| /* |
| * Copyright (c) 2016, 2021, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package jdk.jfr.internal; |
| |
| import java.security.AccessControlContext; |
| import java.security.AccessController; |
| import java.security.PrivilegedAction; |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.Objects; |
| import java.util.Set; |
| |
| import jdk.jfr.SettingControl; |
| import jdk.jfr.internal.settings.JDKSettingControl; |
| |
| public final class Control { |
| @SuppressWarnings("removal") |
| private final AccessControlContext context; |
| private static final int CACHE_SIZE = 5; |
| private final Set<?>[] cachedUnions = new HashSet<?>[CACHE_SIZE]; |
| private final String[] cachedValues = new String[CACHE_SIZE]; |
| private final SettingControl delegate; |
| private String defaultValue; |
| private String lastValue; |
| |
| // called by exposed subclass in external API |
| public Control(SettingControl delegate, String defaultValue) { |
| this.context = PrivateAccess.getInstance().getContext(delegate); |
| this.delegate = delegate; |
| this.defaultValue = defaultValue; |
| if (this.context == null && !(delegate instanceof JDKSettingControl)) { |
| throw new InternalError("Security context can only be null for trusted setting controls"); |
| } |
| } |
| |
| boolean isType(Class<? extends SettingControl> clazz) { |
| return delegate.getClass() == clazz; |
| } |
| |
| final void apply(Set<String> values) { |
| setValue(findCombine(values)); |
| } |
| |
| final void setDefault() { |
| if (defaultValue == null) { |
| defaultValue = getValue(); |
| } |
| apply(defaultValue); |
| } |
| |
| @SuppressWarnings("removal") |
| public String getValue() { |
| if (context == null) { |
| // VM events requires no access control context |
| return getValue(); |
| } else { |
| return AccessController.doPrivileged(new PrivilegedAction<String>() { |
| @Override |
| public String run() { |
| try { |
| return delegate.getValue(); |
| } catch (Throwable t) { |
| // Prevent malicious user to propagate exception callback in the wrong context |
| Logger.log(LogTag.JFR_SETTING, LogLevel.WARN, "Exception occurred when trying to get value for " + getClass()); |
| } |
| return defaultValue != null ? defaultValue : ""; // Need to return something |
| } |
| }, context); |
| } |
| } |
| |
| private void apply(String value) { |
| if (lastValue != null && Objects.equals(value, lastValue)) { |
| return; |
| } |
| setValue(value); |
| } |
| |
| @SuppressWarnings("removal") |
| public void setValue(String value) { |
| if (context == null) { |
| // VM events requires no access control context |
| try { |
| delegate.setValue(value); |
| } catch (Throwable t) { |
| Logger.log(LogTag.JFR_SETTING, LogLevel.WARN, "Exception occurred when setting value \"" + value + "\" for " + getClass()); |
| } |
| } else { |
| AccessController.doPrivileged(new PrivilegedAction<Void>() { |
| @Override |
| public Void run() { |
| try { |
| delegate.setValue(value); |
| } catch (Throwable t) { |
| // Prevent malicious user to propagate exception callback in the wrong context |
| Logger.log(LogTag.JFR_SETTING, LogLevel.WARN, "Exception occurred when setting value \"" + value + "\" for " + getClass()); |
| } |
| return null; |
| } |
| }, context); |
| } |
| lastValue = value; |
| } |
| |
| |
| @SuppressWarnings("removal") |
| public String combine(Set<String> values) { |
| if (context == null) { |
| // VM events requires no access control context |
| return delegate.combine(values); |
| } |
| return AccessController.doPrivileged(new PrivilegedAction<String>() { |
| @Override |
| public String run() { |
| try { |
| delegate.combine(Collections.unmodifiableSet(values)); |
| } catch (Throwable t) { |
| // Prevent malicious user to propagate exception callback in the wrong context |
| Logger.log(LogTag.JFR_SETTING, LogLevel.WARN, "Exception occurred when combining " + values + " for " + getClass()); |
| } |
| return null; |
| } |
| }, context); |
| } |
| |
| private final String findCombine(Set<String> values) { |
| if (values.size() == 1) { |
| return values.iterator().next(); |
| } |
| for (int i = 0; i < CACHE_SIZE; i++) { |
| if (Objects.equals(cachedUnions[i], values)) { |
| return cachedValues[i]; |
| } |
| } |
| String result = combine(values); |
| for (int i = 0; i < CACHE_SIZE - 1; i++) { |
| cachedUnions[i + 1] = cachedUnions[i]; |
| cachedValues[i + 1] = cachedValues[i]; |
| } |
| cachedValues[0] = result; |
| cachedUnions[0] = values; |
| return result; |
| } |
| |
| final String getDefaultValue() { |
| return defaultValue; |
| } |
| |
| final String getLastValue() { |
| return lastValue; |
| } |
| } |