/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.tomcat.util.net.openssl.panama;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.foreign.Arena;
import java.lang.foreign.MemorySegment;
import java.lang.foreign.ValueLayout;
import java.lang.ref.Cleaner;
import java.lang.ref.Cleaner.Cleanable;
import java.nio.charset.StandardCharsets;
import java.security.KeyManagementException;
import java.security.SecureRandom;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Base64;
import java.util.Iterator;
import java.util.List;

import javax.net.ssl.KeyManager;
import javax.net.ssl.SSLEngine;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLParameters;
import javax.net.ssl.SSLServerSocketFactory;
import javax.net.ssl.SSLSessionContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509KeyManager;
import javax.net.ssl.X509TrustManager;

import static org.apache.tomcat.util.openssl.openssl_h.*;
import static org.apache.tomcat.util.openssl.openssl_h_Compatibility.*;
import static org.apache.tomcat.util.openssl.openssl_h_Macros.*;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.file.ConfigFileLoader;
import org.apache.tomcat.util.file.ConfigurationSource.Resource;
import org.apache.tomcat.util.net.Constants;
import org.apache.tomcat.util.net.SSLHostConfig;
import org.apache.tomcat.util.net.SSLHostConfig.CertificateVerification;
import org.apache.tomcat.util.net.SSLHostConfigCertificate;
import org.apache.tomcat.util.net.SSLHostConfigCertificate.Type;
import org.apache.tomcat.util.net.openssl.OpenSSLConf;
import org.apache.tomcat.util.net.openssl.OpenSSLConfCmd;
import org.apache.tomcat.util.net.openssl.OpenSSLStatus;
import org.apache.tomcat.util.net.openssl.OpenSSLUtil;
import org.apache.tomcat.util.openssl.SSL_CTX_set_alpn_select_cb$cb;
import org.apache.tomcat.util.openssl.SSL_CTX_set_cert_verify_callback$cb;
import org.apache.tomcat.util.openssl.SSL_CTX_set_tmp_dh_callback$dh;
import org.apache.tomcat.util.openssl.SSL_CTX_set_verify$callback;
import org.apache.tomcat.util.openssl.openssl_h_Compatibility;
import org.apache.tomcat.util.openssl.pem_password_cb;
import org.apache.tomcat.util.res.StringManager;

public class OpenSSLContext implements org.apache.tomcat.util.net.SSLContext {

    private static final Log log = LogFactory.getLog(OpenSSLContext.class);
    private static final StringManager sm = StringManager.getManager(OpenSSLContext.class);

    private static final Cleaner cleaner = Cleaner.create();

    private static final String defaultProtocol = "TLS";

    private static final int SSL_AIDX_RSA     = 0;
    private static final int SSL_AIDX_DSA     = 1;
    private static final int SSL_AIDX_ECC     = 3;
    private static final int SSL_AIDX_MAX     = 4;

    public static final int SSL_PROTOCOL_NONE  = 0;
    public static final int SSL_PROTOCOL_SSLV2 = (1<<0);
    public static final int SSL_PROTOCOL_SSLV3 = (1<<1);
    public static final int SSL_PROTOCOL_TLSV1 = (1<<2);
    public static final int SSL_PROTOCOL_TLSV1_1 = (1<<3);
    public static final int SSL_PROTOCOL_TLSV1_2 = (1<<4);
    public static final int SSL_PROTOCOL_TLSV1_3 = (1<<5);
    public static final int SSL_PROTOCOL_ALL = (SSL_PROTOCOL_TLSV1 | SSL_PROTOCOL_TLSV1_1 | SSL_PROTOCOL_TLSV1_2 |
            SSL_PROTOCOL_TLSV1_3);

    static final int OPTIONAL_NO_CA = 3;

    private static final String BEGIN_KEY = "-----BEGIN PRIVATE KEY-----\n";
    private static final Object END_KEY = "\n-----END PRIVATE KEY-----";

    private static final byte[] HTTP_11_PROTOCOL =
            new byte[] { 'h', 't', 't', 'p', '/', '1', '.', '1' };

    private static final byte[] DEFAULT_SESSION_ID_CONTEXT =
            new byte[] { 'd', 'e', 'f', 'a', 'u', 'l', 't' };

    static final CertificateFactory X509_CERT_FACTORY;
    static {
        try {
            X509_CERT_FACTORY = CertificateFactory.getInstance("X.509");
        } catch (CertificateException e) {
            throw new IllegalStateException(sm.getString("openssl.X509FactoryError"), e);
        }
    }

    private final SSLHostConfig sslHostConfig;
    private final SSLHostConfigCertificate certificate;
    private final boolean alpn;
    private final int minTlsVersion;
    private final int maxTlsVersion;
    private final List<byte[]> negotiableProtocols;

    private OpenSSLSessionContext sessionContext;
    private String enabledProtocol;
    private boolean initialized = false;

    private boolean noOcspCheck = false;
    private X509TrustManager x509TrustManager;

    private final ContextState state;
    private final Arena contextArena;
    private final Cleanable cleanable;

    private static String[] getCiphers(MemorySegment sslCtx) {
        MemorySegment sk = SSL_CTX_get_ciphers(sslCtx);
        int len = openssl_h_Compatibility.OPENSSL_sk_num(sk);
        if (len <= 0) {
            return null;
        }
        ArrayList<String> ciphers = new ArrayList<>(len);
        for (int i = 0; i < len; i++) {
            MemorySegment cipher = openssl_h_Compatibility.OPENSSL_sk_value(sk, i);
            MemorySegment cipherName = SSL_CIPHER_get_name(cipher);
            ciphers.add(cipherName.getString(0));
        }
        return ciphers.toArray(new String[0]);
    }

    public OpenSSLContext(SSLHostConfigCertificate certificate, List<String> negotiableProtocols)
            throws SSLException {

        // Check that OpenSSL was initialized
        if (!OpenSSLStatus.isInitialized()) {
            try {
                OpenSSLLibrary.init();
            } catch (Exception e) {
                throw new SSLException(e);
            }
        }

        this.sslHostConfig = certificate.getSSLHostConfig();
        this.certificate = certificate;
        contextArena = Arena.ofAuto();

        MemorySegment sslCtx = MemorySegment.NULL;
        MemorySegment confCtx = MemorySegment.NULL;
        List<byte[]> negotiableProtocolsBytes = null;
        boolean success = false;
        try {
            // Create OpenSSLConfCmd context if used
            OpenSSLConf openSslConf = sslHostConfig.getOpenSslConf();
            if (openSslConf != null) {
                if (log.isTraceEnabled()) {
                    log.trace(sm.getString("openssl.makeConf"));
                }
                if (!openssl_h_Compatibility.BORINGSSL) {
                    confCtx = SSL_CONF_CTX_new();
                    if (MemorySegment.NULL.equals(confCtx)) {
                        throw new SSLException(sm.getString("openssl.errMakeConf", OpenSSLLibrary.getLastError()));
                    }
                    SSL_CONF_CTX_set_flags(confCtx, SSL_CONF_FLAG_FILE() |
                            SSL_CONF_FLAG_SERVER() |
                            SSL_CONF_FLAG_CERTIFICATE() |
                            SSL_CONF_FLAG_SHOW_ERRORS());
                } else {
                    log.error(sm.getString("opensslconf.unsupported"));
                }
            }

            // SSL protocol
            sslCtx = SSL_CTX_new(TLS_server_method());

            int protocol = SSL_PROTOCOL_NONE;
            for (String enabledProtocol : sslHostConfig.getEnabledProtocols()) {
                if (Constants.SSL_PROTO_SSLv2Hello.equalsIgnoreCase(enabledProtocol)) {
                    // NO-OP. OpenSSL always supports SSLv2Hello
                } else if (Constants.SSL_PROTO_SSLv2.equalsIgnoreCase(enabledProtocol)) {
                    protocol |= SSL_PROTOCOL_SSLV2;
                } else if (Constants.SSL_PROTO_SSLv3.equalsIgnoreCase(enabledProtocol)) {
                    protocol |= SSL_PROTOCOL_SSLV3;
                } else if (Constants.SSL_PROTO_TLSv1.equalsIgnoreCase(enabledProtocol)) {
                    protocol |= SSL_PROTOCOL_TLSV1;
                } else if (Constants.SSL_PROTO_TLSv1_1.equalsIgnoreCase(enabledProtocol)) {
                    protocol |= SSL_PROTOCOL_TLSV1_1;
                } else if (Constants.SSL_PROTO_TLSv1_2.equalsIgnoreCase(enabledProtocol)) {
                    protocol |= SSL_PROTOCOL_TLSV1_2;
                } else if (Constants.SSL_PROTO_TLSv1_3.equalsIgnoreCase(enabledProtocol)) {
                    protocol |= SSL_PROTOCOL_TLSV1_3;
                } else if (Constants.SSL_PROTO_ALL.equalsIgnoreCase(enabledProtocol)) {
                    protocol |= SSL_PROTOCOL_ALL;
                } else {
                    // Should not happen since filtering to build
                    // enabled protocols removes invalid values.
                    throw new Exception(sm.getString("openssl.invalidSslProtocol", enabledProtocol));
                }
            }
            // Set maximum and minimum protocol versions
            int prot = SSL2_VERSION();
            if ((protocol & SSL_PROTOCOL_TLSV1_3) > 0) {
                prot = TLS1_3_VERSION();
            } else if ((protocol & SSL_PROTOCOL_TLSV1_2) > 0) {
                prot = TLS1_2_VERSION();
            } else if ((protocol & SSL_PROTOCOL_TLSV1_1) > 0) {
                prot = TLS1_1_VERSION();
            } else if ((protocol & SSL_PROTOCOL_TLSV1) > 0) {
                prot = TLS1_VERSION();
            } else if ((protocol & SSL_PROTOCOL_SSLV3) > 0) {
                prot = SSL3_VERSION();
            }
            maxTlsVersion = prot;
            SSL_CTX_set_max_proto_version(sslCtx, prot);
            if (prot == TLS1_3_VERSION() && (protocol & SSL_PROTOCOL_TLSV1_2) > 0) {
                prot = TLS1_2_VERSION();
            }
            if (prot == TLS1_2_VERSION() && (protocol & SSL_PROTOCOL_TLSV1_1) > 0) {
                prot = TLS1_1_VERSION();
            }
            if (prot == TLS1_1_VERSION() && (protocol & SSL_PROTOCOL_TLSV1) > 0) {
                prot = TLS1_VERSION();
            }
            if (prot == TLS1_VERSION() && (protocol & SSL_PROTOCOL_SSLV3) > 0) {
                prot = SSL3_VERSION();
            }
            minTlsVersion = prot;
            SSL_CTX_set_min_proto_version(sslCtx, prot);

            // Disable compression, usually unsafe
            openssl_h_Compatibility.SSL_CTX_set_options(sslCtx, SSL_OP_NO_COMPRESSION());

            // Disallow a session from being resumed during a renegotiation,
            // so that an acceptable cipher suite can be negotiated.
            openssl_h_Compatibility.SSL_CTX_set_options(sslCtx, SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION());

            openssl_h_Compatibility.SSL_CTX_set_options(sslCtx, SSL_OP_SINGLE_DH_USE());
            openssl_h_Compatibility.SSL_CTX_set_options(sslCtx, SSL_OP_SINGLE_ECDH_USE());

            // Default session context id and cache size
            SSL_CTX_sess_set_cache_size(sslCtx, 256);

            // Session cache is disabled by default
            SSL_CTX_set_session_cache_mode(sslCtx, SSL_SESS_CACHE_OFF());

            // Longer session timeout
            SSL_CTX_set_timeout(sslCtx, 14400);

            // Set int pem_password_cb(char *buf, int size, int rwflag, void *u) callback
            SSL_CTX_set_default_passwd_cb(sslCtx,
                    pem_password_cb.allocate(new PasswordCallback(null), contextArena));

            if (negotiableProtocols != null && negotiableProtocols.size() > 0) {
                alpn = true;
                negotiableProtocolsBytes = new ArrayList<>(negotiableProtocols.size() + 1);
                for (String negotiableProtocol : negotiableProtocols) {
                    negotiableProtocolsBytes.add(negotiableProtocol.getBytes(StandardCharsets.ISO_8859_1));
                }
                negotiableProtocolsBytes.add(HTTP_11_PROTOCOL);
            } else {
                alpn = false;
            }

            success = true;
        } catch(Exception e) {
            throw new SSLException(sm.getString("openssl.errorSSLCtxInit"), e);
        } finally {
            this.negotiableProtocols = negotiableProtocolsBytes;
            state = new ContextState(sslCtx, confCtx);
            /*
             * When an SSLHostConfig is replaced at runtime, it is not possible to
             * call destroy() on the associated OpenSSLContext since it is likely
             * that there will be in-progress connections using the OpenSSLContext.
             * A reference chain has been deliberately established (see
             * OpenSSLSessionContext) to ensure that the OpenSSLContext remains
             * ineligible for GC while those connections are alive. Once those
             * connections complete, the OpenSSLContext will become eligible for GC
             * and the memory session will ensure that the associated native
             * resources are cleaned up.
             */
            cleanable = cleaner.register(this, state);

            if (!success) {
                destroy();
            }
        }
    }


    public String getEnabledProtocol() {
        return enabledProtocol;
    }


    public void setEnabledProtocol(String protocol) {
        enabledProtocol = (protocol == null) ? defaultProtocol : protocol;
    }


    @Override
    public void destroy() {
        cleanable.clean();
    }


    private boolean checkConf(OpenSSLConf conf) throws Exception {
        boolean result = true;
        OpenSSLConfCmd cmd;
        String name;
        String value;
        int rc;
        for (OpenSSLConfCmd command : conf.getCommands()) {
            cmd = command;
            name = cmd.getName();
            value = cmd.getValue();
            if (name == null) {
                log.error(sm.getString("opensslconf.noCommandName", value));
                result = false;
                continue;
            }
            if (log.isTraceEnabled()) {
                log.trace(sm.getString("opensslconf.checkCommand", name, value));
            }
            try (var localArena = Arena.ofConfined()) {
                if (name.equals("NO_OCSP_CHECK")) {
                    rc = 1;
                } else {
                    int code = SSL_CONF_cmd_value_type(state.confCtx, localArena.allocateFrom(name));
                    rc = 1;
                    String errorMessage = OpenSSLLibrary.getLastError();
                    if (errorMessage != null) {
                        log.error(sm.getString("opensslconf.checkFailed", errorMessage));
                        rc = 0;
                    }
                    if (code == SSL_CONF_TYPE_UNKNOWN()) {
                        log.error(sm.getString("opensslconf.typeUnknown", name));
                        rc = 0;
                    }
                    if (code == SSL_CONF_TYPE_FILE()) {
                        // Check file
                        File file = new File(value);
                        if (!file.isFile() && !file.canRead()) {
                            log.error(sm.getString("opensslconf.badFile", name, value));
                            rc = 0;
                        }
                    }
                    if (code == SSL_CONF_TYPE_DIR()) {
                        // Check dir
                        File file = new File(value);
                        if (!file.isDirectory()) {
                            log.error(sm.getString("opensslconf.badDirectory", name, value));
                            rc = 0;
                        }
                    }
                }
            } catch (Exception e) {
                log.error(sm.getString("opensslconf.checkFailed", e.getLocalizedMessage()));
                return false;
            }
            if (rc <= 0) {
                log.error(sm.getString("opensslconf.failedCommand", name, value,
                        Integer.toString(rc)));
                result = false;
            } else if (log.isTraceEnabled()) {
                log.trace(sm.getString("opensslconf.resultCommand", name, value,
                        Integer.toString(rc)));
            }
        }
        if (!result) {
            log.error(sm.getString("opensslconf.checkFailed"));
        }
        return result;
    }


    private boolean applyConf(OpenSSLConf conf) throws Exception {
        boolean result = true;
        SSL_CONF_CTX_set_ssl_ctx(state.confCtx, state.sslCtx);
        OpenSSLConfCmd cmd;
        String name;
        String value;
        int rc;
        for (OpenSSLConfCmd command : conf.getCommands()) {
            cmd = command;
            name = cmd.getName();
            value = cmd.getValue();
            if (name == null) {
                log.error(sm.getString("opensslconf.noCommandName", value));
                result = false;
                continue;
            }
            if (log.isTraceEnabled()) {
                log.trace(sm.getString("opensslconf.applyCommand", name, value));
            }
            try (var localArena = Arena.ofConfined()) {
                if (name.equals("NO_OCSP_CHECK")) {
                    noOcspCheck = Boolean.parseBoolean(value);
                    rc = 1;
                } else {
                    rc = SSL_CONF_cmd(state.confCtx, localArena.allocateFrom(name),
                            localArena.allocateFrom(value));
                    String errorMessage = OpenSSLLibrary.getLastError();
                    if (rc <= 0 || errorMessage != null) {
                        log.error(sm.getString("opensslconf.commandError", name, value, errorMessage));
                        rc = 0;
                    }
                }
            } catch (Exception e) {
                log.error(sm.getString("opensslconf.applyFailed"));
                return false;
            }
            if (rc <= 0) {
                log.error(sm.getString("opensslconf.failedCommand", name, value,
                        Integer.toString(rc)));
                result = false;
            } else if (log.isTraceEnabled()) {
                log.trace(sm.getString("opensslconf.resultCommand", name, value,
                        Integer.toString(rc)));
            }
        }
        // rc = SSLConf.finish(confCtx);
        rc = SSL_CONF_CTX_finish(state.confCtx);
        if (rc <= 0) {
            log.error(sm.getString("opensslconf.finishFailed", Integer.toString(rc)));
            result = false;
        }
        if (!result) {
            log.error(sm.getString("opensslconf.applyFailed"));
        }
        return result;
    }

    /**
     * Setup the SSL_CTX.
     *
     * @param kms Must contain a KeyManager of the type
     *            {@code OpenSSLKeyManager}
     * @param tms Must contain a TrustManager of the type
     *            {@code X509TrustManager}
     * @param sr Is not used for this implementation.
     * @throws KeyManagementException if an error occurs
     */
    @Override
    public void init(KeyManager[] kms, TrustManager[] tms, SecureRandom sr) throws KeyManagementException {
        if (initialized) {
            log.warn(sm.getString("openssl.doubleInit"));
            return;
        }
        boolean success = true;
        Exception cause = null;
        try (var localArena = Arena.ofConfined()) {
            if (sslHostConfig.getInsecureRenegotiation()) {
                openssl_h_Compatibility.SSL_CTX_set_options(state.sslCtx, SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION());
            } else {
                openssl_h_Compatibility.SSL_CTX_clear_options(state.sslCtx, SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION());
            }

            // Use server's preference order for ciphers (rather than
            // client's)
            if (sslHostConfig.getHonorCipherOrder()) {
                openssl_h_Compatibility.SSL_CTX_set_options(state.sslCtx, SSL_OP_CIPHER_SERVER_PREFERENCE());
            } else {
                openssl_h_Compatibility.SSL_CTX_clear_options(state.sslCtx, SSL_OP_CIPHER_SERVER_PREFERENCE());
            }

            // Disable compression if requested
            if (sslHostConfig.getDisableCompression()) {
                openssl_h_Compatibility.SSL_CTX_set_options(state.sslCtx, SSL_OP_NO_COMPRESSION());
            } else {
                openssl_h_Compatibility.SSL_CTX_clear_options(state.sslCtx, SSL_OP_NO_COMPRESSION());
            }

            // Disable TLS Session Tickets (RFC4507) to protect perfect forward secrecy
            if (sslHostConfig.getDisableSessionTickets()) {
                openssl_h_Compatibility.SSL_CTX_set_options(state.sslCtx, SSL_OP_NO_TICKET());
            } else {
                openssl_h_Compatibility.SSL_CTX_clear_options(state.sslCtx, SSL_OP_NO_TICKET());
            }

            // List the ciphers that the client is permitted to negotiate
            if (minTlsVersion <= TLS1_2_VERSION()) {
                if (SSL_CTX_set_cipher_list(state.sslCtx,
                        localArena.allocateFrom(sslHostConfig.getCiphers())) <= 0) {
                    log.warn(sm.getString("engine.failedCipherList", sslHostConfig.getCiphers()));
                }
            }
            if (maxTlsVersion >= TLS1_3_VERSION() && (sslHostConfig.getCiphers() != SSLHostConfig.DEFAULT_TLS_CIPHERS)) {
                if (SSL_CTX_set_ciphersuites(state.sslCtx,
                        localArena.allocateFrom(sslHostConfig.getCiphers())) <= 0) {
                    log.warn(sm.getString("engine.failedCipherSuite", sslHostConfig.getCiphers()));
                }
            }

            // If there is no certificate file must be using a KeyStore so a KeyManager is required.
            // If there is a certificate file a KeyManager is helpful but not strictly necessary.
            certificate.setCertificateKeyManager(
                    OpenSSLUtil.chooseKeyManager(kms, certificate.getCertificateFile() == null));

            success = addCertificate(certificate, localArena);

            // Client certificate verification
            int value = 0;
            switch (sslHostConfig.getCertificateVerification()) {
            case NONE:
                value = SSL_VERIFY_NONE();
                break;
            case OPTIONAL:
                value = SSL_VERIFY_PEER();
                break;
            case OPTIONAL_NO_CA:
                value = OPTIONAL_NO_CA;
                break;
            case REQUIRED:
                value = SSL_VERIFY_FAIL_IF_NO_PEER_CERT();
                break;
            }

            // Set int verify_callback(int preverify_ok, X509_STORE_CTX *x509_ctx) callback
            SSL_CTX_set_verify(state.sslCtx, value,
                    SSL_CTX_set_verify$callback.allocate(new OpenSSLEngine.VerifyCallback(), contextArena));

            // Trust and certificate verification
            if (tms != null) {
                // Client certificate verification based on custom trust managers
                x509TrustManager = chooseTrustManager(tms);
                SSL_CTX_set_cert_verify_callback(state.sslCtx,
                        SSL_CTX_set_cert_verify_callback$cb.allocate(new CertVerifyCallback(x509TrustManager), contextArena), state.sslCtx);

                // Pass along the DER encoded certificates of the accepted client
                // certificate issuers, so that their subjects can be presented
                // by the server during the handshake to allow the client choosing
                // an acceptable certificate
                for (X509Certificate caCert : x509TrustManager.getAcceptedIssuers()) {
                    var rawCACertificate = localArena.allocateFrom(ValueLayout.JAVA_BYTE, caCert.getEncoded());
                    var rawCACertificatePointer = localArena.allocateFrom(ValueLayout.ADDRESS, rawCACertificate);
                    var x509CACert = d2i_X509(MemorySegment.NULL, rawCACertificatePointer, rawCACertificate.byteSize());
                    if (MemorySegment.NULL.equals(x509CACert)) {
                        logLastError("openssl.errorLoadingCertificate");
                    } else if (SSL_CTX_add_client_CA(state.sslCtx, x509CACert) <= 0) {
                        logLastError("openssl.errorAddingCertificate");
                    } else if (log.isDebugEnabled()) {
                        log.debug(sm.getString("openssl.addedClientCaCert", caCert.toString()));
                    }
                }
            } else {
                // Client certificate verification based on trusted CA files and dirs
                MemorySegment caCertificateFileNative = sslHostConfig.getCaCertificateFile() != null
                        ? localArena.allocateFrom(SSLHostConfig.adjustRelativePath(sslHostConfig.getCaCertificateFile())) : MemorySegment.NULL;
                MemorySegment caCertificatePathNative = sslHostConfig.getCaCertificatePath() != null
                        ? localArena.allocateFrom(SSLHostConfig.adjustRelativePath(sslHostConfig.getCaCertificatePath())) : MemorySegment.NULL;
                if ((sslHostConfig.getCaCertificateFile() != null || sslHostConfig.getCaCertificatePath() != null)
                        && SSL_CTX_load_verify_locations(state.sslCtx,
                                caCertificateFileNative, caCertificatePathNative) <= 0) {
                    logLastError("openssl.errorConfiguringLocations");
                } else {
                    var caCerts = SSL_CTX_get_client_CA_list(state.sslCtx);
                    if (MemorySegment.NULL.equals(caCerts)) {
                        caCerts = SSL_load_client_CA_file(caCertificateFileNative);
                        if (!MemorySegment.NULL.equals(caCerts)) {
                            SSL_CTX_set_client_CA_list(state.sslCtx, caCerts);
                        }
                    } else {
                        // OpenSSL might crash here when passing null on some platforms
                        if (MemorySegment.NULL.equals(caCertificateFileNative)
                                || (SSL_add_file_cert_subjects_to_stack(caCerts, caCertificateFileNative) <= 0)) {
                            caCerts = MemorySegment.NULL;
                        }
                    }
                    if (MemorySegment.NULL.equals(caCerts)) {
                        log.warn(sm.getString("openssl.noCACerts"));
                    }
                }
            }

            if (negotiableProtocols != null && negotiableProtocols.size() > 0) {
                SSL_CTX_set_alpn_select_cb(state.sslCtx,
                        SSL_CTX_set_alpn_select_cb$cb.allocate(new ALPNSelectCallback(negotiableProtocols), contextArena), state.sslCtx);
            }

            // Log any non fatal init errors
            String errMessage = OpenSSLLibrary.getLastError();
            while (errMessage != null) {
                log.info(sm.getString("openssl.errorInit", errMessage));
                errMessage = OpenSSLLibrary.getLastError();
            }

            // Apply OpenSSLConfCmd if used
            OpenSSLConf openSslConf = sslHostConfig.getOpenSslConf();
            if (openSslConf != null && !MemorySegment.NULL.equals(state.confCtx)) {
                // Check OpenSSLConfCmd if used
                if (log.isTraceEnabled()) {
                    log.trace(sm.getString("openssl.checkConf"));
                }
                try {
                    if (!checkConf(openSslConf)) {
                        log.error(sm.getString("openssl.errCheckConf"));
                    }
                } catch (Exception e) {
                    log.error(sm.getString("openssl.errCheckConf"), e);
                }
                if (log.isTraceEnabled()) {
                    log.trace(sm.getString("openssl.applyConf"));
                }
                try {
                    if (!applyConf(openSslConf)) {
                        log.error(sm.getString("openssl.errApplyConf"));
                    }
                } catch (Exception e) {
                    log.error(sm.getString("openssl.errApplyConf"), e);
                }
                // Reconfigure the enabled protocols
                long opts = openssl_h_Compatibility.SSL_CTX_get_options(state.sslCtx);
                List<String> enabled = new ArrayList<>();
                // Seems like there is no way to explicitly disable SSLv2Hello
                // in OpenSSL so it is always enabled
                enabled.add(Constants.SSL_PROTO_SSLv2Hello);
                if ((opts & SSL_OP_NO_TLSv1()) == 0) {
                    enabled.add(Constants.SSL_PROTO_TLSv1);
                }
                if ((opts & SSL_OP_NO_TLSv1_1()) == 0) {
                    enabled.add(Constants.SSL_PROTO_TLSv1_1);
                }
                if ((opts & SSL_OP_NO_TLSv1_2()) == 0) {
                    enabled.add(Constants.SSL_PROTO_TLSv1_2);
                }
                if ((opts & SSL_OP_NO_TLSv1_3()) == 0) {
                    enabled.add(Constants.SSL_PROTO_TLSv1_3);
                }
                if ((opts & SSL_OP_NO_SSLv2()) == 0) {
                    enabled.add(Constants.SSL_PROTO_SSLv2);
                }
                if ((opts & SSL_OP_NO_SSLv3()) == 0) {
                    enabled.add(Constants.SSL_PROTO_SSLv3);
                }
                sslHostConfig.setEnabledProtocols(
                        enabled.toArray(new String[0]));
                // Reconfigure the enabled ciphers
                sslHostConfig.setEnabledCiphers(getCiphers(state.sslCtx));
            }

            sessionContext = new OpenSSLSessionContext(this);
            // If client authentication is being used, OpenSSL requires that
            // this is set so always set it in case an app is configured to
            // require it
            sessionContext.setSessionIdContext(DEFAULT_SESSION_ID_CONTEXT);
            sslHostConfig.setOpenSslContext(Long.valueOf(state.sslCtx.address()));
            initialized = true;
        } catch (Exception e) {
            cause = e;
            success = false;
        }
        if (!success) {
            destroy();
            throw new KeyManagementException(sm.getString("openssl.errorSSLCtxInit"), cause);
        }
    }


    public MemorySegment getSSLContext() {
        return state.sslCtx;
    }

    // DH *(*tmp_dh_callback)(SSL *ssl, int is_export, int keylength)
    private static class TmpDHCallback implements SSL_CTX_set_tmp_dh_callback$dh.Function {
        @Override
        public MemorySegment apply(MemorySegment ssl, int isExport, int keylength) {
            var pkey = SSL_get_privatekey(ssl);
            int type = (MemorySegment.NULL.equals(pkey)) ? EVP_PKEY_NONE() : EVP_PKEY_base_id(pkey);
            /*
             * OpenSSL will call us with either keylen == 512 or keylen == 1024
             * (see the definition of SSL_EXPORT_PKEYLENGTH in ssl_locl.h).
             * Adjust the DH parameter length according to the size of the
             * RSA/DSA private key used for the current connection, and always
             * use at least 1024-bit parameters.
             * Note: This may cause interoperability issues with implementations
             * which limit their DH support to 1024 bit - e.g. Java 7 and earlier.
             * In this case, SSLCertificateFile can be used to specify fixed
             * 1024-bit DH parameters (with the effect that OpenSSL skips this
             * callback).
             */
            int keylen = 0;
            if (type == EVP_PKEY_RSA() || type == EVP_PKEY_DSA()) {
                keylen = EVP_PKEY_bits(pkey);
            }
            for (int i = 0; i < OpenSSLLibrary.dhParameters.length; i++) {
                if (OpenSSLLibrary.dhParameters[i] != null && keylen >= OpenSSLLibrary.dhParameters[i].min) {
                    return OpenSSLLibrary.dhParameters[i].dh;
                }
            }
            return MemorySegment.NULL;
        }
    }

    // int SSL_callback_alpn_select_proto(SSL* ssl, const unsigned char **out, unsigned char *outlen,
    //        const unsigned char *in, unsigned int inlen, void *arg)
    private static class ALPNSelectCallback implements SSL_CTX_set_alpn_select_cb$cb.Function {
        private final List<byte[]> negotiableProtocols;
        ALPNSelectCallback(List<byte[]> negotiableProtocols) {
            this.negotiableProtocols = negotiableProtocols;
        }
        @Override
        public int apply(MemorySegment ssl, MemorySegment out,
                MemorySegment outlen, MemorySegment in, int inlen, MemorySegment arg) {
            try (var localArena = Arena.ofConfined()) {
                MemorySegment inSeg = in.reinterpret(inlen, localArena, null);
                byte[] advertisedBytes = inSeg.toArray(ValueLayout.JAVA_BYTE);
                for (byte[] negotiableProtocolBytes : negotiableProtocols) {
                    for (int i = 0; i <= advertisedBytes.length - negotiableProtocolBytes.length; i++) {
                        if (advertisedBytes[i] == negotiableProtocolBytes[0]) {
                            for (int j = 0; j < negotiableProtocolBytes.length; j++) {
                                if (advertisedBytes[i + j] == negotiableProtocolBytes[j]) {
                                    if (j == negotiableProtocolBytes.length - 1) {
                                        // Match
                                        MemorySegment outSeg = out.reinterpret(ValueLayout.ADDRESS.byteSize(), localArena, null);
                                        outSeg.set(ValueLayout.ADDRESS, 0, inSeg.asSlice(i));
                                        MemorySegment outlenSeg = outlen.reinterpret(ValueLayout.JAVA_BYTE.byteSize(), localArena, null);
                                        outlenSeg.set(ValueLayout.JAVA_BYTE, 0, (byte) negotiableProtocolBytes.length);
                                        return SSL_TLSEXT_ERR_OK();
                                    }
                                } else {
                                    break;
                                }
                            }
                        }
                    }
                }
            }
            return SSL_TLSEXT_ERR_NOACK();
        }
    }


    private static class CertVerifyCallback implements SSL_CTX_set_cert_verify_callback$cb.Function {
        private final X509TrustManager x509TrustManager;
        CertVerifyCallback(X509TrustManager x509TrustManager) {
            this.x509TrustManager = x509TrustManager;
        }
        @Override
        public int apply(MemorySegment /*X509_STORE_CTX*/ x509_ctx, MemorySegment param) {
            if (log.isTraceEnabled()) {
                log.trace("Certificate verification");
            }
            if (MemorySegment.NULL.equals(param)) {
                return 0;
            }
            MemorySegment ssl = X509_STORE_CTX_get_ex_data(x509_ctx, SSL_get_ex_data_X509_STORE_CTX_idx());
            MemorySegment /*STACK_OF(X509)*/ sk = X509_STORE_CTX_get0_untrusted(x509_ctx);
            int len = openssl_h_Compatibility.OPENSSL_sk_num(sk);
            byte[][] certificateChain = new byte[len][];
            try (var localArena = Arena.ofConfined()) {
                for (int i = 0; i < len; i++) {
                    MemorySegment/*(X509*)*/ x509 = openssl_h_Compatibility.OPENSSL_sk_value(sk, i);
                    MemorySegment bufPointer = localArena.allocateFrom(ValueLayout.ADDRESS, MemorySegment.NULL);
                    int length = i2d_X509(x509, bufPointer);
                    if (length < 0) {
                        certificateChain[i] = new byte[0];
                        continue;
                    }
                    MemorySegment buf = bufPointer.get(ValueLayout.ADDRESS, 0);
                    certificateChain[i] = buf.reinterpret(length, localArena, null).toArray(ValueLayout.JAVA_BYTE);
                    OPENSSL_free(buf);
                }
                MemorySegment cipher = SSL_get_current_cipher(ssl);
                String authMethod = (MemorySegment.NULL.equals(cipher)) ? "UNKNOWN"
                        : getCipherAuthenticationMethod(SSL_CIPHER_get_auth_nid(cipher), SSL_CIPHER_get_kx_nid(cipher));
                X509Certificate[] peerCerts = certificates(certificateChain);
                try {
                    x509TrustManager.checkClientTrusted(peerCerts, authMethod);
                    return 1;
                } catch (Exception e) {
                    log.debug(sm.getString("openssl.certificateVerificationFailed"), e);
                }
            }
            return 0;
        }
    }

    private static final int NID_kx_rsa = 1037/*NID_kx_rsa()*/;
    //private static final int NID_kx_dhe = NID_kx_dhe();
    //private static final int NID_kx_ecdhe = NID_kx_ecdhe();

    //private static final int NID_auth_rsa = NID_auth_rsa();
    //private static final int NID_auth_dss = NID_auth_dss();
    //private static final int NID_auth_null = NID_auth_null();
    //private static final int NID_auth_ecdsa = NID_auth_ecdsa();

    //private static final int SSL_kRSA = 1;
    private static final int SSL_kDHr = 2;
    private static final int SSL_kDHd = 4;
    private static final int SSL_kEDH = 8;
    private static final int SSL_kDHE = SSL_kEDH;
    private static final int SSL_kKRB5 = 10;
    private static final int SSL_kECDHr = 20;
    private static final int SSL_kECDHe = 40;
    private static final int SSL_kEECDH = 80;
    private static final int SSL_kECDHE = SSL_kEECDH;
    //private static final int SSL_kPSK = 100;
    //private static final int SSL_kGOST = 200;
    //private static final int SSL_kSRP = 400;

    private static final int SSL_aRSA = 1;
    private static final int SSL_aDSS = 2;
    private static final int SSL_aNULL = 4;
    //private static final int SSL_aDH = 8;
    //private static final int SSL_aECDH = 10;
    //private static final int SSL_aKRB5 = 20;
    private static final int SSL_aECDSA = 40;
    //private static final int SSL_aPSK = 80;
    //private static final int SSL_aGOST94 = 100;
    //private static final int SSL_aGOST01 = 200;
    //private static final int SSL_aSRP = 400;

    private static final String SSL_TXT_RSA = "RSA";
    private static final String SSL_TXT_DH = "DH";
    private static final String SSL_TXT_DSS = "DSS";
    private static final String SSL_TXT_KRB5 = "KRB5";
    private static final String SSL_TXT_ECDH = "ECDH";
    private static final String SSL_TXT_ECDSA = "ECDSA";

    private static String getCipherAuthenticationMethod(int auth, int kx) {
        switch (kx) {
        case NID_kx_rsa:
            return SSL_TXT_RSA;
        case SSL_kDHr:
            return SSL_TXT_DH + "_" + SSL_TXT_RSA;
        case SSL_kDHd:
            return SSL_TXT_DH + "_" + SSL_TXT_DSS;
        case SSL_kDHE:
            switch (auth) {
            case SSL_aDSS:
                return "DHE_" + SSL_TXT_DSS;
            case SSL_aRSA:
                return "DHE_" + SSL_TXT_RSA;
            case SSL_aNULL:
                return SSL_TXT_DH + "_anon";
            default:
                return "UNKNOWN";
            }
        case SSL_kKRB5:
            return SSL_TXT_KRB5;
        case SSL_kECDHr:
            return SSL_TXT_ECDH + "_" + SSL_TXT_RSA;
        case SSL_kECDHe:
            return SSL_TXT_ECDH + "_" + SSL_TXT_ECDSA;
        case SSL_kECDHE:
            switch (auth) {
            case SSL_aECDSA:
                return "ECDHE_" + SSL_TXT_ECDSA;
            case SSL_aRSA:
                return "ECDHE_" + SSL_TXT_RSA;
            case SSL_aNULL:
                return SSL_TXT_ECDH + "_anon";
            default:
                return "UNKNOWN";
            }
        default:
            return "UNKNOWN";
        }
    }

    private static class PasswordCallback implements pem_password_cb.Function {
        private final String callbackPassword;
        PasswordCallback(String callbackPassword) {
            this.callbackPassword = callbackPassword;
        }
        @Override
        public int apply(MemorySegment /* char **/ buf, int bufsiz, int verify, MemorySegment /* void **/ cb) {
            if (log.isTraceEnabled()) {
                log.trace("Return password for certificate");
            }
            if (callbackPassword != null && callbackPassword.length() > 0) {
                try (var localArena = Arena.ofConfined()) {
                    MemorySegment callbackPasswordNative = localArena.allocateFrom(callbackPassword);
                    if (callbackPasswordNative.byteSize() > bufsiz) {
                        // The password is too long
                        log.error(sm.getString("openssl.passwordTooLong"));
                    } else {
                        MemorySegment bufSegment = buf.reinterpret(bufsiz, localArena, null);
                        bufSegment.copyFrom(callbackPasswordNative);
                        return (int) callbackPasswordNative.byteSize();
                    }
                }
            }
            return 0;
        }
    }


    private boolean addCertificate(SSLHostConfigCertificate certificate, Arena localArena) throws Exception {
        int index = getCertificateIndex(certificate);
        // Load Server key and certificate
        if (certificate.getCertificateFile() != null) {
            // Pick right key password
            String keyPassToUse = null;
            String keyPass = certificate.getCertificateKeyPassword();
            if (keyPass == null) {
                keyPass = certificate.getCertificateKeystorePassword();
            }
            String keyPassFile = certificate.getCertificateKeyPasswordFile();
            if (keyPassFile == null) {
                keyPassFile = certificate.getCertificateKeystorePasswordFile();
            }
            if (keyPassFile != null) {
                try (BufferedReader reader =
                        new BufferedReader(new InputStreamReader(
                                ConfigFileLoader.getSource().getResource(keyPassFile).getInputStream(),
                                StandardCharsets.UTF_8))) {
                    keyPassToUse = reader.readLine();
                } catch (IOException e) {
                    log.error(sm.getString("openssl.errorLoadingPassword", keyPassFile), e);
                    return false;
                }
            } else {
                keyPassToUse = keyPass;
            }
            // Set certificate
            byte[] certificateFileBytes = null;
            try (Resource resource = ConfigFileLoader.getSource().getResource(certificate.getCertificateFile())) {
                certificateFileBytes = resource.getInputStream().readAllBytes();
            } catch (IOException e) {
                log.error(sm.getString("openssl.errorLoadingCertificate", certificate.getCertificateFile()), e);
                return false;
            }
            MemorySegment certificateFileBytesNative = localArena.allocateFrom(ValueLayout.JAVA_BYTE, certificateFileBytes);
            MemorySegment certificateBIO = BIO_new(BIO_s_mem());
            try {
                if (BIO_write(certificateBIO, certificateFileBytesNative, certificateFileBytes.length) <= 0) {
                    log.error(sm.getString("openssl.errorLoadingCertificateWithError",
                            certificate.getCertificateFile(), OpenSSLLibrary.getLastError()));
                    return false;
                }
                MemorySegment cert = MemorySegment.NULL;
                MemorySegment key = MemorySegment.NULL;
                if (certificate.getCertificateFile().endsWith(".pkcs12")) {
                    // Load pkcs12
                    MemorySegment p12 = d2i_PKCS12_bio(certificateBIO, MemorySegment.NULL);
                    if (MemorySegment.NULL.equals(p12)) {
                        log.error(sm.getString("openssl.errorLoadingCertificateWithError",
                                certificate.getCertificateFile(), OpenSSLLibrary.getLastError()));
                        return false;
                    }
                    MemorySegment passwordAddress = MemorySegment.NULL;
                    int passwordLength = 0;
                    if (keyPassToUse != null && keyPassToUse.length() > 0) {
                        passwordAddress = localArena.allocateFrom(keyPassToUse);
                        passwordLength = (int) (passwordAddress.byteSize() - 1);
                    }
                    if (PKCS12_verify_mac(p12, passwordAddress, passwordLength) <= 0) {
                        // Bad password
                        log.error(sm.getString("openssl.errorLoadingCertificateWithError",
                                certificate.getCertificateFile(), OpenSSLLibrary.getLastError()));
                        PKCS12_free(p12);
                        return false;
                    }
                    MemorySegment certPointer = localArena.allocate(ValueLayout.ADDRESS);
                    MemorySegment keyPointer = localArena.allocate(ValueLayout.ADDRESS);
                    if (PKCS12_parse(p12, passwordAddress, keyPointer, certPointer, MemorySegment.NULL) <= 0) {
                        log.error(sm.getString("openssl.errorLoadingCertificateWithError",
                                certificate.getCertificateFile(), OpenSSLLibrary.getLastError()));
                        PKCS12_free(p12);
                        return false;
                    }
                    PKCS12_free(p12);
                    cert = certPointer.get(ValueLayout.ADDRESS, 0);
                    key = keyPointer.get(ValueLayout.ADDRESS, 0);
                } else {
                    String certificateKeyFileName = (certificate.getCertificateKeyFile() == null)
                            ? certificate.getCertificateFile() : certificate.getCertificateKeyFile();
                    // Load key
                    byte[] certificateKeyFileBytes = null;
                    try (Resource resource = ConfigFileLoader.getSource().getResource(certificateKeyFileName)) {
                        certificateKeyFileBytes = resource.getInputStream().readAllBytes();
                    } catch (IOException e) {
                        log.error(sm.getString("openssl.errorLoadingCertificate", certificateKeyFileName), e);
                        return false;
                    }
                    MemorySegment certificateKeyFileBytesNative = localArena.allocateFrom(ValueLayout.JAVA_BYTE, certificateKeyFileBytes);
                    MemorySegment keyBIO = BIO_new(BIO_s_mem());
                    try {
                        if (BIO_write(keyBIO, certificateKeyFileBytesNative, certificateKeyFileBytes.length) <= 0) {
                            log.error(sm.getString("openssl.errorLoadingCertificateWithError",
                                    certificateKeyFileName, OpenSSLLibrary.getLastError()));
                            return false;
                        }
                        key = MemorySegment.NULL;
                        for (int i = 0; i < 3; i++) {
                            key = PEM_read_bio_PrivateKey(keyBIO, MemorySegment.NULL,
                                    pem_password_cb.allocate(new PasswordCallback(keyPassToUse), contextArena),
                                    MemorySegment.NULL);
                            if (!MemorySegment.NULL.equals(key)) {
                                break;
                            }
                            BIO_reset(keyBIO);
                        }
                    } finally {
                        BIO_free(keyBIO);
                    }
                    if (MemorySegment.NULL.equals(key)) {
                        if (!MemorySegment.NULL.equals(OpenSSLLibrary.enginePointer)) {
                            // This needs a real file
                            key = ENGINE_load_private_key(OpenSSLLibrary.enginePointer,
                                    localArena.allocateFrom(SSLHostConfig.adjustRelativePath(certificateKeyFileName)),
                                    MemorySegment.NULL, MemorySegment.NULL);
                        }
                    }
                    if (MemorySegment.NULL.equals(key)) {
                        log.error(sm.getString("openssl.errorLoadingCertificateWithError",
                                certificateKeyFileName, OpenSSLLibrary.getLastError()));
                        return false;
                    }
                    // Load certificate
                    cert = PEM_read_bio_X509_AUX(certificateBIO, MemorySegment.NULL,
                            pem_password_cb.allocate(new PasswordCallback(keyPassToUse), contextArena),
                            MemorySegment.NULL);
                    if (MemorySegment.NULL.equals(cert) &&
                            // EOF is accepted, then try again
                            ((ERR_peek_last_error() & ERR_REASON_MASK()) == PEM_R_NO_START_LINE())) {
                        ERR_clear_error();
                        BIO_reset(certificateBIO);
                        cert = d2i_X509_bio(certificateBIO, MemorySegment.NULL);
                    }
                    if (MemorySegment.NULL.equals(cert)) {
                        log.error(sm.getString("openssl.errorLoadingCertificateWithError",
                                certificate.getCertificateFile(), OpenSSLLibrary.getLastError()));
                        return false;
                    }
                }
                if (SSL_CTX_use_certificate(state.sslCtx, cert) <= 0) {
                    logLastError("openssl.errorLoadingCertificate");
                    return false;
                }
                if (SSL_CTX_use_PrivateKey(state.sslCtx, key) <= 0) {
                    logLastError("openssl.errorLoadingPrivateKey");
                    return false;
                }
                if (SSL_CTX_check_private_key(state.sslCtx) <= 0) {
                    logLastError("openssl.errorPrivateKeyCheck");
                    return false;
                }
                // Try to read DH parameters from the (first) SSLCertificateFile
                if (index == SSL_AIDX_RSA) {
                    BIO_reset(certificateBIO);
                    if (!openssl_h_Compatibility.BORINGSSL) {
                        if (!openssl_h_Compatibility.OPENSSL3) {
                            var dh = PEM_read_bio_DHparams(certificateBIO, MemorySegment.NULL, MemorySegment.NULL, MemorySegment.NULL);
                            if (!MemorySegment.NULL.equals(dh)) {
                                SSL_CTX_set_tmp_dh(state.sslCtx, dh);
                                DH_free(dh);
                            }
                        } else {
                            var pkey = PEM_read_bio_Parameters(certificateBIO, MemorySegment.NULL);
                            if (!MemorySegment.NULL.equals(pkey)) {
                                int numBits = EVP_PKEY_get_bits(pkey);
                                if (SSL_CTX_set0_tmp_dh_pkey(state.sslCtx, pkey) <= 0) {
                                    EVP_PKEY_free(pkey);
                                } else {
                                    log.debug(sm.getString("openssl.setCustomDHParameters", Integer.valueOf(numBits), certificate.getCertificateFile()));
                                }
                            } else {
                                String errMessage = OpenSSLLibrary.getLastError();
                                if (errMessage != null) {
                                    log.debug(sm.getString("openssl.errorReadingPEMParameters", errMessage, certificate.getCertificateFile()));
                                }
                                SSL_CTX_ctrl(state.sslCtx, SSL_CTRL_SET_DH_AUTO(), 1, MemorySegment.NULL);
                            }
                        }
                    }
                }
                // Similarly, try to read the ECDH curve name from SSLCertificateFile...
                BIO_reset(certificateBIO);
                if (!openssl_h_Compatibility.BORINGSSL) {
                    if (!openssl_h_Compatibility.OPENSSL3) {
                        var ecparams = PEM_read_bio_ECPKParameters(certificateBIO, MemorySegment.NULL, MemorySegment.NULL, MemorySegment.NULL);
                        if (!MemorySegment.NULL.equals(ecparams)) {
                            int nid = EC_GROUP_get_curve_name(ecparams);
                            var eckey = EC_KEY_new_by_curve_name(nid);
                            SSL_CTX_set_tmp_ecdh(state.sslCtx, eckey);
                            EC_KEY_free(eckey);
                            EC_GROUP_free(ecparams);
                        }
                        // Set callback for DH parameters
                        SSL_CTX_set_tmp_dh_callback(state.sslCtx, SSL_CTX_set_tmp_dh_callback$dh.allocate(new TmpDHCallback(), contextArena));
                    } else {
                        var ecparams = PEM_ASN1_read_bio(d2i_ECPKParameters$SYMBOL(),
                                PEM_STRING_ECPARAMETERS(), certificateBIO, MemorySegment.NULL, MemorySegment.NULL, MemorySegment.NULL);
                        if (!MemorySegment.NULL.equals(ecparams)) {
                            int curveNid = EC_GROUP_get_curve_name(ecparams);
                            var curveNidAddress = localArena.allocateFrom(ValueLayout.JAVA_INT, curveNid);
                            if (SSL_CTX_set1_groups(state.sslCtx, curveNidAddress, 1) <= 0) {
                                curveNid = 0;
                            }
                            if (log.isDebugEnabled()) {
                                log.debug(sm.getString("openssl.setECDHCurve", Integer.valueOf(curveNid),
                                        certificate.getCertificateFile()));
                            }
                            EC_GROUP_free(ecparams);
                        }
                    }
                }
                // Set certificate chain file
                if (certificate.getCertificateChainFile() != null) {
                    byte[] certificateChainBytes = null;
                    try (Resource resource = ConfigFileLoader.getSource().getResource(certificate.getCertificateChainFile())) {
                        certificateChainBytes = resource.getInputStream().readAllBytes();
                    } catch (IOException e) {
                        log.error(sm.getString("openssl.errorLoadingCertificate", certificate.getCertificateChainFile()), e);
                        return false;
                    }
                    MemorySegment certificateChainBytesNative = localArena.allocateFrom(ValueLayout.JAVA_BYTE, certificateChainBytes);
                    MemorySegment certificateChainBIO = BIO_new(BIO_s_mem());
                    try {
                        if (BIO_write(certificateChainBIO, certificateChainBytesNative, certificateChainBytes.length) <= 0) {
                            log.error(sm.getString("openssl.errorLoadingCertificateWithError",
                                    certificate.getCertificateChainFile(), OpenSSLLibrary.getLastError()));
                            return false;
                        }
                        MemorySegment certChainEntry =
                                PEM_read_bio_X509_AUX(certificateChainBIO, MemorySegment.NULL, MemorySegment.NULL, MemorySegment.NULL);
                        while (!MemorySegment.NULL.equals(certChainEntry)) {
                            if (SSL_CTX_add0_chain_cert(state.sslCtx, certChainEntry) <= 0) {
                                log.error(sm.getString("openssl.errorLoadingCertificateWithError",
                                        certificate.getCertificateChainFile(), OpenSSLLibrary.getLastError()));
                            }
                            certChainEntry =
                                    PEM_read_bio_X509_AUX(certificateChainBIO, MemorySegment.NULL, MemorySegment.NULL, MemorySegment.NULL);
                        }
                        // EOF is accepted, otherwise log an error
                        if ((ERR_peek_last_error() & ERR_REASON_MASK()) == PEM_R_NO_START_LINE()) {
                            ERR_clear_error();
                        } else {
                            log.error(sm.getString("openssl.errorLoadingCertificateWithError",
                                    certificate.getCertificateChainFile(), OpenSSLLibrary.getLastError()));
                        }
                    } finally {
                        BIO_free(certificateChainBIO);
                    }
                }
                // Set revocation
                MemorySegment certificateStore = SSL_CTX_get_cert_store(state.sslCtx);
                if (sslHostConfig.getCertificateRevocationListFile() != null) {
                    MemorySegment x509Lookup = X509_STORE_add_lookup(certificateStore, X509_LOOKUP_file());
                    var certificateRevocationListFileNative =
                            localArena.allocateFrom(SSLHostConfig.adjustRelativePath(sslHostConfig.getCertificateRevocationListFile()));
                    if (X509_LOOKUP_load_file(x509Lookup, certificateRevocationListFileNative,
                            X509_FILETYPE_PEM()) <= 0) {
                        log.error(sm.getString("openssl.errorLoadingCertificateRevocationListWithError",
                                sslHostConfig.getCertificateRevocationListFile(), OpenSSLLibrary.getLastError()));
                    }
                }
                if (sslHostConfig.getCertificateRevocationListPath() != null) {
                    MemorySegment x509Lookup = X509_STORE_add_lookup(certificateStore, X509_LOOKUP_hash_dir());
                    var certificateRevocationListPathNative =
                            localArena.allocateFrom(SSLHostConfig.adjustRelativePath(sslHostConfig.getCertificateRevocationListPath()));
                    if (X509_LOOKUP_add_dir(x509Lookup, certificateRevocationListPathNative,
                            X509_FILETYPE_PEM()) <= 0) {
                        log.error(sm.getString("openssl.errorLoadingCertificateRevocationListWithError",
                                sslHostConfig.getCertificateRevocationListPath(), OpenSSLLibrary.getLastError()));
                    }
                }
                X509_STORE_set_flags(certificateStore, X509_V_FLAG_CRL_CHECK() | X509_V_FLAG_CRL_CHECK_ALL());
            } finally {
                BIO_free(certificateBIO);
            }
        } else {
            String alias = certificate.getCertificateKeyAlias();
            X509KeyManager x509KeyManager = certificate.getCertificateKeyManager();
            if (alias == null) {
                alias = "tomcat";
            }
            X509Certificate[] chain = x509KeyManager.getCertificateChain(alias);
            if (chain == null) {
                alias = findAlias(x509KeyManager, certificate);
                chain = x509KeyManager.getCertificateChain(alias);
            }
            StringBuilder sb = new StringBuilder(BEGIN_KEY);
            sb.append(Base64.getMimeEncoder(64, new byte[] {'\n'}).encodeToString(x509KeyManager.getPrivateKey(alias).getEncoded()));
            sb.append(END_KEY);
            var rawCertificate = localArena.allocateFrom(ValueLayout.JAVA_BYTE, chain[0].getEncoded());
            var rawCertificatePointer = localArena.allocateFrom(ValueLayout.ADDRESS, rawCertificate);
            var rawKey = localArena.allocateFrom(ValueLayout.JAVA_BYTE, sb.toString().getBytes(StandardCharsets.US_ASCII));
            var x509cert = d2i_X509(MemorySegment.NULL, rawCertificatePointer, rawCertificate.byteSize());
            if (MemorySegment.NULL.equals(x509cert)) {
                logLastError("openssl.errorLoadingCertificate");
                return false;
            }
            MemorySegment keyBIO = BIO_new(BIO_s_mem());
            try {
                BIO_write(keyBIO, rawKey, (int) rawKey.byteSize());
                MemorySegment privateKeyAddress = PEM_read_bio_PrivateKey(keyBIO, MemorySegment.NULL, MemorySegment.NULL, MemorySegment.NULL);
                if (MemorySegment.NULL.equals(privateKeyAddress)) {
                    logLastError("openssl.errorLoadingPrivateKey");
                    return false;
                }
                if (SSL_CTX_use_certificate(state.sslCtx, x509cert) <= 0) {
                    logLastError("openssl.errorLoadingCertificate");
                    return false;
                }
                if (SSL_CTX_use_PrivateKey(state.sslCtx, privateKeyAddress) <= 0) {
                    logLastError("openssl.errorLoadingPrivateKey");
                    return false;
                }
                if (SSL_CTX_check_private_key(state.sslCtx) <= 0) {
                    logLastError("openssl.errorPrivateKeyCheck");
                    return false;
                }
                if (!openssl_h_Compatibility.OPENSSL3) {
                    // Set callback for DH parameters
                    SSL_CTX_set_tmp_dh_callback(state.sslCtx,
                            SSL_CTX_set_tmp_dh_callback$dh.allocate(new TmpDHCallback(), contextArena));
                } else {
                    BIO_reset(keyBIO);
                    var pkey = PEM_read_bio_Parameters(keyBIO, MemorySegment.NULL);
                    if (!MemorySegment.NULL.equals(pkey)) {
                        int numBits = EVP_PKEY_get_bits(pkey);
                        if (SSL_CTX_set0_tmp_dh_pkey(state.sslCtx, pkey) <= 0) {
                            EVP_PKEY_free(pkey);
                        } else {
                            log.debug(sm.getString("openssl.setCustomDHParameters", Integer.valueOf(numBits),
                                    x509KeyManager.toString()));
                        }
                    } else {
                        String errMessage = OpenSSLLibrary.getLastError();
                        if (errMessage != null) {
                            log.debug(sm.getString("openssl.errorReadingPEMParameters", errMessage,
                                    x509KeyManager.toString()));
                        }
                        SSL_CTX_ctrl(state.sslCtx, SSL_CTRL_SET_DH_AUTO(), 1, MemorySegment.NULL);
                    }
                }
                for (int i = 1; i < chain.length; i++) {
                    var rawCertificateChain = localArena.allocateFrom(ValueLayout.JAVA_BYTE, chain[i].getEncoded());
                    var rawCertificateChainPointer = localArena.allocateFrom(ValueLayout.ADDRESS, rawCertificateChain);
                    var x509certChain = d2i_X509(MemorySegment.NULL, rawCertificateChainPointer, rawCertificateChain.byteSize());
                    if (MemorySegment.NULL.equals(x509certChain)) {
                        logLastError("openssl.errorLoadingCertificate");
                        return false;
                    }
                    if (SSL_CTX_add0_chain_cert(state.sslCtx, x509certChain) <= 0) {
                        logLastError("openssl.errorAddingCertificate");
                        return false;
                    }
                }
            } finally {
                BIO_free(keyBIO);
            }
        }
        return true;
    }


    private static int getCertificateIndex(SSLHostConfigCertificate certificate) {
        int result = -1;
        // If the type is undefined there will only be one certificate (enforced
        // in SSLHostConfig) so use the RSA slot.
        if (certificate.getType() == Type.RSA || certificate.getType() == Type.UNDEFINED) {
            result = SSL_AIDX_RSA;
        } else if (certificate.getType() == Type.EC) {
            result = SSL_AIDX_ECC;
        } else if (certificate.getType() == Type.DSA) {
            result = SSL_AIDX_DSA;
        } else {
            result = SSL_AIDX_MAX;
        }
        return result;
    }


    /*
     * Find a valid alias when none was specified in the config.
     */
    private static String findAlias(X509KeyManager keyManager,
            SSLHostConfigCertificate certificate) {

        Type type = certificate.getType();
        String result = null;

        List<Type> candidateTypes = new ArrayList<>();
        if (Type.UNDEFINED.equals(type)) {
            // Try all types to find an suitable alias
            candidateTypes.addAll(Arrays.asList(Type.values()));
            candidateTypes.remove(Type.UNDEFINED);
        } else {
            // Look for the specific type to find a suitable alias
            candidateTypes.add(type);
        }

        Iterator<Type> iter = candidateTypes.iterator();
        while (result == null && iter.hasNext()) {
            result = keyManager.chooseServerAlias(iter.next().toString(),  null,  null);
        }

        return result;
    }

    private static X509TrustManager chooseTrustManager(TrustManager[] managers) {
        for (TrustManager m : managers) {
            if (m instanceof X509TrustManager) {
                return (X509TrustManager) m;
            }
        }
        throw new IllegalStateException(sm.getString("openssl.trustManagerMissing"));
    }

    private static X509Certificate[] certificates(byte[][] chain) {
        X509Certificate[] peerCerts = new X509Certificate[chain.length];
        for (int i = 0; i < peerCerts.length; i++) {
            peerCerts[i] = new OpenSSLX509Certificate(chain[i]);
        }
        return peerCerts;
    }


    private static void logLastError(String string) {
        String message = OpenSSLLibrary.getLastError();
        if (message != null) {
            log.error(sm.getString(string, message));
        }
    }


    @Override
    public SSLSessionContext getServerSessionContext() {
        return sessionContext;
    }

    @Override
    public SSLEngine createSSLEngine() {
        return new OpenSSLEngine(cleaner, state.sslCtx, defaultProtocol, false, sessionContext,
                alpn, initialized,
                sslHostConfig.getCertificateVerificationDepth(),
                sslHostConfig.getCertificateVerification() == CertificateVerification.OPTIONAL_NO_CA,
                noOcspCheck);
    }

    @Override
    public SSLServerSocketFactory getServerSocketFactory() {
        throw new UnsupportedOperationException();
    }

    @Override
    public SSLParameters getSupportedSSLParameters() {
        throw new UnsupportedOperationException();
    }

    @Override
    public X509Certificate[] getCertificateChain(String alias) {
        X509Certificate[] chain = null;
        X509KeyManager x509KeyManager = certificate.getCertificateKeyManager();
        if (x509KeyManager != null) {
            if (alias == null) {
                alias = "tomcat";
            }
            chain = x509KeyManager.getCertificateChain(alias);
            if (chain == null) {
                alias = findAlias(x509KeyManager, certificate);
                chain = x509KeyManager.getCertificateChain(alias);
            }
        }

        return chain;
    }

    @Override
    public X509Certificate[] getAcceptedIssuers() {
        X509Certificate[] acceptedCerts = null;
        if (x509TrustManager != null) {
            acceptedCerts = x509TrustManager.getAcceptedIssuers();
        }
        return acceptedCerts;
    }


    private static class ContextState implements Runnable {

        private final Arena stateArena = Arena.ofShared();
        private final MemorySegment sslCtx;
        private final MemorySegment confCtx;

        private ContextState(MemorySegment sslCtx, MemorySegment confCtx) {
            // Use another arena to avoid keeping a reference through segments
            // This also allows making further accesses to the main pointers safer
            this.sslCtx = sslCtx.reinterpret(ValueLayout.ADDRESS.byteSize(), stateArena,
                    (MemorySegment t) -> SSL_CTX_free(t));
            if (!MemorySegment.NULL.equals(confCtx)) {
                this.confCtx = confCtx.reinterpret(ValueLayout.ADDRESS.byteSize(), stateArena,
                        (MemorySegment t) -> SSL_CONF_CTX_free(t));
            } else {
                this.confCtx = MemorySegment.NULL;
            }
        }

        @Override
        public void run() {
            stateArena.close();
        }
    }
}
