill_dir_flags FUSE_FILL_DIR_DEFAULTS = static_cast<fuse_fill_dir_flags>(0);
#endif
int FuseInterface::readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi, enum fuse_readdir_flags flags)
{
    Q_UNUSED(offset)
    Q_UNUSED(fi)
    Q_UNUSED(flags)

    QString qpath(path);
    if( CACHE_ENABLED && m_dircache.contains(qpath) )
    {
        QStringList ents = m_dircache[qpath];
        for( const QString &ent : std::as_const(ents) )
            filler(buf, ent.toStdString().c_str(), NULL, 0, FUSE_FILL_DIR_DEFAULTS);
        return 0;
    }

    QStringList ents, lents;
    for( FuseAccessorBase *fab : std::as_const(m_accessors) )
    {
        QStringList dir = fab->readdir(QString(path));
        for( const QStringView nent : std::as_const(dir) )
        {
            QString blorp = nent.toString();
            QString lc = blorp.toLower();
            if( lents.contains(lc) )
                continue;

            filler(buf, blorp.toStdString().c_str(), NULL, 0, FUSE_FILL_DIR_DEFAULTS);
            ents.append(blorp);
            lents.append(lc);
        }
    }

    if( CACHE_ENABLED )
        m_dircache[qpath] = ents;

    return 0;
}

int FuseInterface::write(const char *path, const char *buf, size_t bufsz, off_t offset, struct fuse_file_info *fi)
{
    Q_UNUSED(path)
    FuseFHBase *fhbase = reinterpret_cast<FuseFHBase *>(fi->fh);
    qDebug() << "FuseFHBase:" << fhbase;

    //FuseAccessorBase *fabase = fhbase->getAccessor();
/*
    qDebug() << "fabase:" << fabase;
    qDebug() << "Type:" << fabase->getType();
*/

    FuseFHBase *sfh = qobject_cast<FuseFHBase *>(fhbase);
    QByteArray data(buf, bufsz);
    return sfh->write(data, offset, fi);
}

int FuseInterface::open(const char *path, struct fuse_file_info *fi)
{
    int fam = (fi->flags & O_ACCMODE);

    QString qpath(path);
    QIODeviceBase::OpenMode qmode;
    switch( fam )
    {
    case O_RDWR:
        qmode = QIODeviceBase::ReadWrite;
        if( !( O_TRUNC & fi->flags ) )
            qmode |= QIODeviceBase::Append;

        break;
    case O_WRONLY:
        qmode = QIODeviceBase::WriteOnly;
        if( !( O_TRUNC & fi->flags ) )
            qmode |= QIODeviceBase::Append;

        break;
    default:
        qmode = QIODeviceBase::ReadOnly;
    }

    if( !( O_CREAT & fi->flags ) )
        qmode |= QIODeviceBase::ExistingOnly;

    // STATS:
    VFSStatEntry se { qpath, QDateTime::currentSecsSinceEpoch(), 0, 0 };

    if( CACHE_ENABLED
     && QIODeviceBase::ReadOnly & qmode
     && m_cache_accessor.contains(qpath) )
    {
        FuseAccessorBase *fab = m_cache_accessor[qpath];
        FuseFHBase *fh = fab->open(qpath, qmode);
        if( fh ) {
            fi->fh = reinterpret_cast<quint64>(fh);
            m_open_handles.prepend(fh);

            if( !m_stats.contains(qpath) ) {
                qDebug() << "Adding1" << qpath;
                m_stats.insert(qpath, se);
            }
            m_stats[qpath].openCount++;
            m_stats[qpath].refCount++;
            emit entryUpdated(qpath, fab->getResource(), m_stats[qpath].openCount, m_stats[qpath].refCount);

            return 0;
        }
    }

    for( FuseAccessorBase *fab : std::as_const(m_accessors) )
    {
/*
        // FIXME: No no, we iterate through all:
        if( FuseAccessorBase::FH_SANDBOX != fab->getType()
         && QIODeviceBase::WriteOnly == qmode )
            continue;
*/
        FuseFHBase *fh = fab->open(qpath, qmode);
        if( !fh )
            continue;

        fi->fh = reinterpret_cast<quint64>(fh);
        m_open_handles.prepend(fh);

        if( !m_stats.contains(qpath) ) {
            qDebug() << "Adding2" << qpath;
            m_stats.insert(qpath, se);
        }
        m_stats[qpath].openCount++;
        m_stats[qpath].refCount++;
        emit entryUpdated(qpath, fab->getResource(), m_stats[qpath].openCount, m_stats[qpath].refCount);

        return 0;
    }

    return -EACCES;
}

int FuseInterface::release(const char *path, struct fuse_file_info *fi)
{
    Q_UNUSED(path)

    FuseFHBase *fhbase = reinterpret_cast<FuseFHBase *>(fi->fh);

    QString qpath = fhbase->getPath();
    VFSStatEntry se { qpath, QDateTime::currentSecsSinceEpoch(), 0, 0 };
    if( !m_stats.contains(qpath) )
        qDebug() << "Warning:" << qpath << "release, wasn't opened. Name was changed?";
    else {
        m_stats[qpath].refCount--;
        emit entryUpdated(qpath, fhbase->getAccessor()->getResource(), m_stats[qpath].openCount, m_stats[qpath].refCount);
    }

    m_open_handles.removeOne(fhbase);

    fhbase->release();
    fhbase->deleteLater();
    return 0;
}

int FuseInterface::read(const char *path, char *buf, size_t size, off_t offset, struct fuse_file_info *fi)
{
    Q_UNUSED(path)

    FuseFHBase *fhbase = reinterpret_cast<FuseFHBase *>(fi->fh);
    QByteArray data = fhbase->read(size, offset);
    if( data.isEmpty() )
        return 0;

    ::memcpy( buf, (void *)data.constData(), data.length() );
    return data.length();
}

off_t FuseInterface::lseek(const char *path, off_t off, int whence, struct fuse_file_info *fi)
{
    Q_UNUSED(path)

    FuseFHBase *fhbase = reinterpret_cast<FuseFHBase *>(fi->fh);
    //FuseAccessorBase *fabase = fhbase->getAccessor();
    return fhbase->lseek(off, whence);
}


// FUSE glue:
int FuseInterface::f_getattr(const char *path, struct stat *stbuf,
            struct fuse_file_info *fi)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->getattr(path, stbuf, fi);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_getattr: %s -> %d\n", path, blorg);
#endif
    return blorg;
}

int FuseInterface::f_create(const char *path, mode_t mode, struct fuse_file_info *fi)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->create(path, mode, fi);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_create: %d\n", blorg);
#endif
    return blorg;
}

int FuseInterface::f_mkdir(const char *path, mode_t mode)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->mkdir(path, mode);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_mkdir: %d\n", blorg);
#endif
    return blorg;
}

int FuseInterface::f_unlink(const char *path)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->unlink(path);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_unlink: %d\n", blorg);
#endif
    return blorg;
}

int FuseInterface::f_rmdir(const char *path)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->rmdir(path);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_rmdir: %d\n", blorg);
#endif
    return blorg;
}

int FuseInterface::f_rename(const char *path, const char *newname, unsigned int flags)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->rename(path, newname, flags);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_rename: %d\n", blorg);
#endif
    return blorg;
}

int FuseInterface::f_truncate(const char *path, off_t offset, struct fuse_file_info *fi)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->truncate(path, offset, fi);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_truncate: %d\n", blorg);
#endif
    return blorg;
}

int FuseInterface::f_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
            off_t offset, struct fuse_file_info *fi,
            enum fuse_readdir_flags flags)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->readdir(path, buf, filler, offset, fi, flags);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_readdir: %d\n", blorg);
#endif
    return blorg;
}

int FuseInterface::f_write(const char *path, const char *buf, size_t bufsz, off_t offset,
          struct fuse_file_info *fi)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->write(path, buf, bufsz, offset, fi);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_write: %d\n", blorg);
#endif
    return blorg;
}

int FuseInterface::f_open(const char *path, struct fuse_file_info *fi)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->open(path, fi);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_open: %d\n", blorg);
#endif
    return blorg;
}

int FuseInterface::f_release(const char *path, struct fuse_file_info *fi)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->release(path, fi);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_release: %d\n", blorg);
#endif
    return blorg;
}

int FuseInterface::f_read(const char *path, char *buf, size_t size, off_t offset,
         struct fuse_file_info *fi)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    int blorg = iface->read(path, buf, size, offset, fi);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_read: %d\n", blorg);
#endif
    return blorg;
}

off_t FuseInterface::f_lseek(const char *path, off_t off, int whence, struct fuse_file_info *fi)
{
    struct fuse_context *ctx = fuse_get_context();
    FuseInterface *iface = static_cast<FuseInterface*>(ctx->private_data);
    off_t blorg = iface->lseek(path, off, whence, fi);
#ifdef FUSE_DEBUG
    fprintf(stderr, "f_lseek: %ld\n", blorg);
#endif
    return blorg;
}