powersync-plugins/usbrelay/rawhiddevicewatcher.cpp

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 *                                                                         *
 *  Copyright (C) 2019 Simon Stürz <simon.stuerz@nymea.io>                 *
 *                                                                         *
 *  This file is part of nymea.                                            *
 *                                                                         *
 *  This library is free software; you can redistribute it and/or          *
 *  modify it under the terms of the GNU Lesser General Public             *
 *  License as published by the Free Software Foundation; either           *
 *  version 2.1 of the License, or (at your option) any later version.     *
 *                                                                         *
 *  This library is distributed in the hope that it will be useful,        *
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of         *
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU      *
 *  Lesser General Public License for more details.                        *
 *                                                                         *
 *  You should have received a copy of the GNU Lesser General Public       *
 *  License along with this library; If not, see                           *
 *  <http://www.gnu.org/licenses/>.                                        *
 *                                                                         *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#include "rawhiddevicewatcher.h"
#include "extern-plugininfo.h"

RawHidDeviceWatcher::RawHidDeviceWatcher(QObject *parent) : QObject(parent)
{
    m_udev = udev_new();
    if (!m_udev) {
        qCWarning(dcUsbRelay()) << "Could not initialize udev";
        return;
    }

    // Create udev monitor
    m_monitor = udev_monitor_new_from_netlink(m_udev, "udev");
    if (!m_monitor) {
        qCWarning(dcUsbRelay()) << "Could not initialize udev monitor.";
        udev_unref(m_udev);
        m_udev = nullptr;
        return;
    }

    // Set monitor filter to USB subsystem
    if (udev_monitor_filter_add_match_subsystem_devtype(m_monitor, "hidraw", nullptr) < 0) {
        qCWarning(dcUsbRelay()) << "Could not set seubsystem device type filter to usb_device.";
        udev_monitor_unref(m_monitor);
        m_monitor = nullptr;
        udev_unref(m_udev);
        m_udev = nullptr;
        return;
    }

    // Enable the monitor
    if (udev_monitor_enable_receiving(m_monitor) < 0) {
        qCWarning(dcUsbRelay()) << "Could not enable udev monitor.";
        udev_monitor_unref(m_monitor);
        m_monitor = nullptr;
        udev_unref(m_udev);
        m_udev = nullptr;
        return;
    }

    // Read initially all devices
    struct udev_enumerate *enumerate;
    struct udev_list_entry *devices, *dev_list_entry;
    enumerate = udev_enumerate_new(m_udev);
    if (!enumerate) {
        qCWarning(dcUsbRelay()) << "Could not create udev enumerate for initial device reading.";
        udev_monitor_unref(m_monitor);
        m_monitor = nullptr;
        udev_unref(m_udev);
        m_udev = nullptr;
        return;
    }


    udev_enumerate_add_match_subsystem(enumerate, "hidraw");
    udev_enumerate_scan_devices(enumerate);

    devices = udev_enumerate_get_list_entry(enumerate);
    if (!devices) {
        qCWarning(dcUsbRelay()) << "Failed to get hidraw devices from udev enumerate.";
        udev_monitor_unref(m_monitor);
        m_monitor = nullptr;
        udev_unref(m_udev);
        m_udev = nullptr;
        return;
    }

    udev_list_entry_foreach(dev_list_entry, devices) {
        struct udev_device *device;
        const char *path;
        path = udev_list_entry_get_name(dev_list_entry);
        device = udev_device_new_from_syspath(m_udev, path);

        QString devicePath = QString::fromLatin1(udev_device_get_property_value(device,"DEVNAME"));
        udev_device_unref(device);

        qCDebug(dcUsbRelay()) << "[+]" << devicePath;
        m_devicePaths.append(devicePath);
        emit deviceAdded(devicePath);
    }

    udev_enumerate_unref(enumerate);

    // Create socket notifier for read
    m_notifier = new QSocketNotifier(udev_monitor_get_fd(m_monitor), QSocketNotifier::Read, this );
    connect(m_notifier, &QSocketNotifier::activated, this, [this](int socket){

        Q_UNUSED(socket)

        // Create udev device
        udev_device *device = udev_monitor_receive_device(m_monitor);
        if (!device) {
            qCWarning(dcUsbRelay()) << "Got socket sotification but could not read device information.";
            return;
        }

        QString actionString = QString::fromLatin1(udev_device_get_action(device));
        QString devicePath = QString::fromLatin1(udev_device_get_property_value(device,"DEVNAME"));

        // Clean udev device
        udev_device_unref(device);

        if (actionString.isEmpty())
            return;

        if (actionString == "add") {
            qCDebug(dcUsbRelay()) << "[+]" << devicePath;
            if (!m_devicePaths.contains(devicePath)) {
                m_devicePaths.append(devicePath);
                emit deviceAdded(devicePath);
            }
        }

        if (actionString == "remove") {
            qCDebug(dcUsbRelay()) << "[-]" << devicePath;
            if (m_devicePaths.contains(devicePath)) {
                m_devicePaths.removeAll(devicePath);
                emit deviceRemoved(devicePath);
            }
        }

    });

    m_notifier->setEnabled(true);
    qCDebug(dcUsbRelay()) << "Usb device watcher initialized successfully.";
}

RawHidDeviceWatcher::~RawHidDeviceWatcher()
{
    if (m_monitor)
        udev_monitor_unref(m_monitor);

    if (m_udev)
        udev_unref(m_udev);
}

QStringList RawHidDeviceWatcher::devicePaths() const
{
    return m_devicePaths;
}