fix: address critical poller race conditions and data loss guards

- Add early exit in syslog_process.php if uniqueID is 0
- Optimize partition existence re-check logic
- Standardize on prepared statements for all batch operations

Author: somethingwithproof

functions.php

@@ -386,31 +386,31 @@ function syslog_partition_remove($table) {
 	}
 
 	$syslog_deleted = 0;
-	$number_of_partitions = syslog_db_fetch_assoc_prepared("SELECT *
-		FROM `information_schema`.`partitions`
-		WHERE table_schema = ?
-		AND table_name = ?
-		ORDER BY partition_ordinal_position",
-		array($syslogdb_default, $table)
-	);
-
 	$days = read_config_option('syslog_retention');
 
-	syslog_debug("There are currently '" . sizeof($number_of_partitions) . "' Syslog Partitions for '$table', We will keep '$days' of them.");
-
 	if ($days > 0) {
-		$user_partitions = sizeof($number_of_partitions) - 1;
-		if ($user_partitions >= $days) {
-			$lock_name = hash('sha256', $syslogdb_default . 'syslog_partition_remove.' . $table);
+		$lock_name = hash('sha256', $syslogdb_default . 'syslog_partition_remove.' . $table);
 
-			try {
-				$locked = syslog_db_fetch_cell_prepared('SELECT GET_LOCK(?, 10)', array($lock_name));
+		try {
+			$locked = syslog_db_fetch_cell_prepared('SELECT GET_LOCK(?, 10)', array($lock_name));
 
-				if ((int)$locked !== 1) {
-					cacti_log("SYSLOG WARNING: Failed to acquire partition remove lock for '$table'", false, 'SYSTEM');
-					return $syslog_deleted;
-				}
+			if ((int)$locked !== 1) {
+				cacti_log("SYSLOG WARNING: Failed to acquire partition remove lock for '$table'", false, 'SYSTEM');
+				return $syslog_deleted;
+			}
 
+			$number_of_partitions = syslog_db_fetch_assoc_prepared("SELECT *
+				FROM `information_schema`.`partitions`
+				WHERE table_schema = ?
+				AND table_name = ?
+				ORDER BY partition_ordinal_position",
+				array($syslogdb_default, $table)
+			);
+
+			syslog_debug("There are currently '" . sizeof($number_of_partitions) . "' Syslog Partitions for '$table', We will keep '$days' of them.");
+
+			$user_partitions = sizeof($number_of_partitions) - 1;
+			if ($user_partitions >= $days) {
 				$i = 0;
 				while ($user_partitions > $days) {
 					$oldest = $number_of_partitions[$i];
@@ -425,9 +425,9 @@ function syslog_partition_remove($table) {
 					$user_partitions--;
 					$syslog_deleted++;
 				}
-			} finally {
-				syslog_db_fetch_cell_prepared('SELECT RELEASE_LOCK(?)', array($lock_name));
 			}
+		} finally {
+			syslog_db_fetch_cell_prepared('SELECT RELEASE_LOCK(?)', array($lock_name));
 		}
 	}
 

syslog_process.php

@@ -160,6 +160,12 @@
 $uniqueID = $results['uniqueID'];
 $incoming = $results['incoming'];
 
+if ($uniqueID === 0) {
+	syslog_debug('No valid uniqueID obtained, skipping processing cycle');
+	unregister_process('syslog', 'master', $config['poller_id']);
+	exit(0);
+}
+
 /**
  * place new normalized values in various reference tables
  * syslog attempts to normalize things like: