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bugfix: scope partition maintenance to target table and lock create path #271

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bugfix: scope partition maintenance to target table and lock create path #271

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177 changes: 137 additions & 40 deletions functions.php
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Original file line number Diff line number Diff line change
Expand Up @@ -187,86 +187,184 @@ function syslog_partition_manage() {
}

/**
* This function will create a new partition for the specified table.
* Validate tables that support partition maintenance.
*
* Any value added to the allowlist MUST match ^[a-z_]+$ so it is safe
* for identifier interpolation in DDL statements (MySQL does not support
* parameter binding for identifiers).
*/
function syslog_partition_table_allowed($table) {
if (!in_array($table, array('syslog', 'syslog_removed'), true)) {
return false;
}

/* Defense-in-depth: reject values unsafe for identifier interpolation. */
if (!preg_match('/^[a-z_]+$/', $table)) {
return false;
}

return true;
}

/**
* Create a new partition for the specified table.
*
* @return bool true on success, false on lock failure or disallowed table.
*/
function syslog_partition_create($table) {
global $syslogdb_default;

/* determine the format of the table name */
$time = time();
$cformat = 'd' . date('Ymd', $time);
$lnow = date('Y-m-d', $time+86400);
if (!syslog_partition_table_allowed($table)) {
return false;
}

$exists = syslog_db_fetch_row("SELECT *
FROM `information_schema`.`partitions`
WHERE table_schema='" . $syslogdb_default . "'
AND partition_name='" . $cformat . "'
AND table_name='syslog'
ORDER BY partition_ordinal_position");
/* Hash to guarantee the lock name stays within MySQL's 64-byte limit. */
$lock_name = substr(hash('sha256', $syslogdb_default . '.syslog_partition_create.' . $table), 0, 60);

if (!cacti_sizeof($exists)) {
cacti_log("SYSLOG: Creating new partition '$cformat'", false, 'SYSTEM');
/*
* 10-second timeout is sufficient: partition maintenance runs once per
* poller cycle (typically 5 minutes), so sustained contention is not
* expected. A failure is logged so monitoring can detect repeated misses.
*/
$locked = syslog_db_fetch_cell_prepared('SELECT GET_LOCK(?, 10)', array($lock_name));

syslog_debug("Creating new partition '$cformat'");
if ($locked === null) {
/* NULL means the GET_LOCK call itself failed, not just contention. */
cacti_log("SYSLOG: GET_LOCK call failed for partition create on '$table'", false, 'SYSTEM');
return false;
}

syslog_db_execute("ALTER TABLE `" . $syslogdb_default . "`.`$table` REORGANIZE PARTITION dMaxValue INTO (
PARTITION $cformat VALUES LESS THAN (TO_DAYS('$lnow')),
PARTITION dMaxValue VALUES LESS THAN MAXVALUE)");
if ((int)$locked !== 1) {
cacti_log("SYSLOG: Unable to acquire partition create lock for '$table'", false, 'SYSTEM');
return false;
}

try {
/* determine the format of the table name */
$time = time();
$cformat = 'd' . date('Ymd', $time);
$lnow = date('Y-m-d', $time+86400);

$exists = syslog_db_fetch_row_prepared("SELECT *
FROM `information_schema`.`partitions`
WHERE table_schema = ?
AND partition_name = ?
AND table_name = ?
ORDER BY partition_ordinal_position",
array($syslogdb_default, $cformat, $table));

if (!cacti_sizeof($exists)) {
cacti_log("SYSLOG: Creating new partition '$cformat'", false, 'SYSTEM');

syslog_debug("Creating new partition '$cformat'");

/*
* MySQL does not support parameter binding for DDL identifiers
* or partition definitions. $table is safe because it passed
* syslog_partition_table_allowed() (two-value allowlist plus
* regex guard). $cformat and $lnow derive from date() and
* contain only digits, hyphens, and the letter 'd'.
*/
syslog_db_execute("ALTER TABLE `" . $syslogdb_default . "`.`$table` REORGANIZE PARTITION dMaxValue INTO (
PARTITION $cformat VALUES LESS THAN (TO_DAYS('$lnow')),
PARTITION dMaxValue VALUES LESS THAN MAXVALUE)");
}
} finally {
syslog_db_fetch_cell_prepared('SELECT RELEASE_LOCK(?)', array($lock_name));
}

return true;
}

/**
* This function will remove all old partitions for the specified table.
* Remove old partitions for the specified table.
*/
function syslog_partition_remove($table) {
global $syslogdb_default;

if (!syslog_partition_table_allowed($table)) {
cacti_log("SYSLOG: partition_remove called with disallowed table '$table'", false, 'SYSTEM');
return 0;
}

$lock_name = substr(hash('sha256', $syslogdb_default . '.syslog_partition_remove.' . $table), 0, 60);

$locked = syslog_db_fetch_cell_prepared('SELECT GET_LOCK(?, 10)', array($lock_name));

if ($locked === null) {
cacti_log("SYSLOG: GET_LOCK call failed for partition remove on '$table'", false, 'SYSTEM');
return 0;
}

if ((int)$locked !== 1) {
cacti_log("SYSLOG: Unable to acquire partition remove lock for '$table'", false, 'SYSTEM');
return 0;
}

$syslog_deleted = 0;
$number_of_partitions = syslog_db_fetch_assoc("SELECT *
FROM `information_schema`.`partitions`
WHERE table_schema='" . $syslogdb_default . "' AND table_name='syslog'
ORDER BY partition_ordinal_position");

$days = read_config_option('syslog_retention');
try {
$number_of_partitions = syslog_db_fetch_assoc_prepared("SELECT *
FROM `information_schema`.`partitions`
WHERE table_schema = ? AND table_name = ?
ORDER BY partition_ordinal_position",
array($syslogdb_default, $table));

$days = read_config_option('syslog_retention');

syslog_debug("There are currently '" . sizeof($number_of_partitions) . "' Syslog Partitions, We will keep '$days' of them.");
syslog_debug("There are currently '" . sizeof($number_of_partitions) . "' Syslog Partitions, We will keep '$days' of them.");

if ($days > 0) {
$user_partitions = sizeof($number_of_partitions) - 1;
if ($user_partitions >= $days) {
$i = 0;
while ($user_partitions > $days) {
$oldest = $number_of_partitions[$i];
if ($days > 0) {
$user_partitions = sizeof($number_of_partitions) - 1;
if ($user_partitions >= $days) {
$i = 0;
while ($user_partitions > $days) {
$oldest = $number_of_partitions[$i];

cacti_log("SYSLOG: Removing old partition '" . $oldest['PARTITION_NAME'] . "'", false, 'SYSTEM');
cacti_log("SYSLOG: Removing old partition '" . $oldest['PARTITION_NAME'] . "'", false, 'SYSTEM');

syslog_debug("Removing partition '" . $oldest['PARTITION_NAME'] . "'");
syslog_debug("Removing partition '" . $oldest['PARTITION_NAME'] . "'");

syslog_db_execute("ALTER TABLE `" . $syslogdb_default . "`.`$table` DROP PARTITION " . $oldest['PARTITION_NAME']);
syslog_db_execute("ALTER TABLE `" . $syslogdb_default . "`.`$table` DROP PARTITION " . $oldest['PARTITION_NAME']);

$i++;
$user_partitions--;
$syslog_deleted++;
$i++;
$user_partitions--;
$syslog_deleted++;
}
}
}
} finally {
syslog_db_fetch_cell_prepared('SELECT RELEASE_LOCK(?)', array($lock_name));
}

return $syslog_deleted;
}

/*
* syslog_partition_check is a read-only SELECT against information_schema.
* It does not execute DDL, so it does not need the named lock that
* syslog_partition_create and syslog_partition_remove acquire. External
* serialization is provided by the poller cycle calling
* syslog_partition_manage().
*/
function syslog_partition_check($table) {
global $syslogdb_default;

if (!syslog_partition_table_allowed($table)) {
return false;
}

if (defined('SYSLOG_CONFIG')) {
include(SYSLOG_CONFIG);
}

/* find date of last partition */
$last_part = syslog_db_fetch_cell("SELECT PARTITION_NAME
$last_part = syslog_db_fetch_cell_prepared("SELECT PARTITION_NAME
FROM `information_schema`.`partitions`
WHERE table_schema='" . $syslogdb_default . "' AND table_name='syslog'
WHERE table_schema = ? AND table_name = ?
ORDER BY partition_ordinal_position DESC
LIMIT 1,1;");
LIMIT 1,1",
array($syslogdb_default, $table));

$lformat = str_replace('d', '', $last_part);
$cformat = date('Ymd');
Expand Down Expand Up @@ -2421,4 +2519,3 @@ function alert_replace_variables($alert, $results, $hostname = '') {

return $command;
}

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