/* 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.
 */

/*                      _             _
 *  _ __ ___   ___   __| |    ___ ___| |  mod_ssl
 * | '_ ` _ \ / _ \ / _` |   / __/ __| |  Apache Interface to OpenSSL
 * | | | | | | (_) | (_| |   \__ \__ \ |
 * |_| |_| |_|\___/ \__,_|___|___/___/_|
 *                      |_____|
 *  ssl_engine_vars.c
 *  Variable Lookup Facility
 */
                             /* ``Those of you who think they
                                  know everything are very annoying
                                  to those of us who do.''
                                                  -- Unknown       */
#include "mod_ssl.h"

/*  _________________________________________________________________
**
**  Variable Lookup
**  _________________________________________________________________
*/

static char *ssl_var_lookup_header(apr_pool_t *p, request_rec *r, const char *name);
static char *ssl_var_lookup_ssl(apr_pool_t *p, conn_rec *c, char *var);
static char *ssl_var_lookup_ssl_cert(apr_pool_t *p, X509 *xs, char *var);
static char *ssl_var_lookup_ssl_cert_dn(apr_pool_t *p, X509_NAME *xsname, char *var);
static char *ssl_var_lookup_ssl_cert_valid(apr_pool_t *p, ASN1_UTCTIME *tm);
static char *ssl_var_lookup_ssl_cert_serial(apr_pool_t *p, X509 *xs);
static char *ssl_var_lookup_ssl_cert_chain(apr_pool_t *p, STACK_OF(X509) *sk, char *var);
static char *ssl_var_lookup_ssl_cert_PEM(apr_pool_t *p, X509 *xs);
static char *ssl_var_lookup_ssl_cert_verify(apr_pool_t *p, conn_rec *c);
static char *ssl_var_lookup_ssl_cipher(apr_pool_t *p, conn_rec *c, char *var);
static void  ssl_var_lookup_ssl_cipher_bits(SSL *ssl, int *usekeysize, int *algkeysize);
static char *ssl_var_lookup_ssl_version(apr_pool_t *p, char *var);

static int ssl_is_https(conn_rec *c)
{
    SSLConnRec *sslconn = myConnConfig(c);
    return sslconn && sslconn->ssl;
}

void ssl_var_register(void)
{
    APR_REGISTER_OPTIONAL_FN(ssl_is_https);
    APR_REGISTER_OPTIONAL_FN(ssl_var_lookup);
    return;
}

/* This function must remain safe to use for a non-SSL connection. */
char *ssl_var_lookup(apr_pool_t *p, server_rec *s, conn_rec *c, request_rec *r, char *var)
{
    SSLModConfigRec *mc = myModConfig(s);
    char *result;
    BOOL resdup;
    apr_time_exp_t tm;

    result = NULL;
    resdup = TRUE;

    /*
     * When no pool is given try to find one
     */
    if (p == NULL) {
        if (r != NULL)
            p = r->pool;
        else if (c != NULL)
            p = c->pool;
        else
            p = mc->pPool;
    }

    /*
     * Request dependent stuff
     */
    if (r != NULL) {
        if (strcEQ(var, "HTTP_USER_AGENT"))
            result = ssl_var_lookup_header(p, r, "User-Agent");
        else if (strcEQ(var, "HTTP_REFERER"))
            result = ssl_var_lookup_header(p, r, "Referer");
        else if (strcEQ(var, "HTTP_COOKIE"))
            result = ssl_var_lookup_header(p, r, "Cookie");
        else if (strcEQ(var, "HTTP_FORWARDED"))
            result = ssl_var_lookup_header(p, r, "Forwarded");
        else if (strcEQ(var, "HTTP_HOST"))
            result = ssl_var_lookup_header(p, r, "Host");
        else if (strcEQ(var, "HTTP_PROXY_CONNECTION"))
            result = ssl_var_lookup_header(p, r, "Proxy-Connection");
        else if (strcEQ(var, "HTTP_ACCEPT"))
            result = ssl_var_lookup_header(p, r, "Accept");
        else if (strlen(var) > 5 && strcEQn(var, "HTTP:", 5))
            /* all other headers from which we are still not know about */
            result = ssl_var_lookup_header(p, r, var+5);
        else if (strcEQ(var, "THE_REQUEST"))
            result = r->the_request;
        else if (strcEQ(var, "REQUEST_METHOD"))
            result = (char *)(r->method);
        else if (strcEQ(var, "REQUEST_SCHEME"))
            result = (char *)ap_http_method(r);
        else if (strcEQ(var, "REQUEST_URI"))
            result = r->uri;
        else if (strcEQ(var, "SCRIPT_FILENAME") ||
                 strcEQ(var, "REQUEST_FILENAME"))
            result = r->filename;
        else if (strcEQ(var, "PATH_INFO"))
            result = r->path_info;
        else if (strcEQ(var, "QUERY_STRING"))
            result = r->args;
        else if (strcEQ(var, "REMOTE_HOST"))
            result = (char *)ap_get_remote_host(r->connection,
					r->per_dir_config, REMOTE_NAME, NULL);
        else if (strcEQ(var, "REMOTE_IDENT"))
            result = (char *)ap_get_remote_logname(r);
        else if (strcEQ(var, "IS_SUBREQ"))
            result = (r->main != NULL ? "true" : "false");
        else if (strcEQ(var, "DOCUMENT_ROOT"))
            result = (char *)ap_document_root(r);
        else if (strcEQ(var, "SERVER_ADMIN"))
            result = r->server->server_admin;
        else if (strcEQ(var, "SERVER_NAME"))
            result = (char *)ap_get_server_name(r);
        else if (strcEQ(var, "SERVER_PORT"))
            result = apr_psprintf(p, "%u", ap_get_server_port(r));
        else if (strcEQ(var, "SERVER_PROTOCOL"))
            result = r->protocol;
    }

    /*
     * Connection stuff
     */
    if (result == NULL && c != NULL) {
        SSLConnRec *sslconn = myConnConfig(c);
        if (strcEQ(var, "REMOTE_ADDR"))
            result = c->remote_ip;
        else if (strcEQ(var, "REMOTE_USER"))
            result = r->user;
        else if (strcEQ(var, "AUTH_TYPE"))
            result = r->ap_auth_type;
        else if (strlen(var) > 4 && strcEQn(var, "SSL_", 4) 
                 && sslconn && sslconn->ssl)
            result = ssl_var_lookup_ssl(p, c, var+4);
        else if (strcEQ(var, "HTTPS")) {
            if (sslconn && sslconn->ssl)
                result = "on";
            else
                result = "off";
        }
    }

    /*
     * Totally independent stuff
     */
    if (result == NULL) {
        if (strlen(var) > 12 && strcEQn(var, "SSL_VERSION_", 12))
            result = ssl_var_lookup_ssl_version(p, var+12);
        else if (strcEQ(var, "SERVER_SOFTWARE"))
            result = (char *)ap_get_server_version();
        else if (strcEQ(var, "API_VERSION")) {
            result = apr_psprintf(p, "%d", MODULE_MAGIC_NUMBER);
            resdup = FALSE;
        }
        else if (strcEQ(var, "TIME_YEAR")) {
            apr_time_exp_lt(&tm, apr_time_now());
            result = apr_psprintf(p, "%02d%02d",
                                 (tm.tm_year / 100) + 19, tm.tm_year % 100);
            resdup = FALSE;
        }
#define MKTIMESTR(format, tmfield) \
            apr_time_exp_lt(&tm, apr_time_now()); \
            result = apr_psprintf(p, format, tm.tmfield); \
            resdup = FALSE;
        else if (strcEQ(var, "TIME_MON")) {
            MKTIMESTR("%02d", tm_mon+1)
        }
        else if (strcEQ(var, "TIME_DAY")) {
            MKTIMESTR("%02d", tm_mday)
        }
        else if (strcEQ(var, "TIME_HOUR")) {
            MKTIMESTR("%02d", tm_hour)
        }
        else if (strcEQ(var, "TIME_MIN")) {
            MKTIMESTR("%02d", tm_min)
        }
        else if (strcEQ(var, "TIME_SEC")) {
            MKTIMESTR("%02d", tm_sec)
        }
        else if (strcEQ(var, "TIME_WDAY")) {
            MKTIMESTR("%d", tm_wday)
        }
        else if (strcEQ(var, "TIME")) {
            apr_time_exp_lt(&tm, apr_time_now());
            result = apr_psprintf(p,
                        "%02d%02d%02d%02d%02d%02d%02d", (tm.tm_year / 100) + 19,
                        (tm.tm_year % 100), tm.tm_mon+1, tm.tm_mday,
                        tm.tm_hour, tm.tm_min, tm.tm_sec);
            resdup = FALSE;
        }
        /* all other env-variables from the parent Apache process */
        else if (strlen(var) > 4 && strcEQn(var, "ENV:", 4)) {
            result = (char *)apr_table_get(r->notes, var+4);
            if (result == NULL)
                result = (char *)apr_table_get(r->subprocess_env, var+4);
            if (result == NULL)
                result = getenv(var+4);
        }
    }

    if (result != NULL && resdup)
        result = apr_pstrdup(p, result);
    if (result == NULL)
        result = "";
    return result;
}

static char *ssl_var_lookup_header(apr_pool_t *p, request_rec *r, const char *name)
{
    char *hdr = NULL;

    if ((hdr = (char *)apr_table_get(r->headers_in, name)) != NULL)
        hdr = apr_pstrdup(p, hdr);
    return hdr;
}

static char *ssl_var_lookup_ssl(apr_pool_t *p, conn_rec *c, char *var)
{
    SSLConnRec *sslconn = myConnConfig(c);
    char *result;
    X509 *xs;
    STACK_OF(X509) *sk;
    SSL *ssl;

    result = NULL;

    ssl = sslconn->ssl;
    if (strlen(var) > 8 && strcEQn(var, "VERSION_", 8)) {
        result = ssl_var_lookup_ssl_version(p, var+8);
    }
    else if (ssl != NULL && strcEQ(var, "PROTOCOL")) {
        result = (char *)SSL_get_version(ssl);
    }
    else if (ssl != NULL && strcEQ(var, "SESSION_ID")) {
        char buf[SSL_SESSION_ID_STRING_LEN];
        SSL_SESSION *pSession = SSL_get_session(ssl);
        if (pSession) {
            result = apr_pstrdup(p, SSL_SESSION_id2sz(
                                     SSL_SESSION_get_session_id(pSession),
                                     SSL_SESSION_get_session_id_length(pSession),
                                     buf, sizeof(buf)));
        }
    }
    else if (ssl != NULL && strlen(var) >= 6 && strcEQn(var, "CIPHER", 6)) {
        result = ssl_var_lookup_ssl_cipher(p, c, var+6);
    }
    else if (ssl != NULL && strlen(var) > 18 && strcEQn(var, "CLIENT_CERT_CHAIN_", 18)) {
        sk = SSL_get_peer_cert_chain(ssl);
        result = ssl_var_lookup_ssl_cert_chain(p, sk, var+18);
    }
    else if (ssl != NULL && strcEQ(var, "CLIENT_VERIFY")) {
        result = ssl_var_lookup_ssl_cert_verify(p, c);
    }
    else if (ssl != NULL && strlen(var) > 7 && strcEQn(var, "CLIENT_", 7)) {
        if ((xs = SSL_get_peer_certificate(ssl)) != NULL) {
            result = ssl_var_lookup_ssl_cert(p, xs, var+7);
            X509_free(xs);
        }
    }
    else if (ssl != NULL && strlen(var) > 7 && strcEQn(var, "SERVER_", 7)) {
        if ((xs = SSL_get_certificate(ssl)) != NULL)
            result = ssl_var_lookup_ssl_cert(p, xs, var+7);
    }
    return result;
}

static char *ssl_var_lookup_ssl_cert(apr_pool_t *p, X509 *xs, char *var)
{
    char *result;
    BOOL resdup;
    X509_NAME *xsname;
    int nid;
    char *cp;

    result = NULL;
    resdup = TRUE;

    if (strcEQ(var, "M_VERSION")) {
        result = apr_psprintf(p, "%lu", X509_get_version(xs)+1);
        resdup = FALSE;
    }
    else if (strcEQ(var, "M_SERIAL")) {
        result = ssl_var_lookup_ssl_cert_serial(p, xs);
    }
    else if (strcEQ(var, "V_START")) {
        result = ssl_var_lookup_ssl_cert_valid(p, X509_get_notBefore(xs));
    }
    else if (strcEQ(var, "V_END")) {
        result = ssl_var_lookup_ssl_cert_valid(p, X509_get_notAfter(xs));
    }
    else if (strcEQ(var, "S_DN")) {
        xsname = X509_get_subject_name(xs);
        cp = X509_NAME_oneline(xsname, NULL, 0);
        result = apr_pstrdup(p, cp);
        modssl_free(cp);
        resdup = FALSE;
    }
    else if (strlen(var) > 5 && strcEQn(var, "S_DN_", 5)) {
        xsname = X509_get_subject_name(xs);
        result = ssl_var_lookup_ssl_cert_dn(p, xsname, var+5);
        resdup = FALSE;
    }
    else if (strcEQ(var, "I_DN")) {
        xsname = X509_get_issuer_name(xs);
        cp = X509_NAME_oneline(xsname, NULL, 0);
        result = apr_pstrdup(p, cp);
        modssl_free(cp);
        resdup = FALSE;
    }
    else if (strlen(var) > 5 && strcEQn(var, "I_DN_", 5)) {
        xsname = X509_get_issuer_name(xs);
        result = ssl_var_lookup_ssl_cert_dn(p, xsname, var+5);
        resdup = FALSE;
    }
    else if (strcEQ(var, "A_SIG")) {
        nid = OBJ_obj2nid((ASN1_OBJECT *)X509_get_signature_algorithm(xs));
        result = apr_pstrdup(p, 
                             (nid == NID_undef) ? "UNKNOWN" : OBJ_nid2ln(nid));
        resdup = FALSE;
    }
    else if (strcEQ(var, "A_KEY")) {
        nid = OBJ_obj2nid((ASN1_OBJECT *)X509_get_key_algorithm(xs));
        result = apr_pstrdup(p,
                             (nid == NID_undef) ? "UNKNOWN" : OBJ_nid2ln(nid));
        resdup = FALSE;
    }
    else if (strcEQ(var, "CERT")) {
        result = ssl_var_lookup_ssl_cert_PEM(p, xs);
    }

    if (result != NULL && resdup)
        result = apr_pstrdup(p, result);
    return result;
}

static const struct {
    char *name;
    int   nid;
} ssl_var_lookup_ssl_cert_dn_rec[] = {
    { "C",     NID_countryName            },
    { "ST",    NID_stateOrProvinceName    }, /* officially    (RFC2156) */
    { "SP",    NID_stateOrProvinceName    }, /* compatibility (SSLeay)  */
    { "L",     NID_localityName           },
    { "O",     NID_organizationName       },
    { "OU",    NID_organizationalUnitName },
    { "CN",    NID_commonName             },
    { "T",     NID_title                  },
    { "I",     NID_initials               },
    { "G",     NID_givenName              },
    { "S",     NID_surname                },
    { "D",     NID_description            },
/* This has been removed in OpenSSL 0.9.8-dev. */
#ifdef NID_uniqueIdentifier
    { "UID",   NID_uniqueIdentifier       },
#endif
    { "Email", NID_pkcs9_emailAddress     },
    { NULL,    0                          }
};

static char *ssl_var_lookup_ssl_cert_dn(apr_pool_t *p, X509_NAME *xsname, char *var)
{
    char *result;
    X509_NAME_ENTRY *xsne;
    int i, j, n;
    unsigned char *data_ptr;
    int data_len;

    result = NULL;

    for (i = 0; ssl_var_lookup_ssl_cert_dn_rec[i].name != NULL; i++) {
        if (strEQ(var, ssl_var_lookup_ssl_cert_dn_rec[i].name)) {
            for (j = 0; j < sk_X509_NAME_ENTRY_num((STACK_OF(X509_NAME_ENTRY) *)
                                                 X509_NAME_get_entries(xsname));
                 j++) {
                xsne = sk_X509_NAME_ENTRY_value((STACK_OF(X509_NAME_ENTRY) *)
                                             X509_NAME_get_entries(xsname), j);

                n =OBJ_obj2nid((ASN1_OBJECT *)X509_NAME_ENTRY_get_object(xsne));
                data_ptr = X509_NAME_ENTRY_get_data_ptr(xsne);
                data_len = X509_NAME_ENTRY_get_data_len(xsne);

                if (n == ssl_var_lookup_ssl_cert_dn_rec[i].nid) {
                    result = apr_palloc(p, data_len+1);
                    apr_cpystrn(result, (char *)data_ptr, data_len+1);
#ifdef CHARSET_EBCDIC
                    ascii2ebcdic(result, result, xsne->value->length);
#endif /* CHARSET_EBCDIC */
                    result[data_len] = NUL;
                    break;
                }
            }
            break;
        }
    }
    return result;
}

static char *ssl_var_lookup_ssl_cert_valid(apr_pool_t *p, ASN1_UTCTIME *tm)
{
    char *result;
    BIO* bio;
    int n;

    if ((bio = BIO_new(BIO_s_mem())) == NULL)
        return NULL;
    ASN1_UTCTIME_print(bio, tm);
    n = BIO_pending(bio);
    result = apr_pcalloc(p, n+1);
    n = BIO_read(bio, result, n);
    result[n] = NUL;
    BIO_free(bio);
    return result;
}

static char *ssl_var_lookup_ssl_cert_serial(apr_pool_t *p, X509 *xs)
{
    char *result;
    BIO *bio;
    int n;

    if ((bio = BIO_new(BIO_s_mem())) == NULL)
        return NULL;
    i2a_ASN1_INTEGER(bio, X509_get_serialNumber(xs));
    n = BIO_pending(bio);
    result = apr_pcalloc(p, n+1);
    n = BIO_read(bio, result, n);
    result[n] = NUL;
    BIO_free(bio);
    return result;
}

static char *ssl_var_lookup_ssl_cert_chain(apr_pool_t *p, STACK_OF(X509) *sk, char *var)
{
    char *result;
    X509 *xs;
    int n;

    result = NULL;

    if (strspn(var, "0123456789") == strlen(var)) {
        n = atoi(var);
        if (n < sk_X509_num(sk)) {
            xs = sk_X509_value(sk, n);
            result = ssl_var_lookup_ssl_cert_PEM(p, xs);
        }
    }

    return result;
}

static char *ssl_var_lookup_ssl_cert_PEM(apr_pool_t *p, X509 *xs)
{
    char *result;
    BIO *bio;
    int n;

    if ((bio = BIO_new(BIO_s_mem())) == NULL)
        return NULL;
    PEM_write_bio_X509(bio, xs);
    n = BIO_pending(bio);
    result = apr_pcalloc(p, n+1);
    n = BIO_read(bio, result, n);
    result[n] = NUL;
    BIO_free(bio);
    return result;
}

static char *ssl_var_lookup_ssl_cert_verify(apr_pool_t *p, conn_rec *c)
{
    SSLConnRec *sslconn = myConnConfig(c);
    char *result;
    long vrc;
    const char *verr;
    const char *vinfo;
    SSL *ssl;
    X509 *xs;

    result = NULL;
    ssl   = sslconn->ssl;
    verr  = sslconn->verify_error;
    vinfo = sslconn->verify_info;
    vrc   = SSL_get_verify_result(ssl);
    xs    = SSL_get_peer_certificate(ssl);

    if (vrc == X509_V_OK && verr == NULL && vinfo == NULL && xs == NULL)
        /* no client verification done at all */
        result = "NONE";
    else if (vrc == X509_V_OK && verr == NULL && vinfo == NULL && xs != NULL)
        /* client verification done successful */
        result = "SUCCESS";
    else if (vrc == X509_V_OK && vinfo != NULL && strEQ(vinfo, "GENEROUS"))
        /* client verification done in generous way */
        result = "GENEROUS";
    else
        /* client verification failed */
        result = apr_psprintf(p, "FAILED:%s", verr);

    if (xs)
        X509_free(xs);
    return result;
}

static char *ssl_var_lookup_ssl_cipher(apr_pool_t *p, conn_rec *c, char *var)
{
    SSLConnRec *sslconn = myConnConfig(c);    
    char *result;
    BOOL resdup;
    int usekeysize, algkeysize;
    SSL *ssl;

    result = NULL;
    resdup = TRUE;

    ssl = sslconn->ssl;
    ssl_var_lookup_ssl_cipher_bits(ssl, &usekeysize, &algkeysize);

    if (ssl && strEQ(var, "")) {
        SSL_CIPHER *cipher = SSL_get_current_cipher(ssl);
        result = (cipher != NULL ? (char *)SSL_CIPHER_get_name(cipher) : NULL);
    }
    else if (strcEQ(var, "_EXPORT"))
        result = (usekeysize < 56 ? "true" : "false");
    else if (strcEQ(var, "_USEKEYSIZE")) {
        result = apr_psprintf(p, "%d", usekeysize);
        resdup = FALSE;
    }
    else if (strcEQ(var, "_ALGKEYSIZE")) {
        result = apr_psprintf(p, "%d", algkeysize);
        resdup = FALSE;
    }

    if (result != NULL && resdup)
        result = apr_pstrdup(p, result);
    return result;
}

static void ssl_var_lookup_ssl_cipher_bits(SSL *ssl, int *usekeysize, int *algkeysize)
{
    SSL_CIPHER *cipher;

    *usekeysize = 0;
    *algkeysize = 0;
    if (ssl != NULL)
        if ((cipher = SSL_get_current_cipher(ssl)) != NULL)
            *usekeysize = SSL_CIPHER_get_bits(cipher, algkeysize);
    return;
}

static char *ssl_var_lookup_ssl_version(apr_pool_t *p, char *var)
{
    char *result;
    char *cp, *cp2;

    result = NULL;

    if (strEQ(var, "PRODUCT")) {
#if defined(SSL_PRODUCT_NAME) && defined(SSL_PRODUCT_VERSION)
        result = apr_psprintf(p, "%s/%s", SSL_PRODUCT_NAME, SSL_PRODUCT_VERSION);
#else
        result = NULL;
#endif
    }
    else if (strEQ(var, "INTERFACE")) {
        result = apr_psprintf(p, "mod_ssl/%s", MOD_SSL_VERSION);
    }
    else if (strEQ(var, "LIBRARY")) {
        result = apr_pstrdup(p, SSLeay_version(SSLEAY_VERSION));
        if ((cp = strchr(result, ' ')) != NULL) {
            *cp = '/';
            if ((cp2 = strchr(cp, ' ')) != NULL)
                *cp2 = NUL;
        }
    }
    return result;
}

/*  _________________________________________________________________
**
**  SSL Extension to mod_log_config
**  _________________________________________________________________
*/

#include "../../modules/loggers/mod_log_config.h"

static const char *ssl_var_log_handler_c(request_rec *r, char *a);
static const char *ssl_var_log_handler_x(request_rec *r, char *a);

/*
 * register us for the mod_log_config function registering phase
 * to establish %{...}c and to be able to expand %{...}x variables.
 */
void ssl_var_log_config_register(apr_pool_t *p)
{
    static APR_OPTIONAL_FN_TYPE(ap_register_log_handler) *log_pfn_register;

    log_pfn_register = APR_RETRIEVE_OPTIONAL_FN(ap_register_log_handler);

    if (log_pfn_register) {
        log_pfn_register(p, "c", ssl_var_log_handler_c, 0);
        log_pfn_register(p, "x", ssl_var_log_handler_x, 0);
    }
    return;
}

/*
 * implement the %{..}c log function
 * (we are the only function)
 */
static const char *ssl_var_log_handler_c(request_rec *r, char *a)
{
    SSLConnRec *sslconn = myConnConfig(r->connection);
    char *result;

    if (sslconn == NULL || sslconn->ssl == NULL)
        return NULL;
    result = NULL;
    if (strEQ(a, "version"))
        result = ssl_var_lookup(r->pool, r->server, r->connection, r, "SSL_PROTOCOL");
    else if (strEQ(a, "cipher"))
        result = ssl_var_lookup(r->pool, r->server, r->connection, r, "SSL_CIPHER");
    else if (strEQ(a, "subjectdn") || strEQ(a, "clientcert"))
        result = ssl_var_lookup(r->pool, r->server, r->connection, r, "SSL_CLIENT_S_DN");
    else if (strEQ(a, "issuerdn") || strEQ(a, "cacert"))
        result = ssl_var_lookup(r->pool, r->server, r->connection, r, "SSL_CLIENT_I_DN");
    else if (strEQ(a, "errcode"))
        result = "-";
    else if (strEQ(a, "errstr"))
        result = (char *)sslconn->verify_error;
    if (result != NULL && result[0] == NUL)
        result = NULL;
    return result;
}

/*
 * extend the implementation of the %{..}x log function
 * (there can be more functions)
 */
static const char *ssl_var_log_handler_x(request_rec *r, char *a)
{
    char *result;

    result = ssl_var_lookup(r->pool, r->server, r->connection, r, a);
    if (result != NULL && result[0] == NUL)
        result = NULL;
    return result;
}

