dlz_mysql_driver.c

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/*
 * Copyright (C) 2002 Stichting NLnet, Netherlands, [e-mail].
 *
 * 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)
{
	isc_result_t result;
	MYSQL_RES *rs = NULL;
	my_ulonglong rows;

	UNUSED(driverarg);

	/* 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. */