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   1 /**
   2  * Copyright (c) 2010-2022 Contributors to the openHAB project
   3  *
   4  * See the NOTICE file(s) distributed with this work for additional
   5  * information.
   6  *
   7  * This program and the accompanying materials are made available under the
   8  * terms of the Eclipse Public License 2.0 which is available at
   9  * http://www.eclipse.org/legal/epl-2.0
  10  *
  11  * SPDX-License-Identifier: EPL-2.0
  12  */
  13 package org.openhab.binding.linuxinput.internal;
  14
  15 import static org.openhab.binding.linuxinput.internal.LinuxInputBindingConstants.THING_TYPE_DEVICE;
  16
  17 import java.io.File;
  18 import java.io.IOException;
  19 import java.nio.file.FileSystems;
  20 import java.nio.file.Path;
  21 import java.nio.file.StandardWatchEventKinds;
  22 import java.nio.file.WatchKey;
  23 import java.nio.file.WatchService;
  24 import java.time.Duration;
  25 import java.util.Collections;
  26 import java.util.concurrent.Future;
  27 import java.util.concurrent.FutureTask;
  28 import java.util.concurrent.TimeUnit;
  29
  30 import org.eclipse.jdt.annotation.NonNullByDefault;
  31 import org.eclipse.jdt.annotation.Nullable;
  32 import org.openhab.binding.linuxinput.internal.evdev4j.EvdevDevice;
  33 import org.openhab.binding.linuxinput.internal.evdev4j.LastErrorException;
  34 import org.openhab.binding.linuxinput.internal.evdev4j.jnr.EvdevLibrary;
  35 import org.openhab.core.config.discovery.AbstractDiscoveryService;
  36 import org.openhab.core.config.discovery.DiscoveryResult;
  37 import org.openhab.core.config.discovery.DiscoveryResultBuilder;
  38 import org.openhab.core.config.discovery.DiscoveryService;
  39 import org.openhab.core.thing.ThingUID;
  40 import org.osgi.service.component.annotations.Component;
  41 import org.slf4j.Logger;
  42 import org.slf4j.LoggerFactory;
  43
  44 /**
  45  * Discovery service for LinuxInputHandlers based on the /dev/input directory.
  46  *
  47  * @author Thomas Weißschuh - Initial contribution
  48  */
  49 @Component(service = DiscoveryService.class, configurationPid = "discovery.linuxinput")
  50 @NonNullByDefault
  51 public class LinuxInputDiscoveryService extends AbstractDiscoveryService {
  52
  53     private static final Duration REFRESH_INTERVAL = Duration.ofSeconds(50);
  54     private static final Duration TIMEOUT = Duration.ofSeconds(30);
  55     private static final Duration EVENT_TIMEOUT = Duration.ofSeconds(60);
  56     private static final Path DEVICE_DIRECTORY = FileSystems.getDefault().getPath("/dev/input");
  57
  58     private final Logger logger = LoggerFactory.getLogger(LinuxInputDiscoveryService.class);
  59     private @NonNullByDefault({}) Future<?> discoveryJob;
  60
  61     public LinuxInputDiscoveryService() {
  62         super(Collections.singleton(THING_TYPE_DEVICE), (int) TIMEOUT.getSeconds(), true);
  63     }
  64
  65     @Override
  66     protected void startScan() {
  67         performScan(false);
  68     }
  69
  70     private void performScan(boolean applyTtl) {
  71         logger.debug("Scanning directory {} for devices", DEVICE_DIRECTORY);
  72         removeOlderResults(getTimestampOfLastScan());
  73         File directory = DEVICE_DIRECTORY.toFile();
  74         Duration ttl = null;
  75         if (applyTtl) {
  76             ttl = REFRESH_INTERVAL.multipliedBy(2);
  77         }
  78         if (directory == null) {
  79             logger.warn("Could not open device directory {}", DEVICE_DIRECTORY);
  80             return;
  81         }
  82         File[] devices = directory.listFiles();
  83         if (devices == null) {
  84             logger.warn("Could not enumerate {}, it is not a directory", directory);
  85             return;
  86         }
  87         for (File file : devices) {
  88             handleFile(file, ttl);
  89         }
  90     }
  91
  92     private void handleFile(File file, @Nullable Duration ttl) {
  93         logger.trace("Discovering file {}", file);
  94         if (file.isDirectory()) {
  95             logger.trace("{} is not a file, ignoring", file);
  96             return;
  97         }
  98         if (!file.canRead()) {
  99             logger.debug("{} is not readable, ignoring", file);
 100             return;
 101         }
 102         DiscoveryResultBuilder result = DiscoveryResultBuilder.create(new ThingUID(THING_TYPE_DEVICE, file.getName()))
 103                 .withProperty("path", file.getAbsolutePath()).withRepresentationProperty("path");
 104         if (ttl != null) {
 105             result = result.withTTL(ttl.getSeconds());
 106         }
 107
 108         boolean shouldDiscover = enrichDevice(result, file);
 109         if (shouldDiscover) {
 110             DiscoveryResult thing = result.build();
 111             logger.debug("Discovered: {}", thing);
 112             thingDiscovered(thing);
 113         } else {
 114             logger.debug("{} is not a keyboard, ignoring", file);
 115         }
 116     }
 117
 118     private boolean enrichDevice(DiscoveryResultBuilder builder, File inputDevice) {
 119         String label = inputDevice.getName();
 120         try {
 121             try (EvdevDevice device = new EvdevDevice(inputDevice.getAbsolutePath())) {
 122                 String labelFromDevice = device.getName();
 123                 boolean isKeyboard = device.has(EvdevLibrary.Type.KEY);
 124                 if (labelFromDevice != null) {
 125                     label = String.format("%s (%s)", labelFromDevice, inputDevice.getName());
 126                 }
 127                 return isKeyboard;
 128             } finally {
 129                 builder.withLabel(label);
 130             }
 131         } catch (IOException | LastErrorException e) {
 132             logger.debug("Could not open device {}", inputDevice, e);
 133             return false;
 134         }
 135     }
 136
 137     @Override
 138     protected synchronized void stopScan() {
 139         super.stopScan();
 140         removeOlderResults(getTimestampOfLastScan());
 141     }
 142
 143     @Override
 144     protected void startBackgroundDiscovery() {
 145         logger.debug("Starting background discovery");
 146         if (discoveryJob == null || discoveryJob.isCancelled()) {
 147             WatchService watchService = null;
 148             try {
 149                 watchService = makeWatcher();
 150             } catch (IOException e) {
 151                 logger.debug("Could not start event based watcher, falling back to polling", e);
 152             }
 153             if (watchService != null) {
 154                 WatchService watcher = watchService;
 155                 FutureTask<?> job = new FutureTask<>(() -> {
 156                     waitForNewDevices(watcher);
 157                     return null;
 158                 });
 159                 Thread t = Utils.backgroundThread(job, "discovery", null);
 160                 t.start();
 161                 discoveryJob = job;
 162             } else {
 163                 discoveryJob = scheduler.scheduleWithFixedDelay(() -> performScan(true), 0,
 164                         REFRESH_INTERVAL.getSeconds(), TimeUnit.SECONDS);
 165             }
 166         }
 167     }
 168
 169     private WatchService makeWatcher() throws IOException {
 170         WatchService watchService = FileSystems.getDefault().newWatchService();
 171         // FIXME also trigger on inotify "ATTRIB" events when WatchService supports this.
 172         // Triggering on ENTRY_MODIFY will trigger multiple times on each keypress for *any* input device.
 173         DEVICE_DIRECTORY.register(watchService, StandardWatchEventKinds.ENTRY_CREATE,
 174                 StandardWatchEventKinds.ENTRY_DELETE);
 175         return watchService;
 176     }
 177
 178     private void waitForNewDevices(WatchService watchService) {
 179         while (!Thread.currentThread().isInterrupted()) {
 180             boolean gotEvent = waitAndDrainAll(watchService);
 181             logger.debug("Input devices changed: {}. Triggering rescan: {}", gotEvent, gotEvent);
 182
 183             if (gotEvent) {
 184                 performScan(false);
 185             }
 186         }
 187         logger.debug("Discovery stopped");
 188     }
 189
 190     private static boolean waitAndDrainAll(WatchService watchService) {
 191         WatchKey event;
 192         try {
 193             event = watchService.poll(EVENT_TIMEOUT.getSeconds(), TimeUnit.SECONDS);
 194         } catch (InterruptedException e) {
 195             Thread.currentThread().interrupt();
 196             return false;
 197         }
 198         if (event == null) {
 199             return false;
 200         }
 201         do {
 202             event.pollEvents();
 203             event.reset();
 204             event = watchService.poll();
 205         } while (event != null);
 206
 207         return true;
 208     }
 209
 210     @Override
 211     protected void stopBackgroundDiscovery() {
 212         logger.debug("Stopping background discovery");
 213         if (discoveryJob != null && !discoveryJob.isCancelled()) {
 214             discoveryJob.cancel(true);
 215             discoveryJob = null;
 216         }
 217     }
 218 }