dlz/drivers/dlz_mysql_driver.c

	dlz_mysql_driver.c revision abff0f462a758383d012887d3a97da4dac0c5a94
/*
 * Copyright (C) 2002 Stichting NLnet, Netherlands, stichting@nlnet.nl.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the
 * above copyright notice and this permission notice appear in all
 * copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND STICHTING NLNET
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * STICHTING NLNET BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
 * USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * The development of Dynamically Loadable Zones (DLZ) for Bind 9 was
 * conceived and contributed by Rob Butler.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the
 * above copyright notice and this permission notice appear in all
 * copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ROB BUTLER
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * ROB BUTLER BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
 * USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * Copyright (C) 1999-2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifdef DLZ_MYSQL

#include <config.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <dns/log.h>
#include <dns/sdlz.h>
#include <dns/result.h>

#include <isc/mem.h>
#include <isc/platform.h>
#include <isc/print.h>
#include <isc/result.h>
#include <isc/string.h>
#include <isc/util.h>

#include <named/globals.h>

#include <dlz/sdlz_helper.h>
#include <dlz/dlz_mysql_driver.h>

#include <mysql.h>

static dns_sdlzimplementation_t *dlz_mysql = NULL;

#define dbc_search_limit 30
#define ALLNODES 1
#define ALLOWXFR 2
#define AUTHORITY 3
#define FINDZONE 4
#define COUNTZONE 5
#define LOOKUP 6

#define safeGet(in) in == NULL ? "" : in

/*
 * Private methods
 */

/*%
 * Allocates memory for a new string, and then constructs the new
 * string by "escaping" the input string.  The new string is
 * safe to be used in queries.  This is necessary because we cannot
 * be sure of what types of strings are passed to us, and we don't
 * want special characters in the string causing problems.
 */

static char *
mysqldrv_escape_string(MYSQL *mysql, const char *instr) {

    char *outstr;
    unsigned int len;

    if (instr == NULL)
        return NULL;

    len = strlen(instr);

    outstr = isc_mem_allocate(ns_g_mctx ,(2 * len * sizeof(char)) + 1);
    if (outstr == NULL)
        return NULL;

    mysql_real_escape_string(mysql, outstr, instr, len);

    return outstr;
}

/*%
 * This function is the real core of the driver.   Zone, record
 * and client strings are passed in (or NULL is passed if the
 * string is not available).  The type of query we want to run
 * is indicated by the query flag, and the dbdata object is passed
 * passed in to.  dbdata really holds a single database instance.
 * The function will construct and run the query, hopefully getting
 * a result set.
 */

static isc_result_t
mysql_get_resultset(const char *zone, const char *record,
            const char *client, unsigned int query,
            void *dbdata, MYSQL_RES **rs)
{
    isc_result_t result;
    dbinstance_t *dbi = NULL;
    char *querystring = NULL;
    unsigned int i = 0;
    unsigned int j = 0;
    int qres = 0;

    if (query != COUNTZONE)
        REQUIRE(*rs == NULL);
    else
        REQUIRE(rs == NULL);

    /* get db instance / connection */
    dbi =  (dbinstance_t *) dbdata;

    /* if DBI is null, can't do anything else */
    if (dbi == NULL) {
        result = ISC_R_FAILURE;
        goto cleanup;
    }

    /* what type of query are we going to run? */
    switch(query) {
    case ALLNODES:
        /*
         * if the query was not passed in from the config file
         * then we can't run it.  return not_implemented, so
         * it's like the code for that operation was never
         * built into the driver.... AHHH flexibility!!!
         */
        if (dbi->allnodes_q == NULL) {
            result = ISC_R_NOTIMPLEMENTED;
            goto cleanup;
        }
        break;
    case ALLOWXFR:
        /* same as comments as ALLNODES */
        if (dbi->allowxfr_q == NULL) {
            result = ISC_R_NOTIMPLEMENTED;
            goto cleanup;
        }
        break;
    case AUTHORITY:
        /* same as comments as ALLNODES */
        if (dbi->authority_q == NULL) {
            result = ISC_R_NOTIMPLEMENTED;
            goto cleanup;
        }
        break;
    case FINDZONE:
        /* this is required.  It's the whole point of DLZ! */
        if (dbi->findzone_q == NULL) {
            isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
                      "No query specified for findzone.  "
                      "Findzone requires a query");
            result = ISC_R_FAILURE;
            goto cleanup;
        }
        break;
    case COUNTZONE:
        /* same as comments as ALLNODES */
        if (dbi->countzone_q == NULL) {
            result = ISC_R_NOTIMPLEMENTED;
            goto cleanup;
        }
        break;
    case LOOKUP:
        /* this is required.  It's also a major point of DLZ! */
        if (dbi->lookup_q == NULL) {
            isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
                      "No query specified for lookup.  "
                      "Lookup requires a query");
            result = ISC_R_FAILURE;
            goto cleanup;
        }
        break;
    default:
        /*
         * this should never happen.  If it does, the code is
         * screwed up!
         */
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "Incorrect query flag passed to "
                 "mysql_get_resultset");
        result = ISC_R_UNEXPECTED;
        goto cleanup;
    }


    /*
     * was a zone string passed?  If so, make it safe for use in
     * queries.
     */
    if (zone != NULL) {
        dbi->zone = mysqldrv_escape_string((MYSQL *) dbi->dbconn,
                           zone);
        if (dbi->zone == NULL) {
            result = ISC_R_NOMEMORY;
            goto cleanup;
        }
    } else {    /* no string passed, set the string pointer to NULL */
        dbi->zone = NULL;
    }

    /*
     * was a record string passed?  If so, make it safe for use in
     * queries.
     */
    if (record != NULL) {
        dbi->record = mysqldrv_escape_string((MYSQL *) dbi->dbconn,
                             record);
        if (dbi->record == NULL) {
            result = ISC_R_NOMEMORY;
            goto cleanup;
        }
    } else {    /* no string passed, set the string pointer to NULL */
        dbi->record = NULL;
    }

    /*
     * was a client string passed?  If so, make it safe for use in
     * queries.
     */
    if (client != NULL) {
        dbi->client = mysqldrv_escape_string((MYSQL *) dbi->dbconn,
                             client);
        if (dbi->client == NULL) {
            result = ISC_R_NOMEMORY;
            goto cleanup;
        }
    } else {    /* no string passed, set the string pointer to NULL */
        dbi->client = NULL;
    }

    /*
     * what type of query are we going to run?  this time we build
     * the actual query to run.
     */
    switch(query) {
    case ALLNODES:
        querystring = build_querystring(ns_g_mctx, dbi->allnodes_q);
        break;
    case ALLOWXFR:
        querystring = build_querystring(ns_g_mctx, dbi->allowxfr_q);
        break;
    case AUTHORITY:
        querystring = build_querystring(ns_g_mctx, dbi->authority_q);
        break;
    case FINDZONE:
        querystring = build_querystring(ns_g_mctx, dbi->findzone_q);
        break;
    case COUNTZONE:
        querystring = build_querystring(ns_g_mctx, dbi->countzone_q);
        break;
    case LOOKUP:
        querystring = build_querystring(ns_g_mctx, dbi->lookup_q);
        break;
    default:
        /*
         * this should never happen.  If it does, the code is
         * screwed up!
         */
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "Incorrect query flag passed to "
                 "mysql_get_resultset");
        result = ISC_R_UNEXPECTED;
        goto cleanup;
    }

    /* if the querystring is null, Bummer, outta RAM.  UPGRADE TIME!!!   */
    if (querystring == NULL) {
        result = ISC_R_NOMEMORY;
        goto cleanup;
    }

    /*
     * output the full query string during debug so we can see
     * what lame error the query has.
     */
    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
              DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(1),
              "\nQuery String: %s\n", querystring);

    /* attempt query up to 3 times. */
    for (i=0; i < 3; i++) {
        qres = mysql_query((MYSQL *) dbi->dbconn, querystring);
        if (qres == 0)
            break;
        for (j=0; mysql_ping((MYSQL *) dbi->dbconn) != 0 && j < 4; j++)
            ;
    }

    if (qres == 0) {
        result = ISC_R_SUCCESS;
        if (query != COUNTZONE) {
            *rs = mysql_store_result((MYSQL *) dbi->dbconn);
            if (*rs == NULL)
                result = ISC_R_FAILURE;
        }
    } else {
        result = ISC_R_FAILURE;
    }


 cleanup:
    /* it's always good to cleanup after yourself */

    /* if we couldn't even get DBI, just return NULL */
    if (dbi == NULL)
        return ISC_R_FAILURE;

    /* free dbi->zone string */
    if (dbi->zone != NULL)
        isc_mem_free(ns_g_mctx, dbi->zone);

    /* free dbi->record string */
    if (dbi->record != NULL)
        isc_mem_free(ns_g_mctx, dbi->record);

    /* free dbi->client string */
    if (dbi->client != NULL)
        isc_mem_free(ns_g_mctx, dbi->client);

    /* release query string */
    if (querystring  != NULL)
        isc_mem_free(ns_g_mctx, querystring);

    /* return result */
    return result;
}

/*%
 * The processing of result sets for lookup and authority are
 * exactly the same.  So that functionality has been moved
 * into this function to minimize code.
 */

static isc_result_t
mysql_process_rs(dns_sdlzlookup_t *lookup, MYSQL_RES *rs)
{
    isc_result_t result = ISC_R_NOTFOUND;
    MYSQL_ROW row;
    unsigned int fields;
    unsigned int j;
    unsigned int len;
    char *tmpString;
    char *endp;
    int ttl;

    row = mysql_fetch_row(rs);  /* get a row from the result set */
    fields = mysql_num_fields(rs);  /* how many columns in result set */
    while (row != NULL) {
        switch(fields) {
        case 1:
            /*
             * one column in rs, it's the data field.  use
             * default type of A record, and default TTL
             * of 86400
             */
            result = dns_sdlz_putrr(lookup, "a", 86400,
                        safeGet(row[0]));
            break;
        case 2:
            /*
             * two columns, data field, and data type.
             * use default TTL of 86400.
             */
            result = dns_sdlz_putrr(lookup, safeGet(row[0]), 86400,
                        safeGet(row[1]));
            break;
        case 3:
            /*
             * three columns, all data no defaults.
             * convert text to int, make sure it worked
             * right.
             */
            ttl = strtol(safeGet(row[0]), &endp, 10);
            if (*endp != '\0' || ttl < 0) {
                isc_log_write(dns_lctx,
                          DNS_LOGCATEGORY_DATABASE,
                          DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                          "mysql driver ttl must be "
                          "a postive number");
            }
            result = dns_sdlz_putrr(lookup, safeGet(row[1]), ttl,
                        safeGet(row[2]));
            break;
        default:
            /*
             * more than 3 fields, concatenate the last
             * ones together.  figure out how long to make
             * string.
             */
            for (j=2, len=0; j < fields; j++) {
                len += strlen(safeGet(row[j])) + 1;
            }
            /*
             * allocate string memory, allow for NULL to
             * term string
             */
            tmpString = isc_mem_allocate(ns_g_mctx, len + 1);
            if (tmpString == NULL) {
                /* major bummer, need more ram */
                isc_log_write(dns_lctx,
                          DNS_LOGCATEGORY_DATABASE,
                          DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                          "mysql driver unable "
                          "to allocate memory for "
                          "temporary string");
                mysql_free_result(rs);
                return (ISC_R_FAILURE); /* Yeah, I'd say! */
            }
            /* copy field to tmpString */
            strcpy(tmpString, safeGet(row[2]));


            /*
             * concat the rest of fields together, space
             * between each one.
             */
            for (j=3; j < fields; j++) {
                strcat(tmpString, " ");
                strcat(tmpString, safeGet(row[j]));
            }
            /* convert text to int, make sure it worked right */
            ttl = strtol(safeGet(row[0]), &endp, 10);
            if (*endp != '\0' || ttl < 0) {
                isc_log_write(dns_lctx,
                          DNS_LOGCATEGORY_DATABASE,
                          DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                          "mysql driver ttl must be "
                          "a postive number");
            }
            /* ok, now tell Bind about it. */
            result = dns_sdlz_putrr(lookup, safeGet(row[1]),
                        ttl, tmpString);
            /* done, get rid of this thing. */
            isc_mem_free(ns_g_mctx, tmpString);
        }
        /* I sure hope we were successful */
        if (result != ISC_R_SUCCESS) {
            /* nope, get rid of the Result set, and log a msg */
            mysql_free_result(rs);
            isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                      "dns_sdlz_putrr returned error. "
                      "Error code was: %s",
                      isc_result_totext(result));
            return (ISC_R_FAILURE);
        }
        row = mysql_fetch_row(rs);  /* get next row */
    }

    /* free result set memory */
    mysql_free_result(rs);

    /* return result code */
    return result;
}

/*
 * SDLZ interface methods
 */

/*% determine if the zone is supported by (in) the database */

static isc_result_t
mysql_findzone(void *driverarg, void *dbdata, const char *name,
           dns_clientinfomethods_t *methods, dns_clientinfo_t *clientinfo)
{
    isc_result_t result;
    MYSQL_RES *rs = NULL;
    my_ulonglong rows;

    UNUSED(driverarg);
    UNUSED(methods);
    UNUSED(clientinfo);

    /* run the query and get the result set from the database. */
    result = mysql_get_resultset(name, NULL, NULL, FINDZONE, dbdata, &rs);
    /* if we didn't get a result set, log an err msg. */
    if (result != ISC_R_SUCCESS || rs == NULL) {
        if (rs != NULL)
            mysql_free_result(rs);
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver unable to return "
                  "result set for findzone query");
        return (ISC_R_FAILURE);
    }
    /* count how many rows in result set */
    rows = mysql_num_rows(rs);
    /* get rid of result set, we are done with it. */
    mysql_free_result(rs);

    /* if we returned any rows, zone is supported. */
    if (rows > 0) {
        mysql_get_resultset(name, NULL, NULL, COUNTZONE, dbdata, NULL);
        return (ISC_R_SUCCESS);
    }

    /* no rows returned, zone is not supported. */
    return (ISC_R_NOTFOUND);
}

/*% Determine if the client is allowed to perform a zone transfer */
static isc_result_t
mysql_allowzonexfr(void *driverarg, void *dbdata, const char *name,
           const char *client)
{
    isc_result_t result;
    MYSQL_RES *rs = NULL;
    my_ulonglong rows;

    UNUSED(driverarg);

    /* first check if the zone is supported by the database. */
    result = mysql_findzone(driverarg, dbdata, name, NULL, NULL);
    if (result != ISC_R_SUCCESS)
        return (ISC_R_NOTFOUND);

    /*
     * if we get to this point we know the zone is supported by
     * the database the only questions now are is the zone
     * transfer is allowed for this client and did the config file
     * have an allow zone xfr query.
     *
     * Run our query, and get a result set from the database.
     */
    result = mysql_get_resultset(name, NULL, client, ALLOWXFR,
                     dbdata, &rs);
    /* if we get "not implemented", send it along. */
    if (result == ISC_R_NOTIMPLEMENTED)
        return result;
    /* if we didn't get a result set, log an err msg. */
    if (result != ISC_R_SUCCESS || rs == NULL) {
        if (rs != NULL)
            mysql_free_result(rs);
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver unable to return "
                  "result set for allow xfr query");
        return (ISC_R_FAILURE);
    }
    /* count how many rows in result set */
    rows = mysql_num_rows(rs);
    /* get rid of result set, we are done with it. */
    mysql_free_result(rs);

    /* if we returned any rows, zone xfr is allowed. */
    if (rows > 0)
        return (ISC_R_SUCCESS);

    /* no rows returned, zone xfr not allowed */
    return (ISC_R_NOPERM);
}

/*%
 * If the client is allowed to perform a zone transfer, the next order of
 * business is to get all the nodes in the zone, so bind can respond to the
 * query.
 */
static isc_result_t
mysql_allnodes(const char *zone, void *driverarg, void *dbdata,
           dns_sdlzallnodes_t *allnodes)
{
    isc_result_t result;
    MYSQL_RES *rs = NULL;
    MYSQL_ROW row;
    unsigned int fields;
    unsigned int j;
    unsigned int len;
    char *tmpString;
    char *endp;
    int ttl;

    UNUSED(driverarg);

    /* run the query and get the result set from the database. */
    result = mysql_get_resultset(zone, NULL, NULL, ALLNODES, dbdata, &rs);
    /* if we get "not implemented", send it along */
    if (result == ISC_R_NOTIMPLEMENTED)
        return result;
    /* if we didn't get a result set, log an err msg. */
    if (result != ISC_R_SUCCESS) {
        if (rs != NULL)
            mysql_free_result(rs);
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver unable to return "
                  "result set for all nodes query");
        return (ISC_R_FAILURE);
    }

    result = ISC_R_NOTFOUND;

    row = mysql_fetch_row(rs);  /* get a row from the result set */
    fields = mysql_num_fields(rs);  /* how many columns in result set */
    while (row != NULL) {
        if (fields < 4) {   /* gotta have at least 4 columns */
            isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                      "mysql driver too few fields returned "
                      "by all nodes query");
        }
        /* convert text to int, make sure it worked right  */
        ttl = strtol(safeGet(row[0]), &endp, 10);
        if (*endp != '\0' || ttl < 0) {
            isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                      "mysql driver ttl must be "
                      "a postive number");
        }
        if (fields == 4) {
            /* tell Bind about it. */
            result = dns_sdlz_putnamedrr(allnodes, safeGet(row[2]),
                             safeGet(row[1]), ttl,
                             safeGet(row[3]));
        } else {
            /*
             * more than 4 fields, concatenate the last
             * ones together.  figure out how long to make
             * string.
             */
            for (j=3, len=0; j < fields; j++) {
                len += strlen(safeGet(row[j])) + 1;
            }
            /* allocate memory, allow for NULL to term string */
            tmpString = isc_mem_allocate(ns_g_mctx, len + 1);
            if (tmpString == NULL) {    /* we need more ram. */
                isc_log_write(dns_lctx,
                          DNS_LOGCATEGORY_DATABASE,
                          DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                          "mysql driver unable "
                          "to allocate memory for "
                          "temporary string");
                mysql_free_result(rs);
                return (ISC_R_FAILURE);
            }
            /* copy this field to tmpString */
            strcpy(tmpString, safeGet(row[3]));
            /* concatonate the rest, with spaces between */
            for (j=4; j < fields; j++) {
                strcat(tmpString, " ");
                strcat(tmpString, safeGet(row[j]));
            }
            /* tell Bind about it. */
            result = dns_sdlz_putnamedrr(allnodes, safeGet(row[2]),
                             safeGet(row[1]),
                             ttl, tmpString);
            isc_mem_free(ns_g_mctx, tmpString);
        }
        /* if we weren't successful, log err msg */
        if (result != ISC_R_SUCCESS) {
            isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                      "dns_sdlz_putnamedrr returned error. "
                      "Error code was: %s",
                      isc_result_totext(result));
            result = ISC_R_FAILURE;
            break;
        }
        /* get next row from the result set */
        row = mysql_fetch_row(rs);
    }

    /* free result set memory */
    mysql_free_result(rs);

    return result;
}

/*% if the lookup function does not return SOA or NS records for the zone,
 * use this function to get that information for Bind.
 */

static isc_result_t
mysql_authority(const char *zone, void *driverarg, void *dbdata,
        dns_sdlzlookup_t *lookup)
{
    isc_result_t result;
    MYSQL_RES *rs = NULL;

    UNUSED(driverarg);

    /* run the query and get the result set from the database. */
    result = mysql_get_resultset(zone, NULL, NULL, AUTHORITY, dbdata, &rs);
    /* if we get "not implemented", send it along */
    if (result == ISC_R_NOTIMPLEMENTED)
        return result;
    /* if we didn't get a result set, log an err msg. */
    if (result != ISC_R_SUCCESS) {
        if (rs != NULL)
            mysql_free_result(rs);
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver unable to return "
                  "result set for authority query");
        return (ISC_R_FAILURE);
    }
    /*
     * lookup and authority result sets are processed in the same
     * manner mysql_process_rs does the job for both functions.
     */
    return mysql_process_rs(lookup, rs);
}

/*% if zone is supported, lookup up a (or multiple) record(s) in it */
static isc_result_t
mysql_lookup(const char *zone, const char *name, void *driverarg,
         void *dbdata, dns_sdlzlookup_t *lookup,
         dns_clientinfomethods_t *methods, dns_clientinfo_t *clientinfo)
{
    isc_result_t result;
    MYSQL_RES *rs = NULL;

    UNUSED(driverarg);
    UNUSED(methods);
    UNUSED(clientinfo);

    /* run the query and get the result set from the database. */
    result = mysql_get_resultset(zone, name, NULL, LOOKUP, dbdata, &rs);
    /* if we didn't get a result set, log an err msg. */
    if (result != ISC_R_SUCCESS) {
        if (rs != NULL)
            mysql_free_result(rs);
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver unable to return "
                  "result set for lookup query");
        return (ISC_R_FAILURE);
    }
    /*
     * lookup and authority result sets are processed in the same manner
     * mysql_process_rs does the job for both functions.
     */
    return mysql_process_rs(lookup, rs);
}

/*%
 * create an instance of the driver.  Remember, only 1 copy of the driver's
 * code is ever loaded, the driver has to remember which context it's
 * operating in.  This is done via use of the dbdata argument which is
 * passed into all query functions.
 */
static isc_result_t
mysql_create(const char *dlzname, unsigned int argc, char *argv[],
         void *driverarg, void **dbdata)
{
    isc_result_t result;
    dbinstance_t *dbi = NULL;
    char *tmp = NULL;
    char *dbname = NULL;
    char *host = NULL;
    char *user = NULL;
    char *pass = NULL;
    char *socket = NULL;
    int port;
    MYSQL *dbc;
    char *endp;
    int j;
    unsigned int flags = 0;
#if MYSQL_VERSION_ID >= 50000
        my_bool auto_reconnect = 1;
#endif

    UNUSED(driverarg);
    UNUSED(dlzname);

    /* verify we have at least 4 arg's passed to the driver */
    if (argc < 4) {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver requires "
                  "at least 4 command line args.");
        return (ISC_R_FAILURE);
    }

    /* no more than 8 arg's should be passed to the driver */
    if (argc > 8) {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver cannot accept "
                  "more than 7 command line args.");
        return (ISC_R_FAILURE);
    }

    /* parse connection string and get paramters. */

    /* get db name - required */
    dbname = getParameterValue(argv[1], "dbname=");
    if (dbname == NULL) {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver requires a dbname parameter.");
        result = ISC_R_FAILURE;
        goto full_cleanup;
    }

    /* get db port.  Not required, but must be > 0 if specified */
    tmp = getParameterValue(argv[1], "port=");
    if (tmp == NULL) {
        port = 0;
    } else {
        port = strtol(tmp, &endp, 10);
        if (*endp != '\0' || port < 0) {
            isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                      "Mysql driver port "
                      "must be a positive number.");
            isc_mem_free(ns_g_mctx, tmp);
            result = ISC_R_FAILURE;
            goto full_cleanup;
        }
        isc_mem_free(ns_g_mctx, tmp);
    }

    /* how many queries were passed in from config file? */
    switch(argc) {
    case 4:
        result = build_sqldbinstance(ns_g_mctx, NULL, NULL, NULL,
                         argv[2], argv[3], NULL, &dbi);
        break;
    case 5:
        result = build_sqldbinstance(ns_g_mctx, NULL, NULL, argv[4],
                         argv[2], argv[3], NULL, &dbi);
        break;
    case 6:
        result = build_sqldbinstance(ns_g_mctx, argv[5], NULL, argv[4],
                         argv[2], argv[3], NULL, &dbi);
        break;
    case 7:
        result = build_sqldbinstance(ns_g_mctx, argv[5],
                         argv[6], argv[4],
                         argv[2], argv[3], NULL, &dbi);
        break;
    case 8:
        result = build_sqldbinstance(ns_g_mctx, argv[5],
                         argv[6], argv[4],
                         argv[2], argv[3], argv[7], &dbi);
        break;
    default:
        /* not really needed, should shut up compiler. */
        result = ISC_R_FAILURE;
    }

    /* unsuccessful?, log err msg and cleanup. */
    if (result != ISC_R_SUCCESS) {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver could not create "
                  "database instance object.");
        result = ISC_R_FAILURE;
        goto cleanup;
    }

    /* create and set db connection */
    dbi->dbconn = mysql_init(NULL);

    /* if db connection cannot be created, log err msg and cleanup. */
    if (dbi->dbconn == NULL) {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver could not allocate "
                  "memory for database connection");
        result = ISC_R_FAILURE;
        goto full_cleanup;
    }

    tmp = getParameterValue(argv[1], "compress=");
    if (tmp != NULL) {
        if (strcasecmp(tmp, "true") == 0)
            flags = CLIENT_COMPRESS;
        isc_mem_free(ns_g_mctx, tmp);
    }

    tmp = getParameterValue(argv[1], "ssl=");
    if (tmp != NULL) {
        if (strcasecmp(tmp, "true") == 0)
            flags = flags | CLIENT_SSL;
        isc_mem_free(ns_g_mctx, tmp);
    }

    tmp = getParameterValue(argv[1], "space=");
    if (tmp != NULL) {
        if (strcasecmp(tmp, "ignore") == 0)
            flags = flags | CLIENT_IGNORE_SPACE;
        isc_mem_free(ns_g_mctx, tmp);
    }

    dbc = NULL;
    host = getParameterValue(argv[1], "host=");
    user = getParameterValue(argv[1], "user=");
    pass = getParameterValue(argv[1], "pass=");
    socket = getParameterValue(argv[1], "socket=");

#if MYSQL_VERSION_ID >= 50000
    /* enable automatic reconnection. */
        if (mysql_options((MYSQL *) dbi->dbconn, MYSQL_OPT_RECONNECT,
              &auto_reconnect) != 0) {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_WARNING,
                  "mysql driver failed to set "
                  "MYSQL_OPT_RECONNECT option, continuing");
    }
#endif

    for (j=0; dbc == NULL && j < 4; j++)
        dbc = mysql_real_connect((MYSQL *) dbi->dbconn, host,
                     user, pass, dbname, port, socket,
                     flags);

    /* let user know if we couldn't connect. */
    if (dbc == NULL) {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "mysql driver failed to create "
                  "database connection after 4 attempts");
        result = ISC_R_FAILURE;
        goto full_cleanup;
    }

    /* return db connection via dbdata */
    *dbdata = dbi;

    result = ISC_R_SUCCESS;
    goto cleanup;

 full_cleanup:

    if (dbi != NULL)
        destroy_sqldbinstance(dbi);

 cleanup:

    if (dbname != NULL)
        isc_mem_free(ns_g_mctx, dbname);
    if (host != NULL)
        isc_mem_free(ns_g_mctx, host);
    if (user != NULL)
        isc_mem_free(ns_g_mctx, user);
    if (pass != NULL)
        isc_mem_free(ns_g_mctx, pass);
    if (socket != NULL)
        isc_mem_free(ns_g_mctx, socket);


    return result;
}

/*%
 * destroy the driver.  Remember, only 1 copy of the driver's
 * code is ever loaded, the driver has to remember which context it's
 * operating in.  This is done via use of the dbdata argument.
 * so we really only need to clean it up since we are not using driverarg.
 */

static void
mysql_destroy(void *driverarg, void *dbdata)
{
    dbinstance_t *dbi;

    UNUSED(driverarg);

    dbi = (dbinstance_t *) dbdata;

    /* release DB connection */
    if (dbi->dbconn != NULL)
        mysql_close((MYSQL *) dbi->dbconn);

    /* destroy DB instance */
    destroy_sqldbinstance(dbi);
}

/* pointers to all our runtime methods. */
/* this is used during driver registration */
/* i.e. in dlz_mysql_init below. */
static dns_sdlzmethods_t dlz_mysql_methods = {
    mysql_create,
    mysql_destroy,
    mysql_findzone,
    mysql_lookup,
    mysql_authority,
    mysql_allnodes,
    mysql_allowzonexfr,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
};

/*%
 * Wrapper around dns_sdlzregister().
 */
isc_result_t
dlz_mysql_init(void) {
    isc_result_t result;

    /*
     * Write debugging message to log
     */
    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
              DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
              "Registering DLZ mysql driver.");

    /* Driver is always threadsafe.  Because of the way MySQL handles
         * threads the MySQL driver can only be used when bind is run single
         * threaded.  Using MySQL with Bind running multi-threaded is not
         * allowed.  When using the MySQL driver "-n1" should always be
         * passed to Bind to guarantee single threaded operation.
     */
    result = dns_sdlzregister("mysql", &dlz_mysql_methods, NULL,
                  DNS_SDLZFLAG_RELATIVEOWNER |
                  DNS_SDLZFLAG_RELATIVERDATA |
                  DNS_SDLZFLAG_THREADSAFE,
                  ns_g_mctx, &dlz_mysql);
    /* if we can't register the driver, there are big problems. */
    if (result != ISC_R_SUCCESS) {
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "dns_sdlzregister() failed: %s",
                 isc_result_totext(result));
        result = ISC_R_UNEXPECTED;
    }


    return result;
}

/*%
 * Wrapper around dns_sdlzunregister().
 */
void
dlz_mysql_clear(void) {

    /*
     * Write debugging message to log
     */
    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
              DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
              "Unregistering DLZ mysql driver.");

    /* unregister the driver. */
    if (dlz_mysql != NULL)
        dns_sdlzunregister(&dlz_mysql);
}

#endif