| /* |
| * Copyright (C) 2018 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.android.server; |
| |
| import android.annotation.Nullable; |
| import android.os.UEventObserver; |
| import android.util.ArrayMap; |
| import android.util.Slog; |
| |
| import java.io.File; |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.Locale; |
| import java.util.Map; |
| import java.util.regex.Pattern; |
| |
| /** |
| * A specialized UEventObserver that receives UEvents from the kernel for devices in the {@code |
| * /sys/class/extcon}. directory |
| * |
| * <p>Subclass ExtconUEventObserver, implementing {@link #onUEvent(ExtconInfo, UEvent)}, then call |
| * startObserving() with a ExtconInfo to observe. The UEvent thread will then call your onUEvent() |
| * method when a UEvent occurs that matches the path of your ExtconInfos. |
| * |
| * <p>Call stopObserving() to stop receiving UEvents. |
| * |
| * <p>There is only one UEvent thread per process, even if that process has multiple UEventObserver |
| * subclass instances. The UEvent thread starts when the startObserving() is called for the first |
| * time in that process. Once started the UEvent thread will not stop (although it can stop |
| * notifying UEventObserver's via stopObserving()). |
| * |
| * @hide |
| */ |
| public abstract class ExtconUEventObserver extends UEventObserver { |
| private static final String TAG = "ExtconUEventObserver"; |
| private static final boolean LOG = false; |
| private static final String SELINUX_POLICIES_NEED_TO_BE_CHANGED = |
| "This probably means the selinux policies need to be changed."; |
| |
| private final Map<String, ExtconInfo> mExtconInfos = new ArrayMap<>(); |
| |
| @Override |
| public final void onUEvent(UEvent event) { |
| String devPath = event.get("DEVPATH"); |
| ExtconInfo info = mExtconInfos.get(devPath); |
| if (info != null) { |
| onUEvent(info, event); |
| } else { |
| Slog.w(TAG, "No match found for DEVPATH of " + event + " in " + mExtconInfos); |
| } |
| } |
| |
| /** |
| * Subclasses of ExtconUEventObserver should override this method to handle UEvents. |
| * |
| * @param extconInfo that matches the {@code DEVPATH} of {@code event} |
| * @param event the event |
| */ |
| protected abstract void onUEvent(ExtconInfo extconInfo, UEvent event); |
| |
| /** Starts observing {@link ExtconInfo#getDevicePath()}. */ |
| public void startObserving(ExtconInfo extconInfo) { |
| String devicePath = extconInfo.getDevicePath(); |
| if (devicePath == null) { |
| Slog.wtf(TAG, "Unable to start observing " + extconInfo.getName() |
| + " because the device path is null. " + SELINUX_POLICIES_NEED_TO_BE_CHANGED); |
| } else { |
| mExtconInfos.put(devicePath, extconInfo); |
| if (LOG) Slog.v(TAG, "Observing " + devicePath); |
| startObserving("DEVPATH=" + devicePath); |
| } |
| } |
| |
| /** An External Connection to watch. */ |
| public static final class ExtconInfo { |
| private static final String TAG = "ExtconInfo"; |
| |
| /** Returns a new list of all external connections whose name matches {@code regex}. */ |
| public static List<ExtconInfo> getExtconInfos(@Nullable String regex) { |
| if (!extconExists()) { |
| return new ArrayList<>(0); // Always return a new list. |
| } |
| Pattern p = regex == null ? null : Pattern.compile(regex); |
| File file = new File("/sys/class/extcon"); |
| File[] files = file.listFiles(); |
| if (files == null) { |
| Slog.wtf(TAG, file + " exists " + file.exists() + " isDir " + file.isDirectory() |
| + " but listFiles returns null. " |
| + SELINUX_POLICIES_NEED_TO_BE_CHANGED); |
| return new ArrayList<>(0); // Always return a new list. |
| } else { |
| ArrayList list = new ArrayList(files.length); |
| for (File f : files) { |
| String name = f.getName(); |
| if (p == null || p.matcher(name).matches()) { |
| ExtconInfo uei = new ExtconInfo(name); |
| list.add(uei); |
| if (LOG) Slog.d(TAG, name + " matches " + regex); |
| } else { |
| if (LOG) Slog.d(TAG, name + " does not match " + regex); |
| } |
| } |
| return list; |
| } |
| } |
| |
| private final String mName; |
| |
| public ExtconInfo(String name) { |
| mName = name; |
| } |
| |
| /** The name of the external connection */ |
| public String getName() { |
| return mName; |
| } |
| |
| /** |
| * The path to the device for this external connection. |
| * |
| * <p><b>NOTE</b> getting this path involves resolving a symlink. |
| * |
| * @return the device path, or null if it not found. |
| */ |
| @Nullable |
| public String getDevicePath() { |
| try { |
| String extconPath = String.format(Locale.US, "/sys/class/extcon/%s", mName); |
| File devPath = new File(extconPath); |
| if (devPath.exists()) { |
| String canonicalPath = devPath.getCanonicalPath(); |
| int start = canonicalPath.indexOf("/devices"); |
| return canonicalPath.substring(start); |
| } |
| return null; |
| } catch (IOException e) { |
| Slog.e(TAG, "Could not get the extcon device path for " + mName, e); |
| return null; |
| } |
| } |
| |
| /** The path to the state file */ |
| public String getStatePath() { |
| return String.format(Locale.US, "/sys/class/extcon/%s/state", mName); |
| } |
| } |
| |
| /** Does the {@link /sys/class/extcon} directory exist */ |
| public static boolean extconExists() { |
| File extconDir = new File("/sys/class/extcon"); |
| return extconDir.exists() && extconDir.isDirectory(); |
| } |
| } |