/*

 * Copyright (c) 2003, 2018, 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.

 */

/*

 * Copyright 2003 Wily Technology, Inc.

 */

#include    <jni.h>

#include    <jvmti.h>

#include    "JPLISAssert.h"

#include    "Utilities.h"

#include    "JavaExceptions.h"

/**

 * This module contains utility routines for manipulating Java throwables

 * and JNIEnv throwable state from native code.

 */

static jthrowable   sFallbackInternalError  = NULL;

/*

 * Local forward declarations.

 */

/* insist on having a throwable. If we already have one, return it.

 * If not, map to fallback

 */

jthrowable

forceFallback(jthrowable potentialException);

jthrowable

forceFallback(jthrowable potentialException) {

    if ( potentialException == NULL ) {

        return sFallbackInternalError;

    }

    else {

        return potentialException;

    }

}

/**

 *  Returns true if it properly sets up a fallback exception

 */

jboolean

initializeFallbackError(JNIEnv* jnienv) {

    jplis_assert(isSafeForJNICalls(jnienv));

    sFallbackInternalError = createInternalError(jnienv, NULL);

    jplis_assert(isSafeForJNICalls(jnienv));

    return (sFallbackInternalError != NULL);

}

/*

 *  Map everything to InternalError.

 */

jthrowable

mapAllCheckedToInternalErrorMapper( JNIEnv *    jnienv,

                                    jthrowable  throwableToMap) {

    jthrowable  mappedThrowable = NULL;

    jstring     message         = NULL;

    jplis_assert(throwableToMap != NULL);

    jplis_assert(isSafeForJNICalls(jnienv));

    jplis_assert(!isUnchecked(jnienv, throwableToMap));

    message = getMessageFromThrowable(jnienv, throwableToMap);

    mappedThrowable = createInternalError(jnienv, message);

    jplis_assert(isSafeForJNICalls(jnienv));

    return mappedThrowable;

}

jboolean

checkForThrowable(  JNIEnv*     jnienv) {

    return (*jnienv)->ExceptionCheck(jnienv);

}

jboolean

isSafeForJNICalls(  JNIEnv * jnienv) {

    return !(*jnienv)->ExceptionCheck(jnienv);

}

void

logThrowable(   JNIEnv * jnienv) {

    if ( checkForThrowable(jnienv) ) {

        (*jnienv)->ExceptionDescribe(jnienv);

    }

}

/**

 *  Creates an exception or error with the fully qualified classname (ie java/lang/Error)

 *  and message passed to its constructor

 */

jthrowable

createThrowable(    JNIEnv *        jnienv,

                    const char *    className,

                    jstring         message) {

    jthrowable  exception           = NULL;

    jmethodID   constructor         = NULL;

    jclass      exceptionClass      = NULL;

    jboolean    errorOutstanding    = JNI_FALSE;

    jplis_assert(className != NULL);

    jplis_assert(isSafeForJNICalls(jnienv));

    /* create new VMError with message from exception */

    exceptionClass = (*jnienv)->FindClass(jnienv, className);

    errorOutstanding = checkForAndClearThrowable(jnienv);

    jplis_assert(!errorOutstanding);

    if (!errorOutstanding) {

        constructor = (*jnienv)->GetMethodID(   jnienv,

                                                exceptionClass,

                                                "<init>",

                                                "(Ljava/lang/String;)V");

        errorOutstanding = checkForAndClearThrowable(jnienv);

        jplis_assert(!errorOutstanding);

    }

    if (!errorOutstanding) {

        exception = (*jnienv)->NewObject(jnienv, exceptionClass, constructor, message);

        errorOutstanding = checkForAndClearThrowable(jnienv);

        jplis_assert(!errorOutstanding);

    }

    jplis_assert(isSafeForJNICalls(jnienv));

    return exception;

}

jthrowable

createInternalError(JNIEnv * jnienv, jstring message) {

    return createThrowable( jnienv,

                            "java/lang/InternalError",

                            message);

}

jthrowable

createThrowableFromJVMTIErrorCode(JNIEnv * jnienv, jvmtiError errorCode) {

    const char * throwableClassName = NULL;

    const char * message            = NULL;

    jstring messageString           = NULL;

    switch ( errorCode ) {

        case JVMTI_ERROR_NULL_POINTER:

                throwableClassName = "java/lang/NullPointerException";

                break;

        case JVMTI_ERROR_ILLEGAL_ARGUMENT:

                throwableClassName = "java/lang/IllegalArgumentException";

                break;

        case JVMTI_ERROR_OUT_OF_MEMORY:

                throwableClassName = "java/lang/OutOfMemoryError";

                break;

        case JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION:

                throwableClassName = "java/lang/ClassCircularityError";

                break;

        case JVMTI_ERROR_FAILS_VERIFICATION:

                throwableClassName = "java/lang/VerifyError";

                break;

        case JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED:

                throwableClassName = "java/lang/UnsupportedOperationException";

                message = "class redefinition failed: attempted to add a method";

                break;

        case JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED:

                throwableClassName = "java/lang/UnsupportedOperationException";

                message = "class redefinition failed: attempted to change the schema (add/remove fields)";

                break;

        case JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED:

                throwableClassName = "java/lang/UnsupportedOperationException";

                message = "class redefinition failed: attempted to change superclass or interfaces";

                break;

        case JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED:

                throwableClassName = "java/lang/UnsupportedOperationException";

                message = "class redefinition failed: attempted to delete a method";

                break;

        case JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED:

                throwableClassName = "java/lang/UnsupportedOperationException";

                message = "class redefinition failed: attempted to change the class modifiers";

                break;

        case JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED:

                throwableClassName = "java/lang/UnsupportedOperationException";

                message = "class redefinition failed: attempted to change the class NestHost or NestMembers attribute";

                break;

        case JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED:

                throwableClassName = "java/lang/UnsupportedOperationException";

                message = "class redefinition failed: attempted to change method modifiers";

                break;

        case JVMTI_ERROR_UNSUPPORTED_VERSION:

                throwableClassName = "java/lang/UnsupportedClassVersionError";

                break;

        case JVMTI_ERROR_NAMES_DONT_MATCH:

                throwableClassName = "java/lang/NoClassDefFoundError";

                message = "class names don't match";

                break;

        case JVMTI_ERROR_INVALID_CLASS_FORMAT:

                throwableClassName = "java/lang/ClassFormatError";

                break;

        case JVMTI_ERROR_UNMODIFIABLE_CLASS:

                throwableClassName = "java/lang/instrument/UnmodifiableClassException";

                break;

        case JVMTI_ERROR_INVALID_CLASS:

                throwableClassName = "java/lang/InternalError";

                message = "class redefinition failed: invalid class";

                break;

        case JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED:

                throwableClassName = "java/lang/UnsupportedOperationException";

                message = "unsupported operation";

                break;

        case JVMTI_ERROR_INTERNAL:

        default:

                throwableClassName = "java/lang/InternalError";

                break;

        }

    if ( message != NULL ) {

        jboolean errorOutstanding;

        messageString = (*jnienv)->NewStringUTF(jnienv, message);

        errorOutstanding = checkForAndClearThrowable(jnienv);

        jplis_assert_msg(!errorOutstanding, "can't create exception java string");

    }

    return createThrowable( jnienv,

                            throwableClassName,

                            messageString);

}

/**

 *  Calls toString() on the given message which is the same call made by

 *  Exception when passed a throwable to its constructor

 */

jstring

getMessageFromThrowable(    JNIEnv*     jnienv,

                            jthrowable  exception) {

    jclass      exceptionClass      = NULL;

    jmethodID   method              = NULL;

    jstring     message             = NULL;

    jboolean    errorOutstanding    = JNI_FALSE;

    jplis_assert(isSafeForJNICalls(jnienv));

    /* call getMessage on exception */

    exceptionClass = (*jnienv)->GetObjectClass(jnienv, exception);

    errorOutstanding = checkForAndClearThrowable(jnienv);

    jplis_assert(!errorOutstanding);

    if (!errorOutstanding) {

        method = (*jnienv)->GetMethodID(jnienv,

                                        exceptionClass,

                                        "toString",

                                        "()Ljava/lang/String;");

        errorOutstanding = checkForAndClearThrowable(jnienv);

        jplis_assert(!errorOutstanding);

    }

    if (!errorOutstanding) {

        message = (*jnienv)->CallObjectMethod(jnienv, exception, method);

        errorOutstanding = checkForAndClearThrowable(jnienv);

        jplis_assert(!errorOutstanding);

    }

    jplis_assert(isSafeForJNICalls(jnienv));

    return message;

}

/**

 *  Returns whether the exception given is an unchecked exception:

 *  a subclass of Error or RuntimeException

 */

jboolean

isUnchecked(    JNIEnv*     jnienv,

                jthrowable  exception) {

    jboolean result = JNI_FALSE;

    jplis_assert(isSafeForJNICalls(jnienv));

    result =    (exception == NULL) ||

                isInstanceofClassName(jnienv, exception, "java/lang/Error") ||

                isInstanceofClassName(jnienv, exception, "java/lang/RuntimeException");

    jplis_assert(isSafeForJNICalls(jnienv));

    return result;

}

/*

 *  Returns the current throwable, if any. Clears the throwable state.

 *  Clients can use this to preserve the current throwable state on the stack.

 */

jthrowable

preserveThrowable(JNIEnv * jnienv) {

    jthrowable result = (*jnienv)->ExceptionOccurred(jnienv);

    if ( result != NULL ) {

        (*jnienv)->ExceptionClear(jnienv);

    }

    return result;

}

/*

 *  Installs the supplied throwable into the JNIEnv if the throwable is not null.

 *  Clients can use this to preserve the current throwable state on the stack.

 */

void

restoreThrowable(   JNIEnv *    jnienv,

                    jthrowable  preservedException) {

    throwThrowable( jnienv,

                    preservedException);

    return;

}

void

throwThrowable(     JNIEnv *    jnienv,

                    jthrowable  exception) {

    if ( exception != NULL ) {

        jint result = (*jnienv)->Throw(jnienv, exception);

        jplis_assert_msg(result == JNI_OK, "throwThrowable failed to re-throw");

    }

    return;

}

/*

 *  Always clears the JNIEnv throwable state. Returns true if an exception was present

 *  before the clearing operation.

 */

jboolean

checkForAndClearThrowable(  JNIEnv *    jnienv) {

    jboolean result = (*jnienv)->ExceptionCheck(jnienv);

    if ( result ) {

        (*jnienv)->ExceptionClear(jnienv);

    }

    return result;

}

/* creates a java.lang.InternalError and installs it into the JNIEnv */

void

createAndThrowInternalError(JNIEnv * jnienv) {

    jthrowable internalError = createInternalError( jnienv, NULL);

    throwThrowable(jnienv, forceFallback(internalError));

}

void

createAndThrowThrowableFromJVMTIErrorCode(JNIEnv * jnienv, jvmtiError errorCode) {

    jthrowable throwable = createThrowableFromJVMTIErrorCode(jnienv, errorCode);

    throwThrowable(jnienv, forceFallback(throwable));

}

void

mapThrownThrowableIfNecessary(  JNIEnv *                jnienv,

                                CheckedExceptionMapper  mapper) {

    jthrowable  originalThrowable   = NULL;

    jthrowable  resultThrowable     = NULL;

    originalThrowable = preserveThrowable(jnienv);

    /* the throwable is now cleared, so JNI calls are safe */

    if ( originalThrowable != NULL ) {

        /* if there is an exception: we can just throw it if it is unchecked. If checked,

         * we need to map it (mapper is conditional, will vary by usage, hence the callback)

         */

        if ( isUnchecked(jnienv, originalThrowable) ) {

            resultThrowable = originalThrowable;

        }

        else {

            resultThrowable = (*mapper) (jnienv, originalThrowable);

        }

    }

    /* re-establish the correct throwable */

    if ( resultThrowable != NULL ) {

        throwThrowable(jnienv, forceFallback(resultThrowable));

    }

}