| /* |
| * Copyright (C) 2020 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.textclassifier.testing; |
| |
| import java.io.BufferedReader; |
| import java.io.FileReader; |
| import java.io.IOException; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * Class for reading a process' signal masks from the /proc filesystem. Looks for the |
| * BLOCKED, CAUGHT, IGNORED and PENDING masks from /proc/self/status, each of which is a |
| * 64 bit bitmask with one bit per signal. |
| * |
| * Maintains a map from SignalMaskInfo.Type to the bitmask. The {@code isValid} method |
| * will only return true if all 4 masks were successfully parsed. Provides lookup |
| * methods per signal, e.g. {@code isPending(signum)} which will throw |
| * {@code IllegalStateException} if the current data is not valid. |
| */ |
| public class SignalMaskInfo { |
| private enum Type { |
| BLOCKED("SigBlk"), |
| CAUGHT("SigCgt"), |
| IGNORED("SigIgn"), |
| PENDING("SigPnd"); |
| // The tag for this mask in /proc/self/status |
| private final String tag; |
| |
| Type(String tag) { |
| this.tag = tag + ":\t"; |
| } |
| |
| public String getTag() { |
| return tag; |
| } |
| |
| public static Map<Type, Long> parseProcinfo(String path) { |
| Map<Type, Long> map = new HashMap<>(); |
| try (BufferedReader reader = new BufferedReader(new FileReader(path))) { |
| String line; |
| while ((line = reader.readLine()) != null) { |
| for (Type mask : values()) { |
| long value = mask.tryToParse(line); |
| if (value >= 0) { |
| map.put(mask, value); |
| } |
| } |
| } |
| } catch (NumberFormatException | IOException e) { |
| // Ignored - the map will end up being invalid instead. |
| } |
| return map; |
| } |
| |
| private long tryToParse(String line) { |
| if (line.startsWith(tag)) { |
| return Long.valueOf(line.substring(tag.length()), 16); |
| } else { |
| return -1; |
| } |
| } |
| } |
| |
| private static final String PROCFS_PATH = "/proc/self/status"; |
| private Map<Type, Long> maskMap = null; |
| |
| SignalMaskInfo() { |
| refresh(); |
| } |
| |
| public void refresh() { |
| maskMap = Type.parseProcinfo(PROCFS_PATH); |
| } |
| |
| public boolean isValid() { |
| return (maskMap != null && maskMap.size() == Type.values().length); |
| } |
| |
| public boolean isCaught(int signal) { |
| return isSignalInMask(signal, Type.CAUGHT); |
| } |
| |
| public boolean isBlocked(int signal) { |
| return isSignalInMask(signal, Type.BLOCKED); |
| } |
| |
| public boolean isPending(int signal) { |
| return isSignalInMask(signal, Type.PENDING); |
| } |
| |
| public boolean isIgnored(int signal) { |
| return isSignalInMask(signal, Type.IGNORED); |
| } |
| |
| private void checkValid() { |
| if (!isValid()) { |
| throw new IllegalStateException(); |
| } |
| } |
| |
| private boolean isSignalInMask(int signal, Type mask) { |
| long bit = 1L << (signal - 1); |
| return (getSignalMask(mask) & bit) != 0; |
| } |
| |
| private long getSignalMask(Type mask) { |
| checkValid(); |
| Long value = maskMap.get(mask); |
| if (value == null) { |
| throw new IllegalStateException(); |
| } |
| return value; |
| } |
| } |