/* Licensed to Stichting The Commons Conservancy (TCC) under one or more
 * contributor license agreements.  See the AUTHORS file distributed with
 * this work for additional information regarding copyright ownership.
 * TCC 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.
 */

/*
 * Provider to save certificate sign requests to disk.
 *
 *  Author: Graham Leggett
 *
 */
#include <apr_strings.h>
#include <apr_hash.h>
#include <apr_lib.h>

#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/txt_db.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>

#include "httpd.h"
#include "http_config.h"
#include "http_core.h"
#include "http_log.h"
#include "http_protocol.h"
#include "http_request.h"
#include "util_mutex.h"
#include "util_script.h"

#include "mod_ca.h"

#undef PACKAGE_BUGREPORT
#undef PACKAGE_NAME
#undef PACKAGE_STRING
#undef PACKAGE_TARNAME
#undef PACKAGE_VERSION
#include "config.h"

#define SERIAL_RAND_BITS 64

#define DEFAULT_SERIAL_SUFFIX "pem"
#define DEFAULT_TRANSACTION_SUFFIX "cert"

#define DB_type         0
#define DB_exp_date     1
#define DB_rev_date     2
#define DB_serial       3       /* index - unique */
#define DB_file         4
#define DB_name         5       /* index - unique when active and not disabled */
#define DB_NUMBER       6

#define DB_TYPE_REV     'R'
#define DB_TYPE_EXP     'E'
#define DB_TYPE_VAL     'V'

module AP_MODULE_DECLARE_DATA ca_disk_module;

typedef struct
{
    const char *csr_path;
    const char *serial_path;
    const char *serial_path_suffix;
    const char *transaction_path;
    const char *transaction_path_suffix;
    const char *serial_file;
    const char *index_file;
    const char *chain_file;
    int index_unique;
    int csr_path_set :1;
    int serial_path_set :1;
    int transaction_path_set :1;
    int serial_file_set :1;
    int index_file_set :1;
    int index_unique_set :1;
    int chain_set :1;
} ca_config_rec;

struct ap_ca_instance_t
{
    void *placeholder;
};

typedef struct
{
    int nid;
    char *oid;
    char *name1;
    char *name2;
} niddef_t;
#define NEW_NIDS        1
static niddef_t scep_oid_def[NEW_NIDS] =
{
{ -1, "2.16.840.1.113733.1.9.7", "transactionID", "transactionID" } };

static unsigned long index_serial_hash(const OPENSSL_CSTRING *a)
{
    const char *n;

    n = a[DB_serial];
    while (*n == '0')
        n++;
    return (lh_strhash(n));
}

static int index_serial_cmp(const OPENSSL_CSTRING *a, const OPENSSL_CSTRING *b)
{
    const char *aa, *bb;

    for (aa = a[DB_serial]; *aa == '0'; aa++)
        ;
    for (bb = b[DB_serial]; *bb == '0'; bb++)
        ;
    return (strcmp(aa, bb));
}

static int index_name_qual(char **a)
{
    return (a[0][0] == 'V');
}

static unsigned long index_name_hash(const OPENSSL_CSTRING *a)
{
    return (lh_strhash(a[DB_name]));
}

int index_name_cmp(const OPENSSL_CSTRING *a, const OPENSSL_CSTRING *b)
{
    return (strcmp(a[DB_name], b[DB_name]));
}

static IMPLEMENT_LHASH_HASH_FN(index_serial, OPENSSL_CSTRING)
static IMPLEMENT_LHASH_COMP_FN(index_serial, OPENSSL_CSTRING)
static IMPLEMENT_LHASH_HASH_FN(index_name, OPENSSL_CSTRING)
static IMPLEMENT_LHASH_COMP_FN(index_name, OPENSSL_CSTRING)

apr_global_mutex_t *ca_disk_mutex; /* Lock around shared memory segment access */
static const char *ca_disk_mutex_type = "ca_disk_mutex_type";

static void log_message(request_rec *r, apr_status_t status,
        const char *message)
{
    int len;
    BIO *mem = BIO_new(BIO_s_mem());
    char *err = apr_palloc(r->pool, HUGE_STRING_LEN);

    ERR_print_errors(mem);

    len = BIO_gets(mem, err, HUGE_STRING_LEN - 1);
    if (len > -1) {
        err[len] = 0;
    }

    apr_table_setn(r->notes, "error-notes",
            apr_pstrcat(r->pool, "Disk: ", ap_escape_html(
                    r->pool, message), NULL));

    /* Allow "error-notes" string to be printed by ap_send_error_response() */
    apr_table_setn(r->notes, "verbose-error-to", "*");

    if (len > 0) {
        ap_log_rerror(
                APLOG_MARK, APLOG_ERR, status, r, "mod_ca_disk: "
                "%s (%s)", message, err);
    }
    else {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, "mod_ca_disk: "
            "%s", message);
    }

    BIO_free(mem);
}

static apr_status_t ca_PKCS7_cleanup(void *data)
{
    PKCS7_free((PKCS7 *) data);
    return APR_SUCCESS;
}

static apr_status_t ca_sk_X509_cleanup(void *data)
{
    sk_X509_free((STACK_OF(X509) *) data);
    return APR_SUCCESS;
}

static apr_status_t ca_X509_REQ_cleanup(void *data)
{
    X509_REQ_free((X509_REQ *) data);
    return APR_SUCCESS;
}

static apr_status_t ca_X509_NAME_cleanup(void *data)
{
    X509_NAME_free((X509_NAME *) data);
    return APR_SUCCESS;
}

static apr_status_t ca_BIO_cleanup(void *data)
{
    BIO_free((BIO *) data);
    return APR_SUCCESS;
}

static apr_status_t ca_ASN1_STRING_cleanup(void *data)
{
    ASN1_PRINTABLE_free((ASN1_STRING *) data);
    return APR_SUCCESS;
}

static apr_status_t ca_ASN1_TIME_cleanup(void *data)
{
    ASN1_TIME_free((ASN1_TIME *) data);
    return APR_SUCCESS;
}

static apr_status_t ca_ASN1_INTEGER_cleanup(void *data)
{
    ASN1_INTEGER_free((ASN1_INTEGER *) data);
    return APR_SUCCESS;
}

static apr_status_t ca_BIGNUM_cleanup(void *data)
{
    BN_free((BIGNUM *) data);
    return APR_SUCCESS;
}

static apr_status_t ca_TXT_DB_cleanup(void *data)
{
    TXT_DB_free((TXT_DB *) data);
    return APR_SUCCESS;
}

static ASN1_STRING *parse_ASN1_STRING(apr_pool_t *pool, ca_asn1_t *string)
{
    ASN1_STRING *s = NULL;
    if (string) {
        d2i_ASN1_PRINTABLE(&s, &string->val, string->len);
        if (s) {
            apr_pool_cleanup_register(pool, s, ca_ASN1_STRING_cleanup,
                    apr_pool_cleanup_null);
        }
    }
    return s;
}

static ASN1_TIME *parse_ASN1_TIME(apr_pool_t *pool, ca_asn1_t *time)
{
    ASN1_TIME *t = NULL;
    if (time) {
        d2i_ASN1_TIME(&t, &time->val, time->len);
        if (t) {
            apr_pool_cleanup_register(pool, t, ca_ASN1_TIME_cleanup,
                    apr_pool_cleanup_null);
        }
    }
    return t;
}

static ASN1_INTEGER *parse_ASN1_INTEGER(apr_pool_t *pool, ca_asn1_t *integer)
{
    ASN1_INTEGER *i = NULL;
    if (integer) {
        d2i_ASN1_INTEGER(&i, &integer->val, integer->len);
        if (i) {
            apr_pool_cleanup_register(pool, i, ca_ASN1_INTEGER_cleanup,
                    apr_pool_cleanup_null);
        }
    }
    return i;
}

static X509_NAME *parse_X509_NAME(apr_pool_t *pool, ca_asn1_t *name)
{
    X509_NAME *n = NULL;
    if (name) {
        d2i_X509_NAME(&n, &name->val, name->len);
        if (n) {
            apr_pool_cleanup_register(pool, n, ca_X509_NAME_cleanup,
                    apr_pool_cleanup_null);
        }
    }
    return n;
}

/* Prevent anything untowards in a filename; by replacing
 * any non alpanums by a _<hex> construct.
 */
static const char * safe_filename(apr_pool_t *pool, const char * fname) 
{
	const char hex[16] = "0123456789ABCDEF";
	char * out = NULL, * o;

	if (fname == NULL)
		return "_";

	if (!*fname)
		return "_00";

	// worst case lenght; including trailing \0.
	out = apr_palloc(pool, 1 + strlen(fname) * 3);

        o = out;
	for(const char *p = fname; *p; p++) 
	{
		if (apr_isalnum(*p)) 
		{
			*o++ = *p;
			continue;
		};
		*o++ = '_';
		*o++ = hex[ ( *p >> 4)  & 0xF ];
		*o++ = hex[ ( *p >> 0)  & 0xF ];
	};
	return out;
}

static int ca_sign_disk(request_rec *r, apr_hash_t *params,
        const unsigned char **buffer, apr_size_t *len)
{
    X509_REQ *creq = NULL;
    const unsigned char *tmp = *buffer;
    int idx;

    ca_config_rec *conf = ap_get_module_config(r->per_dir_config,
            &ca_disk_module);

    /* path to csr directory defined? */
    if (!conf->csr_path) {
        return DECLINED;
    }

    /* read in the certificate request */
    if (!d2i_X509_REQ(&creq, &tmp, *len)) {
        log_message(r, APR_SUCCESS,
                "could not DER decode the certificate to be signed");

        return HTTP_BAD_REQUEST;
    }
    apr_pool_cleanup_register(r->pool, creq, ca_X509_REQ_cleanup,
            apr_pool_cleanup_null);

    /* handle the transaction_id if present */
    idx = X509_REQ_get_attr_by_NID(creq, OBJ_sn2nid("transactionID"), -1);
    if (idx == -1) {

        /* Note: In the absence of a transactionID, it would be nice to use either
         * the CN, or the subjectAltName, or the subject for this, or perhaps a hash
         * of some kind. All in good time.
         */

        log_message(r, APR_SUCCESS,
                "mod_ca frontend did not supply a transaction ID, it is required");

        return HTTP_BAD_REQUEST;
    }
    else {
        apr_off_t offset;
        char buf[HUGE_STRING_LEN];
        BIO *out;
        char *tname, *fname;
        apr_status_t status;
        apr_file_t *temp;
        ASN1_PRINTABLESTRING *str;
        const char *transaction_id;
        X509_ATTRIBUTE *attr = X509_REQ_get_attr(creq, idx);
        if (X509_ATTRIBUTE_count(attr) != 1) {
            log_message(r, APR_SUCCESS,
                    "the transaction ID must have a single value");

            return HTTP_BAD_REQUEST;
        }
        str = X509_ATTRIBUTE_get0_data(attr, 0, V_ASN1_PRINTABLESTRING, NULL);
        if (!str) {
            log_message(r, APR_SUCCESS,
                    "the transaction ID must be a printable string");

            return HTTP_BAD_REQUEST;
        }
        transaction_id = apr_pstrndup(r->pool, (const char *) str->data,
                str->length);

        /* create a bio for our CSR */
        out = BIO_new(BIO_s_mem());
        apr_pool_cleanup_register(r->pool, out, ca_BIO_cleanup,
                apr_pool_cleanup_null);

        if (!X509_REQ_print(out, creq)) {
            log_message(r, APR_SUCCESS, "CSR summary could not generated");

            return HTTP_INTERNAL_SERVER_ERROR;
        }
        if (!PEM_write_bio_X509_REQ(out, creq)) {
            log_message(r, APR_SUCCESS, "CSR could not be PEM encoded");

            return HTTP_INTERNAL_SERVER_ERROR;
        }

        /* try write away the CSR as a PEM file */
        status = apr_filepath_merge(&fname, conf->csr_path,
                apr_pstrcat(r->pool, safe_filename(r->pool, transaction_id), ".csr", NULL),
                APR_FILEPATH_SECUREROOT | APR_FILEPATH_NOTRELATIVE, r->pool);
        if (APR_SUCCESS != status) {
            log_message(r, status, "The CSR path must be a valid path");

            return HTTP_INTERNAL_SERVER_ERROR;
        }
        status = apr_filepath_merge(&tname, conf->csr_path, "csr.XXXXXX",
                APR_FILEPATH_SECUREROOT | APR_FILEPATH_NOTRELATIVE, r->pool);
        if (APR_SUCCESS != status) {
            log_message(r, status, "The CSR path must be a valid path");

            return HTTP_INTERNAL_SERVER_ERROR;
        }
        status = apr_file_mktemp(&temp, tname,
                APR_CREATE | APR_WRITE | APR_EXCL, r->pool);
        if (APR_SUCCESS != status) {
            log_message(r, status, "Could not create the CSR temporary file");

            return HTTP_INTERNAL_SERVER_ERROR;
        }

        /* write away the CSR */
        while ((offset = BIO_read(out, buf, sizeof(buf))) > 0) {
            status = apr_file_write_full(temp, buf, offset, NULL);
            if (APR_SUCCESS != status) {
                log_message(r, status,
                        "Could not write to the CSR temporary file");

                apr_file_close(temp);
                apr_file_remove(tname, r->pool);
                return HTTP_INTERNAL_SERVER_ERROR;
            }
        }
        status = apr_file_close(temp);
        if (APR_SUCCESS != status) {
            log_message(r, status, "Could not write to the CSR temporary file");

            apr_file_remove(tname, r->pool);
            return HTTP_INTERNAL_SERVER_ERROR;
        }

        /* rename the file into place */
        status = apr_file_rename(tname, fname, r->pool);
        if (APR_SUCCESS != status) {
            log_message(r, status, "Could not rename the CSR temporary file");

            apr_file_remove(tname, r->pool);
            return HTTP_INTERNAL_SERVER_ERROR;
        }
    }

    return DONE;
}

static int ca_certstore_disk(request_rec *r, apr_hash_t *params,
        const unsigned char *buffer, apr_size_t len)
{
    const unsigned char *tmp = buffer;
    char *path = NULL, *link = NULL;
    BIO *out;
    char *tname;
    apr_file_t *temp;
    apr_off_t offset;
    char buf[HUGE_STRING_LEN];
    X509 *cert = NULL;
    PKCS7 *p7 = NULL;
    apr_status_t status;

    ca_config_rec *conf = ap_get_module_config(r->per_dir_config,
            &ca_disk_module);

    /* certificate path defined? */
    if (!conf->serial_path && !conf->transaction_path) {
        return DECLINED;
    }

    /* read in the certificates */
    if (!d2i_PKCS7(&p7, &tmp, len)) {
        log_message(r, APR_SUCCESS,
                "could not DER decode the PKCS7 certificate to be stored");

        return HTTP_BAD_REQUEST;
    }
    apr_pool_cleanup_register(r->pool, cert, ca_PKCS7_cleanup,
            apr_pool_cleanup_null);

    /* grab the first certificate */
    if (OBJ_obj2nid(p7->type) == NID_pkcs7_signed) {
        STACK_OF(X509) *certs = p7->d.sign->cert;
        if (sk_X509_num(certs)) {
            cert = sk_X509_value(certs, 0);
        }
        else {
            log_message(r, APR_SUCCESS,
                    "PKCS7 contained zero certificates, nothing to store");

            return HTTP_BAD_REQUEST;
        }
    }
    else {
        log_message(r, APR_SUCCESS,
                "PKCS7 was not signedData, nothing to store");

        return HTTP_BAD_REQUEST;
    }

    /* extract the serial if requested */
    if (conf->serial_path) {
        const char *key;
        BIGNUM *bn = NULL;
        ASN1_INTEGER *si = X509_get_serialNumber(cert);
        if (!si) {
            log_message(r, APR_SUCCESS,
                    "certificate had no serial number, could not be stored");

            return HTTP_BAD_REQUEST;
        }
        bn = ASN1_INTEGER_to_BN(si, NULL);
        if (BN_is_zero(bn)) {
            key = apr_pstrcat(r->pool, "00.", conf->serial_path_suffix, NULL);
        }
        else {
            char *tmp = BN_bn2hex(bn);
            key = apr_pstrcat(r->pool, tmp, ".", conf->serial_path_suffix,
                    NULL);
            OPENSSL_free(tmp);
        }
        BN_free(bn);

        /* set up the path */
        status = apr_filepath_merge(&path, conf->serial_path, key,
                APR_FILEPATH_SECUREROOT | APR_FILEPATH_NOTRELATIVE, r->pool);
        if (APR_SUCCESS != status) {
            log_message(r, status,
                    apr_psprintf(r->pool,
                            "The CADiskCertificateBySerialPath could not be merged with: %s",
                            key));

            return HTTP_INTERNAL_SERVER_ERROR;
        }

    }

    /* extract the transactionID if requested */
    if (conf->transaction_path) {
        const char *key;
        ca_asn1_t *transaction_id;

        transaction_id =
                params ? apr_hash_get(params, "transactionID",
                        APR_HASH_KEY_STRING) :
                        NULL;
        if (transaction_id) {
	    const char * kid;
            ASN1_STRING *s = parse_ASN1_STRING(r->pool, transaction_id);
            if (!s) {
                log_message(r, status, "The transactionID could not be parsed");

                return HTTP_BAD_REQUEST;
            }
	    if (conf->serial_path)
        	ap_log_rerror( APLOG_MARK, APLOG_WARNING, APR_SUCCESS, r, 
			"Both serial and transaction path defined; using the latter.");

#if HAVE_ASN1_STRING_GET0_DATA
	    kid = (const char *) ASN1_STRING_get0_data(s);
#else
            kid = (const char *) ASN1_STRING_data(s);
#endif
            key = apr_pstrcat(r->pool,
                        apr_pstrndup(r->pool, safe_filename(r->pool,kid),
                                ASN1_STRING_length(s)), ".",
                        conf->transaction_path_suffix, NULL);

            /* set up the path */
            status = apr_filepath_merge(path ? &link : &path,
                    conf->transaction_path, key,
                    APR_FILEPATH_SECUREROOT | APR_FILEPATH_NOTRELATIVE,
                    r->pool);
            if (APR_SUCCESS != status) {
                log_message(r, status,
                        apr_psprintf(r->pool,
                                "The CADiskCertificateByTransactionPath could not be merged with: %s",
                                key));

                return HTTP_INTERNAL_SERVER_ERROR;
            }

        }
    }

    /* no path isolated? not for us */
    if (!path) {
        return DECLINED;
    }

    /* create a bio for our CSR */
    out = BIO_new(BIO_s_mem());
    apr_pool_cleanup_register(r->pool, out, ca_BIO_cleanup,
            apr_pool_cleanup_null);

    if (!X509_print(out, cert)) {
        log_message(r, APR_SUCCESS, "Certificate summary could not generated");

        return HTTP_INTERNAL_SERVER_ERROR;
    }
    if (!PEM_write_bio_X509(out, cert)) {
        log_message(r, APR_SUCCESS, "Certificate could not be PEM encoded");

        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* try write away the certificate as a PEM file */
    tname = apr_pstrcat(r->pool, path, ".XXXXXX", NULL);
    status = apr_file_mktemp(&temp, tname, APR_CREATE | APR_WRITE | APR_EXCL,
            r->pool);
    if (APR_SUCCESS != status) {
        log_message(r, status,
                "Could not create the certificate temporary file");

        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* write away the buffer */
    while ((offset = BIO_read(out, buf, sizeof(buf))) > 0) {
        status = apr_file_write_full(temp, buf, offset, NULL);
        if (APR_SUCCESS != status) {
            log_message(r, status,
                    "Could not write to the certificate temporary file");

            apr_file_close(temp);
            apr_file_remove(tname, r->pool);
            return HTTP_INTERNAL_SERVER_ERROR;
        }
    }
    status = apr_file_close(temp);
    if (APR_SUCCESS != status) {
        log_message(r, status,
                "Could not write to the certificate temporary file");

        apr_file_remove(tname, r->pool);
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* rename the file into place */
    status = apr_file_rename(tname, path, r->pool);
    if (APR_SUCCESS != status) {
        log_message(r, status,
                "Could not rename the certificate temporary file");

        apr_file_remove(tname, r->pool);
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* do we have a link? create it now */
    if (link) {
#if HAVE_APR_FILE_LINK
    	status = apr_file_link(path, link);
#else
        status = APR_ENOTIMPL;
#endif
    	if (APR_SUCCESS != status) {
            log_message(r, status,
                    "Could not link the certificate file to the CADiskCertificateByTransactionPath");

            apr_file_remove(path, r->pool);
            return HTTP_INTERNAL_SERVER_ERROR;
        }
    }

    return OK;
}

static int ca_getcert_disk(request_rec *r, apr_hash_t *search,
        const unsigned char **buffer, apr_size_t *len)
{
    ca_asn1_t *serial;
    ca_asn1_t *transaction_id;
    ca_asn1_t *issuer;
    ca_asn1_t *subject;
    const char *path, *key;
    apr_status_t status = APR_SUCCESS;
    char *fname;
    BIO *in;
    X509 *cert;
    X509_NAME *name;
    PKCS7 *p7;
    X509 *xs, *next;
    const unsigned char *tmp, *end;
    unsigned char *tmp2;
    apr_size_t size;
    STACK_OF(X509) *chain;
    int rv, i;

    ca_config_rec *conf = ap_get_module_config(r->per_dir_config,
            &ca_disk_module);

    /* certificate path defined? */
    if (!conf->serial_path && !conf->transaction_path) {
        return DECLINED;
    }

    /* identify the path and the key, serial takes priority over transaction ID */
    serial = apr_hash_get(search, "serial", APR_HASH_KEY_STRING);
    if (serial && conf->serial_path) {
        BIGNUM *bn = NULL;
        ASN1_INTEGER *i = parse_ASN1_INTEGER(r->pool, serial);
        if (i) {
            bn = ASN1_INTEGER_to_BN(i, NULL);
            if (BN_is_zero(bn)) {
                key = apr_pstrcat(r->pool, "00.", conf->serial_path_suffix,
                        NULL);
            }
            else {
                char *tmp = BN_bn2hex(bn);
                key = apr_pstrcat(r->pool, tmp, ".", conf->serial_path_suffix,
                        NULL);
                OPENSSL_free(tmp);
            }
            path = conf->serial_path;
            BN_free(bn);
        }
        else {
            log_message(r, status, "The serial number could not be parsed");

            return HTTP_BAD_REQUEST;
        }
    }
    else {
        transaction_id = apr_hash_get(search, "transactionID",
                APR_HASH_KEY_STRING);
        if (transaction_id && conf->transaction_path) {
            ASN1_STRING *s = parse_ASN1_STRING(r->pool, transaction_id);
            if (s) {
                path = conf->transaction_path;
#if HAVE_ASN1_STRING_GET0_DATA
                key = apr_pstrcat(r->pool,
                        apr_pstrndup(r->pool,
                                (const char *) ASN1_STRING_get0_data(s),
                                ASN1_STRING_length(s)), ".",
                        conf->transaction_path_suffix, NULL);
#else
                key = apr_pstrcat(r->pool,
                        apr_pstrndup(r->pool,
                                (const char *) ASN1_STRING_data(s),
                                ASN1_STRING_length(s)), ".",
                        conf->transaction_path_suffix, NULL);
#endif
            }
            else {
                log_message(r, status, "The transactionID could not be parsed");

                return HTTP_BAD_REQUEST;
            }
        }
        else {
            return DECLINED;
        }
    }

    /* does the file exist? */
    status = apr_filepath_merge(&fname, path, safe_filename(r->pool, key),
            APR_FILEPATH_SECUREROOT | APR_FILEPATH_NOTRELATIVE, r->pool);
    if (APR_SUCCESS != status) {
        log_message(r, status, "The certificate was not found");

        return HTTP_NOT_FOUND;
    }

    in = BIO_new(BIO_s_file());
    apr_pool_cleanup_register(r->pool, in, ca_BIO_cleanup,
            apr_pool_cleanup_null);

    if (BIO_read_filename(in, fname) <= 0) {
        log_message(r, status, "The certificate was not found");

        return HTTP_NOT_FOUND;
    }

    cert = PEM_read_bio_X509_AUX(in, NULL, NULL, NULL);
    if (!cert) {
        log_message(r, status, "The certificate could not be parsed");

        return HTTP_NOT_FOUND;
    }

    issuer = apr_hash_get(search, "issuer", APR_HASH_KEY_STRING);
    if (!issuer) {
        log_message(r, status, "The issuer was not specified");

        return HTTP_BAD_REQUEST;
    }
    name = parse_X509_NAME(r->pool, issuer);
    if (X509_NAME_cmp(name, X509_get_issuer_name(cert))) {
        char *buf;
        int len;
        BIO *log = BIO_new(BIO_s_mem());

        BIO_puts(log, "('");
        X509_NAME_print_ex(log, name, 0, XN_FLAG_ONELINE);
        BIO_puts(log, "' != '");
        X509_NAME_print_ex(log, X509_get_issuer_name(cert), 0, XN_FLAG_ONELINE);
        BIO_puts(log, "')");
        len = BIO_ctrl_pending(log);
        buf = apr_palloc(r->pool, len);
        BIO_write(log, buf, len);
        BIO_free(log);

        log_message(r, status,
                apr_psprintf(r->pool,
                        "The certificate did not match the issuer: %.*s", len,
                        buf));

        return HTTP_BAD_REQUEST;
    }

    subject = apr_hash_get(search, "subject", APR_HASH_KEY_STRING);
    if (subject) {
        name = parse_X509_NAME(r->pool, subject);
        if (X509_NAME_cmp(name, X509_get_subject_name(cert))) {
            char *buf;
            int len;
            BIO *log = BIO_new(BIO_s_mem());

            BIO_puts(log, "('");
            X509_NAME_print_ex(log, name, 0, XN_FLAG_ONELINE);
            BIO_puts(log, "' != '");
            X509_NAME_print_ex(log, X509_get_subject_name(cert), 0,
                    XN_FLAG_ONELINE);
            BIO_puts(log, "')");
            len = BIO_ctrl_pending(log);
            buf = apr_palloc(r->pool, len);
            BIO_write(log, buf, len);
            BIO_free(log);

            log_message(r, status,
                    apr_psprintf(r->pool,
                            "The certificate did not match the expected subject: %.*s",
                            len, buf));

            return HTTP_BAD_REQUEST;
        }
    }

    /* create a new PKCS#7 */
    p7 = PKCS7_new();
    if (!p7) {
        log_message(r, APR_SUCCESS, "could not create a PKCS7 response");

        return HTTP_INTERNAL_SERVER_ERROR;
    }
    else {
        apr_pool_cleanup_register(r->pool, p7, ca_PKCS7_cleanup,
                apr_pool_cleanup_null);
    }
    PKCS7_set_type(p7, NID_pkcs7_signed);

    /* workaround to avoid :BAD OBJECT encoding in i2d_PKCS7 - https://github.com/openssl/openssl/issues/8618 */
    p7->d.sign->contents->type=OBJ_nid2obj(NID_pkcs7_data);

    /* add the generated certificate */
    if (!PKCS7_add_certificate(p7, cert)) {
        log_message(r, APR_SUCCESS,
                "could not add the signed certificate to the PKCS7 response");

        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* add the certificate chain */
    rv = ap_run_ca_getchain(r, &tmp, &size, NULL);
    if (rv == DECLINED) {
        log_message(r, APR_SUCCESS,
                "No module configured to get the CA certificate chain (ca_getchain)");

        return HTTP_INTERNAL_SERVER_ERROR;
    }
    if (rv != OK) {
        return rv;
    }

    chain = sk_X509_new_null();

    apr_pool_cleanup_register(r->pool, chain, ca_sk_X509_cleanup,
            apr_pool_cleanup_null);

    end = tmp + size;
    while (tmp < end) {
        X509 *cert = NULL;
        if (!(cert = d2i_X509(NULL, &tmp, end - tmp))) {
            log_message(r, APR_SUCCESS,
                    "could not DER decode the CA certificate");

            return HTTP_BAD_REQUEST;
        }
        sk_X509_push(chain, cert);
    }

    xs = cert;
    i = chain ? sk_X509_num(chain) : 0;
    while (i) {
        next = X509_find_by_subject(chain, X509_get_issuer_name(xs));
        if (next) {
            if (!PKCS7_add_certificate(p7, next)) {
                log_message(r, APR_SUCCESS,
                        "could not add a certificate in the chain to the PKCS7 response");

                return HTTP_INTERNAL_SERVER_ERROR;
            }
            if (!X509_NAME_cmp(X509_get_subject_name(xs),
                    X509_get_issuer_name(xs))) {
                break;
            }
            xs = next;
        }
        else {
            break;
        }
        i--;
    }

    /* write out the certificate */
    *len = i2d_PKCS7(p7, NULL);
    if (*len <= 0) {
        log_message(r, APR_SUCCESS,
                "could not DER encode the certificate");

        return HTTP_INTERNAL_SERVER_ERROR;
    }
    *buffer = tmp2 = apr_palloc(r->pool, *len);

    if (!i2d_PKCS7(p7, &tmp2)) {
        log_message(r, APR_SUCCESS,
                "could not DER encode the PKCS7");

        return HTTP_INTERNAL_SERVER_ERROR;
    }

    return OK;
}

static int ca_makeserial_disk(request_rec *r, apr_hash_t *params,
        const unsigned char **serial, apr_size_t *len)
{
    apr_status_t status;
    apr_file_t *tfile;
    ASN1_INTEGER *ai;
    BIGNUM *bn = NULL;
    TXT_DB *db = NULL;
    ASN1_TIME *tm = NULL;
    X509_NAME *subject = NULL;
    char *serial_file_new;

    ca_config_rec *conf = ap_get_module_config(r->per_dir_config,
            &ca_disk_module);

    /* serial file defined? */
    if (!conf->serial_file) {
        return DECLINED;
    }

    status = apr_global_mutex_lock(ca_disk_mutex);
    if (APR_SUCCESS != status) {
        log_message(r, status,
                "Could not obtain the mutex for serial number index file");

        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* get the not after time and subject, if set */
    tm = parse_ASN1_TIME(r->pool,
            apr_hash_get(params, "notAfter", APR_HASH_KEY_STRING));
    subject = parse_X509_NAME(r->pool,
            apr_hash_get(params, "subject", APR_HASH_KEY_STRING));

    /* must we open the openssl database? */
    if (conf->index_file && tm && subject) {

        BIO *in = BIO_new(BIO_s_file());

        if (BIO_read_filename(in, conf->index_file) <= 0) {
            /* on read error, we create a database */
            BIO_free(in);
            in = BIO_new(BIO_s_mem());
        }
        apr_pool_cleanup_register(r->pool, in, ca_BIO_cleanup,
                apr_pool_cleanup_null);

        db = TXT_DB_read(in, DB_NUMBER);
        if (!db) {
            log_message(r, APR_SUCCESS, "Could not parse the index file");

            apr_global_mutex_unlock(ca_disk_mutex);
            return HTTP_INTERNAL_SERVER_ERROR;
        }
        apr_pool_cleanup_register(r->pool, db, ca_TXT_DB_cleanup,
                apr_pool_cleanup_null);

        if (!TXT_DB_create_index(db, DB_serial, NULL,
                LHASH_HASH_FN(index_serial), LHASH_COMP_FN(index_serial))) {
            log_message(r, APR_SUCCESS,
                    apr_psprintf(r->pool,
                            "Could not hash the index file (%ld,%ld,%ld)",
                            db->error, db->arg1, db->arg2));

            apr_global_mutex_unlock(ca_disk_mutex);
            return HTTP_INTERNAL_SERVER_ERROR;
        }

        if (conf->index_unique
                && !TXT_DB_create_index(db, DB_name, index_name_qual,
                        LHASH_HASH_FN(index_name), LHASH_COMP_FN(index_name))) {
            log_message(r, APR_SUCCESS,
                    apr_psprintf(r->pool,
                            "Could not hash the index file (%ld,%ld,%ld)",
                            db->error, db->arg1, db->arg2));

            apr_global_mutex_unlock(ca_disk_mutex);
            return HTTP_INTERNAL_SERVER_ERROR;
        }

    }

    /* create the new file, at the temporary name */
    serial_file_new = apr_pstrcat(r->pool, conf->serial_file, ".XXXXXX", NULL);
    status = apr_file_mktemp(&tfile, serial_file_new,
            APR_FOPEN_WRITE | APR_FOPEN_EXCL, r->pool);
    if (APR_SUCCESS != status) {
        log_message(r, status, "Could not open the serial number index file");

        apr_global_mutex_unlock(ca_disk_mutex);
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* try open the existing file */
    {
        BIO *in = BIO_new(BIO_s_file());
        apr_pool_cleanup_register(r->pool, in, ca_BIO_cleanup,
                apr_pool_cleanup_null);

        if (BIO_read_filename(in, conf->serial_file) <= 0) {

            /* on read error, we create a serial file */
            bn = BN_new();
            apr_pool_cleanup_register(r->pool, bn, ca_BIGNUM_cleanup,
                    apr_pool_cleanup_null);

        }
        else {
            char buffer[1024];

            ai = ASN1_INTEGER_new();
            if (!ai || !a2i_ASN1_INTEGER(in, ai, buffer, sizeof(buffer))) {
                log_message(r, APR_SUCCESS,
                        "Could not parse the serial number");

                apr_file_close(tfile);
                apr_file_remove(serial_file_new, r->pool);
                apr_global_mutex_unlock(ca_disk_mutex);
                return HTTP_INTERNAL_SERVER_ERROR;
            }
            apr_pool_cleanup_register(r->pool, ai, ca_ASN1_INTEGER_cleanup,
                    apr_pool_cleanup_null);

            bn = ASN1_INTEGER_to_BN(ai, NULL);
            if (!bn) {
                log_message(r, APR_SUCCESS,
                        "Could not convert integer to BIGNUM");

                apr_file_close(tfile);
                apr_file_remove(serial_file_new, r->pool);
                apr_global_mutex_unlock(ca_disk_mutex);
                return HTTP_INTERNAL_SERVER_ERROR;
            }
            apr_pool_cleanup_register(r->pool, bn, ca_BIGNUM_cleanup,
                    apr_pool_cleanup_null);

            /* increment the serial */
            BN_add_word(bn, 1);

        }
    }

    /* now save the serial back again */
    ai = BN_to_ASN1_INTEGER(bn, NULL);
    if (!ai) {
        log_message(r, APR_SUCCESS, "Could not convert BIGNUM to integer");

        apr_file_close(tfile);
        apr_file_remove(serial_file_new, r->pool);
        apr_global_mutex_unlock(ca_disk_mutex);
        return HTTP_INTERNAL_SERVER_ERROR;
    }
    else {
        unsigned char *tmp2;
        char *buf;
        apr_size_t size;
        BIO *out = BIO_new(BIO_s_mem());
        i2a_ASN1_INTEGER(out, ai);
        BIO_puts(out, "\n");
        size = BIO_ctrl_pending(out);
        buf = apr_palloc(r->pool, size);
        BIO_read(out, buf, size);
        BIO_free(out);

        if (db) {
            OPENSSL_STRING *row =
                    (char **) OPENSSL_malloc(sizeof(char *)*(DB_NUMBER+1));
            if (!row) {
                log_message(r, APR_SUCCESS,
                        "Could not allocate new row into index file");

                apr_file_close(tfile);
                apr_file_remove(serial_file_new, r->pool);
                apr_global_mutex_unlock(ca_disk_mutex);
                return HTTP_INTERNAL_SERVER_ERROR;
            }

            row[DB_type] = (char *) OPENSSL_malloc(2);
            row[DB_exp_date] = (char *) OPENSSL_malloc(tm->length+1);
            if (BN_is_zero(bn)) {
                row[DB_serial] = BUF_strdup("00");
            }
            else {
                row[DB_serial] = BN_bn2hex(bn);
            }
            row[DB_rev_date] = NULL;
            row[DB_file] = (char *) OPENSSL_malloc(8);
            row[DB_name] = X509_NAME_oneline(subject, NULL, 0);
            if ((!row[DB_type]) || (!row[DB_exp_date]) || (!row[DB_serial])
                    || (!row[DB_file]) || (!row[DB_name])) {
                log_message(r, APR_SUCCESS,
                        "Could not allocate new row into index file");

                apr_file_close(tfile);
                apr_file_remove(serial_file_new, r->pool);
                apr_global_mutex_unlock(ca_disk_mutex);
                return HTTP_INTERNAL_SERVER_ERROR;
            }

            row[DB_type][0] = 'V';
            row[DB_type][1] = '\0';
            BUF_strlcpy(row[DB_file], "unknown", 8);
            memcpy(row[DB_exp_date], tm->data, tm->length);
            row[DB_exp_date][tm->length] = '\0';

            if (!TXT_DB_insert(db, row)) {
                log_message(r, APR_SUCCESS,
                        db->error == DB_ERROR_INDEX_CLASH ?
                                conf->index_unique ? "Index file clash: serial / subject already used" :
                                        "Index file clash: serial already used"
                                : "Could not insert new row into index file");

                apr_file_close(tfile);
                apr_file_remove(serial_file_new, r->pool);
                apr_global_mutex_unlock(ca_disk_mutex);
                return HTTP_INTERNAL_SERVER_ERROR;
            }
        }

        status = apr_file_write_full(tfile, buf, size, &size);
        if (APR_SUCCESS != status) {
            log_message(r, status,
                    "Could not write the serial number index file");

            apr_file_close(tfile);
            apr_file_remove(serial_file_new, r->pool);
            apr_global_mutex_unlock(ca_disk_mutex);
            return HTTP_INTERNAL_SERVER_ERROR;
        }

        status = apr_file_close(tfile);
        if (APR_SUCCESS != status) {
            log_message(r, status,
                    "Could not close the serial number index file");

            apr_file_remove(serial_file_new, r->pool);
            apr_global_mutex_unlock(ca_disk_mutex);
            return HTTP_INTERNAL_SERVER_ERROR;
        }

        status = apr_file_rename(serial_file_new, conf->serial_file, r->pool);
        if (APR_SUCCESS != status) {
            log_message(r, status,
                    "Could not rename the serial number index file");

            apr_file_remove(serial_file_new, r->pool);
            apr_global_mutex_unlock(ca_disk_mutex);
            return HTTP_INTERNAL_SERVER_ERROR;
        }

        if (conf->index_file) {
            char *tname;
            BIO *out = BIO_new(BIO_s_file());

            tname = apr_pstrcat(r->pool, conf->index_file, ".XXXXXX", NULL);
            if (BIO_write_filename(out, tname) <= 0) {
                log_message(r, APR_SUCCESS, "Index file could not be created");

                BIO_free(out);
                apr_global_mutex_unlock(ca_disk_mutex);
                return HTTP_INTERNAL_SERVER_ERROR;
            }

            if (db && !TXT_DB_write(out, db)) {
                log_message(r, APR_SUCCESS, "Index could not generated");

                BIO_free(out);
                apr_global_mutex_unlock(ca_disk_mutex);
                return HTTP_INTERNAL_SERVER_ERROR;
            }
            BIO_free(out);

            /* rename the file into place */
            status = apr_file_rename(tname, conf->index_file, r->pool);
            if (APR_SUCCESS != status) {
                log_message(r, status,
                        "Could not rename the index temporary file");

                apr_file_remove(tname, r->pool);
                apr_global_mutex_unlock(ca_disk_mutex);
                return HTTP_INTERNAL_SERVER_ERROR;
            }
        }

        /* write out the serial number */
        *len = i2d_ASN1_INTEGER(ai, NULL);
        if (*len <= 0) {
            log_message(r, APR_SUCCESS,
                    "could not DER encode the serial number");

            apr_global_mutex_unlock(ca_disk_mutex);
            return HTTP_INTERNAL_SERVER_ERROR;
        }
        *serial = tmp2 = apr_palloc(r->pool, *len);

        if (!i2d_ASN1_INTEGER(ai, &tmp2)) {
            log_message(r, APR_SUCCESS,
                    "could not DER encode the serial number");

            apr_global_mutex_unlock(ca_disk_mutex);
            return HTTP_INTERNAL_SERVER_ERROR;
        }

        apr_global_mutex_unlock(ca_disk_mutex);
        return OK;
    }
}

static void *create_ca_dir_config(apr_pool_t *p, char *d)
{
    ca_config_rec *conf = apr_pcalloc(p, sizeof(ca_config_rec));

    return conf;
}

static void *merge_ca_dir_config(apr_pool_t *p, void *basev, void *addv)
{
    ca_config_rec *new = (ca_config_rec *) apr_pcalloc(p,
            sizeof(ca_config_rec));
    ca_config_rec *add = (ca_config_rec *) addv;
    ca_config_rec *base = (ca_config_rec *) basev;

    new->csr_path = (add->csr_path_set == 0) ? base->csr_path : add->csr_path;
    new->csr_path_set = add->csr_path_set || base->csr_path_set;
    new->serial_path =
            (add->serial_path_set == 0) ? base->serial_path : add->serial_path;
    new->serial_path_suffix =
            (add->serial_path_set == 0) ? base->serial_path_suffix :
                    add->serial_path_suffix;
    new->serial_path_set = add->serial_path_set || base->serial_path_set;
    new->transaction_path =
            (add->transaction_path_set == 0) ? base->transaction_path :
                    add->transaction_path;
    new->transaction_path_suffix =
            (add->transaction_path_set == 0) ? base->transaction_path_suffix :
                    add->transaction_path_suffix;
    new->transaction_path_set = add->transaction_path_set
            || base->transaction_path_set;
    new->serial_file =
            (add->serial_file_set == 0) ? base->serial_file : add->serial_file;
    new->serial_file_set = add->serial_file_set || base->serial_file_set;
    new->index_file =
            (add->index_file_set == 0) ? base->index_file : add->index_file;
    new->index_file_set = add->index_file_set || base->index_file_set;
    new->index_unique =
            (add->index_unique_set == 0) ? base->index_unique :
                    add->index_unique;
    new->index_unique_set = add->index_unique_set || base->index_unique_set;

    return new;
}

static const char *set_csr_path(cmd_parms *cmd, void *dconf, const char *arg)
{
    ca_config_rec *conf = dconf;

    arg = ap_server_root_relative(cmd->pool, arg);

    conf->csr_path = arg;
    conf->csr_path_set = 1;

    return NULL;
}

static const char *set_serial_path(cmd_parms *cmd, void *dconf,
        const char *path, const char *suffix)
{
    ca_config_rec *conf = dconf;

    path = ap_server_root_relative(cmd->pool, path);

    conf->serial_path = path;
    conf->serial_path_suffix = suffix ? suffix : DEFAULT_SERIAL_SUFFIX;
    conf->serial_path_set = 1;

    return NULL;
}

static const char *set_transaction_path(cmd_parms *cmd, void *dconf,
        const char *path, const char *suffix)
{
    ca_config_rec *conf = dconf;

    path = ap_server_root_relative(cmd->pool, path);

    conf->transaction_path = path;
    conf->transaction_path_suffix = suffix ? suffix : DEFAULT_TRANSACTION_SUFFIX;
    conf->transaction_path_set = 1;

    return NULL;
}

static const char *set_serial_file(cmd_parms *cmd, void *dconf, const char *arg)
{
    ca_config_rec *conf = dconf;

    arg = ap_server_root_relative(cmd->pool, arg);

    conf->serial_file = arg;
    conf->serial_file_set = 1;

    return NULL;
}

static const char *set_index_file(cmd_parms *cmd, void *dconf, const char *arg)
{
    ca_config_rec *conf = dconf;

    arg = ap_server_root_relative(cmd->pool, arg);

    conf->index_file = arg;
    conf->index_file_set = 1;

    return NULL;
}

static const char *set_index_unique(cmd_parms *cmd, void *dconf, int flag)
{
    ca_config_rec *conf = dconf;

    conf->index_unique = flag;
    conf->index_unique_set = 1;

    return NULL;
}

static const command_rec ca_cmds[] =
        {
                        AP_INIT_TAKE1("CADiskCertificateSignRequestPath",
                                set_csr_path, NULL, RSRC_CONF | ACCESS_CONF,
                                "Set to the path where certificate sign requests should be stored."),
                        AP_INIT_TAKE12("CADiskCertificateByTransactionPath",
                                set_transaction_path, NULL, RSRC_CONF | ACCESS_CONF,
                                "Set to the path for certificates keyed by transaction, followed by optional suffix (defaults to 'cert')."),
                        AP_INIT_TAKE12("CADiskCertificateBySerialPath",
                                set_serial_path, NULL, RSRC_CONF | ACCESS_CONF,
                                "Set to the path for certificates keyed by serial number, followed by optional suffix (defaults to 'pem')."),
                        AP_INIT_TAKE1("CADiskSerialFile",
                                set_serial_file, NULL, RSRC_CONF | ACCESS_CONF,
                                "Set to the name of the serial file, if any."),
                        AP_INIT_TAKE1("CADiskIndexFile",
                                set_index_file, NULL, RSRC_CONF | ACCESS_CONF,
                                "Set to the name of the index file, if any."),
                AP_INIT_FLAG("CADiskIndexUnique",
                        set_index_unique, NULL, RSRC_CONF | ACCESS_CONF,
                        "If enabled, the certificate subject must be unique."),
                { NULL } };

static apr_status_t ca_cleanup(void *data)
{
    ERR_free_strings();
    EVP_cleanup();
    return APR_SUCCESS;
}

static int ca_pre_disk_config(apr_pool_t *pconf, apr_pool_t *plog,
        apr_pool_t *ptemp)
{
    ap_mutex_register(pconf, ca_disk_mutex_type, NULL, APR_LOCK_DEFAULT, 0);

    OpenSSL_add_all_algorithms();
    ERR_load_crypto_strings();

    apr_pool_cleanup_register(pconf, NULL, ca_cleanup, apr_pool_cleanup_null);

    /* define the new object definitions needed for SCEP            */
    int i;
    for (i = 0; i < NEW_NIDS; i++) {
        if (scep_oid_def[i].nid == -1) {
            scep_oid_def[i].nid = OBJ_create(scep_oid_def[i].oid,
                    scep_oid_def[i].name1, scep_oid_def[i].name2);
        }
    }

    return APR_SUCCESS;
}

static int ca_disk_post_config(apr_pool_t *pconf, apr_pool_t *plog,
        apr_pool_t *ptemp, server_rec *s)
{
    apr_status_t rs;

    /* if the mutex already exists, as it would after a restart, reuse */
    if (ca_disk_mutex) {
        return OK;
    }

    /* Create global mutex */
    rs = ap_global_mutex_create(&ca_disk_mutex, NULL, ca_disk_mutex_type, NULL,
            s, pconf, 0);
    if (APR_SUCCESS != rs) {
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    return OK;
}

/*
 * This routine gets called when a child inits. We use it to attach
 * to the shared memory segment, and reinitialize the mutex.
 */

static void ca_disk_child_init(apr_pool_t *p, server_rec *s)
{
    apr_status_t rs;

    /*
     * Re-open the mutex for the child. Note we're reusing
     * the mutex pointer global here.
     */
    rs = apr_global_mutex_child_init(&ca_disk_mutex,
            apr_global_mutex_lockfile(ca_disk_mutex), p);
    if (APR_SUCCESS != rs) {
        ap_log_error(
                APLOG_MARK, APLOG_CRIT, rs, s, "Failed to reopen mutex %s in child", ca_disk_mutex_type);
        /* There's really nothing else we can do here, since This
         * routine doesn't return a status. If this ever goes wrong,
         * it will turn Apache into a fork bomb. Let's hope it never
         * will.
         */
        exit(1); /* Ugly, but what else? */
    }
}

static void register_hooks(apr_pool_t *p)
{
    ap_hook_pre_config(ca_pre_disk_config, NULL, NULL, APR_HOOK_MIDDLE);
    ap_hook_child_init(ca_disk_child_init, NULL, NULL, APR_HOOK_MIDDLE);
    ap_hook_post_config(ca_disk_post_config, NULL, NULL, APR_HOOK_MIDDLE);

    ap_hook_ca_sign(ca_sign_disk, NULL, NULL, APR_HOOK_MIDDLE);
    ap_hook_ca_certstore(ca_certstore_disk, NULL, NULL, APR_HOOK_MIDDLE);
    ap_hook_ca_getcert(ca_getcert_disk, NULL, NULL, APR_HOOK_MIDDLE);
    ap_hook_ca_makeserial(ca_makeserial_disk, NULL, NULL,
            APR_HOOK_MIDDLE);

}

AP_DECLARE_MODULE(ca_disk) =
{
    STANDARD20_MODULE_STUFF,
    create_ca_dir_config, /* dir config creater */
    merge_ca_dir_config,  /* dir merger --- default is to override */
    NULL,                 /* server config */
    NULL,                 /* merge server config */
    ca_cmds,              /* command apr_table_t */
    register_hooks        /* register hooks */
};