maintenance/findBadBlobs.php
<?php
/**
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @ingroup Maintenance
*/
use MediaWiki\Revision\RevisionArchiveRecord;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Revision\RevisionStore;
use MediaWiki\Revision\RevisionStoreRecord;
use MediaWiki\Revision\SlotRecord;
use MediaWiki\Status\Status;
use MediaWiki\Storage\BlobStore;
require_once __DIR__ . '/Maintenance.php';
/**
* Maintenance script for finding and marking bad content blobs.
*
* @ingroup Maintenance
*/
class FindBadBlobs extends Maintenance {
private RevisionStore $revisionStore;
private BlobStore $blobStore;
public function __construct() {
parent::__construct();
$this->setBatchSize( 1000 );
$this->addDescription( 'Find and mark bad content blobs. Marked blobs will be read as empty. '
. 'Use --scan-from to find revisions with bad blobs, use --mark to mark them.' );
$this->addOption( 'scan-from', 'Start scanning revisions at the given date. '
. 'Format: Anything supported by MediaWiki, e.g. YYYYMMDDHHMMSS or YYYY-MM-DDTHH:MM:SS',
false, true );
$this->addOption( 'revisions', 'A list of revision IDs to process, separated by comma or '
. 'colon or whitespace. Revisions belonging to deleted pages will work. '
. 'If set to "-" IDs are read from stdin, one per line.', false, true );
$this->addOption( 'limit', 'Maximum number of revisions for --scan-from to scan. '
. 'Default: 1000', false, true );
$this->addOption( 'mark', 'Mark the blob as "known bad", to avoid errors when '
. 'attempting to read it. The value given is the reason for marking the blob as bad, '
. 'typically a ticket ID. Requires --revisions to also be set.', false, true );
}
/**
* @return string
*/
private function getStartTimestamp() {
$tsOpt = $this->getOption( 'scan-from' );
if ( strlen( $tsOpt ) < 14 ) {
$this->fatalError( 'Bad timestamp: ' . $tsOpt
. ', please provide time and date down to the second.' );
}
$ts = wfTimestamp( TS_MW, $tsOpt );
if ( !$ts ) {
$this->fatalError( 'Bad timestamp: ' . $tsOpt );
}
return $ts;
}
/**
* @return int[]
*/
private function getRevisionIds() {
$opt = $this->getOption( 'revisions' );
if ( $opt === '-' ) {
$opt = stream_get_contents( STDIN );
if ( !$opt ) {
return [];
}
}
return $this->parseIntList( $opt );
}
/**
* @inheritDoc
*/
public function execute() {
$services = $this->getServiceContainer();
$this->revisionStore = $services->getRevisionStore();
$this->blobStore = $services->getBlobStore();
$this->setDBProvider( $services->getConnectionProvider() );
if ( $this->hasOption( 'revisions' ) ) {
if ( $this->hasOption( 'scan-from' ) ) {
$this->fatalError( 'Cannot use --revisions together with --scan-from' );
}
$ids = $this->getRevisionIds();
$count = $this->scanRevisionsById( $ids );
} elseif ( $this->hasOption( 'scan-from' ) ) {
if ( $this->hasOption( 'mark' ) ) {
$this->fatalError( 'Cannot use --mark with --scan-from, '
. 'use --revisions to specify revisions to mark.' );
}
$fromTimestamp = $this->getStartTimestamp();
$total = $this->getOption( 'limit', 1000 );
$count = $this->scanRevisionsByTimestamp( $fromTimestamp, $total );
$this->output( "The range of archive rows scanned is based on the range of revision IDs "
. "scanned in the revision table.\n" );
} else {
if ( $this->hasOption( 'mark' ) ) {
$this->fatalError( 'The --mark must be used together with --revisions' );
} else {
$this->fatalError( 'Must specify one of --revisions or --scan-from' );
}
}
if ( $this->hasOption( 'mark' ) ) {
$this->output( "Marked $count bad revisions.\n" );
} else {
$this->output( "Found $count bad revisions.\n" );
if ( $count > 0 ) {
$this->output( "On a unix/linux environment, you can use grep and cut to list of IDs\n" );
$this->output( "that can then be used with the --revisions option. E.g.\n" );
$this->output( " grep '! Found bad blob' | cut -s -f 3\n" );
}
}
}
/**
* @param string $fromTimestamp
* @param int $total
*
* @return int
*/
private function scanRevisionsByTimestamp( $fromTimestamp, $total ) {
$count = 0;
$lastRevId = 0;
$firstRevId = 0;
$lastTimestamp = $fromTimestamp;
$revisionRowsScanned = 0;
$archiveRowsScanned = 0;
$this->output( "Scanning revisions table, "
. "$total rows starting at rev_timestamp $fromTimestamp\n" );
while ( $revisionRowsScanned < $total ) {
$batchSize = min( $total - $revisionRowsScanned, $this->getBatchSize() );
$revisions = $this->loadRevisionsByTimestamp( $lastRevId, $lastTimestamp, $batchSize );
if ( !$revisions ) {
break;
}
foreach ( $revisions as $rev ) {
// we are sorting by timestamp, so we may encounter revision IDs out of sequence
$firstRevId = $firstRevId ? min( $firstRevId, $rev->getId() ) : $rev->getId();
$lastRevId = max( $lastRevId, $rev->getId() );
$count += $this->checkRevision( $rev );
}
$lastTimestamp = $rev->getTimestamp();
$batchSize = count( $revisions );
$revisionRowsScanned += $batchSize;
$this->output(
"\t- Scanned a batch of $batchSize revisions, "
. "up to revision $lastRevId ($lastTimestamp)\n"
);
$this->waitForReplication();
}
// NOTE: the archive table isn't indexed by timestamp, so the best we can do is use the
// revision ID just before the first revision ID we found above as the starting point
// of the scan, and scan up to on revision after the last revision ID we found above.
// If $firstRevId is 0, the loop body above didn't execute,
// so we should skip the one below as well.
$fromArchived = $this->getNextRevision( $firstRevId, '<', 'DESC' );
$maxArchived = $this->getNextRevision( $lastRevId, '>', 'ASC' );
$maxArchived = $maxArchived ?: PHP_INT_MAX;
$this->output( "Scanning archive table by ar_rev_id, $fromArchived to $maxArchived\n" );
while ( $firstRevId > 0 && $fromArchived < $maxArchived ) {
$batchSize = min( $total - $archiveRowsScanned, $this->getBatchSize() );
$revisions = $this->loadArchiveByRevisionId( $fromArchived, $maxArchived, $batchSize );
if ( !$revisions ) {
break;
}
/** @var RevisionRecord $rev */
foreach ( $revisions as $rev ) {
$count += $this->checkRevision( $rev );
}
$fromArchived = $rev->getId();
$batchSize = count( $revisions );
$archiveRowsScanned += $batchSize;
$this->output(
"\t- Scanned a batch of $batchSize archived revisions, "
. "up to revision $fromArchived ($lastTimestamp)\n"
);
$this->waitForReplication();
}
return $count;
}
/**
* @param int $afterId
* @param string $fromTimestamp
* @param int $batchSize
*
* @return RevisionStoreRecord[]
*/
private function loadRevisionsByTimestamp( int $afterId, string $fromTimestamp, $batchSize ) {
$db = $this->getReplicaDB();
$queryBuilder = $this->revisionStore->newSelectQueryBuilder( $db );
$rows = $queryBuilder->joinComment()
->where( $db->buildComparison( '>', [
'rev_timestamp' => $fromTimestamp,
'rev_id' => $afterId,
] ) )
->useIndex( [ 'revision' => 'rev_timestamp' ] )
->orderBy( [ 'rev_timestamp', 'rev_id' ] )
->limit( $batchSize )
->caller( __METHOD__ )->fetchResultSet();
$result = $this->revisionStore->newRevisionsFromBatch( $rows, [ 'slots' => true ] );
$this->handleStatus( $result );
$records = array_filter( $result->value );
'@phan-var RevisionStoreRecord[] $records';
return $records;
}
/**
* @param int $afterId
* @param int $uptoId
* @param int $batchSize
*
* @return RevisionArchiveRecord[]
*/
private function loadArchiveByRevisionId( int $afterId, int $uptoId, $batchSize ) {
$db = $this->getReplicaDB();
$rows = $this->revisionStore->newArchiveSelectQueryBuilder( $db )
->joinComment()
->where( [ "ar_rev_id > $afterId", "ar_rev_id <= $uptoId" ] )
->orderBy( 'ar_rev_id' )
->limit( $batchSize )
->caller( __METHOD__ )->fetchResultSet();
$result = $this->revisionStore->newRevisionsFromBatch(
$rows,
[ 'archive' => true, 'slots' => true ]
);
$this->handleStatus( $result );
$records = array_filter( $result->value );
'@phan-var RevisionArchiveRecord[] $records';
return $records;
}
/**
* Returns the revision ID next to $revId, according to $comp and $dir
*
* @param int $revId
* @param string $comp the comparator, either '<' or '>', to go with $dir
* @param string $dir the sort direction to go with $comp, either 'ARC' or 'DESC'
*
* @return int
*/
private function getNextRevision( int $revId, string $comp, string $dir ) {
$db = $this->getReplicaDB();
$next = $db->newSelectQueryBuilder()
->select( 'rev_id' )
->from( 'revision' )
->where( "rev_id $comp $revId" )
->orderBy( [ "rev_id" ], $dir )
->caller( __METHOD__ )
->fetchField();
return (int)$next;
}
/**
* @param array $ids
*
* @return int
*/
private function scanRevisionsById( array $ids ) {
$count = 0;
$total = count( $ids );
$this->output( "Scanning $total ids\n" );
foreach ( array_chunk( $ids, $this->getBatchSize() ) as $batch ) {
$revisions = $this->loadRevisionsById( $batch );
if ( !$revisions ) {
continue;
}
/** @var RevisionRecord $rev */
foreach ( $revisions as $rev ) {
$count += $this->checkRevision( $rev );
}
$batchSize = count( $revisions );
$this->output( "\t- Scanned a batch of $batchSize revisions\n" );
}
return $count;
}
/**
* @param int[] $ids
*
* @return RevisionRecord[]
*/
private function loadRevisionsById( array $ids ) {
$db = $this->getReplicaDB();
$queryBuilder = $this->revisionStore->newSelectQueryBuilder( $db );
$rows = $queryBuilder
->joinComment()
->where( [ 'rev_id' => $ids ] )
->caller( __METHOD__ )->fetchResultSet();
$result = $this->revisionStore->newRevisionsFromBatch( $rows, [ 'slots' => true ] );
$this->handleStatus( $result );
$revisions = array_filter( $result->value );
'@phan-var RevisionArchiveRecord[] $revisions';
// if not all revisions were found, check the archive table.
if ( count( $revisions ) < count( $ids ) ) {
$rows = $this->revisionStore->newArchiveSelectQueryBuilder( $db )
->joinComment()
->where( [ 'ar_rev_id' => array_diff( $ids, array_keys( $revisions ) ) ] )
->caller( __METHOD__ )->fetchResultSet();
$archiveResult = $this->revisionStore->newRevisionsFromBatch(
$rows,
[ 'slots' => true, 'archive' => true ]
);
$this->handleStatus( $archiveResult );
// don't use array_merge, since it will re-index
$revisions += array_filter( $archiveResult->value );
}
return $revisions;
}
/**
* @param RevisionRecord $rev
*
* @return int
*/
private function checkRevision( RevisionRecord $rev ) {
$count = 0;
foreach ( $rev->getSlots()->getSlots() as $slot ) {
$count += $this->checkSlot( $rev, $slot );
}
if ( $count === 0 && $this->hasOption( 'mark' ) ) {
$this->output( "\t# No bad blob found on revision {$rev->getId()}, skipped!\n" );
}
return $count;
}
/**
* @param RevisionRecord $rev
* @param SlotRecord $slot
*
* @return int
*/
private function checkSlot( RevisionRecord $rev, SlotRecord $slot ) {
$address = $slot->getAddress();
try {
$this->blobStore->getBlob( $address );
// nothing to do
return 0;
} catch ( Exception $ex ) {
$error = $ex->getMessage();
$type = get_class( $ex );
}
// NOTE: output the revision ID again at the end in a separate column for easy processing
// via the "cut" shell command.
$this->output( "\t! Found bad blob on revision {$rev->getId()} "
. "from {$rev->getTimestamp()} ({$slot->getRole()} slot): "
. "content_id={$slot->getContentId()}, address=<{$slot->getAddress()}>, "
. "error='$error', type='$type'. ID:\t{$rev->getId()}\n" );
if ( $this->hasOption( 'mark' ) ) {
$newAddress = $this->markBlob( $slot, $error );
$this->output( "\tChanged address to <$newAddress>\n" );
}
return 1;
}
/**
* @param SlotRecord $slot
* @param string|null $error
*
* @return false|string
*/
private function markBlob( SlotRecord $slot, string $error = null ) {
$args = [];
if ( $this->hasOption( 'mark' ) ) {
$args['reason'] = $this->getOption( 'mark' );
}
if ( $error ) {
$args['error'] = $error;
}
$address = $slot->getAddress() ?: 'empty';
$badAddress = 'bad:' . urlencode( $address );
if ( $args ) {
$badAddress .= '?' . wfArrayToCgi( $args );
}
$badAddress = substr( $badAddress, 0, 255 );
$dbw = $this->getPrimaryDB();
$dbw->newUpdateQueryBuilder()
->update( 'content' )
->set( [ 'content_address' => $badAddress ] )
->where( [ 'content_id' => $slot->getContentId() ] )
->caller( __METHOD__ )->execute();
return $badAddress;
}
private function handleStatus( StatusValue $status ) {
if ( !$status->isOK() ) {
$this->fatalError(
Status::wrap( $status )->getMessage( false, false, 'en' )->text()
);
}
if ( !$status->isGood() ) {
$this->error(
"\t! " . Status::wrap( $status )->getMessage( false, false, 'en' )->text()
);
}
}
}
$maintClass = FindBadBlobs::class;
require_once RUN_MAINTENANCE_IF_MAIN;