Remove building with NOCRYPTO option

[minix.git] / external / bsd / bind / dist / contrib / dlz / modules / mysql / dlz_mysql_dynamic.c

/*      $NetBSD: dlz_mysql_dynamic.c,v 1.1.1.3 2014/12/10 03:34:31 christos Exp $       */

/*
 * 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.
 * Copyright (C) 2013  Internet Systems 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.
 */

/*
 * This provides the externally loadable MySQL DLZ module, without
 * update support
 */

#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdlib.h>

#include <dlz_minimal.h>
#include <dlz_list.h>
#include <dlz_dbi.h>
#include <dlz_pthread.h>

#include <mysql/mysql.h>

#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

/*%
 * Structure to hold everthing needed by this "instance" of the MySQL
 * module remember, the module code is only loaded once, but may have
 * many separate instances.
 */
typedef struct {
#if PTHREADS
        db_list_t    *db; /*%< handle to a list of DB */
        int dbcount;
#else
        dbinstance_t *db; /*%< handle to DB */
#endif

        unsigned int flags;
        char *dbname;
        char *host;
        char *user;
        char *pass;
        char *socket;
        int port;

        /* Helper functions from the dlz_dlopen driver */
        log_t *log;
        dns_sdlz_putrr_t *putrr;
        dns_sdlz_putnamedrr_t *putnamedrr;
        dns_dlz_writeablezone_t *writeable_zone;
} mysql_instance_t;

/* forward references */
isc_result_t
dlz_findzonedb(void *dbdata, const char *name,
               dns_clientinfomethods_t *methods,
               dns_clientinfo_t *clientinfo);

void
dlz_destroy(void *dbdata);

static void
b9_add_helper(mysql_instance_t *db, const char *helper_name, void *ptr);

/*
 * Private methods
 */

void
mysql_destroy(dbinstance_t *db) {
        /* release DB connection */
        if (db->dbconn != NULL)
                mysql_close((MYSQL *) db->dbconn);

        /* destroy DB instance */
        destroy_dbinstance(db);
}

#if PTHREADS
/*%
 * Properly cleans up a list of database instances.
 * This function is only used when the module is compiled for
 * multithreaded operation.
 */
static void
mysql_destroy_dblist(db_list_t *dblist) {
        dbinstance_t *ndbi = NULL;
        dbinstance_t *dbi = NULL;

        ndbi = DLZ_LIST_HEAD(*dblist);
        while (ndbi != NULL) {
                dbi = ndbi;
                ndbi = DLZ_LIST_NEXT(dbi, link);

                mysql_destroy(dbi);
        }

        /* release memory for the list structure */
        free(dblist);
}

/*%
 * Loops through the list of DB instances, attempting to lock
 * on the mutex.  If successful, the DBI is reserved for use
 * and the thread can perform queries against the database.
 * If the lock fails, the next one in the list is tried.
 * looping continues until a lock is obtained, or until
 * the list has been searched dbc_search_limit times.
 * This function is only used when the module is compiled for
 * multithreaded operation.
 */
static dbinstance_t *
mysql_find_avail_conn(mysql_instance_t *mysql) {
        dbinstance_t *dbi = NULL, *head;
        int count = 0;

        /* get top of list */
        head = dbi = DLZ_LIST_HEAD(*(mysql->db));

        /* loop through list */
        while (count < dbc_search_limit) {
                /* try to lock on the mutex */
                if (dlz_mutex_trylock(&dbi->lock) == 0)
                        return (dbi); /* success, return the DBI for use. */

                /* not successful, keep trying */
                dbi = DLZ_LIST_NEXT(dbi, link);

                /* check to see if we have gone to the top of the list. */
                if (dbi == NULL) {
                        count++;
                        dbi = head;
                }
        }

        mysql->log(ISC_LOG_INFO,
                   "MySQL module unable to find available connection "
                   "after searching %d times", count);
        return (NULL);
}
#endif /* PTHREADS */

/*%
 * 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 = malloc((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 module.   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;
        mysql_instance_t *db = (mysql_instance_t *)dbdata;
        char *querystring = NULL;
        unsigned int i = 0;
        unsigned int j = 0;
        int qres = 0;

#if PTHREADS
        /* find an available DBI from the list */
        dbi = mysql_find_avail_conn(db);
#else /* PTHREADS */
        /*
         * only 1 DBI - no need to lock instance lock either
         * only 1 thread in the whole process, no possible contention.
         */
        dbi = (dbinstance_t *)(db->db);
#endif /* PTHREADS */

        if (dbi == NULL) {
                result = ISC_R_FAILURE;
                goto cleanup;
        }

        /* what type of query are we going to run? */
        switch(query) {
        case ALLNODES:
                if (dbi->allnodes_q == NULL) {
                        result = ISC_R_NOTIMPLEMENTED;
                        goto cleanup;
                }
                break;
        case ALLOWXFR:
                if (dbi->allowxfr_q == NULL) {
                        result = ISC_R_NOTIMPLEMENTED;
                        goto cleanup;
                }
                break;
        case AUTHORITY:
                if (dbi->authority_q == NULL) {
                        result = ISC_R_NOTIMPLEMENTED;
                        goto cleanup;
                }
                break;
        case FINDZONE:
                if (dbi->findzone_q == NULL) {
                        db->log(ISC_LOG_DEBUG(2),
                                "No query specified for findzone.  "
                                "Findzone requires a query");
                        result = ISC_R_FAILURE;
                        goto cleanup;
                }
                break;
        case COUNTZONE:
                if (dbi->countzone_q == NULL) {
                        result = ISC_R_NOTIMPLEMENTED;
                        goto cleanup;
                }
                break;
        case LOOKUP:
                if (dbi->lookup_q == NULL) {
                        db->log(ISC_LOG_DEBUG(2),
                                "No query specified for lookup.  "
                                "Lookup requires a query");
                        result = ISC_R_FAILURE;
                        goto cleanup;
                }
                break;
        default:
                db->log(ISC_LOG_ERROR,
                        "Incorrect query flag passed to "
                        "mysql_get_resultset");
                result = ISC_R_UNEXPECTED;
                goto cleanup;
        }


        if (zone != NULL) {
                if (dbi->zone != NULL)
                        free(dbi->zone);

                dbi->zone = mysqldrv_escape_string((MYSQL *) dbi->dbconn,
                                                   zone);
                if (dbi->zone == NULL) {
                        result = ISC_R_NOMEMORY;
                        goto cleanup;
                }
        } else
                dbi->zone = NULL;

        if (record != NULL) {
                if (dbi->record != NULL)
                        free(dbi->record);

                dbi->record = mysqldrv_escape_string((MYSQL *) dbi->dbconn,
                                                     record);
                if (dbi->record == NULL) {
                        result = ISC_R_NOMEMORY;
                        goto cleanup;
                }
        } else
                dbi->record = NULL;

        if (client != NULL) {
                if (dbi->client != NULL)
                        free(dbi->client);

                dbi->client = mysqldrv_escape_string((MYSQL *) dbi->dbconn,
                                                     client);
                if (dbi->client == NULL) {
                        result = ISC_R_NOMEMORY;
                        goto cleanup;
                }
        } else
                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(dbi->allnodes_q);
                break;
        case ALLOWXFR:
                querystring = build_querystring(dbi->allowxfr_q);
                break;
        case AUTHORITY:
                querystring = build_querystring(dbi->authority_q);
                break;
        case FINDZONE:
                querystring = build_querystring(dbi->findzone_q);
                break;
        case COUNTZONE:
                querystring = build_querystring(dbi->countzone_q);
                break;
        case LOOKUP:
                querystring = build_querystring(dbi->lookup_q);
                break;
        default:
                db->log(ISC_LOG_ERROR,
                        "Incorrect query flag passed to "
                        "mysql_get_resultset");
                result = ISC_R_UNEXPECTED; goto cleanup;
        }

        if (querystring == NULL) {
                result = ISC_R_NOMEMORY;
                goto cleanup;
        }

        /* output the full query string when debugging */
        db->log(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; j < 4; j++)
                     if (mysql_ping((MYSQL *) dbi->dbconn) == 0)
                             break;
        }

        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:
        if (dbi == NULL)
                return (ISC_R_FAILURE);

        if (dbi->zone != NULL) {
                free(dbi->zone);
                dbi->zone = NULL;
        }
        if (dbi->record != NULL) {
                free(dbi->record);
                dbi->record = NULL;
        }
        if (dbi->client != NULL) {
                free(dbi->client);
                dbi->client = NULL;
        }

        /* release the lock so another thread can use this dbi */
        (void) dlz_mutex_unlock(&dbi->lock);

        if (querystring != NULL)
                free(querystring);

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

        fields = mysql_num_fields(rs);  /* how many columns in result set */
        row = mysql_fetch_row(rs);      /* get a row from the result set */
        while (row != NULL) {
                unsigned int len = 0;

                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 = db->putrr(lookup, "a", 86400, safeGet(row[0]));
                        break;
                case 2:
                        /*
                         * two columns, data field, and data type.
                         * use default TTL of 86400.
                         */
                        result = db->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) {
                                db->log(ISC_LOG_ERROR,
                                        "MySQL module ttl must be "
                                        "a postive number");
                                return (ISC_R_FAILURE);
                        }

                        result = db->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; j < fields; j++)
                                len += strlen(safeGet(row[j])) + 1;

                        /*
                         * allocate string memory, allow for NULL to
                         * term string
                         */
                        tmpString = malloc(len + 1);
                        if (tmpString == NULL) {
                                db->log(ISC_LOG_ERROR,
                                        "MySQL module unable to allocate "
                                        "memory for temporary string");
                                mysql_free_result(rs);
                                return (ISC_R_FAILURE);
                        }

                        strcpy(tmpString, safeGet(row[2]));
                        for (j = 3; j < fields; j++) {
                                strcat(tmpString, " ");
                                strcat(tmpString, safeGet(row[j]));
                        }

                        ttl = strtol(safeGet(row[0]), &endp, 10);
                        if (*endp != '\0' || ttl < 0) {
                                db->log(ISC_LOG_ERROR,
                                        "MySQL module ttl must be "
                                        "a postive number");
                                return (ISC_R_FAILURE);
                        }

                        result = db->putrr(lookup, safeGet(row[1]),
                                           ttl, tmpString);
                        free(tmpString);
                }

                if (result != ISC_R_SUCCESS) {
                        mysql_free_result(rs);
                        db->log(ISC_LOG_ERROR,
                                "putrr returned error: %d", result);
                        return (ISC_R_FAILURE);
                }

                row = mysql_fetch_row(rs);
        }

        mysql_free_result(rs);
        return (result);
}

/*
 * DLZ methods
 */

/*% determine if the zone is supported by (in) the database */
isc_result_t
dlz_findzonedb(void *dbdata, const char *name,
               dns_clientinfomethods_t *methods,
               dns_clientinfo_t *clientinfo)
{
        isc_result_t result;
        MYSQL_RES *rs = NULL;
        my_ulonglong rows;
        mysql_instance_t *db = (mysql_instance_t *)dbdata;

        UNUSED(methods);
        UNUSED(clientinfo);

        result = mysql_get_resultset(name, NULL, NULL, FINDZONE, dbdata, &rs);
        if (result != ISC_R_SUCCESS || rs == NULL) {
                if (rs != NULL)
                        mysql_free_result(rs);

                db->log(ISC_LOG_ERROR,
                        "MySQL module unable to return "
                        "result set for findzone query");

                return (ISC_R_FAILURE);
        }

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

        return (ISC_R_NOTFOUND);
}

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

        /* first check if the zone is supported by the database. */
        result = dlz_findzonedb(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.
         */
        result = mysql_get_resultset(name, NULL, client, ALLOWXFR,
                                     dbdata, &rs);
        if (result == ISC_R_NOTIMPLEMENTED)
                return (result);

        if (result != ISC_R_SUCCESS || rs == NULL) {
                if (rs != NULL)
                        mysql_free_result(rs);
                db->log(ISC_LOG_ERROR,
                        "MySQL module unable to return "
                        "result set for allow xfr query");
                return (ISC_R_FAILURE);
        }

        /*
         * count how many rows in result set; if we returned any,
         * zone xfr is allowed.
         */
        rows = mysql_num_rows(rs);
        mysql_free_result(rs);
        if (rows > 0)
                return (ISC_R_SUCCESS);

        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.
 */
isc_result_t
dlz_allnodes(const char *zone, void *dbdata, dns_sdlzallnodes_t *allnodes) {
        isc_result_t result;
        mysql_instance_t *db = (mysql_instance_t *)dbdata;
        MYSQL_RES *rs = NULL;
        MYSQL_ROW row;
        unsigned int fields;
        unsigned int j;
        char *tmpString;
        char *endp;
        int ttl;

        result = mysql_get_resultset(zone, NULL, NULL, ALLNODES, dbdata, &rs);
        if (result == ISC_R_NOTIMPLEMENTED)
                return (result);

        /* if we didn't get a result set, log an err msg. */
        if (result != ISC_R_SUCCESS) {
                db->log(ISC_LOG_ERROR,
                        "MySQL module unable to return "
                        "result set for all nodes query");
                goto cleanup;
        }

        result = ISC_R_NOTFOUND;

        fields = mysql_num_fields(rs);  /* how many columns in result set */
        row = mysql_fetch_row(rs);      /* get a row from the result set */
        while (row != NULL) {
                if (fields < 4) {
                        db->log(ISC_LOG_ERROR,
                                "MySQL module too few fields returned "
                                "by all nodes query");
                        result = ISC_R_FAILURE;
                        goto cleanup;
                }

                ttl = strtol(safeGet(row[0]), &endp, 10);
                if (*endp != '\0' || ttl < 0) {
                        db->log(ISC_LOG_ERROR,
                                "MySQL module ttl must be "
                                "a postive number");
                        result = ISC_R_FAILURE;
                        goto cleanup;
                }

                if (fields == 4) {
                        result = db->putnamedrr(allnodes, safeGet(row[2]),
                                                safeGet(row[1]), ttl,
                                                safeGet(row[3]));
                } else {
                        unsigned int len = 0;

                        /*
                         * more than 4 fields, concatenate the last
                         * ones together.
                         */
                        for (j = 3; j < fields; j++)
                                len += strlen(safeGet(row[j])) + 1;

                        tmpString = malloc(len + 1);
                        if (tmpString == NULL) {
                                db->log(ISC_LOG_ERROR,
                                        "MySQL module unable to allocate "
                                        "memory for temporary string");
                                result = ISC_R_FAILURE;
                                goto cleanup;
                        }

                        strcpy(tmpString, safeGet(row[3]));
                        for (j = 4; j < fields; j++) {
                                strcat(tmpString, " ");
                                strcat(tmpString, safeGet(row[j]));
                        }

                        result = db->putnamedrr(allnodes, safeGet(row[2]),
                                                safeGet(row[1]),
                                                ttl, tmpString);
                        free(tmpString);
                }

                if (result != ISC_R_SUCCESS) {
                        db->log(ISC_LOG_ERROR,
                                "putnamedrr returned error: %s", result);
                        result = ISC_R_FAILURE;
                        break;
                }

                row = mysql_fetch_row(rs);
        }

 cleanup:
        if (rs != NULL)
                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 named.
 */
isc_result_t
dlz_authority(const char *zone, void *dbdata, dns_sdlzlookup_t *lookup) {
        isc_result_t result;
        MYSQL_RES *rs = NULL;
        mysql_instance_t *db = (mysql_instance_t *)dbdata;

        result = mysql_get_resultset(zone, NULL, NULL, AUTHORITY, dbdata, &rs);
        if (result == ISC_R_NOTIMPLEMENTED)
                return (result);

        if (result != ISC_R_SUCCESS) {
                if (rs != NULL)
                        mysql_free_result(rs);
                db->log(ISC_LOG_ERROR,
                        "MySQL module 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(db, lookup, rs));
}

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

        UNUSED(methods);
        UNUSED(clientinfo);

        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);
                db->log(ISC_LOG_ERROR,
                        "MySQL module 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(db, lookup, rs));
}

/*%
 * Create an instance of the module.
 */
isc_result_t
dlz_create(const char *dlzname, unsigned int argc, char *argv[],
           void **dbdata, ...)
{
        isc_result_t result = ISC_R_FAILURE;
        mysql_instance_t *mysql = NULL;
        dbinstance_t *dbi = NULL;
        MYSQL *dbc;
        char *tmp = NULL;
        char *endp;
        int j;
        const char *helper_name;
#if MYSQL_VERSION_ID >= 50000
        my_bool auto_reconnect = 1;
#endif
#if PTHREADS
        int dbcount;
        int i;
#endif /* PTHREADS */
        va_list ap;

        UNUSED(dlzname);

        /* allocate memory for MySQL instance */
        mysql = calloc(1, sizeof(mysql_instance_t));
        if (mysql == NULL)
                return (ISC_R_NOMEMORY);
        memset(mysql, 0, sizeof(mysql_instance_t));

        /* Fill in the helper functions */
        va_start(ap, dbdata);
        while ((helper_name = va_arg(ap, const char*)) != NULL)
                b9_add_helper(mysql, helper_name, va_arg(ap, void*));
        va_end(ap);

#if PTHREADS
        /* if debugging, let user know we are multithreaded. */
        mysql->log(ISC_LOG_DEBUG(1), "MySQL module running multithreaded");
#else /* PTHREADS */
        /* if debugging, let user know we are single threaded. */
        mysql->log(ISC_LOG_DEBUG(1), "MySQL module running single threaded");
#endif /* PTHREADS */

        /* verify we have at least 4 arg's passed to the module */
        if (argc < 4) {
                mysql->log(ISC_LOG_ERROR,
                           "MySQL module requires "
                           "at least 4 command line args.");
                return (ISC_R_FAILURE);
        }

        /* no more than 8 arg's should be passed to the module */
        if (argc > 8) {
                mysql->log(ISC_LOG_ERROR,
                           "MySQL module cannot accept "
                           "more than 7 command line args.");
                return (ISC_R_FAILURE);
        }

        /* get db name - required */
        mysql->dbname = get_parameter_value(argv[1], "dbname=");
        if (mysql->dbname == NULL) {
                mysql->log(ISC_LOG_ERROR,
                           "MySQL module requires a dbname parameter.");
                result = ISC_R_FAILURE;
                goto cleanup;
        }

        /* get db port.  Not required, but must be > 0 if specified */
        tmp = get_parameter_value(argv[1], "port=");
        if (tmp == NULL)
                mysql->port = 0;
        else {
                mysql->port = strtol(tmp, &endp, 10);
                if (*endp != '\0' || mysql->port < 0) {
                        mysql->log(ISC_LOG_ERROR,
                                   "Mysql module: port "
                                   "must be a positive number.");
                        free(tmp);
                        result = ISC_R_FAILURE;
                        goto cleanup;
                }
                free(tmp);
        }

        mysql->host = get_parameter_value(argv[1], "host=");
        mysql->user = get_parameter_value(argv[1], "user=");
        mysql->pass = get_parameter_value(argv[1], "pass=");
        mysql->socket = get_parameter_value(argv[1], "socket=");

        mysql->flags = CLIENT_REMEMBER_OPTIONS;

        tmp = get_parameter_value(argv[1], "compress=");
        if (tmp != NULL) {
                if (strcasecmp(tmp, "true") == 0)
                        mysql->flags |= CLIENT_COMPRESS;
                free(tmp);
        }

        tmp = get_parameter_value(argv[1], "ssl=");
        if (tmp != NULL) {
                if (strcasecmp(tmp, "true") == 0)
                        mysql->flags |= CLIENT_SSL;
                free(tmp);
        }

        tmp = get_parameter_value(argv[1], "space=");
        if (tmp != NULL) {
                if (strcasecmp(tmp, "ignore") == 0)
                        mysql->flags |= CLIENT_IGNORE_SPACE;
                free(tmp);
        }

#if PTHREADS
        /* multithreaded build can have multiple DB connections */
        tmp = get_parameter_value(argv[1], "threads=");
        if (tmp == NULL)
                dbcount = 1;
        else {
                dbcount = strtol(tmp, &endp, 10);
                if (*endp != '\0' || dbcount < 1) {
                        mysql->log(ISC_LOG_ERROR,
                                   "MySQL database connection count "
                                   "must be positive.");
                        free(tmp);
                        result = ISC_R_FAILURE;
                        goto cleanup;
                }
                free(tmp);
        }

        /* allocate memory for database connection list */
        mysql->db = calloc(1, sizeof(db_list_t));
        if (mysql->db == NULL) {
                result = ISC_R_NOMEMORY;
                goto cleanup;
        }

        /* initialize DB connection list */
        DLZ_LIST_INIT(*(mysql->db));

        /*
         * create the appropriate number of database instances (DBI)
         * append each new DBI to the end of the list
         */
        for (i = 0; i < dbcount; i++) {
#endif /* PTHREADS */
                switch(argc) {
                case 4:
                        result = build_dbinstance(NULL, NULL, NULL,
                                                  argv[2], argv[3], NULL,
                                                  &dbi, mysql->log);
                        break;
                case 5:
                        result = build_dbinstance(NULL, NULL, argv[4],
                                                  argv[2], argv[3], NULL,
                                                  &dbi, mysql->log);
                        break;
                case 6:
                        result = build_dbinstance(argv[5], NULL, argv[4],
                                                  argv[2], argv[3], NULL,
                                                  &dbi, mysql->log);
                        break;
                case 7:
                        result = build_dbinstance(argv[5], argv[6], argv[4],
                                                  argv[2], argv[3], NULL,
                                                  &dbi, mysql->log);
                        break;
                case 8:
                        result = build_dbinstance(argv[5], argv[6], argv[4],
                                                  argv[2], argv[3], argv[7],
                                                  &dbi, mysql->log);
                        break;
                default:
                        result = ISC_R_FAILURE;
                }


                if (result != ISC_R_SUCCESS) {
                        mysql->log(ISC_LOG_ERROR,
                                   "MySQL module could not create "
                                   "database instance object.");
                        result = ISC_R_FAILURE;
                        goto cleanup;
                }

#if PTHREADS
                /* when multithreaded, build a list of DBI's */
                DLZ_LINK_INIT(dbi, link);
                DLZ_LIST_APPEND(*(mysql->db), dbi, link);
#else
                /*
                 * when single threaded, hold onto the one connection
                 * instance.
                 */
                mysql->db = dbi;
#endif

                /* create and set db connection */
                dbi->dbconn = mysql_init(NULL);
                if (dbi->dbconn == NULL) {
                        mysql->log(ISC_LOG_ERROR,
                                   "MySQL module could not allocate "
                                   "memory for database connection");
                        result = ISC_R_FAILURE;
                        goto cleanup;
                }

                dbc = NULL;

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

                for (j = 0; dbc == NULL && j < 4; j++) {
                        dbc = mysql_real_connect((MYSQL *) dbi->dbconn,
                                                 mysql->host, mysql->user,
                                                 mysql->pass, mysql->dbname,
                                                 mysql->port, mysql->socket,
                                                 mysql->flags);
                        if (dbc == NULL)
                                mysql->log(ISC_LOG_ERROR,
                                           "MySQL connection failed: %s",
                                           mysql_error((MYSQL *) dbi->dbconn));
                }

                if (dbc == NULL) {
                        mysql->log(ISC_LOG_ERROR,
                                   "MySQL module failed to create "
                                   "database connection after 4 attempts");
                        result = ISC_R_FAILURE;
                        goto cleanup;
                }

#if PTHREADS
                /* set DBI = null for next loop through. */
                dbi = NULL;
        }
#endif /* PTHREADS */

        *dbdata = mysql;

        return (ISC_R_SUCCESS);

 cleanup:
        dlz_destroy(mysql);

        return (result);
}

/*%
 * Destroy the module.
 */
void
dlz_destroy(void *dbdata) {
        mysql_instance_t *db = (mysql_instance_t *)dbdata;
#if PTHREADS
        /* cleanup the list of DBI's */
        if (db->db != NULL)
                mysql_destroy_dblist((db_list_t *)(db->db));
#else /* PTHREADS */
        mysql_destroy(db);
#endif /* PTHREADS */

        if (db->dbname != NULL)
                free(db->dbname);
        if (db->host != NULL)
                free(db->host);
        if (db->user != NULL)
                free(db->user);
        if (db->pass != NULL)
                free(db->pass);
        if (db->socket != NULL)
                free(db->socket);
}

/*
 * Return the version of the API
 */
int
dlz_version(unsigned int *flags) {
        *flags |= (DNS_SDLZFLAG_RELATIVEOWNER |
                   DNS_SDLZFLAG_RELATIVERDATA |
                   DNS_SDLZFLAG_THREADSAFE);
        return (DLZ_DLOPEN_VERSION);
}

/*
 * Register a helper function from the bind9 dlz_dlopen driver
 */
static void
b9_add_helper(mysql_instance_t *db, const char *helper_name, void *ptr) {
        if (strcmp(helper_name, "log") == 0)
                db->log = (log_t *)ptr;
        if (strcmp(helper_name, "putrr") == 0)
                db->putrr = (dns_sdlz_putrr_t *)ptr;
        if (strcmp(helper_name, "putnamedrr") == 0)
                db->putnamedrr = (dns_sdlz_putnamedrr_t *)ptr;
        if (strcmp(helper_name, "writeable_zone") == 0)
                db->writeable_zone = (dns_dlz_writeablezone_t *)ptr;
}