Adding upstream version 1:9.16.44.upstream/1%9.16.44upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1240 insertions, 0 deletions

diff --git a/contrib/dlz/drivers/dlz_postgres_driver.c b/contrib/dlz/drivers/dlz_postgres_driver.c
new file mode 100644
index 0000000..d960c3f
--- /dev/null
+++ b/contrib/dlz/drivers/dlz_postgres_driver.c
@@ -0,0 +1,1240 @@
+/*
+ * Copyright (C) 2002 Stichting NLnet, Netherlands, stichting@nlnet.nl.
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0.  If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*
+ * Copyright (C) 1999-2001, 2016  Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifdef DLZ_POSTGRES
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.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 <dns/log.h>
+#include <dns/result.h>
+#include <dns/sdlz.h>
+
+#include <dlz/dlz_postgres_driver.h>
+#include <dlz/sdlz_helper.h>
+#include <named/globals.h>
+
+/* temporarily include time. */
+#include <libpq-fe.h>
+#include <time.h>
+
+static dns_sdlzimplementation_t *dlz_postgres = NULL;
+
+#define dbc_search_limit 30
+#define ALLNODES	 1
+#define ALLOWXFR	 2
+#define AUTHORITY	 3
+#define FINDZONE	 4
+#define LOOKUP		 5
+
+/*
+ * Private methods
+ */
+
+/* ---------------
+ * Escaping arbitrary strings to get valid SQL strings/identifiers.
+ *
+ * Replaces "\\" with "\\\\" and "'" with "''".
+ * length is the length of the buffer pointed to by
+ * from.  The buffer at to must be at least 2*length + 1 characters
+ * long.  A terminating NUL character is written.
+ *
+ * NOTICE!!!
+ * This function was borrowed directly from PostgreSQL's libpq.
+ * The function was originally called PQescapeString and renamed
+ * to postgres_makesafe to avoid a naming collision.
+ * PQescapeString is a new function made available in Postgres 7.2.
+ * For some reason the function is not properly exported on Win32
+ * builds making the function unavailable on Windows.  Also, since
+ * this function is new it would require building this driver with
+ * the libpq 7.2.  By borrowing this function the Windows problem
+ * is solved, and the dependence on libpq 7.2 is removed.  Libpq is
+ * still required of course, but an older version should work now too.
+ *
+ * The copyright statements from the original file containing this
+ * function are included below:
+ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ * ---------------
+ */
+
+static size_t
+postgres_makesafe(char *to, const char *from, size_t length) {
+	const char *source = from;
+	char *target = to;
+	unsigned int remaining = length;
+
+	while (remaining > 0) {
+		switch (*source) {
+		case '\\':
+			*target = '\\';
+			target++;
+			*target = '\\';
+			/* target and remaining are updated below. */
+			break;
+
+		case '\'':
+			*target = '\'';
+			target++;
+			*target = '\'';
+			/* target and remaining are updated below. */
+			break;
+
+		default:
+			*target = *source;
+			/* target and remaining are updated below. */
+		}
+		source++;
+		target++;
+		remaining--;
+	}
+
+	/* Write the terminating NUL character. */
+	*target = '\0';
+
+	return (target - to);
+}
+
+/*%
+ * Properly cleans up a list of database instances.
+ * This function is only used when the driver is compiled for
+ * multithreaded operation.
+ */
+static void
+postgres_destroy_dblist(db_list_t *dblist) {
+	dbinstance_t *ndbi = NULL;
+	dbinstance_t *dbi = NULL;
+
+	/* get the first DBI in the list */
+	ndbi = ISC_LIST_HEAD(*dblist);
+
+	/* loop through the list */
+	while (ndbi != NULL) {
+		dbi = ndbi;
+		/* get the next DBI in the list */
+		ndbi = ISC_LIST_NEXT(dbi, link);
+		/* release DB connection */
+		if (dbi->dbconn != NULL) {
+			PQfinish((PGconn *)dbi->dbconn);
+		}
+		/* release all memory that comprised a DBI */
+		destroy_sqldbinstance(dbi);
+	}
+	/* release memory for the list structure */
+	isc_mem_put(named_g_mctx, dblist, sizeof(db_list_t));
+}
+
+/*%
+ * 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 driver is compiled for
+ * multithreaded operation.
+ */
+
+static dbinstance_t *
+postgres_find_avail_conn(db_list_t *dblist) {
+	dbinstance_t *dbi = NULL;
+	dbinstance_t *head;
+	int count = 0;
+
+	/* get top of list */
+	head = dbi = ISC_LIST_HEAD(*dblist);
+
+	/* loop through list */
+	while (count < dbc_search_limit) {
+		/* try to lock on the mutex */
+		if (isc_mutex_trylock(&dbi->instance_lock) == ISC_R_SUCCESS) {
+			return (dbi); /* success, return the DBI for use. */
+		}
+		/* not successful, keep trying */
+		dbi = ISC_LIST_NEXT(dbi, link);
+
+		/* check to see if we have gone to the top of the list. */
+		if (dbi == NULL) {
+			count++;
+			dbi = head;
+		}
+	}
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DLZ,
+		      ISC_LOG_INFO,
+		      "Postgres driver unable to find available connection "
+		      "after searching %d times",
+		      count);
+	return (NULL);
+}
+
+/*%
+ * 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 *
+postgres_escape_string(const char *instr) {
+	char *outstr;
+	unsigned int len;
+
+	if (instr == NULL) {
+		return (NULL);
+	}
+
+	len = strlen(instr);
+
+	outstr = isc_mem_allocate(named_g_mctx, (2 * len * sizeof(char)) + 1);
+
+	postgres_makesafe(outstr, instr, len);
+	/* PQescapeString(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 either:
+ *		1) a list of database instances (in multithreaded mode) OR
+ *		2) a single database instance (in single threaded mode)
+ * The function will construct the query and obtain an available
+ * database instance (DBI).  It will then run the query and hopefully
+ * obtain a result set.  Postgres is nice, in that once the result
+ * set is returned, we can make the db connection available for another
+ * thread to use, while this thread continues on.  So, the DBI is made
+ * available ASAP by unlocking the instance_lock after we have cleaned
+ * it up properly.
+ */
+static isc_result_t
+postgres_get_resultset(const char *zone, const char *record, const char *client,
+		       unsigned int query, void *dbdata, PGresult **rs) {
+	isc_result_t result;
+	dbinstance_t *dbi = NULL;
+	char *querystring = NULL;
+	unsigned int i = 0;
+	unsigned int j = 0;
+
+#if 0
+	/* temporarily get a unique thread # */
+	unsigned int dlz_thread_num = 1 +
+				      (int) (1000.0 * rand() /
+					     (RAND_MAX + 1.0));
+#endif /* if 0 */
+
+	REQUIRE(*rs == NULL);
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d Getting DBI", dlz_thread_num);
+#endif /* if 0 */
+
+	/* get db instance / connection */
+
+	/* find an available DBI from the list */
+	dbi = postgres_find_avail_conn((db_list_t *)dbdata);
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d Got DBI - checking query", dlz_thread_num);
+#endif /* if 0 */
+
+	/* if DBI is null, can't do anything else */
+	if (dbi == NULL) {
+		return (ISC_R_FAILURE);
+	}
+
+	/* 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 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 "
+				 "postgres_get_resultset");
+		result = ISC_R_UNEXPECTED;
+		goto cleanup;
+	}
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d checked query", dlz_thread_num);
+#endif /* if 0 */
+
+	/*
+	 * was a zone string passed?  If so, make it safe for use in
+	 * queries.
+	 */
+	if (zone != NULL) {
+		dbi->zone = postgres_escape_string(zone);
+		if (dbi->zone == NULL) {
+			result = ISC_R_NOMEMORY;
+			goto cleanup;
+		}
+	} else { /* no string passed, set the string pointer to NULL */
+		dbi->zone = NULL;
+	}
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d did zone", dlz_thread_num);
+#endif /* if 0 */
+
+	/*
+	 * was a record string passed?  If so, make it safe for use in
+	 * queries.
+	 */
+	if (record != NULL) {
+		dbi->record = postgres_escape_string(record);
+		if (dbi->record == NULL) {
+			result = ISC_R_NOMEMORY;
+			goto cleanup;
+		}
+	} else { /* no string passed, set the string pointer to NULL */
+		dbi->record = NULL;
+	}
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d did record", dlz_thread_num);
+#endif /* if 0 */
+
+	/*
+	 * was a client string passed?  If so, make it safe for use in
+	 * queries.
+	 */
+	if (client != NULL) {
+		dbi->client = postgres_escape_string(client);
+		if (dbi->client == NULL) {
+			result = ISC_R_NOMEMORY;
+			goto cleanup;
+		}
+	} else { /* no string passed, set the string pointer to NULL */
+		dbi->client = NULL;
+	}
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d did client", dlz_thread_num);
+#endif /* if 0 */
+
+	/*
+	 * 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(named_g_mctx, dbi->allnodes_q);
+		break;
+	case ALLOWXFR:
+		querystring = build_querystring(named_g_mctx, dbi->allowxfr_q);
+		break;
+	case AUTHORITY:
+		querystring = build_querystring(named_g_mctx, dbi->authority_q);
+		break;
+	case FINDZONE:
+		querystring = build_querystring(named_g_mctx, dbi->findzone_q);
+		break;
+	case LOOKUP:
+		querystring = build_querystring(named_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 "
+				 "postgres_get_resultset");
+		result = ISC_R_UNEXPECTED;
+		goto cleanup;
+	}
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d built query", dlz_thread_num);
+#endif /* if 0 */
+
+	/* if the querystring is null, Bummer, outta RAM.  UPGRADE TIME!!!   */
+	if (querystring == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto cleanup;
+	}
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d query is '%s'", dlz_thread_num, querystring);
+#endif /* if 0 */
+
+	/*
+	 * 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 (j = 0; j < 3; j++) {
+#if 0
+		/* temporary logging message */
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+			      "%d executing query for %d time",
+			      dlz_thread_num, j);
+#endif /* if 0 */
+		/* try to get result set */
+		*rs = PQexec((PGconn *)dbi->dbconn, querystring);
+		result = ISC_R_SUCCESS;
+		/*
+		 * if result set is null, reset DB connection, max 3
+		 * attempts.
+		 */
+		for (i = 0; *rs == NULL && i < 3; i++) {
+#if 0
+			/* temporary logging message */
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+				      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+				      "%d resetting connection",
+				      dlz_thread_num);
+#endif /* if 0 */
+			result = ISC_R_FAILURE;
+			PQreset((PGconn *)dbi->dbconn);
+			/* connection ok, break inner loop */
+			if (PQstatus((PGconn *)dbi->dbconn) == CONNECTION_OK) {
+				break;
+			}
+		}
+		/* result set ok, break outer loop */
+		if (PQresultStatus(*rs) == PGRES_TUPLES_OK) {
+#if 0
+			/* temporary logging message */
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+				      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+				      "%d rs ok", dlz_thread_num);
+#endif /* if 0 */
+			break;
+		} else {
+			/* we got a result set object, but it's not right. */
+#if 0
+			/* temporary logging message */
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+				      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+				      "%d clearing rs", dlz_thread_num);
+#endif				      /* if 0 */
+			PQclear(*rs); /* get rid of it */
+			/* in case this was the last attempt */
+			*rs = NULL;
+			result = ISC_R_FAILURE;
+		}
+	}
+
+cleanup:
+	/* it's always good to cleanup after yourself */
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d cleaning up", dlz_thread_num);
+#endif /* if 0 */
+
+	/* free dbi->zone string */
+	if (dbi->zone != NULL) {
+		isc_mem_free(named_g_mctx, dbi->zone);
+	}
+
+	/* free dbi->record string */
+	if (dbi->record != NULL) {
+		isc_mem_free(named_g_mctx, dbi->record);
+	}
+
+	/* free dbi->client string */
+	if (dbi->client != NULL) {
+		isc_mem_free(named_g_mctx, dbi->client);
+	}
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d unlocking mutex", dlz_thread_num);
+#endif /* if 0 */
+
+	/* release the lock so another thread can use this dbi */
+	isc_mutex_unlock(&dbi->instance_lock);
+
+	/* release query string */
+	if (querystring != NULL) {
+		isc_mem_free(named_g_mctx, querystring);
+	}
+
+#if 0
+	/* temporary logging message */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+		      "%d returning", dlz_thread_num);
+#endif /* if 0 */
+
+	/* 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
+postgres_process_rs(dns_sdlzlookup_t *lookup, PGresult *rs) {
+	isc_result_t result;
+	unsigned int i;
+	unsigned int rows;
+	unsigned int fields;
+	unsigned int j;
+	unsigned int len;
+	char *tmpString;
+	char *endp;
+	int ttl;
+
+	rows = PQntuples(rs);	/* how many rows in result set */
+	fields = PQnfields(rs); /* how many columns in result set */
+	for (i = 0; i < rows; i++) {
+		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,
+						PQgetvalue(rs, i, 0));
+			break;
+		case 2:
+			/* two columns, data field, and data type.
+			 * use default TTL of 86400.
+			 */
+			result = dns_sdlz_putrr(lookup, PQgetvalue(rs, i, 0),
+						86400, PQgetvalue(rs, i, 1));
+			break;
+		case 3:
+			/* three columns, all data no defaults.
+			 * convert text to int, make sure it worked
+			 * right.
+			 */
+			ttl = strtol(PQgetvalue(rs, i, 0), &endp, 10);
+			if (*endp != '\0' || ttl < 0) {
+				isc_log_write(dns_lctx,
+					      DNS_LOGCATEGORY_DATABASE,
+					      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+					      "Postgres driver ttl must be "
+					      "a positive number");
+			}
+			result = dns_sdlz_putrr(lookup, PQgetvalue(rs, i, 1),
+						ttl, PQgetvalue(rs, i, 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(PQgetvalue(rs, i, j)) + 1;
+			}
+			/*
+			 * allocate string memory, allow for NULL to
+			 * term string
+			 */
+			tmpString = isc_mem_allocate(named_g_mctx, len + 1);
+			/* copy field to tmpString */
+			strcpy(tmpString, PQgetvalue(rs, i, 2));
+			/*
+			 * concat the rest of fields together, space
+			 * between each one.
+			 */
+			for (j = 3; j < fields; j++) {
+				strcat(tmpString, " ");
+				strcat(tmpString, PQgetvalue(rs, i, j));
+			}
+			/* convert text to int, make sure it worked right */
+			ttl = strtol(PQgetvalue(rs, i, 0), &endp, 10);
+			if (*endp != '\0' || ttl < 0) {
+				isc_log_write(dns_lctx,
+					      DNS_LOGCATEGORY_DATABASE,
+					      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+					      "Postgres driver ttl must be "
+					      "a positive number");
+			}
+			/* ok, now tell Bind about it. */
+			result = dns_sdlz_putrr(lookup, PQgetvalue(rs, i, 1),
+						ttl, tmpString);
+			/* done, get rid of this thing. */
+			isc_mem_free(named_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 */
+			PQclear(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);
+		}
+	}
+
+	/* free result set memory */
+	PQclear(rs);
+
+	/* if we did return results, we are successful */
+	if (rows > 0) {
+		return (ISC_R_SUCCESS);
+	}
+
+	/* empty result set, no data found */
+	return (ISC_R_NOTFOUND);
+}
+
+/*
+ * SDLZ interface methods
+ */
+
+/*% determine if the zone is supported by (in) the database */
+
+static isc_result_t
+postgres_findzone(void *driverarg, void *dbdata, const char *name,
+		  dns_clientinfomethods_t *methods,
+		  dns_clientinfo_t *clientinfo) {
+	isc_result_t result;
+	PGresult *rs = NULL;
+	unsigned int rows;
+
+	UNUSED(driverarg);
+	UNUSED(methods);
+	UNUSED(clientinfo);
+
+	/* run the query and get the result set from the database. */
+	result = postgres_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) {
+		if (rs != NULL) {
+			PQclear(rs);
+		}
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+			      "Postgres driver unable to return "
+			      "result set for findzone query");
+		return (ISC_R_FAILURE);
+	}
+	/* count how many rows in result set */
+	rows = PQntuples(rs);
+	/* get rid of result set, we are done with it. */
+	PQclear(rs);
+
+	/* if we returned any rows, zone is supported. */
+	if (rows > 0) {
+		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
+postgres_allowzonexfr(void *driverarg, void *dbdata, const char *name,
+		      const char *client) {
+	isc_result_t result;
+	PGresult *rs = NULL;
+	unsigned int rows;
+	UNUSED(driverarg);
+
+	/* first check if the zone is supported by the database. */
+	result = postgres_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 = postgres_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) {
+		if (rs != NULL) {
+			PQclear(rs);
+		}
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+			      "Postgres driver unable to return "
+			      "result set for allow xfr query");
+		return (ISC_R_FAILURE);
+	}
+	/* count how many rows in result set */
+	rows = PQntuples(rs);
+	/* get rid of result set, we are done with it. */
+	PQclear(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
+postgres_allnodes(const char *zone, void *driverarg, void *dbdata,
+		  dns_sdlzallnodes_t *allnodes) {
+	isc_result_t result;
+	PGresult *rs = NULL;
+	unsigned int i;
+	unsigned int rows;
+	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 = postgres_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) {
+			PQclear(rs);
+		}
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+			      "Postgres driver unable to return "
+			      "result set for all nodes query");
+		return (ISC_R_FAILURE);
+	}
+
+	rows = PQntuples(rs);	/* how many rows in result set */
+	fields = PQnfields(rs); /* how many columns in result set */
+	for (i = 0; i < rows; i++) {
+		if (fields < 4) { /* gotta have at least 4 columns */
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+				      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+				      "Postgres driver too few fields "
+				      "returned by all nodes query");
+		}
+		/* convert text to int, make sure it worked right  */
+		ttl = strtol(PQgetvalue(rs, i, 0), &endp, 10);
+		if (*endp != '\0' || ttl < 0) {
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+				      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+				      "Postgres driver ttl must be "
+				      "a positive number");
+		}
+		if (fields == 4) {
+			/* tell Bind about it. */
+			result = dns_sdlz_putnamedrr(allnodes,
+						     PQgetvalue(rs, i, 2),
+						     PQgetvalue(rs, i, 1), ttl,
+						     PQgetvalue(rs, i, 3));
+		} else {
+			/*
+			 * more than 4 fields, concatonat the last
+			 * ones together.  figure out how long to make
+			 * string
+			 */
+			for (j = 3, len = 0; j < fields; j++) {
+				len += strlen(PQgetvalue(rs, i, j)) + 1;
+			}
+			/* allocate memory, allow for NULL to term string */
+			tmpString = isc_mem_allocate(named_g_mctx, len + 1);
+			/* copy this field to tmpString */
+			strcpy(tmpString, PQgetvalue(rs, i, 3));
+			/* concatenate the rest, with spaces between */
+			for (j = 4; j < fields; j++) {
+				strcat(tmpString, " ");
+				strcat(tmpString, PQgetvalue(rs, i, j));
+			}
+			/* tell Bind about it. */
+			result = dns_sdlz_putnamedrr(
+				allnodes, PQgetvalue(rs, i, 2),
+				PQgetvalue(rs, i, 1), ttl, tmpString);
+			isc_mem_free(named_g_mctx, tmpString);
+		}
+		/* if we weren't successful, log err msg */
+		if (result != ISC_R_SUCCESS) {
+			PQclear(rs);
+			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));
+			return (ISC_R_FAILURE);
+		}
+	}
+
+	/* free result set memory */
+	PQclear(rs);
+
+	/* if we did return results, we are successful */
+	if (rows > 0) {
+		return (ISC_R_SUCCESS);
+	}
+
+	/* empty result set, no data found */
+	return (ISC_R_NOTFOUND);
+}
+
+/*%
+ * 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
+postgres_authority(const char *zone, void *driverarg, void *dbdata,
+		   dns_sdlzlookup_t *lookup) {
+	isc_result_t result;
+	PGresult *rs = NULL;
+
+	UNUSED(driverarg);
+
+	/* run the query and get the result set from the database. */
+	result = postgres_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) {
+			PQclear(rs);
+		}
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+			      "Postgres driver unable to return "
+			      "result set for authority query");
+		return (ISC_R_FAILURE);
+	}
+	/*
+	 * lookup and authority result sets are processed in the same
+	 * manner postgres_process_rs does the job for both
+	 * functions.
+	 */
+	return (postgres_process_rs(lookup, rs));
+}
+
+/*% if zone is supported, lookup up a (or multiple) record(s) in it */
+static isc_result_t
+postgres_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;
+	PGresult *rs = NULL;
+
+	UNUSED(driverarg);
+	UNUSED(methods);
+	UNUSED(clientinfo);
+
+	/* run the query and get the result set from the database. */
+	result = postgres_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) {
+			PQclear(rs);
+		}
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+			      "Postgres driver unable to "
+			      "return result set for lookup query");
+		return (ISC_R_FAILURE);
+	}
+	/*
+	 * lookup and authority result sets are processed in the same
+	 * manner postgres_process_rs does the job for both functions.
+	 */
+	return (postgres_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
+postgres_create(const char *dlzname, unsigned int argc, char *argv[],
+		void *driverarg, void **dbdata) {
+	isc_result_t result;
+	dbinstance_t *dbi = NULL;
+	unsigned int j;
+
+	/* if multi-threaded, we need a few extra variables. */
+	int dbcount;
+	db_list_t *dblist = NULL;
+	int i;
+	char *endp;
+
+	UNUSED(driverarg);
+	UNUSED(dlzname);
+
+	/* seed random # generator */
+	srand((unsigned)time(NULL));
+
+	/* if debugging, let user know we are multithreaded. */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DLZ,
+		      ISC_LOG_DEBUG(1),
+		      "Postgres driver running multithreaded");
+
+	/* verify we have at least 5 arg's passed to the driver */
+	if (argc < 5) {
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+			      "Postgres 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,
+			      "Postgres driver cannot accept more than "
+			      "7 command line args.");
+		return (ISC_R_FAILURE);
+	}
+
+	/* multithreaded build can have multiple DB connections */
+
+	/* check how many db connections we should create */
+	dbcount = strtol(argv[1], &endp, 10);
+	if (*endp != '\0' || dbcount < 0) {
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+			      "Postgres driver database connection count "
+			      "must be positive.");
+		return (ISC_R_FAILURE);
+	}
+
+	/* allocate memory for database connection list */
+	dblist = isc_mem_get(named_g_mctx, sizeof(db_list_t));
+
+	/* initialize DB connection list */
+	ISC_LIST_INIT(*dblist);
+
+	/*
+	 * create the appropriate number of database instances (DBI)
+	 * append each new DBI to the end of the list
+	 */
+	for (i = 0; i < dbcount; i++) {
+		/* how many queries were passed in from config file? */
+		switch (argc) {
+		case 5:
+			result = build_sqldbinstance(named_g_mctx, NULL, NULL,
+						     NULL, argv[3], argv[4],
+						     NULL, &dbi);
+			break;
+		case 6:
+			result = build_sqldbinstance(named_g_mctx, NULL, NULL,
+						     argv[5], argv[3], argv[4],
+						     NULL, &dbi);
+			break;
+		case 7:
+			result = build_sqldbinstance(named_g_mctx, argv[6],
+						     NULL, argv[5], argv[3],
+						     argv[4], NULL, &dbi);
+			break;
+		case 8:
+			result = build_sqldbinstance(named_g_mctx, argv[6],
+						     argv[7], argv[5], argv[3],
+						     argv[4], NULL, &dbi);
+			break;
+		default:
+			/* not really needed, should shut up compiler. */
+			result = ISC_R_FAILURE;
+		}
+
+		if (result == ISC_R_SUCCESS) {
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+				      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
+				      "Postgres driver created database "
+				      "instance object.");
+		} else { /* unsuccessful?, log err msg and cleanup. */
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+				      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+				      "Postgres driver could not create "
+				      "database instance object.");
+			goto cleanup;
+		}
+
+		/* when multithreaded, build a list of DBI's */
+		ISC_LINK_INIT(dbi, link);
+		ISC_LIST_APPEND(*dblist, dbi, link);
+
+		/* create and set db connection */
+		dbi->dbconn = PQconnectdb(argv[2]);
+		/*
+		 * 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,
+				      "Postgres driver could not allocate "
+				      "memory for database connection");
+			goto cleanup;
+		}
+
+		/* if we cannot connect the first time, try 3 more times. */
+		for (j = 0;
+		     PQstatus((PGconn *)dbi->dbconn) != CONNECTION_OK && j < 3;
+		     j++)
+		{
+			PQreset((PGconn *)dbi->dbconn);
+		}
+
+		/*
+		 * if multi threaded, let user know which connection
+		 * failed.  user could be attempting to create 10 db
+		 * connections and for some reason the db backend only
+		 * allows 9
+		 */
+		if (PQstatus((PGconn *)dbi->dbconn) != CONNECTION_OK) {
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+				      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+				      "Postgres driver failed to create "
+				      "database connection number %u "
+				      "after 4 attempts",
+				      i + 1);
+			goto cleanup;
+		}
+
+		/* set DBI = null for next loop through. */
+		dbi = NULL;
+	} /* end for loop */
+
+	/* set dbdata to the list we created. */
+	*dbdata = dblist;
+
+	/* hey, we got through all of that ok, return success. */
+	return (ISC_R_SUCCESS);
+
+cleanup:
+
+	/*
+	 * if multithreaded, we could fail because only 1 connection
+	 * couldn't be made.  We should cleanup the other successful
+	 * connections properly.
+	 */
+	postgres_destroy_dblist(dblist);
+
+	return (ISC_R_FAILURE);
+}
+
+/*%
+ * destroy 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.
+ * so we really only need to clean it up since we are not using driverarg.
+ */
+static void
+postgres_destroy(void *driverarg, void *dbdata) {
+	UNUSED(driverarg);
+	/* cleanup the list of DBI's */
+	postgres_destroy_dblist((db_list_t *)dbdata);
+}
+
+/* pointers to all our runtime methods. */
+/* this is used during driver registration */
+/* i.e. in dlz_postgres_init below. */
+static dns_sdlzmethods_t dlz_postgres_methods = {
+	postgres_create,
+	postgres_destroy,
+	postgres_findzone,
+	postgres_lookup,
+	postgres_authority,
+	postgres_allnodes,
+	postgres_allowzonexfr,
+	NULL,
+	NULL,
+	NULL,
+	NULL,
+	NULL,
+	NULL,
+	NULL,
+};
+
+/*%
+ * Wrapper around dns_sdlzregister().
+ */
+isc_result_t
+dlz_postgres_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 postgres driver.");
+
+	/*
+	 * Driver is always threadsafe.  When multithreaded all
+	 * functions use multithreaded code.  When not multithreaded,
+	 * all functions can only be entered once, but only 1 thread
+	 * of operation is available in Bind.  So everything is still
+	 * threadsafe.
+	 */
+	result = dns_sdlzregister("postgres", &dlz_postgres_methods, NULL,
+				  DNS_SDLZFLAG_RELATIVEOWNER |
+					  DNS_SDLZFLAG_RELATIVERDATA |
+					  DNS_SDLZFLAG_THREADSAFE,
+				  named_g_mctx, &dlz_postgres);
+	/* 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_postgres_clear(void) {
+	/*
+	 * Write debugging message to log
+	 */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DLZ,
+		      ISC_LOG_DEBUG(2), "Unregistering DLZ postgres driver.");
+
+	/* unregister the driver. */
+	if (dlz_postgres != NULL) {
+		dns_sdlzunregister(&dlz_postgres);
+	}
+}
+
+#endif /* ifdef DLZ_POSTGRES */