diff options
author | Pierre Schmitz <pierre@archlinux.de> | 2013-01-18 16:46:04 +0100 |
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committer | Pierre Schmitz <pierre@archlinux.de> | 2013-01-18 16:46:04 +0100 |
commit | 63601400e476c6cf43d985f3e7b9864681695ed4 (patch) | |
tree | f7846203a952e38aaf66989d0a4702779f549962 /includes/filerepo/backend/lockmanager/LSLockManager.php | |
parent | 8ff01378c9e0207f9169b81966a51def645b6a51 (diff) |
Update to MediaWiki 1.20.2
this update includes:
* adjusted Arch Linux skin
* updated FluxBBAuthPlugin
* patch for https://bugzilla.wikimedia.org/show_bug.cgi?id=44024
Diffstat (limited to 'includes/filerepo/backend/lockmanager/LSLockManager.php')
-rw-r--r-- | includes/filerepo/backend/lockmanager/LSLockManager.php | 295 |
1 files changed, 0 insertions, 295 deletions
diff --git a/includes/filerepo/backend/lockmanager/LSLockManager.php b/includes/filerepo/backend/lockmanager/LSLockManager.php deleted file mode 100644 index b7ac743c..00000000 --- a/includes/filerepo/backend/lockmanager/LSLockManager.php +++ /dev/null @@ -1,295 +0,0 @@ -<?php - -/** - * Manage locks using a lock daemon server. - * - * Version of LockManager based on using lock daemon servers. - * This is meant for multi-wiki systems that may share files. - * All locks are non-blocking, which avoids deadlocks. - * - * All lock requests for a resource, identified by a hash string, will map - * to one bucket. Each bucket maps to one or several peer servers, each - * running LockServerDaemon.php, listening on a designated TCP port. - * A majority of peers must agree for a lock to be acquired. - * - * @ingroup LockManager - * @since 1.19 - */ -class LSLockManager extends LockManager { - /** @var Array Mapping of lock types to the type actually used */ - protected $lockTypeMap = array( - self::LOCK_SH => self::LOCK_SH, - self::LOCK_UW => self::LOCK_SH, - self::LOCK_EX => self::LOCK_EX - ); - - /** @var Array Map of server names to server config */ - protected $lockServers; // (server name => server config array) - /** @var Array Map of bucket indexes to peer server lists */ - protected $srvsByBucket; // (bucket index => (lsrv1, lsrv2, ...)) - - /** @var Array Map Server connections (server name => resource) */ - protected $conns = array(); - - protected $connTimeout; // float number of seconds - protected $session = ''; // random SHA-1 string - - /** - * Construct a new instance from configuration. - * - * $config paramaters include: - * 'lockServers' : Associative array of server names to configuration. - * Configuration is an associative array that includes: - * 'host' - IP address/hostname - * 'port' - TCP port - * 'authKey' - Secret string the lock server uses - * 'srvsByBucket' : Array of 1-16 consecutive integer keys, starting from 0, - * each having an odd-numbered list of server names (peers) as values. - * 'connTimeout' : Lock server connection attempt timeout. [optional] - * - * @param Array $config - */ - public function __construct( array $config ) { - $this->lockServers = $config['lockServers']; - // Sanitize srvsByBucket config to prevent PHP errors - $this->srvsByBucket = array_filter( $config['srvsByBucket'], 'is_array' ); - $this->srvsByBucket = array_values( $this->srvsByBucket ); // consecutive - - if ( isset( $config['connTimeout'] ) ) { - $this->connTimeout = $config['connTimeout']; - } else { - $this->connTimeout = 3; // use some sane amount - } - - $this->session = ''; - for ( $i = 0; $i < 5; $i++ ) { - $this->session .= mt_rand( 0, 2147483647 ); - } - $this->session = wfBaseConvert( sha1( $this->session ), 16, 36, 31 ); - } - - protected function doLock( array $paths, $type ) { - $status = Status::newGood(); - - $pathsToLock = array(); - // Get locks that need to be acquired (buckets => locks)... - foreach ( $paths as $path ) { - if ( isset( $this->locksHeld[$path][$type] ) ) { - ++$this->locksHeld[$path][$type]; - } elseif ( isset( $this->locksHeld[$path][self::LOCK_EX] ) ) { - $this->locksHeld[$path][$type] = 1; - } else { - $bucket = $this->getBucketFromKey( $path ); - $pathsToLock[$bucket][] = $path; - } - } - - $lockedPaths = array(); // files locked in this attempt - // Attempt to acquire these locks... - foreach ( $pathsToLock as $bucket => $paths ) { - // Try to acquire the locks for this bucket - $res = $this->doLockingRequestAll( $bucket, $paths, $type ); - if ( $res === 'cantacquire' ) { - // Resources already locked by another process. - // Abort and unlock everything we just locked. - foreach ( $paths as $path ) { - $status->fatal( 'lockmanager-fail-acquirelock', $path ); - } - $status->merge( $this->doUnlock( $lockedPaths, $type ) ); - return $status; - } elseif ( $res !== true ) { - // Couldn't contact any servers for this bucket. - // Abort and unlock everything we just locked. - foreach ( $paths as $path ) { - $status->fatal( 'lockmanager-fail-acquirelock', $path ); - } - $status->merge( $this->doUnlock( $lockedPaths, $type ) ); - return $status; - } - // Record these locks as active - foreach ( $paths as $path ) { - $this->locksHeld[$path][$type] = 1; // locked - } - // Keep track of what locks were made in this attempt - $lockedPaths = array_merge( $lockedPaths, $paths ); - } - - return $status; - } - - protected function doUnlock( array $paths, $type ) { - $status = Status::newGood(); - - foreach ( $paths as $path ) { - if ( !isset( $this->locksHeld[$path] ) ) { - $status->warning( 'lockmanager-notlocked', $path ); - } elseif ( !isset( $this->locksHeld[$path][$type] ) ) { - $status->warning( 'lockmanager-notlocked', $path ); - } else { - --$this->locksHeld[$path][$type]; - if ( $this->locksHeld[$path][$type] <= 0 ) { - unset( $this->locksHeld[$path][$type] ); - } - if ( !count( $this->locksHeld[$path] ) ) { - unset( $this->locksHeld[$path] ); // no SH or EX locks left for key - } - } - } - - // Reference count the locks held and release locks when zero - if ( !count( $this->locksHeld ) ) { - $status->merge( $this->releaseLocks() ); - } - - return $status; - } - - /** - * Get a connection to a lock server and acquire locks on $paths - * - * @param $lockSrv string - * @param $paths Array - * @param $type integer LockManager::LOCK_EX or LockManager::LOCK_SH - * @return bool Resources able to be locked - */ - protected function doLockingRequest( $lockSrv, array $paths, $type ) { - if ( $type == self::LOCK_SH ) { // reader locks - $type = 'SH'; - } elseif ( $type == self::LOCK_EX ) { // writer locks - $type = 'EX'; - } else { - return true; // ok... - } - - // Send out the command and get the response... - $keys = array_unique( array_map( 'LockManager::sha1Base36', $paths ) ); - $response = $this->sendCommand( $lockSrv, 'ACQUIRE', $type, $keys ); - - return ( $response === 'ACQUIRED' ); - } - - /** - * Send a command and get back the response - * - * @param $lockSrv string - * @param $action string - * @param $type string - * @param $values Array - * @return string|false - */ - protected function sendCommand( $lockSrv, $action, $type, $values ) { - $conn = $this->getConnection( $lockSrv ); - if ( !$conn ) { - return false; // no connection - } - $authKey = $this->lockServers[$lockSrv]['authKey']; - // Build of the command as a flat string... - $values = implode( '|', $values ); - $key = sha1( $this->session . $action . $type . $values . $authKey ); - // Send out the command... - if ( fwrite( $conn, "{$this->session}:$key:$action:$type:$values\n" ) === false ) { - return false; - } - // Get the response... - $response = fgets( $conn ); - if ( $response === false ) { - return false; - } - return trim( $response ); - } - - /** - * Attempt to acquire locks with the peers for a bucket - * - * @param $bucket integer - * @param $paths Array List of resource keys to lock - * @param $type integer LockManager::LOCK_EX or LockManager::LOCK_SH - * @return bool|string One of (true, 'cantacquire', 'srverrors') - */ - protected function doLockingRequestAll( $bucket, array $paths, $type ) { - $yesVotes = 0; // locks made on trustable servers - $votesLeft = count( $this->srvsByBucket[$bucket] ); // remaining peers - $quorum = floor( $votesLeft/2 + 1 ); // simple majority - // Get votes for each peer, in order, until we have enough... - foreach ( $this->srvsByBucket[$bucket] as $lockSrv ) { - // Attempt to acquire the lock on this peer - if ( !$this->doLockingRequest( $lockSrv, $paths, $type ) ) { - return 'cantacquire'; // vetoed; resource locked - } - ++$yesVotes; // success for this peer - if ( $yesVotes >= $quorum ) { - return true; // lock obtained - } - --$votesLeft; - $votesNeeded = $quorum - $yesVotes; - if ( $votesNeeded > $votesLeft ) { - // In "trust cache" mode we don't have to meet the quorum - break; // short-circuit - } - } - // At this point, we must not have meet the quorum - return 'srverrors'; // not enough votes to ensure correctness - } - - /** - * Get (or reuse) a connection to a lock server - * - * @param $lockSrv string - * @return resource - */ - protected function getConnection( $lockSrv ) { - if ( !isset( $this->conns[$lockSrv] ) ) { - $cfg = $this->lockServers[$lockSrv]; - wfSuppressWarnings(); - $errno = $errstr = ''; - $conn = fsockopen( $cfg['host'], $cfg['port'], $errno, $errstr, $this->connTimeout ); - wfRestoreWarnings(); - if ( $conn === false ) { - return null; - } - $sec = floor( $this->connTimeout ); - $usec = floor( ( $this->connTimeout - floor( $this->connTimeout ) ) * 1e6 ); - stream_set_timeout( $conn, $sec, $usec ); - $this->conns[$lockSrv] = $conn; - } - return $this->conns[$lockSrv]; - } - - /** - * Release all locks that this session is holding - * - * @return Status - */ - protected function releaseLocks() { - $status = Status::newGood(); - foreach ( $this->conns as $lockSrv => $conn ) { - $response = $this->sendCommand( $lockSrv, 'RELEASE_ALL', '', array() ); - if ( $response !== 'RELEASED_ALL' ) { - $status->fatal( 'lockmanager-fail-svr-release', $lockSrv ); - } - } - return $status; - } - - /** - * Get the bucket for resource path. - * This should avoid throwing any exceptions. - * - * @param $path string - * @return integer - */ - protected function getBucketFromKey( $path ) { - $prefix = substr( sha1( $path ), 0, 2 ); // first 2 hex chars (8 bits) - return intval( base_convert( $prefix, 16, 10 ) ) % count( $this->srvsByBucket ); - } - - /** - * Make sure remaining locks get cleared for sanity - */ - function __destruct() { - $this->releaseLocks(); - foreach ( $this->conns as $conn ) { - fclose( $conn ); - } - } -} |