DLZ PG segfaults

[David Ford]

David Ford wrote:
> Greetings,
> I set up DLZ yesterday w/ 9.4b2 and discovered that the DLZ code needed
> a bit of love.  PQclear(x) doesn't set x to NULL and some functions were
> testing for NULL and working on an invalid pointer.  So to be overly
> cautious rather than depend on obscure logic, I set x = NULL at every
> instance of PQclear() which solved the segfaults.
>
> Attached is a patch to accomplish this.
>
> David
>
>
>
>
> !DSPAM:1000,454a6144299291802529180!
>
>   
Apparently the attachment got removed by the list.  Here it is inline.


--- dlz_postgres_driver.c	2005-10-26 00:57:23.000000000 -0400
+++ /tmp/dlz_postgres_driver.c	2006-11-02 12:08:52.000000000 -0500
@@ -549,7 +549,10 @@
 			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 				      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
 				      "%d clearing rs", dlz_thread_num);
-			PQclear(*rs);	/* get rid of it */
+			if (*rs) {
+				PQclear(*rs);	/* get rid of it */
+				*rs = NULL;
+			}
 			/* in case this was the last attempt */
 			result = ISC_R_FAILURE;
 		}
@@ -681,7 +684,10 @@
 					      "Postgres driver unable to "
 					      "allocate memory for "
 					      "temporary string");
-				PQclear(rs);
+				if (rs) {
+					PQclear(rs);
+					rs=NULL;
+				}
 				return (ISC_R_FAILURE);	/* Yeah, I'd say! */
 			}
 			/* copy field to tmpString */
@@ -712,7 +718,10 @@
 		/* I sure hope we were successful */
 		if (result != ISC_R_SUCCESS) {
 			/* nope, get rid of the Result set, and log a msg */
-			PQclear(rs);
+			if (rs) {
+				PQclear(rs);
+				rs=NULL;
+			}
 			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 				      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
 				      "dns_sdlz_putrr returned error. "
@@ -723,7 +732,10 @@
 	}
 
 	/* free result set memory */
-	PQclear(rs);
+	if (rs) {
+		PQclear(rs);
+		rs=NULL;
+	}
 
 	/* if we did return results, we are successful */
 	if (rows > 0)
@@ -752,8 +764,10 @@
 					FINDZONE, dbdata, &rs);
 	/* if we didn't get a result set, log an err msg. */
 	if (result != ISC_R_SUCCESS) {
-		if (rs != NULL)
+		if (rs) {
 			PQclear(rs);
+			rs=NULL;
+		}
 		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
 			      "Postgres driver unable to return "
@@ -762,8 +776,12 @@
 	}
 	/* count how many rows in result set */
 	rows = PQntuples(rs);
+
 	/* get rid of result set, we are done with it. */
-	PQclear(rs);
+	if (rs) {
+		PQclear(rs);
+		rs=NULL;
+	}
 
 	/* if we returned any rows, zone is supported. */
 	if (rows > 0)
@@ -803,8 +821,10 @@
 		return result;
 	/* if we didn't get a result set, log an err msg. */
 	if (result != ISC_R_SUCCESS) {
-		if (rs != NULL)
+		if (rs) {
 			PQclear(rs);
+			rs=NULL;
+		}
 		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
 			      "Postgres driver unable to return "
@@ -813,8 +833,12 @@
 	}
 	/* count how many rows in result set */
 	rows = PQntuples(rs);
+	
 	/* get rid of result set, we are done with it. */
-	PQclear(rs);
+	if (rs) {
+		PQclear(rs);
+		rs=NULL;
+	}
 
 	/* if we returned any rows, zone xfr is allowed. */
 	if (rows > 0)
@@ -854,8 +878,10 @@
 		return result;
 	/* if we didn't get a result set, log an err msg. */
 	if (result != ISC_R_SUCCESS) {
-		if (rs != NULL)
+		if (rs) {
 			PQclear(rs);
+			rs=NULL;
+		}
 		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
 			      "Postgres driver unable to return "
@@ -905,7 +931,8 @@
 					      "Postgres driver unable to "
 					      "allocate memory for "
 					      "temporary string");
-				PQclear(rs);
+				if (rs)
+					PQclear(rs);
 				return (ISC_R_FAILURE);
 			}
 			/* copy this field to tmpString */
@@ -924,7 +951,10 @@
 		}
 		/* if we weren't successful, log err msg */
 		if (result != ISC_R_SUCCESS) {
-			PQclear(rs);
+			if (rs) {
+				PQclear(rs);
+				rs=NULL;
+			}
 			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 				      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
 				      "dns_sdlz_putnamedrr returned error. "
@@ -935,7 +965,10 @@
 	}
 
 	/* free result set memory */
-	PQclear(rs);
+	if (rs) {
+		PQclear(rs);
+		rs=NULL;
+	}
 
 	/* if we did return results, we are successful */
 	if (rows > 0)
@@ -967,8 +1000,10 @@
 		return result;
 	/* if we didn't get a result set, log an err msg. */
 	if (result != ISC_R_SUCCESS) {
-		if (rs != NULL)
+		if (rs) {
 			PQclear(rs);
+			rs=NULL;
+		}
 		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
 			      "Postgres driver unable to return "
@@ -997,8 +1032,10 @@
 	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)
+		if (rs) {
 			PQclear(rs);
+			rs=NULL;
+		}
 		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
 			      "Postgres driver unable to "