/*

 * Copyright (c) 2016, 2019, 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;

import java.util.Collections;

import java.util.List;

import java.util.Map;

import java.util.Objects;

import jdk.jfr.internal.PlatformEventType;

import jdk.jfr.internal.PlatformRecorder;

import jdk.jfr.internal.PlatformRecording;

import jdk.jfr.internal.PrivateAccess;

import jdk.jfr.internal.Type;

import jdk.jfr.internal.Utils;

/**

 * Permission for controlling access to Flight Recorder.

 * <p>

 * The following table provides a summary of what the permission

 * allows, and the risks of granting code the permission.

 *

 * <table class="striped">

 * <caption style="display:none">Table shows permission target name,

 *      what the permission allows, and associated risks</caption>

 * <thead>

 * <tr>

 * <th scope="col">Permission Target Name</th>

 * <th scope="col">What the Permission Allows</th>

 * <th scope="col">Risks of Allowing this Permission</th>

 * </tr>

 * </thead>

 *

 * <tbody>

 * <tr>

 * <th scope="row">{@code accessFlightRecorder}</th>

 * <td>Ability to create a Flight Recorder instance, register callbacks to

 * monitor the Flight Recorder life cycle, and control an existing instance

 * of Flight Recorder, which can record and dump runtime information, such as

 * stack traces, class names, and data in user defined events.</td>

 * <td>A malicious user may be able to extract sensitive information that is stored in

 * events and interrupt Flight Recorder by installing listeners or hooks that

 * never finish.</td>

 * </tr>

 * <tr>

 * <th scope="row">{@code registerEvent}</th>

 * <td>Ability to register events, write data to the Flight Recorder buffers,

 * and execute code in a callback function for periodic events.

 *

 * <td>A malicious user may be able to write sensitive information to Flight

 * Recorder buffers.</td>

 * </tr>

 * </tbody>

 * </table>

 *

 * <p>

 * Typically, programmers do not create {@code FlightRecorderPermission} objects

 * directly. Instead the objects are created by the security policy code that is based on

 * reading the security policy file.

 *

 * @since 8

 *

 * @see java.security.BasicPermission

 * @see java.security.Permission

 * @see java.security.Permissions

 * @see java.security.PermissionCollection

 * @see java.lang.SecurityManager

 *

 */

@SuppressWarnings("serial")

public final class FlightRecorderPermission extends java.security.BasicPermission {

    // Purpose of InternalAccess is to give classes in jdk.jfr.internal

    // access to package private methods in this package (jdk.jfr).

    //

    // The initialization could be done in any class in this package,

    // but this one was chosen because it is light weight and

    // lacks dependencies on other public classes.

    static {

        PrivateAccess.setPrivateAccess(new InternalAccess());

    }

    private final static class InternalAccess extends PrivateAccess {

        @Override

        public Type getType(Object o) {

            if (o instanceof AnnotationElement) {

                return ((AnnotationElement) o).getType();

            }

            if (o instanceof EventType) {

                return ((EventType) o).getType();

            }

            if (o instanceof ValueDescriptor) {

                return ((ValueDescriptor) o).getType();

            }

            if (o instanceof SettingDescriptor) {

                return ((SettingDescriptor) o).getType();

            }

            throw new Error("Unknown type " + o.getClass());

        }

        @Override

        public Configuration newConfiguration(String name, String label, String description, String provider, Map<String, String> settings, String contents) {

            return new Configuration(name, label, description, provider, settings, contents);

        }

        @Override

        public EventType newEventType(PlatformEventType platformEventType) {

            return new EventType(platformEventType);

        }

        @Override

        public AnnotationElement newAnnotation(Type annotationType, List<Object> values, boolean boot) {

            return new AnnotationElement(annotationType, values, boot);

        }

        @Override

        public ValueDescriptor newValueDescriptor(String name, Type fieldType, List<AnnotationElement> annos, int dimension, boolean constantPool, String fieldName) {

            return new ValueDescriptor(fieldType, name, annos, dimension, constantPool, fieldName);

        }

        @Override

        public PlatformRecording getPlatformRecording(Recording r) {

            return r.getInternal();

        }

        @Override

        public PlatformEventType getPlatformEventType(EventType eventType) {

            return eventType.getPlatformEventType();

        }

        @Override

        public boolean isConstantPool(ValueDescriptor v) {

            return v.isConstantPool();

        }

        @Override

        public void setAnnotations(ValueDescriptor v, List<AnnotationElement> a) {

            v.setAnnotations(a);

        }

        @Override

        public void setAnnotations(SettingDescriptor s, List<AnnotationElement> a) {

           s.setAnnotations(a);

        }

        @Override

        public String getFieldName(ValueDescriptor v) {

            return v.getJavaFieldName();

        }

        @Override

        public ValueDescriptor newValueDescriptor(Class<?> type, String name) {

            return new ValueDescriptor(type, name, Collections.emptyList(), true);

        }

        @Override

        public SettingDescriptor newSettingDescriptor(Type type, String name, String defaultValue, List<AnnotationElement> annotations) {

            return new SettingDescriptor(type, name, defaultValue, annotations);

        }

        @Override

        public boolean isUnsigned(ValueDescriptor v) {

            return v.isUnsigned();

        }

        @Override

        public PlatformRecorder getPlatformRecorder() {

            return FlightRecorder.getFlightRecorder().getInternal();

        }

    }

    /**

     * Constructs a {@code FlightRecorderPermission} with the specified name.

     *

     * @param name the permission name, must be either

     *        {@code "accessFlightRecorder"} or {@code "registerEvent"}, not

     *        {@code null}

     *

     * @throws IllegalArgumentException if {@code name} is empty or not valid

     */

    public FlightRecorderPermission(String name) {

        super(Objects.requireNonNull(name));

        if (!name.equals(Utils.ACCESS_FLIGHT_RECORDER) && !name.equals(Utils.REGISTER_EVENT)) {

            throw new IllegalArgumentException("name: " + name);

        }

    }

}