/*

 * Copyright (c) 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.

 *

 * 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 org.graalvm.compiler.core.test;

import static java.lang.reflect.Modifier.isProtected;

import static java.lang.reflect.Modifier.isPublic;

import java.lang.reflect.Field;

import org.graalvm.compiler.core.common.type.TypeReference;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.java.InstanceOfNode;

import org.graalvm.compiler.nodes.java.MethodCallTargetNode;

import org.graalvm.compiler.phases.VerifyPhase;

import org.graalvm.compiler.serviceprovider.GraalUnsafeAccess;

import jdk.vm.ci.meta.MetaAccessProvider;

import jdk.vm.ci.meta.ResolvedJavaMethod;

import jdk.vm.ci.meta.ResolvedJavaType;

import sun.misc.Unsafe;

/**

 * Checks that the {@link Unsafe} singleton instance is only accessed via well known classes such as

 * {@link GraalUnsafeAccess}.

 */

    @Override

        MetaAccessProvider metaAccess = context.getMetaAccess();

        final ResolvedJavaType unsafeType = metaAccess.lookupJavaType(Unsafe.class);

        ResolvedJavaMethod caller = graph.method();

        String holderQualified = caller.format("%H");

        String holderUnqualified = caller.format("%h");

        String packageName = holderQualified.equals(holderUnqualified) ? "" : holderQualified.substring(0, holderQualified.length() - holderUnqualified.length() - 1);

        if ((holderQualified.equals(GraalUnsafeAccess.class.getName()) ||

                        holderQualified.equals("jdk.vm.ci.hotspot.UnsafeAccess")) &&

                        caller.getName().equals("initUnsafe")) {

            // This is the blessed way access Unsafe in Graal and JVMCI

            return;

        } else if (packageName.startsWith("com.oracle.truffle") || packageName.startsWith("org.graalvm.compiler.truffle.runtime")) {

            // Truffle and GraalTruffleRuntime do not depend on Graal and so cannot use

            // GraalUnsafeAccess

            return;

        }

        if (caller.getSignature().getReturnType(caller.getDeclaringClass()).equals(unsafeType)) {

            if (caller.isPublic()) {

                if (holderQualified.equals(GraalUnsafeAccess.class.getName()) && caller.getName().equals("getUnsafe")) {

                    // pass

                } else {

                    throw new VerificationError("Cannot leak Unsafe from public method %s",

                                    caller.format("%H.%n(%p)"));

                }

            }

        }

        for (InstanceOfNode node : graph.getNodes().filter(InstanceOfNode.class)) {

            TypeReference typeRef = node.type();

            if (typeRef != null) {

                if (unsafeType.isAssignableFrom(typeRef.getType())) {

                    throw new VerificationError("Cast to %s in %s is prohibited as it implies accessing Unsafe.theUnsafe via reflection. Use %s.getUnsafe() instead.",

                                    unsafeType.toJavaName(),

                                    caller.format("%H.%n(%p)"),

                                    GraalUnsafeAccess.class.getName());

                }

            }

        }

        for (MethodCallTargetNode t : graph.getNodes(MethodCallTargetNode.TYPE)) {

            ResolvedJavaMethod callee = t.targetMethod();

            if (callee.getDeclaringClass().equals(unsafeType)) {

                if (callee.getName().equals("getUnsafe")) {

                    throw new VerificationError("Call to %s at callsite %s is prohibited. Use %s.getUnsafe() instead.",

                                    callee.format("%H.%n(%p)"),

                                    caller.format("%H.%n(%p)"),

                                    GraalUnsafeAccess.class.getName());

                }

            }

        }

    }

    @Override

    public void verifyClass(Class<?> c, MetaAccessProvider metaAccess) {

        for (Field field : c.getDeclaredFields()) {

            int modifiers = field.getModifiers();

            if (field.getType() == Unsafe.class && (isPublic(modifiers) || isProtected(modifiers))) {

                throw new VerificationError("Field of type %s must be private or package-private: %s", Unsafe.class.getName(), field);

            }

        }

    }

}